JP5153598B2 - Manufacturing method of color filter - Google Patents

Description

The present invention, on the boundary of the different colored layers of the color filter array two or more colors of the colored layer is arranged on the support relates to the method of manufacturing a color filter comprising forming a black matrix.

  In recent years, in the solid-state imaging device, an increase in the number of imaging pixels has been remarkable, and accordingly, the effective pixel area having the same size as the conventional one has been reduced in area per pixel, and at present, the pixel size is 1.7 μm. Solid-state imaging devices are built into digital cameras and molded telephones with cameras. As the area of the pixel size is reduced, the color filters provided in the solid-state imaging device maintain the color separation performance because the color mixture between the pixels becomes remarkable as the area of the light receiving part is reduced. It is requested. As a method for producing a color filter, a photolithography method and a dry etching method are widely known.

  In the photolithography method, since the manufacturing process conforms to the photolithography process of semiconductor manufacturing, initial investment can be suppressed. Thus, conventionally, it has been widely used as a method for producing a color filter. In this color filter manufacturing method using the photolithographic method, a coating film formed by applying a radiation-sensitive composition such as a colored curable composition on a substrate and drying it is colored by pattern exposure, development and baking. Pixels are formed and this operation is repeated for each color to produce a color filter.

  On the other hand, a dry etching method is used as a method effective for forming a fine pattern with a thinner film than a color filter manufacturing method using a photolithography method. The dry etching method has been conventionally employed as a method for forming a pattern on a dye-deposited thin film (see, for example, Patent Document 1), and the thin film formation has a film thickness while maintaining the same spectral characteristics as compared to a photolithography system. However, it is possible to form a thin film having a thickness of 1/2 or less. In addition, a pattern forming method combining a photolithography method and a dry etching method has been proposed (see, for example, Patent Document 2).

  In addition, a color filter material (colorant-containing composition) different from the first color is applied on the first color filter (colored layer) patterned by the dry etching method, so that the second color filter (Colored layer) is formed, and the surface of the second color filter is flattened using the CMP (Chemical Mechanical Polishing) method or the etch-back method, and the second color is placed in the gap between the first color filters. A method for arranging color filters has been proposed (see, for example, Patent Document 3).

  Furthermore, since the performance of the color filter is related to maintaining the important characteristics of the solid-state imaging device, various performance improvements such as thinning and rectangularization, and prevention of color mixture between pixels (overlapping colors overlap each other) are required. Yes.

As a measure against the performance requirement of the color filter, in Patent Document 4, a filter separation layer for separating the color filters from each other is formed on a support, and then the color filter is formed on the filter separation layer by dry etching. There has been proposed a method of manufacturing a color filter by opening a region and embedding a colored layer, and removing a colored layer other than the region embedded in the opening by a planarization process such as CMP (Chemical Mechanical Polishing).
JP-A-55-146406 JP 2001-249218 A JP 2006-351786 A JP 2006-351775 A

  In the manufacturing method described in Patent Document 4, a filter separation layer is formed from a material having a refractive index different from that of the color filter layer, and incident light from an oblique direction is reflected by a difference in refractive index between the color filter and the filter separation layer. However, there are cases where the reflection efficiency is poor and the color mixing suppression effect cannot be sufficiently obtained. Therefore, in order to increase the coloring effect and contrast of color filters in liquid crystal displays and plasma displays, a light-blocking black matrix (light-shielding wall) formed at the boundary between the three-color filters is used for the color of the solid-state imaging device. It is considered to be applied to a filter. As a conventional method for forming a light-shielding wall, a photoresist layer is formed on a color filter array in which colored layers are arranged, and a pattern that matches the boundary line of the colored layer is formed using an i-line exposure stepper. An opening for a light shielding wall is formed in the color filter array using the photoresist layer as a mask. Then, a black matrix (light shielding wall) is formed by embedding a composition containing a black colorant in the opening for the light shielding wall.

  When such a black matrix is formed, a line width larger than 0.5 μm is obtained in pattern formation using an i-line exposure stepper used in a conventional manufacturing process. However, in order to satisfy the required performance while accommodating further miniaturization of the color filter, the light shielding wall must be formed with a line width of 0.5 μm or less, which is narrower than before. Therefore, it is conceivable to use a KrF exposure stepper that can form a pattern with a narrower line width. However, if a KrF exposure stepper is used instead of the i-line exposure stepper, the cost of capital investment increases, which causes an increase in the cost of the product itself. It becomes.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a color filter manufacturing method capable of further miniaturizing a light shielding wall at a low cost.

In the method for producing a color filter of the present invention, a black color comprising a composition in which a colored layer of at least two colors is arranged on a support and a black colorant is dispersed at a location aligned with the boundary of the colored layer. a method of manufacturing a color filter formed by arranging a light-shielding layer, and the black shielding layer forming step of forming the black shielding light layer on the support, by dry etching, shifting the adjacent arrangement with each other a predetermined pitch checkered a first opening forming an etching step for forming a first opening pattern shape of the black shielding light layer, wherein the predetermined pitch position shifted checkerboard pattern of the second to the first opening an opening formed in the black shielding light layer, and having at least a second opening forming an etching step for forming a black matrix, leaving a portion matching the boundary of the colored layer.

A color filter in which a colored layer of at least two colors is arranged on a support, and a black light-shielding layer made of a composition in which a black colorant is dispersed is arranged at a position aligned with the boundary of the colored layer. A manufacturing method comprising: forming a black light shielding layer comprising a composition in which a black colorant is dispersed on the support layer; and forming a first photoresist layer on the black light shielding layer. A first patterning step of forming a first pattern of a checkered pattern in which adjacent arrays are shifted by a predetermined pitch, and a dry etching process to form a checkered pattern using the first photoresist layer as a mask a first opening forming an etching step for forming the first opening, forming a second photoresist layer so as to fill the black shielding light layer and said first opening, said first opening For the department A second patterning step of forming a checkered second pattern at a position shifted by the predetermined pitch, and a dry etching process, the second photoresist layer as a mask with respect to the first opening. At least a second opening formation etching step of forming a checkered pattern-like second opening at a position shifted by a predetermined pitch and forming a black matrix leaving a portion that matches the boundary of the colored layer. It is characterized by.

The black colorant is preferably titanium black. The dry etching process preferably uses a mixed gas containing at least a fluorocarbon gas and an oxygen gas.

