Fixing method of protective material

Abstract

To provide a fixing method of a protective material capable of reducing the variation in thickness of a protective material that protects an object.SOLUTION: A fixing method of a protective material for fixing a water-soluble protective material to an object includes a contacting step of bringing the object into contact with the protective material, and an attaching step of attaching the protective material to the object by supplying water to the protective material after the contacting step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for fixing a protective member to an object. [Background technology]

[0002] In the device chip manufacturing process, a wafer is used in which devices are formed in multiple areas defined by multiple intersecting streets (planned division lines). By dividing this wafer along the streets, device chips equipped with devices are obtained. The device chips are incorporated into various electronic devices such as mobile phones and personal computers.

[0003] A cutting device that cuts the wafer with an annular cutting blade can be used to divide the wafer. Recently, a process for dividing the wafer by laser processing has also been developed. For example, a laser beam is irradiated onto the wafer to perform ablation processing, and processing grooves for dividing the wafer are formed along the streets (see Patent Document 1). When laser processing is used, the processing speed can be set higher than when cutting the wafer with a cutting blade, and therefore processing efficiency is improved. Laser processing can also be applied to hard wafers that are difficult to cut with a cutting blade.

[0004] When a wafer is subjected to laser processing, processing debris such as molten material (debris) is generated in the area of ​​the wafer irradiated with the laser beam. If this processing debris adheres to the wafer or device, the wafer or device may be contaminated, and the quality of the device chip may be reduced. Therefore, a protective film may be formed on the wafer during laser processing. For example, Patent Document 2 discloses a wafer processing method in which a protective film is formed on the wafer by spin coating, and then the wafer is irradiated with a laser beam through the protective film. By covering the wafer with a protective film, processing debris generated during laser processing can be prevented from adhering to the wafer or device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-305420 [Patent Document 2] JP 2004-188475 A Summary of the Invention [Problem to be solved by the invention]

[0006] The surface of the object (such as a wafer) to be processed is not necessarily flat, and may have irregularities. For example, when bumps (protruding electrodes) are connected to a device formed on the surface side of the object, the height position of the top end of the object differs between the area where the bumps exist and the area where they do not exist, resulting in irregularities on the surface side of the object.

[0007] When a protective film is formed by spin coating on the surface side of an object having irregularities, the protective film is formed so that the height of the upper surface is approximately the same. As a result, a protective film is formed with different thicknesses in the region covering the convex parts of the object and the region covering the concave parts, and the thickness of the protective film becomes uneven. This causes the region of the protective film covering the convex parts to be relatively thin, and the protection of the object may be partially insufficient. On the other hand, if the thickness of the protective film is set so that the convex parts of the object are sufficiently covered, the time required to form the protective film increases, and productivity decreases. In addition, the region of the protective film covering the concave parts of the object may become excessively thick, which may hinder smooth processing of the object.

[0008] The present invention has been made in consideration of the above problems, and has an object to provide a method for fixing a protective member that is capable of reducing the variation in thickness of the protective member that protects an object. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a method for fixing a water-soluble protective member to an object, the method including a contact step of bringing the object into contact with the protective member, and an attachment step of attaching the protective member to the object by supplying water to the protective member after the contact step is performed.

[0010] According to another aspect of the present invention, there is provided a method for fixing a water-soluble protective member to an object, the method comprising: a water supplying step of supplying water to the object; and, after the water supplying step, attaching the protective member to the object by contacting the protective member with a surface of the object to which the water is attached.

[0011] Furthermore, according to another aspect of the present invention, there is provided a method for fixing a water-soluble protective member to an object, the method including a water supplying step of supplying water to the protective member, and an attachment step of attaching the protective member to the object by contacting the object with the protective member after the water supplying step is performed.

[0012] Preferably, the water is supplied in the form of a mist to the object or the protective member. Preferably, the protective member is attached to the object while being heated. Preferably, the object and the protective member are brought into contact with each other under a reduced pressure environment. Effect of the Invention

[0013] In a method for fixing a protective member according to one aspect of the present invention, when the protective member is fixed to an object, water comes into contact with the water-soluble protective member and a part of the protective member dissolves. This makes it possible to attach the protective member to the object along the unevenness of the object, thereby reducing the variation in thickness of the protective member caused by the unevenness of the object. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1(A) is a perspective view showing an object, and FIG. 1(B) is a front view showing the object. [Diagram 2] 10 is a flowchart showing a method for fixing the protective member. [Diagram 3] FIG. 3(A) is a partial cross-sectional front view showing the object and the protective member in the contact step, and FIG. 3(B) is a partial cross-sectional front view showing the object and the protective member after the contact step. [Figure 4] FIG. 4(A) is a partial cross-sectional front view showing the object and the protective member in the attaching step, and FIG. 4(B) is a partial cross-sectional front view showing the object and the protective member after the attaching step. [Diagram 5] FIG. 2 is a perspective view showing an object to which a protective member is fixed. [Figure 6] FIG. 2 is a partially sectional front view showing the laser processing apparatus. [Figure 7] FIG. 2 is a partially sectional front view showing the cleaning device. [Figure 8] 10 is a flowchart showing a modified example of the method for fixing the protective member. [Figure 9] FIG. 11 is a partial cross-sectional front view showing the target object and the protective member in the water supply step. [Figure 10] Fig. 10(A) is a partial cross-sectional front view showing the object and the protective member in the attaching step, and Fig. 10(B) is a partial cross-sectional front view showing the object and the protective member after the attaching step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (Embodiment 1) Hereinafter, an embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. First, a configuration example of an object to which a protective member can be fixed by the fixing method of the protective member according to this embodiment will be described. Fig. 1(A) is a perspective view showing the object 11, and Fig. 1(B) is a front view showing the object 11.

