Processing method of workpiece

Abstract

To provide a processing method for a workpiece capable of suppressing a residual adhesive agent on a device surface and wafer cracking caused by peeling stress when peeling a protective tape from the workpiece.SOLUTION: A processing method for a workpiece includes: an adhering step 1 of adhering a protective tape containing an adhesive agent, which is hardened by being irradiated with ultraviolet light, on an adhering face to a front face of the workpiece; a grinding step 2 of grinding a rear face of the workpiece while holding the front face side of the workpiece via the protective tape after the adhering step 1; a cleaning step 3 of cleaning a front face of the protective tape adhered to the workpiece after the grinding step 2; an ultraviolet light irradiation step 4 of irradiating the protective tape with ultraviolet light after the cleaning step 3; and a peeling step 5 of peeling the protective tape from the workpiece after the ultraviolet light irradiation step 4. In the peeling step 5, peeling is implemented while measuring a load when peeling the protective tape and in a case where the load is equal to or more than a predetermined threshold, an error is reported.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for processing a workpiece.

Background Art

[0002] In a semiconductor device manufacturing process, grinding is performed on the back surface (the surface opposite to the patterned surface) of a semiconductor wafer with a BG (back grind) tape applied to protect devices formed on the front surface of the semiconductor wafer. After grinding, a DC (dicing) tape with an annular frame attached to its outer periphery is adhered to the back surface of the wafer, and the BG tape adhered to the front surface is peeled off.

[0003] Conventionally, BG tapes that use an adhesive cured by ultraviolet irradiation have been employed to suppress wafer cracking caused by peeling stress and adhesive residue remaining on the device surface. In a grinding apparatus that grinds the back surface of a wafer, since the chuck table continues to suck the wafer during grinding, grinding debris generated during grinding enters between the wafer and the chuck table and adheres to the BG tape surface. Grinding debris adhering to the BG tape surface is removed, for example, by a cleaning mechanism that cleans the BG tape surface with a sponge (foamed elastic resin) as disclosed in Patent Document 1.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, in cleaning with a sponge as described in Patent Document 1, the cleaning effect on the BG tape surface decreases as the sponge deteriorates, and as a result, the curing effect of the adhesive by ultraviolet irradiation also decreases. Similarly, the curing effect of the adhesive also decreases due to the deterioration of the ultraviolet irradiation lamp. If ultraviolet irradiation failure occurs due to the deterioration of the sponge or ultraviolet lamp, adhesive residue may remain on the device surface, potentially causing wafer cracking due to peel stress.

[0006] This invention has been made in view of the above problems, and its purpose is to provide a method for processing a workpiece that can suppress adhesive residue on the device surface and wafer cracking due to peeling stress when peeling a protective tape from the workpiece. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the present invention provides a method for processing a workpiece, which is a method for processing a plate-shaped workpiece, and includes: an attachment step of attaching a protective tape having an adhesive on its adhesive surface that hardens when irradiated with ultraviolet light to the surface of the workpiece; a grinding step after the attachment step of holding the surface side of the workpiece through the protective tape and grinding the back side of the workpiece; a cleaning step after the grinding step of cleaning the surface of the protective tape attached to the workpiece; an ultraviolet irradiation step after the cleaning step of irradiating the protective tape with ultraviolet light; and a peeling step after the ultraviolet irradiation step of peeling the protective tape off the workpiece, wherein the peeling step is performed while measuring the load applied when peeling off the protective tape, and an error is reported if the load exceeds a predetermined threshold.

[0008] Furthermore, in the workpiece processing method of the present invention, in the peeling step, the protective tape is peeled off the workpiece by rotating the pair of rollers in opposite directions while the protective tape is sandwiched between the pair of rollers from both sides, and instead of measuring the load, the peeling is performed while measuring the rotational torque applied to the pair of rollers when peeling off the protective tape, and an error may be reported if the rotational torque is above a predetermined threshold. [Effects of the Invention]

