JPH09115863A - Method and apparatus for adhering surface protective tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely peel a surface protective tape adhered to a semiconductor element forming face of a wafer, cut along the shape of the wafer, and pasted to a peel tape after polishing the back face of the wafer in the wafer back face polishing step, without exerting any excessive force on the wafer. SOLUTION: According to the polishing method and apparatus, in a back face polishing step of a wafer 1, a surface protective tape 3 having an adhesive face is laid on a semiconductor element forming face 2 on the front face of the wafer 1, pressed to adhere and cut along the shape of the wafer to prepare for polishing the back face of the wafer. In this case, the tape 3 is cut so that a part or entire thereof may remain as an extruded region 10 at the outside of the wafer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for applying a surface protection tape in the step of grinding the back surface of a wafer on which semiconductor elements are formed.

[0002]

2. Description of the Related Art FIG. 5 is a flowchart of a conventional wafer back surface grinding process. In the figure, reference numeral 1 denotes a wafer having a semiconductor element formed on one surface thereof, and a case of using an orientation flat wafer will be described here. (A) of this figure
As shown in, on the semiconductor element formation surface 2 of the wafer 1,
For example, the surface protection tape 3 made of polyester or the like and coated with water-soluble glue on one side is placed, and is pressed and adhered by a roller or the like not shown.

Then, as shown in FIG. 5B, the circumferential portion of the wafer 1 is cut while the circumferential cutter 4 is in contact with the end of the wafer 1. After that, the orientation flat portion is similarly brought into contact with the edge of the wafer 1 by the straight line cutter 5 and cut, whereby the surface protection tape 6 having the same size as the wafer 1 can be left on the wafer 1. This state is shown in FIG.

Next, the back side 7 of the wafer 1 is polished by an apparatus such as a back grinder, and as shown in FIG.
A wafer 8 having a predetermined thickness of 200 μm to 400 μm is formed. Then, in the tape peeling device, with the wafer 8 fixed with a vacuum chuck,
A peeling tape 9 for peeling off the surface protection tape 6 is adhered, the peeling tape 9 is peeled off, the wafer is washed with pure water or an organic solvent and dried to complete the back surface grinding step.

[0005]

However, in the above-mentioned conventional technique, there are many troubles in which the surface protection tape cannot be peeled off in the surface protection tape peeling step after the back surface of the wafer is ground. That is, as shown in (e) of FIG. 5, even if the peeling tape is pulled up, the surface protection tape is not peeled off from the wafer, or the protection tape is torn and peeled off only in the width of the peeling tape.

The peeling tape can be peeled off by changing the specification of the peeling tape and using a tape containing fibers and having a strong adhesive force. However, the price of the peeling tape is high (for example, about 5 times) and added to the wafer. Since the force becomes large, the vacuum degree of the vacuum chuck for fixing the wafer in the tape peeling device has to be raised, and there is a problem that the element characteristics are deteriorated due to the stress applied to the wafer. Also,
In order to secure a higher degree of vacuum than that normally used in factories and the like, it is necessary to prepare equipment dedicated to this process, which causes a problem of increasing utility cost.

[0007]

According to the present invention, a surface protection tape having an adhesive surface is placed on a semiconductor element forming surface on the front surface side of a wafer and affixed under pressure during a back surface grinding step of a wafer. In preparation for polishing the back surface of the wafer by cutting the surface protection tape in accordance with the shape of the wafer, and in the apparatus for bonding the surface protection tape, when the surface protection tape is cut off, part or all of this surface protection tape is placed outside the wafer. It is characterized in that it is cut out so as to remain as a protruding area.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a flowchart of a wafer back surface grinding process according to the present embodiment. In this figure, 1 indicates a wafer having a semiconductor element formed on one surface. In the present embodiment, as an example of the wafer, the case where an orientation flat wafer including a circumferential portion and an orientation flat portion is used is described. As shown in (a) of this figure, a semiconductor element forming surface 2 of the wafer 1 is provided with a surface protection tape 3 made of, for example, polyester or the like and a water-soluble adhesive applied to one surface thereof, and a wafer (not shown) or the like is used for the wafer Adhere to the surface.

Then, as shown in FIG. 1B, the circumferential portion of the wafer 1 is cut while the circumferential cutter 4 is in contact with the end of the wafer 1. After that, cut the surface protection tape of the orientation flat part with the straight line cutter 12,
At this time, move the cutter from the wafer edge to, for example, 0.2 to
The surface protection tape 11 is left on the wafer 1 so as to have a protruding region 10 which is a region protruding from the end of the wafer by cutting the wafer 1 about 0.7 mm apart. This state is shown in FIG.

