Test probe capable of reducing contact area

Abstract

The utility model discloses a test probe capable of reducing contact area, which comprises a probe body, a boss and a plurality of support columns, the boss and the support columns are arranged on the probe body, the support columns are equally distributed around the boss, and the height of each support column is consistent with that of the boss, so that a wafer is supported in an auxiliary manner by the support columns with smaller diameters during testing, the area of the boss is further reduced, and the test efficiency is improved. Therefore, the contact area of the probe and the wafer is greatly reduced on the whole, the probability of pressure loss of the wafer is effectively reduced, meanwhile, due to the fact that the contact area of the probe is small, when the probe is stabbed, the vacuum ring is damaged, mercury cannot be normally discharged, the state of the probe can be known, PM can be found in time when pressure loss occurs, and the probability of pressure loss of the wafer is effectively reduced. The pressure loss is reduced, the manufacturing cost is reduced, repeated cleaning and repeated detection are reduced, and the productivity of the SiC epitaxial production line is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of silicon carbide epitaxial wafer production, in particular to a test probe applicable to the measurement of the carrier concentration of silicon carbide and capable of reducing the contact area. Background Art

[0002] Silicon carbide (SiC) semiconductor materials have the advantages of high thermal conductivity, high breakdown field strength, high saturated electron drift rate, high bonding energy, etc., and 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 for SiC power electronic devices. The preparation of SiC epitaxial wafers requires not only the epitaxial growth process on SiC substrate wafers, but also the cleaning, grinding, polishing, detection and other processes and steps before and after epitaxial growth to form a complete SiC epitaxial wafer production line.

[0003] The existing production and manufacturing of SiC epitaxial wafers need to test the wafers after epitaxial growth, mainly including 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 a junction capacitance C is formed, which is the principle of CV measurement. However, during the contact process between the surface of the wafer and the probe, some falling particles (Downfall) on the wafer will pierce into the surface of the probe, so when the probe contacts the wafer again, it will cause pressure damage to the SiC wafer. Since SiC power electronic devices are all fabricated on the Si surface, the surface quality of the Si surface is crucial for device performance.

[0004] To prevent the probe from causing serious pressure damage to the SiC wafer, the existing method is to check the surface state of the probe twice a day, and if pressure damage is found, PM is carried out in time. The disadvantages of the existing method are as follows: First, when the abnormality of the probe surface is found, pressure damage has already occurred, which poses a preparation risk and yield loss to downstream power devices. Second, after pressure damage occurs, it is necessary to detect by means of photoluminescence (PL), etc., which will cause a large number of repeated cleaning and repeated detection and other rework operations, greatly restricting the production capacity of the SiC epitaxial production line; moreover, there is currently no other better way to reduce pressure damage, resulting in a relatively high manufacturing cost of SiC wafers.

[0005] Therefore, it is necessary to provide a test probe capable of reducing the pressure damage to the wafer, thereby reducing the manufacturing cost of SiC wafers and improving the production line efficiency. Summary of the Utility Model

[0006] The purpose of the present utility model is to provide a test probe that can reduce the damage to the wafer, thereby reducing the manufacturing cost of SiC wafers and improving the production line efficiency.

[0007] To achieve the above object, the technical solution of the present utility model is: to provide a test probe with a reduced contact area, which includes a probe body, a boss, and a plurality of struts; the boss is provided at the center of the probe body, a mercury outlet hole penetrating up and down is opened at the center of the boss, and a vacuum hole penetrating up and down is also opened on the boss; each strut protrudes from the probe body and is evenly distributed around the boss, and the height of each strut is the same as the height of the boss.

[0008] Preferably, the strut is cylindrical. By being cylindrical, it can ensure that the contact between the wafer and the probe is stable, and it will not cause the probe to contact obliquely due to the small contact area during contact, thereby avoiding the situation where testing cannot be performed.