[0016] After a protective member, which will be described later, is formed on the object 11, the object is processed by laser processing or the like. That is, the object 11 corresponds to an object on which a protective member is formed and corresponds to an object to be processed that is processed in a predetermined manner. For example, the object 11 is a disk-shaped wafer (substrate) made of a semiconductor such as single crystal silicon, and has a front surface (first surface) 11a and a back surface (second surface) 11b that are generally parallel to each other.

[0017] The object 11 is divided into a plurality of rectangular regions by a plurality of streets (planned division lines) 13 arranged in a lattice pattern so as to intersect with one another. Devices 15 such as ICs (Integrated Circuits), LSIs (Large Scale Integrations), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) devices are formed in each of the plurality of regions divided by the streets 13 on the front surface 11a side of the object 11. By dividing the object 11 along the streets 13, a plurality of device chips each including a device 15 are manufactured.

[0018] However, there are no limitations on the material, shape, structure, size, etc. of the object 11. For example, the object 11 may be a wafer (substrate) made of a semiconductor other than silicon (GaAs, SiC, InP, GaN, etc.), sapphire, glass, ceramics, resin, metal, etc. In addition, there are no limitations on the type, number, shape, structure, size, arrangement, etc. of the device 15.

[0019] Unevenness is formed on the surface 11a side of the object 11. For example, a plurality of electrodes (connection electrodes) 17 protruding from the surface of the device 15 are connected to the device 15. The electrodes 17 are spherical bumps (protruding electrodes) made of a metal material such as solder, and are connected to electrodes, terminals, etc. included in the device 15. By partially providing the electrodes 17 on the surface 11a side of the object 11, unevenness is formed on the surface 11a side of the object 11.

[0020] However, the cause of the unevenness is not limited to the electrodes 17. For example, unevenness may be formed on the surface 11a side of the object 11 due to the presence or absence of the device 15 or the structure of the device 15. Furthermore, structures such as TEGs (Test Element Groups) used for inspecting the device 15 may be formed on the streets 13 of the object 11. In this case, the structures on the streets 13 may also be a cause of unevenness in the object 11.

[0021] In this embodiment, after the protective member is fixed to the object 11 having projections and recesses, a predetermined process is performed on the object 11. A specific example of the method for fixing the protective member according to this embodiment will be described below. Fig. 2 is a flowchart showing the method for fixing the protective member.

[0022] In the method for fixing a protective member according to the present embodiment, first, a water-soluble protective member is prepared, and the protective member is brought into contact with the object 11 (contact step S11). Fig. 3(A) is a partially sectional front view showing the object 11 and the protective member 19 in the contact step S11.

[0023] The protective member 19 is a sheet-like member (protective sheet) that is fixed to the object 11 and protects the object 11. The protective member 19 is made of a material that can be dissolved in water, and is water-soluble. For example, the water-soluble protective member 19 may be a sheet made of a water-soluble resin such as BVOH (butenediol-vinyl alcohol copolymer) or PVA (polyvinyl alcohol).

[0024] There are no limitations on the shape, size, thickness, etc. of the protective member 19 as long as the protective member 19 can protect the object 11. For example, the protective member 19 is formed in a circular shape with approximately the same diameter as the object 11. The thickness of the protective member 19 is set to, for example, 0.01 mm or more and 0.5 mm or less.

[0025] In the contact step S11, a fixing device (adhering device) 2 is used to attach and fix the protective member 19 to the object 11. The fixing device 2 includes a holding table 4 that holds the object 11. The upper surface of the holding table 4 is a flat surface that is approximately parallel to the horizontal plane, and constitutes a holding surface 4a that holds the object 11.

[0026] The holding table 4 may be provided with a suction path (not shown) that sucks the object 11. One end of the suction path is exposed on the holding surface 4a, and the other end of the suction path is connected to a suction source such as an ejector. When the suction force (negative pressure) of the suction source is applied to the suction path with the object 11 placed on the holding surface 4a, the object 11 is sucked and held by the holding table 4.

