TWI591703B - Wafer processing methods - Google Patents

Description

Wafer processing method Field of invention

The present invention relates to a method of processing a wafer by dividing a wafer on which a component is formed on a surface of a substrate, and dividing the plurality of dicing streets for dividing the component.

Background of the invention

As is known to those skilled in the art, in a semiconductor device manufacturing process, a plurality of ICs, LSIs, and the like are formed in a matrix by a functional layer formed of a surface layer insulating film and a functional film of a substrate such as a germanium. Forming a semiconductor wafer. The semiconductor wafer thus formed is divided into the above-described elements by a predetermined dividing line called a dicing street, and is divided along the dicing street to form individual semiconductor elements.

Recently, in order to improve the processing capability of a semiconductor wafer such as an IC or an LSI, a semiconductor wafer in which a functional layer is formed on a surface layer of a substrate such as a substrate to form a semiconductor element is formed, and the functional film is formed of SiOF or BSG ( A low dielectric constant insulator film (Low-k film) composed of an inorganic film such as an inorganic film such as SiOB) or an organic film of a polymer film such as polyacrylonitrile or parylene.

In addition, a metal pattern formed by laminating a metal film called a test element group (TEG) is partially disposed on a dicing street of a semiconductor wafer, and the semiconductor crystal of the test element function is transmitted through the metal pattern before the semiconductor wafer is divided. circle.

A method of dividing a plate-shaped workpiece such as a semiconductor wafer described above may employ a laser processing method in which a pulsed laser beam having a wavelength penetrating the object to be processed is used to concentrate the condensed spot on the region to be divided. The interior is illuminated with pulsed laser light. The segmentation method using the laser processing method is a pulsed laser beam in which a light-converging point is concentrated on one side of a workpiece and irradiated with a wavelength penetrating the object to be processed, and a cutting path is formed inside the workpiece. The modified layer is continuously formed, and an external force is applied along the scribe line in which the strength is lowered by forming the modified layer, thereby dividing the workpiece (see Patent Document 1 as an example).

However, even if a laser processing method is used, a wafer having a low dielectric constant insulator film (Low-k film) on a substrate surface layer or a metal film called a test element group (TEG) is laminated. The metal pattern of the wafer is divided and cannot be surely divided along the scribe line. That is, even if the condensed spot is concentrated on the inside of the substrate from one side of the wafer and irradiates the pulsed laser light having a wavelength penetrating the substrate, the modified layer is formed along the scribe line inside the substrate, and the external force is applied along the scribe line. It is also impossible to reliably cut off a functional layer such as a low dielectric constant insulator film (Low-k film) or a metal film. Moreover, even if the wafer is cut along the scribe line, the organic energy layer is peeled off so that the quality of each of the divided components is lowered.

In order to solve the problem, the following Patent Document 2 discloses a wafer. The method of dividing is to discharge the functional layer along the scribe line by laser light illuminating the functional layer of the substrate along the scribe line to illuminate the functional layer, and to illuminate the substrate along the etched surface along the back side of the substrate. After the laser beam of the wavelength of the transparency forms a modified layer along the scribe line inside the substrate, an external force is applied to the wafer on which the modified layer is formed, and the wafer is divided along the scribe line.

Advance technical file Patent literature

[Patent Document] Japanese Patent License No. 3408805

[Patent Document] Japanese Patent Laid-Open Publication No. 2007-173474

Summary of invention

However, in the method of dividing a wafer according to the above Patent Document 2, the laser light having a wavelength absorbing to the functional layer laminated on the substrate is irradiated along the dicing street to break the functional layer along the scribe line, so that the substrate is also Laser processing is applied along the cutting path. Therefore, the outer peripheral edge of the surface side of the substrate which has been formed along the cutting path is melted and resolidified by laser processing, and the bending strength of the element is lowered.

The present invention has been made in view of the above facts, and the main technical object thereof is to provide a method for processing a wafer by forming a wafer of components by a functional layer laminated on a surface of a substrate without bending the component. In the lowered state, the cutting path is indeed divided.

