A method for detecting the bulk resistivity uniformity of lightly phosphorus-doped single-crystal silicon rods and wafers.

Abstract

This invention discloses a method for detecting the bulk resistivity uniformity of lightly phosphorus-doped monocrystalline silicon rods and wafers, belonging to the field of monocrystalline silicon rod technology. The method involves preparing the lightly phosphorus-doped monocrystalline silicon rods using the Czochralski method, uniformly doping them with light phosphorus via ion implantation. The detection method includes: axial bulk resistivity uniformity detection; slicing the lightly phosphorus-doped monocrystalline silicon rods; radial bulk resistivity uniformity detection; construction and uniformity determination of the three-dimensional bulk resistivity distribution; and data archiving and feedback. This invention solves the problem that existing technologies can only achieve single-dimensional detection and cannot comprehensively evaluate bulk resistivity uniformity. This invention can intuitively and comprehensively reflect the bulk resistivity distribution of lightly phosphorus-doped monocrystalline silicon rods and wafers, accurately locate areas with poor uniformity, avoid defect omissions caused by single-dimensional detection, and comprehensively evaluate bulk resistivity uniformity.

Description

Technical Field

[0001] This invention relates to the field of monocrystalline silicon technology, specifically to a method for detecting the bulk resistivity uniformity of lightly phosphorus-doped monocrystalline silicon rods and wafers. Background Technology

[0002] Monocrystalline silicon is a core substrate material for the manufacture of semiconductor devices and high-efficiency photovoltaic cells. Among them, lightly phosphorus-doped N-type monocrystalline silicon is widely used in high-end power devices, integrated circuit substrates, and N-type high-efficiency photovoltaic cells due to its advantages such as moderate resistivity, high minority carrier lifetime, controllable impurity contamination, and stable electrical performance.

[0003] Chinese Patent Publication No. CN112986685B discloses a method and apparatus for measuring the resistivity of a single-crystal silicon rod. The method includes: measuring the resistivity of the silicon wafer at the head of the single-crystal silicon rod; calculating the doping concentration at the head of the single-crystal silicon rod based on the measured resistivity, the single-crystal silicon resistivity, and a first relationship between doping concentration; obtaining a formula for calculating the resistivity of the single-crystal silicon rod, the calculation parameters of which include the concentration ratio at different positions of the single-crystal silicon rod and the doping concentration at the head of the single-crystal silicon rod; and calculating the resistivity at different positions of the single-crystal silicon rod based on the concentration ratio at different positions of the single-crystal silicon rod and the doping concentration at the head of the single-crystal silicon rod.

[0004] The aforementioned patents can only reflect the resistivity changes along the axial direction of the silicon rod in actual use, and cannot capture the resistance fluctuations within the silicon wafer surface. They are prone to missing hidden non-uniform defects, resulting in an incomplete and inaccurate judgment of product quality. Therefore, they do not meet the existing needs. In response, we propose a method for detecting the bulk resistivity uniformity of lightly phosphorus-doped single crystal silicon rods and wafers. Summary of the Invention

[0005] The purpose of this invention is to provide a method for detecting the bulk resistivity uniformity of lightly phosphorus-doped monocrystalline silicon rods and wafers. This method can accurately capture weak bulk resistivity signals under low-concentration doping, further improving detection accuracy. By constructing a three-dimensional distribution model of axial, radial, and bulk resistivity, it can intuitively and comprehensively reflect the bulk resistivity distribution of lightly phosphorus-doped monocrystalline silicon rods and wafers, accurately locate areas with poor uniformity, avoid defect omissions caused by single-dimensional detection, and solve the problem that existing technologies cannot comprehensively evaluate bulk resistivity uniformity. This provides a more comprehensive and accurate basis for product quality judgment. Through the archiving and feedback of detection data, the uniformity judgment results are linked with the production process, enabling timely detection of problems in the production process, reducing the defect rate, and solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a lightly phosphorus-doped single-crystal silicon rod, wherein a cylindrical single-crystal silicon substrate is prepared by the Czochralski method, the substrate having a complete face-centered cubic crystal structure, the surface being pre-polished, and light phosphorus being uniformly doped inside the cylindrical single-crystal silicon substrate by ion implantation to obtain a lightly phosphorus-doped single-crystal silicon rod.

