Chip-Scale Packaging Approach Cuts Losses

May 13, 2008
This innovative, semiconductor-based chip-scale-packaging technology promises extreme miniaturization while minimizing signal losses for a wide range of RF/microwave components.

Chip-scale packaging (CSP) offers great promise for shrinking the size and cost of certain semiconductor devices. With customer pressures to reduce the size, weight, and cost of commercial semiconductors for wireless handsets, infrastructure equipment, and other commercial electronic applications, semiconductor manufacturers have sought ways to reduce the impact of packaging on their chips. Avago Technologies (www.avagotech. com) may have found a better way, with the industry's first semiconductor-based CSP technology, which they have named WaferCap CSP technology.

The basic idea of a CSP is to house a single chip within a package having an area no more than 1.2 times the size of the die itself. In some current definitions, a CSP refers to a package having 0.8-mm or smaller pitch. CSP technology offers several advantages over conventional surface-mount-technology (SMT) packaging, including smaller size, lighter weight, easier assembly process, lower production costs, and the potential for higher electrical performance. CSP solutions are currently available in a variety of different versions, including those that are flip-chip mounted, those in a ball-grid-array (BGA) configuration, and those that require wire bonds.

Avago Technologies has advanced upon earlier CSP efforts and has developed a CSP solution capable of extremely low loss at microwave and millimeter-wave frequencies. In fact, the WaferCap technology is projected to serve applications through 100 GHz. WaferCap devices, which can eliminate the need for wire bonding even at high frequencies, can be processed using standard SMT assembly techniques. The WaferCap approach provides a low-loss signal path through the package/ chip with significantly reduced parasitic circuit elements compared to conventional SMT packages.

The company has introduced a line of high-performance, broadband RF/ microwave amplifiers that demonstrate some of the capabilities of the new WaferCap CSP technology. Avago's new VMMK-2x03 series of broadband amplifiers (see table) are supplied in a 0402 size package measuring just 1.00 x 0.50 x 0.25 mm. The product family includes models operating from 500 MHz through 12 GHz. Fully matched for 50-Ohm systems, these miniature RF/ microwave amplifiers are suitable for commercial and military applications. In addition, the new WaferCap CSP technology offers the potential to shrink a wide range of RF/microwave components, including attenuators, detectors, mixers, and switches. Avago Technologies, 350 W. Trimble Road, Building 90, San Jose, CA 95131; (408) 435-7400, (877) 673-9442, Internet: