Conductivity test method that can automatically locate the position and size of a silicon wafer
By combining eddy current probes and photodetectors, the position and size of silicon wafers can be automatically located, solving the risks and size adaptability problems caused by manual positioning and achieving efficient and accurate conductivity measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 九域半导体科技(苏州)有限公司
- Filing Date
- 2022-01-10
- Publication Date
- 2026-05-19
AI Technical Summary
Current silicon wafer conductivity testing requires manual positioning, which increases the risk of human contact and is difficult to adapt to silicon wafers of different sizes, making the operation inconvenient.
Using two photodetectors, an eddy current probe and a motion assembly, the silicon wafer is automatically positioned and its size is determined through linear uniform motion and rotational motion. The relative position between the center of the silicon wafer and the eddy current probe is calculated using a formula, thereby enabling automatic measurement of conductivity.
No manual adjustment of the silicon wafer position is required, reducing human intervention, improving measurement accuracy and efficiency, and adapting to the testing of silicon wafers of different specifications.
Smart Images
Figure CN117214529B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor material performance parameter testing, specifically to a conductivity testing method that can automatically locate the position and size of a silicon wafer. This method can be used to accurately locate the position and size of the silicon wafer in order to comprehensively measure the conductivity values at various locations on the surface of the silicon wafer. Background Technology
[0002] In semiconductor manufacturing, the performance of end products depends on the performance of semiconductor materials. To ensure that the measurement process does not affect the quality of the end products, non-contact measurement methods are widely used to measure the performance of semiconductor materials. Non-contact measurement methods are non-destructive and do not introduce new defects. In particular, non-contact measurement methods greatly improve the yield of products during the production process.
[0003] Electrical conductivity is a fundamental parameter of semiconductor materials. Influenced by various factors during the manufacturing process, the conductivity at different locations on the silicon wafer surface typically varies. Measuring the conductivity at these locations is necessary to determine the wafer's quality. During measurement, the entire surface of the silicon wafer needs to be measured according to pre-designed measurement points, generally distributed circumferentially around the wafer's center. To meet these requirements, existing testing instruments require manual precision positioning of the silicon wafer during fixing, adding multiple human contact steps and increasing the risk to wafer quality control. Furthermore, existing testing instruments also require manual adjustment of parameters when testing silicon wafers of different sizes, causing inconvenience in on-site operation. Therefore, to solve the positional accuracy problem during measurement, a simpler and more reliable method or structure is needed. Summary of the Invention
[0004] This invention aims to solve at least one of the technical problems existing in the prior art. This invention proposes a conductivity testing method that can automatically locate the position and size of a silicon wafer, comprising:
[0005] The silicon wafer under test is placed on a test platform. Eddy current probes, equipped with two photodetectors for detecting the pre-existing object, are in working mode and positioned at the working height of the photodetectors. A motion assembly is used to drive the silicon wafer under test through two linear uniform motions. During the first motion, timing begins when the two photodetectors detect the edge of the silicon wafer for the first time, and ends when the two photodetectors detect the edge of the silicon wafer for the second time, thus generating data for the first linear uniform motion. Then, the motion assembly rotates the silicon wafer under test by 90 degrees and drives it through a second linear uniform motion. Timing begins again when the two photodetectors detect the edge of the silicon wafer for the first time, and ends when the two photodetectors detect the edge of the silicon wafer for the second time, thus generating data for the second linear uniform motion.
[0006] The two photodetectors are a left photosensitive sensor and a right photosensitive sensor. The eddy current probe is placed at the center of the line connecting the two photodetectors. The distance between the central axis of the eddy current probe and the central axis of the photodetector is L. The distance between the central axis of the photodetector that is far from the center of the silicon wafer under test and the diameter parallel to the motion trajectory is Lx. The radius of the silicon wafer and its relative position in the current direction can be determined by the following formula.
