Method for manufacturing a substrate, and a substrate

Abstract

This design adheres to the chamfer shape specified in the standard while suppressing a decrease in polishing rate and variations. [Solution] The solution includes a chamfering step S40 which chamfers at least one of an inclined surface and a curved surface on the outer peripheral portion 2 of the boundary between the main surface 1a and the side surface 1b, and a polishing step S50 which polishes the main surface 1a, wherein the chamfering step S40 is an inclined surface that is in contact with the main surface 1a and the angle it makes with the main surface 1a is a first inclination angle θ1, or a curved surface that is in contact with the main surface 1a and the angle it makes with the main surface 1a is a first inclination angle θ1 The method includes a first chamfering step S41 for forming a first chamfered portion 3a, and a second chamfering step S42 for forming a second chamfered portion 3b of an inclined surface that is in contact with the first chamfered portion 3a and the side surface 1b, and the angle between it and the main surface 1a is a second inclination angle θ2 (>θ1), or a curved surface that is in contact with the first chamfered portion 3a and the side surface 1b, and the angle between the tangent line drawn from the point of contact with the first chamfered portion 3a and the main surface 1a is a second inclination angle θ2 (>θ1).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a substrate and a substrate.

Background Art

[0002] In the process of polishing a wafer when manufacturing a semiconductor wafer, so-called chemical mechanical polishing (CMP) is carried out by introducing slurry between the workpiece on the holding table and the polishing pad for polishing. In such polishing, since the amount of work applied to the outer peripheral portion of the polished wafer is larger than that of the central portion, so-called peripheral sag may occur, in which the thickness of the outer peripheral portion becomes thinner. Therefore, in the method for manufacturing a semiconductor wafer described in Patent Document 1, a chamfer portion is provided at the outer peripheral portion of the wafer in order to suppress peripheral sag and make the thickness of the polished wafer uniform.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the chemical mechanical polishing process described above, variations in the polishing rate, which indicates the amount of polishing per unit time, can occur depending on the hardness of the polishing pad and the size of the chamfered area. For example, if the hardness of the polishing pad is high and the inclination angle of the chamfered area is relatively large, polishing will be more dominant at the outer edge of the wafer than at the center, resulting in a decrease in the polishing rate at the center. Also, if the inclination angle of the chamfered area is reduced to match the hardness of the polishing pad, for example, it may no longer conform to the chamfer shape specified in the SEMI (Semiconductor Equipment and Materials International) standard.

[0005] The present invention provides a method for manufacturing a substrate that can suppress a decrease in polishing rate and variations while conforming to the chamfer shape defined in the standard, and also provides a substrate. [Means for solving the problem]

[0006] One aspect of the present invention is, A method for manufacturing a substrate having a main surface and side surfaces, A chamfering step of chamfering the outer periphery of the substrate, which is the boundary between the main surface and the side surface, so as to form at least one of an inclined surface and a curved surface, The polishing step includes polishing the main surface, The aforementioned chamfering step is, A first chamfering step is to form a first chamfered portion on the outer periphery of the substrate by forming an inclined surface that is in contact with the main surface and the angle it makes with the main surface is a first inclination angle, or by forming a curved surface that is in contact with the main surface and the angle it makes with the main surface that is a first inclination angle, The method includes a second chamfering step of forming an inclined surface that is in contact with the first chamfered portion and the side surface, and the angle formed with the main surface is a second inclination angle greater than the first inclination angle, or forming a curved surface that is in contact with the first chamfered portion and the side surface, and the angle formed between the tangent line drawn from the point of contact with the first chamfered portion and the main surface is a second inclination angle greater than the first inclination angle.

[0007] Furthermore, other embodiments of the present invention include: A substrate having a main surface and side surfaces, The outer periphery of the substrate, which is the boundary between the main surface and the side surface, is provided with a chamfered portion in which at least one of an inclined surface and a curved surface is formed. The chamfered portion is, A first chamfered portion is formed on the outer periphery of the substrate, wherein the inclined surface is in contact with the main surface and the angle it makes with the main surface is a first inclination angle, or the curved surface is in contact with the main surface and the angle it makes with the main surface is a first inclination angle, The present invention includes a second chamfered portion, which is in contact with the first chamfered portion and the side surface, and has an inclined surface formed thereon, where the angle between the first chamfered portion and the main surface is a second inclination angle greater than the first inclination angle, or a second chamfered portion, which is in contact with the first chamfered portion and the side surface, and has a curved surface formed thereon, where the angle between the tangent line drawn from the point of contact with the first chamfered portion and the main surface is a second inclination angle greater than the first inclination angle. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress a decrease in polishing rate and variations while adhering to the chamfer shape specified in the standard. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an enlarged view of the vicinity of the outer periphery 2 of the substrate 1, illustrating an example of a chamfered portion 3. [Figure 2] Figure 2 is a diagram illustrating another example of the chamfered portion 3. [Figure 3]FIG. 3 is a flowchart showing an example of the process of the method for manufacturing the substrate 1 in the embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of the manufacturing apparatus 10 for the substrate 1. [Figure 5] FIG. 5 is a diagram for explaining an example of the first laser processing apparatus 20a (second laser processing apparatus 20b). [Figure 6] FIG. 6 is a diagram showing an example of a state where a laser beam is irradiated from the surface 100a of the ingot 100. [Figure 7] FIG. 7 is a diagram for explaining an example of the peeling device 40. [Figure 8] FIG. 8 is a diagram for explaining a modified example of the peeling device 40. [Figure 9] FIG. 9 is a perspective view showing an example of the grinding device 60. [Figure 10] FIG. 10 is a diagram for explaining an example of the chamfering step S40. [Figure 11] FIG. 11 is a diagram for explaining the relationship between the inclination angle and the polishing rate. [Figure 12] FIG. 12 is an enlarged view of the vicinity of the chamfered portion 3. [Figure 13] FIG. 13 is a diagram for explaining the relationship between the compressive load and the amount of sinking of the polishing pad. [Figure 14] FIG. 14 is a diagram for explaining an example of the polishing device 80. [Figure 15] FIG. 15 is a diagram for comparing the polishing rates of the embodiment and the conventional example. [Figure 16] FIG. 16 is a diagram for explaining another example of the chamfering step S40.

