JP7325038B2 - METHOD FOR MANUFACTURING METAL-CLAID LAMINATES - Google Patents

Description

TECHNICAL FIELD The present disclosure generally relates to a method for manufacturing a metal-clad laminate, and more particularly to a method for manufacturing a metal-clad laminate in which a resin sheet and a metal foil are laminated and heated.

Patent Literature 1 discloses a method for producing a metal-clad laminate. In this method, a metal-clad laminate is produced by laminating a metal foil on a prepreg to form a laminate, and molding the laminate under heat and pressure. The heating and pressurizing conditions are a temperature of 170 to 210° C., a pressure of 1.5 to 4.0 MPa, and a time of 60 to 150 minutes.

WO2015/064064

A metal-clad laminate is processed into a printed wiring board by, for example, a build-up method and a plated through-hole method. The printed wiring board thus obtained can be used not only as a mother board but also as a package substrate. A semiconductor chip such as a bare chip is mounted on the package substrate. The semiconductor chip is connected to the package substrate by reflow soldering. Reflow soldering heats the solder alloy until it melts, which exposes the package substrate to high temperatures. The high temperature may warp the package substrate and reduce the connection reliability of the semiconductor chip.

An object of the present disclosure is to provide a method for manufacturing a metal-clad laminate that can reduce warping at high temperatures.

A method for manufacturing a metal-clad laminate according to an aspect of the present disclosure includes a step of stacking a resin sheet and a metal foil to form a laminate, and a treatment step of heating the laminate to a temperature within the range of 3000° C.·min or more. The resin sheet contains a modified polyphenylene ether compound (A) having terminal groups having unsaturated double bonds and a cross-linking agent (B) having carbon-carbon double bonds.

(In formula (1), Th (° C. min) indicates the thermal history. Tmax (° C.) indicates the maximum temperature and satisfies 240≦Tmax≦350. Ts (° C.) indicates the temperature at which temperature rise starts. (°C/sec) indicates the rate of temperature rise, Ht (min) indicates the maximum temperature retention time, and satisfies 1.5 ≤ Ht ≤ 6.0.)

According to the present disclosure, warping at high temperatures can be reduced.

FIG. 1 is a schematic front view schematically showing a double belt press device. FIG. 2 is a graph schematically showing the curing reaction process of the resin composition.

(1) Overview In this embodiment, a metal-clad laminate 1 is manufactured. The metal-clad laminate 1 is a main material for manufacturing printed wiring boards.

The metal-clad laminate 1 includes an insulating layer 5 and a metal foil 3 (see FIG. 1). The insulating layer 5 is a layer having electrical insulation. The insulating layer 5 is a layer formed by curing the resin sheet 2 . The metal foil 3 is adhered to both sides or one side of the insulating layer 5 .

When the metal foil 3 is adhered to both surfaces of the insulating layer 5, the metal-clad laminate 1 is also called a double-sided metal-clad laminate. When the metal foil 3 is adhered to one side of the insulating layer 5, the metal-clad laminate 1 is also called a single-sided metal-clad laminate. Although the method for manufacturing a double-sided metal-clad laminate will be described below, this method can also be applied to a method for manufacturing a single-sided metal-clad laminate.

The method for manufacturing the metal-clad laminate 1 according to the present embodiment includes a step of stacking a resin sheet 2 and a metal foil 3 to form a laminate 4, and a treatment step of heating the laminate 4. include. The resin sheet 2 contains a modified polyphenylene ether compound (A) having terminal groups having unsaturated double bonds and a cross-linking agent (B) having carbon-carbon double bonds. The heating is performed so that the heat history Th represented by the following formula (1) is within the range of 500° C.·min or more and 3000° C.·min or less.

(In formula (1), Th (° C. min) indicates the thermal history. Tmax (° C.) indicates the maximum temperature and satisfies 240≦Tmax≦350. Ts (° C.) indicates the temperature at which temperature rise starts. (°C/sec) indicates the rate of temperature rise, Ht (min) indicates the maximum temperature retention time, and satisfies 1.5 ≤ Ht ≤ 6.0.)
In this embodiment, the metal-clad laminate 1 is manufactured in a short period of time at a high temperature instead of a long period of time at a low temperature. Thereby, the glass transition temperature (Tg) of the insulating layer 5 of the metal-clad laminate 1 can be lowered. Therefore, the modulus of elasticity of the metal-clad laminate 1 at high temperatures can be reduced. Therefore, warping at high temperatures can be reduced.

