Package substrate and manufacturing method thereof

Abstract

The invention discloses a packaging substrate and a manufacturing method thereof. The packaging substrate comprises a metal substrate and a circuit substrate provided with a conductive structure, the metal substrate and the circuit substrate are bonded and connected through a bonding sheet, the circuit substrate is provided with a plurality of through holes, and the metal substrate is provided with a plurality of metal bosses arranged in the through holes; a latticed insulating groove penetrating through the metal substrate is formed in the metal substrate, and the insulating groove is filled with a resin material; a metal heat conduction unit is formed in each grid of the insulating groove, and the plurality of metal bosses are correspondingly arranged on the plurality of metal heat conduction units; insulation holes are formed in the positions, corresponding to grid nodes of the insulation grooves, in the packaging substrate so as to achieve electric insulation between the multiple metal heat conduction units. The packaging substrate provided by the invention not only can realize dense distribution of the metal heat conduction 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 realizing 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 working, so their packaging substrates are required to have good thermal conductivity. To improve the thermal conductivity, thermal conductive parts such as ceramic blocks and copper blocks can be embedded in the packaging substrate.

[0003] In the prior art, a conventional packaging substrate structure includes a plurality of stacked insulating core boards, and a thermal conductor is embedded in the through holes of the insulating core boards. When manufacturing the packaging substrate, a semi-cured sheet is arranged between the insulating core boards for pressing. During the pressing process, the semi-cured sheet flows and fills into the through holes of the insulating core boards to fix the thermal conductor.

[0004] In some applications, the heating elements on the package substrate are densely distributed. At this time, the heat conductive parts used are small in size and large in number, and the heat conductivity requirements are high. It is difficult to meet the requirements using conventional heat conductive part embedding structures and methods. Summary of the invention

[0005] In order to at least partially solve the problems of the prior art, a first aspect of the present invention provides a method for manufacturing a packaging 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 conduction unit inside, and the plurality of metal bosses are correspondingly arranged on the plurality of metal heat conduction units;

[0008] S3, processing a through hole at a position corresponding to the metal boss on the semi-cured bonding sheet and the circuit substrate provided with at least an outer copper foil;

[0009] S4, pressing the semi-cured adhesive sheet and the circuit substrate 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 side surfaces 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 boss to form a copper cladding layer connecting and covering the metal boss and the outer copper foil;

[0012] S7, performing pattern etching on the copper clad 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, a metal boss and a grid-shaped insulating groove are first processed on the metal substrate, and a metal heat-conducting unit is formed inside each grid, so that a plurality of metal heat-conducting units with dense distribution can be formed; the insulating groove has a non-closed grid structure, and its grid nodes form a connecting bridge to maintain the mutual connection of various parts in the metal substrate, which is convenient for subsequent pressing operations; during the pressing process, the insulating groove is filled with resin material, and after pressing, insulating holes are drilled to achieve electrical insulation between multiple metal heat-conducting units, thereby improving the voltage resistance performance of the package substrate. The metal boss on the metal heat-conducting unit is used to connect the heating element, and the heat generated by the heating element can be quickly conducted through the metal heat-conducting unit, so that the package substrate has the advantage of 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 semi-cured filling sheet is higher than that of the semi-cured bonding sheet. Using the semi-cured bonding sheet and the semi-cured filling sheet with higher resin content and fluidity to fill the insulation groove with resin is beneficial to improving the filling degree of the resin material in the insulation groove.

[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 lamination process.

[0018] According to another specific embodiment of the present invention, step S1 processes a plurality of the 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 obtains 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 and connected 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 the metal substrate is provided with a grid-shaped insulating groove penetrating 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 grid-shaped insulating grooves, the insulating grooves are filled with resin material, and the grid nodes of the insulating grooves are provided with insulating holes, so that a plurality of metal heat-conducting units with dense distribution and mutual electrical insulation can be formed. The metal bosses on the metal heat-conducting units are used to connect the heating element, and the heat generated by the heating element can be quickly conducted through the metal heat-conducting units, so that the packaging substrate has the advantage of 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 in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0028] Figure 2 is a schematic diagram of the front structure of the metal substrate after the boss and the insulating groove are processed in Example 1;

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

[0030] Figure 4is a schematic diagram of the stacked structure when the package substrates are pressed together in Example 1;

[0031] Figure 5 is a schematic diagram of the structure after the packaging substrate is pressed in Example 1;

[0032] Figure 6 This is a schematic diagram of the structure of the packaging substrate after the entire board is copper plated in Example 1;

[0033] Figure 7 is a schematic diagram of the structure of drilling an insulating hole at a position corresponding to the connecting bridge in Example 1;

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

[0035] In the following description, many specific details are explained 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 It is an exemplary flow chart of some steps in the embodiment of the manufacturing method of the present invention, and some steps that are the same as those in the prior art except for the steps shown in the figure are omitted in the exemplary flow chart.

