Protective member formation method and protective member formation device

Abstract

To prevent deformation of an outer peripheral part in a liquid resin, when anoxia gas such as nitrogen is supplied.SOLUTION: A protective member formation method cures an ultraviolet curable type liquid resin (M) expanded to the whole surface of a lower surface (W2) of a wafer (W), and forms a protective member (H). The liquid resin is supplied to a glass table (16), then the glass table is made to approach a holding table (201) holding the wafer, and the glass table and the holding table are connected to each other with an outer periphery connection part (22) in the outside of the wafer, and the liquid resin is expanded while a resin expansion chamber (23) is formed. The liquid resin is irradiated with ultraviolet light for a predetermined time, the liquid resin is semi-cured, then the air inside of the resin expansion chamber is replaced with anoxia gas such as nitrogen, then the liquid resin is irradiated with ultraviolet light and the liquid resin is completely cured.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a method for forming a protective member and an apparatus for forming a protective member.

Background Art

[0002] Patent Document 1 discloses a protective member forming apparatus that spreads and cures an ultraviolet curable liquid resin on one surface of a sliced wafer obtained by slicing an ingot to form a protective member composed of the resin and a sheet. In the formation of such a protective member, the liquid resin is spread over the entire surface of one side of the wafer and then irradiated with ultraviolet rays to cure the liquid resin.

[0003] Here, in Patent Document 2, in order to prevent the curing of the liquid resin from being inhibited by oxygen in the air when irradiating ultraviolet rays, nitrogen is injected from a plurality of injection ports so as to cover the atmosphere of the entire circumference of the outer periphery of the liquid resin, and the time until the liquid resin is cured is shortened.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when nitrogen is injected as in Patent Document 2, the outer peripheral portion of the liquid resin spread by the airflow due to such injection is pushed toward the center of the wafer. For this reason, there is a problem that the thickness of the outer peripheral portion of the liquid resin changes and the cured resin does not have a uniform thickness.

[0006] The present invention has been made in view of such a point, and an object thereof is to provide a method for forming a protective member and a protective member forming apparatus capable of preventing deformation of an outer peripheral portion of a liquid resin when supplying an oxygen-free gas such as nitrogen.

Means for Solving the Problems

[0007] A method for forming a protective member according to an aspect of the present invention is a method for forming a protective member by curing an ultraviolet curable liquid resin expanded over the entire surface of one side of a wafer, the method including: a liquid resin supply step of supplying the liquid resin to the wafer held by a glass table or a holding table; an expansion step of bringing the glass table and the holding table holding the wafer closer to each other, connecting the glass table and the holding table on the outside of the wafer by a ring-shaped outer peripheral connection portion to form a resin expansion chamber, and expanding the liquid resin; a separation step of separating the holding table from the wafer; a semi-curing step of irradiating the liquid resin with ultraviolet rays for a predetermined time to semi-cure the liquid resin; and a complete curing step of replacing the inside of the resin expansion chamber with an oxygen-free gas and then irradiating the liquid resin with ultraviolet rays to completely cure the liquid resin.

[0008] The protective member forming apparatus according to one aspect of the present invention includes a holding table that sucks and holds a wafer by a wafer holding surface, a glass table that holds the sheet by a sheet holding surface facing the wafer holding surface, a sheet conveying mechanism that conveys the sheet to the sheet holding surface, a resin supply nozzle that supplies a liquid resin to the sheet held on the sheet holding surface, a lifting mechanism that relatively approaches and separates the holding table and the glass table, and an outer peripheral connection portion that connects the wafer holding surface and the sheet holding surface outside the wafer held on the holding table to form a resin expansion chamber when the holding table and the glass table are relatively approached by the lifting mechanism, a light source that irradiates ultraviolet rays to cure the liquid resin, and a control unit. The control unit controls forming the resin expansion chamber to expand the liquid resin, separating the wafer from the wafer holding surface in a state where the resin expansion chamber is formed, irradiating the liquid resin with ultraviolet rays for a predetermined time to semi-cure the liquid resin, replacing the resin expansion chamber with an oxygen-free gas, and irradiating the liquid resin with ultraviolet rays to completely cure the liquid resin.

