Method for forming protective member

Abstract

The present invention provides a method for forming a protective component, which can well identify that the resin has become liquid when the resin is made liquid to form the protective component. The method for forming a protective component forms the protective component on one surface of a wafer, wherein the method for forming a protective component includes the following resin state identification process: heating the thermoplastic resin in contact with one surface of the wafer, and transmitting ultrasonic vibration between the resin loading surface of the carrier and the wafer holding surface, and identifying whether the thermoplastic resin between one surface of the wafer held by the wafer holding surface and the resin loading surface has been integrated. When it is identified that it has been integrated, the thermoplastic resin is pushed away on the entire surface of one surface of the wafer, and then the thermoplastic resin is cooled and hardened.

Description

Technical Field

[0001] The present invention relates to a method for forming a protective member. Background Art

[0002] In the technology disclosed in Patent Document 1, a protective member is formed on one surface of a raw cut wafer using a resin. The wafer is held through the protective member by a chuck table, and the other surface of the wafer is ground. Thereby, the undulations of the wafer are removed, and the thickness of the wafer is uniformly shaped.

[0003] The formation of the protective member is performed as follows, for example. First, a sheet is disposed on a stage. Liquid resin is supplied onto the sheet. The liquid resin is pushed away by one surface of the wafer. Thereby, the liquid resin is pushed away over the entire surface of one surface of the wafer. Then, the liquid resin is hardened.

[0004] The liquid resin is sucked up from a container filled with the liquid resin by a pump and supplied onto the sheet on the stage. Since the container of the liquid resin is heavy, the replacement operation becomes a burden on the operator. As a countermeasure, there is a technology using solid granular resin.

[0005] In this technology, the granular resin is melted into a liquid state on the stage and pushed away in a plate shape by one surface of the wafer. The resin is cooled and hardened. Thereby, a plate-shaped protective member can be formed on one surface of the wafer.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-168565

[0007] In the above method for forming a protective member using solid granular resin, the melted resin is clamped between the stage and the wafer. Therefore, it is difficult to judge whether the solid resin has melted. As a result, sometimes the insufficient liquid resin including the resin that has not been completely melted is pushed away by the wafer. In this case, it is difficult to form a protective member with a uniform thickness, and the granular resin and the time spent on the liquefaction of the resin may be wasted. Summary of the Invention

[0008] Accordingly, an object of the present invention is to provide a method for forming a protective member, which can favorably recognize that the resin has become a liquid state when forming the protective member by making the solid resin into a liquid state.

[0009] According to the present invention, there is provided a method for forming a protective member on one surface of a wafer. The method for forming the protective member includes the following steps: a resin supply step of disposing a plurality of granular thermoplastic resins on a resin placement surface of a stage; a wafer holding step of holding the other surface of the wafer by a wafer holding surface of a wafer holding unit; a contact step of moving the wafer holding unit and the stage in a direction of relative approach using a vertical movement mechanism, so that one surface of the wafer held by the wafer holding unit contacts the granular thermoplastic resin; a resin state identification step of heating the granular thermoplastic resin in contact with one surface of the wafer and propagating ultrasonic vibration between the resin placement surface and the wafer holding surface to identify whether the thermoplastic resin clamped between one surface of the wafer held by the wafer holding surface and the resin placement surface has been integrated; a pushing step of pushing, by the wafer, the thermoplastic resin identified as integrated in the resin state identification step over the entire surface of one surface of the wafer; and a hardening step of cooling and hardening the pushed thermoplastic resin. The method for forming the protective member forms a protective member that protects the entire surface of one surface of the wafer.

[0010] In the method for forming a protective member of the present invention, in the resin state identification step, it is identified whether the thermoplastic resin clamped between one surface of the wafer and the resin placement surface has been sufficiently melted and integrated. And when it is identified that integration has occurred, the pushing step is performed, and the thermoplastic resin is pushed over the entire surface of one surface of the wafer by the wafer. Therefore, in this forming method, it is possible to suppress the wafer from pressing and pushing the insufficiently melted thermoplastic resin. In addition, it is possible to suppress the wafer from being damaged by pressing the insufficiently melted thermoplastic resin. Thereby, it is possible to make the thickness of the protective member made of thermoplastic resin formed on one surface of the wafer substantially uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a cross-sectional view showing the structure of a resin protective member forming apparatus.

[0012] Figure 2 It is a cross-sectional view showing the resin supply step in a resin protective member forming apparatus.

