JPH09283932A - Multilayer printed wiring board manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board manufacturing method capable of roughening the inner walls of open holes for forming vias and surface of an interlayer insulation layer to provide an interlyer insulation layer superior indurability. SOLUTION: Hole forming posts 1 having a releasing agent at least ion their surface are disposed at via-forming positions on a first conductor circuit layer 51. An interlayer insulation layer 6 is formed on the surface of the first layer 51 with an exposed tops 17 of the posts 1. After removing the posts 1, an anchor-forming powder 4 is laid on the upper face of this layer 6, pressed and heated to bury the powder in the surface of the insulation layer 6 and inner walls of the open holes. The powder is removed to roughen the surface of the insulation layer 6 and inner walls of the holes and these surfaces are covered with a metal layer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a multilayer printed wiring board, which comprises manufacturing a multilayer printed wiring board by alternately laminating conductor circuit layers and interlayer insulating layers.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
There is a multilayer printed wiring board 9 in which 0s and interlayer insulating layers 93 are alternately built up. As a method of manufacturing the above-mentioned multilayer printed wiring board, there is a conventional method, for example, Japanese Patent Laid-Open No.
There is a method disclosed in Japanese Patent No. 2669.

That is, first, as shown in FIG. 13, a conductor circuit layer 90 is formed on the surface of an insulating substrate 91, and hole forming columns 92 for forming via holes are formed on the surface. Next, the surface of the insulating substrate 91 is covered with the interlayer insulating layer 93. Next, the interlayer insulating layer 93 covering the tops of the hole forming columns 92 is removed by buffing. Then, the conductor circuit layer 90 is removed to form an opening hole 95 reaching the conductor circuit layer 90 as shown in FIG.

Next, an interlayer insulating layer 93 is formed with an oxidizing agent or the like.
Surface roughening treatment is performed. As a result, only the filler contained in the interlayer insulating layer 93 is dissolved and the surface of the interlayer insulating layer 93 is roughened. Next, as shown in FIG. 15, a through hole 98 penetrating the insulating substrate 91 is formed. After that, the conductor circuit layer 96 is formed on the surface of the interlayer insulating layer 93, and the opening hole 9 is formed.
5. A metal layer 97 is formed on the inner wall surface of the through hole 98. Thereby, the multilayer printed wiring board 9 is obtained.

In this manufacturing method, since the hole forming pillar 92 is formed by exposing and developing the photosensitive resin layer, the hole forming accuracy is good. Further, by the surface roughening treatment of the interlayer insulating layer, fine recesses 930 are formed on the surface of the interlayer insulating layer 93 and the inner wall surface of the opening 95. The recess 930 enhances the anchor effect of the conductor circuit layer 96 and the metal layer 97, and improves the adhesion strength between them.

[0006]

However, in the conventional method for manufacturing a multilayer printed wiring board described above, when removing the hole forming pillars for forming the via holes, as shown in FIG.
The outer conductor 93 covering the top portion 927 as shown in FIG.
Must be removed by polishing. Although the polishing thickness is as thin as several tens of μm, the conductor circuit layer 90 on the insulating substrate 91 may be exposed or the wire may be broken unless it is polished in parallel. Therefore, a highly accurate parallel polishing device is required, resulting in high cost. Further, it is difficult to polish the upper surface of the interlayer insulating layer 93 in parallel to about several tens of μm.

By the surface roughening treatment of the interlayer insulating layer 93, the filler contained in the surface portion is removed, but the filler contained in the interlayer insulating layer 93 is not removed. Therefore, the multilayer printed wiring board is used while a large amount of the filler remains in the interlayer insulating layer 93. Then, when exposed to a harsh environment such as heating and cooling during use, the interlayer insulating layer 93 may deteriorate due to the difference in thermal expansion coefficient between the interlayer insulating layer 93 and the filler.

In view of the above conventional problems, the present invention can easily and inexpensively roughen the inner wall of the opening hole for forming a via hole and the surface of the interlayer insulating layer, and has excellent durability of the interlayer insulating layer. Another object is to provide a method for manufacturing a multilayer printed wiring board.

