CN206212398U - Has the ultrathin circuit board of fine rule road - Google Patents

Abstract

A kind of ultrathin circuit board for having fine rule road, it includes：First conductive circuit layer, the second conductive circuit layer, the first insulating medium layer between the first conductive circuit layer and the second conductive circuit layer, the material of the first insulating medium layer is photosensitive resin, first insulating medium layer offers conductive hole, and the conductive hole is used for electrically conduct first conductive circuit layer and the second conductive circuit layer.

Description

Ultra-thin circuit boards with thin traces

technical field

The utility model relates to the field of circuit board production, in particular to an ultra-thin circuit board with thin lines.

Background technique

With the rapid development of electronic products, the printed circuit board as the support of components and the carrier of electrical signals should also gradually become miniaturized, lightweight, high-density and multi-functional, and then the production of fine lines of printed circuit boards put forward higher requirements. The line width of the conventional printed circuit board production process is limited by the thickness of the copper layer. The thinner the copper layer, the thinner the line, so the use of thick copper to make thin lines has its own limitations; and the conductive lines of conventional printed circuit boards are usually reduced. However, limited by the thickness of copper, only thin copper can be used to make thin lines, and after production, the etching factor is poor, and the etching is not clean to form burrs; it is difficult to fill with solder resist ink, and it is easy to generate bubbles and other problems.

Utility model content

In view of this, it is necessary to provide a circuit board capable of solving the above technical problems.

An ultra-thin circuit board with thin lines, comprising: a first conductive circuit layer, a second conductive circuit layer, a first insulating medium layer between the first conductive circuit layer and the second conductive circuit layer, the first insulating The material of the medium layer is photosensitive resin, and the first insulating medium layer is provided with a conductive hole, and the conductive hole is used for electrically connecting the first conductive circuit layer and the second conductive circuit layer.

An ultra-thin circuit board with thin lines, which includes: it includes n conductive circuit layers and n+1 insulating dielectric layers, an insulating dielectric layer is arranged between every two adjacent conductive circuit layers, and is the outermost The surface of the two conductive circuit layers of the first layer is respectively provided with an insulating medium layer. The material of the insulating medium layer is formed by coating and pre-curing the liquid photosensitive resin material. The insulating dielectric layer is provided with at least one conductive hole, which is used to electrically connect two adjacent conductive circuit layers, and one of the insulating dielectric layers on the surface of the outermost conductive circuit layer includes a plurality of second openings , the second opening is used to expose the outermost conductive circuit layer to form a solder pad, wherein, n is a natural number, n≧2.

Compared with the prior art, the utility model provides an ultra-thin circuit board with thin lines, which is used as an intermediate layer between the first conductive line layer and the second conductive line layer and is used to cover the first conductive line layer Both the cover layer and the second conductive circuit layer are made of photosensitive resin material, which reduces the thickness of the final circuit board and realizes the thinning of the circuit board. Due to the high resolution of the photosensitive resin material, the production thin lines.

Description of drawings

Fig. 1 is a cross-sectional view of the copper foil provided by the first embodiment of the present invention and the supporting structure layer attached to the surface of the copper foil.

Fig. 2 is a cross-sectional view of forming a first insulating dielectric layer on the surface of copper foil.

3 is a cross-sectional view of forming a first opening by exposing and developing the first insulating medium layer.

Fig. 4 is a cross-sectional view of a copper plating layer formed by electroplating on the surface of the first insulating dielectric layer.

Figure 5 is a cross-sectional view with the support structure layer removed.

6 is a cross-sectional view of forming a first photosensitive film and a second photosensitive film on the surfaces of the copper plating layer and the copper foil layer, respectively.

7 is a cross-sectional view of forming a first protective layer and a second protective layer by exposing and developing the first photosensitive film and the second photosensitive film respectively.

Figure 8 shows the first conductive circuit layer and the second conductive circuit layer formed on the copper plating layer and the copper foil layer respectively, and the first protective layer and the second protective layer are removed to obtain the first embodiment of the utility model. A cross-sectional view of an ultra-thin circuit board with thin traces.

9 is a cross-sectional view of forming a second insulating medium layer and a third insulating medium layer on the surfaces of the first conductive circuit layer and the second conductive circuit layer, respectively.

10 is a cross-sectional view of a welding pad formed by exposing and developing the second insulating medium layer and the third insulating medium layer.

Fig. 11 is a cross-sectional view of the ultra-thin circuit board with thin lines provided by the second embodiment of the present invention by forming gold pads on the pads.

Fig. 12 is a cross-sectional view of the ultra-thin circuit board with thin lines provided by the third embodiment of the present invention.

