Wafer test probe
By designing a probe boss with a raised portion, a triangular support structure is formed to reduce the contact area between the probe and the wafer, the pressure loss problem caused by carrier concentration testing in SiC epitaxial sheet production is solved, and the effect of reducing manufacturing costs and improving production efficiency is achieved.
Patent Information
- Application Number
- CN202421073886.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-16
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-05-16
AI Technical Summary
In the production and manufacturing of existing SiC epitaxial sheets, the contact between the probe and the wafer during carrier concentration test leads to pressure loss, resulting in high manufacturing costs and low production efficiency.
A wafer test probe including a probe body and a boss is designed. The boss is composed of a body part and a boss. The protrusion and the body part form a triangular support to reduce the contact area between the probe and the chip.
It effectively reduces the probability of chip pressure loss, reduces manufacturing costs, improves production line efficiency, and promptly detects the probe status, reducing repeated cleaning and detection.
Smart Images
Figure CN222800811U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of silicon carbide epitaxial wafer production, in particular to a wafer test probe suitable for testing silicon carbide carrier concentration. Background Art
[0002] Silicon carbide (SiC) semiconductor materials have the advantages of high thermal conductivity, high breakdown field strength, high saturated electron drift rate and high bonding energy, which can well meet the application requirements of modern electronic technology under harsh conditions such as high temperature, high power, high voltage, high frequency and high radiation. SiC epitaxial wafers are the key raw materials of SiC power electronic devices. In addition to the epitaxial growth process on SiC substrate wafers, the preparation of SiC epitaxial wafers also requires cleaning, polishing, testing and other processes and steps before and after epitaxial growth to form a complete SiC epitaxial wafer production line.
[0003] The existing SiC epitaxial wafer production and manufacturing requires testing of the epitaxially grown wafers, mainly testing surface defects, epitaxial thickness, carrier concentration, surface warpage, surface roughness, etc. Among them, the capacitance-voltage (CV) method is generally used to detect the carrier concentration, that is, the surface of the wafer is directly contacted with the probe to form a good metal-conductor junction, and then the junction capacitance C is formed. This is the principle of CV measurement. However, in the process of contact between the surface of the wafer and the probe, some fallen particles on the wafer will penetrate into the probe surface in the probe, so when the probe and the wafer contact again, it will cause pressure loss of the SiC wafer. Since SiC power electronic devices are all prepared on the Si surface, the surface quality of the Si surface is crucial to the performance of the device.
[0004] In order to prevent the probe from causing serious pressure loss to the SiC wafer, the existing method is to check the surface condition of the probe twice a day, and if pressure loss is found, PM is carried out in time. The disadvantages of the existing method are: First, when the probe surface abnormality is found, pressure loss has already occurred, which causes preparation risks and yield losses for downstream power devices. Secondly, after pressure loss occurs, it is necessary to detect it through means such as photoluminescence (PL), which will cause a large number of rework operations such as repeated cleaning and repeated testing, which greatly restricts the production capacity of the SiC epitaxial production line; and there is currently no better way to reduce pressure loss, which leads to higher manufacturing costs of SiC wafers.
[0005] Therefore, it is necessary to provide a test probe that can reduce the pressure loss on the wafer, thereby reducing the manufacturing cost of SiC wafers and improving the efficiency of the production line. Utility Model Content
[0006] The utility model aims to provide a test probe capable of reducing pressure loss on a wafer, thereby reducing the manufacturing cost of SiC wafers and improving production line efficiency.
[0007] To achieve the above-mentioned purpose, the technical solution of the utility model is as follows: a wafer test probe is provided, which includes a probe body and a boss; the boss is arranged at the center of the probe body, the boss includes a main body part and a raised part protruding from the outer wall of the main body part, the center of the main body part is provided with a mercury outlet hole running through from top to bottom, and the raised part is provided with a vacuum hole running through from top to bottom.
[0008] Preferably, the maximum distance between the center of the main body and the edge of the raised portion is less than or equal to 2.5 mm, and therefore, the maximum radius of the boss is reduced compared to the 4 mm setting in the prior art. Moreover, except for the position where the raised portion is set, the radius of the main body is much smaller than 4 mm in the prior art, thereby reducing the contact area between the boss and the wafer by about 39% compared to the prior art. Since the contact area of the probe is reduced, the probability of wafer pressure loss can be effectively reduced, and when the probe is punctured, the vacuum ring will be damaged and mercury cannot be discharged normally, thereby ensuring that pressure loss can be discovered and PM can be detected in time.
