Photoelectric conversion apparatus and system

A photoelectric conversion apparatus has a photoelectric conversion substrate having a plurality of photoelectric conversion portions and a microlens array arranged above the plurality of photoelectric conversion portions; a light transmissive plate; a first member arranged between the photoelectric conversion substrate and the light transmissive plate; a second member arranged between the first member and the microlens array; and a third member arranged between the first member and the second member. A porosity of the first member<a porosity of the third member<a porosity of the second member is satisfied.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention is related to a photoelectric conversion apparatus and a system.

Description of the Related Art

Photoelectric conversion apparatuses in which a wafer level chip size package (WL-CSP) is used are broadly divided into those having a cavity structure and those having a fill structure. In a photoelectric conversion apparatus having a cavity structure, a photoelectric conversion substrate and a light transmissive plate are bonded to each other by a ring-shaped bonding member, and there is a void between a microlens array of the photoelectric conversion substrate and the light transmissive plate. Regarding a photoelectric conversion apparatus having a fill structure, the entire top surface of the photoelectric conversion substrate and a light transmissive plate are mutually bonded by a bonding member. Although a photoelectric conversion apparatus having the fill structure is superior in structural strength compared to a photoelectric conversion apparatus having the cavity structure, it is inferior in microlens power because the microlens array is covered by the bonding member whose refractive index is higher than that of air. Accordingly, in Japanese Patent Laid-Open No. 2015-159275, a photoelectric conversion substrate and a light transmissive plate are mutually bonded by a bonding member after a top surface of a microlens array is covered by a low-refractive index member whose refractive index is lower than the bonding member.

SUMMARY OF THE INVENTION

In a structure of Japanese Patent Laid-Open No. 2015-159275, since the reflectance at the boundary between the low-refractive index member and the bonding member is large, there is a possibility that a color heterogeneity that is due to the reflection will arise. An aspect of the present invention is to provide a technique for reducing color heterogeneity in a photoelectric conversion apparatus.

According to some embodiments, a photoelectric conversion apparatus comprises: a photoelectric conversion substrate having a plurality of photoelectric conversion portions and a microlens array arranged above the plurality of photoelectric conversion portions; a light transmissive plate; a first member arranged between the photoelectric conversion substrate and the light transmissive plate; a second member arranged between the first member and the microlens array; and a third member arranged between the first member and the second member, wherein a porosity of the first member<a porosity of the third member<a porosity of the second member is satisfied is provided.

DESCRIPTION OF THE EMBODIMENTS

Description is given regarding embodiments of the present invention while referencing attached drawings. The same reference numerals are given to similar elements throughout the various embodiments so duplicate descriptions are omitted. In addition, it is possible to appropriately change and combine each embodiment. In the attached drawings, the scale of each element may be different from that of an actual apparatus in order to simplify comprehension of the described element. Although description is given regarding a front-side illumination photoelectric conversion apparatus below, it is possible to similarly apply the present invention to a back-side illumination photoelectric conversion apparatus. The photoelectric conversion apparatus may also be referred to as a solid-state image capturing apparatus in a case where it is used for forming an image.

Description is given regarding one example of a structure of a photoelectric conversion apparatus100according to some embodiments of the present invention with reference toFIG. 1AtoFIG. 3B.FIG. 1Ais a plan view of the photoelectric conversion apparatus100,FIG. 1Bis a cross-sectional view in the AA line ofFIG. 1A,FIG. 2Ais a cross-sectional view in the BB line ofFIG. 1A, andFIG. 2Bis a cross-sectional view in the CC line ofFIG. 1A. The photoelectric conversion apparatus100is a photoelectric conversion apparatus of a wafer level chip size package. Specifically, the photoelectric conversion apparatus100is obtained by, after forming configuration elements of a plurality of photoelectric conversion apparatuses on a semiconductor wafer, dicing the semiconductor wafer to separate the photoelectric conversion apparatuses as described in a method for manufacturing described later.

The photoelectric conversion apparatus100has a pixel region PX inside of a dashed line DL1, has a peripheral region PE between the dashed line DL1and a dashed line DL2, and has a scribe region SC outside of the dashed line DL2as illustrated inFIG. 1A. The pixel region PX is a region in which a plurality of pixels that convert an incident light to a signal charge are arranged in an array. The peripheral region PE is a region in which a circuit for reading a signal charge accumulated in a pixel or a circuit for driving the pixel is arranged. The scribe region SC is a region which is a target of the dicing in the process for manufacturing of the photoelectric conversion apparatus100, and a circuit used in an operation of the photoelectric conversion apparatus100is not arranged in the scribe region SC. InFIG. 1A, only the dashed lines DL1and DL2which illustrate a boundary of each region, and a low-refractive index member111are illustrated in order to simplify comprehension of the drawing.