According to the present invention, the checkered pattern-like first openings that are shifted from each other by a predetermined pitch, and the checkered pattern-like second openings that are shifted by a predetermined pitch with respect to the first openings. Since a black matrix (light-shielding wall) is formed by leaving a portion that is formed and aligned with the boundary of the colored layer, a method for manufacturing a color filter that can reduce costs while forming a black matrix with a fine line width it is possible to provide a.

  Hereinafter, the present invention will be specifically described with reference to the accompanying drawings. In FIG. 1, a solid-state imaging device 10 according to the present embodiment includes a semiconductor substrate 12 including photodiodes 11R, 11G, and 11B, and a color filter provided on the incident side of the semiconductor substrate 12 with respect to the photodiodes 11R, 11G, and 11B. 13R, 13G, 13B and the color filters 13R, 13G, 13B, which are formed at the boundaries between the respective color filters, isolate each other from each other, and the color filters 13R, 13G, 13B and the light shielding wall 14 are covered and flattened. And a microlens 16 provided on the planarization layer 15 so as to correspond to the formation regions of the color filters 13R, 13G, and 13B. The color filters 13R, 13G, and 13B transmit red, green, and blue light, respectively. Furthermore, the semiconductor substrate 12 is provided with a light shielding film (not shown) that is open only in the portions of the photodiodes 11R, 11G, and 11B, and this light shielding film is formed of tungsten or the like.

  FIG. 2 is a plan view of the solid-state imaging device 10 as viewed from above the semiconductor substrate (normal direction), and broken lines indicate boundaries between the color filters 13R, 13G, and 13B. In the solid-state imaging device 10, the color filters 13R, 13G, and 13B constituting the pixels and the corresponding photodiodes 11R, 11G, and 11B are arranged in a Bayer array, that is, the odd lines are repeated of the color filters 13G and 13R, and the even lines are colored. The filters 13B and 13G are arranged repeatedly. Light that has entered the photodiodes 11R, 11G, and 11B through the microlens 16 and the color filters 13R, 13G, and 13B is generated and stored as signal charges corresponding to the light amounts of the respective colors by photoelectric conversion.

  The light shielding wall 14 isolates the color filters 13R, 13G, and 13B from each other, and therefore absorbs obliquely incident light among the light that has entered through the microlens 16 and the color filters 13R, 13G, and 13B. Light leakage (color mixing) is prevented from passing through the lens 16 and the planarization layer 15 to adjacent pixels.

  The light shielding wall 14 is made of a black material-containing composition that absorbs visible light, and absorbs light when oblique light is incident. As will be described later, the light shielding wall 14 is formed by dry etching so that the wall surface thereof is substantially parallel to the normal direction of the semiconductor substrate 12.

  The solid-state imaging device generally has a form in which a microlens is provided in addition to the color filter. However, for example, a configuration in which a microlens is not provided by providing a photoelectric conversion layer as a lower layer of the color filter layer may be employed. In this case, examples of the photoelectric conversion layer include an MCP (microchannel plate) and an ITO (Indium Tin Oxide) film.

  The black matrix (light shielding wall) 14 of the solid-state imaging device 10 to which the present invention is applied has a pixel pitch of the color filters 5R, 5G, and 5B as P, and a line width of the black matrix 6 in the pixel direction orthogonal to the film thickness direction as D. Then, it is preferable to form so that it may become D = (1/5-1/15) P, and it is preferable to form by D = (1/7-1/10) P from a light-shielding viewpoint. The film thickness of the black matrix 6 is preferably the same as that of the color filter layer from the viewpoint of the flatness of the color filter.

  Such a color filter constituting the solid-state imaging device 10 is particularly suitable when manufactured by applying a dry etching method. Hereinafter, a method for producing a color filter according to the present invention will be described in detail.

  As shown in FIG. 3, the color filter manufacturing process 19 includes a black matrix forming process 20, a first color filter forming process 21, a second color filter forming process 22, and a third color filter forming process 23. Further, the black matrix forming step 20 includes an etching stopper layer forming step 24, a black light shielding layer forming step 25, a first patterning step 26, a first etching step 27 (first opening forming etching step), and a first photo process. It comprises a resist removal step 28, a second patterning step 29, a second etching step 30 (first opening formation etching step), and a second photoresist removal step 31.

  On the other hand, the first to third color filter forming steps 21 to 23 include patterning steps 34 and 39, etching steps 35 and 40, photoresist removing steps 36 and 41, colored layer forming steps 32, 37 and 42, and a planarizing step 33. , 38, 43. Note that the first color filter forming step 21 does not include a patterning step, an etching step, and a photoresist removing step.

  In the case of the solid-state imaging device 10, there is a step of forming the semiconductor substrate 12 as a support body before these steps 20 to 23, and after these steps, the planarization layer 15 covering the color filters 13B and 13G. And at least a step of forming a microlens 16 disposed on the planarizing layer 15.

  The color filter manufacturing process 19 starts from a black matrix forming process 20. In the black matrix forming step 20, first, an etching stopper layer forming step 24 is performed. The etching stopper layer forming step 24 plays a role of suppressing damage to the support 44 described later, and is removed from the composition containing silicon oxide in the present invention from the viewpoint of being removed after the black matrix (light-shielding wall) is formed. A layer is formed, for example, 4MS (manufactured by Lhasa Kogyo Co., Ltd.) is applied onto the support 44 using a spin coater (SCWC80A manufactured by Dainippon Screen Co., Ltd.), and then the ambient temperature is 200 ° C. to 200 ° C. The coating film is dried and cured at 250 ° C. for 5 to 10 minutes to form an etching stopper layer 45 (see FIG. 4), and a black light shielding layer 46 to be described later is formed on the etching stopper layer 45. The film thickness of the etching stopper layer 45 is formed within a range of 50 to 200 mm, and more preferably within a range of 70 to 150 mm. Note that not limited to the spin coating method, a CVD method, a sputtering method, a vapor deposition method, or a sol-gel method may be used. In addition to forming the etching stopper layer, OCD Type-12 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) or CERAMATE-LNT (manufactured by Catalyst Kasei Kogyo Co., Ltd.) may be used.

