JP2007272941A - Method of manufacturing laminate for hdd suspension - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a laminate for an HDD suspension which can meet the demand of ultrathinning of the laminate, can be subjected to fine wiring and is free from appearance defects by suppressing wrinkles or curls and is excellent in adhesiveness between a resin layer and an ultrathin copper foil. <P>SOLUTION: The method for manufacturing the laminate for the HDD suspension the ultrathin copper foil as a conductor body, is characterized in that after a multilayer polyimide resin layer having a polyimide resin layer (A) on its surface is formed on the ultrathin copper foil which couples a support metal layer via a delamination layer by the coating/drying polyimide or precursor resin solution repeatedly, the polyimide resin layer is subjected to imidization, and heated to temperature equal to a glass transition temperature or higher of the polyimide resin layer (A) via the polyimide resin layer (A), and the resin layer is thermocompressed with a stainless steel sheet under pressure. Then, it is cooled down to the glass transition temperature of the polyimide resin layer (A) or cooler and the support metal layer is delaminated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a laminate for a hard disk drive (HDD) suspension, and more particularly to a method for manufacturing a laminate for an HDD suspension using an ultrathin copper foil.

  As the capacity of HDD suspensions is increased, most of the suspensions used in the past have been replaced by suspensions with integrated wiring that have stable buoyancy and positional accuracy relative to the disk that is the storage medium. ing. Among these wiring integrated suspensions, there is a type called a TSA (trace suspension assembly) method in which a laminate of stainless steel foil-polyimide resin-copper foil is processed into a predetermined shape by etching.

  The TSA suspension can easily form flying leads by laminating high-strength alloy copper foils, and has a high degree of freedom in shape processing and is relatively inexpensive and has good dimensional accuracy. Widely used. Here, an HDD suspension laminate in which a polyimide resin layer and a conductor layer are successively formed on a stainless steel substrate has already been disclosed. For example, in WO98 / 08216 (Patent Document 1), an HDD suspension laminate is disclosed. In order to obtain a suitable laminate, there is described what defines the linear expansion coefficient of the polyimide resin layer and the adhesive force between the polyimide resin layer and the conductor layer. WO 2005/096299 (Patent Document 2) discloses a laminate for an HDD suspension having a conductor layer thickness of 10 μm or less. However, this laminated body has a problem that the conductor layer is thinned by chemically etching the conductor layer, and the facility is complicated and troublesome. Japanese Patent No. 3704920 (Patent Document 3) discloses a method of laminating a polyimide resin film and a copper foil by thermocompression bonding. However, when the copper foil is 10 μm or less, there is a problem that handling property by thermocompression bonding is not good and the copper foil is likely to be wrinkled.

  On the other hand, in recent years, a material using a composite copper foil composed of a release layer and an ultrathin copper foil layer on a carrier copper foil has been proposed. This copper foil can be applied to a casting method in which polyimide varnish is applied and imidized, and a laminating method in which a composite copper foil is thermocompression bonded to a polyimide film with an adhesive layer by high-temperature pressurization. A technique for producing a copper foil / polyimide laminate having a thickness of 5 μm or less has been proposed by a technique of peeling off the foil.

  As such a technique, in JP-A-2004-42579 (Patent Document 4), a copper-clad laminate is obtained by thermocompression-cooling a copper foil with a heat-resistant carrier and a thermocompression-bonding multilayer polyimide under pressure. A method is disclosed. However, in this method, in the process of thermocompression bonding and cooling, the apparatus becomes complicated because it is performed under pressure using a double belt press, and it is necessary to prepare a thermocompression-bonding multilayer polyimide film separately. was there. Japanese Patent Laid-Open No. 2003-340963 (Patent Document 5) discloses a method of obtaining a copper-clad laminate by thermocompression bonding a polyimide film to an ultrathin copper foil to which a support metal is bonded. . However, even in this method, it is necessary to separately prepare a thermocompression-bonding multilayer polyimide film, and the adhesive strength between the polyimide film and the metal foil is not sufficient, and the applied polyimide film requires a certain thickness. There is a problem that it is difficult to make the polyimide resin layer extremely thin. In JP 2003-53836 A (Patent Document 6), in order to suppress wrinkling of the polyimide film after thermal lamination, the protective material is kept lightly in close contact with the laminated plate during thermocompression bonding, and the protective material is applied after cooling. A method of peeling from a laminate is disclosed. However, even in this method, it is necessary to separately prepare a thermocompression-bonding multilayer polyimide film, and there is a troublesome use of a protective material.

