Measuring device and laser processing device

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

[Technical field]

[0001] 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. [Background technology]

[0002] Patent Document 1 discloses a laser processing device that irradiates an ingot with a laser beam having a wavelength that is transparent to the ingot from the end face of the ingot, positioning a focal point inside the ingot, to form a peeling layer. This laser processing device is composed of a holding means, a laser beam irradiating means, an imaging means, a height detection means, and a focal point positioning means. The holding means holds the ingot and moves in an end face direction parallel to the end face of the ingot. The laser beam irradiating means irradiates the ingot held by the holding means with a laser beam. The laser beam irradiating means includes a condenser that moves a focal point in a direction perpendicular to the end face of the ingot to be 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 at a distance in the X direction from the condenser disposed in the laser beam irradiating means. The height detection means detects the height of the end face of the ingot. The focal point positioning means positions the focal point of the collector at a position corresponding to the thickness of the wafer from the end face of the ingot based on the value detected by the height detection means.

[0003] The imaging means includes an objective lens unit for imaging the position in the end face direction of the ingot held on the chuck table, i.e., the outer shape, an imaging housing for holding the objective lens unit, an imaging element to which light captured by the objective lens unit is guided through the imaging housing, and a moving section for moving the imaging housing in the Z direction, i.e., the up-down direction, to move the objective lens unit and the imaging element in the Z direction. The height detection means can be integrally formed with the imaging housing constituting the imaging means. The height detection means is composed of a contact terminal, a case for holding the contact terminal, a spring built into the case for pressing the contact terminal downward, and a switch disposed at the upper end of the internal space of the case, and the contact terminal is disposed adjacent to the imaging means. The lower side of the contact terminal, where the tip portion 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 located within the internal space of the case. In addition, a switch is disposed at the upper end of the internal space of the case with a slight gap from the rear end portion located above the contact terminal in a steady state. The switch generates an ON signal when the contact terminal moves upward inside the case and the rear end comes into contact with it, and transmits the ON signal to the control means.

[0004] In the laser processing device described in Patent Document 1, before placing an ingot on the chuck table and starting processing, the height position of the chuck table is detected using a height detection means. 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 a predetermined distance above the chuck table. Next, while the imaging means and the height detection means are in the standby position, the moving means is operated to move the chuck table so that the center of the chuck table is directly below the tip of the contact terminal of the height detection means. When the center of the chuck table is positioned directly below the tip, the drive motor of the moving unit is operated to lower the height detection means. At this time, the tip of the contact terminal is lowered at a low speed so that it does not suddenly collide with the chuck table and cause damage, etc.

[0005] The contact terminal is pressed downward by a spring disposed inside the case, and when the contact terminal descends and reaches the chuck table, the descending of the contact terminal stops.The switch then descends by the amount of the gap set between the rear end of the contact terminal and the switch, and when the rear end is reached, an ON signal is generated from the switch.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 descent of the height detection means also stops.

[0006] When the control means receives an ON signal from the switch and stops the drive motor, the graduations on the scale are read by the detection terminal to measure the position of the tip of the contact terminal. The value read at this time is sent to the control means and stored as the height position of the chuck table. Once the height position of the chuck table has been detected and stored in this manner, the drive motor is driven to raise the height detection means and move it to the standby position described above.

[0007] As described above, when the height position of the chuck table is detected and the height detection means is set to the standby position, the ingot is placed on the chuck table. When the ingot is placed on the chuck table, the same operation as the operation of detecting the height of the chuck table described above 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 face of the ingot, and the position of the tip of the contact terminal, i.e., the height position of the end face of the ingot, is detected and stored in the control means. In this way, when the height position of the chuck table and the height position of the end face of the ingot are detected, the thickness of the ingot is calculated. The focal point positioning means is operated to move the condenser in the Z direction, and the focal point position of the laser beam is adjusted to a predetermined depth position from the end face of the ingot in accordance with the thickness of the wafer to be peeled. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6831253 Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, in the laser processing device described in Patent Document 1, the height detection means detects the height of the end face of the ingot by the contact between the tip of the contact terminal and the end face of the wafer, the contact terminal moves toward the switch relative to the switch, and the rear end of the contact terminal abuts against the switch. This causes a detection error due to the width of the switch's sensitivity. In addition, the lowering speed of the height detection means needs to be slowed down so as not to scratch the chuck table or the end face of the ingot, which lengthens the cycle time and reduces productivity. In addition, since the height position of the chuck table and the height position of the end face of the ingot are detected only once, the effects of errors in the parallelism of the ingot and errors in the flatness of the table on the depth of the focal point position from the end face of the ingot cannot be completely eliminated, which causes the processing allowance during grinding to increase and the yield to deteriorate. Furthermore, it was difficult to achieve both high speed, i.e., shortening the cycle time, and high accuracy in adjusting the focal point position by the focal point positioning means. As described above, in this type of conventional laser processing device, there is still room for improvement in terms of improving productivity, including cycle time and yield. The present invention has been made in consideration of the above-mentioned circumstances, etc. That is, the present invention makes it possible to improve productivity compared to the conventional technology in wafer manufacturing technology in which wafers are obtained from an ingot by so-called laser slicing, for example. [Means for solving the problem]

