Insulated wiring board and electronic device thereof

Abstract

This application discloses an insulating circuit board and its electronic device, including a substrate, a metal layer, and a pre-formed solder layer. The metal layer is disposed between the substrate and the pre-formed solder layer. Along a first direction, the metal layer sequentially comprises a titanium layer, a copper layer, a nickel layer, a gold layer, and a platinum layer from the inside out. The length of the platinum layer along a second direction is greater than the length of the pre-formed solder layer along the second direction, and the length of the platinum layer along a third direction is not less than the length of the pre-formed solder layer along the third direction. This application, by providing a platinum layer with a relatively large width, and because the width of the platinum layer is greater than the width of the pre-formed solder layer, enhances the barrier effect, which helps to reduce the migration of gold elements into the pre-formed solder layer. It also further reduces the risk of melting point changes and the risk of intermetallic compounds, further increasing the mechanical properties and operational stability of the insulating circuit board.

Description

Technical Field

[0001] This application relates to the field of insulated circuit board technology, and more particularly to an insulated circuit board and its electronic equipment. Background Technology

[0002] Insulated circuit boards (ICs), also known as IC substrates, are core components of modern electronic devices, primarily providing mechanical support for the electrical connections between electronic components. Currently, ICs are typically manufactured using an etched copper-clad laminate method, where copper foil is deposited on the surface to form conductors or wiring. These conductors connect electronic components and undertake signal transmission, power supply, and heat dissipation tasks. The application of ICs effectively reduces the space occupied by conductors, facilitating optimized conductor layout and thus improving the integration and performance of electronic devices. Furthermore, ICs are used in numerous electronic product fields, including home appliances, computers, and communication equipment, forming the foundation of electronic systems.

[0003] With advancements in technology and ever-increasing demands on the performance of electronic devices, coupled with the rapid development of microelectronics integration technology, the requirements for the quality and performance of insulated circuit boards (PCBs) are becoming increasingly stringent. Therefore, insulated circuit boards, with their excellent thermal conductivity and low dielectric loss, are gradually becoming the focus of the market. These characteristics give insulated circuit boards unique advantages in applications with high thermal management and signal integrity requirements, such as in 5G communication equipment, laser pumping, and AI applications. Insulated circuit boards can significantly enhance signal processing and transmission rates, effectively improving data transmission performance and efficiency.

[0004] However, since insulating circuit boards often contain gold metal layers and gold-tin pre-formed solder layers, nickel or gold elements often migrate during the processing, further affecting the stability of chip packaging. Summary of the Invention

[0005] One objective of this application is to provide an insulating circuit board and its electronic device, which helps to reduce the migration of nickel or gold elements to the pre-formed solder layer, further reduces the risk of chip packaging failure caused by interlayer materials of the insulating circuit board, increases the stability of the pre-formed solder layer, and improves the quality of the IC carrier board.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: an insulating circuit board, comprising a substrate, a metal layer, and a pre-formed solder layer, wherein the metal layer is disposed between the substrate and the pre-formed solder layer, and the metal layer is provided with a titanium layer, a copper layer, a nickel layer, a gold layer, and a platinum layer sequentially from the inside to the outside along a first direction; the length of the platinum layer along a second direction is greater than the length of the pre-formed solder layer along the second direction, and the length of the platinum layer along a third direction is not less than the length of the pre-formed solder layer along the third direction.

[0007] In some embodiments, the projection of the preformed solder layer along the first direction falls inside the projection of the platinum layer along the first direction.

[0008] In some embodiments, the length of the platinum layer along a third direction is greater than the length of the preformed solder layer along a third direction.

[0009] In some embodiments, the thickness of the platinum layer is 0.1 μm to 3 μm.

[0010] In some embodiments, the thickness of the titanium layer is 0.05 μm to 0.2 μm, the thickness of the copper layer is 20 μm to 100 μm, the thickness of the nickel layer is 1 μm to 3 μm, and the thickness of the gold layer is 0.3 μm to 3 μm.

[0011] In some embodiments, the pre-formed solder layer is a gold-tin alloy, wherein the mass fraction of gold in the pre-formed solder layer is 70 wt.% to 80 wt.%.

[0012] In some embodiments, the thickness of the pre-formed solder layer is 2 μm to 6 μm.

[0013] In some embodiments, the substrate is aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, zirconium oxide, polyimide, or polytetrafluoroethylene.

[0014] In some embodiments, the platinum layer is electroplated with the pre-formed solder layer on the outer surface of the platinum layer on the side away from the substrate, and the distance between the side edge of the pre-formed solder layer along the second direction and the projection of the side edge of the platinum layer along the second direction in the first direction is 10 μm to 100 μm.

[0015] To achieve the above objectives, the technical solution adopted in this application is: an electronic device, including any of the insulating circuit boards described above.