[0009] Preferably, the main body is cylindrical, and the mercury outlet hole is opened at the center of the main body and is arranged concentrically with the main body, so that the line connecting the protrusion and the two sides of the main body forms a triangle, so that the wafer can be stably supported, ensuring that the contact between the wafer and the probe is stable, and the probe will not be skewed due to the small contact area when in contact, thereby avoiding the situation where the test cannot be performed.
[0010] Preferably, the radius of the mercury outlet hole is 0.8 mm to 1.0 mm, so that the contact area between mercury and the wafer can be kept stable at 0.02 cm 2 So as to ensure the accuracy of the test results.
[0011] Preferably, the height of the boss is less than or equal to 1.75 mm.
[0012] Preferably, the boss is in the shape of a teardrop, a triangle or a gourd, so that the line connecting the raised portion and the two sides of the main body forms a triangle, which on the one hand forms a stable support for the wafer, ensuring that the probe will not tilt when contacting the wafer but is in horizontal contact with the wafer, thereby ensuring the vacuum adsorption effect and further ensuring the stability of the wafer test results, and on the other hand, the outer diameter of the main body is reduced as much as possible to reduce the contact area with the wafer, so as to effectively reduce the probability of wafer pressure loss.
[0013] Preferably, a vacuum groove surrounding the mercury outlet hole is concavely provided on the boss, and the vacuum hole runs through the bottom surface of the vacuum groove. Therefore, the wafer can be stably adsorbed on the boss by vacuum adsorption to ensure the accuracy of detection.
[0014] Preferably, the vacuum groove includes a ring groove and a long groove that are connected, the ring groove surrounds the mercury outlet hole and is concentrically arranged with the mercury outlet hole, the long groove is opened in the protruding portion and extends along the radial direction of the main body, and the vacuum hole is located in the long groove, thereby making the wall near the vacuum hole thicker, so that it can be ensured that the vacuum will not leak to the greatest extent during vacuum suction, thereby stably adsorbing the wafer.
[0015] Preferably, the width of the vacuum groove is 0.4mm~0.5mm. A narrower vacuum groove can ensure a smaller probe area, but a vacuum groove that is too small is too difficult to process and difficult to control during detection, which can easily lead to excessive vacuum degree and thus excessive contact force with the chip. Therefore, the width of the vacuum groove is set to 0.4mm~0.5mm, which reduces the difficulty of processing on the one hand and facilitates the control of the vacuum degree on the other.
[0016] Preferably, the vacuum hole and the mercury outlet hole both penetrate the bottom of the probe body and the top of the boss, and the vacuum hole is inclined relative to the mercury outlet hole.
[0017] Preferably, the angle between the center line of the vacuum hole and the center line of the mercury outlet hole is 5° to 8°.
[0018] Preferably, the probe body is also provided with a plurality of mounting holes, each of which is arranged at the periphery of the boss and evenly distributed around the boss, and the mounting holes are used to detachably mount the probe body on the test platform, and when the probe needs to be replaced or maintained, the probe can be removed from the test platform.
[0019] Compared with the prior art, the wafer test probe of the utility model has a boss arranged on the probe body, which includes a main body and a raised portion protruding from the outer wall of the main body, a mercury outlet hole penetrating up and down is opened in the center of the main body, and a vacuum hole penetrating up and down is opened in the raised portion. Therefore, by adding the raised portion, the raised portion is used to assist in supporting the wafer, so that the raised portion and the main body form a triangular support for the wafer, ensuring the stability of the support, while reducing the outer diameter of the main body, thereby reducing the area of the boss as a whole, so that the contact area between the boss and the wafer is greatly reduced as a whole, thereby effectively reducing the probability of wafer pressure loss. At the same time, since the contact area between the boss and the wafer is small, when the probe is punctured, the vacuum ring will be damaged and mercury cannot be discharged normally. Therefore, the state of the probe is known, and it can be ensured that pressure loss can be discovered and PM in time, reducing pressure loss and thus reducing manufacturing costs, and reducing repeated cleaning and repeated testing to increase the production capacity of the SiC epitaxial production line, and also reducing the preparation risk of downstream power devices. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a structural schematic diagram of a wafer test probe of the utility model.
