JP4637472B2 - Method for manufacturing light emitting device - Google Patents

Description

  The present invention relates to a light-emitting device having a means for supplying current to a light-emitting element and the light-emitting element in each of a plurality of pixels, and a method for manufacturing the light-emitting device.

  Since the light emitting element emits light by itself, it has high visibility, is not required for a backlight necessary for a liquid crystal display device (LCD), is optimal for thinning, and has a feature that a viewing angle is wider than that of an LCD. Therefore, a light-emitting device using a light-emitting element has attracted attention as a display device that replaces a CRT or an LCD, and is being put into practical use. An OLED (Organic Light Emitting Diode), which is one of the light emitting elements, includes a layer containing an electroluminescent material (hereinafter referred to as an electroluminescent layer) from which luminescence is obtained by applying an electric field, an anode, and a cathode. have. Light emission can be obtained by combining holes injected from the anode and electrons injected from the cathode in the electroluminescent layer.

  As an example of a light-emitting device using such a light-emitting element, a passive matrix type can be given. A passive matrix light-emitting device is formed between a plurality of electrodes (row electrodes) extending in one direction, a plurality of electrodes (column electrodes) extending in a direction intersecting with the electrodes, and a plurality of row electrodes and a plurality of column electrodes. (For example, refer nonpatent literature 1). The light-emitting element corresponds to a portion where the row electrode, the column electrode, and the electroluminescent layer overlap each other, and a plurality of light-emitting elements are arranged in a matrix in the pixel portion.

C. W. C. T., et al., Journal of Applied Physics, Vol. 65, p. 3610, 1988

  Operation of the passive matrix light-emitting device is described. A passive matrix light-emitting device can select a plurality of light-emitting elements one by one by controlling the potentials of the plurality of row electrodes. Then, the selected light emitting elements for one row are further sequentially selected by video signals inputted to the plurality of column electrodes. That is, when focusing on one column electrode, a plurality of light emitting elements sharing the column electrode are further selected by a plurality of row electrodes. A current whose value is determined by the video signal is supplied to the selected light emitting element, and the luminance is controlled.

  By the way, the light emitting element has a property of accumulating electric charges between two electrodes like a capacitor element. Therefore, the current supplied to the pixel portion in the above operation is actually used to charge all the light emitting elements sharing the column electrode when supplied to the selected light emitting element. Only after the charging is completed, in the selected light emitting element, a current having an accurate value determined by the video signal is supplied to the electroluminescent layer.

  The problem here is that the amount of charge accumulated in the light-emitting element differs depending on the current value of the video signal, which causes a difference in the charging time of the light-emitting element. That is, the larger the amount of charge accumulated when a certain light emitting element is selected, the shorter the time required for charging when the light emitting element is next selected. Conversely, the smaller the amount of charge accumulated when a light emitting element is selected, the longer it takes to charge the next time the light emitting element is selected. The time required for charging is related to the time from when the current is supplied to the column electrode until the selected light emitting element emits light. Therefore, the variation in the charging time immediately appears as uneven luminance. . In particular, when the resolution is increased, the selection time per line is shortened, and this tendency becomes remarkable.

  When the number of light emitting elements is increased in order to increase the definition of the pixel portion, the number of light emitting elements sharing one column electrode naturally increases, and the combined capacitance formed by the light emitting elements increases. Therefore, the charging time until reaching the light emission becomes longer, and the merit of the electroluminescent material that the response speed is very high cannot be utilized.

  On the other hand, in the case of an active matrix light-emitting device in which the current supply to each light-emitting element can be controlled by a transistor, the selected light-emitting element and the other light-emitting elements can be electrically separated by the transistor. it can. Accordingly, only the selected light emitting element needs to be charged, so that the passive matrix type is less likely to vary in charging time, and uneven luminance can be suppressed. However, in the case of an active matrix light-emitting device, in order to form a transistor corresponding to each light-emitting element, the number of steps using a lithography method is increased compared to the passive matrix type, and the manufacturing process becomes complicated.

  In view of the above-described problems, the present invention prevents light emission non-uniformity due to variation in charging time, reduces the number of steps using a lithography method, and can be formed using a simpler manufacturing process. It is an object to provide a device and a method for manufacturing a light-emitting device.

  In the present invention, a transistor capable of electrically separating a selected light emitting element from another light emitting element is formed so as to be connected in series with the light emitting element. Specifically, in the light-emitting device of the present invention, a plurality of pixels are formed in a pixel portion in a matrix, and each pixel includes a light-emitting element and a thin film transistor (TFT) connected in series with the light-emitting element. ing. The operation of the TFT is controlled by a plurality of scanning lines, and pixels for one row are selected. The pixels for one row are selected sequentially or simultaneously by a plurality of signal lines, and the light emitting elements of the selected pixels emit light with a luminance corresponding to the current value of the video signal.

  In the light emitting device having the above configuration, one column of pixels sharing the signal line is sequentially selected by the scanning line. Only the light emitting element of the selected pixel is electrically connected to the signal line by the TFT formed in each pixel, and the light emitting elements of the other pixels are electrically disconnected from the signal line. Therefore, only the selected light-emitting element needs to be charged, so that variation in charging time is less likely to occur than in a passive matrix light-emitting device that does not use a conventional transistor, and luminance unevenness can be suppressed.

  In the present invention, the light-emitting device having the above structure is formed by a screen printing method, a printing method typified by an offset printing method, or a droplet discharge method. The droplet discharge method means a method of forming a predetermined pattern by discharging droplets containing a predetermined composition from the pores. By using the above printing method and droplet discharge method, various wirings typified by signal lines and scanning lines, TFT gate electrodes, light emitting element electrodes, etc. can be formed without using an exposure mask. become. However, in the light emitting device of the present invention, it is not necessary to use a printing method or a droplet discharge method for all the steps of forming a pattern. Therefore, for example, a printing method or a droplet discharge method is used in at least a part of the process, for example, a printing method or a droplet discharge method is used for forming a wiring and a gate electrode, and a lithography method is used for patterning a semiconductor film. What is necessary is just to use, and the lithography method may be used together. A mask used for patterning may be formed by a printing method or a droplet discharge method.

  Note that in the case of a normal active matrix light-emitting device, each TFT includes at least two TFTs: a TFT that controls input of a video signal to a pixel and a TFT that controls supply of current to the light-emitting element in accordance with the video signal. It has in the pixel. On the other hand, in the light emitting device of the present invention, the number of TFTs in a pixel can be reduced as compared with a normal active matrix light emitting device. Therefore, it is suitable for a printing method or a droplet discharge method in which it is difficult to make a pattern with higher definition than a lithography method.

  In the case of an active matrix light-emitting device, variations in characteristics such as threshold voltage and mobility of TFTs that control supply of current to the light-emitting elements are caused by variations in current supplied to the light-emitting elements, and thus between pixels. Causes variations in luminance. In the light emitting device of the present invention, the TFT formed in the pixel is used as a switching element, and the value of the current supplied to the light emitting element of each pixel is directly controlled in the drive circuit. Therefore, it is possible to prevent variation in luminance between pixels due to variation in TFT characteristics.

  Note that the light-emitting device of the present invention includes a panel in which a light-emitting element is sealed, and a module in which an IC or the like including a controller is mounted on the panel. Furthermore, in the process of manufacturing the light emitting device, the present invention may include in its category an element substrate corresponding to one mode before the light emitting element is completed. Specifically, the element substrate has means (TFT) for supplying current to the light emitting element in each of the plurality of pixels. The element substrate may be in a state where only the first electrode of the light-emitting element is formed, or after the conductive film to be the first electrode is formed and patterned to form the first electrode. It may be in the state before being applied, and all forms are applicable.

  In addition, in this specification, the light-emitting element includes, in its category, an element whose luminance is controlled by current or voltage. Specifically, the light-emitting element is used for OLED (Organic Light Emitting Diode) and FED (Field Emission Display). MIM type electron source elements (electron emitting elements) and the like are included.

  In the present invention, only the selected light-emitting element needs to be charged, so that variation in charging time is less likely to occur than in a passive matrix light-emitting device that does not use a conventional transistor, and luminance unevenness can be suppressed. In addition, the charging time until reaching light emission can be drastically shortened, and it is easy to take advantage of the electroluminescent material that the response speed is very high. Unlike a conventional passive matrix light-emitting device, an increase in charging time can be suppressed even when the number of pixels is increased, which is suitable for an increase in the size of a panel.

  In the present invention, the number of TFTs in a pixel can be reduced as compared with a normal active matrix light-emitting device. Therefore, in the case of the printing method or the droplet discharge method, the size of the pixel can be suppressed to some extent even if it is difficult to make the pattern highly precise than in the case of the lithography method.

  In the present invention, the TFT formed in the pixel is used as a switching element, and the value of the current supplied to the light emitting element of each pixel is directly controlled in the drive circuit. Therefore, it is possible to prevent variation in luminance between pixels due to variation in TFT characteristics.

  Further, by forming a pattern using a droplet discharge method or a printing method, a series of steps such as photoresist film formation, exposure, development, etching, and peeling performed by a lithography method can be simplified. Further, unlike the lithography method, the droplet discharge method and the printing method do not waste material that is removed by etching. Further, it is not necessary to use an expensive exposure mask, so that the cost for manufacturing the light-emitting device can be suppressed.