[0009] This invention can suppress adhesive residue on the device surface and wafer cracking due to peeling stress when peeling protective tape from a workpiece. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a flowchart showing the flow of the workpiece processing method according to the embodiment. [Figure 2] Figure 2 is a side view showing one state of the adhesion step shown in Figure 1. [Figure 3] Figure 3 is a side view showing a partial cross-section of one state of the grinding step shown in Figure 1. [Figure 4] Figure 4 is a side view showing a partial cross-section of one state of the grinding step shown in Figure 1. [Figure 5] Figure 5 is a side view showing a partial cross-section of one state of the cleaning step shown in Figure 1. [Figure 6] Figure 6 is a perspective view showing one state of the cleaning step shown in Figure 5. [Figure 7] Figure 7 is a side view showing one state of the ultraviolet irradiation step shown in Figure 1. [Figure 8] Figure 8 is a side view showing one state of the peeling step shown in Figure 1. [Figure 9] Figure 9 is a side view showing one state of the peeling step in the first modified example. [Figure 10] Figure 10 is a side view showing one state of the peeling step in the second modified example. [Modes for carrying out the invention]

[0011] Embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by those skilled in the art, and those that are substantially the same. Moreover, the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the present invention.

[0012] [Embodiment] A method for processing a workpiece 10 according to an embodiment of the present invention will be described with reference to the drawings. The method for processing a workpiece 10 is a method for processing a plate-shaped workpiece 10. Figure 1 is a flowchart showing the flow of the method for processing a workpiece 10 according to an embodiment. The method for processing a workpiece 10 according to the embodiment comprises an adhesion step 1, a grinding step 2, a cleaning step 3, an ultraviolet irradiation step 4, and a peeling step 5.

[0013] (Adhesion Step 1) Figure 2 is a side view showing one state of the adhesion step 1 shown in Figure 1. The adhesion step 1 is a step of attaching a protective tape 20, which has an adhesive on its adhesive surface 21 that hardens when irradiated with ultraviolet light 73 (see Figure 7), to the surface 11 of the workpiece 10.

[0014] The workpiece 10 is, for example, a disc-shaped semiconductor wafer, optical device wafer, or other wafer with a substrate made of silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium arsenide (GaAs), or other semiconductor material. Alternatively, the workpiece 10 is a disc-shaped wafer with a substrate made of materials such as sapphire (Al2O3), glass, or quartz. Glass includes, for example, alkali glass, alkali-free glass, soda-lime glass, lead glass, borosilicate glass, quartz glass, etc.

[0015] The workpiece 10 includes, for example, a plurality of planned dividing lines set in a grid pattern on a surface 11 of a substrate, and devices formed in respective regions partitioned by the planned dividing lines. The device is, for example, an integrated circuit such as IC (Integrated Circuit) or LSI (Large Scale Integration), an image sensor such as CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), or MEMS (Micro Electro Mechanical Systems).

[0016] A back surface 12 located on the opposite side from the surface 11 on which the devices are formed is ground to a predetermined finished thickness in a grinding step 2 described later. After being thinned, for example, the workpiece 10 is divided along the planned dividing lines and singulated into individual device chips. Note that the workpiece 10 is not limited to a disk shape.

[0017] The protective tape 20 is a sheet for protecting the surface 11 side of the workpiece 10 where the devices are formed. The protective tape 20 is composed of a non-adhesive and flexible resin base layer, and an adhesive and flexible resin adhesive layer. The adhesive contained in the adhesive layer includes an ultraviolet curable resin that is cured when irradiated with ultraviolet light 73 (see FIG. 7), such as polyolefin.

[0018] In the attaching step 1 shown in FIG. 2, a roller 30 is used to fix the protective tape 20 to the surface 11 of the workpiece 10. In the attaching step 1, first, the workpiece 10 is placed on a holding table 31 such that the surface 11 side of the workpiece 10 faces upward. The holding table 31 has, for example, a suction holding mechanism that sucks the holding surface by negative pressure or an electrostatic adsorption mechanism, and can fix the workpiece 10 held on the holding surface (upper surface). Next, in the attaching step 1, the adhesive surface 21 of the protective tape 20, which is larger in size than the entire surface 11 of the workpiece 10, is aligned so as to face the surface 11 of the workpiece 10.