[0021] Figure 2 yes Figure 1 Top view of the .
[0022] Figure 3 yes Figure 2 Schematic diagram of the support position of the center boss.
[0023] Figure 4 yes Figure 1 An angled side view.
[0024] Figure 5 yes Figure 1 Side view from another angle. DETAILED DESCRIPTION
[0025] The embodiments of the present invention are now described with reference to the accompanying drawings, in which similar element numbers represent similar elements. It should be noted that the orientation descriptions involved in the present invention, such as the orientations or positional relationships indicated by up, down, left, right, front, and back, are all based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the present application or / and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present application. The first, second, etc. described are only used to distinguish technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0026] Combine first Figure 1-Figure 5 As shown, the wafer test probe 100 provided by the utility model is particularly suitable for carrier concentration test equipment, for contacting epitaxial wafers and performing carrier concentration test. However, it is not limited thereto, and can of course also be used in other test equipment for epitaxial wafers and other test equipment for other similar products.
[0027] Continue to combine Figure 1-Figure 5 As shown, in the utility model, the wafer test probe 100 includes a probe body 110 and a boss 120. The boss 120 is arranged at the center of the probe body 110, and the boss 120 includes a body part 120a and a raised part 120b raised on the outer wall of the body part 120a. A mercury outlet hole 121 is provided in the center of the body part 120a and is penetrated from top to bottom, and a vacuum hole 122 is provided in the raised part 120b and is penetrated from top to bottom, that is, the mercury outlet hole 121 and the vacuum hole 122 both penetrate the top of the boss 120 and the bottom of the probe body 110, and the vacuum hole 122 is used to connect a vacuum pumping device, so that the wafer can be adsorbed on the boss 120 through vacuum adsorption to avoid the wafer from moving during detection, and the mercury outlet hole 121 is used to discharge mercury to contact with the wafer to realize testing. The probe 100 in the present application assists in supporting the wafer by providing a protrusion 120b on the side wall of the main body 120a, while reducing the outer diameter of the main body 120a, thereby reducing the outer diameter of the boss 120 as a whole and thus reducing the contact area between the boss 120 and the wafer, thereby effectively reducing the probability of wafer pressure loss. At the same time, since the contact area of the probe 100 is small, when the probe 100 is punctured, the vacuum ring will be damaged and mercury cannot be discharged normally. In this way, the state of the probe 100 is known, and it can be ensured that pressure loss can be discovered and PM in time, thereby reducing the pressure loss rate during wafer testing.
[0028] Continue to combine Figure 1-Figure 3 As shown, in one embodiment of the present invention, the main body 120a is cylindrical. Figure 2 The mercury outlet hole 121 is opened at the center of the main body 120a and is arranged concentrically with the main body 120a. The protrusion 120b protrudes along the radial direction of the main body 120a, and the connection position between the protrusion 120b and the main body 120a is an arc-shaped transition. The maximum outer diameter of the protrusion 120b is much smaller than the diameter of the main body 120a. Figure 2 As shown, the area of the protrusion 120b is reduced. Therefore, on the top surface of the boss 120, the line connecting the protrusion 120b and the two sides of the body 120a can form a triangle abc (see Figure 3), that is to say, the boss 120 can form a triangular support for the wafer, so that, on the one hand, a stable support for the wafer is formed, thereby ensuring that the contact between the wafer and the probe 100 is stable, and the probe 100 will not be skewed due to the small contact area during contact, thereby avoiding the situation where the test cannot be performed, thereby ensuring the stability of the wafer test results, and on the other hand, reducing the overall area of the boss 120 as much as possible, thereby reducing the contact area between the boss 120 and the wafer, which can effectively reduce the probability of wafer pressure damage.
[0029] Combination Figure 1-3 As shown, in the present invention, since the protrusion 120b is a protrusion structure with a smaller outer diameter protruding along the radial direction of the main body 120a, the boss 12 is generally in a water drop shape, a triangle shape, a gourd shape, etc. In a specific embodiment, the boss 12 is generally in a water drop shape. Of course, the shape of the boss 12 is not limited to this shape.