  Next, the structure of the light emitting device of the present invention will be described. FIG. 1A shows a top view of an element substrate before the light emitting element is sealed with a cover material. The element substrate 101 illustrated in FIG. 1A includes a pixel portion 102 and connection terminals 103 for supplying signals and power supply voltages to the pixel portion. A circuit diagram of the pixel portion 102 is shown in FIG.

  As shown in FIG. 1B, a plurality of pixels 104 are formed in the pixel portion 102. The pixel 104 includes a TFT 105 and a light emitting element 106. The light-emitting element 106 includes a first electrode, an electroluminescent layer formed on the first electrode, and a second electrode formed on the electroluminescent layer. One of the first electrode and the second electrode has an anode, and the other corresponds to a cathode. By applying a forward bias voltage between the first electrode and the second electrode and supplying a current, the light-emitting element 106 can emit light. Light emission obtained in the electroluminescent layer includes light emission (fluorescence) when returning from the singlet excited state to the ground state and light emission (phosphorescence) when returning from the triplet excited state to the ground state.

  Note that FIG. 1B illustrates a state where the second electrode is electrically separated between pixels, but the present invention is not limited to this structure. Although the first electrode is electrically separated between the pixels, the second electrode may be electrically connected. Note that in the conventional passive matrix light-emitting device, the second electrode must be formed separately for each column or row. However, in the present invention, it is not necessary to separate the second electrode. It has the merit that the manufacturing process of this electrode can be simplified. Further, in the case where pixels corresponding to the three primary colors of light are formed to display a color image, the second electrode may be electrically connected to each pixel corresponding to each color.

  The operation of each pixel 104 is controlled by a plurality of signal lines (here, S1 to S4) and a plurality of scanning lines (here, G1 to G3). Specifically, the TFT 105 of each pixel has its gate electrode connected to any one of the scanning lines G1 to G3, and either the source region or the drain region is connected to any one of the signal lines S1 to S4. The other is connected to the first electrode of the light emitting element 106. Note that FIG. 1B illustrates an example in which one TFT is formed for each pixel; however, a plurality of TFTs may be connected in series.

  Note that the TFT 105 may use an amorphous semiconductor, a semi-amorphous semiconductor (microcrystalline semiconductor), or an organic semiconductor as an active layer. In particular, a TFT using an amorphous semiconductor or a semi-amorphous semiconductor has an advantage that cost and yield can be increased because of fewer manufacturing steps than a TFT using a polycrystalline semiconductor. Further, since it is not necessary to provide a crystallization step after the formation of the semiconductor film, it is relatively easy to enlarge the panel. However, when an amorphous semiconductor or a semi-amorphous semiconductor is used as the active layer of the TFT 105, it is desirable that the n-type can secure a certain degree of mobility.

A semi-amorphous semiconductor is a film containing a semiconductor having an intermediate structure between amorphous and crystalline structures (including single crystal and polycrystal). This semi-amorphous semiconductor is a semiconductor having a third state which is stable in terms of free energy, and is a crystalline one having a short-range order and having a lattice strain, and having a grain size of 0.5 to 20 nm. It can be dispersed in a single crystal semiconductor. The semi-amorphous semiconductor has its Raman spectrum shifted to a lower wavenumber than 520 cm ⁻¹ , and diffraction peaks of (111) and (220), which are considered to be derived from the Si crystal lattice in X-ray diffraction, are observed. . Further, hydrogen or halogen is contained at least 1 atomic% or more as a neutralizing agent for dangling bonds. Here, for convenience, such a semiconductor is referred to as a semi-amorphous semiconductor (SAS). Further, by adding a rare gas element such as helium, argon, krypton, or neon to further promote lattice distortion, stability is improved and a favorable SAS can be obtained.

  Next, operation of the pixel portion 104 illustrated in FIG. 1B is described. First, the scanning lines G1 to G3 are selected in order. When a scan line is selected, the TFT 105 is turned on in one row of pixels having the scan line. In this state, when a current based on the video signal is supplied to the signal lines S1 to S4 in order or in parallel, the current is supplied to the light emitting element 106 through the TFT 105 which is turned on. The luminance of the light emitting element is controlled according to the value of the supplied current.

  Although not shown in FIG. 1, a protective circuit may be provided over the substrate 101. Since the discharge path can be secured by the protection circuit, the semiconductor element formed on the substrate 101 is deteriorated or broken down due to noise of the signal and the power supply voltage, or electric charge charged to the insulating film for some reason. Can be prevented. Specifically, in the case of FIG. 1A, a protective circuit can be connected to a wiring that electrically connects the connection terminal 103 and the pixel portion 101. Note that in FIG. 1A, a signal line driver circuit and a scan line driver circuit for controlling the operation of the pixel portion 102 are not formed over the substrate 101. In the case where the signal line driver circuit and the scan line driver circuit are formed over the substrate 101, in addition to the protection circuit, wiring that electrically connects the connection terminal 103 and the signal line driver circuit, and the connection terminal 103 and scanning. A wiring that electrically connects the line driver circuit, a wiring (signal line) that electrically connects the signal line driver circuit and the pixel portion 102, and a wiring that electrically connects the scanning line driver circuit and the pixel portion 102 A protection circuit can be connected to each connected wiring (scanning line).

  The video signal is assumed to be analog, but may be digital if the mobility of the TFT can be increased. When the video signal is digital, a time gray scale method in which a gray scale is displayed by controlling a time during which the light emitting element emits light may be used. A gradation method may be used.

  Next, a more specific structure and a manufacturing method of the light-emitting device of the present invention will be described with reference to FIGS.

  First, a substrate 200 on which TFTs and light emitting elements are formed is prepared. Specifically, for example, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, a ceramic substrate, or the like can be used as the substrate 200. Alternatively, a metal substrate including a SUS substrate or a semiconductor substrate with an insulating film formed on the surface thereof may be used. A substrate made of a synthetic resin having flexibility such as plastic generally tends to have a lower heat resistant temperature than the above substrate, but can be used as long as it can withstand the processing temperature in the manufacturing process. . The surface of the substrate 200 may be planarized by polishing such as a CMP method.

  Pretreatment for improving the adhesion of the conductive film or the insulating film formed by using the droplet discharge method or the printing method is performed on the surface of the substrate 200 described above. Specifically, as a method for improving the adhesion, for example, a method of attaching a metal or a metal compound capable of improving the adhesion of a conductive film or an insulating film to the surface of the substrate 200 by a catalytic action, a formed conductive A method of adhering an organic insulating film, metal, or metal compound having high adhesion to a film or an insulating film to the surface of the substrate 200, surface treatment by performing plasma treatment on the surface of the substrate 200 under atmospheric pressure or reduced pressure The method of performing is mentioned. Examples of the organic insulating film include an insulating film including a Si—O—Si bond (hereinafter, referred to as a siloxane insulating film) formed using polyimide or a siloxane material as a starting material. The siloxane insulating film may have at least one of fluorine, an alkyl group, and aromatic hydrocarbon in addition to hydrogen as a substituent.

  Note that in the case where the metal or the metal compound attached to the substrate 200 has conductivity, the sheet resistance is controlled to such an extent that normal operation of the semiconductor element is not hindered. Specifically, the average thickness of the conductive metal or metal compound is controlled to be, for example, 1 to 10 nm, or the metal or metal compound is partially or entirely insulated by oxidation. You can do it. Alternatively, the deposited metal or metal compound may be selectively removed by etching except for the region where the adhesion is desired to be improved. Alternatively, the metal or the metal compound may be selectively attached only to a specific region by using a droplet discharge method, a printing method, a sol-gel method, or the like, instead of attaching the metal or the metal compound to the entire surface of the substrate in advance. The metal or metal compound does not need to be a completely continuous film on the surface of the substrate 200, and may be dispersed to some extent.

In this embodiment mode, a photocatalyst such as ZnO or TiO ₂ that can improve adhesion by a photocatalytic reaction is attached to the surface of the substrate 200. Specifically, ZnO or TiO ₂ is dispersed in a solvent and distributed on the surface of the substrate 200, or a Zn compound or Ti compound is attached to the surface of the substrate 200 and then oxidized, or a sol-gel method. As a result, ZnO or TiO ₂ can be attached to the surface of the substrate 200 as a result.

  Next, the gate electrode 201 is formed on the surface of the substrate 200 that has been subjected to pretreatment for improving adhesion by using a droplet discharge method or various printing methods. Specifically, for the gate electrode, a conductive material including one or more metals such as Ag, Au, Cu, and Pd and a metal compound is used. Note that a conductive material having one or more metals, such as Cr, Mo, Ti, Ta, W, and Al, or a metal compound, can be used as long as aggregation can be suppressed by the dispersant. is there. A gate electrode in which a plurality of conductive films are stacked can be formed by performing film formation of a conductive material a plurality of times by a droplet discharge method or various printing methods.

  In the case of using a droplet discharge method, a conductive material dispersed in an organic or inorganic solvent is dropped from a nozzle and then dried or baked at room temperature. Specifically, in this embodiment, a solution in which Ag is dispersed in tetradecane is dropped, and the solvent is removed by baking at 200 ° C. to 300 ° C. for 1 min to 50 hr, whereby the gate electrode 201 is formed. In the case of using an organic solvent, by performing the baking in an oxygen atmosphere, the solvent can be efficiently removed and the resistance of the gate electrode 201 can be further reduced. Although not shown, a scanning line connected to the gate electrode 201 in this step can also be formed at the same time.