(2) Details <Material>
Materials for the metal-clad laminate 1 according to the present embodiment include a resin sheet 2 and a metal foil 3 .

≪Resin sheet≫
The resin sheet 2 is a long resin sheet that can be wound up. The resin sheet 2 includes a resin composition (hereinafter also referred to as composition (X)) and a base material. The composition (X) is impregnated into the substrate.

The composition (X) includes a modified polyphenylene ether compound (A) (hereinafter also referred to as compound (A)) having a group having an unsaturated double bond at its end, and a cross-linking agent having a carbon-carbon double bond (B ) (hereinafter also referred to as a cross-linking agent (B)). That is, the resin sheet 2 contains the compound (A) and the cross-linking agent (B).

[Compound (A)]
The compound (A) tends to achieve a low dielectric constant and a low dielectric loss tangent of the cured product of the composition (X). Compound (A) is a polyphenylene ether terminally modified with a group having an unsaturated double bond (carbon-carbon unsaturated double bond). That is, compound (A) has, for example, a polyphenylene ether chain and a group having an unsaturated double bond bonded to the end of the polyphenylene ether chain.

Examples of the group having an unsaturated double bond include substituents represented by the following formula (2).

In formula (2), n is a number from 0 to 10. Z is an arylene group. R ¹ to R ³ are each independently a hydrogen atom or an alkyl group. In formula (2), when n is 0, Z is directly attached to the end of the polyphenylene ether chain.

The arylene group is, for example, a monocyclic aromatic group such as a phenylene group, or a polycyclic aromatic group such as a naphthylene group. At least one hydrogen atom bonded to an aromatic ring in the arylene group may be substituted with a functional group such as an alkenyl group, alkynyl group, formyl group, alkylcarbonyl group, alkenylcarbonyl group, or alkynylcarbonyl group. The arylene group is not limited to those mentioned above.

The alkyl group is, for example, preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specifically, the alkyl group is, for example, a methyl group, an ethyl group, a propyl group, a hexyl group, a decyl group, or the like. The alkyl group is not limited to those mentioned above.

Groups having an unsaturated double bond include vinylbenzyl groups (ethenylbenzyl groups) such as p-ethenylbenzyl groups and m-ethenylbenzyl groups, vinylphenyl groups, acrylate groups, methacrylate groups, and the like. A group having an unsaturated double bond preferably has a vinylbenzyl group, a vinylphenyl group, or a methacrylate group. If the group having an unsaturated double bond has an allyl group, the reactivity of compound (A) tends to be low. Also, if the group having an unsaturated double bond has an acrylate group, the reactivity of compound (A) tends to be too high.

A preferred specific example of the group having an unsaturated double bond is a functional group containing a vinylbenzyl group. Specifically, the group having an unsaturated double bond is, for example, a substituent represented by the following formula (3).

In formula (3), R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ² is a single bond or an alkylene group having 1 to 10 carbon atoms. R ² is preferably an alkylene group having 1 to 10 carbon atoms.

A group having an unsaturated double bond may be a (meth)acrylate group. A (meth)acrylate group is represented, for example, by the following formula (4).

In formula (4), ^R4 is a hydrogen atom or an alkyl group. The alkyl group is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specifically, for example, the alkyl group is a methyl group, an ethyl group, a propyl group, a hexyl group, a decyl group, or the like. Alkyl groups are not limited to those listed above.

As described above, compound (A) has a polyphenylene ether chain in its molecule. A polyphenylene ether chain has, for example, a repeating unit represented by the following formula (5).

In formula (5), m is a number from 1 to 50. Each of R ⁵ to R ⁸ is independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Each of R ⁵ to R ⁸ is preferably a hydrogen atom or an alkyl group. The alkyl group is, for example, preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specifically, the alkyl group is, for example, a methyl group, an ethyl group, a propyl group, a hexyl group, a decyl group, or the like. The alkenyl group is, for example, preferably an alkenyl group having 2 to 18 carbon atoms, more preferably an alkenyl group having 2 to 10 carbon atoms. Specifically, the alkenyl group is, for example, a vinyl group, an allyl group, a 3-butenyl group, or the like. The alkynyl group is, for example, preferably an alkynyl group having 2 to 18 carbon atoms, more preferably an alkynyl group having 2 to 10 carbon atoms. Specifically, the alkynyl group is, for example, an ethynyl group, a prop-2-yn-1-yl group (propargyl group), or the like. The alkylcarbonyl group may be any carbonyl group substituted with an alkyl group. For example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferable, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferable. Specifically, the alkylcarbonyl group is, for example, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, a cyclohexylcarbonyl group, or the like. The alkenylcarbonyl group may be a carbonyl group substituted with an alkenyl group. For example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferable, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferable. Specifically, the alkenylcarbonyl group is, for example, an acryloyl group, a methacryloyl group, a crotonoyl group, or the like. The alkynylcarbonyl group may be a carbonyl group substituted with an alkynyl group. For example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferable, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferable. Specifically, an alkynylcarbonyl group is, for example, a propioloyl group and the like. Alkyl groups, alkenyl groups, alkynyl groups, formyl groups, alkylcarbonyl groups, alkenylcarbonyl groups and alkynylcarbonyl groups are not limited to those mentioned above.

