JP2021034605A - Dividing method for wafer - Google Patents

Abstract

To prevent adhesion of glue to chips when dividing a wafer into the chips.SOLUTION: A dividing method for a wafer W comprises the steps of: dripping water onto an upper surface of a base 10; holding the wafer W flat on the upper surface of the base 10 by means of surface tension of the water; supporting a ring frame F on a ring frame support 11 so as to surround the wafer W and positioning the ring frame F substantially at the same height as the wafer W; covering an opening of the ring frame F and the wafer W with a film T2; forming a work set by pressing the film T2 against the wafer W under application of heat in a vacuumed chamber 2 to thermally bond them without glue and, in addition, by bonding the film T2 to the ring frame F; extracting the work set from the chamber 2 and peeling a protective tape T1 applied to one surface of the wafer W; and dividing, along streets, the work set from which the protective tape T1 has been peeled.SELECTED DRAWING: Figure 6

Description

The present invention relates to a method for dividing a wafer.

In the cutting process for semiconductor wafers, etc., a dicing tape is attached to the back surface of the wafer in which the device is formed in the area partitioned by the grid-like streets on the front surface, and the wafer is held by the chuck table via the dicing tape. A wafer is cut along a street with a cutting blade to form a chip (see, for example, Patent Document 1).

JP-A-2017-157748 Japanese Unexamined Patent Publication No. 2012-091245

The chip after cutting is peeled off from the dicing tape for die bonding or the like. At this time, there is a problem that the glue of the dicing tape adheres to the chip and the adhesion of the glue causes poor contact in device manufacturing.

Further, the back surface of the wafer is ground to a predetermined thickness of 20 μm to 100 μm before cutting. This grinding causes grinding strain on the wafer, and the ground back side may be curved so as to be dented. In order to cut the wafer, the dicing tape needs a strong adhesive force to correct this curvature. The strong adhesive force of this glue is a factor that causes the glue to adhere to the chip.

Therefore, when the wafer is divided into chips, there is a problem to be solved that glue is not adhered to the chips after the wafer is divided and processed.

In the present invention for solving the above problems, a protective tape is attached to one surface of a wafer having a grid-like street for partitioning a plurality of devices formed on one surface, and the protective tape is attached by a chuck table. A method for dividing a wafer, which is held through a wafer and whose other surface opposite to one surface is ground by a grinding wheel, is divided by a dividing means along the street. A water supply step of dropping water on the upper surface of the base to be held, and the protective tape attached to the wafer are brought into contact with the water dropped on the upper surface of the base, and the upper surface of the base and the protection are brought into contact with each other. A holding step of spreading the water between the tape and flattening the wafer by the surface tension of the water and holding the wafer on the upper surface of the base, and surrounding the wafer held on the base. A frame arranging step in which a ring frame having an inner diameter larger than the outer diameter of the wafer is supported by a ring frame support base and positioned at substantially the same height as the wafer, and the ring frame opening and the base are held from above. A film arranging step of covering the wafer with a polyolefin-based film, a decompression step of accommodating the wafer, the ring frame, and the film in a room and depressurizing the room, and the film in the decompressed room. To heat the film or the wafer, heat-bond the film and the wafer without using glue, and further bond the film and the ring frame to the wafer and the ring frame. An integral forming step of integrating the film and forming a work set, a protective tape peeling step of taking out the work set from the chamber and peeling off the protective tape attached to one surface, and the protective tape. This is a wafer dividing method including a dividing step of holding the work set from which the wafer has been peeled off on a chuck table of a dividing device and dividing the wafer by the dividing means along the street.

In the integral forming step, it is preferable that the film is pressed against the ring frame to heat the film or the ring frame, and the film and the ring frame are thermally adhered to each other.

In the method for dividing a wafer according to the present invention, the film is provided with an annular glue corresponding to the ring frame, and the film is attached to the ring frame via the glue before the decompression step. The frame set forming step of closing the opening of the ring frame with the film to form the frame set and the depressurizing step are performed by accommodating the wafer and the frame set in the chamber and depressurizing the chamber. In the depressurized room, the film is pressed against the wafer to heat the film or the wafer, and the film and the wafer are heat-bonded without using glue, and the wafer, the ring frame and the film are attached to each other. It is preferable to integrate them to form the work set.

In the method for dividing a wafer according to the present invention, the film includes an annular glue corresponding to the ring frame and an annular outer glue corresponding to the outer peripheral region of the other surface of the wafer, up to before the decompression step. In addition, a frame set forming step of attaching the film to the ring frame via the glue and closing the opening of the ring frame with the film to form a frame set, and the depressurizing step are performed on the wafer and the frame set. The film is pressed against the wafer in the depressurized chamber, and the outer peripheral glue is adhered to the outer peripheral region of the other surface of the wafer. A temporary bonding step of integrating the wafer, the ring frame, and the film so that the central region of the other surface of the wafer and the film are not bonded, and after the temporary bonding step, the film or the wafer is heated. It is preferable to include a heat bonding step of heat-bonding the film and the wafer without using glue, and integrating the wafer, the ring frame, and the film to form the work set.

