JP4524223B2 - Functional device and method for manufacturing the same, solid-state imaging device and method for manufacturing the same - Google Patents

Description

  The present invention relates to a functional element and a manufacturing method thereof, and a solid-state imaging element and a manufacturing method thereof, and in particular, a photoelectric conversion element including a photoelectric conversion film containing an organic material and a translucent electrode laminated on the photoelectric conversion film, and The present invention relates to a solid-state imaging device including such a photoelectric conversion device and a manufacturing method thereof.

  As a prototype element of the photoelectric conversion film laminated solid-state imaging device, for example, there is one described in Patent Document 1 below. In this solid-state imaging device, three photosensitive layers are stacked on a semiconductor substrate, and red (R), green (G), and blue (B) electrical signals detected in each photosensitive layer are transmitted to the surface of the semiconductor substrate. Reading is performed by the MOS circuit formed in the circuit.

  A solid-state imaging device having such a configuration has been proposed in the past. Thereafter, a large number of light receiving portions (photodiodes) are integrated on the surface portion of the semiconductor substrate, and red (R), green (G), blue ( B) CCD image sensors and CMOS image sensors with stacked color filters of each color have made significant progress. Currently, digital still cameras are equipped with image sensors that integrate millions of light-receiving parts (pixels) on a single chip. It is supposed to be done.

  However, the CCD type image sensor and the CMOS type image sensor are approaching the limits of the technology, and the size of the light receiving area (opening) of one light receiving unit is about 2 μm, which is close to the wavelength order of incident light. We face the problem of poor manufacturing yield.

  In addition, the upper limit of the amount of photocharge accumulated in one miniaturized light receiving portion is as small as about 3000 electrons, and it has become difficult to express 256 gradations. For this reason, it is difficult to expect an image sensor higher than that of the conventional CCD type or CMOS type in terms of image quality and sensitivity.

  Thus, as a solid-state imaging device that solves these problems, the structure of the solid-state imaging device proposed in Patent Document 1 has been reviewed, and image sensors described in Patent Document 2 and Patent Document 3 have been newly proposed. Yes.

  In the image sensor described in Patent Document 2, ultrafine particles of silicon are dispersed in a medium to form a photoelectric conversion layer, and a plurality of photoelectric conversion layers having different ultrafine particle sizes are stacked on a semiconductor substrate. In each of the photoelectric conversion layers, electrical signals corresponding to the received light amounts of red, green, and blue are generated.

The same applies to the image sensor described in Patent Document 3, in which three nanosilicon layers having different particle diameters are stacked on a semiconductor substrate, and red, green, and blue electrical signals detected by the respective nanosilicon layers are detected. Is read out to the storage diode formed on the surface portion of the semiconductor substrate.
Further, when the photoelectric conversion film having such a configuration is stacked on a semiconductor substrate, two light-transmitting electrodes are stacked with each photoelectric conversion film interposed therebetween. Although this translucent electrode may need to be patterned, methods described in Patent Documents 4 and 5 below have been proposed as general translucent electrode patterning methods.

JP 58-103165 A Japanese Patent No. 3405099 Japanese Patent Laid-Open No. 2002-83946 JP 2000-150466 A JP 2000-150467 A

In order to put the photoelectric conversion film laminated solid-state imaging device into practical use, it is necessary to solve the problem of what material the photoelectric conversion film is formed of. In the prior arts described in Patent Documents 2 and 3 described above, the photoelectric conversion film is composed of silicon ultrafine particles or a nanosilicon layer, but more realistically, existing materials such as organic materials such as organic semiconductors are used. It can be said that it is preferable to form a photoelectric conversion film.
However, when a photoelectric conversion film or a translucent electrode containing an organic material is laminated on a semiconductor substrate, and the method described in Patent Documents 4 and 5 described above is applied, the translucent electrode is patterned. There is a problem that the photoelectric conversion characteristics of the image quality deteriorate and an image with high resolution cannot be captured.

The present invention has been made in view of the above circumstances, and an object of the present invention is to manufacture a highly reliable functional element without causing deterioration of characteristics of a functional film containing an organic material.
It is another object of the present invention to provide a functional element in which a photoelectric conversion film containing an organic material and a light-transmitting electrode are stacked without deteriorating the photoelectric conversion characteristics of the photoelectric conversion film, and a method for manufacturing the functional element.