[0007]
[0008] Where: V is the velocity value of the platform moving at a constant speed, t1 and t2 are the light-sensing times of the left and right photoelectric sensors, and R is the radius of the silicon wafer. The distance from the center of the silicon wafer to the center of the eddy current probe during the first direction of motion;
[0009] Simultaneously, using the above formula, the distance T from the center of the silicon wafer to the center of the eddy current probe during the second motion direction can be obtained. y According to the calculation and The value is obtained by moving the silicon wafer under test so that the center of the silicon wafer under test is precisely positioned with the center of the eddy current probe, and the conductivity of the test position of the silicon wafer under test is measured based on this positioning.
[0010] The conductivity testing method of the present invention, which can automatically locate the position and size of silicon wafers, uses two reflective photoelectric sensors to determine the position of the edge of the silicon wafer, and then automatically obtains the placement center position and size of the silicon wafer through calculation. During the test, there is no need to manually adjust the position of the silicon wafer, reducing the intervention of manual operation on the silicon wafer.
[0011] In addition, the conductivity testing method for automatically locating the position and size of a silicon wafer disclosed in this invention also has the following additional technical features:
[0012] Furthermore, the photodetector includes an internal constant light source for emitting light and an optoelectronic device for receiving the emitted light from the constant light source.
[0013] Furthermore, the eddy current probe includes a probe at the center position. The probe, the left photoelectric sensor, and the right photoelectric sensor are mounted on a base. The base has a hole in the middle for mounting the probe and two parts on both sides for mounting the photodetector. The lower surface of the probe and the lower surface of the photodetector are on the same horizontal plane, and the center lines of the three coincide in the top view.
[0014] Furthermore, the silicon wafer under test is provided with regularly arranged test positions.
[0015] Furthermore, the motion assembly includes a Y-axis module mounted on a support base, an X-axis module mounted on the Y-axis module, and a rotary module mounted on the X-axis module, with the test platform mounted on the rotary module.
[0016] Furthermore, the X-axis module and the Y-axis module are installed vertically.
[0017] Furthermore, the eddy current probe is mounted on the lifting shaft of the gantry frame mounted on the support base.
[0018] Furthermore, a displacement sensor is installed on the eddy current probe.
[0019] Furthermore, the gantry frame on the support base is a U-shaped frame, including two side columns installed on the support base and the lifting shaft installed on the columns.
[0020] Preferably, a display for displaying data is installed on the column.
[0021] Additional aspects and advantages of embodiments of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0023] Figure 1 This is a schematic diagram of the photoelectric sensor structure in this invention;
[0024] Figure 2 This is a schematic diagram showing the positions of the probe and the photoelectric sensor in the eddy current probe of the present invention;
[0025] Figure 3 for Figure 2 Top view of the structure;
[0026] Figure 4 This is a schematic diagram of the mounting base structure for the eddy current probe and photoelectric sensor of the present invention;
[0027] Figure 5 This is a schematic diagram illustrating the principle of calculating the center position and size of the silicon wafer according to the present invention;
[0028] Figure 6 This is a schematic diagram of the silicon wafer test position distribution according to the present invention;
[0029] Figure 7 This is a schematic diagram of the overall device structure according to a specific embodiment of the present invention;
[0030] Among them, A is the photoelectric sensor, A1 is the photoelectric device, A2 is the constant light source, B is the object under test, C is the eddy current probe, C1 is the probe, C2 is the right photoelectric sensor, C3 is the left photoelectric sensor, C12 is the hole for mounting the probe, C21 and C31 are the mounting parts for the photodetector, D is the silicon wafer, D2 is the test position, E1 is the gantry frame, E11 is the column, E12 is the display, F is the support base, F1 is the Y-axis module, F2 is the X-axis module, F3 is the rotary module, F4 is the test platform, and F5 is the lifting axis. Detailed Implementation
[0031] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.
