Ultrathin circuit board with high uniformity and high reliability

Abstract

The utility model discloses an ultrathin circuit board with high uniformity and high reliability, which comprises a signal layer, a single dielectric layer is laminated on the lower surface of the signal layer, vertical interconnection holes penetrate through the dielectric layer and the signal layer, a bonding pad is attached to the lower surface of the dielectric layer, and the vertical interconnection holes are electrically connected with the bonding pad. According to the utility model, the problem of stub caused by the drilling precision tolerance in the traditional back drilling process can be effectively solved, the stability of high-frequency signal transmission is effectively improved, special treatment is carried out on a steel plate adopted during pressing, a frame is designed for bearing, the uniformity of pressing flow glue is improved, the product is ensured not to generate layered plate explosion after being subjected to three times of reflow soldering, and the product quality is improved. And the product reliability is improved, and stable operation in high-temperature and high-humidity environments and the like is met.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of circuit board, concretely relates to a high uniformity high reliability ultra -thin circuit board. BACKGROUND

[0002] As the core carrier of new generation electronic packaging technology, ultra -thin interconnection laminated module circuit board is leading electronic equipment to develop towards lighter, higher performance. This technology realizes high density integration of electronic components through multi -layer precision interconnection structure, provides key support for 5G communication, artificial intelligence, internet of things and other frontier scientific and technological fields. Its unique vertical interconnection structure greatly shortens the signal transmission path, effectively improves the high frequency signal transmission quality. In market application, this technology has been widely used in smart phones, wearable devices, automobile electronics and other fields. Taking folding screen mobile phone as an example, ultra -thin interconnection laminated module circuit board not only meets the demand of equipment to light and thin, but also ensures the stability of high frequency signal transmission. With the popularization of 5G technology and the explosive growth of internet of things equipment, it is expected that the global market size will break through 10 billion US dollars by 2025. Looking to the future, ultra -thin interconnection laminated module circuit board will continue to develop towards higher density and higher performance. The research and development of new materials, the breakthrough of 3D integration technology and the deep integration with semiconductor process will bring more innovation opportunities to the field, and promote electronic equipment to evolve towards more intelligent and more miniaturization.

[0003] However, the traditional back drilling process is easy to cause signal line residual residual pile, causes high frequency signal transmission loss, seriously affects signal integrity, and the dielectric material performs poorly in uniformity and reliability, which is difficult to meet the long-term stable operation of ultra -thin circuit board in harsh environments such as high temperature and high humidity. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing a kind of high uniformity high reliability ultra -thin circuit board to solve the technical defects of existing ultra -thin circuit board, traditional back drilling process is easy to cause signal line residual residual pile, causes high frequency signal transmission loss, seriously affects signal integrity and reliability.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical scheme:

[0006] A kind of high uniformity high reliability ultra -thin circuit board, including signal layer, single layer dielectric layer is laminated in the lower surface of the signal layer, vertical interconnection hole is passed through in dielectric layer and signal layer, dielectric layer lower surface is attached with solder pad, vertical interconnection hole is electrically connected with solder pad.

[0007] As a preferred scheme of the utility model, the surface of solder pad is covered with thiol organic protective layer.

[0008] As the preferred scheme of the utility model, the inside of the lower surface of the signal layer is equipped with a U-shaped isolation groove, the U-shaped isolation groove is formed by alkaline potassium permanganate solution oxidation corrosion, and the U-shaped isolation groove is filled with hydrophilic epoxy resin and is flush with the surface of the signal layer.

[0009] As the preferred scheme of the utility model, the U-shaped isolation groove can block the penetration of the electroplating solution through the hydrophilic epoxy resin during the electroplating process, and an isolation ring is generated by electroplating for blocking the electrical connection between the signal layer and the defective end.

[0010] As the preferred scheme of the utility model, the dielectric layer is dispersed with a high-toughness resin matrix, and the edge area of the dielectric layer is symmetrically embedded with a frame plate, the material of the frame plate is consistent with the dielectric layer, and the thickness is the same as the dielectric layer.

[0011] As the further scheme of the utility model, the dielectric layer is pressed by a steel plate with a sandblasted surface, and the dielectric layer is baked by inert gas after forming.

