JP2003347744A - Resin film for manufacturing multilayer printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin film for manufacturing a multilayer printed circuit board, which enables formation of an insulating layer having excellent insulation reliability, without damaging its adhesion to a conductive layer. <P>SOLUTION: The resin film 3 for manufacturing a multilayer printed circuit board is adhered to the surface of a circuit board 4 by vacuum lamination. In the lamination, stacking is performed using a first layer consisting of a thermosetting resin composition which comprises rubber constituents soluble in alkali and inorganic fillers, and a second layer consisting of a thermosetting resin composition which comprises neither the rubber constituents nor the inorganic fillers. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin film for producing a multilayer printed wiring board used for forming an insulating layer of a multilayer printed wiring board used for electronic equipment, electric equipment, computers, communication equipment and the like. It is about.

[0002]

2. Description of the Related Art In recent years, electronic components such as semiconductor chips and chip components have become lighter, thinner and smaller, and accordingly, so-called fine patterns in which the line width and line interval of a conductor circuit have a narrow pitch of 200 μ or less have been developed. There is a demand for a technique for manufacturing a printed wiring board having the same. In particular, there is a high demand for fine patterns on lands to which the mounted components such as the electronic components are connected, and recently, there have been demands for reducing the weight of printed wiring boards, ease of design, and increasing the speed of signals. It is necessary to meet the demands, and for this reason, the build-up multilayer printed wiring board, which is formed by sequentially laminating insulating layers and conductor layers on the structure of a general printed wiring board, (High density) is used as a major countermeasure.

[0003] In view of such technical background, in recent years, a resin film (additive adhesive) is bonded to the surface of a circuit board having a circuit to be an inner layer circuit and then cured.
A multi-layer printed wiring board is manufactured by forming an insulating layer on the surface of a circuit board, roughening the surface of the insulating layer with an alkaline oxidizing agent, and then forming a conductor layer serving as an outer layer circuit on the surface of the insulating layer. (For example, Japanese Patent Application Laid-Open No. 8-64960). In the method of forming an insulating layer by supplying a resin film in this manner, since the insulating layer does not include a base material such as glass cloth, the electrical characteristics such as speeding up of an electric signal and the multilayer printed wiring board are reduced. It has various advantages, such as a reduction in the total weight of the device and the need for a large-scale press for vacuum lamination during processing.

[0004] When the insulating layer is formed of a resin film as described above, the most important performance is the adhesion strength (adhesion strength) between the insulating layer and the conductor layer formed on the surface thereof. There are various methods for increasing the adhesion strength between the insulating layer and the conductor layer depending on a method of forming the conductor layer, and the like.
After roughening the surface of the insulating layer with permanganic acid, so that a multilayer printed wiring board can be formed at lower cost,
There is a demand for a method that can be used in a process of performing chemical copper plating on the surface of a roughened insulating layer and then performing electroplating to form a conductor layer.

[0005] Therefore, the following additive substances are blended in a matrix of a resin film formed of a heat-resistant resin or the like, and the insulating layer has an anchoring effect on the conductor layer so that the insulating layer and the conductor layer can be combined. Maintaining high adhesion strength is almost essential in the current material technology.

[0006] A resin component or an inorganic substance that can be easily formed in an insulating layer at a portion where a conductor layer bites by being chemically dissolved in a surface roughening step using permanganic acid.

[0007] An inorganic substance that is easily dropped from the insulating layer in the step of surface roughening with permanganic acid, thereby facilitating the formation of a portion where the conductor layer bites into the insulating layer.

[0008] As the above-mentioned additives, JP-A-5-3
Epoxidized butadiene rubber described in JP-A-20924;
Acrylonitrile butadiene rubber described in JP-A-5-320924, cross-linked acrylonitrile-butadiene rubber described in JP-A-8-139449,
Examples include silicone rubber fine powder described in 237084, acid-soluble epoxy fine powder described in JP-A-7-34048, and calcium carbonate described in JP-A-11-340625, Examples of the above-mentioned additive substance include finely divided silica described in JP-A-11-340625 and spherical porous silica described in JP-A-2001-94261.

[0009]

SUMMARY OF THE INVENTION The above additives are mixed in a matrix of an insulating layer, and the surface of the insulating layer is chemically roughened with permanganic acid or the like, thereby forming irregularities on the surface of the insulating layer. The insulating layer and the conductor layer can be efficiently formed, and the adhesion strength between the insulating layer and the conductor layer can be increased.