The method for producing a functional element of the present invention is a method for producing a functional element having a translucent electrode film on a layer containing an organic material as a functional layer, and the patterning step of the translucent electrode film includes: look including fast etching step of etching the light transmitting electrode layer at 10 nm / min or more etch rate, the faster the etching process, the ends of etching the translucent electrode while leaving a predetermined amount, the patterning step is And a low-speed etching step of etching the remaining light-transmitting electrode at a rate lower than the etching rate of the high-speed etching step after the high-speed etching step, and processing with reducing plasma prior to the low-speed etching step. a step, after the treatment with the reducing plasma, and performing etching by irradiating argon ions is including ones.
The method for producing a functional element of the present invention is a method for producing a functional element comprising a translucent electrode film on a film containing an organic material as a functional layer, the patterning step for the translucent electrode film. Includes a high-speed etching step of etching the translucent electrode film at an etching rate of 10 nm / min or more, and in the patterning step, the hard including at least one of silicon oxide (SiO ₂ ) and silicon nitride (SiN _x ) A mask is used.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

In the method for producing a functional element of the present invention, the etchant gas used in the high-speed etching step includes at least one of HI, HBr, HCl, CH ₄ , and CH ₃ OH.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

In the method for producing a functional element of the present invention, the translucent electrode includes at least one of ITO, IZO, SnO ₂ , ATO, ZnO, and FTO.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

  In the functional element manufacturing method of the present invention, the high-speed etching step ends the etching leaving a predetermined amount of the translucent electrode, and the patterning step includes the etching in the high-speed etching step after the high-speed etching step. A low-speed etching step of etching the remaining translucent electrode at a rate slower than the rate.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

In the method of manufacturing a functional element according to the present invention, the etchant gas used in the low-speed etching step includes at least one of HI, HBr, HCl, CH ₄ , CH ₃ OH, BCl ₃ , and Cl ₂ .

  By this method, deterioration of photoelectric conversion characteristics of the functional element can be prevented, and reliability can be improved. In particular, when a reducing gas such as HCl is included, patterning can be performed while reducing the precipitate during dry etching, and there is no deterioration in device characteristics due to precipitation of the reaction product.

  In the method of manufacturing a functional element according to the present invention, the translucent electrode includes a first translucent electrode and a second translucent electrode laminated on the first translucent electrode, and the high speed The second translucent electrode is etched in the etching process, and the first translucent electrode is etched in the low-speed etching process.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

  In the method for producing a functional element of the present invention, the first translucent electrode has etching resistance to an etchant containing halogen.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

In the present invention, the high-speed or low-speed etching step includes a step of dry etching using at least one gas selected from HCl, HBr, and HI.
With this configuration, reliability can be improved. In particular, when a reducing gas such as HCl is included, patterning can be performed while reducing the precipitate during dry etching, and there is no deterioration in device characteristics due to precipitation of the reaction product.

In the present invention, the high-speed or low-speed etching step includes a step of performing dry etching using at least one gas selected from CH ₄ and CH ₃ OH.
With this configuration, reliability can be improved. In particular, during dry etching, patterning can be performed while reducing precipitates, and since the reaction proceeds slowly, there is no deterioration in device characteristics due to precipitation of reaction products.

In the present invention, the low-speed etching step includes a step of dry etching using at least one gas selected from Ar and N ₂ .
With this configuration, reliability can be improved. In particular, during dry etching, precipitates can be removed while sputtering with inert gas ions, and since the reaction proceeds slowly, there is no deterioration in device characteristics due to precipitation of reaction products. Etching in the present invention includes not only chemical etching accompanied by a chemical reaction but also physical etching such as cutting using ion bombardment.

Moreover, in this invention, the process processed with a reducing plasma is included prior to the said low-speed etching process.
With this configuration, the deposit can be reduced and removed first, and patterning can be performed, and deterioration of device characteristics due to deposition of the reaction product can be prevented.

In the present invention, the reducing plasma is selected from carbon (C), hydrogen (H), nitrogen (N), sulfur (S), iodine (I), chlorine (Cl), and bromine (Br). Includes atoms or molecules containing at least one element.
With this configuration, the reliability can be further improved.

In the present invention, the reducing plasma may be carbon monoxide (CO), hydrogen (H ₂ ), nitrogen monoxide (NO), sulfur monoxide (SO), iodine (I ₂ ), chlorine (Cl ₂ ), It contains at least one molecule selected from bromine (Br ₂ ).
With this configuration, it is possible to further improve the reliability by forming a stacked functional element.

Moreover, in this invention, after the process by the said reducing plasma, the process of etching by irradiating argon ion is included.
With this configuration, when the electrode film is a metal due to reducing plasma, the film becomes a metal-rich film and can be easily etched with argon ions. Therefore, etching can be easily performed without increasing the temperature. For example, a metal oxide film such as ITO becomes a metal-rich film by reducing plasma such as hydrogen plasma and is easily removed by argon ions.

In the method for producing a functional element of the present invention, the second light-transmitting electrode includes at least one of ITO, IZO, SnO ₂ , ATO, ZnO, and FTO, and the first light-transmitting electrode is In, At least one of W, TaN, Nb, Pt, and Ga is included.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

  In the method for manufacturing a functional element of the present invention, the input power during the etching is 100 W or more and 4 kW or less.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

  In the method for producing a functional element of the present invention, the pressure in the chamber during the etching is 0.01 Pa or more and 50 Pa or less.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

The functional element manufacturing method of the present invention uses a hard mask containing at least one of SiO ₂ and SiNx in the patterning step.

  By this method, deterioration of the photoelectric conversion characteristics of the functional element can be prevented.

