金屬濺鍍靶材之錐模鍛造製程

靶材是薄膜濺鍍製程之必備材料，其生產方式依照材料的性質可分為金屬與非金屬兩大類，而金屬靶則是透過澆鑄取得靶材的粗胚，再以多道次輥軋或鍛造的方式消除靶材的空孔與細化晶粒，一般而言在相同濺鍍參數的條件下，靶材的晶粒越細小、均?，濺鍍速率越快，薄膜厚度均?性越好，靶材的使用壽命也愈佳。本研究合作廠商的靶材晶粒細化是以平模鍛造的方式，經過三道次的熱間鍛壓成形製程，再經車修而得，成品會有死金屬區且晶粒組織均勻度不佳。本文將平模熱鍛改採取圓錐模鍛造以消除胚料死金屬區後，再以平模進行最終的定寸成形，可以消除靶胚的死金屬區與桶型化的成形缺陷，可達到晶粒細化與應變均勻化的效果，而且剪切帶也變的不明顯。藉由有限元素套裝軟體DEFORM-2D進行製程分析，並以等效應變不均指標與變異係數兩個指標來評價工件的變形不均勻度。模擬結果顯示，純鋁1100在250˚C下鍛壓，四種圓錐模下壓量63、69、74、80%的最佳圓錐模角度皆為12˚。相對應的應變不均勻性為平模鍛壓的0.4到0.5倍，亦即變形均勻度提升達2到2.5倍；變異係數為平模鍛壓的1/3倍，亦即變形均勻度提升達3倍，但過大的圓錐模角度會使胚料形成雙桶缺陷，導致第二道次平模鍛造產生包料現象。透過實驗驗證，以縮小1/5尺寸的商業用純鋁進行平模與最佳圓錐模角度12 ˚熱間鍛壓比較，利用維克氏硬度試驗機量取材料硬度，結果顯示圓錐模硬度不均指標數值下降了70.8%，且硬度變異係數下降40%，通過轉換硬度值與等效應變曲線擬合，證明了等效應變不均指標降低61.6%，而等效應變變異係數下降66.7%。

關鍵字

熱鍛；死金屬區；金屬濺鍍靶材

並列摘要

Grain size and its uniformity affect the deposition quality and efficiency of metal sputtering targets.Hot upsetting with flat dies has been applied to reduce the grain size however its uniformity is poor. Dead metal appears on the upper and bottom regions near the central part of the target. In this work, the cast billet was first upset with conical dies to reduce its dead metal and then followed by upsetting with flat dies to obtain the final disk-like shape. Two-dimensional finite element simulation was applied to evaluate the best parameters in designing the wedge angle and the proper amount of upsetting stroke of the conical dies. Two indices, inhomogeneity index and coefficient of variance, were used to evaluate the degree of strain inhomogeneity in the workpiece. The results show that in hot upsetting aluminum AA 1100 at 250 ˚ C, the optimum wedge angle was 12 ˚. The corresponding level of strain inhomogeneity is about 1/3 of that upsetting with flat dies. Larger wedge angles would cause dual-barreling on the workpiece and lap defects might appear in the subsequent flat-upsetting operation.

並列關鍵字

Hot forging ； Dead Metal ； Metal Sputtering Targets

參考文獻

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金屬濺鍍靶材之錐模鍛造製程

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