Method for machining ceramic capacitor board

Abstract

To provide a method for machining a ceramic capacitor board which can suppress exfoliation of an electrode layer and generation of burrs.SOLUTION: A method for machining a ceramic capacitor board comprises: a half-cut groove formation step of positioning a cutting blade 40 on a first surface 2a and forming half-cut grooves 62 with the depth of substantially 1 / 2 of the thickness of the ceramic capacitor board 2 at an interval corresponding to a size of a chip capacitor; an outer periphery exposure groove formation step of positioning the cutting blade 40 on an outer periphery of a second surface 2b, cutting the outer periphery to expose, from the second surface 2b, the half-cut grooves 62 formed in the first surface 2a, to form an outer periphery exposure groove 62'; a position detection step of imaging, from the second surface 2b side, one pair of outer periphery exposure groove 62' corresponding to the half-cut grooves 62, and detecting corresponding positions to be divided; and a division step of positioning the cutting blade 40 at the positions detected by the position detection step, and forming grooves with the depth reaching the half-cut grooves 62, to divide a ceramic capacitor board 2 into chip capacitors.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a method for processing a ceramic capacitor substrate having electrode films laminated on a first surface and an opposite second surface. [Background technology]

[0002] A wafer having a plurality of devices such as ICs and LSIs formed on its surface along division lines is divided into individual device chips by a cutting machine equipped with a rotatable cutting blade, and each of the divided device chips is used in electrical equipment such as mobile phones and personal computers.

[0003] The present applicant has also proposed a technique for dividing a ceramic capacitor substrate into individual chip capacitors (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-133375 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, this technology involves irradiating a laser beam to form a splitting point and then applying an external force to split the ceramic capacitor substrate into individual chip capacitors. In ceramic capacitor substrates which have electrode films laminated on the front and back sides, problems can arise such as scattering of debris, peeling of the electrode film, and the generation of burrs, which reduces the quality of the chip capacitors.

[0006] An object of the present invention is to provide a method for processing a ceramic capacitor substrate, which can prevent peeling of an electrode film and the generation of burrs. [Means for solving the problem]

[0007] According to the present invention, there is provided the following method for processing a ceramic capacitor substrate, which solves the above-mentioned problems. "A method for processing a ceramic capacitor substrate having electrode films laminated on a first surface and an opposite second surface, comprising: a half-cut groove forming step of positioning a cutting blade on the first surface to form half-cut grooves at intervals corresponding to the size of the chip capacitors and to a depth of approximately half the thickness of the ceramic capacitor substrate; a peripheral exposed groove forming step of positioning a cutting blade on the outer periphery of the second surface and cutting the outer periphery to expose the half-cut groove formed on the first surface to the second surface to form a peripheral exposed groove; a position detection step of detecting a position to be divided corresponding to the half-cut groove by capturing an image of the pair of outer circumferential exposed grooves from the second surface side; and a dividing step of positioning a cutting blade at the position detected in the position detection step and forming a groove deep enough to reach the half-cut groove, thereby dividing the ceramic capacitor substrate into chip capacitors.

[0008] Preferably, prior to the outer peripheral exposed groove forming step, a frame unit forming step is included in which the first surface on which the half-cut groove is formed is positioned in an opening of a frame having an opening in the center, and the first surface is integrated with tape to form a frame unit in which the second surface is exposed. Effect of the Invention

[0009] The method for processing a ceramic capacitor substrate of the present invention includes the steps of: A method for processing a ceramic capacitor substrate having electrode films laminated on a first surface and an opposite second surface, comprising the steps of: a half-cut groove forming step of positioning a cutting blade on the first surface to form half-cut grooves at intervals corresponding to the size of the chip capacitors and to a depth of approximately half the thickness of the ceramic capacitor substrate; a peripheral exposed groove forming step of positioning a cutting blade on the outer periphery of the second surface and cutting the outer periphery to expose the half-cut groove formed on the first surface to the second surface to form a peripheral exposed groove; a position detection step of detecting a position to be divided corresponding to the half-cut groove by capturing an image of the pair of outer circumferential exposed grooves from the second surface side; and a dividing process in which a cutting blade is positioned at the position detected in the position detection process and a groove deep enough to reach the half-cut groove is formed to divide the ceramic capacitor substrate into chip capacitors, thereby preventing peeling of the electrode film and the occurrence of burrs. [Brief description of the drawings]

