JPH03218825A - Laminate - Google Patents

Abstract

PURPOSE:To obtain a laminate excellent in electrical characteristics, dimensional stability, heat resistance and drill processability by laminating a homopolymer or copolymer of a specific fluorice-containing divinyl ether compound on a metal. CONSTITUTION:A laminate is formed by laminating a homopolymer or copoly mer of a fluorine-containing divinyl ether compound represented by general formula (I) (wherein j and k are respectively 0 or 1, l and m are respectively an integer of 0 or more, n is an integer of 2 or more and j, l and m are together 0 when k is 1) to a metal. Since the homopolymer or copolymer is obtained by bulk polymerization aiming at molding, a mixture prepared by adding a polymerization initiator and, if necessary, an inorg. powder and a filler to the monomer or the flowable prepolymer thereof is held between two flat plates and polymerization is advanced to obtain a flat polymer. In the case of replacement by cloth, a cloth reinforced flat polymer is obtained. The thickness of the polymer layer is pref. 0.05-2mm in a case used as a low dielec tric circuit board and, when the laminate is used as a printed circuit board, copper or aluminum of 0.1-50mum is pref.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a laminate suitable for a low dielectric circuit board having excellent electrical properties, dimensional stability, heat resistance, and drillability.

(Prior Art and Problems to be Solved by the Invention) In recent years, with the increase in speed and performance of large computers, development of low dielectric circuit boards has been progressing in order to reduce signal transmission delay time. Such low dielectric circuit boards have been developed using polybutadiene, polytetrafluoroethylene (PTFE), and recently, fluororesin (PFA) as low dielectric materials.

Among these, polybutadiene is flammable and has a high water absorption rate and dielectric constant, so it is not suitable as a low dielectric circuit board. In addition, although PTFE and PFA have a low dielectric constant, they have poor adhesion to metal foils, so etching is required before lamination, and dimensional accuracy cannot be achieved when drilling to create through holes. They have drawbacks such as difficulty in making holes, poor dimensional stability because these resins are thermoplastic, and high coefficient of thermal expansion.

Furthermore, in the case of conventional low dielectric circuit boards, polymer powders or pellets obtained by polymerization are mixed with inorganic powders such as silica, alumina, and fibers of glass, quartz, or polytetrafluoroethylene as fillers under pressure. Glass, molded by heating or polymer dispersion
A reinforced polymer film is created by impregnating a cloth such as quartz or Teflon and then baking it.Furthermore, in order to improve the adhesion to the metal foil, the polymer film is subjected to a process such as ethoching to coat the metal foil on one or both sides. Low dielectric circuit boards are manufactured by laminating layers, and manufacturing requires multiple steps.

(Means for Solving the Problems) In view of the above-mentioned problems, the present inventors conducted research on an improved low dielectric circuit board and a method for manufacturing the same. The compound or copolymer has a low dielectric constant, has excellent heat resistance, dimensional stability, and low thermal expansion, and has good drilling workability. Cast or 2
It was discovered that when the polymer was cast between sheets of metal foil and polymerized, the adhesion between the polymer and the metal foil was good, and the present invention was completed.

That is, the present invention is a laminate formed by laminating a homopolymer or copolymer of a fluorine-containing divinyl ether compound represented by the general formula (1) and a metal.

In the above general formula (I),! and m are each an integer of O or more, and n is an integer of 2 or more. However, when the obtained laminate is used as a low dielectric circuit board, e and m are each an integer of O to 2. , n is preferably an integer of 2 to 6.

Specific examples of the nitrogen-containing divinyl ether compounds preferably used in the present invention are as follows.

CF2=CFO(CFz)z~60CF=ChCFz=
CFOCHz (CFz)z~4cHzOcF=cFzC
F3 CFs CFz=CFOCHzCFO(CFz)z~bOcFc
HtOcF = CF! C.F. Ch=CFOChCFO(Ch)z~60CF=cpz
In the present invention, a homopolymer or a copolymer of the fluorine-containing divinyl ether compound represented by the general formula (1) may be used.

The copolymer may be a copolymer of the fluorine-containing divinyl ether compounds represented by the general formula (I), or may be a copolymer with other monomers. In this case, it is preferable that the monomer unit based on the fluorine-containing divinyl ether compound represented by the general formula (I) is 50 mol % or more.

As the above-mentioned other monomers, monomers copolymerizable with the fluorine-containing divinyl ether compound may be employed without any restriction. Examples include tetrafluoroethylene, tetrafluoropropylene, fluoroalkyl vinyl ether, and the like. Among these, in particular, the following general formula (n). However, a and C are each 0 or 1, b is an integer of 0 to 2, and d is an integer of 1 to 8.

A monovinyl ether compound represented by is preferably used. The specific compounds represented by the above general formula (II) are as follows.

