JP2012169528A - Solid state image pickup device and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid state image pickup device with a narrow gap in which the adhesive force between a cover glass and an image sensor chip is strong.SOLUTION: The solid state image pickup device includes: an image sensor chip 102 having a light receiving element 104 and an electrode 109 for outputting a signal output from the light receiving element 104 to the outside; a micro lens 103 formed on the light receiving element 104; a protective layer 107 formed on the outer periphery of the light receiving element 104; a cover glass 101 provided above the image sensor chip 102 and formed with an optical element 105; a spacer 106 formed on the cover glass 101 for controlling the gap between the cover glass 101 and the light receiving element 104; and an adhesive layer 108 for bonding the spacer 106 and the protective layer 107.

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof, and more particularly to a narrow gap solid-state imaging device and a manufacturing method thereof.

In recent years, digital cameras and digital video cameras have been made thinner and smaller, and solid-state imaging devices composed of CCD (Charge Coupled Device) and CMOS (complementary metal oxide semiconductor) are also being made thinner and smaller. Is required. In order to meet this requirement, the packaging method of the solid-state imaging device is shifting from the conventional type in which the image sensor chip is hermetically sealed with a ceramic package or the like to a chip size package type that can be further downsized.
Recently, solid-state imaging devices are used in a wide variety of applications such as mobile phones, personal digital assistants, and in-vehicle cameras, and demands for thinning, downsizing, and high performance are increasing.
The chip-size package solid-state imaging device has a structure in which the outer periphery of the light receiving portion of the image sensor chip is surrounded by a spacer, a cover glass is bonded onto the spacer, and the light receiving portion is hermetically sealed. Has also been proposed. In addition, a technique is considered in which information other than the amount of light is added by providing an optical element such as a polarizing filter or a color filter on the lower surface of the cover glass (the surface on the image sensor side).

In such a solid-state imaging device, since different polarization information and color information are incident on each pixel of the solid-state imaging device, the optical element is also divided into regions corresponding to the pixels of the solid-state imaging device. Here, if the gap between the optical element and the solid-state imaging element is large, light spreads due to diffraction, and crosstalk occurs.
In order to solve this problem, a spacer is produced by patterning a photosensitive resin having a thickness of 10 μm or less on the cover glass, and the spacer portion is abutted against the image sensor and thermocompression bonded, thereby obtaining a thickness of 10 μm. A technique for integrating a solid-state imaging device and a cover glass in which various optical elements are formed with the following gap is considered and already known.
In Patent Document 1, when packaging is performed with a package sealing width as narrow as about 100 μm, the substrate warps due to the difference in thermal expansion coefficient between the cover glass and the image sensor, and the cover glass and the sensor chip are peeled off. In order to prevent this, an optical plate having a thermal expansion coefficient close to that of the image sensor is sandwiched between the sensor chip and the cover glass, and a solid-state imaging device using a UV curable resin or a thermosetting resin is used for joining each part and a manufacturing method thereof. It is disclosed.

However, the narrow gap solid-state imaging device using a photosensitive organic material has a weak adhesive force, and the cover glass and the image sensor are peeled off by physical impact or thermal shock. For this reason, the adhesive force between the cover glass and the image sensor must be reinforced with resin after the image sensor is die-bonded to the drive substrate. For this reason, there existed a problem that the addition of a reinforcement process and material cost will increase.
In the method using the silicon substrate described in Patent Document 1 as the spacer, since the spacer thickness is several tens to several hundreds of μm, a cross between the pixel of the solid-state image sensor and each region of the optical element corresponding thereto is present. We cannot solve the problem of talk.
The present invention has been made in view of the above points, and an object of the present invention is to provide a narrow gap solid-state imaging device having a strong adhesive force between a cover glass and an image sensor.
It is another object of the present invention to provide a manufacturing method for efficiently manufacturing a narrow gap solid-state imaging device having a strong adhesive force between a cover glass and an image sensor.

In order to achieve the above object, a first embodiment of the present invention includes a light receiving element, an electrode for outputting a signal output from the light receiving element to the outside, the light receiving element, and a substrate that supports the electrode on one surface. An image sensor chip; a microlens formed on a light receiving surface of the light receiving element; a cover glass having an optical element formed on a surface opposed to the light receiving element and spaced apart from the light receiving surface of the light receiving element; A bonding portion that bonds between the substrate and the cover glass on the outer diameter side of the light receiving element, and the bonding portion is fixed to the cover glass surface and bonded to the substrate A spacer for controlling a gap between the glass and the light receiving element, and an adhesive layer for joining the spacer and the substrate are provided.
According to the embodiment of the present invention, the gap between the cover glass and the image sensor chip can be narrowed, so that noise caused by crosstalk is reduced and accurate information can be obtained.
The second aspect of the present invention is characterized in that the spacer has a thickness of 10 μm or less.
The third aspect of the present invention is characterized in that the adhesive layer is 1 μm or less.

