JP2006128433A - Optical device equipped with optical filter, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device equipped with an optical filter which is formed on the light-incident side or light-exiting side of a photoelectric converter or a light modulation portion, has no deterioration of shape even if a unit cell is miniaturized, will not have degradation produced in the spectral characteristics due to deterioration of the shape, and can be manufactured with a high productivity and high yield. <P>SOLUTION: In a CCD solid-state imaging device 20, a photosensor 3 and a signal charge vertical transfer 4 are formed in a silicon substrate 1, and then a first gate electrode 6, etc. are formed thereon via a gate insulation film 2, thus forming the photoelectric converter. On the light-incident side of the photoelectric converter, partitions 13 are so formed as to rise vertically to the substrate 1 to mutually divide a color filter layer 15, in correspondence with individual unit cell regions. In a light-receiving region 14 surrounded by the partitions 13, a pixel color filter layer 15 is formed by the reflow of a dye-containing photoresist, or by using a dye-containing negative type chemically-amplified photoresist. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical device with an optical filter provided with an optical filter on a light incident side or a light outgoing side of a photoelectric conversion unit or a light modulation unit, such as a CCD (Charge Coupled Device) or a liquid crystal display device, and a method for manufacturing the same. It is.

  In a single-plate color solid-state imaging device, a multicolor color filter in which a plurality of color pixel color filters having different transmission wavelength characteristics (spectral characteristics) are arranged in a predetermined repeating color arrangement is provided on the light incident side of the sensor unit. The desired color signal is obtained.

  In recent years, solid-state imaging devices represented by CCDs have achieved significant improvements in the increase in the number of pixels and the downsizing of the apparatus, and accordingly, the color reproducibility and color unevenness are also improved with regard to the structure of the multicolor filter. Various devices have been devised for the purpose of preventing this.

  For example, a multicolor filter for a solid-state image sensor has been conventionally formed by a staining method in which a chromosome such as casein or gelatin is colored with a dye corresponding to the color of the color filter. With the miniaturization of unit cells (unit pixels) of an image sensor, it has become difficult to form a fine color filter with sufficient accuracy by a staining method.

  Therefore, in place of the dyeing method, a method using a dye-containing photoresist having excellent processability has been adopted. Here, the dye-containing photoresist is a photoresist formed by mixing a dye with a photoresist composed of a binder resin such as a novolak resin, a photosensitive agent, and a thermosetting agent.

  For example, Patent Document 1 described below discloses a method for forming a multicolor filter including four color filters, a white filter, a yellow filter, a cyan filter, and a green filter. In this method, the spectral characteristic required for the white filter is obtained by increasing the transmittance of the yellow filter, and the white filter is formed by reducing the thickness of the yellow filter. The yellow filter and the white filter are formed simultaneously in a process using a yellow dye.

  FIG. 11 is a cross-sectional view showing a method for forming the conventional multicolor filter 109 disclosed in Patent Document 1. In FIG.

  First, as shown in FIG. 11A, a yellow dye-containing positive photoresist 102 is applied to a thickness of 1.5 μm on a base layer 101 having a planarized surface. A photo sensor unit (not shown) is provided below the base layer 101. In the case of a CCD solid-state imaging device, a transfer electrode, a light shielding film, a CCD register, and the like are further formed.

  Next, as shown in FIG. 11 (b), the yellow mask and the white filter are covered with a first mask 103, and the yellow dye-containing positive photoresist 102 is exposed for the first time. Do.

  Next, as shown in FIG. 11C, the portion other than the portion where the white filter is formed is covered with the second mask 103, and the yellow dye-containing positive is obtained with an exposure amount of about 80% of the first exposure amount. A second exposure is performed on the mold photoresist 102.

  Next, as shown in FIG. 11D, batch development and thermosetting are performed to remove the exposed portion. As a result, a yellow filter 105 made of a yellow dye-containing positive photoresist 102 is formed in the non-exposed area, and a yellow dye-containing positive photoresist 102 is made in the area where the second incomplete exposure has been performed. A white filter 106 having a thickness of about 20% of the filter 105 is formed.

  Subsequently, using a cyan dye-containing positive photoresist, the steps of resist application, pattern exposure, development, and thermosetting are performed in the same manner as described above to form the cyan filter 107. Further, the same process is performed using a green dye-containing positive photoresist to form a green filter 108.

  As described above, the color filters for each color are sequentially formed, and as shown in FIG. 11E, a yellow filter 105, a white filter 106, a cyan filter 107, and a green filter 108 are arranged in a predetermined color arrangement. A color filter 109 is formed.

  As described above, the dye-containing photoresist is formed by mixing a dye for imparting color filter characteristics to a photoresist composed of a binder resin, a photosensitive agent, and a thermosetting agent. Ordinary general photoresists do not contain such dyes except in special cases (however, there are those that add exposure light absorbing dyes for the purpose of preventing reflection of exposure light).

  Specifically, the dye-containing photoresist contains about 10% or more of the dye in the solid content. Dyes are used to achieve the spectral characteristics of solid-state image sensors, but are dyes that do not function as photoresists. If the ratio of the dyes in the photoresist component is too high, it is compared to photoresists that do not contain dyes. As a result, the resist function deteriorates. Therefore, it is necessary to ensure compatibility with the resist function while ensuring good spectral characteristics of the color filter. Also, exposure and development processing by a known photolithography method may impair the color filter and the resist function. For example, the light used for exposure (g-line, i-line, excimer laser light, etc.) is absorbed by the added dye, or the resist shape or This is the case when the color filter characteristics are affected. In these cases, when patterning is performed by exposure and development processing in photolithography, it may be difficult to form the side surface of the color filter in a shape that is nearly perpendicular to the base.

  FIG. 12 is a schematic cross-sectional view of a CCD solid-state imaging device 110 for explaining the problems of the conventional color filter forming method disclosed in Patent Document 1 and the like. In the CCD solid-state imaging device 110, a photosensor portion 113 is formed at the center of each unit cell region of the silicon substrate 111, and a first gate electrode 114 constituting a signal charge vertical transfer portion is formed at the upper side of the photosensor portion 113. For example, a green pixel color filter 116 a, a blue pixel color filter 116 b, a red pixel color filter 116 c, and a microlens 117 are provided above them via a planarization film 115.

  As shown in FIG. 12, in the CCD solid-state imaging device 110, there is no means for forming or partitioning the color filters 116a to 116c, so that a color filter having a rectangular shape or a cross-sectional shape close to the rectangular shape is formed. Can not do it. For example, when the cross-sectional shape of the color filter is trapezoidal or inverted trapezoidal, the thickness of the color filter is not uniform, and the boundary between the color filters becomes ambiguous. Due to the deterioration of the shape of the color filter, the spectral characteristics of the color filters 116a to 116c are deteriorated, and color mixture occurs due to the overlapping of adjacent color filters. This is a particularly serious problem as the unit pixel of the solid-state image sensor is miniaturized to 2.5 μm or less.

  FIG. 13 is a micrograph (a) showing an example of a cross-sectional shape of a conventional color filter, and a graph (b) showing an example of spectral characteristics. As shown in FIG. 13 (a), the cross-sectional shape of the color filter is a trapezoid that is relatively close to a rectangle when the length L of one side is 2.5 μm. When L is 2.2 μm, the flatness of the upper surface is lost and the shape is not even a trapezoid. Correspondingly, in the graph showing the wavelength dependence of the transmittance in FIG. 13B, the color filter with L of 2.2 μm is indicated by the double-pointed arrow as compared with the color filter with L of 2.5 μm. The wavelength width of the transmission region is widened, and as indicated by a one-way arrow, the transmittance in the left and right wavelength regions, which is the original absorption region, is insufficiently reduced, and color purity and color separation related to color reproducibility It can be seen that the spectral characteristics such as performance are deteriorated.

