JP7814972B2 - Method for processing laminated substrates and substrate processing system - Google Patents

Description

The present disclosure relates to a method for processing a polymeric substrate and a substrate processing system.

Patent Document 1 discloses a substrate processing system that includes a modified layer forming device that forms a modified layer inside the first substrate to be removed along the boundary between the peripheral and central portions of the first substrate, which is a laminated substrate formed by bonding a first substrate and a second substrate, and a peripheral edge removing device that removes the peripheral portion of the first substrate using the modified layer as a base point.

International Publication No. 2019/176589

The technology disclosed herein appropriately removes the peripheral edge of a first substrate in a laminated substrate in which a first substrate and a second substrate are bonded together.

One aspect of the present disclosure is a method for treating a laminated substrate in which a first substrate and a second substrate are bonded, in which at least a first film and a second film are formed at the interface between the first substrate and the second substrate, and includes forming a first unbonded region in the first film at the interface between the first substrate and the second substrate, where the bonding strength is reduced, and forming a second unbonded region in the first substrate, where the bonding strength is reduced, at the interface between the second film and the first substrate.

According to the present disclosure, in a laminated substrate in which a first substrate and a second substrate are bonded together, the peripheral edge of the first substrate can be appropriately removed.

FIG. 2 is a side view showing a configuration example of an overlapping wafer according to an embodiment. 2 is an explanatory diagram showing a cross section of a peripheral portion of the overlapping wafer shown in FIG. 1 . FIG. 1 is a plan view showing an outline of the configuration of a wafer processing system according to an embodiment of the present invention. FIG. 2 is a plan view showing the outline of the configuration of an interface reforming device and an internal reforming device. FIG. 2 is a side view showing the outline of the configuration of an interface reformer and an internal reformer. 10A and 10B are explanatory views showing how a first unbonded region is formed on the overlapping wafer. FIG. 10 is an explanatory view showing a first unbonded region formed on the overlapping wafer. 10A and 10B are explanatory views showing how a second unbonded region is formed on the overlapping wafer. FIG. 10 is an explanatory view showing a second unbonded region formed on the overlapping wafer. 10A and 10B are explanatory views showing how a modified layer is formed on an overlapping wafer. FIG. 2 is an explanatory diagram showing a modified layer formed on an overlapping wafer. 10A and 10B are explanatory views showing how edge trim is formed on an overlapping wafer.

In the manufacturing process of semiconductor devices, edge trimming, or the removal of the peripheral edge of a first substrate, may be performed on a composite substrate formed by bonding a first substrate (a silicon substrate such as a semiconductor) and a second substrate, the first substrate having a device layer containing multiple electronic circuits and a bonding film (e.g., an oxide film) formed on its surface.

Edge trimming of the first substrate is performed using, for example, the substrate processing system disclosed in Patent Document 1. That is, a modified layer is formed by irradiating the interior of the first substrate with internal laser light, and the peripheral portion of the first substrate is removed using this modified layer as a starting point. Furthermore, according to the substrate processing system described in Patent Document 1, a modified surface is formed by irradiating an oxide film formed at the interface between the first and second substrates with interface laser light, thereby reducing the bonding strength between the first and second substrates at the peripheral portion and allowing for appropriate removal of the peripheral portion.

However, at the interface between the first and second substrates in the peripheral area of the removal target, the device layer and the bonding film (oxide film) may be present together, depending on various factors, such as the results of substrate processing in a previous process or the conditions when bonding the first and second substrates. In other words, as described above, the device layer and bonding film are formed on the surface of the first substrate, but the surface of the first substrate in the peripheral area of the removal target may include a mixture of a bonding portion with the device layer and a bonding portion with the bonding film.

As disclosed in Patent Document 1, when forming the modified surface, the oxide film formed at the interface between the first and second substrates is irradiated with interface laser light. However, if the device layer and the bonding film are mixed within the irradiation area of this interface laser light, the modified surface may not be formed properly, and the peripheral edge of the first substrate may not be properly removed.

