PROTECTIVE ELEMENT TRAINING PROCEDURE

Abstract

A protective element forming method for forming a protective element (41) on the entirety of one of the two sides (Wa, Wb) of a wafer (W), the protective element forming method comprising: a resin supplying step for supplying a predetermined amount of a first liquid resin (4) to the center of an upper surface (1a) of a substrate (1) to form an accumulation of the first liquid resin (4), wherein the liquid resin (4) has such a weak surface tension that a recess (5) is formed at a center of the accumulated liquid resin (4); a resin applying step of applying an appropriate amount of a second liquid resin (6) to the center of a lower surface (Wb) of the wafer (W) held on a holding surface (12) of a holding unit (10) opposite to the carrier (1), the appropriate amount being determined so that the second liquid resin (6) can be maintained in the state applied to the lower surface (Wb) of the wafer (W) without falling off; a spreading step of aligning the center of the carrier (1) with the center of the wafer (W) held on the holding surface (12) of the holding unit (10), then moving the carrier (1) or the holding unit (10) toward each other until the second liquid resin (6) comes into contact with the first liquid resin (4) and is then pressed into the first liquid resin (4) to fill the recess (5), and then applying a pressing-down force to the first liquid resin (4) interposed between the carrier (1) and the holding unit (10), thereby spreading the first liquid resin (4) in which the recess (5) is eliminated over the entire lower surface (Wb) of the wafer (W); and a curing step for curing the first liquid resin (4) distributed over the entire lower surface (Wb) of the wafer (W), thereby forming the protective member (41).

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a method for forming a resin protective member on the entirety of one of the two sides of a plate-shaped workpiece. Description of the state of the art

[0002] In a manufacturing process for a semiconductor wafer or the like, when a cylindrical ingot is cut by a wire saw to form a circular wafer, a warp or a waviness may be formed in the wafer. As a technique for removing such warp or waviness, there is a method including the steps of applying a liquid resin such as polyethylene to one side of the wafer where the warp or waviness is formed, then curing this liquid resin, and then sequentially grinding the other side of the wafer and this one side thereof to thereby smooth both sides of the wafer.

[0003] In this technique, the liquid resin is applied to one side of the wafer, for example, by the following method. This method includes the steps of dropping the liquid resin onto a sheet arranged on a carrier, holding the wafer under suction using a suction holding unit arranged above the carrier, pressing one side (bottom surface) of the wafer against the sheet to thereby radially distribute the liquid resin over the entirety of that one side of the wafer from the center to the periphery of the wafer, and finally heating the liquid resin or applying ultraviolet light to the liquid resin to thereby cure the liquid resin (see, for example, Japanese Laid-Open Document JP 2012-143723 A).

[0004] Further state of the art can be found in the following documents: US 2014 / 0 158 291 A1 relates to a method for producing a joined element in which a distribution of an adhesive between two elements can be carried out in a short time. US 2009 / 0 183 819 A1 relates to a manufacturing method for a display device. EP 2 695 923 A2 relates to a method for bonding transparent layers using a curable, transparent adhesive. JP 2002 - 285 132 A relates to a method for joining one element to another element using a plastic. US 2011 / 0 130 065 A1 relates to a method for producing a display. SUMMARY OF THE INVENTION

[0005] Unlike a liquid such as water, the liquid resin accumulated on the track has a weak surface tension, so that a recess (cavity) is slightly formed at the center of the accumulated liquid resin. The size of this recess is proportional to the size of the wafer to be coated with the liquid resin. That is, the amount of liquid resin to be used in the case of applying the liquid resin to a large wafer (for example, with a diameter of 450 mm) is larger than that in the case of applying the liquid resin to a small wafer (for example, with a diameter of 200 mm). Accordingly, the size of the recess formed at the center of the accumulated liquid resin is larger for the large wafer than for the small wafer.