The number average molecular weight of compound (A) is preferably 1,000 to 5,000, more preferably 1,000 to 4,000, even more preferably 1,000 to 3,000. The number average molecular weight is a value obtained by converting the measurement results obtained by gel permeation chromatography (GPC) into polystyrene. When compound (A) has a repeating unit represented by formula (5) in the molecule, m in formula (5) is such that the number average molecular weight of compound (A) is within the above preferred range. It is preferable that the numerical value is such that Specifically, m is preferably 1 or more and 50 or less. When the number average molecular weight of the compound (A) is within such a range, the compound (A) imparts excellent dielectric properties to the cured product of the composition (X) due to the polyphenylene ether chain, and furthermore, the cured product Heat resistance and moldability can be improved. The reason for this is as follows. When the number average molecular weight of unmodified polyphenylene ether is about 1000 or more and 5000 or less, the polyphenylene ether has a relatively low molecular weight and tends to lower the heat resistance of the cured product. On the other hand, since compound (A) has an unsaturated double bond at the terminal, it is thought that the heat resistance of the cured product can be enhanced. Further, when the number average molecular weight of compound (A) is 5,000 or less, it is believed that the moldability of composition (X) is less likely to be impaired. Therefore, it is considered that compound (A) can improve not only the heat resistance of the cured product, but also the moldability of composition (X). When the number average molecular weight of compound (A) is 1000 or less, the glass transition temperature of the cured product is less likely to decrease, and thus the cured product tends to have good heat resistance. Furthermore, since the polyphenylene ether chain in the compound (A) is less likely to be shortened, the excellent dielectric properties of the cured product due to the polyphenylene ether chain are likely to be maintained. Moreover, when the number average molecular weight is 5000 or less, the compound (A) is easily dissolved in a solvent, and the storage stability of the composition (X) is less likely to deteriorate. In addition, the compound (A) does not easily increase the viscosity of the composition (X), so that the composition (X) is likely to have good moldability.

Compound (A) preferably does not contain high molecular weight components having a molecular weight of 13,000 or more, or the content of high molecular weight components having a molecular weight of 13,000 or more in compound (A) is 5% by mass or less. That is, the content of high molecular weight components having a molecular weight of 13000 or more in compound (A) is preferably 0% by mass or more and 5% by mass or less. In this case, the cured product can have particularly excellent dielectric properties, and the composition (X) can have particularly excellent reactivity and storage stability, and is particularly excellent in fluidity. More preferably, the content of the high molecular weight component is 3% by mass or less. The content of the high-molecular-weight component can be calculated based on the measured molecular weight distribution, for example, by measuring the molecular weight distribution using gel permeation chromatography (GPC).

The average number of groups having an unsaturated double bond (number of terminal functional groups) per molecule of compound (A) is preferably 1 or more, more preferably 1.5 or more, and 1 .7 or more is more preferable, and 1.8 or more is particularly preferable. In these cases, it is easy to ensure the heat resistance of the cured product of the composition (X). The average number of groups having unsaturated double bonds is preferably 5 or less, more preferably 3 or less, more preferably 2.7 or less, particularly 2.5 or less. preferable. In these cases, it is possible to prevent the reactivity and viscosity of compound (A) from becoming excessively high. It is possible to make it difficult to cause troubles such as In addition, it is possible to make it difficult for unreacted unsaturated double bonds to remain after the composition (X) is cured. The terminal functional group number of the compound (A) is the average value of the substituents per molecule in 1 mol of the compound (A). The number of terminal functional groups is, for example, when polyphenylene ether is modified to synthesize compound (A), the number of hydroxyl groups in compound (A) is measured, and the number of hydroxyl groups in compound (A) is the number of polyphenylenes before modification. It is obtained by calculating the amount of decrease from the number of hydroxyl groups of the ether. The decrease from the number of hydroxyl groups of the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in compound (A) is determined by measuring the UV absorbance of a mixed solution obtained by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of compound (A). can ask.