[0027] A heat source (heater) 6 for heating the holding table 4 is provided inside the holding table 4. For example, an electric heater is used as the heat source 6. When power is supplied to the heat source 6, the heat source 6 generates heat and the holding table 4 is heated, and the object 11 held by the holding table 4 is also heated.

[0028] A moving unit (not shown) and a rotary drive source (not shown) may be connected to the holding table 4. The moving unit is, for example, a ball screw type moving mechanism, and moves the holding table 4 in the horizontal direction (direction parallel to the holding surface 4a). The rotary drive source is, for example, a motor, and rotates (spins) the holding table 4 around a rotation axis roughly parallel to the vertical direction (direction perpendicular to the holding surface 4a).

[0029] When the protective member 19 is fixed to the object 11, first, the object 11 is held by the holding table 4. When the protective member 19 is fixed to the front surface 11a side of the object 11, the object 11 is placed on the holding table 4 so that the front surface 11a (protected surface) faces upward and the back surface 11b faces the holding surface 4a.

[0030] Next, a protective member 19 is placed on the surface 11a side of the object 11. The protective member 19 is positioned so as to cover the multiple devices 15 (see FIG. 1(A)) formed on the surface 11a side of the object 11. This brings the object 11 and the protective member 19 into contact with each other.

[0031] 3B is a partial cross-sectional front view showing the object 11 and the protective member 19 after the contact step S11. When the protective member 19 is placed on the surface 11a side of the object 11, the protective member 19 comes into contact with the tips (upper ends) of the electrodes 17. At this time, the protective member 19 may be slightly deformed so as to enter the gaps between the electrodes 17, but the overall shape of the protective member 19 is maintained in a sheet shape due to the rigidity of the protective member 19. Therefore, in the region where the electrodes 17 are not provided, a gap is formed between the surface 11a of the object 11 and the protective member 19. In other words, at the stage where the protective member 19 is brought into contact with the object 11, the protective member 19 only comes into partial contact with the electrodes 17 and does not deform to follow the surface 11a of the object 11 and the electrodes 17.

[0032] Next, water is supplied to the protective member 19 to attach the protective member 19 to the object 11 (attaching step S12). Fig. 4(A) is a partial cross-sectional front view showing the object 11 and the protective member 19 in the attaching step S12.

[0033] The fixing device 2 includes a water supply unit 8 that supplies water 10. The water supply unit 8 supplies the water 10 in a mist form (mist state) to the protective member 19. For example, the water supply unit 8 is installed above the holding surface 4a of the holding table 4, and sprays the mist-like water 10 toward the protective member 19 in contact with the object 11 held by the holding table 4.

[0034] There is no limitation on the type and configuration of the water supply unit 8 as long as it can supply mist-like water 10. For example, the water supply unit 8 can be a sprayer equipped with a spray nozzle that pressurizes water and sprays it in mist form from a spray outlet, or a sprayer that sprays water in mist form by using the Venturi effect.

[0035] The water supply unit 8 may also include a nozzle (ultrasonic nozzle) that sprays water while turning it into mist by applying ultrasonic vibration (vibration at a frequency belonging to an ultrasonic band). For example, the ultrasonic nozzle includes a storage section that temporarily stores water, and an ultrasonic vibrator that applies ultrasonic vibration to the water stored in the storage section. The ultrasonic vibrator includes a piezoelectric body (piezoelectric ceramics) made of barium titanate, lead zirconate titanate, lithium tantalate, or the like, and an electrode that is connected to the piezoelectric body and to which a high-frequency voltage is applied. When the ultrasonic vibrator is operated, ultrasonic vibration (for example, 20 kHz or more and 60 kHz or less) is applied to the water stored in the storage section. Then, the water to which the ultrasonic vibration has been applied is sprayed from the nozzle of the ultrasonic nozzle, turning the water into mist (atomization). The ultrasonic vibrator may directly apply ultrasonic vibration to the water, or may apply ultrasonic vibration to the water via another member (such as a vibration plate).

[0036] The water supply unit 8 is configured to be able to supply water 10 to the entire protective member 19. For example, a moving unit (not shown) that moves the water supply unit 8 in the horizontal direction (direction parallel to the holding surface 4a) is connected to the water supply unit 8. By moving the holding table 4 and the water supply unit 8 relatively with the moving unit, it is possible to supply mist-like water 10 to any region of the protective member 19. However, the water supply unit 8 may be configured to be able to supply water 10 to the entire protective member 19 in a state in which the holding table 4 and the water supply unit 8 are stationary.

[0037] In the attachment step S12, while the object 11 and the protective member 19 are in contact with each other, the holding table 4 and the water supply unit 8 are moved relatively as necessary, and water 10 is sprayed from the water supply unit 8. As a result, the water 10 is supplied in the form of a mist onto the entire protective member 19.

