Semiconductor manufacturing apparatus and method of manufacturing semiconductor device

Abstract

A semiconductor manufacturing apparatus and a manufacturing method of a semiconductor device capable of detecting defects of a wafer are provided. The semiconductor manufacturing apparatus includes a stage having a mounting area of a wafer on an upper surface, a plurality of suction pipes extending through the stage from the mounting area to a back surface side of the stage, a vacuum pump connected to the plurality of suction pipes to suction the wafer to the mounting area via the plurality of suction pipes, a cover provided on the upper surface of the stage to cover the wafer, a gas supply line to pressurize a space surrounded by the upper surface of the stage and the cover, and a pressure sensor to detect pressure in the plurality of suction pipes.

Description

TECHNICAL FIELD

[0001] The present application relates to a semiconductor manufacturing apparatus and a manufacturing method of a semiconductor device. BACKGROUND

[0002] A foreign matter detection method of an adsorption table is disclosed in Patent Literature 1. The adsorption table has a setting portion which adsorbs and fixes a substrate, a pressure measuring unit which measures an adsorption pressure of the substrate at the setting portion, and a determination portion which determines whether or not there is an adsorption abnormality of the substrate. The foreign matter detection method has a measurement process and a determination process. In the measurement process, the pressure measuring unit measures the adsorption pressure of the substrate at the setting surface. In the determination process, the determination portion performs a comparison evaluation of variation data and reference variation data. The variation data is data of the adsorption pressure in a period from the start of the adsorption of the substrate to the time when the value of the adsorption pressure is about to be stabilized, among data of the adsorption pressure obtained in the measurement process. The reference variation data is variation data in the case where there is no foreign matter at the setting surface, which is stored in the determination portion in advance. Thus, the determination portion determines whether or not there is an adsorption abnormality at the setting surface, and determines whether or not there is a foreign matter on the setting surface.

[0003] Patent Literature 1: Japanese Patent Application Laid-Open No. 2013-149809

[0004] The foreign matter detection method shown in Patent Literature 1 is a technology related to the detection of a foreign matter on a work table. Therefore, for a defect of a semiconductor wafer placed on the work table, the variation of the adsorption pressure caused by the defect is too small, and it can be impossible to perform the detection. SUMMARY

[0005] The present application has been made to solve the above problem, and has an object to provide a semiconductor manufacturing apparatus and a manufacturing method of a semiconductor device which can detect a defect of a wafer.

[0006] The semiconductor manufacturing apparatus according to the present application has a work table which has a mounting region of a wafer on an upper surface, a plurality of suction pipes which extend to a back surface side of the work table from the mounting region so as to penetrate the work table, a vacuum pump which is connected to the plurality of suction pipes and adsorbs the wafer to the mounting region via the plurality of suction pipes, a cover which is provided on the upper surface of the work table and covers the wafer, a gas supply line which pressurizes a space surrounded by the upper surface of the work table and the cover, and a pressure sensor which detects a pressure in the plurality of suction pipes.

[0007] The semiconductor device manufacturing method according to the present application is a method of mounting a wafer on a mounting region provided on an upper surface of a stage, mounting a cover on the upper surface of the stage to cover the wafer, supplying a gas to a space surrounded by the upper surface of the stage and the cover, pressurizing the wafer, adsorbing the wafer to the mounting region by a vacuum pump connected to a plurality of suction pipes extending from the mounting region to a back surface side of the stage, detecting a pressure in the plurality of suction pipes while pressurizing the wafer and adsorbing the wafer to the mounting region, and cleaning, film forming, photolithography, etching, diffusion processing, or ion implantation of the wafer after the pressure in the plurality of suction pipes is detected.

[0008] Effects of the Invention

[0009] In the semiconductor manufacturing apparatus and the semiconductor device manufacturing method according to the present application, a gas can be supplied to a space surrounded by an upper surface of a stage and a cover, and a wafer can be pressurized. Therefore, a defect of the wafer can be detected. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a plan view and an elevation view of a semiconductor manufacturing apparatus according to Embodiment 1.

[0011] Figure 2 is a plan view and an elevation view showing a state in which a cover is mounted to the semiconductor manufacturing apparatus according to Embodiment 1.

[0012] Figure 3 is a plan view and an elevation view of a semiconductor manufacturing apparatus according to a modification of Embodiment 1.

[0013] Figure 4 is a plan view and an elevation view of a semiconductor manufacturing apparatus according to Embodiment 2.

