TW202002734A - Manufacturing method of metal-based high-thermal-conduction substrate - Google Patents

Abstract

A metal-based high-thermal-conduction substrate and a manufacturing method thereof are provided. The manufacturing method includes the following steps. First, a metal base is provided. Subsequently, a thermal-conductive insulating layer is formed on the metal base, in which the material of the thermal-conductive insulating layer includes polymer and thermal-conductive dopants, and the thermal conductivity of the thermal-conductive insulating layer ranges from 100 to 400 W/m.K. Thereafter, a surface treatment is performed on a surface of the thermal-conductive insulating layer to roughen the surface and to form a plurality of functional groups on the surface for bonding to metal atoms. After the surface treatment, a metal layer is formed on the thermal-conductive insulating layer.

Description

Metal-based high thermal conductivity substrate and manufacturing method thereof

The invention relates to a high thermal conductivity substrate and a manufacturing method thereof, in particular to a metal-based high thermal conductivity substrate and a manufacturing method.

With the vigorous development of the global electronic technology industry, the demand for printed circuit boards has grown extremely fast. As a result, circuit substrates have become a key component of today's consumer electronic products and related information, communication peripheral products, and LED lighting and LED automotive lighting. However, the circuit board of electronic products always maintains a consistent planar pattern.

With the increasing requirements for the efficiency, speed and appearance of electronic products, there is no doubt that appearance and thermal management are the two major topics that need to be met. Circuit boards in key component positions are naturally required to have more The functionality, including non-planar type and higher thermal conductivity.

The current manufacturing process of the circuit board adopts the hot pressing method, and the metal layer is pasted on the substrate by an insulating adhesive film, and then the circuit pattern is made on the metal layer. This method can only produce planar circuit boards. If non-planar circuit boards need to be produced, the bending method needs to be processed later to achieve the purpose, and in this way, only flexible substrates can be used, depending on the different substrates. Rigidity and toughness specifications, the circuit pattern of the circuit board at this time is likely to be broken.

The contribution to thermal management issues is limited by the hot pressing method of the current circuit board manufacturing process, and the insulating adhesive film that bonds the base material and the metal layer can only abandon the ability of thermal conduction under the requirement of insulation, even On the so-called metal-based circuit board, the thermal conductivity of 2~3W/MK is also the most, which is extremely difficult to meet the increasing heat transfer of electronic products, especially in high-power and automotive LED lighting applications.

The technical problem to be solved by the present invention is how to use a material with better thermal conductivity as the base material for making flat and non-flat circuit boards to make circuitized components.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a method for manufacturing a metal-based high thermal conductivity substrate. The foregoing manufacturing method includes: providing a metal substrate, which may be flat or non-flat; making a high thermal conductivity insulating layer on the substrate, wherein the material of the high thermal conductivity insulating layer includes a high Molecular base material and a thermally conductive dopant, and the thermal conductivity of the thermally conductive insulating layer is between 100 and 400W/m. K; perform a surface treatment on the surface of the thermally conductive insulating layer to roughen the surface of the thermally conductive insulating layer and form a functional group with atomic bonding on the surface to bond with metal atoms; and through electroless plating and electroplating processes A metal layer is on the surface-treated thermally conductive insulating layer, which is used for making circuits.

Another technical solution adopted by the present invention is to provide a metal machine high thermal conductivity substrate, which includes a metal substrate, a thermally conductive insulating layer, and a metal layer. The thermally conductive insulating layer is provided on the metal substrate and includes a polymer base material and a thermally conductive dopant. The thermal conductivity of the thermally conductive insulating layer is between 100 and 400 W/m. K. The metal layer is disposed on the thermally conductive insulating layer, and includes an electroless metal plating layer and an electroplated metal layer. The electroless metal plating layer is disposed between the thermally conductive insulating layer and the electroplated metal layer.

The beneficial effect of the present invention is that in the metal-based high thermal conductivity substrate and the manufacturing method thereof provided by the technical solution of the present invention, a thermally conductive insulating layer with a high thermal conductivity coefficient is fabricated on a metal substrate, and roughening and metal atomic bonding are used. For the surface treatment process of junction efficiency, a metal layer is formed on the insulating layer with high thermal conductivity by electroless plating and electroplating process to make a circuit. The metal-based high thermal conductivity substrate manufactured by the invention can directly and quickly transfer the heat energy generated by the electronic component, and can effectively reduce the working temperature of the electronic product component, thereby increasing the service life of the product.