[0009] Preferably, the diameter of the strut is less than or equal to 1.0 mm, so as to minimize the contact area with the wafer as much as possible, thereby reducing the contact area as a whole and effectively reducing the probability of wafer damage.

[0010] Preferably, the heights of the strut and the boss are both less than or equal to 0.9 mm, and the radius of the boss is less than or equal to 2 mm. The radius of the boss is reduced by half compared with the 4 mm setting method in the prior art. Therefore, the contact area with the wafer can be reduced by 50% compared with the prior art. Since the contact area of the probe is reduced, the probability of wafer damage can be effectively reduced. And when the probe has a puncture, it will cause the vacuum ring to be damaged and mercury cannot be discharged normally, and then it can ensure that the damage can be detected and PM in time.

[0011] Preferably, three struts are evenly arranged around the boss. On the one hand, the stability of the triangle is used to form a stable support for the wafer, ensuring the effect of vacuum adsorption and thus ensuring the stability of the wafer test result. On the other hand, the number of struts is reduced as much as possible to reduce the contact area with the wafer, so as to effectively reduce the probability of wafer damage.

[0012] Preferably, a ring groove surrounding the mercury outlet hole is recessed on the boss, and the vacuum hole penetrates the bottom surface of the ring groove.

[0013] Preferably, the width of the ring groove is 0.4 mm to 0.5 mm. A narrower ring groove can ensure a smaller probe area. However, an overly small ring groove is too difficult to process and is not easy to control during detection, which is likely to cause too high a vacuum degree and thus too large a contact force with the wafer. Therefore, the width of the ring groove is set to 0.4 mm to 0.5 mm. On the one hand, it reduces the processing difficulty, and on the other hand, it is convenient to control the vacuum degree.

[0014] Preferably, the radius of the mercury outlet hole is 0.8 mm to 1.0 mm, so as to ensure that the contact area between mercury and the wafer is stably around 0.02 cm 2 or so, thereby ensuring the accuracy of the test results.

[0015] Preferably, both the vacuum hole and the mercury outlet hole penetrate through the bottom of the probe body, and the vacuum hole is inclined relative to the mercury outlet hole.

[0016] Preferably, the included angle between the center line of the vacuum hole and the center line of the mercury outlet hole is 5° to 8°.

[0017] Preferably, the vertical distance between the center of the vacuum hole and the center of the mercury outlet hole is 0.9 mm to 1.25 mm.

[0018] Preferably, a plurality of mounting holes are further formed in the probe body. Each mounting hole is arranged outside the support column and evenly distributed around the boss. The mounting holes are used to detachably mount the probe body on the test platform. When the probe needs to be replaced or maintained, the probe can be removed from the test platform.

[0019] Compared with the prior art, since the test probe with reduced contact area of the present invention is provided with a plurality of support columns evenly distributed around the boss on the probe body, and the height of each support column is the same as the height of the boss, a plurality of support columns with smaller diameters are used to assist in supporting the wafer, thereby reducing the area of the boss, so that the contact area between the probe and the wafer is greatly reduced as a whole, effectively reducing the probability of wafer crushing. At the same time, since the contact area of the probe is small, when the probe has a puncture, the vacuum ring will be damaged and mercury cannot be discharged normally, so as to know the state of the probe. Furthermore, it can ensure that the crushing can be detected and PMed in time, reduce the crushing and thus reduce the manufacturing cost, and reduce the repeated cleaning and repeated detection to improve the production capacity of the SiC epitaxial production line, and also reduce the preparation risk of downstream power devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural view of the test probe with reduced contact area of the present invention.

[0021] Figure 2 is Figure 1 the top view.

[0022] Figure 3 is Figure 1 the side view.

