Component mounting substrate, method for manufacturing component mounting substrate, electronic module, and method for manufacturing electronic module

Abstract

The invention provides an electronic module capable of preventing creeping discharge and improving productivity. An electronic module (30) is provided with: a circuit board (12) in which a metal layer (16) constituting a wiring pattern (18) and a metal base (13) are laminated with an insulating layer (14) therebetween; an electronic component (20) bonded to the wiring pattern (18); and a coating film (24) formed on the surface and side surfaces of the electronic component (20) and the circuit board (12) by ceramic coating or glass coating.

Description

Technical Field

[0001] The present disclosure relates to a component mounting substrate, a method for manufacturing the component mounting substrate, an electronic module, and a method for manufacturing the electronic module. Background Art

[0002] Japanese Patent Gazette No. 2021-34534 discloses a circuit substrate formed by stacking a circuit portion and a base substrate with an insulating layer interposed therebetween. On a metal plate constituting the circuit portion, a wiring pattern is formed by etching, and a resin portion made of a resin different from the insulating layer is provided in the gaps between the wiring patterns and along the peripheral edges of the wiring patterns. Electronic components such as semiconductor elements are mounted on such a circuit substrate, and the electronic components and the circuit substrate are sealed with a sealing resin. Thus, an electronic module is manufactured. Summary of the invention

[0003] Problems to be solved by the invention

[0004] In recent years, with the diversification of the use environment of electronic equipment, it is required to increase the current capacity of the circuit substrate of the electronic module. The current capacity of the circuit substrate can be increased by thickening the metal plate constituting the wiring pattern. However, when the metal plate constituting the wiring pattern is thickened, sometimes the sealing resin peels off and bubbles occur in the gaps between the wiring patterns and the peripheral edges of the wiring patterns. When a voltage is applied to the circuit substrate in this state, surface discharge will occur in the gaps between the wiring patterns and the peripheral edges of the wiring patterns. Such surface discharge becomes the cause of insulation breakdown.

[0005] In this regard, in the above-mentioned prior art, since the resin portion is provided in the gaps between the wiring patterns and the peripheral edge of the wiring patterns, the peeling of the sealing resin and the generation of bubbles as described above can be prevented. However, since the resin adheres to the surface of the wiring pattern when the above-mentioned resin portion is provided, a resin grinding process is required to remove the resin on the surface of the wiring pattern. In the resin grinding process, problems such as clogging of the polisher used in grinding may occur, so that productivity will deteriorate.

[0006] The present disclosure has been made in consideration of the above-mentioned facts, and an object of the present disclosure is to provide a component mounting substrate, a method for manufacturing a component mounting substrate, an electronic module, and a method for manufacturing an electronic module that can prevent the occurrence of creeping discharge and improve productivity.

[0007] Solutions for solving problems

[0008] The component mounting substrate of the first scheme comprises: a circuit substrate, which is formed by stacking a conductor layer constituting a wiring pattern and a base substrate via an insulating layer; an electronic component joined to the wiring pattern; and a coating film formed on the surface and side surfaces of the electronic component and the circuit substrate by ceramic coating or glass coating.

[0009] According to the component mounting substrate of the first scheme, the circuit substrate is formed by stacking a conductor layer and a base substrate constituting a wiring pattern through an insulating layer, and an electronic component is bonded to the wiring pattern. A coating film is formed on the surface and side of the electronic component and the circuit substrate by ceramic coating or glass coating. The coating film is sandwiched between the sealing resin that seals the surface and side of the electronic component and the circuit substrate and the electronic component and the circuit substrate. Therefore, even if the sealing resin peels off or bubbles occur in the gap between the wiring patterns or along the peripheral edge of the wiring patterns, the generation of surface discharge can be prevented. In addition, since there is no need for a process of providing a resin portion in the gap between the wiring patterns or the like, and a resin grinding process of removing the resin attached to the surface of the wiring pattern, productivity is improved.

