CN110691501A - Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film - Google Patents
Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film Download PDFInfo
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- CN110691501A CN110691501A CN201810743743.6A CN201810743743A CN110691501A CN 110691501 A CN110691501 A CN 110691501A CN 201810743743 A CN201810743743 A CN 201810743743A CN 110691501 A CN110691501 A CN 110691501A
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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
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/0084—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single continuous metallic layer on an electrically insulating supporting structure, e.g. metal foil, film, plating coating, electro-deposition, vapour-deposition
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
- B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
- B32B3/30—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B33/00—Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/20—Adhesives in the form of films or foils characterised by their carriers
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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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
- B32B2307/212—Electromagnetic interference shielding
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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
Abstract
The invention relates to the technical field of electronics, and discloses an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding film, wherein the electromagnetic shielding film comprises a shielding layer and an adhesive film layer, the adhesive film layer is arranged on the shielding layer, one surface of the shielding layer, which is close to the adhesive film layer, is a non-flat surface with the same undulation degree, and convex conductor particles are arranged on one surface of the shielding layer, which is close to the adhesive film layer; so that the conductor particles can pierce the adhesive film layer and be connected with the stratum of the circuit board when the electromagnetic shielding film is laminated with the circuit board, the grounding failure caused by pulling apart of conductive particles of the adhesive film layer when the adhesive film layer of the existing electromagnetic shielding film expands at high temperature is avoided, and the grounding connection of the shielding layer and the circuit board is ensured.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding 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, an electromagnetic shielding film commonly used for an existing circuit board comprises a shielding layer and an adhesive film layer containing conductive particles, wherein the shielding layer is grounded and conducted with a ground layer of the circuit board through the adhesive film layer containing the conductive particles, but the adhesive film layer is easy to expand and the conductive particles of the adhesive film layer are pulled apart under high-temperature pressing, so that the shielding layer cannot be grounded and conducted with the ground layer of the circuit board through the adhesive film layer, and the grounding reliability is affected.
Disclosure of Invention
The embodiment of the invention aims to provide an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding film, which can effectively avoid grounding failure caused by pulling apart of conductive particles of an adhesive film layer when the adhesive film layer of the conventional electromagnetic shielding film expands at high temperature so as to ensure that the electromagnetic shielding film is grounded and interference charges are led out.
In order to solve the technical problem, an embodiment of the present invention provides an electromagnetic shielding film, including a shielding layer and a glue film layer, where one surface of the shielding layer close to the glue film layer is a non-flat surface with the same undulation degree, and convex conductor particles are arranged on one surface of the shielding layer close to the glue film layer; the adhesive film layer is arranged on the shielding layer.
Preferably, one surface of the shielding 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 distance between each convex part and the adjacent concave part is the same.
Preferably, each of the projections has the same shape; the shape of each concave part is the same.
Preferably, each convex part is of an axisymmetric structure; each depressed part is the axisymmetrical structure.
Preferably, the thickness of the shielding layer is 0.1-45 μm, and the thickness of the adhesive film layer is 1-80 μm.
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 electromagnetic shielding film further comprises a protective film layer, and the protective film layer is arranged on one surface of the shielding layer far away from the adhesive film layer.
In order to solve the same technical problem, an embodiment of the present invention further provides a circuit board, including a circuit board body and the electromagnetic shielding film, wherein the electromagnetic shielding film is laminated with the circuit board body through the adhesive film layer; the conductor particles penetrate through the glue film layer and are electrically connected with the ground layer of the circuit board body.
The embodiment of the invention provides an electromagnetic shielding film and a circuit board, wherein the electromagnetic shielding film comprises a shielding layer and an adhesive film layer, the adhesive film layer is arranged on the shielding layer, one surface of the shielding layer, which is close to the adhesive film layer, is a non-flat surface with the same undulation degree, and convex conductor particles are arranged on one surface of the shielding layer, which is close to the adhesive film layer, so that the conductor particles can pierce the adhesive film layer and are connected with the stratum of the circuit board when the electromagnetic shielding film is laminated with the circuit board, thereby ensuring the stratum connection of the shielding layer and the circuit board, avoiding the ground failure caused by the fact that the conductive particles of the adhesive film layer are pulled apart when the adhesive film layer of the existing electromagnetic shielding film expands at high temperature, and further ensuring the; in addition, as the surface of the shielding layer close to the adhesive film layer is a non-flat surface with the same undulation degree, more conductor particles on the shielding layer can pierce the adhesive film layer, the grounding reliability is ensured, and the conductive efficiency is improved; in addition, because the one side that is close to the glued membrane layer at the shielding layer is the uneven surface that the degree of fluctuation is the same, consequently when electromagnetic shielding membrane and circuit board pressfitting, constitute gluey class material of glued membrane layer and be extruded in this uneven surface's the sunk position to increase the volume of holding glue, thereby be difficult to the board phenomenon of exploding appears, avoided current electromagnetic shielding membrane because hold glue volume not enough lead to the problem that the board was exploded to high temperature, and then guaranteed electromagnetic shielding membrane ground connection effectively, thereby will disturb the electric charge and derive.
