Patent Grant
10854664
This application is a U.S. National Phase of International Patent Application No. PCT/JP2017/030856 filed on Aug. 29, 2017, which claims priority benefit of Japanese Patent Application No. JP 2016-177334 filed in the Japan Patent Office on Sep. 12, 2016. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety.
The present disclosure relates to a solid-state image pickup device and a method for manufacturing the same, and an electronic apparatus, and in particular, to a solid-state image pickup device suitable for use in a compound eye optical system and a method for manufacturing the same, and an electronic apparatus, for example.
In related art, for example, as an image sensor used in the compound eye optical system, a configuration in which a light shielding body is provided between a microlens and a light receiving element has been known (see, for example, Patent Document 1).
An image sensor 10 is configured by stacking a light receiving element layer 11, a transparent insulating layer 13, a light shielding body 14, and a microlens array 17. The light receiving element layer 11 includes a large number of light receiving elements 12 disposed vertically and horizontally. The light shielding body 14 includes a light transmitting portion 16 in which a photopolymerizable resin through which light is transmitted is formed in a columnar shape by lithography, and a light shielding wall 15 formed by filling a black pigment resin between the light transmitting portions 16. A microlens array 17 is formed such that one microlens is disposed with respect to each opening portion (the light transmitting portion 16 surrounded by the light shielding wall 15) of the light shielding body 14, and a cover glass or the like is stacked on the microlens for planarization.
According to the image sensor 10, the incident light condensed by the microlens array 17 can be made incident on the light receiving element 12 just below the light transmitting portion 16, via the light transmitting portion 16 surrounded by the light shielding wall 15. In addition, since the light shielding body 14 is disposed, it is possible to prevent the condensed incident light from leaking to the light receiving element of an adjacent section. Furthermore, since the light transmitting portion 16 is disposed between the light shielding walls 15 forming the light shielding body 14, it is possible to prevent dew condensation from occurring on the side surface of the light shielding wall 15 due to environmental changes such as a temperature change.
As described above, although the leakage of incident light is suppressed by disposing the light shielding body 14 in the image sensor 10, the image sensor 10 is still susceptible to the influence of color mixture and stray light.
Further, the positions of the light shielding wall 15 and the light transmitting portion 16 constituting the light shielding body 14 of the image sensor 10 are determined by forming the photopolymerizable resin in a column shape by lithography. However, because the thickness of the photopolymerizable resin forming the light transmitting portion 16 is relatively thick, it is difficult to increase the formation accuracy of the light transmitting portion 16, and it is difficult to form the light transmitting portion 16 in an ideal rectangular shape.
This may cause problems in the case of connecting images obtained from the light receiving element 12 just below each microlens. This problem will be described with reference to
The present disclosure has been made in view of such circumstances, and makes it possible to suppress color mixture, stray light, degradation of contour resolution, and the like which may occur in the solid-state image pickup device having a structure in which the light shielding body is disposed on the light receiving element layer.
A solid-state image pickup device of a first aspect of the present disclosure includes: a light shielding body having light shielding walls and a light transmitting portion formed in an opening portion between the light shielding walls; a first light shielding layer which is formed on an incident surface side of light of the light shielding body, and has an opening portion narrower than the opening portion of the light shielding body for each of the opening portions of the light shielding body; a microlens provided on the incident surface side of light of the light shielding body and for each of the opening portions of the first light shielding layer; a light receiving element layer in which a large number of light receiving elements which perform photoelectric conversion in accordance with incident light condensed by the microlens and input via the light transmitting portion of the light shielding body are arranged; and a second light shielding layer which is formed on the light receiving element layer side of the light shielding body, and has an opening portion narrower than the opening portion of the light shielding body and wider than the first light shielding layer for each of the opening portions of the light shielding body.
A method for manufacturing a solid-state image pickup device of a second aspect of the present disclosure includes: forming a first light shielding layer having an opening portion narrower than an opening portion of a light shielding body for each of the opening portions of the light shielding body, on an incident surface side of light of the light shielding body having light shielding walls and a light transmitting portion formed in an opening portion between the light shielding walls; forming a microlens on the incident surface side of light of the light shielding body and for each of the opening portions of the first light shielding layer; and forming a second light shielding layer narrower than the opening portion of the light shielding body and wider than the first light shielding layer for each of the opening portions of the light shielding body, on the light receiving element layer side of the light shielding body.
