Metal parts and ceramic substrates

Abstract

To provide metal components and ceramic substrates that can improve joint reliability in high temperature environments.SOLUTION: The metal component is a columnar metal component having a first main surface and a second main surface opposite the first main surface, and a first groove is formed on the first main surface and a through hole is formed through the first main surface to the second main surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to metal components and ceramic substrates. [Background technology]

[0002] Ceramic substrates have been proposed that include conductive layers, and metal components may be joined to the conductive layers using solder through openings formed in the ceramic substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-212668 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-188389 Summary of the Invention [Problem to be solved by the invention]

[0004] When solder is used to join metal parts to conductive parts located in openings in a circuit board, the flux contained in the solder becomes difficult to volatilize, resulting in a joint layer with many voids in the solder, reducing joint reliability. In particular, when used for long periods in high-temperature environments above 200°C, solder fatigue reduces joint reliability.

[0005] An object of the present disclosure is to provide a metal part and a ceramic substrate that can improve bonding reliability in high-temperature environments. [Means for solving the problem]

[0006] According to one embodiment of the present disclosure, there is provided a columnar metal component having a first main surface and a second main surface opposite to the first main surface, A plurality of radially extending portions extending from the center of the first main surface to the outer edge thereof A first groove is formed, At a position away from the center of the first main surface in a plan view, penetrates from the first main surface to the second main surface MultipleA metal component is provided having a through hole formed therein. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to improve the bonding reliability in a high-temperature environment. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an overview of a ceramic substrate according to a first embodiment. [Figure 2] FIG. 2 is a top view showing the metal part in the first embodiment. [Figure 3] FIG. 2 is a bottom view showing the metal part in the first embodiment. [Figure 4] FIG. 2 is a front view showing the metal part according to the first embodiment. [Figure 5] FIG. 2 is a bottom view showing the first wiring layer. [Figure 6] 1 is a cross-sectional view (part 1) showing a joint structure between a first wiring layer and a metal component in the first embodiment. [Figure 7] 4 is a cross-sectional view (part 2) showing the joint structure between the first wiring layer and the metal component in the first embodiment. FIG. [Figure 8] 10 is a cross-sectional view (part 3) showing the joint structure between the first wiring layer and the metal component in the first embodiment. FIG. [Figure 9] FIG. 10 is a top view showing a metal part according to a second embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a joint structure between a first wiring layer and a metal component in a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that in this specification and drawings, components having substantially the same functional configurations may be denoted by the same reference numerals to avoid redundant description. In this disclosure, the X1-X2 direction, the Y1-Y2 direction, and the Z1-Z2 direction are defined as mutually orthogonal directions. A plane including the X1-X2 direction and the Y1-Y2 direction will be referred to as the XY plane, a plane including the Y1-Y2 direction and the Z1-Z2 direction will be referred to as the YZ plane, and a plane including the Z1-Z2 direction and the X1-X2 direction will be referred to as the ZX plane. For convenience, the Z1-Z2 direction will be defined as the up-down direction, with the Z1 side referred to as the upper side and the Z2 side referred to as the lower side. A planar view refers to viewing an object from the Z1 side, and a planar shape refers to the shape of an object viewed from the Z1 side. However, metal components and ceramic substrates can be used upside down or positioned at any angle.

[0010] (First embodiment) First, a first embodiment will be described, which relates to a ceramic substrate.

[0011] [Overview of ceramic substrate structure] First, an overview of the ceramic substrate according to the first embodiment will be described. Fig. 1 is a cross-sectional view showing an overview of the ceramic substrate according to the first embodiment. As shown in Fig. 1, the ceramic substrate 1 has a first wiring layer 11, a first ceramic layer 12, a second wiring layer 13, a second ceramic layer 14, a third wiring layer 15, a third ceramic layer 16, an electrode 17, and a fourth ceramic layer 18. The first ceramic layer 12, the second ceramic layer 14, the third ceramic layer 16, and the fourth ceramic layer 18 constitute a ceramic insulating base material.

