JP3328630B2 - Printed wiring board and method of manufacturing printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board and a printed wiring board in which a resist pattern is formed on an interlayer resin insulating layer, and a conductive circuit is provided by depositing plating on a portion where the resist pattern is not formed. The present invention relates to a method for manufacturing a plate.

[0002]

2. Description of the Related Art In a method of manufacturing a so-called build-up multilayer printed wiring board, an uncured interlayer resin insulating material (adhesive for electroless plating) is applied by a roll coater, dried and cured, and then a via hole is formed. Formed and plated to form conductor circuits.

[0003] A manufacturing process of this build-up multilayer printed wiring board will be described with reference to FIG. An interlayer resin insulation layer 180 is applied to the substrate 120 on which the inner conductor circuit 124a and the positioning mark 124b are formed (FIG. 1).
8 (A)). Then, an opening 181 for forming a via hole is formed in the interlayer resin insulating layer 180 by etching (FIG. 18B). After that, an electroless plating film 182 is uniformly formed by electroless plating (FIG. 18C).

After placing the dry film 183, the photomask 1 on which the predetermined pattern 184a is formed is formed.
At 84, the dry film 183 is exposed (FIG. 18).
(D)). The exposed portion of the dry film 183 is removed with a solvent to form a resist 185.
(E)). Then, the plating film 186 is formed on the resist non-formed portion.
Is formed (FIG. 18F). After that, resist 18
5 and the electroless plating film 1 under the resist 185
By removing 82, a via hole 187 is formed.

Here, the photomask 184 is formed by a conductive circuit 124 a under the interlayer resin insulation layer (dry film) 180.
Must be placed in a position that exactly matches the Therefore, the positioning mark 124b is formed on the substrate 120 side, and the positioning mark 18b is formed on the photomask 184 side.
4b is formed, the positioning mark 184b is recognized by the image processing technique, and the two are aligned to align the photomask 184. That is, FIG.
As shown in (D), the substrate 12 is irradiated with light from below.
The transmitted light of the positioning mark 124b on the 0 side and the positioning mark 184b on the photomask 184 side is transmitted to the upper camera 2
At 00, the photomask film 184 is positioned by overlapping both.

However, in the above manufacturing method, the electroless plating film 182 is formed on the entire surface of the interlayer resin insulating layer 180,
Since the photosensitive dry film 183 is pressed on the metal film 182 which is the electroless plating film, the metal film 182 is in the way, and it is difficult to recognize the above-described positioning mark using the transmitted light. For this reason, before forming a metal film on the interlayer resin insulation layer, mask the relevant portions of the positioning marks for exposure of the dry film resist with a tape or the like, remove the metal film and the masking, and then remove the dry film. Positioning was performed by using a positioning mark with the glass mask and masking portion removed.

[0007]

However, the method of masking a positioning mark for forming a resist pattern is based on a method of masking the positioning mark when the masking position is displaced, or the masking portion is detached or peeled off during plating. A part may be covered with a metal film, making automatic recognition impossible. In addition, it has been found that when the masking is performed, foreign matter may adhere to the substrate at the time of attachment / detachment, and the occurrence rate of defective products increases.

Further, the positioning using the transmitted light is performed with respect to a positioning mark 124b provided below the interlayer resin insulating layer 180 as shown in FIG. That is, since the positioning is not performed with respect to the via hole opening 181 formed in the interlayer resin insulating layer 180, the positioning accuracy with respect to the opening 181 is low.

The applicant of the present invention has proposed a method of detecting a positioning mark using reflected light, as disclosed in Japanese Patent Application No. Hei 9-217076.
And Japanese Patent Application No. 11-017334. In the former, as shown in FIG. 19 (A1), exposure and development were performed using a positioning mark 346 provided with a concave portion of the interlayer resin insulating layer 340 on the conductor layer 334. The latter is shown in FIG.
As shown in 1), a positioning mark 346 made of a concave portion is provided in the interlayer resin insulating layer 340 on the conductor layer 334,
The reflectance of the positioning mark 346 has been increased by removing the conductor layer 334 thereunder.

[0010] However, in the former, since the positioning mark is formed by exposure and development, the exposed conductor layer 3 under the concave portion is formed.
The roughened layer 334α remains on the surface of the. Further, as shown in FIG.
a may remain. For this reason, FIG. 19 (A1), (A
FIG. 19A showing a sketch of the positioning mark of 2).
2) and (B2), the contrast difference in the positioning mark is small. Therefore, as shown in FIGS. 19 (A3) and (B3) showing sketches obtained by performing image processing on images of positioning marks photographed after forming a dry film on the upper part, the difference in contrast from other portions is small, and recognition of the positioning marks is performed. Was difficult.

