CN112930024B

CN112930024B - Metal-based circuit board and manufacturing method thereof

Info

Publication number: CN112930024B
Application number: CN202110095992.0A
Authority: CN
Inventors: 刘玮; 刘晨; 雷振南
Original assignee: Kinwong Electronic Technology Longchuan Co Ltd
Current assignee: Kinwong Electronic Technology Longchuan Co Ltd
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2022-05-03
Anticipated expiration: 2041-01-25
Also published as: CN112930024A

Abstract

The invention is suitable for the field of circuit board manufacturing, and provides a metal-based circuit board and a manufacturing method thereof, wherein the manufacturing method of the metal-based circuit board comprises the following steps: providing a substrate, a first dielectric layer and a conducting layer, wherein the substrate is a metal composite plate and comprises an aluminum layer and a copper layer pressed on the aluminum layer; sequentially laminating and pressing the substrate, the first dielectric layer and the conductive layer into a plate, wherein the copper layer is attached to the first dielectric layer; a connecting hole is formed in the plate and at least penetrates through the conducting layer and the first medium layer; and manufacturing a circuit layer by using the conductive layer to form the metal-based circuit board. The manufacturing method of the metal-based circuit board can manufacture the metal-based circuit board with the grounding function, and is low in cost and good in product reliability and safety.

Description

Metal-based circuit board and manufacturing method thereof

Technical Field

The invention relates to the technical field of circuit board manufacturing, in particular to a metal-based circuit board and a manufacturing method thereof.

Background

The conventional aluminum-based circuit board comprises a single-sided aluminum-based circuit board, a double-sided sandwich aluminum-based circuit board and a single-sided multilayer aluminum-based circuit board, wherein the single-sided aluminum-based circuit board is generally designed without a through hole, and the double-sided sandwich aluminum-based circuit board or the single-sided multilayer aluminum-based circuit board is generally provided with a through hole.

When the product is designed in a complex way and needs to be connected with the circuit layer and the aluminum base in a conduction way, if a conventional electroplating mode is adopted, the aluminum base is easily corroded by the liquid medicine during electroplating, so that the electroplating liquid medicine is polluted; the front-edge aluminum-based electroplating process has high cost, immature technology and risk on product reliability. Therefore, blind holes are drilled from the circuit layer to the aluminum base, and then conductive media (such as copper paste, silver paste and carbon ink) are printed by silk screen to realize the conduction between the circuit layer and the aluminum base; however, when the circuit board is subjected to REFLOW (IR REFLOW), cracking is likely to occur due to the difference in the coefficient of expansion between the conductive medium and the aluminum base, the on-resistance increases, and even conduction failure may occur.

Disclosure of Invention

In view of the above, the present invention provides a metal-based circuit board and a method for manufacturing the same to solve the above problems.

The embodiment of the invention provides a manufacturing method of a metal-based circuit board, which comprises the following steps:

providing a substrate, a first dielectric layer and a conducting layer, wherein the substrate is a metal composite plate and comprises an aluminum layer and a copper layer pressed on the aluminum layer;

sequentially laminating and pressing the substrate, the first dielectric layer and the conductive layer into a plate, wherein the copper layer is attached to the first dielectric layer;

a connecting hole is formed in the plate and at least penetrates through the conducting layer and the first medium layer;

and manufacturing a circuit layer by using the conductive layer to form the metal-based circuit board.

In an embodiment, before the substrate, the first dielectric layer, and the conductive layer are sequentially stacked and pressed into a board, the manufacturing method further includes:

providing a protection frame, wherein the middle part of the protection frame is provided with an embedded groove;

and nesting the substrate in the embedding groove, and pressing the protection frame and the substrate, wherein the protection frame covers the side wall of the substrate.

In one embodiment, the protection frame is an FR4 outer frame and the thickness of the protection frame matches the thickness of the substrate;

the side wall of the protection frame is convexly provided with a clamping part, the periphery of the base plate is concavely provided with a clamping groove, and the clamping part of the protection frame is clamped in the corresponding clamping groove.

In an embodiment, the engaging groove is a T-shaped groove and includes a first groove and a second groove that are communicated with each other, the first groove is located at an edge of the substrate, a length of the first groove is greater than a length of the second groove, depths of the first groove and the second groove are both 6mm to 10mm, widths of the first groove and the second groove are both 3mm to 5mm, and a length of the first groove is 7mm to 10 mm.

