Method for detecting variation of oxygen in gaps of lightly doped silicon single crystals in batches

Abstract

The method for batch detection of the interstitial oxygen variation of the lightly doped silicon single crystal provided by the invention comprises the following steps: obtaining a data distribution diagram of an interstitial oxygen initial value and the interstitial oxygen variation through a sample experiment, and obtaining a relationship between the interstitial oxygen initial value and the interstitial oxygen variation according to a data distribution rule of the data distribution diagram, the data distribution diagram can be divided into a first part and a second part, the interstitial oxygen variation in the first part is stabilized in a preset range, the second part can obtain an interstitial oxygen initial value and a trend formula of the interstitial oxygen variation, the interstitial oxygen initial value of the silicon wafer to be detected is detected, and when the interstitial oxygen initial value belongs to the first part, the interstitial oxygen variation of the silicon wafer to be detected is determined. When the interstitial oxygen initial value belongs to the first part, the interstitial oxygen variation of the to-be-detected silicon wafer is within the preset range, and when the interstitial oxygen initial value belongs to the second part, the interstitial oxygen initial value is substituted into the tendency formula to obtain the interstitial oxygen variation of the to-be-detected silicon wafer, batch detection of the to-be-detected silicon wafer is completed according to the mode, and the labor intensity of detection personnel is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of silicon single crystal quality detection, and in particular to a method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals. Background Art

[0002] Silicon single crystals account for a large proportion in the semiconductor industry. When the CZ method is used to pull silicon single crystals, a quartz crucible is used as a container for molten polysilicon. The main component of the quartz crucible is SiO2. When a certain temperature is reached, the quartz crucible will decompose oxygen and diffuse into the silicon single crystal to become interstitial oxygen. Interstitial oxygen becomes one of the most important impurities in silicon single crystals and directly affects the quality of silicon single crystals. After heat treatment, the interstitial oxygen in the silicon single crystal will form oxygen precipitation. At this time, the interstitial oxygen content of the silicon single crystal will decrease accordingly. Therefore, the interstitial oxygen change of the silicon single crystal after heat treatment will have a great influence on the performance of the device. Therefore, the interstitial oxygen change is of great help to technicians in judging the quality of silicon single crystals.

[0003] The existing method for detecting the change in interstitial oxygen of silicon single crystals is to detect the initial interstitial oxygen content value of the silicon wafer before heat treatment and the residual interstitial oxygen content value after heat treatment, and subtract the initial interstitial oxygen content value from the residual interstitial oxygen content value to obtain the interstitial oxygen change. However, when it is necessary to detect the change in interstitial oxygen of a batch of silicon single crystals, the inspector needs to detect the initial interstitial oxygen content value and the residual interstitial oxygen content value of each silicon wafer, which results in a high labor intensity for the inspector. Summary of the invention

[0004] In view of this, in order to address the above shortcomings, it is necessary to propose a method for batch detection of interstitial oxygen changes in lightly doped silicon single crystals to solve the technical problem of high labor intensity for detection personnel.