  On the other hand, with the downsizing of the solid-state imaging device and the increase in density of the unit pixels, there is a problem that the light receiving area of the unit pixel is reduced and the sensitivity of the solid-state imaging device is lowered. As a countermeasure, in recent solid-state imaging devices, a configuration is used in which a microlens is provided for each unit pixel on the light incident side of a color filter, and incident light is condensed on a photosensor unit. At this time, since the microlens formation process is strongly dependent on the base of the lens shape, if the upper shape of the color filter is not flat, the variation of the microlens shape becomes large and it is difficult to ensure uniform sensitivity. There is a problem.

  Therefore, in Patent Document 2 to be described later, a metal thin film is provided in a lattice shape above the metal light-shielding film of the photosensor portion of the solid-state imaging device, and unit cell (unit pixel) regions are partitioned in a bowl shape, and partitioned by this metal thin film. A solid-state imaging device has been proposed that realizes high sensitivity by forming a color filter and a microlens for each unit cell region, and reduces sensitivity variations and image variations.

  FIG. 14 is a cross-sectional view showing the structure of the CCD solid-state imaging device 120 disclosed in Patent Document 2. As shown in FIG.

  In the CCD solid-state imaging device 120, a gate insulating film 122 is formed on the upper surface of a silicon substrate 121, and a photosensor portion 123 made of a pn junction (not shown) is provided in the central portion of FIG. The n-type region of the vertical transfer unit (not shown) is formed on the side of the photosensor unit 123.

  On the gate insulating film 122, the first gate electrode 124 is formed by patterning above the n-type region of the vertical transfer portion, and the surface of the first gate electrode 124 is covered with the insulating film 125. A reflow film 126 such as PSG (phosphorus glass) is formed on the photosensor portion 123 and the first gate electrode 124. An upper region of the photosensor portion 123 is opened on the reflow film 126, and the first gate electrode 124 is formed. A light shielding metal film 127 (photoshield) is formed so as to cover it, and a passivation film 128 such as a silicon nitride film by a plasma CVD method (Chemical Vapor Deposition) is further formed on the entire surface.

  On the light shielding metal film 127, a metal thin film 131 is formed in a lattice shape so as to rise perpendicularly to the silicon substrate 121. The metal thin film 131 surrounds the unit cell region centering on the photosensor unit 123 in a bowl shape, and the inside thereof becomes a light receiving region divided into segments. A color filter layer 132 is formed in the light receiving portion region, and a microlens 133 is formed thereon. Thus, the color filter layer 132 and the microlens 133 are disposed independently for each partitioned light receiving area.

  A method for manufacturing the CCD solid-state imaging device 120 will be described below according to Patent Document 2.

  First, after forming a desired impurity diffusion layer on the silicon substrate 121 by ion implantation or the like, the gate insulating film 122 is formed by thermal oxidation or CVD. Next, the first gate electrode 124 is deposited by a CVD method and patterned into a predetermined shape by photolithography and dry etching. Next, after the first gate electrode 124 is covered with an insulating film by an oxidation method or a CVD method, the second gate electrode 5 (not shown) is formed and processed. This is repeated in the case of an electrode structure having three or more layers. Next, an insulating film 125 is formed on these electrode structures by an oxidation method or a CVD method.

  Next, a reflow film 126 such as PSG is formed on the gate insulating film 122 and the first gate electrode 124 above the photosensor unit 123, and a region above the photosensor unit 123 is opened on the first reflow film 126. A light shielding metal film 127 (photoshield) is formed so as to cover one gate electrode 124, and a passivation film 128 such as a silicon nitride film formed by plasma CVD is laminated on the entire surface. As the passivation film 128, it is desirable to select a film that can serve as a stopper with respect to a silicon oxide film removal etchant (for example, a hydrogen fluoride chemical solution) that is formed as a planarizing film in the next step.

  Next, a resin film by a coating method such as SOG (spin-on-glass), a silicon oxide film or BPSG (boron phosphorus glass) film by a CVD method using TEOS (tetraethoxysilane), or an oxidation by a bias high-density plasma CVD method A planarizing film is formed by a silicon-based film or the like, and the surface is planarized by etch back, CMP (Chemical Mechanical Polishing), or the like.

  Next, a lattice-like groove having a width of 1 μm or less is formed by photolithography and dry etching at the boundary between the unit pixel regions of the planarizing film. Thereafter, using a high aspect ratio embedding improvement technique such as high-pressure reflow, the metal thin film 131 is embedded in the groove portion by CVD or sputtering, and then the metal thin film on the planarizing film is removed by etch back or CMP. Only the metal thin film 131 embedded in the groove is left. The material of the metal thin film 131 is optimally high reflectivity aluminum or the like.

  Next, the planarizing film made of a silicon oxide film or the like is selectively removed using an etchant such as a hydrogen fluoride chemical solution, and the light receiving portion region surrounded by the metal thin film 131 is exposed.

  Next, a multicolor filter in which a plurality of pixel color filter layers 132 are arranged in a predetermined repeated color array is formed. At this time, first, a pixel color filter layer 132 of one of a plurality of colors is formed in the light receiving region of all the unit pixels by a dyeing method or application of a dye-containing photoresist, followed by photolithography and etching. Patterning is performed with the metal thin film 131 as a boundary, leaving only the pixel color filter layer 132 at a predetermined pixel position determined by a predetermined repeated color arrangement. This process is repeated for the number of colors of a plurality of colors to form a multicolor color filter in which the pixel color filter layers 132 of a plurality of colors are arranged in a predetermined repeated color arrangement.

  Finally, a microlens 133 is formed on each pixel color filter layer 132 using a hot-melt transparent resin or the like.

  According to the CCD solid-state imaging device 120 described above, the pixel color filter layer 132 is partitioned for each unit cell with the metal thin film 131 as a boundary, and the light that has reached the metal thin film 131 is reflected among the light incident on the light receiving portion region. Then, since the light is guided toward the center of the photo sensor unit 123, the light collection efficiency is improved, and the imaging sensitivity is improved. Further, since there is no light transmitted to the adjacent unit cell, the mixed color component is eliminated and the color unevenness is reduced.

  Further, the pixel color filter 132 is formed so as to be in close contact with the metal thin film 131 and is formed along the inner wall surface of the metal thin film 131, so that the shape deterioration of the pixel color filter layer 132 is prevented and the shape of the color filter is reduced. The problem of deterioration of spectral characteristics due to deterioration is also solved.

  Furthermore, since the microlens 133 is formed on the pixel color filter layer 132 partitioned by the metal thin film 131, the ground shape of the microlens 133 is stabilized, and as a result, the shape of the microlens 133 is also stabilized, Sensitivity variation from one to another is reduced.

JP 2001-144277 (3rd page, FIGS. 4 and 5) JP-A-10-163462 (2nd and 3rd pages, FIG. 1)

  In the method of Patent Document 2, a lithography process for patterning the pixel color filter layer 132 using the metal thin film 131 as a boundary is required regardless of whether the dyeing method or the dye-containing photoresist method is used. The position must be accurately aligned with the position of the metal thin film 131.

  When the mask is displaced, a gap is generated between the metal thin film 131 and the pixel color filter layer 132, and the shape of the pixel color filter layer 132 cannot be formed by the metal thin film 131. The problem of deterioration of spectral characteristics due to shape deterioration cannot be solved.

  Further, the light irradiated to the metal thin film 131 during exposure is reflected or scattered by the side wall of the metal thin film 131 and is incident on the dye-containing photoresist in the non-exposed region. There is also concern that the characteristics will deteriorate.

  As described above, in the method of Patent Document 2, a decrease in accuracy when the pixel color filter layer 132 is patterned by lithography directly leads to a decrease in performance of the solid-state imaging device and a decrease in manufacturing yield. However, as the number of pixels of the solid-state imaging device increases and the unit cell (unit pixel) becomes smaller, it becomes more difficult to accurately align the mask with respect to all unit cells.

  The present invention has been made in view of such a situation, and an object thereof is an optical device including an optical filter on a light incident side or a light emitting side of a photoelectric conversion unit or a light modulation unit, and a unit An object of the present invention is to provide an optical device including an optical filter that can be manufactured with good productivity and yield, and a method for manufacturing the optical device.