In the latter, as shown in FIG. 20A1, since the lower conductive layer is removed, when a concave portion for a positioning mark is formed in the interlayer resin insulating layer 340 by laser, the lower resin layer 330 is removed. 20A shown in a plan view of the positioning mark.
a. Therefore, the metal film 3 is formed on the interlayer resin insulation layer.
When the dry film 350 is attached after forming the 48, as shown in FIG. 20 (A3), the metal film 348 and the dry film 350 enter into the depression 330a, and a diagram showing a sketch of image processing of the image of the positioning mark is shown. 2
As in the case of 0 (A4), the contrast difference from other portions was small, and it was difficult to recognize the positioning mark. Also, when image processing is performed due to factors such as the thickness and color tone of the dry film and the interlayer resin insulating layer, the type, thickness, and state of the metal film of the concave portion and the lower conductor layer, the positioning mark and other portions (dry film Or, the difference in contrast with the interlayer resin insulating layer) becomes very small, so that the alignment with the mask may not be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a printed circuit having excellent connection reliability, in which formation of a conductor circuit via a via hole between layers is not displaced. It is to propose a method for manufacturing a wiring board and a printed wiring board.

[0013]

In order to achieve the above object, according to the first aspect of the present invention, a metal layer having a roughened surface and an interlayer resin insulating layer constituting a conductive circuit are alternately laminated. A concave portion is formed in the interlayer resin insulating layer provided on the metal layer, and the metal layer from which the roughened surface has been peeled is exposed at a lower portion in the concave portion. It is a technical feature of the present invention to provide a positioning mark.

According to the second aspect of the present invention, a conductor circuit is formed.
A printed wiring board formed by alternately laminating a metal layer having a roughened surface and an interlayer resin insulating layer, wherein a recess is formed in the interlayer resin insulating layer provided on the metal layer. ,
At the bottom of the recess, and technical further comprising a positioning mark said metal layer having a removed shiny surface of the roughened surface is exposed.

According to a second aspect of the present invention, there is provided a printed wiring board in which metal layers and interlayer resin insulation layers constituting a conductive circuit are alternately laminated, wherein the interlayer resin insulation layer provided on the metal layer is provided. A technical feature is that a concave portion is formed in the layer, and a positioning mark formed by exposing a metal layer having a glossy surface is provided at a lower portion in the concave portion.

According to a second aspect of the present invention, a concave portion is formed in the interlayer resin insulating layer provided on the metal layer by a laser or the like, and a glossy surface is provided on the metal layer exposed from the lower portion of the concave portion to form a positioning mark. I have. As a result, the amount of light reflected from the positioning mark increases, so that even when a dry film is attached and image processing is performed by a reflection method, the difference in contrast between the positioning mark and other plating film portions increases,
Recognition of the positioning mark can be performed reliably and accurately.

The width of the recess is preferably 100 to 300 μm. The reason for this is that if the thickness is less than 100 μm, the width is too small to read easily, and if it exceeds 300 μm, the plating resist is attached.

According to the third aspect of the present invention, the exposed metal layer in the concave portion has a gloss within a range of 0.10 to 0.70. Particularly desirable is 0.3 to 0.6. Within this range, even if a metal film is formed in the concave portion of the interlayer resin insulating layer and the positioning mark, the contrast of the exposed metal layer (glossy surface) of the positioning mark becomes clear. Therefore, even after attaching the dry film, the image can be accurately recognized by the reflection type image processing.

For the measurement of glossiness, GAMMODE manufactured by Graphic Arts Manufacturing Company (GAMMODE) was used.
L 144 DENSITOMETER) was used. First, the origin of glossiness is measured. Measure the original white sample and black sample alternately for measuring the origin,
Correct the value of the glossiness described for each device (white is 0, black is 2.0, and the glossiness is the degree of color in between). After the correction, the metal layer corresponding to the formed positioning mark is measured, and the value measured three or more times is the gloss.

When the glossiness is 0.10 to 0.70, the positioning mark can be recognized. The gloss is 0.
If it exceeds 70, the difference in contrast between the positioning mark and the dry film becomes small. for that reason,
When the image recognition is performed by the reflection type, it is difficult to distinguish between the positioning mark and the dry film, so that the mask cannot be aligned or the mask is displaced. When the glossiness is less than 0.10, the contrast between the positioning mark and the dry film is too strong, so that the contour of the positioning mark is blurred and accurate positioning cannot be performed.

