Nepcon West Roundup
A variety of developments were displayed at Nepcon West
John Baliga, Associate Editor -- Semiconductor International, 5/1/1998
Nepcon West Roundup
Flip Chip Technologies (FCT, Phoenix, Ariz.) introduced its Ultra CSP packaging technology at Nepcon West in March. The wafer level packaging technology is said to have half the cost per I/O of current CSP options and a price competitive with TSOPs or QFPs. The package is actually a flip-chip, with a benzocyclobutene (BCB) redistribution layer, that has bumps placed in JEDEC standard CSP area array patterns. The BCB serves as the packaging. Tests were still in progress at press time, but yields are projected to be more than 98%.
Express Packaging Systems (Palo Alto, Calif.) presented its NuCSP land grid array (LGA) package at the technical conferences. A die is flip-chip attached onto a substrate made of FR-4 or bismaleimide triazine (BT) that has both electrical and thermal vias.
Amkor Technology (Chandler, Ariz.) introduced its new 'near chip scale' ball-grid array (BGA) series of packages called fleXBGA. It has a die-up wirebonded configuration using flexible circuit tape as the substrate. Interconnect pitch spacings are 1.0 mm and 0.8 mm, and its mounted height is 1.0 mm.
Two companies demonstrated vacuum encapsulation equipment, primarily for use with Tessera's (San Jose, Calif.) µBGA package. Camelot Systems (Haverhill, Mass.) demonstrated its CAM/ALOT 3900, and Asymtek (Carlsbad, Calif.) demonstrated its C-718-VE. Both systems provide pre-dispense, dispense and post-dispense vacuum chambers, though Asymtek considers the pre- and post-chambers to be options. Using this method, any voids would contain a vacuum, and they close when brought up to ambient pressure.
Lambda Technologies (Morrisville, N.C.) introduced its variable frequency microwave (VFM) curing systems for adhesives and encapsulants. They use a programmable set of microwave frequencies between 5.85 and 7.0 GHz to perform the curing. The change in frequencies avoids arcing by keeping charge from collecting on metal traces. Curing is done quickly, typically in a few minutes as opposed to 30 min to 2 hours for forced air ovens. On laminate substrates, only the chip and the polymer to be cured absorb the energy, reducing CTE mismatch problems associated with cooldown.
AlliedSignal Electronic Materials (Los Gatos, Calif.) announced its plans to produce film-based substrates for flip-chip and multichip modules. Its new technologies are intended to eliminate conventional drilling, reduce layer counts, achieve 25 µm linewidths and spacings and furnish buried and blind vias at little or no added cost.
Flip-Chip BGA
Fujitsu's FCBGA package is designed for high I/O, high-frequency applications.
Engineers at Fujitsu Microelectronics (San Jose, Calif.) presented their advanced packaging solution, flip-chip BGA (FCBGA), in February at the Pan Pacific Microelectronics Symposium in Kona, Hawaii. The package is intended for use with high-frequency, high I/O devices such as high-end RISC processors, IP and ATM switching elements and system-on-a-chip applications.
The primary purpose of the package is not to save space, nor is it a chip scale or near chip scale package. It takes the space necessary to handle thermal considerations (see figure). Flip-chip attach is used because the number of I/Os alone is expected to make peripheral wirebonding impractical and because of electrical considerations. It has a laminate build-up substrate with 50 µm lines and spaces. Work on 25 µm lines and spaces is in progress.
Polymer Flip Chip (Billerica, Mass.) opened its assembly production lines. The facility performs solderless flip-chip assembly and has the capacity for 10 million units/year. The company also licensed its process to a European manufacturer of contactless smart cards.
Karl Suss (Waterbury Center, Vt.) and Motorola's Semiconductor Products Sector (Austin, Texas) agreed to jointly develop an aligned bonding technology for Motorola's MEMS accelerometers.
Kulicke & Soffa Industries (Willow Grove, Pa.) and Amkor/Anam Philipinas Inc . announced a plan to implement a fully automated semiconductor assembly line, from wafer preparation to mold, at Amkor's P3 factory in Manila. The PBGA pilot line is scheduled to be operational in the fourth quarter of 1998. It will use PRI Automation's (Billerica, Mass.) AeroTrak overhead monorail network along with new and existing equipment.
Sunlight Systems Ltd. changed its name to Nanopierce Technologies (Denver, Colo.) after acquiring Particle Interconnect's (Denver, Colo.) particle interconnect technology. Nanopierce will use the technology to develop diamond particle-coated substrates for integrated circuit packaging and interconnection.
SGS-Thomson Microelectronics (Saint Genis, France), Siemens AG (Munich, Germany) and Advanced Semiconductor Engineering Inc. (ASE, Kaohsung, Taiwan) licensed Tessera's (San Jose, Calif.) µBGA packaging technology.
Kyocera America (San Diego, Calif.) will be adding an automated flip-chip assembly line to its San Diego facilities at an estimated cost of $5.7 million. The 5000 ft2 line will initially be set up for ceramic packages, with plans to add laminate capabilities as demand dictates.
