CN120812848A

CN120812848A - Metallized ceramic circuit board and manufacturing method thereof

Info

Publication number: CN120812848A
Application number: CN202510958428.5A
Authority: CN
Inventors: 林义原; 吴思翰; 施建宇
Original assignee: Tong Hsing Electronic Industries Ltd
Current assignee: Tong Hsing Electronic Industries Ltd
Priority date: 2025-01-22
Filing date: 2025-07-11
Publication date: 2025-10-17

Abstract

The present invention discloses a metallized ceramic circuit board and a method for manufacturing the same. The metallized ceramic circuit board comprises a ceramic substrate, a seed layer formed on the ceramic substrate, and a patterned circuit formed on the seed layer. The ceramic substrate has a first board surface, a second board surface located on the opposite side of the first board surface, a plurality of first blind holes recessed in the first board surface, and a plurality of second blind holes recessed in the second board surface. Each of the second blind holes is connected to one of the first blind holes to form a through hole, and they are truncated in a cone shape as they approach each other. The seed layer covers the hole wall of each through hole, and the patterned circuit is formed on the seed layer by direct copper plating and fills a plurality of the through holes. Thus, by adopting a ceramic substrate to replace the existing silicon substrate or glass substrate, the heat dissipation and bending resistance of the metallized ceramic circuit board are effectively improved.

Description

Metallized ceramic circuit board and manufacturing method thereof

Technical Field

The present invention relates to circuit boards, and more particularly, to a metallized ceramic circuit board and a method of manufacturing the same.

Background

Most of the existing circuit boards adopt silicon substrates or glass substrates, so that the heat dissipation and bending resistance of the existing circuit boards are limited by the silicon substrates and the glass substrates and are difficult to improve. Accordingly, the present inventors considered that the above-mentioned drawbacks can be ameliorated, and proposed an invention which is reasonable in design and effectively ameliorates the above-mentioned drawbacks.

Disclosure of Invention

The embodiment of the invention provides a metallized ceramic circuit board and a manufacturing method thereof, which can effectively improve the defects possibly generated by the prior circuit board.

The embodiment of the invention discloses a method for manufacturing a metallized ceramic circuit board, which comprises a first drilling step, a second drilling step and a third drilling step, wherein a plurality of first blind holes are formed in a first board surface of a ceramic substrate in a laser drilling mode, and are spaced from each other, so that each first blind hole is tapered in a truncated cone shape in a direction away from the first board surface;

The method comprises a first drilling step, a second drilling step, a patterning step, a direct copper plating step, a patterning step and a plating step, wherein the first drilling step is used for drilling a plurality of first blind holes on a first plate surface of a ceramic substrate at a position corresponding to the first blind holes, the second drilling step is used for forming a plurality of second blind holes at intervals respectively, so that each second blind hole is in a tapered truncated cone shape in a direction far away from the second plate surface, each second blind hole is communicated with the corresponding first blind hole to form a through hole together, a seed layer is formed on the first plate surface, the second plate surface and the hole wall of each through hole, a first shielding layer and a second shielding layer are respectively formed on two opposite sides of the seed layer, the first shielding layer and the second shielding layer expose part of the seed layer, the first shielding layer and the second shielding layer are formed on the hole wall of the through holes, and the direct copper plating step is used for forming a patterning circuit on the part of the seed layer exposed on the first shielding layer and the second shielding layer.

Optionally, the first blind hole and the second blind hole of each through hole are truncated cone-shaped and are arranged in mirror symmetry.

Optionally, the depth of each through hole and the width of each through hole corresponding to the first plate surface are jointly defined to have an aspect ratio greater than or equal to 10.

Optionally, the forming step comprises a deposition step of depositing a copper alloy layer on the first plate surface, the second plate surface and the hole wall of each through hole, and a chemical plating step of forming a copper layer on the copper alloy layer by chemical plating to jointly form a seed layer.

