JP7260295B2 - Semiconductor object heating device - Google Patents

Description

The present invention relates to a semiconductor object heating apparatus.

2. Description of the Related Art A processing method is known in which a semiconductor object such as a semiconductor ingot is irradiated with a laser beam to form a modified region containing a plurality of modified spots, a plurality of cracks, and gas inside the semiconductor object. As a technique of this kind, for example, Patent Literature 1 describes a technique in which a laser beam is focused inside a workpiece to form a modified layer in the vicinity of the focus point inside the workpiece. In the technique described in Patent Document 1, a material to be processed on which a modified layer is formed is heated by a heat source, and the molten modified layer material is discharged to the outside. This suppresses cracks in the workpiece due to an increase in internal pressure due to gas generated during formation of the modified layer.

Japanese Patent Application Laid-Open No. 2017-183600

In the above-described techniques, it is required to develop a crack in a semiconductor object with high accuracy and to cut the semiconductor object satisfactorily using the crack.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor object heating apparatus capable of realizing good cutting of a semiconductor object.

A heating apparatus for a semiconductor object according to the present invention is a heating unit that heats a semiconductor object having a plurality of modified spots and a modified region including a plurality of cracks extending from the plurality of modified spots and a gas. a monitoring unit for monitoring cracks in the semiconductor object being heated by the heating unit; and a control unit for controlling the heating unit based on the monitoring result of the monitoring unit.

In this semiconductor object heating apparatus, by heating the semiconductor object with the heating unit, the gas contained in the semiconductor object can be expanded and the crack can be propagated. At this time, the crack is monitored by the monitoring unit, and the heating unit is controlled based on the monitoring results to prevent the crack from growing in an unintended direction and to prevent the crack from growing inconsistently, and the crack can be accurately detected. It is possible to progress. Therefore, by using the cracks, it is possible to achieve 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 for illuminating 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 plane facing the surface of the semiconductor object. In this case, by heating the semiconductor object with the heating unit, the crack can be propagated along the virtual plane with high accuracy, and the semiconductor object can be cut along the virtual plane.

In the semiconductor object heating apparatus according to the present invention, a plurality of modified regions may be formed so as to line up in a direction facing the surface. According to this, it is possible to obtain a plurality of semiconductor members from one semiconductor object.

In the semiconductor object heating apparatus according to the present invention, the monitoring unit may have a first observation unit that observes interference fringes in the processing target area at a depth position corresponding to the virtual plane of the semiconductor object. . According to this, it is 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, by extension, defects caused thereby.

In the semiconductor object heating apparatus according to the present invention, the control unit increases the heating temperature of the heating unit when the interference fringes observed by the first observation unit are not connected to one in the processing target region. good too. If the interference fringes are not connected to one in the processing target area, the heating temperature of the semiconductor object is considered to be insufficient by the heating unit, and the heating temperature can be increased to promote the propagation of the crack along the imaginary plane.

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 determines that the width of the crack exceeds a certain width. In this case, heating by the heating unit may be terminated. In this case, it is possible to prevent the distortion of the semiconductor object from becoming excessively large due to the expansion of the gas, and consequently, the defects caused thereby.

In the semiconductor object heating apparatus according to the present invention, the monitoring unit may have a second observation unit that observes the hologram of the processing target area at a depth position corresponding to the virtual plane of the semiconductor object. According to this, it is 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 over the entire processing target region. The heating by the heating unit may be terminated when the In this case, it is possible to suppress excessive heating of the semiconductor object by the heating unit and, by extension, defects caused thereby.

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 over the entire processing target region. If not, the heating temperature of the heating unit may be increased. If the amplitude distribution cannot be obtained in the entire region to be processed, it is possible to raise the heating temperature by considering that the semiconductor object is insufficiently heated by the heating unit, and to promote the propagation of the crack along the imaginary plane.

A semiconductor object heating apparatus according to the present invention includes an unevenness measuring unit for measuring unevenness of the surface of a semiconductor object being heated by the heating unit, and a control unit controls the semiconductor object based on the measurement result of the unevenness measuring unit. A value related to the amount of strain may be calculated, and heating by the heating unit may be terminated when the value related to the amount of strain exceeds a certain value. In this case, it is possible to prevent the distortion of the semiconductor object from becoming excessively large due to the expansion of the gas, and consequently, the defects caused thereby.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the semiconductor target heating apparatus which can implement|achieve the cutting|disconnection of a semiconductor target satisfactorily.

