JP2015023135A - Wafer processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer processing method that is able to easily manufacture a device in which the surface of a substrate is laminated with a functional layer and the rear face of the substrate is covered with a metal film to serve as an electrode.SOLUTION: A wafer processing method comprises: a modified layer formation step in which a wafer with devices formed in areas sectioned by dividing lines drawn on a functional layer 21 with which the surface of a substrate 20 has been laminated, is subjected to a laser radiation from the rear face thereof such that the point of convergence of a laser beam with any wavelength, having transmissivity, is positioned to an inner part of an area corresponding to each dividing line, and a modified layer is formed inside the substrate; a protective member attaching step in which a protective member 3 is attached to the surface of the functional layer; a rear face polishing and dividing step in which the rear face of the substrate is polished to provide the wafer with predetermined thickness and the wafer is divided into separate devices along the dividing lines along which the modified layer is formed; a metal film coating step in which the rear face of the substrate is covered with a metal film; and a metal film breaking step in which the wafer is expanded to break the metal film along the separate devices.

Description

  In the present invention, a wafer in which devices are formed in a plurality of regions partitioned by a plurality of division lines formed in a lattice pattern on a functional layer stacked on the surface of a substrate is divided into individual devices along the division lines. The present invention relates to a wafer processing method for dividing and coating a metal film on the back surface of a substrate of each device.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by division lines arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and ICs, LSIs, power devices, and SAW devices are partitioned in these partitioned regions. And so on. Then, by cutting the semiconductor wafer along the planned dividing line, the region where the device is formed is divided to manufacture individual devices.

  The above-described cutting along the wafer division line is usually performed by a cutting device called a dicer. The cutting apparatus includes a chuck table for holding a workpiece, a cutting means for cutting the workpiece held on the chuck table, and a cutting feed means for relatively moving the chuck table and the cutting means. An image pickup means for detecting a region to be cut is provided. The cutting means includes a rotary spindle, a cutting blade mounted on the spindle, and a drive mechanism that rotationally drives the rotary spindle. The cutting blade is composed of a disk-shaped base and an annular cutting edge mounted on the outer periphery of the side surface of the base. The cutting edge is fixed to the base by electroforming, for example, diamond abrasive grains having a particle size of about 3 μm. It is formed to a thickness of about 20 μm (see, for example, Patent Document 1).

  However, since power device wafers and SAW device wafers are configured by laminating functional layers on the surfaces of SiC substrates and GaN substrates having high Mohs hardness, cutting with a cutting blade is difficult.

  On the other hand, as a method of dividing the wafer along the planned dividing line, there is a laser processing method in which a pulsed laser beam having transparency to the wafer is used, and a focused laser beam is irradiated inside the region to be divided and irradiated with the pulsed laser beam. Has been tried. The dividing method using this laser processing method is to irradiate the wafer with a pulsed laser beam having a wavelength having transparency to the wafer from one side of the wafer along the planned dividing line. By continuously forming a modified layer along the planned dividing line inside and internally applying an external force along the planned dividing line whose strength has been reduced by the formation of the modified layer, the wafer is applied to each device. This is a technique of dividing (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 2002-66865 JP 2010-52014 A

  Thus, in the power device wafer and SAW device wafer, the functional layer is laminated on the surface of the substrate, and the back surface of the substrate is coated with a metal film such as gold as an electrode. There is a problem that it is difficult to position the condensing point of the laser beam from the back side to the inside, and it is impossible to form the modified layer along the planned dividing line inside the wafer.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to easily make a device in which a functional layer is laminated on the surface of a substrate and a metal film serving as an electrode is coated on the back surface of the substrate. Another object of the present invention is to provide a method for processing a wafer that can be manufactured.

