JP2004111566A - Multilayer printed board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed board by which the reducing effect of noise influence is improved without mounting a noise-countermeasure component. <P>SOLUTION: By laminating a plurality of resin films 23 and 21 including a conductor pattern film 21 consisting of a thermoplastic resin and pressurizing them while heating, the films 23 and 21 are pasted to each other and multilayered. The multilayer printed board obtained like this is provided with an element layer 41 functioning as a noise absorber on the side of the inner layer of the plurally laminated resin film, a ground layer 22g formed in the laminating direction of the element layer 41 and consisting of a conductor pattern 22, a noise conductor part 46 connected electrically with the element layer 41 for guiding noise, and a shielding part 70 consisting of the plurally laminated resin films forming a board area in the neighborhood of the noise conductor part 46. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer printed circuit board.
[0002]
[Prior art]
As a countermeasure against noise in electronic devices, there is generally a shield structure such as a metal case for accommodating a printed circuit board or a shield cover covering a part of the printed circuit board (Japanese Patent Application Laid-Open Nos. 9-18181 and 2001-144388). In each of these types of shield structures, a separate member dedicated to noise suppression is mounted on a printed circuit board or an element. It mainly absorbs or shields electric noise that enters the inside of the electronic device from the connector opening and electric noise that radiates from the inside of the electronic device to the outside.
[0003]
[Problems to be solved by the invention]
In the above prior art, in addition to electronic components such as elements for realizing the original function of the product, the noise suppression dedicated component had to be separately incorporated in the product, that is, on the printed circuit board, so from the viewpoint of high density mounting and the like. Disadvantage in mounting area, cost, and the like.
[0004]
In addition, since noise suppression elements must be relatively discretely arranged due to restrictions on arrangement, the effect is insufficient due to the influence of wiring impedance.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a multilayer printed circuit board that can improve the effect of reducing the influence of noise without separately mounting noise suppression components. .
[0006]
[Means for Solving the Problems]
According to claim 1 of the present invention, a conductor pattern film in which a conductor pattern is formed on at least one surface of a film made of a thermoplastic resin, and a plurality of resin films including the conductor pattern film are laminated and heated and pressed. By bonding the resin films to each other and forming a multilayer printed circuit board, an element layer functioning as a noise absorber on the inner layer side of a plurality of laminated resin films, and a stacking direction of the element layers. A ground layer formed of a conductor pattern, a noise conductor portion electrically connected to the element layer and guiding noise, and a shield formed of a plurality of laminated resin films forming a substrate region near the noise conductor portion It has a shielding part.
[0007]
This makes it possible to dispose a noise absorber such as a dielectric or a varistor material on the inner layer side as an element layer in a multilayer printed circuit board in which laminated resin films are bonded to each other to form a multilayer. As a result, instead of separately mounting noise suppression components, they are formed simultaneously with the formation of the printed circuit board, and the noise reduction effect can be improved by the built-in element layer. For example, when external noise enters from a connector or the like, the dielectric constant (ε) or the power factor (tan δ) of the insulator is relatively large as the noise absorber as compared with the resin film forming the insulating base material of the multilayer printed circuit board. It is possible to absorb the noise and reduce the influence of the noise by using a dielectric material or the like made of a large material.
[0008]
Further, when forming a multilayer, it is possible to arrange a relatively wide ground layer. Due to the relatively wide ground layer, for example, by bending a flexible resin film, forming a shield shielding portion for shielding noise intrusion and radiation without mounting a separate member. Is possible.
[0009]
According to the second aspect of the present invention, the shield shielding portion is provided with a slit for bending or rolling a plurality of laminated resin films.
[0010]
Thus, the shield shielding portion can be easily formed without mounting a separate member.
[0011]
According to the third and fourth aspects of the present invention, it is possible to provide a conductive terminal capable of making contact with a metal case as a housing for housing the printed circuit board in the shield shielding portion. As a result, it is possible to stably connect to the metal case via the conduction terminal.
[0012]
According to claim 5 of the present invention, the noise conductor portion includes a conductor pattern laminated outside the element layer and the ground layer, and a through hole electrically connected to the conductor pattern and the element layer.
[0013]
According to this, as a nozzle conductor for guiding noise to an element layer as a noise absorber, a through hole penetrating a multilayer printed board is used to electrically connect a conductor pattern formed on both outer sides of the multilayer printed board and an element layer. Connection is possible. As a result, the shortest path, that is, low impedance, can be achieved as a path for guiding noise to the element layer.
[0014]
According to claim 6 of the present invention, the surface of the multilayer printed circuit board according to any one of claims 1 to 5 is a mounting surface of an electronic component, and the element layer should connect the element layer. It is provided below and near the electronic component.
[0015]
The element layer functioning as a noise absorber can be provided below and near an electronic component to be connected to the element layer, for example, a connector portion. As a result, the element layer can be arranged almost immediately near the wiring terminal of the connector portion, which is the ideal arrangement position, so that the noise reduction effect can be further improved.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a multilayer printed board according to the present invention will be described with reference to the drawings.
