Methods to improve etch uniformity across a semiconductor substrate when etching with a hydrofluoric acid (HF) and nitric acid (HNO3) solution
AssigneeTokyo Electron Limited
InventorsDerek Bassett, Kate Abel
Life of this patent
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Abstract
The present disclosure provides wet processing systems and methods for improving etch uniformity across a semiconductor substrate when etching a silicon surface with a hydrofluoric acid (HF) and nitric acid (HNO3) etch solution (otherwise referred to herein as an HF+HNO3 etch solution). More specifically, the present disclosure provides single wafer wet processing systems and methods that improve etch uniformity across a silicon surface of a semiconductor substrate by increasing the concentration of nitrous acid (HNO2) in the HF+HNO3 etch solution used to etch the silicon surface prior to dispensing the HF+HNO3 etch solution onto the silicon surface.
Claims20
A method for improving etch uniformity across a semiconductor substrate, the method comprising:
- receiving the semiconductor substrate, the semiconductor substrate having a silicon-containing material exposed on a surface of the semiconductor substrate;
- dispensing an etch solution onto the surface of the semiconductor substrate while the semiconductor substrate is spinning at a rotational speed, the etch solution comprising a mixture of hydrofluoric acid (HF) and nitric acid (HNO3);
- and
- increasing a concentration of nitrous acid (HNO2) within the etch solution prior to dispensing the etch solution onto the surface of the semiconductor substrate to improve etch uniformity of the silicon-containing material across the semiconductor substrate, wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises exposing the etch solution to ultra-violet (UV) radiation or exposing the etch solution to a noble metal surface.
A method for improving etch uniformity across a semiconductor substrate, the method comprising:
- receiving the semiconductor substrate, the semiconductor substrate having a silicon-containing material exposed on a surface of the semiconductor substrate;
- dispensing an etch solution onto the surface of the semiconductor substrate while the semiconductor substrate is spinning at a rotational speed, the etch solution comprising a mixture of hydrofluoric acid (HF) and nitric acid (HNO3);
- and
- increasing a concentration of nitrous acid (HNO2) within the etch solution prior to dispensing the etch solution onto the surface of the semiconductor substrate to improve etch uniformity of the silicon-containing material across the semiconductor substrate, wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises:
- exposing the etch solution to ultra-violet (UV) radiation, wherein the UV radiation photolyzes the nitric acid (HNO3) in the etch solution into nitrous acid (HNO2) to increase the concentration of nitrous acid (HNO2) in the etch solution.
A method for improving etch uniformity across a semiconductor substrate, the method comprising:
- receiving the semiconductor substrate, the semiconductor substrate having a silicon-containing material exposed on a surface of the semiconductor substrate;
- dispensing an etch solution onto the surface of the semiconductor substrate while the semiconductor substrate is spinning at a rotational speed, the etch solution comprising a mixture of hydrofluoric acid (HF) and nitric acid (HNO3);
- and
- increasing a concentration of nitrous acid (HNO2) within the etch solution prior to dispensing the etch solution onto the surface of the semiconductor substrate to improve etch uniformity of the silicon-containing material across the semiconductor substrate, wherein said increasing the concentration of nitrous acid (HNO2) within the etch solution comprises:
- exposing the etch solution to a noble metal surface, wherein the noble metal surface catalyzes a reaction that converts a portion of the nitric acid (HNO3) in the etch solution into nitrous acid (HNO2) to increase the concentration of nitrous acid (HNO2) in the etch solution.
Dependencies are inferred from the claim text.