The technology disclosed herein has been developed in light of the above circumstances, and in a laminated substrate in which a first substrate and a second substrate are bonded together, the peripheral edge of the first substrate is appropriately removed. Below, a wafer processing system as a processing system and a wafer processing method as a processing method according to this embodiment will be described with reference to the drawings. Note that in this specification and drawings, elements having substantially the same functional configuration will be assigned the same reference numerals, and redundant description will be omitted.

In a wafer processing system 1 according to this embodiment, which will be described later, processing is performed on a bonded wafer T, which is formed by bonding a first wafer W and a second wafer S, as shown in FIG. 1. A wafer is an example of a substrate. Hereinafter, the surface of the first wafer W that is bonded to the second wafer S will be referred to as the front surface Wa, and the surface opposite the front surface Wa will be referred to as the back surface Wb. Similarly, the surface of the second wafer S that is bonded to the first wafer W will be referred to as the front surface Sa, and the surface opposite the front surface Sa will be referred to as the back surface Sb.

The first wafer W is a semiconductor wafer such as a silicon substrate, and has a device layer Dw including multiple devices formed on its front surface Wa. A bonding film Fw is further formed on the device layer Dw, and the first wafer W is bonded to the second wafer S via the bonding film Fw. Examples of the bonding film Fw include an oxide film (THOX film, SiO ₂ film, TEOS film), a SiC film, a SiCN film, or an adhesive. The peripheral edge We of the first wafer W is chamfered, and the cross-section of the peripheral edge We decreases in thickness toward its tip. The peripheral edge We is the portion to be removed in the edge trimming process described below, and extends, for example, from 0.5 mm to 3 mm radially from the outer edge of the first wafer W. In the following description, the region of the first wafer W radially inward of the peripheral edge We to be removed may be referred to as the central region We.

The second wafer S has, for example, a configuration similar to that of the first wafer W, with a device layer Ds and a bonding film Fs formed on the surface Sa, and the peripheral edge being chamfered. Note that the second wafer S does not have to be a device wafer on which the device layer Ds is formed, but may also be, for example, a support wafer that supports the first wafer W. In such a case, the second wafer S functions as a protective material that protects the device layer Dw of the first wafer W.

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

2, the device layer Dw and the bonding film Fw may be mixed at the interface between the first wafer W and the second wafer S at the peripheral edge We to be removed, where the laser light is irradiated in the edge trimming described below. More specifically, the device layer Dw formed on the surface of the first wafer W may extend beyond the peripheral edge We to be removed due to various factors.
In the wafer processing system 1 according to this embodiment, even if the formation range of the device layer Dw deviates from the peripheral edge portion We to be removed, the peripheral edge portion We is appropriately removed from the overlapping wafer T.

As shown in FIG. 3, wafer processing system 1 has a configuration in which load/unload station 2 and processing station 3 are integrally connected. In load/unload station 2, for example, a cassette C capable of containing multiple overlapping wafers T is loaded and unloaded between the load/unload station 2 and the outside. Processing station 3 is equipped with various processing devices that perform the desired processing on overlapping wafers T.

The loading/unloading station 2 is provided with a cassette mounting table 10 on which a cassette C capable of storing multiple overlapping wafers T is mounted. Furthermore, a wafer transfer device 20 is provided adjacent to the cassette mounting table 10 on the positive X-axis side of the cassette mounting table 10. The wafer transfer device 20 moves on a transfer path 21 extending in the Y-axis direction, and is configured to be able to transfer overlapping wafers T between the cassette C on the cassette mounting table 10 and a transition device 30, which will be described later.

In the loading/unloading station 2, a transition device 30 is provided adjacent to the wafer transfer device 20 on the positive X-axis side of the wafer transfer device 20, for transferring the overlapped wafer T between the processing station 3 and the wafer transfer device 20.

Processing station 3 is equipped with a wafer transfer device 40, an interface modification device 50, an internal modification device 60, an edge removal device 70, and a cleaning device 80.

The wafer transfer device 40 is located on the positive X-axis side of the transition device 30. The wafer transfer device 40 is configured to be freely movable on a transfer path 41 extending in the X-axis direction, and is configured to be able to transfer the overlapped wafer T to the transition device 30, interface modification device 50, internal modification device 60, edge removal device 70, and cleaning device 80 in the transfer station 2.