[0007] A method for detecting the bulk resistivity uniformity of a silicon wafer, applied to a lightly phosphorus-doped single-crystal silicon rod, includes the following steps:

[0008] S1: Perform axial multi-point detection on a lightly phosphorus-doped single-crystal silicon rod to obtain axial volume resistivity distribution data;

[0009] S2: Slice the lightly phosphorus-doped single-crystal silicon rod that has completed axial detection;

[0010] S3: Perform radial multi-point detection on the sliced ​​lightly phosphorus-doped monocrystalline silicon wafer to obtain radial volume resistivity distribution data;

[0011] S4: Three-dimensional volume resistivity distribution construction and uniformity determination. Integrate the acquired axial and radial volume resistivity distribution data to construct a three-dimensional volume resistivity distribution model for lightly phosphorus-doped single-crystal silicon rods and wafers. Based on the preset uniformity determination criteria, complete the volume resistivity uniformity determination.

[0012] S5: Data archiving and feedback. All data from the testing process will be archived to form a test report, and the uniformity determination results will be fed back to the production process.

[0013] Preferably, the implementation process of S1 specifically includes:

[0014] The ambient temperature and humidity are calibrated, and the detection area is electromagnetically shielded to block external electromagnetic interference.

[0015] A four-probe tester was used to measure the bulk resistance of a lightly phosphorus-doped single-crystal silicon rod. The potential difference between the probes was detected by a potential difference detector, and the current and potential difference data were collected in real time.

[0016] The volume resistance value of each detection point is calculated based on the current and potential difference data. Each detection point is measured three times, and the average value is taken as the final volume resistance value of that detection point.

[0017] According to the set axial detection point spacing, starting from one end of the lightly phosphorus-doped single crystal silicon rod, the probe assembly is moved sequentially to perform axial multi-point detection on the entire lightly phosphorus-doped single crystal silicon rod until the other end. The position coordinates and corresponding volume resistivity values ​​of each detection point are recorded to form an axial volume resistivity distribution dataset, and the axial volume resistivity distribution curve is plotted.

[0018] Preferably, the implementation process of S2 specifically includes:

[0019] The lightly phosphorus-doped monocrystalline silicon rod that has completed axial volume resistance testing is flattened, and monocrystalline silicon wafers of a predetermined thickness are cut from the head, middle and tail of the lightly phosphorus-doped monocrystalline silicon rod, and marked as wafer H, wafer M and wafer T respectively.

[0020] The cut silicon wafers H, M, and T are sequentially cleaned and dried.

[0021] A four-probe tester was used to measure the bulk resistance of silicon wafers H, M, and T. During the measurement, a concentric ring array method was used to arrange the test points for each silicon wafer.

[0022] Based on the volume resistance values ​​of each measuring point of silicon wafers H, M, and T, the average volume resistance of each silicon wafer is calculated. Then, the volume resistance range and volume resistance variance of the lightly phosphorus-doped monocrystalline silicon rod are calculated. Based on the volume resistance range and volume resistance variance, combined with the preset axial uniformity judgment threshold, the axial volume resistance uniformity level of the lightly phosphorus-doped monocrystalline silicon rod is determined.

[0023] Preferably, the axial uniformity determination threshold is as follows: when the volume resistivity range is ≤0.5Ω·cm and the volume resistivity variance is ≤0.1Ω²·cm², the axial volume resistivity uniformity level of the lightly phosphorus-doped single-crystal silicon rod is Level 1; when 0.5Ω·cm < volume resistivity range ≤1.0Ω·cm and 0.1Ω²·cm² < volume resistivity variance ≤0.2Ω²·cm², the axial volume resistivity uniformity level is Level 2; when the volume resistivity range >1.0Ω·cm or the volume resistivity variance >0.2Ω²·cm², the axial volume resistivity uniformity level is Level 3.

[0024] Preferably, S2 further includes:

[0025] During the slicing process, the volume resistance change of the silicon rod cutting surface is monitored in real time. The monitoring points are the center point and the surrounding symmetrical points of the cutting surface. The monitoring frequency is matched with the slicing speed. Volume resistance data is collected in real time and the volume resistance fluctuation value is recorded.