[0006] In particular, if the liquid resin is applied to the large wafer, there is a possibility that when the accumulated liquid resin is pressed down by one side of the wafer, air may enter the recess of the accumulated liquid resin. Accordingly, even after the dispersed liquid resin is cured, air bubbles may be formed in the cured liquid resin. As a result, even if the other side of the wafer is ground in the state where one side of the wafer is protected by the cured liquid resin, a protrusion may be formed on the ground wafer. Therefore, it is difficult to grind the wafer with high accuracy.It is therefore an object of the present invention to provide a protective member forming method which can prevent the entry of air bubbles into a liquid resin to be formed into a protective member for protecting the entire one side of a wafer.

[0007] According to one aspect of the present invention, there is provided a protective member forming method for forming a protective member on the entirety of one of both sides of a wafer, the protective member forming method including: a resin supplying step of supplying a predetermined amount of a first liquid resin to the center of an upper surface of a carrier to form a pool of the first liquid resin, the liquid resin having such a weak surface tension that a recess is formed at a center of the pooled liquid resin;a resin applying step of applying an appropriate amount of a second liquid resin to the center of a lower surface of the wafer held on a holding surface of a holding unit opposite to the carrier, the appropriate amount being determined so that the second liquid resin can be maintained in the state applied to the lower surface of the wafer without falling off;a spreading step of aligning the center of the carrier with the center of the wafer held on the holding surface of the holding unit, then moving the carrier or the holding unit toward each other until the second liquid resin comes into contact with the first liquid resin and is then pressed into the first liquid resin to fill the recess, and then applying a pressing-down force to the first liquid resin interposed between the carrier and the holding unit, thereby spreading the first liquid resin, in which the recess is eliminated, over the entire lower surface of the wafer; and a curing step of curing the first liquid resin spread over the entire lower surface of the wafer, thereby forming the protective member.

[0008] According to another aspect of the present invention, there is provided a protective member forming method for forming a protective member on the entirety of one of both sides of a wafer, the protective member forming method including: a resin supplying step of supplying a predetermined amount of a first liquid resin to the center of an upper surface of a wafer held on a holding surface of a holding unit to form a pool of the first liquid resin, the liquid resin having such a weak surface tension that a recess is formed at a center of the pooled liquid resin;a resin applying step of applying an appropriate amount of a second liquid resin to the center of a lower surface of a substrate facing the holding surface of the holding unit, the appropriate amount being determined so that the second liquid resin can be maintained in the state applied to the lower surface of the substrate without falling off;a spreading step of aligning the center of the wafer held on the holding surface of the holding unit with the center of the carrier, then moving the holding unit or the carrier toward each other until the second liquid resin comes into contact with the first liquid resin and is then pressed into the first liquid resin to fill the recess, and then applying a pressing force to the first liquid resin interposed between the holding unit and the carrier, thereby spreading the first liquid resin, in which the recess is eliminated, over the entire upper surface of the wafer; and a curing step of curing the first liquid resin spread over the entire upper surface of the wafer, thereby forming the protective member.

[0009] According to the protective member forming method of the present invention, in the resin supplying step, the predetermined amount of the first liquid resin is supplied to the center of the upper surface of the carrier or the center of the upper surface of the wafer held on the holding surface of the holding unit. Then, in the resin attaching step, the appropriate amount of the second liquid resin is attached to the center of the lower surface of the wafer held on the holding surface of the holding unit or to the center of the lower surface of the carrier. Then, in the spreading step, a pressing force is applied to the first liquid resin interposed between the carrier and the holding unit, thereby spreading the first liquid resin over the entire lower surface or the entire upper surface of the wafer.Accordingly, even if a recess (cavity) is formed on the first liquid resin supplied in the resin supply step, this recess of the first liquid resin is filled with the second liquid resin forced into the first liquid resin in the dispensing step, thereby eliminating the recess in the dispensed first liquid resin. As a result, in the subsequent curing step, the protective member can be formed on either side of the wafer without air bubbles. Accordingly, during subsequent wafer grinding, both sides of the wafer can be smoothed with high accuracy.

