Wafer cleavage separation device and cleavage separation method

Abstract

The present invention aims to provide a wafer cleavage separation device and a wafer cleavage separation method that can easily and reliably produce high-quality semiconductor crystal wafers. Provided in the present invention is a cleavage separation device for SiC wafers that are semiconductor crystal wafers. The device separates a wafer (W) into slices along a cutting guideline (G) formed on a planned cutting surface by scanning a focal point of a laser beam having a wavelength that allows transmission on a SiC ingot (Ig) which is a cylindrically shaped semiconductor crystal ingot. The device includes an ingot fixing unit

Description

Technical Field

[0001] This invention relates to a cleaving and separating apparatus and method for separating a wafer into slices along a cleaving guide line, wherein the cleaving guide line is formed by scanning a predetermined cleaving surface of a cylindrical semiconductor crystal ingot with a focal point formed by focusing laser light of a penetrating wavelength. Prior Technology

[0002] Conventional semiconductor wafer cleaving and separation apparatuses typically include: a separation layer formation step in which the semiconductor wafer is moved relative to the focal point of a laser beam having a wavelength that penetrates the semiconductor wafer ingot, thereby forming a separation layer on the semiconductor wafer ingot; and a separation step in which the wafer is separated from the semiconductor wafer ingot starting from the separation layer. In the separation step, the end face of the semiconductor wafer is held in place by the holding surface of the adsorption head, and wedges are driven into multiple locations along the circumferential direction of the semiconductor wafer ingot (not just one part of the side face) at the height of the separation layer. [Previous Technical Documents] [Patent Literature]

[0003] Patent Document 1: Japanese Patent Publication No. 2023-181727 Summary of the Invention

[0004] [The problem that the invention aims to solve] However, in the aforementioned conventional methods for splitting and separating semiconductor crystal wafers, as described in Patent Document 1, "the inventor confirmed through experiments that undesirable cracks would occur when an external force is applied to the whole wafer at once." Even with complex steps such as driving multiple wedges into the wafer along the circumferential direction of the semiconductor crystal wafer, undesirable cracks still occur. There is a strong desire to establish a simple and reliable method for splitting and separating the wafers.

[0005] In view of the above, the object of the present invention is to provide a wafer cleaving and separation apparatus and a cleaving and separation method that can simply and reliably manufacture high-quality semiconductor crystal wafers. [Methods used to solve problems]

[0006] The wafer slicing and separating device of the first invention separates a wafer into slices along a cutting guide line. The cutting guide line is formed by scanning a predetermined cutting surface of a cylindrical semiconductor crystal ingot with a focused point of laser light of a penetrating wavelength. The slicing and separating device comprises: The ingot fixing part is used to fix the aforementioned semiconductor crystal ingot; The mounting plate covers the entire end face of the aforementioned wafer side and is attached to that end face; and The tensile stress generating part is formed by applying a tensile load along the direction that separates the central part of the aforementioned attachment plate from the aforementioned semiconductor crystal ingot, thereby generating tensile stress in the attachment plate.

[0007] According to the wafer cleaving and separating apparatus of the first invention, when the wafer-side end face is completely covered by an attachment plate and the end face is attached to the attachment plate, a tensile load is applied along the direction that separates the central portion of the attachment plate from the semiconductor crystal ingot by a tensile stress generating part (at this stage, the attachment plate body does not deform), thereby generating tensile stress in the attachment plate. This tensile stress can act as tensile stress to separate the wafer from the central portion of the predetermined cutting surface through the wafer-side end face attached to the attachment plate.

[0008] Therefore, the undesirable cracks caused by promoting separation from the side of the semiconductor crystal ingot, as in conventional techniques, will not occur, and the splitting separation can be performed simply and reliably.

[0009] As described above, the wafer cleaving and separating device according to the first invention can easily and reliably manufacture high-quality semiconductor crystal wafers.

[0010] The wafer cleaving and separating device of the second invention is incorporated in the first invention. The aforementioned tensile stress generating part has: The base plate is a portion or all of the edge of the aforementioned attached plate, installed with a spacer in between; and The tension bolt is connected at one end to the center of the aforementioned attachment plate through a through hole formed in the center of the aforementioned base plate.

