JPH06151902A - Solid-state imaging device - Google Patents

Abstract

(57) [Abstract] [Purpose] The expansion stress exerted on the semiconductor chip by the adhesive is suppressed to prevent image distortion. [Structure] A circular recess 8 smaller than the outer dimensions of the semiconductor chip 3 is provided on a substrate surface 2 of a ceramic package 1 to which the semiconductor chip 3 is die-bonded, and the semiconductor chip 3 is die-bonded with an adhesive 4 thereon. Then, the semiconductor chip 3 and the bonding lead 7 are connected by the metal wire 5, and the ceramic package 1 is covered with the sealing glass 6 with the adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device.

[0002]

2. Description of the Related Art A solid-state image pickup device is required to have a flat substrate surface in order to prevent defocus due to the inclination of a chip with respect to a reference plane of a package and to improve adhesiveness. The conventional solid-state imaging device will be described below. FIG. 3 is a general assembly sectional view of a conventional solid-state imaging device. In FIG. 3, 1 is a ceramic package and 2 is a semiconductor chip 3.
A substrate surface for die-bonding 4 is an adhesive, 5 is a metal wire, 6 is sealing glass with an adhesive, and 7 is a bonding lead.

In this conventional method of assembling a solid-state image pickup device, first, a semiconductor chip 3 is bonded to a substrate surface 2 of a ceramic package 1 with an adhesive 4 dropped on the substrate surface 2. The adhesive 4 used here is generally thermosetting. next,
Semiconductor chip 3 and bonding lead 7 with metal wire 5
Connect. As a result, the ceramic package 1 and the semiconductor chip 3 are electrically connected. Then, the ceramic package 1 is sealed with the sealing glass 6 with an adhesive. The adhesive of the sealing glass 6 with an adhesive used here is also a thermosetting adhesive.

[0004]

SUMMARY OF THE INVENTION In the above conventional configuration,
Since the substrate surface 2 of the ceramic package 1 has a flat structure, the stress in the pushing-up direction acts from the adhesive 4 to the semiconductor chip 3 during the assembly by the subsequent heat treatment including heat curing after the semiconductor chip 3 is bonded. To do. That is, first, the semiconductor chip 3 is adhered to the ceramic package 1 with the adhesive 4. However, when the adhesive is hardened thereafter, thermal expansion of the adhesive 4 causes a stress in the pushing direction to act on the semiconductor chip 3. Next, also in the wire bonding, the stress acts on the semiconductor chip 3 from the adhesive 4 if the heating method is used. Finally, also when the sealing glass 6 with adhesive is thermally cured, the same stress acts on the semiconductor chip 3 from the adhesive 4. In addition, in the heat treatment after the semiconductor chip 3 is bonded to the ceramic package 1 with the adhesive 4, the stress acts on the semiconductor chip 3 from the adhesive 4. The stress in the push-up direction that acts on the semiconductor chip 3 due to the thermal expansion of the adhesive 4 causes distortion on the surface of the semiconductor chip 3, causing crystal defects of the semiconductor chip 3 and an image distortion phenomenon peculiar to the solid-state imaging device. There was a problem.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a solid-state image pickup device which suppresses the expansion stress exerted on the semiconductor chip by the adhesive and does not cause image distortion.

[0006]

In order to achieve this object, a solid-state image pickup device according to the present invention is provided with a recess smaller than the outer dimension of the semiconductor chip on a substrate surface of a package for die-bonding the semiconductor chip, and an adhesive on the recess. The semiconductor chip is die-bonded by.

[0007]

According to the structure of the present invention, a stress is generated by the expansion of the adhesive when the adhesive is heat-cured, etc. Since it is absorbed in the dents, it is possible to suppress the expansion stress exerted on the semiconductor chip by the adhesive and prevent the surface of the semiconductor chip from being distorted.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a general assembly sectional view of a solid-state imaging device according to an embodiment of the present invention. In FIG. 1, 1 is a ceramic package, 2 is a substrate surface on which a semiconductor chip 3 is die-bonded, 4 is an adhesive agent for adhering the semiconductor chip 3 and the ceramic package 1, 5 is a metal wire, 6 is a sealing glass with an adhesive agent, 7 Is a bonding lead, 8 is a substrate surface 2
It is a round recess made in. Note that FIG. 2 is a perspective view of the ceramic package 1.

