JP2023034335A - Alteration layer formation device, and method for manufacturing semiconductor device - Google Patents

Abstract

An object of the present invention is to form an altered layer over the entire target region. SOLUTION: This deteriorated layer forming apparatus has a laser irradiation device (40), an imaging device (50), and a control device (60). The control device forms an altered layer (14) inside the compound semiconductor substrate (12) within the target region by irradiating a laser (L) within the target region of the compound semiconductor substrate (12) with the laser irradiation device. and capturing an image of the compound semiconductor substrate within the target region by the photographing device, and based on the image, a degraded layer unformed region (16) in which the degraded layer is not formed in the target region. and forming the deteriorated layer inside the compound semiconductor substrate in the deteriorated layer-unformed region by irradiating the deteriorated layer-unformed region of the compound semiconductor substrate with a laser using the laser irradiation device. Execute the process. [Selection drawing] Fig. 3

Description

The technology disclosed in the present specification relates to an altered layer forming apparatus and a method for manufacturing a semiconductor device.

In the method for manufacturing a semiconductor device disclosed in Patent Document 1, a modified layer is formed inside the compound semiconductor substrate by irradiating the compound semiconductor substrate with a laser. The altered layer is formed extending along the surface of the compound semiconductor substrate. By forming the altered layer in this way, the compound semiconductor substrate can be processed. For example, a thinner compound semiconductor substrate can be obtained by dividing the compound semiconductor substrate along the altered layer.

Japanese Patent Application Laid-Open No. 2020-102520

When forming a degraded layer inside a compound semiconductor substrate, it may not be possible to form the degraded layer over the entire target region. For example, an altered layer may not be formed in a part of the target area due to equipment failure of the laser irradiation device. In addition, there is a case where the deteriorated layer cannot be formed in a part of the target area because the laser beam is blocked by the foreign matter or the rough surface portion existing on the surface of the compound semiconductor substrate. If the altered layer cannot be formed over the entire target region, the compound semiconductor substrate cannot be processed appropriately. For example, when dividing a compound semiconductor substrate along an altered layer, it may not be possible to divide the compound semiconductor substrate appropriately in a region where the altered layer cannot be formed. This specification proposes a technique for forming an altered layer over the entire target region more reliably than in the past.

A deteriorated layer forming apparatus disclosed in this specification includes a laser irradiation device, an imaging device, and a control device. The control device executes a first degraded layer forming step, a degraded layer non-formed region identifying step, and a second degraded layer forming step. In the first deteriorated layer forming step, the controller irradiates a target region of the compound semiconductor substrate with a laser beam using the laser irradiation device, thereby forming a deteriorated layer inside the compound semiconductor substrate within the target region. Form. In the degraded layer non-formed region specifying step, the control device captures an image of the compound semiconductor substrate in the target region with the photographing device, and based on the image, the degraded layer is formed in the target region. A modified layer non-formed region is specified. In the second degraded layer forming step, the control device irradiates the compound semiconductor in the degraded layer non-formation region of the compound semiconductor substrate with a laser beam using the laser irradiation device. The altered layer is formed inside the substrate.

In this degraded layer forming apparatus, the degraded layer non-formed region identifying step is executed after the first degraded layer forming step. In the degraded layer non-formed region identifying step, a degraded layer non-formed region in which no degraded layer is formed is specified in the target region. Therefore, if the deteriorated layer is not formed in part of the target area due to some abnormality in the first deteriorated layer formed area, the deteriorated layer non-formed area is identified in the deteriorated layer non-formed area identifying step. In the second degraded layer forming step which is executed after the degraded layer non-formed region identification step, the degraded layer non-formed region is irradiated with a laser to form a degraded layer inside the compound semiconductor substrate in the degraded layer non-formed region. is formed. Therefore, according to this deteriorated layer forming apparatus, it is possible to form the deteriorated layer over the entire target region more reliably than the conventional one.

A semiconductor device manufacturing method disclosed in the present specification manufactures a semiconductor device using a deteriorated layer forming apparatus. The deteriorated layer forming device has a laser irradiation device and an imaging device. The manufacturing method includes a first degraded layer forming step, a degraded layer non-formed region identifying step, and a second degraded layer forming step. In the first deteriorated layer forming step, a deteriorated layer is formed inside the compound semiconductor substrate within the target region by irradiating a target region of the compound semiconductor substrate with the laser irradiation device. In the degraded layer-unformed region specifying step, an image of the compound semiconductor substrate within the target region is captured by the photographing device, and a degraded layer in which the degraded layer is not formed in the target region based on the image. Identify unformed regions. In the second deteriorated layer forming step, by irradiating the inside of the deteriorated layer non-formed region of the compound semiconductor substrate with laser by the laser irradiation device, the inside of the compound semiconductor substrate in the deteriorated layer non-formed region is formed with the Forms an altered layer.