Optionally, the direct copper plating step includes a first copper plating step of forming a first conductive layer by electroplating a portion of the seed layer exposed to the first and second shielding layers, wherein each of the through holes is not filled with the first conductive layer but the first and second blind holes are not connected to each other by the first conductive layer, and a second copper plating step of forming a second conductive layer by electroplating the first conductive layer to jointly form the patterned circuit.

The embodiment of the invention also discloses a manufacturing method of the metallized ceramic circuit board, which comprises a first drilling step, a second drilling step and a third drilling step, wherein a plurality of first blind holes are formed in a first board surface of a ceramic substrate in a laser drilling mode, and are spaced from each other, so that each first blind hole is tapered in a truncated cone shape in a direction away from the first board surface;

The method comprises a first drilling step of forming a first blind hole on a first surface of a ceramic substrate, a second drilling step of forming a plurality of second blind holes at intervals on the second surface of the ceramic substrate corresponding to the plurality of first blind holes by laser drilling, so that each second blind hole is in a tapered truncated cone shape in a direction away from the second surface, and each second blind hole and the corresponding first blind hole are mutually communicated to form a through hole together, a forming step of forming a seed layer on the first surface, the second surface and the hole wall of each through hole, a direct copper plating step of forming a metal layer on the seed layer by electroplating, wherein the metal layer fills up a plurality of through holes and covers the first surface and the second surface, a patterning step of forming a first shielding layer and a second shielding layer on two opposite sides of the metal layer, and exposing part of the metal layer from the first shielding layer and the second shielding layer, and etching the part of the metal layer, which is not covered by the first shielding layer and the second shielding layer, is left, is defined as a patterned circuit.

Optionally, the direct copper plating step includes a first copper plating step of electroplating the seed layer to form a first metal layer, wherein each through hole is not filled with the first metal layer but the first blind hole and the second blind hole are not communicated with each other through the first metal layer, and a second copper plating step of electroplating the first metal layer to form a second conductive layer so as to jointly form the metal layer.

The embodiment of the invention also discloses a metallized ceramic circuit board which comprises a ceramic substrate, a patterning circuit and a metal layer, wherein the ceramic substrate is provided with a first board surface and a second board surface positioned on the opposite side of the first board surface, the ceramic substrate is provided with a plurality of first blind holes which are concavely arranged on the first board surface at intervals and are tapered towards the direction far away from the first board surface, a plurality of second blind holes which are concavely arranged on the second board surface at intervals and are tapered towards the direction far away from the second board surface, each second blind hole is communicated with one first blind hole to jointly form a through hole, a seed layer covers the wall of each through hole, and the patterning circuit is formed on the seed layer in a direct copper plating mode and fills up the through holes.

Optionally, in each through hole, a hole diameter between 20 micrometers and 40 micrometers is formed at the joint of the first blind hole and the second blind hole.

Optionally, the width of each through hole corresponding to the first plate surface is between 50 micrometers and 70 micrometers.

In summary, the metallized ceramic circuit board and the manufacturing method thereof disclosed in the embodiments of the present invention replace the existing silicon substrate or glass substrate by the ceramic substrate, and the ceramic substrate is matched with the seed layer and the patterned circuit, so that the metallized ceramic circuit board can effectively improve the heat dissipation and the bending resistance of the metallized ceramic circuit board on the premise of meeting the circuit layout requirements.

Furthermore, in the metallized ceramic circuit board and the manufacturing method thereof disclosed by the embodiment of the invention, the first blind holes and the second blind holes which are in the shape of truncated cone are formed on the ceramic substrate in a mutually matched manner, so that a plurality of highly dense through holes are formed on the ceramic substrate, and patterning circuits with low line width distances are formed on the ceramic substrate.

For a further understanding of the nature and the technical aspects of the present invention, reference should be made to the following detailed description of the invention and the accompanying drawings, which are included to illustrate and not to limit the scope of the invention.

