JP2005064110A - Member for electronic component and electronic component using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain the high adhesion between copper foil and an organic material regarding a member for the electronic component comprised of a conductor and an organic dielectric, and the electronic component using the same. <P>SOLUTION: A heat-resistant plated coating with a thickness of 0.005-0.8 μm made of a zinc-nickel system or the like is formed on the surface of the low profile copper foil, which is roughened so as to make the surface roughness of the copper foil to be in the range of 0.3-3.5 μm by plating or the like. An olefinic silane coupling agent is applied on the surface of the heat-resistant plated coating. A thermosetting material made of vinylbenzyl (or its derivative) or vinylnaphtalene (or its derivative) is adhered on the that by high-temperature press or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic component member composed of a conductor and an organic dielectric, and an electronic component using the same.

In recent years, multilayer printed boards and build-up boards have been widely used to form highly integrated electronic circuits.
A multilayer printed circuit board was obtained by forming a copper-clad plate by stretching a copper foil on one or both sides of a dielectric prepreg, and forming a circuit by patterning the copper foil on the copper-clad plate. It is generated by laminating a plurality of copper-clad plates. The prepreg is formed, for example, by impregnating a base material made of glass cloth or aramid with an organic material such as a resin. As a method of stretching the copper foil on the surface of the prepreg, for example, there is a method of heating the copper foil and pressurizing (high temperature pressing) the surface of the prepreg.

  On the other hand, the build-up board is pre-patterned into a shape that constitutes a circuit, and an organic material such as resin is applied to the copper foil to form a resin-coated copper foil, and the formed resin-coated copper foil is laminated. It is created by doing.

  Various characteristics are required for the copper foil used for the production of multilayer printed boards and build-up boards. For example, since copper foil and a prepreg do not peel easily, copper foil needs to maintain high adhesiveness with the organic material which comprises a prepreg. It is also necessary to have high heat resistance so that peeling does not occur due to temperature changes caused by soldering or reflow. It is also necessary to have high chemical resistance so that it does not react with the organic material constituting the prepreg and cause peeling.

  On the other hand, electrical characteristics required for the copper foil include a low transmission loss, a high signal propagation speed, and a characteristic impedance being controlled to a desired value. In recent years, multilayer printed circuit boards and build-up boards are often used in devices (for example, portable terminals) including high-frequency circuits that handle high frequencies exceeding 1 [GHz], and thus their electrical characteristics are particularly emphasized. ing.

Therefore, various configurations have been conventionally considered in order for the copper foil to satisfy such various characteristics. For example, in order to improve the adhesion to the prepreg, the copper foil usually has a roughened adhesive surface with the prepreg (the roughened surface is referred to as the “M surface” or “roughened surface”). . There is also a method of forming a brass layer on the M surface of the copper foil in order to improve the heat resistance and chemical resistance of the copper foil (see, for example, Patent Document 1).
Japanese Patent Publication No. 51-35711

  Further, as shown in Equation 1, it is known that the magnitude of the transmission loss of the transmission line formed by the printed circuit board is proportional to the square root of the dielectric constant of the dielectric material constituting the printed circuit board and the dielectric loss tangent of the dielectric material. It has been. Further, as shown in Formula 2, it is known that the propagation speed of the signal propagating on the printed board is inversely proportional to the square root of the dielectric constant of the dielectric constituting the printed board.

(Equation 1)
A = k · f · (ε _r ) ^1/2 · tan δ
(Where A is the transmission loss, k is the coefficient, f is the frequency of the signal, ε _r is the dielectric constant of the dielectric, and tan δ is the dielectric loss tangent of the dielectric)

(Equation 2)
V = K · c / (ε _r ) ^1/2
(Where V is the signal propagation speed, K is the coefficient, and c is the speed of light)

Therefore, in order to reduce the transmission loss of the copper foil and improve the propagation speed, the dielectric constant and dielectric loss tangent of the prepreg as a dielectric may be reduced. From this viewpoint, a method of forming a prepreg using a bismaleimide triazine resin, a cyanate ester resin, a polyphenylene oxide resin, or the like, which is an organic material having a low dielectric constant or dielectric loss tangent, has been considered. From the same viewpoint, a method using a polyvinyl benzyl ether resin having a small dielectric constant or dielectric loss tangent as a substrate material is also considered (see, for example, Patent Document 2 and Patent Document 3).
JP 2001-181460 A JP 2001-247733 A

  Further, as shown in Equation 3, the characteristic impedance of the transmission line formed by the printed circuit board is determined by the dielectric constant of the dielectric constituting the printed circuit board, the thickness between the ground layers, the line width of the copper foil, and the thickness of the copper foil. It is known.

