Inspection device, inspection method of semiconductor substrate, manufacturing method of semiconductor substrate, and manufacturing method of semiconductor device

Abstract

The invention relates to an inspection device, an inspection method for a semiconductor substrate, a manufacturing method for a semiconductor substrate, and a manufacturing method for a semiconductor device. An inspection device suitable for inspecting whether a semiconductor substrate has a through hole is provided. The inspection device inspects a semiconductor substrate, and comprises a workbench, a first ring, and a second ring. A first recess is provided on the upper surface of the workbench, and the first recess has a ring-shaped shape when viewed from above. The first ring is an elastic body, and the first ring is arranged in the first recess. The second ring presses the first ring in the direction of the inner side of the ring-shaped shape and presses the first ring against the inner side of the side of the first recess. Compared with the upper surface of the workbench, the first ring protrudes to the upper side. An exhaust hole is provided on the workbench, and the exhaust hole has an opening in the area surrounded by the first recess when viewed from above on the upper surface of the workbench. The semiconductor substrate placed on the first ring is vacuum-adsorbed by exhaust through the exhaust hole.

Description

Technical Field

[0001] The present invention relates to an inspection device, an inspection method for a semiconductor substrate, a manufacturing method for a semiconductor substrate, and a manufacturing method for a semiconductor device. Background Art

[0002] Patent Document 1 discloses a method for manufacturing a semiconductor device using a semiconductor substrate.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2009-206417

[0004] A semiconductor substrate may have a hole that passes through from the surface of the semiconductor substrate to the back surface, i.e., a through hole. If a semiconductor device is manufactured using a semiconductor substrate having a through hole, problems may arise in the process of manufacturing the semiconductor device, resulting in a decrease in productivity. Therefore, it is preferable to inspect whether the semiconductor substrate has a through hole. However, currently known devices are not suitable for inspecting whether the semiconductor substrate has a through hole. Summary of the invention

[0005] The present invention is made to solve such a problem, and an object of the present invention is to provide an inspection device suitable for inspecting whether a semiconductor substrate has a through hole.

[0006] The inspection device of the present invention inspects a semiconductor substrate, and the inspection device comprises: a workbench; a first ring; and a second ring, wherein a first recess is provided on the upper surface of the workbench, the first recess has an annular shape when viewed from above, the first ring is an elastic body, the first ring is arranged in the first recess, the second ring presses the first ring in the direction of the inner side of the annular shape, and presses the first ring against the inner side of the side of the first recess, the first ring protrudes to the upper side compared with the upper surface of the workbench, an exhaust hole is provided on the workbench, the exhaust hole has an opening in the area surrounded by the first recess when viewed from above in the upper surface of the workbench, and the semiconductor substrate placed on the first ring is vacuum adsorbed by exhaust through the exhaust hole.

[0007] Effects of the Invention

[0008] According to the present invention, there is provided an inspection device suitable for inspecting whether a semiconductor substrate has a through hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a diagram showing an inspection unit of the inspection device according to the first embodiment.

[0010] Figure 2 This is a diagram showing an inspection unit of the inspection device according to the first embodiment.

[0011] Figure 3 This is a diagram showing an inspection table of the inspection device according to the first embodiment.

[0012] Figure 4 This is a diagram showing a loop of the inspection device according to the first embodiment.

[0013] Figure 5 This is a diagram showing a loop of the inspection device according to the first embodiment.

[0014] Figure 6 This is a diagram showing an inspection table of the inspection device according to the first embodiment.

[0015] Figure 7 This is a diagram showing the relationship between the height difference of the semiconductor substrate and the degree of leakage of the outside air during inspection using the inspection apparatus according to the first embodiment.

[0016] Figure 8 This is a flowchart showing the method for manufacturing the semiconductor device according to the first embodiment.

[0017] Fig. 9 This is a flowchart showing the inspection method of the first embodiment.

[0018] Fig.10 This is a diagram schematically showing the transition of pressure in the inspection method according to the first embodiment.

[0019] Fig.11 This is a diagram showing an inspection unit and a substrate guide unit of the inspection device according to the first embodiment.

[0020] Fig.12 This is a diagram showing an inspection unit and a substrate guide unit of the inspection device according to the first embodiment.

[0021] Fig.13 This is a diagram showing an inspection unit and a substrate guide unit of the inspection device according to the first embodiment.

[0022] Fig.14 This is a diagram showing an inspection unit and a substrate guide unit of the inspection device according to the first embodiment.

[0023] Fig.15 This is a diagram showing an inspection device according to the first embodiment.

[0024] Fig.16 This is a diagram showing an inspection unit of an inspection device according to a second embodiment.

[0025] Fig.17 This is a diagram showing an inspection unit of an inspection device according to a second embodiment.

[0026] Fig.18 This is a diagram showing an inspection unit of an inspection device according to a third embodiment.

[0027] Fig.19 This is a diagram showing an inspection unit of an inspection device according to a third embodiment.

[0028] Fig. 20 This is a diagram showing an example of a semiconductor device manufactured by the method for manufacturing a semiconductor device according to the first embodiment.

