TW201903880A - Manufacturing method of chips capable of dividing sheet-like workpiece into chips without using expansion sheet - Google Patents

Abstract

Provided is a method for manufacturing a wafer capable of producing a plurality of wafers by dividing a plate-like workpiece without using an expansion sheet. Including: a laser processing step of irradiating a laser beam having a wavelength penetrating to the object to be processed only along the predetermined division line on the wafer region, and forming a modified layer along the predetermined division line of the wafer region, and other The remaining area of the periphery is used as a reinforcing part where no modified layer is formed; and a dividing step of applying force to the object to be divided into individual wafers; in the dividing step, applying force to the object by heating and cooling Divided into individual wafers.

Description

Manufacturing method of wafer

The present invention relates to a method for manufacturing a wafer by dividing a plate-like workpiece into a plurality of wafers.

In order to divide a plate-shaped workpiece (workpiece) typified by a wafer into a plurality of wafers, it is known to condense a laser beam having a penetrating power into the inside of the workpiece to form a plurality of wafers. A method of reforming a layer (modified region) that is modified by photon absorption (see, for example, Patent Document 1). The modified layer is more brittle than other areas. Therefore, a modified layer is formed along a predetermined dividing line (street; cutting path), and then a force is applied to the processed object, so that the modified layer can be processed as a starting point. The object is divided into a plurality of wafers.

When a force is applied to the object to be formed with the modified layer, for example, a method in which a stretchable expansion sheet (expansion tape) is attached to the object to be expanded is applied (for example, refer to Patent Document 2). In this method, before the laser beam is irradiated to form a modified layer on the workpiece, an expansion sheet is attached to the workpiece, and then a modified layer is formed, and then the expansion sheet is expanded to divide the workpiece into A plurality of wafers. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-192370 [Patent Document 2] Japanese Patent Laid-Open No. 2010-206136

[Problems to be solved by the invention]

However, in the method for expanding the expansion sheet as described above, the expansion sheet after use cannot be used again, so the cost required for manufacturing the wafer tends to be high. In particular, a high-performance expansion sheet in which an adhesive material is difficult to remain on a wafer, and its price is also high. Therefore, if such an expansion sheet is used, the cost required for manufacturing the wafer also becomes high.

The present invention has been made in view of this problem, and an object of the present invention is to provide a manufacturing method of a wafer that can divide a plate-like workpiece into a plurality of wafers without using an expansion sheet. [Technical means to solve the problem]

According to one aspect of the present invention, there is provided a method for manufacturing a wafer from a wafer region having a plurality of regions that are separated as a wafer by a plurality of intersecting predetermined division lines, and a remainder surrounding the wafer region. A method for manufacturing a wafer having a plurality of wafers in a region to be processed includes: a holding step for directly holding the processed object on a holding platform; and a laser processing step for implementing the holding step after the holding step is performed. The focal point of the laser beam with a penetrating wavelength of the object to be processed is positioned to the inside of the object to be held on the holding platform, and along the predetermined dividing line, only in the wafer region of the object to be processed. Irradiating the laser beam, forming a modified layer along the predetermined division line of the wafer region, and using the remaining area of the periphery as a reinforcing portion where no modified layer is formed; and a step of carrying out the laser processing After the step, the workpiece is unloaded from the holding platform; and a dividing step, after the carrying out step is performed, a force is applied to the workpiece and the workpiece is divided into individual pieces. Wafer; the dividing step, by heating and cooling to impart a force to the workpiece to be divided into individual wafer.

In one aspect of the present invention, after the laser processing step is performed, before the dividing step is performed, a reinforcing portion removing step of removing the reinforcing portion may be further provided. In one aspect of the present invention, the upper surface of the holding platform is made of a soft material, and in the holding step, the surface side of the workpiece may be held by the soft material. [Effect of the invention]

In one aspect of the method for manufacturing a wafer of the present invention, a laser beam is irradiated only on a wafer region of the processed object while the processed object is directly held on a holding platform to form a modification along a predetermined division line. Since the mass layer is then divided into individual wafers by applying a force by heating and cooling, there is no need to use an expansion sheet in order to divide the workpiece into individual wafers by applying force. As described above, according to the wafer manufacturing method according to one aspect of the present invention, a plurality of wafers can be manufactured by dividing a plate-shaped workpiece, that is, a workpiece without using an expansion sheet.

