Protective member forming device, protective member forming method, and wafer manufacturing method

Abstract

To prevent peeling of a protective member from a wafer during grinding of the wafer, and to easily peel the protective member from the wafer after grinding.SOLUTION: After a first liquid-state resin r1 having strong adhesive force is supplied by a first resin nozzle (a first resin supply unit) 83, a second liquid-state resin r2 having weak adhesive force is supplied to a central portion of the first liquid-state resin r1 by a second resin nozzle (a second supply unit) 84. The first liquid-state resin r1 and the second liquid-state resin r2 are spread over the entire one surface of a wafer W held on a holding table 31 by an elevating mechanism 40, and cured by a curing unit 60, then while a second resin R2 obtained by curing the second liquid-state resin r2 is being bonded to the central portion of the one surface of the wafer W in a circular shape, a first resin R1 obtained by curing the first liquid-state resin is bonded to the outside of the second resin R2.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a protective member forming apparatus and a protective member forming method for forming a protective member over the entire surface of one side of a wafer. [Background technology]

[0002] For example, wafers used in the manufacture of semiconductor devices such as ICs and LSIs used in electronic devices are obtained by cutting a single crystal ingot of silicon or the like with a cutting device such as a blade saw or a wire saw to produce sliced ​​wafers, and then flattening both surfaces of the sliced ​​wafers with a grinding device or a polishing device. Devices such as ICs and LSIs are then formed on the front surface of the wafer with both surfaces flattened in this way, the back surface of the wafer on which these devices are formed is ground to thin the wafer to a predetermined thickness, and the thinned wafer is then cut with a dicing saw or the like to separate into individual devices.

[0003] Sliced ​​wafers cut from an ingot have warpage and undulations on the surface of both sides due to differences in the magnitude of processing strain that occurs on both sides during cutting using a cutting device such as a blade saw. For this reason, a processing method is practiced in which a protective member such as an ultraviolet-curable resin is formed on one side of the sliced ​​wafer to flatten that side, the other side of the sliced ​​wafer is ground while the flat side of the protective member is held on the holding surface of a chuck table to flatten the other side, and then the protective member is peeled off from the sliced ​​wafer. Patent Documents 1 to 3, for example, propose protective member forming devices for forming a protective member on one side of a sliced ​​wafer.

[0004] In the protective member forming device, a liquid resin is spread over the entire surface of one side of a sliced ​​wafer (hereinafter simply referred to as "wafer") and then hardened to form a protective member. When spreading the liquid resin over the entire surface of one side of the wafer, a sheet is placed on an extension table, the liquid resin is dripped onto the sheet, a holding table placed above the extension table is lowered together with the wafer held on it to a predetermined height position, and the liquid resin on the sheet is pressed by the wafer to spread the liquid resin. If the liquid resin is an ultraviolet-curable resin, the ultraviolet-curable resin is irradiated with ultraviolet light to harden the ultraviolet-curable resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-192473 [Patent Document 2] Japanese Patent Application Publication No. 2017-079291 [Patent Document 3] Japanese Patent Application Publication No. 2019-029543 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when a wafer having a protective member formed over the entire surface of one side is held on a chuck table with the protective member facing downward and the other side of the wafer is ground with a grinding wheel, the protective member peels off from the outer periphery of the wafer, causing the outer periphery of the wafer to become thinner.

[0007] One possible solution to the above problem is to increase the adhesive strength of the protective member. However, if the adhesive strength of the protective member is increased, it becomes difficult to peel the protective member from the wafer after grinding. If the protective member is forcibly peeled off, problems arise in that part of the protective member remains on the wafer or the wafer is damaged.

[0008] The present invention has been made in consideration of the above problems, and its object is to provide a protective member forming device and a protective member forming method that can prevent the protective member from peeling off from the wafer during wafer grinding processing, and that can easily peel the protective member off from the wafer after grinding processing. [Means for solving the problem]

[0009] To achieve the above object, the first invention comprises an expansion table that expands the dropped liquid resin; a control unit that adheres the first resin to the center of the first liquid resin by the second supply unit, and the lifting mechanism that lifts and lowers the holding table and the extension table in a circular shape to the center of the one side of the wafer, and adheres the first resin, which is the hardened first liquid resin, to the outside of the second resin.

[0010] The second invention is a protective member forming method for forming a protective member by spreading and hardening a liquid resin over the entire surface of one side of a wafer using the protective member forming apparatus of the first invention, and is characterized in that the protective member is formed over the entire surface of one side of the wafer through the following steps: a first liquid resin supplying process for supplying the first liquid resin to the extension table side; a second liquid resin supplying process for supplying the second liquid resin to the central portion of the first liquid resin; an expansion process for bringing the extension table and the holding table closer together in the vertical direction to spread the first liquid resin and the second liquid resin over the entire surface of one side of the wafer; and a hardening process for hardening the first liquid resin and the second liquid resin. [Effects of the Invention]

