JP4252634B2 - Heat treatment method for thin film - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a configuration in the case of using lamp annealing as a heat treatment method frequently used in a semiconductor device manufacturing process. In particular, the present invention is effective in manufacturing a semiconductor device such as a thin film transistor (TFT) on a glass substrate.
[0002]
[Prior art]
In recent years, the development of TFTs that are formed on a glass substrate using a semiconductor thin film (typically a thin film containing silicon as a main component) has made remarkable progress. There is an increasing demand for electro-optical devices in which a pixel matrix circuit, a driver circuit, a logic circuit, and the like are monolithically mounted on a glass substrate.
[0003]
The biggest limitation that occurs when forming TFTs on a glass substrate is the process temperature. That is, the restriction that heat treatment at a temperature higher than the heat resistant temperature of glass cannot be performed narrows the process margin.
[0004]
Therefore, laser annealing is used as a means for selectively annealing a thin film. In the laser annealing method, the sample temperature is instantaneously increased by irradiating the sample with pulsed laser light, and only the thin film can be selectively heated. However, it is a problem in the mass production process that the optical system is complicated in order to handle laser light and that it is difficult to ensure uniformity.
[0005]
Therefore, recently, a lamp annealing method using strong light emitted from an arc lamp, a halogen lamp or the like has been spotlighted. This technique is also called RTA (Rapid Thermal Annealling) or RTP (Rapid Thermal Processing), and heats the film to be processed by irradiating strong light in a wavelength region that is easily absorbed by the film to be processed.
[0006]
Normally, the lamp annealing method uses visible light to infrared light as strong light. Since light in this wavelength region is hardly absorbed by the glass substrate, it is possible to minimize the heating of the glass substrate. In addition, since the temperature rise / fall time is extremely short, a high temperature treatment at 1000 ° C. or higher can be performed in a short time of several seconds to several tens of seconds.
[0007]
Furthermore, since a complicated optical system used for laser beam processing is not required, it is suitable for processing a relatively large area with good uniformity. In addition, since the process is basically performed by single wafer processing, the yield and throughput are also high.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for improving the lamp annealing method and more effectively heat-treating a film to be processed.
[0009]
[Means for Solving the Problems]
The configuration of the invention disclosed in this specification is as follows.
In a method of heat-treating a thin film formed on a light-transmitting substrate using a lamp light source,
From the upper surface side of the thin film, strong light in a wavelength region that can electronically excite the bonds of the atoms constituting the thin film is irradiated, and at the same time, from the lower surface side of the thin film, the wavelength that can vibrationally excite the bonds. The region is irradiated with strong light.
[0010]
In addition, the configuration of other inventions is as follows:
In a method of heat-treating a thin film formed on a light-transmitting substrate using a lamp light source,
From the upper surface side of the thin film, strong light in a wavelength region that can electronically excite the bonds of the atoms constituting the thin film is irradiated, and at the same time, from the lower surface side of the thin film, the wavelength that can vibrationally excite the bonds. The area is illuminated with strong light,
The strong light in the wavelength region that can electronically excite the bond and the strong light in the wavelength region that can excite the bond are scanned from one end of the substrate to the other in a state of being processed into a linear shape. It is characterized by that.
[0011]
In order to implement the present invention having the above configuration,
An ultraviolet light lamp disposed on the upper surface side of the substrate to be processed;
An infrared lamp disposed on the lower surface side of the substrate to be processed;
Comprising at least
There is a need for a heat treatment apparatus in which the ultraviolet lamp and the infrared lamp are arranged so as to sandwich the substrate to be processed.
[0012]
Further, according to the present inventors, a configuration in which infrared light and ultraviolet light are processed into a linear shape and irradiated is the most desirable configuration of the present invention. In that case, a rod-shaped or cylindrical heat treatment apparatus in which the ultraviolet light lamp and the infrared light lamp have a longitudinal direction in a direction parallel to the substrate to be processed may be used. It is also effective to dispose cylindrical lenses between the ultraviolet light lamp and the substrate to be processed and between the infrared light lamp and the substrate to be processed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
A feature of the present invention resides in that the film to be processed is irradiated with a combination of ultraviolet light (UV light) and infrared light (IR light).
[0014]
Note that although ultraviolet light is described as typical light that gives photon energy, visible light can also be included as long as light in a wavelength region that can electronically excite the film to be processed. Typically, light having a wavelength region of 10 to 600 nm can be used.