Drawings

Fig. 1 is a schematic cross-sectional view of a metallized ceramic circuit board according to a first embodiment of the invention.

Fig. 2 is a schematic diagram illustrating a first drilling step of a method for manufacturing a metallized ceramic circuit board according to a first embodiment of the invention.

Fig. 3 is a schematic diagram illustrating a second drilling step of a method for manufacturing a metallized ceramic circuit board according to a first embodiment of the invention.

Fig. 4 is a schematic diagram illustrating a forming step of a method for manufacturing a metallized ceramic circuit board according to a first embodiment of the invention.

Fig. 5 is a schematic diagram illustrating patterning steps of a method for manufacturing a metallized ceramic circuit board according to a first embodiment of the invention.

Fig. 6 is a schematic diagram of a direct copper plating step of a method of manufacturing a metallized ceramic circuit board according to a first embodiment of the invention.

Fig. 7 is a schematic diagram of a direct copper plating step of a method of manufacturing a metallized ceramic circuit board according to a second embodiment of the invention.

Fig. 8 is a schematic diagram illustrating patterning steps of a method for manufacturing a metallized ceramic circuit board according to a second embodiment of the invention.

Fig. 9 is a schematic diagram illustrating an etching step of a method for manufacturing a metallized ceramic circuit board according to a second embodiment of the invention.

Fig. 10 is a schematic diagram illustrating a removal step of a method for manufacturing a metallized ceramic circuit board according to a second embodiment of the invention.

Detailed Description

The following specific examples are presented to illustrate the embodiments of the present invention disclosed herein with respect to a metallized ceramic circuit board and method of making the same, and those skilled in the art will appreciate the advantages and effects of the present invention from the disclosure herein. The invention is capable of other and different embodiments and its several details are capable of modification and variation in various respects, all from the point of view and application, all without departing from the spirit of the present invention. The drawings of the present invention are merely schematic illustrations, and are not intended to be drawn to actual dimensions. The following embodiments will further illustrate the related art content of the present invention in detail, but the disclosure is not intended to limit the scope of the present invention.

It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various elements or features, these elements or features should not be limited by these terms. These terms are used primarily to distinguish one element from another element or feature from another feature. In addition, the term "or" as used herein shall include any one or a combination of more of the associated listed items as the case may be.

Example one

Please refer to fig. 1 to 6, which illustrate a first embodiment of the present invention. The present embodiment discloses a metallized ceramic circuit board 100 and a method of manufacturing the same, and the metallized ceramic circuit board 100 may be produced by implementing the method of manufacturing the metallized ceramic circuit board, but the present invention is not limited thereto. For example, in other embodiments of the invention not shown, the metallized ceramic circuit board 100 may be made by other methods.

It should be noted that, for the sake of understanding the present embodiment, the description will be given below of the metallized ceramic circuit board 100, and then the manufacturing method of the metallized ceramic circuit board will be described. As shown in fig. 1, the metallized ceramic circuit board 100 in this embodiment includes a ceramic substrate 1, a seed layer 2 formed on the ceramic substrate 1, and a patterned circuit 3 formed on the seed layer 2. That is, any circuit board or manufacturing method not employing a ceramic substrate is different from the metallized ceramic circuit board 100 and the manufacturing method thereof according to the present embodiment.

The ceramic substrate 1 has a first plate surface 11 and a second plate surface 12 opposite to the first plate surface 11, and the first plate surface 11 and the second plate surface 12 are parallel to each other and substantially planar in the present embodiment, but the invention is not limited thereto. For example, in other embodiments of the present invention not shown, at least one of the first plate surface 11 and the second plate surface 12 may be planar according to actual requirements.

The ceramic substrate 1 has a plurality of first blind holes 13 formed in the first plate surface 11 at intervals, and a plurality of second blind holes 14 formed in the second plate surface 12 at intervals. Further, the positions of the first blind holes 13 correspond to the positions of the second blind holes 14, and each of the second blind holes 14 is connected to one of the first blind holes 13 to form a through hole 15.

