Insulated wiring board and electronic device thereof

Abstract

The application discloses an insulating circuit board, which comprises a bottom plate, a metal layer and a pre-plated solder layer arranged in sequence from inside to outside, the metal layer comprises a palladium layer and a gold layer, the palladium layer is arranged on the side close to the bottom plate, the gold layer is arranged on the side close to the pre-plated solder layer, the thickness of the palladium layer is 0.05-1 mu m, and the thickness of the gold layer is 0.05-2 mu m. The insulating circuit board provided by the application is favorable for reducing the risk of mutual migration of nickel elements and gold elements, avoiding the generation of 'black nickel' or 'black pad' in the insulating circuit board, and further improving the quality of the insulating circuit board. On the other hand, the application provides an insulating circuit board and an electronic device, which are favorable for reducing the production cost, enhancing the use stability and service life, increasing the economic benefits, and further widening the application scenarios 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 gold and nickel layers are commonly used in insulated circuit boards, nickel migration often occurs during processing, resulting in "black nickel" or "black pads" on the circuit board. This further affects the stability of signal and power transmission and the bonding strength and reliability of the packaged wire bonding. On the other hand, the use of gold layers further increases production costs and reduces economic efficiency. Summary of the Invention

[0005] One objective of this application is to provide an insulating circuit board and its electronic equipment, which helps to reduce the risk of intermigration between nickel and gold elements, avoid the formation of "black nickel" or "black pad" in the circuit board, improve the quality of the insulating circuit board, and enhance its stability and service life.

[0006] Another objective of this application is to provide an insulated circuit board and electronic equipment thereof, which helps to reduce production costs and increase economic benefits.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows: an insulating circuit board, comprising a base plate, a metal layer, and a pre-plated solder layer arranged sequentially from the inside out, wherein the metal layer comprises a palladium layer and a gold layer, wherein the palladium layer is disposed near the base plate, and the gold layer is disposed near the pre-plated solder layer; and

[0008] The thickness of the palladium layer is 0.05 μm to 1 μm, and the thickness of the gold layer is 0.05 μm to 2 μm.

[0009] In some embodiments, the insulating circuit board further includes a titanium layer, a copper layer, a nickel layer, and a platinum layer, wherein the titanium layer, the copper layer, the nickel layer, the palladium layer, the gold layer, and the platinum layer are disposed sequentially; the titanium layer is disposed on the side close to the base plate, and the platinum layer is disposed on the side close to the pre-plated solder layer.

[0010] In some embodiments, the length of the platinum layer along the second direction is greater than the length of the pre-plated solder layer along the second direction, and the length of the platinum layer along the third direction is not less than the length of the pre-plated solder layer along the third direction.

[0011] In some embodiments, the projection of the pre-plated solder layer along the first direction falls inside the projection of the platinum layer along the first direction.

[0012] In some embodiments, the thickness of the titanium layer is 0.05 μm to 0.2 μm, the thickness of the copper layer is 3 μm to 100 μm, the thickness of the nickel layer is 1 μm to 3 μm, and the thickness of the gold layer is 0.1 μm to 1 μm.

[0013] In some embodiments, the thickness of the platinum layer is 0.1 μm to 3 μm, and the thickness of the pre-plated solder layer is 2 μm to 6 μm.

[0014] In some embodiments, the pre-plated solder layer is a gold-tin alloy, and the mass fraction of gold in the pre-plated solder layer is 70 wt.% to 85 wt.%.

[0015] In some embodiments, the base plate is aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, zirconium oxide, polyimide, polytetrafluoroethylene, boron nitride, diamond, or a diamond film.

[0016] In some embodiments, the thickness of the palladium layer is 0.1 μm to 1 μm, and the thickness of the gold layer is 0.1 μm to 1 μm.

[0017] 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.

[0018] Compared with the prior art, the beneficial effects of this application are as follows:

[0019] (1) By setting a palladium layer between the nickel layer and the gold layer, the risk of mutual migration between nickel and gold elements is reduced, and the phenomenon of "black nickel" or "black pad" in the circuit board is avoided, which further improves the quality of the insulated circuit board, thereby enhancing the stability of signal and power transmission, improving the bonding strength and reliability of the packaged wire bonding, and enhancing the stability and service life. On the other hand, the palladium layer can provide additional protection for the gold layer, preventing the gold layer from being damaged locally due to wear or scratches.

