Substrate processing method and wafer processing system

Abstract

To detect whether an unbonded surface has been properly formed before removing a peripheral portion after irradiation of laser light when removing the peripheral portion from a substrate using the unbonded surface formed by the irradiation of the laser light as a base point.SOLUTION: A substrate processing method for removing a peripheral portion of a first substrate to be removed in an overlapped substrate in which the first substrate and a second substrate are bonded together includes: irradiating an interface between the first substrate and the second substrate at the peripheral portion with laser light to form an unbonded surface at the interface where the first substrate and the second substrate are peeled off; and detecting a peeled state at the unbonded surface, in which at the detection of the peeled state at the unbonded surface, a height of the first substrate or a difference between a first height position and a second height position that differ in a thickness direction of the overlapped substrate is detected.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a substrate processing system having a reforming layer forming device that forms a reforming layer inside a first substrate along the boundary between the peripheral portion and the central portion of the first substrate to be removed in a polymerized substrate in which the first substrate and the second substrate are joined, and a peripheral removal device that removes the peripheral portion of the first substrate with the reforming layer as a reference point.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure detects whether or not the unbonded surface is appropriately formed after irradiation with laser light and before removal of the peripheral portion when removing the peripheral portion from the substrate with the unbonded surface formed by irradiation with laser light as a reference point.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a substrate processing method for removing a peripheral portion of a first substrate to be removed in a polymerized substrate in which the first substrate and the second substrate are joined, the method including irradiating a laser beam onto an interface between the first substrate and the second substrate in the peripheral portion to form an unbonded surface formed by peeling between the first substrate and the second substrate at the interface, and detecting a peeling state at the unbonded surface, and when detecting the peeling state at the unbonded surface, detecting a height of the first substrate or a difference between a first height position and a second height position different in a thickness direction of the polymerized substrate. [Effects of the Invention]

[0006] According to this disclosure, when removing the peripheral portion from a substrate using an unbonded surface formed by laser irradiation as a starting point, it is possible to detect whether the unbonded surface is properly formed after laser irradiation but before the removal of the peripheral portion. [Brief explanation of the drawing]

[0007] [Figure 1] This is an explanatory diagram showing an example of the configuration of a polymerized wafer to be processed. [Figure 2] This is a plan view showing a schematic configuration of the wafer processing system according to this embodiment. [Figure 3] This is a plan view showing an example of the configuration of an inspection device. [Figure 4] This is a side view showing an example of the configuration of the inspection device. [Figure 5] This is an explanatory diagram showing the main steps of wafer processing according to this embodiment. [Figure 6] This is an explanatory diagram showing the main steps of wafer processing according to this embodiment. [Figure 7] This is an explanatory diagram showing an example of how a spectroscopic interferometer works. [Figure 8] This is an explanatory diagram showing the inspection locations of unbonded surfaces using a spectroscopic interferometer. [Figure 9] This is a plan view showing an example of the configuration of an unbonded surface forming apparatus. [Figure 10] This is a side view showing an example of the configuration of an unbonded surface forming apparatus. [Figure 11] This is an explanatory diagram showing the inspection of an unjoined surface according to another embodiment. [Modes for carrying out the invention]

[0008] In the semiconductor device manufacturing process, in a polymer substrate formed by joining a first substrate (a silicon substrate such as a semiconductor) on which multiple electronic circuits and other devices are formed on its surface with a second substrate, the peripheral edge of the first substrate may be removed, a process known as edge trimming.

[0009] Edge trimming of the first substrate is performed using, for example, a substrate processing system disclosed in Patent Document 1. Specifically, a modified layer is formed by irradiating the interior of the first substrate with laser light, and the peripheral portion is removed from the first substrate using the modified layer as a starting point. Furthermore, according to the substrate processing system described in Patent Document 1, the bonding force is reduced by irradiating the interface between the first substrate and the second substrate at the peripheral portion with laser light, thereby ensuring proper removal of the peripheral portion.