In addition, in a method for manufacturing a wafer according to one aspect of the present invention, a laser beam is irradiated only on a wafer region of a workpiece to form a modified layer along a predetermined division line, and the remaining area on the outer periphery is regarded as a non-formed modified layer. The reinforcement part of the texture layer, so the wafer area will be reinforced by this reinforcement part. Therefore, the object to be processed is not divided into individual wafers due to a force applied during transportation or the like, and the object to be processed cannot be appropriately transferred.

An embodiment of the present invention will be described with reference to the drawings. The method for manufacturing a wafer according to this embodiment includes a holding step (refer to FIG. 3 (A)), a laser processing step (refer to FIG. 3 (B), FIG. 4 (A), and FIG. 4 (B)), a carrying-out step, and reinforcement. Part removal step (see FIG. 5 (A) and FIG. 5 (B)), and division step (see FIG. 6).

In the holding step, a workpiece (workpiece) having a wafer region divided into a plurality of regions by dividing a predetermined line and a remaining area surrounding the periphery of the wafer region is directly held by a chuck table (holding table). In the laser processing step, a laser beam having a wavelength penetrating the object to be processed is irradiated, and a modified layer (modified region) along a predetermined division line is formed in the wafer region, and the remaining region on the outer periphery is regarded as not formed. There is a reinforcement section of the reforming layer.

In the unloading step, the workpiece is removed from the holding platform. In the reinforcing portion removing step, the reinforcing portion is removed from the workpiece. In the dicing step, a workpiece is divided into a plurality of wafers by applying a force by heating and cooling. Hereinafter, a method for manufacturing a wafer according to this embodiment will be described in detail.

FIG. 1 is a schematic perspective view showing a model of a configuration example of a workpiece (workpiece) 11 used in this embodiment. As shown in FIG. 1, the processed object 11 is, for example, a semiconductor made of silicon (Si), gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), silicon carbide (SiC), or sapphire. (Al ₂ O ₃ ), dielectrics (insulators) such as soda glass, borosilicate glass, quartz glass, or ferroelectrics (ferroelectrics) such as lithium tantalate (LiTa ₃ ), lithium niobate (LiNb ₃ ) (Crystal) wafers (substrates).

On the side of the surface 11a of the workpiece 11, a plurality of intersecting division lines (cutting lines) 13 are divided into a plurality of regions 15 as a wafer. In the following, a substantially circular region including all of the plurality of regions 15 as a wafer is referred to as a wafer region 11c, and a ring-shaped region surrounding the wafer region 11c is referred to as a peripheral outer region 11d.

In each region 15 in the wafer region 11c, ICs (Integrated Circuit), MEMS (Micro Electro Mechanical Systems), LEDs (Light Emitting Diode), LDs (Laser Diode), Photodiodes, and SAW ( Surface Acoustic Wave (surface acoustic wave) filter, BAW (Bulk Acoustic Wave) filter and other components.

A plurality of wafers are obtained by dividing the object to be processed 11 along a predetermined dividing line 13. Specifically, when the processed object 11 is a silicon wafer, for example, a wafer that functions as a memory or a sensor is obtained. When the workpiece 11 is a gallium arsenide substrate, an indium phosphide substrate, or a gallium nitride substrate, for example, a wafer that functions as a light emitting element or a light receiving element is obtained.

When the processed object 11 is a silicon carbide substrate, for example, a wafer that functions as a power element or the like is obtained. When the workpiece 11 is a sapphire substrate, for example, a wafer that functions as a light emitting element or the like is obtained. When the workpiece 11 is a glass substrate made of soda glass, borosilicate glass, quartz glass, or the like, for example, a wafer serving as an optical component or a protective member (protective glass) is obtained.

When the workpiece 11 is a ferroelectric substrate (ferroelectric crystal substrate) made of a ferroelectric material such as lithium tantalate or lithium niobate, for example, a wafer serving as a filter or an actuator is obtained. . In addition, the material, shape, structure, size, thickness, etc. of the workpiece 11 are not limited. Similarly, the type, number, shape, structure, size, arrangement, etc. of the elements formed in the region 15 as a wafer are not limited. In the region 15 as a wafer, no element may be formed.

In the wafer manufacturing method of this embodiment, a disc-shaped silicon wafer is used as the object 11 to manufacture a plurality of wafers. Specifically, first, a holding step of directly holding the workpiece 11 on a chuck table is performed. FIG. 2 is a schematic perspective view showing a model of a configuration example of a laser processing apparatus used in the embodiment.