[0005] A method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals comprises the following steps: Step 1: obtain a data distribution diagram of the initial value of interstitial oxygen and the change in interstitial oxygen through a sample experiment, and obtain the relationship between the initial value of interstitial oxygen and the change in interstitial oxygen according to the data distribution law of the data distribution diagram. The sample experiment steps are specifically as follows: S1: Select several sample silicon wafers; S2: Performing initial interstitial oxygen detection on several sample silicon wafers respectively to obtain the initial interstitial oxygen value of each sample silicon wafer; S3: several sample silicon wafers are treated with the same heat treatment process to obtain treated silicon wafers; S4: performing residual interstitial oxygen detection on several processed silicon wafers respectively to obtain a residual interstitial oxygen value of each processed silicon wafer; S5: subtracting the interstitial oxygen initial value and the interstitial oxygen residual value of the same silicon wafer obtained above to obtain the interstitial oxygen change of the same silicon wafer; S6: A data distribution diagram is made for the interstitial oxygen initial values ​​of the several silicon wafers and the interstitial oxygen changes of the several silicon wafers obtained above. According to the data distribution law of the interstitial oxygen initial values ​​in the data distribution diagram, the data distribution diagram can be divided into a first part and a second part. The interstitial oxygen change in the first part is stable within a predetermined range, and the interstitial oxygen initial values ​​and the interstitial oxygen change in the second part are linearly distributed, so that a trend formula of the interstitial oxygen initial values ​​and the interstitial oxygen change can be obtained; Step 2: Detect the initial value of the gap oxygen of each silicon wafer to be tested. When the initial value of the gap oxygen belongs to the first part of the data distribution diagram, the gap oxygen change of the silicon wafer to be tested is within a predetermined range. When the initial value of the gap oxygen belongs to the second part of the data distribution diagram, the initial value of the gap oxygen is substituted into the trend formula obtained above for calculation, thereby obtaining the gap oxygen change of the silicon wafer to be tested. The batch inspection of the silicon wafers to be tested is completed according to the above method.

[0006] Preferably, the predetermined range is less than (1 ppma-2 ppma), the initial value of interstitial oxygen in the first portion is less than (12 ppma-13 ppma), and the initial value of interstitial oxygen in the second portion is greater than (12 ppma-13 ppma).

[0007] Preferably, the heat treatment process includes a first heat treatment, a second heat treatment, and a third heat treatment performed sequentially; The first heat treatment specifically includes: placing the sample silicon wafer in a first predetermined gas atmosphere, heating it to a first predetermined temperature at a first predetermined heating rate, introducing a second predetermined gas, and reacting for a first predetermined time to allow the interstitial oxygen in the silicon wafer to fully nucleate; The second heat treatment specifically comprises: heating the sample silicon wafer after the first heat treatment to a second predetermined temperature at a second predetermined heating rate and reacting for a second predetermined time, so that the interstitial oxygen in the silicon wafer nucleates and grows completely to form oxygen precipitates; The third heat treatment is specifically as follows: cooling the sample silicon wafer after the second heat treatment to a third predetermined temperature at a third predetermined cooling rate, introducing a third predetermined gas to stabilize the interstitial oxygen and oxygen precipitation in the silicon wafer, preventing the generation of impurities that affect the detection of the remaining interstitial oxygen, and obtaining a processed silicon wafer.

[0008] Preferably, in the first heat treatment, the first predetermined gas is nitrogen, the first predetermined heating rate is 80-90° C. / s, the first predetermined temperature is 700-800° C., the second predetermined gas is dry oxygen, and the first predetermined time is 1-3 h.

[0009] Preferably, in the second heat treatment, the second predetermined heating rate is 30-35° C. / min, the second predetermined temperature is 900-1100° C., and the second predetermined time is 18-20 h.

[0010] Preferably, in the third heat treatment, the third predetermined cooling rate is 25-30° C. / min, the third predetermined temperature is 700-800° C., and the third predetermined gas is nitrogen.

[0011] Preferably, the step S2 further includes a polishing step, and the polishing step specifically includes: placing the sample silicon wafer in a mixed acid solution for cleaning to remove a damaged layer on the surface of the sample silicon wafer.

[0012] Preferably, in the polishing step, the mixed acid solution consists of acetic acid, hydrofluoric acid and nitric acid, wherein the volume ratio of acetic acid, hydrofluoric acid and nitric acid is 1:1:(3-5), and the cleaning time is 1-2 min.

[0013] Preferably, the step S4 further includes a film removal step, and the film removal step specifically includes: placing the treated silicon wafer in a hydrofluoric acid solution for etching to remove the oxide layer on the surface of the treated silicon wafer.

[0014] Preferably, the concentration of the hydrofluoric acid solution is 45%-49%, and the corrosion time is 5-10 minutes.

