JP2020102537A - Semiconductor object heating device - Google Patents

Abstract

To provide a semiconductor object heating device capable of realizing excellent cutting of a semiconductor object.SOLUTION: A semiconductor object heating device 100 includes a heating plate 101 that heats a GaN ingot 20 in which a reforming region 12 including a plurality of reforming spots 13, a plurality of cracks 14 respectively extending from the plurality of reforming spots 13, and nitrogen gas G is formed, a camera 102 that monitors a crack 14 of the GaN ingot 20 heated by the heating plate 101, and a control unit 105 that controls the heating plate 101 on the basis of the monitoring result of the camera 102.SELECTED DRAWING: Figure 13

Description

The present invention relates to a semiconductor object heating device.

A processing method is known in which a semiconductor target such as a semiconductor ingot is irradiated with laser light to form a modified region including a plurality of modified spots, a plurality of cracks, and a gas inside the semiconductor target. As a technique of this kind, for example, Patent Document 1 describes a technique of condensing a laser beam inside a material to be processed and forming a modified layer in the vicinity of a converging point inside the material to be processed. In the technique described in Patent Document 1, the work material on which the modified layer is formed is heated by a heat source, and the molten modified layer substance is discharged to the outside. As a result, it is possible to suppress the occurrence of cracks in the material to be processed due to an increase in internal pressure due to the gas generated when the modified layer is formed.

JP, 2017-183600, A

In the technique as described above, it is required to accurately propagate a crack in the semiconductor object and realize good cutting of the semiconductor object by utilizing the crack.

It is an object of the present invention to provide a semiconductor object heating device that can achieve good cutting of a semiconductor object.

A semiconductor object heating apparatus according to the present invention is a heating unit for heating a semiconductor object having a plurality of reformed spots, a plurality of reformed regions extending from the plurality of reformed spots, and a reformed region including a gas formed therein. And a monitoring unit that monitors cracks in the semiconductor object heated by the heating unit, and a control unit that controls the heating unit based on the monitoring result of the monitoring unit.

In this semiconductor object heating device, by heating the semiconductor object by the heating unit, the gas contained in the semiconductor object can be expanded to develop a crack. At this time, by monitoring the crack by the monitoring unit, and by controlling the heating unit based on the monitoring result, it is possible to prevent the crack from progressing in an unintended direction or to prevent the crack from spreading unevenly and accurately. It is possible to make progress. Therefore, by utilizing the crack, it becomes possible to realize excellent cutting of the semiconductor object.

In the semiconductor object heating apparatus according to the present invention, the monitoring unit may have a light source that illuminates the semiconductor object. In this case, the monitoring unit enables good monitoring of cracks.

In the semiconductor object heating apparatus according to the present invention, the modified region may be formed inside the semiconductor object along a virtual surface facing the surface of the semiconductor object. In this case, by heating the semiconductor object with the heating unit, it is possible to accurately propagate the crack along the virtual surface and cut the semiconductor object along the virtual surface.

In the semiconductor object heating apparatus according to the present invention, a plurality of modified regions may be formed so as to be arranged in a direction facing the surface. According to this, a plurality of semiconductor members can be obtained from one semiconductor object.

In the semiconductor object heating apparatus according to the present invention, the monitoring unit may include a first observation unit that observes the interference fringes in the processing target area at a depth position corresponding to the virtual surface of the semiconductor object. .. According to this, it becomes possible to monitor the spread of the crack using the observed interference fringes.

In the semiconductor object heating apparatus according to the present invention, the control unit may terminate the heating by the heating unit when the interference fringes observed by the first observation unit are connected to one in the processing target region. .. In this case, it is possible to suppress excessive heating of the semiconductor object by the heating unit, and consequently, defects caused by it.

In the semiconductor object heating apparatus according to the present invention, the control unit raises the heating temperature by the heating unit when the interference fringes observed by the first observation unit are not connected to each other in the processing target region. Good. When the interference fringes are not connected to each other in the processing target region, it is possible to accelerate the progress of the crack along the imaginary plane by increasing the heating temperature because the heating of the semiconductor target is insufficient.

In the semiconductor object heating apparatus according to the present invention, the control unit calculates the width of the crack in the direction facing the surface based on the interference fringes observed by the first observation unit, and the width of the crack exceeds a certain width. In this case, the heating by the heating unit may be terminated. In this case, it is possible to suppress excessive distortion of the semiconductor object due to expansion of the gas, and eventually to prevent defects caused by the distortion.

In the semiconductor object heating apparatus according to the present invention, the monitoring section may include a second observation section that observes the hologram of the processing target area at a depth position corresponding to the virtual surface of the semiconductor object. According to this, it becomes possible to monitor the spread of the crack using the observed hologram.

In the semiconductor object heating apparatus according to the present invention, the control unit calculates the amplitude distribution of the processing target region based on the hologram observed by the second observation unit, and the amplitude distribution is obtained in the entire processing target region. In the case of the above, the heating by the heating unit may be terminated. In this case, it is possible to suppress excessive heating of the semiconductor object by the heating unit, and consequently, defects caused by it.

In the semiconductor object heating apparatus according to the present invention, the control unit calculates the amplitude distribution of the processing target region based on the hologram observed by the second observation unit, and the amplitude distribution is obtained in the entire processing target region. If not, the heating temperature by the heating unit may be increased. When the amplitude distribution cannot be obtained over the entire region to be processed, heating of the semiconductor object by the heating unit is insufficient and the heating temperature can be increased to promote the progress of the crack along the virtual surface.

The semiconductor object heating apparatus according to the present invention includes an unevenness measuring unit that measures unevenness on the surface of the semiconductor object being heated by the heating unit, and the control unit controls the semiconductor object based on the measurement result of the unevenness measuring unit. The value related to the strain amount may be calculated, and when the value related to the strain amount exceeds a certain value, the heating by the heating unit may be terminated. In this case, it is possible to suppress excessive distortion of the semiconductor object due to expansion of the gas, and eventually to prevent defects caused by the distortion.

According to the present invention, it is possible to provide a semiconductor object heating apparatus that can realize good cutting of a semiconductor object.