  When the droplet discharge method is used, the accuracy of the pattern depends on the discharge amount per dot of the droplet, the surface tension of the solution, the water repellency of the surface of the substrate 200 onto which the droplet is dropped. Therefore, it is desirable to optimize these conditions according to the accuracy of the desired pattern.

Here, the evaluation of the adhesiveness of Ag when titanium oxide is adhered to the surface of the substrate before Ag is ejected by the droplet ejection method will be described. First, a titanium film having a thickness of 1 to 5 nm was formed on a glass substrate by sputtering. The titanium film formed by baking at 230 ° C. was oxidized to form titanium oxide. At this time, when the sheet resistance of the film formed of titanium oxide was measured, it became lower than the lower limit of 1 × 10 ⁻⁶ Ω / □ that can be measured by the apparatus, so that it was confirmed that the insulation was sufficiently high. .

  Next, Ag was dropped onto 16 areas using a droplet discharge method, and then fired at 230 ° C. In addition, after baking, the strip-shaped Ag film | membrane formed in each area of 16 places became a dimension of length 1cm, width 200-300 micrometers, and thickness 400-500 nm.

  After the Kapton (R) tape was applied to the substrate on which the Ag film was formed, the adhesion of the Ag film was confirmed by removing the tape, and the Ag film was not peeled even after the tape was removed. It was. The substrate on which the Ag film was formed was immersed in a 0.5 wt% HF aqueous solution for 1 minute and then washed with running water to confirm the adhesion of the film. As a result, all the Ag film was not peeled off and was deposited on the substrate. It remained. The same result was obtained when titanium oxide was adhered to the surface of the substrate by spreading a solution in which the titanium oxide film was dispersed in the solvent on the surface of the substrate. By the way, when using a bare glass substrate, a glass substrate with a CMP polished surface, a glass substrate on which an amorphous silicon film, a silicon nitride film or a silicon oxide film is formed, there are some differences, but there are Only about this amount of Ag film remained. Therefore, it is considered that high adhesion is obtained by titanium oxide.

  Next, a gate insulating film 202 is formed so as to cover the gate electrode 201. As the gate insulating film 202, for example, an insulating film such as silicon oxide, silicon nitride, or silicon nitride oxide can be used. As the gate insulating film 202, a single-layer insulating film may be used, or a plurality of insulating films may be stacked. In this embodiment, an insulating film in which silicon nitride, silicon oxide, and silicon nitride are sequentially stacked is used as the gate insulating film 202. As a film formation method, a plasma CVD method, a sputtering method, or the like can be used. In order to form a dense insulating film capable of suppressing gate leakage current at a low deposition temperature, a rare gas element such as argon is preferably contained in the reaction gas and mixed into the formed insulating film. Aluminum nitride can be used for the gate insulating film 202. Aluminum nitride has a relatively high thermal conductivity and can efficiently dissipate heat generated in the TFT.

  Next, as illustrated in FIG. 2B, the first electrode 203 included in the light-emitting element is formed over the gate insulating film 202. Note that in this embodiment mode, the first electrode 203 corresponds to an anode and the second electrode 217 formed later corresponds to a cathode; however, the present invention is not limited to this structure. The first electrode 203 may correspond to a cathode, and the second electrode 217 may correspond to an anode.

  For the anode, other light-transmitting oxide conductive materials such as indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), and gallium-added zinc oxide (GZO) can be used. . Indium tin oxide containing ITO and silicon oxide (hereinafter referred to as ITSO) or indium oxide containing silicon oxide mixed with 2 to 20% zinc oxide (ZnO) may be used. In addition to the light-transmitting oxide conductive material as an anode, in addition to a single layer film made of, for example, one or more of TiN, ZrN, Ti, W, Ni, Pt, Cr, Ag, Al, etc., titanium nitride and A stack of a film containing aluminum as its main component, a three-layer structure of a titanium nitride film, a film containing aluminum as its main component, and a titanium nitride film can be used. However, when light is extracted from the anode side with a material other than the light-transmitting oxide conductive material, the light-transmitting oxide film is formed to have a film thickness that allows light to pass (preferably, about 5 nm to 30 nm).

  In this embodiment mode, ITSO is used as the first electrode 203 corresponding to the anode. Note that the first electrode 203 can be formed by a sputtering method, a droplet discharge method, or a printing method. In the case of using a droplet discharge method or a printing method, the first electrode 203 can be formed without using a mask. Even when the sputtering method is used, by forming a resist used in the lithography method by a droplet discharge method or a printing method, it is not necessary to separately prepare an exposure mask, which leads to cost reduction.

  Note that the first electrode 203 may be polished by polishing with a CMP method or a polyvinyl alcohol-based porous body so that the surface thereof is planarized. Further, after polishing using the CMP method, the surface of the anode may be subjected to ultraviolet irradiation, oxygen plasma treatment, or the like.

  Next, as shown in FIG. 2C, a first semiconductor film 204 is formed. The first semiconductor film 204 can be formed using an amorphous semiconductor or a semi-amorphous semiconductor (SAS). In this embodiment, a semi-amorphous semiconductor is used as the first semiconductor film 204. A semi-amorphous semiconductor has higher crystallinity and higher mobility than an amorphous semiconductor and can be formed without increasing the number of steps for crystallization unlike a polycrystalline semiconductor.

An amorphous semiconductor can be obtained by glow discharge decomposition of a silicide gas. Typical silicide gases include SiH ₄ and Si ₂ H ₆ . This silicide gas may be diluted with hydrogen, hydrogen and helium.

SAS can also be obtained by glow discharge decomposition of silicide gas. A typical silicide gas is SiH ₄ , and in addition, Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , SiF _{4 and the} like can be used. In addition, it is easy to form a SAS by diluting and using this silicide gas with hydrogen or a gas obtained by adding one or more kinds of rare gas elements selected from helium, argon, krypton, and neon to hydrogen. It can be. It is preferable to dilute the silicide gas at a dilution rate in the range of 2 to 1000 times. Furthermore, a carbide gas such as CH ₄ or C ₂ H ₆ , a germanium gas such as GeH ₄ or GeF ₄ , F ₂ or the like is mixed in the silicide gas, so that the energy bandwidth is 1.5-2. You may adjust to 4 eV or 0.9-1.1 eV. A TFT using SAS as the first semiconductor film can obtain a mobility of 1 to 10 cm ² / Vsec or more.

  Alternatively, the first semiconductor film may be formed by stacking a plurality of SAS formed of different gases. For example, among the various gases described above, a first semiconductor film is formed by stacking a SAS formed using a gas containing a fluorine atom and a SAS formed using a gas containing a hydrogen atom. Can do.

Of course, the reaction of the coating by glow discharge decomposition is performed under reduced pressure, but the pressure may be in the range of about 0.1 Pa to 133 Pa. The power for forming the glow discharge may be high frequency power of 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz. The pressure is in the range of approximately 0.1 Pa to 133 Pa, and the power supply frequency is 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz. The substrate heating temperature may be 300 ° C. or less, preferably 100 to 250 ° C. As an impurity element in the film, impurities of atmospheric components such as oxygen, nitrogen, and carbon are desirably 1 × 10 ²⁰ atoms / cm ³ or less, and in particular, the oxygen concentration is preferably 5 × 10 ¹⁹ atoms / cm ³ or less. Is 1 × 10 ¹⁹ atoms / cm ³ or less.

Note that in the case where a semiconductor film is formed using Si ₂ H ₆ and GeF ₄ or F ₂ , crystals grow from a side closer to the substrate of the semiconductor film, so that the crystallinity of the semiconductor film becomes closer to the side closer to the substrate. high. Therefore, in the case of a bottom-gate TFT whose gate electrode is closer to the substrate than the first semiconductor film, a region having high crystallinity on the side close to the substrate in the first semiconductor film can be used as a channel formation region. Suitable for, can increase the mobility more.

Further, when a semiconductor film is formed using SiH ₄ and H ₂ , larger crystal grains can be obtained on the side closer to the surface of the semiconductor film. Therefore, in the case of a top-gate TFT in which the first semiconductor film is closer to the substrate than the gate electrode, a region having high crystallinity on the side far from the substrate in the first semiconductor film can be used as a channel formation region. Suitable for, can increase the mobility more.

In addition, SAS shows a weak n-type conductivity when impurities intended for valence electron control are not intentionally added. This is because oxygen is easily mixed into the semiconductor film because glow discharge with higher power is performed than when an amorphous semiconductor is formed. Therefore, the threshold value can be controlled by adding an impurity imparting p-type to the first semiconductor film provided with the channel formation region of the TFT at the same time as or after the film formation. It becomes possible. The impurity imparting p-type is typically boron, and an impurity gas such as B ₂ H ₆ or BF ₃ may be mixed in the silicide gas at a rate of 1 ppm to 1000 ppm. For example, when boron is used as an impurity imparting p-type conductivity, the boron concentration is preferably 1 × 10 ^{14 to} 6 × 10 ¹⁶ atoms / cm ³ .