[0023] Figure 4 is Figure 1 the side view from another angle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Reference will now be made to the embodiments of the present utility model with reference to the accompanying drawings, in which like reference numerals represent like elements. It should be noted that the orientation descriptions involved in the present utility model, such as the upper, lower, left, right, front, rear, etc., indicating the orientation or positional relationship are all based on the orientation or positional relationship shown in the 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. The first, second, etc. described are only used to distinguish technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0025] First, in combination with Figures 1-4 As shown, the test probe 100 for reducing the contact area provided by the present utility model is particularly applicable to the carrier concentration test equipment, and is used to contact the epitaxial wafer and perform the carrier concentration test. However, it is not limited thereto. Of course, it can also be used on other test equipment for epitaxial wafers and other test equipment for other similar products.

[0026] Continuing to combine with Figures 1-4 As shown, in the present utility model, the test probe 100 for reducing the contact area includes a probe body 110, a boss 120, and a plurality of struts 130. The boss 120 is provided at the center of the probe body 110, and a mercury outlet hole 121 penetrating up and down is provided at the center of the boss 120. A vacuum hole 122 penetrating up and down is also provided on the boss 120. The vacuum hole 122 is used to connect a vacuum pumping device, and the wafer can be adsorbed on the boss 120 through vacuum adsorption to avoid the movement of the wafer during detection. Each strut 130 protrudes from the probe body 110 and is evenly distributed around the boss 120, and the height of each strut 130 is the same as the height of the boss 120. As Figures 3-4 As shown, the struts 130 are provided to assist in supporting the wafer, so that the outer diameter of the boss 120 can be reduced to reduce its contact area with the wafer, thereby reducing the contact area between the probe and the wafer as a whole, effectively reducing the probability of wafer crushing. At the same time, since the contact area of the probe is small, when the probe has a puncture, the vacuum ring will be damaged and mercury cannot be discharged normally, so the state of the probe can be known, and then it can be ensured that the crushing can be detected and PM in time, reducing the crushing rate during wafer testing.

[0027] Continuing to combine with Figures 1-4As shown, in an embodiment of the present utility model, the pillar 130 is cylindrical, and the diameter of the pillar 130 is less than or equal to 1.0 mm. In a specific embodiment, the diameter of the pillar 130 is set to 1.0 mm. First, setting the cylindrical pillar 130 can ensure the stable contact between the wafer and the pillar 130, and will not cause the probe to contact obliquely due to the small contact area during contact, thus avoiding the situation of unable to test. Secondly, the diameter of the pillar 130 is less than or equal to 1.0 mm, so that the contact area with the wafer is reduced as much as possible, thereby reducing the contact area of the probe as a whole, and effectively reducing the probability of wafer damage. Of course, the pillar 130 is not limited to a cylindrical shape, and it is also feasible to set it to other shapes that can stably support and have a small end face area.

[0028] In a specific embodiment, three pillars 130 are provided, and the three pillars 130 are equally distributed around the boss 120 at 360°, that is, the central angle between any two adjacent pillars 130 is 120°, as Figure 2 shown. This setting method, on the one hand, uses the stability of the triangle to form a stable support for the wafer, ensuring the effect of vacuum adsorption, and then ensuring the stability of the wafer test result. On the other hand, the number of pillars 130 is reduced as much as possible to reduce the contact area with the wafer as a whole, thereby effectively reducing the probability of wafer damage. It can be understood that the number of the pillars 130 is not limited to this, and of course, it can be flexibly set according to the test requirements.

[0029] The following combination Figures 1-2 As shown, in an embodiment of the present utility model, the radius R1 of the boss 120 is less than or equal to 2 mm. In a specific embodiment, the radius R1 of the boss 120 is set to 2 mm. The radius R1 of the boss 120 is reduced by half compared with the setting method of 4 mm in the prior art. Therefore, the contact area with the wafer can be reduced by 50% compared with the prior art. And in this specific embodiment, the diameter of the pillar 130 is only 1.0 mm, and its contact area with the wafer is also small. Therefore, the contact area between the probe 100 and the wafer is reduced as a whole, which can effectively reduce the probability of wafer damage. At the same time, because the contact area of the probe 100 is small, when the probe 100 has a puncture, the vacuum ring will be damaged and mercury cannot be discharged normally, and thus it can be ensured that the damage can be detected and PM in time.