[0011] According to the protective member forming method of the second invention, which is carried out using the protective member forming apparatus of the first invention, the protective member is composed of a first resin with strong adhesive strength and a second resin with weaker adhesive strength than the first resin, and the first resin with strong adhesive strength is adhered to the outer periphery of one side of the wafer, and the second resin with weaker adhesive strength is adhered inside it, which prevents the first resin with strong adhesive strength from peeling off from the outer periphery of the wafer during wafer grinding, and after grinding, the protective member, which has the second resin adhered to most of the wafer except for the outer periphery, can be easily peeled off from the wafer. Therefore, problems such as parts of the protective member remaining on the wafer or damage to the wafer do not occur. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view of a protective member forming apparatus according to the present invention; [Figure 2] 1 is a vertical cross-sectional view of a main part (an extension table and a holding table portion) of a protective member forming device according to the present invention. [Figure 3] 3 is a vertical cross-sectional view showing a sheet arranging step in the method for forming a protection member according to the first embodiment of the present invention. FIG. [Figure 4] FIG. 3 is a vertical cross-sectional view showing a first liquid resin supplying step in the method for forming a protection member according to the first embodiment of the present invention. [Figure 5] 5(a) and 5(b) are longitudinal cross-sectional views showing a second liquid resin supplying step in the method for forming a protection member according to the first embodiment of the present invention. [Figure 6] 3 is a vertical cross-sectional view showing an expansion step in the method for forming a protective member according to the first embodiment of the present invention. FIG. [Figure 7] 3 is a vertical cross-sectional view showing a leaving step in the method for forming a protective member according to the first embodiment of the present invention. FIG. [Figure 8] 3 is a vertical cross-sectional view showing a curing step in the method for forming a protective member according to the first embodiment of the present invention. FIG. [Figure 9] FIG. 9 is an enlarged detailed view of part A in FIG. 8. [Figure 10] 10 is a vertical cross-sectional view showing a state in which a surface of a wafer having a protective member formed on one side is being ground. FIG. [Figure 11] 10(a) to 10(c) are side cross-sectional views showing a method for peeling off the protective member. [Figure 12] FIG. 10 is a vertical cross-sectional view showing a state in which one surface of the wafer from which the protective member has been peeled off is being ground. [Figure 13] 10(a) and 10(b) are vertical cross-sectional views showing a second resin supplying step in a method for forming a protection member according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a vertical cross-sectional view showing a first resin supplying step in a method for forming a protection member according to a second embodiment of the present invention. [Figure 15] 10(a) and 10(b) are vertical cross-sectional views showing a second resin supplying step in a method for forming a protection member according to a second embodiment of the present invention. [Figure 16] 10 is a vertical cross-sectional view showing an expansion step in a method for forming a protective member according to a second embodiment of the present invention. FIG. [Figure 17] FIG. 10 is a vertical cross-sectional view showing a leaving step in a method for forming a protective member according to a second embodiment of the present invention. [Figure 18] FIG. 10 is a vertical cross-sectional view showing a curing step in a method for forming a protective member according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Configuration of protective member forming device] First, the configuration of the protective member forming device according to the first aspect of the present invention will be described with reference to Fig. 1. In the following description, the directions of the arrows shown in Fig. 1 will be referred to as the X-axis (left-right direction), the Y-axis (front-rear direction), and the Z-axis (up-down direction), respectively.

[0014] The protective member forming apparatus 1 shown in FIG. 1 is an apparatus for forming a protective member on one surface (the lower surface in FIG. 1) of a disk-shaped wafer W, and includes a housing 100 and a cassette storage unit 110 arranged along the X-axis direction. Here, the cassette storage unit 110 stores a first cassette 111 and a second cassette 112 along the Y-axis direction. One of the first cassettes 111 stores a plurality of wafers W before the formation of a protective member P (see FIGS. 8 to 11), which will be described later, and the other, second cassette 112 stores a plurality of wafers W on which the protective member P has been formed. The wafers W are disk-shaped sliced ​​wafers cut from a cylindrical ingot of single crystal silicon or the like.

[0015] The housing 100 also accommodates, in order from the −X-axis direction (left side), components such as a first transport means 10, a second transport means 20, a temporary placement table 2, a sheet cutting table 4, a wafer holder 30, a lifting mechanism 40, an extension table 50, a curing unit 60, two dispensers, a first dispenser 71 and a second dispenser 72, a sheet transport unit 7, and a control unit 90. The configuration of each component will be described below in order.

[0016] (First conveying means) The first transport means 10 functions to remove wafers W from the first cassette 111 and transport them to the temporary placement table 2, as well as to receive wafers W with protective members P formed thereon from the sheet cutting table 4 and store them in the second cassette 112, and is equipped with a robot hand 12 installed on a base 11 and a Y-axis movement mechanism 13 that moves the base 11 together with the robot hand 12 in the Y-axis direction.