[Black shading layer forming step]
After the etching stopper layer forming step 24, a black light shielding layer forming step 25 is performed. In the black light-shielding layer forming step 25, as shown in FIG. 4, a composition in which a black colorant for forming the black light-shielding layer 46 is dispersed on a support 44 using a spin coater (SCWC80A manufactured by Dainippon Screen). Apply the object. Next, using a hot plate, the atmosphere temperature is 200 ° C. to 250 ° C. for 5 to 10 minutes, the coating film is cured, and the black light shielding layer 46 is formed. This heat treatment may be performed simultaneously with the drying after the application of the composition, or a separate thermosetting step may be provided after the application and drying. In the present invention, the composition for forming the black light-shielding layer 46 is preferably one in which a metal pigment is dispersed as a black colorant, and titanium black is particularly preferably used as the metal pigment used as the black colorant.

[Support]
The support 44 used in the present invention may be selected according to the application. For example, when manufacturing a solid-state imaging device, a semiconductor substrate (photoelectric conversion element substrate), for example, a silicon substrate, an oxide film, silicon nitride, or the like In the case of manufacturing a liquid crystal display device, a glass substrate such as soda glass, borosilicate glass, quartz glass, and those obtained by attaching a transparent conductive film thereto can be used. Further, an intermediate layer or the like may be provided between the support and the colored layer as long as the present invention is not impaired.

[I-line photoresist patterning]
Next, a positive photoresist (FHi622BC: manufactured by FUJIFILM Electronics Materials) is applied onto the black light shielding layer 46 using a spin coater. Pre-baking is performed for 60 seconds in the range of 80 to 100 ° C. with a hot plate to form the photoresist layer 47. Subsequently, ultraviolet rays of i-line (wavelength 365 nm) are exposed from above the photoresist layer 47 to the region where the colored layer is formed using a photomask using a stepper. Next, PEB treatment is performed for 90 seconds at 100 to 120 ° C. using a hot plate. Thereafter, paddle development processing is performed with a developer, and post-baking processing is further performed with a hot plate to remove the photoresist in a region where first to third colored layers 70, 74, and 76 to be described later are formed (first 1 patterning step 26). FIG. 5 shows a state where the photoresist in a region where the first to third colored layers 70, 74, and 76 are formed, that is, a position corresponding to the boundary between the first to third colored layers 70, 74, and 76. The reference numeral 48 indicates an opening from which the photoresist is removed. In the first patterning step 26, as shown in FIG. 6, a pattern in which rectangular openings 48 are arranged so as to have a checkered pattern in which adjacent arrays are shifted vertically and horizontally by the pixel pitch P is used. A photoresist layer 47 is formed.

  As the photoresist, a known positive type photoresist can be used. As the positive photoresist, a positive photosensitive resin composition that is sensitive to ultraviolet rays (g rays, i rays), far ultraviolet rays including excimer lasers such as KrF and ArF, and electron beams can be used.

  The light source used for exposure is preferably i-line because the formation of the color filter pattern only needs to have a resolving power of about 1.0 μm. Any developer can be used as long as it does not affect the black light-shielding layer 46 and dissolves the exposed portion of the positive resist and the uncured portion of the negative resist. Specifically, a combination of various organic solvents or an alkaline aqueous solution can be used.

[First etching step]
Next, the first etching step 27 for dry etching using the photoresist layer 47 as a mask will be described. As a dry etching apparatus to be used, a reactive ion etching apparatus (RIE; U-621) manufactured by Hitachi High-Technologies Corporation, or an ICP etcher apparatus using an inductive coupled plasma (ICP) (NE500: ULVAC, Inc.) Are preferably used. The RIE apparatus 49 is a known parallel plate type, capacitive coupling type, or electron cyclotron resonance type, and can perform dry etching using RF, microwave, or VHF discharge. Using this RIE apparatus 49 (see FIG. 7), an etching process is performed in which the black light shielding layer 46 is dry-etched using the photoresist layer 47 as a mask. Thereby, the black light shielding layer 46 in the region where the colored layer is formed is removed. FIG. 8 shows a state where the black light shielding layer 46 is etched by the first etching step 27, and reference numeral 50 denotes an opening of the black light shielding layer 46 removed by the first etching step 27.

  FIG. 7 shows a schematic configuration of a dry etching apparatus. In the present embodiment, various dry etching processes are performed using the RIE apparatus 49. The RIE apparatus 49 includes a chamber 51, a planar electrode (cathode) 52, a counter electrode (anode) 53, an RF oscillator 54, a blocking capacitor 55, an etching gas supply unit 56, and a control unit 57 that controls them. With.

  The chamber 51 is provided with an introduction port 51a through which an etching gas is introduced from the side surface into the inside, and a planar electrode 52 and a counter electrode 53 are arranged inside. The planar electrode 52 and the counter electrode 53 are connected in series with the RF oscillator 54. Further, a blocking capacitor 55 is connected between the planar electrode 52 and the RF oscillator 54, and is connected to the ground 58 between the counter electrode 53 and the RF oscillator 54. The support 44 on which the color filter is formed is set on the planar electrode (cathode) 52.

  In the present invention, in the etching step 27 for dry etching the black light shielding layer 46, as shown in FIG. 9, an opening forming dry etching process 61, a residue removing dry etching process 62, and a lower layer removing dry etching process 63 are sequentially performed. . In the etching step 27, first, an opening forming dry etching process 61 is performed.

[Opening formation dry etching process]
In this opening formation dry etching process 61, from the viewpoint of anisotropic processing of the black light shielding layer 46, CF ₄ gas and CxFy gas (fluorocarbon gas; x = 2 to 6, A mixed gas (first mixed gas) of y = 4 to 8) and oxygen gas is used as an etching gas. From the point of obtaining the etching speed and anisotropic processing, this first mixed gas can be mixed within a range of 2 to 20 for CxFy gas and 1 to 10 for oxygen gas when CF ₄ is 1. preferable. In the opening formation dry etching process 61, the first etching gas is introduced into the chamber 51 in which the support 44 is set on the planar electrode (cathode) 52 using the RIE device 49. When a high frequency voltage is applied between the planar electrode 52 and the counter electrode 53 by the RF oscillator 54 with the first etching gas being introduced, the black light shielding layer 46 is made anisotropic by the cathode effect. Etching is performed.

  When the opening formation dry etching process 61 is applied to the black light shielding layer 46 under the above conditions, the black light shielding layer 46 is not masked by the photoresist layer 47 as shown in FIG. However, since the metal pigment is used as the black colorant as described above, the residue 59 adheres to the inside of the etched opening 50.