The thermal conductivity of the thermally conductive insulating layer can be adjusted by the types and proportions of the polymer matrix and impurities used in the production of the insulating layer. The thermal conductivity of the conventional thermally conductive insulating layer is in the range of 100~400w/mk.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and description only, and are not intended to limit the present invention.

P1‧‧‧Metal-based high thermal conductivity substrate

10‧‧‧Metal substrate

10a‧‧‧First surface

10b‧‧‧Second surface

11, 11’‧‧‧ thermal insulation layer

11s‧‧‧Surface

12‧‧‧Protective layer

13’、13‧‧‧Metal layer

130’、130‧‧‧electroless plating metal layer

131, 131’‧‧‧ with electroplated metal layer

S100~S400‧‧‧Process steps

13h‧‧‧ opening pattern

FIG. 1 is a flowchart of a method for manufacturing a metal-based high thermal conductivity substrate according to an embodiment of the invention.

FIG. 2A is a partial cross-sectional schematic diagram of a metal-based high thermal conductivity substrate in a manufacturing process according to an embodiment of the invention.

2B is a partial cross-sectional schematic diagram of a metal-based high thermal conductivity substrate in the manufacturing process according to an embodiment of the invention.

2C is a partial cross-sectional schematic diagram of a metal-based high thermal conductivity substrate in the manufacturing process according to an embodiment of the invention.

FIG. 2D is a partial cross-sectional view of a metal-based high thermal conductivity substrate in the manufacturing process according to an embodiment of the invention.

2E is a partial cross-sectional schematic diagram of a metal-based high thermal conductivity substrate in the manufacturing process according to an embodiment of the invention.

FIG. 2F is a partial cross-sectional schematic diagram of a metal-based high thermal conductivity substrate in a manufacturing process according to an embodiment of the invention.

FIG. 2G is a partial cross-sectional schematic diagram of a metal-based high thermal conductivity substrate in the manufacturing process according to an embodiment of the invention.

2H is a partial cross-sectional schematic diagram of a metal-based high thermal conductivity substrate in the manufacturing process according to an embodiment of the invention.

Please refer to Figure 1. FIG. 1 is a flowchart of a method for manufacturing a metal-based high thermal conductivity substrate according to an embodiment of the invention.

In step S100, a metal substrate is provided. Next, in step S200, a thermally conductive insulating layer is formed on the metal substrate. In step S300, a surface treatment is performed on the thermally conductive insulating layer. Then, in step S400, a metal layer is formed on the thermally conductive insulating layer.

For detailed process steps, please refer to FIGS. 2A to 2H. FIG. 2A to FIG. 2H respectively show partial cross-sectional schematic diagrams of the metal-based high thermal conductivity substrate in different manufacturing steps of the embodiment of the present invention.

First, as shown in FIG. 2A, a metal substrate 10 is provided. The metal substrate 10 may be a flat substrate or a non-flat substrate. The non-plate-shaped substrate is, for example, a substrate having an irregular shape or a concave-convex structure such as a heat sink of an electronic product and a carrier of a semiconductor element.

In this embodiment, the metal substrate 10 is a non-flat substrate and has a first surface 10a and a second surface 10b. It should be noted that in this embodiment, the first surface 10a and the second surface 10b are both uneven surfaces. The aforementioned uneven surface generally refers to a non-flat surface, that is to say, the uneven surface may include a curved surface, an inclined surface, a stepped surface, a concave surface, a convex surface, or any combination of the foregoing. Depending on the shape of the substrate 10, the vertical gap (height difference) between the highest point and the lowest point of the uneven surface may be from 0.01 cm (cm) to 5 cm (cm). In another embodiment, the first surface 10a is an uneven surface, and the second surface 10b is a flat surface.

In addition, the material of the metal substrate 10 may be a metal or an alloy, such as aluminum, copper, iron, tin, nickel, stainless steel, or the like.

Next, as shown in FIG. 2B, a thermally conductive insulating layer 11' is formed on the metal substrate 10. It should be noted that the thermally conductive insulating layer 11' covers at least the area of the metal substrate 10 where the metal layer is to be formed.

