TWI832975B - Processing device and processing method - Google Patents

Abstract

An object of the invention is to reduce the time taken for processing during formation of a reformed layer inside a processing target body by irradiation of a laser light. A processing device of the invention comprises a reforming section which forms a reformed layer inside the processing target body held by a holding section, a measurement section which measures the output of the laser light, a moving section which moves the holding section between a first position at which the processing target body is transported to and from the holding section and a second position at which the reformed layer is formed by the reforming section, and a control section which controls the holding section, the reforming section, the measurement section, and the moving section. The control section controls the holding section, the measurement section, and the moving section such that the output of the laser light is measured by the measurement section when the holding section is waiting at the first position.

Description

Treatment device and treatment method

The content disclosed in the present invention relates to a processing device and a processing method.

Patent Document 1 discloses a method of manufacturing wafers from hexagonal single crystal ingots. In this manufacturing method, the focusing point of a laser beam having a wavelength that is transparent to a hexagonal single crystal ingot is positioned at a depth corresponding to the thickness of the wafer to be produced from the surface of the ingot. The focusing point is moved relative to the hexagonal single crystal ingot, and the surface of the ingot is irradiated with a laser beam to form a modified layer parallel to the surface and cracks developed from the modified layer to form a starting point for separation. Thereafter, the wafer is peeled off from the hexagonal single crystal ingot. [Known technical documents] [Patent Document]

Patent Document 1: Japanese Patent Application Laid-Open No. 2016-146448

[Problems to be solved by this invention]

The technology disclosed in the present invention shortens the processing time when the interior of the object to be processed is irradiated with laser light to form a modified layer. [Technical means to solve problems]

An aspect disclosed by the present invention is a device for processing an object to be processed, which is provided with: a holding part to hold the object to be processed; and a modifying part to irradiate the inside of the object to be processed held in the holding part with laser light to form a a modified layer; a measuring part that measures the output of the laser light; and a moving part that makes the holding part in the first position where the object to be processed is moved in and out of the holding part, and the modification is formed by the modifying part move between the second positions of the layer; and the control part controls the holding part, the modifying part, the measuring part and the moving part; the control part controls the holding part, the measuring part and the moving part so that When the holding part is waiting at the first position, the output of the laser light is measured by the measuring part. [Effects of the present invention]

According to the disclosure of the present invention, when the interior of the object to be processed is irradiated with laser light to form a modified layer, the processing time can be shortened.

In the process of manufacturing semiconductor devices, the wafer is thinned with a plurality of electronic circuits and other components formed on its surface. There are various methods for thinning the wafer, such as: grinding the back side of the wafer; or irradiating the inside of the wafer with laser light to form a modified layer, and using the modified layer as a base point to separate the wafer, etc. .

The wafer manufacturing method disclosed in the above-mentioned Patent Document 1 uses the same technology as the above-mentioned wafer thinning at the point of peeling the wafer from the hexagonal single crystal ingot. Here, when irradiating the inside of the wafer with laser light, it is necessary to confirm whether the output (power) of the laser light is appropriate (power confirmation). In addition, this power verification should be performed for each wafer to be processed. However, Patent Document 1 does not disclose the implementation of power confirmation, let alone shortening the processing time of power confirmation. Therefore, there is still room for improvement in the conventional methods.

The technology disclosed in the present invention can shorten the processing time and implement it efficiently when using laser light to form the modified layer. Hereinafter, a wafer processing system including a reforming device as a processing device and a wafer processing method as a processing method according to this embodiment, which perform wafer processing efficiently, will be described with reference to the drawings. In addition, in this specification and the drawings, elements having substantially the same functional configuration are given the same reference numerals, so that repeated explanations are omitted.

First, the structure of the wafer processing system of this embodiment will be described. FIG. 1 is a plan view schematically illustrating the structure of the wafer processing system 1 .

The wafer processing system 1, as shown in FIGS. 2 and 3, performs predetermined processing on the overlapping wafer T as the overlapping substrate. The overlapping wafer T combines the to-be-processed wafer W as the first substrate and the wafer W as the second substrate. Supports wafer S-bonding. Then, the wafer processing system 1 removes the peripheral portion We of the wafer W to be processed, and further thins the wafer W to be processed. Hereinafter, in the wafer W to be processed, the surface bonded to the supporting wafer S is called the front surface Wa, and the surface opposite to the front surface Wa is called the back surface Wb. Similarly, in the support wafer S, the surface bonded to the wafer W to be processed is called the front surface Sa, and the surface opposite to the surface Sa is called the back surface Sb.

The wafer W to be processed is, for example, a semiconductor wafer such as a silicon wafer, and an element layer (not shown) including a plurality of elements is formed on the surface Wa. In addition, an oxide film F, such as a SiO ₂ film (TEOS film), is further formed on the element layer. In addition, the peripheral portion We of the wafer W to be processed is chamfered; the thickness of the cross section of the peripheral portion We becomes smaller toward the front end. In addition, the peripheral portion We is a portion removed in so-called peripheral edge trimming, and is, for example, a range of 1 mm to 5 mm in the radial direction from the outer end of the wafer W to be processed.

In addition, in FIG. 2 , in order to avoid the complexity of the illustration, the illustration of the oxide film F is omitted. In addition, in other figures used in the following description, the illustration of the oxide film F may also be omitted in some cases.

The supporting wafer S is a wafer that supports the wafer W to be processed, such as a silicon wafer. An oxide film (not shown) is formed on the surface Sa of the supporting wafer S. In addition, the supporting wafer S functions as a protective material for protecting elements on the surface Wa of the wafer W to be processed. In addition, when forming a plurality of elements supporting the surface Sa of the wafer S, an element layer (not shown) is formed on the surface Sa in the same manner as the wafer W to be processed.

Here, in the peripheral portion We of the wafer to be processed W, if the wafer to be processed W and the supporting wafer S are bonded, the peripheral portion We may not be appropriately removed. Therefore, at the interface between the wafer to be processed W and the support wafer S, a bonding area Aa is formed in which the oxide film F is bonded to the surface Sa of the supporting wafer S, and an unbonded area Ab, which is a region radially outside the bonding area Aa, is formed. By allowing the unjoined area Ab to exist in this way, the peripheral portion We can be appropriately removed. In addition, the outer end portion of the joint area Aa is located slightly outward in the radial direction than the inner end portion of the peripheral portion We except which the peripheral edge portion We is removed.

As shown in FIG. 1 , the wafer processing system 1 has a structure in which a loading/unloading station 2 and a processing station 3 are integrally connected. The loading and unloading station 2 carries out, for example, a wafer cassette Ct that can accommodate a plurality of overlapping wafers T between the station and the outside. The processing station 3 is equipped with various processing devices for performing predetermined processing on the overlapped wafer T.

In the transfer station 2, a wafer cassette placing table 10 is provided. In the example shown in the figure, a plurality of, for example, three wafer cassettes Ct are arbitrarily placed in a row in the Y-axis direction on the wafer cassette mounting table 10 . In addition, the number of wafer cassettes Ct placed on the wafer cassette mounting table 10 is not limited to this embodiment and can be determined arbitrarily.

In the loading/unloading station 2 , a wafer transfer device 20 is provided adjacent to the wafer cassette mounting table 10 on the negative side of the X-axis direction of the wafer cassette mounting table 10 . The wafer transfer device 20 is configured to move arbitrarily on the transfer path 21 extending in the Y-axis direction. In addition, the wafer transport device 20 is provided with, for example, two transport arms 22 and 22 for holding and transporting the stacked wafer T. Each transfer arm 22 is configured to be movable in the horizontal direction, in the vertical direction, around the horizontal axis, and around the vertical axis. In addition, the structure of the conveyance arm 22 is not limited to this embodiment, and any structure can be adopted. The wafer transport device 20 is configured to transport the stacked wafer T to the wafer cassette Ct of the wafer cassette mounting table 10 and the transfer device 30 described below.

In the loading/unloading station 2 , a transfer device 30 for transferring the overlapped wafer T is provided adjacent to the wafer transfer device 20 on the negative side in the X-axis direction.

In the processing station 3, for example, three processing blocks G1 to G3 are provided. The first processing block G1, the second processing block G2, and the third processing block G3 are arranged side by side in the above-mentioned order from the positive direction side of the X-axis (the transfer station 2 side) toward the negative direction side.

In the first processing block G1, an etching device 40, a cleaning device 41, and a wafer transport device 50 are provided. The etching device 40 and the cleaning device 41 are stacked and arranged. In addition, the number and arrangement of the etching devices 40 and the cleaning devices 41 are not limited to this form. For example, the etching device 40 and the cleaning device 41 may each extend in the X-axis direction and be placed side by side in a plan view. Furthermore, the etching device 40 and the cleaning device 41 may be stacked separately.

The etching device 40 etches the back surface Wb of the wafer W polished by the processing device 80 described below. For example, a chemical solution (etching liquid) is supplied to the back surface Wb, and the back surface Wb is wet-etched. As a chemical solution, for example, HF, HNO ₃ , H ₃ PO ₄ , TMAH, Choline, KOH, etc. are used.

