TW201616567A - Method and apparatus for separating adhesive tape - Google Patents

Abstract

The object of the present invention is to precisely detect abnormal portions, such as cracks or damages, on a semiconductor wafer after polishing its back. The periphery of the wafer is held by an annular protruding part provided on a holding table, and gas is supplied and pressurized in a space of the holding table sealed by the wafer. Under the pressurized condition, a separating component is used to attach a separating tape onto a protective tape and integrally separate the protective tape from the wafer in a manner of folding back while separating the separating tape. In the separating process, a pressure meter is used to detect the variation of pressure in the space of the holding table. A measured value of the detected pressure is compared with a predetermined reference value in order to determine the cracks on the wafer.

Description

Adhesive tape stripping method and adhesive tape stripping device

The present invention relates to an adhesive tape peeling method and an adhesive tape peeling method for peeling off an adhesive tape such as a protective tape or a double-sided adhesive tape which is attached to a circuit formation surface of a semiconductor wafer (hereinafter, referred to as "wafer" as appropriate) Device.

After the protective tape is attached to the surface of the wafer on which the pattern forming process has been completed, a back surface polishing process in which the entire back surface is uniform is applied. The protective tape is peeled off from the surface before the wafer with the protective tape is transferred to the cutting process for fine-cut separation into wafers.

Regarding the method of peeling the protective tape from the surface of the wafer, for example, it is carried out as follows. The surface to which the protective tape is attached is faced upward and the wafer is adsorbed and held on the holding table. The adhesive tape for peeling is attached to the protective tape while rotating the attaching roller. Thereafter, the adhesive tape is gradually reversed and peeled off by a plate-like edge member having a thinner tip end, whereby the protective tape attached to the adhesive tape is integrally peeled off from the wafer surface (see Patent Document 1).

Prior technical literature Patent Document 1

JP-A-2002-124494

However, the above conventional methods have the following problems.

In recent years, in order to enable high-density packaging in response to rapid development of applications, wafers have been required to be thinned. Further, the size of the wafer tends to increase while the thickness is reduced. Since the rigidity of the wafer is reduced in accordance with such thinning and enlargement, wafer cracks are likely to occur.

The case where cracks are formed can be detected by a change in the attractive force of a plurality of adsorption holes formed in the holding stage. However, the change in the attractive force can be detected only in the case where the portion where the crack is generated overlaps with the adsorption hole. That is, the occurrence of cracks on the entire wafer cannot be detected.

Therefore, when the wafer in which the crack state has occurred is continuously processed, there is a problem that the debris is caught in the device to cause an unnecessary stop, or contaminate the wafer of the next processing object.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an adhesive tape peeling method and an adhesive tape peeling apparatus which can accurately detect cracks and the like generated in a semiconductor wafer which has been subjected to back grinding.

The present invention has the following constitution for achieving such a purpose.

That is, an adhesive tape peeling method is an adhesive tape peeling method of peeling off an adhesive tape attached to a semiconductor wafer, and is characterized in that: a holding process is performed to hold the semiconductor wafer in an annular convex portion provided in the holding stage Peripheral; pressurization process, by the aforementioned semiconductor wafer The hollow interior of the sealed holding chamber supplies gas and pressurizes; in the peeling process, the peeling tape is attached to the adhesive tape by the peeling member, and the peeling tape is peeled off while peeling off, and the adhesive tape is integrally peeled off from the semiconductor wafer; a process of detecting, by the detector, at least one of a change in a supply flow rate or a pressure of a gas toward a hollow interior of the holding stage in the stripping process; and a discriminating process of comparing the detected measured value with a predetermined reference value To identify cracks in semiconductor wafers.

According to the above method, since the adhesive tape covering the surface is peeled off, the gas leaks from the crack portion of the wafer. At least one of the supply flow rate of the gas that changes due to the leak and the pressure change inside the hollow is detected by the detector, whereby the crack can be detected. Therefore, it is possible to prevent wafers that are cracked from being moved to the next project. Further, in the case where cracks are detected, the fragments of the wafer can be quickly removed or the cracks can be treated. Therefore, it is possible to avoid contamination of the wafer of the holding stage or the next processing object. Further, the term "crack" in the present invention means an abnormal portion including "crack" and "breakage".