[0010] Incidentally, if the bonding force is not adequately reduced across the entire peripheral edge of the substrate to be removed by irradiating the interface with laser light, for example, if the bonding force is not reduced in a part of the circumferential direction, or if the width of the region formed to reduce the bonding force around the entire circumference is not uniform, a part of the peripheral edge of the first substrate to be removed may remain on the central side of the first substrate, which may cause the generation of particles or the like in subsequent processes.

[0011] The technology described herein has been made in view of the above circumstances, and when removing the peripheral portion from a substrate using an unbonded surface formed by irradiation with laser light as a starting point, it detects whether the unbonded surface is properly formed after irradiation with laser light and before removal of the peripheral portion. The wafer processing system as a substrate processing system and the wafer processing method as a substrate processing method according to this embodiment will be described with reference to the drawings. A wafer is an example of a substrate. In this specification, elements having substantially the same functional configuration are denoted by the same reference numerals to omit redundant explanations.

[0012] In the wafer processing system 1 described later according to this embodiment, processing is performed on a polymerized wafer T, which is a polymerized substrate formed by bonding a first wafer W as a first substrate and a second wafer S as a second substrate, as shown in Figure 1. Hereinafter, in the first wafer W, the side that is bonded to the second wafer S will be called the surface Wa, and the side opposite to surface Wa will be called the back surface Wb. Similarly, in the second wafer S, the side that is bonded to the first wafer W will be called the surface Sa, and the side opposite to surface Sa will be called the back surface Sb.

[0013] The first wafer W is a semiconductor wafer such as a silicon substrate, and a laser absorption layer P, a device layer Dw, and a bonding film Fw are laminated in this order on the surface Wa side. The laser absorption layer P absorbs the laser light irradiated by an unbonded surface forming device 50 described later. For example, an oxide film (SiO2 film) is used for the laser absorption layer P, but it is not particularly limited as long as it can absorb laser light. Note that the position of the laser absorption layer P is not limited to the illustrated example, and it may be formed, for example, between the device layer Dw and the bonding film Fw. The device layer Dw includes a plurality of devices. For the bonding film Fw, for example, an oxide film (THOX film, SiO2 film, TEOS film), a SiC film, a SiCN film, or an adhesive is used. Note that the peripheral edge We of the first wafer W is chamfered, and the thickness decreases toward the tip. The peripheral edge We is a portion to be removed by an edge trim described later, and is, for example, in the range of 0.5 mm to 3 mm in the radial direction from the outer end of the first wafer W.

[0014] In the following embodiments, the back surface Wb of the first wafer W is the surface on the side to be removed, and is the surface opposite to the bonding surface with the second wafer S.

[0015] The second wafer S is also a semiconductor wafer such as a silicon substrate, and a device layer Ds and a bonding film Fs are laminated in this order on the surface Sa side, and the peripheral edge is chamfered. The device layer Ds and the bonding film Fs are the same as the device layer Dw and the bonding film Fw of the first wafer W, respectively. The polymerized wafer T is formed by bonding the bonding film Fw of the first wafer W and the bonding film Fs of the second wafer S. Note that the second wafer S does not necessarily have to be a device wafer on which the device layer Ds is formed, and it may be, for example, a support wafer that supports the first wafer W.

[0016] As shown in FIG. 2, the wafer processing system 1 has a configuration in which the loading / unloading station 2 and the processing station 3 are integrally connected. In the loading / unloading station 2, for example, a hoop F capable of accommodating a plurality of polymerized wafers T is loaded / unloaded between the outside. The processing station 3 includes various processing apparatuses for performing desired processing on the polymerized wafers T.

[0017] The loading / unloading station 2 is provided with a hoop mounting table 10 on which a hoop F capable of accommodating a plurality of polymerized wafers T is placed. On the positive X-axis side of the hoop mounting table 10, a wafer transfer device 20 is provided adjacent to the hoop mounting table 10. The wafer transfer device 20 is configured to move on a transfer path 21 extending in the Y-axis direction and to be able to transfer the polymerized wafer T between the hoop F on the hoop mounting table 10 and a transition device 30 described later.