According to a fourth aspect of the present invention, the adhesive layer is a UV curable resin or a thermosetting resin.
According to a fifth aspect of the present invention, the bonding portion is made of the same material as the microlens, includes a protective layer fixed to one surface of the substrate, and the adhesive layer is interposed between the spacer and the protective layer. Is formed.
The protective layer is made of the same material as the microlens.
A sixth aspect of the present invention is characterized in that the electrode is formed on a surface different from a substrate surface on which the light receiving element is formed.
According to the embodiment of the present invention, since the bonding area of the image sensor chip can be increased, the bonding force between the cover glass and the image sensor chip can be further increased.

The seventh aspect of the present invention is characterized in that a groove is formed on the surface of the spacer.
According to the embodiment of the present invention, an excess resin material can escape to the groove of the spacer, so that it is possible to prevent the resin from protruding on the light receiving region or the electrode.
The eighth aspect of the present invention is characterized in that a groove is formed from the surface of the spacer to the inside of the cover glass.
According to the embodiment of the present invention, an excess resin material can be released to the grooves formed in the spacer and the glass cover, so that the resin can be prevented from protruding onto the light receiving region or the electrode.
According to a ninth aspect of the present invention, there is provided a manufacturing method of the solid-state imaging device according to the first embodiment, and the manufacturing method of the solid-state imaging device according to the first aspect, wherein the material of the optical element is provided on the cover glass. Depositing or coating the material, patterning the material to form an optical element having desired optical properties, depositing or coating a spacer material on the cover glass, and forming a spacer material layer having a desired thickness. A step of forming, a step of removing the spacer material layer and patterning to a desired shape, a step of dropping a trace amount of UV curable resin or thermosetting resin on the spacer formed by patterning the spacer material layer, Aligning and crimping the cover glass to an image sensor chip, and then curing the UV curable resin or the thermosetting resin to form an adhesive layer; And wherein the Mukoto.
According to the embodiment of the present invention, the bonding force between the cover glass and the image sensor chip can be improved while the distance between the light receiving element and the optical element is controlled to be a narrow gap.

According to the solid-state imaging device of the present invention, accurate optical information with little deterioration can be obtained.
According to the method for manufacturing a solid-state imaging device of the present invention, the reinforcement in the subsequent process is not necessary, so that the manufacturing process can be simplified and the material cost can be reduced.

It is sectional drawing of the solid-state imaging device which concerns on embodiment of this invention. It is the figure which showed an example of the process of the solid-state imaging device which concerns on embodiment of this invention. It is sectional drawing of the solid-state imaging device which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the solid-state imaging device which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the solid-state imaging device which concerns on the 4th Embodiment of this invention.

FIG. 1 is a cross-sectional view of a solid-state imaging device according to an embodiment of the present invention.
A solid-state imaging device 10 according to this embodiment shown in FIG. 1 includes a light receiving element 104, an electrode 109 for transmitting a signal output from the light receiving element 104 to the outside, and a substrate 100 that supports the light receiving element 104 and the electrode 109 on one surface. The image sensor chip 102, the condensing microlens 103 formed on the light receiving surface side of the light receiving element 104, and the light receiving surface of the light receiving element 104 are spaced apart from each other. The cover glass 10-1 on which the optical element 105 is formed, and a joint 110 that joins the substrate 100 and the cover glass 101 on the outer diameter side (outer peripheral side) of the light receiving element 104. The bonding part 110 includes a protective layer 107 fixed to one surface of the substrate 100 and a gap between the cover glass 101 fixed to the surface of the cover glass 101 facing the protective layer 107 and bonded to the protective layer 107 and the light receiving element 104. A control spacer 106 and an adhesive layer 108 for joining the spacer 106 and the protective layer 107 are provided.

The protective layer 107 is provided to protect the wiring on the substrate 100. The cover glass 101 is provided to prevent dust from adhering to the light receiving area of the image sensor chip 102. The total adhesion 108 is provided to improve the bonding force between the cover glass 101 and the image sensor chip 102. In this case, the output of the light receiving element 104 is taken out from the electrode 109 formed on the surface (substrate surface) side of the substrate 100 of the image sensor chip 102.
In the solid-state imaging device 100 configured as described above, light passes through the cover glass 101 and the optical element 105 and enters the light receiving element 104. When light passes through the optical element 105, information other than the light amount such as polarization information and color information can be obtained. Further, the gap between the cover glass 101 and the image sensor chip 102 is controlled by a spacer 106 to a narrow interval of 10 μm, so that light that has passed through a certain region of the optical element 105 spreads due to light diffraction, and is spread in that region. It can prevent entering into pixels other than the pixel of the corresponding light receiving element 105.

