JP2013080836A - Manufacturing method of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a printed wiring board whose position tolerance of a laser via and a circuit pattern is small.SOLUTION: Since a resist film 54 is formed on the basis of a recess 60bh of an opening 51b for positioning formed simultaneously with an opening 51d for a via by laser, a positional accuracy of a conductor circuit 58 formed by the resist film 54, and a filled via 60 formed at the opening 51d for a via, is high and wiring of a fine pitch can be formed.

Description

The present invention relates to a method for manufacturing a printed wiring board in which an interlayer insulating layer is laminated on a substrate and laser vias and circuit patterns are formed.

Patent Document 1 discloses a manufacturing method based on a through-hole using an X-ray image processing type posa hole processing machine as a method for aligning a laser via with an inner bottom land. In the manufacturing method, the circuit pattern on the via is aligned using the reference hole.

JP 2003-318535 A

However, in the manufacturing method of the prior art, laser processing is performed with reference to the through hole formed for alignment, a laser via is formed, the laser via is plated and filled, a via conductor is formed, and the resist is exposed with reference to the through hole. The circuit pattern is formed by developing and etching, and the via conductor formed in the laser via and the circuit pattern are indirectly aligned on the basis of the through hole, so the alignment tolerance increases and the fine pitch It was difficult to form a circuit pattern.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a printed wiring board having a small positional tolerance between a laser via and a circuit pattern.

The method for manufacturing a printed wiring board according to claim 1 comprises preparing a substrate having a conductor layer;
Forming an interlayer insulating layer on the substrate;
Forming a via opening extending through the interlayer insulating layer to the conductor layer with a laser and a positioning opening having a larger diameter than the via opening;
Forming a conductor having a recess in the positioning opening by plating;
Forming a resist film having a predetermined pattern on the formed plating with the position of the concave portion as a reference.

The printed wiring board manufacturing method according to claim 1, wherein the resist film is formed on the basis of the concave portion of the positioning opening formed simultaneously with the via opening by the laser, so that the conductor circuit formed by the resist film and the via opening are formed. Therefore, a fine pitch wiring can be formed with a high positional accuracy with respect to the via formed in the above.

In the method for manufacturing a printed wiring board according to claim 2, a resist film is formed on the basis of a concave portion of a positioning opening formed simultaneously with a via opening by a laser. Therefore, a conductor circuit formed by the resist film and a via opening are formed. A fine pitch wiring can be formed with high positional accuracy with the filled via.

In the printed wiring board manufacturing method according to claim 3, the diameter of the positioning opening is set to be 1.5 times or more the diameter of the via opening, so that the filled via is formed in the via opening and the positioning opening is formed. A plating with a recess can be formed.

In the method for manufacturing a printed wiring board according to the fourth aspect, the dummy via conductor having a recess is formed in the positioning opening, whereby the positioning can be performed using the recess.

In the method for manufacturing a printed wiring board according to claim 5, even when an uncured photosensitive resist film is applied on the upper side by forming the depth of the recess to 30 to 150 μm, the recess is filled with the resist film. In addition, the position of the recess can be detected optically through the photosensitive resist film.

In the printed wiring board manufacturing method according to the sixth aspect, since the interlayer insulating layer is formed from the prepreg formed by impregnating the core material with the resin, the interlayer insulating layer has strength.

In the method for manufacturing a printed wiring board according to the seventh aspect, since the metal foil is formed on the interlayer insulating layer, the via opening having a desired shape can be formed with a laser.

In the printed wiring board manufacturing method according to the eighth aspect, since the metal foil is thinned after being laminated, the metal foil has a thickness before lamination, and the metal foil is easy to handle. After the lamination, the metal foil is thinned in advance, so that a via opening having a desired shape can be formed with a laser.

In the printed wiring board manufacturing method according to the ninth aspect, the plurality of positioning openings are arranged in a predetermined pattern such as an annular shape, a cross shape, or a rectangular shape. For example, since a plurality of positioning openings are formed in a ring shape, the center coordinates of the approximate circle can be accurately calculated even if several positioning openings cannot be detected.

The method for manufacturing a printed wiring board according to claim 10, wherein the resist film is formed in a predetermined pattern by forming a photosensitive resist film on the plating, exposing with reference to a concave portion under the photosensitive resist film, and developing. . Since the concave portion reflects light received from the upper surface, the concave portion under the photosensitive resist film can be accurately recognized.

