JP2020044690A - Metal-clad laminate and patterned metal-clad laminate - Google Patents

Abstract

To provide a metal-clad laminate high in dimensional stability before and after etching, and having suppressed generation of waving, while setting heat expansion coefficient CTEof a polyimide layer smaller than heat expansion coefficient CTEof the metal layer.SOLUTION: A metal-clad laminate having a polyimide layer and a metal layer laminated on at least one surface of the polyimide layer, realizing (i) thickness of the polyimide layer is in a range of 1 to 15 μm, (ii) the polyimide layer contains a non-thermoplastic polyimide layer, and glass transition temperature Tg of non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is 330°C or less, and (iii) heat expansion coefficient of the polyimide layer CTEand heat expansion coefficient of the metal layer CTEhas a relationship of the following formula (a). 2 ppm/K≤CTE-CTE≤8 ppm/K (a).SELECTED DRAWING: None

Description

  The present invention relates to metal-clad laminates and patterned metal-clad laminates useful as, for example, circuit board materials.

  2. Description of the Related Art In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, a flexible printed wiring board (FPC) that is thin and lightweight, has flexibility, and has excellent durability even when repeatedly bent. Circuits) is increasing in demand. Since FPCs can be mounted three-dimensionally and at high density even in a limited space, their applications are expanding to, for example, wiring of movable parts of electronic devices such as HDDs, DVDs and smartphones, and components such as cables and connectors. I am doing it.

  In addition to the above-described high density, as the performance of the equipment has been improved, there is a need for a material that has a smaller dimensional change due to the influence of moisture absorption and thermal expansion than ever before. A liquid crystal polymer is a material characterized by a low moisture absorption, a low dielectric constant, and a low dielectric loss tangent. An FPC using a liquid crystal polymer as a dielectric layer is used as a high-frequency FPC compatible with high-speed communication and the like. However, although liquid crystal polymers have excellent dielectric properties, there is room for improvement in heat resistance and adhesion to metal foils.

  As a material replacing the liquid crystal polymer, Patent Literature 1 discloses a metal clad having a polyimide layer having improved dielectric properties and hygroscopicity by using an aliphatic diamine typified by a dimer acid type diamine as a monomer as a raw material of the polyimide. Laminates have been proposed. However, since the polyimide of Patent Document 1 uses an aliphatic diamine as a raw material monomer, it is disclosed that a flame retardant is blended. In addition, the use of the aliphatic diamine may cause a decrease in dimensional stability in a heating step at the time of FPC production and a possibility of swelling due to thermal decomposition.

  In addition, as electronic devices have become smaller, lighter, and more multifunctional, electronic components such as ICs and LSIs have become more highly integrated, and their forms are rapidly changing to more pins and smaller sizes. For this reason, there is a growing demand for a wiring board or the like used for directly mounting an IC or the like. In particular, it is required to lower the thermal expansion coefficient of an insulating resin film constituting an FPC.

  By the way, in the photolithography process for the metal-clad laminate and the process of FPC mounting using the metal-clad laminate, various processes such as joining, cutting, exposure, and etching are performed based on the alignment marks provided on the metal-clad laminate. Is performed. In order to maintain the processing accuracy in these steps, it is necessary to improve the dimensional stability before and after etching in consideration of the difference in the coefficient of thermal expansion (CTE) between the metal foil and the resin layer.

JP 2015-199328 A

In a metal-clad laminate in which a metal layer and a polyimide layer are laminated, it is usual that the coefficient of thermal expansion CTE _{P of the} polyimide layer is larger than the coefficient of thermal expansion CTE _M of the metal layer. Meanwhile, after forming a metal-clad laminate to the circuit board, for example, in the heating process step during a semiconductor device mounting, to reduce the dimensional change of the polyimide layer, that you minimize the thermal expansion coefficient CTE _P of the polyimide layer Is advantageous. However, if designed to have a small thermal expansion coefficient CTE _P of the polyimide layer than the thermal expansion coefficient CTE _M of the metal layer, or reduced dimensional stability dimensional change after etching the metal layer is increased, waviness is generated For example, there is a concern that the reliability of a circuit board such as an FPC may be reduced.

An object of the present invention, while smaller thermal expansion coefficient CTE _P of the polyimide layer than the thermal expansion coefficient CTE _M of the metal layer, small dimensional change before and after etching, the metal-clad occurrence of waviness of the polyimide layer is suppressed It is to provide a laminate.

The present inventors have conducted intensive studies and found that, in a metal-clad laminate in which a metal layer and a polyimide layer are laminated, the thermal expansion coefficient CTE _P of the polyimide layer is designed to be smaller than the thermal expansion coefficient CTE _M of the metal layer. However, the present inventors have found that it is possible to improve the dimensional stability before and after etching by lowering the glass transition temperature of the polyimide constituting the polyimide layer, and completed the present invention.

That is, the metal-clad laminate of the present invention includes a polyimide layer and a metal layer laminated on at least one surface of the polyimide layer.
The metal-clad laminate of the present invention has the following conditions (i) to (iii);
(I) the thickness of the polyimide layer is in the range of 1 to 15 μm;
(Ii) the polyimide layer includes a non-thermoplastic polyimide layer having a glass transition temperature Tg of 330 ° C. or lower;
(Iii) The coefficient of thermal expansion CTE _P of the polyimide layer and the coefficient of thermal expansion CTE _M of the metal layer satisfy the relationship of the following equation (a):
2 ppm / K ≦ CTE _M −CTE _P ≦ 8 ppm / K (a)
It satisfies.

Metal-clad laminate of the present invention has a thermal expansion coefficient CTE _P of the polyimide layer is less than 15 ppm / K, the thermal expansion coefficient CTE _M of the metal layer may be less than 20 ppm / K.

