JPH11157009A - Manufacture of metal foil-clad laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of a metal foil-clad laminated sheet, in which the rate of dimensional change and its scattering are small and the accuracy of a sheet thickness is favorable. SOLUTION: In a metal foil-clad laminated sheet, which is produced by piling-up a required number of prepregs, each of which is obtained by impregnating a glass woven fabric with a resin for a laminating sheet and then drying the fabric, under the condition that a metal foil is placed on one side or both the sides of the piled-up prepregs so as to pressurize the piled-up prepregs under heat in order to obtain a metal foil-clad laminating sheet, a prepreg, the resin flow of which is 0.5-3.0% when measured with a method written in IPC TM-6502, 3, 17, is employed. The preferable glass woven fabric to be used has the ratio between thread counts per 25 mm (warp thread count/woof thread count) of 1.0-1.2 and the thermal expansion coefficient of 3×10<-6> / deg.C or less. The preferable metal foil to be used has a hot elongation at 180 deg.C of 10-50 %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal foil-clad laminate having a small dimensional change and a small variation in the dimensional change and a good thickness accuracy.

[0002]

2. Description of the Related Art A printed wiring board is manufactured by subjecting a metal foil-clad laminate to circuit processing and the like.
It is manufactured by laminating a plurality of prepregs obtained by impregnating a base material with a thermosetting resin varnish and drying and a metal foil, and applying heat and pressure. As the base material, paper, woven fabric of glass fiber, nonwoven fabric of glass fiber, or the like is used depending on the application.

[0003] With the miniaturization and high integration of electronic equipment, the circuit formation of printed wiring boards has also been miniaturized.
As circuit miniaturization progresses, dimensional changes and their variations cause
It is difficult to design when forming a multilayer, and a defect occurs due to a positional shift after the multilayer. On the other hand, as shown in JP-A-59-64350 and JP-B-05-57752, aging is performed after molding of a metal foil-clad laminate, and a metal foil and a fiber base material are specified. Thus, a method of reducing the dimensional change rate and its variation has been proposed.

[0004] Further, as a problem in manufacturing the metal foil-clad laminate, there is a variation in the plate thickness due to a difference in a production lot or a product position. On the other hand, Japanese Patent Publication No. 01-7519 discloses a method of improving the thickness accuracy by specifying the prepreg performance near a hot plate.

[0005]

However, the metal foil-clad laminates proposed in Japanese Patent Application Laid-Open No. 59-64350 and Japanese Patent Publication No. 05-57752 may be subjected to aging after molding, or to metal foil and fiber. The method of reducing the dimensional change rate and its variation by specifying the base material causes an increase in the number of manufacturing steps and is greatly influenced by the characteristics of the resin varnish used for the prepreg. Also, in the method proposed in Japanese Patent Publication No. 01-7519 to improve the thickness accuracy by specifying the prepreg performance near the hot plate, it is necessary to distinguish the prepreg performance between the vicinity of the hot plate and the center. This may cause a reduction in efficiency during prepreg production and prepreg loading.

The present invention has been made in view of the above problems, and in a method for manufacturing a metal foil-clad laminate, a metal foil-clad laminate having a small dimensional change rate and its variation and having good thickness accuracy is obtained. To provide a method for manufacturing a metal foil-clad laminate for use in the present invention.

[0007]

According to the present invention, a required number of prepregs obtained by impregnating a glass woven fabric with a resin for a laminate and drying are stacked, and a metal foil is placed on one or both surfaces thereof, and heated and pressed. In the metal foil-clad laminate obtained by this, the resin flow of the prepreg (IPC TM-650 2.3.1)
7) is a method for producing a metal foil-clad laminate using a prepreg of 0.5% to 3.0%. And it is the manufacturing method of the metal foil-clad laminated board whose glass woven fabric is a glass woven fabric in which the ratio of the number of driving per 25 mm is (number of warp yarns / number of weft yarns) = 1.0 to 1.2. Further, the glass woven fabric has a coefficient of thermal expansion of 3 × 10 ⁻⁶ /
This is a method for producing a metal foil-clad laminate that is preferably a glass woven fabric having a temperature of not more than ° C. Furthermore, it is a preferable method for producing a metal foil-clad laminate using a metal foil having a hot elongation at 180 ° C. of 10 to 50% as the metal foil.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The first invention of the present invention is to lay a required number of prepregs obtained by impregnating a glass woven fabric with a resin for a laminate and drying the resin, placing a metal foil on one or both surfaces thereof,
In a metal foil-clad laminate obtained by heating and pressing, the resin flow of the prepreg is IPC TM-650 2.3.
17. The measurement method according to item 17, wherein the content is 0.5% to 3.0%. When the resin flow of the prepreg is less than 3.0%, it is possible to suppress the flow of the resin, suppress distortion during heating and pressurizing, and reduce the dimensional change rate and its variation. Further, since the flow of the resin is small, the thickness at the end of the product is not reduced, and the accuracy of the thickness can be improved. However, when the resin flow is less than 0.5%, when the metal foil-clad laminate is obtained by heating and pressurizing, the base material tends to be blurred or voided.

