KR20190114820A - Metal-clad laminate and circuit board - Google Patents

Abstract

The present invention provides a metal-clad laminate having suppressed generation of foaming due to heat treatment at a high temperature. In the metal-clad laminate having a metal layer laminated on a flat surface or both surfaces of an insulating resin layer, polyimide forming a main polyimide layer (A) comprises a diamine residue derived from an aromatic diamine compound containing a fluorine atom and/or an acid anhydride residue derived from an aromatic tetracarboxylic anhydride containing a fluorine atom. A polyimide layer (B) coming in contact with the metal layer has storage elasticity that is more than 1 × 10^8 Pa at 350°C, and further, is formed with polyimide of which a glass transition temperature is more than 280°C.

Description

Metal Sheet Laminates and Circuit Boards {METAL-CLAD LAMINATE AND CIRCUIT BOARD}

TECHNICAL FIELD This invention relates to the field of electronic materials, for example, the metal-clad laminated board used for forming a circuit board, and the circuit board formed by processing this.

The metal-clad laminate used for the manufacture of a flexible printed circuit board (FPC) is a laminate of a metal layer and an insulating resin, which allows fine circuit processing and can be bent in a narrow space. Its use is increasing with the miniaturization and light weight.

The manufacturing method of forming a polyimide layer by heat-processing and imidating the laminated body which produced and repeated applying and drying a polyamic-acid solution on metal foil as a manufacturing method of a flexible metal-clad laminate (casting method) Is known. In the cast method, since the heat treatment is performed at a temperature exceeding the boiling point of the solvent, between the polyimide layer in contact with the metal foil and the adjacent polyimide layer due to the dry state of the polyamic acid layer, the amount of the residual solvent, or the like, Phenomenon such as expansion, peeling, foaming due to the volume expansion of the vaporized solvent and water (imidized water) generated by imidization may occur.

As a prior art for producing a polyimide layer by the casting method, Patent Document 1 discloses forming a thermoplastic polyimide resin layer having a storage modulus of 1 × 10 ⁸ Pa or less at 350 ° C. in a polyimide layer in contact with a metal layer. It is. In this case, the thermoplastic polyimide resin layer has a low elastic modulus at high temperature, and as mentioned above, there is a concern that expansion, peeling, and foaming occur between the polyimide layers during the heat treatment.

Moreover, in patent document 2, in order to ensure the heat resistance which can endure the mounting at the high temperature of a semiconductor element, the storage elastic modulus in 350 degreeC is 1 * 10 <^8> -2 * 10 <^9> Pa in the polyimide layer which contact | connects a metal layer. It is proposed to use high elastic modulus polyimide resin. However, in the Example of patent document 2, the specific disclosure regarding the raw material monomer composition used for the low thermally expandable polyimide layer laminated | stacked on the said high elastic modulus polyimide layer is 2,2'-dimethyl-4,4'- Only one type of the combination of diaminobiphenyl (m-TB) and pyromellitic dianhydride is described.

Moreover, in patent document 3 and patent document 4, in order to suppress moisture absorption and to improve dimensional stability, it is proposed to use the polyimide containing a fluorine atom as a polyimide which comprises a main polyimide layer. However, in patent document 3 and patent document 4, the thermoplastic polyimide with low glass transition temperature (Tg) is used about the polyimide layer which contact | connects a metal layer.

Japanese Patent No.6258921 Japanese Patent No. 4619860 Japanese Patent Publication No. 2010-202681 Japanese Patent No. 5180814

As described above, when the polyimide layer is formed by the cast method, the polyimide layer is expanded, peeled and foamed between the polyimide layers by heat treatment at a high temperature depending on the dry state of the polyamic acid layer and the amount of residual solvent (hereinafter, these " Expansion, peeling, and foaming ”may be referred to collectively as“ foaming ”), which may cause a reduction in the yield and reliability of a metal-clad laminate and a circuit board using the same.

Therefore, the objective of this invention is providing the metal-clad laminated board by which generation | occurrence | production of foaming by the heat processing at high temperature was suppressed.

The reason that foaming occurs between the polyimide layers during the heat treatment at a high temperature is because the solvent and the imidized water contained in the polyamic acid layer are vaporized, thereby increasing the internal pressure between the polyimide layers due to volume expansion. Therefore, while improving the gas permeability of the main polyimide layer, the glass transition temperature (hereinafter may be described as "Tg") of the polyimide layer in contact with the metal layer and the storage elastic modulus in the high temperature region (350 ° C) By improving and improving heat resistance and strength, it discovered that foaming can be suppressed effectively, and completed this invention.

That is, the metal-clad laminate of this invention is a metal-clad laminated board which has an insulated resin layer and the metal layer laminated | stacked on the single side | surface or both surfaces of the said insulated resin layer, The said insulated resin layer is a main polyimide layer (A), and the said It has a some polyimide resin layer laminated | stacked on the single side | surface or both surfaces of a polyimide layer (A), and including the polyimide layer (B) which contact | connects the said metal layer.

In the metal-clad laminate of the present invention, the polyimide constituting the polyimide layer (A) and the polyimide layer (B) is an acid anhydride residue derived from an acid anhydride component and a diamine derived from a diamine component, respectively. It contains residues.

In the metal-clad laminate of the present invention, the polyimide constituting the polyimide layer (A) is an aromatic tetracarboxylic acid containing a diamine residue and / or a fluorine atom derived from an aromatic diamine compound containing a fluorine atom. The acid anhydride residue derived from anhydride may be included.

In the metal-clad laminate of the present invention, the polyimide layer (B) is composed of polyimide having a storage modulus at 350 ° C. of 1 × 10 ⁸ Pa or more and a glass transition temperature (Tg) of 280 ° C. or more. You can do it.

In the metal-clad laminate of the present invention, the polyimide constituting the polyimide layer (A) is a diamine derived from a diamine compound represented by the following general formula (A1) with respect to a total of 100 mol parts of the diamine residues. It may contain 50 mol part or more of a residue.