1 is a configuration diagram of a laser processing apparatus according to an embodiment; FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a GaN ingot that is an object of a laser processing method and a semiconductor member manufacturing method according to an embodiment; 3 is a plan view of the GaN ingot shown in FIG. 2; FIG. FIG. 3 is a cross-sectional view of a GaN ingot in a heating step of the laser processing method and semiconductor member manufacturing method of the embodiment; FIG. 3 is a cross-sectional view of a GaN ingot in a heating step of the laser processing method and semiconductor member manufacturing method of the embodiment; FIG. 3 is a cross-sectional view of a GaN ingot in a heating step of the laser processing method and semiconductor member manufacturing method of the embodiment; FIG. 3 is a cross-sectional view of a GaN ingot in a heating step of the laser processing method and semiconductor member manufacturing method of the embodiment; FIG. 4 is a side view of the GaN ingot after the heating step of the laser processing method and the semiconductor member manufacturing method of the embodiment; (a) is a photograph view showing a first example of a GaN ingot in a heating step of the laser processing method and the semiconductor member manufacturing method of the first embodiment. (b) is a photographic view showing a second example of a GaN ingot in a heating step of the laser processing method and the semiconductor member manufacturing method of the first embodiment. (c) is a photographic view showing a third example of a GaN ingot in a heating step of the laser processing method and semiconductor member manufacturing method of the first embodiment. (d) is a photographic view showing a fourth example of the GaN ingot in the heating step of the laser processing method and semiconductor member manufacturing method of the first embodiment. FIG. 4 is a side view of the GaN ingot in the peripheral region removing step of the laser processing method and the semiconductor member manufacturing method of the embodiment; FIG. 4 is a side view of the GaN ingot in the stimulation step of the laser processing method and semiconductor member manufacturing method of the embodiment; (a) is a side view of a GaN ingot after a stimulus application step 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. 1 is a schematic configuration diagram of a semiconductor object heating apparatus according to a first embodiment; FIG. It is a figure for demonstrating calculation of space|gap width. 14 is a flow chart showing an example of the operation of the semiconductor object heating apparatus of FIG. 13; (a) is a diagram showing observation results by a camera when a crack spreads over the entire region to be processed. (b) is a diagram showing observation results by a camera when a crack has not spread over the entire area to be processed. It is a photograph figure which shows an example of the observation result of an interference fringe. (a) is a photographic diagram showing an example of observation results of interference fringes. (b) is a photographic view showing an enlarged view of the frame of FIG. 18(a). (c) is a graph showing the distribution of the height of irregularities on the surface of the GaN ingot. It is a schematic block diagram of the semiconductor target heating apparatus of 2nd Embodiment. FIG. 4 is a graph for explaining an example of specifying the depth position of cracks in a GaN ingot; FIG. (a) is a diagram showing an amplitude distribution when no crack exists in a region to be processed. (b) is a diagram showing an amplitude distribution when a crack partially exists in the processing target region. (c) is a diagram showing an amplitude distribution when a crack spreads over the entire region in the processing target region.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted.
[Configuration of laser processing device]

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 controller 6. The laser processing apparatus 1 is an apparatus that forms a modified region 12 on an object 11 by irradiating the object 11 with a laser beam L. As shown in FIG. 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. Also, the vertical direction is referred to as the Z direction.

The stage 2 supports the object 11 by sucking a film attached to the object 11, for example. In this embodiment, the stage 2 is movable along each of the X direction and the Y direction. Also, the stage 2 is rotatable about an axis parallel to the Z direction.

The light source 3 outputs laser light L having transparency 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). A condenser lens 5 collects 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 along the Z direction as a laser irradiation unit.

When the laser beam L is condensed inside the object 11 supported by the stage 2, the laser beam L is particularly absorbed in a portion corresponding to the converging point C of the laser beam L, and the inside of the object 11 is reformed. A textured region 12 is formed. Modified region 12 is a region that differs in density, refractive index, mechanical strength, and other physical properties from surrounding unmodified regions. The modified region 12 includes, for example, a melting process region, a crack region, a dielectric breakdown region, a refractive index change region, and the like.

As an example, when the stage 2 is moved along the X direction and the focal point C is moved relative to the object 11 along the X direction, a plurality of modified spots 13 are arranged along the X direction. formed in rows. One modified spot 13 is formed by irradiation with one pulse of laser light L. FIG. A row of modified regions 12 is a set of a plurality of modified spots 13 arranged in a row. Adjacent modified spots 13 may be connected to each other or separated from each other depending on the relative moving speed of the focal point C with respect to the object 11 and the repetition frequency of the laser light L.

