WLCSP Rules¶
Allowed pitch |
Supported flows |
Allowed pitch |
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|---|---|---|---|---|---|
400 um |
500 um |
s8p-5rns8p-10r*ns8pf-10r*ns8pfn-20r*ns8p12-10r*ns8spf-10r* |
400 um |
500 um |
|
(pi1.-.-) |
(pi1_500.-.-) |
1st polyimide layer for WLCSP |
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Function: Opens over the pad openings; Allows RDL layer to connect to top metal |
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1 |
1 |
Min width of pi1 (for parallel opposite edges) |
35.00 |
35.00 |
|
2 |
2 |
Min spacing between pi1 |
20.00 |
20.00 |
|
3 |
3 |
pi1 must be enclosed by pad by atleast |
7.50 |
7.50 |
|
(rdl.-) |
(rdl_500.-) |
Re-distribution layer |
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Function: Re-distribution layer connects the top metal from the customer to the bumps |
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1 |
1 |
Min width of rdl (for parallel opposite edges) |
10.00 |
10.00 |
|
2 |
2 |
min spacing between two rdl |
10.00 |
10.00 |
|
3 |
3 |
pi1 must be enclosed by rdl by atleast |
10.00 |
10.00 |
|
(pi2.-.-) |
(pi2_500.-.-) |
2nd polyimide layer for WLCSP |
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Function: 2nd polyimide layer acts as a via between RDL and UBM |
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1 |
1 |
Min width of pi2 (for parallel opposite edges) |
170.00 |
220.00 |
|
3 |
3 |
Min spacing, no overlap, between pi1 and pi2 |
25.00 |
25.00 |
|
(ubm.-.-) |
(ubm_500.-.-) |
Under bump metal |
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Function: Layer added underneath the bump balls |
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1 |
1 |
Min width of ubm (for parallel opposite edges) |
215.00 |
250.00 |
|
3 |
3 |
pi2 must be enclosed by ubm by atleast |
15.00 |
15.00 |
|
4 |
4 |
ubm must be enclosed by rdl by atleast |
10.00 |
10.00 |
|
5 |
5 |
Min spacing, no overlap, between pi1 and ubm |
10.00 |
10.00 |
|
6 |
6 |
Min spacing between center of ubm and outer edge of the seal ring |
155.00 |
195.00 |
|
(bump.-.-) |
(bump_500.-.-) |
Bump balls for WLCSP |
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Function: WLCSP bump balls |
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1 |
1 |
Min width of bump (for parallel opposite edges) |
261.00 |
310.00 |
|
2 |
2 |
Min/Max pitch spacing between bump (center to center) |
400.00 |
500.00 |
|
2a |
2a |
Min/Max pitch spacing between bump (center to center) across the scribe |
NC |
400.00 |
500.00 |
3 |
3 |
Min spacing between bump and outer edge of the seal ring |
25.00 |
25.00 |
|
4 |
4 |
Min size of Chip_extent overlapping bump.dg |
750 X 1000 |
1000 X 1000 |
|
5 |
5 |
Max size of Chip_extent overlapping bump.dg |
6800 X 6800 |
6800 X 6800 |
(cpbo.-.-) |
1st polyimide (mask) |
||
|---|---|---|---|
Function: Opens over the pad openings; Allows RDL layer to connect to top metal |
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wlcsp.1 |
Min cpbo diameter over bond pad passivation opening |
20.00 |
|
wlcsp.2 |
Min bond pad passivation opening to create cpbo |
35.00 |
|
wlcsp.3 |
Min enclosure of cpbo over bond pad by pad:dg |
7.50 |
|
(rdl.-) |
Re-distribution |
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Function: Re-distribution layer connects the top metal from the customer to the bumps |
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x.1 |
Polymer 1 via and RDL1 capture pad should be designed as large as possible. The shape can be a circle, octagon, oblong, or a square with rounded corners. The via is not required to be centered within the passivation opening. Any offset is acceptable as long as the minimum overlap design rules are met |
exempt x.3a |
|
x.2 |
Fillet or “teardrop” is required between the trace and the RDL1 UBM capture pad to reduce stress and avoid 90°or acute angles which can cause over etching. If room permits, the fillet width shall be 90% of the RDL 1 UBM capture pad diameter and set back from pad shall be the same as the trace width. |
add teardrop |
|
x.3 |
Trace width and spacing shall be made equal and maximized where possible for optimized manufacturability, reliability and improved electrical performance (minimum width and spacing shall be limited to a localized area). |
Best practice |
|
wlcsp.1 |
Min rdl pad diameter over bond pad |
40.00 |
|
wlcsp.2 |
Min spacing between rdl and rdl larger than 30 um by 30 um and a run length > 60um |
15.00 |
|
wlcsp.3 |
cpbo (with max width of 30x30 must be enclosed by rdl by at least |
10.00 |
|
(cpmm2.-.-) |
2nd polyimide |
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Function: 2nd polyimide layer acts as a via between RDL and UBM |
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x.1 |
Capture pads are identified by (rdl and bump) enclosing pmm2 |
||
wlcsp.1 |
Min spacing, no overlap, between cpbo and cpi2 on different nets |
25.00 |
|
wlcsp.2 |
Min enclosure of cpbo by cpmm2 (no straddle) |
15.00 |
|
wlcsp.3 |
Min cpmm2 pad diameter |
155.00 |
|
wlcsp.4 |
Min diameter of rdl capture pad under cpmm2 |
235.00 |
|
wlcsp.5 |
Min enclosure of rdl by cpmm2 |
15.00 |
|
wlcsp.6 |
Minimum remaining fraction (polymer 2) size of full via sizenAdd a radius or chamfer on sharp corners of truncated 2nd polyimide via and corresponding RDL capture pad. |
0.5 |
|
(ubm.-.-) |
Under bump metal |
||
Function: Layer added underneath the bump balls |
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1 |
Min width of ubm (for parallel opposite edges) |
215.00 |
|
2 |
pmm2 must be enclosed by ubm by atleast |
15.00 |
|
3 |
Min spacing between center of ubm and outer edge of the seal ring |
250.00 |
|
(bump.-.-) |
Bump balls for WLCSP |
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Function: WLCSP bump balls |
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1 |
Min width of bump (for parallel opposite edges) |
264.00 |
|
2 |
Min/Max pitch spacing between bump (center to center w/2x snapGrid tolerance) |
400.00 |