JP7706273B2 - Processing method and processing system - Google Patents

Description

This disclosure relates to a processing method and a processing system.

Patent Document 1 discloses a substrate processing system having a modified layer forming device that forms a modified layer inside a first substrate along the boundary between the peripheral and central portions of a first substrate to be removed in a laminated substrate formed by bonding a first substrate and a second substrate, and a peripheral removal 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 improves the productivity of removing the peripheral portion of a first substrate in a laminated substrate in which a first substrate and a second substrate are bonded.

One aspect of the present disclosure is a method for processing a laminated substrate in which a first substrate and a second substrate are bonded together, the method comprising the steps of: forming a peripheral modified layer that serves as a base point for peeling the peripheral portion along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate; detecting a boundary position between the bonded region and the unbonded region over an entire circumference of the first substrate; and detecting the boundary position between the bonded region and the unbonded region over an entire circumference of the first substrate. the peripheral portion is peeled off from the laminated substrate using the peripheral modification layer as a base point; and, of the boundary positions detected around the entire circumference, the boundary position closest to the outer circumferential edge of the first substrate is determined as a reference position, wherein in forming the bonding strength reduced region, the laser light is irradiated onto an annular region on the bonding region side of the reference position.

According to the present disclosure, in a laminated substrate in which a first substrate and a second substrate are bonded, it is possible to appropriately improve the productivity involved in removing the peripheral portion of the first substrate.

FIG. 2 is a side view showing a configuration example of an overlapped wafer according to an embodiment. FIG. 1B is a partially enlarged view of FIG. 1A. 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. 1 is a plan view showing the outline of the configuration of an interface modification device. FIG. 2 is a side view showing the outline of the configuration of an interface modification device. FIG. 2 is an explanatory diagram showing main steps of wafer processing in the wafer processing system. FIG. 2 is a flow diagram showing main steps of wafer processing in the interface modification apparatus. 1 is a cross-sectional view showing a state of an overlapped wafer before a bonding strength reduced region is formed. FIG. 10 is a cross-sectional view showing the state of the overlapped wafer after a bonding strength reduction region is formed. FIG. 11A and 11B are cross-sectional views showing an example of forming an area with reduced adhesive strength on a peripheral edge portion. 11 is a cross-sectional view showing another example of forming an area with reduced adhesive strength on a peripheral edge portion. FIG. 10 is an enlarged cross-sectional view showing an example of forming an area with reduced adhesive strength on a peripheral edge portion. FIG. 11 is an enlarged cross-sectional view showing another example of forming an area with reduced adhesive strength on a peripheral edge portion. FIG. 10 is a cross-sectional view showing the state of the overlapped wafer after a bonding strength reduction region is formed. FIG. 11A and 11B are explanatory views showing another example of forming an adhesive strength reduced region on an overlapping wafer.

In the manufacturing process of semiconductor devices, a composite substrate is formed by bonding a first substrate (a silicon substrate such as a semiconductor) having a number of electronic circuits or other devices formed on its surface to a second substrate, and the peripheral portion of the first wafer may be removed, a process known as edge trimming.

The edge trim of the first substrate is performed, for example, using the substrate processing system disclosed in Patent Document 1. That is, a modified layer is formed by irradiating the inside of the first substrate with laser light, and the peripheral portion is removed from the first substrate using the modified layer as a base point. Also, according to the substrate processing system described in Patent Document 1, a modified surface is formed by irradiating the interface where the first substrate and the second substrate are bonded with laser light, thereby reducing the bonding strength between the first substrate and the second substrate at the peripheral portion and appropriately removing the peripheral portion.

The end of the first substrate, including the peripheral portion to be removed in edge trimming, is chamfered, and the thickness decreases toward the tip. Therefore, in a laminated substrate in which the first substrate and the second substrate are joined, the first substrate and the second substrate do not come into contact with each other at the chamfered portion where the thickness has decreased, and are not joined. Even in a region radially inward from the chamfered portion, a region where the first substrate and the second substrate are not joined may occur due to various factors, such as the results of substrate processing in a previous process and the conditions when the first substrate and the second substrate are joined. Similarly, even in a region radially outward from the chamfered portion, a region where the first substrate and the second substrate are joined may occur.

In the following description, the area of the periphery of the first substrate where the first substrate and the second substrate are not joined may be referred to as the "unbonded area". Also, the area where the first substrate and the second substrate are joined may be referred to as the "joined area". As mentioned above, the unbonded area may occur radially inward of the chamfered portion of the first substrate, but to avoid complicating the description, the unbonded portion corresponding to the chamfered portion may be referred to as the "unbonded area Ae", the joined portion radially inward of the unbonded area Ae as the "joined area Ac", and the boundary portion between the unbonded area Ae and the joint area Ac as the "border Ad" (see Figures 1A and 1B below).

In this unbonded region, the first and second substrates are not bonded, so there is no need to reduce the bonding strength by irradiating the laser light as described above, but Patent Document 1 does not mention taking into consideration this unbonded region (chamfered portion of the substrate). If the unbonded region is irradiated with laser light in this way, portions that do not actually need to be irradiated with laser light will also be irradiated with laser light, so there is room for improvement in the conventional edge trim method from the perspective of improving productivity (throughput).

