JPH077050A - Contact-bonding method of lead wires - Google Patents

Abstract

PURPOSE:To equalize the contact bonding of lead wires by receiving a thrust force during contact bonding with a buffering material into which the tips of a large number of terminal pins break without penetration. CONSTITUTION:A package board 4 is loaded on buffering board 21 which is loaded on a bonding stage 10. A semiconductor chip 2, which connects an inner lead wire of lead wires 8, is loaded on the package board 4 while an outer lead wire of the lead wires 8 is contact-bonded with a terminal 9 on the board 4. The tips of a large number of pins 6 break in, which fall vertically from the board 4 with a thrust force of a bonding tool 11 which thrusts the outer lead wire of the lead wires 8, thereby absorbing the variability of the length of the pins 6. Hard rubber or the like is used for a buffering board 21 which does not allow the penetration of the pins 6 against the thrust force of the bonding tool 11. As a result, a longer pin breaks into the buffering board 21 at a greater depth than a shorter pin 6, which makes the top of the board 4 in parallel to the bottom of the tool 11 and hence equalizes the contact bonding between a large number of lead wires 8 and terminals 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for crimping a lead, and more particularly to a method for crimping a lead to a conductor terminal on the upper surface of a package substrate on which a large number of pins hang down.

[0002]

2. Description of the Related Art FIG. 3 is a schematic sectional view of a semiconductor device.
The semiconductor device 1 accommodates the semiconductor chip 2 in the package 3.

The package 3 is formed by adhering a cap 5 to an insulating substrate 4 on which a large number of pins 6 are aligned and hanging down, and the outer of a large number of leads 8 whose inners are connected to the semiconductor chip 2 via bumps 7 are the substrate. 4 is crimped to each of the conductor terminals 9 which are formed on the upper surface of 4 and communicate with predetermined pins 6.

The crimping of the lead 8 and the terminal 9 is carried out by mounting the package substrate 4 on a metal bonding stage, mounting the semiconductor chip 2 to which the inner portion of the lead 8 is connected on the substrate 4, and positioning the lead 8. After doing
The outer side of the lead 8 is pressed against the terminal 9 by the heated bonding tool, and the pressing force of the bonding tool is received by the pin 6 that contacts the bonding stage.

[0005]

FIG. 4 is an explanatory view (1) of uneven pressing force during crimping, and FIG. 5 is an explanatory view (2) of uneven pressing force during crimping. Is.

In the semiconductor device 1 described with reference to FIG. 3, a large number of pins 6 projecting from the lower surface of the package substrate 4
It is unavoidable that there will be variations in the length. Therefore, as shown in FIG.
When the pins 6 are mounted on the substrate 6, if the lengths of the pins 6 vary, the substrate 4 tilts, and the pressing force of the bonding tool 11 becomes nonuniform.

As a result, the crimping force of the lead 8 whose pressing force is insufficient is reduced and the lead 8 whose pressing force is excessively large.
Mechanical strength is reduced. Further, in the semiconductor device 1 described with reference to FIG. 3, the upper surface of the package substrate 4, particularly the upper surface of the substrate 4 made of ceramic has some undulations, and as shown in FIG. The surface that presses the lead 8 against the terminal 9) is the tool 11
Since it is heated to about 500 ℃, it deforms into a concave shape.

Therefore, for example, when the upper surface of the substrate 4 and the lower surface of the tool 11 are both concave as shown in FIG.
As for the pressing force between the terminal 9 and the terminal 9, the pressing force becomes excessive at the ends of the leads 8 and the terminals 9 in the alignment direction, and the pressing force tends to be too small at the central portion in the alignment direction, resulting in insufficient crimping force and reduced mechanical strength. Connection reliability is reduced.

Therefore, in the crimping of the leads 8 using the stage 10 whose upper surface is thermally deformed and the tool 11 whose distal end surface is thermally deformed, the leads 2 located at the center of the row are pressed against the leads 8 at the aligned end. The pressure is reduced, and the crimping force of the lead 8 having insufficient pressing force is reduced.

As a measure against the variation in the length of the pin 6, there is a method of using a carrier made of ceramic or the like. However, the pressure-bonding carrier that comes into contact with the lower surface of the substrate 4 is affected by the accuracy of the lower surface of the substrate 4, and
It was impractical because it was also affected by thermal deformation of the carrier.

[0011]

The first means of the method according to the present invention is shown in FIG. 1 (a) showing an embodiment thereof, in which the upper surface of the insulating substrate 4 on which a large number of terminal pins 6 hang down is different from each other. A large number of conductor terminals 9 communicating with the terminal pins 6 are formed, and when the conductor leads 8 stacked on the terminals 9 are crimped to the terminals 9 with a crimping tool 11, the buffer members 21 with which the tips of the terminal pins 6 come into contact.
Is mounted on the upper surface of the crimping stage 10, and the pressing force at the time of crimping is received by the cushioning member 21 which is a plate-like cushioning material into which the tips of the terminal pins 6 project and do not penetrate.

The second means of the method according to the present invention is shown in FIG.
Then, the leads 8 are pressure-bonded to the bumps 22. Further, the application example of the first means of the method of the present invention is such that according to FIG. 2 showing the embodiment, the tape-like buffer member 23 is used, and the lead 8 is stopped during the crimping operation of crimping the lead 8 to the conductor terminal 9, The tape-shaped cushioning member 23 so that the tape-shaped cushioning member 23 runs at the end of the crimping operation.
Run intermittently in its length direction.