[Residue removal dry etching treatment]
In the etching step 27, the opening formation dry etching process 61 described above is performed first, followed by a residue removal dry etching process 62. In the residue removal dry etching process, a mixed gas containing at least oxygen gas is used from the viewpoint of removing the residue 59 attached to the opening 50. As the gas contained in addition to the oxygen gas, an inert gas (a rare gas such as Ar, He, or Xe) or a nitrogen gas is preferable. In the second mixed gas, the mixing ratio of oxygen gas to other gas (oxygen gas / other gas) may be set to 1/1 to 1/4 from the point of obtaining the removal rate of the residue and the etching speed. preferable.

  Under the above conditions, the residue removal dry etching process 62 is performed after the opening formation dry etching process 61, whereby the residue 59 attached to the opening 50 formed in the black light shielding layer 46 by the opening formation dry etching process 62. Is removed by the residue removal dry etching process 62. Therefore, the black light shielding layer 46 is etched with high accuracy with respect to the masking by the photoresist layer 47, and the opening 50 having high rectangularity can be formed.

[Lower layer removal dry etching process]
Following the residue removal dry etching process 62, a lower layer removal dry etching process 63 is performed to remove the etching stopper layer 45 under the black light shielding layer 46. This lower layer removal dry etching process 63 is a CxFy gas (fluorocarbon gas; x = 2-6, y = 4-8) in which the C number is selected from two or more from the viewpoint of removing the silicon oxide layer which is the etching stopper layer 45. ) And oxygen gas (third mixed gas). In the third mixed gas, the mixing ratio of CxFy gas and oxygen gas (CxFy gas / oxygen gas) is set to 1/2 to 5/1 from the viewpoint of obtaining the speed of anisotropic processing and etching. preferable. Under the above conditions, opening formation, residue removal, and lower layer removal dry etching processes 61 to 63 are sequentially performed, so that the opening formation and residue removal dry etching processes 61 and 62 are protected by the etching stopper layer 45. Therefore, it is possible to form the opening 50 by etching with high accuracy without damaging the support 44. After the opening 50 is formed, the etching stopper layer 45 is removed by the lower layer removal dry etching process 63. can do. Reference numeral 60 denotes an opening of the etching stopper layer 45 removed by the lower layer removal dry etching process.

  In this etching step 27, as shown in FIG. 10, openings 50 arranged in a checkered pattern in which adjacent arrays are shifted by the pixel pitch P are formed in the black light shielding layer 46, and the openings 50 have a width. It is formed to have a dimension W. The width dimension W is formed to be slightly smaller than the width dimension P of the pixel pitch. For example, when the pixel pitch P is 1.0 μm, the width dimension W of the opening 50 can be formed to be 0.9 μm.

[Other etching conditions]
As other conditions, the conditions in the etching process vary depending on the material, layer thickness, etc. of the black light shielding layer, but preferable conditions other than the above will be described below.
1) The pressure of the mixed gas in the present invention is preferably 0.1 to 6 Pa.
2) Regarding the relationship between the generated power of the RF oscillator 54, the power applied to the counter electrode, and the power applied to the planar electrode (substrate), the generated power of the RF oscillator / power applied to the planar electrode / planar electrode (substrate) ) The power applied to the substrate is preferably 400 to 800 W / 100 to 500 W / 100 to 800 W, respectively.
3) The temperature of the support is preferably from -5 ° C to 80 ° C.

[First photoresist removal step]
Next to the etching step 27, a photoresist stripping process is performed using a solvent or a photoresist stripper to remove the photoresist layer 47 remaining on the black light shielding layer 46 (first photoresist stripping step). 28). Thereafter, a dehydration bake treatment for solvent removal and dehydration treatment can be performed. As described above, the black light shielding layer 46 in the region where the colored layer is to be formed is removed by etching, and the photoresist layer 47 is peeled off. FIG. 11 shows the shape after stripping the photoresist. It is preferable to include a step of applying a stripping solution or a solvent on the photoresist layer so that the photoresist layer 47 can be removed, and a step of removing the photoresist layer 47 using cleaning water. After the first photoresist removal step 28, a second patterning step 29 is performed.

[Second patterning step]
In the second patterning step 29, as shown in FIG. 12, a photoresist layer 65 is formed on the black light shielding layer 46 and so as to fill the opening 50, and as shown in FIGS. The photoresist layer 65 is formed so as to form a new checkered array opening 66 located in the middle of the opening 50 in an array shifted by the pixel pitch P with respect to the checkered array opening 50 formed in the above. Patterning is performed (patterning step 29). The conditions for forming the photoresist layer 65 and the patterning conditions are the same as in the patterning step 26.

[Second etching step]
Then, after the patterning step 29, an etching step 30 is performed for dry etching using the photoresist layer 65 as a mask. In this etching process 30, as shown in FIG. 15, the opening formation dry etching process, the residue removal dry etching process, and the lower layer removal dry etching process are sequentially performed as in the etching process 27 described above. That is, by the opening formation dry etching process, the black light shielding layer 46 is formed with an opening 67 in a portion not masked by the photoresist layer 65, and a residue 68 is formed in the etched portion (FIG. 15). (State shown in FIG. 15A), by performing the residue removal dry etching process after the opening forming dry etching process, the residue 68 attached to the opening 67 is removed (state shown in FIG. 15B), and the lower layer The etching stopper layer 45 is removed by the removal dry etching process (the state shown in FIG. 15C). Reference numeral 69 denotes an opening of the etching stopper layer 45 that is removed together with the black light shielding layer 46 in the etching step 30. The openings 67 formed in the etching step 30 are formed in a checkered pattern located in the middle of the openings 50 in an arrangement shifted by the pixel pitch P from the openings 50 formed in the etching step 27 described above. And the same width W as the opening 50 is formed. As a result, as shown in FIG. 16, the black light shielding layer 46 is in a state where the openings 50 and 67 are formed in the region where the colored layer is formed, that is, a location corresponding to the boundary between the first to third colored layers. Will be left. Note that after the etching step 30, the photoresist layer 65 remaining on the black light shielding layer 46 and in the opening 50 is removed in a second photoresist removing step 31. FIG. 17 shows the shape after stripping the photoresist.