Description is given regarding a cross-sectional structure of the photoelectric conversion apparatus100with reference toFIG. 1B. The cross-sectional view ofFIG. 1Bfocuses on a section from a part of the pixel region PX, exceeding a side surface100aof the photoelectric conversion apparatus100, and until the outside of the photoelectric conversion apparatus100. InFIG. 1B, although description is given regarding one side surface100a(left side surface inFIG. 1A) of the photoelectric conversion apparatus100, the photoelectric conversion apparatus100has the same cross-sectional structure at its other outer surfaces.

The photoelectric conversion apparatus100has a semiconductor layer101. The semiconductor layer101is a silicon layer for example. In the pixel region PX, a plurality of photoelectric conversion portions102are arranged in an array in the semiconductor layer101. Each of the plurality of the photoelectric conversion portions102configure a part of a pixel. Description of other elements of a pixel such as a transistor is omitted because they are well known.

The photoelectric conversion apparatus100further has an insulating layer103on top of the semiconductor layer101. The photoelectric conversion apparatus100further has a wiring layer104formed inside of the insulating layer103and a wiring layer105formed on top of the insulating layer103. For this reason, the insulating layer103may be referred to as an interlayer insulation layer. The wiring layers104and105are configured by an electrically conductive member and transfer an electrical signal. Although there are two layers of the wiring layer104in the example ofFIG. 1B, the number of layers of the wiring layer104is not limited to this. The wiring layers104and105are arranged in the pixel region PX and the peripheral region PE. The photoelectric conversion apparatus100further has a ring shaped moisture-proof ring114protruding from the top side of the insulating layer103formed inside of the insulating layer103in the peripheral region PE. The moisture-proof ring114entirely surrounds the periphery of the wiring layers104and105. The moisture-proof ring114may be formed by the same material as the wiring layer104.

The photoelectric conversion apparatus100further has a passivation film106on top of the insulating layer103and the wiring layer105. The passivation film106is arranged across the entirety of the photoelectric conversion apparatus100. Specifically, an edge of the passivation film106extends until the side surface100aof the photoelectric conversion apparatus100. The top surface of the passivation film106has an unevenness in accordance with a pattern of the wiring layer105in the example ofFIG. 1B. Instead of this, the top surface of the passivation film106may be flat compared to the unevenness in accordance with the pattern of the wiring layer105.

The photoelectric conversion apparatus100further has a planarizing layer107on top of the passivation film106. The planarizing layer107is a resin layer formed by a resin for example. The top surface of the planarizing layer107is flat compared to the bottom surface. Below, not limited to the planarizing layer107, planarizing layer means a layer whose top surface is flat compared to the bottom surface. The planarizing layer107is arranged across the entirety of the pixel region PX and the peripheral region PE, and is not arranged in the scribe region SC. In the example ofFIG. 1B, the edge of the planarizing layer107extends until the boundary (dashed line DL2) of the peripheral region PE and the scribe region SC. Alternatively, the edge of the planarizing layer107may extend until part way through the peripheral region PE.

The photoelectric conversion apparatus100further has a color filter layer108on top of the planarizing layer107. The color filter layer108is formed by a resin for example. A plurality of color filters corresponding to the plurality of pixels are formed in the color filter layer108. The plurality of color filters are arranged in a Bayer arrangement for example. The top surface of the color filter layer108has an unevenness because the height differs for each color filter. The color filter layer108is arranged across the entirety of the pixel region PX and to part way through the peripheral region PE, and is not arranged in the scribe region SC. Specifically, the edge of the color filter layer108extends until part way through the peripheral region PE.

The photoelectric conversion apparatus100further has a planarizing layer109on top of the planarizing layer107and the color filter layer108. The planarizing layer109is a resin layer formed by a resin for example. The portion on top of the color filter layer108in the top surface of the planarizing layer109is flat compared to the unevenness according to the color filter layer108, and the portion outside of the color filter layer108in the top surface of the planarizing layer109is also flat compared to the unevenness according to the color filter layer108. The portion of the top surface of the planarizing layer109on top of the color filter layer108and the portion that is outside are at different heights from the semiconductor layer101. The planarizing layer109is arranged across the entirety of the pixel region PX and the peripheral region PE, and is not arranged in the scribe region SC. In the example ofFIG. 1B, the edge of the planarizing layer109extends until the boundary (dashed line DL2) of the peripheral region PE and the scribe region SC. Alternatively, the edge of the planarizing layer109may extend until part way through of the peripheral region PE. In the example ofFIG. 1B, the edge of the planarizing layer107and the edge of the planarizing layer109extend until the same position. Configuration may be taken such that the photoelectric conversion apparatus100does not have the color filter layer108or the planarizing layer109in a case where an identification of colors is not necessary in the photoelectric conversion apparatus100.

