FormFactor's new MEMS probing contact technology

LIVERMORE, USA: FormFactor Inc. has introduced a new MEMS probing contact technology for its advanced probe cards for wire bond logic and system-on-chip (SoC) wafer testing.

The new TrueScale Multi-Tier contact technology will support fully populated, staggered pad layouts down to 25/50 microns in size, which are utilized in leading-edge wire bond logic and SoC chip designs at 45-nm and below nodes.

By enabling reliable and accurate probing of these staggered pad layouts, FormFactor is well-positioned to bring the enhanced capabilities of its MEMS contact technology to the vast majority of wire bond logic and SoC wafer test applications. These applications include wireless baseband and digital media, such as mobile phones and MP3 players, as well as portable gaming devices.

"Mobile communications and consumer processors are driving more functionality into smaller and smaller form factors -- creating a critical need for new test solutions that can support tight-pitch, staggered pad layouts," stated Bruce Bolliger, vice president and general manager, SOC Business Unit, at FormFactor.

"Our new proprietary probe contact technology brings MEMS contact reliability and electrical performance to the leading-edge SoC test market. In addition, FormFactor has a roadmap to extend our new contact technology to even smaller and more complex pad layouts -- supporting aggressive SoC test roadmaps."

As the functionality and complexity of wire bond logic and SoC devices continue to rise, the number of I/Os per device increases. With semiconductor dimensions shrinking, more of these I/Os are being packed into a smaller area. This higher pad density is driving the transition from single-row to staggered pad layouts for most of today's advanced wire bond logic and SoC designs.

Traditional vertical probe solutions that support staggered pad layouts have difficulty scaling to the smaller dimensions required for advanced SoC devices, while cantilever probe solutions require frequent cleaning and maintenance to ensure proper alignment with the pads, which limits test cell uptime and efficiency.

In addition, vertical and cantilever probes require greater contact force for stable contact, which increases the likelihood of damaging the bond pad and circuit underneath -- resulting in yield loss. FormFactor's new probe contact technology leverages the company's leading expertise in MEMS to provide improved probe performance and productivity for the most advanced wire bond logic and SoC test applications.

Higher Performance and Productivity over Conventional Probing Technologies
Based on FormFactor's MicroSpring MEMS contact technology, the new probe contacts are highly scalable, enabling 25/50-micron pitch staggered pad probing. This provides the ability to probe higher pad densities with reliable x/y positioning, which enables IC manufacturers to increase the pad count per die and support continued die shrinks.

In addition, the scalable contacts enable the production of higher pin-count probe cards that can support x2 through x16 full logic sort testing and even higher levels of test parallelism (x64, x128, x256) for embedded memory test applications -- allowing IC manufacturers to increase their test throughput with their existing capital equipment.

The new probe contacts are designed to scrub with optimized electrical contact -- providing better test results and reducing false test failures, which can improve yields. At the same time, the low force associated with the MicroSpring design of the new probe contacts enables circuit-under-pad (CUP) testing with no damage to the dielectric layer under the probe pad.

FormFactor's new probe contacts also require minimal maintenance with no spring positioning adjustment. In addition, the new probe contacts are designed to support millions of touchdowns -- providing significantly greater probe card lifetime and test cell uptime versus cantilever and vertical probe cards.

The new TrueScale Multi-Tier contact technology is now available on FormFactor's complete line of TrueScale probe cards.