JP2008042146A - Single ccd solid imaging element and method for manufacturing the same, and digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a color mixture in a single CCD solid imaging element where a micro lens mounted pixel and a micro lens unmounted pixel are adjacently provided. <P>SOLUTION: A boundary position between a first color color-filter and a second color color-filter is manufactured so as to arrange a positional relation to allow an incident light with the maximum angle of incident θincident upon the micro lens unmounted pixel passing through the boundary position between the first color color-filter of the micro lens mounted pixel and the second color color-filter of the micro lens unmounted pixel to be incident upon the opening end of a shielding film on the micro lens mounted pixel side out of the opening end 108a of the micro lens unmounted pixel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a single-plate solid-state imaging device, a single-plate solid-state imaging device, and a digital camera in which a microlens mounting pixel and a microlens non-mounting pixel are provided adjacently.

  In a single-plate solid-state imaging device that captures a color image, for example, as described in Patent Document 1 below, a pixel on which a microlens is mounted and a pixel on which a microlens is not mounted are arranged adjacent to each other. There is something.

  FIG. 2 is a schematic cross-sectional view of two pixels in a solid-state imaging device in which a microlens mounting pixel and a microlens non-mounting pixel are adjacent to each other. A p-well layer 2 is formed on the n-type semiconductor substrate 1, and an n-type region 3 constituting a photodiode is formed on the surface portion.

  A gate insulating film 4 is laminated on the outermost surface of the semiconductor substrate 1, and a light shielding film 5 is formed thereon. The light shielding film 5 has an opening 5a on the light receiving surface of each photodiode.

  A transparent planarizing layer 6 is laminated on the light shielding film 5, and a color filter layer 7 is laminated on the planarizing layer 6. In the illustrated example, a red (R) color filter layer is provided on the left pixel, and a green (G) color filter layer is provided on the right pixel.

  Then, a planarizing layer 8 is laminated on the color filter layer 7, and a microlens 9 is provided on the left pixel of the surface, and no microlens is provided on the right pixel.

  When the solid-state imaging device shown in FIG. 2 is viewed from above, the microlens 9 has a circular shape, and the color filters for each color are each formed in, for example, a rectangular shape or a circular shape. The color filter of each pixel is closely arranged with the color filter of the adjacent pixel.

  When the horizontal distance from the light shielding film opening end of the pixel not equipped with the micro lens to the color filter boundary of both pixels is X, and the horizontal distance from the light shielding film opening end to the end of the micro lens 9 is XML, X ≧ XML. Usually, the microlens 9 is formed as described above. That is, the microlens 9 is formed so that the end of the microlens 9 slightly protrudes to the color filter side of the adjacent non-microlens pixel.

  As a result, all the incident light to the microlens 9 is received by the photodiode through the color filter R of the pixel itself, and the incident light to the adjacent non-microlens mounting pixel that does not enter the microlens 9 The light is received by its own photodiode without passing through the color filter. That is, the microphone lens 9 is manufactured so that color mixing does not occur.

JP 2005-259750 A

  In recent years, solid-state imaging devices have been increased in number of pixels, and those having millions of pixels have become common. As the number of pixels increases, more than 10 million pixels must be manufactured on one small chip.

  As the number of pixels increases, it is necessary to manufacture each pixel minutely, and it becomes difficult to manufacture the microlenses of all the microlens mounted pixels in the state shown in FIG. This is because the positional relationship between the color filter layer and the microlens includes variations.

  For this reason, as shown in FIG. 3, the microlens 9 becomes considerably smaller than the color filter 7 of its own pixel. In the state shown in FIG. 3, obliquely incident light passes through the color filter R of the microlens mounting pixel, then enters the color filter G of the adjacent microlens nonmounting pixel through the color filter boundary, and the microlens nonmounting pixel. The photo diode receives light.

  The spectral sensitivity characteristics of the color filters R and G are not completely independent spectral characteristics (the same applies to the color filters G and B), and overlap at the bottom. For this reason, the green light that has passed through the color filter R is received by the pixels not equipped with the microlens, resulting in color mixture and poor color shading.

  An object of the present invention is to provide a method for manufacturing a single-plate solid-state imaging device that does not cause color mixing, a solid-state imaging device, and a digital camera.

  The method for manufacturing a single-plate solid-state imaging device according to the present invention is a method for manufacturing a single-plate solid-state imaging device in which a microlens mounting pixel and a microlens non-mounting pixel are provided adjacent to each other. The incident light of the maximum incident angle that enters the pixel not mounted with the microlens through the boundary position between the filter and the second color filter of the pixel not mounted with the microlens is a light shielding film opening of the pixel not mounted with the microlens. A boundary position between the first color filter and the second color filter is manufactured so as to be in a positional relationship of being incident on a light-shielding film opening end on the microlens mounted pixel side among the ends.

