Grinding device, work-piece grinding method, and substrate manufacturing method

Abstract

To suppress productivity and through-put from deteriorating in manufacturing a semiconductor device utilizing a work-piece.SOLUTION: A grinding device, which grinds one surface side of a work-piece having an altered layer formed on the one surface thereof, comprises: a holding unit for holding a work-piece so that the one surface is exposed; a grinding unit for grinding the one surface of the work-piece held by the holding unit; a photographing unit for photographing an image of the one surface of the work-piece held by the holding unit; and a controller that determines whether or not grinding of the one surface of the work-piece should be finished while referring to information concerning the altered layer that is obtained based on a photographed image of the one surface of the work-piece that is executed in parallel with grinding of the one surface side of the work-piece or after interrupting the grinding.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a grinding apparatus for grinding a workpiece having a modified layer on one surface side thereof, a grinding method for the workpiece for grinding one surface side of the workpiece, and a method for manufacturing a substrate having a thickness less than a predetermined thickness from an ingot having a predetermined thickness.

Background Art

[0002] A chip of a semiconductor device is generally manufactured using a substrate made of a single crystal such as silicon (Si), silicon carbide (SiC), gallium nitride (GaN), lithium tantalate (LiTaO3:LT), or lithium niobate (LiNbO3:LN). This substrate is manufactured, for example, by being cut out from an ingot using a wire saw.

[0003] However, the cutting loss when cutting out a substrate from an ingot using a wire saw is around 300 μm, which is relatively large. In addition, irregularities are formed on the surface of the substrate cut out in this way, and the substrate is curved as a whole (the substrate warps). Therefore, when manufacturing a chip using this substrate, it is necessary to flatten the surface by performing lapping, etching, and / or polishing on the surface of the substrate.

[0004] In this case, the amount of the material finally used as the substrate is about 2 / 3 of the total amount of the ingot. That is, about 1 / 3 of the total amount of the ingot is discarded during the cutting out of the substrate from the ingot and the flattening of the surface of the substrate. Therefore, when manufacturing a substrate using a wire saw in this way, the productivity is low.

[0005] In view of this point, a method for manufacturing a substrate for manufacturing a substrate from an ingot using a laser beam having a wavelength that penetrates the material of the ingot has been proposed (see, for example, Patent Document 1). Specifically, in this method, first, the ingot and the condensing point are relatively moved in a state where the condensing point where the laser beam is condensed is positioned inside the ingot.

[0006] As a result, a layer in which the crystal structure of the ingot material is disrupted (altered layer) and cracks extending from the altered layer are formed inside the ingot. In this method, an external force is applied to the ingot so as to further extend these cracks. As a result, the ingot separates starting from the altered layer, and a substrate is manufactured.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] As described above, when a substrate is manufactured from an ingot, an altered layer remains on each one-side of the ingot and the substrate (hereinafter, both are also collectively referred to as "workpiece"). Therefore, after manufacturing the substrate from the ingot in this way, it is common to grind one side of the workpiece so as to remove and flatten the altered layer.

[0009] However, individual differences may occur in the thickness of the altered layer remaining on one side of the workpiece. Therefore, when grinding one side of the workpiece, the grinding is often performed excessively (for example, removing a thickness several times larger than the assumed thickness of the altered layer) so that the entire altered layer is surely removed. In this case, the productivity of the semiconductor device manufactured using the workpiece decreases, and its throughput also becomes low.

[0010] In view of this point, an object of the present invention is to suppress a decrease in productivity and throughput when manufacturing a semiconductor device using a workpiece.

Means for Solving the Problems

[0011] According to one aspect of the present invention, there is provided a grinding apparatus for grinding one surface side of a workpiece having a modified layer on one surface side thereof, the grinding apparatus including: a holding unit for holding the workpiece such that the one surface side is exposed; a grinding unit for grinding the one surface side of the workpiece held by the holding unit; an imaging unit for imaging the one surface side of the workpiece held by the holding unit; and a controller for determining whether to end the grinding of the one surface side of the workpiece with reference to information regarding the modified layer obtained based on imaging of the one surface side of the workpiece performed in parallel with or interrupting the grinding of the one surface side of the workpiece.

[0012] The grinding apparatus of the present invention further includes a processing chamber cover surrounding a processing chamber capable of accommodating the workpiece held by the holding unit, the grinding unit, and the imaging unit, and the processing chamber cover preferably includes a partition plate for partitioning the processing chamber into a grinding space where grinding of the one surface side of the workpiece is performed and an imaging space where imaging of the one surface side of the workpiece is performed. Further, the grinding apparatus of the present invention preferably further includes a grinding fluid supply unit for supplying grinding fluid to a region to be ground on the one surface side of the workpiece, and a fluid injection unit for injecting a fluid so as not to allow the grinding fluid to enter a region to be imaged on the one surface side of the workpiece.

[0013] Furthermore, the holding unit has a chuck table for holding the workpiece on a holding surface, a motor for rotating the chuck table about a straight line passing through the center of the holding surface as a rotation axis, and an encoder for detecting a rotation angle of the chuck table, and the controller preferably identifies an element linearly extending along a direction that changes according to the rotation angle in the workpiece imaged by the imaging unit as the modified layer. In addition, the controller preferably changes grinding conditions with reference to the information during grinding of the one surface side of the workpiece.

[0014] According to another aspect of the present invention, there is provided a method for grinding a workpiece having a modified layer on one side thereof, the method comprising: a holding step of holding the workpiece such that the one side is exposed; and a grinding step of grinding the one side of the workpiece after the holding step, wherein whether to end the grinding step is determined with reference to information regarding the modified layer obtained based on imaging of the one side of the workpiece performed in parallel with or interrupting the grinding of the one side of the workpiece.

[0015] According to still another aspect of the present invention, there is provided a method for manufacturing a substrate having a thickness less than a predetermined thickness from an ingot having the predetermined thickness, the method comprising: a modified layer forming step of forming a modified layer inside the ingot by relatively moving the ingot and a condensing point at which a laser beam having a wavelength that penetrates the material of the ingot is condensed while positioning the condensing point inside the ingot; a substrate manufacturing step of manufacturing the substrate having the modified layer remaining on one side thereof by separating the ingot starting from the modified layer after the modified layer forming step; and a grinding step of grinding the one side of the substrate after the substrate manufacturing step, wherein whether to end the grinding step is determined with reference to information regarding the modified layer obtained based on imaging of the one side of the substrate performed in parallel with or interrupting the grinding of the one side of the substrate.

Advantages of the Invention

[0016] In the present invention, it is determined whether to end the grinding of one side of the workpiece with reference to information regarding the modified layer obtained based on imaging of one side of the workpiece performed in parallel with or interrupting the grinding of one side of the workpiece. In this case, an appropriate thickness of one side of the workpiece can be removed without excess or deficiency.