[0013] Figure 3 It is a cross-sectional view showing the wafer holding step in a resin protective member forming apparatus.

[0014] Figure 4 It is a cross-sectional view showing the wafer contact step in a resin protective member forming apparatus.

[0015] Figure 5 It is a cross-sectional view showing the heating step and the resin state identification step in a resin protective member forming apparatus.

[0016] Figure 6 It is a graph showing an example of ultrasonic vibration received by an ultrasonic receiver.

[0017] Figure 7 It is a cross-sectional view showing a pushing operation in a resin protection member forming apparatus.

[0018] Figure 8 It is a cross-sectional view showing cooling (hardening) in a resin protection member forming apparatus.

[0019] Figure 9 It is a cross-sectional view showing a separation process in a resin protection member forming apparatus.

[0020] Figure 10 It is a cross-sectional view showing a wafer unloading process in a resin protection member forming apparatus.

[0021] Reference Numeral Explanation

[0022] 1: Resin protection member forming apparatus; 2: Vacuum forming chamber; 3: Cover; 5: Cover opening / closing mechanism; 7: Vacuum pump; 10: Wafer holding unit; 12: Wafer holding table; 13: Wafer holding surface; 14: Air supply source; 15: Ventilation path; 16: Suction source; 17: Ultrasonic transmitting unit; 18: Ultrasonic oscillator; 20: Stage; 22: Resin placement table; 23: Resin placement surface; 24: Peltier element; 24a: Upper surface; 24b: Lower surface; 25: First power line; 26: Second power line; 27: Switch; 28: DC power supply; 33: Ultrasonic receiver; 34: Ultrasonic receiving unit; 30: Vertical movement mechanism; 60: Load detector; 40: Wafer transfer mechanism; 50: Resin transfer mechanism; 70: Control unit; S: Molten resin layer; W: Wafer; Wb: Second surface. Detailed Description of the Embodiment

[0023] Figure 1 The resin protection member forming apparatus 1 shown in the present embodiment melts the solid granular thermoplastic resin P placed on the resin placement surface 23 of the stage 20, and hardens the thermoplastic resin pushed open on the entire surface of one surface of the wafer W to form a protection member. The material of the thermoplastic resin P is, for example, polyolefin. For example, fluorine coating is applied to the resin placement surface 23 so that the placed thermoplastic resin can be easily peeled off.

[0024] The resin protection member forming apparatus 1 includes: a wafer holding unit 10 that holds the wafer W through the wafer holding surface 13 in the vacuum forming chamber 2; a stage 20 that has a resin placement surface 23 for placing the granular thermoplastic resin P; and a vertical movement mechanism (vertical action mechanism) 30.

[0025] The vacuum forming chamber 2 is the housing of the resin protection component forming device 1 capable of making the interior a vacuum, and it has an opening 4, a cover 3 capable of covering the opening 4, a cover opening / closing mechanism 5 for opening and closing the cover 3, and a vacuum pump 7 for making the interior of the vacuum forming chamber 2 a vacuum.

[0026] The wafer holding unit 10 has: a support post 11 that extends through the upper surface of the vacuum forming chamber 2; and a wafer holding table 12 that is provided at the lower end of the support post 11 and is disposed inside the vacuum forming chamber 2. The lower surface of the wafer holding table 12 becomes a wafer holding surface 13 for sucking and holding the wafer W. In addition, a vacuum seal 2a for maintaining the vacuum inside the vacuum forming chamber 2 is provided at the through portion of the support post 11 on the upper surface of the vacuum forming chamber 2.

[0027] An air passage 15 connected to an air supply source 14 and a suction source 16 is provided in the support post 11 and the wafer holding table 12. The wafer holding surface 13 in the wafer holding table 12 is configured to be selectively communicated with the air supply source 14 and the suction source 16 via the air passage 15. The wafer holding unit 10 can suck and hold the wafer W through the wafer holding surface 13 communicated with the suction source 16.

[0028] In addition, in the wafer holding table 12 of the wafer holding unit 10, an ultrasonic oscillator 18 is provided near the wafer holding surface 13. The ultrasonic oscillator 18 is connected to, for example, an ultrasonic transmitting unit 17 having a high-frequency power supply. The ultrasonic oscillator 18 oscillates ultrasonic waves using the high-frequency power from the ultrasonic transmitting unit 17.

