Machining method and machining device for workpiece

Abstract

To provide a new machining method for a workpiece that can minimize the possibilities of adhesion of foreign matters to a trimmed portion and peeling of a film from the trimmed portion.SOLUTION: A machining method for a workpiece includes: a holding step of holding, on an upper surface of a chuck table, a second substrate side of the workpiece having a structure in which a second substrate is bonded to a first substrate; a trimming step of, after the holding step, causing an annular cutting blade having an outer peripheral surface and a side surface to cut into the workpiece along an outer edge of the workpiece from a first substrate side to a depth reaching the second substrate while rotating the cutting blade, thereby forming a trimmed portion along the outer edge of the workpiece, the trimmed portion having a bottom surface in contact with the outer peripheral surface of the cutting blade and a side surface in contact with the side surface of the cutting blade; and a polishing step of polishing the bottom surface and the side surface of the trimmed portion with a polishing pad.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for processing a workpiece used when processing a workpiece having a structure in which a second substrate is bonded to a first substrate. [Background technology]

[0002] To realize small and lightweight device chips, there are increasing opportunities to thin disk-shaped wafers with devices such as integrated circuits (ICs) mounted on their front side. For example, the front side of the wafer is held by a chuck table, and the chuck table and a grinding tool with a grinding wheel containing abrasive grains are rotated relative to each other, and the grinding wheel is pressed against the back side of the wafer while a liquid such as pure water is supplied, thereby grinding the wafer to make it thinner.

[0003] The outer edge of a disk-shaped wafer used in the manufacture of device chips is usually chamfered to prevent the wafer from chipping or cracking due to impacts during transportation, etc. However, when a wafer with a chamfered outer edge is thinned by grinding or other methods, the outer edge of the wafer becomes sharp and brittle like a knife edge, making the wafer more susceptible to chipping or cracking.

[0004] Therefore, before grinding the wafer, a process called edge trimming is performed to remove the chamfered portion (hereinafter referred to as the chamfered portion) (see, for example, Patent Document 1). If the chamfered portion is removed by cutting a cutting blade into the wafer, the outer edge of the wafer will not become sharp and brittle even when the wafer is ground from the back side.

[0005] However, if an attempt is made to completely remove the chamfer of a thick workpiece having a structure in which multiple wafers are bonded together by edge trimming, the cutting blade will be significantly worn and its lifespan will be extremely shortened. For this reason, when processing a thick workpiece by edge trimming, the chamfer is often not completely removed in the thickness direction of the workpiece, and a portion of the back side is left. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-173961 Summary of the Invention [Problem to be solved by the invention]

[0007] The machined surface (hereinafter referred to as the "machined surface") of the chamfered portion (hereinafter referred to as the "trimmed portion") remaining after the above-described edge trimming has a roughness that depends on the size of the abrasive grains that make up the cutting blade, and is generally rough to a certain extent. Therefore, foreign matter such as chips generated during the machining of the workpiece is likely to adhere to the machined surface of the trimmed portion. Furthermore, if a film is later formed on the workpiece, there is also the problem that the film is likely to peel off from the machined surface of the trimmed portion.

[0008] In contrast, if edge trimming is performed using a cutting blade made of small abrasive grains, the processed surface of the trimmed portion can be smoothed and foreign matter adhesion and peeling of the film can be prevented to a certain extent. However, in this case, the workpiece is difficult to cut due to the small abrasive grains, so the cutting blade is easily worn. Therefore, the life of the cutting blade is also shortened.

[0009] Therefore, an object of the present invention is to provide a new workpiece processing method and processing apparatus that can reduce the possibility of foreign matter adhering to the trimmed portion or of a film peeling off from the trimmed portion. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided a method for processing a workpiece, the method including: a holding step in which the second substrate side of a workpiece having a structure in which a second substrate is bonded to a first substrate is held on the upper surface of a chuck table; a trimming step in which, after the holding step, an annular cutting blade having an outer peripheral surface and a side surface is rotated and the cutting blade is caused to cut along the outer edge of the workpiece from the first substrate side to a depth reaching the second substrate, thereby forming a trimmed portion along the outer edge of the workpiece, the trimmed portion having a bottom surface contacted by the outer peripheral surface of the cutting blade and a side surface contacted by the side surface of the cutting blade; and a polishing step in which the bottom surface and the side surface of the trimmed portion are polished with a polishing pad.

[0011] Preferably, in the polishing step, the disc-shaped polishing pad having an outer peripheral surface and a bottom surface is rotated while the bottom surface of the polishing pad is brought into contact with the bottom surface of the portion to be trimmed and the outer peripheral surface of the polishing pad is brought into contact with the side surface of the portion to be trimmed.

[0012] Preferably, the height of the outer peripheral surface of the polishing pad is greater than the height of the side surface of the trimmed portion, the diameter of the bottom surface of the polishing pad is greater than the width of the bottom surface of the trimmed portion, and in the polishing step, the polishing pad is pressed against the bottom surface and the side surface of the trimmed portion.

[0013] Preferably, after the trimming step, the method further includes a cleaning step of holding the workpiece so that the second substrate side is exposed and cleaning the second substrate side of the workpiece, and the polishing step is performed while the cleaning step is being performed.

[0014] Preferably, the method further includes, after the polishing step, a film forming step of forming a film on the bottom surface of the trimmed portion.

[0015] According to another aspect of the present invention, there is provided a processing apparatus including: a chuck table having an upper surface capable of holding the second substrate side of a workpiece having a structure in which a second substrate is bonded to a first substrate; a rotation mechanism for rotating the chuck table around an axis intersecting a plane including the upper surface; a cutting mechanism having a rotation shaft to which an annular cutting blade having an outer peripheral surface and a side surface is attached; and a polishing unit to which a polishing pad is attached for polishing the bottom surface and the side surface of an annular trimmed portion formed along the outer edge of the workpiece by the cutting mechanism, the annular trimmed portion having a bottom surface in contact with the outer peripheral surface of the cutting blade and a side surface in contact with the side surface of the cutting blade.