[0017] Specifically, in this case, without excessively grinding one surface side of the workpiece, for example, when it is determined that all of the altered layer has been removed, the grinding of one surface side of the workpiece can be terminated. Therefore, in the present invention, it is possible to suppress a decrease in productivity of a semiconductor device manufactured using the workpiece and to suppress a decrease in its throughput.

Brief Description of the Drawings

[0018]

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Embodiments for Carrying Out the Invention

[0019] Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing an example of a grinding apparatus. The X-axis direction (front-rear direction) and the Y-axis direction (left-right direction) shown in FIG. 1 are directions orthogonal to each other on a horizontal plane. The Z-axis direction (vertical direction) is a direction orthogonal to each of the X-axis direction and the Y-axis direction (vertical direction).

[0020] The grinding apparatus 2 shown in FIG. 1 has a base 4 that supports each component. On the upper surface of this base 4, a rectangular parallelepiped-shaped depression 4a extending along the X-axis direction is formed. And inside the depression 4a, a holding unit 6 for holding the workpiece 11 is provided.

[0021] The workpiece 11 is, for example, a substrate manufactured by separating an ingot starting from a damaged layer, or an ingot remaining after the manufacture of this substrate. The manufacturing method of such a substrate will be described later. On one surface 11a side of this workpiece 11 (specifically, the surface side newly exposed by separating the ingot), a damaged layer remains.

[0022] And one surface 11a side of the workpiece 11 is rougher than the other surface 11b side due to the presence of the damaged layer. Further, on the side surface of the workpiece 11, an orientation flat 11c for indicating the crystal orientation of its material (for example, a single crystal such as Si, SiC, GaN, LT, or LN) is formed.

[0023] The holding unit 6 has a chuck table 8 for holding the workpiece 11 on the holding surface. And the chuck table 8 is movable between a position (loading / unloading position) where the workpiece 11 is loaded onto and unloaded from the holding surface, and a position (grinding position) where the workpiece 11 held on the holding surface is ground.

[0024] In addition, FIG. 1 shows the grinding device 2 with the chuck table 8 positioned at the loading / unloading position. The grinding position is a position spaced apart in the X-axis direction when viewed from the loading / unloading position, specifically, a position behind it.

[0025] FIG. 2 is a diagram schematically showing a longitudinal section or the like of the chuck table 8 positioned at the grinding position. In FIG. 2, components of the holding unit 6 other than the chuck table 8 are shown in blocks. Further, FIG. 3 is a diagram schematically showing the upper surface or the like of the chuck table 8 positioned at the grinding position.

[0026] The chuck table 8 has, for example, a disk-shaped frame body 10 made of ceramics or the like. This frame body 10 has a disk-shaped bottom wall 10a and a cylindrical side wall 10b standing upright from the outer peripheral portion of this bottom wall 10a. That is, on the upper surface side of the frame body 10, a disk-shaped recess defined by the bottom wall 10a and the side wall 10b is formed.

[0027] And a disk-shaped porous plate 12 made of porous ceramics or the like is fixed to this recess. The upper surface of the side wall 10b of the frame body 10 and the upper surface of the porous plate 12 have a shape corresponding to the side surface of a cone and function as a holding surface when holding the workpiece 11.

[0028] Also, a flow path 10c that opens at the bottom surface of the recess and penetrates the bottom wall 10a is formed in the bottom wall 10a. And this flow path 10c communicates with the suction source 16a via the valve 14a and also communicates with the fluid supply source 16b via the valve 14b.

[0029] The suction source 16a includes, for example, an ejector or the like. The fluid supply source 16b includes, for example, a tank for storing high-pressure gas, a filter for removing foreign matters mixed in the gas supplied from the tank, and a regulator for adjusting the pressure of the gas supplied from the tank.

[0030] The chuck table 8 is also connected to the motor 18 via, for example, a pulley (not shown) and a belt (not shown) wound around the pulley. When the motor 18 is operated, the chuck table 8 rotates clockwise (along the direction of arrow A1 shown in FIG. 3) in a plan view with a straight line passing through the center of the holding surface of the chuck table 8 as the rotation axis.

[0031] An encoder 20 is provided near the chuck table 8. The encoder 20 includes, for example, a light source that emits light (e.g., visible light) toward a scale formed on the lower surface of the bottom wall 10a of the frame body 10 of the chuck table 8, and a light receiving element that converts the light reflected on the lower surface of the bottom wall 10a into an electrical signal. The encoder 20 detects the rotation angle of the chuck table 8 based on this electrical signal.

[0032] The chuck table 8 is supported by an inclination adjustment mechanism (not shown) via a bearing (not shown) and a table base (not shown). The inclination adjustment mechanism includes, for example, two movable shafts and one fixed shaft arranged at substantially equal angular intervals along the circumferential direction of the chuck table 8. When at least one of the two movable shafts moves the table base and the chuck table 8 up and down partially, the inclination of the rotation axis of the chuck table 8 is adjusted.

[0033] An X-axis direction movement mechanism (not shown) is provided inside the recess 4a formed on the upper surface of the base 4. The X-axis direction movement mechanism includes, for example, a ball screw and a motor. When the X-axis direction movement mechanism is operated, the chuck table 8 moves between the loading / unloading position and the grinding position.

[0034] Around the chuck table 8, a rectangular table cover 22 that surrounds the chuck table 8 such that its holding surface is exposed is provided. The width of this table cover 22 (the length along the Y-axis direction) is approximately equal to the width of the depression 4a formed on the upper surface of the base 4. Further, dust and splash-proof covers 24 that are stretchable along the X-axis direction are provided in front of and behind the table cover 22.

[0035] On the upper surface of the base 4, a processing chamber cover 26 that surrounds the space (processing chamber) where the workpiece 11 is ground is provided. This processing chamber cover 26 has a rectangular top plate 28 whose width (the length along the Y-axis direction) is larger than that of the depression 4a. Note that this top plate 28 overlaps the rear side of the depression 4a in plan view.

[0036] And on the top plate 28, a circular opening 28a is formed that exposes the center and the rear end of the holding surface of the chuck table 8 whose center is located on the rear side of the top plate 28 and is positioned at the grinding position in plan view.

[0037] This opening 28a enables the grinding wheel 72, which will be described later, to enter and exit the processing chamber. Specifically, the opening 28a is formed such that its center in plan view overlaps the center of the grinding wheel 72 and its diameter is larger than the outer diameter of the grinding wheel 72.

[0038] The upper end of the front side plate 30 is fixed to the lower side of the front end portion of the top plate 28. And on the front side plate 30, a rectangular opening 30a is formed that enables the chuck table 8 that holds the workpiece 11 to enter and exit the processing chamber. In other words, the front side plate 30 has a gate-like shape, specifically, a shape in which the lower side of the portion overlapping the depression 4a is cut out.

