在高電漿密度蝕刻機中SF6電漿分解產物對產品的影響與研究

Abstract

本論文研究分為兩大主題: 第一個主題是研究SF6電漿分解產物所污染的環境對金屬腐蝕所產生的影響。由實驗中得知經過SF6電漿分解產物所污染的晶圓盒，容易對金屬產生腐蝕作用。在IC製造的工廠中，金屬腐蝕所造成的產品品質問題常常困擾著許多人。而如何造成金屬腐蝕及如何解決也是眾說紛紜。因為金屬腐蝕常常發生在不固定的地方及不固定的時間，也沒有規律性可言。本研究發現金屬腐蝕來自SF6電漿分解產物所污染的晶圓盒。SF6電漿分解產物中的SF5 或 SF4 容易吸附在晶圓盒的表面，與空氣中的水氣反應後產生腐蝕性的氫氟酸，氫氟酸非常容易與鋁金屬反應形成三氟化鋁。 所以晶圓承載盒在晶圓製造的過程中常常是污染源。

第二個主題是研究在雙源電漿蝕刻機中，SF6電漿分解產物形成半透明的六角形微粒污染晶圓。而化合物“F11NS2” (or (F5S)2NF) 是最有可能的生成物，具有揮發特性。在雙源電漿蝕刻機中，SF6電漿分解產物中的SF5 與三氮化矽形成化合物，附著於晶圓表面。而加入氧電漿於蝕刻後可有效去除此種微粒，因為氧電漿可以有效的降低SF5 的濃度，進而降低微粒的形成。

最後結論，我們探討的主題放在未來要如何避免蝕刻副產物所造成的晶圓交互污染。利用各種設計，來降低所有可能的污染途徑。有許多的想法已經施行於現有的機台上許多年，且得到很好的成果。

In this thesis, there are two topics of SF6 decomposition products of DPS poly etcher in IC’s manufacturing to be studied. One is the study of metal corrosion in an environment contaminated with SF6 decomposition products. The other is the study of contamination of SF6 plasma decomposition in DPS poly dry etcher.

The first topic is about the corrosion metal. It was found interesting that the metal corrosion have strong correlation with environment contaminated with SF6 decomposition products. In IC’s manufacturing, the corrosion metal appeared sometime and somewhere, the period was irregularly, and suffered many companies for a long time. The corrosion Al-Cu film is caused by SF5 or SF4 of SF6 decomposition. SF5 or SF4 absorbs on the surface of box and react with moisture. HF is existence on the boxes, attacks metal film and causes corrosion metal.

The second topic is the reduction of semi-translucent hexagonal defect from SF6 decomposition in DPS poly etcher. The “F11NS2” (or (F5S)2NF) is the most possible compound of the volatile residue. Semi-translucent hexagonal defect was formed on nitride wafer in DPS poly etcher with SF6 plasma. Adding O2 plasma treatment in the end of poly etching is the best solution to remove particle. O2 plasma treatment can decrease of SF5, and then decrease of F11NS2.