[0016] Preferably, the polishing unit has a rotating shaft on which the disc-shaped polishing pad having an outer peripheral surface and a bottom surface is mounted, and while rotating the polishing pad, the bottom surface of the polishing pad is brought into contact with the bottom surface of the trimmed portion, and the outer peripheral surface of the polishing pad is brought into contact with the side surface of the trimmed portion.

[0017] Preferably, the polishing pad further includes a moving mechanism that moves the polishing pad so as to press the polishing pad against the bottom surface and the side surface of the trimmed portion, wherein the height of the outer peripheral surface of the polishing pad is greater than the height of the side surface of the trimmed portion, and the diameter of the bottom surface of the polishing pad is greater than the width of the bottom surface of the trimmed portion.

[0018] Preferably, the apparatus further includes a holder that holds the workpiece so that the second substrate side is exposed, and a cleaning unit that cleans the second substrate side of the workpiece. [Effects of the Invention]

[0019] According to a workpiece processing method according to one aspect of the present invention and a processing apparatus according to another aspect, the bottom and side surfaces of the trimmed portion formed on the workpiece are polished by a polishing pad, making the bottom and side surfaces of the trimmed portion smoother than when they are not polished by a polishing pad.

[0020] This makes it less likely for foreign matter to adhere to the trimmed portion and for a film to peel off from the trimmed portion than when the bottom and side surfaces of the trimmed portion are not polished. Therefore, the workpiece processing method according to one aspect of the present invention and the processing apparatus according to another aspect can reduce the possibility of foreign matter adhering to the trimmed portion and a film peeling off from the trimmed portion. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view showing a processing device. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a workpiece. [Figure 3] FIG. 3 is a perspective view schematically showing the chuck table and the like. [Figure 4] FIG. 4 is a perspective view schematically showing the underside cleaning mechanism and the like. [Figure 5] FIG. 5 is a side view schematically showing the outer edge polishing mechanism and the like. [Figure 6] FIG. 6 is a side view schematically showing a state in which a workpiece is held by the chuck table. [Figure 7] FIG. 7 is a side view schematically showing a state in which the cutting blade is cutting into the workpiece. [Figure 8] FIG. 8 is a side view that schematically shows a state in which the lower surface of the workpiece is being cleaned and the portion to be trimmed is being polished. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a workpiece having a film formed on the first substrate side. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view showing a processing device 2 according to this embodiment. Note that in Fig. 1, some components are expressed as functional blocks. Furthermore, the X-axis (left-right axis), Y-axis (front-back axis), and Z-axis (up-down axis) used in the following description are perpendicular to one another.

[0023] 1, the processing device 2 includes a base 4 that supports various elements that make up the processing device 2. A recessed storage section 4a, whose upper end opens to the upper surface of the base 4, is provided on the front end side of the upper surface of the base 4, and a robot arm 6 that is used to transport a plate-shaped workpiece 11 is housed within the storage section 4a. The robot arm 6 can not only transport the workpiece 11, but also turn the workpiece 11 upside down.

[0024] 2 is a cross-sectional view schematically showing a workpiece 11. The workpiece 11 used in this embodiment is a so-called bonded substrate (bonded wafer) obtained by bonding two substrates (wafers) made of semiconductors such as silicon together. Specifically, the workpiece 11 includes a disk-shaped first substrate (first wafer) 13 with a chamfered outer edge, and a disk-shaped second substrate (second wafer) 15 with a chamfered outer edge.

[0025] First substrate 13 has a circular first surface 13a and a circular second surface 13b opposite first surface 13a. Second substrate 15 has a circular first surface 15a and a circular second surface 15b opposite first surface 15a. The sizes of first substrate 13 and second substrate 15 are generally the same. For example, the disk-shaped workpiece 11 used in this embodiment is formed by bonding the second surface 13b side of first substrate 13 and the first surface 15a side of second substrate 15 together via an optional adhesive layer 17 (see FIG. 4).

[0026] A plurality of devices, typified by integrated circuits (ICs), are provided on each of first substrate 13 and second substrate 15. However, there are no restrictions on the type, number, shape, structure, size, arrangement, etc. of the devices provided on first substrate 13 and second substrate 15. One or both of first substrate 13 and second substrate 15 may not be provided with devices.

[0027] In addition, in this embodiment, a disk-shaped workpiece 11 including two disk-shaped substrates of approximately the same size made of a semiconductor such as silicon is exemplified, but the material, number, shape, structure, size, etc. of the substrates constituting the workpiece 11 are not limited to this embodiment. For example, two or more non-disk-shaped substrates of different sizes made of other semiconductors, ceramics, resin, metal, etc. may also be used for the workpiece 11.

[0028] Furthermore, a protective member, such as a protective tape made of a material such as resin, may be attached to the first surface 13a of the first substrate 13 or the second surface 15b of the second substrate 15 that is exposed in the workpiece 11. By attaching the protective member to the exposed first surface 13a or second surface 15b of the workpiece 11, the workpiece 11 is protected from impacts and the like that may be applied when processing the workpiece 11.

[0029] 1, provided in front of the storage unit 4a are cassette tables 10a and 10b on which cassettes 8 each capable of storing a plurality of workpieces 11 are placed. Also, provided behind the storage unit 4a is a position adjustment mechanism 12 for adjusting the position of the workpiece 11 carried out from the cassette 8.

[0030] The position adjustment mechanism 12 includes a position adjustment table (not shown) having an upper surface that is roughly parallel to the X-axis and Y-axis, and four pins 14 that are arranged around the position adjustment table and can be moved by an actuator (not shown) such as an air cylinder. The workpiece 11 carried out from the cassette 8 by the robot arm 6 is placed on the upper surface of the position adjustment table of the position adjustment mechanism 12.

[0031] For example, by moving the four pins 14 of the position adjustment mechanism 12 in a direction approaching the position adjustment table, the center of the workpiece 11 placed on the upper surface of the position adjustment table is aligned to a predetermined position in a plane roughly parallel to the upper surface. Note that the number of pins 14 constituting the position adjustment mechanism 12 does not necessarily have to be four, and any number of three or more may be used.

