Electronic components

Abstract

We provide electronic components with enhanced resistance to thermal shock. [Solution] The electronic component 10 has a functional element 12 and an electrode 20, and the functional element 12 is mounted on a substrate 30. The electrode 20 includes a base conductive layer 22 and a thermal deformation following layer 24. The thermal deformation following layer 24 is composed of a conductive layer 26 provided on the surface of the base conductive layer 22 and is capable of following the thermal deformation of the portion surrounding the thermal deformation following layer 24, and the thermal deformation following layer 24 is composed of an aluminum layer. The aluminum layer can be a plating layer.

Description

Technical Field

[0001] The present invention relates to an electronic component having functional elements.

Background Art

[0002] Various electrical functional elements are mounted on a circuit board. Examples of the functional elements include a chip resistor (see Patent Document 1) and a ceramic capacitor (see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] A power module substrate on which a power semiconductor such as SiC or GaN is mounted requires high heat resistance, and in the heat resistance evaluation test, it is necessary to perform the test with the low temperature side at -50°C and the high temperature side at 200°C or higher for more than a thousand cycles. In the electronic components constituting the power module substrate, it is an important issue to have a configuration that can withstand thermal shock (heat shock).

[0005] An object of the present invention is to provide an electronic component with enhanced durability against thermal shock.

Means for Solving the Problems

[0006] The electronic component of the present invention is an electronic component having a functional element and an electrode electrically connected to the functional element, wherein the electrode includes a base conductive layer and a thermal deformation following layer, The thermal deformation-following layer is composed of a conductive layer provided on the surface of the underlying conductive layer, and is capable of following the thermal deformation of the portion surrounding the thermal deformation-following layer. The thermal deformation-following layer may be composed of an aluminum layer.

[0007] In the present invention, the functional element is mounted on a substrate, and the electrode electrically connects the functional element to a connecting electrode provided on the substrate.

[0008] In the present invention, the thickness of the thermal deformation-following layer can be 5.0 to 40 μm.

[0009] In the present invention, the aluminum layer may be a plating layer.

[0010] In this specification, "A to B" means A or greater and B or less, and the expression "Z is A to B" means that Z is within the range of A to B. [Effects of the Invention]

[0011] According to the present invention, even if thermal deformation occurs in electronic components or substrates, the thermal deformation-following layer can absorb that deformation, thereby suppressing the occurrence of cracks and other damage. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an electronic component according to an embodiment. [Figure 2] This figure schematically shows a cross-section along the line A1-A1 in Figure 1. [Figure 3] This figure schematically shows an example of an electronic component according to the embodiment mounted on a substrate. [Figure 4] This diagram schematically shows an electronic component using a multilayer ceramic capacitor as an example of a functional element. [Figure 5] This diagram schematically shows an electronic component that uses a resistor as an example of a functional element. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described in detail below.

[0014] The electronic component 10 according to this embodiment includes a functional element 12 and an electrode 20. The functional element 12 is mounted on a substrate 30. The electrode 20 includes a base conductive layer 22 and a thermal deformation-following layer 24. The thermal deformation-following layer 24 is composed of a conductive plating layer provided on the surface of the base conductive layer 22 and is capable of following the thermal deformation of the portion surrounding the thermal deformation-following layer 24. The electronic component 10 may be a configuration in which the functional element 12 and the electrode 20 are integrated and not mounted on the substrate 30, or it may be a mounting structure in which the functional element 12 and the electrode 20 are integrated and mounted on the substrate 30, or it may be a concept that includes both. The electronic component 10 may include the substrate 30, or it may not include the substrate 30.

[0015] Examples of functional elements 12 include chip components such as multilayer ceramic capacitors, chip resistors, capacitors, and diodes. An example of an electrode 20 is an external electrode connected to the internal electrode layer 14 in the case of a multilayer ceramic capacitor (see Figure 4). In the case of a chip resistor (see Figure 5), if the chip resistor is realized by providing two conductors (functioning as electrodes) on the surface of an insulating substrate that constitutes part of the chip resistor, and providing a resistor 16 between the two conductors, then an example of an electrode 20 is the two conductors themselves or a wiring structure electrically connected to these conductors. The electrode 20 may be electrically connected to the conductive part of the functional element 12 and also electrically connected to a conductive part provided on the substrate 30. The electrode 20 may also constitute part of the conductive part of the functional element 12.