Further, the adhesive layer 108 can be formed to a thickness of about 100 nm by applying a pressure after dropping a very small amount of resin, so that the gap between the cover glass 101 and the image sensor chip 102 is not widened. Therefore, in the solid-state imaging device 10 configured as described above, noise caused by crosstalk is reduced, and accurate information can be obtained.
Further, the provision of the adhesive layer 108 eliminates the need to reinforce the joint between the cover glass 101 and the image sensor chip 102 by applying a resin in a later process, and the manufacturing process can be simplified as will be described later.

FIG. 2 is a diagram illustrating an example of a manufacturing process of the solid-state imaging device according to the embodiment of the present invention.
First, in the step shown in FIG. 2A, the material 201 of the optical element 105 is deposited or applied on the cover glass 101. Various materials can be used as the material 201 depending on the type of the optical element 105.
Next, in the step shown in FIG. 2B, the material 201 is patterned to form the optical element 105 having desired optical characteristics.
The manufacturing method of the optical element 105 is not limited to the method of depositing the material 201 on the cover glass 101 and patterning it as in the steps shown in FIGS. It is also possible to develop an optical function by forming a material or depositing a material on a cover glass like an antireflection film.
After the optical element 105 is formed on the cover glass 101, a spacer material layer 202 having a desired thickness is formed by depositing or coating the material of the spacer 106 on the cover glass 101 in the step shown in FIG. To do.
2D, the spacer material layer 202 is patterned into a desired shape by a removal process such as development, etching, and lift-off. The spacer 106 may be formed in a desired pattern from the beginning using a stencil mask or the like as a spacer material.

Next, in the process shown in FIG. 2E, a very small amount of UV curable resin or thermosetting resin 203 is dropped on the spacer 106, and in the process shown in FIGS. The cover glass 101 and the image sensor chip 102 are aligned and pressure-bonded so that the corresponding areas of the pixel and the optical element 105 do not shift.
After the pressure bonding, if the used resin is a UV curable resin, UV irradiation is performed. If the used resin is a thermosetting resin, the resin is heated to cure the resin, and the adhesive layer 107 is formed.
Through the above steps, the bonding force between the cover glass 101 and the image sensor chip 102 can be improved while the distance between the light receiving element 104 and the optical element 103 is controlled to be 10 μm.

As described above, in the solid-state imaging device 10 according to the present embodiment, the cover glass 101 including the optical element 105, the spacer 106 formed on the cover glass 101 and having a thickness of 10 μm or less, the image sensor chip 102, and the cover glass 101. Are joined by a very small amount of UV curable resin or thermosetting resin dropped on the spacer 106.
In this case, the spacer material is not limited to the photosensitive organic resin, but may be a thin film obtained by depositing a metal material or an inorganic material such as Si, SiO2, or SiN by sputtering or CVD. The target thickness can be accurately made up to about 10 μm.
Further, in the conventional thermocompression bonding of a photosensitive organic material, the cover glass 101 and the image sensor 102 do not have sufficient bonding strength, so that reinforcement with a resin is necessary in a subsequent process.
In contrast, in the manufacturing method of the present embodiment, a very small amount of UV curable resin or heat is previously formed on the thin film spacer 106 having a thickness of 10 μm or less formed on the cover glass 101 provided with the optical element 105. Since the curable resin is dropped and pressure-bonded to the sensor chip, the bonding strength is enhanced and the reinforcement in the subsequent process is not required, so that the manufacturing process can be simplified and the material cost can be reduced.

FIG. 3 is a cross-sectional view of a solid-state imaging device according to the second embodiment of the present invention. The same parts as those in the solid-state imaging device shown in FIG.
In the solid-state imaging device 20 illustrated in FIG. 3, the output of the light receiving element 104 is different from the back surface of the substrate 100, that is, the substrate surface on which the light receiving element 104 is formed, by the through electrode 109 formed on the substrate 100 of the image sensor chip 102. It is configured to be taken out from the surface.
3, the electrode 109 is formed on the substrate surface of the substrate 100 as compared with the case where the output of the light receiving element 104 is extracted from the substrate surface (upper surface) of the substrate 100 as illustrated in FIG. 1. Since the spacer 106 can be bonded to the substrate 100 of the image sensor chip 102 because it is not on the side, the bonding area between the cover glass 101 and the image sensor chip 102 is increased. For this reason, the bonding force between the cover glass 101 and the image sensor chip 102 can be further increased.
Further, even if the resin for forming the adhesive layer 107 is increased to some extent and spreads at the time of pressure bonding, since there is a distance to the light receiving region of the image sensor chip 102, it is difficult for the resin to penetrate into the light receiving region.
Therefore, in the solid-state imaging device 20 configured as described above, it is possible to reduce the risk of degrading the light condensing performance of the microlens 103 and the optical performance of the optical element 104.

