JP2021106248A - Metal-clad laminated plate and circuit board - Google Patents

Abstract

To provide a metal-clad laminated plate and a circuit board that can reduce transmission loss even in high frequency transmission and are excellent in dimension stability.SOLUTION: A metal-clad laminated plate 10 comprises: a first metal layer M1; a first transmission loss prevention layer BS1 that is adjacent to one side thereof; a second metal layer M2; a second transmission loss prevention layer BS2 that is adjacent to one side thereof; and a plurality of resin layers that is interposed between the first transmission loss prevention layer BS1 and the second transmission loss prevention layer BS2. A resin laminate 20 has the first transmission loss prevention layer BS1 and the second transmission loss prevention layer BS2, at least two or more layers of dimensional accuracy maintaining layers PL, and an intermediate transmission loss prevention layer BS3 that is laminated between the dimensional accuracy maintaining layers PL. In the metal-clad laminated plate 10, a total thickness of the dimensional accuracy maintaining layers PL is within a range of 25 to 60% of a total thickness of the resin laminate 20.SELECTED DRAWING: Figure 1

Description

The present invention relates to a metal-clad laminate and a circuit board useful as electronic components.

In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, a flexible printed circuit board (FPC) that is thin and lightweight, has flexibility, and has excellent durability even after repeated bending. The demand for Circuits) is increasing. Since FPC can be mounted three-dimensionally and at high density even in a limited space, its use is expanded to, for example, wiring of moving parts of electronic devices such as HDDs, DVDs, and smartphones, and parts such as cables and connectors. I'm doing it.

In addition to the above-mentioned high density, the high performance of the equipment has advanced, so it is also necessary to cope with the high frequency of the transmission signal. When transmitting a high-frequency signal, if the transmission loss in the transmission path is large, inconveniences such as loss of an electric signal and a long delay time of the signal occur. Therefore, it will be important to reduce transmission loss in FPC in the future.

In order to improve high-frequency transmission characteristics, it has been proposed to use a laminate in which a film made of a fluororesin is laminated on both sides of a polyimide film as an insulating resin layer (Patent Document 1). Since the insulating resin layer of Patent Document 1 uses a fluororesin, it is excellent in terms of dielectric properties, but has a problem in dimensional stability. In particular, when applied to FPC, circuit processing by etching is performed. There is a concern that the dimensional change before and after the heat treatment and the dimensional change before and after the heat treatment will be large.

In order to improve high-frequency transmission characteristics, it has been proposed to bond and laminate two single-sided metal-clad laminates with an adhesive layer introduced with a specific diamine residue, and to control the entire resin layer and the thickness of the adhesive layer. (Patent Document 2). However, in Patent Document 2, since the distance between the low dielectric loss tangent adhesive layer and the metal layer (wiring) is large due to the insulating layer of the single-sided metal-clad laminate, there is room for further improvement in the effect of reducing transmission loss. there were.

Japanese Unexamined Patent Publication No. 2004-216830 JP-A-2018-170417

An object of the present invention is to provide a metal-clad laminate and a circuit board that can reduce transmission loss even in high-frequency transmission and have excellent dimensional stability.

As a result of diligent research, the present inventors provide a transmission loss suppression layer having a low dielectric loss tangent so as to be in contact with a pair of metal layers (wiring), and maintain a plurality of dimensional accuracy between the transmission loss suppression layers. By providing a structure in which the layers are laminated by the intermediate transmission loss suppressing layer and setting the total thickness ratio of the dimensional accuracy maintaining layer to the thickness of the entire resin layer to a certain level or more, the position of the wiring even if the thickness of the entire resin layer is increased. It was found that the deviation can be suppressed, the transmission loss can be reduced, and the dimensional accuracy can be maintained at the same time.

The metal-clad laminate of the present invention includes a first metal layer, a first transmission loss suppressing layer provided in contact with one side of the first metal layer, a second metal layer, and the second metal layer. A second transmission loss suppressing layer provided in contact with one side of the metal layer, and a plurality of resin layers interposed between the first transmission loss suppressing layer and the second transmission loss suppressing layer. It has.
In the metal-clad laminate of the present invention, a resin laminate is formed by the first transmission loss suppressing layer, the second transmission loss suppressing layer, and the plurality of resin layers, and the resin laminate is at least It has two or more dimensional accuracy maintaining layers and an intermediate transmission loss suppressing layer laminated between the dimensional accuracy maintaining layers.
The metal-clad laminate of the present invention has the following conditions i and ii;
i) Dissipation factor at 10 GHz measured by a split post dielectric resonator (SPDR) after humidity control for 24 hours under constant temperature and humidity conditions (normal condition) of 23 ° C. and 50% RH, and the first transmission. Df 1 and the dielectric loss tangent of the loss confinement layer and said second transmission loss confinement _layer, when the dielectric loss tangent of the dimensional accuracy kept layer was Df _2, a relation that Df 1 _{<Df 2;}
ii) The total thickness of the dimensional accuracy maintenance layer is within the range of 25 to 60% of the total thickness of the resin laminate;
Meet.

The circuit board of the present invention includes a first wiring layer, a first transmission loss suppressing layer provided in contact with one side of the first wiring layer, a second wiring layer, and the second wiring. A second transmission loss suppressing layer provided in contact with one side of the layer, and a plurality of resin layers interposed between the first transmission loss suppressing layer and the second transmission loss suppressing layer are provided. ing.
In the circuit board of the present invention, a resin laminate is formed by the first transmission loss suppressing layer, the second transmission loss suppressing layer, and the plurality of resin layers, and the resin laminate has at least two layers. An intermediate transmission loss suppressing layer laminated between the above dimensional accuracy maintaining layer and the dimensional accuracy maintaining layer,
have.
The circuit board of the present invention has the following conditions i and ii;
i) Dissipation factor at 10 GHz measured by a split post dielectric resonator (SPDR) after humidity control for 24 hours under constant temperature and humidity conditions (normal condition) of 23 ° C. and 50% RH, and the first transmission. Df 1 and the dielectric loss tangent of the loss confinement layer and said second transmission loss confinement _layer, when the dielectric loss tangent of the dimensional accuracy kept layer was Df _2, a relation that Df 1 _{<Df 2;}
ii) The total thickness of the dimensional accuracy maintenance layer is within the range of 25 to 60% of the total thickness of the resin laminate;
Meet.

In the metal-clad laminate or circuit board of the present invention, the dimensional accuracy maintenance layer has a minimum storage elastic modulus in the temperature range of 100 ° C. to 250 ° C. even if it is in the range of 1.0 to 8.0 GPa. It may be a low thermal expansion polyimide layer having a thermal expansion coefficient in the range of 15 to 25 ppm / K.

In the metal-clad laminate or circuit substrate of the present invention, a polyimide obtained by reacting an acid anhydride component with a diamine component by a resin constituting the first transmission loss suppressing layer and the second transmission loss suppressing layer. The total amount of the diamine component is 100 mol, and 50 mol or more of diamine diamine in which the two terminal carboxylic acid groups of dimer acid are replaced with a primary aminomethyl group or an amino group is contained. You may.

Since the metal-clad laminate of the present invention is provided with a transmission loss suppression layer having a low dielectric loss tangent so as to be in contact with a pair of metal layers (wiring), transmission loss in high-frequency signal transmission can be effectively suppressed. can. Further, a structure in which a plurality of dimensional accuracy maintaining layers and an intermediate transmission loss suppressing layer are laminated is provided between the transmission loss suppressing layers, and the total thickness ratio of the dimensional accuracy maintaining layers to the total thickness of the resin layer is set to a certain level or more. Therefore, low dielectric constant is realized while ensuring high dimensional stability. Therefore, the metal-clad laminate of the present invention can effectively reduce transmission loss when applied to, for example, a circuit board or the like that transmits a high-frequency signal having a frequency of 10 GHz or more.

It is a schematic diagram which shows the structure of the metal-clad laminate of one Embodiment of this invention. It is a schematic cross-sectional view which shows the structure of the metal-clad laminate of another embodiment of this invention. It is a schematic cross-sectional view which shows the structure of the metal-clad laminate of still another embodiment of this invention. It is a schematic cross-sectional view which shows one structural example of a dimensional accuracy maintenance layer.

Embodiments of the present invention will be described with reference to the drawings as appropriate.

[Metal-clad laminate]
FIG. 1 is a schematic view showing the configuration of a metal-clad laminate according to an embodiment of the present invention. The metal-clad laminate 10 of the present embodiment is
The first metal layer M1 and
The first transmission loss suppressing layer BS1 provided in contact with one side of the first metal layer M1 and
The second metal layer M2 and
A second transmission loss suppressing layer BS2 provided in contact with one side of the second metal layer M2, and
A plurality of resin layers interposed between the first transmission loss suppressing layer BS1 and the second transmission loss suppressing layer BS2, and
It has. The metal-clad laminate 10 is a first transmission loss suppression layer having a low dielectric positive contact at a position closest to the pair of metal layers (first metal layer M1 and second metal layer M2 serving as wiring). Since the BS1 and the second transmission loss suppression layer BS2 are provided, the transmission loss in high frequency signal transmission can be effectively suppressed.
Here, the resin laminate 20 is formed by the first transmission loss suppressing layer BS1, the second transmission loss suppressing layer BS2, and the plurality of resin layers. The resin laminate 20 is laminated between at least two or more dimensional accuracy maintaining layers PL and the dimensional accuracy maintaining layer PL in addition to the first transmission loss suppressing layer BS1 and the second transmission loss suppressing layer BS2. It has an intermediate transmission loss suppression layer BS3.
In this way, by providing a laminated structure of the dimensional accuracy maintaining layer PL and the intermediate transmission loss suppressing layer BS3 between the first transmission loss suppressing layer BS1 and the second transmission loss suppressing layer BS2, high dimensional stability is achieved. Low dielectric constant is realized while ensuring the property.
The resin laminate 20 may have an arbitrary resin layer other than the above, but it is preferably formed only by the resin layer having each of the above functions.

As shown in FIG. 1, the first metal layer M1 and the second metal layer M2 are located on the outermost side, respectively, and are in contact with the innermost layers of the first metal layer M1 and the second metal layer M2 to suppress the first transmission loss and the second transmission loss. Layer BS2 is arranged, and between the first transmission loss suppressing layer BS1 and the second transmission loss suppressing layer BS2, a plurality of resin layers including a plurality of dimensional accuracy maintaining layer PL and an intermediate transmission loss suppressing layer BS3 are provided. It is intervened. Here, the first transmission loss suppression layer BS1 is adjacent to one dimensional accuracy maintenance layer PL, and the second transmission loss suppression layer BS2 is in contact with another dimensional accuracy maintenance layer PL.

The metal-clad laminate 10 shown in FIG. 1 has two layers of dimensional accuracy maintaining layer PL and one layer of intermediate transmission loss suppressing layer BS3, but the dimensional accuracy maintaining layer PL may be two or more layers. The number of layers of the intermediate transmission loss suppression layer BS3 is not particularly limited. For example, as shown in FIG. 2, a configuration having three layers of dimensional accuracy maintenance layer PL and two layers of intermediate transmission loss suppression layer BS3 may be used, or as shown in FIG. 3, a five-layer dimensional accuracy maintenance layer PL and A configuration having four intermediate transmission loss suppression layers BS3 may be used.

In the metal-clad laminate 10, the configurations of the first metal layer M1 and the second metal layer M2 may be the same or different, but they have the same material, the same physical characteristics, and the same thickness. Is preferable.

Further, the configurations of the first transmission loss suppressing layer BS1 and the second transmission loss suppressing layer BS2 may be the same or different, but they may have the same material, the same physical characteristics, and the same thickness. preferable. For example, by making the dielectric loss tangent and the thickness of the first transmission loss suppression layer BS1 and the second transmission loss suppression layer BS2 the same, it becomes easy to design a transmission loss reduction when a high-frequency transmission circuit board is manufactured.