CFz=CFO(Ch)g~. F Ch = CFOCHz (CFz) t~, FCPs CFz = CFOCH! CFO (CF!)
T~. FCF3 CFz=CFOCFzCFO(CFz)z-@F Homopolymerization of the fluorine-containing divinyl ether compound represented by the above general formula (I) and copolymerization with a monomer copolymerizable therewith are carried out by the following method. It will be done.

Organic radical generators are used as polymerization initiators for homopolymerization and copolymerization of fluorine-containing divinyl ether compounds. Since most of the fluorine-containing divinyl ether compounds used in the above have a low boiling point, fluorine-containing diacylver oxide, which generates radicals at low temperatures, is preferably used. Particularly in the present invention, those represented by the following general formula are preferably used.

X(Ch) rcOOc(CFz) tX11 00 11 00 Specifically, for example, 0 0 C C CF, CF. CFsCFzCFzOCFCOOCCFOCFtChC
Fx11 00 etc. The amount of these polymerization initiators used is 0.00 molar ratio to all monomers. It is preferable that it is 0 0 1 to 0.1.

As a polymerization condition, the polymerization temperature is approximately determined by the half-life temperature of the polymerization initiator used and the required polymerization rate, but is generally 0°C to 50°C, preferably 10°C to 30°C. The fluorine-containing divinyl ether compound or the mixture of the fluorine-containing divinyl ether compound and other monomers used in the present invention has good polymerizability, and the polymerization is almost completed within several hours to 10 hours in the above-mentioned temperature range.

In addition, the pressure during polymerization may normally be atmospheric pressure, but when using a low boiling point fluorine-containing divinyl ether compound or a monovinyl ether compound as a monomer copolymerizable with this, to prevent scattering due to evaporation. It is preferable to place the flat plates sandwiching these compounds in a pressure-resistant container and apply a pressure of several to 10 kg/1 with an inert gas such as nitrogen to polymerize.

Although the flat polymer plate after polymerization has sufficient mechanical strength, it is further treated at a temperature of 100°C to 150"C for several hours to remove trace amounts of unpolymerized material and reduce stress during polymerization. may be removed.

Prior to polymerization, fillers such as inorganic powders such as silica, alumina, and AJN; fibers such as glass, quartz, and polytetrafluoroethylene, and cloths thereof may be added for the purpose of improving mechanical strength.

Since the polymerization in the present invention is bulk polymerization for the purpose of molding, a mixture of monomers, a polymerization initiator, and optionally inorganic powder and fibers, or a fluid initial polymerization thereof, is placed between two flat plates. A flat polymer can be obtained by sandwiching the polymer between polymers and proceeding with polymerization. Also, when reinforcing with cross,
A cloth is sandwiched between two flat plates, and a mixture or an initial polymer is cast and polymerized to obtain a flat plate of polymer reinforced with cloth.

When used as a low dielectric circuit board, the thickness of the polymer layer constituting the laminate of the present invention is 0.00, taking into account the dielectric constant, etc.
It is preferable that it is 5n to 2 dragons.

The type and thickness of the metal constituting the laminate of the present invention are not particularly limited, but when the laminate of the present invention is used as a printed circuit board, copper or aluminum with a thickness of 0.1 μι to 50 μι is suitable. Further, it is preferable to use metal with one side roughened in order to improve adhesion to the polymer.

Any method can be used to manufacture the laminate. Usually, a method can be adopted in which a flat plate of polymer is made and metal is bonded using an adhesive.

When this method is adopted, it is desirable to use an adhesive that does not impair the properties of the laminate, especially the electrical properties.

In addition, since the polymer of the fluorine-containing divinyl ether compound represented by the general formula (1) has good adhesion to metals, a cloth may be inserted between two metal sheets if necessary, and a mixture of monomers or its By casting the initial polymer and further proceeding with polymerization, a laminate in which metals are laminated on both sides of a polymer flat plate can be obtained. Also, a laminate with metal layered on one side is also 1
It can be manufactured by placing a cloth on a sheet of metal if necessary, then casting a mixture of monomers or an initial polymerization thereof, and then sandwiching the mixture between flat plates for polymerization.

(Effects) Compared to the already developed laminate using polytetrafluoroethylene, the laminate obtained by the present invention has the same heat-resistant dielectric constant, but has poor adhesion to metals and dimensional stability. The laminate of the present invention is suitable for low dielectric circuit boards used in large-scale computers, etc. It can be used as a multilayer substrate.

(Examples) Examples are listed below, but the present invention is not limited to these examples.

Example 1 A lower plate made of stainless steel measuring 351 squares and having a circumferential wall measuring 5 squares in height and 25 squares in width, 30 cm square and 5 meters thick.
A polymerization reactor was used which consisted of an upper plate that could be fitted into a recess in the lower plate with a gap of about 1 fi between the lower plate and the peripheral wall.

