JP7300943B2 - Foreign matter detection method on holding surface - Google Patents

Description

The present invention relates to a foreign matter detection method for a holding surface of a holding table.

There is known a technique for cutting a workpiece containing a tough material such as resin, metal, tape, etc., with a cutting tool having a diamond tip to make the height uniform (see, for example, Patent Document 1).

JP-A-2000-173954 JP 2005-197578 A

However, if foreign matter is present on the holding surface of the holding table of the cutting tool, the thickness of the workpiece at that portion becomes thin, and there is a problem that the workpiece cannot be cut flat. Therefore, as a technique for detecting whether or not a foreign object exists on a holding table, a technique for reading interference fringes on the surface of a workpiece on which a mirror surface is formed has been proposed (see, for example, Patent Document 2). . However, in order to read the interference fringes on the surface with visible light, there is a problem that a special measuring instrument such as a laser interferometer is required, which is difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a method for detecting foreign matter on the holding surface of the holding table, which can more easily detect foreign matter on the holding surface of the holding table.

In order to solve the above problems and achieve the object, a method for detecting foreign matter on a holding surface according to the present invention includes: a holding table for holding a workpiece on a holding surface; and a cutting unit for cutting a workpiece held on the holding table by a wheel. a holding step of holding the back side of the workpiece coated with resin on a holding table; and cutting the workpiece from the front side of the workpiece to a thickness at which the resin is not completely removed by the cutting unit. a processing step, a determination step of determining whether the state of interference fringes formed in the resin after the processing step exceeds a predetermined allowable range, and, if the allowable range is exceeded, the holding table. and a cleaning step of cleaning the holding surface.

Further, in order to solve the above problems and achieve the object, a method for detecting a foreign matter on a holding surface according to the present invention includes a holding table for holding a workpiece on the holding surface and a grinding wheel attached to the tip of a spindle. a grinding unit for grinding a workpiece held on the holding table, a method for detecting foreign matter on a holding surface of a grinding apparatus comprising: a resin coating step of coating the surface of the workpiece with a resin; a holding step of holding the back side of the workpiece coated with the resin on a holding table; and a grinding step of grinding the workpiece from the front side of the workpiece to a thickness at which the resin is not completely removed by the grinding unit. a determination step of determining whether or not the state of the interference fringes formed in the resin after the processing step exceeds a predetermined allowable range; and a cleaning step of cleaning.

After performing the processing step and before performing the determining step, the method further comprises a step of removing the workpiece from the holding table and transferring the thickness irregularities caused by the foreign matter to the surface side of the workpiece. good too.

The cleaning step may include an organic solvent supplying step of supplying an organic solvent to the holding surface, and a foreign matter removing step of cleaning foreign matter floating up from the holding surface with the organic solvent.

According to the method for detecting foreign matter on the holding surface of the present invention, foreign matter on the holding surface of the holding table can be detected more easily.

FIG. 1 is a perspective view showing the outline of the configuration of a cutting tool that implements the method for detecting foreign matter on a holding surface according to Embodiment 1. FIG. FIG. 2 is a perspective view showing an outline of the configuration of a holding table in the cutting tool of FIG. 1. FIG. FIG. 3 is a cross-sectional view taken along line III-III of FIG. FIG. 4 is a flow chart showing the processing of the foreign matter detection method for the holding surface according to the first embodiment. 5 is a cross-sectional view showing the resin coating step of FIG. 4. FIG. 6 is a cross-sectional view showing the holding step and processing step of FIG. 4. FIG. 7 is a top view schematically showing interference fringes formed through the processing steps of FIG. 4. FIG. FIG. 8 is a flow chart showing detailed processing of the cleaning step of FIG. 9 is a cross-sectional view showing the organic solvent supplying step of FIG. 8. FIG. FIG. 10 is a cross-sectional view showing the foreign matter removing step of FIG. 11A and 11B are cross-sectional views showing holding steps and processing steps in a method for detecting a foreign object on a holding surface according to the second embodiment.

A form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions, or changes in configuration can be made without departing from the gist of the present invention.

[Embodiment 1]
A foreign matter detection method on a holding surface according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a cutting tool 1 that implements a foreign matter detection method on a holding surface according to Embodiment 1. As shown in FIG. FIG. 2 is a perspective view showing the outline of the configuration of the holding table 10 in the cutting tool 1 of FIG. 1. As shown in FIG. FIG. 3 is a cross-sectional view taken along line III-III of FIG. The foreign matter detection method on the holding surface according to the first embodiment of the present invention is a method implemented in the cutting tool 1 shown in FIG. It is a method to confirm whether

As shown in FIG. 1, the tool cutting device 1 that implements the foreign matter detection method on the holding surface according to the first embodiment includes a holding table 10, a cutting unit 20, a processing feed unit 30, a cutting feed unit 40, and a control unit. a unit 50; The cutting tool 1 actually turns and cuts a workpiece in which a plurality of devices having bumps provided on a substrate of silicon or the like is formed and the devices are sealed with a mold resin. It is something to do.

The holding table 10 has a holding surface 11 for holding a workpiece, and is rotatable around an axis in the Z-axis direction. The holding table 10 is formed in a disc shape from a metal material such as stainless steel. In the first embodiment, the holding surface 11 has a circular shape and is provided substantially parallel to the horizontal XY plane.

As shown in FIG. 1, the holding table 10 is provided on the upper surface of the apparatus main body 2 so as to be movable in the X-axis direction by the processing feed unit 30 . The holding table 10 is movable in the X-axis direction between a loading/unloading position for loading/unloading the workpiece and a machining position for cutting the workpiece held by the holding surface 11 by the cutting unit 20. is provided in

As shown in FIGS. 2 and 3, the holding table 10 includes an outer peripheral annular holding portion 12 formed on the outer peripheral portion, a suction recess 13 formed inside the outer peripheral annular holding portion 12, and a suction recess 13 provided in the suction recess 13. and a plurality of support pins 14 mounted on the support pins 14 . In the holding table 10 , the upper surface of the outer peripheral annular holding portion 12 and the upper surfaces of the plurality of support pins 14 constitute the holding surface 11 .

In the first embodiment, the holding table 10 is formed in a cylindrical shape with an outer peripheral annular holding portion 12 having a width of approximately 1 mm and a support pin 14 having a diameter of 1 mm. Further, in the holding table 10, as shown in FIG. 3, the holding table 10 has a thickness of 200 μm formed on the upper surfaces of the outer peripheral annular holding portion 12 and the plurality of support pins 14 and the holding surface 11 for holding the workpiece. It is composed of a plated layer made of nickel or the like. Note that the holding table 10 is not limited to this in the present invention, and may have any form as long as it can hold the workpiece on the holding surface 11 .

In the holding table 10 , the suction recess 13 communicates with suction means (not shown) through a suction passage 15 . By operating a suction means (not shown), the holding table 10 applies a negative pressure to the suction concave portion 13 through the suction passage 15 and sucks and holds the workpiece placed on the holding surface 11 . At this time, the workpiece is supported by the outer peripheral annular holding portion 12 and the plurality of support pins 14 . The holding table 10 is supported by a support base (not shown) that is rotatable around an axis parallel to the vertical Z-axis direction.

The cutting unit 20 includes a spindle 21, a bite wheel 23 including a bite tool 22, and a motor 24, as shown in FIG. The axial direction of the spindle 21 is arranged along the vertical direction, which is the direction orthogonal to the holding surface 11 . The bite wheel 23 is attached to the distal end of the spindle 21 on the vertical upper side with the bite tool 22 directed downward in the vertical direction. The motor 24 is provided on the spindle 21 and rotates the spindle 21 around its axis. The cutting unit 20 turns and cuts the workpiece held on the holding table 10 by rotating a cutting tool wheel 23 including a cutting tool 22 attached to the tip of the spindle 21 with a motor 24 . The cutting surface of the cutting unit 20 and the surface of the workpiece being cut by the cutting unit 20 are parallel to the holding surface 11, that is, substantially parallel to the horizontal XY plane.

As shown in FIG. 1, the processing feed unit 30 is installed on the apparatus main body 2 and relatively moves the holding table 10 in the X-axis direction, which is the processing feed direction parallel to the holding surface 11 . The processing feed unit 30 moves the holding table 10 between the loading/unloading position and the processing position by moving the support base supporting the holding table 10 in the X-axis direction.

As shown in FIG. 1, the incision feeding unit 40 is arranged on the upright wall 3 erected at the +X direction end of the upper surface of the apparatus main body 2 . The cutting feed unit 40 is a cutting unit mounted via a moving base by a screw rod provided along the Z-axis direction, which is a direction orthogonal to the holding surface 11 of the holding table 10, and a pulse motor that rotationally drives the screw rod. 20 is moved along the Z-axis direction. The cutting feed unit 40 moves the cutting unit 20 along the −Z direction, which is the downward vertical direction, and moves the cutting tool 22 toward the workpiece sucked and held on the holding surface 11 of the holding table 10 .

The control unit 50 controls each part and each unit to cause the cutting tool 1 to perform various operations including each operation related to the foreign matter detection method on the holding surface according to the first embodiment. The control unit 50 includes an arithmetic processing unit having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as ROM (read only memory) or RAM (random access memory), and an input/output interface device. is a computer having The arithmetic processing device of the control unit 50 performs arithmetic processing according to a computer program stored in the storage device, and outputs a control signal for controlling the tool bit cutting device 1 to the tool bit cutting device 1 via the input/output interface device. Output to each part and each unit of

As shown in FIG. 1, the cutting tool 1 further includes cassettes 60-1 and 60-2, a carry-in/carry-out unit 61, an alignment unit 62, a carry-in unit 63, a carry-out unit 64, and a cleaning unit 65. And prepare. The cassettes 60-1 and 60-2 are containers for workpieces having a plurality of slots, and are arranged on the upper surface of the apparatus main body 2 at the ends in the -X direction. The cassette 60-1 accommodates the workpiece before cutting by the cutting tool 1, and the cassette 60-2 accommodates the workpiece after cutting by the cutting tool 1. FIG.