[0026] If the volume resistance fluctuation value exceeds the preset threshold during the monitoring process, the slicing should be stopped immediately. The cutting parameters of the slicing equipment and the silicon rod fixation status should be checked. Slicing can be continued after the abnormality is eliminated.

[0027] If the fluctuation value continues to exceed the standard, the uniformity of the silicon rod resistance in that area is determined to be unqualified. This area is marked and should be avoided during subsequent slicing to prevent the production of unqualified silicon wafers.

[0028] Preferably, S3 further includes:

[0029] After the detection is completed, the radial volume resistance distribution dataset is preliminarily processed to remove outlier data, and missing data is supplemented using linear interpolation to plot the radial volume resistance distribution curve.

[0030] Radial volume resistance was measured on silicon wafers H, M, and T. The axial position coordinates of each silicon wafer and the volume resistance values ​​of all radial detection points were recorded to form a radial volume resistance distribution dataset.

[0031] Preferably, the implementation process of S4 specifically includes:

[0032] The obtained axial volume resistance distribution dataset is associated with the radial volume resistance distribution dataset. Based on the silicon wafer number and the corresponding axial position coordinates, the radial volume resistance data of the silicon wafer is bound with the volume resistance data of the corresponding axial point of the lightly phosphorus-doped single crystal silicon rod to form a three-dimensional data matrix of axial position, radial position and volume resistance value.

[0033] Based on a three-dimensional data matrix, a three-dimensional distribution model of the bulk resistance of lightly phosphorus-doped single-crystal silicon rods and wafers is constructed.

[0034] Based on the application scenarios of lightly phosphorus-doped monocrystalline silicon, corresponding uniformity judgment criteria are set, and the data in the three-dimensional distribution model of bulk resistance are compared with the preset uniformity judgment criteria.

[0035] If all the judgment criteria are met, the bulk resistivity uniformity of the lightly phosphorus-doped single crystal silicon rod and silicon wafer is deemed qualified.

[0036] If any item is not met, the item is deemed unqualified, the unqualified area is marked, and the reason for the unqualification is analyzed.

[0037] Preferably, the step of setting corresponding uniformity judgment criteria based on the application scenario of lightly phosphorus-doped monocrystalline silicon specifically includes:

[0038] The criterion for determining the uniformity of axial volume resistivity is that the ratio of the volume resistivity difference between any two axial detection points on the same lightly phosphorus-doped single-crystal silicon rod to the average value is ≤ ±3%.

[0039] The criterion for radial volume resistance uniformity is that the ratio of the volume resistance difference between any two radial detection points on the same silicon wafer to the average value is ≤ ±2%.

[0040] The criteria for judging the uniformity of overall volume resistivity are that the ratio of the maximum to the minimum volume resistivity of lightly phosphorus-doped single crystal silicon rods and wafers is ≤1.05, and the volume resistivity distribution curve has no obvious abrupt change.

[0041] Preferably, the implementation process of S5 specifically includes:

[0042] All data from the testing process are organized and archived, and standardized testing reports are generated based on the archived data.

[0043] The test report and uniformity judgment results are promptly fed back to the production process. If the result is deemed qualified, the process can proceed to the next production stage. If the result is deemed unqualified, the production process is optimized based on the reasons for the unqualified result.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] 1. This invention has high detection accuracy and is suitable for low concentration and high uniformity requirements. It adopts a high-sensitivity four-probe tester, which can accurately capture weak volume resistance signals under low concentration doping. At the same time, through strict calibration of the detection environment, fine pretreatment of the sample, and repeated measurement of the detection points, the detection accuracy is further improved.

[0046] 2. By integrating axial and radial detection data, this invention constructs a three-dimensional distribution model of axial, radial, and volume resistivity, which can intuitively and comprehensively reflect the volume resistivity distribution of lightly phosphorus-doped single crystal silicon rods and wafers, accurately locate areas with poor uniformity, avoid defect omissions caused by single-dimensional detection, solve the problem that existing technologies cannot comprehensively evaluate the uniformity of volume resistivity, and provide a more comprehensive and accurate basis for product quality judgment.