  Next, a protective film 205 is formed over the first semiconductor film 204 so as to overlap with a portion to be a channel formation region in the first semiconductor film 204. The protective film 205 may be formed using a droplet discharge method or a printing method, or may be formed using a CVD method, a sputtering method, or the like. As the protective film 205, an inorganic insulating film such as silicon oxide, silicon nitride, or silicon nitride oxide, a siloxane-based insulating film, or the like can be used. Alternatively, these films may be stacked and used as the protective film 205. In this embodiment mode, silicon nitride formed by a plasma CVD method and a siloxane-based insulating film formed by a droplet discharge method are stacked and used as the protective film 205. In this case, patterning of silicon nitride can be performed using a siloxane insulating film formed by a droplet discharge method as a mask.

  Next, as shown in FIG. 2D, the first semiconductor film 204 is patterned. For patterning the first semiconductor film 204, a lithography method may be used. A resist formed by a droplet discharge method or a printing method may be used as a mask. In the latter case, it is not necessary to prepare a mask for exposure separately, which leads to cost reduction. In this embodiment mode, an example of patterning using a resist 206 formed by a droplet discharge method is shown. Note that the resist 206 can be formed using an organic resin such as polyimide or acrylic. Then, a patterned first semiconductor film 207 is formed by dry etching using the resist 206.

Next, as shown in FIG. 3A, a second semiconductor film 208 is formed so as to cover the patterned first semiconductor film 207. An impurity imparting one conductivity type is added to the second semiconductor film 208 in advance. In the case of forming an n-channel TFT, an impurity imparting n-type conductivity, for example, phosphorus may be added to the second semiconductor film 208. Specifically, an impurity gas such as PH ₃ may be added to a silicide gas to form the second semiconductor film 208. The second semiconductor film 208 having one conductivity type can be formed using a semi-amorphous semiconductor or an amorphous semiconductor over the first semiconductor film 204.

  Note that in this embodiment mode, the second semiconductor film 208 is formed in contact with the first semiconductor film 207; however, the present invention is not limited to this structure. A third semiconductor film functioning as an LDD region may be formed between the first semiconductor film 207 and the second semiconductor film 208. In this case, the third semiconductor film is formed using a semi-amorphous semiconductor or an amorphous semiconductor. The third semiconductor film originally exhibits a weak n-type conductivity type without intentionally adding an impurity for imparting the conductivity type. Therefore, the third semiconductor film can be used as an LDD region with or without an impurity for imparting conductivity type.

  Next, as illustrated in FIG. 3B, wirings 209 and 210 are formed by a droplet discharge method or a printing method, and the second semiconductor 208 is etched using the wirings 209 and 210 as a mask. Etching of the second semiconductor 208 can be performed by dry etching in a vacuum atmosphere or an atmospheric pressure atmosphere. By the etching, two second semiconductors 211 and 212 functioning as a source region or a drain region are formed from the second semiconductor 208, and a part of the first electrode 203 is exposed. When the second semiconductor 208 is etched, the protective film 205 can prevent the first semiconductor film 207 from being over-etched.

  The wirings 209 and 210 can be formed in a manner similar to that of the gate electrode 201. Specifically, a conductive material including one or more metals such as Ag, Au, Cu, and Pd and a metal compound is used. In the case of using a droplet discharge method, a conductive material dispersed in an organic or inorganic solvent is dropped from a nozzle and then dried or baked at room temperature. A conductive material having one or more metals such as Cr, Mo, Ti, Ta, W, Al, or a metal compound can be used as long as aggregation can be suppressed by the dispersant and the dispersion can be dispersed in the solution. Baking may be performed in an oxygen atmosphere to reduce the resistance of the wirings 209 and 210. The wirings 209 and 210 in which a plurality of conductive films are stacked can also be formed by performing conductive film formation a plurality of times by a droplet discharge method or various printing methods.

FIG. 3C illustrates a top view of the light-emitting device illustrated in FIG. FIG. 3B corresponds to a cross-sectional view taken along a line AA ′ in FIG. Reference numeral 213 corresponds to a TFT for controlling current supply to a light emitting element 218 to be formed later. The wiring 209 functions as a signal line. The wiring 210 has a function of electrically connecting the TFT 213 and the light emitting element 218. Further, the gate electrode 201 is electrically connected to the scanning line 214.

Next, as illustrated in FIG. 4A, a partition wall 215 is formed so as to cover end portions of the TFT 213 and the first electrode 203. The partition wall 215 can be formed using an organic resin film, an inorganic insulating film, or a siloxane-based insulating film. For example, acrylic resin, polyimide, polyamide, or the like can be used for the organic resin film, and silicon oxide, silicon nitride oxide, or the like can be used for the inorganic insulating film. In particular, a photosensitive organic resin film is used for the partition wall 215, the opening 220 is formed on the first electrode 203, and the sidewall of the opening 220 is formed to be an inclined surface formed with a continuous curvature. Thus, connection between the first electrode 203 and the second electrode 217 formed later can be prevented. At this time, the mask can be formed by a droplet discharge method or a printing method. In addition, the partition wall 215 itself can be formed by a droplet discharge method or a printing method. Note that the partition wall 215 has an opening 220. In FIG. 4 (B), the light-emitting device shown in FIG. 4 (A), a top view. 4 (A) is a cross-sectional view taken along line A-A 'in FIG. 4 (B). A part of the first electrode 203 is exposed in the opening 220.

Next, before the electroluminescent layer 216 is formed, in order to remove moisture, oxygen, and the like adsorbed on the partition wall 215 and the first electrode 203, heat treatment is performed in an air atmosphere or heat treatment (vacuum baking) in a vacuum atmosphere. May be performed. Specifically, heat treatment is performed in a vacuum atmosphere at a substrate temperature of 200 ° C. to 450 ° C., preferably 250 to 300 ° C., for about 0.5 to 20 hours. It is desirably 3 × 10 ⁻⁷ Torr or less, and if possible, 3 × 10 ⁻⁸ Torr or less is most desirable. In the case where an electroluminescent layer is formed after heat treatment in a vacuum atmosphere, reliability can be further improved by placing the substrate in a vacuum atmosphere until just before the electroluminescent layer is formed. it can. The first electrode 203 may be irradiated with ultraviolet rays before or after vacuum baking.

  Note that in this embodiment mode, the insulating film formed of silicon nitride in the gate insulating film 202 is in contact with the first electrode 203 formed of ITSO. As described above, the first electrode or the second electrode of the light-emitting element is formed using the light-transmitting oxide conductive material such as ITSO and the conductive film including silicon oxide so as to be in contact with the insulating film including silicon nitride or silicon nitride oxide. By forming this electrode, the luminance of the light-emitting element can be increased as compared with any combination of the materials described above. In this case, the above-described vacuum baking is particularly effective because moisture easily adheres to silicon oxide contained in the first electrode 203.

  Then, an electroluminescent layer 216 is formed so as to be in contact with the first electrode 203 in the opening 220 of the partition wall 215. The electroluminescent layer 216 may be composed of a single layer or a plurality of layers stacked. In the case of a plurality of layers, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are stacked in this order on the first electrode 203 corresponding to the anode. Note that in the case where the first electrode 203 corresponds to a cathode, the electroluminescent layer 216 is formed by stacking an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer, and a hole injection layer in this order.

  Note that when a monochrome image is displayed or when a color image is displayed using a white light emitting element and a color filter, the structure of the electroluminescent layer 216 is the same in all pixels. In the case where a color image is displayed using three light emitting elements that emit light of three primary colors, the electroluminescent layer 216 may be applied separately by changing the material, the layer to be stacked, or the film thickness for each corresponding color. When the electroluminescent layer is separately applied, the droplet discharge method is very effective because there is no waste of material and the process can be simplified. Note that the color may be a full color using a mixed color or an area color in which a plurality of pixels having a single hue are arranged for each specific area.

  Note that the color filter may include a colored layer that can transmit light in a specific wavelength region and, in some cases, a shielding film that can shield visible light in addition to the colored layer. The color filter may be formed on a cover material for sealing the light emitting element or may be formed on an element substrate. In any case, the colored layer or the shielding film can be formed using a printing method or a droplet discharge method.

  The electroluminescent layer 216 can be formed by a droplet discharge method using any of a high molecular weight organic compound, a medium molecular weight organic compound, a low molecular weight organic compound, and an inorganic compound. Medium molecular organic compounds, low molecular organic compounds, and inorganic compounds may be formed by vapor deposition.

  Then, a second electrode 217 is formed so as to cover the electroluminescent layer 216. In this embodiment mode, the second electrode 217 corresponds to a cathode. As a method for manufacturing the second electrode 217, it is preferable to use a vapor deposition method, a sputtering method, a droplet discharge method, or the like according to the material.

As the cathode, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a low work function can be used. Specifically, alkali metals such as Li and Cs, and alkaline earth metals such as Mg, Ca, and Sr, alloys containing these (Mg: Ag, Al: Li, Mg: In, etc.), and compounds thereof ( In addition to CaF ₂ and CaN, rare earth metals such as Yb and Er can be used. When an electron injection layer is provided, other conductive layers such as Al can be used. When light is extracted from the cathode side, other light-transmitting oxide conductive materials such as indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), and gallium-added zinc oxide (GZO) are used. It is possible to use. Indium tin oxide containing ITO and silicon oxide (hereinafter referred to as ITSO) or indium oxide containing silicon oxide mixed with 2 to 20% zinc oxide (ZnO) may be used. In the case of using a light-transmitting oxide conductive material, it is desirable to provide an electron injection layer in the electroluminescent layer 216. In addition, without using a light-transmitting oxide conductive material, light can be extracted from the cathode side by forming the cathode with a film thickness that allows light to pass therethrough (preferably, about 5 nm to 30 nm). In this case, a light-transmitting conductive layer may be formed using a light-transmitting oxide conductive material so as to be in contact with or under the cathode so as to suppress the sheet resistance of the cathode.

