JPH08116010A - Manufacturing method of electric terminal and device used for the method - Google Patents

Abstract

PURPOSE: To avoid the unfavorable phenomena such as tilt and tortion of lead by a method wherein after stamping out the electric terminal, it is pressed to remove the residual stress in the stamping step and then the connecter between the electric terminals is removed. CONSTITUTION: A metallic band material 10 wound around a reel 9 is led in a stamping press 5 while wounding out of the reel 9 on the other hand, a male force 6 is lowered to be closed in a female force 7 while intermittently feeding the metallic band material 10 to respective molding stages 8a-8n for stamping respective molding stages 8a-8n to take the required shape of a lead frame 1 by the final molding stage. Next, the metallic band material 10' as the electric terminal stamped out by the stamping press 5 is led into a thermal press 11 to remove the residual stress in the stamping off time by thermal press 11. Later, the lead 3 inner end and the connecter 4' of an IC mounting board 2 are cut off by a connector cutter 21. Through these procedures, the unfavorable phenomena such as tilt and tortion of the lead 3 can be avoided.

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 an electric terminal such as an IC lead frame for mounting an IC chip and an apparatus used for the method.

[0002]

2. Description of the Related Art As shown in FIG. 1, an IC lead frame 1 has an IC chip mounting plate 2 in the center thereof.
It has a large number of leads 3 extending in parallel from two sides or four sides. In the press machine for punching out this IC lead frame 1, the lead pitch of the lead frame is very small, so a plurality of forming stages are formed in the male mold and the female mold, and the metal strip material is sequentially fed to each forming stage (intermittent feeding). While punching out, the final form is obtained at the final stage.

At this time, the leads of each IC lead frame are connected to each other by the retainer 4 left by the punching so as to maintain the lead pitch, and as shown in FIG. 2, the inner ends of the leads 3 and the mounting plate 2 are held. After cutting off the connecting portion 4'of the IC chip, the IC chip is mounted on the IC chip mounting plate 2 (at this time, each corner of the mounting plate 2 is connected to the retainer 4 and is integrated with the band material), the IC chip Bonding wiring between the lead 3 and the lead 3, packaging of the IC chip with an insulating material, and the like are performed, and then the connecting portion such as the retainer 4 is cut off to form a so-called IC package.

[0004]

As described above, since the leads of the IC lead frame form the external terminals of the IC chip and have a very small pitch and are fine, very precise processing accuracy is required. After cutting the connecting portions 4 and 4 ′ at the inner and outer ends of the lead, especially the connecting portion 4 ′ at the inner and outer ends of the lead from the IC lead frame, a bad phenomenon of tilting or twisting occurs in the lead, and this phenomenon is caused by miniaturization of the lead. It is difficult to ignore the occurrence of defective products and the deterioration of the yield rate.

As a result of investigating the cause, the inventors have found that the residual stress when the metal strip material is punched is
It appears as an external phenomenon such as the above deformation as the lead becomes thin and fine, and becomes fragile, and this external phenomenon was suppressed and overlooked when the leads were connected and reinforced by connecting parts, but It was found that when the connecting portion was cut off in the process, it appeared as an external phenomenon such as the above deformation.

[0006]

The present invention has been made on the basis of this finding. As a means therefor, an electric terminal such as an IC lead frame is punched out, and then the electric terminal is hot-pressed. The residual stress at that time is removed, and then the connecting portion for connecting the electric terminals is cut off.

Further, as the apparatus, a hot press machine for hot pressing the electric terminals is installed adjacent to the electric terminal outlet side of the electric terminal punching press machine to perform line formation.

[0008]

According to the present invention, the residual stress at the time of punching the electric terminals which require the precise punching is removed by the hot press, and the problem of lead deformation after cutting the connecting portion due to the residual stress is solved. Resolve effectively. Also, the means is extremely simple.

Further, burrs and deformations generated during punching can be removed by the hot press. In this case, the pressure applied by the hot press and the heat effectively act to adjust the shape.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 3, reference numeral 5 is a pressing machine, which has a male die 6 and a female die 7 as described above.
The male mold 6 and the female mold 7 have a plurality of molding stages 8a, 8b,
8n is formed, and while the metal strip 10 wound on the reel 9 is unwound from the reel 9, it is introduced into the punching press machine 5 or a strip metal strip having a fixed length is introduced into the punching press machine 5. Then, while sequentially feeding (intermittent feeding) to each of the molding stages 8a, 8b, ... 8n, when the intermittent feeding is stopped, the male die 6 is lowered and clamped with the female die 7, punching is performed in each molding stage, and the final molding stage is performed. At 8n, the required final form of leadframe 1 is obtained.

Further, 11 is a heat press machine, and this heat press machine 11 is a punching metal strip material 10 'of the punching press machine 5.
It is installed next to the sequential feed outlet side.

The electrical terminals punched by the punching press machine 5, that is, the punched metal strip material 10 ', is introduced into the hot press machine 11 and is subjected to hot pressing to cause residual stress (internal strain ... working strain) during punching. ) Is removed. At the same time, it can be used as means for eliminating burrs and punching deformation that occur during punching of the hot press 11. The pressure and heat applied by the hot press effectively act to adjust the burr and punching deformation.

A cleaning machine 12 is arranged between the punching press machine 5 and the heat press machine 11, or a cleaning machine 12 is arranged on the outlet side of the heat press machine 11 to prevent the surface of the IC lead frame 1 from being contaminated. Remove.

