JP2016063003A - Solid-state imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state imaging device that is easily manufactured and that can reduce a package size.SOLUTION: A solid-state imaging device comprises: a substrate; a solid-state imaging substrate on whose front surface a photosensitive part on which a plurality of photoelectric conversion elements are arranged in a row and a peripheral circuit part arranged so as to surround the photosensitive part, are provided, and to whose rear face side the substrate is adhered; a connection conductor for connecting a pad on the substrate and a pad on the solid-state imaging substrate; a spacer adhered onto the solid-state imaging substrate so as to expose a surface of the photosensitive part; and a transparent base material adhered on the spacer so as to cover a predetermined region including the surface of the photosensitive part. An inner end surface of the spacer is adhered onto the peripheral circuit on the surface of the solid-state imaging substrate. An outer end surface of the spacer is arranged outside from a pad position on the substrate.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a solid-state imaging device.

  Along with the advancement and development of semiconductor integrated circuit technology, the number of pixels of solid-state imaging devices such as CMOS (Complementary Metal Oxide Silicon) sensors and CCDs (Charged Coupled Devices) tends to increase. In addition, along with a decrease in the price of solid-state imaging devices, there is an increasing demand for solid-state imaging devices having a large area such as a full size or an APS-C size for the purpose of improving sensitivity. In the solid-state imaging device, a package having a structure for sealing the surface of the photosensitive part is necessary so that dust or the like does not adhere to the photosensitive part in which a plurality of photoelectric conversion elements are arranged.

  The larger the photosensitive area, the larger the package size, making it difficult to mount on various electronic devices that are becoming lighter and thinner.

For this reason, proposals have been made to reduce the size of the package, but in general, if the size of the package is reduced, heat tends to be trapped inside, and problems such as the solid-state imaging substrate on which the photosensitive portion is formed may be warped. There is.
Even if the package size is reduced, if the manufacturing is not easy, the yield does not increase and the cost of the solid-state imaging device cannot be reduced.

JP 2013-4534 A

  The problem to be solved by the present invention is to provide a solid-state imaging device that is easy to manufacture and can be reduced in package size.

According to this embodiment, a substrate;
A solid-state imaging substrate in which a photosensitive portion in which a plurality of photoelectric conversion elements are arranged and a peripheral circuit portion disposed so as to surround the photosensitive portion are provided on the front surface, and the substrate is bonded to the back surface side;
A connection conductor connecting the pad on the substrate and the pad on the solid-state imaging substrate;
A spacer bonded to the solid-state imaging substrate so that the surface of the photosensitive portion is exposed;
A transparent base material adhered on the spacer so as to cover a predetermined region including the surface of the photosensitive part,
An inner end face of the spacer is bonded onto the peripheral circuit on the surface of the solid-state imaging substrate, and a solid-state imaging device is provided in which an outer end face of the spacer is disposed outside a pad position on the substrate.

1 is a perspective view of a solid-state imaging device 1 according to the present embodiment. The longitudinal direction (XX direction) sectional drawing of FIG. Sectional drawing of the solid-state imaging device 1 using the spacer 5 by one modification. The figure which the human finger touched the spacer 5. FIG. (A) is a perspective view which shows the manufacturing process of the solid-state imaging device 1, (b) is sectional drawing. (A) And (b) is the perspective view and sectional drawing following FIG. (A) And (b) is the perspective view and sectional drawing following FIG. (A) And (b) is the perspective view and sectional drawing following FIG. (A) And (b) is the perspective view and sectional drawing following FIG. (A) And (b) is the perspective view and sectional drawing following FIG. (A) And (b) is the perspective view and sectional drawing following FIG. FIG. 3 is a plan view in which an adhesive 12 is attached on the solid-state imaging substrate 3 with a gap. (A) is a figure which shows the dimension of the solid-state imaging device 1, (b) is a figure which shows the dimension of various optical sizes.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The vertical direction in the following embodiments indicates a relative direction when the surface on which the solid-state imaging device is provided is upward, and may be different from the vertical direction according to the gravitational acceleration.

  1 is a perspective view of a solid-state imaging device 1 according to the present embodiment, and FIG. 2 is a longitudinal sectional view (XX direction) of FIG. The solid-state imaging device 1 according to the present embodiment is, for example, a CMOS sensor or a CCD covered with a package.