It is desirable that the difference in contrast between the positioning mark of the concave portion and the interlayer resin insulating layer is 0.30 to 0.70. If the difference is smaller than 0.30, it becomes difficult to recognize the positioning mark and the dry film or the positioning mark and the positioning mark of the mask,
The misalignment increases, and it becomes difficult to perform mechanical correction. If it exceeds 0.70, the outline of the positioning mark is blurred, and the positioning mark cannot be accurately formed.

According to a fifth aspect of the present invention, the interlayer resin insulating layer is formed by pressing a resin film. Because it is a film, it is easy to handle when forming the interlayer resin insulation layer,
Resin can withstand the formation of marks.

According to a sixth aspect of the present invention, there is provided a method for manufacturing a printed wiring board.
Technical features include at least the following steps (a) to (h): (a) a step of forming a roughened surface on a metal layer serving as a conductor circuit on a substrate; (b) a step of forming a roughened surface on the metal layer (C) forming a via hole in the interlayer resin insulating layer by laser or exposure and development processing; and (d) simultaneously or before and after the step (c) with a laser. Forming a positioning mark composed of a concave portion exposing the metal layer from which the roughened surface has been removed in the interlayer resin insulating layer; (e) a metal film on the surface of the interlayer resin insulating layer, the via hole and the concave portion (F) pressing a photosensitive dry film on the substrate; (g) aligning a mask with a positioning mark of the substrate by reflection-type image processing, and performing exposure and development processing. Through Forming a plating resist pattern for forming a conductor circuit; (h) forming a conductor circuit by electrolytic plating;
Removing the plating resist and dissolving and removing the metal film existing under the plating resist;

According to a sixth aspect of the present invention, a recess is formed in the interlayer resin insulating layer provided on the metal layer on which the roughened surface is formed by a laser, and the roughening of the metal layer exposed from the lower portion of the recess is performed. The positioning mark is formed by removing the surface with a laser. Thereafter, a photosensitive dry film is pressure-bonded to the substrate, and positioning is performed on the positioning mark by reflection-type image processing. Since the roughened surface of the metal layer is removed and the amount of light reflected from the positioning mark is increased, the image of the positioning mark can be accurately recognized by the reflection type image processing. Therefore, it is possible to manufacture a printed wiring board which is excellent in connection reliability and has no positional deviation in the formation of a conductor circuit via a via hole between layers. The position of the metal film coated on the concave portion can be adjusted even if the metal film is formed by electroless plating, sputtering, evaporation or the like.

According to a seventh aspect of the present invention, there is provided a method for manufacturing a printed wiring board.
Technical features include at least the following steps (a) to (g): (a) a step of forming an interlayer resin insulation layer on a metal layer to be a conductor circuit; (b) the interlayer resin insulation layer Forming a via hole by laser or exposure / development processing; and (c) simultaneously or before and after the step (b), by using a laser to expose the metal layer having a glossy surface to the interlayer resin insulation layer from the concave portion. (D) forming a metal film on the surface of the interlayer resin insulating layer, the via hole and the concave portion; (e) pressing a photosensitive dry film on the substrate; (F) Positioning of the mask with respect to the positioning mark of the substrate by reflection type image processing, and through exposure and development processing, a plating resist pattern for forming a conductive circuit is formed. A step of forming, by (g) electroplating, to form a conductor circuit, and then,
Removing the plating resist and dissolving and removing the metal film existing under the plating resist;

According to a seventh aspect of the present invention, a concave portion is formed in the interlayer resin insulating layer provided on the metal layer by laser, and a glossy surface is provided on the metal layer exposed from the lower portion of the concave portion, and the positioning mark is formed. Has formed. Thereafter, a photosensitive dry film is pressure-bonded to the substrate, and positioning is performed on the positioning mark by reflection-type image processing. Since the metal layer is provided with a glossy surface by the laser to increase the amount of light reflected from the positioning mark, the image of the positioning mark can be accurately recognized by reflection-type image processing. Therefore, it is possible to manufacture a printed wiring board which is excellent in connection reliability and has no positional deviation in the formation of a conductor circuit via a via hole between layers. The position of the metal film coated on the concave portion can be adjusted even if the metal film is formed by electroless plating, sputtering, evaporation or the like.

According to the eighth aspect of the present invention, the interlayer resin insulation layer is
It is formed by pressing a resin film. Since it is a film, it is easy to handle when forming the interlayer resin insulating layer.