The photoelectric conversion apparatus100further has a microlens array110on top of the planarizing layer109. The microlens array110is formed by a resin for example. The microlens array110may be formed by an organic material and may be formed by an inorganic material. The microlens array110is a group of a plurality of microlenses arranged in an array. The plurality of microlenses are arranged corresponding to the plurality of photoelectric conversion portions102and the top surface of each microlens is a convex curve. The microlens array110is arranged across the entirety of the pixel region PX and to part way through the peripheral region PE, and is not arranged in the scribe region SC. The microlens array110may be formed by the same material as the planarizing layer109or may be formed by a different material. The edge of the microlens array110is positioned further inside (a side farther from the side surface100a) than the edge of the color filter layer108.

The photoelectric conversion apparatus100further has the low-refractive index member111on top of the microlens array110, and has a medium-refractive index member118on top of the low-refractive index member111. The low-refractive index member111and the medium-refractive index member118are arranged across the entirety of the pixel region PX and part way through the peripheral region PE, and are not arranged in the scribe region SC. The edges of the low-refractive index member111and the medium-refractive index member118are positioned further inside (a side farther from the side surface100a) than the edge of the microlens array110. In this way, the low-refractive index member111and the medium-refractive index member118cover a part of the microlens array110. The side surface of the low-refractive index member111and the side surface of the medium-refractive index member118are flush with each other. On top of the plurality of photoelectric conversion portions102, both the top surface of the low-refractive index member111and the top surface of the medium-refractive index member118are flat compared to the unevenness according to the microlenses110a. Also, on top of the plurality of photoelectric conversion portions102, the low-refractive index member111contacts the microlens array110and the medium-refractive index member118contacts the low-refractive index member111. Above the apex of the microlenses included in the microlens array110, a thickness t2of the medium-refractive index member118is smaller than a thickness t1of the low-refractive index member111. For example, the thickness t1of the portion on top of the apex of the microlenses in the low-refractive index member111may be 2.0 μm or more, and may be 5.0 μm or less, and may be 2.0 μm or less. The thickness t2of the medium-refractive index member118may be constant across the entire region, and may be 50 nm or more, for example, and 150 nm or less, for example, and may be 97 nm, for example.

A structure formed from the above described semiconductor layer101to the microlens array110is referred to as a photoelectric conversion substrate. The photoelectric conversion apparatus100further has the low-refractive index member111, the medium-refractive index member118, a bonding member112, and a light transmissive plate113.

The light transmissive plate113is a plate-shaped member through which light passes and is formed by glass, for example. The light transmissive plate113may have a strength such that it protects the photoelectric conversion substrate. The top surface113aof the light transmissive plate113is a light-receiving surface that receives light incident on the photoelectric conversion apparatus100. Light that entered from the top surface113ais converted into an electrical signal by the photoelectric conversion substrate.

The bonding member112is arranged between the photoelectric conversion substrate and the light transmissive plate113, and mutually bonds the photoelectric conversion substrate and the light transmissive plate113. The low-refractive index member111is arranged between the bonding member112and the microlens array110. The medium-refractive index member118is arranged between the bonding member112and the low-refractive index member111. The bonding member112is formed by curing an adhesive agent as described in the method for manufacturing described later. For this reason, the bonding member112is a member configured by a single material. An organic material which becomes transparent after being cured, an acrylic epoxy for example, may be used as the adhesive agent material.

The side surface of the bonding member112configures a part of the side surface100aof the photoelectric conversion apparatus100. The top surface112aof the bonding member112(that it, the surface on the side of the light transmissive plate113) contacts and is bonded with the light transmissive plate113. Accordingly, the top surface112aof the bonding member112can be referred to as a contact surface or a bonding surface. The top surface112aextends until the side surface100aof the photoelectric conversion apparatus100and the entire surface of the top surface112ais bonded to the light transmissive plate113. The top surface112ais flat because the light transmissive plate113is a plate-shaped member.

The bottom surface112bof the bonding member112(that is, the surface of the side of the photoelectric conversion substrate) contacts and is bonded with the photoelectric conversion substrate and the low-refractive index member111. Accordingly, the bottom surface112bof the bonding member112can be referred to as a contact surface or a bonding surface. The top surface112aand the bottom surface112bare at opposite sides to each other. The bottom surface112bextends until the side surface100aof the photoelectric conversion apparatus100and is bonded to the photoelectric conversion substrate in the proximity of the outer circumference of the bottom surface112b. Specifically, the bottom surface112bcontacts and is bonded with the top surface and the side surface of the low-refractive index member111and the portion of the top surface of the microlens array110not covered by the low-refractive index member111. The bottom surface112bfurther contacts and is bonded with the portion of the top surface of the planarizing layer109not covered by the microlens array110, the edge of the planarizing layer107, and a portion of the passivation film106not covered by the planarizing layer107.