[0010] The manufacturing method of the component mounting substrate of the second aspect comprises: a main body preparation step of preparing a mounting substrate main body including a circuit substrate and an electronic component, wherein the circuit substrate is formed by laminating a conductor layer constituting a wiring pattern and a base substrate via an insulating layer, and the electronic component is bonded to the wiring pattern; and

[0011] In the coating step, ceramic coating or glass coating is applied to the surfaces and side surfaces of the electronic components and the circuit board.

[0012] According to the manufacturing method of the component mounting substrate of the second scheme, in the main body preparation process, a mounting substrate body having a circuit substrate and an electronic component is prepared, wherein the circuit substrate is formed by stacking a conductor layer and a base substrate constituting a wiring pattern through an insulating layer, and the electronic component is bonded to the wiring pattern. In the coating process, ceramic coating or glass coating is applied to the surface and side of the electronic component and the circuit substrate. The coating film formed by the coating process is sandwiched between the sealing resin that seals the surface and side of the electronic component and the circuit substrate and the electronic component and the circuit substrate. Therefore, even if the sealing resin peels off or bubbles occur in the gap between the wiring patterns or along the peripheral edge of the wiring patterns, the generation of surface discharge can be prevented. Moreover, since there is no need for a process of setting a resin portion in the gap between the wiring patterns or the like, and a resin grinding process of removing the resin attached to the surface of the wiring pattern, productivity is improved.

[0013] The electronic module of the third scheme comprises: a circuit substrate, which is formed by stacking a conductor layer constituting a wiring pattern and a base substrate via an insulating layer; an electronic component, which is bonded to the wiring pattern; a sealing resin, which seals the surface and side of the electronic component and the circuit substrate; and a coating film, which is formed on the surface and side of the electronic component and the circuit substrate by ceramic coating or glass coating, and is sandwiched between the circuit substrate, the electronic component and the sealing resin.

[0014] According to the electronic module of the third scheme, the circuit substrate is formed by stacking a conductor layer and a base substrate constituting a wiring pattern through an insulating layer, and an electronic component is joined to the wiring pattern. The surface and side of the electronic component and the circuit substrate are sealed with a sealing resin. A coating film formed on the surface and side of the electronic component and the circuit substrate by ceramic coating or glass coating is sandwiched between the circuit substrate and the electronic component and the sealing resin. Therefore, even if the sealing resin peels off or bubbles occur in the gaps between the wiring patterns or along the peripheral edges of the wiring patterns, the generation of surface discharge can be prevented. In addition, since there is no need for a process of providing a resin portion in the gaps between the wiring patterns or the like, and a resin grinding process of removing the resin attached to the surface of the wiring pattern, productivity is improved.

[0015] The manufacturing method of the electronic module of the fourth scheme comprises: a substrate preparation step of preparing a component mounting substrate having a circuit substrate and electronic components, wherein the circuit substrate is formed by stacking a conductor layer constituting a wiring pattern and a base substrate via an insulating layer, the electronic components are joined to the wiring pattern, and ceramic coating or glass coating is applied to the surface and side of the electronic components and the circuit substrate; and a sealing step of sealing the surface and side of the electronic components and the circuit substrate with a sealing resin.

[0016] According to the fourth scheme, in the substrate preparation process, a component mounting substrate having a circuit substrate and electronic components is prepared, wherein the circuit substrate is formed by stacking a conductor layer constituting a wiring pattern and a base substrate via an insulating layer, the electronic components are bonded to the wiring pattern, and ceramic coating or glass coating is applied to the surface and side of the electronic components and the circuit substrate. In the sealing process, the surface and side of the electronic components and the circuit substrate are sealed by a sealing resin. The above-mentioned coating film is sandwiched between the sealing resin and the electronic components and the circuit substrate. Therefore, even if the sealing resin peels off or bubbles occur in the gaps between the wiring patterns or along the peripheral edges of the wiring patterns, the generation of surface discharge can be prevented. Moreover, since there is no need for a process of providing a resin portion in the gaps between the wiring patterns or the like, and a resin grinding process of removing the resin attached to the surface of the wiring patterns, productivity is improved.

