JP7129558B2 - Processing equipment and processing method - Google Patents

Description

The present disclosure relates to processing apparatuses and processing methods.

Patent Literature 1 discloses a method of processing a wafer having a plurality of devices formed on its front surface. In this processing method, after forming an altered layer by irradiating a laser beam between the front side and the back side of the wafer, the back side wafer on the back side from the altered layer and the front side wafer on the front side from the altered layer are formed. and separate. In addition, the backside wafer is recycled.

Japanese Unexamined Patent Application Publication No. 2010-21398

A technique according to the present disclosure separates an object to be processed and efficiently uses the separated object to be processed.

One aspect of the present disclosure is a processing apparatus for processing a processing wafer, which is an object to be processed, comprising: a chuck holding a superposed wafer in which the processing wafer and a support wafer are bonded ; A peripheral edge laser beam is irradiated along the boundary between the peripheral edge portion and the central portion of the wafer to be processed to form a peripheral edge modified layer, and an inner surface laser beam is irradiated along the planar direction of the wafer to be processed to irradiate the inner surface. The processing wafer is separated into a first separated wafer and a second separated wafer based on the modified portion for forming the modified layer, the peripheral edge modified layer and the inner surface modified layer, and separated from the supporting wafer. a separation section for separating the second separation wafer; and a control section for controlling the reforming section and the separation section . and controlling the modified portion such that the position of the upper end of the inner surface modified layer is the same as or higher than the position of the uppermost end of the peripheral edge modified layer.

According to the present disclosure, an object to be processed can be separated, and the separated object to be processed can be efficiently used.

1 is a plan view schematically showing the outline of the configuration of a wafer processing system according to this embodiment; FIG. 1 is a side view schematically showing the outline of the configuration of a wafer processing system according to this embodiment; FIG. FIG. 4 is a side view showing the outline of the configuration of the superposed wafer; FIG. 4 is a side view schematically showing the configuration of part of the superposed wafer; It is a top view which shows the outline of a structure of a reformer. It is a side view which shows the outline of a structure of a reformer. FIG. 2 is a flowchart showing main steps of wafer processing according to the embodiment; FIG. 4 is an explanatory diagram of main steps of wafer processing according to the present embodiment; FIG. 10 is an explanatory view showing how a modified peripheral layer is formed on a wafer to be processed; FIG. 10 is an explanatory diagram showing a state in which a peripheral modified layer is formed on a processed wafer; It is explanatory drawing which shows a mode that an internal surface modification layer is formed in a process wafer. It is explanatory drawing which shows a mode that an internal surface modification layer is formed in a process wafer. FIG. 4 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to the present embodiment; It is explanatory drawing which shows a mode that a process wafer is isolate|separated. FIG. 11 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to another embodiment; FIG. 11 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to another embodiment; FIG. 11 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to another embodiment; FIG. 11 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to another embodiment; FIG. 11 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to another embodiment; FIG. 11 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to another embodiment; FIG. 11 is an explanatory diagram showing the positional relationship between a peripheral edge modified layer and an inner surface modified layer according to another embodiment; FIG. 5 is an explanatory diagram of main steps of wafer processing according to another embodiment; FIG. 10 is a plan view schematically showing the outline of the configuration of a wafer processing system according to another embodiment ; FIG. 5 is an explanatory diagram of main steps of wafer processing according to another embodiment;

2. Description of the Related Art In the manufacturing process of semiconductor devices, a semiconductor wafer having a plurality of devices formed on its surface (hereinafter referred to as a wafer) is thinned. There are various methods for thinning the wafer, but there are, for example, a method of grinding the back surface of the wafer and a method of separating the wafer as disclosed in Patent Document 1. In particular, according to the method disclosed in Patent Document 1, the devices constituting the separated front side wafer can be commercialized, and the back side wafer can be recycled.

Here, a modified layer (modified layer) remains on the surface of the separated back side wafer, and it cannot be recycled (reused) as it is. However, Patent Document 1 does not disclose or suggest how to treat the modified layer of the backside wafer. Furthermore, no consideration has been given to a method for efficiently reusing the backside wafer. Therefore, there is room for improvement in conventional wafer processing in separating wafers, thinning them, and reusing the separated wafers.

A technique according to the present disclosure separates an object to be processed and efficiently uses the separated object to be processed. A wafer processing system as a processing apparatus and a wafer processing method as a processing method according to the present embodiment will be described below with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

First, the configuration of the wafer processing system according to this embodiment will be described. FIG. 1 is a plan view schematically showing the outline of the configuration of a wafer processing system 1. As shown in FIG. FIG. 2 is a side view schematically showing the outline of the configuration of the wafer processing system 1. As shown in FIG.

In the wafer processing system 1, as shown in FIGS. 3 and 4, processing is performed on a superposed wafer T in which a processing wafer W as an object to be processed and a support wafer S are bonded together. Then, in the wafer processing system 1, the wafer W to be processed is thinned while the peripheral edge portion We of the wafer W to be processed is removed. Hereinafter, in the processing 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 processing wafer W is called a surface Sa, and the surface opposite to the surface Sa is called a back surface Sb.

The processing wafer W is a semiconductor wafer such as a silicon substrate, and a device layer (not shown) including a plurality of devices is formed on the surface Wa. Further, an oxide film F such as a SiO ₂ film (TEOS film) is further formed on the device layer. The peripheral edge portion We of the processing wafer W is chamfered, and the thickness of the cross section of the peripheral edge portion We decreases toward its tip. Further, the peripheral edge portion We is a portion to be removed in the edge trim, and is in the range of 1 mm to 5 mm in the radial direction from the outer end portion of the processing wafer W, for example.

In the wafer processing system 1 of the present embodiment, the wafer W to be processed is separated from the superposed wafer T. As shown in FIG. In the following description, the separated processing wafer W on the front surface Wa side is referred to as a first separated wafer W1 as a first processing target, and the separated processing wafer W on the back surface Wb side is referred to as a second processing target. It is referred to as a second separated wafer W2 as a body. The first separated wafer W1 has a device layer D and is manufactured. The second separated wafer W2 is reused. The first separated wafer W1 indicates the processing wafer W supported by the support wafer S, and the support wafer S is sometimes called the first separated wafer W1. A surface separated by the first separation wafer W1 is referred to as a separation surface W1a, and a surface separated by the second separation wafer W2 is referred to as a separation surface W2a.

Also, in FIG. 3, the illustration of the oxide film F is omitted in order to avoid complication of the illustration. Similarly, in other drawings used in the following description, the illustration of the oxide film F may be omitted.

The support wafer S is a wafer that supports the processing wafer W, and is, for example, a silicon wafer. An oxide film (not shown) is formed on the surface Sa of the support wafer S. As shown in FIG. Further, the support wafer S functions as a protective material that protects the devices on the surface Wa of the processing wafer W. As shown in FIG. In addition, when a plurality of devices are formed on the surface Sa of the support wafer S, a device layer (not shown) is formed on the surface Sa similarly to the processing wafer W. FIG.

