於擴散區加入控片考量派工模式之構建

Abstract

半導體晶圓製造為目前國內最具競爭力之產業，然而由於晶圓製造本身複難之製程牲性及機臺特性，以致造成其在生產管理上的困難。目前與晶製造生產排程相關的文獻，其所探討之投料派工法則，大多只侷限在如何針對瓶頭機臺以及非瓶頭機臺不同的特性來發展更完善的法則，又或者只是針對不同的機臺牲性發展能提高生產績效的法則而已；其中卻從未有文獻控擋片在生產過程中所扮演的角色。控擋片雖屬必然的消耗品，然而對現今之八吋晶圓廣而言，雖然技術與產能提高了，但對控擋片而言，其所需成本亦相對大幅提高，因此若未對控擋片做適當的管理，則可能導致控擋片未能充份利用，使現場充斥控擋片在製品存貨，而造成成本的浪費與資金之積壓。 由於擴散區之爐管機臺的加工時間長，而且在控擋片的使用較為複雜且頻繁，因此在本研究中吾人針對擴散區之生產特性配合控片之生產以及其被使用之時機、數量，建立一於擴散區中加入控片考量之派工法則，以期有效降低控擋片在晶圓製造廠的WIP量。

Semiconductor manufacturing is the most competitive industry in our country now. It is difficult to manage the wafer production procedures because of the complexities of the corresponding manufacturing processes and machines Most past research papers emphasized the dispatching procedures for bottleneck and non-bottleneck machines. They tried to develop better rules to improve the production performance. However, none of the papers put emphasis on the role of control and dummy wafers in wafer fabrication. Generally speaking, WIP, throughput, due-date, and cycle-time are key indices chosen to measure the performance of a fab. Good performance requires stable process conitions. Dummy wafers and Control wafers are responsible to stabilize and control the process. Dummy wafers and Control wafers are consumer goods. But the cost of those wafers increases when wafer size comes from 6-inch to 8-inch. It is necessary to make some procedures to properly manage the dummy wafers and control wafers to save money for wafer fabrication companies. In this research, we designed a dispatching procedure to take management of control wafers with the following two constraints: (1) The production of control wafers cannot affect the manufacturing of normallwafer lots, (2) The delay of production normai wafer lots due to the lack of control wafers should be avoied. Because control wafers usually consume a great amount of capacity for the pre-deposition processes at the diffusion area to be used at the immediate downstream equipment (eg. etching ) we develop a dispatching procedure for diffusion area with a deep consideration of the above two constraints. Results show that the proposed dispatching procedure is effective for a simplified real fab.