[0018] The loading / unloading station 2 is provided with a transition device 30 for transferring the polymerized wafer T between the wafer transfer device 20 and the processing station 3 adjacent to the wafer transfer device 20 on the positive X-axis side of the wafer transfer device 20.

[0019] The processing station 3 is arranged with a wafer transfer device 40, an unbonded surface forming device 50, an internal modification device 60, a peripheral removal device 70, and an inspection device 80.

[0020] 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 to be able to transfer the polymerized wafer T to the transition device 30, the unbonded surface forming device 50, the internal modification device 60, the peripheral removal device 70, and the inspection device 80 in the loading / unloading station 2.

[0021] The unbonded surface formation apparatus 50 irradiates a laser absorption layer P formed on the interface between the first wafer W and the second wafer S (in this embodiment, the surface Wa of the first wafer W) with laser light (for example, a CO2 laser) to form an unbonded surface R (see Figure 5 below) where delamination occurs at the interface between the first wafer W and the second wafer S (in this embodiment, between the first wafer W and the laser absorption layer P). In the following description, this unbonded surface R formed by the delamination of the first wafer W and the second wafer S may be referred to as the space between the first wafer W and the second wafer S (hereinafter simply referred to as "space"). The configuration of the unbonded surface formation apparatus 50 can be arbitrarily determined. The unbonded surface formation apparatus 50 has a control device 51, which will be described later.

[0022] The internal modification apparatus 60 irradiates the interior of the first wafer W with laser light (e.g., a YAG laser or fiber laser) to form a peripheral modification layer M1 (see Figure 6 below), which serves as a starting point for separating the peripheral region We. The configuration of the internal modification apparatus 60 can be arbitrarily determined. The internal modification apparatus 60 has a control device 61, which will be described later.

[0023] The edge removal device 70 removes the peripheral portion We of the first wafer W, i.e., edge trims, using the peripheral modified layer M1 formed by the internal modification device 60 as a starting point. The edge trimming method can be arbitrarily selected. 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.

[0024] The inspection device 80 inspects whether an unbonded surface R has been properly formed at the interface between the first wafer W and the second wafer S in the unbonded surface formation device 50.

[0025] As shown in Figures 3 and 4, the inspection apparatus 80 has a chuck 100 that holds the polymerized wafer T on its upper surface. In one example, the chuck 100 holds the back surface Sb of the second wafer S by suction when the first wafer W is positioned on the upper side and the second wafer S is positioned on the lower side. The chuck 100 is supported by a slider table 102 via an air bearing 101. A rotating mechanism 103 is provided on the lower side of the slider table 102. The rotating mechanism 103 incorporates, for example, a motor as a drive source. The chuck 100 is configured to rotate freely around a vertical axis via the air bearing 101 by the rotating mechanism 103. The slider table 102 is configured to move freely on a rail 106 that extends in the Y-axis direction on a base 105 via a moving mechanism 104 provided on its lower side. The drive source for the moving mechanism 104 is not particularly limited, but for example, a linear motor can be used.

[0026] Above the chuck 100, a spectroscopic interferometer 110 is provided for detecting the unbonded surface R (space) formed on the polymerized wafer T held by the chuck 100. The spectroscopic interferometer 110 has a head 111 and an analysis unit 112.

[0027] The head 111 includes an irradiation unit (not shown) that irradiates the polymerized wafer T on the chuck 100 with measurement light, and a spectroscopic unit (not shown) that detects interference between measurement light (reflected light) reflected at different height positions of the polymerized wafer T (first height position H1 and second height position H2: see Figure 5 later). The measurement light irradiated from the irradiation unit is arbitrarily selected to be light that is transparent to the first wafer W (silicon).

[0028] The analysis unit 112 calculates the distance between the first height position H1 and the second height position H2 by detecting the interference between the reflected light from the first height position H1 and the second height position H2, respectively, which are detected by the head 111. The analysis unit 112 may be incorporated into the control device 90 described later. In other words, the distance between the first height position H1 and the second height position H2 may be calculated by the control device 90 described later instead of the inspection device 80.