[0011] According to the wafer cleaving and separation device of the second invention, the tensile stress generating part is composed of a base plate and a tension bolt. The base plate is installed on the edge of the attachment plate through a spacer. One end of the tension bolt is connected to the center of the attachment plate through a through hole formed in the center of the base plate. Thus, a tensile load can be applied along the direction that stretches the center of the attachment plate from the semiconductor crystal ingot, thereby generating tensile stress in the attachment plate.

[0012] As described above, the wafer cleaving and separation method according to the second invention can easily and reliably manufacture high-quality semiconductor crystal wafers.

[0013] The wafer cleaving and separating device of the third invention is based on that of the second invention. The aforementioned spacer is installed facing the opposite edge, and the aforementioned through hole and the aforementioned tension bolt are arranged in the center of the aforementioned base plate in a manner parallel to the opposite edge.

[0014] According to the wafer cleaving and separating device of the third invention, tension bolts are arranged in the center of the base plate parallel to the spacer installed in a manner opposite to the edge of the opposite side, thereby enabling the tensile stress of the attachment plate and the tensile stress of the wafer side end face cut across the attachment plate to propagate from the arrangement direction.

[0015] By considering the propagation of tensile stress, the splitting process can be performed more simply and reliably. Leave.

[0016] As described above, the wafer cleaving and separation method according to the third invention can more easily and reliably manufacture high-quality semiconductor crystal wafers.

[0017] The wafer cleaving and separating device of the fourth invention is based on the third invention. The aforementioned mounting plate has continuous grooves formed on the side of the aforementioned wafer.

[0018] According to the wafer cleaving and separation device of the fourth invention, the attachment plate forms continuous grooves on the wafer-side surface (the surface on which the wafer-side end face of the semiconductor crystal ingot is attached), thereby making it easy to separate the separated wafer from the attachment plate.

[0019] As described above, the wafer cleaving and separation device according to the fourth invention can improve workability and easily and reliably manufacture high-quality semiconductor crystal wafers.

[0020] The wafer cleaving and separating device of the fifth invention is incorporated in the fourth invention. The aforementioned grooves are formed continuously along the orientation of the aforementioned spacers.

[0021] According to the wafer cleaving and separation device of the fifth invention, the grooves are continuously formed along the orientation of the aforementioned spacers, so that the attachment plate will not bend or deform under tensile load, and a predetermined tensile load can be applied along the direction that separates the central part of the attachment plate from the semiconductor crystal ingot, thereby generating tensile stress in the attachment plate.

[0022] The sixth invention discloses a wafer cleaving and separation method that separates a wafer into slices along a cleaving guide line. The cleaving guide line is formed by scanning a predetermined cleaving surface of a cylindrical semiconductor crystal ingot with a focused point of a laser beam of penetrating wavelength. The wafer cleaving and separation method comprises: The ingot fixing step involves fixing the aforementioned semiconductor crystal ingot having the aforementioned cutting guide lines formed thereon. The attachment step of attaching the entire end face of the aforementioned wafer to the attachment board; and A tensile stress generation step involves applying a tensile load along the direction that separates the central portion of the aforementioned attachment plate from the aforementioned semiconductor crystal ingot, thereby generating tensile stress in the attachment plate.

[0023] According to the wafer cleaving and separation method of the sixth invention, in a state where the wafer-side end face is entirely attached to the attachment plate by means of the attachment plate, a tensile load is applied along the direction that separates the central portion of the attachment plate from the semiconductor crystal ingot by means of a tensile stress generation step (at this stage, the attachment plate body does not deform), thereby generating tensile stress in the attachment plate. This tensile stress can act as a tensile stress that separates the wafer from the central portion of the predetermined cutting surface through the wafer-side end face attached to the attachment plate.

[0024] Therefore, the undesirable cracks caused by promoting separation from the side of the semiconductor crystal ingot, as in conventional techniques, will not occur, and the splitting separation can be performed simply and reliably.

[0025] As described above, the wafer cleaving and separation method according to the sixth invention can more easily and reliably manufacture high-quality semiconductor crystal wafers.

[0026] The wafer cleaving and separation method of the seventh invention is based on the sixth invention. The aforementioned tensile stress generation step involves applying a tensile load along the radial direction that separates the central portion of the aforementioned attached plate from the aforementioned semiconductor crystal ingot. According to the wafer cleaving and separation method of the seventh invention, a tensile load is applied as a whole along the radial direction including the central part of the attachment plate, thereby enabling the tensile stress of the attachment plate and the tensile stress of the wafer side end face cut across the attachment plate to be generated along the radial starting point.