Advantages of the Invention

[0009] According to the present invention, after irradiating the liquid resin with ultraviolet rays for a predetermined time to semi-cure it, the resin expansion chamber is replaced with an oxygen-free gas, so that the liquid resin can be prevented from being deformed by the airflow caused by the replacement, and the thickness uniformity of the outer peripheral portion of the liquid resin can be achieved. Further, during the period from semi-curing to complete curing, the resin expansion chamber can be filled with an oxygen-free gas, and it is possible to avoid an increase in the time required for curing the liquid resin.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0011] Hereinafter, with reference to the accompanying drawings, a protective member forming apparatus according to an embodiment will be described. FIG. 1 is a schematic perspective view of the protective member forming apparatus according to the embodiment.

[0012] The X-axis direction, Y-axis direction, and Z-axis direction shown in each figure are perpendicular to each other. The X-axis direction and Y-axis direction are substantially horizontal directions, and the Z-axis direction is the vertical direction (up and down direction). In each figure, among the double-headed arrows indicating the X-axis direction, the side with the letter X attached is the left side (rear side of the paper) of the apparatus, and the side without the letter X attached is the right side (front side of the paper) of the apparatus. Among the double-headed arrows indicating the Y-axis direction, the side with the letter Y attached is the front side (left side of the paper) of the apparatus, and the side without the letter Y attached is the rear side (right side of the paper) of the apparatus. Among the double-headed arrows indicating the Z-axis direction, the side with the letter Z attached is the upper side, and the side without the letter Z attached is the lower side.

[0013] The protective member forming apparatus 1 shown in FIG. 1 is an example of an apparatus that forms a protective member H (see FIG. 8) by irradiating ultraviolet rays onto a liquid resin M (see FIG. 5) expanded over the entire one surface of a wafer W to cure it. In FIG. 1, the outer casing 10 of the protective member forming apparatus 1 is shown by a dashed line, and the components inside the outer casing 10 are shown in a perspective view. Among the wafer W, the surface facing upward during the processing in the protective member forming apparatus 1 is the upper surface W1, and the surface facing downward is the lower surface W2, and such lower surface W2 is the one surface.

[0014] The wafer W is, for example, a disk-shaped as-cut wafer cut out from an ingot such as a cylindrical silicon. Note that the wafer W is not limited to the as-cut wafer before device formation, and may be a device wafer after device formation or the like.

[0015] The protective member forming apparatus 1 includes a cassette accommodating portion 11 at one end side (front end side) in the Y-axis direction of the outer casing 10. Inside the cassette accommodating portion 11, a cassette C capable of accommodating a plurality of wafers W is placed.

[0016] A sheet cutting table 14 is provided at a position on the rear side in the Y-axis direction of the cassette accommodating portion 11. The sheet cutting table 14 is provided with a sheet cutter 141 that cuts a sheet S, which will be described later, adhered to the wafer W along the outer shape of the wafer W.

[0017] A first transfer mechanism 12 for loading and unloading the wafer W with respect to the cassette C is provided on the left side in the X-axis direction with respect to the sheet cutting table 14. The first transfer mechanism 12 includes a robot hand 122 supported on a pedestal 121, and transfers the wafer W between the cassette accommodating portion 11 and the temporary placement table 13, and between the cassette accommodating portion 11 and the sheet cutting table 14 by moving the pedestal 121 in the X-axis direction and operating the robot hand 122.

[0018] The protective member forming apparatus 1 includes a base 15 on the rear side in the Y-axis direction with respect to the sheet cutting table 14. A glass table (protective member forming table) 16 is provided on the base 15. The glass table 16 is made of a light-transmitting material such as quartz glass and is formed in a disk shape. The upper surface of the glass table 16 is a flat sheet holding surface 161 for placing and holding the sheet S.