The heat press machine 11 is provided with an upper pressure plate 13 and a lower pressure plate 14, and the surfaces of the pressure plates 13 and 14 opposed to each other,
That is, the pressure surfaces 15 and 16 are parallel to each other and flat,
The two surfaces are closely attached to the front and back surfaces of the IC lead frame 1 to apply a uniform surface pressure to remove the above residual stress, and burrs are applied with a pressure so that they are converged within the plane.

The pressure plate 14 is formed of a hard ceramic as a suitable example. For example, aluminum oxide, zirconia, etc. are applied.

As a heating means for the pressure board 14, for example, a coil heater 17 is built in the pressure board 14 or a heater is arranged on the side opposite to the pressure surface of the pressure board 14.

Further, as shown in FIG. 4, the above heat press 1
The upper and lower pressure plates 13 and 14 can be placed in a specific inert gas atmosphere. Reference numeral 18 denotes a heating tank filled with an inert gas such as nitrogen, and the pressurizing plates 13 and 14 are clamped and opened in the heating tank 18 so that the heating tank 18 is heated.
The punched metal strip 10 'introduced from one side is hot pressed in an inert gas atmosphere in the tank.

This hot-pressed stamped metal strip 10 "
Is led out from the other side of the heating tank 18, and then passed through a connecting portion cutting machine 21 arranged on this outlet side to cut off the inner end of the lead 3 and the connecting portion 4'of the IC mounting plate 2. As the connecting portion cutting machine 21, a press machine that adds required processing to the IC mounting plate 2 and the leads 3 can be used. If the strip material 10 ″ ″ after cutting the connecting portion is long, it is wound up on the winding reel 19.

The metal strip 10 ″ ″ after the connection portion is cut off is subjected to an IC package manufacturing line, which is a post-process, for mounting the IC chip on the IC chip mounting plate 2, bonding wiring, and packaging, After that, the retainer 4, which is a connecting portion between the outer ends of the leads protruding laterally of the package body, is cut off.

Alternatively, the take-up reel 19 may not be provided, and the post-process for manufacturing the IC package may be arranged as a continuous line on the exit side of the connection cutting machine 21.

Preferably, the pressure plate 1 of the heat press machine 11 is used.
The temperatures given by 3 and 14 are set to be higher than the recrystallization temperature peculiar to the material of the metal strip material 10, that is, the lead frame 1 (electrical terminal) or near the precipitation hardening temperature.

An iron / nickel alloy or a copper / tin / phosphorus alloy is used as a material for the lead frame 1. When the iron / nickel alloy is used, the temperature applied by the pressure plates 13 and 14 is 400 ° C. or higher, for example, about 715. ° C.

In the case of an electric terminal used for a connector such as an IC socket other than the lead frame, phosphor bronze or beryllium copper is used as its material, and the temperature given by the pressure plates 13 and 14 is 315 ° C.
Set near.

The pressurizing plates 13 and 14 maintain the pressed and heated state of the punched metal strip 10 'for a certain period of time. The temperature of the press is determined according to this pressure holding time. The punching time and the hot pressing time are set such that the latter time is lengthened and an absorbing device 20 for absorbing the slack of the punched metal strip 10 'due to a time difference is provided between the punching press machine 5 and the hot pressing machine 11 so that the hot press is performed. Every time the rotation is completed, the feed speed on the outlet side of the heat press machine 11 is increased to synchronize with the punching press machine 5.

Although the above has described the IC lead frame 1, it also includes the case where the present invention is applied to a fine pitch electric terminal of a connector such as an IC socket.

In the present invention, a large number of unit electric terminals such as a plurality of unit lead frames 1 are punched out in succession on a long metal strip, or a fixed small number of unit electric terminals are formed on a regular strip. Can be punched out, or a single electrical terminal can be punched out.

[0027]

According to the present invention, the residual stress generated by the punching press of the electric terminals such as the IC lead frame, which is required to be densely punched, is removed by the hot press and is caused by the residual stress. It is possible to effectively solve the problem of lead deformation after cutting the connecting portion,
Also, the means is extremely simple.

Also, burrs and deformations that occur during punching can be rectified satisfactorily by the action of heat and pressure applied by the hot press, and because this heat press can be rectified, a low-cost mold can also be used, which is economical. Is.

[Brief description of drawings]

FIG. 1 is a plan view illustrating a state after punching processing of an IC lead frame manufactured according to the present invention.

FIG. 2 is a plan view showing a state in which a connecting portion between an inner end of the IC lead frame and an IC mounting plate is cut off.

FIG. 3 is a side view schematically showing an apparatus for manufacturing an electric terminal represented by the lead frame.

FIG. 4 is a cross-sectional view showing a main part of a hot press machine in the manufacturing apparatus.

[Explanation of symbols]

 1 lead frame 2 IC chip mounting plate 3 lead 4 connecting part of outer end of lead (retainer) 4'connecting part of inner end of lead 5 punching press machine 11 heat press machine 13 press board 14 press board

Claims (2)

[Claims] 1. A punching method for an electric terminal, comprising the steps of punching the electric terminal, then subjecting the electric terminal to hot pressing to remove residual stress during punching, and then cutting off a connecting portion between the electric terminals. Manufacturing method. 2. An electric terminal manufacturing apparatus, wherein a hot press machine for hot pressing the electric terminals is provided adjacently to the electric terminal outlet side of the electric terminal punching press machine.