Packaging substrate and manufacturing method thereof

Abstract

The present invention discloses a packaging substrate and a method for manufacturing the same. The packaging substrate includes a metal substrate and a circuit substrate provided with a conductive structure. The metal substrate and the circuit substrate are bonded together by an adhesive sheet. The circuit substrate is provided with multiple through-holes, and the metal substrate has multiple metal bosses disposed within the through-holes. The metal substrate is provided with a grid-shaped insulating groove that penetrates the metal substrate and is filled with a resin material. Each grid of the insulating groove forms a metal heat-conducting unit, and multiple metal bosses are correspondingly disposed on the multiple metal heat-conducting units. Insulating holes are provided at positions corresponding to the grid nodes of the insulating groove in the packaging substrate to achieve electrical insulation between the multiple metal heat-conducting units. The packaging substrate of the present invention not only achieves a dense distribution of the metal heat-conducting units, but also has excellent heat dissipation performance.

Description

Technical Field

[0001] The present invention relates to the field of packaging substrates; more specifically, to a packaging substrate capable of achieving dense distribution of metal heat conduction units and a manufacturing method thereof. Background Art

[0002] Electronic components such as LEDs (light-emitting diodes) generate a lot of heat when in operation, so their packaging substrates must have good thermal conductivity. To improve thermal conductivity, thermally conductive components such as ceramic blocks or copper blocks can be embedded in the packaging substrate.

[0003] In the prior art, a conventional packaging substrate structure includes multiple stacked insulating core boards, with thermal conductors embedded in the through holes of the insulating core boards. When manufacturing the packaging substrate, semi-cured sheets are set between the insulating core boards for pressing. During the pressing process, the semi-cured sheets flow and fill into the through holes of the insulating core boards to fix the thermal conductors.

[0004] In some applications, the heating elements on the package substrate are densely distributed. The thermal conductors used are small in size and large in number, and the thermal conductivity requirements are high. It is difficult to meet the requirements using conventional thermal conductor embedding structures and methods. Summary of the Invention

[0005] To at least partially solve the problems of the prior art, a first aspect of the present invention provides a method for manufacturing a package substrate, comprising the following steps:

[0006] S1, processing a plurality of metal bosses on at least one surface of a metal substrate;

[0007] S2, machining a grid-shaped insulating groove penetrating the metal substrate in the metal substrate; wherein the grid nodes of the insulating groove form a connecting bridge, each grid of the insulating groove forms a metal heat conducting unit inside, and the plurality of metal bosses are correspondingly arranged on the plurality of metal heat conducting units;

[0008] S3, machining through holes at positions corresponding to the metal bosses on the prepreg bonding sheet and the circuit substrate having at least an outer copper foil layer;

[0009] S4, pressing the prepreg and the circuit substrate together on the surface of the metal substrate provided with the metal boss, and simultaneously filling the insulating groove with a resin material during the pressing process;

[0010] S5, removing the resin material on both sides of the packaging substrate obtained in step S4;

[0011] S6, performing copper plating on the entire surface of the packaging substrate provided with the metal bosses to form a copper cladding layer connecting and covering the metal bosses and the outer copper foil;

[0012] S7, performing patterned etching on the copper cladding layer and the outer copper foil;

[0013] S8, drilling insulating holes on the packaging substrate at positions corresponding to the connection bridges to remove the connection bridges and achieve electrical insulation between the plurality of metal heat-conducting units.

[0014] In the manufacturing method of the present invention, metal bosses and a grid-like insulating groove are first machined onto a metal substrate. Each grid has a metal heat-conducting unit within it, allowing for a densely distributed arrangement of multiple metal heat-conducting units. The insulating grooves have a non-enclosed grid structure, with the grid nodes forming connecting bridges to maintain interconnection between the various components of the metal substrate, facilitating subsequent pressing. During the pressing process, the insulating grooves are filled with resin material, and after pressing, insulating holes are drilled to achieve electrical insulation between the multiple metal heat-conducting units, thereby improving the voltage resistance of the package substrate. The metal bosses on the metal heat-conducting units are used to connect to heating elements. Heat generated by the heating elements can be rapidly transferred through the metal heat-conducting units, resulting in the package substrate having excellent heat dissipation performance.

