JP2016201471A - Workpiece processing method - Google Patents

Abstract

A method for processing a workpiece capable of preventing peeling of a functional layer is provided. A processing method of a workpiece in which a functional layer is laminated in a region on the surface of a substrate and a device including the functional layer is formed in a plurality of regions partitioned by a division line. It is. A laser beam having a wavelength having an absorptivity with respect to the functional layer is irradiated from the surface 11a side of the workpiece to form two laser processing grooves 21 along the planned division line. A protective member 23 is attached to the surface side of the workpiece, and a laser beam L2 having a wavelength that is transparent to the substrate is directed from the back surface 11b side of the workpiece to an intermediate region sandwiched between the two laser processing grooves. The functional layer in the intermediate region is peeled off from the substrate by irradiating with the Further, a modified layer is formed inside the substrate, an external force is applied to the workpiece, the workpiece is broken starting from the modified layer, and divided into a plurality of device chips. [Selection] Figure 4

Description

  The present invention relates to a method for processing a workpiece including a functional layer such as a low-k film.

  In an electronic device typified by a mobile phone, a device chip including an electronic circuit (device) such as an IC is an essential component. For example, device chips are obtained by dividing the surface of a wafer (substrate) made of a material such as silicon with a plurality of division lines called streets, forming devices in each region, and then dividing the wafer along the streets. Can be manufactured.

  In recent years, a technology for insulating between device wirings by an insulating film (Low-k film) having a low dielectric constant has been put into practical use. By using a low-k film for insulation between wirings, even if the wiring interval is narrowed due to miniaturization of the process, the capacitance generated between the wirings can be suppressed and signal delay can be suppressed. Thereby, the processing capability of the device is maintained high.

  The Low-k film described above is usually laminated in multiple layers, and its mechanical strength is low. Therefore, for example, when the wafer is cut with a cutting blade and divided into device chips, the Low-k film is peeled off from the wafer. On the other hand, a processing method for cutting a wafer after irradiating a laser beam to remove a part of the Low-k film has been proposed (for example, see Patent Document 1).

  In this processing method, first, a laser beam is irradiated along the street from the surface side of the wafer, and a part of the Low-k film is removed by ablation. Thereafter, if the region from which the Low-k film has been removed is cut with a cutting blade, the wafer can be divided while suppressing the possibility of peeling of the Low-k film.

  Also, a processing method has been proposed in which a low-k film is removed by ablation and then a wafer is divided without using a cutting blade for the purpose of increasing the bending strength of the device chip and narrowing the width of the planned dividing line. (For example, refer to Patent Document 2). In this processing method, after the removal of the low-k film, a laser beam having a wavelength that is difficult to be absorbed by the wafer is condensed to form a modified layer by multiphoton absorption inside the wafer, and the wafer is formed starting from this modified layer. It is broken.

JP 2003-320466 A JP 2012-89709 A

  However, when the Low-k film is removed by ablation, a part of the nearby wafer is denatured due to the influence of generated heat or the like. Since the crack originating from the modified layer described above extends while avoiding the altered region, in this case, the wafer cannot be divided properly in the region where the low-k film has been removed. Device failure was likely to occur.

  This invention is made | formed in view of this problem, The place made into the objective is to provide the processing method of the to-be-processed object which can prevent peeling of a functional layer.

  According to the present invention, a functional layer is stacked in a region on the surface side of a substrate including a plurality of planned division lines set in a lattice shape, and the functional layer is included in a plurality of regions partitioned by the planned division lines. Is formed by irradiating a laser beam having a wavelength that is absorptive with respect to the functional layer from the surface side of the workpiece provided with the functional layer, and along the dividing line. A groove forming step for forming two laser-processed grooves, a protective member attaching step for attaching a protective member to the surface side of the workpiece after performing the groove forming step, and the protective member attachment After performing the step, the intermediate region is irradiated with a laser beam having a wavelength that is transparent to the substrate from the back side of the workpiece toward the intermediate region sandwiched between the two laser processing grooves. The functional layer is peeled from the substrate After performing the transmission laser irradiation step for forming the modified layer inside the substrate and the transmission laser irradiation step, an external force is applied to the workpiece, and the workpiece is broken from the modified layer as a starting point. Splitting into a plurality of device chips, the transmitting laser irradiation step positioning the condensing point of the laser beam having the transmitting wavelength near or outside the surface of the substrate, and the functional layer After performing the functional layer peeling step and the functional layer peeling step, the condensing point of the laser beam having a wavelength having the transparency is positioned inside the substrate, and the modification is inside the substrate. And a modified layer forming step of forming a layer. A method of processing a workpiece is provided.