In a second aspect of the present invention, there is provided the glass woven fabric according to the first aspect, wherein the ratio of the number of the woven fabrics per 25 mm (the number of warp yarns / the number of weft yarns) = 1.0 to 1.2. It was done. It is preferable to use a glass woven fabric having a ratio of the number of shots per 25 mm of 1.0 to 1.2, because the dimensional change rate can be further reduced. If the ratio of the number of shots per 25 mm of the glass woven fabric is less than 1.0, the difference in the dimensional change rate between the vertical direction and the horizontal direction becomes large. Further, even if this ratio exceeds 1.2, the difference in the dimensional change rate between the vertical direction and the horizontal direction will increase.

According to a third aspect of the present invention, in the first or second aspect, the glass woven fabric has a thermal expansion coefficient of 3 ×.
It is a glass woven fabric of 10 ⁻⁶ / ° C. or less. It is preferable to use a glass woven fabric having a coefficient of thermal expansion of 3 × 10 ⁻⁶ / ° C. or less as a base material because the dimensional change rate can be further reduced.

[0011] The fourth invention of the present invention is the first and second aspects of the present invention.
Alternatively, in the invention according to claim 3, the metal foil has a hot elongation at 180 ° C. (hereinafter, simply referred to as a hot elongation) of 10%.
〜50% of metal foil. By using a metal foil having a hot elongation of 10% or more as a metal foil, it is possible to suppress distortion generated between the resin base material and the metal foil when heating and pressing, and to further reduce the dimensional change rate. become able to. However, if the hot elongation exceeds 50%, the handleability is poor, and it is necessary to handle it very carefully, since it is likely to be broken and wrinkled when laminated.
As a result, the number of manufacturing steps is increased. Incidentally, the hot elongation rate, a rectangular test piece was cut from the metal foil to be measured, and the temperature of the test piece was set to 180 ° C. and pulled by a tensile tester.
The elongation at break of the test piece is expressed in%.

Examples of the thermosetting resin used for forming a prepreg include epoxy resins, polyimide resins, unsaturated polyester resins, and bismaleimide-triazine resins, which are conventionally used for laminated boards. Is mentioned. As a solvent used when these thermosetting resins are formed into a varnish, conventionally known solvents can be used.

[0013] The resin flow of the prepreg is changed to IPC TM-6.
50 According to the measurement method described in 2.3.17, 0.5% to
Examples of the method and conditions for producing 3.0% include a method of increasing the degree of curing of the B stage of the prepreg, a method of imparting thixotropy by introducing a filler, and a method of increasing the viscosity by blending a polymer resin. However, there is no particular limitation as long as the prepreg can be obtained.

[0014] The glass woven fabric may have a ratio of the number of shots per 25 mm of 1.0 to 1.2, and the yarn to be used is not particularly limited. Also, the woven fabric may be a plain weave,
There is no particular limitation on the loom for weaving. Furthermore, in order to improve the affinity with the thermosetting resin, it is preferable to perform treatment with a coupling agent such as a silane coupling agent. As a glass woven fabric having a thermal expansion coefficient of 3 × 10 ⁻⁶ / ° C. or less, an S glass woven fabric (thermal expansion coefficient = 2.8 × 1)
0 ^-6 / ° C).

As a metal foil used for obtaining a metal foil-clad laminate, a copper foil is usually used. Hot elongation 10
% To 50%, for example, HTE foil from Mitsui Kinzoku Kogyo Co., Ltd., HGR foil and M
A copper foil commercially available under the trade name of GR foil may be used.

The method and conditions for producing a metal-foil-clad laminate from a prepreg and a metal foil can be the same methods and conditions as in the prior art. That is, the number of sheets corresponding to the thickness of the metal foil-clad laminate for which the prepreg is to be manufactured is stacked, the metal foil is stacked on the outside (usually both sides), sandwiched by a stainless steel end plate or the like, and heated and pressed to form a metal sheet. Obtain a foil-clad laminate.

The metal foil-clad laminate manufactured by the manufacturing method of the present invention is also suitable as an inner layer of a multilayer printed wiring board. That is, circuit processing is performed on the metal foil-clad laminate manufactured by the manufacturing method of the present invention to form an inner layer board. Further, the single-sided metal foil-clad laminate can be used as an outer layer of a multilayer printed wiring board by the production method of the present invention.
When manufacturing these multilayer printed wiring boards, the prepreg used in the manufacturing method of the present invention is used as an adhesive prepreg to reduce dimensional changes and variations in the multilayer printed wiring boards and to improve the thickness accuracy. Is preferred. However, it is necessary to find out the optimum multilayering conditions under the conventionally known method conditions in consideration of the circuit filling property in the press at the time of multilayering using the adhesive prepreg.