[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, the metal substrate 10 has a first surface 10a and a second surface 10b arranged opposite to each other, and a plurality of metal bosses 12 are processed on the first surface 10a of the metal substrate 10 in step S1. The plurality of metal bosses 12 can be distributed in a two-dimensional array as shown in the figure, or can be distributed radially, and the orthographic projection / cross-sectional shape of the metal bosses 12 can be a rectangle or a circle, etc. The specific distribution mode and shape can be determined according to the use requirements, and the present invention does not limit this.

[0040] Exemplarily, the metal boss 12 can be obtained by partially etching the metal substrate 10. During the local etching, the thickness of the etched area on the surface of the metal substrate 10 is reduced, and the unetched area forms the metal boss 12 accordingly. In addition, the metal boss 12 can be obtained by a local electroplating method, that is, the metal boss 12 is electroplated at a predetermined position of the metal substrate 10. The present invention does not limit the method for making the metal boss 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 before step S1 (for example, when the metal boss 12 is locally electroplated, step S2 can be performed before step S1).

[0042] Specifically, Figure 2 and Figure 3 As shown, the insulating groove 13 penetrates the metal substrate 10 in the thickness direction and has a non-closed grid structure, and its grid nodes form a connecting bridge 14. Each grid (grid unit) forms a metal heat-conducting unit 11. The insulating groove 13 of this grid structure can realize the dense distribution of the metal heat-conducting units 11. A plurality of metal bosses 12 are correspondingly arranged on the plurality of metal heat-conducting units 11 and form a part of the metal heat-conducting units 11; wherein each metal heat-conducting unit 11 may correspond to one metal boss 12, or may correspond to multiple metal bosses 12. Figure 2 The grid structure of the insulating slot 13 is only exemplary, and the size / shape of each grid unit in the grid structure of the insulating slot 13 can be determined according to the overall size and shape of the metal heat conducting unit 11, and the present invention is not limited to this.

[0043] In the present invention, the insulating groove 13 is preferably obtained by a laser cutting method to obtain an insulating groove 13 with a 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 to this. 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, and to maintain the overall integrated structure of the metal substrate 10 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 to this, as long as the various parts of the metal substrate 10 can maintain appropriate connection strength.

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

[0045] In this embodiment, the circuit substrate 30 adopts a single-sided copper-clad core board, including an insulating core board 31 and an outer copper foil 32 disposed on the outer surface of the insulating core board 31; wherein the insulating core board 31 can be a core board containing glass fiber cloth, such as FR-4, FR-15 or other core boards containing glass fiber cloth, but is not limited thereto. As a variation of the embodiment, the circuit substrate 30 can adopt a double-sided copper-clad core board, which includes an inner copper foil disposed on the inner surface of the insulating core board 31 in addition to the outer copper foil 32. Before the semi-cured adhesive sheet 21 and the circuit substrate 30 are pressed onto the metal substrate 10, a conductive circuit can be processed in the inner copper foil.

[0046] In step S4, Figure 4 As shown, the semi-cured bonding sheet 21 and the circuit substrate 30 are pressed on the first surface 10a of the metal substrate 10 provided with the metal boss 12, and the metal boss 12 is embedded in the through hole of the semi-cured bonding sheet 21 and the circuit substrate 30. During the pressing process, the resin material in the semi-cured bonding sheet 21 flows to fill the gap between the circuit substrate 30 and the metal boss 12, and flows into the insulating groove 13.

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

[0048] The resin content of the semi-cured filling sheet 22 is higher than that of the semi-cured bonding sheet 21. Exemplarily, the semi-cured bonding sheet 21 is a semi-cured sheet containing glass fiber cloth, and the semi-cured filling sheet 22 is a semi-cured sheet containing non-woven fabric. Compared with the glass fiber cloth semi-cured sheet, the non-woven fabric semi-cured sheet has a higher resin content, and the non-woven fabric semi-cured sheet has a loose short fiber structure, and has a stronger filling ability for the insulation slot 13, so that the insulation slot 13 can be more reliably filled with the resin material 20. The thickness of the semi-cured filling sheet 22 is preferably above 150 μm, but is not limited thereto.