[0017]
(1st Embodiment)
FIG. 1 is a perspective view illustrating a schematic configuration of a multilayer printed circuit board according to the present embodiment. FIG. 2 is a plan view showing the multilayer printed circuit board before bending the shield shield in FIG. FIG. 3 is a cross-sectional view showing a configuration around an element layer as a noise absorber in FIG. FIGS. 4A to 4G are cross-sectional views illustrating a method of manufacturing a multilayer printed circuit board according to the present embodiment in a schematic manufacturing process. FIGS. It is sectional drawing which shows a state.
[0018]
As shown in FIGS. 1, 2 and 3, the multilayer printed board 1 of the present invention has a conductor pattern film 21 in which a conductor pattern 22 is formed on at least one surface of a film 23 made of a thermoplastic resin (see FIG. 4). , And a plurality of resin films 23 including the conductor pattern film 21 are laminated and pressed while heating, whereby the resin films 23 are bonded to each other to form a multilayer. After the multilayer printed board 1 is divided into a plurality of board portions in the laminating direction and molded by heating and pressurizing in advance, the board portions are bundled and heated and pressed collectively by a hot press plate or the like. Thus, it is possible to form the multilayer printed circuit board 1 having a multilayer structure. Further, as will be described in a method of manufacturing the multilayer printed board 1 described later, for example, an electric element 41 (see FIG. 4) for noise suppression is formed on the inner layer side of the laminated resin films 23 in a multilayered manner. Sometimes it is possible to mold simultaneously with the substrate area. The method for manufacturing the multilayer printed circuit board 1 will be described later.
[0019]
In the case where the electric element 41 is formed simultaneously with the multi-layer molding, an interlayer composition 51 for electrically connecting the electric element 41 and the conductor pattern 22 formed in the laminating direction of the electric element 41 is formed inside. In the through holes or vias (hereinafter, referred to as via holes) 24, it is possible to obtain a ripple effect in which the positioning of the electric element 41 with respect to the resin film 23 as the insulating base material can be easily performed. Further, when the substrate portion is divided in the laminating direction and molded, and when the substrate is molded in a lump, the electronic element 41 which is an inner layer on the inner layer side is simultaneously molded in a multi-layer molding step as a result. Is possible.
[0020]
In the present embodiment, an explanation will be given below assuming that the electric element 41 is formed integrally with the multilayer printed circuit board 1. In the multilayer printed board 1, a plurality of resin films 23 and 21 including the single-sided conductor pattern film 21 (four in FIG. 3 of the present embodiment) are laminated. Furthermore, in the multilayer printed board 1, between the conductor patterns 22 to be laminated, or between the conductor pattern 22 and the electric element 41, an electric circuit is formed. The components may be electrically connected to each other by the integrated conductive composition 51 therein.
[0021]
Further, in the present embodiment, as shown in FIGS. 1 and 3, an electric element (hereinafter, referred to as an element layer) 41 disposed on the inner layer side of the multilayer printed board 1 and functioning as a noise absorber, and the element layer 41, a ground layer 22g composed of the conductor pattern 22 and a noise conductor portion 46 electrically connected to the element layer 41 and guiding noise. Thereby, in the multilayer printed circuit board 1 in which the laminated resin films 23 and 21 are bonded to each other to form a multilayer, the material layer constituting the noise absorber such as a dielectric or a varistor material is used as the element layer 41 as the inner layer. It is possible to arrange on the side. As a result, instead of separately mounting noise suppression components as in the prior art, the noise reduction effect can be improved by the electric element 41 which is formed at the same time as the multi-layer printed circuit board 1 is formed and is incorporated.
[0022]
As a dielectric, the dielectric constant (ε) is relatively compared to the dielectric constant of the resin films 23 and 21 (specifically, the film 23 made of a thermoplastic resin) constituting the insulating base material of the multilayer printed circuit board 1. Larger is desirable. Thus, the element layer 41 made of a material having a relatively large dielectric constant or the like can absorb noise and reduce the influence of the noise. In addition, the capacitor (see FIG. 6E of the third embodiment) formed of the element layer 41 and the conductor pattern 22 formed in the direction in which the element layer 41 is laminated has electric power guided through the noise conductor portion 46. High-frequency noise components may be removed from the signal.
[0023]
In addition, the element layer 41 used as a noise absorber may be disposed in the same layer in the substrate region, or may be disposed partially. Note that, in the present embodiment, as shown in FIG. In this case, as a material for forming the element layer 41, in addition to having a high dielectric constant, there is a problem in an electric circuit formed by the conductor pattern 22 or the interlayer composition 51 formed on the multilayer printed circuit board 1. As long as there is no influence, a material having an insulator power factor (tan δ) that is relatively larger than the resin films 23 and 21 (specifically, the film 23 made of a thermoplastic resin) may be used. Thus, the noise component, which is electrical energy, is converted into thermal energy or the like by utilizing the magnitude of the insulator power factor, thereby removing or reducing noise.