However, new technical issues such as generation of an interface between the matrix of the insulating layer and the additive substance have been emphasized,
There is a problem that cannot be solved simply by blending the above-mentioned additive substances. In particular, when the thickness of the insulating layer is reduced, the influence on the insulation reliability is seriously reduced, which has been a major obstacle in increasing the density of the multilayer printed wiring board while reducing the thickness.

[0011] The present invention has been made in view of the above points, and a resin film for manufacturing a multilayer printed wiring board capable of forming an insulating layer having excellent insulation reliability without impairing adhesion to a conductor layer. It is intended to provide.

[0012]

The resin film for manufacturing a multilayer printed wiring board according to the first aspect of the present invention is a resin film for manufacturing a multilayer printed wiring board adhered to the surface of a circuit board by vacuum lamination. A first layer 3a made of a thermosetting resin composition containing a rubber component soluble in alkali and an inorganic filler, and a second layer 3b made of a thermosetting resin composition containing no rubber component and no inorganic filler. Are laminated.

Further, the resin film 3 for manufacturing a multilayer printed wiring board according to claim 2 of the present invention,
The thermosetting resin composition of the first layer 3a contains 2 to 40 rubber components.
% By mass, and 2 to 20% by mass of an inorganic filler.

According to a third aspect of the present invention, there is provided a resin film 3 for producing a multilayer printed wiring board, wherein the first layer 3a has a thickness of 10 to 50 μm and the second layer 3b
Is formed to have a thickness of 10 to 30 μm, respectively.

[0015]

Embodiments of the present invention will be described below.

In the present invention, as the thermosetting resin constituting the first layer and the second layer, epoxy resins such as bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, liquid brominated bisphenol A type epoxy resin, etc. Can be used. The thermosetting resin can be used singly or in combination.

In the present invention, as the rubber component soluble in alkali, one or a combination of those described in the above-mentioned publications can be used. , Silicone rubber and the like.

In the present invention, as the inorganic filler, those described in the above publications can be used alone or in combination of two or more. Examples thereof include calcium carbonate powder, fine silica, spherical silica, and spherical porous silica. Can be. The inorganic filler has a particle size of 0.1 to 10 μm.
m can be suitably used, but the present invention is not limited to this.

The thermosetting resin composition for forming the first layer is prepared by blending the above-mentioned thermosetting resin, a rubber component, an inorganic filler and a curing agent for the thermosetting resin. can do. Further, a thermosetting resin composition for forming the second layer can be prepared by blending the above thermosetting resin and a curing agent. That is, the thermosetting resin composition for forming the second layer does not include both the rubber component and the inorganic filler in the thermosetting resin composition for forming the first layer. The curing agent may be appropriately selected depending on the type of the thermosetting resin or the like. When the thermosetting resin is an epoxy resin, phenol novolak or the like can be used. Further, the mixing ratio of the thermosetting resin and the curing agent can be appropriately set so that the thermosetting resin composition is cured, but when the thermosetting resin is an epoxy resin, for example, an epoxy group The blending ratio of the thermosetting resin and the curing agent can be set so that 0.8 to 1.2 equivalents of the curing agent are blended per equivalent.

The thermosetting resin and the curing agent used for the thermosetting resin composition of the first layer are the same as the thermosetting resin and the curing agent used for the thermosetting resin composition of the second layer. May be different. In addition, any of the above thermosetting resin compositions can be made into a varnish by dissolving and dispersing in a solvent. As a solvent for forming a varnish, methyl ethyl ketone (MEK), dimethylformamide (DMF), or the like can be used.

The thermosetting resin composition for forming the first layer preferably contains 2 to 40% by mass of a rubber component and 2 to 20% by mass of an inorganic filler based on the total amount. When the content of the rubber component is less than 2% by mass or the content of the inorganic filler is less than 2% by mass, a roughened surface of the insulating layer cannot be sufficiently obtained, and the adhesion of the circuit (conductor layer) is poor. If the content of the rubber component is more than 40% by mass or the content of the inorganic filler is more than 20% by mass, the insulation property of the insulating layer is deteriorated, and the insulation reliability is reduced. There is a risk that the problem will occur.