[0017] Effects of the Invention

[0018] As described above, in the component mounting substrate, the method for manufacturing the component mounting substrate, the electronic module, and the method for manufacturing the electronic module of the present disclosure, the occurrence of creeping discharge can be prevented and productivity can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view showing a mounting substrate main body included in the component mounting substrate according to the embodiment.

[0020] Figure 2It is a cross-sectional view showing a component mounting substrate according to the embodiment.

[0021] Figure 3 is a cross-sectional view showing an electronic module according to an embodiment.

[0022] Figure 4 is a cross-sectional view showing an electronic module according to a first comparative example.

[0023] Figure 5 is a cross-sectional view showing an electronic module according to a second comparative example. DETAILED DESCRIPTION

[0024] Below, refer to Figure 1 to Figure 5 A component mounting substrate 10 and an electronic module 30 according to an embodiment of the present disclosure will be described. Figure 3 As shown, the electronic module 30 of this embodiment is composed of a component mounting substrate 10 and a sealing resin 26. Figure 2 As shown, the component mounting substrate 10 is composed of a circuit substrate 12 , an electronic component 20 as a heat generating body, and a coating film 24 .

[0025] like Figure 1 to Figure 3 As shown, the circuit board 12 includes: a metal base 13; an insulating layer 14 stacked on the metal base 13; and a metal layer 16 stacked on the side of the insulating layer 14 opposite to the metal base 13, forming a wiring pattern (circuit pattern) 18. The metal base 13 is equivalent to the "base substrate" in the present disclosure, and the metal layer 16 is equivalent to the "conductor layer" in the present disclosure.

[0026] The metal base 13 is a substrate made of a metal material. As the material of the metal plate constituting the metal base 13, for example, copper, copper alloy, aluminum, aluminum alloy, etc. having high thermal conductivity can be used. The thickness of the metal base 13 is set in the range of 1.0 mm to 3.0 mm, for example. It should be noted that a heat dissipation unit (not shown) such as a heat sink or a radiator may be mounted on the surface of the metal base 13 on the side opposite to the insulating layer 14.

[0027] The insulating layer 14 is formed, for example, by mixing a filler having insulating and thermal conductivity into a synthetic resin having electrical insulating properties. As the above-mentioned synthetic resin, for example, a synthetic resin having high electrical insulating properties and thermal conductivity, such as epoxy resin, which is a thermosetting synthetic resin having an epoxy group, can be used. As the above-mentioned filler, for example, a filler that is chemically stable and has high thermal conductivity and electrical insulating properties, such as silica, alumina, aluminum nitride, and boron nitride can be used. The thickness of the insulating layer 14 is set, for example, in the range of 0.06 mm to 0.2 mm. It should be noted that the insulating layer 14 can also be formed by mixing glass fibers into the synthetic resin having electrical insulating properties instead of the filler having thermal conductivity.

[0028] The metal layer 16 is, for example, made of a conductive metal material. As the metal material constituting the metal layer 16, for example, a rolled copper plate, an aluminum plate, etc. can be used. The thickness of the metal layer 16 is, for example, set in the range of 0.3 mm to 1.5 mm. The metal layer 16 is formed by etching the metal layer on the side opposite to the metal substrate 13 stacked in the insulating layer 14, and constitutes a predetermined wiring pattern 18. Metal plating is applied to the surface of the wiring pattern 18 (not shown). The thickness of the metal plating is, for example, set in the range of 0.1 μm to 0.4 μm. It should be noted that the metal layer 16 can also be formed by punching the lead frame material by die stamping. However, in the case of die stamping, burrs are easily generated, so before the metal layer 16 is stacked on the insulating layer 14, a process for removing the burrs is required.

