Manufacturing method of multi-layer aluminum substrate

Abstract

The invention discloses a manufacturing method of a multi-layer aluminum substrate. An inner layer core board is taken, an inner layer circuit is manufactured, and a first circuit layer is formed; a first insulating layer and a second insulating layer are stacked on the two sides of the first circuit layer respectively; a first aluminum plate and a second aluminum plate are provided, rivet holes are formed in the inner layers of the first aluminum plate and the second aluminum plate, and wire drawing treatment is conducted on the outer layers; a first aluminum plate and a second aluminum plate are stacked on the first insulating layer and the second insulating layer respectively; respectively stacking a third insulating layer and a fourth insulating layer on the outer sides of the first aluminum plate and the second aluminum plate, and respectively stacking a first copper foil layer and a second copper foil layer on the other sides of the third insulating layer and the fourth insulating layer; sequentially carrying out primary pressing, edge milling, drilling, copper deposition, electroplating and circuit processes on the multi-layer board to form a second circuit layer and a third circuit layer; taking a third aluminum plate, and bonding and fixing the third aluminum plate with the second circuit layer or the third circuit layer; and carrying out secondary pressing, surface treatment and forming to obtain the multi-layer aluminum substrate. According to the manufacturing method of the multi-layer aluminum substrate provided by the invention, the obtained multi-layer aluminum substrate can provide more wiring space, so that the circuit board is suitable for complex circuit design.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing technology, and specifically to a method for manufacturing a multilayer aluminum substrate. Background Technology

[0002] With the rapid development of the electronics industry, electronic products are becoming smaller and smaller while their power density is increasing. Finding the optimal methods for heat dissipation and structural design has become a major challenge in today's electronics industry. Based on the development of next-generation information technology, audio equipment, energy-saving and new energy vehicles, and power equipment, solving the heat dissipation problem is urgent. Aluminum substrates are undoubtedly one of the effective means to solve the heat dissipation problem because aluminum has a high thermal conductivity and excellent heat dissipation properties, allowing it to quickly dissipate internal heat.

[0003] Aluminum-based copper-clad laminates are a unique type of metal-based material with excellent thermal conductivity, electrical insulation, and machinability. Existing single-layer aluminum-based laminates consist of three layers: an aluminum substrate, an insulating layer, and copper foil. The aluminum substrate is responsible for heat dissipation, the insulating layer conducts heat, and the copper foil is the conductive layer. Current single-layer aluminum-based laminates are only suitable for simple circuit designs, primarily focusing on improving thermal conductivity, reducing resistance, and enhancing reliability. Single-layer aluminum-based laminates offer limited wiring space, and with the continuous development of electronic devices and the expansion of application areas, they can no longer meet the design requirements of complex circuits.

[0004] The purpose of this invention is to provide a multilayer aluminum substrate to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for manufacturing a multilayer aluminum substrate, which can provide more wiring space and make the circuit board adaptable to complex circuit designs.

[0006] The technical solution of the present invention is as follows:

[0007] A method for manufacturing a multilayer aluminum substrate includes the following steps:

[0008] Step S1: Take the inner core board, fabricate the inner layer circuitry, and form the first circuit layer;

[0009] Step S2: Stack the first insulating layer and the second insulating layer on both sides of the first circuit layer, respectively.

[0010] Step S3: Provide a first aluminum plate and a second aluminum plate, drill holes using a drilling coefficient that is consistent with the expansion and contraction coefficient of the inner core board, plug the holes with resin after drilling, and make rivet holes in the inner layer of the first aluminum plate and the second aluminum plate, and perform wire drawing on the outer layer.

[0011] Step S4: Stack the first aluminum plate and the second aluminum plate on the first insulating layer and the second insulating layer respectively, and rivet the first aluminum plate, the first circuit layer and the second aluminum plate together with rivets.

[0012] Step S5: A third insulating layer and a fourth insulating layer are stacked on the outer sides of the first aluminum plate and the second aluminum plate, respectively, and a first copper foil layer and a second copper foil layer are stacked on the other side of the third insulating layer and the fourth insulating layer, respectively.