(Equation 3)
Z = {60 / (ε _r ) ^1/2 } · ln {(4 · w _GND ) / (0.567 · w _L ) + (0.6 · t)}
(Where Z is the characteristic impedance of the transmission line, w _GND is the thickness between the ground layers, w _L is the line width of the copper foil, and t is the thickness of the copper foil)

  Therefore, in order to stabilize the characteristic impedance of the transmission line formed by the printed circuit board, it is necessary to keep the dielectric constant of the prepreg and the thickness of the coated organic material constant. From this point of view, a method of forming a prepreg using an organic material having a small dielectric constant and hardly causing unevenness in the thickness of the coating film has been considered.

However, when the above-described method is used, there is a problem that other characteristics are greatly sacrificed in order to improve one characteristic.
For example, the above-mentioned organic material having a small dielectric constant and dielectric loss tangent that is effective in reducing transmission loss is generally configured to have a molecular structure in which polar groups are minimized. For this reason, these organic materials tend to have poor peel strength with respect to the copper foil and have poor adhesion compared to general organic materials for printed circuit boards (for example, FR-4).

  Further, when the copper foil is roughened to improve the adhesion to the prepreg, there is a problem that transmission loss in the high frequency region increases due to the skin effect. The skin effect is a phenomenon in which the higher the frequency of the current passing through the conductor, the more the current flows in the vicinity of the surface of the conductor, and the apparent conductivity of the conductor decreases. In the case of copper, when the frequency of the current is f [GHz], a portion where the depth from the surface is deeper than the skin depth value D [μm] shown in Formula 4 is substantially due to the skin effect. It is known that no current flows in

(Equation 4)
D = 2.09 / {(f · σ) ^1/2 }
(Where σ is the specific conductivity of copper)

  The roughness of the surface of the M surface of the electrolytic copper foil is usually about 4 to 8 [μm]. On the other hand, according to Equation 4, when the current frequency is 5 [GHz], the skin depth D is 0.93 [μm]. Further, even if the current frequency is 1 [GHz], the skin depth D is still 2.09 [μm]. Therefore, when the signal frequency is 1 [GHz] or higher, the roughness of the M surface of the electrolytic copper foil exceeds the skin depth value D, which leads to an increase in transmission loss.

  As a technique for suppressing an increase in transmission loss in the high frequency region due to the roughening of the copper foil, it is conceivable to use a low profile copper foil in which the roughness of the M plane is suppressed. The low profile copper foil is easy to ensure the accuracy of etching (patterning), so it is advantageous for stabilizing the characteristic impedance, and responds to the demand for miniaturization and high integration of the circuit by applying fine processing. You can also.

However, the low profile copper foil is inferior in adhesiveness with the organic material constituting the prepreg as a dielectric, and it is difficult to ensure a sufficient peel strength especially with the above-mentioned organic material having a small dielectric constant and dielectric loss tangent. . As a technique for improving the adhesive strength of the low profile copper foil, although a technique for applying a silane coupling treatment to the M surface has been proposed (see, for example, Patent Documents 4 to 6), all of the effects are insufficient. .
Japanese Patent Publication No. 2-19994 JP 63-183178 A JP-A-2-26097

  This invention is made | formed in view of the said actual condition, and aims at keeping high adhesive force between copper foil and an organic dielectric.

In order to achieve the above object, an electronic component member according to the first aspect of the present invention is provided.
Copper foil,
A heat-resistant plating film having a thickness of 0.005 to 0.8 μm formed on the surface of the copper foil;
An organic dielectric formed on the surface of the heat-resistant plating film and having a vinylbenzyl compound or a vinylnaphthalene compound;
It is characterized by providing.

  An electronic component member having such a structure is an organic material having a heat-resistant plating film having a thickness of 0.005 to 0.8 μm formed on the surface of the copper foil, and a vinylbenzyl compound or a vinylnaphthalene compound on the surface of the heat-resistant plating film. Since the dielectric is formed, even if the copper foil is a low profile copper foil, the copper foil can maintain high adhesion with the organic dielectric.

  The heat-resistant plating film is made of at least one material selected from zinc, zinc-tin, zinc-nickel, zinc-cobalt, copper-zinc, copper-nickel-cobalt, and nickel-cobalt. It is preferable to be configured.