[0014] Figure 5 is a view for explaining a semiconductor device inspection method according to Embodiment 2.

[0015] Figure 6 is a flowchart for explaining a semiconductor device manufacturing method according to Embodiment 3. DETAILED DESCRIPTION

[0016] The semiconductor manufacturing apparatus and the semiconductor device manufacturing method according to each of the embodiments will be described with reference to the drawings. The same reference numerals are assigned to the same or corresponding structural elements, and repeated description will be omitted.

[0017] Embodiment 1

[0018] Figure 1Embodiment 1 relates to a plan view and an elevation view of a semiconductor manufacturing apparatus 100. The semiconductor manufacturing apparatus 100 has a table 2 having a mounting region 2a of a wafer 1 on an upper surface. The wafer 1 is a semiconductor substrate. In addition, the semiconductor manufacturing apparatus 100 has a plurality of suction pipes 4 extending from the mounting region 2a to a back surface side of the table 2. Each of the suction pipes 4 has a first portion 4a provided inside the table 2 and a second portion 4b provided outside the table 2 extending from the back surface of the table 2. A vacuum pump 3 is connected to the plurality of suction pipes 4, and the wafer 1 is sucked to the mounting region 2a via the plurality of suction pipes 4. A pressure sensor 5 is provided to each of the suction pipes 4. The pressure sensor 5 detects a pressure in the suction pipe 4.

[0019] The table 2 is virtually divided into a lattice shape, thereby forming a plurality of suction regions 2b. The suction pipe 4 is provided to each of the plurality of suction regions 2b. The suction pipe 4 is connected to the pressure sensor 5. Figure 1 In Embodiment 1, positions of suction ports 4c of the plurality of suction pipes 4 are indicated by dotted lines. The suction ports 4c are arranged in a lattice shape in the mounting region 2a. The vacuum pump 3 performs vacuum suction of the wafer 1 in units of the plurality of suction regions 2b.

[0020] The pressure sensor 5 connected to the suction pipe 4 monitors the pressure for each of the plurality of suction regions 2b. If the wafer 1 having a defect 1a such as a through hole is sucked, a different pressure from that of the suction region 2b without the defect 1a is obtained in the suction region 2b where the defect 1a exists. Thus, by detecting the pressure variation by the pressure sensor 5, the defect can be detected.

[0021] The size of the suction region 2b is determined according to the size of the defect 1a to be detected. For example, in a case where a defect of about 10 μm to 1 cm square is detected in a wafer 1 having a diameter of 8 inches, the suction region 2b can be 1 cm square. In this case, the suction region 2b is about 20 in each column. Therefore, the pressure sensor 5 can be about 400. The number of the pressure sensor 5 can be changed to match the diameter of the wafer 1, for example, 1 column or the entire. For example, if the diameter of the wafer 1 is 4 inches to 12 inches and the suction region 2b is 1 cm square, the pressure sensor 5 can be about 10 to 30 in each column, and about 100 to 900 in total.

[0022] Figure 2is a plan view and a front view showing a state in which the semiconductor manufacturing apparatus 100 according to Embodiment 1 is installed with the cover 6. The semiconductor manufacturing apparatus 100 has the cover 6 which is provided on the upper surface of the table 2 to cover the wafer 1. The cover 6 is box-shaped or dome-shaped. The cover 6 is in close contact with the table 2 in a manner to ensure airtightness of the inside. The cover 6 is connected to the gas supply line 7. The gas supply line 7 pressurizes a space surrounded by the upper surface of the table 2 and the cover 6. The gas supply line 7 supplies, for example, N2into the cover 6.

[0023] The gas enclosed into the cover 6 presses the entire surface of the wafer 1 against the table 2. Therefore, a pressure variation is caused in the suction pipe 4 due to a defect state of the surface of the wafer 1. In a case where the defect is a through-hole, the gas supplied from the gas supply line 7 leaks to the suction pipe 4 via the defect. Thus, a pressure variation is caused in the suction pipe 4. Therefore, it is possible to increase the defect detection sensitivity and to detect defects such as through-holes in the wafer 1. In the present embodiment, even a minute defect of, for example, 10 μm to 1 cm can be detected. As the defects to be detected in the present embodiment, for example, a through-hole such as a microtube, a crack reaching the back surface from the surface of the wafer 1, and the like are assumed.