[0015] It can be seen from the above technical scheme that the method provided by the present invention for batch detecting the change in interstitial oxygen of lightly doped silicon single crystals is, firstly, a data distribution diagram of the initial value of interstitial oxygen and the change in interstitial oxygen is obtained through a sample experiment, and the relationship between the initial value of interstitial oxygen and the change in interstitial oxygen is obtained according to the data distribution law of the data distribution diagram. The sample experiment steps are specifically as follows: S1: Select several sample silicon wafers; S2: Performing initial interstitial oxygen detection on several sample silicon wafers respectively to obtain the initial interstitial oxygen value of each sample silicon wafer; S3: several sample silicon wafers are treated with the same heat treatment process to obtain treated silicon wafers; S4: performing residual interstitial oxygen detection on several processed silicon wafers respectively to obtain a residual interstitial oxygen value of each processed silicon wafer; S5: subtracting the interstitial oxygen initial value and the interstitial oxygen residual value of the same silicon wafer obtained above to obtain the interstitial oxygen change of the same silicon wafer; S6: A data distribution diagram is made for the interstitial oxygen initial values ​​of the several silicon wafers and the interstitial oxygen changes of the several silicon wafers obtained above. According to the data distribution law of the interstitial oxygen initial values ​​in the data distribution diagram, the data distribution diagram can be divided into a first part and a second part. The interstitial oxygen change in the first part is stable within a predetermined range, and the interstitial oxygen initial values ​​and the interstitial oxygen change in the second part are linearly distributed, so that a trend formula of the interstitial oxygen initial values ​​and the interstitial oxygen change can be obtained; Ultimately, the inspectors only need to detect the initial gap oxygen value of each silicon wafer to be inspected. When the initial gap oxygen value belongs to the first part of the data distribution diagram, the gap oxygen change of the silicon wafer to be inspected is within a predetermined range, and the inspectors can take the average value of the predetermined range as the gap oxygen change of the silicon wafer to be inspected. When the initial gap oxygen value belongs to the second part of the data distribution diagram, the initial gap oxygen value is substituted into the trend formula obtained above for calculation, thereby obtaining the gap oxygen change of the silicon wafer to be inspected. According to the above method, batch inspection of silicon wafers to be inspected is completed, and there is no need to detect the gap oxygen residual value of each silicon wafer to be inspected, which greatly reduces the labor intensity of inspectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flow chart of a method for batch detecting interstitial oxygen changes in lightly doped silicon single crystals provided in an embodiment of the present invention.

[0017] Figure 2 This is a data distribution diagram of an embodiment of the method of the present invention. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Please see Figure 1 A method for batch detecting the change in interstitial oxygen of lightly doped silicon single crystals comprises the following steps: Step 1: obtain a data distribution diagram of the initial value of interstitial oxygen and the change in interstitial oxygen through a sample experiment, and obtain the relationship between the initial value of interstitial oxygen and the change in interstitial oxygen according to the data distribution law of the data distribution diagram. The sample experiment steps are specifically as follows: S1: Select several sample silicon wafers; S2: Performing initial interstitial oxygen detection on several sample silicon wafers respectively to obtain the initial interstitial oxygen value of each sample silicon wafer; S3: several sample silicon wafers are treated with the same heat treatment process to obtain treated silicon wafers; S4: performing residual interstitial oxygen detection on several processed silicon wafers respectively to obtain a residual interstitial oxygen value of each processed silicon wafer; S5: subtracting the interstitial oxygen initial value and the interstitial oxygen residual value of the same silicon wafer obtained above to obtain the interstitial oxygen change of the same silicon wafer; S6: A data distribution diagram is made for the interstitial oxygen initial values ​​of the several silicon wafers and the interstitial oxygen changes of the several silicon wafers obtained above. According to the data distribution law of the interstitial oxygen initial values ​​in the data distribution diagram, the data distribution diagram can be divided into a first part and a second part. The interstitial oxygen change in the first part is stable within a predetermined range, and the interstitial oxygen initial values ​​and the interstitial oxygen change in the second part are linearly distributed, so that a trend formula of the interstitial oxygen initial values ​​and the interstitial oxygen change can be obtained; Step 2: Detect the initial value of the gap oxygen of each silicon wafer to be tested. When the initial value of the gap oxygen belongs to the first part of the data distribution diagram, the gap oxygen change of the silicon wafer to be tested is within a predetermined range. When the initial value of the gap oxygen belongs to the second part of the data distribution diagram, the initial value of the gap oxygen is substituted into the trend formula obtained above for calculation, thereby obtaining the gap oxygen change of the silicon wafer to be tested. The batch inspection of the silicon wafers to be tested is completed according to the above method.

