JP2011199036A - Solid-state image pickup device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state image pickup device capable of miniaturizing a product without improving a manufacturing apparatus, and a method for manufacturing the solid-state image pickup device.SOLUTION: The solid-state image pickup device includes a substrate 1, a transparent supporting base substance 3 provided on one surface of the substrate 1, adhesives 5 formed on one surface of the substrate 1 to fix the substrate and the transparent supporting base substance 3, first conductive layers 2 which are formed in a region being an upper part of the transparent supporting base substance 3, and facing the adhesives 5 via the transparent supporting base substance 3, external terminals 7 arranged on the other surface of the substrate 1, and second conductive layers 6 formed in the substrate 1 and connected to the external terminals 7.

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof.

  In recent years, with the miniaturization, there has been a need for high integration and miniaturization of semiconductor devices mounted on electronic equipment. For this reason, WLCSP (Wafer Level Chip Scale Package) for cutting out a wafer after forming a semiconductor device, forming an output terminal, wiring for connecting to an external device, and the like has been put into practical use. In this WLCSP, in place of the lead wire connected to the external device, the surface of the semiconductor chip is reversed, the metal micro bump is provided on the surface, and the flip chip bonding for connecting the metal micro bump and the external device (substrate) is performed. It has been adopted.

  In addition, a stacked package (multi-chip package) in which through electrodes are provided on a silicon wafer for mounting a semiconductor chip and the semiconductor chips are stacked in multiple layers has been developed. When the through electrode is formed on the silicon wafer, the through electrode is formed by adhering the silicon support substrate to the semiconductor chip and fixing the silicon support substrate with an electrostatic chuck.

  Therefore, in a semiconductor device equipped with an optical element, when a through electrode is to be mounted instead of wiring (wire bonding) connected to an external device at the silicon wafer level as described above, the through hole is formed using, for example, dry etching. There is a need to fix the semiconductor device during formation. When trying to fix a semiconductor device on which an optical element is mounted, a silicon material cannot be used for a support substrate for fixing the semiconductor device, and a transparent glass material needs to be used (see Non-Patent Document 1).

  However, glass materials are mixed with metals such as Al, B, and Ca, but they are non-conductive, so it is impossible to fix a semiconductor device equipped with an optical element using an electrostatic chuck. There has been a problem that accuracy is lacked in the formation of the through electrode and the separation into individual pieces.

International Electron Devices Meeting 1999: Technical Digest, WASHINGTON DC DECEMBER 5-8, pp.879-882

  The present invention provides a solid-state imaging device capable of downsizing a product without improving the manufacturing device and a manufacturing method thereof.

  A solid-state imaging device according to an aspect of the present invention includes a semiconductor substrate, a transparent support base provided on one surface of the semiconductor substrate, and the semiconductor substrate formed on the one surface of the semiconductor substrate. An adhesive for fixing the transparent support base; a first conductive layer formed on the transparent support base and in a region facing the adhesive via the transparent support base; and the semiconductor substrate. An external terminal disposed on the other surface; and a second conductive layer formed in the semiconductor substrate and connected to the external terminal.

  According to another aspect of the present invention, there is provided a method for manufacturing a solid-state imaging device, the step of forming an imaging element in the surface of a semiconductor substrate, the step of forming an adhesive on the surface of the semiconductor substrate, and the semiconductor substrate. A step of adhering a transparent support substrate with the adhesive; a step of forming a first conductive layer on the transparent support substrate in a region facing the adhesive; and the semiconductor. Forming a through hole from the back side of the substrate into the semiconductor substrate; embedding a second conductive layer in the through hole; and connecting the external terminal electrically connected to the second conductive layer to the semiconductor Forming on the back surface of the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the solid-state imaging device which enables size reduction of a product, without adding an improvement to a manufacturing apparatus can be provided.