In one embodiment, the plate further comprises a protective copper layer;

and during lamination, the protective copper layer is laminated on one side of the substrate, which is far away from the first dielectric layer.

In one embodiment, the plate further comprises a high-temperature resistant protective film and a second dielectric layer;

and during lamination, the high-temperature-resistant protective film, the second dielectric layer and the protective copper layer are sequentially stacked on one side of the substrate, which is far away from the first dielectric layer.

In one embodiment, the protective copper layer is etched away when the circuit layer is manufactured;

after the circuit layer is manufactured, the manufacturing method further comprises the following steps:

routing the shape of the metal-based circuit board through a routing board;

and tearing off the high-temperature-resistant protective film and the second medium layer.

In one embodiment, the connecting hole is formed in the plate by a depth control drilling or laser drilling method.

In an embodiment, after the plate is provided with the connection hole, the manufacturing method further includes: and filling a conductive material in the connecting hole in a mode of electroplating or screen printing of solder paste.

The embodiment of the invention also provides a metal-based circuit board which is manufactured by adopting the manufacturing method in any one of the above embodiments.

The manufacturing method of the metal-based circuit board adopts the composite metal plate comprising the copper layer and the aluminum layer as the substrate, and the copper layer is arranged on one side of the aluminum layer close to the conductive layer, namely the copper layer is positioned on the upper side of the aluminum layer, so that the aluminum layer can not contact with liquid medicine during electroplating, and the pollution of the liquid medicine is avoided; copper can be deposited on the hole wall of the connecting hole through electroplating, so that the circuit layer is conducted with the copper layer of the composite metal plate, the circuit layer and the aluminum layer are finally conducted, the reliability of the metal-based circuit board is good, and the problem of grounding failure can be avoided. In addition, the manufacturing method of the metal-based circuit board can be matched with a conventional electroplating process, an additional new production line is not needed, the universality is good, and the production cost is saved. Therefore, the manufacturing method of the metal-based circuit board can manufacture the metal-based circuit board with the grounding function, and has the advantages of low cost and good reliability and safety of products.

The circuit layer of the metal-based circuit board can be conducted with the aluminum layer of the substrate, so that the grounding function can be realized in a use environment, the safety of the product is improved, and the additional value of the product is increased; and the metal-based circuit board is manufactured by the manufacturing method, so that the cost is low.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a flowchart of a method for manufacturing a metal-based circuit board according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a plate member according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a metal-based circuit board according to an embodiment of the present invention;

fig. 4 is a flowchart of a method for manufacturing a metal-based circuit board according to another embodiment of the present invention.

FIG. 5 is a schematic structural diagram of a protective frame and a substrate according to another embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a plate member according to yet another embodiment of the present invention;

fig. 7 is a schematic structural diagram of a metal-based circuit board according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a metal-based wiring board according to another embodiment of the present invention.

The designations in the figures mean:

100. a metal-based circuit board; 200. a plate member; 10. a substrate; 11. an aluminum layer; 12. a copper layer; 13. a clamping groove; 131. a first groove; 132. a second groove; 20. a first dielectric layer; 30. a conductive layer; 30', a circuit layer; 40. a protective frame; 41. embedding a groove; 50. protecting the copper layer; 60. a high temperature resistant protective film; 70. a second dielectric layer; 101. and connecting the holes.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, which are examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly or indirectly secured to the other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element. The terms "upper", "lower", "left", "right", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, are not to be construed as limiting the patent. The terms "first", "second" and "first" are used merely for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "plurality" is two or more unless specifically limited otherwise.

To illustrate the technical solution of the present invention, the following description is made with reference to the specific drawings and examples.

The embodiment of the invention provides a manufacturing method of a metal-based circuit board, which is used for manufacturing the metal-based circuit board with a grounding function.

Referring to fig. 1, a method for manufacturing a metal-based circuit board according to an embodiment of the present invention includes the following steps.

Step S1: a substrate, a first dielectric layer and a conductive layer are provided.

Referring to fig. 2, the substrate 10 is a metal composite plate and includes an aluminum layer 11 and a copper layer 12 laminated on the aluminum layer 11. In one embodiment, the copper content of the substrate 10 is 15% and the aluminum content is 85%, at this time, the material cost of the substrate 10 is low; it will be appreciated that the copper and aluminium contents may be adjusted as desired, for example, the copper content may be between 5% and 50% and the aluminium content between 50% and 95%.

