Processing method

Abstract

To provide a processing method of processing a wafer while supplying processing water, capable of solving the problem of contamination due to deposition of processing water including processed wastes in a processing area.SOLUTION: A processing method using a processing device 1 composed of a chuck table 52 for holding a wafer W and processing means 3 for applying processing to the wafer W held by the chuck table 52 while supplying processing water L includes a holding step of holding the wafer W on the chuck table 51 and a processing step of applying processing to the wafer W held by the chuck table 52 while supplying the processing water L, wherein at least before the processing step, a semi-solid body deposition step is included that deposits a semi-solid body 60 with a surfactant fixed using a stabilizer to a processing area where the processing water L including processed wastes scatter. In the processing step, the semi-solid body 60 is gradually dissolved by the processing water and the processing water including processed wastes is discharged from the processing area.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a processing method using a processing apparatus including a chuck table for holding a wafer, and processing means for processing the wafer held on the chuck table while supplying processing water thereto. [Background technology]

[0002] A wafer has a number of devices such as ICs and LSIs formed on its front surface, separated by planned dividing lines. The back surface is ground by a grinding device to form the wafer into a specified thickness. The wafer is then divided into individual device chips by a cutting device for use in electrical devices such as mobile phones and personal computers.

[0003] The grinding apparatus includes a chuck table for holding the wafer, a grinding means having a rotatably mounted grinding wheel with a ring-shaped arrangement of grinding stones for grinding the wafer held on the chuck table, and a grinding water supply means for supplying grinding water to the wafer and the grinding stones, and is capable of grinding the wafer to the desired thickness (see, for example, Patent Document 1).

[0004] The cutting apparatus is configured to include a chuck table that holds the wafer, cutting means having a rotatably mounted cutting blade that cuts the wafer held on the chuck table, and cutting water supply means that supplies cutting water to the wafer and the cutting blade, and is capable of cutting the wafer with high precision and dividing it into individual device chips (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-016770 A [Patent Document 2] JP 2014-079833 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, among the wafers to be processed, there are wafers that contain iron components, for example, PKG wafers. When such wafers are ground by a grinding device, grinding water that contains grinding debris of iron components scatters in the processing area and adheres to the surrounding area, causing rust over time and contaminating the processing area.

[0007] Such a problem is not limited to the grinding device, but can also occur in a cutting device that performs cutting while supplying cutting water. In addition, when processing a wafer by grinding or cutting, various substances that constitute the wafer become processing waste and are scattered into the processing area together with the grinding water or cutting water, so contamination of the processing area is not limited to the processing of a wafer that contains iron components, but can occur in all processing methods that process wafers while supplying processing water.

[0008] The present invention has been made in consideration of the above-mentioned facts, and its main technical object is to provide a processing method that can solve the problem that, when processing is performed while processing water is being supplied to a wafer, processing water containing processing debris adheres to and contaminates the processing area. [Means for solving the problem]

[0009] In order to solve the above-mentioned main technical problems, according to the present invention, there is provided a processing method using a processing apparatus comprising a chuck table for holding a wafer, and processing means for processing the wafer held on the chuck table while supplying processing water to the wafer held on the chuck table, the processing method comprising: a holding step for holding a wafer on the chuck table; and a processing step for processing the wafer held on the chuck table while supplying processing water to the wafer, and a semi-solid body adhering step for adhering a semi-solid body having a surfactant fixed with a stabilizer to a processing area where processing water containing processing debris is scattered at least before the processing step, wherein in the processing step, the semi-solid body is gradually dissolved by the processing water, and the processing water containing the processing debris is discharged from the processing area.

[0010] The surfactant preferably contains either polyoxyalkylene glycol or alkyl betaine, and the stabilizer preferably contains either gelatin, pectin, or guar gum. The processing means may be a grinding means having a grinding wheel rotatably mounted thereon, the grinding wheels being annularly arranged, and the workpiece may contain an iron component. Effect of the Invention

[0011] The processing method of the present invention is a processing method using a processing apparatus comprising a chuck table for holding a wafer and processing means for processing the wafer held on the chuck table while supplying processing water to the wafer held on the chuck table, and comprises a holding step for holding a wafer on the chuck table, and a processing step for processing the wafer held on the chuck table while supplying processing water to the wafer, and comprises at least a semi-solid body adhering step for adhering a semi-solid body having a surfactant fixed with a stabilizer to an area where processing water containing processing debris is scattered before the processing step, and in the processing step, the semi-solid body is gradually dissolved by the processing water and the processing water containing processing debris is discharged from the processing area, so that the processing area is constantly cleaned by the action of the surfactant dissolving from the semi-solid body, and the processing water containing processing debris flows to a drain without adhering to the processing area, eliminating the problem of processing debris adhering to the processing area and contaminating the processing area over time. [Brief description of the drawings]