[0010] The measuring device (36) according to claim 1 is a device for measuring an ingot height, which is a height of an ingot (2) to be processed by a laser processing device (30), a contact (361) extending along the height direction toward a top surface (21), which is an end surface on one side in the height direction of the ingot, in a state facing the top surface along the height direction so as to be able to abut against the top surface; a contact support portion (362a) for fixedly supporting the contact at a base end portion (361b) opposite to a tip end portion (361a) that abuts against the top surface, the base end portion (361b) being one end portion of the contact in the height direction; A contact guide portion (363) that guides the contact support portion slidably along the height direction; a position detection unit (364) that generates an output corresponding to a position in the height direction of the contact or the contact support part; a contact holder (365b) disposed below the contact support portion so as to be capable of coming into contact with the contact support portion; A lifting part driving device (368) that moves the contact holding part up and down along the height direction; a buffer portion (369) provided to absorb an impact when the tip portion of the contact abuts against the top surface due to the lowering of the contact support portion; Equipped with picture, The buffer unit includes a counterbalance cylinder that expands and contracts along the height direction. is. The laser processing apparatus (30) according to claim 3 is an apparatus configured to irradiate the top surface of the ingot with a laser beam having transparency to obtain a wafer (1) from the ingot based on the ingot height measured by the measuring device, a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by being joined to a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path (BL) between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) that supports the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; a control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with The control unit is adapted to control the fine movement mechanism in accordance with a positioning error of the coarse movement mechanism. The laser processing apparatus (30) according to claim 5 is an apparatus configured to irradiate the top surface of the ingot with a laser beam having transparency to obtain a wafer (1) from the ingot based on the ingot height measured by the measuring device, a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by being joined to a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path (BL) between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) that supports the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; A reference block (381) fixedly supported by the chuck table; a length measuring sensor (382) fixed to the fine movement mechanism so as to measure a reference block height, which is the height of the reference block; a control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with picture, The length measuring sensor measures the height of the reference block a plurality of times during a series of laser processing steps for obtaining one of the wafers, The control unit controls the fine movement mechanism in accordance with the measured reference block height. There are. Claim to 10 The laser processing apparatus (30) described herein is an apparatus for irradiating a laser beam having transparency onto a top surface (21), which is an end surface on one side in a height direction of an ingot (2), in order to obtain a wafer (1) from the ingot, and a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by being joined to a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) that supports the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; a control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with picture, The control unit controls the fine movement mechanism in accordance with a positioning error of the coarse movement mechanism. There are. The laser processing apparatus (30) according to claim 12 is an apparatus for irradiating a laser beam having transparency onto a top surface (21) of an ingot (2), which is an end surface on one side in a height direction of the ingot, in order to obtain a wafer (1) from the ingot, a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by being joined to a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) that supports the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; A reference block (381) fixedly supported by the chuck table; a length measuring sensor (382) fixed to the fine movement mechanism so as to measure a reference block height, which is the height of the reference block; a control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with The length measuring sensor measures the height of the reference block a plurality of times during a series of laser processing steps for obtaining one of the wafers, The control unit is adapted to control the fine movement mechanism in accordance with the measured reference block height.

[0011] In addition, in each section of the application documents, each element may be given a reference symbol in parentheses. In this case, the reference symbol merely indicates an example of the correspondence between the 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 symbol. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing an overview of a wafer manufacturing method using a laser processing apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a side view showing a schematic configuration of a laser processing apparatus according to an embodiment of the present invention. [Diagram 3] 3 is a side view showing a schematic configuration of the measurement device according to the embodiment of the present invention shown in FIG. 2. [Figure 4] FIG. 4 is a side view showing an outline of the operation of the measuring device shown in FIG. 3. [Diagram 5] FIG. 13 is an enlarged plan view showing a portion of the laser processing apparatus according to one modified example. [Figure 6] FIG. 6 is a plan view showing an overview of the operation of the configuration shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Embodiment) Hereinafter, an embodiment of the present invention will be described based on the drawings. Note that, if various modified examples applicable to one embodiment are inserted in the middle of a series of explanations regarding the embodiment, understanding of the embodiment may be hindered. For this reason, the modified examples are not inserted in the middle of a series of explanations regarding the embodiment, but are explained together after that. In addition, the description of each drawing and the description of the device configuration and its functions and operations described below corresponding thereto are simplified to briefly explain the contents of the present invention, and do not limit the contents of the present invention in any way. For this reason, it goes without saying that each drawing does not necessarily match a diagram showing a specific configuration that is actually manufactured and sold. In other words, it goes without saying that the present invention should not be interpreted as being limited by the description of each drawing and the description of the device configuration and its functions and operations described below corresponding thereto, unless the applicant explicitly limits it through the prosecution history of this application.

[0014] (Wafer Manufacturing Overview) Referring to FIG. 1, the wafer 1 is obtained by slicing an ingot 2 that is substantially cylindrical in side view, and is formed in a substantially circular thin plate shape in plan view. That is, the wafer 1 has a substantially cylindrical end face surrounding a central axis L. Similarly, the ingot 2 has a substantially cylindrical side face surrounding the central axis L. The central axis L is a virtual straight line that is parallel to the substantially cylindrical end face of the wafer 1 and the substantially cylindrical side face of the ingot 2, and passes through the axial center of the wafer 1 and the ingot 2. Note that, from the viewpoint of simplifying the illustration and explanation, the so-called orientation flat that is usually provided on the wafer 1 and the ingot 2 is not illustrated or explained in this specification.

[0015] In order to simplify the following description, the right-handed XYZ coordinate system is set as shown in the figure for convenience. In such right-handed XYZ coordinate system, the Z axis is parallel to the central axis L and is a 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. The X axis and the Y axis are parallel to the main surface of the wafer 1 and the end face of the ingot 2. The "main surface" is a surface that is perpendicular to the plate thickness direction of a plate-like object such as the wafer 1, and may also be called the "upper surface", "lower surface", "bottom surface", or "plate surface". The direction along the main surface of the wafer 1 or the end face of the ingot 2, that is, any direction that intersects with the Z axis direction, may be referred to as the "in-plane direction" hereinafter. Typically, the main surface of the wafer 1 or the end face of the ingot 2 is a nearly horizontal surface that is substantially perpendicular to the Z axis. For this reason, the "in-plane direction" is typically any direction perpendicular to the Z axis. That is, in the following description, the "in-plane direction" refers to any direction parallel to the XY plane.

[0016] The wafer 1 has a pair of main surfaces, that is, a wafer front surface 11 and a wafer back surface 12. Similarly, the ingot 2 has a pair of end surfaces, that is, an ingot top surface 21 and an ingot bottom surface 22. A wafer manufacturing method for obtaining the wafer 1 from the ingot 2 includes the following steps as main processes.

[0017] (1) Peeling layer forming process: A laser beam B having a predetermined degree of transparency to the ingot 2 is irradiated onto the ingot top surface 21, which is an end surface on one side in the height direction of the ingot 2, while moving the irradiation position PR of the laser beam B in the in-plane direction. As a result, a peeling layer 23 is formed at a depth corresponding to the thickness of the wafer 1 from the ingot top surface 21. Here, the "predetermined degree of transparency" refers to a degree of transparency that allows the focal point BP of the laser beam B to be formed 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 a dimension obtained by adding a thickness corresponding to a predetermined processing margin in a wafer flattening process or the like described later to the thickness of the wafer 1, which is the finished product (i.e., the target thickness value), and may also be referred to as the "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 scanned in a scanning direction Ds parallel to the X-axis direction, as in the forward scanning Sc1 and the return scanning Sc2 shown in FIG. 1. Moreover, the irradiation position PR is index-fed in a line feed direction Df parallel to the Y-axis direction every time the irradiation position PR is scanned once in the scanning direction Ds. The line feed direction Df and the scanning direction Ds are both in-plane directions (i.e., directions along the ingot top surface 21) and are perpendicular to each other.