An electronic apparatus of a third aspect of the present disclosure includes a solid-state image pickup device, the solid-state image pickup device including: a light shielding body having light shielding walls and a light transmitting portion formed in an opening portion between the light shielding walls; a first light shielding layer which is formed on an incident surface side of light of the light shielding body and has an opening portion narrower than the opening portion of the light shielding body for each of the opening portions of the light shielding body; a microlens provided on the incident surface side of light of the light shielding body and for each of the opening portions of the first light shielding layer; a light receiving element layer in which a large number of light receiving elements which perform photoelectric conversion in accordance with incident light condensed by the microlens and input via the light transmitting portion of the light shielding body are arranged; and a second light shielding layer which is formed on the light receiving element layer side of the light shielding body, and has an opening portion narrower than the opening portion of the light shielding body and wider than the first light shielding layer for each of the opening portions of the light shielding body.
In the first to third aspects of the present disclosure, on an incident surface side of light of a light shielding body having light shielding walls and a light transmitting portion formed in an opening portion between the light shielding walls, a first light shielding layer having an opening portion narrower than the opening portion of the light shielding body for each of the opening portions of the light shielding body is formed, a microlens is formed on the incident surface side of light of the light shielding body and for each of the opening portions of the first light shielding layer, and, on the light receiving element layer side of the light shielding body, a second light shielding layer having an opening portion narrower than the opening portion of the light shielding body and wider than the first light shielding layer for each of the opening portions of the light shielding body is formed.
According to the first to third aspects of the present disclosure, it is possible to suppress problems such as color mixture, stray light, and degradation of contour resolution which may occur in the solid-state image pickup device having a structure in which the light shielding body is disposed on the light receiving element layer.
Further, the effects described herein are not necessarily limited, and may be any of the effects described in the present disclosure.
Hereinafter, best modes (hereinafter referred to as embodiments) for implementing the present disclosure will be described in detail with reference to the drawings.
An image sensor 20 is, for example, a solid-state image pickup device used for a compound eye optical system, and is formed by joining a light receiving element layer 21 and a light shielding body 23 separately generated with a thin film joining resin layer 22. By joining the light receiving element layer 21 and the light shielding body 23 with no gap by the thin film joining resin layer 22, it is possible to prevent a dew condensation which may occur in the gap in the past. Therefore, deterioration of the obtained image can be suppressed.
The light receiving element layer 21 includes a large number of light receiving elements arranged vertically and horizontally. The thin film joining resin layer 22 includes a transparent material and is arranged to join the light receiving element layer 21 and the light shielding body 23 with no gap.
The light shielding body 23 includes a light shielding wall 26 including a light shielding material such as Si, and a light transmitting portion 25 including a transparent material such as glass or resin. The light shielding wall 26 is formed by opening penetration holes in the light shielding material by processing such as lithography and dry etching. The light transmitting portion 25 is formed by filling a space between the light shielding walls 26 (that is, penetration holes) with a transparent material.
That is, the opening portion surrounded by the light shielding wall 26 serves as the light transmitting portion 25, and the light shielding body 23 is formed to transmit the light incident from an upper side (an incident surface side of light) to a lower side (a light receiving element side).
A lower side light shielding layer 24 is formed on the lower side of the light shielding body 23. The lower side light shielding layer 24 includes a light shielding material such as a black color filter (BLK CF), Ti, and W, and has a rectangular opening portion narrower than each opening portion (the light transmitting portion 25 surrounded by the light shielding wall 26) of the light shielding body 23.
On the other hand, an upper side light shielding layer 27 is formed on the upper side of the light shielding body 23. The upper side light shielding layer 27 includes a light shielding material such as BLK CF, Ti, and W, and has a circular opening portion narrower than each opening portion (the light transmitting portion 25 surrounded by the light shielding wall 26) of the light shielding body 23. A microlens 28 is formed in a circular opening portion of the upper side light shielding layer 27.