[0012] [Figure 1] 1 is an overall perspective view of a grinding device according to an embodiment of the present invention; [Diagram 2] 2 is a perspective view of a semi-solid body attached to the grinding device shown in FIG. 1. [Diagram 3] 2 is a perspective view showing an embodiment of a holding step for holding a wafer on a chuck table of the grinding apparatus shown in FIG. 1. [Figure 4] 2 is a perspective view showing an embodiment of a processing step performed by the grinding device shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a processing method configured based on the present invention will be described in detail with reference to the accompanying drawings.

[0014] 1 shows an overall perspective view of a grinding apparatus 1 suitable for carrying out the processing method of the present invention. The grinding apparatus 1 includes a roughly rectangular parallelepiped housing 2, which includes a grinding means 3 for grinding a wafer W as a workpiece, a holding means 5 including a chuck table 52 configured to hold and rotate the wafer W, a first cassette 6 arranged on the front side in the figure for accommodating the wafer W before grinding, a second cassette 7 arranged on the other side of the first cassette 6 in the X-axis direction in the figure for accommodating the wafer W after grinding, a temporary placement means 8 arranged adjacent to the first cassette 6 in the Y-axis direction in the figure for aligning the center of the wafer W, a cleaning means 9 arranged adjacent to the second cassette 7 in the Y-axis direction, and a cleaning means 10 housed in the first cassette 6. The apparatus includes a first transport means 10 for transporting the wafer W to the temporary placement means 8 and transporting the wafer W that has been ground and cleaned by the cleaning means 9 to the second cassette 7, a second transport means 11 for transporting the wafer W placed on the temporary placement means 8 and centered onto the chuck table 52 of the holding means 5 positioned in the carry-in / out area (front side in the figure), a third transport means 12 for transporting the wafer W after grinding from the chuck table 52 positioned in the carry-in / out area to the cleaning means 9, a dust cover 14 for covering a processing area where the wafer W held on the chuck table 52 is ground by a grinding wheel 34, and a control means (not shown). For convenience of explanation, in FIG. 1, the dust cover 14 is shown removed upward from a predetermined position (indicated by a dashed line) covering the processing area. Furthermore, the wafer W processed by the grinding device 1 is, for example, a PKG wafer that is composed of a resin part that protects the semiconductor element from the outside and an external terminal for electrically connecting the semiconductor element, and contains iron components in the area where grinding is performed.

[0015] The grinding means 3 is mounted so as to be movable in the vertical direction along a pair of guide rails 22, 22 extending in the vertical direction on the inner surface of the support wall 21 erected on the rear end side of the device housing 2. The grinding means 3 includes a unit housing 31, a wheel mount 33 disposed on the lower end of a rotating shaft 32 rotatably supported by the unit housing 31, a grinding wheel 34 mounted on the wheel mount 33 and having a plurality of grinding stones 35 arranged in an annular shape on the lower surface side, an electric motor 36 mounted on the upper end of the unit housing 31 for rotating the wheel mount 33, and a movable base 38 for supporting the unit housing 31 via a support member 37. The movable base 38 is provided with a guided groove that slidably fits onto the above-mentioned guide rails 22, 22, and supports the grinding means 3 so as to be movable in the vertical direction.

[0016] The illustrated grinding device 1 includes a vertical feed means 39 for raising and lowering a moving base 38 of the grinding means 3 along the guide rails 22, 22. The vertical feed means 39 includes a pulse motor 39a, a male screw rod 39b that is arranged in the vertical direction parallel to the guide rails 22, 22, rotatably supported by the support wall 21, and rotated by the pulse motor 39a, and a female screw block (not shown) that is attached to the moving base 38 and screwed with the male screw rod 39b. The grinding means 3 can be moved in the Z-axis direction (vertical direction) by driving the male screw rod 39b forward and backward by the pulse motor 39a. Furthermore, an operation panel 15 for instructing a control means (not shown) to start and stop grinding and for specifying grinding conditions is arranged on the front side of the device housing 2 where the first conveying means 10 is arranged, and a display means (not shown) for displaying processing information and the like is also connected to the control means.

