Silicon wafer defect detection method

Abstract

The invention relates to a silicon wafer defect detection method, which belongs to the technical field of silicon wafer processing inspection, and comprises the following operation steps: 1, cutting a sample with a certain thickness from a to-be-detected material, and carrying out surface grinding and cleaning treatment to complete a sample preparation process; 2, the cleaned sample is subjected to thermal oxidation treatment, the thermal oxidation treatment is divided into multiple stages, and different temperatures and time are set in each stage; and 3, deoxidizing the sample subjected to thermal oxidation treatment by using a hydrofluoric acid solution so as to remove a surface oxide layer and expose microdefects. And 4, putting the deoxidized sample into a preferred corrosive liquid for corrosion treatment. And 5, observing the corroded sample by using a metallographic microscope or X-ray diffraction morphology, determining the type and distribution of the defects, and recording and analyzing the type, density and distribution condition of the micro-defects. The detection success rate can be effectively improved, the detection result is visualized, and the environmental pollution is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of silicon wafer processing inspection, and in particular to a method for detecting silicon wafer defects. Background Art

[0002] In the semiconductor material manufacturing process, micro defect detection of materials such as single crystal silicon is an important link to ensure product quality. Traditional detection methods such as chemical etching have problems such as low detection rate, poor effect on specific materials (such as heavily doped arsenic low resistivity silicon single crystal), and environmental pollution. Summary of the invention

[0003] The present invention mainly solves the deficiencies in the prior art and provides a method for detecting silicon wafer defects, which has the advantages of intuitive detection results, high detection success rate and good detection stability, and solves the problems of poor detection efficiency and environmental pollution of silicon wafer micro-defects. It can effectively improve the detection success rate, realize intuitive detection results, and reduce environmental pollution.

[0004] The above technical problems of the present invention are mainly solved by the following technical solutions: A method for detecting silicon wafer defects comprises the following steps: Step 1: Cut a sample of a certain thickness from the material to be tested, and perform surface grinding and cleaning to obtain a flat and clean surface to complete the sample preparation process.

[0005] Step 2: The cleaned samples are subjected to thermal oxidation treatment. The thermal oxidation treatment is divided into multiple stages, and different temperatures and times are set for each stage.

[0006] Step 3: Deoxidize the samples after thermal oxidation treatment using hydrofluoric acid solution to remove the surface oxide layer and expose micro defects.

[0007] Step 4: Place the deoxidized sample in a selective etching solution for etching, so as to magnify and clearly display micro defects.

[0008] Step 5: Use a metallographic microscope or X-ray diffraction morphology to observe the corroded samples, determine the type and distribution of defects, and record and analyze the type, density and distribution of micro defects.

[0009] Preferably, the first stage is maintained at a constant temperature of 950°C for 60 minutes, the second stage is maintained at 1100°C for 120 minutes, and the third stage is further reduced to 950°C for 60 minutes.

[0010] Preferably, in the first stage, the temperature is increased to 950°C at a rate of 5°C / min; after keeping warm for a period of time, the temperature is increased to the second stage of 1100°C at a rate of 5°C / min; after keeping warm, the temperature is lowered to the third stage temperature of 950°C at a rate of 3°C / min, and naturally cooled to room temperature after the insulation is completed.

[0011] Preferably, the sample is placed in a thermal oxidation furnace, wet oxygen is used as the oxidizing gas, and the oxygen flow rate is controlled at 45 lpm.

[0012] Preferably, the sample after thermal oxidation treatment is immersed in a hydrofluoric acid solution with a concentration of 40% to 50% for 23 minutes to remove the surface oxide layer.

[0013] Preferably, the corrosion solution is prepared by mixing chromium trioxide, copper nitrate, nitric acid, acetic acid and hydrofluoric acid solution.

[0014] Preferably, a sample with a thickness of 13 mm is cut from a single crystal silicon rod and cut using a diamond wire saw or a band saw. The sample is then surface ground to remove approximately 0.21 mm and then ultrasonically cleaned using alcohol or deionized water to ensure that the sample surface is flat and clean.

[0015] The present invention can achieve the following effects: The present invention provides a method for detecting silicon wafer defects. Compared with the prior art, the method has the advantages of intuitive detection results, high detection success rate, reduced environmental pollution and good detection stability, and solves the problems of poor efficiency and environmental pollution in silicon wafer micro-defect detection. Through segmented thermal oxidation treatment, micro-defects can be effectively amplified to improve the accuracy and success rate of detection. Observation with a metallographic microscope or X-ray diffraction morphology can intuitively display the morphology and distribution of micro-defects. Compared with the traditional chemical corrosion method, the use of harmful chemical reagents is reduced, and the pollution to the environment is reduced. DETAILED DESCRIPTION

[0016] The technical solution of the invention is further specifically described below through embodiments.

[0017] Embodiment: A method for detecting silicon wafer defects comprises the following steps: Step 1: Cut a sample of a certain thickness from the material to be tested, and perform surface grinding and cleaning to obtain a flat and clean surface to complete the sample preparation process.

