JP7214466B2 - Method for forming protective member - Google Patents

Description

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

When slicing a cylindrical ingot 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, a conventional technique is known in which a resin is applied to one surface of the wafer, cured to form a protective member, and then the wafer is ground to form a flat surface. (See Patent Document 1, for example). In this type of technology, a resin is supplied (dripped) onto a sheet placed on a stage, and the wafer is pressed against the resin to uniformly apply the resin to the lower surface (one surface) of the wafer. are doing.

JP 2016-167546 A

By the way, if the sheet placed on the stage is wrinkled, the thickness of the resin on the sheet will be different. Therefore, before supplying the resin, a step of rolling a 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 made of an elastic material (e.g., rubber), or a pad made of an elastic material is laminated on the sheet, and a metal roller is rolled over the pad. A configuration is used in which the

However, in the above-described configuration, static electricity is generated on the sheet when the roller or pad made of an elastic member separates from the sheet. There was a problem that the coating could not be spread evenly over the entire surface of the wafer. There is also a method of removing the generated static electricity with a removing means such as an ionizer, but this method takes time and is not efficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of forming a protective member that suppresses the generation of static electricity when removing wrinkles from a sheet.

In order to solve the above-described problems and achieve the object, the present invention provides a method of forming a protective member that coats one surface of a wafer with a resin, comprising: a sheet placing step of placing a sheet on a stage; a sheet wrinkle removal step of spreading the sheet with a roller; a resin supply step of supplying a predetermined amount of liquid resin to the upper surface of the sheet; a covering step of spreading the liquid resin between the wafer and the sheet to cover the wafer; and a curing step of curing the liquid resin. 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 the separation electrification when the roller is peeled from the sheet, and the sheet wrinkle removing step can be performed. Generation of static electricity can be suppressed.

In this configuration, the roller includes a core made of an elastic member and a roller covering member covering the core, and the roller covering member may be made of the same material as the sheet. According to this configuration, 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 applied evenly to the sheet, so wrinkles can be effectively removed from the sheet.

The present invention also provides a method of forming a protective member that coats one surface of a wafer with a resin, comprising: a step of placing a sheet on a stage; a step of removing wrinkles from the sheet to spread it out by pressing it; a step of supplying a predetermined amount of liquid resin to the upper surface of the sheet; and a step of supplying a predetermined amount of liquid resin to the upper surface of the sheet; Thus, the force dispersion pad comprises a coating step of spreading the liquid resin between the wafer and the sheet to cover the wafer, and a curing step of curing the liquid resin, wherein the force distribution pad is composed of the pad main body and the and a force dispersion pad covering member fixed to the lower part of the pad body without an adhesive, and the force dispersion pad covering member is made of the same material as the sheet.

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

In this configuration, the pad body may be made of an elastic member . According to this configuration, by providing the pad body composed of the elastic member on the surface that does not come into contact with the sheet, the force dispersion pad becomes strong, and the pad body distributes the pressure of the rollers evenly on the sheet. Since force can be applied, wrinkles can be effectively removed from the sheet.
Further, in the method of forming the protective member, the force distribution pad covering member may be adhered to the lower surface of the pad body by heating.
Also, in the method of forming the protective member, the force distribution pad covering member may be polyolefin.

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

FIG. 1 is a flow chart showing the steps of a method for forming a protective member according to this embodiment. FIG. 2 is a schematic diagram for explaining the sheet placing step. FIG. 3 is a schematic diagram for explaining the sheet placing step. FIG. 4 is a schematic diagram for explaining the step of removing wrinkles from the sheet. FIG. 5 is a schematic diagram for explaining the resin supply step. FIG. 6 is a schematic diagram showing resin supplied onto a sheet. FIG. 7 is a schematic diagram explaining the covering step. FIG. 8 is a schematic diagram explaining the curing step. FIG. 9 is a schematic diagram illustrating a sheet wrinkle removing step according to another embodiment.

A form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions, or changes in configuration can be made without departing from the gist of the present invention.

