JP2001030279A - Manufacture of laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminated sheet, by which the dimensional stability of the laminated sheet is high through the checking of the accumulation of an internal stress to the laminated sheet during the heating and cooling process in molding and the development of warpage and twisting in the laminated sheet is checked. SOLUTION: In the manufacturing method of a laminated sheet, in which a laminated matter is formed by laminating a plurality of sheets of prepreg made of a thermosetting resin composition and a base material to one another so as to be molded under heat and pressure to obtain a laminated sheet, a temperature region in which resin temperature exceeds the glass transition temperature of a set thermosetting resin composition, is set and, at the same time, a pressure region in which a mold pressure is 5 kg/cm2 or less, is set. As a result, the internal stress of the laminated sheet can be prevented from accumulating at its molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated board used for manufacturing a printed wiring board used for electric / electronic equipment and the like.

[0002]

2. Description of the Related Art Conventionally, a laminated board used for manufacturing a printed wiring board is obtained by impregnating a base material such as a glass cloth with a thermosetting resin composition such as an epoxy resin, and then drying and semi-curing. By preparing a prepreg, stacking the required number of prepregs, and arranging a metal foil such as a copper foil on one side or both sides as necessary to form a laminate, and by heating and pressing the laminate, Had been manufactured.

[0003] In the heat-press molding, the occurrence of defects such as voids and frays in the insulating layer of the laminate is suppressed, and the increase in the surface roughness of the laminate to be formed is suppressed. In order to improve moldability, a molding pressure of 10 kg / cm ² or more was applied.

[0004]

However, at the time of heating and pressurizing, the prepreg or the insulating layer formed by the prepreg expands at the time of heating due to the thermal expansion of the thermosetting resin composition, and at the time of cooling or the thermosetting resin. When the curing reaction of the composition progresses, the composition shrinks. When the molding pressure is set to 10 kg / cm ² or more, the dimensional change of the laminate at the time of heating and pressing is suppressed, and the prepreg is hardened. Alternatively, internal stress resulting from expansion and contraction of the insulating layer formed by the prepreg is accumulated in the laminate. When the laminated board in which such internal stress is accumulated is heated in a next step such as a screen printing step of a resist film for forming a printed wiring board, the internal stress is released, and the dimensions of the laminated board are reduced. They change, warp or twist, and cause dimensional errors and shape errors of products.

The present invention has been made in view of the above points, and suppresses the accumulation of internal stress in a laminate during the heating / cooling process during molding, has high dimensional stability, and is free from warpage and twist. It is an object of the present invention to provide a method for manufacturing a laminated board capable of producing a laminated board in which generation is suppressed.

[0006]

According to a first aspect of the present invention, there is provided a method for manufacturing a laminate, comprising: laminating a plurality of prepregs each comprising a thermosetting resin composition and a base material to form a laminate; In a method of manufacturing a laminate by heating and pressing a product,
During the heating and pressurizing process, a region where the resin temperature exceeds the glass transition temperature of the cured product of the thermosetting resin composition is set, and a region where the molding pressure is 5 kg / cm ² or less is set in this region. It is characterized by doing.

According to a second aspect of the present invention, there is provided a method for manufacturing a laminated board according to the first aspect, wherein the resin temperature is in a region where the resin temperature exceeds a glass transition temperature of the thermosetting resin composition. The pressing time in the region where the molding pressure is 5 kg / cm ² or less is 50 to 100% of the pressing time in the region where the heating temperature is higher than the glass transition temperature of the cured product of the thermosetting resin composition. It is characterized by the following.

According to a third aspect of the present invention, there is provided a method for manufacturing a laminated board according to the first or second aspect, wherein the temperature of the thermosetting resin composition is set to a minimum melt viscosity during the heating and pressing process. Is set from a temperature 20 ° C. lower than the temperature indicating the lowest melt viscosity to a temperature 20 ° C. higher than the temperature indicating the lowest melt viscosity, and the molding pressure in this region is set to 10 to 30 kg.
/ Cm ² .