[0018] (2) Wafer peeling step: The wafer precursor 24, which is the portion between the ingot top surface 21 and the peeling layer 23, is peeled off from the ingot 2 at the peeling layer 23 to obtain the wafer 1. The wafer back surface 12 immediately after peeling has rough irregularities (i.e., to the extent that grinding or polishing is required) caused by the peeling layer 23 and peeling in the wafer peeling step.

[0019] (3) Wafer planarization process: Of the wafer front surface 11 and wafer back surface 12, which are the main surfaces of the wafer 1, at least the wafer back surface 12, which has unevenness caused by the peeling layer 23 and peeling in the wafer peeling process, is planarized to obtain a final wafer 1 having an epi-ready main surface. In the wafer planarization process, in addition to general grinding stone polishing and CMP, ECMG and ECMP can be used. Note that 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 planarization process can be performed by using one of these selectable types of planarization processes alone, or by appropriately combining multiple types.

[0020] (4) Ingot flattening process: The ingot top surface 21 newly generated after peeling off the wafer precursor 24 has rough unevenness (i.e., to the extent that grinding or polishing is required) due to the peeling layer 23 and peeling off by the wafer peeling process. Therefore, such ingot top surface 21 is flattened, i.e., mirror-finished, so that the ingot 2 that has been subjected to the wafer peeling process can be reused in the peeling layer forming process. In the ingot flattening process, in addition to general grindstone polishing and CMP, ECMG and ECMP can be used. The ingot flattening process can also be performed by using one of these selectable types of flattening processes alone or by appropriately combining multiple types.

[0021] (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 a laser beam B having transparency to an ingot top surface 21, which is an end surface on one side in the height direction of the ingot 2, in order to obtain a wafer 1 from the ingot 2. Specifically, as shown in FIG. 2, the laser processing apparatus 30 includes a chuck 31, a chuck moving mechanism 32, a support table 33, a transmitter 34, a laser irradiation device 35, a measuring device 36, and a control unit 37. Each part constituting the laser processing apparatus 30 will be described below in order. Note that the right-handed XYZ coordinates shown in each of the figures from FIG. 2 onwards are displayed so as to match the right-handed XYZ coordinates shown in FIG. 1. In addition, in this embodiment, the positive direction of the Z axis is assumed to point vertically upward. That is, the negative direction of the Z axis is assumed to be the same direction as or approximately the same direction as the direction of gravity. For the sake of simplicity of illustration and convenience of explanation, in FIG. 2, only the location of the measuring device 36 in the Y-axis direction is shown by a two-dot chain rectangle, and the specific configuration is shown in FIGS.

[0022] (Chuck) The chuck 31 is provided to support the ingot 2 with the ingot top surface 21 exposed upward by bonding with the ingot bottom surface 22, which is the other end surface in the height direction of the ingot 2. Specifically, the chuck 31 has a chuck surface 311 exposed upward when the ingot 2 is not supported. The chuck surface 311 bonded with the ingot bottom surface 22 has good flatness and is provided so as to be approximately parallel to the XY plane. The chuck 31 is adapted to fixedly support the ingot 2 on the chuck surface 311 by a well-known method (i.e., for example, suction or adhesion by negative pressure). The chuck 31 is fixedly supported on the upper surface of a chuck table 320 provided in the chuck moving mechanism 32.

[0023] (Chuck movement mechanism) The chuck moving mechanism 32 is configured to be movable in an in-plane direction while fixedly supporting the chuck 31. 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 on a main surface exposed upward by screwing or the like. The first slide mechanism 321 is configured to be capable of reciprocating the chuck table 320 in the in-plane direction, i.e., the X-axis direction. The second slide mechanism 322 is configured to be capable of reciprocating the chuck table 320 in the in-plane direction, i.e., 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 that are extended in the Y-axis direction and placed on the support base 33, and a Y-axis slider 322b that is slidably provided on the Y-axis slide rails 322a. The first slide mechanism 321 is fixedly supported on the Y-axis slider 322b. The first slide motor 323 is provided so as to be able to drive 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 be able to drive a ball screw (not shown) in the second slide mechanism 322 to reciprocate the chuck table 320 together with the first slide mechanism 321 in the Y-axis direction.

[0024] (Support stand) The support table 33 forming the basic structure of the laser processing device 30 has a surface plate portion 331 and a base portion 332. For example, a stone surface plate that is less affected by deformation or dimensional change due to temperature change and has excellent physical and mechanical strength can be used as the surface plate portion 331. Such a stone surface plate can be made of, for example, granite (i.e., mica stone). The surface plate portion 331 is formed in a thick plate shape, and the levelness of the upper and lower plate surfaces is precisely finished. The surface plate portion 331 is supported from below by the base portion 332 having a vibration control function. A chuck movement mechanism 32, a laser irradiation device 35, and a measurement device 36 are provided on the surface plate portion 331.

[0025] (Laser irradiation device) The laser irradiation device 35 is disposed on one side (i.e., the Y-axis positive side in the configuration example shown in FIG. 2) of the range in which the chuck table 320 can be moved in the Y-axis direction by the second slide mechanism 322. The laser irradiation device 35 is configured to irradiate the laser beam B output from an oscillator 34, which is a source of the laser beam B, downward in the figure toward the ingot 2 held by the chuck 31. 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 moving mechanism 357.

[0026] The optical system 351 is provided in the laser light path BL between the transmitter 34 and the condenser 356. The optical system 351 includes various optical elements such as lenses and reflectors, a beam expander that expands the beam diameter of the laser beam B, and a spatial light modulator that modulates the laser beam B. The optical system 351 is installed on the upper main surface of an optical system stage 352 formed in a plate shape having a plate thickness direction in the Z-axis direction from a material such as a metal having rigidity. 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, penetrate. The optical system guide body 353 is provided so that its lower end is supported on the support base 33 and its upper end 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 located on the corners or sides of a rectangle in a plan view seen from above with a line of sight parallel to the Z-axis direction. The optical system stage 352 is provided so as to be movable up and down along the Z-axis direction while being guided by a plurality of optical system guide bodies 353. The stage movement mechanism 354 serving as a coarse movement mechanism is a ball screw mechanism including a coarse movement motor 354a, and is configured to move the optical system stage 352 up and down along the Z-axis direction, i.e., the height direction of the ingot 2. The stage position scale 355 is configured as a linear scale for detecting the position of the optical system stage 352 in the Z-axis direction.

[0027] The condenser 356 includes an optical element such as an objective lens, and is configured to form a focal point BP of the laser beam B at a predetermined position below. That is, the condenser 356 is arranged to face the ingot top surface 21 along the height direction of the ingot 2 so that when the chuck table 320 reaches a predetermined processing area with the chuck 31 supporting the ingot 2, the condenser 356 irradiates the ingot top surface 21 with the laser beam B to concentrate the laser beam B inside the ingot 2.

