JPS63159443A - Laminate - Google Patents

Abstract

PURPOSE:To obtain laminate having a sufficient heat dissipation property and excellent heat resistance, dimensional stability and electrical properties, by providing a specified insulating layer on a metallic base. CONSTITUTION:A polyphenylene oxide resin composition is obtained by mixing 10-95pts.wt. polyphenylene oxide of the formula (wherein R is H or a 1-3 C hydrocarbon group) with 5-50pts.wt. crosslinkable polymer (e.g., 1,2- polybutadiene) and/or 1-50pts.wt. crosslinking monomer (e.g., styrene) and 1-500pts.wt. inorganic filler (e.g., MgO) of a particle diameter of 1-20mum and a thermal conductivity at 20 deg.C>=0.115Cal/cm.S. deg.C. A nonwoven fabric 4 is fed to a dispersion 5 containing 5-50wt% said resin composition, impregnated therewith and dried to obtain a prepreg 2 of a thickness of 0.05-0.5mm. Said prepreg 2 as an insulation layer and a metal foil 1 of a thickness of 10-70mum are laminated on a metallic base 3.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a laminate having a metal base.

[Background technology]

2. Description of the Related Art As electronic devices become smaller and thinner, there is a growing trend toward higher density mounting of components on printed circuit boards. The proportion of chip-shaped components is increasing, and the characteristics required of substrate materials are becoming more diverse. Conventionally, the substrate material is
In terms of usage, density, component mounting, and reliability, materials are broadly divided into resin materials and ceramic materials, and each material has achieved unique development while taking advantage of its characteristics. but,
Various conditions surrounding substrates in recent years are eliminating clear divisions of substrate materials, and the diversification of applications and technologies is increasing the ratio of area overlap.

Against this background, the technology to apply metals to substrate materials has also been developed.
It has received particular attention in recent years.

Originally, the basic functions of printed wiring boards consisted of three major functions: insulation, conduction, and component support, and there was no room for metal plates to be involved. However, metals have unique properties, such as workability, strength, thermal conductivity, dimensional stability, magnetism, and electromagnetic shielding properties, which are extremely difficult to improve using conventional substrate materials. It is possible to easily achieve new characteristics that previously could not be achieved.

As the density of component mounting on printed wiring boards is becoming higher, market needs are becoming more stringent than before regarding basic properties of laminates, such as heat resistance, dimensional stability, and electrical properties. Among these, one of the issues that arises during high-density packaging is the heat dissipation of the board.

In order to improve the heat dissipation of the substrate, a substrate with good heat dissipation was required, and a metal-based substrate was created. For example, as shown in FIG. 1, a metal foil 1 and a metal base (metal plate) 3 are bonded together via an insulating layer such as a prepreg 2.

However, the heat dissipation properties of a material are mainly determined by the material's thermal conductivity. Figure 3 shows the thermal conductivity of various materials.

As shown in Figure 3, in general, the thermal conductivity of a resin material that is an insulator is 1O-3 (cal/mouth・S・℃) or less, and the thermal conductivity of a metal material that is an electric conductor is 10"1 .0 (c
a l /cn-s ・℃) Therefore, when a metal base substrate is fabricated using a resin material as an insulating material, there is a drawback that sufficient heat dissipation cannot be provided. .

[Purpose of the invention]

This invention was made in view of the above circumstances,
It is an object of the present invention to provide a laminate that has sufficient heat dissipation properties and also has heat resistance, dimensional stability, and electrical properties, which are the basic characteristics of a printed wiring board.

[Disclosure of the invention]

In order to achieve the above object, the inventors created a prepreg by dispersing an inorganic filler with good heat conductivity in a resin and impregnating it into a base material such as glass cloth, and using this prepreg to create an insulating material. I thought it would be good to form a layer.

However, in this case, it has been found that if the base material is a cloth-like material, the inorganic filler cannot be sufficiently enlarged in the mesh of the cloth, and therefore the thermal conductivity may not be improved as much as expected. Ta. Therefore, as a result of further research, we found that if a nonwoven fabric was used instead of a cloth-like material as the base material,
It is possible to produce a prepreg sufficiently impregnated with a resin composition containing an inorganic filler, and by forming an insulating layer using such a prepreg, a laminate with uniform quality can be produced. He discovered that this was possible and completed this invention.