[0038] The water 10 supplied to the protective member 19 permeates the entire protective member 19. Here, since the protective member 19 is water-soluble as described above, when the water 10 permeates the protective member 19, a part of the protective member 19 dissolves in the water 10. This promotes the deformation of the protective member 19 and makes the protective member 19 more likely to adhere to the target object 11. However, since the water 10 supplied to the protective member 19 is in the form of a mist and is small in amount, the protective member 19 does not dissolve completely and remains in a sheet-like shape (semi-dissolved state).

[0039] 4(B) is a partial cross-sectional front view showing the object 11 and the protective member 19 after the attachment step S12. When the mist-like water 10 is supplied to the protective member 19, the deformation of the protective member 19 is promoted, and the part of the protective member 19 that is not supported by the electrodes 17 enters the gap between the electrodes 17. In addition, a part of the protective member 19 dissolves, and the protective member 19 becomes in a state where it is easy to adhere to the object 11. As a result, the protective member 19 deforms so as to conform to the surface 11a of the object 11 and the multiple electrodes 17, and the entire protective member 19 adheres closely to the object 11. As a result, the protective member 19 is attached and fixed along the unevenness of the object 11 while maintaining a generally uniform thickness.

[0040] In addition, in the pasting step S12, it is preferable to paste the protective member 19 to the object 11 while heating the protective member 19. Specifically, before, during, or after the supply of the water 10 to the protective member 19, the heat source 6 is operated to heat the holding table 4. As a result, the heat generated by the heat source 6 is conducted to the object 11 and the protective member 19 via the holding table 4, and the object 11 and the protective member 19 are heated. For example, the object 11 and the protective member 19 are heated to a temperature of 50°C or more and less than 100°C, preferably 60°C or more and 80°C or less. In particular, in order to suppress the evaporation of the water 10, it is preferable that the heating temperature is less than 100°C. By heating the protective member 19, pasting of the protective member 19 to the object 11 is promoted, and the processing time required for fixing the protective member 19 is shortened.

[0041] Also, a change in air pressure can be used to attach the protective member 19 to the object 11. Specifically, first, in a contact step S11 (see FIG. 3(A)), the object 11 and the protective member 19 are brought into contact with each other in a reduced pressure environment, that is, under a pressure lower than atmospheric pressure. For example, a reduced pressure chamber is prepared, and the protective member 19 is brought into contact with the object 11 in the reduced pressure chamber with the processing space in the reduced pressure chamber reduced. This makes it difficult for gas (air) to get between the object 11 and the protective member 19, and prevents air bubbles from interfering with the adhesion between the object 11 and the protective member 19. The pressure (absolute pressure) in the reduced pressure chamber is set, for example, to 10 Pa or more and 100 Pa or less.

[0042] After the object 11 and the protective member 19 are brought into contact with each other, the reduced pressure chamber is opened to the atmosphere, and air (atmosphere) is introduced into the reduced pressure chamber. This increases the pressure inside the reduced pressure chamber, and atmospheric pressure acts on the protective member 19. As a result, the protective member 19 is in close contact with the object 11 while deforming to conform to the irregularities of the object 11. In this manner, the protective member 19 is attached to the object 11. Note that the timing for applying atmospheric pressure to the protective member 19 may be before or after supplying water 10 (see FIG. 4(A)) to the protective member 19, or may be while water 10 is being supplied.

[0043] After the protective member 19 is attached to the object 11, a drying process (drying step) may be performed to promote drying of the object 11 and the protective member 19. For example, the object 11 and the protective member 19 are heated by the heat source 6 or the like. In addition, hot air generated by heating air may be blown onto the object 11 and the protective member 19.

[0044] In the above, the case where protective member 19 is fixed to front surface 11a side of object 11 having irregularities has been described. However, if irregularities are formed on back surface 11b side of object 11, protective member 19 may be fixed to back surface 11b side of object 11 in a similar procedure. The surface of object 11 to which protective member 19 is fixed (protected surface) is appropriately set depending on the processing applied to object 11.

[0045] As described above, by bringing the water-soluble protective member 19 into contact with the object 11 and then supplying mist-like water 10 to the protective member 19, the protective member 19 can be attached to conform to the irregularities of the object 11. This reduces the variation in thickness of the protective member 19 fixed to the object 11.

[0046] After the protective member 19 is fixed to the object 11, a predetermined processing is performed on the object 11 (processing step). As an example, a case where the laser processing is performed on the object 11 by a laser processing device 20 (see FIG. 6) will be described below.

[0047] 5 is a perspective view showing the object 11 to which the protective member 19 is fixed. When the object 11 is processed, the object 11 is supported by an annular frame 21 for ease of handling (transporting, holding, etc.) the object 11. The frame 21 is made of a metal such as SUS (stainless steel), and a circular opening 21a is provided in the center of the frame 21, penetrating the frame 21 in the thickness direction. The diameter of the opening 21a is larger than the diameter of the object 11.