[0009]

According to a first aspect of the present invention, when a conductive circuit layer and an interlayer insulating layer are alternately built up on an insulating substrate to manufacture a multilayer printed wiring board having a via hole, the insulation is provided. Forming a first conductor circuit layer on the substrate,
Next, a hole forming column containing a release agent on at least the surface is arranged at a via hole forming position in the first conductor circuit layer, and then the hole forming column is exposed with the top of the hole forming column exposed. The interlayer insulating layer is formed on the surface of the first conductor circuit layer so as to surround the side wall of the forming pillar, and then the hole forming pillar is removed to form an opening hole reaching the first conductor circuit layer. Then, the anchor forming powder is placed on the upper surface of the interlayer insulating layer and in the opening hole, and then pressed and heated to embed the anchor forming powder on the surface of the interlayer insulating layer and the inner wall surface of the opening hole. Then, the anchor forming powder is dissolved and removed using a solvent to make the surface of the interlayer insulating layer a roughened surface and the inner wall surface of the opening hole to be a roughened inner wall surface.
Thereafter, the roughened surface of the interlayer insulating layer and the roughened inner wall surface of the opening hole are covered with a metal layer to form a second conductor circuit layer and a via hole, which is a method for manufacturing a multilayer printed wiring board. .

What is most noticeable in the present invention is that the interlayer insulating layer is formed on the surface of the first conductor circuit layer so as to surround the side wall of the hole forming pillar, and after the hole forming pillar is removed. This is to roughen the inner wall surface of the opening hole and the surface of the interlayer insulating layer by arranging the anchor forming powder in the opening hole which is the escape trace and on the surface of the interlayer insulating layer and pressing and heating.

Next, the function and effect of the present invention will be described. In the method for manufacturing a multilayer printed wiring board according to the present invention, the interlayer insulating layer is formed on the surface of the first conductor circuit layer so as to surround the side wall of the hole-forming pillar. Therefore, the top of the hole forming pillar is not covered with the interlayer insulating layer and is exposed. Therefore, the hole forming pillars can be removed without polishing the interlayer insulating layer, which facilitates the production of the multilayer printed wiring board.

Further, anchor forming powder is embedded in the inner wall of the opening hole and the surface of the interlayer insulating layer, which are the traces of the hole forming pillar removed, and then the anchor forming powder is dissolved and removed. Therefore, a roughened surface is formed in the opening hole and a roughened surface is formed in the interlayer insulating layer, and no anchor forming powder remains on these surfaces. Also, no foreign matter exists inside the interlayer insulating layer. Therefore, the interlayer insulating layer does not deteriorate due to the difference in thermal expansion from the foreign matter, and has excellent durability.

Further, anchor forming powder is arranged on the surface of the interlayer insulating layer and the inner wall of the opening hole, and the powder is pressed,
It is heating. Therefore, the anchor forming powder is embedded in the surface of the interlayer insulating layer and the inner wall of the opening hole with a uniform thickness. Therefore, by removing the anchor forming powder, a roughened surface is uniformly formed on the surface of the interlayer insulating layer, and a roughened inner wall surface is uniformly formed on the inner wall surface of the opening hole.

Therefore, a uniform adhesion can be obtained by the anchor effect between the roughened surface of the interlayer insulating layer and the metal layer, and between the roughened inner wall surface of the opening hole and the metal layer, and the metal layer is formed. There is no risk of peeling. Further, unlike the conventional case, the parallel polishing apparatus is not required, so that the multilayer printed wiring board can be manufactured at low cost.

Further, it is preferable that the hole forming column is made of a photosensitive resin. As a result, by exposing and developing the photosensitive resin, the forming accuracy of the hole forming columns is good. Therefore, even a via hole having a small diameter of about 0.1 mm can be accurately formed.

Further, the hole forming column contains a release agent at least on its surface. The release agent is preferably mixed in the hole forming column. As a result, the hole forming column as a whole exhibits excellent releasability from the interlayer insulating layer, the hole forming column is easily removed from the interlayer insulating layer, and the opening hole is not damaged. In addition, a mold release agent can be contained on the surface of the hole forming column at the same time when the hole forming column is formed, which facilitates the production of the hole forming column. Further, the release agent may be applied to the surface of the hole forming column. As a result, the amount of release agent used can be reduced.

The release agent is preferably a fluorine-based release agent. As a result, the hole forming pillar is more easily peeled from the wall surface of the opening hole, and the hole forming pillar is easily removed. Examples of the fluorine-based releasing agent include anionic, cationic, nonionic, or amphoteric fluorosurfactants and low molecular weight tetrafluoroethylene resins. These release agents further improve the slipperiness of the surface of the hole forming column.