In this manufacturing method, when the deteriorated layer is not formed in a part of the target region due to some abnormality in the first deteriorated layer forming region, the deteriorated layer non-formed region is identified in the deteriorated layer non-formed region identifying step. be. Then, in the second degraded layer forming step, a degraded layer is formed in the degraded layer non-formed region. Therefore, according to this manufacturing method, the altered layer can be formed over the entire target region more reliably than the conventional method.

FIG. 2 is a configuration diagram of the deteriorated layer forming apparatus of Example 1. FIG. 2 is a plan view of the GaN substrate 12; FIG. 4 is a flow chart showing a method for manufacturing the semiconductor device of Example 1; FIG. 4 is a diagram showing an image of the GaN substrate 12 photographed by the camera 50; Explanatory drawing of the degraded layer non-formation area identification process. Explanatory drawing of the degraded layer non-formation area identification process. Explanatory drawing of the degraded layer non-formation area identification process. Explanatory drawing of a board|substrate division process. FIG. 10 is a diagram showing peeling failure in the substrate dividing step; FIG. 10 is a diagram showing peeling failure in the substrate dividing step; FIG. 10 is a configuration diagram of an altered layer forming apparatus of Example 2; FIG. 11 is a configuration diagram of an altered layer forming apparatus of Example 3; The block diagram of the deteriorated layer forming apparatus of Example 4. FIG. 10 is a flow chart showing a method for manufacturing a semiconductor device according to Embodiment 4; The block diagram of the deteriorated layer forming apparatus of Example 5. FIG. 11 is a flow chart showing a method for manufacturing a semiconductor device according to Embodiment 6; 14 is a flowchart showing a method for manufacturing a semiconductor device according to Embodiment 7;

In one example of the deteriorated layer forming apparatus disclosed in this specification, the compound semiconductor substrate may be made of a gallium compound.

An example of the deteriorated layer forming apparatus disclosed in this specification may further include a substrate dividing apparatus. In this case, after the control device forms the deteriorated layer inside the compound semiconductor substrate in the deteriorated layer-unformed region, the substrate dividing device divides the compound semiconductor substrate along the deteriorated layer. may be further performed.

According to this configuration, the compound semiconductor substrate can be divided and thinned.

In one example of the deteriorated layer forming apparatus disclosed in the present specification, in the step of specifying the deteriorated layer unformed region, a coordinate system is set with reference to a first feature point in the appearance of the compound semiconductor substrate. , a coordinate range of the altered layer non-formed region may be specified. In this case, in the step of forming the deteriorated layer inside the compound semiconductor substrate in the deteriorated layer-unformed region, a coordinate system is set with reference to a second characteristic point in the appearance of the compound semiconductor substrate. , the laser may be irradiated within the coordinate range.

The first feature point and the second feature point may be feature points (eg, orientation flat, notch, etc.) on the outer shape of the compound semiconductor substrate, or feature points (eg, alignment marks) on the surface of the compound semiconductor substrate. etc.). Also, the second feature point may be the same feature point as the first feature point, or may be a feature point different from the first feature point.

According to this configuration, it is possible to accurately irradiate the laser into the deteriorated layer non-formed region.

In one example of the semiconductor device manufacturing method disclosed in the present specification, after the step of identifying the deteriorated layer unformed region, the deteriorated layer is formed inside the compound semiconductor substrate in the deteriorated layer unformed region. A step of cleaning the compound semiconductor substrate may be further included before the step of forming.

According to this configuration, when a deteriorated layer non-formed region is generated due to adhesion of foreign matter to the surface of the compound semiconductor substrate, the deteriorated layer non-formed region is irradiated with a laser after the foreign matter is removed by cleaning. can be done. Therefore, the deteriorated layer can be more reliably formed inside the compound semiconductor substrate in the deteriorated layer non-formed region.

In one example of the semiconductor device manufacturing method disclosed in the present specification, after the step of identifying the deteriorated layer unformed region, the deteriorated layer is formed inside the compound semiconductor substrate in the deteriorated layer unformed region. A step of planarizing the surface of the compound semiconductor substrate may be further included before the step of forming.

According to this configuration, when a rough surface portion (that is, a portion having a rough surface) is present on the surface of the compound semiconductor substrate, and an altered layer non-formation region is generated, the rough surface portion is removed by the planarization process. A laser can be radiated from the modified layer non-formed region. Therefore, the deteriorated layer can be more reliably formed inside the compound semiconductor substrate in the deteriorated layer non-formed region.

