JP2023124506A - Measurement device and laser processing device - Google Patents

Abstract

To improve productivity than before in a wafer manufacturing technology that obtains a wafer from an ingot by laser slicing.SOLUTION: A measurement device (36) for measuring ingot heights comprises a contact (361), a contact support unit (362a), a contact guide unit (363), a position detection unit (364), a contact lift unit (365b), and a lift unit drive device (368). The contact is extended along the height direction in the state of facing an ingot top face (21) along the height direction. The contact support unit fixedly supports the contact at a base end (361b). The contact guide unit guides the contact support unit so as to be slidable in the height direction. The position detection unit generates output that corresponds to the position of the contact in the height direction. The contact lift unit is disposed below the contact support unit so as to be contactable with the contact support unit. The lift unit drive device moves the contact lift unit up and down along the height direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to a measuring device that measures the height of an ingot and a laser processing device that irradiates an ingot with a laser beam.

Patent Literature 1 discloses a laser processing apparatus that irradiates a laser beam having a wavelength that is transmissive to the ingot from an end face of the ingot with a focal point positioned inside the ingot to form a peeling layer. This laser processing apparatus comprises holding means, laser beam irradiation means, imaging means, height detection means, and focal point positioning means. The holding means holds the ingot and moves in the end face direction parallel to the end face of the ingot. The laser beam irradiation means irradiates the ingot held by the holding means with a laser beam. The laser beam irradiating means has a condenser that moves the focal point in a direction perpendicular to the end face of the ingot irradiated with the laser beam. The imaging means detects the position of the ingot held by the holding means in the end face direction. The imaging means is attached to the tip corner of the frame with a gap in the X direction from the condenser arranged in the laser beam irradiation means. The height detection means detects the height of the end face of the ingot. The condensing point positioning means positions the condensing point of the concentrator at a position corresponding to the thickness of the wafer from the end face of the ingot, based on the detection value of the height detection means.

The imaging means includes an objective lens for imaging the position of the ingot held on the chuck table in the direction of the end surface, i.e., the outer shape, an imaging housing for holding the objective lens, and an image captured by the objective lens via the imaging housing. It has an imaging device through which light is guided, and a moving unit that moves the objective lens unit and the imaging device in the Z direction by moving the imaging housing in the Z direction, that is, in the vertical direction. The height detection means can be configured integrally with an imaging housing that constitutes the imaging means. The height detection means comprises a contact terminal, a case for holding the contact terminal, a spring incorporated in the case for pressing the contact terminal downward, and a switch provided at the upper end of the inner space of the case. A contact terminal is arranged adjacent to the imaging means. The lower side of the contact terminal, where the tip is formed, extends downward from the lower end surface of the case, and a flange portion that receives the pressing force of the spring is formed at a portion positioned within the internal space of the case. In addition, the switch is arranged at the upper end of the internal space of the case with a slight gap from the rear end portion positioned above the contact terminals in the normal state. The switch emits an ON signal and transmits it to the control means when the contact terminal moves upward in the case and the rear end comes into contact with the contact terminal.

In the laser processing apparatus disclosed in Patent Literature 1, the height position of the chuck table is detected using height detection means before the ingot is placed on the chuck table and processing is started. More specifically, first, the height detection means is moved together with the imaging means to a standby position where the tip of the contact terminal is positioned above the chuck table by a predetermined distance. Then, with the imaging means and the height detection means at the standby position, the movement means is operated to move the chuck table so that the center of the chuck table is immediately below the tip of the contact terminal of the height detection means. Let When the center of the chuck table is positioned directly below the tip, the driving motor of the moving section is operated to lower the height detection means. At this time, the tips of the contact terminals are lowered at a low speed so as not to abruptly collide with the chuck table and be damaged.

The contact terminals are pressed downward by springs disposed inside the case, and when the contact terminals descend and reach the chuck table, the contact terminals stop descending. After that, the switch descends by the gap set between the rear end of the contact terminal and the switch, and when it reaches the rear end, the switch generates an ON signal. When the ON signal is sent to the control means, a stop signal is immediately sent to the drive motor to stop the drive motor, and the lowering of the height detection means is also stopped.

When the control means receives an ON signal from the switch and the drive motor is stopped, the graduation of the scale is read by the detection terminal, and the position of the tip of the contact terminal is measured. The value read at this time is transmitted to the control means and stored as the height position of the chuck table. After the height position of the chuck table is detected and stored in this manner, the drive motor is driven to raise the height detection means and move it to the standby position.

After the height position of the chuck table is detected as described above and the height detection means is set to the standby position, the ingot is placed on the chuck table. After the ingot is placed on the chuck table, the same operation as the above-described operation for detecting the height of the chuck table is performed. That is, the height detection means is lowered toward the ingot placed on the chuck table, and the tip of the contact terminal is brought into contact with the upper end surface of the ingot. is detected and stored by the control means. Thus, if the height position of the chuck table and the height position of the end surface of the ingot are detected, the thickness of the ingot is calculated. The condensing point positioning means is operated to move the concentrator in the Z direction, and the position of the condensing point of the laser beam is adjusted to a predetermined depth position from the end surface of the ingot according to the thickness of the wafer to be peeled.

Japanese Patent No. 6831253

As described above, in the laser processing apparatus described in Patent Document 1, the height detection means moves the contact terminal relatively toward the switch due to contact between the tip portion of the contact terminal and the wafer end surface, and the rearward position of the contact terminal is detected. The height of the end surface of the ingot is detected by the contact of the end with the switch. Therefore, a detection error occurs due to the sensitive width of the switch. In addition, the descending speed of the height detection means must be slowed down so as not to damage the chuck table or the end face of the ingot, resulting in a longer cycle time and lower productivity. In addition, since the height position of the chuck table and the height position of the end surface of the ingot are detected only once, errors in the parallelism of the ingot and the depth of the focal point position from the end surface of the ingot and the table Influences such as errors in flatness cannot be eliminated, and this causes a large processing allowance during grinding, which is a factor in deteriorating the yield. Furthermore, it has been difficult to achieve both high speed, ie shortening of the cycle time, and high accuracy in adjusting the focal point position by means of the focal point positioning means. As described above, this type of conventional laser processing apparatus still has room for improvement from the viewpoint of improving productivity, including cycle time and yield. The present invention has been made in view of the circumstances exemplified above. That is, the present invention makes it possible, for example, to improve productivity in wafer manufacturing technology for obtaining wafers from ingots by so-called laser slicing.