In order to solve the above main technical problem, according to the present invention, a wafer in which devices are formed in a plurality of regions partitioned by a plurality of division lines formed in a lattice pattern on a functional layer stacked on the surface of a substrate. Is a wafer processing method in which a metal film is coated on the back surface of the substrate of each device while dividing the device into individual devices along a division line.
A condensing point of a laser beam having a wavelength that is transparent to the substrate is irradiated from the back surface side of the substrate constituting the wafer within the region corresponding to the planned division line, and is irradiated along the planned division line inside the substrate. A modified layer forming step of forming a modified layer;
A protective member attaching step for attaching a protective member to the surface of the functional layer constituting the wafer before or after the modified layer forming step;
The protective member side of the wafer is held on the chuck table of the grinding machine, the back surface of the substrate is ground to form the wafer to a predetermined thickness, and the wafer is divided into individual devices along the planned division line on which the modified layer is formed. Back grinding and splitting process,
A metal film coating step for coating a metal film on the back surface of the substrate constituting the wafer subjected to the back grinding and dividing step;
Extending the wafer on which the metal film coating step has been performed, and breaking the metal film along individual devices.
A method for processing a wafer is provided.

  The wafer processing method according to the present invention irradiates the condensing point of a laser beam having a wavelength having transparency to the substrate from the back surface side of the substrate constituting the wafer within the region corresponding to the division line. A modified layer forming step is performed in which a modified layer is formed along a planned division line, and the rear surface of the substrate is ground to form a wafer to a predetermined thickness and the modified layer is formed. After performing the back surface grinding and dividing process to divide the wafer into individual devices, the metal film coating process for coating the metal film on the back surface of the substrate constituting the wafer is performed, so that the laser beam is applied to the inside of the substrate constituting the wafer. It is possible to divide the wafer into individual devices by positioning the light condensing point and form a modified layer, and to form an electrode by coating a metal film on the back surface of the device It can be.

The perspective view and principal part expanded sectional view of the semiconductor wafer as a wafer used in the processing method of the wafer by this invention. Explanatory drawing which shows the protection member sticking process in the processing method of the wafer by this invention. The principal part perspective view of the laser processing apparatus for implementing the modified layer formation process in the processing method of the wafer by this invention. Explanatory drawing which shows the modified layer formation process in the processing method of the wafer by this invention. Explanatory drawing of the back surface grinding and division | segmentation process in the processing method of the wafer by this invention. Explanatory drawing of the metal film coating process in the processing method of the wafer by this invention. Explanatory drawing of the wafer support process in the processing method of the wafer by this invention. The perspective view of the tape expansion device for implementing the metal film fracture | rupture process in the processing method of the wafer by this invention. Explanatory drawing of the metal film fracture | rupture process in the processing method of the wafer by this invention. Explanatory drawing of the pick-up process in the processing method of the wafer by this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a wafer processing method according to the present invention will be described in detail with reference to the accompanying drawings.

  1A and 1B are a perspective view and an enlarged cross-sectional view of a main part of a semiconductor wafer as a wafer to be processed in the wafer processing method. A semiconductor wafer 2 shown in FIGS. 1A and 1B has a functional layer 21 in which a functional film for forming an insulating film and a circuit is laminated on a surface 20a of a substrate 20 made of a SiC substrate or a GaN substrate having a thickness of 600 μm. Are formed, and devices 23 such as a power device and a SAW device are formed in a plurality of regions partitioned by a plurality of division lines 22 formed in a lattice shape on the functional layer 21.

A method of processing a wafer in which the semiconductor wafer 2 described above is divided into individual devices 23 along the planned division line 22 and the back surface of the substrate of each device is coated with a metal film will be described.
First, in order to protect the device 23, the protective member 3 is attached to the surface 21a of the functional layer 21 laminated on the surface of the substrate 20 constituting the semiconductor wafer 2 (protective member attaching step). ). The protective member 3 can be a rigid hard plate such as a resin sheet such as a polyethylene film or a glass substrate. In addition, you may implement a protection member sticking process after the modified layer formation process mentioned later.

  Next, the protective member 3 side of the semiconductor wafer 2 is held on the chuck table, and the condensing point of the laser beam having a wavelength that is transmissive to the substrate 20 from the back side of the substrate 20 is set in a region corresponding to the division line 22. A modified layer forming step is performed in which irradiation is performed while being positioned inside, and a modified layer is formed in the substrate 20 along the planned division line 22. This modified layer forming step is performed using a laser processing apparatus 4 shown in FIG. A laser processing apparatus 4 shown in FIG. 3 includes a chuck table 41 that holds a workpiece, laser beam irradiation means 42 that irradiates a workpiece held on the chuck table 41 with a laser beam, and a chuck table 41 that holds the workpiece. An image pickup means 43 for picking up an image of the processed workpiece is provided. The chuck table 41 is configured to suck and hold the workpiece. The chuck table 41 is moved in a processing feed direction indicated by an arrow X in FIG. 3 by a processing feed means (not shown) and is also shown in FIG. 3 by an index feed means (not shown). It can be moved in the index feed direction indicated by the arrow Y.