The cleaning device 41 cleans the back surface Wb of the wafer W to be processed that has been polished by the processing device 80 described below. For example, the brush is brought into contact with the back surface Wb and the back surface Wb is scrubbed and cleaned. In addition, pressurized cleaning fluid can also be used to clean the back Wb. In addition, the cleaning device 41 may be configured to clean the back surface Sb of the supporting wafer S and the back surface Wb of the wafer W to be processed together.

The wafer transfer device 50 is, for example, disposed on the negative Y-axis direction side with respect to the etching device 40 and the cleaning device 41 . The wafer transport device 50 includes, for example, two transport arms 51 and 51 for holding and transporting the stacked wafer T. Each transfer arm 51 is configured to be movable in the horizontal direction, in the vertical direction, around the horizontal axis, and around the vertical axis. In addition, the structure of the transfer arm 51 is not limited to this embodiment, and any structure can be adopted. The wafer transport device 50 is configured to transport the stacked wafer T to the transfer device 30 , the etching device 40 , the cleaning device 41 , and the modification device 60 described below.

In the second processing block G2, a modification device 60, a peripheral edge removal device 61, and a wafer transfer device 70 are provided. The reforming device 60 and the peripheral edge removing device 61 are stacked and arranged. In addition, the number and arrangement of the reforming devices 60 and the peripheral edge removing devices 61 are not limited to this form.

The modifying device 60 irradiates the inside of the wafer W to be processed with laser light to form a peripheral modified layer, a divided modified layer, and an internal surface modified layer. The specific structure of the reforming device 60 will be described later.

The peripheral edge removal device 61 removes the peripheral edge portion We of the wafer W to be processed based on the peripheral edge modification layer formed by the modification device 60 . The specific structure of the peripheral edge removal device 61 will be described later.

The wafer transfer device 70 is arranged, for example, on the Y-axis positive direction side with respect to the modifying device 60 and the peripheral edge removal device 61 . The wafer transport device 70 includes, for example, two transport arms 71 and 71 for holding and transporting the stacked wafer T. Each transfer arm 71 is supported by a multi-joint arm member 72 and is configured to be movable in the horizontal direction, in the vertical direction, around the horizontal axis, and around the vertical axis. The specific structure of the transfer arm 71 will be described later. The wafer transport device 70 is configured to transport the stacked wafer T to the cleaning device 41 , the reforming device 60 , the peripheral edge removal device 61 , and the processing device 80 described below.

In the third processing block G3, a processing device 80 is installed. In addition, the number and arrangement of the processing devices 80 are not limited to this embodiment, and a plurality of processing devices 80 may be arranged arbitrarily.

The processing device 80 grinds the back surface Wb of the wafer W to be processed. Then, on the back surface Wb where the inner surface modified layer is formed, the inner surface modified layer is removed, and the peripheral modified layer is further removed.

The processing device 80 includes a rotary table 81 . The rotary table 81 is configured to be arbitrarily rotatable around a vertical rotation center line 82 by a rotary mechanism (not shown). On the rotating stage 81, two suction cups 83 for sucking and holding the overlapping wafer T are provided. The suction cups 83 are equally arranged on the same circumference as the rotary table 81 . By rotating the turntable 81, the two suction cups 83 become movable between the transfer position A0 and the processing position A1. In addition, each of the two suction cups 83 is configured to be rotatable around a vertical axis by a rotation mechanism (not shown).

At the transfer position A0, the overlapped wafer T is transferred. In the processing position A1, the grinding unit 84 is arranged. In the polishing unit 84, the back surface Wb of the wafer W to be processed is polished. The grinding unit 84 has a grinding part 85, and the grinding part 85 has a ring-shaped grinding wheel (not shown) that can rotate arbitrarily. In addition, the polishing part 85 is configured to be movable in the vertical direction along the support column 86 . Then, with the grinding wheel in contact with the back surface Wb of the wafer W held by the suction cup 83, the suction cup 83 and the grinding wheel are rotated respectively to grind the back surface Wb.

The above-mentioned wafer processing system 1 is provided with a control device 90 as a control unit. The control device 90 is, for example, a computer and includes a program storage unit (not shown). The program storage section stores programs for controlling the processing of the overlapping wafer T in the wafer processing system 1 . In addition, the program storage portion also stores programs used to control the operation of the above-mentioned various processing devices, transport devices and other driving systems to realize the wafer processing described below in the wafer processing system 1 . In addition, the above-mentioned program may be recorded on a computer-readable recording medium H and installed in the control device 90 from the recording medium H.

Next, the above-mentioned reforming device 60 will be described. FIG. 4 is a plan view showing an outline of the structure of the reforming device 60 . FIG. 5 is a side view showing an outline of the structure of the reforming device 60 .

The modifying device 60 is provided with a suction cup 100 as a holding part, and the suction cup 100 holds the stacked wafer T on the top surface. The suction cup 100 adsorbs and holds the supporting wafer S with the wafer W to be processed being on the upper side and the supporting wafer S being on the lower side. The suction cup 100 is supported on the sliding table 102 via the air bearing 101 . A rotation mechanism 103 as a rotation unit is provided on the bottom surface side of the slide table 102 . The rotation mechanism 103 serves as a driving source, such as a built-in motor. The suction cup 100 is configured to be arbitrarily rotatable around a vertical axis by the rotation mechanism 103 via the air bearing 101 . The sliding table 102 is configured to be movable along the rail 105 provided on the base 106 and extending in the Y-axis direction by the moving mechanism 104 as the moving part provided on the bottom side thereof. In addition, the driving source of the moving mechanism 104 is not particularly limited, and for example, a linear motor may be used.

The sliding table 102 is provided with a power meter 107 as a measuring unit, which measures the output (power) of laser light irradiated from the laser head 110 described below. The power meter 107 is provided at the end of the sliding table 102 in the negative direction of the Y-axis. As will be described later, in the first position P1, the power meter 107 is arranged below the lens of the laser head 110. The power of the laser light measured by the power meter 107 is output to the control device 90 . In the control device 90, the power of the laser light according to the treatment recipe is set, and it is confirmed whether the measured power of the laser light is appropriate (power confirmation). This power verification is performed, for example, for each wafer W to be processed, that is, the wafer W to be processed.

Above the suction cup 100, a laser head 110 as a modifying part is provided. The laser head 110 includes a lens 111 and a piezoelectric actuator 112 . The lens 111 is provided on the bottom surface of the laser head 110 and irradiates the wafer W held on the suction cup 100 with laser light. The piezoelectric actuator 112 moves the lens 111 up and down.

In addition, the laser head 110 is provided with a sensor 113 for measuring the position of the laser light irradiated from the lens 111 . The sensor 113 is provided coaxially with the laser light irradiated from the lens 111, and is, for example, an AF sensor, and measures the height of the back surface Wb of the wafer W to be processed. The height of the back surface Wb measured by the sensor 113 is output to the control device 90 . The control device 90 calculates the irradiation position of the laser light irradiated into the inside of the wafer W to be processed based on the height of the back surface Wb.

Furthermore, the laser head 110 is further provided with a sensor 114 and a camera 115, which are used to adjust the irradiation position (focus) of the laser light irradiated from the lens 111. The sensor 114 is provided non-axially with the laser light irradiated from the lens 111, and is, for example, an AF sensor. It measures the height of the back surface Wb of the wafer W to be processed and detects the back surface Wb. In addition, the sensor 114 uses an AF sensor that can measure a wider range than the sensor 113 mentioned above. In addition, the camera 115 is installed coaxially with the laser light irradiated from the lens 111, and takes an image of the back surface Wb of the wafer W to be processed. The height of the back surface Wb measured by the sensor 114 and the image of the back surface Wb captured by the camera 115 are output to the control device 90 respectively. As will be described later, the control device 90 calculates the irradiation position of the laser light irradiated into the inside of the wafer W to be processed based on the height and image of the back surface Wb.

In addition, the laser head 110 is further equipped with a spatial light modulator (not shown). The spatial light modulator modulates the laser light and outputs it. Specifically, the spatial light modulator can control the focus position and phase of the laser light, and can adjust the shape and quantity (number of branches) of the laser light irradiated to the wafer W to be processed.

Then, the laser head 110 oscillates from the laser oscillator (not shown) the high-frequency pulse-wave laser light with a wavelength that is transparent to the wafer W to be processed, and oscillates the wafer W to be processed. Spotlight is illuminated at a given location within the interior. Thereby, the portion where the laser light is focused is modified inside the wafer W to be processed, forming a peripheral modified layer, a divided modified layer, and an internal surface modified layer.

The laser head 110 is supported on the support member 116 . The laser head 110 is configured along a rail 117 extending in the vertical direction, and can be raised and lowered arbitrarily by a lifting mechanism 118 . In addition, the laser head 110 is configured to be arbitrarily movable in the Y-axis direction by the moving mechanism 119 . In addition, the lifting mechanism 118 and the moving mechanism 119 are respectively supported by the support column 120.