[0019] In the first application step, the roller 30 is then rolled on the back surface 22 of the protective tape 20, opposite to the adhesive surface 21, from one end to the other of the workpiece 10. The protective tape 20, pressed against the surface 11 of the workpiece 10 by the roller 30, adheres tightly to the surface 11 of the workpiece 10 with the adhesive side 21 conforming to the unevenness of the surface 11, while the back surface 22 is formed flat. After the protective tape 20 is attached to the surface 11 of the workpiece 10 in the first application step, the protective tape 20 is cut along the outer edge of the workpiece 10 as appropriate.

[0020] (Grinding step 2) Figures 3 and 4 are side views showing a partial cross-section of one state of grinding step 2 shown in Figure 1. Grinding step 2 is performed after bonding step 1. Grinding step 2 is a step in which the surface 11 side of the workpiece 10 is held via the protective tape 20 and the back surface 12 side of the workpiece 10 is ground.

[0021] In the grinding step 2 of the embodiment, the back surface 12 of the workpiece 10 is ground by the grinding device 40 to thin it to a predetermined finish thickness. The grinding device 40 comprises a holding table 41, a grinding unit 42, and a grinding fluid supply unit (not shown).

[0022] The holding table 41 holds the workpiece 10 on its surface 11 side via a protective tape 20 and is rotatable around a vertical axis. The holding table 41 has a suction holding mechanism that, for example, uses negative pressure to attract the holding surface. The grinding unit 42 includes a spindle 43 which is a rotating shaft member, a grinding wheel 44 attached to the lower end of the spindle 43, and a grinding wheel 45 mounted on the lower surface of the grinding wheel 44. The grinding wheel 44 is rotatable on a rotation axis parallel to the axis of the holding table 41.

[0023] In grinding step 2, first, the workpiece 10 is held by suction on the holding surface of the holding table 41 via the protective tape 20. Next, with the holding table 41 rotating around its axis, the grinding wheel 44 is rotated around its axis. Then, grinding fluid is supplied to the processing point by a grinding fluid supply unit (not shown), and the grinding wheel 45 of the grinding wheel 44 is brought closer to the holding table 41 at a predetermined feed rate, so that the back surface 12 of the workpiece 10 is ground with the grinding wheel 45, as shown in Figure 4, and thinned to a predetermined finish thickness.

[0024] During this process, grinding chips are generated when the back surface 12 of the workpiece 10 is ground. While grinding step 2 is being performed, the holding table 41 generates negative pressure at its holding surface to hold the workpiece 10, and the holding surface is sucking the front surface 11 of the workpiece 10. That is, the front surface 11 of the workpiece 10 is being sucked to the holding table 41 via the protective tape 20. Due to this suction, grinding chips may enter between the protective tape 20 attached to the front surface 11 of the workpiece 10 and the holding surface of the holding table 41, and adhere to the protective tape 20.

[0025] (Washing step 3) Figure 5 is a side view showing a partial cross-section of one state of cleaning step 3 shown in Figure 1. Figure 6 is a perspective view showing one state of cleaning step 3 shown in Figure 5. Cleaning step 3 is performed after grinding step 2. Cleaning step 3 is a step of cleaning the surface of the protective tape 20 attached to the workpiece 10.

[0026] In other words, grinding debris adhering to the protective tape 20 in grinding step 2 is washed away in washing step 3. In washing step 3 of this embodiment, the workpiece 10 is held by the transport unit 50, and the washing unit 60 washes the surface (back side 22) of the protective tape 20 attached to the workpiece 10.

[0027] The transport unit 50 transports the workpiece 10, whose back surface 12 has been ground in grinding step 2, to the cleaning position of the cleaning unit 60. The transport unit 50 includes a transport arm 51 that is movable by a drive mechanism (not shown), and a disc-shaped holding part 52 fixed to the tip of the transport arm 51. The holding part 52 has, for example, a suction holding mechanism that uses negative pressure to attract the suction surface 53 on the lower side, or an electrostatic suction mechanism, and holds the ground surface 13 of the workpiece 10 by adsorption with the suction surface 53. The transport unit 50 can transport the workpiece 10 between the holding table 41 of the grinding device 40 and a position facing the cleaning unit 60 (the position shown in Figures 5 and 6).