The technology disclosed herein has been made in consideration of the above circumstances, and appropriately improves the productivity of removing the peripheral portion of a first substrate in a laminated substrate in which a first substrate and a second substrate are bonded. Hereinafter, 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 the drawings, elements having substantially the same functional configuration are denoted with the same reference numerals to avoid redundant description.

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

The first wafer W is a semiconductor wafer such as a silicon substrate, and a device layer Dw including a plurality of devices is formed on the front surface Wa side. A bonding film Fw is further formed on the device layer Dw, and the first wafer S is bonded to the bonding film Fw. As the bonding film Fw, for example, an oxide film (THOX film, _SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive is used. The peripheral portion We of the first wafer W is chamfered, and the cross section of the peripheral portion We becomes thinner toward its tip. The peripheral portion We is a portion to be removed in edge trimming described later, and is, for example, in the range of 0.5 mm to 3 mm in the radial direction from the outer end of the first wafer W.

The second wafer S has, for example, the same configuration as the first wafer W, with a device layer Ds and a bonding film Fs formed on the surface Sa, and the peripheral portion being chamfered. Note that the second wafer S does not have to be a device wafer on which a device layer Ds is formed, and may 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.

As shown in FIG. 1B, the bonding interface between the first wafer W and the second wafer S has a bonding area Ac where the first wafer W and the second wafer S are bonded, and an unbonded area Ae where the first wafer W and the second wafer S are not bonded. FIG. 1B illustrates an example in which the unbonded area Ae roughly coincides with the chamfered area of the first wafer W and the second wafer S, but as described above, the unbonded area Ae can also be formed radially inward from the boundary Ad shown in FIG. 1B. Similarly, the bonding area Ac can also be formed radially outward from the boundary Ad shown in FIG. 1B.

As shown in FIG. 2, the wafer processing system 1 has a configuration in which a loading/unloading station 2 and a processing station 3 are integrally connected. In the loading/unloading station 2, for example, a cassette C capable of housing multiple laminated wafers T is loaded and unloaded between the loading/unloading station 2 and the outside. The processing station 3 is equipped with various processing devices that perform the desired processing on the laminated 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. In addition, a wafer transport 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 transport device 20 moves on a transport path 21 extending in the Y-axis direction, and is configured to be able to transport overlapping wafers T between the cassette C on the cassette mounting table 10 and a transition device 30 described below.

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

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

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

The interface modification device 50 irradiates the interface between the first wafer W and the second wafer S with laser light (interface laser light, for example, a _CO2 laser) to form a bonding strength reduction region R in which the bonding strength between the first wafer W and the second wafer S is reduced.

3A and 3B, the interface modification device 50 has a chuck 100 as a holding unit that holds the overlapped wafer T on the upper surface. The chuck 100 holds the back surface Sb of the second wafer S by suction with the first wafer W on the upper side and the second wafer S on the lower side. The chuck 100 is supported by a slider table 102 via an air bearing 101. A rotation mechanism 103 is provided on the lower surface side of the slider table 102. The rotation mechanism 103 has a built-in motor as a driving source. The chuck 100 is configured to be rotatable around a vertical axis by the rotation mechanism 103 via the air bearing 101. 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 lower surface side. The driving source of the moving mechanism 104 is not particularly limited, but a linear motor is used, for example.

A laser head 110 is provided above the chuck 100 as an irradiation unit. The laser head 110 has a lens 111. The lens 111 is a cylindrical member provided on the underside of the laser head 110, and irradiates the inside 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. This modifies the portion inside the overlapped wafer T that is irradiated with the interface laser light, and forms a bonding strength reduction region R in which the bonding strength between the first wafer W and the second wafer S is reduced.

The laser head 110 is supported by a support member 112. The laser head 110 is configured to be freely raised and lowered by a lifting mechanism 114 along a rail 113 extending in the vertical direction. The laser head 110 is also configured to be freely moved in the Y-axis direction by a moving mechanism 115. The lifting mechanism 114 and the moving mechanism 115 are each supported by a support column 116.

A macro camera 120 and a micro camera 121 are provided above the chuck 100, on the Y-axis positive side of the laser head 110. For example, the macro camera 120 and the micro camera 121 are configured as an integral unit, and the macro camera 120 is disposed on the Y-axis positive side of the micro camera 121. The macro camera 120 and the micro camera 121 are configured to be freely raised and lowered by the lifting mechanism 122, and further configured to be freely moved in the Y-axis direction by the moving mechanism 123.

The macro camera 120, which serves as an outer end imaging section, captures an image of the outer end of the first wafer W (polymerized wafer T). The image captured by the macro camera 120 is used, for example, for the alignment of the first wafer W, which will be described later. The macro camera 120 is equipped with, for example, a coaxial lens, and emits infrared light (IR) and receives reflected light from an object. For example, the imaging magnification of the macro camera 120 is 2x.