As shown in FIG. 2, the laser processing apparatus 2 includes a base 4 on which each component is mounted. On the base 4, a chuck platform (holding platform) 6 for attracting and holding the workpiece 11 is provided to move in the X-axis direction (processing feed direction) and the Y-axis direction (index feeding direction). Horizontal movement mechanism 8. The horizontal moving mechanism 8 is fixed to the upper surface of the base 4 and includes a pair of X-axis guide rails 10 substantially parallel to the X-axis direction.

An X-axis moving platform 12 is slidably mounted on the X-axis guide 10. A nut portion (not shown) is provided on the back side (lower side) of the X-axis moving platform 12, and an X-axis ball screw 14 substantially parallel to the X-axis guide 10 is screwed into the nut portion.

An X-axis pulse motor 16 is connected to one end of the X-axis ball screw 14. The X-axis ball screw 14 is rotated by the X-axis pulse motor 16, whereby the X-axis moving platform 12 moves along the X-axis guide 10 in the X-axis direction. An X-axis scale 18 is provided at a position adjacent to the X-axis guide 10 for detecting the position of the X-axis moving platform 12 in the X-axis direction.

A pair of Y-axis guide rails 20 are fixed to the surface (upper surface) of the X-axis moving platform 12 in a direction substantially parallel to the Y-axis direction. A Y-axis moving platform 22 is slidably mounted on the Y-axis guide 20. A nut portion (not shown) is provided on the back side (lower side) of the Y-axis moving platform 22, and a Y-axis ball screw 24 that is substantially parallel to the Y-axis guide 20 is screwed into the nut portion.

A Y-axis pulse motor 26 is connected to one end of the Y-axis ball screw 24. The Y-axis ball screw 24 is rotated by the Y-axis pulse motor 26, whereby the Y-axis moving platform 22 moves along the Y-axis guide 20 in the Y-axis direction. A Y-axis scale 28 is provided at a position adjacent to the Y-axis guide 20 to detect the position of the Y-axis moving platform 22 in the Y-axis direction.

A support table 30 is provided on the front side (upper surface side) of the Y-axis moving platform 22, and a chuck platform 6 is arranged on the upper portion of the support table 30. The surface (upper surface) of the chuck table 6 is a holding surface 6a that attracts and holds the back surface 11b side (or surface 11a side) of the workpiece 11 described above. The holding surface 6a is made of a porous material having high hardness such as alumina. However, the holding surface 6a may be made of a soft material typified by a resin such as polyethylene or epoxy.

This holding surface 6a is connected to a suction source 34 (refer to FIG. 3) through a suction path 6b (refer to FIG. 3 (A), etc.) or a valve 32 (refer to FIG. 3 (A), etc.) formed inside the chuck platform 6. (A), etc.). A rotary drive source (not shown) is provided below the chuck platform 6, and the chuck platform 6 rotates around a rotation axis substantially parallel to the Z-axis direction by the rotary drive source.

Behind the horizontal moving mechanism 8 is provided a columnar support structure 36. A support arm 38 extending in the Y-axis direction is fixed to the upper portion of the support structure 36. A pulse end of the support arm 38 is provided with a wavelength that is transparent to the workpiece 11 (a wavelength that is difficult to be absorbed). ) And a laser beam 17 (see FIG. 3 (B)), and a laser irradiation unit 40 that irradiates the workpiece 11 on the chuck table 6.

At a position adjacent to the laser irradiation unit 40, a camera 42 for photographing the front surface 11a side or the back surface 11b side of the workpiece 11 is provided. An image formed by photographing the object 11 or the like with the camera 42 is used when, for example, the positions of the object 11 and the laser irradiation unit 40 are adjusted.

Components such as the chuck platform 6, the horizontal movement mechanism 8, the laser irradiation unit 40, and the camera 42 are connected to a control unit (not shown). The control unit controls each component so that the workpiece 11 is appropriately processed.

FIG. 3 (A) is a sectional view for explaining the division step. In addition, in Fig. 3 (A), a part of the constituent elements are shown by functional blocks. In the holding step, as shown in FIG. 3 (A), for example, the back surface 11 b of the workpiece 11 is brought into contact with the holding surface 6 a of the chuck table 6. Then, the valve 32 is opened so that the negative pressure of the suction source 34 acts on the holding surface 6a.

Thereby, the to-be-processed object 11 is attracted and hold | maintained on the holding platform 6 in the state which the surface 11a side exposed upwards. In this embodiment, as shown in FIG. 3 (A), the back surface 11b side of the workpiece 11 is directly held by the chuck table 6. That is, in this embodiment, it is not necessary to stick an expansion sheet to the to-be-processed object 11.