[0048] A circular sheet 23 is fixed to the object 11 and the frame 21. For example, the sheet 23 may be a tape including a circular film-like substrate and an adhesive layer (glue layer) provided on the substrate. The substrate is made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate. The adhesive layer is made of an epoxy-, acrylic-, or rubber-based adhesive, an ultraviolet-curable resin, or the like. However, the sheet 23 may be a thermocompression sheet that does not include an adhesive layer and can be thermocompression bonded to the object 11 and the frame 21.

[0049] With the object 11 placed inside the opening 21a of the frame 21, the center of the sheet 23 is affixed to the back surface 11b of the object 11, and the outer periphery of the sheet 23 is affixed to the frame 21. In this way, the object 11 is supported by the frame 21 via the sheet 23. Then, with the protective member 19 fixed and supported by the frame 21, the object 11 is transported to the laser processing device 20 (see FIG. 6).

[0050] Fig. 6 is a partial cross-sectional front view showing the laser processing device 20. In Fig. 6, the X-axis direction (first horizontal direction, processing feed direction) and the Y-axis direction (second horizontal direction, indexing feed direction) are perpendicular to each other. The Z-axis direction (up-down direction, height direction, vertical direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0051] The laser processing device 20 includes a holding table (chuck table) 22 that holds the object 11. The upper surface of the holding table 22 is a flat surface that is approximately parallel to the horizontal plane (XY plane) and constitutes a holding surface 22a that holds the object 11. The holding surface 22a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve, etc. formed inside the holding table 22.

[0052] A moving unit (not shown) and a rotation drive source (not shown) are connected to the holding table 22. The moving unit is constituted by, for example, a ball screw type moving mechanism, and moves the holding table 22 in the horizontal direction (X-axis direction and Y-axis direction). The rotation drive source is constituted by a motor or the like, and rotates the holding table 22 around a rotation axis roughly parallel to the Z-axis direction. Furthermore, a plurality of clamps 24 that grip and fix the frame 21 are provided around the periphery of the holding table 22.

[0053] The laser processing apparatus 20 also includes a laser irradiation unit 26 that irradiates a laser beam. The laser irradiation unit 26 includes a laser oscillator (not shown) such as a YAG laser, a YVO4 laser, or a YLF laser, and a laser processing head 28 arranged above the holding table 22. The laser processing head 28 includes an optical system that guides a pulsed laser beam 30 emitted from the laser oscillator to the object 11. The optical system includes optical elements such as a focusing lens that focuses the laser beam 30 at a predetermined position. The object 11 is processed by being irradiated with the laser beam 30 from the laser processing head 28.

[0054] When laser processing is performed on the object 11, first, the object 11 is held by the holding table 22. For example, the object 11 is placed on the holding table 22 so that the front surface 11a side (protective member 19 side) faces upward and the back surface 11b side (sheet 23 side) faces the holding surface 22a. In addition, the frame 21 is fixed by a plurality of clamps 24. When the suction force (negative pressure) of the suction source is applied to the holding surface 22a in this state, the object 11 is sucked and held by the holding table 22 via the sheet 23.

[0055] Next, the holding table 22 is rotated to align the length direction of a predetermined street 13 with the X-axis direction (processing feed direction). Also, the position of the holding table 22 in the Y-axis direction (indexing feed direction) is adjusted so that the irradiation area of ​​the laser beam 30 is positioned on an extension line of the street 13. Furthermore, the position of the laser processing head 28 and the arrangement of the optical system are adjusted so that the focal point of the laser beam 30 is positioned at the same height as the target object 11.

[0056] Then, while irradiating the laser beam 30 from the laser processing head 28, the holding table 22 is moved along the X-axis direction. As a result, the holding table 22 and the laser beam 30 move relatively along the X-axis direction at a predetermined speed (processing feed speed), and the laser beam 30 is irradiated onto the object 11 via the protective member 19. As a result, the object 11 is processed along the streets 13.

[0057] The irradiation conditions of the laser beam 30 are set according to the content of the laser processing to be performed on the object 11. For example, the object 11 is subjected to ablation processing. In this case, the wavelength of the laser beam 30 is set so that at least a part of the laser beam 30 is absorbed by the object 11. In other words, the laser beam 30 is a laser beam that is absorbent for the object 11. Other irradiation conditions of the laser beam 30 are also appropriately set so that the object 11 is appropriately subjected to ablation processing. For example, when the object 11 is a single crystal silicon wafer, the irradiation conditions of the laser beam 30 can be set as follows. Wavelength: 355nm Average output: 2W Repetition frequency: 200kHz Machining feed speed: 400mm / s

[0058] When the laser beam 30 is irradiated onto the object 11 along the street 13, the area of ​​the object 11 irradiated with the laser beam 30 is removed by ablation. As a result, a processed groove 11c extending from the front surface 11a to the back surface 11b of the object 11 is formed linearly along the street 13. As a result, the object 11 is divided along the street 13. At this time, the laser beam 30 may be irradiated onto the object 11 through the protective member 19, or the protective member 19 may be removed along the street 13 together with the object 11.