[0029] The wafer processing system 1 described above is equipped with control devices 51, 61, and 90. Control device 51 individually controls the operation of the unbonded surface forming apparatus 50. Control device 61 individually controls the operation of the internal modification apparatus 60. Control device 90 oversees the control of a series of wafer processing operations in the wafer processing system 1. Control devices 51, 61, and 90 are computers equipped with, for example, a CPU and memory, and have a program storage unit (not shown). The program storage unit stores a program that controls the processing of the polymerized wafer T. The program may have been recorded on a storage medium H readable by the computer and may have been installed from said storage medium H. Furthermore, the storage medium H may be temporary or permanent.

[0030] In this embodiment, control devices 51 and 61 are installed separately for the unbonded surface forming device 50 and the internal modification device 60, respectively. However, these control devices 51 and 61 may be configured as an integral part of the control device 90. In other words, the operation of the unbonded surface forming device 50 and the internal modification device 60 may be controlled by the control device 90.

[0031] Next, a wafer processing procedure performed using the wafer processing system 1 configured as described above will be explained. In this embodiment, a first wafer W and a second wafer S are bonded together to form a polymerized wafer T in advance.

[0032] First, a hoop F containing multiple polymerized wafers T is placed on the hoop mounting table 10 of the loading / unloading station 2. Next, the polymerized wafers T inside the hoop F are removed by the wafer transport device 20 and transported to the unbonded surface forming device 50 via the transition device 30 and the wafer transport device 40.

[0033] In the unbonded surface formation apparatus 50, as shown in Figure 5(a), laser light L1 is irradiated onto the laser absorption layer P formed on the surface Wa of the first wafer W. When the laser light L1 is irradiated, the thermal stress generated by the irradiation of the laser light causes delamination at the interface between the first wafer W and the second wafer S where the adhesion force is weak (in this embodiment, the interface between the first wafer W and the laser absorption layer P), thereby forming an unbonded surface R in which the bonding force between the first wafer W and the second wafer S is reduced.

[0034] The polymerized wafer T on which the unbonded surface R has been formed is then transported to the inspection device 80 by the wafer transport device 40. The inspection device 80 performs an inspection to determine whether the unbonded surface R has been properly formed in the unbonded surface forming device 50.

[0035] In the inspection device 80, the polymerized wafer T held in the chuck 100 is moved to an inspection position below the spectroscopic interferometer 110. At the inspection position, while rotating the chuck 100, measurement light L2 from the irradiation part of the head 111 is irradiated toward the polymerized wafer T, as shown in Figure 5(b). Then, reflected light L2a and L2b from two different height positions H1 and H2 of the polymerized wafer T are brought into the spectroscopic unit. The spectroscopic unit detects the interference (reflection spectrum) of the reflected light L2a and L2b shown in Figure 7, and based on this, the analysis unit 112 calculates the thickness t, which is the distance between the upper and lower surfaces of the unbonded surface R (space). The calculated thickness t of the unbonded surface R (space) is output to the control device 90. In this embodiment, the first height position H1 is the surface on the first wafer W side of the interface between the first wafer W and the laser absorption layer P. The second height position H2 is the interface between the first wafer W and the laser absorption layer P, specifically the side facing the laser absorption layer P (the second wafer S).

[0036] The control device 90 determines whether an unbonded surface R has been properly formed on the polymerized wafer T based on the output thickness t. The determination of the unbonded surface R can be performed by any method.

[0037] In one example, the determination of an unbonded surface R can be performed by comparing the measurement result after the formation of the unbonded surface R in the inspection device 80 with a preset first threshold. When the measurement result exceeds the preset first threshold, it is determined that an unbonded surface R has been formed. The first threshold used for comparison may be obtained, for example, by measuring the same polymerized wafer T that is the target of unbonded surface R formation in the inspection device 80 before the formation of the unbonded surface R in the unbonded surface forming device 50. That is, the first threshold may be obtained by comparing the measurement result in a state where an unbonded surface R has not been formed (no delamination has occurred) with the state where an unbonded surface R has been formed (delamination has occurred). Alternatively, the first threshold may be obtained in advance from a different wafer (e.g., a dummy wafer). That is, the first threshold may be obtained by comparing the measurement result on a different wafer (ideal state) where an unbonded surface R has been properly formed with the measurement result on an actual wafer where an unbonded surface R has been formed.