After the holding step, a laser processing step of irradiating a laser beam 17 having a wavelength penetrating to the workpiece 11 to form a modified layer along a predetermined division line 13 is performed. FIG. 3 (B) is a cross-sectional view for explaining the laser processing steps, FIG. 4 (A) is a schematic plan view of the state of the workpiece 11 after the laser processing steps, and FIG. 4 (B) is a laser processing A schematic sectional view of the state of the processed object 11 after the step is modeled. In addition, in Fig. 3 (B), a part of the constituent elements are shown by functional blocks.

In the laser processing step, first, the chuck table 6 is rotated, for example, the extension direction of the target division line 13 is parallel to the X-axis direction. Next, the chuck table 6 is moved to align the position of the laser irradiation unit 40 on the extension line of the target division line 13. Then, as shown in FIG. 3 (B), the chuck table 6 is moved in the X-axis direction (that is, the extending direction of the target division line 13).

Thereafter, when the laser irradiation unit 40 has reached one of the boundaries between the wafer region 11c and the remaining peripheral region 11d at two locations on the target division line 13, the laser irradiation unit is from there. 40 starts irradiation of the laser beam 17. In this embodiment, as shown in FIG. 3 (B), a laser beam 17 is irradiated from the laser irradiation unit 40 disposed above the workpiece 11 toward the surface 11 a of the workpiece 11.

This irradiation of the laser beam 17 is continued until the laser irradiation unit 40 reaches directly above the other side of the boundary between the wafer region 11c and the remaining peripheral region 11d at the two target division lines 13. That is, here, the laser beam 17 is irradiated only in the wafer region 11 c along the target division line 13.

In addition, this laser beam 17 is irradiated so that a light-condensing point is positioned in the inside of the to-be-processed object 11 from the front surface 11a (or the back surface 11b) by predetermined depth. In this manner, the laser beam 17 having a wavelength penetrating to the workpiece 11 is condensed inside the workpiece 11, and thus, a part of the workpiece 11 at the light-condensing point and its vicinity can be processed by The multiphoton absorption is modified to form a reformed layer (modified region) 19 which is the starting point of segmentation. In this embodiment, since the laser beam 17 is irradiated only along the target division line 13 in the wafer region 11c, the modified layer 19 is formed only in the wafer region 11c along the target division line 13.

After the modified layer 19 is formed at a position of a predetermined depth along the target division line 13, the modified layer 19 is formed at a position of another depth along the target division line 13 in the same procedure. Specifically, for example, as shown in FIG. 4 (B), the modified layer 19 (the first modified layer 19a) is formed at three positions having different depths from the front surface 11a (or the back surface 11b) of the workpiece 11. , Second modified layer 19b, third modified layer 19c).

However, the number or position of the modified layers 19 formed along one predetermined division line 13 is not particularly limited. For example, the number of the modified layers 19 formed along one predetermined division line 13 may be set to one. The modified layer 19 is preferably formed under conditions where cracks reach the front surface 11a (or the back surface 11b). Of course, the modified layer 19 may also be formed under conditions that the cracks reach both the front surface 11a and the back surface 11b. Thereby, the workpiece 11 can be appropriately divided.

When the processed object 11 is a silicon wafer, the modified layer 19 is formed under the following conditions, for example. Processed object: Silicon wafer laser beam wavelength: 1340nm Repeating frequency of laser beam: 90kHz Laser beam output: 0.1W ～ 2W Movement speed of chuck platform (processing feed speed): 180mm / s ～ 1000mm / s, the representative is 500mm / s

When the workpiece 11 is a gallium arsenide substrate or an indium phosphide substrate, for example, the modified layer 19 is formed under the following conditions. Processed object: gallium arsenide substrate, indium phosphide substrate laser beam wavelength: 1064nm Repeating frequency of laser beam: 20kHz Laser beam output: 0.1W ～ 2W Movement speed of chuck platform (processing feed Speed): 100mm / s ～ 400mm / s, the representative is 200mm / s

When the workpiece 11 is a sapphire substrate, the modified layer 19 is formed under the following conditions, for example. Processed object: Wavelength of sapphire substrate laser beam: 1045nm 的 Repeating frequency of laser beam: 100kHz Output of laser beam: 0.1W ～ 2W 移动 Movement speed of chuck platform (processing feed speed): 400mm / s ～ 800mm / s, the representative is 500mm / s