By the respective refractive indexes of the low-refractive index member111, the medium-refractive index member118, and the bonding member112satisfying the following relationship, an optical characteristic as typified by color heterogeneity can be improved.
The refractive index of the bonding member 112>the refractive index of the medium-refractive index member 118>the refractive index of the low-refractive index member 111  (Equation 1)

Configuration may be such that the respective refractive indexes of the microlens array110, the low-refractive index member111, the medium-refractive index member118, and the bonding member112satisfy the following relationship:
The refractive index of the microlens array 110>the refractive index of the bonding member 112>the refractive index of the medium-refractive index member 118>the refractive index of the low-refractive index member 111  (Equation 1a)

For example, in relation to light of a wavelength of 550 nm, the refractive index of the microlens array110is 1.87, the refractive index of the bonding member112is 1.55, the refractive index of the medium-refractive index member118is 1.33, and the refractive index of the low-refractive index member111is 1.22. Furthermore, the refractive index of the low-refractive index member111may be 1.15 or more and may be 1.30 or less. The refractive index of the microlens array110may be 1.50 or more and may be 1.90 or less. If the microlens array110is formed by a single member, the refractive index of the member is the refractive index of the microlens array110. In a case where the microlens array110has a stacked structure and each layer is formed by a different material, the refractive index of the layer closest to the low-refractive index member111may be made to be the refractive index of the microlens array110.

Configuration may be such that the respective refractive indexes of the microlens array110, the low-refractive index member111, the medium-refractive index member118, and the bonding member112satisfy the following relationship:
The refractive index of the bonding member 112>the refractive index of the microlens array 110>the refractive index of the medium-refractive index member 118>the refractive index of the low-refractive index member 111  (Equation 1b)

Typically, the porosity and the refractive index of a member whose principal component is the same material have a negative correlation. The porosity may be defined as a ratio of a volume that a portion of air occupies out of the whole. It is also possible that the porosity be measured as a ratio of an area that a portion of a void occupies out of the whole in a cross-sectional view. In one example of a specific measurement method for a porosity, an electron microscope photograph of a cross section of a measurement target is obtained, binarization processing for voids and solid portions is performed by image processing, and the area of the voids corresponding to a unit area is made to be the porosity. Accordingly, by the porosities of each of the microlens array110, the low-refractive index member111, the medium-refractive index member118, and the bonding member112satisfying the following relationship, the optical characteristic and the mechanical characteristic can be improved.
The porosity of the bonding member 112<the porosity of the medium-refractive index member 118<the porosity of the low-refractive index member 111   (Equation 2)

The photoelectric conversion apparatus100may satisfy at least one of Equation 1 and Equation 2. The porosity of the low-refractive index member111may be 40% or more and may be 60% or less, for example. The porosity of the medium-refractive index member118may be 20% or more and may be 40% or less, for example. The porosity of the bonding member112may be 20% or more and may be 30% or less, for example. The porosity of the microlens array110may be 0% or more and may be 20% or less, for example. The porosity of the microlens array110may be 0%.

Configuration may be such that the porosities of the microlens array110, the medium-refractive index member118, and the bonding member112satisfy the following relationship:
The porosity of the microlens array 110≠the porosity of the medium-refractive index member 118   (Equation 2a)
The porosity of the microlens array 110<the porosity of the bonding member 112  (Equation 2b)

Furthermore, the low-refractive index member111and the medium-refractive index member118may satisfy the following relationship:
The film density of the medium-refractive index member 118>the film density of the low-refractive index member 111  (Equation 3)

For example, the film density of the low-refractive index member111may be 0.1 g/cm3or more and may be 1.0 g/cm3or less. The film density of the medium-refractive index member118may be 1.0 g/cm3or more and may be 10 g/cm3or less.

Next, description is given regarding another cross-sectional structure of the photoelectric conversion apparatus100with reference toFIG. 2A.FIG. 2Ais a cross section at a different position thanFIG. 1B, and illustrates a cross section through an electrode116. The cross-sectional view ofFIG. 2Afocuses on a section from a part of the pixel region PX, exceeding a side surface100aof the photoelectric conversion apparatus100, and until the outside of the photoelectric conversion apparatus100. InFIG. 2A, although description is given regarding one side surface100a(left side surface inFIG. 1A) of the photoelectric conversion apparatus100, the photoelectric conversion apparatus100has the same cross-sectional structure at its other side surfaces.