The micro camera 121 as a boundary imaging unit images the peripheral portion We of the first wafer W, and images the boundary Ad between the bonded region Ac and the unbonded region Ae. The image captured by the micro camera 121 is used, for example, to determine the irradiation position of the interface laser light described below. The micro camera 121 is equipped with, for example, a coaxial lens, and emits infrared light (IR light), and further receives reflected light from the target object. For example, the imaging magnification of the micro camera 121 is 10 times, the field of view is about 1/5 of that of the macro camera 120, and the pixel size is about 1/5 of that of the macro camera 120.

In the illustrated example, the macro camera 120 and the micro camera 121 are arranged so that the outer edge of the first wafer W and the boundary Ad can be imaged, respectively. However, if there is no need to perform the alignment described below in the interface modification device 50, for example, one of the macro camera 120 or the micro camera 121 can be omitted. In this case, by configuring the boundary Ad to be imaged by the micro camera 121, which has a high imaging magnification, the boundary Ad can be detected with higher accuracy than when the boundary Ad is imaged by the macro camera 120.

In the illustrated example, the chuck 100 is configured to rotate relative to the laser head 110 and move horizontally by the rotation mechanism 103 and the movement mechanism 104, but the laser head 110 may be configured to rotate relative to the chuck 100 and move horizontally. Also, both the chuck 100 and the laser head 110 may be configured to rotate relative to each other and move horizontally.

The internal reforming device 60 irradiates the inside of the first wafer W with laser light (internal laser light, e.g., YAG laser) to form a peripheral reformed layer M1 that serves as a base point for peeling off the peripheral portion We, and a divided reformed layer M2 that serves as a base point for breaking the peripheral portion We into small pieces. The configuration of the internal reforming device 60 is not particularly limited. In one example, the internal reforming device 60 includes a chuck that holds the laminated wafer T on its upper surface, a rotation mechanism that rotates the chuck and the laminated wafer (first wafer W) relatively, a movement mechanism that moves the chuck and the laminated wafer (first wafer W) relatively in the horizontal direction, and a laser irradiation unit (laser head) that irradiates the inside of the first wafer W held by the chuck with internal laser light.

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 base point. Any method for edge trimming can be selected. In one example, the edge removal device 70 may insert a wedge-shaped blade. Also, 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 the second wafer S after the edge trimming by the edge removal device 70, and removes 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 for controlling the processing of the laminated wafer T in the wafer processing system 1. The program storage unit also stores a program for controlling the operation of the drive systems of the various processing devices and transport devices described above to realize the wafer processing described below in the wafer processing system 1. The above program may be recorded in a computer-readable storage medium H and installed from the storage medium H into the control device 90. The above storage medium H may be temporary or non-temporary.

Next, we will explain the 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 placement table 10 of the loading/unloading station 2.

Next, the laminated wafer T is removed from the cassette C by the wafer transport device 20 and transported to the internal reforming device 60 via the transition device 30. In the internal reforming device 60, as shown in FIG. 4(a), an internal laser light L1 is irradiated to the inside of the first wafer W to form a peripheral reformed layer M1 and a divided reformed layer M2. The peripheral reformed layer M1 serves as a base point for removing the peripheral portion We in the edge trim described below. The divided reformed layer M2 serves as a base point for breaking the peripheral portion We into smaller pieces to be removed. In the drawings used in the following explanation, the divided reformed layer M2 may be omitted in order to avoid complicating the illustration.

The laminated wafer T with the peripheral modified layer M1 and the divided modified layer M2 formed inside the first wafer W is then transported to the interface modification device 50 by the wafer transport device 40. In the interface modification device 50, the laminated wafer T (first wafer W) is rotated and moved horizontally along the Y-axis direction while irradiating the interface between the first wafer W and the second wafer S at the peripheral portion We with pulsed interface laser light L2. As a result, as shown in FIG. 4(b), the bonding interface between the first wafer W and the second wafer S is modified. In the embodiment, the modification of the bonding interface includes, for example, amorphization of the bonding film Fw at the irradiation position of the interface laser light L2, peeling of the first wafer W and the second wafer S, etc.

In the interface modification device 50, by modifying the irradiation position of the interface laser light L2 at the interface between the first wafer W and the second wafer S in this manner, a bonding strength reduction region R is formed in which the bonding strength between the first wafer W and the second wafer S is reduced. In the edge trim described below, the peripheral portion We of the first wafer W, which is the target for removal, is removed, and the presence of the bonding strength reduction region R in this manner allows the peripheral portion We to be removed appropriately.

The detailed method for forming the bonding strength reduction region R in the interface modification device 50 will be described later.

The overlapped wafer T with the bond strength reduced region R formed therein is then transferred by the wafer transfer device 40 to the edge removal device 70. In the edge removal device 70, as shown in FIG. 4(c), the edge We of the first wafer W is removed, i.e., edge trimming is performed. At this time, the edge We is peeled from the center of the first wafer W (the radially inner side of the edge We) using the edge modified layer M1 as a base point, and is completely peeled from the second wafer S using the bond strength reduced region R as a base point. At this time, the removed edge We is also broken into small pieces using the divided modified layer M2 as a base point.

