Substrate processing method and substrate processing device

A substrate processing method to process a substrate including an etching target that represents at least one of silicon single crystal and polysilicon, the substrate processing method comprising:

• etching the etching target by supplying the substrate with alkaline first etching liquid;
• and
• etching the etching target by supplying the substrate with alkaline second etching liquid before or after the first etching liquid is supplied to the substrate, the second etching liquid containing a chemical compound that inhibits contact of a hydroxide ion and the etching target, the second etching liquid having a smaller difference between a maximum value and a minimum value of etching speeds for a (110) plane, a (100) plane, and a (111) plane of silicon than that of the first etching liquid, the second etching liquid having the maximum value of the etching speeds smaller than that of the first etching liquid, wherein
• the first etching liquid is alkaline etching liquid containing the chemical compound and
• the first etching liquid and the second etching liquid differ from each other in at least one of composition, concentration, and temperature.

A substrate processing method to process a substrate including an etching target that represents at least one of silicon single crystal and polysilicon, the substrate processing method comprising:

• etching the etching target by supplying the substrate with alkaline first etching liquid;
• and
• etching the etching target by supplying the substrate with alkaline second etching liquid before or after the first etching liquid is supplied to the substrate, the second etching liquid containing a chemical compound that inhibits contact of a hydroxide ion and the etching target, the second etching liquid having a smaller difference between a maximum value and a minimum value of etching speeds for a (110) plane, a (100) plane, and a (111) plane of silicon than that of the first etching liquid, the second etching liquid having the maximum value of the etching speeds smaller than that of the first etching liquid;
• wherein
• one cycle including the etching with the first etching liquid and the etching with the second etching liquid is performed a plurality of times.