It is a block diagram of the laser processing apparatus of embodiment. It is a side view of a GaN ingot which is an object of the laser processing method and the semiconductor member manufacturing method of the embodiment. FIG. 3 is a plan view of the GaN ingot shown in FIG. 2. It is a cross-sectional view of the GaN ingot in the heating process of the laser processing method and the semiconductor member manufacturing method of the embodiment. It is a cross-sectional view of the GaN ingot in the heating process of the laser processing method and the semiconductor member manufacturing method of the embodiment. It is a cross-sectional view of the GaN ingot in the heating process of the laser processing method and the semiconductor member manufacturing method of the embodiment. It is a cross-sectional view of the GaN ingot in the heating process of the laser processing method and the semiconductor member manufacturing method of the embodiment. It is a side view of a GaN ingot after a heating process of a laser processing method and a semiconductor member manufacturing method of an embodiment. (A) is a photograph showing a first example of a GaN ingot in the heating step of the laser processing method and the semiconductor member manufacturing method of the first embodiment. (B) is a photograph showing a second example of a GaN ingot in the heating step of the laser processing method and the semiconductor member manufacturing method of the first embodiment. (C) is a photograph showing a third example of a GaN ingot in the heating step of the laser processing method and the semiconductor member manufacturing method of the first embodiment. (D) is a photograph showing a fourth example of a GaN ingot in the heating step of the laser processing method and the semiconductor member manufacturing method of the first embodiment. It is a side view of a GaN ingot in a peripheral region removal process of a laser processing method and a semiconductor member manufacturing method of an embodiment. It is a side view of a GaN ingot in a stimulating process of a laser processing method and a semiconductor member manufacturing method of an embodiment. (A) is a side view of the GaN ingot after the stimulating process in the laser processing method and the semiconductor member manufacturing method of the embodiment. (B) is a side view of a GaN wafer obtained by the laser processing method and the semiconductor member manufacturing method of the embodiment. It is a schematic block diagram of the semiconductor target heating apparatus of 1st Embodiment. It is a figure for explaining calculation of a gap width. 14 is a flowchart showing an example of the operation of the semiconductor object heating apparatus of FIG. 13. (A) is a figure which shows the observation result by a camera when a crack spreads over the whole process target area|region. (B) is a figure which shows the observation result by a camera in case the crack has not spread all over the process target area. It is a photograph figure which shows an example of the observation result of an interference fringe. (A) is a photograph figure which shows an example of the observation result of an interference fringe. FIG. 18B is an enlarged photograph showing the inside of the frame of FIG. (C) is a graph showing the distribution of heights of irregularities on the surface of the GaN ingot. It is a schematic block diagram of the semiconductor target heating apparatus of 2nd Embodiment. It is a graph for demonstrating the example which specifies the depth position of the crack in a GaN ingot. (A) is a figure which shows the amplitude distribution in case a crack does not exist in a process target area. (B) is a diagram showing an amplitude distribution when a crack partially exists in the processing target region. (C) is a figure which shows the amplitude distribution in case the crack has spread in the whole region in the to-be-processed area.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference symbols and redundant description will be omitted.
[Configuration of laser processing equipment]

As shown in FIG. 1, the laser processing apparatus 1 includes a stage 2, a light source 3, a spatial light modulator 4, a condenser lens 5, and a control unit 6. The laser processing apparatus 1 is an apparatus that forms a modified region 12 on the object 11 by irradiating the object 11 with a laser beam L. Hereinafter, the first horizontal direction will be referred to as the X direction, and the second horizontal direction perpendicular to the first horizontal direction will be referred to as the Y direction. The vertical direction is called the Z direction.

The stage 2 supports the object 11 by, for example, adsorbing a film attached to the object 11. In the present embodiment, the stage 2 is movable along each of the X direction and the Y direction. Further, the stage 2 can rotate about an axis parallel to the Z direction as a center line.

The light source 3 outputs a laser beam L that is transparent to the object 11 by, for example, a pulse oscillation method. The spatial light modulator 4 modulates the laser light L output from the light source 3. The spatial light modulator 4 is, for example, a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) spatial light modulator (SLM: Spatial Light Modulator). The condenser lens 5 condenses the laser light L modulated by the spatial light modulator 4. In this embodiment, the spatial light modulator 4 and the condenser lens 5 are movable as a laser irradiation unit along the Z direction.

When the laser light L is condensed inside the target object 11 supported by the stage 2, the laser light L is particularly absorbed at a portion corresponding to the condensing point C of the laser light L, and the laser light L is converted into the inside of the target object 11. A quality region 12 is formed. The modified region 12 is a region in which density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding unmodified region. The modified region 12 includes, for example, a melt-processed region, a crack region, a dielectric breakdown region, and a refractive index change region.

As an example, when the stage 2 is moved along the X direction and the condensing point C is moved relative to the target object 11 along the X direction, a plurality of modified spots 13 are moved along the X direction. It is formed so as to line up in a row. One modified spot 13 is formed by irradiation with one pulse of laser light L. The one-row reforming region 12 is a set of a plurality of reforming spots 13 arranged in one row. The adjacent modified spots 13 may be connected to each other or may be separated from each other depending on the moving speed of the condensing point C relative to the object 11 and the repetition frequency of the laser light L.

The control unit 6 controls the stage 2, the light source 3, the spatial light modulator 4, and the condenser lens 5. The control unit 6 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 6, the software (program) read into the memory or the like is executed by the processor, and the reading and writing of data in the memory and the storage and the communication by the communication device are controlled by the processor. Thereby, the control unit 6 realizes various functions.
[Laser Processing Method and Semiconductor Member Manufacturing Method of First Embodiment]

The object 11 of the laser processing method and the semiconductor member manufacturing method of the first embodiment is, as shown in FIGS. 2 and 3, a GaN ingot (semiconductor ingot, formed of gallium nitride (GaN) in a rectangular plate shape, for example. Semiconductor object) 20. As an example, the GaN ingot 20 has a width of 30 mm and a width of 30 mm, and the GaN ingot 20 has a thickness of 2 mm. The laser processing method and the semiconductor member manufacturing method of the first embodiment are carried out to cut out a plurality of GaN wafers (semiconductor wafers, semiconductor members) 30 from the GaN ingot 20. As an example, the width of the GaN wafer 30 is 10 mm in length and 10 mm in width, and the thickness of the GaN wafer 30 is 100 μm. The shapes of the GaN ingot 20 and the GaN wafer 30 are not particularly limited, and may be circular plate shapes, for example.