  The laser beam application means 42 includes a cylindrical casing 421 arranged substantially horizontally. In the casing 421, pulse laser beam oscillation means including a pulse laser beam oscillator and repetition frequency setting means (not shown) are arranged. A condenser 422 for condensing the pulse laser beam oscillated from the pulse laser beam oscillating means is attached to the tip of the casing 421. The laser beam irradiating unit 42 includes a condensing point position adjusting unit (not shown) for adjusting the condensing point position of the pulsed laser beam condensed by the condenser 422.

  In the illustrated embodiment, the imaging means 43 attached to the tip of the casing 421 constituting the laser beam irradiation means 42 emits infrared rays to the workpiece in addition to a normal imaging device (CCD) that captures images with visible light. Infrared illumination means for irradiating, an optical system for capturing infrared light emitted by the infrared illumination means, an image pickup device (infrared CCD) for outputting an electrical signal corresponding to the infrared light captured by the optical system, and the like Then, the captured image signal is sent to a control means (not shown).

  In order to perform the modified layer forming step using the laser processing apparatus 4 described above, the protective member is applied to the semiconductor wafer 2 by performing the protective member attaching step on the chuck table 41 as shown in FIG. Place 3 side. Then, by operating a suction means (not shown), the semiconductor wafer 2 is held on the chuck table 41 via the protective member 3 (wafer holding step). Accordingly, in the semiconductor wafer 2 held on the chuck table 41, the back surface 20b of the substrate 20 is on the upper side. In this way, the chuck table 41 that sucks and holds the semiconductor wafer 2 is positioned directly below the imaging unit 43 by a processing feed unit (not shown).

  When the chuck table 41 is positioned immediately below the image pickup means 43, an alignment operation for detecting a processing region to be laser processed of the semiconductor wafer 2 is executed by the image pickup means 43 and a control means (not shown). In other words, the imaging unit 43 and a control unit (not shown) are divided division lines 22 formed in a predetermined direction of the functional layer 21 constituting the semiconductor wafer 2, and a laser beam irradiation unit 42 that irradiates a laser beam along the division division line 22. Image processing such as pattern matching for alignment with the condenser 422 is performed, and alignment of the laser beam irradiation position is performed. The alignment of the laser beam irradiation position is similarly performed on the division line 22 formed in the functional layer 21 constituting the semiconductor wafer 2 and extending in the direction orthogonal to the predetermined direction. At this time, the functional layer 21 constituting the semiconductor wafer 2 on which the division line 22 is formed is positioned on the lower side. However, as described above, the imaging unit 43 and the optical system that captures infrared rays and infrared rays. Since the image pickup device is configured with an image pickup device (infrared CCD) or the like that outputs an electrical signal corresponding to the above, it is possible to image the planned division line 22 through the back surface 20b of the substrate 20 constituting the wafer.

  If the division line 22 formed on the functional layer 21 constituting the semiconductor wafer 2 held on the chuck table 41 is detected and the laser beam irradiation position is aligned as described above, FIG. As shown in (a) of FIG. 4, the chuck table 41 is moved to the laser beam irradiation region where the condenser 422 of the laser beam irradiation means 42 for irradiating the laser beam is located, and one end of a predetermined division planned line 22 (FIG. 4A). (The left end in FIG. 4) is positioned directly below the condenser 422 of the laser beam irradiation means 42. Next, the condensing point P of the pulsed laser beam LB irradiated from the concentrator 422 is positioned at an intermediate portion in the thickness direction of the substrate 20 constituting the semiconductor wafer 2. Then, the chuck table 41 is moved at a predetermined feed speed in the direction indicated by the arrow X1 in FIG. 4A while irradiating a pulse laser beam having a wavelength having transparency to the substrate 20 from the condenser 422. Then, as shown in FIG. 4B, when the irradiation position of the condenser 422 of the laser beam irradiation means 42 reaches the position of the other end of the division planned line 22, the irradiation of the pulse laser beam is stopped and the chuck table 41 is stopped. Stop moving. As a result, the modified layer 210 is formed along the planned division line 22 inside the substrate 20 constituting the semiconductor wafer 2 (modified layer forming step).

