JP2009126115A - Laminated sheet and product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate damage caused by short circuit and removal of de-lamination of a resin layer and also to get an electromagnetic wave shielding property. <P>SOLUTION: A metal mesh 25 obtained by weaving an electric conductive fiber material is used as a metal core (core material 21) of a printed wiring board 11 having a metal core structure, whereby deposition for making rough which causes damage by a short circuit is eliminated and also tight adhesion between the metal mesh 25 and a resin is increased, and also an electromagnetic wave shielding property can be obtained by using the metal mesh 25 as an electromagnetic wave shielding layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printed wiring board having heat dissipation, and more particularly, to a printed wiring board and its components that can achieve high performance without short circuit defects and delamination.

  As a printed wiring board having heat dissipation, there is a printed wiring board having a metal core structure having a copper plate as a core (core material). This type of printed wiring board is manufactured through a process as shown in FIG.

  First, a base plate 101 is obtained by cutting a copper plate having a predetermined thickness as a core into a predetermined large predetermined shape (see FIG. 16A). Subsequently, a drilling process is performed to open the through hole 102 at a predetermined position of the base material 101 (see FIG. 16B).

  Next, a roughening process is performed on the surface of the perforated base material 103 by the method disclosed in Patent Document 1 (see FIG. 16C). In this roughening treatment, a dendritic copper electrodeposition layer is formed by electrolytic plating, and then the dendritic copper is changed to bumpy copper 101a by electrolytic treatment.

  Thereafter, as shown in Patent Document 2 below, the prepreg 104 and the copper foil 105 are stacked on both surfaces of the perforated base material 103 after the roughening treatment (see FIG. 16D), and these are laminated by hot pressing. They are integrated (see FIG. 16 (e)). That is, the copper foil 105 exists on both surfaces of the perforated base material 103 via the resin layer 104a. This is the copper clad laminate 106.

  Next, through holes 107 are formed at predetermined positions (see FIG. 16 (f)), and thereafter, necessary processing such as through-hole plating 108, pattern 109 formation, solder resist 110 is performed, and a printed wiring board having a metal core structure. 111 is obtained (see FIG. 16G).

JP 2005-353920 A Japanese Unexamined Patent Publication No. 64-89592

  The roughening treatment for the perforated substrate is indispensable and important for improving the adhesion between the metal core and the resin layer. However, when the roughening treatment is performed by the method as described above, the current concentrates around the through hole of the base material, so that dendritic copper adheres preferentially to that part, and as a result, a hump-like shape around the through hole Copper 101a is largely deposited.

  For this reason, at the time of subsequent hot pressing, when the resin of the prepreg flows into the through hole, the bump-shaped copper 101a may be peeled off to become a burr 101b and be released into the resin in the through hole 102 ( (Refer FIG.16 (e)).

  In such a state, if the through-hole 107 is drilled and the through-hole plating 108 is applied, the burr 101b comes into contact with the through-hole plating 108 and a short circuit failure occurs.

  Moreover, in the printed wiring board of the metal core structure which has a copper plate which has electroconductivity as a base (core material), it is possible to use the copper plate as a core as a shielding material for electromagnetic wave shielding. However, if the metal base is used as an electromagnetic shielding material, there is a drawback that the weight of the device becomes heavy.

  In view of this, the main object of the present invention is to prevent short circuit defects and delamination of the resin layer. It is another object of the present invention to make it possible to use a conductive core material as an electromagnetic shielding material.

  Means therefor is a laminate having a conductive layer on a resin layer, and a laminate in which a porous and conductive sheet-like core material is provided as a core inside the resin layer. .

  Another means is a laminated plate having a conductive layer on the resin layer, and is porous and conductive having a space extending in the surface direction within the thickness and opening on both the front and back surfaces inside the resin layer. It is a laminated board provided with a sheet-like core material having properties as a core.

  Said core material is good in it being formed with the metal mesh.

  Another means is a printed wiring board in which a wiring pattern is formed of a conductive layer in the above laminated board.

  As described above, according to the present invention, the core material as the core is a porous sheet formed of a metal mesh or the like, and the molten resin at the time of hot pressing performed by laminating prepregs forms porous holes. Since it is possible to enter the space, the resin layers can be integrated without a separate roughening treatment. For this reason, it is possible to prevent a conventional short circuit failure from occurring.

  Further, depending on the degree of porosity, the anchor effect necessary for the product can be obtained, the adhesion can be improved, and the occurrence of delamination can be eliminated.

  Furthermore, since the core material has electrical conductivity, not only it has heat dissipation properties but also electromagnetic wave shielding properties can be obtained.

An embodiment for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a printed wiring board 11 having a metal core structure, FIG. 2 is a schematic view showing a manufacturing process thereof, and FIG. 3 is a core material 21 used as a metal core and a copper-clad laminate using the core material 21. 4 is a cross-sectional view of the plate 41, and FIG.