The carry-in/out unit 61 carries out the uncut workpiece from the cassette 60-1 to the positioning unit 62, and carries the cut workpiece from the cleaning unit 65 into the cassette 60-2.

The alignment unit 62 detects the center position and the position of the orientation flat or notch of the uncut work carried out from the cassette 60-1 to perform center alignment and direction alignment. The loading unit 63 loads the pre-cut workpiece aligned by the alignment unit 62 onto the holding surface 11 of the holding table 10 at the loading/unloading position.

The unloading unit 64 unloads the cut workpiece from the holding surface 11 of the holding table 10 at the loading/unloading position to the cleaning unit 65 . The cleaning unit 65 cleans the workpiece that has been cut, and removes contamination such as cutting chips adhering to the cut surface that has been cut.

A work piece 100 (see FIG. 5 etc.), which is an object to be cut when the tool cutting device 1 performs the method for detecting a foreign object on a holding surface, is actually turned-cut by the tool cutting device 1 and after turning-cutting. , is different from the above-mentioned workpiece to be cleaned, and in order to confirm whether or not foreign matter adheres to the holding surface 11, the cutting tool 1 turns and cuts the workpiece. In the first embodiment, the workpiece 100 is, for example, a disk-shaped wafer or the like whose base material is silicon, sapphire, gallium arsenide, or the like. The workpiece 100 has a flat front surface 101 and a rear surface 102 opposite to the front surface 101 . In the first embodiment, the workpiece 100 does not have a device formed on the surface 101, and is, for example, a dummy wafer. If the workpiece 100 is a dummy wafer or other device on which no device is formed, interference fringes 300 (see FIG. 7 ) can be suppressed, and the cutting tool 1 can inexpensively implement the foreign matter detection method on the holding surface according to the first embodiment. In the present invention, the workpiece 100 is not limited to one on which no device is formed, and may be a semiconductor wafer, an optical device wafer, or the like having a device formed on the surface 101 thereof.

FIG. 4 is a flow chart showing the processing of the foreign matter detection method for the holding surface according to the first embodiment. The foreign matter detection method on the holding surface according to the first embodiment is carried out by the cutting tool 1, and as shown in FIG. , a determination step ST15, and a cleaning step ST16. The holding surface foreign matter detection method according to the first embodiment is a method for detecting whether or not there is a foreign matter 500 (see FIGS. 9 and 10) on the holding surface 11 of the holding table 10 of the cutting tool 1. This is a method for checking whether or not the holding surface 11 of the holding table 10 of the device 1 is flat.

FIG. 5 is a cross-sectional view showing resin coating step ST11 in FIG. The resin coating step ST11 is a step of coating the surface 101 of the workpiece 100 with the resin 201, as shown in FIG.

Specifically, in the resin coating step ST11, first, as shown in FIG. In the resin coating step ST11, the resin supply part 73 of the resin coating unit 70 drops the resin liquid 200 toward the exposed surface 101 of the workpiece 100 held by the holding surface 72. and supply. Here, the resin liquid 200 contains the resin 201, and is obtained by dispersing the resin 201 with a volatile solvent to form a coating liquid.

In the resin coating step ST11, after the resin liquid 200 is supplied, the holding table 71 is rotated around the axis along the direction orthogonal to the holding surface 72, so that the workpiece 100 is moved through the holding table 71 and the workpiece 100. A centrifugal force is applied to the resin liquid 200 on the surface 101 of the object 100, and the resin liquid 200 is thinly spread and applied to the entire surface 101 of the workpiece 100 by the centrifugal force. In the resin coating step ST11, a thin film of resin 201 is formed on the surface 101 of the workpiece 100 by evaporating the solvent in the resin liquid 200 that has been spread and applied thinly.

In addition, in the resin coating step ST11, the thin film-like resin 201 may be formed on the surface 101 of the workpiece 100 by forming only one layer, or by overlapping two or more layers. In the resin coating step ST11, the same resin liquid 200 is used not only when only one layer of the thin film-like resin 201 is formed, but also when two or more layers are stacked. An integral thin film of resin 201 can be formed on the surface 101 of the workpiece 100 .

Further, in the resin coating step ST11, it is preferable to heat and cure the resin 201 formed on the surface 101 of the workpiece 100 using a heating device (not shown) according to the type of the resin 201 . In the resin coating step ST11, when two or more layers of the resin 201 are formed, it is preferable that the two or more layers of the resin 201 are heated and cured at the end.

