WO2021088336A1

WO2021088336A1 - Fabrication method for pcb having internally embedded ceramic piece, and pcb thereof

Info

Publication number: WO2021088336A1
Application number: PCT/CN2020/087754
Authority: WO
Inventors: 王俊; 沙伟强; 谢光前
Original assignee: 景旺电子科技(龙川)有限公司
Priority date: 2019-11-05
Filing date: 2020-04-29
Publication date: 2021-05-14
Also published as: CN110785028A

Abstract

Disclosed by the present application is a fabrication method for PCB that has an internally embedded ceramic piece and a PCB thereof. According to the present application, a ceramic piece (12) is semi-embedded into a PCB (10), and a semi-cured sheet (13) is added to the upper surface of the ceramic piece (12) and press-fitted. After press-fitting, there is no need for an over-grinding process, as both the sheet (13) and the over-grinding process can ensure the flatness of the upper surface of the PCB (10), and the copper thickness of the upper surface can be controlled to be 0.010-0.020mm, thereby ensuring the fabrication of a precise circuit. That is to say, copper foil (14) is attached to the upper surface of the PCB (10), and the thickness of the copper foil (14) is easy to control, which helps to make a precise circuit.

Description

Method for manufacturing PCB board embedded with ceramic sheets and PCB board thereof

This application requires a Chinese patent filed at the State Intellectual Property Office of the People’s Republic of China on November 5, 2019, with the application number 201911071987.5, and the application titled "A method for manufacturing a PCB board with embedded ceramic sheets and its PCB board" The priority of the application, the entire content of which is incorporated in this application by reference.

Technical field

This application relates to the technical field of PCB board manufacturing technology, and in particular to a method for manufacturing a PCB board embedded with ceramic sheets and the PCB board thereof.

Background technique

With the development of intelligent, miniaturized, and portable power electronic devices, devices with high power and high heat dissipation need more sophisticated wiring design, higher-level stacking and more efficient heat dissipation design. Usually, a groove is cut between the printed circuit board (referred to as "PCB") and the ceramic sheet (mainly alumina or aluminum nitride) is embedded in the PCB. The prepreg is melted and filled between the ceramic sheet and the PCB through a pressing process. gap. After pressing, it is necessary to go through the grinding process to remove the excess resin overflowing on the surface of the ceramic sheet, and then do the drilling, PTH, outer layer circuit and titanium removal process.

In the above process, there are three key points:

1. When the prepreg is melted, the gap between the ceramic and PCB must be completely filled;

2. The excess glue on the ceramic chip needs to be removed;

3. Titanium should be removed after etching the outer circuit.

1 and 2, determine that the copper thickness on the ceramic chip needs to be greater than 35um to ensure that after filling the gap, the copper on the ceramic chip will not be exposed to the base material in the overflow removal process. After PTH, the copper thickness on the ceramic chip It will be greater than 50um, which determines that it cannot be used for precise circuit etching. Secondly, this process must go through the process of removing titanium, otherwise the circuit on the ceramic chip will be short-circuited.

The existing design is that the upper and lower sides of the ceramic sheet are the upper and lower sides of the final PCB. In order to fill the gap between the ceramic sheet and the multilayer PCB, the resin overflow gap of the prepreg must be ensured, and the final grinding method is used to ensure that the ceramic sheet and the PCB The leveling of the room. The grinding process will remove the copper on the ceramic sheet, resulting in exposure of the substrate or insufficient copper thickness. Therefore, the existing manufacturing method will increase the copper thickness on the ceramic chip to 1OZ or 2OZ. If the copper thickness is greater than 1OZ, it is impossible to make a precise circuit (line width/line spacing less than 0.075mm).

technical problem

One of the objectives of the embodiments of the present application is to provide a method for manufacturing a PCB board with embedded ceramic sheets and the PCB board, so as to solve the problem that the existing manufacturing method cannot produce a precise circuit.

