JPH03225867A - solid state imaging device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid-state imaging device that converts optical signals into electrical signals.

[Prior Art] A solid-state imaging device is a device that electrically reads the amount of light that reaches a large number of regularly arranged photoelectric conversion elements (photodiodes), and is used in VTR cameras, copying machines, and the like.

A solid-state imaging device mainly consists of the following components. In other words, a solid-state imaging chip has a light-receiving part made up of a large number of photodiodes, a package for holding the solid-state imaging chip and leads, and a plurality of chips from the side of the package for electrically connecting the solid-state stone image chip to the outside. A protruding lead, a light receiving window provided on the top surface of the package to capture light into the solid-state imaging chip, and a light transmittance that is bonded to the top surface of the package with a sealant to cover the light receiving window, and a light transmittance for capturing light into the light receiving section. It is a glass cap made of high quality material.

The electrodes and leads of the solid-state imaging chip are connected with bonding wires. Each of the multiple leads extends horizontally from the side of the package, and is bent downward at almost right angles to the top surface of the package a little beyond the lead.

Regarding solid-state imaging devices, for example, see Video Information 25-3 published by Japan Industrial Development Corporation on May 1, 1986.
It is written on page 1.

[Problems to be Solved by the Invention] Conventional sealants for bonding a glass cap to a package in order to cover the light-receiving window of the package have been white or transparent. Therefore, there is a problem in that the incident light is diffusely reflected during imaging, resulting in flare defects.

An object of the present invention is to provide a solid-state imaging device that can suppress flare due to diffuse reflection of incident light.

[Means for Solving the Problems] In order to solve the above problems, a solid-state imaging device of the present invention includes a solid-state imaging chip placed in a package, electrically connected to an electrode of the solid-state imaging chip, A plurality of leads for external connection protrude from the side surface of the package, a light receiving window provided in the package to take in light to the solid-state imaging chip, and a light receiving window provided on the package to cover the light receiving window, which is bonded to the package with a sealant to cover the light receiving window. and a glass cap, and the sealant is gray, black, or colored.

[Effect]

In the solid-state imaging device of the present invention, since the color of the sealant is gray, black, or a chromatic color, diffuse reflection of incident light can be prevented and flare can be suppressed.

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

DVC is a solid-state imaging device, PKG is a black package made of ceramic, CHI is a solid-state imaging chip, LD is a lead for electrically connecting the solid-state imaging chip CHI and an external application circuit, and WIR is an electrode of the solid-state imaging chip CHI. A bonding wire made of Al for connecting the lead LD and the AGP connects the solid-state imaging chip CHI to the package P.
Ag paste for die bonding on KG, W
DW is a light receiving window provided on the top surface of package PGK to take in light to the solid-state imaging chip CHI, and GLS is light receiving window W.
The glass cap SM bonded to the top surface of the package PKG to cover DW is a gray organic sealant for bonding the glass cap GLS to the package PKG and sealing the light receiving window WDW. Although not shown, on the surface of the solid-state imaging chip CHI, photodiodes for converting optical signals into electrical signals are arranged two-dimensionally, and each photodiode separates light into red, green, and blue. Organic color filters are directly formed.

Since the color of the sealant SM is gray, flare due to diffuse reflection of light at the sealant part can be reduced.

The color of the sealant SM should be black other than gray, or a chromatic color that matches the color of the package.

It is desirable that the color of the sealant SM be close to the color of the package PKG, and that the brightness of the sealant SM be lower than the brightness of the package PKG.

In addition, when adhering and sealing the glass cap GLS to the package PKG via the sealant SM, the thickness of the sealing layer (hereinafter referred to as sealing thickness) is on the order of 10 μm, so the excess sealant that is not sealed is Since the sealant protrudes to the side of the glass cap GLS, unevenness (thickness unevenness) is formed in the sealant.

By using similar colors, the unevenness in the thickness of the sealant SM is less noticeable, which is desirable in terms of appearance, and by changing the brightness, the unevenness in the thickness of the sealant can be seen from the contrast.

Table 1 is a table showing the specifications of an example of a sealant according to the present invention and an example of a conventional sealant in comparison.

Margin below.

Table 1 In this example, in order to make the sealant SM gray,
0.1wt% (0.05-0.15wt%) of black pigment C (carbon black) and 35wt% (30-40w
t%) of white filler ZnO (zinc white) was mixed.

With such a composition, it was possible to create a color that is easy to distinguish from the appearance in order to detect color unevenness for the purpose of controlling the seal portion, which is important for maintaining moisture resistance. Furthermore, in order to maintain the moisture resistance of solid-state imaging devices, we optimized the additive of the silane coupling agent (0.5 wt%), which is an interfacial modifier that minimizes the moisture permeation rate in the epoxy resin. planned.