[0017] Here, the Y-axis movement mechanism 13 is composed of a pair of guide rails 14 arranged parallel to each other along the Y-axis direction, a rotatable ball screw 15 arranged along the Y-axis direction between these guide rails 14, and a motor 16 for rotating the ball screw 15 forward and backward, and the ball screw 15 is threadedly inserted into a nut member (not shown) that protrudes from the underside of the base 11. Therefore, when the motor 16 is started to rotate the ball screw 15 forward and backward, the base 11, on which the nut member (not shown) protrudes and into which the ball screw 15 threads, moves along the Y-axis direction together with the robot hand 12.

[0018] (Second conveying means) The second transport means 20 receives the wafer W from the temporary placement table 2 and transports it to the wafer holding section 30, and also receives the wafer W on which the protective member P is formed from the extension table 50 and transports it to the sheet cutting table 4.It is equipped with a robot hand 22 installed on a base 21 and an X-axis movement mechanism 23 that moves the base 21 together with the robot hand 22 in the X-axis direction.

[0019] Here, the X-axis movement mechanism 23 is composed of a pair of guide rails 24 arranged parallel to each other along the X-axis direction, a rotatable ball screw 25 arranged between these guide rails 24 along the X-axis direction, and a motor (not shown) for rotating the ball screw 25 forward and backward, and the ball screw 25 is threadedly inserted into a nut member (not shown) protruding from the underside of the base 21. Therefore, when the motor (not shown) is started to rotate the ball screw 25 forward and backward, the base 21, on which the nut member (not shown) protruding and into which the ball screw 25 is threadedly inserted, moves along the X-axis direction together with the robot hand 22.

[0020] (Temporary table) The temporary placement table 2 is used to temporarily place the wafer W taken out from the first cassette 111 by the robot hand 12 of the first transport means 10, and the center position and orientation of the wafer W temporarily placed on the temporary placement table 2 are optically detected by the wafer detection unit 3.

[0021] (Sheet cutting table) The sheet cutting table 4 is arranged below the temporary placement table 2, and is used to place the wafer W on which the protective member P is formed. The sheet S attached to the wafer W is cut into a circle along the outer periphery of the wafer W by the sheet cutter 5.

[0022] (Wafer holder) The wafer holder 30 includes a disk-shaped holding table 31, the lower surface of which constitutes a holding surface. As shown in Fig. 2, a porous disk-shaped porous member 31A is incorporated in the lower center of the holding table 31, and this porous member 31A is selectively connected to a suction source 33 such as a vacuum pump via a pipe 32. The pipe 32 is provided with an on-off valve V1.

[0023] (Lifting mechanism) The lifting mechanism 40 is a mechanism for raising and lowering the holding table 31 of the wafer holding part 30 together with the wafer W held thereon by suction in the Z-axis direction, and is installed on a column 130 that stands vertically on the base 120. That is, the lifting mechanism 40 includes a pair of guide rails 41 that are attached vertically and parallel to each other to the end face of the column 130 in the +X-axis direction, a lifting plate 42 that moves up and down in the Z-axis direction along these guide rails 41, a rotatable ball screw 43 that is vertically arranged between the pair of guide rails 41, a motor 44 that rotates the ball screw 43 forward and backward, and an encoder 45 that detects the number of rotations, rotation speed, rotation direction, etc. of the motor 44.

[0024] The holding table 31 of the wafer holding unit 30 is attached to the lift plate 42. Here, the encoder 45 constitutes a position detection unit that detects the height position of the holding table 31 based on the rotation speed and direction of the motor 44, and this encoder 45 and motor 44 are electrically connected to the control unit 90. Although not shown, a nut member is attached to the back surface of the lift plate 42, and a ball screw 43 is threadedly inserted into this nut member.

[0025] Therefore, when the motor 44 is started to rotate the ball screw 43 forward and backward, the lifting plate 42, to which a nut member (not shown) that screws onto the ball screw 43 is attached, moves up and down in the Z-axis direction along the pair of guide rails 41 together with the wafer holding portion 30 and the wafer W held by suction on the holding table 31 of the wafer holding portion 30, and the height position of the holding table 31 is detected by the encoder 45, which is a position detection unit.

[0026] (extension table) The extension table 50 installed on the base 120 is a disk-shaped member made of a light-transmitting material such as quartz glass, and its upper surface forms a flat holding surface on which the sheet S is placed. A ring-shaped suction groove 50a is formed around the periphery of the holding surface of the extension table 50.

[0027] (curing unit) The curing unit 60 is disposed below the extension table 50, and as will be described later, irradiates ultraviolet (UV) rays onto a first liquid resin r1 (see FIG. 4) and a second liquid resin r2 (see FIG. 5), which are ultraviolet curable resins supplied onto a sheet S placed on the extension table 50, thereby curing the first liquid resin r1 and the second liquid resin r2. As shown in FIG. 2, the curing unit 60 includes a case 61 whose upper surface is closed by the extension table 50. Here, the case 61 includes a side wall 61A and a bottom plate 61B, and a space defined by these side wall 61A, bottom plate 61B, and extension table 50 contains a plurality of UV lamps 62 that irradiate ultraviolet rays toward the first liquid resin r1 and the second liquid resin r2.