[0029] The stage 20 has: a support post 21 that extends through the bottom surface of the vacuum forming chamber 2; and a resin mounting table 22 that is provided at the upper end of the support post 21 and is disposed inside the vacuum forming chamber 2. In addition, the upper surface of the resin mounting table 22 becomes a resin mounting surface 23 for mounting the thermoplastic resin P.

[0030] The resin mounting surface 23 is arranged to face the wafer holding surface 13 of the wafer holding unit 10. In addition, a vacuum seal 2b for maintaining the vacuum inside the vacuum forming chamber 2 is provided at the through portion of the support post 21 on the bottom surface of the vacuum forming chamber 2.

[0031] In addition, in the resin mounting table 22 of the stage 20, an ultrasonic receiver 33 is provided near the resin mounting surface 23. The ultrasonic receiver 33 receives the ultrasonic vibration propagated to itself, converts it into a voltage, and transmits it to the ultrasonic receiving unit 34.

[0032] In addition, the resin protection component forming device 1 includes a wafer transfer mechanism 40 and a resin transfer mechanism 50. The wafer transfer mechanism 40 and the resin transfer mechanism 50 are transfer components such as robotic arms. These wafer transfer mechanism 40 and resin transfer mechanism 50 can be different components or a common single component.

[0033] The wafer transfer mechanism 40 transfers the wafer W from the outside to the vacuum forming chamber 2. The wafer transfer mechanism 40 can dispose the wafer W via the opening 4 at a position in the vacuum forming chamber 2 that faces the wafer holding surface 13 of the wafer holding unit 10. In the wafer holding unit 10, the wafer W thus disposed can be attracted and held by the wafer holding surface 13 communicating with the suction source 16.

[0034] The resin transfer mechanism 50 transfers a plurality of granular thermoplastic resins P from the outside to the resin protection component forming device 1. The resin transfer mechanism 50 places the granular thermoplastic resins P via the opening 4 of the vacuum forming chamber 2 on the resin placement surface 23 of the stage 20 in the vacuum forming chamber 2. Additionally, a ring-shaped convex portion can be formed on the outer periphery of the resin placement surface 23 so that the granular thermoplastic resins P do not fall off the resin placement surface 23.

[0035] The vertical movement mechanism 30 is disposed on the upper surface of the vacuum forming chamber 2 and is connected to the support columns 11 of the wafer holding unit 10. The vertical movement mechanism 30 relatively moves the wafer holding unit 10 and the stage 20 in the vertical direction perpendicular to the resin placement surface 23, i.e., the Z-axis direction. In the present embodiment, the vertical movement mechanism 30 moves the support columns 11 of the wafer holding unit 10 in the Z-axis direction. That is, the vertical movement mechanism 30 is configured to move the wafer holding unit 10 relative to the fixed stage 20 along the Z-axis direction.

[0036] Specifically, the vertical movement mechanism 30 includes: an arm 31, which is connected to the support column 11 and extends in the horizontal direction; a drive rod 32, which is connected to the arm 31 and extends along the Z-axis direction; and a sensor 35, which detects the movement distance. The drive rod 32 is moved up and down by a drive source (not shown), so that the arm 31 and the wafer holding unit 10 (support column 11) connected to the arm 31 move up and down along the Z-axis direction. The movement distance of the wafer holding unit 10 is detected by the sensor 35.

[0037] In addition, the resin protection component forming device 1 includes a load detector 60. The load detector 60 is connected to the support column 11 of the wafer holding unit 10 via the vertical movement mechanism 30. The load detector 60 detects the load applied to the wafer holding unit 10 when the wafer holding unit 10 and the stage 20 are in contact with each other with the wafer W and the thermoplastic resin P therebetween (i.e., the force with which the wafer W presses the thermoplastic resin P).

[0038] In addition, the stage 20 of the present embodiment has a Peltier element 24 inside. The Peltier element 24 is an example of a temperature adjustment device disposed on the stage 20. The Peltier element 24 has, for example, a flat plate shape and is disposed in parallel with the resin placement surface 23 near the resin placement surface 23 of the resin placement stage 22 of the stage 20. The Peltier element 24 is parallel to the resin placement surface 23 and has an upper surface 24a close to the resin placement surface 23 and a lower surface 24b away from the resin placement surface 23.

[0039] In addition, one ends of a first power line 25 and a second power line 26 that are wound around the support posts 21 and inside the resin placement stage 22 are attached to both ends of the Peltier element 24. The other ends of the first power line 25 and the second power line 26 are connected to a DC power supply 28 via a switch 27.