According to a fourth aspect of the present invention, there is provided a method of manufacturing a laminated board according to any one of the first to third aspects, further comprising: A region where the temperature is lowered from a temperature exceeding the glass transition temperature of the product to a temperature lower than the glass transition temperature of the cured product of the thermosetting resin composition is set, and in this region, at least the region where the resin temperature exceeds the glass transition temperature. During the molding pressure is 1
It is characterized in that an area of 0 to 30 kg / cm ² is set.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a laminated board according to the fourth aspect, further comprising the steps of:
In a region where the resin temperature is lowered from a temperature exceeding the glass transition temperature of the cured product of the thermosetting resin composition to a temperature lower than the glass transition temperature of the cured product of the thermosetting resin composition, the resin temperature is not higher than the glass transition temperature. A region where the molding pressure is 10 to 30 kg / cm ² is also set in the region where

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a laminate according to the present invention will be described.

First, a prepreg that can be used in the present invention will be described.

As the base material, woven fabric, non-woven fabric, paper and the like made of inorganic fibers such as glass, organic fibers such as polyester, polyamide, polyacryl and polyimide, and natural fibers such as cotton can be used. A woven fabric (glass cloth) such as glass fiber is preferable because it has excellent heat resistance and moisture resistance, and the effects of the present invention can be easily obtained.

The thermosetting resin composition may be a thermosetting resin such as an epoxy resin, a phenol resin, a polyimide resin, an unsaturated polyester resin, a polyphenylene ether, etc., alone, modified or a mixture. The entire composition can be used.

The thermosetting resin composition contains a thermosetting resin as an essential component, and may contain a curing agent, a curing accelerator, an inorganic filler and the like of the thermosetting resin as required. it can. Note that a thermosetting resin composition having a low self-curing property, such as an epoxy resin, needs to contain a cured product or the like for curing the resin.

Here, when the thermosetting resin composition is an epoxy resin-based composition, the balance between the electrical properties and the adhesiveness is good, which is preferable. Examples of the epoxy resin that can be contained in the epoxy resin-based resin composition include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolak epoxy resin, and bisphenol A novolak epoxy resin. Halogenating some of the hydrogen atoms in these epoxy resin structures, such as bisphenol F novolak epoxy resin, cresol novolak epoxy resin, diaminodiphenylmethane epoxy resin, and brominated bisphenol A epoxy resin Epoxy resin which has been made flame-retardant. In the epoxy resin-based thermosetting resin composition, it is preferable to mix one or more of the above epoxy resins so that the halogen weight is 15 to 20% by weight based on the total amount of the resin.

Examples of the curing agent which can be contained in the epoxy resin-based resin composition include amide-based curing agents such as dicyandiamide and aliphatic polyamide; amine-based curing agents such as ammonia, triethylamine and diethylamine; Examples thereof include phenolic hardeners such as phenol novolak resin, cresol novolak resin, and p-xylene-novolak resin, and acid anhydrides. In the epoxy resin-based thermosetting resin composition, a mixture of one or more of the above curing agents,
It is preferable to contain 1.5 to 20% by weight.

As a curing accelerator, an imidazole compound or the like can be used. In particular, when 2-ethyl-4-methylimidazole (2E4MZ) is blended, curing of the resin composition during storage becomes difficult to proceed, and This is preferable in that the varnish life can be maintained and the varnish life can be maintained. The epoxy resin-based thermosetting resin composition preferably contains 2E4MZ in an amount of 0.01 to 0.05% by weight.

Examples of the inorganic filler that can be contained in the thermosetting resin composition include inorganic powder fillers such as silica, calcium carbonate, aluminum hydroxide, and talc; glass fibers, pulp fibers, and synthetic fibers. Examples include fibrous fillers such as ceramic fibers, and these inorganic fillers can be blended in the range of 10 to 80% by weight.