Therefore, in order to achieve the above object, the present invention provides a laminate in which prepreg is used as an insulating layer on a metal base. A polyphenylene oxide resin composition containing a polymer and/or a crosslinkable monomer and an inorganic filler is impregnated, and the inorganic filler has a temperature of 0.11 at 20°C.
The gist is a laminate characterized by having a thermal conductivity of 5 [cal/cm·S·°C] or more.

The present invention will be explained in detail below.

In the laminate according to the present invention, prepreg is used as an insulating layer on a metal base. 1 of the laminate of this invention
As shown in FIG. 1, the embodiment is a so-called metal base substrate in which a metal foil 1 and a metal base (metal plate) 3 are laminated and molded with a prepreg 2 serving as an insulating layer interposed therebetween. However, the laminate according to the present invention includes a metal base substrate with a desired circuit formed by etching metal foil, that is, a printed circuit board,
Furthermore, it also includes various types of devices, such as those with electronic components mounted on printed circuit boards. In addition, the laminate of the present invention has two or more conductor layers on a metal base via an insulating layer made of prepreg (this conductor layer is a printed circuit board on which one or two or more circuits have already been formed). It may be a multilayer board on which a circuit board (or a circuit board) is formed.

An insulating layer made of prepreg is formed on the metal base. That is, a metal base, a metal foil,
Insulating layers are formed using prepreg to ensure insulation from conductor layers such as circuits.

This prepreg is impregnated with a polyphenylene oxide resin composition containing polyphenylene oxide, a crosslinkable polymer and/or a crosslinkable monomer, and an inorganic filler.

The polyphenylene oxide (also referred to as polyphenylene ether, hereinafter referred to as "PP0J") used in this invention is, for example, represented by the following general formula,
An example is poly(2,6-cymethyl-1,4-
phenylene oxide).

Such PPOs are, for example, USP 4059
It can be synthesized by the method disclosed in No. 568. For example, 2,6-xylenol is subjected to an oxidative coupling reaction with an oxygen-containing gas and methanol in the presence of a catalyst to produce poly(2,6-cymethyl-1,4
-phenylene oxide), but is not limited to this method. Here, as a catalyst, a copper (1) compound, N,N'-di-tert-butylethylenediamine,
Contains butyldimethylamine and hydrogen bromide. Based on methanol, 2 to 15% by weight of water is added to the reaction mixture system, and the total amount of methanol and water is 5 to 25% by weight.
% by weight of the polymerization solvent. Although not particularly limited, for example, weight average molecular weight (Mw)
is so, ooo, molecular weight distribution M W / M n = 4.
2 (Mn is number average molecular weight) is preferably used.

Since PPO is a resin with a low dielectric constant and low dielectric loss, it is suitable for substrates of high frequency circuits, etc., but of course it can also be used for substrates other than high frequency circuits. Also, P
PO is cheap.

Examples of crosslinkable polymers include, but are not limited to, 1,2-polybutadiene, 1,4
-Polybutadiene, styrene-butadiene copolymer, modified 1,2-polybutadiene (malein-modified, acrylic-modified, epoxy-modified), rubbers, etc.
Used alone or in combination of two or more. The polymer state may be an elastomer or a rubber, but a high molecular weight rubber state is particularly preferred since it improves film forming properties.

Although it is not a crosslinkable polymer, polystyrene may be used in order to improve film formability within a range that does not impede achievement of the object of the present invention. Note that polystyrene with a high molecular weight is desirable because it improves film-forming properties.

Examples of crosslinkable monomers include: ■Acrylates such as ester acrylates, epoxy acrylates, urethane acrylates, ether acrylate-HQ, melamine acrylates, alkyd acrylates, and silicone acrylates, ■Triaryl cyanurate, and These include polyfunctional monomers such as allyl isocyanurate, ethylene glycol dimethacrylate, divinylbenzene, and diallyl phthalate, monofunctional monomers such as vinyltoluene, ethylvinylbenzene, styrene, and paramethylstyrene, and polyfunctional epoxies. ,
They may be used alone or in combination of two or more, but are not particularly limited to these.

