Substrate processing method and substrate processing system

Abstract

A substrate processing method for processing a superposed substrate in which a first substrate and a second substrate are bonded, the substrate processing method including: forming a first peripheral modified region inside the first substrate along a boundary between a peripheral portion and a central portion, which are to be removed, in the first substrate; forming a second peripheral modified portion in the radial direction inside the first substrate at least from the first peripheral modified region on the radial outer side; forming a bonding force reduction region in which the bonding force is reduced in a bonding region between the first substrate and the second substrate on the outside in the radial direction of the first peripheral edge modification region by forming the second peripheral edge modification part; and removing the peripheral portion with the first peripheral modified region and the bonding force reduced region as base points.

Description

Technical Field

[0001] This disclosure relates to a substrate processing method and a substrate processing system. Background Technology

[0002] Patent Document 1 discloses a method for processing an overlapping substrate formed by bonding a first substrate and a second substrate. The processing method includes: cutting a peripheral portion of the first substrate from the top with a thickness smaller than the total thickness of the first substrate, leaving a cutting residue of a desired thickness; and irradiating the cutting residue of the peripheral portion of the first substrate with a laser beam to remove the cutting residue.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-71480 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The technology disclosed herein allows for the appropriate removal of the peripheral portion of the first substrate, which is the target of removal, from an overlapping substrate formed by bonding the first substrate and the second substrate.

[0008] Solution for solving the problem

[0009] One aspect of this disclosure is a substrate processing method for processing an overlapping substrate formed by bonding a first substrate and a second substrate. The substrate processing method includes: forming a first peripheral modification region inside the first substrate along the boundary between a peripheral portion and a central portion of the first substrate that are to be removed; forming a second peripheral modification portion radially outward from at least the first peripheral modification region inside the first substrate; forming a bonding force reduction region radially outward from the first peripheral modification region and in the bonding region between the first substrate and the second substrate by forming the second peripheral modification portion, thereby forming a bonding force reduction region; and removing the peripheral portion based on the first peripheral modification region and the bonding force reduction region.

[0010] The effects of the invention

[0011] According to this disclosure, the peripheral portion of the first substrate, which is the object of removal, can be appropriately removed from an overlapping substrate formed by bonding the first substrate and the second substrate. Attached Figure Description

[0012] Figure 1 This is an illustration of overlapping wafers that are the objects of processing.

[0013] Figure 2This is a top view showing an outline of the structure of the wafer processing system.

[0014] Figure 3 This is a top view showing an outline of the structure of the modification device.

[0015] Figure 4 This is a side view showing an outline of the structure of the modification device.

[0016] Figure 5 This is an explanatory diagram illustrating the formation of a first peripheral modification region and a second peripheral modification portion during wafer processing.

[0017] Figure 6 This is an explanatory diagram illustrating the formation of a second peripheral modification portion during wafer processing.

[0018] Figure 7 This is an explanatory diagram illustrating the formation of the first peripheral modification region during wafer processing.

[0019] Figure 8 This is an explanatory diagram illustrating the removal of the peripheral portion during wafer processing.

[0020] Figure 9 This is an explanatory diagram illustrating the formation of a first peripheral modified region in other embodiments. Detailed Implementation Detailed Implementation

[0021] In the semiconductor device manufacturing process, the first wafer is thinned in an overlapping wafer formed by bonding a first wafer (hereinafter referred to as a "wafer"), which serves as a semiconductor substrate on which multiple electronic circuits and other devices are formed, with a second wafer. Furthermore, prior to the thinning process of the first wafer, an edge trimming process, known as removing the periphery of the first wafer, is performed.

[0022] Edge trimming of the first wafer is performed, for example, by the processing method disclosed in Patent Document 1. In this processing method, as described above, after cutting the periphery of the first substrate from the top, a laser beam is irradiated onto the remaining portion of the cut periphery of the first substrate, and the remaining portion is removed by laser ablation. However, removing the periphery in two stages, especially laser ablation, is time-consuming, and there is room for improvement over conventional edge trimming.