For example, when the metal substrate 10 is a heat sink, the aforementioned first surface 10a may be the upper surface of the heat sink, and the second surface 10b is the bottom surface of the heat sink. Therefore, the thermally conductive insulating layer 11' covers the first surface 10a, while the second surface 10b of the base material 10 does not cover the thermally conductive insulating layer 11'.

In another embodiment, the thermally conductive insulating layer 11' may cover all surfaces of the substrate 10 (including the first surface 10a, the second surface 10b, and the side surfaces), but the metal layer formed in the subsequent process is only provided on a part of it On the surface (for example, the first surface 10a).

In addition, in an embodiment, the thermally conductive insulating layer 11 ′ can be formed on the metal substrate 10 using a spraying method, a coating method, or a dip coating method, where the spraying method is, for example, an electrostatic spraying method, a thermal spraying method, or an electric spraying method. The slurry spray method and the like, and the coating method is, for example, a spin coating method, a blade coating method, a brush coating method, and the like. The spraying method can be used to form a relatively uniform thermally conductive insulating layer 11' on the first surface 10, and the spraying method is also suitable for automation and mass production of metal-based high thermal conductivity substrates.

In this embodiment, the thermal conductivity of the thermally conductive insulating layer 11' is between 100 and 400 W/m.K to provide better heat dissipation. Specifically, the material of the thermally conductive insulating layer 11' includes a polymer base material and a thermally conductive dopant. The thermal conductivity of the thermally conductive insulating layer 11' can be adjusted by adjusting the types and ratios of the polymer base material and the thermally conductive dopant.

The polymer base material may be a thermoplastic or thermosetting material. The polymer base material includes, but is not limited to, polyethylene (Polyethylene), polypropylene (Polypropylene), epoxy resin (Epoxy), acrylic resin, polyvinyl chloride (PVC), or any combination thereof. The thermally conductive dopant can be selected from materials with a thermal conductivity coefficient of at least 100 W/mK. The thermally conductive dopant includes, but is not limited to, graphene, graphene derivatives, aluminum nitride, aluminum nitride derivatives, aluminum oxide, and metal powder ( Contains alloy powder) or any combination thereof. In an embodiment, the weight of the thermally conductive dopant is 40 to 70% of the total weight of the thermally conductive insulating layer.

In this embodiment, the thermally conductive insulating layer 11' is formed on a part of the surface of the metal substrate 10 without covering the entire surface of the substrate 10. That is, in this embodiment, the thermally conductive insulating layer 11' is not formed on the other surface 10b of the metal base material 10. In addition, the thickness of the thermally conductive insulating layer 11' is approximately between 100 micrometers (µm) and 200 micrometers (µm). In one embodiment, the height difference of the first surface 10a is at least greater than 0.1 centimeter (cm). Therefore, the surface of the thermally conductive insulating layer 11' has a contour conforming to the first surface 10a.

Referring to FIG. 2C, in order to avoid the second surface 10b of the metal substrate 10 being not covered by the thermally conductive insulating layer 11', it may contact the electroless plating solution and the plating solution in the subsequent manufacturing process. The method for manufacturing a metal-based high thermal conductivity substrate according to an embodiment of the present invention may further include forming a protective layer 12 to cover another part of the surface of the metal substrate 10, that is, the second surface 10b.

The material of the protective layer 12 may be a polymer material. The polymer material may be a thermoplastic or thermosetting polymer material, such as: polyethylene (Polyethylene), polypropylene (Polypropylene), epoxy resin (Epoxy), polyvinyl chloride (PVC), acrylic resin, or any combination thereof. As long as it can be used to protect the metal substrate 10, the invention does not limit the material of the protective layer 12.

The protective layer 12 may be formed on the metal substrate 10 by coating. In addition, it is first explained that the protective layer 12 formed on the metal substrate 10 in this step can be removed in the subsequent step.

In one embodiment, the protective layer 12 and the thermally conductive insulating layer 11' do not overlap each other. In another embodiment, the protective layer 12 and the thermally conductive insulating layer 11' overlap each other at the junction of the two. That is, the edge portion of the protective layer 12 and the edge portion of the thermally conductive insulating layer 11' may overlap each other (not shown).