[0024]
Further, in the multilayer printed board 1 of the present embodiment, a relatively wide ground layer 22g can be arranged as a ground layer made of the above-described conductor pattern 22 when performing multilayer molding.
[0025]
Further, in the present embodiment, the multilayer printed board 1 includes a shield shielding section 70 formed by using the resin films 23 and 21 that form a board area near the noise conductor section 46. Further, since the multilayer printed board 1 uses the film 23 made of a thermoplastic resin as an insulating base material, the board itself can have flexibility, and the multilayer printed board 1 having flexibility can be provided. It is possible to do.
[0026]
Thereby, by bending the resin films 23 and 21 having flexibility, a shield cover of a member different from the conventional multilayer printed circuit board 1 can be mounted due to the relatively wide ground layer 22g. In addition, it is possible to form the shield shielding part 70 that shields noise intrusion and radiation.
[0027]
Furthermore, in the present embodiment, in the multilayer printed circuit board 1, the area where the shield shielding section 70 is to be formed in the substrate area near the noise conductor section 46 which is a path for guiding noise to the element layer 41 is shown in FIG. As described above, the resin films 23 and 21 are provided with the slits 70a for bending or rounding. This makes it easy to form the shield shield portion 70 by utilizing the flexibility of the multilayer printed board 1 without mounting a shield component such as a shield cover, which is a member separate from the multilayer printed board 1.
[0028]
Here, as shown in FIG. 3, the noise conductor portion 46 in which the shield portion 70 is disposed in the vicinity includes the element layer 41 functioning as a noise absorber and the conductor pattern 22 laminated outside the ground layer 22 g. It is desirable to provide a through hole 47 for electrically connecting the conductor pattern 22 and the element layer 41. A noise conductor part 46 for guiding noise to the element layer 41 as a noise absorber is connected to the conductor pattern 22 and the element layer 41 formed on both outer sides of the multilayer printed board 1 by through holes 47 penetrating the multilayer printed board 1. The connection can be made with the shortest conductive path. As a result, as a path for guiding noise to the element layer 41, the impedance of the path can be reduced.
[0029]
Further, in the present embodiment, as shown in FIGS. 1 and 3, as an electronic component that transmits unnecessary electric noise or radiated noise to the noise conductor portion 46, an electric signal or the like is transmitted from an external electronic device or the like to the multilayer printed circuit board 1. A connector section 80 for inputting / outputting a high-frequency signal is provided. Thus, the element layer 41 functioning as a noise absorber can be provided below and near the connector section 80 (specifically, the wiring terminal 80a of the connector section) which is an electronic component to be connected to the element layer. . As a result, since the element layer 41 can be arranged almost immediately near the wiring terminal 80a of the connector section 80 that is ideally arranged, the noise reduction effect can be further improved.
[0030]
In addition, as shown in FIGS. 1 and 2, it is desirable that a conduction terminal 70 b connected to the ground layer 22 g extends from the shield shielding portion 70. Thus, the shield shielding portion 70 in which the ground layer 22g is disposed relatively widely can be stably connected to the ground via the conduction terminal 70b, for example, to a metal case as a housing for housing the multilayer printed circuit board 1. Is possible.
[0031]
Therefore, as shown in FIGS. 1 and 3, the connector section 80 where unnecessary noise may be emitted or penetrated is covered with the shield shield section 70, so that the multilayer printed circuit board 1, that is, the electronic device radiates from the inside to the outside. It is possible to absorb or shield the generated electrical noise by the shield shielding unit 70, and the noise reduction effect can be efficiently improved.
[0032]
Next, a method for manufacturing the multilayer printed board 1 of the present invention, particularly a method for manufacturing the multilayer printed board 1 having the element layer 41 on the inner layer side of the plurality of laminated resin films 23 and 21 will be described with reference to FIG. Note that, in FIG. 4, a description will be given of a five-layered multilayer printed circuit board for convenience, in contrast to the four-layer printed circuit board 1 shown in FIG. Note that, as shown in FIG. 4, the thickness of the element layer 41 is substantially twice the thickness of the resin film 23, and the number of layers to be laminated according to the thickness of the element layer 41 and the resin film 23 is shown. May be appropriately determined.
[0033]
Note that a multi-layer printed circuit board as a product will be described as a multi-layer substrate 100 having various forms during the manufacturing process by distinguishing a work in a manufacturing process for manufacturing the product.
[0034]
In FIG. 4A, reference numeral 21 denotes a single side having a conductive pattern 22 formed by etching a conductive foil (copper foil having a thickness of 18 μm in this embodiment) adhered to one side of a resin film 23 as an insulating base material. It is a conductor pattern film. In this embodiment, a 75 μm thick thermoplastic resin film composed of 65 to 35% by weight of a polyetheretherketone resin and 35 to 65% by weight of a polyetherimide resin is used as the resin film 23.