  In the present invention, after performing the transmission laser irradiation step, an expanded tape is attached to the back side of the workpiece, the protective member is peeled from the workpiece, and the functional layer is peeled from the substrate. It is preferable to carry out a re-seat step of removing together with the protective member.

  In the processing method of the workpiece according to the present invention, after irradiating the functional layer with a laser beam having a wavelength that is absorptive with respect to the functional layer from the surface side of the workpiece, after forming two laser processing grooves along the division line Irradiate a laser beam with a wavelength that is transparent to the substrate from the back side of the workpiece toward the intermediate region sandwiched between the two laser processing grooves, and peel off the functional layer remaining in the intermediate region from the substrate As a result, the functional layer can be removed without altering the substrate in the vicinity of the intermediate region.

  Therefore, a laser beam having a wavelength that is transmissive to the substrate is irradiated from the back side of the workpiece toward the intermediate region, a modified layer is formed inside the substrate, and an external force is applied to the workpiece. Thus, the workpiece can be divided into a plurality of device chips by extending a crack from the modified layer to the intermediate region. That is, according to the method for processing a workpiece according to the present invention, the workpiece can be appropriately divided in the intermediate region from which the functional layer has been removed, and peeling of the functional layer can be prevented.

FIG. 1A is a perspective view schematically showing a workpiece, and FIG. 1B is a cross-sectional view schematically showing a part of the workpiece. FIG. 2A is a perspective view schematically showing the groove forming step, and FIG. 2B is a cross-sectional view schematically showing the groove forming step. It is a perspective view which shows a protection member sticking step typically. FIG. 4A is a perspective view schematically showing the functional layer peeling step of the transmission laser irradiation step, and FIG. 4B is a cross-sectional view schematically showing the functional layer peeling step. It is sectional drawing which shows typically the modified layer formation step of the transmission laser irradiation step. It is a perspective view which shows a replacement step typically. 7A and 7B are partial cross-sectional side views schematically showing the dividing step, and FIG. 7C is a cross-sectional view schematically showing the dividing step.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The workpiece processing method according to this embodiment includes a groove forming step (see FIGS. 2A and 2B), a protective member attaching step (see FIG. 3), and a transmission laser irradiation step (see FIG. 4). A), FIG. 4B and FIG. 5), a replacement step (see FIG. 6) and a division step (see FIG. 7A, FIG. 7B and FIG. 7C).

  In the groove forming step, a laser beam having a wavelength that is easy to be absorbed by the functional layer from the surface side of the workpiece (wavelength that has an absorptivity with respect to the functional layer) is irradiated to form two laser processing grooves along the planned dividing line. To do. In the protective member attaching step, the protective member is attached to the surface side of the workpiece.

  In the transmission laser irradiation step, a laser beam having a wavelength that is difficult to be absorbed by the wafer (substrate) from the back surface side of the workpiece (wavelength having transparency to the wafer) is irradiated and sandwiched between two laser processing grooves. The functional layer remaining in the intermediate region is peeled from the wafer (functional layer peeling step), and a modified layer is formed inside the wafer (modified layer forming step).

  In the pasting step, an expanded tape is attached to the back side of the workpiece, the protective member is peeled from the workpiece, and the functional layer peeled from the wafer is removed together with the protective member. In the dividing step, an external force is applied to the workpiece, the workpiece is broken starting from the modified layer, and divided into a plurality of device chips. Hereinafter, the processing method of the workpiece which concerns on this embodiment is explained in full detail.

  FIG. 1A is a perspective view schematically showing a workpiece processed in the present embodiment, and FIG. 1B is a cross-sectional view schematically showing a part of the workpiece. . As shown in FIGS. 1A and 1B, the workpiece 11 includes a wafer (substrate) 13 serving as a base material and a functional layer 15 stacked on the surface 13 a side of the wafer 13.