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, a method for manufacturing a substrate according to an embodiment of the present invention and the substrate will be described with reference to the drawings. In the following description, the X-axis direction is one direction in the horizontal plane. The Y-axis direction is a direction orthogonal to the X-axis direction in the horizontal plane. The Z-axis direction is a direction orthogonal to the X-axis direction and the Y-axis direction.

[0011] [Substrate] First, the configuration of the substrate 1 will be described. The substrate 1 is, for example, a wafer such as a substantially disk-shaped semiconductor device wafer, an optical device wafer, etc. made of Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), etc.

[0012] FIG. 1 is an enlarged view near the outer peripheral portion 2 of the substrate 1. The substrate 1 includes a main surface 1a and a side surface 1b. The main surface 1a is a surface on which processes such as polishing and grinding are performed, and is, for example, the front or back surface of the substrate 1. In the example shown in FIG. 1, the front surface of the substrate 1 is shown on the upper side and the back surface of the substrate 1 is shown on the lower side. On the surface of the substrate 1, for example, a plurality of devices (not shown) such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in regions partitioned in a grid pattern. Note that the substrate 1 may be a so-called bare wafer on which no devices such as ICs and LSIs are formed on the surface. The side surface 1b is a surface in the thickness direction of the substrate 1 at the outer peripheral end of the substrate 1. Further, chamfering is performed on the outer peripheral portion 2 indicating the boundary between the main surface 1a and the side surface 1b, and the chamfered shape becomes a chamfered portion 3 having an inclined surface or a curved surface. In the example shown in FIG. 1, as an example, a chamfered portion 3 having an inclined surface is shown. Also, in the embodiment, as shown in FIG. 1, the chamfered portion 3 is chamfered in two steps between the main surface 1a and the side surface 1b.

[0013] Specifically, the chamfered portion 3 includes a first chamfered portion 3a and a second chamfered portion 3b. The first chamfered portion 3a has an inclined surface that contacts the main surface 1a on the outer peripheral portion 2 of the substrate 1, and the angle it makes with the main surface 1a is a first inclination angle θ1. Since the first chamfered portion 3a is in contact with the main surface 1a, it is polished together with the main surface 1a. The second chamfered portion 3b has an inclined surface that contacts the first chamfered portion 3a and the side surface 1b, and the angle it makes with the main surface 1a is a second inclination angle θ2 which is greater than the first inclination angle θ1. Here, the first inclination angle θ1 is an angle that can improve the polishing rate (hereinafter referred to as "polishing rate"), which is the amount of polishing per unit time when polishing the main surface 1a of the substrate 1, and may be determined, for example, based on experiments. Furthermore, the second inclination angle θ2 is set to an angle within a predetermined angular range based on SEMI standards, for example, and to an angle that can suppress outer edge rounding during polishing and edge chipping of the substrate 1. The specific process for forming the chamfered portion 3 will be explained later in the section on substrate manufacturing methods.

[0014] Thus, in this embodiment, a chamfered portion 3 is formed in two stages: a first chamfered portion 3a having a first inclination angle θ1, and a second chamfered portion 3b having a second inclination angle θ2 that is greater than the first inclination angle θ1. As a result, the chamfered portion as a whole can satisfy the inclination angle (i.e., chamfer angle) based on the SEMI standard, while the first inclination angle θ1 of the first chamfered portion 3a that is polished can be set to an inclination angle that improves the polishing rate. Furthermore, since the second inclination angle θ2 can be set to any angle within the predetermined angle range specified in the SEMI standard, it can be set to an angle that meets various requirements, such as an angle that can suppress the rounding of the outer circumference during polishing or an angle that can suppress edge chipping.

[0015] As mentioned above, the chamfered portion 3 may be formed by a curved surface in addition to an inclined surface, or by an inclined surface and a curved surface. Figures 2(a) to 2(c) show other examples of the chamfered portion 3. Figure 2(a) shows an example in which the first chamfered portion 3a is formed by an inclined surface and the second chamfered portion 3b is formed by a curved surface. In this case, the second inclination angle θ2 in the second chamfered portion 3b can be defined as "the angle between the tangent line drawn from the point of contact with the first chamfered portion 3a and the side surface 1b, and the main surface 1a."

[0016] Figure 2(b) shows an example in which the first chamfered portion 3a is formed as a curved surface and the second chamfered portion 3b is formed as an inclined surface. In this case, the first inclination angle θ1 in the first chamfered portion 3a can be defined as "the angle between the tangent line drawn from the point of contact with the main surface 1a and the main surface 1a, where the chamfered portion is tangent to the main surface 1a."

[0017] Figure 2(c) shows an example where both the first chamfered portion 3a and the second chamfered portion 3b are formed as curved surfaces. In this case, the first inclination angle θ1 in the first chamfered portion 3a and the second inclination angle θ2 in the second chamfered portion 3b may be defined in the same way as in Figure 2(a) and Figure 2(b). Note that in all examples in Figure 2, as in the example in Figure 1, the second inclination angle θ2 is greater than the first inclination angle θ1.

[0018] Furthermore, in the examples shown in Figures 1 and 2, the chamfered portion 3 is formed only on the front side of the substrate 1, but a similar chamfered portion 3 may also be formed on the back side of the substrate 1. In the following explanation, unless otherwise specified, the shape of the chamfered portion 3 will be assumed to be the shape shown in Figure 1.

[0019] [Manufacturing method for circuit boards] Next, a method for manufacturing a substrate will be described. Here, a series of processes will be described for manufacturing the beveled substrate 1 described above, including the beveling process, peeling the substrate 1 from the ingot 100, and polishing the peeled substrate 1. Figure 3 is a flowchart of an example of the method for manufacturing the substrate 1. The method for manufacturing the substrate 1 in this embodiment includes a peeling layer forming step S10, a peeling step S20, a grinding step S30, a beveling step S40, and a polishing step S50. The beveling step S40 includes a first beveling step S41 for forming the first beveled portion 3a described above, and a second beveling step S42 for forming the second beveled portion 3b.