In this solid-state image pickup device, a circular recess 8 smaller than the outer dimensions of the semiconductor chip 3 is provided on the substrate surface 2 of the ceramic package 1 for die-bonding the semiconductor chip 3.
The semiconductor chip 3 is die-bonded thereon with the adhesive 4. Then, the semiconductor chip 3 and the bonding lead 7 are connected by the metal wire 5, and the ceramic package 1 is covered with the sealing glass 6 with the adhesive.

The operation at the time of assembling the solid-state image pickup device configured as described above will be described. First, the adhesive 4 is filled in the recess 8 provided in the substrate surface 2 of the ceramic package 1. The semiconductor chip 3 is placed there. At that time, the adhesive 4 protrudes from the round recess 8 provided on the substrate surface 2, but the semiconductor chip 3 is positionally regulated by the recess 8 provided on the substrate surface 2 and the edge portion of the substrate surface 2. Therefore, the focus shift due to the inclination of the semiconductor chip 3 can be made to the conventional level.

Next, the adhesive 4 is cured by heat treatment. At that time, the semiconductor chip 3 due to the thermal expansion of the adhesive 4
The stress acting in the upward direction acting on the semiconductor chip 3 is absorbed in the round recess 8 provided in the substrate surface 2, and the stress does not directly act on the semiconductor chip 3. Similarly, in the subsequent assembly, the adhesive 4
The stress in the pushing-up direction exerted on the semiconductor chip 3 due to the thermal expansion is absorbed in the round recess 8 provided on the substrate surface 2, and the stress does not directly act on the semiconductor chip 3.

As described above, according to this embodiment, the recess 8 smaller than the outer dimension of the semiconductor chip 3 is provided on the substrate surface 2 of the ceramic package 1, and the semiconductor chip 3 is die-bonded thereon with the adhesive 4. Since the stress generated by the expansion of the adhesive 4 at the time of heat curing of the adhesive 4 is absorbed in the recess 8, the expansion stress exerted on the semiconductor chip 3 by the adhesive 4 is suppressed, and the surface of the semiconductor chip 3 is suppressed. It is possible to prevent the occurrence of distortion, and it is possible to realize an excellent solid-state imaging device in which image distortion does not occur. The depth of the recess 8 is determined by obtaining the amount of strain on the chip surface in the case of a conventional flat substrate surface and setting the depth at which it can be eliminated.

In this embodiment, the recess 8 provided on the substrate surface 2 is round, but it may be square instead of round. However, in the case of a square type as well, it is set smaller than the external dimensions of the semiconductor chip 3.

[0014]

As described above, according to the present invention, the recesses smaller than the outer dimensions of the semiconductor chip are provided on the substrate surface of the package, and the semiconductor chip is die-bonded thereon with the adhesive, so that the adhesive is thermally cured. Since the stress generated by the expansion of the adhesive in is absorbed in the recess, it is possible to suppress the expansion stress exerted on the semiconductor chip by the adhesive, it is possible to prevent the surface of the semiconductor chip from being distorted,
It is possible to realize an excellent solid-state imaging device in which image distortion does not occur.

[Brief description of drawings]

FIG. 1 is a general assembly sectional view of a solid-state imaging device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a ceramic package of a solid-state image pickup device according to an embodiment of the present invention.

FIG. 3 is a general assembly sectional view of a conventional solid-state imaging device.

[Explanation of symbols]

 1 Ceramic Package 2 Board Surface 3 Semiconductor Chip 4 Adhesive 8 Recess

Claims (1)

[Claims] 1. A solid-state imaging device in which a semiconductor chip is die-bonded to a substrate surface of a package with an adhesive, wherein a recess smaller than an outer dimension of the semiconductor chip is provided on a substrate surface of the package to which the semiconductor chip is die-bonded. A characteristic solid-state imaging device.