Semiconductor device manufacturing apparatus and semiconductor device manufacturing method

Abstract

To provide a technique capable of appropriately removing polycrystalline protrusions.SOLUTION: A semiconductor device manufacturing apparatus includes a laser oscillator capable of irradiating a second main surface of a semiconductor component placed on a stage with a first laser light and a second laser light having a higher output than the first laser light, a scattered light detector that detects scattered light of the first laser light scattered by a polycrystalline protrusion when such a protrusion is present on the second main surface of the semiconductor component, and a laser control unit that causes the laser oscillator to irradiate the protrusion with the second laser light on the basis of the detection result of the scattered light detector.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method. [Background technology]

[0002] When an epitaxial layer is formed on a single-crystal SiC wafer, polycrystalline protrusions that cause cracks in the SiC wafer may form on surfaces of the SiC wafer other than the surface on which the epitaxial layer is formed. In response to this, for example, Patent Document 1 proposes a technology for removing the protrusions by irradiating the entire surface on which the protrusions are formed with laser light, utilizing a difference in laser light absorption rate due to differences in crystallinity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-70617 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, protrusions are not detected and removed, but are removed based only on the difference in laser light absorption rate due to differences in crystallinity, and therefore the laser light cannot be controlled based on the presence or absence, size, etc. of the protrusions, which has led to problems such as incomplete removal of the protrusions and the laser light causing damage such as depressions in the semiconductor substrate.

[0005] Therefore, the present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technique that can appropriately remove polycrystalline protrusions. [Means for solving the problem]

[0006] The semiconductor device manufacturing apparatus according to the present disclosure includes a stage on which a semiconductor member is placed, the semiconductor member including a semiconductor substrate and an epitaxial layer provided on the semiconductor substrate, the semiconductor member having a first main surface of the epitaxial layer opposite the semiconductor substrate and a second main surface of the semiconductor substrate opposite the epitaxial layer, with at least a portion of the second main surface exposed; a laser oscillator capable of irradiating the second main surface of the semiconductor member placed on the stage with a first laser beam and a second laser beam having a higher output than the first laser beam; a scattered light detector that detects scattered light of the first laser beam scattered by a polycrystalline protrusion present on the second main surface of the semiconductor member; and a laser controller that causes the laser oscillator to irradiate the second laser beam onto the protrusion based on the detection result of the scattered light detector. [Effects of the Invention]

[0007] According to the present disclosure, polycrystalline protrusions are detected by scattered light of a first laser beam, and the detected protrusions are irradiated with a second laser beam having a higher output than the first laser beam. With this configuration, the polycrystalline protrusions can be appropriately removed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a configuration of a manufacturing apparatus for a semiconductor device according to a first embodiment. [Figure 2] 1 is a schematic diagram showing a configuration of a manufacturing apparatus for a semiconductor device according to a first embodiment. [Figure 3] 1 is a schematic diagram showing a configuration of a manufacturing apparatus for a semiconductor device according to a first embodiment. [Figure 4] FIG. 10 is a schematic diagram showing the configuration of a manufacturing apparatus for a semiconductor device according to a second embodiment. [Figure 5] FIG. 10 is a schematic diagram showing the configuration of a semiconductor device manufacturing apparatus according to a third embodiment. [Figure 6] FIG. 10 is a schematic diagram showing the configuration of a semiconductor device manufacturing apparatus according to a fourth embodiment. [Figure 7] FIG. 10 is a perspective view showing a semiconductor member according to a fourth embodiment. [Figure 8] FIG. 10 is a schematic diagram showing the configuration of a semiconductor device manufacturing apparatus according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the accompanying drawings. Features described in each of the following embodiments are exemplary, and not all features are necessarily required. In addition, in the following description, similar components in multiple embodiments are denoted by the same or similar reference numerals, and different components will be mainly described. In addition, in the following description, specific positions and directions such as "upper," "lower," "left," "right," "front," or "back" may not necessarily correspond to positions and directions in actual implementation.

[0010] <First Embodiment> 1 is a schematic diagram showing the configuration of a semiconductor device manufacturing apparatus according to the present embodiment 1. The manufacturing apparatus in FIG.

