JP2023121926A - Treatment method and treatment system - Google Patents

Abstract

To appropriately remove a peripheral edge part of a first substrate, in a polymerization substrate where the first substrate and a second substrate are joined.SOLUTION: A treatment method of a polymerization substrate where a first substrate and a second substrate are joined includes: forming at least a first film and a second film, on an interface between the first substrate and the second substrate in a peripheral edge part of the first substrate that is a removal object, and forming a first non-joint region where the joint force is lowered in the first film on the interface between the first substrate and the second substrate; forming a second non-joint region where the joint force is lowered on the interface between the second film and the first substrate in the first substrate; forming a peripheral edge modified layer as a base point of peeling of the peripheral edge part, along a boundary between the peripheral edge part of the first substrate and a central part of the first substrate; and removing the peripheral edge part from the polymerization substrate with the peripheral edge modified layer as a base point.SELECTED DRAWING: Figure 8

Description

The present disclosure relates to processing methods and processing systems.

In Patent Document 1, in a superimposed substrate in which a first substrate and a second substrate are bonded, a reforming agent is introduced into the inside of the first substrate along the boundary between the peripheral edge portion and the central portion of the first substrate to be removed. A substrate processing system is disclosed that includes a modified layer forming device for forming a layer and a peripheral edge removing device for removing a peripheral edge portion of a first substrate with the modified layer as a starting point.

WO2019/176589

The technique according to the present disclosure appropriately removes the peripheral edge portion of the first substrate in the superimposed substrate in which the first substrate and the second substrate are bonded.

One aspect of the present disclosure is a method for processing a superimposed substrate in which a first substrate and a second substrate are bonded, wherein the first substrate and the second substrate are removed at a peripheral edge portion of the first substrate to be removed. At least a first film and a second film are formed at the interface between the substrates of the first substrate, and the bonding strength of the first film at the interface between the first substrate and the second substrate is reduced. forming a bonded region; forming a second unbonded region with reduced bonding strength at an interface between the second film of the first substrate and the first substrate; and the first substrate. and a center portion of the first substrate, forming a modified peripheral edge layer that serves as a starting point for peeling of the peripheral edge portion; from the polymerized substrate.

According to the present disclosure, it is possible to appropriately remove the peripheral portion of the first substrate in the superimposed substrate in which the first substrate and the second substrate are bonded.

It is a side view which shows the structural example of the superposition|polymerization wafer concerning embodiment. FIG. 2 is an explanatory diagram showing a cross section of a peripheral portion of the superimposed wafer shown in FIG. 1; 1 is a plan view showing an outline of the configuration of a wafer processing system according to this embodiment; FIG. FIG. 3 is a plan view showing the outline of the configuration of an interfacial reforming device and an internal reforming device; FIG. 2 is a side view showing the schematic configuration of an interfacial reforming device and an internal reforming device; FIG. 4 is an explanatory diagram showing how a first unbonded region is formed on a superposed wafer; FIG. 4 is an explanatory view showing a first unbonded region formed on a superposed wafer; FIG. 10 is an explanatory diagram showing how a second unbonded region is formed on the superposed wafer; FIG. 10 is an explanatory diagram showing a second unbonded region formed on the superposed wafer; FIG. 4 is an explanatory diagram showing how a modified layer is formed on a polymerized wafer; FIG. 4 is an explanatory diagram showing a modified layer formed on a polymerized wafer; FIG. 10 is an explanatory diagram showing how an edge trim is formed on a superimposed wafer;

In the manufacturing process of semiconductor devices, a first substrate (silicon substrate such as a semiconductor) having a device layer including a plurality of electronic circuits and a bonding film (for example, an oxide film) formed on the surface thereof and a second substrate are bonded. In some cases, a so-called edge trim is performed to remove the peripheral edge of the first substrate in the superimposed substrate.

Edge trimming of the first substrate is performed using, for example, the substrate processing system disclosed in US Pat. That is, a modified layer is formed by irradiating the inside of the first substrate with an internal laser beam, and the peripheral portion is removed from the first substrate using the modified layer as a starting point. Further, according to the substrate processing system described in Patent Document 1, a modified surface is formed by irradiating an interface laser beam onto an oxide film formed at the interface between a first substrate and a second substrate. It is intended to reduce the bonding strength between the first substrate and the second substrate at the peripheral edge portion to appropriately remove the peripheral edge portion.

