CN103681492B - processing method - Google Patents

Abstract

The present invention provides a processing method capable of completely preventing debris of the adhesive sheet from adhering to the surface of the plate when expanding and dividing a plate-shaped object such as a wafer with an adhesive sheet attached to its back. When expanding the expansion tape (13) in a state where the wafer (1) is placed on the expansion tape (13) via the adhesive sheet (12) to divide the wafer (1) into chips (3), the protective member ( 11) It is attached to the surface (1a) of the wafer (1), and the protruding portion (12a) of the adhesive sheet (12) protruding toward the outer peripheral side of the wafer (1) is split (first expansion step), followed by Next, remove the protective member (11) (protective member removal step), further expand the expansion tape, and divide the wafer and the adhesive sheet along the dividing line to obtain a plurality of chips with the adhesive sheet (second expansion step). Chips of the adhesive sheet generated when the adhesive sheet is split are attached to the protective member to prevent the chips from adhering to the surface of the wafer.

Description

processing method

technical field

The present invention relates to a processing method for dividing a thin plate-shaped object such as a semiconductor wafer into a plurality of chips, and particularly relates to a processing method for a plate-shaped object on which an adhesive sheet is pasted.

Background technique

A disk-shaped wafer such as a semiconductor wafer having a plurality of devices formed on its surface is divided along planned dividing lines between the devices, and is singulated into semiconductor chips. In addition, in order to form the adhesive layer when mounting the chip on the back surface in advance, there is provided a technology in which an adhesive sheet for forming an adhesive layer such as DAF (Die Attach Film) is attached to the back surface of the wafer , split the wafer. In this case, the adhesive sheet is formed to have a diameter slightly larger than that of the wafer, and a part of the adhesive sheet attached to the back surface of the wafer protrudes from the outer periphery of the wafer.

When dividing the wafer, the adhesive sheet is divided together with the wafer, but when the method of dividing the wafer by applying an external force to the wafer by expanding the expansion tape or the like pasted on the wafer, wherein the above-mentioned wafer has a division along the planned dividing line Starting point, there is a problem that the portion protruding from the outer periphery of the wafer is also split, and debris of the adhesive sheet generated at that time adheres to the surface of the wafer.

Therefore, in order to solve this problem, a technique has been proposed in which air is blown onto the wafer surface from an air blowing member during expansion of the expansion sheet so that debris of the adhesive sheet does not adhere to the wafer surface (Patent Document 1).

prior art literature

Patent Document 1: Japanese Patent Laid-Open No. 2009-272503

However, even with the techniques described in the above documents, it is difficult to completely prevent the debris of the adhesive sheet from adhering to the wafer surface.

Contents of the invention

The present invention was made in view of the above, and its main technical task is to provide a processing method that can completely prevent sticking when expanding and dividing a plate-shaped object such as a wafer with an adhesive sheet attached on the back surface. Fragments of the flakes adhere to the surface of the plate.

The processing method of the present invention is a processing method for a plate-shaped object provided with a protective member on the surface and a starting point for division along the planned dividing line. The above-mentioned processing method is characterized in that it has the following step: The adhesive sheet disposes the plate on the expansion belt; the first expansion step is to expand the expansion belt in the state where the protective member is arranged on the surface of the plate after the above-mentioned sticking step is carried out, thereby The above-mentioned adhesive sheet protruding to the outer peripheral side of the plate is split; the protective member removing step is to remove the above-mentioned protective member arranged on the surface of the plate after the above-mentioned first expansion step; and the second expansion step , after implementing the step of removing the protective member, expanding the expanded band, dividing the plate from the starting point of division along the planned dividing line, and breaking the adhesive sheet corresponding to the plate along the planned dividing line .

In the processing method of the present invention, the first expanding step is completed with the protective member disposed on the surface of the plate, and at least the adhesive sheet protruding toward the outer peripheral side of the plate is broken at this point. Fragments of the adhesive sheet generated at the time of breakage adhere to the protective member. After the first expanding step is performed, since the protective member to which debris is attached is removed from the plate, it is possible to completely prevent debris from adhering to the surface of the plate.

In the present invention, the method includes a mode in which the above-mentioned processing method has a ring-shaped frame sticking step, and in the ring-shaped frame sticking step, after the second expansion step is performed, one formed by dividing the plate is maintained. In the state where the gap between the individual chips is maintained, the annular frame is attached to the above-mentioned expansion tape, and a plurality of the above-mentioned chips formed by dividing the plate-shaped object are stored in the opening of the above-mentioned annular frame. According to this aspect, the interval between the divided chips is maintained, and the chips can be transported without being damaged by handling the ring frame.