In the wafer processing system 1 of the present embodiment, in addition to the above-described separation processing (thinning processing) of the processing wafer W, the separation processing causes the peripheral edge portion We of the processing wafer W to have a sharply pointed shape (so-called knife-edge shape). An edge trimming process is performed to prevent this from occurring. In this edge trim process, if the processing wafer W and the support wafer S are bonded at the peripheral edge portion We of the processing wafer W, the peripheral edge portion We may not be properly removed. Therefore, at the interface between the processing wafer W and the support wafer S, there are a bonded area Aa where the oxide film F and the surface Sa of the support wafer S are bonded, and an unbonded area Ab which is a radially outer area of the bonded area Aa. Form. The presence of the unbonded region Ab in this manner allows the peripheral portion We to be appropriately removed. The outer end of the joint region Aa is positioned slightly radially outward from the inner end of the peripheral edge We to be removed.

Note that the unbonded region Ab is formed, for example, before bonding. That is, before bonding, the outer peripheral portion of the oxide film F is subjected to a process of reducing the bonding strength with respect to the surface Sa of the support wafer S. As shown in FIG. Specifically, the outer peripheral surface layer may be removed by polishing, wet etching, or the like. Alternatively, the surface of the outer peripheral portion may be made hydrophobic or roughened with a laser.

Also, the unbonded region Ab may be formed, for example, after bonding. For example, by irradiating the outer peripheral portion of the oxide film F with a laser beam after bonding, it is possible to reduce the bonding strength to the surface Sa of the support wafer S. In such a case, generation of debris (particles) can be suppressed because laser light is irradiated after bonding. Even if voids remain in the peripheral portion We when the processing wafer W and the support wafer S are bonded together, the voids can be eliminated by forming the unbonded region Ab using laser light as in the present embodiment. It is also possible to remove it.

As shown in FIG. 1, the wafer processing system 1 has a configuration in which a loading/unloading station 2 and a processing station 3 are integrally connected. The loading/unloading station 2 and the processing station 3 are arranged side by side from the X-axis negative direction side toward the positive direction side. The loading/unloading station 2 loads/unloads cassettes Ct, Cw1, and Cw2 each capable of accommodating, for example, a plurality of superposed wafers T, a plurality of first separated wafers W1, and a plurality of second separated wafers W2. be The processing station 3 includes various processing devices for performing desired processing on the superposed wafer T and the separated wafers W1 and W2.

Although the cassette Ct and the cassette Cw1 are provided separately in this embodiment, they may be the same cassette. That is, the cassette housing the unprocessed stacked wafers T and the processed first separated wafer W1 cassette may be used in common.

The loading/unloading station 2 is provided with a cassette mounting table 10 . In the illustrated example, a plurality of, for example, three cassettes Ct, Cw1, and Cw2 can be mounted in a line on the cassette mounting table 10 in the Y-axis direction. The number of cassettes Ct, Cw1, and Cw2 to be placed on the cassette placing table 10 is not limited to the number in this embodiment, and can be arbitrarily determined.

The loading/unloading station 2 is provided with a wafer transfer area 20 adjacent to the cassette mounting table 10 on the X-axis positive direction side of the cassette mounting table 10 . The wafer transfer area 20 is provided with a wafer transfer device 22 which is movable on a transfer path 21 extending in the Y-axis direction. The wafer transfer device 22 has two transfer arms 23, 23 for holding and transferring the superposed wafer T and the separated wafers W1, W2. Each transport arm 23 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. In addition, the configuration of the transport arm 23 is not limited to the present embodiment, and may take any configuration. The wafer transfer device 22 is configured to transfer the superimposed wafers T and the separated wafers W1 and W2 to the cassettes Ct, Cw1 and Cw2 of the cassette mounting table 10 and the transition device 30 which will be described later.

The loading/unloading station 2 is provided with a transition device 30 for transferring the overlapped wafer T and the separated wafers W1 and W2 adjacent to the wafer transfer area 20 on the X-axis positive direction side of the wafer transfer area 20 . there is

The processing station 3 is provided with a wafer transfer area 40 and a processing block 50 . The processing block 50 is arranged on the Y-axis negative direction side of the wafer transfer area 40 .

The wafer transfer area 40 is provided with a wafer transfer device 42 which is movable on a transfer path 41 extending in the X-axis direction. The wafer transfer device 42 has two transfer arms 43, 43 for holding and transferring the superposed wafer T and the separated wafers W1, W2. Each transport arm 43 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. In addition, the configuration of the transport arm 43 is not limited to this embodiment, and may take any configuration. The wafer transfer device 42 is configured to transfer the superposed wafer T and the separated wafers W1 and W2 to the transition device 30 and the processing devices of the processing block 50 .

The processing block 50 has an etching device 60 as an etching section, a reversing device 61 as a reversing section, a cleaning device 62 as a cleaning section, a separating device 63 as a separating section, and a reforming device 64 . The etching devices 60 are arranged in two rows in the X-axis direction and three stages in the vertical direction on the loading/unloading station 2 side of the processing block 50 . That is, in this embodiment, six etching apparatuses 60 are provided. The reversing device 61 and the two cleaning devices 62 are stacked vertically downward on the X-axis positive direction side of the etching device 60 . The separating device 63 and the reforming device 64 are stacked vertically downward on the X-axis positive direction side of the reversing device 61 and the cleaning device 62 . The number and arrangement of the etching device 60, the reversing device 61, the cleaning device 62, the separation device 63, and the reforming device 64 are not limited to these.

The etching device 60 etches the separation surface W1a of the first separation wafer W1 or the separation surface W2a of the second separation wafer W2. For example, an etching (chemical solution) is supplied to the separation surface W1a or the separation surface W2a to wet-etch the separation surface W1a or the separation surface W2a. For example, HF, HNO ₃ , H ₃ PO ₄ , TMAH, Choline, KOH, or the like is used as the etchant.

The reversing device 61 reverses the front and back surfaces of the second separated wafer W2 separated by the separating device 63 . The configuration of the reversing device 61 is arbitrary.

The cleaning device 62 cleans the separation surface W1a of the first separation wafer W1 or the separation surface W2a of the second separation wafer W2. For example, a brush is brought into contact with the separation surface W1a or the separation surface W2a to scrub-clean the separation surface W1a or the separation surface W2a. A pressurized cleaning liquid may be used for cleaning the separation surface W1a or the separation surface W2a.

The separating device 63 separates the processing wafer W into a first separated wafer W1 and a second separated wafer W2 based on the modified peripheral layer and the inner surface modified layer formed by the modifying device 64 .

The modifying device 64 irradiates the inside of the processing wafer W with a laser beam to form a peripheral edge modified layer and an inner surface modified layer. A specific configuration of the reformer 64 will be described later.

The wafer processing system 1 described above is provided with a controller 70 as a controller. The control device 70 is, for example, a computer and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the superposed wafer T and the separated wafers W1 and W2 in the wafer processing system 1. FIG. The program storage unit also stores a program for controlling the operation of drive systems such as the above-described various processing devices and transfer devices to realize wafer processing, which will be described later, in the wafer processing system 1 . The above program may be recorded in a computer-readable storage medium H and installed in the control device 70 from the storage medium H.

Next, the above reformer 64 will be described. FIG. 5 is a plan view showing the outline of the structure of the reformer 64. As shown in FIG. FIG. 6 is a side view showing a schematic configuration of the reformer 64. As shown in FIG.