In the printed wiring board manufacturing method according to the eleventh aspect, the via opening and the positioning opening formed by the laser are formed in advance on the substrate by forming the positioning mark and using the positioning mark as a reference, and therefore can be formed accurately. .

In the printed wiring board manufacturing method according to claim 12, since the circuit pattern is formed by removing the plating of the non-formed portion of the resist film formed on the basis of the recess, the filled via formed simultaneously with the recess, and the circuit pattern High positional accuracy.

In the method for manufacturing a printed wiring board according to claim 13, when forming the opening with a laser, a hole having a spot diameter is formed in a spot shape instead of scanning (trepanning), so that the core material of the interlayer insulating layer is formed in the opening. The via opening and the positioning opening can be formed in a desired shape without being easily exposed.

It is process drawing of the manufacturing method of the printed wiring board which concerns on 1st Embodiment of this invention. It is process drawing of the manufacturing method of the printed wiring board which concerns on 1st Embodiment. It is process drawing of the manufacturing method of the printed wiring board which concerns on 1st Embodiment. It is process drawing of the manufacturing method of the printed wiring board which concerns on 2nd Embodiment. It is process drawing of the manufacturing method of the printed wiring board which concerns on 2nd Embodiment. It is process drawing of the manufacturing method of the printed wiring board which concerns on 2nd Embodiment. It is a top view which shows arrangement | positioning of the recessed part for positioning. It is sectional drawing of the printed wiring board which concerns on 2nd Embodiment of this invention.

[First embodiment]
FIG. 3B is a cross-sectional view of the printed wiring board according to the manufacturing method of the first embodiment.
In the printed wiring board 10, an interlayer insulating layer 50 is laminated on the core substrate 30. On the surface of the core substrate 30, a reference land 34a, a positioning land 34b, a wiring line 34c, and a via land 34d are formed. A dummy via 60b having a positioning recess 60bh is formed on the positioning land 34b, and a filled via 60 is formed on the via land 34d. A conductor circuit 58 is formed on the interlayer insulating layer 50.

A method for manufacturing the printed wiring board shown in FIG. 3B is shown in FIGS.
(1) The copper foil of the copper clad laminate on which the copper foil is laminated is patterned to form the reference land 34a, the positioning land 34b, the wiring line 34c, and the via land 34d on the insulating substrate, and the core substrate 30 is prepared. (FIG. 1 (A)). The insulating substrate is made of a reinforcing material such as glass cloth, aramid fiber, or glass fiber and a resin such as epoxy resin or BT (bismaleimide triazine) resin. Although not shown, a through-hole conductor penetrating the front and back of the core substrate is formed.

(2) A 60 μm thick interlayer insulating layer 50 made of a prepreg obtained by impregnating a glass cloth with an epoxy resin and a 20 μm thick copper foil 48 are laminated on the core substrate 30 (FIG. 1B). Then, the thickness of the copper foil is reduced to 5 μm by light etching (FIG. 1C), and the blackening process is performed on the surface of the copper foil to form a blackened film 48γ (FIG. 1D). In addition, you may use 5 micrometers copper foil as it is, without etching.

(3) The periphery of the reference land 34a on the core substrate is excavated with a CO2 laser, an opening 50a is formed in the interlayer insulating layer 50, and the reference land 34a is exposed (FIG. 1E).

(4) The reference land 34a is imaged by the camera 82A, and a positioning opening 51b is simultaneously formed on the positioning land 34b and a via opening 51d is formed on the via land 34d with the laser using the reference land 34a as a reference (see FIG. 2 (A)). The via opening 51d is formed with an opening top diameter Dd of 60 μm and an opening bottom diameter dd of 55 μm, and the positioning opening 51b is formed with an opening top diameter of Db of 100 μm and an opening bottom diameter of db of 95 μm (FIG. 2B). The opening diameter is not particularly limited to the top diameter and the bottom diameter, but the maximum diameters of the respective openings are compared. The term “simultaneous” here means that the aperture is formed by sequentially irradiating the laser with the same laser device while being positioned by the reference land 34a.

(5) An electroless copper plating film 52 is formed on the copper foil 48 and in the opening 50a, the positioning opening 51b, and the via opening 51d (FIG. 2C). Subsequently, the electrolytic copper plating film 56 is formed by electrolytic plating. The filled via 60 is formed in the via opening 51d, and the dummy via 60b including the positioning recess 60bh is formed in the positioning opening 51b (FIG. 2D). The depth hh of the recess 60bh is 50 μm. Here, by setting the opening diameter of the positioning opening 51b to 1.5 times or more the opening diameter of the via opening 51d, the recessed via 60bh is provided when the filled via 60 is completed in the via opening 51d by the same electrolytic plating. A dummy via 60b can be formed.

