JPH07111309A - Lead frame and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an insulating tie bar on the lead of a lead frame in such a manner that no hindrance is given to a resin molding process which is one of the manufacturing processes of a semiconductor device. CONSTITUTION:In a lead frame on which insulating tie-bars 3a and 3b are provided in the direction crossing a plurality of leads 2, a recessed part 2c, corresponding to the shape of the insulating tie bar 3a or 3b, is provided and at least a part of the insulating tie bar is inserted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame used for manufacturing a semiconductor device and a method for manufacturing the same. More specifically, when a semiconductor device is manufactured by connecting a semiconductor chip to a lead frame and resin-molding it, it is possible to inspect the connection state of the leads and the quality of the semiconductor chip itself before resin-molding the lead frame and its manufacture. Regarding the method.

[0002]

2. Description of the Related Art As shown in FIG. 4A, a conventional lead frame 44 comprises a frame 41, a plurality of leads 42 directly connected to the frame 41, and a tie bar 43 integrally formed with the frame 41 and the leads 42. There is. This tie bar 4
3 functions as a lead fixing bar that connects and fixes a plurality of leads 42 to each other, and also as a dam bar that prevents unnecessary spread of the molding resin when the semiconductor chip is mounted on the lead frame 44 and is resin-molded. It is functioning.

In addition to the lead frame 44 of FIG. 4A, a lead frame having an island for mounting a semiconductor chip is also widely used. In this case, the islands are usually directly connected to the frame by suspension leads.

A lead frame 44 in which the inner leads of the leads 42 are fixed with a polyimide-based adhesive tape 45 as shown in FIG. 4B in order to secure the positional accuracy when the leads 42 have a fine pitch is known. Has been.

By the way, in order to enhance the function of the semiconductor device, and to enhance the response speed and packaging density, one or more semiconductor chips are mounted and sealed on the semiconductor mounting substrate. Is to be done. In this case, as the semiconductor mounting substrate, there is used a substrate including a printed wiring board having external conduction terminals on its peripheral portion and external conduction leads connected to the external conduction terminals. Such a semiconductor device is manufactured as shown in FIG. The process will be described below.

First, a conventional lead frame 44 is prepared (FIG. 5A).

Next, a printed wiring board 46 for mounting one or more semiconductor chips is prepared, and the external conduction terminals 47 and the leads 42 of the lead frame 44 are appropriately made of an adhesive material such as an adhesive tape. Then, the semiconductor mounting substrate 48 is electrically fixed by a wire bonding method, a bump connection method, or the like to obtain a semiconductor mounting substrate 48 (FIG. 5B).

Next, a semiconductor chip is mounted on the printed wiring board 46, and the entire printed wiring board 46 is sealed by a sealing means 49 such as a mold resin or a ceramic package (FIG. 5C).

Next, the frame 41 is cut off from the leads 42, the tie bars 43 connecting the adjacent leads are cut off, and the leads 42 are trimmed if necessary, and then the lead 42 is formed as shown in FIG. A semiconductor device as shown is obtained.

However, the conventional lead frame 44
Since the lead 42 and the tie bar 43 are an integrated structure made of a conductive material, when a semiconductor device is manufactured using such a lead frame, the connection state of the individual leads and the electrical conductivity of the semiconductor chip itself. To conduct a physical examination,
As shown in FIG. 5 (d), it was necessary to perform an encapsulation operation to fix the individual leads, cut off the frame from the leads, and also remove the tie bar to electrically isolate the individual leads. . Therefore, even if it is found in the inspection that the semiconductor chip itself is defective or the lead connection state is incomplete, it is necessary to replace the semiconductor chip or reconnect the leads because the sealing operation has already been performed. However, there is a problem in that the yield rate is lowered and the manufacturing cost cannot be reduced.

In order to solve this problem, it is conceivable to use an insulating tie bar made of an insulating resin as the tie bar in order to make each lead electrically independent. Further, such an insulating tie bar may be formed on the lead as a dam bar or a lead fixing bar.

[0012]

However, as shown in FIG. 6, a dam bar 50 made of an insulating resin is formed on the lead 42.
Since the protruding resin protrudes from the surface of the lead 42 when the fixing bar 51 is formed, the protruding resin lowers the positional accuracy of the mold and the lead used in the resin molding step which is one of the manufacturing steps of the semiconductor device. However, there is a problem that the life of the mold is shortened, the injection of the mold resin into the mold is hindered, or the lead is deformed.

The present invention is intended to solve the above problems of the prior art, and in the case of providing an insulating tie bar on the lead of the lead frame, a resin molding step which is one of the manufacturing steps of the semiconductor device. The purpose is not to interfere with.

[0014]

DISCLOSURE OF THE INVENTION The inventors of the present invention have provided a recess in the lead so that the insulation tie bar provided on the lead of the lead frame does not protrude from the lead surface, and at least a part of the insulation tie bar is provided in the recess. It was found that the above-mentioned object can be achieved by inserting the above, and the present invention has been completed.