The metal-clad laminate of the present invention comprises the following steps (1) to (6);
(1) a step of preparing a test piece by cutting the metal-clad laminate to a predetermined length;
(2) Assuming that the vertical direction of the test piece is the MD direction and the horizontal direction is the TD direction, a virtual square having sides parallel to the MD direction and the TD direction in the test piece is assumed;
Four corners in the square,
Forming a plurality of marks in a linear array on four sides of the square in the MD direction and the TD direction at equal intervals based on the two corners of the end of the one side,
(3) a first measurement step of measuring positions of the plurality of marks and calculating a distance L0 between a mark located on one side of the regular square and a mark located on an opposite side;
(4) a step of etching part or all of the metal layer of the test piece;
(5) a second measurement step of measuring the positions of the plurality of marks after etching and calculating a distance L1 between a mark located on one side of the square and a mark located on the opposite side; (6) calculating a difference L1-L0 between the distance L0 obtained in the first measurement step and the distance L1 obtained in the second measurement step for the same two marks before and after the etching;
The dimensional change after etching calculated from the value obtained by the test method including the following formula (b);
Dimensional change rate (%) = (L1−L0) / L0 × 100 (b)
May be ± 0.15% or less.

In the metal-clad laminate of the present invention, the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is derived from an aromatic tetracarboxylic acid residue and an aromatic diamine derived from an aromatic tetracarboxylic dianhydride. May contain an aromatic diamine residue.
In this case, the aromatic tetracarboxylic acid residue (PMDA residue) derived from pyromellitic dianhydride (PMDA) is added in an amount of 40 to 65 mol based on 100 mol parts of the total amount of the aromatic tetracarboxylic acid residue. And the aromatic tetracarboxylic acid residue (BPDA residue) derived from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and / or 1,4- An aromatic tetracarboxylic acid residue (TAHQ residue) derived from phenylene bis (trimellitic acid monoester) dianhydride (TAHQ) may be contained in a range of 25 to 60 mol parts in total.
Moreover, the aromatic diamine residue derived from the diamine compound represented by the following general formula (1A) and / or the general formula (1B) is added to the total amount of 100 mole parts of the aromatic diamine residue in total. 90 mole parts or more may be contained.

式（１Ａ）において、連結基Ｘは単結合又は−ＣＯＯ−を示し、Ｙは独立にフッ素原子で置換されていてもよい炭素数１〜３の１価の炭化水素もしくはアルコキシ基を示し、ｎは１〜２の整数を示し、ｐおよびｑは独立して０〜４の整数を示す。

In the formula (1A), the linking group X represents a single bond or —COO—, Y represents a monovalent hydrocarbon or alkoxy group having 1 to 3 carbon atoms which may be independently substituted with a fluorine atom, and n Represents an integer of 1 to 2, and p and q independently represent an integer of 0 to 4.

  In the metal-clad laminate of the present invention, the molar ratio of the PMDA residue contained in the non-thermoplastic polyimide to the total amount of the BPDA residue and the TAHQ residue [PMDA residue / (BPDA residue + TAHQ residue) )] May be in the range of 0.5 to 2.5.

  In the metal-clad laminate of the present invention, the polyimide layer may have a dielectric loss tangent (Df) at 10 GHz of 0.005 or less.

  The patterned metal-clad laminate of the present invention is obtained by patterning the metal layer of any of the above-described metal-clad laminates.

  Since the metal-clad laminate polyimide film of the present invention has a small dimensional change before and after etching and suppresses the occurrence of undulation of the polyimide layer, it is used in a process of manufacturing a circuit board material such as FPC or an electronic component. Useful as a member. By using the metal-clad laminate of the present invention, the reliability and yield of electronic components and electronic devices can be improved.

It is explanatory drawing of the target for position measurement used for measurement of the dimensional change rate after etching. It is explanatory drawing of the evaluation sample used for the measurement of the dimensional change rate after etching.

Next, an embodiment of the present invention will be described.
[Metal-clad laminate]
A metal-clad laminate according to one embodiment of the present invention includes a polyimide layer and a metal layer laminated on at least one surface of the polyimide layer. The metal-clad laminate of the present embodiment satisfies the following conditions (i) to (iii).

(I) The thickness of the polyimide layer is in the range of 1 to 15 μm.
When the thickness of the polyimide layer is within the above range, the effect of improving dimensional stability before and after etching is sufficiently exhibited. If the thickness of the polyimide layer is less than the above lower limit, problems may occur such that electrical insulation cannot be ensured, and handling becomes difficult in a manufacturing process due to reduced handling properties. On the other hand, when the thickness of the polyimide layer exceeds the above upper limit, the dimensional change before and after etching becomes large, and the undulation of the polyimide layer is apt to occur, which causes problems such as a decrease in productivity. The thickness of the polyimide layer is preferably, for example, in the range of 3 to 12 μm.

(Ii) The polyimide layer contains a non-thermoplastic polyimide layer, and the glass transition temperature Tg of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is 330 ° C. or lower.
The non-thermoplastic polyimide layer is the main layer in the polyimide layer. Here, the “main layer” means a layer having a thickness ratio of 60% or more with respect to the total thickness of the polyimide layer. By lowering the glass transition temperature (Tg) of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer, the residual stress when the polyamic acid is imidized by heat treatment on the metal layer to form the polyimide layer is reduced. It is thought that. In addition, “non-thermoplastic polyimide” generally refers to a polyimide that does not soften or exhibit adhesion even when heated, but in the present invention, it is measured using a dynamic viscoelasticity measuring device (DMA). It refers to a polyimide having a storage elastic modulus at 1.0 ° C. of 1.0 × 10 ⁹ Pa or more and a storage elastic modulus at 350 ° C. of 1.0 × 10 ⁸ Pa or more. The term “thermoplastic polyimide” generally refers to a polyimide whose glass transition temperature (Tg) can be clearly confirmed. In the present invention, the storage elastic modulus at 30 ° C. measured using DMA is 1.0%. X 10 ⁹ Pa or more, and refers to a polyimide having a storage elastic modulus at 350 ° C of less than 1.0 x 10 ⁸ Pa.