When removing the peripheral portion We, a blade B (see FIG. 4(c)), for example having a wedge shape, may be inserted into the interface between the first wafer W and the second wafer S that form the overlapped wafer T.

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

In the cleaning device 80, as shown in FIG. 4(d), for example, a cleaning laser light L3 may be irradiated onto the first wafer W and the second wafer S to modify and remove the irradiated portions of the laser light, thereby removing (cleaning) any remaining particles, etc.

Then, the laminated wafer T that has been subjected to all the processes is transferred by the wafer transfer device 20 to the cassette C on the cassette mounting table 10 via the transition device 30. This completes the series of wafer processing steps in the wafer processing system 1.

In the above description, as shown in Figures 4(a) and 4(b), the peripheral modified layer M1 and the divided modified layer M2 are formed by the internal modification device 60, and then the bonding strength reduction region R is formed by the interface modification device 50. However, the order of wafer processing in the wafer processing system 1 is not limited to this. In other words, the bonding strength reduction region R may be formed by the interface modification device 50, and then the peripheral modified layer M1 and the divided modified layer M2 may be formed by the internal modification device 60.

Next, the detailed method for forming the above-mentioned reduced bonding strength region R will be described with reference to the drawings.

As shown in FIG. 1B, an unbonded area Ae is formed at the bonding interface between the first wafer W and the second wafer S in the overlapped wafer T, for example, corresponding to the chamfered portion of the first wafer W. Since the first wafer W and the second wafer S are not bonded in the unbonded area Ae, there is no need to form the bonding strength reduction area R shown in FIG. 4(b) above. Therefore, in the wafer processing according to this embodiment, the interface modification device 50 detects the unbonded area Ae, and controls so as not to irradiate the interface laser light L2 to the detected unbonded area Ae.

In the interface modification device 50, first, the laminated wafer T held by the chuck 100 is moved to the macro imaging position. The macro imaging position is a position where the macro camera 120 can image the outer edge of the first wafer W. At the macro imaging position, while the chuck 100 is rotating, the macro camera 120 captures images of the outer edge of the first wafer W in the circumferential direction of 360 degrees (Step St1 in FIG. 5: Imaging of edge). The captured image is output from the macro camera 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 of the macro camera 120. Furthermore, the control device 90 calculates the amount of movement of the chuck 100 so as to correct the Y-axis component of the amount of eccentricity based on the calculated amount of eccentricity. The control device 90 moves the chuck 100 horizontally along the Y-axis direction based on this calculated amount of movement, and moves the chuck 100 to a micro-imaging position (step St2: alignment in FIG. 5). The micro-imaging position is a position where the micro-camera 121 can image the unbonded area Ae of the first wafer W. Here, as described above, the field of view of the micro-camera 121 is approximately 1/5 smaller than that of the macro-camera 120, so if the Y-axis component of the amount of eccentricity is not corrected, the unbonded area Ae may not be included in the angle of view of the micro-camera 121 and may not be imaged by the micro-camera 121. For this reason, the correction of the Y-axis component based on the calculated amount of eccentricity can be said to be for moving the chuck 100 to the micro-imaging position.

Next, while rotating the chuck 100, the micro camera 121 captures an image of the unbonded area Ae in the 360° circumferential direction of the first wafer W, more specifically, the boundary Ad between the bonded area Ac and the unbonded area Ae in the 360° circumferential direction of the first wafer W (Step St3 in FIG. 5: Capture of boundary Ad). The captured image is output from the micro camera 121 to the control device 90.

The control device 90 sets the irradiation area of the interface laser light for forming the bonding strength reduction area R from the image of the micro camera 121 (step St4 in FIG. 5: Determining the irradiation area).

The boundary Ad between the bonded area Ac and the unbonded area Ae may be formed radially non-uniformly in the circumferential direction of 360 degrees, as shown in FIG. 6 as an example. In this embodiment, the radial width d1 of the unbonded area Ae (the distance between the boundary Ad and the end of the first wafer W) is calculated in the circumferential direction of 360 degrees of the first wafer W based on the image of the micro camera 121, and the position of the smallest radial width d1 (the position where the unbonded area Ae is formed closest to the end of the first wafer W) is set as the reference position P, and the annular area radially inward from the reference position P is set as the irradiation area of the interface laser light. At this time, the radial width d2 of the bonded area Ac (the distance between the boundary Ad and the formation position of the peripheral modified layer M1) may be further calculated.

Once the irradiation area of the interface laser light has been set, the interface laser light L2 is then irradiated in pulses from the laser head 110 to form a bonding strength reduction area R at the bonding interface between the first wafer W and the second wafer S as shown in FIGS. 4(b) and 7 (step St5 in FIG. 5). Specifically, the frequency of the interface laser light L2 and the rotation speed of the chuck 100 (overlapped wafer T) are controlled so that the laser light is irradiated at the determined pulse pitch Q1, and the movement speed of the chuck 100 (overlapped wafer T) in the Y-axis direction is controlled so that the laser light is irradiated at the determined index pitch Q2.

The bonding strength reduction region R may be formed from the radial inside to the radial outside in the annular region that is the irradiation region of the interface laser light, or from the radial outside to the radial inside.