[0011] The semiconductor member 31 includes a SiC wafer 31a serving as a semiconductor substrate and an epitaxial layer 31b provided on the SiC wafer 31a. The semiconductor member 31 has an upper surface, which is a first main surface of the epitaxial layer 31b on the side opposite the SiC wafer 31a, and a lower surface, which is a second main surface of the SiC wafer 31a on the side opposite the epitaxial layer 31b. When the epitaxial layer 31b is formed on the upper surface of the SiC wafer 31a, polycrystalline SiC protrusions 31c may be present on the lower surface of the SiC wafer 31a, i.e., the lower surface of the semiconductor member 31, due to abnormal growth.

[0012] In the first embodiment, the lower surface of the semiconductor member 31 is the C-face of the SiC wafer 31a, that is, the carbon face. In the crystal structure of SiC, the face on which Si is exposed to the outermost surface is called the silicon face, and the face on which C is exposed to the outermost surface is called the carbon face. Since C is exposed to the outermost surface on the carbon face, it is likely to bond with the same C, and depending on the growth gas, protrusions 31c tend to be formed on the carbon face.

[0013] The manufacturing apparatus in Fig. 1 includes a stage 1, one laser oscillator 2, a lens 3, a scattered light detection unit 4, and a laser control unit 5. Note that Fig. 1 illustrates one laser oscillator 2 before and after movement.

[0014] The semiconductor member 31 is placed on the stage 1 with at least a portion of the bottom surface of the semiconductor member 31 exposed. The stage 1, together with the placed semiconductor member 31, is capable of translational movement in the X, Y, and Z directions, and is also capable of rotation in the θ direction corresponding to the circumferential direction of the semiconductor member 31. The stage mechanism 1a translates and rotates the stage 1.

[0015] The laser oscillator 2 is a laser oscillator unit capable of irradiating a first laser beam and a second laser beam having a higher output than the first laser beam onto the lower surface of the semiconductor member 31 placed on the stage 1. In the present embodiment 1, the first laser beam is used to detect the protrusion 31c, and the second laser beam is used to remove the protrusion 31c.

[0016] The laser oscillator 2 is configured to be able to selectively irradiate the underside of the SiC wafer 31a with the first laser light and the second laser light within an angular range in which the amounts of the first laser light and the second laser light penetrating into the interior from the underside of the SiC wafer 31a are equal to or less than a predetermined value. The angular range here refers to, for example, a range in which the amount of each laser light penetrating into the interior is equal to or less than a predetermined value within a range from an angle at which the traveling direction of each laser light is parallel to the underside of the SiC wafer 31a to an angle at which the traveling direction of each laser light is inclined with respect to the underside.

[0017] The lens 3 focuses the laser light emitted from the laser oscillator 2. The lens 3 is movable together with the laser oscillator 2.

[0018] The scattered light detection unit 4 detects scattered light of the first laser light scattered by the protrusion 31c when the protrusion 31c is present on the underside of the semiconductor member 31. The scattered light detection unit 4 is provided in a direction (for example, a direction at 90 degrees with respect to the underside of the SiC wafer 31a) such that it does not detect either the light of the first laser light directly incident from the lens 3 or the light reflected from the underside of the semiconductor member 31 where the protrusion 31c is not provided.

[0019] The laser control unit 5 performs signal processing based on the detection result of the scattered light detection unit 4 to identify the position of the protrusion 31c, and causes the laser oscillator 2 to irradiate the second laser light onto the protrusion 31c, thereby removing the protrusion 31c from the SiC wafer 31a.

[0020] Here, a semiconductor device capable of stable operation under high temperatures and high voltages and capable of high-speed switching can be formed from the SiC wafer 31a, and 4H-type SiC wafers are often used for semiconductor devices used as power devices. The SiC wafer 31a may be a 4H-type single crystal SiC wafer, a 6H-type single crystal SiC wafer, or an SiC wafer having other crystal types. On the other hand, the protrusions 31c are made of polycrystalline SiC.

[0021] When the SiC wafer 31a is a 4H-type single-crystal SiC wafer, the wavelength of the second laser light used to remove the protrusion 31c is selected to be a wavelength that is more easily absorbed by polycrystalline SiC than by 4H-type single-crystal SiC, or a wavelength that has a short penetration depth into the SiC wafer 31a. For example, the wavelength of the second laser light is 600 nm or less, preferably 532 nm or less. In the first embodiment, the wavelength of the second laser light is the third harmonic of a 355 nm YAG laser. In this case, the light energy is 3.5 eV, which is sufficient to process the SiC bandgap of 3.26 V. Note that the conditions of the second laser light described here are merely examples, and appropriate conditions of the second laser light may be selected depending on the protrusion 31c.