[0020] (2) By reducing the thickness of the gold layer and replacing part of the gold layer with a palladium layer, the cost of production can be reduced and the economic benefits can be improved. Attached Figure Description

[0021] Figure 1 This is a front view schematic diagram of the layered structure of an insulating circuit board according to some embodiments of this application.

[0022] Figure 2 This is a three-dimensional structural schematic diagram of an insulating circuit board according to some embodiments of this application.

[0023] Figure 3 This is a top view of the three-dimensional structure of an insulating circuit board according to some embodiments of this application.

[0024] In the diagram: 1. Insulating circuit board; 10. Base plate; 20. Metal layer; 21. Titanium layer; 22. Copper layer; 23. Nickel layer; 24. Palladium layer; 25. Gold layer; 26. Platinum layer; 30. Pre-plated solder layer. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] To achieve the above objectives, the technical solution adopted in this application is as follows: an insulating circuit board 1, comprising a base plate 10, a metal layer 20, and a pre-plated solder layer 30 arranged sequentially from the inside out. The metal layer 20 includes a palladium layer 24 and a gold layer 25, wherein the palladium layer 24 is disposed on the side closer to the base plate 10, and the gold layer 25 is disposed on the side closer to the pre-plated solder layer 30; and

[0030] The palladium layer 24 has a thickness of 0.05 μm to 1 μm, specifically, the thicknesses are 0.05 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, and 1 μm. The gold layer 25 has a thickness of 0.05 μm to 2 μm, specifically, the thicknesses are 0.05 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, and 2 μm. (Reference) Figure 1 As shown, the palladium layer 24 provided between the nickel layer 23 and the gold layer 25 in the metal layer 20 above the base plate 10 helps to prevent nickel metal in the nickel layer 23 from migrating to the gold layer 25 and being oxidized to form a thin film containing nickel oxide during high-temperature processing. This further prevents the insulation circuit board 1 from experiencing a decrease in conductivity and a decrease in corrosion resistance, thereby enhancing the stability of signal and power transmission in the insulation circuit board 1, improving the bonding strength and reliability of the packaging wire bonding, reducing the amount of gold used in production, further reducing consumption costs in the production process, and extending the service life of electronic equipment.

[0031] On the one hand, since the palladium layer 24 can reduce the thickness of the gold layer 25, it is understandable that the manufacturing cost of the gold layer 25 is relatively high. Therefore, reducing the thickness of the gold layer 25 helps to reduce the overall cost of the insulating circuit board 1, thereby increasing economic benefits and market competitiveness. On the other hand, the palladium layer 24 can provide additional protection for the gold layer 25, preventing localized damage to the gold layer 25 due to wear or scratches, further enhancing the stability and service life of the insulating circuit board 1.

[0032] In some embodiments, the insulating circuit board 1 further includes a titanium layer 21, a copper layer 22, a nickel layer 23, and a platinum layer 26, wherein the titanium layer 21, copper layer 22, nickel layer 23, palladium layer 24, gold layer 25, and platinum layer 26 are arranged sequentially; the titanium layer 21 is disposed near the base plate 10, and the platinum layer 26 is disposed near the pre-plated solder layer 30. It is worth noting that the high hardness of the titanium layer 21 provides wear and scratch resistance, thereby protecting the internal structure of the insulating circuit board 1. The copper layer 22 has low resistance, which is beneficial for enhancing efficient signal transmission, further reducing energy loss, and improving signal transmission speed and quality. The nickel layer 23 can prevent the copper layer 22 from being oxidized during subsequent electroplating, ensuring that the conductivity and solderability of the copper layer 22 are not affected. The platinum layer 26 has good conductivity, which can effectively reduce the contact resistance of the insulating circuit board 1, ensuring the stability and reliability of signal transmission. This is particularly important for the application of the insulating circuit board 1 in high-speed signal transmission and high-precision electronic equipment.