Then, the laminated wafer T with the bond strength reduction region R formed therein is transported out of the interface modification device 50 by the wafer transport device 40, and the series of processes in the interface modification device 50 is completed.

According to this embodiment, at least one of an unbonded region Ae where the first wafer W and the second wafer S are not bonded, and a region of reduced bonding strength R where the bonding strength is reduced, is formed on the entire surface of the peripheral portion We to be removed. In other words, the unbonded region Ae or the region of reduced bonding strength R at least reduces the bonding strength between the first wafer W and the second wafer S over the entire surface of the peripheral portion We, so that the peripheral portion We is appropriately removed from the second wafer S.

Furthermore, according to this embodiment, the formation area of the bonding strength reduction area R (the area irradiated with the interface laser light L2) is determined to be an annular area radially inward from the position (reference position P) where the radial width d1 of the unbonded area Ae obtained by imaging in step St3 is smallest.

Here, if the microcamera 121 does not detect the unbonded area Ae (more specifically, the boundary Ad) to determine the formation area of the bonding strength reduction area R, it is necessary to start irradiating the interface laser light L2 from the outer peripheral end of the first wafer W and form the bonding strength reduction area R on the entire surface of the peripheral area We in order to reduce the bonding strength between the first wafer W and the second wafer S over the entire surface of the peripheral area We. In this regard, according to the above method related to the technology disclosed herein, by detecting the unbonded area Ae (boundary Ad) by the microcamera 121 and setting the reference position P, the bonding strength reduction area R can be appropriately formed radially inside the reference position P on the peripheral area We as shown in FIG. 7, and the unbonded area Ae is formed over the entire surface radially outside the reference position P. Therefore, the bonding strength can be at least reduced over the entire surface of the peripheral area We to be removed without irradiating the entire surface of the peripheral area We to be removed with laser light. This allows the peripheral portion We to be properly peeled off from the overlapped wafer T, while also shortening the processing time required to form the bonding strength reduced region R and reducing the energy consumed by the laser light irradiation during formation.

Furthermore, according to this embodiment, by determining the formation area of the bonding strength reduction area R to be an annular area radially inward from the reference position P as described above, the interface laser light L2 is not irradiated to the unbonded area Ae radially outward from the reference position P in the peripheral portion We. In other words, by at least omitting the irradiation of the interface laser light L2 to the unbonded area Ae where it is not necessary to reduce the bonding strength, the formation area (processing width) of the bonding strength reduction area R is made smaller than in the conventional method. This reduces the number of times that the interface laser light L2 is irradiated to the bonding interface between the first wafer W and the second wafer S, and appropriately improves the productivity (throughput) related to the formation of the bonding strength reduction area R, while reducing the amount of energy consumed related to the formation of the bonding strength reduction area R.

Furthermore, by reducing the number of times that the interface laser light L2 is irradiated to the interface between the first wafer W and the second wafer S in this manner, the amount of debris/particles generated during the formation of the bonding strength reduction region R can be appropriately reduced.
Furthermore, since the amount of debris/particles generated can be reduced in this manner, when cleaning is performed using the cleaning device 80, the amount of energy consumed and the amount of cleaning liquid can be reduced, and the productivity related to the cleaning can be improved.

Note that, as long as the entire surface of the irradiation region determined in step St4 can be irradiated with the interface laser light L2, the method of irradiating the peripheral portion We with the interface laser light L2 can be determined arbitrarily.
For example, by irradiating the interface laser light L2 in a pulsed manner while rotating the overlapped wafer T and moving the laser head 110 horizontally along the Y-axis direction, the irradiation position of the interface laser light L2 with respect to the irradiation region may be arranged in a spiral shape in a plan view, as shown in FIG. 8A.
In addition, for example, by repeatedly moving the irradiation position of the interface laser light L2 in the radial direction after rotating the overlapped wafer T once, the irradiation position of the interface laser light L2 with respect to the irradiation region may be arranged concentrically with the first wafer W in a plan view, as shown in FIG. 8B.

As shown in FIG. 8A , when the irradiation positions of the interface laser light L2 are arranged in a spiral shape, the number of times the chuck 100 (superimposed wafer T) is moved in the Y-axis direction can be reduced, and the productivity (throughput) related to the formation of the bonding strength reduction region R can be improved.
Furthermore, as shown in FIG. 8B , when the irradiation positions of the interface laser light L2 are arranged concentrically, it becomes easy to control the irradiation position of the interface laser light L2, and the processing width of the bonding strength reduction region R can be appropriately controlled, thereby improving the processing quality related to the edge trim.

Here, in order to properly remove the peripheral portion We of the first wafer W to be removed, it is necessary to irradiate the entire surface of the irradiation area determined in step St3 (the entire surface of the bonding area Ac in the peripheral portion We) with the interface laser light L2. In particular, in order to properly set the removal width of the peripheral portion We, it is necessary to form the bonding strength reduction region R around the entire circumference along the peripheral modification layer M1 formed inside the first wafer W.