It should be noted that when the thermally conductive insulating layer 11' completely covers all surfaces of the metal substrate 10, the step of forming the protective layer 12 may also be omitted.

Next, as shown in FIG. 2D, a surface treatment is performed on the thermally conductive insulating layer 11' to roughen a surface 11s of the thermally conductive insulating layer 11 and form a functional group with atomic bonding on the surface for bonding with metal atoms .

Specifically, in this embodiment, a surface treatment liquid is used to roughen the surface 11s of the thermally conductive insulating layer 11 and modify the surface 11s. According to this, after surface pretreatment, the surface roughness of surface 11s is between 0.1 μm and 1 μm.

Further, in one embodiment, after performing the surface pretreatment step, the surface 11s will have a plurality of micro holes. In addition, in this embodiment, the pore size of the micropores is between 0.01 micrometer (μm) and 5 micrometer (μm).

In addition, the surface treatment liquid can also be used to modify the surface 11s, and a functional group capable of bonding to metal atoms can be formed on the surface 11s. The functional groups formed on the plurality of micropores hole, and the functional group may contain at least one anionic and cationic, eg, containing: chloride ion (Cl ^-), sulfite ion (SO ₃ ^-), nitrate ion ( NO ₃ ^-), bromide ion (Br ^-), a combination of sodium ions (Na ^+), potassium ion (K ^+), or any. In one embodiment, the surface treatment liquid with a surfactant is used to modify the surface 11s, and the surfactant contains the functional groups listed above. It should be noted that the surface 11s is an area where a metal layer is to be formed in the subsequent process. That is, the roughened surface 11s may be all the outer surfaces of the thermally conductive insulating layer 11' or a part of the outer surfaces of the thermally conductive insulating layer 11'.

For example, when the thermally conductive insulating layer 11 is formed on all surfaces of the metal substrate 10 (including the first surface 10a, the second surface 10b, and the side surfaces), and in the subsequent process, only the metal layer is formed on the first surface 10a At this time, the outer surface of only part of the thermally conductive insulating layer 11' covering the first surface 11a is defined as the surface 11s to be plated. That is to say, only a part of the outer surface (surface to be plated 11 s) of the thermally conductive insulating layer 11 will be roughened, and the other part of the outer surface will not be specially surface-treated. Therefore, after the surface treatment, the outer surface of the thermally conductive insulating layer 11 will have different surface roughness in different regions. The portion of the thermally conductive insulating layer 11 that has not undergone surface pretreatment will not form a metal layer in subsequent steps, and thus can be used to protect the metal substrate 10.

Next, as shown in FIGS. 2E to 2H, a metal layer is formed on the thermally conductive insulating layer 11 to fabricate a circuit. Specifically, as shown in FIG. 2E, an electroless metal plating layer 130' is first formed on the surface 11s of the thermally conductive insulating layer 11 to be plated. That is, the aforementioned electroless plating metal layer 130' is first formed by an electroless plating method. The material of the electroless plating metal layer 130' may be conductive materials such as copper, aluminum, nickel, gold, and the like. In addition, the thickness of the electroless metal plating layer 130' is approximately 0.3 to 0.6 micrometers (µm).

Subsequently, as shown in FIG. 2F, an electroplated metal layer 131' is formed on the electroless plated metal layer 130', and the thickness of the electroplated metal layer 131' exceeds at least 20 micrometers (µm). That is, after the electroless plating method is performed, the electroplating method is performed to increase the total thickness of the metal layer. The electroless plated metal layer 130' and the electroplated metal layer 131' together form a metal layer 13'. In this embodiment, the metal layer 13' covers the entire surface 11s of the thermally conductive insulating layer 11.

It should be noted that, in this embodiment, before forming the electroless plating metal layer 130', the thermally conductive insulating layer 11 is surface-treated to form a rough surface 11s, and an atomic bond is formed on the rough surface 11s Functional group for bonding to metal atoms. The rough surface 11s can further increase the surface area for forming functional groups, and the rough surface 11s can also increase the bonding force between the metal and the thermally conductive insulating layer 11.