In order to solve the same technical problem, an embodiment of the present invention further provides a method for preparing an electromagnetic shielding film, including the following steps:
forming a shielding layer; one surface of the shielding layer is a non-flat surface with the same undulation degree;
forming conductor particles on the uneven surface with the same undulation degree of the shielding layer;
and forming a film adhesive layer on one surface of the shielding layer on which the conductor particles are formed.
Preferably, the method for preparing the electromagnetic shielding film further comprises:
and forming a protective film layer on one surface of the shielding layer far away from the adhesive film layer.
Preferably, the forming of the shielding layer specifically includes:
forming a protective film layer on the carrier film;
forming a shielding layer on the protective film layer; or the like, or, alternatively,
forming a shielding layer on the surface of the strippable layer with the carrier;
forming a protective film layer on the shielding layer;
peeling the peelable layer of the tape carrier.
Preferably, the step of forming a shielding layer on the protective film layer/the peelable layer with the carrier specifically includes:
forming a shielding layer on a flat surface or a non-flat surface of the peelable layer of the protective film layer/tape carrier;
performing surface treatment on the shielding layer through 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,
a barrier layer is formed on the non-planar surface of the peelable layer of the protective film layer/tape carrier.
As a preferable scheme, the conductor particles are formed on the non-flat surface with the same undulation degree of the shielding layer, specifically:
and forming conductor particles on the uneven surface with the same undulation degree of the shielding layer by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and mixed plating.
Preferably, a glue film layer is formed on the surface of the shielding layer on which the 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 shielding layer, on which the conductor particles are formed; or the like, or, alternatively,
and coating a glue film layer on one surface of the shielding layer on which the conductor particles are formed.
The embodiment of the invention provides a preparation method of an electromagnetic shielding film, which comprises the steps of firstly, forming a shielding layer, then forming conductor particles on a non-flat surface with the same undulation degree of the shielding layer, and then forming an adhesive film layer on one surface of the shielding layer, on which the conductor particles are formed, so that the prepared electromagnetic shielding film is arranged on the shielding layer by arranging the adhesive film layer on the shielding layer, one surface of the shielding layer, which is close to the adhesive film layer, is a non-flat surface with the same undulation degree, and the surface of the shielding layer, which is close to the adhesive film layer, is provided with convex conductor particles, so that the conductor particles can pierce the adhesive film layer and are connected with the stratum of a circuit board when the electromagnetic shielding film is laminated with the circuit board, the conductive particles of the adhesive film layer are pulled apart to cause grounding failure when the adhesive film layer of the existing; in addition, as the surface of the shielding layer close to the adhesive film layer is a non-flat surface with the same undulation degree, more conductor particles on the shielding layer can pierce the adhesive film layer, the grounding reliability is ensured, and the conductive efficiency is improved; in addition, because the one side that is close to the glued membrane layer at the shielding layer is the uneven surface that the degree of fluctuation is the same, consequently when electromagnetic shielding membrane and circuit board pressfitting, constitute gluey class material of glued membrane layer and be extruded in this uneven surface's the sunk position to increase the volume of holding glue, thereby be difficult to the board phenomenon of exploding appears, avoided current electromagnetic shielding membrane because hold glue volume not enough lead to the problem that the board was exploded to high temperature, and then guaranteed electromagnetic shielding membrane ground connection effectively, thereby will disturb the electric charge and derive.
