Printed circuit board (PCB) with lines embedded in two sides

Abstract

The utility model provides a PCB (Printed Circuit Board) with lines embedded in two sides, and belongs to the technical field of PCBs. The PCB comprises a heat-resistant glue core layer which is provided with a first surface and a second surface opposite to the first surface; the first circuit-embedded single-sided board comprises a third surface for embedding the circuit and a fourth surface which is opposite to the third surface and is not provided with the circuit; the second circuit-embedded single-sided board comprises a fifth surface for embedding the circuit and a sixth surface which is opposite to the fifth surface and is not provided with the circuit; the fourth surface of the first embedded circuit single-sided board is attached to the first surface of the heat-resistant glue core layer; the sixth surface of the second embedded circuit single-sided board is attached to the second surface of the heat-resistant glue core layer; and a metal via hole is formed in the PCB, penetrates through the heat-resistant glue core layer and is communicated with the first buried circuit and the second buried circuit. According to the PCB with the lines embedded in the two sides, the thinning of the board and the high flatness of the surface of the board can be realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of PCB boards, in particular to a PCB board with circuits embedded on both sides. Background Art

[0002] The existing double-sided embedded circuit board structure sandwiches a prepreg sheet between two single-sided boards with embedded circuits. Under high temperature and high pressure, the resin in the prepreg sheet liquefies and cross-links, combining the two single-sided boards into a double-sided board. Metal interconnects are then formed on the double-sided board. If the two single-sided boards are made of different materials and have mismatched thermal expansion coefficients, the double-sided board is prone to warping after the high temperature and high pressure treatment, making it impossible to assemble the product. Summary of the Invention

[0003] In response to the deficiencies of the above-mentioned prior art, an embodiment of the present invention aims to provide a PCB board with embedded circuits on both sides. Two single-sided boards with embedded circuits are pressed together at room temperature and attached to the two sides of a heat-resistant adhesive layer, respectively, to form a double-sided board with a "sandwich" structure. Since they have not undergone high-temperature treatment, the double-sided boards pressed together at room temperature will not warp or deform. The overall thickness of the heat-resistant adhesive layer is 0.020~0.070mm micrometers, which is very thin and hardly increases the thickness of the PCB board when embedded in the PCB board. The heat-resistant adhesive layer has excellent electrical insulation properties and can be laser ablated or machined to form holes, which does not affect the formation of a metal conductive interconnection structure of the "sandwich" double-sided board. Therefore, using a heat-resistant adhesive to bond two single-sided boards with embedded circuits to form a double-sided board can achieve thinning of the board and highly flattening of the surface.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A double-sided embedded circuit PCB board belongs to the technical field of PCB boards. The double-sided embedded circuit PCB board is composed of two embedded circuit single-sided boards and a heat-resistant adhesive core layer. The heat-resistant adhesive core layer has a first surface and a second surface opposite to the first surface. The embedded circuit single-sided board has a surface with embedded circuits and an opposite, circuit-free surface. The circuit-free surfaces of the two embedded circuit single-sided boards are respectively bonded to the first and second surfaces of the heat-resistant adhesive core layer. Metallized holes are provided in the PCB board, passing through the heat-resistant adhesive core layer and connecting the two layers of circuits embedded on the board surface.

[0006] As a further improvement of the present invention: the metallized hole is a blind hole.

[0007] As a further improvement of the present invention: the metallized hole is an X-shaped hole.

[0008] As a further improvement of the present invention: the metallized hole is an H-shaped hole.

[0009] As a further improvement of the present invention, the H-shaped hole may be filled with conductive paste.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] This utility model laminates two single-sided boards with embedded circuits onto the opposite sides of a heat-resistant adhesive layer at room temperature to create a double-sided board with a "sandwich" structure. Because it is not subjected to high-temperature treatment, the double-sided boards will not warp or deform. The overall thickness of the heat-resistant adhesive layer is very thin, ranging from 0.020 to 0.070 mm, and its embedding within the PCB barely increases the board's thickness. The heat-resistant adhesive layer provides excellent insulation and does not interfere with the metal interconnect structure of the "sandwich" double-sided board. This results in an ultra-thin, highly flat double-sided board with embedded circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a cross-sectional schematic diagram of a PCB board with double-sided embedded circuits according to the present invention;

[0013] Figure 2 This is a schematic cross-sectional view of a PCB board with a metallized blind via penetrating the present invention;

[0014] Figure 3 This is a schematic cross-sectional view of a PCB board with a metallized X-shaped hole penetrating the present invention;

[0015] Figure 4 This is a schematic cross-sectional view of a PCB board with a metallized H-shaped hole penetrating the present invention;

[0016] Figure 5 This is a schematic cross-sectional view of a PCB board with conductive paste filled in the metallized holes of the present invention.

