CN110784987A - Free grounding film, circuit board and preparation method of free grounding film - Google Patents
Free grounding film, circuit board and preparation method of free grounding film Download PDFInfo
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- CN110784987A CN110784987A CN201811424086.5A CN201811424086A CN110784987A CN 110784987 A CN110784987 A CN 110784987A CN 201811424086 A CN201811424086 A CN 201811424086A CN 110784987 A CN110784987 A CN 110784987A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0213—Electrical arrangements not otherwise provided for
- H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
- H05K1/0218—Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/07—Electric details
- H05K2201/0707—Shielding
- H05K2201/0715—Shielding provided by an outer layer of PCB
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- Microelectronics & Electronic Packaging (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
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Abstract
The invention relates to the field of electronics, and discloses a free grounding film, a circuit board and a preparation method of the free grounding film, wherein the free grounding film comprises a first conductor layer, a first insulating layer, a second conductor layer and a glue film layer which are sequentially stacked, the bending property of the free grounding film is increased by arranging the first insulating layer, the first conductor layer is in close contact with the second conductor layer through a pore of the first insulating layer, so that the peeling strength between the first conductor layer and the second conductor layer is higher, and the electric connection between the first conductor layer and the second conductor layer is realized through the pore of the first insulating layer; when the free grounding film is used for grounding the printed circuit board, the electromagnetic shielding film is arranged on the printed circuit board and comprises a shielding layer and a second insulating layer, and when the free grounding film is pressed with the electromagnetic shielding film, the first conductor particles pierce the adhesive film layer and the second insulating layer and are electrically connected with the shielding layer, so that interference charges are led out, and the interference sources formed by accumulation of the interference charges are avoided.
Description
Technical Field
The invention relates to the field of electronics, in particular to a free grounding film, a circuit board and a preparation method of the free grounding film.
Background
With the rapid development of the electronic industry, electronic products are further miniaturized, light-weighted and densely assembled, and the development of flexible circuit boards is greatly promoted, so that the integration of element devices and wire connection is realized. The flexible circuit board can be widely applied to industries such as mobile phones, liquid crystal display, communication, aerospace and the like.
Under the push of the international market, the functional flexible printed circuit board is dominant in the flexible printed circuit board market, and an important index for evaluating the performance of the functional flexible printed circuit board is Electromagnetic Shielding (EMI Shielding for short). With the integration of the functions of communication equipment such as mobile phones, the internal components thereof are rapidly high-frequency and high-speed. For example: besides the original audio transmission function, the camera function has become a necessary function, and WLAN (Wireless Local Area network), GPS (Global Positioning System) and internet function have become popular, and the integration of the sensing component in the future makes the trend of rapid high-frequency and high-speed of the component unavoidable. Problems of electromagnetic interference inside and outside the device, signal attenuation during transmission, insertion loss, and jitter caused by high-frequency and high-speed driving are becoming serious.
At present, the circuit board is generally provided with an electromagnetic shielding film to reduce electromagnetic interference, while in the process of shielding electromagnetic waves, interference charges generated from the outside are accumulated on a shielding layer of the electromagnetic shielding film, thereby affecting signal transmission of the circuit board, and in order to lead out the interference charges, a free grounding film can be provided on the electromagnetic shielding film. The free grounding membrane that current circuit board was used commonly generally includes conductive layer and conductive adhesive layer, and the conductive layer passes through the conductive adhesive layer and switches on with the shielding layer contact of electromagnetic shield membrane, and then makes the interference electric charge of gathering on the shielding layer of electromagnetic shield membrane can derive via the free grounding membrane, but this kind of free grounding membrane's buckling nature is relatively poor, is not convenient for use.
Disclosure of Invention
The invention aims to provide a free grounding film, a circuit board and a preparation method of the free grounding film, which can enhance the bending property of the free grounding film on the premise of ensuring that interference charges are led out.
In order to solve the technical problem, the invention provides a free grounding membrane, which comprises a first conductor layer, a first insulating layer, a second conductor layer and a glue film layer, wherein the first conductor layer, the first insulating layer, the second conductor layer and the glue film layer are sequentially stacked, the first insulating layer is provided with a hole, the first conductor layer and the second conductor layer are mutually contacted through the hole to realize electric conduction, and one surface of the second conductor layer, which is close to the glue film layer, is provided with convex first conductor particles; when the free grounding film is used for grounding a printed circuit board, an electromagnetic shielding film is arranged on the printed circuit board and comprises a shielding layer and a second insulating layer, the second insulating layer is arranged on the shielding layer, the free grounding film is in press fit with the electromagnetic shielding film through the glue film layer, and the first conductor particles penetrate through the glue film layer and the second insulating layer and are electrically connected with the shielding layer.
Preferably, the first conductor particles comprise one or more of metal particles, carbon nanotube particles and ferrite particles, and the metal particles comprise single metal particles and/or alloy particles; the single metal particles are made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy particles are made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.
Preferably, the height of the first conductor particles is 35 μm to 100 μm.
Preferably, the first conductor layer has a thickness of 0.01 to 45 μm, the second conductor layer has a thickness of 0.01 to 45 μm, the first insulation layer has a thickness of 1 to 80 μm, and the adhesive film layer has a thickness of 0.1 to 80 μm.
Preferably, one surface of the second conductor layer, which is close to the adhesive film layer, is a flat surface or a non-flat surface.
Preferably, one surface of the second conductor layer, which is close to the adhesive film layer, includes a plurality of protrusions and a plurality of recesses, and the plurality of protrusions and the plurality of recesses are arranged at intervals.
Preferably, the adhesive layer comprises an adhesive layer containing conductive particles; or the adhesive film layer comprises an adhesion layer without conductive particles.
Preferably, the free grounding film further comprises an anti-oxidation layer, and the anti-oxidation layer is arranged on one surface of the first conductor layer, which is far away from the glue film layer.
Preferably, the free grounding film further comprises a peelable protective film layer, and the peelable protective film layer is arranged on one surface, away from the second conductor layer, of the adhesive film layer.
