Etching Performance Improvement On Semiconductor Silicon Wafers With Redesigned Etching Drum

Abstract

Proses etching atau punaran melibatkan pelbagai tindak balas kimia dan sangat penting dalam menentukan kualiti wafer silikon. Projek ini menyelesaikan masalah utama wafer ketika proses punaran, iaitu keserakan data pembuangan sisa wafer di sepanjang dram punaran. Cecair punaran yang digunakan dalam projek ini terdiri daripada komposisi asid HNO3, HF, and CH3COOH. Dram punaran telah diubahsuai untuk menyelesaikan masalah pembuangan sisa wafer yang rendah di setiap wafer pertama dan terakhir dalam sesuatu kompatmen dram. Tujuan utamanya adalah untuk mengurangkan jurang perbezaan variasi dalam pembuangan sisa wafer, di mana nilai pembuangan silicon adalah rendah berbanding pembuangan silicon wafer di tengah kompatmen. Antara cadangan tersebut adalah menambahkan "kepingan wafer PVC tahan asid" di sebelah wafer pertama dan terakhir dalam setiap kompatmen. Selepas memperoleh keputusan yang memberangsangkan, kepingan PVC tersebut dikekalkan dalam rekabentuk dram yang baru. Sifat wafer pertama dan terakhir dinilaikan untuk memastikan tiada kualiti yang terjejas berbanding wafer-wafer di tengah kompatmen. Morfologi permukaan dan kekasaran wafer (purata kekasaran;Ra dan kekasaran "skewness";Rms) menggunakan mikroskop tujahan atom (AFM) dianalisis untuk dibandingkan dengan dram lama. Keseragaman pembuangan wafer tanpa masalah pembuangan rendah di hujung kompatmen telah diperhatikan. Kata kunci: Proses punaran, permukaan "Micromachining", wafer silicon, pembuangan silicon wafer, kekasaran permukaan wafer silikon Etching process involves various chemical reactions and reflects significantly on the silicon wafer quality. The paper addresses the major problem on wafers during etching that is wafer removal distribution throughout etching drum compartment. The etchant used in this study were the composition of HNO3, HF, and CH3COOH. The etching drum has been redesigned to overcome the lower removal problem at the end of each compartment and to reduce the big disparity in wafer removal distribution. The proposed idea is to install a piece of "circumferential acid resistant PVC wafer" for the remaining empty slot (empty area without wafers) at each end of a compartment. The permanent PVC piece with certain gap at each end is then fabricated for the new drum design. The characteristics of the end wafers are compared with other wafers in the compartment to study the etching difference that leads to this problem. Surface morphology and surface roughness parameters (arithmetic roughness mean; Ra and surface skewness [roughness root mean square]; Rms) using atomic force microscopy (AFM) comparison between old drum design (big wafer gap) and new drum design (smaller gap with additional PVC chip) had been analyzed. The uniformity without lower removal problem at the end compartment is observed in removal distribution graph. Key words: Etching process; surface micromachining; silicon wafer; etching removal; silicon wafer surface roughness