  In the method for manufacturing a single-plate solid-state image sensor according to the present invention, the maximum incident angle is determined by a photographing lens of a digital camera on which the single-plate solid-state image sensor is mounted.

In the method for manufacturing a single-plate solid-state imaging device according to the present invention, the horizontal distance from the light shielding film opening end on the microlens mounting pixel side to the boundary position is X, the upper surface position of the first and second color filters, and the When the vertical distance between the top surface position of the light shielding film opening end is Z and the maximum incident angle is θ,
X> Z · tanθ
The said boundary position is provided in the position which satisfy | fills.

  The method for manufacturing a single-plate solid-state imaging device according to the present invention is characterized in that the boundary position is determined by the θ determined by the photographing lens having the largest maximum incident angle among the photographing lenses that can be mounted on the digital camera.

  The method for manufacturing a single-plate solid-state imaging device according to the present invention is characterized in that the boundary position around the entire circumference of the microlens is manufactured in the positional relationship.

  The method for manufacturing a single-plate solid-state imaging device according to the present invention is characterized in that the boundary position around a part of the microlens is manufactured in the positional relationship.

  The single-plate solid-state imaging device of the present invention is manufactured by any one of the manufacturing methods described above.

  The digital camera of the present invention is characterized by mounting the above-described single-plate solid-state imaging device.

  According to the present invention, the light incident on each pixel does not pass through two color filters having different colors regardless of the manufacturing error of the microlens.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of two pixels of a solid-state imaging device mounted on a digital camera according to an embodiment of the present invention. Although the solid-state image pickup device in the illustrated example is a CCD type, this embodiment can also be applied to a MOS type solid-state image pickup device such as a CMOS.

  A solid-state imaging device 100 according to this embodiment in which a microlens mounting pixel and a microlens non-mounting pixel are provided adjacent to each other is formed on an n-type semiconductor substrate 101. A P-well layer 102 is formed on the surface portion of the semiconductor substrate 101, and an n-type region 103 constituting a photodiode and an n-type region 104 constituting a buried channel of a vertical charge transfer path (VCCD) are formed on the surface portion. And are formed alternately.

  A p-type high-concentration impurity surface layer 105 for blocking dark current is formed on the surface of the n-type region 103, and a gate insulating film 106 is laminated on the entire outermost surface of the semiconductor substrate 101. On the n-type region 104 on the gate insulating film 106, an electrode film (vertical transfer electrode film serving also as a readout electrode) 107 made of polysilicon extending to the end position of the n-type region 103 is laminated. A light shielding film 108 made of a tungsten film is laminated.

  Openings 108a are provided on the n-type region 103 of the light shielding film 108, respectively. The upper end position of the light shielding film opening 108a is defined as “a”.

  A transparent planarizing layer 110 is laminated on the light shielding film 108, and a color filter layer 111 is laminated on the planarizing layer 110. In the case of a single-plate solid-state imaging device equipped with RGB primary color filters, the color filter layer 111 is formed, for example, by forming a red filter layer having a predetermined thickness over the entire surface of the planarizing layer 110, and the red filter layer at the red pixel position. Pattern etching is performed, and then a green filter layer having a predetermined thickness is formed on the entire surface, and pattern etching is performed to leave the color filter layer at the red pixel position and the green pixel position. Finally, a predetermined thickness is formed on the entire surface. It is manufactured by forming a blue filter layer and etching so that the entire filter layer has a uniform thickness.

  The color filter layers R, G, B of each color are rectangular or circular when viewed from above, and the boundary between adjacent color filters of different colors is a photodiode (n-type region 103) as shown in FIG. The boundary position is adjusted when designing the color filter as described later.

  The position of the upper end surface of the color filter layer 111 is “b”. A planarizing layer 112 is laminated on the color filter layer 111, a microlens 113 is laminated at the pixel position where the microlens is mounted, and no microlens is provided at the pixel position where the microlens is not mounted.

  For example, the microlens 113 may be formed by dropping a liquid microlens material onto a corresponding position and solidifying it into a lens shape using the surface tension, or by laminating the microlens material over the entire surface and using a transfer technique. For example, it is manufactured by dry etching into a lens shape.

  Horizontal end of the microlens 113 mounted on the microlens mounting pixel on the adjacent microlens non-mounting pixel side and the light shielding film opening end (opening end on the microlens mounting pixel side) of the adjacent microlens nonmounting pixel. The distance is XML, the horizontal distance between the opening edge of the light shielding film and the boundary of the color filter layer between the two pixels is X, and the vertical distance between the position a and the position b is Z.

  Therefore, when manufacturing the solid-state imaging device of this embodiment, the boundaries among the R filter position, G filter position, and B filter position of the color filter layer 111 are determined as follows.

That is, in consideration of manufacturing errors of the microlens 113 and the color filter 111, even when the microlens 113 is manufactured small inside the color filter of the pixel and X ≦ XML,
X> Z · tanθ
Each color filter R, G, B and microlens is manufactured to satisfy the above.

