Substrate processing method

Abstract

An objective of the present invention is to suppress substrate chipping and / or cracking when a stacked substrate is being thinned.　This substrate processing method includes: a step for forming a groove in a first surface of a substrate, in an edge portion of the substrate along a boundary between the edge portion and a central portion inward of the edge portion; a step for bonding the first surface of the substrate in which the groove has been formed to a supporting body; and a step for thinning the substrate by grinding a second surface of the substrate on the opposite side to the first surface, and separating the central portion and the edge portion of the substrate by means of the groove in a state in which both the central portion and the edge portion of the substrate have been bonded to the supporting body.

Description

Substrate processing method

[0005]

[0001] This application relates to a substrate processing method.

[0002] In recent years, in order to achieve further high density and high functionality of semiconductor devices, the development of three-dimensional packaging technology for stacking multiple substrates and integrating them three-dimensionally has been progressing. In three-dimensional packaging technology, for example, the device surface of a first substrate on which an integrated circuit and electrical wiring are formed is joined to the device surface of a second substrate on which an integrated circuit and electrical wiring are also formed. Further, after joining the first substrate to the second substrate, the second substrate is thinned by a polishing device or a grinding device. In this way, integrated circuits can be stacked in a direction perpendicular to the device surfaces of the first substrate and the second substrate.

[0003] In three-dimensional packaging technology, three or more substrates may be joined. For example, after thinning the second substrate joined to the first substrate, a third substrate may be joined to the second substrate and the third substrate may be thinned. In this specification, the form of a plurality of substrates joined to each other may be referred to as a "stacked substrate".

[0004] Usually, the outer peripheral surface of a substrate is pre-polished into a rounded shape in order to prevent cracking and chipping. When a second substrate having such a rounded outer peripheral surface is ground for thinning, as a result, sharp edges are formed on the second substrate. Such sharp edges (hereinafter referred to as knife edge portions) are formed by the back surface of the ground second substrate and the outer peripheral surface of the second substrate. Such knife edge portions are likely to cause chipping and / or cracking in the final stage of the grinding process, and there is also a risk that the contour of the second substrate deviates from the desired contour due to chipping, the cross section of the chipped portion of the second substrate becomes an irregular uneven shape, or cracks reach the device region. Further, when chipping and / or cracking occur, there is a risk of hindering the conveyance of the stacked substrate.

[0005] To prevent chipping and cracking during substrate grinding, for example, in the method described in Japanese Patent Application Publication No. 2003-143077 (Patent Document 1) (post-trim method), after joining the first substrate and the second substrate, a modified layer is formed by laser, discretely arranged in the thickness direction of the edge portion of the first substrate. After physically / mechanically removing the edge portion using the modified layer as a starting point, the first substrate is thinned by grinding.

[0006] Japanese Patent Publication No. 2003-143077

[0007] The method described in Patent Document 1 involves forming a modified layer on a substrate with a laser and removing the edges. As a result, cleavage occurs in areas where the modified layer is not present, particularly on the surface, which may cause cracks and / or particles to be generated in the substrate.

[0008] The present invention aims to solve at least some of the problems described above. One of the objectives of the present invention is to suppress chipping and / or cracking of a substrate when the substrate is thinned.

[0009] According to one aspect of the present invention, a substrate processing method is provided, comprising the steps of: forming a groove on a first surface of a substrate along the boundary between the edge portion of the substrate and the central portion inside the edge portion; joining the first surface of the substrate with the groove formed thereon to a support; and thinning the substrate by grinding the second surface opposite to the first surface of the substrate, and separating the central portion and the edge portion of the substrate by the groove while both the central portion and the edge portion of the substrate are joined to the support. The depth of the groove is less than the thickness of the substrate.

[0010] According to one aspect of the present invention, a substrate processing method is provided, which includes the steps of: joining a first surface of a substrate to a support; cutting the substrate by forming a groove that penetrates the substrate in the edge portion along the boundary between the edge portion and the central portion inside the edge portion on the second surface of the substrate opposite to the first surface of the substrate; and thinning the substrate by grinding the second surface of the substrate while both the central portion and the edge portion of the cut substrate are joined to the support.

[0011] This is a schematic diagram illustrating the manufacturing method of a laminated substrate according to the first embodiment. This is a schematic diagram illustrating the manufacturing method of a laminated substrate according to the first embodiment. This is a schematic diagram illustrating the manufacturing method of a laminated substrate according to the first embodiment. This is a schematic diagram illustrating the manufacturing method of a laminated substrate according to the first embodiment. This is an explanatory diagram illustrating the principle of suppressing chipping of the substrate in a laminated substrate. This is an explanatory diagram illustrating the principle of suppressing chipping of the substrate in a laminated substrate. This is an explanatory diagram illustrating the method of removing the edge portion. This is an explanatory diagram illustrating the method of removing the edge portion. This is an explanatory diagram illustrating the method of removing the edge portion. This is a flowchart illustrating the manufacturing method of a laminated substrate according to the first embodiment. This is a flowchart illustrating the manufacturing method of a laminated substrate according to the first embodiment. This shows the manufacturing method of a laminated substrate according to the second embodiment. This is a schematic diagram illustrating the manufacturing method of a laminated substrate according to the second embodiment. This is a schematic diagram illustrating the manufacturing method of a laminated substrate according to the second embodiment. This is a schematic diagram illustrating the manufacturing method of a laminated substrate according to the second embodiment. This is an explanatory diagram illustrating the principle of suppressing chipping of the substrate in a laminated substrate. This is an explanatory diagram illustrating the method of removing the edge portion. This is a flowchart illustrating the manufacturing method of a laminated substrate according to the second embodiment. This is a schematic diagram illustrating the configuration of a water laser device. This is a schematic diagram illustrating the configuration of a water laser device. This is a cross-sectional view of the nozzle assembly of a water laser device. This is an enlarged view of the water jet flow and laser beam. This is an explanatory diagram illustrating the control principle of processing depth using a water laser device. This is an explanatory diagram illustrating the control principle of processing width using a water laser device. This is an explanatory diagram illustrating a substrate thinning method related to related technologies. This is an explanatory diagram illustrating debris that may be generated on the substrate during groove processing. This is an example of a flowchart for a laminated substrate manufacturing method, including debris removal.

[0012] Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are schematic in order to facilitate understanding of the features, and the dimensional ratios of each component may not be the same as those of the actual components.

[0013] <First Embodiment> (Manufacturing Method Example 1) Figure 1A is a schematic diagram illustrating an example of a manufacturing method for a laminated substrate according to the first embodiment. In Figure 1A, the substrate W1 includes an edge portion Ew1 and a central portion Cw1 inside the edge portion Ew1, along the radial direction of the substrate W1. The substrate W1 also has a first surface (hereinafter also referred to as the front surface) and a second surface (hereinafter also referred to as the back surface) opposite the first surface. The substrate W1 includes a device region Dw1 in the central portion Cw1 of the front surface, on which a semiconductor device, MEMS, etc., is formed. In the example shown in Figure 1A, the central portion Cw1 and the device region Dw1 are shown to coincide on the front surface of the substrate W1, but the device region Dw1 may be smaller than the central portion Cw1 (there may be a predetermined margin between the device region Dw1 and the groove 10). The substrate W1 is, for example, a semiconductor wafer.

