JP2020102515A - Forming method of protective member - Google Patents

Abstract

To suppress generation of static electricity when removing wrinkles on a sheet.SOLUTION: A forming method of a protective member includes a sheet placing step of placing a sheet 1 on a stage 20, a sheet wrinkle removing step of spreading the sheet 1 with a roller 33 formed of the same material as the sheet 1, a resin supply step of supplying a predetermined amount of liquid resin to the upper surface of the sheet 1, a coating step of spreading the liquid resin between the wafer arranged on the sheet 1 and the sheet 1 to cover the wafer by pressing the wafer through the liquid resin toward the sheet 1, and a curing step of curing the liquid resin to form a protective member.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for forming a protective member on one surface of a wafer.

When a columnar ingot is sliced with a wire saw to form a disk-shaped wafer, the wafer is warped or undulated during slicing. In order to remove these warps and undulations, conventionally, a technique is known in which a resin is applied to one surface of a wafer, the resin is cured to form a protective member, and then the wafer is ground to be flat. (For example, refer to Patent Document 1). In this type of technology, resin is applied (dripping) onto the sheet placed on the stage, and the wafer is pressed against this resin to uniformly apply the resin to the lower surface (one surface) of the wafer. doing.

JP, 2016-167546, A

By the way, if the sheet placed on the stage has wrinkles, the thickness of the resin on the sheet is different. Therefore, before supplying the resin, a step of rolling the roller on the sheet to remove wrinkles from the sheet is performed. Here, in order to disperse the force applied to the sheet, the roller is formed of an elastic member (for example, rubber), or the pad formed of the elastic member is laminated on the sheet, and the metal roller is rolled over the pad. A configuration that allows the use of such information is used.

However, in the above-mentioned configuration, static electricity is generated on the sheet when the roller or pad formed of the elastic member is separated from the sheet, so if the resin is supplied onto the sheet with static electricity generated, the resin will be evenly shaped in a circle. There was a problem that it could not spread evenly and could not be applied uniformly on the entire surface of the wafer. There is also a method of removing the generated static electricity by a removing means such as an ionizer, but this method is time consuming and not efficient.

The present invention has been made in view of the above, and an object of the present invention is to provide a method for forming a protective member that suppresses the generation of static electricity when removing wrinkles from a sheet.

In order to solve the above-mentioned problems and achieve the object, the present invention is a method of forming a protective member for coating a resin on one surface of a wafer, comprising a sheet mounting step of mounting a sheet on a stage. A sheet wrinkle removing step for spreading the sheet by a roller; a resin supplying step for supplying a predetermined amount of liquid resin to the upper surface of the sheet; and a wafer arranged on the sheet via the liquid resin, By pressing the liquid resin between the wafer and the sheet to spread the liquid resin to cover the wafer, and a curing step of curing the liquid resin, and the roller has at least an outer periphery. The surface is made of the same material as the sheet.

According to this configuration, since at least the outer peripheral surface of the roller used in the sheet wrinkle removing step is made of the same material as the sheet, it is possible to reduce peeling charge when peeling the roller from the sheet, and to remove wrinkles from the sheet. Generation of static electricity can be suppressed.

In this configuration, the roller may include a core member made of an elastic member and a roller covering member that covers the core member, and the roller covering member may be made of the same material as the sheet. According to this structure, the force applied to the sheet can be dispersed by the core material of the roller formed of the elastic member and the force can be evenly applied to the sheet, so that the wrinkle of the sheet can be effectively removed.

Further, the present invention is a method for forming a protective member for coating a resin on one surface of a wafer, comprising a sheet placing step of placing a sheet on a stage, and passing the sheet by a roller through a force dispersion pad. And wrinkle the sheet to remove the wrinkles, a resin supplying step of supplying a predetermined amount of the liquid resin to the upper surface of the sheet, and a wafer arranged on the sheet via the liquid resin is pressed toward the sheet. Accordingly, a coating step of spreading the liquid resin between the wafer and the sheet to coat the wafer, and a curing step of curing the liquid resin are provided, and at least the lower surface of the force dispersion pad is It is made of the same material as the seat.

