JPH02250366A - Leadframe for outer lead with soldering material - Google Patents

Abstract

PURPOSE:To enable high precision bonding to a high density and compact ceramic package by fixing tips of a plurality of leads to one another with a soldering material like a narrow tape. CONSTITUTION:Tips of a plurality of leads 10 are fixed to one another with a solder material 16 like a narrow tape. Since the tips of the leads 10 are fixed to one another in one line with the solder material 16 like a narrow tape, the tips of the leads do not move in disorder. Therefore junction handling can be performed smoothly so that deformation of the leads can be prevented. Thus even if a leadframe material is made to be thin and narrow in a side brazed type ceramic semiconductor device being compact and highly dense, bonding can be performed without deformation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lead frame for outer leads used in a side-raised ceramic semiconductor device.

[Prior Art] A ceramic semiconductor device of the type shown in FIG. 3 is used as a highly reliable IC ceramic semiconductor device. In this ceramic semiconductor device, a metal outer lead 10 that conducts electrical signals between the semiconductor chip and the outside is bonded to the side surface of a ceramic package 12 using a solder material such as an Ag alloy.

The method of joining the outer lead 10 is shown in FIGS. 4 and 5.
As shown in the figure, connect the outer lead 10 to the lead frame 1.
A ceramic package 12 is prepared by cladding the tip of each lead with solder material 16.
The method used was to align the parts, overlap them, fuse them, and join them.

[Problems to be Solved by the Invention] However, there has been a problem in that it is difficult to overlap the lead frame for outer leads with respect to the ceramic package, and connection defects are likely to occur.

In particular, in recent years, this problem has attracted attention as lead frame materials have become thinner due to the miniaturization and higher density of electronic devices.

Specifically, for example, a frame material having a thickness of 0.07 mm is also used. In addition, the lead width and lead pitch have become narrower, and frame materials with a lead width of 0.2 mm are now being used. With such thinner and narrower leads, the tip of the lead may be deformed during bonding and handling, resulting in a large rr.
It is the tu point.

This deformation of the lead tips is due to the fact that the lead tips are separated from each other and tend to move unevenly, and it has been found that if the lead tips can be connected to each other, deformation of the lead tips can be prevented.

Therefore, lead frame materials used in plastic packages are taped to prevent lead deformation by adhering polyimide tape to the leads.

However, such taping is not allowed in ceramic packages where the lead frame material is exposed outside the package without being covered like in plastic packages.

The present invention solves the above-mentioned problems and prevents deformation of the leads during bonding between the leads and the ceramic package by fixing the lead tips with a long and thin tape-shaped solder material, thereby creating a high-density, small-sized ceramic package. The purpose is to enable high-precision joining to.

[Means for Solving the Problems] In the outer lead lead frame of the present invention used in a side-brazed ceramic semiconductor device, each lead tip of a plurality of leads is fixed to each other by an elongated tape-shaped solder material, Irregular movements are no longer visible.

[Function] The lead ends of the lead frame configured as described above are plated with Au or the like. Then, a long and narrow tape-shaped solder material is attached thereto, but since this attachment can be done by leaving the lead frame stationary, the tip ends of the leads will not be disturbed or deformed when the solder material is attached.

In this way, the lead frame of the present invention that utilizes solder material as a fixing means has a structure in which the lead tips are lined up and fixed to each other using 411I long tape-shaped solder material, so that the lead tips may not be aligned. Therefore, joint handling is performed smoothly, and lead deformation can be prevented.

Furthermore, the lead frame of the present invention allows accurate positioning of the lead tips when bonded to a ceramic package. Therefore, during joint soldering, metallization can be applied only to the lead joints of the ceramic package, and when the joints are heated above their melting point, the molten solder material is welded only to the lead joints.

After the outer leads are joined in this manner, each lead can maintain a separated state, and the purpose of conducting the electrical signals can be completely achieved.

[Example] A Fe-N1-Co alloy (Kovar) for a lead frame with a thickness of 0.1 mm was etched to form a side blazed type with a diameter of 20 mm and a length of 100 mm as shown in Fig. 2. A lead frame 14 was obtained. The lead tip width of the outer lead 10 of this lead frame 14 is 0.3
It was mm.

This lead frame 14 was plated with Ag to a thickness of 3 μm.

Next, A g/28 Cu was used for outer lead joining.
Alloy (melting point 780°C) brazing material or solder material 16
The tape was processed into a long and thin tape with a thickness of 0.2 mm, and then cut into a length of 94 mm to match the tip of the lead.

As shown in FIGS. 1 and 2, after overlapping the solder material 16 on the tips of the leads 10 of the lead frame 14, the solder material 16 is heated at 250 to 300°C and 30 to 50 g/mr in an inert gas.
d, thermocompression bonding was carried out for 15 to 20 seconds to obtain an integrated lead frame 14 with solder material 16 attached, as shown in FIG. In addition, in this thermocompression bonding, the solder material 16
There was no noticeable deformation.

On the other hand, for brazing, a ceramic package (not shown) which has been metallized only on the part is prepared, and A according to the present invention is used.
Place the lead frame 14 with g-alloy solder material on the side of the ceramic package! They are combined and heated to 850° C. in a reducing atmosphere to melt the Ag alloy solder material 16 and join the outer leads 10 and the ceramic package to produce a highly reliable side-brazed ceramic semiconductor device with leads on the side surfaces. Obtained. There was no deformation of the outer lead 10 during this bonding and handling, and the quality of the semiconductor device was improved.

In the present invention, similar processing was obtained not only for Ag alloy solder materials, but also for Au alloy solder materials, PB gold alloys, and various alloy solder materials.

[Effects of the Invention] Since the present invention is configured as described above, it produces effects as described below.

(1) Even when the lead frame material becomes thinner and narrower in side-brazed ceramic semiconductor devices that are becoming smaller and more dense, the effect of preventing lead deformation is extremely large.

(2) The solder material and lead frame are integrated,
It is possible to improve yield and reduce man-hours in the assembly process.

[Brief explanation of drawings]

FIG. 1 is a plan view of a lead frame for outer leads according to the present invention. 2 is a side view of the outer lead lead frame of FIG. 1. FIG. FIG. 3 is a perspective view of a type of ceramic semiconductor device that can use the lead frame for outer leads according to the present invention. FIG. 4 is a plan view of a conventional lead frame for outer leads. 5 is a side view of the outer lead lead frame of FIG. 3. FIG. (Left space on this page) In the figure, reference numbers represent the following: 10... Lead, 12... Ceramic package, 14... Lead frame, 16... Solder material,

Claims (1)

[Claims] Used in side blazed ceramic semiconductor devices,
1. A lead frame for outer leads having a plurality of leads, characterized in that the tips of each lead are fixed to each other with elongated tape-shaped solder material.