Drawings
Fig. 1 is a schematic structural view of an electromagnetic shielding film in an embodiment of the present invention;
fig. 2 is a schematic structural view of another embodiment of an electromagnetic shielding film in an example of the present invention;
FIG. 3 is a schematic structural diagram of a circuit board in an embodiment of the present invention;
fig. 4 is a schematic flow chart of a method for manufacturing an electro-magnetic shielding film in an embodiment of the present invention;
wherein, 1, a shielding layer; 11. a convex portion; 12. a recessed portion; 2. a glue film layer; 3. a conductive particle; 5. a protective film layer; 6. the circuit board body.
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.
Referring to fig. 1, an electromagnetic shielding film according to a preferred embodiment of the present invention includes a shielding layer 1 and a glue film layer 2, wherein one surface of the shielding layer 1 close to the glue film layer 2 is a non-flat surface with the same waviness, and convex conductor particles 3 are disposed on one surface of the shielding layer 1 close to the glue film layer 2; the adhesive film layer 2 is arranged on the shielding layer 1.
In the embodiment of the invention, the adhesive film layer 2 is arranged on the shielding layer 1, one surface of the shielding layer 1 close to the adhesive film layer 2 is a non-flat surface with the same undulation degree, and the surface of the shielding layer 1 close to the adhesive film layer 2 is provided with the convex conductor particles 3, so that the conductor particles 3 can pierce through the adhesive film layer 2 and are connected with the stratum of the circuit board when the electromagnetic shielding film is laminated with the circuit board, thereby ensuring the connection between the shielding layer 1 and the stratum of the circuit board, avoiding the grounding failure caused by the pulling of the conductive particles of the adhesive film layer 2 when the adhesive film layer 2 of the existing electromagnetic shielding film expands at high temperature, and ensuring the connection between the electromagnetic shielding film and the stratum of the circuit; in addition, as the surface of the shielding layer 1 close to the adhesive film layer 2 is a non-flat surface with the same undulation degree, more conductor particles 3 on the shielding layer 1 can pierce the adhesive film layer 2, the grounding reliability is ensured, and the conductive efficiency is improved; in addition, because the one side that is close to glue film layer 2 at shielding layer 1 is the uneven surface that the degree of fluctuation is the same, consequently when electromagnetic shielding membrane and circuit board pressfitting, constitute glue class material of glue film layer 2 and be extruded in this uneven surface's the sunk position to increase the volume of glue holding, thereby be difficult to the board phenomenon of exploding appears, avoided current electromagnetic shielding membrane because the volume of glue holding is not enough to lead to the problem that the board explodes of high temperature, and then guaranteed electromagnetic shielding membrane ground connection effectively, thereby will disturb the electric charge and derive.
In the embodiment of the present invention, the uneven surface of the shielding layer 1 is a regular uneven surface or an irregular uneven surface. Specifically, when the uneven surface of the shielding layer 1 is a regular uneven surface, the uneven surface is a structure with periodic fluctuation, and the amplitude of the fluctuation and the interval of the fluctuation on the uneven surface are the same; when the uneven surface of the shielding layer 1 is an irregular uneven surface, the uneven surface is a structure with non-periodic fluctuation, and the amplitude and/or interval of the fluctuation on the uneven surface are different.
In a specific implementation, the shielding layer 1 may be formed first, and then the conductive particles 3 may be formed on the shielding layer 1 through another process. Of course, the shielding layer 1 and the conductive particles 3 may also be an integral structure formed by a one-step molding process.
Preferably, the conductor particles 3 may be spaced 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.
The surface of the shielding layer 1 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 figure of the present invention only illustrates that the side of the shielding layer 1 away from the adhesive film layer 2 is a flat surface, but any other shape is within the protection scope of the present invention.
It should be noted that the shapes of the conductive particles 3 in fig. 1 to 3 are merely exemplary, and the conductive particles 3 may be in other shapes such as clusters, ice-hanging shapes, stalactites, and dendrites due to differences in process means and parameters. The conductive particle 3 in the present invention is not limited to the shape shown in the drawings, and any conductive particle 3 having piercing and conductive functions is within the scope of the present invention.