The residual stress of the polyimide layer accumulates due to the CTE difference between the polyimide layer and the metal layer when cooling from the maximum temperature T _{MAX of the} heat treatment to room temperature. However, it is considered that by lowering the glass transition temperature (Tg) of the non-thermoplastic polyimide constituting the main layer of the polyimide layer, the temperature range in which the residual stress is accumulated can be narrowed.
For example, if the maximum temperature T _MAX of the heat treatment is lower than the Tg of the non-thermoplastic polyimide, residual stress is accumulated in the polyimide layer in the entire temperature range of the cooling process from the maximum temperature T _MAX to room temperature after the heat treatment. On the other hand, when the Tg of the non-thermoplastic polyimide is designed to be lower than the maximum temperature T _{MAX of the} heat treatment, the CTE difference between the polyimide layer and the metal layer in the temperature range from T _MAX to Tg (that is, the temperature range exceeding Tg). The residual stress of the polyimide layer due to is hardly accumulated. That is, by designing the Tg of the non-thermoplastic polyimide to be lower than the maximum temperature T _{MAX of the} heat treatment, the temperature range in which the residual stress is easily accumulated is not the entire temperature range of the cooling process from the maximum temperature T _MAX to the room temperature, Since the temperature can be narrowed to a temperature range from Tg to room temperature, an increase in residual stress of the polyimide layer can be suppressed. Therefore, thermal expansion coefficient CTE _M of the metal layer is larger than the thermal expansion coefficient CTE _P of the polyimide layer, and, even if there is a certain difference between the two, it is possible to increase the dimensional stability before and after etching, the polyimide layer Undulation and slack are less likely to occur. From the above viewpoints, the glass transition temperature Tg of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is preferably 320 ° C. or lower. Incidentally, the maximum temperature T _MAX of the heat treatment of the polyamic acid was imidized to form the polyimide layer is a longitudinal generally 360 ° C..

  The Tg of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is preferably 280 ° C. or higher. When Tg is lower than 280 ° C., problems such as swelling of the resin layer and peeling off from the wiring are likely to occur when the FPC is manufactured.

(Iii) The coefficient of thermal expansion CTE _P of the polyimide layer and the coefficient of thermal expansion CTE _M of the metal layer satisfy the relationship of the following equation (a).
2 ppm / K ≦ CTE _M −CTE _P ≦ 8 ppm / K (a)
When the metal-clad laminate of the present embodiment is used for applications such as circuit board materials, it is preferable to minimize the CTE difference between the metal layer and the polyimide layer. It is less than the difference between _CTE M CTE _P is 2 ppm / K, the first place, since it is sufficiently high dimensional stability due to temperature changes, the condition (i), is little need to satisfy (ii). If the difference CTE _M CTE _P exceeds 8 ppm / K, the condition (i), it is filled with (ii), can not be sufficiently obtained effect of improving the dimensional stability before and after etching. Difference CTE _M CTE _P is, when satisfying the formula (a), to reduce the dimensional change before and after etching, the effect of suppressing the occurrence of undulation of the polyimide layer can be sufficiently exhibited.

Also, on condition that satisfies the relationship of formula (a), the metal-clad laminate of the present embodiment is preferably a thermal expansion coefficient CTE _P of the polyimide layer is less than 15 ppm / K, the thermal expansion of the metal layer it is preferable coefficient CTE _M is less than 20 ppm / K. Furthermore, on condition that satisfies the relationship of formula (a), the thermal expansion coefficient CTE _P of the polyimide layer is preferably in the range of -5~10ppm / K, the thermal expansion coefficient CTE _M of the metal layer, It is preferable to be within the range of 0 to 18 ppm / K. When the thermal expansion coefficient CTE _P coefficient of thermal expansion CTE _M and the polyimide layer of the metal layer outside the above range is not preferred because it affects the dimensional accuracy after patterning the wiring and the like.

The metal layer in the metal-clad laminate of the present embodiment, the thermal expansion coefficient CTE _M is not particularly limited in material as long as the, for example, copper, stainless steel, iron, nickel, beryllium, aluminum, zinc , Indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and alloys thereof. Among them, iron, nickel, stainless steel and alloys thereof are preferable from the viewpoint of low thermal expansion. The thickness of the metal layer is not particularly limited, but is preferably a thickness capable of suppressing breakage and deformation, preferably 100 μm or less, and more preferably 10 to 50 μm. From the viewpoints of production stability and handleability, the lower limit of the thickness of the metal layer is preferably 5 μm.

Further, it is preferable that the metal layer in the metal-clad laminate of the present embodiment satisfies the following relationships (A) and (A).
(A) the inflection point of the thermal expansion coefficient CTE _M of the metal layer is present to a temperature lower than the Tg of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer.
(A) The relationship of the following equation (c) is satisfied based on the temperature at the inflection point.
[CTE _{M in} the temperature range below the inflection point] <[CTE _M in the temperature higher than the inflection point] (c)

In a temperature range higher than the glass transition temperature (Tg) of the non-thermoplastic polyimide constituting the main layer of the polyimide layer, distortion due to the CTE difference between the polyimide layer and the metal layer is less likely to occur. Accordingly, the (A), when satisfying the relationship of (i) may be caused a significant increase in thermal expansion coefficient CTE _M of the metal layer if a higher temperature range than the inflection point, a non-thermoplastic polyimide layer Since the temperature range is higher than the glass transition temperature (Tg) of the constituent non-thermoplastic polyimide, distortion due to the CTE difference between the polyimide layer and the metal layer hardly occurs.
In addition, as a metal layer satisfying the above-mentioned relationship (A) and (A), for example, an invar foil can be mentioned. The invar foil has a CTE inflection point in a temperature region of, for example, 200 to 250 ° C., although it varies depending on the ratio of the contained iron element, nickel element, and trace element.