[0022] <Operation> In the manufacturing apparatus configured as described above, the laser oscillator 2 irradiates the lower surface of the SiC wafer 31a with a low-power first laser beam horizontally or obliquely. Note that, since no wavelength is found that causes total reflection of laser beam incident on SiC, which has a refractive index of 2.6, from air, which has a refractive index of 1.0, the irradiation angle of the first laser beam that is obliquely irradiated on the lower surface is preferably an irradiation angle that minimizes the amount of light that penetrates into the SiC wafer 31a.

[0023] When a protrusion 31c is present on the underside of the semiconductor member 31, the scattered light detection unit 4 detects the scattered light of the first laser light scattered by the protrusion 31c. As shown in FIG. 2, when a protrusion 31c is present on the underside of the SiC wafer 31a, the scattered light detection unit 4 detects the scattered light. On the other hand, as shown in FIG. 3, when a protrusion 31c is not present on the underside of the SiC wafer 31a, the scattered light detection unit 4 does not detect the scattered light. Therefore, it is possible to determine whether or not a protrusion 31c is present and whether or not the protrusion 31c has been removed by the irradiation of the second laser light based on the detection result of the scattered light detection unit 4.

[0024] When the scattered light detection unit 4 detects scattered light, the laser control unit 5 switches the laser light emitted by the laser oscillator 2 from the first laser light to the second laser light, and causes the laser oscillator 2 to emit the high-power second laser light to the position (e.g., coordinates) where the scattered light was detected. This causes the protrusion 31c to sublimate or fall off and be removed.

[0025] <Manufacturing method> The method for manufacturing a semiconductor device using the above-mentioned manufacturing apparatus includes a growth process for growing an epitaxial layer 31b on the upper surface of the SiC wafer 31a, a transport process for placing the semiconductor member 31 on the stage 1, and a removal process for detecting and removing the protrusions 31c.

[0026] <Growth process> In the growth process, for example, a silane-based gas such as monosilane and a hydrocarbon-based gas such as propane are introduced as growth gases, and a nitrogen-containing gas or a gas containing an element that acts as an n-type dopant for silicon carbide is introduced as a dopant gas. As a result, an epitaxial layer 31b grows on the upper surface of the SiC wafer 31a, forming the semiconductor component 31. The growth gas may flow around to the lower surface of the SiC wafer 31a, resulting in the formation of protrusions 31c made of three-dimensionally grown polycrystalline SiC on the lower surface. In particular, the protrusions 31c tend to form around the outer periphery of the lower surface of the SiC wafer 31a.

[0027] A typical SiC wafer 31a has a diameter of 100 mm to 150 mm and a thickness of 350 μm to 600 μm, but as the size of the SiC wafer 31a increases in diameter, such as 8 inches or 12 inches, the range over which the protrusions 31c are formed increases. For this reason, the larger the diameter of the SiC wafer 31a, the more useful it is to remove the protrusions 31c using the manufacturing apparatus according to the first embodiment.

[0028] <Transportation process> In the transport step, a transport mechanism (not shown) transports the semiconductor member 31 so that the semiconductor member 31 is placed on the stage 1 with at least a part of the bottom surface of the semiconductor member 31 exposed.

[0029] <Removal process> In the removal step, the laser oscillator 2 irradiates the lower surface of the semiconductor member 31, i.e., the lower surface of the SiC wafer 31a, with a low-power first laser beam within the above-mentioned angle range. In the first embodiment, with the lower surface of the SiC wafer 31a placed on the stage 1, the laser oscillator 2 irradiates the first laser beam onto the outer periphery of the lower surface of the semiconductor member 31 while the stage mechanism 1a rotates the stage 1, and the presence or absence of scattered light is detected by the scattered light detection unit 4. If the protrusion 31c is not present, the scattered light detection unit 4 does not detect scattered light, but if the protrusion 31c is present, the scattered light detection unit 4 detects scattered light.

[0030] Laser control unit 5 generates position information of protrusion 31c based on the detection result of scattered light detection unit 4 and rotation information of stage mechanism 1a relative to stage 1, and irradiates protrusion 31c with a high-power second laser light based on the position information. This makes it possible to remove protrusion 31c by sublimation or falling off while suppressing damage such as depression of SiC wafer 31a.

