JPH0142353Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Field of industrial application This invention is used in the lead bonding process in the assembly process of semiconductor devices, and more specifically, the invention is used for the lead bonding process in the assembly process of semiconductor devices. The present invention relates to an apparatus for collectively bonding the tip end of a lead to a lead bonding location formed on an external substrate by thermocompression bonding.

B. Prior art For example, used in small electronic calculators, etc.
As shown in FIGS. 1 and 2, the MOS/IC is assembled onto a flexible printed circuit board 1 in the following manner. That is, a part of the printed circuit board 1 has MOS/
A rectangular opening 3 that is sufficiently larger than the size of a rectangular semiconductor pellet (hereinafter referred to as pellet) 2 of the IC is formed, and a plurality of conductive patterns extending from the four sides of the opening 3 are formed on the printed circuit board 1 with out leads 4, 4... are deposited and formed. On the other hand, the pellet 2 has a plurality of leads (hereinafter referred to as inner leads) whose ends are bonded to a plurality of electrodes (bonding pads) formed on the periphery of the four sides.
5, 5... extend outward while being adhesively fixed to a rectangular ring-shaped insulating tape 6 made of polyimide or the like.
The inner leads 5, 5, . . . are fixed with tape 6, and their respective inner ends are bonded all at once onto the corresponding bonding pads on the pellet 2 by thermocompression bonding. The outer tip of each inner lead 5, 5... is shaped into a rectangle corresponding to the leaded bonding location 7, 7... of the end in the opening 3 of the outer lead 4, 4..., and the corresponding one is as follows. Connected electrically and mechanically using the TAB method (Tape Automated Bonding method).

Normally, the inner leads 5, 5... are Sn plated,
The leaded bonding points 7, 7, . . . of the outer leads 4, 4, . The heater chips 8 are hollow metal chips such as molybdenum, and are protruding from the lower end surface of the leaded bonding locations 7, 7, . . . arranged on the four sides of the opening 3 of the printed circuit board 1.
The thermocompression bonding portions 8a to 8d are arranged in two rectangular shapes, and each thermocompression bonding portion 8a to 8d attaches a pellet 2 to each leaded bonding location 7, 7... of the printed circuit board 1 on the pedestal 9 as shown in FIG. When a current I is applied to the heater chip 8 in the direction of the arrow in FIG. 5 while the tips of the corresponding inner leads 5, 5... extending from the heater chip 8 are pressed to cause self-heating due to internal resistance, the Au of the lead bonding locations 7, 7... Metsuki and Inner Lead 5,
The Sn plating of 5... is fused to create an Au-Sn eutectic alloy, whereby the inner leads 5, 5... and the outer leads 4, 4... are connected together.

By the way, the printed circuit board 1 is thin and flexible and bends during handling, so the pellet 2
Inner leads 5, 5... and outer leads 4, 4...
An external force such as a bending moment may be applied to the connection part, and if there is a weak bonding strength of the inner leads 5, 5... to the outer leads 4, 4..., the connection may come off or contact failure may occur at that part. Sometimes. Therefore, outer leads 4, 4
Although it is desired that the bonding of the inner leads 5, 5, etc. be sufficiently large and with uniform strength throughout, this has been difficult to achieve. That is, the heater chip 8 that performs the bonding is designed to rapidly generate heat when energized for a short time, but the heat distribution of the thermocompression bonding parts 8a to 8d during this heat generation is such that the end portions of each have better heat dissipation than the central portion. Because of this, the center part is high and the ends are low in the shape of a mountain, and the bonding temperature is set based on the center part. Therefore, the inner leads 5, 5, . . .
When thermocompression bonding is carried out by pressing the tip of the to be bonded portions 7, 7... with uniform pressure, the thermocompression bonding portions 8a to 8a.
A lack of heat occurred at both end portions of 8d, resulting in insufficient bonding strength at the bonding portions at both end portions, resulting in the above-mentioned bonding failure.

C. Purpose of the invention The object of the present invention is to provide a highly reliable TAB type bonding device that solves the problems of the TAB type bonding device described above.