Description of main component symbols

Ultra-thin circuit boards with thin traces 100,200,300 copper foil 10 first surface 11 second surface 12 first insulating dielectric layer 14 first opening 140 second opening 109,309 Copper plating 16 second insulating dielectric layer 107 third insulating dielectric layer 167 first conductive circuit layer 101 second conductive line layer 161 Conductive circuit layer 30 insulating dielectric layer 40 support structure layer 20 conductive hole 142,442 first photosensitive layer 103 second photosensitive layer 163 first layer of defense 105 second layer of protection 165 pad 111,311 gold pad 113,313

The following specific embodiments will further illustrate the utility model in conjunction with the above-mentioned accompanying drawings.

detailed description

The ultra-thin circuit board with thin lines provided by the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Please refer to FIG. 8 , which is an ultra-thin circuit board 100 with thin lines provided by the first embodiment of the present utility model. layer 161 , the first insulating medium layer 14 located between the first conductive circuit layer 101 and the second conductive circuit layer 161 . The material of the first insulating medium layer 14 is formed by coating and pre-curing liquid photosensitive resin material, and the first insulating medium layer 14 is provided with a conductive hole 142, and the conductive hole 142 is used for electrically conducting the first conductive circuit. layer 101 and the second conductive circuit layer 161 . The thicknesses of the first conductive circuit layer 101 and the second conductive circuit layer 161 are both between 2 μm-12 μm. The thickness of the first insulating dielectric layer 14 is between 5 μm and 15 μm.

Please refer to FIG. 11 , which shows an ultra-thin circuit board 200 with thin lines according to the second embodiment of the present invention. The ultra-thin circuit board 200 with thin lines is based on the ultra-thin circuit board 100 with thin lines provided in the first embodiment and further includes a second insulating medium layer 107 on the surface of the first conductive line layer 101, and a second insulating medium layer 107 on the surface of the first conductive line layer 101. The third insulating medium layer 167 on the surface of the second conductive circuit layer 161 . The material of the second insulating medium layer 107 and the third insulating medium layer 167 is also formed by coating and pre-curing liquid photosensitive resin material. The thicknesses of the second insulating dielectric layer 107 and the third insulating dielectric layer 167 are both between 5 μm and 15 μm. The second insulating dielectric layer 107 includes a plurality of second openings 109, the second openings 109 expose the first conductive circuit layer 101 to form a solder pad 111, and a gold pad 113 is formed on the surface of the solder pad 111, and the gold pad 113 is made of It is formed by electroplating, and the function of electroplating gold is to protect the pads 111 from oxidation.

Please refer to Fig. 1-11, for the manufacturing method of the ultra-thin circuit board 200 with thin lines, the steps include:

The first step, please refer to FIG. 1 , provides a copper foil 10 , the copper foil 10 is rolled copper foil or electrolytic copper foil, and the thickness of the copper foil 10 is between 2 μm-12 μm. The copper foil 10 includes a first surface 11 and a second surface 12 opposite to each other, and a support structure layer 20 is attached to the first surface 11 by a roll-to-roll process, and the support structure layer 20 is poly Polyethylene Terephthalate (PET), the supporting structure layer 20 is used to reinforce the copper foil 10 to meet the mechanical strength requirements of subsequent processing steps. The material of the supporting structure layer 20 can also be an epoxy resin board containing reinforcing materials, a pure epoxy resin board, a phenolic resin board or a metal plate, etc., of course it is not limited to the above materials, and generally any supporting material can be used as a supporting structure Floor.

The second step: please refer to FIG. 2, a first insulating dielectric layer 14 is formed on the second surface 12 of the copper foil 10. In this embodiment, the first insulating dielectric layer 14 is coated with a liquid by a special coating machine. The photosensitive resin material is formed on the second surface 12 by pre-baking the liquid photosensitive resin material and then pre-curing it. In this way, the thickness of the first insulating medium layer 14 can be controlled. Specifically, the photosensitive resin material may be photosensitive polyimide (Polyimide, PI). Because the thickness of the insulating layer included in the common copper-clad substrate is generally in the range of 15 μm-250 μm, the resulting circuit board will be thicker. In the present utility model, the thickness of the first insulating medium layer 14 formed by coating photosensitive resin material and prebaking photosensitive resin material is between 5 μm-15 μm, preferably 6 μm, which is much smaller than the thickness of the insulating layer included in the copper-clad substrate. , Therefore, it is beneficial to reduce the thickness of the final circuit board formed.

The third step, referring to FIG. 3 , is to expose and develop the first insulating dielectric layer 14 to form a plurality of first openings 140 in the first insulating dielectric layer 14 , and the first openings 140 expose the copper foil 10 .