[0020] Compared with the prior art, the present invention has the following beneficial effects: First, a data distribution diagram of the initial value of interstitial oxygen and the change in interstitial oxygen is obtained by selecting a small number of sample silicon wafers and conducting a sample experiment. According to the data distribution law of the initial value of interstitial oxygen in the data distribution diagram, the data distribution diagram can be divided into a first part and a second part. The change in interstitial oxygen in the first part is stable within a predetermined range, while the initial value of interstitial oxygen and the change in interstitial oxygen in the second part are linearly distributed, so that a trend formula of the initial value of interstitial oxygen and the change in interstitial oxygen can be obtained. Finally, the inspector only needs to detect the initial value of interstitial oxygen of each silicon wafer to be inspected. When the initial value of interstitial oxygen belongs to the first part of the data distribution diagram, the change in interstitial oxygen of the silicon wafer to be inspected is within the predetermined range. The inspector can take the average value of the predetermined range as the change in interstitial oxygen of the silicon wafer to be inspected. When the initial value of interstitial oxygen belongs to the second part of the data distribution diagram, the initial value of interstitial oxygen is brought into the trend formula obtained above for calculation, so as to obtain the change in interstitial oxygen of the silicon wafer to be inspected. According to the above method, batch inspection of silicon wafers to be inspected can be completed, and it is no longer necessary to detect the residual value of interstitial oxygen of each silicon wafer to be inspected, which greatly reduces the labor intensity of the inspector.

[0021] There are more impurities in medium-doped silicon wafers and heavily-doped silicon wafers, and fewer impurities in lightly-doped silicon wafers. When the medium-doped silicon wafers and heavily-doped silicon wafers are used to detect the change in interstitial oxygen through the above sample experiment, the initial interstitial oxygen value and the residual interstitial oxygen value obtained will have large errors due to the large amount of impurities, affecting the accuracy of the change in interstitial oxygen. Therefore, the above sample experiment is suitable for lightly-doped silicon wafers.

[0022] In one embodiment, the predetermined range is less than (1 ppma-2 ppma), the initial value of interstitial oxygen of the first portion is less than (12 ppma-13 ppma), and the initial value of interstitial oxygen of the second portion is greater than (12 ppma-13 ppma).

[0023] In one embodiment, the heat treatment process includes a first heat treatment, a second heat treatment, and a third heat treatment performed sequentially; The first heat treatment specifically includes: placing the sample silicon wafer in a first predetermined gas atmosphere, heating it to a first predetermined temperature at a first predetermined heating rate, introducing a second predetermined gas, and reacting for a first predetermined time to allow the interstitial oxygen in the silicon wafer to fully nucleate; The second heat treatment specifically comprises: heating the sample silicon wafer after the first heat treatment to a second predetermined temperature at a second predetermined heating rate and reacting for a second predetermined time, so that the interstitial oxygen in the silicon wafer nucleates and grows completely to form oxygen precipitates; The third heat treatment is specifically as follows: cooling the sample silicon wafer after the second heat treatment to a third predetermined temperature at a third predetermined cooling rate, introducing a third predetermined gas to stabilize the interstitial oxygen and oxygen precipitation in the silicon wafer, preventing the generation of impurities that affect the detection of the remaining interstitial oxygen, and obtaining a processed silicon wafer.