[0024] The wafer 1 is formed of silicon. It is not limited thereto, and the wafer 1 can be formed of a wide bandgap semiconductor having a larger bandgap than silicon. The wide bandgap semiconductor is, for example, silicon carbide, a gallium nitride-based material, or diamond. In particular, silicon carbide has a plurality of crystal polytypes, and it is difficult to configure a SiC crystal with only one crystal polytype. Silicon carbide is likely to mix other crystal polytypes in crystal growth to become a cause of defects, compared with silicon. Therefore, for example, a through-hole such as a microtube is likely to be generated. Therefore, the present embodiment is particularly effective in a case where the wafer 1 is formed of a wide bandgap semiconductor.

[0025] In addition, silicon or silicon carbide is a transparent material. Therefore, light transmits through the wafer 1, and it is difficult to detect defects by light. In contrast, in the present embodiment, defects are detected by a pressure variation, and therefore even the wafer 1 which transmits light can be detected. In addition, a microtube is usually formed obliquely. Therefore, it is difficult to detect a microtube by light. In contrast, in the present embodiment, the adsorption region 2b is subdivided, and the wafer 1 is vacuum-adsorbed in units of the respective adsorption regions 2b to detect defects. Therefore, it is possible to increase the detection sensitivity of a microtube.

[0026] Figure 3A modification of Embodiment 1 relates to a plan view and an elevation view of a semiconductor manufacturing apparatus 200. As the gas supplied from the gas supply line 7, He can be supplied in addition to N2. Further, the semiconductor manufacturing apparatus 200 can have a concentration meter 205 that detects the concentration of He gas supplied from the gas supply line 7 in the plurality of suction pipes 4. The concentration meter 205 is provided to each suction pipe 4.

[0027] In the case of the semiconductor manufacturing apparatus 200, the concentration of He gas in the suction pipe 4 changes because He gas leaks through the defect. In this way, by using both the pressure sensor 5 and the concentration meter 205, even a small defect that penetrates the wafer 1 can be detected. Further, because He gas is a gas that is normally used for leak testing, it is easy to handle. Here, an example of using both the pressure sensor 5 and the concentration meter 205 is shown, but only the concentration meter 205 can be provided.

[0028] These modifications can be appropriately applied to the semiconductor manufacturing apparatus and the method of manufacturing a semiconductor device that are described in the following embodiments. Further, because there are many points in common with Embodiment 1, the semiconductor manufacturing apparatus and the method of manufacturing a semiconductor device that are described in the following embodiments are described with the differences from Embodiment 1 as the center.

[0029] Embodiment 2

[0030] Figure 4 A plan view and an elevation view of a semiconductor manufacturing apparatus 300 that is related to Embodiment 2 are shown. The semiconductor manufacturing apparatus 300 has one pressure sensor 5. The semiconductor manufacturing apparatus 300 has a plurality of valves 308 that are respectively provided between the plurality of suction pipes 4 and the pressure sensor 5. Each of the plurality of suction areas 2b and the pressure sensor 5 are connected via the valves 308.

[0031] Further, the semiconductor manufacturing apparatus 300 has a detection device 309 that detects whether or not there is a defect in the area of the wafer 1 that is sucked by each of the plurality of suction pipes 4, based on the pressure measured by the pressure sensor 5. The detection device 309 sequentially sets the plurality of valves 308 to an open state, and detects whether or not there is a defect in the area of the wafer 1 that is sucked by the suction pipe 4 corresponding to the valve 308 in the open state, based on the pressure in the suction pipe 4.

[0032] The detection device 309 has, for example, an opening / closing section 309a, a measurement section 309b, a determination section 309c, and an output section 309d. The opening / closing section 309a controls the opening / closing of the valves 308 and sequentially switches the plurality of valves 308 to the open state. The measurement section 309b measures the pressure in the suction pipe 4 corresponding to the valve 308 in the open state. The determination section 309c determines the presence or absence of a defect based on the pressure measured by the measurement section 309b. The output section 309d outputs the determination result of the determination section 309c.

[0033] In the adsorption region 2b corresponding to the valve 308 in the closed state, the wafer 1 is vacuum-adsorbed. In the adsorption region 2b corresponding to the valve 308 in the open state, the wafer 1 is discriminated for the presence or absence of a defect. Thus, the inspection can be performed by one pressure sensor 5. Therefore, space saving and cost reduction can be achieved.