Further, the configurations of the first transmission loss suppression layer BS1, the second transmission loss suppression layer BS2, and the intermediate transmission loss suppression layer BS3 may be the same or different, but the entire resin laminate 20 In order to improve the dielectric properties of the above and effectively suppress the transmission loss of high frequency signals, it is preferable that the same material and the same physical properties are used.

The configurations of the plurality of dimensional accuracy maintaining layers PL may be the same or different, but the same material can be easily designed for mechanical strength and dimensional accuracy when the circuit board is manufactured. , The same physical properties, the same thickness, and the same layer structure are preferable.

The metal-clad laminate 10 satisfies the following conditions i and ii.

Condition i:
Df ₁ a first transmission loss confinement layer BS1 and the second dielectric loss tangent of the transmission loss confinement layer BS2 of, when the dielectric loss tangent of the dimensional accuracy kept layer PL was Df _2, Df 1 <relation that Df _{2.
The dielectric loss tangent Df 1} of the first and second transmission loss suppression layers BS1 and BS2, which are in contact with the first and second metal layers M1 and M2, which should be the circuit wiring which is the transmission path of the high frequency signal, is the dimensional accuracy maintenance layer. By designing the PL to be lower than the dielectric loss tangent Df ₂ , the transmission loss of the high frequency signal can be effectively suppressed. Even when the first transmission loss suppressing layer BS1 and the second transmission loss suppressing layer BS2 have different dielectric loss tangents, it is necessary to satisfy the relationship of _{Df 1 <Df 2 in both cases.} Unless otherwise specified in the present invention, the permittivity and the dielectric loss tangent are measured by a split post dielectric resonator (SPDR) after humidity control for 24 hours under a constant temperature and humidity condition (normal state) of 23 ° C. and 50% RH. It means the permittivity and the dielectric loss tangent at 10 GHz.

From the viewpoint of suppressing the transmission loss of high-frequency signals, the dielectric loss tangent Df ₁ of the first and second transmission loss suppression layers BS1 and BS2 at 10 GHz is preferably 0.005 or less, more preferably 0.003 or less. preferable.

_{The dielectric loss tangent Df 3} of the intermediate transmission loss suppression layer BS3 at 10 GHz, which is measured in the same manner as the condition i, is preferably 0.005 or less, preferably 0.003, from the viewpoint of suppressing the transmission loss of high-frequency signals. The following is more preferable, and most preferably the same as _{the dielectric loss tangent Df 1 of} the first and second transmission loss suppressing layers BS1 and BS2.

_{Further, it is desirable that the dielectric loss tangent Df 2} of the dimensional accuracy maintaining layer PL is as low as possible, but since it is a layer whose main purpose is to maintain dimensional accuracy and mechanical strength, it is assumed that the condition i is satisfied. , It may be preferably 0.012 or less, and more preferably 0.010 or less. Even if the dielectric loss tangent Df ₂ of the dimensional accuracy maintenance layer PL becomes slightly higher, the first and second transmission loss suppression layers BS1 and BS2 and the intermediate transmission loss suppression layer BS3, which are lower dielectric loss tangents, are laminated with each other. This is because the low dielectric constant of the entire resin laminate 20 can be ensured by considering the thickness ratio.

Condition ii:
Total thickness _{T PL} dimensional precision maintenance layer PL is, resin laminate 20 (i.e., the first and second transmission loss confinement layer BS1, BS2, as one or a plurality of intermediate transmission loss confinement layer BS3, a plurality of dimensional accuracy It must be within the range of 25 to 60% of the total thickness T of the maintenance layer PL).
_{By setting the ratio of the total thickness T PL of the} plurality of dimensional accuracy maintaining layers PL to the total thickness T of the resin laminate 20 within the above range, the dimensional accuracy and mechanical strength when the metal-clad laminate 10 is circuit-processed. It is possible to reduce the transmission loss of high-frequency signals while maintaining the above. From this point of view, _{the ratio of the thickness T PL} to the total thickness T is preferably in the range of 25 to 50%.

Here, the thickness of each layer in the resin laminate 20 is not particularly limited because it can be appropriately set according to the purpose of use, but can be exemplified as follows.
The thickness of the first and second transmission loss suppressing layers BS1 and BS2 is preferably in the range of 2 to 100 μm, more preferably in the range of 5 to 75 μm.
The thickness of the dimensional accuracy maintaining layer PL is preferably in the range of 10 to 100 μm, more preferably in the range of 12 to 50 μm.
The thickness of the intermediate transmission loss suppressing layer BS3 is preferably in the range of 12 to 150 μm, more preferably in the range of 25 to 100 μm.
The total thickness T of the resin laminate 20 is preferably in the range of 50 to 300 μm, more preferably in the range of 75 to 200 μm.

Further, in order to lower the dielectric of the entire resin laminate 20, the total thickness T _B of the first and second transmission loss confinement layer BS1, BS2 and the intermediate transmission loss confinement layer BS3, the total thickness of the resin laminate 20 It is preferably in the range of 40 to 75%, more preferably in the range of 50 to 75% with respect to T.

Hereinafter, each layer constituting the metal-clad laminate 10 will be described.

[Metal layer]
The materials of the first metal layer M1 and the second metal layer M2 are not particularly limited, but for example, copper, stainless steel, iron, nickel, berylium, aluminum, zinc, indium, silver, gold, tin, zirconium, etc. Examples thereof include tantalum, titanium, lead, magnesium, manganese and alloys thereof. Of these, copper or copper alloys are particularly preferable. The material of the wiring layer in the circuit board of the present embodiment described later is also the same as that of the first metal layer M1 and the second metal layer M2.

The thickness of the first metal layer M1 and the second metal layer M2 is not particularly limited, but when a metal foil such as a copper foil is used, it is preferably 35 μm or less, more preferably 5 to 25 μm. Good within range. From the viewpoint of production stability and handleability, the lower limit of the thickness of the metal foil is preferably 5 μm. When a copper foil is used, it may be a rolled copper foil or an electrolytic copper foil. Further, as the copper foil, a commercially available copper foil can be used.

Further, the metal foil may be subjected to surface treatment with, for example, siding, aluminum alcoholate, aluminum chelate, silane coupling agent or the like for the purpose of rust prevention treatment or improvement of adhesive strength.

[Transmission loss suppression layer]
The resin constituting the first and second transmission loss suppressing layers BS1 and BS2 and the intermediate transmission loss suppressing layer BS3 (hereinafter, these may be collectively referred to as "transmission loss suppressing layers BS1 to BS3") is glass. The transition temperature (Tg) is preferably 180 ° C. or lower, more preferably 160 ° C. or lower. By setting the glass transition temperature of the transmission loss suppression layers BS1 to BS3 to 180 ° C. or lower, thermocompression bonding at a low temperature becomes possible, so that internal stress generated during lamination can be relaxed and dimensional changes after circuit processing can be suppressed. .. If the Tg of the transmission loss suppressing layers BS1 to BS3 exceeds 180 ° C., the temperature at which they are interposed between the dimensional accuracy maintaining layers PL and adhered becomes high, which may impair the dimensional stability after circuit processing.

The transmission loss suppressing layers BS1 to BS3 preferably have a maximum storage elastic modulus of 1.0 GHz or less in the temperature range of 100 ° C. to 250 ° C. With such a storage elastic modulus, internal stress during thermocompression bonding can be relaxed and dimensional stability after circuit processing can be maintained. In addition, warpage is unlikely to occur even after the solder reflow process after circuit processing.

The resin constituting the first and second transmission loss suppressing layers BS1 and BS2 and the intermediate transmission loss suppressing layer BS3 is preferably polyimide, and is a dimer with respect to 100 mol parts of the total amount of the acid anhydride component and the diamine component. The precursor polyamic acid obtained by reacting with a diamine component containing 50 parts or more of dimerdiamine in which the two terminal carboxylic acid groups of the acid are replaced with a primary aminomethyl group or an amino group is imidized. More preferably, it is a thermoplastic polyimide (hereinafter, may be referred to as "DDA-based polyimide") or a cross-linked cured product thereof. The term polyimide in the present invention means a resin composed of a polymer having an imide group in its molecular structure, such as polyamideimide, polyetherimide, polyesterimide, polysiloxaneimide, and polybenzimidazolimide, in addition to polyimide.

<DDA-based polyimide>
DDA-based polyimide is an aliphatic thermoplastic polyimide, which is highly flexible, has sufficient toughness even when a large amount of liquid crystal polymer filler is added, and has a shape when a resin film is formed. High ability to hold.

The DDA-based polyimide contains a tetracarboxylic acid residue derived from the raw material tetracarboxylic dianhydride and a diamine residue derived from the raw material diamine compound. In the present invention, the tetracarboxylic acid residue represents a tetravalent group derived from a tetracarboxylic dianhydride, and the diamine residue is a divalent group derived from a diamine compound. Represents that. By reacting the raw material tetracarboxylic dianhydride and the diamine compound in approximately equimolar amounts, the type and amount of the tetracarboxylic acid residue and the diamine residue contained in the DDA-based polyimide are compared with the type and amount of the raw material. Can be almost made to correspond.

(Acid anhydride component)
As the DDA-based polyimide, tetracarboxylic dianhydride, which is generally used for thermoplastic polyimide as a raw material, can be used without particular limitation, but the following general formulas (1) and / or (2) are used for the total acid anhydride component. It is preferable to contain 90 mol% or more of the tetracarboxylic dianhydride represented by. In other words, the DDA-based polyimide is a tetracarboxylic dianhydride derived from the tetracarboxylic dianhydride represented by the following general formulas (1) and / or (2) for 100 mol parts of all tetracarboxylic acid residues. It is preferable that the acid residue is contained in an amount of 90 mol parts or more in total. A total of 90 mol or more of tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formulas (1) and / or (2) is added to 100 mol of tetracarboxylic acid residue. By containing it, it is easy to achieve both flexibility and heat resistance of the DDA-based polyimide, which is preferable. If the total amount of tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formulas (1) and / or (2) is less than 90 mol parts, the solvent solubility of the DDA-based polyimide decreases. It becomes a tendency.

In the general formula (1), X represents a single bond or a divalent group selected from the following formula, and in the general formula (2), the cyclic portion represented by Y is a 4-membered ring or a 5-membered ring. , 6-membered ring, 7-membered ring or 8-membered ring.

In the above formula, Z is _{-C 6 H 4 -, - (} CH 2) n- or _{-CH 2 -CH (-O-C (} = O) -CH 3) -CH 2 - are illustrated, n represents 1 Indicates an integer of ~ 20.

Examples of the tetracarboxylic dianhydride represented by the general formula (1) include 3,3', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'. -Benzophenone tetracarboxylic dianhydride (BTDA), 3,3', 4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-oxydiphthalic anhydride (ODPA), 4,4 '-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA), 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), p-phenylenebis (trimerit) Acid monoesteric anhydride) (TAHQ), ethylene glycol bisamhydrotrimeritate (TMEG) and the like can be mentioned. Of these, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA) is particularly preferable. When BTDA is used, the carbonyl group (ketone group) contributes to the adhesiveness, so that the adhesiveness of the DDA-based polyimide can be improved. Further, in BTDA, a ketone group existing in the molecular skeleton may react with an amino group of an amino compound for forming a crosslink, which will be described later, to form a C = N bond, and the effect of improving heat resistance is likely to be exhibited. .. From such a viewpoint, 100 mol parts or more of the tetracarboxylic acid residue derived from BTDA is preferably contained in an amount of 50 parts by mol or more, more preferably 60 parts by mole or more.

Examples of the tetracarboxylic dianhydride represented by the general formula (2) include 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic dianhydride. Dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,4,5-cycloheptantetracarboxylic dianhydride, 1,2,5,6-cyclooctanetetracarboxylic dianhydride Dianhydride and the like can be mentioned.