[0035]
As shown in FIG. 4A, when the formation of the conductor pattern 22 is completed, next, as shown in FIG. 4B, a carbon dioxide laser is irradiated from the resin film 23 side to bring the conductor pattern 22 into contact with the bottom surface. A via hole 24 as a bottomed via hole is formed. The via hole is formed by adjusting the output of the carbon dioxide gas laser, the irradiation time, and the like so that a hole is not formed in the conductor pattern 22.
[0036]
An excimer laser or the like can be used for forming the via hole 24 in addition to the carbon dioxide gas laser. A via hole forming method such as drilling other than laser is also possible, but it is preferable to perform drilling with a laser beam because a hole with a fine diameter can be formed and the conductor pattern 22 is hardly damaged.
[0037]
When the formation of the via hole 24 is completed as shown in FIG. 4B, the conductive paste 50 as an electrical connection material is filled in the via hole 24 as shown in FIG. 4C. The conductive paste 50 has an average particle size of 5 μm and a specific surface area of 0.5 m. ² / G of tin particles having an average particle size of 1 μm and a specific surface area of 1.2 m ² / G of silver particles and 300 g of terpineol, an organic solvent, obtained by dissolving 6 g of ethylcellulose resin, and kneaded by a mixer to form a paste.
[0038]
Here, the ethyl cellulose resin is added to impart shape retention to the conductive paste 50, and an acrylic resin or the like may be employed as the shape retention imparting agent.
[0039]
The conductive paste 50 is printed and filled in the via hole 24 of the one-sided conductive pattern film 21 by a screen printing machine using a metal mask, and then terpineol is dried at 140 to 160 ° C. for about 30 minutes. In this embodiment, a screen printer is used to fill the conductive paste 50 into the via hole 24. However, another method using a dispenser or the like is also possible as long as the filling can be surely performed.
[0040]
Here, it is possible to use other than terpineol as the organic solvent added for forming the paste, but it is preferable to use an organic solvent having a boiling point of 150 to 300 ° C. In the case of an organic solvent having a boiling point of less than 150 ° C., a problem that the change of the viscosity of the conductive paste 50 with the passage of time becomes large easily occurs. On the other hand, an organic solvent having a boiling point exceeding 300 ° C. is not preferable because the time required for drying is long.
[0041]
In the present embodiment, the metal particles constituting the conductive paste 50 have an average particle size of 5 μm and a specific surface area of 0.5 m. ² / G tin particles, average particle size 1 μm, specific surface area 1.2 m ² / G of silver particles, these metal particles have an average particle size of 0.5 to 20 μm and a specific surface area of 0.1 to 1.5 m. ² / G.
[0042]
The average particle size of the metal particles is less than 0.5 μm or the specific surface area is 1.5 m ² / G, a large amount of an organic solvent is required to form a paste having a viscosity suitable for filling via holes. A conductive paste containing a large amount of an organic solvent requires a long time for drying. If drying is insufficient, a large amount of gas is generated by heating during interlayer connection. Decreases connection reliability.
[0043]
On the other hand, the average particle size of the metal particles exceeds 20 μm or the specific surface area is 0.1 m. ² If the ratio is less than / g, it becomes difficult to fill the via holes 24, the metal particles are likely to be unevenly distributed, and it is difficult to form a conductive composition 51 made of a uniform alloy, which will be described later, even if heated. There is a problem that it is difficult to secure the property, which is not preferable.
[0044]
Before the conductive paste 50 is filled into the via hole 24, a portion of the conductive pattern 22 facing the via hole 24 may be thinly etched or reduced. According to this, via connection described later is performed more favorably.
[0045]
On the other hand, in FIG. 4 (d), reference numeral 31 denotes the formation of the conductor pattern 22 on the resin film 23 which is an insulating base material by the steps shown in FIGS. , A single-sided conductive pattern film in which via holes 24 are formed and conductive paste 50 is filled.
[0046]
When the via hole 24 shown in FIG. 4B is formed, the single-sided conductor pattern film 31 is formed with a laser processing to substantially match the outer shape of the element layer 41 at a position corresponding to the arrangement position of the incorporated element layer 41 described later. The through holes 35 having the same dimensions are formed. The dimensions of the through hole 35 are such that when the element layer 41 is inserted into the through hole 35, the clearance between the element layer 41 and the resin film 23 is 20 μm or more over the entire circumference of the element layer 41 and the resin film 23 Is preferably smaller than the thickness (75 μm in this example).
[0047]
The formation of the through hole 35 was performed by laser processing when forming the via hole 24. However, the through hole 35 may be formed by punching, router processing, or the like separately from the formation of the via hole 24.
[0048]
Here, as the resin film 23 of the single-sided conductor pattern film 31, in this embodiment, similarly to the resin film 23 of the single-sided conductor pattern film 21, 65 to 35% by weight of a polyetheretherketone resin and 35 to 65% of a polyetherimide resin are used. A 75-μm-thick thermoplastic resin film composed of% by weight is used.
[0049]
When the formation of the through-hole 35 in the single-sided conductor pattern film 31 and the filling and drying of the conductive paste 50 into the via holes 24 of the single-sided conductor pattern films 21 and 31 are completed, as shown in FIG. A plurality of films 21 and 31 (five in this embodiment) are laminated.