In order to solve the same technical problem, the invention further provides a circuit board, which comprises the electromagnetic shielding film, the printed circuit board and the free grounding film, wherein the electromagnetic shielding film is arranged on the printed circuit board, the electromagnetic shielding film comprises a shielding layer and a second insulating layer, the second insulating layer is arranged on the shielding layer, the free grounding film is pressed with the electromagnetic shielding film through the adhesive film layer, and the first conductor particles pierce the adhesive film layer and the second insulating layer and are electrically connected with the shielding layer.
As a preferred scheme, the electromagnetic shielding film further comprises an adhesive layer, the adhesive layer is arranged on the surface, away from the second insulating layer, of the shielding layer, the surface, close to the adhesive layer, of the shielding layer is provided with second conductor particles, and the second conductor particles penetrate through the adhesive layer and are electrically connected with the ground layer of the printed circuit board.
The invention provides a free grounding film and a circuit board, wherein the free grounding film comprises a first conductor layer, a first insulating layer, a second conductor layer and a glue film layer which are sequentially stacked, the first insulating layer is arranged between the first conductor layer and the second conductor layer so as to increase the bending property of the free grounding film, and meanwhile, the first conductor layer and the second conductor layer can be in close contact through the pores of the first insulating layer, so that the peeling strength between the first conductor layer and the second conductor layer is higher, and the electric connection between the first conductor layer and the second conductor layer is realized through the pores of the first insulating layer; in addition, through be equipped with the first conductor granule of convex on the one side that the second conductor layer is close to the glued membrane layer, when free ground membrane is used for the ground connection of printed wiring board, be equipped with electromagnetic shield membrane on printed wiring board, electromagnetic shield membrane includes shielding layer and second insulating layer, the second insulating layer is located on the shielding layer, when free ground membrane and electromagnetic shield membrane pressfitting, impale glued membrane layer and second insulating layer and be connected with the shielding layer electricity through first conductor granule to derive the interference electric charge of gathering on the electromagnetic shield membrane, avoided the accumulation of interference electric charge and formed the normal work that the interference source influences printed wiring board.
In order to solve the same technical problem, the invention also provides a preparation method of the free grounding film, which is suitable for preparing the free grounding film and comprises the following steps:
forming a first conductor layer;
forming a first insulating layer on the first conductor layer;
forming a second conductor layer on the first insulating layer;
forming first conductor particles in a convex shape on the second conductor layer;
forming a glue film layer on one surface of the second conductor layer, on which the first conductor particles are formed;
wherein the first insulating layer has a pore, and the first conductor layer and the second conductor layer are in contact with each other through the pore to realize electric conduction; when the free grounding film is used for grounding a printed circuit board, an electromagnetic shielding film is arranged on the printed circuit board and comprises a shielding layer and a second insulating layer, the second insulating layer is arranged on the shielding layer, the free grounding film is in press fit with the electromagnetic shielding film through the glue film layer, and the first conductor particles penetrate through the glue film layer and the second insulating layer and are electrically connected with the shielding layer.
Preferably, the forming of the first conductor layer specifically includes:
forming an oxidation preventing layer on the carrier film;
forming a first conductor layer on the oxidation preventing layer; or the like, or, alternatively,
forming a first conductor layer on the surface of the strippable layer with the carrier;
forming an oxidation preventing layer on the first conductor layer;
peeling the peelable layer of the tape carrier.
Preferably, the forming a second conductor layer on the first insulating layer specifically includes:
forming a second conductor layer on the first insulating layer by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating.
Preferably, a glue film layer is formed on a surface of the second conductor layer on which the first conductor particles are formed, and specifically, the glue film layer includes:
coating a glue film layer on the release film;
pressing and transferring the adhesive film layer to one surface of the second conductor layer, wherein the surface is formed with the first conductor particles; or the like, or, alternatively,
and coating a glue film layer on one surface of the second conductor layer, on which the first conductor particles are formed.
The invention provides a method for preparing a free grounding film, which comprises the steps of firstly forming a first conductor layer, then, forming a first insulating layer on the first conductor layer, forming a second conductor layer on the first insulating layer, and then, forming first conductor particles in a convex shape on the second conductor layer, and finally forming an adhesive film layer on the surface of the second conductor layer on which the first conductor particles are formed, so that the prepared free grounding film comprises a first conductor layer, a first insulating layer, a second conductor layer and a glue film layer which are sequentially stacked, by disposing the first insulating layer between the first conductor layer and the second conductor layer, the bendability of the free grounding film is increased, meanwhile, the first conductor layer and the second conductor layer can be in close contact through the pores of the first insulating layer, thereby the peeling strength between the first conductor layer and the second conductor layer is relatively large, and the electric connection between the first conductor layer and the second conductor layer is realized through the pores of the first insulating layer; in addition, through be equipped with the first conductor granule of convex on the one side that the second conductor layer is close to the glued membrane layer, when free ground membrane is used for the ground connection of printed wiring board, be equipped with electromagnetic shield membrane on printed wiring board, electromagnetic shield membrane includes shielding layer and second insulating layer, the second insulating layer is located on the shielding layer, when free ground membrane and electromagnetic shield membrane pressfitting, impale glued membrane layer and second insulating layer and be connected with the shielding layer electricity through first conductor granule to derive the interference electric charge of gathering on the electromagnetic shield membrane, avoided the accumulation of interference electric charge and formed the normal work that the interference source influences printed wiring board.
