ANAHEIM, CALIF. — Plastics, primarily epoxies, are replacing ceramics in top-of-the-line substrate-carrier packaging for microprocessors.
While ceramic packaging has been backsliding for years, production remains high, in part because of price concessions.
``The drive is to plastic,'' academician CP. Wong said at Nepcon West.
``Intel still puts the Pentium Pro in hermetic ceramic, but the plan [is] to go to plastic because of low dielectric constants [and] thermal issues,'' he said.
Wong is a professor at Georgia Institute of Technology's school of materials science and engineering in Atlanta and a former AT&T materials guru.
Production of molding compound has stagnated, however, despite dramatic growth in the number of microprocessors. Smaller components, reduced waste and better manufacturing processes have flattened production volumes for a decade at key Japanese suppliers Nitto Denko and Sumitomo Bakelite Co.
Use of plastics for packaging tips the scale toward U.S. suppliers. Materials include epoxy, polyimide, polyxylylene, silicone and benzocyclobutene.
In June, Intel Corp. of Santa Clara, Calif., introduced the first of a Pentium processor series ``housed in a new, more thermally efficient plastic pin grid array package,'' according to the firm.
Intel is the largest supplier of microprocessors and other semiconductor products to the computer industry.
The industry is ``moving [away] from ceramic and hermetic and expensive and 20-year-life'' military requirements, said Steve Anderson, vice president of corporate product marketing in Chandler, Ariz., for Amkor Electronics Inc. ``All they need is three to five years'' for the small, hand-held personal computers, telephones and digital cameras in the consumer market.
Amkor ``did a lot of ceramic in the past,'' Anderson said, but now uses ``some kind of plastic or tape-based product.''
West Chester, Pa.-based Amkor makes silicon memory chips and programmable arrays, mostly at four factories in South Korea and three in the Philippines.
``Because of commercial industry's almost-exclusive, 97 percent use of plastic for microcircuit packaging, the availability of ceramic alternatives is dwindling,'' research scientist Patrick McCluskey said in a telephone interview.``This lack drives the use of plastic packaging in low-volume, high-reliability applications such as avionics, automotive electronics and even military electronics,'' McCluskey said.
Advances in molding compounds and techniques give plastics ``the needed performance and reliability and provide significant competitive advantage,'' McCluskey said.
He operates at the University of Maryland's electronic packaging research center in College Park, Md.
``Plastics is being used for high-frequency applications'' and ``has replaced ceramics,'' said Scott Trevino, technical marketing manager for Ibiden USA Corp. in Santa Clara, Calif.
Japan-based parent Ibiden Ltd. makes multilayer epoxy-based packages for microprocessor and ASIC applications for work station and personal computer markets.
``Traditionally, many [high-end] packages have been made of ceramic,'' said Bryan Anderson, applications development manager with Dexter Corp.'s electronic materials division in Industry, Calif. ``Technology was not available in the [substrate] industry to get the fine lines and spacings that are required of the wire bonding process to that substrate or chip carrier package.''
Anderson believes the ceramic industry is cutting prices although questions remain about whether ``they are as low as people think they are.''
The dominant ceramic supplier is adjusting.
``Even the Kyoceras of the world are going over to plastics because they have to,'' Anderson said.
Kyocera Corp., based in Kyoto, Japan, holds about 65 percent of the world market for ceramic packages.
According to Kyocera's 1996 annual report, the technical ceramics manufacturer is ``developing high density multilayered printed wiring boards that use new production processes and materials combining plastics and ceramics to provide the best features of both organic and ceramic materials.''
Cutbacks have occurred. Aluminum Co. of America closed its electronic packaging subsidiary in early 1996, laying off 1,200 workers in San Diego. Its largest customer, Intel, had curtailed orders for Alcoa's ceramic packages for semiconductors in the move to plastic.
In late 1996, Microelectronic Packaging Inc. trimmed ceramic package operations in San Diego and Singapore. Movement to plastics packaging was blamed.
``We are seeing thermally and electrically enhanced plastic packages that now meet some of the same performance requirements,'' said Greg Johnson, director of sales in Palo Alto, Calif., with Asat Inc.
Cellular and high-performance applications fit the mold.
``Before, customers had to go to a multilayer ceramic for the same performance,'' he said.
Asat, a unit of QPL International Holdings in Hong Kong, uses only plastics in making surface mount products.
Merix Corp. in Forest Grove, Ore., is among firms trying to manufacture substrates in the United States.