In order to solve the above main technical problems, it is provided according to the present invention. A method for processing a wafer by dividing a wafer formed with a functional layer laminated on a surface of a substrate along a plurality of dicing streets for dividing the component; the method for processing the wafer includes the following procedure: The trench forming process is to irradiate a laser beam having a wavelength absorbing to the functional layer from the surface of the wafer along the scribe line formed on the wafer, and form a scribe groove on the functional layer that does not reach the substrate along the scribe line; Forming a process by irradiating a laser beam having a wavelength that is transparent to a substrate of the wafer along a scribe line on the back side of the wafer, forming a modified layer along the scribe line inside the substrate; and dividing the program to form a modified layer The wafer of the layer imparts an external force to divide the wafer along the scribe line.

After the scribe groove forming process is performed, a protective member is attached to the surface of the wafer, and the modified layer forming process is performed. The dividing process holds the protective member side of the wafer by the holding means, and rotates the grinding wheel and presses it. The back surface of the substrate is ground, and the substrate is formed into a predetermined thickness and divided along the scribe line in which the modified layer is formed.

Moreover, the modified layer forming process is performed before the execution of the scribe groove forming process, and includes a wafer supporting program for forming a modified layer along the scribe line in the substrate by performing a modified layer forming process. The back side of the wafer is attached to the surface of the dicing tape mounted on the annular frame; the scribe line forming process is performed on the wafer attached to the surface of the dicing tape mounted on the annular frame; The dicing tape attached to the wafer is expanded to apply a tensile force to the wafer to divide the wafer along the scribe line.

In the method for processing a wafer according to the present invention, a scribe line forming process is performed to form a scribe line that does not reach the substrate along the dicing line in the functional layer, and a modified layer forming process is performed to form a modified layer along the scribe line inside the substrate. Thereafter, an external force is applied to the wafer on which the modified layer is formed to divide the wafer along the scribe line, so that the wafer can be surely divided along the scribe line.

Further, since the scribe line formed in the functional layer by the scribe groove forming process is formed in a range that does not reach the substrate, the substrate is not subjected to laser processing. Therefore, the outer peripheral edge of the surface side of the element which has been divided along the cutting path does not form a state of being melted and resolidified by laser processing, so that the bending strength of the element is not lowered.

2‧‧‧Semiconductor wafer

2a‧‧‧ surface

2b‧‧‧back

20‧‧‧Substrate

21‧‧‧ functional layer

22‧‧‧ components

23‧‧‧ cutting road

24‧‧‧ditch

25‧‧‧Modified layer

3‧‧‧ Laser processing equipment

30‧‧‧ Laser processing equipment

31‧‧‧The chuck holder for laser processing equipment

32‧‧‧Laser light exposure

321‧‧‧Shell

322‧‧‧ concentrator

33‧‧‧Photography

4‧‧‧Protection components

5‧‧‧ grinding device

51‧‧‧Clamping device chuck

51a‧‧‧ arrow direction

52‧‧‧ grinding means

521‧‧‧Heart sleeve

522‧‧‧Rotating mandrel

523‧‧‧Accessories

524‧‧‧ grinding wheel

524a‧‧‧ arrow direction

524b‧‧‧ arrow direction

525‧‧‧Abutment

526‧‧‧ grinding wheel

527‧‧‧ fastening bolts

6‧‧‧Ring frame

7‧‧‧Cut tape

8‧‧‧Splitting device

81‧‧‧Frame keeping means

811‧‧‧Frame holding members

811a‧‧‧Loading surface

812‧‧‧ fixture

82‧‧‧ Tape expansion means

821‧‧‧Expanding drum

822‧‧‧Support flange

83‧‧‧Support means

831‧‧ ‧ cylinder

832‧‧‧ piston rod

Spotlight of P‧‧‧pulse laser light

X1‧‧‧ arrow direction

1(a) to 1(b) are a perspective view and a partially enlarged cross-sectional view showing a semiconductor wafer divided by the wafer processing method of the present invention.

Fig. 2 is a perspective view showing a principal part of a laser processing apparatus for carrying out a scribe groove forming process in the method for processing a wafer of the present invention.

3(a) to 3(c) are explanatory views showing a procedure for forming a scribe groove in the method for processing a wafer of the present invention by the laser processing apparatus shown in Fig. 2.