The reformer 64 has a chuck 100 that holds the superposed wafer T on its upper surface. The chuck 100 sucks and holds the support wafer S with the processing wafer W on the upper side and the support wafer S on the lower side. A chuck 100 is supported by a slider table 102 via an air bearing 101 . A rotating mechanism 103 is provided on the lower surface side of the slider table 102 . The rotation mechanism 103 incorporates, for example, a motor as a drive source. The chuck 100 is rotatable about a vertical axis via an air bearing 101 by a rotating mechanism 103 . The slider table 102 is configured to be movable along rails 105 provided on a base 106 and extending in the Y-axis direction by means of a moving mechanism 104 provided on the underside of the slider table 102 . Although the driving source of the moving mechanism 104 is not particularly limited, for example, a linear motor is used.

Above the chuck 100, a laser head 110 is provided as a modified section. The laser head 110 has a lens 111 . The lens 111 is a cylindrical member provided on the lower surface of the laser head 110 and irradiates the processing wafer W held by the chuck 100 with laser light.

The laser head 110 is a high-frequency pulsed laser beam oscillated from a laser beam oscillator (not shown), and has a wavelength that is transparent to the wafer W to be processed. The light is condensed and irradiated at a predetermined position. As a result, the portion of the wafer W to be processed where the laser beam is condensed is modified to form a peripheral edge modified layer and an inner surface modified layer.

The laser head 110 is supported by a support member 112 . The laser head 110 is configured to be vertically movable by a lifting mechanism 114 along a rail 113 extending in the vertical direction. Also, the laser head 110 is configured to be movable in the Y-axis direction by a moving mechanism 115 . Note that the lifting mechanism 114 and the moving mechanism 115 are each supported by a support column 116 .

A macro camera 120 and a micro camera 121 are provided above the chuck 100 and on the positive Y-axis side of the laser head 110 . For example, the macro camera 120 and the micro camera 121 are integrated, and the macro camera 120 is arranged on the Y-axis positive side of the micro camera 121 . The macro camera 120 and the micro camera 121 are configured to be vertically movable by an elevating mechanism 122 and further movable in the Y-axis direction by a moving mechanism 123 .

The macro camera 120 images the outer edge of the processing wafer W (overlapping wafer T). The macro camera 120 includes, for example, a coaxial lens, emits visible light such as red light, and receives reflected light from the object. For example, the imaging magnification of the macro camera 120 is 2 times.

The micro camera 121 images the periphery of the wafer W to be processed, and images the boundary between the bonded area Aa and the unbonded area Ab. The micro camera 121 has, for example, a coaxial lens, irradiates infrared light (IR light), and receives reflected light from an object. For example, the imaging magnification of the micro camera 121 is 10 times, the field of view is about 1/5 that of the macro camera 120, and the pixel size is about 1/5 that of the macro camera 120. FIG.

Next, wafer processing performed using the wafer processing system 1 configured as described above will be described. FIG. 7 is a flow chart showing the main steps of wafer processing. FIG. 8 is an explanatory diagram of main steps of wafer processing. In this embodiment, the processing wafer W and the support wafer S are bonded to each other in a bonding device (not shown) outside the wafer processing system 1 to form a superimposed wafer T in advance.

First, a cassette Ct housing a plurality of superposed wafers T shown in FIG.

Next, the superposed wafer T in the cassette Ct is taken out by the wafer transfer device 22 and transferred to the transition device 30 . Subsequently, the wafer transfer device 42 takes out the superposed wafer T from the transition device 30 and transfers it to the reforming device 64 . In the reformer 64, as shown in FIG. 8(b), a peripheral edge reformed layer M1 is formed inside the processing wafer W (step A1 in FIG. 7), and furthermore, as shown in FIG. 8(c), the inner surface is reformed. A layer M2 is formed (step A2 in FIG. 7). The modified peripheral layer M1 serves as a base point for removing the peripheral portion We in the edge trim. The inner surface modified layer M2 serves as a starting point for separating and thinning the wafer W to be processed.

In the reforming device 64 , first, the superposed wafer T is loaded from the wafer transfer device 42 and held by the chuck 100 . Next, chuck 100 is moved to the macro-alignment position. The macro alignment position is the position at which the macro camera 120 can image the outer edge of the wafer W to be processed.

Next, the macro camera 120 captures an image of the outer edge of the processing wafer W in the circumferential direction of 360 degrees. The captured image is output from macro camera 120 to control device 70 .

The controller 70 calculates a first eccentricity between the center Cc of the chuck 100 and the center Cw of the processing wafer W from the image of the macro camera 120 . Further, the controller 70 calculates the movement amount of the chuck 100 based on the first eccentricity so as to correct the Y-axis component of the first eccentricity. The chuck 100 moves in the Y-axis direction based on this calculated movement amount, and moves the chuck 100 to the micro-alignment position. The micro-alignment position is a position where the micro-camera 121 can image the periphery of the wafer W to be processed. Here, as described above, since the field of view of the micro camera 121 is as small as about 1/5 that of the macro camera 120, if the Y-axis component of the first eccentricity is not corrected, the peripheral edge of the wafer W to be processed will not be visible to the micro camera. 121 and cannot be captured by the micro camera 121 . Therefore, the correction of the Y-axis component based on the first amount of eccentricity can be said to move the chuck 100 to the micro-alignment position.

Next, the micro camera 121 captures an image of the boundary between the bonded area Aa and the unbonded area Ab at 360 degrees in the circumferential direction of the wafer W to be processed. The captured image is output from the micro camera 121 to the control device 70 .

The control device 70 calculates a second eccentricity between the center Cc of the chuck 100 and the center Ca of the bonding area Aa from the image of the micro camera 121 . Further, the controller 70 determines the position of the chuck 100 with respect to the modified peripheral layer M1 based on the second eccentricity so that the center of the bonding area Aa and the center of the chuck 100 are aligned.

Next, as shown in FIGS. 9 and 10, a laser beam L1 (periphery laser beam L1) is emitted from the laser head 110 to form a modified peripheral layer M1 on the boundary between the peripheral portion We and the central portion Wc of the wafer W to be processed. is formed (step A1 in FIG. 7). The modified peripheral layer M1 is formed radially inward of the outer end of the joint region Aa.

In step A1, the rotating mechanism 103 rotates the chuck 100 and the moving mechanism 104 rotates the chuck 100 so that the center of the bonding area Aa coincides with the center of the chuck 100 according to the position of the chuck 100 determined by the control device 70. The chuck 100 is moved in the Y-axis direction. At this time, the rotation of the chuck 100 and the movement in the Y-axis direction are synchronized.

Then, while rotating and moving the chuck 100 (processing wafer W) in this manner, the inside of the processing wafer W is irradiated with the laser light L1 from the laser head 110 . That is, the modified peripheral layer M1 is formed while correcting the second eccentricity. Then, the modified peripheral layer M1 is formed in an annular shape concentrically with the bonding area Aa. Therefore, after that, the peripheral portion We can be appropriately removed from the modified peripheral layer M1 as a starting point.

In this example, when the second eccentricity has an X-axis component, the chuck 100 is rotated while moving in the Y-axis direction to correct the X-axis component. On the other hand, if the second eccentricity does not have an X-axis component, chuck 100 need only be moved in the Y-axis direction without being rotated.