[0031] <Other processes> After the removal step, ion implantation and etching are performed on the semiconductor member 31 to form semiconductor elements on the semiconductor member 31, thereby completing the semiconductor device. The semiconductor elements formed on the semiconductor member 31 are, for example, power semiconductor elements such as diode elements and switching elements. Diode elements include, for example, SBDs (Schottky Barrier Diodes) and PNDs (PN junction diodes). Switching elements include, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), IGBTs (Insulated Gate Bipolar Transistors), and RC-IGBTs (Reverse Conducting - IGBTs).

[0032] <Summary of the First Embodiment> According to the semiconductor device manufacturing apparatus of the first embodiment described above, protrusion 31c is detected by scattered light of a low-power first laser beam, and the detected protrusion 31c is irradiated with a high-power second laser beam. This configuration allows the second laser beam to be irradiated while checking whether or not protrusion 31c has been removed. This makes it possible to prevent incomplete removal of protrusion 31c and damage to SiC wafer 31a, and to efficiently and appropriately remove protrusion 31c.

[0033] Furthermore, according to the first embodiment, the laser oscillator 2 selectively irradiates the underside of the SiC wafer 31a with the first laser beam and the second laser beam within an angle range in which the amount of the first laser beam and the second laser beam penetrating into the interior from the underside of the SiC wafer 31a is equal to or less than a predetermined value. This configuration can prevent damage to the SiC wafer 31a. Furthermore, using a single laser oscillator 2 makes it easy to align the irradiation position of the first laser beam and the irradiation position of the second laser beam.

[0034] Furthermore, according to the first embodiment, the scattered light detecting unit 4 does not detect light of the first laser light that is reflected from the lower surface of the semiconductor member 31 on which the protrusion 31c is not provided. This configuration can improve the detection accuracy of the protrusion 31c.

[0035] In the present embodiment 1, the lower surface of the semiconductor member 31 is the C-plane of the SiC wafer 31a. In this case, since protrusions 31c are likely to be formed on the lower surface of the semiconductor member 31, the effects of the semiconductor device manufacturing apparatus according to the present embodiment 1 as described above are particularly useful.

[0036] <Embodiment 2> 4 is a schematic diagram showing the configuration of the semiconductor device manufacturing apparatus according to the present embodiment 1. The laser oscillation section according to the present embodiment 1 is one laser oscillator 2 that selectively irradiates the first laser beam and the second laser beam.

[0037] In contrast to this, the laser oscillator section according to the second embodiment includes a detection laser oscillator 2a which is a first laser oscillator capable of irradiating the lower surface of the semiconductor member 31 with a first laser beam, and a processing laser oscillator 2b which is a second laser oscillator capable of irradiating the protrusion 31c with a second laser beam. The processing laser oscillator 2b can irradiate the second laser beam in parallel with the irradiation of the first laser beam by the detection laser oscillator 2a.

[0038] 4, the detection laser oscillator 2a and the processing laser oscillator 2b are provided opposite the outer periphery of the lower surface of the SiC wafer 31a, and are provided so as to sandwich the stage 1. However, the positions of the detection laser oscillator 2a and the processing laser oscillator 2b are not limited to those shown in FIG.

[0039] The stage 1 and lens 3 according to the second embodiment are similar to the stage 1 and lens 3 according to the first embodiment. Like the scattered light detection unit 4 according to the first embodiment, when a protrusion 31c is present on the lower surface of the semiconductor member 31, the scattered light detection unit 4 according to the second embodiment detects scattered light of the first laser light scattered by the protrusion 31c.

[0040] The manufacturing apparatus according to the second embodiment includes a transmitted light detection unit 8. The transmitted light detection unit 8 detects transmitted light that has passed through the semiconductor member 31 out of the second laser light irradiated from the processing laser oscillator 2b.

[0041] The laser control unit 5 changes the output power of the first laser beam from the detection laser oscillator 2a and the second laser beam from the processing laser oscillator 2b based on the detection results of the scattered light detection unit 4 and the transmitted light detection unit 8. For example, the laser control unit 5 controls the output power of each laser beam by changing the energy and repetition frequency of the unit pulse of each laser beam based on the detection results of the scattered light detection unit 4 and the transmitted light detection unit 8. Note that the energy and repetition frequency of the unit pulse of the first laser beam from the detection laser oscillator 2a are preferably set as small as possible within a range in which the protrusion 31c can be detected. The energy and repetition frequency of the unit pulse of the second laser beam from the processing laser oscillator 2b are preferably set as large as possible within a range in which the SiC wafer 31a is not damaged.

