Substrate processing method and substrate processing system

Abstract

To provide a substrate processing method and a substrate processing system, removing a non-joint region at a peripheral edge portion including a notch portion formed on a first substrate, in a polymeric substrate where the first substrate and a second substrate are joined to each other.SOLUTION: A method includes: forming a peripheral edge modifying layer, which serves as a starting point of peeling of a peripheral edge portion, by laser light radiation along the boundary between a non-joint region Ae and a joint region Ac of a first substrate; and forming, further also in a notch Wn of the first substrate, a peripheral edge modifying layer (a first part M1a, a second part M1b and a third part M1c) along the notch. When the notch is irradiated with laser, laser light radiated at an intersection M1e between a linear modifying layer at least formed first and a linear modifying layer formed later is modulated to be radiated so that cracks do not progress from an irradiation portion along a linear portion of the notch toward a wafer central portion.SELECTED DRAWING: Figure 17

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing method and a substrate processing system. [Background technology]

[0002] Patent Document 1 discloses a substrate processing system for processing a laminated substrate formed by bonding a first substrate and a second substrate. The substrate processing system disclosed in Patent Document 1 includes a modified layer forming device that forms a modified layer inside the first substrate along the boundary between the peripheral edge and the center of the peripheral edge of the first substrate to be removed, and a peripheral edge removing device that removes the peripheral edge using the modified layer as a base point. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-97506 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology according to the present disclosure appropriately removes the peripheral edge of a first substrate in a laminated substrate formed by bonding a first substrate and a second substrate, taking into consideration the unbonded region in a notch formed in the first substrate. [Means for solving the problem]

[0005] One aspect of the present disclosure is a substrate processing method for processing a laminated substrate in which a first substrate and a second substrate are bonded together, wherein the first substrate has a notch formed by cutting out a portion of a peripheral edge of the first substrate to be removed, a bonded portion bonded to the second substrate, and an unbonded portion not bonded to the second substrate, the method including: irradiating a laser beam between the peripheral edge of the first substrate and a central portion of the first substrate to form a peripheral modified layer that serves as a base point for peeling off the peripheral edge; and, in forming the peripheral modified layer, removing the innermost portion of the unbonded portion in a radial direction of the first substrate at a portion where the notch is formed. When a position on the side of the substrate is used as a reference point, the peripheral modification layer is formed to include: an annular first portion, the reference point of which is located radially inward; at least two straight second portions in the radial direction of the first substrate, the outer peripheral end of which is connected to the first portion in the notch formation portion; and an arc-shaped or straight third portion, the reference point of which is located radially outward, the inner peripheral end of which is connected to the second portion; and the laser light is modulated and irradiated from at least the second portion or the third portion, which is formed first, so that cracks do not extend beyond the intersection of the second portion and the third portion to the joint portion. [Effects of the Invention]

[0006] According to the present disclosure, in a laminated substrate in which a first substrate and a second substrate are bonded together, the peripheral portion of the first substrate can be appropriately removed, taking into account the unbonded area in the notch portion formed in the first substrate. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is an enlarged side view showing a configuration example of an overlapping wafer according to an embodiment. [Figure 2] 1 is an explanatory diagram showing a configuration example of an overlapping wafer according to an embodiment in a plan view. FIG. [Figure 3] 1 is an explanatory diagram showing a configuration example of an overlapping wafer according to an embodiment in a side view. FIG. [Figure 4] 1 is a plan view showing an outline of a configuration example of a wafer processing system according to an embodiment. [Figure 5] FIG. 2 is a plan view showing an example of the configuration of a reformer. [Figure 6] FIG. 2 is a side view showing an example of the configuration of a reformer. [Figure 7] 1A to 1C are explanatory views showing main steps of wafer processing according to an embodiment. [Figure 8] FIG. 2 is a side view showing an example of the configuration of a grinding device. [Figure 9] 1A to 1C are explanatory views showing main steps of grinding according to an embodiment. [Figure 10] FIG. 2 is an explanatory diagram showing a configuration example of a divided modified layer according to an embodiment. [Figure 11] FIG. 2 is an explanatory diagram showing a configuration example of a divided modified layer according to an embodiment. [Figure 12] FIG. 2 is an explanatory diagram showing a configuration example of a divided modified layer according to an embodiment. [Figure 13] FIG. 2 is an explanatory diagram showing a configuration example of a divided modified layer according to an embodiment. [Figure 14] FIG. 2 is a flow chart showing main steps of forming a peripheral modified layer according to an embodiment. [Figure 15] 10 is a graph showing the relationship between the circumferential position of the overlapping wafer and the amount of eccentricity. [Figure 16] FIG. 2 is an explanatory diagram showing a peripheral modification layer according to an embodiment. [Figure 17] FIG. 2 is a partial explanatory view showing a peripheral modification layer according to an embodiment. [Figure 18] FIG. 2 is a partial explanatory view showing a first part of a peripheral modification layer according to an embodiment. [Figure 19] FIG. 4 is a partial explanatory view showing the second or third part of the peripheral modification layer according to the embodiment. [Figure 20] FIG. 3 is an explanatory diagram of the crystal orientation of the first wafer. [Figure 21] FIG. 10 is an explanatory diagram showing another example of the configuration of the peripheral modification layer. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the manufacturing process of semiconductor devices, in a laminated wafer formed by bonding two semiconductor substrates (hereinafter referred to as "wafers"), the peripheral edge of the first wafer may be removed, that is, so-called edge trimming may be performed.

[0009] The edge trimming of the first wafer is performed using, for example, a wafer processing system (substrate processing system) disclosed in Patent Document 1. A modified layer is formed by irradiating the inside of the first wafer (first substrate) with laser light, and the peripheral portion of the first wafer is removed from the modified layer as a base point.