[0032] A ball screw type first transport mechanism 16 is provided above the position adjustment mechanism 12. This first transport mechanism 16 includes a ball screw (not shown) connected to a rotary drive source such as a motor, a guide rail 18 that is long along the Y axis, and a moving unit 20 that is attached so as to be able to slide relative to the guide rail 18. When the ball screw is rotated by the rotary drive source, the moving unit 20 moves along the guide rail 18, i.e., along the Y axis.

[0033] The moving unit 20 is provided with an actuator (not shown), such as an air cylinder, that has a movable part that can move along the Z axis. A holding hand 22 that is configured to be able to hold the workpiece 11 is fixed to the movable part of this actuator. Therefore, the holding hand 22 moves along the Z axis together with the movable part by the power of the actuator. The workpiece 11, whose position has been adjusted by the position adjustment mechanism 12, is held by the holding hand 22 and is transported to the rear of the position adjustment mechanism 12 by the first transport mechanism 16.

[0034] A ball screw type chuck table moving mechanism 24 is provided behind the position adjustment mechanism 12. This chuck table moving mechanism 24 includes a ball screw (not shown) connected to a rotary drive source such as a motor, a long guide rail (not shown) along the X-axis, and a moving unit (not shown) attached in a manner that allows it to slide relative to the guide rail. When the ball screw is rotated by the rotary drive source, the moving unit moves along the guide rail, i.e., along the X-axis.

[0035] A chuck table 26 capable of holding the workpiece 11 is disposed above the moving portion of the chuck table moving mechanism 24. Fig. 3 is a perspective view showing the chuck table 26 and other components. Note that in Fig. 3, some of the components are expressed as functional blocks.

[0036] 3, the chuck table 26 has a cylindrical annular support portion 28 made of ceramics or the like. The workpiece 11 transferred from the position adjustment mechanism 12 by the holding hand 22 and the first transfer mechanism 16 is placed on the upper surface 28a of the annular support portion 28 with the first substrate 13 side facing upward.

[0037] An annular groove 28b is provided on the upper surface 28a of the annular support portion 28 along the upper surface 28a. The groove 28b is connected to a suction source (not shown) via a flow path (not shown) or an electromagnetic valve (not shown), and when the electromagnetic valve is opened while the suction source is operating, negative pressure generated by the suction source acts on the groove 28b. This negative pressure sucks the workpiece 11 supported on the upper surface 28a of the annular support portion 28. In other words, the outer edge of the workpiece 11 on the side of the second substrate 15 is held by the upper surface 28a of the chuck table 26.

[0038] A disk-shaped base portion 30 is provided inside the annular support portion 28 and at a position lower than the upper surface 28a. In other words, the position of the upper surface 30a of the base portion 30 (position in the direction along the Z axis) is lower than the position of the upper surface 28a of the annular support portion 28. A recess with a circular opening at the top end is provided in the center of the base portion 30.

[0039] Furthermore, a disk-shaped push-up part 32 that can be moved (raised and lowered) along the Z axis by an actuator (not shown) such as an air cylinder is disposed in the recess of the base part 30. When the push-up part 32 is raised so as to push up the workpiece 11 from below, the workpiece 11 can be easily removed from the chuck table 26.

[0040] The chuck table 26 configured in this manner is supported on a moving portion of the chuck table moving mechanism 24 via a rotation mechanism 34 including a motor and the like, and rotates around the central axis (axis roughly parallel to the Z axis) of the cylindrical annular support portion 28 by the power of the rotation mechanism 34. In other words, the rotation mechanism 34 rotates the chuck table 26 around an axis that intersects with an imaginary plane (plane) including the upper surface 28a of the annular support portion 28.

[0041] 1, a cutting mechanism 36 is disposed above the chuck table 26. The cutting mechanism 36 has a spindle housing 38 that has an internal storage space that is long along the Y axis. The spindle housing 38 is supported by a ball screw type cutting feed mechanism (not shown).

[0042] The cutting feed mechanism includes a ball screw (not shown) connected to a rotary drive source such as a motor, a long guide rail (not shown) along the Z axis, and a moving part (not shown) attached so as to be slidable relative to the guide rail. When the ball screw is rotated by the rotary drive source, the moving part moves along the guide rail, i.e., along the Z axis. The spindle housing 38 is fixed to this moving part and moves along the Z axis together with the moving part.

[0043] A portion of a cylindrical spindle 40 (see FIG. 7), which serves as a rotation axis along the Y axis, is accommodated in the interior storage space of the spindle housing 38. A rotation drive source (not shown), such as a motor, is connected to the base end of the spindle 40, and the spindle 40 rotates around its central axis along the Y axis by the power of this rotation drive source.

[0044] The tip of the spindle 40 is exposed from the spindle housing 38, and an annular cutting blade 42 is attached to the tip of the spindle 40. The cutting blade 42 has a structure in which abrasive grains such as diamond are dispersed in a binder such as vitrified, and is suitable for processing the outer edge of the workpiece 11 (edge trimming).

[0045] Specifically, the cutting blade 42 has a side surface 42a (see FIG. 7) and a side surface 42b (see FIG. 7) that are generally parallel to each other, and an outer peripheral surface 42c (see FIG. 7) that connects the outer edges of the side surfaces 42a and 42b. The distance between the side surfaces 42a and 42b, i.e., the width of the cutting blade 42 (the width of the outer peripheral surface 42c), is typically 1 mm or more and 5 mm or less. However, the width of the cutting blade 42 (the width of the outer peripheral surface 42c) does not necessarily have to be within this range.

[0046] 1, a blade cover 44 capable of partially covering a cutting blade 42 attached to the spindle 40 is provided on the tip side of the spindle housing 38. A pair of cutting nozzles 46 capable of supplying a cutting fluid (cutting fluid) such as water to the cutting blade 42 are arranged below the blade cover 44 so as to sandwich the cutting blade 42 along the Y axis.

[0047] When the outer edge of the workpiece 11 held by the chuck table 26 is machined with the cutting blade 42, for example, a rotary drive source connected to the spindle 40 rotates the cutting blade 42 together with the spindle 40, and the cutting feed mechanism lowers the cutting blade 42 together with the spindle housing 38. In addition, the rotation mechanism 34 rotates the chuck table 26. As a result, the rotating cutting blade 42 cuts into the outer edge of the workpiece 11, and the outer edge of the workpiece 11 is machined (edge trimmed).