When the workpiece 11 is a ferroelectric substrate made of a ferroelectric such as lithium tantalate or lithium niobate, the modified layer 19 is formed under the following conditions, for example. Processed object: lithium tantalate substrate, lithium niobate substrate laser beam wavelength: 532nm Repeating frequency of laser beam: 15kHz Laser beam output: 0.02W ～ 0.2W Movement speed of chuck platform (processing Feeding speed): 270mm / s ～ 420mm / s, representative is 300mm / s

When the workpiece 11 is a glass substrate made of soda glass, borosilicate glass, quartz glass, or the like, the modified layer 19 is formed under the following conditions, for example. Object to be processed: Sodium glass substrate, borosilicate glass substrate, quartz glass substrate Laser beam wavelength: 532nm Repeating frequency of laser beam: 50kHz Laser beam output: 0.1W ～ 2W Movement of chuck platform Speed (processing feed speed): 300mm / s ～ 600mm / s, representative is 400mm / s

When the workpiece 11 is a gallium nitride substrate, the modified layer 19 is formed under the following conditions, for example. Processed object: GaN substrate laser beam wavelength: 532nm Repeating frequency of laser beam: 25kHz Laser beam output: 0.02W ～ 0.2W Movement speed of chuck platform (processing feed speed): 90mm / S ～ 600mm / s, the representative is 150mm / s

When the workpiece 11 is a silicon carbide substrate, the modified layer 19 is formed under the following conditions, for example. Processed object: Silicon carbide substrate laser beam wavelength: 532nm Repeating frequency of laser beam: 25kHz Laser beam output: 0.02W ～ 0.2W, representative is 0.1W Movement speed of chuck platform (processing Feed speed): 90mm / s ～ 600mm / s, represented by the cleavage direction of the silicon carbide substrate is 90mm / s, and the non-cleave direction is 400mm / s

After the necessary number of reforming layers 19 are formed along the target dividing line 13, the above-mentioned operation is repeated, and the reforming layers 19 are shaped along all the other dividing lines 13. As shown in FIG. 4 (A), once the modified layer 19 is formed along all the planned division lines 13, the laser processing step ends.

In this embodiment, the modified layer 19 is formed only in the wafer region 11c along the planned division line 13. The modified layer 19 is not formed in the remaining peripheral region 11d. Therefore, the processed part is retained by the remaining peripheral region 11d. The strength of the object 11. This prevents the workpiece 11 from being divided into individual wafers due to a force applied during transportation or the like. In this manner, the remaining peripheral area 11d after the laser processing step functions as a reinforcing portion for reinforcing the wafer area 11 on which the modified layer 19 is formed.

In addition, in the present embodiment, since the modified layer 19 is not formed in the remaining peripheral area 11d, for example, even when a crack extending from the modified layer 19 reaches both the front surface 11a and the back surface 11b, the workpiece 11 is completely divided. , Each wafer will still not fall off and scatter. Generally, if a modified layer 19 is formed on the workpiece 11, the workpiece 11 will swell in the vicinity of the modified layer 19 here. In this embodiment, the swelling force caused by the formation of the reforming layer 19 acts inwardly on the annular remaining area 11d serving as a reinforcing portion, thereby pushing against the wafers to prevent falling and scattering. .

After the laser processing step, a step of removing the workpiece 11 from the chuck table 6 is performed. Specifically, for example, a transport unit (not shown) capable of adsorbing and holding the entire surface 11a (or the back surface 11b) of the workpiece 11 adsorbs the entire surface 11a of the workpiece 11, and then closes the valve 32 to The negative pressure of the suction source 34 is shielded, and the workpiece 11 is carried out. In addition, in this embodiment, as described above, the remaining peripheral area 11d acts as a reinforcing portion, so that the workpiece 11 is not divided into individual wafers due to a force applied during transportation or the like, and the workpiece cannot be appropriately transferred. Processed product 11.

After the unloading step, a reinforcing portion removing step of removing the reinforcing portion from the workpiece 11 is performed. 5 (A) and 5 (B) are cross-sectional views for explaining a step of removing a reinforcing portion. In addition, in FIG. 5 (A) and FIG. 5 (B), a part of components are shown by a functional block. The step of removing the reinforcing portion is performed using, for example, the dividing device 52 shown in FIGS. 5 (A) and 5 (B).

The dividing device 52 includes a chuck platform 54 for attracting and holding the workpiece 11. A part of the upper surface of the chuck table 54 is a holding surface 54 a that attracts and holds the wafer region 11 c of the workpiece 11. The holding surface 54 a is connected to a suction source 58 through a suction path 54 b, a valve 56, or the like formed inside the chuck platform 54. A heater (heating unit) 54c is arranged below the holding surface 54a.