[0010] The edge of the first wafer W, including the peripheral edge We to be removed by edge trimming, is chamfered, with the thickness decreasing toward the tip (see FIG. 1). Therefore, in an overlapped wafer formed by bonding the first wafer W and the second wafer S, the first wafer W and the second wafer S do not come into contact with each other at the chamfered portion where the thickness is reduced, and therefore are not bonded. Furthermore, even in the region radially inward of the chamfered portion, there may be a region where the first wafer W and the second wafer S are not bonded due to various factors, such as the results of wafer processing in a previous process or the conditions for bonding the first wafer W and the second wafer S.

[0011] In the following description, in a laminated wafer T in which a first wafer W and a second wafer S are bonded together, the portion where the first wafer W and the second wafer S are not bonded together may be referred to as an "unbonded portion," and the portion where the first wafer W and the second wafer S are bonded together may be referred to as a "bonded portion."

[0012] As described above, the unbonded portion may occur radially inward of the chamfered portion of the first wafer W. To avoid complicating the explanation, however, as shown in Figures 1 and 2, the unbonded portion corresponding to the chamfered portion may be referred to as the "unbonded region Ae," the bonded portion radially inward of the unbonded region Ae as the "bonded region Ac," and the boundary portion between the unbonded region Ae and the bonded region Ac as the "boundary Ad."

[0013] Here, a notch Wn indicating the direction of crystal orientation is formed in the peripheral edge We of the first wafer W, which is a semiconductor substrate, extending radially inward from the outer edge of the first wafer W. In the area where the notch Wn is formed, an unbonded portion is formed along the notch Wn in a planar view, as shown in FIG. 2 , and therefore an unbonded region Ae is formed radially inward compared to the area where the notch Wn is not formed. Therefore, if a fixed trim width is set from the outer edge of a wafer without a notch Wn, an unbonded portion remains in the area where the notch Wn is formed, causing the first wafer W to float from the second wafer S, which may cause chipping in a later process.

[0014] The technology disclosed herein has been made in consideration of the above circumstances, and in a laminated substrate in which a first substrate and a second substrate are bonded, the peripheral portion of the first substrate is appropriately removed, taking into account the unbonded area in a notch formed in the first substrate. Hereinafter, a wafer processing system as a substrate processing system and a wafer processing method as a substrate 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 designated by the same reference numerals, and redundant description will be omitted.

[0015] 1 and 3, a wafer processing system 1 according to this embodiment, which will be described later, processes an overlapped wafer T as an overlapped substrate formed by bonding a first wafer W as a first substrate and a second wafer S as a second 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.

[0016] The first wafer W is a semiconductor substrate such as a silicon substrate, and has a device layer Dw including a plurality of devices formed on its surface Wa. A bonding film Fw is further formed on the device layer Dw, and the first wafer S is bonded to the device layer Dw via the bonding film Fw. The bonding film Fw may be, for example, an oxide film (THOX film, SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive. As shown in FIG. 1, the peripheral edge We of the first wafer W is chamfered, and the cross section of the peripheral edge We becomes thinner toward its tip. The peripheral edge We is a portion to be removed in the edge trimming process described below, and extends, for example, from 0.5 mm to 3 mm in the radial direction from the outer edge of the first wafer W.

[0017] 2, a notch Wn indicating the crystal orientation is formed in the peripheral edge portion We of the first wafer W. In one example, the notch Wn is formed by cutting out a part of the outer edge portion of the first wafer W. The shape of the notch Wn is not limited to the substantially triangular shape shown in FIG. 2, and may be formed in, for example, a substantially elliptical shape or a substantially circular shape.

[0018] The second wafer S has, for example, the same configuration as the first wafer W, and has a device layer Ds and a bonding film Fs formed on its surface Sa, and its peripheral portion is chamfered and has a notch formed therein. Note that the second wafer S does not necessarily have to be a device wafer on which the device layer Ds is formed, and may be, for example, a support wafer that supports the first wafer W.

[0019] 4, wafer processing system 1 has a configuration in which a load / unload station 2 and a processing station 3 are integrally connected. In load / unload station 2, for example, a FOUP F capable of accommodating a plurality of overlapped 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 desired processing on overlapped wafers T.

[0020] The carry-in / out station 2 is provided with a FOUP mounting table 10 on which a FOUP F capable of accommodating a plurality of overlapped wafers T is mounted. A wafer transfer device 20 is provided adjacent to the FOUP mounting table 10 on the positive X-axis side of the FOUP 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 the overlapped wafers T between the FOUP F on the FOUP mounting table 10 and a transition device 30, which will be described later.

[0021] In the loading / unloading station 2, a transition device 30 for transferring the overlapped wafer T to and from the processing station 3 is provided adjacent to the wafer transfer device 20 on the positive side of the X axis of the wafer transfer device 20.

[0022] In the processing station 3, a wafer transfer device 40, a modifying device 60, an edge removing device 70, a cleaning device 80, and a grinding device 90 are arranged.

[0023] The wafer transfer device 40 is provided on the positive X-axis side of the transition device 30. The wafer transfer device 40 is configured to be 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, the modifying device 60, the edge removing device 70, the cleaning device 80, and the grinding device 90 in the carry-in / out station 2.

[0024] As shown in FIGS. 5 and 6 , the modification apparatus 60 includes a chuck 100 as a substrate holder that holds the overlapped wafer T on its upper surface. The chuck 100 holds the overlapped wafer T by suction. The chuck 100 may hold the back surface Wb of the first wafer W or the back surface Sb of the second wafer S by suction. 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 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 that are provided on a base 105 and extend in the Y-axis direction via a movement mechanism 104 provided on the lower surface thereof. The drive source of the moving mechanism 104 is not particularly limited, but may be, for example, a linear motor. The reforming device 60 also has a control device 61, which will be described later.

