Method for determining the curing of liquid resin, apparatus for forming protective member, and method for forming protective member

Abstract

To provide a liquid resin curing determination method capable of surely determining that a liquid resin has been cured.SOLUTION: When determining whether a liquid resin has been cured by applying an external stimulus to the liquid resin (31, 33) spread over the entire surface of one side (Wb) of a wafer (W), a vertical load (Q) on one side of the wafer is detected so as to be capable of detecting shrinkage of the liquid resin when the liquid resin is cured, and when the load becomes smaller than a preset threshold value (Qe), it is determined that the liquid resin has been cured.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a method for determining the curing of a liquid resin 、 A protective member forming apparatus , and method for forming protective members and relates thereto.

Background Art

[0002] When performing grinding or the like on a wafer, a protective member is formed to protect the entire one surface of the wafer. A protective member forming apparatus for forming a protective member supplies a liquid resin onto a sheet placed on a table, lowers a holding unit that holds the wafer above the table, spreads the liquid resin with the wafer held by the holding unit, and then cures the liquid resin to form a protective member composed of a resin and a sheet on the entire one surface of the wafer.

[0003] The liquid resin for forming the protective member is one that cures by applying a specific external stimulus, such as an ultraviolet-curable resin or a heat-curable resin. For example, in the case of an ultraviolet-curable liquid resin, it is cured by irradiating ultraviolet rays for a preset time.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When forming a protective member on one surface of a wafer using an ultraviolet-curable liquid resin, based on the amount of the liquid resin supplied onto the sheet or the like, the irradiation time of ultraviolet rays required for curing the liquid resin is preset and managed so that ultraviolet rays are irradiated for the set predetermined irradiation time. However, there is a problem that due to deterioration of the ultraviolet irradiation unit that irradiates ultraviolet rays or differences in lots of the liquid resin, variations occur in the degree of progress of curing, and there are portions where the liquid resin is not sufficiently cured even after irradiating ultraviolet rays for a predetermined time.

[0006] Similar problems exist when using thermosetting liquid resins. Due to deterioration of heaters or other equipment used to heat the liquid resin, or differences in the batch of liquid resin used, there was a risk that some parts of the liquid resin would not be sufficiently cured even after heating for a predetermined time.

[0007] The present invention has been made in view of the above, and provides a method for determining the curing of a liquid resin that can reliably determine when a liquid resin has hardened. 、 Protective member forming apparatus , and method for forming protective members The purpose is to provide. [Means for solving the problem]

[0008] One aspect of the present invention is a method for determining the curing of a liquid resin by applying an external stimulus to a liquid resin spread over the entire surface of one side of a wafer, wherein it is determined that the liquid resin has hardened. After spreading the liquid resin over the entire surface of one side of the wafer, move the wafer away from the liquid resin, reducing the load on the underside of the wafer and the liquid resin to near zero, and then apply an external stimulus to the liquid resin. To detect shrinkage during the curing of the liquid resin, a load perpendicular to one side of the wafer is detected, and the load is set to a preset value. negative values When it becomes smaller than the threshold The bottom surface of the wafer is pulled downwards. It is determined that the liquid resin has hardened.

[0009] One aspect of the present invention is a sheet having an area larger than one side of a wafer. Applicable A liquid resin that hardens due to external stimuli is used between the wafer and the substrate. Applicable A protective member forming apparatus comprising a sheet and a resin that has been spread over the entire surface of one side of a wafer and then cured by applying an external stimulus, the apparatus comprising a curing mechanism for applying an external stimulus to the liquid resin, Applicable A load detection unit detects a load perpendicular to one side of the wafer, and the load detected by the load detection unit is set to a preset value. negative values When it becomes smaller than the threshold The bottom surface of the wafer is pulled downwards. A determination unit that determines that the liquid resin has hardened, A control unit stops moving the wafer towards the liquid resin, and when the liquid resin is spread over the entire surface of one side of the wafer, and the load detected by the load detection unit begins to decrease as the load rises between the bottom surface of the wafer and the liquid resin and reaches a predetermined value, moves the wafer away from the liquid resin, thereby bringing the load detected by the load detection unit closer to zero. It is equipped with. One aspect of the present invention is a method for forming a protective member that protects the entire surface of one side of a wafer, comprising: a liquid resin supply step of supplying a liquid resin that hardens upon external stimuli to a sheet; a spreading step of pressing the liquid resin with the wafer held by a holding part to spread the liquid resin over the entire surface of one side of the wafer; and a curing step of stopping the movement of the holding part once the liquid resin has been spread over the entire surface of one side of the wafer in the spreading step, and when the load on the lower surface of the wafer and the liquid resin begins to rise and falls to a predetermined value, moving the wafer in a direction away from the liquid resin to bring the load on the lower surface of the wafer and the liquid resin closer to zero, and then curing the liquid resin, wherein the curing step includes a determination step of determining that the liquid resin has hardened when the load detected by a load detection part becomes smaller than a predetermined negative threshold value, causing the lower surface of the wafer to be pulled downward. [Effects of the Invention]

[0010] Method for Judging Curing of Liquid Resin of Present Invention 、 Protective Member Forming Apparatus , and method for forming protective members According to this, since a vertical load acting on one surface of the wafer is detected and curing is judged based on the load, it is possible to surely judge that the liquid resin has cured.