A control unit 6 controls the stage 2 , light source 3 , spatial light modulator 4 and condenser lens 5 . The control unit 6 is configured as a computer device including a processor, memory, storage, communication device, and the like. In the control unit 6, the software (program) loaded into the memory or the like is executed by the processor, and the reading and writing of data in the memory and storage and the communication by the communication device are controlled by the processor. Thereby, the control part 6 implement|achieves various functions.
[Laser processing method and semiconductor member manufacturing method of the first embodiment]

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

First, a laser processing step (first step) using the laser processing apparatus 1 described above is performed. In the laser processing step, the laser processing apparatus 1 described above forms the modified regions 12 along each of the plurality of virtual surfaces 15 . Each of the plurality of virtual planes 15 is a plane facing surface 20a of GaN ingot 20 inside GaN ingot 20, and is set to be aligned in a direction facing surface 20a. In this embodiment, each of the plurality of virtual planes 15 is a plane parallel to the surface 20a and has, for example, a rectangular shape. Each of the plurality of virtual planes 15 is set so as to overlap each other when viewed from the surface 20a side. GaN ingot 20 is provided with a plurality of peripheral regions 16 so as to surround each of the plurality of virtual planes 15 . In other words, each of the multiple 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 this 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 to be formed. The processing target region R includes the virtual surface 15 . Details of the peripheral region 16 will be described later.

Formation of the modified regions 12 is sequentially performed for each virtual surface 15 from the side opposite to the surface 20a by irradiation with a laser beam 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. Hereinafter, modified spots 13a, 13b, 13c, and 13d, which will be described later, will be collectively referred to as modified spots 13, and cracks 14a, 14b, 14c, and 14d, which will be described later, will be collectively referred to as cracks 14 in some cases.

As shown in FIG. 4, the laser processing apparatus 1 causes the laser beam L to enter the inside of the GaN ingot 20 from the surface 20a, and moves the focal point C of the laser beam L along the virtual plane 15 in the X direction and Move in the Y direction. Thereby, the modified region 12 is formed along the imaginary plane 15 in the processing target region R surrounded by the peripheral region 16 in the GaN ingot 20 .

The modified region 12 includes a plurality of modified spots 13a arranged in the X direction and the Y direction, a plurality of cracks 14b extending from the plurality of modified spots 13b, and the GaN ingot 20 decomposed (chemically changed) by the irradiation of the laser light L. ), and gallium (precipitate) deposited when the GaN ingot 20 is decomposed by the laser beam L irradiation. A plurality of modified spots 13 a are provided in a matrix on the imaginary plane 15 . The plurality of cracks 14b include microcracks. The plurality of cracks 14b may or may not be connected to each other. Nitrogen gas G is generated within the plurality of cracks 14 . The nitrogen gas G is generated so as to be scattered in one or a plurality of locations of the modified region 12 (processing target region R). In the drawing, the modified spots 13a are indicated by black squares, and the range where the cracks 14a extend is indicated by broken lines (the same applies to FIGS. 5 and 6).

In the present embodiment, the modified region 12 is formed in a region where the modified spot 13a is not formed, and from the modified region 12 to the outer surface of the GaN ingot 20 (surface 20a, other surface on the opposite side to the surface 20a). A peripheral region 16 is provided in the GaN ingot 20 to surround the modified region 12 to prevent cracks 14b from propagating to the surface 20c and the side surface 20b). The peripheral region 16 has a frame shape surrounding the modified region 12 when viewed in the Z direction (the direction facing the surface 20a). A plurality of peripheral regions 16 are provided corresponding to each of the plurality of virtual surfaces 15 . The peripheral region 16 further prevents cracks 14b from propagating from the surrounding modified region 12 to other modified regions 12 adjacent to the modified region 12 in question. To prevent the crack 14b from growing is not limited to completely preventing the crack 14b from growing, but to prevent the crack 14b from reaching the outer surface of the GaN ingot 20 as much as possible, or to prevent the crack 14b from growing. and/or hindering the growth of the crack 14b.

In the formation of the modified region 12, by performing on/off irradiation (high-precision laser ON/OFF control) for switching on and off the irradiation of the laser light L to the processing target region R and the peripheral region 16, the peripheral region 16 may be provided. That is, when the condensing point C is located in the peripheral region 16, the laser light L is turned off, and when the condensing point C is located inside the peripheral region 16 (processing target region R), the irradiation of the laser light L is turned on. good too.

Alternatively or additionally, in forming the modified region 12, the processing conditions of the laser beam L are set so that the crack 14b does not propagate from the modified region 12 to the outer surface of the GaN ingot 20 and/or other modified regions 12. A marginal region 16 may be provided provided that it is conditional. Processing conditions for providing the peripheral edge region 16 can be set based on known techniques. The processing conditions for providing the peripheral region 16 include setting conditions for the energy of the laser light L and the pulse pitch. For example, in the processing conditions for providing the peripheral region 16, the energy of the laser light L is set to be smaller than a predetermined energy and the pulse pitch is set to be longer than a predetermined length. Alternatively, in forming the modified region 12 , the peripheral region 16 may be provided by covering areas other than the processing target region R of the GaN ingot 20 with a mask that blocks laser incidence.

