危害分析應用於製程持續改善之研究 －以高科技產業矽甲烷混合氣供應系統為例

Abstract

本文擇定「危害分析應用於製程持續改善之研究—以高科技產業矽甲烷混合氣供應系統為例」為題，嘗試就目前產業界常用的危害分析方法，探討其特性、適用時機及優劣點，並以高科技產業10% SiH4＋N2混合氣體供應系統為例，於其製程變更前、後，及運轉維護等各階段，分別以各種分析方法實施危害分析，藉以辨識並消減其潛在危害，比較變更前後之安全效益，貫徹製程「持續改善」核心理念。 本案例製程原採用49 liter鋼瓶裝10% SiH4＋N2混合氣，置於傳統氣瓶櫃中，再以雙套管將混合氣送經VMB，供應後段製程設備使用。由於生產規模擴充，SiH4混合氣需求量呈倍數增加，不僅既有氣體房之空間不敷使用，更換鋼瓶作業之頻率亦將等比增加，作業危害風險大幅提升。經仔細的規劃及經濟效益評估後，決定改採大型供應的模式，使用Y型鋼瓶供應100% SiH4，另由液氮儲槽供應氮氣，並於氣瓶櫃中設置混合器，逕行產生10% SiH4＋N2混合氣體，供應製程之需求。製程變更方案確定之後，先以Check list實施初步危害分析，顯示新製程具有重大潛在危害，爰再使用HAZOP執行細部危害分析，再於HAZOP分析所得之改善建議執行完竣後，採用FTA實施第三度危害分析，以比較製程變更前後之安全效益；新製程進入運轉維護階段後，則以Check list執行定期稽核，確保製程設備、安全設施與管理維持於初設置之水準，以消弭產業災害，達成產業永續發展之目標。

This paper, entitled as “study on the application of hazardous analysis in the constant improvement of process – as in the case of high-tech industrial silane mixing gas supply system”, attempts to study the characteristics, times to use, advantages and disadvantages of the methods of hazardous analysis commonly used in the present industry. The hazardous analysis is applied in the case of high-tech industrial 10% SiH4 + N2 mixing gas supply system, we use various analytical methods in turn, at the stages before and after the change of process and of the operation maintenance, to perform the hazardous analysis, by which we can identify and diminish the potential hazard, and reveal the radical idea of “constant improvement” of process by comparing the safety efficiencies before and after the change.

The original process utilizes the 49 L cylindered 10% SiH4 + N2 mixing gas, which is placed in the gas cabinet, and the mixing gas is delivered through VMB by the double tube, then used in the back sectional process equipments. But, due to the expansion of production scale, the need of SiH4 mixing gas is increased by times, so that not only the space is not enough to place the cylinders, but also the frequency of replacing cylinders is increased proportionally, that will raise the risk of operation hazard largely. After the detailed project and the evaluation of economical efficiency, we decide to adopt the other large-scale supply system, i.e., using the Y type cylinder to supply 100% SiH4 and the liquid nitrogen tank to supply the nitrogen, then mixing them in the mixer located in the cylinder box, to produce the 10% SiH4 + N2 mixing gas for the need of process. Having confirmed the project of changing process,

Check list is used to perform the initial hazardous analysis firstly, and it reveals the new process has the significant potential hazard, secondly, HAZOP is used to perform the detailed hazardous analysis, then, after the completion of improvement based on the suggestion obtained from the HAZOP analysis, FTA is used to perform the third-stage hazardous analysis for the comparison of safety efficiencies before and after the change of process. Once the new process is at the stage of operation maintenance, Check list is used to perform the regular check, to assure the process equipments, safety facilities and management can be kept at the level of initial setup, and then, to prevent the industrial damage and reach the goal of permanent development of industry.