Any material is suitable for the resin 201 contained in the resin liquid 200 used in the resin coating step ST11 as long as the surface roughness of the surface to be cut after cutting is smaller than that of the workpiece 100. can be used for In the first embodiment, the resin 201 contained in the resin liquid 200 used in the resin coating step ST11 is specifically a resin used as a positive resist film, a resin used as a water-soluble resist film, or a photopolymerization resin. A resin or the like that is used as a mold resist film can be preferably used. Examples of the resin used as the positive resist film used for the resin 201 in the resin coating step ST11 include naphthoquinonediazide sulfonic acid ester of a photosensitizer, an organic alkaline aqueous solution, a soluble novolac resin, and the like. The resin used as the water-soluble resist film used for the resin 201 in the resin coating step ST11 includes, for example, casein, a water-soluble resin to which dichromate is added, and the like. As the resin 201 used in the resin coating step ST11 and used as a photopolymerization type resist film, for example, a predetermined polymer, monomer, or the like can be used.

As the resin 201 in the resin coating step ST11, when using the above-mentioned resin used as a positive resist film or a resin used as a photopolymerization type resist film, the resin 201 is preferably cured by heating. In this case, heat curing of the resin 201 prevents the surface to be cut from being roughened due to adhesion of the resin 201 to the cutting edge of the cutting tool 22 or being stretched in the later-described processing step ST13. As a result, confirmation of the state of the cutting edge of the cutting tool 22 and confirmation of accuracy can be carried out favorably. Further, in the case where the resin used as the water-soluble resist film mentioned above is used as the resin 201 in the resin coating step ST11, the resin 201 adheres to the cutting edge of the cutting tool 22 in the later-described processing step ST13 after curing. The resin 201 does not need to be heat-cured because the possibility of it being stretched or stretched is sufficiently low.

FIG. 6 is a sectional view showing holding step ST12 and processing step ST13 in FIG. The holding step ST12 is a step of holding the back surface 102 side of the workpiece 100 coated with the resin 201 on the holding table 10, as shown in FIG.

Specifically, the holding step ST12 is performed with the holding table 10 positioned at the carry-in/out position. In the holding step ST12, the uncut workpiece 100 unloaded from the cassette 60-1 by the loading/unloading unit 61 and aligned by the positioning unit 62 is held by the loading unit 63 on the back surface 102 side of the workpiece 100. toward the holding surface 11, and loaded onto the holding surface 11 of the holding table 10 at the loading/unloading position. In the holding step ST12, the holding table 10 holds the back surface 102 opposite to the surface 101 coated with the resin 201 by the holding surface 11, so that the surface 101 coated with the resin 201 is vertically upward. , and substantially held toward the cutting unit 20 .

The machining step ST13 is a step of cutting the workpiece 100 from the surface 101 side of the workpiece 100 to a thickness where the resin 201 is not completely removed by the cutting unit 20, as shown in FIG. Here, cutting the workpiece 100 to a thickness at which the resin 201 is not completely removed means that the workpiece 100 itself is not cut, and only the resin 201 coated on the surface 101 side of the workpiece 100 is cut. This means that the resin 202 after cutting, which is thinner than the resin 201, remains on the entire surface 101 side of the workpiece 100 by reducing the thickness.

Specifically, in the processing step ST13, first, the cutting feed unit 40 moves the cutting unit 20 downward in the vertical direction so that the cutting surface of the cutting tool 22 is sucked and held by the holding surface 11 of the holding table 10. and the upper surface of the thin film-like resin 201 formed on the surface 101 of the workpiece 100 in the resin coating step ST11. In the processing step ST<b>13 , for example, the cutting feed unit 40 moves the height of the tip of the cutting tool 22 directed downward in the vertical direction to a position for cutting into the resin 201 .

Next, in the processing step ST13, the motor 24 rotates the bite wheel 23 including the bite tool 22 attached to the tip of the spindle 21 . In the processing step ST13, the processing feed unit 30 moves the holding table 10 holding the workpiece 100 from the loading/unloading position to the processing position while rotating the cutting tool wheel 23 including the cutting tool 22. move. As a result, in the processing step ST13, the tip of the cutting tool 22 is applied to the thin film-like resin 201 formed on the surface 101 of the workpiece 100 sucked and held by the holding surface 11 of the holding table 10 in the circumferential direction. contact from. Then, in the processing step ST13, the processing feed unit 30 moves the holding table 10 completely to the processing position, so that the cutting tool 22 moves the thin film-like resin 201 formed on the surface 101 of the workpiece 100. is cut over the entire surface to a thickness at which the resin 201 is not completely removed, and a resin 202 after cutting is obtained.

In the processing step ST13, the cutting tool 22 of the cutting unit 20 cuts the resin 201 on the surface 101 of the workpiece 100 over the entire surface to form the resin 202. is moved from the processing position to the loading/unloading position.

In the workpiece removal step ST14, the workpiece 100 is removed from the holding table 10 after the machining step ST13 and before the determination step ST15 is performed, and the thickness of the workpiece 100 caused by the foreign matter 500 is removed from the surface 101 side of the workpiece 100. This is the step of transferring the unevenness. Here, the irregularities in thickness caused by the foreign matter 500 on the surface 101 side of the workpiece 100 are removed by turning and holding the workpiece 100 on the holding surface 11 to which the foreign matter 500 adheres. It means that the thickness varies, that is, the thickness of the workpiece 100 becomes non-uniform.

