KR20230025164A - EMI shielding materials for shield can, EMI shielding type circuit module comprising the same and Electronic device comprising the same - Google Patents

Abstract

An electromagnetic shielding sheet is provided. The electromagnetic shielding sheet for shield cans according to an embodiment of the present invention comprises: an electromagnetic shielding unit which is an electrically conductive fiber web layer having a first surface and a second surface facing each other; an electrically conductive adhesive unit composed of an electrically conductive adhesive layer formed on the first surface of the electrically conductive fiber web layer with a predetermined thickness, and an electrically conductive adhesive connected to the electrically conductive adhesive layer and placed on the entirety or part of pores of the electrically conductive fiber web layer; an insulating adhesive unit including an insulating adhesive layer formed on the second surface of the electrically conductive fiber web layer with a predetermined thickness; and an insulating heat dissipation unit formed on the insulating adhesive unit. Accordingly, the electromagnetic shielding sheet can block the emission of electromagnetic waves, to the outside, generated from components such as a driver chip in an electronic device to protect users, and prevent malfunctions of other components in the device or other electronic devices. Additionally, it is possible to prevent malfunctions of the driver chip by blocking electromagnetic waves applied to the device from the outside. In addition, due to excellent compressibility, the electromagnetic shielding sheet can be mounted without changing in the thickness of an electromagnetic shielding material even when there is a tolerance on a mounting area and the tolerance is large, and at the same time, can be pressed to meet the internal specifications of an original design of the electronic device, to be suitable for compact and lightweight electronic devices. Due to the excellent compressibility, the electromagnetic shielding sheet can compensate for thickness tolerances and at the same time, show improved electromagnetic shielding performance when compressed, and accordingly, can be widely used in electronic devices requiring excellent electromagnetic shielding performance and implemented to be light, thin, and small.

Description

Electromagnetic wave shielding sheet for shield can, electromagnetic wave shielding type circuit module including the same, and electronic device having the same

The present invention relates to an electromagnetic wave shielding sheet, and more particularly, to an electromagnetic wave shielding sheet for a shield can, an electromagnetic wave shielding type circuit module including the same, and an electronic device including the same.

Recent electronic devices are equipped with various elements, most of which are mounted on printed circuit boards, and these elements are electromagnetic interference (EMI) generated by internal or external interference sources in the electronic device, or generated by the device. As it is sensitive to heat, it has become a problem inducing malfunction of electronic devices due to electromagnetic waves and/or heat.

In recent years, in order to shield electromagnetic waves emitted from various elements disposed inside electronic equipment, a structure for shielding noise such as electromagnetic waves has been sought by surrounding elements with a shield can made of a metal plate. However, high-temperature heat emitted from various elements is trapped inside the shield-can and cannot be effectively released. To solve this problem, an opening is formed in a part of the shield-can to form a heat transfer passage, and a heat sink and a heat pipe are installed on the top of the shield-can. A noise shielding and heat dissipation structure with TIM interposed has been sought in order to provide various heat dissipation structures, such as those, or to improve heat transfer at the interface between the bracket and the shield cat disposed on the top of the shield can.

However, in such a noise shielding and heat dissipation structure, it is difficult to achieve a sufficient effect to allow electromagnetic waves to pass through the opening or to transfer heat inside the shield can through the bracket. and heat dissipation structures were introduced.

The electromagnetic wave shielding member adopts a structure in which an adhesive layer is disposed on one side or both sides of a substrate, which is a fibrous web, to increase adhesion at the interface between the shield can and/or bracket, and to have flexibility and compression characteristics, but the adhesion is weakened by moisture. After being attached on the shield can, as the adhesive layer continuously permeates into the pores inside the fiber web, there is a problem that the thickness deviation according to the position and the resulting problem of interface floating and deterioration of adhesiveness become more severe over time. In addition, for smooth heat transfer, a heat dissipation material such as TIM is treated to have a predetermined thickness on one side of the electromagnetic wave shielding member. Such a heat dissipation material can collect moisture, so the weakening of the insulating properties due to the collected moisture reduces the insulation of the TIM. There is a problem of deterioration of destruction and electromagnetic shielding performance.

Accordingly, there is an urgent need to develop an electromagnetic wave shielding member that minimizes changes in adhesive force and electromagnetic wave shielding performance over time.

Republic of Korea Patent Publication No. 10-0209962

The present invention has been made to solve the above-described problems, and protects users by blocking external emission of electromagnetic waves generated from a driving chip included in an electronic device, prevents malfunction of other parts or other devices in the device, and It is an object of the present invention to provide an electromagnetic wave shielding sheet for a shield can capable of preventing malfunction of a driving chip by blocking electromagnetic waves applied to a device from a device, an electromagnetic wave shielding type circuit module including the same, and an electronic device.

In addition, the present invention is an electromagnetic wave shielding sheet for a shield can having excellent performance retention in a use environment by preventing fluctuations in adhesive strength and electromagnetic wave shielding performance even in a use environment with high moisture or maintained in a compressed state for a long time while having excellent compressibility, including the same Another object is to provide an electromagnetic shielding type circuit module and an electronic device.

