Silicon wafer resistivity test method and device
By using laser heating to decompose oxygen clusters in silicon wafers into interstitial oxygen, the problem of distorted resistivity test data in the Czochralski single-crystal silicon production process is solved, enabling more accurate and efficient resistivity measurement, simplifying the process and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-07
- Publication Date
- 2026-03-31
AI Technical Summary
During the production of Czochralski monocrystalline silicon, the oxygen donor effect causes distortion in the resistivity test data of silicon wafers, affecting the accuracy of the test, especially for N-type BC solar cells.
A laser beam is used to heat the surface of a silicon wafer to a target temperature and maintain it for a preset time to decompose oxygen clusters into interstitial oxygen. The wafer is then rapidly cooled and its resistivity is measured. The concentrated and rapid nature of the laser heat source is used to prevent the oxygen clusters from re-aggregating.
It improves the accuracy of silicon wafer resistivity testing, saves time and reduces costs, simplifies the process, and avoids the test distortion problems caused by the long-term high-temperature stay in the traditional annealing furnace method.
Smart Images
Figure CN121762931A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of silicon wafer testing technology, and in particular to a method and apparatus for testing the resistivity of silicon wafers. Background Technology
[0002] In the production process of Czochralski-grown single-crystal silicon, the silicon needs to be melted in a quartz crucible at a high temperature of 1417℃. The molten silicon reacts with the SiO2 in the quartz crucible to generate volatile SiO. Simultaneously, some oxygen atoms dissolve into the interstitial spaces of the silicon lattice, forming interstitial oxygen (O2). i When single-crystal silicon containing interstitial oxygen is placed in a medium-low temperature environment of 300-500℃, the interstitial oxygen atoms will migrate and aggregate to form oxygen clusters (SiO4) with donor characteristics. 2- These oxygen clusters release free electrons, causing changes in the concentration and type of charge carriers inside the silicon wafer.
[0003] For P-type silicon wafers, free electrons lead to an increase in resistivity; for N-type silicon wafers, free electrons lead to a significant decrease in resistivity. Especially for N-type BC (back contact) solar cells, due to the low-doping process, their initial resistivity is high. Since the degree of resistivity disturbance caused by the oxygen donor effect is positively correlated with the initial resistivity of the silicon wafer, this cell is particularly affected by the oxygen donor effect. When the silicon wafer resistivity exceeds 30 Ω·cm, the resistivity fluctuations caused by oxygen clusters will lead to significant distortion in electrical performance test data, failing to reflect the true electrical characteristics of the silicon wafer.
[0004] Therefore, in related technologies, the oxygen donor effect in the production process of Czochralski single crystal silicon can cause distortion of the electrical performance test data of silicon wafers, affecting the accuracy of the test. Summary of the Invention
[0005] Therefore, it is necessary to provide a silicon wafer resistivity testing method and apparatus that can improve the accuracy of silicon wafer test data in response to the above-mentioned technical problems.
[0006] In a first aspect, this application provides a method for testing the resistivity of a silicon wafer, comprising:
[0007] The laser beam is controlled to heat the surface area of the silicon wafer under test, so that the surface temperature of the silicon wafer under test reaches the target temperature and the heating continues for a preset time after the target temperature is reached, so that the oxygen clusters formed in the silicon wafer under test are decomposed into interstitial oxygen.
[0008] Control the laser beam to leave the surface area of the silicon wafer under test;
[0009] The resistivity of the silicon wafer under test is measured after the wafer has been cooled.
[0010] In one embodiment, before controlling the laser beam to heat the surface area of the silicon wafer under test, the method further includes:
[0011] The silicon wafer to be tested is cleaned to remove surface oil and the cutting damage layer formed during the cutting process.
[0012] In one embodiment, controlling the laser beam to heat the surface area of the silicon wafer under test includes:
[0013] The laser beam is controlled to scan the surface area of the silicon wafer under test in a continuous heating trajectory to heat the surface of the silicon wafer under test.