A measuring device (36) according to claim 1 is a device for measuring an ingot height, which is the height of an ingot (2) to be processed by a laser processing device (30),
While facing the top face (21), which is one end face in the height direction of the ingot, along the height direction, the top face (21) can be brought into contact with the top face in the height direction. a contact (361) extending along;
The contact is fixedly supported at a base end (361b) opposite to a tip (361a) which is one end in the height direction of the contact and contacts the top surface. a child support (362a);
a contactor guide portion (363) for slidably guiding the contactor support portion along the height direction;
a position detector (364) that generates an output corresponding to the position of the contact or the contact support in the height direction;
a contact lifting portion (365b) disposed below the contact support portion so as to be able to contact the contact support portion;
a lift driving device (368) for moving the contact lift up and down along the height direction;
It has
6. The laser processing apparatus (30) according to claim 5, based on the ingot height measured by the measuring device, a laser beam having a transparency to the top surface for obtaining a wafer (1) from the ingot. An apparatus configured to emit a beam, comprising:
A concentrator (356) disposed opposite the top surface along the height direction such that irradiating the top surface with the laser beam causes the laser beam to be focused within the ingot. and,
a chuck (31) provided to support the ingot by joining with a bottom surface (22) that is the other end surface of the ingot in the height direction;
a chuck moving mechanism (32) provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction intersecting with the height direction;
an optical system (351) provided in a laser beam path (BL) between a transmitter (34), which is the source of the laser beam, and the collector;
an optics stage (352) that supports the optics;
a coarse movement mechanism (354) that vertically moves the optical system stage along the height direction;
By being fixed to the optical system stage, the light collector can be moved up and down relative to the optical system stage along the height direction while moving up and down together with the optical system stage by the coarse movement mechanism. a fine movement mechanism (357) provided to support the concentrator in
a control unit (37) that controls the operations of the coarse movement mechanism and the fine movement mechanism;
It has
The laser processing apparatus (30) according to claim 7 is a transmissive top surface (21) which is one end surface in the height direction of the ingot (2) to obtain the wafer (1) from the ingot (2). A device for irradiating a laser beam having
A concentrator (356) disposed opposite the top surface along the height direction such that irradiating the top surface with the laser beam causes the laser beam to be focused within the ingot. and,
a chuck (31) provided to support the ingot by joining with a bottom surface (22) that is the other end surface of the ingot in the height direction;
a chuck moving mechanism (32) provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction intersecting with the height direction;
an optical system (351) provided in a laser optical path between a transmitter (34), which is the source of the laser beam, and the condenser;
an optics stage (352) that supports the optics;
a coarse movement mechanism (354) that vertically moves the optical system stage along the height direction;
By being fixed to the optical system stage, the light collector can be moved up and down relative to the optical system stage along the height direction while moving up and down together with the optical system stage by the coarse movement mechanism. a fine movement mechanism (357) provided to support the concentrator in
a control unit (37) that controls the operations of the coarse movement mechanism and the fine movement mechanism;
It has

In addition, in each column of the application documents, each element may be given a reference sign with parentheses. In this case, the reference numerals indicate only one example of the corresponding relationship between the same element and the specific configuration described in the embodiment described later. Therefore, the present invention is not limited in any way by the description of the reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the outline|summary of the wafer manufacturing method using the laser processing apparatus which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows schematic structure of the laser processing apparatus which concerns on one Embodiment of this invention. FIG. 3 is a side view showing a schematic configuration of the measuring device according to one embodiment of the present invention shown in FIG. 2; FIG. 4 is a side view showing an overview of the operation of the measuring device shown in FIG. 3; It is a top view which expands and shows a part of laser processing apparatus which concerns on a modification. 6 is a plan view showing an overview of the operation of the configuration shown in FIG. 5; FIG.

(embodiment)
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described based on the drawings. It should be noted that if various modifications applicable to one embodiment are inserted in the middle of a series of explanations related to the embodiment, there is a risk that the understanding of the embodiment will be hindered. For this reason, the modification will not be inserted in the middle of the series of descriptions regarding the embodiment, and will be described collectively after that. In addition, the description of each drawing, and the corresponding description of the device configuration and its functions and operations that will be described below are simplified for the purpose of concisely describing the content of the present invention. It does not limit the content of the invention at all. For this reason, it goes without saying that each drawing and a drawing showing a specific configuration that is actually manufactured and sold do not always match. That is, unless the applicant explicitly limits the present invention by the prosecution history of the present application, the present invention is limited by the description of each drawing and the description of the device configuration and its functions and operations that will be described below correspondingly. It goes without saying that it should not be interpreted as

(Outline of wafer manufacturing)
Referring to FIG. 1, a wafer 1 is obtained by slicing an ingot 2 having a substantially cylindrical shape when viewed from the side, and is formed into a thin plate having a substantially circular shape when viewed from the top. That is, the wafer 1 has a substantially cylindrical end surface surrounding the central axis L. As shown in FIG. Similarly, the ingot 2 has a substantially cylindrical side surface surrounding the central axis L. As shown in FIG. The central axis L is an imaginary straight line that is parallel to the substantially cylindrical end surface of the wafer 1 and the substantially cylindrical side surface of the ingot 2 and that passes through the axial centers of the wafer 1 and the ingot 2 . From the viewpoint of simplification of illustration and explanation, the illustration and explanation of the so-called orientation flat which is usually provided on the wafer 1 and the ingot 2 are omitted in this specification.

To simplify the following description, right-handed XYZ coordinates are set as shown in the drawing for convenience. In such right-handed XYZ coordinates, the Z-axis is parallel to the central axis L and is the direction that defines the wafer thickness and ingot height. That is, the Z-axis direction corresponds to the thickness direction of the wafer 1 or the height direction of the ingot 2 . Also, the X-axis and the Y-axis are assumed to be parallel to the main surface of the wafer 1 and the end surface of the ingot 2 . A "principal surface" is a surface of a plate-like object such as the wafer 1, which is orthogonal to the plate thickness direction, and may also be referred to as "upper surface", "lower surface", "bottom surface", or "plate surface". A direction along the main surface of the wafer 1 or the end surface of the ingot 2, that is, any direction intersecting with the Z-axis direction may be hereinafter referred to as an “in-plane direction”. Typically, the main surface of the wafer 1 and the end surface of the ingot 2 are substantially horizontal surfaces that are substantially orthogonal to the Z-axis. Therefore, the "in-plane direction" is typically any direction orthogonal to the Z-axis. That is, in the following description, "in-plane direction" refers to any direction parallel to the XY plane.

The wafer 1 has a wafer front surface 11 and a wafer back surface 12 which are a pair of main surfaces. Similarly, the ingot 2 has an ingot top surface 21 and an ingot bottom surface 22 which are a pair of end surfaces. A wafer manufacturing method for obtaining a wafer 1 from an ingot 2 includes the following steps as main steps.