WO98 / 08216 WO2005 / 096299 publication Japanese Patent No. 3704920 JP 2004-42579 A Japanese Patent Laid-Open No. 2003-340963 JP 2003-53836 A

  In view of the above-mentioned problems, the object of the present invention is to provide a method for manufacturing a laminate for an HDD suspension, which can cope with ultra-thinness, is capable of fine wiring processing, has no appearance defects with reduced wrinkles and curls, and An object of the present invention is to provide a method for manufacturing a laminate for an HDD suspension having excellent adhesion between a resin layer and an ultrathin copper foil.

  As a result of intensive research to achieve the above object, the present inventors have made the conductor layer ultra-thin and handleability in the laminating process accompanying ultra-thinning in order to meet the need for fine circuit wiring. Improved. Furthermore, in order to make the adhesiveness in a plane of a conductor layer and an insulating resin layer uniform, it discovered that the lamination | stacking by application | coating of the insulating resin solution to a conductor layer was good.

That is, the present invention provides a polyimide resin having a glass transition temperature of 350 ° C. or less by applying and drying a polyimide solution or a precursor resin solution on an ultrathin copper foil having a support metal layer bonded through a release layer. A layer to be a layer (A1) is formed, and a polyimide or precursor resin solution is applied to the layer surface to be the resin layer (A1) and dried to have a linear thermal expansion coefficient of 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ ( 1 / K) low thermal linear expansion polyimide resin layer (B) is formed, and a polyimide or precursor resin solution is applied and dried as a surface layer, and a glass transition temperature of 350 ° C. or less polyimide resin layer ( After forming the layer to be A2), curing or imidization is performed to form a laminate with a support having at least three polyimide resin layers, and then a stainless foil is used as the polyimide resin layer (A2) of the laminate. Overlap so that and touch , Heated above the glass transition temperature of the polyimide resin layer (A2), thermocompression bonded under pressure to form a multilayer laminate having a stainless steel foil, and then cooled below the glass transition temperature of the polyimide resin layer (A2), A method for producing a laminate for an HDD suspension using an ultrathin copper foil as a conductor layer, wherein the support metal layer is peeled from the multilayer laminate with a peel strength of 1 N / m or more and less than 100 N / m.

  Further, the present invention provides the above production method wherein the adhesive strength between the ultrathin copper foil and the polyimide resin layer (A1) and the adhesive strength between the stainless steel foil and the polyimide resin layer (A2) are both 0.5 kN / m or more. It is. Furthermore, the present invention is such that the thickness of the ultrathin copper foil is 10 μm or less, the total thickness of the polyimide resin layer is 5 to 50 μm, the thickness of the stainless steel foil is 10 to 100 μm, and the support metal layer is It is said manufacturing method which satisfies any one or more that it is copper or a copper alloy, the thickness of a support metal layer is 5-100 micrometers metal foil, or a peeling layer is an inorganic type peeling layer.

  In the present invention, the polyimide resin layer having a glass transition temperature of 350 ° C. or lower is formed by 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane, 2,2-bis [4- (4-aminophenoxy). ) Phenyl] propane, 1,3-bis- (3-aminophenoxy) benzene, paraphenylenediamine, 3,4'-diaminodiphenyl ether and 4,4'-diaminodiphenyl ether, and anhydrous pyro Mellitic acid, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride and 3,3 ', 4,4'-diphenyl It is said manufacturing method which is a polyimide resin obtained by reacting with 1 or more types of acid anhydride components chosen from sulfonetetracarboxylic dianhydride.

  Furthermore, the present invention provides a low thermal linear expansion polyimide resin layer comprising 4,4′-diamino-2,2′-dimethylbiphenyl, 4,4′-diamino-2′-methoxybenzanilide, 3,4′-diamino. One or more diamines selected from diphenyl ether, 4,4'-diaminodiphenyl ether and 4,4'-bis (4-aminophenoxy) biphenyl, pyromellitic anhydride and 3,3 ', 4,4'-biphenyltetra It is said manufacturing method which is a polyimide resin obtained by reacting with 1 or more types of acid anhydrides chosen from carboxylic dianhydride.