With reference to fig. 1 to 3, in order to make the shielding layer 1 pierce the adhesive film layer 2 more easily during the lamination process, a surface of the shielding layer 1 close to the adhesive film layer 2 in this embodiment includes a plurality of protrusions 11 and a plurality of recesses 12, and the plurality of protrusions 11 and the plurality of recesses 12 are disposed at intervals. The plurality of convex parts 11 and the plurality of concave parts 12 are arranged on one surface, close to the glue film layer 2, of the shielding layer 1, the plurality of convex parts 11 and the plurality of concave parts 12 are arranged at intervals, and the conductor particles 3 are distributed on the convex parts 11 in a concentrated mode, so that the shielding layer 1 can pierce the glue film layer 2 more easily in the laminating process, and the reliability of connection between the shielding layer 1 and the ground layer of the circuit board is ensured; in addition, when the electromagnetic shielding film is laminated with the circuit board, the glue substances forming the glue film layer 2 are extruded into the concave part 12 to increase the glue containing amount, so that the board explosion phenomenon is not easy to occur, the problem that the board is exploded at high temperature due to insufficient glue containing amount of the existing electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film is effectively ensured, so that the interference charges are led out. Preferably, the conductor particles 3 are intensively distributed on the convex parts 11, so that the shielding layer 1 can pierce the adhesive film layer 2 more easily in the pressing process, thereby realizing grounding and improving the quality of electromagnetic shielding. In addition, the plurality of protrusions 11 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, the conductor particles 3 may include a plurality of conductor particles 3, and the plurality of conductor particles 3 may be regularly or irregularly distributed on a surface of the shielding layer 1 close to the adhesive film layer 2; the plurality of conductor particles 3 are regularly distributed on one surface of the shielding layer 1 close to the adhesive film layer 2, that is, the plurality of conductor particles 3 are in the same shape and are uniformly distributed on one surface of the shielding layer 1 close to the adhesive film layer 2; the plurality of conductor particles 3 irregularly distributed on the surface of the shielding layer 1 close to the adhesive film layer 2 means that the plurality of conductor particles 3 are irregularly distributed on the surface of the shielding layer 1 close to the adhesive film layer 2. Preferably, the shape of the plurality of conductor particles 3 is the same, and the plurality of conductor particles 3 are uniformly distributed on one surface of the shielding layer 1 close to the adhesive film layer 2.
Referring to fig. 1, in order to make more conductive particles 3 on the shielding layer 1 penetrate through the adhesive layer 2, the distance between each protrusion 11 and the adjacent recess 12 is the same in this embodiment. The distance between each convex part 11 and the adjacent concave part 12 is set to be the same, so that the conductor particles 3 on the convex parts 11 can uniformly pierce the adhesive film layer 2, and it is beneficial for more conductor particles 3 on the shielding layer 1 to pierce the adhesive film layer 2, so as to further ensure the reliability of grounding and improve the conductive efficiency. Preferably, each of the projections 11 is identical in shape; each of the recesses 12 is identical in shape; wherein each of the protrusions 11 is of an axisymmetric structure; each of the concave portions 12 is of an axisymmetric structure; of course, each of the protrusions 11 may also have a non-axisymmetric structure, and each of the recesses 12 may also have a non-axisymmetric structure. Because the distance between each convex part 11 and the adjacent concave part 12 is the same, the shape of each convex part 11 is the same, and the shape of each concave part 12 is the same, the glue capacity of the surface of the shielding layer 1 is uniform, the board explosion is further avoided, the grounding of the electromagnetic shielding film is further ensured, and the interference charges are led out.
In the embodiment of the invention, the height of the conductor particles 3 is 0.1-30 μm, the thickness of the shielding layer 1 is 0.1-45 μm, and the thickness of the adhesive film layer 2 is 1-80 μm. The glue film layer 2 is made of the following materials: modified epoxy resins, acrylic resins, modified rubbers, and modified thermoplastic polyimides. It can be understood that, in order to ensure that the shielding layer 1 has good electrical conductivity, the shielding layer 1 includes one or more of a metal shielding layer, a carbon nanotube shielding layer, a ferrite shielding layer and a graphene shielding layer. Wherein the metal shielding layer comprises a single metal shielding layer and/or an alloy shielding layer; the single metal shielding layer is made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy shielding layer is made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold. As shown in fig. 1, the thickness of the shielding layer 1 is a distance D1 between a highest point of a surface of the shielding layer 1 away from the adhesive film layer 2 and a lowest point of a surface of the shielding layer 1 close to the adhesive film layer 2, and the thickness of the adhesive film layer 2 is a distance D2 between the highest point and the lowest point of the adhesive film layer 2.