[0018] A sample with a thickness of 13 mm is cut from a single crystal silicon rod and cut using a diamond wire saw or a band saw. The sample is then surface ground to remove approximately 0.21 mm, and then ultrasonically cleaned using alcohol or deionized water to ensure that the sample surface is flat and clean.

[0019] Step 2: The cleaned samples are thermally oxidized. The thermal oxidation treatment is divided into multiple stages, with different temperatures and times set for each stage. The samples are placed in a thermal oxidation furnace, using wet oxygen as the oxidizing gas, and the oxygen flow rate is controlled at 45 lpm.

[0020] The first stage is to maintain a constant temperature at 950°C for 60 minutes, the second stage is to maintain a temperature at 1100°C for 120 minutes, and the third stage is to drop the temperature to 950°C for 60 minutes.

[0021] In the first stage, the temperature is increased to 950°C at a rate of 5°C / min; after keeping warm for a period of time, the temperature is increased to the second stage of 1100°C at a rate of 5°C / min; after keeping warm, the temperature is lowered to the third stage temperature of 950°C at a rate of 3°C / min, and naturally cooled to room temperature after the insulation is completed.

[0022] Step 3: Deoxidize the samples after thermal oxidation treatment using hydrofluoric acid solution to remove the surface oxide layer and expose micro defects. Immerse the samples after thermal oxidation treatment in a hydrofluoric acid solution with a concentration of 40% to 50% for 23 minutes to remove the surface oxide layer.

[0023] Step 4: Place the deoxidized sample in a selective etching solution for etching, so as to magnify and clearly show micro defects. The selective etching solution is a mixture of chromium trioxide, copper nitrate, nitric acid, acetic acid and hydrofluoric acid solution.

[0024] Step 5: Use a metallographic microscope or X-ray diffraction morphology to observe the corroded samples, determine the type and distribution of defects, and record and analyze the type, density and distribution of micro defects.

[0025] In summary, the silicon wafer defect detection method has the advantages of intuitive detection results, high detection success rate, reduced environmental pollution and good detection stability, which solves the problems of poor efficiency and environmental pollution in silicon wafer micro-defect detection. Through segmented thermal oxidation treatment, micro-defects can be effectively amplified to improve the accuracy and success rate of detection. Observation with a metallographic microscope or X-ray diffraction morphology can intuitively display the morphology and distribution of micro-defects. Compared with traditional chemical corrosion methods, the use of harmful chemical reagents is reduced, and the pollution to the environment is reduced.

[0026] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are included in the patent scope of the present invention.

Claims

1. A method for detecting silicon wafer defects, characterized in that The steps are as follows: Step 1: Cut a sample of a certain thickness from the material to be tested, and grind and clean the surface to obtain a flat and clean surface to complete the sample preparation process; Step 2: The cleaned samples are subjected to thermal oxidation treatment. The thermal oxidation treatment is divided into multiple stages, and different temperatures and times are set for each stage. Step 3: Deoxidize the samples after thermal oxidation treatment using hydrofluoric acid solution to remove the surface oxide layer and expose micro defects; Step 4: Place the deoxidized sample into a selective etching solution for corrosion treatment; Step 5: Use a metallographic microscope or X-ray diffraction morphology to observe the corroded samples, determine the type and distribution of defects, and record and analyze the type, density and distribution of micro defects.

2. The method for detecting silicon wafer defects according to claim 1, characterized in that: The first stage is to maintain a constant temperature at 950°C for 60 minutes, the second stage is to maintain a temperature at 1100°C for 120 minutes, and the third stage is to drop the temperature to 950°C for 60 minutes.

3. The method for detecting silicon wafer defects according to claim 2, characterized in that: In the first stage, the temperature is increased to 950°C at a rate of 5°C / min; after keeping warm for a period of time, the temperature is increased to the second stage of 1100°C at a rate of 5°C / min; after keeping warm, the temperature is lowered to the third stage temperature of 950°C at a rate of 3°C / min, and naturally cooled to room temperature after the insulation is completed.

4. The method for detecting silicon wafer defects according to claim 1, characterized in that: The samples were placed in a thermal oxidation furnace, using wet oxygen as the oxidizing gas, and the oxygen flow rate was controlled at 45 lpm.

5. The method for detecting silicon wafer defects according to claim 1, characterized in that: The samples after thermal oxidation treatment were immersed in a hydrofluoric acid solution with a concentration of 40% to 50% for 23 minutes to remove the surface oxide layer.

6. The method for detecting silicon wafer defects according to claim 1, characterized in that: The preferred etching solution is prepared by mixing chromium trioxide, copper nitrate, nitric acid, acetic acid and hydrofluoric acid solution.

7. The method for detecting silicon wafer defects according to claim 1, characterized in that: A sample with a thickness of 13 mm is cut from a single crystal silicon rod and cut using a diamond wire saw or a band saw. The sample is then surface ground to remove approximately 0.21 mm, and then ultrasonically cleaned using alcohol or deionized water to ensure that the sample surface is flat and clean.