[0042] <Summary of the second embodiment> According to the semiconductor device manufacturing apparatus of the second embodiment as described above, protrusion 31 c is detected by scattered light of the low-power first laser light, and the detected protrusion 31 c is irradiated with the high-power second laser light. With this configuration, protrusion 31 c can be efficiently and appropriately removed, similarly to the first embodiment.

[0043] Furthermore, according to the second embodiment, the processing laser oscillator 2b is configured to be able to irradiate the second laser light in parallel with the irradiation of the first laser light by the detection laser oscillator 2a. With this configuration, the detection and removal of the protrusion 31c can be performed simultaneously without switching between the first laser light and the second laser light, thereby shortening the processing time.

[0044] Furthermore, according to the second embodiment, the laser control unit 5 changes the output power of the first laser beam from the detection laser oscillator 2a and the second laser beam from the processing laser oscillator 2b based on the detection results of the scattered light detection unit 4 and the detection results of the transmitted light detection unit 8. This configuration can increase redundancy in the detection of the protrusion 31c, and as a result, the output power of the first laser beam and the second laser beam can be optimized. Furthermore, for example, the output power of the second laser beam can be appropriately changed in accordance with the state of the protrusion 31c during removal, thereby improving the accuracy of removing the protrusion 31c.

[0045] <Third Embodiment> Fig. 5 is a schematic diagram showing the configuration of a semiconductor device manufacturing apparatus according to the present embodiment 3. The configuration in Fig. 5 is the same as the configuration in Fig. 4, except that the detection laser oscillator 2a, processing laser oscillator 2b, and laser control unit 5 are replaced with a wavelength-tunable detection laser oscillator 2c, a wavelength-tunable processing laser oscillator 2d, and an analysis laser control unit 5a.

[0046] The tunable detection laser oscillator 2c can change the wavelength of the first laser beam, and the tunable processing laser oscillator 2d can change the wavelength of the second laser beam. The analysis laser control unit 5a identifies at least one of the size, shape, and crystalline state of the protrusion 31c by performing multivariate analysis on the detection results of the scattered light detection unit 4 and the transmitted light detection unit 8 for each wavelength. Note that in this specification, for example, "at least one of A, B, C, ..., and Z" means any one of all combinations of one or more selected from the group A, B, C, ..., and Z. Then, the analysis laser control unit 5a changes the wavelength and output of the second laser beam of the tunable detection laser oscillator 2c based on the identification result of the protrusion 31c.

[0047] <Summary of the Third Embodiment> According to the semiconductor device manufacturing apparatus of the third embodiment, at least one of the size, shape, and crystalline state of the protrusion 31c is identified by performing multivariate analysis on the detection results of the scattered light detection unit 4 and the detection results of the transmitted light detection unit 8 for each wavelength. This configuration allows the state of the protrusion 31c during removal to be detected with high accuracy. Furthermore, the wavelength and output of the second laser light can be appropriately changed according to the state of the protrusion 31c during removal, thereby improving the accuracy of removing the protrusion 31c. Furthermore, for example, the time required to remove the protrusion 31c can be shortened by using, for the second laser light, a wavelength that minimizes scattered light, reflected light, transmitted light, etc., i.e., a wavelength that provides high laser absorption by the protrusion 31c.

[0048] <Modification> Although the third embodiment has been described as being applied to the second embodiment, the present invention is not limited to this. For example, the third embodiment can be applied by adding a transmitted light detector 8 to the first embodiment, adding a laser beam wavelength tunable function to the laser oscillator 2, and replacing the laser controller 5 with an analysis laser controller 5a.

[0049] <Fourth Embodiment> 6 is a schematic diagram showing the configuration of a semiconductor device manufacturing apparatus according to the present embodiment 4. The configuration in FIG. 6 is the same as the configuration in FIG. 5, except that an edge sensor 14 and a stage control unit 15 are added.

[0050] 7, the semiconductor member 31 according to the fourth embodiment is provided with a notch 31d used as a reference for the semiconductor member 31. The edge sensor 14 in FIG. 6 has a notch detection function, and detects the notch 31d provided in the semiconductor member 31 and the edge, which is the peripheral portion of the semiconductor member 31, while the semiconductor member 31 is placed on the stage 1. Based on the detection result of the edge sensor 14, the stage control unit 15 controls the translation and rotation of the stage 1 on which the semiconductor member 31 is placed.

