Study on Improvement of Material Removal Rate in Chemo-Mechanical Grinding (CMG) of Si Wafer

Abstract

Silicon wafer thinning process is meeting great challenges to fulfill requirements of ultra-thin IGBT for automotive applications. Chemo-mechanical grinding (CMG) process is potentially emerging stress relief thinning process which combines the advantages of fixed abrasive machining and chemical mechanical polishing (CMP). A major issue in CMG of Si wafers is the relatively low material removal rate (MRR). This paper studies the influence of the wheel specifications and grinding conditions on the MRR of CMG. Two sets of three-factor two-level full factorial designs of experiment (DOE)[1] are employed to reveal the main effects and interacted effects of CMG wheel specifications and grinding parameters on MRR. The optimal combination scenarios for improving MRR of CMG are analysized and obtained. By use of the optimal CMG wheel and grinding parameters, the MRR of more than 60nm/min is achieved.

Design and evaluation of soft abrasive grinding wheels for silicon wafers

“…Ceria (CeO 2 ) was mainly chosen as an abrasive of the SAGW and has exhibited good performance in the silicon ultraprecision grinding. [20][21][22][23][24][25][26] Chemical reaction between CeO 2 abrasives and silicon during the grinding process was also studied. 26,27 However, few researchers investigated the grinding performance of SAGWs with different soft abrasives.…”

“…The problems include unstable grinding performance, low material removal rate (MRR), grinding burn, wafer surface scratches and so on. 24,25 This study builds upon the previous research on SAGW design. It optimizes design and formulation of the SAGW.…”

“…Ultrasmooth and damage-free silicon wafers could be achieved with the CMG process. [20][21][22][23][24][25][26][27] Although CMG is found to be promising for wafer grinding, it still has problems that need to be solved. The problems include unstable grinding performance, low material removal rate (MRR), grinding burn, wafer surface scratches and so on.…”

Development of CMG Wheels for Stress Relief in Si Wafer Thinning Process

“…By effective use of chemically reactive abrasives, CMG offers better dimensional accuracy and similar surface integrity when comparing to CMP [5]. As a potential stress relief process subsequent to rapid grinding, CMG has been intensively studied to investigate the effects of wheel geometry and grinding condition on the removal rate [6], and effects of bond materials and additives on the surface quality [7] in our previous researches. The obtained results indicated that properly controlled pressure and heat were key to chemical reaction between abrasive and Si.…”