[0017] In the figure: 110-heat-resistant adhesive layer, 111-first single-sided board, 112-second single-sided board, 113-third surface, 114-fifth surface, 1a-first buried circuit, 2b-second buried circuit, 2c-metallized blind via, 2d-metallized X-shaped via, 2e-metallized H-shaped via, 2f-metallized via filled with conductive paste DETAILED DESCRIPTION

[0018] The technical solution of this patent is further described in detail below in conjunction with specific implementation methods.

[0019] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] like Figure 1 As shown, a double-sided embedded circuit PCB includes a first single-sided board 111, a second single-sided board 112, and a heat-resistant adhesive core layer 110 sandwiched between the two single-sided boards.

[0021] The first single-sided board 111 includes a first buried circuit 1a and a second dielectric layer. The first buried circuit 1a is located on a third surface 113 of the first single-sided board, with the fourth surface opposite the third surface. The second single-sided board 112 includes a second buried circuit 2b and a third dielectric layer. The second buried circuit 2b is located on a fifth surface 114 of the second single-sided board, with the sixth surface opposite the fifth surface.

[0022] The heat-resistant adhesive core layer 110 includes a first dielectric layer having a first surface and a second surface opposite to the first surface.

[0023] The fourth surface of the first single-sided board 111 is bonded to the first surface of the heat-resistant adhesive core layer 110 , and the sixth surface of the second single-sided board 112 is bonded to the second surface of the heat-resistant adhesive core layer 110 .

[0024] The first medium layer includes a first filling material, the second medium layer includes a second filling material, and the third medium layer includes a third filling material. The second and third filling materials are filling particles or filling fibers, and the first filling material is filling particles.

[0025] The thickness of the heat-resistant adhesive core layer 110 is 0.020-0.070 mm. A metallized hole 2 is provided on the core layer, penetrating the PCB board.

[0026] like Figure 1 As shown, the upper and lower ends of the metallized hole 2 are connected to the circuit 1a and the circuit 2b on the back of the board respectively. The metallized hole 2 passes through the heat-resistant adhesive core layer 110 to form a metal conductive interconnection structure.

[0027] like Figure 2 As shown, the metallization 2 may be a blind hole 2c.

[0028] like Figure 3 As shown, the metallization 2 may be an X-shaped hole 2d.

[0029] like Figure 3 As shown, the metallization 2 may be an H-shaped hole 2e.

[0030] like Figure 3 As shown, the metallization 2 may be a metallization hole 2f filled with conductive paste.

[0031] The above describes in detail the preferred embodiments of this patent, but this patent is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A PCB board with embedded circuits on both sides, characterized in that: include: a heat-resistant adhesive core layer having a first surface and a second surface opposite to the first surface; A first single-sided board includes a third surface with embedded circuits and a fourth surface opposite to the third surface and without circuits; The second single-sided board includes a fifth surface embedded with circuits and a sixth surface opposite to the fifth surface and without circuits; the fourth surface of the first single-sided board is bonded to the first surface of the heat-resistant adhesive core layer; The sixth surface of the second single-sided board is bonded to the second surface of the heat-resistant adhesive core layer; a metallized hole is set in the PCB board, passing through the heat-resistant adhesive core layer, and connecting the first buried circuit and the second buried circuit.

2. A double-sided embedded circuit PCB according to claim 1, characterized in that: The heat-resistant adhesive core layer includes a first dielectric layer, the first dielectric layer includes a first filling material, the first single-sided board includes a second dielectric layer, the second dielectric layer includes a second filling material, and the second single-sided board includes a third dielectric layer, the third dielectric layer includes a third filling material.

3. A double-sided embedded circuit PCB according to claim 2, characterized in that: The thickness of the heat-resistant adhesive core layer is 0.020-0.070 mm.

4. The double-sided embedded circuit PCB according to claim 2, characterized in that: The first and second filling materials are filling particles or filling fibers, and the third filling material is filling particles.

5. The double-sided embedded circuit PCB according to claim 1, characterized in that: The first single-sided board includes a third surface with embedded circuits and a fourth surface opposite to the third surface with no circuits; the second single-sided board includes a fifth surface with embedded circuits and a sixth surface opposite to the fifth surface with no circuits; the fourth surface of the first single-sided board is bonded to the first surface of the heat-resistant adhesive core layer; the sixth surface of the second single-sided board is bonded to the second surface of the heat-resistant adhesive core layer.

6. The double-sided embedded circuit PCB according to claim 1, characterized in that: The metallized hole passes through the heat-resistant adhesive core layer and connects the first buried circuit and the second buried circuit.

7. The double-sided embedded circuit PCB according to claim 6, characterized in that: The metalized hole is a metal through hole or a metal blind hole.

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