关键词: 倒装芯片, 封装, 多层互连结构, 聚焦离子束, 电路修改

Abstract:

Flip-Chip packaging is an important packaging form for high-performance devices． Its unique packaging form brings new challenges to circuit-edit ( CE) ． A CE method for ICs of flip-chip /multilayer interconnected structure was proposed in this paper by combining the techniques of thinning the back of the chip，deep and wide trench etching technology based on Focused Ion Beam ( FIB) ，trench etching endpoint monitoring based on dynamic grating diffraction fringes，and FIB circuit modification． Firstly，this method uses a global polishing thinning method to reduce the thickness of the flip-chip to about 70 μm． Then uses deep and wide trench etching technique and dynamic grating diffraction fringe-based trench etching endpoint monitoring technique to perform deep and wide Si trench etching． The chip is further thinned to about 4 μm，and then the circuit is edited with a FIB CE technique． The successful CE results of the M1 metal open circuit in a 6-layer metal CMOS chip show that the proposed method can effectively accomplish the modification of open or short circuit in flip-chip /multilayer interconnected structured ICs．

Key words: flip-chip, packaging, multilayer interconnected structure, focus ion beam ( FIB) , circuit edit