Above the suction cup 100, on the Y-axis positive direction side of the laser head 110, a macro camera 121 as a first imaging unit and a super macro camera 122 as a second imaging unit are provided. For example, the macro camera 121 and the super macro camera 122 are integrally configured, and the macro camera 121 is disposed on the Y-axis positive direction side of the super macro camera 122 . The macro camera 121 and the super macro camera 122 are configured to be arbitrarily raised and lowered by the lifting mechanism 123, and further configured to be arbitrarily moved in the Y-axis direction by the moving mechanism 124.

The macro camera 121 photographs the outer end of the wafer W (overlapping wafer T) to be processed. The macro camera 121 has, for example, a coaxial lens, emits visible light, such as red light, and further receives reflected light from the object. In addition, for example, the shooting magnification of the macro camera 121 is 2 times.

The ultra-macro camera 122 photographs the peripheral portion of the wafer W to be processed and the boundary between the bonded area Aa and the unbonded area Ab. The super macro camera 122 includes, for example, a coaxial lens, emits infrared light (IR light), and further receives reflected light from the object. In addition, for example, the shooting magnification of the super macro camera 122 is 10 times, the field of view is approximately 1/5 of that of the macro camera 121 , and the pixel size is approximately 1/5 of that of the macro camera 121 .

Next, the above-mentioned peripheral edge removal device 61 will be described. FIG. 6 is a plan view schematically showing the structure of the peripheral edge removing device 61 . FIG. 7 is a side view schematically showing the structure of the peripheral edge removing device 61 . FIG. 8 is an explanatory diagram schematically showing the structure of the peripheral edge removing device 61 .

The peripheral edge removal device 61 is equipped with a suction cup 130 that holds the stacked wafer T on the top surface. The suction cup 130 holds the supporting wafer S in a state where the wafer to be processed W is on the upper side and the supporting wafer S is on the lower side. In addition, the suction cup 130 is configured to be rotatable around the vertical axis by the rotation mechanism 131 .

A peripheral edge removal portion 140 for removing the peripheral edge portion We of the wafer W to be processed is provided on the side of the suction cup 130 . The peripheral edge removal part 140 strikes the peripheral edge part We and removes the peripheral edge part We. The peripheral edge removal part 140 is equipped with a wedge roller 141 and a support roller 142.

The wedge roller 141 has a wedge shape with a pointed front end when viewed from the side. The wedge roller 141 is inserted from the outer end of the wafer W to be processed and the supporting wafer S to the interface between the wafer W to be processed and the supporting wafer S. Then, the peripheral portion We is pushed upward by the inserted wedge roller 141, and is separated and removed from the wafer W to be processed.

The support roller 142 penetrates the center of the wedge roller 141 and supports the wedge roller 141 . The support roller 142 is configured to be arbitrarily movable in the horizontal direction by a moving mechanism (not shown). When the support roller 142 moves, the wedge roller 141 also moves. In addition, the support roller 142 is configured to be arbitrarily rotatable around the vertical axis. When the support roller 142 rotates, the wedge roller 141 also rotates. In addition, in this embodiment, the support roller 142 is a so-called free roller that is rotated by the rotation of the suction cup 130 as will be described later. However, the support roller 142 can also be actively rotated by a rotating mechanism (not shown).

In addition, in this embodiment, although the wedge roller 141 is used as an insertion member, the insertion member is not limited to this form. For example, the insertion member may have a shape in which the width becomes smaller toward the radially outer side in side view, and a knife-shaped insertion member with a sharp front end may be used.

Nozzles 150 and 151 for supplying cleaning liquid to the wafer W to be processed are respectively provided above and below the suction cup 130 . Cleaning fluid, such as pure water. When the peripheral edge portion We is impacted by the peripheral edge removal portion 140 and the peripheral edge portion We is removed, dust (particles) is generated along with the removal. Therefore, in this embodiment, the cleaning liquid is supplied from the nozzles 150 and 151 to suppress the scattering of dust.

The upper nozzle 150 is arranged above the suction cup 130 and supplies the cleaning liquid from above the wafer W to be processed to the back surface Wb. The cleaning liquid from the upper nozzle 150 can suppress the scattering of dust that occurs when the peripheral portion We is removed, and can further suppress the scattering of dust onto the wafer W to be processed. Specifically, the cleaning liquid causes the dust to flow toward the outer peripheral side of the wafer W to be processed. In addition, the lower nozzle 151 is arranged below the suction cup 130 and supplies the cleaning liquid to the wafer W to be processed from the side of the supporting wafer S. By using the cleaning fluid from the lower nozzle 151, dust scattering can be suppressed more reliably. In addition, the cleaning liquid from the lower nozzle 151 can prevent dust or debris from the peripheral portion We from flowing back to the supporting wafer S side.

In addition, the number and arrangement of the nozzles 150 and 151 are not limited to this embodiment. For example, a plurality of nozzles 150 and 151 may be provided respectively. Furthermore, the lower nozzle 151 may be omitted.

In addition, the method of suppressing the scattering of dust is not limited to the supply of cleaning fluid. For example, a suction mechanism (not shown) may also be provided to suction and remove the generated dust.

A detection portion 160 is provided above the suction cup 130 for confirming whether the peripheral portion We has been removed from the wafer W to be processed. The detection unit 160 detects the presence or absence of the peripheral portion We in the wafer W to be processed, which is held by the suction cup 130 and has the peripheral portion We removed. The detection unit 160 uses, for example, a sensor. The sensor, for example, a linear laser displacement meter, irradiates the peripheral portion of the overlapping wafer T (the wafer to be processed W) with a laser, measures the thickness of the overlapping wafer T, and detects the thickness of the peripheral portion We. Yes or no. In addition, the method of detecting the presence or absence of the peripheral edge portion We by the detection unit 160 is not limited to this form. For example, the detection unit 160 may use a line camera to photograph the overlapping wafer T (the wafer to be processed W), thereby detecting the presence or absence of the peripheral edge portion We.

In addition, a recovery portion (not shown) is provided below the suction cup 130 to recover the peripheral edge portion We removed by the peripheral edge removal portion 140 .

Next, the transfer arm 71 of the wafer transfer device 70 will be described. FIG. 9 is a longitudinal sectional view showing an outline of the structure of the transfer arm 71 .

The transfer arm 71 has a larger diameter than the stacked wafer T, and is equipped with a disk-shaped suction plate 170 . A holding portion 180 is provided on the bottom surface of the suction plate 170 , and the holding portion 180 holds the central portion Wc of the wafer W to be processed.

The holding part 180 is connected to a suction pipe 181 that suctions the central part Wc, and the suction pipe 181 is connected to a suction mechanism 182 such as a vacuum pump. The suction pipe 181 is provided with a pressure sensor 183 for measuring suction pressure. The pressure sensor 183 may have any structure, and for example, a diaphragm type pressure gauge may be used.

On the top surface of the adsorption plate 170, a rotation mechanism 190 for rotating the adsorption plate 170 around a vertical axis is provided. The rotating mechanism 190 is supported on the supporting member 191. In addition, the support member 191 (rotation mechanism 190) is supported by the arm member 72.

Next, wafer processing performed using the wafer processing system 1 configured as described above will be described. Figure 10 is a flow chart showing the main steps of wafer processing. Figure 11 is an explanatory diagram of the main steps of wafer processing. In addition, in this embodiment, in a bonding device (not shown) outside the wafer processing system 1, the wafer to be processed W and the supporting wafer S are bonded to form an overlapping wafer T in advance.

First, the wafer cassette Ct containing a plurality of stacked wafers T shown in FIG. 11(a) is placed on the wafer cassette mounting table 10 of the loading and unloading station 2 .

Next, the overlapping wafer T in the wafer cassette Ct is taken out by the wafer transfer device 20 and transferred to the transfer device 30 . Then, the overlapping wafer T from the transfer device 30 is taken out by the wafer transfer device 50 and transferred to the modification device 60 . In the modification device 60, as shown in FIG. 11(b), the peripheral modification layer M1 and the segmentation modification layer M2 are sequentially formed inside the wafer W to be processed (steps A1 and A2 in FIG. 10). Further, as shown in FIG. As shown in 11(c), the internal surface modification layer M3 is formed (step A3 in Figure 10). The peripheral modified layer M1 serves as a base point for removing the peripheral portion We during peripheral trimming. The modified layer M2 is divided into base points for breaking the removed peripheral portion We into small pieces. The internal surface modification layer M3 becomes the base point for thinning the wafer W to be processed.

FIG. 12 is a flowchart showing the main steps of the reforming process of the reforming device 60 . Figure 13 is an explanatory diagram of the main steps of the modification process. In this embodiment, as shown in FIG. 13 , the suction cup 100 is arranged at the first position P1 and the second position P2, and each process is performed.