[0015] According to a specific embodiment of the present invention, step S1 processes the metal boss on the first surface of the metal substrate, and step S4 presses the semi-cured filling sheet on the second surface of the metal substrate relative to the first surface while pressing the semi-cured adhesive sheet and the circuit substrate.

[0016] Furthermore, the resin content of the prepreg filling sheet is higher than that of the prepreg bonding sheet. Using the prepreg bonding sheet and the prepreg filling sheet with higher resin content and fluidity to fill the insulation slot with resin is beneficial to improving the filling degree of the resin material in the insulation slot.

[0017] Furthermore, in step S4, the semi-cured filling sheet is stacked on top of the metal substrate, and the semi-cured bonding sheet and the circuit substrate are stacked below the metal substrate, so as to promote the resin material in the semi-cured filling sheet to flow into the insulating groove during the pressing process.

[0018] According to another specific embodiment of the present invention, step S1 processes a plurality of metal bosses on the first surface of the metal substrate and the second surface relative to the first surface; step S4 simultaneously presses the semi-cured adhesive sheet and the circuit substrate on the first surface and the second surface of the metal substrate.

[0019] Optionally, the circuit substrate is a double-sided circuit substrate having an inner copper foil and an outer copper foil; before step S4 of laminating the semi-cured adhesive sheet and the circuit substrate, a conductive circuit is first processed in the inner copper foil.

[0020] Optionally, step S1 is to obtain the metal boss by partially etching the metal substrate.

[0021] Optionally, in step S2 , the metal substrate is laser cut to obtain the insulating groove, and the width of the insulating groove is 0.2 mm to 0.5 mm.

[0022] Optionally, the metal substrate is a copper substrate.

[0023] In order to at least partially solve the problems of the prior art, the second aspect of the present invention discloses a packaging substrate, comprising a metal substrate and a circuit substrate provided with a conductive structure, wherein the metal substrate and the circuit substrate are bonded together by a semi-cured adhesive sheet, the circuit substrate is provided with a plurality of through holes, and the metal substrate has a plurality of metal bosses arranged in the through holes; wherein, a grid-shaped insulating groove passing through the metal substrate is provided in the metal substrate, and the insulating groove is filled with resin material; a metal heat-conducting unit is formed inside each grid of the insulating groove, and a plurality of the metal bosses are correspondingly arranged on the plurality of the metal heat-conducting units; insulating holes are provided at positions corresponding to the grid nodes of the insulating groove in the packaging substrate to achieve electrical insulation between the plurality of the metal heat-conducting units.

[0024] According to a specific implementation of the second aspect of the present invention, the metal substrate is a copper substrate; and the width of the insulating groove is 0.2 mm to 0.5 mm.

[0025] In the packaging substrate of the present invention, the metal substrate is provided with a grid of insulating grooves filled with a resin material. Insulating holes are provided at the grid nodes of the insulating grooves, forming a plurality of densely distributed and electrically insulated metal heat-conducting units. The metal bosses on the metal heat-conducting units are used to connect to the heating element. Heat generated by the heating element is rapidly transferred through the metal heat-conducting units, resulting in the packaging substrate having excellent heat dissipation performance.

[0026] In order to more clearly illustrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is an exemplary flow chart of the production method of the present invention;

[0028] Figure 2 This is a schematic diagram of the front structure of the metal substrate after the bosses and insulation grooves are processed in Example 1;

[0029] Figure 3 yes Figure 2 AA section view;

[0030] Figure 41 is a schematic diagram of the stacked structure when the package substrates are pressed together in Example 1;

[0031] Figure 5 is a schematic structural diagram of the package substrate after lamination in Example 1;

[0032] Figure 6 This is a schematic diagram of the structure of the package substrate after copper plating in Example 1;

[0033] Figure 7 This is a structural diagram of drilling insulating holes at positions corresponding to the connecting bridges in Example 1;

[0034] Figure 8 It is a schematic diagram of the structure of the packaging substrate after pressing in Example 2. DETAILED DESCRIPTION

[0035] In the following description, many specific details are set forth in conjunction with specific embodiments to facilitate a full understanding of the present invention. However, it should be understood that the following embodiments and detailed descriptions are only for illustrative purposes and do not limit the scope of protection of the present invention.