In general formula (A1), substituent X represents the C1-C3 alkyl group independently substituted by the fluorine atom, and m and n represent the integer of 1-4 independently.

In the metal-clad laminate of the present invention, the polyimide constituting the polyimide layer (A) is a diamine derived from a diamine compound represented by the following general formula (A2) with respect to a total of 100 mol parts of the diamine residues. The residue may be contained within the range of 0 to 50 molar parts.

In general formula (A2), substituent Y independently represents a C1-C3 alkyl group or an alkoxy group, or a C2-C3 alkenyl group, and p and q represent the integer of 0-4 independently.

In the metal-clad laminate of the present invention, the polyimide constituting the polyimide layer (A) contains 50 mol parts or more of acid anhydride residues derived from pyromellitic dianhydride with respect to 100 mol parts of the total acid anhydride residues. It may be done.

In the metal-clad laminate of the present invention, the polyimide constituting the polyimide layer (B) contains 60 moles or more of an acid anhydride residue derived from pyromellitic dianhydride with respect to 100 moles of the total of the acid anhydride residues. It may be done.

In the metal-clad laminate of the present invention, the storage modulus E _A at 350 ° C. of the polyimide layer (A) and the storage modulus E _B at 350 ° C. of the polyimide layer (B) are 0.5 ≦ (E _A / E It may have a relationship of _B ) ≤100.

In the metal-clad laminate of the present invention, the thermal expansion coefficient (CTE) of the polyimide layer (A) may be 30 ppm / k or less, and the thermal expansion coefficient (CTE) of the polyimide layer (B) may be in the range of 0 to 100. do.

The circuit board of this invention is a circuit board which has an insulated resin layer and the metal wiring layer laminated | stacked on the single side | surface or both surfaces of the said insulated resin layer, The said insulated resin layer is a main polyimide layer (A), and the said polyimide layer It has a some polyimide resin layer laminated | stacked on the single side | surface or both surfaces of (A), and including the polyimide layer (B) which contact | connects the said metal wiring layer.

In the circuit board of the present invention, the polyimide constituting the polyimide layer (A) and the polyimide layer (B) is an acid anhydride residue derived from an acid anhydride component and a diamine residue derived from a diamine component, respectively. It contains.

In the circuit board of the present invention, the polyimide constituting the polyimide layer (A) is an aromatic tetracarboxylic anhydride containing a diamine residue and / or a fluorine atom derived from an aromatic diamine compound containing a fluorine atom. Acid anhydride residues derived from

In the circuit board of the present invention, the polyimide layer (B) is composed of a polyimide having a storage modulus at 350 ° C. of 1 × 10 ⁸ Pa or more, and a glass transition temperature (Tg) of 280 ° C. or more.

In the metal-clad laminate of the present invention, the polyimide layer (A) as the main layer is a high gas permeability layer containing a residue containing a fluorine atom derived from a raw material monomer, and the polyimide layer (B) in contact with the metal layer is high. Since it is Tg and is comprised by the polyimide of high storage elastic modulus in high temperature area | region, generation | occurrence | production of foaming is suppressed effectively. Therefore, the yield and reliability of a circuit board, such as a metal-clad laminated board and FPC using this, can be improved.

1 is a characteristic diagram of the storage modulus of the polyimide prepared in Synthesis Example.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

The metal-clad laminate of this embodiment has an insulated resin layer and a metal layer laminated on one side or both sides of the insulated resin layer. The insulated resin layer has a plurality of polyimide resin layers including a main polyimide layer (A) and a polyimide layer (B) laminated on one side or both sides of the polyimide layer (A) and in contact with the metal layer. have. It is preferable that the polyimide layer (B) is provided adjacent to both sides of the polyimide layer (A). The CTE of the insulated resin layer is preferably within the range of ± 5 ppm / K, more preferably within the range of ± 3 ppm / K relative to the CTE of the metal layer. When the CTE difference between the insulating resin layer and the metal layer is within the range of ± 5 ppm / K, internal stress is less likely to occur between the metal layer, for example, the positional accuracy of the metal layer after etching part of the metal layer is removed, and It is advantageous because not only the positional accuracy of the opening part in the insulating resin layer after etching part removal and forming an opening part can be maintained, but large curvature can also be suppressed.

[Polyimide Layer (A)]

The polyimide layer (A) is a main polyimide layer. Here, "main" means having the largest thickness in an insulated resin layer, Preferably it means having a thickness of 50% or more, More preferably, 60% or more with respect to the total thickness of an insulated resin layer.

Moreover, in order to ensure the dimensional stability of an insulated resin layer, a polyimide layer (A) is a low thermal expansion resin layer in 30 ppm / K or less, Preferably it is -5-25 ppm / K in the range.

The polyimide constituting the polyimide layer (A) contains an acid anhydride residue derived from an acid anhydride component and a diamine residue derived from a diamine component, and is particularly derived from an aromatic diamine compound containing a fluorine atom. Acid anhydride residues (fluorine-containing acid anhydride residues) derived from aromatic tetracarboxylic anhydrides containing diamine residues (fluorine-containing diamine residues) and / or fluorine atoms. Since a polyimide is generally manufactured by making an acid anhydride component and a diamine component react, the specific example of a polyimide is understood by demonstrating an acid anhydride and a diamine compound. Hereinafter, preferable polyimide for forming a polyimide layer (A) is demonstrated with an acid anhydride and a diamine compound.

In the present invention, the "diamine component" or "diamine compound" is a hydrogen atom and optionally substituted in the two amino groups of the terminal, such as -NR ₂ R ₃ (wherein, R _2, R ₃ is And an arbitrary substituent such as an alkyl group independently). In addition, in this invention, a "polyimide" may be a homopolymer or a copolymer, and, in the case of a copolymer, may be a block copolymer or a random copolymer.