(1) Peeling layer forming step: While irradiating the ingot top face 21, which is one end face in the height direction of the ingot 2, with a laser beam B having a certain degree of transparency to the ingot 2, the laser beam B is irradiated. Move the position PR in the in-plane direction. As a result, a release layer 23 is formed at a depth corresponding to the thickness of the wafer 1 from the ingot top surface 21 . Here, the “predetermined level of transparency” is a level of transparency that enables formation of the focal point BP of the laser beam B at a depth corresponding to the thickness of the wafer 1 inside the ingot 2 . In addition, the "depth corresponding to the thickness of the wafer 1" is the thickness of the finished wafer 1 (that is, the target value of the thickness) plus the thickness corresponding to the predetermined processing allowance in the wafer flattening process, etc., which will be described later. , and may also be referred to as "a depth corresponding to the thickness of the wafer 1". The irradiation position PR of the laser beam B in the in-plane direction on the ingot top surface 21, which is the laser irradiation surface, is the scanning parallel to the X-axis direction, like the outward scanning Sc1 and the backward scanning Sc2 shown in FIG. It is scanned in direction Ds. Also, the irradiation position PR is index-fed in the line feed direction Df parallel to the Y-axis direction each time the scanning direction Ds is scanned once. Both the line feed direction Df and the scanning direction Ds are in-plane directions (that is, directions along the ingot top surface 21) and directions orthogonal to each other.

(2) Wafer peeling process: Wafer 1 is obtained by peeling wafer precursor 24 between ingot top surface 21 and peeling layer 23 from ingot 2 at peeling layer 23 . Immediately after peeling, the back surface 12 of the wafer has rough (that is, it requires grinding or polishing) unevenness due to peeling of the peeling layer 23 and the wafer peeling process.

(3) Wafer flattening step: Of the wafer front surface 11 and the wafer back surface 12, which are the main surfaces of the wafer 1, at least the peeling layer 23 and the wafer back surface 12 having unevenness caused by peeling in the wafer peeling step are flattened. A final wafer 1 having an epi-ready main surface is thus obtained. In the wafer flattening process, ECMG and ECMP can be used in addition to general grindstone polishing and CMP. CMP is an abbreviation for Chemical Mechanical Polishing. ECMG is an abbreviation for Electro-Chemical Mechanical Grinding. ECMP is an abbreviation for Electro-Chemical Mechanical Polishing. The wafer flattening process can be performed by using one of these selectable plural types of flattening processes alone or by appropriately combining a plurality of types.

(4) Ingot planarization process: The newly formed ingot top surface 21 after delamination of the wafer precursor 24 is rough (i.e., requires grinding or polishing) due to the delamination of the delamination layer 23 and the wafer delamination process. ) has unevenness. Therefore, the ingot top surface 21 is flattened, that is, mirror-finished so that the ingot 2 that has undergone the wafer peeling process can be reused in the peeling layer forming process. Also in the ingot flattening process, ECMG and ECMP can be used in addition to general grindstone polishing and CMP. The ingot planarization process can also be performed by using one of these selectable multiple types of planarization processes alone or by appropriately combining multiple types of planarization processes.

(laser processing equipment)
FIG. 2 shows a schematic configuration of a laser processing apparatus 30 used in the peeling layer forming process. That is, the laser processing apparatus 30 is configured to irradiate the ingot top face 21, which is one end face in the height direction of the ingot 2, with the laser beam B having transparency in order to obtain the wafer 1 from the ingot 2. It is Specifically, as shown in FIG. 2, the laser processing device 30 includes a chuck 31, a chuck moving mechanism 32, a support table 33, a transmitter 34, a laser irradiation device 35, and a measuring device 36. , and a control unit 37 . Each part constituting the laser processing apparatus 30 will be described in order below. It is assumed that the right-handed XYZ coordinates shown in FIG. 2 and subsequent figures are displayed so as to match the right-handed XYZ coordinates shown in FIG. In addition, in the present embodiment, the positive direction of the Z-axis indicates vertically upward. That is, the Z-axis negative direction is assumed to be the same or substantially the same direction as the gravity action direction. As for the measuring device 36, for the convenience of illustration and explanation, only the location in the Y-axis direction is indicated by a two-dot chain line rectangle in FIG. show.

(Chuck)
The chuck 31 is provided to support the ingot 2 with the ingot top surface 21 exposed upward by joining with the ingot bottom surface 22 which is the other end surface of the ingot 2 in the height direction. Specifically, the chuck 31 has a chuck surface 311 exposed upward when the ingot 2 is not supported. The chuck surface 311 to be bonded to the ingot bottom surface 22 has good flatness and is provided substantially parallel to the XY plane. The chuck 31 fixedly supports the ingot 2 on the chuck surface 311 by a well-known method (for example, suction by negative pressure, adhesion, etc.). The chuck 31 is fixedly supported on the upper surface of a chuck table 320 provided in the chuck moving mechanism 32 .

(chuck movement mechanism)
The chuck moving mechanism 32 is configured to be movable in the in-plane direction while supporting the chuck 31 in a fixed manner. Specifically, the chuck moving mechanism 32 includes a chuck table 320 , a first slide mechanism 321 , a second slide mechanism 322 , a first slide motor 323 and a second slide motor 324 . The chuck table 320 is formed in a plate shape having a plate thickness direction in the Z-axis direction, and fixedly supports the chuck 31 by screwing or the like on the main surface exposed upward. The first slide mechanism 321 is configured to reciprocate the chuck table 320 in the in-plane direction, that is, in the X-axis direction. The second slide mechanism 322 is configured to reciprocate the chuck table 320 in the in-plane direction, that is, in the Y-axis direction. Specifically, the first slide mechanism 321 and the second slide mechanism 322 each have a configuration as a so-called ball-screw-driven uniaxial stage. That is, the second slide mechanism 322 includes a pair of Y-axis slide rails 322a placed on the support base 33 while extending in the Y-axis direction, and a pair of Y-axis slide rails 322a slidably provided on the Y-axis slide rails 322a. and a Y-axis slider 322b. The first slide mechanism 321 is fixedly supported on the Y-axis slider 322b. The first slide motor 323 drives a ball screw (not shown) in the first slide mechanism 321 to reciprocate the chuck table 320 in the X-axis direction. The second slide motor 324 is provided so as to reciprocate the chuck table 320 together with the first slide mechanism 321 in the Y-axis direction by driving a ball screw (not shown) in the second slide mechanism 322 .

(support base)
A support table 33 forming a basic structure of the laser processing apparatus 30 has a surface plate portion 331 and a pedestal portion 332 . As the surface plate portion 331, for example, a stone surface plate that is less affected by deformation and dimensional changes due to temperature changes and has excellent physical and mechanical strength can be used. Such a stone platen may be formed of, for example, granite (ie, granite) or the like. The surface plate portion 331 is formed in a thick plate shape, and the horizontality of the upper and lower plate surfaces is precisely finished. The surface plate portion 331 is supported from below by a base portion 332 having a damping function. A chuck moving mechanism 32 , a laser irradiation device 35 , and a measuring device 36 are provided on the surface plate portion 331 .