The resin film for producing a multilayer printed wiring board according to the present invention comprises a first layer formed from a thermosetting resin composition containing a rubber component soluble in alkali and an inorganic filler. It can be formed by forming a second layer from a thermosetting resin composition containing no filler and laminating the first layer and the second layer. The present invention is performed as follows. First, a first layer is formed by applying a thermosetting resin composition containing a rubber component soluble in an alkali and an inorganic filler to the surface of a support and drying it. As the support, a synthetic resin film such as polyethylene terephthalate (PET) can be used. Next, the second layer is formed by applying and drying the thermosetting resin composition containing no rubber component and no inorganic filler on the surface of the first layer formed on the support. Any of the above thermosetting resin compositions can be applied by an application means such as a bar coat coater or screen printing. In addition, any of the above thermosetting resin compositions is easy to apply if it is a varnish, and is easily set to a predetermined thickness. After the formation of the second layer, a cover material may be arranged on the surface. As the cover material, polyethylene terephthalate (P
A film made of a synthetic resin such as ET) can be used. Further, the first layer and the second layer may be semi-cured to a B-stage state by heating or the like.

The thickness of the first layer is preferably set to 10 to 50 μm. If the thickness of the first layer is less than 10 μm,
When the first layer is too thin, the first layer may be damaged during the surface roughening and a problem may occur that the surface cannot be roughened. If the thickness of the first layer is more than 50 μm, the thickness of the insulating layer may be reduced. The ratio of the thickness of the first layer to the thickness of the insulating layer becomes too large, and the insulating characteristics of the insulating layer are likely to be deteriorated, which may cause a problem that the insulating reliability is reduced. The thickness of the second layer is 10 to
Preferably, it is set to 30 μm. The thickness of the second layer is 10
If the thickness is less than μm, the effect of the present invention of forming an insulating layer having excellent insulation reliability by preventing deterioration of the insulating properties of the insulating layer because the thickness of the second layer is too thin may not be obtained. There is no particular problem even if the thickness of the second layer is larger than 30 μm, but when the insulating layer having a predetermined thickness is formed, the ratio of the thickness of the second layer to the thickness of the insulating layer becomes too large, and the relative thickness becomes relatively large. The thickness of the first layer may be reduced,
When the first layer is roughened, the first layer may be damaged and may not be able to be roughened.

The first layer and the second layer have a melt viscosity in a region where lamination can be performed in a manufacturing process of a multilayer printed wiring board using a vacuum laminator to be described later. The melt viscosity when mixing the thermosetting resin composition of the second layer and the thermosetting resin composition of the second layer is preferably 500 to 10,000 poise at 110 ° C. The composition of the thermosetting resin composition of the first layer and the composition of the thermosetting resin composition of the second layer are appropriately set.

The resin film for manufacturing a multilayer printed wiring board formed as described above is used for manufacturing a multilayer printed wiring board using a vacuum laminator.

FIG. 1 shows an example of a vacuum laminator, in which a pair of heating plates 1 and 1 having a built-in heating element 18 such as a heater are arranged vertically. The pair of upper and lower heating plates 1, 1 are driven in the direction of approaching and separating by raising and lowering the lower heating plate 1.
A concave portion 19 for evacuation is provided on the upper surface of the lower heating plate 1, and a perforated metal plate 20 having a large number of small holes 21 provided on the entire surface thereof is affixed in a convex shape in the concave portion 19 for evacuation. ing.
As the perforated metal plate 20, a stainless steel punched metal plate can be used. A packing 22 is formed on the upper surface of the hot platen 1 so as to surround the recess 19 for evacuation.
Is provided, and when the hot plates 1 and 1 are closed by closing the mold, the evacuation concave portion 19 is sealed. The upper heating platen 1 is provided with a vacuum evacuation hole 23 communicating with the vacuum evacuation recess 19, and by evacuating the air in the sealed vacuum evacuation recess 19 from the vacuum evacuation hole 23, a vacuum is formed. The inside of the pulling recess 19 can be evacuated.

In the concave portion 19 for evacuation of the lower hot platen 1,
In order to cover the upper surface of the perforated metal plate 20, the diaphragm 16
Is attached. As the diaphragm 16, a sheet of a soft rubber-like elastic material such as chloroprene rubber, silicon-based rubber, or fluorine-based resin can be used. A sealed space 25 in which air is sealed is formed between the diaphragm 16 and the bottom surface of the evacuation recess 19 of the lower hot platen 1. The lower hot platen 1 communicates with the closed space 25. The diaphragm 16 can be inflated like a balloon by supplying pressurized air or the like to the closed space 25 from the flow hole 26 formed in the airtight space 25. Further, a molded plate 2 having a smooth surface is attached to the upper surface of the diaphragm 16 by bonding or the like. The above-described perforated metal plate 20 is for preventing the diaphragm 16 from lowering further when the diaphragm 16 is not expanded.