(6) An uncured photosensitive etching resist film 54α is placed on the electrolytic plating 56, passes through the photosensitive etching resist film 54α by the camera 82B, and the positioning recess 60bh is imaged from above, and the positioning recess The alignment is performed based on 60 bh, and the photosensitive etching resist film 54α is exposed (cured) by a laser (FIG. 2E). In addition to the laser, exposure by a mask method is also possible.

(7) The uncured photosensitive etching resist film is developed and removed to form an etching resist film 54 having a predetermined pattern (FIG. 3A)).

(8) The electrolytic plating 56, the electroless plating film 52, and the copper foil 48 in the portion where the etching resist film 54 is not formed are removed, the via land 60R and the conductor circuit 58 are formed, the etching resist film is removed, and the printed wiring board 10 is formed. Completed (FIG. 3B).

FIG. 7 shows the formation position of the positioning recess 60bh of the first embodiment.
In the example shown in FIG. 7A, since the positioning openings 60bh are formed in a ring shape, the center coordinate Z of the approximate circle can be accurately calculated even if some positioning openings cannot be detected. Here, the positioning openings can be arranged in a cross shape as shown in FIG. 7 (B) or in a matrix shape as shown in FIG. 7 (C).

FIG. 3C is an enlarged view of the dummy via 60b including the positioning recess 60bh. The dummy via 60b includes a side wall 60bw along the opening 51b and a flat bottom 60bb along the positioning land 34b. If the bottom 60bb is not flat (there is unevenness), a shadow is formed and the imaging sensitivity becomes dull. Therefore, if the bottom is flat, the positioning recess 60bh can be clearly imaged through the photosensitive etching resist film 54α with the camera 82B.

The depth hh of the positioning recess 60bh is preferably 30 to 150 μm. When the thickness is less than 30 μm, the uncured photosensitive resist film follows the concave portion, and the imaging sensitivity becomes low. By setting the thickness to 30 μm or more, even when an uncured photosensitive resist film is applied on the upper side, the concave portion is not filled with the resist film, and the position of the concave portion is optically detected through the photosensitive resist film. be able to. On the other hand, if it is formed to a depth of more than 150 μm, the reflected light from the bottom surface becomes small, so that the imaging sensitivity becomes dull.

In the method of manufacturing the printed wiring board according to the first embodiment, the resist film 54 is formed on the basis of the recess 60bh of the positioning opening 51b formed simultaneously with the via opening 51d by a laser. Position accuracy between the circuit 58 and the filled via 60 formed in the via opening 51d is high, and a fine pitch wiring can be formed.

In the method for manufacturing a printed wiring board according to the first embodiment, since the interlayer insulating layer 50 is formed from a prepreg formed by impregnating a core material with a resin, the interlayer insulating layer has strength.

In the printed wiring board manufacturing method of the first embodiment, since the metal foil 48 is laminated on the interlayer insulating layer 50, a via opening having a desired shape can be formed with a laser.

In the printed wiring board manufacturing method of the first embodiment, since the metal foil 48 is thinned after being laminated, the metal foil 48 has a thickness before lamination and is easy to handle. After the lamination, the metal foil is thinned in advance, so that a via opening having a desired shape can be formed with a laser.

In the method for manufacturing a printed wiring board according to the first embodiment, a photosensitive resist film 54α is placed on a plating, exposed with reference to a positioning recess 60bh below the photosensitive resist film, and developed into a predetermined pattern. A resist 54 is formed. Since the positioning recess 60bh reflects light received from the upper surface, the positioning recess 60bh below the photosensitive resist film can be accurately recognized.

In the method for manufacturing a printed wiring board according to the first embodiment, the via opening 51d and the positioning opening 51b by the laser are formed on the core substrate 30 in advance with the reference land 34a, and the reference land 34a is used as a reference. It can be formed accurately.

In the method for manufacturing a printed wiring board according to the first embodiment, it is desirable to form a hole having a spot diameter of the laser in a spot shape instead of scanning (trepanning) when forming the opening with a laser. Even when an interlayer insulating layer including a core material is used, the core material of the interlayer insulating layer is hardly exposed in the opening, and the via opening and the positioning opening can be formed in a desired shape.