[0013] Step S6: The multilayer board from step S5 is sequentially laminated, routerd, drilled, copper plated, electroplated, and processed with circuitry to form the second circuitry layer from the first copper foil layer and the third circuitry layer from the second copper foil layer. Solder resist and text printing processes are then applied to the second circuitry layer.

[0014] Step S7: Take the third aluminum plate and brush one side of its surface. The brushed side of the third aluminum plate is then bonded and fixed to the third circuit layer.

[0015] Step S8: Perform a second pressing and screen print blue adhesive on the other side of the third aluminum plate;

[0016] Step S9: Surface treatment and molding to obtain a multilayer aluminum substrate.

[0017] Further, in step S1, the bottom copper on one side of the inner core board is etched away, and the inner circuit is made on the other side to form the first circuit layer.

[0018] Furthermore, the first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer are PP material layers.

[0019] Furthermore, in step S6, during the pressing process, the plates are stacked in the order of steel plate / buffer pad / multilayer board / buffer pad / steel plate, wherein the buffer pad includes a first PET layer, a PE / PO layer and a second PET layer stacked sequentially.

[0020] Furthermore, before the second lamination, the surface of the second circuit layer is treated with high-temperature adhesive and then browned.

[0021] Furthermore, in step S8, during the secondary pressing, release films are applied to the upper and lower surfaces of the multilayer board.

[0022] Compared with the prior art, the method for fabricating a multilayer aluminum substrate provided by the present invention has the following advantages:

[0023] The method for manufacturing a multilayer aluminum substrate provided by this invention increases the number of aluminum substrate layers (serving as heat dissipation layers) and the number of circuit layers, providing more wiring space, suitable for complex circuit designs, and providing an independent layer for grounding power supply. This reduces the possibility of simultaneous antenna radiation in the circuit, improves signal transmission speed, reduces interference, and enhances electromagnetic interference resistance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the buffer pad structure used in the first pressing step in the manufacturing method of the multilayer aluminum substrate of the present invention.

[0026] Figure 2 This is a schematic diagram of the structure of the multilayer aluminum substrate obtained by the manufacturing method of the multilayer aluminum substrate of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below.

[0028] It should be noted that the descriptions of these embodiments are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] A method for manufacturing a multilayer aluminum substrate includes the following steps:

[0030] Step S1: Take the inner core board, fabricate the inner layer circuitry, and form the first circuit layer;

[0031] In this process, the copper on one side of the inner core board is etched away, while the other side is used to create the inner layer circuitry, forming the first circuit layer. Then, it undergoes inner layer AOI, OPE punching, and browning treatment. Because the inner core board forms the first circuit layer, it can serve as an independent grounding power supply layer. Furthermore, the mixing of aluminum substrate and FR4 in this invention provides better insulation for the independent grounding power supply layer, resulting in improved product reliability.

[0032] Step S2: A first insulating layer and a second insulating layer are stacked on both sides of the first circuit layer, respectively; specifically, the first insulating layer and the second insulating layer are PP material layers.

[0033] Step S3: Provide a first aluminum plate and a second aluminum plate, drill holes using a drilling coefficient that is consistent with the expansion and contraction coefficient of the inner core board, plug the holes with resin after drilling, and make rivet holes in the inner layers of the first aluminum plate and the second aluminum plate. In order to enhance the bonding force between the circuit layer and the outer layer of the aluminum plate during the pressing process, improve the peel strength, and reduce pressing bubbles and voids, the outer layer is subjected to wire drawing treatment.

[0034] Specifically, the first and second aluminum plates undergo drilling, resin plugging, inner layering, inner layer AOI, OPE punching, and wire drawing processes. When drilling for resin plugging, the holes are made as large as possible without affecting product quality; the hole size limit is set to 100mm, halved from normal drilling parameters, and coated aluminum sheets and white backing plates are stacked sequentially on the upper and lower surfaces to prevent burrs during drilling; during resin plugging, high-temperature adhesive is applied to one side of the first / second aluminum plate, while the other side is used for resin plugging; a corrosion-resistant layer is applied to the inner layer of the first and second aluminum plates, etching out the rivet hole locations; and a wire drawing process is applied to the outer layers of the first and second aluminum plates to increase the adhesion between the aluminum plate and the PP layer.