On the other hand, an elastic plate 15 made of cushion rubber is attached to the lower surface of the upper heating plate 1, and a molded plate 2 having a smooth surface is attached to the lower surface of the elastic plate 15 by bonding or the like. Have been. Formed plates 2 provided on the lower hot platen 1 and the upper hot platen 1, respectively, are disposed at positions vertically opposed to each other. As the formed plate 2, a mirror-finished metal plate such as a SUS plate, a brass plate, or a copper plate is used. Can be used. Also, the molded plate 2 whose outer size is smaller than the outer size of the circuit board 4 and larger than the outer size of the resin film 3 is used.

The upper heating plate 1 includes a release cylinder 8.
Is provided. The release cylinder 8 is formed by providing a cylinder rod 38 to a cylinder 37 such as an air cylinder so as to protrude downward, and is attached to both sides of the hot platen 1, respectively. In FIG. 1, a vibrator 9 for generating vibration is attached to the side surface of the hot platen 1, and the release cylinder 8 is attached to the vibrator 9.
Is formed so that the release cylinder 8 can be vibrated. In this release cylinder 8, the cylinder rod 38 is immersed in the cylinder 37 so that the lower end is located above the lower surface of the forming plate 2 provided on the upper hot platen 1. Activate the cylinder 8 to move the cylinder rod 38 to the cylinder 37
, The lower end of the cylinder rod 38 is formed to protrude below the lower surface of the forming plate 2.

FIG. 2 shows an example of a transport device using the transport film 5, in which a pair of elongated transport films 5, 5 are vertically opposed to each other. The transport film 5 is unwound from an unwinding roll 28a, and is wound up by a winding roll 29a through a space between the hot plates 1 and 1 which are arranged vertically. Also,
The lower transporting film 5 is unwound from the unwinding roll 28b, passes over the set table 30, passes through the hot plates 1, 1 which are vertically opposed to each other, and takes up the winding roll 2.
9b. As the transport film 5, a thin film having heat resistance is preferable, and for example, a PET film can be used.

On the other hand, as shown in FIG. 3, the circuit board 4 used as the inner layer core material is formed by providing a circuit 33 serving as an inner layer circuit on the surface of an insulating plate 32. The portion is provided with a guide hole 34 used for positioning or the like in a circuit forming step or the like. The resin film 3 includes the first layer 3a and the second layer 3b as described above. The resin film 3 is formed in a size corresponding to a range where a circuit needs to be formed on the wiring board. Therefore, the outer dimensions of the resin film 3 are formed smaller than the outer dimensions of the circuit board 4, and when the resin film 3 is stacked on the circuit board 4, the outer peripheral end of the circuit board 4 where the guide holes 34 are provided is provided. The end of the resin film 3 does not extend to the end.

In laminating the insulating layer 6 made of the resin film 3 on the circuit board 4 and forming a multilayer printed wiring board by the build-up method, first, FIG.
Resin films 3 on both upper and lower sides of circuit board 4
Are placed on a set table 30 and placed on a lower transport film 5. At this time, the support and the cover material have been removed from the resin film 3. The resin film 3 is placed so that the second layer 3b side contacts the surface of the circuit board 4. Further, the pair of upper and lower transport films 5, 5 are fed out from the feeding rolls 28a, 28b when the hot plates 1, 1 are open, and are transported. As a result, the circuit board 4 and the resin film 3 are sandwiched between the transfer films 5 and 5 in FIG.
As shown in (a), it can be introduced and set between the hot plates 1, 1.

