JPH05271442A - Production of laminate board - Google Patents

Abstract

PURPOSE:To produce a laminate board which is suitable as a printed circuit board compatible with an SMD and has a low elastic modulus to improve the reliability of soldered joint of the SMD while assuring the heat resistance. moisture resistance, and strength of peeling from a metal foil, the properties formerly lowered when the elastic modulus is lowered. CONSTITUTION:As the surface layer of a laminate board is used a prepreg produced by pretreating glass fabric with a resin mixture of 20-90wt.% epoxy resin modified by a dimer acid with 80-10wt.% epoxy resin based on a propylene oxide adduct of bisphenol A, then impregnating the fabric with a thermosetting resin, and drying it. The amt. of the resin mixture deposited on the fabric is adjusted to 30wt.% or lower of the fabric.

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 suitable as a substrate for a printed wiring board on which surface mount components (hereinafter referred to as "SMD") are mounted.

[0002]

2. Description of the Related Art With the recent trend toward higher density, higher integration and smaller size of electronic and electrical equipment, the components mounted on a printed wiring board to be incorporated therein are also changed from insertion components to surface mount SMDs. It is transitioning. What must be noted as an SMD-compatible printed wiring board is the problem of reliability of the solder connection portion between the SMD and the printed wiring. That is,
The coefficient of thermal expansion in the plane direction of the laminated board which is the substrate of the printed wiring is considerably larger than the coefficient of thermal expansion of SMD (the coefficient of thermal expansion of SMD = 4 to 6 ppm, the coefficient of thermal expansion of the substrate = 15 to
25 ppm). Therefore, when the cooling / heating cycle is repeated, the stress resulting from the difference in the coefficient of thermal expansion acts on the solder connection portion each time, and the solder connection portion is likely to be cracked. Therefore, by lowering the elastic modulus in the plane direction of the laminated plate, which is the substrate material of the printed wiring board, the stress due to the difference in the thermal expansion coefficient between the SMD and the substrate is relaxed by the low elastic substrate, and It is considered to prevent large stress from working. The laminated plate is manufactured by impregnating a sheet-shaped base material with a thermosetting resin which is a matrix resin, and stacking and heat-pressing the base material. For example, a flexibility-imparting agent is simply added to the matrix resin. Alternatively, a technique for reducing the elastic modulus by reacting the added flexibility-imparting agent with a matrix resin or a curing agent has been studied. Further, in the case of containing an inorganic filler, the atomization or spheroidization of the inorganic filler has been studied.

[0003]

However, although the conventional technique for lowering the elastic modulus can reduce the elastic modulus of the laminated board, another characteristic required for the substrate of the printed wiring board, that is, heat resistance, is required. There is a problem in that the peelability and the peeling strength of the metal foil are reduced. The problem to be solved by the present invention is, as a laminated board suitable for a substrate of an SMD-compatible printed wiring board, a low elastic modulus necessary for ensuring solder connection reliability, as well as heat resistance, insulation, and metal. It is to secure the foil peeling strength.

[0004]

In order to solve the above-mentioned problems, the first production method according to the present invention is to impregnate a sheet-like base material made of glass fiber with a thermosetting resin, and stack and heat the same. In the production of a laminated plate to be pressure-molded, and in the production of a laminated plate in which the sheet-shaped base material of the surface layer is made of glass woven fabric, at least the sheet-shaped base material arranged in the surface layer is impregnated with the thermosetting resin. First, the following preliminary processing is performed. That is, dimer acid-modified epoxy resin (A) and propylene oxide-added bisphenol A type epoxy resin (B)
The sheet-shaped base material is pretreated with the combination composition of (1) and (A) / (B) =
It is characterized in that it is 20/80 to 90/10 and the amount of adhesion to the sheet-shaped substrate is 30% by weight or less. The second production method according to the present invention is the same as the first production method, except that the amount of the combined composition of the dimer acid-modified epoxy resin and the propylene oxide-added bisphenol A type epoxy resin attached to the sheet-like substrate is preferably 10 or less. ~ 30% by weight
And A third production method according to the present invention is characterized in that, in the first or second production method, the dimer acid-modified epoxy resin is preliminarily reacted with a novolac type phenol resin.