Invention effect

According to the present invention, there is provided a processing method capable of completely preventing debris of the adhesive sheet from adhering to the surface of the plate when expanding and dividing a plate-shaped object such as a wafer with an adhesive sheet attached on its back.

Description of drawings

FIG. 1 is a perspective view showing a step of attaching a protective member in a processing method according to an embodiment of the present invention.

Fig. 2 is a perspective view showing a back grinding step of the machining method according to the embodiment.

FIG. 3 is a perspective view showing a modified layer forming step in a processing method according to an embodiment.

Fig. 4 is a partial sectional view of a wafer showing details of a modified layer forming step.

Fig. 5 is a perspective view showing a pasting step of a processing method according to an embodiment.

Fig. 6 is a perspective view showing a first expanding step of the processing method according to the embodiment.

Fig. 7 is a sectional view showing a first expansion step.

Fig. 8 is a perspective view showing the state after the first expansion step.

9 is a perspective view showing a step of removing a protective member in a processing method according to an embodiment.

Fig. 10 is a perspective view showing a second expanding step of the processing method according to the embodiment.

Fig. 11 is a sectional view showing a second expansion step.

In FIG. 12 , (a) is a cross-sectional view showing the step of sticking the ring frame in the processing method according to one embodiment, and (b) is a cross-sectional view showing cutting of the expansion tape after the step of sticking the ring frame.

13 is a perspective view showing a state in which wafers are carried out from the expansion apparatus after the expansion tape is cut.

14 is a perspective view showing an expanding apparatus according to another embodiment, wherein (a) shows a state where a wafer is set, (b) shows a state where a first expanding step is performed, and (c) shows a state where a second expanding step is performed.

Label description

1...wafer (plate)

1a...The surface of the wafer

1c...modified layer (splitting starting point)

3...chip

11...protection parts

12...Adhesive sheet

12a...Protruding part of the adhesive sheet

13...Extension belt

14...ring frame

14a... Opening of the ring frame.

detailed description

Hereinafter, a wafer processing method including an embodiment of the processing method of the present invention will be described with reference to the drawings.

(1) Pasting steps of protective parts

As shown in FIG. 1 , the protective member 11 is attached to the entire surface 1 a of a disk-shaped wafer (plate-like object) 1 such as a semiconductor wafer. On the surface (the lower surface side in FIG. 1 is the surface) 1a of the wafer 1, a plurality of planned dividing lines are set in a grid pattern, and each device region having a plurality of rectangular shapes divided by the planned dividing lines is formed with an LSI. (Large-scale integrated circuits) and other electronic circuit devices 2. For the protective tape 11 , for example, a flexible resin sheet having an adhesive layer formed on one surface thereof is used as the protective member 11 , and the protective member 11 is pasted so as to cover the surface 1 a of the wafer 1 via the adhesive layer. As the protection member 11 , a hard board such as a silicon wafer, a glass substrate, or a ceramic substrate may be used, and affixed to the wafer with an adhesive or the like.

(2) Back grinding step

Next, as shown in FIG. 2, the wafer 1 is held by the holding table 21 by aligning the protective member 11 side with the holding table 21, and the back surface 1b of the wafer 1 exposed upward is ground by the grinding member 22, thereby making The wafer 1 is thinned to a predetermined thickness (for example, about 50 to 100 μm).

The holding table 21 is a generally well-known negative pressure chuck table that adsorbs and holds the workpiece on a circular horizontal holding surface formed of a porous material through the negative pressure effect generated by air suction. The rotary driving mechanism is used to make the holding table 21 rotate around the axis. The grinding member 22 is a member in which a grinding wheel 25 is fixed via a flange 24 to the end of a main shaft 23 extending in the vertical direction and rotationally driven by a motor not shown, and the grinding member 22 is vertically movably arranged. On the top of the holding table 21. A plurality of grindstones 26 are arranged and fastened in a ring shape on the outer peripheral portion of the lower surface of the grinding wheel 25 . The grindstone 26 is made of a material corresponding to the material of the wafer 1 , for example, a diamond grindstone formed by aggregating diamond abrasive grains with a binder such as a metal bond or a resin bond is used.