<Diamine residues>

It is preferable that the polyimide which comprises the polyimide layer (A) contains a fluorine-containing diamine residue. Since the fluorine-containing diamine residue has a group containing a bulky fluorine atom, the gas permeability of the polyimide layer (A) is improved, and the solvent or imidized water vaporized at the time of heat treatment is the polyimide layer (A). It has a high function of facilitating removal to the outside through the light. As a result, a rapid increase in internal pressure between the polyimide layer (A) and the polyimide layer (B) due to volume expansion due to vaporization of residual solvent or imidized water is suppressed, and the occurrence of foaming can be effectively suppressed. have. As a fluorine-containing diamine residue, it is 4,4'- diamino-2,2'-bis (trifluoromethyl) biphenyl (TFMB), 1, 4-bis (4-amino-2- trifluoro, for example). Methylphenoxy) benzene, 3,4-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-bis (2- (trifluoromethyl) -4-aminophenoxy) Biphenyl, 2,2-bis (4- (2- (trifluoromethyl) -4-aminophenoxy) phenyl) hexafluoropropane, 4,4'-bis (3- (trifluoromethyl)- 4-aminophenoxy) biphenyl, 4,4'-bis (3- (trifluoromethyl) -4-aminophenoxy) biphenyl, p-bis (2-trifluoromethyl) -4-aminophenoxy And diamine residues derived from diamine compounds such as c] benzene, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane.

Among the fluorine-containing diamine residues, it is more preferable to contain a diamine residue (hereinafter sometimes referred to as an "A1 residue") derived from the diamine compound represented by the following general formula (A1).

In general formula (A1), substituent X represents the C1-C3 alkyl group independently substituted by the fluorine atom, and m and n represent the integer of 1-4 independently.

Since the A1 residue has a substituent X containing a bulky fluorine atom, the gas permeability of the polyimide layer (A) is improved. Therefore, the function which promotes removal of the solvent and imidized water vaporized at the time of heat processing through the polyimide layer (A), and removing to the outside is high. As a result, a rapid increase in internal pressure between the polyimide layer (A) and the polyimide layer (B) due to volume expansion due to vaporization of residual solvent or imidized water is suppressed, and the occurrence of foaming can be effectively suppressed. have.

In addition, the A1 residue is an aromatic diamine residue, and since the two benzene rings have a biphenyl skeleton connected by a single bond, it is easy to form an ordered structure, and the orientation of the in-plane direction of the molecular chain is promoted, so that the polyimide is the main layer. An increase in the CTE of the layer (A) can be suppressed and the dimensional stability can be enhanced.

From the above viewpoints, the polyimide constituting the polyimide layer (A) preferably contains 50 mole parts or more of the A1 residues relative to a total of 100 mole parts of the total diamine residues, and preferably within 50 to 100 mole parts. More preferred.

Preferred embodiments of the A1 residue include 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl (TFMB) and 3,4-diamino-2,2'-bis (trifluoro And diamine residues derived from diamine compounds such as methyl) biphenyl.

In addition, the polyimide which comprises the polyimide layer (A) contains the diamine residue derived from the diamine compound represented by following General formula (A2) (Hereinafter, it may describe as "A2 residue.") It is preferable.

In general formula (A2), substituent Y independently represents a C1-C3 alkyl group or an alkoxy group, or a C2-C3 alkenyl group, and p and q represent the integer of 0-4 independently.

Since the A2 residue has a biphenyl skeleton, it is easy to form an ordered structure, the orientation of the in-plane direction of the molecular chain is promoted, and the increase in the CTE of the polyimide layer (A) can be suppressed.

From this viewpoint, it is preferable that the polyimide which comprises a polyimide layer (A) contains A2 residue within the range of 0-50 mol part with respect to 100 mol part of total diamine residues, and it is the range of 20-50 mol part It is more preferable to contain inside.

Preferred examples of the A2 residue include 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) and 2,2'-diethyl-4,4'-diaminobiphenyl (m-EB ), 2,2'-diethoxy-4,4'-diaminobiphenyl (m-EOB), 2,2'-dipropoxy-4,4'-diaminobiphenyl (m-POB), 2 , 2'-n-propyl-4,4'-diaminobiphenyl (m-NPB), 2,2'-divinyl-4,4'-diaminobiphenyl (VAB), 4,4'-dia And diamine residues derived from diamine compounds such as minobiphenyl. Among them, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) is particularly preferred because it is easy to form an ordered structure and has a great effect of suppressing an increase in CTE.

The polyimide which comprises the polyimide layer (A) may contain the diamine residue derived from the diamine component generally used for the synthesis | combination of a polyimide as a diamine residue of that excepting the above.

<Acid anhydride residues>

It is preferable that the polyimide which comprises the polyimide layer (A) contains a fluorine-containing acid anhydride residue. Since the fluorine-containing acid anhydride residue has a group containing a bulky fluorine atom, the gas permeability of the polyimide layer (A) is improved, and the solvent or imidized water vaporized at the time of heat treatment is a polyimide layer (A Has a high function of facilitating removal through the outside. As a result, a rapid increase in internal pressure between the polyimide layer (A) and the polyimide layer (B) due to volume expansion due to vaporization of residual solvent or imidized water is suppressed, and the occurrence of foaming can be effectively suppressed. have. Examples of the fluorine-containing acid anhydride residues include acid anhydride residues derived from acid anhydride components such as 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA).

In addition, the polyimide which comprises the polyimide layer (A) is pyromellitic dianhydride (PMDA) represented by following formula (B1), in order to control CTE of a polyimide layer (A) in the said range. It is preferable to contain tetravalent acid anhydride residues (hereinafter sometimes referred to as "PMDA residues") derived from. It is preferable to contain 50 mol part or more with respect to a total of 100 mol parts of all the acid anhydride residues, and, as for PMDA residue, it is more preferable to contain within 60-100 mol part. When PMDA residue is less than 50 mol part, CTE of a polyimide layer (A) becomes high and dimensional stability falls.

The polyimide which comprises the polyimide layer (A) may contain the acid anhydride residue derived from the acid anhydride component generally used for the synthesis | combination of a polyimide as acid anhydride residue of that excepting the above. As such an acid anhydride residue, an aromatic tetracarboxylic acid residue is preferable.