4(a) to 4(b) are explanatory views of a protective member attaching procedure in the method of processing a wafer of the present invention.

Fig. 5 is a perspective view showing the main part of a laser processing apparatus for carrying out a reforming layer forming process in the method for processing a wafer of the present invention.

6(a) to 6(c) are explanatory views showing a procedure for forming a reforming layer in the method for processing a wafer of the present invention by using the laser processing apparatus shown in Fig. 2.

Figure 7 is a cross-sectional view of a method for processing a wafer for carrying out the present invention. A perspective view of the main part of the grinding device of the back grinding program of the program.

8(a) to 8(b) are explanatory views showing a back grinding process having a division program in the method of processing a wafer of the present invention by the grinding apparatus shown in Fig. 7.

9(a) to 9(b) are explanatory views of a wafer supporting program in the method of processing a wafer of the present invention.

Fig. 10 (a) to (c) are explanatory views showing another embodiment of the reforming layer forming program in the method for processing a wafer of the present invention.

Fig. 11 is an explanatory view showing a dividing device for performing a dividing program in the method for processing a wafer of the present invention.

12(a) to 12(b) are explanatory views showing a division procedure in the method of processing a wafer of the present invention by using the dividing device shown in Fig. 11.

Form for implementing the invention

Hereinafter, the processing method of the wafer of the present invention will be described in further detail with reference to the accompanying drawings.

1(a) and (b) are a perspective view and a main enlarged cross-sectional view of a semiconductor wafer divided into individual components by the wafer processing method of the present invention. The semiconductor wafer 2 shown in (a) and (b) of FIG. 1 is formed by a plurality of ICs and LSIs in which a surface layer insulating film of a substrate 20 and a functional film for forming a circuit constitute a functional layer 21 and formed in a matrix. Element 22. Further, each element 22 is divided by a scribe line 23 formed in a lattice shape. Further, in the illustrated embodiment, the insulating film forming the functional layer 21 is made of a SiO2 film or a low dielectric constant insulator film (Low-k film), and the low dielectric constant insulator film (Low-k film) It is made of inorganic film or polyimine such as SiOF or BSG (SiOB). An organic film system composed of a polymer film such as parylene or the like. Further, in the present specification, the functional layer is set to include a metal film disposed on the scribe line.

A first embodiment in which the semiconductor wafer 2 is divided along the dicing street 23 will be described with reference to Figs. 2 to 8 .

In the first embodiment, first, a scribe groove forming process is performed to irradiate a laser beam having a wavelength absorbing to the functional layer 21 from the surface side of the semiconductor wafer 2 along the scribe line 23 of the semiconductor wafer 2 to the functional layer 21 A scribe line that does not reach the substrate 20 is formed along the scribe line 23. This scribe groove forming program is implemented by the laser processing apparatus 3 shown in Fig. 2 . The laser processing apparatus 3 shown in FIG. 2 is provided with a chuck table 31 for holding a workpiece, and a laser beam for irradiating a laser beam to a workpiece held on the chuck holder 31. The means 32, and a photographing means 33 for photographing the workpiece held on the collet holder 31. The chuck holder 31 is configured to attract and hold a workpiece, and is movable by a moving mechanism (not shown) to a machining feed direction indicated by an arrow X in FIG. 2 and an index feed direction indicated by an arrow Y.

The laser light irradiation means 32 includes a cylindrical outer casing 321 which is disposed substantially horizontally. A pulsed laser ray oscillating means (not shown) is disposed in the casing 321 and is provided with a pulsed laser ray oscillator or a repetition frequency setting means composed of a YAG laser oscillator or a YVO4 laser oscillator. The front end of the outer casing 321 is provided with a concentrator 322 for collecting the pulsed laser light oscillated by the pulsed laser oscillating means.

The photographing means 33 attached to the front end portion of the outer casing 321 constituting the laser beam irradiation means 32 is visible light in addition to the illustrated embodiment. An infrared illuminating means for illuminating a workpiece with infrared rays, an optical system for capturing infrared rays irradiated by the infrared illuminating means, and an infrared ray captured by the optical system, in addition to a general photographic element (CCD) for photographing The imaging element (infrared CCD) of the corresponding electrical signal is configured, and the captured video signal is transmitted to a control means not shown.

