JP2001315256A - Flexible metal foil-clad laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible metal foil-clad laminate suitably used as a hard disc suspension board having excellent flexibility and solder heat resistance or a future novel high density mounting application material such as an FPC, a rigid flexible board material, a COF and LOC package, an MCM or the like. SOLUTION: The flexible metal foil-clad laminate comprises at least one type of metal foil, a thermoplastic polyimide layer and a heat resistant base film. In this case, the polyimide layer is made of a thermoplastic polyimide having a glass transition temperature of 150 to 300 deg.C and a water absorption ratio of 1% or less and/or the base film is made of a non-thermoplastic polyimide film having a water absorption ratio of 2% or less or a thermoplastic polyimide film having a glass transition temperature of 350 deg.C or higher and a water absorption ratio of 2% or less. Thus, the laminate has good flexibility and heat resistance. Particularly, the flexible metal foil-clad laminate for a hard disc suspension is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible metal foil-clad laminate that can be used as an electric wiring board material. More specifically, in a solder bath dip test (280 ° C. for 10 seconds) after a moisture absorption treatment at 40 ° C./90%/96 hours, there is no abnormal appearance, that is, excellent heat resistance such that no swelling or peeling between layers occurs. More particularly, the present invention relates to a flexible metal foil-clad laminate used for a hard disk drive suspension.

[0002]

2. Description of the Related Art Flexible electronic circuit boards (hereinafter, referred to as FPCs) have been rapidly advancing as electronic devices have become more sophisticated, functional and smaller.
The demand for flexible metal foil-clad laminates, which is a material of the above, has been expanding more and more, and the market requirements for various physical properties such as heat resistance, mechanical strength, and electrical properties have been further enhanced.

As a flexible metal foil-clad laminate having good heat resistance, a laminate using polyimide as a base film has been conventionally used. However, an epoxy resin or an acrylic resin is used to bond the metal foil to the polyimide film. Since an adhesive having lower heat resistance was used as compared with polyimide such as a system, it could not be said that the heat resistance of the polyimide film was fully utilized. To solve this problem, the base film and the adhesive are also polyimide,
A so-called all-polyimide metal foil-clad laminate has been developed.

[0004] One of the all-polyimide metal foil-clad laminates that has recently attracted attention is a two-layer type laminate having no adhesive layer. And a method of forming a polyimide layer directly on a metal foil are known.

However, in the method of forming a conductor layer directly on a polyimide film, a thin layer of a metal conductor is first formed by a vapor deposition method or a sputtering method, and then a thick layer of a metal conductor is formed by a plating method. There are problems that pinholes are easily generated during formation and that sufficient adhesion between the insulating layer and the metal conductor layer cannot be obtained.

On the other hand, in the method of forming a polyimide layer directly on a metal foil, a method of casting and drying a solution of a polyimide or a solution of a polyamic acid on a metal foil and forming the polyimide layer is employed. However, depending on the solvent used for casting, corrosion of the conductor layer is likely to occur, and when preparing a double-sided board, it is necessary to make two single-sided boards and then to peel off these single-sided boards, which is complicated. There was a problem that required a process.

As an all-polyimide metal-foil-clad laminate that solves the above-mentioned problems, a laminate in which a base polyimide film and a metal foil are adhered to each other via a thermoplastic polyimide having a heat-fusing property is disclosed in Japanese Unexamined Patent Publication No. Hei. 138789
JP-A-5-279224, JP-A-5-22376
No. 8 is proposed.

Meanwhile, among printed wiring boards, a suspension wiring board for a magnetic head of a hard disk drive or the like is used to balance the air levitation force received with the rotation of the disk and the rigid reaction force of the printed wiring board so that the magnetic flux can be reduced as much as possible. In order to bring the head close to the disk, it is more convenient to pattern the wiring from the head directly onto a microminiature support spring made of stainless steel, and a substrate manufactured by the above method is suitably used.

[0009]

However, in recent years, with the miniaturization of the equipment, the precision of the substrate for the hard disk has been required and the heat resistance has been required. Therefore, the suspension for the magnetic head of the hard disk drive has been required. It has been pointed out that a problem arises in the wiring substrate for use that the substrate is warped by various external forces during the operation of the suspension.