That is, the present invention is an optical device including an optical filter on a light incident side or a light emitting side of a photoelectric conversion unit or a light modulation unit, and the optical filter includes:
A partition that separates the filter units corresponding to the unit cell regions on the light incident side or the light emitting side of the photoelectric conversion unit or the light modulation unit;
And a filter unit that is arranged in a region surrounded by the partition and is made of a filter material that is in close contact with the partition by reflow, and a photoelectric conversion unit. Alternatively, an optical device including an optical filter on a light incident side or a light emitting side of the light modulation unit, wherein the optical filter includes:
A partition that separates the filter units corresponding to the unit cell regions on the light incident side or the light emitting side of the photoelectric conversion unit or the light modulation unit;
A second optical filter-equipped optical filter, comprising: a filter portion made of a negative-type chemically amplified photoresist that is disposed in a region surrounded by the compartments and is adhered and cured to the compartments by a chemical amplification action. It relates to the device.

Moreover, it is a manufacturing method of the first optical device with an optical filter,
Forming a partition that separates the unit cell regions on the light incident side or light emission side of the photoelectric conversion unit or light modulation unit;
Providing the filter material in a region surrounded by the partition;
A method of manufacturing the first optical device with an optical filter, comprising the step of reflowing the filter material by heating to a predetermined temperature, and the manufacturing method of the second optical device with an optical filter,
Forming a partition that separates the unit cell regions on the light incident side or light emission side of the photoelectric conversion unit or light modulation unit;
Providing a negative chemically amplified dye-containing photoresist on the entire surface of at least the light receiving region surrounded by the partition;
Exposing the chemically amplified photoresist present inside the compartment; and
Manufacturing an optical device with a second optical filter, comprising: a step of insolubilizing the unexposed chemically amplified photoresist present between the exposed chemically amplified photoresist and the partition by heat treatment. It is related to the method.

  In the first optical device with an optical filter of the present invention, in the filter portion corresponding to the unit cell region, the filter material is in close contact with the partition body that separates the filter portions from each other by reflow. In the second optical device with an optical filter according to the present invention, in the filter unit corresponding to the unit cell region, the negative chemically amplified photoresist is chemically amplified with respect to the partition body that separates the filter unit from each other. It is closely cured by action. In any case, since the filter part is formed in a shape along the inner wall surface of the partition body, for example, rectangular or substantially rectangular, inconveniences such as spectral characteristic deterioration due to deterioration of the shape of the filter part are prevented. The

  Moreover, the manufacturing method of the 1st optical apparatus with an optical filter of this invention has the process of providing the said filter material in the area | region enclosed by the said division body, and the process of heating the said filter material to predetermined temperature, and making it reflow Have. In this manufacturing method, the reflowed filter material is in close contact with the partition body in a fluid state, and is solidified in this close contact state to form the filter section. Therefore, the filter section molds the partition body. Thus, it is automatically formed into a shape along the inner wall. Therefore, it is not necessary to pattern the filter material accurately in the step of providing the filter material in the region surrounded by the compartments.

  The second method for manufacturing an optical device with an optical filter according to the present invention includes a step of providing a negative type chemically amplified dye-containing photoresist on the entire surface of the light receiving part region surrounded by at least the partition, and the partition The step of exposing the chemically amplified photoresist existing inside and the unexposed chemical amplification present between the exposed chemically amplified photoresist and the partition by a heat treatment after exposure. A step of insolubilizing the mold photoresist. In this manufacturing method, the unexposed chemically amplified photoresist is in close contact with the compartment in a fluid state, and the entire chemically amplified dye-containing photoresist surrounded by the compartment is in close contact. Since the filter portion is formed by insolubilization, the filter portion is automatically formed into a shape along the inner wall of the partition body as a mold. In this case, the negative chemically amplified dye-containing photoresist is used as a filter material, and the unexposed chemically amplified photoresist existing between the exposed chemically amplified photoresist and the partition is exposed. Since there is a step of insolubilization by a subsequent heat treatment, in the step of exposing the chemically amplified photoresist, it is not necessary to expose the chemically amplified photoresist in accordance with the position and shape of the compartments.

  As described above, the manufacturing method of the first and second optical devices with an optical filter does not require a step of accurately patterning the filter portion in accordance with the partition by photolithography. Even if the size is reduced, the shape of the filter portion is hardly deteriorated. Further, the optical filter can be formed in a process that does not require much exposure accuracy. As a result, the first and second optical devices with the optical filter can be manufactured with high productivity, good manufacturing yield, and low cost. Can be manufactured.

  In the first optical device with an optical filter and the manufacturing method thereof according to the present invention, it is preferable that the partition body is made of a material that is not deformed by the reflow.

  The filter material is not particularly limited, but a dye-containing photoresist is preferably used because it can be arranged by patterning by lithography and etching. Alternatively, a material that can be arranged by a printing method is used as the filter material, and the filter material may be arranged by a printing method such as an inkjet method.

  In addition, after applying the dye-containing photoresist, it is preferable to pattern the filter material so that the outer surface is present at a position away from the inner wall surface of the partition when being patterned by lithography and etching. . In this way, the filter material can be patterned with a sufficient margin against misalignment, and adversely affected by patterning the adjacent unit cell region by mistake or scattering of irradiation light on the adjacent unit cell region. You can avoid giving.

  In the second method for producing an optical device with an optical filter according to the present invention, the unexposed chemically amplified photoresist existing outside the predetermined unit cell region may be removed. This is a process that is necessary when the optical filter is composed of a plurality of types of filter units having different light transmission characteristics. In this case, first, one type of filter unit among a plurality of types is formed in a predetermined unit cell region determined by a predetermined repetitive arrangement, and this filter unit is not formed outside the predetermined unit cell region. This process is repeated for a plurality of types to form the optical filter in which a plurality of types of filter units are arranged in a predetermined repeating arrangement.

  The chemically amplified photoresist may be exposed except for a contact region with the inner wall surface of the partition. In this way, the filter material can be patterned with a sufficient margin against misalignment in the same manner as described above for the first method for manufacturing an optical device with an optical filter of the present invention. It is possible to avoid patterning with the region as a boundary or adversely affecting the adjacent unit cell region due to scattering of irradiation light.

  In the present invention, the optical filter may be constituted by a plurality of types of the filter units having different light transmission characteristics. The optical filter may be configured as a multicolor color filter having different transmission wavelength characteristics. The optical filter may be a single color shading filter or a multicolored color filter.

  Moreover, it is good for the said division body to be formed as a wall part of a frame-shaped pattern. The shape of the partition is not particularly limited, but a shape that is easy to form is preferable.

  Further, it is preferable that the partition body is made of a material having a refractive index smaller than that of the filter material. For example, the partition body may be made of porous silica. In this way, a structure is formed in which the filter portion having a high refractive index is surrounded by the partition having a low refractive index. This is because the core having a high refractive index in the optical waveguide becomes a cladding having a low refractive index. The structure is similar to what is surrounded. As a result, light that is about to leak out from the filter portion having a high refractive index is incident on the partition body having a low refractive index, is easily reflected and returned to the filter portion, and light leaks out. It can be suppressed. In this way, when the optical device of the present invention is a light receiving device, the light reaching the partition body out of the light incident on the light receiving portion region of the unit cell is reflected to be a photosensor in the central portion. Therefore, the light collection efficiency is improved and the imaging sensitivity is improved. Furthermore, since the light transmitted to the adjacent unit cells is reduced, the color mixture component is reduced and the color unevenness is reduced. In addition, when the optical device of the present invention is a light emitting device, the light reaching the partition is reflected among the light emitted from the light emitting unit and guided to the light emitting side, so that the light emission efficiency is improved. And the brightness is improved.