Examples of the above-mentioned anionic fluorine-based surfactant include fluoroalkoxy polyfluoroalkyl sulfate, fluorocarbon sulfonate, fluorocarbon carboxylate and the like. Examples of the above-mentioned cationic fluorosurfactants include N-fluoroalkylsulfonamidoalkylamine quaternary ammonium salts and N-fluoroalkylsulfonamidoalkylamine salts.

Examples of the nonionic surfactants include fluorocarbon sulfamide and fluorocarbon aminosulfoamide. Examples of the amphoteric fluorine-based surfactant include alkylamines having a betaine-type fluorocarbon sulfamide bond and alkylamines having a betaine-type fluorocarbon acid amide bond.

It is preferable that the solvent is an oxidizing agent and the anchor forming powder is a powder that can be dissolved by the oxidizing agent. This facilitates dissolution and removal of the anchor-forming powder, and there is no risk of the anchor-forming powder remaining on the roughened surface of the interlayer insulating layer. As the anchor forming powder, for example, calcium carbonate fine powder, epoxy resin fine powder, copper fine powder, silica ultrafine powder, or the like can be used. Examples of the oxidizing agent include chromic acid and hydrochloric acid.

Further, as described in claim 2, when arranging the hole forming columns, a cavity forming member containing a release agent on at least a surface and forming a recess for mounting electronic parts, It is preferable that the cavity forming member is disposed at a position where the electronic component mounting recess is formed, and the cavity forming member is removed after the metal layer is formed. This makes it possible to easily form the recess for mounting an electronic component on the multilayer printed wiring board.
Further, since the surface of the cavity forming member contains the release agent, it is easy to remove the cavity forming member from the recess for mounting electronic parts. In addition, the recess for mounting electronic parts has a good finish.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a multilayer printed wiring board according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the multilayer printed wiring board 8 manufactured according to the present example is one in which first conductor circuit layers 51, interlayer insulating layers 6 and second conductor circuit layers 52 are alternately built up on an insulating substrate 3. Is. The interlayer insulating layer 6 is provided with a via hole 53 reaching the first conductor circuit layer 51. Further, the inter-layer insulating layer 6 is provided with an electronic component mounting recess 65 for mounting an electronic component.

Next, a method for manufacturing the above-mentioned multilayer printed wiring board will be described with reference to FIGS. First, FIG.
As shown in FIG. 1, the first conductor circuit layer 51 is formed on the surface of the insulating substrate 3.
To form As the insulating substrate 3, for example, a resin substrate such as glass epoxy is used. The first conductor circuit layer 51 is formed by a subtractive method using copper foil or the like.
Next, as shown in FIG. 3, the hole forming pillar 1 is arranged at the via hole forming position in the first conductor circuit layer 51.

As shown in FIG. 11, the hole forming column 1 is a cylinder having a smooth surface 10 and a diameter of 0.2 mm. The hole forming pillar 1 is formed by supplying a mixture of a photosensitive resin such as an acrylic resin and a release agent onto the insulating substrate 3 and exposing and developing the mixture. A low molecular weight tetrafluoroethylene resin is used as a release agent.

Further, as shown in FIG. 3, the cavity forming member 2 for forming the electronic component mounting recess is arranged at the position where the electronic component mounting recess is formed on the insulating substrate 3. As shown in FIG. 12, the cavity forming member 2 was processed into a shape of a recess for mounting electronic parts by using a heat-resistant re-peeling film NT75 (trade name, manufactured by Panac Co., about 75 μm) having a release agent 230. It is a thing.

Then, as shown in FIG. 4, the first conductor circuit layer 51 is formed so as to surround the side wall of the hole forming pillar 1.
The interlayer insulating layer 6 is formed on the surface of the. The top portion 17 of the hole forming column 1 is projected from the surface of the interlayer insulating layer 6.

In forming the interlayer insulating layer 6, a raw material consisting of 100 parts by weight of a phenol novolac type epoxy resin and 5 parts by weight of imidazole is kneaded, and 10% by weight of butyl cellosolve acetate is added. After stirring this mixture with a homodisbar, 3
Knead with this roller. This resin kneaded material is applied and cured on the entire surface of the insulating substrate 3. At this time, the tops 17 of the hole forming columns 1 are exposed.