[0038] Furthermore, the calculated thickness t of the unjointed surface R (space) can be used as the measurement result for comparison with the first threshold. In this case, the first threshold is the value at which it is determined that an unjointed surface R has been formed, and is a value greater than t > 0, which is the thickness at which it is determined that an unjointed surface R (space) has been formed. The first threshold used for comparison may be set to a value greater than 0.

[0039] The control device 90 then determines that the unabonded surface R is properly formed and that a predetermined second threshold is met, and determines that the peripheral edge We of the first wafer W can be properly separated from the second wafer S. The second threshold is set to a value that allows the peripheral edge We of the first wafer W to be properly separated from the second wafer S in the subsequent edge trimming by the peripheral edge removal device 70. The second threshold is set, for example, by prior experiments or simulations. Possible values ​​used as the second threshold include the area ratio of the region where the unabonded surface R is formed to the total area of ​​the inspection surface at the peripheral edge We, and the width of the unabonded surface R.

[0040] In this embodiment, by detecting the occurrence of spaces constituting the unjointed surface R using the spectroscopic interferometer 110, it is possible to detect whether or not the unjointed surface R is properly formed.

[0041] Furthermore, it is desirable that the detection of the reflection spectrum by the inspection device 80 be performed over the entire surface (all around: see Figure 8(a)) of the unbonded surface R formed on the polymerized wafer T. However, in order to shorten the time required for inspection and improve throughput, the unbonded surface R formed around the entire circumference of the peripheral We may be thinned out in the circumferential direction and the inspection may be performed at multiple points (for example, 4 points every 90 degrees: see Figure 8(b)). Moreover, for example, the unbonded surface R is formed by irradiating the peripheral We with laser light L in multiple radial directions (8 times in the example of Figure 8). For this reason, the unbonded surface R may be thinned out in the radial direction (for example, the portion irradiated by 5 laser beams L in the radial direction: see Figure 8(c)) and the inspection may be performed over the entire circumference of the unbonded surface R.

[0042] If it is determined that the unbonded surface R is not properly formed, that is, for example, if it is determined that the unbonded surface R in a part of the peripheral area We does not meet the preset first or second threshold, or if it is determined that the width of the unbonded surface R is not uniform, the wafer transport device 40 will remove the polymerized wafer T from the inspection device 80 and load the next polymerized wafer T into the inspection device 80. The polymerized wafer T removed from the inspection device 80 will be processed again or recovered, for example.

[0043] Meanwhile, polymerized wafers T in which the unbonded surface R is determined to be properly formed are then transported to the internal modification apparatus 60 by the wafer transport apparatus 40.

[0044] In the internal modification apparatus 60, the laser beam L3 is irradiated to a predetermined irradiation position, and as shown in Figure 6(a), a peripheral modification layer M1 is formed inside the first wafer W. The peripheral modification layer M1 serves as the starting point for removing the peripheral portion We in the edge trimming described later.

[0045] The polymerized wafer T, in which a peripheral modification layer M1 has been formed inside the first wafer W, is then transported to the peripheral removal device 70 by the wafer transport device 40.

[0046] In the peripheral removal apparatus 70, as shown in Figure 6(b), the peripheral portion We of the first wafer W is removed, i.e., edge trimming is performed. At this time, the peripheral portion We is separated from the central portion of the first wafer W (radially inward from the peripheral portion We) with the peripheral modification layer M1 as the starting point.

[0047] Subsequently, the polymerized wafer T, after all processing has been completed, is transported to the transition device 30 by the wafer transport device 40, and then to the hoop F of the hoop mounting table 10 by the wafer transport device 20. In this way, the series of wafer processing in the wafer processing system 1 is completed. The polymerized wafer T, after edge trimming by the peripheral removal device 70, may be cleaned in a cleaning device (not shown) prior to being transported to the hoop F on the hoop mounting table 10.