Drawings
FIG. 1 is a schematic structural diagram of a free grounding film when one side of a second conductive layer is a flat surface according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a free grounding film when one side of a second conductive layer is an uneven surface according to an embodiment of the present invention;
FIG. 3 is a schematic view of another angle structure of the free grounding film when one side of the second conductive layer is a flat surface or a non-flat surface according to the embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a circuit board with a flat surface on one side of a second conductive layer according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of another embodiment of a circuit board in which one side of a second conductor layer is a flat surface according to an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of a circuit board with a non-planar surface on one side of a second conductive layer according to an embodiment of the present invention;
FIG. 7 is a schematic structural diagram of another embodiment of a circuit board in which one side of a second conductor layer is a non-planar surface according to an embodiment of the present invention;
FIG. 8 is a schematic flow chart of a method of preparing a free-grounding film in an embodiment of the present invention;
wherein, 1, a first conductor layer; 2. a glue film layer; 3. a first conductive particle; 4. an oxidation-resistant layer; 5. an electromagnetic shielding film; 51. a second insulating layer; 52. a shielding layer; 53. a glue layer; 6. a printed wiring board; 7. a second conductive particle; 8. a first insulating layer; 81. a pore; 9. a second conductor layer; 91. a convex portion; 92. a recessed portion.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
With reference to fig. 1 to 7, a free grounding film according to a preferred embodiment of the present invention includes a first conductor layer 1, a first insulating layer 8, a second conductor layer 9, and a glue film layer 2, where the first conductor layer 1, the first insulating layer 8, the second conductor layer 9, and the glue film layer 2 are sequentially stacked, a hole 81 is formed on the first insulating layer 8, the first conductor layer 1 and the second conductor layer 9 are in contact with each other through the hole 81 to achieve electrical conduction, and a convex first conductor particle 3 is disposed on one surface of the second conductor layer 9 close to the glue film layer 2; when the free grounding film is used for grounding the printed circuit board 6, the electromagnetic shielding film 5 is arranged on the printed circuit board 6, the electromagnetic shielding film 5 comprises a shielding layer 52 and a second insulating layer 51, the second insulating layer 51 is arranged on the shielding layer 52, the free grounding film is pressed with the electromagnetic shielding film 5 through the glue film layer 2, and the first conductor particles 3 penetrate through the glue film layer 2 and the second insulating layer 51 and are electrically connected with the shielding layer 52.
In the embodiment of the present invention, the first insulating layer 8 is disposed between the first conductor layer 1 and the second conductor layer 9 to increase the flexibility of the free grounding film, and at the same time, the first conductor layer 1 and the second conductor layer 9 can be in close contact through the pores 81 of the first insulating layer 8, so that the peel strength between the first conductor layer 1 and the second conductor layer 9 is large, and the electrical connection between the first conductor layer 1 and the second conductor layer 9 is realized through the pores 81 of the first insulating layer 8; in addition, when the free grounding film is used for grounding the printed circuit board 6 by arranging the convex first conductor particles 3 on the surface of the second conductor layer 9 close to the adhesive film layer 2, the electromagnetic shielding film 5 is arranged on the printed circuit board 6, the electromagnetic shielding film 5 comprises a shielding layer 52 and a second insulating layer 51, the second insulating layer 51 is arranged on the shielding layer 52, and when the free grounding film is laminated with the electromagnetic shielding film 5, the adhesive film layer 2 and the second insulating layer 51 are pierced through the first conductor particles 3 and are electrically connected with the shielding layer 52; when the printed circuit board 6 is applied to an electronic device, the free grounding film can be electrically connected with a shell of the electronic device, so that interference charges accumulated on the electromagnetic shielding film 5 can be led out through the free grounding film, the interference charges can be led out through the shell of the electronic device, and the grounding of the electromagnetic shielding film 5 is further ensured, so that the interference charges accumulated on the electromagnetic shielding film 5 are led out, and the interference sources formed by the accumulation of the interference charges are prevented from influencing the normal work of the printed circuit board 6.
In the present embodiment, the area of the pores 81 is preferably 0.01 μm
2-1mm
2The number of the pores 81 per square centimeter of the first insulating layer 8 is preferably set to 5 to 10
6And (4) respectively. By making the area of the pores 81 preferably 0.01 μm
2-1mm
2The number of the pores 81 per square centimeter of the first insulating layer 8 is preferably set to 5 to 10
6To ensure that the first insulating layer 8 has a sufficient number of the pores 81 per unit area to ensure that the first conductor layer 1 and the second conductor layer 9 are in contact with each other for electrical conduction.
In the embodiment of the present invention, the pores 81 may be regularly or irregularly distributed on the first insulating layer 8; wherein, the pores 81 are regularly distributed on the first insulating layer 8, which means that the pores 81 are uniformly distributed on the first insulating layer 8 in the same shape; the pores 81 are irregularly distributed on the first insulating layer 8, which means that the shapes of the pores 81 are different and are randomly distributed on the first insulating layer 8. Preferably, the shape of each aperture 81 is the same, and each aperture 81 is uniformly distributed on the first insulating layer 8. In addition, the aperture 81 may be a circular aperture 81, and may also be an aperture 81 of any other shape, and the drawings of the present invention only illustrate that the aperture 81 is a circular aperture 81, but the aperture 81 of any other shape is within the protection scope of the present invention.
In a specific implementation, the second conductor layer 9 may be formed first, and then the first conductor particles 3 may be formed on the second conductor layer 9 by another process. Of course, the second conductor layer 9 and the first conductor particles 3 may also be an integral structure formed by a one-time molding process.
Preferably, the height of the first conductor particles 3 is 35 μm to 100 μm, and the thickness of the second insulating layer 51 is preferably 1 μm to 20 μm. By providing the height of the first conductor particles 3 preferably in the range of 35 μm to 100 μm and the thickness of the glue film layer 22 preferably in the range of 0.1 μm to 80 μm, it is ensured that the first conductor particles 3 can penetrate through the glue film layer 22 and the second insulating layer 51 of the electromagnetic shielding film 5, thereby ensuring that the free-grounding film can conduct away the interfering charges accumulated on the electromagnetic shielding film 5. Further, the thickness of the first conductor layer 1 and the second conductor layer 9 is preferably 0.01 μm to 45 μm to ensure that the first conductor layer 1 and the second conductor layer 9 are not easily broken and have good flexibility.
The first conductor particles 3 may have a certain distance from the outer surface of the adhesive film layer 2, and may also contact the outer surface of the adhesive film layer 2 or extend out of the outer surface of the adhesive film layer 2. In addition, the outer surface of the adhesive film layer 2 may be a flat surface without undulation, or may be an uneven surface with gentle undulation. In addition, the surface of the second conductor layer 9 away from the adhesive film layer 2 may be a surface of any shape, for example, a flat surface, an uneven surface with a wavy shape, or other rough surface. The drawings of the present invention only illustrate the second conductor layer 9 as a flat surface on the side away from the adhesive film layer 2, but any other shape is within the scope of the present invention.
