KR101418613B1 - Wafer dividing method - Google Patents

Abstract

An object of the present invention is to provide a wafer dividing method capable of dividing a wafer coated with a film on the surface of a street without leaving a film.

A wafer dividing method for dividing a wafer in which a device is formed in a plurality of regions partitioned by a plurality of streets formed in a lattice pattern on a surface of a substrate and a film is coated on the surface of the street into individual devices along the street, A step of dividing a film along a street by irradiating a laser beam of a wavelength having an absorbing property with respect to the film along a street from a surface side of the wafer and forming a laser machining groove and a step of dividing the film by a laser beam having a transmittance to the substrate, A modified layer forming step of irradiating the substrate with a light-converging point along the street from the back side of the wafer to form a modified layer along the streets in the substrate; grinding the back surface of the substrate constituting the wafer, A back grinding step of forming the wafer at a predetermined thickness; And breaking the wafer along the street.

Description

[0001] WAFER DIVIDING METHOD [0002]

The present invention relates to a wafer dividing method for dividing a wafer in which a plurality of streets are formed on a surface in a lattice shape and on which a device is formed in a plurality of regions partitioned by the plurality of streets along a street.

In a semiconductor device manufacturing process, a plurality of regions are defined by a line to be divided, which is called a street arranged on a surface of a semiconductor wafer which is substantially in the shape of a disk, and ICs, LSIs, liquid crystal drivers, Lt; / RTI > Then, the wafer is cut along the street to divide the area where the device is formed to manufacture individual devices.

As a method of dividing the wafer along the streets described above, there has also been attempted a laser machining method for irradiating a pulsed laser beam with a light-converging point inside a region to be divided by using a pulsed laser beam having a transmittance with respect to the wafer . In the dividing method using the laser processing method, a condensing point is set inward from one side of a wafer, a pulsed laser beam of a wavelength having a transmittance to the wafer is irradiated to continuously form a deteriorated layer along the streets in the wafer And the width of the street can be narrowed by dividing the wafer by splitting the wafer by applying an external force along the streets whose strength is decreased by forming the deformed layer (see, for example, Patent Document 1).

Patent Document 1: Japanese Patent No. 3408805

In a wafer in which a metal film, a fluorosilicate glass film, a silicon oxide film passivation film (SiO ₂ , SiON), a polyimide (PI) polymer compound film, a fluorine polymer compound film and a fluorinated amorphous carbon compound film are coated on the surface of a street, The wafer substrate can be divided by irradiating a pulsed laser beam of a wavelength having a transmittance to the wafer substrate with the light-converging point inside the wafer and forming a deteriorated layer along the streets in the wafer. However, There is a problem that the membrane can not be divided.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wafer dividing method capable of dividing a wafer coated with a film on the surface of a street without leaving a film.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a wafer on a surface of a substrate, the device being formed on a plurality of regions partitioned by a plurality of streets formed in a lattice pattern on a surface of the substrate, A method of dividing a wafer into individual devices along the street,

A film dividing step of dividing the film along the street by irradiating the film with a laser beam of a wavelength having an absorbency to the film from the surface side of the wafer along the street to form a laser processing groove,

A laser beam of a wavelength having a transmittance to the substrate is irradiated along the street from the back side of the wafer by positioning a light-converging point inside the substrate, and a denatured layer Forming process,

A back grinding step of grinding the back surface of the substrate constituting the wafer subjected to the altered layer forming step to form the wafer with a predetermined thickness;

An external force is applied to the wafer subjected to the backgrinding process, and a wafer breaking process for breaking the wafer along the street

The wafer dividing method is characterized in that the wafer dividing method is provided.

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a wafer on a surface of a substrate in which a device is formed in a plurality of regions partitioned by a plurality of streets formed in a lattice pattern on a surface of the substrate, As a wafer dividing method,

A film dividing step of dividing the film along the street by irradiating the film with a laser beam of a wavelength having an absorbency to the film from the surface side of the wafer along the street to form a laser processing groove,

A back grinding step of grinding the back surface of the substrate constituting the wafer subjected to the film dividing step to form the wafer to a predetermined thickness;

A laser beam of a wavelength having a transmittance to the substrate of the wafer subjected to the backgrinding process is irradiated along the street from the back side of the wafer by placing a light-converging point inside the substrate, A modified layer forming step of forming a denatured layer along the surface of the substrate,

An external force is applied to the wafer subjected to the denuded layer forming step to break the wafer along the street,

The wafer dividing method is characterized in that the wafer dividing method is provided.