In the method for dividing a wafer according to the present invention, the protective tape attached to the wafer is brought into contact with water dropped on the upper surface of the base in the water supply step, and water is passed between the upper surface of the base and the protective tape. The holding process of flattening the wafer by the surface tension of water and holding it on the upper surface of the base, and supporting the ring frame on the ring frame support base so as to surround the wafer held on the base, which is approximately the same height as the wafer. The film or wafer is pressed against the wafer in a room where the pressure is reduced by the frame placement process, the film placement process in which the opening of the ring frame and the wafer held on the base are covered with a polyolefin-based film, and the decompression process. The film and the wafer are heat-bonded without using glue, the film and the ring frame are bonded, and the wafer, the ring frame and the film are integrated to form a work set, and protection. By providing a dividing step of dividing the wafer from which the protective tape has been peeled off in the tape peeling step by a dividing means along the street, for example, a wafer warped by grinding can be held as a base in a holding step. The warpage is corrected by the surface tension of the water dropped on the wafer, and a film functioning as, for example, a dicing tape can be attached to the wafer and the ring frame so as not to allow air to enter and integrated. Further, since the film attached to the wafer is not attached to the wafer by glue, it is necessary to prevent the adhesive residue of the chip from being generated when the chip is peeled from the film after the wafer is divided. Is possible.

In the integral forming step, the film and the ring frame can be thermally bonded by pressing the film against the ring frame and heating the film or the ring frame.

In the method for dividing a wafer according to the present invention, the film is provided with an annular glue corresponding to the ring frame, and the film is attached to the ring frame via the glue before the decompression step, and the opening of the ring frame is made of a film. By carrying out the frame set forming step of forming the closing frame set, the film can be handled via the ring frame, so that the handling of the film can be facilitated. Further, in the depressurization step, the wafer and the frame set are housed in the room to reduce the pressure in the room, and in the integral forming step, the film is pressed against the wafer in the decompressed room to heat the film or the wafer, and the film and the wafer are glued. The film attached to the wafer is not attached to the wafer by glue by heat-adhering without using the wafer and integrating the wafer, ring frame, and film to form a work set. After the wafer is divided, it is possible to prevent the adhesive residue of the chip from being generated when the chip is peeled from the film.

In the method for dividing a wafer according to the present invention, the film includes an annular glue corresponding to a ring frame and an annular outer glue corresponding to an outer peripheral region of the other surface of the wafer, and the glue is applied before the decompression step. By carrying out the frame set forming step of attaching the film to the ring frame through the ring frame and closing the opening of the ring frame with the film to form the frame set, the film can be handled through the ring frame. It can be handled easily. Further, in the depressurization step, the wafer and the frame set are housed in the room to reduce the pressure in the room, and in the integral forming step, the film is pressed against the wafer in the decompressed room and the outer peripheral glue is adhered to the outer peripheral region of the other surface of the wafer. A temporary bonding step of integrating the wafer, the ring frame, and the film so that the central region of the other surface of the wafer and the film are not bonded, and after the temporary bonding step, the film or the wafer is heated to form the film and the wafer. The film attached to the device chip in which the wafer is divided is provided with a heat bonding process in which the wafer is heat-bonded without using glue, and the wafer, the ring frame, and the film are integrated to form a work set. Since it is not attached to each chip by glue, it is possible to prevent the adhesive residue of the chip from being generated when the chip is peeled from the film.

It is a perspective view which shows an example of a wafer. It is a side view which shows the state which the water is dropped on the upper surface of the base which holds a wafer. It is sectional drawing which shows the state in which the protective tape attached to a wafer is brought into contact with water dropped on the upper surface of a base. Water is spread between the upper surface of the base and the protective tape, the wafer is flattened by the surface tension of the water and held on the upper surface of the base, and the ring frame is supported by the ring frame support and is approximately the same height as the wafer. It is sectional drawing which shows the state positioned in. It is sectional drawing explaining the state which covers the opening of a ring frame and the wafer held by a base with a film from above. It is sectional drawing explaining the case where a wafer, a ring frame, and a film are housed in a room, and the room is depressurized. In a depressurized room, the film is pressed against the wafer to heat the film or wafer and heat-bond it without using glue, and then the film is pressed against the ring frame to heat and heat-bond the film or ring frame to form the wafer and ring frame. It is sectional drawing explaining the case which integrates with a film and forms a work set. It is sectional drawing of the work set taken out from the room. It is sectional drawing explaining the state in which the protective tape attached to one surface of the wafer of a work set is peeled off. It is sectional drawing explaining the state in which the work set from which the protective tape was peeled off is held by the chuck table of the dividing apparatus, and the wafer is divided by the dividing means along a street. It is sectional drawing explaining the state which picks up a chip from a film using a pickup device. It is sectional drawing explaining the case where the film is attached to the ring frame through the annular glue, the opening of the ring frame is closed with the film, and the second frame set is formed. It is sectional drawing which shows the state in which the protective tape attached to the wafer of the 2nd frame set is brought into contact with water dropped on the upper surface of a base. It is sectional drawing explaining the state which the opening of a ring frame and the wafer held by a base are covered with a film from above. It is sectional drawing explaining the case where a wafer and a 2nd frame set are housed in a room, and the room is depressurized. It is sectional drawing explaining the case where a film is pressed against a wafer in a room under reduced pressure, the film or a wafer is heated and heat-bonded without using glue, and a wafer, a ring frame and a film are integrated to form a work set. FIG. 5 is a cross-sectional view illustrating a case where a film having outer peripheral glue is attached to a ring frame via an annular glue and the opening of the ring frame is closed with the film to form a third frame set. It is sectional drawing which shows the state in which the protective tape attached to the wafer of the 3rd frame set is brought into contact with water dropped on the upper surface of a base. It is sectional drawing explaining the state which the opening of a ring frame and the wafer held by a base are covered with a film from above. It is sectional drawing explaining the case where a wafer and a 3rd frame set are housed in a room, and the room is depressurized. In a depressurized room, the film is pressed against the wafer and the outer peripheral glue is adhered to the outer peripheral region of the other surface of the wafer to integrate the wafer, ring frame and film, and the central region of the other surface of the wafer and the film are not adhered. It is sectional drawing explaining the case. A cross-sectional view illustrating a case where the film or wafer is heated after the temporary bonding step, the film and the wafer are heat-bonded without using glue, and the wafer, the ring frame, and the film are integrated to form a work set. is there.