[0051] For example, while the stage control unit 15 rotates the semiconductor member 31 or the like in the θ direction, the edge sensor 14 detects the position of the notch 31d and the edge of the semiconductor member 31 based on reflected or transmitted light obtained by irradiating the edge of the semiconductor member 31. Then, the edge sensor 14 detects the position of the center of the semiconductor member 31 based on the position of the notch 31d and the edge. The stage control unit 15 performs alignment by translating and rotating the stage 1 and the semiconductor member 31 based on the position of the notch 31d and the position of the center of the semiconductor member 31.

[0052] <Summary of the Fourth Embodiment> According to the semiconductor device manufacturing apparatus of the fourth embodiment as described above, the translation and rotation of the stage 1 on which the semiconductor member 31 is placed is controlled based on the detection result of the edge sensor 14. With this configuration, the semiconductor member 31 can be aligned with high precision, and the position of the protrusion 31c of the semiconductor member 31 can be aligned with the irradiation position of the second laser light. As a result, the second laser light can be prevented from being irradiated onto portions of the semiconductor member 31 that do not have the protrusion 31c, and damage to the SiC wafer 31a can be prevented.

[0053] <Modification> In the fourth embodiment, a case where it is applied to the third embodiment has been described, but it is not limited to this, and it may be applied to the first and second embodiments, etc.

[0054] <Fifth Embodiment> Fig. 8 is a schematic diagram showing the configuration of a semiconductor device manufacturing apparatus according to the present embodiment 5. The configuration in Fig. 8 is similar to the configuration in Fig. 6, except that the lens 3 is replaced with a high numerical aperture (high NA) lens 3a and a focal position variable unit 17 is added.

[0055] The high numerical aperture lens 3a is one lens selected from a plurality of lenses with different numerical apertures, and has, for example, a higher numerical aperture than the lens 3. The high numerical aperture lens 3a is selected so that the numerical aperture of the high numerical aperture lens 3a increases as the size of the protrusion 31c in a planar view decreases. For example, when the high numerical aperture lens 3a with a numerical aperture of 0.6 is selected and focused on the protrusion 31c with a laser wavelength of 355 nm, a focused spot diameter of approximately 1 μm can be obtained.

[0056] The selection and setting of the high numerical aperture lens 3a may be performed manually by the user, or the manufacturing apparatus may calculate the size of the protrusion 31c based on at least one of the detection results of the scattered light detection unit 4 and the detection results of the transmitted light detection unit 8, and select and set the high numerical aperture lens 3a based on that size.

[0057] The wavelength-tunable processing laser oscillator 2d irradiates the second laser light onto the protrusion 31c through the selected high-numerical aperture lens 3a. The focal position variable unit 17 calculates the height of the protrusion 31c based on at least one of the detection results of the scattered light detector 4 and the transmitted light detector 8, and changes the focal length of the high-numerical aperture lens 3a used to irradiate the second laser light based on the calculated height. For example, the focal position variable unit 17 shortens the focal length of the high-numerical aperture lens 3a as the protrusion 31c becomes taller. Note that the height of the protrusion 31c is often 20 μm or less.

[0058] <Summary of the Fifth Embodiment> According to the semiconductor device manufacturing apparatus of the fifth embodiment as described above, the second laser light is irradiated onto protrusion 31c through one lens selected from a plurality of lenses having different numerical apertures, and the focal length of the lens used to irradiate the second laser light is changed based on at least one of the detection results of scattered light detection unit 4 and the detection results of transmitted light detection unit 8. With this configuration, at least one of the scattered light information obtained by scattered light detection unit 4 and the transmitted light information of transmitted light detection unit 8 can be fed back to focal position variable unit 17. Therefore, the second laser light can be focused in accordance with the three-dimensional shape of protrusion 31c, and high energy can be applied intensively to protrusion 31c, thereby enabling efficient removal of protrusion 31c.

[0059] <Modification> In embodiment 5, we have explained the case where it is applied to embodiment 4, but this is not limited to this and it may also be applied to embodiments 1, 2, and 3 in which a transmitted light detection unit 8 is added.

[0060] It should be noted that the embodiments and modifications may be freely combined, and the embodiments and modifications may be modified or omitted as appropriate.

[0061] Various aspects of the present disclosure are summarized below as appendices.