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

Subsequently, a heating step of heating the GaN ingot 20 is performed using a heating device including a heater or the like. Heating devices include heating plates, additional laser processing devices, heaters, heating furnaces, LD (Laser Diode) heaters, devices that heat with light sources such as laser devices, devices that heat with ultrasonic waves, and heating with shock waves. At least one of a device for performing heating and a device for heating by electromagnetic waves may be included.

Here, in GaN ingot 20 , nitrogen gas G is contained in modified region 12 . Therefore, in the heating step, the GaN ingot 20 is heated to expand the nitrogen gas G and induce an increase in pressure (internal pressure) of the nitrogen gas G, as shown in FIGS. As a result, the nitrogen gas G is joined together and spread over the entire imaginary surface 15 (region R to be processed). Using the pressure of the nitrogen gas G, the plurality of cracks 14 extending from the plurality of modified spots 13 are connected to each other on the virtual plane 15 . A plurality of cracks 14 are propagated along the imaginary surface 15 to form a large crack 17 (hereinafter simply referred to as "crack 17") extending across the imaginary surface 15.

As shown in FIG. 8, since a plurality of virtual planes 15 are set, cracks 17 are formed in each of the plurality of virtual planes 15 in the heating step. In FIG. 8, a plurality of modified spots 13, a plurality of cracks 14, and a range where cracks 17 are formed are indicated by dashed lines. Cracks 17 may contain molten precipitates. Cracks 14 and 17 are also referred to below as voids.

In the heating step, the peripheral region 16 prevents the cracks 14 (cracks 17 ) from growing, so that the generated nitrogen gas G can be prevented from escaping to the outside of the imaginary surface 15 . It is preferable that the peripheral region 16 has a width of 30 μm or more. By applying some force to the GaN ingot 20 by a method other than heating, the plurality of cracks 14 may be connected to each other to form the cracks 17 . Also, by forming a plurality of modified spots 13 along the imaginary plane 15 , a plurality of cracks 14 may be connected to each other to form a crack 17 .

9(a) to 9(d) 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. 9(a), the heating temperature is 40° C., in the example of FIG. 9(b), the heating temperature is 85° C., and in the example of FIG. 9(c), the heating temperature is 165° C. , in the example of FIG. 9B, the heating temperature is 350.degree. As shown in FIGS. 9A to 9C, as the temperature of the GaN ingot 20 rises, the nitrogen gas G expands along the imaginary plane 15 and cracks 14 grow. Then, as shown in FIG. 9(d), it can be confirmed that expansion of the nitrogen gas G is suppressed and sealed in the peripheral region 16, and a crack 17 that expands over almost the entire area of the imaginary surface 15 is formed. .

As a result of the above, the following GaN ingot 20 is obtained as a semiconductor ingot (semiconductor object). As shown in FIG. 8, the GaN ingot 20 has, inside, a modified region 12 formed along a virtual plane 15 facing the surface 20a and a peripheral region 16 provided so as to surround the modified region 12. And prepare. The modified region 12 includes a plurality of modified spots 13, a plurality of cracks 14 extending from the plurality of modified spots 13, and nitrogen gas G. A plurality of modified regions 12 are provided so as to line up in the Z direction. The peripheral region 16 is a region where the modified spots 13 are not formed, and prevents cracks 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 cracks 14 from propagating from the surrounding modified region 12 to other modified regions 12 adjacent to the modified region 12 .

Subsequently, a peripheral region removing step is performed to remove a plurality of peripheral regions 16 from the GaN ingot 20 . In the peripheral region removing step, as shown in FIG. 10, the laser processing apparatus 1 emits a laser beam along a planned cutting plane M set at the boundary between the peripheral region 16 and the virtual surface 15 (processing target region R). L2 is focused inside the GaN ingot 20 . Thereby, a modified region and a crack are formed inside the GaN ingot 20 along the planned cutting plane M. FIG. 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 regions and cracks to cut off a plurality of peripheral regions 16 from the GaN ingot 20 . The modified region 12 (the deposition surface of deposited gallium) is exposed.

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

Subsequently, a stimulus application step is performed to externally apply a stimulus to the plurality of modified regions 12 formed in the GaN ingot 20 . In the stimulus application step, as shown in FIG. 11, the laser processing apparatus 1 converges the laser beam L3 inside the modified region 12 to apply a stimulus to the modified region 12 . As a result, part of the GaN ingot 20 is exfoliated along the imaginary plane 15 as shown in FIG. Here, the laser light L3 is condensed inside the plurality of modified regions 12 simultaneously or sequentially, and each portion of the GaN ingot 20 is simultaneously or sequentially delaminated along the virtual plane 15 .