The interface modification device 50 serving as the first laser irradiation unit irradiates the interface between the first wafer W and the second wafer S with pulsed interface laser light L1 (see FIG. 6 ) to form a first unbonded region Ae1 where the bonding strength between the first wafer W and the second wafer S is reduced. 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, for example, laser light having an infrared wavelength such as a CO ₂ laser, is selected.

As shown in Figures 4 and 5, the interface modification device 50 has a chuck 100 that holds the overlapped wafer T on its upper surface. With the first wafer W on top and the second wafer S on the bottom, the chuck 100 suction-holds the back surface Sb of the second wafer S. The chuck 100 is supported by a slider table 102 via an air bearing 101. A rotation mechanism 103 is provided on the underside of the slider table 102. The rotation mechanism 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to be rotatable about a vertical axis by the rotation mechanism 103 via the air bearing 101. The slider table 102 is configured to be movable on rails 106 extending in the Y-axis direction on a base 105 via a movement mechanism 104 provided on its underside. The drive source of the movement mechanism 104 is not particularly limited, but a linear motor, for example, is used.

A laser irradiation unit 110 is provided above the chuck 100. The laser irradiation unit 110 includes a laser head 111 and a lens 112. The lens 112 is a cylindrical member provided on the underside of the laser head 111, and irradiates the interior of the overlapped wafer T held by the chuck 100, more specifically the interface between the first wafer W and the second wafer S, with interface laser light L1. This modifies the portion of the overlapped wafer T irradiated with the interface laser light L1, forming a first unbonded region Ae1 in which the bonding strength between the first wafer W and the second wafer S is reduced. In one example, the first unbonded region Ae1 is formed at the interface corresponding to the region where the bonding film Fw is formed on the front surface Wa of the first wafer W.

The laser head 111 is supported by a support member 113. The laser head 111 is configured to be able to move up and down freely by an elevating mechanism 115 along rails 114 extending in the vertical direction. The laser head 111 is also configured to be able to move freely in the Y-axis direction by a moving mechanism 116. The elevating 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, on the positive Y-axis side of the laser head 111. The imaging mechanism 120 includes one or more cameras 121, such as a macro camera or a micro camera, and captures an image of the outer edge of the laminated 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 the object. The imaging mechanism 120 may be configured to be able to move up and down freely using an elevator mechanism 122, and may also be configured to be able to move freely in the Y-axis direction using a movement mechanism 123.

In the illustrated example, the chuck 100 is configured to be rotatable relative to the laser head 111 and movable horizontally by the rotation mechanism 103 and the movement mechanism 104, but the laser head 111 may also be configured to be rotatable relative to the chuck 100 and movable horizontally. Also, both the chuck 100 and the laser head 111 may be configured to be rotatable relative to each other and movable horizontally.

The internal modification device 60 serving as the second laser irradiation unit has, in one example, a configuration similar to that of the interface modification device 50. That is, the internal modification device 60 includes a chuck 200 that holds the overlapped wafer T on its upper surface, a laser irradiation unit 210 that irradiates the overlapped wafer T held on the chuck 200 with internal laser light, and an imaging mechanism 220 that images the overlapped wafer T on the chuck 200.

The chuck 200 is configured to be rotatable about a vertical axis by a rotation mechanism 203 and to be movable horizontally by a movement mechanism 204 .
The laser irradiation unit 210 includes a laser head 211 and a lens 212. The laser irradiation unit 210 is configured so as to be movable up and down by an elevator mechanism 215, and is also configured so as to be movable in the Y-axis direction by a moving mechanism 216.
The imaging mechanism 220 includes a camera 221 that captures an image of the outer edge of the overlapped wafer T held by the chuck 200 , a lifting mechanism 222 , and a moving mechanism 223 .

The chuck 200 and the laser irradiation unit 210 may be configured to be rotatable relative to each other and movable horizontally by the rotation mechanism 203 and the movement mechanism 204, or the laser irradiation unit 210 may be configured to be rotatable relative to the chuck 200 and movable horizontally. Alternatively, both the chuck 200 and the laser irradiation unit 210 may be configured to be rotatable relative to each other and movable horizontally.