A through hole115is formed in the semiconductor layer101and the insulating layer103as illustrated inFIG. 2A. One end of the through hole115reaches a portion105aof the wiring layer105. The photoelectric conversion apparatus100further has the electrode116which passes through the through hole115. A part of the electrode116contacts and is bonded with the portion105aof the wiring layer105, and another portion116aof the electrode116extends parallel to the bottom surface of the semiconductor layer101(specifically, the surface on the side opposite to the light transmissive plate113). A solder bump117for soldering the photoelectric conversion apparatus100to a mounting board is provided on the portion116aof the electrode116. The portion116aof the electrode116and the low-refractive index member111and the medium-refractive index member118are arranged to have a space W between them in the plan view in relation to the top surface113aof the light transmissive plate113. Due to such an arrangement, it is possible to reduce a force on the low-refractive index member111and the medium-refractive index member118when soldering the photoelectric conversion apparatus100to the mounting board. This arrangement is advantageous in a case where the structural strength of the low-refractive index member111and the medium-refractive index member118is low.

Next, description is given regarding another cross-sectional structure of the photoelectric conversion apparatus100with reference toFIG. 2B.FIG. 2Bis a cross section at a different position thanFIG. 1B, and illustrates a cross section through a pad for inspection. The cross-sectional view ofFIG. 2Bfocuses on a section from a part of the pixel region PX, exceeding a side surface100aof the photoelectric conversion apparatus100, and until the outside of the photoelectric conversion apparatus100. InFIG. 2B, although description is given regarding one side surface100a(left side surface inFIG. 1A) of the photoelectric conversion apparatus100, the photoelectric conversion apparatus100may have the same cross-sectional structure at another side surface.

The passivation film106, the planarizing layer107, and the planarizing layer109are removed from the top of the portion105bof the wiring layer105. The portion105bof the wiring layer105is positioned at the peripheral region PE. The portion105bof the wiring layer105functions as a pad for inspecting the photoelectric conversion substrate during manufacturing of the photoelectric conversion apparatus100. The bottom surface112bof the bonding member112also contacts and is bonded with the portion105bof the wiring layer105.

Next, an example of a material of the low-refractive index member111is described with reference toFIGS. 3A and 3B. The medium-refractive index member118is formed by a similar material to the low-refractive index member111explained below. In the example illustrated inFIG. 3A, the low-refractive index member111is formed by a plurality of chain fillers301and a binder302(bonding agent) which bonds the plurality of chain fillers301. Each of the plurality of chain fillers301may include a solid silica particle for example. The binder is a polysiloxane or an acrylic resin for example. Each chain filler301is enveloped in the binder302. A structure in which the chains of the plurality of chain fillers301are sterically bonded is formed by bonding the plurality of chain fillers301to each other by the binder302. For this reason, the low-refractive index member111has voids303between the plurality of the chain fillers301.

In the example illustrated inFIG. 3B, the low-refractive index member111is formed by a plurality of granular fillers304and a binder305(bonding agent) which bonds the plurality of granular fillers304. Each of the plurality of granular fillers304has a hollow structure including a void306inside and may include a hollow silica particle for example. The binder is polysiloxane or an acrylic resin for example.

Furthermore, the low-refractive index member111and the medium-refractive index member118may both have the same structure, or may have different structures. For example, the low-refractive index member111and the medium-refractive index member118may both have the structure ofFIG. 3AorFIG. 3B. Instead of that, configuration may be taken such that the low-refractive index member111has the structure of eitherFIG. 3AorFIG. 3B, and the medium-refractive index member118has the structure of the other of FIG.3A orFIG. 3B. The respective porosities of the low-refractive index member111and the medium-refractive index member118can be set by adjusting the ratios that the voids303and306occupy. Even if the material of either of the examples ofFIGS. 3A and 3Bare used, it is possible to make the porosities larger than that of the microlens array110because the low-refractive index member111and the medium-refractive index member118are structures including the voids303and306.

As described above, in the photoelectric conversion apparatus100, because at least one of Equation 1 and Equation 2 is satisfied, it is possible to have the following effects. Firstly, it is possible to reduce first-order reflection in the top surface of the low-refractive index member111and second-order reflection in the top surface of the microlens array110. For this reason, a color heterogeneity in the photoelectric conversion apparatus100is reduced. Also, because it is possible to make the low-refractive index member111into a thin film, it is possible to suppress the occurrence of cracks in the photoelectric conversion apparatus100. Furthermore, by arranging the medium-refractive index member118between the low-refractive index member111and the bonding member112, stress between the low-refractive index member111and the bonding member112is alleviated, and as a result it is possible to suppress cracks and film peeling in the photoelectric conversion apparatus100. Furthermore, the bottom surface112bof the bonding member112contacts a portion of the top surface of the microlens array110and a portion of the top surface of the planarizing layer109and bonds to them, and thereby it is possible to reduce the ratio of the bonding area with the medium-refractive index member118where the bonding strength is relatively weak. Furthermore, a part of the photoelectric conversion substrate (the microlens array110for example) is formed by an organic material, and an improvement in adhesion due to a polar group such as an OH group or a COOH group in a case where the bottom surface112bof the bonding member112contacts and is bonded with a portion of the organic material is achieved. Peeling or cracking due to moisture absorption, shock, and temperature change at a time of using the photoelectric conversion apparatus100can be suppressed by improving the bond between the bonding member112and the photoelectric conversion substrate.