1 is a plan view showing a silicon substrate in a solid-state imaging device according to a first embodiment of the present invention. Sectional drawing along the 2-2 direction of FIG. Sectional drawing which shows the 1st manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 2nd manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 3rd manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 4th manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 5th manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 6th manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 7th manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 8th manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 9th manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the 10th manufacturing process of the solid-state imaging device which concerns on the 1st Embodiment of this invention. 1 is a cross-sectional view of a camera module according to a first embodiment of the present invention. Sectional drawing which shows the manufacturing process of the conductive layer which concerns on the 1st Embodiment of this invention. The top view which shows the silicon substrate in the solid-state imaging device which concerns on the modification of this invention. The top view which shows the silicon substrate in the solid-state imaging device which concerns on the 2nd Embodiment of this invention. FIG. 18 is a cross-sectional view taken along the 18-18 direction in FIG. 17. Sectional drawing in the solid-state imaging device which concerns on the 3rd Embodiment of this invention. Sectional drawing of the camera module which concerns on the 3rd Embodiment of this invention. Sectional drawing of the camera module which concerns on the 1st modification of the 3rd Embodiment of this invention. Sectional drawing of the camera module which concerns on the 2nd modification of the 3rd Embodiment of this invention. Sectional drawing of the camera module which concerns on the 3rd modification of the 3rd Embodiment of this invention. Sectional drawing of the camera module which concerns on the 4th modification of the 3rd Embodiment of this invention. Sectional drawing which shows the 1st manufacturing process in the solid-state imaging device which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the 2nd manufacturing process in the solid-state imaging device which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the 3rd manufacturing process in the solid-state imaging device which concerns on the 4th Embodiment of this invention. Sectional drawing of the camera module which concerns on the 4th Embodiment of this invention. Sectional drawing in the solid-state imaging device which concerns on the modification of the 4th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the description, common parts are denoted by common reference symbols throughout the drawings.

[First embodiment]
A solid-state imaging device and a manufacturing method thereof according to a first embodiment of the present invention will be described with reference to FIGS. First, FIG. 1 will be described. FIG. 1 is a plan view of a plurality of image sensors (not shown) formed on a silicon substrate 1 (image sensor chip) as viewed from the conductive layer 2 side. That is, the image pickup device is divided into pieces by dicing (cutting) the silicon substrate 1 shown in FIG. 1 along the first direction and the second direction at predetermined positions. As a result of this process, for example, a camera module mounted on a mobile phone or the like is formed. An imaging element 4 (not shown) is formed on the surface of the silicon substrate 1, and a conductive layer 2 shown in the figure is formed through a transparent support substrate 3 (hereinafter referred to as a glass substrate 3) such as glass described later. .

  FIG. 1 shows an enlarged view of region A in the plan view. As shown in the drawing, a region (reference numeral 3 in the figure) where the conductive layer 2 is not formed is formed in a mesh shape on the silicon substrate 1. That is, in the region where the conductive layer 2 is not formed, the glass substrate 3 formed immediately below the conductive layer 2 is exposed. That is, light enters the exposed glass substrate 3, and the image sensor receives the incident light.

  Next, FIG. 2 shows a sectional view taken along line 2-2 of FIG. As shown in the figure, solder balls 7 are disposed on the back side of the silicon substrate 1. Then, an electrical signal obtained by receiving light with the image sensor 4 and then photoelectrically converted is output to a host device (not shown) by the solder ball 7.

  A conductive layer 6 (sometimes referred to as a through electrode 6) is formed in the silicon substrate 1. The conductive layer 6 transfers an electrical signal obtained by photoelectrically converting the light received by the image sensor 4 to the solder ball 7. A plurality of image sensors 4 are formed in the surface of the silicon substrate 1. The imaging device 4 includes a photodiode PD, a microlens, a reading transistor, and the like. The photodiode PD is formed of, for example, an n-type diffusion layer formed in the surface of the silicon substrate 1 and accumulates electrons generated in the silicon substrate 1 by receiving light. The microlens condenses light coming from the glass substrate 3 on the photodiode PD. The read transistor has a function of reading electrons accumulated in the diffusion layer. The imaging element 4 is formed in a matrix on the surface of the silicon substrate 1.