By the way, at the interface between the first substrate and the second substrate in the peripheral edge portion to be removed, various factors such as the result of the substrate processing in the previous step and the conditions for bonding the first substrate and the second substrate are present. Depending on factors, the device layer and the bonding film (oxide film) may coexist. In other words, although the device layer and the bonding film are formed on the surface of the first substrate as described above, the bonding portion with the device layer and the bonding film are formed on the surface of the first substrate in the peripheral portion to be removed. , and the bonding portion with the bonding film may be mixed.

As disclosed in Patent Document 1, an oxide film formed at the interface between the first substrate and the second substrate is irradiated with an interface laser beam when forming the modified surface. If the device layer and the bonding film coexist in the irradiation range of the interface laser light, the modified surface may not be properly formed, and the peripheral portion of the first substrate may not be properly removed.

The technique according to the present disclosure has been made in view of the above circumstances, and appropriately removes the peripheral portion of the first substrate in the superimposed substrate in which the first substrate and the second substrate are bonded. 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 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.

In the wafer processing system 1 according to the present embodiment, which will be described later, a superposed wafer T in which a first wafer W and a second wafer S are bonded as shown in FIG. 1 is processed. A wafer is an example of a substrate. Hereinafter, the surface of the first wafer W to be bonded to the second wafer S will be referred to as a front surface Wa, and the surface opposite to the front surface Wa will be referred to as a rear surface Wb. Similarly, in the second wafer S, the surface on the side bonded to the first wafer W is referred to as a front surface Sa, and the surface opposite to the front surface Sa is referred to as a rear surface Sb.

The first wafer W is, for example, a semiconductor wafer such as a silicon substrate, and a device layer Dw including a plurality of devices is formed on the surface Wa side. A bonding film Fw is further formed on the device layer Dw, and is bonded to the second wafer S via the bonding film Fw. As the bonding film Fw, for example, an oxide film (THOX film, SiO ₂ film, TEOS film), SiC film, SiCN film, adhesive, or the like is used. The peripheral edge portion We of the first 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 described later, and is in the range of 0.5 mm to 3 mm in the radial direction from the outer end portion of the first wafer W, for example. In the following description, a region radially inside the peripheral edge portion We to be removed in the first wafer W may be referred to as a central portion Wc.

The second wafer S has, for example, the same configuration as the first wafer W, the device layer Ds and the bonding film Fs are formed on the surface Sa, and the peripheral portion is chamfered. The second wafer S does not have to be a device wafer on which the device layer Ds is formed, and may be a supporting wafer that supports the first wafer W, for example. In such a case, the second wafer S functions as a protective material that protects the device layer Dw of the first wafer W. FIG.

The superimposed wafer T to be processed is configured as described above. That is, the bonding films Fw and Fs and the device layers Dw and Ds are formed at the interface between the first wafer W and the second wafer S (between the surface Wa and the surface Sa which are surfaces to be bonded). It is In other words, the surface Wa of the first wafer W and the surface Wa of the second wafer S are located at the "interface between the first wafer W and the second wafer S" irradiated with laser light in the edge trim described later. Sa, bonding films Fw and Fs, and device layers Dw and Ds are included.

As shown in FIG. 2, a device layer Dw and a bonding film are present at the interface between the first wafer W and the second wafer S at the edge portion We to be removed, which is irradiated with laser light in edge trimming described later. Fw may be mixed. More specifically, the device layer Dw formed on the surface of the first wafer W may deviate from the formation range to the peripheral edge portion We to be removed due to various factors.
In the wafer processing system 1 according to the present embodiment, even if the formation range of the device layer Dw deviates from the peripheral edge portion We to be removed as described above, the peripheral edge portion We is appropriately removed from the overlapped wafer T. .

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

The loading/unloading station 2 is provided with a cassette mounting table 10 on which a cassette C capable of accommodating a plurality of superposed wafers T is mounted. A wafer transfer device 20 is provided adjacent to the cassette mounting table 10 on the positive side of the cassette mounting table 10 in the X-axis direction. The wafer transfer device 20 is configured to move on a transfer path 21 extending in the Y-axis direction and transfer superimposed wafers T between a cassette C on the cassette mounting table 10 and a transition device 30 which will be described later.

The loading/unloading station 2 is provided with a transition device 30 adjacent to the wafer transport device 20 on the X-axis positive direction side of the wafer transport device 20 and for transferring the overlapped wafers T to and from the processing station 3 . ing.

The processing station 3 is provided with a wafer transfer device 40 , an interface reforming device 50 , an internal reforming device 60 , a peripheral removal device 70 and a cleaning device 80 .