  The wafer 13 is, for example, a circular plate made of a semiconductor material such as silicon or a ceramic such as sapphire. On the other hand, the functional layer 15 includes a metal film functioning as a wiring, an insulating film (including a low-k film) that insulates the wiring, a semiconductor film, and the like. As the Low-k film in the functional layer 15, for example, an inorganic insulating film made of an inorganic material such as SiOF or SiOB, or an organic insulating film made of a polyimide-based or parelin-based polymer can be used.

  The surface 11a (surface 13a of the wafer 13) side of the workpiece 11 is divided into a plurality of areas by a plurality of division lines (streets) 17 set in a lattice shape. The device 19 is formed. Each device 19 includes the functional layer 15 described above as a component. Further, a part of the functional layer 15 is also disposed in a region that overlaps the planned division line 17.

  In the workpiece processing method according to the present embodiment, first, a groove forming step for forming two laser-processed grooves along the division line is performed. FIG. 2A is a perspective view schematically showing the groove forming step, and FIG. 2B is a cross-sectional view schematically showing the groove forming step. This groove forming step is performed by, for example, the laser processing apparatus 2 shown in FIG.

  The laser processing apparatus 2 includes a chuck table 4 that holds a workpiece 11. The chuck table 4 is connected to a rotation mechanism (not shown) such as a motor, and rotates around a rotation axis parallel to the vertical direction (Z-axis direction). Further, a moving mechanism (not shown) is provided below the chuck table 4, and the chuck table 4 is moved in the horizontal direction (X-axis direction, Y-axis direction) by this moving mechanism.

  The upper surface of the chuck table 4 serves as a holding surface that holds the back surface 11 b (the back surface 13 b of the wafer 13) side of the workpiece 11. A negative pressure of a suction source (not shown) acts on the holding surface through a flow path formed inside the chuck table 4 to generate a suction force for sucking the workpiece 11.

  A laser processing unit 6 is disposed above the chuck table 4. A camera 8 for imaging the workpiece 11 is installed at a position adjacent to the laser processing unit 6. The laser processing unit 6 condenses the laser beam L1 pulse-oscillated by a laser oscillator (not shown) and irradiates the functional layer 15 in the region overlapping the division planned line 17. The laser oscillator is configured to be able to oscillate a laser beam L1 having a wavelength that is easily absorbed by the functional layer 15 (absorbing wavelength).

  In the groove forming step according to the present embodiment, first, the workpiece 11 is placed on the chuck table 4 so that the back surface 11b of the workpiece 11 and the holding surface of the chuck table 4 face each other, and a suction source is placed on the holding surface. Apply negative pressure. Thereby, the workpiece 11 is held on the chuck table 4 with the surface 11a side exposed upward.

  Next, the chuck table is moved and rotated to align the position of the laser processing unit 6 above the processing start position (for example, the end portion of the planned division line 17 to be processed). Then, while irradiating the laser beam L1 from the laser processing unit 6 toward the surface 11a of the workpiece 11, the chuck table 4 is parallel to the division line 17 to be processed (in FIG. 2A, the X-axis direction). ).

  At this time, the position of the condensing point P1 of the laser beam L1 is adjusted to the vicinity of the surface 13a of the wafer 13. Thereby, the functional layer 15 formed on the surface 11a side of the workpiece 11 is ablated along the division line 17 to be processed, and a single laser processing groove 21 from which a part of the functional layer 15 is removed is formed. it can.

  After a single laser processing groove 21 is formed along the planned division line 17 to be processed, a position separated within the same division line 17 (in FIG. 2A and FIG. 2B, in the Y-axis direction). Another laser processing groove 21 is formed at a position separated from the other. This procedure is repeated, and, for example, when the two laser processing grooves 21 are formed on all the division planned lines 17, the groove forming step is completed.

  After the groove forming step, a protective member attaching step of attaching a protective member to the surface 11a side of the workpiece 11 is performed. FIG. 3 is a perspective view schematically showing a protective member attaching step. As shown in FIG. 3, the protective member 23 is a circular film-like member made of a material such as a resin, and a glue layer having an adhesive force is provided on the surface 23a side.

  Moreover, the protection member 23 is formed in the magnitude | size which can cover the whole surface 11a of the to-be-processed object 11, for example. In the protective member attaching step, as shown in FIG. 3, the protective member 23 is attached to the workpiece 11 by bringing the surface 23 a of the protective member 23 into contact with the surface 11 a of the workpiece 11.