[0032] According to embodiments of the present invention, a conductivity testing method for automatically locating the position and size of a silicon wafer is proposed, comprising:
[0033] The silicon wafer under test is placed on a test platform. Eddy current probes, equipped with two photodetectors for detecting the pre-existing object, are in working mode and positioned at the working height of the photodetectors. A motion assembly is used to drive the silicon wafer under test through two linear uniform motions. During the first motion, timing begins when the two photodetectors detect the edge of the silicon wafer for the first time, and ends when the two photodetectors detect the edge of the silicon wafer for the second time, thus generating data for the first linear uniform motion. Then, the motion assembly rotates the silicon wafer under test by 90 degrees and drives it through a second linear uniform motion. Timing begins again when the two photodetectors detect the edge of the silicon wafer for the first time, and ends when the two photodetectors detect the edge of the silicon wafer for the second time, thus generating data for the second linear uniform motion.
[0034] The two photodetectors are a left photosensitive sensor and a right photosensitive sensor. The eddy current probe is placed at the center of the line connecting the two photodetectors. The distance between the central axis of the eddy current probe and the central axis of the photodetector is L. The distance between the central axis of the photodetector that is far from the center of the silicon wafer under test and the diameter parallel to the motion trajectory is Lx. The radius of the silicon wafer and its relative position in the current direction can be determined by the following formula.
[0035]
[0036] Where: V is the velocity value of the platform moving at a constant speed, t1 and t2 are the light-sensing times of the left and right photoelectric sensors, and R is the radius of the silicon wafer. The distance from the center of the silicon wafer to the center of the eddy current probe during the first direction of motion;
[0037] Simultaneously, using the above formula, the distance T from the center of the silicon wafer to the center of the eddy current probe during the second motion direction can be obtained. y According to the calculation and The value is obtained by moving the silicon wafer under test so that the center of the silicon wafer under test is precisely positioned with the center of the eddy current probe, and the conductivity of the test position of the silicon wafer under test is measured based on this positioning.
[0038] According to some embodiments of the present invention, the photodetector includes an internal constant light source for emitting light and an optoelectronic device for receiving the emitted light from the constant light source, such as... Figure 1 As shown.
[0039] According to some embodiments of the present invention, the eddy current probe includes a probe at a central position. The probe, the left photoelectric sensor, and the right photoelectric sensor are mounted on a base. The base has a hole in the middle for mounting the probe and portions on both sides for mounting the photodetectors. The lower surface of the probe and the lower surface of the photodetectors are on the same horizontal plane, and the center lines of the three coincide in a top-view direction. Figure 2 , 3 As shown.
[0040] According to some embodiments of the present invention, the silicon wafer under test has regularly arranged test positions, such as... Figure 6 As shown.
[0041] According to some embodiments of the present invention, the motion assembly includes a Y-axis module mounted on a support base, an X-axis module mounted on the Y-axis module, and a rotary module mounted on the X-axis module. The test platform is mounted on the rotary module, such as... Figure 7 As shown.
[0042] Furthermore, the X-axis module and the Y-axis module are installed vertically.
[0043] According to an embodiment of the present invention, the eddy current probe is disposed on the lifting shaft of the gantry frame mounted on the support base.
[0044] Furthermore, a displacement sensor is installed on the eddy current probe.
[0045] Furthermore, the gantry frame on the support base is a U-shaped frame, including two side columns installed on the support base and the lifting shaft installed on the columns.
[0046] Preferably, a display for displaying data is installed on the column.
[0047] According to an embodiment of the present invention, the conductivity tester structure capable of automatically locating the position and size of a silicon wafer is as follows: Figure 7 As shown, the system is a gantry structure. The gantry frame is fixed on the support base. A lifting / Z-axis mounted above the gantry frame drives the eddy current probe and displacement sensor to move up and down. The test platform is located on a motion module composed of the X-axis, Y-axis, and rotary module, allowing for planar and rotary motion. During testing, the silicon wafer is placed arbitrarily on the worktable without needing to adjust its position; the wafer is then held in place by suction. The lifting axis lowers the eddy current probe, and the displacement sensor measures the distance from the probe to the silicon wafer. When the probe reaches a set position, the lifting axis stops. The X-axis module moves the silicon wafer from front to back. When the edge of the wafer passes the photosensitive sensor, the sensor generates a current, and the system starts timing. When the edge of the wafer leaves the photosensitive sensor, the system stops timing. The rotary module rotates the silicon wafer 90 degrees, and the above actions are repeated. The system calculates the distance between the center of the silicon wafer and the center of the eddy current probe, moves it to the corresponding position, and then, according to the set graphic requirements, moves the silicon wafer to the set position and measures the conductivity value at the current position. This process continues until all measurement positions are completed, at which point the worktable resets and the silicon wafer is released.