[0029] Fig.21 This is a diagram for explaining the method for manufacturing the semiconductor device according to the first embodiment.

[0030] Fig. 22 This is a diagram for explaining the method for manufacturing the semiconductor device according to the first embodiment. DETAILED DESCRIPTION

[0031] In the following description, up and down are shown with one direction of the inspection device, semiconductor substrate or semiconductor device as the up direction and the opposite direction as the down direction, and do not limit the up and down directions of the inspection device, semiconductor substrate or semiconductor device during manufacturing or use.

[0032] <A. Implementation method 1>

[0033] <A-1. Structure>

[0034] Fig.15 It is a schematic diagram showing the inspection device 101 of this embodiment.

[0035] The inspection device 101 includes a substrate container 13 , a transport hand 14 , an aligner 15 , a vacuum pump 17 , a substrate guide 9 , and an inspection unit 41 .

[0036] Figure 1 It is a top view of the inspection unit 41 . Figure 2 yes Figure 1 A cross-sectional view of the inspection portion 41 taken along line AA. Figure 1 and Figure 2 Also shown in FIG. 4 is a semiconductor substrate 6 which is an object to be inspected by the inspection unit 41 .

[0037] like Figure 1 and Figure 2 As shown, the inspection unit 41 has an inspection table 1, an O-ring 2 (an example of the first ring), a ring 3 (an example of the second ring), a plate 4 (an example of the first plate), a porous plate 5 (an example of the second plate), a screw 8, a vacuum gauge 11 and a valve 12.

[0038] Figure 3 yes Figure 1 The cross-sectional view of the inspection table 1 at the AA line is a cross-sectional view of the inspection table 1 from Figure 2 The figure is extracted and shown. Figure 3As shown, a recess 1c (an example of a first recess) is provided on the upper surface of the inspection table 1. The recess 1c has a ring shape when viewed from above. The recess 1c is provided at a corner between the upper surface and the side surface of the inspection table 1.

[0039] The O-ring 2 is an elastic ring and is arranged in the recessed portion 1c so as to surround the recessed portion 1c in an annular shape.

[0040] The ring 3 is attached to the side surface of the inspection table 1 by screws 8. When the ring 3 is attached to the inspection table 1, the ring 3 and the side surface 1d inside the recess 1c of the inspection table 1 (see Figure 3 ) is smaller than the wire diameter of the O-ring 2. The inner side is the center direction side of the annular shape of the recessed portion 1c when viewed from above.

[0041] The ring 3 presses the O-ring 2 inward and presses the O-ring 2 against the inner side surface 1d of the side surfaces of the recess 1c. That is, the O-ring 2 is pressed and compressed from both the inner side surface 1d of the recess 1c and the ring 3.

[0042] The upper end of the O-ring 2 disposed in the recess 1c protrudes upward compared to the upper surface of the inspection table 1. The upper end of the O-ring 2 disposed in the recess 1c protrudes to the upper side than the upper surface of the inspection table 1 at least in a state where the ring 3 is pressed against the side surface 1d of the inspection table 1. In a state where the O-ring 2 disposed in the recess 1c is in contact with the bottom surface of the recess 1c, the depth of the recess 1c is such a depth that the upper end of the O-ring 2 protrudes upward compared to the upper surface of the inspection table 1. The depth of the recess 1c is, for example, smaller than the wire diameter of the O-ring 2.

[0043] The semiconductor substrate 6 is placed on the O-ring 2 arranged in the recessed portion 1 c.

[0044] The inspection table 1 is provided with an exhaust hole 1 e. The exhaust hole 1 e has an opening 1 a in a region surrounded by the recess 1 c in a plan view of the upper surface of the inspection table 1. The exhaust hole 1 e is connected to a pipe 1 f. The pipe 1 f is connected to a vacuum pump 17.

[0045] A valve 12 is provided between the exhaust hole 1e and the vacuum pump 17 in the pipe 1f.

[0046] A vacuum gauge 11 is connected to the pipe 1 f between the exhaust hole 1 e and the valve 12 .

[0047] When the valve 12 is in a closed state, the space Sp surrounded by the semiconductor substrate 6, the O-ring 2, the inspection table 1, and the valve 12 is a highly airtight space. The vacuum gauge 11 is a pressure gauge for measuring the vacuum degree of the space Sp.

[0048] The vacuum pump 17 is operated to evacuate the space Sp by exhausting air through the exhaust hole 1 e. By evacuating the space Sp, the inspection table 1 vacuum-suctions the semiconductor substrate 6 placed on the O-ring 2 .

[0049] When the semiconductor substrate 6 has a through hole, the vacuum degree of the space Sp deteriorates due to leakage through the through hole. Therefore, the presence or absence of the through hole in the semiconductor substrate 6 can be checked by detecting the deterioration of the vacuum degree of the space Sp with a vacuum gauge.

[0050] In order to improve the sensitivity of the inspection of the presence or absence of through-holes in the semiconductor substrate 6 , the airtightness of the space Sp is preferably high. That is, it is preferred that the leakage of the outside air into the space Sp is small except for the through-holes in the semiconductor substrate 6 .