[0012] The first wiring layer 11 is formed on one surface (the surface on the Z2 side) of the second ceramic layer 14. The material of the first wiring layer 11 may be, for example, tungsten (W). The material of the first wiring layer 11 may also be molybdenum (Mo). The thickness of the first wiring layer 11 may be, for example, about 5 μm. The first wiring layer 11 is an example of a conductive layer.

[0013] Examples of materials that can be used for the second ceramic layer 14 include sodium oxide (Na2O), aluminum oxide (Al2O3), boron oxide (B2O3), and silicon dioxide (SiO2). The thickness of the second ceramic layer 14 can be, for example, about 10 μm.

[0014] The second ceramic layer has a first via hole 14x that exposes the upper surface (the surface on the Z1 side) of the first wiring layer 11. The first via hole 14x penetrates the second ceramic layer .

[0015] The second wiring layer 13 is formed on the other surface (the surface on the Z1 side) of the second ceramic layer 14. The second wiring layer 13 includes via fills filled in the first via holes 14x and a wiring pattern formed on the second ceramic layer 14. The second wiring layer 13 is electrically connected to the first wiring layer 11 exposed in the first via holes 14x. The thickness of the wiring pattern constituting the second wiring layer 13 can be, for example, about 5 μm.

[0016] The third ceramic layer 16 is formed on the second ceramic layer 14 so as to cover the second wiring layer 13. Examples of materials that can be used for the third ceramic layer 16 include sodium oxide (Na2O), aluminum oxide (Al2O3), boron oxide (B2O3), and silicon dioxide (SiO2). The thickness of the third ceramic layer 16 can be, for example, approximately 10 μm. Second via holes 16x are formed in the third ceramic layer 16, exposing the upper surface (surface on the Z1 side) of the second wiring layer 13. The second via holes 16x penetrate the third ceramic layer 16.

[0017] The third wiring layer 15 is formed on the third ceramic layer 16. The third wiring layer 15 includes via fills filled in the second via holes 16x and a wiring pattern formed on the third ceramic layer 16. The third wiring layer 15 is electrically connected to the second wiring layer 13 exposed in the second via holes 16x. The thickness of the wiring pattern constituting the third wiring layer 15 can be, for example, about 5 μm.

[0018] The fourth ceramic layer 18 is formed on the third ceramic layer 16 so as to cover the third wiring layer 15. Examples of materials that can be used for the fourth ceramic layer 18 include sodium oxide (Na2O), aluminum oxide (Al2O3), boron oxide (B2O3), and silicon dioxide (SiO2). The thickness of the fourth ceramic layer 18 can be, for example, about 10 μm. A third via hole 18x is formed in the fourth ceramic layer 18, exposing the upper surface (the surface on the Z1 side) of the third wiring layer 15. The third via hole 18x penetrates the fourth ceramic layer 18.

[0019] The electrode 17 includes a via fill filled in the third via hole 18x. The Z1-side surface 17a of the electrode 17 is substantially flush with the Z1-side surface 16a of the fourth ceramic layer 18. In other words, the surface 17a of the electrode 17 is exposed from the surface 16a of the fourth ceramic layer 18. The electrode 17 is electrically connected to the third wiring layer 15 exposed in the third via hole 18x. The thickness of the electrode 17 can be, for example, approximately 5 μm.

[0020] The first ceramic layer 12 is formed on one surface (the surface on the Z2 side) of the second ceramic layer 14 so as to cover the first wiring layer 11. An opening 12x is formed in the first ceramic layer 12, and a portion of the first wiring layer 11 is exposed in the opening 12x of the first ceramic layer 12. Examples of materials that can be used for the first ceramic layer 12 include sodium oxide (Na2O), aluminum oxide (Al2O3), boron oxide (B2O3), and silicon dioxide (SiO2). The thickness of the first ceramic layer 12 can be, for example, approximately 15 μm. The first ceramic layer 12 is an example of an insulating layer.