[0048] As described above, according to the wafer processing method of this embodiment, the inspection apparatus 80 uses a spectroscopic interferometer 110 to detect the thickness t of the unbonded surface R (space) formed inside the polymerized wafer T, thereby determining whether or not the unbonded surface R has been properly formed.

[0049] In the above embodiment, the unbonded surface forming apparatus 50 and the inspection apparatus 80 were arranged independently in the wafer processing system 1, but the unbonded surface forming apparatus 50 and the inspection apparatus 80 may be configured as a single unit. Hereinafter, the configuration of the unbonded surface forming apparatus 150 according to the second embodiment, in which the configurations corresponding to the unbonded surface forming apparatus 50 and the inspection apparatus 80 in the above embodiment are configured as a single unit, will be described with reference to the drawings. In the following description, elements having substantially the same functional configuration as the unbonded surface forming apparatus 50 or inspection apparatus 80 according to the first embodiment described above will be denoted by the same reference numerals to avoid redundant explanations.

[0050] As shown in Figures 9 and 10, the unbonded surface forming apparatus 150 according to the second embodiment has, in addition to the configuration of the inspection apparatus 80 shown in Figure 4, a laser irradiation unit that irradiates the polymerized wafer T with laser light L1 to form an unbonded surface R. The configuration of the chuck 100 and the spectroscopic interferometer 110 is the same as that of the inspection apparatus 80 described above.

[0051] In this embodiment, a laser head 160 is provided on the negative Y-axis side of the spectroscopic interferometer 110 above the chuck 100. The laser head 160 has a lens 161. The lens 161 is provided on the lower surface of the laser head 160 and irradiates the inside of the polymerized wafer T held by the chuck 100, more specifically the laser absorption layer P formed on the surface Wa of the first wafer W, with laser light L1. This causes delamination at the interface between the laser absorption layer P and the first wafer W, forming an unbonded surface R in which the bonding force between the first wafer W and the second wafer S is reduced. In the technology according to this disclosure, the laser head 160 and the lens 161 together are sometimes referred to as the "laser irradiation unit".

[0052] The unbonded surface formation apparatus 150 according to the second embodiment is configured as described above. The unbonded surface formation apparatus 150 can continuously perform the formation of an unbonded surface R on the polymerized wafer T by the laser irradiation unit and the inspection of the unbonded surface R by the spectroscopic interferometer 110.

[0053] Furthermore, by integrating the laser irradiation unit and the spectroscopic interferometer 110 into a single device, the time from the formation of the unbonded surface R to inspection can be shortened (in-line), improving throughput. In addition, by integrating the laser irradiation unit and the spectroscopic interferometer 110 into a single device, the number of devices arranged in the wafer processing system 1 can be reduced, making the wafer processing system 1 smaller and reducing its footprint.

[0054] The inspection of the unbonded surface R using the unbonded surface forming device 150 may be performed continuously by moving the chuck 100 below the spectroscopic interferometer 110 after the formation of the unbonded surface R by the laser irradiation unit. However, the unbonded surface forming device 150 may be configured to perform the formation of the unbonded surface R by the laser irradiation unit and the inspection by the spectroscopic interferometer 110 simultaneously.

[0055] In this case, for example, the lens 161 of the laser irradiation unit and the head 111 of the spectroscopic interferometer 110 may be positioned close together in the Y-axis direction so that both are located above the polymerized wafer T held in the chuck 100 in a plan view, or the lens 161 and the head 111 may be configured as a single unit.

[0056] In this way, for example, by performing an inspection with the spectroscopic interferometer 110 to follow up on the formation of the unbonded surface R by the laser irradiation unit, and by performing the formation of the unbonded surface R by the laser irradiation unit and the inspection with the spectroscopic interferometer 110 simultaneously, the throughput of the unbonded surface formation device 150 can be further improved.

[0057] In the above embodiments, the formation state of the unbonded surface R (the delamination state between the first wafer W and the second wafer S) formed in the unbonded surface forming apparatus was detected to determine whether the unbonded surface R was properly formed. However, the inspection method for the unbonded surface R is not limited to this.