The altered layer forming apparatus 10 of Example 1 shown in FIG. 1 forms an altered layer 14 on a gallium nitride substrate 12 (hereinafter referred to as a GaN substrate 12). The deteriorated layer forming apparatus 10 has a substrate transfer device 20 , a stage 30 , a laser light source 40 , a camera 50 and a control device 60 .

The substrate transfer device 20 carries the GaN substrate 12 into and out of the altered layer forming device 10 . The substrate transfer device 20 places the GaN substrate 12 carried into the altered layer forming device 10 on the stage 30 . FIG. 2 shows the GaN substrate 12 . As shown in FIG. 2, the GaN substrate 12 has orientation flats 12a and 12b. The substrate transfer device 20 incorporates a coarse alignment device. Before the GaN substrate 12 is placed on the stage 30, the coarse alignment apparatus detects characteristic points (for example, orientation flats 12a and 12b) on the appearance of the GaN substrate 12. FIG. The substrate transfer device 20 places the GaN substrate 12 on the stage 30 while adjusting the position and angle of the GaN substrate 12 (the angle around the center of the GaN substrate 12) based on the detected feature points.

The stage 30 is movable in x, y and z directions. The x direction is one direction parallel to the top surface of the stage 30 . The y-direction is parallel to the upper surface of the stage 30 and orthogonal to the x-direction. The z direction is the direction perpendicular to the top surface of the stage 30 .

A laser light source 40 is arranged above the stage 30 . The laser light source 40 irradiates the laser L. A half mirror 42 and a condenser lens 44 are provided as an optical system for the laser L just above the stage 30 . The laser light source 40 irradiates the laser L toward the lower surface of the half mirror 42 . The laser L is reflected by the lower surface of the half mirror 42 . The laser L reflected by the half mirror 42 passes through the condenser lens 44 and irradiates the GaN substrate 12 on the stage 30 . The condenser lens 44 condenses the laser L so that the focal point of the laser L is formed inside the GaN substrate 12 .

Camera 50 is arranged above stage 30 . A mirror 52 is arranged as an optical system of the camera 50 directly above the half mirror 42 . Light transmitted through the half mirror 42 and reflected by the mirror 52 enters the camera 50 . Camera 50 captures an image of GaN substrate 12 placed on stage 30 via mirror 52 and half mirror 42 . Further, although not shown, the deteriorated layer forming apparatus 10 may have a lighting device for irradiating the upper surface 12c of the GaN substrate 12 with light when the camera 50 takes an image.

The control device 60 is electrically connected to the substrate transfer device 20 , stage 30 , laser light source 40 and camera 50 . The control device 60 controls the substrate transfer device 20 , the stage 30 , the laser light source 40 and the camera 50 .

Next, a method for manufacturing the semiconductor device of Example 1 will be described. FIG. 3 shows the manufacturing method of Example 1. FIG. The manufacturing method of Example 1 includes a substrate carrying-in step, a fine alignment step, a degraded layer forming step, a degraded layer unformed region identifying step, a degraded layer reforming step, and a substrate dividing step.

(Substrate loading process)
In the substrate loading step, controller 60 causes substrate transport device 20 to transport GaN substrate 12 onto stage 30 . The GaN substrate 12 is composed of a GaN single crystal. In the substrate loading process, the substrate transfer device 20 places the GaN substrate 12 on the stage 30 while the position and angle of the GaN substrate 12 are adjusted by the rough alignment device. Therefore, the GaN substrate 12 is mounted on the stage 30 with relatively high positional accuracy and angular accuracy.

(Precise alignment process)
Next, controller 60 performs a fine alignment process. In the fine alignment process, the controller 60 captures an image of the GaN substrate 12 on the stage 30 with a camera (for example, the camera 50 or a fine alignment camera not shown), and determines the positions of the orientation flats 12a and 12b of the GaN substrate 12. To detect. Then, the control device 60 calculates the position of the origin O based on the positions of the orientation flats 12a and 12b. For example, the control device 60 calculates the intersection of the extension lines of the orientation flats 12a and 12b as the origin O, as shown in FIG. The control device 60 stores the position of the origin O. FIG. In each subsequent process, the control device 60 sets coordinates indicating a position in the x direction with respect to the origin O (hereinafter referred to as x coordinates) and coordinates indicating a position in the y direction with respect to the origin O (hereinafter referred to as y coordinates). ) and the position on the GaN substrate 12 is controlled based on the xy coordinate system. Also, in the fine alignment process, the controller 60 adjusts the position of the stage 30 in the z direction so that the focal point of the laser L is formed at a predetermined depth inside the GaN substrate 12 .