[0025] In one embodiment, the slider table 102 includes another rail (not shown) extending in the X-axis direction, another moving mechanism is provided on the other rail, and the chuck 100 is supported on the other moving mechanism. In this way, the slider table 102 according to one embodiment is configured to further move the chuck 100 in the X-axis direction.

[0026] A laser head 110 is provided above the chuck 100. The laser head 110 has a lens 111. The lens 111 is a cylindrical member provided on the lower surface of the laser head 110, and irradiates the inside of the overlapped wafer T held by the chuck 100 with laser light L1. This modifies the portion inside the overlapped wafer T irradiated with the laser light L1, forming a peripheral modified layer M1. Note that in the technology disclosed herein, the laser head 110 and the lens 111 may be collectively referred to as the "laser irradiation unit."

[0027] The laser head 110 is supported by a support member 112. The laser head 110 is configured to be able to move up and down by an elevating mechanism 114 along rails 113 extending in the vertical direction. The laser head 110 is also configured to be able to move in the Y-axis direction by a moving mechanism 115. The elevating mechanism 114 and the moving mechanism 115 are each supported by a support column 116.

[0028] 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 integrated unit, with the macro camera 120 being 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 able to move up and down freely by an elevator mechanism 122, and are further configured to be able to move freely in the Y-axis direction by a movement mechanism 123. Note that in the technology according to the present disclosure, the macro camera 120 and the micro camera 121 may collectively be simply referred to as the "camera."

[0029] The macro camera 120 captures an image of the outer edge of the first wafer W (polymerized wafer T). The image captured by the macro camera 120 is used, for example, for alignment of the first wafer W, which will be described later. The macro camera 120 includes, for example, a coaxial lens, irradiates infrared light (IR), and receives reflected light from an object. The imaging magnification of the macro camera 120 is, for example, 2x.

[0030] The micro camera 121 captures an image of the peripheral edge We of the first wafer W and captures an image of 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 set the irradiation position of the laser light L1. The micro camera 121 is equipped with, for example, a coaxial lens, irradiates infrared light (IR light), and receives reflected light from an object. The imaging magnification of the micro camera 121 is, for example, 10 times, the field of view is approximately 1 / 5 of that of the macro camera 120, and the pixel size is approximately 1 / 5 of that of the macro camera 120.

[0031] In the illustrated example, two cameras, a macro camera 120 and a micro camera 121, are arranged, but the number of cameras provided in the reforming device 60 is not limited to this, and any number of cameras greater than or equal to one may be arranged in the reforming device 60. For example, in cases where it is not necessary to capture an image of the boundary Ad between the bonded area Ac and the unbonded area Ae, such as when the boundary Ad is known in advance, the micro camera 121 may be omitted.

[0032] In the illustrated example, the chuck 100 is configured to be rotatable relative to the laser head 110 and movable in the horizontal direction by the rotation mechanism 103 and the movement mechanism 104, but the laser head 110 may be configured to be rotatable relative to the chuck 100 and movable in the horizontal direction. Alternatively, both the chuck 100 and the laser head 110 may be configured to be rotatable relative to each other and movable in the horizontal direction.

[0033] The modifying device 60 irradiates the inside of the first wafer W with laser light (internal laser light, for example, a YAG laser) to form a peripheral modified layer M1 that serves as a base point for peeling off the peripheral portion We and divided modified layers M2 that serve as base points for dividing the peripheral portion We into small pieces. The configuration of the modifying device 60 is not particularly limited.

[0034] In the illustrated example, two modifying devices 60 are arranged inside the wafer processing system 1, but the number and arrangement of the modifying devices 60 are not limited to this.

[0035] The edge removal device 70 removes the edge portion We of the first wafer W, i.e., performs edge trimming, using the edge modified layer M1 formed by the modification device 60 as a base point. The edge trimming method can be selected arbitrarily. In one example, the edge removal device 70 may insert, for example, a wedge-shaped blade into the interface between the first wafer W and the second wafer S. Alternatively, for example, an air blow or a water jet may be sprayed toward the edge portion We to apply an impact to the edge portion We. Alternatively, for example, ultrasonic waves may be applied to the edge portion We to apply an impact to the edge portion We. Furthermore, for example, the edge portion We may be physically moved in a direction away from the center portion We. Alternatively, the edge portion We may be removed simultaneously when grinding the back surface Wb of the first wafer W using a grinding device 90, which will be described later.

[0036] The cleaning device 80 performs a cleaning process on the first wafer W and the second wafer S after the edge trimming or grinding by the edge removal device 70, thereby removing particles from these wafers. Any cleaning method can be selected.

[0037] The grinding device 90 includes a rotary table (not shown), and, for example, two chucks 131 are provided on the rotary table as substrate holders that suction-hold the overlapped wafer T. The chucks 131 may be, for example, porous chucks.

[0038] The chuck 131 according to this embodiment is held by two chuck bases 132, respectively. As shown in Fig. 8, the chuck base 132 is provided with an inclination adjustment mechanism 134 that adjusts the relative inclination between the grinding unit 140 and the chuck 131. The inclination adjustment mechanism 134 has a fixed shaft 135 provided on the lower surface of the chuck base 132 and a plurality of, for example, two, lift shafts 136. Each lift shaft 136 is configured to be extendable and retractable, and lifts and lowers the chuck base 132.

[0039] The two chucks 131 can be moved to a delivery position and a processing position by rotating a rotary table (not shown). Each of the two chucks 131 is configured to be rotatable about a vertical axis by a rotation mechanism (not shown). At the delivery position, the transfer unit 30 delivers the overlapped wafer T.

