For ESD test (HBM) x* R4 g' J+ @9 O3 z8 U
The following are the test combination: ( Q/ ^" r; K" j1. Power to Power! I7 D, i) g ~$ ^4 @
2. Power to Ground- _+ W6 V+ L% L% J3 v
3. IO to Power! l7 a: L6 S: B3 {
4. Io to Ground" C( D$ K: y( y! r) f! J
5. IO to IO1 i+ p! B5 k7 N0 S9 {: M; W
(different power domain need to be treated as different power. For ground usually you can treat as one group_silicon use substrate as common ground. But if you measure two different ground pin/ball > 2ohms. It should be seperated as 2 grond.)" w d( C1 }/ c$ H0 F1 u! B
: e- X7 G- D) Xthe total zap time fomula will be~ 2(+/- polarity) X (IO#X(P#+G#)+IO#+P#X(P#-1)X(P#-2)X...X1+P#XG) 7 [) C8 m! t( i" vFor example: You have IO1/IO2/IO3/P1/P2/G1# _+ C! r9 t6 }; W3 H4 e
2x((3X(2+1)+3+2X1+2X1)=25(multiple the zap interval) $ l! b1 x* N% k" k+ ]So for high pin count it will take a lot of time. But it won't take more than a week(for one chip). ( @ m5 p' W B9 ~ * Y; V" x# n$ TFor your reference.
thanks wesleysungisme for your answer.* z6 Z+ M0 I$ @$ n& q' D
as our pin count is over 1000 and no. of power is ~ 20, so it's quite time-consuming. ! X+ J2 _- m8 \and there is technical issue about bonding all the dies into COB for ESD zapping, i wonder if anyone could share their practise? we feel difficult to strictly follow JEDEC standard.