[0047] 3. By archiving and providing feedback on the test data, this invention links the uniformity judgment results with the production process, enabling timely detection of problems in the production process, continuously improving the bulk resistivity uniformity of lightly phosphorus-doped monocrystalline silicon rods and wafers, and reducing the defect rate. At the same time, the complete design of the test data archiving facilitates subsequent product quality traceability and data analysis, providing data support for the continuous optimization of the production process, thereby improving the consistency and reliability of lightly phosphorus-doped monocrystalline silicon products. Attached Figure Description

[0048] Figure 1 This is a flowchart of a method for detecting the bulk resistivity uniformity of a silicon wafer according to the present invention.

[0049] Figure 2 This is a flowchart for determining the uniformity of volume resistance according to the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] To address the issue that existing technologies can only reflect resistivity changes along the silicon rod's axial direction, failing to capture resistance fluctuations within the silicon wafer surface and easily overlooking hidden non-uniform defects, resulting in incomplete and inaccurate product quality assessments, please refer to [link to relevant documentation]. Figures 1-2 This embodiment provides the following technical solution:

[0052] A lightly phosphorus-doped single-crystal silicon rod is prepared using the Czochralski method to form a cylindrical single-crystal silicon substrate. The rod exhibits a complete face-centered cubic crystal structure without significant lattice defects, dislocations, or impurity aggregates. The surface undergoes preliminary polishing, resulting in no obvious mechanical damage, oxide layer, or impurity adhesion. Phosphorus doping is uniformly distributed within the lightly phosphorus-doped single-crystal silicon rod, achieved through ion implantation. The doped silicon rod exhibits stable overall electrical properties with no abrupt changes in local doping concentration. Strict control of pulling speed, temperature gradient, and cooling rate during the preparation process ensures uniform overall structure, making it suitable as a stable substrate for slicing and bulk resistivity testing, and adaptable to mass production lines and subsequent non-destructive testing requirements.

[0053] A method for detecting the bulk resistivity uniformity of a silicon wafer, applied to a lightly phosphorus-doped single-crystal silicon rod, includes the following steps:

[0054] S1: Axial volume resistivity uniformity detection of lightly phosphorus-doped single crystal silicon rods. Axial multi-point detection is performed on lightly phosphorus-doped single crystal silicon rods to obtain axial volume resistivity distribution data.

[0055] S2: Slicing of lightly phosphorus-doped monocrystalline silicon rods and synchronous monitoring of the slicing process. The lightly phosphorus-doped monocrystalline silicon rods that have completed axial detection are sliced, and the volume resistance fluctuations during the slicing process are monitored synchronously to ensure that the slicing process does not affect the uniformity of the silicon wafer's volume resistance.

[0056] S3: Radial volume resistance uniformity detection of silicon wafers. Radial multi-point detection is performed on lightly phosphorus-doped monocrystalline silicon wafers after slicing to obtain radial volume resistance distribution data.

[0057] S4: Three-dimensional volume resistivity distribution construction and uniformity determination. Integrate the acquired axial and radial volume resistivity distribution data to construct a three-dimensional volume resistivity distribution model for lightly phosphorus-doped single-crystal silicon rods and wafers. Based on the preset uniformity determination criteria, complete the volume resistivity uniformity determination.

[0058] S5: Data archiving and feedback. All data from the testing process is archived to form a test report, and the uniformity judgment results are fed back to the production process for production process optimization and to achieve closed-loop quality control.

[0059] The implementation process of S1 specifically includes:

[0060] The ambient temperature was controlled at 23℃±5℃ and the relative humidity was controlled at <65%. A temperature and humidity calibrator was used to calibrate the ambient temperature and humidity in real time, with a calibration accuracy of ≤±1℃ (temperature) and ±5% (humidity). At the same time, the detection area was electromagnetically shielded to block external electromagnetic interference and ensure that the electromagnetic interference intensity was ≤0.1μT to avoid electromagnetic signals affecting the detection accuracy.

[0061] A four-probe tester was used to measure the bulk resistance of a lightly phosphorus-doped single-crystal silicon rod. The potential difference between the probes was detected by a potential difference detector, and the current and potential difference data were collected in real time.

[0062] The volume resistance value of each detection point is calculated based on the current and potential difference data. Each detection point is measured three times, and the average value is taken as the final volume resistance value of that detection point.

