JP2016046436A - Peeling method of pressure-sensitive adhesive tape and peeling device of pressure-sensitive adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect abnormal portions, such as cracking and chipping occurring in a semiconductor wafer after back grinding, accurately.SOLUTION: A protective tape PT is peeled from a semiconductor wafer W integrally, by sticking a peeling tape Ts to the protective tape PT, stuck to the semiconductor wafer W by means of a tabular peeling member 20 tapered toward the tip, and then peeling the peeling tape Ts while folding. In the peeling process, abnormal portions such as cracking and chipping occurring on the surface of the semiconductor wafer W, peeled from the protective tape PT, is detected by means of a detector 11 following the rear of the peeling member 20.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an adhesive tape peeling method and an adhesive tape peeling apparatus for peeling an adhesive tape such as a protective tape or a double-sided adhesive tape attached to a circuit forming surface of a semiconductor wafer (hereinafter referred to as “wafer” as appropriate).

  After a protective tape is applied to the surface of the wafer that has undergone the pattern formation process, the entire back surface is subjected to a back grinding process. The wafer with the protective tape is peeled off from the surface before being transferred to a dicing process in which the wafer is shredded into chips.

  For example, the method of peeling the protective tape from the wafer surface is performed as follows. The wafer is sucked and held on the holding table with the surface to which the protective tape is attached facing upward. Adhere the adhesive tape for peeling onto the protective tape while rolling the application roller. Thereafter, the adhesive tape is reversely peeled off with a tapered plate-like edge member, whereby the protective tape adhered to the adhesive tape is peeled off integrally from the wafer surface (see Patent Document 1).

Japanese Patent Laid-Open No. 2002-124494

  However, the above conventional method has the following problems.

  In recent years, there has been a demand for thinner wafers in order to enable high-density mounting accompanying rapid progress in applications. In addition, the wafer size tends to increase simultaneously with the reduction in thickness. As the thickness and size of the wafer are reduced, the rigidity of the wafer is lowered, so that the wafer is easily cracked.

  When a crack occurs, it can be detected by a change in suction force of a plurality of suction holes formed in the holding table. However, the change in suction force can be detected only when the cracked portion and the suction hole overlap. That is, the occurrence of cracks cannot be detected over the entire surface of the wafer.

  Therefore, if the processing of the wafer in a state where the crack is generated is continued, there is a problem that the fragments are caught in the apparatus and stopped unnecessarily, or the next processing target wafer is contaminated.

  The present invention has been made in view of such circumstances, and provides an adhesive tape peeling method and an adhesive tape peeling device capable of accurately detecting cracks and the like occurring in a semiconductor wafer after back grinding. The main purpose is to do.

  In order to achieve such an object, the present invention has the following configuration.

That is, an adhesive tape peeling method for peeling an adhesive tape attached to a semiconductor wafer,
Including a peeling process in which the adhesive tape is peeled off from the semiconductor wafer by peeling off the peeling tape while the peeling tape is attached to the adhesive tape by a peeling member and folded;
In the peeling process, an inspection process for inspecting cracks in the semiconductor wafer by following the detector from the back of the peeling member;
It is provided with.

  (Operation / Effect) According to the above method, immediately after the pressure-sensitive adhesive tape is peeled off from a wafer that is easily cracked, the detector that follows the peeling member detects the presence or absence of the crack. Therefore, it is possible to prevent the wafer having cracks from being transferred to the next process. In addition, when a crack is detected, the wafer debris can be quickly removed or a measure can be taken against the crack. Therefore, contamination of the holding table and the next wafer to be processed can be avoided. In the present invention, “crack” means an abnormal part including “crack” and “chip”.

  In the above method, the outer periphery of the semiconductor wafer may be held by an annular holding table, and a release tape may be attached to the adhesive tape while peeling by supplying gas to the inside of the hollow of the holding table.