If the protrusion area 10 is too large, the tape may roll up on the ground surface side during back grinding and become entangled with the grinding wheel, which may cause problems such as wafer cracking and wheel deterioration. The protruding region 10 may be formed to the extent of the range. Next, as shown in FIG. 1D, the back surface 7 of the wafer 1 is polished by an apparatus such as a back grinder to, for example, 200 μm to 40 μm.
A wafer 8 having a predetermined thickness of 0 μm is formed.

Thereafter, while the wafer 8 is fixed by a vacuum chuck with a tape peeling device, a peeling tape 9 is adhered onto the surface protection tape 11 and peeled from the orientation flat portion side as shown in FIG. 1 (e). The tape 9 is pulled up in the drawing to peel the surface protection tape 11 from the wafer 8. At this time, since the protruding area 10 in the orientation flat portion of the protective tape is not adhered to the wafer 8, the peeling is started from that portion, and the surface protective tape 11 can be peeled with a light force over the entire wafer 8. it can.

The wafer 8 thus treated is washed with pure water or an organic solvent and dried to complete the back surface grinding step. As an example of a device for executing the above-described steps, the surface protection tape sticking device of the present embodiment will be described below. 2A and 2B are explanatory views of the surface protection tape sticking apparatus of the present embodiment, in which FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is an operation explanatory view of a tape cutter. ing.

First, the structure of the surface protection tape sticking apparatus will be described with reference to FIGS. 2 (a) and 2 (b). Reference numeral 13 is a loader wafer carrier, and 14 is a wafer before processing. Reference numeral 15 is an unloader carrier, and 16 is a processed wafer. Reference numeral 17 is a wafer transfer robot. Reference numeral 18 denotes a chuck table which is a fixing means for fixing the wafer, and 19 is a wafer on the chuck table. Reference numeral 4 denotes a cutter for cutting the circumference, and 12 denotes a cutter for a straight line for the orientation flat portion.

Reference numeral 20 denotes a roll of surface protection tape before treatment,
21 is a surface protection tape pulled out from the roll, 2
2 is the base tape peeled from the surface protection tape, 23
Is a roller which is a pressure contact means for adhering the tape to the wafer, and 24 is a roll of the tape after cutting. The apparatus of the present embodiment is characterized in that the position of the straight line cutter 12 that cuts the tape in the straight line portion of the orientation flat portion can be freely set.

The operation of the above apparatus will be described below. First, one unprocessed wafer 14 is taken out by the robot 17 from the wafer carrier 13 on the loader side, set on the chuck table 18 with the surface of the wafer facing upward, and the orientation flat portion is located on the right side of the drawing.
The wafer is fixed by a vacuum chuck or the like (shown as wafer 19).

The base tape 22 is peeled off from the surface protection tape 21 pulled out from the roll 20 of the surface protection tape, the adhesive surface of the surface protection tape 21 which is an adhesive surface is exposed and placed on the wafer 19, and the roller 23 is used. Then, it is adhered to the wafer 19. After that, the tape in the circumferential region of the wafer 19 is cut along the edge of the wafer 19 by the circumferential cutter 4. Next, the tape of the orientation flat portion is cut by the straight line cutter 12, but as shown in (c) of FIG. 2, by utilizing the fact that the mounting position of the straight line cutter 12 can be moved left and right in the figure, The tape of the orientation flat portion is cut so as to protrude from the wafer 19 by, for example, about 0.4 mm.

Then, the wafer to which the surface protection tape is attached is taken out from the chuck table 18 by the transfer robot 17 and stored in the unloader carrier 15. The surface protection tape having a hole cut into a wafer shape is wound as a roll 24. As described above, when the protective tape is cut along the periphery of the wafer with the cutter, the protruding position 10 is formed by slightly shifting the cutting position of the orientation flat portion, so that the surface after backside grinding can be performed without adding steps. The protective tape can be peeled easily and surely.

Second Embodiment This embodiment relates to the case where a notch wafer having no orientation flat portion is used as an example of the wafer. FIG. 3 shows a flow chart of the wafer backside grinding process of this embodiment. In this figure, reference numeral 25 denotes a notch wafer having a surface on which a semiconductor element is formed. As shown in (a) of this figure, the element forming surface 2 of the wafer 25
Then, a surface protection tape 3 made of, for example, polyester or the like and having a water-soluble adhesive applied to one surface thereof is placed and adhered to the wafer surface by a roller or the like not shown.