The processing conditions in the modified layer forming step are set as follows, for example.
Light source: LD excitation Q switch Nd: YVO4 laser Wavelength: 532 nm pulse laser Repetition frequency: 25 kHz
Average output: 0.7W
Pulse width: 40 ns
Condensing spot diameter: φ2μm
Processing feed rate: 350 mm / sec

  The above-described modified layer forming step is performed on regions corresponding to all the division lines 22 formed on the semiconductor wafer 2.

  When the modified layer forming step is performed, the protective member 3 side of the semiconductor wafer 2 is held on the chuck table of the grinding apparatus, and the back surface of the substrate 20 is ground to form the semiconductor wafer 2 to a predetermined thickness. A back grinding / dividing step is performed in which the device is divided into individual devices 23 along the planned dividing line 22 on which the modified layer 210 is formed. This back grinding / dividing step is performed using a grinding apparatus 5 shown in FIG. A grinding apparatus 5 shown in FIG. 5A includes a chuck table 51 serving as a holding unit that holds a workpiece, and a grinding unit 52 that grinds the workpiece held on the chuck table 51. . The chuck table 51 is configured to suck and hold the workpiece on the upper surface, and is rotated in a direction indicated by an arrow 51a in FIG. 5A by a rotation driving mechanism (not shown). The grinding means 52 includes a spindle housing 521, a rotating spindle 522 that is rotatably supported by the spindle housing 521 and rotated by a rotation driving mechanism (not shown), a mounter 523 mounted on the lower end of the rotating spindle 522, and the mounter And a grinding wheel 524 attached to the lower surface of 523. The grinding wheel 524 includes an annular base 525 and a grinding wheel 526 that is annularly attached to the lower surface of the base 525, and the base 525 is attached to the lower surface of the mounter 523 with fastening bolts 527. ing.

  In order to carry out the back surface grinding and dividing step using the above-described grinding device 5, as shown in FIG. 5 (a), the surface of the semiconductor wafer 2 is adhered to the upper surface (holding surface) of the chuck table 51. The protective member 3 side that is present is placed. Then, the semiconductor wafer 2 is sucked and held on the chuck table 51 by the suction means (not shown) via the protective member 3 (wafer holding step). Accordingly, in the semiconductor wafer 2 held on the chuck table 51, the back surface 20b of the substrate 20 is on the upper side. If the semiconductor wafer 2 is sucked and held on the chuck table 51 via the protective member 3 in this way, the grinding means is rotated while rotating the chuck table 51 in the direction indicated by the arrow 51a in FIG. 52, the grinding wheel 524 is rotated in the direction indicated by the arrow 524a in FIG. 5A at, for example, 6000 rpm, and the grinding wheel 526 is formed as a work surface as shown in FIG. 5B. The substrate 20 is brought into contact with the back surface 20b of the substrate 20, and the grinding wheel 524 is ground and fed by a predetermined amount at a grinding feed rate of 1 μm / second, for example, as indicated by an arrow 524b (in a direction perpendicular to the holding surface of the chuck table 51). As a result, the back surface 20b of the substrate 20 of the semiconductor wafer 2 is ground so that the semiconductor wafer 2 is formed to a predetermined thickness (for example, 100 μm), and the modified division layer 210 is formed to reduce the strength. 22 is divided into individual devices 23. In addition, since the protection member 3 is stuck on the surface of the plurality of devices 23 that are divided individually, the form of the semiconductor wafer 2 is maintained without being separated.

  If the back surface grinding and dividing step described above is performed, a metal film coating step for coating the metal film on the back surface of the substrate 20 constituting the semiconductor wafer 2 is performed. This metal film coating step is performed using a sputtering apparatus 6 shown in FIG. A sputtering apparatus 6 shown in FIG. 6A includes a housing 62 that forms a sputtering chamber 61, and an electrostatic adsorption type holding that serves as an anode that is disposed in the sputtering chamber 61 of the housing 62 and holds a workpiece. To the table 63, a cathode 65 to which a target 64 made of a metal (for example, gold, silver, aluminum, etc.) disposed and opposed to the holding table 63 is attached; excitation means 66 for exciting the target 64; It comprises a high frequency power supply 67 for applying a high frequency voltage. The housing 62 is provided with a decompression port 621 that communicates with the decompression means (not shown) in the sputtering chamber 61 and an introduction port 622 that communicates with the sputtering gas supply means (not shown) within the sputtering chamber 61.