In order to solve such a problem, it has been desired to employ an insulating material having good flexibility as a hard disk suspension wiring board. However, a material that has both heat resistance and good flexibility has not been known in the world.

[0011]

Means for Solving the Problems The present inventors have developed a metal foil-clad laminate using the above-mentioned thermoplastic polyimide having heat-fusibility as an adhesive layer, a material showing flexibility and good heat resistance, In particular, the inventors of the present invention have made intensive studies for the purpose of providing a material that can be suitably used for an all-polyimide hard disk suspension, and as a result, have arrived at the present invention.

That is, a flexible metal foil-clad laminate according to the present invention is a flexible metal foil-clad laminate comprising at least one or more metal foils, a thermoplastic polyimide layer and a heat-resistant base film. The layer has a glass transition temperature of 150 ° C or more and 300 ° C or less and 1
% Of a thermoplastic polyimide film having a water absorption of not more than 2%, and / or a heat-resistant base film having a water absorption of not more than 2%.
Thermoplastic polyimide films having both a glass transition temperature of not less than ° C. and a water absorption of not more than 2% are used. Thus, the present invention can realize a flexible metal foil-clad laminate having both good flexibility and heat resistance, particularly a flexible metal foil-clad laminate for a hard disk drive suspension.

[0013]

Embodiments of the present invention will be described below. The flexible laminate of the present invention is obtained by laminating at least one or more thin metal foils, a thermoplastic adhesive layer, and a heat-resistant base film.

The resin layer forming the insulating layer, that is, the thermoplastic adhesive layer and the heat-resistant base film are not particularly limited as long as those skilled in the art can generally assume this application. In particular, a polyimide-based resin is suitably used, and it is preferable to use this as a main component. Further, a polyimide resin having a tensile elongation of 20% or more has desirable flexibility as a flexible metal foil-clad laminate for a hard disk drive suspension, and is therefore desirable.

Further, the thermoplastic polyimide constituting the thermoplastic adhesive layer used in the flexible gold pot foil-clad laminate of the present invention has a repeating unit of polyamic acid, which is a precursor thereof, represented by the following general formula (2):

[0016]

Embedded image

(Wherein, R ₁ represents a tetravalent organic group and R ₂ represents a divalent organic group). The precursor polyamic acid of a thermoplastic polyimide which can be preferably used is represented by the following general formula ( 1) Chemical 5,

[0018]

Embedded image

(Where k is an integer of 1 or more, and m and n are
m + n is an integer of 0 or more, each of which is 1 or more.
A and B may be the same or different 4
X and Y each represent a divalent organic group which may be the same or different. ) Can be obtained by dehydration and ring closure of the polyamic acid copolymer represented by the formula (1).

The polyamic acid copolymer is represented by the following general formula (3):

[0021]

Embedded image

The general formula (4),

[0023]

Embedded image

An acid dianhydride compound represented by the following general formula (5) and H ₂ N—X—NH ₂ general formula (5) The following general formula (6) H ₂ NY—NH ₂ general It is obtained by reacting a diamine compound represented by the formula (6) in an organic solvent.
The tetravalent organic group A in the formula (4) and the tetravalent organic group B in the formula (4) are represented by the following group (I) 8,

[0025]

Embedded image

It is preferably a tetravalent organic group selected from

The divalent organic group X in the general formula (5) and the divalent organic group Y in the general formula (6) are represented by the following group (II):
Chemical formula 9,

[0028]

Embedded image

It is preferably a divalent organic group selected from the group consisting of:

Known procedures can be applied to the procedure of the polyamic acid polymerization reaction. One embodiment will be described below. In an atmosphere of an inert gas such as argon or nitrogen, the acid dianhydride compound of the general formula (3) is dissolved or diffused in an organic solvent, and the diamine compound represented by the general formula (5) and the general formula (6) ) Is added in a solid state or an organic solvent solution state. Further, a mixture of the acid dianhydride compound represented by the general formula (3) and the acid dianhydride compound represented by the general formula (4) is added in a solid state or an organic solvent solution, and the polyamic acid copolymer is added. Obtain a polymer solution. In this reaction, contrary to the above-described addition procedure, first, a solution of a diamine compound is prepared, and a solid acid dianhydride compound or an organic solvent solution of an acid dianhydride compound is added to the solution. Good. The reaction temperature at this time is preferably from -10C to 0C. The reaction time is 30 minutes to 3 hours. By this reaction, a polyamic acid solution which is a precursor of the thermoplastic polyimide is prepared.