In the stimulus application step, a blade or the like may be used to mechanically apply a stimulus to the modified region 12 . In the stimulation applying step, the stimulation may be applied to the modified region 12 by blade dicing. In the stimulus applying step, a wire saw such as a diamond wire may be used to apply the stimulus to the modified region 12 . In the stimulus applying step, the stimulus may be applied from one outer surface (unidirectional) of the GaN ingot 20, or may be applied from a plurality of outer surfaces (multidirectional). In the stimulation application step, the stimulation may be applied to the modified region 12 in a non-contact manner by ultrasonic vibration or the like. In the stimulation step, at least the precipitates and cracks 17 in the modified region 12 should be stimulated.

Subsequently, as shown in FIG. 12(b), each portion of the separated GaN ingot 20 is subjected to a wafer forming step in which the modified region 12 is removed to form a wafer. In the wafering process, the modified region 12 remaining in each part of the peeled 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 crack 17 is used to cut the GaN ingot 20 . 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 boundaries.

[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 semiconductor member manufacturing method described above. A 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 controller 105 .

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

Heating plate 101 is a heating unit that heats GaN ingot 20 . Heating plate 101 heats GaN ingot 20 under the heating conditions set by control unit 105 . The heating plate 101 is a plate-shaped contact heat source that contacts and heats the GaN ingot 20 . A 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 induce an internal pressure rise due to the nitrogen gas G. As shown in FIG. The induced increase in internal pressure causes the crack 14 to grow along the imaginary surface 15 and generate a large crack 17 along the imaginary surface 15 .

Camera 102 monitors cracks 14 in GaN ingot 20 being heated by heating plate 101 . The camera 102 constitutes a measurement system that sequentially senses or monitors cracks 14 in the GaN ingot 20 being heated by the heating plate 101 . Camera 102 includes an imaging device. 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 plane 15 of the GaN ingot 20 . The interference fringes have an isolated island shape (see interference fringes K in FIG. 16). The interference fringes have the shape of closed contour lines. The interference fringes have fringes corresponding to Newton's rings. The processing target region R is a region in which the modified region 12 is formed. The region R to be processed is a region corresponding to the semiconductor member to be manufactured. A GaN wafer 30 is mentioned as a semiconductor member. The region R to be processed here is a region surrounded by the peripheral edge region 16 in the GaN ingot 20 . Camera 102 transmits the monitoring result to control unit 105 . On the front side of camera 102 (on the GaN ingot 20 side, upstream in the optical path), there is an imaging lens (not shown) for forming an image (focusing) of the observation surface of GaN ingot 20 on the imaging element of camera 102 . is provided.

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

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

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

A 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 conditions of the heating plate 101 according to the monitoring result of the camera 102 and controls the heating of the GaN ingot 20 spatio-temporally. As a result, the crack 14 is allowed to grow (form a gap) along the virtual plane 15 over the entire area R to be processed, while preventing the crack 14 from reaching the outer surface of the GaN ingot 20 .

When the interference fringes observed by the camera 102 are connected to one in the processing target region R, the control unit 105 concludes that the crack 14 has spread throughout the processing target region R, and terminates the heating by the heating plate 101. . The fact that the interference fringes are connected to one means that a plurality of interference fringes combine to form substantially one interference fringe in the region R to be processed. The heating may be terminated by stopping power supply to the heating plate 101 . The entire region R to be processed here may be 90% or more of the region R to be processed (the same shall apply hereinafter). Determination of interference fringes by the control unit 105 can be realized using various known image processing or arithmetic processing.

When the interference fringes observed by the camera 102 are not connected to one 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 performs heating by the heating plate 101. Increase temperature. The fact that the interference fringes are not connected to one means that there are a plurality of isolated interference fringes in the region R to be processed. The heating temperature may be increased by controlling the heating temperature under the heating conditions of the heating plate 101 to a predetermined temperature.