Next, a description is given regarding a method for manufacturing of the photoelectric conversion apparatus100with reference toFIG. 4AtoFIG. 6B. Firstly, the semiconductor layer101as illustrated inFIGS. 4A and 4Bis prepared.FIG. 4Aillustrates a plan view of the semiconductor layer101, andFIG. 4Billustrates a cross-sectional view in a DD line. The DD line ofFIG. 4Ais at a position corresponding to the CC line ofFIG. 1A. A plurality of pairs of the pixel region PX and the peripheral region PE in the periphery thereof are arranged in 3 rows and 3 columns spaced apart on the semiconductor layer101as illustrated inFIG. 4A. An impurity region (the photoelectric conversion portion102for example) for configuring one photoelectric conversion apparatus100is formed for each pair of the pixel region PX and the peripheral region PE. A region outside of the peripheral region PE is the scribe region SC. The cross-sectional view ofFIG. 4Bfocuses on a section from a part of one pixel region PX, exceeding the scribe region SC, and to a part of the peripheral region PE for forming another photoelectric conversion apparatus100.

Next, the insulating layer103, the wiring layer104, the wiring layer105, the moisture-proof ring114, and the passivation film106are formed on top of the semiconductor layer101as illustrated inFIG. 4C. A detailed description is omitted because a conventional technique is used in this step. Next, an opening is formed in the passivation film106so that the portion105bof the wiring layer105is exposed as illustrated inFIG. 5A. As described above, the portion105bof the wiring layer105is used as a pad for inspection.

Next, the planarizing layer107, the color filter layer108, the planarizing layer109, and the microlens array110are formed in this order on top of the passivation film106as illustrated inFIG. 5B. For example, the planarizing layer107and the planarizing layer109are respectively formed by baking after spin-coating with a resin material. The color filter layer108is formed by performing a photolithography step after applying an organic resin. The microlens array110is formed by performing a photolithography step or an etchback step after depositing an organic material or an inorganic material.

Next, portions of the planarizing layer107and the planarizing layer109covering the scribe region SC and the portion105bof the wiring layer105are removed as illustrated inFIG. 6A. In this step, the portions of the planarizing layer107and the planarizing layer109covering between the scribe region SC and the portion105bof the wiring layer105may also be removed as illustrated inFIG. 6A. After that, the low-refractive index member111and the medium-refractive index member118are formed in this order. For example, the low-refractive index member111and the medium-refractive index member118is formed by a dry etching, a wet etching, a printing method, or the like. The low-refractive index member111and the medium-refractive index member118may be formed by a photolithography step in a case where the low-refractive index member111is formed by a photosensitive material. The photoelectric conversion substrate is formed by the foregoing steps.

Next, the photoelectric conversion substrate formed by the foregoing steps and the light transmissive plate113which is prepared separately, are bonded together by an adhesive agent112′ and the adhesive agent112′ is caused to be cured after this as illustrated inFIG. 6B. The cured adhesive agent112′ is the bonding member112. After this, in a process that is not shown graphically, the bottom surface of the semiconductor layer101is thinned by polishing the semiconductor layer101. Then, the through hole115penetrating the semiconductor layer101and the insulating layer103is formed and the electrode116which passes through this through hole115is formed. Furthermore, a plurality (nine in this example) of photoelectric conversion apparatuses100are obtained by dicing the scribe region SC.

Next, description is given regarding various variations of the photoelectric conversion apparatus100with reference toFIG. 7AtoFIG. 9B. A configuration illustrated in a variation, may be applied to only some of the side surfaces of the photoelectric conversion apparatus100and may be applied to all of the side surface. Also, the applied variation may be the same or may be different for each side surface of the photoelectric conversion apparatus100. In the description below, description regarding the same configuration as in the photoelectric conversion apparatus100is omitted, and description regarding points of difference is given. Each drawing described below corresponds to the cross-sectional view of the photoelectric conversion apparatus100illustrated inFIG. 1B. There are also the same points of difference regarding the cross-sectional views illustrated inFIG. 2AandFIG. 2B.

In a photoelectric conversion apparatus700illustrated inFIG. 7A, the position of the edges of the low-refractive index member111and the medium-refractive index member118is different to in the photoelectric conversion apparatus100. The low-refractive index member111and the medium-refractive index member118cover the entirety of the microlens array110. The edges of the low-refractive index member111and the medium-refractive index member118are positioned between the edge of the microlens array110and the edge of the color filter layer108in the plan view for the top surface113aof the light transmissive plate113.