  According to this method, since the wafer thinned with the pressurization is bulged slightly upward in a curved shape, the cracked portion is slightly opened and the gas easily flows out. Therefore, the cracked portion of the wafer can be determined with higher accuracy.

  In order to achieve such an object, the present invention has the following configuration.

That is, an adhesive tape peeling device for peeling an adhesive tape attached to a semiconductor wafer,
A holding table for holding the semiconductor wafer;
A peeling tape supply mechanism for supplying a strip-shaped peeling tape toward the semiconductor wafer;
A peeling mechanism that peels off the peeling tape with the peeling member and peels it off from the semiconductor wafer as a unit after attaching the peeling tape to the semiconductor wafer on the holding table,
A horizontal drive mechanism that relatively horizontally moves so that the holding table and the peeling member intersect,
A detector for detecting cracks in the semiconductor wafer following from the rear of the peeling member;
A tape recovery mechanism for winding and recovering the release tape integrated with the protective tape;
It is provided with.

  (Operation / Effect) According to this configuration, in the process of peeling the adhesive tape from the wafer surface, the crack of the wafer can be detected by the detector that follows from behind the peeling member. That is, the above method can be suitably performed.

In this configuration, the holding table is an annular shape that holds the outer periphery of the semiconductor wafer,
A pressurizer that supplies gas to the internal space of the holding table and pressurizes the semiconductor wafer on the holding table;
A control unit for adjusting the hollow pressure of the holding table;
You may comprise so that it may be provided.

  According to this configuration, since the inside of the holding table is pressurized, the wafer is slightly bulged upwardly in a curved shape. That is, since gas leaks from the cracked portion of the wafer and opens slightly, the cracked portion can be determined with higher accuracy.

  According to the pressure-sensitive adhesive tape peeling method and the pressure-sensitive adhesive tape peeling device of the present invention, it is possible to accurately detect cracks occurring in a semiconductor wafer after back grinding.

It is a front view of a protective tape peeling apparatus. It is a top view which shows schematic structure of the principal part of a protective tape peeling apparatus. It is a front view of a detector. It is a figure which shows peeling operation | movement of a protective tape. It is a figure which shows peeling operation | movement of a protective tape. It is a figure which shows peeling operation | movement of a protective tape. It is a figure which shows peeling operation | movement of a protective tape. It is a partially broken perspective view of the semiconductor wafer used with a modification apparatus. It is a perspective view of the back surface side of the semiconductor wafer used with a modification apparatus. It is a fragmentary longitudinal cross-sectional view of the semiconductor wafer used with a modification apparatus. It is a longitudinal cross-sectional view of the holding table of a modification apparatus. It is a figure which shows peeling operation | movement of the protective tape by a modification apparatus. It is a figure which shows peeling operation | movement of the protective tape by a modification apparatus.

  An embodiment of the present invention will be described below with reference to the drawings. In the embodiment, the case where the entire back surface is uniformly ground and the protective tape attached to the surface of a flat semiconductor wafer (hereinafter referred to as “wafer” as appropriate) is peeled off will be described in detail. In addition, a protective tape is contained in the adhesive tape of this invention.

  FIG. 1 is a front view showing an overall configuration of a protective tape peeling apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view showing a schematic configuration of a main part of the protective tape peeling apparatus. In addition, the protective tape peeling apparatus of a present Example is corresponded to an adhesive tape peeling apparatus.

  As shown in FIG. 1, the protective tape peeling device includes a holding table 1, a tape supply unit 2, a peeling mechanism 3, and a tape recovery unit 4.

  As shown in FIG. 2, the holding table 1 is a metal chuck table having a plurality of suction holes 5 on the surface. The holding table 1 is not limited to metal and may be formed of a porous material.

  The holding table 1 is supported by a movable base 7 supported so as to be slidable back and forth along a pair of left and right rails 6 arranged horizontally in the front and rear. The movable base 7 is screw-driven by a screw shaft 9 that is driven forward and backward by a pulse motor 8.