[0019] The protective member forming apparatus 1 includes a sheet conveying mechanism 17 that conveys and places a sheet S on the sheet holding surface 161 of a glass table 16. The sheet conveying mechanism 17 includes a sheet supply unit 171 that supports the sheet S wound in a roll shape, an arm 172 that is movable in the Y-axis direction, and a clamp unit 173 attached to the side surface of the arm 172. In the sheet conveying mechanism 17, the roll-shaped sheet S supported by the sheet supply unit 171 is held by the clamp unit 173, and the arm 172 is moved in the Y-axis direction to pull the sheet S, thereby placing the sheet S on the sheet holding surface 161 of the glass table 16.

[0020] The sheet S is made of a light-transmissive material. As the sheet S, for example, a film formed of polyethylene terephthalate or the like can be used. In addition, a sheet S made of other materials may be used.

[0021] A plurality of suction holes (all not shown) connected to a suction source are formed in the sheet holding surface 161 of the glass table 16. By applying a suction force to the suction holes by the operation of the suction source, the sheet S placed on the sheet holding surface 161 is suction-held on the sheet holding surface 161.

[0022] Near the glass table 16, a resin supply mechanism 18 for supplying a predetermined amount of liquid resin M (see FIG. 2) to the upper surface of the sheet S held on the sheet holding surface 161 is provided. The resin supply mechanism 18 includes a dispenser 181 connected to a tank 184 provided in a base 15, and a resin supply nozzle 183 to which a connecting pipe 182 extending from the dispenser 181 is connected.

[0023] The resin supply nozzle 183 is provided below the arm 172 and is movable in accordance with the movement of the arm 172 in the Y-axis direction by the sheet conveying mechanism 17. By such movement, it is possible to set the state where the resin supply nozzle 183 is positioned between the glass table 16 and a holding table 201 described later, and the state where the resin supply nozzle 183 is retracted from between them.

[0024] The liquid resin M stored in the tank 184 is sent by the dispenser 181 via the connecting pipe 182, and the liquid resin M is supplied (dropped) downward from the resin supply nozzle 183. The supply amount of the liquid resin M from the resin supply nozzle 183 can be adjusted by the dispenser 181.

[0025] The liquid resin M has the property of curing by external stimuli. In the present embodiment, an ultraviolet-curable liquid resin M that cures by irradiation with ultraviolet rays is used. The liquid resin M may be a thermosetting type.

[0026] The protective member forming apparatus 1 includes a wafer holding portion 20 disposed above the glass table 16. The wafer holding portion 20 is supported by a column 19, and the column 19 projects upward from the base 15 at a position on the front side in the Y-axis direction with respect to the glass table 16. The column 19 is provided with a lifting mechanism 21 that moves the wafer holding portion 20 in the Z-axis direction to approach and separate from the glass table 16.

[0027] The lifting mechanism 21 includes a pair of guide rails 211 and a ball screw 212 extending in the Z-axis direction, and a lifting table 213 movably supported in the Z-axis direction with respect to the pair of guide rails 211. When the ball screw 212 is rotated by the driving force of the motor 214 in the lifting mechanism 21, the lifting table 213 moves in the Z-axis direction along the pair of guide rails 211.

[0028] The wafer holding part 20 is supported by the elevating table 213, and the wafer holding part 20 is moved in the Z-axis direction along with the elevating table 213. The wafer holding part 20 includes a disk-shaped holding table 201. On the lower surface side of the holding table 201, a disk-shaped porous member 202 (see FIG. 3) is provided. The lower surface of the porous member 202 is a wafer holding surface 203 located above the glass table 16. The wafer holding surface 203 is a surface substantially parallel to the sheet holding surface 161 of the glass table 16, and the sheet holding surface 161 faces the wafer holding surface 203. By the elevating mechanism 21, the holding table 201 and the glass table 16 are relatively approached and separated in the Z-axis direction.