  As shown in these figures, a sheet-like core material that is porous and conductive inside the resin layer 31a is used for the purpose of preventing short circuit defects and delamination of the resin layer 31a. This is realized with a configuration in which 21 is provided as a core.

  The core material 21 is composed of conductive metal meshes 25 and 26 and punching metal (not shown), and the entire core material 21 is a conductive portion (see FIGS. 1 and 5) having conductivity. However, the plated coatings 27b and 28b formed on the surface of the non-conductive woven fabric 28a and the nonwoven fabric 27a are formed, and only the plated coatings 27b and 28b are conductive portions (see FIGS. 7 and 9). There may be.

  The space for forming the porous holes is not a single foam but a continuous foam, and is a space that smoothly enters when molten resin flows from both the front and back surfaces of the core material 21. More preferably, the core material 21 communicates on the front and back sides, or has a spread in the surface direction within the thickness of the core material 21 and opens on both front and back surfaces.

This will be specifically described below.
FIG. 1 is a cross-sectional view showing a printed wiring board 11 having a metal core structure. As shown in FIG. 1, a core portion, that is, a core material 21 is composed of a metal mesh 25 made of a conductive metal wire. . FIG. 2 is a schematic representation of the manufacturing process of such a printed wiring board 11. In this figure, the core material 21 is represented by a broken line. In order to manufacture, the sheet-like material 21a (see FIG. 2 (a)) is cut and drilled (see FIG. 2 (b)), the laminated integration process (see FIGS. 2 (c) and (d)), and the through hole. A desired printed wiring board 11 (see FIG. 2 (f)) is obtained through a formation process (see FIG. 2 (e)) and necessary steps (not shown) such as through-hole plating and pattern formation. It is done.

  The above-described cutting and drilling step is a step of cutting the material 21a into a predetermined size and shape determined in advance and opening the through holes 22 at necessary positions. The through hole 22 is made by an appropriate means such as die processing using a die and a punch or drilling depending on the material, and thereby a perforated base material as the core material 21 is obtained.

  The lamination and integration step is a step in which the prepreg 31 and the copper foil 32 are sequentially superposed on both surfaces of the core material 21 (a perforated base material for which the drilling has been completed), and hot pressing is performed. The hot press is performed by applying heat and pressure in a vacuum atmosphere, filling the melted resin of the prepreg 31 into the through-holes 22 of the core material 21 and the like, thereby achieving close contact between the resin and the core material 21. By this lamination integration, a copper-clad laminate 41 in which the resin layer 31a and the copper foil 32 as the conductive layer are disposed on both surfaces of the core material 21 is obtained. A part of the copper foil 32 becomes a pattern 32a later.

  The through hole forming step is a step of forming a hole (through hole 42) having a smaller diameter than the through hole 22 at a position corresponding to the required through hole 22 among the through holes 22 of the core member 21. When conductivity is imparted to the inner surface of the through hole 43 by the hole plating 43 (see FIG. 2F), the front and back copper foils 32 can be electrically connected.

  FIG. 3 is an explanatory view showing the manufacturing process until the material 21a made of the porous metal mesh 25 composed of metal wires is made into the copper-clad laminate 41. FIG. More specifically, as shown in FIG. 4, a material 21a (see FIG. 3A) made of a metal mesh 25 woven in a lattice shape is cut into a predetermined shape and penetrated into a predetermined position. The hole 22 is formed (see FIG. 3B). Subsequently, the prepreg 31 and the copper foil 32 are sequentially stacked on both surfaces of the core material 21 which is a perforated base material, and heat pressing is performed to integrate them all to obtain a copper-clad laminate 41 (FIG. 3C). (See (d)).

  In this integration, the resin of the prepreg melted by heat flows into the mesh of the metal mesh 25 as well as the through holes 22, and the inflowed resin fills the gaps between the metal wires. They are connected from both sides and are integrated with the core material 21 interposed.

  The metal mesh 25 is porous and its mesh (a space for forming a porous hole) extends in the surface direction within the thickness of the metal mesh 25 and opens on both the front and back surfaces. For this reason, the resin that has entered the mesh is like a piece that has been removed and can be integrated with a high anchor effect.

  In addition, the spread of the resin to the side is suppressed, the resin plate does not have a void due to the lack of resin, and the thickness becomes uniform. In such a copper-clad laminate 41, the core material 21, the resin layer 31a, and the copper foil 32 are formed in this order from the inside toward the outside.