[0010] [Figure 1] (a) A perspective view of a circular ceramic capacitor substrate, (b) a perspective view of a rectangular ceramic capacitor substrate, and (c) a cross-sectional view of the ceramic capacitor substrate shown in (a) or (b). [Diagram 2] FIG. [Diagram 3] Schematic diagram showing the state in which a protective tape is attached to the ceramic capacitor substrate shown in FIG. 1(a). [Figure 4] FIG. 4 is a schematic diagram showing a state in which the ceramic capacitor substrate shown in FIG. 3 is held on a chuck table. [Diagram 5] FIG. 4(a) is a schematic diagram showing a half-cut groove forming step, and FIG. 4(b) is a cross-sectional view of a ceramic capacitor substrate in which a half-cut groove has been formed. [Figure 6] FIG. [Figure 7] FIG. 4A is a schematic diagram showing a peripheral exposed groove forming step, and FIG. 4B is a cross-sectional view of the outer periphery of a ceramic capacitor substrate in which a peripheral exposed groove has been formed. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 1 is a perspective view of a ceramic capacitor substrate divided into chip capacitors. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for processing a ceramic capacitor substrate according to the present invention will be described with reference to the drawings.

[0012] (Ceramic capacitor substrate 2) FIG. 1 shows a ceramic capacitor substrate 2 (hereinafter, sometimes simply referred to as "substrate 2") to be processed by the method of the present invention. The substrate 2 may be circular as shown in FIG. 1(a) or rectangular as shown in FIG. 1(b). An electrode film is laminated on each of a first surface 2a and a second surface 2b on the opposite side of the substrate 2. In this embodiment, as shown in FIG. 1(c), two layers of electrode films 6 and 8 are laminated on both sides of a ceramic layer 4 as a main part of the substrate 2. The material of the substrate 2 is, for example, a metal ceramic sintered body for the ceramic layer 4, nickel for the electrode film 6 on the ceramic layer 4 side (inside), and copper for the outer electrode film 8. The thickness of each layer is, for example, about 400 μm for the ceramic layer 4, about 5 μm for the electrode film 6 on the ceramic layer 4 side (inside), and about 50 μm for the outer electrode film 8. In the following, an example of processing a circular substrate 2 will be described.

[0013] (Half-cut groove forming process) In this embodiment, first, a half-cut groove forming process is performed in which a cutting blade is positioned on the first surface 2a and half-cut grooves are formed to a depth of approximately 1 / 2 the thickness of the ceramic capacitor substrate 2 at intervals corresponding to the size of the chip capacitor.

[0014] The half-cut groove forming step can be performed, for example, by using a cutting device 10 shown in Fig. 2. The cutting device 10 includes a holding means 12 for holding the substrate 2, a cutting means 14 for cutting the substrate 2 held by the holding means 12, and a feed means 16 for moving the holding means 12 and the cutting means 14 relatively.

[0015] (Holding means 12) The holding means 12 includes an X-axis movable plate 20 supported on the upper surface of the base 18 so as to be movable in the X-axis direction, a support column 22 fixed to the upper surface of the X-axis movable plate 20, and a cover plate 24 fixed to the upper end of the support column 22. A circular opening 24a is formed in the cover plate 24, and a chuck table 26 extending upward through the circular opening 24a is rotatably attached to the upper end of the support column 22. A plurality of clamps 28 are arranged on the periphery of the chuck table 26 at intervals in the circumferential direction.

[0016] A circular suction chuck 30 is disposed on the upper end portion of the chuck table 26. The suction chuck 30 is formed from a porous material such as porous ceramics. The suction chuck 30 is connected to suction means (not shown). In the holding means 12, the suction means generates a suction force on the upper surface of the suction chuck 30, and the substrate 2 placed on the upper surface of the chuck table 26 is sucked and held. The chuck table 26 is rotated by a motor (not shown) built into the support 22.

[0017] The X-axis direction is the direction indicated by the arrow X in Fig. 1. The Y-axis direction indicated by the arrow Y in Fig. 1 is the direction perpendicular to the X-axis direction, and the Z-axis direction indicated by the arrow Z in Fig. 1 is the up-down direction perpendicular to the X-axis and Y-axis directions. The XY plane defined by the X-axis and Y-axis directions is substantially horizontal.