[0062] (Appendix 1) a stage on which a semiconductor member including a semiconductor substrate and an epitaxial layer provided on the semiconductor substrate, the semiconductor member having a first main surface of the epitaxial layer on the opposite side to the semiconductor substrate and a second main surface of the semiconductor substrate on the opposite side to the epitaxial layer, is placed with at least a portion of the second main surface exposed; a laser oscillator capable of irradiating the second main surface of the semiconductor member placed on the stage with a first laser beam and a second laser beam having a higher output than the first laser beam; a scattered light detection unit that detects scattered light of the first laser light scattered by a polycrystalline protrusion when the polycrystalline protrusion is present on the second main surface of the semiconductor member; a laser control unit that causes the laser oscillation unit to irradiate the second laser light onto the protrusion based on a detection result of the scattered light detection unit; A semiconductor device manufacturing apparatus comprising:

[0063] (Appendix 2) 2. The semiconductor device manufacturing apparatus according to claim 1, wherein the laser oscillator unit is a single laser oscillator capable of selectively irradiating the first laser light and the second laser light onto the second main surface within an angular range in which the amount of the first laser light and the second laser light penetrating into the interior from the second main surface of the semiconductor substrate is equal to or less than a predetermined value.

[0064] (Appendix 3) The scattered light detection unit 3. The semiconductor device manufacturing apparatus according to claim 2, wherein light of the first laser light reflected from the second main surface on which the protrusion is not provided is not detected.

[0065] (Appendix 4) The laser oscillation unit is a first laser oscillator capable of emitting the first laser light; a second laser oscillator capable of irradiating the second laser light in parallel with the irradiation of the first laser light by the first laser oscillator; 2. A manufacturing apparatus for a semiconductor device according to claim 1, comprising:

[0066] (Appendix 5) a transmitted light detection unit that detects transmitted light of the second laser light that has passed through the semiconductor member; 5. The semiconductor device manufacturing apparatus according to claim 1, wherein the laser control unit changes the output power of each of the first laser light and the second laser light based on the detection result of the scattered light detection unit and the detection result of the transmitted light detection unit.

[0067] (Appendix 6) the laser oscillation unit is capable of changing wavelengths of the first laser light and the second laser light, The semiconductor device manufacturing apparatus of claim 5, wherein the laser control unit identifies at least one of the size, shape, and crystalline state of the protrusion by performing multivariate analysis on the detection results of the scattered light detection unit and the detection results of the transmitted light detection unit for each wavelength.

[0068] (Appendix 7) the stage is capable of translational movement and rotation together with the semiconductor member placed thereon; an edge sensor that detects a notch provided in the semiconductor member and an edge of the semiconductor member when the semiconductor member is placed on the stage; a stage control unit that controls translation and rotation of the stage on which the semiconductor member is placed based on the detection result of the edge sensor; 7. The semiconductor device manufacturing apparatus according to claim 1, further comprising:

[0069] (Appendix 8) the laser oscillator irradiates the second laser light onto the protrusion through one lens selected from a plurality of lenses having different numerical apertures; 7. The semiconductor device manufacturing apparatus according to claim 5, further comprising a focal position variable unit that changes a focal length of the one lens used to irradiate the second laser light based on at least one of a detection result of the scattered light detection unit and a detection result of the transmitted light detection unit.

[0070] (Appendix 9) the semiconductor substrate is a SiC wafer, 9. The semiconductor device manufacturing apparatus according to claim 1, wherein the second main surface is a C-plane of the SiC wafer.

[0071] (Appendix 10) forming a semiconductor member including a semiconductor substrate and an epitaxial layer provided on the semiconductor substrate, the semiconductor member having a first main surface of the epitaxial layer opposite to the semiconductor substrate and a second main surface of the semiconductor substrate opposite to the epitaxial layer; placing the semiconductor member on a stage with at least a portion of the second main surface exposed; irradiating the second main surface of the semiconductor member placed on the stage with a first laser light; detecting scattered light of the first laser light scattered by a polycrystalline protrusion when the polycrystalline protrusion is present on the second main surface; irradiating the protrusion with a second laser beam having a higher output than the first laser beam based on the detection result of the scattered light; A method for manufacturing a semiconductor device, comprising: [Explanation of symbols]

[0072] 1 stage, 2 laser oscillator, 2a detection laser oscillator, 2b processing laser oscillator, 2c tunable wavelength detection laser oscillator, 2d tunable wavelength processing laser oscillator, 3a high numerical aperture lens, 4 scattered light detection unit, 5 laser control unit, 5a analysis laser control unit, 8 transmitted light detection unit, 14 edge sensor, 15 stage control unit, 17 focal position control unit, 31 semiconductor member, 31a SiC wafer, 31b epitaxial layer, 31c protrusion, 31d notch.