(Altered layer forming step)
Next, the control device 60 carries out a modified layer forming step. In the modified layer forming process, the controller 60 operates the laser light source 40 . A laser L emitted from a laser light source 40 is reflected by a half mirror 42 , passes through a condenser lens 44 , and irradiates the GaN substrate 12 on the stage 30 . The condenser lens 44 forms a focal point of the laser L inside the GaN substrate 12 (that is, within the thickness of the GaN substrate 12). At the focal position of the laser L, the GaN substrate 12 is heated and decomposed. As a result, an altered layer 14 is formed inside the GaN substrate 12 (more specifically, at the focal position of the laser L). The altered layer 14 is a layer having a structure different from that of the original GaN single crystal. The altered layer 14 is composed of, for example, a deposited layer of gallium. The strength of the altered layer 14 is lower than that of the GaN single crystal. In the modified layer forming step, the controller 60 irradiates the GaN substrate 12 with laser while moving the stage 30 in the x-direction and the y-direction. As a result, the control device 60 irradiates the entire area of the GaN substrate 12 in the x-direction and the y-direction with the laser. Therefore, the altered layer 14 is formed over the entire area of the GaN substrate 12 in the x-direction and the y-direction. Thus, in this embodiment, the target region for forming the altered layer 14 is the entire area of the GaN substrate 12 in the x and y directions.

In the denatured layer forming process, the denatured layer 14 may be formed on a part of the GaN substrate 12 due to the effects of equipment failure, foreign substances adhering to the upper surface 12c of the GaN substrate 12, rough surface portions existing on the upper surface 12c of the GaN substrate 12, and the like. may not be formed. Hereinafter, the region where the altered layer 14 is formed when the GaN substrate 12 is viewed from above is referred to as an altered layer forming region 15, and the region where the altered layer 14 is not formed when the GaN substrate 12 is viewed from above. is referred to as an altered layer non-formed region 16 .

(Deteriorated layer non-formed region specifying step)
Next, the control device 60 carries out a degraded layer non-formed region identifying step. In the degraded layer non-formed region specifying step, the control device 60 captures an image of the GaN substrate 12 with the camera 50 . More specifically, the control device 60 photographs the entire area of the GaN substrate 12 in the x-direction and the y-direction from the upper surface 12c side of the GaN substrate 12 . FIG. 4 shows an example of an image of the GaN substrate 12 photographed in the degraded layer non-formed region identifying step. As shown in FIG. 4 , in the image captured by the camera 50 , the degraded layer non-formed region 16 appears as a whiter region than the degraded layer formed region 15 . The control device 60 specifies the deteriorated layer formed region 15 and the deteriorated layer non-formed region 16 based on the photographed image. 5 to 7 are enlarged images of the deteriorated layer formed region 15 and the deteriorated layer non-formed region 16. FIG. FIG. 5 is an image taken by the camera 50. As shown in FIG. In FIG. 5 , the gray area is the deteriorated layer formed area 15 and the white area is the deteriorated layer non-formed area 16 . The control device 60 calculates an image by binarizing the luminance value of each pixel of the image captured by the camera 50 using a value between white and gray as a threshold value. For example, the control device 60 calculates the image of FIG. 6 as a binarized image of the image of FIG. Next, the control device 60 performs noise removal processing on the binarized image. For example, the control device 60 performs noise removal processing on the image shown in FIG. 5 to obtain the image shown in FIG. smoothed image). The control device 60 identifies the black region as the degraded layer formed region 15 and the white region as the degraded layer non-formed region 16 in the image after the noise removal processing. The control device 60 calculates the coordinate range 16r of the deteriorated layer unformed region 16 based on the image after the noise removal processing. A coordinate range 16r of the altered layer non-formed region 16 is a coordinate range represented by the xy coordinate system set in the fine alignment process. The control device 60 stores the calculated coordinate range 16r.

As shown in FIG. 3, the control device 60 determines whether or not the degraded layer non-formed region 16 exists after the degraded layer non-formed region identifying step. When the degraded layer non-formed region is specified in the degraded layer non-formed region specifying step, the control device 60 carries out the degraded layer reforming step. On the other hand, when no deteriorated layer formed region is identified in the deteriorated layer non-formed region identifying step, the control device 60 performs the substrate dividing step.

(Degraded layer reforming step)
If the degraded layer non-formation region 16 exists, the control device 60 carries out the degraded layer reforming step. In the degraded layer re-forming step, the control device 60 irradiates the laser L within the coordinate range 16r of the degraded layer non-formed region 16 specified in the degraded layer non-formed region specifying step. More specifically, the controller 60 first moves the GaN substrate 12 by the stage 30 so that the irradiation position of the laser L (that is, the position where the focal point is formed) is positioned within the coordinate range 16r. Next, the controller 60 operates the laser light source 40 to irradiate the laser L within the coordinate range 16r (that is, within the deteriorated layer unformed region 16). As a result, the degraded layer 14 is formed in the degraded layer non-formed region 16 . The controller 60 irradiates the GaN substrate 12 with laser while moving the stage 30 in the x and y directions. Thereby, the control device 60 forms the altered layer 14 over the entire coordinate range 16r. That is, the control device 60 forms the deteriorated layer 14 over the entire area of the deteriorated layer non-formed region 16 (that is, the entire area in the x direction and the y direction). If there are a plurality of degraded layer non-formed regions 16 , the control device 60 forms the degraded layer 14 in each of the degraded layer non-formed regions 16 .