[0013]

According to the first means, the buffer member 21 absorbs the variation in the length of the terminal pin 6 to eliminate the inclination of the substrate 4. Therefore, the unevenness of the crimping force due to the variation in the length of the terminal pin 6 is eliminated, and the lead 8 and the terminal 9 can be crimped uniformly.

According to the second means, the bumps 22 absorb the deformation of the upper surface of the substrate 4 and the deformation of the lower surface (lead pressing surface) of the pressure bonding tool 11. Therefore, the unevenness of the crimping force due to the deformation of the upper surface of the substrate 4 and the lower surface of the tool 11 is eliminated, and the uniform crimping of the leads 8 and the terminals 9 is enabled.

Further, as an application of the first means, a tape-shaped cushioning member 23 is used, and by running the member 23, the tip portion of the terminal pin 6 used in the first means is pierced and damaged. It is not necessary to replace the buffer member 21 that is provided.

[0016]

1 is an explanatory view of an embodiment of the method of the present invention, and FIG. 2 is an explanatory view of the method of the present invention using a buffer tape.

In FIG. 1A, in which the same reference numerals are used for the same parts as in the above-mentioned drawing, the first embodiment of the method of the present invention is to mount a buffer plate 21 on the bonding stage 10 and place it on the buffer plate 21. The package substrate 4 is mounted, and the semiconductor chip 2 to which the inner of the lead 8 is connected is mounted on the package substrate 4,
The outer of the lead 8 is crimped to the terminal 9 on the substrate 4.

Due to the pressing force of the bonding tool 11 pressing the outer of the lead 8, the tips of a large number of pins 6 that hang down from the substrate 4 project to absorb the variations in the length of the pins 6 and the pressing force of the bonding tool 11. On the other hand, for the buffer plate 21 through which the pin 6 does not penetrate, for example, hard rubber, medium / soft plastic, or the like is used.

Therefore, the long pin 6 penetrates into the buffer plate 21 more deeply than the short pin 6, whereby the upper surface of the substrate 4 is parallel to the lower surface of the tool 11, and the leads 8 and terminals 9 are crimped. Becomes uniform.

In the second embodiment of the method of the present invention, a buffer plate 21 is mounted on the bonding stage 10 and a metal is provided on the terminal 9 in FIG. The package substrate 4 having the bumps 22 formed thereon is mounted on the buffer plate 21, the semiconductor chip 2 is mounted on the substrate 4 so that the outer portions of the leads 8 overlap the bumps 22, and the leads 8 are formed by using the bonding tool 11. The outer of is crimped to the terminal 9.

In this crimping method, the buffer plate 21 absorbs variations in the lengths of many pins 6, and the bumps 22 absorb the deformation of the upper surface of the substrate 4 and the deformation of the lower surface of the tool 11. The crimping of the lead 8 and the terminal 9 becomes more uniform than in the first embodiment of the method of the present invention.

In FIG. 2 in which the same reference numerals are used for the same parts as in the above-mentioned drawing, the third embodiment of the method of the present invention is the buffer plate described above.
Buffer tape made of the same type of buffer material as buffer plate 21 instead of 21
Use 23.

The buffer tape 23 wound around the feeding reel 24 is moved by a predetermined amount (the same amount as the length of the substrate 4) along with the vertical movement of the bonding tool 11.
It travels over 10 and is taken up by take-up reel 25.

As described above, the crimping method using the buffer tape 23 does not require replacement of the buffer plate 21, which is damaged by the tip of a large number of pins 6 protruding by the crimping work, and thus the reliability and productivity of crimping are improved. Contribute to improvement.

[0025]

As described above, according to the method of the present invention, the crimping of the leads is made uniform, which improves the reliability of the electrical and mechanical connection of the leads and reduces the yield due to the crimping failure. There is an effect.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the method of the present invention.

FIG. 2 is an explanatory view of the method of the present invention using a buffer tape.

FIG. 3 is a schematic cross-sectional view of a semiconductor device

FIG. 4 is an explanatory view (1) of uneven pressing force during crimping.

FIG. 5 is an explanatory view (2) of uneven pressing force during crimping.

[Explanation of symbols]

 2 is a conductor lead to be crimped to a conductor terminal 4 is an insulating substrate 6 is a terminal pin hanging from the insulating substrate 9 is a conductor terminal on the upper surface of the insulating substrate 10 is a crimping stage 11 is a crimping tool 21,23 is a buffer member 22 is metal bump

Claims (3)

[Claims] 1. An insulating substrate having a large number of terminal pins (6) depending on it.
A large number of conductor terminals (9) communicating with the terminal pins are formed on the upper surface of (4), and conductor leads (8) are stacked on the terminals.
When crimping the terminal with the crimping tool (11),
A buffer member (21, 23) with which the tips of the terminal pins abut is mounted on the upper surface of the crimping stage (10), and the pressing force at the time of crimping is projected without the tips of the many terminal pins penetrating. A method for crimping a lead, characterized in that it is received by a cushioning member. 2. The buffer member (23) is in the form of a tape, and the lead (8) is stopped during the crimping operation of crimping the conductor terminal (9), and the tape-like member is run at the end of the crimping operation. 2. The lead crimping method according to claim 1, wherein the cushioning member is intermittently run in its length direction. 3. Metal bumps (22) on the conductor terminals (9)
2. The method for crimping the leads according to claim 1, wherein the bumps (21, 23) are used to crimp the leads (8) to the bumps.