[0027] By considering the propagation of tensile stress, the splitting process can be performed more simply and reliably. Leave.

[0028] As described above, the wafer cleaving and separation method according to the seventh invention can more easily and reliably manufacture high-quality semiconductor crystal wafers.

[0029] The wafer splitting and separation method of the eighth invention is based on the seventh invention, and includes the step of applying an external force to the end in the radial direction that causes the aforementioned tensile load to act.

[0030] According to the wafer cleaving and separation method of the eighth invention, an external force is applied to the end in the radial direction where the tensile load is applied, thereby forming a starting point as the trigger point for separation, so that separation can propagate from the aforementioned starting point along the radial direction of the tensile stress.

[0031] This allows for easier and more reliable splitting by utilizing the separation propagation generated by tensile stress.

[0032] As described above, the wafer cleaving and separation method according to the eighth invention can more easily and reliably manufacture high-quality semiconductor crystal wafers. Simple Explanation of the Diagram

[0033] Figure 1A is an explanatory diagram of the cleaving and separation device of the SiC wafer (semiconductor crystal wafer) of this embodiment, viewed from the side. Figure 1B is an explanatory diagram of the cleaving and separating device for SiC wafers (semiconductor crystal wafers) of this embodiment, viewed from above. Figure 2A is an explanatory diagram showing the cleaving and separation method of the SiC wafer (semiconductor crystal wafer) of this embodiment corresponding to Figure 1A. Figure 2B is an explanatory diagram showing the cleaving and separation method of the SiC wafer (semiconductor crystal wafer) of this embodiment, corresponding to Figure 1B. Figure 3A is an explanatory diagram showing the cleaving and separation method of the SiC wafer (semiconductor crystal wafer) of this embodiment corresponding to Figure 1A. Figure 3B is an explanatory diagram showing the cleaving and separation method of the SiC wafer (semiconductor crystal wafer) of this embodiment corresponding to Figure 1B. Figure 4A is an explanatory diagram showing the cleaving and separation method of the SiC wafer (semiconductor crystal wafer) of this embodiment corresponding to Figure 1A. Figure 4B is an explanatory diagram showing the cleaving and separation method of the SiC wafer (semiconductor crystal wafer) of this embodiment corresponding to Figure 1B. Implementation

[0034] As shown in Figures 1A and 1B, in this embodiment, the cleaving and separating device for the SiC semiconductor wafer is a scanning device that uses a laser beam of penetrating wavelength to focus the light at a focal point. A device for separating a SiC ingot Ig, which is a cylindrical semiconductor crystal ingot, into slices by forming a cutting guide line G on a predetermined cutting surface, and separating a wafer W into slices along the cutting guide line G from the above state, the device comprising: an ingot fixing part 1, an attachment plate 2, and a tensile stress generating part 3.

[0035] The ingot fixing part 1 is configured to fix the SiC ingot Ig. Specifically, the ingot fixing part 1 is composed of a metallic metal plate 11 and a base plate 12 integrally formed with the metal plate 11. The metallic metal plate 11 is attached to the end face of the SiC ingot Ig by bonding means such as adhesive or double-sided tape. Incidentally, as long as the ingot fixing part 1 is configured to fix the SiC ingot Ig, it can be any existing ingot fixing method, and is not limited to the metal plate 11 and the base plate 12.

[0036] The attachment plate 2 is an attachment plate that covers the entire end face of the wafer W side to be separated from the SiC ingot Ig, and is attached to the end face by bonding means such as adhesive or double-sided tape. In addition, the attachment plate 2 is basically the same as the metal plate 11.

[0037] Here, it is preferable to form at least a continuous groove 20 on the end face side of the wafer W on the attachment plate 2 (similarly, it is preferable to form a groove on the SiC ingot Ig of the metal plate 11).

[0038] The tensile stress generating part 3 is a means of generating tensile stress in the attachment plate 2 by applying a tensile load along the direction that separates the central part of the attachment plate from the SiC ingot Ig.

[0039] Specifically, the tensile stress generating part 3 has: a spacer 30, a base plate 31 and a tension bolt 32. The spacer 30 is located on part or all of the edge of the attachment plate 2. The base plate 31 is installed with respect to the spacer 30. One end of the tension bolt 32 is connected to the center of the attachment plate 2 through a through hole formed in the center of the base plate 31.