[0039] Below the rear end portion, left end portion, and right end portion of the top plate 28, the upper end portions of the rear side plate 32, left side plate 34, and right side plate 36 are respectively fixed. Note that each of the rear side plate 32, left side plate 34, and right side plate 36 has a rectangular shape. Also, the lower end portions of each of the front side plate 30, rear side plate 32, left side plate 34, and right side plate 36 are fixed to the upper surface of the base 4.

[0040] Furthermore, the processing chamber cover 26 includes a partition plate 38 for partitioning the processing chamber into a space (grinding space) S1 where grinding of the workpiece 11 is performed and a space (imaging space) S2 where imaging of the ground workpiece 11 is performed.

[0041] Note that the partition plate 38 extends along the Y-axis direction and has a length approximately the same as that of the front side plate 30 and rear side plate 32. And the upper end portion, left end portion, and right end portion of the partition plate 38 are respectively fixed to the lower side of a portion of the top plate 28 slightly forward of the opening 28a, the inner side of the upper portion of the left side plate 34, and the inner side of the upper portion of the right side plate 36.

[0042] In the imaging space S2, an imaging unit 40 for imaging one surface 11a side of the workpiece 11 held on the holding surface of the chuck table 8 is provided. This imaging unit 40 is positioned forward when viewed from the center of the holding surface of the chuck table 8 positioned at the grinding position and has a rectangular top plate 40a that overlaps with the front side of this holding surface in plan view.

[0043] The top plate 40a of the imaging unit 40 is supported by the processing chamber cover 26 via four supports 42 provided so as to hang down from the top plate 28 of the processing chamber cover 26. And at the center of the top plate 40a of the imaging unit 40, a camera 40b with its objective lens directed downward is provided.

[0044] Also, light sources 40c are provided below each of the four end portions of the top plate 40a. Note that each light source 40c can emit light (for example, visible light) obliquely downward so that a position overlapping with the top plate 40a in plan view is illuminated.

[0045] Furthermore, in a direction opposite to the rotation direction of the chuck table 8 (the direction of arrow A1 shown in FIG. 3) as viewed from the camera 40b of the imaging unit 40, an air curtain (fluid injection unit) 44 is provided. This air curtain 44 is supported by the processing chamber cover 26 via a plurality of supports 46 provided so as to project forward from the partition plate 38 respectively.

[0046] And the air curtain 44 extends along the radial direction of the holding surface of the chuck table 8 positioned at the grinding position in plan view, and can inject air downward thereof. That is, this air curtain 44 can inject air toward the region that has entered from the grinding space S1 to the imaging space S2 on the holding surface of the chuck table 8.

[0047] As shown in FIG. 1, a square columnar support structure 48 is provided in a region of the upper surface of the base 4 located behind the depression 4a. A grinding unit 50 is provided on the front side of this support structure 48. This grinding unit 50 has a Z-axis direction movement mechanism 52 provided on the front surface of the support structure 48.

[0048] This Z-axis direction movement mechanism 52 includes a pair of guide rails 54 each extending along the Z-axis direction. And on the front side of each of the pair of guide rails 54, a slider (not shown) is provided in a slidable manner along the Z-axis direction. Also, the front end portion of this slider is fixed to the rear surface side of a rectangular parallelepiped Z-axis movement plate 56.

[0049] Furthermore, between the pair of guide rails 54, a screw shaft 58 extending along the Z-axis direction is arranged. And a motor 60 for rotating the screw shaft 58 is connected to the upper end portion of the screw shaft 58. Also, on the outer peripheral surface of the screw shaft 58 where the thread is formed, a nut (not shown) for accommodating balls that circulate in response to the rotation of the screw shaft 58 is provided, and a ball screw is configured.

[0050] Also, this nut is fixed to the rear surface side of the Z-axis moving plate 56. Therefore, when the screw shaft 58 is rotated by the motor 60, the Z-axis moving plate 56 moves along the Z-axis direction together with the nut. A cylindrical support member 62 is fixed to the front side of the Z-axis moving plate 56.

[0051] And inside the support member 62, a cylindrical spindle housing 64 extending along the Z-axis direction is provided. Also, inside the spindle housing 64, a spindle 68 is provided which is supported by the spindle housing 64 in a rotatable manner and whose upper end is connected to the motor 66 (see FIGS. 2 and 3).

[0052] The lower end of this spindle 68 protrudes from the spindle housing 64 and is fixed to a disk-shaped wheel mount 70. And on the lower surface side of the wheel mount 70, an annular grinding wheel 72 having an outer diameter approximately equal to the diameter of the wheel mount 70 is mounted using a fixing member (not shown) such as a bolt.

[0053] This grinding wheel 72 has a plurality of grinding grains 72a and a wheel base 72b having a lower surface on which the plurality of grinding grains 72a are arranged discretely in an annular shape. And when the motor 66 is operated, the wheel mount 70 and the grinding wheel 72 rotate around a straight line along the Z-axis direction as the rotation axis, for example, clockwise in a plan view (along the direction of arrow A2 shown in FIG. 3).

[0054] Note that the plurality of grinding grains 72a have abrasive grains such as diamond or cBN dispersed in a bonding material such as vitrified bond or resin bond. Also, the wheel base 72b is made of a metal material such as stainless steel or aluminum, for example.

[0055] Furthermore, a grinding fluid supply unit 74 is provided in the vicinity of the grinding wheel 72. This grinding fluid supply unit 74 has a pipe 76 inserted into a through hole formed in the rear side plate 32 of the processing chamber cover 26. And the base end portion (one end portion) of the pipe 76 is connected to a grinding fluid supply source (not shown).

[0056] Also, a nozzle 78 is provided at the tip end portion (the other end portion) of the pipe 76. When this grinding fluid supply unit 74 is operated, grinding fluid (for example, water) is supplied from the grinding fluid supply source through the pipe 76 and the nozzle 78 toward the rear side of the holding surface of the chuck table 8 positioned at the grinding position.

[0057] The grinding device 2 incorporates a controller that controls the holding unit 6, the grinding unit 50, the imaging unit 40, and the like. FIG. 4(A) is a block diagram schematically showing this controller. The controller 80 shown in FIG. 4(A) includes a processor 80a and a memory 80b.

[0058] The processor 80a is constituted by, for example, a CPU (Central Processing Unit) or the like. The memory 80b is constituted by, for example, a volatile memory such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory), and a non-volatile memory such as an SSD (Solid State Drive) (NAND type flash memory) or an HDD (Hard Disk Drive) (magnetic storage device).

[0059] And the processor 80a can read out and execute a program for grinding one surface 11a side of the workpiece 11 from the memory 80b. In addition to this program, the memory 80b can store data used when this program is being executed by the processor 80a.