[0033] like Figure 2 As shown, in some embodiments, the length of the platinum layer 26 along the second direction is greater than the length of the pre-plated solder layer 30 along the second direction, and the length of the platinum layer 26 along the third direction is not less than the length of the pre-plated solder layer 30 along the third direction. It is understood that by extending the length of the platinum layer 26 in the second direction to form an extended region, and by ensuring that the length of the platinum layer 26 along the third direction is not less than the length of the pre-plated solder layer 30 along the third direction, the blocking effect of the platinum layer 26 on gold elements is further increased, reducing the risk of gold elements migrating from the gold layer 25 to the pre-plated solder layer 30, which is beneficial to enhancing the stability and performance of the insulating circuit board 1.

[0034] The first direction is the height direction of the platinum layer 26, the second direction is the length direction of the platinum layer 26, and the third direction is the width direction of the platinum layer 26. It can be understood that the coordinate system can be flexibly set according to actual needs, and there are no restrictions here.

[0035] like Figure 3As shown, in some embodiments, the projection of the pre-plated solder layer 30 along the first direction falls within the projection of the platinum layer 26 along the first direction. It is understood that the area of ​​the pre-plated solder layer 30 is smaller than the area of ​​the platinum layer 26, meaning the pre-plated solder layer 30 completely covers the surface of the platinum layer 26. Since direct contact between the pre-plated solder layer 30 and the gold layer 25 may generate intermetallic compounds, the platinum layer 26 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.

[0036] In some embodiments, the projected boundary of the pre-plated solder layer 30 along the first direction may coincide with the projected boundary of the platinum layer 26 along the first direction; that is, the boundary of the pre-plated solder layer 30 is in contact with the boundary of the extended region. 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 26 with the boundary of the pre-plated 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.

[0037] In some embodiments, the projected boundary of the pre-plated solder layer 30 along the first direction may not coincide with the projected boundary of the platinum layer 26 along the first direction; that is, the boundary of the pre-plated solder layer 30 does not adhere to the boundary of the extended region. It is worth noting that since the length of the platinum layer 26 along the second direction is greater than the length of the pre-plated solder layer 30 along the second direction, the projection of the pre-plated solder layer 30 along the first direction is entirely within the projection of the platinum layer 26 along the first direction. By completely covering the surface of the platinum layer 26 with the pre-plated 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.

[0038] In some embodiments, the length of the platinum layer 26 along a third direction is greater than the length of the pre-plated solder layer 30 along a third direction. It is understood that when there is a certain distance between the boundary between the pre-plated solder layer 30 and the platinum layer 26, the difficulty of the gold layer 25 migrating across the platinum layer 26 to the pre-plated 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 26 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.

[0039] 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.

[0040] In some embodiments, the thickness of the copper layer 22 is 3μm to 100μm, specifically, the thickness of the copper layer 22 is 3μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, or 100μm. 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 base plate 10 and 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.

[0041] 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. 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. It is understood that the selection of the thickness of the nickel layer 23 has a significant impact on the reliability and service life of the insulating circuit board 1. When the thickness of the nickel layer 23 is too low, copper may diffuse through the nickel layer 23, thereby affecting the soldering performance and further increasing the risk of copper diffusion. When the thickness of the nickel layer 23 is too high, it may lead to increased production costs and unnecessary material waste.

[0042] In some embodiments, the thickness of the gold layer 25 is 0.1 μm to 1 μm, specifically, the thickness of the gold layer 25 is 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, or 1 μm. The nickel layer 23 disposed between the gold layer 25 and the copper layer 22 helps to significantly increase the mechanical strength of the gold layer 25. Furthermore, because the gold layer 25 has good conductivity and oxidation resistance, it effectively reduces contact resistance, thereby improving the reliability of the connection and enhancing the stability and reliability of the circuit board in application.

[0043] In some embodiments, the thickness of the platinum layer 26 is 0.1 μm to 3 μm, specifically, the thickness of the platinum layer 26 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 26 of a predetermined thickness, the migration of gold elements to the pre-plated 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 26 can also enhance the mechanical properties of the insulating circuit board 1.

[0044] In some embodiments, the thickness of the pre-plated solder layer 30 is 2μm to 6μm, specifically, the thickness of the pre-plated solder layer is 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, or 6μm. It is understood that the pre-plated 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.