  The method for manufacturing a solid-state imaging device according to the present invention includes a substrate on which a signal readout circuit is formed, a photoelectric conversion film including an organic material stacked on the substrate, and a translucent electrode stacked on the photoelectric conversion film. A method for manufacturing a solid-state imaging device having a functional element, wherein the functional element is manufactured by the method for manufacturing the functional element.

  The photoelectric conversion element of the present invention is a photoelectric conversion element including a photoelectric conversion film containing an organic material and a translucent electrode laminated on the photoelectric conversion film, wherein the translucent electrode is a first translucent electrode. It is comprised from a 2nd translucent electrode laminated | stacked on a photoconductive electrode and a said 1st translucent electrode.

In the functional element of the present invention, the first translucent electrode includes at least one of In, W, TaN, Nb, Pt, and Ga, and the second translucent electrode is ITO, IZO, SnO _2. , ATO, ZnO, and FTO.

  The solid-state imaging device of the present invention is a solid-state imaging device including the functional element stacked above a substrate on which a signal readout circuit is formed.

  ADVANTAGE OF THE INVENTION According to this invention, the functional element which laminated | stacked the photoelectric converting film containing an organic material, and the translucent electrode, and its manufacturing method can be provided, without degrading the photoelectric conversion characteristic of a photoelectric converting film.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of two pixels of a photoelectric conversion film stacked solid-state imaging device according to an embodiment of the present invention. In this embodiment, three layers of photoelectric conversion films are stacked, and an electrical signal corresponding to the three primary colors of red (R), green (G), and blue (B) is extracted, that is, a configuration for capturing a color image. It has become. In this laminated structure, the patterning process of the translucent electrode film 11 formed of the organic material layer formed on the upper layer of the photoelectric conversion film is performed at a high speed for etching the translucent electrode film at an etching rate of 10 nm / min or more. An etching process is included.
Note that a configuration in which only one layer of the photoelectric conversion film is provided and a monochrome image such as a monochrome image is captured may be used.
In addition to four layers of photoelectric conversion films, in addition to the three primary colors red, green, and blue, for example, an intermediate color between blue and green (emerald color: equivalent to the negative sensitivity of human red visibility) is detected. The red detection signal may be corrected with the intermediate color detection signal.

  In FIG. 1, on a surface portion of a P-well layer 1 formed on an n-type silicon substrate, a high-concentration impurity region 2 for red signal storage, a MOS circuit 3 for reading red signal, and a high-level signal for green signal storage. A concentration impurity region 4, a green signal readout MOS circuit 5, a blue signal storage high concentration impurity region 6, and a blue signal readout MOS circuit 7 are formed.

  Each MOS circuit 3, 5, 7 is composed of a source and drain impurity region formed on the surface of the semiconductor substrate and a gate electrode formed via a gate insulating film 8. An insulating film 9 is laminated and planarized on the gate insulating film 8 and the gate electrode. A light shielding film 10 is formed on the surface of the insulating film 9. Since the light shielding film 10 is often formed of a metal thin film, an insulating film 11 is further laminated thereon. When the light shielding film 10 is not provided at this location, the illustrated insulating films 9 and 11 may be integrated.

  The signal charges of the respective colors (red, green, and blue) generated in the photoelectric conversion films 14, 19, and 24, which will be described later, are accumulated in the above-described high-concentration impurity regions 2, 4, and 6 for color signal accumulation, respectively. Is read out by the MOS circuits 3, 5, and 7. Further, although not shown in the figure, the signal is taken out by the readout electrode formed on the semiconductor substrate, but the configuration is the same as that of the conventional CMOS type image. It is the same as the sensor.

  In this example, a signal corresponding to the amount of signal charge is read out by a MOS circuit formed on a semiconductor substrate. However, the charge stored in the high-concentration impurity regions 2, 4, and 6 for storing color signals is used as a conventional CCD. Similar to the type image sensor, it may be configured to move along the vertical transfer path and read out along the horizontal transfer path.

  The above configuration is manufactured by a conventional CCD image sensor or CMOS image sensor semiconductor process, and a photoelectric conversion film stacked solid-state imaging device is manufactured by adding the configuration described below.

A translucent electrode film 12 is formed on the insulating film 11 shown in FIG. The translucent electrode film 12 is separated for each pixel by etching after film formation. The translucent electrode film (red pixel electrode film) 12 for each pixel is electrically connected to the high concentration impurity region 2 for red signal accumulation by the electrode 13. The electrode 13 is electrically insulated from areas other than the red pixel electrode film 12 and the high concentration impurity region 2.
Then, for example, a red detection photoelectric conversion film 14 is formed on the red pixel electrode film 12, and a translucent electrode film (a counter electrode film facing the pixel electrode film 12) 15 is further formed thereon. The counter electrode film 15 is patterned into a desired shape (for example, a shape separated for each pixel) after being formed. That is, the red detection photoelectric conversion film 14 is sandwiched between the pair of translucent electrode films 12 and 15. Note that the electrode film 12 as the lowermost layer can be made of a non-translucent material and can also be used as a light shielding film. In the present embodiment, the translucent electrode films 12 and 15 and the red color detection photoelectric conversion film 14 function as one photoelectric conversion element.