[0030] The following combination Figures 3-4As shown, in an embodiment of the present utility model, the heights of the pillar 130 and the boss 120 are equal and both are less than or equal to 0.9 mm. In a specific embodiment, the heights of both are set to 0.9 mm to ensure stable support of the wafer. Of course, the heights of the pillar 130 and the boss 120 are not limited to this, and can be flexibly set according to test requirements.

[0031] Combined with Figures 1-2 As shown, in an embodiment of the present utility model, a ring groove 123 surrounding the mercury outlet hole 121 is recessed on the boss 120. The width of the ring groove 123 is preferably 0.4 mm to 0.5 mm. The vacuum hole 122 penetrates the bottom surface of the ring groove 123, as Figure 2 shown. For the probe of the test wafer, setting a narrower ring groove 123 can ensure a smaller probe area. However, an overly narrow ring groove 123 is too difficult to process, and it is not easy to control during detection, easily resulting in too high a vacuum degree and too large a contact force with the wafer, affecting the test results. Therefore, in this embodiment, the width of the ring groove 123 is set to 0.4 mm to 0.5 mm, preferably 0.5 mm. On the one hand, this reduces the processing difficulty, and on the other hand, it is convenient to control the vacuum degree to ensure the effectiveness of the test.

[0032] In an embodiment of the present utility model, the radius of the mercury outlet hole 121 is preferably 0.8 mm to 1.0 mm. In a specific embodiment, the radius of the mercury outlet hole 121 is set to 0.8 mm, so that the area of contact between mercury and the wafer can be stably maintained at 2 mm 2 (0.02 cm 2 ) or so, thereby ensuring the accuracy of the test results. Of course, the radius of the mercury outlet hole 121 is not limited to that in this specific embodiment.

[0033] Next, referring to Figure 3 As shown, in the present utility model, both the vacuum hole 122 and the mercury outlet hole 121 penetrate the bottom of the probe body 110, and the vacuum hole 122 is inclined with respect to the mercury outlet hole 121. Specifically, the included angle between the center line P2 of the vacuum hole 122 and the center line P1 of the mercury outlet hole 121 is 5° to 8°. In a specific embodiment, the included angle between the two is set to 6°, but it is not limited to this angle.

[0034] Combined with Figures 1-3As shown, in the projection plane perpendicular to the top surface of the probe body 110, the vertical distance L between the center of the vacuum hole 122 and the center of the mercury outlet hole 121 is 0.9 mm to 1.25 mm. Specifically, there is a notch 111 on the side wall of the front surface of the probe body 110. In the projection plane facing this notch 111, the vertical distance L between the center of the vacuum hole 122 and the center of the mercury outlet hole 121 is 0.9 mm to 1.25 mm, as Figure 3 shown. In a specific embodiment, the vertical distance between the two is preferably set to 1.04 mm. Of course, it is not limited to the setting method in this embodiment.

[0035] Combined again with Figures 1-2 shown, in the present utility model, a plurality of mounting holes 140 are also provided on the probe body 110. Each mounting hole 140 is arranged around the outer periphery of the support column 130 and is evenly distributed around the boss 120. In a specific embodiment, four mounting holes 140 are provided, and the four mounting holes 140 are equally divided and distributed around the boss 120, that is, the central angle between the centers of any two adjacent mounting holes 140 is 90°. The mounting holes 140 are used to detachably mount the probe body 110 on the test platform. For example, the probe body 110 is locked to the test platform by using screws. When it is necessary to replace or maintain the probe, the screws are removed, and the probe can be removed from the test platform. Of course, it is not limited to locking the probe body 110 by screws.

[0036] Refer to Figure 2 shown. In an embodiment of the present utility model, each mounting hole 140 is preferably a stepped hole, and the radius R2 of the inner circle of the mounting hole 140 is preferably set to 1.5 mm, and the radius R3 of the outer circle of the mounting hole 140 is preferably set to 2.85 mm. Of course, the size of the mounting hole 140 is not limited to that in this embodiment.