First, a laser processing step (first step) using the above laser processing apparatus 1 is performed. In the laser processing step, the laser processing apparatus 1 described above forms the modified region 12 along each of the virtual surfaces 15. Each of the plurality of virtual surfaces 15 is a surface facing the surface 20a of the GaN ingot 20 inside the GaN ingot 20, and is set to be aligned in a direction facing the surface 20a. In the present embodiment, each of the plurality of virtual surfaces 15 is a surface parallel to the surface 20a and has, for example, a rectangular shape. Each of the plurality of virtual surfaces 15 is set so as to overlap each other when viewed from the front surface 20a side. In the GaN ingot 20, a plurality of peripheral areas 16 are set so as to surround each of the plurality of virtual surfaces 15. That is, each of the virtual surfaces 15 does not reach the side surface 20 b of the GaN ingot 20. As an example, the distance between adjacent virtual surfaces 15 is 100 μm, and the width of the peripheral region 16 (in the present embodiment, the distance between the outer edge of the virtual surface 15 and the side surface 20b) is 30 μm or more. A region surrounded by the peripheral region 16 in the GaN ingot 20 is a processing target region R on which the modified region 12 is formed. The processing target region R includes the virtual surface 15. Details of the peripheral region 16 will be described later.

The modified region 12 is sequentially formed for each virtual surface 15 from the side opposite to the surface 20a by irradiation with the laser light L having a wavelength of 532 nm, for example. A plurality of modified regions 12 are provided corresponding to each of the plurality of virtual surfaces 15. Since the formation of the modified region 12 is the same for each of the plurality of virtual surfaces 15, the formation of the modified region 12 along the virtual surface 15 closest to the surface 20a will be described in detail below. In the following, the modified spots 13a, 13b, 13c, 13d described later may be collectively referred to as the modified spot 13, and the cracks 14a, 14b, 14c, 14d described later may be collectively referred to as the crack 14.

As shown in FIG. 4, while the laser processing apparatus 1 makes the laser light L enter the inside of the GaN ingot 20 from the surface 20 a, the condensing point C of the laser light L is moved along the virtual plane 15 in the X direction and Move in Y direction. As a result, the modified region 12 is formed along the virtual surface 15 in the processing target region R surrounded by the peripheral region 16 of the GaN ingot 20.

In the modified region 12, a plurality of modified spots 13a arranged in the X direction and the Y direction, a plurality of cracks 14b respectively extending from the plurality of modified spots 13b, and the GaN ingot 20 being decomposed by the irradiation of the laser light L (chemical change). ) Generated nitrogen gas (gas) G, and gallium (precipitate) deposited by decomposition of the GaN ingot 20 by irradiation of the laser light L. The plurality of modified spots 13a are provided in a matrix on the virtual surface 15. The plurality of cracks 14b include microcracks. The plurality of cracks 14b may be connected to each other or may not be connected to each other. The nitrogen gas G is generated in the plurality of cracks 14. The nitrogen gas G is generated so as to be scattered in one or a plurality of places of the reforming region 12 (processing target region R). In the figure, the modified spot 13a is shown by a black square, and the range in which the crack 14a extends is shown by a broken line (also in FIGS. 5 and 6).

In the present embodiment, when the modified region 12 is formed, it is a region where the modified spot 13a is not formed and is located outside the modified region 12 on the outer surface of the GaN ingot 20 (the surface 20a, the other surface opposite to the surface 20a). The GaN ingot 20 is provided with a peripheral region 16 that prevents the crack 14b from propagating to the surface 20c and the side face 20b) so as to surround the modified region 12. The peripheral region 16 has a frame shape surrounding the modified region 12 when viewed from the Z direction (direction facing the surface 20a). A plurality of peripheral areas 16 are provided corresponding to each of the virtual surfaces 15. The peripheral region 16 further prevents the crack 14b from propagating from the surrounding modified region 12 to another modified region 12 adjacent to the modified region 12. Blocking the growth of the crack 14b is not limited to completely blocking the growth of the crack 14b, and preventing the crack 14b from reaching the outer surface of the GaN ingot 20 as much as possible and preventing the crack 14b from growing. And/or hindering the development of the crack 14b.

In the formation of the modified region 12, on-off irradiation (high-precision laser ON/OFF control) for switching the irradiation of the laser light L to the processing target region R and the peripheral region 16 between on and off is performed, and thus the peripheral region 16 is performed. May be provided. That is, the laser beam L is turned off when the focus point C is located in the peripheral region 16, and the irradiation of the laser beam L is turned on when the focus point C is located inside the peripheral region 16 (region R to be processed). Good.

Instead of or in addition to this, in the formation of the modified region 12, the crack 14b does not propagate under the processing conditions of the laser light L from the modified region 12 to the outer surface of the GaN ingot 20 and/or the other modified region 12. The peripheral region 16 may be provided under the conditions. The processing conditions for providing the peripheral region 16 can be set based on a known technique. The processing conditions for providing the peripheral region 16 include the setting conditions of the energy of the laser light L and the pulse pitch. For example, under the processing conditions for providing the peripheral region 16, the energy of the laser light L is set smaller than the predetermined energy and the pulse pitch is set longer than the predetermined length. Alternatively, in the formation of the modified region 12, the peripheral region 16 may be provided by covering the region other than the region R to be processed of the GaN ingot 20 with a mask that blocks laser incidence.

Instead of or in addition to at least one of these, in the formation of the modified region 12, the bevel portion (also referred to as an inclined portion or a tapered portion) existing on the outer edge of the surface 20a of the GaN ingot 20 is used to generate the laser light L. The peripheral region 16 may be provided by suppressing light collection.

Then, the heating process which heats GaN ingot 20 is implemented using the heating device provided with a heater etc. The heating device includes a heating plate, a device for performing additional laser processing, a heater, a heating furnace, a device for heating by a light source such as an LD (Laser Diode) heater, a laser device, a device for heating by ultrasonic waves, and a device for heating by shock waves. It may include at least one of a device for performing heating and a device for performing heating by electromagnetic waves.

Here, in the GaN ingot 20, the reformed region 12 contains the nitrogen gas G. Therefore, in the heating step, by heating the GaN ingot 20, the nitrogen gas G is expanded and the pressure (internal pressure) of the nitrogen gas G is increased as shown in FIGS. As a result, the nitrogen gas G is connected to one and spreads over the entire virtual surface 15 (processing target region R). Using the pressure of the nitrogen gas G, the plurality of cracks 14 extending from the plurality of reforming spots 13 are connected to each other on the virtual surface 15. A plurality of cracks 14 are propagated along the virtual surface 15 to form a large crack 17 (hereinafter, simply referred to as “crack 17”) across the virtual surface 15.

As shown in FIG. 8, since a plurality of virtual surfaces 15 are set, cracks 17 are formed in each of the virtual surfaces 15 in the heating step. In FIG. 8, a range in which the plurality of modified spots 13, the plurality of cracks 14, and the crack 17 are formed is indicated by a broken line. Molten precipitates may enter the cracks 17. The cracks 14 and 17 are also referred to below as voids.