[0059] When laser processing is performed on the object 11, processing debris 25 such as melted material (debris) of the object 11 is generated in the area irradiated with the laser beam 30. However, a protective member 19 is formed on the surface 11a side of the object 11, and the protective member 19 blocks the processing debris 25 from adhering to the surface 11a side of the object 11. This makes it possible to prevent the object 11, the device 15, and the electrodes 17 (see FIG. 1(A) etc.) from being contaminated by the processing debris 25.

[0060] Thereafter, the same procedure is repeated to form grooves 11c along the other streets 13. When grooves 11c are formed along all the streets 13, the object 11 is divided into a plurality of device chips each including a device 15 (see FIG. 1(A) etc.).

[0061] When dividing the object 11 by ablation processing, the processed grooves 11c may be formed by irradiating the laser beam 30 multiple times along each street 13. In this case, the processed grooves 11c can be formed from the front surface 11a to the back surface 11b of the object 11 while suppressing the average output of the laser beam 30. This suppresses the thermal influence on the object 11, the device 15, and the electrodes 17 (see FIG. 1(A), etc.), making processing defects less likely to occur.

[0062] However, there is no limitation on the content of the laser processing performed on the object 11. For example, a processed groove having a depth less than the thickness of the object 11 may be formed along the street 13 on the surface 11a side of the object 11. In this case, by applying an external force to the object 11 after the laser processing is completed, the object 11 can be broken starting from the processed groove and divided along the street 13. Also, the object 11 may be divided along the street 13 by cutting into the bottom of the processed groove while rotating an annular cutting blade.

[0063] When the processing of the object 11 is completed, the protective member 19 is removed from the object 11 (protective member removing step). FIG. 7 is a partial cross-sectional front view showing the cleaning device 40. For example, in the protective member removing step, the protective member 19 is removed by cleaning the object 11 with the cleaning device 40. Note that the cleaning device 40 may be mounted on the laser processing device 20 (see FIG. 6) or may be installed independently of the laser processing device 20.

[0064] The cleaning device 40 includes a spinner table 42 that holds and rotates the target object 11. The upper surface of the spinner table 42 is a flat surface that is approximately parallel to the horizontal plane (XY plane) and constitutes a holding surface 42a that holds the target object 11. The holding surface 42a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve, etc. formed inside the spinner table 42.

[0065] A rotation drive source (not shown) such as a motor that rotates the spinner table 42 around a rotation axis that is approximately parallel to the Z-axis direction is connected to the spinner table 42. In addition, a plurality of clamps 44 that grip and fix the frame 21 are provided around the periphery of the spinner table 42.

[0066] The cleaning device 40 also includes a cleaning liquid supply unit 46 that supplies a cleaning liquid. The cleaning liquid supply unit 46 includes a nozzle 48 that supplies a cleaning liquid (cleaning liquid) 50 to the object 11 held by the spinner table 42. A movement mechanism (not shown) that moves the nozzle 48 along the XY plane is connected to the nozzle 48. By operating the movement mechanism, the nozzle 48 can be positioned so as to overlap with the holding surface 42a of the spinner table 42.

[0067] There are no limitations on the material of the liquid 50 as long as it allows removal of the protective member 19. For example, a liquid (cleaning liquid) such as pure water can be used as the liquid 50. The liquid 50 may also be a mixed fluid in which a liquid such as pure water is mixed with a gas such as air.

[0068] The object 11 that has been subjected to laser processing is transported to the cleaning device 40 and held by the spinner table 42. Specifically, the object 11 is placed on the spinner table 42 so that the front surface 11a side (protective member 19 side) faces upward and the back surface 11b side (sheet 23 side) faces the holding surface 42a. In addition, the frame 21 is fixed by a plurality of clamps 44. When the suction force (negative pressure) of the suction source is applied to the holding surface 42a in this state, the object 11 is sucked and held by the spinner table 42 via the sheet 23.

[0069] Next, nozzle 48 is placed at a position overlapping with the rotation axis of spinner table 42. Then, while rotating spinner table 42, liquid 50 is supplied from nozzle 48 toward target object 11. As a result, liquid 50 is supplied to the center of target object 11, and liquid 50 flows radially toward the outer periphery of target object 11 due to the centrifugal force of the rotating target object 11. As a result, liquid 50 spreads over the entire protective member 19, and protective member 19 is removed together with machining waste 25.

[0070] As described above, since the protective member 19 is water-soluble, by supplying liquid 50 such as pure water to the protective member 19, the protective member 19 can be dissolved and easily removed from the object 11. The supply amount and supply time of the liquid 50 are appropriately set so that the protective member 19 can be dissolved and washed away.

[0071] As described above, in the method for fixing a protective member according to this embodiment, the water-soluble protective member 19 is brought into contact with the object 11, and then mist-like water 10 is supplied to the protective member 19. This makes it possible to attach the protective member 19 of a predetermined thickness to conform to the irregularities of the object 11, thereby reducing variations in the thickness of the protective member 19 caused by the irregularities of the object 11.