Specifically, in the work piece removal step ST14, first, after the processing step ST13 is performed, the carry-out unit 64 moves the resin 202 after cutting onto the surface 101 from the holding table 10 positioned at the carry-in/out position. The formed workpiece 100 is removed.

Concavities and convexities are formed on the surface of the resin 202 of the workpiece 100 after cutting, which is coated on the surface 101 of the workpiece 100 taken out in the workpiece removing step ST14. Specifically, the surface of the resin 202 after the cutting process becomes convex in the region of the surface 101 of the workpiece 100 on the portion where the foreign matter 500 adheres to the holding surface 11, and unevenness is formed. As described above, according to the present invention, while the workpiece 100 is held by the holding table 10 , the thickness of the workpiece 100 varies due to the foreign matter 500 . Since the surface (the back surface 102 in this embodiment) is uneven and the surface opposite to the exposed surface (the front surface 101 in this embodiment) of the workpiece 100 is flat, interference fringes are generated in visible light. Hard to confirm. However, by removing the workpiece 100 from the holding table 10 in the workpiece removing step ST14, the unevenness due to the foreign matter is transferred to the surface 101 side, so that the interference fringes are easily visible even with visible light. When the thickness of the workpiece 100 varies due to the foreign matter 500 , the unevenness of the thickness is transferred to the front surface 101 of the workpiece 100 .

FIG. 7 is a top view schematically showing interference fringes 300 formed through processing step ST13 of FIG. The interference fringes 300 are caused by an optical phenomenon due to unevenness in the thickness of the resin 202 after cutting. Therefore, as shown in FIG. 7, the interference fringes 300 are expressed as a group of contour lines that are curves connecting positions of equal thickness in the resin 202 after cutting. The interference fringes 300, that is, the density of isobath lines, represent the slope of the amount of change in the thickness of the resin 202 after cutting.

The judgment step ST15 is a step for judging whether or not the state of the interference fringes 300 formed in the resin 202 after cutting after the processing step ST13 is performed exceeds a predetermined allowable range. In the foreign matter detection method for the holding surface according to the first embodiment, when the state of the interference fringes 300 formed on the resin 202 after cutting exceeds the predetermined allowable range (Yes in determination step ST15), the process proceeds to cleaning step ST16. Proceeding, if the state of the interference fringes 300 formed in the resin 202 after cutting does not exceed the predetermined allowable range, that is, if it is within the allowable range (No in judgment step ST15), the process is performed without executing the cleaning step ST16. terminate. Here, in the present embodiment, the state of the interference fringes 300 exceeding the predetermined allowable range means that the interference fringes 300 can be recognized by visible light, and that the state of the interference fringes 300 is within the predetermined allowable range. is a case where the interference fringes 300 cannot be recognized with visible light.

Specifically, in determination step ST15, when the interference fringes 300 can be recognized by visible light, it is determined that the state of the interference fringes 300 exceeds a predetermined allowable range, and the holding surface 11 of the holding table 10 is not sufficiently flat. It is determined that there is no foreign matter 500 on the holding surface 11 of the holding table 10 (Yes in judgment step ST15). If the interference fringes 300 cannot be recognized with visible light, it is determined that the state of the interference fringes 300 is within a predetermined allowable range. It is determined that the holding surface 11 of the holding table 10 is sufficiently flat and the foreign matter 500 does not exist on the holding surface 11 of the holding table 10 (No in judgment step ST15).

Further, in judgment step ST15, when the interference fringes 300 can be recognized by visible light, the area where the interference fringes 300 can be recognized corresponds to the area where the foreign matter 500 exists on the holding surface 11 of the holding table 10. can be recognized as

Note that, in the first embodiment, the determination step ST15 may be mechanically performed by the control unit 50 using a predetermined imaging device, a predetermined image analysis device, or the like. The formed workpiece 100 may be visually observed, and the area of the interference fringes 300, for example, the center of the interference fringes 300 where the thickness is the thinnest in the interference fringes 300 and the outer side of the interference fringes 300 A thickness measurement may be performed to determine whether there is a thickness difference equal to or greater than a threshold value.

The cleaning step ST16 is a step of cleaning the holding surface 11 of the holding table 10 when the state of the interference fringes 300 formed on the resin 202 after cutting exceeds a predetermined allowable range. That is, the cleaning step ST16 is performed only when Yes is determined in the determination step ST15.

FIG. 8 is a flow chart showing detailed processing of the cleaning step ST16 of FIG. In Embodiment 1, the cleaning step ST16 has an organic solvent supply step ST21 and a foreign matter removal step ST22, as shown in FIG. Note that the cleaning step ST16 is not limited to this form in the present invention, and may be of any form as long as the foreign matter 500 adhering to the holding surface 11 of the holding table 10 can be removed.

FIG. 9 is a cross-sectional view showing the organic solvent supply step ST21 in FIG. The organic solvent supply step ST21 is a step of supplying the organic solvent 400 to the holding surface 11, as shown in FIG.