[0048] A second transport mechanism 48 is provided on the side of the chuck table moving mechanism 24. The second transport mechanism 48 includes a ball screw (not shown) connected to a rotary drive source such as a motor, a long guide rail (not shown) along the X-axis, and a moving unit 50 attached in a manner that allows it to slide relative to the guide rail. When the ball screw is rotated by the rotary drive source, the moving unit 50 moves along the guide rail, i.e., along the X-axis.

[0049] The base end of the arm unit 52 is connected to the moving unit 50 via an actuator (not shown) such as an air cylinder and a rotary drive source (not shown) such as a motor. The arm unit 52 moves (lifts and lowers) along the Z axis by the power of this actuator. The arm unit 52 also rotates around an axis roughly parallel to the Z axis by the power of the rotary drive source.

[0050] That is, the tip of the arm unit 52 rotates around the base end of the arm unit 52 in a plane generally perpendicular to the Z axis. The range (angle) within which the arm unit 52 can rotate is typically 90° or more. A holding hand 54 configured to be able to hold the workpiece 11 is fixed to the tip of the arm unit 52. After being machined by the cutting mechanism 36, the workpiece 11 on the chuck table 26 is held by the holding hand 54 and transported by the second transport mechanism 48.

[0051] A lower surface cleaning mechanism 56 is provided on the path of transport of the workpiece 11 by the second transport mechanism 48. FIG. 4 is a perspective view that schematically shows the lower surface cleaning mechanism 56 and the like. As shown in FIG. 4, the lower surface cleaning mechanism 56 has, for example, four holding parts 58 configured to be able to hold the outer edge of the workpiece 11 from below. The four holding parts 58 are arranged at approximately equal intervals (equidistant angular intervals) so as to surround a recessed accommodation part 4b that has a circular opening on the upper surface of the base 4. Note that the number of holding parts 58 that make up the lower surface cleaning mechanism 56 does not necessarily have to be four, and may be any number of three or more.

[0052] Each holder 58 includes, for example, a disk-shaped first support portion 58a and a second support portion 58b that protrudes upward from the center of the first support portion 58a, and the workpiece 11 transported by the second transport mechanism 48 is placed on the upper surface of the first support portion 58a with the first substrate 13 side facing upward. Note that only the outer edge of the second surface 15b of the second substrate 15 contacts the upper surface of this first support portion 58a, and other parts of the workpiece 11 do not contact it.

[0053] The second support portion 58b is formed in a cylindrical shape with a smaller diameter than the first support portion 58a. The outer edge of the workpiece 11 placed on the upper surface of the first support portion 58a comes into contact with the side surface of this second support portion 58b. In this manner, the holder 58 is configured to hold the workpiece 11 only by its outer edge. Therefore, when the workpiece 11 is held by the holder 58, the portion of the workpiece 11 excluding the outer edge, for example, the second substrate 15 side (lower surface side) of the workpiece 11, is exposed.

[0054] Each holder 58 is connected to a rotary drive source (not shown), such as a motor, and is rotated by the power of this rotary drive source around the central axis of the second support portion 58b, i.e., around an axis generally parallel to the Z axis. When the holder 58 holding the workpiece 11 is rotated, the workpiece 11 also rotates around an axis generally parallel to the Z axis.

[0055] In the accommodation section 4b, a cylindrical lower surface cleaning tool (cleaning section) 60 that is long in a direction roughly perpendicular to the Z axis is arranged in a manner that allows it to come into contact from below with the workpiece 11 held by the holding section 58. In other words, this lower surface cleaning tool 60 comes into contact from below with the exposed second substrate 15 side of the workpiece 11. The lower surface cleaning tool 60 is configured in a brush shape using fibers made of resin such as polyamide, and is suitable for cleaning the second substrate 15 side (lower surface side) of the workpiece 11.

[0056] A rotary drive source (not shown), such as a motor, is connected to an end of the lower-surface cleaning tool 60. The power of this rotary drive source causes the lower-surface cleaning tool 60 to rotate around the central axis of the lower-surface cleaning tool 60, that is, around an axis roughly perpendicular to the Z axis. In addition, a lower-surface cleaning nozzle (cleaning unit) 62 that can spray a cleaning liquid (cleaning liquid), such as water, upward is disposed adjacent to the lower-surface cleaning tool 60 in the storage unit 4b.

[0057] An outer edge polishing mechanism (polishing unit) 64 is disposed on the side of the holding unit 58 for polishing the outer edge of the workpiece 11 after it has been machined by the cutting mechanism 36. FIG. 5 is a side view schematically showing the outer edge polishing mechanism 64 and other components. Note that in FIG. 5, some of the components are expressed as functional blocks. As shown in FIG. 5, the outer edge polishing mechanism 64 includes an arm unit 66 that is long in a direction substantially perpendicular to the Z axis.

[0058] A rotary drive source 68 such as a motor having a rotary shaft aligned along the Z axis is provided above the distal end of the arm unit 66. The distal end of the rotary shaft of the rotary drive source 68 is located, for example, below the arm unit 66, and a disc-shaped (cylindrical) polishing pad 70 having an outer circumferential surface 70a and a bottom surface 70b is attached to the distal end of this rotary shaft. The polishing pad 70 is made of, for example, nonwoven fabric or polymer foam, and does not contain abrasive grains. However, the polishing pad 70 may contain abrasive grains.

[0059] A moving mechanism 72 is connected to the base end of the arm unit 66. This moving mechanism 72 includes two sets of actuators, such as air cylinders, and moves the arm unit 66 in a direction generally parallel to the Z axis and a direction generally perpendicular to the Z axis. Specifically, the moving mechanism 72 can move the arm unit 66 between a polishing position where the polishing pad 70 contacts the outer edge of the workpiece 11 and a retracted position where the polishing pad 70 is sufficiently separated from the workpiece 11.

[0060] The moving mechanism 72 may include a ball screw type actuator like the first transport mechanism 16, instead of or in addition to an actuator like an air cylinder.