  Moreover, it is preferable that a light reflecting layer is provided on a side surface of the partition. In this case, when the optical device of the present invention is a light receiving device, the light reaching the partition is reflected among the light incident on the light receiving portion region of the unit cell, and the photosensor portion at the center portion Therefore, the light collection efficiency is improved and the imaging sensitivity is improved. Furthermore, the spectral color characteristics are improved, for example, by eliminating the light transmitted to the adjacent unit cells, the mixed color component is eliminated and the color unevenness is reduced. In addition, when the optical device of the present invention is a light emitting device, the light reaching the partition is reflected among the light emitted from the light emitting unit and guided to the light emitting side, so that the light emission efficiency is improved. And the brightness is improved.

  Further, in the unit cell region, a high refractive index material layer is disposed in a light transmission region between the photoelectric conversion unit or the light modulation unit as a base of the optical filter, and a low refractive index material layer is provided around the high refractive index material layer. A refractive index material layer is preferably disposed. At this time, for example, the high refractive index material layer may be made of silicon nitride, and the low refractive index material layer may be made of porous silica. In this way, a structure similar to the optical waveguide similar to that in the optical filter region described above can be realized also in the light transmission region in the base region of the optical filter. As a result, when the optical device of the present invention is a light receiving device, the light that has reached the partition body out of the light incident on the light receiving region of the unit cell is reflected and reflected by the photosensor portion at the center. Therefore, the light collection efficiency is improved and the imaging sensitivity is improved. Further, the light passing through the adjacent unit cells is reduced, so that the color mixing component is reduced and the color unevenness is reduced. In addition, when the optical device of the present invention is a light emitting device, the light reaching the partition is reflected among the light emitted from the light emitting unit and guided to the light emitting side, so that the light emission efficiency is improved. And the brightness is improved.

  Moreover, it is preferable that a stopper layer for etching the partition is formed between the base and the optical filter.

  Further, it is preferable that a micro lens is provided for each unit cell on the light incident side or the light emitting side of the filter unit. As a result, since the microlens is formed on the filter section partitioned by the partition body, the base shape of the microlens is stabilized, and as a result, the shape of the microlens is also stable, and there is a variation for each unit cell. Decrease.

  The optical device with an optical filter is preferably configured as a solid-state imaging device and manufactured. The present invention is most effectively applied to a solid-state imaging device such as a CCD or a MOS image sensor in which miniaturization and unit cell (unit pixel) density are most advanced. Further, the present invention may be applied to a liquid crystal display (LCD) which is a display device having the light modulation unit.

  Next, a preferred embodiment of the present invention will be described specifically and in detail with reference to the drawings.

Embodiment 1
The first embodiment mainly corresponds to claims 1 to 3 and 16 to 19. That is, the first embodiment relates to a CCD solid-state imaging device including the optical filter made of the dye-containing photoresist as an example of an optical device including the first optical filter of the present invention, and a method for manufacturing the same. The optical filter portion constituting the optical filter is formed by reflowing the dye-containing photoresist.

  The dye-containing photoresist to be reflowed contains, as a resist solid content, a dye, a resin, a thermosetting agent, a photosensitizer, and an additive (for example, a striation inhibitor such as a surfactant). Thus, a material in which these solid contents are dissolved in an organic solvent. The reflow temperature is preferably 130 ° C to 240 ° C. Further, a reflow auxiliary agent or the like is not particularly required, and the reflow is performed at a temperature equal to or higher than the thermal softening point of the resist film composed of the solid content described above.

  1 and 2 are explanatory views showing the structure of a CCD solid-state imaging device 20 based on the first embodiment. FIG. 2 is a top view of the CCD solid-state imaging device 20, and FIG. 1 is a cross-sectional view of the CCD solid-state imaging device 20 at the position indicated by the line AA in FIG.

  As shown in FIG. 1, in a CCD solid-state imaging device 20, a gate insulating film 2 is formed on the upper surface of a silicon substrate 1, and a photo of a pn junction shown in the center of FIG. A sensor unit 3 is formed, and an n-type region 4 of a vertical transfer unit that transfers signal charges in the vertical direction is formed on the side of the photosensor unit 3. An overflow drain region 5 is formed below the silicon substrate 1.

  On the gate insulating film 2, a first gate electrode (vertical transfer electrode) 6 is formed by patterning above the n-type region 4 of the vertical transfer portion, and the surface of the first gate electrode 6 is covered with an insulating film 8. Has been. Further, as shown in FIG. 2, the second gate electrode 7 is formed so as to partially overlap the first gate electrode 6, and the surface thereof is also covered with the insulating film 8. The first gate electrode 6 and the second gate electrode 7 are electrodes constituting the vertical transfer unit 9. When the vertical transfer unit 9 has an electrode structure having three or more layers, the same number of gate electrodes as those described above are provided.

  FIG. 3 is a more detailed cross-sectional view (a) of the silicon substrate 1 and a potential diagram (b) showing the flow of signal charges. The potential diagram shows the potential energy of electrons on the OA line in the horizontal direction and the OB line in the substrate depth direction shown in the cross-sectional view. The signal charges (electrons) accumulated in the photosensor unit 3 during light reception are extracted to the n-type region 4 of the vertical transfer unit by the read voltage applied to the first gate electrode 6, and thereafter shown in FIG. The vertical transfer unit 9 is transferred in the vertical direction, and further, the horizontal transfer unit (not shown) is transferred in the horizontal direction, and then output to an amplifier (not shown). In addition, when the signal charge accumulated in the photosensor unit 3 becomes excessive, the excess signal charge flows out to the overflow drain region.

  As shown in FIG. 1, on the gate electrode such as the first gate electrode 6, tungsten or the like is used so as to cover the gate electrode such as the first gate electrode 6 while opening a region above the photosensor portion 3. The light shielding film 10 is formed. A reflow film 11 made of BPSG (boron phosphorous glass) or the like is formed on the gate insulating film 2 and the light shielding film 10 above the photosensor unit 3, and is formed on the reflow film 11 by a plasma CVD method. The silicon nitride film 12 thus formed is formed to form the base of the pixel color filter layer 15.

  A partition 13 is formed in a lattice shape on the silicon nitride film 12 so as to rise vertically to the silicon substrate 1. The partition 13 surrounds a unit cell (unit pixel) region centered on the photosensor unit 3 in a bowl shape, and becomes a light receiving unit region 14 that is partitioned into segments. A pixel color filter layer 15 as the filter portion is formed in the light receiving portion region 14, and a microlens 17 corresponding to each unit cell is formed thereon via a planarizing film 16.

  As described above, the pixel color filter layer 15 is provided independently for each partitioned light receiving region 14. For example, a green color filter, a red color filter, a blue color filter, a yellow color filter, a cyan color filter, and a magenta color filter are formed in the pixel color filter layer 15 according to the selection of the dye to be mixed, and the pixel color filter layer 15 is arranged in a predetermined repeating color array. A multicolor color filter comprising an array of pixel color filter layers 15 is formed as the optical filter.

  4 to 6 are flowcharts showing a method for manufacturing the multicolor color filter and the microlens of the CCD solid-state imaging device based on the first embodiment. 4 to 6, the silicon substrate 1 is not shown, and only the position of the photosensor unit 3 is shown (the same applies hereinafter). FIG. 4A shows a state in which the silicon nitride film 12 is formed by a known method in the manufacturing process of the CCD solid-state imaging device 20. Hereinafter, a process of manufacturing a multicolor filter and a microlens is started from this state. Will be explained.

  First, the partition 13 is formed by the steps shown in FIGS.

  First, as shown in FIG. 4B, a partition material layer 21 to be formed into a lattice-shaped partition body 13 in a later step is formed. The material of the partition 13 may be any material as long as it does not cause substantial deformation or alteration at the heating temperature in the reflow process of the dye-containing filter material 27 performed in the subsequent process. It can be used regardless of whether or not.

