IBM's manufacturing technique known as a "low-k dielectric" meticulously shields millions of individual copper circuits on a chip, reducing electrical capacitive loading and "crosstalk" between wires that can hinder chip performance and waste power. The company is designing custom chips that meet the high-performance and low-power consumption demands of next-generation microprocessors and other logic chips.
Today, designers work to improve chips by adding more circuits and packing them closer together on a single piece of silicon. They must constantly battle against interconnect "parasitics" (resistance, capacitance, and crosstalk) that impact signal speeds, power consumption, and operational limits constrained by capacitively coupled noise called "crosstalk" — just as crosstalk can occur on telephone lines. IBM has made breakthrough changes in interconnect materials to stave off these limits, first by migrating from aluminum to copper conductors in 1998, and now by changing the insulator around the conductors from fluorosilicate glass to organosilicate glass ("SiCOH"), a patented process that IBM and others have pioneered. Each change in materials has reduced interconnect parasitics by 20-40%. IBM leads the industry in the performance and reliability of these implementations, in this case with the strongest and most robust SiCOH material for the lowest resulting interconnect capacitance.
While IBM's techniques are proprietary, the low-k material is deposited in the same tools used for standard silicate and fluorosilicate glasses in prior (but concurrently produced) chip generations. The integration process is also similar, so making this change is very incremental to the manufacturing line. All yield and reliability parameters are the same for chips with conventional vs. low-k glasses. Achieving the same reliability for copper with low-k insulator, which is weaker than conventional insulators, remains a major differentiator and strength of IBM's chip technology relative to those of other chip manufacturers.
To speed the introduction of products based on this manufacturing process, IBM has a custom chip offering called Cu-08. This application specific integrated circuit (ASIC) template will be manufactured with IBM's 90-nanometer process technology, resulting in chip features as small as 0.08 microns (more than 1300 times thinner than a human hair). Cu-08 supports designs up to an unprecedented 72 million "gates," or circuits. IBM is the world's largest ASIC producer and widely recognized as the leader in innovative semiconductor manufacturing technologies.
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