Patent Publication Number: US-2011074991-A1

Title: Solid-state image device and method of manufacturing the same

Description:
FIELD OF THE INVENTION 
     The present invention relates to a solid-state image device in which a plurality of light receiving elements formed on a semiconductor substrate each have a color filter and a microlens, and a method of manufacturing the same. 
     BACKGROUND OF THE INVENTION 
     In recent years, the number of pixels in a solid-state image device has increased and digital still cameras and mobile phone cameras have decreased in size. 
     Referring to  FIGS. 13(   a ) and  13 ( b ) and  14 ( a ) and  14 ( b ), a solid-state image device of the related art will be described below. 
       FIGS. 13(   a ) and  13 ( b ) show the color filter configuration of the solid-state image device of the related art.  FIG. 13(   a ) shows the configuration of color filters and  FIG. 13(   b ) shows the pattern of a mask used for forming the color filters.  FIGS. 14(   a ) and  14 ( b ) are explanatory sectional views showing color mixture from an adjacent pixel in the solid-state image device of the related art.  FIG. 14(   a ) shows adjacent pixels of different colors and  FIG. 14(   b ) shows Green pixels. 
       FIG. 13(   a ) is a top view showing the color filters of the solid-state image device. In the solid-state image device of the related art, Green filters  106  are arranged in a checkered pattern and Blue filters  105  and Red filters  107  are alternately arranged between the Green filters  106 . As shown in  FIG. 13(   b ), in the mask pattern for forming the Green filters  106  in a checkered pattern, gaps are formed at opposite corners on the mask and the corners of rectangular patterns are cut off to increase a focus margin (e.g., see Japanese Patent Publication No. 8-8344). 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     In the related art, however, cells have decreased in size as digital still cameras and mobile phone cameras have recently decreased in size with higher pixel density. Further, skew ray components from adjacent pixels have increased as the exit pupils of camera lenses have decreased. Thus it has become necessary to address color mixture from adjacent pixels.  FIGS. 14(   a ) and  14 ( b ) are sectional views showing the valid pixels of the solid-state image device.  FIG. 14(   a ) is taken along line A-A′ of  FIG. 13(   a ) and  FIG. 14(   b ) is taken along line B-B′ of  FIG. 13(   a ). As shown in  FIG. 14(   b ), since the gaps are formed at the opposite corners of the Green filters  106 , incident light  111  of white light condensed through a microlens  110  is diagonally incident on a light receiving portion  101  from the adjacent Green filter  106  and causes color mixture. Further, as shown in  FIG. 14(   a ), color mixture from adjacent pixels occurs also in vertical and horizontal directions such that the incident light  111  of the white light condensed through the microlens  110  is diagonally incident on the Green filter  106  from an adjacent Blue filter  105  and reaches the light receiving portion  101  of the Green filter  106 . Such color mixture results in deterioration of characteristics, e.g., line crawl. 
     In view of the problem, an object of the present invention is to prevent deterioration of image characteristics by suppressing color mixture while keeping sensitivity characteristics. 
     Means for Solving the Problem 
     In order to attain the object, a solid-state image device of the present invention includes: a plurality of light receiving portions formed on a substrate; Green filters formed in a checkered pattern on the light receiving portions; Blue filters and Red filters formed in alternate lines such that the Blue filters and the Red filters are placed between the Green filters in the alternate lines; a microlens formed on each of the Green filters, the Blue filters, and the Red filters; and first light shielding films for preventing color mixture, the first light shielding film being formed in a gap between the Green filters adjacent to each other in a diagonal direction. 
     Preferably, the solid-state image device further includes second light shielding films for preventing color mixture, wherein the second light shielding films are formed on the boundaries between the Blue filters and the Green filters and the boundaries between the Red filters and the Green filters, and the second light shielding film is smaller in thickness than the first light shielding film for preventing color mixture. 
     The first light shielding film for preventing color mixture may be a Black filter. 
     The first light shielding film for preventing color mixture and the second light shielding film for preventing color mixture may be Black filters. 
     The first light shielding film for preventing color mixture may be a film made up of the Blue filter and the Red filter. 
     The first light shielding film for preventing color mixture and the second light shielding film for preventing color mixture may be films each of which is made up of the Blue filter and the Red filter. 
     The Blue filter and the Red filter may be stacked. 
     A method of manufacturing a solid-state image device of the present invention, the solid-state image device including: a plurality of light receiving portions constituting a light receiving surface; color filters; and microlenses, the color filters and microlenses corresponding to the respective light receiving portions, when the color filters are formed, the method including the steps of: forming Green filters in a checkered pattern; forming first Black filters in gaps between the Green filters adjacent to each other in a diagonal direction; and forming Blue filters and Red filters. 