In order to perform the above-described metal film coating process using the sputtering apparatus 6 configured as described above, the substrate 20 constituting the semiconductor wafer 2 in which the above-described back surface grinding and dividing process is performed on the holding table 63 is performed. The protective member 3 side adhered to the surface is placed and held electrostatically. Therefore, in the semiconductor wafer 2 electrostatically held on the holding table 3, the back surface 20b of the substrate 20 is on the upper side. Next, the excitation means 66 is operated to excite the target 64 and a high frequency voltage of 40 kHz, for example, is applied to the cathode 65 from a high frequency power supply 67. Then, the decompression means (not shown) is operated to decompress the inside of the sputtering chamber 61 to about 10 ⁻² Pa to 10 ⁻⁴ Pa, and the sputtering gas supply means (not shown) is operated to introduce argon gas into the sputtering chamber 61. To generate plasma. Accordingly, the argon gas in the plasma collides with the target 64 made of a metal such as gold, silver, or aluminum attached to the cathode 65, and the metal particles scattered by the collision are applied to the back surface 20 b of the substrate 20 constituting the semiconductor wafer 2. A metal layer is deposited. As a result, the metal film 220 is coated on the back surface 20b of the substrate 20 as shown in FIG. The metal film 220 has a thickness set to 30 to 60 nm.

  If the metal film coating process described above is performed, the metal film breaking process is performed in which the semiconductor wafer 2 having the metal film 220 coated on the back surface 20b of the substrate 20 is expanded and the metal film 220 is broken along each device. To do. In order to perform this metal film breaking step, in the illustrated embodiment, a dicing tape is first attached to the back surface 20b of the substrate 20 constituting the semiconductor wafer 2, and the outer periphery of the dicing tape is supported by an annular frame, A wafer support process for peeling the protective member 3 is performed. That is, as shown in FIG. 7, the metal film 220 side covered with the back surface 20b of the substrate 20 constituting the semiconductor wafer 2 on the surface of the dicing tape T with the outer peripheral portion mounted so as to cover the opening of the annular frame F is provided. Affix. Then, the protective member 3 attached to the surface 21a of the functional layer 21 laminated on the surface of the substrate 20 is peeled off (wafer support step).

  Next, a dicing tape T on which the wafer support process has been performed is expanded, and a metal film breaking process for breaking the metal film 220 along each device 23 is performed. This metal film breaking step is carried out using a tape expansion device 7 shown in FIG. 8 includes a frame holding means 71 for holding the annular frame F, and a tape extending means for expanding the dicing tape T mounted on the annular frame F held by the frame holding means 71. 72. The frame holding means 71 includes an annular frame holding member 711 and a plurality of clamps 712 as fixing means provided on the outer periphery of the frame holding member 711. An upper surface of the frame holding member 711 forms a placement surface 711a on which the annular frame F is placed, and the annular frame F is placed on the placement surface 711a. The annular frame F placed on the placement surface 711 a is fixed to the frame holding member 711 by the clamp 712. The frame holding means 71 configured as described above is supported by the tape expanding means 72 so as to be able to advance and retreat in the vertical direction.

  The tape expansion means 72 includes a cylindrical expansion drum 721 as a pressing member disposed inside the annular frame holding member 711. The expansion drum 721 has an inner diameter and an outer diameter that are smaller than the inner diameter of the annular frame F and larger than the outer diameter of the semiconductor wafer 2 attached to the dicing tape T attached to the annular frame F. The expansion drum 721 includes a support flange 722 at the lower end. The tape expansion means 72 in the illustrated embodiment includes support means 73 that can advance and retract the annular frame holding member 711 in the vertical direction. The support means 73 includes a plurality of air cylinders 731 disposed on the support flange 722, and the piston rod 732 is connected to the lower surface of the annular frame holding member 711. As described above, the support means 73 including the plurality of air cylinders 731 has a predetermined amount from the reference position where the mounting surface 711 a is substantially flush with the upper end of the expansion drum 721 and the upper end of the expansion drum 721. Move up and down between the lower extended positions. Therefore, the support means 73 composed of a plurality of air cylinders 731 functions as expansion movement means for relatively moving the expansion drum 721 and the frame holding member 711 in the vertical direction.