[0028] (Dispenser) The first dispenser 71 and the second dispenser 72 supply a predetermined amount of a first liquid resin r1 and a second liquid resin r2 stored in a first resin tank 81 and a second resin tank 82, respectively, installed in the base 120, onto the upper surface of the sheet S held on the upper surface of the extension table 50. The first dispenser 71 and the second dispenser 72 are connected to the first resin tank 81 and the second resin tank 82, respectively, via resin piping (not shown), and are also connected to a first resin nozzle 83 and a second resin nozzle 84, respectively. The first dispenser 71, the first resin tank 81, the first resin nozzle 83, etc. constitute a first supply unit that supplies the first liquid resin r1 to the sheet S, and the second dispenser 72, the second resin tank 82, the second resin nozzle 84, etc. constitute a second supply unit that supplies the second liquid resin r2 to the sheet S.

[0029] (sheet transport section) The sheet conveying unit 7 pulls out the sheet S from the sheet roll R on which the sheet S is wound in a roll shape and conveys it to the extension table 50. The sheet conveying unit 7 includes a clamp unit 8a attached to the side of an arm 8 that is movable in the X-axis direction. Therefore, when the arm 8 moves in the -X-axis direction with the clamp unit 8a gripping the end of the sheet S wound around the sheet roll R, the sheet S is pulled out from the sheet roll R and held on the upper surface of the extension table 50. The sheet S held on the extension table 50 is then cut to an appropriate length. Note that the sheet S is made of a film such as polyethylene terephthalate (PET), which is a light-transmitting material that transmits ultraviolet light. Here, if the liquid resin is a thermosetting type, the sheet S does not need to be a light-transmitting material.

[0030] (Control unit) The control unit 90 includes a CPU (Central Processing Unit) that performs arithmetic processing according to a control program, and storage units such as a ROM (Read Only Memory) and a RAM (Random Access Memory). In particular, in this embodiment, the control unit 90 controls each component to supply a first liquid resin r1 and a second liquid resin r2 onto the sheet S, spread the first liquid resin r1 and the second liquid resin r2 onto one surface of the wafer W, and then harden the spread first liquid resin r1 and the second liquid resin r2 to form a protective member P on one surface of the wafer W, as will be described later.

[0031] [Protective member forming method] Next, a first embodiment of a method for forming a protective member according to a second aspect of the present invention, which is carried out using the protective member forming apparatus 1 configured as above, will be described below with reference to FIGS.

[0032] First Embodiment The protective member forming method according to the first embodiment includes the steps of: 1) Sheet placement process 2) First liquid resin supply process 3) Second liquid resin supply process 4) Expansion process 5) Leaving process 6) Curing process By carrying out the above steps in this order, a protective member P is formed on one surface of the wafer W. Each step will be described below.

[0033] 1) Sheet placement process: In the sheet placement process, as shown in Fig. 3, a thin, rectangular, transparent sheet S is supplied onto an extension table 50 provided on the upper surface of a case 61 of a curing unit 60. That is, in a state in which one end of the sheet S wound around a sheet roll R in the sheet conveying section 7 shown in Fig. 1 is gripped by a clamp portion 8a of an arm 8, the arm 8 moves in the -X-axis direction in Fig. 1, whereby the sheet S is supplied and set on the extension table 50.

[0034] 2) First liquid resin supply process: The first liquid resin supplying step is a step in which the first liquid resin r1 stored in the first resin tank 81 shown in Fig. 1 is supplied to the first resin nozzle 83 by the first dispenser 71, and the first liquid resin r1 is dripped from this first resin nozzle 83 toward the center of the sheet S, as shown in Fig. 4. When the first liquid resin r1 is dripped onto the center of the sheet S in this manner, the dripped first liquid resin r1 spreads in a circular shape with a small diameter at the center of the sheet S, creating a concave depression in the central portion.

[0035] 3) Second liquid resin supply process: The second liquid resin supplying step is a step in which the second liquid resin r2 contained in the second resin tank 82 shown in FIG. 1 is supplied to the second resin nozzle 84 by the second dispenser 72 shown in FIG. 1, and as shown in FIG. 5(a), the second liquid resin r2 is dropped from the first nozzle 84a of the second resin nozzle 84 toward the center of the sheet S, and a small amount of the second liquid resin r2 is supplied from the nozzle 30b opening upward to the center of one side (the lower surface in FIG. 5(a)) of the wafer W held by suction on the lower surface of the holding table 31. Note that the second liquid resin r2 has a weaker adhesive strength than the first liquid resin r1. In addition, although ultraviolet-curable resins are used as the first liquid resin r1 and the second liquid resin r2 in this embodiment, other liquid resins such as thermosetting resins may also be used.

[0036] In this second liquid resin supply process, as shown in Figure 5(b), a predetermined amount of second liquid resin r2 is dripped onto the center of the sheet S placed on the extension table 50, overlapping the center of the first liquid resin r1 that has already been dripped, and a small amount of second liquid resin r2 is supplied to the center of one side (the bottom surface in Figure 5(b)) of the wafer W held on the holding table 31.

