JPH08236684A - Manufacture of lead frame and semiconductor employing it - Google Patents

Abstract

PURPOSE: To eliminate the gap by previously applying a thermoplastic tape to a pad and punching the thermoplastic tape and the pad simultaneously thereby ensuring the positional accuracy between the tape for bonding an IC chip and a pad through hole. CONSTITUTION: A thermoplastic tape 3 and a pad are punched simultaneously such that a predetermined shape is obtained without limiting to one direction on the surface and rear thus preventing the positional shift between a through hole 4 of the thermoplastic tape 3 and a through hole 2 of the pad 1. Consequently, peel off of an IC chip and cracking of package can be prevented. Furthermore, sealing material is fed through the through hole 2 of the pad 1 at the time of packaging thus bonding the pad 1 and the IC chip 5 rigidly. With such structure, sufficient durability can be held even when the pad 1 is subjected to thermal stress.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lead frame having a semiconductor chip mounting portion having a predetermined through hole, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Generally, a semiconductor device (IC) is mounted on an IC chip mounting portion (hereinafter referred to as a pad) of a lead frame.
The C chip is fixedly mounted, each electrode of the IC chip and the corresponding inner lead part are connected by a bonding wire, and the inside of the inner lead is packaged with a sealing material such as resin or ceramic, and the outer lead protruding from the package. Is molded into a desired shape.

However, in the semiconductor device having the above-mentioned structure, the thermal expansion coefficient is different depending on each material such as the IC chip, the lead frame and the sealing resin, so that the thermal stress applied during the die bonding process or mounting on the substrate causes Peeling occurs at the material interface between the IC chip and the pad, or the pad and the sealing resin, which significantly reduces the reliability of the semiconductor device.

[0004] In recent years, as IC chips have become more highly integrated and the size of IC chips has increased, on the other hand, there has been a demand for downsizing and thinning of the entire semiconductor package, and the occurrence of the above problems has become more prominent. .

For this reason, conventionally, for example, by providing through holes or slits at several positions in the pad portion of the lead frame, the pad has a strain releasability to relieve thermal stress, and the interface between the IC chip and the pad is reduced. A method for preventing peeling has been proposed, and a certain action and effect are recognized for the above-mentioned problems.

[0006]

FIG. 3 shows an example in which a thermoplastic tape is used for fixing an IC chip to a pad having a predetermined through hole. Conventionally, the through hole 2 of the pad 1 and the through hole 4 of the thermoplastic tape 3 are punched separately, and then the through hole 2 of the pad 1 is formed.
Further, the through holes 4 of the thermoplastic tape 3 were aligned and bonded so that the hole shape and the hole size were the same.
However, in the pasting, it is difficult to accurately align the pad through hole 2 and the thermoplastic tape through hole 4 with each other, so that a slight deviation occurs in the pasting position. A gap 10 is generated between the pad 5 and the pad 1 due to the difference between the pad through hole 2 and the thermoplastic tape through hole 4. The gap 10 is a minute region, and when the sealing resin is injected for packaging, the sealing resin cannot enter the region of the gap 10 and becomes a residual bubble. Therefore, air bubbles expand during heating and pressurization and IC
This is a cause of chip peeling or cracking of the package.

As another IC chip fixing method, a method of fixing the IC chip to the pad by thermosetting using a paste material has been proposed. However, the IC chip is fixed to the pad by heat and pressure during the die bonding process. There is a problem that gas is generated and a foaming phenomenon occurs, and the IC chip moves in an irregular direction from the mounting position of the pad, which is not preferable. From the above, the conventional technique cannot ensure sufficient reliability of the semiconductor device. In the present invention, in order to solve the problems described above, it is possible to secure the positional accuracy of the tape for fixing the IC chip and the pad through hole, and to provide a method for manufacturing a lead frame without the above gap, and a semiconductor device using the same. With the goal.

[0008]

To achieve the above object, the present invention is characterized in that a tape-like adhesive material such as a thermoplastic tape whose outer diameter has been removed is attached to a pad in advance. Then, there is a method of manufacturing a lead frame having a pad shape having a predetermined through hole by simultaneously punching out the tape-shaped adhesive material and the pad, and a semiconductor device using the same.