The other part of the upper surface of the chuck platform 54 is open at one end of a suction path 54d for sucking and holding the remaining area 11d (that is, the reinforcing portion) of the workpiece 11. The other end side of the suction path 54d is connected to a suction source 58 through a valve 60 or the like. The chuck platform 54 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to a vertical direction.

A cutting unit 62 is arranged above the chuck table 54. The cutting unit 62 includes a mandrel 64 as a rotation axis that is substantially parallel to the holding surface 54a. On one end side of the mandrel 64, a ring-shaped cutting blade 66 in which particles are dispersed in a bonding material is mounted.

A rotary drive source (not shown) such as a motor is connected to the other end side of the mandrel 64, and a cutter 66 attached to one end side of the mandrel 64 is rotated by a force transmitted from the rotary drive source. The cutting unit 62 is supported by, for example, an elevating mechanism (not shown), and the cutter 66 is moved in the vertical direction by the elevating mechanism.

On the upper surface of the chuck table 54, at the position corresponding to the boundary between the wafer region 11 c of the workpiece 11 and the remaining peripheral region 11 d, a cutting-out avoidance groove (not shown) for preventing contact with the cutting cutter 66 is formed. Icon).

In the reinforcing portion removing step, first, the back surface 11 b of the workpiece 11 is brought into contact with the holding surface 54 a of the chuck table 54. Then, the valves 56 and 60 are opened so that the negative pressure of the suction source 58 acts on the holding surface 54a and the like. Thereby, the to-be-processed object 11 is attracted and hold | maintained to the chuck table 54 in the state which the surface 11a side exposed upwards. In this embodiment, as shown in FIG. 5 (A), the back surface 11b side of the workpiece 11 is directly held by the chuck table 54. That is, there is no need to attach an expansion sheet to the workpiece 11 here.

Next, the cutter 66 is rotated and cut to the boundary between the wafer region 11c of the workpiece 11 and the remaining peripheral region 11d. At the same time, as shown in FIG. 5 (A), the chuck platform 54 is rotated about a rotation axis substantially parallel to the vertical direction. Thereby, the to-be-processed object 11 can be cut | disconnected along the boundary of the wafer area 11c and the remaining peripheral area 11d.

Thereafter, the valve 60 is closed to shield the negative pressure of the suction source 58 with respect to the remaining area 11 d of the outer periphery of the workpiece 11. Then, as shown in FIG. 5 (B), the remaining peripheral area 11 d is removed from the chuck table 54. As a result, only the wafer region 11 c of the workpiece 11 remains on the chuck table 54.

After the reinforcing portion removing step, a dividing step of dividing the workpiece 11 into individual wafers is performed. Specifically, the workpiece 11 is divided by stressing it by heating and cooling. FIG. 6 is a cross-sectional view for explaining the division step. In addition, in FIG. 6, a part of the constituent elements is shown as a functional block.

The dividing step is continued using the dividing device 52. As shown in FIG. 6, the dividing device 52 further includes a nozzle (cooling unit) 68 disposed above the chuck table 54. In the dividing step of the present embodiment, the workpiece 11 is heated by a heater 54c provided on the chuck table 54 and the cooling fluid 21 is supplied from the nozzle 68 to cool the workpiece 11 to thereby divide the workpiece 11 The stress required for the work 11 is generated.

As the cooling fluid 21, for example, a liquid such as water or a gas such as air can be used. When a liquid is used as the fluid 21, the liquid may be cooled in advance to a low temperature that does not freeze (for example, a temperature about 0.1 ° C to 10 ° C higher than the freezing point). However, the type, flow rate, temperature, and the like of the fluid 21 are not particularly limited. For example, a low-temperature liquid such as hot liquid nitrogen that can further take away hot gas by vaporization may be used.

After the heater 54 c is operated to heat the workpiece 11, once the cooling fluid 21 is supplied from the nozzle 68 to cool the workpiece 11, the workpiece 11 is modified by the stress generated in the workpiece 11. The layer 19 extends out of a crack 23. Thereby, the workpiece 11 is divided into a plurality of wafers 25 along the planned division line 13.

Conditions for heating and cooling (temperature, time, etc.) are set in accordance with the type of the workpiece 11 and the like. The heating of the workpiece 11 by the heater 54 c and the cooling of the workpiece 11 by the liquid 21 supplied from the nozzle 68 are preferably repeated until the workpiece 11 is appropriately divided.