[0010] The above and other objects, features and advantages of the present invention and the mode for carrying them out will become more apparent and the invention itself will be best understood by studying the following description and the appended claims with reference to the accompanying drawings which show some preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A and Fig. 1B are sectional views showing a resin supplying step for supplying a first liquid resin according to a first preferred embodiment of the present invention; Fig. 2 is a sectional view showing a resin applying step for applying a second liquid resin according to the first preferred embodiment; Fig. 3 is a sectional view showing a state in which the second liquid resin in the Fig. 2 shown resin attachment step to the bottom surface of a wafer; Fig. 4 is a sectional view showing a dispensing step for dispensing the first liquid resin after forcing the second liquid resin thereinto according to the first preferred embodiment; Fig. 5 is a sectional view showing a state in which the first liquid resin in the Fig. 4 in the radial direction of the wafer; Fig. 6 is a sectional view showing a curing step for curing the dispersed first liquid resin according to the first preferred embodiment; Fig. 7 is a sectional view showing a resin supplying step and a resin attaching step according to a second preferred embodiment of the present invention; Fig. Fig. 8 is a sectional view showing a distributing step according to the second preferred embodiment; and Fig. 9 is a sectional view showing a curing step according to the second preferred embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a method of forming a protective member for protecting the entirety of one of both sides of a wafer as a workpiece will be described with reference to the accompanying drawings. 1. First Preferred Embodiment of the Protective Member Forming Method (1) Resin Supplying Step

[0012] As in Fig. As shown in Figure 1A, a sheet 2 is placed on the upper surface 1a of a substrate 1, and a suction force generated by a vacuum source (not shown) is applied to the upper surface 1a of the substrate 1, thereby holding the sheet 2 on the upper surface 1a under suction. The material of the sheet 2 is not particularly limited. For example, the sheet 2 may be formed of PET (polyethylene terephthalate).

[0013] Thereafter, a predetermined amount of a liquid resin 4 is dropped from a resin supply nozzle 3 arranged above the carrier 1 onto the center of the upper surface of the web 2 held under suction on the upper surface 1a of the carrier 1. The liquid resin 4 is a material of the protective member for protecting the entirety of one of the two sides of the wafer. For example, ultraviolet-curable resin can be used as the liquid resin 4. When the dropped liquid resin 4 is applied to the upper surface of the web 2 to form a pool of liquid resin 40, as shown in Fig. 1B, the supply of the liquid resin 4 from the resin supply nozzle 3 to the web 2 is stopped. As shown in Fig. As shown in Fig. 1B, a recess (recess) 5 is formed at the central portion of the liquid resin 40 accumulated on the track 2. The amount of the liquid resin 4 to be dropped is determined by the thickness of the protective member to be formed later by curing the liquid resin 40 and the area of ​​the wafer. (2) Resin application step

[0014] As in Fig. As shown in Fig. 2, a wafer W held by a holding unit 10 is arranged so as to face the upper surface 1a of the carrier 1. The wafer W is a circular wafer formed by cutting a cylindrical ingot with a wire saw, and no components have yet been formed on this wafer.

[0015] The holding unit 10 includes a porous member 11 having a holding surface 12 for holding the wafer W under suction. The porous member 11 is selectively connected to a vacuum source (not shown) in such a way that a suction force generated by this vacuum source is releasably applied to the holding surface 12. A lifting means 13 is connected to the holding unit 10 so as to move the holding unit 10 vertically toward or away from the carrier 1. A resin applying means 14 is provided in the vicinity of the holding unit 10 so as to apply a liquid resin 6 to the lower surface Wb of the wafer W. The resin applying means 14 includes a strut-shaped plate 15 for applying the liquid resin 6 thereto, a rotating unit 16 for rotating the plate 15 about a vertical axis, and a lifting unit 17 for vertically moving the plate 15.Accordingly, when the platen 15 is rotated by the rotating unit 16, the platen 15 can be moved between a position where the liquid resin 6 is dropped onto the platen 15 from a nozzle or the like and a position where the liquid resin 6 attached to the platen 15 is attached to the lower surface Wb of the wafer W. The holding surface 12 of the holding unit 10 may be formed with a suction groove communicating with the vacuum source so as to hold the wafer W under suction.