Further, note that the opening portion of the lower side light shielding layer 24 may be formed to have either a tapered shape or an inversely tapered shape. Of course, the opening portion may have a vertical shape with no inclination.
Next, a process of forming the upper side light shielding layer 27 and the microlens 28 will be described.
In the case of forming the microlens 28 before forming the upper side light shielding layer 27, as illustrated in
In this case, since there is no upper side light shielding layer 27 for restricting the slippage around the lens material, variations occur in an amount of slippage, which may occur in the shape or the size of each microlens 28. As a result, there is a possibility that a failure such as bending may occur in the obtained image. In order to prevent such a failure, it is preferable that the microlens 28 be formed after forming the upper side light shielding layer 27.
Next,
Further, in the example of
First, as illustrated in
Next, the entire light shielding body 23 on which the lower side light shielding layer 24 is formed is reversed, and as illustrated in
In contrast, in a case where the upper side light shielding layer 27 is formed using Ti or W, as illustrated in
After forming the upper side light shielding layer 27, as illustrated in
In this case, since the upper side light shielding layer 27 for restricting the slippage is already formed around the lens material, the uniformity of the shape and size of each microlens 28 can be improved.
In the examples illustrated in
In the image sensor 20, the light condensed by the microlens 28 in which the periphery thereof is shielded by the upper side light shielding layer 27 transmits through the opening portion (the light transmitting portion 25) of the light shielding body 23 and the opening portion of the lower side light shielding layer 24 and is incident on the light receiving element layer 21.
Here, the opening portion (an opening size) of the upper side light shielding layer 27 has, for example, a circular shape having a diameter of 70 μm, the opening portion (an opening size) of the lower side light shielding layer 24 has, for example, a rectangular shape (a square shape) of 140 μm square, and the opening portion (an opening size) of the light shielding body 23 has, for example, a rectangular shape (a square shape) of 360 μm square. Therefore, the opening portion of the upper side light shielding layer 27 is smaller than the opening portion of the lower side light shielding layer 24.
When the opening size is in such a relation, since the incident light transmits through the opening portion of the lower side light shielding layer 24 narrower than the opening portion of the light shielding body 23 and formed in a rectangular shape, it is possible to suppress the incident light from leaking to the adjacent section. Further, since the degradation of contour resolution of the image formed on the light receiving element is suppressed by the rectangular shape of the opening portion of the lower side light shielding layer 24 as illustrated in
As described above, the light transmitting portion 25 of the light shielding body 23 includes a transparent material such as glass or resin. However, in a case where the transparent material is a glass, α rays are emitted from the glass due to the additive thereof, and the light receiving element of the light receiving element layer 21 may be adversely affected.
Next,
In the second configuration example, the thickness of the thin film joining resin layer 22 for joining the light receiving element layer 21 and the light shielding body 23 is increased to shield the α rays. In this case, the thickness of the thin film joining resin layer 22 may be about 50 μm.
In the second configuration example, since the α ray emitted from the glass forming the light transmitting portion 25 of the light shielding body 23 are shielded by the thin film joining resin layer 22, it is possible to suppress the adverse effect of α rays on the light receiving element of the light receiving element layer 21.
However, in a case where the thickness of the thin film joining resin layer 22 is increased, problems described below may also occur.
Next,
In the third configuration example, the light shielding wall 26 of the light shielding body 23 at the end of the image sensor 20 extends to the side of the thin film joining resin layer 22 to form a convex portion 51.
Regarding the process of forming the convex portion 51 on the light shielding body 23, before a penetration hole serving as the light transmitting portion 25 is opened in the light shielding material, a region serving as the convex portion 51 of the light shielding material is left, other regions may be dug down by the same amount as the thickness of the thin film joining resin layer 22 and then the penetration hole may be opened.
In the third configuration example, since the side of the joining resin layer 22 is shielded by the convex portion 51, it is possible to prevent light from entering from the side of the thin film joining resin layer 22 and being incident on the light receiving element, and deterioration of image quality can be suppressed.
In addition, since the outer exposed area of the thin film joining resin layer 22 is reduced by the convex portion 51, entry of moisture is also suppressed and reliability (for example, moisture resistance) can be improved.