According to this configuration, since at least the lower surface of the force distribution pad used in the sheet wrinkle removing step is made of the same material as the sheet, it is possible to reduce the peeling charge when the force distribution pad is peeled from the sheet. It is possible to suppress the generation of static electricity when removing wrinkles.

In this configuration, the force distribution pad includes a pad body composed of an elastic member and a force distribution pad covering member fixed to a lower portion of the pad body, and the force distribution pad covering member is the sheet. The same material may be used. According to this configuration, by providing the pad main body composed of the elastic member on the surface that does not contact the seat, the force distribution pad becomes strong, and the pad main body disperses the pressure of the roller to apply the force evenly to the seat. Since wrinkles can be added, it is possible to effectively remove wrinkles from the sheet.

According to the present invention, it is possible to suppress the generation of static electricity when removing wrinkles from a sheet.

FIG. 1 is a flowchart showing a procedure of a method for forming a protective member according to this embodiment. FIG. 2 is a schematic diagram illustrating the sheet placing step. FIG. 3 is a schematic diagram illustrating the sheet placing step. FIG. 4 is a schematic diagram illustrating a sheet wrinkle removing step. FIG. 5 is a schematic diagram illustrating a resin supply step. FIG. 6 is a schematic diagram showing the resin supplied on the sheet. FIG. 7 is a schematic diagram illustrating the covering step. FIG. 8 is a schematic diagram illustrating the curing step. FIG. 9 is a schematic diagram illustrating a sheet wrinkle removing step according to another embodiment.

Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the embodiments below. Further, the constituent elements described below include those that can be easily conceived by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be appropriately combined. In addition, various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

FIG. 1 is a flowchart showing a procedure of a method for forming a protective member according to this embodiment. The wafer to which the method for forming a protective member according to the present embodiment is applied is one before a device pattern is formed, and for example, a circle of silicon (Si), gallium arsenide (GaAs), silicon carbide (SiC), or the like. It is an as-slice wafer obtained by slicing (cutting) a columnar ingot into a disc shape with a wire saw. On the lower surface (one surface) of the wafer, waviness or warpage occurs when cutting with a wire saw. In order to remove these waviness and warpage, a resin is applied to the lower surface of the wafer to form a protective member, and then both surfaces of the wafer are sequentially ground to be flattened. As shown in FIG. 1, the method for forming a protective member according to the present embodiment includes a sheet placing step ST1, a sheet wrinkle removing step ST2, a resin supplying step ST3, a covering step ST4, and a curing step ST5. Consists of Each step will be described below.

[Sheet loading step ST1]
2 and 3 are schematic diagrams for explaining the sheet placing step. In the sheet mounting step ST1, as shown in FIGS. 2 and 3, the sheet 1 to which the liquid resin is supplied (dropped) is mounted on the stage 20 by using the transport device 10. The sheet 1 prevents the liquid resin from being dripped directly on the stage 20, protects the upper surface of the stage 20 from being scratched, and saves the time and effort of cleaning. The sheet 1 also facilitates handling (handling) of the wafer coated with the liquid resin. The sheet 1 has a certain degree of flexibility and is formed to be equal to or slightly smaller than the stage 20. The shape of the sheet 1 is rectangular (quadrangular) like the stage 20, but the shape is not limited to this and may be circular or the like. The material of the sheet 1 is polyolefin.

The transport device 10 includes a transport arm 11, a suction pad 12 provided on the lower surface of the transport arm 11 for suctioning the sheet 1, an elevating unit 13 for elevating the transport arm 11 with respect to the stage 20, and an elevating unit 13. And a horizontal movement mechanism (not shown) that moves in the horizontal direction. The horizontal movement mechanism moves the transfer arm 11 supported by the lifting unit 13 between the transfer position on the stage 20 and the retracted position separated from the stage 20. A suction source (not shown) is connected to the suction pad 12 to suck or release the sheet 1. The elevating unit 13 supports one end side of the transfer arm 11 and moves the transfer arm 11 in the vertical direction.