A translucent insulating film 16 is formed on the counter electrode film 15, and a translucent electrode film 17 is formed thereon. The translucent electrode film 17 is formed as a single piece and then separated for each pixel by etching. The translucent electrode film (green pixel electrode film) 17 for each pixel is connected to the high-concentration impurity region 4 for storing the green signal by a contact plug 18. This electrode 18 is electrically insulated from areas other than the green pixel electrode film 17 and the high concentration impurity region 4.
For example, a green color detection photoelectric conversion film 19 is formed on the green pixel electrode film 17, and a translucent electrode film (counter electrode film) 20 is further formed on the green pixel electrode film 17. After the counter electrode film 20 is formed, it is patterned into a desired shape (for example, a shape separated for each pixel). That is, the green detection photoelectric conversion film 19 is sandwiched between the pair of translucent electrode films 17 and 20. In the present embodiment, the translucent electrode films 17 and 20 and the green color detecting photoelectric conversion film 19 function as one photoelectric conversion element.

A translucent insulating film 21 is formed on the counter electrode film 20, and a translucent electrode film 22 is formed thereon. After the translucent electrode film 22 is formed, it is separated for each pixel by etching. The translucent electrode film (blue pixel electrode film) 22 for each pixel is connected to the high-concentration impurity region 6 for storing a blue signal by a contact plug 23. This electrode 23 is electrically insulated from areas other than the blue pixel electrode film 22 and the high concentration impurity region 6.
For example, a single blue detection photoelectric conversion film 24 is formed on the blue pixel electrode film 22, and a translucent electrode film (counter electrode film) 25 is formed on the blue pixel electrode film 22. After the counter electrode film 25 is formed, it is patterned into a desired shape (for example, a shape separated for each pixel). That is, the blue detection photoelectric conversion film 24 is sandwiched between the pair of translucent electrode films 22 and 25. Then, a light-transmitting insulating film 26 for passivation is provided on the uppermost layer. In the present embodiment, the translucent electrode films 22 and 25 and the blue color detection photoelectric conversion film 24 function as one photoelectric conversion element.

The material of the homogeneous translucent electrode film 12, 15, 17, 20, 22, 25 is conductive metal oxide such as tin oxide, zinc oxide, indium oxide, indium zinc oxide (IZO), indium tin oxide (ITO), etc. Products, gold, platinum, silver, chromium, nickel and other thin semi-transparent electrode films, and mixtures or laminates of these metals and conductive metal oxides, copper iodide, sulfide Examples thereof include inorganic conductive materials such as copper, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO. Also described in detail by Yutaka Sawada, "New development of translucent conductive film" (published by CMC, 1999), Japan Society for the Promotion of Science "Technology of translucent conductive film" (Ohm, 1999), etc. You may use what is done. Particularly preferred is at least one material selected from ITO, IZO, SnO ₂ , ATO, ZnO, FTO and the like. The transmittance of the translucent electrode film is preferably 60% to 98%, more preferably 80% to 98%. As a method for forming the light-transmitting electrode film, there are a laser abrasion method, a sputtering method, and the like. FIG. 1 illustrates the case where the translucent electrode film has a single-layer structure.

  The photoelectric conversion films 14, 19, and 24 are configured to include an organic material such as an organic semiconductor. Examples of organic semiconductors include a hole transport material and an electron transport material. Examples of the hole transport material include poly-N-vinylcarbazole derivatives, polyphenylene vinylene derivatives, polyphenylene, polythiophene, polymethylphenylsilane, polyaniline, triazole derivatives, oxalates. Diazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, carbazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, Polyphyrin derivatives (phthalocyanine, etc.), aromatic tertiary amine compounds and styrylamine compounds, butadiene compounds, benzidine derivatives, Styrene derivatives, triphenylmethane derivatives, tetraphenyl benzene derivatives, starburst polyamine derivative or the like can be used. Also, electron transport organic materials include oxadiazole derivatives, triazole derivatives, triazine derivatives, nitro-substituted fluorenone derivatives, thiopyrandioxide derivatives, diphenylquinone derivatives, perylene tetracarboxyl derivatives, anthraquinodimethane derivatives, fluorenylidenemethanes. Derivatives, anthrone derivatives, perinone derivatives, oxine derivatives, quinoline complex derivatives, and the like.

