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Technology Stocks : General Lithography -- Ignore unavailable to you. Want to Upgrade?

To: Ian@SI who wrote (1080)	7/19/1998 6:46:00 PM
From: Andrew Vance	Read Replies (1) \| Respond to of 1305

DRAM fabs obsolete faster than Logic fabs historically. As a matter of fact, it was not uncommon for older DRAM fabs to be converted to Logic or ASIC devices. Recently it is looking like they have reached parity and the discrepancies may no longer exist. Check what is happening to some of the Asian Fabs as they are trying to convert DRAM Production to other types of IC manufacturing. The mask has to be aabused to be wear out. There is some sort of degradation of the mask/reticle materials after a certain extremely large amoiunts of exposure. Ambient environmental issues could cause some of the chrome to get "zapped". However, for the most part, the masks and reticles are obsoleted in favor of re-designs, shrinks, or completely new designs. I would like to give you the "it depends" answer and straddle the fence but I won't. The chip design runs its full product life cycle a vast majority of the time and dies off well before the reticle/mask tooling needs to be replaced. DRAM life cycles seem to be shorter than that of logic devices. More importantly, I believe the DESIRE to advance technology and to shrink feature sizes for improved performance cause the fabs and masks to be replaced before they are really ready for the scrap heap. This has got to change since the cost of a fab is not longer in the hundreds of millions but rather in the couple of billions. IF things do not change, companies may never get the appropriate paybacks for their new costly facilities. Especially when the margins in things like DRAM have dropped to practically nothing. Andrew Sorry for missing the question.

To: Ian@SI who wrote (1080)	7/20/1998 12:11:00 AM
From: Katherine Derbyshire	Read Replies (2) \| Respond to of 1305

The mask lifetime question has actually come up before, either here or in one of the mask house threads. This time, I have an answer. (From SVG's John Shamaly) DRAM houses get ~5-10,000 wafers/reticle logic houses get ~3-4,000 wafers/reticle ASIC houses get ~25 wafers/reticle. So this probably puts the physical lifetime of the mask at in the neighborhood of 10,000 wafers+. 30,000 wafer starts/month is a large fab. Non-optical lithography techniques may have different numbers. Mask lifetime is a particular concern with x-ray lithography. Katherine