[0016] Compared with the prior art, the beneficial effects of this application are as follows:

[0017] (1) By providing a platinum layer with a larger width, and because the width of the platinum layer is greater than the width of the pre-solder layer, the barrier effect is enhanced, which helps to reduce the migration of gold elements to the pre-solder layer and contaminate the pre-solder layer, affecting the pre-plating solder effect of the pre-solder layer, and further reducing the risk of melting point changes in the interlayer materials of the insulating circuit board.

[0018] (2) By providing a platinum layer, the coverage area of ​​the insulating circuit board is increased, thereby reducing the area of ​​the insulating circuit board surface exposed to the external environment, which is conducive to improving the stability of the insulating circuit board. Attached Figure Description

[0019] Fig. 1This is a front view schematic diagram of the layered structure of an insulating circuit board according to some embodiments of this application.

[0020] Fig. 2 This is a three-dimensional structural schematic diagram of an insulating circuit board according to some embodiments of this application.

[0021] Fig. 3 This is a top view of the three-dimensional structure of an insulating circuit board according to some embodiments of this application.

[0022] In the diagram: 1. Insulating circuit board; 10. Substrate; 20. Metal layer; 21. Titanium layer; 22. Copper layer; 23. Nickel layer; 24. Gold layer; 25. Platinum layer; 251. Extension area; 30. Pre-formed solder layer. Detailed Implementation

[0023] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0024] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0025] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0026] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0027] To achieve the above objectives, such as Figs. 1-3It is understood that the technical solution adopted in this application is as follows: an insulating circuit board 1, including a substrate 10, a metal layer 20 and a pre-made solder layer 30, the metal layer 20 is disposed between the substrate 10 and the pre-made solder layer 30, the metal layer 20 is provided with a titanium layer 21, a copper layer 22, a nickel layer 23, a gold layer 24 and a platinum layer 25 in sequence from the inside to the outside along a first direction, the length of the platinum layer 25 along a second direction is greater than the length of the pre-made solder layer 30 along the second direction, and the length of the platinum layer 25 along a third direction is not less than the length of the pre-made solder layer 30 along the third direction.

[0028] It is worth noting that when gold migrates into the pre-solder layer 30, there is a risk of forming intermetallic compounds. This contamination of the pre-solder layer 30 can further affect its melting point. For example, when a gold-tin alloy is used in the pre-solder layer 30, the intermetallic compound formed after gold migration into the gold-tin pre-solder layer 30 has a higher melting point than the gold-tin alloy itself. Therefore, in the subsequent soldering process of the insulating circuit board 1, the soldering temperature must be increased to melt the intermetallic compounds and ensure the soldering effect, thus increasing the risk of damage during soldering of the insulating circuit board 1. Furthermore, since the formed intermetallic compounds are brittle, they are prone to microcracks under mechanical stress, which can further lead to interfacial fracture of the solder joint or plating.

[0029] It is understandable that by extending the length of the platinum layer 25 in the second direction to form the extended region 251, and ensuring that the length of the platinum layer 25 in the third direction is not less than the length of the preformed solder layer 30 in the third direction, the blocking effect of the platinum layer 25 on the gold element is further increased, reducing the risk of gold element migration from the gold layer 24 to the preformed solder layer 30, which is beneficial to enhancing the stability and performance of the insulating circuit board 1.

[0030] The first direction is the height direction of the platinum layer 25, the second direction is the length direction of the platinum layer 25, and the third direction is the width direction of the platinum layer 25. It can be understood that the coordinate system can be flexibly set according to actual needs, and there are no restrictions here.

[0031] In some embodiments, the projection of the pre-formed solder layer 30 along the first direction falls within the projection of the platinum layer 25 along the first direction. It is understood that the area of ​​the pre-formed solder layer 30 is smaller than the area of ​​the platinum layer 25, meaning the pre-formed solder layer 30 completely covers the surface of the platinum layer 25. Since direct contact between the pre-formed solder layer 30 and the gold layer 24 may generate intermetallic compounds, the platinum layer 25 is provided as a barrier layer to reduce the risk of interface reactions and improve the performance and stability of the insulating circuit board 1.

[0032] In some embodiments, the projected boundary of the pre-solder layer 30 along the first direction may coincide with the projected boundary of the platinum layer 25 along the first direction; that is, the boundary of the pre-solder layer 30 is in contact with the boundary of the extended region 251. It is understood that the coincidence of interlayer boundaries helps reduce the risk of stress concentration points. Specifically, the direct alignment of the boundary of the platinum layer 25 with the boundary of the pre-solder layer 30 can limit the lateral diffusion of gold elements along the interlayer gap, thereby reducing the possibility of brittle intermetallic compounds forming at the interface.