The wafer transfer device 40 is provided on the positive side of the transition device 30 in the X-axis direction. The wafer transfer device 40 is configured to be movable on a transfer path 41 extending in the X-axis direction, and includes the transition device 30, the interface reforming device 50, the internal reforming device 60, the edge removing device 70, and the cleaning device of the loading/unloading station 2. The device 80 is configured so that the superposed wafer T can be transferred.

The interface reforming device 50 as a first laser irradiation unit irradiates the interface between the first wafer W and the second wafer S with the interface laser light L1 (see FIG. 6) in pulses, A first unbonded area Ae1 in which the bonding strength between the wafer W and the second wafer S is reduced is formed. As the interface laser light L1, for example, laser light having a wavelength that is absorbed by the bonding film Fw formed at the interface between the first wafer W and the second wafer S and reflected by the device layer Dw, such as CO ₂ A laser beam having an infrared wavelength, such as a laser, is selected.

As shown in FIGS. 4 and 5, the interface modification device 50 has a chuck 100 that holds the superposed wafer T on its upper surface. The chuck 100 sucks and holds the rear surface Sb of the second wafer S with the first wafer W on the upper side and the second 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 on a rail 106 extending in the Y-axis direction on a base 105 via a moving mechanism 104 provided on the underside thereof. Although the driving source of the moving mechanism 104 is not particularly limited, for example, a linear motor is used.

A laser irradiation unit 110 is provided above the chuck 100 . The laser irradiation unit 110 has a laser head 111 and a lens 112 . The lens 112 is a cylindrical member provided on the lower surface of the laser head 111, and is configured to cover the inside of the superposed wafer T held by the chuck 100, more specifically, the interface between the first wafer W and the second wafer S. is irradiated with the interface laser beam L1. As a result, the portion irradiated with the interfacial laser beam L1 inside the superposed wafer T is modified, and a first unbonded area Ae1 in which the bonding strength between the first wafer W and the second wafer S is reduced is formed. do. The first unbonded region Ae1 is formed at the interface corresponding to the region where the bonding film Fw is formed on the surface Wa of the first wafer W in one example.

The laser head 111 is supported by a support member 113 . The laser head 111 is configured to be vertically movable by a lifting mechanism 115 along a rail 114 extending in the vertical direction. Also, the laser head 111 is configured to be movable in the Y-axis direction by a moving mechanism 116 . Note that the lifting mechanism 115 and the moving mechanism 116 are each supported by a support column 117 .

An imaging mechanism 120 is provided above the chuck 100 and on the positive Y-axis side of the laser head 111 . The imaging mechanism 120 includes one or more cameras 121 selected from, for example, a macro camera, a micro camera, or the like, and images the outer edge of the superposed wafer T held by the chuck 100 . The imaging mechanism 130 includes, for example, a coaxial lens, irradiates infrared light (IR), and receives reflected light from an object. Note that the imaging mechanism 120 may be configured to be vertically movable by the lifting mechanism 122 and further movable in the Y-axis direction by the moving mechanism 123 .

In the illustrated example, the chuck 100 can be rotated and horizontally moved relative to the laser head 111 by the rotating mechanism 103 and the moving mechanism 104. It may be constructed so as to be physically rotatable and horizontally movable. Also, both the chuck 100 and the laser head 111 may be configured to be relatively rotatable and horizontally movable.

An internal reforming device 60 as a second laser irradiation unit has, in one example, the same configuration as the interfacial reforming device 50 . That is, the internal reforming device 60 includes a chuck 200 that holds a superimposed wafer T on its upper surface, a laser irradiation unit 210 that irradiates internal laser light toward the superposed wafer T held by the chuck 200 , and a superposed wafer on the chuck 200 . An imaging mechanism 220 for imaging T is provided.

The chuck 200 is rotatable about a vertical axis by a rotating mechanism 203 and horizontally movable by a moving mechanism 204 .
The laser irradiation unit 210 has a laser head 211 and a lens 212 . The laser irradiation unit 210 is configured to be vertically movable by a lifting mechanism 215 and movable in the Y-axis direction by a moving mechanism 216 .
The imaging mechanism 220 includes a camera 221 for imaging the outer edge of the superposed wafer T held by the chuck 200 , an elevating mechanism 222 and a moving mechanism 223 .

The chuck 200 and the laser irradiation unit 210 may be configured to be relatively rotatable and horizontally movable by the rotating mechanism 203 and the moving mechanism 204, or the laser irradiation unit 210 may be arranged relative to the chuck 200. It may be constructed so as to be physically rotatable and horizontally movable. Also, both the chuck 200 and the laser irradiation unit 210 may be configured to be relatively rotatable and horizontally movable.

