Opportunities Abound for Organic Packaging Materials Development

Sally Cole Johnson, Contributing Editor -- Semiconductor International, 12/5/2007 7:36:00 AM

Development of semiconductor organic packaging materials remains focused on improving performance and reliability, with the ever-present goal of reducing costs at the same time. Keeping development on track is critical, as packaging is rapidly becoming more tailored to the application of the advanced silicon (65, 45 or 32 nm).

It’s especially challenging right now because we’re experiencing a cycle in which some of the basic material prices have spiked quite a bit. “Copper prices are rising, as well as tin, gold, silver and palladium,” noted Dan Tracy, SEMI’s (San Jose) director of Industry Research and Statistics. “Suppliers are working with their customers to better manage and control consumption to get a handle on that.”

The global market for "plastic" packaging materials is expected to hit $15.5B this year, according to a new report from SEMI and TechSearch International (Austin, Texas), with the potential to expand to $20.2B by 2011. This market includes thermal interface materials (TIMs), wafer-level package (WLP) dielectrics, solder balls, die attach materials, liquid encapsulants, underfill materials, mold compounds, bonding wire, leadframes, flex circuit/tape substrates, and laminate substrates.

At the moment, laminate substrates are the fastest-growing segment, representing $6.2B of the total market in 2007. “The importance of laminate substrates is growing,” explained Jan Vardaman, president of TechSearch International. “Part of the reason is that half of the dollar value of the laminate substrate market is comprised of the flip-chip segment. It’s a more complex substrate and, therefore, commands a higher dollar value. Laminate substrates are being used for microprocessors and in PCs, chipsets, ASICs graphics and many of the high-performance devices. They’re all using flip-chip substrates. And another factor driving laminate substrate growth is DRAM has shifted away from a leadframe package [which historically was a TSOP] to a laminate chip-scale package, which is a fine-pitch ball grid array.”

There’s plenty of other ongoing activity in terms of developing new packaging materials.

“In general, many of the resins used in substrates or in encapsulants and die attach to improve moisture reliability, to lower the coefficient of thermal expansion or to modify other desirable physical properties are evolving to be compatible with low-k dielectric devices,” Tracy said.

Mold compounds, which commanded $1.3B of the global packaging market in 2007, are undergoing tailoring of mechanical and physical properties to specific package designs, package sizes and die sizes to help manage reliability and relieve stress on the die and warpage of the package. “A big trend we’ve seen in the past two years with mold compounds is with the ramp in green-compatible materials,” Tracy explained.

Speaking of greening of materials, the ball grid array (BGA) market saw a strong transition to lead-free, with ~80% of the shipments in 2007 being lead-free ones, Vardaman said.

Die attach materials developments are primarily focusing on materials technology for reducing package warpage and providing better compatibility with low-k dielectrics and lead-free processing. “We’re also seeing growth in film die attach, with increased growth in stacked die packaging,” Tracy said.

As far as WLP goes, the transition that was predicted a couple of years ago for some of the memory products to WLP hasn’t occurred — although there’s some use of developing WLP for integrating dielectrics into larger-die applications.

Some key materials development opportunities for the industry include reduced cost structures for standard laminate products, thin-core substrate materials with suitable properties to reduce warpage effects and improve handling, alloy development to support the ongoing migration to smaller diameter gold bonding wire, die attach materials and processes compatible with ultrathin wafer technologies, resin materials that don’t degrade moisture sensitivity levels and are compatible with low-k dielectrics and lead-free processing, and underfill solutions for fine bump pitch and large die.