The wafer W shown in FIG. 1 is, for example, a semiconductor wafer having a circular outer shape made of silicon as a base material, and one surface Wa facing downward in FIG. 1 is protected by a protective tape T1. ing. The wafer W may be made of gallium arsenide, sapphire, ceramics, resin, gallium nitride, silicon carbide, or the like in addition to silicon.

One surface Wa of the wafer W is provided with a device region Wa1 and an outer peripheral surplus region Wa2 surrounding the device region Wa1. The device region Wa1 is partitioned in a grid pattern by a plurality of streets S that are orthogonal to each other, and a device D such as an IC is formed in each region partitioned in a grid pattern.

The other surface Wb, which is opposite to one surface Wa of the wafer W in the Z-axis direction, is ground using a known grinding device (see, for example, Patent Document 2). That is, the wafer W is held by the chuck table of the grinding apparatus described in Patent Document 2, for example, via the protective tape T1, and the other surface Wb is ground by a grinding wheel, so that, for example, the thickness is 20 μm or more. It is in a state of being thinned to 100 μm.

The outer peripheral region of the other surface Wb corresponding to the outer peripheral surplus region Wa2 of the wafer W is defined as the outer peripheral region Wb2 of the other surface Wb, and the region inside the outer peripheral region Wb2 of the other surface Wb is the center of the other surface Wb. Let the region Wb1 be used.

The ground wafer W is in a state of having a grinding strain. That is, the wafer W is curved in a hollow shape by gradually warping upward from the central region Wb1 of the other surface Wb toward the outer peripheral region Wb2.

(Embodiment 1)
Hereinafter, each step in the case where the wafer dividing method according to the present invention is carried out and the wafer W shown in FIG. 1 is divided along the street S will be described. This embodiment is referred to as the first embodiment.

(1) Water Supply Process The base 10 shown in FIG. 2 is the base that first holds the wafer W in this division method. The base 10 has, for example, a circular shape having a diameter larger than that of the wafer W in a plan view, and holds the wafer W on a flat upper surface 10a.
For example, a connecting plate 100 extending horizontally outward in the radial direction is connected to the side surface of the base 10, and a ring frame support base 11 having an annular shape in a plan view is fixed to the upper surface of the connecting plate 100. There is. The ring frame support base 11 supports the ring frame on a flat upper surface 11a.
For example, the height of the upper surface 11a of the ring frame support 11 is equal to the upper surface of the ring frame when the wafer W is held by the upper surface 10a of the base 10 and the ring frame is held by the upper surface 11a of the ring frame support 11. The other surface Wb, which is the upper surface of the wafer W, is set to have substantially the same height.

In the water supply step, as shown in FIG. 2, the water supply nozzle 120 communicating with the water supply source 12 that delivers water (for example, pure water) is positioned above the center of the upper surface 10a of the base 10, for example. .. Then, the water supply source 12 sends out the water J1, and an appropriate amount of the water J1 is dropped from the water supply nozzle 120 toward the upper surface 10a. For example, when a predetermined amount of water J1 is deposited in a film shape on the center of the upper surface 10a of the base 10, the water supply nozzle 120 stops the supply of water J1. Then, the water supply nozzle 120 retracts from above the base 10 to the outside.

(2) Holding Step The wafer W shown in FIG. 1 is suction-held by a transfer pad (not shown), the wafer W is edge-clamped by a clamp (not shown), or the wafer W is held and conveyed by an operator, and the wafer W is conveyed. Is positioned above the upper surface 10a of the base 10 as shown in FIG. The wafer W is in a state in which the protective tape T1 is directed downward, and the center of the wafer W and the center of the upper surface 10a of the base 10 are substantially aligned with each other.

After that, the wafer W is lowered toward the upper surface 10a of the base 10, the protective tape T1 attached to the wafer W comes into contact with the water J1 on the upper surface 10a of the base 10, and the upper surface 10a of the base 10 Wafer W is placed on top. As a result, the water J1 on the upper surface 10a is pressed by the wafer W and spreads radially outward between the lower surface of the protective tape T1 and the upper surface 10a attached to one surface Wa which is the lower surface of the wafer W. To go. Then, even if the water J1 spreads between the upper surface 10a of the base 10 and the entire lower surface of the protective tape T1 or the surface tension of the water J1 causes a transport pad or the like (not shown) to separate the wafer W, the wafer W is formed into a hollow shape. The curved wafer W is held in a flat state by the upper surface 10a of the base 10.