[0028] The cleaning unit 60 faces the surface 11 of the workpiece 10, which is held by the transport unit 50, from below, with the grinding surface 13 facing it. In this embodiment, the cleaning unit 60 has a sponge (foamed elastic resin) facing the lower side of the workpiece 10. The sponge has the function of cleaning the protective tape 20 attached to the surface 11 of the workpiece 10. The cleaning unit 60 moves relative to the protective tape 20 with the sponge in contact with the protective tape 20, and cleans and removes grinding debris by rubbing the surface of the protective tape 20. In the example shown in Figures 5 and 6, the sponge has a three-bladed propeller shape that can rotate around a vertical axis, but it may also be disc-shaped, or a sponge roller that can rotate around a horizontal axis. It may also be able to reciprocate horizontally.

[0029] In the cleaning step 3, first, the suction surface 53 of the transport unit 50 is placed opposite the holding table 41 of the grinding device 40, and the suction surface 53 is brought into contact with the ground surface 13 of the workpiece 10 after grinding, which is held on the holding table 41, to hold it by suction. Next, the transport unit 50 transports the workpiece 10 to a position opposite the cleaning unit 60.

[0030] In cleaning step 3, the sponge of the cleaning unit 60 is brought into contact with the surface (back surface 12) of the protective tape 20 attached to the surface 11 side of the workpiece 10, and the sponge is rotated around a vertical axis to clean the back surface 12 of the protective tape 20. This allows the sponge to rub off the back surface 12 of the protective tape 20, removing any grinding debris attached to the protective tape 20. The workpiece 10, with its cleaned protective tape 20, is then transported by the transport unit 50 to the ultraviolet irradiation device 70 shown in Figure 7, which will be described later.

[0031] (UV irradiation step 4) Figure 7 is a side view showing one state of the ultraviolet irradiation step 4 shown in Figure 1. The ultraviolet irradiation step 4 is performed after the cleaning step 3. The ultraviolet irradiation step 4 is the step of irradiating the protective tape 20 with ultraviolet light 73.

[0032] In the ultraviolet irradiation step 4 of the embodiment, ultraviolet light 73 is irradiated onto the protective tape 20 by the ultraviolet irradiation device 70 shown in Figure 7. The ultraviolet irradiation device 70 comprises a holding table 71 and a light source 72 that irradiates ultraviolet light 73 onto the workpiece 10 held on the holding table 71. In the example shown in Figure 7, only one light source 72 is positioned in the center above the holding table 71, but multiple light sources 72 may be positioned. Also, the holding table 71 and the light sources 72 may be relatively movable.

[0033] In the ultraviolet irradiation step 4 shown in Figure 7, first, the workpiece 10 is placed on the holding table 71 so that the side with the protective tape 20 attached to it (surface 11) faces upward. The holding table 71 has, for example, a suction holding mechanism that attracts the holding surface by negative pressure, or an electrostatic adsorption mechanism, and holds the workpiece 10 on its holding surface (upper surface). Next, ultraviolet light 73 is irradiated from the light source 72 toward the protective tape 20 for a predetermined time. The adhesive containing the ultraviolet-curable resin on the adhesive surface 21 of the protective tape 20 hardens when irradiated with ultraviolet light 73, and the adhesive strength decreases.

[0034] (Peeling step 5) Figure 8 is a side view showing one state of peeling step 5 as shown in Figure 1. Peeling step 5 is performed after ultraviolet irradiation step 4. Peeling step 5 is the step of peeling the protective tape 20 from the workpiece 10. In peeling step 5, the peeling is performed while measuring the load applied when peeling off the protective tape 20, and an error is reported if the load exceeds a predetermined threshold.

[0035] In the peeling step 5 shown in Figure 8, the protective tape 20 is peeled off the workpiece 10 using a peeling unit 80 capable of gripping the ends of the protective tape 20 from both sides. In peeling step 5, first, the workpiece 10 is placed on the holding table 81 so that the surface 11 to which the protective tape 20 is attached faces upward. The holding table 81 has, for example, a suction holding mechanism that attracts the holding surface by negative pressure, or an electrostatic adsorption mechanism, and can fix the workpiece 10 held on the holding surface (upper surface). It is preferable that the holding table 81 is also used as the holding table 71 of the ultraviolet irradiation device 70.