[0037] As described above, when the second liquid resin r2 is dropped onto the sheet S on top of the central portion of the first liquid resin r1 that has already been dropped, the central portions of the first liquid resin r1 and the second liquid resin r2 become depressed. However, in the expansion process described below, the shortage of the second liquid resin r2 in the depressed portions in the central portions of the first liquid resin r1 and the second liquid resin r2 on the sheet S is replenished by a small amount of the second liquid resin r2 that has adhered to the center of one side (the bottom surface) of the wafer W.

[0038] 4) Expansion process: As shown in Figure 6, the expansion process is a process of spreading out the first liquid resin r1 and the second liquid resin r2 dripped onto the sheet S in the first liquid resin supply process and the second liquid resin supply process.In this expansion process, the on-off valve V1 opens and the porous member 31A of the holding table 31 is connected to the suction source 33 via the piping 32, generating a negative pressure in the porous member 31A.The wafer W is attracted by this negative pressure and held by suction on the holding surface of the holding table 31 (the lower surface of the porous member 31A).

[0039] When the holding table 31 is lowered by the lifting mechanism 40 from the above state, the wafer W held by suction on the underside of the holding table 31 presses the first liquid resin r1 and the second liquid resin r2 on the sheet S, spreading the first liquid resin r1 and the second liquid resin r2 to a uniform thickness. Note that in this spreading step, as described above, the second liquid resin r2 dripped onto the center of the sheet S in the second liquid resin supply step, causing a depression in the central portion, is replenished by a small amount of the second liquid resin r2 supplied to and adhering to the center of the wafer W.

[0040] As described above, when the first liquid resin r1 on the sheet S and the second liquid resin r2 layered on top of it are spread out by the descending wafer W, the first liquid resin r1 and the second liquid resin r2 spread out in a circular shape with a uniform thickness, with the first liquid resin r1, which has strong adhesive strength, occupying the outer periphery of this circle in a ring shape, and the second liquid resin r2, which has weak adhesive strength, being positioned inside the first liquid resin r1 in a circular shape.

[0041] 5) Leaving process: In the leaving step, when the first liquid resin r1 and the second liquid resin r2 are spread by one surface (bottom surface) of the wafer W in the previous spreading step, as shown in Fig. 7, the on-off valve V1 is opened to cut off the connection between the porous member 31A and the suction source 33, releasing the suction holding force of the holding table 31, and the lifting mechanism 40 raises the holding table 31 to separate it from the wafer W. Then, the load acting on the first liquid resin r1 and the second liquid resin r2 that have been spread into a circular shape by one surface (bottom surface) of the wafer W becomes the weight of the wafer W alone, and the first liquid resin r1 and the second liquid resin r2 stop flowing, maintaining the state in which they are spread out to the outer periphery of the wafer W.

[0042] 6)Curing process: In the curing step, once the first liquid resin r1 and the second liquid resin r2, which have been spread into a circular shape by one surface of the wafer W in the previous leaving step, stop flowing and support the wafer W, the multiple UV lamps 62 in the case 61 are turned on, as shown in Fig. 8. Then, ultraviolet (UV) rays emitted upward from each UV lamp 62 pass through the transparent extension table 50 and sheet S and are irradiated onto the first liquid resin r1 and the second liquid resin r2, which are cured by the UV irradiation to become the first resin R1 and the second resin R2, and a protective member P composed of the first resin R1 and the second resin R2 is formed on one surface of the wafer W (the underside in Fig. 8).

[0043] After the protective member P is formed on one side of the wafer W through the above steps, the other side of the wafer W (the side on which the protective member P is not formed) is ground by a grinding wheel 125b shown in FIG. 10 of a grinding device. In FIG. 10, reference numeral 123 denotes a spindle that is rotated by a spindle motor (not shown), and a disk-shaped mount is attached to the lower end of the spindle 123. A grinding wheel 125 is detachably attached to the lower surface of the mount 124. The grinding wheel 125 is configured by attaching a plurality of grinding wheels 125b arranged in an annular shape to the lower surface of a disk-shaped base 125a. The grinding unit including the grinding wheel 125 can be raised and lowered vertically by an elevator mechanism 140.

[0044] When grinding the other surface (the surface on which the protective member P is not formed) of a wafer W having a protective member P formed on one surface, the wafer W is suction-held on the holding surface of a chuck table 200 with the flat protective member P facing downward, as shown in Fig. 10. A porous member 100A having a circular disc shape is incorporated in the upper center of the chuck table 200. The porous member 200A is connected to a suction source 202 via a pipe 201, and the pipe 201 is provided with an on-off valve V2.

[0045] Therefore, when the on-off valve V2 is opened to connect the porous member 200A to the suction source 202, a negative pressure is generated in the porous member 200A, and the wafer W is attracted by this negative pressure and held by suction onto the holding surface (upper surface) of the chuck table 200 with the sheet S (protective member P) facing downward. The chuck table 200 is rotatable about a vertical rotation axis CL1, and is driven to rotate at a predetermined speed in the direction of the arrow in FIG. 10 by a drive source (not shown).