The method for producing the prepreg from the thermosetting resin composition and the base material is not particularly limited. For example, the base material may be converted into a resin varnish obtained by adjusting the viscosity of the thermosetting resin composition with a solvent. After being immersed and impregnated, it is obtained by heat-drying and semi-curing as necessary. For example, when using an epoxy resin-based thermosetting resin composition, it is 3 to 15 at 130 to 200 ° C. It can be heated and dried for minutes. Here, examples of the solvent that can be used for adjusting the viscosity of the thermosetting resin composition include amides such as N, N-dimethylformamide (DME) and ethers such as propylene glycol monobutyl ether (PC) and ethylene glycol monomethyl ether. And ketones such as acetone and methyl ethyl ketone (MEK); alcohols such as methanol and ethanol; aromatic hydrocarbons such as benzene and toluene; and mixtures of one or more of these solvents. Can be blended in the range of 5 to 40% by weight.

Here, the amount of resin in the prepreg is determined by the weight of the prepreg (the total weight of the thermosetting resin composition and the base material).
It is preferable that the amount be 40 to 70 parts by weight based on 100 parts by weight. When the amount is less than 40 parts by weight, bubbles may remain inside the substrate when the laminate is heated and pressed, and the electrical characteristics may be reduced. When the amount exceeds 70 parts by weight, the laminate may be heated and heated. When the resin is pressed, the resin flow is large, and the variation in the plate thickness may be large.

A method for manufacturing a laminate using the prepreg obtained as described above will be described. In the following, the term “resin temperature” refers to the temperature of the thermosetting resin composition during the heating and pressurizing process or the temperature of the cured product of the thermosetting resin composition, and the term “glass transition temperature” refers to the heat. When the glass transition temperature of the cured product of the curable resin composition is referred to as “minimum melt viscosity temperature”, it means the temperature at which the thermosetting resin composition exhibits the minimum melt viscosity.

First, a plurality of prepregs composed of the above-described thermosetting resin composition and a base material are laminated, and a metal foil is arranged on one or both sides thereof as required to form a laminate. Here, as metal foil, copper, aluminum, brass,
Single, alloy, or composite metal foils such as nickel can be used.Instead of metal foil, use a single-sided metal foil-clad laminate or a double-sided metal foil-clad laminate in which a metal foil is laminated and formed on an insulating resin layer. Can also. The thickness of the metal foil is 12 to
70 μm is common.

The heating and pressurization of the laminate can be performed by placing the laminate between hot plates and hot pressing. Further, the laminate may be arranged between the pressure plates to apply pressure, and at the same time, the metal foil constituting the laminate may be energized to heat the metal foil. The heating temperature at this time, that is, the temperature of the hot platen or the heating temperature of the metal foil is set to a temperature exceeding the glass transition temperature, and specifically, 130
It is preferable to set the temperature in the range of 200 to 200 ° C. At this time, the molding pressure on the laminate is changed in accordance with a change in the temperature of the resin in the laminate. That is, when the resin temperature is in a temperature range exceeding the glass transition temperature,
The region where the molding pressure on the laminate is 5 kg / cm ² or less is set. In this case, the internal stress in the laminated plate to be molded is reduced. The lower limit of the molding pressure at this time may be 0 kg / cm ² , that is, the pressure applied to the laminate by the hot plate may be 0 kg / cm ² .
Here, the time in the region where the molding pressure on the laminate is 5 kg / cm ² or less is preferably in the range of 50 to 100% of the time in the region where the resin temperature is in a temperature range exceeding the glass transition temperature. .