In one embodiment, the first dielectric layer 20 is a PP (pre, epoxy) layer, and the conductive layer 30 is a copper foil.

Step S2: the substrate 10, the first dielectric layer 20 and the conductive layer 30 are sequentially stacked and pressed into the board 200.

As shown in fig. 2, the copper layer 12 is attached to the first dielectric layer 20.

Step S3: a connection hole is formed in the plate 200, and the connection hole penetrates through at least the conductive layer 30 and the first dielectric layer 20.

Referring to fig. 3, the connection hole 101 is a via hole between the conductive layer 30 and the substrate 10, and therefore, the copper layer 12 is exposed from the connection hole 101. In one embodiment, the connection hole 101 penetrates through the conductive layer 30 and the first dielectric layer 20, and exposes the copper layer 12. It is understood that the via 101 may also extend through the conductive layer 30, the first dielectric layer 20, and a portion of the copper layer 12.

Step S4: the conductive layer 30 is used to form a circuit layer 30', and a metal-based wiring board 100 is formed.

The manufacturing method of the metal-based circuit board adopts the composite metal plate comprising the copper layer 12 and the aluminum layer 11 as the substrate 10, and the copper layer 12 is arranged on one side of the aluminum layer 11 close to the conductive layer 30, so that the aluminum layer 11 is positioned below the copper layer 12 during electroplating and cannot contact with liquid medicine, thereby avoiding liquid medicine pollution; in addition, the circuit layer 30 'is conducted with the copper layer 12 through the conductive material in the connection hole 101, so that the circuit layer 30' is conducted with the aluminum layer 11, the reliability of the metal-based circuit board 100 is good, and the problem of grounding failure can be avoided. In addition, the manufacturing method of the metal-based circuit board 100 can be matched with a conventional electroplating process, an additional new production line is not needed, the universality is good, and the production cost is saved. Therefore, the method for manufacturing the metal-based circuit board 100 can manufacture the metal-based circuit board 100 with the grounding function, and has the advantages of low cost, and good reliability and safety of the product.

In an embodiment, after the step S3 of forming the connection hole on the plate, the method further includes: the connection hole 101 is filled with a conductive material by electroplating or screen printing a solder paste.

Referring to fig. 4, another embodiment of the present application provides a method for manufacturing a metal-based circuit board. Compared to the foregoing embodiments, in the present embodiment, before sequentially stacking and laminating the substrate 10, the first dielectric layer 20, and the conductive layer 30 into the board 200, the manufacturing method further includes the following steps.

Step S11: a protective frame is provided, and an embedding groove is formed in the middle of the protective frame.

Referring to fig. 5, the protection frame 40 is a rectangular hollow frame, and an insertion groove 41 is formed in the middle of the protection frame 40, and the insertion groove 41 is a through groove.

Optionally, the protective frame 40 is an FR4 outer frame and the thickness of the protective frame 40 matches the thickness of the substrate 10. For example, the thickness of the FR4 outer frame can be the same or about the same as the thickness of the substrate 10.

In one embodiment, the method for manufacturing the protective frame 40 includes the following steps: cutting according to the size of the substrate 10, wherein the size of the protection frame 40 is 20mm larger than that of the substrate 10; etching off the copper sheets on the two sides of the protective frame 40; drilling a positioning hole; the protection frame 40 is routed out of the embedding groove 41, so that the protection frame 40 is a hollow frame body, the width of one side of the protection frame 40 is 10mm, and the embedding groove 41 is used for placing the substrate 10.

Step S12: the substrate 10 is nested in the embedding groove 41, and the protection frame 40 and the substrate 10 are pressed together.

The protection frame 40 covers the sidewall of the substrate 10.

In one embodiment, the distance between the protection frame 40 and the sidewall of the substrate 10 is 0-0.15 mm.

In the above manufacturing method, the protection frame 40 is used to protect the sidewall of the substrate 10, prevent the sidewall of the substrate 10 from being corroded by the plating solution, and prevent the solution from being contaminated.

As shown in fig. 5, the side wall of the protection frame 40 is provided with a convex holding portion, the periphery of the substrate 10 is provided with a concave engaging groove 13, and the holding portion of the protection frame 40 is held in the corresponding engaging groove 13 to improve the bonding strength between the protection frame 40 and the substrate 10. Alternatively, the substrate 10 is provided with one engaging groove 13 on the periphery thereof.