[0023] The technology disclosed herein appropriately removes the peripheral portion of the first substrate, which is the target of removal, from an overlapping substrate formed by bonding a first substrate and a second 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 accompanying drawings. Furthermore, in this specification and the accompanying drawings, elements having substantially the same functional structure are labeled with the same reference numerals, thereby omitting repeated descriptions.

[0024] In the wafer processing system 1 described later in this embodiment, as... Figure 1 As shown, a superimposed wafer T, which is formed by bonding a first wafer W (serving as a first substrate) and a second wafer S (serving as a second substrate), is processed. Hereinafter, in the first wafer W, the side that is bonded to the second wafer S is referred to as surface Wa, and the side opposite to surface Wa is referred to as back surface Wb. Similarly, in the second wafer S, the side that is bonded to the first wafer W is referred to as surface Sa, and the side opposite to surface Sa is referred to as back surface Sb.

[0025] The first wafer W is, for example, a semiconductor wafer such as a silicon substrate, on which at least one film is formed in a stacked manner on the surface Wa side. Hereinafter, the film formed on the surface Wa side will be referred to as the "first stacked film". In this embodiment, the first stacked film includes a device layer Dw and a bonding film Fw. The device layer Dw includes multiple devices. The bonding film Fw is, for example, an oxide film (THOX film, SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive. Furthermore, the first wafer W is bonded to the second wafer S via the bonding film Fw. Additionally, the peripheral portion We of the first wafer W is chamfered, and the thickness of the peripheral portion We decreases towards its leading edge. The peripheral portion We is the portion to be removed during edge trimming, as described later, and is, for example, a radial range of 0.5 mm to 3 mm from the outer end of the first wafer W. Furthermore, in the following description, the region of the first wafer W that is radially inward of the peripheral portion We, which is the target of removal, is sometimes referred to as the central portion Wc.

[0026] The second wafer S, for example, has the same structure as the first wafer W. That is, a device layer Ds and a bonding film Fs are formed on the surface Sa as a second laminate, and the periphery is chamfered. Furthermore, the second wafer S does not need to be a device wafer with the device layer Ds formed; for example, it can be a support wafer supporting the first wafer W. In this case, the second wafer S functions as a protective element protecting the device layer Dw of the first wafer W.

[0027] In the following description, the layers between the first wafer W and the second wafer S are referred to as bonding regions. That is, in this embodiment, the surface Wa, the space between the device layer Dw and the bonding film Fw, the space between the bonding film Fw and the bonding film Fs, the space between the bonding film Fs and the device layer Ds, and the surface Sa are referred to as bonding regions.

[0028] In addition, Figure 1The illustration shows an example where device layers Dw and Ds and bonding films Fw and Fs are formed on the surfaces Wa and Sa of the first wafer W and the second wafer S, respectively, as the first and second stacked films. However, the types and number of layers of the first and second stacked films are not limited to this.

[0029] like Figure 2 As shown, the wafer processing system 1 has a structure that connects the loading / unloading station 2 and the processing station 3 into one unit. The loading / unloading station 2 includes, for example, a container C capable of holding multiple overlapping wafers T, which can be loaded and unloaded from the outside. The processing station 3 is equipped with various processing devices for performing desired processing on the overlapping wafers T.

[0030] The loading / unloading station 2 is equipped with a cassette stage 10 that holds cassettes C capable of accommodating multiple overlapping wafers T. Additionally, a wafer transport device 20 is provided adjacent to the cassette stage 10 on its positive X-axis side. The wafer transport device 20 is configured to move along a transport path 21 extending along the Y-axis and transport overlapping wafers T between the cassettes C of the cassette stage 10 and the transport device 30 described later.

[0031] At the inbound / outbound station 2, on the positive X-axis side of the wafer transport device 20, a transport device 30 for transferring overlapping wafers T between the wafer transport device 20 and the processing station 3 is provided adjacent to the wafer transport device 20.

[0032] Processing station 3 is equipped with a wafer transport device 40, a modification device 50, a peripheral removal device 60, and a cleaning device 70.