[0051] If the volume of the space Sp is small, even if the same amount of outside air leaks, the degree of vacuum deterioration is large, so the deterioration of the vacuum degree is easy to detect. Therefore, in order to improve the sensitivity of the inspection of the presence or absence of through holes in the semiconductor substrate 6, the volume of the space Sp is preferably small.

[0052] The O-ring 2 on which the semiconductor substrate 6 is placed is an elastic body, thereby preventing the outside air from passing through between the semiconductor substrate 6 and the O-ring 2 and leaking into the space Sp, thereby improving the airtightness of the space Sp.

[0053] The ring 3 presses the O-ring 2 against the side surface 1 d inside the recess 1 c of the inspection table 1 , thereby preventing outside air from leaking into the space Sp through between the O-ring 2 and the inspection table 1 , thereby improving the airtightness of the space Sp.

[0054] The O-ring 2 is pressed against the side surface 1 d inside the recess 1 c of the inspection table 1 by the ring 3 , thereby suppressing swelling of the O-ring 2 when the inspected semiconductor substrate 6 is removed.

[0055] The side surface 1d inside the recessed portion 1c is inclined so as to be located further outward on the upper side. Thus, swelling of the O-ring 2 when the semiconductor substrate 6 is removed is suppressed.

[0056] Figure 4 is a side view of ring 3. Figure 5 is a top view of ring 3. Figure 4 and Figure 5 The arrangement of the screws 8 is also shown.

[0057] The inner peripheral surface 3a of the ring 3 has a projection 3b projecting inward at the upper end portion, thereby suppressing swelling of the O-ring 2 during detachment.

[0058] By suppressing the swelling of the O-ring 2 when the semiconductor substrate 6 is detached, a decrease in the airtightness of the space Sp is suppressed, and a decrease in the detection sensitivity during the next inspection is suppressed.

[0059] like Figure 1 and Figure 2 As shown, the plate 4 is arranged on the upper surface of the inspection table 1 and is formed by a recess 1c (see Figure 3 The porous plate 5 is arranged on the plate 4.

[0060] A recess 1b (an example of a second recess) is provided in a region surrounded by the recess 1c in a plan view on the upper surface of the inspection table 1. The plate 4 is arranged in the recess 1b.

[0061] Holes 4a, 4b, 4c and 4d are provided in the plate 4. The plate 4 is provided in the recess 1b so that the holes 4a, 4b, 4c and 4d at least partially overlap with the opening 1a of the exhaust hole 1e.

[0062] The plate 4 only needs to have at least one hole that passes through from the upper surface to the lower surface, and it only needs to be arranged in a manner that at least one of the at least one hole overlaps with the opening 1a of the exhaust hole 1e. The gas between the upper surface of the inspection table 1 and the semiconductor substrate 6 passes through the porous plate 5 and at least one of the at least one hole of the plate 4, and then is exhausted through the exhaust hole 1e.

[0063] When the semiconductor substrate 6 placed on the O-ring 2 is vacuum-adsorbed by exhaust through the exhaust hole 1e, the portion of the semiconductor substrate 6 that is located inside the O-ring 2 when viewed from above is pulled toward the inspection table 1, and the semiconductor substrate 6 is deformed. The center portion of the semiconductor substrate 6 is supported by the plate 4 and the porous plate 5, thereby suppressing the deformation of the semiconductor substrate 6 when the space Sp is evacuated. For example, by adjusting the thickness of the plate 4 and the porous plate 5, the deformation amount of the semiconductor substrate 6 when the space Sp is evacuated can be adjusted.

[0064] Depending on the deformation amount of the semiconductor substrate 6 when the space Sp is evacuated, the adhesion between the substrate and the O-ring 2 and the adhesion between the O-ring 2 and the inspection stage change, and the airtightness of the space Sp changes. Figure 7 The relationship between the height difference h of the semiconductor substrate 6 and the pressure difference of the space Sp when the space Sp is evacuated is shown.

[0065] The height difference h indicates how much the height of the upper surface of the semiconductor substrate 6 at the position of the O-ring 2 is higher than the height of the upper surface of the semiconductor substrate 6 at the center of the annular shape of the recess 1c when the space Sp is evacuated (see Figure 6 ).exist Figure 6 In the figure, the positions for measuring the height difference h are indicated by arrows.

[0066] The pressure difference of the space Sp is the difference between the pressure of the space Sp measured in step S306 of the inspection method described in <A-2. Inspection method and manufacturing method> and the pressure of the space Sp measured in step S308 , and indicates the extent of leakage of outside air into the space Sp between step S306 and step S308 . Figure 7 The results shown are obtained by changing the structures of the plate 4 and the porous plate 5 to change the height difference h. In each measurement, other conditions of the structure of the plate 4 and the porous plate 5 are the same.

[0067] like Figure 7 As shown, when the height difference h is greater than or equal to 0.1 mm and less than or equal to 0.9 mm, the pressure difference in the space Sp becomes lower. That is, by setting the height difference h to be greater than or equal to 0.1 mm and less than or equal to 0.9 mm, the leakage caused by the structure of the inspection table 1 is reduced, and the sensitivity of detecting the through hole of the semiconductor substrate 6 is improved.