4A and 4B are cross-sectional views of the solid-state imaging device according to the third embodiment of the present invention. FIG. 4A is a cross-sectional view showing the structure on the cover glass 101 side, and FIG. 4B is a cross-sectional view of the solid-state imaging device. is there. The same parts as those in the solid-state imaging device shown in FIG.
The solid-state imaging device 30 shown in FIG. 4 has a spacer 106 formed on the cover glass 101 side in an uneven shape as shown in FIG.
The amount of the UV curable resin or thermosetting resin that is the material of the adhesive layer 108 varies depending on the surrounding environment because the characteristics of the resin, such as viscosity, vary.
However, as shown in FIG. 4, by forming grooves 121 in the spacer 106 of the solid-state imaging device 30 and making the surface of the spacer 106 uneven, excess resin material can escape to the groove 121 portion of the spacer 106. Therefore, it is possible to prevent the resin from protruding on the light receiving region or the electrode 109. Further, when the shape of the spacer 106 is formed, the uneven shape can be formed only by changing the pattern of the photomask, so that there is an advantage that the spacer shape can be changed without increasing the number of steps.

FIG. 5 is a cross-sectional view of a solid-state imaging device according to a fourth embodiment of the present invention, where (a) is a cross-sectional view showing the structure on the cover glass 101 side, and (b) is a cross-sectional view of the solid-state imaging device. . The same parts as those in the solid-state imaging device shown in FIG.
The solid-state imaging device 40 shown in FIG. 5 has a groove 131 formed not only on the spacer 106 formed on the cover glass 101 but also on the cover glass 101 as shown in FIG.
With this configuration, the number of steps for etching the glass increases, but more resin can be released using the groove 131.
Further, when the groove 131 is formed close to the upper surface of the cover glass 101 and a black resin is used for the adhesive layer 108, the black light that forms the adhesive layer 108 filled in the groove 131 with light incident from the side surface of the cover glass 101. Since it can be blocked by resin, the function of reducing noise can be obtained without producing a light shielding wall in a separate process.

  10 20 30 40 ... Solid-state imaging device, 100 ... Substrate, 101 ... Cover glass, 102 ... Image sensor chip, 103 ... Microlens, 104 ... Light receiving element, 105 ... Optical element, 106 ... Spacer, 107 ... Protective layer, 108 ... Adhesive layer, 109 ... electrode, 121 131 ... groove

JP 2007-188909 A

Claims (9)

A light receiving element, an electrode for outputting a signal output from the light receiving element to the outside, an image sensor chip having the light receiving element and a substrate supporting the electrode on one surface, and a micro formed on the light receiving surface of the light receiving element A lens, a cover glass disposed opposite to the light receiving surface of the light receiving element and having an optical element formed on a surface facing the light receiving element, and the substrate and the cover glass on the outer diameter side of the light receiving element; And a joint portion for joining between
The bonding portion is a spacer for gap control between the cover glass and the light receiving element fixed to the cover glass surface and bonded to the substrate, and an adhesive layer for bonding the spacer and the substrate, A solid-state imaging device comprising:   The solid-state imaging device according to claim 1, wherein the spacer has a thickness of 10 μm or less.   The solid-state imaging device according to claim 1, wherein the adhesive layer is 1 μm or less.   The solid-state imaging device according to claim 1, wherein the adhesive layer is a UV curable resin or a thermosetting resin.   The joint is made of the same material as the microlens, includes a protective layer fixed to one surface of the substrate, and the adhesive layer is formed between the spacer and the protective layer. The solid-state imaging device according to any one of claims 1 to 4.   The solid-state imaging device according to any one of claims 1 to 5, wherein the electrode is formed on a surface different from a substrate surface on which the light receiving element is formed.   The solid-state imaging device according to any one of claims 1 to 6, wherein a groove is formed on a surface of the spacer.   The solid-state imaging device according to claim 1, wherein a groove is formed from a surface of the spacer to an inside of the cover glass. It is a manufacturing method of the solid-state imaging device according to claim 1,
Depositing or applying a material of the optical element on the cover glass;
Patterning the material to form an optical element having desired optical properties;
Depositing or applying a spacer material on the cover glass to form a spacer material layer of a desired thickness;
Removing the spacer material layer and patterning it into a desired shape;
A step of dripping a trace amount of UV curable resin or thermosetting resin on the spacer formed by patterning the spacer material layer;
After aligning and crimping the cover glass to the image sensor chip, curing the UV curable resin or the thermosetting resin to form the adhesive layer;
A method for manufacturing a solid-state imaging device, comprising:

Images