[0020] Furthermore, in the manufacturing method of the substrate, each step is performed using a manufacturing apparatus 10 for the substrate 1 (hereinafter referred to as "manufacturing apparatus 10"). Figure 4 is a block diagram showing an example of the manufacturing apparatus 10. The manufacturing apparatus 10 includes a first laser processing apparatus 20a, a second laser processing apparatus 20b, a peeling apparatus 40, a grinding apparatus 60, and a polishing apparatus 80, and each step is performed using these apparatuses. Specifically, the peeling layer formation step S10 is performed by the first laser processing apparatus 20a, the peeling step S20 is performed by the peeling apparatus 40, the grinding step S30 is performed by the grinding apparatus 60, the chamfering step S40 is performed by the second laser processing apparatus 20b, and the polishing step S50 is performed by the polishing apparatus 80. Therefore, in the following, along with the explanation of each step, the first laser processing apparatus 20a, the second laser processing apparatus 20b, the peeling apparatus 40, the grinding apparatus 60, and the polishing apparatus 80 will be explained.

[0021] The manufacturing apparatus 10 may be configured as a single unit with, for example, the first laser processing apparatus 20a, the second laser processing apparatus 20b, the peeling apparatus 40, the grinding apparatus 60, and the polishing apparatus 80 mounted on a common base, or at least one apparatus may be configured as a separate unit mounted on a different base. Furthermore, the first laser processing apparatus 20a and the second laser processing apparatus 20b may have similar configurations, and therefore, the configuration of the first laser processing apparatus 20a will be described as representative here, while the description of the configuration of the second laser processing apparatus 20b will be omitted. In addition, the first laser processing apparatus 20a will be described using Figures 5 and 6, but each component shown in Figures 5 and 6 will be assumed to be common to both the first laser processing apparatus 20a and the second laser processing apparatus 20b.

[0022] Furthermore, the manufacturing apparatus 10 is provided with a control unit 200 that controls each of the devices. The control unit 200 may be a known computer that includes, for example, a control unit 210 that performs various calculations, a storage unit having a storage medium, and an input / output interface (none of which are shown) that controls the input and output of data to and from the inside and outside of the control unit. The control unit 210 executes various programs stored in the storage unit. For example, in the manufacturing process of the substrate 1 in the manufacturing apparatus 10, the control unit 210 executes each process in the flowchart shown in Figure 3 as an example of a program to improve the polishing rate when polishing the substrate 1.

[0023] (Exfoliation layer formation step) Step S10, the delamination layer formation step, is the step of forming a delamination layer S inside the ingot 100 using the first laser processing apparatus 20a. The first laser processing apparatus 20a will now be described.

[0024] Figure 5 is a schematic diagram of the first laser processing apparatus 20a. The first laser processing apparatus 20a includes a laser beam irradiation unit 21 that irradiates a laser beam and a first holding table 22 that holds the substrate 1 to be laser processed by suction.

[0025] The laser beam irradiation unit 21 includes, for example, a laser oscillator 21a that emits a YAG laser or a YVO4 laser, and an output adjustment unit 21b. Although not specifically shown, the laser oscillator 21a has a Brewster window, and the laser beam emitted from the laser oscillator 21a is a linearly polarized laser beam.

[0026] The laser beam, adjusted to a predetermined power by the output adjustment unit 21b of the laser beam irradiation unit 21, is reflected by the mirror 24 of the concentrator 23, and the focusing point is positioned inside the ingot 100, which is the workpiece held on the first holding table 22, by the focusing lens 25, and then irradiated. The concentrator 23 may also be provided with a vertical movement unit UD (not shown). The vertical movement unit UD is configured to move the position of the focusing lens 25 in the vertical direction. By controlling the vertical movement unit UD, the focusing point of the laser beam emitted from the laser oscillator 21a inside the ingot 100 can be moved.

[0027] Ingot 100 is, for example, a SiC single-crystal ingot or a GaN single-crystal ingot. Ingot 100 is not limited to a single-crystal ingot; it may also be a polycrystalline ingot.

[0028] Figure 6 shows the state in which a laser beam is irradiated from the surface 100a of the ingot 100 by the light concentrator 23. As shown in Figures 5 and 6, the first laser processing apparatus 20a forms a delamination layer S inside the ingot 100 by irradiating the surface 100a of the ingot 100 with a laser beam. Since the delamination layer S is formed inside the ingot 100, it is not normally visible on the surface 100a of the ingot 100. However, in the example in Figure 6, the delamination layer S is shown with a dashed line for the sake of explanation.

[0029] Using the first laser processing apparatus 20a configured in this way, in the delamination layer formation step S10, the control unit 210 irradiates the surface 100a of the ingot 100, which is held by the first holding table 22, with a laser beam having a wavelength that penetrates the ingot 100, and forms a delamination layer S by positioning the focal point of the laser beam at a position deeper than the surface 100a of the ingot 100. For example, the control unit 210 forms the delamination layer S by positioning the focal point of the laser beam at a depth corresponding to the thickness of the target substrate 1. Then, as shown in Figure 6, the control unit 210 processes and feeds the ingot 100 so that the focal point moves from one end to the other along the X-axis direction to form a delamination layer S along the X-axis direction, and then processes and feeds the ingot 100 by a predetermined amount in the Y-axis direction, and then processes and feeds the ingot 100 so that the focal point moves from the other end to the one end along the X-axis direction to form a delamination layer S along the X-axis direction, and repeats the process. As a result, a delamination layer S containing cracks is formed inside the ingot 100.

[0030] (Peeling step) Next, we will explain the peeling step S20. The peeling step S20 is the step of peeling the substrate 1 from the ingot 100 using the peeling device 40. Now, we will explain the peeling device 40.

[0031] Figure 7 is a schematic diagram illustrating the peeling apparatus 40. As shown in Figure 7, the peeling apparatus 40 includes an ultrasonic transducer 42 positioned opposite the surface 100a of the ingot 100 held on the second holding table 41 and applying ultrasonic waves to the ingot 100, a liquid supply nozzle 43 that supplies liquid (e.g., pure water) between the surface 100a of the ingot 100 and the ultrasonic transducer 42, and a transducer lifting mechanism 44 that adjusts the vertical position of the ultrasonic transducer 42.