(3) Frame Arrangement Process The ring frame F shown in FIG. 4 is made of, for example, SUS or the like and is formed in an annular flat plate shape, and has a circular opening Fc having an inner diameter larger than the outer diameter of the wafer W. There is.
The ring frame F is placed on the upper surface 11a of the ring frame support base 11 by a ring frame transport means (not shown) or an operator, and is supported by the ring frame support base 11. Then, the wafer W held by the base 10 is positioned in the opening Fc of the ring frame F and is surrounded by the ring frame F. The center of the opening Fc of the ring frame F and the center of the wafer W are substantially aligned with each other, and the upper surface of the ring frame F and the other surface Wb which is the upper surface of the wafer W are positioned at substantially the same height. Become.

(4) Film Arrangement Process The film T2 shown in FIG. 5 is a polyolefin-based resin film, has flexibility, and has flat front and back surfaces. The film T2 has a diameter larger than the inner diameter of the opening Fc of the ring frame F, and does not include a glue layer on which the wafer W is attached. The film T2 is a polymer sheet synthesized using an alkene as a monomer, and is, for example, a polyethylene sheet, a polypropylene sheet, or the like, which is transparent or translucent to visible light. However, the polyolefin-based film T2 is not limited to this, and may be opaque.

Since the polyolefin-based film T2 does not have a glue layer, it cannot be attached to the wafer W at room temperature. However, since the polyolefin-based film T2 has thermoplasticity, when it is heated to a temperature near the melting point in a state where it is bonded to the wafer W while applying a predetermined pressure and pressed, it can be partially melted and adhered to the wafer W. .. The heating temperature of the polyethylene film is 120 ° C. to 140 ° C., and the heating temperature of the polypropylene film is 160 ° C. to 180 ° C.

The film T2 shown in FIG. 5 may be a polyester-based resin film. The polyester-based film T2 is a polymer film synthesized by using a dicarboxylic acid (a compound having two carboxyl groups) and a diol (a compound having two hydroxyl groups) as monomers. For example, a polyethylene terephthalate film, Alternatively, it is a film that is transparent or translucent to visible light, such as a polyethylene naphthalate film. However, the polyester-based film T2 is not limited to this, and may be opaque.

Since the polyester-based film T2 does not have a glue layer, it cannot be attached to the wafer W at room temperature. However, since the polyester-based film T2 has thermoplasticity, when it is heated to a temperature near the melting point in a state where it is bonded to the wafer W while applying a predetermined pressure and pressed, it can be partially melted and adhered to the wafer W. ..

Further, the film T2 may be a polystyrene film having no glue layer, and the heating temperature of the film T2 in this case is 220 ° C. to 240 ° C.

In the film arranging step, as shown in FIG. 5, the films T2 conveyed by the film conveying means (not shown) are positioned above the wafer W so that their centers are substantially aligned with each other. Then, the film T2 is lowered, and the opening Fc of the ring frame F and the wafer W held by the base 10 are covered with the film T2.

(5) Decompression Step Next, for example, the base 10 holding the wafer W is carried into the chamber 2 shown in FIG. The base 10 is housed in the chamber 2 in advance, and (1) the water supply step to (4) the film placement step may be performed in the chamber 2.

The chamber 2 is, for example, a vacuum chamber capable of creating a vacuum atmosphere in the internal space, and the top plate 20 of the chamber 2 is provided with a suction pipe 200 communicating with the inside of the chamber 2. A vacuum pump 201 that sucks the air in the chamber 2 is connected to the 200. By operating the vacuum pump 201, the inside of the chamber 2 can be depressurized to a predetermined vacuum atmosphere.

The side wall 21 of the chamber 2 is provided with a carry-in outlet 211 and a shutter 212 for opening and closing the carry-in outlet 211, and the shutter 212 can be raised and lowered by a shutter raising and lowering means 213 such as a cylinder mechanism.

Above the base 10 and the ring frame support 11 located on the bottom plate 22 of the chamber 2, a circular pressing pad 23 having a built-in heater 230 is arranged. The pressing pad 23 is formed to have a diameter larger than the outer diameter of the ring frame support base 11, for example. The heater 230 to which the power supply 231 is connected is, for example, a heat transfer heater composed of a heat transfer wire or the like, but is not limited to this, and a heater 230 capable of heating the film T2 or the wafer W in a short time is preferable.
The pressing pad 23 can be raised and lowered in the chamber 2 by a pad raising and lowering means 24 such as a cylinder mechanism.

In the depressurizing step, the shutter 212 shown in FIG. 6 is closed by the shutter elevating means 213, air in the chamber 2 is sucked by the vacuum pump 201, and the wafer W, the ring frame F, the film T2, and the base 10 are sucked. The inside of the chamber 2 in which the above is housed is decompressed to, for example, a vacuum atmosphere.

(6) Integrated forming step Next, in the chamber 2 which has been decompressed to create a vacuum atmosphere, for example, the pad elevating means 24 lowers the pressing pad 23 at a predetermined lowering speed, and the pressing pad 23 wafers the film T2. The film T2 is pressed against the upper surface of the ring frame F by the pressing pad 23 while being pressed against the other surface Wb which is the upper surface of W. Since the inside of the chamber 2 is decompressed to create a vacuum atmosphere, for example, air may enter between the film T2 and the other surface Wb of the wafer W and between the film T2 and the upper surface of the ring frame F. There is no. Further, since the wafer W that has been curved in a hollow shape due to the surface tension of the water J1 is held by the upper surface 10a of the base 10 in a flat state, the film T2 is the other surface of the wafer W. It is pressed against the entire surface of Wb.
Since the wafer W is pressed against the film T2 by the pressing pad 23 in the chamber 2 which has been decompressed and has a vacuum atmosphere, for example, the water J1 is not vaporized by the decompression in the chamber 2 and disappears.

