UA’s HighDec Continuing to Make Electronics Smaller

On the south side of Fayetteville, research is under way that will further reduce the size of electronics.

“The whole goal of electronics is to make things smaller, faster and cheaper,” says Leonard Schaper, director of the University of Arkansas High Density Electronic Center. “There is more technology in your CD player [today] than there was in your computer 10 years ago.”

Many companies focus on the development of computer chips, but HiDec concentrates on improving the complete package.

“The packaging has not advanced as fast as the chips themselves,” Schaper says.

Wiring, referred to within the industry as “packaging,” takes up most of the space on a traditional circuit board. The center’s researchers find smaller and more efficient ways to package wiring and computer chips to produce more reliable, efficient and inexpensive pieces of electronics.

Most boards use four layers of wires and conductors, but HiDec recently has created a new design using only two layers. The result is a multichip module much smaller than the current industry standard. HiDec has patented both its design and creation process for the new module.

The design, named the Interconnected Mesh Power System, or IMPS, is being manufactured by MicroModule Systems of Cupertino, Calif. As other companies use the technology, the university will receive royalties from the design.

The new modules are created in an eight-step process that forms wires on a silicon wafer. The process uses diluted acid to etch portions of the wafer and create a pattern of layered aluminum wires. The wires are 2 micrometers thick, or about 1/30 the width of a human hair.

When complete, the entire module package measures 54 millimeters by 49 millimeters and is only 3 millimeters thick.

“One of the problems with this very high density interconnect is making it on silicon wafers is not the best way to build this stuff,” says Schaper. “If we could make it bigger, and square, we could put more modules on there, but the amount of handling would be the same.” The result, he explains, is a drastic reduction in cost.

The center currently uses a 5-inch wafer, although most companies now use an 8-inch wafer, and a 12-inch model is currently being developed. HiDec’s research is applicable to each wafer size.

The new design has a staggering array of implications, and one of the applications that the center is investigating is related to motor speed control.

“This country has an amazing amount of electric power, but a lot of that power goes to running motors, and a lot of times they do not need to be running all of the time,” explains Schaper. “There is a strong push from the [U.S.] Department of Energy to create some technology that will intelligently control motors.” He says the motors range from large machines to household refrigerators. The center is currently in discussions with several companies, including Baldor Electric of Fort Smith, to apply the technology to this problem.

Schaper will speak about the center’s multichip module design later this month at the Institute of the Electrical and Electronics Engineers Computer Packaging Workshop in Tsukuba, Japan. Tsukuba is home to much of Japan’s electronics research, including the headquarters of that nation’s NASA equivalent.

The other main project being developed by HiDec is also designed to shrink the packaging used to create electronics. Devices such as pagers currently use two connected circuit boards, and much of the space is taken up by passive devices such as conductors.

The center is developing a design that places all the chips in a device on one circuit board, with the majority of the passive parts on a thin layer of polyimite film referred to as flex. The film is as thin as a piece of recording tape, and when three layers are laminated together and combined with a circuit board, the design greatly reduces the size of an electronic device. The center is also in the process of obtaining a patent for the flex.

The center’s facilities are home to what Schaper refers to as “lots of fun toys” and what is probably the only “clean room” in the state.

The clean room is actually a series of laboratories where air that is 10,000 times cleaner than that of a hospital operating room. Since Arkansas does not have standards for clean rooms, the center built the complex to comply with standards set by the state of California. Everyone who enters the rooms must don protective clothing, and a series of security and warning mechanisms warn employees if materials reach dangerous levels. Inside the rooms, complex machines are used to actually create the electronics, imprint the wafers and do other sensitive tasks.

The analytical lab houses several high-powered sensory mechanisms, including an atomic force microscope, which is so powerful it can see individual atoms. The center uses the scope to detect tiny bumps or other abnormalities in the silicon wafers or any of the other materials. Even a bump as tiny as 10 micrometers wide can ruin a module. The center also has an X-ray defraction system, which is used on superconductors, and an X-ray photoelectron spectrometer, which can analyze all of the elements present in an object or on a surface.

The capabilities of HiDec’s analytical lab are available for use by area companies, Schaper says. Center employees can do private research and analysis for a fee.

Much of the center’s funding comes from the U.S. Defense Advance Research Projects division, which strongly encourages agencies it funds to form alliances with industries. Many of the center’s developments have a myriad applications for defense.

“The military has recognized they are the tail wagging the dog,” says Schaper. “They used to be the dog, but now they recognize they need to fund technological developments and bring them into the mainstream. Industries do not have the time or the money for the luxury of long-term development projects, [which is why] industry/academic partnerships are the way to go.”

One combination of efforts is the Seamless High Off-Chip Connectivity program, which involves HiDec, Cray Research, Dow Chemical Co., Integrated Device Technology and the Microelectronics Center of North Carolina. SHOCC is ultimately designed to help manufacturers by reducing the cost to mass produce electronic devices. The center has several other partnerships but is often forbidden to disclose them by confidentiality agreements. n