In the internal modification device 60 according to the technology of the present disclosure, the laser irradiation unit 210 irradiates the interior of the first wafer W with pulses of second internal laser light L3 (see FIG. 10 ) to form a peripheral modified layer M1 that serves as the base point for peeling the peripheral edge portion We, and a divided modified layer M2 that serves as the base point for dividing the peripheral edge portion We into small pieces. For example, the second internal laser light L3 is selected to be laser light having a wavelength that causes multiphoton absorption in the first wafer W, such as laser light having a near-infrared wavelength from a fiber laser or YAG laser.

In addition, in this embodiment, the laser irradiation unit 210 irradiates the interface between the first wafer W and the second wafer S with a similar first internal laser beam L2 (see FIG. 8 ), forming a second unbonded region Ae2 where the bonding strength between the first wafer W and the second wafer S is reduced. In one example, the second unbonded region Ae2 is formed at the interface corresponding to the region where the device layer Dw is formed on the front surface Wa of the first wafer W. The first internal laser beam L2 may be, for example, a laser beam having a wavelength that transmits 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, such as a laser beam having a near-infrared wavelength from a fiber laser, YAG laser, or the like.

In the internal modification device 60, the second internal laser light L3 for forming the peripheral modified layer M1 and the divided modified layer M2 and the first internal laser light L2 for forming the second unbonded region Ae2 may be the same laser light or different laser lights. In other words, the laser irradiation unit 210 includes at least one light source for irradiating the first internal laser light L2 and the second internal laser light L3.

The edge removal device 70 removes the edge portion We of the first wafer W, i.e., performs edge trimming, using the edge modification layer M1 formed in the internal modification device 60 as a starting point. Any edge trimming method can be selected. In one example, the edge removal device 70 may insert a wedge-shaped blade. Alternatively, for example, an air blow or water jet may be sprayed toward the edge portion We to apply an impact to the edge portion We.

The cleaning device 80 performs a cleaning process on the first wafer W and second wafer S after edge trimming by the edge removal device 70, removing particles from these wafers. The cleaning method can be selected arbitrarily.

The wafer processing system 1 described above is provided with a control device 90. The control device 90 is, for example, a computer, and has a program storage unit (not shown). The program storage unit stores a program that controls the processing of the laminated wafer T in the wafer processing system 1. The program storage unit also stores a program that controls the operation of the drive systems of the various processing devices and transport devices described above to achieve the wafer processing described below in the wafer processing system 1. The program may be recorded on a computer-readable storage medium H and installed from the storage medium H into the control device 90. The storage medium H may be temporary or non-temporary.

Next, we will explain wafer processing performed using the wafer processing system 1 configured as described above. In this embodiment, the first wafer W and the second wafer S are bonded together to form a laminated wafer T in advance.

First, a cassette C containing multiple overlapping wafers T is placed on the cassette mounting table 10 of the loading/unloading station 2. Next, the overlapping wafers T are removed from the cassette C by the wafer transfer device 20 and transferred to the interface modification device 50 via the transition device 30 and wafer transfer device 40.

In the interface modification device 50, first, the overlapped 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 capture an image of the outer edge of the first wafer W. At the first imaging position, while the chuck 100 is rotating, the imaging mechanism 120 captures images of the outer edge of the first wafer W in a 360-degree circumferential direction. The captured images are output from the imaging mechanism 120 to the control device 90.

The control device 90 calculates the amount of eccentricity between the center of the chuck 100 and the center of the first wafer W from the image captured by the imaging mechanism 120. Furthermore, the control device 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. Based on this calculated amount of movement, the control device 90 moves the chuck 100 horizontally along the Y-axis direction, correcting the eccentricity between the center of the chuck 100 and the center of the first wafer W.

The control device 90 also sets the irradiation area of the interface laser light L1 to form the unbonded area Ae based on the position of the outer edge of the first wafer W identified from the image of the imaging mechanism 120. The irradiation area of the interface laser light L1 is set, for example, as an annular area having a desired radial width from the outer edge of the first wafer W. The radial width of the irradiation area of the interface laser light L1 is set to a width that allows appropriate removal of the peripheral edge 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 light L1 is set, the chuck 100 and the laser irradiation unit 110 are then rotated relative to each other and moved relative to each other along the Y-axis direction, and 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 interface between the first wafer W and the bonding film Fw or the device layer Dw) is irradiated with pulsed interface laser light L1.
Here, the interface laser light L1 is laser light having a wavelength that is absorbed by the bonding film Fw as described above and reflected by the device layer Dw, for example, laser light having an infrared wavelength such as a _CO2 laser. Therefore, as shown in Fig. 6, the interface laser light L1 is absorbed by the bonding film Fw out of the bonding film Fw (oxide film) and the device layer Dw (see Fig. 2) that are mixed at the interface of the peripheral edge portion We, but is reflected without being absorbed by the device layer Dw.