[0040] The DC power supply 28 is a power supply that supplies a DC current to the Peltier element 24. The switch 27 has a function of connecting the DC power supply 28 to the Peltier element 24 via the first power line 25 and the second power line 26 and a function of switching the direction of the DC current flowing from the DC power supply 28 to the Peltier element 24 via the first power line 25 and the second power line 26.

[0041] That is, the switch 27 is configured to switch the direction of the DC current supplied to the Peltier element 24 to a first direction that heats the upper surface 24a of the Peltier element 24 and a second direction that cools the upper surface 24a of the Peltier element 24, and the second direction is a direction opposite to the first direction. In addition, regarding the lower surface 24b of the Peltier element 24, it is cooled when the DC current flows in the first direction and heated when the DC current flows in the second direction.

[0042] In addition, the resin protection member forming device 1 has a control unit 70 that controls each component of the resin protection member forming device 1, and the control unit 70 includes a computer. The control unit 70 controls each component of the resin protection member forming device 1 described above to form a protection member on the entire surface of one surface of the wafer W.

[0043] Next, the formation operation of the protection member with respect to the wafer W in the resin protection member forming device 1 will be described.

[0044] First, the control unit 70 controls the cover opening / closing mechanism 5 to open the cover 3 of the vacuum forming chamber 2 and expose the opening 4. And the control unit 70 moves the resin transfer mechanism 50 holding a plurality of granular thermoplastic resins P in the -X direction, so as to transfer the thermoplastic resin P from the exposed opening 4 into the vacuum forming chamber 2. In addition, the control unit 70 controls the resin transfer mechanism 50 as Figure 2As shown, a plurality of thermoplastic resins P are arranged (placed) in a planar manner at substantially uniform intervals on the resin placement surface 23 of the stage 20 (resin supply step).

[0045] Next, the control unit 70 causes Figure 1 the suction source 16 shown to communicate with the wafer holding surface 13 of the wafer holding unit 10. As a result, the wafer holding surface 13 becomes a negative pressure. In addition, the control unit 70 causes the wafer transfer mechanism 40 holding the wafer W to move in the -X direction, thereby loading the wafer W from the exposed opening 4 into the vacuum forming chamber 2 and arranging it at a position facing the wafer holding surface 13. In addition, as Figure 3 shown, the control unit 70 sucks and holds the first surface (the other surface) Wa of the wafer W through the wafer holding surface 13. As a result, the wafer W is arranged above the thermoplastic resin P placed on the resin placement surface 23 with the second surface (one surface) Wb facing the thermoplastic resin P (wafer holding step).

[0046] Next, the control unit 70 controls Figure 1 the cover opening / closing mechanism 5 shown to close the cover 3 of the vacuum forming chamber 2 and seal the opening 4.

[0047] The control unit 70 controls the vertical movement mechanism 30 to move the wafer holding unit 10 downward along the Z-axis direction. As a result, as Figure 4 shown, the second surface Wb of the wafer W held by the wafer holding surface 13 of the wafer holding unit 10 contacts the plurality of thermoplastic resins P held by the resin placement surface 23 of the stage 20 (wafer contact step).

[0048] In this way, the control unit 70 uses the vertical movement mechanism 30 to relatively move the wafer holding unit 10 and the stage 20 in the approaching direction, so that the second surface Wb of the wafer W held by the wafer holding unit 10 contacts (presses with a relatively weak force) the granular thermoplastic resin P held by the resin placement surface 23. In this state, the control unit 70 controls the vacuum pump 7 to perform vacuum suction on the inside of the vacuum forming chamber 2.

[0049] In addition, in this state, when the air pressure inside the vacuum forming chamber 2 becomes below a specified value, the control unit 70 controls Figure 1 the switch 27 shown to connect the DC power supply 28 to the Peltier element 24 via the first power line 25 and the second power line 26. And the control unit 70 controls the switch 27 to set the direction of the DC current from the DC power supply 28 as shown by the arrow D1 in Figure 5 the first direction for heating the upper surface 24a of the Peltier element 24 (indicated by "h" in the figure).