As described above, in the present embodiment, a necessary force is applied by heating and cooling, whereby the workpiece 11 can be divided into individual wafers 25. In the present embodiment, the workpiece 11 is heated and then cooled, but the workpiece 11 may be cooled and then heated. There are also no particular restrictions on the method of heating and cooling.

As described above, in the method for manufacturing a wafer of this embodiment, the workpiece (workpiece) 11 is directly held on the chuck table (holding table) 6 and only the wafer region 11c of the workpiece 11 is irradiated. The laser beam 17 forms a modified layer 19 along a predetermined division line 13, and thereafter, the object to be processed 11 is divided into individual wafers 25 by applying a force by heating and cooling, so there is no need to apply the object 11 The wafer is divided into individual wafers 25 by force, and an expansion sheet is used. As described above, according to the wafer manufacturing method of this embodiment, it is possible to manufacture a plurality of wafers 25 by dividing a plate-like workpiece 11, that is, a silicon wafer, without using an expansion sheet.

In addition, in the method for manufacturing a wafer of this embodiment, a laser beam 17 is irradiated only on the wafer region 11c of the workpiece 11 to form a modified layer 19 along the planned division line 13. The remaining region 11d on the outer periphery is defined as Since the reinforcing portion of the modified layer 19 is not formed, the wafer region 11c is reinforced by the reinforcing portion. Therefore, the workpiece 11 is not divided into individual wafers 25 due to a force applied during transportation or the like, and the workpiece 11 cannot be appropriately transferred.

In addition, the present invention is not limited to the description of the above-mentioned embodiments and the like, and can be implemented with various modifications. For example, in the holding step of the above embodiment, the back surface 11b side of the workpiece 11 is directly held by the chuck table 6 and the laser beam 17 is irradiated from the surface 11a side. However, the surface of the workpiece 11 may be held The 11a side is held directly by the chuck platform 6, and the laser beam 17 is irradiated from the back side 11b side.

FIG. 7 is a cross-sectional view for explaining a holding procedure of a modification. In the holding step of this modification, as shown in FIG. 7, for example, a porous sheet (porous sheet) 44 made of a soft material typified by a resin such as polyethylene or epoxy can be used to constitute the upper sheet. Chuck platform (holding platform) 6.

In this chuck table 6, the upper surface 44a of the sheet 44 is used to attract and hold the surface 11a side of the workpiece 11. Thereby, breakage of an element or the like formed on the surface 11a side can be prevented. This piece 44 is a part of the chuck platform 6, and is repeatedly used together with the body of the chuck platform 6.

However, the upper surface of the chuck table 6 does not need to be constituted by the porous sheet 44 described above, as long as it is composed of a soft material at least to the extent that it does not damage the elements or the like formed on the surface 11a side of the workpiece 11. Just fine. The sheet 44 is preferably configured to be attachable to and detachable from the main body of the chuck platform 6, and to be exchanged in the case of damage.

Further, in the above-mentioned embodiment, the reinforcing portion removing step is performed after the carrying-out step and before the dividing step, but for example, the reinforcing portion removing step may be performed after the laser processing step and before the carrying-out step. In addition, when the reinforcing portion removing step is performed after the carrying-out step and before the dividing step, there is no need to transfer the processed object 11 after the reinforcing portion removing step, so problems such as failure to properly transfer the processed object 11 are easily avoided.

In addition, the step of removing the reinforcing portion can be omitted. In this case, for example, the range of forming the modified layer 19 can be adjusted by a laser processing step so that the width of the reinforcing portion is approximately 2 mm to 3 mm from the outer periphery of the workpiece 11. In addition, for example, before the wafer region 11c is divided in the division step, a groove as a starting point of division may be formed in the reinforcing portion. FIG. 8 (A) is a cross-sectional view for explaining the dividing step of the modified example, and FIG. 8 (B) is a schematic model plan view of the state of the workpiece 11 before the wafer region 11c is divided by the dividing step of the modified example.

In the dividing step of the modified example, as shown in FIGS. 8 (A) and 8 (B), the cutter 66 is cut into the remaining area 11d (that is, the reinforcing portion) to form a groove 11e as a starting point of the division. This groove 11e is preferably formed along, for example, a predetermined division line 13. By forming such a groove 11e, the workpiece 11 and the remaining peripheral area 11d can be divided by a force generated by heating and cooling. In the dividing step of the modification, the suction path 54d of the chuck table 54, the valve 60, and the like can be omitted.