The color of the sealant after sealing is determined by the light transmittance of the sealant, and the magnitude of the transmittance is mainly determined by the amounts of filler and pigment added and the sealed portion. In a normal seal, increasing the amount of white filler increases the reflection of incident light at the seal, and conversely, decreasing the amount of filler or increasing the amount of pigment increases the absorption rate of transmitted light. To increase. Also, if the amount of filler and pigment added is constant, the color of the seal part is determined by the seal part, and if the seal part is different, the color of the seal part is determined by the seal part.
The reflectance of incident light at the seal portion changes, and thereby products with abnormal seal thickness, that is, products with defective sealing are detected.

Further, while the conventional white sealant changed color to yellowish brown during curing, the sealant of this example did not change color.

As described above, in the solid-state imaging device DVC of this embodiment, since the color of the organic sealant SM is gray, it is possible to reduce flare caused by diffused reflection of light at the white sealant portion as in the conventional device. In addition, by setting the color of the sealant SN1 to the same gray color as the black of the package PKG, it is possible to detect thickness unevenness based on the difference in contrast, and it also makes the thickness unevenness less noticeable. It provides a sense of experience and improves the appearance.

FIG. 2 is a flowchart showing an example of the assembly process of the solid-state imaging device of this embodiment.

First, prepare a glass cap, solid-state imaging chip, package, and sealant. Glass caps are sorted by monitor and laser sorted. A solid-state imaging chip is attached to a package, bonded with Al, and cleaned before sealing. Next, the organic sealant paste according to the present invention is applied to the package and pre-cured to remove gas from the paste. Next, a glass cap is crimped and sealed onto the package to complete the package. In this process, since no sealant is applied to the glass cap before sealing, the entire surface of the cap can be cleaned to remove foreign matter adhering to the cap.

Note that the package may be sealed by pressing a glass cap coated with the organic sealant according to the present invention onto the package.

FIGS. 3(a) to 3(e) are diagrams showing the structure of a solid-state imaging device according to another embodiment of the present invention.Hereinafter, the entire structure will be described as solid-state imaging device DVC1 excluding solid-state imaging chip CHI. The part (container) is called package PKG.

In the same figure, (a) shows the solid-state imaging device DVC connected to the chip C.
FIG. 3 is a top view when viewed from the light-receiving surface side of the HI. Top view (
Based on a), (b) is a side view when viewed from above, (c) is a sectional view taken along the C-C cutting line, (d) is a side view when viewed from the right side, and (e) is a side view when viewed from the right side. It is a sectional view taken along the e-C cutting line.

The glass cap GLS is a translucent sealing plate and is made of a glass material such as borosilicate glass (B, O, .S i O,). The glass cap GLS is coated with a gray organic sealant S on the top surface of the package PKG to cover the light receiving window WDW.
It is attached by M.

The solid-state imaging chip CHI is made using monolithic semiconductor integrated circuit technology, and a plurality of photoelectric conversion elements such as photodiodes are arranged on the surface (light receiving surface) on the glass cap GLS side, and an adhesive such as silver paste material is arranged on the back surface. It is bonded to the lower ceramic substrate LOW using an adhesive.

The black lower ceramic substrate LOW has a chip mount part MNT, which is a recess for mounting the solid-state imaging chip CHI, in the center thereof, and the height relationship between the solid-state imaging chip CHI and the internal leads IL is adjusted by this recess. Ru.

The black upper ceramic frame UPP has a light receiving gwDw cut out in the center so that external light hits the solid-state imaging chip CHI.

The lead LD is a lead for electrically connecting between the solid-state imaging chip CHI and an external application circuit such as a printed wiring board, and a frit glass (low melting point glass) FLT is connected between the upper and lower ceramic bodies UPP and LOW. It is fixed in place. The lead LD has an internal lead portion IL for connection to the solid-state imaging chip CHI and an external lead portion OL for connection to an external circuit, and both lead portions are formed continuously (integrated). The 16 internal leads IL have the same tip shape and are located in the middle, and the 4 internal leads ILI have a round hole in the center, have a thick tip shape, and are located in the 4 corners. There are a total of 20 internal leads IL2. This special shape of the internal lead IL2 is useful for lead position pattern recognition during automatic wire bonding.

The bonding wire WIR is a metal wire made of A1, Au, or the like for electrically connecting the internal lead IL and the bonding pad of the solid-state imaging chip CHI.

