半導體供應鏈後段製造廠之在製品管理模式

Abstract

對於面對競爭日漸激烈且日漸全球化的半導體供應鏈而言，顧客所訂購產品之準時達交與否，決定了顧客對其服務是否滿意、是否願意繼續維持合作關係。半導體供應鏈中，同時擁有針測、封裝、最終測試之後段製造廠較前段的晶圓廠接近最終顧客端，肩負起是否能夠將產品準時達交到顧客手中的責任。後段製造廠決定整條半導體供應鏈的顧客滿意程度，然而由於它的生產週期時間較晶圓廠短，能夠對生產活動中不可避免的生產變異（如當機等）採取反應措施的時間因而也較短。因此，後段廠中的生產變異對半導體供應鏈之產品準時達交與否有一定程度以上的影響。 實務上，最常利用調整在製品(WIP)水準的方式來降低生產變異對產品交期的影響以及保護產出，因此，本研究提出一套在製品管理模式，幫助後段製造廠有效能夠地管理在製品，以降低生產變異對工廠的影響，進而提高全廠、全半導體供應鏈之產品達交績效。 本研究之在製品管理模式包含三大部分：(1) 可允許在製品變動水準（Acceptable WIP Deviation Level，AWDL）決定模式，可利用此模式訂定出各工作站之合理在製品水準。（2）在製品修正措施：一旦在製品水準超出AWDL，可利用在製品修正措施，以最快的速度修正在製品水準回至訂定之AWDL。（3）例外管理系統：構建一即時監控在製品水準之例外管理系統，以監控在製品是否超出訂定之AWDL並通知相關人員。

The agreement of due dates is the need for customer satisfaction, which is a critical factor to survive in today’s highly competitive market for Semiconductor inductry. However, undesirable and inevitable production variations make it difficult to maintain and improve factory’s performance on due dates, especially for those back-end factories closer to customers. We, therefore, propose a WIP management model to help production managers effectively manage WIP levels to compensate the impact of unexpected production variations and to achieve better due-date performance. The WIP management model can be divided into three parts: (1) an AWDL (Available WIP Deviation Level) determination model is designed to gather proper AWDLs for monitored workstations, (2) a WIP correction action is proposed to make abnormal WIP levels back to normal levels as soon as possible, and (3) an exception management system is constructed to detect WIP exceptions and notify pertinent recipients. Simulation experiments are conducted to evaluate the proposed WIP management model. Results show that WIP management model provides back-end factories better performances on average on time delivery percentage (AOTDP). The model does help back-end factories to manage WIP levels effectively and reduce the occurrences of production variations.