JPWO2020054504A1 - Processing system and processing method - Google Patents

Abstract

A processing system that processes an object to be processed, in which the modification device that forms an internal surface modification layer in the plane direction inside the object to be processed and the object to be processed are separated from the internal surface modification layer as a base point. The reforming device has a laser irradiation unit that irradiates a plurality of laser beams inside the processing target body, and a movement that relatively moves the laser irradiation unit and the processing target body. It has a mechanism, and the moving mechanism moves the plurality of laser beams from the laser irradiation unit relative to the processing target body to form the internal surface modification layer.

Description

The present disclosure relates to a processing system and a processing method.

Patent Document 1 discloses a method for manufacturing a laminated semiconductor device. In this manufacturing method, two or more semiconductor wafers are laminated to manufacture a laminated semiconductor device. At this time, each semiconductor wafer is laminated on another semiconductor wafer and then back-ground so as to have a desired thickness.

Japanese Unexamined Patent Publication No. 2012-69736

The technique according to the present disclosure efficiently thins the object to be processed.

One aspect of the present disclosure is a processing system for processing an object to be treated, wherein a modification device for forming an internal surface modification layer in the surface direction inside the object to be processed and the internal surface modification layer as a base point. The reforming device includes a separation device that separates the processing target body, and the reforming device includes a laser irradiation unit that irradiates a plurality of laser beams inside the processing target body, and the laser irradiation unit and the processing target body. The internal surface modification layer is provided with a moving mechanism for relatively moving the laser beam, and the moving mechanism moves the plurality of laser beams from the laser irradiation unit relative to the processing target body. To form.

According to the present disclosure, the processing target can be efficiently thinned.

It is a top view which shows the outline of the structure of the wafer processing system which concerns on this embodiment schematically. It is a side view which shows the outline of the structure of the polymerization wafer. It is a side view which shows the outline of the structure of a part of a polymerization wafer. It is a side view which shows the outline of the structure of the reformer. It is a side view which shows the outline of the structure of the separation device. It is a flow chart which shows the main process of the wafer processing which concerns on this Embodiment. It is explanatory drawing of the main process of the wafer processing which concerns on this embodiment. It is explanatory drawing which shows the mode that the peripheral reforming layer and the split reforming layer are formed on the processing wafer in a reforming apparatus. It is explanatory drawing which shows the mode that the peripheral reforming layer and the split reforming layer are formed on the processing wafer in a reforming apparatus. It is explanatory drawing which shows the state of removing the peripheral edge part of the processing wafer in the peripheral edge removal apparatus. It is explanatory drawing which shows the state of forming an internal surface reforming layer on a processed wafer in a reforming apparatus. It is explanatory drawing which shows the state of forming an internal surface reforming layer on a processed wafer in a reforming apparatus. It is explanatory drawing which shows the state of separating the back surface wafer from the processing wafer in the separation apparatus. It is a side view which shows the outline of the structure of the reformer which concerns on other embodiment. It is explanatory drawing which shows the state of forming the internal surface reforming layer on the processed wafer in the reforming apparatus of another embodiment. It is explanatory drawing which shows the state of forming the internal surface reforming layer on the processed wafer in the reforming apparatus of another embodiment. It is explanatory drawing which shows the state of forming the internal surface reforming layer on the processed wafer in the reforming apparatus of another embodiment. It is explanatory drawing which shows the state of forming the internal surface reforming layer on the processed wafer in the reforming apparatus of another embodiment. It is explanatory drawing which shows the state of forming the internal surface reforming layer on the processed wafer in the reforming apparatus of another embodiment. It is explanatory drawing which shows the state of forming the internal surface reforming layer on the processed wafer in the reforming apparatus of another embodiment. It is a side view which shows the outline of the structure of the separation apparatus which concerns on other embodiment. It is a side view which shows the outline of the structure of the separation apparatus which concerns on other embodiment. It is a flow chart which shows the main process of the wafer processing which concerns on other embodiment. It is explanatory drawing of the main process of the wafer processing which concerns on other embodiment. It is explanatory drawing which shows the mode that the peripheral reforming layer is formed on the processed wafer in the reforming apparatus of another embodiment. It is explanatory drawing of the main process of the wafer processing which concerns on other embodiment. It is a side view which shows the outline of the structure of the interface processing apparatus. It is explanatory drawing which shows the state of the support wafer in the main process of a wafer processing. It is a vertical cross-sectional view which shows the appearance that the peripheral modification layer was formed radially inward with respect to the end portion of an oxide film. It is a side view which shows the outline of the structure of the interface processing apparatus.

In the process of manufacturing a semiconductor device, for example, as in the method disclosed in Patent Document 1, a back surface of a semiconductor wafer (hereinafter referred to as a wafer) in which a device such as a plurality of electronic circuits is formed on the surface thereof is subjected to the back surface of the wafer. Wafers are thinned by grinding.

Grinding of the back surface of the wafer is performed, for example, by rotating the wafer and the grinding wheel in a state where the grinding wheel is in contact with the back surface, and further lowering the grinding wheel. In such a case, the grinding wheel wears and needs to be replaced regularly. Further, in the grinding process, it is necessary to use grinding water and treat the waste liquid thereof. Therefore, running cost is high. Therefore, there is room for improvement in the conventional wafer thinning process.

Normally, the peripheral edge of the wafer is chamfered, but when the back surface of the wafer is ground as described above, the peripheral edge of the wafer becomes a sharply pointed shape (so-called knife edge shape). Then, chipping occurs at the peripheral edge of the wafer, and the wafer may be damaged. Therefore, so-called edge trimming is performed in which the peripheral edge of the wafer is removed in advance before the grinding process. Then, for example, in the method disclosed in Patent Document 1, the peripheral edge portion of the wafer is partially ground or cut to perform this edge trimming.

The technique according to the present disclosure efficiently thins the wafer. Hereinafter, a wafer processing system as a processing system and a wafer processing method as a processing method according to the present embodiment will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

First, the configuration of the wafer processing system according to the present embodiment will be described. FIG. 1 is a plan view schematically showing an outline of the configuration of the wafer processing system 1.

In the wafer processing system 1, as shown in FIGS. 2 and 3, the polymerized wafer T as the processing target to which the processing wafer W and the support wafer S are joined is subjected to a desired processing to thin the processing wafer W. do. Hereinafter, in the processed wafer W, the surface bonded to the support wafer S is referred to as a front surface Wa, and the surface opposite to the front surface Wa is referred to as a back surface Wb. Similarly, in the support wafer S, the surface bonded to the processed wafer W is referred to as a front surface Sa, and the surface opposite to the front surface Sa is referred to as a back surface Sb.

The processed wafer W is a semiconductor wafer such as a silicon wafer, and a device layer D including a plurality of devices is formed on the surface Wa. Further, an oxide film Fw, for example, a SiO ₂ film (TEOS film) is further formed on the device layer D. The peripheral edge of the processed wafer W is chamfered, and the cross section of the peripheral edge becomes thinner toward the tip thereof.

The support wafer S is a wafer that supports the processed wafer W, and is, for example, a silicon wafer. An oxide film Fs, for example, a SiO ₂ film (TEOS film) is formed on the surface Sa of the support wafer S. Further, the support wafer S functions as a protective material for protecting the device on the surface Wa of the processing wafer W. When a plurality of devices on the surface Sa of the support wafer S are formed, a device layer (not shown) is formed on the surface Sa in the same manner as the processing wafer W.

In FIG. 2, the device layer D and the oxide films Fw and Fs are not shown in order to avoid the complexity of the drawing. Similarly, in other drawings used in the following description, the illustration of the device layer D and the oxide films Fw and Fs may be omitted.

As shown in FIG. 1, the wafer processing system 1 has a configuration in which the loading / unloading station 2 and the processing station 3 are integrally connected. At the loading / unloading station 2, for example, a cassette Ct capable of accommodating a plurality of polymerized wafers T is loaded / unloaded from the outside. The processing station 3 is provided with various processing devices that perform desired processing on the polymerized wafer T.

The loading / unloading station 2 is provided with a cassette mounting table 10. In the illustrated example, a plurality of, for example, four cassette Cts can be freely mounted in a row on the cassette mounting table 10 in the X-axis direction. The number of cassettes Ct mounted on the cassette mounting table 10 is not limited to this embodiment and can be arbitrarily determined.

The loading / unloading station 2 is provided with a wafer transport region 20 adjacent to the cassette mounting table 10. The wafer transfer region 20 is provided with a wafer transfer device 22 that is movable on a transfer path 21 extending in the X-axis direction. The wafer transfer device 22 has, for example, two transfer arms 23, 23 that hold and transfer the polymerized wafer T. Each transport arm 23 is configured to be movable in the horizontal direction, the vertical direction, the horizontal axis, and the vertical axis. The configuration of the transport arm 23 is not limited to this embodiment, and any configuration can be adopted.