Preferably, the undulation degree of the side of the shielding layer 1 close to the adhesive film layer 2 (i.e. the distance between the highest point and the lowest point of the side of the shielding layer 1 close to the adhesive film layer 2) is 0.1 μm to 30 μm, and the undulation degree of the side of the shielding layer 1 close to the adhesive film layer 2 is set within the above range, so that the piercing function of the shielding layer 1 can be enhanced, thereby ensuring that the interference charges in the shielding layer 1 are smoothly introduced into the ground, and further avoiding the accumulation of the interference charges to form an interference source.
Preferably, the thickness of the adhesive film layer 2, the sum of the undulation degree of the shielding layer 1 close to the adhesive film layer 2 and the height of the conductor particles 3 satisfy a proportional relationship of 0.5-2, so as to ensure sufficient piercing strength and glue holding capacity, which is specifically embodied as follows: on one hand, the phenomenon that the fluctuation degree of the thickness of the glue film layer 2 relative to the surface, close to the glue film layer 2, of the shielding layer 1 and the sum of the heights of the conductor particles 3 is too small to cause insufficient glue capacity to cause plate explosion is prevented, and on the other hand, the fluctuation degree of the surface, close to the glue film layer 2, of the shielding layer 1 and the sum of the heights of the conductor particles 3 is too small to cause insufficient piercing strength to cause grounding failure is prevented.
In the present embodiment, the conductor particles 3 include one or more of metal particles, carbon nanotube particles, and ferrite particles. Further, the metal particles include 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. The conductive particles 3 may be the same as or different from the material of the shielding layer 1.
In the embodiment of the present invention, in order to further ensure the connection between the electromagnetic shielding film and the ground layer of the circuit board, the adhesive layer 2 in this embodiment includes an adhesive layer containing conductive particles. The adhesive film layer 2 comprises an adhesive layer containing conductive particles, so that the conductive capability of the adhesive film layer 2 is improved, and the ground connection of the electromagnetic shielding film and the circuit board is further ensured. 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 electromagnetic shielding film, so as to ensure the integrity of transmission and improve 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.
Referring to fig. 2, the electromagnetic shielding film of the present embodiment further includes a protection film layer 5, and the protection film layer 5 is disposed on a surface of the shielding layer 1 away from the adhesive film layer 2. The protective film layer 5 has an isolation effect, so that the shielding effectiveness of the shielding layer 1 is ensured; in addition, the protective film layer 5 also has a protective effect to ensure that the shielding layer 1 is not scratched or damaged in the using process, so that the high shielding effectiveness of the shielding layer 1 is maintained. The protective film layer 5 comprises a PPS film layer, a PEN film layer, a polyester film layer, a polyimide film layer, a film layer formed after epoxy resin ink is cured, a film layer formed after polyurethane ink is cured, a film layer formed after modified acrylic resin is cured or a film layer formed after polyimide resin is cured. A carrier film may also be disposed on a surface of the protective film layer 5 away from the shielding layer 1.
The shielding layer 1 of the present embodiment may have a single-layer structure or a multi-layer structure. The shielding layer 1 and the adhesive film layer 2 may be provided in plurality. Preferably, when the shielding layer 1 and the adhesive film layer 2 are respectively a plurality of, the shielding layer 1 and the adhesive film layer 2 are sequentially arranged at intervals, for example, when the shielding layer 1 and the adhesive film layer 2 are respectively 2, the arrangement sequence may be: one shielding layer 1, one adhesive film layer 2, another shielding layer 1, another adhesive film layer 2, and so on, which will not be described herein. When the shielding layer 1 is a plurality of layers, each layer of the shielding layer 1 may be provided with convex conductor particles 3 or without convex conductor particles 3 on the surface close to the adhesive film layer 2. In addition, the shielding layer 1 of the present embodiment may be provided in a grid shape, a foam shape, etc. according to the requirements of actual production and application.
Referring to fig. 3, in order to solve the same technical problem, an embodiment of the present invention further provides a circuit board, including a circuit board body 6 and the electromagnetic shielding film, wherein the electromagnetic shielding film is pressed with the circuit board body 6 through the adhesive film layer 2; the conductor particles 3 pierce the adhesive film layer 2 and are electrically connected with the ground layer of the circuit board body 6.