  A solid-state imaging device 1 in FIG. 1 includes a dielectric substrate 2, a solid-state imaging substrate 3, a connection conductor 4, a spacer 5, and a transparent base material 6. Among these, the constituent members of the package include the dielectric substrate 2, the spacer 5, and the transparent base material 6.

  The dielectric substrate 2 is a ceramic substrate with excellent heat dissipation, for example. On the surface of the dielectric substrate 2, pads 11 for connecting the bonding wires 4 as the connection conductors 4 and a wiring pattern (not shown) connected to the pads 11 are arranged. The pads 11 are arranged at the edge of the surface of the dielectric substrate 2. On the back surface of the dielectric substrate 2, pads (not shown) and terminals for mounting on a printed wiring board (not shown) are arranged. The front surface side pads 11 and the wiring pattern and the back surface side pads are electrically connected through, for example, contacts (not shown).

  On the surface of the solid-state imaging substrate 3, a photosensitive portion 8 in which a plurality of photoelectric conversion elements are arranged, and a peripheral circuit portion 9 disposed so as to surround the photosensitive portion 8 are disposed. In addition, pads 7 for connecting the bonding wires 4 are arranged in a row at the edge of the surface of the solid-state imaging substrate 3. Furthermore, the back surface of the solid-state imaging substrate 3 is bonded to the dielectric substrate 2 via an adhesive 21.

  Each photoelectric conversion element in the photosensitive unit 8 is, for example, a photodiode 13. In addition, the photosensitive unit 8 includes a color filter 14 and a micro lens 15 in association with each photodiode 13. A photodiode 13 is disposed on the semiconductor layer, a color filter 14 is disposed above the photodiode 13, and a microlens 15 is disposed further thereon. As described above, the photosensitive portion 8 is provided with the photodiode 13, the color filter 14, and the microlens 15 for each pixel, and the surface of the photosensitive portion 8 is provided with a plurality of pixels vertically and horizontally.

  The peripheral circuit unit 9 includes a shift register that transfers the electric signal photoelectrically converted by the photodiode 13, an amplifier that amplifies the electric signal after transfer, an A / D converter that converts the amplified electric signal into a digital signal, and the like. It is out.

  The bonding wire 4 as the connection conductor 4 connects the pad 11 on the dielectric substrate 2 and the pad 7 on the solid-state imaging substrate 3. These pads 7 and 11 and the bonding wire 4 are made of a material having excellent conductivity (for example, gold).

  The spacer 5 is bonded to the solid-state imaging substrate 3 so that the surface of the photosensitive portion 8 is exposed. For the spacer 5, an insulator such as resin or ceramic is used. As shown in the cross-sectional view of FIG. 2, the inner end face 5 a of the spacer 5 is arranged in the arrangement area of the peripheral circuit portion 9, and the outer end face 5 b of the spacer 5 is arranged outside the position of the pad 11 on the dielectric substrate 2. ing. In this specification, the center side of each substrate surface of the dielectric substrate 2 and the solid-state imaging substrate 3 is referred to as an inner side, and the end portion side of each substrate surface is referred to as an outer side. The inner end surface 5 a is a surface that is located on the innermost side of the spacer 5 and is bonded to the solid-state imaging substrate 3. Further, the outer end surface 5 b in FIG. 2 is a surface that is located on the outermost side of the spacer 5 and is bonded to the dielectric substrate 2.

  In the example of FIG. 2, the inner end surface 5 a of the spacer 5 is bonded to the surface of the peripheral circuit portion 9, and the outer end surface 5 b of the spacer 5 is the surface of the dielectric substrate 2 outside the position of the pad 11 on the dielectric substrate 2. It is glued to. However, as will be described later, it is not always necessary to bond the outer end surface 5b of the spacer 5 to the dielectric substrate 2, and the outer end surface 5b of the spacer 5 is disposed outside the position of the pad 11 on the dielectric substrate 2. It only has to be. However, it is an essential requirement of the present embodiment that the inner end surface 5a of the spacer 5 is bonded to the solid-state imaging substrate 3 within the arrangement region of the peripheral circuit portion 9.