  For example, if the partition 13 is formed of an organic film, an acrylic resin, a polystyrene resin, a polyimide resin, an organic SOG resin, or the like is applied on the silicon nitride film 12, and then thermosetting is performed. Form a film. In addition, if an inorganic film is used, a polycrystalline silicon film is formed by a CVD method, a silicon oxide film is formed by a plasma CVD method, a silicon nitride film is formed by a plasma CVD method, a sputtering method or A metal film such as tungsten or aluminum is formed by a CVD method. Subsequent steps will be described on the assumption that the partition 13 is formed using a polycrystalline silicon film formed by the CVD method.

  Next, as shown in FIG. 4C, a resist pattern 22 corresponding to the arrangement position of the partition 13 is formed by photolithography.

  Next, as shown in FIG. 4D, using the resist pattern 22 as a mask, the partition material layer 21 made of a polycrystalline silicon film is dry-etched to form a partition 13 patterned in a lattice shape. Thereby, the light receiving part region 14 surrounded by the partition 13 in a bowl shape is formed in each unit cell region.

  Subsequently, by the steps shown in FIGS. 5E to 6I, the pixel color filter layers 15 of a plurality of colors are formed in each light receiving region 14 with a predetermined repetitive color arrangement to form a multicolor filter. . In this case, first, the pixel color filter layer 15 of one color among the plurality of colors is formed in the light receiving part region 14 at a predetermined pixel position determined by a predetermined repeated color arrangement. This process is repeated for the number of colors of a plurality of colors to form a multicolor color filter in which the pixel color filter layers 15 of a plurality of colors are arranged in a predetermined repeated color arrangement.

  First, as shown in FIG. 5 (e), one of a plurality of colors, for example, a green dye-containing photoresist layer 23 is formed on the entire surface by a coating method or the like.

  Next, as shown in FIG. 5F, the mask 24 is used to expose the dye-containing photoresist layer 23 other than the unit cell 25 in which the green pixel color filter layer 15a is provided. At this time, the exposure is performed so that the exposure region 27 slightly enters the light receiving region of the unit cell 25 instead of performing exposure using the partition 13 as a boundary as in the method of Patent Document 2. That is, the exposure is performed so that the horizontal position of the outer peripheral portion of the mask 24 is inside the inner wall surface of the partition 13 in the unit cell 25. In this way, the dye-containing photoresist layer 23 can be patterned inside the partition 13 with a sufficient margin for misregistration, and it is possible to avoid erroneous patterning with the adjacent unit cell region as a boundary.

  Next, as shown in FIG. 5G, the dye-containing photoresist 23 in the exposed region 27 is removed by development processing. Next, in order to deactivate the light absorbing ability by decomposing the photosensitizer (quinonediazide compound) contained in the dye-containing photoresist layer 28 arranged in the light receiving part region of the unit cell 25 in this manner, Is used to perform exposure processing (bleaching exposure).

  Next, as shown in FIG. 5 (h), the dye-containing photoresist 28 is heated to a temperature higher than the softening point to be thermally reflowed and spread over the entire light receiving region. The dye-containing photoresist having fluidity is in close contact with the silicon nitride film 12 and the partition body 13 and solidifies in that state, thereby forming the partition body 13 as a mold and a shape along the inner wall surface, for example, a rectangular cross section. The green pixel color filter layer 15a is formed automatically in a rectangular parallelepiped shape.

  As described above, it is sufficient that the dye-containing photoresist 28 before reflow shown in FIG. 5G is in the region surrounded by the partitions 13 and does not need to be patterned accurately. Therefore, the dye-containing photoresist can be arranged by a printing method such as an ink jet method. Although the case where the photoresist is a positive type has been described here, it may be a negative type. In this case, the non-exposed region 26 and the exposed region 27 may be reversed in FIG. .

  Next, as shown in FIG. 6 (i), for example, a blue pixel color filter layer 15 b and a red pixel color filter layer 15 c are sequentially arranged in a predetermined repeated color array in the same manner as the green pixel color filter layer 15 a. To form. At this time, the order in which the pixel color filter layers 15a to 15c are formed is not particularly limited.

  Next, as shown in FIG. 6 (j), a planarizing film 16 made of acrylic thermosetting resin or acrylic thermomelting resin is applied to the upper surface on which a plurality of pixel color filter layers 15 are formed in an array. It is formed by subsequent thermosetting.

  Next, as shown in FIG. 6J, a microlens material layer made of a positive photoresist is applied to form a microlens material layer 29.

  Next, as shown in FIG. 6 (j), after the microlens material layer 29 is developed and patterned by photolithography and etching, the light absorbing ability of the photosensitizer contained in the photoresist is lost using ultraviolet rays. An exposure process (breaching exposure) to be activated is performed, and then molded into a microlens shape by thermal reflow to obtain an array of microlenses 17.

  FIG. 7 is a flowchart showing a part of a process for producing a CCD solid-state imaging device based on a modification of the first embodiment. This modification mainly corresponds to claims 10 and 28, and a metal thin film layer 19 such as aluminum, tungsten, silver, or the like is provided on the side surface of the partition 13 as the light reflecting layer.

  FIG. 7A shows the same state as FIG. 4D in which the partition 13 is formed on the silicon nitride film 12. In the modification, next, as shown in FIG. 7B, a metal thin film 18 such as aluminum or tungsten is formed on the entire surface by sputtering or the like.

  Next, the metal thin film 18 is etched back and removed, leaving only the metal thin film 19 formed on the side surface of the partition 13 as shown in FIG.

  When a light reflecting layer such as a metal thin film 19 is provided on the side surface of the partition 13, the light reaching the partition 13 out of the light incident on the pixel color filter layer 15 in the light receiving region 14 of the unit cell is reflected. In addition, since the light is guided toward the center of the photosensor unit 3, the light collection efficiency is improved and the imaging sensitivity is improved. Furthermore, since there is no light transmitted to the adjacent unit cells, the color mixture component is eliminated and the color unevenness is reduced. Naturally, even when the partition 13 is made of a material other than polycrystalline silicon, a light reflecting layer such as the metal thin film 19 can be effectively provided.

  As described above, according to the present embodiment, the pixel color filter 15 serving as the filter unit is separated for each unit cell by the partition 13 and has a shape, rectangle, or shape along the inner wall surface of the bowl-shaped partition 13. Since it is formed in a substantially rectangular shape, even if the number of pixels of the CCD solid-state imaging device is increased and the unit cell is miniaturized, inconveniences such as deterioration of the shape of the filter part and deterioration of spectral characteristics due to the deterioration are hardly caused. Further, the shape of the pixel color filter 15 becomes uniform, and the variation in optical characteristics for each unit cell is reduced.

  In addition, the pixel color filter 15 is formed by self-alignment when the reflowed dye-containing photoresist is brought into close contact with the saddle shape of the partition 13, so that the pixel color filter 15 is accurately aligned with the partition 13 by photolithography. Since a patterning process is not required, a CCD solid-state imaging device can be manufactured at a low cost and with a high productivity, a high manufacturing yield, and a process that does not require much exposure accuracy. On the other hand, in the method of Patent Document 2, it is necessary to accurately perform patterning exposure with the partition body 13 as a boundary in all unit cells, and it is practically performed in a CCD solid-state imaging device having the number of pixels reaching one million pixels. Impossible.

  Further, since the dye-containing photoresist is used as the filter material, the filter material can be easily disposed in a predetermined unit cell region by lithography and etching.

  Further, a multicolor color filter can be easily configured by the pixel color filter 15 having different transmission wavelength characteristics, and the pixel color filters 15a to 15c corresponding to the three primary colors of R (red), G (green), and B (blue). Can be obtained, a full-color CCD solid-state imaging device can be obtained.

Embodiment 2
The second embodiment mainly corresponds to claims 8 and 11 and claims 26 and 29, and a high refractive index material layer is disposed in the light transmission region, and a low refractive index material layer is provided around the high refractive index material layer. The light that leaks from the light transmitting region with a large refractive index is totally reflected at the boundary between the high refractive index material layer and the low refractive index material layer, and the light leaks from the light transmitting region. Thus, a structure having the same effect as that of an optical waveguide structure for guiding light in a certain direction is realized in the light transmission region, and a CCD solid-state imaging device having excellent sensitivity characteristics and spectral color characteristics is obtained.