[0028] The condenser 356 is supported by the optical system stage 352 via the condenser moving mechanism 357. That is, the condenser 356 is fixed to the bottom surface of the condenser moving mechanism 357. The condenser moving mechanism 357 is fixed to the optical system stage 352. The condenser moving mechanism 357 is a linear stage that expands and contracts in the Z-axis direction, and has a configuration as a piezo stage driven by a piezoelectric element, for example. In this way, the condenser moving mechanism 357 as a fine movement mechanism is fixed to the optical system stage 352, and is provided to support the condenser 356 so that the condenser 356 can be moved up and down together with the optical system stage 352 by the stage moving mechanism 354 as a coarse movement mechanism, while supporting the condenser 356 so that the condenser 356 can be moved up and down relatively to the optical system stage 352 along the height direction of the ingot 2.

[0029] (Measuring Equipment) 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 disposed on the other side (i.e., the Y-axis negative side in the configuration example shown in FIG. 2) of the range in which the chuck table 320 can be moved along the Y-axis direction by the second slide mechanism 322. That is, the laser irradiation device 35 and the measuring device 36 are provided adjacent to each other along the Y-axis direction. The laser processing device 30 is configured to irradiate the ingot top surface 21 with a laser beam B having transparency by the laser irradiation device 35 based on the ingot height measured by the measuring device 36 in order to obtain a wafer 1 from the ingot 2.

[0030] A specific configuration of the measuring device 36 will be described below with reference to Fig. 2 as well as Fig. 3 and Fig. 4. The measuring device 36 is supported by a support frame 360 ​​that is fixedly supported by the support base 33 shown in Fig. 2. The measuring device 36 includes a contact 361, a contact holder 362, a contact movable stage 363, a position detection unit 364, a lifting member 365, and a lifting unit lifting mechanism 366.

[0031] The contactor 361 faces the ingot top surface 21 along the Z axis direction, i.e., the height direction of the ingot 2, and extends along the Z axis direction toward the ingot top surface 21 so as to be able to abut against the ingot top surface 21. Specifically, the contactor 361 has a tip portion 361a which is one end in the extension direction, i.e., the Z axis direction, and abuts against the ingot top surface 21, and a base portion 361b on the opposite side. The contactor 361 is fixedly supported by a contactor holder 362 at the base portion 361b.

[0032] The contact holder 362 has a contact support portion 362a that fixedly supports the base end portion 361b of the contact 361, and a fixed portion 362b that is provided along the Z axis to support the contact support portion 362a in a cantilever shape. The contact holder 362 is formed in a substantially L-shape in a side view so that the flat contact support portion 362a having a thickness direction in the Z axis direction is extended from the flat fixed portion 362b having a thickness direction in the Y axis direction toward the negative direction of the Y axis. In this embodiment, the contact 361 is fixed to the contact support portion 362a by any fixing means such as screwing, bonding, or welding. The fixed portion 362b is attached to the contact movable stage 363 so as to be reciprocally movable along the Z axis direction. That is, the contact movable stage 363 as a contact guide portion is provided so as to guide the contact 361 slidably along the Z axis direction together with the contact support portion 362a. The contactor 361 and the contactor holder 362 are biased toward the ingot top surface 21 by their own weight and are guided by the contactor movable stage 363 so as to be slidable along the Z-axis direction. The position detector 364 is provided so as to generate an output corresponding to the position of the contactor 361 or the contactor support part 362a in the Z-axis direction. Specifically, the position detector 364 has a configuration as a linear scale attached to the fixed part 362b.

[0033] The lifting member 365 has a base plate-shaped portion 365a and a contactor holding portion 365b. The base plate-shaped portion 365a is formed in a flat plate shape having a plate thickness direction in the Y-axis direction, and is supported by the lifting portion lifting mechanism 366 so as to be slidable along the Z-axis direction. The contactor holding portion 365b is disposed below the contactor support portion 362a so as to be able to abut against the contactor support portion 362a. The contactor holding 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 toward the negative direction of the Y-axis. As shown in FIG. 3, the contactor holding portion 365b is configured to be separated from the contactor support portion 362a below the contactor support portion 362a in a measurement state in which the tip portion 361a of the contactor 361 abuts against the ingot top surface 21. On the other hand, as shown in FIG. 4, in a non-measurement state in which the tip 361a of the contactor 361 is spaced above the ingot top surface 21, the contactor holding portion 365b abuts against the contactor support portion 362a to support the contactor support portion 362a from below.

[0034] In this embodiment, the contact holding portion 365b has a side protrusion 365c and an abutment protrusion 365d. The side protrusion 365c is a flat plate-like portion having a plate thickness direction in the Z-axis direction, and its end on the Y-axis positive side is connected to the lower end of the base plate portion 365a. The abutment protrusion 365d protrudes upward from the side protrusion 365c. The abutment protrusion 365d is disposed directly below a portion of the contact support portion 362a in the in-plane direction where the contact 361 is not provided, so that the abutment protrusion 365d abuts against the contact support portion 362a from below when the lift member 365 moves upward from the lowered position shown in FIG. 3 as shown in FIG. 4.

[0035] The lifting section lifting mechanism 366 has a configuration as a so-called ball screw driven uniaxial stage capable of reciprocating the lifting member 365 in the Z-axis direction. That is, the lifting section lifting mechanism 366 includes a lifting section slide mechanism 367 and a lifting section drive device 368. The lifting section slide mechanism 367 is a uniaxial slide stage having a slide rail and a slider, and a base plate-like part 365a of the lifting member 365 is fixed to the slider part. The lifting section drive device 368 is a motor that drives a ball screw provided in the lifting section lifting mechanism 366, and is provided to move the lifting member 365, i.e., the contactor lifting part 365b, up and down along the Z-axis direction.

[0036] The buffer portion 369 is provided to absorb the impact when the contact support portion 362a descends and the tip portion 361a of the contact 361 abuts against the ingot top surface 21. Specifically, in this embodiment, the buffer portion 369 has a configuration as a counterbalance cylinder that expands and contracts along the Z-axis direction.

[0037] (Control unit) 2 again, the control unit 37 is provided to control the overall operation of the laser processing apparatus 30. In this embodiment, the control unit 37 has a configuration as a so-called microcomputer equipped with a processor and a memory, and controls the operation of each part in the laser processing apparatus 30 by reading and starting a program prestored in the memory by the processor. The "memory" is a non-transient tangible storage medium such as a ROM, a magnetic disk, an optical disk, a flash memory, etc. At least one processor and one memory are provided.