[0016] The holding unit 10 is operated in such a manner that a suction force generated by the vacuum source is applied to the holding surface 12, thereby holding the upper surface Wa of the wafer W on the holding surface 12 under suction so that the lower surface Wb of the wafer W faces the upper surface of the web 2 held on the upper surface 1a of the carrier 1 under suction. Thereafter, an appropriate amount of the liquid resin 6 is applied to the upper surface of the plate 15 at one end thereof. Thereafter, the rotating unit 16 is operated to rotate the plate 15 to the position immediately below the center of the wafer W held by the holding unit 10. The amount of the liquid resin 6 to be applied is a small amount so that the liquid resin 6 can be maintained in the state attached to the lower surface Wb of the wafer W without falling off. The liquid resin 6 is similar to the liquid resin 4.

[0017] While in this preferred embodiment, in the resin application means 14, the plate 15 is rotated by the rotating unit 16 to apply the liquid resin 6 to the center of the wafer W, the plate 15 may be moved linearly to apply the liquid resin 6 to the center of the wafer W. As a further modification, a wafer handling unit for holding the peripheral portion of a wafer may be used, the wafer handling unit having a horizontal rotation axis around which the wafer held by the wafer handling unit is rotated. In this modification, the liquid resin 6 is directly applied to the upper surface of the wafer held by the wafer handling unit. Thereafter, the wafer holding the liquid resin 6 is rotated around the rotation axis by operating the wafer handling unit. Thereafter, the wafer holding the liquid resin 6 is held by the holding unit 10.

[0018] With further reference to Fig. 2, the lifting unit 17 of the resin attachment means 14 is operated to lift the plate 15 until the liquid resin 6 attached to the plate 15 is attached to the lower surface Wb of the wafer W at the center thereof. Fig. 3 shows the state in which the liquid resin 6 is attached to the center of the lower surface Wb of the wafer W and the platen 15 is retracted. The liquid resin 6 is maintained in its attached state on the lower surface Wb of the wafer W without falling off the lower surface Wb. While in this preferred embodiment, the platen 15 is lifted to attach the liquid resin 6 to the lower surface Wb of the wafer W, the holding unit 10 can be lowered by operating the lifting means 13 until the lower surface Wb of the wafer W comes into contact with the liquid resin 6 attached to the platen 15. (3) Distribution step

[0019] In the Fig. 3, the center of the carrier 1 in a horizontal direction is adjusted to coincide with the center of the wafer W in a horizontal direction. Thereafter, as shown in Fig. 4, the lifting means 13 is actuated to lower the holding unit 10 toward the carrier 1 until the liquid resin 6 attached to the lower surface Wb of the wafer W comes into contact with the liquid resin 40 present on the track 2. More specifically, the liquid resin 6 comes into contact with the lower end of the recess 5 formed at the center of the liquid resin 40 accumulated on the track 2 before the lower surface Wb of the wafer W comes into contact with the accumulated liquid resin 40 on the track 2. As the holding unit 10 is further lowered, the liquid resin 6 that has come into contact with the lower end of the recess 5 is forced into the liquid resin 40, thereby filling the recess 5. That is, the liquid resin 6 is integrated with the liquid resin 40, so that the recess 5 is filled. Thereafter, the holding unit 10 is further lowered to exert a downward force on the liquid resin 40.As a result, the liquid resin 40 is distributed in the radial direction of the wafer W so as to be interposed between the wafer W and the web 2, as shown in FIG. Fig. 5. In such a distributed state of the liquid resin 40, no recess is formed on the liquid resin 40, so there is no possibility of air entering the liquid resin 40. In this way, the liquid resin 40 is distributed over the entire lower surface Wb of the wafer W.