  In the opening 220 of the partition wall 215, the first electrode 203, the electroluminescent layer 216, and the second electrode 217 overlap with each other, so that the light-emitting element 218 is formed.

  Note that light can be extracted from the light-emitting element 218 from the first electrode 203 side, the second electrode 217 side, or both. Among the above three configurations, the material and film thickness of each of the anode and the cathode are selected in accordance with the target configuration.

  Note that a passivation film may be formed so as to cover the light-emitting element 218. As the passivation film, a film that hardly transmits a substance that causes the deterioration of the light-emitting element such as moisture or oxygen as compared with other insulating films is used. Typically, it is desirable to use, for example, a silicon nitride film formed by a DLC film, a carbon nitride film, an RF sputtering method, a CVD method, or the like. Further, for example, a film in which a carbon nitride film and silicon nitride are stacked, a film in which polystyrene is stacked, or the like may be used as the passivation film. It is also possible to use the above-mentioned film as a passivation film by laminating a film that is less permeable to substances such as moisture and oxygen and a film that is more permeable to substances such as moisture and oxygen but has lower internal stress than the film. It is. In the case of using silicon nitride, in order to form a dense passivation film at a low film formation temperature, a rare gas element such as argon is preferably included in the reaction gas and mixed into the passivation film.

  Actually, when the state shown in FIGS. 4A and 4B is completed, a protective film (laminate film, UV curable resin film, etc.) that is highly airtight and less degassed so as not to be exposed to the outside air. ) Or a cover material.

  Note that although a process for forming a pixel portion is described in this embodiment mode, a scan line driver circuit can be formed over the same substrate as the pixel portion when a semi-amorphous semiconductor is used as the first semiconductor film. . Alternatively, a pixel portion may be formed using a TFT using an amorphous semiconductor, and a separately formed driver circuit may be attached to the substrate on which the pixel portion is formed.

Note that in FIGS. 2 to 4, the first semiconductor film and the second semiconductor film are patterned in separate steps; however, the light-emitting device of the present invention is not limited to this manufacturing method. Next, an example in which the first semiconductor film and the second semiconductor film are patterned using the same mask will be described with reference to FIGS.

  First, according to the manufacturing method described above, the manufacturing process is similarly performed up to the state shown in FIG. Next, as shown in FIG. 5A, before the first semiconductor film 204 is patterned, a second semiconductor film 230 is formed. In the case of forming the third semiconductor film used as the LDD region, the first semiconductor film 204 is formed, then the third semiconductor film is formed, and then the second semiconductor film 230 is formed. Next, as shown in FIG. 5B, the first semiconductor film 204 and the second semiconductor film 230 are patterned using a resist 231 formed by a droplet discharge method or a printing method as a mask. In FIG. 5B, reference numerals 232 and 233 correspond to the first semiconductor film and the second semiconductor film after patterning, respectively.

  Next, as shown in FIG. 5C, wirings 234 and 235 are formed by a droplet discharge method or a printing method. Then, by using the wirings 234 and 235 as masks and further patterning the second semiconductor film 233, two second semiconductor films 236 and 237 functioning as a source region or a drain region are formed. After that, as in the manufacturing method illustrated in FIGS. 2 to 4, the partition wall 240, the electroluminescent layer 241, and the second electrode 242 can be formed.

  When the manufacturing method illustrated in FIGS. 5A to 5C is used, the first electrode 203 and the wiring 235 are in direct contact with each other, so that the contact resistance in the connection portion can be reduced.

  In the manufacturing method illustrated in FIGS. 2 to 4 and the manufacturing method illustrated in FIG. 5, the first electrode is formed before forming the second semiconductor film and the wiring in contact with the second semiconductor film. However, the present invention is not limited to this configuration. 6A, the first electrode is formed after the second semiconductor film and the wiring in contact with the second semiconductor film are formed in the manufacturing method illustrated in FIGS. FIG. 3 shows a cross-sectional view of a pixel.

  6A, reference numerals 601 and 602 correspond to second semiconductor films functioning as a source region or a drain region, and a wiring 603 is in contact with the second semiconductor film 601 so as to be in contact with the second semiconductor film 602. A wiring 604 is formed so as to be in contact with the top. Note that in FIG. 6A, the first semiconductor film 606 and the second semiconductor films 601 and 602 are formed by patterning using the same mask as in the case shown in FIGS. However, the present invention is not limited to this configuration, and may be separately patterned as in the case of FIG. In FIG. 6A, a first electrode 605 is formed so as to be in contact with the wiring 604. As shown in FIG. 6A, after the second semiconductor films 601 and 602 and the wirings 603 and 604 in contact with the second semiconductor films 601 and 602 are formed, the first electrode 605 is formed. Thus, the surface of the first electrode 605 can be prevented from being roughened by using dry etching when patterning the second semiconductor films 601 and 602.

  In FIGS. 2 to 4, 5, and 6A, the first electrode is formed over the gate insulating film, but the present invention is not limited to this structure. FIG. 6B is a cross-sectional view of the pixel in the case where an interlayer insulating film is formed so as to cover the TFT and the first electrode is formed over the interlayer insulating film. In FIG. 6B, a TFT 610 and wirings 611 and 612 connected to a source region or a drain region of the TFT 610 are covered with an interlayer insulating film 613, and a first electrode is formed over the interlayer insulating film 613. 614 is formed. The interlayer insulating film 613 can be formed using an organic resin film, an inorganic insulating film, or a siloxane-based insulating film. A material called a low dielectric constant material (low-k material) may be used for the interlayer insulating film 613. The first electrode 614 and the wiring 611 are electrically connected through a pillar 615 formed in the contact hole of the interlayer insulating film 613.

  In FIG. 6B, the pillar 615 is formed using a droplet discharge method before the interlayer insulating film 613 is formed. Specifically, a pillar 615 is formed by dropping a solution containing a conductive material at the same point and overlapping the droplets. As the conductive material used for the pillar 615, a light-transmitting oxide conductive material typified by ITO or ITSO can be used. After the pillar 615 is formed, an interlayer insulating film 613 is formed by a coating method such as a spin coat method, and then the surface of the interlayer insulating film 613 is etched to expose the pillar 615. Then, a first electrode 614 is formed over the interlayer insulating film 613 so as to be in contact with the pillar 615.

In FIG. 6B, the pillar 615 is formed before the interlayer insulating film 613 is formed; however, the pillar 615 may be formed after the interlayer insulating film 613 is formed. In this case, a contact hole is formed in the interlayer insulating film 613, and a pillar 615 is formed by dropping a solution containing a conductive material into the contact hole by a droplet discharge method. The contact hole can be formed by either dry etching or wet etching. Further, before forming the interlayer insulating film, an organic material having liquid repellency may be applied to a region where the contact hole is formed by a droplet discharge method or a printing method. In this case, the contact hole can be formed without etching by removing the liquid-repellent organic material after forming the interlayer insulating film. As an organic material having liquid repellency, polyvinyl alcohol (PVA), fluoroalkylsilane (FAS), or the like can be used. The organic material having liquid repellency can be removed by washing with water or dry etching using CF ₄ , O ₂ or the like.

The interlayer insulating film may be formed using a droplet discharge method. FIG. 6C is a cross-sectional view of a pixel in the case where an interlayer insulating film is formed using a droplet discharge method. In FIG. 6C, the TFT 620 is covered with a first interlayer insulating film 621, and the first interlayer insulating film 621 is formed by a droplet discharge method. A wiring 622 connected to the source region and the drain region of the TFT 620 does not completely overlap with the first interlayer insulating film 621 but is partially exposed. The first interlayer insulating film 624 is formed using a droplet discharge method in the same manner as the first interlayer insulating film 621, and the first electrode 623 is formed so as to cover the first interlayer insulating film 624. Is formed. A part of the wiring 622 that is exposed is in contact with the first electrode 623, and a second interlayer insulating film 625 is further formed so as to cover the contacted part.

  The second interlayer insulating film 625 has an opening in a region overlapping with the first interlayer insulating film 624, and is formed over the first electrode 623 and the second interlayer insulating film 625 in the opening. The electroluminescent layer 626 and the cathode 627 overlapped to form a light emitting element.

In FIGS. 2 to 6, a protective film is formed between the first semiconductor film and the second semiconductor film of the TFT. However, the present invention is not limited to this structure, and the case of FIGS. In this case, the protective film is not necessarily formed. FIG. 7A shows a cross-sectional view of a pixel in the case where a protective film is not formed. A TFT 701 illustrated in FIG. 7A includes a gate electrode 702 formed over a substrate 700, a gate insulating film 703 formed so as to cover the gate electrode 702, and a gate insulating film so as to overlap the gate electrode 702. A first semiconductor film 704 formed over the first semiconductor film 704; and second semiconductor films 705 and 706 in contact with the first semiconductor film 704. When the second semiconductor films 705 and 706 are formed by etching, a fluoride gas such as SF ₆ , NF ₃ , or CF ₄ is used as an etching gas. In this etching, since the etching selectivity with respect to the first semiconductor film 704 cannot be obtained, the processing time is appropriately adjusted. By this etching, the first semiconductor film 704 is partially exposed.