In the embodiment of the invention, when the electromagnetic shielding film is pressed on the circuit board body 6, the conductor particles 3 can pierce the adhesive film layer 2 and are connected with the ground layer of the circuit board body 6, so that the ground connection between the shielding layer 1 and the circuit board body 6 is ensured, interference charges in the shielding layer 1 are led into the ground, and the influence of interference sources formed by accumulation of the interference charges on the normal operation of the circuit board is avoided.
Preferably, the circuit board body 6 is one of a flexible single-sided board, a flexible double-sided board, a flexible multilayer board and a flex-rigid board.
Referring to fig. 4, in order to solve the same technical problem, an embodiment of the present invention further provides a method for manufacturing an electromagnetic shielding film, including the following steps:
s11, forming a shielding layer 1; one surface of the shielding layer 1 is a non-flat surface with the same undulation degree;
s12, forming conductor particles 3 on the uneven surface of the shielding layer 1 with the same undulation degree;
s13, forming a film layer 2 on the surface of the shield layer 1 on which the conductive particles 3 are formed.
In step S12, the conductor particles 3 may be formed on the uneven surface of the shielding layer 1 having the same waviness 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 step S13, the adhesive film layer 2 may be formed on the surface of the shielding layer 1 on which the conductive particles 3 are formed by directly applying the adhesive film layer 2 on the surface of the shielding layer 1 on which the conductive particles 3 are formed; the method can also be characterized in that a glue film layer 2 is coated on a release film, and then the glue film layer 2 is transferred to the surface of the shielding layer 1 on which the conductor particles 3 are formed in a pressing mode, so that the glue film layer 2 is formed on the surface of the shielding layer 1 on which the conductor particles 3 are formed.
With reference to fig. 1 to 3, one surface of the shielding layer 1 close to the glue film layer 2 includes a plurality of protrusions 11 and a plurality of recesses 12, the plurality of protrusions 11 and the plurality of recesses 12 are disposed at intervals, and the conductor particles 3 are distributed on the protrusions 11 in a concentrated manner.
With reference to fig. 1 to 3, in order to make the shielding layer 1 pierce the adhesive film layer 2 more easily in the laminating process, a surface of the shielding layer 1 close to the adhesive film layer 2 in this embodiment includes a plurality of protrusions 11 and a plurality of recesses 12, the plurality of protrusions 11 and the plurality of recesses 12 are arranged at intervals, and the conductor particles 3 are distributed on the protrusions 11 in a concentrated manner. By arranging a plurality of convex parts 11 and a plurality of concave parts 12 on one surface of the shielding layer 1 close to the adhesive film layer 2, and arranging the plurality of convex parts 11 and the plurality of concave parts 12 at intervals, the conductor particles 3 are intensively distributed on the convex parts 11, so that the shielding layer 1 can pierce the adhesive film layer 2 more easily in the laminating process, and the grounding reliability of the shielding layer 1 is ensured; in addition, when the electromagnetic shielding film is laminated with the circuit board, the glue substances forming the glue film layer 2 are extruded into the concave part 12 to increase the glue containing amount, so that the board explosion phenomenon is not easy to occur, the problem that the board is exploded due to insufficient glue containing amount at high temperature of the existing electromagnetic shielding film is avoided, the grounding of the electromagnetic shielding film is ensured, and the interference charges are led out.
Referring to fig. 1, in order to make more conductive particles 3 on the shielding layer 1 penetrate through the adhesive layer 2, the distance between each protrusion 11 and the adjacent recess 12 is the same in this embodiment. The distance between each convex part 11 and the adjacent concave part 12 is set to be the same, so that the conductor particles 3 on the convex parts 11 can uniformly pierce the adhesive film layer 2, and it is beneficial for more conductor particles 3 on the shielding layer 1 to pierce the adhesive film layer 2, so as to further ensure the reliability of grounding and improve the conductive efficiency. Preferably, each of the projections 11 is identical in shape; each of the recesses 12 is identical in shape; wherein each of the protrusions 11 is of an axisymmetric structure; each of the concave portions 12 is of an axisymmetric structure; of course, each of the protrusions 11 may also have a non-axisymmetric structure, and each of the recesses 12 may also have a non-axisymmetric structure. Because the distance between each convex part 11 and the adjacent concave part 12 is the same, the shape of each convex part 11 is the same, and the shape of each concave part 12 is the same, the glue capacity of the surface of the shielding layer 1 is uniform, the board explosion is further avoided, the grounding of the electromagnetic shielding film is further ensured, and the interference charges are led out.