[0049] Preferably, in step S4, the prepreg filling sheet 22 is stacked on the metal substrate 10, and the prepreg bonding sheet 21 and the circuit substrate 30 are stacked on the metal substrate 10 to facilitate the resin material in the prepreg filling sheet 22 to flow and fill the insulating groove 13. The resin material 20 can not only enhance the structural strength of the package substrate, but also realize the 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 are stacked on the metal substrate 10 in a stacking order for lamination. During the lamination 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] After step S4, step S5 is performed: removing the resin material on both sides of the packaging substrate obtained in step S4, that is, removing the resin material that flows to the two sides of the packaging substrate during the lamination process. Exemplarily, the removal of the resin material can be achieved by grinding the two sides of the packaging substrate (for example, grinding with a ceramic brush). In addition, grinding can also improve the surface flatness of the metal boss 12 and the outer copper foil 32, so that the two can form a mutually flush surface as much as possible (the height difference is preferably less than 10μm).

[0052] Combination Figure 1 and Figure 6 As shown, after step S5, step S6 is performed: copper is plated on the 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 commonly used in the field can be adopted, which will not be described in detail here. In addition, when the circuit substrate 30 adopts a double-sided copper-clad core board, a via hole 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 via hole to form a conductive hole, so as to realize the electrical connection of the conductive lines on both sides of the circuit substrate 30.

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

[0054] Combination Figure 1 and Figure 7As shown, the method for manufacturing a package substrate in the embodiment further includes step S8: drilling insulating holes 100 at positions corresponding to the connecting bridges 14 (grid nodes of the insulating grooves 13) on the package substrate to remove the connecting 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 connecting bridges 14 to ensure that the connecting 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 processes a plurality of metal bosses 12 on the first surface 10a of the metal substrate 10 and the second surface 10b relative to the first surface 10a; and step S4 simultaneously presses the semi-cured bonding sheet 21 and the circuit substrate 30 on the first surface 10a and the second surface 10b of the metal substrate 10. The other descriptions of Example 2 can refer to Example 1.

[0057] With reference 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 and connected 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 penetrating the metal substrate 10 is provided in the metal substrate 10, and the insulating groove 13 is filled with a 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 positions of 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 with the conventional structure of embedding heat-conducting parts in the insulating substrate in the prior art, the package substrate of the present invention adopts a reverse embedding structure, that is, the insulating resin material 20 is embedded in the insulating groove 13 of the metal substrate 10, which cleverly realizes the dense distribution of the metal heat-conducting unit 11. Furthermore, a metal boss 12 for connecting the heating element is provided on the metal heat-conducting unit 11, and the heat generated by the heating element can be quickly conducted through the metal heat-conducting unit 11, so that the package substrate has the advantage of excellent heat dissipation performance. In addition, the provision of the metal boss 12 can use a larger area of ​​the circuit substrate 30, which is conducive to increasing the wiring area of ​​the circuit substrate 30 and providing 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 are omitted. Unless there are contradictory or exclusive situations, 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 is disclosed as above with specific embodiments, these specific embodiments are not intended to limit the scope of the present invention. Any person skilled in the art can make some changes / replacements without departing from the scope of the present invention, that is, all equivalent changes made according to the present invention should be covered by the protection scope 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 conduction unit inside, and the plurality of metal bosses are correspondingly arranged on the plurality of metal heat conduction units; S3, processing a through hole at a position corresponding to the metal boss on the semi-cured bonding sheet and the circuit substrate provided with at least an outer copper foil; S4, pressing the semi-cured adhesive sheet and the circuit substrate 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 side surfaces of the packaging substrate obtained in step S4; S6, performing copper plating on the entire surface of the packaging substrate provided with the metal boss to form a copper cladding layer connecting and covering the metal boss and the outer copper foil; S7, performing pattern etching on the copper clad 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 packaging substrate according to claim 1, wherein: Step S1 is to process the metal boss on the first surface of the metal substrate, and step S4 is to press the semi-cured bonding sheet and the circuit substrate together while pressing the semi-cured filling sheet on the second surface of the metal substrate opposite to the first surface.

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

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

5. The method for manufacturing a packaging substrate according to claim 1, wherein: Step S1 is to process a plurality of the metal bosses on the first surface of the metal substrate and on the second surface relative to the first surface; and step S4 is to simultaneously press 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 packaging substrate according to claim 1, wherein: The circuit substrate is also provided with an inner copper foil; before the step S4 of laminating the semi-cured bonding sheet and the circuit substrate, a conductive circuit is first processed in the inner copper foil.

7. The method for manufacturing a packaging 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 packaging 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 provided with a conductive structure, wherein the metal substrate and the circuit substrate are bonded and connected via a semi-cured bonding 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; characterized in that: The metal substrate is provided with a grid-shaped insulating groove penetrating the metal substrate, and the insulating groove is filled with a resin material; a metal heat-conducting unit is formed inside each grid of the insulating groove, and the plurality of metal bosses are correspondingly arranged 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, characterized in that: The metal substrate is a copper substrate; the width of the insulating groove is 0.2 mm to 0.5 mm.

Images