레이저 열-압착 본딩 시스템의 Lateral Force 감소를 위한 유연 힌지의 설계 (Design of flexure hinge to reduce lateral force of laser assisted thermo-compression bonding system)

서지정보

· 발행기관 : 한국금형공학회
· 수록지 정보 : Design & Manufacturing / 14권 / 3호 / 23 ~ 30페이지
· 저자명 : 이동원, 하석재, 박정연, 윤길상

초록

Laser Assisted Thermo-Compression Bonding (LATCB) has been proposed to improve the “chip tilt due to thedifference in solder bump height” that occurs during the conventional semiconductor chip bonding process. The bondingmodule of the LATCB system has used a piezoelectric actuator to control the inclination of the compression jig on amicro scale, and the piezoelectric actuator has been directly coupled to the compression jig to minimize the assemblytolerance of the compression jig. However, this structure generates a lateral force in the piezoelectric actuator when thecompression jig is tilted, and the stacked piezoelectric element vulnerable to the lateral force has a risk of failure.
In this paper, the optimal design of the flexure hinge was performed to minimize the lateral force generated in thepiezoelectric actuator when the compression jig is tilted by using the displacement difference of the piezoelectric actuatorin the bonding module for LATCB. The design variables of the flexure hinge were defined as the hinge height, theminimum diameter, and the notch radius. And the effect of the change of each variable on the stress generated in theflexible hinge and the lateral force acting on the piezoelectric actuator was analyzed. Also, optimization was carried outusing commercial structural analysis software. As a result, when the displacement difference between the piezoelectricactuators is the maximum (90um), the maximum stress generated in the flexible hinge is 11.5% of the elastic limit ofthe hinge material, and the lateral force acting on the piezoelectric actuator is less than 1N.

영어초록

Laser Assisted Thermo-Compression Bonding (LATCB) has been proposed to improve the “chip tilt due to thedifference in solder bump height” that occurs during the conventional semiconductor chip bonding process. The bondingmodule of the LATCB system has used a piezoelectric actuator to control the inclination of the compression jig on amicro scale, and the piezoelectric actuator has been directly coupled to the compression jig to minimize the assemblytolerance of the compression jig. However, this structure generates a lateral force in the piezoelectric actuator when thecompression jig is tilted, and the stacked piezoelectric element vulnerable to the lateral force has a risk of failure.
In this paper, the optimal design of the flexure hinge was performed to minimize the lateral force generated in thepiezoelectric actuator when the compression jig is tilted by using the displacement difference of the piezoelectric actuatorin the bonding module for LATCB. The design variables of the flexure hinge were defined as the hinge height, theminimum diameter, and the notch radius. And the effect of the change of each variable on the stress generated in theflexible hinge and the lateral force acting on the piezoelectric actuator was analyzed. Also, optimization was carried outusing commercial structural analysis software. As a result, when the displacement difference between the piezoelectricactuators is the maximum (90um), the maximum stress generated in the flexible hinge is 11.5% of the elastic limit ofthe hinge material, and the lateral force acting on the piezoelectric actuator is less than 1N.

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