WAFER EVALUATION METHOD, WAFER PRODUCTION METHOD AND DEVICE PRODUCTION METHOD
A wafer evaluation method according to the present embodiment includes installing a SiC wafer or a SiC epitaxial wafer on a porous plate having a plurality of through holes; installing a lid on a second surface opposite to a first surface of the SiC wafer or the SiC epitaxial wafer with an O-ring therebetween; supplying a gas into a space surrounded by the second surface, the O-ring and the lid and pressurizing the inside of the space; and measuring the pressure in the space after a certain period has elapsed and inspecting whether there is a threading defect in the SiC wafer or the SiC epitaxial wafer.
1 . A wafer evaluation method, comprising:
installing a SiC wafer or a SiC epitaxial wafer on a porous plate having a plurality of through holes;
installing a lid on a second surface opposite to a first surface of the SiC wafer or the SiC epitaxial wafer with an O-ring therebetween;
supplying a gas into a space surrounded by the second surface, the O-ring and the lid and pressurizing the inside of the space; and
measuring the pressure in the space after a certain period has elapsed and inspecting whether there is a threading defect in the SiC wafer or the SiC epitaxial wafer.
2 . The wafer evaluation method according to claim 1 ,
wherein the initial pressure in the space immediately after the gas is supplied is 0.2 MPa or more.
3 . The wafer evaluation method according to claim 1 ,
wherein the initial pressure in the space immediately after the gas is supplied is 0.3 MPa or less.
4 . The wafer evaluation method according to claim 1 ,
wherein, when the difference between the initial pressure in the space immediately after the gas is supplied and the holding pressure in the space after a certain period has elapsed is more than 1/100 of the initial pressure, it is determined that there is the threading defect.
5 . The wafer evaluation method according to claim 1 ,
wherein the O-ring has an inner diameter of 80 mm or less.
6 . The wafer evaluation method according to claim 1 ,
wherein the wafer is the SiC wafer.
7 . The wafer evaluation method according to claim 1 ,
wherein the wafer is the SiC epitaxial wafer.
8 . A wafer production method, comprising
an evaluation process using the wafer evaluation method according to claim 1 .
9 . The wafer production method according to claim 8 , further comprising
an image screening process for checking whether there is the threading defect,
wherein the image screening process is performed before the evaluation process.
10 . The wafer production method according to claim 9 ,
wherein the evaluation process includes a screening process for screening a wafer having the threading defect with an area of larger than 0 μm 2 and 182 μm 2 or less when it is determined that there is the threading defect in the image screening process.
11 . A device production method, comprising
an evaluation process using the wafer evaluation method according to claim 1 .
12 . The device production method according to claim 11 , further comprising
an image screening process for checking whether there is the threading defect,
wherein the image screening process is performed before the evaluation process.
13 . The device production method according to claim 12 , further comprising a device producing process,
wherein the evaluation process includes a screening process for screening a wafer having the threading defect with an area of larger than 0 μm 2 and 182 μm 2 or less in the evaluation process when it is determined that there is the threading defect in the image screening process, and
wherein, in the device producing process, a device is produced using a wafer having the threading defect with an area of larger than 0 μm 2 and 182 μm 2 or less.