The processing station 3 is provided with a wafer transfer region 30. The wafer transfer region 30 is provided with a wafer transfer device 32 that is movable on a transfer path 31 extending in the X-axis direction. The wafer transfer device 32 is configured to be able to transfer the polymerized wafer T to the transition device 34, the reforming device 40, the peripheral edge removing device 41, the separation device 42, the wet etching device 43, and the grinding device 44, which will be described later. Further, the wafer transfer device 32 has, for example, two transfer arms 33, 33 that hold and transfer the polymerized wafer T. Each transport arm 33 is configured to be movable in the horizontal direction, the vertical direction, the horizontal axis, and the vertical axis. The configuration of the transport arm 33 is not limited to this embodiment, and any configuration can be adopted.

A transition device 34 for delivering the polymerized wafer T is provided between the wafer transfer region 20 and the wafer transfer region 30.

The reformer 40 and the peripheral edge removing device 41 are arranged side by side in the X-axis direction from the loading / unloading station 2 side on the Y-axis positive direction side of the wafer transfer region 30. On the Y-axis negative direction side of the wafer transfer region 30, the separation device 42 and the wet etching device 43 are arranged in this order in the X-axis direction from the carry-in / out station 2 side. A grinding device 44 is arranged on the X-axis positive direction side of the wafer transfer region 30.

The reformer 40 irradiates the inside of the processed wafer W with laser light to form an internal surface reforming layer, a peripheral surface reforming layer, and a split reforming layer, which will be described later. As shown in FIG. 4, the reformer 40 has a chuck 50 that holds the polymerization wafer T in a state where the processing wafer W is on the upper side and the support wafer S is arranged on the lower side. The chuck 50 is configured to be movable in the X-axis direction and the Y-axis direction by the moving portion 51. The moving unit 51 is composed of a general precision XY stage. Further, the chuck 50 is configured to be rotatable around a vertical axis by a rotating portion 52.

Above the chuck 50, a first laser head 60 for forming an internal surface modification layer is provided as a laser irradiation unit that irradiates the inside of the processed wafer W with a laser beam. The first laser head 60 is a high-frequency pulsed laser beam oscillated from a laser beam oscillator (not shown), and is a laser beam having a wavelength that is transparent to the processing wafer W. Concentrate and irradiate the desired position inside the. As a result, the portion where the laser light is focused is modified inside the processed wafer W, and an internal surface modification layer is formed. Further, the first laser head 60 divides the laser light from the laser light oscillator into a plurality of pieces by, for example, a lens, and simultaneously irradiates the laser light. In such a case, a plurality of laser beams are irradiated from the first laser head 60, and a plurality of internal surface modification layers are simultaneously formed inside the processing wafer W. The first laser head 60 is configured to be movable in the X-axis direction and the Y-axis direction by the moving portion 61. The moving unit 61 is composed of a general precision XY stage. Further, the first laser head 60 is configured to be movable in the Z-axis direction by the elevating portion 62.

Further, above the chuck 50, a second laser head 70 as a peripheral modification laser head is provided as a laser irradiation unit that irradiates the inside of the processed wafer W with a laser beam. The second laser head 70 is a high-frequency pulsed laser beam oscillated from a laser beam oscillator (not shown), and emits a laser beam having a wavelength that is transparent to the processing wafer W. Concentrate and irradiate the desired position inside the. As a result, the portion where the laser light is focused is modified inside the processed wafer W to form a peripheral modification layer or a division modification layer. The second laser head 70 may irradiate a single focus laser beam or may irradiate a plurality of focal point laser beams. The second laser head 70 is configured to be movable in the X-axis direction and the Y-axis direction by the moving portion 71. The moving unit 71 is composed of a general precision XY stage. Further, the second laser head 70 is configured to be movable in the Z-axis direction by the elevating portion 72.

In the present embodiment, the moving unit 51, the rotating unit 52, and the moving unit 61 constitute the moving mechanism in the present disclosure. In the following description, when the first laser head 60 is moved in the horizontal direction, the first laser head 60 may be moved in the horizontal direction relative to the processing wafer W. That is, the processed wafer W may be moved in the horizontal direction. Further, when rotating the processed wafer W, the first laser head 60 may be rotated relative to the processed wafer W about the center of the processed wafer W. That is, the first laser head 60 may be rotated with respect to the processing wafer W.

The peripheral edge removing device 41 shown in FIG. 1 removes the peripheral edge portion of the processed wafer W from the peripheral edge reforming layer formed by the reforming device 40 as a base point.

The separating device 42 separates the back surface Wb side of the processed wafer W from the internal surface reforming layer formed by the reforming device 40 as a base point. As shown in FIG. 5, the separation device 42 has a mounting table 80 for holding the polymerization wafer T in a state where the processing wafer W is on the upper side and the support wafer S is arranged on the lower side. A refrigerant flow path 81 is formed inside the mounting table 80 as a cooling mechanism. A refrigerant such as cooling water or cooling gas is supplied to the refrigerant flow path 81 from a chiller unit (not shown) provided outside the reformer 40. Then, the support wafer S side (the surface Wa side of the processing wafer W) of the polymerization wafer T placed on the mounting table 80 is cooled by the refrigerant flowing through the refrigerant flow path 81. The cooling mechanism provided inside the mounting table 80 is not limited to this embodiment, and may be, for example, a Perche element or the like.

A third laser head 90 is provided above the mounting table 80 as a heating mechanism for irradiating the inside of the processing wafer W with laser light. The third laser head 90 is a high-frequency pulsed laser beam oscillated from a laser beam oscillator (not shown), and is a reforming device that reforms the laser beam having a wavelength that is transparent to the processing wafer W. The internal surface modification layer formed in 40 is irradiated. Then, the internal surface modification layer is heated. The laser beam may be continuously oscillated from the third laser head 90. The third laser head 90 may be configured to be movable in the X-axis direction and the Y-axis direction by the moving unit 91. The moving unit 91 is composed of a general precision XY stage. Further, the third laser head 90 may be configured to be movable in the Z-axis direction by the elevating portion 92.

Further, above the mounting table 80, a suction pad 100 that sucks and holds the back surface Wb of the processing wafer W is provided. The suction pad 100 is configured to be rotatable around a vertical axis by a rotating portion 101. Further, the suction pad 100 is configured to be movable in the Z-axis direction by the elevating portion 102.

The wet etching apparatus 43 shown in FIG. 1 supplies a chemical solution (etching solution) to the back surface Wb of the processing wafer W. Then, the back surface Wb ground by the grinding device 44 is etched. Grinding marks may be formed on the back surface Wb, and the back surface Wb constitutes a damaged surface. Further, as the chemical solution, for example, HF, HNO ₃ , H ₃ PO ₄ , TMAH, Choline, KOH and the like are used.

The grinding device 44 grinds the back surface Wb of the processed wafer W. Then, on the back surface Wb on which the internal surface modification layer is formed, the internal surface modification layer is removed, and further, the peripheral surface modification layer is removed. Specifically, the grinding device 44 is performed by rotating the processing wafer W (polymerized wafer T) and the grinding wheel in a state where the grinding wheel is in contact with the back surface Wb, and further lowering the grinding wheel. The internal surface modification layer and the peripheral surface modification layer described above are damaged layers, and the back surface Wb constitutes a damaged surface.

The wafer processing system 1 described above is provided with a control device 110. The control device 110 is, for example, a computer and has a program storage unit (not shown). The program storage unit stores a program that controls the processing of the polymerized wafer T in the wafer processing system 1. Further, the program storage unit also stores a program for controlling the operation of the drive system of the above-mentioned various processing devices and transfer devices to realize the wafer processing described later in the wafer processing system 1. The program may be recorded on a computer-readable storage medium H and may be installed on the control device 110 from the storage medium H.

Next, the wafer processing performed by using the wafer processing system 1 configured as described above will be described. FIG. 6 is a flow chart showing a main process of wafer processing. In the present embodiment, the processed wafer W and the supporting wafer S are bonded by a van der Waals force and a hydrogen bond (intermolecular force) in an external bonding device (not shown) of the wafer processing system 1, and the wafer is preliminarily polymerized. T is formed.

First, as shown in FIG. 7A, a cassette Ct containing a plurality of polymerized wafers T is placed on the cassette mounting table 10 of the loading / unloading station 2.

Next, the wafer transfer device 22 takes out the polymerized wafer T in the cassette Ct and transfers it to the transition device 34. Subsequently, the wafer transfer device 32 takes out the polymerized wafer T of the transition device 34 and transfers it to the reformer 40. In the reformer 40, as shown in FIG. 7B, the peripheral reforming layer M1 is formed inside the processed wafer W (step A1 in FIG. 6), and the split reforming layer M2 is formed (FIG. 6). Step A2).

