Best Practices in Semiconductor Manufacturing
This is a no-revenue generating web site.
Robert C. Leachman and David A. Hodges of UC Berkeley have several studies on best-practices related topics in the semiconductor industry. The notes on this page are excerpted from a published paper. Before that, R. Hayes (Harvard) and S. Wheelwright (Stanford) wrote a book entitled "Restoring Our Competitive Edge: Competing Through Manufacturing" (1984) summarizing their research findings on competent manufacturers in general - it is not surprising that there is a convergence of ideas from all researchers.
The interested reader might want to visit the Competitive Semiconductor Manufacturing Program web site for technical reports and on-line resources. Also, some engineering departments offer classes on Industrial Engineering and Operations Research (IEOR) related to semiconductor manufacturing as Dr. Leachman's course #130 entitled: "Methods of Manufacturing Improvement".
Notes:
(1) A tremendous amount of planning and effort had gone into creating the environment that culminated in organizations that are efficient and productive. This would entail the coordination of Corporate Quality, the different engineering functions, and Human Resources.
(2) Reasons for the success of best performers are: training and documentation.
Background
 |
Robert C. Leachman and David A. Hodges compared the manufacturing performance of semiconductor wafer fabrication plants in the US, Asia, and Europe. Detailed comparisons over multi-year intervals show that important quantitative indicators of productivity, including defect density (yield), major equipment production rates, wafer throughput time, and effective new process introduction to manufacturing, vary by factors of 3 to as much as 5 across an international sample of 28 fabs. | ||||||||
|
|
Rates of improvement were studied for each participant. Scores for each technical metric were computed for each quarter over a period of three to four years. | ||||||||
|
|
The authors identified
important factors in the areas of:
|
that correlate strongly with high productivity. Optimum manufacturing strategy is different for commodity products, high-value proprietary products, and foundry business. Performance and practice comparisons are separated into VLSI memory, VLSI logic, and MSI categories, according to the type and sophistication of devices that are fabricated.
Operational Practices that Underlie Leading-Edge Manufacturing Performance
Robert C. Leachman and David A. Hodges define nine basic themes for key practices that underlie leaders' performance. These themes are:
Operational Practices
A. Human Resources:
|
|
Leading fabs have strong internal technical talent complementing support from vendors to expeditiously modify product, process, and equipment to implement changes that have been identified by problem solving efforts as desirable or necessary. In particular, leading fabs have considerable in-house equipment engineering talent, identifying and implementing useful modifications to process equipment that improve performance or ease maintenance. In contrast, weak-performing fabs have process engineering organizations that are virtually devoid of equipment engineering skills. |
|
|
The leading fabs have instilled problem-solving skills in their technicians and operators through extensive training, mentorship and participation in continuous-improvement teams. Thus, these fabs are very good at problem recognition, problem solving, and elimination of repetitive problems. |
|
|
Reducing division of labor involves training efforts and job expansions to reduce response time to problems and to promote more effective formulation of engineering solutions. Operators at leading fabs are trained to perform basic equipment maintenance and trouble-shooting. |
|
|
Technicians and operators work together in leading fabs on continuous improvement teams. Such teams identify and research process and equipment problems, find root causes, and then devise, test and implement permanent fixes. The teams serve to expand the knowledge, skills, confidence and job scope of all personnel. |
|
|
The division-of-labor theme also applies to engineers. Process and equipment engineering groups are merged in leading fabs, broadening the skills of engineers and promoting quicker identification and implementation of effective solutions to process and equipment problems. |
|
|
Thus manufacturing has a major engineering aspect as well as the expected operational character. This means a fab must continually develop technical competence of its organization and continually foster a teamwork approach to recognize problems, devise innovative solutions, and implement them quickly and successfully. |
B. Management of New Product Introduction:
|
|
Leading fabs have effective procedures for managing the introduction of new process flows. The economic life of many process flows is three to four years, with unit prices for products of the flow declining rapidly over this period. Thus it is economically important to realize high productivity quickly after process introduction, and to fairly frequently introduce new process flows. A poor start with a new flow may leave the fab too far behind to catch up before the market value of the output has declined. |
|
|
The leading participants strategically stagger transitions to new product generations and new process generations, and control the number of new modules in each process generation to keep the difficulties at each step to a tractable level. The leading participants also have effective operational procedures for new process transfer. |
|
|
Identical equipment sets are used in development and in production; development and volume production are often co-located. Transfer of process documentation is electronic. Engineers from the recipient manufacturing fab participate in the final stages of development. |
|
|
In cases where a fab scored poorly for certain metrics, the most common reason was that the relevant area was simply not a focus of the fab management. Every participant has certain focus areas that management impresses on the work force as top priorities for improvement; associated with each area is a paradigm for data collection, problem-solving, training, etc., that we call a culture. We use the term culture because of the management efforts clearly made to rally the organization around a unifying theme aimed at improved performance. |
This site was last updated 07/11/10
© 2009 Stephen Hyatt
Web Site Administrator Novella Web Design