[0015]
Similarly, infrared light has been described as representative light that gives vibration energy (also referred to as thermal energy), but visible light is also included as long as it is in a wavelength region that can excite the film to be processed. sell. Typically, light having a wavelength region of 500 nm to 20 μm can be used.
[0016]
Note that the above-described wavelength region overlaps in the visible light region of 500 to 600 nm because the wavelength region that can be excited or vibrationally excited differs depending on the film to be processed. In other words, it does not mean that electronic excitation and vibration excitation can occur simultaneously with light in the same wavelength region.
[0017]
The above ultraviolet light includes low-pressure metal vapor lamp, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, halogen arc lamp, hydrogen arc lamp, metal halide lamp, deuterium lamp, rare gas resonance line lamp, rare gas molecular emission lamp, etc. It is possible to obtain a lamp that emits ultraviolet rays as a light source.
[0018]
The infrared light can be obtained by using a lamp that emits infrared rays, such as a halogen lamp, a halogen arc lamp, or a metal halide lamp, as a light source.
[0019]
In the light irradiation treatment using ultraviolet light, the energy of photons is given to the film to be processed in the form of light absorption, and the bonds of molecules constituting the film to be processed are directly excited. Such an excitation phenomenon is called electronic excitation. Note that it is desirable to irradiate ultraviolet light from the upper surface side of the film to be processed because it is easily absorbed by the glass substrate.
[0020]
On the other hand, light irradiation treatment with infrared light gives vibration energy in the form of lattice vibration, and indirectly excites the bonds of molecules constituting the film to be processed using this as excitation energy. Such an excitation phenomenon is called vibration excitation. Note that since infrared light is not easily absorbed by the glass substrate, it can be irradiated from the lower surface side of the film to be processed.
[0021]
As described above, in the present invention, the excitation effect of the film to be processed can be further enhanced by irradiating the ultraviolet light simultaneously with the irradiation of the infrared light in the heat treatment using the lamp annealing method. That is, the effect that the efficiency of the heat treatment is greatly improved can be obtained.
[0022]
FIG. 5 is a conceptual diagram showing the difference between thermal energy and light energy, where the horizontal axis represents energy and the vertical axis represents energy density. As shown in FIG. 5, the thermal energy has an energy of average kT in terms of energy, but has an energy distribution in a wide range. On the other hand, the light energy has a certain value depending on the wavelength, that is, only the energy of hν itself.
[0023]
Therefore, for example, when a silicon film is crystal-grown, the thermal energy includes energy that destroys the crystal in addition to the energy necessary for growth, but the light energy must be efficiently irradiated with only the energy necessary for growth. Is possible.
[0024]
In this way, by appropriately selecting the wavelength of ultraviolet light, only a specific thin film can be excited intensively, so the degree of excitation of different types of processed films can be controlled, and selective excitation processing can be performed. It becomes possible. This is also one of the effects of the present invention in which ultraviolet annealing is combined with lamp annealing using infrared light.
[0025]
【Example】
[Example 1]
In this embodiment, an example in which the present invention is applied to a process for improving the crystallinity of a crystalline film containing silicon as a main component will be described with reference to FIG. Note that numerical values, materials, and the like are not limited to the present embodiment.
[0026]
In FIG. 1, 101 is a glass (or quartz) substrate used as a light-transmitting substrate, 102 is a base film made of a silicon oxide film, and 103 is a crystalline film. In this embodiment, as the crystalline film 103, a crystalline silicon film is taken as an example. _x Ge _1-x (0 <X A compound semiconductor containing silicon such as <1) can also be used.
[0027]
The crystalline silicon film also includes a single crystal silicon film, a microcrystalline silicon film, a polycrystalline silicon film, and the like. Here, a polycrystalline silicon film (so-called polysilicon film) will be described as an example.
[0028]
A method for forming the crystalline silicon film 103 may be a method of directly forming the crystalline silicon film by a low pressure thermal CVD method or the like, or a method of crystallizing an amorphous silicon film. Further, when the amorphous silicon film is obtained by crystallization, a means for crystallization by heat treatment or laser light irradiation may be taken. It is also effective to use means using a catalyst element that promotes crystallization (disclosed in Japanese Patent Laid-Open No. 7-130652).