The structures and methods of the other embodiments and modifications can be appropriately modified and implemented without departing from the scope of the present invention.

11‧‧‧ Object (workpiece)

11a‧‧‧ surface

11b‧‧‧Back

11c‧‧‧Chip area

11d‧‧‧External area

13‧‧‧ divided scheduled line (cutting line)

15‧‧‧area

17‧‧‧ laser beam

19‧‧‧ Reformed layer (reformed area)

19a‧‧‧The first reforming layer

19b‧‧‧The second reforming layer

19c‧‧‧The third reformed layer

21‧‧‧fluid

23‧‧‧ Rift

25‧‧‧Chip

2‧‧‧laser processing equipment

4‧‧‧ abutment

6‧‧‧ chuck platform (holding platform)

6a‧‧‧ holding surface

6b‧‧‧attraction path

8‧‧‧ horizontal movement mechanism

10‧‧‧X-axis guide

12‧‧‧X-axis moving platform

14‧‧‧X-axis ball screw

16‧‧‧X-axis pulse motor

18‧‧‧X-axis scale

20‧‧‧Y-axis guide

22‧‧‧Y-axis moving platform

24‧‧‧Y-axis ball screw

26‧‧‧Y-axis pulse motor

28‧‧‧Y-axis scale

30‧‧‧Support

32‧‧‧ Valve

34‧‧‧ Attraction source

36‧‧‧ support structure

38‧‧‧ support arm

40‧‧‧laser irradiation unit

42‧‧‧ Camera

44‧‧‧ tablets (porous tablets)

44a‧‧‧above

52‧‧‧ Split device

54‧‧‧Chuck platform (holding platform)

54a‧‧‧ keep face

54b‧‧‧attraction path

54c‧‧‧heater

54d‧‧‧attraction path

56‧‧‧ Valve

58‧‧‧ Attraction source

60‧‧‧ valve

62‧‧‧cutting unit

64‧‧‧ mandrel

66‧‧‧Cutter

68‧‧‧Nozzle (cooling unit)

[Fig. 1] A schematic perspective view showing a model of a structured object. [Fig. 2] A schematic perspective view of a model example of a laser processing apparatus.图 [Fig. 3] Fig. 3 (A) is a sectional view for explaining the holding step, and Fig. 3 (B) is a sectional view for explaining the laser processing step. [Fig. 4] Fig. 4 (A) is a schematic plan view of the state of the workpiece after the laser processing step, and Fig. 4 (B) is a schematic cross-sectional view of the state of the workpiece after the laser processing step. [Fig. 5] Fig. 5 (A) and Fig. 5 (B) are cross-sectional views for explaining a step of removing the reinforcing portion.图 [Fig. 6] A cross-sectional view for explaining the division step.图 [Fig. 7] A cross-sectional view for explaining a holding procedure of a modified example. [Fig. 8] Fig. 8 (A) is a cross-sectional view for explaining the dividing step of the modified example, and Fig. 8 (B) is a model representation of the state of the workpiece before the wafer region is divided by the dividing step of the modified example. Floor plan.

Claims (3)

A wafer manufacturing method includes manufacturing a plurality of wafers from a wafer region having a plurality of regions separated as a wafer by a plurality of intersecting predetermined division lines, and a workpiece surrounding a remaining area on the periphery of the wafer region. The wafer manufacturing method of the wafer includes: (i) a holding step for directly holding the processed object by a holding platform; and a laser processing step for carrying out the holding step so as to change a wavelength that is transparent to the processed object The laser beam is focused to the inside of the workpiece held on the holding platform in such a manner that the laser beam is irradiated only along the wafer area of the workpiece along the predetermined dividing line, and along A modified layer is formed along the predetermined dividing line of the wafer area, and the remaining area of the outer periphery is used as a reinforcing portion where the modified layer is not formed; and a carrying-out step, after performing the laser processing step, removing the processed object from the Holding the platform for carrying out; and a dividing step, after performing the carrying out step, applying force to the workpiece to divide the workpiece into individual crystals ; The dividing step, the heating and cooling by the force imparted to the workpiece is divided into individual wafer. The method for manufacturing a wafer according to item 1 of the scope of patent application, further comprising a step of removing the reinforcing portion after the laser processing step is performed and before the dividing step is performed. The method for manufacturing a wafer according to item 1 or 2 of the scope of patent application, wherein the upper surface of the holding platform is made of a soft material, and in the holding step, the soft material is used to hold the processed material. Surface side of the object.