Brief Description of Drawings

[0011] [Figure 1] It is a perspective view showing the protective member forming apparatus of this embodiment. [Figure 2] It is a partial cross-sectional view of the protective member forming apparatus. [Figure 3] It is an explanatory view showing the sheet carrying-in process in the protective member forming apparatus. [Figure 4] It is an explanatory view showing the liquid resin supply process in the protective member forming apparatus. [Figure 5] It is an explanatory view showing the wafer holding process in the protective member forming apparatus. [Figure 6] It is an explanatory view showing the spreading process in the protective member forming apparatus. [Figure 7] It is an explanatory view showing the curing process in the protective member forming apparatus. [Figure 8] It is an explanatory view showing a modification example of the curing process in the protective member forming apparatus. [Figure 9] It is a graph for explaining the method for judging curing of the liquid resin of this embodiment.

Modes for Carrying Out the Invention

[0012] Hereinafter, referring to the attached drawings, the method for judging curing of the liquid resin and the protective member forming apparatus according to this embodiment will be described. FIGS. 1 and 2 show the whole and a part of the protective member forming apparatus according to this embodiment. FIGS. 3 to 7 are diagrams for explaining each process performed by the protective member forming apparatus. FIG. 8 is a diagram showing a modification example of the curing process (curing mechanism) in the protective member forming apparatus. FIG. 9 is a graph for explaining the method for judging curing of the liquid resin according to this embodiment.

[0013] 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 (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 taken as the left side, and the side without the letter X attached is taken as the right side. Among the double-headed arrows indicating the Y-axis direction, the side with the letter Y attached is taken as the front side, and the side without the letter Y attached is taken as the rear side. Among the double-headed arrows indicating the Z-axis direction, the side with the letter Z attached is taken as the upper side, and the side without the letter Z attached is taken as the lower side.

[0014] The protective member forming apparatus 1 shown in FIG. 1 is an example of an apparatus that forms a protective member by applying an external stimulus to a liquid resin spread over the entire surface of one side of a wafer W and curing it. In FIG. 1, the outer housing 10 of the protective member forming apparatus 1 is shown by a dashed line, and the components inside the outer housing 10 are shown in a perspective view state. Among the wafers W, the surface facing upward during the processing in the protective member forming apparatus 1 is defined as the upper surface Wa, and the surface facing downward is defined as the lower surface Wb.

[0015] Although details will be described later, in the protective member forming apparatus 1, a liquid resin 31 (see FIGS. 2, 4, and 5) is supplied onto a sheet 30 placed on a protective member forming stage 16, and the wafer W held by the wafer holding portion 20 is operated to be pressed against the liquid resin 31 from above the protective member forming stage 16. By pressing the lower surface Wb of the wafer W toward the sheet 30, the liquid resin 31 is spread between the wafer W and the sheet 30 (see FIG. 6). In this state, an external stimulus is applied to the liquid resin 31 to cure it, and a protective member 32 is formed by the cured resin and the sheet 30 (see FIG. 7).

[0016] Such a series of operations is performed under the control of a control unit 40 (FIG. 1) that overall controls the protective member forming apparatus 1. Regarding the operations of each part described below, when the subject of control is not specified, it is assumed that the operation is controlled by a control signal sent from the control unit 40.

[0017] Wafer W is, for example, a disc-shaped azu slice wafer cut from a cylindrical silicon ingot. Note that wafer W is not limited to an azu slice wafer before device formation; it may also be a device wafer after device formation.

[0018] The protective member forming apparatus 1 is equipped with a cassette housing section 11 at one end (the left end) in the X-axis direction of the external housing 10. The cassette housing section 11 has two upper and lower storage spaces 111 and 112. The upper storage space 111 is where the input cassette C1, which houses multiple wafers W before the protective member 32 is formed, is placed. The lower storage space 112 is where the output cassette C2, which houses wafers W after the protective member 32 has been formed, is placed. Both cassette C1 and cassette C2 can accommodate multiple wafers W.

[0019] A temporary placement table 13 and a sheet cutting table 14 are provided on the right side of the cassette storage section 11 in the X-axis direction. The temporary placement table 13 is located on the upper side, and the sheet cutting table 14 is located on the lower side. The temporary placement table 13 is provided with a wafer detection unit 131 that detects the center position and orientation of the wafer W before the protective member 32 is formed. The sheet cutting table 14 is provided with a sheet cutter 141 that cuts the sheet 30 attached to the wafer W along the outer shape of the wafer W.

[0020] A first transport mechanism 12 is provided on the front side in the Y-axis direction relative to the temporary storage table 13 and the sheet cutting table 14, for loading and unloading wafers W to and from each cassette C1 and C2. The first transport mechanism 12 includes a robot hand 122 supported on a base 121, and the base 121 is supported so as to be movable along a pair of guide rails 123 extending in the Y-axis direction. The base 121 has a threaded portion (not shown) that screws into a ball screw 124 extending in the Y-axis direction. When the ball screw 124 is rotated by the driving force of the motor, the base 121 moves in the Y-axis direction.

