At A Glance
- Reduced wafer-processing cycle time by 55%.
- Customer rejects reduced 70%.
- Average Cpk value of 3.1 across all processes.
- In the last 12 months new products accounted for 75% of units shipped.
- 2,000 wafer varieties shipped in 1994.
- Lot sizes reduced by 94%.
- Total inventory and WIP inventory reduced 45% and 55%, respectively, since 1990.
- Product-development cycle time dropped 50%.
"It may look like we have a commodity product," says Jonathan Jansky, plant manager in St. Peters, "but we're far from a commodity. The science and technology associated with a wafer is significant."
That's because the St. Peters facility -- 500,000 sq ft and expanding to 550,000 -- caters to customers in the booming semiconductor industry that are forever pushing the technology envelope. "One of our customers has a sign in its cafeteria that says, 'Obsolete in 18 months,'" says Jansky. "Their product cycle is that sharp, and that comes down to us immediately."
Graham Fisher, director of manufacturing technology, says, "If we're to respond to what our customer needs, we've got to understand very clearly what the customer wants within a two- or three-year time frame in terms of manufacturing and then a three-, five-, seven-year time frame for technology."
The plant's strategic-customer quality team develops, through strategic customer interaction and annual surveys, a three-year outlook defining service and product parameters. A research-and-development planning council looks at the three- to seven-year time frame for technology-development plans. Underlying this is the plant's vision to be the best supplier of silicon wafers in the world through continuous im-provement. Employee teams have identified tools to realize that vision, the Four Cs (customer satisfaction, corporate citizenship, cost control, and culture), and six plant systems (technology, people, structures, reward, renewal, and information) that must be continuously improved to achieve the vision.
"This is an expensive business to be in," says Perry Lee, manufacturing manager. "Technology changes from day to day and from month to month. We don't know what the limits of the measurements will be, so our quality policy must be one of continuous improvement."
Quality improvement, training programs, and empowered work groups drove the St. Peters plant and MEMC to profitability, says Jansky. From 1989 to 1994 MEMC net sales have more than doubled and net income after taxes rose to $38 million. The St. Peters facility feeds 45% of MEMC's total net revenue.
The plant's quality initiatives began in the early '80s. "It wasn't a fad," Jansky says. "We put in programs that are still here today. They were part of the process, not the program of the month." The efforts began with a statistical-process-control program, and in 1985 a quality-improvement system was established to provide training."
That same year the plant switched to just-in-time (JIT) manufacturing. "Immediately, our yields went up, our inventories went down, our cycle times just crashed from 50 days down to three days, and we had some huge successes in the process," says Jansky. The plant's JIT methodology is not a rigid kanban that has to be filled, says Jansky, but one with upper- and lower-limit kanbans.
Silicon manufacturing begins when silicon ingots are grown in crucibles, pulled up by pencil-thin necks from molten silicon mixed with minute amounts of electrically active dopant. The ingots are then ground to specified diameters: 4-, 5-, 6-, 8-, and in 1996, 12-in. The ingots are sawed into wafers and the edges contoured, then they proceed through lapping, cleaning, laser marking, etching, polishing, and inspection processes. At this point a wafer can either be shipped or it goes to an epitaxial department where a thin film of silicon is grown on the polished wafer for further customer processing.
Because the plant runs 4-, 5- and 6-in. wafers over the same equipment, quick-changeover techniques, many automated, have also been established. "It literally used to take us a shift to change things out," Jansky says. "Now we can do it in just 10 minutes." The variety of wafers is also enormous. MEMC customers require various and changing parameters for their wafers -- thickness, flatness, chemical makeup, and data quality. In 1994 the plant produced 2,000 different wafer types, 90% of which did not exist three years ago.
"You've got to have a culture in the plant that's adaptive to that, and the change we've asked our folks to go through is tremendous," says Jansky. "We have 1,500 to 1,600 employees [working three shifts] in this plant, and every one of them has to have the skill to be able to make a decision, so we evolved into a team-based environment."
Brad Eldredge, director of human resources, says the plant moved toward "empowered work groups" in 1989 and seeks employees who combine high technical skills with interactive skills: "We have 56 hours of team-skills training that focuses on issues such as trust, consensus-building, win-win, confrontation, effectively conducting a meeting." Throughout the plant there is 100% employee participation in empowered work teams. Other empowered groups include a supplier-improvement team, cross-functional work teams, corrective-action teams, a policy-advisory committee, a tactical-operations committee, and total-machine-performance teams.
"Total machine performance is a component of overall total product maintenance [TPM]," says Jim Lang, operation manager of wafering. "The concept was to come up with a measurement that takes into account all the different aspects of how well a machine is performing: its uptime, cycle rate, yield, quality." One cross-functional TPM team redesigned product flow to integrate in-line inspection within the process, saving $550,000 per year in material and 12 hours per cycle.
If empowerment and quality improvements brought the plant to the turn of this century, information technology leads it into the next.
"How to convert data into information, then convert that information into knowledge -- that's really what we're striving for today," says Jansky. ". . . In 1990 we as a company realized we have two products that we make. We make the silicon wafer, but we also make data."
As wafers move through manufacturing, each customer order is traced. Operators throughout the process collect detailed parametric information and update computer documents at terminals. The system enables operators to alert engineers downstream to deviations that may be occurring, thus eliminating waste that builds up from untracked repetitive problems.
As important as this parametric data is to the plant, it's equally attractive to customers who will invest up to two months turning a wafer into chips. That's where the plant's computer information system is making an impact. It provides to the customer, via a PC and modem, an information encyclopedia of wafers as they move through production, collecting information from 20 databases.
"We need to use these data and this information as a strategic product," says Cozy Marks III, applications information systems manager. "It not only helps us improve our product but improves our means of communicating to our customer."
Jansky adds, "By having this feedback quickly and getting this information back, we identify where our weaknesses are, and we can correct them quickly."
One area at the plant where weaknesses are absolutely not tolerated is safety. "From an industry point of view we're 5.5 times better than the industry standard, so we feel very good about our safety performance," says Jansky. "An injury in the plant is a major event." The plant's safety emphasis won it the 1992 World Safety Organization's "Concerned Safety Company Award" and the Liberty Mutual Gold Award in 1993. Recognition has come elsewhere as well.
"We're getting validation of the fact that we've done some very good things over the years," says Jansky of the Best Plants award. Last year the plant won the Missouri Pollution Prevention Award, Missouri Governor's Energy Conservation Award, and the Missouri Quality Award.