| Summary: | 碩士 === 中原大學 === 工業工程研究所 === 102 === This study applies a combined research of Six Sigma and IDEF0, based on the DMAIC model to improve the chemical A process of chemical industries. The customer demand triggers this study to find out a better way to improve the process than the original process does. Six Sigma is the main frame for this study for using quality tools and statistic methods to find the root cause and do analyses for the process.
The modules of analysis are as follows:
(1) Define phase: Chemical A is the raw material of wet chemistry, the usage of which is higher than other chemicals. This company produces chemical A for semiconductor customers. Recently, under the requests from a customer, the chemical A particle with 0.05μm has to be controlled within 30 pcs/ml for a specific advanced production process. Consequently, my company set up a project team to improve the quality of chemical A process, which based on particle sizes to be a key quality characteristic. In this phase, team members learn and understand the process by using IDEF0 too easily. Through IDEF0 and brainstorming, we find some impact factors that could affect the particle amount, and then make a cause-and-effect on diagram. Finally, C&;E Matrix is used to converge the factors.
(2) Measure phase: Define the factors of convergence, and check the method of how people do sampling. We carry out sampling particle, and find out the result of samples to know the population characteristics. Because the sampling in this study is a kind of destructive test, so that we use variance analysis to verify the methods of sampling.
(3) Analysis phase: Base on the result of process checking, we find out the root cause comes from the design of the filter, and through the method of experimental design, we find out another root cause comes from the cleanliness of the bottom of lorry.
(4) Improve phase: Base on the results of the analysis, we improve the issue of the design of the filter. Taking the cost into consideration, before the chemical filling, we add a new process to use 100L chemical A to clean the lorry inside. Finally, we check the action is effectively or not by analyzing the trend chart and box chart.
(5) Control phase: Finally, we use the I-MR chart to control the cleaning process of the lorry, if the result does not match with the standard, then we have to re-work. This action is to ensure the quality of chemical A particle can comply with the demand of semiconductor customer.
Through the verification of the case study, the chemical A’s particle is reduced from 109±58 pcs/ml to 18.52±8.8 pcs/ml, which could fulfill the requirement of customers. This improvement of performance indicates that Six Sigma combined with IDEF0 works and that could be used for other industries as well.
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