The fourth step, please refer to FIG. 4 and FIG. 5 , electroplating forms a copper plating layer 16 on the surface of the first insulating dielectric layer 14, and removes the support structure layer 20 after forming the copper plating layer 16, and the copper plating layer 16 is The thickness is between 2 μm-12 μm, preferably, the thickness of the copper plating layer 16 is equal to the thickness of the copper foil. While forming the copper plating layer 16, electroplating copper also fills a plurality of the first openings 140 to form at least one conductive hole 142, and at least one conductive hole 142 is subsequently used to connect the first conductive circuit layer 101 and the second conductive circuit layer 161. Electrical conduction.

In the fifth step, referring to FIGS. 6-8 , the copper foil 10 and the copper plating layer 16 are respectively formed into a first conductive circuit layer 101 and a second conductive circuit layer 161 , thereby obtaining an ultra-thin circuit board 100 with thin circuits. In this embodiment, the first conductive circuit layer 101 and the second conductive circuit layer 161 are both formed by photolithography. The method for forming the first conductive circuit layer 101 and the second conductive circuit layer 161 is as follows:

First, please refer to FIG. 6 , a first photosensitive film layer 103 and a second photosensitive film layer 163 are respectively formed on the surfaces of the copper foil 10 and the copper plating layer 16 , the first photosensitive film layer 103 and the second photosensitive film layer 163 Both are photosensitive films, and are formed on the surface of the copper foil 10 and the copper plating layer 16 after coating and pre-baking by a special coating machine; the resolution of the photosensitive film can reach 2 μm-10 μm, and the photosensitive film is relatively Compared with the dry film, the resolution is higher, and the exposure capability of the exposure machine can reach 6μm, and the line width formed after exposure can reach 6μm, so the light-sensitive photofilm can be used to form thinner conductive lines after exposure and development.

Referring to Fig. 7, the first photosensitive film layer 103 and the second photosensitive film layer 163 are exposed and developed, and the first photosensitive film layer 103 and the second photosensitive film layer 163 form the first protection layer 105 and the second photosensitive film layer 163 respectively. Protective layer 165. The copper foil 10 and the copper plating layer 16 respectively covered by the first protection layer 105 and the second protection layer 165 will not be etched.

Referring to FIG. 8, the copper foil 10 and the copper plating layer 16 not covered by the first protective layer 105 and the second protective layer 165 are etched to obtain the first conductive circuit layer 101 and the second conductive circuit layer 161; After removing the first protective layer 105 and the second protective layer 165, an ultra-thin circuit board 100 with thin lines is obtained.

In the sixth step, please refer to FIG. 9 , forming a second insulating dielectric layer 107 and a third insulating dielectric layer 167 on the surfaces of the first conductive circuit layer 101 and the second conductive circuit layer 161 respectively. The method of forming the second insulating dielectric layer 107 and the third insulating dielectric layer 167 is the same as that of the first insulating dielectric layer 14 . That is, it is formed by coating photosensitive resin material and pre-baking photosensitive resin material by special coating machine.

The seventh step, referring to FIG. 10 , is to form a plurality of second openings 109 in the second insulating dielectric layer 107 . The cross-sectional shape of the second openings 109 is circular, and of course other shapes can be designed as required. The first conductive circuit layer 101 is exposed from the second opening 109, and the exposed first conductive circuit layer is defined as a pad 111. In this embodiment, the pad 111 is a copper pad.

The eighth step, referring to FIG. 11 , is to form a gold pad 113 on the surface of the solder pad, thereby forming the ultra-thin circuit board 200 with thin lines. In this embodiment, the gold pad 113 is formed by electroplating gold. The function of electroplating gold is to protect the pads 111 from oxidation. Certainly, conductive materials such as silver pads and tin pads may also be formed on the pads 111 .

Please refer to FIG. 12 , the third embodiment of the present invention also provides an ultra-thin circuit board 300 with thin circuits, which includes n conductive circuit layers 30 and n+1 insulating dielectric layers 40 . An insulating medium layer 40 is provided between every two adjacent conductive circuit layers 30 , and an insulating medium layer 40 is provided on the surfaces of the two outermost conductive circuit layers 30 , wherein n is a natural number, n≧2.

The material of the insulating medium layer 40 is formed by coating and pre-curing a liquid photosensitive resin material. The thickness of the insulating dielectric layer 40 is between 5 μm-15 μm. The thickness of the conductive circuit layer 30 is 2 μm-12 μm, preferably 6 μm.