[0046] In addition, the grinding wheel 125 is driven to rotate at a predetermined speed in the direction of the arrow shown (the same direction as the rotation direction of the chuck table 200) around the rotation axis CL2 of the spindle 123 by a spindle motor not shown, and is raised and lowered vertically by the lifting mechanism 140.

[0047] Thus, in grinding the wafer W, the chuck table 200 is rotated together with the wafer W by a rotation mechanism (not shown) in the direction of the arrow shown at a predetermined speed around the rotation axis CL1, and the grinding wheel 125 is positioned so that the circumscribed circle of the grinding stone 125b passes through the center of the wafer W, and the grinding wheel 125 is rotated at a predetermined speed around the rotation axis CL2 by a spindle motor (not shown).

[0048] When the grinding wheel 125 is lowered by the lifting mechanism 140 by a predetermined amount of grinding from the above state, the other surface of the wafer W (the upper surface in FIG. 10) on which the protective member P is not formed is ground by the grinding stone 125b. As a result, any warping or waviness remaining on the other surface of the wafer W is removed, and the other surface (the upper surface in FIG. 10) of the wafer W is made into a flat plane. During grinding of the wafer W, grinding water (pure water) is supplied to the contact point (processing point) between the wafer W and the grinding stone 125b, so that frictional heat generated at the processing point is removed by the grinding water, thereby suppressing a temperature rise at the processing point, and grinding chips generated by grinding are washed away by the grinding water.

[0049] In the above-described grinding process of the wafer W, the protective member P is composed of a first resin R1 with a strong adhesive force and a second resin R2 with a weaker adhesive force than the first resin R1, and the first resin R1 with a strong adhesive force is adhered to the outer periphery of one side of the wafer W, and the second resin R2 with a weaker adhesive force is adhered inside it, thereby preventing the first resin R1 with a strong adhesive force from peeling off from the outer periphery of the wafer W during the grinding process of the wafer W.

[0050] Once the other surface of the wafer W has been ground to a flat surface as described above, the protective member P formed on one surface of the wafer W is peeled off from the wafer W together with the sheet S as follows.

[0051] That is, in this embodiment, a method for peeling the protective member P together with the sheet S from the wafer W is adopted in which a force is applied in a direction in which the protective member P is easily peeled off. That is, as shown in Fig. 11(a), an edge of the sheet S of the protective member P formed on one surface (the bottom surface in Fig. 11(a)) of the wafer W whose other surface has been ground by grinding is gripped by a clamper 150 as shown in Fig. 1(b), and the clamper 150 is pulled in the direction of the arrow (diagonally downward) in which the protective member P is easily peeled off, thereby peeling the protective member P from the wafer W. Fig. 11(c) shows the wafer W from which the protective member P has been peeled off, but warping and waviness still remain on the one surface of the wafer W from which the protective member P has been peeled off (the bottom surface in Fig. 11(c)).

[0052] In this embodiment, the protective member P is composed of a first resin R1 with strong adhesive strength and a second resin R2 with weaker adhesive strength than the first resin R1, and the first resin R1 with strong adhesive strength is adhered to the outer periphery of one side of the wafer W, and the second resin R2 with weaker adhesive strength is adhered to the inside thereof.Therefore, the protective member P, which has the second resin R2 adhered to most of the wafer W except for the outer periphery, can be easily peeled off from the wafer W together with the sheet S.

[0053] Once the protective material P has been peeled off from the wafer W together with the sheet S in the above manner, the wafer W is suction-held on the holding surface of the chuck table 200 with the other flat surface of the wafer W, which has already been ground, facing downward, as shown in Fig. 12. Then, the surface of the wafer W from which the protective material P has been peeled off is ground by the grinding wheel 125b in the same manner as described above.

[0054] That is, as shown in FIG. 12, the chuck table 200 is rotated together with the wafer W at a predetermined speed in the direction of the arrow shown by a rotation mechanism not shown, around the rotation axis CL1, and the grinding wheel 125 is positioned so that the circumscribed circle of the grinding stone 125bb passes through the center of the wafer W, and the grinding wheel 125 is rotated at a predetermined speed around the rotation axis CL2 by a spindle motor not shown.

[0055] Then, when the grinding wheel 125 is lowered by the lifting mechanism 140 by a predetermined amount of grinding from the above state, one surface of the wafer W on which the protective member P was formed (the upper surface in FIG. 12) is ground by the grinding stone 125b. As a result, any warping or waviness remaining on one surface of the wafer W is removed, and both surfaces of the wafer W are ground to form a flat surface. Note that during this grinding, grinding water (pure water) is supplied to the contact point (processing point) between the wafer W and the grinding stone 125b, so that frictional heat generated at the processing point is removed by the grinding water, thereby suppressing a temperature rise at the processing point, and grinding debris generated by grinding is washed away by the grinding water.