[0029] In the wafer holding part 20 shown in FIG. 3, the porous member 202 communicates with a suction source 205 via a suction path 204. By the operation of the suction source 205, a suction force is applied to the porous member 202, and the upper surface W1 of the wafer W is suction-held by the wafer holding surface 203 of the holding table 201. A first valve 206 is disposed in the suction path 204. When the first valve 206 opens, the wafer W is suctioned by the porous member 202 and the wafer W is held by the wafer holding surface 203.

[0030] In the wafer holding part 20 shown in FIG. 3, a ring-shaped outer peripheral connection part 22 is disposed on an outer peripheral part 207 formed by the lower surface of the holding table 201 outside the wafer holding surface 203. The outer peripheral connection part 22 forms a resin expansion chamber 23 shown in FIG. 4. To form the resin expansion chamber 23 at the outer peripheral connection part 22, the elevating mechanism 21 lowers the holding table 201 and relatively approaches the holding table 201 and the glass table 16. At this time, as shown in FIG. 4, outside the wafer W held by the holding table 201, the wafer holding surface 203 and the sheet holding surface 161 of the glass table 16 are connected. By this connection, a resin expansion chamber 23 is formed, which is a closed space surrounded by the wafer holding surface 203, the sheet holding surface 161, and the outer peripheral connection part 22.

[0031] The outer peripheral connection part 22 is configured to be stretchable and can correspond to changes in the separation distance in the Z-axis direction between the holding table 201 and the glass table 16. In the present embodiment, the outer peripheral connection part 22 is formed in a bellows shape, but it is not limited to this configuration.

[0032] A negative pressure forming part 24 is provided in the wafer holding part 20 shown in FIG. 3. The negative pressure forming part 24 includes a suction port 241 formed in the outer peripheral part 207 of the holding table 201, a flow path 242 that communicates the suction port 241 and the suction source 205, and a second valve 243 disposed in the flow path 242 to open and close the flow path 242. After the resin expansion chamber 23 shown in FIG. 4 is formed, when the second valve 243 opens along with the operation of the suction source 205, suction from the suction port 241 into the resin expansion chamber 23 is performed and it is made into a negative pressure.

[0033] A nitrogen supply part (an oxygen-free gas supply part) 25 that supplies nitrogen as an oxygen-free gas is provided in the wafer holding part 20 shown in FIG. 3. The nitrogen supply part 25 includes a nitrogen supply source 251, a supply path 252 that connects the nitrogen supply source 251 and the flow path 242 on the downstream side of the second valve 243, and an opening and closing valve 253 disposed in the supply path 252 to open and close the supply path 252. The nitrogen supply part 25 controls the supply of nitrogen to the resin expansion chamber 23 by switching the opening and closing valve 253 with the second valve 243 closed (see FIG. 8). When nitrogen is supplied from the nitrogen supply source 251 to the resin expansion chamber 23 through the supply path 252 and the flow path 242, the resin expansion chamber 23 is filled with nitrogen.

[0034] The wafer holding part 20 shown in FIG. 3 includes a load detection part 26. The load detection part 26 can detect the vertical direction (Z-axis direction) load applied to the lower surface W2 of the wafer W.

[0035] Below the glass table 16 shown in Fig. 2, a curing mechanism 27 is provided for applying an external stimulus to the liquid resin M dropped onto the sheet S on the sheet holding surface 161 to cure it. The curing mechanism 27 includes a plurality of ultraviolet irradiation units 271 that serve as light sources capable of emitting ultraviolet rays UV (see Figs. 7 and 8), and irradiates the liquid resin M with ultraviolet rays UV through the translucent glass table 16 and sheet S to cure it. The light source used for the ultraviolet irradiation unit 271 may be an LED.

[0036] Returning to Fig. 1, a second transfer mechanism 28 is provided on the left side of the base 15 in the X-axis direction. The second transfer mechanism 28 includes a robot hand 282 supported on a pedestal 281, and transfers the wafer W between the glass table 16 and the sheet cutting table 14, and between the temporary placement table 13 and the glass table 16 by moving the pedestal 281 in the Y-axis direction and operating the robot hand 282.