<Thickness of Polyimide Layer (A)>

The thickness of a polyimide layer (A) does not have a restriction | limiting in particular, For example, the inside of the range of 3-25 micrometers is preferable, and the inside of the range of 8-23 micrometers is more preferable. In consideration of the permeability of the vaporized solvent and the imidized water during the heat treatment, or the laser processability and the wet etching property, the thickness of the polyimide layer (A) is preferably thinner. However, since a polyimide layer (A) is a main layer which is responsible for the function which maintains the insulation and strength of an insulated resin layer, the demand which makes a relatively thick film within the range of 25-50 micrometers is also large. As described above, even when the polyimide layer (A) is designed into a thick film having a thickness of 25 µm or more, by adopting the above configuration, it is possible to increase gas permeability, and foaming is generated by a combination with the polyimide layer (B) described later. This is suppressed.

[Polyimide Layer (B)]

The polyimide layer (B) is a highly elastic and high heat resistant resin layer, and the storage modulus at 350 ° C. is 1 × 10 ⁸ Pa or more, preferably in the range of 1 × 10 ⁸ to 1 × 10 ¹⁰ Pa, Moreover, Tg is comprised with polyimide in the range of 280 degreeC or more, Preferably it is 300-500 degreeC.

By making the polyimide layer (B) highly elastic, the solvent and imidized water are vaporized at the time of heat treatment and withstand the increase in the internal pressure between the polyimide layer (A) and the polyimide layer (B) due to volume expansion. Since sufficient strength can be maintained, foaming can be suppressed. When the storage modulus at 350 ° C. is less than 1 × 10 ⁸ Pa, the strength of the polyimide layer (B) is lowered, so that breakage is likely to occur in the polyimide layer (B) due to an increase in the internal pressure at the time of heat treatment, Inhibition of foaming becomes difficult.

Moreover, by making Tg of a polyimide layer (B) high, it becomes difficult to break at the time of heat processing, and foaming can be suppressed. If Tg is less than 280 degreeC, since the heat resistance of a polyimide layer (B) falls, it becomes difficult to suppress foaming. On the other hand, when Tg exceeds 500 degreeC, favorable adhesiveness between a polyimide layer (B) and a metal layer may not be obtained.

As mentioned above, in a polyimide layer (B), generation | occurrence | production of foaming can be suppressed effectively by controlling both storage elastic modulus and Tg at 350 degreeC simultaneously, and making it high elasticity and high heat resistance.

Although the thermal expansion coefficient (CTE) of a polyimide layer (B) does not have a restriction | limiting in particular, For example, it is preferable to exist in the range of 0-100 ppm / K, and the inside of the range of 5-80 ppm / K is more preferable.

The polyimide which comprises the polyimide layer (B) contains the acid anhydride residue derived from an acid anhydride component, and the diamine residue derived from a diamine component. Hereinafter, preferable polyimide is demonstrated with an acid anhydride and diamine.

<Diamine residues>

The polyimide constituting the polyimide layer (B) has an abundance ratio of the PMDA residue, which is an acid anhydride residue, the A1 residue and the A2 residue, and the following general formula (A3) in order to keep the storage modulus and Tg within the above range. The abundance ratio of the diamine residue (Hereinafter, it may describe as "A3 residue", "A4 residue", "A5 residue", and "A6 residue" respectively) derived from the diamine compound represented by (A6) is mentioned later. It is preferable to carry out in a range. Here, the A1 residue and the A2 residue are as described above.

In general formula (A3)-(A6), substituent R <_1> represents a C1-C4 monovalent hydrocarbon group or alkoxy group independently, and linking group A is -O-, -S-, -CO-, -SO-, -SO _2- , -COO-, -CH _2- , -NH- or -CONH- represents, and the linking group B is -O-, -S-, -CO-, -SO-, -COO-, -CH ₂ -, -NH-, -CONH- or a single bond, the linking group C represents -C (CH ₃ ) _2- , and the linking group D is -C (CH ₃ ) _2- , -SO _2- , -C (CF ₃ ) ₂ -is represented, n1 independently represents an integer of 0 to 4;

As a preferable specific example of the diamine residue represented by general formula (A3), 1, 3-bis (3-aminophenoxy) benzene (ABP), 1, 3-bis (4-aminophenoxy) benzene (TPE-R) , 1,4-bis (4-aminophenoxy) benzene (TPE-Q), bis (4-aminophenoxy) -2,5-di-tert-butylbenzene (DTBAB), 1,3-bis [2 And diamine residues derived from diamine compounds such as-(4-aminophenyl) -2-propyl] benzene and 1,4-bis [2- (4-aminophenyl) -2-propyl] benzene.

As a preferable specific example of the diamine residue represented by general formula (A4), the diamine residue derived from diamine compounds, such as 4,4'-bis (4-aminophenoxy) biphenyl (BAPB), is mentioned.

As a preferable specific example of the diamine residue represented by general formula (A5), 1, 3-bis [2- (4-aminophenyl) -2-propyl] benzene (bisaniline M) and (alpha), (alpha) '-bis (4- And diamine residues derived from diamine compounds such as aminophenyl) -1,4-diisopropylbenzene (bisaniline P).

As a preferable specific example of the diamine residue represented by general formula (A6), 2, 2-bis (4-amino phenoxy phenyl) propane (BAPP) and bis [4- (4-amino phenoxy) phenyl] sulfone (BAPS) From diamine compounds such as bis [4- (3-aminophenoxy) phenyl] sulfone (BAPS-M) and 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane (HFBAPP) Derived diamine residues.

Since A2 residue has a biphenyl skeleton common to A1 residue as mentioned above, it is easy to form an order structure and has a function which raises the elasticity modulus of a polyimide layer (B). By making the polyimide layer (B) highly elastic, it is possible to impart sufficient strength to withstand the increase in the internal pressure between the polyimide layer (A) and the polyimide layer (B) during heat treatment, thereby suppressing foaming. Can be.