  Organic dyes may be used as the organic material. Examples of organic dyes include metal complex dyes, cyanine dyes, merocyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, and xanthene dyes. Dyes, macrocyclic azaannulene dyes, azulene dyes, naphthoquinones, anthraquinone dyes, chain compounds condensed with condensed polycyclic aromatic and aromatic or heterocyclic compounds such as anthracene, pyrene, squarylium groups and croconic methine groups Cyanine-like dyes having a linking chain and bound by two nitrogen-containing heterocycles such as quinoline, benzothiazole and benzoxazole, squarylium group and croconite methine group can be preferably used. In the case of a metal complex dye, a dithiol metal complex dye, a metal phthalocyanine dye, a metal porphyrin dye or a ruthenium complex dye is preferable, and a ruthenium complex dye is particularly preferable. Examples of the ruthenium complex dye include, for example, U.S. Pat. Nos. 4,972,721, 4,684,537, 5,844,365, 5,350,644, 5,630,57, 5,525,440, JP-A-7-249790, JP-A-10-504512, WO98 / 50393. And complex dyes described in JP-A-2000-26487. Specific examples of polymethine dyes such as cyanine dyes, merocyanine dyes and squarylium dyes are disclosed in JP-A-11-35836, JP-A-11-67285, JP-A-11-86916, JP-A-11-97725, JP-A-11-97725. -158395, JP-A-11-163378, JP-A-11-214730, JP-A-11-214731, JP-A-11-238905, JP-A-2000-26487, European Patents 892411, 918441 and 991092 It is a pigment described in the publication No ..

Hereinafter, the patterning process of the counter electrode film 25 will be described. Since the patterning process of the counter electrode films 15 and 20 is the same as the patterning process of the counter electrode film 25, the description thereof is omitted.
FIG. 2 is a view for explaining a patterning process of the counter electrode film in a circled portion shown in FIG.
As shown in FIG. 2, in the patterning process of the counter electrode film 25, after the counter electrode film 25 is formed on the blue detection photoelectric conversion film 24, at least one of SiO ₂ and SiNx is included by a CVD method or the like. A material thin film is formed and patterned using a resist pattern (not shown) formed by photolithography as a mask to form a hard mask 30 composed of a material thin film containing at least one of SiO ₂ and SiNx (FIG. 2A). )). FIG. 2A shows a state in which the resist pattern is removed by ashing. Thereafter, the counter electrode film is etched using the hard mask as a mask. The counter electrode film 25 has a thickness of, for example, 0.15 μm. In this embodiment mode, etching refers to dry etching such as chemical etching or sputtering.

  In the etching process, a high-speed etching process is performed in which the counter electrode film 25 is etched to the surface of the blue color detection photoelectric conversion film 24 at an etching rate of 10 nm / min or more (hereinafter referred to as a first etching rate) (FIG. 2B). After the high speed etching process, the hard mask 30 is peeled off and the patterning process is completed. The etching rate can be adjusted by the etchant gas type, the material of the counter electrode film 25, the input power during etching, the pressure in the chamber during etching, and the like. When etching a translucent electrode laminated on a photoelectric conversion film containing an organic material, if an etchant gas is introduced for a long time, the photoelectric conversion film containing the organic material is damaged, resulting in photoelectric conversion characteristics. Will deteriorate. Therefore, as in this embodiment, the etching rate is set to 10 nm / min or more and the etching is completed in a time that does not damage the photoelectric conversion film, thereby preventing damage to the photoelectric conversion film to a minimum. And deterioration of the photoelectric conversion characteristics can be prevented. That is, the important point in the present invention is that when an organic material is included in the photoelectric conversion film, the photoelectric conversion characteristics of the photoelectric conversion film are prevented in order to prevent the deterioration of the organic material in the etching process or the interface reaction between the organic material and the electrode film. Etching is performed at a rate of 10 nm / min or more in order to etch the translucent electrode without impairing the thickness.

  Note that the pixel electrode film 22, the photoelectric conversion film are added by adding a low-speed etching process in which the etching rate is made lower than the first etching rate immediately before the etching is finished without making the etching rate constant. 24, the photoelectric conversion characteristics of the photoelectric conversion element including the counter electrode film 25 can be improved.

  That is, in the patterning step, first, a high-speed etching step of etching the counter electrode film 25 at a first etching rate (for example, 10 nm / min) is allowed to allow damage to the blue detection photoelectric conversion film 24. After the etching is completed in a state in which the counter electrode film 25 is left in a predetermined amount (for example, 1/15 of the thickness of the counter electrode film 25), the etching rate is lower than the first etching rate. The remaining counter electrode film 25 that was not etched in the high-speed etching process after the second etching rate (for example, 1 nm / min, 1/10 of the first etching rate) A low-speed etching process for etching to the surface of the film 24 is performed. In this way, the etching process is divided into two stages, a high-speed etching process and a low-speed etching process, and at a position close to the photoelectric conversion film 24, the etching rate is reduced to further prevent damage to the photoelectric conversion film. It is possible to further prevent deterioration of the photoelectric conversion characteristics.