In the organic solvent supply step ST21, specifically, as shown in FIG. The organic solvent 400 is supplied toward the upper surface of the . In the organic solvent supply step ST21, the organic solvent 400 can be supplied by a method such as dropping, spraying, spraying, or coating. In the organic solvent supply step ST21, if the area where the foreign matter 500 exists on the holding surface 11 of the holding table 10 was obtained in the previous determination step ST15, the organic solvent is supplied only to the area where the foreign matter 500 exists and its surroundings. 400 may be supplied. In the organic solvent supply step ST21, by supplying the organic solvent 400 to the area where the foreign matter 500 exists, even if the foreign matter 500 adheres to the holding surface 11, the organic solvent 400 does not adhere to the holding surface 11. 11 can be suitably wetted and can enter between the holding surface 11 and the foreign object 500 , so that the foreign object 500 can be suitably floated from the holding surface 11 .

In Embodiment 1, the organic solvent 400 used in the organic solvent supply step ST21 includes, for example, ethanol, methanol, isopropyl alcohol (IPA), n-propyl alcohol (NPA), acetone, and the like. .

FIG. 10 is a cross-sectional view showing the foreign matter removal step ST22 of FIG. The foreign matter removing step ST22 is a step of cleaning the foreign matter 500 floating up from the holding surface 11 with the organic solvent 400, as shown in FIG.

Specifically, in the foreign matter removing step ST22, as shown in FIG. 10, the cleaning brush 82 of the holding table cleaning unit 80 is moved relatively horizontally while being pressed against the holding surface 11 with a predetermined pressure. The organic solvent 400 removes the foreign matter 500 floating up from the holding surface 11 from the holding surface 11 by rubbing against the holding surface 11 . Further, in the foreign matter removing step ST22, the foreign matter 500 floating up from the holding surface 11 may be removed from the holding surface 11 by supplying two-fluid cleaning water in which air and water are mixed.

As described above, in the holding surface foreign matter detection method according to the first embodiment, by performing the cleaning step ST16, the foreign matter 500 is removed from the holding surface 11 of the holding table 10, and the holding surface 11 of the holding table 10 is sufficiently cleaned. can be returned to a flat normal state.

In the holding surface foreign matter detection method according to the first embodiment, the workpiece 100 whose surface 101 is coated with the resin 201 in the resin coating step ST11 is held by the holding surface 11 for detecting the presence or absence of the foreign matter 500 in the holding step ST12. Then, in the processing step ST13, the resin 201 is cut to a thickness that is not completely removed. For this reason, in the method for detecting foreign matter on the holding surface according to the first embodiment, the resin 201 with high toughness is coated and processed. A state in which the surface roughness of the surface is small can be formed. As a result, the foreign matter detection method for the holding surface according to the first embodiment can detect the resin 202 formed by cutting even with visible light without using a special measuring instrument such as a laser interferometer as in the conventional art. The interference fringes 300 caused by thickness variations can be observed clearly enough.

In the holding surface foreign matter detection method according to the first embodiment, the upper surface of the resin 201 covering the workpiece 100 is flattened in the processing step ST13. For this reason, in the method for detecting foreign matter on the holding surface according to the first embodiment, in the processing step ST13, the resin 202 after the cutting process is treated with the foreign matter 500 caused by the foreign matter 500 on the holding surface 11 of the holding table 10. The thickness of the workpiece 100 may be uneven based on the in-plane thickness variations.

As described above, in the foreign matter detection method on the holding surface according to the first embodiment, it is determined in determination step ST15 whether or not the state of the interference fringes 300 formed in the resin 202 after cutting exceeds the predetermined allowable range. Therefore, it is possible to determine whether or not there is a foreign object 500 on the holding surface 11 of the holding table 10. Therefore, it is possible to more easily detect the foreign object 500 on the holding surface 11 of the holding table 10. becomes.

Further, in the foreign matter detection method on the holding surface according to the first embodiment, the workpiece 100 is removed from the holding table 10 and the surface 101 of the workpiece 100 is removed after performing the processing step ST13 and before performing the determination step ST15. A workpiece removal step ST14 is performed to transfer the unevenness of the thickness caused by the foreign matter 500 to the side. For this reason, in the holding surface foreign matter detection method according to the first embodiment, since the unevenness due to the foreign matter is transferred to the surface 101 side, the interference fringes are more easily visible even with visible light. This has the effect of making it possible to detect the foreign object 500 more easily.

Further, in the foreign matter detection method for the holding surface according to the first embodiment, the cleaning step ST16 includes the organic solvent supplying step ST21 for supplying the organic solvent 400 to the holding surface 11, and the foreign matter 500 lifted up from the holding surface 11 by the organic solvent 400. and a foreign matter removing step ST22 for cleaning the . For this reason, the method for detecting a foreign object on the holding surface according to the first embodiment preferably removes the foreign object 500 from the holding surface 11 even when the foreign object 500 detected through the judgment step ST15 adheres to the holding surface 11 of the holding table 10. There is an effect that it can be removed.

[Embodiment 2]
A foreign matter detection method on a holding surface according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 11 is a cross-sectional view showing the holding step ST12 and the processing step ST13 in the foreign matter detection method for the holding surface according to the second embodiment. In FIG. 11, the same reference numerals are assigned to the same parts as those of the first embodiment, and the description thereof is omitted.