A scribe groove forming process performed by the above-described laser processing apparatus 3 will be described with reference to Figs. 2 and 3 .

In the scribe groove forming process, the semiconductor wafer 2 is first placed on the chuck holder 31 of the laser processing apparatus 3 shown in FIG. 2, and the semiconductor wafer 2 is adsorbed and held on the chuck holder 31. The semiconductor wafer 2 is in a state in which the surface 2a is kept on the upper side.

The chuck holder 31 that holds and holds the semiconductor wafer 2 as described above is positioned directly below the photographing means 33 by a processing feed mechanism (not shown). Once the chuck holder 31 is positioned directly below the photographing means 33, the photographing means 33 and a control means not shown are used to perform a calibration operation to detect the processing area of the semiconductor wafer 2 to be subjected to laser processing. In other words, the photographing means 33 and the control means (not shown) perform image processing such as pattern matching for performing the dicing street 23 formed in the predetermined direction of the semiconductor wafer 2 and the laser beam irradiating the laser beam along the dicing street 23. The illuminator 322 of the light illuminating means 32 is aligned and the calibration of the position of the laser beam illumination is performed. Further, for the dicing streets 23 formed on the semiconductor wafer 2 and extending in a direction orthogonal to the predetermined direction, the calibration of the laser beam irradiation position is also performed.

As described above, the semiconductor wafer 2 held on the chuck holder 31 is detected by the dicing street 23 formed thereon, and the laser light irradiation position is calibrated. Thereafter, as shown in FIG. 3, the collet holder 31 is moved to a laser beam irradiation region where the concentrator 322 of the laser beam irradiation means 32 for irradiating the laser beam is irradiated, and the predetermined dicing street 23 is to be formed. Positioned directly below the concentrator 322. At this time, as shown in FIG. 3(a), the semiconductor wafer 2 is positioned such that one end of the dicing street 23 (the left end in FIG. 3(a)) is located immediately below the concentrator 322. Next, the concentrator 322 of the laser beam irradiation means 32 illuminates the pulsed laser light having a wavelength absorbing to the functional layer 21 of the semiconductor wafer 2, and the chuck holder 31, that is, the semiconductor wafer 2 is as shown in FIG. (a) The direction indicated by the arrow X1 is moved at a predetermined machining feed speed. Next, as shown in FIG. 3(b), when the other end of the dicing street 23 (the right end in FIG. 3(b)) reaches the position directly below the concentrator 322, the irradiation of the pulsed laser light is stopped and the movement of the chuck holder 31 is stopped. That is, the semiconductor wafer 2. In the scribe groove forming process, the condensed spot P of the pulsed laser light falls near the surface of the scribe line 23.

By performing the above-described scribe groove forming process, as shown in FIGS. 3(b) and (c), the scribe line 24 that does not reach the substrate 20 can be formed along the dicing street 23 in the functional layer 21. The scribe line forming process is performed one by one along all of the dicing streets 23 formed on the semiconductor wafer 2.

Further, the above-described scribe groove forming program is exemplified by the following processing conditions.

Light source of laser light: LD excitation Q switch Nd: YVO4 laser

Wavelength: 355nm

Repeat frequency: 200kHz

Output: 1W

Converging point diameter: Φ6μm

Processing feed rate: 200mm / sec

The vertices 24 having a width of 1 to 3 μm and a depth of 1 to 2 μm can be formed along the dicing street 23 in accordance with the apex of the output distribution formed by the Gaussian distribution of the pulsed laser light irradiated under the above-described processing conditions.

After the above-described scribe groove forming process is performed, the protective member 4 (protective member attaching program) for protecting the element 22 is attached to the surface of the semiconductor wafer 2 as shown in FIGS. 4(a) and 4(b).

Next, the reforming layer forming process is performed by irradiating the laser beam penetrating the substrate 20 of the semiconductor wafer 2 along the dicing street 23 on the side of the back surface 2b of the substrate 20, and forming a modification along the dicing street 23 inside the substrate 20. Floor. This modified layer forming program is implemented by the laser processing apparatus 30 shown in Fig. 5, and the laser processing apparatus 30 is substantially the same as the laser processing apparatus 30 shown in Fig. 2 described above. The laser processing device 30 is substantially the same as the laser processing device 3, and the same members are designated by the same reference numerals, and their description will be omitted.