[0014] In one embodiment, the method further includes:
[0015] After reaching the target temperature, the laser beam is controlled to continuously scan the surface area of the silicon wafer under test along the heating trajectory for the preset duration, so that the oxygen clusters formed in the silicon wafer under test are decomposed into interstitial oxygen.
[0016] In one embodiment, the method further includes:
[0017] The surface temperature of the silicon wafer under test is monitored using a temperature sensor.
[0018] When the surface temperature of the silicon wafer under test reaches the target temperature, the current laser power is determined;
[0019] Keeping the current laser power constant, the laser beam continues to heat the silicon wafer under test for a preset time.
[0020] In one embodiment, before measuring the resistivity of the silicon wafer under test after it has been cooled, the method further includes:
[0021] The surface temperature of the silicon wafer under test is monitored using a temperature sensor.
[0022] When the surface temperature of the silicon wafer under test reaches room temperature, it is determined that the silicon wafer under test has completed cooling.
[0023] In one embodiment, after measuring the resistivity of the silicon wafer under test after it has been cooled, the method further includes:
[0024] The theoretical resistivity of the silicon wafer under test is determined based on the doping amount of the silicon wafer under test.
[0025] The measured resistivity is compared with the theoretical resistivity, and the accuracy of the test is determined based on the comparison results.
[0026] In one embodiment, measuring the resistivity of the silicon wafer under test after it has been cooled includes:
[0027] The resistivity of the silicon wafer under test was measured using the four-probe method.
[0028] In one embodiment, the silicon wafer to be tested is a silicon wafer with a doping amount less than a threshold.
[0029] Secondly, this application also provides a silicon wafer resistivity testing device, comprising:
[0030] The laser heating module is used to emit a laser beam to heat the surface area of the silicon wafer to be tested.
[0031] The heating control module is used to control the laser beam to perform heating operations, so that the surface temperature of the silicon wafer under test reaches the target temperature and continues to heat for a preset time after reaching the target temperature, so that the oxygen clusters formed in the silicon wafer under test decompose into interstitial oxygen, and after the heating is completed, control the laser beam to leave the surface area of the silicon wafer under test.
[0032] A resistivity testing module is used to measure the resistivity of the silicon wafer under test after it has been cooled.
[0033] The aforementioned silicon wafer resistivity testing method and apparatus control a laser beam to heat the surface area of the silicon wafer under test, raising its surface temperature to a target temperature and maintaining it at that temperature for a preset time. This causes oxygen clusters formed within the silicon wafer to decompose into interstitial oxygen. Afterward, the laser beam is controlled to leave the surface area of the silicon wafer, and the resistivity is measured once the wafer has cooled completely. This method utilizes the concentrated and rapid heating characteristics of a laser heat source. The laser quickly heats the silicon wafer to the target temperature, causing the oxygen clusters to decompose. Upon cessation of heating, the heat source disappears instantly, allowing the silicon wafer to cool rapidly without external force. This avoids prolonged exposure to the 300-500°C range, which could lead to the re-aggregation of interstitial oxygen and the formation of new oxygen clusters. This improves the accuracy of silicon wafer resistivity testing and saves significant time compared to traditional annealing furnaces, increasing testing efficiency. Furthermore, the process is simple and cost-effective. Attached Figure Description
[0034] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0035] Figure 1 This is a flowchart illustrating a silicon wafer resistivity testing method in one embodiment;
[0036] Figure 2 This is a schematic flowchart of the silicon wafer heating step in one embodiment;
[0037] Figure 3 This is a flowchart illustrating a silicon wafer resistivity testing method in another embodiment;
[0038] Figure 4 This is a structural block diagram of a silicon wafer resistivity testing device in one embodiment. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0040] In one exemplary embodiment, such as Figure 1 As shown, a method for testing the resistivity of a silicon wafer is provided, including the following steps S110 to S130. Wherein:
[0041] Step S110: Control the laser beam to heat the surface area of the silicon wafer under test, so that the surface temperature of the silicon wafer under test reaches the target temperature, and continue heating for a preset time after reaching the target temperature, so that the oxygen clusters formed in the silicon wafer under test are decomposed into interstitial oxygen.