In the embodiment of the present invention, the first conductor particles 3 may include a plurality of first conductor particles 3, and the plurality of first conductor particles 3 may be regularly or irregularly distributed on a surface of the second conductor layer 9 close to the adhesive film layer 2; the plurality of first conductor particles 3 are regularly distributed on one surface of the second conductor layer 9 close to the adhesive film layer 2, that is, the plurality of first conductor particles 3 are the same in shape and are uniformly distributed on one surface of the second conductor layer 9 close to the adhesive film layer 2; the plurality of first conductor particles 3 irregularly distributed on the surface of the second conductor layer 9 close to the adhesive film layer 2 means that the plurality of first conductor particles 3 are irregularly distributed on the surface of the second conductor layer 9 close to the adhesive film layer 2 in different shapes. Preferably, the shapes of the first conductor particles 3 are the same, and the first conductor particles 3 are uniformly distributed on one surface of the second conductor layer 9 close to the adhesive film layer 2.
It should be noted that the shapes of the first conductive particles 3 in fig. 1, 2, 4 to 7 are merely exemplary, and the first conductive particles 3 may have other shapes such as clusters, ice-hanging shapes, stalactites, and dendrites due to differences in process means and parameters. In addition, the first conductive particles 3 in the embodiment of the present invention are not limited to the shapes shown in the drawings and described above, and any first conductive particles 3 having piercing and conductive functions are within the scope of the present invention.
Preferably, the material used for the glue film layer 2 is selected from the following materials: modified epoxy resins, acrylic resins, modified rubbers, and modified thermoplastic polyimides. It is understood that, in order to ensure that the first conductor layer 1 and the second conductor layer 9 have good electrical conductivity, the first conductor layer 1 and the second conductor layer 9 may respectively include one or more of a metal conductor layer, a carbon nanotube conductor layer, a ferrite conductor layer, and a graphene conductor layer. Wherein the metal conductor layer comprises a single metal conductor layer and/or an alloy conductor layer; the single metal conductor layer is made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy conductor layer is made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.
It should be noted that the first conductor layer 1, the first insulating layer 8, and the second conductor layer 9 of the present embodiment may be a single-layer structure or a multi-layer structure, respectively. When the first conductor layer 1 is a single layer or multiple layers, convex first conductor particles 3 may be disposed on one surface of each first conductor layer 1 close to the adhesive film layer 2; when the second conductive layer 9 is a plurality of layers, convex first conductive particles 3 may be further disposed on one surface of each second conductive layer 9 close to the adhesive film layer 2. Preferably, when the first conductor layer 1, the first insulating layer 8 and the second conductor layer 9 are respectively provided in plurality, three of the first conductor layer 1, the first insulating layer 8 and the second conductor layer 9 are sequentially arranged at intervals, for example, when the first conductor layer 1, the first insulating layer 8 and the second conductor layer 9 are respectively provided in 2, the arrangement order may be: one of the first conductive layers 1, one of the first insulating layers 8, one of the second conductive layers 9, another one of the first conductive layers 1, another one of the first insulating layers 8, another one of the second conductive layers 9, and so on, which will not be described herein again. In addition, the first conductor layer 1 and the second conductor layer 9 of the present embodiment may be provided in a grid shape, a bubble shape, etc. according to the actual production and application requirements.
Preferably, the first conductor particles 3 include one or more of metal particles, carbon nanotube particles, and ferrite particles, and the metal particles include single metal particles and/or alloy particles. Further, the single metal particles are made of any one material of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy particles are made of any two or more materials of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold. The first conductive particles 33 may be made of the same material as the conductive layer 1, or may be made of a different material.
As shown in fig. 1, fig. 2, and fig. 4 to fig. 7, one surface of the second conductor layer 9 close to the adhesive film layer 2 is a flat surface or a non-flat surface. The uneven surface of the second conductor layer 9 is a regular uneven surface or an irregular uneven surface. Specifically, when the uneven surface of the second conductor layer 9 is a regular uneven surface, the uneven surface is a structure in which the undulations vary periodically, and the amplitude of the undulations on the uneven surface and the intervals of the undulations are the same; when the uneven surface of the second conductor layer 9 is an irregular uneven surface, the uneven surface is a structure with non-periodic fluctuation, and the amplitude of the fluctuation and/or the interval of the fluctuation on the uneven surface are different.
As shown in fig. 2, 6 and 7, in order to make the free grounding film more easily pierce through the adhesive film layer 2 and the shielding layer 52 of the electromagnetic shielding film 5 during the laminating process, one surface of the second conductor layer 9 in the present embodiment, which is close to the adhesive film layer 2, includes a plurality of convex portions 91 and a plurality of concave portions 92, and the plurality of convex portions 91 and the plurality of concave portions 92 are disposed at intervals. By arranging a plurality of convex parts 91 and a plurality of concave parts 92 on one surface of the second conductor layer 9 close to the adhesive film layer 2 and arranging a plurality of convex parts 91 and a plurality of concave parts 92 at intervals, the second conductor layer 9 can more easily pierce through the adhesive film layer 2 and the shielding layer 52 of the electromagnetic shielding film 5 in the pressing process, so that the second conductor layer 9 can be ensured to be in contact with the shielding layer 52 of the electromagnetic shielding film 5; in addition, when the free grounding film is pressed with the electromagnetic shielding film 5, the glue substances forming the glue film layer 2 are extruded into the concave part 92 to increase the glue containing amount, so that the phenomenon that the free grounding film is separated from the electromagnetic shielding film 5 is not easy to occur, the problem that the free grounding film is separated from the electromagnetic shielding film due to insufficient glue containing amount of the existing electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film 5 is effectively ensured, so that the interference charges are led out; in addition, the plurality of protrusions 91 may have a certain distance from the outer surface of the adhesive film layer 2, and may also contact the outer surface of the adhesive film layer 2 or extend out of the outer surface of the adhesive film layer 2.