[0040] In this embodiment, although one end of the tension bolt 32 is screwed into the screw hole of the attachment plate 2 through the through hole, so that the tensile load is applied to the attachment plate 2 by rotating the tension bolt 32, it is also possible to provide a screw hole (instead of the through hole) in the center of the base plate 31, so that the tension bolt 32 is screwed into it and one end is fixed to the center of the attachment plate 2, so that the tensile load is applied to the attachment plate 2 by rotating the tension bolt 32.

[0041] The spacer 30 is preferably installed with its edges facing each other, while the tension bolts 32 are arranged in the center of the base plate 12, parallel to the opposite edge of the spacer 30. Incidentally, the spacer 30 can be, for example, double-sided tape of a predetermined thickness, or a thin film.

[0042] At this time, it is preferable that the groove 20 is formed continuously along the orientation of the opposing spacers 30 (e.g., in a back-and-forth manner between opposing spacers 30).

[0043] The SiC wafer cleaving and separation device constructed as described above is used as the SiC wafer cleaving and separation method described below.

[0044] First, a cutting guide line G is formed by scanning the predetermined cutting surface of the SiC ingot Ig with the focused point of a laser beam of penetrating wavelength (cutting guide line formation step). (Suddenly).

[0045] Next, the SiC ingot Ig with the cutting guide line G is attached to the metal plate 11 by a bonding means, with the end face opposite to the wafer W to be separated, thereby fixing the SiC ingot Ig (ingot fixing step).

[0046] Next, the wafer W-side end face of the SiC ingot Ig is attached to the attachment plate 2. At this time, adhesive is applied only to the protrusions of the grooves 20 formed on the attachment plate 2, and the end face of the SiC ingot Ig is attached to the surface formed by the coated grooves 20.

[0047] Subsequently, on the top surface of the attachment plate 2 (the surface opposite to the attachment surface of the SiC ingot Ig), spacers 30 are arranged in a relatively opposite manner at the edge of the side opposite to the arrangement direction of the screw holes of the tension bolt 32 (the same as the "radial direction" of the present invention).

[0048] Furthermore, on the upper surface of the attachment plate 2 on which the spacer 30 is provided, the base plate 31 is configured such that the arrangement direction of the through holes of the tension bolts 32 is parallel to the opposite spacer 30.

[0049] At this time, the positions of the through hole of the base plate 31 and the screw hole of the attachment plate 2 are aligned with each other in the vertical direction, and the plurality of bolts 32 are inserted into the through hole of the base plate 31 and screwed into the screw hole of the attachment plate 2, and a torque wrench or the like is used to rotate until the predetermined locking torque is reached.

[0050] As illustrated by the arrow in Figure 2A, a tensile load is applied along the direction that separates the central portion of the attachment plate 2 from the SiC ingot Ig (tensile load application step), thereby generating tensile stress in the attachment plate 2 (tensile stress generation step).

[0051] As shown schematically in Figure 2B, the tensile load will act on each part of the attachment plate 2 that is screwed into by the plurality of bolts 32 (in this state, the attachment plate 2 body will not deform), causing tensile stress around each bolt hole of the attachment plate 2.

[0052] Next, as shown in Figure 3A, when the plurality of tension bolts 32 are tightened to the predetermined locking torque, as shown in Figure 3B, the tensile stress generated in the attachment plate 2 (in this state, the attachment plate 2 body will not deform) will accumulate from each screw hole toward the spacer 30.

[0053] In this state, as shown in Figures 4A and 4B, an external force is applied to the end in the radial direction where the tensile load is applied (e.g., a hammer blow, or an impact generated by inserting an impact needle to cut the guide wire G). This causes the attachment plate 2 to displace from the tensile stress point of the tension bolt 32 on the side subjected to the external force. This displacement propagates sequentially to the tensile stress points of adjacent tension bolts 32. As a result, the attachment plate 2 also displaces from the point of application of the external force toward the arrangement direction of the tension bolts 32, thereby separating the wafer W (wafer separation step).

[0054] In this way, by applying external force to the end of the arrangement direction (radial direction) where the tensile load is applied, a starting point is formed as the trigger for separation, allowing separation to propagate along the radial direction of the tensile stress from the aforementioned starting point. Therefore, by utilizing the separation propagation generated by tensile stress, splitting separation can be performed more easily and reliably.