[0032] The ultrasonic transducer 42 is positioned by the transducer lifting mechanism 44 so that a small gap is created between it and the surface 100a of the ingot 100. The liquid supply nozzle 43 continuously supplies liquid to the gap between the ultrasonic transducer 42 and the surface 100a of the ingot 100 while ultrasonic waves are applied to the ingot 100, forming a liquid layer WL. The ultrasonic waves irradiated from the ultrasonic transducer 42 are transmitted to the ingot 100 via the liquid layer WL, causing cracks in the delamination layer S formed on the ingot 100 to extend. This reduces the strength of the delamination layer S. After ultrasonic waves are applied to the surface 100a of the ingot 100, the surface 100a of the ingot 100 is attracted to a suction pad (not shown), and the suction pad is moved upward, allowing the thin plate including the surface 100a of the ingot 100 to be peeled off as the substrate 1, starting from the delamination layer S.

[0033] Note that the configuration of the peeling apparatus 40 is not limited to the configuration shown in Figure 7, but may also be the configuration shown in Figure 8, for example. Figure 8 is a diagram illustrating a modified peeling apparatus 40. The modified peeling apparatus 40 has a water tank WT in which liquid is stored, and an ultrasonic transducer 42 and an ingot 100 are placed in the liquid. That is, the ultrasonic waves irradiated from the ultrasonic transducer 42 are applied to the ingot 100 via the liquid stored in the water tank WT. Even with such a configuration, the substrate 1 can be peeled off from the ingot 100 starting from the peeling layer S.

[0034] Using the peeling apparatus 40 configured in this way, in the peeling step S20, the control unit 210 peels off a thin plate including the surface 100a of the ingot 100 as the substrate 1, starting from the peeling layer S. Specifically, the control unit 210 applies ultrasonic vibrations to the ingot 100 from the ultrasonic transducer 42. The ultrasonic waves irradiated from the ultrasonic transducer 42 are transmitted to the ingot 100 via the liquid layer WL, causing the cracks in the peeling layer S formed on the ingot 100 to extend. As a result, the strength of the peeling layer S decreases, the ingot 100 breaks starting from the peeling layer S, and the upper side of the ingot 100 is peeled off as the substrate 1.

[0035] (Grinding step) Next, the grinding step S30 will be explained. The grinding step S30 is a step in which the peeled surface of the substrate 1, which was peeled off in the peeling step S20, is flattened by the grinding device 60. The grinding device 60 will now be explained.

[0036] Figure 9 is a perspective view illustrating the grinding apparatus 60. The grinding apparatus 60 comprises a third holding table 61 that holds the substrate 1 to be ground by suction, and a grinding unit 70 that grinds the substrate 1 held by the third holding table 61. The third holding table 61 is connected to a rotational drive source (not shown), such as a motor, and can rotate around a rotation axis perpendicular to the holding surface by operating the rotational drive source.

[0037] The grinding unit 70, located above the third holding table 61, comprises a spindle 71 that is substantially perpendicular to the third holding table 61, and a rotational drive source (not shown), such as a motor, for rotating the spindle 71. A disc-shaped wheel mount 72 is fixed to the lower end of the spindle 71, and a grinding wheel 73 is fixed to the lower end of the wheel mount 72.

[0038] The grinding wheel 73 includes, for example, an annular base 74 made of a metal material such as stainless steel or aluminum, and a plurality of grinding wheels 75 arranged in an annular pattern on the lower surface of the base 74. The grinding wheels 75 include, for example, a binder made of ceramics, resin, metal material, etc., and countless abrasive grains such as diamond dispersed and fixed in the binder.

[0039] In the grinding apparatus 60 configured in this way, during the grinding step S30, the control unit 210 adjusts the positional relationship between the third holding table 61 and the grinding unit 70 so that the center of the substrate 1 held by the third holding table 61 coincides with the trajectory of the grinding wheel. Then, while rotating the third holding table 61 and the grinding wheel 73 respectively, the grinding wheel 73 is lowered along the processing feed direction (vertical direction) parallel to the rotation axis of the spindle 71, and grinding of the substrate 1 is started by bringing the lower surface of the grinding wheel 75 into contact with the substrate 1 held by the third holding table 61. As grinding of the substrate 1 progresses, the peeling layer S is removed and the substrate 1 is flattened.

[0040] (Chamfering step) Next, the chamfering step S40 will be described. The chamfering step S40 is a step in which a chamfered portion 3 is formed on the outer peripheral portion 2 of the substrate 1. The chamfering step S40 includes a first chamfering step S41 for forming a first chamfered portion 3a and a second chamfering step S42 for forming a second chamfered portion 3b, and this chamfering step S40 can be performed by the second laser processing apparatus 20b. As mentioned above, the configuration of the second laser processing apparatus 20b may be the same as that of the first laser processing apparatus 20a.

[0041] In the first chamfering step S41, the control unit 210 positions the focal point of the laser beam on the outer periphery 2 of the substrate 1 held by the first holding table 22 and irradiates it with the laser beam to form the first chamfered portion 3a. Figure 10(a) shows the state in which chamfering is being performed by irradiating with a laser beam by the light concentrator 23 in the second laser processing apparatus 20b, and Figure 10(b) shows the front view thereof. The laser beam may be irradiated from the vertical direction of the substrate 1, for example, as shown in Figure 10. The first holding table 22 is configured to be rotatable about the Z axis and to be movable in the X axis direction and the Y axis direction, respectively.

[0042] To describe the first chamfering step S41 in more detail, first, the substrate 1 is held by suction using the first holding table 22. Next, the substrate 1 is imaged by an imaging unit (not shown) provided in the second laser processing apparatus 20b, and the positional relationship between the substrate 1 and the light condenser 23 is adjusted based on the image captured. Then, the focusing point is positioned on the outer periphery 2 of the substrate 1.

[0043] Next, while rotating the first holding table 22 at a predetermined speed, a laser beam having a wavelength that absorbs the substrate 1 is irradiated along the outer edge indicated by the dashed line. Also, as described above, since the first holding table 22 is movable in the X-axis and Y-axis directions, the holding table is moved in an appropriate direction to move the focal point. In this way, the first chamfered portion 3a is formed by irradiating the entire circumference of the outer edge 2 of the substrate 1 with the laser beam.