In the embodiment of the present invention, in order to further ensure the reliability of the grounding and improve the conductive efficiency, the distance between each of the convex portions 91 and the adjacent concave portions 92 is the same. By setting the distance between each convex part 91 and the adjacent concave part 92 to be the same, the convex parts 91 can uniformly pierce the adhesive film layer 2, thereby further ensuring that the second conductor layer 9 is in contact with the shielding layer 52 of the electromagnetic shielding film 5, and improving the conductive efficiency. Preferably, each of the convex portions 9112 has the same shape; each of the recesses 92 is identical in shape; wherein each of the protrusions 91 is of an axisymmetric structure; each of the recesses 92 has an axisymmetric structure; of course, each of the protrusions 91 may also have a non-axisymmetrical structure, and each of the recesses 92 may also have a non-axisymmetrical structure. Because the distance between each convex part 91 and the adjacent concave part 92 is the same, the shape of each convex part 91 is the same, and the shape of each concave part 92 is the same, the glue capacity of the surface of the second conductor layer 9 is uniform, the problem that the free grounding film and the electromagnetic shielding film are separated due to insufficient glue capacity of the existing electromagnetic shielding film is further avoided, the grounding of the electromagnetic shielding film 5 is effectively ensured, and the interference charges are led out.
In the embodiment of the present invention, in order to further ensure that the free grounding film is electrically connected to the shielding layer 52 of the electromagnetic shielding film 5, the adhesive layer 2 in the embodiment includes an adhesive layer containing conductive particles. The adhesive layer 2 comprises an adhesive layer containing conductive particles to improve the conductivity of the adhesive layer 2, thereby further ensuring that the free grounding film is electrically connected with the shielding layer 52 of the electromagnetic shielding film 5. Of course, the adhesive layer 2 may include an adhesive layer without conductive particles to reduce the eddy current loss of the circuit board with the free grounding film, thereby ensuring the integrity of transmission and improving the flexibility of the circuit board while improving the shielding performance.
The conductive particles may be conductive particles separated from each other, or may be large-particle conductive particles formed by aggregation; when the conductive particles are mutually separated conductive particles, the grounding conductivity of the adhesive film layer 2 can be further improved; and when the conductive particles are agglomerated large conductive particles, the piercing strength can be increased.
In the embodiment of the present invention, the free grounding film further includes an anti-oxidation layer 4, and the anti-oxidation layer 4 is disposed on a surface of the first conductor layer 1 away from the glue film layer 2. The thickness range, material and forming mode of the oxidation preventing layer 4 can be any one of the following conditions:
①, the thickness of the oxidation-proof layer 4 is 0.01-5 μm, preferably 0.1-1 μm, the oxidation-proof layer 44 is made of any one of metal material, ferrite, graphite, carbon nano tube, graphene and silver paste, the metal material is any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, gold and molybdenum, or the metal material is an alloy made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, gold and molybdenum, the oxidation-proof layer 4 can be formed by one or more composite processes of chemical plating, PVD, CVD, evaporation plating, sputtering plating and electroplating;
② the thickness of the oxidation-proof layer 4 is 0.1-5 μm, the oxidation-proof layer 4 is made of a mixture of glue and conductive particles, and the volume ratio of the conductive particles to the glue is 5-80%, the oxidation-proof layer 4 can be formed by coating and then curing.
In the embodiment of the present invention, in order to protect the free grounding film, the free grounding film in the embodiment further includes a peelable protective film layer, and the peelable protective film layer is disposed on a surface of the adhesive film layer 2 away from the second surface. The strippable protective film layer is arranged on the side, away from the second conductor layer 9, of the adhesive film layer 2 to protect the free grounding film, and can be stripped in use.
With reference to fig. 4 to 7, in order to solve the same technical problem, an embodiment of the present invention further provides a circuit board, including the electromagnetic shielding film 5, the printed circuit board 6, and the free grounding film, where the electromagnetic shielding film 5 is disposed on the printed circuit board 6, the electromagnetic shielding film 5 includes a shielding layer 52 and a second insulating layer 51, the second insulating layer 51 is disposed on the shielding layer 52, the free grounding film is pressed against the electromagnetic shielding film 5 through the adhesive film layer 2, and the first conductor particles 3 pierce through the adhesive film layer 2 and the second insulating layer 51 and are electrically connected to the shielding layer 52.
In the embodiment of the present invention, the free grounding film is pressed to the electromagnetic shielding film 5 through the adhesive film layer 2, and the first conductor particles 3 pierce the adhesive film layer 2 and the second insulating layer 51 and are electrically connected to the shielding layer 52; when the circuit board is applied to electronic equipment, the free grounding film can be electrically connected with the shell of the electronic equipment, so that interference charges of the electromagnetic shielding film 5 can be led out through the free grounding film, the interference charges can be led out through the shell of the electronic equipment, the interference charges in the shielding layer 52 of the electromagnetic shielding film 5 are led into the ground, and the interference charges are prevented from accumulating to form an interference source to influence the normal operation of the circuit board.
Preferably, the printed circuit board 6 is one of a flexible single-sided board, a flexible double-sided board, a flexible multilayer board, and a rigid-flex printed board.
Referring to fig. 4 to 7, in the embodiment of the present invention, in order to implement that the electromagnetic shielding film 5 is disposed on the printed circuit board 6, the electromagnetic shielding film 5 in the embodiment may further include a glue layer 53, where the glue layer 53 is disposed on a side of the shielding layer 52 away from the second insulating layer 51. Preferably, the adhesive layer 53 is a conductive adhesive layer 53, and the adhesive layer 53 is electrically connected to the ground layer of the printed wiring board 6. By electrically connecting the adhesive layer 53 to the ground layer of the printed wiring board 6, it is ensured that the shielding layer 52 is connected to the ground layer of the printed wiring board 6, and it is further ensured that the electromagnetic shielding film 5 is grounded and the interference charges are conducted out.
In order to realize the electrical connection between the shielding layer 52 and the ground layer of the printed circuit board 6, as shown in fig. 5 and 7, in this embodiment, the second conductive particles 7 are disposed on a surface of the shielding layer 52 close to the adhesive layer 53, and the second conductive particles 7 pierce the adhesive layer 53 and are electrically connected to the ground layer of the printed circuit board 6. The second conductive particles 7 are arranged on one side of the shielding layer 52 close to the adhesive layer 53, so that when the electromagnetic shielding film 5 and the printed circuit board 6 are pressed together, the second conductive particles 7 can pierce the adhesive layer 53, thereby further achieving grounding of the shielding layer 52, wherein the second conductive particles 7 may be the same as or different from the first conductive particles 3; in addition, one surface of the shielding layer 52 close to the adhesive layer 53 may be a flat surface or a non-flat surface, and preferably, one surface of the shielding layer 52 close to the adhesive layer 53 is a non-flat surface, so that the shielding layer 52 can pierce through the adhesive layer 53, thereby achieving grounding of the shielding layer 52, and it is only necessary that the shielding layer 52 can be electrically connected with the ground layer of the printed circuit board, which is not described herein in further detail.