[0036] Example 1

[0037] Figure 1 This is an exemplary flow chart of some steps in an embodiment of the manufacturing method of the present invention. In this exemplary flow chart, some steps that are the same as those in the prior art are omitted except for the steps shown in the figure.

[0038] refer to Figure 1 As shown, the packaging substrate manufacturing method of the embodiment includes step S1 of processing a plurality of metal bosses on at least one surface of a metal substrate; wherein the metal substrate is preferably a copper substrate, and may also be an aluminum substrate or an aluminum-copper composite substrate.

[0039] In Example 1, Figure 2 and Figure 3 As shown, a metal substrate 10 has a first surface 10a and a second surface 10b disposed opposite each other. In step S1, a plurality of metal bosses 12 are machined on the first surface 10a of the metal substrate 10. The plurality of metal bosses 12 can be arranged in a two-dimensional array as shown in the figure, or can be distributed radially. The orthographic projection / cross-sectional shape of the metal bosses 12 can be rectangular or circular, etc. The specific distribution pattern and shape can be determined according to the application requirements and are not limited in the present invention.

[0040] For example, the metal bosses 12 can be formed by partially etching the metal substrate 10. During the partial etching, the thickness of the etched area on the surface of the metal substrate 10 is reduced, and the unetched area forms the metal bosses 12 accordingly. Alternatively, the metal bosses 12 can be formed by partial electroplating, that is, the metal bosses 12 are electroplated at predetermined locations on the metal substrate 10. The present invention does not limit the method for manufacturing the metal bosses 12.

[0041] The packaging substrate manufacturing method of the embodiment also includes step S2 of processing a grid-shaped insulating groove 13 in the metal substrate 10. Step S2 is preferably performed after step S1, but step S2 can also be performed first and then step S1 (for example, when the metal boss 12 is locally electroplated, step S2 can be performed first and then step S1).

[0042] Specifically, such as Figure 2 and Figure 3 As shown, the insulating slots 13 penetrate the metal substrate 10 in the thickness direction and have a non-closed grid structure. The grid nodes form connecting bridges 14, and each grid (grid unit) forms a metal heat-conducting unit 11. This grid-structured insulating slot 13 can achieve a dense distribution of the metal heat-conducting units 11. Multiple metal bosses 12 are correspondingly provided on the multiple metal heat-conducting units 11 and form part of the metal heat-conducting units 11; each metal heat-conducting unit 11 can correspond to one metal boss 12, or can correspond to multiple metal bosses 12. Figure 2 The grid structure of the insulating slot 13 is merely exemplary. The size and shape of each grid unit in the grid structure of the insulating slot 13 may be determined according to the overall size and shape of the metal heat conducting unit 11 , and the present invention does not impose any limitation thereto.

[0043] In the present invention, the insulating groove 13 is preferably obtained by a laser cutting method to obtain an insulating groove 13 of smaller width, thereby increasing the dense distribution of the metal heat-conducting unit 11. Exemplarily, the width of the insulating groove 13 can be 0.2mm to 0.5mm, but is not limited thereto. The function of the connecting bridge 14 is to keep the frame 15 of the metal substrate 10 and the metal heat-conducting unit 11 connected after the insulating groove 13 is made, to maintain the overall integrated structure of the metal substrate 10, so as to facilitate the subsequent pressing step. The size of the connecting bridge 14 (the minimum spacing L between the ends of adjacent insulating grooves 13) can be 0.5mm to 1mm, but is not limited thereto, as long as the various parts of the metal substrate 10 can maintain appropriate connection strength.