After the degraded layer reforming step, the control device 60 performs the degraded layer non-formed region identifying step again. The control device 60 repeats the degraded layer reforming step and the degraded layer non-formed region identifying step until the degraded layer non-formed region 16 is eliminated. As a result, an altered layer 14 is formed over the entire area of the GaN substrate 12 in the x and y directions.

(substrate dividing process)
When the affected layer non-formation region 16 is removed, the control device 60 causes the substrate transfer device 20 to carry the GaN substrate 12 out of the deteriorated layer forming device 10 . After that, a substrate dividing process is performed. In the substrate dividing step, the GaN substrate 12 is divided along the altered layer 14, as shown in FIG. That is, in the substrate dividing step, force is applied to the portion 12e of the GaN substrate 12 on the side of the upper surface 12c in a direction away from the portion 12f of the GaN substrate 12 on the side of the lower surface 12d. As described above, the strength of the altered layer 14 is lower than that of the GaN single crystal. Therefore, when a force is applied to the portion 12e in a direction away from the portion 12f, the portion 12e is separated from the portion 12f along the altered layer . That is, the GaN substrate 12 is split along the altered layer 14 . Thereafter, various processes such as surface polishing and electrode formation are performed on the portion 12e to manufacture a semiconductor device. According to this manufacturing method, a thin semiconductor device can be manufactured. Further, by smoothing the divided surface of the portion 12f and epitaxially growing a GaN layer on the smoothed divided surface, the portion 12f can be restored to the original thickness of the GaN substrate 12. FIG. After that, the portion 12f can be reused as the GaN substrate 12 to manufacture the semiconductor device.

It should be noted that when the substrate dividing step is performed in a state in which the deteriorated layer non-formed region 16 remains in the GaN substrate 12, the portion 12e does not separate from the portion 12f in the deteriorated layer non-formed region 16 as shown in FIG. Also, as shown in FIG. 10, the GaN substrate 12 is split at a position different from the depth of the altered layer 14 in the altered layer non-formed region 16 . In contrast, if the altered layer 14 is formed over the entire GaN substrate 12 as shown in FIG. 8, the portion 12e can be properly separated from the portion 12f.

FIG. 11 shows an altered layer forming apparatus of Example 2. As shown in FIG. Although the optical system of the camera 50 and the optical system of the laser light source 40 are partially shared in the first embodiment, the camera 50 is provided independently of the optical system of the laser light source 40 in the second embodiment. As shown in FIG. 11, in Example 2, the camera 50 is arranged on the side of the condensing lens 44 . In Example 2, the camera 50 directly captures an image of the GaN substrate 12 . In the deteriorated layer forming apparatus of the second embodiment, as in the first embodiment, the substrate carrying-in step, the precise alignment step, the deteriorated layer forming step, the deteriorated layer non-formed region specifying step, and the deteriorated layer reforming step can be performed. can.

FIG. 12 shows an altered layer forming apparatus of Example 3. As shown in FIG. In Example 3, the camera 50 is arranged at a position away from the optical system of the laser light source 40 . Further, in Example 3, the stage 30 can move between a position directly below the condenser lens 44 and a position directly below the camera 50 . In the deteriorated layer forming apparatus of the third embodiment, the control device 60 performs the substrate loading step, the fine alignment step, and the deteriorated layer formation in the same manner as in the first embodiment while the stage 30 is arranged directly below the condenser lens 44. Carry out the process.

In Example 3, the control device 60 causes the stage 30 to move the GaN substrate 12 to directly below the camera 50 at the start of the degraded layer non-formed region identifying step. After that, the control device 60 captures an image of the GaN substrate 12 with the camera 50 and specifies the coordinate range 16r of the altered layer unformed region 16 .

In Example 3, the controller 60 causes the stage 30 to move the GaN substrate 12 to just below the condenser lens 44 at the start of the deteriorated layer reforming process. After that, the control device 60 performs the deteriorated layer reforming process in the same manner as in the first embodiment. After the deteriorated layer re-forming process, the substrate dividing process is performed in the same manner as in the first embodiment.