  The tape supply unit 2 guides the peeling tape Ts derived from the raw roll to the peeling unit 10 described later.

  The peeling mechanism 3 is constituted by main parts such as the peeling unit 10 and the detector 11.

  A support frame 13 made of an aluminum drawing material is fixed across a pair of left and right vertical frames 12 erected on the apparatus base. A box-shaped base 14 is connected to the left and right central portion of the support frame 13. Further, a lifting platform 16 supported so as to be slidable up and down via a pair of left and right vertical rails 15 provided on the base 14 is moved up and down by a ball shaft connected and driven by a motor 17. The peeling unit 10 is mounted on the lifting platform 16.

  The lifting platform 16 is configured in a hollow frame shape penetrating vertically. The peeling unit 10 is provided at the inner lower portion of the side plate 18 provided on the left and right sides of the lifting platform 16. A support frame 19 is fixed across the side plates 18. A peeling member 20 is attached to the center of the support frame 19.

  The peeling member 20 has a plate shape shorter than the diameter of the wafer W, and is formed in a tapered shape that tapers toward the tip. The peeling member 20 is fixed in a slanted and inclined posture.

  As shown in FIG. 3, the detector 11 includes a plurality of photoelectric sensors 26 arranged in a line so as to be equal to or larger than the diameter of the wafer W. The detector 11 is fixedly arranged at the lower end of the support frame 13. That is, when the peeling member 20 and the holding table 1 are horizontally moved so as to cross relatively, the peeling member 20 and the holding table 1 are arranged so as to follow from the rear of the peeling member 20.

  In the peeling mechanism 3, a supply guide roller 21 is pivotally supported behind the side plate 18 so as to be freely rotatable. A plurality of collecting guide rollers 22, nip rollers 23, and tension rollers 24 are disposed above the peeling unit 10.

  The collection guide roller 22 is pivotally supported so as to be freely rotatable. The tension roller 24 is provided on the support arm 25 so as to be freely rotatable, and is provided so as to be swingable via the support arm 25. Therefore, the tension roller 24 gives an appropriate tension to the peeling tape Ts wound around the guide.

  The collection guide roller 22 and the tension roller 24 are configured as wide rollers having a length larger than the diameter of the wafer W, and the outer peripheral surfaces thereof are hard-to-bond surfaces coated with fluororesin.

  The supply guide roller 21 is configured as a narrow roller that is longer than the width of the peeling tape Ts and shorter than the diameter of the wafer W.

  The tape recovery unit 4 winds and recovers the release tape Ts sent from the release unit 10.

  Next, one-round operation of the above-described embodiment apparatus will be described with reference to FIGS.

  The wafer W to which the protective tape PT after the back surface grinding is attached is placed on the holding table 1 by a transfer robot (not shown). The holding table 1 holds the wafer W by suction.

  As shown in FIG. 4, the holding table 1 that holds the wafer W by suction moves from the standby position to the application start position of the peeling tape Ts. That is, the tip of the peeling member 20 moves to a position where it contacts the end of the wafer W. Next, as shown in FIG. 5, the motor 17 operates to lower the peeling unit 10 to a predetermined height. That is, the peeling tape Ts wound around the peeling member 20 is pressed and attached to the end of the protective tape PT on the wafer W.

  Thereafter, the holding table 1 moves forward as shown in FIG. At this time, the peeling tape Ts is attached to the protective tape PT by the peeling member 20. At the same time, the protective tape PT is integrally peeled off from the surface of the wafer W while the peeling tape Ts is folded back by the peeling member 20. In synchronism with the peeling operation, the peeling tape Ts is fed out from the tape supply unit 2, and the peeling tape Ts to which the used protective tape PT is attached is taken up and collected by the tape collecting unit 4.