[0021] The first transport mechanism 12 transports wafers W between the cassette storage section 11, the temporary storage table 13, and the sheet cutting table 14 by moving the base 121 in the Y-axis direction and operating the robot hand 122. More specifically, the first transport mechanism 12 can remove wafers W from cassette C1 in the storage space 111 and place them on the temporary storage table 13 before the protective member 32 is formed. The first transport mechanism 12 can also remove wafers W after the protective member 32 has been formed from the sheet cutting table 14 and place them in cassette C2 in the storage space 112.

[0022] The protective member forming apparatus 1 is equipped with a base 15 on the right side in the X-axis direction relative to the temporary placement table 13 and the sheet cutting table 14. A protective member forming stage 16 is provided on the base 15. The protective member forming stage 16 is made of a translucent material such as quartz glass and is formed in a disc shape. The upper surface of the protective member forming stage 16 is a flat sheet support surface 161 on which the sheet 30 is placed.

[0023] The protective member forming stage 16 is equipped with a sheet conveying mechanism 17 for conveying and placing the sheet 30 onto the sheet support surface 161. The sheet conveying mechanism 17 comprises a sheet supply section 171 that supports the rolled sheet 30, an arm 172 that is movable in the X-axis direction, and a clamp section 173 attached to the side of the arm 172. In the sheet conveying mechanism 17, the rolled sheet 30 supported by the sheet supply section 171 is held by the clamp section 173, and the sheet 30 is placed on the sheet support surface 161 of the protective member forming stage 16 by moving the arm 172 in the X-axis direction and pulling the sheet 30.

[0024] The sheet 30 is made of a light-transmitting material. For example, a film made of polyethylene terephthalate can be used as the sheet 30. However, a sheet 30 made of a material other than this may also be used.

[0025] Multiple suction holes (not shown) are formed in the sheet support surface 161 of the protective member forming stage 16. The suction holes are connected to a suction source 162 (see Figure 2). By operating the suction source 162 and applying suction force to the suction holes, the sheet 30 placed on the sheet support surface 161 is held in place by suction to the sheet support surface 161.

[0026] Near the protective member forming stage 16, a resin supply mechanism 18 is provided to supply a predetermined amount of liquid resin 31 to the upper surface of the sheet 30 on the sheet support surface 161. The resin supply mechanism 18 comprises a dispenser 181 connected to a tank 184 provided in the base 15, and a resin supply nozzle 183 to which a connecting pipe 182 extending from the dispenser 181 is connected. The resin supply nozzle 183 is rotatable about an axis oriented in the Z-axis direction, and can be positioned above the protective member forming stage 16 or retracted from above the protective member forming stage 16.

[0027] Liquid resin 31 stored in tank 184 is supplied by dispenser 181 via connecting pipe 182, and the liquid resin 31 is dripped downward from resin supply nozzle 183. The amount of liquid resin 31 supplied from resin supply nozzle 183 can be adjusted by dispenser 181.

[0028] The liquid resin 31 has the property of hardening in response to external stimuli. In this embodiment, an ultraviolet-curing resin that hardens upon irradiation with ultraviolet light is used.

[0029] A column 19 is provided on the left side of the protective member formation stage 16 in the X-axis direction, projecting upward from the base 15. The column 19 is provided with a lifting mechanism 21 that moves the wafer holding section 20 in the Z-axis direction to move it closer to and further away from the protective member formation stage 16. The lifting mechanism 21 includes a pair of guide rails 211 extending in the Z-axis direction, a lifting table 212 supported so as to be movable in the Z-axis direction relative to the pair of guide rails 211, and a ball screw 213 (see Figure 2) extending in the Z-axis direction and screwed into a threaded section 215 (see Figure 2) of the lifting table 212. When the ball screw 213 is rotated by the driving force of the motor 214, the lifting table 212 moves in the Z-axis direction along the pair of guide rails 211. When the ball screw 213 is rotated in a first direction, the lifting table 212 moves downward, and when the ball screw 213 is rotated in a second direction, the lifting table 212 moves upward.

[0030] The wafer holder 20 is supported by a lifting table 212, and the wafer holder 20 moves in the Z-axis direction in conjunction with the lifting table 212. The wafer holder 20 includes a disc-shaped holding table 201. As shown in Figures 2, 5 to 7, a disc-shaped porous member 202 is provided on the lower surface of the holding table 201. The lower surface of the porous member 202 is the wafer holding surface 203 located above the protective member forming stage 16. The wafer holding surface 203 is substantially parallel to the sheet support surface 161 of the protective member forming stage 16.

[0031] As shown in Figure 2, the porous member 202 is connected to the suction source 205 via the suction passage 204. By operating the suction source 205 and applying suction force to the porous member 202, the upper surface Wa of the wafer W can be held by the wafer holding surface 203 through suction.