In this state, the heater 230 to which power is supplied from the power supply 231 generates heat, and in the present embodiment, the film T2 and the wafer W are at a predetermined temperature via the pressing pad 23, that is, the film T2 is a polyethylene film. In the case, the film T2 is heated to 100 ° C. to 140 ° C., and the film T2 and the wafer W are heat-bonded without using glue. Further, in the present embodiment, the film T2 and the ring frame F are thermally bonded to each other via the pressing pad 23. Then, a work set WS in which the wafer W, the ring frame F, and the film T2 are integrated is formed.

The heater 230 does not have to be arranged in the pressing pad 23 as long as it can heat at least one of the film T2 and the wafer W, and at least one of the film T2 and the ring frame F. For example, the heater may be a far-infrared heater, and the film T2 pressed by the pressing pad 23 may be directly irradiated with infrared rays from the heater to heat the film.

(7) Protective tape peeling step The work set WS is taken out from the chamber 2 where the normal pressure is returned by a carry-out pad (not shown) or an operator. The work set WS may be taken out from the room 2 together with the base 10, or only the work set WS may be taken out from the room 2 as shown in FIG. For example, when the work set WS is separated from the base 10, since the wafer W is held by the surface tension of the water J1 on the base 10, air is allowed to enter between the upper surface 10a and the film T2. And it can be done easily. Then, for example, as shown in FIG. 9, the work set WS was sucked and held by the tape release table 30 with the protective tape T1 turned upside down and turned upward, or was arranged around the tape release table 30. The ring frame F is clamped and fixed by a fixing clamp (not shown).

For example, as shown in FIG. 9, at least one of the tape peeling clamp 31 and the tape peeling table 30 moves relatively in the horizontal direction while the tape peeling clamp 31 grips the outer peripheral edge of the protective tape T1. Then, the protective tape T1 is pulled by the tape peeling clamp 31 and peeled from one surface Wa of the wafer W.
The protective tape T1 may be peeled from the wafer W by attaching the peeling tape to the protective tape T1 and pulling the peeling tape.

(8) Dividing Step The work set WS from which the protective tape T1 has been peeled off by a carry-out pad or an operator (not shown) is conveyed to the dividing device 4 shown in FIG. The dividing device 4 shown in FIG. 10 is, for example, a cutting device including a rotating cutting blade 40 which is a dividing means and a chuck table 41 capable of sucking and holding a work set WS on a flat holding surface 410. The wafer W may be a laser processing apparatus capable of dividing the wafer W by laser irradiation.

In the dividing device 4, the work set WS is suction-held on the holding surface 410 of the chuck table 41 with the wafer W facing upward. Then, the wafer W is cut along the street S by the rotating cutting blade 40, and is divided into individual chips C (see FIG. 11) including the device D.

Next, the work set WS is conveyed from the dividing device 4 to the pickup device 5 shown in FIG. In the pickup device 5, the ring frame F is fixed by a clamp or the like (not shown), and for example, the tip C is pushed up from below through the film T2 by a needle 50 that can move up and down in the Z-axis direction, and the tip C is lifted from the film T2. It is a device that sucks and holds the tip with a suction pad 51 and picks it up.

In the pickup from the film T2 of the chip C using the pickup device 5, since the film T2 is not attached to the chip C by the glue layer, the adhesive residue on the chip C when the chip C is peeled from the film T2. Will not occur.

(Embodiment 2)
Hereinafter, each step in the case where the wafer dividing method according to the present invention is carried out and the wafer W shown in FIG. 1 is divided along the street S will be described. This embodiment is referred to as Embodiment 2.

The film T3 shown in FIG. 12 (hereinafter referred to as a film T3 with an annular glue) used in the wafer dividing method of the second embodiment has, for example, an annular glue P1 corresponding to the ring frame F arranged on the film T2 described above. It was set up. That is, in the film T3 with cyclic glue, glue P1 having a predetermined thickness is formed in an annular shape in the outer peripheral region of the lower surface in FIG. The type of the glue P1 is not particularly limited, but for example, a UV-curable glue that is cured by irradiation with ultraviolet rays and whose adhesive strength is lowered may be used.

(1) Frameset forming step In the wafer dividing method of the second embodiment, first, a frameset forming step is carried out.
That is, as shown in FIG. 12, on a table (not shown), the film T3 with cyclic glue was attached to the ring frame F via the glue P1, and the opening Fc of the ring frame F was closed with the film T3 with cyclic glue. A frame set FS2 (hereinafter referred to as a second frame set FS2) is formed. In the second frame set FS2, the center of the opening Fc of the ring frame F and the center of the film T2 are substantially aligned with each other.
In this way, by making the annular glued film T3 a second frame set FS2 that can be handled via the ring frame F, the annular glued film T3 is handled via the ring frame F in each step to be performed later. Therefore, the film T3 with cyclic glue can be easily handled.