In the ninth aspect, after forming a concave portion in the interlayer resin insulating layer by laser, an annealing process or an oxide film removing process is performed. This is because the plating film has non-uniform gloss, and the plating of the ring-shaped concave part of the positioning mark may not be able to recognize an image after the compression of the dry film due to non-uniform gloss. Therefore, in order to make the gloss of the plating film uniform and to improve the adhesion between the plating film and the interlayer resin insulating layer, after forming the plating film, annealing treatment,
It is preferable to perform an acid treatment or an oxide film removing treatment for etching about 0.1 μm. As a condition of the annealing treatment, it is preferable to heat at a temperature of 50 to 250 ° C. for 10 minutes or more. Depending on factors such as the composition of the plating solution, the thickness of the plating film, and the roughness of the interlayer insulating layer, the annealing temperature may be increased gradually from a low temperature. As the oxide film removal treatment, a 10 wt% sulfuric acid solution or 0.1 μm
There is a method of light etching to a degree. By performing the oxide film removal treatment after the annealing treatment, the uniformity of the gloss of the plating film can be improved, so that the image recognition can be performed with high accuracy.

According to the tenth aspect, when forming the positioning mark, at least one or more selected from laser processing of carbonic acid, excimer, YAG, and UV is used. In particular, it is preferable to use a carbon dioxide laser. This makes it possible to remove the roughened surface of the exposed metal layer, and it is possible to provide a glossy surface on the exposed metal layer regardless of the type and state of the metal layer.

When forming with a carbon dioxide gas laser,
The following conditions are preferred. Pulse energy 0.1 to 200 mJ, pulse width 1 to 100 μs, pulse interval 0.5 ms or more Number of shots 1 to 1000 shots At this time, if the magnitude of the pulse energy is less than 0.1 mJ, a glossy surface is formed on the exposed metal layer. Cannot be applied. On the other hand, if it exceeds 200 mJ, there may be a case where a defect occurs in the formed mark itself due to unevenness in the resin layer portion of the formed positioning mark. The same can be said for the pulse width.

In the case of forming with an excimer laser,
The following conditions are preferred. Frequency: 50 to 200 Hz Energy: 0.1 to 5.0 J Number of shots: 50 to 200 Shots A mask having at least an opening where a positioning mark is to be formed is placed on the interlayer resin insulating layer, and the portion is irradiated with excimer laser. Then, the positioning marks are formed by opening the interlayer resin insulating layer.

The processing method of the image picked up by the reflection method can be performed by a method called "binary processing" by digital processing or "gray processing" by analog processing. What is called "binarization processing" is to recognize in image processing by binarizing (white / black) the difference in contrast between a mark to be positioned and a part other than the mark,
This is for positioning the substrate and the mask. Specifically, the positioning mark is irradiated with light from above and imaged by a camera for image recognition, and the positioning mark (ring-shaped concave portion) having a large amount of reflection is reflected by white and other reflection marks covered with a dry film. By determining that the plating portion having a small amount (other than the ring-shaped concave portion) is black, the positioning mark (white) is recognized, and the substrate and the mask are aligned.

On the other hand, what is called “gray processing”
By determining the difference in contrast between the mark to be positioned and a portion other than the mark as a difference in the rate of change in brightness (displacement point), it is recognized by image processing to perform positioning between the substrate and the mask. . Specifically, the positioning mark is imaged from above by a camera for image recognition, and the difference in brightness between the positioning mark (for the ring-shaped concave portion) and the plating portion covered with the other dry film is compared with the contrast difference. , The positioning mark is recognized, and the position of the substrate and the position of the mask are aligned.

For the reflection type image processing, either of the binarization processing and the gray processing may be used, and the selection is made by selecting factors such as the shape, size, and depth of the ring-shaped concave portion to be formed, It depends on the factors at the time of image recognition, such as the color and thickness of the dry film used, the color, thickness, and roughness of the interlayer insulating layer. The binarization process has an advantage that image processing is easy and the processing time can be reduced. On the other hand, for a change in recognition such as a defect in the shape of the ring (chipping, elution of a dry film) and a case where the difference in contrast is relatively unclear, the gray processing determined by the change rate of brightness is more suitable. I have.

Next, a method of manufacturing a printed wiring board using the positioning marks of the present invention will be described. One layer is formed through at least the following roughened surface forming step to the conductive circuit forming step, but after the conductive circuit forming step, the upper layer is further formed by repeating the interlayer resin insulating layer forming step to the conductive circuit forming step. Can also.