  A metal film breaking step performed using the tape expansion device 7 configured as described above will be described with reference to FIG. That is, the annular frame F on which the dicing tape T on which the back surface 20b of the substrate 20 constituting the semiconductor wafer 2 is adhered is attached to the frame holding means 71 constituting the frame holding means 71 as shown in FIG. It is mounted on the mounting surface 711 a of the member 711 and fixed to the frame holding member 711 by the clamp 712. At this time, the frame holding member 711 is positioned at the reference position shown in FIG. Next, a plurality of air cylinders 731 as the support means 73 constituting the tape extending means 72 are operated to lower the annular frame holding member 711 to the extended position shown in FIG. 9B. Accordingly, the annular frame F fixed on the mounting surface 711a of the frame holding member 711 is also lowered, so that the dicing tape T mounted on the annular frame F is an expansion drum as shown in FIG. It expands by contacting the upper edge of 721 (tape expansion process). As a result, a tensile force acts radially on the metal film 220 adhered to the dicing tape T. Thus, when a radial tensile force acts on the metal film 220 adhered to the dicing tape T, the semiconductor wafer 2 is divided into the individual devices 23. The space between the devices 23 is widened, and the metal film 220 is broken along the outer periphery of the device 23.

  When the metal film breaking step is performed as described above, the pickup mechanism 8 is operated as shown in FIG. 10 and the device 23 positioned at a predetermined position by the pickup collet 81 (the substrate 20 is coated with the metal film 220 on the back surface). Are picked up (pickup process) and conveyed to a tray or die bonding process (not shown).

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, in the above-described embodiment, as the metal film breaking step for expanding the wafer subjected to the metal film coating step and breaking the metal film along each device, the back surface 20b of the substrate 20 constituting the semiconductor wafer 2 is applied. A dicing tape T is attached and the outer periphery of the dicing tape T is supported by an annular frame and the protective member 3 is peeled off. The dicing tape T on which the wafer supporting step is performed is expanded to expand the metal film 220. Although an example including a metal film breaking step that breaks along each device 23 has been shown, the protective member 3 in a state where the protective member 3 is adhered to the surface of the semiconductor wafer 2 on which the metal film coating step has been performed. Further, the semiconductor wafer 2 may be expanded to break the metal film 220 along individual devices.

2: Semiconductor wafer 20: Substrate 21: Functional layer 22: Planned division line 23: Device 210: Modified layer 220: Metal film 3: Protective member 4: Laser processing device 42: Laser beam irradiation means 422: Concentrator 5: Grinding Device 52: Grinding means 524: Grinding wheel 6: Sputtering device 61: Sputtering chamber 63: Holding table 7: Tape expanding device 72: Tape expanding device F: Ring frame T: Dicing tape

Claims (1)

A wafer in which devices are formed in a plurality of regions defined by a plurality of division lines formed in a lattice pattern on a functional layer stacked on the surface of the substrate is divided into individual devices along the division lines. A wafer processing method for coating a metal film on the back surface of a device substrate,
A condensing point of a laser beam having a wavelength that is transparent to the substrate is irradiated from the back surface side of the substrate constituting the wafer within the region corresponding to the planned division line, and is irradiated along the planned division line inside the substrate. A modified layer forming step of forming a modified layer;
A protective member attaching step for attaching a protective member to the surface of the functional layer constituting the wafer before or after the modified layer forming step;
The protective member side of the wafer is held on the chuck table of the grinding machine, the back surface of the substrate is ground to form the wafer to a predetermined thickness, and the wafer is divided into individual devices along the planned division line on which the modified layer is formed. Back grinding and splitting process,
A metal film coating step for coating a metal film on the back surface of the substrate constituting the wafer subjected to the back grinding and dividing step;
Extending the wafer on which the metal film coating step has been performed, and breaking the metal film along individual devices.
A method for processing a wafer.

Images