The stage 20 includes a stage body 21, a glass table 22 provided on the stage body 21, and a plurality of UV (ultraviolet) lamps 23 arranged in the stage body 21. The stage main body 21 is formed in a rectangular shape in a plan view, and has, for example, a circular glass table 22 in the center. The glass table 22 has a flat upper surface and serves as a mounting surface for the sheet 1. Further, the glass table 22 does not have to be glass as long as it is a material that transmits ultraviolet rays. The stage 20 may be configured to apply suction force of a suction source (not shown) to the mounting surface to suck and hold the sheet 1.

As shown in FIG. 2, the sheet 1 is adsorbed by the adsorption pad 12 of the conveyance device 10, held by the conveyance arm 11, and conveyed above the stage 20. Next, the transport device 10 lowers the transport arm 11 by the operation of the elevating unit 13, and places the sheet 1 on the glass table 22 of the stage 20 as shown in FIG. When the sheet 1 is placed on the glass table 22 of the stage 20, the carrying device 10 retracts from the stage 20. In this case, the sheet 1 placed on the glass table 22 may be slightly wrinkled 1A. When the resin is supplied onto the sheet 1 in the state where the wrinkles 1A are close to each other, the thickness of the resin on the sheet 1 varies, so that the wrinkles of the sheet 1 are removed.

[Sheet wrinkle removal step ST2]
FIG. 4 is a schematic diagram illustrating a sheet wrinkle removing step. The sheet wrinkle removing step ST2 is executed by using the roller unit 30 that rolls on the sheet 1 placed on the glass table 22, as shown in FIG. The roller unit 30 includes a unit main body 31, an arm portion 32 that is horizontally movable by a moving mechanism provided in the unit main body 31, a roller 33 rotatably attached to the arm portion 32, and a unit main body 31. An elevating unit 34 that elevates and lowers with respect to the stage 20 and a horizontal moving mechanism (not shown) that horizontally moves the elevating unit 34 are provided. The horizontal movement mechanism moves the unit main body 31 supported by the elevating unit 34 between the rolling position on the stage 20 and the retracted position separated from the stage 20.

The roller 33 includes a rotating shaft 35 rotatably supported by the arm portion 32, a cylindrical roller portion (core material) 36 fixed to the rotating shaft 35, and a roller covering the outer peripheral surface of the roller portion 36. And a covering member 37. The roller portion 36 rotates integrally with the rotating shaft 35 and is made of an elastic material such as a rubber material. The length of the roller portion 36 in the longitudinal direction (axial direction) is preferably formed larger than the diameter of the sheet 1. The roller covering member 37 is adhered to the outer peripheral surface of the roller portion 36 and follows the elastic deformation of the roller portion 36. The roller covering member 37 is made of polyolefin which is the same material as the sheet 1. Since this polyolefin can be bonded (welded) to the outer peripheral surface of the roller portion 36 by heating, the roller covering member 37 can be easily provided without using an adhesive.

As shown in FIG. 4, the elevating unit 34 lowers the unit body 31 to the position where the roller 33 contacts the sheet 1 on the glass table 22. Then, by driving a moving mechanism (not shown) in the unit main body 31, the roller 33 is moved via the arm portion 32 from the broken line position to the solid line position. When the roller 33 moves, the roller 33 rolls on the sheet 1. Therefore, the rolling causes the sheet 1 to come into close contact with the glass table 22, and the wrinkles 1A (FIG. 3) of the sheet 1 can be removed (disappeared). Further, in the present embodiment, since the roller portion 36 of the roller 33 is formed of an elastic member, it is possible to disperse the force applied to the sheet 1 and apply the force evenly to the sheet 1, so that the wrinkle removal of the sheet 1 is effective. Can be done.

When the wrinkle removal is completed, the elevating unit 34 raises the unit main body 31 to separate the roller 33 from the sheet 1. In this case, since the roller covering member 37, which is the outer peripheral surface of the roller 33, is formed of the same material as the sheet 1, it is possible to reduce peeling charge when the sheet 1 and the roller 33 are peeled off, and The static electricity generated in 1 can be suppressed.