During the heating and pressurizing process, the resin is heated from a temperature lower by 20 ° C. than the lowest melt viscosity temperature to a temperature of 20 ° C. lower than the lowest melt viscosity temperature by heating the laminate.
It is preferable to set a region where the temperature is raised to a higher temperature, and to set the molding pressure in this region to a range of 10 to 30 kg / cm ² , and more preferably to set the molding pressure to 20 kg / cm ^2.
-30 kg / cm ² . By doing so, it is possible to eliminate the voids in the thermosetting resin composition and to re-impregnate the substrate with the thermosetting resin composition to the base material, and to reduce molding defects such as voids and frays in the laminate. This can improve the moldability by suppressing the occurrence.
Here, when using an epoxy resin composition as the thermosetting resin composition, the temperature higher by 20 ° C. than the lowest melt viscosity temperature is usually in the range of 150 to 160 ° C., and the heating temperature of the laminate at this time is 20 above the minimum melt viscosity temperature
The temperature is set to be higher than the temperature which is higher by only ° C.

In the process of cooling the laminate after stopping the heating of the laminate, a region where the resin temperature exceeds the glass transition temperature and the molding pressure is in the range of 10 to 30 kg / cm ² is set. Is preferred. In this way, the undulation of the substrate can be suppressed, and the thermosetting resin composition can be uniformly cured and shrunk, so that the surface roughness of the laminate can be reduced and the moldability can be improved. is there.
In the process of cooling the laminate, if the molding pressure is kept in the range of 10 to 30 kg / cm ² even in the region where the resin temperature is lower than the glass transition temperature, not only the viscosity region of the resin exceeding the glass transition temperature but also the glass Since the pressing is continued even in the elastic region of the resin having a transition temperature or lower, the surface roughness of the laminate can be further reduced.

FIG. 1 shows an example of the control of the molding pressure with respect to the resin temperature in the process of heating and pressing the laminate. In the heating and pressing molding process shown in this figure, after the heating of the laminate is started, the resin temperature is lower than the lowest melt viscosity temperature by 20%.
In the temperature range A, which is a temperature lower than the temperature lower by ° C.,
The molding pressure is first in the range of 5 to 10 kg / cm ² , and when the resin temperature approaches a temperature 20 ° C. lower than the minimum melt viscosity temperature Mp, the molding pressure is increased. When the pressure reaches 2
The range is 0 to 30 kg / cm ² . Next, in a temperature range B in which the resin temperature is raised from a temperature 20 ° C. lower than the minimum melt viscosity temperature Mp to a temperature 20 ° C. higher than the minimum melt viscosity temperature Mp, the molding pressure is set in the range of ²⁰ to 30 kg / cm ² . maintain. Next, the resin temperature is set to the minimum melt viscosity temperature Mp.
After the temperature exceeds 20 ° C. higher than that, in the temperature range C for a while, the molding pressure is continuously increased to 20 to 30 kg /
Maintain in the range of cm ² . Next, after the resin temperature further rises, the heating of the laminate is stopped, and the molding pressure is set to a range of 0 to 5 kg / cm ² in a temperature range D until the resin temperature starts to decrease and a while later. This temperature range D
Is the temperature range F where the resin temperature exceeds the glass transition temperature Tg.
The time is set in a range of 50% or more of the time in the temperature region F in which the resin temperature exceeds the glass transition temperature Tg. Here, the temperature region F includes the entire temperature region C and partially overlaps with the temperature region B. Next, in a region E in which the resin temperature further decreases and the resin temperature becomes a temperature equal to or lower than the glass transition temperature from a temperature exceeding the glass transition temperature Tg,
The molding pressure is in the range of 10 to 30 kg / cm ² .

Since the internal stress of the laminate formed through such a heating and pressurizing process is reduced, when the metal foil on the surface is removed by etching or when the laminate is heated to a temperature higher than the glass transition temperature. This also suppresses the occurrence of dimensional change and warpage, and also suppresses the occurrence of molding defects such as voids and blurring, thereby improving moldability.

[0029]

The present invention will be described below in detail with reference to examples.