Next, as shown in FIG. 5, the hole forming pillar 1 is removed, and the first conductor circuit layer 51 is formed on the interlayer insulating layer 6.
An opening hole 60 reaching to In removing the hole forming pillar 1, while applying ultrasonic vibration, the insulating substrate 3 is immersed in a photosensitive resin solution (methyl chloride solution)
Soak for a minute. As a result, the hole forming pillar is removed, and the opening hole 60 having an inner diameter of 0.2 mm is formed.

Next, as shown in FIG. 6, the interlayer insulating layer 6
The anchor forming powder 4 is placed on the upper surface and the opening hole of the, and pressed by the pressing plate 45 from above and heated.
As a result, the interlayer insulating layer 6 is softened and the anchor forming powder 4 is embedded in the surface of the interlayer insulating layer 6.

The anchor forming powder 4 is a fine powder of calcium carbonate which can be dissolved by a solvent. Then, as shown in FIG. 7, after removing the pressing plate 45, the interlayer insulating layer 6 is removed.
The anchor-forming powder 4 not buried in is removed.

Next, the insulating substrate 3 is immersed in an aqueous solution of hydrochloric acid which is a solvent. As a result, the anchor forming powder 4 is dissolved and removed to form a roughened surface 62 on the interlayer insulating layer 6 and a roughened inner wall surface 61 of the opening hole 60, as shown in FIG. If necessary, a through hole for forming a through through hole is formed in the roughened insulating substrate by a drill or the like.

Then, as shown in FIG. 9, a photosensitive resin is applied by a screen printing method, and a portion of the surface of the interlayer insulating layer 6 where the second conductor circuit layer is not formed is exposed and cured, thereby electroless A resist film 7 for plating is formed. Next, the insulating substrate 3 is treated with a palladium-tin colloidal catalyst solution to form catalyst nuclei on the non-resist forming portion of the interlayer insulating layer 6.

Then, as shown in FIG. 10, on the roughened surface 62 of the interlayer insulating layer 6 and the roughened inner wall surface 61 of the opening hole 60,
The metal layer 5 is formed by the electroless copper plating method. As a result, the second conductor circuit layer 52 is formed on the surface of the interlayer insulating layer 6,
A via hole 53 is formed in the opening hole 60. The metal layer 5 can be formed by sputtering, vapor deposition, or paste application, in addition to the plating method. Then, the cavity forming member 2 and the photosensitive resist film 7 are removed if unnecessary. As described above, the multilayer printed wiring board 8 shown in FIG. 1 is obtained.

Next, the function and effect of this example will be described.
In this example, as shown in FIG.
An interlayer insulating layer 6 is formed on the surface of the hole forming column 1 so as to surround the side wall of the hole forming column 1. Therefore, the top portion 17 of the hole forming pillar 1 is not covered with the interlayer insulating layer 6,
Exposed. Therefore, without polishing the interlayer insulating layer 6,
The hole forming pillar 1 can be removed.

As shown in FIG. 7, the anchor forming powder 4 is embedded in the inner wall of the opening hole 60, which is a trace of the hole forming pillar, and the surface of the interlayer insulating layer 6, and then the anchor forming powder 4 is formed. The powder 4 is dissolved and removed. Therefore, as shown in FIG.
However, a roughened surface 62 is formed on the interlayer insulating layer 6, and no anchor forming powder remains on these surfaces.

Also, no foreign matter such as anchor forming powder exists inside the interlayer insulating layer 6. Therefore, the interlayer insulating layer 6 does not deteriorate due to the difference in thermal expansion with the foreign matter,
Has excellent durability. Moreover, it is possible to use the calcium carbonate fine powder, which has a problem of moisture resistance due to the inclusion thereof, at a very low price, as the anchor forming powder 4.

Further, as shown in FIG. 6, the anchor forming powder 4 is arranged on the surface of the interlayer insulating layer 6 and the inner wall of the opening hole 60, and this is pressed and heated. for that reason,
The anchor forming powder 4 is embedded in the surface of the interlayer insulating layer 6 and the inner wall of the opening hole 60 with a uniform thickness. Therefore, as shown in FIG. 7, by removing the anchor forming powder, a roughened surface 62 and an opening hole 60 are formed on the surface of the interlayer insulating layer 6.
A roughened inner wall surface 61 is formed on the inner wall of the plate with a uniform thickness.