  After the protective member attaching step, a transmission laser irradiation step of irradiating a laser beam having a wavelength (wavelength having transparency) that is difficult to be absorbed by the wafer 13 from the back surface 11b side of the workpiece 11 is performed. This transmission laser irradiation step includes a functional layer peeling step for peeling the functional layer 15 remaining in the intermediate region sandwiched between the two laser processing grooves 21 in each division line 17 from the wafer 13, and a modification to the inside of the wafer 13. A modified layer forming step of forming a quality layer.

  FIG. 4A is a perspective view schematically showing the functional layer peeling step of the transmission laser irradiation step, and FIG. 4B is a cross-sectional view schematically showing the functional layer peeling step. The functional layer peeling step is performed by, for example, the laser processing apparatus 12 shown in FIG. The basic configuration of the laser processing apparatus 12 is the same as that of the laser processing apparatus 2 used in the groove forming step.

  That is, the laser processing apparatus 12 includes a laser processing unit 16 that collects the laser beam L2 pulse-oscillated by a laser oscillator (not shown) and irradiates the workpiece 11 on the chuck table 14. A camera 18 for imaging the workpiece 11 is installed at a position adjacent to the laser processing unit 16. However, the laser oscillator of the laser processing apparatus 12 is configured to be able to oscillate a laser beam L2 having a wavelength that is difficult to be absorbed by the wafer 13 (wavelength having transparency).

  In the functional layer peeling step, first, the workpiece 11 is placed on the chuck table 14 so that the back surface 23b of the protective member 23 attached to the workpiece 11 and the holding surface of the chuck table 14 face each other. The negative pressure of the suction source is applied to Thereby, the workpiece 11 is held on the chuck table 14 with the back surface 11b side exposed upward.

  Next, the chuck table 14 holding the workpiece 11 is moved and rotated to align the position of the laser processing unit 16 above the processing start position. The processing start position is, for example, an end portion of an intermediate region sandwiched between the two laser processing grooves 21 in the planned division line 17 to be processed.

  Then, while irradiating the laser beam L2 from the laser processing unit 16 toward the back surface 11b of the workpiece 11, the chuck table 14 is parallel to the division line 17 to be processed (X-axis direction in FIG. 4A). Move to. That is, the laser beam L2 is irradiated from the back surface 11b side of the workpiece 11 toward the intermediate region sandwiched between the two laser processing grooves 21. At this time, the position of the condensing point P2 of the laser beam L2 is adjusted to be near or outside the surface 13a of the wafer 13 (below the surface 13a in FIG. 4B).

  As a result, the functional layer 15 remaining in the intermediate region sandwiched between the two laser processing grooves 21 in the division target line 17 to be processed can be peeled off from the wafer 13. The functional layer 15a (see FIG. 5) peeled from the wafer 13 adheres to the glue layer provided on the surface 23a side of the protective member 23. This procedure is repeated, and for example, when the functional layer 15 remaining in the intermediate region in all the division lines 17 is peeled from the wafer 13, the functional layer peeling step ends.

  In this functional layer peeling step, the functional layer 15 is peeled off using a laser beam L2 having a wavelength that is difficult to be absorbed by the wafer 13, so that the wafer 13 is not altered by heat generated by ablation. In addition, conditions, such as the power of the laser beam L2 and a spot diameter, are adjusted so that the functional layer 15 can be peeled appropriately.

  After the functional layer peeling step, a modified layer forming step is subsequently performed. FIG. 5 is a cross-sectional view schematically showing the modified layer forming step of the transmission laser irradiation step. The modified layer forming step is performed by the same laser processing apparatus 12 as the functional layer peeling step.

  In the modified layer forming step, first, the chuck table 14 holding the workpiece 11 is moved and rotated to align the position of the laser processing unit 16 above the processing start position. The processing start position is, for example, an end portion of a region (intermediate region) where the functional layer 15 is peeled off on the division line 17 to be processed.

  Then, while irradiating the laser beam L2 from the laser processing unit 16 toward the back surface 11b of the workpiece 11, the chuck table 14 is parallel to the division line 17 to be processed (X-axis direction in FIG. 4A). Move to. That is, the laser beam L2 is irradiated from the back surface 11b side of the workpiece 11 toward the area where the functional layer 15 is peeled off. At this time, the position of the condensing point P3 of the laser beam L2 is adjusted to the inside of the wafer 13 (between the front surface 13a and the back surface 13b in FIG. 5).