[0044] Furthermore, the chamfering process performed by the second laser processing device 20b can accommodate various shapes by controlling the laser beam irradiation time, laser output, and processing feed rate. For example, as described above, the first inclination angle θ1 in the first chamfered section 3a is relatively smaller than the second inclination angle θ2 in the second chamfered section 3b. In this case, a relatively smaller inclination angle can be formed by shortening the irradiation time, reducing the laser output, or increasing the processing feed rate compared to when forming the second chamfered section 3b, as described later.

[0045] Furthermore, as described above, the first inclination angle θ1 of the first chamfered portion 3a is set to an angle that can improve the polishing rate. Generally, when the hardness of the polishing pad 95 in the polishing device 80 (see Figure 14) is high or low, the polishing rate is higher when the hardness of the polishing pad 95 is relatively high, and lower when the hardness of the polishing pad 95 is low. Therefore, in order to improve the polishing rate, it is preferable to use a polishing pad 95 with high hardness. On the other hand, if the hardness of the polishing pad 95 is high, the polishing pad 95 will not conform to the shape of the chamfered portion 3 of the outer peripheral portion 2 that is chamfered when polishing the substrate 1, so polishing on the outer peripheral portion 2 that is chamfered from the main surface 1a side of the substrate 1 will be more dominant, the polishing rate of the main surface 1a will be lower, and variations in the polishing rate may occur throughout the substrate. For this reason, it is preferable to set the first inclination angle θ1 of the first chamfered portion 3a that contacts the main surface 1a according to the hardness of the polishing pad 95. Furthermore, it is preferable to set the first inclination angle θ1 to an angle that increases the polishing rate.

[0046] Figure 11 shows the relationship between the inclination angle and the polishing rate. As can be seen from Figure 11, a relatively small inclination angle of the chamfered portion 3 results in an optimal inclination angle for the polishing pad 95 along the chamfered portion 3, leading to a higher polishing rate. In other words, to improve the polishing rate, when the hardness of the polishing pad 95 is high, it is preferable that the first inclination angle θ1 of the first chamfered portion 3a be small. In this embodiment, for example, the first inclination angle θ1 is set to about "10° to 20°" and chamfering is performed.

[0047] Furthermore, the distance D from the main surface 1a of the first chamfered portion 3a to the thickness direction of the substrate 1 (hereinafter also referred to as "distance D in the thickness direction of the substrate 1") may change depending on the first inclination angle θ1 of the first chamfered portion 3a. Here, the distance D in the thickness direction of the substrate 1 is the distance when a perpendicular line is drawn from the main surface 1a to the point of contact (or the height position corresponding to that point of contact) between the first chamfered portion 3a and the second chamfered portion 3b in the first chamfered portion 3a. Figure 12 shows an enlarged view of the vicinity of the chamfered portion 3 as a diagram to explain one example. The distance D in the thickness direction of the substrate 1 increases as the first inclination angle θ1 increases, and decreases as the first inclination angle θ1 decreases.

[0048] On the other hand, the polishing pad 95 used in the polishing step S50 described later sinks in the thickness direction of the substrate 1 as it polishes the substrate 1. Therefore, it is preferable that the distance D from the main surface 1a of the first chamfered portion 3a in the thickness direction of the substrate 1 be set according to the amount of sinking of the polishing pad 95. Specifically, it is preferable that the distance D in the thickness direction of the substrate 1 be greater than the amount of sinking of the polishing pad 95. In other words, it is preferable to set the first inclination angle θ1 such that the distance D in the thickness direction of the substrate 1 is greater than the amount of sinking of the polishing pad 95.

[0049] Furthermore, it is preferable that the distance D in the thickness direction of the substrate 1 is slightly larger than the amount the polishing pad 95 sinks in. This makes it possible to reduce the time required for processing the first chamfered portion 3a while making the distance D in the thickness direction of the substrate 1 larger than the amount the polishing pad 95 sinks in.

[0050] Here, we will explain how to determine the amount of sinking of the polishing pad 95. In this embodiment, the hardness (Asker-C) of the polishing pad 95 is, for example, 55 to 90 degrees, and the compression ratio of the polishing pad 95 is 2% to 15%. This range of compression ratio is due to the fact that if the compression ratio of the polishing pad 95 is 2% or less, the edges of the substrate 1 will chip, and if it is 15% or more, a high polishing rate cannot be obtained. Note that the hardness of the polishing pad 95 described above is the hardness of a typical polishing pad.

[0051] If the compression ratio of the polishing pad 95 is C, then the following equation holds true. Compression ratio C = (T1 - T2) / T1 ... Equation (1) Here, T1 and T2 are the thicknesses of the polishing pad 95 under a predetermined compressive load, for example, T1 being the compressive load W1 [g / cm 2 ] Pad thickness at time, T2 compressed load W2 [g / cm 2 Let the pad thickness at that time be [μm].

[0052] Furthermore, if we let d1 [μm] be the amount of sinking of the polishing pad 95 under the compressive load W1, and d2 [μm] be the amount of sinking of the polishing pad 95 under the compressive load W2, then the relationship shown in Figure 13 holds true.

[0053] In this case, for example, if we let d [μm] be the amount of sinking of the polishing pad 95 under an arbitrary compressive load W, then the amount of sinking d of the polishing pad 95 can be expressed by the following general formula, based on the relationship between the amount of sinking d1 of the polishing pad 95 under compressive load W1 and the amount of sinking d2 of the polishing pad 95 under compressive load W2. d=((d2-d1) / (W2-W1))×(W-W1)...Equation (2) Expanding equation (2) based on the relationship between T1, T2, and equation (1) described above, d=((T1-T2) / (W2-W1))×(W-W1)...Equation (3) =((C T1) / (W2-W1))×(W-W1)...Equation (4) This can be shown.

[0054] The control unit 200 pre-stores, for example, these relational expressions in its memory. The control unit 210 can refer to the memory and calculate the amount of sinking d of the polishing pad 95 according to various conditions such as the polishing pad 95. The control unit 210 then sets a first inclination angle θ1 such that the distance D in the thickness direction of the substrate 1 is slightly greater than the amount of sinking d of the polishing pad 95, and performs the first chamfering step S41 to achieve that first inclination angle θ1.