[First color filter forming step]
After the photoresist removing step 31, first to third color filter forming steps 21 to 23 are sequentially performed. In the first color filter forming step 21, first, a first colored layer forming step 32 is performed. Similar to the method for forming the black light shielding layer 46, a spin coater is used to contain a colorant colored in the first color (for example, green (G)) so as to fill the entire black light shielding layer 46 and the openings 50 and 67. Apply the composition. Next, post baking is performed using a hot plate to form the first colored layer 70 (state shown in FIG. 18).

[Planarization process]
Next, as shown in FIG. 19, an anisotropic etching process is performed using a mixed gas (etching gas) obtained by mixing at least oxygen gas and nitrogen gas until the black light shielding layer 46 is exposed. The colored layer 70 is flattened by an overall etching (etchback) process (flattening step 33). Since the black light shielding layer 46 is formed in advance so as to have the same thickness as that of the first colored layer 70, when the first colored layer 70 is planarized until the black light shielding layer 46 is exposed, One colored layer 70 can be formed to a set film thickness.

[Etch back condition]
As the dry etching apparatus used in the planarization step 33, it is preferable to use the RIE apparatus 49 or the above-described ICP etcher apparatus. In addition, the entire first colored layer 70 is etched (etched back) under etching conditions set in advance using a mixed gas (plasma gas) containing either fluorocarbon gas or chlorine gas. Then, the etch-back process is completed at the point where the surface of the black light shielding layer 46 is exposed and the film thickness of the first colored layer 70 and the black light shielding layer 46 is uniform.

  The planarization step 33 is not limited to this, and a chemical mechanical polishing method (CMP method) may be used. A slurry in which silica fine particles are dispersed is used as an abrasive, and a slurry flow rate is 100 to 250 ml / min, a wafer pressure is 0.2 to 5.0 psi, and a wafer and polishing pad rotational speed is 50 to 300 rpm. , Retainer ring pressure: 1.0 to 2.5 psi, an apparatus comprising an abrasive cloth can be used. After the polishing is completed, pure water cleaning and dehydration baking are performed, so that influences such as application failure and peeling in the next process can be eliminated.

[Second color filter forming step]
In the second color filter forming step 21, first, a photoresist layer 71 (see FIG. 20) is formed on the entire black light shielding layer 46 and the first colored layer 70. Next, by using a photomask of an exposure machine, a region where the second colored layer 74 (second color; for example, blue (B); see FIG. 23) is to be formed is patterned to remove the photoresist ( Patterning step 34). FIG. 21 shows a state in which this patterning step 34 is performed, and reference numeral 72 denotes an opening of the photoresist layer 71 formed by patterning.

  And the etching process 35 which removes the area | region where the 2nd colored layer 74 should be formed is performed. Reference numeral 73 in FIG. 22 is an opening of the first colored layer 70 removed by etching. Following the etching step 35, the remaining photoresist layer 71 is removed (photoresist removal step 36).

  After the photoresist removal step 36, as shown in FIG. 23, the second colored layer 74 (the first colored layer 74) is formed so as to cover the entire black light shielding layer 46 and the first colored layer 70 and to be embedded in the opening 73. Second color; for example, blue (B)) is formed (colored layer forming step 37). Next, as shown in FIG. 24, the entire surface of the second colored layer 74 is flattened until the black light shielding layer 46 and the first colored layer 70 are exposed by the same method as in the flattening step 33 (flattening). Step 38). After the flattening step 38, a third color filter forming step 23 is subsequently performed.

[Third color filter forming step]
In the third color filter forming step 23, a patterning step 39, an etching step 40, a photoresist removing step 41, a colored layer forming step 42, and a flattening step 43 similar to the second color filter forming step 22 described above are performed. First, a photoresist layer (not shown) is formed over the black light shielding layer 46 and the first and second colored layers 70 and 74. Next, by using a photomask, the region where the third colored layer 76 (third color; for example, red (R); see FIG. 25) is to be formed is patterned to remove the photoresist (patterning step 39). ). And the etching process 40 which removes the area | region which is going to form the 3rd colored layer 76 is performed. Reference numeral 75 in FIG. 25 denotes an opening of the first and second colored layers 70 and 74 removed by etching.

  The etching process 40 is followed by a photoresist layer removing process (photoresist removing process 41). The photoresist removing process 41 is followed by covering the entire upper surfaces of the first and second colored layers 70 and 74 and opening portions. A third colored layer (third color; for example, red (R)) 76 is formed so as to be embedded in 75 (colored layer forming step 42). Next, as shown in FIG. 25, the third colored layer 76 is flattened until the first and second colored layers 70 and 74 are exposed (flattening step 43). Through the above steps, a color filter in which the first to third colored layers 70, 74, and 76 are arranged and the black light-shielding layer 46 is formed at a location that becomes a boundary line is manufactured.

  As described above, in the color filter manufacturing process 20, the first etching process 27 for forming the checkered pattern-like openings 50 in which adjacent arrays are shifted by a predetermined pitch, and the openings 50 by a predetermined pitch. Since the second etching process 30 for forming the black matrix (light-shielding wall) in which the checkered pattern-like openings 67 are formed in the shifted arrangement and the portions aligned with the boundary of the colored layer are left is performed. For example, when the pixel pitch P is 1.0 μm and the width dimension W of the openings 50 and 67 is 0.9 μm, the black matrix line width D may be formed to 0.1 μm. it can.

  Moreover, in the said embodiment, in the color filter array formation process (color filter formation processes 21-23), although the color filter array is formed using the dry etching method, not only this but using the photolitho method, Specifically, Japanese Patent Application 2006-196622, Japanese Patent Application 2006-283454, Japanese Patent Application 2007-011291, Japanese Patent Application 2006-284363, Japanese Patent Application 2006-350428, Japanese Patent Application 2006-346108, Japanese Patent Application 2006-350429, Japanese Patent Application 2007. -033576. It is preferable to form from the photosensitive composition described in these prior patent documents, or a thermosetting composition using the method described in 1).