[0040] 8, the grinding unit 140 at the processing position has an annular grinding stone 141, a grinding wheel 142 that supports the grinding stone 141, a mount 143 that supports the grinding wheel 142, a spindle 144 that rotates the grinding wheel 142 via the mount 143, and a drive unit 145 that supports the spindle 144. The drive unit 145 has a built-in motor (not shown), for example, and rotates the spindle 144. The grinding unit 140 is also configured to be movable vertically along a support column by an elevation drive unit (not shown).

[0041] The configuration of the grinding device 90 is not limited to this. For example, four chucks 131 may be provided on a rotary table, and the four chucks 131 may be configured to be movable among a transfer position for the overlapped wafer T, a rough grinding unit (not shown) that performs rough grinding of the overlapped wafer T, an intermediate grinding unit (not shown) that performs intermediate grinding of the overlapped wafer T, and a finish grinding unit (not shown) that performs finish grinding of the overlapped wafer T. Furthermore, the grinding device 90 may be provided in the wafer processing system 1 as in this embodiment, or may be provided outside the wafer processing system 1.

[0042] When removing the peripheral edge portion We by the grinding device 90, in the above-described grinding device 90, as shown in Fig. 9(a), the back surface Wb of the first wafer W is ground by rotating the chuck 131 and the grinding wheel 141 while lowering the grinding wheel 141 in a state where the back surface Wb of the first wafer W is in contact with part of the arc of the grinding wheel 141. Then, during the grinding of the entire back surface Wb of the first wafer W, the back surface Wb of the first wafer W is ground to a target thickness while the peripheral edge portion We is removed, as shown in Fig. 9(b).

[0043] The wafer processing system 1 described above is provided with a control device 61 and at least one control device 150. The control device 61 individually controls the operation of each of the modifying devices 60. The control device 150 controls the entire series of wafer processing in the wafer processing system 1.

[0044] Controller 61 and controller 150 process computer-executable instructions that cause reformer 60 and wafer processing system 1 to perform the various steps described in this disclosure, respectively. Controller 61 and controller 150 may be configured to control elements of reformer 60 and wafer processing system 1 to perform the various steps described herein. In one embodiment, some or all of controller 61 may be included in reformer 60, and some or all of controller 150 may be included in wafer processing system 1.

[0045] The control device 61 and the control device 150 may each include a processing unit, a storage unit, and a communication interface. The control device 61 and the control device 150 may each be realized by, for example, a computer. The processing unit may be configured to read a program providing logic or routines enabling various control operations from the storage unit and execute the read program to perform various control operations. The program may be pre-stored in the storage unit or may be acquired via a medium when needed. The acquired program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium may be various computer-readable storage media or a communication line connected to the communication interface. The storage medium may be temporary or non-temporary. The processing unit may be a central processing unit (CPU). The storage unit may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface may communicate between the modification device 60 and the wafer processing system 1 via a communication line such as a local area network (LAN).

[0046] In this embodiment, the control devices 61 are individually installed for the reformers 60, but the control devices 61 may be configured integrally with the control device 150. In other words, the operation of the reformers 60 may be controlled by the control device 150.

[0047] The wafer processing system 1 according to one embodiment is configured as described above, but the configuration of the wafer processing system 1 is not limited to the example shown in the figure.

[0048] Next, a description will be given of wafer processing performed using the wafer processing system 1 configured as shown in Fig. 4. In this embodiment, a first wafer W and a second wafer S are bonded together to form an overlapping wafer T in advance.

[0049] First, the FOUP F containing a plurality of overlapped wafers T is placed on the FOUP placement table 10 of the carry-in / out station 2.

[0050] Next, the overlapped wafer T is taken out of the FOUP F by the wafer transfer device 20 and transferred to the modifying device 60 via the transition device 30.

[0051] In the modification device 60, as shown in FIG. 7(a), laser light L1 is irradiated onto the inside of the first wafer W to form a peripheral modified layer M1 and divided modified layers M2. 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 layers M2 serve as base points for dividing the removed peripheral portion We into small pieces. Furthermore, cracks C extend in the thickness direction of the first wafer W from the peripheral modified layer M1 and divided modified layers M2 formed by the irradiation of the laser light L1. Like the peripheral modified layer M1 and divided modified layers M2, the cracks C serve as base points for removing the peripheral portion We and dividing the peripheral portion We into small pieces. Note that in the drawings used in the following explanation, the divided modified layers M2 may be omitted to avoid complicating the illustrations.

[0052] An example of the configuration of the divided modified layer M2 will be described. In one embodiment, as shown in FIG. 10, multiple divided modified layers M2 are formed so as to extend radially outward from the peripheral modified layer M1 (radial divided modified layers M2a in FIG. 10). In such a case, when removing the peripheral edge portion We using, for example, a peripheral edge removal device 70, the peripheral edge portion We is peeled off from the peripheral modified layer M1 as a base point and divided into multiple pieces by the radial divided modified layers M2a. In this way, the peripheral edge portion We to be removed becomes smaller, making it easier to remove.

[0053] Furthermore, for example, when the first wafer W is ground using a grinding device 90 to remove the peripheral edge portion We, a method of breaking the peripheral edge portion We (edge pieces) into small pieces may be to form multiple annular divided modified layers M2b at arbitrary intervals in a concentric direction with the peripheral modified layer M1, as shown in FIG. 10. In this case, the removed peripheral edge portion We can be made smaller. Furthermore, by controlling the radial intervals between the annular divided modified layers M2b, the size of the small pieces of the peripheral edge portion We to be removed can be controlled.

[0054] Furthermore, instead of the multiple annular divided modified layers M2b, divided modified layers M2c having a spiral shape in a planar view may be formed as shown in Fig. 11. In this case, in the modifying device 60, the chuck 100 or the laser head 110 is moved in the horizontal direction, and the laser head 110 is irradiated with laser light from the chuck 100 while rotating the chuck 100, thereby continuously forming the spiral divided modified layers M2c. As a result, the time required for the processing can be shortened.