  An adhesive 5 is formed on the silicon substrate 1 in a region where the image sensor 4 is not formed. That is, the adhesive 5 is formed at a plurality of locations so as to separate the imaging element 4 formed on the silicon substrate 1. In other words, the imaging element 4 is formed so as to be surrounded by the adhesive 5. A glass substrate 3 is bonded onto the silicon substrate 1 via the adhesive 5. The glass substrate 3 serves as a support substrate for fixing the silicon substrate 1 when the back surface of the silicon substrate 1 is processed. Specifically, when a through hole is provided in the silicon substrate 1 to be described later, it serves as a support substrate for fixing the silicon substrate 1. This support substrate forms part of the camera module and needs to be transparent so that the image sensor 4 can receive light. Therefore, in this embodiment, glass is used as the material. The plurality of conductive layers 2 described above are formed on the glass substrate 3. These conductive layers 2 are formed immediately above the adhesive 5. In other words, the conductive layer 2 is formed in a region facing the adhesive 5 that bonds the silicon substrate 1 and the glass substrate 3 to the glass substrate 3. That is, a region facing the imaging element 4 formed in the surface of the silicon substrate 1 is exposed to the glass substrate 3. Thereby, light incident from the conductive layer 2 side passes through the glass substrate 3 and can be received by the image sensor 4.

<Manufacturing process>
Next, a method for manufacturing the solid-state imaging device will be described with reference to FIGS. First, as shown in FIG. 3, a conductive layer 2 is formed on a glass substrate 3 by, for example, sputtering or vapor deposition, and a resist film 10 is formed on the conductive layer 2. The conductive layer 2 is formed of a metal such as Al, Ti, Ni, Pt, Au, Cu, and Cr. Then, as shown in FIG. 4, the resist film 10 and the conductive layer 2 are subjected to predetermined patterning, and then, for example, etching is performed. Thereby, the surface of the glass substrate 3 is exposed. At this time, the width of the conductive layer 2 and the resist film 10 to be formed is W0. Then, as shown in FIG. 5, the resist film 10 remaining on the conductive layer 2 is removed by, for example, etching.

  Next, as shown in FIG. 6, the imaging element 4 is formed on the silicon substrate 1 by a known method. As described above, the imaging element 4 includes an n-type diffusion layer, a microlens, a readout transistor, and the like. Then, as shown in FIG. 7, a photosensitive or non-photosensitive adhesive 5 is formed in a region of the silicon substrate 1 where the imaging element 4 is not formed. Specifically, when a photosensitive material is used for the adhesive 5, the adhesive 5 is formed on the silicon substrate 1 by spin coating or lamination, and is formed in the region where the imaging element 4 is formed. The adhered adhesive 5 is removed by exposure and development. When a non-photosensitive material is used for the adhesive 5, the adhesive 5 is printed on the silicon substrate 1 by a method such as silk screen printing or ink jet printing in addition to the region where the imaging element 4 is formed. The adhesive 5 is a photosensitive or non-photosensitive epoxy resin, polyimide resin, acrylic resin, or silicone resin, or a mixture thereof.

  Next, as shown in FIG. 8, the glass substrate 3 on which the conductive layer 2 shown in FIG. 5 is formed and the silicon substrate 1 shown in FIG. Specifically, the bottom surface of the glass substrate 3 and the imaging element 4 formation surface of the silicon substrate 1 are bonded with an adhesive 5. Hereinafter, a state in which the glass substrate 3 and the silicon substrate 1 are bonded together is referred to as a solid-state imaging device.

  Then, as shown in FIG. 9, the solid-state imaging device is inverted 180 degrees so that the bottom surface of the silicon substrate 1 shown in FIG. 8 is on the upper surface side and the conductive layer 2 is on the lower surface side. Then, as shown in FIG. 9, with the silicon substrate 1 facing upward, the silicon substrate 1 is polished by, for example, the BG (Backside Grinding) method, and the thickness is reduced to about 100 μm. Thereby, it becomes easy to form a through hole in the silicon substrate 1.

  Next, as shown in FIG. 10, through holes 11 are formed from the back surface side to the front surface side of the silicon substrate 1 using, for example, anisotropic etching. This anisotropic etching is performed using a wiring layer (not shown) constituting the image sensor 4 as a stopper. That is, the bottom surface of the through hole 11 reaches a wiring layer (not shown). The wiring layer is a wiring for transmitting an electric signal photoelectrically converted by the photodiode PD to the solder ball 7, and is formed of, for example, Al, AlCu, AlSiCu, Cu or the like. In addition to the anisotropic etching, the through holes 11 may be formed by a method such as wet etching, laser, or micro drill. The solid-state imaging device is fixed using an electrostatic chuck in anisotropic etching. That is, positive and negative charges are generated on the surface of an adsorption stage (not shown), and the conductive layer 2 is fixed to the adsorption stage by electrostatic force acting between the charges.

