- 學位論文
黃光微影製程光罩熱應力效應之覆蓋誤差改善研究
Analysis of overlay error by Reticle thermal Stress in Photolithography Process
摘要
隨著半導體製程的設計規則(Design rule)的不斷降低，關鍵層的覆蓋誤差(Overlay error)控制變得越來越重要和具有挑戰性，光罩的熱效應是造成覆蓋誤差的主要因素，近年來，陸續有提出用於光罩熱效應控制的想法和技術，並認為可以降低光罩熱效應。當深紫外光(Deep-Ultraviolet light)照射到光罩時，大部分的光線會穿過Quatz玻璃基板，一小部分將被反射回去，其餘的部分將被吸收到光罩材料中，尤其是鉻(Chrome)膜吸收熱能，光罩吸收熱能後產生膨脹，導致微影製程的覆蓋誤差，其中又以Shot Scaling (晶粒本層圖形相對前層圖形向外擴張)更是顯著。 本文以曝光量為主要影響因此，並通過實驗研究其影響。使用各種曝光量於晶圓上，比較覆蓋誤差的量測值。結果發現，即使在低曝光量的情況下，也很難避免光罩加熱。且曝光量與覆蓋誤差量測值呈現線性關係。本研究將使用熱模擬分析軟體Ansys Icepak來模擬各種曝光量的光罩受熱時溫度分布、形變分析。再利用高階補償來驗證覆蓋誤差可以被有效控制。
並列摘要
As the design rules of semiconductor processes continue to decrease, the control of overlay error of critical layers becomes more and more important and challenging. The thermal effect of photomasks is the main factor that causes overlay errors. , Have successively proposed ideas and techniques for controlling the thermal effect of the photomask, and believe that the thermal effect of the photomask can be reduced. When deep ultraviolet light (Deep-Ultraviolet light) shines on the photomask, most of the light will pass through the Quatz glass substrate, a small part will be reflected back, and the rest will be absorbed into the photomask material, especially chromium (Chrome) The film absorbs thermal energy, and the photomask expands after absorbing the thermal energy, resulting in coverage errors of the lithography process. Among them, Shot Scaling (the grains of the current layer of the grain expand outward relative to the front layer) is more significant. This article takes exposure as the main influence. Therefore, the influence is studied through experiments. Use various exposures on the wafer to compare the measurement values of the coverage error. As a result, it was found that even in the case of low exposure, it is difficult to avoid heating of the photomask. And the exposure amount and the measurement value of the coverage error have a linear relationship. In this study, the thermal simulation analysis software Ansys Icepak will be used to simulate the temperature distribution and deformation analysis of various exposure masks when heated. Then use high-order compensation to verify that the coverage error can be effectively controlled.