現行的智慧手機在高屏幕面積占比率的競爭下,屏幕下指紋識解決方案已成為各手機大廠的賣點之一。如何在有限的手機屏幕下空間,放入更大且更薄的生物(指紋)識別元件將是各生物識別解決方案商設計上一大挑戰。 該論文研究的超聲波生物(指紋)識別元件TFT玻璃基板(500um),須經化學蝕刻的薄化製程將原本厚度減至90um,相較一般傳統TFT面板玻璃基板薄化後厚度300um左右有極大的差異,且單片TFT基板上元件數量也較面板產品多(約500 chips),因此對於薄化後玻璃厚度均勻極為要求,如厚度均勻度不佳時,將會造成後道玻璃切割/裂片作業時,導致切割深度差異,裂片後玻璃邊緣的崩損品質問題,同時對識別功能效益上也會有一定程度的影響。在超薄及厚度均勻度高規格要求條件下,對超聲波生物(指紋)識別元件TFT玻璃薄化製程將是一大考驗。 本論文研究方式是應用田口實驗設計方式(Taguchi Method),改善方式是運用六標準差DMAIC系統流程,以清楚定義問題及問題的範圍,選出關鍵品質特性,並列出關鍵的製程輸出變數、衡量階段收集的資料,再應用田口實驗設計法規畫出最少的實驗組合,衡量重要因子及水準,找出最佳的薄化製程參數設定,再經由製程監控下確認改善方案有效性。 本研究利用「科學化-田口實驗設計」及「系統化-六標準差DMAIC」的問題分析手法,提升研究個案公司的問題解決能力,大幅度降低問題改善時間與實驗驗證成本。 關鍵字:田口實驗設計、六標準差DMAIC,蝕刻薄化,生物(指紋)識別
Nowadays, the increase in screen ration for smartphones has become one of the selling strategies for phone makers. Implementation of larger and thinner biometric (fingerprint) recognition component has become a challenge for biometric solution providers. This paper studies the variation of ultrasonic biometric sensor TFT glass before thinning (500um) and after thinning (90um), as one single TFT glass contains more 500 TFT chip. The uniformity of TFT after thinning is very critical to the whole process. The variation in thickness of TFT glass will result in glass edge cracking or chipping during breaking or in on-going process. This, in turn, will affect the sensor function in some level. The uniformity in TFT glass thinning is a challenging process. This paper applies Taguchi method, six sigma and DMAIC methodologies to define the scope and key characteristics of problems and evaluate data from different stages. Taguchi method is applied to design minimum DOE, evaluate factors and level to retrieve the best parameters of thinning process. Then effectiveness through process monitoring is confirmed. This paper applies “scientific-Taguchi” and “systematic-six Sigma, DMAIC” to analyze method and implement them in case study company to improve problem-solving in time reduction and cost saving. Keywords: Taguchi method, Six Sigma, DMAIC, chemical etching and biometric (fingerprint) recognition