Based on the interference fringes observed by the camera 102, 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). The control unit 105 determines the gap width shown in FIG. Calculate D. The controller 105 terminates the heating by the heating plate 101 when the gap width D exceeds a certain width. The constant width is a preset specified value.
Gap width D=(m+1/2)×λ×1/2 (1)

Control unit 105 calculates a value related to the strain amount of GaN ingot 20 based on the measurement results of contact-type unevenness measuring instrument 104, and terminates heating by 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 20 a from the unevenness distribution measured by the contact-type unevenness measuring device 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 distortion by the following equation (2) using the approximated curve f and the position a of the surface 20a. The greater the curvature Kr, the greater the degree of bending and distortion of the surface 20a. The controller 105 terminates the heating by the heating plate 101 when the curvature Kr exceeds a certain value. Although the curvature Kr using the approximation curve f is used as the value related to the amount of strain, a value using an approximation curved surface representing the unevenness of the surface 20a may be used.
Curvature Kr=1/curvature radius Rr
Curvature radius 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 heating plate 101 heats the GaN ingot 20 under 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). Based on the monitoring result of the camera 102, the controller 105 determines whether or not the gap width D has exceeded a certain width (step S3). If NO in step S3, controller 105 determines whether or not the strain amount of GaN ingot 20 exceeds a certain value based on the measurement result of contact-type unevenness measuring instrument 104 (step S4).

If NO in step S4, the control unit 105 determines whether or not the crack 14 has spread over the entire processing target region R based on the interference fringes observed by the camera 102 (step S5). In step S5 above, when the interference fringes observed by the camera 102 are connected to one in the region R to be processed, it is determined that the crack 14 has spread over the entire region R to be processed. If NO in step S5, the control unit 105 changes the processing conditions so that the heating temperature of the heating plate 101 is increased (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 results, the crack 14 may grow in an unintended direction, the progress of the crack 14 may vary, and the crack 14 may partially crack. It is possible to suppress the occurrence of chipping. It becomes possible to propagate the crack 14 with high accuracy. Therefore, it is possible to realize good cutting of the GaN ingot 20 . Defects due to cracks 14 reaching the outside can be eliminated, and high reproducibility and efficient heat treatment can be achieved.

Semiconductor object heating apparatus 100 further comprises a light source 103 for illuminating GaN ingot 20 . In this case, the camera 102 allows good monitoring of the cracks 14,17.

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

In the semiconductor object heating apparatus 100, a plurality of modified regions 12 are formed so as to line up in the direction facing the surface 20a. According to this, it is possible to obtain a plurality of GaN wafers 30 from one GaN ingot 20 .

In the semiconductor object heating apparatus 100 , the camera 102 observes interference fringes within the processing target region R at a 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. 16(a) is a view showing the 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 region R to be processed, as shown in FIG.

Therefore, in the semiconductor object heating apparatus 100, the control unit 105 terminates 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 crack 14 can be stopped from spreading. Excessive heating of the GaN ingot 20 by the heating plate 101 and, in turn, defects caused thereby can be suppressed.

FIG. 16(b) is a view showing the result of observation by the camera 102 when the crack 14 has not spread over the entire region R to be processed. When the crack 14 does not spread over the entire region R to be processed, as shown in FIG. be

Therefore, in the semiconductor object heating apparatus 100, the control unit 105 increases the heating temperature of 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, the expansion of the crack 14 can be promoted, and the crack 14 can be expanded throughout the region R to be processed. Insufficient heating can be suppressed.

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. terminate. In this case, it is possible to suppress excessive distortion or warpage of the GaN ingot 20 due to the expansion of the nitrogen gas G, and thus defects caused thereby.

FIG. 17 is a photographic diagram showing an example of observation results of the interference fringes K when white light illumination is used as the light source 103 . For example, the circled interference fringes K in FIG. In this case, the gap width D (maximum) can be calculated to be 1038 nm from the above equation (1). The size of the irregularities on the surface 20a is 1/2 of the gap width D, so it can be calculated to be 519 nm. On the other hand, the size (maximum) of the unevenness of the surface 20a measured by the contact-type unevenness measuring machine 104 was 485 nm. As a result, it can be confirmed that the gap width D can be calculated accurately 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 unevenness measuring device 104 that measures unevenness of the surface 20 a of the GaN ingot 20 being heated by the heating plate 101 . Control unit 105 calculates a value related to the strain amount of GaN ingot 20 based on the measurement result of contact-type unevenness measuring instrument 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, in turn, defects resulting therefrom.

FIG. 18(a) is a photographic diagram showing an example of the observation result of the interference fringes K. FIG. FIG. 18(b) is a photographic view showing an enlarged view of the inside of the frame of FIG. 18(a). FIG. 18(c) is a graph showing the unevenness height distribution on the surface 20a of the GaN ingot 20. The values in the graph shown in FIG. 18(c) are the measurement results (noise with removal processing). The values of the graph shown in FIG. 18(c) correspond to the approximated curve f at each position along the straight arrow A1 (see FIG. 18(a)).

