JP2012114345A - Ceramic multilayer substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic multilayer substrate in which the substrate body is less susceptible to action of the impact or stress from a circuit board, or the like, mounting the ceramic multilayer substrate.SOLUTION: The ceramic multilayer substrate comprises (a) a substrate body including a laminated ceramic layer and having a rectangular main surface 12b on one side in the laminating direction of the ceramic layer, and (b) external electrodes 14 formed on the main surface 12b of the substrate body. All external electrodes 14 are arranged on the inside of a first virtual region 30x overlapping first virtual lines 30a-30d connecting the middle points 22a-22d of adjoining sides 20a-20d of the main surface 12b of the substrate body, or surrounded by the first virtual lines 30a-30d.

Description

  The present invention relates to a ceramic multilayer substrate, and more particularly to a ceramic multilayer substrate in which external electrodes are formed on a rectangular main surface of a substrate body.

  Conventionally, a ceramic multilayer substrate having a substrate body including laminated ceramic layers is used for various electronic components.

  For example, the multilayer ceramic electronic component 101 shown in the cross-sectional view of FIG. 28 constitutes a DC-DC converter. The multilayer ceramic electronic component 101 includes a surface electrode 107 for mounting on a circuit board or the like on one main surface of a substrate body 105 in which a base material layer 102 is sandwiched between surface layers 103 and 104. Inside the base material layer 102, an internal conductor film 106, an interlayer connecting conductor 108, and a coil pattern 109 are formed. A surface-mounted electronic component 110 is mounted via a solder bump 112 on a surface electrode 107 on the other main surface of the substrate body 105, and a surface-mounted electronic component 111 is mounted via a solder 113. The base material layer 102 and the surface layers 103 and 104 of the substrate body 105 are made of a ferrite ceramic (see, for example, Patent Document 1).

International Publication No. 2007/148556

  When an electronic component equipped with a ceramic multilayer board is mounted on a circuit board or the like, if the impact or stress from the circuit board or the like is applied to the board body of the ceramic multilayer board, the board body of the ceramic multilayer board is deformed or destroyed. Sometimes.

  In addition, even in the case where deformation or destruction does not occur, especially in a ferrite substrate in which the ceramic layer of the substrate body is made of ferrite ceramic, when the ferrite substrate is deformed by impact or stress, the permeability in the ferrite substrate changes, The electrical characteristics of the electronic component provided with the ferrite substrate may fluctuate.

  In view of such circumstances, the present invention intends to provide a ceramic multilayer substrate in which impacts and stresses are less likely to act on a substrate body from a circuit substrate on which the ceramic multilayer substrate is mounted.

  In order to solve the above-described problems, the present invention provides a ceramic multilayer substrate configured as follows.

  The ceramic multilayer substrate is formed on (a) a substrate body including a laminated ceramic layer and having a rectangular main surface on one side in a direction in which the ceramic layers are stacked; and (b) the main surface of the substrate body. External electrodes. A first virtual region in which all the external electrodes overlap or are surrounded by a first virtual line segment connecting midpoints of adjacent sides of the main surface of the substrate body. It is arranged inside.

  In the above configuration, the external electrode is disposed in the first virtual region or its vicinity, which is an area half of the main surface of the substrate body. Since the external electrodes are arranged away from the four corners of the main surface of the substrate body, the maximum distance between the external electrodes is shorter than when the external electrodes are also arranged at the four corners of the main surface of the substrate body. Therefore, when a ceramic multilayer substrate is mounted on a circuit board or the like via external electrodes, even if the circuit board or the like is deformed, the ceramic multilayer substrate is more than the case where the external electrodes are also arranged at the four corners of the main surface of the substrate body. The deformation of the substrate body of the substrate is reduced, and the stress acting on the substrate body can be reduced.

  Preferably, all of the external electrodes overlap a second virtual line segment connecting the midpoints of the first virtual line segments adjacent to each other or are surrounded by the second virtual line segment. Located inside the area.

  In this case, the external electrode is disposed in or near the second virtual region, which is a quarter of the main surface of the substrate body. The area where the external electrodes are arranged becomes smaller, and the maximum distance between the external electrodes becomes shorter. Therefore, when the ceramic multilayer substrate is fixed to the circuit board or the like via the external electrode, even if the circuit board or the like is deformed, the deformation of the substrate body of the ceramic multilayer substrate is further reduced, and the stress acting on the substrate body is further increased. Can be small.

  Preferably, the substrate body is cut out at a portion including a corner of the main surface, which is originally rectangular, and a cutout portion which is recessed from the main surface is formed.

  In this case, since the substrate body is cut off at the four corners of the main surface on which the external electrodes are formed, even if the circuit board or the like to which the ceramic multilayer substrate is fixed is deformed, it is difficult to contact the circuit board or the like.

  Preferably, the notch is filled with resin.

  In this case, when the circuit board or the like to which the ceramic multilayer substrate is fixed is deformed, the circuit board or the like comes into contact with the resin filled in the notch and does not come into contact with the board body. Since the resin filled in the notches absorbs stress from the circuit board or the like, the board body is less likely to be stressed.

  Preferably, in the substrate body, a hole is formed in a central portion of the main surface, a recess communicating with the hole is formed, and the recess is filled with a resin.

  In this case, even if stress is applied to the substrate body of the ceramic multilayer substrate due to deformation of the circuit substrate on which the ceramic multilayer substrate is mounted, the resin filled in the recesses absorbs the stress. The body is less likely to be stressed.

  Preferably, the ceramic layer is made of a ferrite ceramic.