In step A1, as the modified peripheral layer M1, for example, a lower modified peripheral layer M11 and an upper modified peripheral layer M12 are formed in the height direction (thickness direction) perpendicular to the surface direction of the wafer W to be processed. do. Specifically, after forming the modified peripheral layer M11, the modified peripheral layer M12 is formed. For example, when the upper peripheral modified layer M12 is formed first, when the laser beam L1 is irradiated when forming the lower peripheral modified layer M11 later, the laser beam L1 is obstructed by the modified peripheral layer M12. There is a risk. Therefore, in the present embodiment, the lower edge modified layer M11 is first formed. Note that the number of stages of the modified peripheral layer M1 is not limited to this, and may be one stage or three or more stages.

Further, a crack (hereinafter referred to as a crack C1) is formed from each of the modified peripheral layer M11 and the modified peripheral layer M12. A crack C1 from the peripheral modified layer M11 extends downward and reaches the surface Wa. Further, the crack C1 extending upward from the modified peripheral layer M11 and the crack C1 extending downward from the modified peripheral layer M12 are connected. Note that the crack C1 does not extend upward from the modified peripheral layer M12. Further, the cracks C1 extending from the modified peripheral layer M11 are connected in the circumferential direction, and the cracks C1 extending from the modified peripheral layer M12 are also connected in the circumferential direction.

Next, as shown in FIGS. 11 to 13, laser light L2 (inner surface laser light L2) is emitted from the laser head 110 to form the inner surface modified layer M2 along the surface direction (see FIG. 7). Step A2). A black arrow shown in FIG. 12 indicates the rotation direction of the chuck 100 .

In step A2, while the chuck 100 (process wafer W) is rotated once (360 degrees), the inside of the process wafer W is irradiated with the laser light L2 from the laser head 110 to form an annular inner surface modified layer M2. do. After that, the laser head 110 is moved radially inward of the processing wafer W (in the Y-axis direction). The formation of the annular inner surface modified layer M2 and the radially inward movement of the laser head 110 are repeated to form the inner surface modified layer M2 in the planar direction.

Although the laser head 110 is moved in the Y-axis direction in forming the inner surface modified layer M2 in this embodiment, the chuck 100 may be moved in the Y-axis direction. Although the chuck 100 is rotated to form the inner surface modified layer M2, the laser head 110 may be moved and rotated relative to the chuck 100. FIG.

In step A2, a plurality of annular inner surface modified layers M2 are formed in the radial direction as described above. That is, as shown in FIG. 13, the inner surface modified layer M2 has inner surface modified layers M21, M22, M23, M24, M25, etc. from the radially outer side to the inner side. The number of inner surface modified layers M2 in the radial direction is arbitrary.

Further, cracks (hereinafter referred to as cracks C2) are formed from each of the plurality of inner surface modified layers M2. A crack C2 from the inner surface modified layer M21 extends radially outward and reaches the peripheral edge modified layer M12. Further, the crack C2 extending radially inward from the inner surface modified layer M21 and the crack C2 extending radially outward from the inner surface modified layer M22 are connected. In this way, the cracks C2 radially extending from the adjacent inner surface modified layers M2, M2 are connected. The cracks C2 extending from each inner surface modified layer M2 are connected in the circumferential direction.

Here, the positional relationship between the peripheral modified layer M1 formed in step A1 and the inner surface modified layer M2 formed in step A2 will be described with reference to FIG. First, regarding the positional relationship in the radial direction (surface direction), the inner surface modified layer M2 is formed radially inside the peripheral edge modified layer M1. That is, the inner surface modified layer M21 is formed radially inside the peripheral edge modified layer M11.

Next, the positional relationship in the height direction will be described. When the wafer W to be processed is separated at the desired separation planes W1a and W2a, the position of the inner surface modified layer M2 is naturally determined, so the positional relationship in the height direction is determined by the position where the peripheral edge modified layer M1 is formed. . In this embodiment, the position of the upper end of the upper peripheral edge modified layer M12 is at the same height as the positions of the upper ends of the inner surface modified layers M2 (M21 to M25) (dotted line in FIG. 13). In this embodiment, the separation planes W1a and W2a of the wafer W to be processed (the dashed-dotted line in FIG. 13) are the center position of the inner surface modified layer M2 in the height direction of the wafer W to be processed.

Since the second separation wafer W2 after separation is reused as will be described later, it is necessary to etch the separation surface W2a so that no modified layer remains on the separation surface W2a. If the upper end of the peripheral edge modified layer M12 is higher than the upper edge of the inner surface modified layer M2, the separation surface W2a is etched by the difference between the upper edge of the peripheral edge modified layer M12 and the inner surface modified layer M2. It has to be done, and waste occurs. On the other hand, if the position of the upper end of the modified peripheral layer M12 and the position of the upper end of the inner surface modified layer M2 are set at the same height as in the present embodiment, the modified peripheral layer M12 and the modified inner surface layer M2 can be set at the position for etching, and the waste described above does not occur.

How much the peripheral modified layer M1 (inner surface modified layer M2) spreads from the converging position of the laser beam L1 (laser beam L2) depends on, for example, the energy of the laser beam L1, the pulse width, and the degree of correction of convergence/dispersion. Kimaru. The pulse width indicates the irradiation time of one laser beam L1, and the larger the pulse width is, the larger the edge modified layer M1 is. The degree of correction of convergence is to correct whether the laser light L1 is concentrated at one point or diffused. If the laser light L1 is diffused, the peripheral modified layer M1 also becomes larger.

Next, when the inner surface modified layer M2 is formed on the processing wafer W, the superposed wafer T is unloaded by the wafer transfer device .

Next, the superposed wafer T is transferred to the separation device 63 by the wafer transfer device 42 . As shown in FIG. 8(d), the separating device 63 separates the wafer W to be processed into a first separated wafer W1 and a second separated wafer W2 based on the peripheral edge modified layer M1 and the inner surface modified layer M2. (Step A3 in FIG. 7). At this time, the peripheral portion We is also removed from the first separated wafer W1.

In step A3, among the stacked wafers T, the suction plate 130 sucks and holds the process wafer W, and the chuck 131 sucks and holds the support wafer S, as shown in FIG. 14(a). Next, as shown in FIG. 14(b), a wedge-shaped blade 132, for example, is inserted into the interface between the processing wafer W and the support wafer S, and the separation planes W1a and W2a serve as boundaries between the first separation wafer W1 and the first separation wafer W1. The second separated wafer W2 is trimmed. Thereafter, as shown in FIG. 14(c), the suction plate 130 is lifted while holding the second separation wafer W2 by suction, and the first separation wafer W1 is separated from the second separation wafer W2. separate.

At this time, a pressure sensor (not shown) provided on the suction plate 130 measures the pressure for sucking the second separated wafer W2. By this pressure measurement, it is possible to detect the presence or absence of the second separated wafer W2 and confirm whether or not the second separated wafer W2 has been separated from the first separated wafer W1.

In addition, the method of separating the processing wafer W is not limited to this embodiment. In the present embodiment, the wafer W to be processed is separated only by lifting the suction plate 130, but the wafer W to be processed may be separated by lifting the suction plate 130 while rotating the suction plate 130. FIG. Alternatively, for example, a tape (not shown) may be used instead of the suction plate 130 to hold and separate the processing wafer W by the tape. Furthermore, before the processing wafer W is adsorbed and held by the adsorption plate 130, for example, ultrasonic waves may be applied to at least the internal surface modified layer M2 of the processing wafer W, or the internal surface modified layer M2 may be heated. good too. In such a case, it becomes easier to separate the processing wafer W with the inner surface modified layer M2 as a base point.