In the heating step, the peripheral region 16 prevents the plurality of cracks 14 (cracks 17) from propagating, and thus the generated nitrogen gas G can be suppressed from escaping to the outside of the virtual surface 15. The width of the peripheral region 16 is preferably 30 μm or more. The cracks 17 may be formed by connecting the plurality of cracks 14 to each other by applying some force to the GaN ingot 20 by a method other than heating. Further, by forming the plurality of modified spots 13 along the virtual surface 15, the plurality of cracks 14 may be connected to each other to form the crack 17.

FIG. 9A to FIG. 9D are photographic diagrams showing the processing target region R when the GaN ingot 20 having the modified region 12 formed thereon is heated. In the example of FIG. 9A, the heating temperature is 40° C., in the example of FIG. 9B, the heating temperature is 85° C., and in the example of FIG. 9C, the heating temperature is 165° C. In the example of FIG. 9B, the heating temperature is 350° C. As shown in FIGS. 9A to 9C, as the temperature of the GaN ingot 20 rises, the nitrogen gas G expands along the virtual plane 15 and the crack 14 grows. Then, as shown in FIG. 9D, it can be confirmed that the expansion of the nitrogen gas G is suppressed and sealed in the peripheral area 16 and the crack 17 that has expanded is formed over almost the entire virtual surface 15. ..

As a result, the following GaN ingot 20 is obtained as a semiconductor ingot (semiconductor object). As shown in FIG. 8, inside the GaN ingot 20, the modified region 12 is formed along the virtual surface 15 facing the surface 20 a, and the peripheral region 16 provided so as to surround the modified region 12. And The reforming region 12 includes a plurality of reforming spots 13, a plurality of cracks 14 extending from the plurality of reforming spots 13, and a nitrogen gas G, respectively. A plurality of modified regions 12 are provided so as to be aligned in the Z direction. The peripheral region 16 is a region where the modified spot 13 is not formed, and prevents the crack 14 from propagating from the surrounding modified region 12 to the outer surface of the GaN ingot 20. A plurality of peripheral regions 16 are provided corresponding to each of the plurality of modified regions 12. The peripheral region 16 prevents the crack 14 from propagating from the surrounding modified region 12 to another modified region 12 adjacent to the modified region 12.

Then, a peripheral region removing step of removing a plurality of peripheral regions 16 of the GaN ingot 20 is performed. In the peripheral region removing step, as shown in FIG. 10, the laser processing apparatus 1 causes the laser beam to travel along the planned cutting plane M set at the boundary between the peripheral region 16 and the virtual surface 15 (processing target region R). L2 is condensed inside the GaN ingot 20. As a result, a modified region and a crack are formed inside the GaN ingot 20 along the planned cutting surface M. The formation of such modified regions and cracks can be realized by general laser processing for cutting. The GaN ingot 20 is cut along the formed modified region and the crack, and the plurality of peripheral regions 16 are cut off from the GaN ingot 20. The modified region 12 (deposition surface of deposited gallium) is exposed.

In the peripheral edge region removing step, the portion corresponding to the peripheral edge region 16 may be mechanically removed using a blade (crystal cutter) or the like. In the peripheral area removing step, the portion corresponding to the peripheral area 16 may be removed by blade dicing. In the peripheral area removing step, the portion corresponding to the peripheral area 16 may be removed using a wire saw such as a diamond wire. In the peripheral area removing step, the portion corresponding to the peripheral area 16 may be ground (polished) with an abrasive such as a grindstone.

Subsequently, a stimulus applying step of applying a stimulus to the plurality of modified regions 12 formed on the GaN ingot 20 from the outside is performed. In the stimulus applying step, as shown in FIG. 11, the laser processing apparatus 1 focuses the laser light L3 inside the modified region 12 and applies the stimulus to the modified region 12. As a result, the internal pressure releasing effect of the nitrogen gas G contained in the reformed region 12 is also used, and as shown in FIG. 12A, a part of the GaN ingot 20 is exfoliated along the virtual plane 15. Here, the laser light L3 is simultaneously or sequentially focused inside the plurality of modified regions 12, and each part of the GaN ingot 20 is stripped simultaneously or sequentially along the virtual surface 15.

In the stimulus applying step, a stimulus may be mechanically applied to the modified region 12 using a blade or the like. In the stimulus applying step, stimulus may be applied to the modified region 12 by blade dicing. In the stimulation applying step, stimulation may be applied to the modified region 12 using a wire saw such as a diamond wire. In the stimulus applying step, the stimulus may be applied from one outer surface (one direction) of the GaN ingot 20 or may be applied from a plurality of outer surfaces (multi directions). In the stimulation application step, stimulation may be applied to the modified region 12 in a non-contact manner by ultrasonic vibration or the like. In the stimulus applying step, stimulus may be applied to at least the precipitate and the crack 17 in the modified region 12.

Subsequently, as shown in FIG. 12B, a wafer forming process is performed on each part of the separated GaN ingot 20 to remove the modified region 12 and form a wafer. In the wafer forming process, the modified region 12 remaining on each part of the separated GaN ingot 20 is removed by etching or polishing. In the wafer forming process, the modified region 12 may be removed by other mechanical processing, laser processing, or the like. As described above, the GaN ingot 20 is sliced starting from the plurality of modified regions 12. That is, the GaN ingot 20 is cut using the crack 17. As a result, a plurality of GaN wafers 30 are obtained from the GaN ingot 20 with each of the plurality of cracks 17 as a boundary.

[First Embodiment]
Next, the semiconductor object heating apparatus according to the first embodiment will be described. As shown in FIG. 13, the semiconductor object heating apparatus 100 according to the first embodiment is an apparatus used for heating the GaN ingot 20 in the heating step of the above-described semiconductor member manufacturing method. The semiconductor object heating apparatus 100 includes a heating plate 101, a camera 102, a light source 103, a contact type unevenness measuring machine 104, and a control unit 105.

The GaN ingot 20 is a target to be heated. The GaN ingot 20 has a plurality of reforming spots 13, a plurality of cracks 14 extending from each of the plurality of reforming spots 13, and a reforming region 12 (see FIG. 8) including nitrogen gas G formed therein. The modified region 12 is formed inside the GaN ingot 20 along the virtual plane 15. A plurality of modified regions 12 are formed so as to be aligned in the Z direction.