In the graph shown in FIG. 18(c), when the position in the Y direction is 1 mm, the variation in unevenness of the surface 20a is remarkable, 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. 18(b), it can be confirmed that a crack CL extending in the Z direction and reaching the surface 20a is generated. On the other hand, when the position in the Y direction is 5.2 mm, the curvature Kr obtained by the above formula (2) becomes less than a certain value. In this case, it can be confirmed that no crack CL occurs on the surface 20a, and no cracking or chipping of the GaN ingot 20 occurs.

[Second embodiment]
Next, a semiconductor object heating apparatus according to a second embodiment will be described. In the description of the present embodiment, descriptions similar to those of the first embodiment are omitted.

As shown in FIG. 19, the semiconductor object heating apparatus 200 according to the second embodiment monitors the GaN ingot 20 being heated using digital holography technology. The semiconductor object heating apparatus 200 can simultaneously monitor multiple layers of cracks 14 in the Z direction in the GaN ingot 20 being heated. A 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 controller 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. Light source 202 is a low coherence light source. Part of light L1 emitted from light source 202 is reflected by half mirror HM and enters 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 . Neutral density filter 206 may include a light blocking plate.

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

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 in the same manner as the contact-type unevenness measuring machine 104 (see FIG. 1). The light source 202, camera 203, half mirror HM, and reference mirror 207 constitute 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 occurs at the depth position (Z direction position) of the GaN ingot 20 where the optical path length is the same as that of the reference light. If there is 14 (reflecting surface), the reference beam and the object beam interfere and a hologram with maximum contrast can be observed by the camera 203 . For example, if the crack 14 exists at an arbitrary depth position, a hologram at the depth position of the crack 14 can be observed with the camera 203 . By performing numerical calculations from the hologram, its phase distribution (strain distribution) and amplitude distribution (reflectance distribution) can be calculated. The scanning of the reference mirror 207 is performed by 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 region of crack 14 spreading along the virtual plane 15 can be grasped. The gap width D can be grasped from the phase distribution of the hologram. When multiple layers of cracks 14 are present, the reference light intensity may be adjusted by the neutral density filter 206 for each depth position of the cracks 14 . As shown in FIG. 20, the depth position of the crack 14 from the surface 20a can be identified 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, memory, storage, communication device, and the like. In the control unit 205, the software (program) loaded into the memory or the like is executed by the processor, and the reading and writing of data in the memory and 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 terminates the heating by the heating plate 201 when the amplitude distribution is obtained over the entire region R to be processed. The control unit 205 increases the heating temperature of the heating plate 201 when the amplitude distribution cannot be obtained in the entire region R to be processed. Determination of the amplitude distribution by the control unit 205 can be realized using various known image processing or arithmetic processing, for example. The arithmetic processing includes, for example, light propagation calculation such as the angular spectrum method.

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

As described above, the semiconductor object heating apparatus 200 also has the same effects as the semiconductor object heating apparatus 200 . Further, in the semiconductor object heating apparatus 200 , the camera 203 observes the hologram of the processing target region R at a depth position corresponding to the virtual plane 15 of the GaN ingot 20 . This makes it possible to monitor the spread of the crack 14 using the observed hologram.

FIG. 21(a) is a diagram showing the amplitude distribution when the crack 14 does not exist in the region R to be processed. FIG. 21(b) is a diagram showing the amplitude distribution when the crack 14 partially exists in the region R to be processed. FIG. 21(c) is a diagram showing an amplitude distribution when the crack 14 spreads over the entire region R to be processed.

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

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 terminates the heating by the heating plate 201 when the calculated amplitude distribution is obtained over the entire region R to be processed. This makes it possible to suppress excessive heating of the GaN ingot 20 by the heating plate 201 and, in turn, defects resulting therefrom. The control unit 205 increases the heating temperature of the heating plate 201 when the calculated amplitude distribution cannot be obtained in the entire region R to be processed. In this case, heating of GaN ingot 20 by heating plate 201 is insufficient, and the heating temperature can be increased to promote propagation of crack 14 along imaginary plane 15 .

In addition, since the heating plate 201 is used as the heating unit, it is possible that the accuracy of the measurement by the digital holography technique is lowered due to the distortion of the air due to the heating. In this case, by providing a detection mechanism that sequentially monitors the distortion of the air and a correction mechanism such as a spatial light modulator that corrects the distortion of the air based on the detection result of the detection mechanism, the accuracy of measurement can prevent a decline in It should be noted that the correction of air distortion is not limited to correction by the correction mechanism. For example, the data obtained by the monitoring unit may be corrected based on the results of monitoring (distortion of the air). In that case, the correction mechanism becomes unnecessary.

The invention is not limited to the embodiments described above.