Further, in the metal-clad laminate of the present embodiment, the dimensional change after etching calculated by the following equation (b) is preferably ± 0.15% or less, and is ± 0.1% or less. Is more preferable. If the dimensional change after etching calculated by the equation (b) exceeds ± 0.15%, the reliability when processed into a circuit board such as an FPC, for example, is reduced.
Dimensional change rate (%) = (L1−L0) / L0 × 100 (b)

Here, L0 and L1 in the formula (b) are values obtained by a test method including the following steps (1) to (6).
(1) A step of preparing a test piece by cutting the metal-clad laminate to a predetermined length.
(2) When the longitudinal direction of the test piece is the MD direction and the lateral direction is the TD direction, for example, as shown in FIG. 1, a virtual positive side having sides parallel to the MD direction and the TD direction in the test piece. Assuming a square,
The four corners of the square and the four sides of the square in the MD and TD directions are linearly spaced at equal intervals based on the two corners forming the end of the one side. Forming a plurality of marks in an array.
(3) A first measurement step of measuring the positions of the plurality of marks and calculating a distance L0 between a mark located on one side of the regular square and a mark located on the opposite side.
(4) a step of etching part or all of the metal layer of the test piece;
(5) After the etching, as shown in FIG. 2, for example, the positions of the plurality of marks are measured, and a distance L1 between a mark located on one side of the square and a mark located on the opposite side is calculated. A second measurement step. (6) A step of calculating a difference L1-L0 between the distance L0 obtained in the first measurement step and the distance L1 obtained in the second measurement step for the same two marks before and after the etching.

  In the metal-clad laminate of the present embodiment, the dielectric loss tangent of the polyimide layer is 0.005 or less, preferably 0.001 or more when measured with a split post derivative resonator (SPDR) at a frequency of 10 GHz. 004 or less, more preferably 0.002 or more and 0.003 or less. When the metal-clad laminate of the present embodiment is applied, for example, as a material for a high-frequency circuit board, transmission loss can be reduced efficiently. In order to improve the dielectric characteristics of the circuit board, it is particularly important to control the dielectric loss tangent of the polyimide layer. By setting the dielectric loss tangent within the above range, the effect of reducing the transmission loss increases. Although the lower limit of the dielectric loss tangent of the polyimide layer at 10 GHz is not particularly limited, control of physical properties when the polyimide layer is applied as an insulating layer of a circuit board is taken into consideration. In addition, when the metal-clad laminate of the present embodiment is applied, for example, as a material for a circuit board, the dielectric constant at 10 GHz of the entire polyimide layer must be 4.0 or less in order to ensure impedance matching. Is preferred. If the dielectric constant of the polyimide layer at 10 GHz exceeds 4.0, when used for a circuit board such as an FPC, the dielectric loss of the polyimide layer is deteriorated, and inconvenience such as loss of an electric signal on a high-frequency signal transmission path is caused. May easily occur.

<Polyimide>
In the metal-clad laminate of the present embodiment, the polyimide constituting the polyimide layer is obtained by imidizing a polyamic acid obtained by reacting a tetracarboxylic dianhydride with a diamine compound. Therefore, the polyimide layer contains a tetracarboxylic acid residue and a diamine residue. In the present invention, the tetracarboxylic acid residue means a tetravalent group derived from tetracarboxylic dianhydride, and the diamine residue means a divalent group derived from a diamine compound. It represents that. In the metal-clad laminate of the present embodiment, the polyimide layer includes a non-thermoplastic polyimide layer, and may further include a thermoplastic polyimide layer.

(Non-thermoplastic polyimide)
The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer contains an aromatic tetracarboxylic acid residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine compound. .

<Acid anhydride>
Non-thermoplastic polyimides include aromatic tetracarboxylic acid residues derived from pyromellitic dianhydride (PMDA) and 3,3 ′, 4,4′-biphenyltetracarboxylic acid as the raw acid anhydride components. Aromatic tetracarboxylic acid residues (BPDA residues and / or TAHQ residues) derived from acid dianhydride (BPDA) and / or 1,4-phenylenebis (trimellitic acid monoester) dianhydride (TAHQ) ) Is preferable.
PMDA is because it has a rigid skeleton, in comparison to other common acid anhydride component, it is possible to suppress the thermal expansion coefficient CTE _P of the polyimide layer in-plane orientation of the control molecules in the polyimide, glass transition It is also effective in improving the temperature (Tg).
In addition, BPDA and / or TAHQ have a higher molecular weight than PMDA, and therefore have an effect of lowering the moisture absorption rate by lowering the imide group concentration by increasing the charge ratio. On the other hand, when the charge ratio of BPDA and / or TAHQ increases, the in-plane orientation of molecules in the polyimide decreases, leading to an increase in CTE.
From the above viewpoint, PMDA is preferably used in the range of 40 to 65 mol parts, more preferably in the range of 45 to 60 mol parts, based on 100 mol parts of the total acid anhydride component of the raw material. . If the amount of PMDA charged is less than 40 parts by mol with respect to 100 parts by mol of the total acid anhydride component of the raw material, the in-plane orientation of the molecule is reduced, making it difficult to reduce the CTE, and heating due to the decrease in Tg. The heat resistance and dimensional stability of the film at the time deteriorate. On the other hand, if the charged amount of PMDA exceeds 65 mol parts, Tg increases, and if there is a difference in CTE from the metal layer, dimensional stability decreases, and the moisture absorption rate deteriorates due to an increase in imide group concentration. I do.

  Further, BPDA and / or TAHQ are effective in lowering the moisture absorption due to a lower imide group concentration, but increase the CTE of the polyimide layer after imidization. From such a viewpoint, BPDA and / or TAHQ are preferably contained in a total amount of preferably 25 to 60 mol parts, more preferably 35 to 55 mol parts, based on 100 mol parts of the total acid anhydride component of the raw material. It is good to use within the range.

  As described above, in the metal-clad laminate of the present embodiment, the polyimide constituting the polyimide layer has a residue derived from PMDA of preferably 40 to 100 mol parts of the total amount of tetracarboxylic acid residues. Residues derived from BPDA and / or TAHQ in a range of 65 mole parts, more preferably in a range of 45-60 mole parts, preferably in a range of 25-60 mole parts, more preferably 35 It is preferable that the content is controlled so as to be within the range of about 55 mol parts.