In the third embodiment, the fine alignment process may be performed again when the stage 30 is moved (that is, at the start of the degraded layer non-formed region identification process and the degraded layer reformation process). In this case, in the degraded layer re-forming process, the origin O (that is, the xy coordinate system) is set in the same manner as in the degraded layer non-formed region identification process, so that the degraded layer 14 is accurately formed in the degraded layer non-formed region 16. can be formed.

FIG. 13 shows an altered layer forming apparatus of Example 4. In FIG. In the deteriorated layer forming apparatus of Example 4, a stage 30a for laser processing and a stage 30b for photographing are provided independently. A laser optical system having a laser light source 40, a half mirror 42, a condenser lens 44 and the like is arranged above the stage 30a. A camera 50 is provided on the stage 30b. Each of the stages 30a, 30b is movable in the x-, y-, and z-directions. The substrate transfer device 20 transfers the GaN substrate 12 between the stage 30a and the stage 30b in addition to loading and unloading the GaN substrate 12 with respect to the altered layer forming device.

FIG. 14 shows the manufacturing method of Example 4. FIG. In Example 4, the controller 60 causes the substrate transfer device 20 to transfer the GaN substrate 12 onto the stage 30a in the substrate loading step. Next, the controller 60 performs the first fine alignment process. The first fine alignment process is performed in the same manner as the fine alignment process of the first embodiment. That is, the control device 60 photographs the GaN substrate 12 on the stage 30a with an alignment camera (not shown) and detects the positions of the orientation flats 12a and 12b of the GaN substrate 12. FIG. Furthermore, the control device 60 calculates the position of the origin O based on the positions of the orientation flats 12a and 12b. Next, the controller 60 forms the altered layer 14 on the GaN substrate 12 in the same manner as in the altered layer forming step of the first embodiment. That is, the controller 60 irradiates the GaN substrate 12 on the stage 30a with the laser L to form the altered layer 14 over the entire area of the GaN substrate 12 in the x-direction and the y-direction.

Next, the controller 60 carries out the first substrate transfer step. In the first substrate transfer step, the controller 60 causes the substrate transfer device 20 to transfer the GaN substrate 12 from the stage 30a to the stage 30b. After performing the rough alignment, the substrate transfer device 20 places the GaN substrate 12 on the stage 30b. Next, the controller 60 performs a second fine alignment process on the stage 30b. The second fine alignment process is performed in the same manner as the fine alignment process of the first embodiment. That is, the controller 60 photographs the GaN substrate 12 on the stage 30b with the camera 50 or an alignment camera (not shown), and detects the positions of the orientation flats 12a and 12b of the GaN substrate 12. FIG. Furthermore, the control device 60 calculates the position of the origin O based on the positions of the orientation flats 12a and 12b. That is, the control device 60 sets an xy coordinate system.

Next, the control device 60 carries out the degraded layer non-formed region identifying step in the same manner as in the first embodiment. That is, the control device 60 captures an image of the GaN substrate 12 with the camera 50 and specifies the altered layer formed region 15 and the altered layer non-formed region 16 based on the captured image. A coordinate range 16r of the degraded layer unformed region 16 is a coordinate range represented by the xy coordinate system set in the second fine alignment process. The control device 60 stores the calculated coordinate range 16r.

If the deteriorated layer non-formation region 16 exists, the control device 60 performs the second substrate transfer step. In the second substrate transfer step, the controller 60 causes the substrate transfer device 20 to transfer the GaN substrate 12 from the stage 30b to the stage 30a. After performing the rough alignment, the substrate transfer device 20 places the GaN substrate 12 on the stage 30a. Next, the controller 60 performs a third fine alignment process on the stage 30a. The third fine alignment process is performed in the same manner as the fine alignment process of the first embodiment. That is, the control device 60 photographs the GaN substrate 12 on the stage 30a with an alignment camera (not shown) and detects the positions of the orientation flats 12a and 12b of the GaN substrate 12. FIG. Furthermore, the control device 60 calculates the position of the origin O based on the positions of the orientation flats 12a and 12b. In the third fine alignment process, the origin O is set at the same position as in the second fine alignment process. That is, in the third fine alignment process, the same xy coordinate system as in the second fine alignment process is set.

Next, the control device 60 forms the deteriorated layer 14 in the deteriorated layer unformed region 16 in the same manner as in the deteriorated layer re-forming process of the first embodiment. That is, the controller 60 irradiates the GaN substrate 12 with the laser L to form the altered layer 14 in the entire coordinate range 16r specified in the altered layer non-formed region specifying step.

The control device 60 repeats the degraded layer non-formed region specifying step and the degraded layer reforming step until the degraded layer non-formed region 16 is eliminated. When the degraded layer non-formed region 16 is removed, the control device 60 unloads the GaN substrate 12 from the degraded layer forming apparatus. Thereafter, a substrate dividing step is performed in the same manner as in Example 1, and semiconductor devices are manufactured using the GaN substrate 12 after division.