Further, with respect to the above method, the position at the time point at which the crack is detected can also be memorized.

According to this method, the position of the crack can be quickly confirmed and treated. Also, the location information can be utilized in the next project. For example, during the dicing process, the cracked portion of the wafer can be discarded or removed from the wafer that has been finely separated.

The present invention has the following constitution for achieving such a purpose.

That is, an adhesive tape peeling device is an adhesive tape peeling device that peels off an adhesive tape attached to a semiconductor wafer, and is characterized in that a holding stage for holding an outer circumference of the semiconductor wafer by an annular convex portion; a pressurizing device for supplying a gas to the hollow interior sealed by the semiconductor wafer; and a peeling tape supply mechanism toward the semiconductor crystal A strip-shaped peeling tape is supplied to the strip; the peeling means attaches the peeling tape to the semiconductor wafer on the holding stage by the peeling member, and then passes through the peeling member to fold back and peel off the peeling tape, thereby integrally bonding the adhesive tape from the semiconductor Wafer peeling; the horizontal driving mechanism relatively moves horizontally in such a manner that the holding table and the peeling member cross each other; the control portion adjusts the pressure of the hollow interior of the holding table; and the detector detects the peeling of the adhesive tape At least one of a change in the supply flow rate of the gas and a change in the pressure inside the hollow; the determining unit discriminates the crack of the semiconductor wafer from a comparison between the measured value detected by the detector and a predetermined reference value; The recycling mechanism winds up the release tape integrated with the aforementioned protective tape.

According to this configuration, at least one of the gas flow rate and the pressure change toward the hollow interior which is changed by peeling off the adhesive tape covering the surface of the wafer is detected. Therefore, cracks generated in the wafer can be detected by the change. That is, the above method can be suitably carried out.

Further, in this configuration, the memory unit may be provided to store the position of the crack determined by the determination unit.

According to this configuration, the crack portion can be quickly confirmed from the stored position information. Moreover, the location information can also be utilized in projects such as cutting works and the like.

According to the adhesive tape peeling method and the adhesive tape peeling device of the present invention, cracks generated in the semiconductor wafer after the back grinding can be accurately detected.

1‧‧‧ Keeping the table

2‧‧‧With the supply department

3‧‧‧ peeling mechanism

4‧‧‧With recycling department

6‧‧‧ annular convex

7‧‧‧Adsorption ditch

8‧‧‧vacuum source

11‧‧‧Flow

12‧‧‧Air supply unit

13‧‧‧ Pressure gauge

20‧‧‧ peeling unit

29‧‧‧Exfoliation members

36‧‧‧Control Department

37‧‧‧Discrimination Department

PT‧‧‧protective tape

Ts‧‧‧ peeling tape

W‧‧‧Semiconductor Wafer

1 is a partially broken perspective view of a semiconductor wafer.

2 is a perspective view of the back side of the semiconductor wafer.

3 is a partial longitudinal cross-sectional view of a semiconductor wafer.

Figure 4 is a front view of the protective tape stripping device.

Fig. 5 is a plan view showing a schematic configuration of a main part of a protective tape peeling device.

Fig. 6 is a longitudinal sectional view of the holding table.

Fig. 7 is a view showing the peeling action of the protective tape.

Fig. 8 is a view showing the peeling action of the protective tape.

Fig. 9 is a view showing the peeling action of the protective tape.

Fig. 10 is a view showing the peeling action of the protective tape.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Further, in the present embodiment, the protective tape peeling device is taken as an example of the adhesive tape peeling device. In the present embodiment, the protective tape is peeled off from a semiconductor wafer (hereinafter, referred to as "wafer" as appropriate) in which a reinforcing portion is formed on the outer periphery of the back surface by an annular convex portion.