The DDA-based polyimide contains tetracarboxylic acid residues derived from acid anhydrides other than the tetracarboxylic acid anhydrides represented by the general formulas (1) and (2) above, as long as the effects of the invention are not impaired. Can be contained. Such tetracarboxylic acid residues are not particularly limited, but for example, pyromellitic acid dianhydride, 2,3', 3,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3 , 3'-or 2,3,3', 4'-benzophenone tetracarboxylic acid dianhydride, 2,3', 3,4'-diphenyl ether tetracarboxylic acid dianhydride, bis (2,3-dicarboxyphenyl) ) Ether dianhydride, 3,3'', 4,4''-, 2,3,3'', 4''-or 2,2'',3,3''-p-terphenyltetracarboxylic Acid dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) methane dianhydride, Bis (2,3- or 3,4-dicarboxyphenyl) sulfonate dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride, 1,2,7, 8-1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 2,2-bis (3,4-Dicarboxyphenyl) Tetrafluoropropane dianhydride 1,2,5,6-naphthalene tetracarboxylic acid dianhydride 1,4,5,8-naphthalene tetracarboxylic acid dianhydride 2, 3,6,7-naphthalene tetracarboxylic acid dianhydride 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic acid dianhydride 2,6-or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride 2,3,6,7-(or 1,4,5,8-) tetrachloronaphthalene -1,4,5,8-(or 2,3,6,7-) tetracarboxylic dianhydride 2,3,8,9-,3,4,9,10-4,5,10 , 11- or 5,6,11,12-perylene-tetracarboxylic acid dianhydride, pyrazine-2,3,5,6-tetracarboxylic acid dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic Aromatic tetracarboxylic acid dianhydride such as acid dianhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride, 4,4'-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride. Examples include tetracarboxylic acid residues derived from the substance.

(Diamine component)
As a raw material, DDA-based polyimide contains 50 mol parts or more of diamine diamine in which two terminal carboxylic acid groups of dimer acid are replaced with primary aminomethyl groups or amino groups, based on 100 mol parts of the total amount of the diamine component. A diamine component containing 70 mol parts or more is preferably used. By containing dimer diamine in the above amount, the dielectric property of polyimide is improved, the thermocompression bonding property is improved by lowering the glass transition temperature of polyimide (lower Tg), and the internal stress is relaxed by lowering the elastic modulus. can do.

Dimerdiamine means a diamine in which two terminal carboxylic acid groups (-COOH) of dimer acid are replaced with _{a primary aminomethyl group (-CH 2-} NH ₂ ) or an amino group (-NH _2). do. Dimeric acid is a known dibasic acid obtained by the intermolecular polymerization reaction of unsaturated fatty acids, and its industrial production process is almost standardized in the industry, and unsaturated fatty acids having 11 to 22 carbon atoms are used as clay catalysts. It is obtained by dimerizing with. The industrially obtained dimer acid is mainly composed of a dibasic acid having 36 carbon atoms obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as oleic acid, linoleic acid and linolenic acid. Depending on the degree, it contains an arbitrary amount of monomeric acid (18 carbon atoms), trimeric acid (54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms. Further, although the double bond remains after the dimerization reaction, in the present invention, the dimer acid is also included in which the degree of unsaturation is lowered by the hydrogenation reaction. Dimerdiamine is a diamine compound obtained by substituting a terminal carboxylic acid group of a dibasic acid compound having a carbon number of 18 to 54, preferably 22 to 44, with a primary aminomethyl group or an amino group. Can be defined as.

As a characteristic of dimer diamine, it is possible to impart properties derived from the skeleton of dimer acid. That is, since dimer diamine is an aliphatic of macromolecules having a molecular weight of about 560 to 620, the molar volume of the molecule can be increased and the polar groups of the DDA-based polyimide can be relatively reduced. It is considered that such a feature of the dimer acid type diamine contributes to improving the dielectric property by reducing the dielectric constant and the dielectric loss tangent while suppressing the decrease in the heat resistance of the DDA-based polyimide. In addition, since it has two free-moving hydrophobic chains having 7 to 9 carbon atoms and two chain-like aliphatic amino groups having a length close to 18 carbon atoms, it is necessary to give flexibility to the DDA-based polyimide. However, since the DDA-based polyimide can have an asymmetrical chemical structure or a non-planar chemical structure, it is considered that the dielectric constant can be reduced.

The diamine diamine used in the present invention is preferably purified for the purpose of reducing components other than diamine diamine. The purification method is not particularly limited, but a known method such as a distillation method or precipitation purification is preferable. The diamine diamine before purification can be obtained as a commercially available product, and examples thereof include PRIAMINE 1073 (trade name), PRIAMINE 1074 (trade name), and PRIAMINE 1075 (trade name) manufactured by Croda Japan.

Examples of the diamine compound other than the diamine diamine used in the DDA-based polyimide include aromatic diamine compounds and aliphatic diamine compounds. Specific examples thereof include 1,4-diaminobenzene (p-PDA; paraphenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-n-. Propyl-4,4'-diaminobiphenyl (m-NPB), 4-aminophenyl-4'-aminobenzoate (APAB), 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [ 4- (3-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) phenyl] methane , Bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy)] benzophenone, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2- Bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 3,3'-dimethyl-4,4'- Diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β) -Methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2 , 6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m -Xylylene diamine, p-xylylene diamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4, 4'-Diaminobenzanilide, 4,4'-Zia Minobensanilide, 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, 6-amino-2- (4-aminophenoxy) benzoxazole, 1,3-bis (3-aminophenoxy) ) Examples thereof include diamine compounds such as benzene.

The DDA-based polyimide can be produced by reacting the above-mentioned acid anhydride component and diamine component in a solvent to generate polyamic acid, and then heat-closing the ring. For example, the acid anhydride component and the diamine component are dissolved in an organic solvent in approximately equimolar amounts, and the mixture is stirred at a temperature in the range of 0 to 100 ° C. for 30 minutes to 24 hours to carry out a polymerization reaction to obtain a polyimide precursor. Polyamic acid is obtained. In the reaction, the reaction components are dissolved in the organic solvent so that the precursor produced is in the range of 5 to 50% by weight, preferably in the range of 10 to 40% by weight. Examples of the organic solvent used in the polymerization reaction include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2 -Butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethylsulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diglime, triglime, methanol, ethanol, benzyl alcohol, cresol and the like can be mentioned. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can be used in combination. The amount of such an organic solvent used is not particularly limited, but it should be adjusted so that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50% by weight. Is preferable.

The synthesized polyamic acid is usually advantageous to be used as a reaction solvent solution, but can be concentrated, diluted or replaced with another organic solvent if necessary. In addition, polyamic acid is generally excellent in solvent solubility, and is therefore advantageously used. The viscosity of the polyamic acid solution is preferably in the range of 500 mPa · s to 100,000 mPa · s. If it is out of this range, defects such as thickness unevenness and streaks are likely to occur in the film during coating work by a coater or the like.

The method of imidizing the polyamic acid to form the polyimide is not particularly limited, and for example, a heat treatment such as heating in the solvent under a temperature condition in the range of 80 to 400 ° C. for 1 to 24 hours is preferably adopted. Will be done. Further, the temperature may be heated under a constant temperature condition, or the temperature may be changed in the middle of the process.

In the DDA-based polyimide, the dielectric property, the coefficient of thermal expansion, and the coefficient of thermal expansion can be determined by selecting the types of the acid anhydride component and the diamine component and the molar ratio of each when two or more kinds of the acid anhydride component or the diamine component are applied. The tensile elastic modulus, glass transition temperature, etc. can be controlled. Further, in the DDA-based polyimide, when a plurality of structural units of polyimide are present, it may exist as a block or randomly, but it is preferable that it exists randomly.

The weight average molecular weight of the DDA-based polyimide is preferably in the range of, for example, 10,000 to 200,000, and within such a range, the weight average molecular weight of the polyimide can be easily controlled. Further, for example, when applied as an adhesive for FPC, the weight average molecular weight of the DDA-based polyimide is more preferably in the range of 20,000 to 150,000, and further preferably in the range of 40,000 to 150,000. When applied as an adhesive for FPC, if the weight average molecular weight of the DDA-based polyimide is less than 20,000, the flow resistance tends to deteriorate. On the other hand, when the weight average molecular weight of the DDA-based polyimide exceeds 150,000, the viscosity increases excessively and becomes insoluble in the solvent, causing defects such as uneven thickness of the adhesive layer and streaks during the coating work. It tends to be easy.

The imide group concentration of the DDA-based polyimide is preferably 22% by weight or less, more preferably 20% by weight or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide base portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 22% by weight, the molecular weight of the resin itself becomes small, the low hygroscopicity deteriorates due to the increase in polar groups, and the Tg and elastic modulus increase.

The DDA-based polyimide most preferably has a completely imidized structure. However, a part of the polyimide may be amic acid. ^{The imidization rate is around 1015 cm -1} by measuring the infrared absorption spectrum of the polyimide thin film by the single reflection ATR method using a Fourier transform infrared spectrophotometer (commercially available: FT / IR620 manufactured by JASCO Corporation). It can be calculated from the absorbance of C = O expansion and contraction derived from the imide group of ^{1780 cm -1} based on the benzene ring absorber of.

Other curing resin components such as plasticizers and epoxy resins, curing agents, curing accelerators, inorganic fillers, coupling agents, fillers, solvents, flame retardants and the like are appropriately added to the DDA-based polyimide as optional components. be able to.

[Crosslink formation of DDA-based polyimide]
When the DDA-based polyimide has a ketone group, the amino of the amino compound having the ketone group and at least two primary amino groups as functional groups (hereinafter, may be referred to as "crosslink-forming amino compound"). A crosslinked structure can be formed by reacting the groups to form a C = N bond. By forming the crosslinked structure, the heat resistance of the DDA-based polyimide can be improved. Preferred tetracarboxylic acid anhydrides for forming a DDA-based polyimide having a ketone group include, for example, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA), and diamine compounds include, for example. Aromatic diamines such as 4,4'-bis (3-aminophenoxy) benzophenone (BABP) and 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene (BABB) can be mentioned.

For the purpose of forming a crosslinked structure, in particular, the above-mentioned DDA system containing BTDA residues derived from BTDA in an amount of preferably 50 mol% or more, more preferably 60 mol% or more, based on all tetracarboxylic acid residues. It is preferable to contain polyimide and an amino compound for forming a crosslink. In the present invention, the "BTDA residue" means a tetravalent group derived from BTDA.

Examples of the crosslink-forming amino compound include (I) a dihydrazide compound, (II) an aromatic diamine, and (III) an aliphatic amine. Among these, dihydrazide compounds are preferable. Aliphatic amines other than dihydrazide compounds tend to form crosslinked structures even at room temperature, and there is a concern about storage stability of varnishes, while aromatic diamines need to be heated to a high temperature in order to form crosslinked structures. As described above, when the dihydrazide compound is used, both the storage stability of the varnish and the shortening of the curing time can be achieved at the same time. Examples of the dihydrazide compound include dihydrazide oxalic acid, dihydrazide malonate, dihydrazide succinic acid, dihydrazide glutalide, adipic acid dihydrazide, dihydrazide dihydric acid, dihydrazide sberinate, dihydrazide azeline acid, dihydrazide sebacic acid, and dihydrazide sevacinate. Dihydrazide, dihydrazide fumarate, diglycolic acid dihydrazide, tartrate dihydrazide, malic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoediic acid dihydrazide, 4,4-bisbenzenedihydrazide, 1,4 Dihydrazide compounds such as −naphthoic acid dihydrazide, 2,6-pyridinediacid dihydrazide, and itaconic acid dihydrazide are preferred. The above dihydrazide compounds may be used alone or in combination of two or more.

Further, the amino compounds such as (I) dihydrazide compound, (II) aromatic diamine, and (III) aliphatic amine are, for example, a combination of (I) and (II), a combination of (I) and (III), and the like. It is also possible to use two or more types in combination across categories, such as the combination of (I), (II) and (III).