  FIG. 8 is a cross-sectional view showing the structure of the CCD solid-state imaging device 30 based on the second embodiment. This sectional view is a sectional view at a position corresponding to the sectional view of the CCD solid-state imaging device 20 of FIG. The CCD solid-state imaging device 30 is different from the CCD solid-state imaging device 20 in the structure of the following two parts.

  First, in the multicolor color filter, the partition body 34 that partitions and separates the pixel color filters 15 is formed of a low refractive index material (n = 1.1 to 1.3) such as porous silica. It has been done. This refractive index is much smaller than the refractive index of the dye-containing photoresist constituting the pixel color filter 15 (approximately n = 1.6). In this way, a structure similar to an optical waveguide is formed in which the pixel color filter 15 having a high refractive index is surrounded by a partition having a low refractive index. As a result, the light that is about to leak out from the pixel color filter 15 having a high refractive index enters the partition 34 having a low refractive index, and is easily reflected and returned to the pixel color filter 15, thereby leaking light. Suppression is suppressed.

  The other one is a base region of the pixel color filter 15, and a region similar to the above optical waveguide is also formed in the region between the pixel color filter 15 and the photosensor 3 or the light shielding film 10. That is.

  That is, in the base region, in the CCD solid-state imaging device 20 shown in FIG. 1, the reflow film 11 and the silicon nitride film 12 are continuously provided without separating each unit cell. In the CCD solid-state imaging device 30 shown in FIG. 8, only a silicon nitride film 31 (n = about 1.9 to 2.0) by a plasma CVD method, which is a high refractive index material layer, is disposed. Further, a partition 32 having a function similar to that of the partition 34 is formed using porous silica which is a low refractive index material so that the silicon nitride film 31 is separated for each unit cell.

  As a result, light that is about to leak out from the light transmission region made of the silicon nitride film 31 having a high refractive index enters the partition 32 having a low refractive index, and is easily reflected and returned to the light transmission region. , Light leakage is suppressed.

  As described above, the light incident on the pixel color filter 15 is efficiently incident on the pixel color filter 15 by the optical waveguide similar structure provided in two steps continuously in the light transmission direction. Led to. As a result, the sensitivity characteristics of the CCD solid-state imaging device 30 are improved, and light transmitted to the adjacent unit cell regions is reduced, so that color mixing between adjacent unit cells can be suppressed.

  Hereinafter, a manufacturing process of the above structure will be described.

  First, after the light shielding film 10 is formed, a silicon nitride film 31 is formed on the gate insulating film 2 and the light shielding film 10 above the photosensor 3 by a plasma CVD method. Thereafter, the surface is planarized by a CMP method, or a photoresist is applied over the entire surface, and then the entire surface is etched back (see Japanese Patent Publication No. 2000-164837). Thus, only the silicon nitride film 31 (n = about 1.9 to 2.0) by the plasma CVD method, which is a high refractive index material layer, is disposed in the light transmission region from the pixel color filter 15 to the photosensor 3. Can be.

  Next, a photoresist is applied on the silicon nitride film 31 and patterned into a shape having an opening corresponding to the partition 32 by photolithography and etching. Next, a trench having a depth corresponding to the partition 32 and reaching the light shielding film 10 is formed in the silicon nitride film 31 by dry etching using the photoresist as a mask. Next, a porous silica film is formed on the silicon nitride film 31 so as to fill the groove. Porous silica is a low-k material that is generally used for semiconductor applications. A dispersion in which porous silica is dispersed in a solvent is applied by a known spin coating method and then thermally cured. Film. Thereafter, dry etching is performed on the entire surface up to the position of the surface of the silicon nitride film 31 to remove the porous silica on the silicon nitride 31 and leave only the porous silica embedded in the groove portions, thereby forming the partition bodies 32. Instead of the etch back, the surface of the silicon nitride film 31 may be polished and planarized by the CMP method.

  Next, a planarizing film 33 is formed to a thickness of about 100 to 300 nm on the silicon nitride film 31 on which the partition bodies 32 are formed. The planarizing film 33 functions as an etching stopper when the partition body 34 is formed by dry etching. The material of the planarizing film 33 is preferably a material that can be formed at a temperature lower than the heat resistant temperature of porous silica, for example, silicon nitride formed by a plasma CVD method.

  Next, the partition body 34 is formed in the same manner as described above with reference to FIGS. First, a porous silica solution is applied on the planarizing film 33 and then thermally cured to form a partition material layer that is formed into a partition body 34 in a later step. Then, a resist pattern corresponding to the arrangement position of the partition body 34 is formed by photolithography, and then the partition material layer is dry-etched using the resist pattern as a mask to form the partition body 34 made of porous silica.

  Thereafter, the description is omitted because it is exactly the same, but a multicolor color filter and a microlens are formed as described with reference to FIGS. 5 (e) to 6 (l) in the first embodiment. .

  As described above, according to the present embodiment, imaging sensitivity is improved and color mixing is performed by forming a structure similar to an optical waveguide using a material having a different refractive index in the light transmission region of each unit cell. Ingredients are reduced and color unevenness is reduced.

  Since the other points are the same as those of the first embodiment, it is needless to say that the same effects as those of the embodiment can be obtained in the present embodiment. That is, the pixel color filter 15 is separated for each unit cell by the partition body 34 and formed into a shape, a rectangle, or a substantially rectangular shape along the inner wall surface of the bowl-shaped partition body 34, so that the number of pixels of the CCD solid-state imaging device increases. Even if the unit cell is miniaturized, inconveniences such as deterioration of the shape of the filter part and deterioration of spectral characteristics due to the deterioration are unlikely to occur. Further, the shape of the pixel color filter 15 becomes uniform, and the variation in optical characteristics for each unit cell is reduced.

  In addition, the pixel color filter 15 is formed by self-alignment when the reflowed dye-containing photoresist is brought into close contact with the saddle shape of the partition body 34. Therefore, the pixel color filter 15 is accurately formed according to the partition body 34 by photolithography. Since a patterning process is not required, a CCD solid-state imaging device can be manufactured at a low cost and with a high productivity, a high manufacturing yield, and a process that does not require much exposure accuracy. On the other hand, in the method of Patent Document 2, it is necessary to accurately perform patterning exposure with the partition body 34 as a boundary in all unit cells, and it is practically performed in a CCD solid-state imaging device having the number of pixels reaching one million pixels. Impossible.

  Further, since the dye-containing photoresist is used as the filter material, the filter material can be easily disposed in a predetermined unit cell region by lithography and etching.

  Further, a multicolor color filter can be easily configured by the pixel color filter 15 having different transmission wavelength characteristics, and the pixel color filters 15a to 15c corresponding to the three primary colors of R (red), G (green), and B (blue). Can be obtained, a full-color CCD solid-state imaging device can be obtained.

Embodiment 3
The third embodiment mainly corresponds to claims 4 and 20. That is, the third embodiment is a CCD solid-state imaging device including the optical filter made of the negative type chemically amplified photoresist containing a dye as an example of an optical device including the second optical filter of the present invention. The present invention relates to an element and a manufacturing method thereof.

  In the present embodiment, the optical filter portion constituting the optical filter is molded not by reflow of the dye-containing photoresist, but by the negative type chemically amplified photoresist containing the dye, as compared with the first embodiment. The only difference is in the exposure and the subsequent heat treatment. The following description will be given with emphasis on the differences from the first embodiment.

  The negative chemically amplified photoresist is, for example, a mixture of an alkali-soluble resin, an acid generator (PAG), a crosslinking agent, a solvent, and the like (see, for example, JP-A-2003-121999). Examples of the alkali-soluble resin include novolak resin and polyvinyl phenol. An acid generator is a compound that generates an acid (hydrogen ion) upon absorption of radiation such as ultraviolet light or an electron beam. Examples thereof include sulfonate compounds such as p-toluenesulfonate. The crosslinking agent is a compound capable of crosslinking an alkali-soluble resin in the presence of an acid, and examples thereof include melamine compounds such as a methylol group-containing melamine compound.