Then, as shown in FIG. 3B, the surface protection tape 3 on the entire peripheral portion of the wafer 25 is cut by the peripheral cutter 26. For example, about 70% to 80% of the peripheral portion is conventional. Similarly, as shown on the left side of the figure, the surface protection tape on the wafer 25 is made the same as the wafer by cutting the blade surface of the circumferential cutter 26 along the wafer end face by vertically or slightly inclining it toward the inside of the wafer. Cut so that the shape is the same size or slightly inside.

After that, as for the remaining circumferential portion, as shown on the right side of the drawing, the blade surface of the circumferential cutter 26 is placed on the wafer 2.
5 is moved along the wafer edge while being tilted to the outside of the wafer 5, so that the surface protection tape 28 has a protrusion area 27 that is an area protruding from the wafer edge.
Try to leave it at 5. This state is shown in FIG.

The protruding area 27 is set to be necessary and sufficient for smooth separation (for example, about 0.2 to 0.7 mm) to protrude from the wafer, and the area 27 is longer than the width of the peeling tape 9. You should keep it. Next, as shown in FIG. 3D, the back surface 29 of the wafer 25 is polished by a device such as a back grinder, and is polished to, for example, 200 μm or more.
A wafer 30 having a predetermined thickness of 400 μm is formed.

Thereafter, while the wafer 30 is fixed by the vacuum chuck with the tape peeling device, the peeling tape 9 is adhered onto the surface protection tape 28, and as shown in FIG.
The peeling tape 9 is pulled up from the protruding area 27 side in the drawing to peel the surface protection tape 28 from the wafer 30. At this time, since the protruding area 27 of the surface protection tape 28 is not adhered to the wafer 30, peeling is started from that portion, and the surface protection tape 28 can be peeled off with a light force over the entire wafer 30.

The wafer 30 thus treated is washed with pure water or an organic solvent and dried to complete the back surface grinding step. As an example of a device for executing the above-described steps, the surface protection tape sticking device of the present embodiment will be described below. 4A and 4B are explanatory views of the surface protection tape sticking apparatus according to the present embodiment. FIG. 4A is a plan view, FIG. 4B is a front view, and FIG. 4C is an operation explanatory view of a tape cutter. ing.

First, the structure of the surface protection tape sticking device will be described with reference to FIGS. 4 (a) and 4 (b). Reference numeral 13 is a loader wafer carrier, and 31 is a wafer before processing. Further, 15 is an unloader carrier, and 32 is a processed wafer. Reference numeral 17 is a wafer transfer robot. Reference numeral 18 denotes a chuck table which is a fixing means for fixing the wafer, and 33 is a wafer on the chuck table.

Reference numeral 26 is a circumferential cutter for cutting the circumferential portion, and the angle can be changed depending on the cutting position. Reference numeral 20 is a roll of surface protection tape before treatment, 21 is a surface protection tape pulled out from the roll, 22 is a base tape peeled from the surface protection tape, and 23 is a roller which is a pressure-bonding means for adhering the surface protection tape to a wafer. , 24 are rolls of the surface protection tape after cutting.

The apparatus according to the present embodiment has a cutter 2 for the circumference.
The feature is that the angle of 6 can be freely changed. The operation of the above device will be described below.
First, one unprocessed wafer 31 is taken out by the robot 17 from the wafer carrier 13 on the loader side, set on the chuck table 18 with the surface of the wafer facing up, and then fixed by a vacuum chuck or the like (wafer 33 It is shown as.). At this time, the position of the notch is free, but here it is on the right side of the drawing.

The base tape 22 is peeled from the tape 21 pulled out from the roll 20 of the surface protection tape, and the adhesive surface, which is the adhesive surface of the tape 21, is exposed to expose the wafer 33.
And then adhere it to the wafer 33 with the roller 23. After that, as shown in FIG. 4C, the tape in the circumferential region of the wafer 33 is removed by the circumferential cutter 26.
Cut along the edge of 3, but at this time, for example, 1/4 of the circumference
With respect to the ⅕ region, the protruding region 27, which is a portion protruding from the wafer 33, can be formed by inclining the cutter 26 largely outward.

In the protruding area 27, the inclination angle of the cutter is set so that the tape protrudes, for example, about 0.4 mm. Further, although the inclination angle of the cutter is variable in the present embodiment, when the inclination angle is fixed and the protruding area is always formed,
An apparatus for forming a protruding area over the entire circumference of the wafer is obtained.