9A, at least at the radially inner end (on the peripheral modified layer M1 side) of the irradiation region of the interface laser light L2, it is desirable to arrange the irradiation region of the interface laser light L2 concentrically (see the first region R1 in FIG. 9A) with respect to the first wafer W. By forming the concentric first region R1 along the peripheral modified layer M1 in this manner, the peripheral portion We can be appropriately removed with the desired removal width.
At this time, in the region radially outside the concentric first region R1 that is not related to the accuracy of the processing width, it is desirable to arrange the irradiation region of the interface laser light L2 in a spiral shape (see the second region R2 in Figure 9A) in order to improve the productivity related to the formation of the bonding strength reduction region R.

The first concentric region R1 and the second spiral region R2 may be formed to overlap at least partially in a plan view as shown in FIG. 9B. By forming the first region R1 and the second region R2 to overlap in this manner, a bonding strength reduction region R can be appropriately formed over the entire surface of the irradiation region of the interface laser light L2, and the peripheral portion We can be appropriately peeled off from the overlapped wafer T (first wafer W).

From the viewpoint of properly removing the peripheral portion We of the first wafer W to be removed, it is desirable to form the bonding strength reduction region R so that it overlaps with the boundary Ad between the bonding region Ac and the unbonded region Ae in a plan view all around. In such a case, for example, at least at the radially outer end (the end side of the first wafer W) of the irradiation region of the interface laser light L2, the irradiation region of the interface laser light L2 may be arranged concentrically with respect to the first wafer W, starting from the reference position P. Also, for example, when forming the bonding strength reduction region R in a spiral shape, it is desirable to overlap at least the unbonded region Ae with the irradiation start position (or end position) of the interface laser light L2 for forming the bonding strength reduction region R.

In the above embodiment, as shown in FIG. 7, the interface laser light L2 is irradiated onto the entire surface of the annular region radially inward from the reference position P obtained from the image of the micro camera 121 to form the bonding strength reduction region R, but the method of forming the bonding strength reduction region R is not limited to this.

Specifically, as shown in FIG. 10, the width of the bonding strength reduction region R in the 360-degree circumferential direction of the first wafer W may be determined along the boundary Ad between the bonding region Ac and the unbonded region Ae obtained from the image of the micro camera 121. In other words, the irradiation region of the interface laser light L2 may be determined based on the radial width d2 of the bonding region Ac shown in FIG. 6, and irradiation of the interface laser light L2 may be omitted for the unbonded region Ae where the first wafer W and the second wafer S are not bonded, even if the region is radially inward from the reference position P. This can further reduce the amount of energy consumed in forming the bonding strength reduction region R and the amount of debris/particles generated.

In the above embodiment, as shown in FIG. 4(b), a bonding strength reduction region R is formed at the bonding interface between the first wafer W and the second wafer S (the boundary surface between the bonding film Fw and the bonding film Fs). However, the position where the bonding strength reduction region R is formed is not limited to this as long as the peripheral portion We of the first wafer W can be appropriately removed.

Specifically, as shown in FIG. 11A, for example, the interface laser light L2 may be irradiated to the interface between the device layer Dw formed on the surface Wa of the first wafer W and the first wafer W to form a bonding strength reduction region R. In such a case, in the peripheral edge removal device 70, by applying an impact to the peripheral edge We, a crack is generated from the radial outer end of the bonding strength reduction region R toward the bonding interface between the first wafer W and the second wafer S, and the peripheral edge We is removed from the bonding strength reduction region R as a base point as shown in FIG. 11(b).

More specifically, for example, the interface laser light L2 may be irradiated to the inside of the device layer Dw formed on the surface Wa of the first wafer W to form the bonding strength reduced region R. Even in such a case, in the peripheral edge removal device 70, by applying an impact to the peripheral edge We, a crack is generated from the radial outer end of the bonding strength reduced region R toward the bonding interface between the first wafer W and the second wafer S, and the peripheral edge We is removed.

In the above embodiment, as shown in FIG. 6, the micro camera 121 of the interface modification device 50 detects the position (reference position P) where the radial width d1 of the unbonded area Ae is smallest, but the position where the radial width d1 of the unbonded area Ae is largest may also be detected.

Here, for example, if the unbonded area Ae is formed radially inward of the peripheral modification layer M1 due to poor bonding of the overlapped wafer T, there is a risk that the first wafer W will be left floating relative to the second wafer S after the peripheral portion We is removed.
In this embodiment, the position where the radial width d1 of the unbonded region Ae is the largest may be detected, and if the detected position is radially inside the formation position of the peripheral modified layer M1, a warning may be issued to the operator. In such a case, the wafer processing of the laminated wafer T for which the warning is issued may be immediately stopped, or the detected position may be reset as the radially inner end of the peripheral portion We (the formation position of the peripheral modified layer M1), which is the base point for removing the peripheral portion We.