[0033] The wafer transport device 40 is disposed on the positive X-axis side of the transport device 30. The wafer transport device 40 is configured to move freely on the transport path 41 extending along the X-axis direction, and is configured to transport overlapping wafers T to the transport device 30, the modification device 50, the peripheral removal device 60 and the cleaning device 70 entering and leaving the transport station 2.

[0034] The modification device 50 irradiates the interior of the first wafer W with a modification laser beam (e.g., a YAG laser or a fiber laser) to form a peripheral modification region and a bonding force reduction region, which serve as the base point for peeling off the peripheral portion We. Additionally, the modification device 50 includes a control device 51, which will be described later.

[0035] like Figure 3 and Figure 4As shown, the modification apparatus 50 has a chuck 100 that holds the overlapping wafer T on the upper surface. The chuck 100 holds the back surface Sb of the second wafer S with the first wafer W positioned on the upper side and the second wafer S positioned on the lower side. The chuck 100 is supported on a slide stage 102 via an air bearing 101. A rotation mechanism 103 is provided on the lower surface of the slide stage 102. The rotation mechanism 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to rotate freely about a vertical axis via the air bearing 101 through the rotation mechanism 103. The slide stage 102 is configured to move freely on a guide rail 106 via a moving mechanism 104 provided on its lower surface, the guide rail 106 extending along the Y-axis on a base 105. Furthermore, the drive source of the moving mechanism 104 is not particularly limited, but a linear motor may be used, for example.

[0036] A laser head 110 is disposed above the holding disk 100. The laser head 110 has a lens 111. The lens 111 is a cylindrical component disposed on the lower surface of the laser head 110, which irradiates a laser beam into the interior of the overlapping wafer T held in the holding disk 100, more specifically into the interior of the first wafer W.

[0037] The laser head 110 is supported by a support member 112. The laser head 110 is configured to move freely up and down along a guide rail 113 extending in the vertical direction via a lifting mechanism 114. In addition, the laser head 110 is configured to move freely in the Y-axis direction via a moving mechanism 115. Furthermore, the lifting mechanism 114 and the moving mechanism 115 are respectively supported by a support column 116.

[0038] A camera mechanism 120 is provided above the holding disk 100 and on the positive Y-axis side of the laser head 110. The camera mechanism 120 has at least one camera. The images captured by the cameras are output to the control device 51 or control device 80, which will be described later. Then, in the modification device 50, the position of the overlapping wafer T on the holding disk 100 is determined based on the image obtained by the camera mechanism 120, and the alignment of the overlapping wafer T and the determination of the laser beam irradiation position are performed based on this position. Furthermore, the camera mechanism 120 is configured to be freely raised and lowered by a lifting mechanism 121, and is configured to be freely movable in the Y-axis direction by a moving mechanism 122. The moving mechanism 122 is supported by a support column 116.

[0039] Furthermore, in the illustrated example, the configuration allows the holding disk 100 to rotate relative to the laser head 110 and move horizontally via the rotating mechanism 103 and the moving mechanism 104. However, it can also be configured so that the laser head 110 can rotate relative to the holding disk 100 and move horizontally. Alternatively, it can be configured so that both the holding disk 100 and the laser head 110 can rotate relative to each other and move horizontally.

[0040] Figure 2 The peripheral removal apparatus 60 shown removes the peripheral portion We of the first wafer W, i.e., edge trimming, based on the peripheral modification region and the bonding force reduction region formed by the modification device 50. The edge trimming method can be arbitrarily selected. In one example, a wedge-shaped blade may be inserted between the first wafer W and the second wafer S in the peripheral removal apparatus 60. Alternatively, for example, an impact may be applied to the peripheral portion We by spraying an air stream or water jet towards it. Alternatively, for example, ultrasonic waves may be applied to the peripheral portion We to apply impact. Furthermore, for example, the peripheral portion We may be physically moved away from the central portion Wc.

[0041] The cleaning device 70 performs a cleaning process on the first wafer W and the second wafer S, which have been edge-trimmed by the peripheral removal device 60, to remove particles from these wafers. The cleaning method can be selected arbitrarily.