  In addition, from the viewpoint of compatibility between CTE control and lowering of Tg, the molar ratio of PMDA residue contained in the non-thermoplastic polyimide to the total amount of BPDA residue and TAHQ residue [PMDA residue / (BPDA residue + TAHQ) Residue)] is preferably in the range of 0.5 to 2.5, more preferably 0.7 to 1.5.

  Examples of the tetracarboxylic dianhydride other than PMDA, BPDA, and TAHQ that can be used as a raw material for polyimide include, for example, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 4,4 ′ -Oxydiphthalic anhydride, 2,3 ', 3,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-, 2,3,3 ', 4'- or 3,3' , 4,4'-benzophenonetetracarboxylic dianhydride, 2,3 ', 3,4'-diphenylethertetracarboxylic 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-di (Ruboxyphenyl) sulfone 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-anthracenetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) tetrafluoro Propane dianhydride, 2,3,5,6-cyclohexane dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride Anhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4,5,8-) tetra Chloronaphthalene-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 dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4′-bis (2 Aromatic tetracarboxylic dianhydrides such as (3,3-dicarboxyphenoxy) diphenylmethane dianhydride.

<Diamine>
For the non-thermoplastic polyimide, it is preferable to use at least one aromatic diamine selected from the group consisting of aromatic diamines represented by the general formulas (1A) and (1B) as a raw material diamine component. An aromatic diamine represented by the general formula (1A) (hereinafter sometimes referred to as “diamine I”) and an aromatic diamine represented by the general formula (1B) (hereinafter sometimes referred to as “diamine II”) ) Can control the orientation of the molecules in the polyimide, suppress the increase in CTE, and reduce the moisture absorption. From such a viewpoint, the diamine I and / or the diamine II is preferably used in a total of 90 mol parts or more, for example, in a range of 90 to 100 mol parts with respect to 100 mol parts of all the diamine components of the raw material.

式（１Ａ）において、連結基Ｘは単結合又は−ＣＯＯ−を示し、Ｙは独立にフッ素原子で置換されていてもよい炭素数１〜３の１価の炭化水素もしくはアルコキシ基を示し、ｎは１〜２の整数を示し、ｐおよびｑは独立して０〜４の整数を示す。

In the formula (1A), the linking group X represents a single bond or —COO—, Y represents a monovalent hydrocarbon or alkoxy group having 1 to 3 carbon atoms which may be independently substituted with a fluorine atom, and n Represents an integer of 1 to 2, and p and q independently represent an integer of 0 to 4.

  Examples of the diamine I include 2,2′-dimethyl-4,4′-diaminobiphenyl (m-TB), 2,2′-n-propyl-4,4′-diaminobiphenyl (m-NPB), , 4 "-diamino-p-terphenyl, 2,2'-bis (trifluoromethyl) benzidine (TFMB), 4-aminophenyl-4'-aminobenzoate (APAB) and the like.

  Examples of the diamine II include, for example, 5-amino-2- (p-aminophenyl) benzoxazole (APBO), 6-amino-2- (p-aminophenyl) benzoxazole, and 5-amino-2- (m -Aminophenyl) benzoxazole, 6-amino-2- (m-aminophenyl) benzoxazole, and the like.

  As described above, the non-thermoplastic polyimide has a total of 90 mol parts or more, preferably 90 to 100 mol, of the residues derived from diamine I and / or diamine II based on 100 mol parts of the total amount of the diamine residues. It is better to control so as to be contained within the range of parts.

  Other diamines that can be used as a raw material of the non-thermoplastic polyimide include, for example, 2,6-diamino-3,5-diethyltoluene, 2,4-diamino-3,5-diethyltoluene, 2,4-diamino -3,3'-diethyl-5,5'-dimethyldiphenylmethane, 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene, 1,4-bis [2- (4-aminophenyl) ) -2-Propyl] benzene, 1,4 bis (4-aminophenoxy) -2,5-di-tert-butylbenzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 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] A Ter, bis [4- (3-aminophenoxy)] benzophenone, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 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-a (Minopentyl) 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-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5 -Aromatic diamine compounds such as -diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4,4'-diaminobenzanilide, and 4,4'-diaminobenzanilide Is mentioned.

  In the polyimide, the type of the tetracarboxylic acid and the diamine, and by selecting the respective molar ratio when applying two or more types of tetracarboxylic acids or diamines, the coefficient of thermal expansion when formed into a film, storage modulus, Tensile modulus, elongation, dielectric properties, etc. can be controlled. In addition, the structural unit of polyimide may exist as a block, or may exist at random.

  The weight average molecular weight of the polyimide is, for example, preferably in the range of 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 polyimide layer tends to decrease and the polyimide layer tends to become brittle. On the other hand, when the weight average molecular weight exceeds 400,000, the viscosity is excessively increased and defects such as unevenness in film thickness and streaks tend to occur during the coating operation.

<Filler>
In the metal-clad laminate of the present embodiment, the polyimide layer may contain an inorganic filler as needed. Specific examples of the inorganic filler include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and the like. These can be used alone or in combination of two or more.

  In general, a polyimide can be produced by reacting a tetracarboxylic dianhydride with a diamine compound in a solvent to produce a polyamic acid, and then heating and closing the ring. For example, a precursor of a polyimide is obtained by dissolving tetracarboxylic dianhydride and a diamine compound in an organic solvent in substantially equimolar amounts and stirring at a temperature within a range of 0 to 100 ° C. for 30 minutes to 24 hours to cause a polymerization reaction. Is obtained. In the reaction, the reaction components are dissolved so that the generated precursor is in the range of 5 to 30% by weight, preferably 10 to 20% by weight in the organic solvent. Examples of the organic solvent used for the polymerization reaction include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), -Butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, cresol and the like. Two or more of these solvents can be used in combination, and further, an aromatic hydrocarbon such as xylene or toluene can be used in combination. The amount of such an organic solvent used is not particularly limited, but is preferably adjusted so that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 30% by weight. Is preferred.