[0029] The electronic component 20 is bonded to the surface of the wiring pattern 18 using solder 22, which is an example of a conductive bonding material. Thus, the mounting substrate main body 11 is formed. Examples of the electronic component 20 include semiconductor chips, transistors, diodes, light-emitting diodes, thyristors, capacitors, resistors, resistor arrays, coils, switches, and the like.

[0030] The coating film 24 is a thin film formed on the surface and side of the electronic component 20 and the circuit board 12 by ceramic coating. As a method for forming the coating film 24, for example, a sol-gel method can be cited. The main components of the ceramic coating are, for example, ceramic powders such as silicon dioxide, aluminum oxide, zirconium oxide, and silicon carbide, an inorganic binder, and water as a solvent. The film thickness of the coating film 24 is set in the range of 1 μm to 10 μm, for example. By forming the coating film 24, Figure 2 The component mounting substrate 10 is shown.

[0031] Since the ceramic coating has high heat resistance, it will not deteriorate in the operating temperature range of general power modules (below 200°C). In the sol-gel method, since the object can be processed by immersing and removing the object into a low-viscosity sol solution, the construction can be performed after the electronic component 20 is mounted on the mounting substrate body 11. It should be noted that glass coating can also be used instead of ceramic coating.

[0032] In the electronic module 30 including the above-mentioned component mounting substrate 10, as Figure 3 As shown, the electronic component 20 and the surface and side surfaces of the circuit board 12 are sealed with a sealing resin 26. The sealing resin 26 is formed by, for example, transfer molding.

[0033] Next, a method for manufacturing the component mounting substrate 10 and the electronic module 30 having the above-described structure is described. When manufacturing the component mounting substrate 10, first, a laminated body including the metal base 13, the insulating layer 14, and the metal layer 16 is prepared, and the metal layer 16 is etched to form the wiring pattern 18.

[0034] As a method for manufacturing the above-mentioned laminate, a well-known method can be used. For example, a liquid material (varnish material) as a material of the insulating layer 14 can be applied to at least one of the metal substrate 13 and the metal layer 16 by roller coating, rod coating or screen printing. Afterwards, the liquid material on the metal substrate 13 or the metal layer 16 is dried by natural drying or forced drying. Thus, the insulating layer 14 is obtained. The insulating layer 14 at this time may also be in an uncured state (the so-called B stage state). Next, a metal layer 16 is formed on the surface of the insulating layer 14. Specifically, a metal layer 16 (for example, a rolled copper plate) is stacked on the surface of the insulating layer 14 to form a wiring pattern 18 by hot pressing or the like. Thus, a laminate in which the metal layer 16 constituting the wiring pattern 18 and the metal substrate 13 are stacked with the insulating layer 14 therebetween is obtained.

[0035] In the next etching step, the metal layer 16 of the laminated body obtained as described above is etched to form a predetermined wiring pattern 18. In the next automatic optical inspection step, the laminated body after the etching step is inspected for defects. In the next plating step, the surface of the wiring pattern 18 after the formal curing step is not polished but metal plating is performed on the surface (not shown).

[0036] In the next component mounting step, the electronic component 20 is bonded to the surface of the wiring pattern 18 using solder 22. Thus, the mounting substrate body 11 is completed. In the next coating step, ceramic coating is applied to the surface and side of the electronic component 20 and the circuit substrate 12 by, for example, a sol-gel method. Thus, the component mounting substrate 10 is completed. In the next sealing step, the sealing resin 26 is molded by, for example, transfer molding. Thus, the electronic module 30 is completed.