6 and 7 , in the interface modification device 50, a region at the interface of the peripheral portion We corresponding to the interface between the first wafer W and the bonding film Fw is modified, and a first unbonded region Ae1 is formed in which the bonding strength between the first wafer W and the second wafer S is reduced. In one example, the first unbonded region Ae1 is formed when the irradiated interface laser light L1 is absorbed by the bonding film Fw, which increases the temperature of the bonding film Fw, resulting in peeling at the interface between the first wafer W and the bonding film Fw.
On the other hand, as shown in Figures 6 and 7, at 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 region Ae1 is not formed.

In the embodiments, "interface modification" includes amorphization of the bonding film or device layer at the irradiation position of the interface laser light L1 (or the first internal laser light L2 described below), peeling of the first wafer W from the bonding film or device layer, etc. In other words, in the "unbonded region" in the embodiments, it is sufficient that at least the bonding strength between the first wafer W and the second wafer S is reduced. More specifically, this includes a reduction in bonding strength due to the amorphization of the bonding film, etc., as described above, and neutralization of bonding strength due to peeling of the bonding film, etc.

The laminated wafer T, in which a first unbonded region Ae1 has been formed at the interface between the first wafer W and the second wafer S, is then transported by the wafer transport device 40 to the internal reforming device 60.

In the internal reforming device 60, first, the overlapped 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 capture an image of the outer edge of the first wafer W. At the second imaging position, while the chuck 200 is rotating, the imaging mechanism 220 captures images of the outer edge of the first wafer W in a 360-degree circumferential direction. The captured images are output from the imaging mechanism 220 to the control device 90.

The control device 90 calculates the amount of eccentricity between the center of the chuck 200 and the center of the first wafer W from the image captured by the imaging mechanism 220. Furthermore, the control device 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. Based on this calculated amount of movement, the control device 90 moves the chuck 200 horizontally along the Y-axis direction, thereby correcting the eccentricity between the center of the chuck 200 and the center of the first wafer W.

The control device 90 also sets the irradiation area of the first internal laser light L2 for forming the unbonded area Ae based on the position of the outer edge of the first wafer W identified from the image of the imaging mechanism 220. The irradiation area of the first internal laser light L2 is set to the same range as the formation area of the unbonded area Ae set in the interface modification device 50, i.e., an annular area having a desired radial width from the outer edge of the first wafer W.

Once the eccentricity of the chuck 200 and the first wafer W has been corrected and the irradiation area of the first internal laser light L2 has been set, the chuck 200 and the laser irradiation unit 210 are then rotated relative to each other and moved relative to each other along the Y-axis direction, while irradiating the first internal laser light L2 in pulses onto the interface between the first wafer W and the second wafer S in the set irradiation area (inside the bonding film Fw and the device layer Dw in the example of Figure 8).
Here, the first internal laser light L2 is laser light that transmits through the bonding film Fw as described above and has a wavelength that is absorbed by the device layer Dw, for example, laser light having a near-infrared wavelength such as a YAG laser. The first internal laser light L2 having this near-infrared wavelength has a higher energy density than the interface laser light L1 having an infrared wavelength. Therefore, the first internal laser light L2 has the absorbency for the device layer Dw, which could not be modified by the interface laser light L1.