[0042] The wafer processing system 1 described above is equipped with a control device 51 and at least one control device 80. The control device 51 independently controls the operation of the modification device 50. The control device 80 uniformly controls a series of wafer processing operations in the wafer processing system 1.

[0043] Control device 51 and control device 80 respectively process computer-executable commands that cause modification device 50 and wafer processing system 1 to perform the various processes described herein. Control device 51 and control device 80 can be configured to control the elements of modification device 50 and wafer processing system 1 to perform the various processes described herein. In one embodiment, part or all of control device 51 may also be included in modification device 50, and part or all of control device 80 may also be included in wafer processing system 1.

[0044] Control device 51 and control device 80 may each include a processing unit, a storage unit, and a communication interface. Control device 51 and control device 80 may be implemented, for example, by a computer. The processing unit can be configured to read a program from the storage unit that provides logic or routines capable of performing various control actions, and execute the read program to perform these control actions. The program may be pre-stored in the storage unit or retrieved via a medium when needed. The retrieved program is stored in the storage unit and read 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 transient or non-transient. The processing unit may be a CPU (Central Processing Unit) or one or more circuits. The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or combinations thereof. The communication interface can also communicate with the modification device 50 and the wafer processing system 1 via communication lines such as LAN (Local Area Network).

[0045] Furthermore, in this embodiment, the control device 51 is provided separately from the modification device 50, but the control device 51 may also be integrally formed with the control device 80. In other words, the operation of the modification device 50 may also be controlled by the control device 80.

[0046] Next, the wafer processing performed using the wafer processing system 1 configured as described above will be explained.

[0047] Furthermore, in this embodiment, before being processed by the wafer processing system 1, the first wafer W and the second wafer S are bonded outside the wafer processing system 1 to pre-form an overlapping wafer T.

[0048] Furthermore, in this embodiment, after processing by the wafer processing system 1, a thinning process is performed outside the wafer processing system 1 to thin the central portion Wc of the first wafer W. The thinning process of the first wafer W is arbitrary. Moreover, the thinning device for the central portion Wc of the first wafer W, such as a grinding device (not shown), can be provided outside the wafer processing system 1 as in this embodiment, or it can be equipped within the wafer processing system 1.

[0049] First, a box C containing multiple overlapping wafers T is placed on the box placement stage 10 of the transfer station 2. Then, the overlapping wafers T in the box C are removed using the wafer transfer device 20 and transferred to the modification device 50 via the transfer device 30 and the wafer transfer device 40.

[0050] In the modification device 50, such as Figures 5-7 As shown, a laser beam L for modification is irradiated into the interior of the first wafer W to form a first peripheral modified portion M1 and a second peripheral modified portion M2 in the circumferential direction when viewed from above. In this embodiment, the first peripheral modified portion M1 is formed after the second peripheral modified portion M2 is formed.

[0051] First, such as Figure 5 and Figure 6 As shown, at least from the first peripheral modification region N1 (the first peripheral modification portion M1 and the first crack C1) described later, a laser beam L is irradiated radially outward, i.e., at the peripheral portion We, onto the interior of the first wafer W to form a second peripheral modification portion M2. At this time, the second peripheral modification portion M2 can be formed from the radially outer side inward, or from the radially inner side outward.

[0052] The second peripheral modified portion M2 is formed near the surface Wa of the first wafer W. Specifically, the distance H in the thickness direction between the second peripheral modified portion M2 and the surface Wa is, for example, within 20 μm.

[0053] Furthermore, adjacent second peripheral modified portions M2 are not connected to each other. That is, cracks originating from the second peripheral modified portion M2 will not reach adjacent second peripheral modified portions M2. To ensure that the second peripheral modified portions M2 are not connected to each other in this way, one or both of the spacing and intensity of the laser beam L irradiating the interior of the first wafer W are controlled. The lower limit of the spacing of the laser beam L, i.e., the spacing P of the second peripheral modified portions M2, is the spacing at which cracks between adjacent second peripheral modified portions M2 are not connected, and the upper limit of the spacing P is the spacing at which the bonding force reduction region R described later can be formed. The spacing P is, for example, 30 μm to 80 μm.