  Thereby, the modified layer 25 by multiphoton absorption can be formed along the region where the functional layer 15 of the division line 17 to be processed is peeled off. For example, when the modified layer 25 is formed along all the planned division lines 17, the modified layer forming step ends.

  After the transmission laser irradiation step including the functional layer peeling step and the modified layer forming step, an expansion tape is applied to the back surface 11b side of the workpiece 11, and a replacement step of peeling the protective member 23 from the workpiece 11 is performed. carry out. FIG. 6 is a perspective view schematically showing the replacement step.

  In the pasting step, as shown in FIG. 6, the expanded tape 27 having a diameter larger than that of the workpiece 11 is pasted on the back surface 11 b side of the workpiece 11. Further, an annular frame 29 is fixed to the outer peripheral portion of the expanding tape 27. Further, the protective member 23 is peeled off from the surface 11 a of the workpiece 11.

  As described above, the functional layer 15 a peeled from the wafer 13 is attached to the glue layer provided on the surface 23 a side of the protective member 23. Therefore, the functional layer 15a peeled from the wafer 13 can be removed together with the protective member 23 by peeling the protective member 23 from the surface 11a of the workpiece 11.

  After the replacement step, a dividing step is performed in which an external force is applied to the workpiece 11 and the workpiece 11 is broken from the modified layer 25 to be divided into a plurality of device chips. 7A and 7B are partial cross-sectional side views schematically showing the dividing step, and FIG. 7C is a cross-sectional view schematically showing the dividing step. The dividing step is performed by, for example, the expansion device 22 shown in FIGS. 7 (A) and 7 (B).

  The expansion device 22 includes a workpiece support unit 24 that supports the workpiece 11, and a cylindrical expansion drum 26 that expands an expanded tape 27 attached to the back surface 11 b side of the workpiece 11. . The inner diameter of the expansion drum 26 is larger than the diameter of the workpiece 11, and the outer diameter of the expansion drum 26 is smaller than the inner diameter of the frame 29.

  The workpiece support unit 24 includes an annular frame support table 28 that supports the frame 29. The upper surface of the frame support table 28 is a support surface on which the frame 29 is placed. A plurality of clamps 30 for fixing the frame 29 are provided on the outer peripheral portion of the frame support table 28.

  Below the workpiece support unit 24, an elevating mechanism 32 is provided. The elevating mechanism 32 includes a cylinder case 34 fixed to a base (not shown) and a piston rod 36 inserted into the cylinder case 34. A frame support table 28 is fixed to the upper end portion of the piston rod 36. By the elevating mechanism 32, the upper surface (support surface) of the frame support table 28 moves between a reference position having a height equivalent to the upper end of the expansion drum 26 and an expansion position below the upper end of the expansion drum 26.

  In the dividing step, first, as shown in FIG. 7A, a frame 29 is placed on the upper surface of the frame support table 28 aligned with the reference position, and this frame 29 is fixed by a clamp 30. As a result, the upper end of the expansion drum 26 comes into contact with the expanded tape 27 existing between the outer peripheral edge of the workpiece 11 and the inner peripheral edge of the frame 29.

  Next, the workpiece support unit 24 is lowered by the elevating mechanism 32, and the upper surface of the frame support table 28 is moved to the extended position below the upper end of the expansion drum 26 as shown in FIG. As a result, the expansion drum 26 rises relative to the frame support table 28, and the expanded tape 27 is pushed up by the expansion drum 26 and expands.

  As described above, the modified layer 25 serving as the starting point of the fracture is formed on the workpiece 11 along the planned dividing line 17. Therefore, when the expanding tape 27 is expanded and an external force is applied, the workpiece 11 is divided into a plurality of device chips 31 starting from the modified layer 25. In the processing method of the workpiece according to the present embodiment, the wafer 13 hardly changes in the region (intermediate region) where the functional layer 15 of the planned division line 17 is peeled off, so that the modification is performed as shown in FIG. The workpiece 11 can be appropriately divided by extending a crack from the material layer 25 to this region.