[0033] In some embodiments, the projected boundary of the pre-formed solder layer 30 along the first direction may not coincide with the projected boundary of the platinum layer 25 along the first direction; that is, the boundary of the pre-formed solder layer 30 does not adhere to the boundary of the extended region 251. It is worth noting that since the length of the platinum layer 25 along the second direction is greater than the length of the pre-formed solder layer 30 along the second direction, the projection of the pre-formed solder layer 30 along the first direction is entirely within the projection of the platinum layer 25 along the first direction. By completely covering the surface of the platinum layer 25 with the pre-formed solder layer 30 in this application, the raised edge structure phenomenon caused by boundary misalignment between layers is avoided, thereby reducing interface stress concentration, preventing cracks during thermal cycling or mechanical vibration, and improving the stability and performance of the insulating circuit board 1.

[0034] In some embodiments, the length of the platinum layer 25 along a third direction is greater than the length of the pre-formed solder layer 30 along a third direction. It is understood that when there is a certain distance between the boundary between the pre-formed solder layer 30 and the platinum layer 25, the difficulty for the gold layer 24 to migrate across the platinum layer 25 to the pre-formed solder layer 30 increases, further reducing the risk of forming brittle intermetallic compounds, thereby increasing the processing stability, usage stability, and performance of the insulating circuit board 1. On the other hand, the wider platinum layer 25 can also more effectively cover the surface of the insulating circuit board 1, thereby reducing the area of ​​the insulating circuit board 1 exposed to the external environment, which is beneficial to improving the usage stability of the insulating circuit board 1.

[0035] In some embodiments, the thickness of the platinum layer 25 is 0.1 μm to 3 μm, specifically, the thickness of the platinum layer 25 is 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, or 3 μm. It is understood that by setting a platinum layer 25 of a predetermined thickness, the migration of gold elements to the pre-formed solder layer 30 is blocked, further increasing the stability and performance of the insulating circuit board 1. On the other hand, a higher thickness of the platinum layer 25 can also enhance the mechanical properties of the insulating circuit board 1.

[0036] In some embodiments, the thickness of the titanium layer 21 is 0.05 μm to 0.2 μm, specifically, the thickness of the titanium layer 21 is 0.05 μm, 0.1 μm, 0.15 μm, or 0.2 μm. As the bonding interface between the copper layer 22 and the substrate 10, the titanium layer 21 further enhances the adhesion of the metal circuitry, while ensuring that the copper layer 22 is firmly attached to the substrate 10, thereby improving the reliability and stability of the insulating circuit board 1. It is understood that when the thickness of the titanium layer 21 is too large, it affects the electrical performance of the insulating circuit board 1, thereby reducing the stability and performance of the insulating circuit board 1 in use. At a predetermined titanium layer 21 thickness, hardness, corrosion resistance, and high-temperature oxidation resistance are also significantly improved, indicating that appropriately increasing the thickness of the titanium layer 21 in the insulating circuit board 1 can improve its mechanical properties and high-temperature resistance.

[0037] In some embodiments, the thickness of the copper layer 22 is 20 μm to 100 μm, specifically, the thickness of the copper layer 22 is 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm. By providing the copper layer 22 as the main conductive layer in the insulating circuit board 1, connection paths are formed between electronic components, thereby realizing the transmission of current and the transmission of signals. Furthermore, since copper is a good thermal conductor, the copper layer 22 helps to conduct heat from the electronic components to the substrate 10, and then dissipate it into the surrounding environment, thereby achieving effective thermal management. At the same time, it can increase the mechanical strength of the insulating circuit board 1, making it more resistant to mechanical shock and vibration, and improving the durability of the insulating circuit board 1.

[0038] In some embodiments, the thickness of the nickel layer 23 is 1 μm to 3 μm, specifically, the thickness of the nickel layer 23 is 1 μm, 1.5 μm, 2 μm, 2.5 μm, or 3 μm. The thickness of the gold layer 24 is 0.3 μm to 3 μm. Specifically, the thickness of the gold layer 24 is 0.3 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, or 3 μm. Since the thickness of the metal layers 20 in the insulating circuit board 1 directly affects its conductivity and thermal conductivity, the selection of the thickness of each metal layer 20 in the insulating circuit board 1 is crucial for ensuring the performance, reliability, and environmental adaptability of the circuit, and is also a key parameter that needs to be precisely controlled in the design and manufacturing of the insulating circuit board 1.

[0039] In some embodiments, the pre-formed solder layer 30 is a gold-tin alloy, with a gold element mass fraction of 70 wt.% to 80 wt.%. It is understood that the gold-tin alloy has excellent electrical conductivity, effectively reducing the resistance of the insulating circuit board 1 and improving current transmission efficiency. This is particularly important for lines requiring high current flow or circuit sections with high resistance requirements. Therefore, the platinum layer 25 extending along the second direction in this application can migrate gold elements from the gold layer 24 to the pre-formed solder layer 30, reducing contamination of the pre-formed solder layer 30 and maintaining good processing performance in subsequent soldering processes, further improving the stability and performance of the insulating circuit board 1.