[0029]
Reference numeral 104 denotes a lamp light source that emits ultraviolet light (ultraviolet light) (hereinafter simply referred to as an ultraviolet light lamp), 105 a reflecting mirror, and 106 a cylindrical light for condensing the ultraviolet light 107 emitted from the ultraviolet light lamp 104. It is a lens. Since the ultraviolet light lamp 104, the reflecting mirror 105, and the cylindrical lens 106 are elongated in the direction perpendicular to the paper surface, the crystalline silicon film 103 is irradiated linearly.
[0030]
In this embodiment, the ultraviolet light 107 is irradiated from the upper surface side of the crystalline silicon film 103. The upper surface side indicates the main surface side facing the ultraviolet lamp 104 in FIG. 1, that is, the surface opposite to the glass substrate 101.
[0031]
Next, 108 is a lamp light source (hereinafter simply referred to as an infrared lamp) that emits infrared light (infrared light), 109 is a reflecting mirror, and 110 is a collector of infrared light 111 emitted from the infrared light lamp 107. It is a cylindrical lens for light. Similarly to the ultraviolet light 107, the infrared light 111 is also configured to be linear light.
[0032]
Further, the crystalline silicon film 103 is irradiated from the lower surface side. Here, the lower surface side refers to the rear surface side facing the infrared lamp 108 in FIG. 1, that is, the surface facing the glass substrate 101 side.
[0033]
At this time, the infrared light 111 passes through the glass substrate without being absorbed. That is, the crystalline silicon film 103 can be efficiently heated even by irradiation from the lower surface side. Accordingly, the crystalline silicon film 103 is heated to 600 to 1200 ° C. (typically 700 to 850 ° C.) by irradiation with the infrared light 111. The film surface temperature of the crystalline silicon film 103 at this time can be measured (monitored) using a pyrometer (radiation thermometer) using a thermocouple.
[0034]
The glass substrate 101 is supported by a susceptor (not shown), and linear ultraviolet light 107 is scanned from the upper surface side of the glass substrate 101 in the direction of the arrow, and linear infrared light 111 is scanned from the lower surface side. Scanning in the direction of the arrow. In this way, the entire surface of the substrate can be irradiated by scanning linear light from one end of the glass substrate 101 toward the other end.
[0035]
In this embodiment, the ultraviolet light 107 and the infrared light 111 are designed to irradiate the same portion of the crystalline silicon film 103. The same part means that the irradiation range is the same place as shown in FIG. Of course, depending on circumstances, the scanning timing can be intentionally shifted or the scanning direction can be changed.
[0036]
The effects described below can be obtained by combining the ultraviolet light irradiation and the infrared light irradiation as described above.
[0037]
First, in addition to vibration excitation (excitation by thermal energy) by conventional infrared light irradiation, electron excitation by ultraviolet light irradiation occurs, and thus the excitation efficiency of the crystalline silicon film 103 is dramatically improved by their synergistic effect. .
[0038]
That is, the molecular bonds constituting the crystalline silicon film 103 are loosened as a whole by lattice vibration caused by infrared light irradiation, and are electronically extremely active and linked by ultraviolet light irradiation. For this reason, the crystalline silicon film 112 (the region shown by hatching in FIG. 1) subjected to the heat treatment of the present invention is formed from a very active state (a state with a high degree of freedom of coupling).
[0039]
Therefore, the crystalline silicon film 112 obtained by applying the present invention has very few crystal defects such as dangling bonds. In addition, since the crystal grain boundaries are formed by bonds having good consistency, most of them are formed by inert grain boundaries such as inclined grain boundaries.
[0040]
Since the fundamental absorption edge of silicon (silicon) is approximately 1 eV, it is considered that ultraviolet light is absorbed only on the surface having a thickness of about 10 nm to 1 μm. However, in this embodiment, the crystalline silicon film has a very thin film thickness of 10 to 75 nm (typically 15 to 45 nm), so that a sufficient excitation effect can be expected.
[0041]
In addition, since the conventional lamp annealing is a batch process on the entire surface, there is a concern that if the processing time is long, heat propagates from the film to be processed to the glass substrate and the glass substrate warps or shrinks.
[0042]
However, since the linear infrared lamp 108 is used as the light source of the infrared light 111 in the present invention, the propagation heat transferred from the crystalline silicon film 103 to the substrate 101 is only local. Therefore, the substrate 101 can be prevented from warping or shrinking due to heat.