[0050]
At this time, the single-sided conductor pattern films 21 and 31 are laminated with the side on which the conductor pattern 22 is provided facing upward. That is, the single-sided conductor pattern films 21 and 31 are laminated such that the surface on which the conductor pattern 22 is formed and the surface on which the conductor pattern 22 is not formed face each other.
[0051]
Here, the single-sided conductive pattern film 31 provided with the through-hole 35 at the same position is formed so that the thickness of the space 36 formed by the through-hole 35 is substantially equal to or less than the thickness of an electric element 41 described later. A plurality of sheets (two sheets in this embodiment) are stacked adjacent to each other. In the present embodiment, since the thickness of the element layer 41 is 160 μm, two through holes 35 each having a size of 75 μm in the thickness direction are adjacent to each other so that the thickness of the space 36 is substantially equal to or less than this. (That is, so that the thickness of the space 36 becomes 150 μm).
[0052]
When the single-sided conductor pattern films 21 and 31 are laminated, a member having a function such as a resistor, a capacitor, a filter, or an IC is provided as an element layer 41 in a space 36 formed by the through hole 35. Or a material is inserted. It is preferable that the electrodes 42 are formed on both ends of the element layer 41 including the surfaces in the stacking direction of the single-sided conductor pattern films 21 and 31.
[0053]
Then, the conductive paste 50 is filled in the single-sided conductive pattern film 21 stacked above the space 36 in which the element layer 41 is inserted, at a position where the conductive pattern 22 and the electrode 42 can be electrically connected. Via holes 24 are arranged.
[0054]
After the single-sided conductor pattern films 21 and 31 are laminated as shown in FIG. 4 (e), pressure is applied from both upper and lower surfaces while heating with a vacuum heating press. In the present example, heating was performed at a temperature of 250 to 350 ° C. and pressure was applied at a pressure of 1 to 10 MPa for 10 to 20 minutes.
[0055]
As a result, as shown in FIG. 4F, the single-sided conductor film patterns 21, 31 and the heat sink 46 are bonded to each other. Since the resin films 23 are all formed of the same thermoplastic resin material, the insulating base material 39 is easily heat-sealed and integrated.
[0056]
Further, the conductive composition 51 integrated by sintering the conductive paste 50 in the via hole 24 makes the interlayer connection between the adjacent conductor patterns 22 and the connection between the electrode 42 of the element layer 41 and the conductor pattern 22. Then, a multilayer substrate 100 incorporating the element layer 41 is obtained. Here, the conductive composition 51 is an electrical connection material, and the via hole 24 and the conductive composition 51 constitute a via of the present embodiment.
[0057]
Here, the mechanism of interlayer connection of the conductor pattern 22 will be briefly described. The conductive paste 50 filled and dried in the via hole 24 is in a state where tin particles and silver particles are mixed. When the paste 50 is heated to 250 to 350 ° C., the melting point of the tin particles is 232 ° C., and the melting point of the silver particles is 961 ° C., so that the tin particles are melted and cover the outer periphery of the silver particles. Adheres to
[0058]
When heating is continued in this state, the molten tin starts to diffuse from the surface of the silver particles, forming an alloy of tin and silver (melting point: 480 ° C.). At this time, since a pressure of 1 to 10 MPa is applied to the conductive paste 50, the conductive composition 51 made of an alloy integrated by sintering is formed in the via hole 24 with the formation of the alloy of tin and silver. Is formed.
[0059]
When the conductive composition 51 is formed in the via hole 24, since the conductive composition 51 is pressurized, the conductive composition 51 is pressed against the surface of the conductive pattern 22 that forms the bottom of the via hole 24. As a result, the tin component in the conductive composition 51 and the copper component of the copper foil forming the conductor pattern 22 undergo solid phase diffusion to each other, and solid phase diffusion occurs at the interface between the conductive composition 51 and the conductor pattern 22. The layers are formed and electrically connected.
[0060]
The electrode 42 of the electric element 41 is formed by forming a tin plating layer or the like on the surface of a metal member such as copper or nickel, and is formed in the via hole 24 by a mechanism substantially similar to the above-described interlayer connection of the conductor pattern 22. The formed conductive composition 51 and the conductive pattern 22 via the solid phase diffusion layer formed at the interface between the conductive composition 51 and the conductive pattern 22 and at the interface between the conductive composition 51 and the electrode 42. Make an electrical connection.
[0061]
When the resin film 23 is heated while being pressed by the vacuum heating press, the elastic modulus of the resin film 23 is reduced to about 5 to 40 MPa. Therefore, the resin film 23 around the through hole 35 tends to be deformed so as to be pushed into the through hole 35. Further, the resin film 23 located in the film stacking direction of the through hole 35 also tends to be deformed so as to be extruded into the through hole 35. That is, the resin film 23 around the space 36 is extruded toward the space 36.