5, the correction of the amount of eccentricity of the laminated wafer T and the chuck 100 (step St2) and the irradiation of the interface laser light L2 (step St5) are performed independently, but the correction of the amount of eccentricity and the irradiation of the interface laser light L2 may be performed simultaneously. That is, the chuck 100 may be rotated while the interface laser light L2 is irradiated, and further the chuck 100 and the laser head 110 may be moved relatively in the horizontal direction along the Y-axis direction.
5, the correction of the amount of eccentricity of the overlapped wafer T and the chuck 100 (step St2) and the imaging of the boundary Ad (step St3) are performed independently, but the correction of the amount of eccentricity and the imaging of the boundary Ad may be performed simultaneously. That is, the chuck 100 may be rotated to image the boundary Ad in the 360° circumferential direction, and the chuck 100 and the laser head 110 may be moved relatively in the horizontal direction along the Y-axis direction.

The embodiments disclosed herein should be considered in all respects as 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.

REFERENCE SIGNS LIST 1 wafer processing system 50 interface modification device 60 internal modification device 70 edge removal device 90 control device 110 laser head 121 micro camera Ac bonded region Ad boundary Ae unbonded region L2 interface laser light M1 edge modification layer P reference position R bond strength reduced region S second wafer T overlapped wafer W first wafer We edge portion

Claims (12)