(2) Water supply step, (3) Holding step, (4) Frame placement step, and (5) Film placement step The water supply step, holding step, frame placement step, and film placement step described in the first embodiment include: Also in the second embodiment, it is carried out in substantially the same manner.
That is, as shown in FIG. 13, the water supply step is carried out, the water J1 is dropped on the upper surface 10a of the base 10 for holding the wafer W, and the water J1 is deposited in the form of a film, and then the holding step is carried out. The protective tape T1 attached to the wafer W comes into contact with the water J1 on the upper surface 10a of the base 10, and the wafer W is placed on the upper surface 10a of the base 10. Then, due to the surface tension of the water J1, the wafer W that has been curved in the shape of a hollow is brought into a state of being held by the upper surface 10a of the base 10 in a flat state.

Further, the frame arranging step and the film arranging step are carried out in parallel. That is, as shown in FIG. 14, the ring frame F of the second frame set FS2 is placed on the upper surface 11a of the ring frame support base 11 by a ring frame transport means (not shown) or an operator, and the ring frame support base 11 is placed. Supported by. Then, the wafer W held by the base 10 is positioned in the opening Fc of the ring frame F and is surrounded by the ring frame F. The center of the opening Fc of the ring frame F and the center of the wafer W substantially coincide with each other. Further, the opening Fc of the ring frame F and the wafer W held by the base 10 are covered with the polyolefin-based film T3 with cyclic glue.

(6) Decompression Step Next, as shown in FIG. 15, for example, a base 10 holding the wafer W and a ring frame support base 11 for supporting the second frame set FS2 are carried into the chamber 2. The base 10 and the ring frame support base 11 are housed in the chamber 2 in advance, and (2) the water supply step to (5) the film placement step may be performed in the chamber 2.
Further, the frame set forming step described above may be carried out at least before the main decompression step, and may not be carried out at the very beginning as in the wafer dividing method of the second embodiment. ..

The shutter 212 shown in FIG. 15 was closed by the shutter elevating means 213, air was sucked into the chamber 2 by the vacuum pump 201, and the wafer W, the second frame set FS2, the base 10, and the like were housed. The inside of the chamber 2 is depressurized to, for example, a vacuum atmosphere.

(7) Integrated forming step Next, in the chamber 2 which has been decompressed to create a vacuum atmosphere, for example, the pad elevating means 24 lowers the pressing pad 23 at a predetermined descending speed and presses the pressing pad 23 as shown in FIG. The pad 23 presses the glue-free region of the annular glue-bearing film T3 against the other surface Wb, which is the upper surface of the wafer W. Since the inside of the chamber 2 is decompressed to create a vacuum atmosphere, air does not enter between the film T3 with cyclic glue and the other surface Wb of the wafer W. Further, since the wafer W curved in the shape of a hollow due to the surface tension of the water J1 is held by the upper surface 10a of the base 10 in a flat state, the film T3 with the annular glue does not have the glue. The region is pressed against the entire surface Wb of the other surface of the wafer W.

In this state, the heater 230 to which power is supplied from the power supply 231 generates heat, and in the present embodiment, the glue-free region of the film T3 with cyclic glue and the wafer W are at a predetermined temperature, that is, via the pressing pad 23. When the film T3 with cyclic glue is a polyethylene film, it is heated to 100 ° C. to 140 ° C., and the glue-free region of the film T3 with cyclic glue and the wafer W are heat-bonded without using glue. The wafer W, the ring frame F, and the film T3 with annular glue are integrated to form a work set.

The heater 230 does not have to be arranged in the pressing pad 23 as long as it can heat at least one of the glue-free region of the annular glue film T3 or the wafer W. For example, the heater is placed in the far infrared ray. As the heater, infrared rays may be directly irradiated from the heater to the glue-free region of the annular glue-bearing film T3 pressed by the pressing pad 23 to heat the film.

(8) Protective Tape Peeling Step to (9) Split Step The protective tape peeling step and the splitting step described in the first embodiment are carried out in substantially the same manner in the second embodiment. Then, the wafer W shown in FIG. 16 is divided into individual chips including the device D, and the chips are picked up by, for example, the pickup device 5 shown in FIG.

In the pickup from the annular glue film T3 of the chip using the pickup device 5, the chip on which the wafer W is divided is not attached to the annular glue film T3 by glue, so that the annular glue film T3 No adhesive residue is generated on the chip when the chip is peeled off from the chip.

(Embodiment 3)
Hereinafter, each step in the case where the wafer dividing method according to the present invention is carried out and the wafer W shown in FIG. 1 is divided along the street S will be described. This embodiment is referred to as the third embodiment.

The film T4 shown in FIG. 17 (hereinafter referred to as a film T4 with outer peripheral glue) used in the wafer dividing method of the third embodiment has, for example, an annular glue P1 corresponding to the ring frame F arranged on the film T2 described above. An annular outer peripheral glue P2 corresponding to the outer peripheral region Wb2 of the other surface Wb of the wafer W shown in FIG. 1 is arranged. That is, in the film T4 with outer peripheral glue, the glue P1 having a predetermined thickness is formed in an annular shape in the outer peripheral region of the lower surface in FIG. The outer peripheral glue P2 having a predetermined thickness is formed in an annular shape. The types of the glue P1 and the outer peripheral glue P2 are not particularly limited, but for example, a UV-curable glue that is cured by irradiation with ultraviolet rays and whose adhesive strength is lowered may be used.