Next, the lower hot platen 1 is driven upward to clamp the upper and lower hot plates 1, 1 to form a molded plate 2 of the upper hot platen 1 and a molded plate 2 of the lower hot platen 1. The circuit board 4 and the resin film 3 are sandwiched between them, and the heating and pressing is performed in this state. At this time, the inside of the evacuation recess 19, which is closed by clamping the upper and lower heating plates 1, 1, is evacuated from the evacuation hole 23, and from the circulation hole 26 to the sealed space 25 on the back surface of the diaphragm 16. The diaphragm 16 is expanded by supplying pressurized air. Then Figure 1
As shown in FIG. 2B, the molded plates 2 and 2 are brought into close contact with the surfaces of the resin films 3 and 3 stacked on both sides of the circuit board 4 via the transfer films 5 and 5, respectively. Diaphragms 16 swelled by pressurized air are elastically deformed and adhere to both surfaces of the four circumferential ends located outside the film 3.

Then, in this state, the resin films 3 stacked on both sides of the circuit board 4 are pressed with
In this case, the insulating layer 6 formed by melting and curing the resin film 3 by heating and pressing is formed as shown in FIG. 3 (b). The circuit board 7 with an insulating layer laminated on both sides of the board 4 can be formed. Here, in performing the molding as described above, the surface of the resin film 3 is pressed by the smooth and hard molding plate 2, so that the resin which has been melted by the heating of the resin film 3 is molded. 2
And can be forced to flow between the circuits 33 to be filled, thereby preventing bubbles from remaining between the circuits 33 and remaining bubbles in the insulating layer 6. is there. In addition, since the surface of the insulating layer 6 is pressed smoothly by the smooth formed plate 2, the surface of the insulating layer 6 can be prevented from being uneven. Further, since the molding is performed in a state where the diaphragm 16 is in close contact with the peripheral edge of the circuit board 4, the diaphragm 16 is in close contact with the circuit board 4 so that the resin in which the resin film 3 has melted flows out to the end of the circuit board 4. This prevents the molten resin of the resin film 3 from flowing to and protruding from the end of the circuit board 4, and a guide provided at the end of the circuit board 4. The hole 34 can be prevented from being filled with the protruding resin of the insulating layer 6. The molding conditions using the above vacuum laminator are as follows:
The pressure can be set to 0.1 to 2.0 MPa and the time can be set to 10 to 600 seconds, but is not limited thereto.

The above-mentioned molding is performed by using the concave portion 19 for evacuation.
This is performed in a vacuum-evacuated system, and since the heat and pressure molding of the resin film 3 can be performed in the absence of air, the generation of air bubbles in the insulating layer 6 is prevented. Is what you can do. still,
In FIG. 1, the hot platen 1 is provided with a concave portion 19 for evacuation and the hot platen 1 is formed into a vacuum evacuation system. May be housed in the vacuum chamber 35 and the inside of the vacuum chamber 35 may be evacuated to perform molding.

After the molding is completed as described above,
The lower hot platen 1 is moved downward, as shown in FIG.
The transporting films 5 and 5 are transported by winding the transporting films 5 and 5 around winding rolls 29a and 29b, and the wiring board 7 held between the transporting films 5 and 5 is heated. It can be sent out from between the boards 1 and 1 and taken out. A film feed chuck 39 is provided on the side of the hot platen 1, and the transfer films 5, 5 are chucked and moved by the film feed chuck 39, so that the transfer films 5, 5 are transferred. You may.

At this time, the molding plate 2 and the transfer film 5 come into close contact with each other in vacuum during the above-mentioned molding, and the transfer film 5 adheres to the formation plate 2 even when the upper and lower hot plates 1, 1 are opened. In particular, when the forming is performed in a vacuum system, such a close contact between the formed plate 2 and the transfer film 5 is likely to occur. In FIG. 1, the lower hot platen 1 is driven up and down, and the upper hot platen 1 is in a fixed state. In many cases, the transfer film 5 is in close contact with the molded plate 2. Therefore, when the upper and lower hot plates 1 and 1 are opened after the molding is completed, the mold release cylinder 8 attached to the upper hot plate 1 is operated in conjunction with the opening of the molds, and as shown in FIG. The cylinder rod 38 of the release cylinder 8 is projected downward, thereby pressing the transporting film 5 with the tip of the cylinder rod 38 and separating the transporting film 5 from the upper forming plate 2 of the hot platen 1. To release the transfer film 5 from the molded plate 2. At this time,
At the same time as the release cylinder 8 is activated, the vibrator 9 is also activated to apply vibration to the release cylinder 8. By pressing the transport film 5 while applying vibration, the transport film 5 is It is designed to be easily peeled off from the molded plate 2. In this way, even if the transfer film 5 is in close contact with the forming plate 2, the transfer film 5 can be easily peeled off, so that the transfer film 5 is not broken when transferring the transfer film 5, and the forming plate 2 is not broken. This eliminates the need to take extra time to peel off the transport film 5 from 2, thereby lowering the molding productivity.