<wafer>

As shown in FIGS. 1 to 3, the wafer W is a wafer subjected to back-grinding treatment in a state in which a protective tape PT is attached to a surface on which a pattern is formed and the surface is protected. Grinding (back grinding) is performed in such a manner that the outer peripheral portion of the back surface portion retains about 2 mm in the radial direction. In other words, a wafer having a flat concave portion b formed on the back surface and having a shape in which the annular convex portion r remains along the outer periphery thereof is used. For example, the depth d processed into the flat concave portion b is several hundred μm, and the wafer thickness t of the grinding region is several tens of μm. Therefore, the annular convex portion r formed on the outer periphery of the back surface acts as an annular rib that increases the rigidity of the wafer W, and suppresses the deflection of the wafer W during transportation or other processing.

<Protection tape peeling device>

4 is a front view showing an overall configuration of a protective tape peeling device according to an embodiment of the present invention; FIG. 5 is a plan view showing a schematic configuration of a main part of the protective tape peeling device; and FIG. 6 is a schematic view showing a configuration of the holding table. Longitudinal section. Further, the protective tape peeling device of the present embodiment corresponds to the adhesive tape peeling device of the present invention.

As shown in FIG. 4, the protective tape peeling device is composed of a holding table 1, a tape supply unit 2, a peeling mechanism 3, and a tape collecting unit 4.

As shown in FIGS. 4 to 6, the holding stage 1 is provided with a recess 5 whose diameter is formed to be close to the diameter of the grinding area of the back surface of the wafer W. A plurality of adsorption grooves 7 acting on the annular convex portion r of the wafer W are formed on the surface of the annular convex portion 6 on the outer peripheral portion of the concave portion 5. The adsorption groove 7 is connected to the external vacuum source 8 in series.

Further, a plurality of air supply holes 10 are formed to pressurize the space 9 formed by the flat concave portion b of the wafer W and the concave portion 5 of the holding table 1. The air supply hole 10 is connected to the air supply device 12 disposed outside the flow path 11 . Further, the flow path 11 is provided with a pressure gauge 13 for detecting a pressure change of the space 9. Further, a needle valve for pressure control that communicates the space 9 with the outside is provided on the side wall of the annular convex portion 6. Further, the air supply device 12 corresponds to the pressurizer of the present invention, and the pressure gauge 13 corresponds to the detector of the present invention.

Further, as shown in FIG. 4, the holding table 1 is supported by a movable table 15 which is supported so as to be slidable forward and backward by a pair of right and left rails 14 which are horizontally arranged along the front and rear. Then, the movable table 15 is driven by screw feed through the screw 17 that is driven forward and reverse by the pulse motor 16.

The tape supply unit 2 guides the peeling tape Ts which is led out from the raw material roll to the peeling unit 20 which will be described later.

The peeling mechanism 3 is provided with the peeling unit 20. A support frame 22 composed of an aluminum drawn material is fixed over a range of a pair of left and right longitudinal frames 21 which are erected on the apparatus base. A box-shaped base 23 is coupled to the left and right central portions of the support frame 22. Further, the elevating table 25 that is slidably supported by the pair of right and left longitudinal rails 24 provided on the base 23 is moved up and down through the ball shaft that is driven and connected by the motor 26. The peeling unit 20 is equipped on the lifting table 25.

The lifting platform 25 is formed in a hollow frame shape that penetrates vertically. The peeling unit 20 is provided on the inner lower portion of the side plate 27 provided on the right and left sides of the lift table 25. The support frame 28 is fixed in the range of the side plates 27. A peeling member 29 is attached to the center of the support frame 28.

The peeling member 29 is formed in a plate shape shorter than the diameter of the wafer W, and is formed in a tapered shape that is thinner toward the tip end. The peeling member 29 is fixed in a posture inclined obliquely downward.

Further, the supply guide roller 31 of the peeling mechanism 3 is pivotally supported at the rear of the side plate 27 so as to be freely idly rotatable. Further, a plurality of guide rollers 32 for collecting, a nip roller 33, and a tension roller 34 are provided above the peeling unit 20.

The guide roller 32 for recovery is pivotally supported to be freely idling. The tension roller 34 is rotatably provided to the support arm 35, and is provided to be swingable via the support arm 35. Therefore, the tension roller 34 imparts a moderate tension to the peeling tape Ts that is guided back.