In addition, since the A2 residue has a biphenyl skeleton in common with the A1 residue essentially included in the polyimide layer (A), the polyimide layer (A) laminated on the polyimide layer (B) by the casting method WHEREIN: Formation of the order structure similar to a polyimide layer (B) is promoted more. That is, since polyimide layer (A) and polyimide layer (B) have similar order structure and orientation, the adhesiveness between these layers becomes stronger, and foaming between layers becomes less likely to occur. As the A2 residue, the diamine residue derived from 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) is most preferred.

On the other hand, from the viewpoint of improving the peel strength with the metal layer and suppressing the decrease in the storage elastic modulus, the [1] PMDA residue is in the range of 85 to 100 mol parts or [2] the PMDA residue relative to 100 mol parts of the total acid anhydride residue. It is preferable to carry out in 50-85 mol part.

[1] In the case where the PMDA residue is in the range of 85 to 100 moles, 15 to 80 moles of at least one selected from the group consisting of A1 residues, A2 residues, A3 residues and A4 residues relative to 100 moles of total diamine residues. It is preferable to set it in the range, and to make at least 1 sort (s) chosen from the group of A5 residue and A6 residue in 20-85 mol part. When the A5 residue and / or A6 residue is less than 20 mol parts, the peel strength with the metal layer tends to be lowered. When the A5 residue and / or A6 residue are more than 85 mol parts, the storage elastic modulus at 350 ° C. is lowered and the solder heat resistance at high temperature tends to be lowered. In addition, it is preferable that at least 1 or more linking groups in said formula (A3) or / and (A4) couple | bond at the para position, and the fall of the storage elastic modulus in 350 degreeC is included by including the coupling position of a para position. It becomes easy to suppress it. As the A3 residue, most preferred are diamine residues derived from 1,3-bis (4-aminophenoxy) benzene (TPE-R) and 1,4-bis (4-aminophenoxy) benzene (TPE-Q). .

[2] When the PMDA residue is in the range of 50 to 85 mol parts, at least one selected from the group of A1 residue, A2 residue, A3 residue, and A4 residue is 50 to 100 based on 100 mol parts of the total diamine residue. It is preferable to set it in the range of mole parts, and to carry out at least 1 sort (s) chosen from the group of A5 residue and A6 residue in the range of 0-50 mole parts. When A5 residue and / or A6 residue exceeds 50 mol part, the storage elastic modulus in 350 degreeC will fall, and there exists a tendency for the solder heat resistance at high temperature to fall.

The polyimide which comprises the polyimide layer (B) may contain the diamine residue derived from the diamine component generally used for the synthesis | combination of a polyimide as diamine residue of that excepting the above. As such diamine residue, an aromatic diamine residue is preferable and there is no restriction | limiting in particular, Although it contributes to improving adhesiveness to the metal layer of a polyimide layer (B), it is 2,2'-bis [4- (4, for example). Tetracarboxylic acid residues derived from -aminophenoxy) phenyl] propane (BAPP) are preferable.

<Acid anhydride residues>

It is preferable that the polyimide which comprises a polyimide layer (B) contains PMDA residue in order to control storage elastic modulus and Tg in the said range, and to suppress foaming. In the polyimide, the storage elastic modulus and Tg of the polyimide layer (B) can be improved by forming the structural unit by a combination of the PMDA residue and the above-mentioned A2 residue and / or A3 residue. In addition, polyimide in the polyimide layer (A) laminated | stacked on the polyimide layer (B) by the casting method by having PMDA residue exist in common in a polyimide layer (A) and a polyimide layer (B) Formation of an ordered structure similar to that of the layer (B) is further promoted. That is, since polyimide layer (A) and polyimide layer (B) have similar order structure and orientation, the adhesiveness between these layers becomes stronger, and foaming between layers becomes less likely to occur.

From the above viewpoints, it is preferable that the polyimide which comprises a polyimide layer (B) contains 50 mol part or more of PMDA residues with respect to a total of 100 mol parts of all the acid anhydride residues, and contains within 50-100 mol part. It is more preferable. If the PMDA residue is less than 50 molar parts, the storage elastic modulus and Tg of the polyimide layer (B) cannot be controlled within the above range, and the formation of an ordered structure is also insufficient, which makes it difficult to suppress foaming.

The polyimide which comprises the polyimide layer (B) may contain the acid anhydride residue derived from the acid anhydride component generally used for synthesis | combination of a polyimide as acid anhydride residue of that excepting the above. There is no restriction | limiting as such an acid anhydride residue, Aromatic tetracarboxylic-acid residue is preferable. In particular, it has a biphenyl skeleton, it is easy to form an order structure, and contributes to the heat resistance of a polyimide layer (B), For example, 3,3 ', 4,4'-biphenyl tetracarboxylic dianhydride ( BPDA), 2,3 ', 3,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, and the like. Preferred is mentioned.

<Thickness of Polyimide Layer (B)>

The thickness of a polyimide layer (B) does not have a restriction | limiting in particular, For example, the inside of the range of 0.5-15 micrometers is preferable, and the inside of the range of 1-10 micrometers is more preferable. When the thermoplastic polyimide is employed in the polyimide layer in contact with the metal layer, as in the metal sheet laminate of Patent Literature 1, the adhesive pressure with the metal layer is maintained and the internal pressure due to vaporization of the residual solvent or imidized water during the heat treatment. From the viewpoint of providing sufficient strength against the rise, the thickness of the polyimide layer (B) is preferably 2 μm or more, which is larger than 0.5 μm of the above lower limit. However, in the metal-clad laminate of the present embodiment, the polyimide layer (B) adopts the above-described high modulus of elasticity and high Tg, and is laminated in combination with the polyimide layer (A) having high gas permeability. It is possible to thin the lower limit of the thickness of the layer (B) to 0.5 µm thinner than 2 µm.