Further, from the viewpoint of making the network structure formed by cross-linking with the cross-linking amino compound more dense, the cross-linking amino compound used in the present invention has a molecular weight (when the cross-linking amino compound is an oligomer). The weight average molecular weight) is preferably 5,000 or less, more preferably 90 to 2,000, and even more preferably 100 to 1,500. Among these, an amino compound for cross-linking having a molecular weight of 100 to 1,000 is particularly preferable. When the molecular weight of the cross-linking amino compound is less than 90, one amino group of the cross-linking amino compound only forms a C = N bond with the ketone group of the DDA-based polyimide, and the periphery of the remaining amino groups is steric. Since it becomes bulky, the remaining amino groups tend to be difficult to form a C = N bond.

When cross-linking the ketone group in the DDA-based polyimide and the cross-linking amino compound, the above-mentioned cross-linking amino compound is added to the resin solution containing the DDA-based polyimide to form a cross-link with the ketone group in the DDA-based polyimide. Condensation reaction with the primary amino group of the amino compound for use. By this condensation reaction, the resin solution is cured to become a cured product. In this case, the amount of the amino compound for forming a bridge is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, in total of the primary amino group with respect to 1 mol of the ketone group. It can be more preferably 0.03 mol to 0.9 mol, and most preferably 0.04 mol to 0.6 mol. If the amount of the cross-linking amino compound added so that the total number of primary amino groups is less than 0.004 mol with respect to 1 mol of the ketone group, the cross-linking by the cross-linking amino compound is not sufficient, and therefore after curing. Heat resistance tends to be difficult to develop, and when the amount of the cross-linking amino compound added exceeds 1.5 mol, the unreacted cross-linking amino compound acts as a thermoplastic agent, and the heat resistance as the adhesive layer is lowered. Tend to let.

The conditions for the condensation reaction for crosslink formation are as long as the ketone group in the DDA-based polyimide reacts with the primary amino group of the crosslink-forming amino compound to form an imine bond (C = N bond). There are no particular restrictions. The temperature of the heat condensation is, for example, 120 for the purpose of releasing the water generated by the condensation to the outside of the system, or for simplifying the condensation step when the heat condensation reaction is subsequently carried out after the synthesis of the DDA-based polyimide. The range of about 220 ° C. is preferable, and the range of 140 to 200 ° C. is more preferable. The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction is the absorption derived from the ketone group in the polyimide resin near ^{1670 cm -1} by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercially available product: FT / IR620 manufactured by JASCO Corporation). It can be confirmed by the decrease or disappearance of the peak and the appearance of the absorption peak derived from the imine group near ^{1635 cm-1.}

The thermal condensation of the ketone group of the DDA-based polyimide and the primary amino group of the above-mentioned cross-linking amino compound is, for example,
(1) A method of adding an amino compound for cross-linking and heating following the synthesis (imidization) of DDA-based polyimide.
(2) An excess amount of an amino compound is charged in advance as a diamine component, and following the synthesis (imidization) of the DDA-based polyimide, the remaining amino compound that is not involved in imidization or amidization is used as an amino compound for cross-linking. Method of heating with DDA-based polyimide,
Or
(3) A method of heating a DDA-based polyimide composition to which the above-mentioned cross-linking amino compound is added after processing it into a predetermined shape (for example, after applying it to an arbitrary substrate or forming it into a film).
It can be done by such as.

In order to impart heat resistance to DDA-based polyimide, the formation of imine bonds was described in the formation of a crosslinked structure, but the present invention is not limited to this, and examples of the polyimide curing method include epoxy resin, epoxy resin curing agent, maleimide, and the like. It is also possible to blend and cure a compound having an unsaturated bond such as an activated ester resin or a resin having a styrene skeleton.

[Dimensional accuracy maintenance layer]
In order to maintain the mechanical strength of the metal-clad laminate 10, the dimensional accuracy maintenance layer PL has a minimum storage elastic modulus in the temperature range of 100 ° C. to 250 ° C. in the range of 1.0 to 8.0 GPa. It is preferable, and more preferably in the range of 2.0 to 6.0 GHz. If the minimum storage elastic modulus of the dimensional accuracy maintenance layer PL is less than 1.0 GPa, sufficient mechanical strength and dimensional accuracy after circuit processing cannot be obtained. When the minimum value of the storage elastic modulus exceeds 8.0 GPa, warpage is likely to occur during the laminating press.

Further, in order to maintain the dimensional accuracy of the metal-clad laminate 10 when the metal-clad laminate 10 is circuit-processed, the dimensional accuracy maintaining layer PL preferably has a coefficient of thermal expansion (CTE) in the range of 15 to 25 ppm / K, and is preferably 16 to 16. The range of 23 ppm / K is more preferable. If the CTE of the dimensional accuracy maintaining layer PL is less than 15 ppm / K, the metal-clad laminate 10 is likely to warp, and if it exceeds 25 ppm / K, the dimensional accuracy after circuit processing cannot be obtained.

The dimensional accuracy maintenance layer PL is not particularly limited as long as it is composed of a resin having an electrically insulating property, and for example, polyimide, epoxy resin, phenol resin, polyethylene, polypropylene, polytetrafluoroethylene, silicone, ETFE, etc. can be used. Although it can be mentioned, it is preferably composed of polyimide. That is, the dimensional accuracy maintenance layer PL is preferably a low thermal expansion polyimide layer composed of a single layer or a plurality of layers.

When the dimensional accuracy maintenance layer PL is a single-layer polyimide layer, it can have the same configuration as the non-thermoplastic polyimide layer 31 described later. As the single-layer polyimide layer, for example, commercially available products such as Kapton EN (trade name: manufactured by Toray DuPont) and Apical NPI (trade name: manufactured by Kaneka Corporation) can be used.

When the dimensional accuracy maintaining layer PL is composed of a plurality of polyimide layers, for example, as shown in FIG. 4, the dimensional accuracy maintaining layer PL contains resin components on both sides of the non-thermoplastic polyimide layer 31 containing the non-thermoplastic polyimide as the resin component. The structure may be such that the thermoplastic polyimide layer 33 containing the thermoplastic polyimide is laminated. The "non-thermoplastic polyimide" is a polyimide that generally does not soften or show adhesiveness even when heated, but in the present invention, it was measured using a dynamic viscoelasticity measuring device (DMA). A polyimide having a storage elastic modulus of 1.0 × 10 ⁹ Pa or more at ° C. and a storage elastic modulus of 1.0 × 10 ⁸ Pa or more at 350 ° C. Further, the "thermoplastic polyimide" is generally a polyimide in which the glass transition temperature (Tg) can be clearly confirmed, but in the present invention, the storage elastic modulus at 30 ° C. measured using DMA is 1.0. A polyimide having a storage elastic modulus of × 10 ⁹ Pa or more and a storage elastic modulus at 350 ° C. of ^{less than 1.0 × 10 8 Pa.}

Next, a preferable configuration example of the non-thermoplastic polyimide layer 31 and the thermoplastic polyimide layer 33 for forming the dimensional accuracy maintenance layer PL will be described.

Non-thermoplastic polyimide layer:
The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 31 contains a tetracarboxylic acid residue and a diamine residue. The polyimide preferably contains an aromatic tetracarboxylic acid residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine.

(Tetracarboxylic acid residue)
The non-plastic polyimide constituting the non-plastic polyimide layer 31 has 3,3', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 1,4-phenylenebis (TPDA) as tetracarboxylic acid residues. Trimellitic acid monoester) A tetracarboxylic acid residue derived from at least one of the dianhydride (TAHQ) and a pyromellitic dianhydride (PMDA) and 2,3,6,7-naphthalenetetracarboxylic dianhydride. It preferably contains a tetracarboxylic dian residue derived from at least one of the substances (NTCDA).

The tetracarboxylic acid residue derived from BPDA (hereinafter, also referred to as “BPDA residue”) and the tetracarboxylic acid residue derived from TAHQ (hereinafter, also referred to as “TAHQ residue”) are in the order of the polymer. It is easy to form a structure, and the dielectric positivity and hygroscopicity can be reduced by suppressing the movement of molecules. The BPDA residue can impart the self-supporting property of the gel film as the polyamic acid of the polyimide precursor, but on the other hand, it increases the CTE after imidization and lowers the glass transition temperature to lower the heat resistance. It becomes a tendency.

From this point of view, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 31 preferably contains 30 mol parts of the total of BPDA residues and TAHQ residues with respect to 100 mol parts of all tetracarboxylic acid residues. The content is controlled to be contained in the range of 60 mol parts or more, more preferably 40 mol parts or more and 50 mol parts or less. If the total of the BPDA residue and the TAHQ residue is less than 30 mol parts, the formation of the ordered structure of the polymer becomes insufficient, the moisture absorption resistance is lowered, and the reduction of the dielectric loss tangent is insufficient, and 60 mol parts is formed. If it exceeds, the CTE may increase, the amount of change in in-plane retardation (RO) may increase, and the heat resistance may decrease.

Further, a tetracarboxylic acid residue derived from pyromellitic dianhydride (hereinafter, also referred to as “PMDA residue”) and a tetra derived from 2,3,6,7-naphthalenetetracarboxylic dianhydride. Since the carboxylic acid residue (hereinafter, also referred to as "NTCDA residue") has rigidity, it enhances in-plane orientation, suppresses CTE to a low level, controls in-plane retardation (RO), and controls the glass transition temperature. It is a residue that plays a role in controlling. On the other hand, since PMDA residues have a small molecular weight, if the amount is too large, the imide group concentration of the polymer will increase, the polar groups will increase, and the hygroscopicity will increase, and the water content inside the molecular chain will increase. The dielectric positive tangent increases due to the influence. In addition, the NTCDA residue tends to make the film brittle due to the highly rigid naphthalene skeleton, and tends to increase the elastic modulus.
Therefore, in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer, the total of PMDA residues and NTCDA residues is preferably 40 mol parts or more and 70 mol parts or less with respect to 100 mol parts of all tetracarboxylic acid residues. It is contained in the range of 50 mol parts or more and 60 mol parts or less, more preferably 50 to 55 mol parts or less. If the total of PMDA residues and NTCDA residues is less than 40 mol parts, CTE may increase or heat resistance may decrease, and if it exceeds 70 mol parts, the imide group concentration of the polymer becomes high and the polarity The number of groups increases and the low moisture absorption property is impaired, which may increase the dielectric adduct and the film may become brittle and the self-supporting property of the film may decrease.

Further, the total of at least one BPDA residue and TAHQ residue and at least one PMDA residue and NTCDA residue is 80 mol parts or more, preferably 90 parts or more, based on 100 mol parts of all tetracarboxylic acid residues. It is preferably a molar portion or more.

Further, the molar ratio of at least one BPDA residue and TAHQ residue to at least one PMDA residue and NTCDA residue {(BPDA residue + TAHQ residue) / (PMDA residue + NTCDA residue)} is 0. Within the range of 4 or more and 1.5 or less, preferably within the range of 0.6 or more and 1.3 or less, more preferably within the range of 0.8 or more and 1.2 or less, and control the formation of the ordered structure of CTE and the polymer. It is good to do.