[0072] In the present embodiment, the water 10 is supplied in the form of a mist to the protective member 19 (see FIG. 4(A)). However, if it is possible to strictly control the amount of water 10 supplied to the protective member 19 so that a small amount of water 10 is supplied to the protective member 19 so that the protective member 19 does not completely dissolve, the water 10 does not necessarily have to be supplied in the form of a mist.

[0073] In the present embodiment, the case where the object 11 is a workpiece to be laser processed has been described. However, the object 11 may be an article other than the workpiece. For example, the protective member 19 may be fixed to a processing tool for processing the workpiece. This protects the processing tool and prevents it from being scratched or having foreign matter attached thereto.

[0074] Examples of processing tools include a cutting blade for cutting a workpiece, a grinding wheel for grinding a workpiece, and an abrasive pad for polishing a workpiece. The cutting blade includes a disk-shaped base and an annular cutting edge (processing part) formed along the outer periphery of the base. The grinding wheel includes an annular base and a plurality of grinding stones (processing part) fixed to the base. The abrasive pad includes a disk-shaped base and a disk-shaped abrasive layer (processing part) fixed to the base.

[0075] The protective member 19 is fixed to the processing tool so as to cover the base and the processing part, thereby protecting the processing tool. The processing tool is stored and transported with the protective member 19 fixed thereto. When the processing tool is to be used, the protective member 19 can be easily removed by pouring water on the protective member 19 immediately before use.

[0076] The protective member 19 may be fixed to cover the entire processing tool, or may be fixed to cover only a partial area of ​​the processing tool that particularly needs to be protected. The protective member 19 may also be fixed to an inspection device such as an ultrasonic probe.

[0077] In addition, the structures, methods, etc. according to the present embodiment can be modified as appropriate without departing from the scope of the object of the present invention.

[0078] (Embodiment 2) In the first embodiment, the protective member 19 is brought into contact with the object 11, and then mist-like water 10 is supplied to the protective member 19 to attach the protective member 19 to the object 11 (see FIGS. 3(A) and 4(A)). However, the procedure for fixing the protective member 19 to the object 11 is not limited to this.

[0079] 8 is a flow chart showing a modified example of the method for fixing the protective member. In this embodiment, water 10 is supplied to the object 11 or the protective member 19 (water supply step S21), and then the object 11 and the protective member 19 are brought into contact with each other to attach the protective member 19 to the object 11 (attaching step S22). A specific example of the method for fixing the protective member according to this embodiment will be described below. Note that the description of embodiment 1 can be referred to for matters that are omitted in this embodiment.

[0080] 9 is a partial cross-sectional front view showing the target object 11 and the protective member 19 in the water supplying step S21. In the water supplying step S21, water 10 is supplied to the target object 11 or the protective member 19, thereby adhering the water 10 to the target object 11 or the protective member 19. Here, as an example, a case will be described in which the water 10 is supplied in the form of a mist to the target object 11, thereby adhering the water 10 to the surface side (protected surface side) of the target object 11 to which the protective member 19 is fixed.

[0081] In the water supplying step S21, first, the object 11 is held by the holding table 4 of the fixing device 2. When the protective member 19 is fixed to the front surface 11a side of the object 11, the object 11 is placed on the holding table 4 so that the front surface 11a (protected surface) faces upward and the back surface 11b faces the holding surface 4a.

[0082] Next, the water supply unit 8 is positioned above the object 11. Then, while moving the holding table 4 and the water supply unit 8 relatively as necessary, the water supply unit 8 sprays mist-like water 10 toward the surface 11a side of the object 11. As a result, the water 10 is supplied over the entire surface 11a side of the object 11, and a small amount of the water 10 adheres to the surface 11a side of the object 11. The amount of water 10 supplied is adjusted so that the entire protective member 19 is not dissolved and removed by the water 10 adhered to the surface 11a side of the object 11 when the protective member 19 is brought into contact with the surface 11a side of the object 11 in a bonding step S22 described later.

[0083] 10A is a partial cross-sectional front view showing the object 11 and the protective member 19 in the attaching step S22. In the attaching step S22, the object 11 and the protective member 19 are brought into contact with each other, thereby attaching the protective member 19 to the object 11.

[0084] Specifically, a protective member 19 is prepared, and the surface (surface 11a) of the object 11 to which the water 10 is attached is brought into contact with the protective member 19. At this time, the protective member 19 is positioned so as to cover the multiple devices 15 (see FIGS. 1(A) and 1(B)) formed on the surface 11a side of the object 11.

[0085] When the protective member 19 is placed on the surface 11a side of the object 11, the water 10 adhering to the surface 11a side of the object 11 comes into contact with the protective member 19. As a result, the water 10 penetrates the protective member 19 and dissolves a part of the protective member 19, promoting the deformation of the protective member 19 and making the protective member 19 more likely to adhere to the object 11. However, because the amount of water 10 adhering to the surface 11a side of the object 11 is small, the protective member 19 does not dissolve completely and remains in a sheet-like shape (semi-dissolved state).