[0020] While in this preferred embodiment the holding unit 10 is lowered in the dispensing step, the carrier 1 may be raised instead. In other words, the carrier 1 or the holding unit 10 may be moved toward each other to force down the liquid resin 40. (4) Curing step

[0021] After the distribution step has been carried out, a curing step is carried out by applying ultraviolet light from a plurality of ultraviolet lamps 18 to the liquid resin 40, as shown in Fig. 6, in order to thereby Fig. 5. The plurality of ultraviolet lamps 18 are provided within the carrier 1. Therefore, the liquid resin 40 is cured by the ultraviolet light to thereby form a protective member 41 for protecting the entire lower surface Wb of the wafer W, as shown in Fig. 6. Thereafter, the suction holding of the upper surface Wa of the wafer on the holding surface 12 of the holding unit 10 is released. Thereafter, the lifting means 13 is operated to lift the holding unit 10 so that the holding surface 12 is separated from the upper surface Wa of the wafer W. Thereafter, the upper surface Wa of the wafer W is ground by using a grinding wheel or the like. Thereafter, the protective member 41 is peeled off from the lower surface Wb of the wafer W, and then the lower surface Wb is ground by the grinding wheel in the state where the upper surface Wa is held on a horizontal table.

[0022] In the protective member forming method described above, the resin attachment step is performed after the resin supplying step is performed to attach the liquid resin 6 to the center of the upper surface Wb of the wafer W held under suction on the holding surface 12 of the holding unit 10 in a small amount so that the liquid resin 6 can be maintained in the state attached to the lower surface Wb without falling off. Thereafter, the spreading step is performed to spread the liquid resin 40 over the entire lower surface Wb of the wafer W. That is, in the spreading step, the liquid resin 6 attached to the lower surface Wb of the wafer W is first brought into contact with the lower end of the recess 5 formed on the accumulated liquid resin 40, and then the lower surface Wb of the wafer W in the other region comes into pressure contact with the liquid resin 40 to press down the liquid resin 40.Accordingly, the recess 5 is eliminated by the liquid resin 6 when the liquid resin 40 is pressed down, so that no air bubbles enter the liquid resin 40 when the liquid resin 40 is spread over the entire lower surface Wb of the wafer W.

[0023] Thereafter, the curing step is performed to cure the dispersed liquid resin 40, thereby forming the protective member 41 for protecting the entire lower surface Wb of the wafer W. Accordingly, in the subsequent grinding step, both sides of the wafer W can be smoothed. 2. Second preferred embodiment of the protective element forming step

[0024] The second preferred embodiment of the present invention is similar to the first preferred embodiment except that the carrier 1 for holding the web 2 and the holding unit 10 for holding the wafer W shown in Fig. 1A to 6 are reversed. That is, as shown in Fig. As shown in Fig. 7, in the second preferred embodiment, a holding unit 20 for holding the wafer W is arranged below a carrier 23 for holding a web 2a. In this case, the carrier 23 is vertically movable. (1) Resin feeding step

[0025] As in Fig. As shown in Fig. 7, the holding unit 20 includes a porous member 21 having a holding surface 22. The holding surface 22 is connected to a vacuum source (not shown). The lower surface Wb of the wafer W is held on the holding surface 22 of the holding unit 20 under suction, and a predetermined amount of a liquid resin is dropped onto the center of the upper surface Wa of the wafer W held on the holding surface 22 under suction, thereby forming a pool of liquid resin 40a on the upper surface Wa of the wafer W at its central portion. The pooled liquid resin 40a has a central recess (recess) 5a. The amount of liquid resin to be dropped is determined by the thickness of the protective member to be formed later by curing the liquid resin 40a and the area of ​​the wafer W, similarly to the first preferred embodiment.The holding surface 22 of the holding unit 20 may be formed with a suction groove communicating with the vacuum source so as to hold the wafer W under suction. (2) Resin application step