In the internal reforming apparatus 60 according to the technology of the present disclosure, the laser irradiation unit 210 irradiates the inside of the first wafer W with the second internal laser beam L3 (see FIG. 10) in a pulsed manner so that the peripheral edge portion A modified peripheral layer M1 serving as a starting point for peeling of We and a divided modified layer M2 serving as a starting point for dividing the peripheral edge portion We into small pieces are formed. As the second internal laser beam L3, for example, a laser beam having a wavelength at which multiphoton absorption occurs in the first wafer W, for example, a laser beam having a near-infrared wavelength such as a fiber laser or a YAG laser is selected. be done.

Further, in the present embodiment, the laser irradiation unit 210 irradiates the interface between the first wafer W and the second wafer S with the similar first internal laser beam L2 (see FIG. 8), and the first wafer A second unbonded area Ae2 in which the bonding strength between W and the second wafer S is lowered is formed. The second unbonded region Ae2 is formed at the interface corresponding to the region where the device layer Dw is formed on the surface Wa of the first wafer W in one example. As the first internal laser beam L2, for example, a laser beam having a wavelength that passes through the bonding film Fw formed at the interface between the first wafer W and the second wafer S and is absorbed by the device layer Dw. For example, a laser beam having a near-infrared wavelength such as a fiber laser or a YAG laser is selected.

In the internal modifying device 60, the second internal laser beam L3 for forming the peripheral modified layer M1 and the divided modified layer M2 and the first internal laser beam L3 for forming the second unbonded region Ae2 The same laser beam may be used as the laser beam L2, or different laser beams may be used. That is, the laser irradiation unit 210 includes at least one or more light sources for irradiating the first internal laser beam L2 and the second internal laser beam L3.

The peripheral edge removing device 70 removes the peripheral edge portion We of the first wafer W, that is, performs edge trimming, with the modified peripheral edge layer M1 formed by the internal modifying device 60 as a base point. Any method of edge trimming can be selected. In one example, the rim remover 70 may insert a blade that is, for example, wedge-shaped. Further, for example, an air blow or a water jet may be injected toward the peripheral edge portion We to apply an impact to the peripheral edge portion We.

The cleaning device 80 cleans the first wafer W and the second wafer S after edge trimming by the edge removing device 70 to remove particles on these wafers. Any washing method can be selected.

A controller 90 is provided in the wafer processing system 1 described above. The control device 90 is, for example, a computer and has a program storage unit (not shown). The program storage unit stores programs for controlling the processing of the superposed wafers T in the wafer processing system 1 . The program storage unit also stores a program for controlling the operation of drive systems such as the various processing devices and transfer devices described above to realize wafer processing, which will be described later, in the wafer processing system 1 . The program may be recorded in a computer-readable storage medium H and installed in the control device 90 from the storage medium H. Further, the storage medium H may be temporary or non-temporary.

Next, wafer processing performed using the wafer processing system 1 configured as described above will be described. In addition, in this embodiment, the first wafer W and the second wafer S are joined to form a superimposed wafer T in advance.

First, a cassette C containing a plurality of superposed wafers T is mounted on the cassette mounting table 10 of the loading/unloading station 2 . Next, the wafer transfer device 20 takes out the superposed wafer T from the cassette C and transfers it to the interface modification device 50 via the transition device 30 and the wafer transfer device 40 .

In the interface modification device 50, first, the superposed wafer T held by the chuck 100 is moved to the first imaging position. The first imaging position is a position where the imaging mechanism 120 can image the outer edge of the first wafer W. FIG. At the first imaging position, the imaging mechanism 120 captures an image of the outer edge of the first wafer W in 360 degrees in the circumferential direction while rotating the chuck 100 . The captured image is output from the imaging mechanism 120 to the control device 90 .

The controller 90 calculates the amount of eccentricity between the center of the chuck 100 and the center of the first wafer W from the image of the imaging mechanism 120 . Further, the controller 90 calculates the amount of movement of the chuck 100 based on the calculated amount of eccentricity so as to correct the Y-axis component of the amount of eccentricity. The controller 90 horizontally moves the chuck 100 along the Y-axis direction based on the calculated movement amount to correct the eccentricity between the center of the chuck 100 and the center of the first wafer W. FIG.

Further, the control device 90 sets the irradiation area of the interface laser light L1 for forming the unbonded area Ae based on the position of the outer edge of the first wafer W specified from the image of the imaging mechanism 120. . The irradiation area of the interface laser beam L1 is set as an annular area having a desired radial width from the outer edge of the first wafer W, for example. The radial width of the irradiation region of the interface laser beam L1 is set to a width that can appropriately remove the peripheral edge portion We of the first wafer W to be removed.