[0024] In one embodiment, in the first heat treatment, the first predetermined gas is nitrogen, the first predetermined heating rate is 80-90°C / s, the first predetermined temperature is 700-800°C, the second predetermined gas is dry oxygen, and the first predetermined time is 1-3h.

[0025] In one embodiment, in the second heat treatment, the second predetermined heating rate is 30-35° C. / min, the second predetermined temperature is 900-1100° C., and the second predetermined time is 18-20 h.

[0026] In one embodiment, in the third heat treatment, the third predetermined cooling rate is 25-30° C. / min, the third predetermined temperature is 700-800° C., and the third predetermined gas is nitrogen.

[0027] In one embodiment, step S2 further includes a polishing step, wherein the polishing step is specifically: placing the sample silicon wafer in a mixed acid solution for cleaning to remove the damaged layer on the surface of the sample silicon wafer to prevent the damaged layer from affecting the interstitial oxygen nucleation and growth of the sample silicon wafer during the heat treatment process to form oxygen precipitation.

[0028] In one embodiment, in the polishing step, the mixed acid solution consists of acetic acid, hydrofluoric acid and nitric acid, wherein the volume ratio of acetic acid, hydrofluoric acid and nitric acid is 1:1:(3-5), and the cleaning time is 1-2 min.

[0029] In one embodiment, the step S4 further includes a film removal step, and the film removal step is specifically: placing the processed silicon wafer in a hydrofluoric acid solution for corrosion to remove the oxide layer on the surface of the processed silicon wafer to prevent the oxide layer from affecting the residual interstitial oxygen detection.

[0030] In one embodiment, the concentration of the hydrofluoric acid solution is 45%-49%, and the corrosion time is 5-10 minutes.

[0031] The following examples of the method of the present invention are used to demonstrate the implementation process of batch detection of changes in interstitial oxygen in silicon single crystals.

[0032] S1: Select five lightly boron-doped and five lightly phosphorus-doped crystal rods respectively, cut a 1mm thick silicon wafer from each crystal rod at an interval of 300mm, and engrave each silicon wafer to obtain a sample silicon wafer; Polishing step: place the sample silicon wafer in an etching basket, immerse the etching basket in the mixed acid solution for 1-2 minutes, perform mixed acid polishing on the sample silicon wafer to remove the damaged layer on the surface of the sample silicon wafer, and then immediately transfer it to the overflow tank for cleaning to remove the residual mixed acid solution. The mixed acid solution is composed of acetic acid, hydrofluoric acid and nitric acid, wherein the volume ratio of acetic acid, hydrofluoric acid and nitric acid is 1:1:5, the concentration of acetic acid is 99%, the concentration of hydrofluoric acid is 49%, and the concentration of nitric acid is 70%.

[0033] S2: Place the sample silicon wafer in the basket of the FT-IR light oxygen doping detector, input the engraving code of the sample silicon wafer into the system in order, select the recipe with a diameter of nine points for testing, and obtain the initial value of interstitial oxygen of each sample silicon wafer.

[0034] S3: Place the sample silicon wafer in a heat treatment furnace, introduce 50 bar of nitrogen into the heat treatment furnace, quickly heat the heat treatment furnace to 700-800°C at a rate of 85°C / s, then introduce 60 bar of dry oxygen, and perform the first heat treatment in a dry oxygen atmosphere at a constant temperature for 2 hours, then heat the furnace to 900-1100°C at a rate of 30°C / min and maintain the temperature for 18-20 hours for the second heat treatment, then cool the furnace to 700°C at a rate of 30°C / min, turn off the dry oxygen, and introduce 50 bar of nitrogen for the third heat treatment to obtain a treated silicon wafer.

[0035] Film removal step: Place the treated silicon wafer in a corrosion basket, and place the corrosion basket in a 45%-49% HF solution for corrosion for 5-10 minutes. Remove the oxide layer on the surface of the treated silicon wafer, take it out, rinse it with deionized water, and transfer it to the detection room.