When heating and pressurizing the prepreg, the resin varnish in the B-stage used for the prepreg is cured after melting. At that time, the molten resin varnish flows by pressure molding. Then, the flow of the resin causes the fiber base material to be pulled, and the cured laminate is left with strain, and this strain causes the dimensional change rate and its variation to deteriorate. Therefore, in the present invention, the dimensional change rate and its variation are reduced by setting the resin flow to 0.5% to 3.0% by the measuring method described in IPC TM-650 2.3.17. . Also, if the resin flow is large, heating and
At the time of pressure molding, the resin at the edge of the laminated sheet exudes to portions other than the product, resulting in a reduced thickness. Therefore, this phenomenon can be suppressed by reducing the resin flow, which is also effective for improving the thickness accuracy.

When the ratio of the number of the woven glass fabrics to be driven is (number of warp yarns / number of weft yarns) = 1.0 to 1.2, the anisotropy of the dimensional change rate is eliminated by eliminating the anisotropy of the glass woven fabric. Can be reduced. Further, for example, JIS R-3413
The ratio of the number of driving yarns per 25 mm to the number of warp yarns per 25 mm is 1.25, and the weight per unit area is 48 g / m ² . A glass substrate and a glass substrate 2
When the ratio of the number of driving yarns per 5 mm is (the number of warp yarns / the number of weft yarns) = 1.17 and the weight per unit area is 58 g / m ² , when the prepreg having the same thickness is obtained, As a result, the occupancy of the glass substrate is increased, the flow of the resin is suppressed, and the distortion can be reduced. Therefore, it is effective in reducing the dimensional change rate and its variation.

The thermal expansion coefficient of the glass woven fabric is 3.0 × 1
When the temperature is 0 ^-6 / ° C or less, the expansion of the glass woven fabric due to heat is reduced, which has the effect of suppressing the flow of the resin and can reduce the dimensional change rate. Further, when a metal foil having a hot elongation of 10% to 50% is used, the distortion generated between the metal foil and the resin is reduced because the metal foil follows the flow of the resin at the time of heating and pressing. Become smaller. As a result, the dimensional change rate decreases.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a metal foil-clad laminate of the present invention will be specifically described. (Preparation of epoxy resin varnish) Bisphenol A novolak type epoxy resin (Epiclon N-865, Dainippon Ink and Chemicals, Inc., 100 parts by weight and 1)
-Cyanoethyl-2-ethyl-4-methylimidazole 0.5 part by weight was dissolved in 100 parts by weight of methyl ethyl ketone to obtain a resin varnish.

Example 1 JIS R-3 was applied to a glass substrate.
The ratio of the number of driving yarns per 25 mm to the glass yarn having a designation of D450 1/0 specified in 413 is 25 (the number of warp yarns / the number of weft yarns) = 1.25, and the weight per unit area is 48 g / m ^2. And the thermal expansion coefficient is 5.0 ×
Using a plain-woven glass woven fabric of 10 ⁻⁶ / ° C. as a substrate, the resin flow was 2.0% according to the measurement method described in IPC TM-650 2.3.17, and the resin content was 58% after drying. The prepreg was impregnated so as to obtain a prepreg having a thickness of 0.06 mm. Thickness 1 on both sides of the obtained prepreg
8μm, 1.7% hot elongation of copper foil layered, under reduced pressure,
The copper-clad laminate 1 was obtained by heating and pressing at 175 ° C. and a pressure of 3 MPa for 60 minutes.

(Example 2) The ratio of the number of fibers driven per 25 mm of the glass substrate is (number of warp yarns / number of weft yarns) =
1.17, and the weight per unit area is 58 g / m ^2.
A copper clad laminate 2 was obtained under the same method conditions as in Example 1 except that the resin content of the obtained prepreg was 52% by weight after drying.

Example 3 A copper-clad laminate 3 was obtained under the same conditions as in Example 1 except that the glass substrate had a coefficient of thermal expansion of 2.8 × 10 ⁻⁶ / ° C.

Example 4 The hot elongation of the copper foil was 30.4.
% Copper foil (HTE-18, Mitsui Kinzoku Kogyo Co., Ltd., trade name), and a copper-clad laminate was obtained under the same method conditions as in Example 1.