[0018] (Cutting means 14) The cutting means 14 includes a Y-axis movable body 32 supported on the upper surface of the base 18 so as to be movable in the Y-axis direction, and a Z-axis movable body 34 supported by the Y-axis movable body 32 so as to be movable in the Z-axis direction. A spindle housing 36 extending in the Y-axis direction is attached to the Z-axis movable body 34. A spindle 38 extending in the Y-axis direction is rotatably supported by the spindle housing 36. An annular cutting blade 40 is fixed to the tip of the spindle 38. In addition, an imaging means 42 is disposed at a distance from the cutting blade 40 in the X-axis direction, and the imaging means 42 is supported by the spindle housing 36.

[0019] (Feeding means 16) The feed means 16 includes an X-axis feed means 44 that moves the chuck table 26 in the X-axis direction, a Y-axis feed means 46 that moves the cutting blade 40 in the Y-axis direction, and a Z-axis feed means 48 that moves the cutting blade 40 in the Z-axis direction.

[0020] (X-axis feed means 44) The X-axis feed means 44 has a ball screw 50 connected to the X-axis movable plate 20 and extending in the X-axis direction, and a motor 52 that rotates the ball screw 50. The X-axis feed means 44 converts the rotational motion of the motor 52 into linear motion using the ball screw 50 and transmits it to the X-axis movable plate 20, moving the X-axis movable plate 20 in the X-axis direction along a pair of X-axis guide rails 18a provided on the base 18. This causes the chuck table 26 to move in the X-axis direction.

[0021] (Y-axis feed means 46) The Y-axis feed means 46 has a ball screw 54 connected to the Y-axis movable body 32 and extending in the Y-axis direction, and a motor 56 that rotates the ball screw 54. The Y-axis feed means 46 converts the rotational motion of the motor 56 into linear motion using the ball screw 54 and transmits it to the Y-axis movable body 32, moving the Y-axis movable body 32 in the Y-axis direction along a pair of Y-axis guide rails 18b provided on the base 18. This causes the cutting blade 40 to move in the Y-axis direction.

[0022] (Z-axis feed means 48) The Z-axis feed means 48 has a ball screw (not shown) that is connected to the Z-axis movable body 34 and extends in the Z-axis direction, and a motor 58 that rotates the ball screw. The Z-axis feed means 48 converts the rotational motion of the motor 58 into linear motion using the ball screw and transmits it to the Z-axis movable body 34, and moves the Z-axis movable body 34 in the Z-axis direction along a pair of guide rails 32a (only one of which is shown) attached to the Y-axis movable body 32. This causes the cutting blade 40 to move in the Z-axis direction.

[0023] In the half-cut groove forming process, first, the substrate 2 is held on the chuck table 26. To prevent damage to the second surface 2b that is to come into contact with the suction chuck 30, a protective tape 60 is attached to the second surface 2b (see FIG. 3). Next, as shown in FIG. 4, the substrate 2 is placed on the chuck table 26 with the protective tape 60 side facing downward, and then the suction means is operated to generate a suction force on the upper surface of the suction chuck 30. In this manner, the substrate 2 is suction-held on the chuck table 26.

[0024] After the substrate 2 is held on the chuck table 26, the cutting blade 40 forms a half-cut groove on the first surface 2a. First, the imaging means 42 images the substrate 2, and the positional relationship between the substrate 2 and the cutting blade 40 is adjusted based on the image of the substrate 2 captured by the imaging means 42. Next, as shown in FIG. 5(a), the cutting blade 40 rotates at high speed in the R1 direction and cuts the cutting edge of the cutting blade 40 from the first surface 2a to a depth of approximately 1 / 2 the thickness of the substrate 2, and the chuck table 26 is moved in the X-axis direction relative to the cutting blade 40. Also, cutting water is supplied to the portion where the cutting edge of the cutting blade 40 is to be cut. This forms a linear half-cut groove 62 extending in the X-axis direction. As shown in FIG. 5(b), when the thickness of the substrate 2 including the electrode films 6 and 8 is 510 μm, the depth of the half-cut groove 62 may be, for example, about 260 μm.

[0025] Then, the cutting blade 40 is indexed and fed in the Y-axis direction relative to the chuck table 26 by an interval corresponding to the size of the chip capacitor, while repeatedly forming the half-cut grooves 62. After that, the chuck table 26 is rotated 90 degrees, and the formation of the half-cut grooves 62 is repeated while indexing and feeding, thereby forming the half-cut grooves 62 in a lattice pattern on the first surface 2a.