As the crosslinking monomer, triallyl cyanurate and/or triallyl isocyanurate are used.
It is good because it has good compatibility with PO and is preferable in terms of film formability, crosslinkability, heat resistance, and dielectric properties. Triallyl cyanurate and triallyl isocyanurate are chemically structurally isomers and have similar film-forming properties, compatibility, solubility, reactivity, etc. One or both can be used.

The crosslinkable polymer and/or crosslinkable monomer are used to improve heat resistance and the like without impairing the properties of PPO by crosslinking and curing. These may be used alone or in combination, but using them in combination is more effective in improving characteristics.

As an inorganic filler, 0.115 (ca1/c
Use a material with a thermal conductivity of at least m-s·℃]. 20
If the thermal conductivity at ℃ is less than 0.115 (cat/mouth・S・℃), the thermal conductivity of the insulating layer of the laminate will not improve much, and the inorganic Examples of the filler include silicon carbide (S i C), aluminum nitride (AjN), and beryllium oxide (also called beryllium).

), magnesium oxide (MgO), molybdenum (Mo
), each of which may be used alone or in combination of two or more, but is not limited thereto. The thermal conductivity of the inorganic filler exemplified here is 2, as shown in Figure 3.
0.115 to 0.670 [Cal/aII-3・
℃], which is almost the same as that of metals.

The shape of the inorganic light base material does not matter, but it is preferable that the size is minute.For example, in the case of particulate materials, the particle size is preferably about 50μ or less, and if it is too small, it will be difficult to handle. Because there is a risk of
1-20. More preferably, it is within the range of n.

By adjusting the type and/or amount of the inorganic filler, the thermal conductivity of the laminate can be adjusted to an arbitrary value. The upper limit of the inorganic filler in the resin composition is the point at which the laminate begins to exhibit undesirable tendencies such as becoming porous or losing strength.

A polyphenylene oxide resin composition is obtained by blending the raw materials as described above. The blending ratio is not particularly limited, but ranges from PP0IO to 95 parts by weight (more preferably,
20 to 90 parts by weight), 5 to 50 parts by weight (more preferably 5 to 45 parts by weight) of a crosslinkable polymer and/or 1 to 50 parts by weight (more preferably 5 to 20 parts by weight) of a crosslinkable monomer.
(parts by weight) and the proportion of the inorganic filler is preferably 1 to 500 parts by weight. When the proportion of the crosslinkable polymer and/or crosslinkable monomer is below the above range, adhesion may become insufficient, and when it exceeds the above range, the characteristics of PPO may not be exhibited. If the proportion of the inorganic filler is below the above range, the effect of increasing thermal conductivity may be too small, and if it exceeds the above range, the above unfavorable tendency may begin to occur. Although not particularly limited, it is preferable to use the crosslinkable polymer in a ratio of 20 parts by weight or less per 1 part by weight of the crosslinkable monomer, provided that PPO and
When used in combination with polystyrene and/or styrene-butadiene copolymer, it is preferable to use a blending weight ratio of .

In addition, an initiator is usually used in PPO resin compositions. As the initiator, the following two types can be selected depending on whether the PPO resin composition is an ultraviolet curing type or a thermosetting type, but the initiator is not limited to these. Those that generate radicals when irradiated with ultraviolet rays) include benzoin, benzyl, allyldiazonium fluorophosphate, benzyl methyl ketal, 2,2-jethoxyacetophenone, benzoyl isobutyl ether, p-tert-butyltrichloroacetophenone, Examples include benzyl (0-ethoxycarbonyl)-α-monoxime, biacetyl, acetophenone, benzophenone, Michler's ketone, tetramethylthiuram sulfide, and azobisisobutyronitrile. Examples of thermosetting initiators (that is, those that generate radicals by heat) include dicumyl peroxide, tert-butylcumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2. ,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5
-di(tert-butylperoxy)hexane, α,
α′-bis(tert-butylperoxy-m-isopropyl)benzene (1,4(or 113)-bis(t
ert-butylperoxyisopropyl)benzene], 1-hydroxycyclohexylphenyledone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-(4- isopropylphenyl)-2-hydroxy-2-methylpropane-1
-one, 2-chlorothioxanthone, methylbenzoylforme), 4,4-bisdimethylaminobenzophenone (Michler's ketone), benzoin methyl ether,
Examples include methyl-0-benzoylbenzoate, α-aziroxime ester, and Nippon Oil's bistamyl. Each of the initiators may be used alone or in combination of two or more.