A foreign matter detection method for a holding surface according to a second embodiment of the present invention is a method implemented in a grinding apparatus 1-2 shown in FIG. As shown in FIG. 11, a grinding apparatus 1-2 that implements the method for detecting foreign matter on the holding surface according to the second embodiment is a cutting unit 1 that implements the method for detecting foreign matter on the holding surface according to the first embodiment. 20, a grinding unit 90 is provided.

In the grinding apparatus 1-2, the holding table 10 has a loading/unloading position for loading/unloading the workpiece 100 and a processing position for grinding the workpiece 100 held by the holding surface 11 by the grinding unit 90. Between, it is provided so as to be movable in the X-axis direction.

The grinding unit 90 includes a spindle 91, a grinding wheel 93 including a grinding wheel 92, and a motor 94, as shown in FIG. The axial direction of the spindle 91 is arranged along the vertical direction, which is the direction orthogonal to the holding surface 11 . The grinding wheel 93 is mounted on the leading end of the spindle 91 with the grinding wheel 92 directed downward in the vertical direction and the upper side in the vertical direction. A motor 94 is provided on the spindle 91 and rotates the spindle 91 around its axis. The grinding unit 90 grinds the workpiece 100 held on the holding table 10 by rotating a grinding wheel 93 including a grinding wheel 92 attached to the tip of the spindle 91 with a motor 94 . The grinding surface of the grinding unit 90 and the surface of the workpiece 100 to be ground by the grinding unit 90 are parallel to the holding surface 11, that is, substantially parallel to the horizontal XY plane.

In the grinding apparatus 1-2, the cutting feed unit 40 moves the grinding unit 90 mounted via the movable base along the Z-axis direction. In the grinding apparatus 1-2, the cutting feed unit 40 moves the grinding unit 90 along the -Z direction, which is vertically downward, and holds the grinding wheel 92 on the holding surface 11 of the holding table 10 by suction. move toward

The method for detecting foreign matter on the holding surface according to the second embodiment of the present invention is obtained by changing the processing step ST13 in the method for detecting foreign matter on the holding surface according to the first embodiment of the present invention. is similar to

The processing step ST13 according to the second embodiment, as shown in FIG. 11, is a step of grinding the workpiece 100 from the surface 101 side of the workpiece 100 to a thickness at which the resin 201 is not completely removed by the grinding unit 90. .

Specifically, in the processing step ST13 according to the second embodiment, first, the processing feed unit 30 moves the holding table 10 that holds the workpiece 100 from the loading/unloading position to the processing position. In the processing step ST13, the motor 94 then rotates the grinding wheel 93 including the grinding wheel 92 attached to the tip of the spindle 91 . In the processing step ST13 according to the second embodiment, the cutting feed unit 40 moves the grinding unit 90 downward in the vertical direction while rotating the grinding wheel 93 including the grinding wheel 92. The grinding surface is approached toward the holding surface 11 of the holding table 10 at the machining position. As a result, in the processing step ST13 according to the second embodiment, the tip of the grinding wheel 92 adheres to the thin film resin 201 formed on the surface 101 of the workpiece 100 sucked and held by the holding surface 11 of the holding table 10. On the other hand, contact is made from the upper surface side.

Then, in the processing step ST13 according to the second embodiment, the surface 101 of the workpiece 100 suction-held by the holding surface 11 of the holding table 10 is held by the grinding surface of the grinding wheel 92, and the surface 101 of the workpiece 100 is held by the holding surface 11 of the holding table 10. By moving to a height between the thin film resin 201 formed on the surface 101 of the workpiece 100 and the upper surface of the thin film resin 201, the grinding wheel 92 moves the thin film resin 201 formed on the surface 101 of the workpiece 100. , the resin 201 is ground over the entire surface to a thickness at which the resin 201 is not completely removed, and the ground resin 202 is formed. In the processing step ST13, for example, the cutting feed unit 40 moves the height of the tip of the grinding wheel 92 directed downward in the vertical direction to the thickness of the thin film-like resin 201 formed on the surface 101 of the workpiece 100. Grinding is performed by moving to the vicinity of the center in the thickness direction.

In the holding surface foreign matter detection method according to the second embodiment, similarly to the holding surface foreign matter detection method according to the first embodiment, the workpiece 100 whose surface 101 is coated with the resin 201 in the resin coating step ST11 is coated with the resin 201 in the holding step ST12. is held on the holding surface 11 where the presence or absence of the foreign matter 500 is to be detected, and in the processing step ST13, the resin 201 is ground to a thickness that is not completely removed. In the holding surface foreign matter detection method according to the second embodiment, similarly to the holding surface foreign matter detection method according to the first embodiment, the resin 202 after grinding is applied to the holding surface 11 of the holding table 10 in the processing step ST13. When there is a foreign substance 500 in the surface of the workpiece 100 , the workpiece 100 may have unevenness in thickness based on the in-plane thickness variation of the workpiece 100 caused by the foreign substance 500 . Therefore, the method for detecting foreign matter on the holding surface according to the second embodiment has the same effects as the method for detecting foreign matter on the holding surface according to the first embodiment.