[0055] In the second chamfering step S42, the control unit 210 forms the second chamfered portion 3b using the second laser processing device 20b by the same means as in the first chamfering step S41. That is, the second chamfered portion 3b is formed by rotating the first holding table 22 at a predetermined speed and irradiating the outer edge of the substrate 1 with a laser beam having a wavelength that is absorbed by the substrate 1. In the second chamfering step S42, the control unit 210 positions the focal point of the laser beam on the outer edge 2 of the substrate 1 held by the first holding table 22 and irradiates the laser beam. At the same time, the first holding table 22 is moved as appropriate in the X-axis and Y-axis directions to move the focal point. In this way, the second chamfered portion 3b is formed by irradiating the entire circumference of the outer edge 2 of the substrate 1 with a laser beam.

[0056] As described above, the second inclination angle θ2 in the second chamfered portion 3b is greater than the first inclination angle θ1. This second inclination angle θ2 is set to an angle that can suppress outer edge rounding and edge chipping on the outer circumference 2 during polishing while satisfying SEMI standards, for example. This angle may be 45°, for example. Therefore, the control unit 210 forms the desired second chamfered portion 3b by controlling the laser beam irradiation time, laser output, processing feed rate, etc.

[0057] The order of the first chamfering step S41 and the second chamfering step S42 may be reversed; that is, the first chamfering step S41 may be performed after the second chamfering step S42. The control unit 210 may also perform the same chamfering step S40 on the back side of the substrate 1.

[0058] (Polishing step) Next, we will explain the polishing step S50. The polishing step S50 is a step in which the flattened substrate 1 is polished to a mirror finish using the polishing device 80. Now, let's explain the polishing device 80.

[0059] Figure 14 is a schematic diagram illustrating the polishing apparatus 80. The polishing apparatus 80 comprises a fourth holding table 81 for suction holding the substrate 1, and a polishing unit 90 for polishing the substrate 1 held on the fourth holding table 81.

[0060] The fourth holding table 81 is configured to rotate freely around the Z-axis as its center of rotation. The fourth holding table 81 has a disc-shaped frame 82 made of non-porous ceramics. A disc-shaped recess is formed in the radial center of the frame 82, and a porous plate 83 made of porous ceramics is fixed to this recess. The upper surface of the porous plate 83 constitutes a holding surface 84 that holds the substrate 1 by suction.

[0061] A polishing unit 90 is positioned above the fourth holding table 81. The polishing unit 90 has a cylindrical spindle housing (not shown) that is positioned substantially parallel to the Z-axis direction. A cylindrical spindle 91, positioned along the Z-axis direction, is rotatably housed in the spindle housing. A rotational drive source (not shown), such as a motor, for rotating the spindle 91 is provided near the upper end of the spindle 91.

[0062] The lower end of the spindle 91 is connected to a disc-shaped mount 92. The mount 92 has a diameter larger than the diameter of the holding surface 84. A disc-shaped polishing tool 93, which has approximately the same diameter as the mount 92, is attached to the lower surface of the mount 92 via a fixing member such as a bolt.

[0063] The polishing tool 93 has a disc-shaped platen 94 connected to the lower surface of the mount 92. The platen 94 is made of hard resin and has approximately the same diameter as the mount 92. A disc-shaped polishing pad 95 is fixed to the lower surface of the platen 94.

[0064] The polishing pad 95 is made of, for example, rigid polyurethane foam, but may also have a nonwoven fabric instead of rigid polyurethane foam. When polishing the substrate 1 with the polishing pad 95, the substrate 1 is polished using a slurry containing free abrasive particles.

[0065] The polishing tool 93 is positioned concentrically with the spindle 91 and the mount 92. A through-hole 96 is formed in the radial center of the polishing tool 93, passing through the polishing pad 95, the platen 94, the mount 92, and the spindle 91. A slurry supply source (not shown) is connected to the upper end of the through-hole 96. The through-hole 96 functions as a slurry supply passage 97 that supplies slurry to the substrate 1 and the polishing pad 95 when the substrate 1 is polished with the polishing pad 95.

[0066] In the polishing apparatus 80 configured as described above, during the polishing step S50, the control unit 210 holds the substrate 1 by suction on the holding surface 84 and positions the fourth holding table 81 below the polishing tool 93. The spindle 91 and the fourth holding table 81 are rotated at different rotational speeds, and the polishing pad 95 is lowered while supplying slurry from the slurry supply passage 97 to the surface of the substrate 1 and the lower surface of the polishing pad 95. The polishing pad 95 is then pressed against the substrate 1 with a predetermined pressure, pressing the lower surface of the polishing pad 95 against the surface of the substrate 1. In this way, the main surface 1a of the substrate 1 is polished. During the polishing process, the polishing pad 95 may also be slightly reciprocated in the X-axis direction along a line connecting the center of the polishing pad 95 and the center of the substrate 1. This allows for more uniform polishing of the entire substrate. In this way, the main surface 1a of the substrate 1 is polished to a mirror finish. The same polishing step S50 process may also be performed on the back surface of the substrate 1.

[0067] As described above, in this embodiment, a two-stage chamfered portion 3, including a first chamfered portion 3a and a second chamfered portion 3b, is formed on the outer peripheral portion 2 of the substrate 1, and the main surface 1a and a part of the outer peripheral portion 2 of the first chamfered portion 3a that is in contact with the main surface 1a are polished. At this time, the first inclination angle θ1 of the first chamfered portion 3a is smaller than the second inclination angle θ2 of the second chamfered portion 3b, as described above, and is a relatively small inclination angle that takes the polishing rate into consideration. Therefore, it is possible to suppress the polishing of the outer peripheral portion 2 from being more dominant than the main surface 1a of the substrate 1, and as a result, it is possible to suppress variations in the polishing rate between the main surface 1a and the outer peripheral portion 2, and to improve the polishing rate of the entire substrate.