[0016] The substrate 30 can be, for example, a substrate on which semiconductor chips are mounted, and is particularly effective for a substrate on which power semiconductor chips are mounted. The substrate 30 can be provided with connection electrodes (for example, lands) 35 for electrically connecting to the electrodes 20. Through the connection electrodes 35, the wiring provided on the substrate 30 and the electronic component 10 can be electrically connected.

[0017] The underlying conductive layer 22 may be a metal layer or a conductive resin layer. The underlying conductive layer 22 can be provided by electroless plating or by applying a conductive material. Examples of the material of the metal layer include silver, gold, nickel, and the like. A conductive paste (for example, a polyimide-based conductive paste) containing conductive metal powder, glass, and an organic vehicle may be applied and baked to provide the underlying conductive layer 22 made of a conductive resin layer. The underlying metal layer may be formed, for example, by sputtering a metal film (for example, Ni-Cr).

[0018] The thermal deformation following layer 24 can be composed of an aluminum layer. The aluminum layer has good malleability and has a so-called soft property, so it is suitable for the thermal deformation following layer 24. The thermal deformation following layer 24 can be composed of an aluminum plating layer. The thickness of the thermal deformation following layer 24 can be, for example, within the range of 5.0 to 40 μm, preferably within the range of 10 to 30 μm. The conductive plating layer of the thermal deformation following layer 24 can be provided by barrel plating. Known methods such as aluminum ion plating can be applied as the method for plating aluminum. The aluminum layer may contain impurities such as silicon.

[0019] An electrode plating layer 26 may be provided on the thermal deformation following layer 24. When a natural oxide film has formed on the surface of the thermal deformation following layer 24 before providing the electrode plating layer 26, it is preferably removed. The electrode plating layer 26 can include known plating layers used for the terminals of the electronic component 10. The electrode plating layer 26 can be composed of, for example, a nickel plating layer and a tin plating layer provided on the nickel plating layer.

[0020] The electronic component 10 can be mounted on, for example, a substrate 30 with solder 32.

[0021] The electronic component 10 near the periphery of the power semiconductor has a rapid rise and fall in temperature and a severe temperature cycle, so cracks may occur in the electronic component 10. Due to the presence of the deformation following layer, it has resistance to severe temperature cycles and can suppress the occurrence of cracks. Also, the thermal stress during heat shock can be absorbed by the thermally deformable following layer 24.

[0022] Since the coefficient of thermal expansion between the substrate 30 and the solder 32 is different, in the electrode 20, due to the presence of the thermally deformable following layer 24, the expansion difference between the substrate 30 and the solder 32 can be absorbed.

[0023] This embodiment can be variously modified within the scope of the present invention.

Explanation of Reference Numerals

[0024] 10 Electronic component 12 Functional element 12a Resistor 20 Electrode 22 Underlying conductive layer 24 Thermally deformable following layer 26 Electrode plating layer 30 Substrate 32 Solder 34 Connection electrode

Claims

1. An electronic component having a functional element and an electrode electrically connected to the functional element, The electrode includes a base conductive layer and a thermal deformation-following layer. The thermal deformation-following layer is composed of a conductive layer provided on the surface of the underlying conductive layer, and is capable of following the thermal deformation of the portion surrounding the thermal deformation-following layer. The aforementioned thermal deformation-following layer is an electronic component composed of an aluminum layer.

2. In claim 1, The aforementioned functional element is mounted on a substrate, The electrode is an electronic component that electrically connects the functional element and the connecting electrode provided on the substrate.

3. In claim 1, The thickness of the thermal deformation-following layer is 5.0 to 40 μm in this electronic component.

4. In claim 1, The aforementioned aluminum layer is a plated layer in an electronic component.

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