Due to the recess in the chip mount part MNT, the upper surface of the solid-state imaging chip CHI is located at a lower position than the upper surface of the internal lead IL, so the bonding wire WIR hangs down and comes into contact with the edge of the solid-state imaging chip CHI, causing a short circuit. It can be prevented.

Reference holes HLI and HL2 are formed in the metal plates REF1 and REF2. When the solid M&image chip CHI is automatically die-bonded to the chip mounting part MNT, its positioning is performed based on the reference holes HLI, HL2 and/or the internal leads IL2, so the reference holes HL1. The relative positions of HL2 and solid-state imaging chip CHI are set with high precision. Therefore, the solid-state imaging device DVS
If the reference holes HLI and HL2 are used as positioning standards when mounting the semiconductor device on an applied product, the center of the lens of the applied product and the center of the photodiode array of the solid-state imaging chip CHI can be aligned with high precision.

The recess IDX is a recess provided in the upper and lower ceramic bodies UPP and LOW, and is an index indicating the circuit arrangement reference position of the 20 external leads ILL. This index IDX also serves as a means to prevent incorrect connections by placing a bottle or the like that fits into the recess of the index IDX on the printed circuit board side when inserting the solid-state imaging device DVS (external lead OL) into the printed circuit board. .

In the solid-state imaging device DVC of this embodiment, the organic sealant S
Since the colors of k and I are gray, diffuse reflection of incident light can be prevented and flare can be suppressed. Furthermore, since there is a contrast between the organic sealant SM and the package PKG, it is possible to detect uneven thickness of the sealant. Furthermore, organic sealant S
Since M and package PKG have similar colors, the appearance is improved.

Next, a method for assembling the solid-state imaging device DVS will be briefly described.

First, lead LD and metal plate for reference hole REF 1, REF
A lead frame in which two parts are connected is formed from a single metal plate by press molding or etching. As the metal material, for example, 42 alloy (an alloy with a weight ratio of Ni: 42% and Fe: 58%), which is compatible with ceramics, is selected.

Next, the lead frame with the external leads OL bent in the vertical direction is placed on the lower ceramic substrate LOW, which has frit glass FLT coated in a frame shape on the high part around the chip mount part MNT, and is sandwiched between the upper ceramic frame TJPP. , and fuse them using frit glass FLT.

Next, attach the solid-state imaging chip CHI to the chip mount section MNT.
Then, automatic wire bonding is performed between the internal lead IL and the solid-state imaging chip CHI using a bonding wire WIR.

Next, attach the glass cap GLS to the upper ceramic frame UP.
Paste on P with gray organic sealant SM.

Finally, cut off the unnecessary parts of the lead frame, and remove the 20 internal leads IL and the reference Okawa metal plates REF 1 and REF 2.
Separate each of them. The convex portions BRD of the reference metal plates REF1 and REF2 shown in the top view of (a) are the remains of unnecessary bridge portions removed.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above embodiments, and it goes without saying that various changes can be made without departing from the spirit of the invention.

[Effects of the Invention] As described above, the solid-state imaging device of the present invention can suppress flare due to scattering of incident light during imaging.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a solid-state imaging device according to an embodiment of the present invention;
FIG. 2 is a flowchart showing an example of the assembly process of the solid-state imaging device of this embodiment, and FIGS. 3(a) to 3(e) are diagrams showing a solid-state imaging device of another embodiment of the present invention. (a) is a top view of the solid-state imaging device, (b) is a side view when viewed from above (a), (c) is a cross-sectional view taken along the line C-C in (a), (d) is (a) ) as seen from the right side, (
e) is a sectional view taken along the line e-C in (a). DVC...Solid-state imaging device PKG...Package CHI...Solid-state imaging chip LD...Lead WIR...Bonding wire AGP...Ag paste WDW...Light receiving window GLS...Glass cap S M ... Organic sealant LOW ... Lower ceramic substrate Li N T ... Chip mount part FLT ... Frit glass OL ... External lead IL ... Internal lead RE F l, REF2 ... Reference chamber Metal plate for HLI,
2...Positioning reference hole BRD...Bridge cut remaining portion UPP...Upper ceramic frame IDX...Index and reverse insertion prevention part. Figure 1 DVC...Solid-state imaging device SN...Organic sealant

Claims (1)

[Claims] 1. A solid-state imaging chip placed in a package, a plurality of leads for external connection that are electrically connected to the electrodes of the solid-state imaging chip and protrude from the side of the package, and light is taken into the solid-state imaging chip. a light-receiving window provided in the package to cover the light-receiving window; and a glass cap bonded to the package with a sealant to cover the light-receiving window, and the sealant is gray, black, or colored. Characteristic solid-state imaging device.