[0014] Similarly, the substrate W2 includes an edge portion Ew2 and a central portion Cw2 inside the edge portion Ew2, along the radial direction of the substrate W2. The substrate W2 also has a first surface (hereinafter referred to as the front surface) and a second surface (hereinafter also referred to as the back surface) opposite the first surface. The substrate W2 includes a device region Dw2 in the central portion Cw2 of the front surface, on which semiconductor devices, MEMS, etc., are formed. Here, we will explain assuming that the central portion Cw2 and the device region Dw2 coincide on the front surface of the substrate W2, but the device region Dw2 may be smaller than the central portion Cw2. The substrate W2 is, for example, a semiconductor wafer.

[0015] In step (a) of Figure 1A, a groove 10 is formed on the front surface of the substrate W1, along the boundary between the edge portion Ew1 and the central portion Cw1, and extending around the entire circumference of the substrate W1. The groove 10 can be formed, for example, by rotating the substrate W1 and irradiating the front surface of the substrate W1 with laser light using a water jet laser device (also referred to as a water laser device; described later). The depth of the groove 10 is, for example, 10 times or less the thickness of the substrate W1 after thinning. The width of the groove 10 is, for example, several tens of micrometers.

[0016] In step (b) of Figure 1A, substrate W1 is bonded to substrate W2 (wafer bonding). At this time, the front surface of substrate W1 and the front surface of substrate W2 are brought into contact and bonded. That is, the device area Dw1 of substrate W1 and the device area Dw2 of substrate W2 are brought into contact and bonded. The bonded substrates W1 and W2 are also referred to as a laminate or laminated substrate. This wafer bonding can be performed using adhesive bonding, anodic bonding, or any other bonding method.

[0017] In step (c) of Figure 1A, the back surface of the substrate W1 of the laminated substrate after wafer bonding is ground with a grinding device (grinder) 20 to thin the substrate W1. In this step, the back surface of the substrate W1 is thinned beyond the bottom surface of the groove 10 to a position closer to the front surface of the substrate W1 (the surface of the device area Dw1) than the bottom surface of the groove 10. That is, the back surface of the substrate W1 is ground / thinned until the opening of the groove 10 is exposed on the back surface of the substrate W1 and the central part Cw1 and the edge part Ew1 are separated by the groove 10. In this step, by thinning the back surface of the substrate W1 of the laminated substrate after wafer bonding, the central part Cw1 and the edge part Ew1 of the substrate W1 are separated by the groove 10 while both the central part Cw1 and the edge part Ew1 of the substrate W1 are bonded to the substrate W2.

[0018] When thinning the substrate W1, both the central portion Cw1 and the edge portion Ew1 are bonded to the substrate W2, which suppresses or prevents chipping of the edge portion Ew1 and the resulting cracks in the central portion Cw1. Compared to conventional methods that require forming a deeper trim to remove the substrate layer affected by chipping, the depth of the groove 10 formed in the substrate W1 can be reduced. This reduces the processing time for the groove.

[0019] In step (d) of Figure 1A, the edge portion Ew1 of substrate W1 is removed from the laminated substrate (W1, W2) using a grinding wheel 30 or the like. After that, the semiconductor process is continued on the laminated substrate.

[0020] In the example shown in Figure 1A, the grooves 10 are formed vertically, perpendicular to the surfaces (front and back) of the substrate W1. However, as shown in Figure 1B, the grooves 10 may be formed at an angle to the surfaces of the substrate W1. Except for the fact that the grooves 10 are formed at an angle, the manufacturing method is the same as in the example shown in Figure 1A. Similarly, in the manufacturing method examples described below, the grooves 10 may be formed perpendicular to the surfaces of the substrate W1, or at an angle to the surfaces of the substrate W1.

[0021] (Manufacturing Method Example 2) Figures 2A and 2B are schematic diagrams illustrating yet another example of the manufacturing method of a laminated substrate according to the first embodiment.

[0022] In step (a) of Figure 2A, substrates W1 and W2 that have undergone the semiconductor process are prepared. Substrates W1 and W2 are the same as those described above in Figure 1A. For the sake of explanation, it is explained here that substrates W1 and W2 are prepared in step (a), but substrate W2 only needs to be prepared by the time of the bonding step with substrate W1.

[0023] In step (b) of Figure 2A, a groove 10 is formed on the front surface of the substrate W1, along the boundary between the edge portion Ew1 and the central portion Cw1, extending around the entire circumference of the substrate, in the same manner as in step (a) of Figure 1A.

[0024] In step (c) of Figure 2A, the front surface of the substrate W1 is polished and flattened using a polishing device (for example, a CMP device). This is done to flatten the front surface of the substrate W1 after groove processing before bonding the substrate W1 to the substrate W2. At this time, since the central part Cw1 and the edge part Ew1 of the substrate W1 have the same thickness, deterioration of the edge profile at the edge of the central part Cw1 of the substrate W1 can be suppressed or prevented. When grooves 10 are processed in the edge part Ew1 of the substrate W1 with a water laser device, debris generated by laser processing on the surface of the groove 10 may cause a protrusion 10A (Figure 14(a)) to form a raised area around the opening of the groove 10 on the substrate surface near the opening of the groove 10. In this case, the protrusion 10A may be removed by polishing with a grinding wheel 30 (Figure 14(b)) before the CMP treatment is performed on the front surface of the substrate W1. In this way, it is possible to suppress or prevent deterioration of the planarization profile of the substrate W1 near the protrusion 10A during CMP processing due to the protrusion 10A. In addition, it is possible to suppress or prevent scratches on the substrate W1 caused by polishing debris peeling off from the protrusion.

[0025] In step (d) of Figure 2A, substrate W1 is bonded to substrate W2 in the same manner as in step (b) of Figure 1A (wafer bonding). This bonds the front surface of substrate W1 to the front surface of substrate W2, and the device region Dw1 of substrate W1 to the device region Dw2 of substrate W2. Subsequently, step (e) of Figure 2B is performed.

[0026] In step (e) of Figure 2B, the back surface of the substrate W1 of the laminated substrate after wafer bonding is ground with the grinding device 20 in the same manner as in step (c) of Figure 1A, thereby thinning the substrate W1. In this step, by thinning the back surface of the substrate W1 of the laminated substrate after wafer bonding, the central portion Cw1 and the edge portion Ew1 of the substrate W1 are separated by the groove 10 while both the central portion Cw1 and the edge portion Ew1 of the substrate W1 are bonded to the substrate W2.

[0027] When thinning the substrate W1, both the central portion Cw1 and the edge portion Ew1 are bonded to the substrate W2, which suppresses or prevents chipping of the edge portion Ew1 and the resulting cracks in the central portion Cw1. Compared to conventional methods that require forming a deeper trim to remove the substrate layer affected by chipping, the depth of the groove 10 formed in the substrate W1 can be reduced. This reduces the processing time for the groove.

[0028] In step (f) of Figure 2B, the back surface of the ground substrate W1 is etched to smooth or flatten the surface of the substrate W1. For example, wet etching using chemical solution 45 can be used for the etching process. This etching process is intended to smooth the back surface of the substrate W1 after grinding to some extent before the polishing process (step (g)), and can be omitted.