[0009]

In the present invention, since the tape-shaped adhesive material, which has only the outer diameter removed in advance, is attached to the pad and punched simultaneously, the pad through-hole size and the tape through-hole size are exactly the same. Therefore, it is possible to prevent the formation of a gap portion that becomes a bubble.

Since it is possible to prevent the formation of the gap portion, it is possible to completely fill the sealing resin, and therefore, the IC chip and the pad, the peeling at the interface between the pad and the sealing resin, the package crack, and the like caused by air bubbles do not occur.

Further, since the adhesiveness between the encapsulating material that has entered the pad through hole, the pad, and the IC chip is improved, it is possible to maintain a strong state against deformation of the pad due to thermal stress. Greatly improves the reliability of the device.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged view of a pad portion of a lead frame according to the present invention. The material of the lead frame is iron nickel or copper.

Although 1 is a pad and 2 is a through hole of the pad, the present invention is not limited to the predetermined number and shape of the through holes, and the number and shape can be arbitrary. The through holes relieve the stress and heat stress applied to the pad. In addition, it is useful, for example, to improve the adhesiveness with the sealing material.

Reference numeral 3 denotes a tape-shaped adhesive such as a thermoplastic tape or a thermosetting tape, and it is preferable that the outer diameter of the thermoplastic or thermosetting tape is outside the end of the IC chip size.

Further, in the present invention, the thermoplastic tape 3 and the pad 1 are not limited to one direction of the front and back sides, but are punched at the same time to obtain a predetermined shape, so that the through hole 4 of the thermoplastic tape 3 is formed. Since there is no deviation between the position and the position of the through hole 2 of the pad 1, peeling of the IC chip, cracking of the package, etc. do not occur.

During packaging, the sealing material enters through the through holes 2 of the pad and firmly adheres the pad 1 and the IC chip 5 to each other, so that the stress applied to the pad 1 due to thermal stress. It has sufficient durability against occurrence.

FIG. 2 shows a semiconductor device according to the present invention,
The circuit terminal of the IC chip 5 and the tips of the inner leads 6 provided on the outer periphery of the pad 1 are connected by a thin metal wire 7 for the purpose of electrical conduction. Reference numeral 8 denotes a semiconductor device package according to the present invention, which includes the pad 1 on which the IC chip 5 is fixedly held and the inner lead 6
The inside is packaged with a sealing material such as resin or ceramic, and the outer leads 9 protruding from the package 8 are molded into a desired shape.

[0018]

As described above, according to the present invention, it is possible to provide a thin and highly reliable semiconductor device having a high density by preventing the unfilled portion of the sealing material in the package from being generated. Is possible.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view of a pad portion of a lead frame according to an embodiment of the present invention.

FIG. 2 is a sectional view of a semiconductor device according to an embodiment of the present invention.

FIG. 3 is a sectional view of a semiconductor device showing a conventional technique.

[Explanation of symbols]

 1, pad 2, pad hole 3, thermoplastic tape 4, thermoplastic tape hole 5, IC chip 6, inner lead 7, bonding wire 8, package 9, outer lead 10, air bubble

Claims (2)

[Claims] 1. A tape-shaped (thermoplastic) adhesive material for fixing a semiconductor chip and a semiconductor chip mounting portion to the semiconductor chip mounting portion in advance, and the (thermoplastic) adhesive material and the semiconductor chip mounting portion. A method of manufacturing a lead frame including a semiconductor chip mounting portion having a predetermined through hole by punching the same at the same time. 2. A semiconductor chip mounting portion, in which a through-hole having a predetermined shape is punched and formed simultaneously with a tape-shaped adhesive material adhered, the semiconductor chip is fixedly mounted via the adhesive material, and the semiconductor chip and the semiconductor are mounted. A semiconductor device in which an inner lead provided on the outer periphery of a chip mounting portion is connected by a bonding wire, and the inside of the inner lead is packaged with a sealing material.