When the reforming layer forming process is performed by the above-described laser processing apparatus 30, the side of the protective member 4 attached to the surface 2a of the semiconductor wafer 2 is placed on the chuck holder 31 of the laser processing apparatus 30 shown in FIG. The semiconductor wafer 2 is adsorbed and held by the chuck holder 31 by suction means not shown. Therefore, the semiconductor wafer 2 held by the chuck holder 31 is attracted to the upper side of the back surface 2b. In this way, the chuck holder 31 holding the semiconductor wafer 2 can be attracted to the photographing means 33 by a moving mechanism (not shown).

Once the collet holder 31 is positioned directly below the photographing means 33, the photographing means 33 and the control means not shown are used to perform the calibration work to detect A processing area of the semiconductor wafer 2 that should be subjected to laser processing. This calibration operation is substantially the same as the calibration operation of the scribe groove forming program. In the calibration operation, the surface 2a of the semiconductor wafer 2 on which the dicing street 23 is formed is located on the lower side, but the photographic means 33 is further provided with an infrared illuminating means and an optical system for capturing infrared rays. Since the imaging means including the imaging element (infrared CCD) corresponding to the electrical signal of the infrared ray is output, the scribe line 23 can be penetrated by the back surface 2b.

After the dicing street 23 formed by the semiconductor wafer 2 held on the chuck holder 31 is detected as described above and the laser light irradiation position is calibrated, the chuck holder 31 is as shown in FIG. 6(a). Moving to a laser light irradiation area where the concentrator 322 of the laser light irradiation means 32 for irradiating the laser light is located, and positioning one end of the predetermined cut track 23 (left end in Fig. 6(a)) The concentrator 322 of the laser light illuminating means 32 is directly below. Next, the pulsed laser light having a wavelength penetrating the substrate 20 is irradiated by the concentrator 322, and the chuck holder is moved at a predetermined feed speed in the direction indicated by an arrow X1 in Fig. 6(a). Next, as shown in Fig. 6(b), when the irradiation position of the concentrator 322 reaches the position of the other end of the dicing street 23, the irradiation of the pulsed laser light is stopped and the movement of the chuck holder 31 is stopped. In the reforming layer forming process, the condensed spot P of the pulsed laser light falls inside the semiconductor wafer 2, thereby being able to be inside the semiconductor wafer 2 as shown in FIGS. 6(b) and (c). The dicing street 23 forms a modified layer 25. The reforming layer forming process is performed one by one along all of the dicing streets 23 formed on the semiconductor wafer 2.

The processing conditions of the above-described modified layer forming program are set as follows in the following examples.

Light source: LD excitation Q switch Nd: YVO4 laser

Wavelength: 1064nm

Repeat frequency: 100kHz

Output: 0.2W

Convergence point diameter: Φ1μm

Processing feed rate: 200mm / sec

After the reforming layer forming process is carried out, a dividing process is performed, an external force is applied to the semiconductor wafer 2 on which the modified layer 25 is formed, and the semiconductor wafer 2 is divided along the dicing street 23. The dividing process is achieved by a back grinding process in which the protective member 4 side of the semiconductor wafer 2 is held by a holding means, and the grinding wheel is rotated and pressed against the back surface of the substrate 20 for grinding. The substrate 20 is formed to a predetermined thickness and divided along the dicing streets 23 on which the modified layer is formed. The back grinding process which also serves as the division program is carried out using the grinding device 5 shown in Fig. 7 . The grinding device 5 shown in Fig. 7 is provided with a chuck holder 51 as a holding means for holding a workpiece, and a grinding means 52 for grinding a workpiece held on the chuck holder 51. The chuck base 51 is configured to suck and hold the workpiece thereon, and is rotatable in a direction indicated by an arrow 51a in Fig. 7 by a rotation drive mechanism (not shown). The grinding means 52 is provided with a mandrel sleeve 521, a rotating mandrel 522 which is rotatably supported in the mandrel sleeve 521 and which is driven to rotate via a rotary drive mechanism, and a mounting shaft mounted on the lower end of the rotary mandrel 522. A fitting 523 and a grinding wheel 524 mounted under the fitting 523. The grinding wheel 524 is composed of a ring-shaped base 525 and a grinding wheel 526 which is annularly mounted under the base 525, and the base 525 is mounted on the fitting by fastening bolts 527. Below 523.