[0068] For example, compared to a conventional shape that consists of a single chamfered section with a 45° inclination angle to suppress edge chipping, the polishing rate can be improved. Figure 15 is a diagram for comparing the polishing rates of the conventional shape and the embodiment, showing an example where the same substrate is used and measurements are taken under the same conditions, except for the chamfered shape. As can be seen from Figure 15, in the embodiment, it is possible to improve the polishing rate by about 1.5 times compared to the conventional shape.

[0069] Furthermore, in this embodiment, as described above, the first inclination angle θ1 in the first chamfered portion 3a is a relatively small angle, and the second inclination angle θ2 in the second chamfered portion 3b is an angle that can suppress outer edge rounding and edge chipping of the outer circumference 2 while satisfying SEMI standards. Therefore, it is possible to improve the polishing rate while fulfilling these conditions and requirements. Moreover, since the configuration is such that a first chamfered portion 3a with a relatively small first inclination angle θ1 is added to the conventional shape, the design changes are small, or in other words, these effects can be achieved without making significant changes to the shape from the conventional shape.

[0070] Although each embodiment has been described above with reference to the drawings, it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications and alterations can be conceived within the scope of the claims, and these are also understood to naturally fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined arbitrarily without departing from the spirit of the invention.

[0071] For example, in the embodiment described above, the chamfering step S40 is configured to be performed after the grinding step S30 and before the polishing step S50 described later, but the chamfering step S40 only needs to be performed at least before the polishing step S50.

[0072] Furthermore, in the chamfering step S40, in the example shown in Figure 10, the chamfered portion 3 was formed by irradiating the substrate 1 from the vertical direction. However, the laser beam may be irradiated not only from the vertical direction of the substrate 1, but also from a horizontal direction parallel to the substrate 1, for example, as shown in Figures 16(a) and (b). Alternatively, the laser beam may be irradiated from a predetermined angle, such as 45°, between the substrate 1 and the laser beam.

[0073] Furthermore, as described above, the shape of the chamfered portion 3 may be such that a curved surface is formed on at least one of the first chamfered portion 3a and the second chamfered portion 3b, as shown in Figure 2.

[0074] Furthermore, in the above-described embodiment, it was explained that the distance D in the thickness direction of the substrate 1 is preferably slightly larger than the amount of sinking of the polishing pad 95. However, the distance D in the thickness direction may be, for example, a value that takes into account a predetermined margin with respect to the amount of sinking of the polishing pad 95.

[0075] Furthermore, in the above-described embodiment, when manufacturing the substrate 1 from the ingot 100, a laser beam was used to form a release layer S inside the ingot 100, and the thin plate was peeled off from the ingot 100 as the substrate 1, starting from the release layer S. On the other hand, the means for cutting the substrate 1 from the ingot 100 is not limited to a laser beam, and it may also be manufactured by cutting it using a wire saw, as is conventionally known.

[0076] Furthermore, the method for manufacturing the substrate described in the above-described embodiment can be realized by executing a pre-prepared control program on a computer. This control program is recorded on a computer-readable storage medium and executed when read from the storage medium. This control program may also be provided in the form of a non-transient storage medium such as flash memory, or it may be provided via a network such as the Internet. The computer that executes this control program may be included in the device, or it may be included in an electronic device such as a smartphone, tablet terminal, or personal computer that can communicate with the device, or it may be included in a server device that can communicate with these devices and electronic devices.

[0077] This specification contains at least the following information. Note that the components etc. in parentheses indicate those corresponding to the embodiments described above, but are not limited thereto.

[0078] (1) A method for manufacturing a substrate (substrate 1) having a main surface (main surface 1a) and a side surface (side surface 1b), A chamfering step (chamfering step S40) is performed to chamfer the outer peripheral portion (outer peripheral portion 2) of the substrate, which is the boundary between the main surface and the side surface, so as to form at least one of an inclined surface and a curved surface. The system includes a polishing step (polishing step S50) for polishing the main surface, The aforementioned chamfering step is, A first chamfering step (first chamfering step S41) is performed in which, on the outer periphery of the substrate, an inclined surface is formed that is in contact with the main surface and the angle formed with the main surface is a first inclination angle (first inclination angle θ1), or a curved surface is formed that is in contact with the main surface and the angle formed between the tangent line drawn from the point of contact with the main surface and the main surface is a first inclination angle, thereby forming a first chamfered portion (first chamfered portion 3a), The method includes a second chamfering step (second chamfering step S42) which involves forming the inclined surface such that it is in contact with the first chamfered portion and the side surface, and the angle between it and the main surface is a second inclination angle (second inclination angle θ2) that is greater than the first inclination angle, or forming the curved surface such that it is in contact with the first chamfered portion and the side surface, and the angle between the tangent line drawn from the point of contact with the first chamfered portion and the main surface is a second inclination angle that is greater than the first inclination angle, thereby forming a second chamfered portion (second chamfered portion 3b), A method for manufacturing a circuit board.

[0079] According to (1), the inclination angle of the first chamfered portion in contact with the main surface can be set to a relatively small angle. Therefore, it is possible to suppress the dominance of polishing on the outer periphery of the substrate, and as a result, it is possible to suppress variations in the polishing rate between the main surface and the outer periphery, and to improve the overall polishing rate of the substrate. Furthermore, since the second chamfered portion does not contact the main surface, it is not affected by the polishing rate and can be set to any angle, so that a desired inclination angle can be set that suppresses edge chipping, etc., while complying with standards. In other words, it is possible to improve the polishing rate of the entire chamfered portion while achieving a desired chamfered shape.

[0080] (2) A method for manufacturing a substrate as described in (1), The aforementioned chamfering step is, The first inclination angle is set according to the hardness of the polishing pad (polishing pad 95) used in the polishing step. A method for manufacturing a circuit board.

[0081] According to (2), the polishing rate can be improved by setting the first inclination angle according to the hardness of the polishing pad.

[0082] (3) A method for manufacturing a substrate as described in (2), The first inclination angle is, The harder the polishing pad, the smaller the size. A method for manufacturing a circuit board.

[0083] According to (3), the higher the hardness of the polishing pad, the higher the polishing rate, or in other words, the easier it is to polish the chamfered area. Therefore, the higher the hardness of the polishing pad, the smaller the first inclination angle, which suppresses the relative progress of polishing of the outer periphery to the main surface. As a result, variations in the polishing rate between the main surface and the outer periphery can be suppressed, and the overall polishing rate of the substrate can be improved.

