JPH0269965A - Semiconductor package and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the adherence of a lead frame to a package and to improve workability by forming a premolded housing of thermoplastic resin and sealing its outer groove with a thermosetting sealing material. CONSTITUTION:A housing 1 has an outer wall 3 higher than an inner wall 2 on the inner periphery and a flowing wall 4 lower than the wall 2 on the inner periphery of the wall 2. An outer groove 6 is formed between the walls 2 and 3, and an inner groove 7 is formed between the walls 2 and 4. In the housing 1, a lead frame 5 is integrally formed of thermoplastic resin. A semiconductor element 10 is placed in the housing, and connected by the frame 5 and bonding wires 11. Then, a cover 13 is provided on the top of the wall 2. Thereafter, the wall 2 and the cover are temporarily applied with an adhesive or the like, a thermoplastic sealing material 12 is transfer molded to seal the groove 6, and the top of the groove 6 is sealed with the cover 13 with the material 12.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a hollow thermoplastic resin semiconductor package that has excellent moisture resistance and processability and is suitable for mounting highly integrated large-sized elements. Regarding.

(Prior Art) In recent years, the element density of semiconductor devices has increased, and in terms of memory storage capacity, the degree of integration will continue to increase to 16 megabits and 64 megabits, and there is a tendency for pellets to become larger. As shown in FIG. 5, the method of encapsulating a semiconductor using an epoxy resin encapsulating material, which is currently widely used, involves wire bonding a semiconductor element 20 and lead terminals 21, and then encapsulating them with a encapsulating material 22. Alternatively, as shown in FIG. 6, a pre-molded package λ is made by integrally molding the lead frame 21 with thermoplastic resin, and after the semiconductor element 20 is mounted, it is sealed with the sealing material 22. The M24 was used, but both are approaching their limits. Therefore, in the future, it is thought that hollow-type or gas-sealed semiconductor packages will be used, in which the elements are not directly sealed with resin, in order to be suitable for mounting highly integrated devices and also to be used for image pickup devices. Various types of this type have been developed in the past, but none have been satisfactory.

(Problems to be Solved by the Invention) Ceramic packages have conventionally been used as hollow packages, but they are very expensive and are not economical for memories etc. that are produced in large quantities. In contrast, there are pre-molded packages made of synthetic resin, but each has its own drawbacks. That is, those made of thermosetting resin have the disadvantage of a cap that generates flakes during package molding, causing resin fogging of the leads. Furthermore, although those made of thermoplastic resin are excellent in terms of high productivity, they have drawbacks such as poor adhesion between the lead frame and the thermoplastic resin, and damage to the semiconductor element due to infiltration of moisture such as moisture.

The present invention has been made in view of these circumstances, and has good adhesion between the lead frame and the package, has excellent moisture resistance, and is highly reliable without damaging semiconductor elements.
The present invention also aims to provide an inexpensive semiconductor package with good processability and productivity, and a method for manufacturing the same.

[Structure of the Invention] (Means for Solving the Problems) As a result of intensive research aimed at achieving the above object, the present inventors have discovered that thermoplastic resins have good processability, high productivity, and thermosetting properties. The present invention was completed based on the discovery that the above object can be achieved by combining the excellent adhesiveness of a plastic resin and adopting an excellent structure as a package.

That is, the semiconductor package of the present invention is a package in which a semiconductor element pellet is mounted inside, which is integrated with a lead frame, and has an inner shell, an outer shell provided on the outer periphery of the inner shell higher than the inner shell, and an inner and outer shell. A pre-molded casing made of thermoplastic resin having an outer groove between which the leads of the lead frame are exposed across; and a lid whose outer edge contacts the inner lining of the casing without protruding into the outer groove of the casing, forming a hollow interior of the package. The package is characterized by comprising a mold sealing part made of a thermosetting resin that fills at least the inside of the outer groove of the casing with a mold, and fixes the lid to the casing to airtightly seal the inside of the package. Furthermore, the manufacturing method for semiconductor packages is to mount a semiconductor element pellet in the center of a pre-molded thermoplastic resin housing, place a lid on the upper part of the inner wall of the housing, and then mold the housing with the lid on. It is characterized in that it is inserted into a mold cavity and a mold sealing portion is formed in the outer groove of the casing and the upper part of the outer groove with a thermosetting sealant.

The lead frame used in the present invention includes 42 alloy,
Examples include those using copper alloy or copper-clad laminate as the material.

Examples of the thermoplastic resin used in the present invention include polybutylene terephthalate, polyphenylene sulfide, liquid crystal polymer, polyetherimide, polyamide, etc.
These can be used alone or in combination. This thermoplastic resin forms the resin part of the housing, and is usually formed by injection molding.

Examples of the thermosetting sealing material to be filled in the outer groove of the present invention include epoxy resins and polyimide resins, and these may be used alone or in combination of two or more.

The lid on the inner shell used in the present invention is not particularly limited and may be a thermoplastic resin or metal plate, or a transparent glass plate. When a transparent glass plate or the like is used, it can be used as a semiconductor package for an image sensor.

When molding with a thermosetting encapsulant, in order to prevent the thermosetting encapsulant from penetrating into the hollow interior of the package, adhesive may be used to bond the lid and inner shell, or an elastic backing may be used. may be provided. In addition, molding of thermosetting resin encapsulant is
After mounting the semiconductor element and putting a lid on the upper part of the inner shell, the package is inserted into a mold and molded by injection molding, I/transfer molding, compression molding, etc.

(Function) By providing an outer groove between the inner shell and the outer shell and sealing the thermosetting sealant, it improves the adhesion between the lead frame and the thermoplastic resin package, and also improves the adhesion between the lead terminal side and the inner shell upper lid side. It is possible to prevent the infiltration of moisture from the inside and protect the semiconductor elements.