The insulating medium layer 40 disposed between every two adjacent conductive circuit layers 30 defines at least one conductive hole 442 , and the conductive hole 442 is used for electrically connecting each adjacent conductive circuit layer 30 . One of the insulating dielectric layers 40 on the surface of the outermost conductive circuit layer 30 includes a plurality of second openings 309, and the second openings 309 are used to expose the conductive circuit layer 30 to form a solder pad 311, and the surface of the solder pad 311 A gold pad 313 is formed, and the function of electroplating gold is to protect the pad from oxidation.

In summary, the ultra-thin circuit board with thin lines provided by the present invention only provides an original copper foil, which is coated on the original copper foil to form an insulating dielectric layer and electroplated on the insulating dielectric layer to form a copper plating layer. The thickness of the final formed circuit board 100, 200, 300 (the thickness of the first conductive circuit plus the thickness of the second conductive circuit layer plus the thickness of the first, second and third insulating medium layer) can be reduced to the minimum 19μm, because the thickness of the insulating dielectric layer and the copper plating layer can be controlled, so that an ultra-thin circuit board can be produced; the insulating dielectric layer is not only used as an intermediate layer between the first conductive line layer and the second conductive line layer, but also It is used for exposure and development to form conductive lines. Since the photosensitive resin material is used to expose and develop conductive lines to form conductive lines, the gap (Pitch) that can be used to form conductive line patterns is narrow; because the photosensitive resin material can be used for exposure and development, repeat the above formation The steps of the insulating dielectric layer and the electroplating copper layer can be fabricated to form a multilayer circuit board.

It can be understood that the above embodiments are only used to illustrate the present utility model, and are not used to limit the present utility model. For those skilled in the art, other corresponding changes and deformations made according to the technical concept of the utility model all fall within the protection scope of the claims of the utility model.

Claims (10)

1. it is a kind of have fine rule road ultrathin circuit board, it includes：First conductive circuit layer, the second conductive circuit layer, positioned at first The first insulating medium layer between conductive circuit layer and the second conductive circuit layer, the material of the first insulating medium layer is the light of liquid Quick resin material is formed by coating and precuring, and first insulating medium layer offers conductive hole, and the conductive hole is used for electrical Turn on first conductive circuit layer and the second conductive circuit layer.

2. the ultrathin circuit board of fine rule road is had as claimed in claim 1, it is characterised in that also including positioned at the first conducting wire Second insulating medium layer of layer surface, and positioned at the 3rd insulating medium layer of the second conductive circuit layer table, second insulation is situated between Matter layer and the photosensitive resin material that the 3rd insulating medium layer is liquid are formed by coating and precuring.

3. the ultrathin circuit board of fine rule road is had as claimed in claim 2, it is characterised in that second insulating medium layer is included Multiple second is open, and the part that second opening exposes first conductive circuit layer is formed as weld pad.

4. the ultrathin circuit board of fine rule road is had as claimed in claim 3, it is characterised in that the weld pad surface is formed with gold pad.

5. the ultrathin circuit board of tool fine rule road as claimed in claim 2, it is characterised in that first insulating medium layer, this The thickness of two insulating medium layers and the 3rd insulating medium layer is between 5 μm -15 μm.

6. the ultrathin circuit board of tool fine rule road as claimed in claim 1, it is characterised in that first conductive circuit layer with this The thickness of two conductive circuit layers is between 2 μm -12 μm.

7. it is a kind of have fine rule road ultrathin circuit board, it includes：It includes n conductive circuit layer and n+1 insulating medium layer, often An insulating medium layer is provided between two adjacent conductive circuit layers, the surface difference in outermost two conductive circuit layer An insulating medium layer is provided with, the material of the insulating medium layer is coated with and precuring shape for the photosensitive resin material of liquid passes through Into the insulating medium layer between being arranged on per two adjacent conductive circuit layers offers at least one conductive hole, the conduction Hole is used for the conductive circuit layer of adjacent two that electrically conducts, and one of them insulation in outermost layer conducting wire layer surface is situated between Matter layer includes multiple second and is open, and this second to be open and form weld pad for exposing the conductive circuit layer, wherein, n is natural number, n≧2。

8. the ultrathin circuit board of fine rule road is had as claimed in claim 7, it is characterised in that the weld pad surface is formed with gold pad.

9. the ultrathin circuit board of fine rule road is had as claimed in claim 8, it is characterised in that the thickness of the insulating medium layer is situated between In 5 μm -15 μm.

10. the ultrathin circuit board of fine rule road is had as claimed in claim 9, it is characterised in that the thickness of the conductive circuit layer is situated between In 2 μm -12 μm.