In the wafer breaking step, an external force is applied to the wafer by expanding the dicing tape in a state in which the back surface of the wafer is adhered to the surface of the dicing tape mounted on the annular frame.

According to the method of dividing a wafer in the present invention, a film-dividing step of dividing a film coated on the surface of a street formed on a substrate of a wafer along a street, and a modified layer forming step of forming a damaged layer along a street in a substrate Thereafter, when an external force is applied to the wafer to break the wafer along the street, when the wafer is broken along the street, the film is divided along the street, so that the film is not broken and remains.

Hereinafter, preferred embodiments of the wafer dividing method according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a wafer divided by a wafer dividing method according to the present invention, and FIG. 2 is an enlarged cross-sectional view of a main portion of the wafer shown in FIG. The wafer 2 shown in Figs. 1 and 2 is formed by a plurality of streets 22 formed in a lattice shape on the surface 21a of a silicon substrate 21 having a thickness of, for example, 600 mu m, And devices 23 such as ICs, LSIs, liquid crystal drivers, and flash memories are formed in the divided areas. 2, a polyimide (PI) polymer compound film 24 is formed on the wafer 2 in the form of a coating 22 in the embodiment shown on the surface 21a including the street 22 and the device 23. [ .

A first embodiment of a wafer dividing method for dividing the above-described wafer 2 into individual devices 23 will be described.

In the first embodiment, a laser beam having a water absorption wavelength is applied to the polymer compound film 24 coated on the surface 21a of the substrate 21 constituting the wafer 2 from the surface side of the wafer 22 To the polymer compound film 24 to form laser-processed grooves, and a film dividing step for dividing the polymer compound film 24 along the streets is performed. This film dividing step is carried out by using the laser processing apparatus 3 shown in Fig. The laser machining apparatus 3 shown in Fig. 3 includes a chuck table 31 for holding a workpiece, a laser beam irradiating means 32 for irradiating the workpiece held on the chuck table 31 with a laser beam, And an image pickup means (33) for picking up a workpiece held on the chuck table (31). The chuck table 31 is configured to suck and hold the workpiece. The chuck table 31 is moved in the workpiece conveying direction indicated by an arrow X in FIG. 3 by a not-shown processing and feeding mechanism, And is moved in the indexing feed direction indicated by arrow Y.

The laser beam irradiating means 32 includes a cylindrical casing 321 arranged substantially horizontally. In the casing 321, there is provided a pulsed laser beam oscillation means having a pulse laser beam oscillator composed of a YAG laser oscillator or a YVO4 laser oscillator (not shown) and a repetition frequency setting means. A condenser 322 for condensing the pulsed laser beam emitted from the pulsed laser beam generating means is mounted on the distal end of the casing 321.

The imaging means 33 mounted on the distal end portion of the casing 321 constituting the laser beam irradiating means 32 includes an image pickup device CCD for picking up images by visible light and infrared rays for irradiating the workpiece with infrared rays An illumination system, an optical system for capturing infrared rays irradiated by the infrared illumination means, and an imaging device (infrared CCD) for outputting an electric signal corresponding to infrared rays captured by the optical system. The image pickup means (33) sends the picked up image signal to a control means (not shown).

The film dividing step performed using the above-described laser machining apparatus 3 will be described with reference to Figs. 3 to 5. Fig.

In the film dividing step, the back surface 21b side of the wafer 2 is placed on the chuck table 31 of the laser processing apparatus 3 shown in Fig. 3 described above. Then, the wafer 2 is held on the chuck table 31 by operating the suction means (not shown) (wafer holding step). Therefore, the surface 21a of the wafer 2 held on the chuck table 31 is on the upper side.