[0061] With the arm 66 positioned at the retracted position, the polishing pad 70 is immersed in a polishing liquid (polishing solution) stored in, for example, a container (not shown). This allows a polishing liquid suitable for polishing the workpiece 11 to be supplied from the outside to the polishing pad 70. When the workpiece 11 is mainly made of silicon, for example, a slurry in which silica-based abrasive grains are dispersed in an aqueous solution of an alkali such as sodium hydroxide is used as the polishing liquid.

[0062] The polishing liquid may be supplied to the polishing pad 70 by other methods. For example, the outer edge polishing mechanism 64 may be provided with a supply path for supplying the polishing liquid to the polishing pad 70. Furthermore, if the polishing pad 70 itself already holds a sufficient amount of polishing liquid, the polishing liquid does not need to be supplied to the polishing pad 70 from outside.

[0063] When polishing the outer edge of the workpiece 11, for example, a rotary drive source connected to the holder 58 rotates the workpiece 11 together with the holder 58. Then, the moving mechanism 72 moves the arm 66 from the retracted position to the polishing position, and the rotary drive source 68 rotates the polishing pad 70. As a result, the outer peripheral surface 70a and bottom surface 70b of the polishing pad 70, which is also rotating, come into contact with the outer peripheral portion of the rotating workpiece 11, and the outer peripheral portion of the workpiece 11 is polished.

[0064] 1, a third transport mechanism 74 is provided to the side of the lower surface cleaning mechanism 56 and the outer edge polishing mechanism 64. The third transport mechanism 74 includes a ball screw (not shown) connected to a rotary drive source such as a motor, a guide rail (not shown) that is long along the Y axis, and a moving unit 76 that is attached in a manner that allows it to slide relative to the guide rail. When the ball screw is rotated by the rotary drive source, the moving unit 76 moves along the guide rail, i.e., along the Y axis.

[0065] The base end of an arm unit 78 is connected to the moving unit 76 via an actuator (not shown), such as an air cylinder. The arm unit 78 moves (lifts and lowers) along the Z axis by the power of this actuator. A holding hand 80 configured to be able to hold the workpiece 11 is fixed to the tip of the arm unit 52. After the second substrate 15 side of the workpiece 11 has been cleaned by the lower surface cleaning mechanism 56 and the outer edge polished by the outer edge polishing mechanism 64, the workpiece 11 is held by the holding hand 80 and transported forward by the third transport mechanism 74.

[0066] An upper surface cleaning mechanism 82 is provided in front of the lower surface cleaning mechanism 56 and the outer edge polishing mechanism 64. The upper surface cleaning mechanism 82 includes a spinner table 84 that can hold the workpiece 11. The spinner table 84 is supported on the base 4 via a rotation mechanism (not shown) including a motor or the like, and rotates around an axis roughly parallel to the Z axis by the power of this rotation mechanism. The workpiece 11 transported by the third transport mechanism 74 is placed on the upper surface of the spinner table 84 with the first substrate 13 side facing upward.

[0067] An upper surface cleaning nozzle 86 capable of spraying a cleaning liquid (cleaning liquid) such as water downward is disposed above the spinner table 84. Also disposed above the spinner table 84 is an upper surface cleaning tool 88 capable of contacting the first substrate 13 side (upper surface side) of the workpiece 11 held by the spinner table 84 and cleaning this first substrate 13 side.

[0068] The upper surface cleaning tool 88 is a sponge-like member formed into a disk shape from a resin such as PVA (polyvinyl alcohol), and has high flexibility and water absorption. The upper surface cleaning tool 88 is connected via an arm to an actuator (not shown) such as an air cylinder and a rotation drive source (not shown) such as a motor.

[0069] Therefore, the upper surface cleaning tool 88 can move (lift) along the Z axis by the power of this actuator, and rotate (pivot) around an axis roughly parallel to the Z axis by the power of the rotation drive source, thereby cleaning the second substrate 15 side of the workpiece 11. The workpiece 11 cleaned by the upper surface cleaning mechanism 82 is then carried into the cassette 8 by the robot arm 6.

[0070] A controller (control unit) 90 is connected to each element of the processing device 2. This controller 90 is configured by a computer including, for example, a processing device 90a and a storage device 90b, and controls the operation of each element of the processing device 2 described above so that the workpiece 11 is processed appropriately.

[0071] The processing device 90a is typically a CPU (Central Processing Unit) and performs various processes necessary to control the above-mentioned elements. The storage device 90b includes, for example, a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a hard disk drive or flash memory. The functions of the controller 90 are realized, for example, by the processing device 90a operating in accordance with a program stored in the storage device 90b.

[0072] An input / output device 92 serving as a user interface is connected to this controller 90. The input / output device 92 is, for example, a touch screen, and inputs commands from an operator to the controller 90. Furthermore, the input / output device 92 outputs (displays, in the case of a touch screen) information related to the processing device 2 based on commands from the controller 90 in a format that can be recognized by the operator.

[0073] In this embodiment, an input / output device 92 having both an input function and an output function is shown, but an input device having an input function and an output device having an output function may each be connected to the controller 90. As the input device, for example, a keyboard, a mouse, etc. may be used. As the output device, for example, a display device such as a liquid crystal display, a speaker that can transmit information by voice, an indicator light that can transmit information by the color of light or the state of light emission (on, blinking, off, etc.), etc. may be used.

[0074] Next, a method for processing a workpiece using the above-described processing apparatus 2 will be described. In the method for processing a workpiece according to this embodiment, first, the second substrate 15 side of the above-described workpiece 11 is held by the upper surface 28a of the chuck table 26 (holding step). Fig. 6 is a side view schematically showing the state in which the workpiece 11 is held by the chuck table 26. For ease of explanation, Fig. 6 shows a cross section of the workpiece 11.

[0075] Specifically, the position of the workpiece 11 carried out from the cassette 8 is adjusted by, for example, the position adjustment mechanism 12, and then the workpiece 11 is placed on the chuck table 26 with the second substrate 15 side facing downward, as shown in Fig. 6. Thereafter, when the solenoid valve is opened to apply negative pressure generated by the suction source to the groove 28b, the workpiece 11 is sucked and held by the chuck table 26.