[0043]
In this embodiment, the heat treatment method of the present invention is applied in the process of improving the crystallinity of the crystalline silicon film. However, it goes without saying that the present invention can also be applied to the crystallization process of the amorphous silicon film. .
[0044]
[Example 2]
In this embodiment, an example in which the present invention is applied to a process of activating impurity ions imparting N-type or P-type added to an active layer of a TFT will be described. In addition, although FIG. 2 is used for description, it demonstrates using the above-mentioned code | symbol as needed.
[0045]
The state shown in FIG. 2 is a stage in the middle of manufacturing a TFT on the glass substrate 101. In FIG. 2, regions 201 to 202 are active layers made of a semiconductor layer patterned in an island shape, 201 is a source region, 202 is a drain region, and 203 is a channel formation region.
[0046]
A gate insulating film 204 is formed on the active layer. The gate insulating film 204 is processed into the same shape as the gate electrode 205 disposed thereon by using the technique described in Japanese Patent Laid-Open No. 7-13318.
[0047]
The source region 201 and the drain region 202 are formed by adding impurity ions imparting one conductivity to an active layer formed of an intrinsic or substantially intrinsic crystalline silicon film. At this time, P (phosphorus) ions or As (arsenic) ions may be used when an N-channel TFT is manufactured, and B (boron) ions may be used when a P-channel TFT is manufactured.
[0048]
Next, after the impurity ion addition step is completed, ultraviolet light 107 is irradiated from the upper surface side of the substrate on which the TFT is formed, and infrared light 111 is irradiated from the lower surface side of the substrate. At this time, the ultraviolet light 107 does not reach directly under the gate electrode 205, but activation is performed without any problem because the infrared light 111 is irradiated from the lower surface side.
[0049]
The lamp annealing process in this embodiment is a process of exciting the added impurity ions to activate them. Therefore, by applying the present invention, the activation rate is greatly improved, so that the resistance of the source / drain region is lowered, and the ohmic contact between the TFT and the wiring electrode can be improved.
[0050]
Example 3
In this embodiment, an example in which the present invention is applied to a process of selectively forming a metal silicide on the surface of a source / drain region of a TFT (including the gate electrode surface if the gate electrode is silicon) will be described. In addition, although FIG. 3 is used for description, it demonstrates using the above-mentioned code | symbol as needed.
[0051]
This embodiment is characterized in that infrared light and ultraviolet light are simultaneously irradiated from the upper surface side of the substrate. That is, an optical system including an infrared lamp 301, a reflecting mirror 302, and a cylindrical lens 303 and an optical system including an ultraviolet lamp 304, a reflecting mirror 305, and a cylindrical lens 306 are disposed on the upper surface of the substrate. The infrared light 301 is irradiated with infrared light 307, and the ultraviolet light lamp 304 is irradiated with ultraviolet light lamp 308.
[0052]
In this configuration, even in the shadow area of the gate electrode 204, the infrared light 307 from the upper surface or the infrared light 111 from the lower surface side is heated. Accordingly, the silicide formation reaction can be performed uniformly over the entire substrate.
[0053]
In the case of the configuration as in this embodiment, it is preferable that the configuration is such that heating is first performed with infrared light 307 and excitation is performed with ultraviolet light 308 immediately thereafter. That is, it is considered that the excitation efficiency is higher when the bond is first loosened by vibration excitation with infrared light and then electron excitation with ultraviolet light is added in that state.
[0054]
The silicide formation process performed in the above configuration proceeds in the following order. First, after the impurity ion activation process as shown in Embodiment 2 is completed, a metal film 309 is formed so as to cover the entire TFT surface in the manufacturing process. As the metal film 309, Ti (titanium), Co (cobalt), W (tungsten), Ta (tantalum), or the like is generally used.
[0055]
When heat treatment is performed in this state, the silicon (silicon) component constituting the source region 201 and the drain region 202 reacts with the metal film 309 to form a metal silicide 310. Such a reaction proceeds at the interface between the source / drain regions 201 and 202 and the metal film 309. In this embodiment, however, the reaction rate increases due to the excitation effect of ultraviolet light irradiation, and rapid silicidation can be realized.
[0056]
Further, as a feature of lamp annealing, component atoms constituting the metal film 309 can be prevented from diffusing into the channel formation region 203. This effect is remarkable when infrared light is irradiated linearly as in this embodiment.