As described above, the chuck table 31 with the wafer 2 sucked and held is positioned directly under the image pickup means 33 by a not shown feed mechanism. When the chuck table 31 is located immediately below the imaging means 33, an alignment operation for detecting the machining area of the wafer 2 to be processed by the laser beam is performed by the imaging means 33 and control means not shown. The imaging means 33 and the control means not shown include a street 22 formed in a predetermined direction of the wafer 2 and a laser beam irradiating means 32 for irradiating a laser beam along the street 22, Such as pattern matching, for alignment with the condenser 322, and performs alignment of the laser beam irradiation position. In addition, alignment of the laser beam irradiation position is similarly performed on the streets 22 formed on the wafer 2 so as to extend at right angles to the predetermined direction (alignment step). Even if the polyimide (PI) based polymer film 24 coated on the surface 21a including the street 22 of the wafer 2 and the device 23 is not transparent, the alignment step 33) are provided with the imaging means composed of the infrared illumination means, the optical system for capturing the infrared rays, and the imaging element (infrared CCD) for outputting the electric signal corresponding to the infrared rays, It is possible to capture the street 22 through the compound film 24.

When the street 22 formed on the wafer 2 held on the chuck table 31 is detected and the alignment of the laser beam irradiation position is performed as described above, as shown in Fig. 4 (a) The chuck table 31 is moved to the laser beam irradiation area in which the condenser 322 of the laser beam irradiating means 32 for irradiating the laser beam is positioned so that the predetermined street 22 is located just below the condenser 322 . 4 (a), the semiconductor wafer 2 is positioned so that one end of the street 22 (left end in FIG. 4 (a)) is positioned directly below the condenser 322 do. Next, the chuck table 31 is irradiated with a pulsed laser beam of a wavelength having absorbency from the condenser 322 of the laser beam irradiating means 32 to the polymer compound film 24 of the wafer 2, a) in a direction indicated by an arrow X1 at a predetermined processing feed speed. When the other end of the street 22 (the right end in FIG. 4B) reaches the position immediately below the condenser 322 as shown in FIG. 4B, the irradiation of the pulsed laser beam is stopped The movement of the chuck table 31 is stopped. In this film dividing step, the light-converging point P of the pulsed laser beam is adjusted to the vicinity of the surface (upper surface) of the polymer compound film 24 coated on the surface of the wafer 2.

By performing the above-described film dividing step, a laser machining groove 240 reaching the substrate 21 along the street 22 is formed in the polymer compound film 24 as shown in Fig. As a result, the polymer compound film 24 coated on the street 22 is divided along the street 22 by the laser processing groove 240. In the film dividing step, the polymer compound film 24 is laser-processed but immediately sublimated. Since the substrate 21 made of silicon is not processed, generation of debris by laser machining is suppressed.

The film dividing step is performed under the following processing conditions, for example.

Laser beam source: LD excitation Q switch Nd: YVO4 laser

Wavelength: 355 nm

Average power: 1W

Pulse width: 40 ns

Repetition frequency: 50 kHz

Condensing spot diameter:? 5 占 퐉

Processing feed rate: 100 mm / sec

If the film dividing step described above is performed along all the streets 22 extending in a predetermined direction of the wafer 2 as described above, the chuck table 31 is rotated 90 degrees and the chuck table 31 is rotated at right angles to the predetermined direction The protective film dividing process described above is performed along each of the extended streets 22. [

A laser beam of a wavelength having a transmittance to the substrate 21 of the wafer 2 is irradiated onto the substrate 2 from the back side of the wafer 2 by positioning the light- (22) to carry out a modified layer forming process for forming a modified layer along the street (22) inside the substrate (21). 6 (a) and 6 (b), in order to protect the device 23 formed on the surface of the wafer 2, the wafer 2 A protective tape 4 made of vinyl chloride or the like is adhered to the surface 21a of the protective tape 4 (protective tape sticking step).