  Hereinafter, the present invention will be described in detail.

In the production method of the present invention, a multilayer polyimide resin layer is formed by applying and drying a polyimide solution or a precursor resin solution on an ultrathin copper foil bonded to a support metal layer via a release layer. However, the present invention is not limited to this, as long as representative examples of the layer structure of the HDD suspension laminate that can be manufactured by the present invention are shown in (1) to (4). Here, a polyimide resin layer having a glass transition temperature of 350 ° C. or lower is referred to as a polyimide resin layer (A), and a low thermal expansion polyimide having a linear thermal expansion coefficient of 10 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K). The resin layer is referred to as a polyimide resin layer (B). In the following layer structure, M1 is an ultrathin copper foil, M2 is a stainless steel foil, (A1) is a polyimide resin layer (A) having a glass transition temperature of 350 ° C. or lower, and a layer in contact with M1 (A2 ) Means a polyimide resin layer (A) that is in contact with M2.

(1) M1 / (A1) / (B) / (A2) / M2
(2) M1 / (A1) / (B1) / (B2) / (A2) / M2
(3) M1 / (A1) / (B1) / (A3) / (B2) / (A2) / M2
(4) M1 / (A1) / (B1) / (C) / (B2) / (A2) / M2

  Here, the polyimide resin layer (A) having a glass transition temperature of 350 ° C. or lower has at least two layers. In this case, the polyimide resin layer in contact with M1 is a polyimide resin layer (A1), and the polyimide resin layer in contact with M2 is a polyimide resin layer (A2). When present in the intermediate layer, the polyimide resin layers are designated as polyimide resin layers (A3) and (A4) in order from the layer closer to M1. The low thermal expansion polyimide resin layer (B) is present between the polyimide resin layer (A1) and the polyimide resin layer (A2), but may be present in two or more layers. When there are two or more layers, they are (B1), (B2), etc. in order from the layer closer to M1. The polyimide resin layer (A) (A1), (A2) and (A3) may be the same or different in type and thickness of the polyimide resin. The same applies to (B1) and (B2) which are the polyimide resin layers (B). Moreover, the other polyimide resin layer (C) which does not correspond to any of a polyimide resin layer (A) and a polyimide resin layer (B) can also be used. Of the layer structures (1) to (4) of the laminate, a preferable layer structure is (1).

  In the production method of the present invention, since the polyimide resin layer is formed by applying a polyimide solution or a precursor solution, the thickness of the polyimide resin layer to be formed can be easily controlled. Further, the total thickness of the polyimide resin layer in the laminate for HDD suspension that can be manufactured according to the present invention is preferably 5 to 50 μm. More preferably, it is 5-20 micrometers. If the total thickness of the polyimide resin layer is less than 5 μm, the reliability of electrical insulation tends to decrease, while if it exceeds 50 μm, the drying efficiency tends to decrease when the polyimide resin layer is formed.

  The polyimide resin as used in the present invention includes polyimide resins constituting the polyimide resin layers (A) and (B), and structures such as polyimide, polyamideimide, polybenzimidazole, polyimide ester, polyetherimide, and polysiloxaneimide. A heat-resistant resin made of a polymer having an imide group therein. A method of synthesizing a polyimide resin by using a diamine and an acid anhydride in an organic solvent is suitable. In this case, the polyimide resin is understood by explaining the diamine and the acid anhydride.

  The polyimide resin which comprises the polyimide resin layer (A) whose glass transition temperature used by this invention is 350 degrees C or less can use a well-known polyimide resin. Although the glass transition temperature of a polyimide resin layer (A) needs to be 350 degrees C or less, Preferably it is 200-320 degreeC.

