US 12,170,225 B2
Laser processing method
Yuji Hadano, Tokyo (JP); and Keiji Nomaru, Tokyo (JP)
Assigned to DISCO CORPORATION, Tokyo (JP)
Filed by DISCO CORPORATION, Tokyo (JP)
Filed on Sep. 22, 2021, as Appl. No. 17/448,425.
Claims priority of application No. 2020-174049 (JP), filed on Oct. 15, 2020.
Prior Publication US 2022/0122886 A1, Apr. 21, 2022
Int. Cl. H01L 21/268 (2006.01); H01L 21/56 (2006.01); H01L 21/78 (2006.01)
CPC H01L 21/78 (2013.01) [H01L 21/268 (2013.01); H01L 21/56 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A laser processing method comprising:
a scattered-light blocking film stacking step of stacking a scattered-light blocking film that blocks scattered light of a laser beam on an upper surface side of a wafer, wherein the scattered-light blocking film is stacked by coating with a liquid resin in which powder of carbon, Si, or a metal is mixed, and wherein a thickness of the scattered-light blocking film is between 0.1 to 0.5 μm;
a holding step of holding a lower surface side of the wafer by a chuck table;
a laser processing step of forming a layer of water on the upper surface side of the wafer and irradiating a region to be processed in the wafer with the laser beam while moving the chuck table and a laser beam irradiation unit relatively, wherein the laser beam is transmitted through a transparent member of a laser beam irradiation unit which is flush with an ejection port which supplies the water; and
a scattered-light blocking film removal step of removing the scattered-light blocking film from the wafer for which the laser processing step has ended.