(Laser irradiation device)
The laser irradiation device 35 is arranged on one side of the movable range of the chuck table 320 along the Y-axis direction by the second slide mechanism 322 (that is, on the Y-axis positive direction side in the configuration example shown in FIG. 2). there is The laser irradiation device 35 is configured to irradiate the ingot 2 held by the chuck 31 with the laser beam B output from the transmitter 34 which is the source of the laser beam B downward in the drawing. Specifically, the laser irradiation device 35 includes an optical system 351, an optical system stage 352, an optical system guide body 353, a stage moving mechanism 354, a stage position scale 355, a condenser 356, and a condenser. A moving mechanism 357 is provided.

The optical system 351 is provided in the laser light path BL between the transmitter 34 and the collector 356 . The optical system 351 includes various optical elements such as lenses and reflecting mirrors, a beam expander that expands the beam diameter of the laser beam B, a spatial light modulator that modulates the laser beam B, and the like. The optical system 351 is installed on the upper main surface of an optical system stage 352 which is made of a rigid material such as metal and has a plate-like shape with a plate thickness direction in the Z-axis direction. That is, the optical system stage 352 is provided so as to support the optical system 351 from below. The optical system stage 352 is provided with through holes through which a plurality of optical system guide bodies 353, which are rod-shaped members extending in the Z-axis direction, pass. The optical system guide member 353 is provided such that its lower end portion is supported on the support base 33 and its upper end portion penetrates the optical system stage 352 and protrudes upward by a predetermined amount. At least four optical system guide bodies 353 are arranged so as to be positioned on the corners or sides of the rectangle when viewed from above with a line of sight parallel to the Z-axis direction. The optical system stage 352 is provided so as to be vertically movable along the Z-axis direction while being guided by a plurality of optical system guide bodies 353 . A stage moving mechanism 354 as a coarse movement mechanism is a ball screw mechanism including a coarse movement motor 354a, and is configured to vertically move the optical system stage 352 along the Z-axis direction, that is, along the height direction of the ingot 2. . The stage position scale 355 has a configuration as a linear scale for detecting the position of the optical system stage 352 in the Z-axis direction.

The condenser 356 has an optical element such as an objective lens, and is configured to form a condensing point BP of the laser beam B at a predetermined lower position. That is, when the chuck table 320 reaches a predetermined processing area while the chuck 31 is supporting the ingot 2 , the light collector 356 irradiates the ingot top surface 21 with the laser beam B, thereby removing the ingot 2 . It is arranged to face the ingot top surface 21 along the height direction of the ingot 2 so that the laser beam B is condensed inside.

A condenser 356 is supported by the optical system stage 352 via a condenser moving mechanism 357 . That is, the collector 356 is fixed to the bottom surface of the collector moving mechanism 357 . A condensing device moving mechanism 357 is fixed to the optical system stage 352 . The collector movement mechanism 357 is a linear motion stage that expands and contracts in the Z-axis direction, and has a configuration as a piezo stage driven by, for example, a piezoelectric element. In this way, the light collector moving mechanism 357 as a fine movement mechanism is fixed to the optical system stage 352 and moves up and down together with the optical system stage 352 by the stage moving mechanism 354 as a coarse movement mechanism. is provided so as to support a light collector 356 so as to be vertically movable relative to the optical system stage 352 along the height direction of the ingot 2 .

(measuring device)
The measuring device 36 is a device for measuring the ingot height, which is the height of the ingot 2 to be processed by the laser processing device 30, and is movable along the Y-axis direction of the chuck table 320 by the second slide mechanism 322. It is arranged on the other side of the range (that is, on the Y-axis negative direction side in the configuration example shown in FIG. 2). That is, the laser irradiation device 35 and the measurement device 36 are provided adjacent to each other along the Y-axis direction. Then, based on the ingot height measured by the measuring device 36, the laser processing device 30 uses the laser irradiation device 35 to emit a laser beam B having transparency to the ingot top surface 21 in order to obtain the wafer 1 from the ingot 2. configured to irradiate.

A specific configuration of the measuring device 36 will be described below with reference to FIGS. 3 and 4 in addition to FIG. The measuring device 36 is supported by a support frame 360 which is fixedly supported by the support base 33 shown in FIG. The measuring device 36 includes a contactor 361 , a contactor holder 362 , a contactor movable stage 363 , a position detector 364 , an elevating member 365 , and a lifter elevating mechanism 366 .

The contactor 361 faces the ingot top surface 21 along the Z-axis direction, that is, along the height direction of the ingot 2 , and moves toward the ingot top surface 21 along the Z-axis direction so as to be able to contact the ingot top surface 21 . has been extended. Specifically, the contactor 361 has a tip end portion 361a that is one end portion in the extension direction, that is, the Z-axis direction and contacts the ingot top surface 21, and a base end portion 361b on the opposite side. The contactor 361 is fixedly supported by the contactor holder 362 at the proximal end portion 361b.

The contactor holder 362 is provided along the Z-axis so as to support the contactor support portion 362a that fixedly supports the base end portion 361b of the contactor 361 and the contactor support portion 362a in a cantilever manner. and a fixing portion 362b. In the contact holder 362, a flat plate-shaped contact support portion 362a having a plate thickness direction in the Z-axis direction extends from a flat plate-shaped fixing portion 362b having a plate thickness direction in the Y-axis direction toward the Y-axis negative direction. It is formed in a substantially L shape when viewed from the side. In this embodiment, the contactor 361 is fixed to the contactor support portion 362a by any fixing means such as screwing, adhesion, or welding. The fixed part 362b is attached to the contactor movable stage 363 so as to be reciprocally movable along the Z-axis direction. That is, the contactor movable stage 363 as a contactor guide portion is provided so as to slidably guide the contactor 361 along the Z-axis direction together with the contactor support portion 362a. The contactor 361 and the contactor holder 362 are guided by the contactor movable stage 363 while being urged toward the ingot top surface 21 by their own weight, so as to be slidable along the Z-axis direction. there is The position detection section 364 is provided to generate an output corresponding to the position of the contactor 361 or the contactor support section 362a in the Z-axis direction. Specifically, the position detection section 364 has a configuration as a linear scale attached to the fixed section 362b.