Referring to fig. 8, in order to solve the same technical problem, an embodiment of the present invention further provides a method for manufacturing a free grounding film, which is suitable for manufacturing the free grounding film, and includes the following steps:
s11, forming a first conductive layer 1;
s12, forming a first insulating layer 8 on the first conductor layer 1;
s13, forming a second conductor layer 9 on the first insulating layer 8;
s14, forming the first conductor particles 3 in a convex shape on the second conductor layer 9;
s15, forming a glue film layer 2 on the surface of the second conductor layer 9 on which the first conductor particles 3 are formed;
wherein, the first insulating layer 8 has a pore 81, and the first conductor layer 1 and the second conductor layer 9 are in contact with each other through the pore 81 to realize electric conduction; when the free grounding film is used for grounding the printed circuit board 6, the electromagnetic shielding film 5 is arranged on the printed circuit board 6, the electromagnetic shielding film 5 comprises a shielding layer 52 and a second insulating layer 51, the second insulating layer 51 is arranged on the shielding layer 52, the free grounding film is pressed with the electromagnetic shielding film 5 through the glue film layer 2, and the first conductor particles 3 penetrate through the glue film layer 2 and the second insulating layer 51 and are electrically connected with the shielding layer 52.
In the embodiment of the present invention, the first insulating layer 8 may be made to have the pores 81 that enable electrical conduction between the first conductor layer 1 and the second conductor layer 9 by:
firstly, processing a PPS, PEN or polyimide film and the like by laser processing or die cutting to form a first insulating layer 8 with pores 81, wherein the thickness is preferably 1-80 μm, and then forming a first conductor layer 1 and/or a second conductor layer 9 on the surface of the first insulating layer 8 with pores 81 by sputtering and the like, so that when the first conductor layer 1 and/or the second conductor layer 9 are formed, part of materials for preparing the first conductor layer 1 and/or the second conductor layer 9 extend into the pores 81 to realize metal filling of the pores 81, and therefore the first conductor layer 1 and the second conductor layer 9 can be in contact with each other through the pores 81 to realize electric conduction; alternatively, the pores 81 are directly treated by electroless plating or the like so that the inner surfaces of the pores 81 form a metal layer, thereby enabling the first conductor layer 1 and the second conductor layer 9 to be electrically conducted through the pores 81 in contact with each other. Further, since the first insulating layer 8 is made of an elastic material such as PPS, PEN, or a polyimide film, the flexibility of the free-ground film can be improved by providing the first insulating layer 8 having elasticity.
In the present embodiment, the area of the pores 81 is preferably 0.01 μm
2-1mm
2The number of the pores 81 per square centimeter of the first insulating layer 8 is preferably set to 5 to 10
6And (4) respectively. By making the area of the pores 81 preferably 0.01 μm
2-1mm
2The number of the pores 81 per square centimeter of the first insulating layer 8 is preferably set to 5 to 10
6To ensure that the first insulating layer 8 has a sufficient number of the pores 81 per unit area to ensure that the first conductor layer 1 and the second conductor layer 9 are in contact with each other for electrical conduction.
In the embodiment of the present invention, the pores 81 may be regularly or irregularly distributed on the first insulating layer 8; wherein, the pores 81 are regularly distributed on the first insulating layer 8, which means that the pores 81 are uniformly distributed on the first insulating layer 8 in the same shape; the pores 81 are irregularly distributed on the first insulating layer 8, which means that the shapes of the pores 81 are different and are randomly distributed on the first insulating layer 8. Preferably, the shape of each aperture 81 is the same, and each aperture 81 is uniformly distributed on the first insulating layer 8. In addition, the aperture 81 may be a circular aperture 81, and may also be an aperture 81 of any other shape, and the drawings of the present invention only illustrate that the aperture 81 is a circular aperture 81, but the aperture 81 of any other shape is within the protection scope of the present invention.
In the embodiment of the present invention, one surface of the second conductor layer 9 close to the adhesive film layer 2 is a flat surface or a non-flat surface. The uneven surface of the second conductor layer 9 is a regular uneven surface or an irregular uneven surface. Specifically, when the uneven surface of the second conductor layer 9 is a regular uneven surface, the uneven surface is a structure in which the undulations vary periodically, and the amplitude of the undulations on the uneven surface and the intervals of the undulations are the same; when the uneven surface of the second conductor layer 9 is an irregular uneven surface, the uneven surface is a structure with non-periodic fluctuation, and the amplitude of the fluctuation and/or the interval of the fluctuation on the uneven surface are different.
As shown in fig. 2, 6 and 7, in order to make the free grounding film more easily pierce through the adhesive film layer 2 and the shielding layer 52 of the electromagnetic shielding film 5 during the laminating process, one surface of the second conductor layer 9 in the present embodiment, which is close to the adhesive film layer 2, includes a plurality of convex portions 91 and a plurality of concave portions 92, and the plurality of convex portions 91 and the plurality of concave portions 92 are disposed at intervals. By arranging a plurality of convex parts 91 and a plurality of concave parts 92 on one surface of the second conductor layer 9 close to the adhesive film layer 2 and arranging a plurality of convex parts 91 and a plurality of concave parts 92 at intervals, the second conductor layer 9 can more easily pierce through the adhesive film layer 2 and the shielding layer 52 of the electromagnetic shielding film 5 in the pressing process, so that the second conductor layer 9 can be ensured to be in contact with the shielding layer 52 of the electromagnetic shielding film 5; in addition, when the free grounding film is pressed with the electromagnetic shielding film 5, the glue substances forming the glue film layer 2 are extruded into the concave part 92 to increase the glue containing amount, so that the phenomenon that the free grounding film is separated from the electromagnetic shielding film 5 is not easy to occur, the problem that the free grounding film is separated from the electromagnetic shielding film due to insufficient glue containing amount of the existing electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film 5 is effectively ensured, so that the interference charges are led out; in addition, the plurality of protrusions 91 may have a certain distance from the outer surface of the adhesive film layer 2, and may also contact the outer surface of the adhesive film layer 2 or extend out of the outer surface of the adhesive film layer 2.