  Preferred diamines used for synthesizing the polyimide resin constituting the polyimide resin layer (A) include 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane (DANPG), 2,2 -Bis [4- (4-aminophenoxy) phenyl] propane (BAPP), 1,3-bis- (3-aminophenoxy) benzene (APB), paraphenylenediamine (p-PDA), 3,4'-diamino There is one or more diamines selected from diphenyl ether (DAPE34) and 4,4′-diaminodiphenyl ether (DAPE44). Preferred acid anhydrides include pyromellitic anhydride (PMDA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 3,3 ′, 4,4′-benzophenone tetra There are one or more acid anhydrides selected from carboxylic dianhydride (BTDA) and 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA). About the said diamine and an acid anhydride, only 1 type may respectively be used and it can also be used in combination of 2 or more type. By using the above diamine and acid anhydride, the adhesiveness with ultrathin copper foil or stainless steel foil is improved.

The polyimide resin constituting the low thermal expansion polyimide resin layer (B) having a linear thermal expansion coefficient of 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K) used in the present invention is a known low thermal expansion polyimide resin. Can be used. The linear thermal expansion coefficient of the polyimide resin layer (B) needs to be 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K), preferably 1 × 10 ^{−6 to} 25 × 10 ⁻⁶ (1 / K), more preferably 1 × 10 ^{−6 to} 20 × 10 ⁻⁶ (1 / K).

  Preferred diamines used in the synthesis of the polyimide resin constituting the polyimide resin layer (B) include 4,4′-diamino-2,2′-dimethylbiphenyl (m-TB), 4,4′-diamino- Selected from 2'-methoxybenzanilide (MABA), 3,4'-diaminodiphenyl ether (DAPE34), 4,4'-diaminodiphenyl ether (DAPE), 4,4'-bis (4-aminophenoxy) biphenyl (BAPB) There are one or more diamines. Preferred acid anhydrides include one or more acid anhydrides selected from pyromellitic anhydride (PMDA) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA). About diamine and an acid anhydride, only 1 type may be used, respectively, and 2 or more types can also be used together. By using the diamine and acid anhydride described above, thermal dimensional stability during lamination can be maintained.

  Examples of the solvent used for the synthesis of the polyimide resin or the precursor resin include N, N-dimethylacetamide (DMAc), n-methylpyrrolidinone, 2-butanone, diglyme, xylene, and the like, one or more of these. It can also be used in combination.

  The synthesized polyimide resin or precursor resin is used as a solution. Usually, it is advantageous to use as a reaction solvent solution, but if necessary, it can be concentrated, diluted or replaced with another organic solvent. In addition, since the polyimide precursor resin is generally excellent in solvent solubility, it is advantageously used. These resin solutions are sequentially applied and dried so as to form a predetermined layer structure on the ultrathin copper foil with the support metal layer. The layer thickness is such that the polyimide resin layer (B) is 50% or more of the whole, preferably 70% or more, and the polyimide resin layer (A) has a thickness that can ensure adhesion with an ultrathin copper foil or stainless steel foil. If it is.

  After applying a polyimide solution (or precursor resin solution) on an ultrathin copper foil with a support metal layer and repeating a drying operation to form a predetermined polyimide resin layer (or precursor resin layer), In order to cure (or imidize) an uncured polyimide resin (or precursor resin), it is usually heated to a temperature of 150 ° C. or higher. The laminate obtained after the heat treatment or curing (or imidization) is completed is subjected to the next step.

  The stainless steel foil was overlapped so as to be in contact with the polyimide resin layer (A2) on the surface of the laminate, and the laminate and the stainless steel foil were thermocompressed under pressure to obtain a multilayer laminate, which was cooled in a state where the pressure was released. Thereafter, the support metal layer is peeled from the multilayer laminate to obtain an HDD suspension laminate using an ultrathin copper foil as a conductor layer.

The method of thermocompression bonding is not particularly limited, and a known method can be appropriately employed. Examples of the method of laminating the resin layer (A2) of the laminate and the stainless steel foil include a normal hydro press, a vacuum type hydro press, an autoclave pressure type vacuum press, and a continuous thermal laminator. Among the methods of laminating stainless steel foil, vacuum hydropress and continuous thermal laminator are used from the viewpoint that sufficient press pressure can be obtained, residual volatiles can be easily removed, and oxidation of the conductor can be prevented. It is preferable. In addition, when the stainless steel foil is laminated in this way, it can be thermocompression bonded by heating above the glass transition temperature of the polyimide resin layer (A2). The heating temperature at the time of thermocompression bonding is the polyimide resin layer (A2). It is preferably 20 ° C. or higher and 400 ° C. or lower than the glass transition temperature. By increasing the glass transition temperature of the polyimide resin layer (A2) by 20 ° C. or more, the orientation of the polyimide resin film is improved, and a laminate for HDD suspension with good flatness can be easily obtained. If it is 400 ° C. or higher, thermal decomposition of the polyimide resin begins to occur gradually, which is not preferable. The press pressure is usually about 100 to 150 kgf / cm ² although it depends on the type of press equipment used.