Technical solutions

In order to solve the above technical problems, the technical solutions adopted in the embodiments of this application are:

In the first aspect, a method for manufacturing a PCB board with embedded ceramic sheets is provided, which includes the following steps:

Step 1: Provide a PCB board with slots;

Step 2: Attach a high temperature resistant fixed layer on the bottom surface of the PCB board;

Step 3: Provide a ceramic sheet with a size corresponding to the slot hole, and place it in the corresponding slot; one end of the ceramic sheet is connected with the fixing layer so as to be fixed in the slot;

Step 4: Stack the prepreg and copper foil on the top surface of the PCB in turn;

Step 5. Place the PCB with the prepreg and copper foil superimposed on the laminating machine for laminating; after the laminating is completed, the fixed layer is removed to form a PCB with embedded ceramic sheets;

Step 6. Paste dry film on the top and bottom surfaces of the PCB board with ceramic sheets embedded;

Step 7. The copper foil and prepreg on the top surface of the PCB board with the ceramic sheet embedded are processed by the exposure machine, the dry film developing machine, and the acid etching machine to form the laser drilling window;

Step 8: Process a laser hole on the top surface of the PCB board with the ceramic sheet embedded in it by a laser drilling machine;

Step 9: Fill the laser hole with copper plating by means of hole filling electroplating, so as to realize the conduction between the copper foil on the top surface and the embedded ceramic sheet of the PCB board.

In one embodiment, the PCB board is a multi-layer board, and several PCB core boards and prepregs are sequentially stacked and riveted and fixed.

In an embodiment, the thickness of the ceramic sheet is 0.5-2.0 mm, and the ceramic sheet is covered with a copper layer with a thickness of 0.01-0.20 mm.

In an embodiment, the aperture of the laser hole is 0.075-0.150 mm.

In one embodiment, the aperture of the slot is 0.075-0.15 mm; the aperture of the slot is 0.1-0.2 mm larger than that of the ceramic sheet.

In one embodiment, the resin content of the prepreg is 68%-75%, and the thickness is 0.076-0.13mm.

In one embodiment, the thickness of the copper foil is 1/3 OZ or 1/2 OZ.

In an embodiment, the shape of the ceramic sheet is a six-sided cylinder or a square cylinder.

In one embodiment, the laser hole is a blind hole.

In one embodiment, the PCB board superimposed with the prepreg and copper foil is placed in the laminating machine, and the PCB board is laminated through the formation of high temperature, high pressure, and vacuum; the high temperature is 180°C-250°C, and the high pressure is 150Kp/ cm ² -200 Kp/cm ² , vacuum degree is 680mmHg-1000mmHg.

In an embodiment, the number of layers of the multilayer PCB board is 4-20 layers, and the thickness of the multilayer PCB board is 0.5-3.0 mm.

In one embodiment, the fixing layer is high temperature resistant adhesive paper.

In one embodiment, the slot hole is a through hole.

In the second aspect, a PCB board is provided, which is manufactured according to the above-mentioned PCB board manufacturing method.

Beneficial effect

The beneficial effects of the method for manufacturing a PCB board with embedded ceramic sheets provided by the embodiments of the present application are: the ceramic sheets are half-buried in the PCB board in this application, and a prepreg sheet is added on the upper surface of the ceramic sheet. After that, there is no need to go through the grinding process, and the surface of the PCB can be guaranteed to be flat, and the copper thickness of the upper surface can be controlled within 0.010—0.020mm, so as to ensure that precise circuits can be made, that is, copper is pasted on the upper surface of the PCB. The thickness of foil and copper foil is easy to control, which is conducive to making precise circuits.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings that need to be used in the embodiments or exemplary technical descriptions. Obviously, the accompanying drawings in the following description are only of the present application. For some embodiments, those of ordinary skill in the art can obtain other drawings based on these drawings without creative work.

FIG. 1 is a structural diagram of a PCB board manufactured by a method for manufacturing a PCB board with embedded ceramic chips provided by an embodiment of the application.

Embodiments of the present invention

In order to make the purpose, technical solutions, and advantages of this application clearer, the following further describes this application in detail with reference to the accompanying drawings and specific implementations.

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of this application.

In the description of this application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise" and other directions or positions indicated The relationship is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore It cannot be understood as a restriction on this application.

In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present application, "a plurality of" means two or more than two, unless otherwise specifically defined.

In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense. For example, they may be connected or detachable. Or integrated; it can be a mechanical connection, or it can be an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above-mentioned terms in this application can be understood according to specific circumstances.