  When this chemically amplified photoresist is exposed to radiation such as ultraviolet light, an acid (hydrogen ion) is generated from the acid generator that has absorbed the radiation, and the nearby alkali-soluble resin is affected by the cross-linking agent due to the influence of acid catalysis. Cross-linked.

  Subsequently, when post-exposure heating (PEB; Post Exposure Bake) is performed, the crosslinking reaction in the presence of an acid is activated, and the exposed region becomes insoluble. Further, when the heated acid (hydrogen ions) diffuses, a region where a crosslinking reaction proceeds also forms in the non-exposed region adjacent to the exposed region. As a result, the heating time for PEB heating becomes longer, and the insolubilized area expands from the exposed area toward the non-exposed area.

  9 and 10 are flowcharts showing a part of the manufacturing process of the CCD solid-state imaging device based on the third embodiment. FIG. 9A shows the same state as FIG. 4D in which the partition 13 is formed on the silicon nitride film 12. Here, the steps from this state to the formation of a state corresponding to the state shown in FIG. 9 and 10 are cross-sectional views at positions corresponding to the cross-sectional view of FIG.

  First, as shown in FIG. 9B, a negative chemically amplified photoresist layer 51 containing one of a plurality of colors, for example, a green dye, is formed on the entire surface by a coating method or the like. However, the thickness is not more than the height of the partition 13 so that the chemically amplified photoresist layer 51 in each light receiving region 14 is separated by the partition 13.

  Next, as shown in FIG. 9C, using the mask 52, the chemically amplified photoresist layer 51 of the unit cell 53 in which the green pixel color filter layer 41a is provided is exposed. At this time, the exposure is performed so that the non-exposure area 55 slightly enters the light receiving area of the unit cell 53 instead of exposing the section 13 as a boundary as in the method of Patent Document 2. That is, the exposure is performed so that the horizontal position of the opening of the mask 52 is inside the inner wall surface of the partition 13 in the unit cell 53. In this way, the chemically amplified photoresist layer 51 can be patterned and exposed to the inside of the partition 13 with a sufficient margin for misalignment, and the adjacent unit cell region can be erroneously patterned and exposed, or the adjacent unit cell can be exposed. It is possible to avoid adversely affecting the region due to scattering of irradiation light.

  Next, as shown in FIG. 10D, when post-exposure heating (PEB) is performed, the crosslinking reaction in the presence of an acid is activated, and the exposed region 54 is insolubilized. In addition, a region 56 in which an acid (hydrogen ion) diffuses and a crosslinking reaction proceeds is formed in a non-exposed region adjacent to the exposed region 54. As a result, when the PEB heating time is sufficiently long, the chemically amplified photoresist layer 51 existing in the non-exposed region 56 between the exposed region 54 and the partition 13 can be insolubilized. In this way, the chemically amplified photoresist layer 51 containing the green dye is automatically formed into a shape along the inner wall surface, for example, a rectangular parallelepiped shape having a rectangular section, using the partition 13 as a mold. The pixel color filter layer 41a is formed.

  Next, as shown in FIG. 10E, development processing is performed using an alkaline developer, and the chemically amplified photoresist layer 51 that has not been insolubilized is removed. Subsequently, in order to decompose the photosensitizer contained in the pixel color filter layer 41a and deactivate the light absorption ability, exposure processing (bleaching exposure) is performed using ultraviolet rays.

  Next, as shown in FIG. 10F, in the same manner as the green pixel color filter layer 41a, for example, the blue pixel color filter layer 41b and the red pixel color filter layer 41c are sequentially arranged in a predetermined repeated color array. Place and form. At this time, the order in which the pixel color filter layers 41a to 41c are formed is not particularly limited.

  As described above, according to the present embodiment, the pixel color filter 15 is molded by the unexposed chemical amplification type photoresist layer being in close contact with the saddle shape of the partition 13 and being insolubilized in that state. Since alignment is performed, a process of accurately patterning the pixel color filter 15 according to the partition 13 by photolithography is not necessary. Therefore, a process that does not require much exposure accuracy, high productivity, high manufacturing yield, and low A CCD solid-state imaging device can be manufactured at low cost.

  Since the other points are the same as those of the first embodiment, it is needless to say that the same effects as those of the embodiment can be obtained in the present embodiment. That is, the pixel color filter 41 as the filter section is separated for each unit cell by the partition 13 and is formed into a shape along the inner wall surface of the bowl-shaped partition 13, a rectangle, or a substantially rectangular shape. Even if the number of pixels increases and the unit cell becomes smaller, inconveniences such as the deterioration of the shape of the filter portion and the deterioration of the spectral characteristics due to the deterioration are unlikely to occur. In addition, the shape of the pixel color filter 41 becomes uniform, and variations in optical characteristics between unit cells are reduced.

  Further, a multicolor color filter can be easily configured by the pixel color filter 15 having different transmission wavelength characteristics, and the pixel color filters 15a to 15c corresponding to the three primary colors of R (red), G (green), and B (blue). Can be obtained, a full-color CCD solid-state imaging device can be obtained.

  As mentioned above, although this invention was demonstrated based on embodiment, it cannot be overemphasized that this invention is not limited to these examples at all, and can be suitably changed in the range which does not deviate from the main point of invention.

  In the optical device with an optical filter according to the present invention, the optical filter is separated into filter units for each unit cell by the partition body, and the filter portion is formed in a shape along the inner wall surface of the partition body, for example, rectangular or almost rectangular. Even if the number of pixels of an optical device such as a solid-state image sensor increases and the unit cell becomes smaller, inconveniences such as a deterioration in the shape of the filter part and a deterioration in spectral characteristics due to the deterioration are unlikely to occur. In addition, since the process of accurately patterning the filter portion in accordance with the partition body by photolithography is unnecessary, the optical apparatus with an optical filter can be manufactured with high productivity, good manufacturing yield, and low cost in a process that does not require much exposure accuracy. Can be manufactured. As a result, the present invention can contribute to miniaturization and high performance of a CCD solid-state imaging device and a liquid crystal display device.