A fourth manufacturing method according to the present invention comprises impregnating a sheet-like base material made of glass fiber with a thermosetting resin,
In the manufacture of a laminated plate in which the sheet-like base material of the surface layer is laminated by heating and pressurizing, and in the manufacture of a laminated plate in which the sheet-like base material of the surface layer is made of glass woven As the resin, a dimer acid-modified epoxy resin (A) and a propylene oxide-added bisphenol A type epoxy resin (B) in a solid weight ratio of (A) / (B)
= 20/80 to 90/10, and is mixed in an amount of 40 parts or less with respect to 100 parts by weight of the thermosetting resin. The 5th manufacturing method which concerns on this invention WHEREIN: The compounding quantity of the combination composition of a dimer acid-modified epoxy resin and a propylene oxide addition bisphenol A type epoxy resin in the said 4th manufacturing method is preferably the solid content of the said thermosetting resin. It is 20 to 40 parts per 100 parts of the mold weight. A sixth manufacturing method according to the present invention is the above-mentioned fourth or fifth manufacturing method,
The dimer acid-modified epoxy resin is characterized by being preliminarily reacted with a novolac type phenol resin.

[0006]

In the method according to the present invention, a dimer acid-modified epoxy resin and propylene oxide-added bisphenol A are added.
By using a type epoxy resin in combination, a low elastic modulus is achieved without deteriorating the characteristics required for a printed wiring board.
As an SMD-compatible substrate, the reliability of solder connection is ensured. Since the dimer acid-modified epoxy resin has an aliphatic skeleton, when it is used alone by mixing it with a thermosetting resin, the heat resistance of the laminate and the metal foil integrally attached to the surface during molding of the laminate Will reduce the adhesive strength of. Therefore, propylene oxide-added bisphenol A type epoxy resin is also used in combination to suppress the decrease in heat resistance and the adhesive force of the metal foil. However, dimer acid-modified epoxy resin (A)
The use ratio of propylene oxide-added bisphenol A type epoxy resin (B) is (A) / solid type weight ratio.
(B) = 20/80 to 90/10. When the proportion of (A) is small and the proportion of (B) is large, the moisture-proof insulating property of the laminate is deteriorated due to the influence of the ether bond of (B).
When the proportion of (A) is high and the proportion of (B) is low, heat resistance and adhesive strength of the metal foil are reduced. If the amount of the combined composition of (A) and (B) used is too large, the heat resistance of the laminate is lowered. Therefore, the amount of the composition to be adhered to the sheet-shaped substrate within the above range or to the thermosetting resin The blending amount of further,
The lower limit of the amount of the combined composition of (A) and (B) used is within the above-mentioned range (adhesion amount to the sheet-like substrate: 10% by weight or more, or 20 to 100 parts by weight of thermosetting resin solid type). It becomes more suitable for SMD use. In addition, by using the dimer acid-modified epoxy resin after pre-reacting with the novolac-type phenol resin, the unreacted dimer acid-modified epoxy resin can be reduced, and the heat resistance of the laminate and the adhesive strength of the metal foil can be reduced. The effect of suppressing the deterioration becomes large. Furthermore, the low-elasticity dimer acid-modified epoxy resin and propylene oxide-added bisphenol A type epoxy resin are present at the interface between the thermosetting resin and the sheet-shaped substrate or in the thermosetting resin, so that the thermosetting resin Absorbs and relaxes the internal stress of the laminated plate caused by the curing shrinkage of Due to such an action, it is possible to have an effect of suppressing the warp / twist of the laminated plate which has been conventionally caused by the internal stress.

[0007]

EXAMPLES Sheet-like substrates made of glass fibers used in the method according to the present invention are glass woven cloth, glass nonwoven cloth, glass-paper mixed nonwoven cloth and the like. Further, as the thermosetting resin, an epoxy resin, a phenol resin, a urea resin, a polyimide, a polyester or the like can be appropriately used. These thermosetting resins include inorganic fillers (Al ₂ O ₃ , Al ₂ O ₃ · H) for the purpose of quality improvement, processability improvement, and cost reduction.
₂ O, Al ₂ O ₃ .3H ₂ O, talc, MgO, SiO ₂ etc.) may be blended. The dimer acid-modified epoxy resin used in the method according to the present invention has a chemical structural formula as shown in Chemical formula 1, or a pre-reacted product of the dimer acid-modified epoxy resin and a novolak type phenol resin. The novolac type phenolic resin is obtained by reacting phenols such as phenol, alkylphenol and dihydric phenol with formaldehyde under an acidic catalyst. The propylene oxide-added bisphenol A type epoxy resin used in the method according to the present invention has a chemical structural formula as shown in Chemical formula 2.

[0008]

[Chemical 1]

[0009]

[Chemical 2]

The laminate produced by the method according to the present invention may be either a composite type in which the sheet-shaped substrate is a combination of a glass woven fabric and a glass nonwoven fabric, or a type of a laminate made of a glass woven fabric alone. It also includes a laminated board for a multilayer printed wiring board.