[0050] In this way, while the control unit 70 presses the thermoplastic resin P through the second surface Wb of the wafer W, a direct current is caused to flow in the first direction, thereby heating the upper surface 24a of the Peltier element 24, heating the resin mounting surface 23 and the thermoplastic resin P on the resin mounting surface 23, and melting the thermoplastic resin P (heating step). In addition, at this time, the lower surface 24b of the Peltier element 24 is cooled (indicated by "c" in the figure).

[0051] In addition, the control unit 70 controls the ultrasonic wave transmitting unit 17 to oscillate ultrasonic waves from the ultrasonic oscillator 18. The ultrasonic waves oscillated from the ultrasonic oscillator 18 propagate between the wafer holding surface 13 and the resin mounting surface 23 (i.e., through the thermoplastic resin P). And the control unit 70 obtains a voltage corresponding to the amplitude of the ultrasonic vibration received by the ultrasonic wave receiver 33 via the ultrasonic wave receiving unit 34. The control unit 70 calculates the amplitude amount of the ultrasonic vibration received by the ultrasonic wave receiver 33 based on the obtained voltage. The control unit 70 determines whether the thermoplastic resin P clamped between the wafer holding surface 13 and the resin mounting surface 23 has become liquid and integrated (whether it has melted sufficiently) based on the calculated amplitude amount of the ultrasonic vibration (resin state identification step).

[0052] In Figure 6 a graph showing the ultrasonic vibration received by the ultrasonic wave receiver 33 is shown. In this graph, the vertical axis represents the amplitude amount (A), and the horizontal axis represents the time (T). When the thermoplastic resin P has not sufficiently become liquid and not integrated, the ultrasonic vibration received by the ultrasonic wave receiver 33 has a relatively small amplitude as shown by the dashed line R0 in Figure 6 . On the other hand, when the thermoplastic resin P has sufficiently become liquid and integrated, the ultrasonic vibration received by the ultrasonic wave receiver 33 has a relatively large amplitude as shown by the solid line R1 in Figure 6 .

[0053] Therefore, for example, when the amplitude of the ultrasonic vibration received by the ultrasonic wave receiver 33 becomes equal to or greater than a specified value, the control unit 70 determines that the thermoplastic resin P clamped between the wafer holding surface 13 and the resin mounting surface 23 has melted and integrated (liquefied).

[0054] When the control unit 70 determines that the thermoplastic resin P clamped between the wafer holding surface 13 and the resin mounting surface 23 has melted and integrated, it controls the vertical movement mechanism 30 to press the integrated thermoplastic resin P more strongly through the second surface Wb of the wafer W. In this way, the control unit 70 pushes the thermoplastic resin P integrated between the resin mounting surface 23 and the second surface Wb of the wafer W over the entire surface of the second surface Wb by the wafer W. Thus, as Figure 7As shown, a molten resin layer S formed of a thermoplastic resin P pushed away by melting is formed so as to cover the entire surface of the second surface Wb of the wafer W (pushing step).

[0055] Then, the control unit 70 controls the switch 27 (refer to Figure 1 ) so that a direct current from the direct current power supply 28 flows in a second direction opposite to the first direction for cooling the upper surface 24a of the Peltier element 24 as indicated by the arrow D2 in Figure 8 . Thereby, the control unit 70 cools the upper surface 24a of the Peltier element 24 while pressing the molten resin layer S through the second surface Wb of the wafer W. By cooling the upper surface 24a in this way, the control unit 70 cools the resin mounting surface 23 and the molten resin layer S on the resin mounting surface 23, causing the molten resin layer S to harden. Thereby, a protective member Sa (refer to Figure 9 ) formed of the hardened molten resin layer S is formed on the entire surface of the second surface Wb of the wafer W (cooling (hardening) step). In addition, at this time, the lower surface 24b of the Peltier element 24 is heated.

[0056] Next, the control unit 70 controls the switch 27 to disconnect the direct current power supply 28 from the Peltier element 24. And the control unit 70 controls the vertical movement mechanism 30 shown in Figure 1 to move the wafer holding unit 10 upward in the Z-axis direction and separate it from the stage 20 (resin mounting surface 23) as shown in Figure 9 . That is, the control unit 70 separates the protective member Sa formed on the second surface Wb of the wafer W from the resin mounting surface 23. Thereby, the control unit 70 can hold the wafer W having the protective member Sa formed on the second surface Wb by the wafer holding surface 13 of the wafer holding unit 10 (separation step).