[0038] Specifically, the control unit 37 controls the operation 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, i.e., the ingot 2, in the XY plane to a desired position. The control unit 37 also controls the generation and stopping of the laser beam B in the transmitter 34. The control unit 37 also controls the operation of each part in the optical system 351 to adjust the beam shape of the laser beam B and the laser optical path BL, etc. The control unit 37 also controls the operation of the stage moving mechanism 354, which is a coarse movement mechanism, to adjust the position of the optical system stage 352, i.e., the optical system 351, in the Z-axis direction. The control unit 37 also controls the operation of the condenser moving mechanism 357, which is a fine movement mechanism, to adjust the relative position of the condenser 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 moving mechanism 357 in accordance with the positioning error of the stage moving mechanism 354 to adjust the height of the condenser 356, i.e., the position in the Z-axis direction. The control unit 37 also controls the operation of the measuring device 36 to measure the ingot height at multiple points in the in-plane direction of the ingot top surface 21, and based on the ingot height measured by the measuring device 36, controls the operation of the collector moving mechanism 357 for each irradiation of the laser beam B. The control unit 37 also controls the operation of the collector moving mechanism 357 for each irradiation of the laser beam B (i.e., for each of the multiple irradiation positions PR on the ingot top surface 21) based on the chuck surface height, which is the height of the chuck surface 311 measured in advance.

[0039] (operation) Hereinafter, an overview of the operation of the laser processing apparatus 30 having the above-mentioned configuration will be described together with the effects achieved by this configuration with reference to the various drawings.

[0040] 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. 2. In the measurement area, the ingot 2 fixed to the chuck 31 is positioned directly below the measuring device 36. Then, in this measurement area, the control unit 37 measures the ingot height at multiple points in the in-plane direction of the ingot top surface 21 using the measuring device 36, while controlling the operation of the first slide motor 323 and the second slide motor 324 in the chuck moving mechanism 32.

[0041] When starting to measure the ingot height, the measuring device 36 is initially in an initial state as a non-measurement state as shown in FIG. 4. In the initial state, the lifting member 365 is elevated to such an extent that the tip 361a of the contactor 361 is above the ingot top surface 21 and is separated from the ingot top surface 21, resulting in a non-measurement state. The initial state refers to a state in which the lifting member 365 is elevated until a sufficient gap is formed such that the tip 361a of the contactor 361 does not come into contact with the ingot top surface 21 even when the chuck table 320 is driven in the X-axis or Y-axis direction to move the ingot 2. In this initial state, the contactor 361 and the contactor holder 362 are urged downward toward the ingot top surface 21 by their own weight, so that the contactor support portion 362a comes into contact with the contactor holding portion 365b, i.e., the contact protrusion 365d. That is, in a non-measurement state in which tip end 361a of contactor 361 is above ingot top surface 21 and separated from ingot top surface 21, contactor holding portion 365b abuts against contactor support portion 362a, thereby supporting contactor support portion 362a from below. When lifting member 365 begins to move down from such an initial position by operation of lifting portion lifting mechanism 366, contactor 361 and contact holder 362 move down together with lifting member 365 while being supported from below by contactor holding portion 365b until tip end 361a of contactor 361 abuts against ingot top surface 21.

[0042] The tip 361a of the contactor 361 descending together with the contactor support portion 362a comes into contact with the ingot top surface 21, thereby forming the measurement state. The impact of the contact at this time is well mitigated by the buffer portion 369. 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 any further. Therefore, after the tip 361a of the contactor 361 comes into contact with the ingot top surface 21 to form the measurement state, the contactor holder 365b is separated from the contactor support portion 362a below the contactor support portion 362a, as shown in FIG. 3. That is, the contactor 361 and the contactor holder 362 are "left behind" by the descent of the lifting member 365.

[0043] As shown in Fig. 4, in the non-measurement state, i.e., in the state where the contactor holding part 365b supports the contactor support part 362a while contacting it from below, the output of the position detector 364 changes continuously as the lifting member 365 descends at a constant speed. On the other hand, when the tip 361a of the contactor 361 abuts against the ingot top surface 21 to form the measurement state, the continuous change in the output of the position detector 364 as described above ends. However, at the moment of abutment or immediately thereafter, a buffering effect is generated by the buffer part 369, which is a counterbalance means. Therefore, the control part 37 measures the ingot height at a certain point in the in-plane direction based on the output of the position detector 364, not at the moment or immediately thereafter when the tip 361a of the contactor 361 abuts against the ingot top surface 21, but at the time when the contactor holding part 365b is separated from the contactor support part 362a by a predetermined amount.

[0044] When the control unit 37 has thus measured the ingot height at one point in the in-plane direction, it drives the lifting unit lifting mechanism 366 to lift the lifting member 365. When the lifting member 365 rises until the contactor holding unit 365b, i.e., the abutting protrusion 365d, comes into contact with the contactor support unit 362a, the contactor 361 rises together with the contactor holder 362 as the lifting member 365 rises. That is, the contactor 361 and the contactor holder 362 are "suspended" by the lifting member 365 that is rising. Then, when the lifting member 365 and the contactor 361 rise to the initial state described above, the chuck table 320 is driven by a predetermined amount in the X-axis and / or Y-axis directions, so that the contactor 361 faces the next measurement point in the in-plane direction of the ingot top surface 21.

[0045] Thus, according to the configuration of this embodiment, the ingot height is measured relatively quickly and accurately while suppressing damage to the ingot 2 (i.e., for example, the occurrence of scratches on the ingot top surface 21). That is, it is possible to measure the ingot height more accurately than with optical methods or ultrasonic distance measuring methods. Also, damage to the ingot 2 during measurement can be effectively suppressed without slowing down the descending speed of the contactor 361. Therefore, according to this embodiment, it is possible to improve productivity compared to the conventional wafer manufacturing technology in which a wafer 1 is obtained from an ingot 2 by so-called laser slicing.