[0029] In step (g) of Figure 2B, the back surface of substrate W1 of the laminated substrate (W1, W2) is polished and flattened using a polishing device (e.g., a CMP device). The purpose of this polishing (CMP) process is to flatten the back surface of substrate W1 after the grinding process. In this polishing process, since the central part Cw1 and the edge part Ew1 of substrate W1 have the same thickness, deterioration of the edge profile at the edge of the central part Cw1 of substrate W1 can be suppressed or prevented.

[0030] In step (h) of Figure 2B, similar to step (d) of Figure 1A, the edge portion Ew1 of substrate W1 is removed from the laminated substrate (W1, W2) using a grinding wheel 30 or the like. After that, the semiconductor process is continued on the laminated substrate.

[0031] (Principle of suppressing chipping) Figures 3A and 3B are explanatory diagrams illustrating the principle of suppressing chipping of the substrate in a laminated substrate. Figure 3A shows the case where the substrate W1 after thinning (see step (c)) is thick and deep grooves 10 (see step (a)) are formed, while Figure 3B shows the case where the substrate W1 after thinning (see step (c)) is thin and shallow grooves 10 (see step (c)) are formed.

[0032] Before the thinning process of the substrate W1 of the laminated substrate (step (c) in Figures 1A and 1B, and step (e) in Figure 2B) begins (step (a) in Figures 3A and 3B), both the central portion Cw1 and the edge portion Ew1 of the substrate W1 are joined to the substrate W2 by the bonding portion 11 and supported by the substrate W2. Subsequently, even as the back surface of the substrate W1 is ground down and the substrate W1 becomes thinner from the back surface (step (b) in Figures 3A and 3B), both the central portion Cw1 and the edge portion Ew1 of the substrate W1 remain joined to and supported by the substrate W2 by the bonding portion 11. Furthermore, even when the bottom surface of the groove 10 is removed (exposing the opening of the groove 10 on the back surface of the substrate W1), and the central portion Cw1 and edge portion Ew1 of the substrate W1 are separated by the groove 10 (step (c) in Figures 3A and 3B), both the central portion Cw1 and edge portion Ew1 of the substrate W1 are joined and supported to the substrate W2 at the joint portion 11 on the front side. Therefore, chipping of the edge portion Ew1 of the substrate W1 and the occurrence of cracks at the edge of the central portion Cw1 of the substrate W1 due to chipping are suppressed. In other words, during the thinning process of the substrate W1 (steps (c) in Figures 1A and 1B, step (e) in Figure 2B, and steps (a) to (c) in Figures 3A and 3B), both the central portion Cw1 and the edge portion Ew1 of the substrate W1 are bonded to and supported by the substrate W2. This suppresses chipping of the edge portion Ew1 of the substrate W1 and prevents cracks from forming on the edges of the central portion Cw1 of the substrate W1 due to chipping.

[0033] In the thinning process of the substrate W1 of the laminated substrate, chipping and cracking can be suppressed, so the depth of the groove 10 can be several micrometers to several tens of micrometers greater than the thickness of the substrate W1 after thinning. For example, if the thickness of the substrate W1 after thinning is 10 μm, the depth of the groove 10 can be less than 100 μm. Therefore, the depth of the groove 10 can be less than 10 times the thickness of the substrate W1 after thinning.

[0034] In one example, the radial length of the edge portion Ew1 of the substrate W1 is approximately 3 mm, and the width of the groove 10 is approximately 20 μm. Approximately 2 mm of the flat portion (excluding the curved bevel portion) of the edge portion Ew1 of the substrate W1 is bonded to and supported by the substrate W2 (support substrate S in the embodiment described later). Although the curved bevel portion of the edge portion Ew1 is emphasized in Figure 3A and other figures, in reality, the flat portion of the edge portion Ew1 accounts for a larger proportion than is shown in the drawings.

[0035] In the method of forming a trim on the edge portion Ew of the substrate as shown in Figure 13 (pre-trim method), chipping occurs when the substrate W in the laminated substrate is thinned (step (b)), and the edge of the central portion Cw of the substrate becomes rough (the cross-section of the chipped area becomes an irregular uneven shape). For this reason, in order to remove the roughened portion, it was necessary to make the trim depth d1 (step (a)) about 10 times the thickness d0 of the substrate after thinning (see step (d)). On the other hand, in this embodiment, since chipping of the substrate edge portion during thinning can be suppressed, the depth of the groove 10 can be made significantly shallower.

[0036] (Method for removing the edge portion) Figures 4A to 4D are explanatory diagrams illustrating the method for removing the edge portion of the substrate W1.

[0037] In the example shown in Figure 4A, the laminated substrates (W1, W2) are rotated while the grinding wheel 30 is brought into contact with the edge portion Ew1 of substrate W1 from a vertical direction (a direction perpendicular to the surface of substrate W1) to remove the edge portion Ew1 of substrate W1.

[0038] In the example shown in Figure 4B, while rotating the laminated substrates (W1, W2), the lower surface of the grinding wheel 30 is made flush with the upper surface of substrate W2 (within the same plane), and the grinding wheel 30 is brought into contact with the edge portion Ew1 of substrate W1 in a horizontal direction, from the radially outer side of substrate W1 towards the radially inner side, thereby removing the edge portion Ew1 of substrate W1.

[0039] In the example of FIG. 4C, a grinding wheel 31 having an acute-angled key-shaped portion that enters between the edge portion Ew1 of the substrate W1 and the edge portion Ew2 of the substrate W2 is used. In this example, while rotating the laminated substrate (W1, W2), the lower surface of the grinding wheel 30 is made flush with the upper surface of the substrate W2 (within the same plane), and the grinding wheel 31 is brought close to and contacted with the edge portion Ew1 of the substrate W1 in the horizontal direction from the lateral side outside the radial direction of the substrate W1 toward the radial inside, to remove the edge portion Ew1 of the substrate W1.

[0040] In the example of FIG. 4D, while rotating the laminated substrate (W1, W2), an infrared irradiation device 41 irradiates infrared rays 42 onto the edge portion Ew1 of the substrate W1 to heat the edge portion Ew1, weakening the bonding force of the bonding portion 11 (for example, bonding agent / adhesive) between the edge portion Ew1 and the substrate W2, and removing the edge portion Ew1.

[0041] (Flowchart Example 1) FIG. 5A is an example of a flowchart of a method for manufacturing a laminated substrate according to the first embodiment.

[0042] In step S11, a groove 10 is formed in the edge portion Ew1 of the substrate W1 (steps (a) in FIGS. 1A and 1B, step (b) in FIG. 2A).

[0043] In step S12, a CMP process is performed on the front surface of the substrate W1 (step (c) in FIG. 2A).

[0044] In step S13, the substrate W1 and the substrate W2 are wafer-bonded (steps (b) in FIGS. 1A and 1B, step (d) in FIG. 2A).