In an embodiment, the engaging groove 13 is a T-shaped groove and includes a first groove 131 and a second groove 132 that are communicated with each other, the first groove 131 is located at an edge of the substrate 10, a length of the first groove 131 is greater than a length of the second groove 132, depths of the first groove 131 and the second groove 132 are both 6mm to 10mm, widths of the first groove 131 and the second groove 132 are both 3mm to 5mm, and a length of the first groove 131 is 7mm to 10 mm.

Since the engaging groove 13 is a T-shaped groove, the bonding force between the protective frame 40 and the substrate 10 is increased, and the gap between the substrate 10 and the protective frame 40 in the subsequent process is prevented from being increased, so that the protective effect of the protective frame 40 is not affected.

Accordingly, in preparing the substrate 10, the sub-process is as follows: cutting the substrate 10 into a designed size; drilling a positioning hole on the substrate 10; routing a clamping groove 13 on the substrate 10; grinding the copper layer 12 to remove an oxide layer on the copper surface; browning, which is to brown the surface of the copper layer 12 and the side wall of the copper layer 12, so as to improve the bonding force between the copper layer 12 and the first dielectric layer 20 during subsequent pressing and improve the bonding force between the copper layer 12 and the protective frame 40.

Referring to fig. 6, in another embodiment of the present invention, the protection frame 40 is located on the periphery of the substrate 10.

The board 200 further includes a protective copper layer 50; during lamination, the protective copper layer 50 is stacked on the substrate 10 at a side away from the first dielectric layer 20. Because both sides of base plate 10 all are equipped with the copper layer, when electroplating, electroplating current can evenly distributed, has promoted the homogeneity of electroplating.

Further, during lamination, the plate 200 further includes a high temperature resistant protective film 60 and a second dielectric layer 70; the high-temperature resistant protective film 60 can be a protective film containing a PI material, and the PI material can resist the high temperature of 250 ℃; the second dielectric layer 70 may be a PP layer.

During lamination, the first dielectric layer 20 and the conductive layer 30 are sequentially stacked on the side of the substrate 10 having the copper layer 12, and the high temperature resistant protective film 60, the second dielectric layer 70 and the protective copper layer 50 are sequentially stacked on the side of the substrate 10 away from the first dielectric layer 20.

In this embodiment, the high temperature resistant protective film 60 is added on the aluminum layer 11 side of the substrate 10, and first, the high temperature resistant protective film 60 can protect the aluminum surface; secondly, the high temperature resistant protective film 60 is provided to facilitate the peeling of the second dielectric layer 70 from the aluminum layer 11. In addition, since the high temperature resistant protective film 60 cannot be tightly bonded to the protective copper layer 50, a second dielectric layer 70 is added between the high temperature resistant protective film 60 and the protective copper layer 50.

It can be understood that, if the aluminum layer 11 is directly laminated with the second dielectric layer 70, the laminated second dielectric layer 70 is difficult to remove, and if the plate is ground by using an abrasive belt, the aluminum layer 11 is worn, and the thickness of the aluminum plate is uneven; if the second dielectric layer 70 remains on the surface of the aluminum layer 11, the heat dissipation of the aluminum layer 11 is affected. Therefore, the high-temperature-resistant protective film 60 is adhered to the surface of the aluminum layer 11 before lamination, so that the aluminum layer 11 can be protected, and the second dielectric layer 70 and the aluminum layer 11 can be isolated by the high-temperature-resistant protective film 60 during lamination.

In one embodiment, the protective copper layer 50 is etched away during the fabrication of the circuit layer; after the circuit layer 30' is manufactured, the manufacturing method further includes: routing the shape of the metal base circuit board 100 by routing; and tearing off the high-temperature resistant protective film 60 and the second medium layer 70.

After the board is milled, the second dielectric layer 70 can be taken away by tearing off the high temperature resistant protective film 60, the manufacturing process is simple and convenient, and the substrate 10 is not damaged.

In one embodiment, a connecting hole 101 is formed in the plate 200 by a depth control drilling method; the connection hole 101 is filled with a conductive material by electroplating or screen printing a solder paste.

For example, a depth control drill is first used to control the depth to the copper layer 12, and a through hole is drilled in the depth control hole and penetrates through the aluminum layer 11, wherein the aperture of the depth control hole is larger than the aperture of the through hole by more than 0.2 mm. At this time, when the metal-based circuit board is mounted, the circuit layer 30 'and the copper layer 12 of the substrate 10 may be electrically connected to each other by using a ladder steel mesh and using solder paste, thereby achieving grounding of the circuit layer 30'. Or, the through hole can be drilled firstly, and then the depth control drill is adopted, so that the method is also suitable for sticking the parts.