It is a top view of the CCD solid-state image sensor based on Embodiment 1 of this invention. It is sectional drawing of a CCD solid-state image sensor similarly. FIG. 4 is a cross-sectional view (a) and a potential diagram (b) of the silicon substrate of the CCD solid-state imaging device. It is a flowchart which shows a part of manufacturing process of a CCD solid-state image sensor similarly. It is a flowchart which shows a part of manufacturing process of a CCD solid-state image sensor similarly. It is a flowchart which shows a part of manufacturing process of a CCD solid-state image sensor similarly. It is a flowchart which shows a part of manufacturing process of the CCD solid-state image sensor based on a modification similarly. It is sectional drawing of the CCD solid-state image sensor based on Embodiment 2 of this invention. It is a flowchart which shows a part of manufacturing process of the CCD solid-state image sensor based on Embodiment 3 of this invention. It is a flowchart which shows a part of manufacturing process of a CCD solid-state image sensor similarly. It is sectional drawing which shows the formation method of the conventional multicolor filter array currently disclosed by patent document 1. FIG. It is sectional drawing explaining the problem of the formation method of the conventional multicolor color filter currently disclosed by patent document 1. FIG. It is the microscope picture (a) which shows an example of the cross-sectional shape of the conventional color filter, and the graph (b) which shows an example of a spectral characteristic. It is sectional drawing of the solid-state image sensor currently disclosed by patent document 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Gate insulating film, 3 ... Photosensor part,
4 ... n-type region of vertical transfer portion, 5 ... overflow drain region,
6 ... 1st gate electrode (vertical transfer electrode), 7 ... 2nd gate electrode (vertical transfer electrode),
8 ... insulating film, 9 ... vertical transfer part, 10 ... light shielding film (tungsten, etc.),
11 ... Reflow film (BPSG etc.), 12 ... Silicon nitride film, 13 ... Partition body,
14 ... light receiving area, 15 ... pixel color filter layer,
15a ... Pixel color filter layer (green), 15b ... Pixel color filter layer (blue),
15c ... Pixel color filter layer (red), 16 ... Flattened film, 17 ... Microlens,
18, 19 ... Metal thin film, 20 ... CCD solid-state imaging device, 21 ... Partition material layer,
22 ... resist pattern, 23 ... dye-containing photoresist layer, 24 ... mask,
25: Unit cell for providing a green pixel color filter layer, 26: Non-exposed area,
27 ... exposure region, 28 ... dye-containing photoresist disposed in the light receiving region,
29 ... a microlens material layer, 30 ... a CCD solid-state imaging device, 31 ... a silicon nitride film,
32 ... partition body, 33 ... flattening film, 34 ... partition body,
41a ... Pixel color filter layer (green), 41b ... Pixel color filter layer (blue),
41c ... pixel color filter layer (red), 51 ... chemically amplified photoresist layer,
52... Mask, 53... Unit cell provided with a green pixel color filter layer, 54.
55 ... non-exposed area, 56 ... acid diffusion area (non-exposed area), 101 ... undercoat layer,
102 ... Yellow dye-containing resist, 103 ... First mask, 104 ... Second mask,
105 ... Yellow filter, 106 ... White filter, 107 ... Cyan color filter,
108: Green filter, 109: Multicolor filter, 110: CCD image sensor,
111 ... Silicon substrate, 112 ... Photosensor part, 113 ... First gate electrode,
114: planarizing film, 115a: pixel color filter (green),
115b ... pixel color filter (blue), 115c ... pixel color filter (red),
116: Microlens, 120: CCD image sensor, 121 ... Silicon substrate,
122: Gate insulating film, 123: Photo sensor portion, 124: First gate electrode,
125 ... insulating film, 126 ... reflow film, 127 ... light shielding metal film (photoshield),
128 ... Passivation film, 131 ... Metal thin film, 132 ... Pixel color filter layer,
133 ... Microlens

Claims (33)

An optical device including an optical filter on a light incident side or a light emitting side of a photoelectric conversion unit or a light modulation unit, wherein the optical filter is
A partition that separates the filter units corresponding to the unit cell regions on the light incident side or the light emitting side of the photoelectric conversion unit or the light modulation unit;
An optical device with an optical filter, comprising: the filter unit that is arranged in a region surrounded by the partition and is made of a filter material that is in close contact with the partition by reflow.   The optical device with an optical filter according to claim 1, wherein the partition body is made of a material that is not deformed by the reflow.   The optical device with an optical filter according to claim 1, wherein the filter material is made of a dye-containing photoresist. An optical device including an optical filter on a light incident side or a light emitting side of a photoelectric conversion unit or a light modulation unit, wherein the optical filter is
A partition that separates the filter units corresponding to the unit cell regions on the light incident side or the light emitting side of the photoelectric conversion unit or the light modulation unit;
An optical device with an optical filter, comprising: a filter portion made of a negative-type chemically amplified photoresist that is disposed in a region surrounded by the partition and is adhered and cured to the partition by a chemical amplification action.   The optical device with an optical filter according to claim 1 or 4, wherein the optical filter is configured by a plurality of types of the filter units having different light transmission characteristics.   The optical device with an optical filter according to claim 5, wherein the optical filter is configured as a multicolor color filter having different transmission wavelength characteristics.   The optical device with an optical filter according to claim 1, wherein the partition is formed as a wall portion of a frame-like pattern.   The optical device with an optical filter according to claim 1, wherein the partition body is made of a material having a refractive index smaller than that of the filter material.   The optical device with an optical filter according to claim 8, wherein the partition body is made of porous silica.   The optical device with an optical filter according to claim 1, wherein a light reflection layer is provided on a side surface of the partition body.   In the unit cell region, as a base of the optical filter, a high refractive index material layer is disposed in a light transmission region between the photoelectric conversion unit or the light modulation unit, and a low refractive index is formed around the high refractive index material layer. The optical device with an optical filter according to claim 1, wherein a material layer is disposed.   The optical device with an optical filter according to claim 11, wherein the high refractive index material layer is made of silicon nitride, and the low refractive index material layer is made of porous silica.   The optical device with an optical filter according to claim 11, wherein a stopper layer for etching the partition is formed between the base and the optical filter.   The optical device with an optical filter according to claim 1, wherein a microlens is provided for each unit cell on a light incident side or a light emitting side of the pixel filter.   An optical apparatus comprising the optical filter according to claim 1 or 4 configured as a solid-state imaging device. A method for manufacturing an optical device with an optical filter according to claim 1,
Forming a partition that separates the unit cell regions on the light incident side or light emission side of the photoelectric conversion unit or light modulation unit;
Providing the filter material in a region surrounded by the partition;
A method of manufacturing an optical device with an optical filter, comprising: heating the filter material to a predetermined temperature and reflowing the filter material.   The optical device with an optical filter according to claim 16, wherein the partition body is formed of a material that does not deform during the reflow.   The method for manufacturing an optical device with an optical filter according to claim 16, wherein a dye-containing photoresist is used as the filter material.   The optical device with an optical filter according to claim 18, wherein the filter material is patterned by lithography and etching after application of the dye-containing photoresist so that an outer surface is present at a position away from an inner wall surface of the partition. Manufacturing method. A method for manufacturing an optical device with an optical filter according to claim 4,
Forming a partition that separates the unit cell regions on the light incident side or light emission side of the photoelectric conversion unit or light modulation unit;
Providing a negative chemically amplified dye-containing photoresist on the entire surface of at least the light receiving region surrounded by the partition;
Exposing the chemically amplified photoresist present inside the compartment; and
And a step of insolubilizing the unexposed chemically amplified photoresist existing between the exposed chemically amplified photoresist and the partition by heat treatment.   21. The method of manufacturing an optical device with an optical filter according to claim 20, wherein the unexposed chemically amplified photoresist existing outside a predetermined unit cell region is removed.   21. The method for manufacturing an optical device with an optical filter according to claim 20, wherein the chemically amplified photoresist is exposed excluding a contact region with an inner wall surface of the partition.   21. The method for manufacturing an optical device with an optical filter according to claim 16 or 20, wherein the optical filter includes a plurality of types of the filter units having different light transmission characteristics.   The method for manufacturing an optical device with an optical filter according to claim 23, wherein the optical filter is configured as a multicolor color filter having different transmission wavelength characteristics.   The manufacturing method of the optical apparatus with an optical filter according to claim 16 or 20, wherein the partition is formed as a wall portion of a frame-like pattern.   The method for manufacturing an optical device with an optical filter according to claim 16 or 20, wherein the partition is formed of a material having a refractive index smaller than that of the pixel filter.   27. The method for manufacturing an optical device with an optical filter according to claim 26, wherein the partition body is formed of porous silica.   The method for manufacturing an optical device with an optical filter according to claim 16 or 20, wherein a light reflecting layer is provided on a side surface of the partition.   In the unit cell region, as a base of the optical filter, a high refractive index material is disposed in a light transmission region between the photoelectric conversion unit or the light modulation unit, and a low refractive index material is disposed around the high refractive index material layer. The method for producing an optical device with an optical filter according to claim 16 or 20, wherein the layer is disposed.   30. The method for manufacturing an optical device with an optical filter according to claim 29, wherein the high refractive index material layer is formed using silicon nitride, and the low refractive index material layer is formed using porous silica.   30. The optical device with an optical filter according to claim 29, wherein a stopper layer for etching the partition is formed between the base and the optical filter.   21. The method of manufacturing an optical device with an optical filter according to claim 16 or 20, wherein a microlens is provided for each unit cell on a light incident side or a light emitting side of the pixel filter.   The manufacturing method of the optical apparatus with an optical filter according to claim 16 or 20, which manufactures a solid-state imaging device.