The ratio of the total molar amount of the acid dianhydride to the total molar amount of the diamine is preferably substantially equimolar.

Examples of the organic solvent used in the synthesis reaction of the polyamic acid include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide; formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide; N-dimethylacetamide,
Acetamide solvents such as N, N-diethylacetamide can be mentioned. These may be used alone or in combination of two or more. Further, a mixed solvent composed of these polar solvents and a non-solvent of polyamic acid can also be used. Non-solvents for polyamic acid include acetone, methanol,
Ethanol, isopropanol, benzene, methyl cellosolve and the like can be mentioned.

The molecular weight of the thermoplastic polyimide and the polyamic acid as a precursor thereof are not particularly limited. However, in order to maintain the strength as a heat-resistant adhesive, the number average molecular weight is 50,000 or more, and 80,000 or more, especially 10
10,000 or more is preferable. The molecular weight can be measured by GPC (gel permeation chromatography). If the average molecular weight is less than 50,000, the resulting film becomes brittle,
On the other hand, if it exceeds 100,000, the viscosity of the polyamic acid varnish becomes too high, and handling becomes difficult, which is not preferable.

Next, a method for obtaining polyimide from these polyamic acids will be described. Examples of the method for imidizing the polyamic acid include a method for dehydration ring closure (imidization) by a thermal method or a chemical method.

The method of dehydration ring closure (imidization) by a thermal method includes a method by heating under normal pressure and a method by heating under reduced pressure. When heating under normal pressure,
For example, it is preferable to perform heating at a temperature of 150 ° C. or less for about 5 minutes to 90 minutes to evaporate the organic solvent.
Subsequently, it is preferably imidized by heating in a temperature range of 150 to 400 ° C. The heating temperature in the final stage of imidization is preferably 300 to 400 ° C. On the other hand, when heating is performed under reduced pressure, solvent removal and imidization proceed simultaneously.
The heating temperature is preferably in the range of 150C to 200C. Heating under reduced pressure is more advantageous than normal pressure heating in that hydrolysis of the imide ring and accompanying molecular weight reduction are less likely to occur than in normal pressure heating, since water is easily removed from the system.

Dehydration ring closure (imidization) by a chemical method
In the method, a dehydrating agent having a stoichiometric amount or more and a catalytic amount of a tertiary amine are added to the polyamic acid solution, and the resultant is treated in the same manner as in the case of dehydration ring closure by a thermal method. The desired polyimide can be obtained in time. Tertiary amines used as catalysts include pyridine, α-
Picoline, β-picoline, γ-picoline, trimethylamine, triethylamine, isoquinoline and the like are preferable, and an aliphatic acid anhydride such as acetic anhydride is used as a dehydrating agent.

The polyimide resin produced by the above method has a high preservability by evaporating the organic solvent.
It can also be obtained as a solid. The polyimide resin used for the adhesive layer of the flexible metal foil-clad laminate of the present invention obtained as a solid is dissolved in an organic solvent and laminated on a base film.

Examples of the organic solvent for dissolving the polyimide resin obtained above include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, and N, N-diethylformamide. Acetamide solvents such as N-dimethylacetamide and N, N-diethylacetamide; pyrrolidone solvents such as N-methyl-2-pyrrolidone; ether solvents such as tetrahydrofuran, 1,4-dioxane and dioxolane can be mentioned. These may be used alone or in combination of two or more. In these organic solvents, the polyimide resin is preferably dissolved in an amount of 5 to 40% by weight, preferably 10 to 30% by weight, from the viewpoint of handling, but is not limited thereto. By the above procedure, a solution of the thermoplastic polyimide constituting the thermoplastic polyimide layer which is the thermoplastic adhesive layer of the metal foil clad laminate of the present invention is obtained.

Alternatively, the polyimide resin can be applied to a base film as an adhesive layer in a varnish state dissolved in a reaction solution. Further, in the state of a polyamic acid solution, it can be applied to a base film, dried by heating, and imidized.

