JP2006281582A - Copper-clad laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-clad laminate with a copper foil layer having enough mechanical strength to be used in applications requiring mechanical strength such as a connector. <P>SOLUTION: The laminate comprises at least a conductor layer and an insulating resin layer. In the copper-clad laminate, copper foil or copper alloy foil to be the conductor layer has a modulus of elasticity of 100-150 GPa, a strength of 600-1,000 MPa, and a thickness of 20-100 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laminate used for connectors, bumps, etc., the copper foil or copper alloy foil serving as the conductor layer has an elastic modulus in the range of 100 Gpa to 150 Gpa, a strength of 600 to 1000 Mpa, and a thickness of A copper-clad laminate characterized by being in the range of 20 μm to 100 μm.

  Copper-clad laminates are used in various electrical products as electrical circuits. In order to meet the demand for smaller and thinner electrical products, there is a demand for smaller and thinner parts. Conventionally, in the connector, the connecting terminal portion has a shape in which rod-shaped pins are arranged. However, a method of making a spiral connecting terminal with a copper alloy by an etching method has been developed (Patent Document 1). In such applications, mechanical strength is required for the copper foil.

When it is going to give mechanical strength to copper foil, the method of respond | corresponding by thickening copper foil can be considered easily. However, the thickness of the copper foil is determined by the electric capacity and the processability of the circuit, and a thin copper foil is used due to the miniaturization of the circuit. Although it has occurred, no method has been introduced so far for improving the mechanical strength of a thin copper foil corresponding to a fine circuit in a connector or the like.
JP 2004-327182 A

  Accordingly, an object of the present invention is to provide a copper-clad laminate having a copper foil layer having sufficient mechanical strength for applications requiring mechanical strength such as connectors.

  The present inventors have studied the mechanical strength, particularly the elastic modulus, strength, and thickness of the laminated copper foils, and have completed the invention by defining suitable ranges.

  That is, the present invention is a laminate comprising at least a conductor layer and an insulating resin layer, the copper foil or alloy copper foil serving as the conductor layer has an elastic modulus in the range of 100 Gpa to 150 Gpa, and the strength is 600 to 1000 Mpa. The copper-clad laminate is characterized by having a thickness in the range of 20 μm to 100 μm.

  According to the laminate of the present invention, it is possible to provide a copper-clad laminate having a copper foil layer having sufficient mechanical strength for uses such as connectors that require mechanical strength.

  The best mode for carrying out the present invention will be described below. The copper-clad laminate of the present invention comprises a support layer (can be omitted) / insulating resin layer / conductor layer. The support layer in the present invention is not particularly limited and can be used without being used, but if used, it should have a thermal expansion coefficient close to that of the conductor layer and the insulating resin layer and should have heat resistance of 400 ° C. SUS304 annealed at a temperature of 300 ° C. or higher is preferable. Further, the thickness of such stainless steel is preferably in the range of 10 to 50 μm, and particularly preferably in the range of 18 to 30 μm.

  The resin constituting the insulating resin layer is not particularly limited as long as it has high electrical insulating properties such as polyimide, polyamideimide, polyetherimide, epoxy, and liquid crystal resin, and has good adhesion to the support layer and the conductor layer. When the insulating resin layer is made of polyimide, the thickness of the insulating resin layer is preferably 10 to 20 μm.

  The conductor layer in the present invention is formed from a copper foil or an alloy copper foil. Here, the alloy copper foil refers to an alloy copper foil containing copper as an essential component and containing at least one different element other than copper, such as chromium, zirconium, nickel, silicon, zinc, and beryllium. The content is 90% by weight or more.

The copper foil or alloy copper foil used for the conductor layer of the present invention is required to have an elastic modulus in the range of 100 to 150 GPa. The elastic modulus is a requirement to ensure the resistance to bending stress of the conductor layer, and if it is less than 100Gpa, it will not absorb the stress applied when mounting components such as semiconductor devices, and defects such as circuit breakage may occur. Cause. On the other hand, if it is larger than 150 Gpa, there is a problem in that the resistance increases and the connection reliability after component mounting decreases.
Moreover, the copper foil or alloy copper foil used for the conductor layer of the present invention is required to have a strength in the range of 600 to 1000 MPa. The strength is necessary to ensure resistance against impacts on the metal foil. If the strength is smaller than this range, the circuit may break due to external impacts during circuit processing, component mounting, and even when used as a circuit component. It is not preferable. Moreover, even if it is larger than this range, it is not meaningful because it becomes over-spec in practice.

  Next, the manufacturing method of the copper clad laminated board of this invention is demonstrated. In producing a copper-clad laminate, first, after applying a resin solution on a roll-wound sheet-like substrate of a support layer or a conductor layer constituting one side, continuously heat treatment in a drying step and a curing step, It is preferable to obtain a single-sided flexible substrate by roll winding.

  Thus, after forming the resin layer on one side of the sheet-like substrate, the copper foil or alloy copper foil (the elastic modulus is in the range of 100 Gpa to 150 Gpa, and the strength is 600 MPa to form the other side on this resin layer. 1000Mpa and a thickness in the range of 20 μm to 100 μm and a thickness of 20 to 50 μm) are superposed and thermocompression bonded to form a laminate comprising a support layer / resin layer / conductor layer. The thermocompression bonding conditions may be integrated continuously with a pressure roll, or may be cut into a predetermined size by a batch method, and a plurality of layers may be laminated and pressed. Such thermocompression bonding conditions need to be changed according to the resin layer to be used.