[Resin supply step ST3]
FIG. 5 is a schematic diagram illustrating the resin supply step, and FIG. 6 is a schematic diagram illustrating the resin supplied on the sheet. The resin supply step ST3 is executed using the resin supply unit 40 shown in FIG. The resin supply unit 40 includes a supply nozzle 41 arranged on the stage 20 (sheet 1) and a pump (not shown) for feeding the liquid resin 42 to the supply nozzle 41, and a predetermined amount of the liquid resin from the supply nozzle 41. 42 is supplied (dropped) to the center of the upper surface 1B of the sheet 1. The liquid resin 42 serves as a protective member that protects one surface of the wafer, and is, for example, an ultraviolet curable resin.

As described above, in the present embodiment, the roller covering member 37 of the roller 33 and the sheet 1 are formed of the same material to suppress static electricity generated in the sheet 1. When the liquid resin is dropped on the sheet 1 while static electricity is being generated, the liquid resin does not spread radially evenly due to the influence of static electricity and does not have a circular shape. On the other hand, in the present embodiment, since the static electricity generated on the sheet 1 is suppressed, the liquid resin dropped on the sheet 1 spreads radially on the sheet 1 as shown in FIG. It becomes a shape. When a predetermined amount of the liquid resin 42 is accumulated on the sheet 1, the supply (dripping) of the liquid resin 42 from the supply nozzle 41 to the sheet 1 is stopped. The supply amount of the liquid resin 42 is determined by the thickness of the portion where the liquid resin is subsequently cured and becomes a protective member and the area of the wafer.

[Coating step ST4]
FIG. 7 is a schematic diagram illustrating the covering step. In the present embodiment, the coating step ST4 is executed by using the wafer transfer unit 50 that holds the above-described wafer (as slice wafer) 2 and transfers it onto the stage 20. The wafer transfer unit 50 includes a unit body 51, a holding portion 52 provided on the lower surface of the unit body 51 for holding the wafer 2, an elevating unit 53 for elevating the unit body 51 with respect to the stage 20, and an elevating unit 53. And a horizontal movement mechanism (not shown) for moving the horizontal direction. The horizontal movement mechanism moves the unit main body 51 supported by the lifting unit 53 between the transport position on the stage 20 and the retracted position separated from the stage 20. The holding portion 52 is made of, for example, porous ceramic or the like, and sucks and holds the wafer 2 on the lower surface (holding surface) of the holding portion 52 by negative pressure of a vacuum suction source (not shown).

After the horizontal movement mechanism is operated to match the position of the center of the stage 20 in the planar direction with the position of the center of the wafer 2 held by the holding portion 52 in the planar direction, the lifting/lowering unit 53 moves the unit main body 51 to the stage. It is lowered toward 20. When the unit main body 51 descends, the holding portion 52 that holds the wafer 2 and the sheet 1 on the stage 20 approach each other and press the liquid resin 42, so that the liquid resin 42 between the wafer 2 and the sheet 1 becomes Expand in the radial direction of the wafer 2. Therefore, the liquid resin 42 is spread over the entire lower surface 2A of the wafer 2 and covers the entire lower surface 2A of the wafer 2.

In the present embodiment, the wafer transport unit 50 that transports the wafer 2 lowers the wafer 2 as it is to press and spread the liquid resin 42, but after transporting the wafer 2 onto the liquid resin 42. Alternatively, the wafer transport unit 50 may be retracted and a pressing unit (not shown) that presses the wafer 2 toward the sheet 1 may spread the liquid resin 42. That is, as long as the wafer 2 located on the sheet 1 is pressed toward the sheet 1 via the liquid resin 42, any means may be used for pressing the wafer 2.

[Curing step ST5]
FIG. 8 is a schematic diagram illustrating the curing step. After executing the covering step ST4, as shown in FIG. 8, a plurality of UV (ultraviolet) lamps 23 arranged in the stage main body 21 are turned on, and the liquid resin 42 is irradiated with ultraviolet light 23A. The liquid resin 42 is hardened by the stimulation of the ultraviolet light 23A, so that a protective member for protecting the entire lower surface 2A of the wafer 2 is formed. Next, the holding portion 52 releases the suction holding of the wafer 2, and the lifting/lowering unit 53 raises the unit main body 51 to separate the holding portion 52 from the wafer 2.