In this low-speed etching process, after processing with reducing plasma, that is, plasma containing reducing molecules or atoms, during dry etching, HCl, HBr, HI, CH ₄ , CH ₃ OH, Ar, N ₂ , Xe, Kr It is desirable to perform dry etching using at least one gas selected from O ₂ . More preferably, the reducing plasma includes atoms or molecules containing at least one element selected from carbon, hydrogen, nitrogen, sulfur, iodine, chlorine, and bromine. More preferably, the plasma containing the reducing molecule or atom contains at least one molecule selected from carbon monoxide, hydrogen, nitric oxide, sulfur monoxide, iodine, chlorine, bromine, Preference is given to containing carbon monoxide or hydrogen. In particular, it should be noted that it is not necessary to supply these molecules in the form of a gas. For example, when an oxide is processed using the etching gas CHF ₃ as a plasma generation gas, that is, when plasma processing is performed using CHF ₃ plasma, carbon monoxide may exist under normal conditions. It is clear. This is because the oxide oxygen and the carbon of CHF ₃ react to generate carbon monoxide, and the present invention uses the molecules generated in the plasma processing process and present in the plasma as described above. It is also effective.

  Here, when the electrode film is a metal, it becomes a metal-rich film by processing using reducing plasma, and can be easily etched by argon ions, so that it can be easily etched without increasing the temperature. It becomes possible. For example, a metal oxide film such as ITO becomes a metal-rich film by reducing plasma such as hydrogen plasma and is easily removed by argon ions.

Further, when performing dry etching using at least one gas selected from HCl, HBr, HI, CH ₄ , CH ₃ OH, Ar, N ₂ , and O ₂ , which is one of the present invention, reducing plasma That is, the method of treating with plasma containing reducing molecules or atoms can maintain an etching rate that cannot be achieved at a substrate temperature of 150 ° C. or lower, and contributes to improving the durability of a functional element containing an organic semiconductor. I found out that The dry etching method in the present invention is considered to have the same effect that can be obtained by any method regardless of inductive coupling type or capacitive coupling type.

  In the above description, the example in which one counter electrode film is stacked on the photoelectric conversion film has been described. However, the counter electrode film may have a two-layer structure. In this case, for example, as shown in FIG. 3, the counter electrode film 25 has a two-layer structure of a first counter electrode film 31 and a second counter electrode film 32 stacked on the first counter electrode film 31. Etching may be performed by changing the etching rate between the first counter electrode film 31 and the second counter electrode film 32. Hereinafter, the patterning process of the counter electrode film having the structure shown in FIG. 3 will be described.

FIG. 3 is a diagram for explaining the patterning process of the counter electrode film of the photoelectric conversion film laminated image sensor of the present embodiment.
First, after the first counter electrode film 31 is formed on the photoelectric conversion film 24 and the second counter electrode film 32 is formed on the first counter electrode film 31, the patterning process is started. In the patterning process, the hard mask 30 is formed on the second counter electrode film 32 with a material containing at least one of SiO ₂ and SiNx (FIG. 3A), and the process proceeds to the etching process. Here, the thickness of the first counter electrode film 31 is, for example, 10 nm. The thickness of the second counter electrode film 32 is, for example, 0.15 μm. The material of the first counter electrode film 31 can be the same as the material of the counter electrode film 25, but a halogen-based etchant, that is, an etchant containing Cl, Br, I (for example, HCl, HBr, HI, A material resistant to BCl ₃ , Cl _2, etc.) is preferable. Examples of such a material include In, W, TaN, Nb, Pt, Ga, TiN, and ZrN. Particularly preferred materials are at least one selected from In, W, TaN, Nb, Pt, and Ga. One material. As the material of the second counter electrode film 32, the same material as that of the counter electrode film 25 can be used. The light transmittance when the first counter electrode film 31 and the second counter electrode film 32 are laminated is preferably 60% to 98%, and more preferably 80% to 98%.

  In the etching step, for example, only the etchant gas type is variable, the other conditions are the same, the first etchant gas is used, and the second counter electrode film 32 is changed to the first counter electrode film 31 at the first etching rate. A high-speed etching process is performed to etch the surface (FIG. 3B), and simultaneously with the completion of the high-speed etching process, the first etchant gas is switched to the second etchant gas, and the second etchant gas is used to A low-speed etching process is performed in which the second counter electrode film 32 is etched to the surface of the blue detection photoelectric conversion film 24 at an etching rate of 2 (FIG. 3B), and the etching process is terminated.

  In this etching step, the first etchant gas type is determined in advance so that the etching rate in the high-speed etching step becomes the first etching rate, and the etching rate in the low-speed etching step becomes the second etching rate. Thus, the second etchant gas type may be determined in advance. Thus, by making the counter electrode film have a two-layer structure, the etching rate can be easily switched, and the manufacturing process can be simplified.

The first etchant gas may be any gas used for dry etching, but is preferably any of Hl, HBr, HCl, CH ₄ , CH ₃ OH, etc., or at least 2 selected from these gases. A gas mixture of two gases is used. The second etchant gas may be any gas used for dry etching, but is preferably any one of CH ₄ , CH ₃ OH, BCl ₃ , Cl _2, or at least two gases selected from these gases. The mixed gas is used.