In addition, in the second fine alignment process and the third fine alignment process, the xy coordinate system is set with the orientation flats 12a and 12b as a reference. However, in the second fine alignment process and the third fine alignment process, a common xy coordinate system may be set based on different feature points of the GaN substrate 12 .

FIG. 15 shows an altered layer forming apparatus of Example 5. As shown in FIG. The deteriorated layer forming apparatus of Example 5 is obtained by adding a substrate dividing apparatus 70 to the deteriorated layer forming apparatus of Example 1. FIG. The deteriorated layer forming apparatus of Example 5 is the same as the deteriorated layer forming apparatus of Example 1, except that the substrate dividing device 70 is added.

In the deteriorated layer forming apparatus of the fifth embodiment, the control device 60 performs the substrate loading process, the precise alignment process, the deteriorated layer forming process, the deteriorated layer non-formed region specifying process, and the deteriorated layer reforming process in the same manner as in the first embodiment. implement. In the substrate splitting process, the controller 60 splits the GaN substrate 12 by the substrate splitter 70 . The substrate dividing device 70 has a first supporting section that supports the upper surface 12c of the GaN substrate 12 by suction or adhesion, and a second support section that supports the lower surface 12d of the GaN substrate 12 by suction or adhesion. Controller 60 divides GaN substrate 12 as shown in FIG. 8 by moving the first support away from the second support. Thus, the deteriorated layer forming apparatus of Example 5 can perform up to the substrate dividing step.

As described above, in the degraded layer forming step, the laser L may be blocked by foreign matter adhering to the upper surface of the GaN substrate 12, resulting in the degraded layer non-formed region 16 in some cases. As shown in FIG. 16, in the manufacturing method of Example 6, the cleaning step is performed after the degraded layer non-formed region identifying step and before the degraded layer reforming step in order to remove foreign matter. The manufacturing method of Example 6 can be carried out by any of the deteriorated layer forming apparatuses of Examples 1-5.

In the manufacturing method of the sixth embodiment, when the degraded layer non-formed region 16 is specified in the degraded layer non-formed region specifying step, the control device 60 moves the GaN substrate 12 out of the degraded layer forming device by the substrate transfer device 20. Take out. After that, a cleaning step for cleaning the surface of the GaN substrate 12 is performed. Foreign matter is removed from the surface of the GaN substrate 12 in the cleaning process. After performing the cleaning process, the GaN substrate 12 is carried into the degraded layer forming apparatus by the substrate transfer device 20, and the degraded layer reforming process is performed. Since foreign matter has been removed from the surface of the GaN substrate 12, the altered layer 14 can be properly formed in the altered layer unformed region 16 in the altered layer reforming step.

As described above, in the denatured layer forming process, the denatured layer non-formed region 16 may occur due to the scattering of the laser beam L by the rough surface portion of the upper surface of the GaN substrate 12 . As shown in FIG. 17, in the manufacturing method of Example 7, in order to remove the rough surface portion, the planarization step is performed after the degraded layer non-formed region identifying step and before the degraded layer reforming step. The production method of Example 7 can be carried out by any of the deteriorated layer forming apparatuses of Examples 1-5.

In the manufacturing method of the seventh embodiment, when the degraded layer non-formed region 16 is specified in the degraded layer non-formed region specifying step, the control device 60 moves the GaN substrate 12 out of the degraded layer forming device by the substrate transfer device 20 . Take out. After that, a planarization process is performed to planarize the surface of the GaN substrate 12 by polishing, etching, or the like. In the planarization process, the rough surface is removed from the surface of the GaN substrate 12 . After performing the planarization process, the GaN substrate 12 is carried into the degraded layer forming apparatus by the substrate transfer device 20, and the degraded layer reforming process is performed. Since the rough surface portion is removed from the surface of the GaN substrate 12, the degraded layer 14 can be appropriately formed in the degraded layer unformed region 16 in the degraded layer reforming process.

Note that both the cleaning step of the sixth embodiment and the planarization step of the seventh embodiment may be performed when the deteriorated layer non-formed region 16 is identified in the degraded layer non-formed region identifying step.

Note that, in the above-described example, the degraded layer non-formed region identifying step was performed after the degraded layer forming step. However, the degraded layer non-formed region identifying step may be performed while performing the degraded layer forming step. That is, while performing the deteriorated layer forming step, an image of the region after laser irradiation may be taken to identify the deteriorated layer non-formed region.

Moreover, in the above-described embodiment, the entire area of the GaN substrate 12 in the x-direction and the y-direction was the target area for forming the altered layer 14 . However, only a part of the GaN substrate 12 in the x-direction and the y-direction may be the target area for forming the altered layer 14 .