After the circuit board 7 with the insulating layer sent out between the hot plates 1 and 1 as described above is separated from the transport films 5 and 5 and taken out, each transport film 5 and 5 is wound up. It is wound on rolls 29a and 29b. In addition, in the circuit board 7 with an insulating layer obtained by molding in this manner, the circuit 33 provided on the surface of the circuit board 4 is covered with the insulating layer 6. Then, a circuit to be an outer layer circuit in the next step is formed on the surface of the insulating layer 6.

In forming a circuit on the surface of the insulating layer 6, an additive method conventionally used in the manufacture of printed wiring boards can be employed. First, a via hole communicating with the circuit 33 of the circuit board 4 and a through hole penetrating the insulating layer 6 and the circuit board 4 are formed in the insulating layer 6. At this time, drilling can be performed using a laser or a drill. Next, an alkaline oxidizing agent such as permanganate is supplied to the surface of the insulating layer 6. At this time,
The oxidizing agent is supplied in the form of an aqueous solution dissolved in water. Since the surface of the insulating layer 6 is formed of the first layer containing the rubber component soluble in alkali and the inorganic filler, the rubber component is dissolved by the alkaline oxidizing agent and the inorganic filler is removed by the insulating layer 6. Thus, the surface of the insulating layer 6 (including the inner peripheral surfaces of via holes and through holes) can be easily roughened. Thereafter, copper plating or the like is performed on the surface of the insulating layer 6 to form a circuit to be an outer layer circuit, and copper holes or the like are formed in via holes or through holes to conduct the circuit of the circuit board 4 and the outer layer circuit. . Thereafter, by performing a surface treatment such as a solder resist, a multilayer printed wiring board can be formed by a build-up method.
Incidentally, before the solder resist is applied, the insulating layer 6 and the circuit on the surface thereof are sequentially formed in the same manner as described above, so that a multilayer printed wiring board can be finished.

The resin film 3 for producing a multilayer printed wiring board according to the present invention comprises a second layer 3b made of a thermosetting resin composition containing no rubber component and no inorganic filler.
Is formed on the insulating layer 6 by adhering to the surface of the circuit board and hardening it, so that the circuit 33 is subjected to a chemical treatment such as a blackening process in order to strengthen the adhesion between the insulating layer 6 and the circuit 33 of the circuit board 4. Even if it does, the resin component of the second layer 3b can be effectively spread to every corner of the circuit (the inner layer circuit) having the fine unevenness and coated, whereby the thickness of the insulating layer 6 (the Even if the total thickness of the first layer 3a and the second layer 3b is reduced, the insulation reliability can be maintained. In addition, since the surface of the insulating layer 6 is formed of the first layer 3a made of a thermosetting resin composition containing a rubber component soluble in alkali and an inorganic filler, the insulating layer 6 is coated with an alkaline oxidizing agent. The surface can be easily roughened, and the adhesion between the insulating layer 6 and the conductive layer is increased by the anchor effect by forming the conductive layer (circuit) on the roughened surface of the insulating layer 6. Can be done. In the insulating layer 6 formed of the resin film for manufacturing a multilayer printed wiring board according to the present invention, JIS
As a result of measuring the peel strength (adhesion strength) of the outer conductor layer by the method specified in C 6481, the insulating layer 6 was formed only with the thermosetting resin composition containing a rubber component and an inorganic filler as in the conventional example. The same adhesive strength (about 1.0 kN / m) as when formed is obtained, and the adhesion to the conductor layer is not impaired.

When a rubber component or an inorganic filler is contained in the second layer 3b as in the case of the first layer 3a, even if the rubber component or the inorganic filler is treated to make it compatible with the matrix of the resin component, Microcracks occur between the rubber component or the inorganic filler and the matrix, and these cracks occur around the irregularities of the circuit (inner circuit) 33 of the circuit board 4, which leads to deterioration of the insulation performance of the insulating layer 6 and multi-layering. The printed wiring board may fail various reliability tests. The second layer 3b may be formed by printing the thermosetting resin composition on the surface of the circuit board 4 by means such as printing, but it is better to laminate the first layer 3a and form a film by a single operation. The first layer 3a and the second layer 3b can be laminated on the circuit board 4, which is efficient.