  In the patterning process described with reference to FIG. 3, only the etchant gas type is variable, but it is also possible to finely control the etching rate by changing the input power during etching and the pressure in the chamber during etching. It is. Even when the etching conditions (input power, pressure in the chamber, etchant gas type, etc.) are all the same, the etching rate can be increased by combining the materials of the first counter electrode film 31 and the second counter electrode film 32. It is possible to control. In any case, by etching the second counter electrode film 32 at the first etching rate and etching the first counter electrode film 31 at the second etching rate, the photoelectric conversion characteristics of the photoelectric conversion element are deteriorated. Can be prevented.

  The input power during the etching is preferably 100 W or more and 4 kW or less. The pressure in the chamber at the time of etching is preferably 0.01 Pa or more and 50 Pa or less.

  Further, the patterning step of this embodiment is performed when patterning a translucent electrode laminated on a photoelectric conversion film in a photoelectric conversion element composed of two translucent electrodes and a photoelectric conversion film sandwiched between them. It becomes effective. As used herein, the photoelectric conversion element includes not only one that converts light into electricity but also one that converts electricity into light (for example, an organic EL element). That is, the patterning process of the present embodiment can be applied to a manufacturing process of an organic EL display element and the like in addition to the photoelectric conversion film stacked solid-state imaging element.

  As described above, according to the method of the present invention, it is possible to perform patterning of electrodes without causing deterioration of element characteristics. Therefore, the method can be applied to formation of various functional elements such as a stacked solid-state imaging element. It is.

2 is a schematic cross-sectional view of two pixels of a photoelectric conversion film stacked solid-state imaging device according to an embodiment of the present invention. The figure for demonstrating the patterning process of a counter electrode film The figure for demonstrating the patterning process of a counter electrode film

Explanation of symbols

1 P-well layers 2, 4, 6 High-concentration impurity regions 3, 5, 7 MOS circuit 8 Gate insulating film 9, 10 Insulating films 12, 15, 17, 20, 22, 25 Translucent electrode films 13, 18, 23 Electrodes 14, 19, 24 Photoelectric conversion film 25 Translucent insulating film 26 Light shielding film

Claims (28)