In the reformer 40, the polymerized wafer T is delivered to and held by the chuck 50. After that, as shown in FIG. 8, the second laser head 70 is moved above the processing wafer W to the boundary between the peripheral portion We and the central portion Wc of the processing wafer W. After that, while rotating the chuck 50 by the rotating portion 52, the laser beam L is irradiated from the second laser head 70 to the inside of the processed wafer W to form the peripheral modification layer M1 inside the processed wafer W (FIG. Step A1 of step 6).

The peripheral edge modification layer M1 serves as a base point for removing the peripheral edge portion We in the edge trim, and as shown in FIGS. 8 and 9, the peripheral edge portion We and the central portion Wc to be removed in the processed wafer W It is formed in a ring along the boundary. The peripheral edge portion We is, for example, in the range of 1 mm to 5 mm in the radial direction from the outer end portion of the processed wafer W, and includes a chamfered portion.

Further, the peripheral modification layer M1 is stretched in the thickness direction and has a vertically long aspect ratio. The lower end of the peripheral modification layer M1 is located above the target surface (dotted line in FIG. 8) of the processed wafer W after grinding. That is, the distance H1 between the lower end of the peripheral modification layer M1 and the surface Wa of the processed wafer W is larger than the target thickness H2 of the processed wafer W after grinding. In such a case, the peripheral modification layer M1 does not remain on the processed wafer W after grinding.

Further, inside the processed wafer W, cracks C1 propagate from the peripheral modification layer M1 and reach the front surface Wa and the back surface Wb. A plurality of peripheral modification layers M1 may be formed in the thickness direction.

Next, in the same reforming apparatus 40, the second laser head 70 is moved, and as shown in FIG. 8, the split reforming layer M2 is inside the processing wafer W and outside in the radial direction of the peripheral reforming layer M1. (Step A2 in FIG. 6). The split modified layer M2 is also stretched in the thickness direction like the peripheral modified layer M1 and has a vertically long aspect ratio. Further, the crack C2 propagates from the split modified layer M2 and reaches the front surface Wa and the back surface Wb. A plurality of divided modified layers M2 may also be formed in the thickness direction.

Then, by forming a plurality of the split-modified layers M2 and the cracks C2 at a pitch of several μm in the radial direction, as shown in FIG. 9, the split-modified layer M1 extends radially outward from the peripheral modified layer M1. Layer M2 is formed. In the illustrated example, the divided and modified layers M2 of the line extending in the radial direction are formed at eight positions, but the number of the divided and modified layers M2 is arbitrary. At least, if the split reforming layer M2 is formed at two positions, the peripheral portion We can be removed. In such a case, when the peripheral edge portion We is removed in the edge trim, the peripheral edge portion We is divided into a plurality of parts by the divided modified layer M2 while being separated from the annular peripheral edge modified layer M1 as a base point. Then, the peripheral portion We to be removed is fragmented and can be removed more easily.

Next, the polymerized wafer T is transferred to the peripheral edge removing device 41 by the wafer transfer device 32. As shown in FIG. 7C, the peripheral edge removing device 41 removes the peripheral edge portion We of the processed wafer W from the peripheral edge modifying layer M1 as a base point (step A3 in FIG. 6).

In the peripheral edge removing device 41, for example, as shown in FIG. 10, the peripheral edge portion We is removed by expanding the tape 120. First, as shown in FIG. 10A, the expandable tape 120 is attached to the back surface Wb of the processing wafer W. Subsequently, as shown in FIG. 10B, the tape 120 is expanded in the radial direction of the processed wafer W, and the peripheral edge portion We is separated from the processed wafer W with the peripheral edge modifying layer M1 as a base point. At this time, the peripheral portion We is separated into small pieces with the split reforming layer M2 as a base point. Then, as shown in FIG. 10 (c), the tape 120 is raised and peeled from the processed wafer W to remove the peripheral edge We. At this time, in order to facilitate the peeling of the tape 120, a treatment for reducing the adhesive strength of the tape 120, for example, an ultraviolet irradiation treatment may be performed.

The method of removing the peripheral portion We is not limited to this embodiment. For example, an air blow or a water jet may be injected onto the peripheral edge portion We, and the peripheral edge portion We may be pressed and removed. Alternatively, a jig such as tweezers may be brought into contact with the peripheral edge portion We to physically remove the peripheral edge portion We.

Next, the polymerized wafer T is transferred to the reformer 40 again by the wafer transfer device 32. In the reformer 40, as shown in FIG. 7D, the internal surface reforming layer M3 is formed inside the processed wafer W (step A4 in FIG. 6).

As shown in FIG. 11, the laser beam L is irradiated from the first laser head 60 to the inside of the processed wafer W to form the internal surface modification layer M3. The internal surface modification layer M3 extends in the surface direction and has a horizontally long aspect ratio. The lower end of the internal surface modification layer M3 is located slightly above the target surface (dotted line in FIG. 11) of the processed wafer W after grinding. That is, the distance H3 between the lower end of the internal surface modification layer M3 and the surface Wa of the processed wafer W is slightly larger than the target thickness H2 of the processed wafer W after grinding. The internal surface modification layer M3 has a vertically long aspect ratio, and the plurality of internal surface modification layers M3 may be arranged with a small pitch. Further, cracks C3 grow in the plane direction from the internal surface modification layer M3. Further, when the pitch of the internal surface modification layer M3 is small, the crack C3 may not be present.

As shown in FIGS. 11 and 12, a plurality of, for example, nine laser beams L are simultaneously irradiated from the first laser head 60, and nine internal surface modification layers M3 are simultaneously formed as shown in FIG. 12 (a). Will be done. Then, the first laser head 60 and the polymerization wafer T are relatively moved in the horizontal direction to form the inner surface modification layer M3 in units of nine inside the central portion Wc of the processing wafer W. Specifically, first, as shown in FIG. 12B, the first laser head 60 is moved in the X-axis direction to form nine internal surface modification layers M3 arranged in a row. After that, as shown in FIG. 12 (c), the first laser head 60 is shifted in the Y-axis direction, and the first laser head 60 is further moved in the X-axis direction to form the nine internal surface modification layers M3. Form by arranging them in a separate row. These plurality of internal surface modification layers M3 are formed at the same height. Then, the internal surface modification layer M3 is formed on the entire internal surface in the central portion Wc. The number and arrangement of the laser beams L simultaneously emitted from the first laser head 60 are not limited to this embodiment, and can be arbitrarily set.

In the reformer 40, the first laser head 60 may be moved in the horizontal direction while rotating the chuck 50. In such a case, the internal surface modification layer M3 is formed in a spiral shape in a plan view. Then, the pitches of the plurality of internal surface reforming layers M3 may be changed in the concentric circular direction and the radial direction of the processed wafer W.

Next, the polymerized wafer T is transferred to the separation device 42 by the wafer transfer device 32. In the separation device 42, as shown in FIG. 7E, the back surface Wb side of the processed wafer W (hereinafter referred to as the back surface wafer Wb1) is separated from the internal surface modification layer M3 as a base point (step A5 in FIG. 6).

In the separation device 42, the polymerized wafer T is delivered to and placed on the mounting table 80 as shown in FIG. 13 (a). At this time, the support wafer S side (the surface Wa side of the processing wafer W) of the polymerization wafer T is cooled by the refrigerant flowing through the refrigerant flow path 81. After that, the third laser head 90 is moved above the processing wafer W, and the internal surface modification layer M3 is irradiated with the laser beam L from the third laser head 90. Further, the third laser head 90 is moved from the peripheral portion to the central portion of the processed wafer W, that is, moved in the wafer surface, and the entire surface of the internal surface modification layer M3 is irradiated with the laser beam L. Then, the internal surface modification layer M3 is heated. When the internal surface modification layer M3 is heated in this way, a stress difference is generated between the back surface Wb side and the front surface Wa side of the processed wafer W. Moreover, since the surface Wa side of the processed wafer W is cooled, this stress difference becomes large. Then, the back surface wafer Wb1 can be easily separated from the inner surface modified layer M3 as a base point.

After that, as shown in FIG. 13B, the back surface Wb of the processed wafer W is sucked and held by the suction pad 100. Then, the suction pad 100 is rotated to cut off the back surface wafer Wb1 with the internal surface modification layer M3 as a boundary. Then, as shown in FIG. 13 (c), the suction pad 100 is raised to separate the back surface wafer Wb1 from the processed wafer W in a state where the suction pad 100 sucks and holds the back surface wafer Wb1. If the back surface wafer Wb1 can be separated only by raising the suction pad 100 as shown in FIG. 13 (c), the rotation of the suction pad 100 shown in FIG. 13 (b) may be omitted.

Next, the polymerized wafer T is transferred to the grinding device 44 by the wafer transfer device 32. The grinding device 44 grinds the back surface Wb (damaged surface) of the processed wafer W as shown in FIG. 7 (f), and removes the internal surface modifying layer M3 and the peripheral surface modifying layer M1 remaining on the back surface Wb (FIG. Step A6) of 6. Specifically, the back surface Wb is ground by rotating the processing wafer W and the grinding wheel, respectively, and further lowering the grinding wheel in a state where the grinding wheel is in contact with the back surface Wb. The back surface Wb may be washed after grinding the back surface Wb in step A6 and before the wet etching in step A7 described later. For the cleaning treatment of the back surface Wb, for example, a brush may be used, or a pressurized cleaning liquid may be used.