[0062]
Thereby, the element layer 41 is sealed by the insulating base material 39 integrated while the resin film 23 is deformed. In addition, it is preferable that the elastic modulus of the resin film 23 at the time of hot pressing is 1 to 1000 MPa. When the elastic modulus is larger than 1000 MPa, heat fusion between the resin films 23 is difficult, and the resin film 23 is hard to deform. On the other hand, if the elastic modulus is less than 1 MPa, the resin film easily flows under pressure, and it is difficult to form the multilayer substrate 100.
[0063]
Further, as described above, the through hole 35 formed in the resin film 23 has a clearance between the element layer 41 and the resin film 23 of 20 μm or more over the entire circumference of the element layer 41 and the thickness of the resin film 23 ( In this example, the size was set to be 75 μm or less. This is because when the clearance is less than 20 μm, it is difficult to insert the element layer 41 into the through hole 35, and when the clearance is larger than the thickness of the resin film 23, the electric element 41 is completely sealed even if the resin film 23 is deformed by hot pressing. This is because it is difficult to stop.
[0064]
Further, as described above, when the single-sided conductor pattern films 21 and 31 are laminated, the thickness of the space portion 36 (that is, the total thickness of the resin film 23 in which the through holes 35 are formed) is larger than the thickness of the element layer 41. The number of laminated single-sided conductor pattern films 31 having the through holes 35 was determined so as to be substantially equal to or less than the number.
[0065]
In the above-described manufacturing process, the step of forming the through hole 35 shown in FIG. 4D is the hole forming step in the present embodiment, and the step shown in FIG. The process and the base member forming process. The step of hot-pressing the laminate shown in FIG. 4E to form the multilayer substrate 100 shown in FIG. 4F is the bonding step in the present embodiment.
[0066]
According to the above-described manufacturing method and the configuration obtained by the manufacturing method, the built-in element layer 41 is positioned with respect to the insulating base material 39 to which the respective resin films 23 are securely bonded to each other, so that the conductive pattern 22 and the conductive pattern 22 are surely fixed. A multilayer substrate 100 that is electrically connected and securely sealed in the insulating base material 39 is obtained.
[0067]
(Second embodiment)
Hereinafter, other embodiments to which the present invention is applied will be described. In the following embodiments, the same or equivalent components as those of the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated.
[0068]
In the second embodiment, as shown in FIG. 5, at the lead-out terminal 70a connected to the ground layer 22g in the shield shield 70 described in the first embodiment, the lead-out terminal 70a extending from the shield shield 70 is provided. Instead of the terminal 70a, the ground layer 22g in the shield shielding part 70 may be exposed and directly exposed. FIG. 5 is a perspective view showing a schematic configuration of the multilayer printed board according to the embodiment, and is an exploded perspective view showing an assembling relationship with a metal case as a housing for housing the multilayer printed board.
[0069]
Of the upper lid 300a and the lower case 300b constituting the metal case 300 shown in FIG. 5, for example, the lower case 300b is screwed to the multilayer printed circuit board 1 with screws or the like. The upper lid 300a can be grounded by the pattern of the ground layer 22g formed in the shield shielding part 70, and the same effect as in the first embodiment can be obtained.
[0070]
(Third embodiment)
In the third embodiment, a configuration in which a material layer different from the laminated resin film 23 described in the first embodiment is inserted into the resin film 23 in the element layer 41 as a dielectric, which functions as a noise absorber. Instead, as shown in FIG. 6E, the laminated resin film 23 is used as a dielectric. 6A to 6E are cross-sectional views illustrating a method of manufacturing a multilayer printed circuit board according to the embodiment in a schematic manufacturing process. FIGS. 6A to 6E illustrate states of the multilayer printed circuit board in the manufacturing process. FIG.
[0071]
As shown in FIG. 6E, a capacitor that functions as a noise absorber can be formed only by forming the pair of conductor patterns 22a and 22b at positions facing each other with the resin film 23 interposed therebetween.
[0072]
Hereinafter, features of a manufacturing method relating to the multilayer printed board 1 (the work in the manufacturing process, the multilayer board 100) according to the third embodiment will be described with reference to FIGS. 6A to 6E.
[0073]
6A to 6C correspond to FIGS. 4A to 4C described in the first embodiment, respectively, and thus description thereof is omitted. .
Next, as shown in FIG. 6D, a plurality of single-sided conductor pattern films 21, 21a and 21b (five in this embodiment) are laminated.
[0074]
At this time, the single-sided conductor pattern films 21, 21a, and 21b to be laminated are laminated with the side on which the conductor pattern 22 is provided on the upper side. That is, the single-sided conductor pattern films 21, 21a, and 21b are laminated such that the surface on which the conductor pattern 22 is formed and the surface on which the conductor pattern 22 is not formed face each other.
[0075]
Here, in the present embodiment, the single-sided conductor pattern film 21 is laminated on one side so that a pair of conductor patterns 22a and 22b are arranged to face each other on both sides of the single-layered single-sided conductor pattern film 21a. The conductor foils on the conductor pattern films 21a and 21b are respectively patterned.