[0045] In step S14, the back surface of the substrate W1 of the laminated substrate (W1, W2) is ground (thinned), and the central portion Cw1 and the edge portion Ew1 of the substrate W1 are separated in a state where both the central portion Cw1 and the edge portion Ew1 of the substrate W1 are bonded to the substrate W2 (steps (c) in FIGS. 1A and 1B, step (e) in FIG. 2B).

[0046] In step S15, a polishing process (CMP process) is performed on the back surface of the substrate W1 of the laminated substrate (step (g) in FIG. 2B). Note that an etching process (in FIG. 2B (f)) on the back surface of the substrate W1 of the laminated substrate may be included between step S14 and step S15.

[0047] In step S16, the edge portion Ew1 is removed from the substrate W1 of the laminated substrate (steps (d) in FIGS. 1A and 1B, step (h) in FIG. 2B). Thereafter, the wafer process for the laminated substrate is continued.

[0048] In step S11, when the groove 10 is processed in the edge portion Ew1 of the substrate W1 with a water laser device, convex portions 10A (FIG. 14(a)) may be generated in the form of raised portions around the opening on the substrate surface near the opening of the groove 10 due to debris generated by laser processing on the surface portion of the groove 10. In this case, after removing the convex portions 10A by polishing with a grindstone 30 or the like (step S12A in FIGS. 14(b) and 15)), in step S12, CMP processing may be performed on the front surface of the substrate W1. By doing so, it is possible to suppress or prevent the deterioration of the flattening profile of the substrate W1 in the vicinity of the convex portions 10A due to the convex portions 10A during the CMP processing. Further, it is possible to suppress or prevent the abrasive debris peeled off from the convex portions 10A from generating scratches on the substrate W1.

[0049] (Flowchart Example 2): FIG. 5B is another example of a flowchart of the method for manufacturing a laminated substrate according to the first embodiment.

[0050] In this example, as shown in steps S21 and S22 in FIG. 5B, before processing the groove 10 in the edge portion of the substrate W1 (step (b) in FIG. 2A), CMP processing is performed on the front surface of the substrate W1 (step (c) in FIG. 2A). In this case, in order to protect the front surface of the substrate W1 flattened by the CMP processing from the groove processing, a protective film is formed over the entire front surface of the substrate W1 (step S21A) between the CMP processing (step S21) and the groove processing (step S22). Then, after the groove processing (step S22), the protective film is removed (step S22A).

[0051] In step S21, CMP processing is performed on the front surface of the substrate W1 (step (c) in FIG. 2A).

[0052] In step S21A, a protective film is formed over the entire front surface of the substrate W1. The protective film is preferably a water-soluble resin such as PVA, because water-soluble resins can be easily removed with water. However, the protective film is not limited to water-soluble resins such as PVA; it may also be a resin such as polyimide or any other protective film material.

[0053] In step S22, a groove 10 is machined into the edge portion Ew1 of the substrate W1 (step (b) in Figure 2A).

[0054] In step S22A, the protective film is removed from the front surface of the substrate W1.

[0055] In step S23, substrates W1 and W2 are bonded together (step (d) in Figure 2A).

[0056] In step S24, the back surface of substrate W1 of the laminated substrate is ground (thinned), and while both the central portion Cw1 and the edge portion Ew1 of substrate W1 are bonded to substrate W2, the central portion Cw1 and the edge portion Ew1 of substrate W1 are separated (step (e) in Figure 2B).

[0057] In step S25, the back surface of the substrate W1 of the laminated substrate is polished (CMP treatment) (step (g) in Figure 2B). Note that an etching treatment on the back surface of the substrate W1 of the laminated substrate (f) in Figure 2B may be included between steps S14 and S15.

[0058] In step S26, the edge portion Ew1 is removed from the substrate W1 of the laminated substrate (step (h) in Figure 2B). After that, the wafer process on the laminated substrate is continued.

[0059] Furthermore, in order to improve the edge profile of the central part Cw1 of the substrate W1 during the polishing process (CMP process), it is preferable to perform edge removal (step S16 / step S26) after the polishing process (CMP process) (step S15 / step S25) following backside grinding, as shown in Figures 5A and 5B. However, depending on the required edge profile quality, the polishing process (CMP process) (step S15 / step S25) and edge removal (step S16 / step S26) in Figures 5A and 5B may be swapped.

[0060] (Modification) In the above, the substrate W2 is a wafer with a device area, but the substrate W2 may be replaced with a support wafer (support substrate) made of glass or the like that does not have a device area, or with adhesive tape. That is, the substrate W1 after groove processing may be bonded to a support wafer (support substrate) made of glass or the like, or with adhesive tape. When the substrate W1 is bonded to adhesive tape, it can be used as support for back grinding (backside grinding) of the substrate W1.

[0061] <Second Embodiment> (Manufacturing Method Example 1) Figure 6 shows an example of a manufacturing method for a laminated substrate according to the second embodiment.

[0062] In step (a) of Figure 6, the substrate W1 is bonded to the support substrate S (wafer bonding). At this time, the front surface of the substrate W1, including the device region Dw1, is brought into contact with the support substrate S for bonding. The substrate W1 is the same as described above. The support substrate S is a glass support wafer having the same shape as the substrate W1. The support substrate S is a substrate that does not include the device region, has high transmittance to the laser light used for groove processing, and is made of a material that is not processed by the laser light. In this embodiment, a glass substrate with transmittance that is not processed by the laser light used for groove processing is used as the support substrate S. This wafer bonding can be performed using adhesive bonding, anodic bonding, or any other bonding method.

[0063] In step (b) of Figure 6, a groove 10 is formed on the back surface of the substrate W1, along the boundary between the edge portion Ew1 and the central portion Cw1, extending around the entire circumference of the substrate and penetrating the entire thickness of the substrate W1. That is, by forming a groove 10 that penetrates from the back surface to the front surface of the substrate W1, the substrate W1 is cut so that the edge portion Ew1 and the central portion Cw1 are separated by the groove 10 while both the edge portion Ew1 and the central portion Cw1 of the substrate W1 are bonded to the support substrate S. The groove 10 can be formed, for example, by rotating the laminated substrate (substrate W1, support substrate S) and irradiating the back surface of the substrate W1 with laser light using a water laser device (described later). At this time, since the support substrate S is a glass substrate with high transmittance to laser light, it is possible to prevent the laser light from passing through and the support substrate S from being processed.

[0064] In step (c) of Figure 6, the back surface of substrate W1 of the laminated substrate (W1, S) after wafer bonding is ground by the grinding device 20 to thin the substrate W1 to a desired thickness. At this time, since both the central portion Cw1 and the edge portion Ew1 of substrate W1 are bonded and supported by the support substrate S, chipping of the edge portion Ew1 of substrate W1 and the occurrence of cracks at the edge of the central portion Cw1 of substrate W1 due to chipping are suppressed.

[0065] In step (d) of Figure 6, the edge portion Ew1 of substrate W1 is removed from the laminated substrate using a grinding wheel 30 or the like. After that, the semiconductor process is continued on the laminated substrate.

[0066] In the example shown in Figure 6, the grooves 10 are formed vertically, perpendicular to the surfaces (front and back) of the substrate W. However, as shown in Figure 1B, the grooves 10 may be formed at an angle to the surface of the substrate W. Similarly, in the manufacturing method examples described below, the grooves 10 may be formed perpendicular to the surface of the substrate W, or at an angle to the surface of the substrate W.