[0037] The protective member forming apparatus 1 is comprehensively controlled by a control unit 40. The control unit 40 is composed of a processor that executes various processes and a storage unit (memory) that stores various parameters, programs, etc. In the storage unit of the control unit 40, as part of the control program, for example, a program for controlling the operations of the lifting mechanism 21 and each valve 206, 243, 253, etc. based on various conditions is stored.

[0038] The control unit 40 includes, as functional blocks, an extended control unit 41, a holding control unit 42, a semi-curing control unit 43, a full-curing control unit 44, and a replacement control unit 45. These functional blocks are realized by executing the program stored in the storage unit in the control unit 40. Note that the functional blocks of the control unit 40 shown in Fig. 1 show only the configurations related to the present invention, and other configurations are omitted.

[0039] The expansion control unit 41 controls the driving amount of the dispenser 181 in the resin supply mechanism 18, and causes a predetermined amount of the liquid resin M to be supplied to the upper surface of the glass table 16 or the sheet S by the resin supply nozzle 183. Further, the expansion control unit 41 controls the operation amount, operation direction, etc. of the wafer holding unit 20 by the lifting mechanism 21. Thereby, the glass table 16 and the holding table 201 can be connected by the outer peripheral connection portion 22 outside the wafer W, and the resin expansion chamber 23 can be formed. Further, as will be described later, the liquid resin M can be expanded by lowering the wafer holding unit 20 (see FIGS. 4 and 5).

[0040] The holding control unit 42 controls the opening and closing of the first valve 206, adsorbs and holds the wafer W on the wafer holding surface 203 of the holding table 201, or releases the adsorption and holding of the wafer W on the wafer holding surface 203 to separate the wafer W from the wafer holding surface 203.

[0041] The semi-curing control unit 43 controls the irradiation of the ultraviolet ray UV by the ultraviolet irradiation unit 271 (for example, irradiation time, intensity), and semi-cures the liquid resin M irradiated with the ultraviolet ray UV.

[0042] The complete curing control unit 44 controls the irradiation of the ultraviolet ray UV by the ultraviolet irradiation unit 271 (for example, irradiation time, intensity), and completely cures the liquid resin M irradiated with the ultraviolet ray UV.

[0043] The replacement control unit 45 controls the opening and closing of the second valve 243, communicates the suction source 205 with the resin expansion chamber 23, and sucks the air inside the resin expansion chamber 23. Further, the replacement control unit 45 controls the opening and closing of the on-off valve 253, communicates the nitrogen supply source 251 with the resin expansion chamber 23, and supplies nitrogen into the resin expansion chamber 23. Thereby, the air inside the resin expansion chamber 23 can be replaced with nitrogen.

[0044] Note that the functions of the control units 41 to 45 described above are realized by the operations of a processor, a memory, etc. that constitute the control unit 40, and do not mean that the control units 41 to 45 are composed of independent electronic components. Further, in FIG. 1, only the connection relationship between the control unit 40 and the wafer holding unit 20 is schematically shown, but the control unit 40 is also connected so as to be able to transmit and receive signals to each part of the protection member forming apparatus 1 other than the wafer holding unit 20.

[0045] Subsequently, with reference to FIGS. 2 to 8, a method for forming the protection member H (see FIG. 9) by the protection member forming apparatus 1 of the present embodiment will be described. The method for forming the protection member in the present embodiment is carried out in the order of a liquid resin supply step, an expansion step, a separation step, a semi-curing step, and a complete curing step.

[0046] FIGS. 2A and 2B show the liquid resin supply step in the formation of the protection member. Here, it is assumed that before the implementation of the liquid resin supply step, a sheet S of a predetermined size is placed and held on the sheet holding surface 161 of the glass table 16 as shown in FIG. 2A by the sheet transport mechanism 17 (see FIG. 1). In the liquid resin supply step, the resin supply nozzle 183 of the resin supply mechanism 18 is positioned above the sheet S placed on the sheet holding surface 161. Such positioning is carried out by the sheet transport mechanism 17 that moves the arm 172 in the Y-axis direction.