When the grinding process is performed by the above-described grinding device 5, the protective member 4 side of the semiconductor wafer 2 is placed on the upper surface (holding surface) of the chuck holder 51 as shown in FIG. Then, the semiconductor wafer 2 is sucked and held by the protective member 4 via the suction means (not shown) on the chuck holder 51 (wafer holding program). Therefore, the semiconductor wafer 2 held by the chuck holder 51 is sucked through the protective member 4, and the back surface 2b is placed on the upper side. After the semiconductor wafer 2 is sucked and held by the protective member 4 on the chuck holder 51 as described above, the chuck holder 51 is rotated in a direction indicated by an arrow 51a in FIG. 7 at a number of revolutions of, for example, 600 rpm, and the grinding means is provided. The grinding wheel 524 of 52 rotates at a number of revolutions of, for example, 3000 rpm in the direction indicated by an arrow 524a in Fig. 7, and the grinding wheel 526 is brought into contact with the working surface, that is, the semiconductor constituting the semiconductor wafer 2, as shown in Fig. 8(a). The back surface 2b of the substrate 20, and the grinding wheel 524 is turned downward at a grinding feed speed of, for example, 1 μm/sec as shown by an arrow 524b in Figs. 7 and 8(a) (relative to the holding surface of the chuck holder 51). In the vertical direction, the feed is ground for a predetermined amount (back grinding program). As a result, the back surface 2b of the semiconductor substrate 20 constituting the semiconductor wafer 2 is ground, and the semiconductor wafer 2 is formed to have a predetermined thickness (for example, 100 μm) as shown in FIGS. 8(a) and (b), and the thinned semiconductor The wafer 2 can be divided into individual elements 22 along a dicing street 23 formed with a modified layer 25 and reduced in strength. At this time, the functional layer 21 in which the element 22 is formed on the surface of the semiconductor substrate 20 is formed with the scribe line 24 along the dicing street 23, so that the functional layer 21 can also be divided along the scribe line 23. Further, since the scribe groove 24 is formed on the functional layer 21 within the range of not reaching the substrate 20 as described above, the substrate 20 is not subjected to laser processing. Therefore, as described above, the outer peripheral edge of the surface side of the element 22 which has been divided along the cutting path 23 does not form a state of being melted and resolidified by laser processing, so that the bending strength of the element 22 is not lowered.

Next, a second embodiment in which the semiconductor wafer 2 is divided along the dicing street 23 will be described. In the second embodiment, the semiconductor wafer 2 is grounded on the back surface of the semiconductor substrate 20 in advance to form a predetermined thickness (for example, 100 μm).

In the second embodiment, the modified layer forming program is carried out before the execution of the scribe groove forming process. The modified layer forming procedure can be carried out in the same manner as the modified layer forming procedure shown in Figs. 5 and 6 described above. In addition, the modified layer forming procedure illustrated in FIGS. 5 and 6 is performed in a state in which a protective member is attached to the surface of the semiconductor wafer 2, but a protective member may not be attached to the surface of the semiconductor wafer 2. Implement a modified layer formation procedure.

After performing the reforming layer forming process, the wafer supporting process is performed, and the back surface of the semiconductor wafer 2 having the modified layer formed along the dicing street 23 inside the semiconductor substrate 20 is attached to the dicing tape mounted on the annular frame. surface. In other words, as shown in FIGS. 9(a) and 9(b), the back surface 2b side of the semiconductor wafer 2 is attached to a dicing tape 7 which is provided on the annular frame 6 and is made of a synthetic resin sheet such as polyolefin. surface. Therefore, the semiconductor wafer 2 attached to the surface of the dicing tape 7 is in a state in which the surface 2a is formed on the upper side.