When the protective tape 4 is adhered to the surface 21a of the wafer 2 as described above, the laser beam of a wavelength having a transmittance to the substrate 21 of the wafer 2 is condensed on the inside of the substrate 21 A denudation layer forming step of forming a denuded layer along the street 22 inside the substrate 21 is carried out by placing the point and irradiating the wafer 22 from the back side of the wafer 2 along the street 22. This denuded layer forming step is carried out using the same laser processing apparatus 3 as the laser processing apparatus 3 shown in Fig. 3, as shown in Fig. Therefore, the respective constituent members of the laser machining apparatus 3 are denoted by the same reference numerals as those in Fig. 3. The laser beam irradiating means 32 is provided with a pulsed laser beam oscillating means for oscillating a pulsed laser beam having a wavelength (for example, 1064 nm) having transparency with respect to the substrate 21.

In order to carry out the altered layer forming process using the laser machining apparatus 3 shown in Fig. 7, it is necessary to carry out the process of forming a protective layer on the chuck table 31 as shown in Fig. 7, Put the tape 4 side up. Then, a suction means (not shown) is operated to hold the wafer 2 on the chuck table 31 through the protective tape 4 (wafer holding step). Therefore, the wafer 2 held on the chuck table 31 has the back surface 21b on the upper side. In this way, the chuck table 31 with the wafer 2 sucked and held is positioned directly below the image pickup means 33 by a not shown feed mechanism.

When the chuck table 31 is located immediately below the image pickup means 33, the machining area to be laser-machined on the wafer 2 is detected by the image pickup means 33 and control means not shown in the same manner as the protective film dividing step And an alignment process is performed. That is, the image pickup means 33 and the control means (not shown) are disposed in a street 22 formed on the wafer 2 and a condenser (not shown) of the laser beam irradiating means 32 for irradiating the laser beam along the street 22 322 in order to perform alignment of the laser beam irradiation position. When the alignment process is performed, the surface 21a of the wafer 2 on which the street 22 is formed is located at the lower side. However, as described above, the imaging means 33 is provided with the infrared illumination means and the optical system (Infrared ray CCD) for outputting an electric signal corresponding to the infrared rays, and the like. Therefore, it is possible to capture the street 22 through the back surface 21b.

8 (a), the chuck table 31 is moved to the position where the laser is to be machined by the laser (not shown) One end of the predetermined street 22 (in which the laser machining groove 240 is formed) is moved to the laser beam irradiation area where the condenser 322 of the laser beam irradiating means 32 for irradiating the light is located Is positioned directly under the light condenser 322 of the laser beam irradiating means 32. [ The chuck table 31 is rotated at a predetermined processing feed rate in the direction indicated by arrow X1 in FIG. 8 (a) while pulsed laser beams of wavelengths having transmittance are emitted from the condenser 322 to the silicon substrate 21 . When the irradiating position of the condenser 322 of the laser beam irradiating means 32 reaches the position of the other end of the street 22 (the right end in FIG. 8 (b)) as shown in FIG. 8 (b) , The irradiation of the pulsed laser beam is stopped and the movement of the chuck table 31 is stopped. In the denuded layer forming step, the light-converging point P of the pulsed laser beam is positioned in the middle portion in the thickness direction of the semiconductor wafer 2. As a result, the altered layer 210 is formed on the substrate 21 of the wafer 2 in the thickness direction intermediate portion along the street 22 as shown in Figs. 8 (b) and 9. 9, when the altered layer 210 is formed along the street 22 in the substrate 21 of the wafer 2 as described above, the surface 21a (21a) is formed on the substrate 21 from the altered layer 210, And a crack 211 is generated along the street 22 in the direction of the back surface 21b.

The processing conditions in the altered layer forming step are set, for example, as follows.

Light source: LD excitation Q switch Nd: YVO4 laser

Wavelength: pulse laser of 1064 nm

Average power: 1W

Pulse width: 40 ns

Repetition frequency: 100 kHz

Condensing spot diameter:? 1 占 퐉

Processing feed rate: 100 mm / sec

If the above-described alteration layer forming process is performed along all the streets 22 extending in a predetermined direction of the wafer 2 as described above, the chuck table 31 is rotated 90 degrees so that the chuck table 31 is rotated at right angles The above-described altered layer forming process is carried out along each street 22 extending to the uppermost layer.