Since PMDA and NTCDA have a rigid skeleton, it is possible to control the in-plane orientation of molecules in polyimide as compared with other general acid anhydride components, and suppress the coefficient of thermal expansion (CTE) and glass. It has the effect of improving the transition temperature (Tg). Further, since BPDA and TAHQ have a larger molecular weight than PMDA, the imide group concentration decreases as the charging ratio increases, which is effective in reducing the dielectric loss tangent and the hygroscopicity. On the other hand, when the charging ratio of BPDA and TAHQ increases, the in-plane orientation of the molecules in the polyimide decreases, which leads to an increase in CTE. Furthermore, the formation of an ordered structure in the molecule progresses, and the haze value increases. From this point of view, the total amount of PMDA and NTCDA charged is in the range of 40 to 70 mol parts, preferably in the range of 50 to 60 mol parts, with respect to 100 mol parts of the total acid anhydride component of the raw material. More preferably, it is in the range of 50 to 55 mol parts. If the total amount of PMDA and NTCDA charged is less than 40 mol parts with respect to 100 mol parts of the total acid anhydride component of the raw material, the in-plane orientation of the molecule is lowered, it becomes difficult to reduce the CTE, and Tg. The heat resistance and dimensional stability of the film during heating are reduced due to the decrease in temperature. On the other hand, when the total amount of PMDA and NTCDA charged exceeds 70 mol parts, the hygroscopicity tends to deteriorate or the elastic modulus tends to increase due to the increase in the imide group concentration.

Further, BPDA and TAHQ are effective in suppressing molecular motion, lowering the dielectric loss tangent by lowering the imide group concentration, and lowering the hygroscopicity, but increase the CTE as a polyimide film after imidization. From this point of view, the total amount of BPDA and TAHQ charged is in the range of 30 to 60 mol parts, preferably in the range of 40 to 50 mol parts, with respect to 100 mol parts of the total acid anhydride component of the raw material. good.

Examples of the tetracarboxylic acid residue other than the BPDA residue, TAHQ residue, PMDA residue, and NTCDA residue contained in the non-thermal polyimide constituting the non-thermal polyimide layer 31 include 3,3', 4,4'-Diphenylsulfone tetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, 2,3', 3,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3,3 '-, 2,3,3', 4'-or 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, 2,3', 3,4'-diphenyl ether tetracarboxylic dianhydride, Bis (2,3-dicarboxyphenyl) ether dianhydride, 3,3'', 4,4''-, 2,3,3'', 4''-or 2,2'', 3,3 '' -P-Terphenyltetracarboxylic dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3.4-) Dicarboxyphenyl) methane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) sulfonate dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethanedi Anhydride, 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic acid Dianhydride 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride 2,3,5,6-cyclohexane dianhydride 1,2,5,6-naphthalene tetracarboxylic acid Dianhydride 1,4,5,8-Naphthalenetetracarboxylic dianhydride 4,8-Dimethyl-1,2,3,5,6,7-Hexahydronaphthalene-1,2,5,6- Tetracarboxylic acid dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride, 2,3,6,7-(or 1,4,5, 8-) Tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-) tetracarboxylic dianhydride 2,3,8,9-,3,4,9,10- 4,5,10,11-or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3 , 5,6-tetracarboxylic acid dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic acid dianhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride, 4,4' -Bis (2,3- Dicarboxyphenoxy) Examples thereof include tetracarboxylic acid residues derived from aromatic tetracarboxylic dianhydrides such as diphenylmethane dianhydride and ethylene glycol bisamhydrotrimeritate.

(Diamine residue)
As the diamine residue contained in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 31, a diamine residue derived from the diamine compound represented by the general formula (A1) is preferable.

In the formula (A1), the linking group Z represents a single bond or −COO−, and Y is a monovalent hydrocarbon having 1 to 3 carbon atoms which may be independently substituted with a halogen atom or a phenyl group, or a carbon number of carbon atoms. It represents an alkoxy group of 1 to 3 or a perfluoroalkyl group or an alkenyl group having 1 to 3 carbon atoms, n represents an integer of 0 to 2, and p and q independently represent an integer of 0 to 4. Here, "independently" means that, in the above formula (A1), a plurality of substituents Y and further integers p and q may be the same or different. In the above formula (A1), the hydrogen atom in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (where R ₂ and R ₃ are independently alkyl groups and the like. It may mean any substituent).

The diamine compound represented by the general formula (A1) (hereinafter, may be referred to as “diamine (A1)”) is an aromatic diamine having 1 to 3 benzene rings. Since the diamine (A1) has a rigid structure, it has an action of imparting an ordered structure to the entire polymer. Therefore, a polyimide having low gas permeability and low hygroscopicity can be obtained, and the water content inside the molecular chain can be reduced, so that the dielectric loss tangent can be lowered. Here, as the linking group Z, a single bond is preferable.

Examples of the diamine (A1) include 1,4-diaminobenzene (p-PDA; para-phenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-. Examples thereof include n-propyl-4,4'-diaminobiphenyl (m-NPB) and 4-aminophenyl-4'-aminobenzoate (APAB).

The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 31 contains the diamine residue derived from the diamine (A1) in an amount of preferably 80 mol parts or more, more preferably 80 mol parts or more, based on 100 mol parts of the total diamine residues. It is preferable to contain 85 mol parts or more. By using the diamine (A1) in an amount within the above range, the rigid structure derived from the monomer facilitates the formation of an ordered structure throughout the polymer, resulting in low gas permeability, low hygroscopicity, and low dielectric loss tangent. Non-thermoplastic polyimide can be easily obtained.

Further, when the diamine residue derived from diamine (A1) is in the range of 80 mol parts or more and 85 mol parts or less with respect to 100 mol parts of all diamine residues in the non-thermoplastic polyimide, it is more rigid. It is preferable to use 1,4-diaminobenzene as the diamine (A1) from the viewpoint of the structure having excellent in-plane orientation.

Examples of other diamine residues contained in the non-thermal polyimide constituting the non-thermal polyimide layer 31 include 2,2-bis- [4- (3-aminophenoxy) phenyl] propane and bis [4- ( 3-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) phenyl] methane, bis [ 4- (3-Aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy)] benzophenone, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2-bis- [ 4- (4-Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3 '-Diaminobiphenyl, 3,3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4 '-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl- δ-Aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6- Diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylene Amine, p-xylylene diamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4,4'- Diaminobenzanilide, 4,4'-diaminobenzanilide, 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, 6-amino-2- (4-aminophenoxy) benzoxazole, etc. From aromatic diamine compounds Examples include the derived diamine residue and the diamine residue derived from an aliphatic diamine compound such as a dimer acid type diamine in which the two terminal carboxylic acid groups of dimer acid are replaced with a primary aminomethyl group or an amino group. Be done.

In non-thermoplastic polyimide, thermal expansion is performed by selecting the types of the tetracarboxylic acid residue and the diamine residue and the molar ratio of each when two or more kinds of tetracarboxylic acid residues or diamine residues are applied. The coefficient, storage elastic modulus, tensile elastic modulus, etc. can be controlled. Further, in the non-thermoplastic polyimide, when a plurality of structural units of polyimide are present, they may exist as blocks or randomly, but they are random from the viewpoint of suppressing variation in in-plane retardation (RO). It is preferable to be present in.

By using both the tetracarboxylic acid residue and the diamine residue contained in the non-thermoplastic polyimide as aromatic groups, the dimensional accuracy of the polyimide film in a high temperature environment is improved, and in-plane retardation (RO) is performed. It is preferable because the amount of change in is small.

The imide group concentration of the non-thermoplastic polyimide is preferably 33% or less, more preferably 32% or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide base portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 33%, the molecular weight of the resin itself becomes small, and the decrease in hygroscopicity deteriorates due to the increase in polar groups. By selecting the combination of the acid anhydride and the diamine compound, the orientation of the molecules in the non-thermoplastic polyimide is controlled, thereby suppressing the increase in CTE due to the decrease in the imide group concentration and ensuring low hygroscopicity. ing.

The weight average molecular weight of the non-thermoplastic polyimide is preferably in the range of, for example, 10,000 to 400,000, and more preferably in the range of 50,000 to 350,000. If the weight average molecular weight is less than 10,000, the strength of the film is lowered and the film tends to be brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity is excessively increased, and defects such as film thickness unevenness and streaks tend to occur during the coating operation.

The thickness of the non-thermoplastic polyimide layer 31 is preferably in the range of 6 μm or more and 100 μm or less, preferably 9 μm, from the viewpoint of ensuring the function as a base layer and transportability during manufacturing and coating with the thermoplastic polyimide. It is more preferably in the range of 50 μm or more. If the thickness of the non-thermoplastic polyimide layer 31 is less than the above lower limit value, the electrical insulation and handleability will be insufficient, and if it exceeds the upper limit value, the productivity will decrease.

From the viewpoint of heat resistance, the non-thermoplastic polyimide layer 31 preferably has a glass transition temperature (Tg) of 280 ° C. or higher.

Further, from the viewpoint of suppressing warpage, the coefficient of thermal expansion of the non-thermoplastic polyimide layer 31 is in the range of 1 pm / K or more and 30 ppm / K or less, preferably in the range of 1 ppm / K or more and 25 ppm / K or less, more preferably. It is preferably in the range of 15 ppm / K or more and 25 ppm / K or less.

Further, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer 31 includes, as optional components, other curing resin components such as a plasticizer and an epoxy resin, a curing agent, a curing accelerator, a coupling agent, a filler, and the like. A solvent, a flame retardant, etc. can be appropriately blended. However, some plasticizers contain a large amount of polar groups, which may promote the diffusion of copper from the copper wiring. Therefore, it is preferable not to use the plasticizer as much as possible.

Thermoplastic polyimide layer:
The thermoplastic polyimide constituting the thermoplastic polyimide layer 33 contains a tetracarboxylic acid residue and a diamine residue, and the aromatic tetracarboxylic acid residue and the aromatic are derived from the aromatic tetracarboxylic dianhydride. It preferably contains an aromatic diamine residue derived from the diamine.

(Tetracarboxylic acid residue)
As the tetracarboxylic dian residue used for the thermoplastic polyimide constituting the thermoplastic polyimide layer 33, the same one as exemplified as the tetracarboxylic dian residue in the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is used. be able to.

(Diamine residue)
As the diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 33, a diamine residue derived from a diamine compound represented by the general formulas (B1) to (B7) is preferable.

In the formulas (B1) to (B7), R ₁ independently represents a monovalent hydrocarbon group or an alkoxy group having 1 to 6 carbon atoms, and the linking group A independently represents -O-, -S-, and -CO-. , -SO-, -SO _2- , -COO-, -CH _2- , -C (CH ₃ ) _2- , -NH- or -CONH-, indicating a divalent group, n ₁ being independent. Indicates an integer from 0 to 4. However, the formula (B3) that overlaps with the formula (B2) is excluded, and the formula (B5) that overlaps with the formula (B4) is excluded. Here, "independently", in one of the above formulas (B1) ~ (B7), or in two or more, a plurality of linking groups A, a plurality of R ₁ or a plurality of n _1, the same However, it means that it may be different. In the above formulas (B1) to (B7), the hydrogen atom in the two terminal amino groups may be substituted, for example, -NR ₂ R ₃ (here, R ₂ and R ₃ are independent. It may mean any substituent such as an alkyl group).

The diamine represented by the formula (B1) (hereinafter, may be referred to as "diamine (B1)") is an aromatic diamine having two benzene rings. This diamine (B1) has a high degree of flexibility due to an increase in the degree of freedom of the polyimide molecular chain by having an amino group directly linked to at least one benzene ring and a divalent linking group A at the meta position. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B1) enhances the thermoplasticity of the polyimide. Here, as the linking group A, -O-, -CH _2- , -C (CH ₃ ) _2- , -CO-, -SO _2- , -S- are preferable.

Examples of the diamine (B1) include 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, and 3,3'-diamino. Diphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenylsulfide, 3,3'-diaminobenzophenone, (3,3'- Bisamino) diphenylamine and the like can be mentioned.

The diamine represented by the formula (B2) (hereinafter, may be referred to as "diamine (B2)") is an aromatic diamine having three benzene rings. This diamine (B2) has a high degree of flexibility due to an increase in the degree of freedom of the polyimide molecular chain by having an amino group directly linked to at least one benzene ring and a divalent linking group A at the meta position. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B2) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

Examples of the diamine (B2) include 1,4-bis (3-aminophenoxy) benzene, 3- [4- (4-aminophenoxy) phenoxy] benzeneamine, and 3- [3- (4-aminophenoxy) phenoxy]. Benzene amine and the like can be mentioned.