8 and 9 , the internal reforming apparatus 60 reforms a region of the interface of the peripheral portion We corresponding to the interface between the first wafer W and the device layer Dw, forming a second unbonded region Ae2 in which the bonding strength between the first wafer W and the second wafer S is reduced. In other words, prior to forming the peripheral reformed layer M1 described below, the internal reforming apparatus 60 forms the second unbonded region Ae2 at the interface where the first unbonded region Ae1 could not be formed by the interface reforming apparatus 50. In one example, the second unbonded region Ae2 is formed by irradiating the first internal laser light L2, focusing on the inside of the device layer Dw, destroying the device layer Dw by ablation, resulting in peeling at the interface between the first wafer W and the device layer Dw.
On the other hand, as shown in Figures 8 and 9, at the interface of the peripheral portion We, the first internal laser light L2 is transmitted through the region corresponding to the interface between the first wafer W and the bonding film Fw, and the second unbonded region Ae2 is not formed.

The first internal laser light L2 forms a peripheral modified layer M1, which will be described later, by irradiating the inside of the first wafer W. In other words, multiphoton absorption occurs not only in the device layer Dw but also in the first wafer W (silicon).
Therefore, in the internal reforming device 60, as shown in Figure 8, the focal point position of the first internal laser light L2 is set to a position inside the device layer Dw and at a position where multiphoton absorption does not occur in the first wafer W.

As described above, in the wafer processing system 1 according to this embodiment, the interface between the first wafer W and the second wafer S, which corresponds to the peripheral edge portion We, is irradiated with the interface laser light L1 in the interface modification device 50 and the first internal laser light L2 in the internal modification device 60. As a result, even when the bonding film Fw and the device layer Dw are mixed at the interface of the peripheral edge portion We as shown in FIG. 2 , the unbonded region Ae (the first unbonded region Ae1 and the second unbonded region Ae2) can be appropriately formed over the entire surface of the peripheral edge portion We.
In the edge trimming described below, the peripheral portion We of the first wafer W, which is the target for removal, is removed, but the presence of the first unbonded area Ae1 and the second unbonded area Ae2, which have reduced bonding strength, allows the peripheral portion We to be removed appropriately.

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 focused at a focal point (irradiation position of the second internal laser beam L3) inside the first wafer W (silicon) in the same internal modification device 60. The second internal laser beam L3 is then irradiated in pulses at a predetermined irradiation position inside the first wafer W, thereby sequentially forming a peripheral modified layer M1 and divided modified layers M2, as shown in FIGS. 10 and 11 . The peripheral modified layer M1 serves as a base point for removing the peripheral portion We in the edge trimming process described below. The divided modified layer M2 serves as a base point for dividing the peripheral portion We into small pieces.
In one example, the position where the peripheral modified layer M1 is formed is determined to be slightly radially inward from the radially inner end of the unbonded region Ae.

In the illustrated example, the second internal laser light L3 for forming the peripheral modified layer M1 and the divided modified layer M2 and the first internal laser light L2 for forming the second unbonded region Ae2 are different laser lights. However, as described above, the first internal laser light L2 and the second internal laser light L3 may be the same. In this case, the laser irradiation unit for irradiating the first internal laser light L2 and the laser irradiation unit for irradiating the second internal laser light L3 may be the same, or the respective laser irradiation units may be arranged independently. Similarly, the light source for the first internal laser light L2 and the light source for the second internal laser light L3 may be the same, or the respective light sources may be arranged independently. Furthermore, when the same light source and laser irradiation unit are used in this way, the irradiation conditions of the internal laser light used in each process may be changed as appropriate.

In other words, when the same laser light is used as the first internal-use laser light L2 and the second internal-use laser light L3, various irradiation conditions, such as the focal point position and energy density of the internal-use laser light, may be optimized so that multiphoton absorption of the internal-use laser light does not occur in the first wafer W (silicon) when forming the second unbonded region Ae2. Similarly, various irradiation conditions, such as energy density, may be optimized so that ablation of the device layer Dw by the internal-use laser light does not occur when forming the peripheral modified layer M1 and the divided modified layer M2.

The overlapped wafer T, in which the peripheral modified layer M1 and the divided modified layer M2 have been formed inside the first wafer W, is then transported by the wafer transport device 40 to the peripheral removal device 70.

As shown in FIG. 12, the peripheral edge removal device 70 removes the peripheral edge We of the first wafer W, i.e., performs edge trimming. At this time, the peripheral edge We is peeled from the center of the first wafer W (the radially inner side of the peripheral edge We) using the peripheral modified layer M1 as a base point, and is completely peeled from the second wafer S using the unbonded area Ae (first unbonded area Ae1 and second unbonded area Ae2) as a base point. At this time, the removed peripheral edge We is also broken into small pieces using the divided modified layer M2 as a base point.