[Second Embodiment]
FIG. 6 shows a cross-sectional view of a printed wiring board according to the manufacturing method of the second embodiment.
In the printed wiring board 10, an interlayer insulating layer 50 is laminated on the core substrate 30. On the surface of the core substrate 30, a reference land 34a, a positioning land 34b, a wiring line 34c, and a via land 34d are formed. A dummy via 60b having a recess 60bh is formed on the positioning land 34b, and a filled via 60 is formed on the via land 34d. A conductor circuit 58 is formed on the interlayer insulating layer 50.

A method of manufacturing the printed wiring board shown in FIG. 6 is shown in FIGS.
(1) The copper foil of the copper clad laminate on which the copper foil is laminated is patterned to form the reference land 34a, the positioning land 34b, the wiring line 34c, and the via land 34d on the insulating substrate, and the core substrate 30 is prepared. (FIG. 4 (A)).

(2) A 60 μm thick interlayer insulating layer 50 made of a prepreg in which a glass cloth is impregnated with an epoxy resin and a 10 μm thick copper foil 48 are laminated on the core substrate 30 (FIG. 4B). Then, a blackening process is performed on the surface of the copper foil to form a blackened film 48γ (FIG. 4C).

(3) The opening 48a of the copper foil 48 is formed on the upper portion of the reference land 34a by laser (FIG. 4D).

(4) The reference land 34a is imaged by the camera 82A, and a positioning opening 51b is simultaneously formed on the positioning land 34b and a via opening 51d is formed on the via land 34d with the laser using the reference land 34a as a reference (see FIG. 4 (E), FIG. 5 (A)).

(5) Electroless copper plating film 52 is formed on copper foil 48, interlayer insulating layer 50, and in positioning openings 51b and via openings 51d (FIG. 5B).

(6) An uncured photosensitive plating resist film 57α is placed on the electroless copper plating film 52, passes through the photosensitive plating resist film 57α by the camera 82B, and is electroless in the positioning opening 51b from above. The plated film is imaged, aligned based on the positioning opening 51b, and the photosensitive plating resist film 57α is exposed (cured) by a laser (FIG. 5C).

(7) The uncured photosensitive plating resist film is developed and removed to form a predetermined pattern of plating resist 57 (FIG. 5D).

(8) The electrolytic copper plating film 56 is formed in the plating resist non-forming portion by electrolytic plating, the filled via 60 is formed in the via opening 51d, and the dummy via 60b having the recess 60bh is formed in the positioning opening 51b (FIG. 5 (E)).

(9) The plating resist is peeled off, the electroless plating film 52 and the copper foil 48 under the plating resist are removed, the via land 60R and the conductor circuit 58 are formed, and the printed wiring board 10 according to the manufacturing method of the second embodiment is formed. Completed (FIG. 6).

[Second Embodiment]
FIG. 8 is a cross-sectional view of a printed wiring board according to the second embodiment.
In the printed wiring board 10, interlayer insulating layers 50A, 50C, 50E, 50G, and 50I are laminated on the first surface F side of the core insulating layer 50M disposed in the center, and the interlayer insulating layer 50B on the second surface S side. 50D, 50F, 50H, and 50J are laminated. The conductor circuit 58Ma on the first surface F and the conductor circuit 58Mb on the second surface S of the core insulating layer 50M are connected via a via conductor 60M.

In the interlayer insulating layer 50A stacked on the first surface F side of the core insulating layer 50M, a via conductor 60A for connecting the conductor circuit 58A on the interlayer insulating layer 50A to the conductor circuit 58Ma of the core insulating layer 50M is provided. Is formed. Via conductor 60C for connecting conductor circuit 58C on interlayer insulating layer 50C to conductor circuit 58A on interlayer insulating layer 50A is formed in interlayer insulating layer 50C laminated on interlayer insulating layer 50A. Yes. A via conductor 60E that connects the conductor circuit 58E on the interlayer insulation layer 50E to the conductor circuit 58C on the interlayer insulation layer 50C is formed in the interlayer insulation layer 50E laminated on the interlayer insulation layer 50C. A via conductor 60G for connecting the conductor circuit 58G on the interlayer insulating layer 50G to the conductor circuit 58E on the interlayer insulating layer 50E is formed in the interlayer insulating layer 50G laminated on the interlayer insulating layer 50E. Yes. Via conductor 60I for connecting conductor circuit 58I on interlayer insulating layer 50I to conductor circuit 58G on interlayer insulating layer 50G is formed in interlayer insulating layer 50I stacked on interlayer insulating layer 50G. Yes.