  Usually, the synthesized polyamic acid is advantageously used as a reaction solvent solution, but can be concentrated, diluted, or replaced with another organic solvent, if necessary. Polyamic acid is generally advantageously used because of its excellent solvent solubility. The viscosity of the polyamic acid solution is preferably in the range of 500 cps to 100,000 cps. If the thickness is out of this range, defects such as uneven thickness and streaks tend to occur in the film during coating work by a coater or the like. The method of imidizing the polyamic acid is not particularly limited. For example, a heat treatment in which the polyamide acid is heated in the solvent under a temperature condition in the range of 80 to 400 ° C. for 1 to 24 hours is suitably employed.

  As an embodiment of the method for manufacturing a metal-clad laminate of the present embodiment, for example, [1] a method in which a polyamic acid solution is applied to a metal foil, dried, and then imidized to form a polyimide layer (cast method); [2] A method of laminating a polyimide film on a metal foil (lamination method) is known, but a casting method is preferable. In the case where the polyimide layer is a multilayer composed of a plurality of polyimide layers, the production method may be, for example, [3] applying and drying a polyamic acid solution to a metal foil a plurality of times. And [4] a method in which polyamic acid is simultaneously laminated in a multilayer on a metal foil by multilayer extrusion by a multilayer extrusion, followed by drying and then imidization (hereinafter, multilayer extrusion method). . The method for applying the polyimide solution (or the polyamic acid solution) on the metal foil is not particularly limited, and for example, it can be applied with a coater such as a comma, a die, a knife, and a lip. In forming a multilayer polyimide layer, a method of applying a polyimide solution (or a polyamic acid solution) to a metal foil and drying the same is preferably repeated.

  In the casting method, since the polyamide acid resin layer is imidized in a state of being fixed to the metal foil, a change in expansion and contraction of the polyimide layer during the imidization process can be suppressed, and the thickness and dimensional accuracy can be maintained. When the polyimide layer is a multilayer including a plurality of polyimide layers, heat treatment for imidization is performed stepwise at a temperature in a range of, for example, 120 ° C. to 360 ° C., and the heat treatment time is 5 minutes or more. Preferably, by controlling the time within the range of 10 minutes to 20 minutes, foaming can be effectively suppressed, and problems such as swelling of the polyimide layer can be prevented.

  A preferred embodiment of the metal-clad laminate of the present embodiment is a copper-clad laminate. The copper-clad laminate only has to include a polyimide layer composed of a single layer or a plurality of layers, and a copper foil on at least one surface of the polyimide layer. Further, in order to increase the adhesiveness between the polyimide layer and the copper foil, the layer in contact with the copper foil in the polyimide layer may be a thermoplastic polyimide layer. The copper foil can be provided on one side or both sides of the insulating layer. That is, the copper-clad laminate of the present embodiment may be a single-sided copper-clad laminate (single-sided CCL) or a double-sided copper-clad laminate (double-sided CCL). The copper-clad laminate of the present embodiment can be used as an FPC, for example, by forming a copper wiring by processing a wiring circuit by etching a copper foil or the like.

[Patterned metal-clad laminate]
The metal-clad laminate of the present embodiment is useful mainly as a circuit board material such as an FPC or a member such as a mask used in a process of manufacturing an electronic component. That is, the metal layer of the metal-clad laminate of the present embodiment can be processed into a pattern by a conventional method to obtain a patterned metal-clad laminate. The patterned metal-clad laminate is, for example, a circuit board represented by FPC, an active element such as a transistor or a diode, or an electronic circuit including a passive device such as a resistor, a capacitor or an inductor. Sensor elements for sensing light, humidity, etc., light-emitting elements, image display elements such as liquid crystal display, electrophoretic display, and self-luminous display, wireless and wired communication elements, arithmetic elements, storage elements, MEMS elements, solar cells, thin-film transistors, etc. It can be used as

  As described above, the metal-clad laminate according to the present embodiment hardly causes a problem of dimensional change due to heating, and has high dimensional stability before and after etching, so that the reliability and the yield of a circuit board such as an FPC are improved. be able to.

  Examples will be shown below, and the features of the present invention will be described more specifically. However, the scope of the present invention is not limited to the examples. In the following examples, various measurements and evaluations are based on the following unless otherwise specified.

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

[Measurement of coefficient of linear thermal expansion (CTE _P ) in the surface direction of polyimide layer]
A polyimide film having a size of 3 mm × 15 mm is heated at a constant rate (10 ° C./min) and cooled at a constant rate (5 ° C.) while applying a load of 5.0 g with a thermomechanical analyzer (TMA: TMA / SS6100). / min) in a temperature range of 20 ° C. to 260 ° C. to carry out a tensile test. From the change in elongation with respect to the temperature change from 260 ° C. to 25 ° C., the coefficient of linear thermal expansion in the plane direction (ppm / K) Was measured.

[Measurement of linear thermal expansion coefficient (CTE _M ) in the surface direction of metal foil]
A metal foil having a size of 3 mm × 15 mm is heated at a constant rate (10 ° C./min) and cooled at a constant rate (5 ° C.) while applying a load of 5.0 g using a thermomechanical analyzer (TMA: TMA / SS6100). / min) in a temperature range of 20 ° C. to 360 ° C. to carry out a tensile test. / K) was measured.

[Measurement of glass transition temperature (Tg)]
The glass transition temperature of a polyimide film having a size of 5 mm × 20 mm was raised from 30 ° C. to 400 ° C. using a dynamic viscoelasticity measuring device (DMA: trade name; E4000F, manufactured by UBM Corporation). The measurement was performed at 4 ° C./min at a frequency of 11 Hz, and the temperature at which the change in elastic modulus (tan δ) became the maximum was defined as the glass transition temperature.