Furthermore, since the rigidity of the image sensor 20 is improved by the convex portion 51 as compared with a state in which the convex portion 51 is absent, warpage of the image sensor 20 can be suppressed.
When a plurality of image sensors 20 formed on the wafer are individually cut (diced), if cutting at a position at which the convex portion 51 is present, it is possible to prevent quality degradation of dicing due to processing of different materials.
Next,
In the fourth configuration example, the light shielding wall 26 of the light shielding body 23 at the end of the image sensor 20 extends to the side of the light receiving element layer 21 to form a convex portion 61.
The formation of the convex portion 61 is similar to that of the third configuration example. However, in the case of the fourth configuration example, it is also necessary to form the region of the light receiving element layer 21 joined with the convex portion 61 into a concave shape.
In the fourth configuration example, since the side of the joining resin layer 22 is shielded by the convex portion 61, it is possible to prevent light from entering from the side of the thin film joining resin layer 22 and being incident on the light receiving element, and the deterioration of the image quality can be suppressed.
In addition, since the outer exposed area of the thin film joining resin layer 22 is reduced by the convex portion 61, entry of moisture is also suppressed and reliability (for example, moisture resistance) can be improved.
Furthermore, since the rigidity of the image sensor 20 is improved by the convex portion 61 as compared with a state in which the convex portion 61 is absent, warpage of the image sensor 20 can be suppressed.
When the plurality of image sensors 20 formed on the wafer are individually cut (diced), if cutting at a position at which the convex portion 61 is present, it is possible to prevent the quality degradation of the dicing due to processing of different materials.
Next,
In the fifth configuration example, the light shielding wall 26 of the light shielding body 23 in the first configuration example of the image sensor 20 illustrated in
As a forming method of forming the light shielding wall 26 into a moth eye structure, for example, it is possible to use a Bosch process which repeats an isotropic etching step of isotropically etching the light shielding body 23 configured by a light shielding material such as Si, and an anisotropic etching step of forming a protective film on a front surface of the light shielding body 23 after the isotropic etching and then etching only a surface (a bottom surface) of the protective film in a depth direction.
Further, as illustrated in
Further, although
In the aforementioned first to fifth configuration examples, as illustrated in
However, as illustrated in
In a case where the opening shape of the upper side light shielding layer 27 is circular, as illustrated in
In contrast, in a case where the opening shape of the upper side light shielding layer 27 is a rectangle (square) which is the same as the opening shape of the variable light shielding layer 24, since unnecessary light is not incident as illustrated in
The present technology is not limited to application to the image sensor. That is, the present technology is applicable to all electronic apparatuses which use a solid-state image pickup device as an image capturing unit (a photoelectric conversion unit), such as an image pickup device such as a digital still camera or a video camera, a portable terminal device having an image pickup function, or a copying machine which uses a solid-state image pickup device as an image reading unit. The solid-state image pickup device may be in a form formed as a single chip or may be in a modular form having an image pickup function in which an image pickup unit and a signal processing unit or an optical system are packaged together.
The image pickup device 100 of
The optical unit 101 captures incident light (image light) from a subject and forms an image on the image pickup surface of the solid-state image pickup device 102. The solid-state image pickup device 102 converts the light amount of the incident light imaged on the image pickup surface by the optical unit 101 into electric signals in pixel units, and outputs the electric signals as pixel signals. As the solid-state image pickup device 102, it is possible to use any one of the image sensors 20 of the first to fifth configuration examples, that is, a solid-state image pickup device in which color mixture, stray light, and degradation of contour resolution are suppressed and the image quality is improved.
The display unit 105 includes, for example, a thin display such as a liquid crystal display (LCD) or an organic electro luminescence (EL) display, and displays a moving image or a still image captured by the solid-state image pickup device 102. The recording unit 106 records a moving image or a still image captured by the solid-state image pickup device 102 on a recording medium such as a hard disk or a semiconductor memory.
The operation unit 107 issues an operation command for various functions of the image pickup device 100 under the operation of the user. The power supply unit 108 appropriately supplies various power sources serving as operating power sources of the DSP circuit 103, the frame memory 104, the display unit 105, the recording unit 106, and the operation unit 107 to the supply targets.