  In the above embodiment, the black light shielding layer opening is formed, the opening residue is removed, and the etching stopper layer is removed by performing the etching process three times for each etching step. However, the present invention is not limited to this, and it is also possible to simultaneously remove the residue of the opening and the etching stopper layer in one etching process and omit one etching process. In this case, the opening formation dry etching process is performed in the same manner as in the above embodiment, and the third mixed gas, that is, the C number is selected from 2 or more as the etching gas used in the dry etching process for residue removal and lower layer removal. A mixed gas of CxFy gas (fluorocarbon gas; x = 2 to 6, y = 4 to 8) and oxygen gas is used. The mixing ratio is the same as that of the third mixed gas described above. By using this third mixed gas, it is possible to remove the residue formed in the opening of the black light-shielding layer and the etching stopper layer at the same time by the etching process of residue removal and lower layer removal, with high accuracy. A black matrix can be formed.

[Black material-containing composition]
(1) Composition The composition of the present invention is a colorant containing (A) a colorant, (B) a thermosetting compound, and (C) an organic solvent. In addition to the above (A) to (C), other components may be contained as additives.

Examples of (A) include the following colorants.
(A) Titanium black The present invention contains titanium black as a black colorant.
Titanium black has a higher light shielding ability in the infrared region than conventional pigments and dyes dispersed and dissolved in photosensitive resin compositions, particularly photosensitive resin compositions for light shielding films. The infrared light region can be surely shielded, which cannot be shielded by combination. In particular, the light-shielding film obtained by curing the photosensitive resin composition of the present invention has a high light-shielding property in the infrared light region, and can suppress noise due to dark current of a solid-state imaging device having the light-shielding film. Titanium black can be cured with a small amount of exposure because it absorbs less i-rays for pattern formation than carbon black commonly used as a black colorant. It can contribute to improvement.

  Titanium black is black particles having titanium atoms. Preferred are low-order titanium oxide and titanium oxynitride. The surface of the titanium black particles can be chemically modified as necessary for the purpose of improving dispersibility and suppressing aggregation. Specifically, the surface of titanium black can be coated with silicon oxide, titanium oxide, germanium oxide, aluminum oxide, magnesium oxide, zirconium oxide, and as disclosed in Japanese Patent Application Laid-Open No. 2007-302836. Surface treatment with a water repellent material is also possible. In addition, the titanium black is a composite oxide such as Cu, Fe, Mn, V, and Ni, and a black pigment such as cobalt oxide, iron oxide, carbon black, and aniline black for the purpose of adjusting dispersibility, colorability, and the like. You may contain 1 type or in combination of 2 or more types. In addition, for the purpose of controlling the light-shielding property of a desired wavelength, it is also possible to add existing colorants such as pigments such as red, blue, green, yellow, cyan, magenta, violet, orange, or dyes. .

  Examples of commercially available titanium black products include Gemco Corporation (sold by Mitsubishi Materials Corporation) Titanium Black 10S, 12S, 13R, 13M, 13M-C, 13R, 13R-N, and Ako Kasei Co., Ltd. Tilac D etc. are mentioned.

  The titanium black can be produced by heating a mixture of titanium dioxide and titanium metal in a reducing atmosphere for reduction (Japanese Patent Laid-Open No. 49-5432), ultrafine obtained by high-temperature hydrolysis of titanium tetrachloride. A method of reducing titanium dioxide in a reducing atmosphere containing hydrogen (Japanese Patent Laid-Open No. 57-205322), a method of reducing titanium dioxide or titanium hydroxide at high temperature in the presence of ammonia (Japanese Patent Laid-Open No. 60-65069, No. 61-201610), a method in which a vanadium compound is attached to titanium dioxide or titanium hydroxide and reduced at high temperature in the presence of ammonia (Japanese Patent Laid-Open No. 61-201610). It is not a thing.

  The particle size of the titanium black particles is not particularly limited, but the average particle size (average primary particle size) is 10 to 150 nm from the viewpoints of dispersibility and colorability and the influence on the yield in a solid-state imaging device. It is preferable that it is, and it is more preferable that it is 15-100 nm, and it is especially preferable that it is 20-80 nm. The average particle diameter can be measured by applying titanium black to a suitable substrate and observing with a scanning electron microscope. The specific surface area of the titanium black is not particularly limited. However, since the water repellency after the surface treatment of the titanium black with a water repellent agent has a predetermined performance, the value measured by the BET method is about 5 to 150 m @ 2. / G, more preferably about 20 to 100 m <2> / g.

(B) Carbon black In the present invention, titanium black and carbon black may be used in combination in addition to the use of titanium black alone as the black colorant. Carbon black is black fine particles including fine particles of carbon, and preferred particles are fine particles of carbon having a diameter of about 3 to 1,000 nm. Further, the surface of the fine particles can have functional groups containing various carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, nitrogen atoms, halogens, inorganic atoms and the like. Carbon black can be changed in its properties by variously changing the particle diameter (particle size), structure (particle connection), and surface properties (functional group) according to the intended application. It is also possible to change the blackness and affinity with the resin, or to provide conductivity.

  Specific examples of the carbon black include, for example, carbon blacks # 2400, # 2350, # 2300, # 2200, # 1000, # 980, # 970, # 960, # 950, # 900, # 850 manufactured by Mitsubishi Chemical Corporation. , MCF88, # 650, MA600, MA7, MA8, MA11, MA100, MA220, IL30B, IL31B, IL7B, IL11B, IL52B, # 4000, # 4010, # 55, # 52, # 50, # 47, # 45, # 44, # 40, # 33, # 32, # 30, # 20, # 10, # 5, CF9, # 3050, # 3150, # 3250, # 3750, # 3950, Diamond Black A, Diamond Black N220M, Diamond Black N234, Diamond Black I, Diamond Black LI, Diamond Black II, Diab N339, diamond black SH, diamond black SHA, diamond black LH, diamond black H, diamond black HA, diamond black SF, diamond black N550M, diamond black E, diamond black G, diamond black R, diamond black N760M, diamond Black LP. Carbon black thermax N990, N991, N907, N908, N990, N991, N908 made by Cancarb. Carbon black Asahi # 80, Asahi # 70, Asahi # 70L, Asahi F-200, Asahi # 66, Asahi # 66HN, Asahi # 60H, Asahi # 60U, Asahi # 60, Asahi # 55, Asahi # 50H, Asahi # 51, Asahi # 50U, Asahi # 50, Asahi # 35, Asahi # 15, Asahi Thermal, Degussa's carbon black ColorBlack Fw200, ColorBlack Fw2, ColorBlack Fw2, ColorBlack Fw1, ColorBlack 170, BlackBlack, BlackBlack S160, SpecialBlack6, SpecialBlack5, SpecialBlack4, SpecialBlack4A, PrintexU, PrintexV, Printex140U, Printex140V, etc. It can be mentioned.

