Disposition Guidelines for STM WLCSP Wafer Sort
DISPOSITION GUIDELINES FOR STM WLCSP WAFER SORT
Disposition Guidelines for STM WLCSP Wafer Sort
--Follow Email Distribution to report the hold lots.MEMORY
DEVICESDevices Involved:Pxxx P71C_xxx P791_xxx FOR P7(V_4W080TA,
RESORT/RESORT AS FRESH IS FORBIDDEN (die will if resort)-Will
indicate in PDMS.Device Background: These are low cost serial
EPROM
One-Time Programming (OTP) device
T2 sort option used
Sorted on J750 platform
Internal Disposition:
Normally dont resort for function fail rejects bins, if see site
issue, dispose 1x wafer to resort and monitor first: Can recover,
resort the rest If no recovery report to STM disposition ( TAKE
NOTE it may change to other function bins(bin 5/8/9) due to the
program setting) FOR P7(V_4W080TA, RESORT IS FORBIDDEN (die will if
resort); If any wafer fails hi conty, it is ok to send that wafer
for resort (conty (HBIN4) only) without the need to ask STM for
disposition. If not recoverable, report to STM ; If for some
reason, prober hangs halfway while sorting the wafer, it is ok to
resort that affected wafer as fresh EXCEPT P7(V_4W080TA You may
trackout the wafers if the effective yield is >=98% but conty is
>0.5%. Please ensure that the conty is not caused by map shift.
If such pattern is detected, call PE. Illustration shown below:
Low Yield Lot Reporting: A table showing the following fields
for the low yield wafers:
Wafer ID -> wafer no. can be just wafer slot id
Total -> GDPW per wafer
Tested = GDPW-HBINF
Pass -> Pass dies per wafer
Fail -> Failed dies per wafer
O/S -> HBIN4 rejects
Effective Yield = (Pass / Tested) x100%
O/S % = (O/S / Tested) x 100%
Remarks -> can leave it blank.
Need to attach wafermaps and test summaries for the affected low
yield wafers in the email to STM.
Effective yield for STM WLCSP devices:- Pxx series devices ->
98% min yield, 0.5% max conty
Equation for calculating effective yield -> (BIN1 / (GDPW -
BINF)).
Equation for calculating effective conty yield -> (BIN4 /
(GDPW - BINF)).
It is ok to trackout the wafers if effective yield>=98% but
conty >= 0.5%
NORMAL DEVICESDevices Involved: Hxx H*CR_414* H*CR_427*
H*GD_432*
H*N6_411* ..Device Background:
T2 sort option used
Auto resort upon completion of wafer sorting
Sorted on HP93K C200 platform
Internal Disposition:
Send affected low yield wafers for 1X resort(on diff tester if
available). If still not able to recover, report to STM ~Thank
you~
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