US 12,442,993 B2
System and method for measuring alignment
Chia-Te Chou, Brea, CA (US); Albert Benzoni, South Pasadena, CA (US); Michael Lee, Los Angeles, CA (US); Cristian Stagarescu, Los Angeles, CA (US); William Vis, Pasadena, CA (US); and Melissa Ziebell, Pasadena, CA (US)
Assigned to Rockley Photonics Limited, Altrincham (GB)
Appl. No. 18/257,231
Filed by ROCKLEY PHOTONICS LIMITED, Cheshire (GB)
PCT Filed Dec. 17, 2021, PCT No. PCT/EP2021/086567
§ 371(c)(1), (2) Date Jun. 13, 2023,
PCT Pub. No. WO2022/129563, PCT Pub. Date Jun. 23, 2022.
Claims priority of provisional application 63/127,955, filed on Dec. 18, 2020.
Prior Publication US 2024/0094484 A1, Mar. 21, 2024
Int. Cl. G02B 6/42 (2006.01); H01L 23/544 (2006.01)
CPC G02B 6/4224 (2013.01) [H01L 23/544 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method, comprising:
measuring a first offset, the first offset being an offset along a first direction between a first alignment mark and a second alignment mark,
the first alignment mark being an alignment mark on a first edge of a source die,
the second alignment mark being an alignment mark on a target wafer, the first direction being substantially parallel to the first edge of the source die, and
measuring a second offset, the second offset being an offset along a second direction between a third alignment mark and a fourth alignment mark,
wherein:
the third alignment mark is an alignment mark on a second edge of the source die,
the fourth alignment mark is an alignment mark on the target wafer,
the second edge of the source die is substantially perpendicular to the first edge of the source die,
the second direction is substantially parallel to the second edge of the source die,
the second direction is substantially parallel to the target wafer,
the fourth alignment mark is a first pillar on the target wafer, and
the method further comprises measuring a third offset, along a third direction, between a top surface of the first pillar and an alignment feature of the source die.