The heating plate 101 is a heating unit that heats the GaN ingot 20. The heating plate 101 heats the GaN ingot 20 under the heating conditions set by the control unit 105. The heating plate 101 is a plate-shaped contact-type heat source that contacts and heats the GaN ingot 20. The GaN ingot 20 is placed on the heating plate 101. The heating plate 101 heats the GaN ingot 20 to expand the nitrogen gas G generated in the GaN ingot 20 and cause an increase in internal pressure due to the nitrogen gas G. Due to the increase in the internal pressure that is induced, the crack 14 propagates along the virtual surface 15 and a large crack 17 is generated along the virtual surface 15.

The camera 102 monitors the crack 14 in the GaN ingot 20 heated by the heating plate 101. The camera 102 constitutes a measurement system for sequentially sensing or monitoring the cracks 14 in the GaN ingot 20 which is being heated by the heating plate 101. The camera 102 includes an image sensor. The camera 102 is a first observation unit that observes the interference fringes in the processing target region R as the spread of the crack 14 at a depth position corresponding to the virtual surface 15 of the GaN ingot 20. The interference fringe has an isolated island shape (see the interference fringe K in FIG. 16). The interference fringes have the shape of closed contour lines. The interference fringe has a fringe corresponding to a Newton ring. The processing target region R is a region where the modified region 12 is formed. The processing target region R is a region corresponding to the semiconductor member to be manufactured. A GaN wafer 30 is mentioned as a semiconductor member. The processing target region R here is a region surrounded by the peripheral region 16 in the GaN ingot 20. The camera 102 transmits the monitoring result to the control unit 105. On the front side of the camera 102 (the GaN ingot 20 side, the upstream side in the optical path), there is an imaging lens (not shown) for focusing (focusing) the observation surface of the GaN ingot 20 on the image sensor of the camera 102. It is provided.

The light source 103 illuminates the GaN ingot 20 placed on the heating plate 101. The camera 102 and the light source 103 are arranged so that the light L0 emitted from the light source 103 and reflected by the GaN ingot 20 enters the camera 102. The camera 102 and the light source 103 form a monitoring unit.

The contact-type unevenness measuring device 104 is an unevenness measuring unit that measures the unevenness height distribution (unevenness distribution) on the surface 20 a of the GaN ingot 20 heated by the heating plate 101. The contact-type unevenness measuring device 104 is a contact-type measuring device that contacts the GaN ingot 20 and measures the unevenness distribution.

The control unit 105 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 105, the software (program) read into the memory or the like is executed by the processor, and the reading and writing of data in the memory and the storage and the communication by the communication device are controlled by the processor. Thereby, the control unit 105 realizes various functions.

The control unit 105 controls the heating plate 101 based on the monitoring result of the camera 102. Specifically, the control unit 105 changes the heating condition of the heating plate 101 according to the monitoring result of the camera 102, and performs the spatiotemporal control of the heating of the GaN ingot 20. As a result, the crack 14 does not reach the outer surface of the GaN ingot 20 while propagating (creating voids) along the virtual surface 15 on the entire surface of the processing target region R.

When the interference fringes observed by the camera 102 are connected to one in the processing target region R, the control unit 105 determines that the crack 14 has spread to the entire processing target region R, and ends the heating by the heating plate 101. .. The connection of one interference fringe means that a plurality of interference fringes are combined and substantially one interference fringe exists in the processing target region R. The end of heating may be realized by stopping the power supply to the heating plate 101. The entire area of the processing target area R may be 90% or more of the processing target area R (hereinafter the same). The determination of the interference fringes by the control unit 105 can be realized by utilizing various known image processing or arithmetic processing.

When the interference fringes observed by the camera 102 are not connected to each other in the processing target region R, the control unit 105 determines that the crack 14 has not spread to the entire processing target region R, and heats the heating plate 101. Raise the temperature. The case where the interference fringes are not connected to one is a case where a plurality of isolated interference fringes are present in the processing target region R. The heating temperature may be increased by controlling the heating temperature of the heating plate 101 to a predetermined temperature.

The control unit 105 calculates the width of the crack 14 (hereinafter, referred to as “gap width”) in the Z direction (direction facing the surface 20a) based on the interference fringe observed by the camera 102. The control unit 105 uses the following equation (1) using the number of fringes (the number of Newton rings) m of the interference fringes, the color of the fringes, and the wavelength λ of the light of that color, and the gap width shown in FIG. Calculate D. The control unit 105 ends the heating by the heating plate 101 when the gap width D exceeds a certain width. The fixed width is a preset specified value.
Gap width D=(m+1/2)×λ×1/2 (1)

The control unit 105 calculates a value related to the strain amount of the GaN ingot 20 based on the measurement result of the contact-type unevenness measuring machine 104, and terminates heating by the heating plate 101 when the value related to the strain amount exceeds a certain value. Specifically, the control unit 105 calculates an approximate curve f representing the unevenness of the surface 20a from the unevenness distribution measured by the contact type unevenness measuring machine 104. A known method can be used to calculate the approximate curve f. The control unit 105 calculates the curvature Kr of the surface 20a as a value related to the amount of strain by the following equation (2) using the approximate curve f and the position a of the surface 20a. The larger the curvature Kr, the greater the degree of bending and distortion of the surface 20a. The control unit 105 terminates the heating by the heating plate 101 when the curvature Kr exceeds a certain value. Although the curvature Kr using the approximated curve f is adopted as the value relating to the amount of distortion, a value using an approximated curved surface representing the unevenness of the surface 20a may be adopted.
Curvature Kr=1/curvature radius Rr
Radius of curvature Rr=(1+f′(a) ² ) ^2/3 /|f″(a)| (2)

Next, an example of the operation of the semiconductor object heating apparatus 100 will be described with reference to the flowchart shown in FIG.

First, the GaN ingot 20 is heated by the heating plate 101 under the set heating conditions (step S1). While the GaN ingot 20 being heated is illuminated with light from the light source 103, the GaN ingot 20 is monitored by the camera 102 (step S2). The control unit 105 determines whether or not the gap width D exceeds a certain width based on the monitoring result of the camera 102 (step S3). In the case of NO in step S3, the control unit 105 determines whether or not the value regarding the strain amount of the GaN ingot 20 exceeds a certain value based on the measurement result of the contact-type unevenness measuring machine 104 (step S4).

In the case of NO in step S4, the control unit 105 determines whether the crack 14 has spread to the entire processing target region R based on the interference fringes observed by the camera 102 (step S5). In step S5, when the interference fringes observed by the camera 102 are connected in the processing target region R, it is determined that the crack 14 has spread to the entire processing target region R. If NO in step S5, the control unit 105 changes the processing conditions so that the heating temperature of the heating plate 101 rises (step S6). After step S6, the process returns to step S1. If YES in step S3, YES in step S4, or YES in step S5, heating by the heating plate 101 is terminated (step S7).