[0036] S4: Place the processed silicon wafer in the basket of the FT-IR light oxygen doping detector, input the engraved code of the processed silicon wafer into the system in sequence, select the recipe with a diameter of nine points for testing, and obtain the interstitial oxygen residual value of each processed silicon wafer.

[0037] S5: performing data sorting, and subtracting the interstitial oxygen initial value and the interstitial oxygen residual value of the same silicon wafer obtained above to obtain the interstitial oxygen change of the same silicon wafer.

[0038] S6: Draw a data distribution diagram for the initial interstitial oxygen values ​​of the several silicon wafers and the interstitial oxygen changes of the several silicon wafers obtained above, such as Figure 2 As shown, according to the data distribution law of the initial value of interstitial oxygen in the data distribution diagram, the data distribution diagram can be divided into a first part and a second part. The change in interstitial oxygen in the first part is stable within a predetermined range of 0-2ppma, and the initial value of interstitial oxygen and the change in interstitial oxygen in the second part are linearly distributed, so that the trend formula of the initial value of interstitial oxygen and the change in interstitial oxygen can be obtained.

[0039] Depend on Figure 2 It is concluded that the initial value of interstitial oxygen in the first part is less than 12 ppma, and the initial value of interstitial oxygen in the second part is greater than 12 ppma. The initial value of interstitial oxygen in the second part and the change in interstitial oxygen can be linearly fitted, so that the trend formula of the initial value of interstitial oxygen and the change in interstitial oxygen can be obtained as y = 3.3058x -39.807, R 2 =0.9353, where y is the change in interstitial oxygen, x is the initial value of interstitial oxygen, R 2 The coefficient of determination indicates the closeness between the estimated value of the trend line and the actual data. It is a measure of the reliability of the trend line. 2 When it is close to 1, the trend formula is most reliable, and the R of the trend line 2 When it is close to 0, the reliability of the trend formula is the smallest. Therefore, when it is necessary to batch test the interstitial oxygen change of lightly doped silicon single crystals, it is only necessary to detect the initial interstitial oxygen value of each silicon wafer to be tested. When the initial interstitial oxygen value belongs to the first part of the data distribution diagram, the interstitial oxygen change is stable within a predetermined range. The tester can take the average value of the predetermined range as the interstitial oxygen change of the silicon wafer to be tested. When the initial interstitial oxygen value belongs to the second part of the data distribution diagram, the initial interstitial oxygen value is substituted into the trend formula obtained above to obtain the interstitial oxygen change of the silicon wafer to be tested. According to the above method, batch testing of silicon wafers to be tested is completed, and it is no longer necessary to detect the interstitial oxygen residual value of each silicon wafer to be tested, which greatly reduces the labor intensity of the testers.

[0040] The modules or units in the device of the embodiment of the present invention can be combined, divided and deleted according to actual needs. The above disclosure is only the preferred embodiment of the present invention, and of course it cannot be used to limit the scope of the rights of the present invention. Those skilled in the art can understand that all or part of the processes of the above embodiment are implemented, and the equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for batch detection of interstitial oxygen changes in lightly doped silicon single crystals, characterized in that: The following steps are involved: Step 1: obtain a data distribution diagram of the initial value of interstitial oxygen and the change in interstitial oxygen through a sample experiment, and obtain the relationship between the initial value of interstitial oxygen and the change in interstitial oxygen according to the data distribution law of the data distribution diagram. The sample experiment steps are specifically as follows: S1: Select several sample silicon wafers; S2: Performing initial interstitial oxygen detection on several sample silicon wafers respectively to obtain the initial interstitial oxygen value of each sample silicon wafer; S3: several sample silicon wafers are treated with the same heat treatment process to obtain treated silicon wafers; S4: performing residual interstitial oxygen detection on several processed silicon wafers respectively to obtain a residual interstitial oxygen value of each processed silicon wafer; S5: subtracting the interstitial oxygen initial value and the interstitial oxygen residual value of the same silicon wafer obtained above to obtain the interstitial oxygen change of the same silicon wafer; S6: A data distribution diagram is made for the interstitial oxygen initial values ​​of the several silicon wafers and the interstitial oxygen changes of the several silicon wafers obtained above. According to the data distribution law of the interstitial oxygen initial values ​​in the data distribution diagram, the data distribution diagram can be divided into a first part and a second part. The interstitial oxygen change in the first part is stable within a predetermined range, and the interstitial oxygen initial values ​​and the interstitial oxygen change in the second part are linearly distributed, so that a trend formula of the interstitial oxygen initial values ​​and the interstitial oxygen change can be obtained; Step 2: Detect the initial value of the gap oxygen of each silicon wafer to be tested. When the initial value of the gap oxygen belongs to the first part of the data distribution diagram, the gap oxygen change of the silicon wafer to be tested is within a predetermined range. When the initial value of the gap oxygen belongs to the second part of the data distribution diagram, the initial value of the gap oxygen is substituted into the trend formula obtained above for calculation, thereby obtaining the gap oxygen change of the silicon wafer to be tested. The batch inspection of the silicon wafers to be tested is completed according to the above method.

2. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 1, characterized in that: The predetermined range is less than (1 ppma-2 ppma), the initial value of interstitial oxygen of the first portion is less than (12 ppma-13 ppma), and the initial value of interstitial oxygen of the second portion is greater than (12 ppma-13 ppma).

3. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 1, characterized in that: The heat treatment process includes a first heat treatment, a second heat treatment, and a third heat treatment performed sequentially; The first heat treatment specifically includes: placing the sample silicon wafer in a first predetermined gas atmosphere, heating it to a first predetermined temperature at a first predetermined heating rate, introducing a second predetermined gas, and reacting for a first predetermined time to allow the interstitial oxygen in the silicon wafer to fully nucleate; The second heat treatment specifically comprises: heating the sample silicon wafer after the first heat treatment to a second predetermined temperature at a second predetermined heating rate and reacting for a second predetermined time, so that the interstitial oxygen in the silicon wafer nucleates and grows completely to form oxygen precipitates; The third heat treatment is specifically as follows: cooling the sample silicon wafer after the second heat treatment to a third predetermined temperature at a third predetermined cooling rate, introducing a third predetermined gas to stabilize the interstitial oxygen and oxygen precipitation in the silicon wafer, preventing the generation of impurities that affect the detection of the remaining interstitial oxygen, and obtaining a processed silicon wafer.

4. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 3, characterized in that: In the first heat treatment, the first predetermined gas is nitrogen, the first predetermined heating rate is 80-90° C. / s, the first predetermined temperature is 700-800° C., the second predetermined gas is dry oxygen, and the first predetermined time is 1-3 h.

5. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 3, characterized in that: In the second heat treatment, the second predetermined heating rate is 30-35° C. / min, the second predetermined temperature is 900-1100° C., and the second predetermined time is 18-20 h.

6. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 3, characterized in that: In the third heat treatment, the third predetermined cooling rate is 25-30° C. / min, the third predetermined temperature is 700-800° C., and the third predetermined gas is nitrogen.

7. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 1, characterized in that: The step S2 also includes a polishing step, which specifically includes: placing the sample silicon wafer in a mixed acid solution for cleaning to remove the damaged layer on the surface of the sample silicon wafer.

8. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 7, characterized in that: In the polishing step, the mixed acid solution is composed of acetic acid, hydrofluoric acid and nitric acid, wherein the volume ratio of acetic acid, hydrofluoric acid and nitric acid is 1:1:(3-5), and the cleaning time is 1-2 minutes.

9. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 1, characterized in that: The step S4 also includes a film removal step, which specifically includes: placing the processed silicon wafer in a hydrofluoric acid solution for etching to remove the oxide layer on the surface of the processed silicon wafer.

10. The method for batch detecting interstitial oxygen variation of lightly doped silicon single crystals according to claim 9, characterized in that: The concentration of the hydrofluoric acid solution is 45%-49%, and the corrosion time is 5-10 minutes.

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