The carbon black may preferably have an insulating property.
The carbon black having an insulating property is a carbon black exhibiting an insulating property when the volume resistance as a powder is measured by the following method. This insulating property is based on the fact that an organic compound is present on the surface of the carbon black particle, for example, an organic substance is adsorbed, coated or chemically bonded (grafted) on the surface of the carbon black particle. That is, carbon black is dispersed in propylene glycol monomethyl ether so that the molar ratio of benzyl methacrylate and methacrylic acid is a 70:30 copolymer (weight average molecular weight 30,000) and 20:80 weight ratio. Was applied to a chrome substrate having a thickness of 1.1 mm and 10 cm × 10 cm to prepare a coating film having a dry film thickness of 3 μm, and the coating film was further heated in a hot plate at 220 ° C. for about 5 minutes. Later, a volume resistivity value is measured in an environment of 23 ° C. and a relative humidity of 65% by applying with a high resistivity meter manufactured by Mitsubishi Chemical Corporation, conforming to JISK6911, and Hirestar UP (MCP-HT450). Carbon black having a volume resistance value of 10 5 Ω · cm or more, more preferably 10 6 Ω · cm or more, and particularly preferably 10 7 Ω · cm or more is preferred.

  As the carbon black as described above, for example, JP-A-11-60988, JP-A-11-60989, JP-A-10-330634, JP-A-11-80583, JP-A-11-80584, Resin-coated carbon black disclosed in JP-A-9-124969 and JP-A-9-95625 can be used.

  The average particle size (average primary particle size) of the black colorant used in combination with titanium black is preferably small from the viewpoint of foreign matter generation and the influence on the yield in the production of a solid-state imaging device. . The average primary particle size is preferably 50 to 100 nm, more preferably 50 nm or less, and preferably 30 nm or less. The average particle diameter can be measured by applying a black color material to a suitable substrate and observing with a scanning electron microscope.

  The content of titanium black in the thermosetting resin composition is not particularly limited, but the average transmittance in the visible region to infrared region (400 to 1,600 nm) of the formed light-shielding filter is 1. % Or less is preferable. It is preferable that an optical density of 2.0 or more is obtained with substantially the same film thickness as a color separation filter such as RGB. The amount of titanium black in the solid content of the photosensitive resin composition is preferably 10 to 95% by weight, and more preferably 20 to 80% by weight.

  In the present invention, as a black colorant, in addition to titanium black and carbon black, a black colorant other than titanium black and carbon black may be used in combination.

  As the black colorant that can be used in combination, various known black pigments and black dyes can be used, and iron oxide, manganese oxide, graphite and the like are particularly preferable from the viewpoint of realizing a high optical density with a small amount.

  As the other composition, the compound used in the above-described coloring composition can be applied.

[Preparation of colored thermosetting composition]
Three types of colored thermosetting compositions as shown in Table 1 were prepared. All were adjusted with the mass%.
(Colored thermosetting composition 1)
Colorant) Titanium black, solid content ratio: 58.8% by mass
Solid content) 20.0% by mass
Curing component) 12.0% by mass
(Colored thermosetting composition 2)
Colorant) Titanium black and carbon black, mixing ratio = 6: 5
Ratio in solid content: 66.0% by mass
Solid content) 20.0% by mass
Curing component) 12.0%
(Colored thermosetting composition 3)
Colorant) Carbon black, solid content ratio: 62.5% by mass
Solid content) 20.0% by mass
Curing component) 12.0%

[Example 1]
The color filter manufacturing process of the present invention is applied, and a color filter is formed through the following processes.

(A) A silicon oxide layer is formed as an etching stopper layer on the support with a film thickness of 70 nm (etching stopper layer forming step), and the colored thermosetting composition 1 is applied onto the silicon oxide layer by a spin coating method. Then, it is dried on a hot plate to form a black colored layer having a thickness of 400 nm (black light shielding layer forming step).
(B) Next, an i-line photoresist (Fhi622BC; manufactured by FUJIFILM Electronics Materials) is formed on the black colored layer with a film thickness of 800 nm.
(C) Subsequently, using an i-line stepper FPA-3000 (manufactured by Canon Inc.), exposure and development are performed to form a checkered pattern in which the arrays adjacent to the photoresist are shifted by the pixel pitch (patterning step) ).
(D) Next, an etching process including first to third dry etching processes is performed using the photoresist as an etching mask to form openings having a vertical and horizontal width of 0.9 μm arranged in a checkered pattern in the black colored layer. . The etching conditions described in Table 2 below are used. Note that the first etching process forms a rectangular opening in the black light-shielding layer, the second etching process removes residues attached to the opening, and the third etching process includes a silicon oxide layer (etching). Remove the stopper layer.

(E) Next, an i-line photoresist is formed on the black colored layer and so as to fill the opening.
(F) Then, exposure and development are performed using an i-line stepper to form a new checkered array of openings shifted by a pixel pitch with respect to the checkered pattern of openings formed in (d). A pattern is formed so as to leave a portion aligned with the boundary (patterning step).
(G) Next, an etching process including first to third dry etching processes is performed using the photoresist as an etching mask, and the black colored layer remaining in this etching process has a line width of 0.1 μm and a black matrix (light-shielding wall). Form. The etching conditions are the same as (d) above.
(H) Using a photolithography method, a colored layer is formed so as to fill the opening, and a color filter having a black matrix with a pixel pitch of 1.0 μm and a line width of 0.1 μm is formed.

[Comparative Example 1]
A conventional color filter manufacturing method and a manufacturing process using a KrF line exposure stepper are applied, and through the following steps, a conventional color filter, that is, a color having the same layer as the colored layer and a black matrix at the boundary between the colored layers Form a filter.
(A) A silicon oxide layer (etching stopper layer) is formed with a thickness of 70 nm on the support, and the colored thermosetting composition 1 is applied and heated on the silicon oxide layer to form a black colored layer with a thickness of 400 nm. Form with.
(B) A KrF photoresist is formed with a film thickness of 800 nm on the black colored layer.
(C) Next, exposure and development are performed with a KrF exposure stepper to form a matrix pattern having a line width of 0.1 μm.
(D) Using a KrF photoresist as a mask, an opening is formed in the black colored layer using a dry etching method to form a black matrix having a line width of 0.1 μm. The conditions for the etching process are the same as those in Table 2 used in Example 1 above.
(E) Next, RGB color filters are laminated using a photolithographic method to form an RGB color filter having a black matrix between colored layers.