The rear surface 21b of the substrate 21 constituting the wafer 2 is ground to perform a backgrinding process of forming the wafer 2 to a predetermined thickness. This backside grinding step is carried out using the grinding apparatus 5 shown in Fig. 10 (a). 10A includes a chuck table 51 for holding a workpiece and a grinding wheel 52 for grinding a workpiece held in the chuck table 51 And a grinding means (53). In order to perform the above-described back grinding process using the grinding apparatus 5, the protective tape 4 side of the wafer 2 is placed on the chuck table 51 and a suction means (not shown) 2 is held on the chuck table 51. Therefore, the wafer 2 held on the chuck table 51 has the back surface 21b on the upper side. When the wafer 2 is held on the chuck table 51 in this way, the chuck table 51 is rotated at 300 rpm in the direction indicated by the arrow 51a while the grinding wheel 52 of the grinding means 53 (For example, 100 (mm)) as shown in Fig. 10 (b) by grinding the semiconductor wafer 2 in contact with the back surface 2b of the semiconductor wafer 2 while rotating it in the direction indicated by the arrow 52a, Mu m). If the altered layer 210 formed in the altered layer forming step is formed at a position within 100 mu m from the surface 2a of the wafer 2, the denatured layer 210 is left after the back grinding process, Since the altered layer 210 formed in the altered layer forming step is formed on the back surface 2b side from the surface 2a of the wafer 2, for example, at a position of 100 占 퐉, The layer 210 is ground to a position where the layer 210 is formed, and the denuded layer 210 is removed. Therefore, a crack 211 formed along the street 22 is left on the substrate 21 of the wafer 2 as shown in FIG. 10 (b).

Next, an external force is applied to the wafer 2 subjected to the above-described back-ground grinding process, and a wafer breaking process is performed to break the wafer 2 along the street. 11, the back surface 21b of the substrate 21 of the wafer 2 is adhered to the surface of the dicing tape T mounted on the annular frame F. In this case, (Wafer holding step). Then, the protective tape 4 adhering to the surface 21a of the substrate 21 of the wafer 2 is peeled (protective tape peeling step).

If the wafer holding step and the protective tape peeling step are performed as described above, the wafer 2 on which the film dividing step and the altered layer forming step are performed, that is, the polymer compound film 24 is divided along the street 22 An external force is applied to the wafer 2 having the crack 211 along the street 22 inside the substrate 21 to perform a wafer breaking process of breaking the wafer 2 along the street 22. [ This wafer breaking step is carried out using the tape expanding device 6 shown in Fig. 12 in the illustrated embodiment. The tape expanding device 6 shown in Fig. 12 includes a frame holding means 61 for holding the annular frame F and a frame holding means 61 for holding the annular frame F held by the frame holding means 61 And a tape extending means 62 for extending the dicing tape T. The frame holding means 61 includes an annular frame holding member 611 and a plurality of clamps 612 as fixing means provided on the outer periphery of the frame holding member 611. [ An upper surface of the frame holding member 611 is provided with a mounting surface 611a on which an annular frame F is placed and an annular frame F is placed on the mounting surface 611a. The annular frame F placed on the loading surface 611a is fixed to the frame holding member 611 by the clamp 612. [ The frame holding means 61 constructed as described above is supported by the tape extending means 62 so as to be movable up and down.

The tape expanding means 62 is provided with an extension drum 621 provided inside the annular frame holding member 611. The extension drum 621 has an inner diameter and an outer diameter larger than the inner diameter of the annular frame F and larger than the outer diameter of the wafer 2 adhered to the dicing tape T mounted on the annular frame F have. The extension drum 621 is provided with a support flange 622 at the lower end thereof. The tape expanding means 62 in the illustrated embodiment is provided with a supporting means 63 that can move the annular frame holding member 611 in the vertical direction. The support means 63 is composed of a plurality of air cylinders 631 provided on the support flange 622 and the piston rod 632 is connected to the lower surface of the annular frame holding member 611. The supporting means 63 composed of the plurality of air cylinders 631 is configured such that the annular frame holding member 611 is positioned at a reference position where the mounting surface 611a is approximately flush with the upper end of the expansion drum 621, In the vertical direction between the extended positions below the upper end of the expansion drum 621 by a predetermined amount. The supporting means 63 composed of a plurality of air cylinders 631 functions as an extension moving means for relatively moving the extension drum 621 and the frame holding member 611 in the vertical direction.

