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 SEH Polished Wafers for Prime Device Manufacture
Low Defect Crystals
Vacancy related crystal defects such as COP/FPD (Crystal Originated Pits/Flow
Pattern Defects) can cause near surface problems during device manufacture.
Examples of the device problems are poor GOI and current leakage
in P-N Junctions. COPs are 0.1-0.2um octahedral shaped voids with walls covered
by oxide. FPD is a vacancy cluster related defect exposed by preferential etching.
Adding an epitaxial layer can eliminate these defects, although epi growth
adds costs. For some device applications, a low defect crystal growth method
can be applied to reduce the number of vacancy defects in the near surface
device region. Modification of the crystal pulling speed and the cooling rate
of the crystal can result in lower vacancy defect levels. This allows for the
recombination between vacancies and interstitials, vacancy agglomeration and
oxygen control resulting in reduction of surface defects.
SEH is able to provide two different levels of surface defect reduction: Low Defect Crystal and Near Perfect, COP Free Crystal. Both of these products provide
a significant reduction in surface defects when compared to the standard CZ
crystal. SEH produces near Epi surface quality in a FPD/COP free Polished Wafer
with our NPC wafer.
SEH CZ Crystals can provide the following quality levels:
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| FPD |
500-600/cm2 |
<300/cm2 |
0/cm2 |
| COP |
>0.10µm of
< 1200 / wafer |
>0.10µm of
< 500 / wafer |
>0.10µm of
< 20 / wafer |
| COP |
>0.12µm of
< 400-500 / wafer |
>0.12µm of
< 200 / wafer |
>0.12µm of
< 10 / wafer |
| GOI |
45-50% good die |
60-70% good die |
>90% good die |
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