[Relation of Storage Modulus]

In the metal-clad laminate of the present embodiment, the storage modulus E _A at 350 ° C. of the polyimide layer (A) and the storage modulus E _B at 350 ° C. of the polyimide layer (B) are 0.5 ≦ (E _A / E _B It is preferable to have a relationship of? By controlling the relationship between the storage modulus E _A and the storage modulus E _B as described above, the strength difference between the polyimide layer (A) and the polyimide layer (B) is reduced, so that the stress due to the increase in the internal pressure at the time of heat treatment is increased. Concentration on the mid layer (B) is prevented, and generation | occurrence | production of foaming can be suppressed effectively. When the relationship between the storage elastic modulus E _A and the storage elastic modulus E _B is (E _A / E _B )> 100, the difference in strength between the polyimide layer (A) and the polyimide layer (B) becomes too large, and the pressure resistance at the time of heat treatment Since the stress due to the rise is thinner than the polyimide layer (A) and is concentrated on the weak polyimide layer (B), suppression of foaming becomes difficult.

Synthesis of Polyimide

The polyimide which comprises a polyimide layer (A) and a polyimide layer (B) can be manufactured by making an acid anhydride component and a diamine component react in a solvent, heat-closing after generating a polyamic acid. For example, the polyamic acid which is a precursor of a polyimide is obtained by dissolving an acid anhydride component and a diamine component in substantially equimolar in an organic solvent, stirring and reacting for 30 minutes to 24 hours at the temperature within the range of 0-100 degreeC. At the time of reaction, a reaction component is melt | dissolved so that the produced precursor may exist in the range of 5-30 weight% in the organic solvent, Preferably it is in the range of 10-20 weight%. As an organic solvent used for a polymerization reaction, for example, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pi Ralidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme And cresols. Two or more types of these solvents may be used in combination, and further, combinations of aromatic hydrocarbons such as xylene and toluene may be used. The amount of the organic solvent is not particularly limited, but it is preferable to adjust the amount of the organic solvent to the amount of the polyamic acid solution obtained by the polymerization reaction to be about 5 to 30% by weight.

The synthesized polyamic acid is usually advantageously used as a reaction solvent solution, but may be concentrated, diluted or substituted with another organic solvent as necessary. In addition, polyamic acids are advantageously used because they are generally excellent in solvent solubility. The solution viscosity of the polyamic acid is preferably in the range of 500 cps to 100,000 cps. If it is out of this range, defects, such as thickness nonuniformity and a stripe, will arise easily in a film at the time of coating work by a coater etc. The method for synthesizing the polyimide by imidating the polyamic acid is not particularly limited. For example, a heat treatment for heating for 1 to 24 hours at a temperature condition within the range of 80 to 400 ° C. is suitably employed. do.

<Optional ingredient>

The polyimide which comprises a polyimide layer (A) and a polyimide layer (B) can contain arbitrary components, such as a flame retardant and a filler, in the range which does not impair the effect of this invention.

[Metal layer]

It is preferable to use metal foil as a raw material of a metal layer. As the metal constituting the metal foil, for example, copper, aluminum, stainless steel, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zirconium, gold, cobalt, titanium, tantalum, zinc, lead, tin, silicon, bismuth, And metals selected from indium, alloys thereof, and the like. Particularly preferred from the viewpoint of conductivity is copper foil. In addition, when continuously producing the metal clad laminated board of this embodiment, as a metal foil, the elongate metal foil by which the thing of predetermined thickness was wound in roll shape is used.

Moreover, it is preferable that the surface roughness Rz of the surface which directly contacts with the polyimide layer (B) of metal foil exists in the range of 0.05-3.5 micrometers. If it is in this range, even if the internal pressure of the interface of a polyimide layer (A) and a polyimide layer (B) raises, without damaging the adhesive force with a polyimide layer (B), a polyimide layer (B) This is because the fracture is unlikely to occur and foaming is suppressed. When Rz of metal foil exceeds 3.5 micrometers, local breakage of a polyimide layer (B) easily arises by the said internal pressure rise, and it causes foaming. Here, Rz represents the ten point average roughness prescribed | regulated to JISB0601 (1994).

[Manufacture of Laminated Metal Sheets]

The metal-clad laminate of the present embodiment can be produced, for example, by the following method.

First, the coating liquid containing polyamic acid which is a precursor of the polyimide which comprises a polyimide layer (B) is cast on the metal foil used as a metal layer, and it dries and forms a 1st coating film. Then, the coating liquid containing polyamic acid which is a precursor of the polyimide which comprises the main polyimide layer (A) is cast on a 1st coating film, and it dries to form a 2nd coating film. You may further form a coating film by repeating the cast of a coating liquid one by one. For example, when making a polyimide layer three-layered constitution, the coating liquid further containing the polyamic acid which is a precursor of the polyimide which comprises a polyimide layer (B) is cast on a 2nd coating film, and it dries You may form a 3rd coating film. The means to apply | coat is not specifically limited, For example, well-known methods, such as a bar coat system, a gravure coat system, a roll coat system, and a die coat system, can be selected suitably and can be employ | adopted.

In the cast method, it is preferable to cast in the state of the varnish containing a polyamic acid and a solvent. As a solvent, the above-mentioned organic solvent used for the polymerization reaction of polyamic acid is mentioned. A solvent can also be used 1 type or in combination or 2 or more types.

When a coating film contains a solvent, it dries to an appropriate range. The drying temperature at this time is preferably performed at a temperature at which the imidation of the polyamic acid does not proceed, specifically, it is preferably 150 ° C. or less, and preferably within the range of 110 to 140 ° C. In the metal-clad laminate of the present embodiment, since the polyimide layer (A) and the polyimide layer (B) have the above-described configuration, the heat treatment for imidization of the next step is carried out as long as the residual amount of the solvent does not become extremely large. In the process, generation of foaming is suppressed even if the remaining solvent is vaporized.