  The bonding surface of the heat-resistant plating film with the organic dielectric is preferably surface-treated with a coupling agent. The coupling agent is preferably composed of at least one olefin-based silane coupling agent.

  The copper foil preferably has a roughened surface in the range of 0.3 to 3.5 μm. In this case, the copper foil is hardly peeled off, but an increase in transmission loss in the high frequency region can be suppressed. In addition, the characteristic impedance can be easily stabilized, and the structure of the copper foil can be made minute, and the electronic component member can be easily downsized or highly integrated.

  An electronic component according to a second aspect of the present invention is characterized in that a layer comprising a copper foil, a heat-resistant plating film, and an organic dielectric according to the first aspect is laminated. The electronic component of the present invention may be an electronic component for a high-frequency signal processing circuit.

  According to this invention, high adhesive force can be maintained between the copper foil and the organic dielectric.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of an electronic component member according to an embodiment of the present invention. As shown in the figure, this electronic component member is composed of a copper foil 1, a heat-resistant plating film 2, and an insulating layer (adhesive layer) 3.

  The copper foil 1 is comprised from the electrolytic copper foil or the rolled copper foil. The thickness of the copper foil 1 is arbitrary and may generally be about 3 to 70 μm, and may be properly used within this range according to required characteristics (for example, current capacity). For example, if it is desired to create a fine pattern by etching using a subtractive method or the like, good results can be obtained if the thickness of the copper foil 1 is about 3 μm to 12 μm. Moreover, what is necessary is just to let the thickness of the copper foil 1 be about 18-70 micrometers when flowing a large current or reducing the direct current | flow resistance value of a line as much as possible.

  Moreover, it is preferable that the copper foil 1 is a low profile copper foil which suppressed the roughness of the M surface. The low profile copper foil is preferably formed such that the roughness (roughening amount) of the M surface is 0.3 to 3.5 μm. This is because it is extremely difficult to form a M surface with a roughening amount of less than 0.3 μm on the copper foil, and when it exceeds 3.5 μm, the effect of the thickness of the heat-resistant plating film is difficult to be achieved. However, the roughening amount of the M surface of the copper foil may be less than 0.3 μm as long as the M surface with a roughening amount of less than 0.3 μm can be formed on the copper foil. In addition, generally the surface roughness of the standard product of electrolytic copper foil is the range of about 4.5-8 micrometers.

  The heat-resistant plating film 2 is made of zinc, zinc-tin, zinc-nickel, zinc-cobalt, copper-zinc, copper-nickel-cobalt, or nickel-cobalt. Formed. Of these materials that can constitute the heat-resistant plating film 2, the one having the best adhesiveness is a zinc-nickel system, and it is preferable to use the zinc-nickel-based heat-resistant plating film 2.

  The thickness of the heat resistant plating film 2 is formed in the range of 0.005 to 0.8 μm. By forming within this range, high adhesive force can be maintained between the copper foil 1 and the insulating layer 3. If the thickness is less than 0.005 μm, good adhesion between the copper foil 1 and the insulating layer 3 (through the heat-resistant plating film 2) cannot be obtained, and if the thickness of the heat-resistant plating film 2 is greater than 0.8 μm, This is because chemical resistance (particularly acid resistance) is lowered.

  Here, it is preferable to perform a surface treatment by immersing the exposed surface of the heat-resistant plating film 2 in a coupling agent or spraying the coupling agent on the exposed surface of the heat-resistant plating film 2. This is because the adhesion between the copper foil 1 and the insulating layer 3 can be further improved by surface treatment with a coupling agent. Suitable coupling agents include, for example, olefin silane coupling agents such as vinyl silane, acrylic silane, and methacrylic silane.

  Examples of vinyl-based silanes include pinyltrichlorosilane, vinyltrialkoxysilane, vinyl dialkoxyalkylsilane, and more specifically, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy), and the like. There are silane, vinyldimethoxymethylsilane, vinyldiethoxymethylsilane and the like.

  Examples of the acrylic silane include γ-acryloxypropyltrimethoxysilane.

  Examples of the methacrylic silane include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, and γ-methacryloxypropyltriethoxysilane.

  Of the olefin-based silane coupling agents listed above, a vinyl-based silane is particularly preferable, and among these, vinyltrimethoxysilane and vinyltriethoxysilane are particularly preferable.