A method for producing a functional element comprising a translucent electrode film on a layer containing an organic material as a functional layer,
Patterning process of the light transmitting electrode layer is observed containing a fast etching step of etching the light transmitting electrode layer at 10 nm / min or more etch rate,
The high-speed etching step ends the etching leaving a predetermined amount of the translucent electrode,
The patterning step includes, after the high-speed etching step, a low-speed etching step of etching the remaining transparent electrode at a rate lower than the etching rate of the high-speed etching step.
Prior to the low-speed etching step, the step of processing with reducing plasma;
After treatment with the reducing plasma method of including functional element and performing etching by irradiation with argon ions. It is a manufacturing method of the functional element according to claim 1,
A function in which an etchant gas used in the high-speed etching process includes at least one of hydrogen iodide (HI), hydrogen bromide (HBr), hydrogen chloride (HCl), methane (CH ₄ ), and methanol (CH ₃ OH). Device manufacturing method. A method for producing a functional element according to claim 1 or 2,
The translucent electrode is a method of manufacturing a functional element including at least one of indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), ATO, zinc oxide (ZnO), and FTO. A method for manufacturing a functional device according to any one of claims 1 to 3 ,
A method of manufacturing a functional element, wherein an etchant gas used in the low-speed etching step includes at least one of HI, HBr, HCl, CH ₄ , CH ₃ OH, boron chloride (BCl ₃ ), and chlorine (Cl ₂ ) . A method for producing a functional element according to any one of claims 1 to 4 ,
The translucent electrode is composed of a first translucent electrode and a second translucent electrode laminated on the first translucent electrode,
A method for manufacturing a functional element , wherein the second translucent electrode is etched in the high-speed etching step, and the first translucent electrode is etched in the low-speed etching step . A method for producing a functional element according to claim 5,
The first translucent electrode is a method of manufacturing a functional element made of a material having etching resistance to an etchant containing halogen . A method for manufacturing a functional element according to any one of claims 1 to 6 ,
The reducing plasma contains at least one element selected from carbon (C), hydrogen (H), nitrogen (N), sulfur (S), iodine (I), chlorine (Cl), and bromine (Br). A method for producing a functional element containing an atom or molecule . A method for manufacturing a functional element according to any one of claims 1 to 6 ,
The reducing plasma includes carbon monoxide (CO), hydrogen (H ₂ ), nitrogen monoxide (NO), sulfur monoxide (SO), iodine (I ₂ ), chlorine (Cl ₂ ), bromine (Br ₂ ). A method for producing a functional device comprising at least one molecule selected from the group consisting of: It is a manufacturing method of the functional element according to claim 5 or 6 ,
The second translucent electrode includes at least one of ITO, IZO, SnO ₂ , ATO, ZnO, and FTO,
The first translucent electrode is a functional element including at least one of indium (In), tungsten (W), tantalum nitride (TaN), niobium (Nb), platinum (Pt), and gallium (Ga) . Production method. A method for manufacturing a functional element according to any one of claims 1 to 9 ,
The manufacturing method of the functional element whose input electric power at the time of the said etching is 100 W or more and 4 kW or less . A method for manufacturing a functional element according to any one of claims 1 to 10 ,
A method for manufacturing a functional element, wherein the pressure in the chamber during the etching is 0.01 Pa or more and 50 Pa or less . A method for manufacturing a functional element according to any one of claims 1 to 11 ,
In the patterning step, a functional element manufacturing method using a hard mask including at least one of silicon oxide (SiO ₂ ) and silicon nitride (SiN _x ) . A method for manufacturing a solid-state imaging device, comprising: a substrate on which a signal readout circuit is formed; a photoelectric conversion film including an organic material stacked on the substrate; and a functional element including a translucent electrode stacked on the photoelectric conversion film. Because
  The manufacturing method of the solid-state image sensor which produces the said functional element with the manufacturing method of any one of Claims 1 thru | or 12.   A method for producing a functional element comprising a translucent electrode film on a layer containing an organic material as a functional layer,
  The patterning step of the translucent electrode film includes a high-speed etching step of etching the translucent electrode film at an etching rate of 10 nm / min or more,
  In the patterning step, silicon oxide (SiO ₂ ) And silicon nitride (SiN) _x ) Using a hard mask including at least one of the following.   A method for producing a functional element according to claim 14,
  Etchant gas used for the high-speed etching process is hydrogen iodide (HI), hydrogen bromide (HBr), hydrogen chloride (HCl), methane (CH ₄ ), And methanol (CH ₃ OH) at least one of the functional elements.   A method for producing a functional element according to claim 14 or 15,
  The translucent electrode includes indium tin oxide (ITO), indium zinc oxide (IZO), and tin oxide (SnO). ₂ ), ATO, zinc oxide (ZnO), and a method for producing a functional element including at least one of FTO.   A method for manufacturing a functional element according to any one of claims 14 to 16,
  The high-speed etching step ends the etching leaving a predetermined amount of the translucent electrode,
  The said patterning process is a manufacturing method of a functional element including the low-speed etching process of etching the remaining said translucent electrode at a speed | rate lower than the said etching speed of the said high-speed etching process after the said high-speed etching process.   A method for producing a functional element according to claim 17,
  Etchant gas used in the low-speed etching process is HI, HBr, HCl, CH ₄ , CH ₃ OH, boron chloride (BCl ₃ ), And chlorine (Cl ₂ ). The manufacturing method of the functional element containing at least one.   A method for producing a functional element according to claim 17 or 18,
  Prior to the low-speed etching step, a functional element manufacturing method including a step of processing with reducing plasma.   It is a manufacturing method of the functional element according to claim 19,
  The reducing plasma contains at least one element selected from carbon (C), hydrogen (H), nitrogen (N), sulfur (S), iodine (I), chlorine (Cl), and bromine (Br). A method for producing a functional element containing an atom or molecule.   It is a manufacturing method of the functional element according to claim 19,
  The reducing plasma is composed of carbon monoxide (CO), hydrogen (H ₂ ), Nitric oxide (NO), sulfur monoxide (SO), iodine (I ₂ ), Chlorine (Cl ₂ ), Bromine (Br ₂ ). A method for producing a functional device containing at least one molecule selected from the group consisting of   It is a manufacturing method of the functional element according to claim 19,
  A method for manufacturing a functional element, comprising a step of performing etching by irradiating argon ions after the treatment with the reducing plasma.   A method for manufacturing a functional element according to any one of claims 17 to 22,
  The translucent electrode is composed of a first translucent electrode and a second translucent electrode laminated on the first translucent electrode,
  A method of manufacturing a functional element, wherein the second translucent electrode is etched in the high-speed etching step, and the first translucent electrode is etched in the low-speed etching step.   A method of manufacturing a functional element according to claim 23,
  The first translucent electrode is a method of manufacturing a functional element made of a material having etching resistance to an etchant containing halogen.   A method for producing a functional element according to claim 23 or 24,
  The second translucent electrode is made of ITO, IZO, SnO. ₂ , ATO, ZnO, and FTO,
  The first translucent electrode is a functional element including at least one of indium (In), tungsten (W), tantalum nitride (TaN), niobium (Nb), platinum (Pt), and gallium (Ga). Production method.   A method for manufacturing a functional element according to any one of claims 14 to 25, wherein:
  The manufacturing method of the functional element whose input electric power at the time of the said etching is 100 W or more and 4 kW or less.   A method for manufacturing a functional element according to any one of claims 14 to 26,
  A method for manufacturing a functional element, wherein the pressure in the chamber during the etching is 0.01 Pa or more and 50 Pa or less. A method for manufacturing a solid-state imaging device, comprising: a substrate on which a signal readout circuit is formed; a photoelectric conversion film including an organic material stacked on the substrate; and a functional element including a translucent electrode stacked on the photoelectric conversion film. Because
  A method for manufacturing a solid-state imaging device, wherein the functional element is manufactured by the manufacturing method according to any one of claims 14 to 27.

Images