Next, the polymerized wafer T is transferred to the wet etching device 43 by the wafer transfer device 32. In the wet etching apparatus 43, a chemical solution is supplied to the back surface Wb (damaged surface) of the processed wafer W to perform wet etching (step A7 in FIG. 6). Grinding marks may be formed on the back surface Wb ground by the above-mentioned grinding device 44. In this step A7, grinding marks can be removed by wet etching, and the back surface Wb can be smoothed.

After that, the polymerized wafer T that has been subjected to all the processing is transported to the transition device 34 by the wafer transfer device 32, and further transferred to the cassette Ct of the cassette mounting table 10 by the wafer transfer device 22. In this way, a series of wafer processing in the wafer processing system 1 is completed.

According to the above embodiment, after the inner surface modification layer M3 is formed inside the processed wafer W in step A4, the back surface wafer Wb1 is separated from the inner surface modification layer M3 in step A5. For example, as disclosed in Patent Document 1 described above, when the back surface Wb of the processed wafer W is ground, the grinding wheel wears and grinding water is used, so that waste liquid treatment is also required. On the other hand, in the present embodiment, the first laser head 60 itself does not deteriorate with time, and the number of consumables is reduced, so that the maintenance frequency can be reduced. Moreover, since it is a dry process using a laser, grinding water and wastewater treatment are not required. Therefore, the running cost can be reduced. Further, since the grinding water does not wrap around to the support wafer S side, it is possible to prevent the support wafer S from being contaminated.

In the present embodiment, the back surface Wb (damaged surface) is ground in step A6. In this grinding, the internal surface modified layer M3 and the peripheral surface modified layer M1 may be removed, and the grinding amount is several. It is as small as about 10 μm. On the other hand, when the back surface Wb is ground to thin the processed wafer W as in the conventional case, the grinding amount is as large as 700 μm or more, and the degree of wear of the grinding wheel is large. Therefore, in the present embodiment, the maintenance frequency can also be reduced.

Further, according to the present embodiment, in step A4, a plurality of laser beams L are simultaneously irradiated to the inside of the processed wafer W to form a plurality of internal surface modification layers M3 at the same time. Therefore, the internal surface modification layer M3 can be efficiently formed on the entire internal surface of the processed wafer W, and the time required for the processing in step A4 can be shortened. As a result, the throughput of wafer processing can be improved.

Further, according to the present embodiment, in step A5, the internal surface modified layer M3 is heated by irradiating the internal surface modified layer M3 with laser light L from the third laser head 90. Therefore, a stress difference is generated between the back surface Wb side and the front surface Wa side of the processed wafer W. Moreover, since the surface Wa side of the processed wafer W is cooled, this stress difference becomes large. As a result, the back surface wafer Wb1 can be easily separated from the inner surface modified layer M3 as a base point. In the present embodiment, since the third laser head 90 is moved from the peripheral portion to the central portion of the processed wafer W, the stress acting on the internal surface modification layer M3 acts from the peripheral portion to the central portion. do. Therefore, it is easier to separate the back surface wafer Wb1.

Further, according to the present embodiment, in performing edge trimming, after forming the peripheral edge modifying layer M1 inside the processed wafer W in step A1, the peripheral edge portion We is removed from the peripheral edge modifying layer M1 in step A3. doing. For example, in the method disclosed in Patent Document 1 described above, the peripheral portion We is ground or cut, and the grinding wheel wears and requires regular replacement. On the other hand, in the present embodiment, the degree of deterioration of the first laser head 60 itself with time is small, and the maintenance frequency can be reduced.

However, this disclosure does not exclude edge trim by grinding.

Further, according to the present embodiment, since the split reforming layer M2 is formed in step A2, the peripheral edge portion We removed in step A3 can be fragmented. Therefore, edge trimming can be performed more easily.

Moreover, the formation of the peripheral modification layer M1 in step A1, the formation of the split modification layer M2 in step A2, and the formation of the internal surface modification layer M3 in step A4 can be performed in the same modification device 40. Therefore, the equipment cost can be reduced. Of course, the peripheral modification layer M1, the division modification layer M2, and the inner surface modification layer M3 may be formed by separate devices. For example, when the above-mentioned wafer processing is continuously performed on a plurality of polymerized wafers T, the peripheral modified layer M1, the divided modified layer M2, and the internal surface modified layer M3 are formed by separate devices. , The throughput of wafer processing can be improved.

Further, according to the present embodiment, the back surface Wb (damaged surface) is ground in step A6 to remove the internal surface modified layer M3 and the peripheral surface modified layer M1, so that the yield of the processed wafer W, which is a product, is improved. be able to.

In this embodiment, the processing order of steps A1 to A7 can be changed.
As a modification 1, the order of removing the peripheral portion We of step A3 and forming the internal surface modification layer M3 of step A4 may be changed. In such a case, the wafer processing is performed in the order of steps A1 to A2, A4, A3, and A5 to A7.
As a modification 2, the formation of the internal surface modification layer M3 in step A4 may be performed before the formation of the peripheral modification layer M1 in step A1. In such a case, the wafer processing is performed in the order of steps A4, A1 to A3, and A5 to A7.

Next, another embodiment in which the internal surface modification layer M3 is formed inside the processed wafer W will be described.

As shown in FIG. 14, the reformer 200 according to another embodiment is obtained by changing the configuration of the laser irradiation unit from the configuration of the reformer 40 shown in FIG. That is, the reformer 200 has a fourth laser head 210 and a fifth laser head 220 as a laser irradiation unit instead of the first laser head 60. Then, in the reformer 40, a plurality of laser beams L were irradiated from the first laser head 60, and in the reformer 200, the laser beams L were emitted from each of the fourth laser head 210 and the fifth laser head 220. Irradiate. The other configurations of the reformer 200 are the same as the configurations of the reformer 40.

The fourth laser head 210 and the fifth laser head 220 are provided above the chuck 50, respectively. The fourth laser head 210 and the fifth laser head 220 are high-frequency pulsed laser beams L oscillated from a laser light oscillator (not shown), respectively, and have transparency to the processing wafer W. The laser beam L having a wavelength is focused and irradiated at a desired position inside the processing wafer W. As a result, the portion where the laser beam L is focused is modified inside the processed wafer W, and the internal surface modification layers M4 and M5 described later are formed.

The fourth laser head 210 is configured to be movable in the X-axis direction and the Y-axis direction by the moving portion 211. The moving unit 211 is composed of a general precision XY stage. Further, the fourth laser head 210 is configured to be movable in the Z-axis direction by the elevating portion 212. Similarly, the fifth laser head 220 is also configured to be movable in the X-axis direction and the Y-axis direction by the moving unit 221 and movable in the Z-axis direction by the elevating unit 222.

In the above reformer 200, as shown in FIG. 15, the fourth laser head 210 is arranged in the upper center portion of the processing wafer W, and the fifth laser head 220 is arranged in the upper peripheral portion of the processing wafer W. That is, the laser heads 210 and 220 are arranged at different positions in the radial direction of the processing wafer W. After that, as shown in FIGS. 15 and 16A, the inside of the processed wafer W is irradiated with the laser beam L from the fourth laser head 210 to form the internal surface modification layer M4. Further, the inside of the processed wafer W is irradiated with the laser beam L from the fifth laser head 220 to form the internal surface modification layer M5. Then, the laser heads 210 and 220 and the polymerization wafer T are relatively moved to form the internal surface modification layers M4 and M5 inside the central portion Wc of the processing wafer W.

Specifically, first, as shown in FIG. 16B, the processed wafer W (polymerized wafer T) is rotated 360 degrees while irradiating the inside of the processed wafer W with laser light from each of the laser heads 210 and 220. .. Then, the annular internal surface modification layers M4 and M5 are simultaneously formed inside the processed wafer W (rotation step). After that, as shown in FIG. 16B, the laser heads 210 and 220 are shifted in the X-axis direction (diameter direction) (movement step). In this second step, the directions of shifting the laser heads 210 and 220 may be from the outside to the inside or from the inside to the outside as shown in the illustrated example. Then, as shown in FIG. 16C, the polymerization wafer T is rotated 360 degrees while irradiating the inside of the processed wafer W with laser light from each of the laser heads 210 and 220. Then, another annular internal surface modification layers M4 and M5 are formed inside the processed wafer W, respectively. In this way, the formation of the annular inner surface modification layers M4 and M5 (rotation step) and the movement of the laser heads 210 and 220 in the X-axis direction (movement step) are repeated, and the entire inner surface at the central portion Wc is formed. Internal surface modification layers M4 and M5 are formed on the surface.