[0042] In some embodiments, the silicon wafer to be tested can be a silicon wafer with a doping amount less than a threshold, i.e., with a high oxygen content, such as Czochralski silicon.
[0043] The target temperature is the temperature at which oxygen clusters formed within the silicon wafer are fully decomposed into interstitial oxygen. In some embodiments, the target temperature is at least 550°C, but it should not be too high to avoid burning through the silicon wafer.
[0044] Oxygen clusters refer to aggregates of oxygen atoms formed by the migration and aggregation of multiple interstitial oxygen atoms under thermally activated conditions (such as high-temperature annealing and device manufacturing processes). Interstitial oxygen refers to oxygen atoms existing as single atoms in the interstitial positions of the silicon crystal lattice. By heating oxygen clusters to decompose them into interstitial oxygen, they no longer provide electrons, thus avoiding any impact on the resistivity of the silicon wafer.
[0045] For example, the laser beam is controlled to uniformly heat the surface area of the silicon wafer under test to ensure that the temperature of each area on the surface of the silicon wafer is consistent. After the surface area of the silicon wafer under test reaches the target temperature through heating, the laser beam can continue to be controlled to uniformly scan the surface of the silicon wafer under test, so that the silicon wafer under test can be maintained at a temperature of at least the target temperature for a preset time. This allows the oxygen clusters formed in the silicon wafer under test to be fully decomposed into interstitial oxygen, so as to avoid the influence of incomplete decomposition on the subsequent test results and ensure the accuracy of subsequent resistivity tests.
[0046] In some embodiments, the laser beam spot size should be reasonable; that is, the spot size should not be too small to avoid ablation of the silicon wafer surface, nor too large to avoid affecting the heating effect.
[0047] Step S120: Control the laser beam to leave the surface area of the silicon wafer to be tested.
[0048] For example, after heating the silicon wafer under test to the target temperature and continuing heating for a preset time, it is confirmed that the oxygen clusters within the silicon wafer under test are fully decomposed into interstitial oxygen, so that the silicon wafer under test reaches a state where it is unaffected by the free electrons released from the oxygen clusters. Further, the laser can be turned off to stop heating, and the laser beam can be controlled to leave the surface area of the silicon wafer under test, thereby enabling rapid cooling of the silicon wafer under test.
[0049] It is understandable that, due to the concentrated heat source of laser heating, the surface of the silicon wafer under test can cool rapidly after heating stops, skipping the temperature range of 300℃-500℃, thereby avoiding the secondary generation of oxygen clusters.
[0050] Step S130: After the silicon wafer under test has been cooled, measure the resistivity of the silicon wafer under test.
[0051] For example, after the silicon wafer under test has cooled down, a resistivity test can be performed to measure the resistivity of the silicon wafer under test.
[0052] In the aforementioned silicon wafer resistivity testing method, a laser beam is controlled to heat the surface area of the silicon wafer under test, raising its surface temperature to a target temperature and maintaining it at that temperature for a preset time. This causes oxygen clusters formed within the silicon wafer to decompose into interstitial oxygen. Afterward, the laser beam is controlled to leave the surface area of the silicon wafer, and the resistivity is measured once the wafer has cooled completely. This method utilizes the concentrated and rapid heating characteristics of a laser heat source. The laser quickly heats the silicon wafer to the target temperature, causing the oxygen clusters to decompose. Upon cessation of heating, the heat source disappears instantly, allowing the silicon wafer to cool rapidly without external force. This avoids prolonged exposure to the 300-500°C range, which could lead to the re-aggregation of interstitial oxygen and the formation of new oxygen clusters. This improves the accuracy of silicon wafer resistivity testing and, compared to traditional annealing furnaces, saves significant time, increases testing efficiency, and is simpler and less expensive.
[0053] In an exemplary embodiment, before controlling the laser beam to heat the surface area of the silicon wafer to be tested in step S110, the method further includes cleaning the silicon wafer to be tested to remove surface oil and cutting damage layers formed during the cutting process.