With the lower plate of the polymerization reactor horizontal, a sheet of copper foil (LP foil manufactured by Nikko Glude Foil Co., Ltd.) with a thickness of 35 μm is smoothed out and laid on top of it, along the periphery with a width of 1 mm and a thickness of 100 μm. /
I put in a spacer of volitetrafluoroethylene from j+++. Then CF t = CFOCF ztp 20
CP=CFt 1 5 g SCh=CFOCFzC
5 g of hCh and 0.0 g as a polymerization initiator. 2 2 g of C
A mixture containing F 3CF zcOOccF zCF 3 was cast. After smoothing out the wrinkles, I placed another piece of copper foil and closed the top plate. Next, the polymerization reactor was placed horizontally in a pressure vessel, the pressure vessel was pressurized to 51 g/ad with nitrogen, and polymerization was carried out at a temperature of 15° C. for 5 hours. Thereafter, the polymerization reactor was taken out from the pressure container and the polymer was taken out, and a laminate with a thickness of about 100 μl was obtained.

Example 2 Ch.
=CFOChChOCF=CFz 1 3 g 1C
h = CFOCHzChCh 7 g and ChCF as polymerization initiator! ChCOOCCF, CF. Ch O.
1100 laminates were made using 9 g of the mixture. However, in this example, a 28cm square glass cloth (manufactured by Unitika) was used for reinforcement.
UFT 104J) was placed in the spacer and polymerization was carried out.

The polymerization temperature was 20°C for 10 hours.

A laminate reinforced with a glass cloth approximately 100 μm thick with copper foil on both sides was obtained.

Example 3 CFz ”'CFOCF2CF2CF3 8 g 1C
F 3 CF 3 CF2=CFOCH2CFOChCFZOCFCH20
70 g of CF=Ch and a polymerization initiator were placed in a 100 cc flask equipped with a stirrer and a cooling tube, and after purging the flask space with nitrogen, the mixture was heated at 25°C for 1 hour.
Time polymerization was performed. The contents were a transparent liquid, and the viscosity was 30 cp when measured.

Using about 70 g of the obtained initial polymer, a laminate was produced by the apparatus method of Example 1, except that the polytetrafluoroethylene spacer used in Example 1 was changed to 300 μm.

The pressure in the pressure container was 5 kg/cd, and the polymerization temperature was 2.
Polymerized at 0℃ for 8 hours, with copper foil on both sides, about 300mm thick
A μ-laminate was obtained.

Example 4 CFz=CFOChCFzOCP=Ch 7 g 1c
p, CF. CFz = CFOCHzCFOCFzCFzOCFCT
oOCF = CF2 1 4 g 1 Except for using a mixture of silica Ig as a polymerization initiator, using a 50 μm thick aluminum foil instead of copper foil for the laminate, and using a polytetrafluoroethylene spacer. Example 1
Manufactured using the same equipment and method. The nitrogen pressure in the pressure vessel is 1
kg/all, and polymerized for 3 hours at a polymerization temperature of 15° C. to obtain a laminate having aluminum foil on both sides and having a thickness of about 1 mm.

Example 5 CFz = CFOCHz (CFz) 4cHzOcF
= CFz 2 0 g 1CF2 = CFOCHz
CF2CFzCFzCh 5 g and CF+CFzCh
COOCCFzChCF+ 0. A mixed solution containing 1100 g was polymerized at 20° C. for 8 hours using the apparatus and method of Example 1 to obtain a laminate having a thickness of about 100 μm and having copper foil on one side.

Example 6 CFz=CFOChCF+ 3 g, CF+CFz
ChCOOCChChCh11 00 0. Using 1 g of the mixture, polymerization was carried out at 20° C. for 5 hours using the apparatus and method of Example 1 to obtain a laminate having a thickness of about 100 μm and having tAM on both sides.

Example 7 The electrical properties, thermal properties, and adhesive strength of the laminates obtained in Examples 1 to 6 were measured. The results are shown in the table below.

Example 8 Example 1 in which metal foil was removed to examine drill workability
copolymer and a 0.5 day thick polytetrafluoroethylene plate using a drill with a diameter of 1, and heated at 600 rpm+ at room temperature.
Holes were drilled using a scanning electron microscope, and the condition of each hole was examined using a scanning electron microscope.

As a result, bulges were observed around the holes in the polytetrafluoroethylene board, the flatness of the board was lost, and resin remained in the form of streaks inside the holes, but the copolymer of Example 1 The flatness was maintained, and the inside of the hole was also clean.

Claims (1)

[Claims] (1) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [However, j and k are each 0 or 1, and l and m
are each an integer of 0 or more, n is an integer of 2 or more,
When k is 1, j, l and m are all 0. ] A laminate formed by laminating a homopolymer or copolymer of a fluorine-containing divinyl ether compound represented by the following formula and a metal.