Next, the first separated wafer W1 and the second separated wafer W2 separated by the separation device 63 are subjected to different processes.

The second separated wafer W 2 is transferred to the reversing device 61 by the wafer transfer device 42 . The reversing device 61 reverses the front and back surfaces of the second separated wafer W2 (step A4 in FIG. 7). That is, as shown in FIG. 8(e), the separation surface W2a of the second separation wafer W2 faces upward.

Next, the second separated wafer W2 is transferred to the cleaning device 62 by the wafer transfer device 42. As shown in FIG. In the cleaning device 62, the separation surface W2a of the second separation wafer W2 is scrub-cleaned as shown in FIG. 8(e) (step A5 in FIG. 7).

In step A5, a spin chuck (not shown) rotates and holds the second separated wafer W2. For example, pure water is supplied from the Then, the separation surface W2a is cleaned to remove particles from the separation surface W2a. After that, after the scrubbing jig 140 is retracted, the second separated wafer W2 is further rotated to spin dry the separated surface W2a.

Next, the second separated wafer W2 is transferred to the etching device 60 by the wafer transfer device 42. As shown in FIG. In the etching device 60, as shown in FIG. 8(f), the separation surface W2a of the second separation wafer W2 is wet-etched with the etchant E (step A6 in FIG. 7).

In step A6, while rotating and holding the second separated wafer W2 on a spin chuck (not shown), the etchant is applied to the center of the separation surface W2a from the nozzle 150 arranged above the second separated wafer W2. supply E. The separation surface W2a is etched by the etchant E, and the peripheral modified layer M1 and the inner surface modified layer M2 remaining on the separation surface W2a are removed. In addition, since the peripheral edge modified layer M1 and the inner surface modified layer M2 remain in the scrub cleaning in step A5, particles may be generated again if this state is left as it is. Particles are also removed.

Here, as described above, since the position of the upper end of the peripheral edge modified layer M12 and the position of the upper end of the inner surface modified layer M2 are at the same height, the amount of etching of the separation surface W2a can be minimized. can be done. Therefore, the consumption of the etchant E can be suppressed, and the time required for etching can be shortened.

In addition, a peripheral portion W2e remains on the second separated wafer W2. Since the etchant E is supplied from above in this state, the etchant E is stored in the space surrounded by the peripheral portion W2e to form a paddle. Therefore, the consumption of the etchant E can be further suppressed.

In step A6, after the separation surface W2a is thus etched, the supply of the etchant E from the nozzle 150 is stopped, the separation surface W2a is washed with pure water, and then the second separation wafer W2 is removed. Further rotation is performed to spin dry the separation surface W2a.

After that, the second separated wafer W<b>2 that has undergone all the processes is transferred to the cassette Cw<b>2 on the cassette mounting table 10 by the wafer transfer device 22 .

As described above, in parallel with steps A4 to A6 being performed on the second separated wafer W2, desired processing is performed on the first separated wafer W1.

That is, the first separated wafer W<b>1 separated by the separation device 63 is transferred to the cleaning device 62 by the wafer transfer device 42 . In the cleaning device 62, the separation surface W1a of the first separation wafer W1 is scrub-cleaned as shown in FIG. 8(g) (step A7 in FIG. 7). In step A7, pure water is supplied while the scrub jig 140 is brought into contact with the separation surface W1a from above to wash the separation surface W1a, as in step A5.

Next, the first separated wafer W1 is transferred to the etching device 60 by the wafer transfer device 42. As shown in FIG. In the etching apparatus 60, as shown in FIG. 8(h), the separation surface W1a of the first separation wafer W1 is wet-etched with the etchant E (step A8 in FIG. 7). In step A8, the peripheral modified layer M1 and the inner surface modified layer M2 remaining on the separation surface W1a are removed. Also, in step A8, the separation surface W1a is etched so that the first separation wafer W1 is thinned to a desired thickness.

After that, the first separated wafer W<b>1 that has undergone all the processes is transferred to the cassette Cw<b>1 on the cassette mounting table 10 by the wafer transfer device 22 . At this time, if the cassette Ct is empty, the first separated wafer W1 may be transferred to the cassette Ct. Thus, a series of wafer processing in the wafer processing system 1 is completed.

Outside the wafer processing system 1, the second separated wafer W2 to be reused is ground on the separation surface W2a side, and the peripheral edge portion W2e is removed. After that, the separated surface W2a of the ground second separated wafer W2 is washed to remove particles, and then the separated surface W2a is etched to remove grinding marks. Then, when the second separated wafer W2 is to be reused as, for example, a product wafer, the separated surface W2a is further polished (CMP). On the other hand, when the second separated wafer W2 is reused, for example, as a support wafer for supporting product wafers, it is used as it is.

Outside the wafer processing system 1, the separation surface W1a of the first separation wafer W1 to be manufactured is polished (CMP). In this embodiment, since the first separation wafer W1 is etched to the desired thickness in step A8 as described above, it is only necessary to polish the separation surface W1a. However, if the first separation wafer W1 does not have the desired thickness in step A8, the separation surface W1a is ground to the desired thickness outside the wafer processing system 1, for example. Thereafter, cleaning of the separation surface W1a, etching of the separation surface W1a, and polishing of the separation surface W1a are sequentially performed on the ground first separation wafer W1.

According to the above embodiment, steps A1 to A8 are performed, the wafer W to be processed is separated, and the separated surfaces W1a and W2a of the separated wafers W1 and W2 can be appropriately processed by cleaning, etching, etc., respectively. Therefore, the first separated wafer W1 having the device layer can be commercialized, and the second separated wafer W2 can be reused. Moreover, since these steps A1 to A8 are performed in one wafer processing system 1, wafer processing can be performed efficiently.

In the above-described embodiment, the order of steps A1 and A2 may be reversed, and after forming the inner surface modified layer M2, the peripheral edge modified layer M1 may be formed. However, when forming the peripheral modified layer M1, particularly the lower peripheral modified layer M11, there is a possibility that the laser beam L1 may be obstructed by the inner surface modified layer M2. It is preferable to form the inner surface modified layer M2 in step A2 after forming the peripheral edge modified layer M1 in step A2.

Further, according to the present embodiment, in steps A1 and A2, the peripheral edge is modified such that the position of the upper edge of the upper edge modified layer M12 is at the same height as the upper edge of the inner surface modified layer M2. A layer M1 and an internal surface modification layer M2 are formed. In such a case, when etching the separation surface W2a of the second separation wafer W2 in step A6, it is sufficient to etch up to the edges of the peripheral edge modified layer M12 and the inner surface modified layer M2, and the amount of etching can be minimized. can be done. Therefore, the consumption of the etchant E can be suppressed, and the time required for etching can be shortened.

When the modified peripheral layer M1 is formed in, for example, three or more stages, the position of the upper end of the uppermost modified peripheral layer M1 is at the same height as the position of the upper end of the inner surface modified layer M2. You should make it so that Even in such a case, the same effect as described above can be enjoyed.

Here, when the thickness H1 of the wafer W to be processed shown in FIG. If the layer M2 is formed to the same height, it can be reused as a product wafer. That is, even if the second separated wafer W2 after separation along the separation plane W2a is further subjected to etching, grinding, CMP, etc., a thickness of about 700 μm remains. In such a case, a device can be formed on the surface of the second separated wafer W2 for commercialization.