That is, according to the present invention, in a lead frame in which an insulating tie bar is provided on a lead in a direction crossing a plurality of leads, a recess corresponding to the shape of the insulating tie bar is provided in the lead, and the recess is insulated. Provided is a lead frame in which at least a part of a sex tie bar is fitted.

Further, the present invention is the above-described method for manufacturing a lead frame, wherein a frame is formed on both the step of forming etching resist on both sides of the lead frame plate material and the etching resist layer formed on both sides of the lead frame plate material. And a step of forming a positive pattern of leads, a step of etching the lead frame plate material from both sides, and a step of peeling and removing the etching resist. As for the etching resist layer on the lead surface to be formed, a pattern is formed by removing the etching resist of the portion corresponding to the recess of the lead, and then the lead frame plate material is etched into the lead frame shape by the process of etching from both sides. And recessed in the lead part Obtain the formed sheet material, after peeling the etching resist, to provide a method of manufacturing a lead frame, characterized in that by supplying the insulating resin in the recess of the lead to form an insulating tie bar.

[0017]

In the lead frame of the present invention, at least a part of the insulating tie bar is fitted in the recess provided in the lead. Therefore, the degree of protrusion of the insulating tie bar from the lead surface can be reduced, and the surface of the insulating tie bar formed on the lead can be made substantially flush with the surface of the lead. Therefore, it is possible to prevent the resin molding step, which is one of the manufacturing steps of the semiconductor device, from being hindered.

When a semiconductor device is manufactured using the lead frame of the present invention, the leads can be electrically isolated by cutting the frame from the leads. Therefore, for example, a lead frame of the present invention is placed on a printed wiring board on which a semiconductor chip is mounted, terminals of the printed wiring board and leads of the lead frame of the present invention are connected to form a semiconductor mounting board, After that, if the frame is cut off from the leads and the leads are electrically isolated, it becomes possible to inspect the connection state between each lead and the terminal of the printed wiring board before sealing the semiconductor mounting board. . Also, by mounting a semiconductor chip on a semiconductor mounting board with a good lead connection,
Inspection of the semiconductor chip itself is also possible before sealing. Therefore, when the connection state of the leads or the semiconductor chip itself is defective, it is possible to reconnect the leads or replace the semiconductor chip before sealing.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacturing method of the present invention will be described below in detail with reference to the drawings. In addition, in each figure, the same reference numeral indicates the same or equivalent component.

A plan view of a preferred embodiment of the lead frame of the present invention is shown in FIG. As shown in the figure, the lead frame 4 includes a frame 1, a plurality of leads 2 directly connected to the frame 1, an insulating tie bar 3a connecting the outer lead portions 2a of the lead 2 and an inner lead portion 2b of the lead 2 And an insulating tie bar 3b that connects the two to each other. In this case, the insulating tie bar 3a of the outer lead portion 2a functions as a dam bar,
The insulating tie bar 3b of the inner lead portion 2b functions as a lead fixing bar. In this embodiment, the insulating tie bars 3a and 3b are partial sectional views of the lead 2.
As shown in (b), it is fitted in a recess 2c provided in the lead 2. With such a structure, the protrusion of the insulating tie bar 3a or 3b from the surface of the lead 2 can be substantially eliminated.

The insulating tie bar 3b can be omitted when the lead pitch is relatively large.

Such an insulating tie bar 3a or 3b
Can be formed by disposing an insulating resin such as a thermoplastic resin or an ultraviolet curable resin in the recess 2c of the lead 2 by a dispenser method or a screen printing method.

Next, the method of manufacturing the lead frame of the present invention will be described with reference to FIG. 2 which is an enlarged view of the vicinity of the insulating dam bar, taking as an example the manufacturing of a lead frame having an insulating dam bar as the insulating tie bar.

First, as shown in FIG. 2A, an etching resist layer 22 is formed on both sides of the lead frame plate material 21.
a and 22b are formed.

Next, a positive pattern of the frame and the leads is formed on the etching resist layers 22a and 22b formed on both surfaces of the lead frame plate material 21 by photolithography. At the time of forming this positive pattern, the etching resist layer 22a on the surface side where the recess of the lead is to be formed is also removed on the lead portion corresponding to the recess (FIG. 2B).

Next, the lead frame plate material 21 is etched from both sides using an etching solution such as ferric chloride solution, so that the lead frame plate material 21 has a lead 2 having a recess 2c. It has a shape (FIG. 2C).

Next, the etching resist layer is peeled and removed by a conventional method (FIG. 2 (d)).

Finally, an insulating resin is supplied to the recess 2c of the lead 2 to form the insulating tie bar 3a. As a result, a lead frame having the leads 2 shown in FIG. 2 (e) is obtained.

Next, an example of manufacturing a semiconductor device using the lead frame of the present invention will be described with reference to FIG.