  In the case where the first semiconductor film 704 and the second semiconductor films 705 and 706 are patterned using the same mask without forming a protective film as in FIG. 7A, the gate insulating film 703, The semiconductor film 704 and the second semiconductor film 705 can be formed successively without being exposed to the air. In other words, each stacked interface can be formed without being contaminated by atmospheric components or contaminants floating in the atmosphere, so that variations in TFT characteristics can be reduced.

  In FIGS. 2 to 6 and FIG. 7A, the gate electrode is formed on the substrate side of the first semiconductor film; however, the present invention is not limited to this structure. FIG. 7B is a cross-sectional view of the pixel in the case where the first semiconductor film is formed on the substrate side with respect to the gate electrode. In FIG. 7B, wirings 712 and 713 are formed over a substrate 710, and second semiconductor films 714 and 715 are formed so as to be in contact with the wirings 712 and 713. A first semiconductor film 716 is formed so as to be in contact with the films 714 and 715. A gate insulating film 717 is formed over the first semiconductor film 716, and a gate electrode 718 is formed over the gate insulating film 717 so as to overlap with the first semiconductor film 716.

  Note that each of the TFTs shown in FIGS. 2 to 4, 5, 6, and 7 uses a second semiconductor film that functions as a source region or a drain region. It does not necessarily have to be formed. In this case, the wiring is directly connected to the first semiconductor film, and the wiring functions as a source region or a drain region. In particular, in the case of the TFT shown in FIG. 7B, a mask used for patterning for forming the second semiconductor films 714 and 715 becomes unnecessary, so that the number of steps can be significantly reduced.

  In this embodiment, a top view of a pixel in the case where the TFT layout is different from that in FIG.

  FIG. 8 shows a top view of the pixel of this embodiment. In FIG. 8, reference numeral 801 denotes a signal line, 802 denotes a scanning line, 803 denotes a TFT, and 804 denotes a first electrode included in the light emitting element. One of a source region or a drain region of the TFT 803 is electrically connected to the signal line 801, and the other is electrically connected to the first electrode 804 through a wiring 805. Although not shown, an electroluminescent layer and a second electrode are sequentially stacked on the first electrode 804, and reference numeral 805 denotes the first electrode 804, the electroluminescent layer, and the second electrode. The area where and overlap.

  In this embodiment, the first semiconductor film 806 included in the TFT 803 intersects with the scan line 802, and thus a part of the scan line 802 functions as a gate electrode. For this reason, when the scanning line is formed using the droplet discharge method, it is only necessary to scan the nozzle in one direction, so that the time required for drawing the scanning line can be shortened.

  Next, the structure of the light-emitting element will be described with reference to FIG. The element structure of the light emitting element in the present invention is schematically shown in FIG.

  9 includes a first electrode 501 formed over a substrate 500, an electroluminescent layer 502 formed over the first electrode 501, and a second electrode formed over the electroluminescent layer 502. An electrode 503. Note that actually, various layers, semiconductor elements, and the like are provided between the substrate 500 and the first electrode 501.

  In this embodiment, the case where the first electrode 501 is an anode and the second electrode is a cathode will be described; however, the first electrode 501 may be a cathode and the second electrode may be an anode. Since specific materials used for the anode and the cathode have already been described, a specific structure of the electroluminescent layer 502 will be described here.

  The electroluminescent layer 502 is composed of one or more layers. When composed of a plurality of layers, these layers can be classified into a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like from the viewpoint of carrier transport characteristics. Note that the boundaries between the layers are not necessarily clear, and there are cases where the materials constituting the layers are partially mixed and the interface is unclear. For each layer, an organic material or an inorganic material can be used. As the organic material, any of high molecular, medium molecular, and low molecular materials can be used. The medium molecular weight material corresponds to a low polymer having a number of repeating structural units (degree of polymerization) of about 2 to 20.

  The distinction between a hole injection layer and a hole transport layer is not necessarily strict, and these are the same in the sense that hole transportability (hole mobility) is a particularly important characteristic. For convenience, the hole injection layer is a layer in contact with the anode, and the layer in contact with the hole injection layer is referred to as a hole transport layer to be distinguished. The same applies to the electron transport layer and the electron injection layer. The layer in contact with the cathode is called an electron injection layer, and the layer in contact with the electron injection layer is called an electron transport layer. The light emitting layer may also serve as an electron transport layer, and is also referred to as a light emitting electron transport layer. FIG. 9 illustrates the case where the electroluminescent layer 502 includes the first to fifth layers 504 to 508. The first to fifth layers 504 to 508 are sequentially stacked from the first electrode 501 toward the second electrode 503.

Since the first layer 504 functions as a hole injection layer, it is preferable to use a material having a hole transporting property, a relatively low ionization potential, and a high hole injecting property. Broadly divided into metal oxides, low-molecular organic compounds, and high-molecular organic compounds. As the metal oxide, for example, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, or the like can be used. If low molecular weight organic compound, for example, starburst amine typified by m-MTDATA, copper phthalocyanine (abbreviation: Cu-Pc) in the metal phthalocyanine represented, phthalocyanine (abbreviation: H ₂ -Pc), _2, A 3-dioxyethylenethiophene derivative or the like can be used. A film in which a low molecular organic compound and the metal oxide are co-evaporated may be used. As a high molecular organic compound, for example, a polymer such as polyaniline (abbreviation: PAni), polyvinyl carbazole (abbreviation: PVK), or a polythiophene derivative can be used. Polyethylene dioxythiophene (abbreviation: PEDOT), which is one of polythiophene derivatives, doped with polystyrene sulfonic acid (abbreviation: PSS) may be used. Further, a benzoxazole derivative and any one or more materials of TCQn, FeCl ₃ , C _60, or F ₄ TCNQ may be used in combination.

  Since the second layer 505 functions as a hole transport layer, it is desirable to use a known material having high hole transportability and low crystallinity. Specifically, an aromatic amine-based compound (that is, a compound having a benzene ring-nitrogen bond) is suitable, for example, 4,4-bis [N- (3-methylphenyl) -N-phenylamino]. Biphenyl (TPD) and its derivative 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] biphenyl (α-NPD) are examples. Starburst type aromatic amine compounds such as 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (TDATA) and MTDATA can also be used. Alternatively, 4,4 ′, 4 ″ -tris (N-carbazolyl) triphenylamine (abbreviation: TCTA) may be used. As the polymer material, poly (vinyl carbazole) or the like exhibiting good hole transportability can be used.

Since the third layer 506 functions as a light emitting layer, it is preferable to use a material having a large ionization potential and a large band gap. Specifically, for example, tris (8-quinolinolato) aluminum (Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (Almq ₃ ), bis (10-hydroxybenzo [η] -quinolinato) beryllium (BeBq) ₂ ), bis (2-methyl-8-quinolinolato)-(4-hydroxy-biphenylyl) -aluminum (BAlq), bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (Zn (BOX) ₂ ), Bis [2- (2-hydroxyphenyl) -benzothiazolate] zinc (Zn (BTZ) ₂ ), and the like. Various fluorescent dyes (coumarin derivatives, quinacridone derivatives, rubrene, 4,4-dicyanomethylene, 1-pyrone derivatives, stilbene derivatives, various condensed aromatic compounds, etc.) can also be used. Phosphorescent materials such as platinum octaethylporphyrin complex, tris (phenylpyridine) iridium complex, tris (benzylideneacetonato) phenanthrene europium complex can also be used.

  As the host material used for the third layer 506, a hole transport material or an electron transport material typified by the above example can be used. Alternatively, a bipolar material such as 4,4′-N, N′-dicarbazolylbiphenyl (abbreviation: CBP) can be used.

Since the fourth layer 507 functions as an electron transporting layer, a material having a high electron transporting property is preferably used. Specifically, a metal complex having a quinoline skeleton or a benzoquinoline skeleton represented by Alq ₃ or a mixed ligand complex thereof can be used. Specifically, metal complexes such as Alq ₃ , Almq ₃ , BeBq ₂ , BAlq, Zn (BOX) ₂ , and Zn (BTZ) ₂ can be given. In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (PBD), 1,3-bis [5- (p Oxadiazole derivatives such as -tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5 -(4-biphenylyl) -1,2,4-triazole (TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2, Triazole derivatives such as 4-triazole (p-EtTAZ); imidazole derivatives such as TPBI; It can be used derivatives.

Since the fifth layer 508 functions as an electron injection layer, it is preferable to use a material having a high electron injection property. Specifically, an ultra-thin film of an insulator such as an alkali metal halide such as LiF or CsF, an alkaline earth halide such as CaF ₂ , or an alkali metal oxide such as Li ₂ O is often used. In addition, alkali metal complexes such as lithium acetylacetonate (abbreviation: Li (acac) and 8-quinolinolato-lithium (abbreviation: Liq) are also effective. Molybdenum oxide (MoOx), vanadium oxide (VOx), A metal oxide such as ruthenium oxide (RuOx) or tungsten oxide (WOx) or a benzoxazole derivative, and one or more materials of alkali metal, alkaline earth metal, or transition metal may be included. Further, titanium oxide may be used.