[0042]

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

(Preparation of Thermosetting Resin Composition for Forming First Layer) A liquid brominated bisphenol A type epoxy resin ("YDF-8170" manufactured by Toto Kasei Co., Ltd.) and a brominated bisphenol A type epoxy resin ( "YDB made by Toto Kasei Co., Ltd.
-400 ") and terminal epoxidized polybutadiene rubber (" PB3600 "manufactured by Daisail Chemical Co., Ltd.) in the amounts shown in Table 1, and stirred while dissolving them in MEK.
Further, a phenol novolak type curing agent ("MEH-7500" manufactured by Meiwa Kasei Co., Ltd.) and spherical silica ("SFP-10X" manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 0.3 μm) were added to this solution.
m) was blended in the amounts shown in Table 1 to prepare a thermosetting resin composition for the first layer.

(Preparation of thermosetting resin composition for forming second layer) Same as the preparation of thermosetting resin composition for forming first layer described above except that spherical silica was not blended. Thus, a thermosetting resin composition of the second layer was prepared.

[0045]

[Table 1]

(Preparation of Resin Films of Examples 1 to 12 and Comparative Examples 1 to 30) A first-layer thermosetting resin composition was applied on a 38 μm-thick PET film (support) by a bar coater method. (Coating) and dried at 80 ° C. to form a first layer. Next, PET
The surface of the first layer formed on the film was coated (coated) with the second layer of the thermosetting resin composition by a bar coater method, and dried at 80 ° C. to form the second layer. Thus, a plurality of types of resin films having different thicknesses of the first layer and the second layer were produced. Table 2 shows the thickness of the first layer and the second layer. In addition, about Comparative Examples 25-30, the 2nd layer was not formed.

[0047]

[Table 2]

(Preparation of Multilayer Printed Wiring Board) A circuit forming step such as etching is performed on a copper foil of a copper-clad laminated board (“R1766T” thickness 1 mm, copper foil thickness 35 μm) manufactured by Matsushita Electric Works to form an inner layer circuit. A circuit was formed, and this was used as a circuit board 4 serving as an inner core material. The circuit formed here is J
This was used as a pattern for evaluating build-up interlayer insulation in the technical standard for build-up wiring boards of the IEP standard.

Next, a multilayer printed wiring board was formed in the same manner as described above. That is, the resin films of Examples 1 to 12 and Comparative Examples 1 to 24 were placed such that the second layer was in contact with the surface of the circuit board 4 on which the circuit was formed.
As for the circuit board 30, the first layer is in contact with the circuit board 4.
A resin film is placed on the surface of the substrate and molded at 110 ° C. and 0.1 MPa for 60 seconds using a vacuum laminator manufactured by Meiki Seisakusho, and then heated at 170 ° C. for 30 minutes using a dryer. Thus, the resin film 3 was cured to form the insulating layer 6 on the surface of the circuit board 4 to form a printed wiring board with an insulating layer. Next, via holes were formed in the insulating layer 6 by laser processing. Next, the surface of the insulating layer 6 is roughened by swelling treatment, permanganic acid treatment, and neutralization treatment with a desmear process device manufactured by Shipley Co., Ltd. After forming a copper plating having a thickness of 20 μm, a circuit was formed from the copper plating in a dry film process.

Examples 1 to 12 and Comparative Examples 1 to 3
12 pieces each of a multilayer printed wiring board using a resin film of No.
Under a constant temperature and humidity condition, a DC voltage of 50 V was applied between the outer layer circuit and the inner layer circuit to measure the insulation resistance. Thereafter, it broke off measurement is regarded insulation resistance defective when the insulation resistance became 10 ⁸ Omega. Then, the number of multilayer printed wiring boards whose insulation resistance became defective within a period of less than 1000 hours was measured.

Examples 1 to 12 and Comparative Examples 1 to 30
About the multilayer printed wiring board using the resin film of
The peel strength (adhesion strength) of the outer conductor layer was measured by the method specified in JIS C6481.

Table 3 shows the results.