     Preferably, the method further includes the step of forming second Black filters on the boundaries between the Blue filters and the Green filters and the boundaries between the Red filters and the Green filters, concurrently with the step of forming the first Black filters, the second Black filter being smaller in thickness than the first Black filter. 
     The first Black filter may be replaced with a laminate of the Blue filter and the Red filter. 
     The first Black filter and the second Black filter may be each replaced with a laminate of the Blue filter and the Red filter. 
     A method of manufacturing a solid-state image device of the present invention, the solid-state image device including: a plurality of light receiving portions constituting a light receiving surface; color filters; and microlenses, the color filters and microlenses corresponding to the respective light receiving portions, when the color filters are formed, the method including the steps of: forming second Red filters acting as first light shielding films for preventing color mixture such that the second Red filters are formed in gaps between Green filters adjacent to each other in a diagonal direction, concurrently with first Red filters acting as the color filters; forming second Blue filters acting as the first light shielding films for preventing color mixture such that the second Blue filters are formed in the gaps between the Green filters adjacent to each other in the diagonal direction, concurrently with first Blue filters acting as the color filters; and forming the Green filters in a checkered pattern such that the first light shielding films for preventing color mixture are disposed in the gaps between the Green filters adjacent to each other in the diagonal direction, wherein the first light shielding film for preventing color mixture is configured such that the second Blue filter and the second Red filter are arranged in parallel. 
     Preferably, the method further includes the steps of: forming third Red filters on the boundaries between the first Blue filters and the Green filters in the step of forming the first and second Red filters, the third Red filter acting as a second light shielding film for preventing color mixture; and forming third Blue filters on the boundaries between the first Red filters and the Green filters in the step of forming the first and second Blue filters, the third Blue filter acting as the second light shielding film for preventing color mixture, wherein the second light shielding film for preventing color mixture is smaller in thickness than the first light shielding film for preventing color mixture. 
     ADVANTAGE OF THE INVENTION 
     As previously mentioned, light shielding films for preventing color mixture are disposed between Green filters such that the light shielding films are located on the opposite corners of the Green filters arranged in a checkered pattern, thereby preventing color mixture caused by light diagonally incident from an invalid region between the Green filters adjacent to each other in a diagonal direction of the Green filter. Since the light shielding films for preventing color mixture are further disposed on the vertical and horizontal boundaries between adjacent pixels, it is possible to prevent the incident light reflected on the light shielding film formed on a transfer electrode from being incident on a light receiving portion in the vertical and horizontal directions, thereby preventing color mixture from the adjacent pixels. Thus it is possible to suppress color mixture while keeping sensitivity characteristics, thereby preventing deterioration of image characteristics. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view showing the principle part of the configuration of a solid-state image device according to the present invention; 
         FIGS. 2(   a ) and  2 ( b ) are sectional views showing the configuration of the solid-state image device according to a first embodiment; 
         FIGS. 3(   a ) and  3 ( b ) are sectional views showing the configuration of a solid-state image device according to a second embodiment; 
         FIGS. 4(   a ) and  4 ( b ) are sectional views showing the configuration of a solid-state image device in which light shielding films are formed by stacking Red filters on Blue filters according to a third embodiment; 
         FIGS. 5(   a ) and  5 ( b ) are sectional views showing the configuration of the solid-state image device in which the light shielding films are formed by stacking the Blue filters on the Red filters according to the third embodiment; 
         FIGS. 6(   a ) and  6 ( b ) are sectional views showing the configuration of a solid-state image device according to a fourth embodiment; 
         FIGS. 7(   a ) to  7 ( j ) are process sectional views showing manufacturing process  1  of the solid-state image device according to the first embodiment; 
         FIGS. 8(   a ) to  8 ( j ) are process sectional views showing manufacturing process  2  of the solid-state image device according to the first embodiment; 
         FIGS. 9(   a ) to  9 ( j ) are process sectional views showing the manufacturing process of the solid-state image device according to the second embodiment; 
         FIGS. 10(   a ) to  10 ( f ) are process sectional views showing the manufacturing process of the solid-state image device according to the third embodiment; 
         FIGS. 11(   a ) to  11 ( f ) are process sectional views showing the manufacturing process of the solid-state image device according to the third embodiment; 
         FIGS. 12(   a ) to  12 ( j ) are process sectional views showing the manufacturing process of the solid-state image device according to the fourth embodiment; 
         FIGS. 13(   a ) and  13 ( b ) show the color filter configuration of a solid-state image device of the related art; and 
         FIGS. 14(   a ) and  14 ( b ) are explanatory sectional views showing color mixture from an adjacent pixel in the solid-state image device of the related art. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     A solid-state image device to be installed in a camera according to the present invention is applicable to a CCD image sensor, a MOS image sensor, and so on. The following will describe a CCD image sensor as an example. 
     First, referring to  FIGS. 1 to 3 , the following will schematically describe the configuration of the solid-state image device. 
