JPH06120409A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a fault of lead plating and to reduce a fault of connection to an external device by a method wherein plated surfaces of a plurality of outer leads are protected by an adhesive sheet. CONSTITUTION:After wire bonding is completed, a lead frame 1 is conveyed to a molding process and a chip 4, bonding wires 5, inner leads 6, etc., are sealed in a package 9 formed of thermosetting resin. Subsequently the lead frame 1 is conveyed to an adhesive sheet sticking process. Herein surfaces of outer leads 8 of the lead frame 1 are plated with solder beforehand. Then, the outer leads in a plurality projecting from one side of the package 9 are connected as one unit by sticking thereon an adhesive sheet 10 coated with an adhesive which is set to lose adhesion by application of ultraviolet rays. In this way, the plated surfaces of the leads are protected.

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 semiconductor device, and more particularly to a semiconductor device (hereinafter referred to as an IC) or an outer lead in which an outer lead is plated with a fragile material such as solder plating. The present invention relates to a technique effective when applied to an IC that is easily bent.

[0002]

2. Description of the Related Art An IC is mounted on a board and incorporated in home electric appliances and various external devices for use. However, if the outer lead of the IC is not plated, the surface of the outer lead will be The oxide film on the surface of the outer lead material oxidizes and repels solder for connection used when mounting the IC on an external device,
There is a problem that the outer lead, which cannot properly mount the IC on the substrate, is easily corroded.

For this reason, the outer lead surface is preliminarily plated, and as a method therefor, a method of plating when forming a lead frame and a method of plating a completed IC. There is. However, in order to deal with ICs with complicated lead shapes and ICs with a narrow lead interval recently, the outer lead is provided by electroplating in which the plating thickness can be easily controlled in the lead frame state. There is an increasing number of methods of forming plating on the surface of.

Regarding the manufacturing process of the lead frame, "Guide for Electronic Materials Trading", edited by Gematech Co., 1987.
Published April 18, 2012 p. 199.

[0005]

However, when the plated outer lead is contaminated or scratched by an external factor during the manufacture of the IC, the outer lead is soldered to the external substrate when the IC is soldered. There is a possibility that solder may not be properly deposited on the surface of the lead and a connection failure may occur, or that the plating of the outer lead may be corroded from the peeled portion.

If the outer lead is bent during the transportation of the IC, the outer lead needs to be corrected, the automatic testing cannot be performed, and the external device cannot be surely connected. There's a problem.

Therefore, an object of the present invention is to provide a method of manufacturing a semiconductor device which prevents lead plating defects and reduces connection defects to external devices.

Another object of the present invention is to provide a technique for preventing lead bending during transportation in the manufacturing process of a semiconductor device.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0010]

The outline of the representative ones of the inventions disclosed in the present application will be briefly described as follows.

That is, the plating is applied, and at least a portion of the plating necessary for connecting to an external device is bonded to the adhesive sheet.
The outer cover and the outer lead are connected to each other and attached.

[0012]

By the above means, even if stress is applied to the outer lead due to external impact, the adhesive tape is attached between the outer lead and the outer lead.
Since it is reinforced with a push-pull, it can be prevented from bending.

By covering the surface of the outer lead with a sheet, it is possible to prevent the surface of the outer lead from coming into contact with the outside and peeling off the plating. Furthermore, the plating due to the peeling off of the plating can be prevented. It is intended to prevent defective soldering to an external device from occurring.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic process flow of a method of manufacturing an IC which is an embodiment of the present invention, and FIG. 2 is a manufacturing explanatory view of a lead frame manufactured by the manufacturing method of FIG. As shown in the figure, the chip 4 is mounted after a process of mounting the chips 4 on a plurality of tabs 3 which are located at the substantially central portion of the lead frame 1 and supported by the tab lead 2, that is, a so-called chip bonding process. The prepared lead frames are sequentially moved to the wire bonding step A one by one. Here, the bonding wire 5 connects the electrode formed on the upper surface of the chip 4 and the tip of the inner lead 6 to be electrically connected. For the sake of convenience, the leads will be described by distinguishing them between the inner lead 6 and the outer lead 8 inside and outside the tie bar 7 for convenience. After the wire bonding is completed, the lead frame 1 is conveyed to the molding step B, and the chip 4, the bonding wire 5, the inner lead 6 and the like are packaged 9 made of a thermosetting resin.
Seal inside. Subsequently, the lead frame 1 is conveyed to the adhesive sheet attaching step C. Hereinafter, the adhesive sheet attaching step C to the cutting / bending step D will be described in detail with reference to the drawings. In this figure, it is assumed that the lead frame 1 is in a state in which the surface of the outer lead 8 is already solder-plated. Reference numeral 10 is an adhesive sheet coated with an adhesive 10a which is hardened by irradiation of ultraviolet rays and whose viscosity is reduced.
A plurality of outer leads projecting from one side surface of the die 9 are connected and attached as one unit. At this time, in this embodiment, the entire portion where the adhesive sheet 10 is likely to come into contact with the outside to be scratched, that is, the outer surface when the outer lead 8 is bent as shown in FIG. The adhesive sheet may be attached to both the front surface and the back surface of the lead. In addition, the minimum plated portion necessary for connecting to an external device, for example, the outer layer. Even if the adhesive sheet is attached only to the tip portion of the lead, the effects described later can be obtained). In this way, by sticking the adhesive sheet, the plated portion on the surface of the outer lead can be protected from the outside, and the outer lead is connected to strengthen and strengthen the lead. It is also possible to prevent. Next, the lead frame 1 is conveyed to the cutting / bending process D,
The lead frame lateral frames 11 and 11 forming the lead frame 1 are connected to the tab lead 2 and the tie bar 7 and the lead frame vertical frames 12 and 12 are formed to the outer lead. 8,8
A plurality of ICs 13 can be obtained by cutting and separating. If the outer sheet 8 is shipped or transported with the adhesive sheet attached, the outer lead 8 can be surely prevented from bending. Next, the separated IC 13 is subjected to a test process E if necessary, and then the IC 13 is transported to a UV irradiation process F. Here, the adhesive sheet 1
0 by irradiating UV (ultraviolet ray), the adhesive 10
Cure a. As a result, the adhesive 10a loses its viscosity, and the IC is removed in the next adhesive sheet removing step G.
It is possible to easily peel off the adhesive sheet 10 from 13.