Then, the wafer to which the surface protection tape is attached is taken out from the chuck table 18 by the transfer robot 17 and stored in the unloader carrier 15. The perforated tape cut into a wafer shape is wound up as a roll 24. As described above, when the surface protection tape is cut along the periphery of the wafer with the cutter, the cutter 26 is tilted at a part of the circumferential portion to form the protrusion area 27 of the surface protection tape, thereby adding a step. Without
It becomes possible to easily and surely peel the surface protection tape after the back surface is ground.

In the first and second embodiments, a circular wafer made of silicon or the like has been described as an example. However, in addition to this, a non-circular wafer made of, for example, a compound semiconductor, the present invention is also applicable. Can be applied.

[0031]

As described above in detail, when the surface protection tape attached to the wafer is cut off, a protruding area is formed in the surface protection tape, so that the back surface grinding can be performed without adding steps. This has the effect that the subsequent surface protection tape peeling can be performed easily and reliably.

Further, it is not necessary to use an expensive stripping tape having a special specification as a stripping tape, and it is a low-priced ordinary stripping tape, which has the effect of reliably stripping the protective tape. further,
When the surface protection tape is peeled off, the protection tape can be reliably peeled off without raising the vacuum degree of the vacuum chuck, so the force applied to the wafer is weakened and the device characteristics are not adversely affected. The vacuum chuck may have a normal vacuum degree, so that the utility cost can be suppressed.

In addition, since the tape peeling process proceeds smoothly, there is an effect that the equipment operating rate is improved and the workability is improved.

[Brief description of the drawings]

FIG. 1 is a flowchart of a wafer back surface grinding process according to the first embodiment.

FIG. 2 is an explanatory view of the surface protection tape sticking device according to the first embodiment.

FIG. 3 is a flowchart of a wafer back surface grinding process according to the second embodiment.

FIG. 4 is an explanatory diagram of a surface protection tape sticking device according to a second embodiment.

FIG. 5 is a flowchart of a conventional wafer backside grinding process.

[Explanation of symbols]

 1 Wafer 2 Semiconductor Element Forming Surface 3 Surface Protecting Tape 8 Wafer 9 Peeling Tape 10 Overhanging Area 11 Surface Protecting Tape 12 Straight Line Cutter 18 Fixing Means 19 Wafer 21 Surface Protecting Tape 23 Pressing Means 25 Wafer 26 Circular Cutter 27 Overhanging Area 28 Surface protection tape 30 wafer 33 wafer

Claims (6)

[Claims] 1. A wafer, which has a semiconductor element forming surface on the front surface side, is subjected to a back surface grinding process by placing a surface protection tape having an adhesive surface on the semiconductor element forming surface of the wafer, and applying pressure to the wafer. In the method of attaching the surface protection tape to prepare for polishing the back surface of the wafer by cutting the surface protection tape in accordance with the shape of the above, when cutting the surface protection tape, a part or all of the surface protection tape is formed as an area protruding outside the wafer. A method for applying a surface protection tape, which is characterized by cutting so that it remains. 2. The surface protection tape affixed to an orientation flat wafer according to claim 1, wherein the circumference of the surface protection tape is cut along the edge of the wafer so that the surface protection tape has the same size as the wafer. A little smaller so that it remains on the wafer, and at the orientation flat part, cut the surface protection tape outside the edge of the wafer and cut it so as to form a protruding area. Method. 3. The surface protection tape attachment according to claim 1, wherein the surface protection tape attached to the notch wafer is cut out so as to form a protruding region on a part or all of the circumference of the wafer edge. Method. 4. A fixing means for fixing a wafer having a semiconductor element forming surface on the front side, a pressure contact means for pressing and adhering a surface protection tape having an adhesive surface on the wafer, to the wafer, In a surface protection tape sticking device having a cutter that cuts the surface protection tape adhered to the semiconductor element formation surface according to the shape of the wafer, in order for the cutter to leave the protruding area of the surface protection tape outside the shape of the wafer A surface protection tape sticking device, characterized in that the surface protection tape can be cut off when moved. 5. The surface protection tape adhered to an orientation flat wafer according to claim 4, wherein the surface protection tape is cut along the edge of the wafer at the circumference thereof, and the surface protection tape has the same size as the wafer, or A cutter for the circumference that makes it slightly smaller and remains on the wafer, and a cutter for the straight that cuts the surface protection tape outside the edge of the wafer at the orientation flat portion to form a protruding area. A surface protection tape sticking device, which is provided with. 6. The notch wafer and the cutter according to claim 4, wherein the surface protection tape attached to the notch wafer can be cut so as to form a protruding region on a part or the whole of the circumference of the wafer end. The surface protection tape sticking device is characterized in that the angle with the blade surface of the is variable.