[0067] (Manufacturing Method Example 2) Figures 7A to 7C are schematic diagrams illustrating another example of the manufacturing method for a laminated substrate according to the second embodiment.

[0068] In step (a) of Figure 7A, the wafer-processed substrate W1 and the support substrate S are prepared. For the sake of explanation, we will assume that the substrate W1 and the support substrate S are prepared in step (a), but the support substrate S only needs to be prepared by the time of the bonding step with the substrate W1.

[0069] In step (b) of Figure 7A, the front surface of the substrate W1 is polished (CMP treatment) to flatten it. At this time, since the central part Cw1 and the edge part Ew1 of the substrate W1 have the same thickness, deterioration of the edge profile at the edge of the central part Cw1 of the substrate W1 can be suppressed or prevented.

[0070] In step (c) of Figure 7A, the substrate W1 is bonded to the support substrate S (wafer bonding), similar to step (a) of Figure 6A. At this time, the front surface of the substrate W1, including the device area Dw1, is brought into contact with the support substrate S for bonding. This wafer bonding can be performed using adhesive bonding, anodic bonding, or any other bonding method.

[0071] In step (d) of Figure 7A, similar to step (b) of Figure 6A, a groove 10 is formed from the back surface of the substrate W1 along the boundary between the edge portion Ew1 and the central portion Cw1, extending around the entire circumference of the substrate and penetrating the entire thickness of the substrate W1. That is, by forming a groove 10 that penetrates from the back surface to the front surface of the substrate W1, the substrate W1 is cut so that the edge portion Ew1 and the central portion Cw1 are separated by the groove 10 while both the edge portion Ew1 and the central portion Cw1 of the substrate W1 are bonded to the support substrate S. After that, step (e) of Figure 7B is performed.

[0072] In step (e) of Figure 7B, similar to step (c) of Figure 6A, the back surface of substrate W1 of the laminated substrate (W1, S) after wafer bonding is ground by the grinding device 20 to thin the substrate W1 to the desired thickness. At this time, since both the central portion Cw1 and the edge portion Ew1 of substrate W1 are bonded and supported by the support substrate S, chipping of the edge portion Ew1 of substrate W1 and the occurrence of cracks at the edge of the central portion Cw1 of substrate W1 due to chipping are suppressed. Prior to grinding the back surface of substrate W1, the protrusions 10A (Figure 14(a)) that occur on the substrate surface around the opening of the groove 10 may be removed by polishing with a grinding wheel 30 (Figure 14(b)) before the grinding process is performed on the back surface of substrate W1.

[0073] In step (f) of Figure 7B, the back surface of the ground substrate W1 is etched to smooth or flatten the surface of the substrate W1. For example, wet etching using chemical solution 45 can be used for the etching process. This etching process is intended to smooth the back surface of the substrate W1 after grinding to some extent before the polishing process (step (g)), and can be omitted.

[0074] In step (g) of Figure 7B, the back surface of the substrate W1 of the laminated substrate is polished and flattened using a polishing device (for example, a CMP device). The purpose of this polishing (CMP) process is to flatten the back surface of the substrate W1 after the grinding process. At this time, since the central part Cw1 and the edge part Ew1 of the substrate W1 have the same thickness, deterioration of the edge profile at the edge of the central part Cw1 of the substrate W1 can be suppressed or prevented.

[0075] In step (h) of Figure 7B, the edges of the substrate W1 are removed using a grinding wheel 30 or the like, similar to step (d) of Figure 6. Then, step (i) of Figure 7C is performed.

[0076] In step (i) of Figure 7C, a substrate W2 to be bonded to substrate W1 is prepared.

[0077] In step (j) of Figure 7C, the laminated substrate (W1, S) is bonded to substrate W2 (wafer bonding). At this time, the back surface of substrate W1 (the side opposite to the front surface where the device region Dw1 is formed) and the device region Dw2 of substrate W2 (not shown) are brought into contact with each other and bonded. This wafer bonding can be performed using adhesive bonding, anodic bonding, or any other bonding method.

[0078] In step (k) of Figure 7C, the support substrate S is removed from the substrate W1. For example, infrared light, ultraviolet light, etc., is used to weaken the bonding force between the substrate W1 and the support substrate S, thereby separating them. As a result, a laminated substrate (W1, W2) is obtained in which substrates W1 and W2 are bonded. Subsequently, the semiconductor process is continued on the laminated substrate (W1, W2). The subsequent semiconductor process includes, for example, forming through electrodes, etc., to electrically connect the device region Dw1 of substrate W1 and the device region Dw2 (not shown) of substrate W2.

[0079] (Principle of Chipping Suppression) Figure 8 is an explanatory diagram illustrating the principle of suppressing chipping of the substrate in a multilayer substrate.

[0080] Before the start of the thinning process of the substrate W1 described above (step (c) in Figure 6, step (e) in Figure 7B) (step (a) in Figure 8), both the central portion Cw1 and the edge portion Ew1 of the substrate W1 are joined to the support substrate S at the joint portion 11 and supported by the support substrate S. Subsequently, even as the back surface of the substrate W1 is ground down and the substrate W1 becomes thinner from the back surface (step (b) in Figure 8), both the central portion Cw1 and the edge portion Ew1 of the substrate W1 remain joined to and supported by the support substrate S. Furthermore, both the central portion Cw1 and the edge portion Ew1 of the substrate W1 remain joined to and supported by the support substrate S until the substrate W1 reaches the desired thickness (step (c) in Figure 8). In other words, during the thinning process of the substrate W1 (step (c) in Figure 6, step (e) in Figure 7B, and steps (a) to (c) in Figure 8), both the central portion Cw1 and the edge portion Ew1 of the substrate W1 are bonded to and supported by the support substrate S. Therefore, chipping of the edge portion Ew1 of the substrate W1 and the occurrence of cracks at the edges of the central portion Cw1 of the substrate W1 due to chipping are suppressed.

[0081] (Method for removing the edge portion) The edge portion of the substrate W1 (step (d) in Figure 6, step (h) in Figure 7B) can be removed in the same manner as in Figures 4A to 4D of the first embodiment. However, in Figures 4A to 4D, the substrate W2 is replaced with the support substrate S.

[0082] Furthermore, in this embodiment, in addition to the same method as in Figures 4A to 4D of the first embodiment, when a bonding agent / adhesive that peels off with UV light is used for wafer bonding, it is also possible to remove the edge portion Ew1 of the substrate W1 by irradiating only the edge portion Ew1 with UV light via the support substrate S. When this method is adopted, the support substrate S is selected to be a substrate made of a material (for example, glass) that has sufficiently high transmittance to the laser light for groove processing and the UV light for peeling off the bonding agent. Since the substrate W1 is bonded to a glass substrate (support substrate S) that transmits UV light, as shown in Figure 9, UV light 44 can be irradiated from the UV light irradiation device 43 to the bond portion 11 between the edge portion Ew1 of the substrate W1 and the support substrate S via the glass substrate (support substrate S). The UV light 44 weakens the bonding force of the bond portion 11 (bonding agent / adhesive) between the edge portion Ew1 of the substrate W1 and the support substrate S at the bond portion 11, and the edge portion Ew1 can be removed. At this time, the laminated substrate (W1, S) and / or the UV light irradiation device 43 are rotated to irradiate the joint 11 between the edge portion Ew1 and the support substrate S with UV light over the entire circumference of the substrate W1.