Next, the scribe groove forming process is performed, and the dicing street 23 of the semiconductor wafer 2 attached to the surface of the dicing tape 7 mounted on the annular frame 6 is irradiated to the functional layer 21 by the surface side of the semiconductor wafer 2. The laser light of the absorptive wavelength forms a scribe line on the functional layer 21 along the scribe line 23 that does not reach the semiconductor substrate 20. This scribe groove forming program is implemented by the above-described laser processing apparatus 3 shown in Fig. 2 . That is, the side of the dicing tape 7 to which the semiconductor wafer 2 is attached is placed on the chuck holder 31 of the laser processing apparatus 3 shown in FIG. The bulk wafer 2 is adsorbed and held on the chuck holder 31 via a slit tape 7. Therefore, the semiconductor wafer 2 held on the chuck holder 31 is in a state in which the surface 2a is formed on the upper side. Further, the annular frame 6 on which the dicing tape 7 is attached is fixed to the cradle holder 31 by a jig (not shown).

The chuck holder 31 that holds and holds the semiconductor wafer 2 as described above is positioned directly below the photographing means 33 by a processing feed mechanism (not shown). Once the chuck holder 31 is positioned directly below the photographing means 33, the calibration operation is performed by the photographing means 33 and a control means not shown to detect the processing area of the semiconductor wafer 2 to be subjected to laser processing.

Next, as shown in FIG. 10(a), the chuck holder 31 is moved to a laser beam irradiation area where the concentrator 322 of the laser beam irradiation means 32 for irradiating the laser light is irradiated, and the predetermined cutting is performed. The track 23 is positioned directly below the concentrator 322. Subsequently, a scribe groove forming process is carried out in the same manner as in the embodiment shown in Fig. 3 described above. As a result, as shown in FIGS. 10(b) and (c), the scribe line 24 which does not reach the substrate 20 is formed along the dicing street 23 in the functional layer 21. The scribe line forming process is performed one by one along all of the dicing streets 23 formed on the semiconductor wafer 2.

After the scribing groove forming process is carried out, the dividing process is performed to apply an external force to the semiconductor wafer 2 on which the modified layer 25 is formed, and the semiconductor wafer 2 is divided along the dicing street 23. This division program is implemented by the division device 8 shown in Fig. 11 in the illustrated embodiment. The dividing device 8 shown in Fig. 11 is provided with a frame holding means 81 for holding the annular frame 6, and a dicing tape for attaching to the annular frame 6 held by the frame holding means 81. 7 expanded tape expansion means 82. The frame holding means 81 is composed of an annular frame holding member 811 and a plurality of frames arranged in the frame. The outer periphery of the member 811 is constituted by a jig 812 as a fixing means. A mounting surface 811a on which the annular frame 6 is placed is formed on the upper surface of the frame holding member 811, and the annular frame 6 can be placed on the mounting surface 811a. The annular frame 6 placed on the mounting surface 811a is fixed to the frame holding member 811 by a jig 812. The frame holding means 81 constructed as described above is supported by the tape expanding means 82 and is in a state in which it can advance and retreat in the up and down direction.

The tape expanding means 82 includes an expanding drum 821 disposed inside the annular frame holding member 811. The inner diameter of the expansion drum 821 is smaller than the inner diameter of the annular frame 6, and the outer diameter is larger than the outer diameter of the semiconductor wafer 2 to which the dicing tape 7 attached to the annular frame 6 is attached. Further, the expansion drum 821 is provided with a support flange 822 at the lower end. The tape expanding means 82 of the embodiment shown in the figure is provided with a supporting means 83 for allowing the annular frame holding member 811 to advance and retreat in the vertical direction. The support means 83 is composed of a plurality of cylinders 831 disposed on the support flange 822, and the piston rod 832 is coupled to the lower surface of the annular frame holding member 811. As described above, the support means 83 composed of the plurality of cylinders 831 has the annular frame holding member 811 at a reference position at which the mounting surface 811a and the upper end of the expansion drum 821 are approximately at the same height, and the mounting surface 811a is lower than the expansion drum. The upper end of the wheel 821 moves in a vertical direction between a predetermined amount of expansion positions. Therefore, the supporting means 83 composed of the plurality of cylinders 831 can function as an expanding moving means for relatively moving the expanding drum 821 and the frame holding member 811 in the vertical direction.