In the grinding step, the wafer 1 is loaded on the holding table 21 with the side of the protective member 11 aligned with the holding surface, and the wafer 1 is sucked and held by the negative pressure chuck. Then, from the state where the holding table 21 rotates in one direction at a predetermined speed, the grinding member 22 is lowered, and the grinding wheel 26 of the rotating grinding wheel 25 is pressed against the back surface 1b of the wafer 1, thereby performing grinding on the entire surface of the back surface 1b. grinding.

(3) Modified layer formation step

Next, a laser beam having a wavelength that is transparent to the wafer 1 is irradiated along the planned dividing line to form a reformed layer along the planned dividing line inside the wafer 1 . As shown in FIG. 3 , regarding the formation of the reformed layer, the protective member 11 side is aligned with the holding surface of the negative pressure chuck type holding table 31 which is rotatable as the above-mentioned holding table 21, and the wafer 1 is loaded on it. On the holding table 31, the wafer 1 is sucked and held by a negative pressure chuck. And, as shown in FIG. 4 , in the state where the focal point is positioned inside the wafer 1 , from the irradiation portion 33 of the laser irradiation member 32 arranged above the holding table 31 , from the side of the ground back surface 1 b , and irradiate the laser beam L having a wavelength that is transparent to the wafer 1 along the planned dividing line, thereby forming the modified layer 1c.

The holding table 31 is movable in the X direction and the Y direction shown in FIG. 3 , and the laser beam L is scanned on the wafer 1 by, for example, processing feed that moves the holding table 31 in the X direction. In this case, the planned dividing line on which the laser beam L is irradiated is selected by index feed that moves the holding table 31 in the Y direction. In addition, the holding table 31 is rotated so that the planned dividing line is in a state along the X direction. The modified layer 1 c is formed at a position at a certain depth from a surface to be irradiated with the laser beam L (back surface 1 b of the wafer 1 ) and has a constant layer thickness. Modified layer 1c has a property of being lower in strength than other parts in wafer 1, and serves as a starting point for dividing wafer 1 in the subsequent second expansion step.

(4) Paste step

Next, as shown in FIG. 5 , the rear surface 1 b side of the wafer 1 is placed on the expansion tape 13 via the adhesive sheet 12 having a larger diameter than the wafer 1 . The extended tape 13 is, for example, an extended tape with an adhesive layer formed on one side of a stretchable synthetic resin sheet such as polyvinyl chloride or polyolefin. In this case, a rectangular extended tape larger than the wafer 1 is used or wound into a roll. Cylindrical extension strap.

In the attaching step, an adhesive sheet 12 made of DAF or the like is arranged in a circular shape on the adhesive layer side of the extension tape 13 , and then the wafer 1 is aligned and attached to the adhesive sheet 12 on the back side 1b side. In addition, the wafer 1 may be pasted on the extension tape 13 provided with the circular adhesive sheet 12 in advance. Alternatively, the adhesive sheet 12 may be attached to the back surface 1 b of the wafer 1 , and then the adhesive sheet 12 may be attached to the adhesive layer of the extension tape 13 . The adhesive sheet 12 is formed in a circular shape with a diameter larger than that of the wafer 1 , and a protruding portion 12 a of the adhesive sheet 12 is formed on the outer peripheral side of the wafer 1 .

(5) The first expansion step

Next, the expansion tape 13 is expanded while the protective member 11 is disposed on the surface 1 a of the wafer 1 , and the protruding portion 12 a of the adhesive sheet 12 protruding toward the outer peripheral side of the wafer 1 is split.

In the first expansion step, the expansion device 40 shown in FIGS. 6 and 7 is used. The expansion device 40 has clamping members 41 that hold the end edges of the four sides of the expansion belt 13 and pull them outward perpendicular to the end edges. The clamp member 41 has a structure obtained by combining frames 42 having an L-shaped cross section in a vertically symmetrical state, and a plurality of rollers 43 are closely arranged inside each frame 42 . These rollers 43 are supported by the frame 42 so as to be rotatable about a rotation axis perpendicular to the longitudinal direction of the frame 42 . The expansion belt 13 is sandwiched between the upper and lower rollers 43 , and when the expansion belt 13 is stretched in the direction along the edge in the sandwiched state, the rollers 43 roll along therewith.