The thermoplastic polyimide used for the adhesive layer of the present invention obtained as described above has a glass transition temperature of 150 ° C. or more and 300 ° C. or less, and a water absorption value of 1% or less. When a thermoplastic polyimide having such properties is used for the thermoplastic adhesive layer of a flexible metal foil-clad laminate, it exhibits high solder heat resistance even after moisture absorption.
A metal foil-clad laminate having characteristics in which appearance abnormality does not occur even in a solder dip test after a moisture absorption treatment at 0 ° C./90%/96 hours can be obtained.

Next, the heat-resistant base film used for the metal foil-clad laminate of the present invention will be described. As the heat-resistant base film used in the present invention, a polyimide film, polyamide imide, polybenzimidazole,
A heat-resistant base film made of polybenzoxazole, polyphenylene sulfide, polyetheretherketone, polyethersulfone, polyetherimide, or the like can be preferably used, but a polyimide film is particularly preferable. As the polyimide film, a non-thermoplastic polyimide typified by a polyimide obtained from pyromellitic dianhydride and 4,4′-diaminodiphenyl ether is preferable. In particular, a polyimide resin having a water absorption of 2% or less is preferably used. It is desirable to use a metal foil-clad laminate that exhibits high solder heat resistance even after the moisture absorption treatment and does not cause abnormal appearance even in a solder dip test after the moisture absorption treatment at 40 ° C./90%/96 hours. Further, a thermoplastic polyimide film having a glass transition temperature of 350 ° C. or higher can also be preferably used as the heat-resistant base film. A polyimide film having such characteristics is, for example, a polyimide film brand name Apical HP
(Kanebuchi Chemical Industry Co., Ltd.) is used.

Next, the above-mentioned thermoplastic polyimide solution is applied to the heat-resistant base film to form a thermoplastic polyimide layer. Alternatively, a method in which a polyamic acid, which is a precursor of a thermoplastic polyimide, is applied to a heat-resistant base film and converted into polyimide by a thermal or chemical method on the base film to form a thermoplastic polyimide layer may be employed.

The heat-resistant base film having the thermoplastic polyimide layer formed thereon and the metal foil are laminated under pressure under heating to complete the metal foil-clad laminate of the present invention. Examples of the laminating method include a multi-stage press machine using a batch system, and a continuous system using a double belt press machine or a hot roll press laminating machine.From the viewpoint of productivity and equipment costs, the hot roll press method is used. A continuous production method is preferable, and productivity can be further improved by laminating in multiple stages.

The thin metal foil used for the metal foil laminated substrate is not particularly limited, but SUS foil, copper alloy foil, aluminum foil and the like can be used.

Further, the flexible metal foil-clad laminate according to the present invention is a flexible substrate requiring flexibility.
In particular, since the heat-resistant base film is used for a flexible metal foil-clad laminate for a hard disk suspension, the thickness of the heat-resistant base film is 5 μm or more and 20 μm or less, particularly 5 μm or less.
The thickness of the thermoplastic adhesive layer is preferably 5 μm or more and 20 μm or less, and particularly preferably 5 μm or more and 10 μm or less. Further, the thickness of the metal foil is preferably 5 μm or more and 18 μm or less, and particularly preferably 5 μm or more and 18 μm or less.

The flexible metal foil-clad laminate of the present invention obtained as described above has a
Using a thermoplastic polyimide having a glass transition temperature of not more than 1 ° C. and a water absorption of not more than 1% as a thermoplastic polyimide layer,
In addition, a non-thermoplastic polyimide film having a water absorption of 2% or less as a heat-resistant base film, or a thermoplastic polyimide film having a glass transition temperature of 350 ° C. or more and a water absorption of 2% or less is used.

Accordingly, it is possible to obtain a flexible metal foil-clad laminate having both good flexibility and heat resistance and excellent solder heat resistance. Further, a metal foil having a predetermined thickness and a base can be obtained. Especially in combination with film,
It is useful as a flexible metal foil-clad laminate suitable for hard disk drive suspension.