[0055] Additionally, when forming a spiral-shaped divided modified layer M2c, a left-handed spiral formation portion M2L and a right-handed spiral formation portion M2R may be formed to overlap, as shown in FIG. 12. In this case, in the modification device 60, the left-handed spiral formation portion M2L and the right-handed spiral formation portion M2R can be formed continuously by irradiating the first wafer W with laser light from the laser head 110 while moving the chuck 100 or the laser head 110 horizontally and rotating the chuck 100 left or right. As a result, the left-handed and right-handed spiral formation portions M3L and M3R intersect with each other, thereby reducing the area surrounded by them in a plan view. This further reduces the removed peripheral edge portion We. Note that while FIG. 12 illustrates the left-handed and right-handed spiral formation portions M2L and M3R separately, this is for ease of illustration; they are formed to overlap the peripheral edge portion We of the same wafer W. Along with the spiral forming portions M2L and M3R, radially divided modified layers M2a may be formed.

[0056] Furthermore, when forming a spiral-shaped divided modified layer M2c, two spiral formation portions M2P and M2Q with different periods (number of turns) may be formed by overlapping them, as shown in FIG. 13. For example, as shown in FIG. 13, the spiral formation portion M3P has two and a half turns, while the formation portion M3Q has one and a half turns. In this case, in the modification device 60, the spiral formation portions M3P and M3Q with different numbers of turns can be formed by irradiating the first wafer W with laser light from the laser head 110 while moving the chuck 100 or the laser head 110 horizontally. As a result, the spiral formation portions M3P and M3Q with different numbers of turns intersect with each other, thereby reducing the area surrounded by them in a plan view. This further reduces the removed peripheral edge portion We. Note that although the two spiral formation portions M2P and M2Q are shown separately in FIG. 13 for ease of illustration, they are formed overlapping the peripheral edge portion We of the same wafer W. Along with the spiral forming portions M2P and M2Q, radially divided modified layers M2a may also be formed.

[0057] The detailed method for forming the peripheral modified layer M1 and the divided modified layers M2 in the reformer 60 will be described later.

[0058] The overlapped wafer T, in which the peripheral modified layer M1 and the divided modified layer M2 are formed inside the first wafer W, is then transferred by the wafer transfer device 40 to the peripheral removing device 70.

[0059] In the peripheral edge removal device 70, as shown in FIG. 7(b), removal of the peripheral edge We of the first wafer W, i.e., edge trimming, is performed. At this time, the peripheral edge We is peeled off 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. At this time, the removed peripheral edge We is broken into small pieces using the divided modified layer M2 as a base point. When removing the peripheral edge We, for example, a wedge-shaped blade B (see FIG. 7(b)) may be inserted into the interface between the first wafer W and the second wafer S that form the overlapped wafer T.

[0060] The overlapped wafer T from which the peripheral edge portion We of the first wafer W has been removed is then transferred by the wafer transfer device 40 to the cleaning device 80.

[0061] In the cleaning apparatus 80, the first wafer W and / or the second wafer S after the peripheral edge portion We has been removed is cleaned. In the cleaning apparatus 80, as shown in Fig. 7(c), for example, the first wafer W and the second wafer S may be irradiated with a cleaning laser beam L2 to modify and remove the irradiated portion of the cleaning laser beam L2, thereby removing (cleaning) any remaining particles and the like.

[0062] The peripheral edge We of the first wafer W is removed by the peripheral edge removing device 70, and the overlapped wafer T is cleaned by the cleaning device 80 and then transferred to the grinding device 90. In the grinding device 90, the first wafer W is ground to a target thickness.

[0063] In one embodiment, 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 by the modifying device 60, is transferred to the grinding device 90 instead of the peripheral removing device 70. In this case, as shown in Fig. 9, the peripheral portion We of the first wafer W is removed by the grinding device 90, and the first wafer W is ground to a target thickness.

[0064] Thereafter, the overlapped wafer T that has undergone all the processing is transferred by the wafer transfer device 20 to the FOUP F on the FOUP mounting table 10 via the transition device 30. In this way, a series of substrate processing steps in the wafer processing system 1 is completed.

[0065] Next, a detailed method for forming the peripheral modified layer M1 in the above-described reformer 60 will be described with reference to the drawings.

[0066] In the modification device 60, first, the overlapped wafer T held by the chuck 100 is moved to a 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 being rotated, the macro camera 120 captures images of the outer edge of the first wafer W in a 360-degree circumferential direction (step St1 in FIG. 14: imaging of edge). The captured images are output from the macro camera 120 to the control device 61.

[0067] The control device 61 identifies the position of the notch Wn formed in the first wafer W held by the chuck 100 from the image captured by the macro camera 120, and calculates the amount of eccentricity between the center of rotation of the chuck 100 and the center of the first wafer W. In one example, the amount of eccentricity between the center of rotation of the chuck 100 and the center of the first wafer W is output as a waveform (sine curve) indicating the relationship between the circumferential position of the first wafer W (horizontal axis in the drawing) and the amount of eccentricity (vertical axis in the drawing) as shown in FIG.

[0068] Furthermore, the control device 61 calculates the movement amount of the chuck 100 based on the calculated eccentricity amount so as to correct the Y-axis component of the eccentricity amount. Based on this calculated movement amount, the control device 61 moves the chuck 100 horizontally along the Y-axis direction to move the chuck 100 to a micro-imaging position (step St2: alignment in FIG. 14). The micro-imaging position is a position where the micro-camera 121 can capture an image of the unbonded region Ae of the first wafer W.