[0056] As is clear from the above description, in this embodiment, the protective member P is composed of a first resin R1 having a strong adhesive force and a second resin R2 having a weaker adhesive force than the first resin R1, and the first resin R1 having a strong adhesive force is adhered to the outer periphery of one surface of the wafer W, and the second resin R2 having a weaker adhesive force is adhered to the inner side thereof. This prevents the first resin R1 having a strong adhesive force from peeling off from the outer periphery of the wafer W during grinding of the wafer W, and after grinding, the protective member P, to which the second resin R2 is adhered to most of the wafer W except for the outer periphery, can be easily peeled off from the wafer W. Therefore, problems such as parts of the protective member P remaining on the wafer W or damage to the wafer W do not occur.

[0057] Second Embodiment Next, a method for forming a protective member according to a second embodiment of the present invention will be described with reference to FIGS.

[0058] The protective member forming method according to the present embodiment includes the steps of: 1) First second liquid resin supply process 2) First liquid resin supply process 3) Second liquid resin supply process 4) Expansion process 5) Leaving process 6) Curing process This method forms a protective member P on one side of the wafer W by performing the above steps sequentially in this order, and since the sheet S is not used as in the first embodiment, the second liquid resin r2, which has weak adhesive strength, is dropped onto the extension table 50, the first liquid resin r1 is dropped on top of that, and the second liquid resin r2 is further dropped on top of that. Each step will be explained below.

[0059] 1) First second liquid resin supply process: The second liquid resin supply process is a process in which second liquid resin r2 with weak adhesive strength is dripped from the first nozzle 84a of the second resin nozzle 84 toward the center of the extension table 50, as shown in Figure 13(a), and a small amount of second liquid resin r2 is supplied from nozzle 30b opening upward to the center of one side (the bottom side in Figure 13(a)) of the wafer W held by suction on the bottom surface of the holding table 31.

[0060] 2) First liquid resin supply process: The first liquid resin supplying step is a step of dripping a first liquid resin r1 having a strong adhesive force from a first resin nozzle 83 onto a second liquid resin r2 on the extension table 50, as shown in FIG.

[0061] 3) Second liquid resin supply process: As shown in Figure 15(a), the second liquid resin supply process is a process in which second liquid resin r2 is dripped from the first nozzle 84a of the second resin nozzle 84 onto the first liquid resin r1 that has been dripped onto the second liquid resin r2 on the extension table 50, and a small amount of second liquid resin r2 is supplied from the nozzle 30b that opens upward to the center of one side (the bottom side in Figure 15(a)) of the wafer W that is held by suction on the bottom surface of the holding table 31.

[0062] 15(b), in this second liquid resin supplying step, a predetermined amount of second liquid resin r2 is dripped onto the extension table 50, overlapping the second liquid resin r2 and the first liquid resin r1 that have already been dripped onto the extension table 50. Note that if a small amount of second liquid resin r2 was not supplied to the center of one side of the wafer W (the lower side in FIG. 13(a)) during the first second liquid resin supplying step, a small amount of second liquid resin r2 may be supplied in this step.

[0063] 4) Expansion process: As shown in Figure 16, the expansion process is a process of pushing out the second liquid resin r2, the first liquid resin r1, and the second liquid resin r2 that are dripped onto the expansion table 50 in the second liquid resin supply process and the first liquid resin supply and second liquid resin supply process to form a three-layer structure.In this expansion process, the on-off valve V1 opens and the porous member 31A of the holding table 31 is connected to the suction source 33 via the piping 32, generating a negative pressure in the porous member 31A, and the wafer W is attracted by this negative pressure and held by suction on the holding surface of the holding table 31 (the underside of the porous member 31A).

[0064] When the holding table 31 is lowered by the lifting mechanism 40 from the above state, the wafer W held by suction on the underside of the holding table 31 presses the second liquid resin r2, the first liquid resin r1, and the second liquid resin r2 that make up the three-layer structure on the extension table 50, the upper and lower second liquid resins r2 are connected, and the second liquid resin r2 is spread out in the central part of the wafer W, and the first liquid resin r1 is spread out in a ring shape by the second liquid resin r2, and the second liquid resin r2 is spread out below the first liquid resin r1. In other words, the outer periphery of the wafer W has a two-layer structure in which the second liquid resin r2 is disposed below the first liquid resin r1.

[0065] 5) Leaving process: In the leaving step, when the first liquid resin r1 and the second liquid resin r2 are spread by one surface (bottom surface) of the wafer W in the previous spreading step, as shown in Fig. 17, the on-off valve V1 is opened to cut off the connection between the porous member 31A and the suction source 33, releasing the suction holding force of the holding table 31, and the lifting mechanism 40 raises the holding table 31 to separate it from the wafer W. Then, the load acting on the first liquid resin r1 and the second liquid resin r2 that have been spread into a circular shape by one surface (bottom surface) of the wafer W becomes the weight of the wafer W alone, and the first liquid resin r1 and the second liquid resin r2 stop flowing, maintaining the state in which they are spread out to the outer periphery of the wafer W.