  In this case, the present invention can be suitably applied to a ceramic multilayer substrate whose electrical characteristics fluctuate due to deformation of the substrate body.

  According to the present invention, it is difficult for an impact or stress to act on a substrate body from a circuit board or the like on which a ceramic multilayer substrate is mounted.

It is a cross section of a ceramic multilayer substrate. Example 1 It is a bottom view of a ceramic multilayer substrate. (Example 1-1) It is a bottom view of a ceramic multilayer substrate. (Example 1-2) It is a bottom view of a ceramic multilayer substrate. (Example 1-3) It is a bottom view of a ceramic multilayer substrate. (Example 1-4) It is a cross section of a ceramic multilayer substrate. (Example 2) It is a bottom view of a ceramic multilayer substrate. (Example 2-1) It is a bottom view of a ceramic multilayer substrate. (Example 2-2) It is a bottom view of a ceramic multilayer substrate. (Example 2-3) It is a bottom view of a ceramic multilayer substrate. (Example 2-4) It is a bottom view of a ceramic multilayer substrate. (Example 2-5) It is a cross section of a ceramic multilayer substrate. (Example 3) It is a bottom view of a ceramic multilayer substrate. (Example 3-1) It is a bottom view of a ceramic multilayer substrate. (Example 3-2) It is a bottom view of a ceramic multilayer substrate. (Example 3-3) It is a bottom view of a ceramic multilayer substrate. (Example 3-4) It is a bottom view of a ceramic multilayer substrate. (Example 3-5) It is a cross section of a ceramic multilayer substrate. Example 4 It is a bottom view of a ceramic multilayer substrate. (Example 4-1) It is a bottom view of a ceramic multilayer substrate. (Example 4-2) It is a bottom view of a ceramic multilayer substrate. (Example 4-3) It is a bottom view of a ceramic multilayer substrate. (Example 4-4) It is a bottom view of a ceramic multilayer substrate. (Example 4-5) It is a cross section of a ceramic multilayer substrate. (Comparative example) It is a bottom view of a ceramic multilayer substrate. (Comparative example) It is a bottom view of a ceramic multilayer substrate. (Modification 1) It is a bottom view of a ceramic multilayer substrate. (Modification 2) It is sectional drawing of the electronic component provided with the ceramic multilayer substrate. (Conventional example)

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  Example 1 A ceramic multilayer substrate 10 of Example 1 will be described with reference to FIGS. 1 to 5, 26 and 27.

  FIG. 1 is a cross-sectional view of a ceramic multilayer substrate 10 according to the first embodiment. As shown in FIG. 1, in the ceramic multilayer substrate 10, external electrodes 14 for mounting the ceramic multilayer substrate 10 on a circuit board or the like are formed on the lower surface 12b of the substrate body 12 on which the ceramic layers are laminated. Terminal electrodes 15a and 15b are formed on the upper surface 12a of the substrate body 12, and the semiconductor element 2 and the chip-type electronic component 4 are mounted using the terminal electrodes 15a and 15b. The substrate body 12 has a cubic shape. The substrate body 12 has a main surface, that is, an upper surface 12a and a lower surface 12b on both sides in the direction in which the ceramic layers are laminated, and the upper surface 12a and the lower surface 12b have a rectangular shape.

  In addition, it is good also as a structure which does not provide a terminal electrode in the upper surface 12a of the board | substrate body 12, but mounts a semiconductor element, an electronic component, etc. in the board | substrate body 12. FIG.

  For example, the ceramic multilayer substrate 10 is a ferrite substrate in which the ceramic layer of the substrate body 12 is made of ferrite ceramic, and a coil pattern 15 is formed inside the substrate body 12. The coil pattern 15 is electrically connected to the external electrode 14 and the terminal electrodes 15a and 15b by an interlayer connection conductor 11a penetrating the ceramic layer and an internal conductor pattern 11b formed between the ceramic layers. Thereby, an electric circuit including a coil (inductor) is formed inside the substrate body 12.

  2 to 5 are bottom views of the ceramic multilayer substrate 10. As shown in FIGS. 2 to 5, the external electrode 14 is formed on the lower surface 12 b of the substrate body 12 in various modes.

  In Example 1-1 shown in FIG. 2, all the external electrodes 14 are connected to the midpoints 22a and 22b between the adjacent sides 20a and 20b, 20b and 20c, 20c and 20d, and 20d and 20a of the lower surface 12b of the substrate body. , 22b and 22c, 22c and 22d, and 22d and 22a are formed so as to overlap the first virtual line segments 30a to 30d. Each external electrode 14 has a portion arranged inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d and a portion arranged outside the first virtual region 30x. .

  Note that only some of the external electrodes 14 may overlap the first virtual line segments 30a to 30d, and all the remaining electrodes may be arranged inside the first virtual region 30x.

  In Example 1-2 shown in FIG. 3, all the external electrodes 14 are arranged inside the first virtual region 30x.

  In FIG. 3, the external electrode 14 is disposed inside the first virtual region 30 x along the first virtual line segments 30 a to 30 d. However, as shown in the bottom view of FIG. The external electrode 14 may be arranged on the virtual circle 30y arranged so as to be in contact with one virtual region 30x, or the external electrode 14 may be arranged in a portion not in contact with the first virtual line segments 30a to 30d. Good.

  In Example 1-3 shown in FIG. 4, all the external electrodes 14 are connected to the first virtual lines 30a and 30b, 30b and 30c, 30c and 30d, 30d and 30a, and the midpoints 32a and 32b and 32b. 32c, 32c and 32d, and 32d and 32a are formed so as to overlap the second imaginary line segments 40a to 40d. Each external electrode 14 has a portion arranged inside the second virtual region 30x surrounded by the second virtual line segments 40a to 40d and a portion arranged outside the second virtual region 40x. .