The intrinsic viscosity of compound (A) is preferably 0.03 dl/g or more and 0.12 dl/g or less, more preferably 0.04 dl/g or more and 0.11 dl/g or less, and 0.06 dl/g or more. It is more preferably 0.095 dl/g or less. In this case, the dielectric constant and dielectric loss tangent of the cured product of composition (X) are more likely to be lowered. By imparting sufficient fluidity to the composition (X), the moldability of the composition (X) can be improved.

The intrinsic viscosity is the intrinsic viscosity measured in methylene chloride at 25° C. More specifically, for example, compound (A) is dissolved in methylene chloride at a concentration of 0.18 g/45 ml. It is the viscosity of the solution at 25°C. This viscosity is measured with a viscometer such as Schott's AVS500 Visco System.

There are no particular restrictions on the method for synthesizing compound (A). For example, compound (A) can be synthesized by reacting polyphenylene ether with a compound in which a group having an unsaturated double bond and a halogen atom are bonded. More specifically, polyphenylene ether and a compound in which a group having an unsaturated double bond and a halogen atom are bonded are dissolved in a solvent and stirred. Thereby, the polyphenylene ether reacts with the compound in which the group having an unsaturated double bond and the halogen atom are bonded to obtain the compound (A).

[Crosslinking agent (B)]
The cross-linking agent (B) forms a cross-linked structure by reacting with the compound (A).

Crosslinkers (B) are for example from divinylbenzene, polybutadiene, alkyl (meth)acrylates, tricyclodecanol (meth)acrylate, fluorene (meth)acrylate, isocyanurate (meth)acrylate and trimethylolpropane (meth)acrylate. containing at least one component selected from the group consisting of

Among these, the cross-linking agent (B) preferably contains polybutadiene from the viewpoint of lowering the dielectric constant. The percentage of the cross-linking agent (B) is preferably 5% by mass or more and 70% by mass or less, and is 10% by mass or more and 60% by mass or less with respect to the total amount of the compound (A) and the cross-linking agent (B). is more preferable, and more preferably 10% by mass or more and 50% by mass or less. In these cases, the moldability of the composition (X) can be particularly improved and the heat resistance of the cured product can be particularly improved while the cured product maintains the excellent dielectric properties of the compound (A).

[Phosphorus compound]
Composition (X) may further contain a phosphorus compound (hereinafter also referred to as phosphorus compound (C)). That is, the resin sheet 2 may further contain a phosphorus compound (C). Thereby, flame retardance can be imparted to the metal-clad laminate 1 .

Examples of the phosphorus compound (C) include, but are not particularly limited to, phosphates and phosphinates. In particular, phosphate esters also have the effect of plasticizing resins. Therefore, if the resin sheet 2 contains a phosphate ester, the glass transition temperature (Tg) is lowered, and the resin sheet 2 softens at a lower temperature than when the phosphate ester is not contained, thereby facilitating plastic working. . On the other hand, phosphinates are also effective in suppressing coloration such as yellowing.

When the resin sheet 2 further contains the phosphorus compound (C), the content of the phosphorus compound (C) is preferably less than 40 parts by weight with respect to a total of 100 parts by weight of the compound (A) and the cross-linking agent (B). , more preferably 35 parts by mass or less, and still more preferably 30 parts by mass or less. This makes it easier to lower the dielectric constant of the metal-clad laminate 1 . The low-permittivity metal-clad laminate 1 is useful for reducing transmission loss of high-frequency signals.

When the resin sheet 2 further contains the phosphorus compound (C), the content of phosphorus atoms is preferably 6 parts by mass or less, more preferably 100 parts by mass in total of the compound (A) and the cross-linking agent (B). is 4.5 parts by mass or less, more preferably 4 parts by mass or less. This makes it easier to lower the dielectric constant of the metal-clad laminate 1 . The low-permittivity metal-clad laminate 1 is useful for reducing transmission loss of high-frequency signals.

[Inorganic filler]
Composition (X) may further contain an inorganic filler (hereinafter also referred to as inorganic filler (D)). That is, the resin sheet 2 may further contain an inorganic filler (D). This makes it possible to effectively improve mechanical properties, impart functionality, control workability, and the like.