[0034] Similarly, the semiconductor manufacturing device 300 can also have one density meter 205, and each adsorption region 2b is connected to the density meter 205 via the valve 308. In this case, the detection device 309 detects the presence or absence of a defect in the region of the wafer 1 adsorbed by each of the plurality of suction pipes 4 based on the density of the gas measured by the density meter 205. The detection device 309 sequentially sets the plurality of valves 308 to the open state and detects the presence or absence of a defect in the region of the wafer 1 adsorbed by the suction pipe 4 corresponding to the valve 308 in the open state based on the density of the gas in the suction pipe 4. At this time, the measurement section 309b measures the density of the gas in the suction pipe 4 corresponding to the valve 308 in the open state. The determination section 309c determines the presence or absence of a defect based on the density measured by the measurement section 309b.

[0035] Figure 5 is a diagram illustrating a method of inspecting a semiconductor device according to Embodiment 2. In Figure 5 , as indicated by an arrow 81, the detection can also be performed sequentially from the outer peripheral portion to the center of the wafer 1. That is, the detection device 309 can detect the presence or absence of a defect in the outer peripheral portion of the wafer 1 and then detect the presence or absence of a defect in the central portion of the wafer 1. In Figure 5 , the inspection is sequentially performed in the circumferential direction of the wafer 1. A defect is usually easily generated in the outer peripheral portion of the wafer 1. The reason is that physical stress is applied to the outer peripheral portion by contact with a cassette in which the wafer 1 is housed or a device on which the wafer 1 is placed. Therefore, the inspection time can be shortened and the productivity can be improved by performing the inspection from the outer peripheral portion.

[0036] The detection device 309 according to the present embodiment can be provided to the semiconductor manufacturing device 100 or the semiconductor manufacturing device 200 according to Embodiment 1. In this case, the opening / closing section 309a can also be provided.

[0037] Embodiment 3

[0038] Figure 6 is a flowchart illustrating a manufacturing method of a semiconductor device to which Embodiment 3 is applied. In Figure 6 A manufacturing method of a semiconductor device using the semiconductor manufacturing apparatus of Embodiment 1 or 2 is illustrated in FIG. 8. First, as Step S1, a preparation process of preparing a wafer 1 is performed. In the preparation process, for example, a crystal ingot of silicon or silicon carbide is cut into a prescribed thickness to prepare the wafer 1. Further, in Step S1, the wafer 1 can also be prepared by performing epitaxial growth on a cut substrate.

[0039] Next, as Step S2, the wafer 1 is subjected to a product manufacturing process. The product manufacturing process, that is, a manufacturing process of a semiconductor device, includes a cleaning process illustrated in Step S3, a film forming process illustrated in Step S4, a photolithography process illustrated in Step S5, an etching process illustrated in Step S6, and a diffusion, ion implantation process illustrated in Step S7. Further, these processes can apply known manufacturing methods. In addition, the film forming process includes oxidation, CVD (Chemical Vapor Deposition), metallization, and the like.

[0040] Further, in the inspection process using the semiconductor manufacturing apparatus 100, the wafer 1 is mounted on a mounting region 2a provided on the upper surface of the stage 2. Next, the cover 6 is mounted on the upper surface of the stage 2 to cover the wafer 1. Next, a space surrounded by the upper surface of the stage 2 and the cover 6 is supplied with a gas to pressurize the wafer 1. Further, the wafer 1 is adsorbed to the mounting region 2a by the vacuum pump 3. Moreover, while the wafer 1 is pressurized by the gas and adsorbed to the mounting region 2a, the pressure in the plurality of suction pipes 4 is detected. Further, in the case of using the semiconductor manufacturing apparatuses 200, 300, while the wafer 1 is pressurized by the gas and adsorbed to the mounting region 2a, the concentration of the gas in the plurality of suction pipes 4 is detected. Thus, the wafer 1 is inspected for defects.

[0041] In the present embodiment, the inspection process by the semiconductor manufacturing apparatus 100, 200, or 300 is provided before at least one of the cleaning process, the film forming process, the photolithography process, the etching process, and the diffusion, ion implantation process. That is, the pressure or the concentration of the gas in the plurality of suction pipes 4 is detected, and after the inspection, the wafer 1 is subjected to the cleaning, film forming, photolithography, etching, diffusion treatment, or ion implantation. Thus, in the manufacturing process of the semiconductor device, secondary failures such as stage abnormalities that can occur due to the processing of wafers having defects can be suppressed.