[0036] In peeling step 5, a peeling point is formed at the end of the protective tape 20 attached to the workpiece 10 by a peeling point forming mechanism (not shown). The peeling point forming mechanism includes, for example, a peeling member such as a sponge (foamed elastic resin) or silicone rubber (elastic resin) that contacts the outer edge of the protective tape 20, and a moving mechanism that moves the peeling member. The moving mechanism moves the peeling member diagonally upward toward the center of the workpiece 10 from the position where it is in contact with the outer edge of the protective tape 20 attached to the workpiece 10. As the peeling member peels the protective tape 20 away from the workpiece 10, a peeling point is formed at the end of the protective tape 20.

[0037] In peeling step 5, the end of the protective tape 20, which will serve as the peeling starting point, is then clamped from both sides by the peeling unit 80. Next, the peeling unit 80 is moved to the opposite side of the peeling starting point and upward, and the protective tape 20 is pulled, thereby peeling the protective tape 20 from the workpiece 10 held on the holding table 81.

[0038] In peeling step 5, the peeling unit 80 performs peeling while measuring the load applied when pulling the protective tape 20. The measured load is output to a control device (not shown), for example. The control device stores predetermined thresholds in advance, and if the measured load is greater than or equal to the predetermined threshold, it causes an error to be reported to a notification device (not shown). The notification device notifies the operator, for example, by emitting at least one of sound and / or light.

[0039] In UV irradiation step 4, if the protective tape 20 is not sufficiently irradiated with UV light 73 and the adhesive surface 21 of the protective tape 20 does not harden sufficiently, the adhesive strength will not decrease sufficiently, and a large load will be placed on the peeling unit 80 in peeling step 5. In peeling step 5, if a load exceeding a threshold is applied, it can be determined that the irradiation with UV light 73 was insufficient. In this case, for example, peeling step 5 may be interrupted and UV irradiation step 4 may be performed again.

[0040] [First variation] Figure 9 is a side view showing one state of peeling step 5 in the first modified example. In peeling step 5 of the first modified example, the dicing tape 110 is attached to the back surface 12 side of the workpiece 10, and the protective tape 20 is peeled off from the workpiece 10 after it has been fixed to the frame 100 and the dicing tape 110.

[0041] The frame 100 is an annular plate member made of metal or resin, having an opening larger than the outer diameter of the workpiece 10. The dicing tape 110 is a sheet with an outer diameter larger than the opening of the frame 100, and is attached to the back side of the frame 100 so as to cover the opening of the frame 100.

[0042] The dicing tape 110 may be composed of, for example, a base layer made of an elastic synthetic resin and an adhesive layer laminated on the base layer and made of an elastic and adhesive synthetic resin, or it may not have an adhesive layer and be made of a thermoplastic resin. The workpiece 10 is positioned at a predetermined position in the opening of the frame 100 and fixed to the frame 100 and the dicing tape 110 by the grinding surface 13 side adhering to the dicing tape 110.

[0043] The timing for attaching the dicing tape 110 to the grinding surface 13 of the workpiece 10 is preferably, for example, after the ultraviolet irradiation step 4. In the peeling step 5 of the first modified example, the grinding surface 13 side of the workpiece 10 is held on the holding surface of the holding table 81 via the dicing tape 110, and then the outer edge of the frame 100 is fixed with clamp members 82. Multiple clamp members 82 are arranged around the holding table 81 and are capable of clamping the outer edge of the frame 100. The subsequent steps of the peeling step 5 of the first modified example are the same as the steps of the peeling step 5 in the embodiment shown in Figure 8.

[0044] [Second variation] Figure 10 is a side view showing one state of peeling step 5 in the second modified example. In peeling step 5 of the second modified example, a peeling unit 90 is used to peel the protective tape 20 from the workpiece 10, instead of the peeling unit 80 shown in Figure 8.

[0045] The peeling unit 90 includes a pair of rollers 92 and 93. The pair of rollers 92 and 93 are rotatable around an axis parallel to the holding surface of the holding table 91 that holds the workpiece 10. The axes of the pair of rollers 92 and 93 are also parallel to each other. The pair of rollers 92 and 93 are spaced apart by the thickness of the protective tape 20. The pair of rollers 92 and 93 sandwich the protective tape 20 between them from both sides and rotate in opposite directions to pull the protective tape 20 in a direction along the rotation.