It should be noted that, in the present embodiment, the through holes 15 have substantially the same shape, and the first blind hole 13 and the second blind hole 14 of each through hole 15 are disposed in mirror symmetry with each other, but the invention is not limited thereto. For example, in other embodiments of the present invention not shown, the through holes 15 may have slightly different shapes according to actual needs, or the first blind hole 13 and the second blind hole 14 of each through hole 15 may have slightly different shapes.

In this embodiment, each of the first blind holes 13 has a tapered truncated cone shape (e.g., truncated cone shape) in a direction away from the first plate surface 11, and each of the second blind holes 14 has a tapered truncated cone shape (e.g., truncated cone shape) in a direction away from the second plate surface 12. Furthermore, the depth H of each through hole 15 and the width W thereof corresponding to the first plate surface 11 are collectively defined with an aspect ratio (H/W) greater than or equal to 10.

Further, in each through hole 15, the edges of the first blind hole 13 and the second blind hole 14 adjacent to each other are aligned and connected to each other, and the connection between the first blind hole 13 and the second blind hole 14 may have an aperture D between 20 micrometers (μm) and 40 μm, and the other aperture of the first blind hole 13 corresponding to the first plate 11 (i.e. the width W of the through hole 15 corresponding to the first plate 11) may be between 50 micrometers and 70 micrometers, but the invention is not limited thereto.

The seed layer 2 covers the wall of each through hole 15 and adjacent parts of the first plate surface 11 and parts of the second plate surface 12. Wherein the walls of each through-hole 15 are completely covered by the seed layer 2, but the first blind holes 13 and the second blind holes 14 thereof remain in communication with each other.

Furthermore, the patterned circuit 3 is formed on the seed layer 2 by direct copper plating (DPC) and fills the plurality of through holes 15. It should be noted that the portions of the patterned circuits 3 corresponding to any two through holes 15 may be disposed at intervals or connected to each other according to actual requirements, which is not limited herein.

In addition, the seed layer 2 includes a copper alloy layer 21 (e.g. titanium copper layer or nickel copper layer) formed on the ceramic substrate 1 by deposition, and a copper layer 22 formed on the copper alloy layer 21 by electroless plating, and the patterned circuit 3 is formed on the copper layer 22 by direct copper plating, but the invention is not limited thereto.

As described above, the ceramic substrate 1 may be configured with the first blind holes 13 and the second blind holes 14 having specific configurations to form the through holes 15 having a high aspect ratio, so as to facilitate the ceramic substrate 1 to be formed with a plurality of highly dense through holes 15 (e.g. the pitch defined by the center lines of any two adjacent through holes 15 may be controlled to be more than 90 micrometers), and facilitate the ceramic substrate 1 to be formed with the patterned circuit 3 having a low line width (e.g. the line width may be controlled to be more than 20 micrometers).

The description of the structure of the metallized ceramic circuit board 100 is generally as above, and the following description will next describe the method for manufacturing the metallized ceramic circuit board, and the technical contents of the description of the structure of the metallized ceramic circuit board 100 can be referred to above at the right time.

As shown in fig. 1 to 6, the method for manufacturing the metallized ceramic circuit board in this embodiment (in sequence) includes a first drilling step S110, a second drilling step S120, a forming step S130, a patterning step S140, a direct copper plating step S150, and a removing step S160. Embodiments of the above steps are described below, but the present invention is not limited thereto.

In the first drilling step S110, as shown in fig. 2, a plurality of first blind holes 13 are formed on a first surface 11 of a ceramic substrate 1 by laser drilling using a laser apparatus 200, such that each of the first blind holes 13 has a tapered truncated cone shape (e.g., truncated cone shape) in a direction away from the first surface 11.