[0060] For example, the memory 80b stores information regarding the altered layer used for determining whether to finish grinding one surface 11a side of the workpiece 11. Such information includes, for example, a threshold value for the ratio of the altered layer existing on one surface 11a side of the workpiece 11 or a threshold value for the period during which the presence of the altered layer is not confirmed in the imaged area of one surface 11a side of the workpiece 11, etc.

[0061] Also, the memory 80b may store information regarding the altered layer used for determining whether to change the grinding conditions when grinding one surface 11a side of the workpiece 11. Such information includes, for example, a table in which a plurality of different numerical ranges for the above ratio or period are respectively associated with a plurality of grinding conditions.

[0062] In this table, the larger one of the plurality of numerical ranges for the above ratio or the smaller one of the plurality of numerical ranges for the above period is associated with a grinding condition (for example, a grinding condition with a large downward speed (grinding feed rate) of the grinding wheel 72) that increases the load. In other words, in this table, the smaller one of the plurality of numerical ranges for the above ratio or the larger one of the plurality of numerical ranges for the above period is associated with a grinding condition (for example, a grinding condition with a small grinding feed rate) that reduces the load.

[0063] Also, the memory 80b may store information used for identifying the altered layer existing on one surface 11a side of the imaged workpiece 11. Such information includes, for example, the direction in which the altered layer extends, etc.

[0064] FIG. 4(B) is a block diagram schematically showing the functional parts embodied by the controller 80 when grinding one surface 11a side of the workpiece 11. Specifically, during this grinding, the information acquisition unit 80c and the grinding command unit 80d are embodied by the controller 80.

[0065] The information acquisition unit 80c acquires information regarding the altered layer on the one surface 11a side of the workpiece 11. Specifically, the information acquisition unit 80c first controls the imaging unit 40 to image the one surface 11a side of the workpiece 11 in a state parallel to or interrupted from the grinding of the one surface 11a side of the workpiece 11.

[0066] Once the one surface 11a side of the workpiece 11 is imaged, the information acquisition unit 80c identifies, for example, that an element linearly extending along a direction pre-stored in the one surface 11a side of the workpiece 11 is the altered layer. Note that this direction may be corrected according to the rotation angle of the chuck table 8 detected by the encoder 20. That is, the information acquisition unit 80c may identify that an element linearly extending along a direction changing according to the rotation angle of the chuck table 8 is the altered layer.

[0067] Once the altered layer existing on the one surface 11a side of the workpiece 11 is identified, the information acquisition unit 80c calculates, for example, the ratio of the altered layer existing on the one surface 11a side of the workpiece 11. Further, when the one surface 11a side of the workpiece 11 is imaged in parallel with the grinding of the one surface 11a side of the workpiece 11, the information acquisition unit 80c may measure the period during which the presence of the altered layer is not confirmed in the imaged area of the one surface 11a side of the workpiece 11.

[0068] The grinding command unit 80d refers to the information regarding the altered layer acquired by the information acquisition unit 80c (specifically, the ratio calculated or the period measured by the information acquisition unit 80c, etc.) and controls the grinding unit 50 so that the one surface 11a side of the workpiece 11 is appropriately ground. Specifically, the grinding command unit 80d includes a change unit 80e that determines whether to change the grinding conditions when grinding the one surface 11a side of the workpiece 11, and an end unit 80f that determines whether to end this grinding.

[0069] When the value of the ratio calculated by the information acquisition unit 80c or the value of the measured period is not included in the numerical range associated with the current grinding condition in a previously stored table, for example, the grinding unit 50 is controlled so that one surface 11a side of the workpiece 11 is ground under the grinding condition associated with the numerical range including this value.

[0070] When the value of the ratio calculated by the information acquisition unit 80c is smaller than the threshold value for the ratio of the altered layer stored in advance, or when the value of the period measured by the information acquisition unit 80c is larger than the threshold value for the period during which the presence of the altered layer is not confirmed, stored in advance, for example, the grinding unit 50 is controlled to end the grinding of one surface 11a side of the workpiece 11.

[0071] FIG. 5 is a flowchart schematically showing an example of a method for grinding a workpiece in which one surface 11a side of the workpiece 11 is ground in the grinding apparatus 2. In this method, first, the workpiece 11 is held so that one surface 11a side is exposed (holding step S10). FIG. 6(A) is a partial cross-sectional side view schematically showing the state of the holding step S10.

[0072] In this holding step S10, first, the chuck table 8 is positioned at the loading / unloading position. Next, the workpiece 11 is placed on the holding surface of the chuck table 8 so that one surface 11a faces upward and covers the porous plate 12.

[0073] Next, the suction source 16a is operated and the valve 14a is opened. In this case, a suction force acts on the workpiece 11 from the chuck table 8. Therefore, the workpiece 11 is held on the holding surface of the chuck table 8 with one surface 11a side exposed.

[0074] Next, the chuck table 8 is positioned at the grinding position. Thereby, the holding step S10 is completed. After the holding step S10, one surface 11a side of the workpiece 11 is ground (grinding step S20). FIG. 6(B) is a partial cross-sectional side view schematically showing the state of the grinding step S20.

[0075] In this grinding process S20, while rotating both the chuck table 8 and the grinding wheel 72, the grinding wheel 72 is lowered so that a plurality of grinding wheels 72a come into contact with one surface 11a of the workpiece 11. Further, immediately before this grinding, the supply of the grinding fluid L from the nozzle 78 of the grinding fluid supply unit 74, the injection of air from the air curtain 44, and the imaging by the camera 40b in a state where light is emitted from each light source 40c of the imaging unit 40 are started.

[0076] Thereby, grinding of the one surface 11a side of the workpiece 11 in a state where the grinding fluid L is supplied to the contact interface (processing point) between the plurality of grinding wheels 72a and the one surface 11a of the workpiece 11, and imaging of the one surface 11a side of the workpiece 11 in a state where the entry of the grinding fluid L between the camera 40b and the one surface 11a of the workpiece 11 is suppressed are performed in parallel.

[0077] Then, in the grinding process S20, based on the imaging of the one surface 11a side of the workpiece 11, the controller 80 repeatedly makes a determination as to whether or not to change the grinding conditions when grinding the one surface 11a side of the workpiece 11, and a determination as to whether or not to end this grinding. FIG. 7 is a flowchart schematically showing an example of the processing performed by the controller 80 for making these determinations.

[0078] Specifically, the controller 80 first acquires information regarding the altered layer (acquisition step S21). In this acquisition step S21, an image formed by the camera 40b imaging the one surface 11a side of the workpiece 11 immediately before is referred to.

[0079] Note that the controller 80 may perform various processes on this image prior to the acquisition step S21. Examples of this process include rotation according to the rotation angle of the chuck table 8 detected by the encoder 20, or extraction using Fourier transform of a pattern corresponding to the altered layer formed at a predetermined period.