[0032] With the upper surface Wa of the wafer W held by the wafer holding surface 203 of the wafer holding section 20 (Figure 2), when the wafer holding section 20 is lowered by the lifting mechanism 21, the lower surface Wb of the wafer W comes into contact with the liquid resin 31 supplied onto the sheet 30, and the liquid resin 31 is spread out by the force of lowering the wafer W.

[0033] As shown in Figures 5 to 7, the wafer holding unit 20 is equipped with a load detection unit 22. Multiple load sensors 221 are provided at different positions on the upper surface of the holding table 201, and these load sensors 221 constitute the load detection unit 22. The load detection unit 22 can detect the vertical load (in the Z-axis direction) applied to the lower surface Wb of the wafer W based on the outputs of the multiple load sensors 221.

[0034] Multiple load sensors 221 are positioned at arbitrary locations that can appropriately detect the load applied to the lower surface Wb of the wafer W. For example, three load sensors 221 are positioned to surround a virtual central axis that extends in the Z-axis direction through the center of the holding table 201.

[0035] A curing mechanism 23 is provided at the bottom of the protective member forming stage 16 to cure the liquid resin 31 that has been dropped onto the sheet 30 on the sheet support surface 161 by applying external stimuli. The curing mechanism 23 is equipped with a plurality of ultraviolet irradiation units 231 that are capable of emitting ultraviolet UV (Figure 7), and cures the liquid resin 31 by irradiating it with ultraviolet UV through the light-transmitting protective member forming stage 16 and the sheet 30.

[0036] Furthermore, an imaging unit 24 is provided at the lower part of the protective member forming stage 16 to image the direction of the sheet support surface 161. The imaging unit 24 is a camera having a lens and an image sensor, and has an imaging range that allows it to image the outer edge of the liquid resin 31 being spread out on the sheet 30 on the sheet support surface 161, and the entire lower surface Wb of the wafer W when the liquid resin 31 is being spread out, from below the sheet support surface 161.

[0037] As shown in Figure 1, a second transport mechanism 25 is provided on the front side of the base 15 in the Y-axis direction. The second transport mechanism 25 includes a robot hand 252 supported on a base 251, and the base 251 is supported so as to be movable along a pair of guide rails 253 extending in the X-axis direction. The base 251 has a threaded portion (not shown) that screws onto a ball screw 254 extending in the X-axis direction. When the ball screw 254 is rotated by the driving force of the motor, the base 251 moves in the X-axis direction.

[0038] The second transport mechanism 25 transports the wafer W between the temporary storage table 13 and the sheet cutting table 14 and the wafer holding unit 20 by moving the base 251 in the X-axis direction and operating the robot hand 252. More specifically, the second transport mechanism 25 can receive and transport the wafer W from the temporary storage table 13 before the protective member 32 is formed, and hand it over to the holding table 201 of the wafer holding unit 20. In addition, the second transport mechanism 25 can retrieve the wafer W from the holding table 201 of the wafer holding unit 20 after the protective member 32 has been formed, and transport it to the sheet cutting table 14.

[0039] The protective member forming apparatus 1 is centrally controlled by a control unit 40 (Figure 1). The control unit 40 consists of a processor that performs various processes and a memory that stores various parameters and programs. The memory of the control unit 40 stores a program for executing the liquid resin curing determination method, which will be described later, as part of the control program for the protective member forming apparatus 1.

[0040] The control unit 40 includes a judgment unit 41 as one of its functional blocks. The judgment unit 41 makes a determination of the curing of the liquid resin, which will be described later, based on the detection content of the load detection unit 22. Note that the function of the judgment unit 41 is realized by the operation of the processor, memory, etc. that constitute the control unit 40, and this does not mean that the judgment unit 41 is composed of an independent electronic component. Also, although Figure 1 schematically shows only the connection relationship between the judgment unit 41 and the load detection unit 22, the control unit 40 is also connected to each part of the protective member forming apparatus 1 other than the load detection unit 22 so that signals can be sent and received.

[0041] The formation of a protective member using the protective member forming apparatus 1 configured as described above will now be explained.

[0042] Figure 3 shows the sheet loading process. In the sheet loading process, the sheet transport mechanism 17 clamps the end of the sheet 30 with the clamp section 173 and moves the arm 172 in the X-axis direction, pulling the sheet 30 out from the sheet supply section 171 and transporting it to the protective member forming stage 16. The pulled-out sheet 30 is cut to a predetermined length. The sheet 30 is placed on the sheet support surface 161 of the protective member forming stage 16, and the suction source 162 operates to apply suction force to the suction holes (not shown) of the sheet support surface 161, thereby holding the sheet 30 in place. As a result, the sheet 30 adheres tightly to the sheet support surface 161. At this stage, the area of ​​the sheet 30 on the sheet support surface 161 is larger than the area of ​​the lower surface Wb of the wafer W.

[0043] Figure 4 shows the liquid resin supply process. In the liquid resin supply process, the resin supply nozzle 183 of the resin supply mechanism 18 is positioned above the sheet 30 which has been placed on the sheet support surface 161 by the previous sheet loading process. Then, the dispenser 181 is controlled to send liquid resin 31 to the resin supply nozzle 183, causing the liquid resin 31 to drip from the resin supply nozzle 183 onto the sheet 30. The resin supply nozzle 183 is positioned above the center of the protective member forming stage 16, and the liquid resin 31 dripped from the resin supply nozzle 183 accumulates near the center of the upper surface of the sheet 30 in an area smaller than the area of ​​the wafer W.