[0012] Compared with the prior art, the utility model provides a kind of high uniformity high reliability ultra-thin circuit board with the following beneficial effects: the utility model effectively solves the problem that residual pile still exists due to the problem of drilling precision tolerance under traditional back drilling process, improves the stability of high-frequency signal transmission, specially processes the steel plate used during pressing, designs frame bearing strip, improves the uniformity of pressing flow glue, ensures that product does not produce delamination explosion plate after three times reflow soldering, improves the reliability of product, can meet stable operation under high temperature and high humidity environment. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical scheme of the embodiments of the utility model, the drawings needed in the embodiments will be briefly introduced as follows: obviously, the drawings in the following description are only one case of the embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor.

[0014] Figure 1 It is a structural schematic view of the embodiment of the utility model;

[0015] Figure 2 It is a structural schematic view of signal layer in the embodiment of the utility model;

[0016] Figure 3 It is a structural schematic view of dielectric layer in the embodiment of the utility model;

[0017] Figure 4 It is a structural schematic view of U-shaped isolation groove in the embodiment of the utility model.

[0018] Reference signs:

[0019] 1. Signal layer; 101. Dielectric layer; 102. U-shaped isolation groove; 2. Vertical interconnect hole; 3. Pad; 4. Frame board. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0021] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0022] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present invention should be understood according to the specific circumstances.

[0023] See appendix Figures 1-4 As shown in the figure, this utility model provides an ultra-thin circuit board with high uniformity and high reliability, including a signal layer 1. A single dielectric layer 101 is laminated on the lower surface of the signal layer 1. Vertical interconnect holes 2 penetrate the dielectric layer 101 and the signal layer 1. A pad 3 is attached to the lower surface of the dielectric layer 101, and the vertical interconnect holes 2 are electrically connected to the pad 3. The surface of the pad 3 is covered with a thiol-based organic protective layer. A U-shaped isolation groove 102 is provided inside the lower surface of the signal layer 1. The U-shaped isolation groove 102 is formed by oxidation and corrosion with an alkaline potassium permanganate solution. The U-shaped isolation groove 102 is filled with hydrophilic epoxy resin and is flush with the surface of the signal layer 1. During the electroplating process, the hydrophilic epoxy resin in the U-shaped isolation groove 102 can prevent the electroplating solution from penetrating, and the electroplating generates an isolation ring to block the electrical connection between the signal layer 1 and the defective end.

[0024] The dielectric layer 101 has good insulation properties, which isolates the signal layer 1 from the rest of the part, effectively preventing crosstalk between signals and ensuring the accuracy and stability of signal transmission. The vertical interconnect hole 2 penetrates the signal layer 1 and is electrically connected to the single-layer dielectric layer 101 and the pad 3, which can reduce crosstalk and impedance change between signal layers 1 and reduce high-frequency transmission loss.

[0025] The surface of the pad 3, which adopts the above technical solution, is covered with a thiol-based organic protective layer, which can block the penetration of oxygen and moisture, thereby effectively delaying the corrosion of the plating layer in various environments, improving the corrosion resistance of the pad 3, ensuring the reliability of the connection between the pad 3 and other electronic components, improving the welding reliability and service life of the product, and facilitating the use of a highly uniform and reliable ultra-thin circuit board.

[0026] The U-shaped isolation groove 102 formed by the oxidative corrosion characteristics of the alkaline potassium permanganate solution enables the signal layer line to automatically form an isolation ring with the residual stud after electroplating, which can avoid signal transmission loss caused by the residual signal line.

[0027] To further improve the transmission stability of the circuit board, the hydrophilic epoxy resin in the U-shaped isolation groove 102 can block the penetration of the electroplating solution during electroplating and form an electroplating isolation ring on the inner wall, thereby blocking the electrical connection between the signal layer 1 and the residual stake end or the missing end. This avoids signal interference and transmission instability problems that may be caused by the electrical connection between the signal layer 1 and the residual stake end, and effectively improves the stability of its high-frequency signal transmission.

[0028] See appendix Figures 3 to 4 As shown, a high-toughness resin matrix is ​​provided within the dielectric layer 101, and a frame plate 4 is symmetrically embedded in the edge region of the dielectric layer 101. The frame plate 4 is made of the same material as the dielectric layer 101 and has the same thickness. The dielectric layer 101 is laminated using a steel plate with a sandblasted surface, and the dielectric layer 101 is baked with an inert gas after molding.

