Ultrasonic System Normalization on Wedge Bonders

Operators of ultrasonic wedge bonders desire that bonders using the same process inputs achieve identical process outputs. In practice, it has been found that process outputs can differ between bonders operating with the same inputs. A common practice to bring the performance of bonders into closer agreement is to make small adjustments to the input parameters. These adjustments are looked upon unfavorably because they are typically determined using non-standardized, non-automated procedures, and further, the process inputs for each bonder then need to be tracked separately. Therefore, there is a strong desire to normalize the performance of one bonder to another using an automated procedure. This paper presents a method to normalize the performance of a number of bonders based upon bond deformation measurements taken automatically by the bonder. Several case studies are presented that demonstrate the effectiveness of this normalization procedure in improving the similarity of process outcomes across a group of bonders. The results show that bonders after Ultrasonic Normalization make bonds with more similar end deformation, shear strength and bond width than the bonders before Ultrasonic Normalization.