[Measurement of storage modulus]
The storage elastic modulus was measured using a dynamic viscoelasticity measuring device (DMA). A polyimide having a storage elastic modulus at 30 ° C. of 1.0 × 10 ⁹ Pa or more and a storage elastic modulus at 350 ° C. of 1.0 × 10 ⁸ Pa or more is referred to as “non-thermoplastic polyimide”. A polyimide having a modulus of 1.0 × 10 ⁹ Pa or more and a minimum storage elastic modulus at 350 ° C. of less than 1.0 × 10 ⁸ Pa is referred to as “thermoplastic polyimide”.

[Measurement of dimensional change after etching]
A metal-clad laminate having a size of 80 mm x 80 mm was prepared. After providing a dry film resist on the metal layer of this laminated board, it is exposed and developed to form 16 resist patterns each having a diameter of 1 mm as shown in FIG. Then, position measurement targets capable of measuring five points at 50 mm intervals in the vertical direction (MD) and the horizontal direction (TD) were prepared.
Regarding the prepared sample, the distance between the target in the vertical direction (MD) and the horizontal direction (TD) of the resist pattern on the target for position measurement was measured in an atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. After the measurement, the exposed portion of the metal layer at the opening of the resist pattern was removed by etching (etching solution temperature: 40 ° C. or less, etching time: within 10 minutes), and as shown in FIG. An evaluation sample having a residual point was prepared. This evaluation sample was allowed to stand for 24 ± 4 hours in an atmosphere having a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and then the distance between the metal layer residual points in the machine direction (MD) and the transverse direction (TD). Was measured. The dimensional change rates with respect to the normal state at each of the five positions in the vertical direction and the horizontal direction are calculated, and the average value of each is defined as the dimensional change rate after etching.
Each dimensional change rate was calculated by the following equation.
Dimensional change after etching (%) = (BA) / A × 100
A: distance between targets after resist development B: distance between metal layer residual points after metal layer etching

[Appearance evaluation]
After processing the metal foil on the metal-clad laminate with six metal wirings so as to have a metal wiring width of 1 mm and a space of 3 mm, the space between the wirings of the processed sample was visually checked. At this time, for the presence or absence of undulation of the polyimide layer, the distance between pitches of undulation was confirmed.

Abbreviations used in Examples and Comparative Examples indicate the following compounds.
PMDA: pyromellitic dianhydride NTCDA: 2,3,6,7-naphthalenetetracarboxylic dianhydride s-BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride TAHQ: 1, 4-phenylenebis (trimellitic acid monoester) dianhydride m-TB: 2,2'-dimethyl-4,4'-diaminobiphenylbisaniline-M: 1,3-bis [2- (4-aminophenyl) ) -2-Propyl] benzene APAB: 4-aminophenyl-4'-aminobenzoate APBO: 5-amino-2- (p-aminophenyl) benzoxazole DMAc: N, N-dimethylacetamide

(Synthesis example 1)
Under a nitrogen stream, 20.561 g of m-TB (0.0969 mol) and DMAc in an amount such that the solid content concentration after polymerization was 15% by weight were charged into the reaction vessel, and stirred at room temperature to dissolve. . Next, after adding 10.404 g of PMDA (0.0477 mol) and 14.035 g of s-BPDA (0.0477 mol), the polymerization reaction was carried out by continuing stirring at room temperature for 3 hours, and the polyamic acid solution 1 Was prepared. The solution viscosity of the polyamic acid solution 1 was 32,400 cps.

(Synthesis example 2)
Under a nitrogen stream, 20.898 g of m-TB (0.0984 mol) and DMAc in an amount such that the solid content concentration after polymerization was 15% by weight were charged into the reaction vessel, and stirred at room temperature to dissolve. . Next, after adding 12.690 g of PMDA (0.0582 mol) and 11.412 g of s-BPDA (0.0388 mol), the polymerization reaction was carried out by continuing stirring at room temperature for 3 hours, and the polyamic acid solution 2 Was prepared. The solution viscosity of the polyamic acid solution 2 was 34,100 cps.

(Synthesis example 3)
Under a nitrogen stream, 10.303 g of m-TB (0.0485 mol) and 10.932 g of APBO (0.0485 mol) and DMAc in an amount such that the solid content concentration after polymerization becomes 15% by weight were added to the reaction vessel under a nitrogen stream. And stirred at room temperature to dissolve. Next, after adding 12.513 g of PMDA (0.0574 mol) and 11.252 g of s-BPDA (0.0382 mol), the polymerization reaction was carried out by continuing stirring at room temperature for 3 hours, and the polyamic acid solution 3 Was prepared. The solution viscosity of the polyamic acid solution 3 was 18,400 cps.

(Synthesis example 4)
Under a nitrogen stream, 10.270 g of m-TB (0.0484 mol) and 11.042 g of APAB (0.0484 mol) and DMAc in an amount such that the solid content concentration after polymerization was 15% by weight were added to the reaction vessel. And stirred at room temperature to dissolve. Next, after adding 12.472 g of PMDA (0.0572 mol) and 11.216 g of s-BPDA (0.0381 mol), the polymerization reaction was carried out by continuing stirring at room temperature for 3 hours to obtain a polyamic acid solution 4 Was prepared. The solution viscosity of the polyamic acid solution 4 was 8,900 cps.

(Synthesis example 5)
Under a nitrogen stream, 18.309 g of m-TB (0.0862 mol) and DMAc in an amount such that the solid content concentration after polymerization was 15% by weight were added to the reaction vessel, and the mixture was stirred and dissolved at room temperature. . Next, after adding 11.118 g of PMDA (0.0510 mol) and 15.574 g of TAHQ (0.0340 mol), the polymerization reaction was carried out by continuing stirring at room temperature for 3 hours to prepare a polyamic acid solution 5. did. The solution viscosity of the polyamic acid solution 5 was 25,400 cps.

(Synthesis example 6)
Under a nitrogen stream, 18.3015 g of m-TB (0.0862 mol) and 1.563 g of bisaniline-M (0.0045 mol) and an amount that gives a solids concentration of 15% by weight after polymerization are introduced into the reaction vessel. Was added and stirred at room temperature to dissolve. Next, after adding 11.986 g of NTCDA (0.0447 mol) and 13.150 g of s-BPDA (0.0447 mol), the polymerization reaction was carried out by continuing stirring at room temperature for 3 hours to obtain a polyamic acid solution 6 Was prepared. The solution viscosity of the polyamic acid solution 6 was 37,700 cps.

