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US 8,298,437 B2Granted
Alkali etching liquid for silicon wafer and etching method using same
AssigneeSumco Corporation
InventorsTakahisa Nakashima, Makoto Takemura, Yasuyuki Hashimoto
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Abstract
An alkali etching liquid for a silicon wafer that includes an aqueous solution of potassium hydroxide, and from 0.1 g/L to 0.5 g/L of diethylene triamine pentaacetic acid. Furthermore, the Fe concentration of the aqueous solution of potassium hydroxide is no more than 50 ppb. An etching method that including a step of etching a silicon wafer with a resistivity of no more than 1 Ω·cm using the etching liquid.
Claims2
An alkali etching liquid for a silicon wafer, comprising:
- an aqueous solution of potassium hydroxide;
- and
- diethylene triamine pentaacetic acid at a content of 0.1 g/L,
- wherein a Fe concentration within said aqueous solution of potassium hydroxide is within a range from 20 to 50 ppb, and
- a Ni concentration within said aqueous solution of potassium hydroxide is 10 ppb.
2 more elements
Dependencies are inferred from the claim text.