Method for cleaning wafer and cleaning fluid for industrial use

Abstract

This invention discloses a method for cleaning wafers and a cleaning solution for industrial use. The method for cleaning wafers includes a first rinsing step, a second rinsing step, a rinsing step, and a drying step. The first rinsing step includes placing the wafer in the cleaning solution and rinsing it with an ultrasonic rinsing machine. The second rinsing step includes placing the wafer in a first treatment solution and rinsing it with an ultrasonic rinsing machine. The rinsing step includes placing the wafer in a container and rinsing it with a second treatment solution. The drying step includes drying the wafer with nitrogen gas. The cleaning solution includes a detergent and deionized water. The detergent includes a liquid mineral element composition, and the liquid mineral element composition includes sodium ions, potassium ions, and magnesium ions. The weight ratio of detergent to deionized water is between 1:4 and 1:10. The cleaning solution has a pH value between 6.8 and 9.8.

Claims

1. A method for cleaning a wafer, comprising: A first rinsing step: placing a wafer in a cleaning solution and rinsing the cleaning solution with an ultrasonic rinsing machine for a first rinsing time; wherein the cleaning solution comprises: a cleaning agent comprising a liquid mineral element composition, the liquid mineral element composition comprising sodium ions, potassium ions, and magnesium ions; and deionized water; wherein the weight ratio of the cleaning agent to the deionized water is between 1:4 and 1:10; wherein the cleaning solution has a pH value between 6.8 and 9.8; wherein the cleaning solution does not contain nonylphenol petrochemical surfactants, methane, formaldehyde, toluene, ether alcohols, and chlorofluorocarbons; and a second rinsing step: removing the wafer from the cleaning solution and placing the wafer in a first treatment solution, rinsing the first treatment solution with the ultrasonic rinsing machine for a second rinsing time; the first treatment solution is selected from deionized water; A rinsing step: the wafer is removed from the first treatment solution and placed in a container, and the wafer is rinsed with a second treatment solution at a rinsing time; the second treatment solution is selected from deionized water; and a drying step: the wafer is dried with nitrogen gas.

2. The method for cleaning a wafer as described in claim 1, wherein, Based on the total weight of the cleaning agent being 100 wt%, the content of the liquid mineral element composition is between 10 wt% and 50 wt%, and the content of sodium ions is between 0.1 and 0.5 wt%.

3. The method for cleaning a wafer as described in claim 1, wherein, In Fourier transform infrared spectroscopy, the cleaning solution does not have absorption peaks in the C=C stretching vibration region, the CF stretching vibration region, and the C-Cl stretching vibration region.

4. The method for cleaning a wafer as described in claim 1, wherein, The cleaning fluid has a temperature between 25°C and 50°C, and the first rinsing time is between 600 seconds and 1200 seconds; wherein the second rinsing time is between 60 seconds and 300 seconds; wherein the rinsing time is between 50 seconds and 70 seconds.

5. The method for cleaning a wafer as described in claim 1, wherein, The cleaning solution further comprises hydrogen peroxide and citric acid; based on a total weight of 100 wt% for the cleaning solution, the content of the liquid mineral element composition is between 0.1 wt% and 0.5 wt%, the content of deionized water is between 90 wt% and 95 wt%, the content of hydrogen peroxide is between 2 wt% and 4 wt%, and the content of citric acid is between 0.5 wt% and 1 wt%.

6. The method for cleaning a wafer as described in claim 1, wherein, The weight ratio of the liquid mineral element composition to the deionized water is between 1:7 and 1:

10.

7. The method for cleaning a wafer as described in claim 1, wherein, The concentration of sodium ions in the liquid mineral element composition is between 295 ppm and 750 ppm, the concentration of potassium ions is between 5 ppm and 30 ppm, and the concentration of magnesium ions is not greater than 0.5 ppm.

8. The method for cleaning a wafer as described in claim 7, wherein, The liquid mineral element composition further includes calcium ions and selenium ions, and the concentration of calcium ions is not greater than 1 ppm.

9. The method for cleaning a wafer as described in claim 8, wherein, The magnesium ions, potassium ions, calcium ions, and selenium ions have a concentration ratio of 4.0–6.0: 0.5–2.0: 0.5–2.0: 10⁻⁷ per mole.

10. The method for cleaning a wafer as described in claim 1, wherein, The liquid mineral element composition further includes bicarbonate ions, chloride ions, and sulfate ions, wherein the concentration of bicarbonate ions is between 50 ppm and 305 ppm, the concentration of chloride ions is between 60 ppm and 400 ppm, and the concentration of sulfate ions is between 400 ppm and 770 ppm.

11. The method for cleaning a wafer as described in claim 1, wherein, The cleaning solution further comprises a surfactant, which is selected from at least one of nonionic surfactants and biological surfactants.

12. The method for cleaning a wafer as described in claim 1, wherein, Prior to the first soaking step, the method of cleaning the wafer with the cleaning solution further includes an soaking step: immersing the wafer in the cleaning solution for a period of time.

13. An industrial cleaning fluid that does not contain nonylphenol petrochemical surfactants, methane, formaldehyde, toluene, ether alcohols, or chlorofluorocarbons, said cleaning fluid comprising: A cleaning agent comprising a liquid mineral element composition; said liquid mineral element composition comprising sodium ions, potassium ions, and magnesium ions; The cleaning agent and deionized water are present in a weight ratio between 1:4 and 1:10; and the cleaning solution has a pH value between 6.8 and 9.8.

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