Further, when the thickness H1 of the wafer W to be processed is 775 μm, for example, and the height H2 of the separation surfaces W1a and W2a from the surface Wa is 100 μm, for example, the peripheral modified layer M12 and the inner surface modified layer M2 have the same height. It can be reused as a support wafer for supporting product wafers. That is, even if the second separated wafer W2 after separation along the separation plane W2a is subjected to further etching, grinding, etc., a thickness of about 600 μm remains. In such a case, the second separation wafer W2 can be used as a support wafer for supporting the product wafer in the temporary bonding process when thinning the product wafer.

The second separated wafer W2 can be reused as a product wafer having a device region having a plurality of devices formed on its surface and an outer peripheral surplus region surrounding the device region. In such a case, the separation surface W2a of the second separated wafer W2 processed by the wafer processing system 1 may not be ground, and the peripheral edge portion W2e may be left.

Next, another embodiment of the positional relationship between the peripheral modified layer M1 formed in step A1 and the inner surface modified layer M2 formed in step A2 will be described. 15 to 21 are explanatory diagrams showing the positional relationship between the modified peripheral layer M1 and the modified inner surface layer M2 according to other embodiments.

The radial positional relationship between the modified peripheral layer M1 and the inner surface modified layer M2 shown in FIGS. 15 to 17 is the same as the positional relationship shown in FIG. That is, the inner surface modified layer M2 (inner surface modified layer M21) is formed radially inward of the peripheral edge modified layer M1 (peripheral edge modified layer M12).

Regarding the positional relationship in the height direction between the modified peripheral layer M1 and the modified inner surface layer M2 shown in FIG. 15, the position of the upper end of the modified inner surface layer M2 is higher than the position of the upper end of the modified peripheral layer M12. Furthermore, the position of the upper end of the inner surface modified layer M2 is at the same height as the position of the apex of the crack C1 extending upward from the upper end of the peripheral edge modified layer M12.

Regarding the positional relationship in the height direction between the peripheral edge modified layer M1 and the inner surface modified layer M2 shown in FIG. is. However, the crack C1 extends slightly upward from the upper end of the modified peripheral layer M12.

Regarding the positional relationship in the height direction between the modified peripheral layer M1 and the modified inner surface layer M2 shown in FIG. 17, the position of the upper end of the modified inner surface layer M2 is higher than the position of the upper end of the modified peripheral layer M12. Furthermore, the position of the upper end of the inner surface modified layer M2 is higher than the position of the apex of the crack C1 extending upward from the upper end of the peripheral modified layer M12, and the cracks C1 and C2 are connected.

In any of the cases shown in FIGS. 15 to 17, when etching the separation surface W2a of the second separation wafer W2 in step A6, it is sufficient to etch up to the end of the inner surface modified layer M2, and the etching amount is minimized. can be kept to a limit. Therefore, the consumption of the etchant E can be suppressed, and the time required for etching can be shortened.

The radial positional relationship between the modified peripheral layer M1 and the inner surface modified layer M2 shown in FIGS. 18 to 21 is different from the positional relationship shown in FIGS. That is, the outermost inner surface modified layer M21 is formed at the same position in the radial direction as the peripheral modified layer M11 and above the peripheral modified layer M11.

Regarding the positional relationship in the height direction between the peripheral edge modified layer M1 and the inner surface modified layer M2 shown in FIG. It is the same height as the position of the upper end, and naturally higher than the position of the modified peripheral layer M11. Further, the inner surface modified layers M22 to M26, etc. located radially inside the inner surface modified layer M21 are formed at the same height. Furthermore, the crack C1 extending upward from the upper end of the peripheral modified layer M11 extends to the inner surface modified layer M21.

Regarding the positional relationship in the height direction between the peripheral edge modified layer M1 and the inner surface modified layer M2 shown in FIG. 19, the position of the upper end of the outermost inner surface modified layer M21 It is lower than the position of the upper end, and naturally higher than the position of the modified peripheral layer M11. Further, the inner surface modified layers M22 to M26, etc. located radially inside the inner surface modified layer M21 are formed at the same height. Furthermore, the position of the apex of the crack C1 extending upward from the upper end of the peripheral modified layer M11 is at the same height as the positions of the upper ends of the inner surface modified layers M22 to M26.

Regarding the positional relationship in the height direction between the peripheral edge modified layer M1 and the inner surface modified layer M2 shown in FIG. 20, the position of the upper end of the outermost inner surface modified layer M21 It is the same height as the position of the upper end, and naturally higher than the position of the modified peripheral layer M11. Further, the inner surface modified layers M22 to M26, etc. located radially inside the inner surface modified layer M21 are formed at the same height. Furthermore, the crack C1 extending upward from the upper edge of the modified peripheral layer M11 extends slightly above the upper edges of the inner surface modified layers M22 to M26.

Regarding the positional relationship in the height direction between the peripheral edge modified layer M1 and the inner surface modified layer M2 shown in FIG. 21, the position of the upper end of the outermost inner surface modified layer M21 It is lower than the position of the upper end, and naturally higher than the position of the modified peripheral layer M11. Further, the inner surface modified layers M22 to M26, etc. located radially inside the inner surface modified layer M21 are formed at the same height. Furthermore, the position of the apex of the crack C1 extending upward from the upper end of the peripheral edge modified layer M11 is lower than the positions of the upper ends of the inner surface modified layers M22 to M26, etc., and the cracks C1 and C2 are connected.

In any of the cases shown in FIGS. 18 to 21, when etching the separation surface W2a of the second separation wafer W2 in step A6, it suffices to etch at least the end portions of the inner surface modified layers M22 to M26. Etching amount can be minimized. Therefore, the consumption of the etchant E can be suppressed, and the time required for etching can be shortened.

In the case of the positional relationships shown in FIGS. 18 to 21, it is preferable to form the inner surface modified layer M2 after forming the peripheral edge modified layer M11. For example, when the inner surface modified layer M2 is formed first, if the laser light L1 is irradiated when forming the peripheral edge modified layer M11 later, the laser light L1 may be obstructed by the inner surface modified layer M2. be. Therefore, in the present embodiment, the inner surface modified layer M2 is first formed.

In the examples shown in FIGS. 13 and 15 to 21, the separation surfaces W1a and W2a of the processing wafer W (the dashed-dotted line in FIG. Although it was at the center position, it may be at the upper end or the lower end of the inner surface modified layer M2.

Next, another embodiment of the wafer processing system 1 will be described.

In the etching apparatus 60 of the above-described embodiment, the etchant E is supplied from above the separation surface W2a of the second separated wafer W2. You may also have a device. Such an etching device is provided, for example, stacked with the etching device 60 .

Further, although the cleaning apparatus 62 of the above embodiment cleans the separation surface W2a of the second separation wafer W2 from above, the wafer processing system 1 may further include a cleaning apparatus that cleans the separation surface W2a from below. good. Such a cleaning device is provided, for example, stacked with the cleaning device 62 .

FIG. 22 is an explanatory diagram of main steps of wafer processing performed in the wafer processing system 1. As shown in FIG. In this embodiment, steps A1 to A3 are performed to separate the wafer W to be processed, as shown in FIGS. In this embodiment, as will be described later, there is no need to turn over the second separated wafer W2, and step A4 is omitted. Along with this, the reversing device 61 may be omitted from the wafer processing system 1 .

