JPH04343457A - Improving method for moisture resistance of solid state image pickup element package and high moisture resistant solid state image pickup device - Google Patents

Abstract

PURPOSE:To improve moisture resistance without almost increasing thickness of a thermosetting resin package of a solid state image pickup device. CONSTITUTION:A package body 1 of thermosetting resin of a solid state image pickup device is so mounted at a jig as to expose only a bottom, and a moisture permeation preventive layer 7 is provided in the bottom of the exposed body 1 by a coating method, a sputtering method, a vapor-depositing method, etc. A laminated ceramic package or a CERDIP package having the same shape and size and equivalent moisture resistance are obtained. Then, productivity can be improved without reducing reliability and its cost can be reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the moisture resistance of a solid-state imaging device package and a highly moisture-resistant solid-state imaging device.

0002

[Background Art] In recent years, solid-state imaging devices (hereinafter abbreviated as CCD) have been widely used in various video cameras, camera-integrated VTRs called movie cameras, and electronic still cameras (still video cameras). In particular, as the popularity of movies increases, CC
Demand for D to be smaller and lower in price is becoming stricter.

Currently, the 1/2 inch CCD or 1/3 inch CCD packages used in movies are laminated ceramic packages or cerdip packages, but from the viewpoint of productivity and cost reduction, thermosetting is used. Plastic mold packages made of synthetic resin are attracting attention.

However, in the case of thermosetting resin plastic mold packages (hereinafter abbreviated as thermosetting resin packages), there is a problem in moisture resistance compared to the conventionally used laminated ceramic packages or cerdip packages. .

[0005] Thermosetting resins have a larger water diffusion coefficient than thermoplastic resins, and the largest amount of moisture infiltrates through the bulk. For thermoset resin packages,
It was found that the predominant route for moisture infiltration is from the bottom of the package, even in the bulk.

[0006] Therefore, in order to improve the moisture resistance of a thermosetting resin package, it is sufficient to prevent moisture from entering from the bottom surface. To achieve this, it is sufficient to increase the thickness of the bottom surface of the package.
By increasing the thickness from m to 1.7 mm, the pressure cooker test at 121°C and 100% relative humidity (
It was confirmed that the average condensation life in PCT2) was extended by about twice.

[0007]

[Problem to be Solved by the Invention] However, if the thickness of the bottom of the package is increased in this way to improve moisture resistance, even if it is 0.7 mm, not only will the design of the package be changed. This is not desirable for CCDs for movies, which have seen significant progress toward miniaturization in recent years.

Therefore, it is impossible to create a highly moisture-resistant package for 1/2 inch CCD or 1/3 inch CCD while maintaining the current thickness using a highly productive and low-cost thermosetting resin. Have difficulty. Moreover, future C
In terms of the direction of CDs, it is predicted that the size will become smaller and smaller as movies become smaller, and the bottom of the package will need to be thinner and thinner. It becomes impossible to increase the moisture resistance effect of the package.

An object of the present invention is to provide a package with improved moisture resistance without substantially increasing the thickness of the bottom surface of the package.

0010

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a method for improving the moisture resistance of a solid-state image sensor package by forming a moisture permeation prevention layer on the bottom surface of the solid-state image sensor package. , and a highly moisture-resistant CCD in which a moisture permeation prevention layer is formed using this method.

[0011]

[Operation] In this invention, by adopting a method for improving moisture resistance of a solid-state image sensor package in which a moisture permeation prevention layer is formed on the bottom surface of a solid-state image sensor package, the moisture permeation prevention layer is formed by this moisture resistance improvement method. Although a high humidity resistant CCD employs a thermosetting resin package, it can have the same shape and size as a multilayer ceramic package or a cerdip package, and can obtain moisture resistance equivalent to that of a multilayer ceramic package or a cerdip package.

0012

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a CCD with improved moisture resistance using the method of forming a moisture permeation prevention layer of the present invention, and FIGS. 2 and 3
1 is a sectional view of a jig for forming a moisture permeation prevention layer only on the bottom surface of a CCD.

In FIG. 1, 1 is a package body made by molding a thermosetting resin, 2 is a CCD chip mounted in a recess provided in the center of the package body 1,
3 is a lead frame, and a bonding wire 4 is connected between the inner lead of the lead frame 3 and the electrode of the CCD chip 2.
The sealing glass 5 is sealed in the recess at the top of the package body 1 with the sealing resin 6.Finally, the outer lead portion of the lead frame 3 is bent as shown in FIG. 1 to form a CCD in a thermosetting resin package. is completed.

As shown in FIG. 2 or 3, the highly moisture-resistant CCD of the present invention has a box-shaped or plate-shaped jig 8 fitted with a jig 8 that matches the size of the package body 1 of the 1/2 inch CCD or 1/3 inch CCD. Hole 9 is provided and lead frame 3
A plurality of pieces are installed in the holes 9 so that only the bottom surface of the package body 1, where the outer lead parts are kept in a straight state before the outer lead parts are bent, is exposed from the jig 8. The package body 1 is made by limiting the portion forming the package body 1 to the bottom surface of the package body 1.

There are four methods for forming the moisture permeation prevention layer 7 on the bottom surface of the package body 1, as described below.

The first method is to attach the package body 1 to the hole 9 of the jig body 8a of the jig 8 shown in FIG. The light-receiving surface of the package body 1 is held by the bonded cushioning material 10 and brought into close contact with the hole 9. Then, an organic silica-based coating material is applied to the bottom of the package body 1.
By coating by dipping, screen printing, gravure printing, or the like, only the bottom surface of the package body 1 is coated. Then, the coated package body 1 is irradiated with ultraviolet rays and/or heated to form an inorganic moisture permeation prevention layer 7 on the bottom surface of the package body 1. This formation method was adopted, and NHC. AT-70
7 or NHC. After dipping AT-720A (manufactured by Nissan Chemical Industries, Ltd.) on the bottom of the package body 1, the package body 1 was irradiated with ultraviolet rays and/or heated.
The moisture resistance of PCT2 was improved from about 1.4 times to 2 times the average dew condensation life.