A UV initiator and a thermal initiator may be used in combination.

The blending ratio of the initiator is 0.1 to the above blending ratio.
It is preferable to adjust the amount to 5 parts by weight (more preferably 0.1 to 3 parts by weight). If the proportion of initiator is below the above range,
Curing of the PPO resin composition may be insufficient,
Exceeding the above range may adversely affect the physical properties after curing.

The raw materials according to the above formulation are usually dissolved and dispersed in a solvent (inorganic fillers usually do not dissolve) and mixed (solution mixing). In this case, 5 to 5 of the PPO resin composition
A 50% by weight solution is preferred. Examples of the solvent include halogenated hydrocarbons such as trichloroethylene, trichloroethane, chloroform, methylene chloride, and chlorobenzene, aromatic hydrocarbons such as benzene, toluene, and xylene, acetone, and carbon tetrachloride. Trichlorethylene is particularly preferred; Each of them can be used alone or in combination of two or more, but is not limited thereto. Note that the mixing may be performed by other methods.

A prepreg is produced by impregnating a base material with the dispersion solution of the PPO resin composition prepared in this way and drying it.

The prepreg may be produced by any method, but generally, it can be produced by the following method.

That is, the PPO resin composition or its raw material is completely dissolved in the above-mentioned solvent at a ratio of, for example, 5 to 50% by weight (inorganic fillers usually do not dissolve), and the base material is immersed (dipped) in this solution. 7) to impregnate and adhere these PPO-based resin compositions to the base material. in this case,
The solvent may be simply removed by drying, or
It may be semi-cured to B stage. The resin content of the prepreg formed in this way is not particularly limited, but is preferably 30 to 50% by weight.

If the prepreg is produced as described above, there is no need to melt the resin, so it can be done more easily at a relatively low temperature.

A nonwoven fabric is used as the base material. Therefore, when impregnating the PPO-based resin composition, the inorganic filler sufficiently penetrates into the base material, and the inconvenience that occurs when impregnating a cloth-like object does not occur. There are no particular limitations on the material of the nonwoven fabric, but there are glass fibers, aramid fibers, polyester fibers, and mixtures of two or more of these, and materials using other synthetic fibers, natural fibers, etc. Each may be used alone or in combination of two or more. Furthermore, in the present invention, papers such as kraft paper and linter paper are also included in the nonwoven fabric. As the nonwoven fabric, a glass nonwoven fabric is preferable from the viewpoint of physical properties when used as a metal base substrate.

The prepreg may be produced by any method such as a batch method or a continuous method.

For example, the continuous method is carried out as follows,
It is not limited to this. As shown in FIG. 2, the base material 4 is continuously supplied to a dispersion solution 5 of the PPO resin composition, and the base material 4 is impregnated with the PPO resin composition and adhered thereto. This base material 4 is further continuously fed and subjected to drying A (semi-curing if necessary) to obtain a prepreg 2, which is wound onto a roll or the like.

In addition, in order to improve the adhesion at the interface between the resin component, the inorganic filler, and the nonwoven fabric, a coupling agent may be used according to a conventional method.

Copper foil, aluminum foil, etc. are used as the metal foil.
As the metal base, a metal plate such as an aluminum plate or an iron plate is used. Although not particularly limited, the thickness of the metal foil is 10 to 70 Irm (more preferably 15 to 50 Irm).
The appropriate thickness of the metal base is about 0.1 to 10 mm (more preferably 0.2 to 5 mm).

The thickness of the insulating layer is not particularly limited as long as it does not interfere with electrical insulation. For example, the thickness is about 0.05 to 0.5 fl. The insulating layer may be formed using one prepreg or two or more prepregs.