[0026] In the half-cut groove forming process, the electrode films 6, 8 on the first surface 2a side are cut, but the electrode films 6, 8 on the second surface 2b side are not cut. Therefore, an external force caused by cutting acts on the electrode films 6, 8 on the first surface 2a side in a direction pressing them against the ceramic layer 4 of the substrate 2, but does not act on the electrode films 6, 8 on the second surface 2b side in a direction peeling them off from the ceramic layer 4. Therefore, peeling of the electrode films 6, 8 and the generation of burrs can be suppressed.

[0027] (Frame unit forming process) After carrying out the half-cut groove forming process, a frame unit forming process is carried out in which the first surface 2a, in which the half-cut groove 62 is formed, is positioned in an opening of a frame having an opening in the center, and the first surface 2a is integrated with tape to form a frame unit in which the second surface 2b is exposed.

[0028] In the frame unit formation step, a frame 64 as shown in Fig. 6 is prepared. The frame 64 is ring-shaped, and a circular opening 64a capable of accommodating the substrate 2 is provided in the center of the frame 64. A circular adhesive tape 66 is attached to the frame 64 so as to cover the opening 64a.

[0029] After preparing the frame 64, the first surface 2a on which the half-cut grooves 62 are formed is attached to the adhesive surface (upper surface in FIG. 6) of an adhesive tape 66. This forms a frame unit 68 in which the frame 64 and the substrate 2 are integrated by the tape 66. After the substrate 2 is attached to the adhesive tape 66, the protective tape 60 is peeled off from the second surface 2b.

[0030] (Outer periphery exposed groove forming process) After carrying out the frame unit forming process, a peripheral exposed groove forming process is carried out in which a cutting blade 40 is positioned on the outer periphery of the second surface 2b and the outer periphery is cut to expose the half-cut groove 62 formed on the first surface 2a to the second surface 2b, thereby forming an outer periphery exposed groove.

[0031] In the outer periphery exposed groove forming process, first, the substrate 2 of the frame unit 68 is sucked and held on the chuck table 26 with the second surface 2b facing upward. Also, the frame 64 of the frame unit 68 is fixed by the clamp 28. Next, the substrate 2 is imaged by the imaging means 42, and the cutting blade 40 is positioned on the outer periphery of the second surface 2b based on the image of the substrate 2. Next, as shown in FIG. 7(a), the cutting edge of the cutting blade 40 rotated at high speed in the R1 direction is cut from the first surface 2a to a depth of approximately 1 / 2 the thickness of the substrate 2, and the chuck table 26 is rotated in the R2 direction relative to the cutting blade 40. Also, cutting water is supplied to the portion where the cutting edge of the cutting blade 40 is to be cut. As a result, the outer periphery of the substrate 2 is cut, and the half-cut groove 62 formed on the first surface 2a is exposed on the second surface 2b, forming the outer periphery exposed groove 62'. The width (diameter dimension) of cutting the outer periphery of the substrate 2 may be about 400 μm, and the depth of cutting may be about 260 μm. The cutting width of the outer periphery of the substrate 2 is exaggerated in Figures 7(a), 9, and 10. If the cutting blade 40 has a width of 100 μm, cutting four times will result in a width of 400 μm, but the cutting blade may be replaced with a cutting blade having a width of, for example, 500 μm and cut once.

[0032] (Position detection process) After the outer periphery exposed groove forming step is performed, a position detecting step is performed in which a pair of corresponding outer periphery exposed grooves 62' are imaged from the second surface 2b side to detect the positions to be divided corresponding to the half-cut grooves 62.

[0033] In the position detection step, first, the positions of the pair of outer periphery exposed grooves 62' are detected. Specifically, as shown in FIG. 8, an image of any outer periphery exposed groove 62' is captured by the imaging means 42, and the position of the captured outer periphery exposed groove 62' is detected. At this time, in order to align the direction of the outer periphery exposed groove 62' with the X-axis direction, the chuck table 26 is rotated to roughly align the groove. Also, as shown in FIG. 8, the captured image may be displayed on the monitor 70 of the cutting device 10. Next, the chuck table 26 is moved in the X-axis direction, and an image of the outer periphery exposed groove 62' located on an extension line in the X-axis direction of the outer periphery exposed groove 62' whose position was detected earlier is captured, and the position of the captured outer periphery exposed groove 62' is detected.