After the eccentricity of the chuck 100 and the first wafer W is corrected and the irradiation area of the interface laser beam L1 is set, the chuck 100 and the laser irradiation unit 110 are relatively rotated, and are rotated in the Y-axis direction. While relatively moving along, the interface between the first wafer W and the second wafer S corresponding to the set irradiation area (in the example of FIG. 6, the first wafer W and the bonding film Fw or the device layer Dw interface) is irradiated with an interface laser beam L1 in a pulsed manner.
Here, the interface laser beam L1 is a laser beam having a wavelength that is absorbed by the bonding film Fw and reflected by the device layer Dw as described above, for example, a laser beam having an infrared wavelength such as a CO ₂ laser. Therefore, as shown in FIG. 6, the interface laser beam L1 is applied to the bonding film Fw (oxide film) and the device layer Dw (see FIG. 2) mixed at the interface of the peripheral portion We. While the light is absorbed by the device layer Dw, it is reflected without being absorbed by the device layer Dw.

As a result, in the interface modification apparatus 50, as shown in FIGS. 6 and 7, at the interface of the peripheral portion We, the region corresponding to the interface between the first wafer W and the bonding film Fw is modified. A first unbonded region Ae1 in which the bonding strength between W and the second wafer S is reduced is formed. In the first unbonded region Ae1, for example, the irradiated interface laser beam L1 is absorbed by the bonding film Fw, which causes the temperature of the bonding film Fw to rise. It is formed by peeling occurring at the interface of the bonding film Fw.
On the other hand, as shown in FIGS. 6 and 7, in the interface of the peripheral portion We, the interface laser light L1 is reflected in the region corresponding to the interface between the first wafer W and the device layer Dw, and the first unbonded Area Ae1 is not formed.

In the embodiment, "improvement of the interface" includes making the bonding film and the device layer amorphous at the irradiation position of the interface laser beam L1 (or the first internal laser beam L2 described later), This includes peeling of the wafer W from the bonding film and the device layer, and the like. In other words, in the "non-bonded region" in the embodiment, it is sufficient that the bonding strength between at least the first wafer W and the second wafer S is lowered. It includes the deterioration of the bonding strength due to the amorphization of the bonding layer and the weakening of the bonding strength due to the peeling of the bonding film or the like.

The superposed wafer T in which the first unbonded region Ae1 is formed at the interface between the first wafer W and the second wafer S is then transferred to the internal reforming device 60 by the wafer transfer device 40 .

In the internal reforming device 60, first, the superposed wafer T held by the chuck 200 is moved to the second imaging position. The second imaging position is a position where the imaging mechanism 220 can image the outer edge of the first wafer W. FIG. At the second imaging position, the imaging mechanism 220 captures an image of the outer edge of the first wafer W in the circumferential direction of 360 degrees while rotating the chuck 200 . The captured image is output from the imaging mechanism 220 to the control device 90 .

The controller 90 calculates the amount of eccentricity between the center of the chuck 200 and the center of the first wafer W from the image of the imaging mechanism 220 . Further, the controller 90 calculates the amount of movement of the chuck 200 based on the calculated amount of eccentricity so as to correct the Y-axis component of the amount of eccentricity. The controller 90 horizontally moves the chuck 200 along the Y-axis direction based on the calculated movement amount, and corrects the eccentricity between the center of the chuck 200 and the center of the first wafer W. FIG.

Further, in the control device 90, based on the position of the outer edge of the first wafer W specified from the image of the imaging mechanism 220, the irradiation area of the first internal laser beam L2 for forming the unbonded area Ae. set. The irradiation area of the first internal laser beam L2 is the same range as the formation area of the unbonded area Ae set in the interface modification device 50, that is, the desired radial width from the outer edge of the first wafer W. is set in an annular region with

After the eccentricity of the chuck 200 and the first wafer W is corrected and the irradiation area of the first internal laser beam L2 is set, next, the chuck 200 and the laser irradiation unit 210 are relatively rotated, and the Y While relatively moving along the axial direction, the first wafer W is applied to the interface between the first wafer W and the second wafer S in the set irradiation area (the inside of the bonding film Fw and the device layer Dw in the example of FIG. 8). is irradiated with the internal laser light L2 in a pulsed manner.
Here, the first internal laser beam L2 is a laser beam having a wavelength that is transmitted through the bonding film Fw and absorbed by the device layer Dw as described above, for example, a laser beam having a near-infrared wavelength such as a YAG laser. Light. The first internal laser beam L2 having a near-infrared wavelength has a higher energy density than the interface laser beam L1 having an infrared wavelength. Therefore, the first internal laser beam L2 has an absorptive property with respect to the device layer Dw that could not be modified by the interface laser beam L1.

