Cleaning and drying method and apparatus
View Patent ↗A method of cleaning semiconductor wafers before the epitaxial deposition comprising (A) etching silicon wafers with HF; (B) rinsing the etched wafers with ozonated ultrapure water; (C) treating the rinsed wafers with dilute SC1; (D) rinsing the treated wafers; (E) treating the wafers with dilute HF; (F) rinsing the wafers with DI water; (G) drying the wafers with nitrogen and a trace amount of IPA; wherein steps (E) through (G) are conducted in a single dryer chamber and wafers are not removed from the chamber between steps. A system comprising a single tank adapted for cleaning, etching, rinsing, and drying the wafers has means to inject HF into a DI water stream.
1. A method of cleaning semiconductor wafers before the epitaxial deposition step comprising: (A) etching silicon wafers with HF solution; (B) rinsing the etched wafers with ultrapure ozonated water; (C) treating the rinsed wafers with dilute SC1 solution having ammonium hydroxide content at about 1.5% or less by weight; (D) rinsing the treated wafers; (E) treating the wafers with dilute HF solution; (F) rinsing the wafers with DI water; (G) drying the wafers with nitrogen and a trace amount of IPA; wherein steps (E) through (G) are conducted in a single dryer chamber and wafers are not removed from the chamber between steps.
2. Method of claim 1 wherein the HF solution in step (A) is a solution of 0.5 to 5% by weight HF in water.
3. Method of claim 1 wherein the dilute HF solution in step (E) is a solution of 0.05 to 0.25% by weight HF in water.
4. Method of claim 1 wherein the dilute SC1 solution is a solution of 0.1 to 0.5% by weight ammonium hydroxide and about 0.1 to 1% by weight hydrogen peroxide.
5. Method of claim 1 wherein the ozonated water in the rinse of step (B) comprises less than about 10 part per million (ppm) ozone in water.
6. Method of claim 1 wherein dissolved oxygen (DO2) is controlled at less than 1 part per billion (ppb) in water.
7. Method of claim 1 wherein total organic carbon (TOC) is less than about 1 ppb in water.
8. Method of claim 1 wherein total dissolved silica is less than about 1 ppb in water.