In order to solve the above problems, the present invention is an electromagnetic wave shielding part, which is an electrically conductive fibrous web layer having opposing first and second surfaces, and a layer formed on the first surface of the electrically conductive fibrous web layer to a predetermined thickness. An electrically conductive adhesive layer and an electrically conductive adhesive portion made of an electrically conductive adhesive disposed in all or part of the pores of the electrically conductive fibrous web layer following the electrically conductive adhesive layer, and having a predetermined thickness on the second surface of the electrically conductive fibrous web layer. An electromagnetic wave shielding sheet for a shield-can comprising an insulating adhesive portion including an insulating adhesive layer formed of and an insulating heat radiation portion formed on the insulating adhesive portion.

According to an embodiment of the present invention, the electromagnetic wave shielding sheet for the shield-can may have at least one opening having a predetermined area in a region corresponding to an element disposed inside the shield-can.

In addition, the electrically conductive fibrous web layer may have a thickness of 5 to 50 μm and a basis weight of 5 to 100 g/m 2 .

In addition, the electrically conductive fibrous web layer may include electrically conductive composite fibers in which an electrically conductive layer is coated on an outer surface of the fiber.

In addition, the electrically conductive composite fibers may have a diameter of 0.2 to 10 μm, and the thickness of the electrically conductive layer may be 0.1 to 2 μm.

In addition, the electrically conductive layer may be formed of at least one metal selected from the group consisting of aluminum, nickel, copper, silver, gold, chromium, platinum, titanium alloy, and stainless steel, and at least one conductive polymer compound.

In addition, the electrically conductive fibrous web layer may have no pore size gradient in a thickness direction from the first surface to the second surface.

In addition, the electrically conductive adhesive may be disposed so as to fill 90% or more, for example, 95% or more of the total pore volume inside the electrically conductive fibrous web layer, or all of the pores.

In addition, the insulating adhesive part may further include an insulating adhesive disposed in pores in the electrically conductive fibrous web layer following the insulating adhesive layer, and the insulating adhesive and the electrically conductive adhesive may be disposed to entirely fill the pores in the electrically conductive fibrous web layer. can

In addition, the thickness of the electrically conductive adhesive layer may be 5 to 50 μm, the thickness of the insulating adhesive layer may be 7 to 15 μm, and the thickness of the insulating heat radiation portion may be 30 to 200 μm.

In addition, the insulating heat dissipation part may include at least one ceramic filler selected from the group consisting of alumina, yttria, zirconia, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and single crystal silicon.

In addition, an opening may be provided in a predetermined region of the electromagnetic wave shielding sheet so as not to block the movement of heat generated from the device and radiated upward of the shield-can.

In addition, the insulation resistance in the thickness direction may be 1.0 GΩ/□ or more, and the horizontal resistance of the electrically conductive adhesive portion may be 0.05 Ω/□ or less.

In addition, the horizontal thermal conductivity may be 3 W/m·K or more.

In addition, when compressing with a load of 1 kg f / mm 2 perpendicular to the plane direction, the thickness reduction rate based on the thickness before compression may be 20% or more.

In addition, the present invention includes a circuit board on which elements are mounted, a shield can having sidewalls surrounding at least the area of the circuit board on which the elements are mounted and having upper and lower portions open, and at least a predetermined opening in an area corresponding to the elements. And the electromagnetic wave shielding sheet for shield-can according to the present invention disposed on the upper side of the shield-can so that the opening corresponds to the open top of the shield-can, and disposed on the upper side of the shield-can so that one side is in contact with the electromagnetic wave shielding sheet for shield-can It provides an electromagnetic shielding type circuit module including a metal bracket to be.

In addition, the present invention provides an electronic device including the electromagnetic shielding type circuit module according to the present invention.

The electromagnetic wave shielding sheet for shield cans according to the present invention blocks external emission of electromagnetic waves generated from elements such as driving chips provided in electronic devices to protect users and prevent malfunctions of other parts in the device or other electronic devices. . In addition, malfunction of the driving chip may be prevented by blocking electromagnetic waves applied to the device from the outside. In addition, even if it is compressed during mounting, the change in adhesive force is minimized or prevented, so that the change over time in which the adhesive force is weakened can be prevented. Furthermore, it is possible to prevent changes over time due to moisture in the air by minimizing the deterioration of adhesiveness due to moisture in the air, insulation breakdown due to moisture collection by the electromagnetic wave shielding sheet, and fluctuations in electromagnetic wave shielding performance.

1 is an enlarged cross-sectional view of an electromagnetic wave shielding sheet according to an embodiment of the present invention;
2 is a schematic cross-sectional view of electrically conductive composite fibers included in the electrically conductive fibrous web layer of the electromagnetic wave shielding sheet according to one embodiment of the present invention;
3 is an enlarged cross-sectional view of an electromagnetic wave shielding sheet according to another embodiment of the present invention;
4 is a perspective view of an electromagnetic wave shielding sheet according to an embodiment of the present invention, and
5 is a cross-sectional view of an electromagnetic wave shielding type circuit module according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are added to the same or similar components throughout the specification.

Referring to FIGS. 1, 2 and 5, the electromagnetic wave shielding sheet 100 for a shield can according to an embodiment of the present invention is an electrically conductive fibrous web layer 110 having opposing first and second surfaces. An electromagnetic wave shield, an electrically conductive adhesive layer 120a having a predetermined thickness formed on the first surface of the electrically conductive fibrous web layer 110, and the electrically conductive fibrous web layer following the electrically conductive adhesive layer 120a An electrically conductive adhesive portion 120 made of an electrically conductive adhesive 120b disposed in all or part of the pores of (110) and an insulating adhesive layer formed to a predetermined thickness on the second surface of the electrically conductive fibrous web layer 110 It includes an insulating adhesive portion 130 including, and an insulating heat dissipation portion 140 formed on the insulating adhesive portion 130 .