  Moreover, when cooling under pressure release after thermocompression bonding, the cooling temperature needs to be lower than the glass transition temperature of the polyimide resin layer (A), preferably the polyimide resin layers (A1) and (A2), Preferably, it is cooled to a temperature that is 20 ° C. or more lower than the glass transition temperature of the polyimide resin layer (A), more preferably 30 ° C. or lower. When the support metal layer is peeled from the multilayer laminate at a temperature equal to or higher than the glass transition temperature of the polyimide resin layer (A), wrinkles and curls are likely to occur in the HDD suspension laminate.

  In the multilayer laminate or HDD laminate produced according to the present invention, the adhesive strength between the ultrathin copper foil and the polyimide resin layer (A1) is 0.5 kN / m or more, preferably 0.8 kN / m or more. It is good. The adhesive strength between the stainless steel foil and the polyimide resin layer (A2) is 0.5 kN / m or more, preferably 0.8 kN / m or more. Here, the term “adhesive strength” refers to a 1 mm width of metal foil and a 90 ° peeling method (JIS C6471).

  The peel strength between the support metal layer and the ultrathin copper foil is 1 N / m or more and less than 100 N / m. It is preferably 1 N / m or more and less than 50 N / m, more preferably 3 N / m or more and 15 N / m or less, and further preferably 4 N / m or more and 10 N / m or less. When the peel strength is less than 1 N / m, the ultrathin copper foil may peel from the support metal layer in the thermocompression bonding process between the polyimide resin layer and the stainless steel foil, which causes a problem in stable operation. On the other hand, if the peel strength exceeds 100 N / m, the laminated body after peeling of the support metal is likely to warp. The peel strength here refers to a metal foil 1 mm width, 90 ° peeling method (JIS C6471). The peel strength can be changed (by using a release agent or a low-tack material) by adjusting the adhesive strength between the support metal layer and the ultrathin copper foil.

  By peeling the support metal layer from the multilayer laminate having the ultrathin copper foil layer with the support metal layer, an HDD suspension laminate is obtained. The peeling angle of the support metal layer at the time of peeling is preferably 90 ° or more with respect to the traveling direction of the HDD suspension laminate. By setting the peeling angle to 90 ° or more, curling of the HDD suspension laminate after peeling of the support metal layer can be suppressed. When the peeling angle of the support metal layer is less than 90 °, it is necessary to give sufficient tension to the HDD suspension laminate with respect to the advancing direction surface, and the HDD suspension laminate after peeling the support metal layer. Cause curling.

  In addition, the thickness range of the ultrathin copper foil used in the present invention is preferably 0.1 to 10 μm, more preferably 0.1 to 5 μm, and still more preferably 0.1 to 5 μm. . The ultrathin copper foil means a pure copper or copper alloy foil, and the ultrathin copper foil is bonded to the support metal layer through a release layer. The surface roughness of the ultrathin copper foil is not particularly defined, but from the viewpoint of flash etching property, Rz JIS = 2.0 μm or less is preferable, and Rz JIS = 1.5 μm or less is more preferable. In addition, said Rz shows the ten-point average roughness (JIS B0601-1994) in surface roughness.

  The stainless steel layer used in the present invention is not particularly limited, but from the viewpoint of spring characteristics and dimensional stability, a highly elastic and high strength stainless steel foil such as SUS304 is preferable and annealed at a temperature of 300 ° C. or higher. SUS304 is particularly preferred. The range of the thickness of the stainless steel layer used is preferably 10 to 100 μm, more preferably 15 to 70 μm, and still more preferably 15 to 50 μm. If the thickness of the stainless steel layer is less than 10 μm, there is a problem that it is impossible to secure a spring property that sufficiently suppresses the flying height of the slider. Become.

