US 12,327,766 B2
Laser processing method, semiconductor device manufacturing method, and examination device
Takeshi Sakamoto, Hamamatsu (JP); Yasutaka Suzuki, Hamamatsu (JP); and Iku Sano, Hamamatsu (JP)
Assigned to HAMAMATSU PHOTONICS K.K., Hamamatsu (JP)
Appl. No. 17/281,505
Filed by HAMAMATSU PHOTONICS K.K., Hamamatsu (JP)
PCT Filed Oct. 2, 2019, PCT No. PCT/JP2019/039002
§ 371(c)(1), (2) Date Mar. 30, 2021,
PCT Pub. No. WO2020/071455, PCT Pub. Date Apr. 9, 2020.
Claims priority of application No. 2018-189309 (JP), filed on Oct. 4, 2018.
Prior Publication US 2021/0398855 A1, Dec. 23, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 21/78 (2006.01); B23K 26/00 (2014.01); B23K 26/03 (2006.01); B23K 26/53 (2014.01); H01L 21/66 (2006.01); B23K 103/00 (2006.01); B24B 7/22 (2006.01); B24B 49/12 (2006.01)
CPC H01L 21/78 (2013.01) [B23K 26/0006 (2013.01); B23K 26/0093 (2013.01); B23K 26/032 (2013.01); B23K 26/53 (2015.10); H01L 22/12 (2013.01); B23K 2103/56 (2018.08); B24B 7/228 (2013.01); B24B 49/12 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A laser processing method comprising:
a first step of preparing a wafer including a semiconductor substrate having a front surface and a back surface and a functional element layer formed on the front surface, and forming a plurality of rows of modified regions in the semiconductor substrate along each of a plurality of lines by irradiating the wafer with laser light from the back surface side along each of the plurality of lines;
a second step of inspecting a tip position of a fracture in an inspection region with inspection light, the tip position of the fracture being in the thickness direction of the semiconductor substrate, the tip position being within the semiconductor substrate between the back surface and the modified region closest to the back surface among the plurality of rows of modified regions, the fracture extending to the back surface side from the modified region closest to the back surface, in the second step, by passing the inspection light through an objective lens having a numerical aperture of 0.45 or more, to inspect the tip position of the fracture having a width smaller than a wavelength of the inspection light; and
a step of notifying an operator of a result of the inspecting the tip position, wherein
in the first step, the wafer is irradiated with the laser light from the back surface side along each of the plurality of lines under a condition that a fracture extending through the plurality of rows of modified regions is formed, and
in the second step, the tip position is inspected by aligning a focus of the objective lens from the back surface side in the inspection region and detecting, through the objective lens, the inspection light propagating in the semiconductor substrate from the front surface side to the back surface side.