A laminate is produced, for example, in the following manner using the prepreg and metal base as described above and, if necessary, the metal foil as described above, but the method is not limited thereto. or
A predetermined number of sheets of the prepreg produced as described above are assembled to have a predetermined design thickness, and this is laminated by being sandwiched between metal foil and a metal base, and the resin is melted by heating and pressing, etc. , the metal foil, prepreg and metal base are adhered to each other to obtain a laminate. Strong adhesion can be obtained by this fusion alone, but even stronger adhesion can be obtained if a crosslinking reaction using a radical initiator is performed by heating at this time. The crosslinking reaction may be carried out by ultraviolet irradiation or the like.

When thermal crosslinking and photocrosslinking are not performed, crosslinking by radiation irradiation may be performed.Furthermore, crosslinking by radiation irradiation may be performed after thermal crosslinking and photocrosslinking. This makes it possible to create adhesives with excellent heat resistance between metal bases, prepregs, and metal foils.

For adhesion between prepregs, between prepregs and metal bases, and between prepregs and metal foils, the heat fusion properties of prepregs can be utilized, so the lamination compaction temperature is above the glass transition point of the prepregs, and is approximately in the range of 160 to 300℃. is preferred. In a solidified product of a PPO resin composition, the resin flows slightly before curing, so it exhibits good fusion properties to metals.

However, an adhesive may be used in combination.

When making a laminate, the conductor layer is, for example, a metal layer, and the metal layer is, for example, a metal foil such as copper foil or aluminum foil.

The metal foil has a smooth adhesive surface and good conductivity.
This is preferable in terms of improving dielectric properties. Alternatively, a metal layer may be formed by vapor deposition, or a desired conductor (circuit, electrode, etc.) may be formed by a subtractive method, an additive method (full additive method, semi-additive method), etc.
It may be formed as, and there is no particular limitation.

Pressing is performed to bond the prepregs to each other, to the metal base, to the prepreg and the metal foil, and to adjust the thickness of the laminate, so the pressing conditions are selected as necessary.

Furthermore, when crosslinking the PPO resin composition used in the present invention by heating, the crosslinking reaction depends on the reaction temperature of the initiator used, so the heating temperature should be selected depending on the type of initiator. The heating time may also be selected depending on the type of initiator, etc. For example, temperature 150~300℃, time 10~
The duration is approximately 60 minutes. The pressure for clamping is, for example,
It is preferable to set it to about 50 kg/d. A predetermined number of sheets of the prepreg may be heated and laminated in advance, and the prepregs may be sandwiched between a metal base and a metal foil, stacked one on top of the other, and heated and pressed again.

When a radiation crosslinkable polymer is used as the crosslinkable polymer and a radiation crosslinkable monomer is used as the crosslinkable monomer, radiation crosslinking is preferably performed after bonding the prepreg to the metal foil and metal base.

Since the thus obtained laminate uses PPO, a crosslinkable polymer and/or a crosslinkable monomer,
Excellent heat resistance and electrical properties. Furthermore, since a nonwoven fabric is used as the base material, the prepreg sufficiently contains an inorganic filler with good thermal conductivity, and the obtained laminate has excellent heat dissipation properties. Moreover, since the PPO resin composition contains an inorganic filler, in addition to these properties, dimensional stability is further improved and solvent resistance is also improved. The manufacturing operation is also simple as described above.

Next, Examples and Comparative Examples will be described, but the present invention is not limited to the Examples.

(Example 1) 25 parts by weight of PPO alone, 5 parts by weight of styrene-butadiene copolymer (SBS, Asaprene manufactured by Asahi Kasei Corporation) as a crosslinkable polymer, and 1,2-polybutadiene (1,2-
3 parts by weight of PBu (manufactured by Nippon Soda ■), 3 parts by weight of triallylisocyanuride (TAIC1 manufactured by Nippon Kasei ■) as a crosslinking monomer, 2.5-dimethyl-2, as a reaction initiator
5-di(tert-butylperoxy)hexyne-3
Dissolve 0.5 parts by weight of Perhexin 25B (manufactured by NOF ■) in trichlorethylene to make a solution with a concentration of approximately 20% by weight, and add magnesium oxide (as an inorganic filler) to this solution.
180 parts by weight of MgO) was added, and the mixture was sufficiently stirred in a reactor equipped with a defoaming device until the mixture became homogeneous. After this, defoaming is performed,
A PPO resin composition which became a solution blend was obtained.