The wafer breaking process performed using the tape expanding apparatus 6 configured as described above will be described with reference to FIG. In other words, the back surface 21b of the wafer 2 (crack 211 is formed on the substrate 21 along the street 22 and the polymeric compound film 24 is formed with the laser processing groove 240) The annular frame F on which the dicing tape T adhered is mounted is mounted on the mounting surface 611 of the frame holding member 611 constituting the frame holding means 61 as shown in Fig. 611a and secured to the frame holding member 611 by a clamp 612. [ At this time, the frame holding member 611 is located at the reference position shown in Fig. 13 (a). Next, a plurality of air cylinders 631 serving as the support means 63 constituting the tape expanding means 62 are operated to move the annular frame holding member 611 to the extended position shown in Fig. 13 (b) Descend. Therefore, the annular frame F fixed on the mounting surface 611a of the frame holding member 611 is also lowered. Therefore, as shown in Fig. 13 (b) The dicing tape T is extended in contact with the upper edge of the extension drum 621. [ As a result, tensile force acts radially on the wafer 2 adhered to the dicing tape T, so that the substrate 21 of the wafer 2 is prevented from being damaged by the cracks 211 ) And divided into individual devices 23, respectively. At this time, since the polymer compound film 24 coated on the surface of the substrate 21 of the wafer 2 is divided by the laser machining groove 240 formed along the street 22, There is no.

In the above-described embodiment, the back surface of the substrate 21 of the wafer 2 is ground by the back grinding step to remove the altered layer 210. The wafer 2 has cracks 211 formed on the substrate 21, As shown in FIG. Therefore, since the damaged layer 210 does not remain on the fractured surface of the individual divided devices 23, the SAW of the device 23 is improved.

Next, a second embodiment of the wafer dividing method according to the present invention will be described.

The polymer compound film 24 is irradiated with the laser beam of the wavelength having absorbency to the polymer compound film 24 along the street 22 from the surface side of the wafer to form the laser processing groove, A film dividing step of dividing the polymer compound film 24 along the streets is carried out. This film dividing step is performed in the same manner as the film dividing step in the first embodiment.

Next, a back surface grinding step is performed in which the back surface 21b of the substrate 21 constituting the wafer 2 subjected to the film dividing step is ground to form the wafer 2 to a predetermined thickness. 6 (a) and 6 (b), in order to protect the device 23 formed on the surface of the wafer 2, the surface 21a of the wafer 2 ) Is adhered to the protective tape 4 made of vinyl chloride or the like (protective tape sticking step).

The back side grinding step of the wafer 2 subjected to the above-described film dividing step is carried out in the same manner as the back side grinding step in the first embodiment by using the grinding apparatus 5 shown in Fig. 10 (a) do. As a result, as shown in Fig. 14, the wafer 2 is ground with the back surface 21b of the substrate 21 to be formed with a predetermined thickness (for example, 100 占 퐉).

A laser beam of a wavelength having a transmittance to the substrate 21 of the wafer 2 is placed on the inside of the substrate 21 and the light is focused on the street 22 from the back side of the wafer 2, To form a modified layer along the streets 22 inside the substrate 21, as shown in FIG. This denuded layer forming step is performed in the same manner as the denuding layer forming step shown in Fig. 8 using the laser processing apparatus 3 as shown in Fig. As a result, on the substrate 21 of the wafer 2 formed with a predetermined thickness (for example, 100 占 퐉) as shown in Fig. 15, the altered layer 210 is formed along the street 22 inside, A crack 211 is generated from the layer 210 in the direction of the surface 21a and the backside 21b.

Next, the wafer 2, i.e., the polymer compound film 24, which has been subjected to the altered layer forming step described above, is divided along the street 22 and further along the streets 22 inside the substrate 21, An external force is applied to the wafer 2 on which the wafer 2 is formed so as to break the wafer 2 along the street 22. 11, the back surface 21b of the substrate 21 of the wafer 2 is placed on the surface of the dicing tape T mounted on the annular frame F, (Wafer holding step). Then, the protective tape 4 adhering to the surface 21a of the substrate 21 constituting the wafer 2 is peeled (protection tape peeling step).