[0034] Once the positions of the pair of outer circumferential exposed grooves 62' have been detected, the chuck table 26 is rotated and aligned with high precision so that the line connecting the pair of outer circumferential exposed grooves 62' coincides with the X-axis direction, thereby determining the line connecting the pair of outer circumferential exposed grooves 62' as the division position corresponding to the half-cut groove 62. Then, from the determined division position and an interval corresponding to the size of the chip capacitor, a plurality of division positions extending parallel to the above-mentioned division position are determined.

[0035] Next, after rotating the chuck table 26 by 90 degrees, a plurality of division positions perpendicular to the previously determined division positions are determined in the same manner as above. In this manner, images of a pair of corresponding outer circumferential exposed grooves 62' are captured from the second surface 2b side, and the division positions corresponding to the lattice-shaped half-cut grooves 62 are detected.

[0036] (splitting process) After the position detection process is performed, a dividing process is performed in which the cutting blade 40 is positioned at the position detected in the position detection process, a groove deep enough to reach the half-cut groove 62 is formed, and the ceramic capacitor substrate 2 is divided into chip capacitors.

[0037] In the dividing step, the cutting blade 40 is positioned at the position to be divided based on the position detected in the position detection step. Next, as shown in Fig. 9, the cutting edge of the cutting blade 40 rotated at high speed in the R1 direction is caused to cut from the second surface 2b to a depth reaching the half-cut groove 62, and the chuck table 26 is moved in the X-axis direction relative to the cutting blade 40. Also, cutting water is supplied to the portion where the cutting edge of the cutting blade 40 is to be cut. As a result, a linear dividing groove 72 extending in the X-axis direction is formed.

[0038] Then, the cutting blade 40 is indexed and fed in the Y-axis direction relative to the chuck table 26 by an amount corresponding to the size of the chip capacitor, while repeatedly forming the dividing grooves 72. Thereafter, the chuck table 26 is rotated 90 degrees, and the forming of the dividing grooves 72 is repeated while indexing and feeding, thereby dividing the ceramic capacitor substrate 2 into chip capacitors as shown in FIG.

[0039] As described above, in the illustrated embodiment, after the half-cut groove 62 is formed on the first surface 2a, the dividing groove 72 is formed from the second surface 2b to the half-cut groove 62. That is, in this embodiment, when the substrate 2 is cut with the cutting blade 40, the electrode films 6, 8 on the upper surface side of the substrate 2 are cut, but the electrode films 6, 8 on the lower surface side of the substrate 2 are not cut. Therefore, the external force caused by the cutting acts on the electrode films 6, 8 in a direction to press them against the ceramic layer 4 of the substrate 2, but does not act in a direction to peel them off from the ceramic layer 4 of the substrate 2. Therefore, according to this embodiment, peeling of the electrode films 6, 8 and the generation of burrs can be suppressed. [Explanation of symbols]

[0040] 2: Ceramic capacitor substrate 2a: First side 2b: Second Side 4: Ceramic layer 6: Electrode film (nickel) 8: Electrode film (copper) 40:Cutting blade 62: Half cut groove 62': Outer circumference exposure groove 64: Frame 64a: opening 66: Adhesive tape 68: Frame unit

Claims

1. A method for processing a ceramic capacitor substrate having electrode films laminated on a first surface and an opposite second surface, comprising the steps of: a half-cut groove forming step of positioning a cutting blade on the first surface to form half-cut grooves at intervals corresponding to the size of the chip capacitors and to a depth of approximately half the thickness of the ceramic capacitor substrate; a peripheral exposed groove forming step of positioning a cutting blade on the outer periphery of the second surface and cutting the outer periphery to expose the half-cut groove formed on the first surface on the second surface to form a peripheral exposed groove; a position detection step of detecting a position to be divided corresponding to the half-cut groove by capturing an image of the pair of outer circumferential exposed grooves from the second surface side; a dividing step of positioning a cutting blade at the position detected in the position detecting step and forming a groove deep enough to reach the half-cut groove, thereby dividing the ceramic capacitor substrate into chip capacitors.

2. 2. The method for processing a ceramic capacitor substrate as claimed in claim 1, further comprising, prior to said outer periphery exposing groove forming step, a frame unit forming step of positioning said first surface, in which said half-cut groove is formed, at an opening of a frame having a central opening, and integrating said first surface with said half-cut groove at said opening with tape to form a frame unit in which said second surface is exposed.

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