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

In the embodiments described above, the semiconductor object is not limited to the GaN ingot 20, but may be, for example, a GaN wafer. The semiconductor member is not limited to a GaN wafer, and may be a semiconductor device. One virtual plane 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 embodiments described above, the peripheral edge region 16 may not be formed. For example, when the peripheral region 16 is not formed, after forming a plurality of modified spots 13 along each of the plurality of virtual planes 15, the GaN ingot 20 is etched to form a 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 section, the heating section is not particularly limited. The heating unit only needs to be able to heat the semiconductor object, and may be an additional laser processing device, a heater, a heating furnace, an LD (Laser Diode) heater, a device that heats with a light source such as a laser device, or a device that heats with ultrasonic waves. , a device that performs heating by shock waves, a device that performs heating by electromagnetic waves, and the like. When forming the plurality of functional elements 32 on the GaN wafer 30 by using a semiconductor manufacturing apparatus, the 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 measuring 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 instruments 104 and 204 of the above-described embodiments, and a laser displacement measuring instrument or the like may be used. As described above, the unevenness of the surface 20a can be estimated from the gap width D (maximum) calculated using the above equation (1). It is also possible to estimate from the phase distribution. 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 having the configuration described above. For example, the laser processing device 1 does not have to include the spatial light modulator 4 .

Various materials and shapes can be applied to each configuration in the above-described embodiments and modifications without being limited to the materials and shapes described above. Also, each configuration in the above-described embodiment or modification can be arbitrarily applied to each configuration in another embodiment or modification.

Reference Signs List 12: modified regions, 13, 13a, 13b, 13c, 13d: modified spots, 14, 14a, 14b, 14c, 14d: cracks, 15: imaginary surface, 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 machine (unevenness measuring unit) 105, 205 Control unit 202 Light source (monitoring unit, second observation unit) 203 Camera (monitoring unit, second observation 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 (10)

a heating unit for heating a semiconductor object in which a modified region including a plurality of modified spots and a plurality of cracks extending from the plurality of modified spots and a gas are formed;
a monitoring unit for monitoring the crack in the semiconductor object being heated by the heating unit;
a control unit that controls the heating unit based on the monitoring result of the monitoring unit;
The modified region is formed inside the semiconductor object along a virtual plane facing the surface of the semiconductor object,
The semiconductor object heating apparatus, wherein the monitoring unit has a first observation unit that observes interference fringes in a processing target area at a depth position corresponding to the virtual plane of the semiconductor object. 2. The semiconductor object according to claim 1, wherein said control unit terminates heating by said heating unit when said interference fringes observed by said first observation unit are connected to one in said processing target region. heating device. 3. The control unit according to claim 1 , wherein the control unit increases the heating temperature of the heating unit when the interference fringes observed by the first observation unit are not connected to one in the processing target region. semiconductor object heating apparatus. 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 when the width of the crack exceeds a certain width, the 2. The semiconductor object heating apparatus according to claim 1 , which terminates heating by the heating unit. a heating unit for heating a semiconductor object in which a modified region including a plurality of modified spots and a plurality of cracks extending from the plurality of modified spots and a gas are formed;
a monitoring unit for monitoring the crack in the semiconductor object being heated by the heating unit;
a control unit that controls the heating unit based on the monitoring result of the monitoring unit;
The modified region is formed inside the semiconductor object along a virtual plane facing the surface of the semiconductor object,
The semiconductor object heating apparatus, wherein the monitoring unit has a second observation unit that observes a hologram of a processing target area at a depth position corresponding to the virtual plane of the semiconductor object. 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 over the entire processing target region, the heating unit 6. The semiconductor object heating apparatus of claim 5 , wherein the heating is terminated. The control unit calculates the amplitude distribution of the processing target region based on the hologram observed by the second observation unit, and if the amplitude distribution cannot be obtained in the entire processing target region, the heating unit 7. The semiconductor object heating apparatus according to claim 5 or 6 , wherein the heating temperature is increased by increasing the heating temperature. a heating unit for heating a semiconductor object in which a modified region including a plurality of modified spots and a plurality of cracks extending from the plurality of modified spots and a gas are formed;
a monitoring unit for monitoring the crack in the semiconductor object being heated by the heating unit;
a control unit that controls the heating unit based on the monitoring result of the monitoring unit;
an unevenness measuring unit that measures unevenness of the surface of the semiconductor object heated by the heating unit ;
The control unit calculates a value related to the amount of distortion of the semiconductor object based on the measurement result of the unevenness measurement unit, and terminates heating by the heating unit when the value related to the amount of distortion exceeds a predetermined value . Semiconductor object heating device. 9. The semiconductor object heating apparatus according to claim 1, wherein said monitoring unit has a light source for illuminating said semiconductor object. 10. The semiconductor object heating apparatus according to claim 1 , wherein a plurality of said modified regions are formed so as to line up in a direction facing said surface.

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