[0044] Based on information such as the size of the wafer W, the control unit 40 causes the resin supply mechanism 18 to supply a predetermined amount of liquid resin 31 to the sheet 30, in an amount sufficient to cover the entire lower surface Wb of the wafer W. Once the predetermined amount of liquid resin 31 has been supplied, the resin supply nozzle 183 is rotated to detach it from above the protective member forming stage 16, thus completing the liquid resin supply process.

[0045] Figure 5 shows the state in which the wafer W is held in the wafer holding section 20 by the wafer holding process. In the wafer holding process, the wafer W, before the protective member 32 is formed, is removed from the cassette C1 in the storage space 111 by the first transport mechanism 12 and transported to the temporary storage table 13. On the temporary storage table 13, the orientation and center of the wafer W are detected by the wafer detection section 131. Once the orientation and center of the wafer W are detected, the wafer W is transported to the wafer holding section 20 by the second transport mechanism 25. In the wafer holding section 20, the suction source 205 is operated to apply suction force to the porous member 202, and the upper surface Wa of the wafer W is sucked onto the wafer holding surface 203 and held in place.

[0046] Furthermore, at least a portion of the wafer holding process may be performed in parallel with (simultaneously with) the sheet loading process and the liquid resin supply process.

[0047] When the wafer W held in the wafer holder 20 is positioned opposite the liquid resin 31 on the sheet 30 (Figure 5), the process proceeds to the spreading step shown in Figure 6. In the spreading step, the motor 214 is operated by the lifting mechanism 21 to lower the lifting table 212 and the wafer holder 20 at a predetermined feed speed.

[0048] As the wafer holding unit 20 descends, the lower surface Wb of the wafer W approaches the protective member forming stage 16 and comes into contact with the liquid resin 31. The liquid resin 31 is then pressed by the lower surface Wb of the wafer W, causing it to spread radially across the wafer W. Before contact with the lower surface Wb of the wafer W, the liquid resin 31 is concentrated near the center of the sheet 30 (see Figure 5), and as it is pressed from the wafer W, the liquid resin 31 spreads toward the outer edge of the wafer W (see Figure 6).

[0049] As the wafer holder 20 is lowered and the liquid resin 31 is spread by the lower surface Wb of the wafer W, the load in the Z-axis direction (vertical direction) applied to the lower surface Wb of the wafer W (value of the pressing force from the wafer W to the liquid resin 31) increases. When the liquid resin 31 spreads to the entire lower surface Wb of the wafer W and extends outward from the outer edge of the wafer W, the above load begins to decrease. Such changes in load are detected using the load sensor 221 in the load detection unit 22.

[0050] The detection results from the load detection unit 22 (output signals from each load sensor 221) are input to the control unit 40. The control unit 40 refers to the detection results from the load detection unit 22 and controls the drive of the motor 214 of the lifting mechanism 21 according to the change in load in the Z-axis direction (vertical direction), thereby spreading the liquid resin 31 over the entire lower surface Wb of the wafer W (until it reaches the outer edge of the wafer W).

[0051] Whether or not the liquid resin 31 has spread over the entire lower surface Wb of the wafer W can be determined based on the detection result of the load detection unit 22. Figure 9 is a graph showing the relationship between the change in the height (position in the Z-axis direction) of the wafer holding unit 20 and the load value in the Z-axis direction detected by the load detection unit 22. In Figure 9, the change in the height of the wafer holding unit 20 is shown by the dashed line P, and the change in the load value detected by the load detection unit 22 is shown by the solid line Q. In the graph of Figure 9, the horizontal axis shows the passage of time, the vertical axis for the dashed line P shows the height of the wafer holding unit 20, and the vertical axis for the solid line Q shows the load value.

[0052] Section Pa shows the downward movement of the wafer holder 20 from the start of the spreading process until the lower surface Wb of the wafer W comes into contact with the liquid resin 31 and spreads. When the spreading start point Ta is reached, in which the wafer W begins to press against the liquid resin 31, the wafer holder 20 stops descending (section Pb), and the reaction force from the liquid resin 31 being spread acts on the lower surface Wb of the wafer W, causing the load value to increase (section Qa).

[0053] When the spread liquid resin 31 has spread to the entire lower surface Wb of the wafer W, and the liquid resin 31 extends beyond the outer edge of the wafer W, the load value changes from rising to falling (section Qb). A predetermined value Qc is set and stored in advance as a reference load value corresponding to the completion of the spreading of the liquid resin 31. The predetermined value Qc is set to a value lower than the peak of the load value (the value at the boundary between section Pa and section Pb), and when it is detected that the load value has reached the predetermined value Qc in section Pb, the control unit 40 determines that the liquid resin 31 has covered the entire lower surface Wb of the wafer W.