       FIG. 1  is a plan view showing the principle part of the configuration of the solid-state image device according to the present invention and also a top view showing the valid pixels of the solid-state image device according to the present invention.  FIGS. 2(   a ) and  2 ( b ) are sectional views showing the configuration of a solid-state image device according to a first embodiment, taken along lines A-A′ and B-B′ of  FIG. 1 .  FIGS. 3(   a ) and  3 ( b ) are sectional views showing the configuration of a solid-state image device according to a second embodiment, taken along lines A-A′ and B-B′ of  FIG. 1 . The solid-state image device has a light receiving surface made up of light receiving elements (photodiodes) in a two-dimensional array.  FIGS. 2(   a ) and  2 ( b ) are sectional views showing the two light receiving elements disposed at the center of the light receiving surface. Arrows in  FIGS. 2(   a ) and  2 ( b ) indicate incident light  111  from a light source. 
     In  FIGS. 1 to 3(   a ) and  3 ( b ), the solid-state image device of the present invention is configured such that a flat transparent film made of a material such as BPSG  104  (boro-phospho-silicate glass) is formed on light receiving portions  101  formed on a silicon semiconductor substrate  100 . Stacked on the transparent film are: color filters made of dyes or color resists containing pigments; a transparent film  109  made of a transparent acrylic resin; and microlenses  110 . The color filters are made up of Green filters  106  arranged in a checkered pattern, Red filters  107 , and Blue filters  105 . The Red filters  107  and the Blue filters  105  are formed in alternate lines such that the Red filters  107  and the Blue filters  105  are placed between the Green filters  106  in the alternate lines. In order to reduce color mixture, light shielding films for preventing color mixture, e.g., Black filters  108  in an organic light shielding pattern are placed between the Green filters  106  such that the Black filters  108  are located on the opposite corners of the Green filters  106  arranged in the checkered pattern. Further, on the vertical and horizontal boundaries between adjacent pixels, light shielding films for preventing color mixture, e.g., Black filters  108  are formed that are smaller in thickness than the light shielding films on the opposite corners of the Green filters  106 . 
     The light shielding films for preventing color mixture are disposed between the Green filters  106  such that the light shielding films are located on the opposite corners of the Green filters  106  arranged in the checkered pattern, thereby preventing color mixture caused by the light  111  diagonally incident from an invalid region between the Green filters  106  adjacent to each other in a diagonal direction of the Green filter  106 . Since the light shielding films for preventing color mixture are also disposed on the vertical and horizontal boundaries between the adjacent pixels, it is possible to prevent the incident light  111  reflected on the light shielding film formed on a transfer electrode from being incident on the light receiving portion  101  in the vertical and horizontal directions, thereby preventing color mixture from the adjacent pixel. 
     The following will describe embodiments in accordance with the accompanying drawings. 
     First Embodiment 
     First, referring to  FIGS. 1 ,  2 ( a ) and  2 ( b ),  7 ( a ) to  7 ( j ), and  8 ( a ) to  8 ( j ), a solid-state image device and a method of manufacturing the same will be described below according to a first embodiment. 
     As shown in  FIGS. 1 and 2(   a ) and  2 ( b ), in the solid-state image device of the present invention, charge transfer electrodes  102  shielded by light shielding films  103  are formed on a silicon semiconductor substrate  100  and light receiving portions  101  are formed between the charge transfer electrodes  102  on the silicon semiconductor substrate  100 . On the charge transfer electrodes  102  and the light receiving portions  101 , a flat transparent film is formed that is made of a material such as BPSG  104  (boro-phospho-silicate glass). Stacked on the transparent film are: color filters made of dyes or color resists containing pigments; a transparent film  109  made of a transparent acrylic resin; and microlenses  110 . In order to reduce color mixture, Black filters  108  in an organic light shielding pattern are disposed as light shielding films for preventing color mixture between Green filters  106  such that the Black filters  108  are located on the opposite corners of the Green filters  106  arranged in a checkered pattern. 
     In this configuration, a gap between the Green filters  106  in a diagonal direction is rhomboid or substantially rhomboid in top view and a side of the gap is generally about 0.3 μm to 0.6 μm in dimension. The Black filter  108  formed on the gap fills the gap among the Green filter  106 , a Red filter  107 , and a Blue filter  105  and the Black filter  108  has a thickness of 0.3 μm to 1.5 μm, which ranges from the smallest thickness to the largest thickness of a present color pigment filter. The Black filter  108  filling the gap among these filters should not overlap the Green filter  106 , the Red filter  107 , or the Blue filter  105 . This is because overlapping patterns may cause a height difference resulting in uneven application of filters and flat films in the subsequent process. 