[0068] In order to set the height difference h to be greater than or equal to 0.1 mm and less than or equal to 0.9 mm, for example, when the space Sp is not evacuated, the height of the upper end of the O-ring 2 arranged in the recess 1c is greater than or equal to 0.1 mm and less than or equal to 0.9 mm than the height of the center of the annular shape of the recess 1c on the upper surface of the porous plate 5 arranged on the plate 4 arranged on the upper surface of the inspection table 1.

[0069] The plate 4 is, for example, an elastic body. If the plate 4 is an elastic body, the semiconductor substrate 6 becomes a state of overall curvature including the vicinity of the center when the space Sp is evacuated, so that the deformation of the semiconductor substrate 6 can be suppressed from being concentrated near the O-ring 2. Therefore, the deformation of the semiconductor substrate 6 near the O-ring 2 is alleviated, the decrease in the adhesion between the O-ring 2 and the semiconductor substrate 6 is suppressed, and the decrease in the detection sensitivity of the through hole is suppressed.

[0070] The plate 4 may have a structure in which the upper surface is curved and the upper surface is concave due to the curvature. As a result, when the space Sp is evacuated, the semiconductor substrate 6 is in a state of being curved as a whole including the vicinity of the center, and thus, it is possible to suppress the deformation of the semiconductor substrate 6 from being concentrated near the O-ring 2. Therefore, the deformation of the semiconductor substrate 6 near the O-ring 2 is alleviated, the decrease in the adhesion between the O-ring 2 and the semiconductor substrate 6 is suppressed, and the decrease in the detection sensitivity of the through hole is suppressed.

[0071] Fig.15The substrate container 13 shown is a container for accommodating the semiconductor substrate 6 .

[0072] The transport hand 14 is used to transport the semiconductor substrate 6 .

[0073] The substrate guide portion 9 is as follows Figures 11 to 14 As shown, the substrate guide 9 is arranged around the inspection table 1. The substrate guide 9 is used, for example, when the semiconductor substrate 6 is placed on the inspection table 1 or when the semiconductor substrate 6 is removed from the inspection table 1.

[0074] The aligner 15 is used to adjust the orientation and position of the semiconductor substrate 6 when the semiconductor substrate 6 is placed on the inspection unit 41. For example, the semiconductor substrate 6 is taken out from the substrate container 13 using the carrier 14, and the semiconductor substrate 6 is placed on the aligner 15, and the orientation and position of the semiconductor substrate 6 are adjusted by the aligner 15. Then, the semiconductor substrate 6 is transferred from the aligner 15 to the substrate guide 9 by the carrier 14. The carrier 14 carrying the semiconductor substrate 6 is dropped from above the substrate guide 9 through the gap 9a, so that the semiconductor substrate 6 is placed on the substrate guide 9. The anti-dislocation pins 10 are arranged on the upper surface of the substrate guide 9, and the position of the semiconductor substrate 6 is restricted by the anti-dislocation pins 10.

[0075] like Fig.11 and Fig.12 As shown in FIG. 1 , after the semiconductor substrate 6 is placed on the substrate guide 9, the substrate guide 9 is lowered, so that Fig.13 and Fig.14 As shown, the semiconductor substrate 6 is placed on the inspection section 41. After the inspection, the substrate guide 9 rises, and the semiconductor substrate 6 is placed on the substrate guide 9. The semiconductor substrate 6 placed on the substrate guide 9 is picked up by the carrier 14. Then, the semiconductor substrate 6 is recovered by, for example, the substrate container 13. By configuring the inspection device 101 as described above, it is possible to automate the inspection of whether or not there is a through hole in the semiconductor substrate 6. In addition, the inspection can be performed while suppressing contact with the surface of the semiconductor substrate 6.

[0076] Fig. 20 This is a cross-sectional view of a semiconductor element 200 , which is an example of a semiconductor device manufactured by the method for manufacturing a semiconductor device of the present embodiment. The semiconductor element 200 is a Schottky barrier diode.

[0077] The semiconductor element 200 has a SiC substrate 71 in the active portion 91, a SiC drift layer 72 formed on the upper surface of the SiC substrate 71, a Ni layer 79 formed on the lower side of the SiC substrate 71, a Ni silicide layer 80 formed at the interface between the SiC substrate 71 and the Ni layer 79, an Au layer 83 formed on the lower surface of the Ni layer 79, a Ti layer 81 formed on the upper surface of the SiC drift layer 72, and an Al layer 82 formed on the Ti layer 81.

[0078] The guard ring 78 is formed at the terminal portion 92 located at a position different from the active portion 91 in the plan view of the semiconductor element 200. The Ti layer 81 is formed across the upper surface of the guard ring 78 and the upper surface of the SiC drift layer 72. The terminal portion 92 is formed so as to surround the active portion 91 in the plan view, for example.

[0079] <A-2. Inspection method and manufacturing method>

[0080] Figure 8 1 is a flowchart showing a method for manufacturing a semiconductor device according to the present embodiment.

