半導體廠建置現址式H2/N2混氣系統之可行性評估

Abstract

1997 年於京都舉行第三次聯合國氣候變化綱要公約締約大會，規定2008~2012 年間，工業化國家的溫室氣體排放量與1990 年相比至少削減5% 。因此在節能減碳的議題下，半導體產業應重新檢視氣體供應鏈之環境成本，在進行供應系統設計時，可將現有資源納入考量，評估設備投資成本及碳排放減量效益。半導體廠使用以鋼瓶為主的4%H2/N2 ，其原料供應的方式為遠隔地(Off-site) ，此方式因供應鏈冗長，當原料須經代理轉售，潛在的環境污染及經濟成本較高。 本研究主要針對以現址地(On-site) 方式配製4%H2/N2時，其對投資成本效益、抑制溫室氣體貢獻、人力資源效益、警報次數減量成果、危害與可操作性等進行研究分析。研究案例結果顯示，以每月晶圓滿載產能80K 及折舊年限20年情境下(年用氣量4,343 仟立方米)，淨現值為506,021 仟元、10 年及20 年內部報酬率分別為110.80% 及110.89% 、折現回收年限為0.94 年。另外，每年可節省86.4% 的人力資源、降低84.2% 的警報發佈量、可抑制32.4 公噸碳排放量。依據危害與可操作分析法評估製程危害結果，現址地混氣供應偏離現象為5項，相對較多組集束鋼瓶供應之7項少，因無需人員更換鋼瓶行為，故發生風險之可能性及風險等級較低。

The third Conference of the Parties to the United Nations Framework Convention on Climate Chang was held in Kyoto in 1997, it was proposed to reduce greenhouse gas emissions from industrialized countries by at least 5% during the period of 2008-2012 on a base year of 1990. In order to reduce the carbon emission, the semiconductor industry should re-assess the environmental cost of the gas supply chain. This study intends to study on the cost-effectiveness of on-site supply system of 4%H2/N2. The parameters being evaluated include the investment cost, the emission reduction of greenhouse gases, human resources efficiency, reduction of the alarm frequency as well as the hazard and operability Studies. The results indicated that under the 80K monthly wafer loaded production case and 20 years depreciation period (the annual gas consumption was 4.343 million cubic meters), the net present value was NT$ 5.06021 billion, the 10 and 20-year internal rate of return were 110.80% and 110.89%, The discounted payback period was 0.94 years. In addition, the annual savings on human resources was 86.4%, the alarm frequency was reduced by 84.2%, and the carbon emission reduction amount was 32.4 metric tons. According to the results of the assessment of hazard and operability studies, the on-site mixing gas system has a total of 5 deviation items, which is relatively less than the 7 items when using the bundle system. This is mainly due to that the on-site system doesn’t require manpower to replace the cylinder; hence it can reduce the likelihood of risks as well as risk levels.