In the second drilling step S120, as shown in fig. 3, a plurality of second blind holes 14 are formed at positions of the laser device 200 corresponding to the plurality of first blind holes 13 on a second surface 12 of the ceramic substrate 1, such that each second blind hole 14 is tapered in a truncated cone shape (e.g. a truncated cone shape) away from the second surface 12, and each second blind hole 14 and the corresponding first blind hole 13 are mutually communicated to form a through hole 15.

Further, the first blind hole 13 and the second blind hole 14 of each through hole 15 are disposed in mirror symmetry in the present embodiment, and the depth H of each through hole 15 and the width W of the corresponding through hole 15 are defined together to have an aspect ratio greater than or equal to 10, but the invention is not limited thereto.

It should be noted that, in the present embodiment, the first drilling step S110 and the second drilling step S120 are sequentially performed by a single laser apparatus 200, but the invention is not limited thereto. For example, in other embodiments of the present invention not shown, the first drilling step S110 and the second drilling step S120 may be implemented by two different laser devices 200, and may be partially overlapped in implementation time, so as to improve the overall operation efficiency.

In the forming step S130, as shown in fig. 4, a seed layer 2 is formed on the first plate surface 11, the second plate surface 12, and the walls of each through hole 15. In the present embodiment, the forming step S130 includes a deposition step and an electroless plating step in sequence, but is not limited thereto. For example, in other embodiments of the invention not shown, the seed layer 2 may also be formed in a single layered configuration by a single process.

In more detail, in the implementation of the deposition step, a copper alloy layer 21 is deposited on the first plate 11, the second plate 12, and the wall of each through hole 15, and the deposition method may be physical vapor deposition (physical vapor deposition, PVD), but is not limited thereto. Furthermore, in the electroless plating step, a copper layer 22 is formed on the copper alloy layer 21 by electroless plating to jointly form the seed layer 2.

In the patterning step S140, as shown in fig. 5, a first shielding layer S1 and a second shielding layer S2 are formed on opposite sides of the seed layer 2 (e.g., the copper layer 22), and the first shielding layer S1 and the second shielding layer S2 expose a portion of the seed layer 2, which is formed on the walls of the through holes 15. It should be noted that, the coverage area of the seed layer 2 covered by the first shielding layer S1 and the second shielding layer S2 may be adjusted and changed according to actual requirements, and is not limited to the state shown in the drawings.

In the direct copper plating step S150, as shown in fig. 6, a patterned circuit 3 is formed by the partial plating of the seed layer 2 exposed in the first shielding layer S1 and the second shielding layer S2. In this embodiment, the direct copper plating step S150 includes a first copper plating step and a second copper plating step in sequence, but is not limited thereto. For example, in other embodiments of the invention not shown, the patterned circuit 3 may also be formed into a single-layered structure by a single process.

In more detail, in the implementation of the first copper plating step, a first conductive layer 31 is formed by the partial plating of the seed layer 2 exposed to the first shielding layer S1 and the second shielding layer S2, wherein each through hole 15 is not filled with the first conductive layer 31, but the first blind hole 13 and the second blind hole 14 are not communicated with each other by the first conductive layer 31. In the second copper plating step, a second conductive layer 32 is formed on the first conductive layer 31 by electroplating to jointly form the patterned circuit 3.

In the removing step S160, as shown in fig. 1, the first shielding layer S1 and the second shielding layer S2 are removed, and the coverage area of the seed layer 2 covered by the first shielding layer S1 and the second shielding layer S2 is removed by etching, so as to obtain a metallized ceramic circuit board 100.

Example two

Please refer to fig. 7-10, which illustrate a second embodiment of the present invention. Since this embodiment is similar to the first embodiment, the same parts of the two embodiments will not be described again, and the differences between the present embodiment and the first embodiment are generally described as follows:

The embodiment discloses a manufacturing method of a metallized ceramic circuit board, which (in sequence) comprises a first drilling step, a second drilling step, a forming step, a direct copper plating step S240, a patterning step S250, an etching step S260 and a removing step S270. The first drilling step, the second drilling step, and the forming step of the present embodiment are substantially the same as those of the first embodiment, and are not described herein. Embodiments of the direct copper plating step S240, the patterning step S250, the etching step S260, and the removing step S270 are described below, but the present invention is not limited thereto.