As described above, in the semiconductor object heating apparatus 100, by heating the GaN ingot 20 with the heating plate 101, the nitrogen gas G contained in the GaN ingot 20 can be expanded and the crack 14 can be propagated. At this time, by monitoring the crack 14 with the camera 102 and controlling the heating plate 101 based on the monitoring result, the crack 14 propagates in an unintended direction, the progress of the crack 14 varies, or the crack 14 partially. It is possible to suppress the occurrence of a chip. It is possible to accurately propagate the crack 14. Therefore, it is possible to realize excellent cutting of the GaN ingot 20. It is possible to eliminate defects due to the cracks 14 reaching the outside, and realize high reproducibility and efficient heat treatment.

The semiconductor object heating apparatus 100 further includes a light source 103 that illuminates the GaN ingot 20. In this case, the camera 102 enables good monitoring of the cracks 14 and 17.

In the semiconductor object heating apparatus 100, the modified region 12 is formed inside the GaN ingot 20 along the virtual surface 15 facing the surface 20 a of the GaN ingot 20. In this case, by heating the GaN ingot 20 with the heating plate 101, it is possible to easily form the crack 17 across the virtual surface 15 and cut the GaN ingot 20 along the virtual surface 15.

In the semiconductor object heating apparatus 100, a plurality of modified regions 12 are formed so as to be aligned in a direction facing the surface 20a. According to this, a plurality of GaN wafers 30 can be obtained from one GaN ingot 20.

In the semiconductor object heating apparatus 100, the camera 102 observes the interference fringes in the processing target region R at the depth position corresponding to the virtual plane 15 of the GaN ingot 20. According to this, the spread of the crack 14 can be monitored using the observed interference fringes. By observing the interference fringes, the progress of the phenomenon during heating can be confirmed.

FIG. 16A is a diagram showing an observation result by the camera 102 when the crack 14 spreads over the entire region R to be processed. When the crack 14 spreads over the entire processing target region R, it is found that there is one continuous interference fringe K in the processing target region R, as shown in FIG.

Therefore, in the semiconductor object heating apparatus 100, the control unit 105 ends the heating by the heating plate 101 when the interference fringes K observed by the camera 102 are connected to one in the processing target region R. By ending the heating, the spread of the crack 14 can be stopped. It is possible to suppress excessive heating of the GaN ingot 20 by the heating plate 101, and consequently, defects caused by it.

FIG. 16B is a diagram showing an observation result by the camera 102 when the crack 14 does not spread over the entire processing target region R. When the crack 14 does not extend to the entire processing target region R, it is found that the processing target region R is divided into a plurality of interference fringes K and is not connected to one as shown in FIG. 16B. Be done.

Therefore, in the semiconductor object heating apparatus 100, the control unit 105 raises the heating temperature by the heating plate 101 when the interference fringes K observed by the camera 102 are not connected to one in the processing target region R. By increasing the heating temperature, it is possible to promote the spread of the crack 14 and spread the crack 14 in the entire region R to be processed. It becomes possible to suppress insufficient heating.

In the semiconductor object heating apparatus 100, the control unit 105 calculates the gap width D based on the interference fringes K observed by the camera 102, and when the gap width D exceeds a certain width, heating by the heating plate 101 is performed. To end. In this case, the expansion or distortion of the GaN ingot 20 due to the expansion of the nitrogen gas G can be excessively increased, and consequently, the defects caused by it can be suppressed.

FIG. 17 is a photograph showing an example of an observation result of the interference fringes K when white light illumination is used for the light source 103. For example, regarding the interference fringe K in the circle in FIG. 17, the color of the fringe is purple, the wavelength λ is 380 to 450 nm, and the fringe number m of the interference fringe K is 2. In this case, the void width D (maximum) can be calculated to be 1038 nm by the above equation (1). The size of the irregularities on the surface 20a is 1/2 of the void width D, and can be calculated to be 519 nm. On the other hand, the size (maximum) of the unevenness on the surface 20a when the contact-type unevenness measuring device 104 made contact measurement was 485 nm. From this, it can be confirmed that the gap width D can be accurately calculated with an error of about 7%. It can be confirmed that the semiconductor object heating apparatus 100 is useful for simple monitoring during heating.

The semiconductor object heating apparatus 100 includes a contact-type unevenness measuring device 104 that measures unevenness on the surface 20 a of the GaN ingot 20 heated by the heating plate 101. The control unit 105 calculates a value related to the strain amount of the GaN ingot 20 based on the measurement result of the contact-type unevenness measuring machine 104. The control unit 105 terminates the heating by the heating plate 101 when the value related to the strain amount exceeds a certain value. This makes it possible to suppress excessive distortion or warpage of the GaN ingot 20 due to the expansion of the nitrogen gas, and eventually to prevent defects caused thereby.

FIG. 18A is a photograph showing an example of the observation result of the interference fringes K. FIG. 18B is an enlarged photograph showing the inside of the frame of FIG. FIG. 18C is a graph showing the height distribution of the unevenness on the surface 20 a of the GaN ingot 20. The values in the graph shown in FIG. 18C are the measurement results of the contact-type unevenness measuring machine 104 (noise (With removal processing). The values in the graph shown in FIG. 18C correspond to the approximate curve f at each position along the arrow straight line A1 (see FIG. 18A).

In the graph shown in FIG. 18(c), when the position in the Y direction is 1 mm, the unevenness of the surface 20a is significantly changed, and the curvature Kr obtained by the above equation (2) exceeds a certain value. In this case, as shown in the enlarged view of FIG. 18B, it can be confirmed that the crack CL extending in the Z direction and reaching the surface 20a has occurred. On the other hand, when the position in the Y direction is 5.2 mm, the curvature Kr calculated by the above equation (2) becomes less than a certain value. In this case, it can be confirmed that the crack CL does not occur on the surface 20a and the GaN ingot 20 does not crack or chip.

[Second Embodiment]
Next, the semiconductor object heating apparatus according to the second embodiment will be described. In the description of this embodiment, the same description as that of the first embodiment will be omitted.

As shown in FIG. 19, the semiconductor object heating apparatus 200 according to the second embodiment monitors the GaN ingot 20 during heating by using the digital holography technique. The semiconductor object heating apparatus 200 can simultaneously monitor multiple cracks 14 in the Z direction in the GaN ingot 20 during heating. The semiconductor object heating apparatus 200 includes a heating plate 201, a light source 202, a camera 203, a contact type unevenness measuring machine 204, and a control unit 205.