By the way, as shown in FIG. 7, for example, outer leads 16 and 17 in which different ICs 14 and 15 are in contact with each other.
The adhesive sheet 18 may be attached in common to the above.

Next, the operation and effect obtained in this embodiment will be described.

(1) The plated lead surface is attached with an adhesive seal.
It is possible to prevent external impacts from being directly applied to the plating on the lead surface by protecting the lead surface. Therefore, the effect of preventing peeling of the plating surface and generation of scratches can be obtained.

(2) As described above, it is possible to prevent the plating from peeling off, so that it is possible to obtain an effect that soldering to an external device can be reliably performed.

(3) By connecting the surfaces of a plurality of leads with an adhesive sheet, the leads are reinforced by the adhesive sheet, so that an effect of preventing the lead bending can be obtained. .

(4) The material cost of the adhesive sheet is reduced by forming the adhesive sheet only on the portion which is plated and is necessary for connecting to an external device, that is, only the tip of the outer lead. The effect that it can be reduced compared to the case where it is attached to the entire outer lead is obtained.

(5) By attaching an adhesive sheet in common to the opposing outer leads of the adjacent ICs, the above-mentioned tape is attached.
It is possible to obtain the effect of reducing the man-hours for sticking the tape.

(6) By sticking the adhesive sheet between the tie bar and the outer frame, it is possible to obtain an effect that the outer lead can be processed without being affected even in the cutting step of separating the outer lead from the tie bar and the outer frame. To be

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the above embodiments, and various kinds of modifications can be made without departing from the scope of the invention. Needless to say. For example, in this embodiment, the adhesive tape loses its viscous force by being irradiated with ultraviolet rays, but a material whose viscous force is lost by heating or the like may be used. Further, the outer lead plated with a thermoplastic may be sandwiched between the front and back sides to be conveyed during the manufacturing process, and heat may be applied when removing the outer lead. In addition, in the present embodiment, the case where the protection of the plating formed at the time of manufacturing the lead frame is applied is mainly described, but the protection of the plating formed after the completion of the IC is also applied to the plating. Similar effects can be obtained by applying an adhesive tape later.

[0024]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

That is, since the surface of the plated lead can be protected, there is an effect of preventing the occurrence of defects such as scratches, peeling, and stains due to defective plating.

Further, since the outer lead and the lead can be connected and reinforced, the lead bending can be prevented.

[0027]

[Brief description of drawings]

FIG. 1 is a schematic process flow of a method for manufacturing a semiconductor device according to an embodiment of the present invention,

FIG. 2 is a manufacturing explanatory view of a lead frame manufactured by the manufacturing method of FIG.

FIG. 3 is a plan view of a lead frame in which application of an adhesive sheet is completed,

FIG. 4 is a plan view of a lead frame when cutting is performed with an adhesive sheet attached.

FIG. 5 is a perspective view of the IC in which the outer lead is completely bent,

FIG. 6 is a sectional view of an outer lead having an adhesive sheet attached.

FIG. 7 is a plan view of a lead frame for explaining an application example of an embodiment of the present invention.

[Explanation of Codes] 1 ... Lead frame, 2 ... Tab lead, 3 ... Tab, 4 ...
Chip, 5 ... Bonding wire, 6 ... Inner reel
De, 7 ... tie bar, 8, 16, 17 ... outer lead,
9 ... Package, 10, 18 ... Adhesive sheet, 11 ... Release
Horizontal horizontal frame, 12 ... Vertical vertical frame, 13, 1
4, 15 ... IC

Claims (3)

[Claims] 1. An adhesive sheet protects the plated surfaces of a plurality of outer leads formed for inputting and outputting an external electrical signal to and from a plurality of electrodes on a semiconductor chip. A method for manufacturing a semiconductor device, comprising: 2. A step of molding a lead frame having a plurality of chips mounted thereon, and a plurality of platings formed for inputting / outputting an external electrical signal to / from a plurality of electrodes on a semiconductor chip. A sheet attaching step of attaching an adhesive sheet for integrally connecting the outer leads provided with the sheet, and an outer sheet from the frame frame of the lead frame with the sheet attached. Lee
Manufacture of a semiconductor device having a cutting step for separating the cord, a test step for conducting an electrical test through the outer lead, and a sheet removing step for removing the adhesive sheet from the outer lead Method. 3. The adhesive sheet is made of an adhesive whose adhesive strength is reduced by irradiating ultraviolet rays, and by irradiating ultraviolet rays before removing the sheet, the adhesive sheet is adhered to the adhesive sheet. -Easy removal of
A method for manufacturing a semiconductor device as described above.