  The insulating layer 3 is an organic dielectric made of an organic material, for example, a thermosetting material, and is in close contact with the copper foil 1 through the heat resistant plating film 2. This organic material (thermosetting material) has a vinylbenzyl compound or a vinylnaphthalene compound. The vinylbenzyl compound refers to vinylbenzyl or a derivative thereof, and the vinylnaphthalene compound refers to vinylnaphthalene or a derivative thereof. For example, the insulating layer 3 is made of vinyl benzyl (or a derivative thereof) or vinyl naphthalene (or a derivative thereof). Note that vinylbenzyl (or a derivative thereof) constituting the thermosetting material constituting the insulating layer 3 is vinylbenzyl in a polar solvent in the presence of an alkali or in a water / organic solvent mixed solution in the presence of a phase transfer catalyst. It can be synthesized by reacting a halide with a polymer or monomer having a phenolic hydroxyl group.

The insulating layer 3 is formed by, for example, a method shown as (a) or (b) below.
(A) The above-mentioned thermosetting material is applied to the exposed surface of the heat-resistant plating film 2 of the copper foil 1 on which the heat-resistant plating film 2 is formed and dried.
(B) A prepreg is prepared by impregnating or applying the above-mentioned thermosetting material onto a cloth or non-woven fabric made of glass, aramid, fluororesin, quartz, and / or polyethylene, and drying. The copper foil 1 having the heat-resistant plating film 2 formed on one side or both sides of the sheet is stacked so that the heat-resistant plating film 2 is in contact with the prepreg, and is hot-pressed.

  In the electronic component member having the above-described configuration, high adhesiveness is maintained between the low profile copper foil 1 and the insulating layer 3. Therefore, peeling of the copper foil 1 hardly occurs, but an increase in transmission loss in a high frequency region exceeding 1 [GHz] can be suppressed. In addition, the electronic component member can easily stabilize the characteristic impedance, and the structure of the copper foil 1 can be made minute so that the electronic component member can be easily downsized or highly integrated. is there.

The present invention is not limited to the above.
For example, a plurality of electronic component members having the above-described configuration are stacked and bonded to each other by high-temperature pressing, and a plurality of copper foils 1 to be connected are connected via vias. May be formed in multiple layers. The individual laminated plates to be bonded may be ones in which the insulating layer is formed by any of the methods (a) or (b) described above, or may be a mixture of those formed using both methods. There is no problem.
When a plurality of electronic component members are attached to each other, they may be overlapped with a cloth or non-woven fabric made of the above-mentioned materials and hot pressed.

  Further, if the surface on which the insulating layer 3 is exposed is present on the electronic component member, a multilayer electronic component may be formed by further stacking the copper foil 1 on this surface and performing high-temperature pressing.

Moreover, the coupling agent may contain 2 or more types among the olefin type silane coupling agents mentioned above.
Further, when sufficient adhesion between the heat-resistant plating film 2 and the insulating layer 3 can be secured, the electronic component member does not necessarily have to be subjected to a surface treatment with a coupling agent.

Below, the Example of this invention is described.
<Creation of copper foil>
The surface of the rolled copper foil having a thickness of about 35 [μm] constituting the copper foil 1 was subjected to roughening treatment by performing fist-like electrodeposition by copper plating. This roughening treatment is performed in a plating solution containing 10 to 25 [gram / liter] of copper and 20 to 100 [gram / liter] of sulfuric acid in an environment at a temperature of 20 to 40 [° C.] and a current density of 30 to 70. This was carried out by passing a current of [ampere / square decimeter] for 1 to 5 [seconds].

  Next, on the roughened surface formed on the copper foil 1 by this roughening treatment, a heat-resistant plating film 2 made of a zinc-nickel system is set to a thickness in the range of 0.001 to 0.013 [μm]. It formed so that it might become. The treatment for plating the roughened surface with zinc-nickel system is performed at a temperature of 40 to 40 in a plating solution having a pH of 3 to 4 and containing 10 to 30 [gram / liter] of zinc and 1 to 10 [gram / liter] of nickel. This was carried out by flowing a current having a current density of 0.5 to 5 [ampere / square decimeter] in an environment of 50 [° C.] for 1 to 3 [seconds].

  Next, an olefinic silane coupling agent was applied to the roughened surface on which the heat-resistant plating film 2 was formed, and surface treatment was performed. Application was performed by spraying a 0.4% solution of acryloxypropyltrimethoxysilane, a 0.1% solution of γ-methacryloxypropyltrimethoxysilane, or a 0.6% solution of vinyltriethoxysilane using a spray. .