[0037] Combined again with Figures 2-3 shown. In an embodiment of the present utility model, the radius R4 of the probe body 110 is preferably set to 12.7 mm, that is, the diameter of the probe body 110 is preferably 25.4 mm, and the height H2 of the probe body 110 is preferably 6.5 mm. Thus, 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 this embodiment.

[0038] Combined again with Figures 1-4As shown, in the present utility model, the test probe 100 is preferably integrally formed of polyetheretherketones (PEEK). The 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 detection results. Of course, the test probe 100 can also be formed of other materials.

[0039] In summary, due to the test probe 100 with a reduced contact area in the present utility model, a plurality of struts 130 are arranged around the boss 120 on the probe body 110, and the height of each strut 130 is the same as that of the boss 120. The plurality of struts 130 with a smaller diameter are used to assist in supporting the wafer, thereby reducing the area of the boss 120, so that the contact area between the probe 100 and the wafer is greatly reduced as a whole, effectively reducing the probability of wafer crushing. At the same time, since the contact area of the probe 100 is small, when the probe 100 has a puncture, the vacuum ring will be damaged and mercury cannot be discharged normally, so the state of the probe 100 can be known, and then it can be ensured that the crushing can be detected and PMed in time, reducing the crushing and thus reducing the manufacturing cost, and reducing the repeated cleaning and repeated detection to improve the production capacity of the SiC epitaxial production line, and also reducing the preparation risk of downstream power devices.

[0040] The structures of other parts of the carrier concentration test equipment involved in the present utility model are all conventional structures well known to those of ordinary skill in the art, and will not be described in detail here.

[0041] The above-disclosed are only the preferred embodiments of the present utility model. Of course, the scope of the rights of the present utility model cannot be limited thereby. Therefore, equivalent changes made according to the scope of the patent application of the present utility model still fall within the scope covered by the present utility model.

Claims

1. A test probe for reducing the contact area, characterized in that, Comprising: Probe body; Boss, the boss is arranged at the center of the probe body, a mercury outlet hole penetrating up and down is provided at the center of the boss, and a vacuum hole penetrating up and down is also provided on the boss; A plurality of struts, each strut protrudes from the probe body and is arranged equidistantly around the boss, and the height of each strut is the same as the height of the boss.

2. The test probe for reducing the contact area according to claim 1, wherein The strut is cylindrical.

3. The test probe for reducing the contact area according to claim 1, characterized in that, The diameter of the strut is less than or equal to 1.0 mm.

4. The test probe for reducing the contact area according to claim 1, characterized in that The heights of the strut and the boss are both less than or equal to 0.9 mm, and the radius of the boss is less than or equal to 2 mm.

5. The test probe for reducing the contact area according to any one of claims 1-4, characterized in that, Three of the struts are arranged equidistantly around the boss.

6. The test probe for reducing the contact area according to any one of claims 1-4, characterized in that, A ring groove surrounding the mercury outlet hole is recessed on the boss, and the vacuum hole penetrates the bottom surface of the ring groove.

7. The test probe for reducing the contact area according to claim 6, wherein The width of the ring groove is 0.4 mm to 0.5 mm, and the radius of the mercury outlet hole is 0.8 mm to 1.0 mm.

8. The test probe for reducing the contact area according to claim 1, characterized in that, The vacuum hole and the mercury outlet hole both penetrate the bottom of the probe body, and the vacuum hole is inclined relative to the mercury outlet hole.

9. The test probe for reducing the contact area according to claim 8, wherein, The included angle between the center line of the vacuum hole and the center line of the mercury outlet hole is 5° to 8°.

10. The test probe for reducing the contact area according to any one of claims 1-4, 8-9, characterized in that, A plurality of mounting holes are also provided on the probe body, and each mounting hole is arranged outside the strut and is evenly distributed around the boss.

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