As a result, in the internal reforming apparatus 60, as shown in FIGS. 8 and 9, the region corresponding to the interface between the first wafer W and the device layer Dw at the interface of the peripheral portion We is reformed. and a second unbonded area Ae2 in which the bonding strength of the second wafer S is reduced. In other words, in the internal reforming device 60, prior to the formation of the peripheral modified layer M1, which will be described later, the second unbonded region Ae1 is formed on the interface where the interface modifying device 50 cannot form the first unbonded region Ae1. A joining region Ae2 is formed. In one example, the second unbonded region Ae2 is destroyed by ablation of the device layer Dw by irradiating the first inner laser beam L2 focused on the inside of the device layer Dw. It is formed by peeling occurring at the interface between the wafer W of 1 and the device layer Dw.
On the other hand, as shown in FIGS. 8 and 9, in the interface of the peripheral portion We, the first internal laser beam L2 is transmitted through a region corresponding to the interface between the first wafer W and the bonding film Fw. 2 unbonded area Ae2 is not formed.

The inside of the first wafer W is irradiated with the first internal laser beam L2 to form a peripheral modified layer M1, which will be described later. In other words, in addition to the device layer Dw, multiphoton absorption is generated in the first wafer W (silicon).
Therefore, in the internal reforming apparatus 60, as shown in FIG. It is set at a position where multiphoton absorption does not occur.

As described above, in the wafer processing system 1 according to the present embodiment, the interface laser light L1 in the interface modification device 50 is applied to the interface between the first wafer W and the second wafer S corresponding to the peripheral portion We. and the first internal laser beam L2 in the internal reforming device 60, respectively. As a result, even when the bonding film Fw and the device layer Dw coexist at the interface of the peripheral portion We as shown in FIG. can form an unbonded area Ae1 and a second unbonded area Ae2).
In edge trimming, which will be described later, the peripheral portion We of the first wafer W to be removed is removed. The existence of the edge portion We can be appropriately removed.

When the second unbonded region Ae2 is formed at the interface between the first wafer W and the second wafer S, the second internal laser beam L3 is directed to the focal point position ( The second internal laser beam L3 irradiation position) is set inside the first wafer W (silicon). Then, a predetermined irradiation position inside the first wafer W is irradiated with the second internal laser beam L3 in a pulsed manner, and as shown in FIGS. and a divided modified layer M2 are sequentially formed. The modified peripheral layer M1 serves as a base point for removing the peripheral edge portion We in edge trimming, which will be described later. The divided modified layer M2 serves as a starting point for dividing the peripheral portion We to be removed into small pieces.
In one example, the formation position of the modified peripheral layer M1 is determined slightly radially inward of the radially inner end portion of the unjoined region Ae.

In the illustrated example, the second inner laser beam L3 for forming the peripheral edge modified layer M1 and the split modified layer M2 and the first inner laser beam L3 for forming the second unjoined region Ae2 are used. Although different laser beams are used as the internal laser beam L2, as described above, the first internal laser beam L2 and the second internal laser beam L3 may be the same. In this case, the laser irradiation unit for irradiating the first internal laser beam L2 and the laser irradiation unit for irradiating the second internal laser beam L3 may be the same, or each laser irradiation unit may It may be arranged independently. Similarly, the light source for the first internal laser beam L2 and the light source for the second internal laser beam L3 may be the same, or the respective light sources may be arranged independently. Further, when the same light source and laser irradiation unit are used in this manner, the irradiation conditions of the internal laser light used in each step may be changed as appropriate.

That is, when the same laser beam is used as the first internal laser beam L2 and the second internal laser beam L3, the internal laser beam L3 is applied to the first wafer W (silicon) when the second unbonded region Ae2 is formed. Various irradiation conditions such as the focal point position of the internal laser beam and the energy density may be optimized so that multiphoton absorption of the laser beam does not occur. Similarly, various irradiation conditions such as energy density may be optimized so that the device layer Dw is not ablated by the internal laser beam when forming the peripheral edge modified layer M1 and the divided modified layer M2. .

Next, the superposed wafer T in which the modified edge layer M1 and the divided modified layer M2 are formed inside the first wafer W is transferred to the edge removing apparatus 70 by the wafer transfer apparatus 40 .