The diamine represented by the formula (B3) (hereinafter, may be referred to as "diamine (B3)") is an aromatic diamine having three benzene rings. This diamine (B3) has two divalent linking groups A directly linked to one benzene ring at the meta position of each other, so that the degree of freedom of the polyimide molecular chain is increased and the diamine has high flexibility. Therefore, it is considered that it contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B3) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

Examples of the diamine (B3) include 1,3-bis (4-aminophenyloxy) benzene (TPE-R), 1,3-bis (3-aminophenoxy) benzene (APB), and 4,4'-[2-]. Methyl- (1,3-phenylene) bisoxy] bisaniline, 4,4'-[4-methyl- (1,3-phenylene) bisoxy] bisaniline, 4,4'-[5-methyl- (1,3-phenylene) ) Benzene] Bisaniline and the like can be mentioned.

The diamine represented by the formula (B4) (hereinafter, may be referred to as "diamine (B4)") is an aromatic diamine having four benzene rings. This diamine (B4) has high flexibility because the amino group directly linked to at least one benzene ring and the divalent linking group A are in the meta position, which improves the flexibility of the polyimide molecular chain. It is thought to contribute. Therefore, the use of diamine (B4) enhances the thermoplasticity of the polyimide. Here, as the linking group A, -O-, -CH _2- , -C (CH ₃ ) _2- , -SO _2- , -CO-, and -CONH- are preferable.

Diamines (B4) include bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] ether, and bis. [4- (3-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy)] benzophenone, bis [4,4'-(3-aminophenoxy)] benzanilide and the like can be mentioned.

The diamine represented by the formula (B5) (hereinafter, may be referred to as "diamine (B5)") is an aromatic diamine having four benzene rings. This diamine (B5) has two divalent linking groups A directly linked to at least one benzene ring at the meta position of each other, so that the degree of freedom of the polyimide molecular chain is increased and the diamine has high flexibility. It is considered that this contributes to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B5) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

Examples of the diamine (B5) include 4- [3- [4- (4-aminophenoxy) phenoxy] phenoxy] aniline and 4,4'-[oxybis (3,1-phenyleneoxy)] bisaniline. ..

The diamine represented by the formula (B6) (hereinafter, may be referred to as "diamine (B6)") is an aromatic diamine having four benzene rings. This diamine (B6) has high flexibility by having at least two ether bonds, and is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B6) enhances the thermoplasticity of the polyimide. Here, as the linking group A, -C (CH ₃ ) _2- , -O-, -SO _2- , and -CO- are preferable.

Examples of the diamine (B6) include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), bis [4- (4-aminophenoxy) phenyl] ether (BAPE), and bis [4). -(4-Aminophenoxy) phenyl] sulfone (BAPS), bis [4- (4-aminophenoxy) phenyl] ketone (BAPK) and the like can be mentioned.

The diamine represented by the formula (B7) (hereinafter, may be referred to as "diamine (B7)") is an aromatic diamine having four benzene rings. Since this diamine (B7) has highly flexible divalent linking groups A on both sides of the diphenyl skeleton, it is considered to contribute to the improvement of the flexibility of the polyimide molecular chain. Therefore, the use of diamine (B7) enhances the thermoplasticity of the polyimide. Here, as the linking group A, —O— is preferable.

Examples of the diamine (B7) include bis [4- (3-aminophenoxy)] biphenyl and bis [4- (4-aminophenoxy)] biphenyl.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 33 contains diamine residues derived from at least one diamine compound selected from diamines (B1) to diamines (B7) with respect to 100 mol parts of all diamine residues. It may be contained in an amount of 60 mol parts or more, preferably 60 mol parts or more and 99 mol parts or less, and more preferably 70 mol parts or more and 95 mol parts or less. Since diamines (B1) to diamines (B7) have a flexible molecular structure, the flexibility of the polyimide molecular chain is improved by using at least one diamine compound selected from these in an amount within the above range. And can impart thermoplasticity. If the total amount of diamine (B1) to diamine (B7) in the raw material is less than 60 mol parts with respect to 100 mol parts of the total diamine component, sufficient thermoplasticity cannot be obtained due to insufficient flexibility of the polyimide resin.

Further, as the diamine residue contained in the thermoplastic polyimide constituting the thermoplastic polyimide layer 33, a diamine residue derived from the diamine compound represented by the general formula (A1) is also preferable. The diamine compound [diamine (A1)] represented by the formula (A1) is as described in the description of the non-thermoplastic polyimide. Since the diamine (A1) has a rigid structure and has an action of imparting an ordered structure to the entire polymer, it is possible to reduce dielectric loss tangent and hygroscopicity by suppressing the movement of molecules. Further, by using it as a raw material for thermoplastic polyimide, a polyimide having low gas permeability and excellent long-term heat-resistant adhesiveness can be obtained.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 33 contains the diamine residue derived from the diamine (A1) in an amount of preferably 1 mol part or more and 40 mol parts or less, more preferably 5 mol parts or more and 30 mol parts or more. It may be contained within the following range. By using the diamine (A1) in an amount within the above range, an ordered structure is formed in the entire polymer due to the rigid structure derived from the monomer. Therefore, although it is thermoplastic, it has low gas permeability and hygroscopicity and is long-term. A polyimide having excellent heat-resistant adhesiveness can be obtained.

The thermoplastic polyimide constituting the thermoplastic polyimide layer 33 can contain diamine residues derived from diamine compounds other than diamines (A1) and (B1) to (B7) as long as the effects of the invention are not impaired. ..

In thermoplastic polyimide, the coefficient of thermal expansion is selected by selecting the types of the tetracarboxylic acid residue and the diamine residue and the molar ratio of each when two or more types of tetracarboxylic acid residue or diamine residue are applied. , Tension modulus, glass transition temperature, etc. can be controlled. Further, in the thermoplastic polyimide, when a plurality of structural units of polyimide are present, it may exist as a block or randomly, but it is preferable that it exists randomly.

By using both the tetracarboxylic acid residue and the diamine residue contained in the thermoplastic polyimide as aromatic groups, the dimensional accuracy of the polyimide film in a high temperature environment can be improved, and in-plane retardation (RO) can be used. The amount of change can be suppressed.

The imide group concentration of the thermoplastic polyimide is preferably 33% or less, more preferably 32% or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide base portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 33%, the molecular weight of the resin itself becomes small, and the decrease in hygroscopicity deteriorates due to the increase in polar groups. By controlling the orientation of the molecules in the thermoplastic polyimide by selecting the combination of the above diamine compounds, the increase in CTE accompanying the decrease in the imide group concentration is suppressed, and low hygroscopicity is ensured.

The weight average molecular weight of the thermoplastic polyimide is preferably in the range of 10,000 to 400,000, more preferably in the range of 50,000 to 350,000, for example. If the weight average molecular weight is less than 10,000, the strength of the film is lowered and the film tends to be brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity is excessively increased, and defects such as film thickness unevenness and streaks tend to occur during the coating operation.

Since the thermoplastic polyimide constituting the thermoplastic polyimide layer 33 is, for example, an adhesive layer in the insulating resin of the circuit board, a completely imidized structure is most preferable in order to suppress the diffusion of copper. However, a part of the polyimide may be amic acid. ^{The imidization rate is around 1015 cm -1} by measuring the infrared absorption spectrum of the polyimide thin film by the single reflection ATR method using a Fourier transform infrared spectrophotometer (commercially available: FT / IR620 manufactured by JASCO Corporation). It is calculated from the absorbance of C = O expansion and contraction derived from the imide group of ^{1780 cm -1} based on the benzene ring absorber of.

The thickness of the thermoplastic polyimide layer 33 is preferably in the range of 1 μm or more and 10 μm or less, and more preferably in the range of 1 μm or more and 5 μm or less, from the viewpoint of ensuring the adhesive function. If the thickness of the thermoplastic polyimide layer 33 is less than the above lower limit value, the adhesiveness becomes insufficient, and if it exceeds the upper limit value, the dimensional stability tends to deteriorate.

From the viewpoint of suppressing warpage, the thermoplastic polyimide layer 33 has a coefficient of thermal expansion of 30 ppm / K or more, preferably in the range of 30 ppm / K or more and 100 ppm / K or less, and more preferably 30 ppm / K or more and 80 ppm / K or less. It should be within range.

Further, the resin used for the thermoplastic polyimide layer 33 includes, in addition to polyimide, other curing resin components such as a plastic agent and an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, and a coupling agent. Fillers, solvents, flame retardants and the like can be appropriately blended.

The non-thermoplastic polyimide and the thermoplastic polyimide for forming the non-thermoplastic polyimide layer 31 and the thermoplastic polyimide layer 33 are made of polyamide by reacting an acid anhydride component and a diamine component in a solvent in the same manner as the above-mentioned DDA-based polyimide. It can be produced by producing an acid and then heating and closing the ring. In the synthesis of the non-thermoplastic polyimide and the thermoplastic polyimide, the acid anhydride and the diamine may be used alone or in combination of two or more. The coefficient of thermal expansion, adhesiveness, glass transition temperature, etc. can be controlled by selecting the types of acid anhydride and diamine, and the molar ratio of each when two or more types of acid anhydride or diamine are used. ..

<Coefficient of thermal expansion>
In the metal-clad laminate 10, the coefficient of thermal expansion (CTE) of the entire resin laminate 20 is preferably 10 ppm / K or more, preferably in the range of 10 ppm / K or more and 30 ppm / K or less, and more preferably 15 ppm / K or more and 25 ppm. It is within the range of / K or less. If the CTE is less than 10 ppm / K or more than 30 ppm / K, warpage will occur and dimensional stability will decrease. A polyimide layer having a desired CTE can be obtained by appropriately changing the combination of raw materials used, the thickness, and the drying / curing conditions.

<Dissipation factor>
In the metal-clad laminate 10, the dielectric loss tangent (Tanδ) of the entire resin laminate 20 at 10 GHz is preferably 0.02 or less, more preferably 0.0005 or more and 0.01 or less, and further preferably 0.001. It is preferably in the range of 0.008 or less. If the dielectric loss tangent of the entire resin laminate 20 at 10 GHz exceeds 0.02, inconveniences such as loss of electric signals are likely to occur on the transmission path of high-frequency signals when applied to a circuit board. On the other hand, the lower limit of the dielectric loss tangent at 10 GHz of the entire resin laminate 20 is not particularly limited, but the physical property control as the insulating resin layer of the circuit board is taken into consideration.

<Permittivity>
In the metal-clad laminate 10, the resin laminate 20 has a dielectric constant at 10 GHz as a whole in order to ensure impedance matching when applied as an insulating resin layer of a circuit board, for example. The following is preferable. If the dielectric constant of the entire resin laminate 20 at 10 GHz exceeds 4.0, it leads to an increase in dielectric loss when applied to a circuit board, and inconveniences such as loss of electrical signals are likely to occur on the transmission path of high-frequency signals. Become.

[Manufacturing of metal-clad laminates]
The metal-clad laminate 10 is, for example, a resin sheet corresponding to a first transmission loss suppression layer BS1, a second transmission loss suppression layer BS2, a plurality of dimensional accuracy maintenance layers PL, and one or a plurality of intermediate transmission loss suppression layers BS3. These resin sheets can be produced by arranging them between the first metal layer M1 and the second metal layer M2, sticking them together, and thermocompression bonding them.

The metal-clad laminate 10 of the present embodiment obtained as described above is a single-sided FPC or a single-sided FPC by processing a wiring circuit by etching the first metal layer M1 and / or the second metal layer M2. Circuit boards such as double-sided FPCs can be manufactured.

