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Technology Stocks : Semi Equipment Analysis

SOXX 291.39

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Nov 26 4:00 PM EST

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To: robert b furman who wrote (27990)	1/18/2006 11:00:08 AM
From: Kirk ©	Read Replies (2) of 95479

"Batch is dead." Not really dead... they just do it all on one wafer to be more efficient. -g- Lets see if we can make a case for where to invest future dollars. I started working at HP when we were converting a 2" line to a 3" line. It was a huge deal and getting bipolar models (for transistors, resistors etc.) for chips on 3" wafers was a huge project for a few engineers for many years in the late 1970's and early 1980's. Pies are squared so 2" wafers had 3.14 sq inches of silicon, much of it unusable due to edge effects. I believe a batch of wafers at that time was 12.. so a batch was 37.7 sq inches of usuable silicon. Today many process are single wafer. It allows easier rework and better process control. Also, getting even gas distribution to all parts of a wafer is much easier in single wafer mode. a 12" wafer has 3.14x6^2 sq inches of usable silicon with far less loss to edges. 3.14x36 vs 3.14x12 or 3 times as much silicon processed on a single wafer than in a "full batch" 25-30 years ago. So, compared to very long time ago... we are still in batch mode and processing more square inches at a time. -g- otherwise you are correct. 12 8" wafers in a batch are 12 x pi x 4^2 = 12 x pi x 16 1 12" wafer in a batch is 1 x pi x 6^2 = 1 x pi x 36 192pi vs. 36 pi or a factor of 5.33 that assumes a 12 wafer batch. Maybe they did more and perhaps less? The real metric is dollar cost per sq cm of processed silicon. If you can get better yield with single processing, then it really works in your favor to go to single wafer processing for more and more critical steps. I think this is why automated systems are the place many want to invest because it can make single wafer processing "look like" batch processing to your labor costs... same labor cost to load a wafer or a batch of wafers into a tool so if the tool can self load and unload one wafer at a time, it lowers labor costs. It looks like it is batch processing but getting single wafer quality.

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