In the interlayer insulating layer 50B stacked on the second surface S side of the core insulating layer 50M, a via conductor 60B for connecting the conductor circuit 58B on the interlayer insulating layer 50B to the conductor circuit 58Mb of the core insulating layer 50M is provided. Is formed. A via conductor 60D for connecting the conductor circuit 58D on the interlayer insulation layer 50D to the conductor circuit 58B on the interlayer insulation layer 50B is formed on the interlayer insulation layer 50D laminated on the interlayer insulation layer 50B. Yes. A via conductor 60F that connects the conductor circuit 58F on the interlayer insulation layer 50F to the conductor circuit 58D on the interlayer insulation layer 50D is formed in the interlayer insulation layer 50F stacked on the interlayer insulation layer 50D. Via conductor 60H for connecting conductor circuit 58H on interlayer insulating layer 50H to conductor circuit 58F on interlayer insulating layer 50F is formed in interlayer insulating layer 50H laminated on interlayer insulating layer 50F. Yes. Via conductor 60J for connecting conductor circuit 58J on interlayer insulating layer 50J to conductor circuit 58H on interlayer insulating layer 50H is formed in interlayer insulating layer 50J laminated on interlayer insulating layer 50H. Yes.

In the printed wiring board of the second embodiment, the core insulating layer 50M and the interlayer insulating layers 50A to 50J are made of an epoxy resin including an inorganic filler including a glass cloth core material.

In the second embodiment, only the dummy via 60b of the interlayer insulating layer 50I is shown in the drawing. However, as in the first embodiment, the via conductor and the conductor circuit of the core insulating layer and the interlayer insulating layer are provided with the positioning recess 60bh. Positioned and formed with reference to 60b.

The configuration of the present invention can be applied to any layer of the inner layer, the outermost layer, and the core layer. In the above-described embodiment, the core substrate and the interlayer insulating layer use the prepreg provided with the core material, but it is also possible to use a resin layer that does not include the core material.

10 printed wiring board 30 core substrate 34a reference land 34b positioning land 34d via land 50 interlayer insulating layer 51b positioning opening 51d via opening 60 filled via 60b dummy via 60bh positioning recess

Claims (13)

Providing a substrate having a conductor layer;
Forming an interlayer insulating layer on the substrate;
Forming a via opening extending through the interlayer insulating layer to the conductor layer with a laser and a positioning opening having a larger diameter than the via opening;
Forming a conductor having a recess in the positioning opening by plating;
Forming a resist film having a predetermined pattern on the formed plating with reference to the position of the concave portion. A method of manufacturing a printed wiring board according to claim 1, wherein:
A filled via is formed in the via opening by the plating. A method of manufacturing a printed wiring board according to claim 1 or claim 2, wherein:
The diameter of the positioning opening is 1.5 times or more the diameter of the via opening. A method for producing a printed wiring board according to any one of claims 1 to 3, comprising:
A dummy via conductor having a recess is formed in the positioning opening. A method for producing a printed wiring board according to any one of claims 1 to 4, wherein:
The recess is formed to a depth of 30 to 150 μm. A method for producing a printed wiring board according to any one of claims 1 to 5, comprising:
The interlayer insulating layer is made of a prepreg formed by impregnating a core material with a resin. A method for manufacturing a printed wiring board according to any one of claims 1 to 6, comprising:
Forming a metal foil on the interlayer insulating layer, wherein the plating is formed in the via opening and in the positioning opening on the metal foil. A method of manufacturing a printed wiring board according to claim 7, wherein:
Including reducing the thickness of the metal foil before laser irradiation. A method of manufacturing a printed wiring board according to any one of claims 1 to 8, comprising:
The plurality of positioning openings are arranged in a predetermined pattern. A method for producing a printed wiring board according to any one of claims 1 to 9, comprising:
The resist film is formed in the predetermined pattern by forming a photosensitive resist film on the plating, exposing and developing the concave portion under the photosensitive resist film as a reference, and developing. It is a manufacturing method of the printed wiring board of any one of Claims 1-10, Comprising:
The laser-use via opening and positioning opening are formed in advance on the substrate by using a positioning mark as a reference. A method of manufacturing a printed wiring board according to any one of claims 1 to 11, comprising:
A circuit pattern is formed by removing the plating on the non-formed portion of the resist film. A method for producing a printed wiring board according to any one of claims 1 to 12, wherein:
The via openings and positioning openings by the laser are formed by irradiating laser light in a spot shape.

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