[0054] In this case, the second peripheral modified portion M2 expands and experiences compressive stress, while the region Q1 above the second peripheral modified portion M2 and the region Q2 below the second peripheral modified portion M2 experience tensile stress. That is, tensile stress accumulates in these regions Q1 and Q2, and tensile stress also acts on the surface Wa of the first wafer W. Therefore, compressive stress acts on the upper portion of the first wafer W (the portion above the second peripheral modified portion M2) to cause the upper portion of the first wafer W to warp obliquely upwards, thus causing the peripheral portion Wa to peel off. Figure 6 (The arrow in the image).

[0055] This is because, between the first wafer W and the second wafer S, in the bonding region between the first and second laminated films—that is, the bonding region between the bonding film Fw and the bonding film Fs—an unbonded region is formed radially outward from this bonding region, where peeling is most likely to occur. In this case, corresponding to the compressive stress (warping) of the upper portion of the first wafer W, tensile stress acts in the bonding region between the bonding film Fw and the bonding film Fs, causing a decrease in the bonding force and forming a bonding force reduction region R. This bonding force reduction region R extends between the first peripheral modification region N1 and the outer edge, as described later.

[0056] Furthermore, assuming that adjacent second peripheral modified portions M2 are connected to each other through cracks, compressive stress is released, and no tensile stress acts on the surface Wa of the first wafer W, making it difficult to form a bonding strength reduction region R. Moreover, in the region formed by the second peripheral modified portions M2 and the cracks, the bonding strength decreases, and the peripheral portion is removed with reference to this region. In this regard, according to this embodiment, since the second peripheral modified portions M2 are not connected to each other, it is easy to form a bonding strength reduction region R on the outside of the first wafer W, and the peripheral portion We is removed with reference to this bonding strength reduction region R.

[0057] Furthermore, in this embodiment, since the second peripheral modified portion M2 is formed near the surface Wa of the first wafer W, the tensile stress acting on the surface Wa of the first wafer W increases, making it easier to form a region R with reduced bonding strength.

[0058] Furthermore, if the tensile stress acting on the bonding force reduction region R increases, sometimes a portion of the bonding area between the bonding film Fw and the bonding film Fs may peel off. In this case, by controlling the laser beam L irradiating the interior of the first wafer W, the bonding force reduction region R is formed to extend radially outward toward the first peripheral modification region N1.

[0059] Next, as Figure 5 and Figure 7 As shown, a laser beam L is irradiated into the interior of the first wafer W along the boundary between the peripheral portion We and the central portion Wc to form a first peripheral modified portion M1. The boundary between the peripheral portion We and the central portion Wc is, for example, a boundary extending along the thickness direction of the first wafer W. When the first peripheral modified portion M1 is formed, a first crack C1 extends from the first peripheral modified portion M1 along the boundary between the peripheral portion We and the central portion Wc. The first crack C1 extends to the bonding region of the bonding film Fw and the bonding film Fs. Furthermore, a first peripheral modified region N1 is formed, including the first peripheral modified portion M1 and the first crack C1. The first peripheral modified region N1 extends between the back surface Wb of the first wafer W and the bonding region of the bonding film Fw and the bonding film Fs.

[0060] When the first peripheral modification region N1 is formed, the compressive stress in the upper portion of the first wafer W is released, and the tensile stress in the bonding force reduction region R is released. At this time, in the bonding force reduction region R, the tensile stress is released, for example, from the radially outer side to the inner side (towards the first peripheral modification region N1). Therefore, in the bonding force reduction region R, the bonding film Fw peels off from the bonding film Fs. The peeling in the bonding force reduction region R continues to the first peripheral modification region N1, and the bonding force reduction region R connects with the first peripheral modification region N1. Moreover, these first peripheral modification regions N1 and bonding force reduction regions R become the base points when removing the peripheral portion We.

[0061] The overlapping wafer T, having formed the first peripheral modification region N1 and the bonding strength reduction region R, is then transported to the peripheral removal device 60 via the wafer transport device 40. In the peripheral removal device 60, as... Figure 8 As shown, a blade B is inserted between the first wafer W and the second wafer S to remove the peripheral portion We from the first wafer W. At this time, the peripheral portion We is peeled off from the central portion Wc of the first wafer W, with the first peripheral modification region N1 and the bonding force reduction region R as reference points.

