JPH07302977A - Manufacture of multilayer printed-wiring board and copper-clad laminated board used for it - Google Patents

Abstract

PURPOSE:To obtain a one-sided copper-clad laminated board whose costs are reduced by effectively utilizing a production line and in which a warp is not generated. CONSTITUTION:A manufacturing process includes a process wherein prepregs 1 are arranged on both faces of a mold releasing material 3, copper coils 2 are arranged additionally on both sides of them, this assembly is arranged between one set of mirror face plates 4 and a copper=clad laminated board is formed by a heating process, a process wherein prescribed circuits are formed simultaneously on both faces of the copper-clad laminated board and the copper-clad laminated board is separated into one-sided circuit boards and a process wherein the separated copper-clad laminated board is overlapped arbitrarily with the other copper-clad laminated board and the prepreg 1 or the copper foil 2 and the prepreg 1 and they are arranged between one set of mirror face plates so as to be laminated and integrated by a heating press. In addition, the contact force of a one-sided base material, on one side, constituting the copper-clad laminated board is set at 10 to 500g/cm, and a material whose coefficient of thermal expansion is larger than that of the mirror face plates 4 is used for the mold releasing material 1.

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 multilayer printed wiring board and a copper clad laminate used for the same, and more particularly to a copper clad laminate obtained by closely fixing one sided copper clad laminate back to back via a release material. After forming a desired circuit pattern using, the single-sided circuit board is released from the release material and separated, and then another copper-clad laminate and prepreg (thermosetting resin-impregnated base material), or copper foil and The present invention relates to a method for producing a multilayer printed wiring board in which prepregs are arbitrarily overlapped to be laminated and integrated, and a copper clad laminate used for the method.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a multilayer printed wiring board, the following method has been adopted for manufacturing a 6-layer blind through-hole substrate as shown in FIG. 9, for example. First, as an inner layer substrate for forming the second layer circuit and the fifth layer circuit, a desired circuit is formed by a conventional method using a single-sided copper clad laminate, respectively, and then a single-sided copper clad having a second layer circuit is formed. A prepreg and a copper foil are arbitrarily stacked on top of each other around the laminated plate and laminated by a method such as hot pressing to obtain a laminated plate having a three-layer structure. Further, a laminated plate having a three-layer structure centering on a single-sided copper clad plate having a fifth layer circuit can be obtained by the same method. After that, through holes for through holes are formed in necessary portions of these laminated plates, and then circuits are formed on both sides by a conventional method to form a three-layer circuit board from a first layer circuit to a third layer circuit. Also, three-layer circuit boards from the fourth layer circuit to the sixth layer circuit are obtained. Next, the both three-layer circuit boards are sandwiched between prepregs and hot-pressed to form through-holes for through holes in the obtained copper-clad laminate by a drill or the like, and then pattern formation is carried out by an ordinary method. A blind through-hole multilayer printed wiring board having a 6-layer circuit is obtained.

[0003]

However, in this method for manufacturing a multilayer printed wiring board, a single-sided copper clad laminate is usually used as the inner layer substrate for forming the second layer circuit and the fifth layer circuit. A desired circuit is formed one by one by a method (generally a subtractive method).
However, the circuit of the inner layer substrate is formed on only one side, which is extremely inefficient in terms of effective utilization of the production line. This is, so to speak, unavoidable,
Further, in the case of manufacturing a printed wiring board having a high multilayer circuit structure (for example, an 8-layer circuit, further a 12-layer circuit, etc.), it is necessary to repeat the process of forming and laminating the inner layer circuit as in the above method. Therefore, in terms of productivity of the manufacturing line, the load increases, which causes a problem. That is, in terms of effective utilization of the production line, the higher the multilayer printed circuit board, the greater the inefficiency rate.

Further, since the single-sided copper-clad laminate itself has an asymmetric layer structure, there is a problem that warpage occurs.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a multilayer printed wiring board which can realize effective use of a production line and reduce the manufacturing cost. Another object of the present invention is to provide a copper-clad laminate for obtaining a single-sided copper-clad laminate that is suitable for manufacturing this multilayer printed wiring board and has no problems such as warpage at low cost.

[0006]

The invention according to claim 1 for solving the above-mentioned problems is that "a thermosetting resin-impregnated base material is arranged on both sides of a release material, and copper foil is further provided on both sides thereof. A step of arranging them and arranging them between a set of mirror-finished plates to form a copper-clad laminate by heating and pressing, after forming desired circuits on both sides of the copper-clad laminate at the same time, Step of separating into two single-sided circuit boards, the separated copper-clad laminate is laminated with another copper-clad laminate and prepreg or copper foil and prepreg as desired, and placed between one set of mirror-finished plates and heated and pressed. Is a method of manufacturing a multilayer printed wiring board including a step of "integrating and stacking".