[0017] The holding means 5 includes a cover table 51 and a chuck table 52 disposed so as to protrude upward from the center of the cover table 51. The chuck table 52 is connected to a suction means (not shown) and has a breathable holding surface on which the wafer W is held, and negative pressure can be generated on the holding surface by operating the suction means. The chuck table 52 is rotatably supported and rotated by a rotation drive source (not shown). In addition, a parallel feed means (not shown) is disposed in the device housing 2 for moving the chuck table 52 in the Y-axis direction indicated by the arrow Y, which is parallel to the horizontal plane, and the chuck table 52 can be moved between a carry-in / out area on the front side in the Y-axis direction and a processing area immediately below the grinding means 3.

[0018] In addition to the above-mentioned configuration, the grinding apparatus 1 is provided with a grinding water supply means 40 for supplying grinding water L as processing water. The grinding water supply means 40 is provided with a grinding water tank 41 including a pressure pump (not shown), a grinding water supply path 42 connecting the grinding water tank 41 with the upper end 32a of the rotating shaft 32 of the grinding means 3, and an opening / closing valve 44 disposed in the grinding water supply path 42. The grinding water L supplied from the grinding water tank 41 through the grinding water supply path 42 is introduced from the upper end 32a of the rotating shaft 32 and supplied to the wafer W held on the chuck table 52 from the lower surface of the grinding wheel 34.

[0019] Between the side walls 2a, 2a constituting the upper surface side of the device housing 2, and around the chuck table 52, a water pan 23 for receiving grinding water L containing grinding chips and the like is formed. Drainage ports 23a, 23a are provided on the bottom surface of the water pan 23 on the machining area side, and the grinding water L containing the grinding chips and the like that flows into the drainage ports 23a, 23a is discharged to the outside.

[0020] The dust cover 14 is provided with a cover member 14a having a substantially box shape that covers the machining area as a whole, and the cover member 14a has an upper wall 14b, a front wall 14c, and side walls 14d, 14d. The side walls 14d, 14d of the dust cover 14 have shoulder surfaces 14e, 14e facing downward, and the shoulder surfaces 14e, 14e are disposed on the upper surfaces of the side walls 2a, 2a of the device housing 2. The upper wall 14b of the cover member 14a is provided with a circular opening 14f that allows the grinding wheel 34 to pass through, and a cylindrical member 14g is provided extending upward from the periphery of the circular opening 14f. Approximately half of the cylindrical member 14g and a part of the upper wall 14b form a maintenance and inspection door 14h that can be opened and closed relative to the upper wall 14b, and a maintenance and inspection door 14i is formed adjacent to the door 14h. A suction duct 14j (only a part of which is shown) connected to a suction means (not shown) is provided on the upper wall 14b, which sucks in contaminants and the like that are scattered and floating inside the dust cover 14 and reduces the pressure inside the dust cover 14 to prevent the contaminants and the like from leaking outside the dust cover 14.

[0021] The grinding apparatus 1 suitable for the processing method of this embodiment has a configuration generally as described above, and the following describes an aspect of the processing method configured based on the present invention and carried out using the above-mentioned grinding apparatus 1.

[0022] When carrying out the processing method configured based on the present invention, a semi-solid body 60, which will be described below with reference to FIG. 2, is prepared. The semi-solid body 60 is a body in which a surfactant is fixed with a stabilizer. The semi-solid body 60 is a body in which, for example, polyoxyalkylene glycol or alkyl betaine is selected as the surfactant, and a water-soluble gelling agent, for example, gelatin, pectin, or guar gum is selected as the stabilizer, and the mixture is kneaded and semi-solidified (gelled). In the following embodiment, it is assumed that polyoxyalkylene glycol is selected as the surfactant, and gelatin is selected as the stabilizer. Gelatin has a dissolution temperature of 50 to 60°C, a gelling temperature of 15 to 25°C, and a re-dissolution temperature of 25 to 35°C, and its shape is stably maintained at the temperature (for example, 23°C) of the site where the grinding device 1 is placed. As shown in FIG. 2, the semi-solid body 60 is approximately cylindrical and has adhesiveness. The semi-solid body 60 is used in a size of, for example, about 5 cm in diameter and 1 cm in thickness. The shape of the semi-solid body 60 is not limited to this, and may be a polygonal column including a triangular or rectangular cross section, or a hemispherical shape, and the shape is arbitrary. In addition, the semi-solid body 60 is not necessarily limited to being stored in a specific shape such as the cylindrical shape described above, and may be stored in a cylindrical container (not shown) for multiple doses, and one dose of the semi-solid body 60 may be pushed out of the container and attached to a predetermined location.