After that, grinding is performed from the upper surface side of the wafer 2 located on the side opposite to the side on which the protective member is provided, for example, by a grinding wheel, and then the protective member is peeled off and then the ground upper surface side is held to hold the wafer 2 The lower surface 2A is ground. As a result, the waviness and warpage of the wafer 2 can be removed to form a flat wafer 2 or a flat wafer that is not affected by bump irregularities, for example.

As described above, the method of forming the protective member according to the present embodiment includes the sheet mounting step ST1 for mounting the sheet 1 on the glass table 22 of the stage 20 and the pressing with the roller 33 formed of the same material as the sheet 1. A sheet wrinkle removing step ST2 for expanding, a resin supplying step ST3 for supplying a predetermined amount of the liquid resin 42 to the upper surface 1B of the sheet 1, and a wafer 2 arranged on the sheet 1 via the liquid resin 42 is directed toward the sheet 1. A pressing step ST4 for spreading the liquid resin 42 between the wafer 2 and the sheet 1 to cover the wafer 2 by pressing and pressing, and a hardening step ST5 for hardening the liquid resin 42 to form a protective member. Since at least the outer peripheral surface of the roller 33 used in the sheet wrinkle removing step ST2 is made of the same material as the sheet 1, it is possible to reduce peeling charge when the roller 33 is peeled from the sheet 1, and remove the wrinkle 1A of the sheet 1. It is possible to suppress the generation of static electricity.

Further, according to the present embodiment, since the roller 33 is configured such that the outer peripheral surface of the roller portion 36 formed of the elastic member is covered with the roller covering member 37 of the same material as the sheet 1, the roller formed of the elastic member. Since the force applied to the sheet 1 can be dispersed and the force can be evenly applied to the sheet 1 by the portion 36, the wrinkles of the sheet 1 can be effectively removed.

Next, another embodiment of the sheet wrinkle removing step ST2 will be described. FIG. 9 is a schematic diagram illustrating a sheet wrinkle removing step according to another embodiment. In this other embodiment, steps other than the sheet wrinkle removing step ST2 are the same as those in the above-described embodiment, and thus the description thereof will be omitted.

The sheet wrinkle removing step ST2 of another embodiment is executed by using the roller unit 60, as shown in FIG. The roller unit 60 includes a unit body 61, an arm portion 62 that is horizontally movable by a moving mechanism provided in the unit body 61, a roller 63 rotatably attached to the arm portion 62, and a unit body 61. An elevating unit 64 that elevates and lowers with respect to the stage 20 and a horizontal movement mechanism (not shown) that horizontally moves the elevating unit 64 are provided. The roller unit 60 also includes a force distribution pad 66 provided below the unit body 31, and a pad frame 65 that surrounds and supports the force distribution pad 66. The pad frame 65 is supported by the lifting unit 64 so as to be lifted and lowered.

The roller 63 is formed of a rigid material such as metal into a cylindrical shape, and is rotatably supported by the arm portion 32. The force distribution pad 66 is disposed on the seat 1, and is fixed to a pad body 67 formed of an elastic material such as a rubber material and a lower surface 67A of the pad body 67, and the lower surface 67A is fixed. And a force-dispersion pad covering member 68 for covering. The force distribution pad covering member 68 is adhered to the lower surface 67A of the pad body 67 and follows the elastic deformation of the pad body 67. Also in this embodiment, the force distribution pad covering member 68 is made of the same material as the sheet 1 such as polyolefin. Since this polyolefin can be bonded (welded) to the lower surface 67A of the pad body 67 by heating, the force-dispersion pad covering member 68 can be easily provided without using an adhesive.