The electromagnetic wave shielding part exhibits electromagnetic wave shielding performance, which is the main function of the electromagnetic wave shielding sheets 100 and 200, and serves to smoothly transfer the heat transmitted from the shield can 500 to the side of the metal bracket 600 as a secondary function. Includes an electrically conductive fiber web layer 110 to have compression characteristics against the pressure applied when assembling the shield can 500 and the metal bracket 600 for flexibility and adhesion and thickness control that can be adhered to the mounting surface without lifting. do. As the electrically conductive fibrous web layer 110, a fibrous web and implemented to have electrical conductivity can be used without limitation. For example, a conductive high molecular compound is a material of the fibrous web layer, or a material having electrical conductivity is known. It may be processed into a fibrous web. Preferably, the electrically conductive fibrous web layer 110 may be implemented by including electrically conductive composite fibers 111 in which the electrically conductive layer 111b is coated on the outer surface of the fiber 111a.

In addition, the electrically conductive fibrous web layer 110 has first and second surfaces facing each other, and the first and second surfaces may be a front surface and a back surface serving as main surfaces.

In addition, the electrically conductive fibrous web layer 110 has a three-dimensional network structure, and may have a plurality of pores connecting the first surface of the electrically conductive fibrous web layer 110 and the second surface opposite thereto. Through this, flexibility and compression characteristics can be expressed. The conductive composite fiber 111 may have a diameter of 0.2 to 10 μm, and the thickness of the conductive layer 111b covering the fiber 111a may be 0.1 to 2 μm. If the diameter of the electrically conductive composite fiber 111 is less than 0.2 μm, handling properties may deteriorate and manufacturing may not be easy, and if the diameter exceeds 10 μm, the compressibility and electromagnetic wave shielding performance of the electrically conductive fibrous web layer may decrease. There are concerns. In addition, when the thickness of the electrically conductive layer 111b is less than 0.1 μm, electromagnetic wave shielding performance may deteriorate, and when it exceeds 2.0 μm, shape deformation such as compression or bending may become difficult. Cracks and peeling may occur in the layer 111b, which may degrade electromagnetic wave shielding performance.

The fiber 111a may be used without limitation if it is a material that can be manufactured and maintained in a conventional fiber shape. As non-limiting examples thereof, polyurethane, polystyrene, polyvinylalchol, polymethyl methacrylate, polylactic acid, polyethyleneoxide, poly Polyvinyl acetate, polyacrylic acid, polycaprolactone, polyacrylonitrile, polyvinylpyrrolidone, polyvinylchloride, polycarbonate, PC ( polycarbonate), polyetherimide, polyethersulfone, polybenzimidazol, polyethylene terephthalate, polybutylene terephthalate, and at least one selected from the group consisting of fluorine-based compounds. . In addition, the fluorine-based compound is polytetrafluoroethylene (PTFE)-based, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA)-based, tetrafluoroethylene-hexafluoropropylene copolymer (FEP)-based, Tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (EPE) system, tetrafluoroethylene-ethylene copolymer (ETFE) system, polychlorotrifluoroethylene (PCTFE) system, chlorotrifluoro It may include at least one compound selected from the group consisting of ethylene-ethylene copolymer (ECTFE)-based and polyvinylidene fluoride (PVDF)-based. Preferably, the fibers 111a may be spun by blending PVDF, which is a fluorine-based compound, with polyurethane in a spinning solution in order for the electrically conductive fibrous web layer 110 to exhibit improved compression characteristics, heat resistance, chemical resistance, and mechanical strength. there is.

In addition, the electrically conductive layer 111b is a layer that imparts electrical conductivity to the fiber web, and can be used without limitation if it is made of an electrically conductive material. For example, the electrically conductive layer 111b may be formed of at least one metal selected from the group consisting of aluminum, nickel, copper, silver, gold, chromium, platinum, titanium alloy, and stainless steel, and at least one conductive polymer compound. It may be, preferably made of metal.

Meanwhile, the conductive fibrous web layer 110 may be made of the conductive composite fibers 111, but is not limited thereto, and may further include non-conductive or very small fibers. In this case, the electrically conductive fibrous web layer 110 may be realized by mixing non-conductive or very small fibers with the aforementioned conductive composite fibers 111 without limitation in area. Alternatively, each of the electrically conductive fibrous web layers 110 may be provided to form a region with each other.

The thickness of the electrically conductive fibrous web layer 110 described above is appropriate in consideration of the thickness standard of the electromagnetic wave shielding type circuit module 1000, the desired electromagnetic wave shielding effect, and the thickness tolerance of the shield can 500 and the metal bracket 600. can be implemented as For example, the electrically conductive fibrous web layer 110 may have a thickness of 5 to 100 μm, for example, 5 to 50 μm, 5 to 30 μm, or 10 to 20 μm. If the thickness of the electrically conductive fibrous web layer 110 is less than 5 μm, the mechanical strength of the electrically conductive fibrous web layer may decrease, handling may become difficult, and manufacturing may not be easy. In addition, when the thickness exceeds 100 μm, there is a concern that flexibility, stretchability, and compressive properties may be deteriorated, and it may be difficult to form an electrically conductive layer on fibers located near the inner center of the fiber web layer.