Before loading the stacked wafer T, the modifying device 60 moves the suction cup 100 (sliding table 102) to the first position P1 as shown in FIG. 13(a) and makes it standby. When the suction cup 100 is on standby, the power meter 107 is disposed below the lens 111 of the laser head 110 . The power meter 107 measures the output (power) of the laser light irradiated from the laser head 110 . The power of the laser light measured by the power meter 107 is output to the control device 90, and power confirmation is performed in the control device 90. In addition, while the suction cup 100 is on standby, the optical system of the laser head 110 is also calibrated (step B1 in FIG. 12 ).

Here, for example, when the power meter 107 is located far away from the first position P1, in order to confirm the power, the suction cup 100 must be moved from the first position P1, and the device becomes larger. On the other hand, in this embodiment, since the power meter 107 is disposed below the laser head 110 in the first position P1, power confirmation can be performed without moving the suction cup 100. As a result, the dedicated area (bottom area) of the reforming device 60 can be reduced, thereby saving space. In addition, power confirmation and calibration can be performed while the suction cup 100 is in standby, so the modification processing time can be shortened and the throughput of wafer processing can be increased. In addition, power confirmation and calibration can also be performed when loading the stacked wafer T in step B2 described below.

Next, as shown in FIG. 13( b ), with the suction cup 100 arranged at the first position, the stacked wafer T is loaded from the wafer transfer device 50 (step B2 in FIG. 12 ). The loaded overlapping wafer T is held on the suction cup 100 .

Next, with the suction cup 100 disposed at the first position P1, macro alignment is performed using the macro camera 121. At the first position P1, the macro camera 121 is disposed at a position capable of photographing the outer end of the wafer W to be processed. Then, after macro adjustment and focus adjustment of the macro camera 121 (step B3 in FIG. 12 ), the outer end of the wafer W to be processed is photographed (step B4 in FIG. 12 ).

First, in step B3, focus adjustment of the macro camera 121 is performed on a plurality of points in the height direction of the wafer W to be processed. At this time, the suction cup 100 is not rotated. Then, the macro camera 121 is raised or lowered by the lifting mechanism 123, and the focus adjustment of the macro camera 121 is performed at multiple points in the height direction of the wafer W to be processed.

The focus adjustment of this embodiment will be explained. FIG. 14 is an explanatory diagram showing the timing of focus adjustment relative to the elevation and lowering of the macro camera 121. The vertical axis represents the elevation speed and the horizontal axis represents time. In addition, Q1 to Q4 in Figure 14 represent the first to fourth focus adjustments respectively. In addition, (a) in FIG. 14 shows a comparative example, and (b) shows an example of this embodiment.

As shown in FIG. 14(a) , in the comparative example, after the macro camera 121 is raised and lowered, and then stopped at a predetermined height, focus adjustments Q1 to Q4 are performed. That is, every time the macro camera 121 is raised or lowered, acceleration and deceleration are repeated. Then, adjust each focus Q1 to Q4 to determine whether the focus value is appropriate. Therefore, time consuming.

On the other hand, as shown in FIG. 14(b) , in this embodiment, the macro camera 121 is raised and lowered to perform focus adjustments Q1 to Q4. That is, the macro camera 121 is not stopped when performing focus adjustment. Therefore, there is no need for acceleration and deceleration in the comparative example, thereby saving time, and further enabling an overall judgment as to whether the focus values of the focus adjustments Q1 to Q4 are appropriate. Therefore, the time for focus adjustment can be shortened. In addition, in the example of Figure 14, the time that can be shortened is t1.

Next, in step B4, the outer end portion of the wafer W to be processed is photographed at a plurality of points in the circumferential direction of the wafer W to be processed. At this time, the macro camera 121 is fixed without being raised, lowered or moved. Then, the suction cup 100 is rotated, and the outer end portion R1 of the wafer W to be processed is photographed at multiple points in the circumferential direction of the wafer W to be processed (dotted lines in FIG. 15 ) as shown in FIG. 15 .

When photographing the outer end of the wafer W to be processed, similarly to the focus adjustment shown in FIG. 14 , in the comparative example, the suction cup 100 is rotated and then photographed while stopping at a predetermined position. On the other hand, in this embodiment, the suction cup 100 is rotated and the outer end portion of the wafer W to be processed is photographed. That is, when shooting is performed, the rotation of the suction cup 100 is not stopped. Therefore, the shooting time can be shortened. In addition, if the shooting time is shortened in this way, the number of shots can also be increased. As a result, macro adjustment can be appropriately performed.

In this way, the macro camera 121 captures an image of the 360-degree outer end portion of the wafer W to be processed in the circumferential direction. The captured image is output from the macro camera 121 to the control device 90 .

The control device 90 calculates the first eccentricity amount between the center Cc of the chuck 100 and the center Cw of the wafer W to be processed from the image of the macro camera 121 . Furthermore, the control device 90 calculates the movement amount of the suction cup 100 based on the first eccentricity amount in order to correct the Y-axis component of the first eccentricity amount. The suction cup 100 moves in the Y-axis direction based on the calculated movement amount, so that the suction cup 100 moves to the super macro alignment position. The ultra-macro alignment position is a position where the ultra-macro camera 122 can image the peripheral portion of the wafer W to be processed. Here, as mentioned above, the field of view of the super macro camera 122 is a small range of about 1/5 compared to the macro camera 121. Therefore, if the Y-axis component of the first eccentricity is not corrected, the peripheral edge of the wafer W to be processed will be Part of the image does not enter the field of view of the ultra-macro camera 122 and cannot be photographed by the ultra-macro camera 122 . Therefore, it can also be said that the correction based on the Y-axis component of the first eccentricity is to move the suction cup 100 to the ultra-macro alignment position.

In addition, in the macro adjustment using the macro camera 121, the light amount is also adjusted before the focus adjustment. The light amount adjustment can be performed for each stacked wafer T, or for each batch, or for each processing condition (processing recipe). The light amount adjustment can be performed on one point or a plurality of points on the wafer W to be processed. However, in this case, the rotation of the suction cup 100 is stopped and the light amount adjustment is performed. In addition, while the rotation of the suction cup 100 is stopped, the light intensity is changed several times to perform photography.

In addition, as mentioned above, macro adjustment is performed to move the suction cup 100 to the super macro adjustment position, but this macro adjustment can be omitted. That is, in the case where the adjustment is not performed in the two stages of macro and super macro, but is performed in only one stage of super macro, macro adjustment is omitted.

Next, as shown in Fig. 13(c), the suction cup 100 is moved to the second position P2 (step B5 in Fig. 12).

Next, with the suction cup 100 disposed at the second position P2, super macro alignment is performed using the super macro camera 122. At the second position P2, the ultra-macro camera 122 is disposed at a position capable of photographing the boundary between the bonded area Aa and the unbonded area Ab of the wafer W to be processed. Then, after super macro adjustment and focus adjustment of the super macro camera 122 (step B6 in FIG. 12 ), the boundary between the joint area Aa and the unjoined area Ab is photographed (step B7 in FIG. 12 ).

First, in step B6, focus adjustment of the ultra-macro camera 122 is performed on a plurality of points in the height direction of the wafer W to be processed. The focus adjustment of the super macro camera 122 is performed by raising and lowering the super macro camera 122 through the lifting mechanism 123 . Therefore, the time for focus adjustment can be shortened. In addition, the focus adjustment of the super macro camera 122 is the same as the focus adjustment of the macro camera 121 in step B3, so the description is omitted.

Next, in step B7, the boundary between the bonded area Aa and the unbonded area Ab of the wafer W is photographed at a plurality of points in the circumferential direction of the wafer W to be processed. At this time, the macro camera 121 is fixed without being raised, lowered or moved. Then, the suction cup 100 is rotated, and the boundary R2 (dotted line in FIG. 16 ) between the bonded area Aa and the unbonded area Ab is photographed at multiple points in the circumferential direction of the wafer W to be processed, as shown in FIG. 16 .

In the photographing of the boundary between the bonded area Aa and the unbonded area Ab, similarly to the photographing of the outer end of the wafer W to be processed in step B3, in the comparative example, the suction cup 100 is rotated and then stopped at a predetermined position. The shooting was carried out under this condition. On the other hand, in this embodiment, the suction cup 100 is rotated and the boundary between the bonded area Aa and the unjoined area Ab is photographed. That is, when shooting is performed, the rotation of the suction cup 100 is not stopped. Therefore, the shooting time can be shortened. In addition, if the shooting time is shortened in this way, the number of shots can also be increased. As a result, super macro adjustment can be appropriately performed.

In this way, the ultra-macro camera 122 captures an image of the boundary between the bonded area Aa and the unbonded area Ab in the 360-degree circumferential direction of the wafer W to be processed. The captured image is output from the super macro camera 122 to the control device 90 .

