JPH0582708A - Lead frame and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase the number of pins for a lead frame main body, reduce inner lead spans and enhance heat emission performance. CONSTITUTION:A lead terminal of a second lead frame which is thinner than a first lead frame is joined to an inland 1 on the first lead frame by way of an insulating material 3 while electric continuity is established across the lead terminal of the second lead frame and the inner lead of the first lead frame 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a lead frame used for mounting a semiconductor integrated circuit such as an IC and an LSI, which is composed of an island formed in the center and inner leads formed around the island, and its manufacture. More particularly, the present invention relates to a lead frame and a method for manufacturing the same, which are capable of increasing the number of pins of the lead frame body and narrowing the pitch of the inner lead portions and significantly improving the heat dissipation performance.

[0002]

2. Description of the Related Art Generally, lead frames are often used for mounting semiconductor integrated circuits such as ICs and LSIs.
The lead frame is usually composed of an island formed in the center and inner leads formed around the island.

That is, the conventional lead frame has a low thermal expansion coefficient alloy such as Fe-Ni alloy (Ni: about 42-50.5 wt%, 42 alloy is typical) or Fe-Ni-Co. Alloy (Kovar alloy, Ni:
29 wt% -Co: about 17 wt%), Cu-based alloys, etc.
There are many alloy types. The structure thereof has a cross-sectional shape as shown in FIG. 6, and is composed of only the metal plate of the island 1 and the inner leads 2 formed around the island 1.

By the way, this type of lead frame is suitable for a metal plate in order to obtain a certain degree of rigidity in order to prevent deformation in the manufacturing process, transportation, and subsequent processes such as a semiconductor integrated circuit mounting process. Thickness is required.

Further, the patterning of the shape of the lead frame is performed by a press working method, that is, a method of obtaining a metal plate by punching with a press using a die having a desired pattern, or a working method by etching, that is, a method of forming a metal plate on a metal plate. Manufactured by the method of obtaining a shape patterning by coating a photoresist, exposing using a mask having a desired pattern, then developing and patterning the photoresist film, and then corroding the metal plate with an etching solution. To be done.

On the other hand, in recent years, in the field of semiconductor integrated circuits having a multi-function such as semiconductor integrated circuits, especially semiconductor integrated circuits for specific purposes, the number of terminals tends to increase with higher integration. On the other hand, the semiconductor integrated circuit chip tends to be larger than the conventional one, but is restricted in terms of its absolute size, so that high definition is progressing. There is. Also, multi-functionalization,
Along with the demand for higher integration, higher definition, and higher speed processing, the problem of increased heat generation from the semiconductor integrated circuit has led to urgent demand for heat dissipation measures.

In this way, the multifunctionalization of the semiconductor integrated circuit,
As the number of terminals and the pitch of pitches have been narrowed due to higher integration, higher definition, and higher processing speed, the corresponding lead frame has more pins of the main body and narrower pitch of the inner lead parts. And the demand for improvement of heat dissipation is increasing.

However, with respect to the above-mentioned press working method, due to problems such as mold design and manufacturing, press technology, etc., it has already reached its limit.

Also, regarding the processing method by etching, the thickness of 0.15 is used in the present technology because of the problem of side etching caused by using wet etching.
In the case of 0 mm 42 alloy, the inner lead has a minimum of 0.2
It is said that the lead frame body has a large number of pins and the inner lead portion has a narrow pitch, which is said to be 00 mm (the lead width is 0.100 mm minimum), which meets the technical requirements due to the recent market trends already mentioned. , It is already the limit.

Further, regarding the problem of improving the heat dissipation performance, there is a problem that the heat dissipation capacity is too low with the current structure of the lead frame and the size of the island.

[0011]

As described above, in the conventional lead frame, there is a demand for the multi-functionality, high integration, high definition, and high speed processing of the semiconductor integrated circuit, which accompanies the market trend. There is a problem in that the heat dissipation performance is low, in addition to the fact that the lead frame body cannot have a large number of pins and the inner lead portions cannot have a narrow pitch.

The present invention has been made to solve the above problems, and its purpose is to increase the number of pins in the lead frame body and to narrow the pitch of the inner lead portions, and at the same time, to dissipate heat. An object of the present invention is to provide an extremely reliable lead frame capable of remarkably improving performance and a manufacturing method thereof.

[0013]

In order to achieve the above-mentioned object, first of all, in the invention described in claim 1, an island formed in the central portion and inner leads formed around the island are formed. In a lead frame used for mounting a semiconductor integrated circuit such as an IC, an LSI, etc., a second lead frame thinner than the first lead frame is formed on an island of the first lead frame through an insulator. The lead terminals are joined to electrically connect the lead terminals of the second lead frame and the inner leads of the first lead frame.