[0062] The overlapping wafer T, from which the peripheral portion We of the first wafer W has been removed, is then transported to the cleaning apparatus 70 via the wafer transport device 40. In the cleaning apparatus 70, the first wafer W and / or the second wafer S, after the peripheral portion We has been removed, are cleaned.

[0063] Afterwards, the overlapping wafer T, which has undergone all processing, is transferred via the transfer device 30 to the cassette C of the cassette stage 1 by the wafer transport device 20. In this way, a series of wafer processing steps in the wafer processing system 1 are completed.

[0064] According to the above embodiment, a bonding force reduction region R is formed in the bonding area between the bonding film Fw and the bonding film Fs. The peripheral portion We is removed using the first peripheral modification region N1 and the bonding force reduction region R as reference points. Therefore, no first wafer W remains radially outward from the first peripheral modification region N1 (peripheral portion We). Thus, it is unnecessary to remove the peripheral portion We in two stages as in the past, and in particular, it is unnecessary to use laser ablation for removal. As a result, edge trimming can be performed appropriately and efficiently.

[0065] In the above embodiments, in the modification apparatus 50, the first peripheral modification region N1 (first peripheral modification region M1) is formed after the second peripheral modification portion M2 is formed, but the formation order of the second peripheral modification portion M2 and the first peripheral modification region N1 is not limited to this. For example, the second peripheral modification portion M2 can be formed after the first peripheral modification region N1 is formed. In this case, by not connecting adjacent second peripheral modification portions M2 to each other, the above-mentioned edge trimming effect can also be enjoyed appropriately and efficiently.

[0066] In the above embodiments, the second peripheral modified portion M2 is formed radially outside the first peripheral modified region N1, but it can also be formed radially inside the first peripheral modified region N1. In this case, the bonding force reduction region R can also be formed to properly and efficiently remove the peripheral portion We.

[0067] However, the second peripheral modified portion M2 is formed near the surface Wa of the first wafer W. Therefore, for example, if the second peripheral modified portion M2 is formed above the thinning surface (pre-thinning surface) when the central portion Wc of the first wafer W is thinned, the second peripheral modified portion M2 may remain in the thinned central portion Wc of the first wafer W. Therefore, the second peripheral modified portion M2 is preferably formed radially outside the first peripheral modified region N1.

[0068] In the above embodiments, the first peripheral modified region N1 extends from the back surface Wb of the first wafer W to the bonding region of the bonding film Fw and the bonding film Fs, but it can also extend from the back surface Wb of the first wafer W to the bonding region (surface Wa) of the first wafer W and the bonding film Fw. The lower end position of the first peripheral modified region N1 depends on the adhesion force between the first wafer W and the bonding film Fw. When the first peripheral modified portion M1 is formed inside the first wafer W, the first peripheral modified portion M1 expands and experiences compressive stress. Moreover, for example, if the adhesion force between the first wafer W and the bonding film Fw is large, the compressive stress is transmitted to the bonding film Fw, and the first crack C1 extends to the bonding region of the bonding film Fw and the bonding film Fs. On the other hand, for example, if the adhesion force between the first wafer W and the bonding film Fw is small, the compressive stress remains inside the first wafer W, and the extension of the first crack C1 stops at the surface Wa of the first wafer W.

[0069] In the above embodiments, the bonding force reduction region R is formed at the bonding region between the bonding film Fw and the bonding film Fs, but it can also be formed at the bonding region (surface Wa) between the first wafer W and the bonding film Fw. The formation location of the bonding force reduction region R depends on the adhesion force between the first wafer W and the bonding film Fw. For example, if the adhesion force between the first wafer W and the bonding film Fw is large, the bonding force reduction region R is formed at the bonding region between the bonding film Fw and the bonding film Fs. On the other hand, if the adhesion force between the first wafer W and the bonding film Fw is small, the bonding force reduction region R is formed at the surface Wa of the first wafer W.