  Next, after forming an insulating film (not shown) on the surface of the through hole 11 by, for example, a CVD (Chemical Vapor Deposition) method, the insulating film stacked on the bottom of the through hole 11 is removed by, for example, etching. Then, as shown in FIG. 11, the through hole 11 is filled with the conductive layer 6 by using, for example, a sputtering method. Thereafter, solder balls 7 are arranged on the back surface of the silicon substrate 1. Thereby, the solid-state imaging device shown in FIG. 2 is formed. The conductive layer 6 embedded in the through-hole 11 may use a method such as vapor deposition, CVD, or plating in addition to the sputtering method.

  Next, the silicon substrate 1 is diced at the position of the broken line shown in FIG. As a result, a plurality of image sensors 4 formed on the silicon substrate 1 are separated into individual pieces, and a predetermined process is applied to these image sensors 4 to form the camera module shown in FIG. As shown in FIG. 13, in addition to the structure of FIG. 12, the camera module further includes an infrared cut glass (IR cut glass) 20, a light shielding / electromagnetic shield 21, an imaging lens 22, 23, a lens holder 24, a cover glass 25, and a back surface. A rewiring 26 and a protective film 27 are provided. As illustrated, a lens holder 24 is provided on the conductive layer 2 via an adhesive 28. That is, the IR cut glass 20 and the imaging lenses 22 and 23 are fixed on the glass substrate 3 by the lens holder 24. The light shielding and electromagnetic shield 21 is formed so as to cover the silicon substrate 1, the adhesive 5, the glass substrate 3, the conductive layer 2, the adhesive 28, the lens holder 24, and the imaging lenses 22 and 23. The module is configured.

  Further, a back surface rewiring 26 and a protective film 27 are formed on the bottom surface of the silicon substrate 1. The back surface rewiring 26 is provided on the bottom surface of the silicon substrate 1 in order to electrically connect the conductive layer 6 and the solder ball 7. The protective film 27 is provided on the bottom surface of the silicon substrate 1 so as to protect the back surface rewiring 26.

<Effects according to this embodiment>
The solid-state imaging device and the manufacturing method thereof according to the present embodiment can achieve the following effects.

(1) A small-sized image sensor can be formed without improving the existing semiconductor device manufacturing apparatus.
First, a description will be given with a comparative example. The same reference numerals are used for the same configurations as those of the solid-state imaging device according to the present embodiment.
As described above, when the glass substrate 3 is used as the support substrate, since the glass does not have conductivity, there is a problem that the silicon substrate 1 cannot be fixed by the electrostatic chuck when the through hole 11 is provided. is there.

  Therefore, a conductive sheet is attached to the surface of the glass substrate 3, and the solid-state imaging device is fixed to the suction stage. Then, through a predetermined process, a solid-state imaging device as shown in FIG. 13 is manufactured. However, there are the following problems when peeling the conductive sheet.

(1) The process of peeling the conductive sheet increases, which takes time.
(2) When the conductive sheet is peeled off, an adhesive (glue) may remain, and the surface of the glass substrate 3 becomes dirty. That is, if the remaining adhesive is directly above the pixels, it may become dust and cause image defects.
(3) When sticking, air remains between the sheet and the glass substrate 3, and when it is put into a vacuum device (chamber) as it is and the pressure is lowered, the remaining air expands and the sheet bursts. End up. At this time, since the silicon substrate 1 is thin, the silicon substrate 1 itself may be destroyed.
(4) The conductive sheet has a characteristic that the heat-resistant temperature is low. For this reason, the upper limit of temperature at the time of performing heat treatment etc. in a manufacturing process will be restricted. Since the adhesive 5 and the color filter resist also have temperature limitations, the temperature limitation is not limited to the conductive sheet.
The problems (1) to (4) are defined as problem 1.

  It is also assumed that data is output to an external device using a bonding wire. That is, the data converted into the electrical signal by the image sensor 4 is output to the external device via the bonding wire. However, recently, when bonding wires are used with miniaturization, the solid-state imaging device itself becomes bulky, and the chip scale (camera module) increases. This is problem 2.