A glass nonwoven fabric (manufactured by Asahi Schniebel ■) was impregnated with this PPO-based resin composition. It was air-dried as it was, further dried in a dryer at 50°C for 10 minutes, and then further dried at 120°C for 30 minutes. A 18-thick copper foil is placed on one side of the prepreg thus obtained, and a 1.01-thick copper foil is placed on the other side.
1 aluminum plates were stacked on top of each other and heated at 240°C.
A laminate was obtained by pressing at 50 kg/ad for 30 minutes.

(Examples 2 to 7) Laminated plates were produced in the same manner as in Example 1, except that the raw materials having the composition shown in Table 1 were used.

(Comparative Examples 1 to 7) Using raw materials with the composition shown in Table 1,
A prepreg was produced using glass cloth (manufactured by Asahi Schniebel ■) as a base material. A laminate was produced in the same manner as in Example 1, except that this prepreg was used instead of the prepreg used in Example 1.

(Comparative Example 8) A prepreg was produced by impregnating glass cloth with an epoxy resin. A laminate was produced in the same manner as in Example 1, except that this prepreg was used instead of the prepreg used in Example 1.

Table 1 shows the results of examining the physical properties of the laminates obtained in Examples 1 to 7 and Comparative Examples 1 to 8. However, regarding warpage, after removing the entire copper foil on one side of a laminate formed to a size of 3001m x 300wm by etching, the laminate is placed on a flat surface with the removed side facing upward, and between each corner and the flat surface. We decided to measure the average distance.

As shown in Table 1, the thermal conductivity of each of the laminates of Examples 1 to 7 is higher than that of the laminate of Comparative Example 8 impregnated with only resin, indicating that the laminates have good heat dissipation properties. Moreover, when comparing the laminates of Examples 1 to 7 and the laminates of Comparative Examples 1 to 7,
It can be seen that when the same amount of the same inorganic filler is used, the thermal conductivity of the laminate is higher and the heat dissipation property is better when a nonwoven fabric is used than when a cloth-like base material is used. Moreover, the laminates of Examples 1 to 7 have better solder heat resistance and dielectric loss tangent than the laminate of Comparative Example 8. The warpage is from Example 1 to
The laminates of No. 7 and Comparative Examples 1 to 8 are approximately equal to or better than those of Comparative Examples 1 to 8, and are excellent.

The insulation resistance is also approximately the same as that of the laminates of Examples 1 to 7 and Comparative Examples 1 to 8.

〔Effect of the invention〕

As seen above, the laminate of this invention has PP01
a crosslinkable polymer and/or a crosslinkable monomer, and
A prepreg impregnated with a PPO resin composition containing an inorganic filler is used as an insulating layer, a nonwoven fabric is used as a base material, and the inorganic filler is
．． Since it has a thermal conductivity of 115 (ca1/3·S·°C) or higher, it has sufficient heat dissipation properties and is also excellent in heat resistance, electrical properties, and dimensional stability.

[Brief explanation of the drawing]

Figure 1 is an exploded cross-sectional view of an example of the layer structure of a metal base substrate, Figure 2 is a schematic diagram of an example of prepreg production, and Figure 3 is a graph of the thermal conductivity of various materials. be. 1... Metal foil 2... Prepreg 3... Metal base (metal plate) Agent Patent attorney Takehiko Matsumoto Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) In a laminate in which a prepreg is used as an insulating layer on a metal base, the prepreg uses a nonwoven fabric as a base material, and contains polyphenylene oxide, a crosslinkable polymer and/or a crosslinkable monomer, and an inorganic It is impregnated with a polyphenylene oxide resin composition containing a filler, and the inorganic filler has a temperature of 0.
A laminate having a thermal conductivity of 115 [cal/cm・s・℃] or more. (2) The polyphenylene oxide resin composition contains 10 to 95 parts by weight of polyphenylene oxide, 5 to 50 parts by weight of a crosslinkable polymer, and/or 1 to 10 parts by weight of a crosslinkable monomer.
50 parts by weight and an inorganic filler in a proportion of 1 to 500 parts by weight, respectively.