  Note that only some of the external electrodes may overlap the second virtual line segments 40a to 40d, and all the remaining electrodes may be arranged inside the second virtual region 40x.

  In Example 1-4 shown in FIG. 5, all the external electrodes 14 are arranged inside the second virtual region 40x.

  In FIG. 5, the external electrode 14 is arranged inside the second virtual region 40 x along the second virtual line segments 40 a to 40 d, but for example, as shown in the bottom view of FIG. 27, The external electrode 14 may be disposed on the virtual circle 40y disposed so as to be in contact with the second virtual region 40x, or may be disposed on the portion not in contact with the second virtual line segments 40a to 40d. Good.

  As shown in FIGS. 2 and 3, all the external electrodes 14 overlap the first virtual line segments 30a to 30d or are surrounded by the first virtual line segments 30a to 30d. When arranged on the inner side, the external electrode 14 is arranged in the first virtual region 30x, which is half the area of the lower surface 12b of the substrate body 12, or in the vicinity thereof. Since the external electrodes 14 are arranged away from the four corners of the lower surface 12b of the substrate body 12, compared to the case where the external electrodes 14 are also arranged at the four corners of the lower surface 12b of the substrate body 12, as will be described later, The maximum distance between the external electrodes 14 is shortened. Therefore, when the ceramic multilayer substrate 10 is mounted on a circuit board or the like via the external electrodes 14, even if the circuit board or the like is deformed, the external electrodes 14 are arranged at the four corners of the lower surface 12b of the substrate body 12. The deformation of the substrate body 12 of the ceramic multilayer substrate 10 is reduced, and the stress acting on the substrate body 12 can be reduced.

  As shown in FIGS. 4 and 5, all the external electrodes 14 overlap the second virtual line segments 40a to 40d or are surrounded by the second virtual line segments 40a to 40d. When arranged on the inner side, the external electrode 14 is arranged at or near the second virtual region 40x, which is a quarter of the area of the lower surface 12b of the substrate body 12. Since the area where the external electrodes 14 are arranged becomes smaller and the maximum distance between the external electrodes 14 becomes shorter, when the ceramic multilayer substrate 10 is fixed to the circuit board or the like via the external electrodes 14, the circuit board or the like Even if deformed, the deformation of the substrate main body 12 of the ceramic multilayer substrate 10 becomes smaller, and the stress acting on the substrate main body 12 can be further reduced.

  Example 2 A ceramic multilayer substrate 10a of Example 2 will be described with reference to FIGS.

  The ceramic multilayer substrate 10a of Example 2 is configured in substantially the same manner as the ceramic multilayer substrate 10 of Example 1. In the following description, the same reference numerals are used for the same parts as those in the first embodiment, and differences from the first embodiment will be mainly described.

  FIG. 6 is a cross section of the ceramic multilayer substrate 10a of the second embodiment. As shown in FIG. 6, in the ceramic multilayer substrate 10a, cutout portions 16, 16a, 16b that are recessed from the lower surfaces 12c, 12d, 12e are formed on the lower surfaces 12c, 12d, 12e side of the substrate body 12s on which the ceramic layers are laminated. Has been.

  7 to 11 are bottom views of the ceramic multilayer substrate 10a. As shown in FIGS. 7 to 11, the lower surface 12c, 12d, 12e side of the substrate body 12s is formed in various modes. Note that the first virtual line segments 30a to 30d, the first virtual area 30x, the second virtual line segments 40a to 40d, and the second virtual area 40x shown in FIGS. Is defined for a bottom surface that is rectangular.

  In Example 2-1, shown in FIG. 7, rectangular cutouts 16 are formed in portions including corners 12u to 12x of the lower surface, which is originally rectangular, and the lower surface 12c of the substrate main body is a cross. It is formed into a shape. All the external electrodes 14 are formed on the lower surface 12c of the substrate body so as to overlap the first virtual line segments 30a to 30d. Each external electrode 14 has a portion arranged inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d and a portion arranged outside the first virtual region 30x. . The notch 16 is formed outside the first virtual region 30x.

  Note that only some of the external electrodes 14 may overlap the first virtual line segments 30a to 30d, and all the remaining electrodes may be arranged inside the first virtual region 30x.

  In Example 2-2 shown in FIG. 8, right-sided triangular cutouts 16 a are formed along the first virtual line segments 30 a to 30 d in the portions including the corners 12 u to 12 x of the lower surface, which is originally rectangular, of the substrate body. The lower surface of the substrate body is formed in a substantially rhombus shape. All the external electrodes 14 are formed on the lower surface 12d of the substrate body so as to be disposed inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d. The notch 16a is formed outside the first virtual region 30x.

  In Example 2-3 shown in FIG. 9, a rectangular notch 16 is formed in a portion including corners 12u to 12x of the lower surface, which is originally rectangular, and the lower surface 12c of the substrate main body has a cross shape. Is formed. All the external electrodes 14 are formed on the lower surface 12c of the substrate body so as to be disposed inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d.

  In Example 2-4 shown in FIG. 10, the frame is formed so as to include the corners 12u to 12x of the bottom surface of the substrate body, which is originally rectangular, along the sides 20a to 20d of the bottom surface of the substrate body. A notch 16b is formed. A bottom surface 12e of the substrate body is formed in a rectangular shape inside the notch 16b. On the lower surface 12e of the substrate main body, all the external electrodes 14 are located inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d, along the first virtual line segments 30a to 30d. It is formed so as to be arranged in a substantially ring shape.

