By John Rhea
SACRAMENTO, Calif. — The Defense Microelectronics Activity, or DMEA, is poised to activate its own "flexible foundry" later this year at McClellan Air Force Base in Sacramento, Calif.
The DMEA foundry is to make small batches of the types of integrated circuits that the semiconductor industry has abandoned, particularly 5-volt devices now that the industry is moving toward 3.3 and lesser voltages.
Operations are due to begin in December using the bulk complementary metal oxide semiconductor (CMOS) process at feature sizes of 1 micron, reports Douglas Casanova, chief of the microelectronics technology branch at DMEA. Plans call for moving down in size to 0.6 micron by the end of next year.
The long-term projection is for feature sizes down to 0.35 micron by 2001 and adding other processes, including dielectric isolation radiation-hardened bipolar, and eventually silicon on insulation to be licensed from Intersil Corp. (formerly Harris Semiconductor) in Melbourne, Fla.
The effort is part of the U.S. Department of Defense`s diminishing manufacturing sources (DMS) program, which also includes cooperation with industry associations and aftermarket suppliers to ensure the availability of integrated circuits needed for weapon systems.
Not only is the commercial semiconductor industry unwilling to produce these parts for the relatively low-volume, long-product-cycle military market, but military officials consider the cost of redesigning their systems to accommodate the new 3.3 volt parts to be prohibitive.
The 5,100-square-foot DMEA wafer fab consists of 2,100 square feet of supporting facilities and four production modules (all in class 10 or 100 clean rooms) totaling 3,000 square feet, Casanova says.
The modules are organized into four functional areas: (1) lithography; (2) wet etch; (3) stepper and dry etch; and (4) diffusion furnace and ion implanter. The functions will embrace digital and analog technologies, ranging from personalizing devices and gate arrays to full custom fabrication of applications-specific integrated circuits (ASICs) at a complexity of more than 500,000 gates, operational amplifiers, voltage-controlled oscillators, and analog-to-digital converters.
This is not the three-shift, seven-days-a-week wafer fab of the commercial industry, adds Gary Gaugler, a consultant to DMEA. The plans call for initially running 10, 15, or 20 wafers a week, five wafers to a lot, with the eventual capacity of 100 wafers a week. These are 4-, 5-, and 6-inch wafers, he adds, and DMEA will essentially buy the wafers and then add the various metallization layers. Gaugler estimates the total cost of the facility at about $10 million.
DMEA officials are quick to point out that they have no intention of competing with commercial industry and that the primary thrust is to tackle the DMS problem and satisfy quick-turn around requirements. In fact, DMEA is working with device suppliers under cooperative research and development agreements, or CRADAs, to transfer their technology, says Ted Glum, the director of DMEA. The new facility will provide parts for all the services` electronics operations as well as the Defense Supply Center Columbus in Columbus, Ohio, and will develop guidelines for the use of commercial off-the-shelf, or COTS, products, Glum says.
The DMS problem is thornier than the simple reluctance of commercial makers to pay attention to the military market, Gaugler explains. Custom ASICs are not second sourced, he says, and last year lower voltage devices exceeded the volume of 5-volt devices for the first time. "Shortly, 5 volt device technology will be gone," he comments.
Yet the military depends on 5-volt devices. Not only is the redesign cost prohibitive, but also many of these systems are software-based and the cost of requalifying the software "just makes the prospect that much more bleak," in Gaugler`s words. As a result, he says, "DMEA becomes the last source of supply for military parts from that [5 volt] process."