[0044] The method for manufacturing a package substrate of the embodiment further includes a step S3 of machining through holes in the semi-cured bonding sheet and the circuit substrate. Specifically, Figure 4As shown, prepreg 21 is machined with through-holes 210 corresponding to metal bosses 12, and circuit substrate 30 is machined with through-holes 310 corresponding to metal bosses 12. Prepreg 21 can be made of a prepreg containing fiberglass cloth, such as FR-4, FR-15, or other prepregs containing fiberglass cloth, but is not limited thereto.

[0045] In this embodiment, the circuit substrate 30 utilizes a single-sided copper-clad core laminate, comprising an insulating core 31 and an outer copper foil 32 disposed on the outer surface of the insulating core 31. The insulating core 31 may be a fiberglass-containing core, such as FR-4, FR-15, or other fiberglass-containing cores, but is not limited thereto. As a variation of this embodiment, the circuit substrate 30 may utilize a double-sided copper-clad core laminate. In addition to the outer copper foil 32, this double-sided copper-clad core laminate also includes an inner copper foil disposed on the inner surface of the insulating core 31. Before the prepreg sheet 21 and circuit substrate 30 are laminated to the metal substrate 10, conductive traces may be fabricated in the inner copper foil.

[0046] In step S4, Figure 4 As shown, a prepreg sheet 21 and a circuit substrate 30 are laminated onto the first surface 10a of the metal substrate 10, which is provided with metal bosses 12. The metal bosses 12 are embedded in the through-holes between the prepreg sheet 21 and the circuit substrate 30. During the lamination process, the resin material in the prepreg sheet 21 flows to fill the gap between the circuit substrate 30 and the metal bosses 12 and then flows into the insulation grooves 13.

[0047] Preferably, Figure 4 As shown, in step S4, when the prepreg bonding sheet 21 and the circuit substrate 30 are pressed together, the prepreg filling sheet 22 is pressed together on the second surface 10b of the metal substrate 10; during the pressing, the resin material in the prepreg filling sheet 22 will also flow into the insulating groove 13, that is, during the pressing, the prepreg bonding sheet 21 and the prepreg filling sheet 22 will both fill the insulating groove 13 with the resin material 20 (see FIG. Figure 5 ).

[0048] The resin content of the prepreg filling sheet 22 is higher than that of the prepreg bonding sheet 21. For example, the prepreg bonding sheet 21 is made of fiberglass cloth, while the prepreg filling sheet 22 is made of non-woven fabric. Compared to fiberglass cloth prepregs, non-woven fabric prepregs have a higher resin content and a loose, short fiber structure, providing a stronger filling capability for the insulation slots 13, ensuring more reliable filling of the insulation slots 13 with the resin material 20. The thickness of the prepreg filling sheet 22 is preferably at least 150 μm, but is not limited thereto.

[0049] Preferably, in step S4, the prepreg filling sheet 22 is stacked on top of the metal substrate 10, and the prepreg bonding sheet 21 and circuit substrate 30 are stacked below the metal substrate 10. This facilitates the flow of the resin material in the prepreg filling sheet 22 to fill the insulating groove 13. The resin material 20 not only enhances the structural strength of the package substrate, but also provides electrical insulation between the metal heat conducting units 11.

[0050] As a variation of the embodiment, the semi-cured adhesive sheet 21 can be a semi-cured sheet with high resin content and high fluidity (such as a non-woven fabric semi-cured sheet), and the semi-cured adhesive sheet 21 and the circuit substrate 30 can be stacked on the metal substrate 10 in a stacking order for pressing. During the pressing process, the insulating groove 13 is filled by the semi-cured adhesive sheet 21 with high resin content and high fluidity, and there is no need to press the semi-cured filling sheet 22 on the second surface 10b of the metal substrate 10.

[0051] Following step S4, step S5 is performed: removing the resin material from both sides of the package substrate obtained in step S4, that is, removing the resin material that has flowed onto both sides of the package substrate during the lamination process. For example, the removal of the resin material can be achieved by grinding both sides of the package substrate (e.g., grinding with a ceramic brush). Furthermore, grinding can also improve the surface flatness of the metal boss 12 and the outer copper foil 32, making them as flush as possible (the height difference is preferably less than 10 μm).