(Comparative Example 1) JIS R-3 was used as a glass substrate.
The ratio of the number of driving yarns per 25 mm to the glass yarn having a designation of D450 1/0 specified in 413 is 25 (the number of warp yarns / the number of weft yarns) = 1.25, and the weight per unit area is 48 g / m ^2. And the thermal expansion coefficient is 5.0 ×
Using a plain-woven glass woven fabric of 10 ⁻⁶ / ° C. as a substrate, the resin flow was 10.0% according to the measurement method described in IPC TM-650 2.3.17, and the resin content was 58% after drying.
Impregnated to a weight% and dried to a thickness of 0.06 mm
A copper-clad laminate 4 was obtained under the same method conditions as in Example 1 except that the prepreg was obtained.

With respect to the copper-clad laminate manufactured as described above, the step change rate, its variation, and the thickness accuracy were examined as described below, and the results are shown in Table 1.

Dimensional change rate (based on JIS C-6481 "Test method for copper-clad laminate for printed wiring boards"): A test piece having a length of 300 mm and a width of 300 mm is cut out from the copper-clad laminate, and the four corners are standardized. Add a mark. 2 test pieces
After leaving for 24 hours in a room at 0 ° C. and a relative humidity of 60 to 70%, the distance between the reference marks in the length and width directions was measured, and
_Set to ₀ . Next, the entire surface of the copper foil of the test piece was etched, washed, dried, and then dried at 80 ° C. for 15 minutes.
And it left relative humidity 60% to 70% of the 11 indoors hours, further temperature 170 ° C. to hold for 30 minutes, cooled to room temperature, measuring the reference mark spacing length and width direction, which was the L _1, Equation 1 It is calculated by:

[0029]

Dimension change rate = (L ₀ −L ₁ ) × 100 / L ₀

Variation in dimensional change rate: The difference between the small value L (MAX) and the minimum value L (MIN) of the dimensional change rate calculated by the above-mentioned measuring method is calculated by equation 2.

[0031]

## EQU2 ## Variation of dimensional change rate = L (MAX) -L (MIN)

Thickness accuracy: A test piece similar to that used for the dimensional change rate was etched over the entire surface, and 8 parts around the test piece were etched.
The thickness of the point was measured, and 3σ (σ; standard deviation) was calculated from the measurement result at that time.

[0033]

[Table 1] Dimensional change rate (%) Dimensional change rate variation (%) Sheet thickness accuracy Vertical direction Vertical direction Vertical direction Horizontal direction (3σ) Example 1 -0.029 -0.074 0.017 0.028 0.006 Example 2 -0.015 -0.037 0.010 0.015 0.006 Example 3 -0.017 -0.058 0.016 0.027 0.006 Example 4 -0.018 -0.059 0.016 0.026 0.006 Comparative example -0.055 -0.109 0.031 0.043 0.012

Table 1 shows that, in Example 1, the dimensional change rate and its variation are extremely small as compared with the comparative example, and the plate thickness accuracy is also good. Further, in the second embodiment using the glass base material in which the ratio of the number of driving per 25 mm of the glass base material (the number of the warp yarns / the number of the weft yarns) = 1.17, the dimensional change rate and the variation thereof are further lower than in the first embodiment. Example 3 shows that it is smaller and has a coefficient of thermal expansion of 2.8 × 10 ⁻⁶ / ° C. Example 3 using a woven glass fabric, Example using a copper foil having a hot elongation of 30.4% 4 also shows that the dimensional change rate is smaller than in Example 1.

[0035]

According to the first aspect of the present invention, it is possible to manufacture a metal foil-clad laminate having a small dimensional change rate and its variation and a good thickness accuracy, and according to the second aspect of the present invention. It is possible to manufacture a metal-foil-clad laminate having a smaller dimensional change and a smaller variation than in the first embodiment. Furthermore, according to the third or fourth aspect of the invention, it is possible to manufacture a metal foil-clad laminate having a smaller dimensional change rate than the first aspect of the invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // H05K 1/03 610 H05K 1/03 610G

Claims (4)

[Claims] 1. A metal foil-clad laminate obtained by impregnating a glass woven fabric with a resin for a laminate, drying a required number of prepregs, placing a metal foil on one or both surfaces thereof, and heating and pressing the metal foil. In the board, the resin flow of prepreg (IPC
Measurement method described in TM-6502.3.17)
A method for producing a metal foil-clad laminate, comprising using a prepreg of 5% to 3.0%. 2. The glass woven fabric according to claim 1, wherein the ratio of the number of driving yarns per 25 mm is (number of warp yarns / number of weft yarns) = 1.0 to 1.0.
The method for producing a metal foil-clad laminate according to claim 1, which is a glass woven fabric of 1.2. 3. The glass woven fabric has a coefficient of thermal expansion of 3 × 10 ^−6.
The method for producing a metal-foil-clad laminate according to claim 1 or 2, which is a glass woven fabric having a temperature of not more than / ° C. 4. The metal foil having a hot elongation at 180 ° C. of 10 to 50%.
The method for producing a metal foil-clad laminate according to any one of the above.