Chemical etching method using a metal catalyst

An etching method comprising:

• forming nickel on a silicon substrate with a thickness of 10 nm to 30 nm,
• heat treating the silicon substrate, on which the nickel is formed, at a temperature of 300 to 600° C. to form a metal catalyst containing nickel silicide with a thickness of 20 nm to 70 nm, and
• selectively etching the silicon substrate in contact with the metal catalyst by reacting the silicon substrate, on which the metal catalyst is formed, with an etching solution containing H2O2 and HF.

The etching method of 13 further comprises,

• forming platinum with a first thickness on the silicon substrate before forming nickel on the silicon substrate,
• wherein forming nickel on the silicon substrate comprises forming nickel with a second thickness on the platinum,
• wherein the first thickness is ⅙ to 1/7 of the second thickness.

The etching method of 13 comprises,

• removing the metal catalyst remaining on the silicon substrate after etching the silicon substrate.

An etching method comprising:

• forming a metal catalyst containing nickel on a silicon substrate, wherein a thickness of the nickel is 3 nm or less, and
• selectively etching the silicon substrate in contact with the metal catalyst through chemical etching of the metal catalyst.

The etching method of 16, wherein the nickel has a thickness of 1 nm to 2 nm.