[0080] FIG. 8(A) is a plan view schematically showing one surface 11a side of the workpiece 11 before grinding. On the one surface 11a side of the workpiece 11, for example, a plurality of altered layers 13 each extending along a direction orthogonal to the orientation flat 11c are present at substantially equal intervals in a plan view.

[0081] Also, a plurality of altered layers 13 similarly exist in the image I1 formed by imaging the one surface 11a side of the workpiece 11. Therefore, the controller 80 can acquire information regarding the altered layer 13 (for example, the value of the ratio of the altered layer 13 existing on the one surface 11a side of the workpiece 11 and / or the value of the period during which the presence of the altered layer 13 is not confirmed in the imaged area of the one surface 11a side of the workpiece 11) by referring to this image I1.

[0082] And if the grinding conditions (for example, the grinding feed rate) are not appropriate in light of the information regarding the altered layer 13 acquired by referring to the image I1 (for example, if the acquired ratio value and / or period value are not included in the numerical range associated with the current grinding conditions in a previously stored table) (Change determination step S22: NO), the controller 80 changes the grinding conditions to appropriate ones (for example, the grinding conditions associated with the numerical range including these values) (Change step S23), and then re - executes the acquisition step S21.

[0083] FIG. 8(B) is a plan view schematically showing one surface 11a side of the workpiece 11 in which a part of the altered layer 13 has been removed by grinding. On the one surface 11a side of this workpiece 11, for example, the number of the altered layers 13 decreases, and new grinding marks (saw marks), specifically, periodic unevenness due to grinding are formed. Also, in the image I2 formed by imaging the one surface 11a side of the workpiece 11, the number of the altered layers 13 decreases and new grinding marks appear.

[0084] Note that the controller 80 uses information (e.g., the direction in which the altered layer 13 extends) that is pre-stored and used for identifying the altered layer 13 to identify that the newly emerged grinding marks are not the altered layer 13. Therefore, the controller 80 can accurately obtain new information regarding the altered layer 13, that is, can accurately update this information, by referring to the image I2 using the information used for identifying the altered layer 13.

[0085] Then, if the grinding conditions are not appropriate in light of the information regarding the altered layer 13 obtained by referring to the image I2 (Change determination step S22: NO), the controller 80 re-executes the change step S23 and the acquisition step S21. Also, even if the grinding conditions are appropriate in light of this information (Change determination step S22: YES), if grinding of the one surface 11a side of the workpiece 11 is necessary in light of this information (for example, if the value of the ratio obtained is greater than the threshold value for the ratio of the pre-stored altered layer 13, or if the value of the period obtained is smaller than the threshold value for the period during which the presence of the pre-stored altered layer 13 is not confirmed) (End determination step S24: YES), the controller 80 re-executes the acquisition step S21.

[0086] FIG. 8(C) is a plan view schematically showing the one surface 11a side of the workpiece 11 from which most of the altered layer 13 has been removed by grinding. On the one surface 11a side of this workpiece 11, for example, the number of altered layers 13 further decreases, and each altered layer 13 is subdivided. Also, in the image I3 formed by imaging the one surface 11a side of the workpiece 11, the number of altered layers 13 further decreases, and each altered layer 13 is subdivided.

[0087] Then, if the grinding conditions are not appropriate in light of the information regarding the altered layer 13 obtained by referring to the image I3 (Change determination step S22: NO), the controller 80 re-performs the change step S23 and the acquisition step S21. Also, even if the grinding conditions are appropriate in light of this information (Change determination step S22: YES), if grinding of the one surface 11a side of the workpiece 11 is necessary in light of this information (End determination step S24: YES), the controller 80 re-performs the acquisition step S21.

[0088] In addition, when it is assumed that, for example, the one surface 11a side of the workpiece 11 is polished after the grinding step S20, it is not necessary for all of the altered layer 13 to be removed in the grinding step S20. In this case, the threshold value for the ratio of the altered layer 13 may be set relatively large, or the threshold value for the period during which the presence of the altered layer 13 is not confirmed may be set relatively small.

[0089] And even when information regarding the altered layer 13 is obtained by referring to the image I3, if grinding of the one surface 11a side of the workpiece 11 is not necessary in light of this information (for example, if the value of the ratio obtained is smaller than the threshold value for the ratio of the altered layer 13 stored in advance, or if the value of the period obtained is larger than the threshold value for the period during which the presence of the altered layer 13 stored in advance is not confirmed) (End determination step S24: NO), the controller 80 ends the grinding step S20 (End step S25).

[0090] FIG. 8(D) is a plan view schematically showing the one surface 11a side of the workpiece 11 from which all of the altered layer 13 has been removed by grinding. On the one surface 11a side of this workpiece 11, for example, only the grinding marks 15 remain. Also, in the image I4 formed by imaging the one surface 11a side of the workpiece 11, only the grinding marks 15 remain.

[0091] In addition, at the end of the grinding process S20, when it is assumed that the grinding marks 15 are removed, that is, the surface is flattened so that there are no periodic unevennesses caused by grinding, the grinding conditions may be changed after all of the heat-affected layer 13 has been removed by grinding. In this case, for example, a threshold value for a period during which the presence of the relatively thick heat-affected layer 13 is not confirmed is used to determine whether or not to finish grinding the one surface 11a side of the workpiece 11.

[0092] And even when information regarding the heat-affected layer 13 is obtained with reference to the image I4, if the grinding conditions are not appropriate in light of this information (change determination step S22: NO), the controller 80 re-executes the change step S23 and the acquisition step S21 and then executes the end step S25.

[0093] In the grinding apparatus 2, as described above, based on information regarding the heat-affected layer 13 obtained from imaging of the one surface 11a side of the workpiece 11, which is carried out in parallel with grinding of the one surface 11a side of the workpiece 11, it is determined whether or not to finish grinding the one surface 11a side of the workpiece 11. In this case, an appropriate thickness of the one surface 11a side of the workpiece 11 can be removed without excess or deficiency.

[0094] Specifically, in this case, without excessively grinding the one surface 11a side of the workpiece 11, for example, when it is determined that all of the heat-affected layer 13 has been removed, grinding of the one surface 11a side of the workpiece 11 can be finished. Therefore, in the grinding apparatus 2, it is possible to suppress a decrease in the productivity of the semiconductor device manufactured using the workpiece 11 and to suppress a decrease in its throughput.

[0095] Note that the above-described content is one aspect of the present invention, and the present invention is not limited to the above-described content. For example, in the present invention, instead of being carried out in parallel with grinding of the one surface 11a side of the workpiece 11, it may be interrupted, and a determination as to whether or not to change the grinding conditions (change determination step S22) when grinding the one surface 11a side of the workpiece 11 and a determination as to whether or not to finish this grinding (end determination step S24) may be carried out.

