Patent ID: 7004372

Claim:
A method for determining optimum bond parameters including a bond force F B and an ultrasonic variable P B of a wire bonder for a bond process, whereby for this determination a number of bond cycles are carried out, whereby for each bond cycle a wire connection is made between a connection point of a semiconductor chip and a connection point of a substrate in that a wire end protruding out of a capillary is melted into a ball and then, in a bond position, the wire ball is attached to the connection point of the semiconductor chip, then the wire is pulled through to the required length, formed into a wire loop and attached to the connection point of the substrate, and whereby the bond parameters to be optimized are each varied in discrete steps within a predefined range, wherein with each bond cycle n, after attaching the wire ball to the connection point of the semiconductor chip, the following steps are carried out: a) applying a predetermined bond force F B1 , b) moving the capillary out of the bond position in a predetermined direction whereby the current I n (t) flowing through the drive which moves the capillary is monitored in the course of time t, c) stopping the capillary as soon as the current I n (t) decreases, d) determining a maximum of the current I n,max from the progression of the current I n (t) established during steps b) and c), and wherein from the values I n,max established with the n bonding processes those values for the bond parameters are determined as optimum bond parameters for which I n,max reaches a maximum.