[0055] Furthermore, at this time, the deformation of the wafer W integrated with the attachment plate 2 is limited to the gap range between the attachment plate 2 and the substrate 31, which is determined by the thickness of the spacer 30. In other words, the deformation stops when the attachment plate 2 contacts the substrate 31, so the bending deformation of the wafer W integrated with the attachment plate 2 is limited to the gap width, which can prevent the wafer from breaking or cracking.

[0056] The above details the cleaving and separation method for SiC wafers according to this embodiment. As detailed above, SiC ingots can be precisely separated into sliced ​​SiC wafers, and high-quality SiC wafers can be manufactured simply and reliably.

[0057] Incidentally, the SiC wafer cleaving method of this embodiment, after the above series of processes, can also be subjected to a chemical mechanical polishing (CMP) step or a wafer cleaning step as needed.

[0058] Furthermore, although this embodiment describes the process of splitting and separating SiC wafers from SiC ingots using a semiconductor wafer splitting and separating apparatus and method, the semiconductor crystal is not limited to SiC, and can also be gallium phosphate, indium phosphide, silicon, or other compound semiconductors. body.

[0059] Furthermore, although this embodiment is described in the case where an external force is applied to the ends in the arrangement direction (radial direction), the separation propagation caused by tensile stress can also be initiated by other external or internal means without applying an external force. As for external means, sound waves (including ultrasound) or thermo-optical means can be used; as for internal means, further increases in tensile stress can be used.

[0060] Furthermore, in this embodiment, the tensile stress generating part 3 is constructed by the spacer 30, the base plate 31 and the tension bolt 32. However, it is not limited to this. Any means can be used as long as it can apply a predetermined tensile load to the central part of the attached plate.

[0061] 1: Ingot fixing part 2: Attaching the plate 3: Tensile stress generation part 11: Metal plate 12: Base Plate 20: Groove 30: Spacer 31: Base Plate 32: Tension bolt (bolt) G: Cut the guide wire Ig: SiC ingot (semiconductor crystal ingot) W: Wafer

Claims

1. A wafer slicing and separating device for separating a wafer into slices along a cutting guide line, the cutting guide line being formed by scanning a predetermined cutting surface of a cylindrical semiconductor crystal ingot with a focal point formed by focusing a laser beam of a penetrating wavelength. The slicing and separating device comprises: an ingot fixing part for fixing the semiconductor crystal ingot; an attachment plate for covering and attaching to the entire end face of the wafer; and a tensile stress generating part for applying a tensile load along the direction in which the central portion of the attachment plate is separated from the semiconductor crystal ingot, thereby generating tensile stress in the attachment plate.

2. The wafer cleaving and separating apparatus as described in claim 1, wherein, The aforementioned tensile stress generating part comprises: a base plate, which is installed on part or all of the edge of the aforementioned attachment plate through a spacer; and a tension bolt, one end of which is connected to the center of the aforementioned attachment plate through a through hole formed in the center of the aforementioned base plate.

3. The wafer cleaving and separating apparatus as described in claim 2, wherein, The aforementioned spacer is installed facing the opposite edge, and the aforementioned through hole and the aforementioned tension bolt are arranged in the center of the aforementioned base plate in a manner parallel to the opposite edge.

4. The wafer cleaving and separating apparatus as described in claim 3, wherein, The aforementioned mounting plate has continuous grooves formed on the side of the aforementioned wafer.

5. The wafer cleaving and separating apparatus as described in claim 4, wherein, The aforementioned grooves are formed continuously along the orientation of the aforementioned spacers.

6. A wafer slicing method, wherein the wafer is slicing into slices along a slicing guide line, the slicing guide line being formed by scanning a predetermined slicing surface of a cylindrical semiconductor crystal ingot with a focused point of a laser beam having a penetrating wavelength. The wafer slicing method comprises: an ingot fixing step, wherein the semiconductor crystal ingot having the aforementioned slicing guide line formed thereon is fixed; an attachment step, wherein the entire end face of the wafer is attached to an attachment plate; and a tensile stress generating step, wherein a tensile load is applied along the direction in which the center portion of the attachment plate is separated from the semiconductor crystal ingot, thereby generating tensile stress in the attachment plate.

7. The wafer cleaving and separation method as described in claim 6, wherein, The aforementioned tensile stress generation step involves applying a tensile load along the radial direction that separates the central portion of the aforementioned attached plate from the aforementioned semiconductor crystal ingot.

8. The wafer cleaving method as described in claim 7 includes an external force step, wherein the external force is applied to the end in the radial direction subjected to the aforementioned tensile load.

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