As shown in FIG. 12, the peripheral edge removing device 70 removes the peripheral edge portion We of the first wafer W, that is, performs edge trimming. At this time, the peripheral edge portion We is peeled off from the central portion of the first wafer W (inward in the radial direction of the peripheral edge portion We) with the modified peripheral layer M1 as a base point, and the unbonded area Ae (first unbonded area It is completely separated from the second wafer S with Ae1 and the second unbonded area Ae2) as base points. At this time, the peripheral portion We to be removed is divided into small pieces with the divided modified layer M2 as a base point.

In removing the peripheral portion We, for example, a wedge-shaped blade B (see FIG. 12) may be inserted into the interface between the first wafer W and the second wafer S forming the overlapped wafer T. FIG.

The superposed wafer T from which the peripheral portion We of the first wafer W has been removed is then transferred to the cleaning device 80 by the wafer transfer device 40 . The cleaning device 80 cleans the first wafer W and/or the second wafer S from which the peripheral portion We has been removed.

After that, the superposed wafer T that has undergone all the processes is transferred to the transition device 30 by the wafer transfer device 40 and transferred to the cassette C on the cassette mounting table 10 by the wafer transfer device 20 . Thus, a series of wafer processing in the wafer processing system 1 is completed.

In the above description, after forming the first unbonded region Ae1 in the interface modification device 50, the internal modification device 60 forms the second unbonded region Ae2, the peripheral edge modified layer M1, and the split modified layer M2. However, the order of wafer processing in the wafer processing system 1 is not limited to this. That is, after the second unbonded area Ae2, the peripheral edge modified layer M1 and the divided modified layer M2 are formed by the internal modifying device 60, the first unbonded area Ae1 is formed by the interface modifying device 50. may

According to the edge trimming method according to the present embodiment, even when the bonding film Fw and the device layer Dw are mixed at the interface between the first wafer W and the second wafer S, the peripheral edge portion to be removed At least one of the first unbonded area Ae1 and the second unbonded area Ae2 in which the bonding strength between the first wafer W and the second wafer S is reduced is formed on the entire surface of We. That is, the first unbonded region Ae1 or the second unbonded region Ae2 reduces at least the bonding strength between the first wafer W and the second wafer S over the entire surface of the peripheral edge We. is properly removed from the second wafer S.

In the above embodiment, the irradiation area of the first interior laser beam L2 for forming the second unbonded area Ae2 is replaced by the interface laser beam L1 for forming the first unbonded area Ae1. It was set to the same range as the irradiation area. In other words, the interface laser beam L1 and the first internal laser beam L2 are applied to the entire surface of the annular region (peripheral edge portion We to be removed) having a desired radial width from the outer end portion of the first wafer W. were both irradiated.
However, the method for determining the irradiation regions of the interface laser beam L1 and the first internal laser beam L2 is not limited to this. For example, when the formation range of the bonding film Fw and the device layer Dw can be detected in the peripheral portion We, or when the formation range of the bonding film Fw and the device layer Dw is known in advance, the formation region of the bonding film Fw The interface laser beam L1 may be selectively applied to the region where the device layer Dw is formed, and the first internal laser beam L2 may be applied to the formation region of the device layer Dw. In this case, the irradiation area of the interface laser beam L1 and the first internal laser beam L2 is reduced as compared with the above embodiment, so that the energy consumption for forming the unbonded area Ae can be reduced.

In the above embodiment, the interface modification device 50 forms the first unbonded region Ae1, and the internal modification device 60 forms the second unbonded region Ae2, the peripheral modified layer M1, and the split modified layer M2. formed. However, the apparatus for forming the first unbonded area Ae1, the second unbonded area Ae2, the peripheral modified layer M1, and the split modified layer M2 is not limited to this.
For example, instead of forming the second unbonded area Ae2 with the internal modification device 60, the interface modification device 50 may further form the second unbonded region Ae2. In this case, the laser irradiation unit 110 of the interface modification device 50 may be configured to arbitrarily switch irradiation between the interface laser beam L1 and the first internal laser beam L2, or the interface laser beam L1 and a laser irradiation unit for applying the first internal laser beam L2 may be arranged independently.
Further, for example, instead of forming the second unbonded area Ae2 with the internal modification apparatus 60, a second interface modification apparatus (not shown) for forming the second unbonded area Ae2 is used for wafer processing. It may be arranged independently in the system 1. In this case, the interface modification device 50 for forming the first unbonded region Ae1 corresponds to the "first interface modification section" (not shown) according to the technique of the present disclosure.