[0069] Next, while rotating the chuck 100, the microcamera 121 captures an image of the unbonded region Ae around the notch Wn in at least the portion of the first wafer W where the notch Wn is formed, more specifically, the boundary Ad between the bonded region Ac and the unbonded region Ae (step St3 in FIG. 14: capturing the boundary Ad). In cases where the formation position of the peripheral modified layer M1 in the portion where the notch Wn is not formed is set in advance, capturing an image of the area around the notch Wn is sufficient to set the irradiation position of the peripheral modified layer M1 in the portion where the notch Wn is formed. In one embodiment, the boundary Ad is captured over 360 degrees in the circumferential direction of the first wafer W. The captured image is output from the microcamera 121 to the control device 61.

[0070] The control device 61 sets the irradiation position of the laser light L1 for forming the peripheral modified layer M1 from the image of the macro camera 120 and the image of the micro camera 121 (step St4 in FIG. 14: setting of irradiation position). Specifically, the control device 61 sets the irradiation position of the laser light L1 as the formation position of the peripheral modified layer M1 with a preset trim width (a preset distance from the outer edge) based on the position of the outer edge of the first wafer W obtained from the image of the macro camera 120. Details of setting the irradiation position of the laser light L1 as the formation position of the peripheral modified layer M1 will be described later.

[0071] In the modification device 60, the chuck 100 is moved horizontally to correct the Y-axis component of the eccentricity based on the calculated eccentricity, thereby correcting the eccentricity between the center of rotation of the chuck 100 and the center of the first wafer W, and laser light L1 is irradiated onto the first wafer W along the set irradiation position to form a peripheral modified layer M1 (step St5 in Figure 14: Formation of peripheral modified layer M1).

[0072] In conventional edge trimming, the peripheral edge We may be removed with a predetermined trim width without considering the irradiation position of the laser beam L1, which is the unbonded area Ae formed corresponding to the notch Wn formed in the first wafer W. However, in this case, the unbonded area Ae may remain on the overlapped wafer T after the edge trimming, which may cause chipping in a later process.

[0073] Therefore, in wafer processing according to this embodiment, a peripheral modified layer M1 is formed as a base point for peeling off the peripheral portion We in the edge trim, taking into consideration the unbonded region Ae corresponding to the notch Wn formed in the first wafer W. More specifically, the peripheral modified layer M1 includes a first portion M1a formed concentrically with the first wafer W in the plan view shown in FIG. 16, a second portion M1b formed in the radial direction at two locations near the notch Wn, and a third portion M1c formed concentrically with the first wafer W or linearly to connect the second portions. A detailed method for setting the irradiation position of the laser beam L1 will be described below.

[0074] First, the outer edge position of the first wafer W on the chuck 100 is identified from the image captured by the macro camera 120. Next, the position of the unbonded region Ae formed at a position corresponding to the notch Wn is identified in the 360-degree circumferential direction of the first wafer W, which position is obtained from information previously acquired during an inspection of bonding the first wafer W and the second wafer S or empirically determined from past inspection results and stored in the memory of the control device 61, or from the image captured by the micro camera 121. Furthermore, the portion of the unbonded region Ae with the largest radial width (hereinafter referred to as "reference point P": see FIG. 16 ) is identified using the outer edge of the portion where the notch Wn is not formed as a reference. In other words, the reference point P, which is the position of the unbonded region (unbonded region Ae) located at the innermost position in the radial direction of the first wafer W corresponding to the notch Wn, is identified from information previously acquired or information captured by imaging with a camera. In addition, the information acquired in advance during inspection when bonding the first wafer W and the second wafer S may be input into the memory unit of the control device 61 by an operator, or may be input into the memory unit of the control device 61 from an inspection device via a host computer in a factory, etc.

[0075] Next, in the portion of the first wafer W where the notch Wn is not formed in the circumferential direction, the irradiation position of the laser light L1 concentric with the first wafer W (the formation position of the first part M1a of the peripheral modified layer M1) is set with a trim width previously set according to the purpose of wafer processing (step St4 in Figure 14).

[0076] Next, at two locations in the notch Wn formation portion, a second portion M1b is formed in the radial direction of the first wafer W, with its outer peripheral end connected to the first portion, and a third portion M1c is formed in an arc shape or a linear shape concentric with the first wafer W so as to connect the inner peripheral end of the second portion. More specifically, the irradiation shape of the laser beam L1 in the notch Wn formation portion in a plan view is set so that the identified reference point P in the notch Wn formation portion coincides with the formation positions of the second portion M1b and the third portion M1c of the peripheral modified layer M1 or is included radially outside (see step St4 in FIG. 14, FIGS. 16, 17). Note that in FIG. 16, the dashed-dotted line indicates that the second portion M1b is formed in the radial direction of the first wafer W; the second portion M1b is not formed in the dashed-dotted line portion, but is formed only in the solid-line portion. Furthermore, the dotted line indicates that the third portion M1c is formed in a concentric circular shape on the first wafer W, and the third portion M1c is not formed in the dotted line portion, but is formed only in the arc of the solid line portion.

[0077] In the modification device 60, the chuck 100 is moved horizontally so as to cancel out the sine curve component of the waveform shown in Fig. 15, and the first wafer W is irradiated with laser light L1 along the set irradiation shape to form the first portion M1a, the second portion M1b, and the third portion M1c of the peripheral modified layer M1 (step St7 in Fig. 14). When the second portion M1b is formed in the radial direction, it is formed by moving the chuck 100 in the Y-axis direction. When the third portion M1c is formed linearly, it is formed by moving the chuck 100 in the XY directions, using a chuck 100 that is also movable in the X-axis direction.

[0078] 17, at the formation positions of the second portion M1b and the third portion M1c of the peripheral modified layer M1, an intersection M1e where the second portion M1b and the third portion M1c intersect is formed. In the peripheral modified layer M1 according to this embodiment, the second portion M1b and the third portion M1c are not formed beyond the intersection M1e in the direction of the bonding region Ac by controlling the irradiation of the laser beam L1 for the reasons explained below.