[0037] In the electronic module 30 of the above structure, the circuit substrate 12 is formed by stacking the metal layer 16 and the metal base 13 constituting the wiring pattern 18 via the insulating layer 14, and the electronic component 20 is bonded to the wiring pattern 18. The surfaces and sides of the electronic component 20 and the circuit substrate 12 are sealed by the sealing resin 26. Between the circuit substrate 12 and the electronic component 20 and the sealing resin 26, there is a coating film 24 formed on the surfaces and sides of the electronic component 20 and the circuit substrate 12 by ceramic coating. Therefore, as Figure 3 As shown, even if peeling of the sealing resin or bubbles occur in the gaps between the wiring patterns 18 or in the peripheral edges of the wiring patterns 18, the occurrence of creeping discharge can be prevented.

[0038] use Figure 4 and Figure 5 The above effects are supplemented. Figure 4 As in the first comparative example shown in FIG. 1 , when the sealing resin 26 is not peeled off or bubbles are not generated in the gaps between the wiring patterns 18 or the peripheral edges of the wiring patterns 18, no surface discharge occurs. However, when the metal layer 16 constituting the wiring patterns 18 is thickened, as shown in FIG. Figure 5 As shown in the second comparative example, the sealing resin 26 may peel off or bubbles may occur in the gaps between the wiring patterns 18 and the peripheral edges of the wiring patterns 18. When a voltage is applied to the electronic module 30 in this state, creeping discharge may occur in the gaps between the wiring patterns 18 and the peripheral edges of the wiring patterns 18. Such creeping discharge may cause the insulation layer 14 to be destroyed, but this can be avoided in the present embodiment.

[0039] Furthermore, in the present embodiment, productivity is improved because there is no need for a process of providing a resin portion in the gaps between the wiring patterns 18 or a resin grinding process of removing the resin attached to the surface of the wiring pattern 18. In particular, in the resin grinding process, productivity is deteriorated because a ceramic polisher that grinds the surface of the wiring pattern may become clogged, but this can be avoided in the present embodiment.

[0040] Although the present disclosure has been described above by showing the embodiment, the present disclosure can be implemented in various ways without departing from the gist of the present disclosure. In addition, the scope of rights of the present disclosure is of course not limited to the above-mentioned embodiment.

[0041] In addition, the entire disclosure of Japanese Patent Application No. 2022-175152 filed on October 31, 2022 is also incorporated into this specification by reference. All documents, patent applications, and technical standards described in this specification are incorporated into this specification by reference to the same extent as if each document, patent application, and technical standard was specifically and individually described as being incorporated into this specification by reference.

Claims

1. A component mounting substrate, comprising: The circuit board is formed by laminating a conductor layer constituting a wiring pattern and a base substrate with an insulating layer interposed therebetween; an electronic component joined to the wiring pattern; and The coating film is formed on the surface and side surfaces of the electronic component and the circuit board by ceramic coating or glass coating.

2. A method for manufacturing a component mounting substrate, comprising: The main body preparation step is to prepare a mounting substrate main body having a circuit board and electronic components. in, The circuit substrate is formed by laminating a conductor layer constituting a wiring pattern and a base substrate via an insulating layer, and the electronic component is bonded to the wiring pattern; and In the coating step, ceramic coating or glass coating is applied to the surfaces and side surfaces of the electronic components and the circuit board.

3. An electronic module comprising: The circuit board is formed by laminating a conductor layer constituting a wiring pattern and a base substrate with an insulating layer interposed therebetween; an electronic component joined to the wiring pattern; a sealing resin that seals the electronic component and the surface and side surfaces of the circuit substrate; and The coating film is formed on the surface and side surfaces of the electronic component and the circuit substrate by ceramic coating or glass coating, and is sandwiched between the circuit substrate, the electronic component, and the sealing resin.

4. A method for manufacturing an electronic module, comprising: The substrate preparation step is to prepare a component mounting substrate having a circuit substrate and electronic components. in, The circuit substrate is formed by laminating a conductor layer constituting a wiring pattern and a base substrate via an insulating layer, the electronic component is bonded to the wiring pattern, and ceramic coating or glass coating is applied to the surface and side of the electronic component and the circuit substrate; and The sealing step is to seal the electronic component and the surface and side surfaces of the circuit board with a sealing resin.

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