  In Example 2-5 shown in FIG. 11, the frame is formed so as to include the corners 12u to 12x of the bottom surface of the substrate body, which is originally rectangular, along the sides 20a to 20d of the bottom surface of the substrate body. A notch 16b is formed. A bottom surface 12e of the substrate body is formed in a rectangular shape inside the notch 16b. On the lower surface 12e of the substrate body, all the external electrodes 14 are arranged inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d in parallel with the notches 16b and in a lattice pattern. Is formed.

  The ceramic multilayer substrate 10a according to the second embodiment is formed so that all the external electrodes 14 overlap the first imaginary line segments 30a to 30d or are arranged inside the first imaginary region 30x. When the multilayer substrate 10a is fixed to the circuit board or the like via the external electrode 14, the stress acting on the substrate body 12s can be reduced even if the circuit board or the like is deformed.

  Further, the cutout portions 16, 16a, 16b are formed on the lower surface 12c, 12d, 12e side of the substrate body 12s, and the four corners of the lower surface 12c, 12d, 12e, which are originally rectangular, are cut out. The substrate main body 12s is unlikely to contact the circuit board or the like even if the circuit board or the like to which the ceramic multilayer substrate 10a is fixed is deformed.

  <Example 3> The ceramic multilayer substrate 10b of Example 3 will be described with reference to FIGS.

  FIG. 12 is a cross section of the ceramic multilayer substrate 10b of Example 3. As shown in FIG. 12, the ceramic multilayer substrate 10b according to the third embodiment is similar to the ceramic multilayer substrate 10a according to the second embodiment. The cutout portions 16 are formed on the lower surfaces 12c, 12d, and 12e of the substrate body 12s on which the ceramic layers are laminated. 16a and 16b are formed.

  Unlike the ceramic multilayer substrate 10a of the second embodiment, the ceramic multilayer substrate 10b of the third embodiment is filled with the resin 18, 18a, 18b in the notches 16, 16a, 16b, and the surface 18s of the resin 18, 18a, 18b has a surface 18s. It is formed so as to be included in the same plane as the lower surfaces 12c, 12d and 12e of the substrate body 12s.

  13 to 17 are bottom views of the ceramic multilayer substrate 10b. As shown in FIGS. 13-17, the lower surface 12c, 12d, 12e side of the board | substrate body 12s is formed in various aspects.

  In Example 3-1, shown in FIG. 13, rectangular cutouts 16 are formed in portions of the substrate body including the corners of the lower surface, which is originally rectangular, and the lower surface 12c of the substrate body is formed in a cross shape. Has been. Each notch 16 is filled with resin 18. All the external electrodes 14 are formed on the lower surface 12c of the substrate body so as to overlap the first virtual line segments 30a to 30d. Each external electrode 14 has a portion arranged inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d and a portion arranged outside the first virtual region 30x. .

  Note that only some of the external electrodes 14 may overlap the first virtual line segments 30a to 30d, and all the remaining electrodes may be arranged inside the first virtual region 30x.

  In Example 3-2 shown in FIG. 14, a rectangular notch 16 is formed on the lower surface 12c side of the substrate body, as in Example 3-1 of FIG. 13, and the lower surface 12c of the substrate body is formed in a cross shape. Has been. Each notch 16 is filled with resin 18.

  However, unlike the embodiment 3-1 of FIG. 13, all the external electrodes 14 are located on the inner surface of the first virtual region 30x surrounded by the first virtual line segments 30a to 30d on the lower surface 12c of the substrate body. It is formed to be arranged.

  In Example 3-3 shown in FIG. 15, right-angled triangular cutout portions 16 a are formed along the first virtual line segments 30 a to 30 d in portions including the corners of the lower surface, which is originally rectangular, of the substrate body. The lower surface 12d of the substrate body is formed in a substantially rhombus shape. Each notch 16a is filled with resin 18a. All the external electrodes 14 are formed on the lower surface 12d of the substrate body so as to be disposed inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d.

  In Example 3-4 shown in FIG. 16, a frame-shaped notch 16b is formed along each side of the bottom surface of the substrate body, which is originally rectangular, so as to include the corners of the bottom surface, which is originally rectangular. Yes. A bottom surface 12e of the substrate body is formed in a rectangular shape inside the notch 16b. The notch 16b is filled with a resin 18b. On the lower surface 12e of the substrate main body, all the external electrodes 14 are located inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d, along the first virtual line segments 30a to 30d. It is formed so as to be arranged in a substantially ring shape.

  In Example 3-5 shown in FIG. 17, a frame-like notch 16b is formed as in Example 3-4 in FIG. 16, and the lower surface 12e of the substrate body is formed in a rectangular shape. Each notch 16b is filled with resin 18b. All the external electrodes 14 are formed on the inner surface of the first virtual region 30x on the lower surface 12e of the substrate body.

  However, unlike Example 3-4 in FIG. 16, the external electrodes 14 are formed so as to be arranged in a lattice pattern along the notches 16.

  The ceramic multilayer substrate 10b according to the third embodiment is formed so that all the external electrodes 14 overlap the first imaginary line segments 30a to 30d or are arranged inside the first imaginary region 30x. When the multilayer substrate 10b is fixed to the circuit board or the like via the external electrode 14, even if the circuit board or the like is deformed, the stress acting on the substrate body 12s can be reduced.