Claims

1. a stage on which a semiconductor member including a semiconductor substrate and an epitaxial layer provided on the semiconductor substrate, the semiconductor member having a first main surface of the epitaxial layer on a side opposite to the semiconductor substrate and a second main surface of the semiconductor substrate on a side opposite to the epitaxial layer, is placed with at least a portion of the second main surface exposed; a laser oscillator capable of irradiating the second main surface of the semiconductor member placed on the stage with a first laser beam and a second laser beam having a higher output than the first laser beam; a scattered light detection unit that detects scattered light of the first laser light scattered by a polycrystalline protrusion when the polycrystalline protrusion is present on the second main surface of the semiconductor member; a laser control unit that causes the laser oscillation unit to irradiate the second laser light onto the protrusion based on a detection result of the scattered light detection unit; A semiconductor device manufacturing apparatus comprising:

2. 2. The semiconductor device manufacturing apparatus according to claim 1, the laser oscillator unit is a single laser oscillator capable of selectively irradiating the first laser light and the second laser light onto the second main surface within an angular range in which the amount of the first laser light and the second laser light penetrating into the interior from the second main surface of the semiconductor substrate is equal to or less than a predetermined value.

3. 3. The semiconductor device manufacturing apparatus according to claim 2, The scattered light detection unit The semiconductor device manufacturing apparatus does not detect light of the first laser light reflected from the second main surface on which the protrusion is not provided.

4. 2. The semiconductor device manufacturing apparatus according to claim 1, The laser oscillation unit is a first laser oscillator capable of emitting the first laser light; a second laser oscillator capable of irradiating the second laser light in parallel with the irradiation of the first laser light by the first laser oscillator; A semiconductor device manufacturing apparatus comprising:

5. 5. The semiconductor device manufacturing apparatus according to claim 1, a transmitted light detection unit that detects transmitted light of the second laser light that has passed through the semiconductor member; The laser control unit changes the output power of each of the first laser light and the second laser light based on the detection result of the scattered light detection unit and the detection result of the transmitted light detection unit.

6. 6. The semiconductor device manufacturing apparatus according to claim 5, the laser oscillator is capable of changing wavelengths of the first laser light and the second laser light, The laser control unit identifies at least one of the size, shape, and crystalline state of the protrusion by performing multivariate analysis on the detection results of the scattered light detection unit and the detection results of the transmitted light detection unit for each wavelength.

7. 5. The semiconductor device manufacturing apparatus according to claim 1, the stage is capable of translational movement and rotation together with the semiconductor member placed thereon; an edge sensor that detects a notch provided in the semiconductor member and an edge of the semiconductor member when the semiconductor member is placed on the stage; a stage control unit that controls translation and rotation of the stage on which the semiconductor member is placed based on the detection result of the edge sensor; The semiconductor device manufacturing apparatus further comprises:

8. 6. The semiconductor device manufacturing apparatus according to claim 5, the laser oscillator irradiates the second laser light onto the protrusion through one lens selected from a plurality of lenses having different numerical apertures; a focal position varying unit that varies a focal length of the one lens used to irradiate the second laser light based on at least one of a detection result of the scattered light detection unit and a detection result of the transmitted light detection unit.

9. 5. The semiconductor device manufacturing apparatus according to claim 1, the semiconductor substrate is a SiC wafer, The second main surface is a C-plane of the SiC wafer.

10. forming a semiconductor member including a semiconductor substrate and an epitaxial layer provided on the semiconductor substrate, the semiconductor member having a first main surface of the epitaxial layer opposite to the semiconductor substrate and a second main surface of the semiconductor substrate opposite to the epitaxial layer; placing the semiconductor member on a stage with at least a portion of the second main surface exposed; irradiating the second main surface of the semiconductor member placed on the stage with a first laser light; detecting scattered light of the first laser beam scattered by a polycrystalline protrusion present on the second main surface; irradiating the protrusion with a second laser beam having a higher output than the first laser beam based on the detection result of the scattered light; A method for manufacturing a semiconductor device, comprising:

Images