Then, the laminated body containing a metal layer and a coating film is heat-processed and imidated, for example, the single-sided metal sheet laminated board which has a laminated structure of a metal layer / polyimide layer (B) / polyimide layer (A), or a metal layer / A metal-clad laminate having a laminated structure such as polyimide layer (B) / polyimide layer (A) / polyimide layer (B) can be formed. In the latter case, the metal layer / polyimide layer (B) / polyimide layer (A) / polyimide layer (B) / metal layer is further laminated by laminating metal foil on the polyimide layer (B) by a method such as thermocompression bonding. A double-sided metal sheet laminate having a laminated structure can be formed.

<Circuit board>

The metal-clad laminate of the present embodiment is mainly useful as a material for circuit boards such as FPC. That is, the circuit boards, such as FPC which is one Embodiment of this invention, can be manufactured by processing the metal layer of the metal-clad laminated board of this embodiment to a pattern shape by a conventional method, and forming a wiring layer.

EXAMPLE

An Example is shown below and the characteristic of this invention is demonstrated more concretely. However, the scope of the present invention is not limited to the Example. In addition, in the following Examples, unless otherwise indicated, various measurements and evaluation are based on the following.

[Measurement of Glass Transition Temperature (Tg) and Storage Modulus]

Glass transition temperature (Tg) and storage elastic modulus are the dynamics when the polyimide film obtained by the polyimide precursor resin of each synthesis example was heated up at 5 degree-C / min with the dynamic viscoelasticity measuring apparatus by the rheometric scientific company. Viscoelasticity was measured and Tg (maximum value of tan-delta) and storage elastic modulus at 350 degreeC were calculated | required.

[Measurement of coefficient of thermal expansion (CTE)]

The polyimide film of the size of 3mm x 20mm was heated up from 30 degreeC to 250 degreeC at a constant temperature increase rate, applying the load of 5.0g using a thermomechanical analyzer (Bruker make, brand name; 4000SA), and also at this temperature After holding for 10 minutes, the mixture was cooled at a rate of 5 ° C / min, and an average thermal expansion coefficient (thermal expansion coefficient) from 250 ° C to 100 ° C was obtained.

[Measurement of Peel Strength]

After the copper foil of a single-sided copper clad laminated board (copper foil / resin layer) was circuit-processed (wiring process) to 1.0 mm in width, width; 8 cm x length; Cutting to 4 cm, measurement sample 1 was prepared. The peel strength of the measurement sample fixed the copper foil surface of a measurement sample to an aluminum plate with a double-sided tape using a tensilon tester (Toyo Seiki Seisakusho make, brand name; strograph VE-1D), and copper foil 180 The median intensity | strength at the time of peeling 10 mm from the copper foil and resin layer on the resin coating side at the speed | rate of 50 mm / min in the direction of ° was calculated | required.

[Measurement of Storage Modulus of First Layer]

The storage elastic modulus of a 1st layer uses the polyimide film of the size of 5 mm x 20 mm, and uses the viscoelasticity measuring apparatus (DMA: TA Instruments Co., brand name; RSA3), The temperature increase rate from 30 degreeC to 400 degreeC is 5 degreeC / It measured on the conditions of minutes and the frequency of 1 Hz.

[Evaluation of foam]

When peeling is confirmed between the layers of a polyimide layer (A) and a polyimide layer (B), or a crack generate | occur | produces in a polyimide layer, it is called "with foaming", and the case where there is no peeling or a crack is "no foaming" It was called.

[Measurement of viscosity]

The measurement of the viscosity measured the viscosity in 25 degreeC using the E-type viscosity meter (the Brookfield company make, brand name; DV-II + Pro). The rotation speed was set so that torque might become 10%-90%, and the value when 2 minutes passed after starting a measurement and the viscosity was stabilized was read.

[Measurement of Weight Average Molecular Weight (Mw) of Polyimide]

The weight average molecular weight was measured by the gel permeation chromatograph (made by Tosoh Corporation, HLC-8220GPC). Polystyrene was used as standard and DMAc was used as the developing solvent.

The symbol in an Example is demonstrated.

DMAc: N, N'-dimethylacetamide

PMDA: pyromellitic dianhydride

BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride

6FDA: 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride

ODA: 4,4'-diaminodiphenyl ether

p-PDA: paraphenylenediamine

TFMB: 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl

m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl

BAPP: 2,2'-bis [4- (4-aminophenoxy) phenyl] propane

TPE-R: 1,3-bis (4-aminophenoxy) benzene

Synthesis Examples 1 to 18

Under a nitrogen stream, the diamine compounds shown in Table 1 were dissolved in about 250 to 300 g of solvent DMAc while stirring in a 300 ml separable flask. Then, tetracarboxylic dianhydride shown in Table 1 was added. Thereafter, the solution was stirred at room temperature for 4 hours to carry out a polymerization reaction, thereby obtaining a viscous polyamic acid solution a to r (solid content concentration: 15 wt%). In addition, the numerical value of Table 1 shows the molar ratio of a raw material.

In addition, the measurement result of the storage elastic modulus of the polyimide obtained by imidating the polyamic acid manufactured by the synthesis examples 1, 2, 3, 4, 5, 6, and 7 is shown in FIG. In addition, the code | symbol a, b, c, d, e, f, g in FIG. 1 respond | corresponds to the polyamic-acid solution shown in Table 1. As shown in FIG.

Example 1

The polyamic acid solution c prepared in Synthesis Example 3 was applied onto a copper foil having a thickness of 12 µm and a surface roughness Rz of 0.5 µm so as to have a thickness of 2 µm after curing, and dried at less than 140 ° C for 30 minutes. From this, the polyamic acid solution a prepared in Synthesis Example 1 was applied so that the thickness after curing was 21 μm, and dried at less than 140 ° C. for 1.5 minutes. Furthermore, on these two layers of polyamic acid layers, the polyamic acid solution c prepared in Synthesis Example 3 was applied so that the thickness after curing was 2 μm, and dried at less than 140 ° C. for 30 minutes, followed by a temperature of 150 to 360 ° C. It divided into several steps within the range, and it heated up step by step, and obtained the metal-clad laminated board which has copper foil on the single side | surface of the insulated resin layer. The polyimide layer which comprises an insulated resin layer is a 1st layer which is a polyimide layer (B), the 2nd layer which is a polyimide layer (A), and a polyimide layer (B) in order from the side which contact | connects copper foil. It was set as three layers. About the obtained metal-clad laminate, while measuring the storage elastic modulus and Tg in 350 degreeC of a 1st layer, the peeling strength and the presence or absence of foaming were evaluated. The evaluation results are shown in Table 2.