The control device 90 calculates the second eccentricity amount between the center Cc of the suction cup 100 and the center Ca of the joint area Aa from the image of the super macro camera 122 . Furthermore, the control device 90 determines the position of the suction cup 100 relative to the peripheral modification layer M1 in such a manner that the center of the joint area Aa coincides with the center of the suction cup 100 based on the second eccentricity.

Next, with the suction cup 100 arranged at the second position P2, the height of the laser light irradiated from the laser head 110 is adjusted (irradiation height adjustment) (step B8 in FIG. 12). In the second position P2, the lens 111 of the laser head 110 is disposed at a position where the laser light can be irradiated to the boundary between the peripheral portion We and the central portion Wc of the wafer W to be processed.

Here, as will be described later, in step B9, the suction cup 100 is rotated, and the inside of the wafer W to be processed is irradiated with laser light from the laser head 110 to form an annular peripheral modified layer. In addition, in step B9, the irradiation position (irradiation height) of the laser light is measured, and the height of the laser light is adjusted (tracked) in real time. Therefore, the height of the starting position of laser light irradiation becomes important. Therefore, the laser light irradiation height adjustment in step B8 is performed at the laser light irradiation start position in step B9.

In addition, the height of the wafer W held by the chuck 100 may not be uniform within the wafer surface due to various factors. As a result, there may be a difference in height between the peripheral part and the center part of the wafer W to be processed. For example, if the height of the laser light is adjusted at the center of the wafer W to be processed, the peripheral part may not be appropriately adjusted. Therefore, from this point of view, the adjustment of the laser light irradiation height in step B8 is also suitable to be performed at the starting position of the laser light irradiation in step B9.

Furthermore, the sensor 113 used to measure the irradiation position of the laser light in step B9 has a limited tracking range. This range is, for example, starting from the back surface Wb of the wafer W to be processed, which is the measurement object, in the vertical direction. ±0.2mm. Therefore, in order to converge the irradiation position of the laser light in step B9 within the range that the sensor 113 can track, the irradiation height adjustment in step B8 must also be performed.

In step B8, first, the sensor 114 and the camera 115 are moved to the starting position of laser light irradiation in step B9. Then, the laser head 110 is raised and lowered, and the height of the back surface Wb of the wafer W to be processed at the starting position of laser light irradiation is measured by the sensor 114, and the back surface Wb is detected. The height of the back surface Wb measured by the sensor 114 is output to the control device 90 . The control device 90 detects (specifies) the position of the back surface Wb based on the height of the back surface Wb.

In step B8, the laser head 110 is then moved in the horizontal direction to the laser light irradiation position in step B9. Then, with the camera 115, the back Wb is photographed. The image of the back surface Wb captured by the camera 115 is output to the control device 90 . The control device 90 calculates the height of the back surface Wb based on the image of the back surface Wb, and further calculates the irradiation position of the laser light irradiated into the inside of the wafer W to be processed based on the height of the back surface Wb. Then, the laser head 110 is lowered and placed at the irradiation height of the laser light, and the calculated position is set to the origin position of the laser light irradiation position for the sensor 113 (zero point adjustment). In this way, in step B8, after roughly detecting the back surface Wb with the sensor 114, the back surface Wb is grasped in detail with the camera 115, and zero point adjustment is performed.

In addition, in step B8, the laser head 110 is raised or lowered, and the sensor 114 and the camera 115 are used to perform zero point adjustment. Here, similar to the focus adjustment shown in FIG. 14 above, after stopping the lifting and lowering of the laser head 110, and in a state of stopping at a predetermined height, the height of the back surface Wb is measured by the sensor 114. The zero point adjustment is time-consuming. time. On the other hand, in this embodiment, the laser head 110 is raised and lowered, and the measurement by the sensor 114 is performed. That is, when the measurement by the sensor 114 is performed, the lifting and lowering of the laser head 110 is not stopped. Therefore, the time for zero point adjustment can be shortened. Similarly, when the camera 115 takes a picture of the back surface Wb, it is performed in a state of stopping the laser head 110 at a predetermined height after the lifting and lowering of the laser head 110. Therefore, zero-point adjustment takes time. In contrast, by raising and lowering the laser head 110 and photographing the back surface Wb by the camera 115, the time for zero point adjustment can be shortened.

Then, the sensor 113 is moved to the starting position of laser light irradiation. Thereafter, as shown in FIGS. 17 and 18 , laser light L1 (peripheral laser light L1 ) is irradiated from the laser head 110 to form a peripheral modified layer at the boundary between the peripheral portion We and the central portion Wc of the wafer W to be processed. M1 (Step B9 in Figure 12, Step A1 in Figure 10). A plurality of peripheral modified layers M1 are formed at different heights. In addition, the peripheral modified layer M1 is formed radially inward of the outer end of the bonding area Aa.

The above-mentioned peripheral modification layer M1 formed by the laser light L1 extends in the thickness direction and has a longitudinally long aspect ratio. The lower end of the lowermost peripheral modification layer M1 is located above the target surface of the thinned wafer W (the dotted line in FIG. 17 ). That is, the distance H1 between the lower end of the peripheral modification layer M1 and the surface Wa of the wafer W to be processed is larger than the target thickness H2 of the wafer W to be processed after thinning. In this case, no peripheral modification layer M1 is left on the processed wafer W after thinning. In addition, inside the processed wafer W, the crack C1 develops from the plurality of peripheral modified layers M1 and reaches the back surface Wb and the surface Wa.

In step B9, the suction cup 100 is rotated by the rotating mechanism 103, and at the same time, the suction cup 100 is moved in the Y-axis direction by the moving mechanism 104, so as to align the position of the suction cup 100 determined by the control device 90, so that the center of the joint area Aa and The centers of the suction cups 100 are consistent. At this time, the rotation of the suction cup 100 is synchronized with the movement in the Y-axis direction.

Then, the suction cup 100 (the wafer W to be processed) is rotated and moved in this way, and the inside of the wafer W to be processed is irradiated with the laser light L1 from the laser head 110 . That is, the second eccentricity calculated in step B7 is corrected, and the peripheral modified layer M1 is formed. In this way, the peripheral modified layer M1 is formed into an annular shape concentrically with the joint area Aa. Therefore, thereafter, in the peripheral edge removal device 61, the peripheral edge portion We can be appropriately removed using the peripheral edge modified layer M1 as a base point.

In addition, in this example, when the second eccentricity has an X-axis component, the suction cup 100 is moved in the Y-axis direction and rotated to correct the X-axis component. On the other hand, when the second eccentricity does not have an X-axis component, the suction cup 100 may only be moved in the Y-axis direction without rotating it.

In addition, at the second position P2, the ultra-macro camera 122 is arranged on the positive Y-axis direction side with respect to the wafer W held on the chuck 100, and the lens 111 of the laser head 110 is arranged on the negative Y-axis direction side. In this case, in step B9, the peripheral modified layer M1 is formed by the laser head 110, and at the same time, the peripheral modified layer M1 is photographed by the super macro camera 122. The captured image is output to the control device 90, and it is checked in the control device 90 whether the peripheral modified layer M1 is formed at an appropriate position. In this way, by performing the formation and inspection of the peripheral modified layer M1 in parallel, the work efficiency can be improved. In addition, as a result of the inspection, if the peripheral modified layer M1 deviates from the predetermined position, the movement of the suction cup 100 can also be finely adjusted.

In this way, while the inside of the wafer W to be processed is irradiated with the laser light L1 to form the peripheral edge modification layer M1, the height of the back surface Wb of the wafer to be processed W is measured by the sensor 113, and the height of the back surface Wb of the wafer to be processed W is further measured by the control device 90 Calculate the irradiation position of laser light L1. Then, control is performed so that the calculated irradiation position of the laser light L1 coincides with the origin position set in step B8. Specifically, the lens 111 is raised and lowered by the piezoelectric actuator 112 based on the calculated irradiation position of the laser light L1. In this way, in step B9, the height of the tracking laser light L1 is adjusted in real time.

Here, the sensor 113 is provided coaxially with the laser light L1 irradiated from the lens 111 . Depending on the processing recipe of step B9, the irradiation radius of the laser light L1 (the radius of the peripheral modification layer) may be different. In this case, if the sensor 113 is disposed coaxially with the laser light L1, the sensor 113 measures the back surface Wb of the wafer W to be processed at a position different from the position where the laser light L1 is irradiated. height, and may deviate from the actual height. Therefore, in this embodiment, the sensor 113 is installed coaxially with the laser light L1.

In step B9, as described above, the inside of the wafer W to be processed is irradiated with a circle of laser light L1, thereby forming one layer of peripheral modification layer M1. Then, when forming a plurality of peripheral modified layers M1 at different heights like this embodiment, the irradiation position (irradiation height) of the laser light L1 is changed. Hereinafter, the method of forming the plurality of peripheral modified layers M1 in this embodiment will be described.