[0035] Step S4: Stack the first aluminum plate and the second aluminum plate on the first insulating layer and the second insulating layer respectively, and rivet the first aluminum plate, the first circuit layer and the second aluminum plate together with rivets.

[0036] Step S5: A third insulating layer and a fourth insulating layer are stacked on the outer sides of the first aluminum plate and the second aluminum plate, respectively, and a first copper foil layer and a second copper foil layer are stacked on the other side of the third insulating layer and the fourth insulating layer, wherein the third insulating layer and the fourth insulating layer are PP material layers.

[0037] Step S6: The multilayer board from step S5 is sequentially subjected to lamination, edge routing, drilling, edge wrapping, copper plating, adhesive removal, electroplating, and circuit processing, so that the first copper foil layer forms the second circuit layer, the second copper foil layer forms the third circuit layer, and the second circuit layer is subjected to solder resist and text printing processes.

[0038] Specifically, during a single pressing, the layers are stacked in the following order: steel plate / buffer pad / multilayer board / buffer pad / steel plate. The buffer pad consists of a first PET layer 201, a PE / PO layer 202, and a second PET layer 203 stacked sequentially, as shown in the diagram. Figure 1 As shown, the buffer pad uses a three-in-one design, serving functions such as filling differences in height, uniform pressure, release, and adhesive resistance. This results in more uniform adhesive flow and better board thickness consistency after lamination. The PE / PO layer's flow temperature is near the lowest viscosity value of most PP layers. This flowing pressure-transmitting medium layer ensures true hydrostatic pressure for the laminated product, which is beneficial for resin fillers, especially those with low flow rates. It also effectively controls expansion and contraction, leading to greater dimensional stability in multilayer boards.

[0039] In the drilling process, the drilling limit is set to 100, which is half of the normal drilling parameters. The coated aluminum sheet and white backing plate are also stacked on the upper and lower surfaces in sequence to avoid burrs during drilling. The edges of the board are wrapped with red tape to enhance the mechanical strength of the circuit board, prevent electromagnetic radiation, improve anti-interference ability and extend service life.

[0040] After the copper plating process, the first, second, and third circuit layers can achieve conductive connection.

[0041] Step S7: Take the third aluminum plate and brush one side of its surface. The brushed side of the third aluminum plate is then bonded and fixed to the third circuit layer.

[0042] The third aluminum plate is bonded to the third circuit layer with reinforcing adhesive, and the wire drawing process is used to enhance the bonding strength between the third aluminum plate and the reinforcing adhesive; while the surface of the second circuit layer is coated with high-temperature adhesive and undergoes browning treatment to ensure the performance and lifespan of the product in high-temperature environments.

[0043] Step S8: Perform a second pressing and screen print blue adhesive on the other side of the third aluminum plate;

[0044] During the secondary lamination process, release films are applied to the upper and lower surfaces of the multilayer board to prevent the circuit board from becoming dirty.

[0045] Step S9: Surface treatment and molding to obtain a multilayer aluminum substrate.

[0046] It should be noted that the third aluminum plate can also be bonded and fixed to the second circuit layer with reinforcing adhesive. Correspondingly, the third circuit layer undergoes solder resist, text printing, and browning treatment processes.

[0047] Please see Figure 2 This is a schematic diagram of the structure of a multilayer aluminum substrate obtained by the fabrication method of the multilayer aluminum substrate of the present invention. The multilayer aluminum substrate includes:

[0048] A first circuit layer 1, a first insulating layer 2 and a second insulating layer 3 stacked on both sides of the first circuit layer 1, a first aluminum plate 4 and a second aluminum plate 5 stacked on the surfaces of the first insulating layer 2 and the second insulating layer 3 respectively, a third insulating layer 6 and a fourth insulating layer 7 stacked on the surfaces of the first aluminum plate 4 and the second aluminum plate 5 respectively, a second circuit layer 8 and a third circuit layer 9 stacked on the surfaces of the third insulating layer 6 and the fourth insulating layer 7 respectively, and a third aluminum plate 10 bonded and fixed to the third circuit layer 9, thereby forming an adhesive layer 11 between the third circuit layer 9 and the third aluminum plate 10, and the adhesive layer 11 is formed by reinforcing adhesive.