In a photoelectric conversion apparatus750illustrated inFIG. 7B, the position of the edges of the low-refractive index member111and the medium-refractive index member118is different to in the photoelectric conversion apparatus100. The low-refractive index member111and the medium-refractive index member118cover the entirety of the microlens array110. The edges of the low-refractive index member111and the medium-refractive index member118are positioned between the edge of the planarizing layer109and the edge of the color filter layer108in the plan view for the top surface113aof the light transmissive plate113.

In a photoelectric conversion apparatus800illustrated inFIG. 8A, there is a difference from the photoelectric conversion apparatus100in that there additionally is an intermediate film801which covers the entirety of the top surface of the microlens array110. The intermediate film801is arranged between at least a part of the microlens array110and the low-refractive index member111. The intermediate film801may be formed by a material that satisfies at least one of Equation 4 and Equation 5 below:
The refractive index of the microlens array 110>the refractive index of the intermediate film 801>the refractive index of the low-refractive index member 111  (Equation 4)
The porosity of the intermediate film 801<the porosity of the low-refractive index member 111   (Equation 5)

Furthermore, the intermediate film801may be formed by a material that satisfies at least one of Equation 6 and Equation 7 below:
The refractive index of the microlens array 110>the refractive index of the intermediate film 801>the refractive index of the medium-refractive index member 118  (Equation 6)
The porosity of the intermediate film 801<the porosity of the medium-refractive index member 118  (Equation 7)

For example, if the microlens array110is formed by silicon nitride (in relation to light whose wavelength is 550 nm, the refractive index is 1.87), the intermediate film801may be formed by silicon oxide (in relation to light whose wavelength is 550 nm, the refractive index is 1.47). The intermediate film801has a portion which extends from between the microlens array110and the low-refractive index member111to further to the outside than the edge of the low-refractive index member111. This extending portion is positioned between the photoelectric conversion substrate and the bonding member112. The intermediate film801extends until the edge of the planarizing layer109in one example, and the edge of the extending portion is separated from the side surface of the photoelectric conversion apparatus800. The top surface of the portion covering the microlens array110in the intermediate film801is a curved surface shape similar to the top surface of the microlens array110. Specifically, the top surface of the intermediate film801has a lens shape. That is, the top surface of the intermediate film801has an unevenness according to the unevenness of the lens array110. For this reason, a combination of the microlens array110and a portion of the intermediate film801on the top of the microlens array110may be considered to be configuring a microlens array. The intermediate film801functions as a member that has various effects such as preventing reflection, improving adhesion, preventing contamination, and mitigating stress. The intermediate film801is an inorganic material film, for example.

In a photoelectric conversion apparatus850illustrated inFIG. 8B, there is a difference from the photoelectric conversion apparatus100in that there additionally is an intermediate film851which covers a part of the top surface of the microlens array110. A material of the intermediate film851may be the same as the material of the intermediate film801. The edge of the intermediate film851aligns with the edge of the low-refractive index member111. For this reason, the top surface of the intermediate film851does not include a portion that contacts with the bottom surface112bof the bonding member112because it is covered by the low-refractive index member111.

In a photoelectric conversion apparatus900illustrated inFIG. 9A, there is a difference from the photoelectric conversion apparatus100in that the insulating layer103has a step at the scribe region SC. The bottom surface112bof the bonding member112also contacts and is bonded with this step. The bonding member112does not contact with the semiconductor layer101because a part of the insulating layer103remains on a portion of the bottom of this step.

In a photoelectric conversion apparatus950illustrated inFIG. 9B, there is a difference from the photoelectric conversion apparatus100in that the planarizing layer107, the color filter layer108, the planarizing layer109, and the microlens array110each extend until the side surface100aof the photoelectric conversion apparatus100. A portion of the microlens array110is not covered by the low-refractive index member111. For this reason, the bottom surface112bof the bonding member112contacts and is bonded with this portion of the microlens array110.

In a photoelectric conversion apparatus1000illustrated inFIG. 10A, the edge of the medium-refractive index member118is different from that in the photoelectric conversion apparatus100in that it extends until the edge of the planarizing layer109. As a result of this, the medium-refractive index member118covers the side surface of the low-refractive index member111, a part of the microlens array110, and a part of the planarizing layer109, and contacts these. Instead of this, the edge of the medium-refractive index member118may be positioned somewhere between the edge of the low-refractive index member111and the edge of the planarizing layer109.

A photoelectric conversion apparatus1050illustrated inFIG. 10Bdiffers from the photoelectric conversion apparatus100in that it further comprises a mask layer119between the medium-refractive index member118and the bonding member112. The mask layer119is used in etching to form the low-refractive index member111and the medium-refractive index member118in the foregoingFIG. 6A. After etching, the photoelectric conversion substrate and the light transmissive plate113are bonded by an adhesive agent112′ without removing the mask layer119.