[0063] According to the set axial detection point spacing, starting from one end of the lightly phosphorus-doped single crystal silicon rod, the probe assembly is moved sequentially to perform axial multi-point detection on the entire lightly phosphorus-doped single crystal silicon rod until the other end. The position coordinates (axial distance) of each detection point and the corresponding volume resistivity value are recorded to form an axial volume resistivity distribution dataset. The axial volume resistivity distribution curve is then plotted to intuitively reflect the changing trend of the axial volume resistivity of the lightly phosphorus-doped single crystal silicon rod.

[0064] The implementation process of S2 specifically includes:

[0065] The lightly phosphorus-doped monocrystalline silicon rod that has completed axial volume resistance testing is flattened to ensure that the end faces are perpendicular to the rod axis. Monocrystalline silicon wafers of a predetermined thickness are cut from the head, middle, and tail of the lightly phosphorus-doped monocrystalline silicon rod and labeled as wafer H (head wafer), wafer M (middle wafer), and wafer T (tail wafer), respectively. The predetermined thickness of the monocrystalline silicon wafer is 200μm to 300μm. The cutting position of the head wafer is 50mm to 100mm from the top of the lightly phosphorus-doped monocrystalline silicon rod, the cutting position of the middle wafer is located at the midpoint of the length of the lightly phosphorus-doped monocrystalline silicon rod, and the cutting position of the tail wafer is 50mm to 100mm from the bottom of the lightly phosphorus-doped monocrystalline silicon rod.

[0066] The cut silicon wafers H, M, and T are sequentially cleaned and dried. The cleaning process is as follows: first, soak them in a 5% hydrofluoric acid solution for 1 to 3 minutes to remove the surface oxide layer; then rinse them with deionized water 3 to 5 times, each rinse lasting 1 to 2 minutes; finally, soak them in a 10% nitric acid solution for 2 to 4 minutes to neutralize any remaining impurities on the surface. The drying process is carried out at a temperature of 25°C to 30°C for 30 to 60 minutes until there is no moisture residue on the surface of the silicon wafers.

[0067] A four-probe tester was used to measure the volume resistance of silicon wafers H, M, and T. Before measurement, the four-probe tester was calibrated using standard resistivity silicon wafers, with a test error ≤ ±1%. During measurement, a concentric ring array method was used for each silicon wafer. Specifically, one central measuring point was set around the center of the silicon wafer, and 3–5 layers of concentric ring measuring points were arranged around the central measuring point. The spacing between adjacent concentric rings was 1 / 10 to 1 / 8 of the silicon wafer diameter. 8–16 measuring points were evenly arranged in each layer of concentric rings, with an angle of 22.5°–45° between adjacent measuring points. The measurement current at each measuring point was 1 mA–5 mA, and the measurement voltage was 10 mV–50 mV. Each measuring point was measured three times, and the average value was taken as the volume resistance value of that measuring point.

[0068] Based on the volume resistance values ​​of each measuring point of silicon wafers H, M, and T, the average volume resistance of each silicon wafer is calculated. Then, the volume resistance range and volume resistance variance of the lightly phosphorus-doped monocrystalline silicon rod are calculated. Based on the volume resistance range and volume resistance variance, combined with the preset axial uniformity judgment threshold, the axial volume resistance uniformity level of the lightly phosphorus-doped monocrystalline silicon rod is determined.

[0069] The specific thresholds for determining axial uniformity are as follows: when the volume resistivity range is ≤0.5Ω·cm and the volume resistivity variance is ≤0.1Ω²·cm², the axial volume resistivity uniformity level of the lightly phosphorus-doped single-crystal silicon rod is Level 1; when 0.5Ω·cm < volume resistivity range ≤1.0Ω·cm and 0.1Ω²·cm² < volume resistivity variance ≤0.2Ω²·cm², the axial volume resistivity uniformity level is Level 2; when the volume resistivity range >1.0Ω·cm or the volume resistivity variance >0.2Ω²·cm², the axial volume resistivity uniformity level is Level 3.

[0070] S2 also includes:

[0071] During the slicing process, the volume resistance change of the silicon rod cutting surface is monitored in real time. The monitoring points are the center point and the surrounding symmetrical points of the cutting surface. The monitoring frequency is matched with the slicing speed. Volume resistance data is collected in real time and the volume resistance fluctuation value is recorded.