  In this respect, the above-described problem 1 and problem 2 can be solved by the solid-state imaging device and the manufacturing method thereof according to the present embodiment. In the solid-state imaging device and the manufacturing method thereof according to the present embodiment, the conductive layer 2 is formed on the glass substrate 3 by, for example, vapor deposition or sputtering, instead of the sheet for fixing the solid-state imaging device. Then, the solid-state imaging device is fixed to the suction stage using the conductive layer 2. Then, the conductive layer 2 is removed from a region facing the region where the image sensor 4 is formed so that the image sensor 4 can receive light. In other words, the glass substrate 3 is exposed in accordance with the position where the image sensor 4 is formed. For this reason, it is not necessary to peel off the conductive layer 2 even after dicing, and there is no problem of the above (1) and (2). That is, if there is no step of peeling off the conductive layer 2, the surface of the glass substrate 3 becomes dirty and the problem of image defects can be avoided.

  Of course, since the conductive layer 2 is deposited in a vacuum apparatus, there is no problem that air remains in the gap between the conductive layer 2 and the glass substrate 3 as in (3) above. Furthermore, since the heat resistance temperature of the conductive layer 2 is high, it is not necessary to consider temperature limitation in the manufacturing process. That is, there is no problem of the above (4).

  Furthermore, in this embodiment, instead of the bonding wire, the conductive layer 6 is embedded in the through hole 11 in the silicon substrate 1. For this reason, the problem that a chip | tip becomes bulky can also be suppressed.

  As described above, the solid-state imaging device and the manufacturing method thereof according to this embodiment can fix the solid-state imaging device to the electrostatic chuck while solving the problems 1 and 2. That is, the formation of the through hole 11 and the dicing of the silicon substrate 1 can be performed after solving the problems 1 and 2. In other words, a small image sensor can be created without improving the substrate holding device that fixes the solid-state image pickup device.

  As described in the solid-state imaging device and the manufacturing method thereof according to the first embodiment, the method for forming the conductive layer 2 shown in FIGS. 3 to 5 may be performed by another method. This will be described with reference to FIG. FIG. 14 shows a manufacturing process for forming the conductive layer 2 on the silicon substrate 1. As shown in the figure, a T-shaped resist film 29 is formed in a region other than the region where the conductive layer 2 is to be formed, and then the conductive layer 2 is formed by, for example, sputtering or vapor deposition. Thereafter, the resist film 29 is removed by, for example, wet etching. Thereby, a configuration as shown in FIG. 5 in the first embodiment is formed.

<Modification according to this embodiment>
Next, a solid-state imaging device and a manufacturing method thereof according to a modification of the first embodiment will be described. In the solid-state imaging device and the manufacturing method thereof according to the modification, the conductive layer 2 formed on the glass substrate 3 is formed in a polka dot shape. This will be described with reference to FIG. FIG. 15 is an enlarged plan view in the case where the conductive layer 2 is formed in a polka dot shape in FIG. 1 in the first embodiment. As shown in the drawing, the glass substrate 3 is exposed except for the conductive layer 2 formed in a polka dot shape.

  In the method of manufacturing the solid-state imaging device according to the modification, the mask is formed in a polka dot shape when the resist film is deposited. Thereby, a resist film is made into a polka dot shape. The shape of the conductive layer 2 is not limited to the polka dot shape, and may be any shape, such as a square shape or a hexagonal shape, as long as it is separated.

<Effect according to modification>
According to the solid-state imaging device and the manufacturing method thereof according to the modified example, the following effects can be obtained in addition to the effect (1) of the first embodiment.

(2) The quality can be improved.
In the solid-state imaging device and the manufacturing apparatus thereof according to the modification, the conductive layer 2 is peeled off from the glass substrate 3 or the glass substrate 3 is warped when the conductive layer 2 is cooled from a high temperature by heat treatment such as reflow. Can be prevented. Metal and glass have different coefficients of thermal expansion. Metal has a higher coefficient of thermal expansion (coefficient) than glass. That is, a metal has physical properties that it is easy to stretch and shrink compared to glass. That is, when the metal cools after performing a heat treatment such as reflow, the shrinkage of the metal is larger than that of the glass, so that the conductive layer 2 may peel off from the glass substrate 3 or warp the glass substrate 3. For example, when the conductive layer 2 is formed on the entire surface of the glass substrate 3, the force to peel off or warp is large. However, as shown in the modification, the conductive layer 2 is formed in a polka dot shape. That is, the area of the conductive layer 2 occupying on the glass substrate 3 is smaller than that of the first embodiment. For this reason, since the force to shrink is generated in a small area, a large force (force to shrink) does not work on the entire glass substrate 3, and the conductive layer 2 is not easily peeled off or warped after the heat treatment. It is possible to achieve such an effect. From this, the solid-state imaging device can be fixed by an electrostatic chuck, and the through hole 11 can be accurately formed in the silicon substrate 1 and the silicon substrate 1 can be diced.

