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Technology Stocks : Intel Corporation (INTC) -- Ignore unavailable to you. Want to Upgrade?

To: Steve Porter who wrote (47106)	2/3/1998 11:25:00 PM
From: Paul Engel	Read Replies (1) \| Respond to of 186894

Steve - Re: " todays processors will be affected by Maxwell's equations." At the risk of sounding glib, today's processors aren't limited by Maxwell's equations. They are primarily limited by heat (Thermal) dissipation. This doesn't apply to all processors or all processes - some CPUs are limited by their architecture, design and layout. Where these limits do not apply - DEC's Alpha and Intel's Pentium II/Deschutes), for example - heat generation limits the ultimate speed the processor can run at. The use of active cooling devices, to keep the junction (i.e., bulk silicon) temperature at "reasonable" levels, will enable extremely high clock rates - well in excess of 500 MHz. DEC's new Alpha chip will run at 600 MHz and I wouldn't be surprised if Intel couldn't run their Deschutes at, say, 533 MHz. Re: "Isn't there some difficulty in using copper in terms of capacitance on tightly packed circuits that exist in the core of modern CPUs?" Long, narrow conductors give rise to larger RC time constants and densely packed conductors produce excessive parasitic (fringing) capacitance. The use of copper in place of aluminum alloys, which results in lower resistance (all other things being equal) will LOWER the RC time constant (smaller R) and reduce these parasitic capacitances. The difficulty with using copper is one of materials science. Copper readily diffuses through SiO2 (Silicon Dioxide or "glass") and can therefore diffuse/migrate to the bulk silicon where it absolutely will destroy circuit operation due to several things, not the least of which is killing the minority carrier lifetimes (electrons in n-channel devices). To prevent this, special barrier films have to be provided to completely surround the copper traces. These barrier films prevent/block the diffusion of copper. Needless to say, this adds increasing complexity - and risk - to the wafer fab process. Any copper contamination inside a wafer fab - such as in an oxidation or diffusion tube - can wipe out every wafer in a fab if cross-contamination spreads the copper from lot to lot, machine to machine. Paul