If the wafer holding process and the protective tape peeling process have been performed, an external force is applied to the wafer 2 to perform a wafer breaking process in which the wafer 2 is broken along the street 22. This wafer breaking step is performed in the same manner as the wafer breaking step shown in Fig. 13 using the tape expanding device 6 shown in Fig. 12 described above. As a result, the substrate 21 of the wafer 2 is broken along the streets 22 where the strength is lowered by forming the deformed layer 210 and the cracks 211, and is divided into the individual devices 23. At this time, since the polymer compound film 24 coated on the surface of the substrate 21 of the wafer 2 is divided by the laser machining groove 240 formed along the street 22 as described above, There is no case that does not remain.

1 is a perspective view of a wafer divided by a wafer dividing method according to the present invention;

Fig. 2 is an enlarged cross-sectional view showing a main part of the wafer shown in Fig. 1; Fig.

3 is a perspective view of a main portion of a laser processing apparatus for performing a film dividing step in a wafer dividing method according to the present invention.

4 is an explanatory diagram of a film dividing step in the first embodiment of the wafer dividing method according to the present invention.

Fig. 5 is an enlarged cross-sectional view showing a main part of a wafer subjected to the film dividing step shown in Fig. 4; Fig.

6 is an explanatory diagram showing a protective tape adhering step in the first embodiment of the wafer dividing method according to the present invention.

7 is a perspective view of a main portion of a laser processing apparatus for carrying out the altered layer forming step in the first embodiment of the wafer dividing method according to the present invention.

8 is an explanatory view showing the altered layer forming step in the first embodiment of the wafer dividing method according to the present invention.

Fig. 9 is an enlarged cross-sectional view showing a main portion of the wafer subjected to the altered layer forming step shown in Fig. 8; Fig.

10 is an explanatory view showing a back grinding step in the first embodiment of the wafer dividing method according to the present invention.

11 is an explanatory view showing the wafer holding process and the protective tape peeling process in the first embodiment of the wafer dividing method according to the present invention.

12 is a perspective view showing a tape expanding apparatus for carrying out a wafer breaking process in the wafer dividing method according to the present invention.

13 is an explanatory view showing a wafer breaking process in the wafer dividing method according to the present invention.

Fig. 14 is an enlarged cross-sectional view showing a main portion of a wafer subjected to a backgrinding process in a second embodiment of the wafer dividing method according to the present invention; Fig.

15 is an enlarged cross-sectional view showing a main part of a wafer subjected to the altered layer forming step in the second embodiment of the wafer dividing method according to the present invention.

(Explanation of Symbols)

2: wafer

21: substrate

210: denaturated layer

211: crack

22: Street

23: Device

24: Polymer compound film

240: laser machining groove

3: Laser processing equipment

31: Chuck table of laser processing apparatus

32: laser beam irradiation means

4: Protective tape

5: Grinding device

51: chuck table of the grinding apparatus

52: grinding stone

53: Grinding means

6: Tape Expansion Unit

61: Frame keeping means

62: tape extension means

F: Fancy frame

T: Dicing tape

Claims (4)

There is provided a wafer dividing method for dividing a wafer in which devices are formed in a plurality of regions partitioned by a plurality of streets formed in a lattice pattern on a surface of a substrate and a film is coated on the surface of the streets into individual devices along the streets , A film dividing step of dividing the film along the street by irradiating the film with a laser beam of a wavelength having an absorbency to the film from the surface side of the wafer along the street to form a laser processing groove, A laser beam having a transmittance to the substrate is irradiated along the street from the backside of the wafer by placing a light-converging point inside the substrate, A modified layer forming step of forming a modified layer on the side of the modified layer and generating cracks along the street from the altered layer toward the front side and the back side; A back grinding step of grinding the back surface of the substrate constituting the wafer subjected to the altered layer forming step to form a wafer with a predetermined thickness to remove the altered layer; An external force is applied to the wafer by extending the dicing tape in a state in which the back surface of the wafer subjected to the backgrinding process is adhered to the surface of the dicing tape mounted on the annular frame, Fracture process Wherein the wafer is divided into a plurality of regions. delete delete delete

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