In addition, the electrically conductive fibrous web layer 110 may have a basis weight of 5 to 100 g/m 2 , for example, 5 to 50 g/m 2 . If the basis weight is less than 5 g/m 2 , the mechanical strength of the electrically conductive fibrous web layer decreases, handling becomes difficult, and manufacturing may not be easy. In addition, if the basis weight exceeds 100 g/m 2 , it may be difficult to implement an electrically conductive fibrous web layer in which an electrically conductive layer is uniformly formed outside the fiber, and compression characteristics may deteriorate.

In addition, the electrically conductive fibrous web layer 110 may be formed by stacking a plurality of electrically conductive fibrous webs to satisfy an appropriate thickness. However, when the electrically conductive fibrous web layer is composed of one electrically conductive fibrous web or several electrically conductive fibrous webs are laminated, the electrically conductive fibrous web layer 110 has a hole diameter in the thickness direction from the first surface to the second surface. It is preferable to implement such that there is no gradient, that is, the pore size is uniform in the thickness direction. If the electrically conductive fibrous web layer is implemented to have a pore size gradient in the thickness direction, during a pressurizing process for forming the electrically conductive adhesive portion 120 or insulating adhesive portion 130, for example, a roll press, which will be described later, There is a very high possibility of causing a difference in the density of the laminated fiber web depending on the position, and this may cause deterioration in appearance quality such as wrinkles in the fabric. In addition, the filling amount of the material forming the electrically conductive adhesive portion 120 or the insulating adhesive portion 130 may vary depending on the difference in density in the thickness direction (or the difference in pore size or porosity), so that the electrically conductive adhesive portion 120 ) or the thickness of the insulating adhesive portion 130 may be non-uniform, and such non-uniformity may become more severe during extrusion after mounting on the shield can, causing changes over time such as a decrease in adhesive strength.

In addition, the electrically conductive fibrous web layer 110 may have a porosity of 30 to 80%. If the porosity is less than 30%, compression characteristics may deteriorate, and if the porosity exceeds 80%, mechanical strength of the electrically conductive fibrous web layer may decrease.

Next, the electrically conductive adhesive portion 120 provided on the first surface of the above-described electrically conductive fibrous web layer 110 will be described. The electrically conductive adhesive portion 120 serves to fix the electromagnetic wave shielding sheets 100 and 200 on the shield can 500, and may be formed of an electrically conductive adhesive to improve electromagnetic wave shielding and heat transfer characteristics. The electrically conductive adhesive includes an adhesive component 121 and an electrically conductive filler 122, and known adhesive components can be used as the adhesive component 121 without limitation. Or it may be a mixture of two or more. In addition, the electrically conductive filler 122 may be at least one selected from the group consisting of nickel, nickel-graphite, carbon black, graphite, aluminum, copper, and silver. In addition, the electrically conductive adhesive may include the electrically conductive filler 122 in an amount of 5 to 95% by weight based on the total weight of the electrically conductive adhesive.

On the other hand, the electrically conductive adhesive portion 120 formed of the above-described electrically conductive adhesive includes the electrically conductive adhesive layer 120a formed to have a predetermined thickness on the first surface of the electrically conductive fibrous web layer 110 described above, and the electrically conductive adhesive layer 120a. It is made of an electrically conductive adhesive 120b which is connected to the conductive adhesive layer 120a and fills the internal pores of the electrically conductive fibrous web layer 110. Since the electrically conductive adhesive 120b fills all or part of the internal pores of the electrically conductive fibrous web layer 110, the vertical resistance of the electrically conductive fibrous web layer 110 can be reduced, thereby exhibiting more improved electromagnetic wave shielding performance. can be advantageous for

In addition, the electrically conductive adhesive layer 120a may have a thickness of 5 to 50 μm, for example, 5 to 30 μm, or 10 to 20 μm. It may be advantageous to have sufficient electromagnetic wave shielding performance and adhesion characteristics with the surface of the shield can.

Next, the insulating adhesive portion 130 including the insulating adhesive layer formed to a predetermined thickness on the second surface of the electrically conductive fibrous web layer 110 described above will be described.

The insulating bonding portion 130 is positioned between the insulating heat dissipating portion 140 and the electrically conductive fibrous web layer 110 to prevent degradation of electromagnetic wave shielding performance due to dielectric breakdown of the insulating heat dissipating portion 140 described later. That is, the electromagnetic wave shielding performance can exhibit excellent characteristics when the vertical resistance of the electrically conductive fibrous web layer 110 corresponding to the electromagnetic wave shielding unit is low and the vertical resistance of the entire electromagnetic wave shielding sheet 100 or 200 is high. When the insulating properties of the insulating heat dissipation unit 140 are destroyed after being installed in a device, the electromagnetic wave shielding performance may deteriorate over time. In particular, as the resin or the insulating heat-dissipating filler constituting the insulating heat-dissipating portion 140 is more vulnerable to moisture, insulation breakdown is easily achieved, resulting in large fluctuations in electromagnetic wave shielding performance. In addition, when the resin constituting the insulating heat dissipating portion 140 is attacked by moisture or the like, the interface characteristics between the electrically conductive fibrous web layer 110 and the insulating heat dissipating portion 140 may be deteriorated, and thus the heat transfer characteristics may also be deteriorated. Therefore, in the present invention, even if the insulating heat dissipation unit 140 is insulated by moisture or the like and interface characteristics deteriorate, the vertical resistance of the entire electromagnetic wave shielding sheet 100, 200 can be maintained similar to the initial design value. , It includes an insulating adhesive portion 130 to prevent the insulating heat dissipation portion 140 from being lifted or peeled off from the electrically conductive fibrous web layer 110 to prevent change in heat transfer characteristics over time.