  Further, in the ceramic multilayer substrate 10b, the notches 16, 16a, 16b are formed in the lower surfaces 12c, 12d, 12e of the substrate body 12s, and the notches 16, 16a, 16b are filled with the resins 18, 18a, 18b. When the circuit board or the like to which the ceramic multilayer substrate 10b is fixed is deformed, the circuit board or the like comes into contact with the resins 18, 18a and 18b filled in the notches 16, 16a and 16b, and does not come into contact with the board body 12s. . Since the resin 18, 18a, 18b filled in the notches 16, 16a, 16b absorbs stress from the circuit board or the like, the board body 12s is less likely to be stressed. Therefore, the stress acting on the substrate body 12s can be reduced.

  Further, the drop strength of the ceramic multilayer substrate 10b is improved by the resins 18, 18a, 18b filled in the notches 16, 16a, 16b.

  Example 4 A ceramic multilayer substrate 10c of Example 4 will be described with reference to FIGS.

  FIG. 18 is a cross section of the ceramic multilayer substrate 10c of Example 4. As shown in FIG. 18, in the ceramic multilayer substrate 10c of Example 4, notches 16, 16a, and 16b are formed on the lower surface 12f to 12i side of the substrate body 12t on which the ceramic layers are laminated, as in Example 3. The notches 16, 16a, 16b are filled with the resins 18, 18a, 18b, and the surfaces 18s of the resins 18, 18a, 18b are formed so as to be included in the same plane as the lower surfaces 12f-12i of the substrate body 12t. .

  Unlike the third embodiment, the substrate body 12t has a hole 12p formed at the center of the lower surfaces 12f to 12i, and recesses 17, 17a to 17d communicating with the hole 12p. The recesses 17, 17a to 17d are filled with resin 19, 19a to 19d. The surfaces 19s of the resins 19, 19a to 19d are formed so as to be included in the same plane as the lower surfaces 12f to 12i of the substrate body 12t.

  19 to 23 are bottom views of the ceramic multilayer substrate 10c. As shown in FIGS. 19-23, the lower surface 12f-12i side of the ceramic multilayer substrate 10c is formed in various modes.

  In Example 4-1 shown in FIG. 19, rectangular cutout portions 16 are respectively formed in the portions including the corners of the lower surface, which is originally rectangular, and the outer shape of the lower surface 12 f of the substrate main body is a cross shape. Is formed. Each notch 16 is filled with resin 18. All the external electrodes 14 are formed on the lower surface 12f of the substrate body so as to overlap the first virtual line segments 30a to 30d. Each external electrode 14 has a portion arranged inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d and a portion arranged outside the first virtual region 30x. .

  A concave portion 17 is formed in a central portion on the lower surface 12 f side of the substrate body, and the concave portion 17 is filled with a resin 19. The recess 17 is surrounded by the external electrode 14.

  In Example 4-2 shown in FIG. 20, rectangular cutout portions 16 are respectively formed in the portions including the corners of the lower surface, which is originally rectangular, and the outer shape of the lower surface 12 g of the substrate main body is a cross shape. Is formed. Each notch 16 is filled with resin 18. All the external electrodes 14 are formed on the lower surface 12g of the substrate body so as to be disposed inside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d.

  A concave portion 17a is formed in a central portion on the lower surface 12g side of the substrate body 12t, and the concave portion 17a is filled with a resin 19a. The recess 17 a is surrounded by the external electrode 14.

  In Example 4-3 shown in FIG. 21, right-angled triangular notches 16a are formed along the first imaginary line segments 30a to 30d in the portions including the corners of the lower surface, which is originally rectangular, of the substrate body. The lower surface 12h of the substrate body is formed in a substantially rhombus shape. Each notch 16a is filled with resin 18a. On the lower surface 12h of the substrate main body, all the external electrodes 14 are located inside the first virtual area 30x surrounded by the first virtual line segments 30a to 30d, along the first virtual line segments 30a to 30d. It is formed to be arranged.

  A concave portion 17b is formed in a central portion on the lower surface 12h side of the substrate body, and the concave portion 17b is filled with a resin 19b. The recess 17 b is surrounded by the external electrode 14.

  In Example 4-4 shown in FIG. 22, the frame-shaped notch 16b is formed so as to include the corners of the bottom surface of the substrate body, which is originally rectangular, along each side of the bottom surface of the substrate body, which is originally rectangular. Is formed. The notch 16b is filled with a resin 18b. A bottom surface 12i of the substrate body is formed inside the notch 16b. The outer shape of the lower surface 12i of the substrate body is a rectangular shape.

  On the lower surface 12i of the substrate body, all the external electrodes 14 overlap the second virtual line segments 30a to 30d inside the first virtual area 30x surrounded by the first virtual line segments 30a to 30d. Is formed. Each external electrode 14 has a portion disposed inside the second virtual region 40x surrounded by the second virtual line segments 40a to 40d and a portion disposed outside the second virtual region 40x. .

  A concave portion 17c is formed in the central portion on the lower surface 12i side of the substrate body, and the concave portion 17c is filled with a resin 19c. The concave portion 17 c is surrounded by the external electrode 14.

  In Example 4-5 shown in FIG. 23, the frame-shaped notch portion 16b is formed along each side of the lower surface of the substrate body which is originally rectangular so as to include the corners of the lower surface which is originally rectangular. Yes. The notch 16b is filled with a resin 18b.

  On the lower surface 12i of the substrate main body, all the external electrodes 14 are disposed inside the second virtual region 40x surrounded by the second virtual line segments 40a to 40d, along the second virtual line segments 40a to 40d. It is formed to be arranged.