[0079] That is, when the laser beam L1 is irradiated along the set formation position during the formation of the first portion M1a of the peripheral modified layer M1 in the portion where the notch Wn is not formed, a crack C extends from the first portion M1a as a base point, as shown in Fig. 18. Since the first portion M1a and the crack C are formed continuously in this manner, the first portion M1a is formed suitably as a base point for peeling when removing the peripheral portion We.

[0080] On the other hand, when forming the second portion M1b or the third portion M1c in the portion where the notch Wn is formed, a spatial light modulator (LCOS) (not shown) switches the laser light emitted from the laser head 110 from the laser light L1 to the modulated laser light L3, and the shape and number of the modulated laser light L3 are adjusted. Specifically, the modulated laser light L3 is adjusted to form the second portion M1b or the third portion M1c so that no cracks C are formed or only a small number of cracks C are formed. This prevents the cracks C, which originate from the second portion M1b and the third portion M1c, from extending beyond the intersection M1e, as shown in FIG.

[0081] The order in which the second portion M1b and the third portion M1c are formed is not limited. For example, if the second portion M1b is formed first, the second portion M1b is formed using the modulated laser beam L3, and the third portion M1c is formed using the same laser beam L1 as the first portion M1a. As a result, when a crack C extending from the third portion M1c, which is formed later, reaches the second portion M1b, which is formed first, the stress causing the crack C is alleviated by the second portion M1b, and the crack C does not extend further. As a result, the crack C originating from the second portion M1b and the third portion M1c can be prevented from extending beyond the intersection M1e. Similarly, if the third portion M1c is formed first, the third portion M1c is formed using the modulated laser beam L3, and the second portion M1b is formed using the same laser beam L1 as the first portion M1a.

[0082] According to the embodiment described above, the peripheral modification layer M1 can be formed so as not to leave an unbonded region Ae in the portion where the notch Wn is formed after the edge trim (after the We removal), thereby improving the yield. Also, since the crack C originating from the second portion M1b and the third portion M1c can be prevented from extending beyond the intersection M1e to the bonding region Ac, for example, chipping due to chipping around the intersection M1e in a later process can be suppressed.

[0083] Note that information about the unbonded portion (the formation position of the unbonded portion where the first wafer W and the second wafer S are not bonded), including the formation position of the unbonded region Ae in the peripheral edge portion We (more specifically, the position of the boundary Ad), may be acquired from the image capture results using a camera, for example, or information obtained in advance outside the wafer processing system 1 may be output to the control device 150 at the same time as the overlapped wafer T (FOUP F) is carried into the wafer processing system 1. This information about the unbonded portion can be acquired, for example, by a bonding device (not shown) that bonds the first wafer W and the second wafer S.

[0084] Furthermore, in the above embodiment, the information on the unbonded portion is obtained from the image captured by the camera in the modifying device 60, but the information may be obtained by capturing an image by placing a camera in another device in the wafer processing system 1. The camera capturing an image of the first wafer W may be located, for example, in the transition device 30.

[0085] Furthermore, the position of the boundary Ad between the unbonded area Ae and the bonded area Ac obtained from the image capture by the camera was used as the "information on the unbonded portion" mentioned above, but as mentioned above, the unbonded portion of the first wafer W and the second wafer S can also occur radially inward of the boundary Ad.

[0086] In view of this, it is desirable that the "information on the unbonded portion" acquired prior to the formation of the peripheral modified layer M1 includes the position of the unbonded portion located radially innermost at the interface between the first wafer W and the second wafer S in the portion where the notch Wn is to be formed. In this case, the unbonded portion located radially innermost at the interface between the first wafer W and the second wafer S becomes the "reference point P."

[0087] 20, the first wafer W on which the peripheral modified layer M1 is formed in the wafer processing system 1 according to the technology of the present disclosure has a first crystal orientation CO1 and a second crystal orientation CO2 alternately arranged in the circumferential direction of the first wafer W. A notch Wn formed in the first wafer W indicates this crystal orientation.

[0088] Therefore, in order to properly extend the crack C along the crystal orientation from the peripheral modified layer M1 formed on the first wafer W in the modification device 60, it is necessary to take this crystal orientation into consideration when setting irradiation conditions such as the incident direction of the laser light L1 and the focal point shape of the laser light L1 (longitudinal direction of the focal point).

[0089] Specifically, when forming the first part M1a of the peripheral modified layer M1 concentrically with the first wafer W as in the above embodiment, the irradiation conditions of the laser light L1 are changed according to the crystal orientation (first crystal orientation CO1 or second crystal orientation CO2) shown in Figure 20.

[0090] Furthermore, when forming the second portion M1b and the third portion M1c of the peripheral modified layer M1 as in the above embodiment, the relative irradiation angle of the laser beam L1 with respect to the crystal orientation of the first wafer W changes depending on the irradiation shape of the laser beam L1 in a planar view (the irradiation position of the laser beam L1). Therefore, in the portion where the notch Wn is formed, the irradiation conditions of the laser beam L1 are changed taking into consideration not only the crystal orientation (first crystal orientation CO1 or second crystal orientation CO2) shown in FIG. 20 but also the trim shape of the peripheral portion We (the irradiation shape of the laser beam L1 in a planar view).

[0091] The information about the crystal orientation of the first wafer W may be acquired, for example, simultaneously with the loading of the overlapped wafer T (FOUP F) into the wafer processing system 1 or prior to this.