[0076]
As described above, in the present embodiment, the resin film 23 is composed of the polyetheretherketone resin and the polyetherimide resin. The dielectric constant of the resin film 23 is 3.3. Therefore, by arranging the pair of conductor patterns 22a and 22b on both sides of the resin film 23 so as to face each other, it is possible to form a capacitor using the resin film 23 as a dielectric and using the pair of conductor patterns 22a and 22b as electrodes. it can.
[0077]
The capacitance of the capacitor can be adjusted by the area of the pair of conductor patterns 22a and 22b arranged opposite to each other and the thickness of the resin film 23 sandwiched between the pair of conductor patterns 22a and 22b. That is, as the area of the pair of conductor patterns 22a and 22b is increased, or as the thickness of the sandwiched resin film 23 is reduced, the capacitance of the capacitor is increased. Therefore, a capacitor having a desired capacitance can be formed by the pair of conductor patterns 22a and 22b and the resin film 23.
[0078]
Here, it is preferable that the thickness of the resin film 23 sandwiched between the pair of conductor patterns 22a and 22b is formed smaller than the thickness of the other resin films 23 forming the multilayer substrate 100. As described above, as the thickness of the resin film 23 sandwiched between the pair of conductor patterns 22a and 22b decreases, the capacitance of the capacitor with respect to the conductor patterns 22a and 22b having the same area increases. Therefore, by forming the capacitor using the resin film 23 which is thinner than the other resin films 23 forming the multilayer substrate 100, the adjustment width of the capacitance can be increased.
[0079]
The reason why the other resin film 23 for forming the multilayer substrate 100 should be formed thicker than the resin film 23 for forming the capacitor is as follows. That is, in the multilayer substrate 100 of the present embodiment, the conductor patterns 22, 22a, and 22b are formed and laminated on the plurality of resin films 23, and are adhered to the adjacent resin films 23 by plastic deformation of the resin films 23. . Therefore, when the thickness of the resin film 23 is small, the deformation of the resin film becomes insufficient, and it becomes impossible to obtain a sufficient adhesive strength.
[0080]
After the single-sided conductor pattern films 21, 21a, 21b are laminated as shown in FIG. 6 (d), pressure is applied while heating from above and below both sides using a vacuum heating press (not shown). In this embodiment, the pressure was increased to 1 to 10 MPa for 10 to 20 minutes while heating to a temperature of 250 to 350 ° C.
[0081]
As a result, as shown in FIG. 6E, the resin films 23 of the single-sided conductor film patterns 21, 21a, 21b are plastically deformed and adhered to each other. Since the resin films 23 are all formed of the same thermoplastic resin material, the insulating base material 39 is easily heat-sealed and integrated.
[0082]
Further, the conductive paste 50 in the via hole 24 is sintered to form the integrated conductive composition 51, and is further diffusion bonded to the adjacent conductive pattern 22. Thereby, interlayer connection between adjacent conductor patterns 21 is performed. Through these steps, a multilayer substrate 100 having a built-in capacitor 43 constituted by the pair of conductive patterns 22a and 22b and the resin film 23 is obtained.
[0083]
According to the above manufacturing process, when patterning the conductor pattern 22 from the conductor foil, the conductor patterns 22a and 22b for forming the capacitor 43 can be formed at the same time. Therefore, when forming the conductor patterns 22a and 22b to be the electrodes of the capacitor 43 corresponding to the element layer 41 of the first embodiment, no additional process is required. Furthermore, since the dielectric of the capacitor 43 uses the resin film 23 which is an insulating base material for forming the multilayer substrate 100, no additional configuration or method is required for obtaining the dielectric.
[0084]
Then, the stacked single-sided conductor pattern films 21, 21a, 21b are integrated by the heating / pressing process, thereby completing the formation of the capacitor 43. As described above, according to the present embodiment, the multilayer substrate 100 with the built-in capacitor 43 can be formed simply by aligning and disposing the pair of conductor patterns 22a and 22b on both sides of the resin film 23. .
[0085]
In the present embodiment, a conductor pattern 22a to be one electrode of the capacitor 43 is formed at a position separated from the mounting surface 60 of the electronic component 90 by one layer of the resin film 23, and the other conductor pattern 22b is It is provided at a position facing one conductive pattern 22a with only one layer of resin film 23 interposed therebetween. Thus, the capacitor 43 is provided below and near the electronic component 90 to which the capacitor 43 is to be connected, similarly to the element layer 41 described in the first embodiment.
[0086]
In particular, in the present embodiment, the electronic component 90 and the capacitor 43 are connected to the inside of the multilayer substrate 100 substantially only through the conductive composition 51. As described above, the conductive composition 51 is an alloy of tin and silver, and is filled in the via hole 24 having a diameter of 50 to 100 μm. For this reason, the conductivity of the conductive composition 51 is higher than that of the conductive pattern 22. For this reason, by connecting the electronic component 90 and the capacitor 43 substantially only through the conductive composition 51, it is possible to prevent an increase in the resistance value in a wiring path between the electronic component 90 and the capacitor 30. This can also improve the characteristics of the transmitted signal.