  In the light-emitting element having the above structure, light is applied from the third layer 506 by applying a voltage between the first electrode 501 and the second electrode 503 and supplying a forward bias current to the electroluminescent layer 502. And the light can be extracted from the first electrode 501 side and the second electrode 503 side. Note that the electroluminescent layer 502 is not necessarily required to have all of the first to fifth layers. In the present invention, it is only necessary to include at least the third layer 506 functioning as a light emitting layer. Further, light emission is not necessarily obtained only from the third layer 506, and light emission may be obtained from layers other than the third layer 506 depending on the combination of materials used for the first to fifth layers. Further, a hole blocking layer may be provided between the third layer 506 and the fourth layer 507.

  Note that depending on the color, the phosphorescent material can have a lower driving voltage and higher reliability than the fluorescent material. Therefore, when full-color display is performed using light-emitting elements corresponding to the three primary colors, a combination of a light-emitting element using a fluorescent material and a light-emitting element using a phosphorescent material can reduce the deterioration of the light-emitting element of each color. You may make it arrange | equalize a degree.

  FIG. 9 illustrates the case where the first electrode 501 is a cathode and the second electrode 503 is a cathode. However, when the first electrode 501 is a cathode and the second electrode 503 is an anode, The fifth layers 504 to 508 are stacked in reverse. Specifically, a fifth layer 508, a fourth layer 507, a third layer 506, a second layer 505, and a first layer 504 are sequentially stacked over the first electrode 501.

  In this embodiment, a driver circuit used for the light-emitting device of the present invention will be described. FIG. 10 shows a block diagram of the light emitting device of this embodiment. A light-emitting device illustrated in FIG. 10 includes a pixel portion 1101 having a plurality of pixels each including a light-emitting element, a scanning line driver circuit 1102 that selects each pixel, and a signal line driver that controls input of a video signal to the selected pixel. Circuit 1103.

  In FIG. 10, the signal line driver circuit 1103 includes a shift register 1104, a latch circuit 1105, and a V / I conversion circuit 1106. A clock signal (CLK), a start pulse signal (SP), and a switching signal (L / R) are input to the shift register 1104. When the clock signal (CLK) and the start pulse signal (SP) are input, a timing signal is generated in the shift register 1104 and input to the latch circuit 1105. Further, the order of appearance of the pulses of the timing signal is switched by the switching signal (L / R).

  The generated timing signals are sequentially input to the latch circuit 1105. When a timing signal is input to the latch circuit 1105, video signals are sequentially written and held in the latch circuit 1105 in synchronization with the timing signal pulse. In this embodiment, video signals are sequentially written in the latch circuit 1105, but the present invention is not limited to this configuration. A plurality of stages of latch circuits 1105 may be divided into several groups, and so-called divided driving may be performed in which video signals are input in parallel for each group. Note that the number of groups at this time is called the number of divisions. For example, when the latches are divided into groups for every four stages, it is said that the driving is divided into four.

  The video signal written to the latch circuit 1105 is input to the V / I conversion circuit 106. The V / I conversion circuit 106 supplies a current having a value corresponding to the potential of the input video signal to the pixel portion 1101 through the signal line.

  Next, the structure of the scan line driver circuit 1102 is described. The scan line driver circuit 1102 includes a shift register 1107 and a buffer 1108. In some cases, a level shifter may be provided. In the scan line driver circuit 1102, when the clock CLK and the start pulse signal SP are input to the shift register 1107, a selection signal is generated. The generated selection signal is buffered and amplified in the buffer 1108 and supplied to the corresponding scanning line. The gate of the transistor of the pixel for one line is connected to the scanning line. Since the transistors of the pixels for one line must be turned on all at once, a buffer 1108 that can flow a large current is used.

  Instead of the shift registers 1104 and 1107, another circuit capable of selecting a signal line such as a decoder circuit may be used.

  In the light-emitting device illustrated in FIG. 10, the signal line driver circuit 1103 and the scan line driver circuit 1102 can be formed using an IC and mounted on a substrate over which the pixel portion 1101 is formed. Note that the present invention is not limited to this, and either the scan line driver circuit 1102 or the signal line driver circuit 1103 may be formed over the same substrate as the pixel portion 1101 and the other may be formed using an IC. Alternatively, only part of the signal line driver circuit 1103 and part of the scan line driver circuit 1102 may be formed using an IC.

  Note that not only a driver circuit for controlling the operation of the display element, typified by a signal line driver circuit and a scanning line driver circuit, but also a controller, a CPU, a memory, and the like are formed using an IC, and the IC is formed with a pixel portion. It can also take the form of being mounted on a substrate.

  In this embodiment, an embodiment of a method for connecting a light emitting device and an IC will be described.

  FIGS. 11A and 11B show how a chip-like IC (IC chip) is mounted on an element substrate over which a pixel portion is formed. In FIG. 11A, a pixel portion 6002 and a scan line driver circuit 6003 are formed over a substrate 6001. A signal line driver circuit formed in the IC chip 6004 is mounted on the substrate 6001. Specifically, a signal line driver circuit formed in the IC chip 6004 is attached to the substrate 6001 and electrically connected to the pixel portion 6002. Reference numeral 6005 denotes an FPC, and a power supply potential, various signals, and the like are supplied to the pixel portion 6002, the scan line driver circuit 6003, and the signal line driver circuit formed in the IC chip 6004 through the FPC 6005, respectively.

  In FIG. 11B, a pixel portion 6102 and a scan line driver circuit 6103 are formed over a substrate 6101. The signal line driver circuit formed on the IC chip 6104 is further mounted on the FPC 6105 mounted on the substrate 6101. A power supply potential, various signals, and the like are supplied to the pixel portion 6102, the scan line driver circuit 6103, and the signal line driver circuit formed in the IC chip 6104 through the FPC 6105.

  The IC chip mounting method is not particularly limited, and a known COG method, wire bonding method, TAB method, or the like can be used. Further, the position where the IC chip is mounted is not limited to the position shown in FIG. 11 as long as electrical connection is possible. 11 shows an example in which only the signal line driver circuit is formed using an IC chip, the scanning line driver circuit may be formed using an IC chip, and a controller, a CPU, a memory, and the like may be formed using an IC chip. You may make it implement. Further, instead of forming the entire signal line driver circuit and the scanning line driver circuit with an IC chip, only a part of the circuits constituting each driver circuit may be formed with an IC chip.

  Note that by separately forming and mounting an integrated circuit such as a driver circuit using an IC chip, the yield can be increased as compared with the case where all the circuits are formed over the same substrate as the pixel portion. The process can be easily optimized according to the characteristics.

  In this example, the appearance of a panel corresponding to one embodiment of the light-emitting device of the present invention will be described with reference to FIG. FIG. 12 is a top view of a panel in which a TFT and a light-emitting element formed over an element substrate are sealed with a sealing material between the cover material and FIG. 12B is a plan view of FIG. This corresponds to a cross-sectional view taken along the line AA ′.

  A sealant 4005 is provided so as to surround the pixel portion 4002 provided over the element substrate 4001 and the scan line driver circuit 4004. A cover member 4006 is provided over the pixel portion 4002 and the scan line driver circuit 4004. Therefore, the pixel portion 4002 and the scan line driver circuit 4004 are sealed together with the filler 4007 by the element substrate 4001, the sealant 4005, and the cover member 4006. In addition, an IC in which the signal line driver circuit 4003 is formed is mounted in a region different from the region surrounded by the sealant 4005 over the element substrate 4001.

  The pixel portion 4002 provided over the element substrate 4001 and the scan line driver circuit 4004 each include a plurality of TFTs. FIG. 12B illustrates a TFT 4010 included in the pixel portion 4002. Reference numeral 4011 corresponds to a light emitting element, and is electrically connected to the source region or the drain region of the TFT 4010.

  In addition, a variety of signals and potentials are supplied to the signal line driver circuit 4003 which is formed separately, the scan line driver circuit 4004, or the pixel portion 4002, although they are not shown in the cross-sectional view in FIG. And 4015 through a connection terminal 4016. Each of the connection terminal 4016 and the lead wirings 4014 and 4015 can be formed by a droplet discharge method or a printing method.

  The connection terminal 4016 is electrically connected to a terminal included in the FPC 4018 through an anisotropic conductive film 4019.

  Note that as the element substrate 4001 and the cover material 4006, glass, metal (typically stainless steel), ceramics, or plastic can be used. As the plastic, an FRP (Fiberglass-Reinforced Plastics) plate, a PVF (polyvinyl fluoride) film, a mylar film, a polyester film, or an acrylic resin film can be used. A sheet having a structure in which an aluminum foil is sandwiched between PVF films or mylar films can also be used.

  However, the cover material must be transparent on the substrate located in the light extraction direction from the light emitting element 4011. In that case, a light-transmitting material such as a glass plate, a plastic plate, a polyester film, or an acrylic film is used.

  As the filler 4007, in addition to an inert gas such as nitrogen or argon, an ultraviolet curable resin or a thermosetting resin can be used. PVC (polyvinyl chloride), acrylic, polyimide, epoxy resin, silicon resin, PVB (Polyvinyl butyral) or EVA (ethylene vinyl acetate) can be used. In this example, nitrogen was used as the filler.