[0045] In some embodiments, the pre-plated solder layer 30 is a gold-tin alloy, and the mass fraction of gold in the pre-plated solder layer 30 is 70 wt.% to 85 wt.%. It is understood that the gold-tin alloy has excellent electrical conductivity, which can effectively reduce the resistance of the insulating circuit board 1 and improve current transmission efficiency. This is particularly important for circuits requiring high current flow or circuit sections with high requirements for low resistance. Therefore, the palladium layer 24 provided in this application can prevent nickel from migrating from the nickel layer 23 to the gold layer 25, reducing contamination of the gold layer 25, thereby maintaining good processing performance in subsequent soldering processes and further improving the stability and performance of the insulating circuit board 1.

[0046] In some embodiments, the base plate 10 is aluminum nitride, silicon carbide, alumina, silicon nitride, zirconium oxide, polyimide, polytetrafluoroethylene, boron nitride, diamond, or a diamond film. It is worth noting that aluminum nitride, boron nitride, diamond, and diamond films have 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, thus effectively conducting and dissipating heat when applied to the insulating circuit board 1, reducing the operating temperature. Alumina has a low cost, is suitable for mass production, is widely used in the electronics industry, and has high bending strength, stable chemical properties, and stable performance in various environments. Silicon nitride has excellent wear resistance, which helps extend the service life of the circuit board. Zirconia provides excellent mechanical support and electrical insulation properties, and its excellent thermal shock resistance allows it to withstand sudden temperature changes, making it suitable for working environments with large temperature variations. Polyimide maintains stable performance in high-temperature and chemically corrosive environments. Polytetrafluoroethylene (PTFE) has a low dielectric constant and a low loss factor, which is beneficial for improving signal transmission speed and quality and reducing signal loss.

[0047] In some embodiments, the thickness of the palladium layer 24 is 0.1 μm to 1 μm, specifically, the thickness of the palladium layer 24 is 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, or 1 μm. The thickness of the gold layer 25 is 0.1 μm to 1 μm, specifically, the thickness of the gold layer 25 is 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, or 1 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.

[0048] To achieve the above objectives, the technical solution adopted in this application is: an electronic device including any of the insulating circuit boards 1 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.

[0049] 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 components include, from the inside out, a base plate, a metal layer, and a pre-plated solder layer. The metal layer comprises a palladium layer and a gold layer, wherein the palladium layer is disposed near the base plate, and the gold layer is disposed near the pre-plated solder layer. The thickness of the palladium layer is 0.05 μm to 1 μm, and the thickness of the gold layer is 0.05 μm to 2 μm.

2. The insulating circuit board as described in claim 1, characterized in that, The insulating circuit board further includes a titanium layer, a copper layer, a nickel layer, and a platinum layer, wherein the titanium layer, the copper layer, the nickel layer, the palladium layer, the gold layer, and the platinum layer are arranged sequentially; the titanium layer is disposed on the side closer to the base plate, and the platinum layer is disposed on the side closer to the pre-plated solder layer.

3. The insulating circuit board as described in claim 2, characterized in that, The thickness of the titanium layer is 0.05μm to 0.2μm, the thickness of the copper layer is 3μm to 10μm, the thickness of the nickel layer is 1μm to 3μm, and the thickness of the gold layer is 0.1μm to 1μm.

4. The insulating circuit board as described in claim 2, characterized in that, The thickness of the platinum layer is 0.1μm to 3μm, and the thickness of the pre-plated solder layer is 2μm to 6μm.

5. The insulating circuit board according to claim 1, characterized in that, The base plate is made of aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, zirconium oxide, polyimide, polytetrafluoroethylene, boron nitride, diamond, or a diamond film.

6. The insulating circuit board as described in claim 2, characterized in that, The length of the platinum layer along the second direction is greater than the length of the pre-plated solder layer along the second direction, and the length of the platinum layer along the third direction is not less than the length of the pre-plated solder layer along the third direction.

7. The insulating circuit board as described in claim 6, characterized in that, The projection of the pre-plated solder layer along the first direction falls inside the projection of the platinum layer along the first direction.

8. The insulating circuit board according to claim 1, characterized in that, The thickness of the palladium layer is 0.1 μm to 1 μm, and the thickness of the gold layer is 0.1 μm to 1 μm.

9. An electronic device, characterized in that, Including the insulated circuit board as described in any one of claims 1 to 8.

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