[0054] When the control unit 40 detects that the downward load value has reached a predetermined value Qc, at the spreading completion determination point Tb, it reverses the operation of the motor 214 of the lifting mechanism 21 to slightly raise the wafer holding section 20 (section Pc). Once the wafer holding section 20 has been raised by a predetermined amount, it stops the operation of the motor 214 to maintain a constant height for the wafer holding section 20 (section Pd).

[0055] Furthermore, when determining the state of the liquid resin 31's spread, the image captured by the imaging unit 24 may be referred to in conjunction with the detection by the load detection unit 22.

[0056] Once the spreading process is complete and the entire lower surface Wb of the wafer W is covered with the liquid resin 31, the curing process shown in Figure 7 is performed. In the curing process, ultraviolet UV light of sufficient intensity to cure the liquid resin 31 is irradiated from the ultraviolet irradiation section 231 of the curing mechanism 23 toward the sheet support surface 161. The ultraviolet UV light emitted from the ultraviolet irradiation section 231 passes through the light-transmitting protective member forming stage 16 and the sheet 30 to reach the liquid resin 31, curing the liquid resin 31, which is an ultraviolet-curable resin. When the liquid resin 31 is judged to be sufficiently cured, the irradiation of ultraviolet UV light from the curing mechanism 23 is terminated.

[0057] The method for determining the curing of the liquid resin 31 will be explained with reference to Figure 9. At the curing start point Tc, which is the point when the wafer holding section 20 has finished rising in section Pc, the control unit 40 starts irradiating with ultraviolet UV light from the ultraviolet irradiation section 231 of the curing mechanism 23. The wafer holding section 20, which holds the wafer W, maintains a constant height of the wafer W in section Pd, which starts from the curing start point Tc. Meanwhile, the liquid resin 31 gradually hardens in response to the ultraviolet UV irradiation from the curing start point Tc, and shrinks as it hardens. When the liquid resin 31 shrinks, the load value on the lower surface Wb of the wafer W detected by the load detection section 22 decreases (section Qd).

[0058] The load value is "0" when no external force in the Z-axis direction is acting on the wafer W held by the wafer holder 20. In the positive load region of section Qd, where the load value is greater than 0, it means that a force remains that pushes the lower surface Wb of the wafer W upward. In the negative load region of section Qd, where the load value is less than 0, it means that the force generated when the liquid resin 31 contracts is acting to pull the wafer W downward away from the wafer holder 20.

[0059] A threshold value Qe is pre-set and stored as the value indicating the completion of curing of the liquid resin 31 in the load value in interval Qd. The determination unit 41 of the control unit 40 determines that the liquid resin 31 has cured when it detects that the load value has fallen below the threshold value Qe after the curing start point Tc. The point in time when this determination is made is defined as the curing completion determination point Td.

[0060] In this embodiment, a threshold Qe is set in the negative load region within the interval Qd described above. In other words, the determination unit 41 does not determine that the liquid resin 31 has hardened while the lower surface Wb of the wafer W is subjected to an upward pushing load, but rather determines that the liquid resin 31 has hardened only after the liquid resin 31 has contracted to the point where the lower surface Wb of the wafer W is pulled downward.

[0061] Unlike this embodiment, it is also possible to set the threshold Qe to the positive load region or the state where the load value is 0 within the interval Qd. The threshold Qe should be a load value that reflects the state in which the liquid resin 31 has sufficiently hardened over the entire lower surface Wb of the wafer W.

[0062] As described above, the determination unit 41 makes a determination of curing in the liquid resin 31. Upon detection of the threshold Qe by the load detection unit 22 (curing completion determination point Td), it is determined that the liquid resin 31 that has spread over the entire lower surface Wb of the wafer W has sufficiently cured.

[0063] In the determination method shown in Figure 9, it is possible to obtain the load value (Q) as the average value of the values ​​detected by multiple load sensors 221. Alternatively, it is possible to individually determine whether the values ​​detected by multiple load sensors 221 have reached a threshold (Qe). By individually evaluating and determining the detection results of multiple load sensors 221, it is also possible to obtain information such as the bias in the curing progress of the liquid resin 31 within the area of ​​the lower surface Wb of the wafer W.

[0064] When the liquid resin 31 hardens, the hardened resin (original liquid resin 31) and the sheet 30 form a protective member 32 that covers the lower surface Wb of the wafer W. When it is determined that the liquid resin 31 has hardened and the formation of the protective member 32 is complete, the irradiation of ultraviolet UV from the ultraviolet irradiation unit 231 of the hardening mechanism 23 is terminated. At the same time, the operation of the suction source 162 is stopped, and the suction holding of the sheet 30 to the sheet support surface 161 of the protective member formation stage 16 is released.

[0065] Next, the motor 214 is operated by the lifting mechanism 21 to raise the lifting table 212 and the wafer holding unit 20, and the wafer W, which has the protective member 32 formed on it, is transferred from the wafer holding unit 20 to the robot hand 252 of the second transfer mechanism 25. During this transfer, the communication between the wafer holding surface 203 of the wafer holding unit 20 and the suction source 205 is cut off, releasing the suction holding of the wafer W by the wafer holding unit 20. Specifically, by closing the on / off valve (not shown) provided in the suction passage 204 or stopping the operation of the suction source 205, the suction force is no longer applied to the wafer holding surface 203. Once the suction holding on the wafer holding unit 20 side is released, it becomes possible to transfer the wafer W to the robot hand 252 positioned below the wafer holding unit 20.

