Material Removal Model for Lapping Process Based on Spiral Groove Density

Taekyung Lee,Hanchul Cho,Sangjik Lee,Doyeon Kim,Haedo Jeong,Hyoungjae Kim

doi:10.3390/app11093950

Taekyung Lee, Hanchul Cho + Show 4 more

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https://doi.org/10.3390/app11093950

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Abstract

The increasing demand for single-crystal wafers combined with the increase in diameter of semiconductor wafers has warranted further improvements in thickness variation and material removal rate during lapping to ensure price competitiveness of wafers; consequently, the lapping process has gained the attention of researchers. However, there is insufficient research on the effect of platen grooves on the lapping process. In this study, the parameters to describe grooves were defined in order to understand their influence on the lapping process, and a material removal model was suggested based on indentation theory and subsequently experimentally validated. The results indicate that changes in groove density affect the lubrication condition at the contact interface as well as the probability of abrasive participation by varying the oil film thickness. When fabricating the groove for a lapping platen, a groove density at the critical groove density (CGD) or higher should be selected. The higher the groove density, the easier it is to avoid the CGD, and the higher is the material removal rate. The results of this study will enable engineers to design lapping platen grooves that are suitable for the production of modern semiconductor wafers.

Highlights

Semiconductors are manufactured by depositing an epitaxial layer on single-crystal wafers through the metal–organic chemical vapor deposition (MOCVD) process and fabricating electrically functional components on the epitaxial layer [1]
The frictional force (f ) was applied to the lapping head with the wafer attached in the direction of rotation of the platen, which subsequently transfers to the head guide
The in terms terms of of the a similar tendency as in the inverse inverse number number of ofthe thegroove groovedensity, density,which whichshowed showed a similar tendency the oil film thickness and frictional force on the. This indicates that, under as the oil film thickness and frictional force on the Stribeck curve. This indicates that, unthe the experimental conditions in this the wafer and platen are separated by the oil der experimental conditions instudy, this study, the wafer and platen are separated by film the when the groove density is lower than

Summary

Introduction

Semiconductors are manufactured by depositing an epitaxial layer on single-crystal wafers through the metal–organic chemical vapor deposition (MOCVD) process and fabricating electrically functional components on the epitaxial layer [1]. To manufacture wafers for semiconductors, the raw material is melted at a high temperature and grown into single-crystal ingots. The grown ingots are cut into thin wafers through the multiwire sawing process and polished flat through the double-sided and single-sided lapping processes. The lapping process is the last process that determines the thickness and thickness variation of a wafer. If the thickness variation of the wafer is large, it will be out of the depth of field (DOF) in the lithography process. As wafers increase in diameter, further improvements in thickness variation and material removal rate are

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