[0072] If the volume resistance fluctuation value exceeds the preset threshold (±0.5%) during the monitoring process, immediately stop slicing, check the cutting parameters of the slicing equipment (cutting speed, cutting pressure, cutting fluid state) and the silicon rod fixing status, and continue slicing after eliminating the abnormality;

[0073] If the fluctuation value continues to exceed the standard, the uniformity of the silicon rod resistance in that area is determined to be unqualified. This area is marked and should be avoided during subsequent slicing to prevent the production of unqualified silicon wafers.

[0074] S3 also includes:

[0075] After the test is completed, the radial volume resistance distribution dataset is preliminarily processed to remove outlier data (data with deviations exceeding the average value by more than 5%), and missing data is supplemented using linear interpolation. The radial volume resistance distribution curve is then plotted to visually reflect the changing trend of the volume resistance within the silicon wafer.

[0076] Radial volume resistance is measured on silicon wafers H, M, and T. The axial position coordinates of each silicon wafer and the volume resistance values ​​of all radial detection points are recorded to form a radial volume resistance distribution dataset, ensuring that the dataset corresponds one-to-one with the axial volume resistance distribution dataset.

[0077] The implementation process of S4 specifically includes:

[0078] The obtained axial volume resistance distribution dataset is associated with the radial volume resistance distribution dataset. Based on the silicon wafer number and the corresponding axial position coordinates, the radial volume resistance data of the silicon wafer is bound with the volume resistance data of the corresponding axial point of the lightly phosphorus-doped single crystal silicon rod to form a three-dimensional data matrix of axial position, radial position and volume resistance value.

[0079] Based on a three-dimensional data matrix, a three-dimensional distribution model of bulk resistivity of lightly phosphorus-doped monocrystalline silicon rods and wafers is constructed. The three-dimensional distribution model of bulk resistivity can be used to intuitively display the distribution of bulk resistivity in the axial direction of the lightly phosphorus-doped monocrystalline silicon rod and the radial direction of the wafer. It can realize the query of bulk resistivity value at any point and the analysis of distribution trend. At the same time, it can mark the maximum value, minimum value and areas with poor distribution uniformity of bulk resistivity.

[0080] Based on the application scenarios of lightly phosphorus-doped monocrystalline silicon, corresponding uniformity judgment criteria are set, and the data in the three-dimensional distribution model of bulk resistance are compared with the preset uniformity judgment criteria.

[0081] If all the judgment criteria are met, the bulk resistivity uniformity of the lightly phosphorus-doped single crystal silicon rod and silicon wafer is deemed qualified.

[0082] If any one of the requirements is not met, the product is deemed unqualified, and the unqualified area (axial position, radial position) is marked. The reasons for the unqualification are analyzed (such as uneven doping, abnormal slicing process, interference from the testing environment, etc.).

[0083] Based on the application scenarios of lightly phosphorus-doped monocrystalline silicon, corresponding uniformity judgment criteria are set, specifically including:

[0084] The criterion for determining the uniformity of axial volume resistivity is that the ratio of the volume resistivity difference between any two axial detection points on the same lightly phosphorus-doped single-crystal silicon rod to the average value is ≤ ±3%.

[0085] The criterion for radial volume resistance uniformity is that the ratio of the volume resistance difference between any two radial detection points on the same silicon wafer to the average value is ≤ ±2%.

[0086] The overall bulk resistance uniformity determination criterion is that the ratio of the maximum value to the minimum value of the bulk resistance of lightly doped phosphorus single crystal rods and wafers ≤ 1.05, and there is no obvious mutation in the bulk resistance distribution curve (mutation amplitude ≤ ±5%).

[0087] The implementation process of S5 specifically includes:

[0088] Sort and file all data during the detection process, including detection environment parameters, detection equipment debugging parameters, sample information (doping concentration, size, serial number, etc.), axial bulk resistance distribution data, radial bulk resistance distribution data, slice process monitoring data, bulk resistance three-dimensional distribution model data, uniformity determination results, etc. Generate a standardized detection report based on the archived data. The report includes sample basic information, detection environment, detection equipment, detection process, detection data, bulk resistance three-dimensional distribution charts, uniformity determination results, analysis of unqualified areas (if any), etc.;

[0089] Timely feedback the detection report and uniformity determination results to the production link. If the determination is qualified, it can normally enter the next production link; if the determination is unqualified, optimize the production process for the unqualified reasons: for example, if the unqualified is caused by uneven doping, adjust parameters such as the doping agent addition speed and pulling speed during the crystal pulling process; if the unqualified is caused by abnormal slicing process, adjust parameters such as slicing speed, cutting fluid temperature, clamping force, etc.; at the same time, process the unqualified samples (such as rework, scrapping) to prevent unqualified products from flowing into the downstream link.