For the insulating adhesive portion 130, any known adhesive material capable of exhibiting insulating properties while having adhesive properties may be used without limitation, and for example, an acrylic adhesive resin or a silicone adhesive resin may be used.

In addition, the insulating adhesive portion 130 may form an insulating adhesive layer with a predetermined thickness on the second surface of the electrically conductive fibrous web layer 110 as shown in FIG. 1, or as shown in FIG. The adhesive portion 130' may further include an insulating adhesive 130a disposed in pores inside the electrically conductive fibrous web layer 110 following the insulating adhesive layer 130b. When the insulating adhesive 130a is disposed in the internal pores of the electrically conductive fibrous web layer 110, the adhesive properties between the insulating adhesive portion 130' and the electrically conductive fibrous web layer 110 may be further improved. In addition, it is more advantageous to prevent the thickness change of the insulating adhesive layer 130b or the thickness change of the electrically conductive adhesive layer 120a that may occur due to the load applied when the shield can 500 and the metal bracket 600 are assembled. can Specifically, the internal pores of the electrically conductive fibrous web layer 110 are advantageous for the electromagnetic wave shielding sheet to have flexibility, stretchability and compression characteristics, but on the first and second surfaces of the electrically conductive fibrous web layer 110 The electrically conductive adhesive layer or insulating adhesive layer layered to a predetermined thickness is compressed and gradually pushed into the internal pores of the electrically conductive fibrous web layer 110 during use, causing thickness fluctuations in the electrically conductive adhesive layer and / or insulating adhesive layer. there is However, if the internal pores of the electrically conductive fibrous web layer 110 are filled with the electrically conductive adhesive 120b or the insulating adhesive 130a in advance, even if a load is applied to the electromagnetic wave shielding sheet, the electrically conductive adhesive layer 120a or the insulating adhesive layer 130b ) can be prevented from being pushed into the internal pores of the electrically conductive fibrous web layer 110, and through this, it can be advantageous to prevent the change in adhesive strength and adhesive strength over time.

Accordingly, preferably, 90%, 95%, or 98% of the total pore volume of the internal pores of the electrically conductive fibrous web layer 110 may be filled with the electrically conductive adhesive 120b, or all of the pores may be filled. Alternatively, even when the internal pores of the electrically conductive fibrous web layer 110 are filled with the insulating adhesive 130a and the electrically conductive adhesive 120b, they may be implemented so as to fill all internal pores of the electrically conductive fibrous web layer 110. Through this, it is possible to prevent the aging change of adhesive strength and adhesive strength. On the other hand, when the internal pores of the electrically conductive fibrous web layer 110 are filled with the insulating adhesive 130a and the electrically conductive adhesive 120b, preferably 90% or more of the total volume of the internal pores of the electrically conductive fibrous web layer 110, in another embodiment 95% or more, for example, 98% or less may be filled with the electrically conductive adhesive 120b, and through this, sufficient electromagnetic wave shielding performance may be expressed.

Meanwhile, the insulating adhesive layer 130b layered on the second surface of the electrically conductive fibrous web layer 110 may have a thickness of 7 to 20 μm, or, for example, 10 to 15 μm. If the thickness is less than 7 μm, it may not be easy to form a layer due to the thin thickness, and a part of the insulating adhesive layer 130b is pushed into the pores of the conductive fibrous web layer 110 by the pressure applied to the electromagnetic wave shielding sheet during use. If it enters, the layer thickness becomes thinner than the initially designed one, so the adhesive force may fluctuate, and there is a concern that the insulation characteristics may also vary depending on the location. In addition, when the thickness exceeds 20 μm, heat transfer efficiency from the electrically conductive fibrous web layer 110 to the insulating heat dissipating portion 140 may be reduced.

In addition, the insulating adhesive 130a located inside the conductive fibrous web layer 110 preferably has an electrical conductivity having a thickness (d) within 10% of the total thickness of the electrically conductive fibrous web layer 110, for example, within 5%. It may be located near the second surface of the fiber web layer 110, and through this, it may be advantageous to achieve insulating properties, adhesive and adhesive properties, and electromagnetic wave shielding properties.

Next, the insulating heat dissipation part 140 disposed on the above-described insulating bonding parts 130 and 130' will be described. The insulating heat dissipation part 140 is the conductive fiber web layer 110 and the metal bracket 600 when the heat emitted from the element is transferred to the metal bracket 600 via the shield can 500 and the conductive fiber web layer 110. As a supplement to the heat transfer interface between the surfaces, it may be typically formed of a thermal interface material (TIM). However, as described above, when considering the electromagnetic wave shielding performance, the electromagnetic wave shielding sheets 100, 101, and 200 should have insulating characteristics in the entire thickness direction, so they are implemented to have insulating characteristics in addition to heat dissipation characteristics. To this end, it is preferable that the insulating heat dissipation part 140 uses a known heat dissipation interface material (TIM) having strong insulation, for example, one having an insulating heat dissipation filler as a heat dissipation filler. The insulating heat dissipating filler may employ a known filler, and may include, for example, at least one ceramic filler selected from the group consisting of alumina, yttria, zirconia, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and single crystal silicon. .