[0092] In the above description, the peripheral modified layer M1 and the divided modified layer M2 are formed using the modification device 60 as shown in Figure 7, but in addition to this, an interface modification device (not shown) may be provided, in which laser light is irradiated to the bonding portion at the interface between the first wafer W and the second wafer S remaining in the peripheral portion We to modify it and form an area with reduced bonding strength.

[0093] The embodiments disclosed herein should be considered to be illustrative in all respects 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. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0094] 21, in a cross-sectional view, on the back surface Wb of the first wafer W, a peripheral modified layer M1 is formed at a position closer to the center of the wafer than the boundary Ad between the unbonded region Ae and the bonded region Ac. Furthermore, near the bonding surface between the first wafer W and the second wafer S, the peripheral modified layer M1 is formed at a position closer to the boundary Ad. As a result, a crack C is formed obliquely toward the boundary Ad from a midpoint in the thickness direction of the first wafer W to the bonding surface between the first wafer W and the second wafer S.

[0095] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that would be apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above-described effects. [Explanation of symbols]

[0096] 1. Wafer Processing System 60 Reformer 70 Edge removal device 150 control device Ac junction area Ae Unbonded area L1 laser light M1 Peripheral Modification Layer S Second wafer T Polymerized Wafer W First wafer Wc central part We Periphery Wn notch

Claims

1. A substrate processing method for processing a laminated substrate in which a first substrate and a second substrate are bonded together, comprising: The first substrate is a notch formed by cutting out a part of a peripheral edge portion of the first substrate to be removed; a bonding portion bonded to the second substrate; an unbonded portion that is not bonded to the second substrate, irradiating a laser beam between the peripheral edge portion of the first substrate and the central portion of the first substrate to form a peripheral modified layer that serves as a base point for peeling off the peripheral edge portion; When forming the peripheral modification layer, When the innermost position in the radial direction of the first substrate in the notch-forming portion of the unbonded portion is set as a reference point, an annular first portion having the reference point located radially inside; at least two straight second portions in the radial direction of the first substrate, the ends of which on the outer circumferential side are connected to the first portions in the portion where the notch is formed; and a third portion having an arc-shaped or linear shape and having the reference point located radially outward, the third portion being connected to an inner peripheral end of the second portion, A substrate processing method in which the laser light is modulated and irradiated from at least the second part and the third part, whichever is formed first, so that a crack does not extend beyond the intersection of the second part and the third part to the joint portion.

2. irradiating a laser beam to a radially outer side of the first portion of the peripheral modified layer to form a divided modified layer that serves as a starting point for dividing the peripheral portion into small pieces; 2. The substrate processing method of claim 1, wherein the divided modification layer includes a first spiral formation portion formed concentrically with the first substrate, and a second spiral formation portion formed concentrically with the first substrate, in a reverse direction to the first spiral formation portion, and intersecting with the first spiral formation portion.

3. irradiating a laser beam to a radially outer side of the first portion of the peripheral modified layer to form a divided modified layer that serves as a starting point for dividing the peripheral portion into small pieces; 2. The substrate processing method of claim 1, wherein the divided modification layer includes a first spiral formation portion formed concentrically with the first substrate, and a second spiral formation portion concentric with the first substrate, having a different number of turns than the first spiral formation portion, and intersecting with the first spiral formation portion.

4. 4. The substrate processing method according to claim 1, further comprising: setting irradiation conditions for the laser light on the first substrate in consideration of a crystal orientation of the first substrate and a formation shape of the peripheral modification layer in a planar view relative to the notch formation portion.

5. 4. The substrate processing method according to claim 1, further comprising: acquiring information about the unbonded portion by imaging the laminated substrates held by a substrate holder.

6. A substrate processing system for processing a laminated substrate in which a first substrate and a second substrate are bonded together, The first substrate is a notch formed by cutting out a part of a peripheral edge portion of the first substrate to be removed; a bonding portion bonded to the second substrate; an unbonded portion that is not bonded to the second substrate, a modifying device that irradiates a laser beam between the peripheral portion of the first substrate and a central portion of the first substrate to form a peripheral modified layer that serves as a base point for peeling off the peripheral portion; a control device; The control device When forming the peripheral modification layer, When the innermost position in the radial direction of the first substrate in the notch-forming portion of the unbonded portion is set as a reference point, an annular first portion corresponding to a portion where the notch is not formed, the reference point being located radially inward; a second portion of at least two straight lines in the radial direction of the first substrate corresponding to the notch-forming portion; a third portion having an arcuate or linear shape, the third portion having the reference point located radially outward; A substrate processing system that performs control to modulate and irradiate the laser light from at least the second part and the third part, whichever is formed first, so that a crack does not extend beyond the intersection of the second part and the third part to the joint portion.

7. The reformer is a substrate holder for holding the laminated substrate; a laser irradiation unit that irradiates the laser light; a camera that captures an image of the laminated substrate held by the substrate holder, The control device The substrate processing system according to claim 6 , wherein the operation of the modifying device is controlled so as to acquire information about the unbonded portion by imaging the laminated substrate held by the substrate holding unit.

8. the control device performs control to irradiate a laser beam radially outward of the first portion of the peripheral modified layer to form divided modified layers that serve as starting points for dividing the peripheral portion into small pieces; The substrate processing system of claim 6 or 7, wherein the divided modification layer includes a first spiral formation portion formed concentrically with the first substrate, and a second spiral formation portion formed concentrically with the first substrate and in the opposite direction to the first spiral formation portion.

9. the control device performs control to irradiate a laser beam radially outward of the first portion of the peripheral modified layer to form divided modified layers that serve as starting points for dividing the peripheral portion into small pieces; 8. A substrate processing system as described in claim 6 or 7, wherein the divided modification layer includes a first spiral formation portion formed concentrically with the first substrate, and a second spiral formation portion concentric with the first substrate, having the same shape as the first spiral formation portion but a different phase.

Images