FIG. 19 is an explanatory diagram illustrating a method of forming a plurality of peripheral modified layers M1. The vertical axis represents rotation speed and the horizontal axis represents time. In addition, L1 in FIG. 19 represents the irradiation of the laser light L1, and D represents the change of the processing conditions (processing recipe) when forming the peripheral modification layer M1. The processing condition change D includes: raising and lowering the lens 111 to change the irradiation position of the laser light L1; and changing the conditions of the laser light L1, such as the output (power), frequency, shape (laser pattern), number of branches, etc. of the laser light L1. . In addition, (a) in FIG. 19 shows a comparative example, and (b) shows an example of this embodiment.

As shown in FIG. 19(a) , in the comparative example, after the rotation of the suction cup 100 is accelerated, the laser light L1 is irradiated for one turn while maintaining a constant speed to form one peripheral modification layer M1. Thereafter, after decelerating the rotation of the suction cup 100 and stopping the rotation, process condition change D is performed. That is, each time one peripheral modified layer M1 is formed, the process condition change D is performed. Every time processing condition change D is performed, the acceleration and deceleration of the rotation of the suction cup 100 is repeated. Therefore, time consuming.

On the other hand, as shown in FIG. 19(b) , in this embodiment, the suction cup 100 is rotated, and the processing condition change D of the peripheral modified layer M1 is performed. That is, when processing condition change D is performed, the rotation of the suction cup 100 is not stopped. Therefore, there is no need to accelerate and decelerate the rotation of the suction cup 100 in the comparative example, thereby saving time. Therefore, the time required to form the plurality of peripheral modified layers M1 can be shortened. In addition, in the example of Figure 19, the time that can be shortened is t2. In addition, if the time for forming the plurality of peripheral modified layers M1 is shortened in this way, the number of peripheral modified layers M1 formed can also be increased.

In addition, when the irradiation of the laser light L1 and the processing condition D of the peripheral modification layer M1 are continuously performed as shown in FIG. 19(b), when one layer of the peripheral modification layer M1 is formed as shown in FIG. 20 The irradiation start position and the irradiation end position of the laser light L1 are respectively shifted in the circumferential direction.

On the other hand, as shown in FIG. 21 , the irradiation start position and the irradiation end position of the laser light L1 when forming one layer of peripheral modification layer M1 may be the same. Then, after the processing condition change D of the peripheral modification layer M1 is implemented, the laser light L1 is not irradiated until the lens 111 is located above the irradiation start position of the laser light L1. In this case, also when the process condition change D is performed, the rotation of the suction cup 100 is not stopped, and the time required to form the plurality of peripheral modified layers M1 can be shortened.

In addition, in the example shown in FIG. 19 , the case where the processing conditions are changed for each peripheral modified layer M1 when forming a plurality of peripheral modified layers M1 is explained. However, there is also a case where one peripheral modified layer M1 is formed. time, that is, the condition of the laser light L1 is changed during one revolution of the laser light L1. For example, in the wafer W to be processed, the conditions of the laser light L1 may be changed according to the crystal orientation of silicon. FIG. 22 is an explanatory diagram showing an example of changing the conditions of the laser light L1 during one revolution. In the example shown in FIG. 22 , the wafer W to be processed is divided into four parts, the diagonal wafers W1 and W1 are irradiated with laser light L1 under one condition, and the wafers W2 and W2 are irradiated with laser light under another condition. Shoot light L1.

When performing the processing shown in FIG. 22 , in the comparative example, while the suction cup 100 is rotating, the laser light L1 is irradiated on the wafers W1 and W1 in the first turn, and the wafers W2 and W2 are stopped. Irradiation of laser light L1. Thereafter, while first stopping the rotation of the suction cup 100, the conditions of the laser light L1 are changed. Then, while the suction cup 100 is rotated again, the wafers W2 and W2 to be processed are irradiated with the laser light L1 in the second rotation, and the wafers W1 and W1 are irradiated with the laser light L1. In this case, it takes time because the rotation of the suction cup 100 is accelerated and decelerated when changing the conditions of the laser light L1.

On the other hand, in this embodiment, the suction cup 100 is rotated and the conditions of the laser light L1 are changed. That is, when the conditions of the laser light L1 are changed, the rotation of the suction cup 100 is not stopped. Therefore, there is no need to accelerate and decelerate the rotation of the suction cup 100 in the comparative example, thereby saving time. Therefore, the time required to form the peripheral modified layer M1 can be shortened.

Here, as shown in FIG. 23 , a notch Wn is formed on the outer edge of the wafer W to be processed. For example, as shown in FIG. 23(a) , when the formation position of the peripheral modified layer M1 overlaps with the notch Wn, the laser light L1 is irradiated to the notch Wn. In this way, in the end portion of the notch portion Wn, the cross section irradiated with the laser light L1 is roughened. In addition, as described above, in step B9, when the suction cup 100 is rotated and the laser light L1 is irradiated, the irradiation position (irradiation height) of the laser light L1 is adjusted (tracked) in real time. At this point, when the laser light L1 is irradiated to the notch portion Wn, the irradiation position of the laser light L1 changes. As a result, it takes time to immediately adjust the irradiation position of the laser light L1 outside the notch portion Wn.

Therefore, in this embodiment, in step B9, as shown in FIG. 23(b), it is controlled so that the laser light L1 does not irradiate the notch part Wn. Since the position of the notch Wn of the wafer W to be processed is known in advance, when the lens 111 of the laser head 110 is disposed above the notch Wn, the irradiation of the laser light L1 can be stopped. In this case, the laser light L1 does not irradiate the notch part Wn, so the end section of the notch part Wn is not roughened. In addition, in the notch portion Wn, real-time adjustment of the irradiation position of the laser light L1 is stopped. In this way, during the irradiation of a circle of laser light L1, the irradiation position of the laser light L1 does not change significantly, and real-time adjustment outside the notch portion Wn becomes simple.

If the peripheral modified layer M1 is formed as described above, then, as shown in FIGS. 24 and 25 , laser light L2 (segmentation laser light L2) is irradiated from the laser head 110 to form the peripheral modified layer M1 on the radially outer side. The modified layer M2 is divided (step B10 in Figure 12, step A2 in Figure 10).

The divided modified layer M2 also extends in the thickness direction like the peripheral modified layer M1 and has a longitudinally long aspect ratio. In addition, the crack C2 develops from the divided modified layer M2 and reaches the back surface Wb and the surface Wa.

In addition, by forming a plurality of divided modified layers M2 and cracks C2 at intervals of several μm in the radial direction, as shown in FIG. 25 , a divided line extending from the peripheral modified layer M1 toward the radially outer side is formed. Modified layer M2. In addition, in the example shown in the figure, the divided modified layers M2 along the lines extending in the radial direction are formed at eight places, but the number of the divided modified layers M2 can be any number. If the divided modified layer M2 is formed in at least two places, the peripheral portion We can be removed. In this case, when the peripheral portion We is removed during peripheral trimming, the peripheral portion We is separated based on the annular peripheral modified layer M1 and is divided into plural pieces by dividing the modified layer M2. In this way, the removed peripheral portion is reduced into small pieces, making it easier to remove.

Here, in the comparative example, as shown in FIG. 26 , the suction cup 100 is moved in the Y-axis direction to form the divided modified layer M2. That is, as shown in FIG. 26(a) , from the state where the suction cup 100 is located on the positive Y-axis direction side of the lens 111, as shown in FIG. 26(b) , the suction cup 100 is moved in the negative Y-axis direction. Then, when the wafer W to be processed passes under the lens 111, one end of the peripheral portion We is irradiated with the laser light L2 to form the divided modified layer M21. Thereafter, as shown in FIG. 26(c) , the suction cup 100 is further moved in the negative direction of the Y-axis, and the divided modified layer M22 is formed on the other end of the peripheral portion We. In this way, the divided modified layers M21 and M22 are formed on the opposing peripheral edge portions We. In this case, the movement distance D1 of the suction cup 100 becomes longer. Specifically, the movement distance D1 requires, for example, one piece of the wafer W to be processed, a distance for acceleration and a distance for deceleration from the suction cup 100 .

In contrast, in step B10 of this embodiment, as shown in FIG. 27 , the divided modified layer M2 is formed only on one end of the peripheral portion We, and the suction cup 100 is further rotated, thereby shortening the moving distance of the suction cup 100 . That is, as shown in FIG. 27(a) , from the state where the suction cup 100 is located on the positive Y-axis direction side of the lens 111 , the suction cup 100 is moved in the negative Y-axis direction as shown in FIG. 27(b) . Then, when the wafer W to be processed passes under the lens 111, one end (a circumferential position) of the peripheral portion We is irradiated with the laser light L2 to form the divided modified layer M21. Next, as shown in FIG. 27(c) , the suction cup 100 is rotated 180 degrees. Thereafter, as shown in FIG. 27(d) , the suction cup 100 is moved in the positive direction of the Y-axis, and the divided modified layer M22 is formed at the other end of the peripheral portion We (the other circumferential position). In this case, the moving distance D2 of the suction cup 100 becomes shorter. Specifically, the movement distance D2 may be, for example, only a formation width of the divided modified layer M2, a distance for acceleration and a distance for deceleration from the suction cup 100.