(Examples 1 to 7, Comparative Example 1) As a thermosetting resin composition, a thermosetting resin composition comprising the following epoxy resin, curing agent and curing accelerator was used. Here, the temperature at which this thermosetting resin composition exhibits the minimum melt viscosity is 127.
° C, and the glass transition temperature of the cured product of the thermosetting resin composition is 137 ° C. Epoxy resin: 100 parts by weight of a tetrabromobisphenol A type epoxy resin having an epoxy resin equivalent of 500 [trade name: YDB-500, manufactured by Toto Kasei Co., Ltd.] Curing agent: 3 parts by weight of dicyandiamide. -Cure accelerator: 0.2 parts by weight of 2-ethyl-4-methylimidazole.

As a substrate, a glass cloth having a thickness of 0.19 mm and a width of 1 m [manufactured by Asahi Schwebel; 7628W
AS750S], the base material was impregnated by immersing the thermosetting resin composition in a resin varnish of which viscosity was adjusted by adding N, N-dimethylformamide (DME) as a solvent. By heating and drying at a temperature of 3 ° C. for 3 minutes, a prepreg having a resin amount in the range of 42 to 45% by weight was produced.

Eight prepregs thus prepared were superimposed, and a copper foil having a thickness of 18 μm was arranged on both outer sides to prepare a laminate. Further, this laminate was sandwiched between plate-shaped dies, and 14 stacks were sandwiched between hot plates of a molding press with kraft paper sandwiched therebetween, and were heated and pressed at a hot plate temperature of 180 ° C. Here, the molding pressure was controlled as shown in Table 1 for each of Examples and Comparative Examples in each of the temperature ranges A to E shown in FIG.

(Evaluation Test) Examples 1 to 7 and Comparative Example 1
After removing the copper foil on both sides of the double-sided copper-clad laminate having the dimensions of 250 mm × 250 mm obtained in
Voids and blurring were visually observed to evaluate the formability.

After the above-mentioned etching treatment, E-0.
A 5/170 treatment was performed, and the dimensional change rate and the amount of warpage / twist of the substrate were measured in accordance with JIS C6481. Here, for the dimensional change rate, 32 laminates were prepared as samples for each of the examples and comparative examples, and the dimensional change rates were measured for these samples to derive the range of the dimensional change rate.

The surface roughness of the double-sided copper-clad laminate was measured using a surface roughness meter manufactured by Tokyo Seimitsu.

As shown in Table 1, the results are shown in Examples 1-7.
As compared with Comparative Example 1, the dimensional change rate and the amount of warpage / twist were reduced. In Examples 1 to 7, particularly in Examples 1 to 5 and Example 7, the surface roughness of the laminate was reduced,
Particularly, in Examples 1 to 4, the moldability was improved.

[0037]

[Table 1]

[0038]

As described above, in the method for manufacturing a laminate according to the present invention, a laminate is formed by laminating a plurality of prepregs each comprising a thermosetting resin composition and a base material, and the laminate is heated and heated. In the method of manufacturing a laminate to be pressure-formed, during the heating and pressing process, a region where the resin temperature is higher than the glass transition temperature of the cured product of the thermosetting resin composition is set and the molding pressure is set in this region. The area is set to 5 to 0 kg / cm ² or less, which suppresses the accumulation of internal stress in the laminated plate during molding of the laminated plate, and ensures dimensional stability when subjected to etching or heat treatment. Nature,
In addition, it is possible to obtain a laminated board in which occurrence of warpage and twist is suppressed.

Further, according to the method for producing a laminate according to claim 2 of the present invention, in addition to the constitution of claim 1, the method for producing a laminate in a region where the resin temperature exceeds the glass transition temperature of the thermosetting resin composition, The pressing time in the region where the molding pressure is 5 kg / cm ² or less is 50 to 100% of the pressing time in the region where the heating temperature is higher than the glass transition temperature of the cured product of the thermosetting resin composition. It is possible to further suppress the accumulation of internal stress in the laminate during molding of the laminate.