In the direct copper plating step S240, as shown in fig. 7, a metal layer M is formed on the seed layer 2 by electroplating, and fills the through holes 15 and covers the first plate surface 11 and the second plate surface 12. In this embodiment, the direct copper plating step S240 includes a first copper plating step and a second copper plating step in sequence, but is not limited thereto. For example, in other embodiments of the invention not shown, the metal layer M may also be formed into a single-layered structure by a single process.

In more detail, in the implementation of the first copper plating step, a first metal layer M1 is formed on the seed layer 2 by electroplating, wherein each through hole 15 is not filled with the first metal layer M1, but the first blind hole 13 and the second blind hole 14 are not communicated with each other by the first metal layer M1. In addition, in the implementation of the second copper plating step, a second metal layer M2 is formed by electroplating the first metal layer M1 so as to jointly form the metal layer M.

In the patterning step S250, as shown in fig. 8, a first shielding layer S1 and a second shielding layer S2 are formed on opposite sides of the metal layer M, and the first shielding layer S1 and the second shielding layer S2 expose a portion of the metal layer M, which fills the through holes 15. It should be noted that, the area of the first board surface 11 covered by the first shielding layer S1 and the area of the second board surface 12 covered by the second shielding layer S2 may be adjusted and changed according to the actual requirement, and are not limited to the state shown in the drawings.

The etching step S260 is to etch the portion of the metal layer M not covered by the first shielding layer S1 and the second shielding layer S2, as shown in fig. 9, so as to leave the portion of the metal layer M, which is defined as a patterned circuit 3.

In the removing step S270, as shown in fig. 10, the first shielding layer S1 and the second shielding layer S2 are removed to obtain a metallized ceramic circuit board 100.

[ Technical Effect of embodiments of the invention ]

The foregoing disclosure is only illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention, as all changes which come within the meaning and range of equivalency of the description and drawings are therefore intended to be embraced therein.

Claims

1. A method of manufacturing a metallized ceramic circuit board, the method comprising:

A first drilling step of forming a plurality of first blind holes spaced from each other on a first plate surface of a ceramic substrate by laser drilling so that each first blind hole has a truncated cone shape tapering away from the first plate surface;

A second drilling step, in which a plurality of second blind holes are formed at the positions of a second plate surface of the ceramic substrate corresponding to the plurality of first blind holes in a laser drilling way respectively, so that each second blind hole is in a tapered truncated cone shape towards the direction far away from the second plate surface, and each second blind hole and the corresponding first blind hole are mutually communicated to jointly form a through hole;

Forming, namely forming a seed layer on the first plate surface, the second plate surface and the hole wall of each through hole;

A patterning step of forming a first shielding layer and a second shielding layer on opposite sides of the seed layer, respectively, wherein the first shielding layer and the second shielding layer expose a part of the seed layer, which is formed on the walls of the plurality of through holes, and

And a direct copper plating step, namely forming a patterned circuit on the partial plating of the seed layer exposed out of the first shielding layer and the second shielding layer.

2. The method of claim 1, wherein the first and second blind holes of each through hole are truncated cone shaped and are mirror-symmetrical to each other.

3. The method of claim 1, wherein the depth of each through hole and the width of each through hole corresponding to the first plate surface are collectively defined with an aspect ratio of 10 or more.

4. The method of manufacturing a metallized ceramic circuit board according to claim 1, wherein said forming step comprises:

A deposition step of depositing a copper alloy layer on the first plate surface, the second plate surface and the hole wall of each through hole, and

And an electroless plating step, wherein a copper layer is formed on the copper alloy layer through electroless plating so as to jointly form the seed layer.