The guide roller 32 and the tension roller 34 for recovery are configured to have a wide roll having a length larger than the diameter of the wafer W, and the outer peripheral surface thereof is a difficult contact surface to which the fluororesin is applied.

The supply guide roller 31 is constructed as a narrow roll that is longer than the width of the release tape Ts and shorter than the diameter of the wafer W.

The tape collection unit 4 winds up and collects the peeling tape Ts sent from the peeling unit 20.

Next, a looping operation of the apparatus of the above embodiment will be described with reference to Figs. 7 to 9.

By the transport robot (not shown), the wafer W to which the back surface is adhered and adhered to the protective tape PT is superposed on the annular convex portion 6 of the holding table 1 by the annular convex portion on the wafer back surface. Placed.

When the wafer 1 is placed on the holding stage 1, the annular convex portion r of the wafer W is adsorbed by the adsorption groove 7 formed in the annular convex portion 6. hold. Thereafter, the air supply device 12 is actuated to start supplying air to the space 9 of the holding table 1 sealed by the wafer W. At this time, as shown in FIG. 7, the space 9 is pressurized until the surface of the wafer W slightly protrudes upward.

When the space 9 reaches a predetermined pressure, the holding table 1 that adsorbs and holds the wafer W moves from the standby position toward the attachment start position of the peeling tape Ts. Next, the motor 26 is actuated to lower the stripping unit 20 to a predetermined height. That is, as shown in FIG. 8, the peeling tape Ts wound around the peeling member 29 is pressed against the end of the protective tape PT on the wafer W, and is attached.

Thereafter, the holding station 1 moves forward. At this time, the peeling tape Ts is attached to the protective tape PT while being pressed by the peeling member 29 while returning the upward bending of the wafer W to be flat. At the same time, the protective tape PT is gradually peeled off from the surface of the wafer W while the peeling tape Ts is folded back by the peeling member 29. In addition, the peeling tape Ts is discharged from the tape supply unit 2 in synchronization with the peeling operation, and the tape retracting unit 4 gradually winds up the peeling tape Ts of the protective tape PT after the adhesive tape is used.

In the peeling process of the protective tape PT, the supply amount of the air from the air supply device 12 is kept constant by the control unit 36, and the pressure of the space 9 is kept constant. That is, the pressure of the space 9 is sequentially monitored by the pressure gauge 13.

However, as shown in FIG. 9, when the protective tape PT is peeled off and the abnormal portion 40 such as cracks or breakage is formed on the wafer W exposed on the surface, air leaks from the abnormal portion to make the space 9 The pressure is reduced. When the pressure gauge 13 detects the change in the pressure drop, the detection signal is transmitted to the control unit 36.

In other words, the control unit 36 determines whether or not the actual measurement value falls within the reference range of the pressure previously stored by the memory device such as the memory. When the measured value is smaller than the predetermined reference range, it is judged that an abnormal portion such as a break or a crack is generated on the wafer W. In the abnormal portion, the position coordinates are obtained from the moving distance from the start position of the peeling tape Ts by the number of pulses of the encoder or the pulse motor 16, and the like. The position coordinates are recorded on the memory device. The position coordinates can be read from the memory device and displayed on a monitor or the like for confirmation.

As shown in FIG. 10, when the protective tape PT is completely peeled off from the surface of the wafer W, the peeling unit 20 is raised and returned to the initial position to prepare for the next process.

Further, the wafer W from which the protective tape PT has been peeled off is moved to the delivery position by the holding table 1.

This completes one cycle of the apparatus of the embodiment, and thereafter repeats the same operation up to a predetermined number of sheets.

According to the apparatus of the above embodiment, since the protective tape PT of the coated surface is peeled off, the gas leaks from the abnormal portion generated on the surface of the wafer W. The pressure gauge 13 detects a pressure change in the space 9 that changes according to the leak, and an abnormal portion can be detected. That is, in the case where an abnormal portion is detected, since the abnormal portion can be specified from the detected position coordinates, a quick treatment can be performed. For example, debris and the like can be quickly removed. Further, the wafer W of the defective product can be removed from the production line. Therefore, unnecessary stopping of the device and the production line can be avoided.