According to a third aspect of the present invention, there is provided a method for manufacturing a laminate according to the first or second aspect, wherein the thermosetting resin composition has a minimum melt viscosity during the heating and pressing process. Is set from a temperature 20 ° C. lower than the temperature indicating the lowest melt viscosity to a temperature 20 ° C. higher than the temperature indicating the lowest melt viscosity, and the molding pressure in this region is set to 10 to 30 kg.
/ Cm ^2, which can suppress the occurrence of voids and debris in the laminate and improve the formability of the laminate.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a laminated board according to any one of the first to third aspects, further comprising: A region where the temperature is lowered from a temperature exceeding the glass transition temperature of the product to a temperature lower than the glass transition temperature of the cured product of the thermosetting resin composition is set, and in this region, at least the region where the resin temperature exceeds the glass transition temperature. During the molding pressure is 1
An area of 0 to 30 kg / cm ² is set, and a laminate having reduced surface roughness can be obtained.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a laminated board according to the fourth aspect, further comprising the steps of:
In a region where the resin temperature is lowered from a temperature exceeding the glass transition temperature of the cured product of the thermosetting resin composition to a temperature lower than the glass transition temperature of the cured product of the thermosetting resin composition, the resin temperature is not higher than the glass transition temperature. The region where the molding pressure is 10 to 30 kg / cm ² is also set in the region where the surface pressure is to be reduced, and the surface roughness of the laminate can be further reduced.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention,
4 is a graph showing a change in a molding pressure with respect to a resin temperature.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F204 AA36 AA39 AB03 AB19 AD16 AG03 AH36 AR02 AR06 AR11 FA01 FB01 FB22 FF01 FF06 FN15 FN17

Claims (5)

[Claims] 1. A method of manufacturing a laminate, comprising laminating a plurality of prepregs each comprising a thermosetting resin composition and a base material to form a laminate, and forming the laminate by heat and pressure. In addition, a region where the resin temperature exceeds the glass transition temperature of the cured product of the thermosetting resin composition is set, and a region where the molding pressure is 5 kg / cm ² or less is set in this region. Manufacturing method of the laminated plate to be performed. 2. The pressurizing time in the region where the molding pressure is 5 kg / cm ² or less in the region where the resin temperature exceeds the glass transition temperature of the thermosetting resin composition, 50 to 100% of the pressurization time in a region where the temperature exceeds the glass transition temperature of the cured product of the resin composition
The method for producing a laminated board according to claim 1, wherein the time is set to a predetermined time. 3. During the heating and pressurizing process, the resin temperature is raised from a temperature 20 ° C. lower than the temperature at which the thermosetting resin composition exhibits the lowest melt viscosity to a temperature 20 ° C. higher than the temperature at which the thermosetting resin composition exhibits the lowest melt viscosity. The method for producing a laminate according to claim 1, wherein a region to be formed is set, and a molding pressure in this region is set to 10 to 30 kg / cm ² . 4. The resin temperature is thermosetting at the time of heating and pressing
From a temperature above the glass transition temperature of the cured resin composition
Temperature below the glass transition temperature of the cured product of the thermosetting resin composition
Set the area to be cooled down to
At least in the region where the resin temperature exceeds the glass transition temperature
Inside, the molding pressure is 10-30kg / cm ²Area
4. The method according to claim 1, wherein the setting is performed.
The method for producing a laminate according to the above. 5. The method according to claim 1, wherein the temperature of the resin is lowered from a temperature higher than the glass transition temperature of the cured product of the thermosetting resin composition to a temperature lower than the glass transition temperature of the cured product of the thermosetting resin composition during the heat and pressure molding. In the region where the resin temperature is equal to or lower than the glass transition temperature, the molding pressure is 10 to 30 kg /
5. An area having a size of cm ² is set.
5. The method for producing a laminate according to item 1.