  Further, in the process of peeling off the protective tape PT, as shown in FIG. 7, the detector 11 follows the peeling operation of the protective tape PT by the peeling member 20 from the detector 11 on the surface of the wafer W from which the protective tape PT has been peeled off. Of light. The detector 11 receives the reflected light from the surface of the wafer W, converts the light intensity into a signal, and transmits the signal to the control unit 26.

  The control unit 26 makes a determination by comparing the reference value of the light intensity level stored in advance in a storage device such as a memory with the actually measured value detected by the determination unit 27. That is, if the measured value is less than the reference value, it is determined that an abnormal portion such as a crack or a crack has occurred on the wafer W. The abnormal location is identified from the encoder that detects the moving distance of the holding table 1, the number of pulses of the pulse motor 8, the light receiving position of the detector 11, and the like, and the position coordinates of the abnormal location are recorded. The position coordinates can be read from the storage device and displayed on a monitor or the like for confirmation.

  When the protective tape PT is completely peeled from the surface of the wafer W, the peeling unit 10 is raised and returned to the initial position to be ready for the next process.

  The wafer W from which the protective tape PT has been peeled moves to the delivery position by the holding table 1.

  This completes one round of the operation of the embodiment device, and thereafter, the same operation is repeated until the predetermined number is reached.

  According to the above-described embodiment apparatus, even when the wafer W is partially sucked and held by the holding table 1, it is possible to accurately detect an abnormal portion such as a crack or a chip. That is, when an abnormal part is detected, the abnormal part can be identified from the detected position coordinates, so that a prompt treatment can be performed. For example, it is possible to quickly remove debris and the like. Further, defective wafers W can be removed from the production line. Therefore, it is possible to prevent the apparatus and the production line from being stopped unnecessarily.

  The present invention can also be implemented in the following forms.

  (1) In the above embodiment, the description has been given by taking as an example a flat wafer W whose entire back surface is uniformly ground, but as shown in FIGS. 8 to 10, a wafer having an annular convex portion formed on the back surface outer periphery is used. May be.

  That is, the wafer W is back-grinded in a state where the protective tape PT is applied to the surface on which the pattern is formed and the surface is protected. The back surface is ground (back grind) leaving an outer peripheral portion of about 2 mm in the radial direction. In other words, a flat recess b is formed on the back surface and processed into a shape in which the annular protrusion r remains along the outer periphery thereof. For example, the processing is performed such that the depth d of the flat recess b is several hundred μm and the wafer thickness t in the grinding region is several tens μm. Accordingly, the annular protrusion r formed on the outer periphery of the back surface functions as an annular rib that increases the rigidity of the wafer W, and suppresses bending deformation of the wafer W during handling and other processing steps.

  When the wafer W is used, it is preferable to use the following holding table in the apparatus. Since only the configuration of the holding table is different from that of the above-described embodiment apparatus, the same components are only given the same reference numerals, and only different components are described in detail.

  As shown in FIG. 11, the holding table 1 </ b> A is provided with a recess 30 formed with a diameter close to the diameter of the grinding area on the back surface of the wafer W. A plurality of suction grooves 32 that act on the annular convex portion r of the wafer W are formed on the surface of the annular convex portion 31 on the outer peripheral portion of the concave portion 30. The suction groove 32 is connected in communication with an external vacuum source 33.

  In addition, an air supply hole 35 for pressurizing a space 34 formed by the flat recess b of the wafer W and the recess 30 of the holding table 1A is formed. The air supply hole 35 is connected in communication with an air supply device 36 installed outside. Furthermore, a needle valve for pressure control that communicates the space 34 with the outside is provided on the side wall of the annular protrusion 31. The air supply device 36 corresponds to the pressurizer of the present invention.

  Further, the holding table 1A is supported by a movable base 7 supported so as to be slidable back and forth along a pair of left and right rails 6 arranged horizontally in the front and rear direction, as in the above embodiment. The movable base 7 is screw-driven by a screw shaft 9 that is driven forward and backward by a pulse motor 8.

  Next, a circuit operation of the embodiment apparatus will be described with reference to FIGS.