In the embodiment of the present invention, in order to further ensure the reliability of the grounding and improve the conductive efficiency, the distance between each of the convex portions 91 and the adjacent concave portions 92 is the same. By setting the distance between each convex part 91 and the adjacent concave part 92 to be the same, the convex parts 91 can uniformly pierce the adhesive film layer 2, thereby further ensuring that the second conductor layer 9 is in contact with the shielding layer 52 of the electromagnetic shielding film 5, and improving the conductive efficiency. Preferably, each of the convex portions 9112 has the same shape; each of the recesses 92 is identical in shape; wherein each of the protrusions 91 is of an axisymmetric structure; each of the recesses 92 has an axisymmetric structure; of course, each of the protrusions 91 may also have a non-axisymmetrical structure, and each of the recesses 92 may also have a non-axisymmetrical structure. Because the distance between each convex part 91 and the adjacent concave part 92 is the same, the shape of each convex part 91 is the same, and the shape of each concave part 92 is the same, so that the glue capacity of the surface of the second conductor layer 9 is uniform, the problem that the free grounding film is separated from the electromagnetic shielding film 5 due to insufficient glue capacity of the existing electromagnetic shielding film is further avoided, the grounding of the electromagnetic shielding film 5 is effectively ensured, and the interference charges are led out.
In this embodiment of the present invention, the step S11 specifically includes:
s21, forming an oxidation preventing layer 4 on the carrier film;
s22, forming a first conductor layer 1 on the oxidation preventing layer 4; wherein, the first conductor layer 1 can be formed on the oxidation preventing layer 4 by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and mixed plating; or the like, or, alternatively,
s31, forming a first conductor layer 1 on the surface of the peelable layer with the carrier; wherein the first conductor layer 1 may be formed on the surface of the releasable layer with carrier by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating;
s32, forming an oxidation preventing layer 4 on the first conductor layer 1;
s33, peeling the peelable layer of the tape carrier.
Specifically, the thickness range, material and formation mode of the oxidation preventing layer 4 may be any one of the following cases:
①, the thickness of the oxidation preventing layer 4 is 0.01-5 μm, preferably 0.1-1 μm, the oxidation preventing layer 4 is made of any one of metal material, ferrite, graphite, carbon nano tube, graphene and silver paste, the metal material is any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, gold and molybdenum, or the metal material is an alloy made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, gold and molybdenum, the oxidation preventing layer 4 can be formed by one or more composite processes of chemical plating, PVD, CVD, evaporation plating, sputtering plating and electroplating;
② the thickness of the oxidation-proof layer 4 is 0.1-5 μm, the oxidation-proof layer 4 is made of a mixture of glue and conductive particles, and the volume ratio of the conductive particles to the glue is 5-80%, the oxidation-proof layer 4 can be formed by coating and then curing.
In this embodiment of the present invention, the step S13 specifically includes:
the second conductor layer 9 is formed on the first insulating layer 8 by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating.
In this embodiment of the present invention, the step S14 specifically includes:
the convex first conductor particles 3 are formed on the second conductor layer 9 by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and hybrid plating.
In this embodiment of the present invention, the step S15 specifically includes:
s41, coating the adhesive film layer 2 on the release film;
s42, transferring the adhesive film layer 2 onto the second conductor layer 9 with the first conductor particles 3 thereon; or the like, or, alternatively,
s51, the adhesive film layer 2 is coated on the surface of the second conductor layer 9 on which the first conductor particles 3 are formed.
To sum up, the embodiment of the present invention provides a free grounding film, a circuit board and a method for manufacturing the free grounding film, wherein the free grounding film includes a first conductor layer 1, a first insulating layer 8, a second conductor layer 9 and a glue film layer 2 which are sequentially stacked, the first insulating layer 8 is disposed between the first conductor layer 1 and the second conductor layer 9 to increase the flexibility of the free grounding film, and meanwhile, the first conductor layer 1 and the second conductor layer 9 can be in close contact through a pore 81 of the first insulating layer 8, so that the peeling strength between the first conductor layer 1 and the second conductor layer 9 is relatively large, and the first conductor layer 1 and the second conductor layer 9 are electrically connected through the pore 81 of the first insulating layer 8; in addition, when the free grounding film is used for grounding the printed circuit board 6 by arranging the convex first conductor particles 3 on the surface of the second conductor layer 9 close to the adhesive film layer 2, the electromagnetic shielding film 5 is arranged on the printed circuit board 6, the electromagnetic shielding film 5 comprises a shielding layer 52 and a second insulating layer 51, the second insulating layer 51 is arranged on the shielding layer 52, and when the free grounding film is laminated with the electromagnetic shielding film 5, the adhesive film layer 2 and the second insulating layer 51 are pierced through the first conductor particles 3 and are electrically connected with the shielding layer 52; when the printed circuit board 6 is applied to an electronic device, the free grounding film can be electrically connected with a shell of the electronic device, so that interference charges accumulated on the electromagnetic shielding film 5 can be led out through the free grounding film, the interference charges can be led out through the shell of the electronic device, and the grounding of the electromagnetic shielding film 5 is further ensured, so that the interference charges accumulated on the electromagnetic shielding film 5 are led out, and the interference sources formed by the accumulation of the interference charges are prevented from influencing the normal work of the printed circuit board 6.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.