Next, in step A5, the separated second separated wafer W2 is transferred to the cleaning apparatus. In the cleaning apparatus, as shown in FIG. 22(e), a scrubbing jig 200 such as a brush is brought into contact with the separation surface W2a from below while the second separation wafer W2 is rotationally held by a chuck (not shown). For example, pure water is supplied from the scrubbing jig 200 while contacting. Then, the separation surface W2a is cleaned.

Next, in step A6, the second separated wafer W2 is transferred to the etching apparatus. In this etching apparatus, as shown in FIG. 22(f), while rotating and holding the second separated wafer W2 on a chuck (not shown), from the nozzle 210 arranged below the second separated wafer W2, An etchant E is supplied to the central portion of the separation surface W2a. The etchant E etches the separation surface W2a.

In parallel with steps A5 and A6 being performed on the second separated wafer W2 as described above, step A7 is performed on the first separated wafer W1 as shown in FIGS. ˜A8 are performed, and the separation surface W1a is cleaned and etched.

This embodiment can also enjoy the same effect as the above embodiment. Moreover, the reversal of the front and back surfaces of the second separated wafer W2 in step A4 in the reversing device 61 can be omitted.

As shown in FIG. 23, the wafer processing system 1 according to another embodiment may further include a grinding device 220 as a grinding unit in the configuration of the above embodiments. In the above embodiment, the separation surface W2a (including the peripheral portion W2e) of the second separation wafer W2 is ground outside the wafer processing system 1, but in this embodiment, the separation surface W2a is ground by the grinding device 220. conduct. Further, in the following example, the case where the separation surface W1a of the first separation wafer W1 is also ground by the grinding device 220 will be described.

The grinding device 220 has a rotary table 230 , a first grinding unit 240 and a second grinding unit 250 .

The rotary table 230 is rotatable around a vertical center line 231 of rotation by a rotary mechanism (not shown). Four chucks 232 are provided on the rotary table 230 to suck and hold the separated wafers W1 and W2. The chucks 232 are evenly arranged on the same circumference as the rotary table 230, that is, arranged every 90 degrees. The four chucks 232 are movable to the transfer position A0 and the processing positions A1 and A2 by rotating the rotary table 230. As shown in FIG. The chuck 232 is rotatable by a rotating mechanism (not shown).

The delivery position A0 is a position on the wafer transfer area 40 side (X-axis negative direction side and Y-axis positive direction side) of the rotary table 230, and delivery of the separated wafers W1 and W2 is performed. The first machining position A1 is a position on the X-axis positive direction side and the Y-axis positive direction side of the rotary table 230, where the first grinding unit 240 is arranged. The second machining position A2 is a position on the X-axis negative direction side and the Y-axis negative direction side of the rotary table 230, where the second grinding unit 250 is arranged.

The first grinding unit 240 grinds the separation surface W1a of the first separation wafer W1. The first grinding unit 240 has a first grinding section 241 with an annular shaped rotatable grinding wheel (not shown). Also, the first grinding part 241 is configured to be movable in the vertical direction along the support 242 . Then, while the separation surface W1a of the first separation wafer W1 held by the chuck 232 is in contact with the grinding wheel, the chuck 232 and the grinding wheel are rotated to grind the separation surface W1a.

The second grinding unit 250 grinds the separation surface W2a of the second separation wafer W2. The second grinding unit 250 has a second grinding section 251 with an annular shaped rotatable grinding wheel (not shown). In addition, the second grinding section 251 is configured to be vertically movable along the support 252 . Then, while the separation surface W2a of the second separation wafer W2 held by the chuck 232 is in contact with the grinding wheel, the chuck 232 and the grinding wheel are rotated to grind the separation surface W2a.

24A and 24B are explanatory diagrams of main steps of wafer processing performed in the wafer processing system 1. FIG. FIG. 24 shows the processing of separated wafers W1 and W2 after steps A1 to A8 shown in FIGS. 8A to 8H of the above embodiment are performed. That is, FIGS. 24(a) to 24(c) show the processing performed on the second separation wafer W2 having the separation surface W2a etched as shown in FIG. 8(f). Also, FIGS. 24(d) to 24(f) show the processing performed on the first separation wafer W1 having the separation surface W1a etched as shown in FIG. 8(h).

First, the processing for the second separated wafer W2 will be described. In the wafer processing system 1, the second separated wafer W2 etched by the etching device 60 is transferred to the grinding device 220 by the wafer transfer device 42 as shown in FIG. In the grinding device 220, the second separated wafer W2 is transferred to the chuck 232 at the transfer position A0. After that, the rotary table 230 is rotated to move the second separated wafer W2 to the second processing position A2. Subsequently, as shown in FIG. 24A, the separation surface W2a is ground using the second grinding portion 251 to remove the peripheral edge portion W2e. After that, the rotary table 230 is rotated to move the second separated wafer W2 to the transfer position A0. At this time, the separation surface W2a may be cleaned with a cleaning liquid.

Next, the second separated wafer W2 is transferred to the cleaning device 62 by the wafer transfer device 42. As shown in FIG. In the cleaning device 62, the separation surface W2a of the second separation wafer W2 is scrub-cleaned using the scrub jig 140 as shown in FIG. 24(b). Then, particles on the separation surface W2a are removed.

Next, the second separated wafer W2 is transferred to the etching device 60 by the wafer transfer device 42. As shown in FIG. In the etching device 60, as shown in FIG. 24(c), the etchant E is supplied to the separation surface W2a from the nozzle 150 arranged above the second separation wafer W2, and the separation surface W2a is etched. Grinding traces remaining on the separation surface W2a are then removed.

As described above, in parallel with the processes shown in FIGS. 24A to 24C being performed on the second separated wafer W2, desired processes are performed on the first separated wafer W1. .

That is, the first separated wafer W1 etched by the etching device 60 is transferred to the grinding device 220 by the wafer transfer device 42 as shown in FIG. 8(h). In the grinding device 220, the first separated wafer W1 is transferred to the chuck 232 at the transfer position A0. After that, the rotary table 230 is rotated to move the first separated wafer W1 to the first processing position A1. Subsequently, as shown in FIG. 24D, the separation surface W1a is ground using the first grinding section 241 to thin the first separation wafer W1 to a desired thickness. After that, the rotary table 230 is rotated to move the first separated wafer W1 to the delivery position A0. At this time, the separation surface W1a may be cleaned with a cleaning liquid.

Next, the first separated wafer W1 is transferred to the cleaning device 62 by the wafer transfer device 42. As shown in FIG. In the cleaning device 62, the separation surface W1a of the first separation wafer W1 is scrub-cleaned using a scrub jig 140 as shown in FIG. 24(e). Then, particles on the separation surface W1a are removed.

Next, the first separated wafer W1 is transferred to the etching device 60 by the wafer transfer device 42. As shown in FIG. In the etching apparatus 60, as shown in FIG. 24(f), the etchant E is supplied to the separation surface W1a from the nozzle 150 arranged above the first separation wafer W1 to etch the separation surface W1a. Grinding traces remaining on the separation surface W1a are then removed.