  The thickness of the support metal layer used in the present invention is preferably 5 to 100 μm in order to obtain stable transportability. More preferably, it is 12-50 micrometers. The thickness of the support metal layer is preferably selected as appropriate depending on the thickness of the ultrathin copper foil used as the laminate. In view of handling properties when laminating the polyimide resin layer, the total thickness range of the ultrathin copper foil and the support metal layer is more preferably 12 to 50 μm.

  In addition, the material used for the support metal layer is preferably heat-resistant, and is preferably copper or a copper alloy in consideration of cost.

  In order to use the multilayer laminate obtained through the laminating step by heating and pressurizing as an HDD suspension, a step of peeling from the peeling layer between the support metal and the ultrathin copper foil is performed. For this reason, the release layer according to the present invention is required to have a small change in peel strength due to heating temperature and to have a stable peel strength, and is preferably an inorganic release layer composed of an inorganic substance. More preferably, it contains any of Ni, Cr, and Co.

  The laminate for HDD suspension obtained by the production method of the present invention has excellent adhesion strength between ultrathin copper foil / and stainless steel foil and polyimide resin layer, and the copper foil thickness can be arbitrarily set to 0.1 μm to 10 μm. There is an advantage that the thickness of the resin layer can be arbitrarily set to 10 to 50 μm. In addition, it is possible to provide a highly reliable HDD suspension with high reliability in response to the demand for a HDD suspension with high density and ultra-fine wiring.

  Unless otherwise specified in the examples of the present invention, various measurements and evaluations are as follows.

[Measurement of thickness]
The laminate after peeling off the support metal layer from the ultrathin copper foil layer was cut into a strip test piece having a width of 305 mm and a length of 10 mm, and using a dial gauge (manufactured by Mitutoyo), the thickness was 30 points at 10 mm intervals in the width direction. Was measured. Thereafter, the copper part was etched, and the thickness of the stainless steel layer / polyimide resin layer bilayer was measured in the same manner. The thickness of the ultrathin copper foil was calculated from the difference between the two thicknesses.

[Measurement method of adhesive strength between polyimide resin layer and ultra-thin copper foil]
After peeling the support metal layer from the ultra-thin copper foil layer, electrolytic copper plating is performed on the ultra-thin copper foil, the thickness of the ultra-thin copper foil is 12 μm, and Tensilon tester (manufactured by Toyo Seiki Seisakusho) is used. Then, the resin side of a copper clad product having a width of 1 mm was fixed to a stainless steel plate with a double-sided tape, and copper was peeled off at a rate of 50 mm / min in the 90 ° direction.

[Measurement method of peel strength between support metal layer and ultra-thin copper foil]
Using a Tensilon tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the copper foil side of the sample with a width of 1 mm was fixed to the stainless steel plate with double-sided tape, and the support metal layer was peeled off at a rate of 50 mm / min in the 90 ° direction. Asked.

[Measurement of surface roughness of ultra-thin copper foil]
Using an ultra-deep shape measurement microscope (manufactured by KEYENCE, VK-8500), measurement was performed at a magnification of 2000 times in the length direction of the ultrathin copper foil surface by 140 μm. The ultrathin copper foil surface here means the surface opposite to the support metal layer side in the ultrathin copper foil to which the support metal layer is bonded.

[Measurement of glass transition temperature]
Using a viscoelasticity analyzer (RSA-II, manufactured by Rheometric Science Effy Co., Ltd.), using a 10 mm wide sample, raising the temperature from room temperature to 400 ° C. at a rate of 10 ° C./min while applying 1 Hz vibration Of the loss tangent (Tan δ).

[Measurement of thermal linear expansion coefficient]
Using a thermomechanical analyzer (manufactured by Seiko Instruments Inc.), the temperature was raised to 250 ° C., held at that temperature for 10 minutes, cooled at a rate of 5 ° C./minute, and the average thermal linear expansion from 240 ° C. to 100 ° C. The coefficient was obtained.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to this.
The abbreviations used in this example are as described above.

Synthesis example 1
In a 500 ml separable flask, 29.5 g (0.1 mol) of APB was dissolved in 367 g of DMAc with stirring. Next, 9.1 g (0.04 mol) of PMDA and 20.2 g (0.06 mol) of BTDA were added to the solution in a nitrogen stream. Thereafter, stirring was continued for about 3 hours to conduct a polymerization reaction, and a viscous polyimide precursor resin liquid A was obtained.