[0021] A metal component 120 is provided inside the opening 12x. The metal component 120 is joined to the first wiring layer 11 by a solder joint layer 30. The solder joint layer 30 preferably has a melting point of 250°C or higher and a low coefficient of thermal expansion. The composition of the solder joint layer 30 is preferably Au-Sn, Sn-Sb, Sn-Cu, Sn-Bi, or any of these with Ag, Ge, Sb, Ni, etc. added.

[0022] [Metal parts composition] Next, the configuration of the metal component 120 will be described. Fig. 2 is a top view showing the metal component in the first embodiment. Fig. 3 is a bottom view showing the metal component in the first embodiment. Fig. 4 is a front view showing the metal component in the first embodiment.

[0023] 2 to 4, the metal part 120 in the first embodiment has a cylindrical shape. The metal part 120 has a first main surface 121, a second main surface 122 opposite to the first main surface 121, and a side surface 123.

[0024] A plurality of first grooves 126 extending radially from the center to the outer edge are formed in the first main surface 121. A total of eight first grooves 126 are formed, for example, at intervals of 45° in the circumferential direction. For example, the depth of each first groove 126 is 50 μm to 100 μm, and the width is 100 μm to 300 μm.

[0025] The metal component 120 has a plurality of through holes 127 formed therein, penetrating from the first main surface 121 to the second main surface 122. In the first main surface 121, the first grooves 126 and the through holes 127 are offset from each other. A total of four through holes 127 are formed, for example, at intervals of 90° in the circumferential direction. For example, the diameter of the through holes 127 is 100 μm to 300 μm.

[0026] A plurality of second grooves 128 are formed in the side surface 123, connecting to the first main surface 121 and the second main surface 122. A total of eight second grooves 128 are formed, for example, at intervals of 45° in the circumferential direction. Each second groove 128 connects to a first groove 126 in the first main surface 121. For example, the depth of the second groove 128 is 50 μm to 100 μm, and the width is 100 μm to 300 μm.

[0027] The diameter of the metal part 120 is smaller than the diameter of the opening 12x, and a gap 143 exists between the metal part 120 and the inner wall surface of the opening 12x (see FIGS. 6 and 7).

[0028] [Configuration of the first wiring layer] Next, a description will be given of the configuration of the first wiring layer 11. Fig. 5 is a bottom view showing the first wiring layer.

[0029] As shown in FIG. 5, the first wiring layer 11 has a protrusion 130 that protrudes into the opening 12x. The protrusion 130 has a cylindrical shape. For example, the height of the protrusion 130 is 50 μm to 100 μm. The diameter of the protrusion 130 is smaller than the diameter of the opening 12x, and a gap 142 exists between the protrusion 130 and the inner wall surface of the opening 12x (see FIGS. 7 and 8). For example, the size of the gap 142 is 50 μm to 100 μm. The gap 142 is an example of a second gap. It is preferable to apply nickel plating, or gold plating on the nickel plating, to the protrusion 130.

[0030] A plurality of third grooves 136 extending radially from the center to the outer edge are formed on the Z2-side surface 131 of the protrusion 130. A total of eight third grooves 136 are formed, for example, at intervals of 45° in the circumferential direction. For example, the depth of the third grooves 136 is 50 μm to 100 μm, and the width is 100 μm to 300 μm.

[0031] [Joint structure between the first wiring layer and metal parts] Next, the bonding structure between the first wiring layer 11 and the metal component 120 will be described. Figs. 6 to 8 are cross-sectional views showing the bonding structure between the first wiring layer 11 and the metal component 120. Fig. 6 corresponds to a cross-sectional view taken along line VI-VI in Figs. 2, 3, and 5. Fig. 7 corresponds to a cross-sectional view taken along line VII-VII in Figs. 2, 3, and 5. Fig. 8 corresponds to a cross-sectional view taken along line VIII-VIII in Figs. 2, 3, and 5.