[0026] As in Fig. As shown in Fig. 7, the wafer W held on the holding surface 22 of the holding unit 20 faces the lower surface (holding surface) 23a of the carrier 23. The holding surface 23a of the carrier 23 is connected to a vacuum source (not shown). A suction force generated by the vacuum source is applied to the holding surface 23a of the carrier 23, thereby holding the web 2a on the holding surface 23a under suction. Accordingly, the lower surface of the web 2a held under suction on the holding surface 23a of the carrier 23 faces the upper surface Wa of the wafer W held under suction on the holding surface 22 of the holding unit 20.

[0027] Thereafter, a resin application means 14a, which is similar to the resin application means 14 in the first preferred embodiment, is operated to apply an appropriate amount of a liquid resin 6a to the lower surface of the web 2a. That is, the resin application means 14a includes a brace-shaped plate 15 for applying the liquid resin 6a thereto, a rotating unit 16 for rotating the plate 15 about a vertical axis, and a lifting unit 17 for vertically moving the plate 15. As shown in Fig. As shown in Fig. 7, the liquid resin 6a is applied to the upper surface of the plate 15 at one end thereof. Thereafter, the rotating unit 16 is actuated to rotate the plate 15 to the position immediately below the center of the web 2a held by the carrier 23. Thereafter, the lifting unit 17 is actuated to lift the plate 15 until the liquid resin 6a applied to the plate 15 is applied to the lower surface of the web 2a at the center thereof. As shown in Fig. As shown in Fig. 8, the liquid resin 6a is maintained in its state of being attached to the lower surface of the sheet 2a without falling off. The amount of the liquid resin 6a to be attached is a small amount, so that the liquid resin 6a can be maintained in the state of being attached to the lower surface of the sheet 2a without falling off. While in this preferred embodiment, the platen 15 is raised to apply the liquid resin 6a to the lower surface of the sheet 2a, the carrier 23 may be lowered instead.

[0028] While in this preferred embodiment, in the resin application means 14a, the plate 15 is rotated by the rotating unit 16 to apply the liquid resin 6a to the center of the web 2a, the rotating unit 16 may be replaced by a linear motion unit for linearly moving the plate 15 from the outside of the web 2a toward the center of the web 2a. That is, the plate 15 can be moved linearly to apply the liquid resin 6a to the center of the web 2a. (3) Distribution step

[0029] After the resin attachment step is performed, the center of the carrier 23 in a horizontal direction is adjusted to coincide with the center of the wafer W in a horizontal direction. Thereafter, as shown in Fig. 8, the carrier 23 is lowered to bring the sheet 2a held by the carrier 23 into pressure contact with the accumulated liquid resin 40 on the wafer W. More specifically, before the lower surface of the sheet 2a comes into contact with the accumulated liquid resin 40a on the wafer W, the liquid resin 6a attached to the lower surface of the sheet 2a comes into contact with the lower end of the recess 5a formed at the center of the accumulated liquid resin 40a on the wafer W. Thereafter, as the carrier 23 is further lowered, the liquid resin 6a that has come into contact with the lower end of the recess 5a is pressed into the liquid resin 40a, thereby filling the recess 5a. That is, the liquid resin 6a is integrated with the liquid resin 40a to thereby fill the recess 5a. Thereafter, the carrier 23 is further lowered to thereby radially distribute the liquid resin 40a on the upper surface Wa of the wafer W.In such a dispersed state of the liquid resin 40a, no air is included in the liquid resin 40a.