Further, the present invention can also be implemented by the following aspects.

(1) A flow meter can be used in place of the pressure gauge 13 in the above embodiment. In the case where cracks are generated, since the pressure of the space 9 is lowered, the control unit 36 operates the air supply device 12 to increase the flow rate of the air while keeping the pressure of the space 9 constant. Therefore, the generation of cracks can be detected from the change in the flow rate of the air.

In addition, in the embodiment, the pressure gauge and the flow meter can also be used at the same time.

(2) In the above embodiment, the peeling of the peeling tape Ts is attached to the protective tape PT by the lowering of the peeling unit 20, but the peeling unit 20 that does not perform the lifting operation can be moved up and down. Further, a configuration may be adopted in which the holding table 1 is fixed and the peeling unit 20 is moved.

(3) In the above embodiments, even if the abnormal portion is detected, the protective tape PT is completely peeled off from the wafer W. However, the peeling operation may be stopped at the time when the abnormal portion is detected, and the debris or the like may be removed.

(4) In the above-described respective embodiments, for example, a double-sided adhesive tape in which a support plate for reinforcing a stainless steel or a glass substrate having substantially the same shape as the wafer W is peeled off from the wafer W may be used.

(5) The apparatus of the above embodiment may be used by peeling off the protective tape PT or the double-sided adhesive tape attached to the wafer W which has been uniformly ground on the entire back surface.

1‧‧‧ Keeping the table

6‧‧‧ annular convex

7‧‧‧Adsorption ditch

8‧‧‧vacuum source

9‧‧‧ Space

10‧‧‧Air supply hole

11‧‧‧Flow

12‧‧‧Air supply unit

13‧‧‧ Pressure gauge

20‧‧‧ peeling unit

36‧‧‧Control Department

37‧‧‧Discrimination Department

40‧‧‧Abnormal parts

PT‧‧‧protective tape

Ts‧‧‧ peeling tape

W‧‧‧Semiconductor Wafer

Claims (4)

An adhesive tape peeling method for peeling off an adhesive tape attached to an adhesive tape of a semiconductor wafer, characterized by comprising: a holding process for holding an outer circumference of the semiconductor wafer at an annular convex portion of the holding stage; In the pressurizing process, the gas is supplied to the hollow interior of the holding stage sealed by the semiconductor wafer, and the peeling process is performed by attaching the peeling tape to the adhesive tape by the peeling member and peeling off the peeling tape while being folded back. The adhesive tape is integrally peeled off from the semiconductor wafer; during the stripping process, at least one of the change in the supply flow rate or pressure of the gas toward the hollow interior of the holding table is detected by the detector; and the discriminating process is performed from the foregoing detection The measured value is compared with a predetermined reference value to discriminate the crack of the semiconductor wafer. The adhesive tape peeling method of claim 1, wherein in the foregoing detecting process, the position at the time point of detecting the crack is memorized. An adhesive tape peeling device for peeling off an adhesive tape peeling device attached to an adhesive tape of a semiconductor wafer, comprising: a holding stage for holding an outer circumference of the semiconductor wafer by an annular convex portion; and a pressurizing device Supplying a gas to the hollow interior sealed by the semiconductor wafer; The peeling tape supply mechanism supplies a strip-shaped peeling tape to the semiconductor wafer; and the peeling mechanism attaches the peeling tape to the semiconductor wafer on the holding stage by the peeling member, and then passes the peeling tape back by the peeling member Stripping and peeling the adhesive tape integrally from the semiconductor wafer; the horizontal drive mechanism relatively moves horizontally so that the holding stage and the peeling member intersect; the control unit adjusts the pressure inside the hollow interior of the holding stage; the detector In the process of peeling off the adhesive tape, at least one of a change in the supply flow rate of the gas and a change in the pressure inside the hollow is detected; the determination unit compares the measured value detected by the detector with a predetermined reference value. The crack of the semiconductor wafer is discriminated; and the tape recovery mechanism winds and collects the peeling tape integrated with the protective tape. The adhesive tape peeling device of claim 3, further comprising a memory portion for storing a position of the crack determined by the determining portion.