[0046] In the peeling step 5 of the second modified example, similar to the peeling step 5 of the embodiment shown in Figure 8, first, the workpiece 10 is placed on the holding table 91 so that the side with the protective tape 20 attached to it (the surface 11) faces upward. The holding table 91 has, for example, a suction holding mechanism that attracts the holding surface by negative pressure, or an electrostatic adsorption mechanism, and can fix the workpiece 10 held on the holding surface (upper surface). It is preferable that the holding table 91 is also used as the holding table 71 of the ultraviolet irradiation device 70. Next, in peeling step 5, a peeling starting point is formed on the end of the protective tape 20 attached to the workpiece 10 by a peeling starting point forming mechanism (not shown).

[0047] In the peeling step 5 of the second modified example, the end of the protective tape 20, which will serve as the peeling starting point, is then guided between a pair of rollers 92 and 93 and held from both sides. Next, the pair of rollers 92 are rotated in the direction of the arrows shown in Figure 10, and the protective tape 20 is pulled in the opposite direction from the peeling starting point and upward, thereby peeling the protective tape 20 from the workpiece 10 held on the holding table 91.

[0048] In the peeling step 5 of the second modified example, peeling is performed while measuring the rotational torque applied to the pair of rollers 92 and 93 of the peeling unit 90. The measured rotational torque is output to, for example, a control device (not shown). The control device stores a predetermined threshold value in advance, and if the measured rotational torque is greater than or equal to the predetermined threshold value, it causes an error to be reported to a notification device (not shown). Alternatively, the control device may calculate the load on which the peeling unit 90 pulls the protective tape 20 based on the acquired rotational torque, store a predetermined threshold value for the load in advance, and if the calculated load is greater than or equal to the predetermined threshold value, it may cause an error to be reported to a notification device (not shown).

[0049] As described above, in the processing method for the workpiece 10 of the embodiment and each modified example, it is possible to detect whether the adhesive surface 21 of the protective tape 20 has sufficiently hardened by monitoring the load applied when peeling off the protective tape 20. In other words, it is possible to detect whether the irradiation with ultraviolet light 73 to harden the adhesive surface 21 in the ultraviolet irradiation step 4 was sufficient. By detecting insufficient ultraviolet irradiation during peeling, if a load exceeding a predetermined threshold is applied, measures such as interrupting peeling and irradiating with ultraviolet light 73 again can be taken. Therefore, adhesive residue on the device surface (surface 11) and cracking due to peeling stress when peeling off the protective tape 20 from the workpiece 10 can be suppressed.

[0050] It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core principles of the present invention. [Explanation of symbols]

[0051] 10 Workpiece 11 Surface 12 Back side 13. Grinding surface 20 protective tapes 21 Adhesive side 22 Reverse side (front side) 30 Laura 40 Grinding equipment 50 transport units 60 Washing Units 70 Ultraviolet irradiation device 73 Ultraviolet rays 80, 90 peeling units 92, 93 Laura

Claims

1. A method for processing a plate-shaped workpiece, A bonding step of bonding a protective tape having an adhesive on its bonding surface that hardens when exposed to ultraviolet light to the surface of the workpiece, After the adhesion step, a grinding step is performed in which the surface side of the workpiece is held via the protective tape and the back side of the workpiece is ground. After the grinding step, a cleaning step is performed to clean the surface of the protective tape attached to the workpiece. After the cleaning step, the protective tape is irradiated with ultraviolet light in an ultraviolet irradiation step, The UV irradiation step is followed by a peeling step of peeling the protective tape off the workpiece, In the peeling step, The peeling process was carried out while measuring the load applied when peeling off the protective tape. An error is reported if the load exceeds a predetermined threshold. A method for processing a workpiece, characterized by the features described above.

2. In the peeling step, The protective tape is peeled off the workpiece by rotating the pair of rollers in opposite directions while the protective tape is sandwiched between them from both sides. Instead of measuring the load, the peeling process is performed while measuring the rotational torque applied to the pair of rollers during the peeling of the protective tape. An error is reported if the rotational torque exceeds a predetermined threshold. The method for processing a workpiece as described in feature 1.

Images