[0096] Further, in the present invention, without performing a determination as to whether or not to change the grinding conditions (change determination step S22) when grinding the one surface 11a side of the workpiece 11 in parallel with or interrupting the grinding of the one surface 11a side of the workpiece 11, a determination as to whether or not to end this grinding (end determination step S24) may be performed.

[0097] Further, in the present invention, an imaging unit having a structure different from that of the imaging unit 40 may be provided. FIG. 9 is a partial cross-sectional side view schematically showing an example of a grinding apparatus including an imaging unit having a structure different from that of the imaging unit 40.

[0098] The grinding apparatus 82 shown in FIG. 9 has the same structure as the grinding apparatus 2 except that the imaging unit 40 is replaced with the imaging unit 84. Further, the imaging unit 84 has a top plate 84a and a camera 84b similar to the top plate 40a and the camera 40b of the imaging unit 40.

[0099] Furthermore, the imaging unit 84 includes an annular light source 84c provided on the lower surface of the top plate 84a so as to surround the lower surface of the camera 84b and capable of emitting downward light, and mirrors 84d provided on the lower sides of the four ends of the top plate 84a. Each mirror 84d is generally thinner than each light source 40c included in the imaging unit 40.

[0100] The grinding apparatus 82 is preferable in that the imaging field of view of the camera 84b can be widened as compared with the grinding apparatus 2. On the other hand, the grinding apparatus 2 is preferable in that the shape of the one surface 11a side of the workpiece 11 (for example, periodic unevenness caused by grinding) is more likely to be reflected in the image formed by imaging with the camera 84b as compared with the grinding apparatus 82.

[0101] Further, in the present invention, the one surface 11a side of the workpiece 11 may be imaged in a state where the imaging space S2 is filled with a liquid. Each of FIGS. 10(A) and 11(A) is a partial cross-sectional side view schematically showing an example of a grinding apparatus capable of imaging the one surface 11a side of the workpiece 11 in this manner.

[0102] The grinding device 86 shown in FIG. 10(A) has the same structure as the grinding device 2, except that the imaging unit 40 is replaced by the imaging unit 88 and the air curtain 44 is not provided. Further, the imaging unit 88 has a top plate 88a, a camera 88b, and a light source 88c similar to the top plate 40a, the camera 40b, and the light source 40c of the imaging unit 40.

[0103] Furthermore, the imaging unit 88 has a rectangular light-transmitting member 88d made of a material (e.g., glass) through which the light emitted from the light source 88c passes. This light-transmitting member 88d is located slightly below the light source 88c, and one end thereof is fixed to the lower end of the partition plate 38 of the processing chamber cover 26. FIG. 10(B) is a partial cross-sectional side view schematically showing the state of the grinding process S20 performed in the grinding device 86.

[0104] In this grinding process S20, while rotating both the chuck table 8 and the grinding wheel 72, the grinding wheel 72 is lowered so that the plurality of grinding wheels 72a come into contact with one surface 11a of the workpiece 11. Further, immediately before this grinding, the supply of the grinding fluid L from the nozzle 78 of the grinding fluid supply unit 74 and the imaging by the camera 40b in a state where light is emitted from each light source 40c of the imaging unit 40 are started.

[0105] Thereby, the grinding on the one surface 11a side of the workpiece 11 in a state where the grinding fluid L is supplied to the machining point and the imaging on the one surface 11a side of the workpiece 11 in a state where the grinding fluid L has entered between the light-transmitting member 88d and the one surface 11a of the workpiece 11, that is, in a state where the imaging space S2 is filled with the grinding fluid L, are performed in parallel.

[0106] Since the grinding device 86 does not include the air curtain 44 as compared with the grinding device 2, its structure is simplified and inexpensive, and no mist is generated due to air being injected into the grinding fluid L. Therefore, it is preferable in that this mist does not mix into the imaging space S2 and the accuracy of the image formed by imaging with the camera 84b does not decrease. On the other hand, since it is not necessary to fill the imaging space S2 with the grinding fluid L in the grinding device 2 as compared with the grinding device 82, the degree of freedom in the grinding conditions (particularly, the supply conditions of the grinding fluid L) when grinding one surface 11a side of the workpiece 11 is increased, which is preferable.

[0107] The grinding device 90 shown in FIG. 11(A) has the same structure as the grinding device 2 except that the imaging unit 40 is replaced with the imaging unit 92 and the support 42 provided to hang down from the top plate 28 is replaced with a longer support 94. Further, the imaging unit 92 has a top plate 92a, a camera 92b, and a light source 92c similar to the top plate 40a, the camera 40b, and the light source 40c of the imaging unit 40.

[0108] However, a through hole is formed in the top plate 92a, and the tip of the pipe 92d is connected to the upper surface of the top plate 92a so as to communicate with this through hole. Then, this pipe 92d is inserted into the through hole formed in the top plate 28 of the processing chamber cover 26, and its base end is connected to a water supply source (not shown). FIG. 11(B) is a partial cross-sectional side view schematically showing the state of the grinding process S20 performed in the grinding device 90.

[0109] In this grinding process S20, while rotating both the chuck table 8 and the grinding wheel 72, the grinding wheel 72 is lowered so that the plurality of grinding wheels 72a contact one surface 11a of the workpiece 11. Further, immediately before this grinding, the supply of the grinding fluid L from the nozzle 78 of the grinding fluid supply unit 74, the injection of air from the air curtain 44, the imaging by the camera 92b in a state where light is emitted from each light source 92c of the imaging unit 92, and the supply of water W from the water supply source via the pipe 92d are started.

[0110] This allows for simultaneous grinding of the one surface 11a of the workpiece 11 when grinding fluid L is supplied to the contact interface (processing point) between the multiple grinding wheels 72a and one surface 11a of the workpiece 11, and imaging of the one surface 11a of the workpiece 11 when the intrusion of grinding fluid L between the camera 40b and the one surface 11a of the workpiece 11 is suppressed and water W is supplied, i.e., when the imaging space S2 is filled with grinding fluid L.

[0111] The grinding device 90 is preferable compared to the grinding device 2 in that it can reduce the likelihood that mist generated by spraying air into the grinding fluid L and grinding chips generated by grinding one surface 11a of the workpiece 11 will be mixed into the imaging space S2, thereby suppressing a decrease in the accuracy of the image formed by imaging by the camera 84b. On the other hand, the grinding device 2 is preferable compared to the grinding device 90 in that it does not include the piping 92d and the water supply source, and therefore has a simplified structure and is inexpensive.

[0112] Furthermore, in the present invention, a fluid ejection unit having a structure different from that of the air curtain 44 may be provided. For example, the fluid ejection unit of the present invention may include, instead of the air curtain 44, a nozzle capable of ejecting a fluid (e.g., air or water) toward the holding surface of the chuck table 8.