Therefore, as shown in FIG. 10, by the anchor effect, between the roughened surface 62 of the interlayer insulating layer 6 and the metal layer 5, and between the roughened inner wall surface 61 of the opening 60 and the metal layer 5. , Uniform adhesion can be obtained and peeling of the metal layer can be prevented. Further, since the parallel polishing apparatus as in the prior art is not required, the multilayer printed wiring board 8 can be manufactured at low cost.

[0039]

According to the present invention, the inner wall of the opening hole for forming the via hole and the surface of the interlayer insulating layer can be roughened easily and at low cost, and the durability of the interlayer insulating layer is excellent.
A method for manufacturing a multilayer printed wiring board can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multilayer printed wiring board according to an exemplary embodiment.

FIG. 2 is an explanatory diagram of an insulating substrate on which a first conductor circuit layer is formed in the embodiment example.

FIG. 3 is an explanatory view of an insulating substrate on which a hole forming column and a cavity forming member are arranged in the embodiment example.

FIG. 4 is an explanatory diagram of an insulating substrate having an interlayer insulating layer formed on the surface according to the embodiment.

FIG. 5 is an explanatory view of an insulating substrate from which a hole forming pillar is removed in the embodiment.

FIG. 6 is an explanatory view showing a method of pressing and heating anchor forming powder in the embodiment.

FIG. 7 is an explanatory view showing an interlayer insulating layer in which anchor forming powder is embedded, in an embodiment example.

FIG. 8 is an explanatory view showing an interlayer insulating layer having a roughened surface and an opening hole having a roughened inner wall surface in the embodiment.

FIG. 9 is an explanatory diagram of an interlayer insulating layer having a resist film formed on the surface in the embodiment.

FIG. 10 is an explanatory diagram of an interlayer insulating layer coated with a metal layer in the embodiment example.

FIG. 11 is a perspective view of a hole forming column according to the embodiment.

FIG. 12 is an explanatory view showing a cavity forming member in which a release agent is mixed in the embodiment example.

FIG. 13 is an explanatory view showing a problem in a method for manufacturing a multilayer printed wiring board in a conventional example.

FIG. 14 is an explanatory diagram of a roughened insulating substrate in a conventional example.

FIG. 15 is a cross-sectional view of a multilayer printed wiring board in a conventional example.

[Explanation of symbols]

 1,…, Hole forming columns, 10. . . Smooth surface, 230. . . Release agent, 2. . . Cavity forming member, 3. . . Insulating substrate, 51. . . First conductor circuit layer, 52. . . Second conductor circuit layer, 53. . . Via hole, 6. . . Interlayer insulating layer, 60. . . Opening hole, 61. . . Roughened inner wall surface, 62. . . Roughened surface, 7. . . Resist film, 8. . . Multilayer printed wiring board,

Claims (2)

[Claims] 1. When manufacturing a multilayer printed wiring board having via holes by alternately building up conductor circuit layers and interlayer insulating layers on an insulating substrate, forming a first conductor circuit layer on the insulating substrate. Then, a hole forming column containing a release agent on at least the surface thereof is arranged at a via hole forming position in the first conductor circuit layer, and then, with the top of the hole forming column exposed, The interlayer insulating layer is formed on the surface of the first conductor circuit layer so as to surround the side wall of the hole forming pillar, and then the hole forming pillar is removed to form an opening hole reaching the first conductor circuit layer. Then, the anchor forming powder is placed on the upper surface of the interlayer insulating layer and in the opening hole, and then pressed and heated to apply the anchor forming powder to the surface of the interlayer insulating layer and the inner wall surface of the opening hole. By embedding in the substrate, and then dissolving and removing the anchor-forming powder with a solvent to form the surface of the interlayer insulating layer as a roughened surface and the inner wall surface of the opening hole as a roughened inner wall surface, and thereafter, The roughened surface of the interlayer insulating layer and the roughened inner wall surface of the opening hole are covered with a metal layer,
A method of manufacturing a multilayer printed wiring board, which comprises forming a conductor circuit layer and a via hole. 2. The electronic component mounting method according to claim 1, further comprising a cavity forming member containing a mold release agent on at least a surface of the hole forming column when forming the hole forming column and forming a concave portion for electronic component mounting. A method for manufacturing a multilayer printed wiring board, characterized in that the cavity forming member is disposed at a formation position of a concave portion, and the cavity forming member is removed after the metal layer is formed.