建立以品質導向為主之積體電路離子植入的製程之派工指標

Abstract

在積體電路的製造裡, 離子植入的製程，影響晶片的品質甚大. 在過程中,由於機器的陰極靶在加熱的時候, 陰極靶的電阻直徑，會因不同處方或增加或減少. 因而改變電阻係數, 也因而製造出不良品質之晶圓. 因此, 離子植入製程之派工指標不僅要縮短加工作業時間和滿足交貨期,更要確保機器的加工狀況，製造出優良品質的晶圓。 本研究主要目的在於提出一個以品質導向為主之積體電路離子植入製程之派工指標. 所提出之派工指標不僅考量縮短加工作業時間與滿足交貨期, 尤其確保機器的加工狀況. 在本研究中，所有等待加工之線上晶圓批的派工指標會即時被估算出，獲得最大之派工指標的晶圓批將被選擇為下一批最適加工的晶圓批。為了與其它派工指標比較，除了建立以品質導向為主之派工指標, 同時建立了比例組合優先派工指標和混合優先派工指標，此三種指標將在本研究中被深入的討論與比較。 為了探討不同情境下之三種指標的表現，本研究擬採用模擬的方式來達成，因此單機器的模擬模式被建立了。三個績效指標，即加工作業時間、交貨期與機器的加工優良狀況，將被用來評估兩種不同的具體方案。 模擬結果顯示品質導向為主之派工指標的確可確保機器的加工品質, 在加工作業時間與交貨期上的表現，亦優於或相似於其它兩個指標.

The ion implantation process in the IC fabrication is one of the most important steps that determine the wafer quality. During the process, the filament in the equipment is heated, and the resistance of the filament decreases or increases depending on the recipes processed. Equipment with too large or too small resistance of the filament may produce unacceptable quality wafers. Therefore, not like the dispatching scheme for the other IC fabrication processes, the scheme for an ion implantation process must consider not only the minimum total process time and due dates but also the machine operational quality condition. This research proposes a quality-based job dispatching index for the IC ion implantation process that minimizes the total process time and meets due dates, as well as improves the equipment operational quality condition. In an on-line look-ahead base, the quality-based job dispatching index for all work in process jobs are estimated, and the jobs with the largest index is picked to be processed next. For the comparison purpose, besides the proposed quality index, two more job dispatching indexes with a recipe mix priority and a joint priority are established, respectively, in this study. A single machine simulation model is established, and used to evaluate the three indexes under two specific scenarios. The simulation results provide insights about the implementation of the quality-based index, and demonstrate the quality-based index can achieve the goals better than the other two indexes.