     As previously mentioned, the Black filters  108  acting as light shielding films for preventing color mixture are disposed between the Green filters  106  such that the Black filters  108  are located on the opposite corners of the Green filters  106  arranged in the checkered pattern. Thus it is possible to prevent color mixture caused by light  111  diagonally incident on the light receiving portion  101  from an invalid region between the Green filters  106  adjacent to each other in a diagonal direction of the Green filter  106 , thereby preventing deterioration of image characteristics. 
     The method of manufacturing the solid-state image device according to the first embodiment includes two methods as will be described below. 
     &lt;Method 1 of Manufacturing the Solid-State Image Device&gt; 
       FIGS. 7(   a ) to  7 ( j ) are process sectional views showing manufacturing process  1  of the solid-state image device according to the first embodiment.  FIGS. 7(   a ),  7 ( c ),  7 ( e ),  7 ( g ), and  7 ( i ) are sectional views taken along line A-A′ of  FIG. 1 .  FIGS. 7(   b ),  7 ( d ),  7 ( f ),  7 ( h ), and  7 ( j ) are sectional views taken along line B-B′ of  FIG. 1 . 
     First, as shown in  FIGS. 7(   a ) and  7 ( b ), the light receiving portions  101 , the charge transfer electrodes  102 , the light shielding films  103 , and the BPSG  104  are formed on the silicon semiconductor substrate  100 . 
     Next, as shown in  FIGS. 7(   c ) and  7 ( d ), the material of the Black filter  108  is applied with a thickness of 0.3 μm to 1.5 μm on the BPSG  104 , and is exposed and developed with a photomask so as to leave a pattern on positions corresponding to the gaps between the opposite corners of the Green filters  106 , so that the Black filters  108  are patterned. 
     After that, as shown in  FIGS. 7(   e ) and  7 ( f ), the material of the Green filter  106  is applied with a thickness of 0.3 μm to 1.5 μm, and is exposed and developed with a photomask so as to leave a pattern on the light receiving portions  101  that require the Green filters  106 , so that the Green filters  106  are patterned. 
     Next, as shown in  FIGS. 7(   g ) and  7 ( h ), the materials of the Red filter  107  and the Blue filter  105  are applied with a thickness of 0.3 μm to 1.5 μm and are exposed and developed with a photomask as in the formation of the Green filters  106 , so that the Red filters  107  and the Blue filters  105  are formed. 
     Finally, as shown in  FIGS. 7(   i ) and  7 ( j ), the transparent film  109  under the microlenses is applied with a thickness of 0.1 μm to 1.0 μm and the material of the microlens  110  is applied with a thickness of 0.5 μm to 2.0 μm and is subjected to exposure, development, bleaching, and thermal flow, so that the microlenses  110  are formed. 
     &lt;Method 2 of Manufacturing the Solid-State Image Device&gt; 
     Unlike in method 1 of manufacturing the solid-state image device, the Green filters  106  may be first formed and then the Black filters  108  may be formed on the opposite corners as will be described in manufacturing process  2  of the solid-state image device in  FIGS. 8(   a ) to  8 ( j ). 
       FIGS. 8(   a ) to  8 ( j ) are process sectional views showing manufacturing process  2  of the solid-state image device according to the first embodiment.  FIGS. 8(   a ),  8 ( c ),  8 ( e ),  8 ( g ), and  8 ( i ) are sectional views taken along line A-A′ of  FIG. 1 .  FIGS. 8(   b ),  8 ( d ),  8 ( f ),  8 ( h ), and  8 ( j ) are sectional views taken along line B-B′ of  FIG. 1 . 
     First, as shown in  FIGS. 8(   a ) and  8 ( b ), the light receiving portions  101 , the charge transfer electrodes  102 , the light shielding films  103 , and the BPSG  104  are formed on the silicon semiconductor substrate  100 . 
     Next, as shown in  FIGS. 8(   c ) and  8 ( d ), the material of the Green filter  106  is applied with a thickness of 0.3 μm to 1.5 μm on the BPSG  104 , and is exposed and developed with a photomask so as to leave a pattern on the light receiving portions  101  that require the Green filters  106 , so that the Green filters  106  are patterned. In this case, after the Green filters  106  are formed, the Black filters  108  may be formed before the Red filters  107  and the Blue filters  105 , and vice versa. 
     The present embodiment will describe, as an example, a manufacturing method in which the Black filters  108  are formed after the formation of the Green filters  106 . 
     After the Green filters  106  are formed, as shown in  FIGS. 8(   e ) and  8 ( f ), the material of the Black filter  108  is applied with a thickness of 0.3 μm to 1.5 μm, and is exposed and developed with a photomask so as to leave a pattern on the positions corresponding to the gaps between the opposite corners of the Green filters  106 , so that the pattern of the Black filters  108  is formed. 
     Next, the Red filters  107  and the Blue filters  105  are similarly formed. To be specific, as shown in  FIGS. 8(   g ) and  8 ( h ), the materials of the Red filter  107  and the Blue filter  105  are applied with a thickness of 0.3 μm to 1.5 μm and then are exposed and developed, so that the Red filters  107  and the Blue filters  105  are formed. 