[0083] (Flowchart) Figure 10 is a flowchart of the manufacturing method of a laminated substrate according to the second embodiment.

[0084] In step S31, the front surface of the substrate W1 is subjected to CMP processing (step (b) in Figure 7A).

[0085] In step S32, the substrate W1 and the support substrate S are bonded together (step (a) in Figure 6, step (c) in Figure 7A).

[0086] In step S33, a groove 10 is machined into the edge portion of the substrate W1 to cut the substrate W1 so as to separate the central portion Cw1 from the edge portion Ew1 (step (b) in Figure 6, step (d) in Figure 7A).

[0087] In step S34, the back surface of the substrate W1 is ground (thinned) (step (c) in Figure 6, step (e) in Figure 7B).

[0088] In step S35, the back surface of the substrate W1 is polished (CMP treatment) (step (g) in Figure 7B). Note that an etching treatment on the back surface of the substrate W1 (step (f) in Figure 7B) may be included between steps S34 and S35.

[0089] In step S36, the edges of the substrate W1 are removed (step (d) in Figure 6, step (h) in Figure 7B). After that, the processes (i) to (k) in Figure 7C may be carried out.

[0090] Furthermore, in order to improve the edge profile of the central part Cw1 of the substrate W1 during the polishing process (CMP process), it is preferable to perform edge removal (step S36) after the polishing process (CMP process) (step S35) following backside grinding, as shown in Figure 10. However, depending on the required edge profile quality, the polishing process (CMP process) (step S35) and edge removal (step S36) in Figure 10 may be swapped.

[0091] (Configuration of the Water Laser Apparatus) Figures 11A and 11B are schematic diagrams showing the configuration of the water laser apparatus. Figure 11C is a cross-sectional view of the nozzle assembly of the water laser apparatus. Figure 11D is an enlarged view of the water jet flow and laser beam. Figure 11A shows the case where a groove is machined perpendicular to the surface of the substrate W1. Figure 11B shows the case where a groove is machined obliquely to the surface of the substrate W1. The only difference between the two is the inclination of the nozzle assembly 51; the other configurations are the same. Therefore, the configuration of Figure 11A will be described below with reference to Figures 11C and D.

[0092] The water laser apparatus (water jet laser apparatus) 500, given as an example of an apparatus used for groove processing in the above embodiment, includes, for example, a chuck table 55 for chucking and rotating the object to be processed (substrate W1), a nozzle assembly 51, a laser light source 52, and a high-pressure pump 53, as shown in Figure 11A. The high-pressure pump 53 receives liquid from a liquid supply source 54. The nozzle assembly 51, as shown in Figure 11C, includes a water chamber 511 for introducing liquid (pure water, etc.) supplied from the high-pressure pump 53, a nozzle 512 connected to the water chamber 511 for ejecting liquid (pure water, etc.), and an optical window 513 provided coaxially with the nozzle 512 and the laser light source 52 via the water chamber 511, for introducing laser light 62 from the laser light source 52 into the nozzle 512. The nozzle assembly 51 also includes optical components such as a focusing lens 514 for focusing the laser light from the laser light source 52. This water laser device (water jet laser device) 500 operates on a principle similar to that of optical fibers, irradiating a laser beam (for example, a 532 nm wavelength green laser beam) into a water jet stream of at least 30 μm in diameter, and guiding the beam to the target object after complete reflection. With this device, the water jet stream constantly cools the material (target object), and the rapid repetition of dissolution due to laser absorption suppresses the temperature rise in the processing area and efficiently removes the dissolved material.

[0093] As shown in Figure 11D, liquid (such as pure water) is ejected from the nozzle 512 of the nozzle assembly 51 toward the processing area of ​​the object to be processed (substrate W1), forming a water jet stream 61. At the same time, laser light 62 from the laser light source 52 travels through the nozzle assembly 51 into the water jet stream 61 and irradiates the processing area, thereby processing the area (forming the groove 10 described above). In this apparatus, liquid (such as pure water) is supplied to the nozzle assembly 51 by a high-pressure pump 53, and when the liquid (such as pure water) is ejected from the nozzle 512, laser light 62 is irradiated onto the substrate (wafer) through the liquid column (water jet stream 61) to perform processing. The substrate W1 is mounted on a chuck table 55, and the chuck table 55 rotates to perform groove processing around the entire circumference. The nozzle 512 (nozzle assembly 51) can be moved radially, or the chuck table 55 can be configured to be moved radially relative to the nozzle 512 (nozzle assembly 51). Furthermore, the object to be processed (substrate W1) and / or the components of the water laser device 500 (nozzle 512, etc.) may be rotated.

[0094] The water pressure of the water jet stream 61 can be, for example, up to 500 kbar. As shown in Figure 11D, the laser beam travels through the inside of the water jet stream 61, undergoing total internal reflection at the interface of the side surface of the water jet stream 61, and proceeds towards the tip of the water jet stream 61. As the laser beam, for example, a green laser with a wavelength of 532 nm can be used. The wavelength of the laser beam may be changed depending on the workpiece. The diameter (inner diameter) of the nozzle 512 is, for example, 30 μm to 120 μm. The maximum distance from the tip of the nozzle 512 to the deepest part of the workpiece (maximum length of the water jet stream 61: working range / working range) is, for example, about 1000 times the nozzle diameter. During groove machining, an air gap is formed between the side wall of the groove and the side surface of the water jet stream 61, and the diameter of the water jet stream 61 becomes 15% smaller than the nozzle diameter (about 85% of the nozzle diameter). In one example, when a laser rotates once on a substrate, a groove with a width of 50 μm and a depth of 30 μm is formed.

[0095] In a water laser system, because a liquid (such as pure water) is used, the thermal impact on the workpiece (e.g., substrate W1) can be reduced. Furthermore, misalignment between the laser beam's focal point and the workpiece surface is not a problem. Additionally, particles generated during processing can be flushed away with the liquid (such as pure water).

[0096] (Method for controlling groove depth and width) Figures 12A and 12B are explanatory diagrams illustrating the control principle of processing depth using a water laser device. In processing grooves 10 using a water laser device, the depth of the grooves 10 can be controlled by the rotation speed of the substrate during laser irradiation (rotations per unit time: rotational speed, e.g., rmp) and the number of rotations (cumulative number of rotations).

[0097] For example, if the groove 10 processed in one rotation of the substrate has a width of 50 μm and a depth of 30 μm, to process a groove with a width of 100 μm, the substrate and / or nozzle are moved horizontally, as shown in Figure 12B, so that they move relative to each other horizontally. Specifically, after rotating the substrate once, the substrate and / or nozzle are moved horizontally relative to each other, and then laser processing is performed while rotating the substrate once more. This processes a groove with a width of 100 μm, which is equivalent to two rotations of the substrate. Similarly, if the substrate is rotated N times, a groove with a width of 50 × N μm will be processed. Also, when processing a groove with a depth of 60 μm, as shown in Figure 12A, laser processing is performed while rotating the substrate twice at the same diameter position. Alternatively, the substrate and / or nozzle may be rotated to achieve relative rotation between the substrate and nozzle.