[Second Embodiment]
Next, a solid-state imaging device and a method for manufacturing the same according to a second embodiment of the present invention will be described. In the present embodiment, in the first embodiment, the conductive layer 2 formed on the glass substrate 3 is excluded from the region to be diced (dicing line).

  This will be described with reference to FIGS. First, FIG. 16 will be described. FIG. 16 is a plan view of the solid-state imaging device. As shown in the drawing, the conductive layer 2 is not formed on the dicing lines along the first direction and the second direction, and the glass substrate 3 is exposed. That is, the conductive layer 2 formed on the glass substrate 3 is removed from the dicing line. Region A is enlarged to show this situation. As shown in the enlarged view of the region A, each glass substrate 3 exposed to enter the image sensor 4 is formed independently by the rectangular conductive layer 2.

  Next, FIG. 17 is a sectional view taken along the line 18-18 in FIG. 17 is a cross-sectional view of the solid-state imaging device shown in FIG. As shown in the drawing, conductive layers 2 having a width W2 are formed on a glass substrate 3 at intervals of a width W1. That is, dicing is performed in the region having the width W1. Since the configuration other than the above is the same as that of the first embodiment, a description thereof will be omitted.

<Manufacturing process>
Next, the manufacturing process of the solid-state imaging device according to this embodiment will be described. The solid-state imaging device according to the present embodiment is patterned so that the remaining conductive layer 2 and the width W0 of the resist film 10 formed on the conductive layer 2 in FIG. 4 of the first embodiment become W2. Do. Specifically, the conductive layer 2 and the resist film 10 are also patterned in a region to be a dicing line in the width W0 in FIG. Thereafter, the resist film 10 is removed using, for example, etching, whereby FIG. 17 can be obtained. Since other steps are the same, description thereof is omitted.

<Effects according to this embodiment>
Even in the solid-state imaging device and the manufacturing method thereof according to the present embodiment, the effect (1) can be obtained. That is, even when the area of the conductive layer 2 formed on the glass substrate 3 is reduced, the solid-state imaging device is fixed to the suction stage using an electrostatic chuck, and the through hole 11 is formed in the dicing and silicon substrate 1. Can be provided.

[Third Embodiment]
Next, a solid-state imaging device and a method for manufacturing the same according to a third embodiment of the present invention will be described. In the solid-state imaging device according to the present embodiment, the upper surface of the exposed glass substrate 3 and the lower surface opposite to the upper surface are made convex in the first embodiment. The description of the same structure as that of the first embodiment is omitted.

  This is shown in FIG. As shown in the drawing, the shape of the region where the glass substrate 3 is exposed in the first embodiment is a convex shape from the previous plane. Specifically, on the upper surface side of the glass substrate 3, the glass substrate 3 is formed such that the convex portion is located at the center of the adjacent conductive layer 2. And it forms so that the convex part of the glass substrate 3 may be located in the center part of the adjacent adhesive agent 5 in the bottom face side of the glass substrate 3. FIG. That is, the upper surface and the bottom surface of the glass substrate 3 each have a convex shape, thereby functioning as a single lens. That is, light enters from the upper surface side of the glass substrate 3. Then, the light coming from the convex bottom surface side is refracted and collected on the microlens. That is, more light is collected on the microlens. The glass shape is not limited to the biconvex lens as shown in FIGS. 18 and 19, but may be a lens having a light condensing property, and may be a lens having a combination of irregularities such as a single concave lens, single convex lens or meniscus lens.

<Manufacturing method>
Next, a method for manufacturing the solid-state imaging device according to this embodiment will be described. In addition, description is abbreviate | omitted about the manufacturing process same as the said 1st Embodiment. The solid-state imaging device according to the present embodiment performs etching so that the glass substrate 3 has a convex shape in the first embodiment, for example, in FIG. Specifically, for example, the etching time on both sides of the glass substrate 3 having a convex shape may be set longer than that of the central portion. Further, also on the bottom surface of the glass substrate 3, the bottom surface of the glass substrate 3 is masked with, for example, a resist film, and the exposed glass substrate 3 is etched as in the top surface of the glass substrate 3, thereby the glass substrate 3. The shape of the substrate 3 may be a convex shape. With the manufacturing method as described above, the exposed surface of the glass substrate 3 can be formed into a convex shape. Alternatively, a plate-like matrix lens may be formed by a die pressing method using a mold in which the lens shapes are arranged vertically and horizontally.