[0057]
Needless to say, the configuration in which infrared light and ultraviolet light are simultaneously irradiated from the upper surface side of the substrate as in this embodiment can also be applied to the first and second embodiments. In particular, when applied to the second embodiment, the junction between the source / drain region and the channel formation region and the region hidden by the gate electrode are completely activated, which is effective.
[0058]
Example 4
In this embodiment, an example in which the present invention is applied when a wiring reflow process is performed when wiring (source / drain wiring) for extracting a signal voltage from a TFT will be described. In addition, although FIG. 4 is used for description, it demonstrates using the above-mentioned code | symbol as needed.
[0059]
The reflow process is a technique for fluidizing the conductive film, which is a wiring material, by heating it so that the inside of the contact hole is completely filled with the wiring material. According to this technique, even a contact hole having a high aspect ratio can prevent contact failure such as contact failure.
[0060]
In FIG. 4, reference numeral 401 denotes an interlayer insulating film for electrically insulating and separating the gate electrode 204 and the wiring material 402. The interlayer insulating film 401 may be appropriately selected from a silicon oxide film, a silicon nitride film, an organic resin material, and the like. The wiring material 402 may be made of a material containing aluminum, tantalum, tungsten, or the like.
[0061]
In addition, it is preferable to form a metal film of germanium, tin, gallium, antimony, or the like on the upper layer or the lower layer of the above material in order to promote fluidization of the wiring material in the reflow process.
[0062]
Even if the heat treatment method of the present invention is applied to the reflow process of the wiring material 402 as in this embodiment, a synergistic effect combining ultraviolet light and infrared light can be obtained. In particular, when a metal element that promotes fluidization is used in the reflow process, the present invention is effective in promoting the reaction between the wiring material and the metal element.
[0063]
Example 5
In the present embodiment, an example in which the irradiation range of the ultraviolet light 107 and the irradiation range of the infrared light 111 are different in the configuration of the first embodiment will be described. Specifically, the irradiation range of the infrared light 111 is made wider than the irradiation range of the ultraviolet light 107. This is shown in FIG.
[0064]
In FIG. 6, reference numeral 601 denotes a glass substrate provided with a base film on the surface, and 602 denotes a crystalline silicon film. An ultraviolet lamp 603, a reflecting mirror 604, and a cylindrical lens 605 are disposed on the upper surface side of the substrate 601 and irradiated with ultraviolet light 606. In addition, an infrared light lamp 607, a reflecting mirror 608, and a cylindrical lens 609 are disposed on the lower surface side and irradiated with infrared light 610.
[0065]
At this time, the irradiation range of the infrared light 610 extends over a region (referred to as a first region) indicated by 611 to 613, and the irradiation range of the ultraviolet light 606 includes only a region indicated as 612 (referred to as a second region). It is.
[0066]
That is, the irradiation range of the infrared light 610 is designed to be wider than the irradiation range of the ultraviolet light 606. For this purpose, the length in the short side direction of the infrared light 610 processed into a linear shape may be longer than the length in the short side direction of the ultraviolet light 606 processed into a linear shape. By doing so, the first region described above includes the second region, and is wider than the second region.
[0067]
Accordingly, the crystalline silicon film 602 is heated by the infrared light 610 immediately before the irradiation with the ultraviolet light 606, and is also heated by the infrared light 610 for a short time immediately after the irradiation with the ultraviolet light 606. That is, a weakly excited state is created in the region 611, a completely excited state is created in the region 612, and a weakly excited state is maintained in the region 613.
[0068]
With the above structure, it is considered that the excited state of the crystalline silicon film 602 does not change abruptly, so that the time required for coupling can be gained. That is, it is possible to prevent the bond between atoms from being terminated in a non-equilibrium state. Thereby, a crystalline silicon film with few crystal defects can be obtained.
[0069]
Example 6
In this embodiment, an example in which an infrared auxiliary lamp is formed in parallel with an ultraviolet lamp in the configuration of the present invention will be described with reference to FIG.
[0070]
In FIG. 7A, reference numeral 701 denotes a glass substrate, and reference numeral 702 denotes an amorphous silicon film. Although an amorphous silicon film is taken as an example of the film to be processed, there is no limitation as long as it is a thin film on a glass substrate. Reference numeral 703 denotes an infrared light lamp on the lower surface side of the substrate, and reference numeral 704 denotes an ultraviolet light lamp on the upper surface side of the substrate.