  Here, θ is the last angle at which the obliquely incident light entering the color filter boundary from the pixel mounted with the microlens enters the opening end of the light shielding film opening 108a of the pixel not mounted with the adjacent microlens. This θ is a value determined by the photographing lens performance of the digital camera on which the solid-state image sensor 100 is mounted. If the photographing lens performance is determined, the solid-state imaging device 100 is manufactured in accordance with this θ.

  When a subject is imaged with a digital camera equipped with the solid-state imaging device 100 having such a configuration, incident light that has entered the microlens mounting pixel enters the light shielding film opening 108a of the pixel by being condensed by the microlens 113, Light is received by the photodiode. On the other hand, incident light that does not enter the light-shielding film opening 108a out of incident light that has entered the pixel not equipped with the microlens is directly hit the light-shielding film 108 and is shielded.

  In other words, the amount of incident light is larger in the pixel mounted with the microlens than in the pixel not mounted with the microlens, so that highly sensitive image data can be obtained. On the other hand, low-sensitivity image data can be obtained from a pixel not equipped with a microlens because the amount of incident light is small. Therefore, image data with a wide dynamic range can be obtained by combining both image data.

  Now, it is assumed that oblique incident light is incident on the solid-state imaging device 100. In this case, in the solid-state imaging device 100 manufactured so as to satisfy the above-described condition “X> Z · tan θ”, the light enters from the microlens mounted pixel side, passes through the boundary portion of the color filter, and is not adjacent to the microlens mounted pixel. The light incident on the color filter does not enter the light shielding film opening 108a of the pixel not equipped with the microlens and is shielded by the light shielding film 108. That is, only light that has passed through the color filter of the pixel enters the light shielding film opening 108a of the pixel not equipped with the microlens and is received by the photodiode, so that color mixing does not occur.

  Needless to say, it is preferable that the manufacturing condition “X> Z · tan θ” described above is satisfied all around the microlens 113, but it is necessary to take measures for pixels that do not need to be treated all around. The manufacturing conditions need only be applied to the end portions of the microlenses that must be provided.

  In the above-described embodiments, R (red), G (green), and B (blue) primary color filters have been described as examples. However, the above-described implementation is also applied to a single-plate solid-state imaging device using complementary color filters. Needless to say, the form is applicable.

  According to the present invention, since color mixing does not occur, it is useful when applied to a digital camera that captures a high-definition image.

It is a cross-sectional schematic diagram for 2 pixels of the single-plate-type solid-state image sensor which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram for two pixels of a conventional single-plate solid-state imaging device. It is problem explanatory drawing of the conventional single plate type solid-state image sensor.

Explanation of symbols

100 single-plate solid-state image sensor 101 semiconductor substrate 103 n-type region (photodiode)
108 light shielding film 108a light shielding film opening 111 color filter layer 113 microlens

Claims (8)

  In a method for manufacturing a single-plate solid-state imaging device in which a microlens mounting pixel and a non-microlens mounting pixel are provided adjacent to each other, a first color filter of the microlens mounting pixel and a second color of the microlens nonmounting pixel The incident light of the maximum incident angle that enters the pixel not mounted with the micro lens through the boundary position with the filter is the light blocking film opening on the micro lens mounted pixel side of the light blocking film opening end of the pixel not mounted with the micro lens. A manufacturing method of a single-plate solid-state imaging device, wherein a boundary position between the first color filter and the second color filter is manufactured so as to be in a positional relationship incident on an end.   The method for manufacturing a single-plate solid-state image pickup device according to claim 1, wherein the maximum incident angle is determined by a photographing lens of a digital camera on which the single-plate solid-state image pickup device is mounted. The horizontal distance from the light shielding film opening end on the microlens mounting pixel side to the boundary position is X, and the vertical distance between the upper surface position of the first and second color filters and the upper surface position of the light shielding film opening end. Is Z and the maximum incident angle is θ,
X> Z · tanθ
The method for manufacturing a single-plate solid-state imaging device according to claim 1, wherein the boundary position is provided at a position satisfying the above condition.   4. The method for manufacturing a single-plate solid-state image pickup device according to claim 3, wherein the boundary position is determined by the θ determined by a photographic lens having the largest maximum incident angle among photographic lenses that can be attached to the digital camera. .   5. The method for manufacturing a single-plate solid-state imaging device according to claim 1, wherein the boundary position around the entire circumference of the microlens is manufactured in the positional relationship.   5. The method for manufacturing a single-plate solid-state imaging device according to claim 1, wherein the boundary position around a part of the microlens is manufactured in the positional relationship. 6.   A single-plate solid-state imaging device manufactured by the manufacturing method according to claim 1.   A digital camera comprising the single-plate solid-state imaging device according to claim 7.

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