Therefore, the adhesion between the metal layer 13' and the thermally conductive insulating layer 11 can be further improved. In this way, the probability of the metal layer 13' falling off from the metal substrate 10 can be reduced, and the product yield can be improved. In one embodiment, the adhesion of the metal layer 13' is at least 1.2 kg, which can meet current circuit board inspection specifications.

In addition, when the electroplated metal layer 131' is formed by the electroplating method, the entire metal substrate 10 must be immersed in the plating solution. Since the material of the metal substrate 10 in this embodiment is a metal material, the protective layer 12 formed in the previous step (FIG. 2C) can isolate the metal substrate 10 from the plating solution.

Next, referring to FIG. 2G, after the preparation of the electroplated metal layer 131' is completed, the protective layer 12 is removed. In one embodiment, the protective layer 12 can be peeled directly from the metal substrate 10. In other embodiments, the protective layer 12 can also be removed by a chemical solution.

Referring to FIG. 2H, the electroless plated metal layer 130' and the electroplated metal layer 131' are patterned to form a circuitized metal layer 13. Through the above steps, the metal-based high thermal conductivity substrate P1 according to one embodiment of the present invention can be formed.

In one embodiment, the patterned electroless plated metal layer 130' and the electroplated metal layer 131' can be implemented using existing steps of coating photoresist, lithography, etching, etc., so that the circuitized metal layer 13 has a predetermined pattern. In another embodiment, laser engraving may be used to pattern the electroless plated metal layer 130' and the electroplated metal layer 131'.

In this embodiment, the patterned electroless plated metal layer 130 and the patterned electroplated metal layer 131 together form the circuitized metal layer 13. The circuitized metal layer 13 has an opening pattern 13h, and a part of the surface of the thermally conductive insulating layer 11 is exposed through the opening pattern 13h.

After the metal layers 13' and 13 are completed, a solder mask, a plurality of terminals for connecting external circuits, and a de-panel can be further formed on the metal-based high thermal conductivity substrate P1 ) And other processes.

In summary, the beneficial effect of the present invention lies in the metal-based high thermal conductivity substrate and the manufacturing method thereof provided by the technical solution of the present invention, by "forming a thermally conductive insulating layer 11 with a thermal conductivity coefficient between 100 and 400 W/mK on the metal substrate 10 , Perform a surface pre-treatment on the thermally conductive insulating layer 11 and then form the metal layers 13', 13" on the thermally conductive insulating layer 11, the metal layers 13', 13 can be formed directly on the surface of the three-dimensional metal substrate 10 And, the metal-based high thermal conductivity substrate P1 has a good thermal conductivity effect.

It should be noted that in the prior art means, the circuit board body formed by pressing can only be formed into a flat plate shape, and cannot have a three-dimensional structure. Compared with the previous technical means, the manufacturing method provided in the embodiments of the present invention can form metal layers 13', 13 on a substrate having an arbitrary shape.

Accordingly, through the manufacturing method provided by the embodiments of the present invention, heat dissipation parts of electronic products, components, semiconductor component carriers, connectors, and other parts with irregular shapes can be directly used as the metal substrate 10, and the metal The layer 13' is directly formed on the metal substrate 10 for making circuits. In this way, the electronic component can be directly soldered on the metal layers 13', 13 and the existing flat-shaped circuit board or flexible circuit board can be omitted, thereby reducing the volume of the electronic product.

In addition, the thermal conductivity of the thermally conductive insulating layer 11 in the embodiment of the present invention is higher than that of the insulating material (glass fiber adhesive film board) used in the existing circuit board. When the metal-based high thermal conductivity substrate P1 of this embodiment operates in conjunction with electronic components mounted thereon, the thermally conductive insulating layer 11 can provide better thermal conductivity.

Further, when the material of the metal substrate 10 is aluminum, the thermal conductivity coefficient (K value) of the entire metal substrate 10 coated with the thermally conductive insulating layer 11 can be as high as 150 W/m. K is 75 times that of commercially available aluminum substrates. When the material of the metal substrate 10 is copper, the thermal conductivity coefficient (K value) of the entire metal substrate 10 coated with the thermally conductive insulating layer 11 can be as high as 350 W/m. K.

The metal-based high thermal conductivity substrate P1 manufactured by the invention can directly and quickly transfer the heat energy generated by the electronic components, and can effectively reduce the working temperature of the electronic product components, thereby increasing the service life of the products.