As shown in fig. 7, the connection hole 101 of the metal-based wiring board 100 is filled with a conductive material, and the wiring layer 30' is electrically connected to the copper layer 12 and the aluminum layer 11.

As shown in fig. 8, in another embodiment, a connection hole 101 is formed by a laser drilling method; the aperture of the connection hole 101 is 0.075mm to 0.175 mm. After laser drilling, the connection hole 101 is filled with a conductive material.

The following illustrates a method of manufacturing the metal-based wiring board 100.

First, a substrate 10, a protective frame 40, a first dielectric layer 20, a conductive layer 30, a high temperature resistant protective film 60, a second dielectric layer 70, and a protective copper layer 50 are provided, and stacked with reference to the structure shown in fig. 6, and the layers are laminated to form a board 200. Then, drilling a positioning hole on the protective frame, and milling off the redundant waste material at the edge of the plate, for example, milling off 3mm at one side.

Then, drilling a connecting hole 101 in a laser drilling mode or a depth control drilling mode to expose the copper layer 12 of the substrate 10; and (4) adopting a conventional electroplating mode to electroplate and fill the hole, so that the connecting hole is filled with the conductive material.

Then, a circuit layer 30' is manufactured, and the protective copper layer 50 is etched away to expose the second dielectric layer 70; manufacturing a solder mask and drilling a positioning hole; then routing the board, and routing the product according to the shape of the shipment; and tearing off the high-temperature resistant protective film, and simultaneously stripping the second medium layer 70.

And then, grinding the plate to grind off an oxide layer of the aluminum layer, carrying out open-short circuit test and surface treatment, forming an anti-oxidation layer on the online pavement, and then inspecting and packaging.

The invention also provides a metal-based circuit board 100 which is manufactured by adopting the manufacturing method of any one of the above embodiments.

The circuit layer 30' of the metal-based circuit board 100 can be conducted with the aluminum layer 11 of the substrate 10, so that the grounding function can be realized in a use environment, the safety of the product is improved, and the additional value of the product is increased; moreover, the metal-based circuit board 100 is manufactured by the manufacturing method, so that the cost is low.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.

Claims

1. A method for manufacturing a metal-based circuit board is characterized by comprising the following steps:

providing a substrate, a first dielectric layer, a conductive layer, a protective copper layer, a high-temperature-resistant protective film and a second dielectric layer, wherein the substrate is a metal composite plate and comprises an aluminum layer and a copper layer pressed on the aluminum layer;

sequentially laminating the substrate, the first dielectric layer and the conductive layer, and sequentially laminating the high-temperature-resistant protective film, the second dielectric layer and the protective copper layer on one side of the substrate, which is far away from the first dielectric layer, and pressing the two layers into a plate, wherein the copper layer is attached to the first dielectric layer;

manufacturing a circuit layer by using the conductive layer, and etching off the protective copper layer;

routing the shape of the metal-based circuit board through a routing board;

and tearing off the high-temperature-resistant protective film and the second dielectric layer to form the metal-based circuit board.

2. The method of manufacturing a metal-based wiring board according to claim 1, wherein before the substrate, the first dielectric layer, and the conductive layer are sequentially stacked and laminated into a board, the method further comprises:

3. The method for manufacturing a metal-based circuit board according to claim 2, wherein the protective frame is an FR4 outer frame and the thickness of the protective frame matches with the thickness of the substrate;

4. The method for manufacturing a metal-based circuit board according to claim 3, wherein the engaging groove is a T-shaped groove and includes a first groove and a second groove that are communicated with each other, the first groove is located at an edge of the substrate, the length of the first groove is greater than that of the second groove, the depths of the first groove and the second groove are both 6mm to 10mm, the widths of the first groove and the second groove are both 3mm to 5mm, and the length of the first groove is 7mm to 10 mm.

5. The method of claim 1, wherein the connecting holes are formed in the board by depth-controlled drilling or laser drilling.

6. The method of manufacturing a metal-based wiring board according to claim 1, wherein after the board is provided with the connection hole, the method further comprises:

and filling a conductive material in the connecting hole in a mode of electroplating or screen printing of solder paste.

7. A metal-based wiring board produced by the production method according to any one of claims 1 to 6.