The heating plate 201 is configured similarly to the heating plate 101 (see FIG. 1).
The light source 202 emits single or white light L1. The light source 202 is a low coherence light source. Part of the light L1 emitted from the light source 202 is reflected by the half mirror HM and enters the GaN ingot 20. The other part of the light L1 emitted from the light source 202 passes through the half mirror HM and enters the reference mirror 207 via the neutral density filter 206. The neutral density filter 206 may include a light blocking plate.

The camera 203 is a second observation unit that observes the hologram of the processing target region R at a depth position corresponding to the virtual surface 15 of the GaN ingot 20. Object light that is reflected light reflected by the GaN ingot 20 enters the camera 203 via the half mirror HM. Further, the reference light, which is the reflected light reflected by the reference mirror 207, enters the camera 203 via the half mirror HM. An imaging lens (not shown) for forming an image on the observation surface of the GaN ingot 20 is provided on the imaging element of the camera 203 on the front side of the camera 203 (the GaN ingot 20 side, the upstream side in the optical path). In addition, in the present embodiment, the imaging lens may be omitted.

A hot mirror 208 is arranged between the half mirror HM and the GaN ingot 20. The contact-type unevenness measuring machine 204 is configured similarly to the contact-type unevenness measuring machine 104 (see FIG. 1). The light source 202, the camera 203, the half mirror HM, and the reference mirror 207 form a monitoring unit.

In such a semiconductor object heating apparatus 200, for example, when the reference mirror 207 is scanned in the optical axis direction, a crack is formed at the depth position (Z direction position) of the GaN ingot 20 where the optical path length is the same as the reference light. When there is 14 (reflection surface), the reference light and the object light interfere with each other, and the hologram having the maximum contrast can be observed by the camera 203. For example, when the crack 14 exists at an arbitrary depth position, the hologram at the depth position of the crack 14 can be observed by the camera 203. By performing numerical calculation from the hologram, the phase distribution (distortion distribution) and the amplitude distribution (reflectance distribution) can be calculated. The scanning of the reference mirror 207 is performed for the coherence length of light, which corresponds to the resolution in the Z direction. For example, scanning of the reference mirror 207 is realized by controlling a drive unit (not shown) that drives the reference mirror 207 by the control unit 205.

From the amplitude distribution of the hologram, the area where the crack 14 extends along the virtual surface 15 can be grasped. The gap width D can be grasped from the phase distribution of the hologram. When a plurality of cracks 14 are present, the reference light intensity may be adjusted by the neutral density filter 206 for each depth position of the crack 14. As shown in FIG. 20, the depth position of the crack 14 from the surface 20a can be specified by the scanning distance of the reference mirror 207 from the position of the hologram on the surface 20a until the next maximum hologram contrast is obtained.

The control unit 205 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 205, the software (program) read into the memory or the like is executed by the processor, and the reading and writing of data in the memory and the storage and the communication by the communication device are controlled by the processor. Thereby, the control unit 205 realizes various functions.

The control unit 205 calculates the amplitude distribution of the processing target region R as the spread of the crack 14 based on the hologram observed by the camera 203. The control unit 205 ends the heating by the heating plate 201 when the amplitude distribution is obtained in the entire region R to be processed. The control unit 205 raises the heating temperature of the heating plate 201 when the amplitude distribution cannot be obtained in the entire region R to be processed. The determination of the amplitude distribution by the control unit 205 can be realized by utilizing, for example, various known image processing or arithmetic processing. Examples of the arithmetic processing include light propagation calculation such as the angular spectrum method.

The control unit 205 uses the phase distribution calculated based on the hologram observed by the camera 203 to calculate the unevenness distribution on the surface 20 a of the GaN ingot 20. Specifically, first, as a reference value, the phase distribution φo is calculated from the hologram on the surface 20a of the GaN ingot 20 before heating. After that, the phase distribution φt is calculated from the hologram of the surface 20a of the GaN ingot 20 at each heating time. The phase difference distribution (φt−φo) that is the difference between them is calculated. Then, the unevenness distribution is calculated by the product of the phase difference distribution (φt−φo)/2π and the wavelength of the light from the light source 202. The determination of the phase distribution by the control unit 205 can be realized by utilizing various known image processing or calculation processing. Examples of the arithmetic processing include light propagation calculation such as the angular spectrum method.

As described above, also in the semiconductor object heating apparatus 200, the same effect as that of the semiconductor object heating apparatus 200 can be obtained. Further, in the semiconductor object heating apparatus 200, the camera 203 observes the hologram of the processing target region R at the depth position corresponding to the virtual surface 15 of the GaN ingot 20. According to this, it becomes possible to monitor the spread of the crack 14 using the observed hologram.

FIG. 21A is a diagram showing the amplitude distribution when the crack 14 does not exist in the processing target region R. FIG. 21B is a diagram showing an amplitude distribution when the crack 14 partially exists in the processing target region R. FIG. 21C is a diagram showing an amplitude distribution when the crack 14 is spread over the entire region R to be processed.

Since the reflected light is obtained only in the portion where the crack 14 has spread, it is possible to obtain the amplitude distribution as a region of high brightness (brightness) only in the portion where the crack 14 has spread. That is, when the crack 14 does not exist, as shown in FIG. 21A, the amplitude distribution cannot be confirmed, and black (low brightness region) is spread over the entire region R to be processed. When the crack 14 partially exists, as shown in FIG. 21B, white (high brightness area) spreads in a part of the processing target region R and black spreads in the other part. When the crack 14 spreads over the entire region R to be processed, as shown in FIG. 21C, the amplitude distribution can be confirmed over the entire region, and white is spread over the entire region R to be processed.

Therefore, in the semiconductor object heating apparatus 200, the control unit 205 calculates the amplitude distribution of the processing target region R based on the hologram observed by the camera 203. The control unit 205 ends the heating by the heating plate 201 when the calculated amplitude distribution is obtained in the entire region R to be processed. As a result, it is possible to suppress excessive heating of the GaN ingot 20 by the heating plate 201 and, consequently, defects caused by it. The control unit 205 raises the heating temperature by the heating plate 201 when the calculated amplitude distribution cannot be obtained in the entire processing target region R. In this case, heating of the GaN ingot 20 by the heating plate 201 is insufficient and the heating temperature can be raised to promote the growth of the crack 14 along the virtual surface 15.