[0098] (Effects) (1) According to the above embodiment, when thinning the substrate, the edges of the substrate are joined and supported by the support (W2, S), so chipping of the edges can be suppressed. (2) According to the above embodiment, since the substrate is subjected to CMP treatment before the edges are removed from the substrate, deterioration of the edge profile of the central part of the substrate during the CMP process can be suppressed. (3) According to the above embodiment, chipping of the substrate edges can be suppressed and the processing depth of the grooves can be reduced, so the groove processing time can be shortened. (4) According to the above embodiment, compared to the method of applying a modified layer inside the edges of the substrate and cutting it (stealth laser method), the generation of cracks and particles due to cleavage of the central edge of the substrate during and after edge removal can be suppressed.

[0099] The present invention can also be described in the following embodiments. [1] According to one embodiment, a substrate processing method is provided, comprising the steps of: forming a groove along the circumferential direction at the boundary between the edge portion of the substrate and the central portion inside the edge portion on a first surface of the substrate; bonding the first surface of the substrate with the groove formed thereon to a support; and thinning the substrate by grinding a second surface opposite to the first surface of the substrate, and separating the central portion and the edge portion of the substrate by the groove while both the central portion and the edge portion of the substrate are bonded to the support. The depth of the groove shall be less than the thickness of the substrate. The support can be a substrate with a device area, a support substrate without a device area, an adhesive tape, or any other support that can be bonded to the substrate. The configuration in which the substrate and the support are bonded together is referred to as a laminate or laminated substrate.

[0100] In this configuration, while the substrate is being thinned, the central and edge portions of the substrate remain bonded to the support, and the central and edge portions are separated. This suppresses or prevents chipping of the edge portions during thinning. It also suppresses or prevents cracks from forming in the central portion of the substrate due to chipping.

[0101] Compared to conventional methods that require creating a deeper trim to remove the chipped layer of the substrate, this method allows for a smaller groove depth in the substrate. This reduces the processing time for the groove.

[0102] [2] According to one embodiment, after the step of separating the central portion and the edge portion, the further step of removing only the edge portion from the substrate is included.

[0103] In this configuration, the central and edge portions of the substrate are bonded to the support, and the edge portions, which are separated from the central portion, are removed. Therefore, when the edge portions are removed, cleavage or the like does not occur in the central portion of the substrate.

[0104] [3] In one embodiment, between the step of separating the central portion and the edge portion of the substrate and the step of removing only the edge portion from the substrate, the further step of applying CMP treatment to the second surface of the substrate while both the central portion and the edge portion of the substrate are bonded to the support is included.

[0105] In this configuration, since CMP processing is performed on the second surface of the substrate while both the central and edge portions of the substrate are bonded to the support, deterioration of the edge profile of the central portion of the substrate due to CMP processing can be suppressed. When CMP processing is performed on the substrate after the edge portions have been removed, there is a gap between the edge portions of the support and the polishing body (e.g., polishing pad), causing only the central portion of the substrate to sink into the polishing body, resulting in a problem where the polishing profile at the edge of the central portion of the substrate is not uniform with other parts (edge ​​profile issue). On the other hand, in this configuration, since CMP processing is performed on the substrate while both the central and edge portions of the substrate are supported by the support before the edge portions are removed from the substrate, deterioration of the edge profile of the central portion of the substrate can be suppressed or prevented.

[0106] [4] According to one embodiment, the process further includes a step of applying CMP treatment to the first surface of the substrate before or after the step of forming the groove on the first surface of the substrate, and before the step of joining the substrate to the support.

[0107] In this configuration, the substrate can be planarized by CMP before being bonded to the support, thus maintaining a good bond between the substrate and the support. Furthermore, since the CMP treatment is applied to the first surface of the substrate without removing the edges, deterioration of the edge profile in the center of the substrate due to the CMP treatment can be suppressed.

[0108] [5] In one embodiment, the step of applying CMP treatment to the first surface of the substrate before the step of forming the grooves on the first surface of the substrate is further included, and between the step of applying CMP treatment to the first surface of the substrate and the step of forming the grooves on the first surface of the substrate, the step of applying a protective film to the first surface of the substrate is further included.

[0109] According to this configuration, by applying a protective film to the first surface of the substrate after planarization by CMP processing, it is possible to prevent the first surface of the substrate after planarization by CMP processing from being scratched by grooving and / or from particles adhering to the first surface of the substrate after planarization by CMP processing.

[0110] [6] According to one embodiment, the process includes removing the protrusions formed at the opening of the groove before the step of applying CMP treatment to the first surface of the substrate. For example, the process further includes removing the protrusions around the opening of the groove (substrate surface) after the step of forming the groove on the first surface of the substrate and before the step of applying CMP treatment to the first surface of the substrate (prior to the step of joining the substrate to the support).

[0111] This configuration allows for the removal of protrusions (the shape of raised areas around the groove openings) that may occur during groove formation before CMP processing. This prevents or suppresses the deterioration of the substrate flattening profile near the protrusions during CMP processing. Furthermore, it prevents or suppresses the generation of scratches on the substrate by polishing debris that peels off from the protrusions.

[0112] [6A] In one embodiment, the groove may be formed such that its depth is less than 10 times the thickness of the substrate after thinning. In a method of thinning the substrate after trimming the edges, chipping occurs at the edges when the thinning process reaches the trim, and the edges of the central part of the substrate become rough due to the chipping, and / or cracks may occur toward the interior of the central part of the substrate. Therefore, the thickness of the trim (dimension in the substrate thickness direction) must be greater than the thickness of the substrate after thinning (about 10 times the thickness of the substrate after thinning) to remove the central part of the substrate where chipping occurs. On the other hand, in this embodiment, the occurrence of chipping can be suppressed or prevented when thinning the substrate, so the depth of the groove can be made shallower, less than 10 times the thickness of the substrate after thinning.

[0113] [7] According to one embodiment, a substrate processing method is provided, which includes the steps of: bonding a first surface of a substrate to a support; cutting the substrate by forming a groove along the circumferential direction at the boundary between the central portion and the edge portion of the substrate on a second surface of the substrate opposite to the first surface of the substrate; and thinning the substrate while both the central portion and the edge portion of the cut substrate are bonded to the support.

[0114] In this configuration, while the substrate is being thinned, the central and edge portions of the substrate remain bonded to the support, and the central and edge portions are separated. This suppresses or prevents chipping of the edge portions during thinning. It also suppresses or prevents cracks from forming in the central portion of the substrate due to chipping.

[0115] [8] According to one embodiment, the step of removing only the edge portion from the substrate is further included after the step of thinning the substrate.

[0116] In this configuration, the central and edge portions of the substrate are bonded to the support, and the edge portions, which are separated from the central portion, are removed. Therefore, when the edge portions are removed, cleavage or the like does not occur in the central portion of the substrate.