In addition, by providing an inner groove and a flow stop, even if the thermosetting sealant flows out, the flow is prevented by the flow stop and remains in the inner groove.
There is no adverse effect on semiconductor elements.

(Example) Next, the present invention will be explained using the drawings.

FIG. 1(a) is a front view of the pre-molded casing of the example, FIG. 1(b) is a sectional view taken along the line X-X of FIG. 1(a), and FIG. It is a sectional view along the YY line of figure (a).

In Fig. 1, on the outer periphery of the inner shell 2, there is an outer shell 3 that is higher than the inner shell 2, and on the inner periphery of the inner shell 2 there is a flow stop shell 4 that is lower than the inner shell 2.
It is a provision. There is an outer groove 6 between the inner shell 2 and the outer shell 3, and the outer groove 6 in the direction perpendicular to the lead frame 5 in the front view is a portion 6a that opens at the bottom and exposes the lead frame 5 across (the first In FIG. 1B), the parallel outer groove 6 of the lead frame 5 in the front view is a portion 6b that does not need to be opened all the way to the bottom (FIG. 1C). Furthermore, an inner groove 7 is formed between the inner shell 2 and the stop shell 4. Furthermore, the center of the housing 1 is concave to the lead frame surface, exposing the element mounting portion and the bonding portion of the leads.
This housing 1 is integrally formed with a lead frame 5 made of thermoplastic resin.

Next, the manufacturing process of the semiconductor package of the present invention will be explained using FIGS. 2 to 4.

FIG. 2(a) is a front view showing a state in which a semiconductor element is mounted on a housing, which is one of the components, and wire bonded. FIG. 2(C) is a sectional view taken along the Y-Y line in FIG. 2(a). As shown in FIG. 2(a) to FIG. 2(C), A semiconductor element 10 is mounted on a casing and connected to a lead frame 5 by a bonding wire 11.

Thereafter, as shown in FIGS. 3(a) to 3(C), M13 is provided on the upper part of the inner shell 2. This indigo may be a plastic plate, a metal plate, or a transparent glass plate, and is not particularly limited. By covering it with a transparent lid such as a glass plate or acrylic plate, it can be used as a semiconductor package for an image sensor. It is possible to temporarily attach an adhesive or an elastic backing between the inner shell 2 and the lid 13 to prevent the thermosetting sealant molded into the outer groove from entering. Further, even if the thermosetting sealant should infiltrate, the inner groove 7 and the outflow portion 4 will prevent the infiltration. A sectional view of the mold 14 in which the inner shell 2 is covered with the lid 13 and the casing is inserted is shown in FIG.
In b) - is indicated by a dashed dotted line.

Note that 15 is a sprue. FIGS. 4(a) to 4(c) are a front view and a sectional view showing a semiconductor package of the present invention. In the state shown in FIG. 3(b), the thermosetting sealant 12 is transfer-molded from the sprue 15 to seal the outer groove, and at the same time the upper part of the outer groove is covered with the thermosetting sealant 1.
It is possible to manufacture a semiconductor package in which the package 13 is completely sealed by molding in step 2, and the inside of the package is hollow.

[Effects of the Invention] As is clear from the above description, the semiconductor package of the present invention includes a pre-mode casing with a specific structure that is easily molded by injection molding of thermoplastic resin, and the outer groove of the pre-mode casing is sealed with thermosetting resin. By sealing with an encapsulant, we have improved the adhesion between the thermoplastic resin and the lead frame, so it has excellent moisture resistance and prevents moisture from entering, eliminating damage to the semiconductor element and making it easier to process. Because it has excellent performance and productivity, it is possible to obtain inexpensive and highly reliable semiconductor packages.

[Brief explanation of the drawing]

FIG. 1(a) is a front view of the casing in the embodiment of the present invention;
Figure 1(b) is a sectional view taken along line X-X in Figure 1<a), Figure 1(c) is a sectional view taken along line Y-Y in Figure 1(a), Figure 4 shows the manufacturing process of a semiconductor package which is an embodiment of the present invention.
) is a front view, Principality (b) and (C) are cross-sectional views taken along line X-X and YY of division (a), respectively, and FIGS. 5 and 6 are cross-sectional views of the conventional package. 1.23... Housing, 2... Inner shell, 3... Outer shell, 4... Stop shell, 5.21... Lead frame,
6...Outer groove, 7...Inner groove, 10.20...
・Semiconductor element, 11...bonding wire 1
．． 2.22... Thermosetting sealant, 13... Lid,
14... Mold, 15... Sprue Patent applicant Toshiba Chemical Corporation

Claims (1)

[Scope of Claims] A package in which one semiconductor element pellet is mounted inside, which is integrated with a lead frame and includes an inner shell, an outer shell provided on the outer periphery of the inner shell higher than the inner shell, and between the inner and outer shells. A pre-molded housing made of thermoplastic resin having an outer groove through which the leads of the lead frame are exposed across; a lid whose outer edge contacts the inside of the housing without protruding into the outer groove of the housing to form a hollow interior of the package; A semiconductor package comprising a thermosetting resin mold sealing part that fills the outside groove of the housing with a mold and fixes a lid to the housing to airtightly seal the inside of the package. 2. In manufacturing the semiconductor package according to claim 1, after mounting a semiconductor element pellet in the center of the interior of a pre-molded thermoplastic resin housing, a lid is placed on the upper part of the inner wall of the housing, and then the housing with the lid is placed. 1. A method for manufacturing a semiconductor package, which comprises placing the package into a mold cavity and forming a mold sealing part in the outer groove of the housing and the upper part of the outer groove with a thermosetting sealant.