[0081] First, in step S1, a semiconductor substrate 60 (see Fig.21 Next, in step S2, an epitaxial layer 61 is formed on the semiconductor substrate 60 by epitaxial growth (see Fig. 22 ). A semiconductor substrate 60 on which an epitaxial layer 61 is formed is referred to as a semiconductor substrate 6.

[0082] Next, the semiconductor substrate 6 is inspected (step S3). Step S3 corresponds to the semiconductor substrate inspection method of the present embodiment. Step S3 will be described in detail later.

[0083] When it is determined in step S3 that the through hole exists in the semiconductor substrate 6 (step S4 : Yes), the semiconductor substrate 6 is removed from the manufacturing process and the semiconductor substrate 6 is not subjected to the subsequent manufacturing process (step S5 ).

[0084] When it is determined in step S3 that there is no through hole in the semiconductor substrate 6 (step S4: No), a wafer process is performed to form a semiconductor element on the semiconductor substrate 6 (step S6). The semiconductor element formed on the semiconductor substrate 6 has, for example, an active portion and an end portion. In this case, in step S6, the active portion and the end portion are formed separately on the semiconductor substrate 6.

[0085] Then, by dicing in step S7 , individual semiconductor elements are obtained.

[0086] The semiconductor element formed on the semiconductor substrate 6 in step S6 is, for example, the semiconductor element 200 described above (see Fig. 20 In this case, the SiC substrate 71 of the semiconductor element 200 corresponds to the semiconductor substrate 60 , and the SiC drift layer 72 of the semiconductor element 200 corresponds to the epitaxial layer 61 .

[0087] The semiconductor element formed on the semiconductor substrate 6 in step S6 may be, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a PN diode, an IGBT (Insulated Gate Bipolar Transistor) or a RC-IGBT (Reverse-Conducting IGBT).

[0088] In step S6, if the semiconductor substrate 6 with through holes is subjected to wafer processing, various problems may occur in each process in the wafer processing, and stable production cannot be performed. For example, poor drying may occur in the cleaning process, and leakage of the resist or developer may occur in the photolithography process. In addition, these poor drying and leakage may cause contamination of equipment in subsequent processes, etc. Moreover, process defects may be caused by leakage of heat-conducting gas in the vacuum process equipment. By performing the inspection of step S3 before the wafer processing, for example, the semiconductor substrate 6 with through holes is removed in advance as in step S5, the occurrence of the above-mentioned problems in the wafer processing can be suppressed, thereby improving productivity.

[0089] The semiconductor substrate 6 is, for example, a silicon carbide substrate. As a switching element that achieves high withstand voltage, low loss and high heat resistance, a semiconductor element using a silicon carbide substrate is being developed. The application of semiconductor elements using silicon carbide substrates to power semiconductor devices such as inverters is constantly expanding. The crystal growth technology of silicon carbide is in the process of development, and there are a large number of crystal defects in the silicon carbide substrate. One of the defects formed in the silicon carbide substrate is a screw dislocation with a hollow structure. The screw dislocation with a hollow structure is called a micropipe. Depending on the situation, the hollow structure is a structure with a through hole that penetrates from the upper surface of the substrate to the lower surface.

[0090] In the above description, when it is determined that there is a through hole in the semiconductor substrate 6, the semiconductor substrate 6 is removed from the manufacturing process in step S5, and the subsequent manufacturing process is not performed on the semiconductor substrate 6. However, the subsequent manufacturing process may also be performed when it is determined that there is a through hole in the semiconductor substrate 6. When it is determined that there is a through hole, for example, the subsequent manufacturing process is performed by a method different from the case where it is determined that there is no through hole.

[0091] Figure 8 The portion other than step S6 and step S7 in the flowchart corresponds to the semiconductor substrate manufacturing method of the present embodiment. In the semiconductor substrate manufacturing method, semiconductor substrates judged to have through holes can be eliminated and only semiconductor substrates judged to have no through holes can be processed as finished products, or each semiconductor substrate can be processed as a finished product of different quality according to the presence or absence of through holes.

[0092] The method of checking in step S3 will be described. Fig. 9 It is a flowchart showing the details of step S3. Fig.10 Schematically shows the change of the pressure of the space Sp in step S3. Fig.10 In FIG. 1 , the pressure change in the case of a through hole is shown by a dotted line, and the pressure change in the case of no through hole is shown by a solid line. The pressure change before time t2 is also different in the case of a through hole and the case of no through hole, but Fig.10 The difference before time t2 between the case with the through hole and the case without the through hole is omitted.

[0093] First, in step S301, the semiconductor substrate 6 is placed on the inspection table 1. The semiconductor substrate 6 is placed on the O-ring 2 disposed in the recess 1c. The O-ring 2 is pressed inwardly by the ring 3 and pressed against the inner side surface of the recess 1c.

[0094] After step S301, the vacuum pump 17 is turned on (step S302). Next, at time t1, the valve 12 is opened (step S303). Thus, the space Sp is exhausted through the exhaust hole 1e, and the semiconductor substrate 6 is vacuum-adsorbed.