  Further, in order to expose the filler 4007 to a hygroscopic substance (preferably barium oxide) or a substance capable of adsorbing oxygen, a hygroscopic substance or oxygen is added between the cover material 4006 and the element substrate 4001 together with the filler 4007. A substance capable of adsorbing may be provided. By providing a hygroscopic substance or a substance that can adsorb oxygen, deterioration of the light-emitting element 4011 can be suppressed.

  Note that FIG. 12 illustrates an example in which the signal line driver circuit 4003 is separately formed and mounted on the element substrate 4001, but this embodiment is not limited to this structure. The scan line driver circuit may be separately formed and then mounted, or only part of the signal line driver circuit or part of the scan line driver circuit may be separately formed and then mounted.

  This embodiment can be implemented in combination with the structure described in other embodiments.

  In this embodiment, a structure of a TFT formed in a pixel in the light emitting device of the present invention will be described.

  FIG. 14 is a cross-sectional view of the pixel of this example. In FIG. 14, 1401 corresponds to a TFT for controlling the input of a video signal to a pixel, and 1402 corresponds to a light emitting element. The TFT 1401 and the light emitting element 1402 are sealed together with the filler 1406 between the substrate 1403 and the cover material 1404 by a sealant 1405.

  The TFT 1401 includes gate electrodes 1407 and 1408, a gate insulating film 1409 formed on the gate electrodes 1407 and 1408, a first semiconductor film 1410 formed on the gate insulating film 1409, and the first semiconductor film 1410. The second semiconductor films 1411 to 1413 and the wirings 1414 to 1416 connected to the second semiconductor films 1411 to 1413, respectively. The wiring 1414 corresponds to a signal line, and the wiring 1416 is connected to the light-emitting element 1402.

  The TFT 1401 has a so-called multi-gate structure in which a plurality of TFTs connected in series and connected to a gate electrode share a first semiconductor film. With the multi-gate structure, the off-state current of the TFT 1401 can be reduced. Specifically, in FIG. 14, the TFT 1401 has a configuration in which two TFTs are connected in series, but a multi-gate structure in which three or more TFTs are connected in series and a gate electrode is connected. It may be.

  In this embodiment, the case where the TFT shown in FIG. 5 has a multi-gate structure is shown; however, the present invention is not limited to this structure. For example, the TFT shown in FIGS. 2 to 4, the TFT shown in FIG. 6, and the TFT shown in FIG. 7 may similarly have a multi-gate structure.

  Electronic devices that can use the light emitting device of the present invention include a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio, audio component, etc.), a notebook type personal computer, a game A device, a portable information terminal (mobile computer, mobile phone, portable game machine, electronic book or the like), and an image playback device (typically a DVD: Digital Versatile Disc) or the like provided with a recording medium. And the like). In particular, the light-emitting device of the present invention can suppress an increase in charging time and a cost per area even when the number of pixels is increased. Therefore, the light-emitting device of the present invention is particularly suitable for an electronic device in which a relatively large panel is used. Specific examples of these electronic devices are shown in FIGS.

  FIG. 13A illustrates a display device, which includes a housing 2001, a display portion 2002, a speaker portion 2003, and the like. The light emitting device of the present invention can be used for the display portion 2002. Since the light-emitting device is a self-luminous type, a backlight is not necessary and a display portion thinner than a liquid crystal display can be obtained. The display devices include all information display devices for personal computers, TV broadcast reception, advertisement display, and the like. Note that in the case where a light-emitting device is used for the display device, a polarizing plate is provided in order to prevent external light from being reflected by the first electrode or the second electrode included in the light-emitting element to cause an image to be projected like a mirror surface. You can keep it.

  FIG. 13B illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, a mouse 2205, and the like. The light emitting device of the present invention can be used for the display portion 2203.

  FIG. 13C illustrates a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion 2403, a recording medium (DVD or the like) reading portion 2404, An operation key 2405, a speaker portion 2406, and the like are included. The image reproducing device provided with the recording medium includes a home game machine and the like. The light emitting device of the present invention can be used for the display portion 2403.

  As described above, the applicable range of the present invention is so wide that it can be used for electronic devices in various fields. In addition, the electronic device of this embodiment may use the light emitting device having any structure shown in Embodiments 1 to 6.

4A and 4B are a top view of an element substrate and a circuit diagram of a pixel portion in the light-emitting device of the present invention. FIG. 10 is a cross-sectional view of a pixel showing a method for manufacturing a light-emitting device of the present invention. 4A and 4B are a cross-sectional view of a pixel and a top view of a pixel, illustrating a method for manufacturing a light-emitting device of the present invention. 4A and 4B are a cross-sectional view of a pixel and a top view of a pixel, illustrating a method for manufacturing a light-emitting device of the present invention. FIG. 10 is a cross-sectional view of a pixel showing a method for manufacturing a light-emitting device of the present invention. FIG. 4 is a cross-sectional view of a pixel of a light-emitting device of the present invention. FIG. 4 is a cross-sectional view of a pixel of a light-emitting device of the present invention. FIG. 6 is a top view of a pixel of the light emitting device of the present invention. 3A and 3B illustrate a stacked structure of light-emitting elements included in a light-emitting device of the present invention. 1 is a block diagram of a light emitting device of the present invention. The figure which shows a mode that the IC chip is mounted in the element substrate. 2A and 2B are a top view and a cross-sectional view of a light-emitting device of the present invention. FIG. 14 is a diagram of an electronic device using the light-emitting device of the present invention. FIG. 4 is a cross-sectional view of a pixel of a light-emitting device of the present invention.

Claims (6)

A scanning line having a gate electrode is formed by a droplet discharge method or a printing method,
Forming a gate insulating film made of silicon nitride on the gate electrode;
Forming a first electrode made of indium tin oxide containing silicon oxide in contact with the gate insulating film;
Forming a first semiconductor film on the gate insulating film so as to cover the first electrode;
Forming a protective film overlying the gate electrode on the first semiconductor film;
Patterning the first semiconductor film to expose the first electrode;
Forming a second semiconductor film to which an impurity is added so as to cover the patterned first semiconductor film, the protective film, and the first electrode;
Forming signal lines and wirings on the second semiconductor film;
Using the signal line and the wiring as a mask, the second semiconductor film is patterned to form a source region and a drain region, and a region of the first electrode other than a region overlapping with the wiring is formed. To expose
Forming a partition having an opening in the exposed region;
In the opening, an electroluminescent layer and a second electrode are formed so as to overlap with the first electrode and to be sequentially stacked,
The method for manufacturing a light-emitting device, wherein the first electrode, the protective film, the signal line, the wiring, the partition, or the second electrode is formed by a droplet discharge method or a printing method. A scanning line having a gate electrode is formed by a droplet discharge method or a printing method,
Forming a gate insulating film made of silicon nitride on the gate electrode;
Forming a first electrode made of indium tin oxide containing silicon oxide in contact with the gate insulating film;
Forming a first semiconductor film on the gate insulating film so as to cover the first electrode;
Forming a protective film overlying the gate electrode on the first semiconductor film;
Forming a second semiconductor film doped with an impurity on the first semiconductor film so as to cover the protective film;
Patterning the first semiconductor film and the second semiconductor film to expose the first electrode;
Forming a signal line in contact with the patterned second semiconductor film and a wiring in contact with a part of the patterned second semiconductor film and the first electrode;
Using the signal line and the wiring as a mask, the patterned second semiconductor film is patterned again to form a source region and a drain region,
Forming a partition having an opening through which the first electrode is exposed;
In the opening, an electroluminescent layer and a second electrode are formed so as to overlap with the first electrode and to be sequentially stacked,
The method for manufacturing a light-emitting device, wherein the first electrode, the protective film, the signal line, the wiring, the partition, or the second electrode is formed by a droplet discharge method or a printing method. A scanning line having a gate electrode is formed by a droplet discharge method or a printing method,
Forming a gate insulating film made of silicon nitride on the gate electrode;
On the gate insulating film, a first semiconductor film, a protective film overlapping the gate electrode on the first semiconductor film, and a second semiconductor film to which an impurity is added are sequentially formed.
Forming signal lines and wirings on the second semiconductor film;
A source region and a drain region are formed by patterning the second semiconductor film using the signal line and the wiring as a mask,
Forming a first electrode made of indium tin oxide containing silicon oxide so as to be in contact with the wiring and the gate insulating film;
Forming a partition having an opening through which the first electrode is exposed;
In the opening, an electroluminescent layer and a second electrode are formed so as to overlap with the first electrode and to be sequentially stacked,
The method for manufacturing a light-emitting device, wherein the first electrode, the protective film, the signal line, the wiring, the partition, or the second electrode is formed by a droplet discharge method or a printing method.   4. The droplet according to claim 1, wherein the droplet covers the transistor including the gate electrode, the gate insulating film, the first semiconductor film, the protective film, and the second semiconductor film. A method for manufacturing a light-emitting device, comprising: forming a first interlayer insulating film by a discharge method; and forming the partition as a second interlayer insulating film by a droplet discharge method on the first interlayer insulating film. . In any one of claims 1 to 4, the ZnO or TiO ₂ is deposited on the substrate surface, a method for manufacturing a light emitting device and forming the scanning lines on the ZnO or TiO _2.   6. The method for manufacturing a light-emitting device according to claim 1, wherein Ag, Au, Cu, or Pd is used for the gate electrode.

Images