FIG. 1 is a flow chart showing the steps of a method for forming a protective member according to this embodiment. A wafer to which the method for forming a protective member according to the present embodiment is applied is a wafer before a device pattern is formed. This is an as-sliced wafer obtained by slicing (cutting) a columnar ingot into discs with a wire saw. The lower surface (one surface) of the wafer is undulated and warped during cutting with a wire saw. In order to remove these undulations and warps, a resin is applied to the lower surface of the wafer to form a protective member, and then both surfaces of the wafer are ground in order to be flattened. As shown in FIG. 1, the method of forming a protective member according to this embodiment includes a sheet placement step ST1, a sheet wrinkle removal step ST2, a resin supply step ST3, a coating step ST4, and a curing step ST5. It consists of Each step will be described below.

[Sheet Placing Step ST1]
2 and 3 are schematic diagrams for explaining the sheet placing step. In the sheet placing step ST1, as shown in FIGS. 2 and 3, the sheet 1 to which the liquid resin is to be supplied (dropped) is placed on the stage 20 using the conveying device 10. FIG. The sheet 1 prevents the liquid resin from dropping directly onto the stage 20, protects the upper surface of the stage 20 from being scratched, and saves the trouble of cleaning. The sheet 1 also facilitates handling of the wafer coated with the liquid resin. The sheet 1 has flexibility to some extent and is formed to be equal to or slightly smaller than the stage 20 . The shape of the sheet 1 is rectangular (square) like the stage 20, but the shape is not limited to this and may be circular. In addition, polyolefin is used as the material of the sheet 1 .

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

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 inside the stage body 21 . The stage main body 21 is formed in a rectangular shape in plan view, and a circular glass table 22, for example, is provided in the central portion. The glass table 22 has a flat upper surface, which serves as a mounting surface for the sheet 1 . Further, the glass table 22 does not have to be made of glass as long as it is made of a material that transmits ultraviolet rays. The stage 20 may be configured to suck and hold the sheet 1 by applying a suction force of a suction source (not shown) to the placement surface.

As shown in FIG. 2, the sheet 1 is sucked by the suction pad 12 of the conveying device 10, held by the conveying arm 11, and conveyed above the stage 20. As shown in FIG. Next, the conveying device 10 lowers the conveying arm 11 by the operation of the lifting 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 conveying device 10 is withdrawn from the stage 20 . In this case, the sheet 1 placed on the glass table 22 may be slightly wrinkled 1A. If the resin is supplied onto the sheet 1 while the wrinkles 1A are present, the thickness of the resin on the sheet 1 varies.

[Sheet Wrinkle Removal Step ST2]
FIG. 4 is a schematic diagram for explaining the step of removing wrinkles from the sheet. As shown in FIG. 4, the sheet wrinkle removing step ST2 is performed using a 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 body 31, an arm portion 32 horizontally movable by a moving mechanism provided in the unit body 31, a roller 33 rotatably attached to the arm portion 32, and the unit body 31. A lifting unit 34 that moves up and down with respect to the stage 20 and a horizontal movement mechanism (not shown) that moves the lifting unit 34 in the horizontal direction are provided. The horizontal movement mechanism moves the unit body 31 supported by the lifting unit 34 between a rolling position on the stage 20 and a retracted position away 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 rubber. It is preferable that the length of the roller portion 36 in the longitudinal direction (axial direction) be 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 adhered (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.

The lifting unit 34 lowers the unit body 31 to a position where the rollers 33 contact the sheet 1 on the glass table 22, as shown in FIG. By driving a moving mechanism (not shown) in the unit main body 31 , the roller 33 is moved between the broken line position and the solid line position via the arm portion 32 . Since the roller 33 rolls on the sheet 1 during movement, the sheet 1 is brought into close contact with the glass table 22 by this rolling, and the wrinkles 1A (FIG. 3) of the sheet 1 are removed (disappeared). Further, in the present embodiment, since the roller portion 36 of the roller 33 is formed of an elastic member, the force applied to the sheet 1 can be dispersed and the force applied to the sheet 1 can be applied evenly. can be done.

When the wrinkle removal is completed, the lifting unit 34 lifts the unit body 31 to separate the roller 33 and the sheet 1 from each other. In this case, since the roller covering member 37, which is the outer peripheral surface of the roller 33, is made of the same material as the sheet 1, it is possible to reduce the peeling electrification when the sheet 1 and the roller 33 are peeled off. Static electricity generated in 1 can be suppressed.