The division procedure performed by the division device 8 having the above configuration will be described with reference to FIG. That is, the ring in which the semiconductor wafer 2 (the scribe line 24 and the modified layer 25 are formed along the scribe line 23) is supported by the dicing tape 7 The frame 6 is placed on the mounting surface 811a of the frame holding member 811 constituting the frame holding means 81 as shown in Fig. 12(a), and is fixed to the frame holding member 811 by a clamp mechanism 812. At this time, the frame holding member 811 is positioned at the reference position shown in FIG. 12(a). Next, the plurality of cylinders 831 as the supporting means 83 constituting the tape expanding means 82 are activated, and the annular frame holding member 811 is lowered to the expanded position shown in Fig. 12 (b). Therefore, the annular frame 6 fixed to the mounting surface 811a of the frame holding member 811 is also lowered, so that the cutting tape 7 attached to the annular frame 6 directly contacts the expansion drum as shown in Fig. 12(b). The upper edge of 821 is expanded and expanded (tape expansion procedure). As a result, a radial tensile force is generated to the semiconductor wafer 2 attached to the dicing tape 7. Once the radial tensile force is applied to the semiconductor wafer 2 as described, the intensity of the modified layer 25 formed along the scribe line 23 is lowered, and the modified layer 25 becomes the starting point of the division, and the semiconductor wafer can be formed. The substrate 20 of 2 is cut along the dicing streets 23 on which the reforming layer 25 is formed and divided into individual elements 22. At this time, the function layer 21 which is formed by laminating the elements on the surface of the substrate 20 is formed with the scribe grooves 24 along the dicing streets 23, so that the functional layer 21 can also be divided along the dicing streets 23. Further, since the scribe groove 24 is formed on the functional layer 21 within the range of the substrate 20 as described above, the substrate 20 is not subjected to laser processing. Therefore, as described above, the outer peripheral edge of the surface side of the element 22 which has been divided along the cutting path 23 does not form a state of being melted and resolidified by laser processing, so that the bending strength of the element 22 is not lowered.

2‧‧‧Semiconductor wafer

2a‧‧‧ surface

2b‧‧‧back

20‧‧‧Substrate

21‧‧‧ functional layer

22‧‧‧ components

23‧‧‧ cutting road

24‧‧‧ditch

31‧‧‧The chuck holder for laser processing equipment

32‧‧‧Laser light exposure

322‧‧‧ concentrator

Spotlight of P‧‧‧pulse laser light

X1‧‧‧ arrow direction

Claims (3)

A method for processing a wafer by dividing a wafer formed with a functional layer laminated on a surface of a substrate along a plurality of dicing streets for dividing the component; the method for processing the wafer includes the following procedure: The trench forming process is to irradiate a laser beam having a wavelength absorbing to the functional layer from the surface of the wafer along the scribe line formed on the wafer, and form a scribe groove on the functional layer that does not reach the substrate along the scribe line; Forming a process by irradiating a laser beam having a wavelength that is transparent to a substrate of the wafer along a scribe line on the back side of the wafer, forming a modified layer along the scribe line inside the substrate; and dividing the program to form the modified The wafer of the quality layer imparts an external force to divide the wafer along the scribe line. The method for processing a wafer according to claim 1, wherein the modifying layer forming process is performed by attaching a protective member to the surface of the wafer after the groove forming process is performed; the dividing program is maintained by holding means The protective member side of the wafer is rotated and the grinding wheel is rotated and pressed against the back surface of the substrate to be ground, and the substrate is formed into a predetermined thickness and divided along the scribe line in which the modified layer is formed. The method for processing a wafer according to claim 1, wherein the reforming layer forming process is performed before the scribe forming process is performed, and the processing method includes a wafer supporting program, which is implemented by The reforming layer forming process is performed on the back of the wafer on which the modified layer is formed along the scribe line inside the substrate a surface attached to a surface of a dicing tape mounted on an annular frame; the scribe line forming process is performed on a wafer attached to a surface of a dicing tape mounted on the annular frame; The dicing tape attached to the wafer is expanded to apply a tensile force to the wafer to divide the wafer along the scribe line.