Roughened Surface Forming Step-First, a substrate on which a circuit is formed in advance is prepared. As the substrate, a substrate in which a land and a conductive circuit are formed by forming through holes in a double-sided copper-clad laminate may be used. In addition to the copper-clad laminate, a ceramic substrate, an alumina substrate, or an aluminum nitride substrate may be used. Next, a roughened surface is formed on the metal layer (conductor circuit) of the substrate. As a method of forming a roughened surface, for example, oxidation (blackening)
A reduction treatment, an electroless plating film made of an alloy made of Cu-Ni-P, or an etching treatment made of an etching solution made of a cupric complex and an organic acid salt.

Interlayer resin insulation layer step—An interlayer resin insulation layer is formed on the substrate. The thickness of the interlayer resin insulation layer is 15 to 60
It is good to form in the range of μm. The interlayer insulating resin layer may be formed by press-fitting a coated or semi-cured resin film. The resin to be formed may be a thermosetting resin, a thermoplastic resin, or a composite thereof. As the resin, an epoxy resin, a polyimide resin, a phenol resin, a polyphenylene ether resin, a polyolefin resin, a fluororesin, or the like can be used. Among them, those which can be dissolved or dropped by an acid or an oxidizing agent to form a roughened surface may be used.

Via hole forming step-Via holes are formed in the interlayer resin insulating layer. The formation of the via hole is performed by exposure and development processing or laser.

Positioning mark forming step-A positioning mark is formed on the interlayer resin insulating layer. The positioning mark is formed by laser at the same time as the formation of the via hole or before and after the formation of the via hole. By forming the positioning mark with a laser, the roughened surface formed on the metal layer in the exposed concave portion can be removed, and a glossy surface can be formed on the metal layer. As a laser to be used, a carbon dioxide gas laser, an excimer laser, a YAG laser, a UV laser, or the like can be used. The gloss of the metal layer of the positioning mark formed by the laser measured by a gloss meter is preferably in the range of 0.10 to 0.70. Within this range, even if a metal film is formed in the concave portion of the interlayer insulating resin layer and the positioning mark, the contrast becomes clear by the glossy surface of the positioning mark portion,
Even after attaching the dry film, the image can be recognized by the image processing by the reflection type. In particular, the glossiness is desirably 0.3 to 0.6. The reason is that positioning can be accurately performed regardless of the thickness of the interlayer resin insulating layer.

Metal film forming step-A metal film is applied to the surface of the interlayer resin insulating layer, the via holes and the concave portions of the positioning marks.
Before forming the metal layer, a roughened layer may be provided on the surface of the interlayer resin insulating layer with an acid or an oxidizing agent. The metal film to be formed is formed by electroless plating, sputtering, vapor deposition, or the like. Further, a composite thereof may be used. It is preferable to form with copper, nickel, zinc, tin, iron, etc. in a thickness of 0.01 to 3 μm. Among them, copper is 0.1-2
It is good to form between μm. Within this range, a metal film can be uniformly formed on one surface regardless of the presence or absence of a roughened surface.

Dry film pressure bonding step-A photosensitive dry film is pressed on a metal film. The thickness of the dry film is preferably in the range of 15 to 35 μm.

Alignment step--Positioning of the substrate and the mask is performed by reflection-type image processing, and exposure is performed to form a plating resist pattern. The reflection-type image processing is performed by the above-described binarization processing or gray processing. The method of image processing and exposure is as follows [1]-
It is performed in the order of [7].

[1] A ring-shaped concave portion for positioning marks formed on a substrate on which a metal film is applied and a dry film is attached is illuminated from the front, and reflected light is imaged by a camera. At that time, an image may be taken by illuminating the ring-shaped concave portion with a ring-shaped illuminator fixed to the camera (first imaging coarse positioning). Imaging can be performed by sequentially performing a plurality of positioning marks with one camera, or simultaneously capturing each positioning mark with a plurality of cameras.

[2] An image of the positioning mark on the substrate is taken through the mask, and the taken image is displayed on a television monitor. [3] calculating the displacement distance and angle of the positioning mark, and transmitting the calculated distance and angle data to the substrate, the mask, or both the substrate holding side and the mask holding side;
The position is corrected mechanically. [4] Next, the positioning mark of the illuminated substrate and the black circle printed on the mask are simultaneously imaged by the camera (second imaging position adjustment). [5] Perform the same operation as in [2] and [3], and perform alignment between the substrate and the