[0090] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprises", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0091] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made in these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A lightly doped monocrystalline silicon rod, characterized in that, The cylindrical single-crystal silicon substrate is prepared by the Czochralski method. Its crystal structure is a complete face-centered cubic structure. The surface is initially polished. Light phosphorus is uniformly doped inside the cylindrical single-crystal silicon substrate by ion implantation to obtain a lightly phosphorus-doped single-crystal silicon rod.

2. A method for detecting bulk resistance uniformity of a silicon wafer, applied to the lightly doped phosphorus single crystal silicon rod of claim 1, characterized in that, Includes the following steps: S1: Perform axial multi-point detection on a lightly phosphorus-doped single-crystal silicon rod to obtain axial volume resistivity distribution data; S2: Slice the lightly phosphorus-doped single-crystal silicon rod that has completed axial detection; S3: Perform radial multi-point detection on the sliced ​​lightly phosphorus-doped monocrystalline silicon wafer to obtain radial volume resistivity distribution data; S4: Integrate the acquired axial and radial volume resistivity distribution data to construct a three-dimensional volume resistivity distribution model of lightly phosphorus-doped single-crystal silicon rods and wafers, and complete the volume resistivity uniformity determination based on the preset uniformity judgment criteria. S5: Archive all data from the testing process, generate a test report, and feed the uniformity determination results back to the production process.

3. The method for detecting the bulk resistivity uniformity of a silicon wafer according to claim 2, characterized in that, The implementation process of S1 specifically includes: The ambient temperature and humidity are calibrated, and the detection area is electromagnetically shielded to block external electromagnetic interference. A four-probe tester was used to measure the bulk resistance of a lightly phosphorus-doped single-crystal silicon rod. The potential difference between the probes was detected by a potential difference detector, and the current and potential difference data were collected in real time. The volume resistance value of each detection point is calculated based on the current and potential difference data. Each detection point is measured three times, and the average value is taken as the final volume resistance value of that detection point. According to the set axial detection point spacing, starting from one end of the lightly phosphorus-doped single crystal silicon rod, the probe assembly is moved sequentially to perform axial multi-point detection on the entire lightly phosphorus-doped single crystal silicon rod until the other end. The position coordinates and corresponding volume resistivity values ​​of each detection point are recorded to form an axial volume resistivity distribution dataset, and the axial volume resistivity distribution curve is plotted.

4. The method of claim 2, wherein the step of detecting the bulk resistance uniformity of the silicon wafer is performed by a method comprising the steps of: The implementation process of S2 specifically includes: ​ The lightly phosphorus-doped monocrystalline silicon rod that has completed axial volume resistance testing is flattened, and monocrystalline silicon wafers of a predetermined thickness are cut from the head, middle and tail of the lightly phosphorus-doped monocrystalline silicon rod, and marked as wafer H, wafer M and wafer T respectively. The cut silicon wafers H, M, and T are sequentially cleaned and dried. A four-probe tester was used to measure the bulk resistance of silicon wafers H, M, and T. During the measurement, a concentric ring array method was used to arrange the test points for each silicon wafer. Based on the volume resistance values ​​of each measuring point of silicon wafers H, M, and T, the average volume resistance of each silicon wafer is calculated. Then, the volume resistance range and volume resistance variance of the lightly phosphorus-doped monocrystalline silicon rod are calculated. Based on the volume resistance range and volume resistance variance, combined with the preset axial uniformity judgment threshold, the axial volume resistance uniformity level of the lightly phosphorus-doped monocrystalline silicon rod is determined.