[0052] Combine Figure 1 and Figure 6 As shown, after step S5, step S6 is performed: copper is plated on the entire surface of the package substrate provided with the metal boss 12 to form a copper clad layer 33 that connects and covers the metal boss 12 and the outer copper foil 32. The production of the copper clad layer 33 can refer to the existing technology. For example, the method of first chemically plating copper and then electroplating copper, which is commonly used in this field, can be adopted, and will not be described in detail here. In addition, when the circuit substrate 30 adopts a double-sided copper-clad core board, through holes can be processed in the circuit substrate before the entire board is copper-plated. While the entire board is copper-plated, copper is plated in the through holes to form conductive holes, so as to achieve electrical connection between the conductive circuits on both sides of the circuit substrate 30.

[0053] In step S7, the copper cladding layer 33 and the outer copper foil 32 are patterned and etched to obtain the conductive structure of the circuit substrate 30 (not shown in the figure). The conductive structure includes an outer conductive circuit formed on the outer surface of the circuit substrate 30. In addition, the patterned etching in step S7 can also form a thermal pad on the metal boss 12. The thermal pad can be formed only on the metal boss 12 or extend laterally to the insulating core board 31.

[0054] Combine Figure 1 and Figure 7As shown, the packaging substrate manufacturing method of the embodiment further includes step S8: drilling insulating holes 100 at locations on the packaging substrate corresponding to the connection bridges 14 (grid nodes of the insulation slots 13) to remove the connection bridges 14 and achieve electrical insulation between the multiple metal heat conducting units 11. Preferably, the area of ​​the insulating holes 100 is larger than the area of ​​the connection bridges 14 to ensure that the connection bridges 14 are completely removed.

[0055] Example 2

[0056] like Figure 8 As shown, the difference between Example 2 and Example 1 is that in Example 2, step S1 forms a plurality of metal bosses 12 on both the first surface 10a and the second surface 10b opposite to the first surface 10a of the metal substrate 10; and step S4 simultaneously presses the prepreg sheet 21 and the circuit substrate 30 onto both the first surface 10a and the second surface 10b of the metal substrate 10. For other descriptions of Example 2, refer to Example 1.

[0057] Referring to the above description, the packaging substrate obtained by the manufacturing method of the present invention includes a metal substrate 10 and a circuit substrate 30 provided with a conductive structure. The metal substrate 10 and the circuit substrate 30 are bonded together by a semi-cured bonding sheet 21. The circuit substrate 30 is provided with a plurality of through holes 310, and the metal substrate 10 has a plurality of metal bosses 12 arranged in the through holes 310; a grid-shaped insulating groove 13 is provided in the metal substrate 10 and passes through the metal substrate 10, and the insulating groove 13 is filled with resin material 20; a metal heat-conducting unit 11 is formed inside each grid of the insulating groove 13, and a plurality of metal bosses 12 are correspondingly arranged on the plurality of metal heat-conducting units 11; insulating holes 100 are provided at the positions of the grid nodes corresponding to the insulating grooves 13 in the packaging substrate to achieve electrical insulation between the plurality of metal heat-conducting units 11.

[0058] Compared to the conventional structure of embedding heat-conducting components within an insulating substrate in the prior art, the package substrate of the present invention adopts a reverse embedding structure, whereby the insulating resin material 20 is embedded within the insulating grooves 13 of the metal substrate 10, cleverly achieving a dense distribution of the metal heat-conducting units 11. Furthermore, the metal heat-conducting units 11 are provided with metal bosses 12 for connecting to heating elements. The heat generated by the heating elements can be rapidly conducted through the metal heat-conducting units 11, giving the package substrate the advantage of excellent heat dissipation performance. In addition, the provision of the metal bosses 12 allows the use of a larger circuit substrate 30, which helps to increase the wiring area of ​​the circuit substrate 30 and provide sufficient wiring space for the densely distributed heating elements.

[0059] It should be noted that for the sake of simplicity, some identical descriptions in the above different embodiments have been omitted. Unless there are any contradictions or exclusions, the different embodiments disclosed above can be referenced, referred to, or combined with each other, and the technical features / components of different embodiments can also be combined and / or replaced with each other.