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

The overlapped wafer T, from which the peripheral edge We of the first wafer W has been removed, is then transferred by the wafer transfer device 40 to the cleaning device 80. In the cleaning device 80, the first wafer W and/or the second wafer S from which the peripheral edge We has been removed are cleaned.

After that, the laminated wafer T, which has undergone all processing, is transferred by the wafer transfer device 40 to the transition device 30, and then transferred by the wafer transfer device 20 to the cassette C on the cassette mounting table 10. This completes the series of wafer processing steps in the wafer processing system 1.

In the above explanation, the first unbonded region Ae1 is formed in the interface modification device 50, and then the second unbonded region Ae2, peripheral modified layer M1, and divided modified layer M2 are formed in the internal modification device 60. However, the order of wafer processing in the wafer processing system 1 is not limited to this. In other words, the second unbonded region Ae2, peripheral modified layer M1, and divided modified layer M2 may be formed in the internal modification device 60, and then the first unbonded region Ae1 may be formed in the interface modification device 50.

According to the edge trimming technique of this embodiment, even if a bonding film Fw and a device layer Dw are mixed at the interface between the first wafer W and the second wafer S, at least one of a first unbonded region Ae1 and a second unbonded region Ae2, in which the bonding strength between the first wafer W and the second wafer S is reduced, is formed over the entire surface of the peripheral edge We to be removed. In other words, the first unbonded region Ae1 or the second unbonded region Ae2 at least reduces the bonding strength between the first wafer W and the second wafer S over the entire surface of the peripheral edge We, so the peripheral edge We is properly removed from the second wafer S.

In the above embodiment, the irradiation area of the first internal laser light L2 for forming the second unbonded area Ae2 was set to the same range as the irradiation area of the interface laser light L1 for forming the first unbonded area Ae1. In other words, both the interface laser light L1 and the first internal laser light L2 were irradiated onto the entire surface of an annular area (peripheral edge portion We to be removed) having a desired radial width from the outer edge of the first wafer W.
However, the method for determining the irradiation regions of the interface laser light L1 and the first internal laser light L2 is not limited to this. For example, if the formation ranges of the bonding film Fw and the device layer Dw in the peripheral portion We can be detected or if the formation ranges of the bonding film Fw and the device layer Dw are known in advance, the interface laser light L1 may be selectively irradiated onto the formation region of the bonding film Fw, and the first internal laser light L2 may be selectively irradiated onto the formation region of the device layer Dw. In this case, the irradiation regions of the interface laser light L1 and the first internal laser light L2 are reduced compared to the above embodiment, and therefore the amount of energy consumed for forming the unbonded region Ae can be reduced.

In the above embodiment, the first unbonded region Ae1 is formed in the interface modification device 50, and the second unbonded region Ae2, the peripheral modified layer M1, and the divided modified layer M2 are formed in the internal modification device 60. However, the devices for forming the first unbonded region Ae1, the second unbonded region Ae2, the peripheral modified layer M1, and the divided modified layer M2 are not limited to these.
For example, instead of forming the second unbonded region Ae2 in the internal modification device 60, the second unbonded region Ae2 may be further formed in the interface modification device 50. In this case, the laser irradiation unit 110 of the interface modification device 50 may be configured to be able to arbitrarily switch between irradiating the interface laser light L1 and the first internal laser light L2, or the laser irradiation unit for irradiating the interface laser light L1 and the laser irradiation unit for irradiating the first internal laser light L2 may be arranged independently.
Furthermore, for example, instead of forming the second unbonded region Ae2 by the internal modification device 60, a second interface modification device (not shown) for forming the second unbonded region Ae2 may be independently disposed in the wafer processing system 1. In this case, the interface modification device 50 for forming the first unbonded region Ae1 corresponds to the “first interface modification unit” (not shown) according to the technique of the present disclosure.