[0071]
The feature of this embodiment is that a first infrared light auxiliary lamp 705 and a second infrared light auxiliary lamp 706 are arranged in parallel with the ultraviolet light lamp 704. In the present embodiment, the infrared light auxiliary lamps 705 and 706 are disposed in front and rear of the ultraviolet light lamp 704 (with respect to the moving direction of the substrate), but may be disposed only on one side. it can.
[0072]
In the above configuration, each of the lamps 703 to 706 moves in the direction of the arrow in the drawing, and scans linear light. In the structure of this embodiment, first, the amorphous silicon film 702 is heated by being irradiated with infrared light by the first infrared auxiliary lamp 705. This area becomes a preheat area 707 and moves forward as the substrate moves.
[0073]
Behind the preheat region 707, ultraviolet light from the ultraviolet light lamp 704 is irradiated from the upper surface side of the substrate, and infrared light from the infrared light lamp 703 is irradiated from the lower surface side of the substrate to form a main heat region 708. The In this embodiment, the amorphous silicon film 702 is crystallized in the main heat region 708.
[0074]
A post heat region 709 heated by infrared light from the second infrared light auxiliary lamp 706 is formed behind the main heat region 708. This region is a region where the crystalline silicon film obtained in the main heat region 708 is heated.
[0075]
As described above, the amorphous silicon film (which becomes a crystalline silicon film in the middle) 702 is a region in which the preheat region 707, the main heat region 708, and the post heat region 709 are arranged in this order, and apparently as the substrate moves. Move forward.
[0076]
Here, FIG. 7B shows the relationship between time (Time) and temperature (Temp.) At a certain point of the amorphous silicon film 702. As shown in FIG. 7 (B), the preheat region first follows with the passage of time, followed by the main heat region and the postheat region.
[0077]
As is apparent from FIG. 7B, the temperature is increased to some extent in the preheat region 707, and plays a role of relaxing the temperature gradient with the next main heat region 708. This is a device for preventing the strain energy and the like from accumulating in the silicon film due to abrupt heating in the main heat region 708.
[0078]
Therefore, it is desirable to set the output energy of the first auxiliary infrared light lamp 705 to be smaller than the output energy of the infrared light lamp 703. At this time, the practitioner may appropriately determine what temperature gradient is adjusted to form.
[0079]
Next, when passing through the preheat region 707, infrared light is irradiated from the lower surface side of the substrate, and the main heat region 708 is raised to a film surface temperature of 600 to 1200 ° C. In this region, the amorphous silicon film 702 is transformed into a crystalline silicon film. In addition, since the ultraviolet light irradiated simultaneously contributes to electronic excitation, it does not bring about a thermal change.
[0080]
The crystalline silicon film obtained in the main heat region 708 is heated by a second infrared light auxiliary lamp 706 disposed behind the ultraviolet light lamp 704. The post heat region 709 serves to prevent the crystallization from being finished in a state where the thermal equilibrium is lost due to the rapid cooling of the main heat region 708. This is a contrivance for obtaining the most stable bonding state with a sufficient time for crystallization.
[0081]
Therefore, the second auxiliary infrared light lamp 706 can also be adjusted so as to form a temperature gradient that gradually decreases the temperature by setting the output energy smaller than the infrared light lamp 703 disposed on the lower surface of the substrate. desirable.
[0082]
By adopting the structure as described above, the occurrence of crystal defects such as stress strain and dangling bonds caused by rapid heating of the amorphous silicon film and rapid cooling of the crystalline silicon film is suppressed, and the crystallinity is excellent. A crystalline silicon film can be obtained.
[0083]
Example 7
In this embodiment, an outline of the configuration of a heat treatment apparatus necessary for carrying out the present invention will be described. The greatest feature of the present invention is that heat treatment is performed by simultaneously irradiating ultraviolet light and infrared light, and the apparatus configuration capable of implementing the configuration is not limited to this embodiment.
[0084]
FIG. 8A is a simplified view of the heat treatment apparatus necessary for carrying out the first to fifth embodiments when viewed from the lateral direction. FIG. 8B shows the heat treatment apparatus as viewed from above.
[0085]
8A, a substrate transfer unit (including an arm and a control circuit) 802, a cassette 803 for storing a substrate to be processed, and a susceptor transfer unit 804 are arranged in a load lock chamber 801. A processing chamber 806 is connected to the load lock chamber 801 via a gate valve 805.