[0070] Regarding the formation direction of the first peripheral modified region N1, for example... Figure 9As shown, the first peripheral modification region N1 can also be formed in an inclined direction along the silicon crystal orientation of the first wafer W. For example, the silicon 111 crystal orientation is at about 70 degrees relative to the horizontal direction, but the first peripheral modification region N1 is formed along this 111 crystal orientation.

[0071] Here, when the blade B is inserted into the peripheral removal device 60 and the insertion force and insertion amount of the blade B are increased in order to properly remove the peripheral portion We, a crack may be generated from the radially inner front end of the second peripheral modification portion M2, causing the first wafer W and the second wafer S to peel off.

[0072] In this regard, when the first peripheral modification region N1 is formed along the crystal orientation as in this example, the peripheral portion We can be easily removed within this first peripheral modification region N1. As a result, the insertion force and insertion amount of the blade B during the removal of the peripheral portion We can be suppressed, thereby suppressing the aforementioned peeling.

[0073] In the above embodiments, the second peripheral modified portion M2 is formed in the plane direction of the first wafer W, but the formation direction of the second peripheral modified portion M2 is not limited to this. As described above, as long as adjacent second peripheral modified portions M2 are not connected to each other, for example, the second peripheral modified portion M2 may also be formed in an inclined direction from the plane direction of the first wafer W. In this case, the second peripheral modified portion M2 may, for example, be formed to descend from the radially inner side to the outer side.

[0074] In addition, such as Figure 9 As shown, the second peripheral modified portion M2 can also be stacked in multiple layers along the thickness direction of the first wafer W. In this case, cracks between adjacent second peripheral modified portions M2 can be prevented from connecting, and the tensile stress in the bonding force reduction region R can be increased. Furthermore, the upper and lower layers of the second peripheral modified portions M2 can be formed alternately in a way that they do not overlap when viewed from above. In this case, cracks can be further suppressed from connecting between adjacent second peripheral modified portions M2 in the thickness direction. Moreover, in the illustrated example, two layers of second peripheral modified portions M2 are formed, but the number of layers of second peripheral modified portions M2 is not limited to this.

[0075] In the above embodiments, a first peripheral modification region N1 (first peripheral modification part M1) and a second peripheral modification part M2 are formed in the modification device 50, but these first peripheral modification regions N1 and second peripheral modification parts M2 may also be formed by different modification devices.

[0076] In the above embodiments, a first peripheral modification region N1 and a second peripheral modification portion M2 are formed in the modification apparatus 50. However, multiple segmentation modification regions may also be formed as base points for segmenting the peripheral portion We to break it into fragments. Each segmentation modification region extends radially outward from the first peripheral modification region N1 along the thickness direction of the first wafer W. Specifically, a laser beam L is irradiated along the thickness direction of the first wafer W to form a segmentation modification portion, and cracks extend from the segmentation modification portion along the thickness direction of the first wafer W to form a segmentation modification region including these segmentation modification portions and cracks. By forming multiple segmentation modification regions radially, a row of segmentation modification regions extending radially outward from the first peripheral modification region N1 is formed, and multiple rows of single-row segmentation modification regions are formed circumferentially. In this case, when the peripheral portion We is processed in the peripheral removal apparatus 60, the peripheral portion We is segmented into multiple fragments based on the multiple rows of segmentation modification regions.

[0077] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The above embodiments can also be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit. For example, the constituent elements of the above embodiments can be arbitrarily combined. Such arbitrary combinations will naturally obtain the functions and effects of the various structural elements related to the combination, and other functions and effects known to those skilled in the art as described in this specification.

[0078] Furthermore, the effects described in this specification are merely illustrative or exemplary, and not limiting. That is, the technology disclosed herein can, together with or in lieu of the effects described above, achieve other effects known to those skilled in the art based on the description herein.

[0079] Explanation of reference numerals in the attached figures

[0080] 1: Wafer processing system; 50: Modification device; 60: Peripheral removal device; 80: Control device; M2: Second peripheral modification section; N1: First peripheral modification region; R: Bonding force reduction region; S: Second wafer; T: Overlapping wafer; W: First wafer; Wc: Central section; We: Peripheral section.