[0047] After the positioning of the resin supply nozzle 183, the dispenser 181 (see FIG. 1) is controlled via the expansion control unit 41, and as shown in FIG. 2B, the liquid resin M is sent to the resin supply nozzle 183 and the liquid resin M is supplied (dropped) from the resin supply nozzle 183 toward the sheet S on the upper surface side of the glass table 16. The liquid resin M supplied from the resin supply nozzle 183 accumulates near the center of the upper surface of the sheet S in a range narrower than the area of the wafer W.

[0048] Figures 3 to 5 show the expansion process in the formation of the protective member. In the expansion process, during or before the implementation of the liquid resin supply process, as shown in Figure 3, the upper surface W1 of the wafer W is sucked and held on the wafer holding surface 203 of the holding table 201. In this state, in the expansion process, the wafer W held on the holding table 201 is positioned opposite to the upper side of the liquid resin M on the sheet S. Then, the motor 214 of the lifting mechanism 21 is controlled via the expansion control unit 41, and the holding table 201 holding the wafer W is lowered at a predetermined feed rate to approach the glass table 16.

[0049] Due to the lowering of the holding table 201, as shown in Figure 4, the lower surface W2 of the wafer W approaches the glass table 16 and contacts the liquid resin M. Then, the liquid resin M is pressed by the lower surface W2 of the wafer W, and the liquid resin M is expanded in the radial direction of the wafer W. As shown in Figure 3, the liquid resin M before the lower surface W2 of the wafer W contacts is gathered near the center of the sheet S, and by being pressed by the wafer W as shown in Figure 4, the liquid resin M is expanded toward the outer edge side of the wafer W.

[0050] During the expansion of the liquid resin M, the outer peripheral connection portion 22 disposed on the outer peripheral portion 207 of the holding table 201 abuts on the upper surface of the sheet S placed on the glass table 16. Outside the wafer W held on the holding table 201, the holding table 201 and the glass table 16 are connected (coupled), and by this connection, a resin expansion chamber 23 is formed, which is a closed space surrounded by the wafer holding surface 203, the sheet holding surface 161, and the ring-shaped outer peripheral connection portion 22.

[0051] After the formation of the resin expansion chamber 23, as shown in Figure 5, the second valve 243 is opened under the control of the replacement control unit 45, and the air in the resin expansion chamber 23 is sucked from the suction port 241. While reducing the pressure in the resin expansion chamber 23, the holding table 201 is further lowered to approach the glass table 16. The resin expansion chamber 23 is depressurized to a negative pressure state, and by the suction from the suction port 241, the liquid resin M is further expanded toward the outer peripheral side in the radial direction, and the liquid resin M is expanded so as to cover the entire lower surface W2 of the wafer W.

[0052] In addition, when adjusting the descending amount of the holding table 201 according to the expansion state of the liquid resin M, the motor 214 may be controlled by the expansion control unit 41 based on the detection result of the load detection unit 26.

[0053] When the expansion process is completed and the entire lower surface W2 of the wafer W is covered with the liquid resin M, the separation process is performed. FIG. 6 shows the separation process in the formation of the protective member. In the separation process, the first valve 206 is controlled via the holding control unit 42, and the adsorption holding of the wafer W on the wafer holding surface 203 is released. Further, control is performed to close the second valve 243, and the suction of the air in the resin expansion chamber 23 is stopped. Furthermore, the motor 214 of the lifting mechanism 21 is controlled to raise the holding table 201 holding the wafer W by a predetermined amount. At this time, although the outer peripheral connection portion 22 extends in the vertical direction, the contact between the outer peripheral connection portion 22 and the upper surface of the sheet S placed on the glass table 16 is maintained, and the state where the resin expansion chamber 23 is formed and closed is also maintained.

[0054] In the separation process, with the resin expansion chamber 23 formed, the adsorption holding of the wafer W on the wafer holding surface 203 is released and the holding table 201 is raised, and the wafer holding surface 203 is separated from the wafer W. Note that, before the semi-curing process and the complete curing process, by performing the separation process, the force that smoothed the wafer W following the wafer holding surface 203 by the adsorption holding of the holding table 201 is released, and the undulation and warpage of the wafer W are restored.