[0048] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A conductivity testing method that can automatically locate the position and size of a silicon wafer, characterized in that, include: The silicon wafer under test is placed on a test platform. Eddy current probes, equipped with two photodetectors for detecting the pre-existing object, are in working mode and positioned at the working height of the photodetectors. A motion assembly is used to drive the silicon wafer under test through two linear uniform motions. During the first motion, timing begins when the two photodetectors detect the edge of the silicon wafer for the first time, and ends when the two photodetectors detect the edge of the silicon wafer for the second time, thus generating data for the first linear uniform motion. Then, the motion assembly rotates the silicon wafer under test by 90 degrees and drives it through a second linear uniform motion. Timing begins again when the two photodetectors detect the edge of the silicon wafer for the first time, and ends when the two photodetectors detect the edge of the silicon wafer for the second time, thus generating data for the second linear uniform motion. The two photodetectors are a left photosensitive sensor and a right photosensitive sensor. The eddy current probe is placed at the center of the line connecting the two photodetectors. The distance between the central axis of the eddy current probe and the central axis of the photodetector is L. The distance between the central axis of the photodetector that is far from the center of the silicon wafer under test and the diameter parallel to the motion trajectory is Lx. The radius of the silicon wafer and its relative position in the current direction can be determined by the following formula. Where: V is the velocity of the platform moving at a constant speed, t1 and t2 are the photosensitivity times of the left and right photoelectric sensors, and R is the radius of the silicon wafer. The distance from the center of the silicon wafer to the center of the eddy current probe during the first direction of motion; Simultaneously, using the above formula, the distance T from the center of the silicon wafer to the center of the eddy current probe during the second motion direction can be obtained. Y According to the calculation and The value is obtained by moving the silicon wafer under test so that the center of the silicon wafer under test is precisely positioned with the center of the eddy current probe, and the conductivity of the test position of the silicon wafer under test is measured based on this positioning.
2. The conductivity testing method for automatically locating the position and size of a silicon wafer as described in claim 1, characterized in that, The photodetector includes an internal constant light source for emitting light and an optoelectronic device for receiving the emitted light from the constant light source.
3. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 1, characterized in that, The eddy current probe includes a probe at the center position. The probe, the left photoelectric sensor, and the right photoelectric sensor are mounted on a base. The base has a hole in the middle for mounting the probe and two parts on both sides for mounting the photodetector. The lower surface of the probe and the lower surface of the photodetector are on the same horizontal plane, and the center lines of the three coincide in the top view.
4. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 1, characterized in that, The silicon wafer under test has test positions arranged in a regular pattern.
5. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 1, characterized in that, The motion assembly includes a Y-axis module mounted on a support base, an X-axis module mounted on the Y-axis module, and a rotary module mounted on the X-axis module, with the test platform mounted on the rotary module.
6. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 5, characterized in that, The X-axis module and the Y-axis module are installed vertically.
7. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 1, characterized in that, The eddy current probe is mounted on the lifting shaft of the gantry frame, which is installed on the support base.
8. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 7, characterized in that, A displacement sensor is installed on the eddy current probe.
9. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 7, characterized in that, The gantry frame on the support base is a U-shaped frame, including two side columns installed on the support base and the lifting shaft installed on the columns.
10. The conductivity testing method for automatically locating the position and size of a silicon wafer according to claim 9, characterized in that, A display for showing data is installed on the column.