Since the core material 21 can also be comprised with another material, another some example is demonstrated using FIGS. 5-10.
5 and 6 are examples of a printed wiring board 11 using a porous metal mesh 26 made of expanded metal as a core material 21 as another example of a conductive metal mesh. That is, as shown in FIG. 5, the printed wiring board 11 is manufactured using a copper-clad laminate 41 configured by wrapping the entire metal mesh 26 made of expanded metal with a resin. As shown in FIG. 6, the material 21a (see FIG. 6 (a)) made of a metal mesh 26 having a rhombus mesh is cut into a predetermined shape and a through hole 22 is formed at a predetermined position. (See FIG. 6B). Subsequently, the prepreg 31 and the copper foil 32 are sequentially stacked on both surfaces of the core material 21 which is a perforated base material, and hot pressing is performed to integrate them all to obtain a copper-clad laminate 41 (FIG. 6C). (See (d)).

  In this integration, the resin of the prepreg melted by heat flows into the rhombus mesh as well as the through-holes 22, and the inflowed resin fills all the gaps of the core material 21. They are connected from both sides and are integrated with the core material 21 interposed.

  The metal mesh 26 made of expanded metal is porous and its mesh (a space for forming a porous hole) extends in the surface direction within the thickness of the metal mesh 25, and is open on both the front and back surfaces. For this reason, the resin that enters the mesh of the metal mesh 26 is entangled with the inclined line portion forming the mesh, and high integrity is obtained. Further, as in the example of FIG. 3, the spread of the resin to the side is suppressed, the void of the resin plate due to insufficient resin content does not occur, and the thickness becomes uniform.

  FIGS. 7 and 8 are examples of the printed wiring board 11 using the sheet material 27 whose surface is subjected to conductive plating as the core material 21. That is, as shown in FIG. 7, the printed wiring board 11 is a copper-clad laminate 41 configured by enclosing a sheet material 27 having a conductive plating film 27 b on the surface of a rough nonwoven fabric 27 a with a resin. It is manufactured using. As the non-woven fabric 27a, an appropriate material can be used, but from the point of strength, a glass fiber can be preferably used. As shown in FIG. 8, the production is performed by cutting the material 21a (see FIG. 8A) made of the sheet material 27 having the plating film 27b formed on both the front and back surfaces of the nonwoven fabric 27a into a predetermined large predetermined shape, A through hole 22 is formed at the position (see FIG. 8B). Subsequently, the prepreg 31 and the copper foil 32 are sequentially stacked on both surfaces of the core material 21 which is a perforated base material, and are subjected to hot pressing to integrate them all to obtain a copper-clad laminate 41 (FIG. 8C). (See (d)).

  In this integration, the resin of the prepreg 31 melted by heat flows into the through hole 22 and also enters the space in the porous hole non-woven fabric 27a. The resin that has flowed into the through holes 22 and the space is connected from both the front and back surfaces in a state where all the through holes 22 of the core material 21 are filled, and is integrated with the core material 21 interposed.

  FIG. 9 and FIG. 10 show another example of the printed wiring board 11 using the sheet material 28 whose surface is subjected to conductive plating as a core material. That is, as shown in FIG. 9, the printed wiring board 11 includes a copper sheet formed by wrapping an entire sheet material 28 having a conductive plating film 28 b on a surface of a porous or rough woven fabric 28 a with a resin. Manufactured using a tension laminate 41. As the woven fabric 28a, an appropriate one can be used, but one made of glass fiber can be suitably used from the viewpoint of strength. Further, the woven fabric 28a may be a mesh-like one or a mesh-free one. As shown in FIG. 10, the material 21a (see FIG. 10A) made of the sheet material 28 in which the plating film 28 b is formed on both the front and back surfaces of the woven fabric 28 a is cut into a predetermined large predetermined shape, A through hole 22 is formed at a predetermined position (see FIG. 10B). Subsequently, the prepreg 31 and the copper foil 32 are sequentially stacked on both surfaces of the core material 21 which is a perforated base material, and heat pressing is performed to integrate them all to obtain a copper-clad laminate 41 (FIG. 10C). (See (d)).

  In this integration, the resin of the prepreg 31 melted by heat flows into the through-hole 22 and, when having a mesh, also flows into the space that is the mesh and the space between the fibers. The resin that has flowed into the through holes 22 or the mesh is connected from both the front and back surfaces in a state where all the through holes 22 of the core material 21 are filled, and is integrated with the core material 21 interposed.

  In the above example, the copper clad laminate 41 and the printed wiring board 11 provided with one core material 21 have been described. However, a plurality of core materials 21 may be provided. For example, as shown in FIG. 11, a copper-clad laminate 41 and a printed wiring board 31 having two core members 21 are obtained by sandwiching a prepreg 31 between two core members 21 and 21. be able to.

  In the case where a plurality of core materials 21 are provided, and the core material is made of the metal mesh 25 as shown in FIG. 12, the metal meshes 25 may be joined in advance. The joining can be easily performed by appropriate means such as spot welding 25a. By joining, position shift at the time of hot pressing can be prevented.