Since the heating plate 201 is used as the heating unit, there is a possibility that the accuracy of measurement by the digital holography technique may be deteriorated due to the distortion of air due to heating. In this case, by providing a detection mechanism that sequentially monitors the strain of the air and a correction mechanism such as a spatial light modulator that corrects the strain of the air based on the detection result of the detection mechanism, the accuracy of measurement can be improved. Can be prevented. The correction of the air distortion is not limited to the correction by the correction mechanism. For example, the data obtained by the monitoring unit may be corrected on the basis of the monitoring result (distortion of the air). In that case, the correction mechanism becomes unnecessary.

The present invention is not limited to the above embodiments.

In the above-described embodiment, various numerical values regarding the laser light L are not limited to those described above. However, in order to prevent the crack 14 from extending from the modified spot 13 to the incident side of the laser light L and the opposite side thereof, the pulse energy of the laser light L is 0.1 μJ to 1 μJ and the pulse of the laser light L is pulsed. The width is preferably 200 fs to 1 ns.

In the above-described embodiment, the semiconductor object is not limited to the GaN ingot 20 and may be, for example, a GaN wafer. The semiconductor member is not limited to the GaN wafer and may be a semiconductor device. One virtual surface may be set for one semiconductor object. The material of the semiconductor object is not particularly limited, and may be SiC (silicon carbide), for example.

In the above-described embodiment, the peripheral region 16 may not be formed. For example, when the peripheral region 16 is not formed, the plurality of modified spots 13 are formed along each of the plurality of virtual planes 15 and then the GaN ingot 20 is etched to form the plurality of GaN wafers 30. It is also possible to obtain.

Although the above-described embodiment includes the heating plates 101 and 201 as the heating unit, the heating unit is not particularly limited. The heating unit is only required to be able to heat the semiconductor object, a device for performing additional laser processing, a heater, a heating furnace, an LD (Laser Diode) heater, a device for heating by a light source such as a laser device, and a device for heating by ultrasonic waves. A device that heats by a shock wave, a device that heats by an electromagnetic wave, or the like may be used. When a plurality of functional elements 32 are formed on the GaN wafer 30 by a semiconductor manufacturing apparatus, this semiconductor manufacturing apparatus may function as a heating unit.

The monitoring unit for monitoring cracks is not limited to the configuration of the above-described embodiment, and a known interferometric measurement device may be used. The unevenness measuring unit for measuring the unevenness of the surface 20a of the GaN ingot 20 is not limited to the contact type unevenness measuring machines 104 and 204 of the above-described embodiment, and a laser displacement measuring machine or the like may be used. The unevenness of the surface 20a can be estimated from the gap width D (maximum) calculated using the above equation (1) as described above, and is calculated based on the hologram observed by the camera 203. It is also possible to estimate from the phase distribution obtained. In this case, the contact type unevenness measuring machines 104 and 204 are unnecessary.

One embodiment of the present invention can also be regarded as a laser processing apparatus, a laser processing method, a semiconductor member manufacturing apparatus, or a semiconductor member manufacturing method. The laser processing device 1 is not limited to the one having the above-mentioned configuration. For example, the laser processing device 1 may not include the spatial light modulator 4.

The materials and shapes described above are not limited to the above-described embodiments and modifications, and various materials and shapes can be applied. In addition, each configuration in the above-described embodiment or modification can be arbitrarily applied to each configuration in the other embodiment or modification.

12... Modified region, 13, 13a, 13b, 13c, 13d... Modified spot, 14, 14a, 14b, 14c, 14d... Crack, 15... Virtual plane, 20... GaN ingot (semiconductor object), 20a... Surface , 100, 200... Semiconductor object heating device, 101, 201... Heating plate (heating unit), 102... Camera (monitoring unit, first observation unit), 103... Light source (monitoring unit, first observation unit), 104, 204... Contact-type unevenness measuring device (unevenness measuring unit), 105, 205... Control unit, 202... Light source (monitoring unit, second observing unit), 203... Camera (monitoring unit, second observing unit), 207... Reference mirror (Monitoring section, second observation section), G... Nitrogen gas (gas), HM... Half mirror (monitoring section, second observation section), K... Interference fringes, R... Processing target area.

Claims (12)

A heating unit for heating a semiconductor object in which a reforming region including a plurality of reforming spots and a plurality of cracks extending from the plurality of reforming spots and a gas are formed therein,
A monitoring unit that monitors the crack of the semiconductor object being heated by the heating unit,
A semiconductor object heating device, comprising: a control unit that controls the heating unit based on a monitoring result of the monitoring unit. The semiconductor object heating apparatus according to claim 1, wherein the monitoring unit has a light source that illuminates the semiconductor object. The semiconductor object heating apparatus according to claim 1, wherein the modified region is formed inside the semiconductor object along an imaginary surface facing a surface of the semiconductor object. The semiconductor object heating apparatus according to claim 3, wherein a plurality of the modified regions are formed so as to be aligned in a direction facing the surface. The semiconductor object heating according to claim 3 or 4, wherein the monitoring unit has a first observation unit that observes interference fringes in a processing target region at a depth position corresponding to the virtual surface of the semiconductor object. apparatus. The semiconductor object according to claim 5, wherein the control unit ends the heating by the heating unit when the interference fringes observed by the first observation unit are connected to one in the processing target region. Heating device. The said control part raises the heating temperature by the said heating part, when the said interference fringe observed by the said 1st observation part is not connected to one in the said process target area|region, The heating temperature of the said heating part is raised. Semiconductor object heating device. The control unit calculates the width of the crack in a direction facing the surface based on the interference fringes observed by the first observation unit, and when the width of the crack exceeds a certain width, The semiconductor object heating apparatus according to claim 5, wherein heating by the heating unit is terminated. The semiconductor according to any one of claims 3 to 8, wherein the monitoring unit has a second observation unit that observes a hologram of a processing target region at a depth position corresponding to the virtual surface of the semiconductor target. Object heating device. The control unit calculates an amplitude distribution of the processing target region based on the hologram observed by the second observation unit, and when the amplitude distribution is obtained in the entire processing target region, the heating unit The semiconductor object heating apparatus according to claim 9, wherein heating is terminated. The control unit calculates an amplitude distribution of the processing target region based on the hologram observed by the second observation unit, and when the amplitude distribution cannot be obtained in the entire processing target region, the heating unit 11. The semiconductor object heating apparatus according to claim 9, which raises the heating temperature according to. An unevenness measuring unit for measuring unevenness of the surface of the semiconductor object being heated by the heating unit is provided,
The control unit calculates a value related to the strain amount of the semiconductor object based on the measurement result of the unevenness measurement unit, and when the value related to the strain amount exceeds a certain value, terminates heating by the heating unit, The semiconductor object heating device according to any one of claims 1 to 11.