[0117] [9] In one embodiment, between the step of thinning the substrate and the step of removing only the edge portion from the substrate, the further step of applying CMP treatment to the second surface of the substrate while both the central portion and the edge portion of the substrate are bonded to the support is included.

[0118] In this configuration, since both the central and edge portions of the substrate are bonded to the support, CMP processing is applied to the second surface of the substrate, thus suppressing deterioration of the edge profile of the central portion of the substrate due to CMP processing.

[0119]

[10] In one embodiment, the first surface of the substrate is subjected to CMP treatment before the step of joining the first surface of the substrate to the support.

[0120] In this configuration, the substrate can be planarized by CMP before being bonded to the support, thus maintaining a good bond between the substrate and the support. Furthermore, since the CMP treatment is applied to the first surface of the substrate without removing the edges, deterioration of the edge profile in the center of the substrate due to the CMP treatment can be suppressed.

[0121]

[11] In one embodiment, the support is a glass substrate.

[0122] This configuration makes it possible to suppress or prevent the support from being processed when forming grooves in the substrate and cutting it. If the support is removed from the substrate in a later process, the support can be reused. Furthermore, if the bonding force at the joint between the substrate and the support is weakened by UV light, the edge portion of the joint can be removed by irradiating it with UV light through the glass substrate support.

[0123]

[12] According to one embodiment, in the step of forming the grooves in the substrate, a water laser is used to form the grooves.

[0124] In this configuration, a laser beam is passed through a laminar water jet directed onto the substrate to process grooves, thereby reducing the thermal impact on the substrate. Furthermore, grooves can be processed without problems even if the focal point of the laser beam is misaligned with the processing surface. Additionally, particles generated during processing can be washed away with water.

[0125]

[13] In one embodiment, the depth of the groove is controlled by the number of rotations per unit time and the cumulative number of rotations of the substrate relative to the water laser when the substrate is irradiated with the water laser. The rotation of the substrate is a relative rotation between the substrate and the water laser and can be carried out by rotating the substrate and / or the water laser.

[0126] This configuration allows for easy and precise control of the groove depth.

[0127]

[14] According to one embodiment, the width of the groove is controlled by rotating the substrate while moving the water laser and the substrate relative to each other in the radial direction of the substrate.

[0128] This configuration allows for easy and precise control of the groove width.

[0129]

[15] In one embodiment, the removal of the edge portion is carried out by grinding the edge portion with a grinding wheel while rotating the substrate, altering the bonding state between the edge portion and the support with UV light, or heating the edge portion with infrared light.

[0130] This configuration allows for the removal of edges using various methods.

[0131] While embodiments of the present invention have been described above, the embodiments of the invention described above are for the purpose of facilitating understanding of the present invention and do not limit it. The present invention can be modified and improved without departing from its spirit, and of course, the present invention includes equivalents thereof. Furthermore, any combination of embodiments and modifications is possible to the extent that at least some of the above-mentioned problems can be solved or at least some of the effects can be achieved, and any combination or omission of each component described in the claims and specification is possible.

[0132] All disclosures, including the specification, claims, drawings, and abstract, of Japanese Patent Publication No. 2003-143077 (Patent Document 1) are incorporated into this application by reference in their entirety. This application claims priority under Japanese Patent Application No. 2024-158010, filed on September 12, 2024. All disclosures, including the specification, claims, drawings, and abstract, of Japanese Patent Application No. 2024-158010, filed on September 12, 2024, are incorporated into this application by reference in their entirety.

[0133] 10 Groove 10A Protrusion 11 Joint 20 Grinding device 30 Grinding wheel 41 Infrared irradiation device 42 Infrared light 43 UV light irradiation device 44 UV light 45 Chemical solution 51 Nozzle assembly 52 Laser light source 53 High-pressure pump 54 Liquid supply source 55 Chuck table 61 Water jet flow 62 Laser light 511 Water chamber 512 Nozzle 513 Optical window 514 Focusing lens W1, W2 Substrate Ew1, Ew2 Edge part Cw1, Cw2 Center part Dw1, Dw2 Device area S Support substrate

Claims

1. A substrate processing method comprising: forming a groove on the first surface of the substrate along the boundary between the edge portion of the substrate and the central portion inside the edge portion; joining the first surface of the substrate on which the groove has been formed to a support; and thinning the substrate by grinding the second surface opposite to the first surface of the substrate, and separating the central portion and the edge portion of the substrate by the groove while both the central portion and the edge portion of the substrate are joined to the support.

2. A substrate processing method according to claim 1, further comprising the step of removing only the edge portion from the substrate after the step of separating the central portion and the edge portion.

3. A substrate processing method according to claim 2, further comprising the step of performing CMP processing on the second surface of the substrate while both the central portion and the edge portion of the substrate are bonded to the support, between the step of separating the central portion and the edge portion of the substrate and the step of removing only the edge portion from the substrate.

4. A substrate processing method according to claim 1, further comprising the step of applying CMP processing to the first surface of the substrate before or after the step of forming the groove on the first surface of the substrate, and before the step of joining the substrate to the support.

5. A substrate processing method according to claim 4, wherein the method further includes a step of applying CMP treatment to the first surface of the substrate before the step of forming the grooves on the first surface of the substrate, and further includes a step of applying a protective film to the first surface of the substrate between the step of applying CMP treatment to the first surface of the substrate and the step of forming the grooves on the first surface of the substrate.

6. A substrate processing method according to claim 4, comprising the step of removing a protrusion formed in the opening of the groove before the step of applying CMP processing to the first surface of the substrate.

7. A substrate processing method comprising: a step of joining a first surface of a substrate to a support; a step of forming a groove that penetrates the substrate in the edge portion along the boundary between the edge portion and the central portion inside the edge portion on the second surface of the substrate opposite to the first surface of the substrate, and cutting the substrate; and a step of thinning the substrate by grinding the second surface of the substrate while both the central portion and the edge portion of the cut substrate are joined to the support.

8. A substrate processing method according to claim 7, further comprising the step of removing only the edge portion from the substrate after the step of thinning the substrate.

9. A substrate processing method according to claim 8, further comprising the step of performing CMP processing on the second surface of the substrate while both the central portion and the edge portion of the substrate are bonded to the support, between the step of thinning the substrate and the step of removing only the edge portion from the substrate.

10. A substrate processing method according to claim 7, further comprising the step of applying CMP processing to the first surface of the substrate before the step of joining the first surface of the substrate to the support.

11. A substrate processing method according to claim 7, wherein the support is a glass substrate.

12. A substrate processing method according to any one of claims 1 to 11, wherein in the step of forming the grooves in the substrate, the grooves are formed using a water laser.

13. A substrate processing method according to claim 12, wherein the depth of the groove is controlled by the number of rotations per unit time and the cumulative number of rotations of the substrate relative to the water laser when the substrate is irradiated with the water laser.

14. A substrate processing method according to claim 12, wherein the width of the groove is controlled by rotating the substrate while moving the water laser and the substrate relative to each other in the radial direction of the substrate.

15. A substrate processing method according to any one of claims 1 to 11, wherein the removal of the edge portion is carried out by grinding the edge portion with a grinding wheel while rotating the substrate, altering the bonding state between the edge portion and the support with UV light, or heating the edge portion with infrared light.

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