摘要
针对引线键合机中键合点位置误差形成的成因与特点,提出了键合位置误差圆拟合修正法。首先,让焊头以不同角度旋转,标记出不同旋转角度时,键合点在图像坐标系下的坐标值。然后,利用改进的最小二乘圆拟合法,根据标记坐标拟合出键合轨迹方程。根据方程即可计算出焊头以任意角度旋转运动时,键合点位置的图像坐标值。最后,将图像坐标系转换为运动坐标系,控制键合工具实现精确定位运动。实际应用表明,经过圆拟合修正后,键合点的位置误差由0.68 mm减小到0.07 mm左右,大幅提高了键合点的位置精度,可准确实现焊接区域键合。
A method of circle fitting for correcting bonding position error was proposed in consideration of reason and characteristic of the error in ultrasonic wire bonder.First,rotating the bonding head of the wire bonder and making marks in a lead frame to get image coordinate values.Then,a circular locus model was set up with improved least square circle fitting method.Based on the model,the corrected bonding position in image coordinates can be got when the bonding head rotated at any angle.Finally,the image coordinates was converted to motion coordinates to control the head rotate and translate,and so make the bonding tool located accurately.The practical application shows that the bonding position error is reduced from 0.68 mm to 0.07 mm by this method.The bonding tool location precision is improved greatly and can accurately bond in the welding area.
出处
《半导体技术》
CAS
CSCD
北大核心
2011年第7期549-553,共5页
Semiconductor Technology
基金
吉林省科技发展计划项目(20090355)
关键词
超声波键合机
键合工具
位置误差
椭圆拟合
精度
ultrasonic wire bonder
bonding tool
position error
ellipse fitting
precision
