半導體IC代工產品製程技術之碳足跡分析

Abstract

半導體產業的IC(Integrated Circuit)產品為市售各種電子產品的重要零組件，被廣泛地應用於電腦、通訊、消費性電子、工業電子等諸多用途。歐盟FP7科研架構計畫(LCA to go計畫)更指出在極端案例下，IC產品的碳足跡約佔電子產品碳足跡之三分之一。本研究以晶圓代工半導體廠為例，以現行完成之產品碳足跡結果為基礎，彙整收集產品生產過程的製造程序、參數等資料，結合碳足跡盤查方法的分類項目，整理出以近似準確的方式分配原本的產品碳足跡平均值，有別於以往當年度同廠區的產品碳足跡皆為定值的呈現結果，而可以依產品類別及製程複雜度呈現當年度同廠區每一個產品的碳足跡值。 研究結果顯示，晶圓代工產品碳足跡的主要排放來源為製造階段的電力使用排碳量(64%)，其中維持無塵室環境與製程生產的用電量比例為1 : 1，足見廠務系統及生產機台節能設計的重要性；在生產製程的碳排放權重貢獻依序為擴散、蝕刻、薄膜及黃光製程，除薄膜製程的主要碳排放來源為使用高溫室氣體潛勢的PFC氣體外，其他的主要排放量來源則是機台使用電力的排碳量；另在產品製程參數的關係分析結果顯示，光罩層、蝕刻層數與產品碳足跡呈現正相關，製程技術則與碳足跡呈現負相關。本研究結果可以應用於產品設計階段，企業若考量與產品碳足跡的排放相關因子，將有利於落實環保意識。

Integrated Circuit (IC) products in the semiconductor industry are important components of electronic products on the market, and are widely applied in the areas of computers, communication, consumer electronics and industrial electronics. Based on an extreme case of the LCA to go Plan in the EU FP7 Framework Program, the carbon footprint of IC products could make up one-third of carbon footprint of all electronic products. This study intends to differentiate the process procedure and parameter based carbon footprints and find out the process or operation parameter which contribute most to the carbon footprint of the IC foundry. The results show that the major contribution of carbon footprint was from electricity used in the manufacturing phase (64%), among which the proportion of electricity used to maintain the clean room environment and the production process was about 1:1. The carbon footprints in the production processes are in the order of Diffusion> Etching> Thin Film> Lithography process. For these four processes, the Thin Film production process used PFC gases which has high-GWP and thus PFCs contributed most to its carbon footprint. The other three processes had the same major emission source of electricity uses. For the result on the evaluation of process parameters, it is observed that the mask layer and etched layer were positively correlated to the carbon footprint, while the process technology was negative correlated to the carbon footprint. The results can be provided for the Eco design of IC product and help to reduce the carbon footprint.