[0030] While in this preferred embodiment the carrier 23 is lowered in the dispensing step, the holding unit 20 may be raised instead. In other words, the carrier 23 or the holding unit 20 may be moved toward each other to force down the liquid resin 40a. (4) Curing step

[0031] After the spreading step has been performed, a curing step is performed by applying ultraviolet light from a plurality of ultraviolet lamps 18a to the liquid resin 40a, as shown in Fig. 9, in order to thereby Fig. 8. The plurality of ultraviolet lamps 18a are provided within the carrier 23. Therefore, the liquid resin 40a is cured by the ultraviolet light to thereby form a protective member 41a for protecting the entire upper surface Wa of the wafer W, as shown in Fig. 9. In the spreading step, when the liquid resin 40a is spread over the entire upper surface Wa of the wafer W, no air bubbles enter the liquid resin 40a. Accordingly, in the subsequent grinding step performed after the curing step, both sides of the wafer W can be smoothed.

[0032] The structure of the resin application means 14 or 14a is not limited to that described above. For example, a conduit may be provided within the plate 15 to supply the liquid resin 6 or 6a through this conduit to the front end of the plate 15, from which the liquid resin 6 or 6a can be discharged.

Claims

[1] A protective element forming method for forming a protective element (41) on the entirety of one of the two sides (Wa, Wb) of a wafer (W), the protective element forming method comprising: a resin supplying step for supplying a predetermined amount of a first liquid resin (4) to the center of an upper surface (1a) of a substrate (1) to form an accumulation of the first liquid resin (4), wherein the liquid resin (4) has such a weak surface tension that a recess (5) is formed at a center of the accumulated liquid resin (4); a resin applying step of applying an appropriate amount of a second liquid resin (6) to the center of a lower surface (Wb) of the wafer (W) held on a holding surface (12) of a holding unit (10) opposite to the carrier (1), the appropriate amount being determined so that the second liquid resin (6) can be maintained in the state applied to the lower surface (Wb) of the wafer (W) without falling off; a spreading step of aligning the center of the carrier (1) with the center of the wafer (W) held on the holding surface (12) of the holding unit (10), then moving the carrier (1) or the holding unit (10) toward each other until the second liquid resin (6) comes into contact with the first liquid resin (4) and is then pressed into the first liquid resin (4) to fill the recess (5), and then applying a pressing-down force to the first liquid resin (4) interposed between the carrier (1) and the holding unit (10), thereby spreading the first liquid resin (4) in which the recess (5) is eliminated over the entire lower surface (Wb) of the wafer (W); and a curing step for curing the first liquid resin (4) distributed over the entire lower surface (Wb) of the wafer (W), thereby forming the protective member (41). [2] A protective element forming method for forming a protective element (41) on the entirety of one of the two sides (Wa, Wb) of a wafer (W), the protective element forming method comprising: a resin supplying step for supplying a predetermined amount of a first liquid resin (40a) to the center of an upper surface (Wa) of a wafer (W) held on a holding surface (22) of a holding unit (20) to form an accumulation of the first liquid resin (4), wherein the liquid resin (4) has such a weak surface tension that a recess (5a) is formed at a center of the accumulated liquid resin (4); a resin applying step of applying an appropriate amount of a second liquid resin (6a) to the center of a lower surface of a substrate (23) opposite to the holding surface (22) of the holding unit (20), the appropriate amount being determined so that the second liquid resin (6a) can be maintained in the state applied to the lower surface of the substrate (23) without falling off; a spreading step of aligning the center of the wafer (W) held on the holding surface (22) of the holding unit (20) with the center of the carrier (23), then moving the holding unit (20) or the carrier (23) toward each other until the second liquid resin (6a) comes into contact with the first liquid resin (40a) and is then pressed into the first liquid resin (40a) to fill the recess (5a), and then applying a pressing-down force to the first liquid resin (40a) interposed between the holding unit (20) and the carrier (23), thereby spreading the first liquid resin (40a) in which the recess (5) is eliminated over the entire upper surface (Wa) of the wafer (W); and a curing step for curing the first liquid resin (40a) distributed over the entire upper surface (Wa) of the wafer (W), thereby forming the protective member (41).

Images