Regarding the expansion of the expansion belt 13, at first, the end edges of the four sides of the expansion belt 13 are passed between the upper and lower frames 42 of each clamping part 41 of the expansion device 40, the upper and lower frames 42 are close to each other, and the upper and lower rollers are passed 43 to clamp the expansion band 13. Next, the clamp member 41 is moved outward (direction of arrows in FIGS. 6 and 7 ) to expand the extension band 13 . Even if an unbalanced deformation occurs in the expansion belt 13 due to expansion due to clamping by the rollers 43 of the clamp member 41, the deformation can be released by rolling the rollers 43, and the expansion belt 13 can be uniformly expanded.

As shown in FIG. 8 , by expanding the expansion tape 13 in this way, only the protruding portion 12 a of the adhesive sheet 12 protruding toward the outer peripheral side of the wafer 1 is split. Here, the wafer 1 is not divided, but the expanded tape 13 is expanded to the extent that the protruding portion 12a is divided.

When the protruding part 12a is split, it is preferable to cool at least the protruding part 12a because it is easy to split. For example, the protruding portion 12a can be cooled by spraying a cooling fluid such as cooled air directly from the front side or through the expansion belt 13 on the back side to the protruding portion 12a. Alternatively, a method may be adopted in which the entire expansion device 40 is housed in a cooling chamber, and the temperature of the atmosphere in the cooling chamber is set to, for example, about 0° C. to -30° C. to expand while cooling the whole.

When the protruding portion 12a is split, debris 12b of the adhesive sheet 12 is generated from the protruding portion 12a as shown in FIG. The protective member 11 is pasted on the surface 1 a of the wafer 1 .

(6) Protective parts removal procedure

Next, as shown in FIG. 9 , the protective member 11 disposed on the surface 1 a of the wafer 1 is removed. Fragments 12b of the adhesive sheet 12 generated and scattered when the adhesive sheet 12 was split adhered to the surface of the removed protective member 11, and the surface 1a of the wafer 1 from which the protective member 11 was removed was in a clean state.

(7) Second expansion step

Next, as shown in FIG. 10 , the expansion band 13 is expanded again by the expansion device 40 . Thereby, the wafer 1 is divided along the planned dividing line from the above-mentioned reformed layer 1c, which is the starting point of dividing, and the adhesive sheet 12 corresponding to the device 2 is broken along the planned dividing line, and the wafer 1 is separated into pieces as shown in FIG. 11 . It becomes a chip 3 with an adhesive sheet 12 having the device 2 on the surface.

(8) Ring frame pasting steps

Next, in a state where the intervals between individual chips 3 formed by dividing the wafer 1 are maintained, as shown in FIG. surface side. The annular frame 14 is a frame whose inner circumference is larger than the outer circumference of the adhesive sheet 12 and has a size capable of being arranged inside the clamp member 41 , and is formed of a rigid metal plate such as stainless steel. The annular frame 14 is attached to the extension tape 13 so as to be concentric with the wafer 1 , and the plurality of chips 3 formed by dividing the wafer 1 are accommodated in the opening 14 a of the annular frame 14 .

Then, as shown in FIG. 12( b ), the portion to which the expansion tape 13 is pasted on the back side of the ring frame 14 is cut by the cutting machine 50 . Thereby, the structure shown in FIG. 13 in which a plurality of chips 3 with adhesive sheets 12 are attached to the center of the extension tape 13 with the ring-shaped frame 14 attached to the outer periphery is carried out from the extension device 40 . The chip 3 is processed by using the ring frame 14 and transferred to the next process (for example, a pick-up process of picking up the chip 3 with the adhesive sheet 12 from the expansion tape 13 ).

(9) Action and effect of one embodiment

In the processing method of one embodiment as described above, the first expansion step is completed in the state where the protective member 11 is arranged on the surface 1a of the wafer 1, and at this point, the outer peripheral side of the adhesive sheet 12 toward the wafer 1 is The protruding protruding portion 12a is split. And debris 12 b of the adhesive sheet 12 generated at the time of splitting adheres to the protective member 11 . After the first expansion step is performed, since the protective member 11 to which the debris 12b is attached is removed from the wafer 1, the debris 12b can be completely prevented from adhering to the surface 1a of the wafer 1.

In this embodiment, after the second expansion step is performed to divide the wafer 1 into a plurality of chips 3 , the annular frame 14 is attached to the expanded area while maintaining the intervals between the divided chips 3 . belt 13. As a result, the expanded tape 13 is held by the ring frame 14 in an expanded state, and the intervals between the divided chips 3 are maintained. Therefore, by handling the ring frame 14 , it is possible to carry out conveyance and the like without damaging the chips 3 .