  A concave portion 17d is formed in the central portion on the lower surface 12i side of the substrate body, and the concave portion 17d is filled with a resin 19d. The recess 17 d is surrounded by the external electrode 14.

  The ceramic multilayer substrate 10c according to the fourth embodiment is formed so that all the external electrodes 14 overlap the first imaginary line segments 30a to 30d or are arranged inside the first imaginary region 30x. When the multilayer substrate 10c is fixed to the circuit board or the like via the external electrode 14, even if the circuit board or the like is deformed, the stress acting on the substrate body 12t can be reduced.

  Further, since the notches 16, 16a, 16b are formed on the lower surface 12f-12i side of the substrate body 12t and the notches 16, 16a, 16b are filled with the resins 18, 18a, 18b, the ceramic multilayer substrate 10c is fixed. When the circuit board or the like is deformed, the circuit board or the like comes into contact with the resins 18, 18a and 18b filled in the notches 16, 16a and 16b, and does not come into contact with the board body 12t. Since the resin 18, 18a, 18b filled in the notches 16, 16a, 16b absorbs stress from the circuit board or the like, the board main body 12t is hardly stressed. Therefore, the stress acting on the substrate body 12t can be reduced.

  Furthermore, since the concave portions 17, 17a to 17d are formed in the central portion on the lower surface 12f to 12i side of the substrate main body 12t, and the concave portions 17, 17a to 17d are filled with the resins 19, 19a to 19d, the ceramic multilayer substrate 10c is formed. Even if stress is applied to the substrate body 12t of the ceramic multilayer substrate 10c due to deformation of the mounted circuit board or the like, the resins 19, 19a to 19d in the recesses 17, 17a to 17d absorb the stress. Thereby, it becomes difficult to apply stress to the substrate body 12t of the ceramic multilayer substrate 10c.

  The drop strength of the substrate body 12t of the ceramic multilayer substrate 10c is improved by the resins 18, 18a, 18b, 19, 19a-19d filled in the notches 16, 16a, 16b and the recesses 17, 17a-17d.

  Comparative Example FIG. 24 is a cross-sectional view of a ceramic multilayer substrate 10x of a comparative example. FIG. 25 is a bottom view of the ceramic multilayer substrate 10x of the comparative example.

  As shown in FIGS. 24 and 25, external electrodes 14 are formed on the rectangular lower surface 12 b of the substrate body 12 on which the ceramic layers are laminated so as to be arranged along the sides 20 a to 20 d of the lower surface 12 b. ing. The external electrodes 14 are also formed at the four corners of the lower surface 12b, that is, near the corners 12u to 12x of the lower surface 12b. The external electrodes 14 formed at the four corners of the lower surface 12b are disposed outside the first virtual region 30x surrounded by the first virtual line segments 30a to 30d.

  <Production Example> The ceramic multilayer substrates of the above examples and comparative examples can be produced by the following method.

First, a ceramic green sheet to be a ceramic layer of the substrate body is prepared. Ferric oxide (Fe ₂ O ₃ ), zinc oxide (ZnO), nickel oxide (NiO), and copper oxide (CuO) are mixed at a predetermined ratio as the raw material powder of the ferrite ceramic constituting the ceramic layer. In this case, for example, a ferrite ceramic having a relative permeability of 150 at 1 MHz can be obtained. A binder, a plasticizer, a wetting agent, a dispersing agent and the like are added to the ferrite ceramic raw material powder to form a slurry, which is formed into a sheet shape to obtain a ceramic green sheet. In the case of producing the configurations of Examples 2 to 4 (ceramic multilayer substrate in which notches and recesses are formed in the substrate body), notches and through holes are formed in portions corresponding to the notches and recesses of the ceramic green sheet. Form it.

  Next, a through hole is formed in the ceramic green sheet, and the through hole is filled with a conductive paste, thereby forming an unsintered interlayer connection conductor. Moreover, an unsintered internal conductor pattern and a surface conductor pattern are formed by printing a conductive paste on the ceramic green sheet. The conductive metal contained in the conductive paste for forming the inner conductor pattern, the surface conductor pattern, and the interlayer connection conductor is preferably composed mainly of silver or silver / palladium.

  Next, the ceramic green sheets are laminated and pressure-bonded to obtain an unsintered ceramic laminate. When producing the ceramic multilayer substrates of Examples 2 to 4, ceramic green sheets may be laminated one by one in order, and a ceramic laminate may be produced, or a portion (a lower portion of the substrate) provided with notches and recesses. A ceramic laminate may be produced by producing a laminate in which portions not provided (the upper portion of the substrate) are separately laminated and then crimping them.

  In the case where a plurality of ceramic multilayer substrates are simultaneously produced in an aggregated state, a ceramic laminate in an aggregated state including a portion that becomes a plurality of ceramic multilayer substrates is produced. In this case, a dividing groove is formed in the ceramic laminate so that it can be easily divided after firing.

  Next, the unsintered ceramic laminate is fired to obtain a sintered ceramic laminate.

  In Examples 3 and 4, when the resin is embedded in the notches and the recesses, the resin is applied to the notches and the recesses of the sintered ceramic laminate by a method of dispensing or vacuum printing. As the resin, for example, an epoxy resin can be used.

  Next, the surface conductor pattern exposed on the surface of the ceramic laminate is plated. Specifically, a nickel plating film and a tin plating film are sequentially formed by electroplating. The plating process may be performed by electroless plating. In the case of electroless plating, for example, a nickel plating film and a gold plating film are sequentially formed.