[0032] 6 to 8, the metal component 120 is inserted into the opening 12x so that the first main surface 121 faces the surface 131 of the protrusion 130. For example, the through hole 127 of the metal component 120 and the third groove 136 of the protrusion 130 may overlap each other in a plan view. A solder joint layer 30 is provided between the first main surface 121 and the surface 131.

[0033] 6 and 7, a gap 143 exists between the metal part 120 and the inner wall surface of the opening 12x. Furthermore, as shown in Fig. 8, in the portion where the second groove 128 is formed, a gap 141 larger than the gap 143 exists between the metal part 120 and the inner wall surface of the opening 12x. The gap 141 is an example of a first gap.

[0034] When joining the metal component 120 to the first wiring layer 11, a solder material that will become the solder joint layer 30 is placed between the first wiring layer 11 and the metal component 120, heated to melt the solder material, and then cooled to form the solder joint layer 30. The solder material contains flux, which volatilizes when melted. In this embodiment, the volatilized flux is discharged to the outside of the opening 12x, for example, through the third groove 136 and the through hole 127, and also through the first groove 126 or the third groove 136 and the second groove 128. Therefore, voids are less likely to exist in the solder joint layer 30. In other words, this embodiment can reduce voids in the solder joint layer.

[0035] Furthermore, the molten solder material not only remains between the first main surface 121 and the surface 131, but also flows into the gaps 141 and 142 and the through-holes 127. This makes it possible to obtain a large contact area between the solder joint layer 30 and the first wiring layer 11, and also between the solder joint layer 30 and the metal component 120. Therefore, an excellent anchor effect can be obtained.

[0036] Furthermore, the thickness (dimension in the Z1-Z2 direction) of the solder joint layer 30 is non-uniform within a plane parallel to the XY plane. For example, the thickness differs between the portion sandwiched between the first main surface 121 and the surface 131, the portion extending into the third groove 136, and the portion extending into the first groove 126. Generally, intermetallic compounds grow in the solder joint layer due to aging or other reasons when used at high temperatures of 200°C or higher, and fatigue failure of the solder joint layer may occur due to the growth of the intermetallic compounds. In contrast, in this embodiment, the non-uniform thickness of the solder joint layer 30 can suppress fatigue failure of the solder joint layer 30 due to the growth of the intermetallic compounds.

[0037] In this way, according to the first embodiment, it is possible to improve the bonding reliability.

[0038] For example, power may be supplied to the first wiring layer 11 via the metal part 120.

[0039] (Second embodiment) Next, a second embodiment will be described. The second embodiment differs from the first embodiment mainly in the configuration of the metal part. Fig. 9 is a top view showing the metal part in the second embodiment.

[0040] In the second embodiment, a metal component 220 is provided inside the opening 12x instead of the metal component 120. The metal component 220 is joined to the first wiring layer 11 by a solder joint layer 30.

[0041] In place of the through hole 127, the metal component 220 has a plurality of through holes 227 formed therein that penetrate from the first main surface 121 to the second main surface 122. In the first main surface 121, the first grooves 126 and the through holes 227 overlap each other. A total of four through holes 227 are formed, for example, at intervals of 90° in the circumferential direction. For example, the diameter of the through holes 227 is 100 μm to 300 μm.

[0042] The other configuration of the metal part 220 is similar to that of the metal part 120 .

[0043] Next, a description will be given of the joint structure between the first wiring layer 11 and the metal component 220. Fig. 10 is a cross-sectional view showing the joint structure between the first wiring layer 11 and the metal component 220. Fig. 10 corresponds to a cross-sectional view taken along line XX in Fig. 9.

[0044] 10, the metal component 220 is inserted into the opening 12x so that the first main surface 121 faces the surface 131 of the protrusion 130. For example, in a plan view, the through hole 227 of the metal component 220 and the third groove 136 of the protrusion 130 may be misaligned in the circumferential direction.

[0045] The other configurations are the same as those in the first embodiment.