[Resin supply step ST3]
FIG. 5 is a schematic diagram explaining the resin supplying step, and FIG. 6 is a schematic diagram showing the resin supplied onto 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) that feeds the liquid resin 42 to the supply nozzle 41. A predetermined amount of the liquid resin is supplied from the supply nozzle 41. 42 is supplied (dripped) 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, static electricity generated on the sheet 1 is suppressed by forming the roller covering member 37 of the roller 33 and the sheet 1 from the same material. When the liquid resin is dropped while static electricity is generated on the sheet 1, the liquid resin does not radially and uniformly spread due to the static electricity and does not form 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 onto the sheet 1 spreads radially on the sheet 1 and forms a circle as shown in FIG. 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 from the thickness of the portion that will later become a protective member after the liquid resin hardens and the area of the wafer.

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

After operating the horizontal movement mechanism to align the center position of the stage 20 in the plane direction with the center position of the wafer 2 held by the holding part 52 , the lifting unit 53 moves the unit body 51 to the stage. 20 is lowered. When the unit main body 51 descends, the holding portion 52 holding 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 is It expands in the radial direction of the wafer 2 . Therefore, the liquid resin 42 is spread over the entire bottom surface 2A of the wafer 2 and covers the entire bottom surface 2A of the wafer 2 .

In the present embodiment, the wafer transport unit 50 that transports the wafer 2 directly lowers the wafer 2 to press and spread the liquid resin 42 . Alternatively, the liquid resin 42 may be spread by a pressing unit (not shown) that presses the wafer 2 toward the sheet 1 by withdrawing the wafer transport unit 50 . That is, any means for pressing the wafer 2 may be used as long as the wafer 2 positioned on the sheet 1 is pressed toward the sheet 1 through the liquid resin 42 .

[Curing step ST5]
FIG. 8 is a schematic diagram explaining the curing step. After performing 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 to irradiate the liquid resin 42 with ultraviolet light 23A. A protective member that protects the entire lower surface 2A of the wafer 2 is formed by hardening the liquid resin 42 under the stimulation of the ultraviolet light 23A. Next, the holding part 52 releases the suction holding of the wafer 2 , lifts the unit main body 51 by the elevating unit 53 , and separates the holding part 52 from the wafer 2 .

After that, the upper surface of the wafer 2 located on the side opposite to the side on which the protective member is provided is ground by, for example, a grinding wheel. The lower surface 2A of is ground. As a result, it is possible to form a flat wafer 2 by removing undulations and warps of the wafer 2, or a flat wafer that is not affected by unevenness of bumps, for example.

As described above, the method of forming the protective member according to the present embodiment includes the sheet placing step ST1 for placing the sheet 1 on the glass table 22 of the stage 20, and the roller 33 made of the same material as the sheet 1 to push the sheet. A sheet wrinkle removal step ST2 for widening, a resin supply step ST3 for supplying a predetermined amount of liquid resin 42 to the upper surface 1B of the sheet 1, and a wafer 2 placed on the sheet 1 with the liquid resin 42 interposed therebetween, facing the sheet 1. a coating step ST4 in which the liquid resin 42 is spread between the wafer 2 and the sheet 1 to cover the wafer 2 by pressing with a force, and a curing step ST5 in which the liquid resin 42 is cured 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, the peeling electrification when the roller 33 is peeled from the sheet 1 can be reduced, and the wrinkle 1A of the sheet 1 can be removed. It is possible to suppress the generation of static electricity.

Further, according to the present embodiment, the roller 33 is configured such that the outer peripheral surface of the roller portion 36 made of an elastic member is covered with the roller covering member 37 made of the same material as that of the sheet 1. Therefore, the roller made of the elastic member Since the force applied to the sheet 1 can be dispersed by the portion 36 and the force applied to the sheet 1 can be evenly applied, 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, the steps other than the sheet wrinkle removal step ST2 are the same as those in the above-described embodiment, so description thereof will be omitted.

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

The roller 63 is formed in a cylindrical shape from a rigid material such as metal, and is rotatably supported by the arm portion 32 . The force dispersing pad 66 is arranged on the seat 1, and is fixed to a pad body 67 made of an elastic material such as rubber, and a lower surface 67A of the pad body 67 so that the lower surface 67A and a force dispersing pad covering member 68 covering the . The force dispersion 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 . In this embodiment as well, the force dispersing pad covering member 68 is made of polyolefin, which is the same material as the sheet 1 . Since this polyolefin can be adhered (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.