[Examples 2 to 8 and Comparative Examples 1 to 7]

The metal-clad laminate was made in the same manner as in Example 1 except that the kind of the polyamic acid solution for forming the polyimide layer of the first layer, the second layer, and the third layer was changed to those shown in Tables 2 and 3. It produced and measured the storage elastic modulus and Tg in 350 degreeC of a 1st layer, and evaluated the presence or absence of peeling strength and foaming. The evaluation results are shown in Tables 2 and 3.

Example 9

A metal-clad laminate was obtained in the same manner as in Example 1 except that the thicknesses of the first layer, the second layer, and the third layer were 6 µm, 21 µm, and 6 µm, respectively, but foaming was not confirmed.

Comparative Example 8

Foaming was confirmed when a metal-clad laminate was produced in the same manner as in Comparative Example 5 except that the thicknesses of the first layer, the second layer, and the third layer were 6 µm, 21 µm, and 6 µm, respectively.

Comparative Example 9

Foaming was confirmed when a metal-clad laminate was produced in the same manner as in Comparative Example 6 except that the thicknesses of the first layer, the second layer, and the third layer were 6 µm, 21 µm, and 6 µm, respectively.

Comparative Example 10

Foaming was confirmed when a metal-clad laminate was produced in the same manner as in Comparative Example 7 except that the thicknesses of the first layer, the second layer, and the third layer were 6 µm, 21 µm, and 6 µm, respectively.

As mentioned above, although embodiment of this invention was described in detail for the objective which illustrated, this invention is not restrict | limited to the said embodiment.

Claims (8)

As a metal-clad laminated board which has an insulated resin layer and the metal layer laminated | stacked on the single side | surface or both surfaces of the said insulated resin layer,
The said insulated resin layer is laminated | stacked on the single side | surface or both surfaces of the main polyimide layer (A) and the said polyimide layer (A), and the some polyimide resin layer containing the polyimide layer (B) which contact | connects the said metal layer. With
The polyimide which comprises the said polyimide layer (A) and the said polyimide layer (B) contains the acid anhydride residue derived from an acid anhydride component, and the diamine residue derived from a diamine component, respectively,
The polyimide which comprises the said polyimide layer (A) contains the diamine residue derived from the aromatic diamine compound containing a fluorine atom, and / or the acid anhydride residue derived from the aromatic tetracarboxylic anhydride containing a fluorine atom. and,
The said polyimide layer (B) is a metal clad laminated board characterized by the storage elastic modulus in 350 degreeC being 1 * 10 <^8> Pa or more, and the glass transition temperature being comprised by polyimide whose 280 degreeC or more. The polyimide of claim 1, wherein the polyimide constituting the polyimide layer (A) has a diamine residue derived from a diamine compound represented by the following general formula (A1) with respect to a total of 100 mol parts of the diamine residue: Metal-clad laminate containing more than mole parts.

[In general formula (A1), substituent X represents the C1-C3 alkyl group independently substituted by the fluorine atom, and m and n represent the integer of 1-4 independently.] The polyimide which comprises the said polyimide layer (A) is a diamine residue derived from the diamine compound represented by following General formula (A2) with respect to a total of 100 mol part of the said diamine residues, 0. Metal-clad laminated sheet containing within the range of -50 mol part.

[In general formula (A2), substituent Y independently represents a C1-C3 alkyl group or an alkoxy group, or a C2-C3 alkenyl group, and p and q represent the integer of 0-4 independently.] The acid anhydride according to any one of claims 1 to 3, wherein the polyimide constituting the polyimide layer (A) is derived from pyromellitic dianhydride with respect to a total of 100 moles of the acid anhydride residue. A metal sheet laminated sheet containing 50 mole parts or more of residues. The acid anhydride according to any one of claims 1 to 4, wherein the polyimide constituting the polyimide layer (B) is derived from pyromellitic dianhydride with respect to a total of 100 moles of the acid anhydride residue. A metal sheet laminate containing at least 60 mole parts of a residue. The storage elastic modulus E _A at 350 degrees C of the said polyimide layer (A), and the storage elastic modulus E _B at 350 degrees C of the said polyimide layer (B) are 0.5. _A metal sheet laminate having a relationship of ≦ (E _A / E _B ) ≦ 100. The metal field as described in any one of Claims 1-6 whose thermal expansion coefficient of the said polyimide layer (A) is 30 ppm / k or less, and the thermal expansion coefficient of the said polyimide layer (B) exists in the range of 0-100. Laminates. As a circuit board which has an insulated resin layer and the metal wiring layer laminated | stacked on the single side | surface or both surfaces of the said insulated resin layer,
The said insulated resin layer is laminated | stacked on the single side | surface or both surfaces of the main polyimide layer (A), and the said polyimide layer (A), and the several polyimide number containing the polyimide layer (B) which contact | connects the said metal wiring layer. Have strata,
The polyimide which comprises the said polyimide layer (A) and the said polyimide layer (B) contains the acid anhydride residue derived from an acid anhydride component, and the diamine residue derived from a diamine component, respectively,
The polyimide which comprises the said polyimide layer (A) contains the diamine residue derived from the aromatic diamine compound containing a fluorine atom, and / or the acid anhydride residue derived from the aromatic tetracarboxylic anhydride containing a fluorine atom. and,
The said polyimide layer (B) is a circuit board characterized by being made from polyimide whose storage elastic modulus in 350 degreeC is 1 * 10 <^8> Pa or more, and glass transition temperature is 280 degreeC or more.

Images