As described above, by using any one of the image sensors 20 of the first to fifth configuration examples as the solid-state image pickup device 102, it is possible to suppress color mixture, stray light, and degradation of contour resolution. Therefore, even in the image pickup device 100 such as a video camera, a digital still camera, or a camera module for a mobile device such as a cellular phone, the image quality of the captured image can be improved.
The image sensor 20 can be used, for example, in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-rays as described below.
Further, the embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications are possible within the scope that does not depart from the gist of the present disclosure.
The present disclosure can also take the following configurations.
(1)
A solid-state image pickup device including:
alight shielding body having light shielding walls and a light transmitting portion formed in an opening portion between the light shielding walls;
a first light shielding layer which is formed on an incident surface side of light of the light shielding body, and has an opening portion narrower than the opening portion of the light shielding body for each of the opening portions of the light shielding body;
a microlens provided on the incident surface side of light of the light shielding body and for each of the opening portions of the first light shielding layer;
a light receiving element layer in which a large number of light receiving elements which perform photoelectric conversion in accordance with incident light condensed by the microlens and input via the light transmitting portion of the light shielding body are arranged; and
a second light shielding layer which is formed on the light receiving element layer side of the light shielding body, and has an opening portion narrower than the opening portion of the light shielding body and wider than the first light shielding layer for each of the opening portions of the light shielding body.
(2)
The solid-state image pickup device according to (1), in which the light shielding wall of the light shielding body has a moth eye structure.
(3)
The solid-state image pickup device according to (2), in which the moth eye structure of the light shielding wall is formed by a Bosch process.
(4)
The solid-state image pickup device according to any of (1) to (3), in which a cross-sectional shape of the light shielding wall of the light shielding body is an inversely tapered shape.
(5)
The solid-state image pickup device according to any of (1) to (4), in which the opening portions of the first light shielding layer and the second light shielding layer have a rectangular shape.
(6)
The solid-state image pickup device according to any of (1) to (4), in which the opening portion of the first light shielding layer has a circular shape, and the opening portion of the second light shielding layer has a rectangular shape.
(7)
A method for manufacturing a solid-state image pickup device including:
forming a first light shielding layer having an opening portion narrower than an opening portion of a light shielding body for each of the opening portions of the light shielding body, on an incident surface side of light of the light shielding body having light shielding walls and a light transmitting portion formed in an opening portion between the light shielding walls;
forming a microlens on the incident surface side of light of the light shielding body and for each of the opening portions of the first light shielding layer; and
forming a second light shielding layer narrower than the opening portion of the light shielding body and wider than the first light shielding layer for each of the opening portions of the light shielding body, on the light receiving element layer side of the light shielding body.
(8)
An electronic apparatus including a solid-state image pickup device, the solid-state image pickup device including:
a light shielding body having light shielding walls and a light transmitting portion formed in an opening portion between the light shielding walls;
a first light shielding layer which is formed on an incident surface side of light of the light shielding body and has an opening portion narrower than the opening portion of the light shielding body for each of the opening portions of the light shielding body;
a microlens provided on the incident surface side of light of the light shielding body and for each of the opening portions of the first light shielding layer;
a light receiving element layer in which a large number of light receiving elements which perform photoelectric conversion in accordance with incident light condensed by the microlens and input via the light transmitting portion of the light shielding body are arranged; and
a second light shielding layer which is formed on the light receiving element layer side of the light shielding body, and has an opening portion narrower than the opening portion of the light shielding body and wider than the first light shielding layer for each of the opening portions of the light shielding body.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-177334 | Sep 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/030856 | 8/29/2017 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2018/047665 | 3/15/2018 | WO | A |
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| Number | Date | Country |
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| 2001-171429 | Jun 2001 | JP |
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| Entry |
|---|
| English Machine translation of Japanese Patent JP 2002-171429 A by Kato Yukihide Date Jun. Year 2002. |
| International Search Report and Written Opinion of PCT Application No. PCT/JP2017/030856, dated Nov. 21, 2017, 10 pages of ISRWO. |
| Number | Date | Country | |
|---|---|---|---|
| 20190206925 A1 | Jul 2019 | US |