In addition, the protective member 11 is a protective member that prevents the debris 12b of the adhesive sheet 12 from adhering to the wafer surface. Afterwards, in the processing before removing the protective member 11, there is such an advantage that the protective member 11 can be flexibly used as a protective device 2 by preventing the holding table 21, 31 from directly contacting the surface 1a by the protective member 11, for example. protection parts.

(10) Other implementation modes

FIG. 14 shows how the extension band 13 is expanded using an extension device 60 different from the above. That is, the above-mentioned first expansion step and second expansion step can also be performed by this expansion device 60 .

At this time, the expansion device 60 is configured as follows: around the cylindrical workbench 61, an elevating workbench 63 that can be raised and lowered by the air cylinder device 62 is arranged, and the above-mentioned annular frame 14 is pasted on the adhesive sheet 12 in advance. The wafer 1 is placed in a state where the extension tape 13 of the wafer 1 is pasted. Inside the table 31 is provided a nozzle 64 that sprays cooling fluid to the expansion belt 13 .

Regarding the expansion of the wafer 1, first, as shown in (a) of FIG. On the end face, the ring frame 14 is loaded on the lifting table 63 . Next, the ring frame 14 is fixed to the elevating table 63 by the clamp device 65 provided on the elevating table 63 .

And, as shown in FIG. 14( b ), in a state where the adhesive sheet 12 is cooled by spraying cooling fluid from the nozzle 64 , the following first expansion step is performed: shrinking the air cylinder device 62 to split the adhesive sheet 12 . Protruding portion 12a of sheet 12. When the elevating table 63 descends, the expansion belt 13 expands outward, and the protruding portion 12 a of the adhesive sheet 12 is split.

Next, after removing the protective member 11 from the surface of the wafer 1, as shown in (c) of FIG. Split into chips3.

The first expansion step and the second expansion step can also be performed by the expansion device 60 in this way. Since the protective member 11 is pasted on the surface 1a of the wafer 1 in the first expansion step, debris 12b of the protruding portion 12a of the adhesive sheet 12 generated in the first expansion step does not adhere to the surface 1a of the wafer 1 .

In addition, in the above-mentioned embodiment, the division starting point formed along the planned division line of the wafer 1 is formed by the modified layer 1c formed by irradiation of the laser beam, but the division starting point may be formed on the surface 1a of the wafer 1, for example. The grooves on the side include cutting grooves formed by a cutting tool, laser processing grooves formed by irradiating a laser beam having an absorbing wavelength to the wafer 1, and the like.

In addition, the order of the backside grinding of the wafer 1 and the formation of the origin of division is arbitrary, and contrary to the above-described embodiment, the backside grinding of the wafer 1 may be performed after the formation of the origin of division.

Claims (2)

1. a kind of processing method, it is guard block to be equipped with surface and along segmentation preset lines formed with the plate for splitting starting point The processing method of shape thing,

Above-mentioned processing method is characterised by having：

Gluing steps, plate object is matched somebody with somebody through the diameter adhesive sheet bigger than plate object and is set in expansion bands；

First expansion step, after above-mentioned gluing steps are implemented, the shape on the surface of plate object is disposed in above-mentioned guard block Above-mentioned expansion bands are expanded under state, so as to entering line splitting to the above-mentioned adhesive sheet that the outer circumferential side of plate object is leant out；

Guard block removing step, after above-mentioned first expansion step is implemented, remove the above-mentioned guarantor for being disposed in plate object surface Protect part；And

Second expansion step, after above-mentioned guard block removing step is implemented, above-mentioned expansion bands are expanded, from above-mentioned segmentation starting point Split plate object along above-mentioned segmentation preset lines, and it is corresponding with plate object above-mentioned viscous along the predetermined thread breakage of above-mentioned segmentation Contact pin.

2. processing method according to claim 1, it is characterised in that

Above-mentioned processing method has ring-shaped frame gluing steps, in the ring-shaped frame gluing steps, is implementing above-mentioned second After expansion step, in the state of the interval between the chip one by one for maintaining segmentation plate object and being formed, by ring-shaped frame Above-mentioned expansion bands are pasted, form the opening that the multiple said chips split plate object and formed are accommodated in above-mentioned ring-shaped frame Mode.