[0054] It is understandable that during the silicon wafer manufacturing process, some oil stains will be generated on its surface. These oil stains can cover the silicon wafer surface, hindering the transport of charge carriers during electrical testing, or forming an insulating layer that interferes with the test. Similarly, cutting can easily form a cutting damage layer on the silicon wafer surface. This cutting damage layer contains a large number of defects such as dislocations and vacancies, and its conductivity mechanism is completely different from that of the silicon wafer itself (defect-induced impurity conductivity is the main factor). If it is not removed, the test results will deviate significantly from the true doping characteristics of the silicon wafer. Therefore, in this embodiment, after obtaining the incoming silicon wafer (i.e., the silicon wafer to be tested), the silicon wafer to be tested is cleaned before being tested to remove the surface oil stains and the cutting damage layer formed during the cutting process.
[0055] For example, a tank cleaning method can be used to clean the silicon wafer to be tested. For instance, the pretreatment of the silicon wafer to be tested can be achieved by first removing oil stains, then removing the cutting damage layer, then rinsing off the residue, and finally drying.
[0056] In this embodiment, by cleaning the silicon wafer to be tested, the surface oil stains of the silicon wafer to be tested can be removed, the cutting damage layer formed during the cutting process can be eliminated, and its original surface state can be restored, thereby ensuring the accuracy of the resistivity test results of the silicon wafer to be tested.
[0057] In an exemplary embodiment, step S110, controlling the laser beam to heat the surface area of the silicon wafer under test, includes: controlling the laser beam to scan the surface area of the silicon wafer under test with a continuous heating trajectory to heat the surface of the silicon wafer under test.
[0058] For example, after cleaning the silicon wafer to be tested to remove surface oil and cut damage layers, it is placed under a laser to heat the wafer. For instance, a galvanometer system can control the laser beam to scan the surface area of the wafer at high speed, forming a continuous heating trajectory to avoid localized overheating. The galvanometer system is an optical scanning system including a scanning motor, a reflector, a position sensor, a control card / driver, and a lens. The scanning motor generates a precise deflection angle through an input control current; the reflector is mounted on the rotor of the scanning motor to reflect the laser beam; the position sensor is used to detect the actual position (angle) of the reflector in real time; and the control card / driver is used to drive the motor movement.
[0059] In some embodiments, the surface temperature of the silicon wafer under test can be adjusted to reach the target temperature, i.e., above 550°C, by adjusting the laser power. The laser power should not be too high to avoid burning through the silicon wafer.
[0060] In this embodiment, the laser beam is controlled to scan the surface area of the silicon wafer under test with a continuous heating trajectory to heat the surface of the silicon wafer under test, which can ensure the uniformity of heating of the silicon wafer under test and avoid local overheating.
[0061] In an exemplary embodiment, the method further includes: after the surface temperature of the silicon wafer under test reaches the target temperature, controlling the laser beam to continuously scan the surface area of the silicon wafer under test along the heating trajectory for a preset duration, so that the oxygen clusters formed in the silicon wafer under test are decomposed into interstitial oxygen.
[0062] For example, in order to fully decompose the oxygen clusters formed in the silicon wafer under test into interstitial oxygen, the silicon wafer under test is heated after the surface temperature of the silicon wafer under test reaches the target temperature. For example, the surface area of the silicon wafer under test can be continuously scanned along the heating trajectory for a preset time, such as the time for 3-5 scans.
[0063] In this embodiment, after the surface temperature of the silicon wafer under test reaches the target temperature, the surface area of the silicon wafer under test continues to be heated for a preset duration to ensure that the oxygen clusters formed in the silicon wafer under test can be fully decomposed.
[0064] In one exemplary embodiment, such as Figure 2 As shown, the method further includes:
[0065] Step S210: Monitor the surface temperature of the silicon wafer under test using a temperature sensor;
[0066] Step S220: When the surface temperature of the silicon wafer under test is monitored to reach the target temperature, determine the current laser power;
[0067] Step S230: Keep the current laser power unchanged and control the laser beam to continue heating the silicon wafer under test for a preset time.