[0076] After the second substrate 15 side of the workpiece 11 is held by the upper surface 28a of the chuck table 26, the outer edge of the workpiece 11 is machined (edge trimmed) by the cutting blade 42 (trim step). Figure 7 is a side view that schematically shows the cutting blade 42 cutting into the workpiece 11. For ease of explanation, a cross section of the workpiece 11 is also shown in Figure 7.

[0077] Specifically, first, the chuck table moving mechanism 24 moves the chuck table 26 so that the outer edge of the workpiece 11 is positioned directly below the cutting blade 42. Next, the cutting mechanism 36 rotates the annular cutting blade 42, which has side surfaces 42a and 42b and an outer peripheral surface 42c. Then, in this state, the cutting feed mechanism lowers the cutting blade 42 together with the spindle housing 38.

[0078] As a result, the rotating cutting blade 42 cuts into the workpiece 11 from the first substrate 13 side. For example, when the amount of descent of the cutting blade 42 reaches a desired cutting feed amount, the cutting feed mechanism stops the descent of the cutting blade 42. Thereafter, as shown in FIG. 7, the rotation mechanism 34 rotates the workpiece 11 together with the chuck table 26. The amount of rotation of the workpiece 11 by the rotation mechanism 34 is one rotation (one revolution) or more.

[0079] By this operation, the rotating cutting blade 42 cuts into the workpiece 11 along the outer edge of the workpiece 11 from the first substrate 13 side, processing the outer edge portion of the workpiece 11. Then, a trimmed portion 19 is formed along the outer edge of the workpiece 11, the trimmed portion having a side surface 19a that is in contact with one side surface 42a of the cutting blade 42 and a bottom surface 19b that is in contact with the outer peripheral surface 42c of the cutting blade 42.

[0080] When the first substrate 13 constituting the workpiece 11 is thick, the above-described operation is repeated. Specifically, the lowering of the cutting blade 42 and the rotation of the workpiece 11 are alternately repeated until the lower end of the cutting blade 42 reaches the second substrate 15. In other words, the cutting blade 42 cuts from the first substrate 13 side to a depth that reaches the second substrate 15.

[0081] In this embodiment, the lowering of the cutting blade 42 and the rotation of the workpiece 11 are performed at different times, but they may also be performed at the same time. That is, the cutting feed mechanism may lower the rotating cutting blade 42 together with the spindle housing 38 while the rotation mechanism 34 rotates the workpiece 11 together with the chuck table 26. In this case, too, the lowering of the cutting blade 42 by the cutting feed mechanism continues until the lower end of the cutting blade 42 reaches the second substrate 15.

[0082] In this embodiment, the height of the side surface 19a of the trimmed portion 19 (the length along the thickness direction of the workpiece 11) is, for example, about 0.01 mm to 1.0 mm. Also, the width of the bottom surface 19b of the trimmed portion 19 (the length along the radial direction of the workpiece 11) is, for example, about 0.1 mm to 10 mm. However, the height of the side surface 19a and the width of the bottom surface 19b of the trimmed portion 19 do not necessarily have to be within these ranges.

[0083] After the outer edge of the workpiece 11 is machined by the cutting blade 42 to form the trimmed portion 19, for example, the second substrate 15 side of the workpiece 11 is cleaned (cleaning step). Furthermore, in this embodiment, when the second substrate 15 side of the workpiece 11 is cleaned, the side surface 19a and bottom surface 19b of the trimmed portion 19 are polished by the polishing pad 70 (polishing step).

[0084] 8 is a side view that schematically shows a state in which the underside (second substrate 15 side) of workpiece 11 is cleaned and the portion to be trimmed 19 is polished. Note that for ease of explanation, a cross section of workpiece 11 is also shown in FIG. 8. Specifically, first, processed workpiece 11 is carried out from chuck table 26 and placed on multiple holders 58 with the second substrate 15 side facing downward.

[0085] As described above, each holder 58 is configured to be able to hold only the outer edge of the workpiece 11. Therefore, when the workpiece 11 is held by each holder 58, the second substrate 15 side (lower surface side) of the workpiece 11 is exposed, and the lower surface cleaning tool 60 comes into contact with this exposed second substrate 15 side of the workpiece 11.

[0086] After the workpiece 11 is held by the holder 58, as shown in Fig. 8, a rotary drive source connected to the holder 58 rotates the holder 58, thereby rotating the workpiece 11. Furthermore, a cleaning liquid is supplied from a lower surface cleaning nozzle 62 (Fig. 4) to the second substrate 15 side of the workpiece 11, and a rotary drive source connected to the lower surface cleaning tool 60 rotates the lower surface cleaning tool 60. As a result, the second substrate 15 side of the workpiece 11 is cleaned.

[0087] Furthermore, as described above, at the timing when the second substrate 15 side of the workpiece 11 is being cleaned, that is, at the timing when the workpiece 11 is rotating, the moving mechanism 72 moves the arm portion 66 from the retracted position to the polishing position, and the rotation drive source 68 rotates the polishing pad 70. As a result, the outer peripheral surface 70a and the bottom surface 70b of the rotating polishing pad 70 are pressed against the side surface 19a and the bottom surface 19b of the portion to be trimmed 19, respectively, and the portion to be trimmed 19 is polished.

[0088] 8, the height of the outer peripheral surface 70a of the polishing pad 70 (the length in the vertical direction, the thickness of the polishing pad 70) is greater than the height of the side surface 19a of the portion to be trimmed 19 (the length along the thickness direction of the workpiece 11). In addition, the diameter of the bottom surface 70b of the polishing pad 70 (the length in the horizontal direction, the width of the polishing pad 70) is greater than the width of the bottom surface 19b of the portion to be trimmed 19 (the length along the radial direction of the workpiece 11).

[0089] Therefore, while the workpiece 11 is rotating, when the polishing pad 70 is pressed against the trimmed portion 19 so that the connection portion between the outer peripheral surface 70a and the bottom surface 70b of the polishing pad 70 comes into contact with the connection portion between the side surface 19a and the bottom surface 19b of the trimmed portion 19, the entire side surface 19a and the bottom surface 19b of the trimmed portion 19 are polished by the polishing pad 70.