In step S11, the forming of the shielding layer 1 may specifically form the shielding layer 1 in the following two ways:
mode (1):
s21, forming a protective film layer 5 on the carrier film;
s22, forming a shielding layer 1 on the protective film layer 5; the shielding layer 1 may be formed on the protective film layer 5 by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating.
Mode (2):
s31, forming a shielding layer 1 on the surface of the strippable layer with the carrier; the shielding layer 1 may be formed on the surface of the peelable layer of the tape 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 a protective film layer 5 on the shielding layer 1;
s33, peeling the peelable layer of the tape carrier.
When the shielding layer 1 is formed in the manner (1), one surface of the shielding layer 1 can be made to be a non-flat surface with the same degree of undulation by the following two manners:
the method i:
s41, forming a shielding layer 1 on the flat surface or the non-flat surface of the protective film layer 5;
s42, performing surface treatment on the shielding layer 1 through one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and mixed plating;
when the mode i is adopted, the surface treatment of the shielding layer 1 may be performed by one or more of the above-described physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and hybrid plating, regardless of the surface state of the protective film layer 5, so that the waviness of the treated surface of the shielding layer 1 is the same.
Mode ii:
s51, forming a shielding layer 1 on the uneven surface of the protective film layer 5; wherein the undulation degree of the non-flat surface of the protective film layer 5 is the same.
When the mode ii is adopted, the size and the proportion of the filler may be controlled to control the undulation degree of the protective film layer 5 when the protective film layer 5 is prepared so that the undulation degree of the non-flat surface of the protective film layer 5 is the same, and then the shielding layer 1 is formed on the non-flat surface of the protective film layer 5.
When the shielding layer 1 is formed in the manner (2), one surface of the shielding layer 1 can be made to be a non-flat surface with the same degree of undulation by the following two manners:
mode iii:
s61, forming a shielding layer 1 on the flat surface or the non-flat surface of the peelable layer with a carrier;
s62, performing surface treatment on the shielding layer 1 by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating.
When the mode iii is employed, the surface treatment of the shield layer 1 may be performed by one or more of the above-described physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and hybrid plating so that the waviness of the treated surface of the shield layer 1 is the same regardless of the surface state of the peelable layer of the tape carrier.
In the way iv:
s71, forming a shielding layer 1 on the non-flat surface of the strippable layer with the carrier; wherein the non-flat surfaces of the peelable layers of the tape carrier have the same waviness.
When the mode iv is adopted, the waviness of the surface of the peelable layer with the carrier can be controlled so that the waviness of the side of the peelable layer of the shielding layer 1 close to the tape carrier is the same when the shielding film is formed on the uneven surface of the peelable layer with the carrier.
To sum up, the embodiment of the invention provides an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding film, wherein the electromagnetic shielding film comprises a shielding layer 1 and an adhesive film layer 2, the adhesive film layer is arranged on the shielding layer, one surface of the shielding layer 1, which is close to the adhesive film layer 2, is a non-flat surface with the same undulation degree, and one surface of the shielding layer 1, which is close to the adhesive film layer 2, is provided with convex conductor particles 3, so that the conductor particles 3 can pierce the adhesive film layer 2 and are connected with the stratum of the circuit board when the electromagnetic shielding film is laminated with the circuit board, thereby ensuring the stratum connection of the shielding layer 1 and the circuit board, avoiding the conductive particles of the adhesive film layer 2 from being pulled apart to cause grounding failure when the adhesive film layer 2 of the existing electromagnetic shielding film expands at high temperature, and ensuring; in addition, as the surface of the shielding layer 1 close to the adhesive film layer 2 is a non-flat surface with the same undulation degree, more conductor particles 3 on the shielding layer 1 can pierce the adhesive film layer 2, the grounding reliability is ensured, and the conductive efficiency is improved; in addition, because the one side that is close to glue film layer 2 at shielding layer 1 is the uneven surface that the degree of fluctuation is the same, consequently when electromagnetic shielding membrane and circuit board pressfitting, constitute glue class material of glue film layer 2 and be extruded in this uneven surface's the sunk position to increase the volume of glue holding, thereby be difficult to the board phenomenon of exploding appears, avoided current electromagnetic shielding membrane because the volume of glue holding is not enough to lead to the problem that the board explodes of high temperature, and then guaranteed electromagnetic shielding membrane ground connection effectively, thereby will disturb the electric charge and derive.