A method for treating a laminated substrate in which a first substrate and a second substrate are bonded together, comprising the steps of:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
forming a peripheral modification layer along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate, the peripheral portion serving as a starting point for peeling off the peripheral portion;
detecting a boundary position between the bonded region and the unbonded region over an entire periphery of the first substrate;
irradiating a laser beam toward the bonding region from the detected boundary position to form a bonding strength reduced region that reduces a bonding strength between the first substrate and the second substrate;
peeling the peripheral portion from the laminated substrate using the peripheral modification layer as a base point;
determining, as a reference position, the boundary position closest to an outer circumferential edge of the first substrate among the boundary positions detected around the entire circumference;
In forming the bonding strength reduced region, the laser light is irradiated onto an annular region closer to the bonding region than the reference position. A method for treating a laminated substrate in which a first substrate and a second substrate are bonded together, comprising the steps of:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
forming a peripheral modification layer along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate, the peripheral portion serving as a starting point for peeling off the peripheral portion;
detecting a boundary position between the bonded region and the unbonded region over an entire periphery of the first substrate;
irradiating a laser beam toward the bonding region from the detected boundary position to form a bonding strength reduced region that reduces a bonding strength between the first substrate and the second substrate;
peeling the peripheral portion from the laminated substrate using the peripheral modification layer as a base point;
In forming the region of reduced bonding strength, the laser light is irradiated along the boundary position, and the region of reduced bonding strength is formed only in the bonding region radially inward of the boundary position detected around the entire circumference. A method for treating a laminated substrate in which a first substrate and a second substrate are bonded together, comprising the steps of:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
forming a peripheral modification layer along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate, the peripheral portion serving as a starting point for peeling off the peripheral portion;
detecting a boundary position between the bonded region and the unbonded region over an entire periphery of the first substrate;
irradiating a laser beam toward the bonding region from the detected boundary position to form a bonding strength reduced region that reduces a bonding strength between the first substrate and the second substrate;
peeling the peripheral portion from the laminated substrate using the peripheral modification layer as a base point;
Detecting an outer peripheral edge position of the first substrate over an entire circumference of the first substrate;
calculating an amount of eccentricity between a center of the first substrate and a center of a holder that holds the laminated substrate based on the detected outer circumferential edge position;
the detection of the boundary position is performed while correcting the amount of eccentricity by relatively moving the holding unit and the irradiation unit that irradiates the laser light in a horizontal direction, or after correcting the amount of eccentricity. A method for treating a laminated substrate in which a first substrate and a second substrate are bonded together, comprising the steps of:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
forming a peripheral modification layer along a boundary between the peripheral portion of the first substrate and a central portion of the first substrate, the peripheral portion serving as a starting point for peeling off the peripheral portion;
detecting a boundary position between the bonded region and the unbonded region over an entire periphery of the first substrate;
irradiating a laser beam toward the bonding region from the detected boundary position to form a bonding strength reduced region that reduces a bonding strength between the first substrate and the second substrate;
peeling the peripheral portion from the laminated substrate using the peripheral modification layer as a base point;
Detecting an outer peripheral edge position of the first substrate over an entire circumference of the first substrate;
calculating an amount of eccentricity between a center of the first substrate and a center of a holder that holds the laminated substrate based on the detected outer circumferential edge position;
The forming of the bonding strength reduced region is performed while correcting the amount of eccentricity by relatively moving the holding unit and the irradiating unit that irradiates the laser light in a horizontal direction. The processing method according to any one of claims 1 to 4 , wherein the region of reduced adhesive strength is formed at a bonding interface between the first substrate and the second substrate. a device layer is formed on a surface of the first substrate;
The processing method according to any one of claims 1 to 4 , wherein the region of reduced adhesive strength is formed at an interface between the surface of the first substrate and the device layer, or inside the device layer. A processing system for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
The processing system includes:
an internal modification device for forming a peripheral modification layer that serves as a starting point for peeling off the peripheral portion of the first substrate;
an interface modification device for forming an adhesive strength reduction region that reduces the adhesive strength between the first substrate and the second substrate;
a peripheral edge removing device for peeling off the peripheral edge portion from the laminated substrate;
A control device,
The interface modification device comprises:
a boundary imaging unit that detects a boundary position between the bonded region and the unbonded region over an entire circumference of the first substrate;
an irradiation unit that irradiates a laser beam to form the bonding strength reduced region,
The control device includes:
and performing control to irradiate the laser light toward the bonding region from the boundary position detected by the boundary imaging unit to form the bonding strength reduced region,
The control device further comprises:
performing control to determine, as a reference position, the boundary position that is closest to an outer peripheral edge of the first substrate among the boundary positions detected around the entire circumference;
a processing system that controls the operation of the interface modification device so that, in forming the bonding strength reduced region, the laser light is irradiated onto an annular region that is closer to the bonding region than the reference position. A processing system for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
The processing system includes:
an internal modification device for forming a peripheral modification layer that serves as a starting point for peeling off the peripheral portion of the first substrate;
an interface modification device for forming an adhesive strength reduction region that reduces the adhesive strength between the first substrate and the second substrate;
a peripheral edge removing device for peeling off the peripheral edge portion from the laminated substrate;
A control device,
The interface modification device comprises:
a boundary imaging unit that detects a boundary position between the bonded region and the unbonded region over an entire circumference of the first substrate;
an irradiation unit that irradiates a laser beam to form the bonding strength reduced region,
The control device includes:
and performing control to irradiate the laser light toward the bonding region from the boundary position detected by the boundary imaging unit to form the bonding strength reduced region,
The control device further comprises:
A processing system that controls the operation of the interface modification device so that, in forming the region of reduced bonding strength, the laser light is irradiated along the boundary position, and the region of reduced bonding strength is formed only in the bonding region that is radially inward of the boundary position detected around the entire circumference. A processing system for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
The processing system includes:
an internal modification device for forming a peripheral modification layer that serves as a starting point for peeling off the peripheral portion of the first substrate;
an interface modification device for forming an adhesive strength reduction region that reduces the adhesive strength between the first substrate and the second substrate;
a peripheral edge removing device for peeling off the peripheral edge portion from the laminated substrate;
A control device,
The interface modification device comprises:
a boundary imaging unit that detects a boundary position between the bonded region and the unbonded region over an entire circumference of the first substrate;
an irradiation unit that irradiates a laser beam to form the bonding strength reduced region,
The control device includes:
and performing control to irradiate the laser light toward the bonding region from the boundary position detected by the boundary imaging unit to form the bonding strength reduced region,
The interface modification device comprises:
an outer edge imaging unit that detects an outer circumferential edge position of the first substrate over an entire circumference of the first substrate;
a moving mechanism for relatively moving the laminated substrate and the irradiation unit in a horizontal direction,
The control device further comprises:
performing control to calculate an amount of eccentricity between a center of the first substrate and a center of a holder that holds the laminated substrate, based on the detected outer circumferential end position;
performing control to correct the amount of eccentricity by relatively moving the laminated substrate and the irradiation unit in a horizontal direction;
The processing system described in the present invention controls the operation of the interface modification device to detect the boundary position while correcting the amount of eccentricity by moving the holding unit and the irradiation unit relatively in a horizontal direction, or after correcting the amount of eccentricity . A processing system for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising:
The peripheral portion of the first substrate to be removed is
a bonding region bonded to the second substrate;
a non-bonded region that is not bonded to the second substrate, on a radially outer side of the bonded region;
The processing system includes:
an internal modification device for forming a peripheral modification layer that serves as a starting point for peeling off the peripheral portion of the first substrate;
an interface modification device for forming an adhesive strength reduction region that reduces the adhesive strength between the first substrate and the second substrate;
a peripheral edge removing device for peeling off the peripheral edge portion from the laminated substrate;
A control device,
The interface modification device comprises:
a boundary imaging unit that detects a boundary position between the bonded region and the unbonded region over an entire circumference of the first substrate;
an irradiation unit that irradiates a laser beam to form the bonding strength reduced region,
The control device includes:
and performing control to irradiate the laser light toward the bonding region from the boundary position detected by the boundary imaging unit to form the bonding strength reduced region,
The interface modification device comprises:
an outer edge imaging unit that detects an outer circumferential edge position of the first substrate over an entire circumference of the first substrate;
a moving mechanism for relatively moving the laminated substrate and the irradiation unit in a horizontal direction,
The control device further comprises:
performing control to calculate an amount of eccentricity between a center of the first substrate and a center of a holder that holds the laminated substrate, based on the detected outer circumferential end position;
performing control to correct the amount of eccentricity by relatively moving the laminated substrate and the irradiation unit in a horizontal direction;
a processing system that controls the operation of the interface modification device to form the bonding strength reduced region while correcting the amount of eccentricity by relatively moving the holding unit and the irradiation unit in a horizontal direction . 11. The processing system according to claim 7 , wherein the control device executes control to form the bonding strength reduction region at a bonding interface between the first substrate and the second substrate. a device layer is formed on a surface of the first substrate;
The processing system according to any one of claims 7 to 10 , wherein the control device executes control to form the bonding strength reduction region at the interface between the surface of the first substrate and the device layer, or inside the device layer.

Images