[Example 1]
The polyamic acid solution 1 was uniformly applied to one side of a 12 μm-thick electrolytic copper foil so as to have a cured thickness of about 12 μm, and then heated and dried at 120 ° C. to remove the solvent. Further, a stepwise heat treatment from 120 ° C. to 360 ° C. was performed within 60 minutes to complete imidization, and a metal-clad laminate 1 was prepared.
About the obtained metal-clad laminate 1, the dimensional change after etching was evaluated. As a result, it was 0.06%. Further, as a result of measuring the thermal expansion coefficient CTE _M of the used electrolytic copper foil for the metal-clad laminate 1, the CTE _M was 17.1 ppm / K, and the thermal expansion coefficient of the polyimide film 1 after the electrolytic copper foil etching was measured. coefficient CTE _P is 14.5 ppm / K, Tg is 312 ° C., showed non-thermoplastic. Furthermore, when the external appearance after the metal wiring processing was confirmed, undulations with a period of 4 mm were confirmed.

[Examples 2 to 10, Comparative Examples 1 to 3]
The metal-clad laminates 2 to 13 shown in Tables 1 and 2 were prepared in the same manner as in Example 1, the dimensional change after etching, the coefficient of thermal expansion CTE _{M of} the metal foil used, and the polyimide film after metal foil etching. Was evaluated for thermal expansion coefficient CTE _P and appearance after metal wiring processing. At this time, the type of the metal foil and the polyamic acid, the heat treatment temperature and the heat treatment time were changed. The evaluation results are shown in Tables 1 and 2.

Although the embodiments of the present invention have been described in detail for the purpose of illustration, the present invention is not limited to the above embodiments, and various modifications are possible.

Claims (7)

A metal-clad laminate including a polyimide layer and a metal layer laminated on at least one surface of the polyimide layer, wherein the following conditions (i) to (iii);
(I) the thickness of the polyimide layer is in the range of 1 to 15 μm;
(Ii) the polyimide layer includes a non-thermoplastic polyimide layer, and the glass transition temperature Tg of the non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer is 330 ° C. or less;
(Iii) The coefficient of thermal expansion CTE _P of the polyimide layer and the coefficient of thermal expansion CTE _M of the metal layer have a relationship represented by the following equation (a):
2 ppm / K ≦ CTE _M −CTE _P ≦ 8 ppm / K (a)
A metal-clad laminate characterized by satisfying the following. The thermal expansion coefficient CTE _P of the polyimide layer is less than 15 ppm / K, metal-clad laminate according to claim 1 thermal expansion coefficient CTE _M of the metal layer is less than 20 ppm / K. The following steps (1) to (6);
(1) a step of preparing a test piece by cutting the metal-clad laminate to a predetermined length;
(2) Assuming that the vertical direction of the test piece is the MD direction and the horizontal direction is the TD direction, a virtual square having sides parallel to the MD direction and the TD direction in the test piece is assumed;
The four corners of the square and the four sides of the square in the MD and TD directions are linearly spaced at equal intervals based on the two corners forming the end of the one side. Forming a plurality of marks in an array,
(3) a first measurement step of measuring positions of the plurality of marks and calculating a distance L0 between a mark located on one side of the regular square and a mark located on an opposite side;
(4) a step of etching part or all of the metal layer of the test piece;
(5) a second measurement step of measuring the positions of the plurality of marks after etching and calculating a distance L1 between a mark located on one side of the square and a mark located on the opposite side; (6) calculating a difference L1-L0 between the distance L0 obtained in the first measurement step and the distance L1 obtained in the second measurement step for the same two marks before and after the etching;
From the value obtained by the test method including
Dimensional change after etching calculated by the following equation (b):
Dimensional change rate (%) = (L1−L0) / L0 × 100 (b)
The metal-clad laminate according to claim 1 or 2, wherein the value is ± 0.15% or less. The non-thermoplastic polyimide constituting the non-thermoplastic polyimide layer includes an aromatic dicarboxylic acid residue derived from an aromatic tetracarboxylic dianhydride and an aromatic diamine residue derived from an aromatic diamine. And
For the total amount of 100 mole parts of the aromatic tetracarboxylic acid residue,
An aromatic tetracarboxylic acid residue (PMDA residue) derived from pyromellitic dianhydride (PMDA) is in the range of 40 to 65 mol parts, and
Aromatic tetracarboxylic acid residues (BPDA residues) derived from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and / or 1,4-phenylenebis (trimellitic acid Ester) containing an aromatic tetracarboxylic acid residue (TAHQ residue) derived from dianhydride (TAHQ) in a range of 25 to 60 mol parts in total,
A total of 90 moles of the aromatic diamine residue derived from the diamine compound represented by the following general formula (1A) and / or the general formula (1B) is based on 100 mole parts of the total amount of the aromatic diamine residue. The metal-clad laminate according to any one of claims 1 to 3, wherein the metal-clad laminate contains at least one part by weight.

[In the formula (1A), the linking group X represents a single bond or -COO-, Y represents a monovalent hydrocarbon or alkoxy group having 1 to 3 carbon atoms which may be independently substituted with a fluorine atom, n shows the integer of 1-2, p and q show the integer of 0-4 independently. ]   The molar ratio [PMDA residue / (BPDA residue + TAHQ residue)] of the PMDA residue contained in the non-thermoplastic polyimide to the total amount of the BPDA residue and the TAHQ residue is 0.5 to 2. The metal-clad laminate according to claim 4, wherein the thickness is within the range of 5.   The metal-clad laminate according to any one of claims 1 to 5, wherein the polyimide layer has a dielectric loss tangent (Df) at 10 GHz of 0.005 or less. A patterned metal-clad laminate, wherein the metal layer of the metal-clad laminate according to claim 1 is patterned.

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