Although the embodiments of the flexible metal foil-clad laminate according to the present invention have been described above, the present invention is not limited to these, and based on the knowledge of those skilled in the art without departing from the spirit thereof. It can be implemented with improvements, changes, and modifications.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flexible metal foil-clad laminate for a hard disk drive suspension according to the present invention will be described in detail below.

The adhesive strength (kgf / cm) is measured according to JIS C
6481.

According to JIS C 6471, the solder heat resistance is 280 ° C. after adjusting at 40 ° C., 90% RH and 96 hours.
The measurement was performed under the condition of immersion for 10 seconds, and the presence or absence of abnormalities of the whitening phenomenon and the peeling phenomenon on the appearance was determined.

The glass transition temperature (Tg) of the thermoplastic polyimide layer was determined by using the above-obtained thermoplastic polyimide solution as follows:
A sample processed into a 25 μm thermoplastic polyimide simple film obtained by casting and drying was measured by a viscoelasticity measuring device.

The water absorption was calculated by measurement based on ASTM D570. The above-mentioned 25 μm film of the thermoplastic polyimide alone was further dried at 150 ° C. for 30 minutes, and the weight of the film was W1. Under a 20 ° C. environment, the film was immersed in distilled water for 24 hours. The weight increase rate was calculated by the equation. Water absorption (%) = (W2−W1) ÷ W1 × 100

The flex resistance evaluation test (MIT)
Mitutoyo MIT tester (manufactured by Mitutoyo Corporation) equipped with a bending jig of R = 0.38 based on IS C5016
The number of times until the CCL was broken was measured.

[0055]

Example 1 The whole system was cooled with ice water and purged with nitrogen.
In a 000 ml three-neck separable flask, 123.1 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (hereinafter referred to as BAPP) was 716.2 g.
g of dimethylformamide (hereinafter referred to as DMF) and stirred for 15 minutes. Then 67.7g of 3,3
', 4,4'-Benzophenonetetracarboxylic dianhydride (hereinafter referred to as BTDA) and 20 g of DMF were added. Then, 33.9 g of 3,3 ', 4,4'
-Ethylene glycol dibenzoate tetracarboxylic dianhydride (hereinafter referred to as TMEG) in 20 g of DMF
And stirred for 30 minutes. After stirring for 30 minutes, a solution in which 4.1 g of TMEG was dissolved in 36.9 g of DMF was gradually added while paying attention to the viscosity of the solution in the flask. A polyamic acid solution having a concentration of 23% by weight was obtained.

The obtained thermoplastic polyimide was separately formed into a film having a thickness of 25 μm for a sample, and the glass transition temperature (Tg) and the water absorption were measured. Table 1 shows the results.

The resulting polyamic acid solution was coated on both sides of a polyimide film (Apical 12.5HP; manufactured by Kaneka Chemical Co., Ltd., water absorption: 1.4%) to a final thickness of one side of a thermoplastic polyimide layer of 6 μm. After application, 1
The solvent was removed by heating at 40 ° C. and 220 ° C. for 2 minutes each to form a thermoplastic polyimide layer. The water absorption of this product is
0.8%. A 18 μm-thick rolled copper foil was overlaid on both sides of this, and a 25 μm-thick polyimide film was provided thereon as a release film, and laminated with a double belt press to obtain a flexible copper-clad laminate. The lamination temperature was 280 ° C., the pressure was 70 kgf / cm 2, and the lamination time was about 5 minutes.

With respect to the obtained copper-clad laminate, the adhesive strength (kgf / cm) and the solder heat resistance were measured. Further, a bending resistance evaluation test (MIT) was performed. Table 1 shows the results.

[0059]

Example 2 Example 1 was repeated except that 88.2 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter referred to as BPDA) was used in place of BTDA and TMEG in Example 1. A flexible copper-clad laminate was produced in the same manner as described above. Table 1 shows the results.

[0060]

Example 3 A flexible copper-clad laminate was produced in the same manner as in Example 1, except that 65.1 g of oxyphthalic dianhydride (hereinafter referred to as ODPA) was used instead of BTDA of Example 1. Table 1 shows the results.

[0061]

Comparative Example 1 Apical 12.5NPI was used in place of Apical 12.5HP of Example 1, and Pixio D was used as an adhesive.
A flexible copper-clad laminate was prepared in the same manner as in Example 1 except that varnish (manufactured by Kanegafuchi Chemical Co., Ltd., Tg 140 ° C, water absorption 0.4%) was used. Table 1 shows the results.

