Wafer manufacturing method, epitaxial wafer manufacturing method, and wafer and epitaxial wafer manufactured thereby
A wafer manufacturing method, an epitaxial wafer manufacturing method, and a wafer and epitaxial wafer manufactured thereby, are provided. The wafer manufacturing method enables the manufacture of a wafer with a low density of micropipe defects and minimum numbers of particles and scratches. The epitaxial wafer manufacturing method enables the manufacture of an epitaxial wafer that has low densities of defects such as downfall, triangular, and carrot defects, exhibits excellent device characteristics, and improves the yield of devices.
1. A wafer manufacturing method, the method comprising:
arranging a raw material and a silicon carbide seed crystal to face each other in a reactor having an internal space;
controlling a temperature, a pressure, and an atmosphere of the internal space to sublimate the raw material, and grow a silicon carbide ingot from the silicon carbide seed crystal;
cooling the reactor, and recovering the silicon carbide ingot;
cutting the recovered silicon carbide ingot into a wafer; and
planarizing the wafer, and polishing a first surface of the planarized wafer,
wherein a heat insulating material surrounds an outer surface of the reactor, a heating device is configured to control the temperature of the internal space, and a density of the heat insulating material is 0.14 g/cc to 0.28 g/cc,
wherein the planarizing of the wafer comprises performing a first processing operation with a first grinding wheel which has a surface particle size of 1000 mesh to 3000 mesh, and performing a second processing operation with a second grinding wheel which has a surface particle size of 6000 mesh to 10000 mesh,
wherein the planarizing of the wafer further comprises performing a chemical mechanical polishing operation, and
wherein after chemical mechanical polishing is performed on the wafer, a total length of scratches on a first surface of the wafer is less than a diameter of the wafer, an averaae density of particles has a size of 0.3 μm or more is 3/cm2 or less, and an average density of micropipes on the first surface is 3/cm2 or less.
2. The method of claim 1 , wherein a feed rate of the first grinding wheel to the wafer in the first processing operation is 0.2 μm/s to less than 1.5 μm/s.
3. The method of claim 1 , wherein a feed rate of the second grinding wheel to the wafer in the second processing operation is 0.2 μm/s to less than 1.5 μm/s.
4. The method of claim 1 , wherein a wafer manufacture index (Pi) value of the wafer is not greater than 30, based on the following Equation:
Pi−Di×Vi×Vii×100
where Di is the density of the heat insulating material (g/cc), Vi is the feed rate of the first grinding wheel (μm/s), and Vii is the feed rate of the second grinding wheel (μm/s).
5. The method of claim 1 , wherein the first grinding wheel is configured to rotate at a rate of 1000 rpm to 2000 rpm.
6. The method of claim 1 , wherein the second grinding wheel is configured to rotate at a rate of 600 rpm to 1800 rpm.