  Next, a semiconductor element or an electronic component is mounted on the upper surface of the ceramic laminate. For example, the semiconductor element is mounted by flip chip bonding. Alternatively, a solder paste is applied to the terminal electrode on the upper surface of the ceramic laminate, and surface-mounted electronic components are mounted, and then passed through a reflow furnace.

  In the case where a plurality of ceramic multilayer substrates are simultaneously produced in an aggregated state, a ceramic laminate on which semiconductor elements and electronic components are mounted is divided along the dividing grooves to obtain pieces of the ceramic multilayer substrate.

  Next, if necessary, a metal cover is attached to the ceramic multilayer substrate to complete the ceramic multilayer substrate.

  In the above description, the dividing grooves are formed in the unsintered ceramic laminate and divided after firing. However, without forming the dividing grooves, the assembled ceramic laminate is separated into individual pieces before the firing step. It may be divided into two and fired. In this case, the individual pieces after firing are plated by, for example, electrolytic plating using a barrel.

  Note that the ferrite ceramic for forming the ceramic layer of the substrate body is not limited to the Fe-Ni-Zn-Cu-based and Fe-Zn-Cu-based compositions described above. For example, Fe-Mn-Zn Other compositions such as a system may be used.

  <Prototype Example> According to the above method, samples of the ceramic multilayer substrate of each Example and Comparative Example were prepared, and the characteristics when the stress was applied and not applied with the sample mounted on the printed board were measured.

  The sample is a DC-DC converter, and all circuit elements are built in the substrate body, and nothing is mounted on the upper surface of the substrate body. The substrate body has an upper and lower surface dimensions of 3 mm × 3 mm and a thickness of 500 μm. The depth of the notch and the recess is 100 μm. The ceramic layer of the substrate body is a ferrite ceramic having a relative permeability of 150 at 1 MHz shown in the production example. The width of the coil pattern built in the substrate body is 200 μm, the thickness of the coil pattern is 10 μm, the coil pattern is 8 turns, and the total length of the coil pattern is 30 mm.

Conversion efficiency η _p (i) when a load of 500 gf is applied to the upper surface of the sample with a 2 mm × 2 mm terminal in a state where the sample is mounted on a printed circuit board, and conversion efficiency η ₀ ( i) was measured while changing the current value i in the range of 1 mA to 100 mA, and the difference in conversion efficiency Δη (i) = η _p (i) −η ₀ (i) was measured. The difference in conversion efficiency when the absolute value is maximum is defined as “change in maximum conversion efficiency”.

  The change in the maximum conversion efficiency (characteristic change) becomes smaller as the stress acting on the substrate body of the sample is smaller.

表１の「外部電極構造」欄の（１）〜（４）は、次の通りである。
（１）外部電極は、それぞれの少なくとも一部分が第１の仮想領域の内側に配置されている。
（２）外部電極は、それぞれの全部部分が第１の仮想領域の内側に配置されている。
（３）外部電極は、それぞれの少なくとも一部分が第２の仮想領域の内側に配置されている。
（４）外部電極は、それぞれの全部部分が第２の仮想領域の内側に電極が配置されている。 Table 1 below shows the measurement results for the samples of Example 1 and the comparative example.

(1) to (4) in the “External electrode structure” column of Table 1 are as follows.
(1) At least a part of each external electrode is arranged inside the first virtual region.
(2) All the external electrodes are arranged inside the first virtual region.
(3) At least a part of each external electrode is disposed inside the second virtual region.
(4) As for the external electrode, the electrode is arrange | positioned inside each 2nd virtual area | region for all the parts.

  From Table 1, it can be seen that the change in the maximum conversion efficiency is smaller in Example 1 than in the comparative example. This is because the distance between the external electrodes is shortened because the external electrodes are moved to the center, and even when stress is applied to the substrate body, the magnetic field is generated by the coil pattern in the ceramic multilayer substrate. This is because the stress applied to the portion is reduced, and the change in the magnetic permeability in the central portion of the substrate body is reduced. It can be seen that the closer the external electrode is to the center, the smaller the characteristic change.

表２の「外部電極構造」欄の（１）〜（５）は、次の通りである。
（１）外部電極は、それぞれの少なくとも一部分が第１の仮想領域の内側に配置されている。
（２）外部電極は、それぞれの全部部分が第１の仮想領域の内側に電極が配置されている。
（３）外部電極は、それぞれの少なくとも一部分が第２の仮想領域の内側に配置されている。
（４）外部電極は、それぞれの全部部分が第２の仮想領域の内側に電極が配置されている。
（５）基板本体に切欠部が形成されている。 Table 2 below shows the measurement results for the samples of Example 2 and the comparative example.

(1) to (5) in the “External electrode structure” column of Table 2 are as follows.
(1) At least a part of each external electrode is arranged inside the first virtual region.
(2) As for the external electrode, each electrode is arranged inside the first virtual region.
(3) At least a part of each external electrode is disposed inside the second virtual region.
(4) As for the external electrode, the electrode is arrange | positioned inside each 2nd virtual area | region for all the parts.
(5) A notch is formed in the substrate body.

  From Table 2, it can be seen that the characteristic change is smaller in Example 2 in which the notch portion is formed on the lower surface side of the substrate main body than in Example 1 (Table 1).