In the example of FIG. 16, the formation of the annular internal surface modification layers M4 and M5 (rotation step) and the movement of the laser heads 210 and 220 in the X-axis direction (movement step) were performed individually. , These may be performed at the same time. That is, as shown in FIG. 17, laser light is irradiated to the inside of the processing wafer W from each of the laser heads 210 and 220. At this time, the laser heads 210 and 220 are moved in the radial direction while rotating the processing wafer W. Then, the inner surface modification layers M4 and M5 are formed in a spiral shape, respectively.

As described above, in both the case of forming the annular inner surface modified layers M4 and M5 and the case of forming the spiral inner surface modified layers M4 and M5, the same effect as that of the above embodiment can be obtained. You can enjoy it. That is, the internal surface modification layers M4 and M5 can be efficiently formed on the entire internal surface of the processed wafer W, and the throughput of wafer processing can be improved.

Moreover, according to the present embodiment, since the two laser heads 210 and 220 are used, the movement of the laser heads 210 and 220 in the radial direction is reduced. For example, when moving one laser head in the radial direction, it is necessary to move it by the diameter of the processing wafer W. In contrast, in the present embodiment, the radial movement of the laser heads 210 and 220 is, for example, processing. It is about 1/4 of the diameter of the wafer W. As a result, the occupied area of the reformer 200 can be reduced, and the reformer 200 can be miniaturized.

Further, according to the present embodiment, since the internal surface modification layers M4 and M5 are formed in a ring shape or a spiral shape in step A4, the stress applied in the circumferential direction is applied when the back surface wafer Wb1 is separated in the subsequent step A5. It becomes even and the separation can be made easier.

In the present embodiment, the fourth laser head 210 and the fifth laser head 220 are arranged at different positions in the radial direction, and the rotation speeds of the processed wafer W are different at the positions. Therefore, when the interval between the inner surface modification layer M4 and the interval between the inner surface modification layer M5 are the same, the frequency of the laser light L emitted from the fourth laser head 210 and the fifth laser head 220 is set. adjust. Specifically, when the frequency of the laser beam L from the fourth laser head 210 is reduced and the frequency of the laser beam L from the fifth laser head 220 is increased, the spacing between the internal surface modification layers M4 and the internal surface are increased. The interval between the modified layers M5 can be the same. By making the intervals the same in this way, the internal surface modification layers M4 and M5 can be uniformly formed on the wafer surface, and then the back surface wafer Wb1 can be easily separated.

In the reformer 200, the internal surface reforming layer can be formed by yet another method. For example, as shown in FIG. 18, the processed wafer W is divided into two areas W1 and W2. A fourth laser head 210 is arranged in the area W1, and a fifth laser head 220 is arranged in the area W2. In the area W1, the fourth laser head 210 is moved in the X-axis direction to form a row of internal surface modification layers M6. After that, the fourth laser head 210 is shifted in the Y-axis direction, and the fourth laser head 210 is further moved in the X-axis direction to form a separate row of internal surface modification layers M6. Then, the internal surface modification layer M6 is formed on the entire internal surface of the area W1. Similarly, in the area W2, the internal surface modification layer M7 is formed on the entire internal surface of the area W2 by using the fifth laser head 220. As described above, in the present embodiment, the internal surface modification layers M6 and M7 can be simultaneously formed in the areas W1 and W2, respectively. Therefore, the same effect as that of the above embodiment can be enjoyed.

The number of areas for partitioning the processed wafer W is not limited to the above embodiment. As shown in FIG. 19, the processed wafer W may be divided into three areas W1 to W3. In such a case, it is preferable that the reformer 200 is provided with one more laser head for forming the internal surface reforming layer in addition to the laser heads 210 and 220. By arranging one laser head in each of the areas W1 to W3, the internal surface modification layers M8, M9, and M10 can be simultaneously formed in each of the areas W1, W2, and W3. In other words, as the number of the processed wafers W partitioned increases, the time for forming the internal surface modification layer can be shortened, and the wafer processing throughput can be improved.

Further, as shown in FIG. 20, the processed wafer W may be divided into four areas W1 to W4. Each area W1 to W4 is partitioned by the center line of the processing wafer W, that is, is partitioned in a fan shape having the center of the processing wafer W as an apex. In such a case, for example, the fourth laser head 210 is arranged in the area W1 and the fifth laser head 220 is arranged in the area W3. Then, the internal surface modification layers M11 and M12 are simultaneously formed in the areas W1 and W3, respectively. After that, the processed wafer W is rotated 90 degrees. Then, the fourth laser head 210 is arranged in the area W2, and the fifth laser head 220 is arranged in the area W4. Then, an internal surface modification layer is simultaneously formed in each of the areas W1 and W3.

The number of areas for partitioning the processed wafer W in a fan shape as described above is not limited to the above embodiment. The processing wafer W may be rotated according to the number of areas and the number of laser heads.

Further, when the processed wafer W is divided into the fan-shaped areas W1 to W4 as shown in FIG. 20, the reformer 40 may be used. In such a case, the first laser head 60 can be sequentially moved to the areas W1 to W4 to form an internal surface modification layer in each of the areas W1 to W4.

In the above reforming apparatus 200, the laser heads 210 and 220 for forming the internal surface reforming layer and the second laser head 70 for forming the peripheral reforming layer and the split reforming layer were separately provided. However, it may be shared. For example, the fifth laser head 220 may be used to form the peripheral modified layer and the divided modified layer. Alternatively, for example, the second laser head 70 may be used to form the internal surface modification layer.

Next, another embodiment of the separation device 42 will be described.

As shown in FIG. 21, the separation device 300 according to another embodiment is obtained by changing the configuration of the heating mechanism from the configuration of the separation device 42 shown in FIG. That is, the separation device 300 has an infrared irradiation unit 310 instead of the third laser head 90 as a heating mechanism. The infrared irradiation unit 310 is provided above the mounting table 80. The infrared irradiation unit 310 irradiates the entire surface of the inner surface modification layer M3 with infrared rays R to heat the inner surface modification layer M3. The other configurations of the separation device 300 are the same as the configurations of the separation device 42.

In this embodiment as well, the same effects as those in the above embodiment can be enjoyed. That is, by heating the inner surface modification layer M3, a stress difference can be generated between the back surface Wb side and the front surface Wa side of the processed wafer W, and the back surface wafer Wb1 can be easily separated. The infrared irradiation unit 310 may be moved in the horizontal direction by a moving mechanism (not shown) to irradiate the entire surface of the internal surface modification layer M3 with infrared rays R.

As shown in FIG. 22, the separation device 320 according to the other embodiment is obtained by changing the configuration of the cooling mechanism from the configuration of the separation device 42 shown in FIG. That is, the separation device 320 has a wafer holding unit 330 and an air supply unit 331 instead of the mounting table 80. The wafer holding portion 330 holds the outer peripheral portion of the polymerization wafer T (supporting wafer S). The air supply unit 331 supplies air to the polymerized wafer T held by the wafer holding unit 330, and cools the support wafer S side (the surface Wa side of the processed wafer W) of the polymerized wafer T. The other configurations of the separating device 320 are the same as the configurations of the separating device 42.

In this embodiment as well, the same effects as those in the above embodiment can be enjoyed. That is, by cooling the front surface Wa side of the processed wafer W, the stress difference generated between the back surface Wb side and the front surface Wa side of the processed wafer W can be increased.

Next, the wafer processing according to another embodiment performed by using the wafer processing system 1 will be described. FIG. 23 is a flow chart showing a main process of wafer processing. In this embodiment, detailed description of the same processing as that of the embodiment shown in FIG. 6 will be omitted.

First, as shown in FIG. 24A, a cassette Ct containing a plurality of polymerized wafers T is placed on the cassette mounting table 10 of the loading / unloading station 2.

Next, the wafer transfer device 22 takes out the polymerized wafer T in the cassette Ct and transfers it to the transition device 34. Subsequently, the wafer transfer device 32 takes out the polymerized wafer T of the transition device 34 and transfers it to the reformer 40. In the reforming apparatus 40, the peripheral reforming layer M13 is formed inside the processed wafer W as shown in FIG. 24 (b) (step B1 in FIG. 23).

In the reformer 40, as shown in FIG. 25, the second laser head 70 is moved above the processing wafer W to the boundary between the peripheral portion We and the central portion Wc of the processing wafer W. After that, the laser beam L is irradiated from the second laser head 70 to the inside of the processing wafer W while rotating the chuck 50 by the rotating portion 52. Then, an annular peripheral modification layer M13 is formed along the boundary between the peripheral portion We and the central portion Wc.

Similar to the peripheral modification layer M1 of the above embodiment, the peripheral modification layer M13 is stretched in the thickness direction, and the lower end of the peripheral modification layer M13 is the target surface of the processed wafer W after grinding (dotted line in FIG. 25). ) Is located above. Further, the peripheral modification layer M13 is formed at the same height as the internal surface modification layer M14, which will be described later.