[0029] To enhance high toughness and bending resistance, a high-toughness resin matrix is ​​filled within the dielectric layer 101. This matrix strengthens the mechanical properties of the dielectric layer 101, enabling it to better withstand various stresses. A symmetrically embedded frame plate 4 is formed at the edge of the dielectric layer 101, with a material thickness consistent with the dielectric layer 101. During lamination, this frame plate balances the flow of the adhesive, effectively improving the toughness and stress resistance of the dielectric layer 101 and preventing cracking or delamination during processing and use. The frame plate 4 also balances the adhesive flow, improving the uniformity of the lamination adhesive flow and resulting in a more uniform thickness of the dielectric layer 101. This enhances the overall performance and reliability of the circuit board. Baking in an inert gas environment reduces the impact of oxygen and other gases on the dielectric layer 101 material, preventing oxidation and other adverse reactions during baking. Furthermore, appropriate baking temperature and conditions facilitate the curing and stress release of the dielectric layer 101 material, making its performance more stable and ensuring that the product does not experience delamination or board breakage after multiple reflow soldering processes, further improving product reliability.

[0030] The embodiment of the utility model effectively solves the problem of residual pile due to the problem of drilling precision tolerance under the traditional back drilling process, effectively improves the stability of high frequency signal transmission, specially processes the steel plate used during pressing, designs a frame bearing strip, improves the uniformity of pressing glue flow, ensures that the product does not produce layered explosion plate after three times of reflow soldering, improves the reliability of the product, and can meet the stable operation under high temperature and high humidity environment.

[0031] The embodiment of the utility model is used, directly connect to the solder pad 3 through the signal layer 1 vertical interconnection hole 2, shorten the signal transmission path, the U type isolation groove 102 is accurately formed through chemical corrosion, the filled hydrophilic base epoxy resin blocks the penetration of electroplating liquid during electroplating, automatically generates an isolation ring, completely blocks the signal path of residual pile, improves the signal integrity, the symmetrically embedded frame plate 4 balances the pressing glue flow, combines sandblasting steel Ra1.5-2.0 mu m to optimize the distribution of glue, and ensures the uniformity of the thickness of the dielectric layer 101.

[0032] The basic principle of the present application is shown and described above, and the above is only the preferred embodiment of the present application, and does not limit the present application, and the above embodiment and the description in the specification only illustrate the principle of the present application, and any modification, equivalent replacement and improvement within the scope of the present application should be included in the protection scope of the present application.

Claims

1. A high-uniformity and high-reliability ultra-thin circuit board comprising a signal layer (1), characterized in that: The signal layer (1) is laminated with a single dielectric layer (101) on the lower surface, the dielectric layer (101) is provided with vertical interconnection holes (2) through the signal layer (1), the lower surface of the dielectric layer (101) is attached with a solder pad (3), and the vertical interconnection holes (2) are electrically connected with the solder pad (3). ​ 2. The high-uniformity and high-reliability ultra-thin circuit board according to claim 1, characterized in that: The surface of the solder pad (3) is covered with a thiol organic protective layer.

3. The high-uniformity and high-reliability ultra-thin circuit board according to claim 1, characterized in that: The lower surface of the signal layer (1) is internally provided with a U-shaped isolation groove (102), the U-shaped isolation groove (102) is formed by oxidation corrosion of an alkaline potassium permanganate solution, the U-shaped isolation groove (102) is filled with a hydrophilic epoxy resin and is flush with the surface of the signal layer (1).

4. The high-uniformity and high-reliability ultra-thin circuit board according to claim 3, characterized in that: The U-shaped isolation groove (102) can block the penetration of the electroplating solution through the hydrophilic epoxy resin in the electroplating process, and an isolation ring is generated by electroplating to block the electrical connection between the signal layer (1) and the defective end.

5. The high-uniformity and high-reliability ultra-thin circuit board according to claim 1, characterized in that: The dielectric layer (101) is dispersed with a high-toughness resin matrix, and the edge area of the dielectric layer (101) is symmetrically embedded with a frame plate (4), the material of the frame plate (4) is consistent with that of the dielectric layer (101), and the thickness of the frame plate (4) is the same as that of the dielectric layer (101).

6. The high-uniformity and high-reliability ultra-thin circuit board according to claim 5, characterized in that: The dielectric layer (101) is pressed by a steel plate with a sandblasted surface.

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