Claims

1. A substrate processing method for processing an overlapping substrate formed by bonding a first substrate and a second substrate, the substrate processing method comprising: A first peripheral modification region is formed inside the first substrate along the boundary between the peripheral portion and the central portion of the first substrate, which is the object to be removed; A second peripheral modification portion is formed radially outward from at least the first peripheral modification region, inside the first substrate; By forming the second peripheral modification portion, a bonding force reduction region is formed in the radially outer side of the first peripheral modification region and in the bonding region between the first substrate and the second substrate; as well as The peripheral portion is removed using the first peripheral modified region and the bonding force reduction region as reference points.

2. The substrate processing method according to claim 1, wherein, When forming the second peripheral modified portion, adjacent second peripheral modified portions are not connected to each other.

3. The substrate processing method according to claim 2, wherein, When forming the second peripheral modified portion, the minimum interval or intensity of the laser beam irradiated radially inside the first substrate is controlled.

4. The substrate processing method according to claim 1, wherein, The second peripheral modified portion is formed in a stacked manner in the thickness direction of the first substrate.

5. The substrate processing method according to claim 4, wherein, When the second peripheral modified portion is formed, the second peripheral modified portion of the upper layer and the second peripheral modified portion of the lower layer do not overlap when viewed from above.

6. The substrate processing method according to claim 1, wherein, The bonding force reduction region is formed in the bonding region between the first laminated film formed on the surface of the first substrate and the second laminated film formed on the surface of the second substrate.

7. The substrate processing method according to claim 6, wherein, The first peripheral modification region includes a first peripheral modification portion and a first crack extending from the first peripheral modification portion. The first peripheral modified region extends to the junction region between the first laminated film and the second laminated film.

8. The substrate processing method according to claim 1, wherein, The first peripheral modified region is connected to the region where the bonding force decreases. The area of ​​reduced bonding force is formed by peeling off the bonding area.

9. A substrate processing system for processing an overlapping substrate formed by bonding a first substrate and a second substrate, the substrate processing system comprising: A modification device that forms a first peripheral modification region inside the first substrate along the boundary between the peripheral portion and the central portion of the first substrate that is the object to be removed, and forms a second peripheral modification portion radially outward from at least the first peripheral modification region inside the first substrate. A peripheral removal device that removes the peripheral portion based on the first peripheral modification region and the region of decreased bonding force; as well as Control device, The control device performs the following control: by forming the second peripheral modification portion, a bonding force reduction region is formed in the radially outer side of the first peripheral modification region and in the bonding region between the first substrate and the second substrate, a bonding force reduction region is formed.

10. The substrate processing system according to claim 9, wherein, When forming the second peripheral modified portion, the control device performs control to prevent adjacent second peripheral modified portions from connecting with each other.

11. The substrate processing system according to claim 10, wherein, When forming the second peripheral modified portion, the control device controls at least the interval or intensity of the laser beam that is radially irradiated inside the first substrate.

12. The substrate processing system according to claim 9, wherein, The control device performs control over the formation of the second peripheral modified portion in the thickness direction of the first substrate.

13. The substrate processing system according to claim 12, wherein, When forming the second peripheral modified portion, the control device performs control to ensure that the second peripheral modified portion of the upper layer and the second peripheral modified portion of the lower layer do not overlap when viewed from above.

14. The substrate processing system according to claim 9, wherein, The control device performs control to form the bonding force reduction region in the bonding region between the first laminate formed on the surface of the first substrate and the second laminate formed on the surface of the second substrate.

15. The substrate processing system according to claim 14, wherein, The first peripheral modification region includes a first peripheral modification portion and a first crack extending from the first peripheral modification portion. The control device performs control to extend the first peripheral modified region to the junction region of the first laminated film and the second laminated film.

16. The substrate processing system according to claim 9, wherein, The control device performs the following controls: Connect the first peripheral modified region to the region with reduced bonding force; and The bonding region is peeled off to form the bonding force reduction region.

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