The lifting member 365 has a base plate portion 365a and a contactor lifting portion 365b. The base plate-like portion 365a is formed in a plate shape having a plate thickness direction in the Y-axis direction, and is supported by a lifting portion elevating mechanism 366 so as to be slidable along the Z-axis direction. The contact lifting portion 365b is arranged below the contact supporting portion 362a so as to be able to contact the contact supporting portion 362a. The contact lifting portion 365b is provided integrally with the base plate-shaped portion 365a and extends from the lower end portion of the base plate-shaped portion 365a in the Y-axis negative direction. As shown in FIG. 3, the contactor lifting portion 365b is positioned below the contactor supporting portion 362a in a measurement state in which the tip portion 361a of the contactor 361 is in contact with the ingot top surface 21. is separated from On the other hand, as shown in FIG. 4, the contactor lifting portion 365b supports the contactor in a non-measurement state in which the tip portion 361a of the contactor 361 is above the ingot top surface 21 and separated from the ingot top surface 21. By abutting against the portion 362a, the contact support portion 362a is supported from below.

In this embodiment, the contact lifting portion 365b has a side projecting portion 365c and a contact projecting portion 365d. The side protruding portion 365c is a plate-like portion having a plate thickness direction in the Z-axis direction, and the end portion on the Y-axis positive direction side is coupled to the lower end portion of the base plate-like portion 365a. The contact protrusion 365d protrudes upward from the lateral protrusion 365c. The contact protrusion 365d contacts the contact support portion 362a from below when the elevating member 365 moves upward as shown in FIG. 4 from the lowered position shown in FIG. It is arranged directly below the portion where the contactor 361 is not provided in the in-plane direction of the contactor support portion 362a.

The lifting portion elevating mechanism 366 is configured as a so-called ball-screw-driven uniaxial stage capable of reciprocating the elevating member 365 in the Z-axis direction. That is, the lifting portion lifting mechanism 366 includes a lifting portion sliding mechanism 367 and a lifting portion driving device 368 . The lifting portion slide mechanism 367 is a uniaxial slide stage having a slide rail and a slider, and the base plate portion 365a of the lifting member 365 is fixed to the slider portion. The lifting portion driving device 368 is a motor that drives a ball screw provided in the lifting portion lifting mechanism 366, and is provided to vertically move the lifting member 365, that is, the contactor lifting portion 365b along the Z-axis direction.

The buffer portion 369 is provided to absorb the impact when the tip portion 361a of the contactor 361 comes into contact with the ingot top surface 21 due to the descent of the contactor support portion 362a. Specifically, in this embodiment, the buffer portion 369 has a configuration as a counterbalance cylinder that expands and contracts along the Z-axis direction.

(control part)
Referring to FIG. 2 again, the control unit 37 is provided to control the overall operation of the laser processing device 30 . In this embodiment, the control unit 37 has a configuration as a so-called microcomputer including a processor and a memory. 30 to control the operation of each unit. "Memory" is a non-transitional physical storage medium such as ROM, magnetic disk, optical disk, flash memory, and the like. At least one processor and at least one memory are provided.

Specifically, the control unit 37 controls the operations of the first slide motor 323 and the second slide motor 324 in the chuck moving mechanism 32 to set the position of the chuck 31, that is, the ingot 2 within the XY plane to a desired position. It is designed to Also, the control unit 37 controls generation and stopping of the laser beam B in the transmitter 34 . Further, the control unit 37 controls the operation of each unit in the optical system 351 to adjust the beam shape of the laser beam B, the laser optical path BL, and the like. The control unit 37 also controls the operation of a stage moving mechanism 354, which is a coarse movement mechanism, to adjust the position of the optical system stage 352, that is, the optical system 351 in the Z-axis direction. The control unit 37 also controls the operation of a light collector moving mechanism 357, which is a fine movement mechanism, to adjust the relative position of the light collector 356 with respect to the optical system stage 352 in the Z-axis direction. Specifically, the control unit 37 controls the operation of the condenser movement mechanism 357 according to the positioning error of the stage movement mechanism 354 to adjust the height of the condenser 356, that is, the position in the Z-axis direction. It's like Further, the control unit 37 controls the operation of the measuring device 36 to measure the ingot height at a plurality of points in the in-plane direction of the ingot top surface 21, and based on the ingot height measured by the measuring device 36, The operation of the collector movement mechanism 357 is controlled each time the laser beam B is irradiated. Further, the control unit 37 controls the height of the chuck surface 311, which is the height of the chuck surface 311 measured in advance, for each irradiation of the laser beam B (that is, for each of the plurality of irradiation positions PR on the ingot top surface 21). It controls the operation of the collector moving mechanism 357 .

(motion)
Hereinafter, an overview of the operation of the laser processing apparatus 30 having the configuration described above will be described together with the effects achieved by the configuration with reference to the drawings.

First, the control unit 37 controls the operation of the second slide motor 324 in the chuck moving mechanism 32 to set the position of the chuck table 320 in the Y-axis direction within the measurement area as shown in FIG. do. In the measurement area, the ingot 2 fixed to the chuck 31 is positioned directly below the measurement device 36 . In this measurement area, the controller 37 controls the operation of the first slide motor 323 and the second slide motor 324 in the chuck moving mechanism 32, and controls the measurement device 36 to measure the ingot top surface 21 in the in-plane direction. Measure the ingot height at multiple points.

When starting to measure the height of the ingot, the measuring device 36 is initially in an initial non-measurement state, as shown in FIG. In the initial state, the elevating member 365 is raised to such an extent that the tip portion 361a of the contactor 361 is above the ingot top surface 21 and is separated from the ingot top surface 21, which is a non-measurement state. In the initial state, even if the chuck table 320 is driven in the X-axis direction or the Y-axis direction and the ingot 2 moves, there is a sufficient gap to the extent that the tip portion 361a of the contactor 361 and the ingot top surface 21 do not come into contact with each other. A state in which the elevating member 365 is lifted until it is formed. In this initial state, the contactor 361 and the contactor holder 362 are biased downward toward the ingot top surface 21 by their own weight, so that the contactor support portion 362a moves toward the contactor lift portion 365b, that is, the contact projection portion 365d. abut. That is, the contactor lifting portion 365b contacts the contactor support portion 362a in a non-measurement state in which the tip portion 361a of the contactor 361 is separated from the ingot top surface 21 above the ingot top surface 21, thereby supporting the contactor. It supports the portion 362a from below. When the elevating member 365 starts to descend from this initial position by the operation of the lifter elevating mechanism 366, the contactor 361 and the contactor holder 362 come into contact with the ingot top surface 21 at the tip 361a of the contactor 361. Until then, it descends together with the lifting member 365 while being supported from below by the contact lifting portion 365b.

The tip end portion 361a of the contactor 361, which is being lowered together with the contactor support portion 362a, abuts against the ingot top surface 21, thereby establishing a measurement state. The impact of the contact at this time is well mitigated by the buffer portion 369 . Further, even if the lifting member 365 is further lowered by the operation of the lifting portion lifting mechanism 366, the contactor 361 and the contactor holder 362 cannot be lowered further. Therefore, after the tip portion 361a of the contactor 361 comes into contact with the ingot top surface 21 and the measurement state is established, as shown in FIG. It is separated from the contact support portion 362a at the bottom. That is, contacts 361 and contact retainers 362 are “left behind” in the descent of lift member 365 .