[0068] For example, the surface temperature of the silicon wafer under test can be monitored using a temperature sensor to determine whether the surface temperature of the silicon wafer under test has reached the target temperature. When the surface temperature of the silicon wafer under test reaches the target temperature, considering that the decomposition of oxygen clusters formed within the silicon wafer under test is not an instantaneous process, it is also necessary to maintain the silicon wafer under test at a temperature not lower than the target temperature for a certain period of time to ensure the sufficient decomposition of oxygen clusters. The laser temperature is changed by adjusting the laser power; therefore, when it is determined that the surface temperature of the silicon wafer under test has reached the target temperature, the laser power used at this time can be determined. Maintaining this laser power, the surface area of the silicon wafer under test continues to be heated for a preset time to ensure that the oxygen clusters formed within the silicon wafer under test can be fully decomposed.
[0069] In this embodiment, a temperature sensor monitors the surface temperature of the silicon wafer under test to determine whether it has reached the target temperature. This judgment, based on a measurable temperature, ensures the reliability of the result. Furthermore, after determining that the silicon wafer has reached the target temperature, the laser beam is controlled to continue heating the silicon wafer at the laser power required to reach the target temperature. This ensures that the silicon wafer remains at or above the target temperature, facilitating the decomposition of oxygen clusters.
[0070] In an exemplary embodiment, before measuring the resistivity of the silicon wafer under test after it has been cooled, the method further includes: monitoring the surface temperature of the silicon wafer under test using a temperature sensor; and determining that the silicon wafer under test has been cooled when the surface temperature of the silicon wafer under test reaches room temperature.
[0071] For example, the surface temperature of the silicon wafer under test can be monitored using a temperature sensor to determine whether the silicon wafer has finished cooling. Specifically, when the surface temperature measured by the temperature sensor reaches room temperature, i.e., indoor temperature, it is determined that the silicon wafer under test has finished cooling, and resistivity can be measured.
[0072] In this embodiment, the surface temperature of the silicon wafer under test is monitored by a temperature sensor to determine whether the silicon wafer under test has been cooled completely. This judgment, which uses a temperature that can be actually measured, can ensure the reliability of the judgment result.
[0073] In an exemplary embodiment, after measuring the resistivity of the silicon wafer under test after it has been cooled, the method further includes: determining the theoretical resistivity of the silicon wafer under test based on the doping amount; comparing the measured resistivity with the theoretical resistivity; and determining the test accuracy based on the comparison result.
[0074] It is understandable that the doping level of a silicon wafer is negatively correlated with its oxygen content; lower doping levels result in higher oxygen content, and vice versa. The doping level is also negatively correlated with the resistivity of the silicon wafer; generally, lower doping levels lead to higher theoretical resistivity, and vice versa. Therefore, this relationship can be used to calculate the theoretical resistivity of the silicon wafer under test based on its doping level. Furthermore, the calculated theoretical resistivity is compared with the actually measured resistivity to determine the accuracy of the test results.
[0075] Table 1 below shows a comparison of the theoretical resistivity, the resistivity measured without this method, and the resistivity measured using this method for the three groups of silicon wafers obtained through experiments. As can be seen from Table 1, the resistivity measured without this method differs significantly from the theoretical resistivity, while the resistivity measured using the laser heating and cooling method of this application is significantly closer to the theoretical resistivity. This verifies the effectiveness of this method.
[0076] Table 1 Resistivity Comparison Results
[0077]
[0078] In this embodiment, the theoretical resistivity of the silicon wafer under test is determined based on the doping amount of the silicon wafer under test. The accuracy of the test method of this application can be verified by comparing the measured resistivity with the theoretical resistivity.
[0079] In one exemplary embodiment, measuring the resistivity of the silicon wafer under test after it has been cooled includes measuring the resistivity of the silicon wafer under test using a four-probe method.
[0080] For example, a linear four-probe array (four probes arranged at equal intervals) is used to make vertical contact with the silicon wafer surface. Then, current is applied to the four probes, the voltage drop is measured, and the resistivity of the silicon wafer under test is calculated based on the voltage drop, current, etc.