  In the example of FIG. 2, the spacer 5 is a frame body 5 having an opening larger than the area of the photosensitive portion 8, and is positioned so that the entire surface of the photosensitive portion 8 is exposed from the opening. The inner end surface 5 a of the frame 5 is bonded to the solid-state imaging substrate 3 on the peripheral circuit unit 9. The outer end surface 5 b of the frame body 5 is disposed outside the position of the pad 11 on the dielectric substrate 2 and bonded to the dielectric substrate 2. The reason why the inner end surface 5a of the frame body 5 is bonded to the solid-state imaging substrate 3 on the peripheral circuit portion 9 is that it does not hinder imaging even if the frame body 5 is bonded to the surface of the peripheral circuit portion 9. Further, if the inner end surface 5a of the frame 5 is bonded outside the peripheral circuit portion 9, the outer dimensions of the spacer 5 may increase. Therefore, in the present embodiment, the inner end surface 5 a of the spacer 5 is bonded to the solid-state imaging substrate 3 on the peripheral circuit portion 9.

  The frame 5 is bonded to the solid-state imaging substrate 3 and the dielectric substrate 2 so as to straddle the bonding wires 4. Therefore, the bonding wire 4 can be covered with the frame body 5, and it is possible to prevent the bonding wire 4 from being disconnected due to an external impact or from adhering moisture or the like to the bonding wire 4. If the bonding wire 4 is exposed, a manufacturing process such as hardening the bonding wire 4 with a resin is required, and workability is poor, and an operation for finding an optimal resin is also required, resulting in an increase in manufacturing cost and manufacturing throughput. There is a risk of lowering. On the other hand, if the bonding wire 4 is covered with the frame 5 as shown in FIG. 2, the work of hardening the bonding wire 4 with resin becomes unnecessary and the workability is improved.

  As described above, the frame-shaped spacer 5 is supported by the solid-state imaging substrate 3 by the inner end surface 5a. Since the spacer 5 is stably supported by this, the spacer 5 is used for the purpose of increasing the support strength. 5 does not need to be bonded to the dielectric substrate 2. The advantage of adhering the outer end surface 5b of the spacer 5 to the dielectric substrate 2 is that the bonding wire 4 can be covered with the spacer 5 to prevent the bonding wire 4 from being exposed. As a result, as described above, the bonding wire 4 can be protected, and the work of fixing the bonding wire 4 with resin or the like is not required.

  Thus, since the support of the spacer 5 is basically performed by the inner end surface 5 a of the spacer 5, the contact area of the inner end surface 5 a of the spacer 5 with the solid-state imaging substrate 3 is the dielectric substrate 2 on the outer end surface 5 b of the spacer 5. It is desirable to make it larger than the contact area. That is, since the adhesion between the outer end surface 5b of the spacer 5 and the dielectric substrate 2 does not need to improve the support strength, it is desirable to reduce the contact area as much as possible to suppress the outer size of the spacer 5.

  The outer shape of the spacer 5 is not necessarily limited to that shown in FIGS. For example, FIG. 3 is a cross-sectional view of the solid-state imaging device 1 using the spacer 5 according to a modification. In the spacer 5 of FIG. 3, the inner end surface 5a is bonded to the solid-state imaging substrate 3 as in FIG. 2, but the outer end surface 5b of the spacer 5 is not bonded to the dielectric substrate 2, and the dielectric substrate. 2 is arranged to float above 2. However, the outer end face 5 b of the spacer 5 in FIG. 3 is arranged outside the position of the pad 11 on the dielectric substrate 2. This means that the outer end surface 5 b of the spacer 5 is located outside the bonding wire 4. Therefore, as shown in FIG. 4, even when a human finger 20 touches the upper surface of the spacer 5, the finger can be prevented from touching the bonding wire 4. Thereby, the deformation | transformation and disconnection of the bonding wire 4 can be prevented.

  Further, the spacer 5 of FIG. 3 has a U-shaped cross section like the spacer 5 of FIG. 1, and a part of the bonding wire 4 is covered with the spacer 5. As a result, the gap between the outer end surface 5b of the spacer 5 and the dielectric substrate 2 is reduced, and the possibility that foreign matters such as dust adhere to the bonding wire 4 is reduced.