  As described above, in the processing method of the workpiece according to the present embodiment, the laser beam L1 having a wavelength that is easily absorbed by the functional layer 15 (wavelength having absorption) is irradiated from the surface 11a side of the workpiece 11 and divided. After forming the two laser processing grooves 21 along the planned line 17, two laser beams L <b> 2 having a wavelength that is difficult to be absorbed by the wafer (substrate) 13 (wavelength having transparency) are formed from the back surface 11 b side of the workpiece 11. Irradiation is performed toward the intermediate region sandwiched between the laser processing grooves 21, and the functional layer 15 remaining in the intermediate region is peeled off from the wafer 13, so that the functional layer 15 can be removed without altering the wafer 13 in the vicinity of the intermediate region. .

  Therefore, the laser beam L2 having a wavelength that is difficult to be absorbed by the wafer 13 is irradiated from the back surface 11b side of the workpiece 11 toward the region (intermediate region) where the functional layer 15 is peeled off, and the modified layer 25 is formed inside the wafer 13. After the formation, by applying an external force to the workpiece 11, the workpiece 11 can be divided into a plurality of device chips 31 by extending a crack in the region where the functional layer 15 is peeled from the modified layer 25. That is, according to the processing method of the workpiece which concerns on this embodiment, the workpiece can be divided | segmented appropriately in the area | region where the functional layer 15 was removed, and peeling of the functional layer 15 can be prevented.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the groove forming step, a laser beam is applied to the workpiece 11 in the form of a frame unit in which a large-diameter adhesive tape is attached to the back surface 11b side of the workpiece 11 and an annular frame is fixed to the outer peripheral portion of the adhesive tape. The processing groove 21 may be formed.

  In the functional layer peeling step and the modified layer forming step of the above embodiment, the functional layer 15 remaining in the intermediate region of all the division lines 17 is peeled from the wafer 13 and then modified along the division lines 17. The quality layer 25 is formed. Immediately after the functional layer 15 remaining in the intermediate region of any planned division line 17 is peeled from the wafer 13, the modified layer 25 is formed along the division line 17. You can also.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

11 Workpiece 11a Front 11b Back 13 Wafer (Substrate)
13a Front surface 13b Back surface 15, 15a Functional layer 17 Scheduled line (street)
DESCRIPTION OF SYMBOLS 19 Device 21 Laser processing groove 23 Protective member 23a Front surface 23b Back surface 25 Modified layer 27 Expanding tape 29 Frame 31 Device chip L1, L2 Laser beam P1, P2, P3 Condensing point 2 Laser processing apparatus 4 Chuck table 6 Laser processing unit 8 Camera DESCRIPTION OF SYMBOLS 12 Laser processing apparatus 14 Chuck table 16 Laser processing unit 18 Camera 22 Expansion apparatus 24 Workpiece support unit 26 Expansion drum 28 Frame support table 30 Clamp 32 Lifting mechanism 34 Cylinder case 36 Piston rod

Claims (2)

A functional layer is stacked in a region on the surface side of the substrate including a plurality of division lines set in a lattice shape, and a device including the functional layer is formed in a plurality of areas partitioned by the division lines. A processing method for a workpiece,
A groove forming step of irradiating a laser beam having a wavelength having an absorptivity with respect to the functional layer from a surface side of the workpiece provided with the functional layer to form two laser processed grooves along the division line;
After carrying out the groove forming step, a protective member attaching step for attaching a protective member to the surface side of the workpiece;
After carrying out the protective member attaching step, irradiate a laser beam having a wavelength transparent to the substrate from the back side of the workpiece toward the intermediate region sandwiched between the two laser processing grooves. A transmission laser irradiation step of peeling the functional layer in the intermediate region from the substrate and forming a modified layer inside the substrate;
A step of applying an external force to the work piece after performing the transmission laser irradiation step, and breaking the work piece starting from the modified layer to divide the work piece into a plurality of device chips;
The transmitted laser irradiation step includes:
A functional layer peeling step for positioning a condensing point of a laser beam having a wavelength near the surface of the substrate or outside the substrate, and peeling the functional layer from the substrate;
After performing the functional layer peeling step, a modified layer forming step of positioning a condensing point of the laser beam having the transmitting wavelength inside the substrate and forming the modified layer inside the substrate; A method for processing a workpiece, comprising:   After performing the transmission laser irradiation step, an expanded tape is attached to the back side of the workpiece, the protective member is peeled off from the workpiece, and the functional layer peeled from the substrate is removed from the protective member. The processing method of the workpiece according to claim 1, wherein a replacement step is also performed.

Images