A photoelectric conversion apparatus1100illustrated inFIG. 11is different from the photoelectric conversion apparatus100in that it further comprises an intermediate film1101. The intermediate film1101is arranged between the planarizing layer109and the microlens array110. Specifically, the intermediate film1101is arranged between the plurality of photoelectric conversion portions102and the microlens array110. On top of the plurality of photoelectric conversion portions102, the microlens array110contacts the intermediate film1101and the intermediate film1101contacts the planarizing layer109. A material of the intermediate film1101may be the same as the material of the intermediate film801. The edge of the intermediate film1101extends to the edge of the planarizing layer109. Instead of this, the edge of the intermediate film1101may be positioned somewhere between the edge of the low-refractive index member111and the edge of the microlens array110. Furthermore, instead of providing the intermediate film1101, configuration may be taken so that the planarizing layer109functions as a member having various effects such as reflection prevention, adhesion improvement, contamination prevention, and stress alleviation similar to the intermediate film1101.

With reference toFIGS. 12A-12D, description is given regarding an example of the microlens array110of the photoelectric conversion apparatus according to various embodiments described above.FIG. 12Ais a plan view focusing on a part of the microlens array110. The microlens array110is configured by a plurality of microlenses110acorresponding to a plurality of photoelectric conversion portions102. The plurality of microlenses are arranged in an array similarly to the plurality of photoelectric conversion portions102. The microlens array110has a region110bthat does not contribute to focusing between two microlenses110athat are arranged in a diagonal direction in the array. The region110bthat does not contribute to focusing may be a portion that is flat compared to the unevenness according to the microlens110aand that is formed by the same material as the microlens110a. Also, the region110bthat does not contribute to focusing may be a portion in which another member (such as the low-refractive index member111or the intermediate film801as described later) is arranged.FIGS. 12A-12Ddescribe the case of the latter.

Each ofFIG. 12B-FIG. 12Dare cross-sectional views of portions including the microlens array110in the photoelectric conversion apparatus according to the various embodiments described above. The left side of each view is a DD line cross-sectional view ofFIG. 12A, and the right side is an EE line cross-sectional view ofFIG. 12A.FIG. 12Billustrates a cross-sectional view of the photoelectric conversion apparatus in which, as with the photoelectric conversion apparatus100, the low-refractive index member111contacts the microlens array110, and the microlens array110contacts the planarizing layer109. In this example, in the region110bthat does not contribute to focusing, the low-refractive index member111contacts the planarizing layer109.FIG. 12Cillustrates a cross-sectional view of the photoelectric conversion apparatus in which the intermediate film801is arranged between the low-refractive index member111and the microlens array110, as in the photoelectric conversion apparatus800. In this example, in the region110bthat does not contribute to focusing, the low-refractive index member111contacts the intermediate film801, and the intermediate film801contacts the planarizing layer109.FIG. 12Dillustrates a cross-sectional view of the photoelectric conversion apparatus in which the intermediate film1101is arranged between the planarizing layer109and the microlens array110, as in the photoelectric conversion apparatus1100. In this example, in the region110bthat does not contribute to focusing, the low-refractive index member111contacts the intermediate film801. In the configurations ofFIG. 12CandFIG. 12Dout of the configurations ofFIG. 12B-FIG. 12D, the intermediate film801or the intermediate film1101are arranged between the low-refractive index member111and the planarizing layer109, and therefore it is possible to reduce the first-order reflection on the bottom surface of the low-refractive index member111.

Hereinafter, a description is exemplarily given of a camera which is an example of a system in which this photoelectric conversion apparatus is embedded as an application of the photoelectric conversion apparatus according to each of the foregoing embodiments. Not only apparatuses whose main function is capturing but also systems having a supplemental capturing function (such as a personal computer, a mobile terminal, and an automobile for example) are included in the concept of camera. Also, the camera may be a modular part such as a camera head for example. The camera includes the photoelectric conversion apparatus according to the present invention as exemplified in the foregoing embodiments and a signal processor for processing a signal outputted from this photoelectric conversion apparatus. This signal processor may include a processor for processing digital data based on a signal obtained by the photoelectric conversion apparatus for example. An A/D converter for generating this digital data may be arranged in a semiconductor layer of the photoelectric conversion apparatus and may be arranged in a separate semiconductor layer. Also, it is possible to separately use a support substrate arranged on a side opposite to the light transmissive plate113with respect to the semiconductor layer101in a case where the semiconductor layer101is thinned to approximately 1 μm to 500 μm. On this support substrate, an A/D converter, a processor, a memory, or the like may be arranged.

This application claims the benefit of Japanese Patent Application No. 2016-197546, filed Oct. 5, 2016, which is hereby incorporated by reference herein in its entirety.