As shown in FIG. 4, in the non-measurement state, that is, in a state in which the contactor lifting portion 365b supports the contactor support portion 362a while abutting from below, the lifting member 365 descends at a constant speed. , the output of the position detector 364 changes continuously. On the other hand, when the tip portion 361a of the contactor 361 comes into contact with the ingot top surface 21 and the measurement state is established, the continuous change of the output of the position detection section 364 as described above ends. However, at the moment of contact and immediately after that, there is a cushioning action by the cushioning portion 369, which is the counterbalance means. Therefore, the control unit 37 detects the position not at the moment when the tip portion 361a of the contactor 361 comes into contact with the ingot top surface 21 or immediately after that, but when the contactor lifting portion 365b is separated from the contactor support portion 362a by a predetermined distance. Based on the output of section 364, the ingot height is measured at one point in the in-plane direction.

After measuring the height of the ingot at one point in the in-plane direction, the control section 37 drives the lifting section lifting mechanism 366 to lift the lifting member 365 . When the lifting member 365 rises until the contact lifting portion 365b, that is, the contact protrusion 365d contacts the contact supporting portion 362a, the contact holder 362 and the contact 361 rise as the lifting member 365 rises. That is, the contacts 361 and contact holders 362 are “lifted” by the lifting member 365 which is being raised. Then, when the lifting member 365 and the contactor 361 are raised to the above-described initial state, the chuck table 320 is driven in the X-axis direction and/or the Y-axis direction by a predetermined amount. The contactor 361 faces the measurement point of .

Thus, according to the configuration of the present embodiment, the ingot height can be measured relatively quickly and accurately while suppressing damage to the ingot 2 (that is, the occurrence of scratches on the top surface 21 of the ingot, for example). will be That is, it is possible to measure the height of the ingot with higher accuracy than the optical method or the ultrasonic ranging method. Moreover, even if the descending speed of the contactor 361 is not slowed down, damage to the ingot 2 during measurement can be well suppressed. Therefore, according to the present embodiment, it is possible to improve the productivity in the wafer manufacturing technology for obtaining the wafer 1 from the ingot 2 by so-called laser slicing.

When the ingot height measurement is completed by measuring the ingot height at different positions in the in-plane direction of the ingot top surface 21, the control unit 37 causes the second slide motor 324 in the chuck moving mechanism 32 to operate. is controlled to set the position of the chuck table 320 in the Y-axis direction within the machining area. In the processing area, the ingot 2 fixed to the chuck 31 is positioned directly below the collector 356 . Then, the control unit 37 irradiates the ingot top surface 21 with the laser beam B while controlling the depth of the condensing point BP from the ingot top surface 21 based on the measurement result of the ingot height. to form FIG. 1 shows how the ingot 2 is irradiated with the laser beam B and scanned. In addition, since this illustration shows the relative movement of the collector 356 and the irradiation position PR with respect to the ingot 2, it seems that the collector 356 and the irradiation position PR are moving in the XY directions. , in the laser processing apparatus 30, the concentrator 356, that is, the irradiation position PR is stationary in the XY directions, while the ingot 2 is moved in the XY directions by the chuck moving mechanism 32. FIG. As shown in FIG. 1, forward scanning Sc1 in which the light collector 356 moves relative to the ingot 2 in a first direction parallel to the X axis, and the light collector 356 moves to the ingot 2 along the X axis Inward scanning Sc2, which is parallel and relatively moves in a second direction opposite to the first direction, is alternately repeated. Index feeding is performed in which the chuck table 320 is fed by a predetermined small amount in the Y-axis direction between the forward scanning Sc1 and the backward scanning Sc2. The irradiation of the laser beam B is performed intermittently within the region of the ingot top surface 21 during at least one of the outward scanning Sc1 and the backward scanning Sc2. That is, multiple irradiations of the laser beam B are performed during the outward scanning Sc1 and/or the backward scanning Sc2. The scanning of the laser beam B during one forward scanning Sc1 or one backward scanning Sc2 is hereinafter referred to as "laser scanning".

Here, vibration in the height direction becomes a problem when increasing the processing speed (for example, 500 mm/s, 0.5 G acceleration/deceleration, etc.). In this regard, providing a vertical setup (that is, position adjustment in the Z-axis direction) mechanism on the side of the chuck table 320 may promote such vibration. Therefore, in this embodiment, the upper and lower setup mechanism is provided not on the chuck table 320 side but on the irradiation side of the laser beam B, that is, on the collector 356 side. Such a vertical setup mechanism normally requires a vertical setup stroke of about 50 mm. Further, in recent years, due to the increase in size of the optical system 351, the inertia in the upper and lower setup mechanism is increasing. For this reason, in the prior art, due to the large stroke and large inertia in the upper and lower setup mechanism, it is difficult to precisely control the depth of the focal point BP from the ingot top surface 21 (for example, at the submicron level). , it was difficult to control the focus position in real time. As a result, the processing allowance for polishing and grinding in the wafer flattening process increases, leading to deterioration in material yield in wafer manufacturing. In particular, in the method described in Patent Document 1, which uses the measured value of only one central point in the in-plane direction of the ingot 2 or the average value of the detected values of a plurality of points, the parallelism of the ingot 2 and the straightness of the stage could not negate the effect of

Therefore, in the configuration according to the present embodiment, the stage moving mechanism 354, which is a coarse movement mechanism with a large stroke and high inertia, performs rough up-and-down setup, and the concentrator movement mechanism 357, which is a fine movement mechanism with a small stroke and low inertia, is used. Precise upper and lower setup. Here, by using, for example, a so-called piezo stage as the condenser moving mechanism 357, it is possible to perform the upper and lower setup at a resolution of 10 nm level at high speed. In addition, not the average value of the ingot height measured at multiple points in the in-plane direction of the ingot top surface 21, but the measured value at each point is reflected in the precise and high-speed setup by the collector moving mechanism 357. By doing so, it is possible to precisely control the depth of the focal point BP from the ingot top surface 21 for each irradiation of the laser beam B in real time. As a result, the processing allowance for polishing and grinding in the wafer flattening process can be favorably reduced. Therefore, according to the present embodiment, it is possible to improve the productivity in the wafer manufacturing technology for obtaining the wafer 1 from the ingot 2 by so-called laser slicing.