In this way, in this embodiment, when forming the divided modified layer M2 in step B10, the moving distance of the suction cup 100 is shortened, thereby reducing the occupied area (bottom area) of the modifying device 60 and saving space.

In addition, in this embodiment, when forming the divided modified layer M2, the suction cup 100 is moved in the Y-axis direction, but the laser head 110 may also be moved in the Y-axis direction.

Next, as shown in FIGS. 28 and 29 , laser light L3 (inner surface laser light L3 ) is irradiated from the laser head 110 to form the inner surface modification layer M3 along the surface direction (step B11 in FIG. 12 and step B10 in FIG. 10 Step A3). In addition, the black arrow shown in FIG. 29 indicates the rotation direction of the suction cup 100, and the same applies to the following description.

The lower end of the inner surface modification layer M3 is located slightly above the target surface of the thinned wafer W (the dotted line in Figure 28). That is, the distance H3 between the lower end of the inner surface modification layer M3 and the surface Wa of the wafer W to be processed is slightly larger than the target thickness H2 of the wafer W to be processed after thinning. In addition, inside the wafer W to be processed, the crack C3 develops from the inner surface modification layer M3 toward the surface direction.

In step B11, the suction cup 100 (the wafer to be processed W) is rotated, and the laser head 110 is moved in the Y-axis direction from the outer peripheral portion toward the center of the wafer to be processed W, and the laser head 110 moves the wafer to be processed W from the laser head 110. The inside of circle W is irradiated with laser light L3. In this way, the internal surface modification layer M3 is formed in a spiral shape from the outside to the inside of the surface of the wafer W to be processed.

In addition, in this embodiment, when forming the inner surface modification layer M3, the laser head 110 is moved in the Y-axis direction, but the suction cup 100 may also be moved in the Y-axis direction. In addition, when forming the inner surface modification layer M3, the suction cup 100 is rotated, but the laser head 110 may also be moved so that the laser head 110 rotates relative to the suction cup 100.

Next, as shown in FIG. 13(d) , the suction cup 100 is moved to the first position P1 (step B12 in FIG. 12 ). Thereafter, the stacked wafer T is carried out from the first position P1 by the wafer transport device 70 (step B13 in FIG. 12 ).

The above is a series of processes performed by the reforming device 60 . Next, returning to FIGS. 10 and 11 , the wafer processing performed by the wafer processing system 1 will be described.

The stacked wafer T carried out from the modifying device 60 is then transported to the peripheral edge removal device 61 by the wafer transport device 70 . In the peripheral edge removal device 61, as shown in FIG. 11(d), the peripheral edge portion We of the wafer W to be processed is removed based on the peripheral edge modification layer M1 (step A4 in FIG. 10). In step A4, as shown in FIG. 8 , the wedge roller 141 is inserted from the outer end of the wafer W to be processed and the supporting wafer S to the interface between the wafer W to be processed and the supporting wafer S. Then, the peripheral edge portion We is pushed upward by the inserted wedge roller 141, and is separated and removed from the wafer W to be processed using the peripheral edge modified layer M1 as a base point. At this time, using the divided modified layer M2 as a base point, the peripheral portion We is divided into small pieces and separated. In addition, the removed peripheral edge portion We is recovered to a recovery unit (not shown).

Next, the stacked wafer T is transported to the processing device 80 by the wafer transport device 70 . In the processing device 80 , first, the stacked wafer T is transferred from the transfer arm 71 to the suction cup 83 at the transfer position A0 . At this time, as shown in FIG. 11(e) , the back surface Wb side of the wafer W to be processed (hereinafter referred to as the back surface wafer Wb1 ) is separated using the inner surface modification layer M3 as a base point (step A5 in FIG. 10 ).

In step A5 , the wafer W to be processed is sucked and held by the suction plate 170 of the transport arm 71 , and the supporting wafer S is sucked and held by the suction cup 83 . Then, the suction plate 170 is rotated to detach the backside wafer Wb1 with the inner surface modification layer M3 as a boundary. Thereafter, with the adsorption plate 170 adsorbing and holding the backside wafer Wb1, the adsorption plate 170 is raised to separate the backside wafer Wb1 from the wafer W to be processed. At this time, by measuring the pressure of sucking the backside wafer Wb1 with the pressure sensor 183, the presence or absence of the backside wafer Wb1 can be detected, and it can be confirmed whether the backside wafer Wb1 has been separated from the wafer W to be processed. In addition, the separated backside wafer Wb1 is recovered outside the wafer processing system 1 .

Then, the suction cup 83 is moved to the processing position A1. Thereafter, the back surface Wb of the wafer W to be processed held on the suction cup 83 is polished by the polishing unit 84, as shown in FIG. The mass layer M1 is removed (step A6 in Figure 10). In step A6, with the grinding wheel in contact with the back surface Wb, the wafer W to be processed and the grinding wheel are rotated respectively to grind the back surface Wb. In addition, thereafter, a cleaning liquid nozzle (not shown) may also be used to clean the backside Wb of the wafer W to be processed with the cleaning liquid.

Next, the stacked wafer T is transported to the cleaning device 41 by the wafer transport device 70 . The cleaning device 41 brushes and cleans the back surface Wb, which is the polished surface of the wafer W to be processed (step A7 in FIG. 10 ). In addition, the cleaning device 41 can also clean the back surface Sb of the supporting wafer S and the back surface Wb of the wafer W to be processed together.

Next, the stacked wafer T is transported to the etching device 40 by the wafer transport device 50 . The etching device 40 wet-etches the back surface Wb of the wafer W to be processed using a chemical solution (step A8 in FIG. 5 ). Polishing marks may be formed on the back surface Wb polished by the above-mentioned processing device 80 . In this step A8, the grinding marks can be removed by wet etching, and the back surface Wb can be smoothed.

Thereafter, the stacked wafer T that has been subjected to all processes is transported to the conveyor 30 by the wafer transport device 50, and further transported to the wafer cassette of the wafer cassette mounting table 10 by the wafer transport device 20. Ct. In this way, a series of wafer processing by the wafer processing system 1 is completed.

According to the above embodiment, by optimizing the positions and processing contents of the components of the reforming device 60, the occupied area of the reforming device 60 can be reduced and space can be saved. In addition, along with this, the throughput of wafer processing can also be increased.

More specifically, in the reforming device 60, all processes can be performed by arranging the suction cup 100 at two positions: the first position P1 and the second position. That is, at the first position P1, the power confirmation and calibration of step B1, the loading and unloading of the overlapped wafer T in steps B2 and B12, and the macro alignment of steps B3 and B4 are performed. At the second position P2, the ultra-macro alignment of steps B6 and B7, the adjustment of the laser light irradiation height of step B8, the formation of the peripheral modification layer M1 of step B9, the formation of the divided modification layer M2 of step B10, and the formation of the inner surface modification layer M3 in step B11. In this way, the suction cup 100 only needs to move between the first position P1 and the second position P2, so the moving distance is shortened and the cost of controlling the movement of the suction cup 100 can be reduced.

In addition, when the suction cup 100 is arranged at the first position P1, the power meter 107 is arranged below the lens 111 of the laser head 110. For example, when the power meter 107 is located far away from the first position P1, it is necessary to move the suction cup 100 from the first position P1 in order to confirm the power. However, in this embodiment, such movement of the suction cup 100 is not required. Therefore, the area occupied by the reforming device 60 can be reduced, thereby saving space. In addition, in step B1, the power confirmation and calibration can be performed while the suction cup 100 is on standby, so the time of the modification process can be shortened and the throughput of the wafer processing can also be increased.

In addition, when forming the divided modified layer M2 in step B10, after forming the divided modified layer M21 at one end of the peripheral portion We, the suction cup 100 is rotated to form the divided modified layer M22 at the other end of the peripheral portion We. Therefore, the moving distance of the suction cup 100 can be shortened, and the occupied area of the reforming device 60 can be reduced, thereby saving space.

In addition, in the above embodiment, the peripheral edge portion We is removed by using the peripheral edge removing portion 140 in the peripheral edge removing device 61, but the removal method is not limited to this embodiment. For example, the peripheral portion We may be held and removed, or the peripheral portion We may be removed by applying physical impact or ultrasonic waves.

In addition, in the above-mentioned embodiment, the separation of the backside wafer Wb1 from the wafer W to be processed is performed when the overlapping wafer T is transferred from the transfer arm 71 of the wafer transfer device 70 to the suction cup 83 of the processing device 80. However, the separation The method is not limited to this form. For example, the separation device (not shown) and the peripheral edge removal device 61 may be provided in the same device, or the separation device (not shown) may be provided separately.

Furthermore, in the above embodiment, the thinning of the wafer W to be processed is performed by separating the backside wafer Wb1, but the thinning method is not limited to this embodiment. For example, the back surface Wb of the wafer W to be processed may also be polished, or the back surface Wb may be etched.