[0055] When the separation process is completed and the wafer holding surface 203 is separated from the wafer W, the semi-curing process is performed. FIG. 7 shows the semi-curing process in the formation of the protective member.

[0056] In the semi-curing process, the irradiation of ultraviolet light UV by the ultraviolet irradiation unit 271 is controlled via the semi-curing control unit 43, and ultraviolet light UV with an intensity (wavelength) for curing the liquid resin M is irradiated from the ultraviolet irradiation unit 271 toward the sheet holding surface 161. The ultraviolet light UV emitted from the ultraviolet irradiation unit 271 passes through the glass table 16 and the sheet S and reaches the liquid resin M, and the liquid resin M, which is an ultraviolet curable resin, is semi-cured. Here, the irradiation time of the ultraviolet light UV in the semi-curing process is only a predetermined time, in other words, it is controlled via the semi-curing control unit 43 so that the irradiation time is shorter than the irradiation time of the ultraviolet light UV required for complete curing of the liquid resin M. Here, the semi-cured state of the liquid resin M is a state in which the curing of the liquid resin M is starting and fluidity remains, which is a state called the so-called B-stage.

[0057] When the semi-curing process is completed and the liquid resin M is semi-cured, the complete curing process is carried out. FIG. 8 shows the complete curing process in the formation of the protective member.

[0058] In the complete curing process, the on-off valve 253 is opened under the control of the substitution control unit 45, and the nitrogen supply source 251 and the resin expansion chamber 23 are communicated through the supply path 252 and the flow path 242, and nitrogen is supplied into the resin expansion chamber 23. Since nitrogen is supplied to the resin expansion chamber 23, which is depressurized to a negative pressure state in the above-described expansion process, the air inside the resin expansion chamber 23 is replaced with nitrogen.

[0059] Also, in the complete curing process, after or simultaneously with the replacement of the inside of the resin expansion chamber 23 with nitrogen, the irradiation of ultraviolet light UV by the ultraviolet irradiation unit 271 is controlled via the complete curing control unit 44. As a result, similar to the semi-curing process, the liquid resin M is irradiated with ultraviolet light UV by the ultraviolet irradiation unit 271, and the liquid resin M, which is an ultraviolet curable resin, is completely cured. In other words, under the control of the complete curing control unit 44, the irradiation time of the ultraviolet light UV required for complete curing of the liquid resin M after completion of the semi-curing process is set. By the complete curing of the liquid resin M, a protective member H covering the entire lower surface W2 of the wafer W is formed, and the lower surface W2 of the wafer W is protected by the protective member H.

[0060] According to the above embodiment, when nitrogen is supplied to the resin expansion chamber 23 through the flow path 242 and the suction port 241, the liquid resin M can be brought into a semi-cured state. Thereby, even when a force is applied to press the outer periphery of the liquid resin M by the airflow of nitrogen jetted from the suction port 241, deformation of the liquid resin M can be prevented. Thereby, the thickness of the liquid resin M completely cured by the protective member H can be made uniform, and the processing accuracy of the wafer W after the formation of the protective member H can be maintained favorably.

[0061] Also, while the liquid resin M is semi-cured and then completely cured, the resin expansion chamber 23 can be filled with nitrogen. Thereby, the outer periphery of the liquid resin M is blocked from oxygen in the air by nitrogen, and the photopolymerization reaction of ultraviolet curing is not inhibited by oxygen. Therefore, the liquid resin M can be cured in a short time by irradiation with ultraviolet rays UV, and the time of the complete curing process can be shortened.

[0062] Note that the present invention is not limited to the above embodiment, and various modifications can be made and implemented. In each of the above embodiments, the sizes, shapes, etc. illustrated in the attached drawings are not limited thereto, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, it can be appropriately changed and implemented as long as it does not deviate from the scope of the object of the present invention.