     Finally, as shown in  FIGS. 8(   i ) and  8 ( j ), the transparent film  109  under the microlenses is applied with a thickness of 0.1 μm to 1.0 μm and the material of the microlens  110  is applied with a thickness of 0.5 μm to 2.0 μm and is subjected to exposure, development, bleaching, and thermal flow, so that the microlenses  110  are formed. 
     According to these methods, the Black filters  108  acting as light shielding films for preventing color mixture can be disposed between the Green filters  106  such that the Black filters  108  are located on the opposite corners of the Green filters  106  arranged in the checkered pattern. Thus it is possible to prevent color mixture caused by the light  111  diagonally incident on the light receiving portion  101  from the invalid region between the Green filters  106  adjacent to each other in a diagonal direction of the Green filter  106 , thereby preventing deterioration of image characteristics. 
     Second Embodiment 
     Referring to  FIGS. 1 ,  3 ( a ) and  3 ( b ), and  9 ( a ) to  9 ( j ), the following will describe a solid-state image device and a method of manufacturing the same according to a second embodiment. 
     On the vertical and horizontal boundaries among a Red filter  107 , a Blue filter  105 , and a Green filter  106 , incident light  111  from an adjacent pixel may be reflected on a light shielding film  103  and sensitivity may decline. In order to address this problem in the solid-state image device of the second embodiment, Black filters  112  are formed on the vertical and horizontal boundaries between adjacent pixels in the respective color filters as shown in  FIGS. 3(   a ) and  3 ( b ), unlike in the solid-state image device of the first embodiment. The Black filters  112  are smaller in thickness than Black filters  108  disposed on the opposite corners of the Green filters  106 . The Black filters  112  formed on the vertical and horizontal boundaries are 0.2 μm to 0.6 μm in dimension in plan view and are 0.3 μm to 1.3 μm in thickness. 
     In the vertical and horizontal directions, the light  111  having been condensed through microlenses  110  and incident near the boundaries may be reflected on the Black filters  112  for shielding light without being incident on light receiving portions  101 , resulting in a decline in sensitivity. For this reason, the Black filters  112  have to be smaller in thickness than the Black filters  108  disposed on the opposite corners of the Green filters  106 . Thus the Black filters  108  on the opposite corners are 0.3 μm to 1.5 μm in thickness, whereas the Black filters  112  arranged in the vertical and horizontal directions are 0.3 μm to 1.3 μm in thickness. 
     As previously mentioned, the Black filters  108  acting as light shielding films for preventing color mixture are disposed between the Green filters  106  such that the Black filters  108  are located on the opposite corners of the Green filters  106  arranged in a checkered pattern, and the Black filters  112  shorter than the Black filters  108  are provided on the boundaries between the filters and the pixels adjacent to the filters in the vertical and horizontal directions of the respective color pixels. Thus it is possible to prevent color mixture occurring when the light  111  is diagonally incident on the light receiving portion  101  from an invalid region between the Green filters  106  adjacent to each other in a diagonal direction of the Green filter  106 , and it is possible to prevent color mixture occurring when the incident light  111  is reflected on the light shielding film  103  and is incident on the light receiving portion  101  from the pixels adjacent in the vertical and horizontal directions of the respective color pixels, thereby preventing deterioration of image characteristics. 
     The following will describe the method of manufacturing the solid-state image device according to the second embodiment. 
       FIGS. 9(   a ) to  9 ( j ) are process sectional views showing the manufacturing process of the solid-state image device according to the second embodiment.  FIGS. 9(   a ),  9 ( c ),  9 ( e ),  9 ( g ), and  9 ( i ) are sectional views taken along line A-A′ of  FIG. 1 .  FIGS. 9(   b ),  9 ( d ),  9 ( f ),  9 ( h ), and  9 ( j ) are sectional views taken along line B-B′ of  FIG. 1 . 
     The steps are basically similar to those of  FIGS. 7(   a ) to  7 ( j ). The Black filters  108  for the light shielding films formed on the opposite corners of the Green filters  106  are different in thickness from the Black filters  112  for the light shielding films formed between the filters adjacent to each other in the vertical and horizontal directions. Thus the Black filters are simultaneously formed with a gray scale mask (halftone mask). 
     First, as shown in  FIGS. 9(   a ) and  9 ( b ), the light receiving portions  101 , charge transfer electrodes  102 , the light shielding films  103 , and BPSG  104  are formed on a silicon semiconductor substrate  100 . 
