JP2001085652A - Infrared ccd image pick up element package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output a clearer blur-free image. SOLUTION: The package 30 comprises a silicon chip 18 bonded to the die attach face 34 on the bottom of a black package housing 32 through black colored die bonding adhesive 36. The silicon chip 18 has an image sensor 20 mounted on the upper surface thereof. Two leads 22 project outward from the side wall of the package housing 32 and then bend downward. A glass plate 24 transparent for infrared rays is provided on the package housing 32 while covering the silicon chip 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared ray CCD image pickup device package, and more particularly to an infrared ray CCD image pickup device package having a clear captured image.

[0002]

2. Description of the Related Art CCD camera (CCD image sensor)
Is a camera using a CCD image pickup device package as an image pickup device, which is composed of an image pickup unit for performing photoelectric conversion and a transfer unit for performing scanning, and extracts an image signal using an analog shift register. An infrared CCD camera is a camera that captures an image with light emitted from an infrared lamp as a light source, and includes an infrared CCD image sensor package.

Here, referring to FIG. 3, an infrared CCD is used.
Conventional general infrared C with imaging device package
The configuration of the CD imaging device package will be described. FIG. 3 is a sectional view showing the configuration of a conventional infrared CCD image pickup device package. Conventional infrared CCD image sensor package 1
Reference numeral 0 (hereinafter simply referred to as a package 10) is a package in which an infrared CCD image pickup device used for an infrared CCD camera is packaged. As shown in FIG. And a package housing 12 having a die attach surface 14 at the bottom of the accommodation chamber 19.
The back surface of the silicon chip 18 is adhered to the die attach surface 14 with the die bonding adhesive 16, and the silicon chip 18 is held in the storage chamber 19 of the package housing 12. The two leads 22 are connected to the package housing 1.
2 protrudes outward from the side wall and then bends downward. Furthermore, a glass plate 24 transparent to infrared rays
It is provided on the package housing 12 so as to cover the silicon chip 18. In the conventional package 10, the housing 12 is formed of ceramic, and a silver paste is used as the adhesive 16 for die bonding.

[0004]

However, the image picked up by the conventional infrared CCD camera has a problem in terms of sharpness, and there is a problem that the image picked up has a circular cloud. Accordingly, an object of the present invention is to provide an infrared CCD image sensor package capable of outputting a clearer and less cloudy image than an output image of a conventional infrared CCD image sensor package.

[0005]

The present inventor first investigated the cause of the occurrence of circular fogging in a captured image, and found the following. Since silicon transmits infrared light, a part of the infrared light incident on the package 10 is
To reach the die bonding adhesive 16 on the back surface of the silicon chip and the die attach surface 14 of the housing 12. Part of the infrared rays that have arrived are reflected by the die bonding adhesive 16 and the die attach surface 14 and directed upward, incident on the image pickup device 20 of the silicon chip 18, and the image pickup device 20 receives the reflected light to form a CCD. Was found to affect the output image.

Further studies have shown that die bonding adhesive 16
When a silver paste, which is most commonly used, is used, the silver paste is usually applied in a spot form, so that the die bonding adhesive layer 16 made of the silver paste is bonded to the silicon paste as shown in FIG. Instead of uniformly and uniformly spreading over the entire back surface of the chip 18, a region 26 having a high silver paste distribution density, a region 27 having a low silver paste distribution density, and a region 28 having no silver paste distribution are formed. . Therefore, the regions 26, 27, and 2 where the silver paste distribution density differs.
5, the distribution pattern of the silver paste layer 16 was reflected in the output image of the CCD, and the image was blurred, as shown in FIG.

Therefore, the present inventor has proposed that a housing made of a material having a low reflectance for infrared rays is used, and a die bonding adhesive having a low reflectance for infrared rays is used. The idea of suppressing the generation of reflected return light by coating the film with an infrared transmission preventing film was repeated, and experiments were repeated to complete the present invention.

To achieve the above object, based on the knowledge obtained, an infrared CCD imaging device package according to the present invention comprises a silicon chip having an imaging device on an upper surface and a package housing having a die attach surface on a bottom portion. Body, and the back surface of the silicon chip is bonded to the die attach surface with an adhesive, wherein at least the die attach surface of the package housing is formed of a material having a low reflectance with respect to infrared rays. The silicon chip is characterized in that the back surface of the silicon chip is bonded to the die attach surface of the package housing with an adhesive having a low reflectance for infrared rays.

The type and composition of the adhesive used in the present invention are not limited as long as the adhesive can bond the silicon chip onto the die attach surface and has low reflectance to infrared rays. For example, by using an adhesive that exhibits a black color by mixing a black pigment, the adhesive has a low reflectance with respect to infrared rays. In order to form at least the die attach surface of the package housing with a material having a low reflectance with respect to infrared rays, each of the package housings is formed of a plastic material or a ceramic material exhibiting black by mixing a black pigment.

In the present invention, since at least the die attach surface of the package housing and the adhesive have low reflectance with respect to infrared rays, the infrared rays that have passed through the silicon chip and reached the adhesive, and the infrared rays that have passed through the silicon chip, are transmitted. Or the infrared light that has reached the die attach surface without passing through the silicon chip is absorbed by the adhesive and the die attach surface, respectively, and reflects only a small amount of infrared light, so that the amount of return light is extremely small. Therefore, unlike the conventional case, the distribution pattern of the adhesive layer does not appear in the output image, and the image does not blur due to the infrared rays returned from the die attach surface.