[0095] Next, after confirming that the pressure of the space Sp has dropped to less than or equal to the set pressure (step S304), the valve 12 is set to a closed state at time t2 (step S305). The set pressure can be less than or equal to the atmospheric pressure, but in order to improve the sensitivity of the inspection, it is preferably as small as possible. In this embodiment, the set pressure is set to 0.1 Pa.

[0096] After the valve 12 is closed in step S305, the pressure is measured at time t3 after the time required for the pressure to stabilize (step S306). Then, a predetermined time is waited (step S307), and the pressure is measured again at time t4 (step S308).

[0097] Then, the presence or absence of a through hole is determined based on the pressure measured in step S306 and step S308 (step S309). For example, the difference p1-p0 between p1 and p0 is compared with a predetermined threshold value p th Compare, if p1-p0 is greater than p th , that is, p1 is greater than p0+p th , it is judged that there is a through hole, otherwise it is judged that there is no through hole. Fig.10 In FIG. 1 , as an example, when a through hole exists in the semiconductor substrate 6 , pressures p0 and p1 measured in step S306 and step S308 , respectively, are shown.

[0098] After step S309 , in step S310 , the space Sp is opened to the atmosphere so that the semiconductor substrate 6 is not vacuum-adsorbed by the inspection stage 1 , and in step S311 , the semiconductor substrate 6 is removed from the inspection section 41 .

[0099] After the above steps, the inspection is completed.

[0100] In the above description, in S306 and S308, the pressure is measured, and the difference in pressure between the two measurements is used to determine whether there is a through hole, but the method for determining whether there is a through hole is not limited to such a method, as long as it is a method that can measure the degree of leakage of external air to the space Sp. For example, instead of measuring the time t3, it is also possible to measure the magnitude of the pressure at time t4, and determine whether there is a through hole based on the magnitude of the pressure in the space Sp at time t4. In addition, more generally, it is also possible to determine whether there is a through hole based on the change in the pressure of the space Sp.

[0101] Although the determination of the presence of through holes is described in step S309, more generally, the quality of the semiconductor substrate 6 may be determined. The quality of the semiconductor substrate 6 is based on, for example, the presence of through holes, the number of through holes, or the size of through holes.

[0102] <B. Implementation method 2>

[0103] The inspection device of the second embodiment is different from the inspection device 101 of the first embodiment in that an inspection unit 42 is provided instead of the inspection unit 41. The inspection device of the second embodiment is the same as the inspection device 101 of the first embodiment in other respects.

[0104] Fig.16 It is a plan view showing the inspection unit 42 . Fig.17 yes Fig.16 BB line is a cross-sectional view of the inspection portion 42.

[0105] The inspection unit 42 is different from the inspection unit 41 of the inspection device 101 of the first embodiment in that the inspection table 1 has a vent hole 7. The inspection unit 42 is the same as the inspection unit 41 of the inspection device 101 of the first embodiment in other aspects. The vent hole 7 is a concave portion 1c (see Figure 3 ) is a vent connected to the space Sp.

[0106] The vent hole 7 allows the area surrounded by the side and bottom of the recess 1c of the inspection table 1 and the O-ring 2 to be evacuated in advance, so that no air is trapped, thereby suppressing the deterioration of the vacuum degree during inspection. In addition, since the area is evacuated, the O-ring 2 is attracted inward, thereby improving the adhesion between the O-ring 2 and the inspection table 1, and suppressing the leakage of external air into the space Sp through the space between the O-ring 2 and the inspection table 1. Fig.16 Although the case where four ventilation holes 7 are present is shown in FIG. 1 , the number of ventilation holes 7 only needs to be one or more.

[0107] <C. Implementation method 3>

[0108] The inspection device of the third embodiment is different from the inspection device of the second embodiment in that an inspection unit 43 is provided instead of the inspection unit 42. The inspection device of the third embodiment is the same as the inspection device of the second embodiment in other respects.

[0109] Fig.18 It is a diagram showing the inspection unit 43 . Fig.19 yes Fig.18 4 is a cross-sectional view of the inspection portion 43 taken along line CC.

[0110] At the inspection portion 43, the upper surface of the inspection table 1 is formed between the recessed portion 1b and the recessed portion 1c (see Figure 3 ) are inclined so that the concave portion 1c side is higher and the concave portion 1b side is lower. The other aspects of the inspection unit 43 are the same as the inspection unit 42 of the inspection device of the second embodiment.

[0111] The upper surface of the inspection table 1 is inclined between the recessed portion 1b and the recessed portion 1c so that the recessed portion 1c side is higher and the recessed portion 1b side is lower, thereby preventing the semiconductor substrate 6 from being deformed or coming into contact with the inspection table 1 due to the vacuuming of the space Sp. Therefore, it is possible to prevent the adhesion between the semiconductor substrate 6 and the O-ring 2 from being reduced, and to prevent external air from leaking into the space Sp through the space between the semiconductor substrate 6 and the O-ring 2.

[0112] The upper surface of the inspection table 1 has an inclination along the semiconductor substrate 6 deformed by the evacuation of the space Sp, thereby suppressing contact between the semiconductor substrate 6 and the upper surface of the inspection table 1 and improving the sensitivity of detecting the through hole by suppressing the volume of the space Sp.