In this application, unless expressly stipulated and defined otherwise, the "above" or "below" of the first feature of the second feature may include direct contact between the first and second features, or may include the first and second features Not in direct contact but through other features between them. Moreover, "above", "above" and "above" the second feature of the first feature include the first feature being directly above and obliquely above the second feature, or it simply means that the level of the first feature is higher than that of the second feature. The "below", "below" and "below" the first feature of the second feature include the first feature directly below and obliquely below the second feature, or it simply means that the level of the first feature is smaller than the second feature.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean specific features described in conjunction with the embodiment or example , The structure, materials, or characteristics are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above-mentioned terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

Drawing 1 is the drawing of this application.

This implementation provides a method for manufacturing a PCB board with embedded ceramic sheets. Please refer to Figure 1, which includes the following steps:

Step 1: Provide a PCB board 10 with a slot 11;

Step 2: Attach a high temperature resistant fixing layer to the bottom surface of the PCB board 10; optionally, the fixing layer is high temperature resistant adhesive tape;

Step 3: Provide a ceramic sheet 12 with a size corresponding to the slot 11, and place it in the corresponding slot 11; one end of the ceramic sheet 12 is connected with a fixing layer so as to be fixed in the slot 11;

Step 4: Stack the prepreg 13 and the copper foil 14 on the top surface of the PCB board 10 in sequence;

Step 5. Place the PCB board 10 with the prepreg 13 and the copper foil 14 superimposed on the laminating machine for laminating; after the laminating is completed, the fixed layer is removed to form the PCB 10 with the ceramic sheet 12 embedded therein;

Step 6. Paste dry films on the top and bottom surfaces of the PCB board 10 with the ceramic sheet 12 embedded therein;

Step 7. The copper foil 14 and the prepreg 13 on the top surface of the PCB board 10 with the ceramic sheet 12 embedded are processed by an exposure machine, a dry film developing machine, and an acid etching machine to form an opening for laser drilling;

Step 8: Process a laser hole 15 on the top surface of the PCB board 10 in which the ceramic sheet 12 is embedded by a laser drilling machine;

Step 9: Fill the laser hole 15 with copper plating 16 by means of hole filling electroplating, so as to realize conduction between the copper foil 14 on the top surface and the embedded ceramic sheet 12 of the PCB board 10.

Wherein, the PCB board 10 is a multi-layer board, and a plurality of PCB core boards and prepregs are sequentially stacked and riveted and fixed. The prepregs and the stacked prepregs 13 may have the same specifications. A slot 11 is milled at a set position of the multilayer PCB board 10, and the diameter of the slot 11 is slightly larger than that of the ceramic sheet 12. The slot 11 is a through hole or a blind hole. In this embodiment, the slot 11 is a through hole. The upper and lower sides of the multilayer PCB board 10 are both copper foil layers, and the copper foil and the superimposed copper foil here can have the same specifications. Optionally, the number of layers of the multilayer PCB board 10 is 4-20 layers, and the thickness of the multilayer PCB board 10 is 0.5-3.0 mm.

The thickness of the ceramic sheet 12 is 0.5-2.0 mm, and the ceramic sheet 12 is covered with a copper layer with a thickness of 0.01-0.20 mm. The copper layer is used to conduct the multilayer PCB board 10.

Optionally, the aperture of the laser hole 15 is 0.075-0.150 mm. Among them, the laser hole 15 is a blind hole and communicates with the ceramic sheet 12 inside.

Optionally, the aperture of the slot 11 is 0.075-0.15 mm. The aperture size of the slot 11 is larger than that of the ceramic sheet 12 by 0.1-0.2 mm, so that the ceramic sheet 12 can be inserted into the slot 11.

Optionally, the resin content of the prepreg 13 is 68%-75%, and the thickness is 0.076-0.13mm

Optionally, the thickness of the copper foil 14 is 1/3 OZ or 1/2 OZ.

Optionally, the shape of the ceramic sheet 12 is a six-sided cylinder or a square cylinder, which can better match the slot 11.

The PCB board on which the prepreg 13 and the copper foil 14 are superimposed is placed on the laminating machine and then pressed into the PCB board 10 through the formation of high temperature, high pressure and vacuum. The high temperature is 180℃-250℃, the high pressure is 150Kp/cm ² -200Kp/cm ² , and the vacuum degree is 680mmHg-1000mmHg. Under these conditions, the ceramic sheet can be buried in the PCB board seamlessly and in contact. good.