Examples of the inorganic filler (D) include, but are not limited to, silica. Silica is effective in reducing the coefficient of linear expansion, preventing curing shrinkage, and improving thermal conductivity. Silica includes fused silica and the like.

The shape of the inorganic filler (D) is not particularly limited, but is preferably spherical, for example.

The average particle size of the inorganic filler (D) is not particularly limited, but is, for example, within the range of 0.2 μm or more and 15 μm or less.

When the resin sheet 2 contains the inorganic filler (D), the content of the inorganic filler (D) is preferably 20 parts by mass with respect to a total of 100 parts by mass of the compound (A) and the cross-linking agent (B). It is within the range of 250 mass parts or less.

〔solvent〕
Composition (X) may further contain a solvent. This makes it easier to impregnate the substrate with the composition (X) as a varnish.

〔Base material〕
Examples of the substrate include, but are not limited to, glass cloth. The thickness of the substrate is not particularly limited, but is, for example, within the range of 8 μm or more and 200 μm or less.

The resin sheet 2 is obtained by impregnating a base material with the composition (X). When the composition (X) contains a solvent, the substrate may be impregnated with the composition (X) and then dried to remove the solvent.

≪Metal foil≫
The metal foil 3 is not particularly limited, but for example, a copper foil can be used. The thickness of the metal foil 3 is not particularly limited, but is, for example, within the range of 2 μm or more and 105 μm or less.

<Manufacturing method>
The method for manufacturing the metal-clad laminate 1 according to the present embodiment includes a step of stacking a resin sheet 2 and a metal foil 3 to form a laminate 4, and a treatment step of heating the laminate 4. include. Preferably, in the treatment step, the laminate 4 is heated and pressurized. Apparatus suitable for manufacturing the metal-clad laminate 1 and heating and pressurizing conditions will be described below.

≪Equipment≫
A double belt press device 100 is shown in FIG. The double belt press device 100 includes a first conveyor 110, a second conveyor 120, and a heating and pressurizing device . The double belt press device 100 may further include a cooling device 140 .

The first conveyor 110 has a first belt 151 , a first entrance roll 161 and a first exit roll 171 . The first belt 151 is an endless belt. An endless belt is a belt that is joined endlessly. The first belt 151 is a steel belt, such as a stainless steel belt. The first belt 151 is stretched between the first entrance roll 161 and the first exit roll 171 . The first entrance roll 161 and the first exit roll 171 are rotatably supported and arranged in parallel. The speed of the first belt 151 is adjustable.

The second conveyor 120 is arranged facing the first conveyor 110 . The second conveyor 120 has a second belt 152 , a second entry roll 162 and a second exit roll 172 . The second belt 152 is an endless belt. The second belt 152 is a steel belt, such as a stainless steel belt. The second belt 152 is stretched between the second entrance roll 162 and the second exit roll 172 . The second belt 152 faces the first belt 151 . A second entry roll 162 and a second exit roll 172 are rotatably supported and arranged in parallel. The speed of the second belt 152 is adjustable. The second belt 152 can also be synchronized with the first belt 151 .

The first inlet roll 161 and the second inlet roll 162 are arranged in parallel. Hereinafter, the first entrance roll 161 and the second entrance roll 162 may be collectively referred to as the entrance roll 160. The first exit roll 171 and the second exit roll 172 are also arranged in parallel. Hereinafter, the first exit roll 171 and the second exit roll 172 may be collectively referred to as the exit roll 170 .

The heating and pressurizing device 130 is arranged between the entrance roll 160 and the exit roll 170 . Known means can be applied to the heating means and pressurizing means of the heating and pressurizing device 130 . The heating and pressurizing device 130 can adjust the heating temperature, press pressure, temperature increase rate, and heating time.

The cooling device 140 is arranged between the heating and pressurizing device 130 and the exit roll 170 . A known means can be applied to the cooling means of the cooling device 140 . The cooling device 140 may further have pressurizing means. A known means can be applied to the pressurizing means of the cooling device 140 . The cooling device 140 can adjust the cooling temperature, cooling rate, and cooling time. If the cooling device 140 further comprises pressurizing means, the press pressure can also be adjusted.

As described above, in this embodiment, the double belt press device 100 is used to perform heating by a roll-to-roll method. More specifically, heating and pressurization are performed by a roll-to-roll method. Therefore, productivity can be improved as compared with a batch press method using a batch press device.