D. Structure of the invention The present invention uses a protruding thermocompression bonding part of a heater chip to bond the tip ends of a plurality of leads extending from a semiconductor pellet to a plurality of corresponding lead bonding locations on a substrate by thermocompression bonding in an annular shape. Then, the lead tip portions are bonded to the lead bonding locations arranged in a circular manner corresponding to the annular thermocompression bonding portion. When the thermocompression bonding portion of the heater chip is formed into an annular shape in this manner, the heat distribution in the thermocompression bonding portion during heat generation becomes uniform due to the circular shape, and therefore good bonding can be performed without fear of insufficient heat.

E Example 6 shows an example in which the present invention is applied to a bonding device for assembling the pellet 2 to the printed circuit board 1.
This will be explained with reference to FIGS. 10 to 10. As a prerequisite for implementing the present invention, as shown in FIGS. 6 and 7, the lead bonding locations 7', 7', etc. of the outer leads 4, 4... on the printed circuit board 1 are arranged on one circle, and The tips of the inner leads 5, 5, . . . extending from the pellet 2 are cut and shaped into a circular shape corresponding to the shape. Further, the opening 3' into which the pellet 2 of the printed circuit board 1 is fitted is also made circular, and the leaded bonding parts 7', 7', etc. are arranged around this opening, and the inner leads 5, 5,... extending from the pellet 2 are formed in an annular shape in advance. A tape 6' adhesively fixed thereon is used.

Accordingly, the present invention provides a device using a heater chip 10 as shown in FIGS. 8 and 9. This heater chip 10 is a hollow metal chip of molybdenum or the like similar to the conventional heater chip, and its feature is that it has one annular thermocompression bonding part 11 of a size opposite to the leaded bonding parts 7', 7', arranged in a circular manner on the lower end surface. It is to protrude in one piece.

Therefore, as shown in FIG. 10, the printed circuit board 1 is placed on the pedestal 9', and the leaded pellet 2 is positioned and supplied to the opening 3' of the board 9', and each inner lead 5, 5 is placed on the board 1.
After placing the circular tips of the inner leads 5, 5... on the same circular lead bonding points 7', 7'..., the heater chip 10 is lowered and the annular thermocompression bonding part 11 is attached to the tips of the inner leads 5, 5.... are pressed against the corresponding leaded bonding points 7', 7'... and the heater chip 10 is energized to generate heat to a predetermined temperature. Since the thermocompression bonding part 11 is annular, the entire part generates heat uniformly, so that all the parts to be bonded are heated uniformly. The bonding conditions for the inner leads 5, 5, . . . at the lead bonding locations 7', 7', .

Note that the present invention is not limited to the above embodiments, but also applies to MOS/IS.
The present invention can be similarly applied to devices in which semiconductor pellets other than those mentioned above are bonded to substrates other than printed circuit boards using the TAB method.

F. Effects of the Invention As described above, according to the present invention, the heat distribution in the thermocompression bonding portion of the heater chip becomes uniform, so that the bonding strength of the TAB method can be easily made uniform, and a highly reliable bonding device can be provided.

[Brief explanation of the drawing]

1 and 2 are a partial plan view and a cross-sectional view taken along the line A-A of the object to be bonded, and FIGS. 3 and 4 are a bottom view of a heater chip in a conventional bonding device and a cross-sectional view taken along the line B-B. Partial cross section,
FIG. 5 is a partial cross-sectional view of the bonding operation using the heater chip shown in FIG. Figure 9 is a bottom view and C showing an embodiment of the heater chip in the present invention.
FIG. 10 is a partial sectional view taken along the line -C, and FIG. 10 is a partial sectional view during bonding operation using the heater chip of FIG. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Semiconductor pellet, 5... Lead (inner lead), 7'... Lead bonding location, 10... Heater chip, 11... Annular thermocompression bonding part.

Claims (1)

[Scope of utility model registration request] In an apparatus having a heater chip that thermally presses each tip of a plurality of electrode external lead leads extending from a semiconductor pellet to a plurality of corresponding lead bonding locations formed on an external substrate, the lead tip and A bonding device characterized in that lead bonding locations are arranged in a circular manner, and the lead thermocompression bonded portion of the heater chip is formed in an annular shape corresponding to the circular arrangement.