Further, the invention according to claim 2 is that "thermosetting resin-impregnated base materials are arranged on both sides of the release material, and copper foils are further arranged on both sides thereof, and the copper foils are arranged between a pair of mirror surface plates. In the copper-clad laminate formed by hot pressing, the adhesion (90 ° peel strength) between any one-sided base material forming the copper-clad laminate and the release material is 10 g / cm to
It is a copper-clad laminate for obtaining a single-sided copper-clad laminate suitable for manufacturing a multilayer printed wiring board, which is characterized by "500 g / cm". The combination of manufacturing the two single-sided copper clad laminates may be formed by a pair of two-layer circuit and five-layer circuit in the case of, for example, a six-layer substrate, or by forming two-layer circuits or five-layer circuits. You may. Furthermore, the release material is preferably a material having a coefficient of thermal expansion larger than that of the mirror surface plate used for hot pressing, and is preferably aluminum (foil) from the viewpoint of material cost.

[0008]

According to the first aspect of the present invention, the thermosetting resin-impregnated base material is arranged on both sides of the release material, and the copper foils are arranged on both sides of the base material. Since a board is used to form a circuit on both sides of the board at the same time, and then the board is separated from the mold release material to form a desired single-sided circuit board, it is possible to obtain two single-sided circuit boards by one circuit forming step. Therefore, the process cost can be reduced to about 1/2 of that required to obtain two single-sided circuit boards using two single-sided copper-clad laminates, and the manufacturing cost can be reduced.

According to the second aspect of the invention, thermosetting resin-impregnated base materials are placed on both sides of the release material, and copper foils are placed on both sides of the release material. In the plate, the adhesion force between one of the one-sided circuit boards constituting the copper clad laminate and the release material (90 ° peel strength, JI
S-C5016 measuring method) is 10 g / cm to 500 g / c
By controlling the surface condition of the release material so that m,
When forming desired circuits on both sides of the copper-clad laminate at the same time, the two laminated single-sided copper-clad laminates are not separated in the production line, and the two single-sided copper-clad laminates are formed after the circuit formation. When separated into two, the one-sided copper-clad laminate has a suitable strength that makes it easy to peel off from the release material.

Further, the release material is preferably a material having a coefficient of thermal expansion larger than that of the mirror surface plate used for hot pressing, and also a material having relatively high strength. From the viewpoint of material cost, aluminum (foil) is used. Is desirable. That is, the mold release material has a coefficient of thermal expansion larger than that of the mirror plate, and the rigidity is relatively large, so that the curing shrinkage of the base material on the mold release material side (the portion in close contact with the mold release material) progresses. Is suppressed almost in the same manner as on the copper foil side (the portion that is in close contact with the copper foil), so that it is possible to prevent the single-sided copper-clad laminate from warping after separating the two.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to FIGS. Prepreg (product name: R-1) which is a thermosetting resin-impregnated base material as a material for obtaining a single-sided copper clad laminate made of glass / epoxy resin and having a thickness of 0.1 mm
661, manufactured by Matsushita Electric Works, Ltd. 1 and two sets of 18 μm thick copper foil (trade name: 3EC-3, manufactured by Mitsui Kinzoku Co., Ltd.) 2 are prepared. Then, each prepreg 1 is arranged with a mold release material (trade name: Sepanum, manufactured by Sun Aluminum Industry Co., Ltd.) 3 made of aluminum having a thickness of 40 μm sandwiched therebetween, and a copper foil 2 is arranged on the outside thereof (FIG. 1). ). This release material 3 has an aluminum base film surface coated with epoxy resin,
Further, a matting agent such as silica is added and an appropriate roughening treatment is performed to control the adhesion strength with the prepreg to a desired value.

Next, a copper plate having a mold release material 3 sandwiched between the prepregs 1 was hot-pressed using a set of mirror-faced plates 4 made of stainless steel (JIS standard: SUS630 austenitic stainless steel) having a thickness of 1 mm. The stretched laminated board 5 is formed (FIG. 2). When forming a plurality of copper clad laminates 5 at the same time, one more mirror-finished plate 4 than the number of copper-clad laminates 5 is used, and each copper-clad laminate 5 is sandwiched between the mirror-like plates 4. You may heat-press at once in the state of being. The heating and pressurizing press performs the pressing step in two steps, the first pressing step is at a pressure of 10 Kgf / cm ² for 20 minutes, and the second pressing step is at a pressure of 30 Kgf / cm ² for 160 minutes.
I went for 0 minutes. The heating during pressing was carried out by raising the temperature from room temperature to 180 ° C. in 90 minutes, holding it at 180 ° C. for 40 minutes, and gradually cooling it so as to decrease from 180 ° C. to room temperature at 50.