≪Heating and pressurizing conditions≫
In this embodiment, a double-sided metal-clad laminate is manufactured as the metal-clad laminate 1 using the double belt press apparatus 100 shown in FIG. That is, the metal foils 3 are arranged on both sides of the resin sheet 2, these are stacked to form a laminate 4, and the laminate 4 is inserted between the first conveyor 110 and the second conveyor 120 from the inlet roll 160 side. The laminate 4 is sandwiched between the first belt 151 and the second belt 152 and conveyed from the entrance roll 160 side to the exit roll 170 side. The laminate 4 is heated and pressurized by the heating and pressurizing device 130 during transportation. As a result, the laminate 4 becomes the metal-clad laminate 1 . Specifically, the resin sheet 2 becomes the insulating layer 5 and is adhered to the metal foils 3 on both sides. After being heated and pressurized, the metal-clad laminate 1 is cooled by the cooling device 140 as necessary, and then comes out from the exit roll 170 side.

In the present embodiment, the heating is performed so that the heat history Th represented by the following formula (1) falls within the range of 500° C.·min or more and 3000° C.·min or less. By adjusting the thermal history Th in this manner, warping of the metal-clad laminate 1 at high temperatures can be reduced. A high temperature is, for example, a temperature to which the package substrate is exposed during reflow soldering. Specifically, the temperature is about 260°C.

(In formula (1), Th (° C. min) indicates the thermal history. Tmax (° C.) indicates the maximum temperature and satisfies 240≦Tmax≦350. Ts (° C.) indicates the temperature at which temperature rise starts. (°C/sec) indicates the rate of temperature rise, Ht (min) indicates the maximum temperature retention time, and satisfies 1.5 ≤ Ht ≤ 6.0.)
The temperature rise start temperature (Ts) is the temperature immediately before the laminate 4 is heated by the heating and pressurizing device 130 . The temperature rise start temperature (Ts) is not particularly limited, but is, for example, a temperature within the range of 15°C or higher and 50°C or lower.

Next, the laminate 4 is heated by the heating/pressurizing device 130 from the temperature rise start temperature (Ts) to the maximum temperature (Tmax). The rate of temperature increase (Tv) at this time is not particularly limited, but is preferably in the range of 2° C./sec or more and 8° C./sec or less. That is, it is preferable to further satisfy 2≦Tv≦8 in the above formula (1). By heating at a temperature rising rate within the above range, warpage of the metal-clad laminate 1 at high temperatures can be further reduced compared to heating at a temperature rising rate outside the above range. The maximum temperature (Tmax) is a temperature within the range of 240°C or higher and 350°C or lower.

On the other hand, the laminate 4 is pressurized by the heating and pressurizing device 130 from the temperature rise start temperature (Ts) to the maximum temperature (Tmax). The pressure (press pressure) at this time is not particularly limited, but is, for example, within the range of 0.5 MPa or more and 5 MPa or less.

After reaching the maximum temperature (Tmax), the maximum temperature (Tmax) is maintained within a range of 1.5 minutes or more and 6.0 minutes or less.

On the other hand, the pressure (press pressure) while maintaining the maximum temperature (Tmax) is preferably 0.5 MPa or more. Pressurization at a pressure within the above range can further reduce warpage at high temperatures compared to pressurization at a pressure outside the above range. Although the upper limit of the pressure while maintaining the maximum temperature (Tmax) is not particularly limited, it is, for example, 5 MPa.

<Presumed mechanism>
Next, regarding the metal-clad laminate 1 according to the present embodiment, a presumed mechanism for reducing warpage at high temperatures will be described.

FIG. 2 is a graph schematically showing the curing reaction process of the resin composition. The vertical axis indicates the melt viscosity of the resin composition, and the horizontal axis indicates the heating time of the resin composition. The resin composition contains resin A (compound (A) in the present embodiment) and resin B (crosslinking agent (B) in the present embodiment). Curve C1 is a graph showing the curing reaction process at high temperature for a short period of time. A curve C1 is a graph showing the present embodiment. Curve C2 is a graph showing the curing reaction process at low temperature for a long time. In FIG. 2, η(ab) indicates the maximum melt viscosity at which resin A and resin B can be crosslinked.