     Next, as shown in  FIGS. 9(   c ) and  9 ( d ), the materials of the Black filter  108  and the Black filter  112  for shielding light are applied with a thickness of 0.3 μm to 1.5 μm on the BPSG  104 , the mask of the pixel boundaries in the vertical and horizontal directions has a different gray scale from the mask of the opposite corners of the Green filters, the materials are exposed and developed with a gray scale mask to adjust an amount of irradiation during the exposure, and patterning is performed at positions corresponding to the opposite corners of the Green filters  106  and the pixel boundaries in the vertical and horizontal directions, so that the Black filters  108  and the Black filters  112  shorter than the Black filters  108  are formed. 
     After that, as shown in  FIGS. 9(   e ) and  9 ( f ), the material of the Green filter  106  is applied with a thickness of 0.3 μm to 1.5 μm, and is exposed and developed with a photomask so as to leave a pattern on the light receiving portions  101  that require the Green filters  106 , so that the Green filters  106  are patterned. 
     Next, as shown in  FIGS. 9(   g ) and  9 ( h ), the Red filters  107  and Blue filters  105  are formed like the Green filters  106 . 
     Finally, as shown in  FIGS. 9(   i ) and  9 ( j ), a transparent film  109  under microlenses is applied with a thickness of 0.1 μm to 1.0 μm and the material of the microlens  110  is applied with a thickness of 0.5 μm to 2.0 μm and is subjected to exposure, development, bleaching, and thermal flow, so that the microlenses  110  are formed. 
     According to this method, the Black filters  108  acting as light shielding films for preventing color mixture can be disposed between the Green filters  106  such that the Black filters  108  are located on the opposite corners of the Green filters  106  arranged in a checkered pattern, and the Black filters  112  shorter than the Black filters  108  can be provided on the boundaries between the filters and the pixels adjacent to the filters in the vertical and horizontal directions of the respective color pixels. Thus it is possible to prevent color mixture occurring when the light  111  is diagonally incident on the light receiving portion  101  from an invalid region between the Green filters  106  adjacent to each other in a diagonal direction of the Green filter  106 , and it is possible to prevent color mixture occurring when the incident light  111  is reflected on the light shielding film  103  and is incident on the light receiving portion  101  from the pixels adjacent in the vertical and horizontal directions of the respective color pixels, thereby preventing deterioration of image characteristics. 
     Third Embodiment 
     Referring to  FIGS. 1 ,  4 ( a ) and  4 ( b ),  5 ( a ) and  5 ( b ),  10 ( a ) to  10 ( f ), and  11 ( a ) to  11 ( f ), the following will describe a solid-state image device and a method of manufacturing the same according to a third embodiment. 
       FIGS. 4(   a ) and  4 ( b ) are sectional views showing the configuration of the solid-state image device in which light shielding films are formed by stacking Red filters on Blue filters according to the third embodiment.  FIGS. 5(   a ) and  5 ( b ) are sectional views showing the configuration of the solid-state image device in which the light shielding films are formed by stacking the Blue filters on the Red filters according to the third embodiment.  FIGS. 10(   a ) to  10 ( f ) and  11 ( a ) to  11 ( f ) are process sectional views showing the manufacturing process of the solid-state image device according to the third embodiment.  FIGS. 10(   a ),  10 ( c ),  10 ( e ),  11 ( a ),  11 ( c ), and  11 ( e ) are sectional views taken along line A-A′ of  FIG. 1 .  FIGS. 10(   b ),  10 ( d ),  10 ( f ),  11 ( b ),  11 ( d ), and  11 ( f ) are sectional views taken along line B-B′ of  FIG. 1 . 
     In the third embodiment, instead of the Black filter  108  and the Black filter  112  of the first or second embodiment, a laminate of a Blue filter  105  and a Red filter  107  is used as a light shielding film for preventing color mixture. The stacked Blue filter and Red filter can cut off light at a wavelength of about 400 nm to 500 nm and light at a wavelength of about 600 nm to 700 nm, respectively. Thus it is possible to achieve substantially the same effect as the Black filter. In this case, laminates formed on the opposite corners of Green filters have dimensions of about 0.3 μm to 0.6 μm in plan view and the laminate of the Blue filter  105  and the Red filter  107  is 0.3 μm to 1.5 μm in thickness. Moreover, laminates formed on the vertical and horizontal boundaries have dimensions of 0.3 μm to 0.6 μm in plan view and are 0.3 μm to 1.3 μm in thickness. The Blue filter  105  and the Red filter  107  may be formed in any order. 
     For example, as shown in  FIGS. 4(   a ) and  4 ( b ) and  5 ( a ) and  5 ( b ), the laminate of the Blue filter  105  and the Red filter  107  is formed instead of the light shielding films, which are formed by the Black filter  108  and the Black filter  112 , for preventing color mixture in  FIGS. 2(   a ) and  2 ( b ) and  3 ( a ) and  3 ( b ). In  FIGS. 4(   a ) and  4 ( b ) and  5 ( a ) and  5 ( b ), the constituent elements illustrated in  FIGS. 2(   a ) and  2 ( b ) and  3 ( a ) and  3 ( b ) are indicated by the same reference numerals and the explanation thereof is omitted. In the laminate of  FIGS. 4(   a ) and  4 ( b ), the Red filter  107  is stacked on the Blue filter  105 . In the laminate of  FIGS. 5(   a ) and  5 ( b ), the Blue filter  105  is stacked on the Red filter  107 . 