As described above, since the position of the light collector 356 is fixed in the XY directions, the chuck moving mechanism 32 for moving the ingot 2 relative to the light collector 356 in the XY directions has at least an outer surface of the ingot 2 . A stroke larger than the diameter is required. The same applies to the measuring device 36 as well. Therefore, in practice, a stroke of at least twice the outer diameter of the ingot 2 or more is required. Therefore, the straightness error in the chuck moving mechanism 32 becomes a problem. That is, if the release layer 23 is tilted or the depth of the focal point BP from the ingot top surface 21 is distorted due to the straightness error in the chuck moving mechanism 32, polishing or grinding in the wafer flattening process may occur. processing allowance increases, leading to a deterioration in material yield in wafer manufacturing. A straightness error in the chuck moving mechanism 32 is reflected in the flatness of the chuck surface 311 . Furthermore, the flatness of the chuck surface 311 is also affected by dimensional errors during manufacture of the chuck 31 .

Therefore, in the configuration according to this embodiment, the chuck surface height, which is the height of the chuck surface 311 , is measured in advance, and the measured value of the chuck surface height is used as the Z axis of the light collector 356 by the light collector movement mechanism 357 . Reflected in axial position control. That is, the controller 37 controls the collector moving mechanism 357 each time the laser beam B is irradiated based on the chuck surface height measured in advance. As a result, the processing allowance for polishing and grinding in the wafer flattening process can be favorably reduced, thereby further improving productivity as compared with the prior art. The chuck surface height can be measured by, for example, a height measuring device (not shown) fixed to the collector movement mechanism 357 together with the collector 356 . Alternatively, the chuck surface height can be adjusted, for example, if the distance in the Y-axis direction between the measurement area and the machining area is sufficiently small to the extent that the influence of the straightness of the Y-axis slide rail 322a can be ignored to some extent. , can be measured using the measuring device 36 .

Although the target value of the stage moving mechanism 354, which is a coarse movement mechanism, is determined based on the precise measurement results, the deviation is not always zero due to the positioning command. Therefore, in the configuration according to this embodiment, the controller 37 controls the collector moving mechanism 357 according to the positioning error of the stage moving mechanism 354 . That is, the control unit 37 corrects the positioning error of the stage moving mechanism 354, which is a coarse movement mechanism, by the light collector moving mechanism 357, which is a fine movement mechanism. Specifically, for example, the control unit 37 refers to the output of the stage position scale 355 and controls the driving of the coarse movement motor 354a, which is a servo motor. Then, the controller 37 returns the accumulated pulse error to the collector moving mechanism 357 as a correction value. This makes it possible to control the depth of the condensing point BP from the ingot top surface 21 with high accuracy, thereby further improving productivity as compared with the prior art.

(Modification)
The present invention is not limited to the above embodiments. Therefore, the above embodiment can be modified as appropriate. A representative modified example will be described below. In the following description of the modified example, differences from the above embodiment will be mainly described. Moreover, in the above-described embodiment and modifications, the same reference numerals are given to parts that are the same or equivalent to each other. Therefore, in the description of the modification below, the description in the above embodiment can be used as appropriate for components having the same reference numerals as those in the above embodiment, unless there is a technical contradiction or special additional description.

The present invention is not limited to the specific configurations shown in the above embodiments. For example, the Z-axis positive direction does not have to be vertically upward. That is, the Z-axis positive direction may be a direction that intersects the vertically upward direction, which is the direction opposite to the direction in which gravity acts.

The first slide mechanism 321 may be configured to move the chuck table 320 in two XY directions. That is, unlike the second slide mechanism 322 as a coarse movement mechanism capable of moving the chuck table 320 in the Y-axis direction over a relatively long distance, the first slide mechanism 322 has a relatively short movable range of about the outer diameter of the ingot 2 . The slide mechanism 321 may be provided with a function as a fine movement mechanism in the Y-axis direction. As a result, the feeding amount of the chuck table 320, that is, the ingot 2 in the Y-axis direction during measurement by the measuring device 36 and processing by the laser irradiation device 35 can be controlled more precisely.

The types of motors such as the first slide motor 323, the second slide motor 324, the coarse motion motor 354a, etc. are not particularly limited. Thus, for example, linear motors can be used.

The contactor 361 may be seamlessly and integrally formed of the same material as the contactor support portion 362a. That is, the contactor 361 may be a protrusion formed on the contactor support portion 362a.

The contact protrusion 365d may be formed seamlessly and integrally from the same material as the lateral protrusion 365c. That is, the contact protrusion 365d may be a protrusion formed on the side protrusion 365c. Alternatively, the abutment protrusion 365d may be omitted. In other words, the contactor lifting portion 365b may be composed only of the side protruding portion 365c.

The lifting portion elevating mechanism 366 is not limited to a ball screw structure, and may be a fluid pressure cylinder or the like.

The cushioning portion 369 is not limited to the counterbalance cylinder, and may be configured using, for example, a spring, elastomer rubber (eg, silicone rubber), or the like.

The depth of the focal point BP from the ingot top surface 21 may fluctuate due to thermal elongation that accompanies the temperature rise during laser processing. Therefore, as shown in FIGS. 5 and 6, a reference block 381 is provided on the side of the chuck 31, and the distance between the reference surface 381a, which is the top surface of the reference block 381, and the condenser moving mechanism 357 is It is possible to implement a function of correcting thermal elongation by measuring with the length measuring sensor 382 at any time. The reference block 381 can be made of, for example, a material with a small coefficient of thermal expansion (for example, stone material constituting a stone surface plate). The reference block 381 is fixedly supported by the chuck table 320 by being attached to the chuck surface 311 or the upper surface of the chuck table 320 by adhesion or the like. Length measuring sensor 382 has a known contact or non-contact configuration to measure the reference block height, which is the height of reference block 381 or reference surface 381a, and collects together with collector 356. It is fixed to the optical device moving mechanism 357 .

In such a configuration, the length measurement sensor 382 measures the reference block height multiple times during a series of laser processing to obtain one wafer 1 . Then, the controller 37 controls the collector moving mechanism 357 appropriately according to the measured reference block height. Specifically, for example, after the chuck table 320 moves from the measurement area to the processing area, the control unit 37 controls that the reference surface 381a is set to the length measurement sensor as shown in FIG. 6 before laser processing is started. The chuck table 320 is moved to the length measurement position located directly below 382 to measure the height of the reference block. Then, after performing laser processing for a predetermined number of times or for a predetermined period of time, the control unit 37 moves the chuck table 320 to the length measurement position, re-measures the height of the reference block, and measures the height of the reference block measured before processing. is used as a reference value, and the change from the reference value is reflected in the correction of the collector moving mechanism 357 as the amount of thermal expansion. Re-measurement may be performed at predetermined times of laser scanning or at predetermined time intervals.