5. The method for detecting the bulk resistivity uniformity of a silicon wafer according to claim 4, characterized in that, The specific thresholds for determining axial uniformity are as follows: when the volume resistivity range is ≤0.5Ω·cm and the volume resistivity variance is ≤0.1Ω²·cm², the axial volume resistivity uniformity level of the lightly phosphorus-doped single-crystal silicon rod is Level 1; when 0.5Ω·cm < volume resistivity range ≤1.0Ω·cm and 0.1Ω²·cm² < volume resistivity variance ≤0.2Ω²·cm², the axial volume resistivity uniformity level is Level 2; when the volume resistivity range >1.0Ω·cm or the volume resistivity variance >0.2Ω²·cm², the axial volume resistivity uniformity level is Level 3.

6. The method for detecting the bulk resistivity uniformity of a silicon wafer according to claim 4, characterized in that, S2 further includes: During the slicing process, the volume resistance change of the silicon rod cutting surface is monitored in real time. The monitoring points are the center point and the surrounding symmetrical points of the cutting surface. The monitoring frequency is matched with the slicing speed. Volume resistance data is collected in real time and the volume resistance fluctuation value is recorded. If the volume resistance fluctuation value exceeds the preset threshold during the monitoring process, the slicing should be stopped immediately. The cutting parameters of the slicing equipment and the silicon rod fixation status should be checked. Slicing can be continued after the abnormality is eliminated. If the fluctuation value continues to exceed the standard, the uniformity of the silicon rod resistance in that area is determined to be unqualified. This area is marked and should be avoided during subsequent slicing to prevent the production of unqualified silicon wafers.

7. The method for detecting the bulk resistivity uniformity of a silicon wafer according to claim 4, characterized in that, S3 further includes: After the detection is completed, the radial volume resistance distribution dataset is preliminarily processed to remove outlier data, and missing data is supplemented using linear interpolation to plot the radial volume resistance distribution curve. Radial volume resistance was measured on silicon wafers H, M, and T. The axial position coordinates of each silicon wafer and the volume resistance values ​​of all radial detection points were recorded to form a radial volume resistance distribution dataset.

8. The method for detecting the bulk resistivity uniformity of a silicon wafer according to claim 2, characterized in that, The implementation process of S4 specifically includes: The obtained axial volume resistance distribution dataset is associated with the radial volume resistance distribution dataset. Based on the silicon wafer number and the corresponding axial position coordinates, the radial volume resistance data of the silicon wafer is bound with the volume resistance data of the corresponding axial point of the lightly phosphorus-doped single crystal silicon rod to form a three-dimensional data matrix of axial position, radial position and volume resistance value. Based on a three-dimensional data matrix, a three-dimensional distribution model of the bulk resistivity of lightly phosphorus-doped single-crystal silicon rods and wafers was constructed. Based on the application scenarios of lightly phosphorus-doped monocrystalline silicon, corresponding uniformity judgment criteria are set, and the data in the three-dimensional distribution model of bulk resistance are compared with the preset uniformity judgment criteria. If all the judgment criteria are met, the bulk resistivity uniformity of the lightly phosphorus-doped single crystal silicon rod and silicon wafer is deemed qualified. If any item is not met, the item is deemed unqualified, the unqualified area is marked, and the reason for the unqualification is analyzed.

9. The method for detecting the bulk resistivity uniformity of a silicon wafer according to claim 8, characterized in that, The uniformity judgment criteria set according to the application scenarios of lightly phosphorus-doped monocrystalline silicon specifically include: The criterion for determining the uniformity of axial volume resistivity is that the ratio of the volume resistivity difference between any two axial detection points on the same lightly phosphorus-doped single-crystal silicon rod to the average value is ≤ ±3%. The criterion for radial volume resistance uniformity is that the ratio of the volume resistance difference between any two radial detection points on the same silicon wafer to the average value is ≤ ±2%. The criteria for judging the uniformity of overall volume resistivity are that the ratio of the maximum to the minimum volume resistivity of lightly phosphorus-doped single crystal silicon rods and wafers is ≤1.05, and the volume resistivity distribution curve has no obvious abrupt change.

10. The method for detecting the bulk resistivity uniformity of a silicon wafer according to claim 2, characterized in that, The implementation process of S5 specifically includes: All data from the testing process are organized and archived, and standardized testing reports are generated based on the archived data. The test report and uniformity judgment results are promptly fed back to the production process. If the result is deemed qualified, the process can proceed to the next production stage. If the result is deemed unqualified, the production process is optimized based on the reasons for the unqualified result.

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