     Regarding the method of manufacturing the solid-state image device according to the third embodiment, a method of manufacturing the solid-state image device in  FIGS. 4(   a ) and  4 ( b ) will be described as an example. 
     First, as shown in  FIGS. 10(   a ) and  10 ( b ), light receiving portions  101 , charge transfer electrodes  102 , light shielding films  103 , and BPSG  104  are formed on a silicon semiconductor substrate  100 . 
     Next, as shown in  FIGS. 10(   c ) and  10 ( d ), the material of the Blue filter  105  is applied with a thickness of 0.3 μm to 1.5 μm on the BPSG  104 , is exposed and developed with a gray scale mask, and is patterned at positions corresponding to the opposite corners of Green filters  106 . At this point, the mask of pixel boundaries in the vertical and horizontal directions has a different gray scale from the mask of the opposite corners, an amount of irradiation during the exposure is adjusted, and a filter thickness is reduced between pixels adjacent to each other in the vertical and horizontal directions. 
     After that, as shown in  FIGS. 10(   e ) and  10 ( f ), the material of the Red filter  107  is applied with a thickness of 0.3 μm to 1.5 μm, the mask of the pixel boundaries in the vertical and horizontal directions has a different gray scale from the mask of the opposite corners, and the material is exposed and developed using a gray scale mask with an adjusted amount of irradiation during the exposure, so that the light shielding films for preventing color mixture are patterned. In the light shielding film, the Red filter  107  is stacked on the Blue filter  105 . 
     Next, as shown in  FIGS. 11(   a ) and  11 ( b ), the material of the Green filter  106  is applied with a thickness of 0.3 μm to 1.5 μm, and is exposed and developed with a photomask so as to leave a pattern on the light receiving portions  101  that require the Green filters  106 , so that the Green filters  106  are patterned. 
     After that, as shown in  FIGS. 11(   c ) and  11 ( d ), the Red filters  107  and the Blue filters  105  are formed like the Green filters  106 . 
     Finally, as shown in  FIGS. 11(   e ) and  11 ( f ), a transparent film  109  under microlenses is applied with a thickness of 0.1 μm to 1.0 μm and the material of a microlens  110  is applied with a thickness of 0.5 μm to 2.0 μm and is subjected to exposure, development, bleaching, and thermal flow, so that the microlenses  110  are formed. 
     In the manufacturing of the solid-state image device shown in  FIGS. 5(   a ) and  5 ( b ), the Blue filter  105  and the Red filter  107  are exchanged with each other in the steps of  FIGS. 10(   c ) to  10 ( f ). 
     In this way, the light shielding films, in which the Red filters  107  are stacked on the Blue filters  105 , for preventing color mixture are disposed between the Green filters  106  such that the light shielding films are located on the opposite corners of the Green filters  106  arranged in a checkered pattern, or the light shielding films, in which the Red filters  107  are stacked on the Blue filters  105 , for preventing color mixture are further provided on the boundaries between the filters and the pixels adjacent to the filters in the vertical and horizontal directions of the respective color pixels, the light shielding films being shorter than the light shielding films for preventing color mixture on the opposite corners of the Green filters  106 . Thus it is possible to prevent color mixture occurring when light  111  is diagonally incident on the light receiving portion  101  from an invalid region between the Green filters  106  adjacent to each other in a diagonal direction of the Green filter  106 , and it is possible to prevent color mixture occurring when the incident light  111  is reflected on the light shielding film  103  and is incident on the light receiving portion  101  from the pixels adjacent in the vertical and horizontal directions of the respective color pixels, thereby preventing deterioration of image characteristics. 
     Fourth Embodiment 
     Referring to  FIGS. 1 ,  6 ( a ) and  6 ( b ), and  12 ( a ) to  12 ( j ), the following will describe a solid-state image device and a method of manufacturing the same according to a fourth embodiment. 
       FIGS. 6(   a ) and  6 ( b ) are sectional views showing the configuration of the solid-state image device according to the fourth embodiment.  FIGS. 12(   a ) to  12 ( j ) are process, sectional views showing the manufacturing process of the solid-state image device according to the fourth embodiment.  FIGS. 12(   a ),  12 ( c ),  12 ( e ),  12 ( g ), and  12 ( i ) are sectional views taken along line A-A′ of  FIG. 1 . FIGS.  12 ( b ),  12 ( d ),  12 ( f ),  12 ( h ), and  12 ( j ) are sectional views taken along line B-B′ of  FIG. 1 . 