[0062]

Comparative Example 2 A flexible copper-clad laminate was produced in the same manner as in Example 1 except that a thermoplastic polyimide synthesized from BTDA and benzophenonediamine was used as an adhesive. Table 1 shows the results.

[0063]

[Table 1]

[0064]

As described above, the flexible metal foil-clad laminate of the present invention can be used as a substrate when a laminate is obtained by combining a base film having characteristics of water absorption and glass transition temperature and a thermoplastic adhesive layer. No warpage, excellent flexibility and solder heat resistance, and as a substrate for hard disk suspension, and on the other hand, as a new high-density packaging material for FPC, rigid-flex substrate, COF and LOC packages, MCM, etc. Is also preferably used.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 1/03 610 H05K 1/03 610N 670 670Z // C08L 79:08 C08L 79:08 F term (reference) 4F071 AA60 AA86 AF10Y AF21Y AF26 AH12 BA02 BB02 BC01 BC02 4F100 AB01A AB04A AB10A AB31A AB33A AK49B AT00B BA02 GB43 JJ03 JJ03B JK06 JK17 4J043 PA04 QB31 UA121 UA122 UA131 UA132 UA141 UA151 UA152 UB011 UB021 UB022 UB051 UB052 UB121 UB122 UB131 UB132 UB152 UB172 UB301 UB302 VA011 VA021 VA031 VA041 VA042 VA061 VA062 VA081 XA13 XA15 XA16 ZA02 ZA05 ZA33 ZA34 ZB01 ZB47 5D068 AA01 BB01 CC01 EE19 GG03

Claims (10)

[Claims] 1. A flexible metal foil-clad laminate comprising at least one or more thin metal foils, a thermoplastic adhesive layer, and a heat-resistant base film, wherein the thermoplastic adhesive layer and the heat-resistant base film are mainly composed of Is a polyimide resin having a tensile elongation of 20% or more, and the thermoplastic adhesive layer is a thermoplastic polyimide resin having a glass transition temperature of 150 ° C. or more and 300 ° C. or less and a water absorption of 1% or less. Composed, flexible metal foil clad laminate. 2. The thermoplastic polyimide resin is represented by the following general formula (1): (In the formula, k is an integer of 1 or more, and m and n are each an integer of 0 or more where m + n is 1 or more. A and B may be the same or different and each may be a tetravalent organic compound. Group,
X and Y may be the same or different 2
It shows a valent organic group. The flexible metal foil-clad laminate according to claim 1, comprising a thermoplastic polyimide obtained by dehydrating and ring-closing the polyamic acid represented by the formula (1). 3. A and B in the general formula (1) are represented by the following group (I): Is at least one tetravalent organic group selected from
The flexible metal foil-clad laminate according to claim 2. 4. X and Y in the general formula (1) are represented by the following group (II): 4. A divalent organic group selected from the group consisting of:
The flexible metal foil-clad laminate according to the above. 5. The non-thermoplastic polyimide film having a water absorption of 2% or less, wherein
The flexible metal foil-clad laminate according to any one of claims 1 to 4, which is a thermoplastic polyimide film having a glass transition temperature of 50 ° C or more and a water absorption of 2% or less. 6. The flexible metal foil-clad laminate according to claim 1, wherein the metal foil is selected from one of a copper alloy foil, a SUS foil, and an aluminum foil. 7. The solder bath dip test (280 ° C. for 10 seconds) after a moisture absorption treatment at 40 ° C./90%/96 hours does not cause any abnormal appearance. The flexible metal foil-clad laminate according to the above. 8. A flexible metal foil-clad laminate for a hard disk drive suspension, using the flexible metal foil-clad laminate according to claim 1. Description: 9. The flexible metal foil-clad laminate for a hard disk drive suspension according to claim 7, wherein the heat-resistant base film is a thin film having a thickness of 5 μm or more and 20 μm or less. 10. The metal foil according to claim 8, wherein the metal foil is a thin metal foil having a thickness of 5 μm or more and 18 μm or less.
The flexible metal foil-clad laminate for a hard disk drive suspension described in the above item.