[0066] The second transport mechanism 25 transports the wafer W received from the wafer holding unit 20 to the sheet cutting table 14. Using the sheet cutter 141, the excess sheet 30 is cut along the outer shape of the wafer W placed on the sheet cutting table 14.

[0067] Next, the first transport mechanism 12 transports the wafer W from the sheet cutting table 14 to the cassette storage section 11, and places it in the cassette C2 in the storage space 112.

[0068] As described above, the formation of the protective member 32 on the wafer W in the protective member forming apparatus 1 is completed. The wafer W on which the protective member 32 has been formed is then transported to a processing apparatus separate from the protective member forming apparatus 1 for further processing.

[0069] For example, the wafer W is transported to a grinding machine, and the side opposite to the protective member 32 (the top surface Wa) is ground. During grinding in the grinding machine, the protective member 32 is pressed against the holding table of the grinding machine. The protective member 32, which has a predetermined thickness and is hardened, can withstand the pressure and allow the wafer W to be ground stably.

[0070] Figure 8 shows a modified example of the curing process in the protective member forming apparatus 1. In this modified example, the liquid resin 33 is a thermosetting resin that hardens in a predetermined temperature range, and a heater 261 is provided as a curing mechanism 26 that hardens the liquid resin 33 by applying external stimuli. The heater 261 is located inside the holding table 201 of the wafer holding section 20 and is heated by power supplied from the power supply 262.

[0071] In this modified example, since ultraviolet light is not irradiated from below the protective member forming stage 16, the protective member forming stage 16 and the sheet 30 do not need to be made of light-transmitting material.

[0072] As shown in Figure 8, when the liquid resin 33 is spread over the entire lower surface Wb of the wafer W and heated by the heater 261 of the curing mechanism 26, heat is transferred from the holding table 201 through the wafer W to the liquid resin 33, causing the liquid resin 33 to harden. In other words, heat transfer to the liquid resin 33 acts as an external stimulus. The hardening of the liquid resin 33 can be determined by the determination method described above.

[0073] Specifically, heating by the heater 261 is started at the curing start point Tc in Figure 9. The liquid resin 33 gradually hardens due to the heating from the curing start point Tc and shrinks as it hardens. As the liquid resin 33 shrinks, the load value on the lower surface Wb of the wafer W detected by the load detection unit 22 decreases (section Qd).

[0074] The determination unit 41 of the control unit 40 determines that the liquid resin 33 has hardened (hardening completion determination point Td) if it detects that the load value has fallen below a preset threshold Qe after the hardening start point Tc. When the hardening completion determination point Td is reached, heating to the heater 261 is terminated. As a result, a protective member 34 consisting of the hardened resin (original liquid resin 33) and the sheet 30 is formed on the lower surface Wb side of the wafer W.

[0075] The processing after the curing process is the same as in the previous embodiment. The wafer W, on which the protective member 34 has been formed, is transferred from the wafer holding unit 20 to the second transport mechanism 25 and then transported to the sheet cutting table 14. There, the excess sheet 30 is cut along the outer shape of the wafer W using the sheet cutter 141. Furthermore, the wafer W from which the excess sheet 30 has been cut is transported from the sheet cutting table 14 to the cassette storage unit 11 using the first transport mechanism 12 and stored in the cassette C2 in the storage space 112.

[0076] As described above, the liquid resin curing determination method and protective member forming apparatus in this embodiment focuses on the fact that the vertical load value acting on the wafer W changes due to the shrinkage when the liquid resins 31 and 33 cure. Therefore, it is equipped with a load detection unit 22 that detects the vertical load acting on one surface (bottom surface Wb) of the wafer W. When the load detected by the load detection unit 22 becomes smaller than a preset threshold Qe, it is determined that the liquid resins 31 and 33 have cured.

[0077] In this way, instead of relying solely on the control of the UV irradiation time by the curing mechanism 23 and the heating time by the curing mechanism 26, the curing judgment is made based on the change in load value based on the actual curing status of the liquid resins 31 and 33. This prevents curing defects (insufficient curing) of the liquid resins 31 and 33, and allows for the reliable formation of protective members 32 and 34 with high precision.

[0078] For example, if the ultraviolet irradiation section 231 of the curing mechanism 23 or the heater 261 of the curing mechanism 26 deteriorates, even if ultraviolet irradiation or heating is performed for a preset time, the curing of the liquid resins 31 and 33 may become insufficient. However, according to this embodiment, the irradiation or heating can be controlled to continue (extend) until the curing determination by the determination unit 41 is made.

[0079] Furthermore, even if there are variations in the curing progress due to differences in the batches of liquid resins 31 and 33, curing can be performed based on the determination of curing by the determination unit 41, thereby appropriately curing in response to such variations. For example, if ultraviolet irradiation or heating is performed even though the liquid resins 31 and 33 have actually cured, time loss and energy loss will occur. However, according to this embodiment, unnecessary ultraviolet irradiation or heating after the liquid resins 31 and 33 have cured can be prevented, and the external stimuli applied to the liquid resins 31 and 33 can be optimized.

