JP2921121B2 - Manufacturing method of IC lead frame material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a lead frame material for manufacturing an IC, and provides a material which provides a lead frame having high flatness after punching.

[0002]

2. Description of the Related Art As a lead frame material used for manufacturing various ICs, a low thermal expansion coefficient alloy represented by 42% Ni-Fe, a 7% Cu-Fe alloy, a Cu alloy, a stainless steel, or the like is used. I have. With an increase in the degree of integration of ICs, IC lead frames are also shifting from a two-sided terminal type to a four-sided terminal (QFP) type. The material of the QFP type lead frame is particularly strongly required to be flat (coplanarity) in all directions in a product obtained by processing such as punching.

In order to obtain a material having a high coplanarity, that is, a sheet having a low anisotropy, considering that most of the anisotropy of the material is caused by rolling,
Conventionally, a method has been adopted in which a strip obtained by cold rolling is cut into a substantially square shape, and the resultant is rolled in a direction perpendicular to the original rolling direction to a desired thickness. Needless to say, in such a production method, cutting of the band and rolling in a direction perpendicular to the band significantly impair productivity and increase costs, and also anisotropy, shape, dimensions, etc. of each rolled material. There was a great variation in quality, and improvement was desired.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to meet the above-mentioned demands by forming a continuous coil without cutting the strip material by cutting a lead frame material having a coplanarity suitable for manufacturing a QFP type IC lead frame. Rolled as is,
It is an object of the present invention to provide a method of manufacturing a desired thickness.

[0005]

According to the method of manufacturing an IC lead frame material of the present invention, an alloy for an IC lead frame is processed into a thin plate by cold rolling, and a strip of the thin plate is subjected to continuous cross rolling to form a product plate. After rolling to or near the thickness, finish rolling and / or strain relief rolling are performed.

Here, the "cross-rolling" is a method of rolling a long metal material in a direction perpendicular to the direction of feeding into the rolling means, and is disclosed, for example, in Japanese Patent Publication No. 62-45007. Technology. "Strain relief rolling" includes straightening in which the draft is substantially zero.

[0007]

[Function] The above-mentioned cross rolling is a technique for manufacturing a long material having a relatively large width compared to its diameter and thickness for a relatively thin metal material. Although this is a rolling technique that has advantages such as obtaining a product, the inventors have conceived that this cross rolling may help reduce anisotropy in rolling IC lead frame materials. The experiment confirmed that the desired effect was obtained.

Each step will be described with reference to the drawings.
As shown in the figure, a coil of lead frame alloy (6)
Is rolled longitudinally by a cold rolling roll (1), and subsequently rolled laterally by a cross-rolling roll (2) composed of a pair of conical rolls. Thereafter, the product is rolled to a predetermined thickness by a finish rolling roll (3), the distortion is removed by a straightening roll (4), and the product is wound as a product coil (7). According to this process, the anisotropy caused by cold rolling is reduced by cross rolling, which rolls in a direction perpendicular to the cold rolling.

In practice, it may be convenient to carry out each of the above steps independently. FIG. 1 shows each step in succession for easy understanding. Of course, it can also be operated continuously as shown in the figure.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Using the apparatus shown in FIG.
An Ni—Fe alloy was rolled to produce an IC lead frame material. The width and thickness of the material at points A to E in the drawing together with the conditions of each rolling are as follows.

[0011]

[Table 1]

A coil of the product was slit into a ribbon having a width of 50 mm, and this was subjected to a strain relief annealing treatment at 600 ° C. for 1 minute.

The annealed ribbons were subjected to tensile and bending tests to determine anisotropy. The result is
As compared with the conventional simple rolling in only one direction, FIG.
(Elongation) and FIG. 3 (repeated bending at 90 °, average value of 5 pieces). In these figures, "RD" indicates a rolling (longitudinal) direction, and "TD" indicates a direction perpendicular thereto.

[0014]

The lead frame material manufactured by the method of the present invention has less anisotropy than that obtained by the conventional manufacturing method, and therefore, the coplanarity of the lead frame obtained by punching the material is high. According to this manufacturing method, a QFP-type IC lead frame can be manufactured with high productivity, at a reduced cost, and without quality variations.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram for explaining a method of manufacturing an IC lead frame material according to the present invention, in which apparatuses for performing respective steps are continuously arranged.

FIG. 2 is a diagram showing test data of a product according to an example of the present invention.

FIG. 3 is a view showing test data of a product according to the embodiment of the present invention, similarly to FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cold roll 2 Cross roll 3 Finish roll 4 Straightening roll 6 Coil of lead frame alloy 7 Coil of lead frame material

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B21B 1/22 B21D 1/02 H01L 23/50

Claims (1)

(57) [Claims] 1. An alloy for an IC lead frame is processed into a thin plate by cold rolling, and a strip of this thin plate is rolled by continuous cross rolling to a thickness of a product or a thickness close to the product, and then subjected to finish rolling and / or finishing. A method for producing an IC lead frame material, comprising performing strain relief rolling.