In the above embodiment, an example was described in which two types of films (bonding film Fw and device layer Dw) are mixed at the interface of the peripheral portion We, and two corresponding types of laser light (interface laser light L1 and first internal laser light L2) are irradiated onto the interface. However, if, for example, two or more types of films are mixed at the interface of the peripheral portion We, two or more types of laser light may be irradiated onto the interface.

The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above-described embodiments 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 region Ae2 second unbonded region L1 interface laser light L2 first internal laser light M1 edge modified layer S second wafer T overlapped wafer W first wafer Wc center portion We edge portion

Claims (12)

A method for treating a laminated substrate in which a first substrate and a second substrate are bonded, comprising:
At least an oxide film as a first film and a device layer as a second film are formed at an interface between the first substrate and the second substrate,
forming a first unbonded region in which the bonding strength is reduced in the first film at the interface between the first substrate and the second substrate;
forming a second unbonded region in the first substrate at an interface between the second film and the first substrate, the second unbonded region having a reduced bonding strength;
Including ,
The method for treating a laminated substrate , wherein the second laser light irradiated when forming the second unbonded region is absorbent for the device layer and transparent for the oxide film . A method for treating a laminated substrate in which a first substrate and a second substrate are bonded, comprising:
At least a first film and a second film are formed at the interface between the first substrate and the second substrate;
forming a first unbonded region in which the bonding strength is reduced in the first film at the interface between the first substrate and the second substrate;
forming a second unbonded region in the first substrate at an interface between the second film and the first substrate, the second unbonded region having a reduced bonding strength;
Including,
A method for processing a laminated substrate, comprising: overlapping an irradiation area of a first laser beam irradiated when forming the first unbonded region with an irradiation area of a second laser beam irradiated when forming the second unbonded region. an oxide film as the first film and a device layer as the second film are formed at an interface between the first substrate and the second substrate;
3. The method for treating a laminated substrate according to claim 2 , wherein the second laser light irradiated when forming the second unbonded region is absorbed by the device layer and is transparent to the oxide film. The method for treating a polymerized substrate according to claim 1 or 3 , wherein the second laser light has a near-infrared wavelength. an oxide film as the first film and a device layer as the second film are formed at an interface between the first substrate and the second substrate;
The method for treating a laminated substrate according to claim 1 , wherein the first laser light irradiated when forming the first unbonded region is absorbent with respect to the oxide film and reflective with respect to the device layer. The method for treating a polymeric substrate according to claim 5 , wherein the first laser light has an infrared wavelength. A processing system for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising:
At least an oxide film as a first film and a device layer as a second film are formed at an interface between the first substrate and the second substrate,
a first laser irradiation unit that forms a first unbonded region in which bonding strength is reduced in the first film at the interface between the first substrate and the second substrate;
a second laser irradiation unit that forms a second unbonded region where bonding strength is reduced at an interface between the second film and the first substrate on the first substrate ,
a second laser beam irradiated when forming the second unbonded region, the second laser beam having absorption properties for the device layer and transmission properties for the oxide film ; A processing system for processing a laminated substrate in which a first substrate and a second substrate are 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;
a first laser irradiation unit that forms a first unbonded region in which bonding strength is reduced in the first film at the interface between the first substrate and the second substrate;
a second laser irradiation unit that forms a second unbonded region in the first substrate at an interface between the second film and the first substrate, where the bonding strength is reduced;
a control unit that controls operations of the first laser irradiation unit and the second laser irradiation unit,
A substrate processing system that executes control to set an overlapping irradiation range of a first laser beam irradiated when forming the first unbonded region and an overlapping irradiation range of a second laser beam irradiated when forming the second unbonded region . an oxide film as the first film and a device layer as the second film are formed at an interface between the first substrate and the second substrate;
9. The substrate processing system according to claim 8 , wherein the second laser light irradiated when forming the second unbonded region is absorbed by the device layer and is transparent to the oxide film. 10. The substrate processing system according to claim 7 , wherein the second laser light has a near-infrared wavelength. an oxide film as the first film and a device layer as the second film are formed at an interface between the first substrate and the second substrate;
11. The substrate processing system according to claim 7, wherein a first laser beam irradiated when forming the first unbonded region is absorbent with respect to the oxide film and reflective with respect to the device layer. The substrate processing system of claim 11 , wherein the first laser light has an infrared wavelength.