[0053]

[Table 3]

As is clear from Table 3, Examples 1 to 12
Comparative Example 2 of multilayer printed wiring board using resin film
The insulation resistance was higher than that of a multilayer printed wiring board using 5 to 30 resin films (resin films on which the second layer was not formed), and the insulation reliability was excellent. Examples 3, 6, 9, and 10 in which the thickness of the second layer is less than 10 μm.
12 and Comparative Examples 3, 6, 9, 12, 15, 18, 21, 2
In No. 4, the insulation reliability was slightly lower than that of the other Examples and Comparative Examples in which the composition of the thermosetting resin composition of the second layer was the same. Further, the multilayer printed wiring boards using Examples 1 to 12 had an adhesion strength equal to or higher than that of the multilayer printed wiring boards using Comparative Examples 1 to 30. Therefore, the insulating layers formed by using Examples 1 to 12 are comparative examples 1 to 30.
As compared with the insulating layer formed by using the same, the insulation reliability is excellent without impairing the adhesion to the conductor layer.

[0055]

As described above, according to the first aspect of the present invention, an alkali-soluble rubber component and an inorganic filler are used in a resin film for producing a multilayer printed wiring board which is adhered to the surface of a circuit board by vacuum lamination. And a second layer made of a thermosetting resin composition containing no rubber component and no inorganic filler, so that the second layer is formed on the surface of the circuit board. By bonding the first layer and the second layer in a state of being bonded to form an insulating layer, the second layer made of a thermosetting resin composition containing no rubber component and no inorganic filler is bonded to the surface of the circuit board And cured to form an insulating layer, so even if the circuit is subjected to chemical treatment such as blackening to enhance the adhesion between the insulating layer and the circuit on the circuit board, fine irregularities Every corner of the circuit Thereby spread the resin component of the two-layer can be coated, but also by reducing the thickness can be formed an insulating layer excellent in insulation reliability.
Moreover, since the surface of the insulating layer is formed of the first layer made of a thermosetting resin composition containing a rubber component soluble in alkali and an inorganic filler, the surface of the insulating layer can be easily treated with an alkaline oxidizing agent. The surface can be roughened, and the adhesion between the insulating layer and the conductor layer can be increased by the anchor effect by forming the conductor layer on the surface of the roughened insulating layer. Therefore, the present invention can form an insulating layer having excellent insulation reliability without impairing the adhesion to the conductor layer.

Further, according to the invention of claim 2 of the present invention, since the thermosetting resin composition of the first layer contains 2 to 40% by mass of a rubber component and 2 to 20% by mass of an inorganic filler, respectively, And the adhesion between the conductive layer and the conductive layer can be further improved.

According to a third aspect of the present invention, the thickness of the first layer is 10 to 50 μm, and the thickness of the second layer is 10 to 30 μm.
m, the insulating reliability of the insulating layer can be further increased.

[Brief description of the drawings]

FIG. 1 shows an example of a manufacturing process of a multilayer printed wiring board using the present invention, and (a), (b) and (c) are cross-sectional views, respectively.

FIG. 2 is a schematic diagram showing a transport device according to the first embodiment;

FIG. 3A is a cross-sectional view showing a circuit board and a resin film, and FIG. 3B is a cross-sectional view showing a printed wiring board with an insulating layer.

[Explanation of symbols]

3 Resin film for manufacturing multilayer printed wiring boards 3a First layer 3b Second layer 4 Circuit board

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Shinya Nishimoto             1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd.             In the formula company F term (reference) 4F100 AA01A AA20 AG00A AK01A                       AK01B AK29 AK42 AK53                       AL05A BA02 BA25 CA02                       CA23 DE01 DE01A EH46                       EH462 EJ86 EJ862 GB43                       JB13A JB13B JG04 JL11                       YY00A                 5E346 AA02 AA12 CC04 CC08 CC09                       CC32 CC46 DD12 DD32 EE02                       EE35 FF03 FF04 GG27 GG28

Claims (3)

[Claims] 1. A resin film for producing a multilayer printed wiring board which is adhered to a surface of a circuit board by vacuum lamination, wherein a first layer comprising a thermosetting resin composition containing an alkali-soluble rubber component and an inorganic filler. And a second layer comprising a thermosetting resin composition containing no rubber component and no inorganic filler. 2. The multilayer according to claim 1, wherein the first layer of the thermosetting resin composition contains 2 to 40% by mass of a rubber component and 2 to 20% by mass of an inorganic filler. Resin film for manufacturing printed wiring boards. 3. The resin according to claim 1, wherein the first layer has a thickness of 10 to 50 μm and the second layer has a thickness of 10 to 30 μm. the film.