<Creation of insulating layer>
Next, the insulating layer 3 was created by applying and drying a slurry containing a thermosetting material on the roughened surface on which the heat-resistant plating film 2 was formed and the coupling agent was applied.

  In order to produce this slurry, first, 100 grams of a trade name “Shonol ARS-068” (manufactured by Showa Polymer Co., Ltd.) as a polyvinyl benzyl ether compound in a polyethylene bottle having a volume of about 500 ml, and a product The name “Tuftec H-1043” (manufactured by Asahi Kasei Co., Ltd.) (15 g) was added, toluene (35 g) was added as a solvent, and the bottle was placed on a pot stand for 8 hours. As a result, a completely uniform solution was obtained.

  The slurry was applied using a gap so that the thickness was about 50 μm. Subsequently, the drying process for 6 minutes was performed at 110 degreeC, and the copper foil with a resin whose sum total of the thickness of the copper foil 1, the heat-resistant plating film 2, and the insulating layer 3 was about 85 micrometers was obtained as a result.

<Creation of double-sided copper-clad plate for evaluation>
Next, the two copper foils with resin were stacked so that the insulating layers 3 were in contact with each other, and then used in a 160 ° C. environment using a high-temperature vacuum press (“KVHC” type, manufactured by Kitagawa Seiki Co., Ltd.). For 30 minutes, and further under an environment of 200 ° C. for 1 hour, under a pressure of 3 MPa and an atmospheric pressure of 4000 Pa (30 torr) or less, a heating vacuum press was performed. The resulting double-sided copper clad plate had a thickness of about 160 μm.

<Evaluation>
Next, the various double-sided copper-clad plates prepared by the procedure described above were evaluated by the methods shown in (1) to (3) below. The evaluation results are shown in FIG.
(1) Evaluation of peel strength A peel strength test was performed according to the procedure defined in JIS C 6481. In addition, about the fracture mode, each peeling surface of the copper foil side after a peel strength test and the insulating layer side was observed and determined with the electron microscope.
(2) Evaluation of peel strength after reflow The test was conducted three times with a reflow profile having a temperature peak of 260 ° C. (duration: 5 seconds) and a temperature of 230 ° C. or higher for a duration of 40 seconds. A peel strength test was performed.
(3) Solder DIP test In accordance with JIS C 6481, the test was conducted under the condition of immersing in a solder at 260 ° C. for 30 seconds, and then the appearance swelling and peeling were visually observed.

  As shown in FIG. 2, the conditions (conditions 4 to 9) where the thickness of the heat-resistant plating film 2 is 0.007 μm or more are compared with the conditions (conditions 1 to 3) where the thickness of the heat-resistant plating film 2 is about 0.001 μm. The peel strength is great regardless of before and after reflow. On the other hand, in conditions 1 to 3, the failure mode when the copper foil 1 is peeled is exclusively interface peeling, and the interface between the heat-resistant plating film 2 and the insulating layer 3 is mechanical compared to the interface in conditions 4 to 9. It is weak.

It is sectional drawing of the member for electronic components which concerns on embodiment of this invention. It is a figure which shows the result of evaluation of the double-sided copper clad board which concerns on the Example of this invention.

Explanation of symbols

1 Copper foil 2 Heat-resistant plating film 3 Insulating layer

Claims (7)

Copper foil,
A heat-resistant plating film having a thickness of 0.005 to 0.8 μm formed on the surface of the copper foil;
An organic dielectric formed on the surface of the heat-resistant plating film and having a vinylbenzyl compound or a vinylnaphthalene compound;
An electronic component member comprising: The heat-resistant plating film is made of one or more materials selected from zinc, zinc-tin, zinc-nickel, zinc-cobalt, copper-zinc, copper-nickel-cobalt, and nickel-cobalt. It is configured,
The member for electronic components according to claim 1, wherein The bonding surface of the heat-resistant plating film with the organic dielectric is surface-treated with a coupling agent,
The member for electronic parts according to claim 1 or 2 characterized by things. The coupling agent is composed of at least one olefin-based silane coupling agent,
The electronic component member according to claim 3. The copper foil has a roughened surface in the range of 0.3 to 3.5 μm.
The member for electronic components according to claim 1, wherein the electronic component member is a member. A layer comprising the copper foil according to any one of claims 1 to 5, a heat-resistant plating film, and an organic dielectric is laminated.
An electronic component characterized by that. Used for high frequency signal processing circuit,
The electronic component according to claim 6.

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