Flip-Chip Packaging Becomes Competitive

Sally Cole Johnson, Contributing Editor -- Semiconductor International, 5/1/2009

Looking back 15 years ago, nearly everything was wire bonded. Today, flip-chip packaging is taking over. The basic flip-chip concept is to take a chip, place conductive bumps on the connection points, flip it over, put it face down and directly attach it to the circuit. Flip-chips eliminate excess packaging, while providing highly desirable benefits such as miniaturization, high-frequency operation, low parasitics and a high I/O density.

Flip-chips can be found in nearly every hot consumer gadget from cell phones and pagers to MP3 players and digital cameras. In the server space, virtually all logic modules are flip-chip packaged. And most ASICs, gaming, graphics processors, chipsets, field-programmable gate arrays (FPGAs) and digital signal processors (DSPs) are now also flip-chip modules.

The cost of gold bonding wire has been on the rise the past few years — making flip-chip even more appealing. "If we look at the cost two to three years ago, flip-chip was inherently more expensive," said Raj Pendse, vice president of flip-chip and emerging products at STATS ChipPAC (Singapore). "Flip-chip substrates typically cost two to three times the amount of a wire bond substrate, but the rising gold costs have evened out the differential in package costs. The flip-chip is becoming more cost-effective over a broader range of applications. In the past, it was used in the 1000 pin count range. It's becoming cost-effective in the 200–700 pin count range.".