<Effects according to this embodiment>
In the solid-state imaging device and the manufacturing method thereof according to the present embodiment, the following effect (3) can be obtained in addition to the effect (1).
(3) Cost reduction can be realized.
In the solid-state imaging device and the manufacturing method thereof according to the present embodiment, the glass substrate 3 functions to condense light onto the microlens. That is, originally, as described with reference to FIG. 13 of the first embodiment, the lens holder 24 is provided with, for example, two imaging lenses 22 and 23 and refracted by these imaging lenses 22 and 23. Focus the light onto the microlens. The larger the number of pixels, the greater the number of imaging lenses required. That is, there is a problem that costs increase with the number of pixels. However, in the present embodiment, since the glass substrate 3 has a function as a lens, a configuration in which any one of the imaging lenses 22 and 23 in the first embodiment is provided can be employed. This is shown in FIG. FIG. 19 shows a camera module according to this embodiment. As shown in the figure, the glass substrate 3 has a convex shape, and only the imaging lens 22 is formed on the glass substrate 3. In this way, the light refracted by the imaging lens 22 is further refracted by the glass substrate 3 and condensed on the microlens. From the above, since the glass substrate 3 has a function as a lens, the number of imaging lenses mounted on the camera module can be reduced, and the cost can be reduced.

  In addition, the shape of the exposed glass substrate 3 is not restricted to a convex shape. In other words, the shape is not limited to the convex shape shown in the present embodiment as long as the glass substrate 3 is a flat curved surface and functions as a lens as a result. Such an example is shown in FIGS. 20 to 23 are sectional views of camera modules according to first to fourth modifications of the present embodiment.

  First, as shown in FIG. 20, the glass substrate 3 may be convex only on the surface facing the image sensor 4, or only the surface facing the lens 22 is convex as shown in FIG. May be. Further, as shown in FIG. 22, only the surface facing the image sensor 4 may be concave. Further, as shown in FIG. 23, the surface facing the image sensor 4 may be concave, and the surface facing the lens 22 may be convex. Note that in the case where the shape has at least one of the convex shapes, the apex thereof is located on the inner side of the surrounding portion (the portion surrounding the convex portion and in contact with the wiring 2 or the adhesive 5).

[Fourth Embodiment]
Next, a solid-state imaging device and a method for manufacturing the same according to a fourth embodiment of the present invention will be described. In the solid-state imaging device according to the present embodiment, the IR cut filter mounted on the camera module shown in the first and third embodiments is formed on the glass substrate 3 without providing the lens holder 24. A method for manufacturing the solid-state imaging device according to the present embodiment will be described with reference to FIGS.

  First, a description will be given with reference to FIG. FIG. 24 shows an IR cut filter 30 formed on the glass substrate 3 in FIG. 3 in the first embodiment. That is, the IR cut filter 30, the conductive layer 2, and the resist film 10 are sequentially formed on the glass substrate 3. Then, as shown in FIG. 25, only the resist film 10 and the conductive layer 2 are patterned so that the IR cut filter 30 remains on one surface of the glass substrate 3. Thereafter, as shown in FIG. 26, the resist film 10 is removed using, for example, etching. Thereby, the IR cut filter 30 is formed on the glass substrate 3, and the conductive layer 2 is formed on the IR cut filter 30. As described above, the IR cut filter 30 described in the first embodiment may be formed on the glass substrate 3. FIG. 27 shows a camera module when the IR cut filter 30 is formed on the glass substrate 3 in this way. FIG. 27 is a configuration diagram of a camera module according to the present embodiment. Only the structure different from that in FIG. 13 used in the first embodiment will be described. As shown in the figure, the IR cut filter 30 that has been provided in the lens holder 21 until then is provided between the conductive layer 2 and the glass substrate 3.