As shown in FIG. 9, the elevating unit 64 lowers the pad frame 65 to a position where the force distribution pad 66 contacts the sheet 1 on the glass table 22. Subsequently, the elevating unit 64 makes the unit body 61 effective until the roller 63 contacts the force distribution pad 66. The pad frame 65 and the unit main body 61 may be moved up and down independently, or may be moved up and down by interlocking the pad frame 65 and the unit main body 61 with the roller 63 contacting the force distribution pad 66. Good.

Next, by driving a moving mechanism (not shown) in the unit main body 61, the roller 63 is moved via the arm portion 62 from the position indicated by the broken line to the position indicated by the solid line. When the roller 63 moves, the roller 63 rolls on the force-dispersing pad 66, so that the rolling causes the sheet 1 to be brought into close contact with the glass table 22 via the force-dispersing pad 66, and the wrinkles 1A of the sheet 1 (Fig. 3) can be taken (disappeared). Further, in the present embodiment, since the pad body 67 of the force distribution pad 66 is formed of an elastic member, the force distribution pad 66 can disperse the force applied to the sheet 1 and apply the force evenly to the sheet 1. The wrinkles on the sheet 1 can be effectively removed.

When the wrinkle removal is completed, the elevating unit 64 raises the unit main body 61 and the pad frame 65 to separate the force distribution pad 66 and the seat 1. In this case, since the force-dispersion pad covering member 68 of the force-dispersion pad 66 is made of the same material as that of the sheet 1, the peeling charge at the time of peeling the sheet 1 and the force-dispersion pad 66 is reduced. Therefore, static electricity generated in the sheet 1 can be suppressed.

The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the gist of the present invention. The method for forming the protective member of the above embodiment is not only to form a protective member by applying a resin to one surface of the wafer in order to remove undulations and warpage that occur in the cut wafer, but also, for example, When grinding a wafer with bumps and other irregularities on the front surface (one surface), a resin may be applied to the front surface to form a protective member, and then the back surface (other surface) of the wafer may be ground. it can.

1 sheet 1B upper surface 2 wafer 10 carrier device 12 suction pad 13 suction unit 13 lifting unit 20 stage 21 stage body 22 glass table 23 UV lamp 23A ultraviolet light 33 roller 34 lifting unit 36 roller unit (core material)
37 Roller Covering Member 41 Supply Nozzle 42 Liquid Resin 52 Holding Section 53 Elevating Unit 63 Roller 64 Elevating Unit 66 Force Dispersing Pad 67 Pad Main Body 67A Lower Surface 68 Force Dispersing Pad Covering Member

Claims (4)

A method of forming a protective member for coating a resin on one surface of a wafer, comprising:
A sheet placing step of placing a sheet on the stage,
A sheet wrinkle removing step of spreading the sheet with a roller,
A resin supplying step of supplying a predetermined amount of liquid resin to the upper surface of the sheet,
A wafer disposed on the sheet through the liquid resin, by pressing toward the sheet, a coating step of spreading the liquid resin between the wafer and the sheet to coat the wafer,
And a curing step of curing the liquid resin,
A method of forming a protective member, wherein at least the outer peripheral surface of the roller is made of the same material as the sheet. The roller is a core member made of an elastic member,
A roller coating member for coating the core material,
The method for forming a protective member according to claim 1, wherein the roller covering member is made of the same material as the sheet. A method of forming a protective member for coating a resin on one surface of a wafer, comprising:
A sheet placing step of placing a sheet on the stage,
A sheet wrinkle removing step of spreading the sheet with a roller through a force distribution pad,
A resin supplying step of supplying a predetermined amount of liquid resin to the upper surface of the sheet,
A wafer disposed on the sheet through the liquid resin, by pressing toward the sheet, a coating step of spreading the liquid resin between the wafer and the sheet to coat the wafer,
And a curing step of curing the liquid resin,
A method of forming a protective member, wherein at least the lower surface of the force distribution pad is made of the same material as the sheet. The force distribution pad is a pad body composed of an elastic member,
A force distribution pad covering member fixed to a lower portion of the pad body,
The method for forming a protective member according to claim 3, wherein the force distribution pad covering member is made of the same material as the sheet.

Images