品質成本制度是使管理者了解公司過去在品質提昇之努力所投入的成本,以及因品質不良而總共付出的代價,並藉由這些品質相關的資訊來做適當的決策進而提升品質。 本研究採六標準差以成本節省導向(saving-oriented)的改善模式作為降低品質成本的考量。由於韌體品質的定性特性,本研究於六標準差分析階段使用失效模式與效應分析(FMEA)量化韌體的品質特性,以取得對韌體品質具有顯著影響的控制因子。此方法依照個別控制因子的影響程度作為資源投入順序的參考並觀察關鍵製程輸出的降低來確認找到的是關鍵影響因子;除了在資源投入後觀察其發生頻率的降低來評估其品質的提升外並監控其穩定性。 本研究以案例公司施行六標準差差結合FMEA方式改善品質的成果,討論此方法運用於案例公司韌體品質成本改善的成功因素與後續的推廣。最後並將此降低韌體品質成本之方法整理為系統化之流程,作為後續應用之參考。
Quality cost management system makes quality as quantified information to let top management understand the total cost due to resources spent for quality improvements and penalties for poor-quality. Base on this quality cost information, top management can make proper decision to improve quality. This research adopts the six-sigma analysis with saving-oriented improvement approach to reduce quality cost. Due to the qualitative characteristics of firmware quality factor, this study uses Failure Mode Effect Analysis (FMEA) method to quantify the firmware quality factors during six-sigma analysis phase. This method assesses the impacts of individual quality control factor to determine the priority of input resources to for improvements; and monitors the reductions in the frequency of occurrences, to evaluate the level of improvements and to assure their stability. Base on the results of a case study, this research discusses the success factors and future use of the six-sigma/FMEA-based quality cost reduction methodology. In the end, this research summarizes the methodology in a formal process for improving firmware quality.