  Further, in the above example, the double-sided wiring is described using the printed wiring board 11 having the metal core structure, but the printed wiring board 11 having the single-sided wiring structure can also be configured as shown in FIG. 13A shows an example in which a metal mesh 25 made of a metal wire is used as the core material 21, FIG. 13B shows an example in which a metal mesh 26 made of an expanded metal is used as the core material 21, and FIG. ) Is an example in which a sheet material 27 made of a non-woven fabric with plating is used as the core material 21, and FIG. 13D is an example in which a sheet material 28 made of a woven fabric with plating is used as the core material 21. About the same part as the above-mentioned structure, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.

  As described above, when the copper clad laminate 41 is manufactured, the conventional roughening process for the core material 21 is not necessary. Since the roughening treatment is not performed, the copper plating formed by the roughening treatment is peeled off, and this does not become a burr and cause a short circuit failure.

  In addition, since the core material 21 is formed in a porous shape, adhesion with the resin can be obtained, and the occurrence of delamination can be eliminated.

  Moreover, it can be made lighter than when a metal plate is used, and is useful for in-vehicle use. In addition, since the material itself has electrical conductivity, it is possible to obtain appropriate heat equalization / heat dissipation properties and electromagnetic wave shielding properties.

  Regarding the electromagnetic wave shielding property, the frequency band of the electromagnetic wave to be shielded can be changed by setting conditions such as the eye size of the core material 21. In addition to enhancing the shielding effect by stacking a plurality of core materials 21, it is possible to shield electromagnetic waves in a wider frequency band by combining those having different frequency bands of the electromagnetic waves to be shielded.

  Using the printed wiring board manufactured as described above as a sample, an experiment was conducted to test the electromagnetic shielding effect. The experiment is a first test (see FIG. 14) in which a metal mesh made of copper wire is used as a sample to test the difference in shielding effect depending on the size of the eye, and the shielding effect when the materials constituting the metal mesh are different. A second test (see FIG. 15) was conducted to test the difference.

  In the experiment, the shielding effect against electromagnetic waves in the frequency band of 10 MHz to 10 GHz was examined using the KEC (Kansai Electronics Industry Promotion Center) method. In addition, as shown in FIG. 4, the wire diameter d is the thickness of a metal wire, and the opening w is the space | interval between metal wires.

  According to the results of the first experiment, it can be seen that the smaller the opening, the higher the electromagnetic shielding effect (see FIG. 14).

  According to the result of the second experiment, it can be seen that the electromagnetic wave shielding property varies depending on the material even if the wire diameter and the opening are the same (see FIG. 15). Moreover, it turns out that it is preferable to use copper and silver as a conductive metal.

In correspondence between the configuration of the present invention and the configuration of the above-described embodiment,
The conductive layer of the present invention corresponds to the copper foil 32 described above,
Similarly,
The laminate corresponds to the copper clad laminate 41,
The present invention is not limited to the above-described configuration, and other forms can be adopted.
For example, the conductive layer and the core material can be formed of a material other than copper.

Sectional drawing of a printed wiring board. The schematic diagram of the manufacturing process of a printed wiring board. Explanatory drawing of the manufacturing process of a laminated board. The top view of the core material which consists of a metal mesh comprised with the metal wire. Sectional drawing of a printed wiring board. Explanatory drawing of the manufacturing process of a laminated board. Sectional drawing of a printed wiring board. Explanatory drawing of the manufacturing process of a laminated board. Sectional drawing of a printed wiring board. Explanatory drawing of the manufacturing process of a laminated board. Explanatory drawing which shows the structure of the copper clad laminated board which concerns on another example. Sectional drawing which shows the structure of the core material which concerns on another example. Sectional drawing of the printed wiring board which concerns on another example. The table | surface which shows the electromagnetic wave shielding effect by the difference in opening. The table | surface which shows the electromagnetic wave shielding effect by the difference in material. Explanatory drawing which shows the manufacturing process of the conventional printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Printed wiring board 21 ... Core material 25, 26 ... Metal mesh 27a ... Non-woven fabric 28a ... Woven cloth 27b, 28b ... Plating film 31a ... Resin layer 32 ... Copper foil 41 ... Copper-clad laminate

Claims (4)

A laminate having a conductive layer on a resin layer,
A laminate in which a porous sheet-like core material is provided as a core inside the resin layer. A laminate having a conductive layer on a resin layer,
A laminated board in which a porous and conductive sheet-like core material having a space extending in the surface direction within the thickness and having openings opened on both front and back surfaces is provided as a core inside the resin layer. The laminate according to claim 1 or 2, wherein the core material is formed of a metal mesh. The printed wiring board by which the wiring pattern was formed with the conductive layer in the laminated board as described in any one of the said Claims 1-3.

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