In a preferred embodiment of the present invention, an infrared transmission preventing film is coated on the back surface of the silicon chip bonded to the die attach surface with an adhesive. Examples of the infrared transmission prevention film include a metal plating film such as a gold plating film, a silver plating film, and a copper plating film. In the present embodiment, the transmitted light transmitted through the silicon chip is reflected by the infrared transmission preventing film, for example, a gold plating film, and does not reach the adhesive layer. This prevents the image from being blurred by the infrared rays returned from the die attach surface.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment 1 This embodiment is an example of an embodiment of an infrared CCD imaging device package according to the present invention, and FIG. 1 is a cross-sectional view showing a configuration of the infrared CCD imaging device package of this embodiment. is there. In the infrared CCD imaging device package 30 of the present embodiment, as shown in FIG. 1, a package housing 32 is formed of black plastic, which is colored with a black pigment, thereby forming a die attach surface 34.
Is black and shows a low reflectance with respect to infrared rays, and the die bonding adhesive 36 in which the silicon chip 18 is adhered to the die attach surface 34 is colored with a black pigment and has a black color. Except that the adhesive 36 thereby exhibits a low reflectivity for infrared radiation,
It has the same configuration as the conventional infrared CCD image pickup device package 10.

In the present embodiment, since the package housing 32 and the adhesive 36 have low reflectance with respect to infrared rays, the infrared rays that have passed through the silicon chip 18 and reached the adhesive 36 and the silicon chip 18 Infrared rays that have passed through or arrived at the die attach surface 34 without passing through the silicon chip 18 are absorbed by the adhesive 36 and the die attach surface 34, respectively, and only a small amount of infrared light is reflected, and return light and Become. Therefore, the distribution pattern of the adhesive layer is prevented from being reflected in the output image as in the related art, and
The image is not blurred by the infrared rays returned from the die attach surface.

Embodiment 2 This embodiment is another example of the embodiment of the infrared CCD image pickup device package according to the present invention. FIG. 2 shows the configuration of the infrared CCD image pickup device package of this embodiment. FIG. The infrared CCD imaging device package 40 of the first embodiment is the same as the infrared CCD imaging device package of the first embodiment except that a gold plating film 42 having a thickness of 1 μm is provided on the back surface of the silicon chip 18 as an infrared transmission preventing film. It has the same configuration as 30.

In the present embodiment, since the transmitted light transmitted through the silicon chip 18 is reflected by the gold plating film 42 and does not reach the adhesive layer 36, the infrared CCD of the first embodiment is used.
The distribution of the adhesive layer is not further reflected in the output image than in the image pickup device package 30, and the image is not blurred by the infrared rays returned from the die attach surface.

[0016]

According to the present invention, at least the die attach surface of the package housing is formed of a material having a low reflectance to infrared rays, and the silicon chip is bonded to the die attach surface with an adhesive having a low reflectance to infrared rays. Adhesion prevents the distribution of the adhesive layer from being reflected in the output image, as occurs in a conventional infrared CCD image pickup device package, and also prevents the image from being blurred by the infrared rays returned from the die attach surface. Is prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an infrared ray CCD image pickup device package according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a configuration of a CCD imaging device package for infrared rays according to a second embodiment.

FIG. 3 is a cross-sectional view showing a configuration of a conventional infrared CCD image sensor package.

FIG. 4 is a schematic diagram showing a distribution of silver paste.

FIG. 5 is a schematic diagram showing an output image of a CCD imaging device for infrared rays.

[Explanation of symbols]

10: Conventional CCD image sensor package for infrared ray, 1
2 ... package housing, 14 ... die attach surface, 16
…… Die bond adhesive, 18… Silicon chip, 1
9 ... accommodation room, 20 ... image sensor, 22 ... lead, 2
4 ... glass plate, 26 ... area where silver paste distribution density is high, 27 ... area where silver paste distribution density is low, 28
... Area where silver paste is not distributed, 30... The infrared ray CCD image pickup device package of the first embodiment, 32.
Package housing, 34: die attach surface, 36: die bonding adhesive, 40: infrared ray C of the second embodiment
CD imaging device package, 42: gold plated film.

Claims (3)

[Claims] 1. An infrared CCD image pickup device comprising: a silicon chip having an image pickup device on an upper surface; and a package housing having a die attach surface on a bottom portion, wherein the back surface of the silicon chip is adhered to the die attach surface with an adhesive. In the package, at least the die attach surface of the package case is formed of a material having a low reflectivity to infrared rays, and the back surface of the silicon chip is bonded to the die attach surface of the package case with an adhesive having a low reflectivity to infrared rays. An infrared CCD imaging device package, which is adhered to a substrate. 2. A material having a low reflectance with respect to infrared rays is a plastic material having a black color or a ceramic material having a black color, and the adhesive having a low reflectance with respect to the infrared rays is an adhesive colored with a black pigment. 2. The infrared CCD image pickup device package according to claim 1, wherein: 3. The infrared CCD image pickup device package according to claim 1, wherein an infrared transmission preventing film is coated on a back surface of the silicon chip bonded to the die attach surface with an adhesive.