[0090] Although there are no specific limitations on the height of the outer peripheral surface 70a of the polishing pad 70, it is preferable that the height of the outer peripheral surface 70a of the polishing pad 70 be 0.01 mm or more greater than the height of the side surface 19a of the trimmed portion 19 so that the entire side surface 19a of the trimmed portion 19 can be reliably polished by the outer peripheral surface 70a of the polishing pad 70. Typically, the height of the outer peripheral surface 70a of the polishing pad 70, i.e., the thickness of the polishing pad 70, is about 0.1 mm to 5.0 mm.

[0091] Similarly, there are no specific limitations on the diameter of the bottom surface 70b of the polishing pad 70, but it is preferable that the diameter of the bottom surface 70b of the polishing pad 70 be 0.01 mm or more larger than the width of the bottom surface 19b of the trimmed portion 19 so that the entire bottom surface 19b of the trimmed portion 19 can be reliably polished by the bottom surface 70b of the polishing pad 70. Typically, the diameter of the bottom surface 70b of the polishing pad 70, i.e., the width of the polishing pad 70, is about 10 mm to 30 mm.

[0092] Furthermore, in this embodiment, the rotating disc-shaped (cylindrical) polishing pad 70 is pressed against the trimmed portion 19 of the rotating workpiece 11, so that the entire trimmed portion 19 is polished efficiently. The rotational speed (rotational speed) of the polishing pad 70 is, for example, 500 rpm or more and 1500 rpm or less, preferably 800 rpm or more and 1000 rpm or less. The rotational speed (rotational speed) of the workpiece 11 is, for example, 50 rpm or more and 150 rpm or less, preferably 80 rpm or more and 100 rpm or less. However, the rotational speed of the polishing pad 70 and the rotational speed of the workpiece 11 do not necessarily have to be within these ranges.

[0093] When the side surface 19a and bottom surface 19b of the portion to be trimmed 19 become smooth, polishing of the side surface 19a and bottom surface 19b is complete, and when the second substrate 15 side of the workpiece 11 becomes clean, cleaning of the second substrate 15 side of the workpiece 11 is complete. Note that in order to sufficiently prevent foreign matter from adhering to the side surface 19a and bottom surface 19b of the portion to be trimmed 19 and film peeling from the bottom surface 19b of the portion to be trimmed 19, the side surface 19a and bottom surface 19b of the portion to be trimmed 19 are polished, for example, until the arithmetic mean roughness (Ra) specified in JIS B 0601 is 1.0 μm or less, and preferably 0.5 μm or less.

[0094] When cleaning of the second substrate 15 side of the workpiece 11 and polishing of the trimmed portion 19 are completed, the workpiece 11 is removed from the holder 58 and is loaded, for example, into the spinner table 84 of the upper surface cleaning mechanism 82. Thereafter, the workpiece 11, whose upper surface side (first substrate 13 side) has been cleaned by the upper surface cleaning mechanism 82, is removed from the spinner table 84 by, for example, the robot arm 6 and loaded into the cassette 8.

[0095] As described above, according to the workpiece processing method and processing device 2 of this embodiment, the side surface 19a and bottom surface 19b of the trimmed portion 19 formed on the workpiece 11 are polished by the polishing pad 70, so that the side surface 19a and bottom surface 19b of the trimmed portion 19 become smoother than when they are not polished by the polishing pad 70.

[0096] This makes it less likely for foreign matter to adhere to trimmed portion 19 and for a film to peel off from trimmed portion 19 than when side surface 19a and bottom surface 19b of trimmed portion 19 are not polished. Therefore, according to the workpiece processing method and processing device 2 of this embodiment, it is possible to reduce the possibility of foreign matter adhering to trimmed portion 19 and a film peeling off from trimmed portion 19.

[0097] The present invention is not limited to the above-described embodiments and can be practiced with various modifications. For example, after the side surface 19a and bottom surface 19b of the trimmed portion 19 are polished by the workpiece processing method according to the above-described embodiments, an arbitrary film may be formed on the first substrate 13 side of the workpiece 11 (first surface 13a of first substrate 13 and bottom surface 19b of the trimmed portion 19) (film formation step).

[0098] That is, the workpiece processing method according to the present invention may further include, after the step of polishing the side surface 19a and bottom surface 19b of the trimmed portion 19 (polishing step), a step of forming a film on the bottom surface 19b of the trimmed portion 19 (film formation step). Figure 9 is a cross-sectional view schematically showing the workpiece 11 on which the film 21 is formed on the first substrate 13 side.

[0099] 9, the film 21 formed on the first substrate 13 side of the workpiece 11 is typically a conductive film, a semiconductor film, or an insulator film, and includes a film 21a in close contact with the first surface 13a of the first substrate 13 and a film 21b in close contact with the bottom surface 19b of the portion to be trimmed 19. Examples of methods for forming the film 21 include CVD (Chemical Vapor Deposition) and PVD (Physical Vapor Deposition).

[0100] However, the material of film 21, the method of forming film 21, the position where film 21 is formed, etc. are not limited to these. For example, film 21 may be formed on side surface 19a of trimmed portion 19. In other words, film 21 may include a portion that is in close contact with side surface 19a of trimmed portion 19.

[0101] In the workpiece processing method according to the present invention, the bottom surface 19b (and side surface 19a) of the portion to be trimmed 19 is polished and smoothed by the polishing pad 70, so the film 21b formed on the bottom surface 19b (and the film formed on the side surface 19a) is less likely to peel off from the bottom surface 19b (and side surface 19a). This reduces device defects caused by the film 21b peeling off from the bottom surface 19b (and side surface 19a).

[0102] Furthermore, in the above-described embodiment, the side surface 19a and bottom surface 19b of the trimmed portion 19 are polished when the second substrate 15 side of the workpiece 11 is cleaned, but cleaning the second substrate 15 side of the workpiece 11 and polishing the side surface 19a and bottom surface 19b of the trimmed portion 19 may be performed at different times.