[0046] When the measurement of the ingot height 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 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 processing area. In the processing area, the ingot 2 fixed to the chuck 31 is located directly below the condenser 356. Then, the control unit 37 irradiates the ingot top surface 21 with the laser beam B while controlling the depth of the condensation point BP from the ingot top surface 21 based on the measurement result of the ingot height, thereby forming the peeling layer 23. FIG. 1 shows the irradiation and scanning of the laser beam B on the ingot 2. In addition, since the illustration shows the relative movement of the condenser 356 and the irradiation position PR with respect to the ingot 2, the condenser 356 and the irradiation position PR appear to move in the XY direction. However, in reality, in the laser processing device 30, the condenser 356, i.e., the irradiation position PR, is fixed in the XY direction, while the ingot 2 is moved in the XY direction by the chuck movement mechanism 32. As shown in FIG. 1, forward scanning Sc1 in which the condenser 356 moves relative to the ingot 2 in a first direction parallel to the X axis, and backward scanning Sc2 in which the condenser 356 moves relative to the ingot 2 in a second direction parallel to the X axis and opposite to the first direction, are alternately repeated. Between the forward scanning Sc1 and the backward scanning Sc2, index feeding is performed in which the chuck table 320 is fed a predetermined small amount in the Y axis direction. The irradiation of the laser beam B is performed intermittently within the region of the ingot top surface 21, at least between the forward scanning Sc1 and the backward scanning Sc2. That is, during the forward scan Sc1 and / or the backward scan Sc2, irradiation with the laser beam B is performed multiple times. Note that scanning with the laser beam B during one forward scan Sc1 or one backward scan Sc2 is hereinafter referred to as "laser scanning".

[0047] Here, when attempting to increase the processing speed (for example, 500 mm / s, 0.5 G acceleration / deceleration, etc.), vibration in the height direction becomes a problem. In this regard, if a vertical setup (i.e., position adjustment in the Z-axis direction) mechanism is provided on the chuck table 320 side, there is a risk that such vibration will be promoted. Therefore, in this embodiment, the vertical 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 condenser 356 side. In such a vertical setup mechanism, a vertical setup stroke of about 50 mm is usually required. In addition, in recent years, the inertia of the vertical setup mechanism has increased due to an increase in the size of the optical system 351. For this reason, in the conventional technology, due to the large stroke and large inertia of the vertical setup mechanism, it was difficult to precisely control the depth of the focal point BP from the ingot top surface 21 (for example, at the submicron level) or to control the focal position in real time. This increases the processing allowance for polishing and grinding in the wafer flattening process, leading to a deterioration in the material yield in wafer manufacturing. In particular, the method described in Patent Document 1, which uses the measurement value of only one point at the center of the in-plane direction of the ingot 2, or the average value of detection values ​​at multiple points, was unable to counteract the effects of the parallelism of the ingot 2 and the straightness of the stage.

[0048] Therefore, in the configuration according to this embodiment, rough up-down setup is performed by the stage moving mechanism 354, which is a coarse movement mechanism with a large stroke and high inertia, and precise up-down setup is performed by the condenser moving mechanism 357, which is a fine movement mechanism with a small stroke and low inertia. Here, by using, for example, a so-called piezo stage as the condenser moving mechanism 357, it is possible to perform up-down setup at a high speed with a resolution of 10 nm level. In addition, by reflecting the measured values ​​at each point, rather than the average value, of the ingot height measured at multiple points in the in-plane direction of the ingot top surface 21 in the precise and high-speed up-down setup by the condenser moving mechanism 357, it is possible to precisely control the depth of the focusing point BP from the ingot top surface 21 in real time for each irradiation of the laser beam B. This can satisfactorily reduce the processing cost of polishing and grinding in the wafer flattening process. Therefore, according to this embodiment, it is possible to improve productivity more than ever before in the wafer manufacturing technology in which a wafer 1 is obtained from an ingot 2 by so-called laser slicing.

[0049] As described above, since the position of the condenser 356 is fixed in the XY direction, the chuck moving mechanism 32 for moving the ingot 2 relative to the condenser 356 in the XY direction requires a stroke at least equal to or greater than the outer diameter of the ingot 2. The same applies to the measuring device 36. For this reason, in practice, a stroke at least twice the outer diameter of the ingot 2 or more is required. Thus, the straightness error in the chuck moving mechanism 32 becomes a problem. That is, if the peeling layer 23 is tilted or an error occurs in the depth of the condensing point BP from the ingot top surface 21 due to the influence of the straightness error in the chuck moving mechanism 32, the processing cost of polishing and grinding in the wafer flattening process increases, leading to a deterioration in the material yield in the wafer manufacturing. The 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 the dimensional error of the chuck 31 during manufacturing.

[0050] Therefore, in the configuration according to the present 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 reflected in the Z-axis position control of the condenser 356 by the condenser moving mechanism 357. That is, the control unit 37 controls the condenser moving mechanism 357 for each irradiation of the laser beam B based on the chuck surface height measured in advance. This effectively reduces the processing cost of polishing and grinding in the wafer flattening process, thereby further improving productivity compared to the conventional technique. The chuck surface height can be measured, for example, by a height measuring device (not shown) fixed to the condenser moving mechanism 357 together with the condenser 356. Alternatively, the chuck surface height can be measured using the measuring device 36, for example, if the distance in the Y-axis direction between the measurement area and the processing area is sufficiently small so that the influence of the straightness of the Y-axis slide rail 322a can be ignored to a certain extent.

[0051] Although the target value of the stage moving mechanism 354, which is a coarse movement mechanism, is determined based on the precise measurement result, the deviation is not necessarily made completely zero by the positioning command. Therefore, in the configuration according to this embodiment, the control unit 37 controls the condenser moving mechanism 357 according to the positioning error of the stage moving mechanism 354. That is, the control unit 37 applies correction to the condenser moving mechanism 357, which is a fine movement mechanism, for the positioning error of the stage moving mechanism 354, which is a coarse movement mechanism. Specifically, for example, the control unit 37 controls the driving of the coarse movement motor 354a, which is a servo motor, while referring to the output of the stage position scale 355. Then, the control unit 37 returns the error of the accumulated pulse to the condenser moving mechanism 357 as a correction value. This makes it possible to precisely control the depth of the focal point BP from the top surface 21 of the ingot, and further improves productivity compared to the conventional method.

[0052] (Modification) The present invention is not limited to the above embodiment. Therefore, the above embodiment can be modified as appropriate. Representative modified examples will be described below. In the following description of the modified examples, differences from the above embodiment will be mainly described. In addition, the same reference numerals are used for parts that are the same or equivalent to each other in the above embodiment and the modified examples. Therefore, in the following description of the modified examples, the description of the above embodiment can be appropriately used for components having the same reference numerals as the above embodiment, unless there is a technical contradiction or special additional explanation.

[0053] The present invention is not limited to the specific configurations shown in the above embodiments. For example, the positive direction of the Z axis does not have to be vertically upward. In other words, the positive direction of the Z axis may be a direction that intersects with the vertically upward direction, which is the opposite direction to the direction of gravity.