When the second separated wafer W2 processed as described above is reused as a support wafer, it can be used as it is. On the other hand, when the second separated wafer W2 is reused as a product wafer, the separated surface W2a is polished outside the wafer processing system 1. FIG. Further, the first separated wafer W1 processed as described above has its separated surface W1a polished outside the wafer processing system 1. FIG.

This embodiment can also enjoy the same effect as the above embodiment. Moreover, since the wafer processing system 1 has the grinding device 220, grinding of the separation surfaces W1a and W2a can be performed, and the throughput of wafer processing can be further improved.

As in the above embodiment, when the first separation wafer W1 has been etched to a desired thickness in step A8, the grinding of the separation surface W1a shown in FIG. The cleaning of the separation surface W1a shown in 24(e) and the etching of the separation surface W1a shown in FIG. 24(f) may be omitted.

In the above embodiment, a plurality of annular inner surface modified layers M2 are formed in step A2, but the inner surface modified layers M2 may be formed spirally from the radially outer side to the inner side. Specifically, while rotating the chuck 100 (processing wafer W) and moving the laser head 110 in the Y-axis direction from the radially outer side to the inner side of the processing wafer W, the inside of the processing wafer W from the laser head 110 is moved. is irradiated with laser light L2.

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

Further, in the above embodiment, the case of thinning the processing wafer W in the superimposed wafer T has been described, but the above embodiment can also be applied to the case of thinning one wafer. For example, one wafer may be thinned and then bonded to the support wafer S to form the superimposed wafer T. FIG.

Further, in the above embodiment, the case where the processing wafer W as the processing object is a silicon wafer has been described as an example, but the type of the processing object is not limited to this. For example, instead of a silicon wafer, a glass substrate, a SiC substrate, a sapphire substrate, a single crystal substrate, a polycrystalline substrate, an amorphous substrate, or the like may be selected as the object to be processed. Also, for example, an ingot, a base, a thin plate, or the like may be selected instead of the substrate as the object to be processed.

Further, in the above embodiment, the case where the shape of the processing wafer W is circular has been described as an example, but the shape of the processing wafer W is not limited to this. can take any shape.

Furthermore, the technique according to the content of the present disclosure can be applied when manufacturing a processing wafer W including a device region having a plurality of devices formed on the surface thereof and an outer peripheral marginal region surrounding the device region. can.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The embodiments described above may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

Reference Signs List 1 wafer processing system 64 modification device 70 control device 110 laser head M1 peripheral modified layer M2 internal surface modified layer L1, L2 laser light W processed wafer

Claims (18)

A processing apparatus for processing a processing wafer, which is an object to be processed,
a chuck holding a superimposed wafer having the process wafer and the support wafer bonded together;
A peripheral edge modified layer is formed inside the process wafer by irradiating a peripheral edge laser beam along the boundary between the peripheral edge portion and the central portion of the process wafer, and along the surface direction of the process wafer . a modified portion that forms an internal surface modified layer by irradiating a laser beam;
a separating unit that separates the processing wafer into a first separated wafer and a second separated wafer using the peripheral edge modified layer and the inner surface modified layer as base points, and separates the second separated wafer from the supporting wafer; When,
a control unit that controls the reforming unit and the separation unit ;
The control unit adjusts the position of the upper end of the inner surface modified layer to the same height or higher than the position of the uppermost end of the peripheral edge modified layer in a height direction perpendicular to the surface direction of the wafer to be processed . , a processing device for controlling the reformer. 2. The processing apparatus according to claim 1, wherein said control section controls said separation section so that said peripheral portion remains on said second separated wafer separated from said support wafer. 3. The processing apparatus according to claim 1, wherein an unbonded region is formed radially outside a bonding region where the processing wafer and the support wafer are bonded at the interface between the processing wafer and the support wafer. The process according to any one of claims 1 to 3 , wherein the control unit controls the modifying unit so that the inner surface modified layer is formed radially inward of the peripheral modified layer. Device. 4. The control unit according to any one of claims 1 to 3 , wherein the control unit controls the modifying unit such that the outermost inner surface modified layer is formed above the peripheral modified layer. processing equipment. The controller controls that, in a height direction perpendicular to the surface direction of the wafer to be processed , the position of the upper end of the inner surface modified layer is the same as the position of the apex of the crack extending upward from the uppermost end of the peripheral edge modified layer. 6. The processing apparatus according to any one of claims 1 to 5 , wherein said reforming section is controlled to have a height or height. The processing apparatus according to any one of claims 1 to 6 , wherein the control section controls the modifying section so as to form the inner surface modified layer after forming the peripheral edge modified layer. . a cleaning unit that cleans the separation surface of the first separation wafer or the separation surface of the second separation wafer ;
The processing apparatus according to any one of claims 1 to 7 , further comprising an etching section for etching the separation surface of the first separation wafer or the separation surface of the second separation wafer . a reversing unit for reversing the front and back surfaces of the second separation wafer ;
The cleaning unit cleans the separation surface of the second separation wafer from above,
9. The processing apparatus according to claim 8 , wherein said etching unit supplies an etchant from above to the separation surface of said second separation wafer . A processing method for processing a processing wafer, which is an object to be processed,
holding, with a chuck, a superposed wafer in which the process wafer and the support wafer are bonded together;
forming a modified peripheral edge layer by irradiating a peripheral edge laser beam from a modifying section into the inside of the processed wafer along a boundary between a peripheral edge portion and a central portion of the processed wafer;
forming an internal surface modified layer by irradiating an internal surface laser beam along the surface direction of the wafer to be processed ;
separating the processing wafer into a first separated wafer and a second separated wafer using the peripheral edge modified layer and the inner surface modified layer as base points, and separating the second separated wafer from the support wafer; , has
In the height direction orthogonal to the surface direction of the wafer to be processed , the edge modification is performed such that the upper end of the inner surface modified layer is at the same height or higher than the uppermost edge of the edge modified layer. A processing method for forming a layer and said internal surface modification layer. 11. The processing method of claim 10, wherein the peripheral edge remains on the second separated wafer separated from the support wafer. 12. The processing method according to claim 10, wherein an unbonded region is formed radially outside a bonding region where the processing wafer and the support wafer are bonded at the interface between the processing wafer and the support wafer. 13. The modified peripheral layer and the modified inner surface layer are formed so that the modified inner surface layer is formed radially inward of the modified peripheral layer, according to any one of claims 10 to 12 Described processing method. 13. The modified peripheral layer and the modified inner surface layer are formed such that the outermost inner surface modified layer is formed above the modified peripheral layer. The treatment method described in . In the height direction orthogonal to the surface direction of the processing wafer , the position of the upper end of the inner surface modified layer is the same height or higher than the position of the apex of the crack extending upward from the uppermost end of the peripheral edge modified layer. The processing method according to any one of claims 10 to 14 , wherein the peripheral edge modified layer and the inner surface modified layer are formed in such a manner. The processing method according to any one of claims 10 to 15 , wherein the inner surface modified layer is formed after forming the peripheral edge modified layer. cleaning the separation surface of the first separation wafer or the separation surface of the second separation wafer ;
etching the separation surface of the first separation wafer or the separation surface of the second separation wafer . flipping the front and back surfaces of the second separation wafer ;
cleaning the separation surface of the second separation wafer from above during the cleaning;
18. The processing method according to claim 17 , wherein during said etching, an etchant is supplied from above to the separation surface of said second separation wafer .

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