  Thus, the outer end surface 5b of the spacer 5 according to the present embodiment only needs to be disposed outside the position of the pad 11 on the dielectric substrate 2, and the spacer 5 needs to be supported by the outer end surface 5b of the spacer 5. Therefore, the area of the outer end face 5b can be reduced compared to the structure in which the spacer 5 is supported on the dielectric substrate 2 outside the position of the pad 11 on the dielectric substrate 2, and as a result, the outer shape of the spacer 5 can be reduced. The package size can be reduced.

  5-11 is a figure which shows the manufacturing process of the solid-state imaging device 1 by this embodiment. (A) of each figure of FIGS. 5-11 is a perspective view, (b) is a longitudinal cross-sectional view. Hereinafter, the manufacturing process will be described based on these drawings.

  First, as shown in FIGS. 5A and 5B, a thermosetting adhesive 21 is applied to the upper surface of the dielectric substrate 2. The adhesive 21 is applied, for example, in a strip shape with an interval substantially parallel to the short side direction of the dielectric substrate 2. There are no particular restrictions on the width and number of the bands of the adhesive 21.

  Next, as shown in FIG. 6A, the back surface side of the solid-state imaging substrate 3 is brought into contact with the applied adhesive 21 and adhered to the dielectric substrate 2 in a state where the solid-state imaging substrate 3 is positioned. The adhesive 21 is cured by heating to a temperature of. Thereby, the solid-state imaging substrate 3 is fixed to the dielectric substrate 2 via the adhesive 21, and the solid-state imaging substrate 3 and the dielectric substrate 2 have a thickness of the adhesive 21 as shown in FIG. It will be spaced apart by that amount. Thereby, a ventilation hole can be provided between the solid-state imaging substrate 3 and the dielectric substrate 2, and the heat dissipation of the solid-state imaging substrate 3 is improved.

  Next, as shown in FIGS. 7A and 7B, the pads 7 on the solid-state imaging substrate 3 and the pads 11 on the dielectric substrate 2 are connected by bonding wires 4. In the example of FIG. 7, the bonding wires 4 are connected only at both ends in the longitudinal direction on both substrates 2 and 3, but the bonding wires 4 are also connected at both ends in the short direction on both substrates 2 and 3. May be performed.

  Next, as shown in FIGS. 8A and 8B, a thermosetting adhesive 12 for bonding the spacer 5 is applied in the region of the peripheral circuit portion 9 on the solid-state imaging substrate 3. . In the example of FIG. 8A, the adhesive 12 is applied not only to the solid-state imaging substrate 3 but also to the pads 11 on the dielectric substrate 2, but this application operation may be omitted. Below, the example which applies the adhesive agent 12 for spacer 5 adhesion on both the board | substrates 2 and 3 is demonstrated.

  The adhesive 12 may be applied in a rectangular shape with a certain width without a gap, or may be provided with a gap where the adhesive 12 is not applied in places as shown in the plan view of FIG. If the gap is provided, when the spacer 5 is bonded to the solid-state imaging substrate 3 via the adhesive 12, the air between the frame 5 and the solid-state imaging substrate 3 can be pushed out through the gap, and the air pressure Can be lowered. Therefore, even if heat is applied to cure the adhesive 12, the air pressure accumulated between the frame 5 and the solid-state imaging substrate 3 suddenly rises and the inconvenience such as separation of the bonded portion does not occur. .

  Next, as shown in FIGS. 9A and 9B, the spacer 5 is positioned, the inner end surface 5a of the spacer 5 is brought into contact with the adhesive 12, and the inner end surface 5a of the spacer 5 is solid-state imaged. While adhering on the board | substrate 3, the outer side end surface 5b of the spacer 5 is made to contact the adhesive agent 12, the outer side end surface 5b of the spacer 5 is adhere | attached on the dielectric substrate 2, and the adhesive agent 12 is hardened by applying heat.

  Next, as shown in FIGS. 10A and 10B, a thermosetting adhesive 22 for adhering the transparent base material 6 to be a lid is applied to the upper surface of the spacer 5. This adhesive 12 may also be applied with a gap as shown in FIG. 10A, or may be continuously applied in a rectangular shape without a gap.