5. The method of manufacturing a metallized ceramic circuit board according to claim 1, wherein said direct copper plating step comprises:

a first copper plating step of forming a first conductive layer on the part of the seed layer exposed from the first shielding layer and the second shielding layer, wherein each through hole is not filled with the first conductive layer but is not communicated with the first blind hole and the second blind hole through the first conductive layer, and

And a second copper plating step, namely electroplating the first conductive layer to form a second conductive layer so as to jointly form the patterned circuit.

6. A method of manufacturing a metallized ceramic circuit board, the method comprising:

A first drilling step of forming a plurality of first blind holes spaced from each other on a first plate surface of a ceramic substrate by laser drilling, so that each first blind hole is tapered in a truncated cone shape in a direction away from the first plate surface;

a second drilling step, in which a plurality of second blind holes are formed at the positions of a second plate surface of the ceramic substrate corresponding to the plurality of first blind holes in a laser drilling way respectively, so that each second blind hole is tapered in a truncated cone shape towards the direction far away from the second plate surface, and each second blind hole and the corresponding first blind hole are mutually communicated to jointly form a through hole;

a direct copper plating step, namely forming a metal layer on the seed layer in an electroplating way, wherein the metal layer fills up a plurality of through holes and covers the first plate surface and the second plate surface;

A patterning step of forming a first shielding layer and a second shielding layer on opposite sides of the metal layer respectively, wherein the first shielding layer and the second shielding layer expose a part of the metal layer and fill up the plurality of through holes, and

An etching step of etching the metal layer portion uncovered by the first shielding layer and the second shielding layer to leave the portion of the metal layer, the portion being defined as a patterned circuit.

7. The method of manufacturing a metallized ceramic circuit board according to claim 6, wherein said first blind hole and said second blind hole of each of said through holes are truncated cone-shaped and are disposed mirror-symmetrically to each other.

8. The method of manufacturing a metallized ceramic circuit board according to claim 6, wherein the depth of each through hole and the width thereof corresponding to the first plate surface are collectively defined with an aspect ratio of 10 or more.

9. The method of manufacturing a metallized ceramic circuit board according to claim 6, wherein said forming step comprises:

10. The method of manufacturing a metallized ceramic circuit board according to claim 6, wherein said direct copper plating step comprises:

A first copper plating step for electroplating the seed layer to form a first metal layer, wherein each through hole is not filled with the first metal layer but the first blind hole and the second blind hole are not communicated with each other by the first metal layer

And a second copper plating step, namely electroplating the first metal layer to form a second conductive layer so as to jointly form the metal layer.

11. A metallized ceramic circuit board, said metallized ceramic circuit board comprising:

A ceramic substrate having a first plate surface and a second plate surface opposite the first plate surface, and the ceramic substrate having:

a plurality of first blind holes concavely arranged on the first plate surface at intervals, each first blind hole having a tapered truncated cone shape towards the direction away from the first plate surface, and

The second blind holes are concavely arranged on the second plate surface at intervals, and each second blind hole is tapered towards the direction far away from the second plate surface, wherein each second blind hole is communicated with one first blind hole to jointly form a through hole;

a seed layer covering the walls of each of the through holes, and

And a patterned circuit formed on the seed layer by direct copper plating and filling up the plurality of through holes.

12. The metallized ceramic circuit board according to claim 11, wherein said first blind hole and said second blind hole of each of said through holes are both frustoconical and are arranged mirror-symmetrically with respect to each other.

13. The metallized ceramic circuit board according to claim 12, wherein in each of said through holes, a hole diameter between 20 microns and 40 microns is provided at the junction of said first blind hole and said second blind hole.

14. The metallized ceramic circuit board according to claim 11, wherein the depth of each of said through holes and the width thereof corresponding to said first plate surface are collectively defined with an aspect ratio of 10 or more.

15. The metallized ceramic circuit board according to claim 14, wherein said width of each of said through holes corresponding to said first plate face is in the range of 50 microns to 70 microns.