According to the third aspect of the invention, a lead is used for mounting a semiconductor integrated circuit such as an IC or LSI, which is composed of an island formed in the center and inner leads formed around the island. In a method of manufacturing a frame, a step of joining an insulator on the island of the first lead frame, and joining a lead terminal of a second lead frame on the island of the first lead frame via the insulator A step of cutting the lead terminal of the second lead frame at the island end, and a step of electrically connecting the lead terminal of the second lead frame and the inner lead of the first lead frame. Made of.

Here, in particular, the lead terminals of the second lead frame and the inner leads of the first lead frame are
It is made to conduct by wire bonding.

[0016]

Therefore, in the lead frame and the manufacturing method thereof according to the present invention, the second lead frame thinner than the first lead frame material is formed on the island of the first lead frame through the insulator. By joining the lead terminals, it is possible to easily cope with an increase in the number of pins of the lead frame body, a narrower pitch of the inner lead portions, and an improvement in heat dissipation performance.

Further, since the thickness of the second lead frame is sufficiently smaller than the thickness of the first lead frame, the influence of side etching during etching is small, and the dimensional accuracy of patterning can be easily controlled. You can
From this, it becomes possible to increase the number of pins and to narrow the pitch of the inner lead portions.

Further, since the lead terminal obtained from the second lead frame is held by the island via the insulator, there is little fear of deformation in the process such as the mounting process of the semiconductor integrated circuit.

Further, as compared with the size of the island of the conventional lead frame, the size of the island can be expanded by the size of the lead terminals held by the island of the lead frame of the present invention, thereby improving the heat dissipation performance. You can

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a partial sectional view showing a structural example of a lead frame according to the present invention.

That is, the lead frame of this embodiment is
As shown in FIG. 1, a lead terminal 4 of a second lead frame, which is thinner than the thickness of the first lead frame, is bonded onto the island 1 of the first lead frame through an insulator 3, The lead terminal 4 of the second lead frame and the inner lead 2 of the first lead frame are electrically connected by the wire bonding 5.

Next, a specific method for manufacturing the lead frame of this embodiment will be described with reference to FIGS.

First, a 0.150 mm-thick 42 alloy was used, and a negative resist PMER (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. was dip-coated on both surfaces of the 42 alloy, and a mask having a desired pattern was used. , Exposure and development are performed, and then the outer lead pitch of 0.
With 300 mm (lead width 0.150 mm) and inner lead pitch 0.200 mm (lead width 0.100 mm),
The first lead frame 6 having 360 pins is manufactured (FIG. 2). Here, a ferric chloride solution (solution temperature 40 ° C., concentration 665 g / l) was used as the etching solution.

Next, 42 having a width of 35 mm and a thickness of 0.070 mm is used.
Using alloy tape, punch out both sides with a die, provide sprocket holes 7 for alignment, and perform alignment in the sprocket holes 7, and make both sides of 42 alloy tape, for example, by Tokyo Ohka Kogyo Co., Ltd. Negative resist PMER (trade name) is applied by dipping, exposure and development are performed using a mask having a desired pattern, and then an outer lead pitch of 0.20 is obtained by an etching method.
0 mm (lead width 0.100 mm) and inner lead pitch 0.150 mm (lead width 0.080 mm), 36
A second lead frame 8 having 0 pins is produced (FIG. 3).
Here, the etching liquid is ferric chloride liquid (liquid temperature 4
0 ° C., concentration 665 g / l) was used.

Next, using an adhesive body in which the epoxy adhesive 10 having a thickness of 18 μm is provided on both surfaces of the polyimide film 9 having a thickness of 20 μm, alignment is performed in the guide hole and the sprocket hole, and the first adhesive is used. The lead frame 6 and the second lead frame 8 are bonded on the island 6A of the first lead frame 6, and the lead terminals 8A of the second lead frame 8 protruding from the island 6A are connected to the mold 11. And cut (Figs. 4 and 5).

Thereafter, after the surface treatment of the lead terminals 8A of the second lead frame 8 is performed, the lead terminals 8A of the second lead frame 8 and the first lead frame 6 are formed.
The inner leads 6B are electrically connected by wire bonding (not shown).

As described above, it is possible to manufacture a lead frame which can easily meet the demands for increased pin count of the lead frame body, narrowed pitch of the inner lead portions, and heat dissipation performance.