In addition, the thermal conductivity of the thermally conductive insulating layer 11 can be adjusted by adjusting the types and ratios of the polymer base material and the dopant. The thermal conductivity of the thermally conductive insulating layer 11 under conventional conditions ranges from 100 to 400 w/mk.

The content disclosed above is only a preferred and feasible embodiment of the present invention, and does not limit the scope of the patent application of the present invention, so all equivalent technical changes made by using the description and drawings of the present invention are included in the application of the present invention. Within the scope of the patent.

S100~S400‧‧‧Process steps

Claims (11)

A method for manufacturing a metal-based high thermal conductivity substrate includes: providing a metal substrate; making a thermally conductive insulating layer on the metal substrate, wherein the material of the thermally conductive insulating layer includes a polymer base material and a thermal conductor Dopants, and the thermal conductivity of the thermally conductive insulating layer is between 100 to 400W/m. K; performing a surface treatment on a surface of the thermally conductive insulating layer to roughen the surface of the thermally conductive insulating layer, and forming a functional group having atomic bonding on the surface to bond with metal atoms; and making A metal layer is on the thermally-conductive insulating layer treated by the surface. The manufacturing method according to claim 1, wherein the step of forming the metal layer further comprises: forming an electroless plating metal layer on the thermally conductive insulating layer; and forming an electroplated metal layer on the electroless plating On the metal layer, the thickness of the electroplated metal layer is greater than the thickness of the electroless plated metal layer. The manufacturing method according to claim 2, wherein the step of forming the metal layer further comprises: patterning the electroless plated metal layer and the electroplated metal layer. The manufacturing method according to claim 2, wherein the thermally conductive insulating layer covers a part of the surface of the substrate, and before the step of forming the electroless metal plating layer, a protective layer is formed to cover the substrate Another part of the surface; and after the step of forming the electroplated metal layer, removing the protective layer. The manufacturing method according to claim 1, wherein the metal substrate is a flat substrate or a non-flat substrate, and the thermally conductive insulating layer is directly formed on the metal substrate. The manufacturing method according to claim 1, wherein the thermal conductivity of the thermally conductive dopant is at least greater than 100W/m. K, and the weight of the thermally conductive dopant accounts for 40 to 70% of the total weight of the thermally conductive insulating layer. The manufacturing method according to claim 1, wherein the polymer base material comprises polyethylene, polypropylene, epoxy resin, acrylic resin, polyvinyl chloride (PVC), or any combination thereof, and the thermal conductivity The dopant includes graphene, graphene derivatives, aluminum nitride, aluminum nitride, aluminum nitride derivatives, aluminum oxide, metal powder, or any combination thereof. The manufacturing method of claim 7 requests, wherein said plurality of functional groups are formed on the microporous hole, and the functional group-containing ions comprising chloride (Cl ^-), sulfite ion (SO ₃ ^-) , ₍₃ NO ^-) nitrate ion, a bromine ion (Br ^-), a combination of sodium ions (Na ^+), potassium ion (K ^+), or any. A metal-based high thermal conductivity substrate includes: a metal substrate; a thermally conductive insulating layer, which is disposed on the metal substrate, wherein the material of the thermally conductive insulating layer includes a polymer base material and a thermally conductive doping Thing, and the thermal conductivity of the thermally conductive insulating layer is between 100 to 400W/m. K; and a metal layer disposed on the thermally conductive insulating layer, wherein the metal layer includes an electroless metal plating layer and an electroplated metal layer, the electroless metal plating layer is disposed on the thermally conductive insulating layer With the electroplated metal layer. The metal-based high thermal conductivity substrate according to claim 9, wherein the metal substrate is a flat substrate or a non-flat substrate, and the thermally conductive insulating layer is directly formed on the surface of the metal substrate. The metal-based high thermal conductivity substrate according to claim 9, wherein the polymer base material comprises polyethylene, polypropylene, epoxy resin, polyvinyl chloride (PVC) or any combination thereof, and the thermally conductive dopant Contains graphene, graphene derivatives, aluminum nitride, aluminum nitride derivatives, aluminum oxide, metal powder, or any combination thereof.

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