[0040] In some embodiments, the thickness of the pre-formed solder layer 30 is 2μm to 6μm, specifically, the thickness of the pre-formed solder layer 30 is 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, or 6μm. It is understood that the pre-formed solder layer 30 can be soldered to a variety of materials and possesses good conductivity, mechanical strength, and corrosion resistance, thus making it suitable for most electronic devices.

[0041] In some embodiments, the substrate 10 is aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, zirconium oxide, polyimide, or polytetrafluoroethylene. It is worth noting that aluminum nitride has excellent thermal conductivity, effectively reducing the operating temperature of the insulating circuit board 1 while extending its service life and ensuring the stability of electronic equipment. Silicon carbide also has a high thermal conductivity, therefore, when used in the insulating circuit board 1, it can effectively conduct and dissipate heat, reducing the operating temperature.

[0042] In some embodiments, the platinum layer 25 has a pre-formed solder layer 30 electroplated on its outer surface away from the substrate 10. It is understood that the insulating circuit board 1 proposed in this application is suitable for a variety of applications, including consumer electronics, industrial control, aerospace, and automotive electronics, and has broad application prospects.

[0043] In some embodiments, the distance between the projection of the side edge of the pre-formed solder layer 30 along the second direction and the side edge of the platinum layer 25 along the second direction onto the first direction is 10 μm to 100 μm. Specifically, the distance between the projections is 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm. It is understood that when there is a certain distance between the boundary between the pre-formed solder layer 30 and the platinum layer 25, the difficulty of the gold layer 24 migrating across the platinum layer 25 to the pre-formed solder layer 30 increases, further reducing the risk of generating brittle intermetallic compounds, thereby increasing the processing stability, usage stability, and performance of the insulating circuit board 1. On the other hand, the widened platinum layer 25 can also more effectively cover the surface of the insulating circuit board 1, thereby reducing the area of ​​the insulating circuit board 1 exposed to the external environment, which is beneficial to improving the usage stability of the insulating circuit board 1.

[0044] To achieve the above objectives, the technical solution adopted in this application is: an electronic device, including the insulating circuit board 1 as described above. By incorporating the insulating circuit board 1 provided in this application, good stability and performance can be maintained when applied to various electronic devices, further enhancing the market competitiveness of the electronic devices.

[0045] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. An insulating circuit board, characterized in that, The device includes a substrate, a metal layer, and a pre-formed solder layer. The metal layer is disposed between the substrate and the pre-formed solder layer. The metal layer is provided with a titanium layer, a copper layer, a nickel layer, a gold layer, and a platinum layer in sequence from the inside to the outside along a first direction. The length of the platinum layer along a second direction is greater than the length of the pre-formed solder layer along the second direction, and the length of the platinum layer along a third direction is not less than the length of the pre-formed solder layer along the third direction.

2. The insulating circuit board according to claim 1, characterized in that, The projection of the preformed solder layer along the first direction falls inside the projection of the platinum layer along the first direction.

3. The insulating circuit board according to claim 2, characterized in that, The length of the platinum layer along the third direction is greater than the length of the pre-formed solder layer along the third direction.

4. The insulating circuit board according to claim 1, characterized in that, The thickness of the platinum layer is 0.1 μm to 3 μm.

5. The insulating circuit board according to claim 1, characterized in that, The thickness of the titanium layer is 0.05μm to 0.2μm, the thickness of the copper layer is 20μm to 100μm, the thickness of the nickel layer is 1μm to 3μm, and the thickness of the gold layer is 0.3μm to 3μm.

6. The insulating circuit board according to any one of claims 1-5, characterized in that, The pre-formed solder layer is a gold-tin alloy, and the mass fraction of gold in the pre-formed solder layer is 70 wt.% to 80 wt.%.

7. The insulating circuit board according to claim 6, characterized in that, The thickness of the pre-formed solder layer is 2μm to 6μm.

8. The insulating circuit board according to claim 1, characterized in that, The substrate is aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, zirconium oxide, polyimide, or polytetrafluoroethylene.

9. The insulating circuit board according to claim 6, characterized in that, The platinum layer has the pre-formed solder layer electroplated on its outer surface away from the substrate. The distance between the side edge of the pre-formed solder layer along the second direction and the projection of the side edge of the platinum layer along the second direction in the first direction is 10 μm to 100 μm.

10. An electronic device, characterized in that, Including the insulated circuit board as described in any one of claims 1 to 9.

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