A PCB board is manufactured according to the above-mentioned PCB board manufacturing method. The specific structure is shown in Figure 1.

In this application, the ceramic sheet 12 is half-buried in the PCB board 10, and a prepreg 13 is added to the upper surface of the ceramic sheet 12 to be pressed. After pressing, there is no need to go through the grinding process, which can ensure the flatness of the upper surface of the PCB board 10. And the copper thickness on the upper surface can be controlled within 0.010—0.020mm, so as to ensure that precise circuits can be made. That is, the copper foil 14 is pasted on the upper surface of the PCB board 10, and the thickness of the copper foil 14 is easy to control, which is beneficial to make a precise circuit.

The above are only optional embodiments of the application, and are not used to limit the application. For those skilled in the art, this application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the scope of the claims of this application.

Claims

A method for manufacturing a PCB board with embedded ceramic sheets is characterized in that it comprises the following steps:

Step 1: Provide a PCB board with slots;

Step 2: Attach a high temperature resistant fixed layer on the bottom surface of the PCB board;

Step 3: Provide a ceramic sheet with a size corresponding to the slot hole, and place it in the corresponding slot; one end of the ceramic sheet is connected with the fixing layer so as to be fixed in the slot;

Step 4: Stack the prepreg and copper foil on the top surface of the PCB in turn;

Step 5. Place the PCB with the prepreg and copper foil superimposed on the laminating machine for laminating; after the laminating is completed, the fixed layer is removed to form a PCB with embedded ceramic sheets;

Step 6. Paste dry film on the top and bottom surfaces of the PCB board with ceramic sheets embedded;

Step 7. The copper foil and prepreg on the top surface of the PCB board with the ceramic sheet embedded are processed by the exposure machine, the dry film developing machine, and the acid etching machine to form the laser drilling window;

Step 8: Process a laser hole on the top surface of the PCB board with the ceramic sheet embedded in it by a laser drilling machine;

Step 9: Fill the laser hole with copper plating by means of hole filling electroplating, so as to realize conduction between the copper foil on the top surface and the embedded ceramic sheet of the PCB board.
The method for manufacturing a PCB board with embedded ceramic sheets according to claim 1, wherein the PCB board is a multilayer board, and a plurality of PCB core boards and prepregs are sequentially stacked and fixed by riveting.
The method for manufacturing a PCB board with embedded ceramic sheets according to claim 1, wherein the thickness of the ceramic sheets is 0.5-2.0 mm, and the ceramic sheets are covered with a copper layer with a thickness of 0.01-0.20 mm.
The method for manufacturing a PCB board with embedded ceramic sheets according to claim 1, wherein the diameter of the laser hole is 0.075-0.150 mm.
The manufacturing method of a PCB board with embedded ceramic sheets according to claim 1, wherein the resin content of the prepreg is 68%-75%, and the thickness is 0.076-0.13mm.
The manufacturing method of a PCB board with embedded ceramic sheets according to claim 1, wherein the thickness of the copper foil is 1/3 OZ or 1/2 OZ.
The manufacturing method of a PCB board with embedded ceramic sheets according to claim 1, wherein the shape of the ceramic sheets is a six-sided cylinder or a square cylinder.
The method for manufacturing a PCB board with embedded ceramic sheets according to claim 4, wherein the laser hole is a blind hole.
The method for manufacturing a PCB board with embedded ceramic sheets according to claim 2, wherein the number of layers of the multi-layer PCB board is 4-20 layers, and the thickness of the multi-layer PCB board is 0.5-3.0 mm.
The method for manufacturing a PCB board with embedded ceramic sheets according to claim 1, wherein the PCB board superimposed with prepregs and copper foil is placed in a laminating machine and then formed and pressed by high temperature, high pressure, and vacuum. Composite PCB board; the high temperature is 180°C-250°C, the high pressure is 150Kp/cm 2 -200 Kp/cm 2 , and the vacuum degree is 680mmHg-1000mmHg.
The method for manufacturing a PCB board with embedded ceramic sheets according to claim 1, wherein the fixing layer is high temperature resistant adhesive paper.
The manufacturing method of a PCB board with embedded ceramic sheets according to claim 1, wherein the slot holes are through holes.
A PCB board, characterized in that it is manufactured according to the PCB board manufacturing method of any one of claims 1-12.