In addition, in the above-mentioned embodiment, the case where the to-be-processed system overlaps the wafer T has been described, but it is not limited to this embodiment. The object to be processed may be, for example, something other than a substrate. When the inside of the object to be processed is irradiated with laser light to form a modified layer, the above embodiment can be applied.

It should be understood that the embodiments disclosed this time are only illustrative in all respects, and do not limit the present invention. The above-described embodiments may be omitted, replaced, or modified in various forms without departing from the scope of the attached invention and its gist.

1: Wafer handling system 2: Move in and out 3: Processing station 10: Wafer cassette loading table 20:Wafer handling device 21:Portage road 22:Carrying arm 30:Transmission device 40:Etching device 41:Cleaning device 50:Wafer handling device 51:Carrying arm 60: Modification device 61: Perimeter removal device 70:Wafer handling device 71:Carrying arm 72:Arm member 80: Processing device 81: Rotary table 82: Rotation center line 83:Suction cup 84:Grinding unit 85:Grinding Department 86:Pillar 90:Control device 100:Suction cup 101:Air bearing 102:Sliding table 103: Rotating mechanism 104:Mobile mechanism 105:Orbit 106:Abutment 107:Power meter 110:Laser head 111:Lens 112: Piezoelectric actuator 113: Sensor 114: Sensor 115:Camera 116: Support components 117:Orbit 118:Lifting mechanism 119:Mobile mechanism 120:Support column 121:Macro camera 122:Super macro camera 123:Lifting mechanism 124:Mobile mechanism 130:Suction cup 131: Rotating mechanism 140: Peripheral removal part 141:Wedge roller 142:Support scroll wheel 150,151:Nozzle 160:Detection Department 170:Adsorption plate 180: Holding part 181:Suction tube 182:Suction mechanism 183: Pressure sensor 190: Rotating mechanism 191:Support components A0: Pass position A1: Processing position Aa: joint area Ab: unjoined area C1,C2,C3: cracks Ca,Cc,Cw: center Ct:wafer cassette D: Processing condition changes D1, D2: moving distance F:Oxide film G1~G3: processing blocks H: recording medium H1, H3: distance H2: target thickness L1, L2, L3: laser light M1: Peripheral modified layer M2, M21, M22: split modified layer M3: Internal surface modification layer P1: No. 1 position P2: 2nd position Q1~Q4: Focus adjustment R1: outer end R2: Boundary S:Support wafer Sa: Surface Sb: back T: Coincident wafer W, W1, W2: wafer to be processed Wa: surface Wb: back Wb1: Backside wafer Wc:Central Department We:peripheral part Wn: notch part

FIG. 1 is a plan view schematically illustrating the structure of the wafer processing system according to this embodiment. FIG. 2 is a side view showing an outline of the structure of a stacked wafer. FIG. 3 is a side view schematically showing the structure of a part of the stacked wafer. FIG. 4 is a plan view showing an outline of the structure of the reforming device. Fig. 5 is a side view showing an outline of the structure of the reforming device. FIG. 6 is a plan view showing an outline of the structure of the peripheral edge removing device. FIG. 7 is a side view schematically showing the structure of the peripheral edge removing device. FIG. 8 is an explanatory diagram schematically illustrating the structure of the peripheral edge removal device. FIG. 9 is a longitudinal sectional view showing an outline of the structure of the transfer arm. FIG. 10 is a flowchart showing the main steps of wafer processing in this embodiment. 11 (a) to (f) are explanatory diagrams of the main steps of wafer processing in this embodiment. Figure 12 is a flow chart showing the main steps of the modification process. Figures 13 (a) to (d) are explanatory diagrams of the main steps of the modification process. FIGS. 14(a) and 14(b) are explanatory diagrams showing the timing of focus adjustment relative to the lifting and lowering of the super macro camera. FIG. 15 is an explanatory diagram showing how a macro camera captures an outer end portion of a wafer to be processed. FIG. 16 is an explanatory diagram showing how a super macro camera captures the boundary between a bonded area and an unbonded area of a wafer being processed. FIG. 17 is an explanatory diagram showing how a peripheral modified layer is formed on a wafer to be processed. FIG. 18 is an explanatory diagram showing how a peripheral modified layer is formed on a wafer to be processed. 19(a) and (b) are explanatory diagrams illustrating a method of forming a plurality of peripheral modified layers. FIG. 20 is an explanatory diagram showing how a plurality of peripheral modified layers are formed. FIG. 21 is an explanatory diagram showing how a plurality of peripheral modified layers are formed. FIG. 22 is an explanatory diagram showing how a peripheral modified layer is formed. 23(a) and (b) are explanatory diagrams showing the periphery of the notch when the peripheral modified layer is formed on the wafer to be processed. FIG. 24 is an explanatory diagram showing how a divided modified layer is formed on a wafer to be processed. FIG. 25 is an explanatory diagram showing how a divided modified layer is formed on a wafer to be processed. 26(a) to (c) are explanatory diagrams showing how divided modified layers are formed in a comparative example. FIGS. 27(a) to 27(d) are explanatory diagrams showing the formation of divided modified layers in this embodiment. FIG. 28 is an explanatory diagram showing how an internal surface modification layer is formed on a wafer to be processed. FIG. 29 is an explanatory diagram showing how an internal surface modification layer is formed on a wafer to be processed.

100:Suction cup

102:Sliding table

107:Power meter

110:Laser head

111:Lens

121:Macro camera

122:Super macro camera

P1: No. 1 position

P2: 2nd position

W: Processed wafer

Claims (8)

A processing device used to process an object to be processed, including: a holding part to hold the object to be processed; a modifying part to irradiate the inside of the object to be processed held in the holding part with laser light to form a modified layer; and measure a part that measures the output of the laser light; a moving part that places the holding part at a first position where the object to be processed is moved in and out of the holding part, and a second position where the modified layer is formed by the modifying part and the control part controls the holding part, the modifying part, the measuring part and the moving part; the control part controls the holding part, the measuring part and the moving part so that the holding part moves in the When the first position is in standby, the output of the laser light is measured by the measuring part; the object to be processed is a superimposed substrate formed by joining the first substrate and the second substrate; the holding part holds the second substrate from the side The superimposed substrate and the modified portion are irradiated with the laser light along the boundary between the peripheral portion and the central portion of the first substrate to form the modified layer, that is, the peripheral modified layer. The processing device of claim 1, wherein the measuring part is provided on the holding part; and in the first position, the measuring part is arranged below the modifying part. For example, the processing device of claim item 1 or 2, wherein, It further includes: a first imaging part that photographs the outer end of the first substrate when the holding part is disposed at the first position; and a second imaging part that photographs the outer end of the first substrate when the holding part is disposed at the second position. The boundary between the bonding area where the first substrate and the second substrate are bonded and the unjoined area outside the bonding area. If the processing device of claim 1 or 2 further includes a rotating part that rotates the holding part; the modifying part, in the second position, is inside the first substrate held in the holding part, Laser light is irradiated radially outward from the peripheral modification layer to form a divided modification layer; the control part controls the holding part, the modification part, the moving part and the rotating part so as to be arranged in the modification part After the divided modified layer is formed at the circumferential position in a state above the circumferential position of the peripheral part, the holding part is rotated by the rotating part, and the modified part is arranged on the other side of the peripheral part. In the state above the circumferential position, the divided modified layer is formed at the other circumferential position. A processing method for processing an object to be processed, including the following steps: holding the object to be processed by a holding part; irradiating laser light from the modification part to the inside of the object to be processed held in the holding part to form modification layer; measuring the output of the laser light by the measuring part; and placing the holding part at a first position for carrying the object to be processed into and out of the holding part, and a first position for forming the modified layer by the modifying part. Move between 2 positions; When the holding part is waiting at the first position, the output of the laser light is measured by the measuring part; the object to be processed is a superimposed substrate formed by joining the first substrate and the second substrate; the holding part is from The second substrate side holds the overlapping substrate; the modified portion irradiates the inside of the first substrate with the laser light along the boundary between the peripheral portion and the central portion as the object of removal to form the modified layer, that is, the peripheral edge modified layer. The processing method of claim 5, wherein the measuring part is arranged on the holding part; and in the first position, the measuring part is arranged below the modifying part. The processing method of claim 5 or 6, wherein when the holding part is arranged at the first position, the outer end of the first substrate is photographed by the first imaging part; and the holding part is arranged at the second position At this time, the boundary between the bonding area connecting the first substrate and the second substrate and the unjoined area outside the bonding area is imaged by the second imaging unit. The processing method of claim 5 or 6, wherein, at the second position, the inside of the first substrate held in the holding part is irradiated with laser light from the peripheral modified layer toward the radially outer side to form Split the modified layer; in a state where the modified part is arranged above the circumferential position of the peripheral part, after the divided modified layer is formed at the circumferential position, the holding part is rotated, and the modified part is arranged The divided modified layer is formed at the other circumferential position in a state above the other circumferential position of the peripheral portion.

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