[0023] (Semi-solid adhesion process) The semi-solid body 60 is prepared, and at least before the processing step described below is performed, more preferably before the holding step before the processing step, the semi-solid body attachment step is performed to attach the semi-solid body 60 to an area where processing water (grinding water) containing processing debris (grinding debris) scatters. The position where the semi-solid body 60 is attached is selected, for example, as shown in Fig. 1, near the processing area directly below the grinding means 3, on the water pan 23 that constitutes the path from the position where the chuck table 52 is positioned during grinding to the drain outlet 23a, on the inner side surface of the side wall 2a surrounding the water pan 23, and further, on the inside of the dust cover 14, preferably the upper wall 14b of the dust cover 14, more preferably the doors 14h and 14i that constitute the upper wall 14b of the dust cover 14 that are convenient for attachment.

[0024] (holding process) As described above, after the semi-solid body attachment step is performed, a holding step is performed to hold the wafer W on the chuck table 52. As shown in Fig. 3, the wafer W is accommodated in the first cassette 6 with the protective tape T attached to the front surface Wa on which the device D is formed. The holding step performed in the grinding apparatus 1 of this embodiment includes a step of operating the parallel feed means to position the chuck table 52 in the carry-in / out area on the front side in Fig. 1, a step of operating the first transport means 10 to carry out the desired wafer W from the first cassette 6 and transport it to the temporary placement means 8, a step of performing centering of the wafer W in the temporary placement means 8, a step of operating the second transport means 11 to transport the wafer W from the temporary placement means 8 to the chuck table 52 positioned in the carry-in / out area, and a step of placing the wafer W with the protective tape T side facing downward and the back surface Wb side of the wafer W facing upward as shown on the right side of Fig. 3, and operating the suction means (not shown) to hold the wafer W by suction.

[0025] (Processing process) As described above, after the holding step is performed, the processing step is performed. In the processing step, the above-mentioned parallel feed means is operated to move the chuck table 52 to the processing area directly below the grinding means 3 as shown in FIG. 4. In FIG. 4, the above-mentioned dust cover 14 is omitted for convenience of explanation, but in reality, the processing area is covered by the dust cover 14. Next, the rotating shaft 32 of the grinding means 3 is rotated in the direction indicated by the arrow R1 in FIG. 4 at, for example, 6000 rpm, while the chuck table 52 is rotated in the direction indicated by the arrow R2 at, for example, 300 rpm. Then, the above-mentioned grinding water supply means 40 is operated to supply the grinding water L to the lower side of the grinding wheel 34 via the rotating shaft 32, while the grinding stone 35 is brought into contact with the back surface Wb of the wafer W, and the grinding wheel 35 is ground and fed in the direction indicated by the arrow R3 (downward) at, for example, a grinding feed speed of 1 μm / sec. At this time, grinding can be carried out while measuring the thickness of the wafer W using a contact or non-contact measuring gauge not shown, and the back surface Wb of the wafer W is ground a predetermined amount to bring the wafer W to a predetermined thickness.

[0026] By carrying out the above-mentioned processing step, the grinding water L containing the grinding chips is scattered and dropped from the back surface Wb of the wafer W into the processing area, more specifically, into the water pan 23, the side wall 2a, and the dust cover 14 (not shown) around the cover table 51, and flows through the water pan 23 toward the drainage port 23a. In FIG. 4, for convenience of explanation, the grinding water L is illustrated as scattering only in a predetermined direction, but in reality, it is scattered over the entire processing area. Then, by the above-mentioned semi-solid body attachment step, the semi-solid body 60 is attached to the water pan 23, the inner wall of the side wall 2a, and the upper wall 14b of the dust cover 14, which form the processing area, and the grinding water L flows in contact with the semi-solid body 60, so that the surfactant contained in the semi-solid body 60 gradually dissolves and flows out, and the processing area is constantly cleaned. With the above, the processing step is completed, and the processing method of the present invention is completed.

[0027] When the above-mentioned processing steps are completed, the above-mentioned parallel feed means is operated to position the chuck table 52 in the carry-in / out area, and the third transport means 12 is operated to transport the wafer W from the chuck table 52 to the cleaning means 9, where the wafer W is cleaned and dried. Then, the first transport means 10 is operated to transport the wafer W that has been cleaned and dried from the cleaning means 9 into the second cassette 7.