  The wafer W to which the protective tape PT after the back surface grinding is attached is placed on the annular convex portion 31 of the holding table 1A so that the annular convex portion r on the back surface of the wafer overlaps by a transfer robot (not shown).

  When the wafer W is placed, the holding table 1A sucks and holds the annular convex portion r of the wafer W by the suction groove 32 formed in the annular convex portion 31. Thereafter, the air supply device 36 is operated to start supplying air to the space 34 of the holding table 1A sealed by the wafer W. At this time, as shown in FIG. 12, the space 34 is pressurized until the surface of the wafer W slightly bulges upward.

  When the inside of the space 34 reaches a predetermined pressure, the holding table 1A holding the wafer W by suction moves from the standby position to the application start position of the peeling tape Ts. Next, the motor 17 is operated to lower the peeling unit 10 to a predetermined height. That is, the peeling tape Ts wound around the peeling member 20 is pressed and attached to the end of the protective tape PT on the wafer W.

  Thereafter, the holding table 1A moves forward as shown in FIG. At this time, the peeling tape Ts is affixed to the protective tape PT while being pressed by the peeling member 20 so as to return the upward curve of the wafer W to a flat state. At the same time, the protective tape PT is integrally peeled off from the surface of the wafer W while the peeling tape Ts is folded back by the peeling member 20. In synchronism with the peeling operation, the peeling tape Ts is fed out from the tape supply unit 2, and the peeling tape Ts to which the used protective tape PT is attached is taken up and collected by the tape collecting unit 4.

  Further, in the process of peeling off the protective tape PT, the light from the detector 11 is irradiated on the surface of the wafer W from which the protective tape PT has been peeled off, following the peeling operation of the protective tape PT by the peeling member 20. The detector 11 receives the reflected light from the surface of the wafer W, converts the light intensity into a signal, and transmits the signal to the control unit 26.

  The control unit 26 determines whether or not the actual measurement value is within the reference value of the light intensity level stored in advance in a storage device such as a memory. If the measured value exceeds or falls below a predetermined set range, it is determined that an abnormal portion such as a chip or a crack has occurred on the wafer W. For example, in the abnormal part 40 where the crack has occurred as shown in FIG. The abnormal location is specified from the encoder that detects the moving distance of the holding table 1A, the number of pulses of the pulse motor 8, the light receiving position of the detector 11, and the like, and the position coordinates of the abnormal location are recorded.

  In this embodiment, since the wafer W to be detected is slightly bulged upward, the received light intensity of the reflected light detected by the detector 11 varies depending on the curvature of the wafer W. Therefore, mapping data is created in advance and stored in the storage device of the control unit 26 based on the correlation between the irradiation position of the light and the level change of the light intensity of the reflected light through experiments and simulations.

  When the protective tape PT is completely peeled from the surface of the wafer W, the peeling unit 10 is raised and returned to the initial position to prepare for the next processing.

  This completes one round of the operation of the embodiment device, and thereafter, the same operation is repeated until the predetermined number is reached.

  According to the above-described embodiment apparatus, even when the reinforcing annular convex portion r is formed on the back surface and the entire back surface of the wafer W cannot be sucked and held by the flat chuck table, it can be sucked and held. In addition, the circuit formation surface of the flat recess r of the wafer W is thinned and the rigidity is lowered. However, by attaching a gas to the space 34 formed by the holding table 1A and the wafer W and applying pressure, the bonding is performed. It is possible to avoid the circuit forming surface from being recessed and deformed by pressing during attachment. That is, the release tape Ts can be adhered to the protective tape PT.

  Furthermore, when an abnormal part such as a crack or a chip is generated by supplying gas to the space 34 and pressurizing it. Gas is slightly leaking from the abnormal part. That is, the cracked portion is slightly expanded to facilitate detection. Therefore, when an abnormal part is detected, it is possible to quickly remove debris and the like based on the position coordinates. Further, defective wafers W can be removed from the production line. Therefore, it is possible to prevent the apparatus and the production line from being stopped unnecessarily.