Hereinafter, the present invention will be described in more detail with reference to examples. The abbreviations used in the synthesis examples are as follows.
PMDA: pyromellitic anhydride
BTDA: Benzophenone-3,4,3 ', 4'-tetracarboxylic dianhydride
DSDA: Diphenylsulfone-3,4,3 ', 4'-tetracarboxylic dianhydride
DA-NPG: 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane
MABA: 4-amino-N- (4-amino-2-methoxyphenyl) -benzamide
DAPE: 4,4'-diaminodiphenyl ether
p-PDA: p-phenylenediamine
DMAc: N, N-dimethylacetamide

[Synthesis Example 1]
5.5 mol of DA-NPG and 3.5 mol of 3,4′-DAPE were weighed and dissolved in 25.5 kg of solvent DMAc with stirring in a 40 L planetary mixer. Next, 2.5 mol of PMDA and 5.0 mol of BTDA were added, and the polymerization reaction was continued for 3 hours at room temperature to obtain a viscous polyimide precursor A solution.

[Synthesis Example 2]
8.5 mol of MABA and 2.0 mol of DAPE were weighed and dissolved in 25.5 kg of solvent DMAc with stirring in a 40 L planetary mixer. Next, 8.6 mol of PMDA was added, and the polymerization reaction was continued by stirring at room temperature for 3 hours to obtain a viscous polyimide precursor B solution.

[Synthesis Example 3]
5.5 mol of APB and 3.9 mol of p-PDA were weighed and dissolved in 25.5 kg of solvent DMAc with stirring in a 40 L planetary mixer. Next, 5.4 mol of DSDA and 2.3 mol of PMDA were added, and stirring was continued at room temperature for 3 hours to conduct a polymerization reaction, whereby a solution of a viscous polyimide precursor C was obtained.

  A stainless steel foil (manufactured by Nippon Steel Co., Ltd., SUS304, tension annealed product, thickness 20 μm) was used as a support layer, and a polyimide precursor resin solution A as a lower layer, a polyimide precursor resin solution B as an intermediate layer, and a top layer. Three layers were applied to the outer layer so that the polyimide layer thickness after curing the polyimide precursor resin solution A would be 18 μm, dried at 110 ° C. for 3 minutes, and then several steps in the range of 130 to 360 ° C. for 3 minutes each. The imidization was completed by stepwise heat treatment to obtain a laminate having a polyimide resin layer on stainless steel.

Next, rolled copper alloy foil 1 (C7025, copper foil thickness 44 μm) manufactured by Japan Energy Co., Ltd. is overlaid as a batch treatment, and heated using a vacuum press machine under conditions of a surface pressure of 15 Mpa, a temperature of 320 ° C., and a press time of 20 minutes. The target copper-clad laminate was obtained by pressure bonding.
This copper-clad laminate was processed into a test board having 100 0.3 mm spiral connector portions as described in Patent Document 1, and the connection failure occurrence rate of each connector portion was evaluated. The evaluation results are shown in Table 1.

  Rolled copper alloy foil 2 (C7025, copper foil thickness 20 μm) manufactured by Japan Energy Co. is used as the conductor layer, and the polyimide precursor resin solution A is used as the lower layer, the polyimide precursor resin solution B as the intermediate layer, and the polyimide precursor as the outermost layer. Three layers were applied so that the polyimide layer thickness after curing with body resin solution C would be 18 μm, dried at 110 ° C. for 3 minutes, and then in several steps at 130 to 360 ° C., stepwise heat treatment for 3 minutes each. Thus, imidization was completed to obtain a copper-clad laminate having a polyimide resin layer on the conductor layer. The results evaluated in the same manner as in Example 1 are shown in Table 1.

[Comparative Example 1]
As the conductor layer, Furukawa Electric Co., Ltd. electrolytic copper foil 3 (F2-WS, copper foil thickness 12 μm) was used. On top of this, polyimide precursor resin solution A was used as the lower layer, polyimide precursor resin solution B as the intermediate layer, and polyimide as the outermost layer. Three layers were applied so that the thickness of the polyimide layer after curing with the precursor resin solution C was 18 μm, dried at 110 ° C. for 3 minutes, and then several steps in the range of 130 to 360 ° C., each step for 3 minutes. Imidization was completed by heat treatment to obtain a copper-clad laminate having a polyimide resin layer on the conductor layer. The results evaluated in the same manner as in Example 1 are shown in Table 1.

Claims (3)

  A laminate comprising at least a conductor layer and an insulating resin layer, wherein the copper foil or alloy copper foil serving as the conductor layer has an elastic modulus in the range of 100 Gpa to 150 Gpa, a strength of 600 to 1000 Mpa, and a thickness of A copper-clad laminate characterized by being in the range of 20 μm to 100 μm.   The copper-clad laminate according to claim 1, wherein the insulating resin layer is polyimide.   The copper-clad laminate according to claim 2, wherein the insulating resin layer made of polyimide has a thickness of 10 to 20 µm.