[0063] In the above embodiment, nitrogen (oxygen-free gas) supplied to the resin expansion chamber 23 is jetted through the flow path 242 and the suction port 241, but it is not limited thereto, and various modifications are possible. For example, an injection port used only for jetting nitrogen may be formed in the holding table 201, a supply path 252 may be connected to the injection port, and nitrogen may be jetted from the injection port, or the supply path 252 may be connected to a porous member 202 to jet nitrogen from the wafer holding surface 203. Further, an injection port for jetting nitrogen may be provided in the outer peripheral connection portion 22. After the liquid resin M is semi-cured, by jetting nitrogen, the nitrogen supply time can be shortened.

[0064] Also, from the semi-curing process to the full-curing process, the ultraviolet ray UV may be continuously irradiated by the ultraviolet irradiation unit 271, or during the supply of nitrogen to the resin expansion chamber 23, the irradiation of the ultraviolet ray UV may be stopped, and after the supply of nitrogen is completed, the irradiation of the ultraviolet ray UV in the full-curing process may be started.

[0065] Also, the supply of the liquid resin M in the liquid resin supply process may be performed on the lower surface W2 of the wafer W held by the holding table 201.

Industrial Applicability

[0066] As described above, the present invention can prevent the deformation of the liquid resin M by supplying an oxygen-free gas such as nitrogen, and has an effect of improving the processing accuracy of the wafer W by equalizing the thickness of the liquid resin M while curing the liquid resin M in a short time.

Explanation of Signs

[0067] 1: Protection member forming device 16: Glass table 161: Sheet holding surface 17: Sheet conveying mechanism 183: Resin supply nozzle 201: Holding table 203: Wafer holding surface 21: Lifting mechanism 22: Outer peripheral connection part 23: Resin expansion chamber 271: Ultraviolet irradiation unit (light source) 40: Control unit H: Protection member M: Liquid resin S: Sheet UV: Ultraviolet ray W: Wafer W2: Lower surface (one surface)

Claims

1. A method for forming a protective member by curing a liquid ultraviolet-curable resin that has been expanded over the entire surface of one side of a wafer, comprising: a liquid resin supply step of supplying the liquid resin to a wafer held by a glass table or a holding table; an expansion step of bringing the glass table and the holding table holding the wafer closer together, connecting the glass table and the holding table at an outer periphery of the wafer with a ring-shaped outer peripheral connection portion to form a resin expansion chamber, and expanding the liquid resin while forming the resin expansion chamber; a separation step of separating the holding table from the wafer; a semi-curing step of irradiating the liquid resin with ultraviolet light for a predetermined time to semi-cure the liquid resin; a complete curing step of replacing the inside of the resin expansion chamber with an oxygen-free gas and then irradiating the liquid resin with ultraviolet light to completely cure the liquid resin; The method for forming a protective member comprises the above steps.

2. A protective member forming apparatus comprising: a holding table that sucks and holds a wafer by a wafer holding surface; a glass table that holds a sheet by a sheet holding surface facing the wafer holding surface; a sheet transfer mechanism that transfers the sheet to the sheet holding surface; a resin supply nozzle that supplies a liquid resin to the sheet held on the sheet holding surface; a lifting mechanism that relatively approaches and separates the holding table and the glass table; an outer peripheral connection portion that connects the wafer holding surface and the sheet holding surface outside the wafer held by the holding table to form a resin expansion chamber when the holding table and the glass table are relatively approached by the lifting mechanism; a light source that irradiates ultraviolet light to cure the liquid resin; and a control unit, wherein the control unit forms the resin expansion chamber and expands the liquid resin; separates the wafer from the wafer holding surface while the resin expansion chamber is formed; irradiates the liquid resin with ultraviolet light for a predetermined time to semi-cure the liquid resin; replaces the resin expansion chamber with an oxygen-free gas; irradiates the liquid resin with ultraviolet light to completely cure the liquid resin; and controls the above operations. The protective member forming apparatus is as described above.

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