  Next, as shown in FIGS. 11 (a) and 11 (b), the transparent substrate 6 is positioned and adhered to the upper surface of the spacer 5 via the adhesive 22, and heat is applied to the adhesive 22. Harden. As described above, the solid-state imaging device 1 shown in FIG. 1 is completed.

  The solid-state imaging device 1 according to the present embodiment can be applied to the photosensitive unit 8 having various optical sizes. As shown in FIG. 13A, the optical size of the photosensitive portion 8 is substantially standardized by the ratio of the horizontal length H and the vertical length V of the photosensitive portion 8. FIG. 13B shows an example of a standardized optical size. FIG. 13B shows a full size of the same size as a 35 mm film, an APS-C of the same size as a film of an APS camera, Four Thirds, 1/1 inch, 2/3 inch, 1 / 1.7 inch, 1 A horizontal length H and a vertical length V of 1/2 inch, 1 / 2.33 inch, and 1 / 2.3 inch are described.

  As shown in FIG. 13, the solid-state imaging device 1 according to the present embodiment can be applied to any photosensitive unit 8 having a different size. Further, the present invention can also be applied to the photosensitive portion 8 having an optical size other than that shown in FIG.

  As described above, in this embodiment, the inner end face 5a of the spacer 5 is bonded to the peripheral circuit portion 9 on the surface of the solid-state imaging substrate 3, and the outer end face 5b of the spacer 5 is placed outside the position of the pad 11 on the dielectric substrate 2. Therefore, the bonding wire 4 can be protected by the spacer 5 while reducing the outer dimension of the spacer 5. In particular, in the present embodiment, the inner end face 5a of the spacer 5 can be adhered to an arbitrary position on the peripheral circuit portion 9 on the surface of the solid-state imaging substrate 3, so that the peripheral circuit portion 9 can be obtained even if the optical size of the photosensitive portion 8 is different. The size of the inner end surface 5a of the spacer 5 may be determined according to the size of the spacer 5, and the peripheral circuit portion 9 has a certain width, so that the dimension design of the spacer 5 is facilitated.

  Further, if the outer end surface 5b of the spacer 5 is bonded to the dielectric substrate 2, the bonding wire 4 can be covered with the spacer 5, and the work of fixing the bonding wire 4 with a resin or the like becomes unnecessary. It can be protected and workability is improved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Solid-state imaging device, 2 Dielectric substrate, 3 Solid-state imaging substrate, 4 Connection conductor, 5 Spacer, 6 Transparent base material, 7 Pad, 10 Bonding wire, 11 Pad, 12 Adhesive, 13 Photodiode, 14 Color filter, 15 Microlens, 20 fingers, 21,22 Adhesive

Claims (5)

A substrate,
A solid-state imaging substrate in which a photosensitive portion in which a plurality of photoelectric conversion elements are arranged and a peripheral circuit portion disposed so as to surround the photosensitive portion are provided on the front surface, and the substrate is bonded to the back surface side;
A connection conductor connecting the pad on the substrate and the pad on the solid-state imaging substrate;
A spacer bonded to the solid-state imaging substrate so that the surface of the photosensitive portion is exposed;
A transparent base material adhered on the spacer so as to cover a predetermined region including the surface of the photosensitive part,
A solid-state imaging device in which an inner end surface of the spacer is bonded onto the peripheral circuit on the surface of the solid-state imaging substrate, and an outer end surface of the spacer is disposed outside a pad position on the substrate.   2. The solid-state imaging device according to claim 1, wherein an outer end surface of the spacer is bonded to a surface of the substrate outside a pad position on the substrate.   The solid-state imaging device according to claim 2, wherein an adhesion area between the inner end surface of the spacer and the solid-state imaging substrate is wider than an adhesion area between the outer end surface of the spacer and the substrate. The spacer is a frame having an opening that exposes the photosensitive portion,
The inner end surface of the frame is bonded onto the peripheral circuit on the surface of the solid-state imaging substrate, the outer end surface of the frame is bonded to the surface of the substrate outside the pad position on the substrate, and the connection conductor The solid-state imaging device according to claim 1, which is covered with the frame.   The solid-state imaging device according to claim 1, wherein an outer end surface of the spacer is disposed above a surface of the substrate.

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