TFT LCD製程之鉬鋁薄膜蝕刻輪廓控制

Abstract

目前市場上的TFT-LCD因生產技術的成熟，低階產品市場已呈現飽合狀況，產品規格皆往高解析度，高穿透性等高階產品發展。客戶對於面板解析度要求越來越高，如 4K x 2K、AHVA等，製程中的關鍵尺寸偏差值(CD Bias)愈來愈小，製程難度與面板品質要求將會更嚴苛，很多製程缺陷若無法即時攔檢，會造成工廠損失。 隨著近年來環保意識的抬頭以及成本下，減廢(不換酸)成為趨勢，便加入了鋁(Al)蝕刻酸濃度控制系統，降低鋁蝕刻液的更換的周期。但酸濃度與原本機台的製程參數變動與交互影響都會造成蝕刻製程中的尺寸控制更複雜，尤其是蝕刻輪廓控制很難從線上即時的檢測發現異常。對於生產周期長達4-5天TFT-LCD製程，在後段電測發現異常，常常為時已晚。此時需由電子顯微鏡來得知錐形角(Taper angle)的變化，藉此判斷異常原因，控制蝕刻輪廓的相關因子與後段良率的關係，是蝕刻工程中相當重要工作。本論文主要研究動機為探討鋁蝕刻動態參數與蝕刻輪廓角度的關係，藉由實驗設計法(DOE)來釐清重要蝕刻參數的變動與蝕刻輪廓的角度變化。目的為控制蝕刻輪廓的相關因子以提昇後段良率。

The current technology of TFT-LCD manufacturing process for general products is mature. Users are unlikely to see any major price increases in end products. As a result, the current demand for TFT-LCD is moving to high-end products, such as 4K2K and AHVA, which require high resolution and high transparency. Due to this requirement, the specifications of panel manufacturing process are upgraded. The key factors are critical dimension (CD) bias and etching taper angle. These parameters would result in the quality issues of manufactures, if they can not meet the standards and fix potential problems. The environmental awareness and cost concern are being paid close attention, so there are many new TFT-LCD manufacturing processes like aluminum acid control system. However, there is confliction between Aluminum acid concentration and variability of process parameters of the machine, thus this would lead to the complexity of dimension control, and especially etching profile control is difficult to find an exception from the online real-time detection. It is often too late in the section measurements for the production cycle of 4-5 days TFT-LCD manufacturing process. In this thesis, the motivation is to explore the relationship between the dynamic parameters of the etched aluminum etch profile angle, with experimental design (DOE) to clarify the important changes in the etching profile angle of etching parameters variation. The purpose of the thesis is to study the relationship between Aluminum etching process dynamic parameters and taper angle by DOE method in order to improve the final yield.