[0057] Next, the control unit 70 stops the vacuum pump 7 shown in Figure 1 , and controls the cover opening / closing mechanism 5 to open the cover 3 of the vacuum forming chamber 2, exposing the opening 4. Thereby, the vacuum in the vacuum forming chamber 2 is broken.

[0058] In addition, as shown in Figure 10 , the control unit 70 disposes the wafer transfer mechanism 40 to face the wafer holding surface 13 of the wafer holding unit 10 and makes contact with the protective member Sa covering the second surface Wb of the wafer W. In addition, the control unit 70 connects the wafer holding surface 13 of the wafer holding unit 10 to the air supply source 14. Thereby, the adsorption of the wafer W by the wafer holding surface 13 is released, and the wafer W is held by the wafer transfer mechanism 40.

[0059] Further, the control unit 70 moves the wafer W in the +X direction as indicated by the arrow E through the wafer transfer mechanism 40, and discharges it to the outside of the vacuum forming chamber 2 through the opening 4 (wafer discharge process). Further, the wafer transfer mechanism 40 may hold the first surface Wa of the wafer W.

[0060] As described above, in the present embodiment, in the resin state identification process, ultrasonic vibration is propagated between the resin placement surface 23 and the wafer holding surface 13 to identify whether the thermoplastic resin P sandwiched between the second surface Wb of the wafer W held by the wafer holding surface 13 and the resin placement surface 23 is sufficiently melted and integrated. And when it is identified that they are already integrated, the pushing process is performed, and the thermoplastic resin P is pushed away over the entire surface of the second surface Wb of the wafer W by the wafer W. Therefore, in the present embodiment, it is possible to suppress the wafer W from pressing and pushing the insufficiently melted thermoplastic resin P. In addition, it is possible to suppress the wafer W from being damaged by pressing the insufficiently melted thermoplastic resin P. Thereby, the thickness of the protective member Sa formed of the thermoplastic resin P on the second surface Wb of the wafer W can be made substantially uniform.

[0061] In addition, in the present embodiment, in the heating process, the upper surface 24a of the Peltier element 24 is heated, so that the resin placement surface 23 and the thermoplastic resin P placed thereon are heated to obtain a molten resin layer S. At this time, the lower surface 24b of the Peltier element 24 is cooled, so that in the next cooling (hardening) process, the cooling effect of cooling the resin placement surface 23 can be improved. Therefore, the time (the time of the cooling (hardening) process) for cooling and hardening the molten resin layer S to form the protective member Sa on the second surface Wb of the wafer W can be shortened.

[0062] In addition, in the present embodiment, in the heating process and the cooling process, a direct current is passed through the Peltier element 24 to heat or cool the upper surface 24a of the Peltier element 24, thereby heating the granular thermoplastic resin P or cooling the molten resin layer S. However, the structure for implementing such heating and cooling is not limited to the Peltier element 24. Other temperature adjustment devices arranged on the stage 20 or the wafer holding unit 10 may be used instead of the Peltier element 24.

[0063] In addition, in the present embodiment, the load applied to the wafer holding unit 10 when the wafer holding unit 10 and the stage 20 are in contact with each other through the wafer W and the molten resin layer S is detected by a load detector 60 provided on the upper surface of the vacuum forming chamber 2. Such a load detector may also be provided in the wafer holding table 12 of the wafer holding unit 10 or in the resin placement table 22 of the stage 20.

Claims

1. A method for forming a protective member, comprising forming a protective member formed of a thermoplastic resin on one surface of a wafer, wherein: The method for forming the protective component has the following steps: A resin providing step of disposing a plurality of granular thermoplastic resins on a resin loading surface of a carrier; A wafer holding step of holding the other surface of the wafer by the wafer holding surface of the wafer holding unit; A contacting step of moving the wafer holding unit and the stage in a direction in which they are relatively close to each other using an up-and-down moving mechanism, thereby bringing one surface of the wafer held by the wafer holding unit into contact with the granular thermoplastic resin; a resin state recognition step of heating the granular thermoplastic resin in contact with one surface of the wafer and transmitting ultrasonic vibration between the resin loading surface and the wafer holding surface to recognize whether the thermoplastic resin between one surface of the wafer held by the wafer holding surface and the resin loading surface has been integrated; a pushing step of pushing the thermoplastic resin identified as integrated in the resin state identification step over the entire surface of one surface of the wafer through the wafer; as well as The hardening step is to cool and harden the pushed thermoplastic resin. The protective member forming method forms a protective member that protects the entire surface of one surface of a wafer.

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