Claims (15)
1. A free grounding membrane is characterized by comprising a first conductor layer, a first insulating layer, a second conductor layer and a glue film layer, wherein the first conductor layer, the first insulating layer, the second conductor layer and the glue film layer are sequentially stacked, a hole is formed in the first insulating layer, the first conductor layer and the second conductor layer are mutually contacted through the hole to realize electric conduction, and convex first conductor particles are arranged on one surface, close to the glue film layer, of the second conductor layer; when the free grounding film is used for grounding a printed circuit board, an electromagnetic shielding film is arranged on the printed circuit board and comprises a shielding layer and a second insulating layer, the second insulating layer is arranged on the shielding layer, the free grounding film is in press fit with the electromagnetic shielding film through the glue film layer, and the first conductor particles penetrate through the glue film layer and the second insulating layer and are electrically connected with the shielding layer.
2. The free grounding film of claim 1, wherein the first conductor particles comprise one or more of metal particles, carbon nanotube particles, and ferrite particles, the metal particles comprising single metal particles and/or alloy particles; the single metal particles are made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy particles are made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.
3. The free grounding film of claim 1, wherein the first conductor particles have a height of 35 μm to 100 μm.
4. The free grounding film of claim 1, wherein the first conductor layer has a thickness of 0.01 μ ι η to 45 μ ι η, the second conductor layer has a thickness of 0.01 μ ι η to 45 μ ι η, the first insulating layer has a thickness of 1 μ ι η to 80 μ ι η, and the glue film layer has a thickness of 0.1 μ ι η to 80 μ ι η.
5. The free grounding film of claim 1, wherein the side of the second conductor layer adjacent to the glue film layer is a flat surface or a non-flat surface.
6. The free grounding film of claim 5, wherein a surface of the second conductor layer adjacent to the adhesive film layer comprises a plurality of protrusions and a plurality of recesses, and the plurality of protrusions and the plurality of recesses are arranged at intervals.
7. The free grounding film of any one of claims 1 to 6, wherein the glue layer comprises an adhesive layer containing conductive particles; or the adhesive film layer comprises an adhesion layer without conductive particles.
8. The free grounding film of any one of claims 1 to 6, wherein the free grounding film further comprises an oxidation preventing layer, and the oxidation preventing layer is disposed on a surface of the first conductor layer away from the glue film layer.
9. The free grounding film of any of claims 1 to 6, further comprising a peelable protective film layer disposed on a side of the glue film layer remote from the second conductor layer.
10. A circuit board comprising the electromagnetic shielding film, the printed circuit board and the free grounding film of any one of claims 1 to 9, wherein the electromagnetic shielding film is disposed on the printed circuit board, the electromagnetic shielding film comprises a shielding layer and a second insulating layer, the second insulating layer is disposed on the shielding layer, the free grounding film is laminated with the electromagnetic shielding film through the adhesive film layer, and the first conductor particles pierce the adhesive film layer and the second insulating layer and are electrically connected to the shielding layer.
11. The circuit board of claim 10, wherein the electromagnetic shielding film further comprises an adhesive layer, the adhesive layer is disposed on a surface of the shielding layer away from the second insulating layer, and second conductive particles are disposed on a surface of the shielding layer close to the adhesive layer, and the second conductive particles pierce the adhesive layer and are electrically connected to a ground layer of the printed circuit board.
12. A method for preparing a free-grounding film, which is suitable for preparing the free-grounding film of any one of claims 1 to 9, comprising the steps of:
forming a first conductor layer;
forming a first insulating layer on the first conductor layer;
forming a second conductor layer on the first insulating layer;
forming first conductor particles in a convex shape on the second conductor layer;
forming a glue film layer on one surface of the second conductor layer, on which the first conductor particles are formed;
wherein the first insulating layer has a pore, and the first conductor layer and the second conductor layer are in contact with each other through the pore to realize electric conduction; when the free grounding film is used for grounding a printed circuit board, an electromagnetic shielding film is arranged on the printed circuit board and comprises a shielding layer and a second insulating layer, the second insulating layer is arranged on the shielding layer, the free grounding film is in press fit with the electromagnetic shielding film through the glue film layer, and the first conductor particles penetrate through the glue film layer and the second insulating layer and are electrically connected with the shielding layer.
13. The method for preparing a free-grounding film as claimed in claim 12, wherein the forming of the first conductor layer specifically comprises:
forming an oxidation preventing layer on the carrier film;
forming a first conductor layer on the oxidation preventing layer; or the like, or, alternatively,
forming a first conductor layer on the surface of the strippable layer with the carrier;
forming an oxidation preventing layer on the first conductor layer;
peeling the peelable layer of the tape carrier.
14. The method for preparing a free grounding film according to claim 12, wherein forming a second conductor layer on the first insulating layer specifically comprises:
forming a second conductor layer on the first insulating layer by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating.
15. A method for preparing a free-grounding film as claimed in any one of claims 12 to 14, wherein a glue film layer is formed on the side of the second conductor layer on which the first conductor particles are formed, specifically:
coating a glue film layer on the release film;
pressing and transferring the adhesive film layer to one surface of the second conductor layer, wherein the surface is formed with the first conductor particles; or the like, or, alternatively,
and coating a glue film layer on one surface of the second conductor layer, on which the first conductor particles are formed.
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|---|---|---|---|
| CN201811424086.5A CN110784987A (en) | 2018-11-26 | 2018-11-26 | Free grounding film, circuit board and preparation method of free grounding film |
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| CN201811424086.5A CN110784987A (en) | 2018-11-26 | 2018-11-26 | Free grounding film, circuit board and preparation method of free grounding film |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112867253A (en) * | 2020-12-31 | 2021-05-28 | 福莱盈电子股份有限公司 | Preparation method of electromagnetic shielding film and preparation method of circuit board structure |
| CN117580351A (en) * | 2023-11-17 | 2024-02-20 | 广州方邦电子股份有限公司 | Electromagnetic shielding film and circuit board |
-
2018
- 2018-11-26 CN CN201811424086.5A patent/CN110784987A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112867253A (en) * | 2020-12-31 | 2021-05-28 | 福莱盈电子股份有限公司 | Preparation method of electromagnetic shielding film and preparation method of circuit board structure |
| CN117580351A (en) * | 2023-11-17 | 2024-02-20 | 广州方邦电子股份有限公司 | Electromagnetic shielding film and circuit board |
| CN117580351B (en) * | 2023-11-17 | 2024-05-03 | 广州方邦电子股份有限公司 | Electromagnetic shielding film and circuit board |
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