(1) Frameset forming step In the wafer dividing method of the third embodiment, first, a frameset forming step is carried out.
That is, as shown in FIG. 17, on a table (not shown), the outer peripheral glued film T4 was attached to the ring frame F via the glue P1, and the opening Fc of the ring frame F was closed by the outer peripheral glued film T4. A frame set FS3 (hereinafter referred to as a third frame set FS3) is formed. In the third frame set FS3, the center of the opening Fc of the ring frame F and the center of the film T2 are substantially aligned with each other.
In this way, by making the outer peripheral glued film T4 a third frame set FS3 that can be handled via the ring frame F, the outer peripheral glued film T4 is handled via the ring frame F in each step to be performed later. Therefore, the film T4 with outer peripheral glue can be easily handled.

(2) Water supply step, (3) Holding step, (4) Frame placement step, and (5) Film placement step The water supply step, holding step, frame placement step, and film placement step described in the first embodiment include: In the third embodiment, it is carried out in substantially the same manner.
That is, as shown in FIG. 18, a water supply step is carried out, water J1 is dropped on the upper surface 10a of the base 10 for holding the wafer W, water J1 is deposited in a film shape, and then the holding step is carried out. The protective tape T1 attached to the wafer W comes into contact with the water J1 on the upper surface 10a of the base 10, and the wafer W is placed on the upper surface 10a of the base 10. Then, due to the surface tension of the water J1, the wafer W that has been curved in the shape of a hollow is brought into a state of being held by the upper surface 10a of the base 10 in a flat state.

Further, the frame arranging step and the film arranging step are carried out in parallel. That is, as shown in FIG. 19, the ring frame F of the third frame set FS3 is placed on the upper surface 11a of the ring frame support 11 by a ring frame transport means (not shown) or an operator, and the ring frame support 11 Supported by. Then, the wafer W held by the base 10 is positioned in the opening Fc of the ring frame F and is surrounded by the ring frame F. The center of the opening Fc of the ring frame F and the center of the wafer W are substantially aligned with each other. Further, the opening Fc of the ring frame F and the wafer W held by the base 10 are covered with the polyolefin-based film T4 having outer peripheral glue.
By performing the frame arranging step and the film arranging step, the outer peripheral glue P2 may come into contact with the outer peripheral region Wb2 of the other surface Wb of the wafer W, or is positioned above the outer peripheral region Wb2. May become.

(6) Decompression Step Next, as shown in FIG. 20, for example, a base 10 holding the wafer W and a ring frame support base 11 for supporting the third frame set FS3 are carried into the chamber 2. The base 10 and the ring frame support base 11 are housed in the chamber 2 in advance, and (2) the water supply step to (5) the film placement step may be performed in the chamber 2.
Further, the frame set forming step described above may be carried out at least before the main decompression step, and may not be carried out at the beginning as in the wafer dividing method of the third embodiment. ..

The shutter 212 shown in FIG. 20 was closed by the shutter elevating means 213, air was sucked into the chamber 2 by the vacuum pump 201, and the wafer W, the third frame set FS3, the base 10, and the like were housed. The inside of the room 2 becomes a vacuum atmosphere, for example.

(7-1) Temporary Adhesion Step in the Integrated Forming Step The pressing pad 23A shown in FIG. 20 has, for example, a configuration not provided with a heater inside.
Next, in the chamber 2 where the pressure is reduced to create a vacuum atmosphere, for example, the pad elevating means 24 lowers the pressing pad 23A at a predetermined lowering speed, and the pressing pad 23A presses the outer peripheral glued film T4 against the wafer W. The outer peripheral glue P2 of the film T4 with the outer peripheral glue is adhered to the outer peripheral region Wb2 of the other surface Wb of the wafer W. As a result, the wafer W, the ring frame F, and the outer peripheral glued film T4 are integrated, and the central region Wb1 of the other surface Wb of the wafer W and the outer peripheral glued film T4 are not adhered to each other. Since the inside of the chamber 2 is decompressed to create a vacuum atmosphere, for example, air does not enter between the film T4 with outer peripheral glue and the other surface Wb of the wafer W.

(7-2) Thermal bonding step in the integral forming step The wafer W integrated with the ring frame F and the outer peripheral glued film T4 is taken out from the chamber 2 returned to normal pressure by a carry-out pad or an operator (not shown). Is done. When the wafer W is separated from the base 10, the wafer W is held by the surface tension of the water J1 on the base 10, so that air enters between the upper surface 10a and the outer peripheral glued film T4. It can be easily done by making it.
After that, for example, as shown in FIG. 22, the wafer W integrated with the ring frame F and the outer peripheral glued film T4 is turned upside down on the heater table 60 and suction-held with the protective tape T1 facing upward. The ring frame F is clamped and fixed by a fixed clamp (not shown) which is clamped or arranged around the heater table 60.

The heater table 60 includes, for example, a heater 600 to which a power supply 601 is connected. The heater 600 is, for example, a heat transfer heater composed of a heat transfer wire or the like, but is not limited to this, and a heater 600 capable of heating the film T4 with outer peripheral glue or the wafer W in a short time is preferable.
The heater 600 to which power is supplied from the power supply 601 generates heat, and in the present embodiment, the glue-free region corresponding to the central region Wb1 of the other surface Wb of the wafer W of the film T4 with outer peripheral glue and the wafer W are predetermined. That is, when the outer peripheral glued film T4 is a polyethylene film, it is heated to 100 ° C. to 140 ° C., and the glue-free region of the outer peripheral glued film T4 and the wafer W are heat-bonded without using glue. As a result, the wafer W, the ring frame F, and the outer peripheral glued film T4 are integrated to form a work set.