After that, a conductor circuit 7 was formed on the copper clad laminate 5 by a tenting method using an etching resist film made of a dry film to obtain a double-sided circuit board 6 (FIG. 3). At this time, since the release material 3 is roughened by applying an epoxy resin on the surface of the aluminum base film and further adding a matting agent such as silica, the copper clad laminate 5 is held by an appropriate adhesive force. Therefore, it could be processed in the same manner as a normal double-sided circuit board without peeling due to external stress such as shower in the etching process. Further, by using the copper clad laminate 5 of the three-layer sandwich structure of the present embodiment, the single-sided circuit boards 61 and 62, which have conventionally been separately formed, can be formed simultaneously.
It has become possible to improve productivity.

Next, the mold release material 3 to the single-sided circuit boards 61 and 6 are used.
Two were separated (Fig. 4). At this time, since the release material 3 is roughened by applying an epoxy resin on the surface of the aluminum base film and further adding a matting agent such as silica, the single-sided circuit boards 61, 62 can be separated relatively easily. . Further, since the release material is a material having a coefficient of thermal expansion larger than that of the mirror plate used for hot pressing, and aluminum, which is a material having a relatively high strength, is used, the release material side (the part which is in close contact with the release material) ) The progress of curing shrinkage of the base material is suppressed almost in the same way as on the copper foil side (the part that is in close contact with the copper foil), and after separating them, each single-sided copper clad laminate will interfere with the post process. No significant warpage occurred.

Next, a copper-clad laminate 20 having the single-sided copper-clad laminate 61 sandwiched by the center is formed by hot pressing using a set of stainless steel mirror-finished plates 4 having a thickness of 1 mm (FIG. 5). ). When a plurality of copper clad laminates 20 are formed at the same time, one mirror plate 4 is used more than the number of copper clad laminates 20, and one copper clad laminate 20 is provided between the mirror clad plates 4 as described above. You may heat-press at once in the state pinched by each. As for the heating press, the pressing step was performed in two stages as described above. The other conditions are the same.

Next, after drilling holes for through-holes in the required portions of the copper-clad laminate 20 (FIG. 6), through-hole plating (not shown) is performed to form a circuit on one side by a conventional method. A circuit board 21 having a three-layer structure was obtained. Also, the fourth
The sixth to sixth layers of the copper clad laminate 30 were prepared in the same manner (FIG. 7). Further, similarly, punching, through-hole plating, and circuit formation were performed to obtain a circuit board 31 having a three-layer structure.

Next, the circuit boards 21 and 3 having the above three-layer structure.
0.1 mm thick prepreg (Product name: R-1
661, Matsushita Electric Works Co., Ltd. 8 were sandwiched and hot-pressed. The conditions of the hot press are the same as described above (FIG. 8). After forming the through holes 9 in the obtained laminated plate by drilling with a drill or the like, through hole plating and circuit formation were carried out to obtain a multilayer printed wiring board 100 with 6 layers blind through holes (FIG. 9).

Although the present embodiment has been described with reference to a multilayer printed wiring board having a 6-layer blind through hole as an example, a 6-layer board is used when manufacturing the substrate of the 3-layer sandwich structure according to the present invention. However, the number of circuit layers is not limited to the above, and may be a four-layer substrate or an eight-layer substrate.
Further, the present invention is not limited to the blind through hole substrate, but can be applied to a multilayer printed wiring board having only through holes.

The present invention can be embodied as follows. (1) Although the release material 3 is made of aluminum as a base material in the above embodiment, the following structure may be used instead, which has a higher coefficient of thermal expansion than the stainless specular plate 4. Metal such as lead (coefficient of thermal expansion: 29 × 10 ^-6 / ° C), glass / epoxy resin with stainless steel foil on both sides, release film made of fluororesin such as Teflon on both sides of glass / epoxy resin Sticked things. When a glass / epoxy resin is used for the mold release material 3, it is necessary to make it slightly thicker in order to obtain rigidity. The coefficient of thermal expansion of glass / epoxy resin is 20 to 30 × 10 ⁻⁶ / ° C, and the coefficient of thermal expansion of fluororesin is 30 to 55 × 10 ⁻⁶ / ° C. decide.

(2) The surface of the mirror surface plate 4 that comes into contact with the copper foil 2 has a convex shape having a predetermined curvature, and both surfaces of the release material 3 have a concave surface shape that matches the convex surface shape of the mirror surface plate 4 during hot pressing. The prepreg 1 on the side in contact with the release material 3 may be extended in an arc shape. If you do this,
When the prepreg 1 is cured and contracted, the cured and contracted state is suppressed, so that the warp can be suppressed as in the above-described embodiment. In this case, the release material 3 preferably has a release film (Tedlar or the like) similar to the conventional one on the side that contacts the prepreg 1. Further, the convex shape of the mirror surface plate 4 and the concave shape of the release material 3 need to be curved in the direction in which the glass fiber of the prepreg 1 is bent.