[0080] Furthermore, if the curing determination by the judgment unit 41 is not completed (curing cannot be detected) even after a preset time has elapsed since the start of ultraviolet irradiation or heating, it is possible to determine that a malfunction of the curing mechanism 23 or curing mechanism 26, a defect or error in the liquid resins 31 and 33 (for example, a mix-up of ultraviolet curing resin and thermosetting resin), or other setting errors have occurred. For example, if a time count is performed from the curing start point Tc (Figure 9) and the threshold Qe is not detected after a predetermined time has elapsed, the control unit 40 may use a notification unit such as a display, speaker, or lamp provided in the protective member forming apparatus 1 to notify the operator that some kind of error has occurred in the curing process of the liquid resins 31 and 33.

[0081] Furthermore, the embodiments of the present invention are not limited to the embodiments and modifications described above, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Moreover, if the technical idea of ​​the present invention can be realized in a different way by advances in the art or by other derived arts, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention. [Industrial applicability]

[0082] As described above, the liquid resin curing determination method and protective member forming apparatus of the present invention have the effect of being able to reliably determine when the liquid resin has cured, and are particularly useful in the manufacturing field of semiconductors and the like, which includes a process of forming a protective member on one side of a wafer. [Explanation of symbols]

[0083] 1: Protective member forming apparatus 10: External enclosure 11: Cassette storage compartment 12: First conveying mechanism 13: Temporary Table 14: Sheet cutting table 15: Base 16: Protective member forming stage 17: Sheet transport mechanism 18:Resin supply mechanism 20: Wafer holding section 21: Lifting mechanism 22: Load detection unit 23:Curing mechanism 25: Second conveying mechanism 26:Curing mechanism 30: Sheet 31: Liquid resin 32: Protective component 33: Liquid resin 34: Protective component 40: Control Unit 41:Judgment Department 183: Resin supply nozzle 201: Holding Table 203: Wafer holding surface 221: Load sensor 231: UV irradiation area 261: Heater 262 :Power supply P: Change in the height of the wafer holder Q: Changes in load values ​​detected by the load detection unit Qe: threshold Ta: Starting point for spreading Tb: Point of judgment for completion of expansion Tc: Hardening start point Td: Curing completion judgment point UV: Ultraviolet light W: wafer Wa: Top surface Wb: Bottom surface (one side)

Claims

1. A method for determining the hardening of a liquid resin, which involves applying an external stimulus to a liquid resin spread over the entire surface of one side of a wafer and determining that the liquid resin has hardened, After spreading the liquid resin over the entire surface of one side of the wafer, move the wafer away from the liquid resin, reducing the load on the underside of the wafer and the liquid resin to near zero, and then apply an external stimulus to the liquid resin. A method for determining the curing of a liquid resin, which involves detecting a vertical load on one side of the wafer so as to detect shrinkage when the liquid resin hardens, and determining that the liquid resin has hardened when the load becomes smaller than a preset negative threshold, causing the bottom surface of the wafer to be pulled downwards.

2. A protective member forming apparatus comprising a sheet with an area larger than one side of the wafer and a liquid resin that hardens upon external stimuli between the wafer and the wafer, spreading the liquid resin that hardens upon external stimuli over the entire surface of one side of the wafer, and then applying external stimuli to harden the resin and form a protective member consisting of the sheet, A curing mechanism that applies external stimuli to the liquid resin, A load detection unit that detects a load perpendicular to one side of the wafer, A determination unit determines that the liquid resin has hardened when the load detected by the load detection unit becomes smaller than a preset negative threshold value, causing the lower surface of the wafer to be pulled downwards. A control unit stops moving the wafer towards the liquid resin, and when the liquid resin is spread over the entire surface of one side of the wafer, and the load detected by the load detection unit begins to decrease as the load rises between the bottom surface of the wafer and the liquid resin and reaches a predetermined value, moves the wafer away from the liquid resin, thereby bringing the load detected by the load detection unit closer to zero. A protective member forming apparatus comprising:

3. A method for forming a protective member that protects the entire surface of one side of a wafer, A liquid resin supply process that supplies a liquid resin that hardens upon external stimuli to a sheet, A spreading step in which the liquid resin is pressed with the wafer held in the holding part and the liquid resin is spread over the entire surface of one side of the wafer, The process includes a curing step in which, once the liquid resin has been spread over the entire surface of one side of the wafer during the spreading step, the movement of the holding part is stopped, the load on the lower surface of the wafer and the liquid resin begins to decrease and reaches a predetermined value, the wafer is moved in a direction away from the liquid resin to reduce the load on the lower surface of the wafer and the liquid resin to near zero, and then the liquid resin is cured. The curing process includes a determination step in which, when the load detected by the load detection unit becomes smaller than a preset negative threshold value, the lower surface of the wafer is pulled downwards, and it is determined that the liquid resin has cured. A method for forming a protective member.

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