Pentium 4 yields ‘not impressive’
30 per cent failure rate reported
Someone at Intel's notoriously-leaky Qiryat-Gat plant (Fab 18) in Israel has been blabbing to Israeli paper Haaretz about teething troubles with the upcoming Pentium 4 chip.
Haaretz reports that there are only two steppers in the world capable of handling one critical part of the P4 manufacturing process. Both of them are at Qiryat-Gat and one of them doesn't work properly.
The paper claims that P4 was meant to be built using new machines which weren't delivered on time and the old steppers aren't really up to the task with yields of 70 per cent on the P4 compared with 80 per cent for Pentium III parts.
And due to P4's larger die size, only 100 chips per wafer can be built, compared with 250 PIIIs. As a result, P4 production is running at just 70,000 a week, Intel reportedly having set a target of 100,000 a week before the part can be launched.
Intel was unavailable for comment at press time. ®
A stepper is a lithography tool, which takes a resist coated wafer, and shoots a high intensity light through a mask, imprinting the pattern of lines into the photoresist, which acts like photographic film.
The wafers are then developed, removing all resist except that located on top of the lines. Then the wafers are sent to dry etch, where an etcher, using RF-energized gases, etches away any exposed material, leaving the lines that were coated by resist.
The wafers are then sent to 'ash', where the resist is removed from the lines, leaving the finished layer.
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