[0046] When joining the metal component 220 to the first wiring layer 11, a solder material that will become the solder joint layer 30 is placed between the first wiring layer 11 and the metal component 220, heated to melt the solder material, and then cooled to form the solder joint layer 30. The solder material contains flux, and the flux volatilizes when melted. In this embodiment, the volatilized flux is discharged to the outside of the opening 12x through, for example, the first groove 126 and the through hole 227, and is also discharged to the outside of the opening 12x through the first groove 126 or the third groove 136 and the second groove 128.

[0047] Therefore, similar to the first embodiment, the second embodiment can also improve the bonding reliability.

[0048] In the present disclosure, the planar shape of the ceramic substrate is not particularly limited. For example, the planar shape of the ceramic substrate may be rectangular or circular.

[0049] The material of the metal part is not particularly limited, and for example, a material in which a base material of a tungsten copper alloy is plated with nickel can be used.

[0050] Furthermore, the shape of the metal part is not limited to a cylindrical shape, but may be a polygonal pillar shape or the like.

[0051] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0052] 1. Ceramic substrate 11 1st wiring layer 12x opening 30 Solder joint layer 120, 220 Metal parts 121 First main surface 122 Second main surface 123 Side 126 First groove 127, 227 through holes 128 Second groove 130 Convex 131 sides 136 Third groove 141, 142 gap

Claims

1. A columnar metal component having a first main surface and a second main surface opposite to the first main surface, a plurality of first grooves are formed in the first main surface, the first grooves extending radially from a center to an outer edge of the first main surface; A metal part characterized in that a plurality of through holes penetrating from the first main surface to the second main surface are formed at positions away from the center of the first main surface in a plan view.

2. The metal part according to claim 1 , further comprising a side surface on which a second groove is formed, the second groove connecting to the first main surface and the second main surface.

3. The metal part according to claim 2 , wherein the first groove and the second groove are continuous with each other.

4. 4. The metal part according to claim 1, wherein the first groove and the through hole are offset from each other on the first main surface.

5. 4. The metal part according to claim 1, wherein the first groove and the through hole are positioned to overlap each other on the first main surface.

6. a ceramic insulating substrate; a conductive layer provided on one surface of the insulating substrate; an insulating layer provided on one surface of the insulating base material and covering the conductive layer; and an opening is formed in the insulating layer to expose a portion of the conductive layer; The metal component according to any one of claims 1 to 5 is provided inside the opening, A ceramic substrate, characterized in that the first main surface of the metal component is joined to the conductive layer via a solder joint layer.

7. A ceramic insulating substrate; a conductive layer provided on one surface of the insulating substrate; an insulating layer provided on one surface of the insulating base material and covering the conductive layer; and an opening is formed in the insulating layer to expose a portion of the conductive layer; a columnar metal component having a first main surface and a second main surface opposite to the first main surface is provided inside the opening, a first groove is formed in the first main surface; a through hole is formed penetrating from the first main surface to the second main surface, A ceramic substrate, characterized in that the first main surface of the metal component is joined to the conductive layer via a solder joint layer.

8. A ceramic substrate as described in Claim 7, characterized in that it has a side surface on which a second groove connecting to the first main surface and the second main surface is formed.

9. A ceramic substrate as described in claim 8, characterized in that the first groove and the second groove are connected to each other.

10. A ceramic substrate as described in any one of claims 7 to 9, characterized in that the positions of the first groove and the through hole are offset from each other on the first main surface.

11. A ceramic substrate as described in any one of claims 7 to 9, characterized in that the positions of the first groove and the through hole overlap each other on the first main surface.

12. 12. The ceramic substrate according to claim 6, wherein a first gap exists between the metal component and an inner wall surface of the opening.

13. the conductive layer has a protrusion protruding into the opening, 13. The ceramic substrate according to claim 6, wherein a second gap exists between the protrusion and an inner wall surface of the opening.

14. 14. The ceramic substrate according to claim 13, wherein a third groove is formed on a surface of the protrusion that faces the metal component.

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