When the resin composition is heated, the higher the probability that the reactive groups of resin A and the reactive groups of resin B meet, the higher the crosslink density. The above probability is inversely proportional to the melt viscosity of the resin composition. That is, when the melt viscosity is low, the resin A and the resin B move more easily, so the above probability increases. Conversely, if the melt viscosity is high, the resin A and the resin B will be difficult to move, so the above probability will be low.

In the curing reaction process at a low temperature for a long time, as shown by the curve C2 in FIG. 2, the melt viscosity gradually decreases with heating, and when further heated, the curing reaction starts and the melt viscosity gradually increases. In such a process, the temperature rise rate is slow and the minimum melt viscosity is high. In curve C2, the time (t2) from η(ab) to η(ab) again after passing through the lowest melt viscosity increases, so the probability that resin A and resin B meet increases, and the crosslink density increases. . As a result, the glass transition temperature (Tg) of the cured product of the resin composition becomes high, and easily exceeds 210° C., for example. Therefore, the elastic modulus of the cured product at a high temperature (for example, 260° C.) tends to be high. Therefore, the metal-clad laminate 1 manufactured through a curing reaction process at a low temperature for a long time tends to warp at a high temperature.

On the other hand, in the curing reaction process at high temperature for a short time (that is, this embodiment), as shown by the curve C1 in FIG. The melt viscosity begins to rise rapidly. In such a process, the temperature rise rate is high and the minimum melt viscosity is low. In the curve C1, the time (t1) from η(ab) to η(ab) again after passing through the lowest melt viscosity is shorter than the above t2 (t1<t2). are less likely to meet, resulting in a lower crosslink density. As a result, the glass transition temperature (Tg) of the cured product of the resin composition is lowered, and tends to be 210° C. or lower, for example. Therefore, the elastic modulus of the cured product at a high temperature (for example, 260° C.) tends to be low. Therefore, the metal-clad laminate 1 produced through the curing reaction process at high temperature for a short period of time is less likely to warp at high temperatures. It is difficult to obtain such a metal-clad laminate 1 by the batch press method. The glass transition temperature (Tg) of the cured product of the resin composition is preferably 180°C or higher.

(3) Modification In the above-described embodiment, the metal-clad laminate 1 is manufactured using the double belt press machine 100. However, a double belt press machine can be used as long as it is capable of heating and pressurizing at high temperature in a short time. Not limited to 100. For example, a roll type laminator may be used.

EXAMPLES The present disclosure will be specifically described below with reference to Examples. However, the present disclosure is not limited to the examples.

[Metal clad laminate]
<Material>
≪Resin sheet≫
The resin sheet was obtained by impregnating the following base material with the following resin composition.

[Resin composition]
The resin composition includes the following (A) modified polyphenylene ether (having a group having an unsaturated double bond at its end), (B) a cross-linking agent (having a carbon-carbon double bond), and (C) a phosphorus compound , and (D) an inorganic filler in the content (parts by mass) shown in Table 1.

(A) modified polyphenylene ether (m-PPE)
・Manufactured by SABIC Innovative Plastics Co., Ltd., product name “SA9000”
(B) Crosslinking agent Nippon Soda Co., Ltd., trade name “B-1000”, polybutadiene oligomer (1,2-polybutadiene homopolymer), number average molecular weight 1200
(C) Phosphorus compound Phosphate ester: Daihachi Chemical Industry Co., Ltd., trade name “PX-200”
・ Phosphinate: Clariant Japan Co., Ltd., trade name “OP935”
(D) Inorganic filler Admatechs Co., Ltd., trade name “SC-2050MTX”, spherical silica, average particle size 0.5 μm
〔Base material〕
・ Glass cloth: manufactured by Nitto Boseki Co., Ltd., trade name “#7628 type”, thickness 173 μm
≪Metal foil≫
As the metal foil, the following copper foil was prepared.

・Copper foil: Mitsui Kinzoku Mining Co., Ltd., product name “3EC-M3-VLP”, thickness 18 μm
<Manufacturing method>
≪Equipment≫
In Examples 1-10 and Comparative Examples 2-3, double-sided copper-clad laminates were produced using a double belt press. In Comparative Example 1, a double-sided copper-clad laminate was manufactured using a batch press apparatus.

≪Heating and pressurizing conditions≫
As shown in Table 1, double-sided copper-clad laminates were produced by changing the heating and pressurizing conditions. Specifically, the temperature rise rate Tv (° C./sec), the temperature rise start temperature Ts (° C.), the maximum temperature Tmax (° C.), the press pressure (MPa) while maintaining the maximum temperature, and the maximum temperature holding time Ht (min), the temperature increase rate Tv (°C/sec), the maximum temperature Tmax (°C), and the maximum temperature holding time Ht (min) were changed. Thermal history Th (°C·min) was calculated from these values.