First, a multilayer printed wiring board 31 as shown in FIG. 3 (a) is prepared, and this wiring board 31 is subjected to press working or counterbore processing to obtain a printed wiring board 32 as shown in FIG. 3 (b). Semiconductor mounting printed wiring board 30 in which an insulating frame 33 is integrated via a support bar 34
Process to 0.

Separately from the printed wiring board 300, a lead frame 4 of the present invention comprising leads 2, a frame 1 and an insulating tie bar 3a is prepared (FIG. 3 (c)). At this time, it is preferable to make the inner dimension t2 of the lead frame 4 larger than the outer dimension t1 of the insulating frame 33 of the semiconductor-mounting printed wiring board 300. This makes it possible to easily cut off the lead 2 of the frame 1 described later.

Next, the semiconductor mounting printed wiring board 300 shown in FIG. 3B and the lead frame 4 shown in FIG.
As shown in FIG. 3 (d), the leads 2 of the lead frame 4 are laser-welded to the external conduction terminals 35 of the printed wiring board 32 by using an adhesive member (not shown) such as an adhesive or a double-sided adhesive tape. Method or soldering method.

Next, by cutting the frame 1 of the lead frame 4 from the leads 2 by a laser processing method or a V-cut method, the respective leads 2 are made electrically independent and insulated from the printed wiring board 32. The support bar 34, which is integrated with the frame 33, is removed by a conventional method. As a result, the semiconductor mounting substrate shown in FIG. 3 (e) is obtained. In the semiconductor mounting board having such a configuration, the individual leads 2 are electrically independent, so that the connection state between the individual leads 2 and the external conduction terminals 35 can be inspected before sealing. it can.

A semiconductor chip is mounted on the printed wiring board 32 of the semiconductor mounting substrate in which the leads 2 are connected well by a conventional method. Also in this case, since the leads 2 are electrically independent of each other, it is possible to perform an operation confirmation inspection of the semiconductor chip itself and the semiconductor chip and the printed wiring board before sealing.

Next, a semiconductor chip is mounted on the printed wiring board 32 on the semiconductor mounting substrate by a wire bonding method or a bump method. Then, an operation inspection of the semiconductor chip is performed, and if the inspection result is good, the semiconductor chip is sealed by a sealing means 36 such as a molding resin or a ceramic package formed by a transfer molding method or the like, and finally the insulating property is obtained. The frame 33 is removed. As a result, a semiconductor device as shown in FIG. 3F can be manufactured.

[0036]

By manufacturing a semiconductor device using the lead frame of the present invention, the connection state of individual leads, the semiconductor chip itself, and the semiconductor chip and the printed wiring board can be inspected before sealing. . Therefore, if the connection state of the leads or the semiconductor chip itself is defective, reconnection of the leads or replacement of the semiconductor chip can be performed before sealing.

Further, according to the present invention, the protrusion of the insulating tie bar from the lead surface can be substantially eliminated. Therefore, it is possible to prevent the resin molding step, which is one of the manufacturing steps of the semiconductor device, from being hindered.

[Brief description of drawings]

1 is a plan view of a lead frame of the present invention (see FIG.
It is (a)) and a partial cross section figure (FIG.1 (b)).

FIG. 2 is a manufacturing process diagram of the lead frame of the present invention.

FIG. 3 is a manufacturing process diagram in the case of manufacturing a semiconductor device using the lead frame of the present invention.

FIG. 4 is a plan view of a conventional lead frame.

FIG. 5 is a manufacturing process diagram for manufacturing a semiconductor device using a conventional lead frame.

FIG. 6 is an explanatory diagram of a problem when an insulating tie bar is used for the lead frame.

[Explanation of symbols]

 1 frame 2 lead 2c recess 3a, 3b insulating tie bar 4 lead frame

Claims (3)

[Claims] 1. In a lead frame in which an insulating tie bar is provided on a lead in a direction crossing a plurality of leads, a recess corresponding to the shape of the insulating tie bar is provided in the lead, and the recess has at least the insulating tie bar. A lead frame that is partially fitted. 2. The lead frame according to claim 1, wherein the insulating tie bar is a dam bar made of an insulating resin provided on the outer lead portion or a lead fixing bar made of an insulating resin provided on the inner lead portion. 3. A step of forming an etching resist on both surfaces of a lead frame plate material, a step of forming a positive pattern of a frame and leads on both etching resist layers formed on both surfaces of the lead frame plate material, and a lead frame plate material. The method of manufacturing a lead frame according to claim 1, comprising a step of etching from both sides and a step of peeling and removing the etching resist, wherein the recess is formed in the step of forming a positive pattern of the frame and the lead in the etching resist layer. As for the etching resist layer on the lead surface to be formed, a pattern is formed by removing the etching resist of the portion corresponding to the recess of the lead, and then the lead frame plate material is etched into the lead frame shape by the process of etching from both sides. And the lead part has a recess A method for manufacturing a lead frame, comprising: forming a plate material, removing an etching resist, and then supplying an insulating resin to the recesses of the leads to form an insulating tie bar.