  In addition, the said Example apparatus is not limited to the wafer W in which the cyclic | annular convex part r was formed in the back surface, The whole back surface as described in the said main Example can be utilized also for the flat wafer W ground uniformly. Is possible.

  (2) In both the above embodiments, the position of the detector 11 where the light is irradiated may be just before the protective tape PT is peeled off by the peeling member 20. In this case, when the protective tape PT is peeled off, the tensile force concentrates on the separation boundary line along the peeling member 20 and acts on the cracked portion. That is, the cracked portion is slightly opened but easily opened.

  (3) In the above embodiment, the lowering of the peeling unit 10 is controlled and the peeling tape Ts is attached to the protective tape PT. However, the holding table 1 is moved up and down with respect to the peeling unit 10 that does not move up and down. You can also. Alternatively, the holding tables 1 and 1A may be fixed and the peeling unit 10 may be moved.

  (4) In the above embodiment, the detector 11 in which the photoelectric sensors are arranged in a line is used, but the present invention is not limited to this detector. For example, the optical camera may be tracked from behind the peeling member 20 to image the surface of the wafer W, and a crack or the like may be determined from the image data. Alternatively, a line sensor may be used.

  (5) In each of the above embodiments, the protective tape PT is completely peeled from the wafer W even if an abnormal part is detected. However, when the abnormal part is detected, the peeling operation is stopped to remove debris and the like. Also good.

  (6) In each of the above embodiments, the present invention can also be applied to the case where a double-sided adhesive tape having a reinforcing support plate such as stainless steel or glass substrate having substantially the same shape as the wafer W is peeled off from the wafer W. it can.

DESCRIPTION OF SYMBOLS 1 ... Holding table 2 ... Tape supply part 3 ... Peeling mechanism 4 ... Tape collection | recovery part 10 ... Peeling unit 11 ... Detector 20 ... Peeling member 26 ... Control part 27 ... Discrimination part PT ... Protection tape Ts ... Peeling tape W ... Semiconductor wafer

Claims (4)

An adhesive tape peeling method for peeling an adhesive tape affixed to a semiconductor wafer,
Including a peeling process in which the adhesive tape is peeled off from the semiconductor wafer by peeling off the peeling tape while the peeling tape is attached to the adhesive tape by a peeling member and folded;
In the peeling process, an inspection process for inspecting cracks in the semiconductor wafer by following the detector from the back of the peeling member;
An adhesive tape peeling method comprising: In the adhesive tape peeling method of Claim 1,
In the peeling process, the outer periphery of the semiconductor wafer is held by an annular holding table, and the peeling tape is attached to the pressure-sensitive adhesive tape while supplying gas to the hollow interior of the holding table and applying pressure. Method. An adhesive tape peeling apparatus for peeling an adhesive tape attached to a semiconductor wafer,
A holding table for holding the semiconductor wafer;
A peeling tape supply mechanism for supplying a strip-shaped peeling tape toward the semiconductor wafer;
A peeling mechanism that peels off the peeling tape with the peeling member and peels it off from the semiconductor wafer as a unit after attaching the peeling tape to the semiconductor wafer on the holding table,
A horizontal drive mechanism that relatively horizontally moves so that the holding table and the peeling member intersect,
A detector for detecting cracks in the semiconductor wafer following from the rear of the peeling member;
A tape recovery mechanism for winding and recovering the release tape integrated with the protective tape;
An adhesive tape peeling apparatus comprising: In the adhesive tape peeling apparatus according to claim 3,
The holding table is an annular shape that holds the outer periphery of the semiconductor wafer;
A pressurizer that supplies gas to the internal space of the holding table and pressurizes the semiconductor wafer on the holding table;
A control unit for adjusting the pressure inside the hollow of the holding table;
An adhesive tape peeling apparatus comprising:

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