[Circuit board]
The metal-clad laminate 10 is mainly useful as a circuit board material for FPCs, rigid flex circuit boards, and the like. In one embodiment of the present invention, one or both of the first metal layer M1 and the second metal layer M2 of the metal-clad laminate 10 are processed into a pattern by a conventional method to form a wiring layer. A circuit board such as an FPC can be manufactured. Although not shown, this circuit board includes a resin laminate 20 and wiring layers provided on one or both sides of the resin laminate 20, so that transmission loss can be reduced even in high-frequency transmission. It is possible and has excellent dimensional stability.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Measurement of viscosity]
The viscosity was measured using an E-type viscometer (manufactured by Brookfield, trade name; DV-II + Pro) at 25 ° C. The rotation speed was set so that the torque was 10% to 90%, and 2 minutes after the start of the measurement, the value when the viscosity became stable was read.

[Measurement of storage elastic modulus]
A resin sheet having a size of 5 mm × 20 mm was heated from 30 ° C. to 400 ° C. at a heating rate of 4 ° C./min using a dynamic viscoelasticity measuring device (DMA: manufactured by UBM Co., Ltd., trade name; E4000F). The measurement was performed at a frequency of 11 Hz.

[Measurement of coefficient of thermal expansion (CTE)]
A polyimide film having a size of 3 mm × 20 mm was heated from 30 ° C. to 265 ° C. at a constant heating rate while applying a load of 5.0 g using a thermomechanical analyzer (manufactured by Bruker, trade name; 4000SA). Further, after holding at that temperature for 10 minutes, the film was cooled at a rate of 5 ° C./min to obtain an average coefficient of thermal expansion (coefficient of thermal expansion) from 250 ° C. to 100 ° C.

[Measurement of permittivity and dielectric loss tangent]
The dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheet at 10 GHz were measured using a vector network analyzer (manufactured by Agilent, trade name; E8633C) and an SPDR resonator. The material used for the measurement was left to stand for 24 hours under the conditions of temperature; 24 to 26 ° C. and humidity: 45 ° C. to 55% RH.

[Measurement of dimensional change rate]
The dimensional change rate was measured by the following procedure. First, a position measurement target is formed by exposing and developing a dry film resist at 100 mm intervals using a 150 mm square sample. After measuring the dimensions before etching (normal state) in an atmosphere with a temperature of 23 ± 2 ° C and a relative humidity of 50 ± 5%, the copper other than the target of the test piece is etched (liquid temperature 40 ° C or less, time within 10 minutes). Removed by. After standing for 24 ± 4 hours in an atmosphere having a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%, the dimensions after etching are measured. The dimensional change rate for each of the three locations in the vertical direction and the horizontal direction is calculated, and the average value of each is used as the dimensional change rate after etching. The dimensional change rate after etching was calculated by the following formula.

Dimensional change rate after etching (%) = (BA) / A × 100
A; Distance between targets before etching B; Distance between targets after etching

Next, the test piece is heat-treated in an oven at 250 ° C. for 1 hour, and then the distance between the positional targets is measured. The dimensional change rate after etching at each of the three locations in the vertical direction and the horizontal direction is calculated, and the average value of each is used as the dimensional change rate after heat treatment. The heating dimensional change rate was calculated by the following formula.

Heating dimensional change rate (%) = (CB) / B × 100
B; Distance between targets after etching C; Distance between targets after heating

[Measurement of copper foil surface roughness (Rz; 10-point average roughness)]
It was determined using a stylus type surface roughness meter (manufactured by Kosaka Laboratory Co., Ltd., trade name; surf coder ET-3000) under the measurement conditions of Force; 100 μN, Speed; 20 μm, Range; 800 μm. The surface roughness was calculated by a method based on JIS-B0601: 1994.

The abbreviations used in the synthesis examples indicate the following compounds.
BTDA: 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride PMDA: pyromellitic acid dianhydride BPDA: 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride BPADA: 2, 2-Bis [4- (3,4-dicarboxyphenoxy) phenyl] Propane dianhydride DAPE: 4,4'-diaminodiphenyl ether p-PDA: p-phenylenediamine BAPP: 2,2-Bis [4- (4) -Aminophenoxy) Phenyl] Propane m-TB: 2,2'-Dimethyl-4,4'-Diaminobiphenyl TPE-R: 1,3-bis (4-Aminophenoxy) Benzene DDA: Aliphatic diamine having 36 carbon atoms (Manufactured by Claude Japan Co., Ltd., trade name; PRIAMINE1074, amine value: 205 mgKOH / g, mixture of cyclic and chain-structured dimerdiamine, content of dimer component; 95% by weight or more)
OP935: Aluminum phosphinic acid salt (manufactured by Clariant Japan, trade name; Exolit OP935)
N-12: Dodecanedioic acid dihydrazide DMAc: N, N-dimethylacetamide NMP: N-methyl-2-pyrrolidone

(Synthesis Example 1)
312 g of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen. 14.67 g of DAPE (0.073 mol) was dissolved in this reaction vessel with stirring in the vessel. Next, 23.13 g of BTDA (0.072 mol) was added. Then, stirring was continued for 3 hours to prepare a resin solution a of polyamic acid having a solution viscosity of 2,960 mPa · s.

(Synthesis Example 2)
200 g of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen. 1.335 g of m-TB (0.0063 mol) and 10.414 g of TPE-R (0.0356 mol) were dissolved in this reaction vessel with stirring in the vessel. Next, 0.932 g of PMDA (0.0043 mol) and 11.319 g of BPDA (0.0385 mol) were added. Then, stirring was continued for 2 hours to prepare a resin solution b of polyamic acid having a solution viscosity of 1,420 mPa · s.

(Synthesis Example 3)
250 g of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen. 2.561 g of p-PDA (0.0237 mol) and 16.813 g of DAPE (0.0840 mol) were dissolved in this reaction vessel with stirring in the vessel. Next, 18.501 g of PMDA (0.0848 mol) and 6.239 g of BPDA (0.0212 mol) were added. Then, stirring was continued for 3 hours to prepare a resin solution c of polyamic acid having a solution viscosity of 29,500 mPa · s.

(Synthesis Example 4)
250 g of DMAc was placed in a reaction vessel equipped with a thermocouple and a stirrer and capable of introducing nitrogen. 12.323 g of m-TB (0.0580 mol) and 1.886 g of TPE-R (0.0064 mol) were dissolved in this reaction vessel with stirring in the vessel. Next, 8.314 g of PMDA (0.0381 mol) and 7.477 g of BPDA (0.0254 mol) were added. Then, stirring was continued for 3 hours to prepare a resin solution d of polyamic acid having a solution viscosity of 31,500 mPa · s.

(Synthesis Example 5)
<Preparation of resin solution e for adhesive layer>
44.92 g of BTDA (0.139 mol), 75.08 g of DDA (0.141 mol), in a 500 mL 4-neck flask with a nitrogen introduction tube, stirrer, thermocouple, Dean-Stark trap, and condenser. 168 g of NMP and 112 g of xylene were charged and mixed at 40 ° C. for 30 minutes to prepare a polyamic acid solution. The temperature of this polyamic acid solution was raised to 190 ° C., and the mixture was heated and stirred for 4 hours to remove distilled water and xylene from the system. Then, the mixture was cooled to 100 ° C., 112 g of xylene was added and stirred, and further cooled to 30 ° C. to complete imidization to obtain a resin solution e (solid content; 29.5% by weight) for the adhesive layer. ..

(Synthesis Example 6)
<Preparation of resin solution f for adhesive layer>
Except for the raw material composition of 42.51 g BPADA (0.082 mol), 34.30 g DDA (0.066 mol), 6.56 g BAPP (0.016 mol), 208 g NMP and 112 g xylene. , A polyamic acid solution was prepared in the same manner as in Synthesis Example 5. This polyamic acid solution was treated in the same manner as in Synthesis Example 5 to obtain a resin solution f (solid content; 30.0% by weight) for the adhesive layer.

(Production Example 1)
<Preparation of polyimide film>
A resin solution c of polyamic acid is uniformly applied to the surface of one side of the electrolytic copper foil 1 (thickness 12 μm, Rz; 2.1 μm) so that the cured thickness is about 25 μm, and then heated and dried at 120 ° C. The solvent was removed. Further, a stepwise heat treatment from 120 ° C. to 360 ° C. was performed within 30 minutes to complete imidization. The copper foil was etched and removed using an aqueous solution of ferric chloride, and the polyimide film 1 (thickness; 25 μm, Dk; 3.4, Df; 0.0085, CTE; 16 ppm / K, storage elastic modulus minimum value (100 to 100 to 250 ° C.) 2.9 GHz) was prepared.

(Production Example 2)
<Preparation of polyimide film>
Polyimide film 2 (thickness; 25 μm, Dk; 3.3, Df; 0.0034, CTE; 17 ppm / K, minimum storage elastic modulus (100), except that the resin solution d was used, in the same manner as in Production Example 1. ~ 250 ° C.) 3.0 GHz) was prepared.

(Production Example 3)
<Preparation of polyimide film>
The resin solution a was uniformly applied to the surface of one side of the electrolytic copper foil 1 (thickness 12 μm, Rz; 2.1 μm) so that the cured thickness was about 2 to 3 μm, and then heated and dried at 120 ° C. , The solvent was removed. Next, the resin solution d was uniformly applied onto the resin solution d so as to have a thickness of about 21 μm after curing, and then heat-dried at 120 ° C. to remove the solvent. Further, the resin solution a was uniformly applied onto the resin solution a so as to have a thickness of about 2 to 3 μm after curing, and then heat-dried at 120 ° C. to remove the solvent. After forming the three polyamic acid layers in this way, a stepwise heat treatment was performed from 120 ° C. to 360 ° C. to complete imidization. The copper foil layer was etched and removed using an aqueous ferric chloride solution, and the polyimide film 3 (thickness; 25 μm, Dk; 3.4, Df; 0.0052, CTE; 21 ppm / K, storage elastic modulus minimum value (100). ~ 250 ° C.) 2.8 GHz) was prepared.

(Production Example 4)
<Preparation of polyimide film>
The resin solution b was uniformly applied to the surface of one side of the electrolytic copper foil 1 (thickness 12 μm, Rz; 2.1 μm) so that the cured thickness was about 2 to 3 μm, and then heated and dried at 120 ° C. , The solvent was removed. Next, the resin solution d was uniformly applied onto the resin solution d so as to have a thickness of about 21 μm after curing, and then heat-dried at 120 ° C. to remove the solvent. Further, the resin solution b was uniformly applied onto the resin solution b so as to have a thickness of about 2 to 3 μm after curing, and then heat-dried at 120 ° C. to remove the solvent. After forming the three polyamic acid layers in this way, a stepwise heat treatment was performed from 120 ° C. to 360 ° C. to complete imidization. The copper foil layer was etched and removed using an aqueous ferric chloride solution, and the polyimide film 4 (thickness; 25 μm, Dk; 3.3, Df; 0.0032, CTE; 23 ppm / K, storage elastic modulus minimum value (100). ~ 250 ° C.) 2.7 GHz) was prepared.

(Production Example 5)
<Preparation of resin sheet>
169.49 g (50 g as solid content) of the resin solution e is mixed with 1.8 g of N-12 (0.0036 mol) and 12.5 g of OP935, and 6.485 g of NMP and 19.345 g of xylene are added. Diluted to prepare polyimide varnish 1.

A resin sheet 1 is prepared by applying the polyimide varnish 1 to the silicone-treated surface of the release base material so that the thickness after drying is 25 μm, heating and drying at 80 ° C., and peeling from the release base material. did. The permittivity (Dk) and the dielectric loss tangent (Df) of the resin sheet 1 were 2.7 and 0.0023, respectively.

(Production Example 6)
<Preparation of resin sheet>
The resin sheet 2 was adjusted in the same manner as in Production Example 6 except that the thickness after drying was 50 μm. The dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheet 2 were 2.7 and 0.0023, respectively.