Since the heater 600 only needs to be able to heat at least one of the outer peripheral glued film T4 and the wafer W, it does not have to be arranged on the heater table 60. For example, the heater is a far-infrared heater of the wafer W. The film T4 with outer peripheral glue may be directly irradiated with far infrared rays from above to heat the film T4.

(8) Protective Tape Peeling Step to (9) Split Step The protective tape peeling step and the splitting step described in the first embodiment are carried out in substantially the same manner in the third embodiment. Then, the wafer W shown in FIG. 22 is divided into individual chips including the device D, and the chips are picked up by, for example, the pickup device 5 shown in FIG.

In the pickup from the film T4 with the outer peripheral glue of the chip using the pickup device 5, the chip on which the wafer W is divided is not attached to the film T4 with the outer peripheral glue by glue, so that the film T4 with the outer peripheral glue is not attached. No adhesive residue is generated on the chip when the chip is peeled off from the chip.

The method for dividing the wafer according to the present invention is not limited to the above-described first, second, and third embodiments, and the configuration of each device shown in the attached drawings is not limited to this. It can be changed as appropriate within the range in which the effect of the present invention can be exhibited.

W: Wafer Wa: One surface S: Street D: Device Wa1: Device area Wa2: Outer peripheral surplus area Wb: Other surface Wb1: Central area Wb2: Outer area T1: Protective tape 10: Base 11: Ring frame support 12: Water supply source J1: Water F: Ring frame T2: Film 2: Room 201: Vacuum pump 23: Pressing pad 230: Heater 24: Pad raising and lowering means
30: Tape peeling table 31: Tape peeling clamp 4: Splitting device 40: Cutting blade 41: Chuck table 5: Pickup device 50: Needle 51: Suction pad T3: Film with annular glue P1: Circular glue T4: Film with outer peripheral glue P1: Circular glue P2: Outer glue 60: Heater table

Claims (4)

A protective tape is attached to one surface of a wafer having a grid-like street for partitioning a plurality of devices formed on one surface, and is held by a chuck table via the protective tape with respect to the one surface. It is a method of dividing a wafer in which the other surface on the opposite side is ground with a grinding wheel and the wafer is divided by a dividing means along the street.
A water supply process in which water is dropped onto the upper surface of a base for holding the wafer, and
The protective tape attached to the wafer is brought into contact with the water dropped on the upper surface of the base, the water is distributed between the upper surface of the base and the protective tape, and the surface tension of the water is increased. A holding step of flattening the wafer and holding it on the upper surface of the base.
A frame arranging step of supporting a ring frame having an opening having an inner diameter larger than the outer diameter of the wafer on the ring frame support base so as to surround the wafer held on the base and positioning the wafer at substantially the same height as the wafer.
A film arranging step of covering the opening of the ring frame and the wafer held by the base with a polyolefin-based film from above.
A decompression step of accommodating the wafer, the ring frame, and the film in a room and depressurizing the room.
In the depressurized room, the film is pressed against the wafer to heat the film or the wafer, the film and the wafer are heat-bonded without using glue, and the film and the ring frame are further bonded. An integral forming step of forming a work set by integrating the wafer, the ring frame, and the film.
A protective tape peeling step of removing the work set from the chamber and peeling the protective tape attached to one surface thereof.
A method for dividing a wafer, comprising a dividing step of holding the work set from which the protective tape has been peeled off on a chuck table of a dividing device and dividing the wafer by the dividing means along the street. The method for dividing a wafer according to claim 1, wherein the integral forming step is a method of dividing a wafer according to claim 1, wherein the film is pressed against the ring frame to heat the film or the ring frame, and the film and the ring frame are thermally bonded to each other. The film comprises an annular glue corresponding to the ring frame.
Prior to the depressurization step, a frame set forming step of attaching the film to the ring frame via the glue and closing the opening of the ring frame with the film to form a frame set.
In the decompression step, the wafer and the frame set are housed in the chamber, and the chamber is depressurized.
In the integral forming step, the film is pressed against the wafer in the depressurized chamber to heat the film or the wafer, and the film and the wafer are heat-bonded without using glue, and the wafer and the ring are bonded to each other without using glue. The method for dividing a wafer according to claim 1, wherein the frame and the film are integrated to form the work set. The film comprises an annular glue corresponding to the ring frame and an annular outer peripheral region corresponding to the outer peripheral region of the other surface of the wafer.
Prior to the depressurization step, a frame set forming step of attaching the film to the ring frame via the glue and closing the opening of the ring frame with the film to form a frame set.
In the decompression step, the wafer and the frame set are housed in the chamber, and the chamber is depressurized.
In the integral forming step, the film is pressed against the wafer in the depressurized chamber, the outer peripheral adhesive is adhered to the outer peripheral region of the other surface of the wafer, and the wafer, the ring frame, and the film are integrated. After the temporary bonding step in which the central region of the other surface of the wafer and the film are not bonded and the temporary bonding step, the film or the wafer is heated, and the film and the wafer are bonded without using glue. The method for dividing a wafer according to claim 1, further comprising a heat-bonding step of forming the work set by heat-bonding the wafer to the ring frame and the film.

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