[0087]
In the first embodiment described above, the thickness of the resin film 23 forming the capacitor together with the pair of conductor patterns 22a and 22b is made smaller than the thickness of the other resin films 23, thereby adjusting the capacitance of the capacitor. Increased width. However, the same effect can be obtained by making the dielectric constant of a resin film for forming a capacitor higher than that of another resin film.
[0088]
In order to increase the dielectric constant of the resin film forming the capacitor, for example, a powder (filler) such as barium titanate, lead titanate, barium tungstate may be mixed only into the resin film forming the capacitor. When the dielectric constant of the resin film is increased to 4 or more in this way, a large-capacity capacitor can be formed as a capacitor built in the multilayer substrate.
[0089]
Thus, the only resin film that increases the dielectric constant is the resin film that functions as a dielectric of the capacitor. Then, by bonding a metal foil made of copper, iron, tungsten, nickel, cobalt, zinc, or lead on one or both sides of a resin film having a high dielectric constant, which has a higher resistance value than copper, a multilayer substrate having a built-in capacitor. Can be formed. When the metal foil adhered to the resin film is a metal foil having a low resistance value, such as copper, the metal foil is removed by, for example, an etching method or the like except for a region serving as a capacitor electrode and a region serving as a wiring. On the other hand, when a metal foil having a high resistance value is used, the metal foil is removed leaving only a region used as a capacitor electrode or a land for interlayer connection.
[0090]
Further, the type of the resin film itself may be changed, and only the resin film forming the capacitor may be formed of a thermoplastic resin having a higher dielectric constant than other resin films.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a multilayer printed circuit board according to a first embodiment of the present invention.
FIG. 2 is a plan view showing a multilayer printed circuit board before bending a shield shielding part in FIG. 1;
FIG. 3 is a cross-sectional view showing a configuration around an element layer as a noise absorber in FIG. 1;
FIGS. 4A to 4G are cross-sectional views illustrating a method for manufacturing a multilayer printed circuit board according to the first embodiment in a schematic manufacturing process, wherein FIGS. It is sectional drawing which shows the state of a board | substrate.
FIG. 5 is a perspective view showing a schematic configuration of a multilayer printed board according to a second embodiment, and is an exploded perspective view showing an assembling relationship with a metal case as a housing for housing the multilayer printed board.
FIGS. 6A to 6E are cross-sectional views showing a method of manufacturing a multilayer printed circuit board according to the third embodiment in a schematic manufacturing process, and FIGS. 6A to 6E are multilayer printing in the manufacturing process. FIG. 3 is a schematic cross-sectional view showing a state of a substrate.
[Explanation of symbols]
1 multilayer printed circuit board
21, 31 Single-sided conductor pattern film
22 Conductor pattern
22g Ground layer
23 Film (resin film)
24 Via holes (bottomed via holes, part of vias)
35 Through hole
36 space
39 Insulating base material
41 Element layer (electric element)
42 electrodes
46 Noise conductor
47 Through Hole
50 Conductive paste (interlayer connection material)
51 Interlayer composition (conductive composition)
70 Shield shield
70a slit
70b Terminal for conduction
80 Connector
80a Wiring terminal
100 Multilayer substrate (during manufacturing)
300 metal case

Claims (6)

A conductor pattern film in which a conductor pattern is formed on at least one surface of a film made of a thermoplastic resin, and a plurality of resin films including the conductor pattern film are laminated and pressed while heating, so that the resin films are mutually bonded. In a multilayer printed circuit board that is bonded and multilayered,
An element layer disposed on the inner layer side of the plurality of laminated resin films and functioning as a noise absorber; a ground layer formed in the direction in which the element layers are laminated, and formed of the conductor pattern; A multi-layer printed circuit board, comprising: a noise conductor portion connected to the substrate for guiding noise; and a shield shielding portion made of the plurality of laminated resin films forming a substrate region near the noise conductor portion. 2. The multilayer printed circuit board according to claim 1, wherein the shield shielding portion is provided with a slit for bending or rolling the plurality of laminated resin films. 3. The multilayer printed circuit board according to claim 1, wherein a conduction terminal connected to the ground layer extends from the shield shielding portion. The multilayer printed circuit board according to claim 3, further comprising a metal case forming a housing that houses the multilayer printed circuit board,
The multilayer printed circuit board, wherein the metal case is accommodated by sandwiching the multilayer printed circuit board, and is electrically connected to the conduction terminal. The said noise conductor part is provided with the said conductor pattern laminated | stacked on the outer side of the said element layer and the said ground layer, and the through-hole electrically connected to the said conductor pattern and the said element layer, The claim The multilayer printed board according to any one of claims 1 to 4. The surface of the multilayer printed circuit board according to any one of claims 1 to 5, wherein the surface is a mounting surface of an electronic component,
The multilayer printed circuit board, wherein the element layer is provided below and near an electronic component to which the element layer is to be connected.

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