Examples 1 to 6 and Comparative Examples 1 to 3 (Preparation of varnish A for pretreatment) Dimer acid-modified epoxy resin (Toto Kasei, YD-172) and propylene oxide-added bisphenol A type epoxy resin (Sanyo Kasei) , BPP-350) was dissolved in dilute solvent methyl ethyl ketone in the blending amounts shown in Table 1, dicyandiamide was added to the curing agent, and 2-ethyl-4-methylimidazole was added to the curing accelerator to prepare varnish A. (Preparation of varnish A'for pretreatment) 20 parts by weight of novolac type phenol resin (Dainippon Ink and Briofen VH-4170) per 35 parts by weight of dimer acid-modified epoxy resin (Toto Kasei, YD-172). Parts, 0.5 parts by weight of a curing accelerator 2-ethyl-4-methylimidazole, and 30 parts by weight of methyl ethyl ketone as a diluting solvent, and a dimer acid-modified epoxy resin / novolak type resin at 80 ° C. for 5 hours. A phenolic resin pre-reactant was prepared. Then, the preliminary reaction product and propylene oxide-added bisphenol A type epoxy resin (manufactured by Sanyo Kasei Co., Ltd., B
PP-350) was dissolved in a diluting solvent methyl ethyl ketone in a blending amount shown in Table 1, dicyandiamide was added as a curing agent, and 2-ethyl-4-methylimidazole was added as a curing accelerator to prepare a varnish A '. (Manufacture of Laminated Plate) A glass woven fabric having a basis weight of 205 g / m ² was impregnated with the above-mentioned varnish A or A ′ and dried to obtain a pretreated substrate having each resin adhesion amount shown in Table 1. Further, the separately prepared bisphenol A type epoxy resin varnish I was impregnated into the pretreated substrate and dried to obtain a prepreg I having a total resin adhesion amount of 40% by weight. Next, a bisphenol A type epoxy resin varnish II (in weight ratio: resin / filler = 100/50) mixed with an inorganic filler is impregnated into a glass nonwoven fabric having a basis weight of 50 g / m ² and dried to obtain a resin containing the filler. A prepreg II having an adhesion amount of 84% by weight was obtained. Six plies of prepreg II are stacked, one ply of prepreg I is placed on each side of the ply, and a copper foil with a thickness of 18 μm is placed on both sides of the ply. A tension laminate was obtained.

[0012]

[Table 1]

Table 3 shows the characteristics of each of the above laminated plates. In Table 3, the solder crack occurrence rate of Example 5 is higher than that of the other Examples, but only 0.1 part by weight of the dimer acid-modified epoxy resin (dimer in Example 5 is used. The total amount of the acid-modified epoxy resin and the propylene oxide-added bisphenol A type epoxy resin) is lower than that of the conventional laminated plate in which the glass woven fabric is pretreated with the varnish, and the heat resistance is improved. I confirmed that. Since the solder crack generation rate is low in the vertical direction, the longitudinal direction of SMD mounting is aligned with the vertical direction of the substrate having a low solder crack generation rate.
(Generally, the weaving density of warp and weft of glass woven fabric is
It is said that the warp yarn has a higher weave density and is less susceptible to the thermal expansion of the resin. ) Conventional Examples 1 to 3 As the pretreatment varnish, those having the composition shown in Table 2 were used. And the pretreatment base material of each resin adhesion amount shown in Table 2 was obtained. Thereafter, in the same manner as in the above embodiment, the thickness is 1.6 mm.
A composite type copper clad laminate of was obtained. Incidentally, in Conventional Example 3, the pretreatment was not performed. The characteristics of each laminate are shown in Table 4.

[0014]

[Table 2]

[0015]

[Table 3]

(Note) (1) JIS method (2) P.C.T. Conditions: 121 ° C, 2 atm, 6 hr (3) Sample: Normal state, solder temperature: 300 ° C (4) Solder crack occurrence rate (n = 100, # 3125 chip): -30 ° C and 120 ° C repeated 1000 cycles (5) Sample size: 340 x 255 mm, number of samples: average value of 12 workpieces, processing step: full surface etching + 150 ° C 3
Heat for 0 minutes

[0017]

[Table 4]

Examples 7 to 12 and Comparative Examples 4 to 6 The dimer acid-modified epoxy resin or the dimer acid-modified epoxy resin / novolac type phenol resin pre-reaction product and the propylene oxide-added bisphenol A type epoxy resin in the above examples are shown in Table 5 A bisphenol A-type epoxy resin varnish III was prepared in an amount shown in Table 1. A glass woven cloth having a basis weight of 205 g / m ² was impregnated with the varnish III and dried to prepare a prepreg III having a resin adhesion amount of 40% by weight.
Got 6 plies of prepreg II are piled up, and 1 ply of prepreg III is placed on each side of the prepreg II.
A copper foil having a thickness of μm was placed on the copper foil, and heat-pressure lamination molding was performed to obtain a 1.6 mm thick composite-type copper-clad laminate.