The double-sided copper-clad laminate obtained as described above was tested under the following test items. Table 1 shows the results.

[warp]
A 17 mm square substrate was obtained by removing the copper foil on both sides of the double-sided copper-clad laminate, and a 15 mm square silicon chip was mounted on one side of this substrate to obtain a sample. The warpage of this sample at 260°C was measured. Specifically, in an atmosphere of 260° C., the sample was placed on a horizontal plane so that the silicon chip was on the upper side and the substrate was on the lower side. Then, the maximum height of the sample from the horizontal plane was measured as warpage. When the sample warps upward, a plus sign is given to the warp value, and when the sample warps downward, a minus sign is given to the warp value.

[Dielectric constant (Dk)]
The dielectric constant of the double-sided copper-clad laminate at 10 GHz was measured by the cavity resonator perturbation method. A network analyzer (manufactured by Keysight Technologies, trade name “N5230A”) was used for the measurement.

[Glass transition temperature (Tg)]
The copper foils on both sides of the double-sided copper-clad laminate were removed. Using this as a sample, the maximum value of tan δ (loss modulus/storage modulus) was defined as the glass transition temperature (Tg) by dynamic viscoelasticity measurement (DMA). A dynamic viscoelasticity measuring device (manufactured by SII Nanotechnology Co., Ltd., trade name "DMS6100") was used for the measurement. The measurement was performed with a tensile module under the condition of temperature increase of 5°C/min.

[Copper foil peeling strength]
The copper foil was peeled off from the insulating layer of the double-sided copper-clad laminate. The peel strength at this time was measured according to JIS C 6481. Specifically, a pattern with a width of 10 mm and a length of 100 mm was formed and peeled off at a speed of 50 mm/min by a tensile tester, and the peel strength at that time was measured.

In Examples 1 to 10, it can be seen that warpage at high temperatures is reduced.

On the other hand, in Comparative Example 1, although the maximum temperature is lower than those of the Examples, the rate of temperature increase is too slow, so that the glass transition temperature (Tg) is too high.

In Comparative Example 2, the maximum temperature holding time was short, and the numerical value of the thermal history was small, so it can be seen that the glass transition temperature (Tg) was too low. That is, an uncured portion remains.

Also, in Comparative Example 3, the numerical value of the thermal history becomes large, so it can be seen that the glass transition temperature (Tg) becomes too high.

1 metal-clad laminate 2 resin sheet 3 metal foil

Claims (6)

A laminate by stacking a resin sheet containing a modified polyphenylene ether compound (A) having a group having an unsaturated double bond at its end and a cross-linking agent (B) having a carbon-carbon double bond and a metal foil and a treatment step of heating the laminate so that the thermal history Th represented by the following formula (1) is in the range of 500 ° C. min or more and 3000 ° C. min or less. fruit,
The average number of groups having an unsaturated double bond per molecule of the modified polyphenylene ether compound (A) is 1 or more and 5 or less,
The percentage of the cross-linking agent (B) is 5% by mass or more and 70% by mass or less with respect to the total amount of the modified polyphenylene ether compound (A) and the cross-linking agent (B).
A method for producing a metal-clad laminate.
(In formula (1), Th (° C. min) indicates the thermal history. Tmax (° C.) indicates the maximum temperature and satisfies 240≦Tmax≦350. Ts (° C.) indicates the temperature at which temperature rise starts. (°C/sec) indicates the rate of temperature rise, Ht (min) indicates the maximum temperature retention time, and satisfies 1.5 ≤ Ht ≤ 6.0.) In the above formula (1), further satisfying 2 ≤ Tv ≤ 8,
The method for manufacturing the metal-clad laminate according to claim 1. In the treatment step, the laminate is heated and pressurized,
The pressure while holding the maximum temperature is 0.5 MPa or more,
A method for producing a metal-clad laminate according to claim 1 or 2. The heating is performed by a roll-to-roll method,
The method for manufacturing the metal-clad laminate according to claim 3. The resin sheet further contains a phosphorus compound,
A method for producing a metal-clad laminate according to any one of claims 1 to 4. The resin sheet further contains an inorganic filler,
A method for producing a metal-clad laminate according to any one of claims 1 to 5.

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