[0058] Specifically, in an unbonded surface forming apparatus, a polymerized wafer T in which an unbonded surface R is formed on the peripheral We will have a height of the back surface Wb at the peripheral We that is higher than the height of the back surface Wb at the central part (radially inward from the peripheral We) where the unbonded surface R is not formed, due to the delamination of the laser absorption layer P and the first wafer W, as shown in Figure 11.

[0059] Therefore, when determining whether the unjointed surface R has been properly formed, the height of the back surface Wb at this peripheral area We may be measured. Specifically, for example, an optical flat (reference horizontal plane) of a different height from the back surface Wb of the first wafer W may be provided in the spectroscopic interferometer 110, and the interference (reflection spectrum) of the reflected light from the optical flat as the first height position and the reflected light from the height of the first wafer W (for example, the back surface Wb of the first wafer W at the peripheral We) as the second height position may be detected. In this case, the difference between the first height and the second height before and after the formation of the unbonded surface R is calculated, and if this difference has changed before and after the formation of the unbonded surface R, it can be determined that the unbonded surface R has been properly formed. Alternatively, instead of an optical flat, the back surface Wb at the center of the first wafer W, which is the first height position, may be set as the reference horizontal plane, and the interference (reflection spectrum) between the reflected light from the back surface Wb and the reflected light from the back surface Wb at the peripheral edge We of the first wafer W, which is the second height position, may be detected. In this case, before the formation of the unbonded surface R, the height of the back surface Wb is the same at the center and peripheral edge We of the first wafer W, but after the formation of the unbonded surface R, the height of the back surface Wb is different at the center and peripheral edge We of the first wafer W. By detecting that at least the detected height of the back surface Wb at the peripheral edge We is higher than the height of the back surface Wb at the center (reference horizontal plane), it can be determined that the unbonded surface R has been properly formed.

[0060] Furthermore, when measuring the height of the back surface Wb of the first wafer W in this manner, instead of the thickness t of the unbonded surface R, which was used as a measurement result for comparison with the first threshold in the above embodiment, the difference in height t2 of the back surface Wb between the central part and the peripheral part We (see Figure 11) can be used as a measurement result for comparison with the first threshold.

[0061] Furthermore, for example, a displacement sensor (not shown) may be provided above the chuck 100 in place of or in addition to the spectrophotometer 110, and the distance from the displacement sensor to the back surface Wb of the first wafer W may be measured at both the central and peripheral parts We of the first wafer W. In other words, the unbonded surface R may be detected by detecting the difference t2 (see Figure 11) in the height position between the central and peripheral parts We of the first wafer W. In this case, the inspection apparatus can be configured simply by changing the spectrophotometer 110 to a displacement sensor (not shown) in the configuration of the inspection apparatus 80 shown in Figure 4.

[0062] As described above, the unbonded surface R occurs in areas with weak adhesion at the interface between the first wafer W and the second wafer S. However, by inspecting the unbonded surface R at the height of the back surface Wb of the first wafer W, it is possible to determine whether the unbonded surface R (delamination between the first wafer W and the second wafer S) has been properly formed, even if it occurs in a layer below the device layer Dw (for example, at the interface between the bonding film Fw and the bonding film Fs).

[0063] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the functions and effects of each constituent element in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description herein. Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that will be apparent to those skilled in the art from the description herein, in addition to or in lieu of the effects described herein. [Explanation of symbols]

[0064] 1. Wafer Processing System 50 Unbonded surface forming device 80 Inspection equipment H1 First height position H2 Second height position L1 laser light R Unbonded surface S Second wafer T Polymerized wafer W First wafer We Peripheral area

Claims

1. A substrate processing method for removing the peripheral edge of a first substrate to be removed in a polymer substrate in which a first substrate and a second substrate are joined, comprising: irradiating the interface between the first substrate and the second substrate at the peripheral edge with laser light to form an unjointed surface formed by the delamination of the first substrate and the second substrate at the interface; and detecting the delamination state at the unjointed surface, wherein, when detecting the delamination state at the unjointed surface, the height of the first substrate, or the difference between a first height position and a second height position that are different in the thickness direction of the polymer substrate, is detected.