[0086]
In the processing chamber 806, an ultraviolet light source (including an ultraviolet light lamp, a reflecting mirror, and a cylindrical lens) 807, and an infrared light source (including an infrared light lamp, a reflecting mirror, and a cylindrical lens) 808 are included in the susceptor 809 and the object to be processed. The substrate 810 is disposed so as to be sandwiched therebetween. Further, it has a longitudinal direction in a direction perpendicular to the paper surface.
[0087]
In addition, as illustrated in FIG. 8B, atmospheric gas is supplied to the processing chamber 806 from the introduction port 811. At that time, the flow rate is adjusted by a valve 812. In addition, although atmospheric gas changes with processes, the gas which does not produce | generate a solid substance by ultraviolet light irradiation is desirable.
[0088]
In addition, the atmospheric gas introduced into the processing chamber 806 is exhausted from the exhaust port 813. At this time, an exhaust pump 814 is preferably provided as necessary. If there is no need to use an exhaust pump, a facility similar to an exhaust scrubber is sufficient.
[0089]
In the apparatus having such a configuration, first, the substrate to be processed 810 is unloaded from the cassette 803 by the substrate transfer unit 802. Then, the substrate to be processed 810 is placed on the susceptor 809 on the susceptor transfer unit 804 and transferred to the processing chamber 806 together with the susceptor.
[0090]
In the processing chamber 806, an ultraviolet light source 807 and an infrared light source 808 that emit linear light move from one end of the substrate 810 to the other end, and heat treatment using linear light is performed. At that time, the irradiation regions of the ultraviolet light and the infrared light may be completely overlapped or may be configured to be shifted back and forth.
[0091]
When the heat treatment is completed, the susceptor 809 is returned to the load lock chamber 801 by the susceptor transfer unit 804, and the substrate to be processed 810 is stored in the cassette 803 by the substrate transfer unit 802. As described above, a series of operations is repeated to perform single-wafer heating.
[0092]
In addition, a present Example is one Example of an apparatus required in order to implement this invention, A structure etc. are not limited to this. For example, the linear light source may be fixed and the substrate may be moved to scan the linear light.
[0093]
Example 8
In this embodiment, an example in which a heat treatment apparatus having a configuration different from that in Embodiment 7 is used will be described. The description will be given with reference to FIG.
[0094]
FIG. 9A shows a multi-chamber type (cluster tool type) single wafer type heat treatment apparatus. Load lock chambers 902 and 903, a preheat chamber (or post heat chamber) 904, and heating furnaces 905 to 907 are connected to the main frame 901. In addition, cassettes 908 and 909 for storing substrates are installed in the load lock chambers 902 and 903, respectively.
[0095]
Gate valves 910 to 915 are provided between the main frame 901 and each chamber, respectively, so that the main frame 901 can be kept sealed. Each chamber is provided with an evacuation pump (not shown) corresponding to a high vacuum so that each chamber is not exposed to the atmosphere.
[0096]
First, the substrate 917 is unloaded from the load lock chamber 902 by the transfer unit 916 installed on the main frame 901. Then, the substrate 917 is heated to a certain degree in the preheating chamber 904, and then carried into one of the heating furnaces 905 to 907. Note that the preheat chamber 904 can be omitted.
[0097]
Inside the heating furnaces 905 to 907, light sources 918 to 920 having a size capable of heating the substrates 917 at once are installed. Although it looks like one light source in FIG. 9A, actually, as shown in FIG. 9B, a light source 921 that emits ultraviolet light and a light source that emits infrared light to one heating furnace. 922 is installed.
[0098]
When the heat treatment is finished in any of the heating furnaces 905 to 907, the substrate 917 is unloaded again by the transfer unit 916 and loaded into the load lock chamber 903. Of course, it is good also as a structure which passes a post-heating process.
[0099]
Here, paying attention to the heating furnace 905, its internal structure will be briefly described with reference to FIG. Inside the heating furnaces 905 to 907 are a control unit 923 for adjusting the output of the ultraviolet light source 921 and feedback of temperature information, and a control unit 924 for adjusting the output of the infrared light source 922 and feedback of temperature information. Is arranged.
[0100]
In addition, loading / unloading of substrates to / from the heating furnace 905 is performed by a transfer unit 916 provided in the main frame 901. The transport unit 916 is controlled by the transport unit 925 and can freely transport the substrate 917 in the direction of the arrow.