[0066] 6)Curing process: In the curing step, once the first liquid resin r1 and the second liquid resin r2, which have been spread into a circular shape by one surface of the wafer W in the previous leaving step, stop flowing and support the wafer W, the multiple UV lamps 62 in the case 61 are turned on, as shown in Fig. 18. Then, ultraviolet (UV) rays emitted upward from each UV lamp 62 pass through the transparent extension table 50 and are irradiated onto the first liquid resin r1 and the second liquid resin r2, which are cured by the UV irradiation to become the first resin R1 and the second resin R2, and a protective member P composed of the first resin R1 and the second resin R2 is formed on one surface of the wafer W (the bottom surface in Fig. 18).

[0067] As described above, in the protective member forming method according to this embodiment, the protective member P is composed of a first resin R1 having a strong adhesive force and a second resin R2 having a weaker adhesive force than the first resin R1. The first resin R1 having a strong adhesive force is adhered to the outer periphery of one surface of the wafer W, and the second resin R2 having a weaker adhesive force is adhered to the inner side of the first resin R1. This prevents the protective member P from peeling off the wafer W during grinding and allows the protective member P to be easily peeled off the wafer W, similar to the first embodiment. Since this embodiment does not use a sheet S, the sheet conveying unit 7 in the protective member forming apparatus 1 shown in FIG. 1 can be omitted, and the sheet placement process in the protective member forming method can also be eliminated. Alternatively, the sheet S may be used to easily peel the protective member P from the wafer W. Furthermore, a protective member P similar to that of the first embodiment can be formed by adjusting the supply amounts of the first liquid resin r1 and the second liquid resin r2.

[0068] It should be noted that the present invention is not limited to the application of the above-described embodiments, and various modifications are possible within the scope of the claims and the technical ideas described in the specification and drawings. [Explanation of symbols]

[0069] 1: protective member forming device, 2: temporary placement table, 3: wafer detection unit, 4: Sheet cutting table, 5: Sheet cutter, 7: Sheet transport unit, 8: Arm, 8a: clamping unit, 10: first conveying means, 11: base, 12: robot hand, 13: Y-axis movement mechanism, 14: guide rail, 15: ball screw, 16: motor, 20: Second transport means, 21: Base, 22: Robot and hand, 23: X-axis movement mechanism, 24: guide rail, 25: ball screw, 30: wafer holder, 31: wafer holding table, 31A: porous member, 32: piping, 40: lifting mechanism, 41: Guide rail, 42: Lifting plate, 43: Ball screw, 44: Motor, 45: Encoder, 50: Extension table, 50a: Suction groove, 60: Hardening unit, 61: Case, 61A: Side wall, 61B: Bottom plate, 62: UV lamp, 71: first dispenser, 72: second dispenser, 81: first resin tank, 82: second resin tank, 83: first resin nozzle, 83a: first nozzle, 84: second resin nozzle, 84a: second nozzle, 90: control unit, 100: housing, 110: cassette storage section, 111: first cassette, 112: second cassette, 120: base, 123: spindle, 124: mount, 125: grinding wheel, 125a: base, 125b: grinding wheel, 130: column, 140: lifting mechanism, 150: clamper, 200: chuck table, 200A: porous member, 201: piping, 202: suction source, CL1: Rotation axis of the chuck table, CL2: Rotation axis of the spindle, P: Protective member, R: Sheet roll, R1: First resin, R2: Second resin, r1: First liquid resin, r2: Second liquid resin, S sheet: V1, V2: On-off valve, W: Wafer

Claims

1. an expansion table that expands the dripped liquid resin; a holding table disposed above and facing the extension table; a liquid resin supply unit that supplies liquid resin to the extension table side; a lifting mechanism that lifts and lowers the holding table and the extension table relatively in a vertical direction to expand the liquid resin; a curing means for curing the expanded liquid resin; A protective member forming apparatus comprising: The liquid resin supply unit includes: a first supply unit that supplies a first liquid resin; a second supply unit that supplies a second liquid resin having a weaker adhesive strength than the first liquid resin; Equipped with A protective member forming device characterized by being configured with a control unit that supplies the first liquid resin by the first supply unit, then supplies the second liquid resin to the central portion of the first liquid resin by the second supply unit, spreads the first liquid resin and the second liquid resin over the entire surface of one side of the wafer by the lifting mechanism and hardens them by the hardening means, and adheres the second resin, which is the hardened second liquid resin, in a circular shape to the central portion of one side of the wafer, while adhering the first resin, which is the hardened first liquid resin, to the outside of the second resin.

2. 2. A method for forming a protective member by spreading and curing a liquid resin over the entire surface of one side of a wafer using the protective member forming apparatus according to claim 1, comprising: a first liquid resin supplying step of supplying the first liquid resin to the extension table side; a second liquid resin supplying step of supplying the second liquid resin to a central portion of the first liquid resin; an expanding step of moving the expansion table and the holding table relatively closer to each other in a vertical direction to spread the first liquid resin and the second liquid resin over the entire surface of one side of the wafer; a curing step of curing the first liquid resin and the second liquid resin; 1. A method for forming a protective member, comprising the steps of: forming a protective member on the entire surface of one side of a wafer through the steps of:

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