In addition, the thickness of the insulating heat dissipation portion 140 may be 30 to 200 μm, but is not limited thereto, and may be adjusted in consideration of heat dissipation characteristics and a desired overall thickness of the electromagnetic wave shielding sheet.

Meanwhile, a release film 150 may be further included on the electrically conductive adhesive portion 120 to protect a surface until mounted on an electronic component or the like, and the release film 150 may be a known PET film or the like. On the other hand, although not shown, a release film for protecting the surface of the insulating heat dissipation unit 140 may be further included until mounted on an electronic component or the like.

The aforementioned electromagnetic wave shielding sheets 100, 101, and 200 may have a thickness of 250 μm or less, for example, 170 μm or less, or 120 μm or less. In addition, the electromagnetic wave shielding sheets 100, 101, and 200 may have an insulation resistance of 1.0 GΩ/□ or more in a thickness direction, and a horizontal resistance measured for an electrically conductive adhesive portion of 0.05 Ω/□ or less. Here, the insulation resistance in the thickness direction is a resistance value measured between both main surfaces of the electromagnetic wave shielding sheet, and specifically, energizing SUS is attached to the electrically conductive adhesive portion of the electromagnetic wave shielding sheet specimen having a size of 25 × 25 mm, and insulating heat dissipation This is the insulation resistance value measured between the SUS and the meta form by applying a voltage of 500 V between the SUS and the metal form after placing a 15 × 15 mm conducting metal form on the part. In addition, the horizontal thermal conductivity of the electromagnetic wave shielding sheets 100, 101, and 200 in a horizontal direction, that is, in a direction parallel to the main surface, may be 3 W/m·K or more. At this time, the horizontal thermal conductivity is measured by a laser/light flash analysis (LFA) flash method.

In addition, when the electromagnetic wave shielding sheets 100, 101, and 200 are compressed perpendicularly to the surface direction of the main surface with a load of 1 kg f/mm 2 , the thickness reduction rate (%) based on the thickness before compression may be 20% or more.

The above-described electromagnetic wave shielding sheets 100, 101, and 200 may be manufactured through a manufacturing method described later, but are not limited thereto.

The electromagnetic wave shielding sheet (100, 101, 200) is prepared by: (1) manufacturing an electromagnetic wave shielding portion, which is an electrically conductive fibrous web layer having opposing first and second surfaces, (2) electrically conductive fibrous web layer on the first side Forming an electrically conductive adhesive portion by applying heat and/or pressure after processing the adhesive, and (3) processing an insulating adhesive on the second surface of the electrically conductive fibrous web to form an insulating adhesive portion including an insulating adhesive layer, and (4) It may be manufactured through the step of forming an insulating heat dissipation part on the insulating bonding part.

First, as step (1), a step of manufacturing an electromagnetic wave shielding portion that is an electrically conductive fibrous web layer having opposing first and second surfaces will be described.

The electrically conductive fibrous web layer may be prepared by forming a fibrous web layer and coating an electrically conductive layer on fibers in the fibrous web layer. Alternatively, it may be prepared through the step of preparing an electrically conductive composite fiber coated with an electrically conductive layer on the fiber and the step of manufacturing the electrically conductive composite fiber into an electrically conductive fibrous web layer.

Referring to the former method among the methods for manufacturing the electrically conductive fibrous web layer, the fibrous web layer may be manufactured through a calendering process for a fibrous mat formed by accumulating nanofibers spun through electrospinning. Alternatively, conventional fibers may be manufactured by processing fibers by a known method such as chemical bonding nonwoven fabric, thermal bonding nonwoven fabric, dry nonwoven fabric such as air-lay nonwoven fabric, wet-laid nonwoven fabric, spanless nonwoven fabric, needle punched nonwoven fabric, or meltblown. The fiber may be chemically spun or electrospun depending on its diameter, and since the chemical spinning and electrospinning can be performed under known conditions and methods, a detailed description thereof is omitted in the present invention. However, the fiber web layer is prepared by electrospinning with a spinning solution in which PVDF and polyurethane are mixed as fiber forming components in order to achieve the smaller diameter of the fiber to improve the electromagnetic wave shielding performance, and to achieve compressive properties and mechanical strength at the same time. it could be

Next, a step of forming an electrically conductive layer on the fibers of the prepared fiber web layer may be performed. In this step, a known method of forming an electrically conductive layer to cover the fibers may be employed, and examples thereof include deposition of an electrically conductive layer, plating, and a coating method using an electrically conductive paste. However, in the deposition of the electrically conductive layer, the electrically conductive layer can be deposited only on the outside of the fibers located on the surface of the fiber web layer, and it can be difficult to provide the electrically conductive layer on the fibers located in the center of the fiber web layer, so that the desired level is achieved. Therefore, it may be difficult to express the electromagnetic shielding effect. In addition, as the pores of the surface portion of the fiber web layer on which the electrically conductive layer is deposited may be closed, the compression characteristics of the fiber web layer may deteriorate, and the deposited portion may be easily crushed or peeled off during compression. In addition, when the fibrous web layer is coated with the electrically conductive paste, the fibers located in the surface and central portions of the fibrous web layer can be evenly coated, but the compression characteristics are lowered due to pore closure and the electrically conductive layer is broken during compression due to this, Delamination can be severe. Accordingly, preferably, the electrically conductive layer may be formed on the fiber web layer through plating, and more preferably, the plating may be electroless plating.