Further, in the above-described examples, the object to be processed was the GaN substrate. Since the GaN substrate has optical transparency, it is easy to distinguish between the altered layer formed region 15 and the altered layer non-formed region 16 in the image taken by the camera 50 . However, the object to be processed may be a compound semiconductor substrate other than the GaN substrate. The compound semiconductor substrate to be processed may not have optical transparency. Even if the compound semiconductor substrate does not have optical transparency, there may be a difference in appearance between the degraded layer formed region 15 and the degraded layer non-formed region 16 . It is possible to distinguish between the region 15 and the region 16 where no deteriorated layer is formed.

The laser light source 40 of the embodiment is an example of a laser irradiation device. The camera 50 of the embodiment is an example of a photographing device.

Although the embodiments have been described in detail above, they are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in this specification or drawings simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

10: Degraded layer forming apparatus, 12: Gallium nitride substrate, 14: Degraded layer, 15: Degraded layer forming region, 16: Degraded layer non-formation region, 30: Stage, 40: Laser light source, 50: Camera

Claims (10)

An altered layer forming device,
a laser irradiation device (40);
an imaging device (50);
a controller (60);
has
The control device
forming an altered layer (14) inside the compound semiconductor substrate (12) within the target region by irradiating a laser (L) within the target region of the compound semiconductor substrate (12) with the laser irradiation device;
A step of capturing an image of the compound semiconductor substrate within the target region by the imaging device, and specifying a degraded layer non-formation region (16) in the target region where the degraded layer is not formed, based on the image. and,
forming the deteriorated layer inside the compound semiconductor substrate in the deteriorated layer unformed region by irradiating the deteriorated layer unformed region of the compound semiconductor substrate with the laser irradiation device;
run the
Altered layer forming device. 2. The deteriorated layer forming apparatus according to claim 1, wherein said compound semiconductor substrate is composed of a gallium compound. further comprising a substrate dividing device (70);
After forming the deteriorated layer inside the compound semiconductor substrate in the region where the deteriorated layer is not formed, the controller further performs a step of dividing the compound semiconductor substrate along the deteriorated layer by the substrate dividing device. do,
The deteriorated layer forming apparatus according to claim 1 or 2. In the step of specifying the modified layer non-formed region, the coordinate range of the modified layer non-formed region is set in a state that a coordinate system is set based on the first characteristic points (12a, 12b) in the appearance of the compound semiconductor substrate. identify the
In the step of forming the altered layer inside the compound semiconductor substrate in the altered layer non-formed region, a coordinate system is set with reference to second feature points (12a, 12b) in the appearance of the compound semiconductor substrate. irradiating a laser within the coordinate range in the state,
The deteriorated layer forming apparatus according to any one of claims 1 to 3. A manufacturing method for manufacturing a semiconductor device using an altered layer forming apparatus,
The deteriorated layer forming device is
a laser irradiation device;
a photographic device;
has
The manufacturing method is
forming an altered layer inside the compound semiconductor substrate in the target region by irradiating the target region of the compound semiconductor substrate with the laser irradiation device;
capturing an image of the compound semiconductor substrate within the target region by the imaging device, and identifying a degraded layer-unformed region in the target region where the degraded layer is not formed, based on the image;
forming the deteriorated layer inside the compound semiconductor substrate in the deteriorated layer unformed region by irradiating the deteriorated layer unformed region of the compound semiconductor substrate with the laser irradiation device;
having
Production method. 6. The manufacturing method according to claim 5, wherein said compound semiconductor substrate is composed of a gallium compound. 7. The manufacturing method according to claim 5, further comprising the step of dividing said compound semiconductor substrate along said altered layer after forming said altered layer inside said compound semiconductor substrate in said altered layer unformed region. Method. In the step of identifying the modified layer non-formed region, a coordinate range of the modified layer non-formed region is identified in a state in which a coordinate system is set with reference to a first feature point in the appearance of the compound semiconductor substrate,
In the step of forming the altered layer inside the compound semiconductor substrate in the altered layer-unformed region, the coordinate system is set with reference to a second characteristic point in the appearance of the compound semiconductor substrate, and the coordinates are Irradiate the laser within the range,
The production method according to any one of claims 5-7. cleaning the compound semiconductor substrate after the step of identifying the altered layer non-formed region and before the step of forming the altered layer inside the compound semiconductor substrate in the altered layer non-formed region; The production method according to any one of claims 5 to 8, further comprising the step of a surface of the compound semiconductor substrate after the step of identifying the altered layer non-formed region and before the step of forming the altered layer inside the compound semiconductor substrate in the degraded layer non-formed region; The manufacturing method according to any one of claims 5 to 9, further comprising a step of flattening.

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