In the above-described embodiment, two types of films (the bonding film Fw and the device layer Dw) are mixed at the interface of the peripheral portion We, and two types of laser beams (the interface laser beam L1 and the first The case of irradiating the interface with the internal laser beam L2) has been described as an example. However, for example, when two or more types of films coexist at the interface of the peripheral portion We, the interface may be irradiated with two or more types of laser beams.

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.

1 Wafer Processing System 50 Interface Modification Device 60 Internal Modification Device 70 Edge Removal Device Ae1 First Unbonded Area Ae2 Second Unbonded Area L1 Interface Laser Light L2 First Internal Laser Light M1 Periphery Modified Layer S second wafer T superimposed wafer W first wafer Wc central portion We peripheral portion

Claims (15)

A method of processing a polymerized substrate having a first substrate and a second substrate bonded together, comprising:
At least a first film and a second film are formed at the interface between the first substrate and the second substrate at the peripheral edge of the first substrate to be removed,
forming a first unbonded region with reduced bonding strength in the first film at the interface between the first substrate and the second substrate;
forming a second unbonded region with reduced bonding strength at the interface between the second film of the first substrate and the first substrate;
forming a peripheral modified layer that serves as a starting point for peeling of the peripheral edge along the boundary between the peripheral edge of the first substrate and the central portion of the first substrate;
and removing the peripheral edge portion from the polymerized substrate starting from the peripheral edge modification layer. an oxide film as the first film and a device layer as the second film are formed at the interface between the first substrate and the second substrate;
2. The method according to claim 1, wherein the first laser beam irradiated to form the first unbonded region has an absorptive property with respect to the oxide film and has a reflective property with respect to the device layer. Processing method. 3. The processing method according to claim 2, wherein said first laser light has an infrared wavelength. an oxide film as the first film and a device layer as the second film are formed at the interface between the first substrate and the second substrate;
4. The method according to any one of claims 1 to 3, wherein the second laser beam irradiated to form the second unbonded region has absorptive properties with respect to the device layer and has transmissive properties with respect to the oxide film. The processing method according to any one of the items. 5. The processing method according to claim 4, wherein said second laser light has a near-infrared wavelength. A third laser beam irradiated to the inside of the first substrate when forming the peripheral modified layer is the same as the second laser beam irradiated when forming the second unbonded region, The processing method according to claim 4 or 5. 3. An irradiation range of a first laser beam irradiated to form said first unbonded region and an irradiation range of a second laser beam irradiated to form said second unbonded region overlap each other. 7. The processing method according to any one of 1 to 6. A processing system for processing a superimposed substrate having a first substrate and a second substrate bonded together, comprising:
At least a first film and a second film are formed at the interface between the first substrate and the second substrate at the peripheral edge of the first substrate to be removed,
a first laser irradiator forming a first unbonded region with reduced bonding strength in the first film at the interface between the first substrate and the second substrate;
A processing system comprising: a second laser irradiator that forms a second unbonded region with reduced bonding strength at an interface between the second film on the first substrate and the first substrate. an oxide film as the first film and a device layer as the second film are formed at the interface between the first substrate and the second substrate;
9. The method according to claim 8, wherein the first laser beam irradiated to form the first unbonded region has absorptive properties with respect to the oxide film and has reflective properties with respect to the device layer. processing system. 10. The processing system of claim 9, wherein said first laser light has an infrared wavelength. an oxide film as the first film and a device layer as the second film are formed at the interface between the first substrate and the second substrate;
11. The method according to any one of claims 8 to 10, wherein the second laser beam irradiated to form the second unbonded region has absorptive properties with respect to the device layer and has transmissive properties with respect to the oxide film. A processing system according to any one of the preceding paragraphs. 12. The processing system of claim 11, wherein said second laser light has a near-infrared wavelength. A control unit that controls the operation of the second laser irradiation unit,
In the second laser irradiating unit, the control unit performs peripheral edge reforming that serves as a starting point for peeling of the peripheral edge along the boundary between the peripheral edge of the first substrate and the central portion of the first substrate. A treatment system according to any one of claims 8 to 12, wherein the control to form a layer is implemented. The control unit controls the second laser beam to be irradiated to form the second unbonded region as the third laser beam to be irradiated to the inside of the first substrate during formation of the modified peripheral layer. 14. The processing system according to claim 13, which executes control for irradiating the same laser light. A control unit that controls the operation of the first laser irradiation unit and the second laser irradiation unit,
setting an irradiation range of a first laser beam irradiated to form the first unbonded region and an irradiation range of a second laser beam irradiated to form the second unbonded region so as to overlap; A processing system according to any one of claims 8 to 14, which performs control.

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