[0103] In this case, when polishing the side surface 19a and bottom surface 19b of the trimmed portion 19, the workpiece 11 does not necessarily have to be held in a manner that exposes the second substrate 15. For example, the side surface 19a and bottom surface 19b of the trimmed portion 19 can be polished with the second substrate 15 side of the workpiece 11 held by the chuck table 26.

[0104] Furthermore, in the above-described embodiment, a disk-shaped (cylindrical) polishing pad 70 is used to polish the side surface 19a and bottom surface 19b of the trimmed portion 19, but the trimmed portion 19 may also be polished with a non-disk-shaped polishing pad, for example, a rectangular parallelepiped polishing pad. In this case, the height of the side surface of the polishing pad is greater than the height of the side surface 19a of the trimmed portion 19, and the width of the polishing pad is greater than the width of the bottom surface 19b of the trimmed portion 19.

[0105] In addition, the structures, methods, etc. according to the above-described embodiments and modifications may be modified and implemented without departing from the scope of the present invention. [Explanation of symbols]

[0106] 11: Workpiece 13: First substrate (first wafer) 13a: 1st page 13b: 2nd side 15: Second substrate (second wafer) 15a: 1st page 15b: 2nd side 17: Adhesive layer 19: Trimmed part 19a: Side 19b: bottom 21: Membrane 21a: Membrane 21b: Membrane 2: Processing equipment 4: Base 4a: Storage section 4b: Storage section 6: Robot arm 8: Cassette 10a: Cassette table 10b: Cassette table 12:Position adjustment mechanism 14: Pin 16: First transport mechanism 18: Guide rail 20: Moving part 22: Holding hand 24: Chuck table movement mechanism 26: Chuck table 28: Annular support part 28a:Top surface 28b: Groove 30: Base part 30a:Top surface 32: Push-up part 34: Rotation mechanism 36: Cutting mechanism 38: Spindle housing 40: Spindle 42: Cutting blade 42a: Side 42b: Side 42c: Outer surface 44: Blade cover 46: Cutting nozzle 48: Second transport mechanism 50: Moving part 52: Arm part 54: Holding Hand 56: Underside cleaning mechanism 58: Holding part 58a: 1st support part 58b: Second support part 60: Underside cleaning equipment (cleaning part) 62: Underside cleaning nozzle (cleaning part) 64: Outer edge polishing mechanism (polishing section) 66: Arm part 68: Rotation drive source 70: Polishing pad 70a: Outer surface 70b: Bottom 72: Movement mechanism 74: Third transport mechanism 76: Moving part 78: Arm section 80: Holding Hand 82: Top cleaning mechanism 84: Spinner table 86: Top cleaning nozzle 88: Top cleaning tool 90: Controller (control unit) 90a: Processing device 90b: Storage device 92: Input / output device

Claims

1. a holding step of holding a second substrate side of a workpiece having a structure in which a first substrate and a second substrate are bonded together on an upper surface of a chuck table; a trimming step in which, after the holding step, an annular cutting blade having an outer peripheral surface and a side surface is rotated while cutting the cutting blade along the outer edge of the workpiece to a depth reaching the second substrate from the first substrate side, thereby forming a trimmed portion along the outer edge of the workpiece, the trimmed portion having a bottom surface contacted by the outer peripheral surface of the cutting blade and a side surface contacted by the side surface of the cutting blade; a polishing step of polishing the bottom surface and the side surface of the trimmed portion with a polishing pad.

2. 2. The method for processing a workpiece according to claim 1, wherein, in the polishing step, the disc-shaped polishing pad having an outer peripheral surface and a bottom surface is rotated while the bottom surface of the polishing pad is brought into contact with the bottom surface of the trimmed portion and the outer peripheral surface of the polishing pad is brought into contact with the side surface of the trimmed portion.

3. the height of the outer peripheral surface of the polishing pad is greater than the height of the side surface of the trimmed portion; the diameter of the bottom surface of the polishing pad is greater than the width of the bottom surface of the trimmed portion; The method for processing a workpiece according to claim 2 , wherein the polishing step includes pressing the polishing pad against the bottom surface and the side surface of the portion to be trimmed.

4. after the trimming step, further comprising a cleaning step of cleaning the second substrate side of the workpiece while holding the workpiece so that the second substrate side is exposed; 4. The method for processing a workpiece according to claim 1, wherein the polishing step is carried out when the cleaning step is carried out.

5. 4. The method for processing a workpiece according to claim 1, further comprising a film forming step of forming a film on the bottom surface of the trimmed portion after the polishing step.

6. a chuck table having an upper surface capable of holding the second substrate side of a workpiece having a structure in which a second substrate is bonded to a first substrate; a rotation mechanism that rotates the chuck table around an axis that intersects with a plane that includes the upper surface; a cutting mechanism having a rotating shaft to which an annular cutting blade having an outer circumferential surface and a side surface is attached; a polishing unit on which a polishing pad is attached for polishing the bottom surface and the side surface of a trimmed portion formed along the outer edge of the workpiece by the cutting mechanism and having a bottom surface in contact with the outer peripheral surface of the cutting blade and a side surface in contact with the side surface of the cutting blade.

7. the polishing unit has a rotation shaft on which the disc-shaped polishing pad having an outer circumferential surface and a bottom surface is mounted, The processing device according to claim 6 , wherein the polishing pad is rotated while the bottom surface of the polishing pad is brought into contact with the bottom surface of the portion to be trimmed and the outer circumferential surface of the polishing pad is brought into contact with the side surface of the portion to be trimmed.

8. a moving mechanism that moves the polishing unit so as to press the polishing pad against the bottom surface and the side surface of the portion to be trimmed; the height of the outer peripheral surface of the polishing pad is greater than the height of the side surface of the trimmed portion; The processing device according to claim 7 , wherein the diameter of the bottom surface of the polishing pad is larger than the width of the bottom surface of the portion to be trimmed.

9. a holder that holds the workpiece so that the second substrate side is exposed; The processing apparatus according to claim 6 , further comprising: a cleaning unit that cleans the second substrate side of the workpiece.

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