[0101]
A susceptor 926 is attached to the upper control unit 923 in the heating furnace 905, and the substrate 917 is supported with the main surface (side on which the TFT is manufactured) facing the ultraviolet light source 921 side.
[0102]
By irradiating ultraviolet light and infrared light in this state, the effect of the present invention can be obtained. In this embodiment, since light irradiation is performed collectively using a light source having a plurality of infrared light or ultraviolet light lamps, there is no advantage in using linear light as shown in the first embodiment. . However, it is possible to suppress warping and shrinkage of the glass substrate by shortening the processing time.
[0103]
【The invention's effect】
As described above, in the present invention, the excitation efficiency of the film to be processed can be further increased by simultaneously irradiating infrared light and ultraviolet light. That is, the efficiency of the heat treatment can be greatly improved.
[0104]
In addition, heat treatment at a high temperature of 600 to 1200 ° C. can be performed without warping or shrinking the glass substrate by irradiation with linear ultraviolet light and infrared light.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of heat treatment according to the present invention.
FIG. 2 is a diagram showing a configuration of heat treatment according to the present invention.
FIG. 3 is a diagram showing a configuration of heat treatment according to the present invention.
FIG. 4 is a diagram showing a configuration of heat treatment according to the present invention.
FIG. 5 is a diagram showing the difference between thermal energy and light energy.
FIG. 6 is a diagram showing a configuration of heat treatment according to the present invention.
FIG. 7 is a diagram showing a configuration of heat treatment according to the present invention.
FIG. 8 shows a heat treatment apparatus used in the present invention.
FIG. 9 shows a heat treatment apparatus used in the present invention.
[Explanation of symbols]
101 glass substrate
102 Base film
103 crystalline silicon film
104 UV lamp
105 Reflector
106 Cylindrical lens
107 UV light
108 Infrared lamp
109 Reflector
110 Cylindrical lens
111 infrared light
112 Crystalline silicon film with improved crystallinity

Claims (6)

The silicon film is simultaneously irradiated with the first light using the first lamp light source to the first region of the silicon film from the upper surface side of the silicon film formed on the light-transmitting glass substrate. Irradiating the second region of the silicon film with the second light from the lower surface side using the second lamp light source opposed to the first lamp light source,
The first region and the second region overlap,
The first light is ultraviolet light included in a wavelength of 10 nm to 600 nm, the second light is infrared light included in a wavelength of 500 nm to 20 μm, and the wavelength of the first light and the second light are A method for heat-treating a thin film, characterized by being different from the wavelength of. The silicon film is simultaneously irradiated with the first light using the first lamp light source to the first region of the silicon film from the upper surface side of the silicon film formed on the light-transmitting glass substrate. Irradiating the second region of the silicon film with the second light from the lower surface side using the second lamp light source opposed to the first lamp light source,
The first region and the second region overlap,
The first light is ultraviolet light included in a wavelength of 10 nm to 600 nm, the second light is infrared light included in a wavelength of 500 nm to 20 μm, and the wavelength of the first light and the second light are Unlike the wavelength of
A thin film heat treatment method, wherein the first light and the second light are processed into a linear shape and scanned from one end to the other end of the substrate. 3. The second region according to claim 2 , wherein the second region irradiated with the second light includes the first region irradiated with the first light and is wider than the first region. Heat treatment method for thin film. 4. The third lamp light source according to claim 2 , wherein a third lamp light source is used from the upper surface side of the silicon film immediately before or immediately after the first region of the silicon film is irradiated with the first light. Irradiate with light,
The third light is infrared light included in a wavelength of 500 nm to 20 μm, and the thin film heat treatment method is characterized in that the wavelength of the first light is different from the wavelength of the third light. 5. The thin film heat treatment method according to claim 4 , wherein the output energy of the third lamp light source is smaller than the output energy of the second lamp light source. Irradiation of the first light using the first lamp light source and the third lamp light source are used on the first region of the silicon film from the upper surface side of the silicon film formed on the light-transmitting glass substrate. Irradiating the second light using the second lamp light source to the second region of the silicon film by the RTA method from the lower surface side of the silicon film,
The first region and the second region overlap,
The first light is ultraviolet light included in a wavelength of 10 nm to 600 nm, the second light and the third light are infrared light included in a wavelength of 500 nm to 20 μm, and the wavelength of the first light And the wavelength of the second light is different from the wavelength of the first light and the wavelength of the third light.

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