[0084] (4) A method for manufacturing a substrate as described in (1) or (2), The aforementioned chamfering step is, The distance from the main surface of the first chamfered portion in the thickness direction of the substrate (distance D in the thickness direction of the substrate) is set according to the amount of sinking of the polishing pad (polishing pad 95) into the main surface during polishing in the polishing step. A method for manufacturing a circuit board.

[0085] According to (4), the distance from the main surface of the first chamfered portion in the thickness direction of the substrate can be set to an appropriate distance corresponding to the amount of sinking of the polishing pad, and as a result, the polishing rate can be improved.

[0086] (5) A method for manufacturing a substrate as described in (4), The distance in the thickness direction is, This value is greater than the amount of sinking of the aforementioned polishing pad. A method for manufacturing a circuit board.

[0087] According to (5), since the distance in the thickness direction of the substrate is greater than the amount the polishing pad sinks in, the polishing pad can avoid contact with the inclined or curved surface of the first chamfered portion, and the main surface can be polished appropriately.

[0088] (6) A substrate (substrate 1) having a main surface (main surface 1a) and a side surface (side surface 1b), The outer periphery (outer periphery 2) of the substrate, which is the boundary between the main surface and the side surface, is provided with a chamfered portion (chamfered portion 3) having at least one of an inclined surface and a curved surface formed thereon. The chamfered portion is, On the outer periphery of the substrate, a first chamfered portion (first chamfered portion 3a) is formed, which is in contact with the main surface and has an inclined surface that forms a first inclination angle (first inclination angle θ1) with the main surface, or a curved surface is formed that is in contact with the main surface and has an angle between the tangent line drawn from the point of contact with the main surface and the main surface that forms a first inclination angle. The invention includes a second chamfered portion (second chamfered portion 3b) which is in contact with the first chamfered portion and the side surface, and has an inclined surface formed such that the angle between it and the main surface is a second inclination angle (second inclination angle θ2) that is greater than the first inclination angle, or a second chamfered portion (second chamfered portion 3b) which is in contact with the first chamfered portion and the side surface, and has a curved surface formed such that the angle between the tangent line drawn from the point of contact with the first chamfered portion and the main surface is a second inclination angle that is greater than the first inclination angle, substrate.

[0089] According to (6), the inclination angle of the first chamfered portion in contact with the main surface can be set to a relatively small angle. Therefore, it is possible to suppress the dominance of polishing on the outer periphery of the substrate, and as a result, it is possible to suppress variations in the polishing rate between the main surface and the outer periphery. In other words, the polishing rate of the entire substrate can be improved. Furthermore, since the second chamfered portion does not contact the main surface, it is not affected by the polishing rate and can be set to any angle, so that a desired inclination angle can be set that suppresses edge chipping, etc., while complying with standards. In short, the polishing rate of the entire chamfered portion can be improved while achieving the desired chamfered shape. [Explanation of Symbols]

[0090] 1 circuit board 1a Main surface 1b side 2. Outer periphery 3. Chamfered section 3a First chamfered section 3b Second chamfered section 95 Polishing Pads D Distance in the thickness direction of the substrate θ1 1st inclination angle θ2 2nd inclination angle S40 Chamfered Step S41 First chamfering step S42 Second chamfering step S50 Polishing Step

Claims

1. A method for manufacturing a substrate having a main surface and side surfaces, A chamfering step of chamfering the outer periphery of the substrate, which is the boundary between the main surface and the side surface, so as to form at least one of an inclined surface and a curved surface, The polishing step includes polishing the main surface, The aforementioned chamfering step is, A first chamfering step is to form a first chamfered portion on the outer periphery of the substrate by forming an inclined surface that is in contact with the main surface and the angle it makes with the main surface is a first inclination angle, or by forming a curved surface that is in contact with the main surface and the angle it makes with the main surface that is a first inclination angle, The method includes a second chamfering step of forming the inclined surface such that it is in contact with the first chamfered portion and the side surface, and the angle between it and the main surface is a second inclination angle greater than the first inclination angle, or forming the curved surface such that it is in contact with the first chamfered portion and the side surface, and the angle between the tangent line drawn from the point of contact with the first chamfered portion and the main surface is a second inclination angle greater than the first inclination angle, A method for manufacturing a circuit board.

2. A method for manufacturing a substrate according to claim 1, The aforementioned chamfering step is, The first inclination angle is set according to the hardness of the polishing pad used in the polishing step. A method for manufacturing a circuit board.

3. A method for manufacturing a substrate according to claim 2, The first inclination angle is, The harder the polishing pad, the smaller the size. A method for manufacturing a circuit board.

4. A method for manufacturing a substrate according to claim 1 or 2, The aforementioned chamfering step is, The distance from the main surface of the first chamfered portion to the thickness direction of the substrate is set according to the amount the polishing pad sinks into the main surface during polishing in the polishing step. A method for manufacturing a circuit board.

5. A method for manufacturing a substrate according to claim 4, The distance in the thickness direction is, This value is greater than the amount of sinking of the aforementioned polishing pad. A method for manufacturing a circuit board.

6. A substrate having a main surface and side surfaces, The outer periphery of the substrate, which is the boundary between the main surface and the side surface, is provided with a chamfered portion in which at least one of an inclined surface and a curved surface is formed. The chamfered portion is, A first chamfered portion is formed on the outer periphery of the substrate, wherein the inclined surface is in contact with the main surface and the angle it makes with the main surface is a first inclination angle, or the curved surface is in contact with the main surface and the angle it makes with the main surface is a first inclination angle, The present invention includes a second chamfered portion, which is in contact with the first chamfered portion and the side surface, and has an inclined surface formed thereon, where the angle between the first chamfered portion and the main surface is a second inclination angle greater than the first inclination angle, or a second chamfered portion, which is in contact with the first chamfered portion and the side surface, and has a curved surface formed thereon, where the angle between the tangent line drawn from the point of contact with the first chamfered portion and the main surface is a second inclination angle greater than the first inclination angle. substrate.

Images