  Evaluation of the color filter manufactured under the above conditions is as shown in Table 3 below. Evaluation items were productivity, miniaturization, and dimensional accuracy. As an evaluation method, the production cost is calculated as a cost newly added to the conventional manufacturing process (equipment cost, material) and compared with the conventional cost, and the evaluation standard is 10% from the conventional cost. In the case of the following increase, it exceeded (circle) and exceeded 10%, it was set as (triangle | delta) if it was an increase of 30% or less, and it was set as x in the case of the increase exceeding 30%. The miniaturization was evaluated by measuring the line width of the matrix pattern with an electron microscope. Evaluation criteria are ○ if the line width is 0.2 μm or less, exceeding 0.2 μm, Δ if 0.5 μm, and × if exceeding 0.5 μm. The dimensional accuracy was evaluated by laterally measuring the uniformity of the black matrix line width of four sides in the vertical and horizontal directions surrounding the periphery of one pixel with an electron microscope. The evaluation criteria are ○ if any of the four sides is 0.025 μm or less with respect to the desired line width (0.1 μm), Δ if the difference exceeds 0.025 μm and 0.05 μm or less. Was over 0.05 μm. In addition, the overall evaluation was as follows: ○: Good, Δ: Adoptable, × Not applicable.

  About the black light shielding layer (black matrix) of the color filter manufactured on the above conditions, as shown in the said Table 3, about Example 1, since evaluation is favorable or usable in all items, comprehensive evaluation is also carried out. It is good. Therefore, in Example 1, the demand for cost reduction is satisfied while the black matrix is formed by highly accurate rectangularity and fine processing. On the other hand, in the comparative example 1, although the requirements for miniaturization and dimensional accuracy are satisfied, the productivity is deteriorated and the cost is increased.

It is principal part sectional drawing of a solid-state imaging device. It is a top view which shows the arrangement | sequence of a color filter and a black matrix. It is process drawing explaining a color filter manufacturing process. It is sectional drawing which shows the state in which the black light shielding layer and the photoresist layer were formed. It is sectional drawing which shows the state which performed the 1st patterning process to the black light shielding layer. It is a top view which shows the state which patterned the black light shielding layer. It is the schematic of a dry etching apparatus. It is explanatory drawing which shows the state which performed the 1st etching process to the black light shielding layer. It is process drawing explaining each process performed at an etching process. It is a top view which shows the state which performed the 1st etching process to the black light shielding layer. It is sectional drawing which shows the state from which the photoresist was removed after the 1st etching process. It is sectional drawing which shows the state in which the photoresist layer was formed on the black light shielding layer and in the opening part. It is sectional drawing which shows the state which performed the 2nd patterning process to the black light shielding layer. It is a top view which shows the state which performed the 2nd patterning process to the black light shielding layer. It is explanatory drawing which shows the state which performed the 2nd etching process to the black light shielding layer. It is a top view which shows the state which performed the 2nd etching process to the black light shielding layer. It is sectional drawing which shows the state from which the photoresist was removed after the 2nd etching process. It is explanatory drawing which shows the state in which the 1st colored layer was formed. It is explanatory drawing which shows the state in which the planarization process was performed after forming the 1st colored layer. It is sectional drawing which shows the state in which the photoresist layer was formed on the black light shielding layer and the 1st colored layer. It is explanatory drawing which shows the state which performed the patterning process of the area | region which is going to form a 2nd colored layer in a photoresist layer. It is explanatory drawing which shows a state when the etching process of the area | region which forms a 2nd colored layer is performed. It is sectional drawing which shows the state in which the 2nd colored layer was formed. It is sectional drawing which shows the state in which the planarization process was performed after forming the 2nd colored layer. It is explanatory drawing which shows the state in which the planarization process was performed after forming the 3rd colored layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solid-state imaging device 13B B color filter 13G G color filter 13R R color filter 14 Black matrix 44 Support body 46 Black light shielding layer 47 1st photoresist layer 50 1st opening 65 2nd photoresist layer 67 Second opening

Claims (4)

A color filter in which a colored layer of at least two colors is arranged on a support, and a black light-shielding layer made of a composition in which a black colorant is dispersed is arranged at a position aligned with the boundary of the colored layer. A manufacturing method comprising:
And black light shielding layer forming step of forming the black shielding light layer on a support,
By dry etching, a first opening forming an etching step for forming a first opening checkered pattern of the array to each other by shifting a predetermined pitch adjacent to the black shield light layer,
Wherein at a predetermined pitch shift sequences, the second opening checkerboard pattern which is located in the middle of adjacent said first opening is formed on the black shield light layer with respect to the first opening And a second opening forming etching step of forming a black matrix leaving a portion matched with the boundary of the colored layer. A color filter in which a colored layer of at least two colors is arranged on a support, and a black light-shielding layer made of a composition in which a black colorant is dispersed is arranged at a position aligned with the boundary of the colored layer. A manufacturing method comprising:
A black light shielding layer forming step of forming a black light shielding layer comprising a composition in which a black colorant is dispersed on the support layer;
A first patterning step of forming a first photoresist layer on the black light-shielding layer to form a checkered first pattern in which adjacent arrays are shifted by a predetermined pitch;
A first opening formation etching step of forming a checkered first opening by using the first photoresist layer as a mask by dry etching;
Forming a second photoresist layer so as to fill the black shielding light layer and the first opening, in sequence shifted the predetermined pitch with respect to the first opening, adjacent the first A second patterning step of forming a checkered second pattern located in the middle of the opening of
By performing a dry etching process, a second opening having a checkered pattern at a position shifted by the predetermined pitch with respect to the first opening is formed using the second photoresist layer as a mask, and a boundary between the colored layers is formed. And a second opening forming etching step of forming a black matrix while leaving a portion matched to the above.   The method for producing a color filter according to claim 1, wherein the black colorant is titanium black. The dry etching process according to claim 1 to 3 the method for producing a color filter according to any one, characterized by using a mixed gas containing at least fluorocarbon gas and oxygen gas.

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