表３の「外部電極構造」欄の（１）〜（７）は、次の通りである。
（１）外部電極は、それぞれの少なくとも一部分が第１の仮想領域の内側に配置されている。
（２）外部電極は、それぞれの全部部分が第１の仮想領域の内側に電極が配置されている。
（３）外部電極は、それぞれの少なくとも一部分が第２の仮想領域の内側に配置されている。
（４）外部電極は、それぞれの全部部分が第２の仮想領域の内側に電極が配置されている。
（５）基板本体の下面側の四隅に、切欠部が形成される。
（６）基板本体の下面側の外縁に沿って枠状の切欠部が形成され、切欠部に樹脂が充填されている。
（７）基板本体の下面側の四隅に切欠部が形成され、切欠部に樹脂が充填されている。 Table 3 below shows the measurement results for the samples of Example 3 and the comparative example.

(1) to (7) in the “External electrode structure” column of Table 3 are as follows.
(1) At least a part of each external electrode is arranged inside the first virtual region.
(2) As for the external electrode, each electrode is arranged inside the first virtual region.
(3) At least a part of each external electrode is disposed inside the second virtual region.
(4) As for the external electrode, the electrode is arrange | positioned inside each 2nd virtual area | region for all the parts.
(5) Cutouts are formed at the four corners on the lower surface side of the substrate body.
(6) A frame-shaped notch is formed along the outer edge on the lower surface side of the substrate body, and the notch is filled with resin.
(7) Cutouts are formed at the four corners on the lower surface side of the substrate body, and the cutouts are filled with resin.

  From Table 3, it can be seen that the characteristic change is smaller in Example 3 in which the notch is filled with resin than in Example 2 (Table 2).

表４の「外部電極構造」欄の（１）〜（８）は、次の通りである。
（１）外部電極は、それぞれの少なくとも一部分が第１の仮想領域の内側に配置されている。
（２）外部電極は、それぞれの全部部分が第１の仮想領域の内側に電極が配置されている。
（３）外部電極は、それぞれの少なくとも一部分が第２の仮想領域の内側に配置されている。
（４）外部電極は、それぞれの全部部分が第２の仮想領域の内側に電極が配置されている。
（５）基板本体の下面側の四隅に、切欠部が形成される。
（６）基板本体の下面側の外縁に沿って枠状の切欠部が形成され、切欠部に樹脂が充填されている。
（７）基板本体の下面側の四隅に切欠部が形成され、切欠部に樹脂が充填されている。
（８）基板本体の下面側の中央部分に凹部が形成され、凹部に樹脂が充填されている。 Table 4 below shows the measurement results for the samples of Example 4 and the comparative example.

(1) to (8) in the “External electrode structure” column of Table 4 are as follows.
(1) At least a part of each external electrode is arranged inside the first virtual region.
(2) As for the external electrode, each electrode is arranged inside the first virtual region.
(3) At least a part of each external electrode is disposed inside the second virtual region.
(4) As for the external electrode, the electrode is arrange | positioned inside each 2nd virtual area | region for all the parts.
(5) Cutouts are formed at the four corners on the lower surface side of the substrate body.
(6) A frame-shaped notch is formed along the outer edge on the lower surface side of the substrate body, and the notch is filled with resin.
(7) Cutouts are formed at the four corners on the lower surface side of the substrate body, and the cutouts are filled with resin.
(8) A recess is formed in the central portion on the lower surface side of the substrate body, and the recess is filled with resin.

  From Table 4, it can be seen that the characteristic change of Example 4 in which the recess is filled with resin is smaller than that of Example 3 (Table 3).

  <Summary> In the ceramic multilayer substrates of Examples 1 to 4 described above, impacts and stresses from a circuit board on which the ceramic multilayer substrate is mounted are less likely to act on the substrate body.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications.

  For example, the present invention can be suitably applied to a ceramic multilayer substrate in which the ceramic layer of the substrate body is made of a ferrite ceramic, but is not limited thereto.

10, 10a to 10c, 10x Ceramic multilayer substrate 11a Interlayer connection conductor 11b Inner conductor pattern 12 Substrate body 12a Upper surface 12b to 12i Lower surface 12p Hole 12s, 12t Substrate body 12u to 12x Square 14 External electrode 15 Coil pattern 15a, 15b Terminal electrode 16 , 16a, 16b Notch 17, 17a-17d Recess 18, 18a, 18b Resin 19, 19a-19d Resin 20a-20d Side 22a-22d Middle point 30a-30d First virtual line 30x First virtual region 40a-40d 2nd virtual line 40x 2nd virtual area

Claims (6)

A substrate body including a laminated ceramic layer and having a rectangular main surface on one side in a direction in which the ceramic layers are laminated;
An external electrode formed on the main surface of the substrate body;
In ceramic multilayer substrate with
A first virtual region in which all the external electrodes overlap or are surrounded by a first virtual line segment connecting midpoints of adjacent sides of the main surface of the substrate body. A multilayer ceramic substrate, characterized in that the ceramic multilayer substrate is disposed inside the substrate.   All of the external electrodes overlap the second virtual line segment connecting the midpoints of the first virtual line segments adjacent to each other, or inside the second virtual region surrounded by the second virtual line segment The ceramic multilayer substrate according to claim 1, wherein the ceramic multilayer substrate is disposed on the substrate.   3. The substrate body according to claim 1, wherein a portion including the corner of the main surface, which is originally rectangular, is cut out, and a cutout portion that is recessed from the main surface is formed. Ceramic multilayer substrate.   The ceramic multilayer substrate according to claim 3, wherein the notch is filled with a resin.   5. The substrate body according to claim 1, wherein a hole is formed in a central portion of the main surface, a concave portion communicating with the hole is formed, and the concave portion is filled with a resin. Ceramic multilayer substrate.   The ceramic multilayer substrate according to claim 1, wherein the ceramic layer is made of a ferrite ceramic.

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