[0113] The present invention may also be a substrate manufacturing method for manufacturing a substrate having a thickness less than a predetermined thickness from an ingot having a predetermined thickness. The thickness of the ingot is not limited. For example, the thickness of the ingot may be submillimeter (e.g., 0.3 mm), several millimeters (e.g., 3 mm), several centimeters (e.g., 3 cm), or several tens of centimeters (e.g., 30 cm). FIG. 12 is a flow chart schematically showing an example of a substrate manufacturing method. In this method, first, an affected layer is formed inside the ingot (affected layer forming step S30).

[0114] Fig. 13 is a perspective view schematically illustrating the affected layer forming step S30. Note that the U-axis direction and V-axis direction shown in Fig. 13 are directions perpendicular to each other on a horizontal plane, and the W-axis direction is a direction (vertical direction) perpendicular to the U-axis direction and V-axis direction.

[0115] This affected layer forming step S30 is performed in a laser processing device 96. The laser processing device 96 includes a chuck table 98 having a circular holding surface that is approximately parallel to a horizontal plane and that can hold the ingot 17 on this holding surface.

[0116] The chuck table 98 is connected to a suction mechanism (not shown). This suction mechanism includes, for example, an ejector. When the suction mechanism operates, a suction force acts on the space near the holding surface of the chuck table 98. Therefore, when the suction mechanism operates with the ingot 17 placed on the holding surface, the ingot 17 is held on the holding surface of the chuck table 98.

[0117] The chuck table 98 is also connected to a rotation mechanism (not shown). This rotation mechanism includes, for example, a pulley and a motor. When the rotation mechanism operates, the chuck table 98 rotates around a rotation axis that passes through the center of the holding surface and is a straight line along the W-axis direction. For example, the rotation mechanism rotates the chuck table 98 so that the orientation flat 17a of the ingot 17 held on the holding surface of the chuck table 98 is parallel to the Y-axis direction.

[0118] The chuck table 98 is connected to a movement mechanism (not shown). This movement mechanism includes, for example, a ball screw and a motor. When the movement mechanism operates, the chuck table 98 moves along the U-axis direction, the V-axis direction, and / or the W-axis direction.

[0119] Above the chuck table 98, a head 102 of the laser beam irradiation unit 100 is provided. This head 102 is provided at the tip of a cylindrical housing 104 extending along the Y-axis direction. Note that the head 102 houses an optical system such as a condenser lens and a mirror, and the housing 104 houses an optical system such as a mirror and / or a lens.

[0120] Further, the laser beam irradiation unit 100 has, for example, a laser oscillator (not shown) including Nd:YAG or the like as a laser medium. This laser oscillator generates a pulsed laser beam LB having a wavelength (for example, 1030 nm or 1064 nm) that penetrates the material of the ingot 17 (for example, a single crystal such as Si, SiC, GaN, LT, or LN). Then, after the output (power) of the laser beam LB is adjusted by an attenuator (not shown), it is emitted downward directly from the head 102 through the optical system housed in the housing 104 and the head 102.

[0121] Furthermore, an imaging unit 106 capable of imaging the region directly below is provided on the side of the housing 104. This imaging unit 106 has, for example, a light source such as an LED (Light Emitting Diode), an objective lens, and an imaging element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0122] When performing the altered layer formation step S30 in the laser processing apparatus 96, the ingot 17 is placed on the holding surface of the chuck table 98. Next, the suction mechanism is operated so that the ingot 17 is held on the holding surface of the chuck table 98. Next, the imaging unit 106 is operated to form an image of the surface of the ingot 17.

[0123] Next, referring to this image, the rotation mechanism rotates the chuck table 98 so that, for example, the orientation flat 17a is parallel to the V-axis direction. Then, the moving mechanism moves the chuck table 98 along the U-axis direction and / or the V-axis direction so that a region near one end in the V-axis direction of the ingot 17 is positioned in the U-axis direction as viewed in plan from the head 102.

[0124] Next, the moving mechanism moves the chuck table 98 along the Z-axis direction so that the condensing point where the laser beam LB emitted from the head 102 is condensed is positioned at a predetermined depth corresponding to the thickness of the substrate manufactured from the ingot 17 from the surface of the ingot 17. Then, while emitting the laser beam LB from the head 102, the moving mechanism moves the chuck table 98 along the U-axis direction so that the condensing point where the laser beam LB is condensed passes from one end to the other end in the U-axis direction of the ingot 17.

[0125] That is, the ingot 17 is irradiated with the laser beam LB with the direction orthogonal to the orientation flat 17a as the scanning direction of the laser beam LB. Thereby, an altered layer 19 in which the crystal structure of the material is disturbed is formed inside the ingot 17 centering on the condensing point where the laser beam LB is condensed.

[0126] Next, in plan view, the moving mechanism moves the chuck table 98 along the V-axis direction so that the head 102 is positioned in the X-axis direction as viewed from a region slightly inside the region of the ingot 17 that has already been irradiated with the laser beam LB. Then, the ingot 17 is irradiated with the laser beam LB as described above with the direction opposite to the U-axis direction as the scanning direction of the laser beam LB.

[0127] Furthermore, the above-described operation is repeated until irradiation of the laser beam LB is completed on the region near the other end in the V-axis direction of the ingot 17. That is, the relative movement of the ingot 17 along the V-axis direction and the position where the focal point of the laser beam LB is formed (specifically, movement of the chuck table 98) and the irradiation of the ingot 17 with the laser beam LB scanning in the U-axis direction or the opposite direction are alternately repeated.

[0128] As a result, a plurality of rows of affected layers 19, each of which is perpendicular to the orientation flat 17a, are formed inside the ingot 17. This completes the affected layer forming step S30.

[0129] After the affected layer forming step S30, the ingot 17 is separated from the affected layer 19 as a starting point to manufacture a substrate (substrate manufacturing step S40). Figures 14(A) and 14(B) are side views each showing a schematic view of the substrate manufacturing step S40.

[0130] This substrate manufacturing process S40 is carried out in a separation apparatus 108. The separation apparatus 108 includes a chuck table 110 having a structure similar to that of the chuck table 98 shown in FIG.

[0131] The chuck table 110 is connected to a table-side suction mechanism (not shown). This table-side suction mechanism includes, for example, a vacuum pump. When this table-side suction mechanism operates, a suction force acts on the space near the holding surface of the chuck table 110. Therefore, when the table-side suction mechanism operates with the ingot 17 placed on the holding surface, the ingot 17 is held on the holding surface of the chuck table 110.

[0132] Above the chuck table 110, a separation unit 112 is provided. This separation unit 112 has a suction plate 114 having a plurality of suction ports formed on the lower surface. Each suction port communicates with a separation unit side suction mechanism (not shown) such as a vacuum pump through a suction passage formed inside the suction plate 114. When the separation unit side suction mechanism operates, a suction force acts on the space near the lower surface of the suction plate 114.