Synthesis example 2
In a 500 ml separable flask, 30.3 g (0.1 mol) of DANPG was dissolved in 352 g of DMAc with stirring. Next, 9.3 g (0.04 mol) of PMDA and 20.5 g (0.06 mol) of BTDA were added to the solution in a nitrogen stream. Thereafter, stirring was continued for about 3 hours to conduct a polymerization reaction, and a viscous polyimide precursor resin liquid B was obtained.

Synthesis example 3
In a 500 ml separable flask, 20.7 g (0.08 mol) of MABA was dissolved in 343 g of DMAc with stirring. Next, 28.5 g (0.13 mol) of PMDA and 10.3 g (0.05 mol) of DAPE were added to the solution in a nitrogen stream. Thereafter, stirring was continued for about 3 hours to conduct a polymerization reaction, and a viscous polyimide precursor resin liquid C was obtained.

Example 1
The resin liquid A of Synthesis Example 1 was applied to an ultrathin copper foil with a support copper foil layer (manufactured by Nippon Electrolytic Co., Ltd. YSNAP-3B, support copper foil thickness 18 μm, ultrathin copper foil thickness 3 μm, inorganic release layer), After drying at 130 ° C. for 5 minutes to form the resin layer 1A, the resin liquid C of Synthesis Example 3 was further coated on the resin layer, and dried at 130 ° C. for 10 minutes to form the resin layer 1C. The resin liquid A of Synthesis Example 1 was applied on the resin layer, dried at 130 ° C. for 5 minutes to form a resin layer 1A, and heated to 380 ° C. over 15 minutes to perform an imidization reaction. A laminate with a support was obtained.

Next, the laminated body with a support obtained by the above method and a stainless steel foil (manufactured by Nippon Steel Corp., SUS304, tension annealed product, thickness 20 μm) are surfaced using a vacuum press. A laminate for HDD suspension is formed by heat-pressing under the conditions of a pressure of 150 kg / cm ² , a temperature of 320 ° C., and a press time of 20 minutes to form a multilayer laminate, cooling to 50 ° C., and then peeling the support copper foil. Got the body. The peel strength between the support copper foil and the ultrathin copper foil at this time was 10 N / m, and the appearance of the HDD suspension laminate was also good. The total thickness of the polyimide resin layer was 10 μm, the glass transition temperature of the resin layer 1A was 218 ° C., and the thermal linear expansion coefficient of the resin layer 1B was 14.6 × 10 ⁻⁶ (1 / K). The adhesive strength between the ultrathin copper foil and the polyimide resin layer was 1.1 kN / m, and the adhesive strength between the stainless steel foil and the imide resin layer was 1.2 kN / m.

Example 2
Resin of Synthesis Example 1 on ultrathin copper foil with support copper foil layer (NIPPON ELECTRIC YSNAP-3B, support copper foil thickness 18 μm, ultrathin copper foil thickness 1 μm, inorganic release layer) After applying the liquid A and drying at 130 ° C. for 5 minutes to form the resin layer 2A, the resin liquid C of Synthesis Example 3 was applied, and drying at 130 ° C. for 10 minutes to form the resin layer 2C. Further, the resin liquid B of Synthesis Example 2 was applied on the resin layer, dried at 130 ° C. for 5 minutes to form a resin layer 2B, and heated to 360 ° C. over 15 minutes to perform an imidization reaction. Thus, a laminate with a support was obtained.

Next, the laminated body with a support obtained by the above method and a stainless steel foil (manufactured by Nippon Steel Corp., SUS304, tension annealed product, thickness 20 μm) are surfaced using a vacuum press. A laminate for an HDD suspension is formed by heat-pressure bonding under conditions of a pressure of 150 kg / cm ² , a temperature of 320 ° C., and a press time of 20 minutes to cool the laminate to 50 ° C., and then peeling the support copper foil. Got. The peel strength between the support copper foil and the ultrathin copper foil at this time was 10 N / m, and the appearance of the HDD suspension laminate was also good. The total thickness of the polyimide resin layer is 10 μm, the glass transition temperatures of the resin layers 2A and 2C are 218 ° C. and 220 ° C., respectively, and the thermal linear expansion coefficient of the resin layer 2B is 14.6 × 10 ⁻⁶ (1 / K). Met. The adhesive strength between the ultrathin copper foil and the polyimide resin layer was 1.2 kN / m, and the adhesive strength between the stainless steel foil and the imide resin layer was 1.2 kN / m.