<Effects according to this embodiment>
Even the solid-state imaging device and the manufacturing method thereof according to the present embodiment can achieve the same effects as the above (1). That is, even if the IR cut filter 30 is not provided on the lens holder 24 but formed on the glass substrate 3, the light from which near infrared rays are cut can be condensed onto the microlens. That is, since it is only necessary to cut infrared rays before the light is collected on the microlens, the IR cut filter 20 may be provided in the lens holder 24 as described in the first embodiment, or the present embodiment. The IR cut filter 30 may be formed on the glass substrate 3 as in the form.

  In this embodiment as well, the lens may have a shape as shown in FIGS.

  The IR cut filter 30 may be formed so as to cover the exposed glass substrate 3 in the structure of FIG. 5 of the first embodiment. This is shown in FIG. As illustrated, the conductive layers 2 and the IR cut filters 30 are alternately formed on the silicon substrate 3. Even with such a configuration, the light from which the near-infrared light has been cut by the IR cut filter 30 can be received by the imaging device 4 after passing through the glass substrate 3.

  In addition, the shape of the exposed glass substrate 3 in the said 1st thru | or 4th embodiment is not restricted to a rectangle. That is, as long as the image sensor 4 can receive light, the shape of the exposed glass substrate 3 can be deformed into various shapes such as a circle and a square.

  Then, the exposed area of the glass substrate 3 may be increased so that more light is incident on the imaging element 4. In other words, for example, the imaging element 4 may receive more light by setting the width W0 of the conductive layer 2 illustrated in FIG. 2 to, for example, W3 (<W0).

  The shape of the conductive layer 2 may be linear or polygonal as long as the conductive layer 2 is not formed on the image sensor 4.

  Further, the supporting substrate is not limited to the glass substrate 3 as long as it functions as a supporting substrate for the silicon substrate 1 and can transmit visible light. That is, as long as it is colorless and transparent, it may be a support substrate using plastic or the like as a material.

  In the first to fourth embodiments, the adhesive 5 is formed on the silicon substrate 3 so as to surround the image sensor 4. However, the adhesive 5 is formed so as to cover the image sensor 4. It may be. In other words, the silicon substrate 1 and the glass substrate 3 may be bonded to each other with the adhesive 5 also in the region where the image sensor 4 is formed. That is, if the light incident from the glass substrate 3 toward the adhesive 5 is a material having a refractive index that is refracted in the adhesive 5, the adhesive 5 is formed to cover the imaging element 4. It may be. Specifically, since the refractive index of the glass substrate 3 is about 1.5, in order for light to be refracted in the adhesive 5, the adhesive 5 made of a material having a refractive index of about 1.3. If it is.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

  DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2, 6 ... Conductive layer, 3 ... Glass substrate, 4 ... Imaging element, 5, 28 ... Adhesive, 7 ... Solder ball, 10, 12 ... Resist film, 11 ... Through-hole, 20, 30 ... IR cut filter, 21 ... light shielding / electromagnetic shield, 22, 23 ... imaging lens, 24 ... lens holder, 26 ... back surface rewiring, 27 ... protective film

Claims (4)

A semiconductor substrate;
A transparent support base provided on one surface of the semiconductor substrate;
An adhesive formed on the one surface of the semiconductor substrate and fixing the semiconductor substrate and the transparent support base;
A first conductive layer on the transparent support substrate, the first conductive layer formed in a region facing the adhesive via the transparent support substrate;
An external terminal disposed on the other surface of the semiconductor substrate;
And a second conductive layer formed in the semiconductor substrate and connected to the external terminal. A first region whose surface is exposed without being covered with the first conductive layer on an upper surface of the transparent support substrate; and a second region which is opposed to the first region on a lower surface of the transparent support substrate. 2. The solid-state imaging device according to claim 1, wherein at least one of the surfaces has a convex or concave surface shape. The solid-state imaging device according to claim 1, further comprising an absorption film on the transparent support base. Forming an image sensor in the surface of the semiconductor substrate;
Forming an adhesive on the surface of the semiconductor substrate;
Bonding a transparent support base on the semiconductor substrate with the adhesive;
Forming a first conductive layer on the transparent support substrate in a region facing the adhesive with respect to the transparent support substrate;
Forming a through hole from the back side of the semiconductor substrate into the semiconductor substrate;
Burying a second conductive layer in the through hole;
And a step of forming an external terminal electrically connected to the second conductive layer on the back surface of the semiconductor substrate.

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