However, in the peripheral modification layer M1 shown in FIG. 7, the crack C1 extends to the front surface Wa and the back surface Wb, whereas the crack C13 from the peripheral modification layer M13 extends only to the front surface Wa and reaches the back surface Wb. Does not reach.

Next, in the reforming apparatus 40, the internal surface reforming layer M14 is formed inside the processed wafer W as shown in FIG. 24 (c) (step B2 in FIG. 23). Similar to the internal surface modification layer M3 shown in FIG. 7, the internal surface modification layer M14 extends in the plane direction of the processed wafer W. Further, the internal surface modification layer M14 is formed at the same height as the peripheral surface modification layer M13, and the lower end of the internal surface modification layer M14 is located above the target surface of the processed wafer W after grinding. A plurality of internal surface modification layers M14 are formed in the surface direction, and the plurality of internal surface modification layers M14 are formed in the surface direction from the central portion to the peripheral modification layer M13, that is, in the central portion Wc. The method for forming the inner surface modified layer M14 is the same as the method for forming the inner surface modified layer M3 in step A4. Further, cracks C14 grow in the plane direction from the internal surface modification layer M14. Further, when the pitch of the internal surface modification layer M14 is small, the crack C14 may not be present.

Next, the polymerized wafer T is transferred to the separation device 42 by the wafer transfer device 32. In the separation device 42, as shown in FIG. 24D, the back surface Wb side (hereinafter referred to as the back surface wafer Wb2) of the processed wafer W is separated from the inner surface modification layer M14 and the peripheral surface modification layer M13 as base points (FIG. FIG. Step B3 of 23). At this time, since the inner surface modification layer M14 and the peripheral modification layer M13 are formed at the same height, the back surface wafer Wb2 is integrally separated from the peripheral edge portion We. The method for separating the back surface wafer Wb2 is the same as the method for separating the back surface wafer Wb1 in step A5.

Next, the polymerized wafer T is transferred to the grinding device 44 by the wafer transfer device 32. The grinding device 44 grinds the back surface Wb (damaged surface) of the processed wafer W as shown in FIG. 24 (e), and removes the internal surface modifying layer M14 and the peripheral surface modifying layer M13 remaining on the back surface Wb (FIG. Step B4 of 23). The method of grinding the back surface Wb is the same as the method of grinding the back surface Wb in step A6.

Next, the polymerized wafer T is transferred to the wet etching device 43 by the wafer transfer device 32. In the wet etching apparatus 43, a chemical solution is supplied to the back surface Wb (damaged surface) of the processed wafer W to perform wet etching (step B5 in FIG. 23). The method of wet etching the back surface Wb is the same as the method of wet etching the back surface Wb in step A7.

After that, the polymerized wafer T that has been subjected to all the processing is transported to the transition device 34 by the wafer transfer device 32, and further transferred to the cassette Ct of the cassette mounting table 10 by the wafer transfer device 22. In this way, a series of wafer processing in the wafer processing system 1 is completed.

In the above embodiments, the same effects as those in the above embodiments can be enjoyed. Moreover, in the present embodiment, since the diameter of the back surface wafer Wb2 is the same as the diameter of the processed wafer W before processing, the back surface wafer Wb2 can be reused. Then, the wafer processing system 1 may be provided with a recovery unit for collecting the separated back surface wafer Wb2 and a cleaning unit for cleaning the back surface wafer Wb2. Further, in addition to collecting and cleaning the back surface wafer Wb2, the back surface wafer Wb2 may be ground, and in such a case, the wafer processing system 1 may be provided with a grinding portion. Further, the back surface wafer Wb2 may be wet-etched, and in such a case, the wafer processing system 1 may be provided with a wet-etched portion.

In this embodiment, the processing order of steps B1 to B5 can be changed. As a modification, the order of forming the peripheral modification layer M13 in step B1 and the formation of the internal surface modification layer M14 in step B2 may be changed. In such a case, the wafer processing is performed in the order of steps B2, B1, B3 to B5.

Next, the wafer processing according to another embodiment performed by using the wafer processing system 1 will be described. This embodiment is almost the same as the embodiment shown in FIG. 24, but the internal surface modification layer formed in step B2 is different.

In step B2, the internal surface modification layer M15 is formed inside the processed wafer W as shown in FIG. 26 (c). While the internal surface modification layer M14 shown in FIG. 24 was formed up to the peripheral surface modification layer M13, the internal surface modification layer M15 of the present embodiment extends from the central portion to the outer end portion in the plane direction. It is formed. The crack C15 grows in the plane direction from the internal surface modification layer M15. Further, when the pitch of the internal surface modification layer M15 is small, the crack C15 may not be present.

In such a case, in step B3, as shown in FIG. 26D, the back surface wafer Wb2 above the internal surface modification layer M15 and the peripheral edge portion We below the internal surface modification layer M15 are separately separated. .. That is, the back surface wafer Wb2 is separated from the inner surface modified layer M15 as a base point, and the peripheral edge portion We is separated from the peripheral surface modified layer M13 as a base point. The other steps B1 and B4 to B5 are the same as those of the embodiment shown in FIG. 24.

In the above embodiments, the same effects as those in the above embodiments can be enjoyed.

The wafer processing system 1 of the above embodiment may have a CMP apparatus (CMP: Chemical Mechanical Polishing, chemical mechanical polishing) instead of the wet etching apparatus 43. This CMP apparatus functions in the same manner as the wet etching apparatus 43. That is, in the CMP apparatus, the back surface Wb (damaged surface) ground by the grinding apparatus 44 is polished. Then, the grinding device 44 removes the grinding marks formed on the back surface Wb and smoothes the back surface Wb.

As described above, in the grinding apparatus 44, the back surface Wb was ground to remove the internal surface modifying layer and the peripheral surface modifying layer. In this regard, if the internal surface modification layer and the peripheral modification layer can be removed only by the wet etching apparatus 43 or the CMP apparatus, the grinding apparatus 44 may be omitted. Further, the treatment of the back surface Wb (damaged surface) may be performed only by the grinding apparatus 44, and in such a case, the wet etching apparatus 43 or the CMP apparatus may be omitted.

Further, in the wafer processing system 1, the processing wafer W and the support wafer S are bonded by an external bonding device of the wafer processing system 1, but such a bonding device may be provided inside the wafer processing system 1. .. In such a case, cassettes Cw, Cs, and Ct capable of accommodating a plurality of processing wafers W, a plurality of support wafers S, and a plurality of polymerization wafers T are carried in and out of the carry-in / out station 2. Then, these cassettes Cw, Cs, and Ct are freely mounted in a row in the X-axis direction on the cassette mounting table 10.

When joining the processed wafer W and the support wafer S, if the oxide films Fw and Fs are also joined at the peripheral edge portion We, pretreatment is performed on the oxide films Fw and Fs before the joining treatment. You may go. As the pretreatment, for example, the surface layers of the oxide films Fw and Fs on the peripheral portion We may be removed, or the oxide films Fw and Fs may be projected. Alternatively, the surface of the oxide film Fw may be roughened to roughen the surface. By performing such a pretreatment, it is possible to suppress the bonding of the oxide films Fw and Fs at the peripheral portion We, and it is possible to appropriately remove the peripheral portion We.

When the oxide film Fs is removed as the pretreatment described above, for example, the bonding surface Sj of the support wafer S at the portion corresponding to the peripheral edge portion We to be removed may be etched. Specifically, for example, the interface treatment device 400 shown in FIG. 27 is used. The interface treatment device 400 is provided inside the wafer processing system 1 together with, for example, the above-mentioned joining device (not shown).

The interface treatment device 400 has a chuck 401 that holds the support wafer S in a state where the surface Sa faces upward. The chuck 401 is configured to be rotatable around a vertical axis by a rotation mechanism 402.

Above the chuck 401, a first nozzle 403 as a first liquid supply unit for supplying the first etching liquid E1 and a second etching liquid E2 are supplied to the surface Sa of the support wafer S. A second nozzle 404 is provided as a second liquid supply unit. The nozzles 403 and 404 communicate with an etching solution supply source (not shown) that stores and supplies the etching solutions E1 and E2, respectively. Further, the nozzles 403 and 404 may be configured to be movable in the X-axis direction, the Y-axis direction and the Z-axis direction by a moving mechanism (not shown), respectively.

The first etching solution E1 etches the oxide film Fs formed on the surface Sa of the support wafer S. For the first etching solution E1, for example, HF (hydrogen fluoride) or the like is used. The second etching solution E2 etches the surface Sa of the support wafer S, that is, silicon. For the second etching solution E2, for example, TMAH (tetramethylammonium hydroxide), Choline (choline), KOH (potassium hydroxide) and the like are used.

