Method for cleaning lanthanum gallium silicate wafer

Abstract

The present disclosure provides a method for cleaning a lanthanum gallium silicate wafer which comprises the following steps: at a step of 1, a cleaning solution constituted of phosphorous acid, hydrogen peroxide and deionized water is utilized to clean the lanthanum gallium silicate wafer with a megahertz sound wave; at a step of 2, the cleaned lanthanum gallium silicate wafer is rinsed and dried by spinning; at a step of 3, a cleaning solution constituted of ammonia, hydrogen peroxide and deionized water is utilized to clean the lanthanum gallium silicate wafer with the megahertz sound wave; at a step of 4, the cleaned lanthanum gallium silicate wafer is rinsed and dried by spinning; and at a step of 5, the rinsed and dried wafer is placed in an oven to be baked. The present invention shortens a period of acidic cleaning process and prolongs a period of alkaline cleaning and utilizes a more effective cleaning with megahertz sound wave to replace the conventional ultrasonic cleaning to solve the issue of cleaning the lanthanum gallium silicate wafer after a cutting process and to improve surface cleanliness of the lanthanum gallium silicate wafer to get a better cleaning effect.

Claims

1. A method for cleaning a lanthanum gallium silicate wafer comprising: at a step of 1, utilizing an acidic cleaning solution comprising phosphoric acid, hydrogen peroxide and deionized water to clean the lanthanum gallium silicate wafer with a megahertz sound wave; at a step of 2, rinsing and drying the cleaned lanthanum gallium silicate wafer by spinning; at a step of 3, utilizing an alkaline cleaning solution comprising ammonia, hydrogen peroxide and deionized water to clean the lanthanum gallium silicate wafer with the megahertz sound wave; at a step of 4, rinsing and drying the cleaned lanthanum gallium silicate wafer by spinning; and at a step of 5, baking the rinsed and dried wafer in an oven, wherein a time period for alkaline cleaning is longer than that for acidic cleaning, and wherein the method uses only phosphoric acid without using any other acid.

2. The method for cleaning a lanthanum gallium silicate wafer according to claim 1, wherein at the step of 1, the cleaning solution constituted of phosphoric acid, hydrogen peroxide and deionized water has a mass ratio of H.sub.3PO.sub.4:H.sub.2O.sub.2:H.sub.2O of 1:1:50100.

3. The method for cleaning a lanthanum gallium silicate wafer according to claim 1, wherein at the step of 1, the cleaning with the megahertz sound wave is implemented at a temperature of 5060 C. for 10 minutes.

4. The method for cleaning a lanthanum gallium silicate wafer according to claim 1, wherein at the step of 2, the lanthanum gallium silicate wafer is rinsed by deionized water at a room temperature for 10 minutes.

5. The method for cleaning a lanthanum gallium silicate wafer according to claim 1, wherein at the step of 3, the cleaning solution constituted of ammonia, hydrogen peroxide and deionized water has a mass ratio of NH.sub.3:H.sub.2O.sub.2:H.sub.2O of 1:2:50-100.

6. The method for cleaning a lanthanum gallium silicate wafer according to claim 1, wherein at the step of 3, the cleaning with the megahertz sound wave is implemented at a temperature of 50-60 C. for 50 minutes.

7. The method for cleaning a lanthanum gallium silicate wafer according to claim 1, wherein at the step of 4, the lanthanum gallium silicate wafer is rinsed by deionized water at a room temperature for 10 minutes.

8. The method for cleaning a lanthanum gallium silicate wafer according to claim 1, wherein at the step of 5, the lanthanum gallium silicate wafer is baked in a drying oven at a temperature of 40-90 C. for 20-30 minutes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to further illustrate contents of the present invention, the present invention will be illustrated in detail in conjunction with the accompany figures, in which:

(2) FIG. 1 is a schematic view of etched states of the lanthanum gallium silicate wafer by different acid solutions.

(3) FIG. 2 is a flow process chart of a cleaning process which is regularly used in a conventional silicon integrated circuit industry.

(4) FIG. 3 is a flow chart of a method for cleaning lanthanum gallium silicate wafer according to the present invention.

(5) FIG. 4 is a test image of a surface of the lanthanum gallium silicate wafer captured by an optical microscope before and after being cleaned by utilizing the present invention.

(6) FIG. 5 is a test image of a surface of the lanthanum gallium silicate wafer captured by an atom force microscope (AFM) before and after being cleaned by utilizing the present invention.

DETAILED DESCRIPTION

(7) In order to make the objective, technical solution and advantages of the present invention become apparent, the present invention will be further illustrated in detail with reference to accompany figures.