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. The electromagnetic shielding film is characterized by comprising a shielding layer and a glue film layer, wherein one surface of the shielding layer, which is close to the glue film layer, is a non-flat surface with the same undulation degree, and convex conductor particles are arranged on one surface of the shielding layer, which is close to the glue film layer; the adhesive film layer is arranged on the shielding layer.
2. The electromagnetic shielding film according to claim 1, wherein a surface of the shielding layer adjacent to the adhesive film layer includes a plurality of convex portions and a plurality of concave portions, and the plurality of convex portions and the plurality of concave portions are disposed at intervals.
3. The electro-magnetic shielding film of claim 2, wherein each of the convex portions has the same distance from the adjacent concave portions.
4. The electro-magnetic shielding film of claim 2, wherein each of the protrusions has the same shape; the shape of each concave part is the same.
5. The electromagnetic shielding film according to claim 2, wherein each of the protrusions has an axisymmetric structure; each depressed part is the axisymmetrical structure.
6. The electro-magnetic shielding film of any one of claims 1-5, wherein the shielding layer has a thickness of 0.1 μm to 45 μm, and the adhesive film layer has a thickness of 1 μm to 80 μm.
7. The electromagnetic shielding film according to any one of claims 1 to 5, wherein the adhesive layer comprises an adhesive layer containing conductive particles; or the adhesive film layer comprises an adhesion layer without conductive particles.
8. The electromagnetic shielding film according to any one of claims 1 to 5, further comprising a protective film layer disposed on a side of the shielding layer away from the adhesive film layer.
9. A circuit board, comprising a circuit board body and the electromagnetic shielding film according to any one of claims 1 to 8, wherein the electromagnetic shielding film is laminated with the circuit board body through the adhesive film layer; the conductor particles penetrate through the glue film layer and are electrically connected with the ground layer of the circuit board body.
10. The preparation method of the electromagnetic shielding film is characterized by comprising the following steps of:
forming a shielding layer; one surface of the shielding layer is a non-flat surface with the same undulation degree;
forming conductor particles on the uneven surface with the same undulation degree of the shielding layer;
and forming a film adhesive layer on one surface of the shielding layer on which the conductor particles are formed.
11. The method of manufacturing an electro-magnetic shielding film according to claim 10, further comprising:
and forming a protective film layer on one surface of the shielding layer far away from the adhesive film layer.
12. The method for preparing an electromagnetic shielding film according to claim 10, wherein the forming of the shielding layer specifically comprises:
forming a protective film layer on the carrier film;
forming a shielding layer on the protective film layer; or the like, or, alternatively,
forming a shielding layer on the surface of the strippable layer with the carrier;
forming a protective film layer on the shielding layer;
peeling the peelable layer of the tape carrier.
13. The method of manufacturing an electromagnetic shielding film according to claim 12, wherein forming a shielding layer on the protective film layer/the peelable layer of the tape carrier specifically comprises:
forming a shielding layer on a flat surface or a non-flat surface of the peelable layer of the protective film layer/tape carrier;
performing surface treatment on the shielding layer through 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,
a barrier layer is formed on the non-planar surface of the peelable layer of the protective film layer/tape carrier.
14. The method for preparing an electro-magnetic shielding film according to any one of claims 10 to 13, wherein the conductive particles are formed on the uneven surface of the shielding layer having the same waviness, specifically:
and forming conductor particles on the uneven surface with the same undulation degree of the shielding layer by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and mixed plating.
15. The method for preparing an electro-magnetic shielding film according to any one of claims 10 to 13, wherein a glue film layer is formed on a surface of the shielding layer on which the conductive 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 shielding layer, on which the conductor particles are formed; or the like, or, alternatively,
and coating a glue film layer on one surface of the shielding layer on which the conductor particles are formed.
Priority Applications (1)
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| CN201810743743.6A CN110691501A (en) | 2018-07-06 | 2018-07-06 | Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810743743.6A CN110691501A (en) | 2018-07-06 | 2018-07-06 | Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film |
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| CN201810743743.6A Pending CN110691501A (en) | 2018-07-06 | 2018-07-06 | Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film |
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