[0049] The thickness of the first insulating layer 2, the second insulating layer 3, the third insulating layer 6, and the fourth insulating layer 7 is 0.1 to 0.15 mm, or 0.1 mm, and they are made of PP material. The thickness of the first aluminum plate 4, the second aluminum plate 5, and the third aluminum plate 10 is determined according to the finished plate thickness.

[0050] The first circuit layer 1, the first aluminum plate 4, and the second aluminum plate 5 are riveted together, and the first aluminum plate 4 and the second aluminum plate 5 include resin plug holes 12.

[0051] In this invention, after the first circuit layer 1, the first insulating layer 2, the second insulating layer 3, the first aluminum plate 4, the second aluminum plate 5, the third insulating layer 6, the fourth insulating layer 7, the second circuit layer 8, and the third circuit layer 9 are stacked in sequence, copper plating holes 13 are formed on the multilayer board through lamination, drilling, and copper plating processes. The copper plating holes connect the first circuit layer, the second circuit layer, and the third circuit layer, realizing the conductive connection between the outer layer circuit and the inner layer circuit.

[0052] The method for manufacturing a multilayer aluminum substrate provided by this invention can also add an insulating layer, an aluminum plate, an insulating layer, and a circuit layer on the outer circuit as needed, thereby further increasing the wiring space of the circuit board.

[0053] The method for manufacturing a multilayer aluminum substrate provided by this invention increases the number of aluminum substrate layers (serving as heat dissipation layers) and the number of circuit layers, providing more wiring space and making it suitable for complex circuit designs.

[0054] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a multilayer aluminum substrate, characterized in that, Includes the following steps: Step S1: Take the inner core board, fabricate the inner layer circuitry, and form the first circuit layer; Step S2: Stack the first insulating layer and the second insulating layer on both sides of the first circuit layer, respectively. Step S3: Provide a first aluminum plate and a second aluminum plate, drill holes using a drilling coefficient that is consistent with the expansion and contraction coefficient of the inner core board, plug the holes with resin after drilling, and make rivet holes in the inner layer of the first aluminum plate and the second aluminum plate, and perform wire drawing on the outer layer. Step S4: Stack the first aluminum plate and the second aluminum plate on the first insulating layer and the second insulating layer respectively, and rivet the first aluminum plate, the first circuit layer and the second aluminum plate together with rivets. Step S5: A third insulating layer and a fourth insulating layer are stacked on the outer sides of the first aluminum plate and the second aluminum plate, respectively, and a first copper foil layer and a second copper foil layer are stacked on the other side of the third insulating layer and the fourth insulating layer, respectively. Step S6: The multilayer board from step S5 is sequentially laminated, routerd, drilled, copper plated, electroplated, and processed with circuitry to form the second circuitry layer from the first copper foil layer and the third circuitry layer from the second copper foil layer. Solder resist and text printing processes are then applied to the second circuitry layer. Step S7: Take the third aluminum plate and brush one side of its surface. The brushed side of the third aluminum plate is then bonded and fixed to the third circuit layer. Step S8: Perform a second pressing and screen print blue adhesive on the other side of the third aluminum plate; Step S9: Surface treatment and molding to obtain a multilayer aluminum substrate.

2. The method for manufacturing a multilayer aluminum substrate according to claim 1, characterized in that, In step S1, the bottom copper on one side of the inner core board is etched away, and the inner circuitry is made on the other side to form the first circuit layer.

3. The method for manufacturing a multilayer aluminum substrate according to claim 1, characterized in that, The first, second, third, and fourth insulating layers are made of PP material.

4. The method for manufacturing a multilayer aluminum substrate according to claim 1, characterized in that, In step S6, during the first pressing, the plates are stacked in the order of steel plate / buffer pad / multilayer board / buffer pad / steel plate, wherein the buffer pad includes a first PET layer, a PE / PO layer and a second PET layer stacked in sequence.

5. The method for manufacturing a multilayer aluminum substrate according to claim 1, characterized in that, Before the second lamination, the surface of the second circuit layer is treated with high-temperature adhesive and browning.

6. The method for manufacturing a multilayer aluminum substrate according to claim 1, characterized in that, In step S8, during the secondary pressing, release films are applied to the upper and lower surfaces of the multilayer board.

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