(8) FIG. 1 is a schematic view of etched states of the lanthanum gallium silicate wafer by different acid solutions, which shows that various acid solutions have certain etching effects on the lanthanum gallium silicate wafer, but the corrosivity of phosphoric acid is much weaker than that of the regularly used hydrochloric acid in the conventional cleaning solutions.

(9) FIG. 2 is a flow process chart of a cleaning process which is regularly used in a conventional silicon integrated circuit industry. As can be seen from FIG. 2, in the conventional cleaning process, hydrochloric acid is usually used as a primary component of the acidic cleaning solution, and the period for cleaning with the acidic cleaning solution is longer than the period for cleaning with the alkaline cleaning solution, and such a cleaning process may lead to corruption of the lanthanum gallium silicate. The conventional cleaning process utilizes an ultrasonic cleaning method, the effect of which is worse than that of the megahertz sound wave cleaning.

(10) FIG. 3 is a flow chart of a method for cleaning lanthanum gallium silicate wafer according to the present invention, which modifies the conventional cleaning process for characteristic of the lanthanum gallium silicate wafer. On the basis of the conventional method for cleaning the semiconductor wafer as shown in FIG. 2, the method utilizes phosphoric acid which has a weak corrosivity on the lanthanum gallium silicate wafer to replace the hydrochloric acid which has a strong corrosivity on the lanthanum gallium silicate wafer, so the period of acidic cleaning process is shorten and the period of alkalinous cleaning process is prolonged. Furthermore, a more effective megahertz sound wave cleaning process is utilized to replace the conventional ultrasonic cleaning. In particular, the method comprises the following steps.

(11) At a step of 1, a cleaning solution constituted of phosphoric acid, hydrogen peroxide and deionized water is utilized to clean the lanthanum gallium silicate wafer with a megahertz sound wave, in which the cleaning solution constituted of phosphoric acid, hydrogen peroxide and deionized water has a mass ratio of H3PO4:H2O2:H2O of 1:1:50100, and the cleaning method is the megahertz sound wave cleaning at a temperature of 5060 C. for 10 minutes.

(12) At a step of 2, the lanthanum gallium silicate wafer cleaned at the step of 1 is rinsed in the deionized water and is dried by spinning, in which the period for rinsing is 10 minutes.

(13) At a step of 3, a cleaning solution constituted of ammonia, hydrogen peroxide and deionized water is utilized to clean the lanthanum gallium silicate wafer with the megahertz sound wave, in which the cleaning solution constituted of ammonia, hydrogen peroxide and deionized water has a mass ratio of NH.sub.3:H.sub.2O.sub.2:H.sub.2O of 1:2:50-100, and the cleaning method is the megahertz sound wave cleaning at a temperature of 5060 C. for 50 minutes.

(14) At a step of 4, the lanthanum gallium silicate wafer cleaned at the step of 3 is rinsed in the deionized water and is dried by spinning, in which the period for rinsing is 10 minutes.

(15) At a step of 5, the wafer rinsed and dried at the step of 4 is placed in an oven to be baked, in which the lanthanum gallium silicate wafer is baked in a drying oven at a temperature of 40-90 C. for 20-30 minutes. Then, the whole cleaning process is ended.

(16) The present invention utilize the alkalinous hydrogen peroxide solution and the megahertz sound wave cleaning method to clean the lanthanum gallium silicate wafer by synthetically utilizing physical and chemical cleaning methods, so it effectively improve cleanness of the surface of the lanthanum gallium silicate wafer.

(17) FIG. 4 is a test image of a surface of the lanthanum gallium silicate wafer captured by an optical microscope before and after being cleaned by utilizing the present invention. As can be seen from FIG. 4, by utilizing the cleaning method of the present invention to clean the lanthanum gallium silicate wafer, an amount of the contaminants is decreased and the cleanness is improved. Thus, the method for cleaning the lanthanum gallium silicate wafer according to the present invention has an excellent cleaning effect and a higher cleanness.

(18) FIG. 5 is a test image of a surface of the lanthanum gallium silicate wafer captured by an atom force microscope (AFM) before and after being cleaned by utilizing the present invention. As can be seen from FIG. 5, the method for cleaning the lanthanum gallium silicate wafer of the present invention makes no damage on the lanthanum gallium silicate wafer and obtains a better cleaning effect.

(19) The particular embodiments as mentioned above further illustrate the objective, technical solution and advantages of the present invention in detail. It should be understood that the above descriptions are only particular embodiments of the present invention and are not intended to limit the present invention. All of the modifications, equivalent replacements and improvements within the spirit and principle of the present invention are included in the scope of the present invention.