| 摘要: | 隨著半導體產業的快速發展、製程技術不斷的演進，使用的特殊氣體及化學品也趨於多元化，所潛在的職業危害與財產損失也愈趨複雜。Si2H6 (Disilane,二矽烷) 爐管製程，主要係利用LPCVD (Low Pressure Chemical Vapor Deposition,低壓化學氣相沉積)的原理，在高溫下通入二矽烷氣體，使矽原子和下極板之非晶矽重新組合排列，進而達到提升電容量的目的而開發的新穎半導體製程技術。 由於二矽烷爐管製程在供氧條件不佳的時候很容易產生二氧化矽、矽甲烷與氫氣的反應副產物，倘若依照業界標準的設備保養維護程序時，就有可能因為通入乾燥壓縮空氣(Compressed Dry Air, CDA)而促使管路內沉積的副產物與氧氣產生劇烈反應，而造成事故。因此本研究採用失誤模式與影響分析(Failure Mode And Effect Analysis, FMEA) 風險評估方法，分析每個製程節點在失效的狀態下的潛在危害，並搭配事件案例資料庫的方式進行嚴重度與可能性之風險評估，鑑別出相關潛在風險及特殊危害區域，並研擬有效的控制方法及改善對策，藉以提供安全的工作環境並確保人員作業安全無虞。 With the ever-increasing demands on semiconductor chips, development of advanced process technologies is vital to the success of any semiconductor company. Essentially all semiconductor manufacturing technologies use specialty gases and toxic chemicals. This presents great occupational and process hazards. For instance, a novel low pressure chemical vapor deposition, LPCVD, process uses disilane instead of silane as the process gas. This is based on the principle that the silicon atoms and amorphous silicon can be rearranged and become rough on the surface. The rough surface provides more area which can serve as the effective electrode of capacitor and hence increases the capacitance. Disilane is flammable and pyrophoric. It is extremely reactive with oxidizers and halogens. The LPCVD furnace process is prone to produce byproducts such as silicon dioxide, silane and hydrogen. If the preventive maintenance process uses compressed dry air, acute reactions might occur when condensed byproducts contact with oxygen. This study uses the Failure Modes and Effects Analysis to identify the failure mode and hazards of each process node. An event database, a collection of past events, is utilized to assess the severity and likelihood for the identified failure modes. Severity is divided into four categories such as personal injury, property and equipment damage, on-site and/or off-site impact, and chemical spill. Risk level of each identified failure mode is then evaluated based on an event’s severity and likelihood. Risk control schemes include training, standard operating procedures, engineering control and emergency response planning. Based on the acceptability of the assessed risk, a combination of the risk control schemes is used to reduce the risk to an acceptable level. For instance, to achieve effective control, both engineering and administrative control schemes are required. Results of this study prove that FMEA is an appropriate methodology for identifying potential hazards of the LPCVD process. The event database is a valuable source in providing the crucial data needed for risk assessment. The proposed engineering and administrative control schemes are effective in reducing either the likelihood or consequence of an event. |