In such a case, the support wafer S conveyed to the interface treatment apparatus 400 has an oxide film Fs formed on its surface Sa as shown in FIG. 28 (a). Then, while rotating the chuck 401 as shown in FIG. 28B, the first etching solution E1 is supplied from the first nozzle 403 to the peripheral portion of the oxide film Fs, and the peripheral portion of the oxide film Fs is etched. Will be done. In the present embodiment, the end portion of the etched oxide film Fs coincides with the position where the peripheral modification layer M1 described later is formed, that is, the end portion of the peripheral edge portion We to be removed.

Next, while rotating the chuck 401 as shown in FIG. 28 (c), the second etching solution E2 is supplied from the second nozzle 404 to the peripheral edge of the surface Sa of the support wafer S, and the surface Sa (silicon) is supplied. The peripheral part of the part) is etched. At this time, since i such as TMAH, Choline, and KOH described above is used as the second etching solution E2, the oxide film Fs is not etched, and the surface Sa is etched using the oxide film Fs as a mask. Further, the surface Sa is etched by, for example, several μm in the thickness direction.

Next, the etching-treated support wafer S and the processed wafer W are each conveyed to a joining device (not shown). In the joining apparatus, as shown in FIG. 28D, the processed wafer W and the supporting wafer S are joined to form the polymerized wafer T. At this time, the processing wafer W and the support wafer S are not joined at the peripheral portion We.

Next, in the wafer processing system 1, for example, step A1 shown in FIG. 6 is performed, and as shown in FIG. 28D, a peripheral modification layer M1 is formed inside the processed wafer W. At this time, the position of the peripheral modification layer M1 and the position of the end portion of the oxide film Fs are the same.

After that, in the wafer processing system 1, for example, steps A2 and A3 shown in FIG. 6 are sequentially performed to form the split reforming layer M2, and then the peripheral edge We is removed from the peripheral modification layer M1 and the crack C as base points. Will be done. When the peripheral edge portion We is removed, the processed wafer W and the support wafer S are not joined, so that the peripheral edge portion We can be appropriately removed.

Here, for example, when the film thickness of the oxide film Fs is small, there is a possibility that the peripheral portion We may reattach after the processed wafer W and the support wafer S are joined by simply etching the oxide film Fs. In this respect, in the present embodiment, since the surface Sa of the support wafer S is etched in addition to the oxide film Fs, the re-adhesion can be suppressed, and the processed wafer W and the support wafer S can be suppressed at the peripheral edge portion We. The unjoined region can be maintained. For example, when the film thickness of the oxide film Fs is sufficiently large, the etching of the surface Sa may be omitted.

Further, in the present embodiment, an alkaline liquid is used as the second etching liquid E2. In such a case, when the surface Sa of the support wafer S is etched with the second etching solution E2, the surface Sa is roughened. Then, the joining and re-adhesion of the processed wafer W and the supporting wafer S at the peripheral portion We can be more reliably suppressed.

In the present embodiment, the position of the end portion of the etched oxide film Fs and the position of the peripheral modification layer M1 are matched as shown in FIG. 28 (d), but the peripheral edge is modified as shown in FIG. 29. The layer M1 may be formed radially inside the end of the oxide film Fs. In other words, the etching of the oxide film Fs may be performed on the radial outer side of the peripheral modification layer M1.

In such a case, when the peripheral modification layer M1 is formed, even if the peripheral modification layer M1 is formed so as to be displaced from the end portion of the oxide film Fs due to, for example, a processing error, the peripheral modification layer M1 is formed of the oxide film Fs. It can be suppressed from being formed radially outward from the end of the. Here, if the peripheral edge modification layer M1 is formed radially outward from the end portion of the oxide film Fs, the processed wafer W floats with respect to the support wafer S after the peripheral edge portion We is removed. .. In this respect, in the present embodiment, the state of the processed wafer W can be reliably suppressed.

As a result of diligent studies by the present disclosers, it has been confirmed that the peripheral edge We can be appropriately removed when the distance G between the end of the oxide film Fs and the peripheral modification layer M1 is sufficiently small. The distance G is preferably within 500 μm.

Further, in the example of FIG. 29, the peripheral modification layer M1 was formed radially inside the end of the oxide film Fs, but the formation position of the peripheral modification layer M1 is subjected to another treatment as a pretreatment for the bonding treatment. It can also be applied when doing. Examples of the pretreatment include removing the surface layers of the oxide films Fw and Fs on the peripheral portion We, projecting the oxide films Fw and Fs, and roughening the surface of the oxide film Fw to roughen the surface. In any case, the peripheral modification layer M1 may be formed radially inside the end of the interface between the processed wafer W and the support wafer S.

The method of removing the oxide films Fw and Fs as a pretreatment is not limited to the etching described above, and for example, the oxide films Fw and Fs may be polished. Specifically, for example, the interface treatment device 410 shown in FIG. 30 is used. The interface treatment device 410 is provided in place of the interface treatment device 400, for example, inside the wafer processing system 1.

The interface treatment device 410 has a chuck 411 that holds the processing wafer W in a state where the oxide film Fw faces upward. The chuck 411 is configured to be rotatable around a vertical axis by a rotation mechanism 412.

Above the chuck 411, a polishing member 413 is provided which is pressed against the peripheral edge of the oxide film Fw to remove the peripheral edge of the oxide film Fw. The polishing member 413 is configured to be movable in the Z-axis direction by a moving mechanism (not shown).

By removing the peripheral edge portion of the oxide film Fw using the polishing member 413 in this way, the processed wafer W and the support wafer S are not joined at the peripheral edge portion We, and the peripheral edge portion We is appropriately removed in the subsequent processing. be able to. Further, since the damaged layer is formed on the surface of the oxide film Fw, the re-adhesion between the processed wafer W and the supporting wafer S can be suppressed, and the unbonded region can be maintained.

Further, since the surface particle size of the polishing member 413, that is, the abrasive particle size of the polishing member 413 can be arbitrarily selected, the film removal rate of the oxide film Fw and the surface roughness of the oxide film Fw after film removal can be arbitrarily selected. Can be adjusted to. Thereby, the re-adhesion of the unbonded region can be suppressed more appropriately.

In the present embodiment, the oxide film Fw of the processed wafer W is polished, but the same treatment may be performed on the oxide film Fs of the support wafer S.

Further, in the present embodiment, the unbonded region is formed on the processed wafer W (or the support wafer S) before joining, but the unbonded region may be formed after joining. For example, by irradiating the outer peripheral portion of the oxide film Fw with a laser beam after bonding, it is possible to reduce the bonding strength and form an unbonded region.

In the wafer processing system 1 of the above embodiment, trimming may be performed according to the notch of the processed wafer W.

In the above embodiment, the case where the processed wafer W and the support wafer S are directly bonded has been described, but the processed wafer W and the support wafer S may be bonded via an adhesive.

Further, in the above-described embodiment, the case where the processed wafer W in the polymerized wafer T is thinned has been described, but the above-described embodiment can also be applied to the case where one wafer is thinned. Further, the above embodiment can also be applied when the polymerization wafer T is peeled off from the processing wafer W and the support wafer S. For example, the above embodiment can be applied even when the object to be processed is an ingot and a substrate is produced from the ingot.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The above embodiments may be omitted, replaced or modified in various forms without departing from the scope of the appended claims and their gist.

1 Wafer processing system 40 Reformer 42 Separator 51 Moving part 52 Rotating part 60 First laser head 61 Moving part S Supporting wafer T Polymerized wafer W Processing wafer

The loading / unloading station 2 is provided with a cassette mounting table 10. In the illustrated example, a plurality of, for example, four cassette Cts can be freely mounted in a row on the cassette mounting table 10 in the Y-axis direction. The number of cassettes Ct mounted on the cassette mounting table 10 is not limited to this embodiment and can be arbitrarily determined.

The loading / unloading station 2 is provided with a wafer transport region 20 adjacent to the cassette mounting table 10. The wafer transfer region 20 is provided with a wafer transfer device 22 that is movable on a transfer path 21 extending in the Y-axis direction. The wafer transfer device 22 has, for example, two transfer arms 23, 23 that hold and transfer the polymerized wafer T. Each transport arm 23 is configured to be movable in the horizontal direction, the vertical direction, the horizontal axis, and the vertical axis. The configuration of the transport arm 23 is not limited to this embodiment, and any configuration can be adopted.

Specifically, first, as shown in FIG. 16B, the processed wafer W (polymerized wafer T) is rotated 360 degrees while irradiating the inside of the processed wafer W with laser light from each of the laser heads 210 and 220. .. Then, the annular internal surface modification layers M4 and M5 are simultaneously formed inside the processed wafer W (rotation step). After that, as shown in FIG. 16B, the laser heads 210 and 220 are shifted in the X-axis direction (diameter direction) (movement step). In this moving step, the directions of shifting the laser heads 210 and 220 may be from the outside to the inside or from the inside to the outside as shown in the illustrated example. Then, as shown in FIG. 16C, the polymerization wafer T is rotated 360 degrees while irradiating the inside of the processed wafer W with laser light from each of the laser heads 210 and 220. Then, another annular internal surface modification layers M4 and M5 are formed inside the processed wafer W, respectively. In this way, the formation of the annular inner surface modification layers M4 and M5 (rotation step) and the movement of the laser heads 210 and 220 in the X-axis direction (movement step) are repeated, and the entire inner surface at the central portion Wc is formed. Internal surface modification layers M4 and M5 are formed on the surface.