Next, as step (2) according to the present invention, a step of forming an electrically conductive adhesive portion by applying heat and/or pressure after treating the electrically conductive adhesive on the first surface of the prepared electrically conductive fibrous web layer is performed.

The electrically conductive adhesive may be directly applied on the first surface in a non-dried composition state, or separately, after forming a dried electrically conductive adhesive layer to have a predetermined thickness on a release film, the electrically conductive adhesive layer It may be laminated on the first surface to form an electrically conductive adhesive portion.

As the electrically conductive adhesive, those known in the art may be used without limitation. The electrically conductive adhesive may include an adhesive resin and an electrically conductive filler, may include a solvent or dispersant in an undried state, and additives such as other known leveling agents, plasticizers, sunscreens, antioxidants, and antistatic agents may further include. The adhesive resin may be, for example, a silicone-based adhesive resin or an acrylic adhesive resin. The electrically conductive filler may include at least one selected from the group consisting of nickel, nickel-graphite, carbon black, graphite, aluminum, copper, and silver.

On the other hand, the electrically conductive adhesive may be treated in an amount sufficient to form an electrically conductive adhesive layer with a predetermined thickness on the first surface of the electrically conductive fibrous web layer and at the same time fill the pores of the electrically conductive fibrous web layer. In addition, pressure may be applied after processing the electrically conductive adhesive so that the treated portion fills the pores of the electrically conductive fibrous web layer, and if partial or complete curing is required, heat may be applied together with pressure. The applied pressure may be appropriately selected in consideration of the thickness of the electrically conductive fibrous web layer, the porosity, the pore size, and the viscosity of the electrically conductive adhesive, and the applied heat may also be appropriately selected in consideration of the composition of the electrically conductive adhesive. not particularly limited to

Next, as step (3) according to the present invention, a step of forming an insulating adhesive portion including an insulating adhesive layer by treating an insulating adhesive on the second surface of the electrically conductive fibrous web layer is performed. The insulating adhesive may include a known adhesive resin, may further include a solvent in an undried state, and may further include other additives.

It is preferable that the insulating adhesive does not contain other components such as fillers that can reduce the insulating properties of the adhesive resin in order to secure the insulating properties of the electromagnetic wave shielding sheet even in case of insulation breakdown of the insulating heat dissipating part.

The insulating adhesive may be directly treated on the second surface of the electrically conductive fibrous web layer to form an insulating adhesive layer having a predetermined thickness. Alternatively, an insulating adhesive layer may be separately formed on the release film to a predetermined thickness and then laminated to the second surface.

After the insulating adhesive is applied on the second side of the electrically conductive fibrous web layer, pressure may be further applied, thereby flattening the surface of the insulating adhesive layer and filling the electrically conductive adhesive from the second side to the first side of the electrically conductive fibrous web layer. The insulative adhesive can fill the pores that are not present, and through this, it is possible to prevent the change in the adhesive force of the electrically conductive adhesive due to the change over time even when it is mounted on an electronic device in a compressed state.

In addition, heat may be applied together when pressure is applied for curing part or all of the insulating adhesive, which varies depending on the composition of the insulating adhesive, and the present invention is not particularly limited thereto.

Next, as step (4) according to the present invention, a step of forming an insulating heat dissipation part on the insulating adhesive part is performed. The insulating heat-dissipating part may be preferably implemented by heat-laminating an insulating adhesive part and an insulating heat-dissipating material formed to a predetermined thickness by processing an insulating heat-dissipating material on a separate release film. The insulating heat-dissipating material may be a known heat-dissipating interface material, and may include a ceramic-based heat-dissipating filler as a heat-dissipating filler for insulating properties.

The electromagnetic wave shielding sheets 100 , 101 , and 200 implemented through the above-described manufacturing method may be provided in electronic components such as electromagnetic wave shielding type circuit modules or electronic devices. As an example, referring to FIGS. 4 and 5, the element 400, which is a source of electromagnetic waves or requires protection from electromagnetic waves irradiated from the outside, is placed on the upper side of the shield can 500 provided on the circuit board 300 mounted thereon. For example, the conductive adhesive part of the electromagnetic wave shielding sheet 200 is disposed on the top of the shield can 500 so that it directly contacts, and the metal bracket 600 is disposed on the upper side of the electromagnetic wave shielding sheet 200. For example, the electromagnetic wave shielding The metal bracket 600 may be disposed so that the insulating heat dissipation part of the sheet 200 directly contacts. At this time, the electromagnetic wave shielding sheet 200 may have a body 210 and an opening 220 perforated in a predetermined area so that the opening 220 corresponds to the open top and bottom of the shield-can 500. can be placed. This is to transfer the heat (H) generated from the element 400 to the metal bracket 600 side without being trapped by the electromagnetic shielding sheet 200 or the shield can 500, and to make this easier, the element 400 ) It may further include a heat dissipation material layer (not shown) connecting the metal bracket 600 from the upper part.

The element 400 may be a known element mounted on a circuit board in an electronic device such as a driving chip, and may be an element that generates electromagnetic waves and/or heat or is sensitive to electromagnetic waves and easily malfunctions.

In addition, the circuit board 300 may be a known circuit board provided in an electronic device, and may be, for example, a PCB or FPCB. Since the size and thickness of the circuit board 300 can be changed according to the internal design of the electronic device to be implemented, the present invention is not particularly limited thereto.