The second method also involves dipping Teflon-based water-repellent resin onto the package body 1, which is attached to the jig 8 with its bottom face down, as shown in FIG. A moisture permeation prevention layer 7 of an organic film is formed on the bottom surface of the package body 1 by coating and evaporating the solvent contained in the resin at high temperature or room temperature. By adopting this formation method, amorphous Teflon-based TEFLON. The moisture resistance of the package body 1, which was coated with AF resin (manufactured by Du Pont) and the solvent was evaporated, was improved from about 2.3 times to 3 times the average dew condensation life in PCT2.

In the third method, a single metal, two or more metals or alloys, an oxide or composite oxide of a metal, a metal oxide or a composite oxide, or a metal A moisture permeation prevention layer 7 is formed by sputtering carbide, metal nitride, metal boride, metal fluoride, etc. only on the bottom surface of the package body 1.

A fourth method is to use a single metal, two or more metals or alloys, or a CCD mounted on a jig 8 shown in FIG.
A moisture permeation prevention layer 7 is formed by depositing a metal oxide or composite oxide, metal carbide, metal nitride, metal boride, metal fluoride, etc. only on the bottom surface of the package body 1.
form.

The moisture permeation prevention layer 7 according to the third method or the fourth method is formed of the material described below.

Cr, Al, Au, Ag, Mo, Mn, F
Single metals such as e, Zn, Cu, W, Ti, V, Si, Ge, and two or more metals or alloys. SiO2,
SiO, SiON, SnO2, In2O3, Al
2O3, MgO, ITO, ZnO, TiO2, T
Metal oxides or composite oxides such as a2 O5. SiC, TiC, B4C, BC, WC, Al4Si
Metal carbides such as C5, Al8 B4 C7. S
i3 Nitride of metals such as N4, AlN, and BN. T
Metal borides such as iB2 and LaB6. B6S
i, silicides of metals such as FeSi and CrSi. Metal fluorides such as MgF2. Alternatively, combinations and composite compounds of a plurality of these substances can also be used.

In the highly moisture-resistant CCD in which the moisture permeation prevention layer 7 is formed by the four methods described above, the moisture permeation prevention layer 7 is formed only on the bottom surface, and the moisture permeation prevention layer 7 is formed on other parts, especially the outer lead part of the lead frame 3. During soldering, it is possible to avoid the formation of a film that deteriorates solder bonding properties. The outer lead portion of the lead frame 3 is then bent to complete a highly moisture resistant CCD as shown in FIG. The thickness of the moisture permeation prevention layer 7 is from 0.1 μm to 10 μm.
A range of 0 μm is valid.

[0024]

As described above, according to the present invention, there is provided a method for improving the moisture resistance of a solid-state image sensor package in which a moisture permeation prevention layer is formed on the bottom surface of the solid-state image sensor package, and a moisture permeation prevention layer formed by this method. By employing the formed highly moisture-resistant CCD, the increase in the thickness of the bottom surface of the thermosetting resin package can be suppressed to 100 μm or less, making it possible to maintain the CCD package without requiring any design changes. Therefore, it is possible to obtain moisture resistance equivalent to that of a multilayer ceramic package or a cerdip package using a thermosetting resin package that has the same shape and size as a multilayer ceramic package or a cerdip package. It is possible to improve CCD productivity and reduce costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a CCD with improved moisture resistance using the method of forming a moisture permeation prevention layer of the present invention.

FIG. 2 is a sectional view of a first embodiment of a jig used in the method of forming a moisture permeation prevention layer of the present invention.

FIG. 3 is a sectional view of a second embodiment of a jig used in the method of forming a moisture permeation prevention layer of the present invention.

[Explanation of symbols]

1 Package body 2 CCD chip 3 Lead frame 4 Bonding wire 5 Seal glass 6 Seal resin 7 Moisture permeation prevention layer 8 Jig 8a Jig body 8b Jig lid 9 holes 10 Cushion material

Claims (5)

[Claims] 1. A bottom surface of a package for a solid-state image sensor is coated with an organic silica coating material, and then an inorganic moisture permeation prevention layer is formed on the organic silica coating material by irradiating ultraviolet rays and/or heating. A method for improving the moisture resistance of solid-state image sensor packages. 2. A method for improving moisture resistance of a solid-state imaging device package, comprising forming a moisture permeation prevention layer of an organic film on the bottom surface of the solid-state imaging device package by coating a Teflon-based water-repellent resin. . 3. Sputtering a single metal, two or more metals or an alloy on the bottom surface of a package for a solid-state image sensor;
A solid-state image sensor package characterized by forming a moisture permeation prevention layer of metal oxide or composite oxide, metal carbide, metal nitride, metal boride, metal silicide, metal fluoride, etc. How to improve moisture resistance. 4. A single metal, two or more metals or alloys, metal oxides or composite oxides, metal carbides, metal nitrides, and metal borides are deposited on the bottom surface of the solid-state imaging device package by vapor deposition. A method for improving the moisture resistance of a solid-state image sensor package, characterized in that a moisture permeation prevention layer of metal silicide, metal fluoride, or the like is formed. 5. A highly moisture-resistant solid-state imaging device, characterized in that a moisture permeation prevention layer is formed by the method according to claim 1.