[0042] By performing the inspection process before each process, the following effects are obtained, for example. By performing the inspection process before the cleaning process or the photolithography process, corrosion of the table caused by inflow of the chemical liquid from the defect is suppressed. In addition, contamination of the subsequent wafer is suppressed. By performing the inspection process before the film formation process, deposition of the product generated by the film formation on the table through the defect is suppressed. By performing the inspection process before the etching process, corrosion of the table caused by inflow of the etching gas from the defect is suppressed. In addition, contamination of the subsequent wafer is suppressed. By performing the inspection process before the diffusion or ion implantation process, burn of the table caused by irradiation of laser light to the defect at the time of laser annealing treatment or the like is suppressed.

[0043] Furthermore, the technical features described in each embodiment can be appropriately combined and used.

[0044] Explanation of Reference Signs

[0045] 1 wafer, 1a defect, 2 table, 2a mounting region, 2b adsorption region, 3 vacuum pump, 4 suction pipe, 4a first portion, 4b second portion, 4c suction port, 5 pressure sensor, 6 cover, 7 gas supply line, 100, 200 semiconductor manufacturing apparatus, 205 concentration meter, 300 semiconductor manufacturing apparatus, 308 valve, 309 detection apparatus, 309a opening / closing portion, 309b measurement portion, 309c determination portion, 309d output portion

Claims

1. A semiconductor manufacturing apparatus characterized by comprising: has: a table having a mounting region of a wafer on an upper surface; a plurality of suction pipes extending through the table from the mounting region to a back surface side of the table; a vacuum pump connected to the plurality of suction pipes, which sucks the wafer to the mounting region via the plurality of suction pipes; a cover provided on the upper surface of the table to cover the wafer; a gas supply line to pressurize a space surrounded by the upper surface of the table and the cover; a pressure sensor to detect a pressure in each of the plurality of suction pipes; and a detection device to detect a defect in a region of the wafer sucked by each of the plurality of suction pipes based on the pressure detected by the pressure sensor, if the wafer is sucked, the gas supplied from the gas supply line leaks to the corresponding suction pipe via the defect in a suction region where the defect exists, so that a pressure different from that in a suction region without the defect is obtained, and the detection device detects the pressure variation by the pressure sensor to detect the defect.

2. The semiconductor manufacturing apparatus according to claim 1, characterized in that a concentration meter detects a concentration of the gas supplied from the gas supply line in each of the plurality of suction pipes.

3. The semiconductor manufacturing apparatus according to claim 1 or 2, characterized in that the pressure sensor is provided in each of the plurality of suction pipes.

4. The semiconductor manufacturing apparatus according to claim 1, characterized in that a plurality of valves are provided between the plurality of suction pipes and the pressure sensor, respectively, the detection device sequentially sets the plurality of valves to an open state, and detects a defect in a region of the wafer sucked by the suction pipe corresponding to the valve in the open state based on a pressure in the suction pipe corresponding to the valve in the open state.

5. The semiconductor manufacturing apparatus according to claim 4, characterized in that the detection device detects a defect in a central portion of the wafer after detecting a defect in a peripheral portion of the wafer.

6. The semiconductor manufacturing apparatus according to claim 1 or 2, characterized in that suction ports of the plurality of suction pipes are arranged in a lattice shape in the mounting region.

7. The semiconductor manufacturing apparatus according to claim 1 or 2, characterized in that the gas supplied from the gas supply line is He or N2.

8. The semiconductor manufacturing apparatus according to claim 1 or 2, characterized in that the wafer is formed of a wide bandgap semiconductor.

9. The semiconductor manufacturing apparatus according to claim 8, characterized in that the wide bandgap semiconductor is silicon carbide, gallium nitride-based material, or diamond.

10. A semiconductor device manufacturing method, characterized by: mounting a wafer to a mounting region provided on an upper surface of a table, mounting a cover to the upper surface of the table to cover the wafer, supplying a gas to a space surrounded by the upper surface of the table and the cover to pressurize the wafer, ​ The wafer is sucked to the mounting region by a vacuum pump connected to a plurality of suction pipes extending from the mounting region through the table to the back side of the table, The pressure in each of the plurality of suction pipes is detected while the wafer is sucked to the mounting region by pressurizing the wafer, After the pressure in the plurality of suction pipes is detected, the wafer is cleaned, film-formed, photolithographed, etched, diffusion-processed, or ion-implanted, In the method of manufacturing the semiconductor device, Based on the detected pressure, it is detected whether there is a defect in the region of the wafer sucked by each of the plurality of suction pipes, If the wafer is sucked, the gas leaks to the corresponding suction pipe through the defect in the sucked region where the defect exists, so that a pressure different from that in the sucked region without the defect is obtained, and the pressure variation is detected to detect the defect.

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