(Production Example 7)
<Preparation of resin sheet>
The resin sheet 3 was adjusted in the same manner as in Production Example 6 except that the thickness after drying was 75 μm. The dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheet 3 were 2.7 and 0.0023, respectively.

(Production Example 8)
<Preparation of resin sheet>
The resin sheet 4 was adjusted in the same manner as in Production Example 6 except that the thickness after drying was 5 μm. The permittivity (Dk) and the dielectric loss tangent (Df) of the resin sheet 4 were 2.7 and 0.0023, respectively.

(Production Example 9)
<Preparation of resin sheet>
The resin solution f for the adhesive layer is applied to the silicone-treated surface of the release base material so that the thickness after drying is 25 μm, dried by heating at 80 ° C., and peeled off from the release base material to release the resin. Sheet 5 was prepared. The dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheet 5 were 2.8 and 0.0028, respectively.

(Production Example 10)
<Preparation of resin sheet>
The resin sheet 6 was adjusted in the same manner as in Production Example 10 except that the thickness after drying was 50 μm. The dielectric constant (Dk) and dielectric loss tangent (Df) of the resin sheet 6 were 2.8 and 0.0028, respectively.

[Example 1]
Two electrolytic copper foils 1, two resin sheets 1, one resin sheet 2, and two polyimide films 4 are prepared, and electrolytic copper foil 1 / resin sheet 1 / polyimide film 4 / resin sheet 2 / After laminating the polyimide film 4 / resin sheet 1 / electrolytic copper foil 1 in this order, the double-sided metal-clad laminate 1 was prepared by heat-pressing at 160 ° C. and 4 MPa for 60 minutes. The evaluation results of the double-sided metal-clad laminate 1 are as follows.
Dimensional change rate after etching in the MD direction; -0.05%
Dimensional change rate after etching in the TD direction; -0.04%
Dimensional change rate after heating in MD direction; -0.03%
Dimensional change rate after heating in the TD direction; 0.03%
Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) in the resin laminate 1 (thickness; 150 μm) prepared by etching and removing the electrolytic copper foil 1 in the double-sided metal-clad laminate 1 are 2.9 and 0, respectively. It was 0026. The total thickness of the dimensional accuracy maintenance layer was 33% of the total thickness of the resin laminate 1.

[Example 2]
Two electrolytic copper foils 1, two resin sheets 1, one resin sheet 3, and two polyimide films 4 are prepared, and electrolytic copper foil 1 / resin sheet 1 / polyimide film 4 / resin sheet 3 / After laminating the polyimide film 4 / resin sheet 1 / electrolytic copper foil 1 in this order, the double-sided metal-clad laminate 2 was prepared by heat-pressing at 160 ° C. and 4 MPa for 60 minutes. The evaluation results of the double-sided metal-clad laminate 2 are as follows.
Dimensional change rate after etching in the MD direction; -0.06%
Dimensional change rate after etching in the TD direction; -0.04%
Dimensional change rate after heating in MD direction; -0.04%
Dimensional change rate after heating in the TD direction; 0.04%
Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) in the resin laminate 2 (thickness; 175 μm) prepared by etching and removing the electrolytic copper foil 1 in the double-sided metal-clad laminate 2 are 2.92 and 0. It was 0026. The total thickness of the dimensional accuracy maintenance layer was 29% of the total thickness of the resin laminate 2.

[Example 3]
Two electrolytic copper foils 1, one resin sheet 1, two resin sheets 2, and two polyimide films 4 are prepared, and electrolytic copper foil 1 / resin sheet 2 / polyimide film 4 / resin sheet 1 / After laminating the polyimide film 4 / resin sheet 2 / electrolytic copper foil 1 in this order, the double-sided metal-clad laminate 3 was prepared by heat-pressing at 160 ° C. and 4 MPa for 60 minutes. The evaluation results of the double-sided metal-clad laminate 3 are as follows.
Dimensional change rate after etching in the MD direction; -0.02%
Dimensional change rate after etching in the TD direction; 0.03%
Dimensional change rate after heating in MD direction; -0.06%
Dimensional change rate after heating in the TD direction; -0.02%
Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) in the resin laminate 3 (thickness; 175 μm) prepared by etching and removing the electrolytic copper foil 1 in the double-sided metal-clad laminate 3 are 2.9 and 0. It was 0026. The total thickness of the dimensional accuracy maintenance layer was 29% of the total thickness of the resin laminate 3.

[Example 4]
The double-sided metal-clad laminate 4 was prepared in the same manner as in Example 1 except that the polyimide film 1 was used instead of the polyimide film 4. When the double-sided metal-clad laminate 4 was evaluated, there was no problem in dimensional change. Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) in the resin laminate 4 (thickness; 150 μm) prepared by etching and removing the electrolytic copper foil 1 in the double-sided metal-clad laminate 4 are 2.9 and 0. It was 0044. The total thickness of the dimensional accuracy maintenance layer was 33% of the total thickness of the resin laminate 4.

[Example 5]
The double-sided metal-clad laminate 5 was adjusted in the same manner as in Example 1 except that the polyimide film 2 was used instead of the polyimide film 4. When the double-sided metal-clad laminate 5 was evaluated, there was no problem in dimensional change. Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) in the resin laminate 5 (thickness; 150 μm) prepared by etching and removing the electrolytic copper foil 1 in the double-sided metal-clad laminate 5 are 2.9 and 0, respectively. It was 0027. The total thickness of the dimensional accuracy maintenance layer was 33% of the total thickness of the resin laminate 5.

[Example 6]
The double-sided metal-clad laminate 6 was prepared in the same manner as in Example 1 except that the polyimide film 3 was used instead of the polyimide film 4. When the double-sided metal-clad laminate 6 was evaluated, there was no problem in dimensional change. Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) in the resin laminate 6 (thickness; 150 μm) prepared by etching and removing the electrolytic copper foil 1 in the double-sided metal-clad laminate 6 are 2.9 and 0, respectively. It was 0033. The total thickness of the dimensional accuracy maintenance layer was 33% of the total thickness of the resin laminate 6.

[Example 7]
The double-sided metal-clad laminate 7 was adjusted in the same manner as in Example 1 except that the resin sheet 5 was used instead of the resin sheet 1 and the resin sheet 6 was used instead of the resin sheet 2. When the double-sided metal-clad laminate 7 was evaluated, there was no problem in dimensional change. Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) in the resin laminate 7 (thickness; 150 μm) prepared by etching and removing the electrolytic copper foil 1 in the double-sided metal-clad laminate 7 are 3.0 and 0, respectively. It was 0029. The total thickness of the dimensional accuracy maintenance layer was 33% of the total thickness of the resin laminate 7.

[Example 8]
The double-sided metal-clad laminate 8 was adjusted in the same manner as in Example 1 except that the resin sheet 4 was used instead of the resin sheet 1. When the double-sided metal-clad laminate 8 was evaluated, there was no problem in dimensional change. Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) of the resin laminate 8 (thickness; 110 μm) prepared by etching and removing the electrolytic copper foil 1 on the double-sided metal-clad laminate 8 are 3.0 and 0, respectively. It was 0027. The total thickness of the dimensional accuracy maintenance layer was 45% of the total thickness of the resin laminate 8.

[Comparative Example 1]
Two electrolytic copper foils 1, two resin sheets 2, and one polyimide film 1 are prepared and laminated in the order of electrolytic copper foil 1 / resin sheet 2 / polyimide film 1 / resin sheet 2 / electrolytic copper foil 1. After that, the double-sided metal-clad laminate 9 was adjusted by heat-pressing for 60 minutes under the conditions of 160 ° C. and 4 MPa. The evaluation results of the double-sided metal-clad laminate 9 are as follows.
Dimensional change rate after etching in the MD direction; 0.02%
Dimensional change rate after etching in the TD direction; 0.08%
Dimensional change rate after heating in MD direction; -0.10%
Dimensional change rate after heating in the TD direction; -0.05%
Further, the dielectric constant (Dk) and the dielectric loss tangent (Df) of the resin laminate 9 (thickness; 125 μm) prepared by etching and removing the electrolytic copper foil 1 on the double-sided metal-clad laminate 9 are 2.8 and 0. It was 0035. The total thickness of the dimensional accuracy maintaining layer was 20% of the total thickness of the resin laminate 9.

Although the embodiments of the present invention have been described in detail for the purpose of exemplification, the present invention is not limited to the above embodiments and can be modified in various ways.

10 ... Metal-clad laminate, 20 ... Resin laminate, M1 ... First metal layer, M2 ... Second metal layer, BS1 ... First transmission loss suppression layer, BS2 ... Second transmission loss suppression layer, BS3 ... Intermediate transmission loss suppression layer, PL ... Dimensional accuracy maintenance layer, 31 ... Non-thermoplastic polyimide layer, 33 ... Thermoplastic polyimide layer

Claims (4)

The first metal layer and
A first transmission loss suppressing layer provided in contact with one side of the first metal layer,
The second metal layer and
A second transmission loss suppressing layer provided in contact with one side of the second metal layer,
A plurality of resin layers interposed between the first transmission loss suppressing layer and the second transmission loss suppressing layer, and
With
A resin laminate is formed by the first transmission loss suppressing layer, the second transmission loss suppressing layer, and the plurality of resin layers.
The resin laminate is
At least two or more dimensional accuracy maintenance layers,
An intermediate transmission loss suppression layer laminated between the dimensional accuracy maintenance layers and
Have and
The following conditions i and ii;
i) Dissipation factor at 10 GHz measured by a split post dielectric resonator (SPDR) after humidity control for 24 hours under constant temperature and humidity conditions (normal condition) of 23 ° C. and 50% RH, and the first transmission. Df 1 and the dielectric loss tangent of the loss confinement layer and said second transmission loss confinement _layer, when the dielectric loss tangent of the dimensional accuracy kept layer was Df _2, a relation that Df 1 _{<Df 2;}
ii) The total thickness of the dimensional accuracy maintenance layer is within the range of 25 to 60% of the total thickness of the resin laminate;
A metal-clad laminate that meets the requirements. The dimensional accuracy maintenance layer has a minimum storage elastic modulus in the temperature range of 100 ° C. to 250 ° C. in the range of 1.0 to 8.0 GPa and a thermal expansion coefficient in the range of 15 to 25 ppm / K. The metal-clad laminate according to claim 1, which is a low thermal expansion polyimide layer. The resin constituting the first transmission loss suppressing layer and the second transmission loss suppressing layer is a polyimide obtained by reacting an acid anhydride component and a diamine component, and the total amount of the diamine component is 100 mol. On the other hand, the metal-clad laminate according to claim 1 or 2, which contains 50 mol or more of dimerdiamine in which two terminal carboxylic acid groups of dimer acid are substituted with a primary aminomethyl group or an amino group. The first wiring layer and
A first transmission loss suppressing layer provided in contact with one side of the first wiring layer, and
The second wiring layer and
A second transmission loss suppressing layer provided in contact with one side of the second wiring layer, and
A plurality of resin layers interposed between the first transmission loss suppressing layer and the second transmission loss suppressing layer, and
With
A resin laminate is formed by the first transmission loss suppressing layer, the second transmission loss suppressing layer, and the plurality of resin layers.
The resin laminate is
At least two or more dimensional accuracy maintenance layers,
An intermediate transmission loss suppression layer laminated between the dimensional accuracy maintenance layers and
Have and
The following conditions i and ii;
i) Dissipation factor at 10 GHz measured by a split post dielectric resonator (SPDR) after humidity control for 24 hours under constant temperature and humidity conditions (normal condition) of 23 ° C. and 50% RH, and the first transmission. Df 1 and the dielectric loss tangent of the loss confinement layer and said second transmission loss confinement _layer, when the dielectric loss tangent of the dimensional accuracy kept layer was Df _2, a relation that Df 1 _{<Df 2;}
ii) The total thickness of the dimensional accuracy maintenance layer is within the range of 25 to 60% of the total thickness of the resin laminate;
Circuit board that meets.

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