2. The substrate processing method according to claim 1, wherein the first height position is the height position of the upper surface on the first substrate side of the unbonded surface, and the second height position is the height position of the lower surface on the second substrate side of the unbonded surface.

3. The substrate processing method according to claim 1, wherein the height of the first substrate is the height position of the surface opposite to the surface on the bonding side with the second substrate at the peripheral edge of the first substrate, and when detecting the delamination state at the unbonded surface, it is detected that the detected height of the first substrate is higher than a preset reference horizontal plane or greater than a preset threshold.

4. The substrate processing method according to claim 1, wherein the height of the first substrate is the height position of the surface opposite to the surface on the bonding side with the second substrate at the peripheral edge of the first substrate, and when detecting the delamination state at the unbonded surface, it is detected that the height of the first substrate is at least higher than the height of the opposite surface at the central part of the first substrate.

5. The substrate processing method according to any one of claims 1 to 4, wherein, in detecting the peeling state of the unbonded surface, the height of the first substrate, or the first height position and the second height position are detected before the formation of the unbonded surface and after the formation of the unbonded surface, and the height of the first substrate, or the difference between the first height position and the second height position before and after the formation of the unbonded surface is compared.

6. The substrate processing method according to any one of claims 1 to 4, wherein, when detecting the unbonded surface, the height of the first substrate, or the first height position and the second height position are detected after the formation of the unbonded surface, and the height of the first substrate, or the difference between the first height position and the second height position is compared with the difference in a reference substrate different from the polymerized substrate on which the unbonded surface is to be formed.

7. A substrate processing system for removing the peripheral edge of a first substrate to be removed in a polymerized substrate in which a first substrate and a second substrate are joined, comprising: an unbonded surface forming device that irradiates laser light onto the interface between the first substrate and the second substrate at the peripheral edge to form an unbonded surface between the first substrate and the second substrate at the interface; and an inspection device that detects the peeling state of the unbonded surface, wherein the inspection device detects the height of the first substrate, or different first and second height positions, in the thickness direction of the polymerized substrate.

8. The substrate processing system according to claim 7, wherein the first height position is the height position of the upper surface on the first substrate side of the unbonded surface, and the second height position is the height position of the lower surface on the second substrate side of the unbonded surface, and the inspection device detects the difference between the first height position and the second height position.

9. The inspection device has an optical flat that serves as a reference horizontal plane, The height of the first substrate is the height position of the surface opposite to the surface on the bonding side with the second substrate at the peripheral edge of the first substrate, The substrate processing system according to claim 7, wherein the inspection device detects that the height of the first substrate is higher than the reference horizontal plane or greater than a preset threshold.

10. The substrate processing system according to claim 7, wherein the height of the first substrate is the height position of the surface opposite to the surface on the bonding side with the second substrate at the peripheral edge of the first substrate, and the inspection device detects, when detecting the delamination state of the unbonded surface, that the height of the first substrate is at least higher than the height of the opposite surface at the central part of the first substrate.

11. The substrate processing system according to any one of claims 7 to 10, wherein the inspection device comprises a spectroscopic interferometer.

12. The substrate processing system according to claim 10, wherein the inspection device has a displacement meter.

13. The inspection device detects the height of the first substrate, or the first height position and the second height position, before the formation of the unbonded surface and after the formation of the unbonded surface. A substrate processing system according to any one of claims 7 to 9, comprising comparing the height of the first substrate before and after the formation of the unbonded surface, or the difference between the first height position and the second height position.

14. The substrate processing system according to any one of claims 7 to 9, wherein the inspection device detects the height of the first substrate, or the first height position and the second height position, after the formation of the unbonded surface, and compares the height of the first substrate, or the difference between the first height position and the second height position, with the difference in a reference substrate different from the polymerized substrate on which the unbonded surface is to be formed.

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