[0054] The first slide mechanism 321 may be configured to be capable of moving the chuck table 320 in the X and Y directions. That is, unlike the second slide mechanism 322 which is 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 321 which has a relatively short movable range approximately equal to the outer diameter of the ingot 2 may be given a function as a fine movement mechanism in the Y-axis direction. This allows the feed amount of the chuck table 320, i.e., the ingot 2, in the Y-axis direction to be controlled more precisely during measurement by the measuring device 36 and during processing by the laser irradiation device 35.

[0055] There is no particular limitation on the type of the various motors such as the first slide motor 323, the second slide motor 324, the coarse movement motor 354a, etc. That is, for example, a linear motor may be used.

[0056] The contacts 361 may be seamlessly formed integrally with the contact support portion 362a using the same material, that is, the contacts 361 may be protrusions formed on the contact support portion 362a.

[0057] The contact protrusion 365d may be seamlessly formed integrally with the side protrusion 365c using the same material. That is, the contact protrusion 365d may be a protrusion formed on the side protrusion 365c. Alternatively, the contact protrusion 365d may be omitted. That is, the contact holding portion 365b may be composed only of the side protrusion 365c.

[0058] The lifting section lifting mechanism 366 is not limited to a ball screw structure, but may be a fluid pressure cylinder or the like.

[0059] The buffer portion 369 is not limited to a counterbalance cylinder, and may be configured using, for example, a spring or elastomer rubber (such as silicone rubber).

[0060] Due to thermal expansion caused by a temperature rise during laser processing, the depth of the focal point BP from the top surface 21 of the ingot may vary. Therefore, as shown in FIG. 5 and FIG. 6, a reference block 381 is provided on the chuck 31 side, 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 measured at any time by a length measuring sensor 382, ​​thereby realizing a correction function for the thermal expansion. The reference block 381 may be formed, for example, from a material with a small thermal expansion coefficient (for example, a 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. The length measuring sensor 382 has a well-known contact type or non-contact type configuration so as to measure the reference block height, which is the height of the reference block 381, i.e., the reference surface 381a, and is fixed to the condenser moving mechanism 357 together with the condenser 356.

[0061] In this 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 control unit 37 controls the condenser moving mechanism 357 in a timely manner according to the measured reference block height. Specifically, for example, the control unit 37 moves the chuck table 320 to a length measurement position where the reference surface 381a is located directly below the length measurement sensor 382 as shown in FIG. 6 before starting laser processing after the chuck table 320 moves from the measurement area to the processing area, and measures the reference block height. Then, after performing laser processing a predetermined number of times or for a predetermined time, the control unit 37 moves the chuck table 320 to the length measurement position and remeasures the reference block height, and reflects the change from the reference value measured before processing as the amount of thermal elongation in the correction of the condenser moving mechanism 357. The remeasurement can be performed after a predetermined number of laser scans or at a predetermined time interval.

[0062] By configuring the laser processing apparatus 30 so that the laser beam B can be irradiated to different positions in the in-plane direction of the ingot top surface 21 during one laser scan, the cycle time is effectively shortened and the productivity is further improved. Therefore, the laser processing apparatus 30 may be configured to include a plurality of optical systems 351 and to irradiate the laser beam B that has passed through each of the plurality of optical systems 351 to different positions in the in-plane direction of the ingot top surface 21. Specifically, for example, the laser beam B emitted from a common oscillator 34 may be split into two by a beam splitter, and each of the laser beams may pass through each of the two optical systems 351 and be irradiated to the ingot top surface 21 from each of the two collectors 356. In this case, the collectors 356 may be provided in the same number as the optical systems 351 as described above, or the plurality of optical systems 351 may be configured to introduce the laser beam B into the same, i.e., common, collector 356. Alternatively, for example, as described in JP 2016-225536 A, the laser beam B may be split into a plurality of beams by a diffractive optical element provided inside the condenser 356.

[0063] In the above description, a plurality of components that were formed seamlessly and integrally with each other may be formed by bonding separate members together. Similarly, a plurality of components that were formed by bonding separate members together may be formed seamlessly and integrally with each other. Furthermore, in the above description, a plurality of components that were formed from the same material may be formed from different materials together. Similarly, a plurality of components that were formed from different materials together may be formed from the same material together.

[0064] Needless to say, the elements constituting the above-mentioned embodiment are not necessarily essential, except when expressly stated as essential or when considered to be obviously essential in principle. Furthermore, when the numbers, amounts, ranges, etc. of the components are mentioned, the present invention is not limited to the specific values, except when expressly stated as essential or when clearly limited to a specific value in principle. Similarly, when the shapes, directions, positional relationships, etc. of the components are mentioned, the present invention is not limited to the shapes, directions, positional relationships, etc., except when expressly stated as essential or when clearly limited to a specific shape, direction, positional relationship, etc. in principle.

[0065] The modified examples are not limited to the above examples. In addition, multiple modified examples may be combined with each other unless technically inconsistent. [Explanation of symbols]

[0066] 2 Ingots 36 Measuring Equipment 361 Contact 361a Tip 361b Proximal end 362a Contact support part 363 Contactor movable stage (contactor guide) 364 Position detector 365b Contact holder 368 Lifting unit drive unit

Claims

1. 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), A contact (361) is provided extending along the height direction toward a top surface (21), which is an end surface on one side in the height direction of the ingot, in a state facing the top surface along the height direction so as to be able to abut against the top surface; a contact support portion (362a) that fixedly supports the contact at a base end portion (361b) opposite to a tip end portion (361a) that abuts against the top surface, the base end portion being one end portion of the contact in the height direction; A contact guide portion (363) that guides the contact support portion slidably along the height direction; a position detection unit (364) that generates an output corresponding to a position in the height direction of the contact or the contact support unit; a contact holder (365b) disposed below the contact support portion so as to be capable of coming into contact with the contact support portion; A lifting part driving device (368) that moves the contact holding part up and down along the height direction; a buffer portion (369) provided to absorb an impact when the tip portion of the contact abuts against the top surface due to the lowering of the contact support portion; Equipped with The buffer unit includes a counterbalance cylinder that expands and contracts along the height direction. Measuring equipment.

2. the contact and the contact support are slidably provided along the height direction while being biased toward the top surface by their own weights, The contact holding portion is In a non-measurement state in which the tip of the contact is above the top surface and separated from the top surface, the tip of the contact abuts against the contact support portion to support the contact support portion from below; the contact support portion is provided below the contact support portion and spaced apart from the contact support portion in a measurement state in which the tip portion of the contact contact is in contact with the top surface, 2. The measuring device of claim 1.