Further, as shown in FIG. 20, the processed wafer W may be divided into four areas W1 to W4. Each area W1 to W4 is partitioned by the center line of the processing wafer W, that is, is partitioned in a fan shape having the center of the processing wafer W as an apex. In such a case, for example, the fourth laser head 210 is arranged in the area W1 and the fifth laser head 220 is arranged in the area W3. Then, the internal surface modification layers M11 and M12 are simultaneously formed in the areas W1 and W3, respectively. After that, the processed wafer W is rotated 90 degrees. Then, the fourth laser head 210 is arranged in the area W2, and the fifth laser head 220 is arranged in the area W4. Then, an internal surface modification layer is simultaneously formed in each of the areas W2 and W4.

Further, in the wafer processing system 1, the processing wafer W and the support wafer S are bonded by an external bonding device of the wafer processing system 1, but such a bonding device may be provided inside the wafer processing system 1. .. In such a case, cassettes Cw, Cs, and Ct capable of accommodating a plurality of processing wafers W, a plurality of support wafers S, and a plurality of polymerization wafers T are carried in and out of the carry-in / out station 2. Then, these cassettes Cw, Cs, and Ct are freely mounted in a row in the Y-axis direction on the cassette mounting table 10.

Next, while rotating the chuck 401 as shown in FIG. 28 (c), the second etching solution E2 is supplied from the second nozzle 404 to the peripheral edge of the surface Sa of the support wafer S, and the surface Sa (silicon) is supplied. The peripheral part of the part) is etched. At this time, the second etching solution E2 for TMAH as described above, Choline, KOH, etc. is used, the surface Sa is etched oxide film Fs is not etched, the oxide film Fs as a mask. Further, the surface Sa is etched by, for example, several μm in the thickness direction.

Claims (20)

It is a processing system that processes the processing target.
A reformer that forms an internal surface reforming layer in the surface direction inside the processing object,
It has a separation device that separates the object to be treated from the internal surface modification layer as a base point.
The reformer
A laser irradiation unit that irradiates a plurality of laser beams inside the processing object,
It has a moving mechanism that relatively moves the laser irradiation unit and the processing object.
A processing system in which the plurality of laser beams from the laser irradiation unit are moved relative to the processing target by the moving mechanism to form the internal surface modification layer. The laser irradiation unit has a plurality of laser heads that irradiate the laser beam.
The reformer
In a state where a plurality of the laser heads are arranged at different positions in the radial direction of the processing target body, the laser beam from the laser head is sent by the moving mechanism to the center of the processing target body with respect to the processing target body. Rotate relative to the axis,
After that, the laser head is moved in the radial direction relative to the processing target by the moving mechanism.
The first aspect of the present invention, wherein the internal surface modification layer is formed by repeatedly rotating the laser beam relative to the processing object and moving the laser head relative to the processing object. Processing system. The laser irradiation unit has a plurality of laser heads that irradiate the laser beam.
In the reformer, the laser light from the laser head is sent to the processing object by the moving mechanism in a state where the plurality of laser heads are arranged at different positions in the radial direction of the processing object. Claim 1 to form the internal surface modification layer by moving the laser head in the radial direction relative to the processing object while rotating the center of the processing object relative to the axis. The processing system described in. The processing system according to claim 2 or 3, wherein the reformer adjusts the frequency of the laser light from the plurality of laser heads according to the radial positions of the plurality of laser heads. The processing object is divided into a plurality of areas and is divided into a plurality of areas.
The laser irradiation unit has a plurality of laser heads that irradiate the laser beam.
A plurality of the laser heads are arranged in each of the areas.
The processing system according to claim 1, wherein the reforming apparatus moves the laser light from the laser head relative to the area by the moving mechanism to form the internal surface reforming layer. The plurality of areas are partitioned by the center line of the processing target body, and the plurality of areas are partitioned by the center line of the processing target body.
The reformer
The moving mechanism causes the laser beam from the laser head to move relative to one area.
The moving mechanism rotates the laser head relative to the processing target body about the center of the processing target body, and moves the laser head to the other area adjacent to the one area.
The processing system according to claim 5, further comprising repeatedly moving the laser beam and moving the laser head with respect to the one area to form the internal surface modification layer. The laser irradiation unit irradiates another laser beam in the thickness direction along the boundary between the peripheral portion and the central portion of the object to be removed to form the peripheral modification layer. The processing system according to any one of claims 1 to 6, wherein the processing system comprises. The processing system according to any one of claims 1 to 7, wherein the separation device has a heating mechanism for heating the internal surface modification layer. The processing system according to claim 8, wherein the separation device has a cooling mechanism for cooling the processing object. The reformer forms the internal surface reforming layer inside the first processing target body, and forms the reforming layer.
The separation device separates the first processing target from the internal surface modification layer as a base point.
The processing system provides an interface treatment apparatus that performs a desired treatment at an interface where the first processing target body and the second processing target body are joined at a peripheral portion of the removal target of the first processing target body. The processing system according to any one of claims 1 to 9. The reformer is radially inward of the position corresponding to the end of the interface treated by the interface treatment device, along the boundary between the peripheral edge and the central portion of the first processing object. The treatment system according to claim 10, wherein a peripheral reforming layer is formed inside the first treatment target body. It is a processing method that processes the processing target.
Forming an internal surface modification layer in the surface direction inside the treatment object, and
It has the function of separating the object to be treated from the internal surface modification layer as a base point.
When forming the internal surface modification layer, the laser irradiation unit irradiates the inside of the processing target body with a plurality of laser beams, and the moving mechanism makes the plurality of laser lights relative to the processing target body. A treatment method in which the inner surface modified layer is formed by moving the inner surface. The laser irradiation unit has a plurality of laser heads that irradiate the laser beam.
When forming the internal surface modification layer,
In a state where a plurality of the laser heads are arranged at different positions in the radial direction of the processing target body, the laser beam from the laser head is sent by the moving mechanism to the center of the processing target body with respect to the processing target body. Rotate relative to the axis,
After that, the laser head is moved in the radial direction relative to the processing target by the moving mechanism.
The process according to claim 12, wherein the internal surface modification layer is formed by repeatedly rotating the laser beam relative to the processing object and moving the laser head relative to the processing object. Method. The laser irradiation unit has a plurality of laser heads that irradiate the laser beam.
When forming the internal surface modification layer, the laser light from the laser head is emitted by the moving mechanism in a state where the plurality of laser heads are arranged at different positions in the radial direction of the processing object. The laser head is moved in the radial direction relative to the processing target while rotating relative to the center of the processing target with respect to the processing target, and the internal surface modification layer is formed. 12. The processing method according to claim 12. 13. Processing method. The processing object is divided into a plurality of areas and is divided into a plurality of areas.
The laser irradiation unit has a plurality of laser heads that irradiate the laser beam.
A plurality of the laser heads are arranged in each of the areas.
The claim that the internal surface modified layer is formed by moving the laser light from the laser head relative to the area by the moving mechanism. 12. The processing method according to 12. The plurality of areas are partitioned by the center line of the processing target body.
When forming the internal surface modification layer,
The moving mechanism causes the laser beam from the laser head to move relative to one area.
The moving mechanism rotates the laser head relative to the processing target body about the center of the processing target body, and moves the laser head to the other area adjacent to the one area.
The processing method according to claim 16, wherein the movement of the laser beam and the movement of the laser head with respect to the one area are repeatedly performed to form the internal surface modification layer. The laser irradiation unit has a laser head for peripheral modification and has a laser head.
When forming the internal surface modification layer, another laser beam is irradiated from the peripheral edge modification laser head in the thickness direction along the boundary between the peripheral edge portion and the central portion of the treatment target body to be removed. The treatment method according to any one of claims 12 to 17, wherein a peripheral modification layer is formed. When the inner surface modification layer is formed, the inner surface modification layer is formed inside the first treatment target body, and when the treatment target body is separated, the inner surface modification layer is formed. The first processing target body is separated from the base point, and the first processing target body is separated.
12. The treatment method claims 12 that a desired treatment is performed on the interface where the first processing target body and the second processing target body are joined at the peripheral portion of the removal target of the first processing target body. The processing method according to any one of 18 to 18. When forming the internal surface modification layer, the peripheral portion and the center of the first treatment target body are radially inward from the position corresponding to the end portion of the interface on which the desired treatment has been performed. The treatment method according to claim 19, wherein a peripheral modification layer is formed inside the first treatment target body along a boundary with the portion.

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