As described above, in this embodiment, on the island 1 of the first lead frame, with the insulator 3 interposed,
The lead terminals 4 of the second lead frame, which are thinner than the thickness of the first lead frame, are joined to electrically connect the lead terminals 4 of the second lead frame and the inner leads 2 of the first lead frame. It was made to let.

Therefore, the following various effects can be obtained.

(A) Since the lead terminal 4 of the second lead frame, which is thinner than the thickness of the first lead frame, is bonded onto the island 1 of the first lead frame via the insulator 3, It is possible to increase the number of pins in the lead frame body and to reduce the pitch of the inner lead portions.

(B) The thickness of the second lead frame material is
Since it is sufficiently thinner than the thickness of the first lead frame material,
There is little effect of side etching when etching,
Therefore, it becomes possible to easily control the dimensional accuracy of patterning, and it is possible to increase the number of pins in the lead frame body and narrow the pitch of the inner lead portions.

(C) Since the lead terminal 4 obtained from the second lead frame is held by the island 1 of the first lead frame via the insulator 3, it can be used in a process such as a semiconductor integrated circuit mounting process. There is little concern about deformation.

(D) Since the size of the island 1 can be expanded by the size of the lead terminal 4 held by the island 1 of this embodiment, the size of the island can be increased compared with the size of the island of the conventional lead frame. It becomes possible.

From the above, the multifunctionalization of the semiconductor integrated circuit,
It is possible to sufficiently meet the demands associated with market trends such as high integration, high definition, and high speed processing.

In the above embodiment, the second lead frame material is made of 42 alloy having a thickness of 0.070 mm. However, in the manufacturing process of the lead frame, in the case of 42 alloy, 0.050 mm is used. It is said to be the limit. Further, as the material of the lead frame, another metal or alloy may be used.

[0037]

As described above, according to the present invention, when a lead frame is manufactured, an insulator is bonded onto the island of the first lead frame and the insulator is bonded onto the island of the first lead frame. The lead terminal of the second lead frame is joined via the via, the lead terminal of the second lead frame is cut at the island end, and the lead terminal of the second lead frame and the inner lead of the first lead frame are connected. By electrically connecting the
On the island of the lead frame, through the insulator,
The lead terminal of the second lead frame, which is thinner than the thickness of the first lead frame, is joined to electrically connect the lead terminal of the second lead frame and the inner lead of the first lead frame. Therefore, it is possible to provide an extremely reliable lead frame capable of increasing the number of pins of the lead frame main body, narrowing the pitch of the inner lead portions, and significantly improving the heat dissipation performance, and a manufacturing method thereof.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a lead frame according to the present invention.

FIG. 2 is a partial cross-sectional view showing a first lead frame in the example.

FIG. 3 is a partial cross-sectional view showing a second lead frame in the example.

FIG. 4 shows a first lead frame and a second lead frame in the same embodiment.
FIG. 4 is a partial cross-sectional view showing a state at the time of joining with the lead frame.

FIG. 5 is a partial cross-sectional view showing a state after the second lead frame in the same embodiment is cut from the frame.

FIG. 6 is a partial cross-sectional view showing a configuration example of a conventional lead frame.

[Explanation of symbols]

1 ... Island, 2 ... Inner lead, 3 ... Insulator, 4
... lead terminal, 5 ... wire bonding, 6 ... first leadframe, 6A ... island, 6B ... inner lead, 7 ... sprocket hole, 8 ... second leadframe, 9 ... polyimide film, 10 ... epoxy adhesive , 11 ... Mold.

Claims (4)

[Claims] 1. A lead frame used for mounting a semiconductor integrated circuit such as an IC or an LSI, which comprises an island formed in the center and inner leads formed around the island, The lead terminal of the second lead frame, which is thinner than the thickness of the first lead frame, is joined onto the island via an insulator, and the lead terminal of the second lead frame and the first lead frame are joined. A lead frame characterized in that it is electrically connected to the inner lead of. 2. The lead frame according to claim 1, wherein the lead terminal of the second lead frame and the inner lead of the first lead frame are electrically connected by wire bonding. 3. A method of manufacturing a lead frame, which comprises an island formed in the center and inner leads formed around the island and is used for mounting a semiconductor integrated circuit such as an IC or an LSI. Bonding an insulator on the island of the lead frame, bonding a lead terminal of the second lead frame on the island of the first lead frame via the insulator, Cutting the lead terminal of the lead frame at the island end, and electrically connecting the lead terminal of the second lead frame and the inner lead of the first lead frame. Characteristic lead frame manufacturing method. 4. The lead frame manufacturing method according to claim 3, wherein the lead terminals of the second lead frame and the inner leads of the first lead frame are electrically connected by wire bonding. Method.