JPS62128130A - Wire bonding method - Google Patents

Abstract

PURPOSE:To improve the bondability and to prevent wires from falling off, by forming a ball at the tip end of a wire inserted through a capillary by means of electric discharge of an electric torch directly before bonding the wire at the first bonding point on a work. CONSTITUTION:A work is fed to and properly positioned at the bonding position, and a ball is formed at the tip end of a wire projected from a capillary by means of electric discharge of an electric torch. Immediately after that, the capillary is lowered for bonding the wire at the first bonding point on the work. During the formation of the ball, the wire is clamped by a clamper so as to prevent the wire from being removed from the capillary. After the formation of the ball, the clamper is left open. Since the ball is formed directly before the wire bonding, the wire can be bonded before the temperature of the ball decreases. Accordingly, the bondability can be improved and the wire can be prevented from falling off.

Description

[Detailed description of the invention] [Industrial applicability! ! ? ] The present invention relates to a wire bonding method using a thermocompression wire bonder, a thermocompression bonding ultrasonic wire bonder, etc.

[Prior Art] As is well known, a wire honda is used to connect a wire to a first bond point and a second bond point of a workpiece having a pellet fixed to a lead frame. Among such wire bonders, thermocompression bonding wire Honda, thermocompression bonding ultrasonic wire bonder, etc., when performing wire bonding to the first bonding point of the work, an electric torch is used to touch the tip of the wire that has been inserted into the capillary and protrudes from the capillary. A ball is formed due to the discharge.

Conventionally, in wire bonding to the first bonding point of a workpiece, a ball is formed at the tip of the wire protruding from the tip of a capillary while the workpiece is being sent to the bonding position, and the workpiece is positioned by discharging an electric torch. After that, the capillary was lowered and wire bonding was performed. Also, the second part of the work: i43rd...
Wire bonding to the first bond point is performed by forming a ball by discharging an electric torch after the wire bonding of the previous second bond point is completed and the wire is cut at the root of the second bond point. be exposed.

[Problems to be Solved by the Invention] Recently, wire bonding to the first bonding point of a workpiece has been caused by wire peeling (
It was found that there were many cases of non-delivery. The cause of this problem would be very simple if it were known, but the reality is that it has puzzled those skilled in the art. As a result of various experiments, the applicant has discovered that
The following findings were made.

It was noticed that although the wire did not peel off to the second, third, etc. first bond points of the workpiece, only the first bond point of the wire often peeled off. When wire bonding to the first bond point of the second, third, etc. of the workpiece, there is no time to feed the workpiece, and wire bonding is performed immediately after forming the ball, so the ball is in a warm state. It seems that good wire bonding is possible.

However, in wire bonding to the first bonding point of the workpiece, a ball is formed while the workpiece is being sent to the bonding position in order to shorten the total wire bonding time. For this reason, during wire bonding, the temperature of the ball decreases and hardens it, resulting in poor bondability and easy peeling of the wire.

An object of the present invention is to provide a wire bonding method that has excellent bondability and prevents wire peeling.

[Means for solving the problem] The problem with the above conventional technology is that after the workpiece is transferred and positioned at the bonding position, immediately before wire bonding is performed on the first bonding point of the workpiece, the capillary is This problem can be solved by discharging the tip of the inserted wire with an electric torch to form a ball and performing wire bonding.

[Example] Hereinafter, an example of the wire bonding method of the present invention will be described. After the workpiece is sent to the bonding position and positioned, a ball is formed at the tip of the wire protruding from the capillary by discharging an electric torch, and then the capillary is immediately lowered to perform wire bonding at the first bonding point on the workpiece. At this point, the wire is clamped with a clamper to prevent it from coming off the capillary when forming the ball. After the ball is formed, the clamper is opened.

In this way, since the ball is formed immediately before wire bonding to the first bonding point of the work, the ball can be wire bonded before the temperature drops. This improved the pondability and reduced wire peeling.

Note that if the wire bonder stops during wire bonding, bonding is restarted so that a ball is formed just before the capillary descends for bonding.

[Effects of the Invention] As is clear from the above description, according to the present invention, after the workpiece is transferred and positioned at the bonding position, immediately before wire bonding is performed at the first bonding point of the workpiece, Wire bonding is performed by discharging the tip of the wire inserted into the capillary with an electric torch to form a ball, which provides excellent bondability and prevents the wire from peeling off.

Claims (1)

[Claims] After the workpiece has been transferred and positioned at the bonding position, immediately before wire bonding is performed at the first bonding point on the workpiece, an electric torch is used to discharge electricity at the tip of the wire inserted into the capillary to form a ball. A wire bonding method characterized by performing bonding.