(3) The thickness of the release material 3 may be changed arbitrarily. Note that the thickness range is 40 μ to 2 in consideration of the material cost of cutting and processing the copper clad laminate before release.
It is preferably 50μ. The optimum range for manufacturing is 40 μm to 100 μm.

(4) The material of the mirror surface plate 4 may be other kinds, for example, stainless steel such as JIS standards: 630-635, 650-653. (5) The conditions of the heating press may be changed arbitrarily. When changing the pressing pressure, the pressure of the first press (pre-press) is preferably 0~20kgf / cm ^2, the pressure of the second press is preferably 20~50kgf / cm ^2.

The technical ideas other than those described in the claims which can be understood from the above-described embodiments will be described below along with their effects.

(1) In the wiring board according to claim 3,
The release material was roughened by applying a thermosetting resin containing a matting agent on the surface of the aluminum base film. By doing so, the releasability from the base material and the adhesion between the single-sided wiring board and the base material when forming the multilayer board are improved.

(2) The surface of the mirror surface plate that comes into contact with the copper foil has a convex shape having a predetermined curvature, and both surfaces of the release material have a concave surface shape that matches the convex surface shape of the mirror surface plate. Even with this,
The warp of the substrate can be suppressed as much as possible.

(3) A method for producing a single-sided circuit board in which a release material is adhered to both sides of a thermosetting resin-impregnated base material with metal foil, and the coefficient of thermal expansion thereof is larger than that of the mirror plate. Even in this case, the warp of the substrate can be suppressed.

(4) A method for producing a single-sided circuit board in which a release agent is adhered to both surfaces of a thermosetting resin-impregnated base material with a fluororesin so that the coefficient of thermal expansion thereof is larger than that of the mirror plate. Even in this case, the warp of the substrate can be suppressed.

[0028]

As described in detail above, according to the present invention, it is possible to provide a method for manufacturing a multilayer printed wiring board, which enables effective utilization of a production line and reduces the manufacturing cost in manufacturing the multilayer printed wiring board. Further, it is possible to provide a copper-clad laminate for obtaining a single-sided copper-clad laminate that is suitable for manufacturing this multilayer printed wiring board and has no problems such as warpage at low cost.

[Brief description of drawings]

FIG. 1 is a schematic view showing a hot pressing step of a method for manufacturing a multilayer printed wiring board according to an example of the present invention.

FIG. 2 is a schematic view showing a copper clad laminate of the present invention.

FIG. 3 is a schematic diagram showing a state in which a circuit is formed on the copper clad laminate of FIG.

FIG. 4 is a schematic view showing a state where the copper clad laminate of FIG. 3 is separated.

FIG. 5 is a schematic view showing a heating press for forming a three-layer copper-clad laminate using a single-sided circuit board.

FIG. 6 is a schematic diagram showing a state in which the copper clad laminate of FIG. 5 is perforated.

FIG. 7 is a schematic view showing a state where holes are punched in the other copper clad laminate of three layers.

FIG. 8 is a schematic view showing a state in which the copper clad laminates of FIGS. 5 and 6 are integrally laminated.

FIG. 9 is a schematic diagram showing a multilayer printed wiring board obtained according to an example of the present invention.

[Explanation of symbols]

1 ... Thermosetting resin-impregnated base material (prepreg), 2 ... Copper foil,
3 ... Release material 4 ... Mirror surface plate, 5 ... Copper clad laminate, 6 ... Double-sided circuit board, 7 ...
Circuit 8 ... Prepreg, 9 ... Through hole, 20, 30 ... Copper clad laminate 21, 31 ... Circuit board, 100 ... Multilayer printed wiring board

Claims (3)

[Claims] 1. A thermosetting resin-impregnated base material is placed on both sides of a release material, copper foils are placed on both sides of the release material, and the copper foils are placed between a set of mirror-finished plates to form a copper-clad laminate by hot pressing. A step of forming desired circuits on both sides of the copper clad laminate at the same time, and then separating the copper clad laminate into two single-sided circuit boards; A method for producing a multilayer printed wiring board, which comprises a step of arbitrarily laminating a stretched laminated board and a prepreg, or a copper foil and a prepreg, and arranging them between a pair of mirror-finished boards and laminating and integrating them by a hot press. 2. A thermosetting resin-impregnated base material is placed on both sides of a release material, copper foils are placed on both sides of the release material, and the copper foils are placed between a set of mirror-finished plates and formed by hot pressing. In the laminate, the adhesion force (90 ° peel strength) between any one-sided base material forming the copper clad laminate and the release material is 10 g / cm.
A copper-clad laminate characterized by being ~ 500 g / cm. 3. The copper clad laminate according to claim 2, wherein the release material is aluminum.