[0019]

[Table 5]

Table 7 shows the characteristics of each of the above laminated plates. In Table 7, the rate of occurrence of solder cracks in Example 11 is higher than that in other Examples, but only 0.1% by weight of dimer acid-modified epoxy resin (dimer in Example 11 is used. Equivalent amount of acid-modified epoxy resin and propylene oxide-added bisphenol A type epoxy resin)
It was confirmed that the occurrence rate of solder cracks was lower and the heat resistance and the like were improved as compared with the conventional laminated plate using a prepreg obtained by impregnating and drying a mixed varnish in a glass woven fabric.

Conventional Examples 4 to 6 Bisphenol A prepared by blending the dimer acid-modified epoxy resin or propylene oxide-added bisphenol A type epoxy resin in the above Examples in the blending amounts shown in Table 6.
A type epoxy resin varnish IV was prepared. Basis weight 205g / m ²
The above-mentioned glass woven fabric was impregnated with the varnish IV and dried to obtain a prepreg VI having a resin adhesion amount of 40% by weight. Six plies of prepreg II are stacked, one ply of prepreg IV is placed on each side of the prepreg IV, and a copper foil with a thickness of 18 μm is placed on both sides of the prepreg IV. A tension laminate was obtained. Incidentally, Conventional Example 6 is a case in which neither the dimer acid-modified epoxy resin nor the propylene oxide-added bisphenol A type epoxy resin was blended. Table 8 shows the characteristics of each laminate.

[0022]

[Table 6]

[0023]

[Table 7]

[0024]

[Table 8]

[0025]

As described above, according to the method of the present invention, as a laminated board used for the substrate of the SMD compatible printed wiring board, the plane direction necessary for ensuring the solder connection reliability of the SMD is centered. In addition to lowering the elastic modulus, it was possible to secure heat resistance, moisture resistance, and metal foil peeling strength. By ensuring moisture-proof insulation, it is possible to provide narrow-pitch through-holes, which has a higher density than conventional SMDs.
A corresponding printed wiring board can be manufactured. further,
The warp of the laminated plate could be made small. Also,
If a pre-reacted product with a novolac type phenolic resin is used as the dimer acid-modified epoxy resin, the same adhesion amount to the sheet-shaped substrate, or the same compounding amount to the thermosetting resin, when compared with the heat resistance, The copper foil peel strength can be further improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // C08L 63:00 8830-4J (72) Inventor Tatsu Sakaguchi 2-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo No. 1 Shinshin Door Electric Co., Ltd.

Claims (6)

[Claims] 1. A method for producing a laminated sheet comprising a sheet-like base material made of glass fibers impregnated with a thermosetting resin, and superposing the heat-curable resin and heat-pressing the laminated base material, wherein the sheet-like base material of the surface layer is made of glass woven cloth. In the production of the laminated sheet, at least the sheet-like base material disposed on the surface layer is impregnated with the thermosetting resin before the dimer acid-modified epoxy resin (A) and propylene oxide-added bisphenol A type epoxy resin (B). Pretreatment with the combination composition of (2), the use ratio of both is (A) / (B) = 20/80 to 90/10 as a solid weight ratio, and the adhesion amount to the sheet-shaped substrate is 30% by weight. % Or less, a method for manufacturing a laminated board. 2. The amount of a combined composition of a dimer acid-modified epoxy resin and a propylene oxide-added bisphenol A type epoxy resin attached to a sheet-like substrate is 10 to 30% by weight.
The method for producing a laminated board according to claim 1, wherein: 3. The method for producing a laminate according to claim 1, wherein the dimer acid-modified epoxy resin is preliminarily reacted with a novolac type phenol resin. 4. A sheet-like base material made of glass fiber, which is impregnated with a thermosetting resin, is laminated under heat and pressure to produce a laminate, and the sheet-like base material of the surface layer is made of glass woven cloth. In the production of the laminated sheet, the thermosetting resin to be impregnated into the sheet-shaped base material disposed on the surface layer is a dimer acid-modified epoxy resin (A) and a propylene oxide-added bisphenol A type epoxy resin (B). The mold weight ratio,
(A) / (B) = 20/80 to 90/10, and the compounding amount is 40 parts or less with respect to 100 parts by weight of the thermosetting resin in terms of solid weight. .. 5. A compounding amount of a combination composition of a dimer acid-modified epoxy resin and a propylene oxide-added bisphenol A type epoxy resin is set to 20 to 40 parts with respect to 100 parts by weight of a solid part of a thermosetting resin. Claim 4 characterized by
A method for producing the laminated plate described. 6. The method for producing a laminated plate according to claim 4, wherein the dimer acid-modified epoxy resin is preliminarily reacted with a novolac type phenol resin.