[0133] Also, a vertical movement mechanism 116 is connected to the upper surface of the suction plate 114. This vertical movement mechanism 116 has, for example, a ball screw and a motor. When the vertical movement mechanism 116 operates, the suction plate 114 moves along the vertical direction.

[0134] When performing the substrate manufacturing process S40 in the separation device 108, first, with the chuck table 110 and the suction plate 114 sufficiently separated, the ingot 17 having the altered layer 19 formed therein is placed on the holding surface of the chuck table 110 with the surface facing upward. Next, the table side suction mechanism is operated so that the ingot 17 is held on the holding surface of the chuck table 110.

[0135] Next, the vertical movement mechanism 116 lowers the suction plate 114 so that the lower surface of the suction plate 114 contacts the surface of the ingot 17 (see FIG. 14(A)). Next, the separation unit side suction mechanism is operated so that the surface side of the ingot 17 is sucked upward. Next, the vertical movement mechanism 116 raises the suction plate 114 so as to separate the suction plate 114 from the chuck table 110 (see FIG. 14(B)).

[0136] As a result, an external force that separates the front surface side and the back surface side of the ingot 17 is applied to the ingot 17. As a result, cracks propagate from the altered layer 19 and the ingot 17 separates, that is, the ingot 17 separates starting from the altered layer 19, and a substrate 21 having the altered layer 19 remaining on one surface 21a side is manufactured. Thus, the substrate manufacturing process S40 is completed.

[0137] After the substrate manufacturing step S40, one surface 21a side of the substrate 21 is ground (grinding step S50). Since this grinding step S50 is carried out in the same manner as the above-described grinding step S20, detailed description thereof will be omitted.

[0138] In addition, the structures, methods, and the like according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

Explanation of Signs

[0139] 2: Grinding device 4: Base (4a: Depression) 6: Holding unit 8: Chuck table 10: Frame body (10a: Bottom wall, 10b: Side wall, 10c: Flow path) 11: Workpiece (11a: One surface, 11b: The other surface) (11c: Orientation flat) 12: Porous plate 13: Modified layer 14a, 14b: Valve 15: Grinding mark 16a: Suction source 16b: Fluid supply source 17: Ingot (17a: Orientation flat) 18: Motor 19: Modified layer 20: Encoder 21: Substrate (21a: One surface) 22: Table cover 24: Dust and splash-proof cover 26: Processing chamber cover 28: Top plate (28a: Opening) 30: Front side plate (30a: Opening) 32: Rear side plate 34: Left side plate 36: Right side plate 38: Partition plate 40: Imaging unit (40a: Top plate, 40b: Camera, 40c: Light source) 42: Support tool 44: Air curtain (fluid injection unit) 46: Support tool 48: Support structure 50: Grinding unit 52: Z-axis movement mechanism 54: Guide rail 56: Z-axis movement plate 58: Screw shaft 60: Motor 62: Support member 64: Spindle housing 66: Motor 68: Spindle 70: Wheel mount 72: Grinding wheel (72a: Grinding stone, 72b: Wheel base) 74: Grinding fluid supply unit 76: Pipe 78: Nozzle 80: Controller (80a: Processor, 80b: Memory, 80c: Information acquisition unit) (80d: Grinding command unit, 80e: Change unit, 80f: End unit) 82: Grinding device 84: Imaging unit (84a: Top plate, 84b: Camera) (84c: Light source, 84d: Mirror) 86: Grinding device 88: Imaging unit (88a: Top plate, 88b: Camera) (88c: Light source, 88d: Translucent member) 90: Grinding device 92: Imaging unit (92a: Top plate, 92b: Camera) (92c: Light source, 92d: Pipe) 94: Support tool 96: Laser processing device 98: Chuck table 100: Laser beam irradiation unit 102: Head 104: Housing 106: Imaging unit 108: Separation device 110: Chuck table 112: Separation unit 114: Suction plate 116: Vertical movement mechanism

Claims

1. A grinding device for grinding one side of a workpiece having a deteriorated layer on one side thereof, comprising: a holding unit for holding the workpiece so that the one side is exposed; a grinding unit for grinding the one side of the workpiece held by the holding unit; an imaging unit for imaging the one side of the workpiece held by the holding unit; a controller for determining whether to end the grinding of the one side of the workpiece by referring to information regarding the deteriorated layer obtained based on imaging of the one side of the workpiece, which is performed in parallel with or after interruption of the grinding of the one side of the workpiece; A grinding device comprising the above components.

2. The grinding device further comprises a processing chamber cover surrounding a processing chamber capable of accommodating the workpiece held by the holding unit, the grinding unit, and the imaging unit, wherein the processing chamber cover includes a partition plate for partitioning the processing chamber into a grinding space where grinding of the one side of the workpiece is performed and an imaging space where imaging of the one side of the workpiece is performed. The grinding device according to claim 1.

3. a grinding fluid supply unit for supplying grinding fluid to a region to be ground on the one side of the workpiece; a fluid injection unit for injecting fluid so as not to allow the grinding fluid to enter a region to be imaged on the one side of the workpiece; The grinding device according to claim 1 or claim 2, further comprising the above components.

4. The holding unit includes a chuck table for holding the workpiece on a holding surface, a motor for rotating the chuck table with a straight line passing through the center of the holding surface as a rotation axis, and an encoder for detecting the rotation angle of the chuck table. The controller identifies that an element linearly extending along a direction that changes according to the rotation angle in the workpiece imaged by the imaging unit is the deteriorated layer. The grinding device according to claim 1 or claim 2.

5. The controller changes grinding conditions by referring to the information during grinding of the one side of the workpiece. The grinding device according to claim 1 or claim 2.

6. A method for grinding a workpiece having a deteriorated layer on one side thereof, the method for grinding the one side of the workpiece comprising: a holding step of holding the workpiece so that the one side is exposed; a grinding step of grinding the one side of the workpiece after the holding step. Whether to end the grinding process is determined by referring to information regarding the altered layer obtained based on imaging of one surface side of the workpiece, which is carried out in parallel with or interrupting the grinding of the one surface side of the workpiece. A method for grinding a workpiece.

7. A method for manufacturing a substrate for manufacturing a substrate having a thickness less than a predetermined thickness from an ingot having a predetermined thickness, By relatively moving the ingot and the condensing point while positioning the condensing point where a laser beam having a wavelength that penetrates the material of the ingot is condensed inside the ingot, an altered layer forming step of forming an altered layer inside the ingot; After the altered layer forming step, a substrate manufacturing step of manufacturing the substrate having the altered layer remaining on one surface side thereof by separating the ingot starting from the altered layer; After the substrate manufacturing step, a grinding step of grinding one surface side of the substrate, comprising: Whether to end the grinding step is determined by referring to information regarding the altered layer obtained based on imaging of one surface side of the substrate, which is carried out in parallel with or interrupting the grinding of the one surface side of the substrate. A method for manufacturing a substrate.

Images