     The solid-state image device of the third embodiment is formed by stacking the Red filters  107  and Blue filters  105  for shielding light, whereas in the solid-state image device of the fourth embodiment, Red filters  107  and Blue filters  105  are arranged in parallel as shown in  FIGS. 6(   a ) and  6 ( b ) and the same effect is obtained as Black filters  108  and Black filters  112 . In this configuration, on the vertical and horizontal boundaries of the Blue filters  105  and the Red filters  107  with Green filters  106 , only the Red filters  107  are formed on the boundaries between the Blue filters  105  and the Green filters  106  and only the Blue filters  105  are formed on the boundaries between the Red filters  107  and the Green filters  106 . 
     The following will describe the method of manufacturing the solid-state image device according to the fourth embodiment. 
     First, as shown in  FIGS. 12(   a ) and  12 ( b ), light receiving portions  101 , charge transfer electrodes  102 , light shielding films  103 , and BPSG  104  are formed on a silicon semiconductor substrate  100 . 
     Next, as shown in  FIGS. 12(   c ) and  12 ( d ), the material of the Blue filter  105  or the Red filter  107  is applied with a thickness of 0.3 μm to 1.5 μm on the BPSG  104 , a mask has a different gray scale in the vertical and horizontal directions from a mask on the opposite corners of the Green filters, and the material is exposed and developed using a gray scale mask with an adjusted amount of irradiation during the exposure, so that the Blue filters  105  or the Red filters  107  are patterned. 
     After that, as shown in  FIGS. 12(   e ) and  12 ( f ), the material of the Red filter  107  (Blue filter  105 ) is applied with a thickness of 0.3 μm to 1.5 μm, and is exposed and developed using a gray scale mask, so that the Red filters  107  (Blue filters  105 ) are patterned. Consequently, light shielding films are formed on the light receiving portions  101 , the opposite corners of the Green filters  106 , and pixel boundaries in the vertical and horizontal directions. At this point, the mask of the pixel boundaries in the vertical and horizontal directions has a different gray scale from the mask of the opposite corners, and an amount of irradiation during the exposure is adjusted. 
     After the Red filters  107  (Blue filters  105 ) are formed, the Blue filters  105  (Red filters  107 ) are similarly formed. 
     In this configuration, the Red filters  107  may be simultaneously formed on the light receiving portions  101 , the opposite corners of the Green filters  106 , and the pixel boundaries in the vertical and horizontal directions by adjusting the thickness with the adjusted amount of irradiation during the exposure. Similarly, the Blue filters  105  may be simultaneously formed on the light receiving portions  101 , the opposite corners of the Green filters  106 , and the pixel boundaries in the vertical and horizontal directions by adjusting the thickness with the adjusted amount of irradiation during the exposure. 
     Next, as shown in  FIGS. 12(   g ) and  12 ( h ), the material of the Green filter  106  is applied with a thickness of 0.3 μm to 1.5 μm, and is exposed and developed with a photomask so as to leave a pattern on the light receiving portions  101  that require the Green filters  106 , so that the Green filters  106  are patterned. 
     Finally, as shown in  FIGS. 12(   i ) and  12 ( j ), a transparent film  109  under microlenses is applied with a thickness of 0.1 μm to 1.0 μm and the material of a microlens  110  is applied with a thickness of 0.5 μm to 2.0 μm and is subjected to exposure, development, bleaching, and thermal flow, so that the microlenses  110  are formed. 
     As previously mentioned, the light shielding films, each of which is made up of the Blue filter  105  and the Red filter  107 , for preventing color mixture are disposed between the Green filters  106  such that the light shielding films are located on the opposite corners of the Green filters  106  arranged in a checkered pattern, or the light shielding films, each of which is made up of the Blue filter  105  or the Red filter  107 , for preventing color mixture are further provided on the boundaries between the filters and pixels adjacent to the filters in the vertical and horizontal directions of the respective color pixels, the light shielding films being shorter than the light shielding films for preventing color mixture on the opposite corners of the Green filters  106 . Thus it is possible to prevent color mixture occurring when light  111  is diagonally incident on the light receiving portion  101  from an invalid region between the Green filters  106  adjacent to each other in a diagonal direction of the Green filter  106 , and it is possible to prevent color mixture occurring when the incident light  111  is reflected on the light shielding film  103  and is incident on the light receiving portion  101  from the pixels adjacent in the vertical and horizontal directions of the respective color pixels, thereby preventing deterioration of image characteristics. 
     INDUSTRIAL APPLICABILITY 
     The present invention is useful for a solid-state image device in which a plurality of light receiving elements formed on a semiconductor substrate each have a color filter and a microlens, and a method of manufacturing the same. The present invention can prevent deterioration of image characteristics by suppressing color mixture while keeping sensitivity characteristics.