JPH01241833A - Wire bonding - Google Patents

Abstract

PURPOSE:To shorten a time for bonding one wire by dividing the constant speed zone of a descending tool into at least two stages, and making the speed of the constant speed zone of the first stage continued to a high speed zone greater than that of the constant speed zone of the second stage. CONSTITUTION:When a capillary 7 arrives at a position L2, it is rotated at a first constant speed V3 only during a period from t2 to t4. When it then arrives at a position L3, it is rotated at a second constant speed V2 set under a bonding process condition to t5. Here, since the speed V3 is faster than the speed V2, the period of time in which it arrives from the L2 to a L0 is shortened by a period from t3 to t5 as compared with the case of a conventional method designated by a one-dotted chain line. Here, the descending speed is divided into the two stages. However, in order to perform similar function, it may be controlled in multiple stages.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a wire bonding method for connecting an electrode of an IC chip and a lead electrode with a wire.

[Conventional technology]

Fig. 2 shows an example of the configuration of a conventional wire bonding device, in which a circular arc is formed in the direction of arrow Z in the figure, centered on a double fulcrum (2) supported by an XY tape/L' (1). Approximate vertical movement block supported for vertical movement (
3), a bonding arm mount (4), a bearing guide (3b) of the block (3), a bearing (5a) guided by the bearing guide (3b), a link plate (5b), and a link plate (5b). It consists of a motor (6) that moves to Further, the bonding arm mount (4) has a bonding arm (8) attached with a tapered cylindrical capillary (7) having a through hole in the center.
is installed and supported. Furthermore, the bonding arm mount (4) has a contact (4B) and is pressed by a spring (9) attached to the vertical movement block (3). Contacts (3a) (4a) are connected to electric wires (10a) (lo
b) is connected and in electrical continuity.

Next, the operation of the device constructed from the above will be explained.

The movement of the capillary (7) in the XY force direction is performed using the XY tape) L
This is done by z(1). Further, the movement of the capillary (7) in the vertical direction (Z direction) is performed by forward and reverse rotation of the motor (6). That is, as the motor (6) rotates, the vertical movement block (3) moves up and down together with the bonding arm mounting base (4) and the bonding arm (8) via the link plate (5). In this way, the capillary (7) is moved in the XY force direction and in the vertical direction to connect the wire (12) to the bonding surface (11). During bonding, due to the double fulcrum (2), the vertical movement block (3) and the bonding arm mount (4) will move when the cab free (7) hits the bonding surface (11).
) stops descending, and only the vertical movement block (3) descends.
As the contacts (3a) and (4a) separate, the spring (9)
A load is applied to the pounding arm mounting base (4) from D. In this way, the capillary (7) is connected to the bonding surface (
11), the contact loses electrical continuity), and reaching the bonding surface (11) can be detected as an electrical signal. As is well known, the downward movement of wire bonding is switched between a high speed range and a constant speed range.

This will be explained with reference to FIG. First, the capillary (7) is L
At this point, rotate the motor (6) at high speed and lower the cab free (7) to the L2 position.

Next, from position L2, the motor (6) rotates at a constant speed of low speed v2, collides with the bonding surface (11) at position LO, and bonding is started. At this time, the constant velocity value of V2 and the moving distance L2-LO are closely related to the impact load, which is a factor that determines the reliability of bonding, and these values are determined by the bonding process conditions. With this setting value, the l wire bonding time t3-t
l is determined.

[Problem to be solved by the invention J] In the conventional wire bonding method, only one constant speed range is set, and the time required for bonding one wire is automatically determined from the bonding process conditions. However, no further improvement in productivity can be expected, and conversely, if productivity is emphasized and the descending speed in the constant speed range is increased, there will be large variations in impact load, and variations in bonding quality will occur. There were issues with product reliability and production management.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a wire bonding method that can shorten the time required for bonding l-wires.

[Means for Solving the Problems J] The wire bonding method according to the present invention divides the constant speed range of tool descent into at least two stages, and divides the speed of the first stage constant speed range following the high speed range into two stages. The speed is set to be higher than the speed in the constant speed range of the second stage.

[Function j] The wire bonding method according to the present invention sets the first uniform velocity p faster than the second uniform velocity among the two stages to shorten the descending time, and sets the second uniform velocity to be faster than the bonding process conditions. By setting this, it is possible to shorten the descent time while obtaining exactly the same process conditions as before.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, when the capillary (7) reaches the position L2, it is rotated from t2 to t4 at a first constant velocity v3,
Then, upon reaching position L3, it is rotated at tsi at a second constant speed v2 set by the bonding process conditions. Here, the first constant velocity v3 is the second constant velocity V2
y) is also faster, the time from L2 to LO is shorter by t3-4,5 than in the conventional method shown by the dashed line in FIG.

Although the descending speed is set in two stages here, multi-stage control may be used to achieve the same function.

[Effect of the Invention] As described above, the present invention divides the constant velocity region into at least two stages, and divides the speed of the first stage constant velocity region that is continuous with the high velocity region into the second stage constant velocity region. Since the speed is set higher than that of 1, the time required for bonding the l-wire can be shortened and productivity can be improved.

[Brief explanation of the drawing]

1 is a diagram showing the operation of an embodiment of the present invention together with graphs, FIG. 2 is a block diagram of a conventional device, and FIG. 3 is a diagram showing the operation of FIG. 2 together with graphs. In the figure, (7) is a capillary, and (8) is a bonding arm. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a wire bonding method in which the bonding arm is lowered through a high speed region, then through a low constant speed region and the capillary is brought into contact with the bonding surface, the above constant speed region is divided into at least two stages, and the above high speed region 1. A wire bonding method characterized in that the speed in a constant velocity region of the first stage is greater than the speed of the constant velocity region of the second stage.