In addition, the shield can 500 is disposed on the circuit board 300 described above, includes a side wall to surround at least one region on the circuit board 300 including the element 400, and an upper portion may be bent. It may have a structure in which the upper and lower sides are open. The shield can 500 may be a material of a shield can typically provided on a circuit board to shield electromagnetic waves, and may be, for example, nickel silver. Since the width and height of the shield can 500 may be appropriately changed in consideration of the size, thickness, etc. of a circuit board and an electronic device equipped with the shield can, the present invention is not particularly limited thereto.

In addition, the metal bracket 600 is disposed above the shield can 500 to protect the circuit board 300 on which the device 400 is mounted. Since the material of the metal bracket 600 may be a known material, the present invention is not particularly limited thereto, and may be, for example, a metal such as aluminum. Since the shape and size of the metal bracket 600 can be changed according to the size of the printed circuit board and the internal design of the electronic device, the present invention is not particularly limited thereto.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention may add elements within the scope of the same spirit. However, other embodiments can be easily proposed by means of changes, deletions, additions, etc., but these will also fall within the scope of the present invention.

100, 101, 200: electromagnetic wave shielding sheet
110: electrically conductive fiber web layer 120: electrically conductive adhesive portion
130: insulating adhesive part 140: insulating heat radiating part
300: circuit board 400: element
500: shield can 600: metal bracket

Claims (17)

an electromagnetic wave shielding portion that is an electrically conductive fibrous web layer having opposing first and second surfaces;
Consisting of an electrically conductive adhesive layer formed on the first surface of the conductive fibrous web layer to a predetermined thickness and an electrically conductive adhesive disposed in all or part of the pores of the electrically conductive fibrous web layer following the electrically conductive adhesive layer electrically conductive adhesive;
an insulating adhesive portion including an insulating adhesive layer formed to a predetermined thickness on the second surface of the electrically conductive fibrous web layer; and
An electromagnetic wave shielding sheet for a shield can comprising an insulating heat dissipation part formed on the insulating adhesive part. According to claim 1,
The electromagnetic wave shielding sheet for a shield-can has at least one opening having a predetermined area in a region corresponding to an element disposed inside the shield-can. According to claim 1,
The thickness of the electrically conductive fibrous web layer is 5 to 50 μm, and the basis weight is 5 to 100 g / m 2 Electromagnetic wave shielding sheet for a shield can. According to claim 1,
The electrically conductive fibrous web layer is an electromagnetic wave shielding sheet for a shield can comprising electrically conductive composite fibers coated with an electrically conductive layer on an outer surface of the fiber. According to claim 4,
The electrically conductive composite fiber has a diameter of 0.2 ~ 10㎛, and the thickness of the electrically conductive layer is 0.1 ~ 2㎛ electromagnetic wave shielding sheet for a shield can. According to claim 4,
The electrically conductive layer is formed of at least one metal selected from the group consisting of aluminum, nickel, copper, silver, gold, chromium, platinum, titanium alloy, and stainless steel, and at least one conductive polymer compound. Electromagnetic wave shielding sheet for a shield can. According to claim 1,
The electromagnetic wave shielding sheet for a shield can, characterized in that the electrically conductive fibrous web layer has no pore size gradient in the thickness direction from the first surface to the second surface. According to claim 1,
The electrically conductive adhesive is an electromagnetic wave shielding sheet for a shield can disposed to fill all pores inside the electrically conductive fibrous web layer. According to claim 1,
The insulating adhesive portion further comprises an insulating adhesive disposed in the pores of the conductive fibrous web layer following the insulating adhesive layer,
The insulating adhesive and the electrically conductive adhesive are disposed so as to completely fill the pores in the electrically conductive fibrous web layer. According to claim 1,
The thickness of the electrically conductive adhesive layer is 5 to 50 μm, the thickness of the insulating adhesive layer is 7 to 15 μm, and the thickness of the insulating heat radiation portion is 30 to 200 μm. According to claim 1,
The electromagnetic wave shielding sheet for a shield can having at least one ceramic filler selected from the group consisting of alumina, yttria, zirconia, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and single crystal silicon. According to claim 1,
An electromagnetic wave shielding sheet for a shield-can having an opening in a predetermined area of the electromagnetic wave shielding sheet so as not to block the movement of heat generated from a device and radiated upward of the shield-can. According to claim 1,
An electromagnetic wave shielding sheet for shield cans with an insulation resistance in the thickness direction of 1.0GΩ/□ or more and a horizontal resistance of the electrically conductive adhesive part of 0.05 Ω/□ or less. According to claim 1,
Electromagnetic shielding sheet for shield cans with horizontal thermal conductivity of 3W/m K or higher. According to claim 1,
Electromagnetic shielding sheet for shield cans with a thickness reduction rate of more than 20% based on the thickness before compression when compressed with a load of 1kg f/mm2 perpendicular to the plane direction. a circuit board on which devices are mounted;
a shield can having sidewalls surrounding at least an area of the circuit board on which the device is mounted, and having upper and lower portions open;
The shield according to any one of claims 1 to 15, including a predetermined opening in a region corresponding to at least the element, and disposed on an upper side of the shield-can so that the opening corresponds to an open top of the shield-can. electromagnetic wave shielding sheets for cans; and
An electromagnetic shielding circuit module comprising: a metal bracket disposed on an upper side of the shield-can so that one side thereof comes into contact with the electromagnetic wave shielding sheet for the shield-can. An electronic device comprising the electromagnetic shielding type circuit module according to claim 16.

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