[0030] Next, continue to combine Figure 1-Figure 3 As shown, in one embodiment of the present invention, the radius R1 of the main body 120a is less than or equal to 2 mm. Figure 2 The maximum distance between the center of the main body 120a and the edge of the protrusion 120b is less than or equal to 2.5 mm, or in other words, the maximum radius R2 of the protrusion 120b is less than or equal to 2.5 mm, see Figure 2 As shown. In a specific embodiment, the maximum distance between the center of the main body 120a and the edge of the raised portion 120b is set to 2.5mm, that is, the maximum radius R2 of the raised portion 120b is 2.5mm. Therefore, the maximum radius R2 of the boss 120 is reduced compared with the 4mm setting in the prior art. Moreover, except for the position where the raised portion 120b is set, the radius R1 of the main body 120a is less than or equal to 2mm, which is only half of the 4mm in the prior art. Therefore, the area of the boss 120 in contact with the wafer as a whole can be reduced by about 39% compared with the prior art. In this way, the contact area between the probe 100 and the wafer is reduced as a whole, which can effectively reduce the probability of wafer pressure loss. At the same time, since the contact area of the probe 100 is small, when the probe 100 is punctured, it will cause the vacuum ring to be damaged and mercury cannot be discharged normally, thereby ensuring that pressure loss can be discovered and PM can be detected in time.
[0031] Continue to view Figure 2 As shown, in one embodiment of the present invention, the radius R3 of the mercury outlet hole 121 is preferably 0.8 mm to 1.0 mm. In a specific embodiment, the radius R3 of the mercury outlet hole 121 is set to 0.8 mm, which can ensure that the contact area between mercury and the wafer is stable at 2 mm. 2 (0.02cm2 ), thereby ensuring the accuracy of the test result. Of course, the radius R3 of the mercury outlet hole 121 is not limited to that in this specific implementation.
[0032] Combine the following Figure 4-Figure 5 As shown, in one embodiment of the utility model, the height H1 of the boss 120 is less than or equal to 1.75 mm. In a specific embodiment, the height H1 of the boss 120 is set to 1.75 mm to ensure stable support of the wafer. Of course, the height H1 of the boss 120 is not limited to this and can be flexibly set according to test needs.
[0033] Combine again Figure 1-Figure 3 As shown, in one embodiment of the utility model, the boss 120 is provided with a vacuum groove 123 surrounding the mercury outlet hole 121, and the vacuum groove 123 includes a connected annular groove 123a and a long groove 123b, the annular groove 123a is recessed in the body portion 120a around the mercury outlet hole 121, and the annular groove 123a is concentrically arranged with the mercury outlet hole 121, the long groove 123b is provided in the convex portion 120b and extends along the radial direction of the body portion 120a, and the vacuum hole 122 is provided in the long groove 123b, see Figure 2 As shown, the wall near the vacuum hole 122 is made thicker, so that the vacuum will not leak to the greatest extent during vacuum suction, thereby stably adsorbing the wafer.
[0034] In this embodiment, the width of the vacuum groove 123 is preferably 0.4 mm to 0.5 mm. For the probe of the test wafer, setting a narrower vacuum groove 123 can ensure that the probe area is smaller, but a too narrow vacuum groove 123 is too difficult to process and difficult to control during detection, which can easily lead to excessive vacuum and excessive contact force with the wafer, affecting the test results. Therefore, in this embodiment, the width of the vacuum groove 123 is set to 0.4 mm to 0.5 mm, preferably 0.5 mm, which reduces the difficulty of processing on the one hand, and facilitates the control of the vacuum degree on the other hand to ensure the effectiveness of the test.
[0035] Combine the following Figure 2-Figure 5 As shown, in one embodiment of the present invention, the vacuum hole 122 is inclined relative to the mercury outlet hole 121. Specifically, the angle between the center line of the vacuum hole 122 and the center line of the mercury outlet hole 121 is preferably set to 5° to 8°. In a specific embodiment, the angle between the two is set to 6°, but it is not limited to this angle.
[0036] Combine again Figure 1-Figure 3As shown, in the present invention, the probe body 110 is also provided with a plurality of mounting holes 130, each of which is provided at the periphery of the boss 120 and evenly distributed around the boss 120. In a specific embodiment, four mounting holes 130 are provided, and the four mounting holes 130 are evenly distributed around the boss 120, that is, the central angle between the centers of any two adjacent mounting holes 130 is 90°. The mounting holes 130 are used to detachably mount the probe body 110 on the test platform, for example, the probe body 110 is locked on the test platform with screws, and when the probe needs to be replaced or maintained, the screws are removed to remove the probe from the test platform. Of course, it is not limited to locking the probe body 110 with screws.