[0081] In this embodiment, the resistivity of the silicon wafer under test is measured by the four-probe method, which can eliminate the influence of contact resistance and ensure the reliability of the measurement results.
[0082] refer to Figure 3 The diagram below illustrates a process flow chart for a silicon wafer resistivity testing method according to another embodiment. In this embodiment, the method includes the following steps:
[0083] Step S310: Clean the silicon wafer to be tested to remove surface oil and the cutting damage layer formed during the cutting process.
[0084] Step S320: Control the laser beam to scan the surface area of the silicon wafer to be tested with a continuous heating trajectory in order to heat the surface of the silicon wafer to be tested;
[0085] Step S330: Monitor the surface temperature of the silicon wafer under test using a temperature sensor. When the surface temperature of the silicon wafer under test reaches the target temperature, determine the current laser power.
[0086] Step S340: Keep the current laser power unchanged and control the laser beam to continue heating the silicon wafer under test for a preset time so that the oxygen clusters formed in the silicon wafer under test are decomposed into interstitial oxygen.
[0087] Step S350: Control the laser beam to leave the surface area of the silicon wafer to be tested;
[0088] Step S360: When the surface temperature of the silicon wafer under test reaches room temperature, it is determined that the silicon wafer under test has been cooled, and the resistivity of the silicon wafer under test is measured by the four-probe method.
[0089] This method utilizes the concentrated and rapid heating characteristics of laser heat sources to quickly heat silicon wafers to the target temperature, causing oxygen clusters to decompose. After heating stops, the heat source disappears instantly, and the silicon wafer can be rapidly cooled without external force. This avoids prolonged exposure to the 300-500℃ range, which can lead to the re-aggregation of interstitial oxygen and the formation of oxygen clusters. This improves the distortion problem in silicon wafer resistivity testing. Compared with traditional annealing furnaces, this method saves a significant amount of time, improves testing efficiency, and has a simpler process and lower cost.
[0090] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.
[0091] Based on the same inventive concept, this application also provides a silicon wafer resistivity testing device for implementing the silicon wafer resistivity testing method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the silicon wafer resistivity testing device provided below can be found in the limitations of the silicon wafer resistivity testing method described above, and will not be repeated here.
[0092] In one exemplary embodiment, such as Figure 4 As shown, a silicon wafer resistivity testing device is provided, comprising:
[0093] The laser heating module 410 is used to emit a laser beam to heat the surface area of the silicon wafer to be tested;
[0094] The heating control module 420 is used to control the laser beam to perform heating operations, so that the surface temperature of the silicon wafer under test reaches the target temperature and continues to heat for a preset time after reaching the target temperature, so that the oxygen clusters formed in the silicon wafer under test decompose into interstitial oxygen, and after the heating is completed, control the laser beam to leave the surface area of the silicon wafer under test.
[0095] The resistivity test module 430 is used to measure the resistivity of the silicon wafer under test after it has been cooled.
[0096] In one embodiment, the heating control module 420 is used to clean the silicon wafer to be tested in order to remove surface oil and cutting damage layers formed during the cutting process.
[0097] In one embodiment, the heating control module 420 is used to control the laser beam to scan the surface area of the silicon wafer under test with a continuous heating trajectory in order to heat the surface of the silicon wafer under test.
[0098] In one embodiment, the heating control module 420 is used to control the laser beam to continuously scan the surface area of the silicon wafer under test along the heating trajectory after the target temperature is reached, for a preset duration, so that the oxygen clusters formed in the silicon wafer under test are decomposed into interstitial oxygen.
[0099] In one embodiment, the heating control module 420 is used to monitor the surface temperature of the silicon wafer under test through a temperature sensor; when the surface temperature of the silicon wafer under test reaches the target temperature, the current laser power is determined; the current laser power is kept unchanged, and the laser beam is controlled to continue heating the silicon wafer under test for a preset time.
[0100] In one embodiment, the device further includes a monitoring module for monitoring the surface temperature of the silicon wafer under test via a temperature sensor; when the surface temperature of the silicon wafer under test reaches room temperature, it is determined that the silicon wafer under test has completed cooling.