[0028] According to the processing method of the embodiment described above, the processing area is always cleaned by the action of the surfactant dissolved from the semi-solid body 60, and the grinding water L containing the grinding waste flows to the drain port 23a without adhering to the processing area. In particular, when the wafer W is a PKG wafer containing an iron component as in this embodiment, the iron component contained in the grinding waste is discharged from the processing area without adhering to the surroundings, and the problem that the grinding waste containing the iron component adheres to the processing area and rust occurs over time, contaminating the processing area, is solved.

[0029] In the above embodiment, an example was described in which the processing method configured based on the present invention is applied to processing of a PKG wafer W that generates processing debris containing iron components, but the present invention is not limited to this, and may be applied when performing grinding of a wafer that does not contain iron components, for example, a silicon (Si) wafer. Even in this case, the processing area is always cleaned by the action of the surfactant that gradually dissolves from the semi-solid body 60, and the processing area is maintained in a clean state.

[0030] In the above embodiment, the processing method of the present invention is applied to the grinding process performed by the grinding device 1, but the present invention is not limited thereto. For example, the processing method configured based on the present invention may be applied when performing cutting processing to cut a wafer and divide it into individual device chips by a cutting device configured to include a chuck table that holds a wafer, a cutting means rotatably mounted with a cutting blade that cuts the wafer held on the chuck table, and a cutting water supplying means that supplies cutting water to the wafer and the cutting blade. In that case, before performing the cutting process, a semi-solid body attachment process is performed in which the semi-solid body 60 in which the surfactant is fixed with a stabilizer is attached to the processing area where the wafer is cut and the processing water (cutting water) containing the processing waste (cutting waste) is scattered. As a result, the processing area is always cleaned by the action of the surfactant dissolved from the semi-solid body 60, and the cutting water containing the cutting waste does not adhere to the processing area and flows to a drainage outlet arranged in the cutting device. As described above, when the wafer to be processed is a PKG wafer containing iron components as described above, the iron components contained in the cutting debris are discharged from the processing area without adhering to the surrounding area, thereby eliminating the problem of cutting debris containing iron components adhering to the processing area and causing rust over time to contaminate the processing area. Even if the wafer to be processed is a wafer not containing iron components, the problem of cutting debris adhering to the processing area and contaminating the processing area over time is eliminated. [Explanation of symbols]

[0031] 1: Grinding device 2: Device housing 21:Supporting wall 22: Guide rail 23: Waiter bread 23a: Drain port 3: Grinding method 31: Unit housing 32: Rotation axis 33: Wheel mount 34: Grinding wheel 35: Grinding wheel 36: Electric motor 37: Support member 38: Mobile base 39: Vertical feed means 5: Holding means 51: Cover table 52: Chuck table 6: First Cassette 7: Second Cassette 8: Temporary storage means 9: Cleaning method 10: First conveyance means 11: Second conveyance means 12: Third conveyance means 13: Grinding water nozzle 14: Dust cover 14a: Cover member 14b: Upper wall 14c: Front wall 14d: Side wall 14e:Shoulder surface 14f: Circular opening 14g: Cylindrical member 14h, 14i: Door 14j: Suction duct 15: Operation panel 40: Grinding water supply means 41: Grinding water tank 42: Grinding water supply channel 44:Shutdown valve 60: Semi-solid D: Device T: Protective tape W: Wafer Wa: Surface Wb:Back side

Claims

1. A processing method using a processing apparatus including a chuck table for holding a wafer, and a processing means for processing the wafer held on the chuck table while supplying processing water, comprising: a holding step of holding the wafer on the chuck table; a processing step of processing the wafer held on the chuck table while supplying processing water to the wafer, and a semi-solid body attaching step of attaching a semi-solid body having a surfactant fixed by a stabilizer to a processing area where processing water containing processing waste is scattered at least prior to the processing step, In the processing step, the semi-solid matter is gradually dissolved by processing water, and the processing water containing the processing waste is discharged from the processing area.

2. 2. The method according to claim 1, wherein the surfactant comprises either polyoxyalkylene glycol or alkyl betaine, and the stabilizer comprises either gelatin, pectin, or guar gum.

3. The processing means is a grinding means having a grinding wheel rotatably mounted thereon, the grinding wheels being annularly arranged, 2. The method according to claim 1, wherein the workpiece contains an iron component.

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