By configuring the laser processing apparatus 30 so that different positions in the in-plane direction of the top surface 21 of the ingot can be irradiated with the laser beam B during one laser scan, the cycle time can be favorably shortened, and the productivity can be improved. improve even further. Therefore, the laser processing apparatus 30 includes a plurality of optical systems 351, and is configured to irradiate the laser beam B that has passed through each of the plurality of optical systems 351 to different positions in the ingot top surface 21 in the in-plane direction. may be Specifically, for example, the laser beam B emitted from the common transmitter 34 is split into two by a beam splitter, and each passes through each of the two optical systems 351 and passes through each of the two condensers 356. can irradiate the ingot top surface 21 from. In this case, the condensers 356 may be provided in the same number as the optical systems 351 as described above, or the plurality of optical systems 351 may introduce the laser beam B into the same condenser 356 , that is, in common. may be configured to Alternatively, the laser beam B may be split into a plurality of beams by a diffractive optical element provided inside the condenser 356, as described in Japanese Patent Application Laid-Open No. 2016-225536, for example.

In the above description, the plurality of constituent elements that are seamlessly integrated with each other may be formed by bonding separate members together. Similarly, a plurality of constituent elements that are formed by bonding separate members together may be formed seamlessly and integrally with each other. Moreover, in the above description, the plurality of constituent elements that are made of the same material may be made of different materials. Similarly, a plurality of components made of different materials may be made of the same material.

Needless to say, the elements constituting the above-described embodiments are not necessarily essential, unless explicitly stated as essential or clearly considered essential in principle. In addition, when numerical values such as the number, amount, range, etc. of a constituent element are mentioned, unless it is explicitly stated that it is particularly essential, or when it is clearly limited to a specific numerical value in principle, the specific numerical value The present invention is not limited to Similarly, when the shape, direction, positional relationship, etc. of the constituent elements, etc. are mentioned, unless it is explicitly stated that it is particularly essential, or when it is limited to a specific shape, direction, positional relationship, etc. in principle , the shape, direction, positional relationship, etc., of which the present invention is not limited.

Modifications are also not limited to the above examples. In addition, multiple modifications can be combined with each other as long as they are not technically inconsistent.

2 ingot 36 measuring device 361 contactor 361a tip portion 361b base end portion 362a contactor support portion 363 contactor movable stage (contactor guide portion)
364 Position detector 365b Contactor lifting part 368 Lifting part driving device

Claims (11)

A measuring device (36) for measuring an ingot height, which is the height of an ingot (2) to be processed by a laser processing device (30),
While facing the top face (21), which is one end face in the height direction of the ingot, along the height direction, the top face (21) can be brought into contact with the top face in the height direction. a contact (361) extending along;
The contact is fixedly supported at a base end (361b) opposite to a tip (361a) which is one end in the height direction of the contact and contacts the top surface. a child support (362a);
a contactor guide portion (363) for slidably guiding the contactor support portion along the height direction;
a position detector (364) that generates an output corresponding to the position of the contact or the contact support in the height direction;
a contact lifting portion (365b) disposed below the contact support portion so as to be able to contact the contact support portion;
a lift driving device (368) for moving the contact lift up and down along the height direction;
measuring device with The contact and the contact support are slidable along the height direction while being biased toward the top surface by their own weight,
The contact lifting part is
supporting the contactor support from below by contacting the contactor support in a non-measurement state in which the tip of the contactor is separated from the top surface above the top surface;
provided so as to be separated from the contact support portion below the contact support portion in a measurement state in which the tip portion of the contact is in contact with the top surface,
The measuring device according to claim 1. Further comprising a cushioning portion (369) provided to reduce impact when the tip portion of the contact comes into contact with the top surface due to the descent of the contact support,
3. The measuring device according to claim 1 or 2. The buffer section includes a counterbalance cylinder that expands and contracts along the height direction,
The measuring device according to claim 3. A measuring device according to any one of claims 1 to 4, wherein the height of the ingot measured by such measuring device is transmitted to the top surface for obtaining wafers (1) from the ingot. A laser processing device (30) configured to irradiate a laser beam having a property of
A concentrator (356) disposed opposite the top surface along the height direction such that irradiating the top surface with the laser beam causes the laser beam to be focused within the ingot. and,
a chuck (31) provided to support the ingot by joining with a bottom surface (22) that is the other end surface of the ingot in the height direction;
a chuck moving mechanism (32) provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction intersecting with the height direction;
an optical system (351) provided in a laser beam path (BL) between a transmitter (34), which is the source of the laser beam, and the collector;
an optics stage (352) that supports the optics;
a coarse movement mechanism (354) that vertically moves the optical system stage along the height direction;
By being fixed to the optical system stage, the light collector can be moved up and down relative to the optical system stage along the height direction while moving up and down together with the optical system stage by the coarse movement mechanism. a fine movement mechanism (357) provided to support the concentrator in
a control unit (37) that controls the operations of the coarse movement mechanism and the fine movement mechanism;
laser processing equipment. The measuring device measures the height of the ingot at a plurality of points in the in-plane direction,
The control unit controls the fine movement mechanism for each irradiation of the laser beam based on the height of the ingot measured by the measuring device.
The laser processing apparatus according to claim 5. A laser processing apparatus (30) for irradiating a top face (21), which is one end face in the height direction of the ingot (2), with a laser beam having transparency in order to obtain the wafer (1) from the ingot (2). and
A concentrator (356) disposed opposite the top surface along the height direction such that irradiating the top surface with the laser beam causes the laser beam to be focused within the ingot. and,
a chuck (31) provided to support the ingot by joining with a bottom surface (22) that is the other end surface of the ingot in the height direction;
a chuck moving mechanism (32) provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction intersecting with the height direction;
an optical system (351) provided in a laser beam path (BL) between a transmitter (34), which is the source of the laser beam, and the collector;
an optics stage (352) that supports the optics;
a coarse movement mechanism (354) that vertically moves the optical system stage along the height direction;
By being fixed to the optical system stage, the light collector can be moved up and down relative to the optical system stage along the height direction while moving up and down together with the optical system stage by the coarse movement mechanism. a fine movement mechanism (357) provided to support the concentrator in
a control unit (37) that controls the operations of the coarse movement mechanism and the fine movement mechanism;
laser processing equipment. The control unit controls the fine movement mechanism each time the laser beam is irradiated, based on a pre-measured chuck surface height, which is the height of the surface (311) of the chuck bonded to the bottom surface.
The laser processing apparatus according to any one of claims 5-7. The control unit controls the fine movement mechanism according to a positioning error of the coarse movement mechanism.
The laser processing apparatus according to any one of claims 5-8. a reference block (381) fixedly supported by the chuck table;
a length measuring sensor (382) fixed to the fine movement mechanism to measure a reference block height, which is the height of the reference block;
further comprising
the length measurement sensor measures the height of the reference block multiple times during a series of laser processing to obtain one wafer;
The control unit controls the fine movement mechanism according to the measured reference block height.
The laser processing apparatus according to any one of claims 5-9. comprising a plurality of the optical systems,
configured to irradiate different positions on the top surface with the laser beam that has passed through each of the plurality of optical systems,
The laser processing apparatus according to any one of claims 5-10.

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