The lifting 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, as shown in FIG. Subsequently, the lifting unit 64 raises the unit body 61 to a position where the roller 63 contacts the force distribution pad 66 . The pad frame 65 and the unit main body 61 may be raised and lowered independently, or the pad frame 65 and the unit main body 61 may be raised and lowered in conjunction with each other while the roller 63 is in contact with the force dispersion pad 66. good.

Next, by driving a moving mechanism (not shown) in the unit main body 61 , the roller 63 is moved between the broken line position and the solid line position via the arm portion 62 . Since the roller 63 rolls on the force dispersing pad 66 when moving, the sheet 1 is brought into close contact with the glass table 22 via the force dispersing pad 66 due to this rolling, and the wrinkle 1A of the sheet 1 is removed. (Fig. 3) can be removed (disappeared). Further, in the present embodiment, since the pad body 67 of the force dispersion pad 66 is made of an elastic member, the force dispersion pad 66 can distribute the force applied to the seat 1 and evenly apply the force to the seat 1. , wrinkles of the sheet 1 can be effectively removed.

When the wrinkle removal is completed, the lifting unit 64 raises the unit body 61 and the pad frame 65 to separate the force distribution pad 66 and the seat 1 . In this case, since the force dispersing pad covering member 68 of the force dispersing pad 66 is made of the same material as the sheet 1, the separation electrification when the sheet 1 and the force dispersing pad 66 are separated is reduced. , and the static electricity generated on the sheet 1 can be suppressed.

It should be noted that the present invention is not limited to the above embodiments. That is, various modifications can be made without departing from the gist of the present invention. In the method of forming the protective member of the above-described embodiment, in order to remove waviness, warp, etc. occurring in the cut wafer, not only is the protective member formed by applying resin to one surface of the wafer, but also, for example, When grinding a wafer having unevenness such as bumps on its front surface (one surface), it can also be used in a configuration in which the rear surface (another surface) of the wafer is ground after the surface is coated with a resin to form a protective member. can.

1 Sheet 1B Upper Surface 2 Wafer 10 Conveying Device 12 Suction Pad 13 Lifting Unit 20 Stage 21 Stage Body 22 Glass Table 23 UV Lamp 23A Ultraviolet Light 33 Roller 34 Lifting Unit 36 Roller Part (Core Material)
37 Roller covering member 41 Supply nozzle 42 Liquid resin 52 Holding part 53 Lifting unit 63 Roller 64 Lifting unit 66 Pad for force distribution 67 Pad main body 67A Lower surface 68 Pad covering member for force distribution

Claims (6)

A method for forming a protective member that coats one surface of a wafer with a resin, comprising:
a sheet placing step of placing the sheet on the stage;
a sheet wrinkle removing step of spreading out the sheet with a roller;
a resin supply step of supplying a predetermined amount of liquid resin onto the upper surface of the sheet;
a covering step of pressing the wafer placed on the sheet through the liquid resin toward the sheet to spread the liquid resin between the wafer and the sheet to cover the wafer;
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 has a core made of an elastic member;
and a roller covering member covering the core material,
2. The method of forming a protective member according to claim 1, wherein the roller covering member is made of the same material as the sheet. A method for forming a protective member that coats one surface of a wafer with a resin, comprising:
a sheet placing step of placing the sheet on the stage;
a sheet wrinkle removing step of spreading out the sheet with a roller through a force dispersion pad;
a resin supply step of supplying a predetermined amount of liquid resin onto the upper surface of the sheet;
a covering step of pressing the wafer placed on the sheet through the liquid resin toward the sheet to spread the liquid resin between the wafer and the sheet to cover the wafer;
a curing step of curing the liquid resin;
The force distribution pad has a pad body and a force distribution pad covering member fixed to the lower part of the pad body without an adhesive,
A method of forming a protective member, wherein the force distribution pad covering member is made of the same material as the sheet. 4. The method of forming a protective member according to claim 3, wherein the pad body is made of an elastic member. 4. The method of forming a protective member according to claim 3, wherein the force distribution pad covering member is adhered to the lower surface of the pad body by heating. 4. The method of claim 3, wherein the force distribution pad covering member is polyolefin.

Images