[0037] See also Figure 2-3 As shown, in one embodiment of the present invention, each mounting hole 130 is preferably a stepped hole, and the radius R4 of the inner circle of the mounting hole 130 is preferably set to 1.5 mm, and the radius R5 of the outer circle of the mounting hole 130 is preferably set to 2.25 mm. Of course, the size of the mounting hole 130 is not limited to that in this embodiment.
[0038] Combine again Figure 2-4 As shown, in one embodiment of the present invention, the radius R6 of the probe body 110 is preferably set to 12.25 mm, that is, the diameter of the probe body 110 is preferably 24.5 mm, and the height H2 of the probe body 110 is preferably 8 mm. It can be seen that the probe body 110 in the present application has a relatively small size. Of course, the size of the probe body 110 is not limited to that in the present embodiment.
[0039] Combine again Figure 1-5 As shown, in the present invention, the test probe 100 is preferably formed in one piece by polyetheretherketones (PEEK) material. PEEK material can still maintain good electrical insulation performance under harsh working conditions such as high temperature, high pressure and high humidity, so as to ensure the accuracy of the test results. Of course, the test probe 100 can also be formed by other materials.
[0040] In summary, in the wafer test probe 100 of the present invention, the boss 120 arranged on the probe body 110 includes a main body 120a and a raised portion 120b protruding from the outer wall of the main body 120a. The raised portion 120b is used to assist in supporting the wafer, so that the raised portion 120b and the main body 120a form a triangular support for the wafer, ensuring the stability of the support, while reducing the outer diameter of the main body 120a, thereby reducing the area of the boss 120 as a whole, so that the contact area between the boss 120 and the wafer is greatly reduced as a whole, so as to effectively reduce the probability of wafer pressure loss. At the same time, since the contact area of the boss 120 is small, when the probe 100 is punctured, the vacuum ring will be damaged and mercury cannot be discharged normally. Therefore, the state of the probe 100 is known, and it can be ensured that pressure loss can be discovered and PM in time, reducing pressure loss and thus reducing manufacturing costs, and reducing repeated cleaning and repeated testing to improve the production capacity of the SiC epitaxial production line, and also reduce the preparation risk of downstream power devices.
[0041] The structures of other parts of the carrier concentration testing device involved in the present invention are conventional structures well known to ordinary technicians in the field, and will not be described in detail here.
[0042] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.
Claims
1. A wafer test probe, characterized in that: include: Probe body; The boss is arranged at the center of the probe body, and the boss comprises a main body and a raised part protruding from the outer wall of the main body. A mercury outlet hole is opened in the center of the main body and a vacuum hole is opened in the raised part.
2. The wafer test probe according to claim 1, wherein: A maximum distance between a center of the main body and an edge of the raised portion is less than or equal to 2.5 mm.
3. The wafer test probe according to claim 1, wherein: The main body is cylindrical, and the mercury outlet is opened at the center of the main body and is concentrically arranged with the main body.
4. The wafer test probe according to claim 1, wherein: The radius of the mercury outlet hole is 0.8 mm to 1.0 mm.
5. The wafer test probe according to claim 1, wherein: The boss is in a water drop shape, a triangle shape or a gourd shape.
6. The wafer test probe according to any one of claims 1 to 5, characterized in that: The boss is concavely provided with a vacuum groove surrounding the mercury outlet hole, and the vacuum hole passes through the bottom surface of the vacuum groove.
7. The wafer testing probe as claimed in claim 6, characterized in that: The vacuum groove comprises a ring groove and a long groove which are connected to each other. The ring groove surrounds the mercury outlet hole and is arranged concentrically with the mercury outlet hole. The long groove is opened in the protruding part and extends along the radial direction of the main body.
8. The wafer testing probe as claimed in claim 6, characterized in that: The width of the vacuum groove is 0.4 mm to 0.5 mm.
9. The wafer testing probe according to claim 1, wherein: The vacuum hole and the mercury outlet hole both penetrate the bottom of the probe body and the top of the boss, and the vacuum hole is inclined compared to the mercury outlet hole.
10. The wafer test probe according to any one of claims 1 to 5 and 9, characterized in that: The probe body is also provided with a plurality of mounting holes, each of which is arranged at the periphery of the boss and evenly distributed around the boss.