3. A laser processing device (30) comprising a measuring device (36) for measuring an ingot height, which is the height of an ingot (2) to be processed by the laser processing device (30), and configured to irradiate a laser beam having transparency to a top surface (21), which is an end surface on one side in the height direction of the ingot, based on the ingot height measured by the measuring device, in order to obtain a wafer (1) from the ingot, a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by joining with a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path (BL) between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) for supporting the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; A control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with The measuring device is A contact (361) extending along the height direction toward the top surface in a state facing the top surface along the height direction and capable of abutting against the top surface; a contact support portion (362a) that fixedly supports the contact at a base end portion (361b) opposite to a tip end portion (361a) that abuts against the top surface, the base end portion being one end portion of the contact in the height direction; A contact guide portion (363) that guides the contact support portion slidably along the height direction; a position detection unit (364) that generates an output corresponding to a position in the height direction of the contact or the contact support unit; a contact holder (365b) disposed below the contact support portion so as to be capable of coming into contact with the contact support portion; A lifting part driving device (368) that moves the contact holding part up and down along the height direction; Equipped with the control unit controls the fine movement mechanism in accordance with a positioning error of the coarse movement mechanism. Laser processing equipment.

4. A reference block (381) fixedly supported by the chuck table; a length measuring sensor (382) fixed to the fine movement mechanism so as to measure a reference block height, which is the height of the reference block; Further equipped with The length measuring sensor measures the height of the reference block a plurality of times during a series of laser processing steps for obtaining one of the wafers, The control unit controls the fine movement mechanism in accordance with the measured reference block height. The laser processing apparatus according to claim 3.

5. A laser processing device (30) comprising a measuring device (36) for measuring an ingot height, which is the height of an ingot (2) to be processed by the laser processing device (30), and configured to irradiate a laser beam having transparency to a top surface (21), which is an end surface on one side in the height direction of the ingot, based on the ingot height measured by the measuring device, in order to obtain a wafer (1) from the ingot, a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by joining with a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path (BL) between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) for supporting the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; A reference block (381) fixedly supported by the chuck table; a length measuring sensor (382) fixed to the fine movement mechanism so as to measure a reference block height, which is the height of the reference block; A control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with The measuring device is A contact (361) extending along the height direction toward the top surface in a state facing the top surface along the height direction and capable of abutting against the top surface; a contact support portion (362a) that fixedly supports the contact at a base end portion (361b) opposite to a tip end portion (361a) that abuts against the top surface, the base end portion being one end portion of the contact in the height direction; A contact guide portion (363) that guides the contact support portion slidably along the height direction; a position detection unit (364) that generates an output corresponding to a position in the height direction of the contact or the contact support unit; a contact holder (365b) disposed below the contact support portion so as to be capable of coming into contact with the contact support portion; A lifting part driving device (368) that moves the contact holding part up and down along the height direction; Equipped with The length measuring sensor measures the height of the reference block a plurality of times during a series of laser processing steps for obtaining one of the wafers, The control unit controls the fine movement mechanism in accordance with the measured reference block height. Laser processing equipment.

6. 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 ingot height measured by the measuring device.

6. The laser processing apparatus according to claim 4 or 5.

7. The contact and the contact support are slidably provided along the height direction while being biased toward the top surface by their own weight, The contact holding portion is In a non-measurement state in which the tip of the contact is above the top surface and separated from the top surface, the tip of the contact abuts against the contact support portion to support the contact support portion from below; the contact support portion is provided below the contact support portion and spaced apart from the contact support portion in a measurement state in which the tip portion of the contact contact is in contact with the top surface, The laser processing device according to any one of claims 3 to 6.

8. The contact support further includes a buffer portion (369) provided to absorb an impact when the tip of the contact contacts the top surface due to the descent of the contact support portion. The laser processing device according to any one of claims 3 to 7.

9. The buffer section is provided with a counterbalance cylinder that expands and contracts along the height direction, The laser processing apparatus according to claim 8.

10. A laser processing apparatus (30) for irradiating a top surface (21), which is an end surface on one side in a height direction of an ingot (2), with a laser beam having transparency in order to obtain a wafer (1) from the ingot, comprising: a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by joining with a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path (BL) between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) for supporting the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; A control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with the control unit controls the fine movement mechanism in accordance with a positioning error of the coarse movement mechanism. Laser processing equipment.

11. A reference block (381) fixedly supported by the chuck table; a length measuring sensor (382) fixed to the fine movement mechanism so as to measure a reference block height, which is the height of the reference block; Further equipped with The length measuring sensor measures the height of the reference block a plurality of times during a series of laser processing steps for obtaining one of the wafers, The control unit controls the fine movement mechanism in accordance with the measured reference block height. The laser processing apparatus according to claim 10.

12. A laser processing apparatus (30) for irradiating a laser beam having transparency onto a top surface (21), which is an end surface on one side in a height direction of an ingot (2), in order to obtain a wafer (1) from the ingot, comprising: a collector (356) disposed opposite the top surface along the height direction so that the laser beam is irradiated onto the top surface to collect the laser beam inside the ingot; a chuck (31) provided to support the ingot by joining with a bottom surface (22) which is the other end surface of the ingot in the height direction; a chuck moving mechanism (32) that is provided so as to be able to move a chuck table (320) that fixedly supports the chuck in an in-plane direction that intersects with the height direction; an optical system (351) provided in a laser optical path (BL) between a transmitter (34) which is a source of the laser beam and the condenser; an optical system stage (352) for supporting the optical system; a coarse movement mechanism (354) for moving the optical system stage up and down along the height direction; a fine movement mechanism (357) that is fixed to the optical system stage and moves up and down together with the optical system stage by the coarse movement mechanism while supporting the condenser so that the condenser can be moved up and down relatively to the optical system stage along the height direction; A reference block (381) fixedly supported by the chuck table; a length measuring sensor (382) fixed to the fine movement mechanism so as to measure a reference block height, which is the height of the reference block; A control unit (37) that controls the operation of the coarse movement mechanism and the fine movement mechanism; Equipped with The length measuring sensor measures the height of the reference block a plurality of times during a series of laser processing steps for obtaining one of the wafers, The control unit controls the fine movement mechanism in accordance with the measured reference block height. Laser processing equipment.

13. The control unit controls the micromotion mechanism for each irradiation of the laser beam based on a chuck surface height, which is a height of a surface (311) of the chuck that is joined to the bottom surface and is measured in advance. The laser processing apparatus according to any one of claims 3 to 12.

14. A plurality of the optical systems are provided, The laser beam passing through each of the plurality of optical systems is configured to be irradiated at different positions on the top surface. The laser processing apparatus according to any one of claims 3 to 13.

Images