[0113] The inclination between the recessed portion 1 b and the recessed portion 1 c on the upper surface of the inspection table 1 may be a step-like inclination.

[0114] In addition, the various embodiments can be freely combined, and the various embodiments can be appropriately modified or omitted.

[0115] Description of the label

[0116] 1 inspection table, 1a opening, 1b, 1c recessed parts, 1d side, 1e exhaust hole, 1f piping, 2 O-ring, 3 ring, 3a inner circumferential surface, 3b protrusion, 4 plate, 4a, 4b, 4c, 4d holes, 5 porous plate, 6 semiconductor substrate, 7 vent hole, 8 screw, 9 substrate guide part, 9a gap, 10 anti-misalignment pin, 11 vacuum gauge, 12 valve, 13 substrate container, 14 transport hand, 15 aligner, 17 vacuum pump, 41, 42, 43 inspection part, 60 semiconductor substrate, 61 epitaxial layer, 71 SiC substrate, 72 SiC drift layer, 78 guard ring, 79 Ni layer, 80 Ni silicide layer, 81 Ti layer, 82 Al layer, 83 Au layer, 91 active part, 92 terminal part, 101 inspection device, 200 semiconductor element, Sp space.

Claims

1. An inspection device for inspecting a semiconductor substrate. The inspection device has: Workbench; Ring 1; and Ring 2, A first recess is provided on the upper surface of the workbench. The first recess has a ring-shaped shape when viewed from above. The first ring is an elastic body, The first ring is arranged in the first recessed portion, The second ring presses the first ring toward the inner side of the annular shape, and presses the first ring against the inner side surface of the side surfaces of the first recessed portion. The first ring protrudes upward from the upper surface of the workbench. The workbench is provided with an exhaust hole having an opening in a region of the upper surface of the workbench surrounded by the first recessed portion when viewed from above. The semiconductor substrate placed on the first ring is vacuum-adsorbed by exhausting gas through the exhaust hole. The inspection device also has: a first plate disposed in a region of the upper surface of the table that is surrounded by the first recessed portion when viewed from above; and a second plate, which is arranged on the first plate, The second plate is a porous plate. The first plate is an elastic body.

2. An inspection device for inspecting a semiconductor substrate. The inspection device has: Workbench; Ring 1; and Ring 2, A first recess is provided on the upper surface of the workbench. The first recess has a ring-shaped shape when viewed from above. The first ring is an elastic body, The first ring is arranged in the first recessed portion, The second ring presses the first ring toward the inner side of the annular shape, and presses the first ring against the inner side surface of the side surfaces of the first recessed portion. The first ring protrudes upward from the upper surface of the workbench. The workbench is provided with an exhaust hole having an opening in a region of the upper surface of the workbench surrounded by the first recessed portion when viewed from above. The semiconductor substrate placed on the first ring is vacuum-adsorbed by exhausting gas through the exhaust hole. The inspection device also has: a first plate disposed in a region of the upper surface of the table that is surrounded by the first recess when viewed from above; and a second plate, which is arranged on the first plate, The second plate is a porous plate. The upper surface of the first plate is curved, The upper surface of the first plate is recessed due to the bending.

3. The inspection device according to claim 1 or 2, wherein: The first plate has at least one hole extending from the upper surface to the lower surface. The exhaust is performed through at least one of the at least one hole of the first plate and the second plate.

4. The inspection device according to claim 1 or 2, wherein: The upper end of the first ring arranged in the first recess is higher than the center of the annular shape of the first recess on the upper surface of the second plate arranged on the first plate arranged on the upper surface of the workbench by 0.1 mm or more and 0.9 mm or less.

5. An inspection device for inspecting a semiconductor substrate. The inspection device has: Workbench; Ring 1; and Ring 2, A first recess is provided on the upper surface of the workbench. The first recess has a ring-shaped shape when viewed from above. The first ring is an elastic body, The first ring is arranged in the first recessed portion, The second ring presses the first ring toward the inner side of the annular shape, and presses the first ring against the inner side surface of the side surfaces of the first recessed portion. The first ring protrudes upward from the upper surface of the workbench. The workbench is provided with an exhaust hole having an opening in a region of the upper surface of the workbench surrounded by the first recessed portion when viewed from above. The semiconductor substrate placed on the first ring is vacuum-adsorbed by exhausting gas through the exhaust hole. The inspection device also has: a first plate disposed in a region of the upper surface of the table that is surrounded by the first recessed portion when viewed from above; and a second plate, which is arranged on the first plate, The second plate is a porous plate. A second recess is provided on the upper surface of the workbench. The second recess is surrounded by the first recess when viewed from above. The first plate is disposed in the second recess.

6. The inspection device according to claim 5, wherein: The table is provided with a vent hole connecting the first recess and the second recess.

7. The inspection device according to claim 5 or 6, wherein: The upper surface of the table is inclined between the first recessed portion and the second recessed portion so that the first recessed portion side is higher and the second recessed portion side is lower.

8. The inspection device according to any one of claims 1, 2, 5 and 6, wherein: The inner side surface of the side surfaces of the first recessed portion is inclined such that the upper side is located further outward than the lower side.