Comparative Example 1
Instead of using ultrathin copper foil with support copper foil layer (NIPPON ELECTRIC YSNAP-3B, support copper foil thickness 18 μm, ultrathin copper foil thickness 3 μm, inorganic release layer), using copper foil 5 μm, A laminate was produced in the same manner as in Example 1. As for the obtained laminated body, the wrinkle by the side of copper foil was recognized.

Claims (10)

A polyimide solution or precursor resin solution is applied and dried on an ultrathin copper foil to which a support metal layer is bonded via a release layer to form a polyimide resin layer (A1) having a glass transition temperature of 350 ° C. or lower. A layer is formed, and a polyimide or precursor resin solution is applied to the surface of the resin layer (A1) and dried to obtain a low thermal linear expansion having a linear thermal expansion coefficient of 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K). A layer to be a polyimide resin layer (B) was formed, and a polyimide or precursor resin solution was applied and dried as a surface layer to form a layer to be a polyimide resin layer (A2) having a glass transition temperature of 350 ° C. or lower. Thereafter, curing or imidization is performed to form a laminate with a support having at least three polyimide resin layers, and then a stainless steel foil is superposed so as to be in contact with the polyimide resin layer (A2) of the laminate. Glass rolling of resin layer (A2) Heat to above the temperature, thermocompression bonding under pressure to make a multilayer laminate having a stainless steel foil, then cool to below the glass transition temperature of the polyimide resin layer (A2), and then the support metal layer from the multilayer laminate A method for producing a laminate for an HDD suspension using a very thin copper foil as a conductor layer, wherein the laminate is peeled at a peel strength of 1 N / m or more and less than 100 N / m.   The adhesive strength between the ultra-thin copper foil and the polyimide resin layer (A1) is 0.5 kN / m or more, and the adhesive strength between the stainless steel foil and the polyimide resin layer (A2) is 0.5 kN / m or more. The method for manufacturing a laminate for an HDD suspension according to claim 1.   The method for manufacturing a laminate for an HDD suspension according to claim 1 or 2, wherein the ultrathin copper foil has a thickness of 10 µm or less.   The method for producing a laminate for an HDD suspension according to any one of claims 1 to 3, wherein the total thickness of the polyimide resin layer is 5 to 50 µm.   The method for producing a laminate for an HDD suspension according to any one of claims 1 to 4, wherein the stainless steel foil has a thickness of 10 to 100 µm.   6. The method for manufacturing a laminate for an HDD suspension according to claim 1, wherein the thickness of the support metal layer is a metal foil having a thickness of 5 to 100 [mu] m.   A polyimide resin layer having a glass transition temperature of 350 ° C. or lower is composed of 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, One or more diamines selected from 1,3-bis- (3-aminophenoxy) benzene, paraphenylenediamine, 3,4'-diaminodiphenyl ether and 4,4'-diaminodiphenyl ether, pyromellitic anhydride, 3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride and 3,3 ', 4,4'-diphenylsulfone tetracarboxylic dianhydride The method for producing a laminate for an HDD suspension according to any one of claims 1 to 6, which is a polyimide resin obtained by reacting at least one acid anhydride component selected from anhydrides.   Low thermal linear expansion polyimide resin layer is 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2'-methoxybenzanilide, 3,4'-diaminodiphenyl ether, 4,4 One or more diamines selected from '-diaminodiphenyl ether and 4,4'-bis (4-aminophenoxy) biphenyl, pyromellitic anhydride and 3,3', 4,4'-biphenyltetracarboxylic dianhydride The method for producing a laminate for an HDD suspension according to claim 1, wherein the HDD suspension is a polyimide resin obtained by reacting with one or more acid anhydrides selected from the group consisting of:   The method for producing a laminate for an HDD suspension according to claim 1, wherein the support metal layer is copper or a copper alloy.   The method for manufacturing a laminate for an HDD suspension according to claim 1, wherein the release layer is an inorganic release layer.