[0101] In one embodiment, the apparatus further includes a verification module for determining the theoretical resistivity of the silicon wafer under test based on the doping amount of the silicon wafer under test; comparing the measured resistivity with the theoretical resistivity; and determining the test accuracy based on the comparison result.
[0102] In one embodiment, the resistivity testing module 430 is used to measure the resistivity of the silicon wafer under test using a four-probe method.
[0103] In one embodiment, the silicon wafer to be tested is a silicon wafer with a doping amount less than a threshold.
[0104] Each module in the aforementioned silicon wafer resistivity testing device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.
[0105] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.
[0106] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.
[0107] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A method of testing the resistivity of a silicon wafer, characterized by, The method comprises: controlling the laser beam to heat a surface region of a silicon wafer to be tested, so that the surface temperature of the silicon wafer to be tested reaches a target temperature and continues to heat for a preset time length after reaching the target temperature, so that the oxygen clusters formed in the silicon wafer to be tested are decomposed into interstitial oxygen; controlling the laser beam to leave the surface region of the silicon wafer to be tested; measuring the resistivity of the silicon wafer to be tested under the condition that the silicon wafer to be tested is cooled.
2. The method of claim 1, wherein, Before the control of the laser beam to heat the surface region of the silicon wafer to be tested, the method further comprises: cleaning the silicon wafer to be tested to remove surface oil stains and a cutting damage layer formed in the silicon wafer to be tested during cutting.
3. The method of claim 1, wherein, The control of the laser beam to heat the surface region of the silicon wafer to be tested comprises: controlling the laser beam to scan the surface region of the silicon wafer to be tested in a continuous heating track to heat the surface of the silicon wafer to be tested.
4. The method of claim 3, wherein, The method further comprises: controlling the laser beam to continue to scan the surface region of the silicon wafer to be tested along the heating track for the preset time length after reaching the target temperature, so that the oxygen clusters formed in the silicon wafer to be tested are decomposed into interstitial oxygen.
5. The method of claim 1, wherein, The method further comprises: monitoring the surface temperature of the silicon wafer to be tested by a temperature sensor; when it is monitored that the surface temperature of the silicon wafer to be tested reaches the target temperature, determining the current laser power; keeping the current laser power unchanged and controlling the laser beam to continue to heat the silicon wafer to be tested for a preset time length.
6. The method of claim 1, wherein, Before the measurement of the resistivity of the silicon wafer to be tested under the condition that the silicon wafer to be tested is cooled, the method further comprises: monitoring the surface temperature of the silicon wafer to be tested by a temperature sensor; when it is monitored that the surface temperature of the silicon wafer to be tested reaches room temperature, determining that the silicon wafer to be tested is cooled.
7. The method of claim 1, wherein, After the measurement of the resistivity of the silicon wafer to be tested under the condition that the silicon wafer to be tested is cooled, the method further comprises: determining the theoretical resistivity of the silicon wafer to be tested according to the doping amount of the silicon wafer to be tested; comparing the measured resistivity with the theoretical resistivity to determine the test accuracy according to the comparison result.
8. The method of claim 1, wherein, The measurement of the resistivity of the silicon wafer to be tested under the condition that the silicon wafer to be tested is cooled comprises: measuring the resistivity of the silicon wafer to be tested by a four-probe method.
9. The method of claim 1, wherein, The silicon wafer to be tested is a silicon wafer with a doping amount less than a threshold value.
10. A silicon wafer resistivity testing apparatus, characterized by, The device comprises: a laser heating module configured to emit a laser beam to heat a surface region of a silicon wafer to be tested; a heating control module configured to control the laser beam to perform a heating operation, so that the surface temperature of the silicon wafer to be tested reaches a target temperature and continues to heat for a preset time length after reaching the target temperature, so that the oxygen clusters formed in the silicon wafer to be tested are decomposed into interstitial oxygen, and after the heating ends, the laser beam is controlled to leave the surface region of the silicon wafer to be tested; a resistivity testing module configured to measure the resistivity of the silicon wafer to be tested under the condition that the silicon wafer to be tested is cooled.