Next, the inventors of the present invention confirmed the effect of the foreign matter detection method for the holding surface of the present invention. The results are shown in Table 1 below. In Table 1, circles indicate the interference fringes 300 that could be recognized with visible light after cutting the surface, and crosses indicate the cases where the interference fringes 300 could not be recognized with visible light.

In Method 1 of the present invention in Table 1, in the method for detecting foreign matter on the holding surface according to Embodiment 1, a naphthoquinonediazide sulfonate ester of a photosensitive agent, which is an example of a resin used as a positive resist film in the resin coating step ST11, is used. The resin liquid 200 contained as the resin 201 is used to coat the front surface 101 of the workpiece 100 , and the coated resin 201 is cured by heating to remove the foreign matter 500 from the back surface 102 side of the workpiece 100 coated with the resin 201 . The resin 201 is held by the holding surface 11 of the holding table 10, and cut with a cutting tool 22 to a thickness that does not completely remove the resin 201, thereby forming the resin 202 after cutting. In the method 2 of the present invention in Table 1, the resin 201 is changed to casein, which is an example of a resin used as a water-soluble resist film, and the coated resin 201 is not heat-cured. The same processing as 1 is executed. In the method 3 of the present invention in Table 1, the same processing as the method 1 of the present invention in Table 1 was performed except that the resin 201 was changed to a predetermined polymer, which is an example of a resin used as a photopolymerization resist film. It is. In the method 4 of the present invention in Table 1, the same processing as the method 1 of the present invention in Table 1 was performed except that the cutting with the cutting tool 22 was changed to the grinding with the grinding wheel 92 . In the comparative example in Table 1, the surface 101 of the workpiece 100 was not coated with the resin 201, and instead of the resin 201, the surface 101 of the workpiece 100 was cut. performed the same processing as

According to Table 1, in the comparative example, the interference fringes 300 could not be recognized with visible light, whereas the present invention method 1, the present method 2, the present method 3, and the present method 4 interfered with visible light. A stripe 300 was recognized. Therefore, according to Table 1, by coating the resin 201 in the resin coating step ST11, processing the resin 201 to a thickness that does not completely remove the resin 201, and forming the resin 202 after processing, interference fringes 300 can be made recognizable.

In addition, this invention is not limited to the said embodiment. That is, various modifications can be made without departing from the gist of the present invention.

1 Bite Cutting Device 1-2 Grinding Device 10, 71 Holding Table 11, 72 Holding Surface 20 Cutting Unit 21, 91 Spindle 22 Bite Tool 23 Bite Wheel 90 Grinding Unit 92 Grinding Whetstone 93 Grinding Wheel 100 Workpiece 101 Front Side 102 Back Side 201 , 202 resin 300 interference fringes 400 organic solvent 500 foreign matter

Claims (4)

A cutting tool comprising a holding table for holding a workpiece on a holding surface, and a cutting unit for cutting the workpiece held on the holding table with a cutting wheel including a cutting tool attached to the tip of a spindle. A method for detecting a foreign object on a holding surface of an apparatus, comprising:
a resin coating step of coating the surface of the workpiece with a resin;
a holding step of holding the back side of the resin-coated workpiece on a holding table;
A processing step of cutting the workpiece from the surface side of the workpiece to a thickness at which the resin is not completely removed by the cutting unit;
a determination step of determining whether the state of the interference fringes formed in the resin after the processing step exceeds a predetermined allowable range;
a cleaning step of cleaning the holding surface of the holding table when the allowable range is exceeded;
A foreign matter detection method for a holding surface, comprising: A holding surface of a grinding apparatus comprising a holding table for holding a workpiece on a holding surface, and a grinding unit for grinding the workpiece held on the holding table with a grinding wheel attached to the tip of a spindle. A foreign object detection method comprising:
a resin coating step of coating the surface of the workpiece with a resin;
a holding step of holding the back side of the resin-coated workpiece on a holding table;
A processing step of grinding the workpiece from the surface side of the workpiece to a thickness at which the resin is not completely removed by the grinding unit;
a determination step of determining whether the state of the interference fringes formed in the resin after the processing step exceeds a predetermined allowable range;
a cleaning step of cleaning the holding surface of the holding table when the allowable range is exceeded;
A foreign matter detection method for a holding surface, comprising: After performing the processing step and before performing the determining step, the method further includes a step of removing the workpiece from the holding table and transferring the thickness unevenness caused by the foreign matter to the surface side of the workpiece. 3. The foreign matter detection method for a holding surface according to claim 1 or 2, characterized in that: The washing step comprises
an organic solvent supplying step of supplying an organic solvent to the holding surface;
a foreign matter removing step of cleaning foreign matter floating up from the holding surface with the organic solvent;
4. The foreign matter detection method for a holding surface according to any one of claims 1 to 3, characterized by comprising:

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