[0086] In the pasting step S22, the entire protective member 19 may be in a semi-molten state, or only a part of the surface side (the lower surface side in FIG. 10(A)) of the protective member 19 that contacts the object 11 may be in a semi-molten state. The range of the protective member 19 that is in a semi-molten state can be adjusted by the amount of water 10 attached to the object 11.

[0087] 10(B) is a partial cross-sectional front view showing the object 11 and protective member 19 after the attachment step S22. When water 10 comes into contact with protective member 19, the deformation of protective member 19 is promoted, and protective member 19 deforms to conform to surface 11a of object 11 and the plurality of electrodes 17. Furthermore, a portion of protective member 19 dissolves, making protective member 19 more likely to adhere to object 11. This brings the entire protective member 19 into close contact with object 11. In this way, protective member 19 is attached to object 11 along the irregularities, and is fixed to object 11.

[0088] However, in the water supply step S21, mist-like water 10 may be supplied to the protective member 19 instead of the object 11. Specifically, before the protective member 19 is brought into contact with the object 11, the mist-like water 10 is supplied to the protective member 19, and the water 10 is allowed to permeate the protective member 19. This causes the protective member 19 to be in a semi-dissolved state. In this case, the water 10 may be allowed to permeate the entire protective member 19 to cause the entire protective member 19 to be in a semi-dissolved state, or the water 10 may be allowed to permeate only a part of the surface side of the protective member 19 that contacts the object 11 (the lower surface side in FIG. 10(A)) to cause only a part of the protective member 19 to be in a semi-dissolved state. For example, the mist-like water 10 is supplied to the lower surface side of the protective member 19, and then the protective member 19 is brought into contact with the object 11. Also, the mist-like water 10 may be supplied to the upper surface side of the protective member 19, and then the protective member 19 may be turned upside down and brought into contact with the object 11.

[0089] Thereafter, the object 11 and the protective member 19 are brought into contact with each other. As a result, the protective member 19 in a semi-molten state is deformed so as to fit the surface 11a of the object 11 and the plurality of electrodes 17, and the protective member 19 is attached to the object 11 (attaching step S22).

[0090] As described above, the protective member 19 can also be attached to the object 11 by supplying water 10 to the object 11 or the protective member 19 and then bringing the object 11 and the protective member 19 into contact with each other. Note that in the attachment step S22, the protective member 19 may be brought into contact with the object 11 while being heated by the heat source 6. Alternatively, after the object 11 and the protective member 19 are brought into contact with each other in a reduced pressure environment, atmospheric pressure may be applied to the protective member 19 to make the protective member 19 adhere to the object 11.

[0091] Also, in this embodiment, the water 10 does not necessarily have to be in the form of a mist. Also, the object 11 may be an article other than the workpiece, and the protective member 19 may be fixed to a part or the whole of a processing tool, an inspection device, etc.

[0092] In addition, the structures, methods, etc. according to the present embodiment can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0093] 11 Target object (protective member formed object, workpiece) 11a Surface (first side) 11b Back side (2nd side) 11c Machining groove 13th Street (Planned division line) 15 Devices 17 Electrode (connection electrode) 19 Protective materials 21 Frame 21a opening 23 sheets 25 Processing waste 2 Fixing device (sticking device) 4 Holding table 4a Holding surface 6 Heat source (heater) 8 Water Supply Unit 10 water 20 Laser processing equipment 22 Holding table (chuck table) 22a Holding surface 24 Clamp 26 Laser irradiation unit 28 Laser processing head 30 Laser Beam 40 Cleaning Equipment 42 Spinner Table 42a Holding surface 44 Clamp 46 Cleaning solution supply unit 48 Nozzles 50 Liquid (cleaning fluid)

Claims

1. A method for fixing a water-soluble protective member to an object, comprising the steps of: a contact step of contacting the object with the protective member; After the contact step, a bonding step of supplying water to the protective member to bond the protective member to the object is also performed.

2. A method for fixing a water-soluble protective member to an object, comprising the steps of: A water supplying step of supplying water to the object; A method for fixing a protective member, comprising: after carrying out the water supply step, a bonding step of bonding the protective member to the object by contacting the surface of the object to which the water is attached with the protective member.

3. A method for fixing a water-soluble protective member to an object, comprising the steps of: a water supplying step of supplying water to the protective member; After carrying out the water supplying step, a bonding step is performed in which the protective member is bonded to the object by contacting the object with the protective member.

4. 4. The method for fixing a protective member according to claim 1, wherein the water is supplied in the form of a mist to the object or the protective member.

5. 4. The method for fixing a protective member according to claim 1, further comprising attaching the protective member to the object while heating the protective member.

6. 4. The method for fixing a protective member according to claim 1, further comprising contacting the object with the protective member in a reduced pressure environment.

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