9. The inspection device according to any one of claims 1, 2, 5 and 6, wherein: It also has a vacuum pump and a pressure gauge. The exhaust is performed by the vacuum pump, The pressure gauge measures the pressure of a region surrounded by the semiconductor substrate, the first ring, and the stage.

10. The inspection device according to any one of claims 1, 2, 5 and 6, wherein: The first ring is an O-ring.

11. A method for inspecting a semiconductor substrate, using the inspection device according to any one of claims 1 to 10, In the semiconductor substrate inspection method, placing a semiconductor substrate on the first ring, The semiconductor substrate placed on the first ring is vacuum-adsorbed by the exhaust while the first ring is pressed inward by the second ring. The pressure of a region surrounded by the semiconductor substrate, the first ring, and the stage is measured.

12. A method for inspecting a semiconductor substrate, wherein an inspection device for inspecting the semiconductor substrate comprises: Workbench; Ring 1; and Ring 2, A first recess is provided on the upper surface of the workbench. The first recess has a ring-shaped shape when viewed from above. The first ring is an elastic body, The first ring is arranged in the first recessed portion, The second ring presses the first ring toward the inner side of the annular shape, and presses the first ring against the inner side surface of the side surfaces of the first recessed portion. The first ring protrudes upward from the upper surface of the workbench. The workbench is provided with an exhaust hole having an opening in a region of the upper surface of the workbench surrounded by the first recessed portion when viewed from above. The semiconductor substrate placed on the first ring is vacuum-adsorbed by exhausting gas through the exhaust hole. In a method for inspecting a semiconductor substrate, placing a semiconductor substrate on the first ring, The semiconductor substrate placed on the first ring is vacuum-adsorbed by the exhaust while the first ring is pressed inward by the second ring. measuring the pressure of the area surrounded by the semiconductor substrate, the first ring, and the worktable, During the measurement, the height of the upper surface of the semiconductor substrate at the position of the first ring is higher than the height of the upper surface of the semiconductor substrate at the center of the ring shape of the first recess by 0.1 mm or more and 0.9 mm or less.

13. The method for inspecting a semiconductor substrate according to claim 11 or 12, wherein: The quality of the semiconductor substrate is determined based on the measurement result.

14. The method for inspecting a semiconductor substrate according to claim 11 or 12, wherein: Based on the measurement result, it is determined whether the semiconductor substrate has a through hole.

15. A method for inspecting a semiconductor substrate, using the inspection device according to any one of claims 1 to 10, In the semiconductor substrate inspection method, placing a semiconductor substrate on the first ring, The semiconductor substrate placed on the first ring is vacuum-adsorbed by the exhaust while the first ring is pressed inward by the second ring. The degree of leakage of external air into a region surrounded by the semiconductor substrate, the first ring, and the stage is measured.

16. A method for inspecting a semiconductor substrate, wherein an inspection device for inspecting the semiconductor substrate comprises: Workbench; Ring 1; and Ring 2, A first recess is provided on the upper surface of the workbench. The first recess has a ring-shaped shape when viewed from above. The first ring is an elastic body, The first ring is arranged in the first recessed portion, The second ring presses the first ring toward the inner side of the annular shape, and presses the first ring against the inner side surface of the side surfaces of the first recessed portion. The first ring protrudes upward from the upper surface of the workbench. The workbench is provided with an exhaust hole having an opening in a region of the upper surface of the workbench surrounded by the first recessed portion when viewed from above. The semiconductor substrate placed on the first ring is vacuum-adsorbed by exhausting gas through the exhaust hole. In a method for inspecting a semiconductor substrate, placing a semiconductor substrate on the first ring, The semiconductor substrate placed on the first ring is vacuum-adsorbed by the exhaust while the first ring is pressed inward by the second ring. measuring the degree of leakage of external air into the area surrounded by the semiconductor substrate, the first ring, and the workbench, During the measurement, the height of the upper surface of the semiconductor substrate at the position of the first ring is higher than the height of the upper surface of the semiconductor substrate at the center of the ring shape of the first recess by 0.1 mm or more and 0.9 mm or less.

17. The method for inspecting a semiconductor substrate according to claim 15 or 16, wherein: The quality of the semiconductor substrate is determined based on the measurement result.

18. The method for inspecting a semiconductor substrate according to claim 15 or 16, wherein: Based on the measurement result, it is determined whether the semiconductor substrate has a through hole.

19. A method for manufacturing a semiconductor substrate, wherein: preparing a semiconductor substrate, The semiconductor substrate is inspected by the semiconductor substrate inspection method according to any one of claims 11 to 18.

20. The method for manufacturing a semiconductor substrate according to claim 19, wherein: forming an epitaxial layer on the semiconductor substrate by epitaxial growth, The inspecting of the semiconductor substrate is performed after the forming of the epitaxial layer.

21. A method for manufacturing a semiconductor device, wherein: A semiconductor substrate manufactured by the method for manufacturing a semiconductor substrate according to claim 19 or 20 is prepared, A semiconductor element is formed on the semiconductor substrate.

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