[0060] Although the present invention has been disclosed above with reference to specific embodiments, these embodiments are not intended to limit the scope of the present invention. Any person skilled in the art may make modifications or substitutions without departing from the scope of the present invention. In other words, any equivalent modifications made in accordance with the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for manufacturing a packaging substrate, characterized in that The steps include: S1, processing a plurality of metal bosses on at least one surface of a metal substrate; S2, machining a grid-shaped insulating groove penetrating the metal substrate in the metal substrate; wherein the grid nodes of the insulating groove form a connecting bridge, each grid of the insulating groove forms a metal heat conducting unit inside, and the plurality of metal bosses are correspondingly arranged on the plurality of metal heat conducting units; S3, machining through holes at positions corresponding to the metal bosses on the prepreg bonding sheet and the circuit substrate having at least an outer copper foil layer; S4, pressing the prepreg and the circuit substrate together on the surface of the metal substrate provided with the metal boss, and simultaneously filling the insulating groove with a resin material during the pressing process; S5, removing the resin material on both sides of the packaging substrate obtained in step S4; S6, performing copper plating on the entire surface of the packaging substrate provided with the metal bosses to form a copper cladding layer connecting and covering the metal bosses and the outer copper foil; S7, performing patterned etching on the copper cladding layer and the outer copper foil; S8, drilling insulating holes on the packaging substrate at positions corresponding to the connection bridges to remove the connection bridges and achieve electrical insulation between the plurality of metal heat-conducting units.

2. The method for manufacturing a package substrate according to claim 1, wherein: Step S1 processes the metal boss on the first surface of the metal substrate, and step S4 presses the prepreg filling sheet on the second surface of the metal substrate opposite to the first surface while pressing the prepreg bonding sheet and the circuit substrate.

3. The method for manufacturing a package substrate according to claim 2, wherein: The resin content of the prepreg filling sheet is higher than that of the prepreg bonding sheet.

4. The method for manufacturing a package substrate according to claim 3, wherein: In step S4 , the prepreg filling sheet is stacked on the metal substrate, and the prepreg bonding sheet and the circuit substrate are stacked under the metal substrate.

5. The method for manufacturing a package substrate according to claim 1, wherein: Step S1 processes a plurality of metal bosses on the first surface of the metal substrate and on a second surface opposite to the first surface; and step S4 simultaneously presses the semi-cured adhesive sheet and the circuit substrate on the first surface and the second surface of the metal substrate.

6. The method for manufacturing a package substrate according to claim 1, wherein: The circuit substrate is further provided with an inner copper foil; before the step S4 of laminating the prepreg bonding sheet and the circuit substrate, a conductive circuit is first processed in the inner copper foil.

7. The method for manufacturing a package substrate according to claim 1, wherein: In step S1, the metal boss is obtained by partially etching the metal substrate; in step S2, the insulating groove is obtained by laser cutting the metal substrate, and the width of the insulating groove is 0.2 mm to 0.5 mm.

8. The method for manufacturing a package substrate according to claim 1, wherein: The metal substrate is a copper substrate.

9. A packaging substrate comprising a metal substrate and a circuit substrate having a conductive structure, the metal substrate and the circuit substrate being bonded together via a prepreg adhesive sheet, the circuit substrate having a plurality of through holes, and the metal substrate having a plurality of metal bosses disposed within the through holes; characterized in that: The metal substrate is provided with a grid-shaped insulation groove penetrating the metal substrate, and the insulation groove is filled with a resin material; each grid of the insulation groove forms a metal heat-conducting unit, and the plurality of metal bosses are correspondingly provided on the plurality of metal heat-conducting units; Insulation holes are provided in the packaging substrate at positions corresponding to grid nodes of the insulation slots to achieve electrical insulation between the plurality of metal heat-conducting units.

10. The packaging substrate according to claim 9, wherein: The metal substrate is a copper substrate; the width of the insulating groove is 0.2 mm to 0.5 mm.

Images