JP2943767B2 - Method for manufacturing multilayer 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 method for manufacturing a multilayer wiring board, and more particularly to a method for manufacturing a ceramic multilayer wiring board by a grease sheet laminating method.

[0002]

2. Description of the Related Art Hitherto, a ceramic multilayer wiring board has been used as a high-density mounting circuit board because a high multilayer wiring can be easily formed by a green sheet laminating method. FIG. 3 is a schematic view illustrating an example of a method for manufacturing a ceramic multilayer wiring board. As a method of manufacturing the ceramic multilayer wiring board, a conductor paste is printed by a screen printing method or the like on the ceramic green sheet 8 on which the vias 10 are formed to form a wiring pattern 6, and then the ceramic green sheets 8 are overlapped with each other. A green sheet laminating method is known in which a laminated body is produced by press bonding and is fired to form a ceramic multilayer wiring substrate. The green sheet 8 is provided with guide holes 7, and it is general to perform alignment of circuit pattern printing and alignment of upper and lower layers during lamination based on the guide holes 7.

[0003] As a method of forming a fine circuit pattern,
A method using a photosensitive conductor paste is known. For example, Japanese Patent Application Laid-Open No. 5-287221 discloses a technique of printing a solid pattern of a photosensitive Cu paste and then exposing and developing ultraviolet rays using a mask to form a fine wiring pattern.

When a ceramic multilayer wiring board having a fine wiring pattern is manufactured by the green sheet laminating method, the connection of the wiring pattern between the layers depends on the printing precision and lamination precision of the upper and lower layers.

[0005] In a process of forming a circuit pattern by a screen printing method or a photosensitive conductive paste based on guide holes formed in a grease sheet in advance,
Lamination displacement occurs due to limitations in printing accuracy and alignment accuracy. Further, in the process of determining the stacking position by passing the guide holes through the guide pins, stacking displacement occurs due to deformation of the guide holes due to insufficient strength of the ceramic green sheet. When a stacking shift occurs, if the shift amount increases, the upper and lower layers cannot be connected. As the wiring pattern becomes finer, the allowable range of lamination deviation tends to become smaller, and the above-mentioned limit of lamination accuracy has made it difficult to manufacture a multilayer wiring board having a fine wiring pattern.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a ceramic multilayer wiring board having a fine wiring pattern and laminated with high precision.

[0007]

According to the present invention, there is provided a grease sheet having a guide hole at a predetermined position and a via at a desired position. (2) A photosensitive sheet is coated with a photosensitive conductive paste, exposed and developed through a mask, and a guide hole is formed on the photosensitive sheet at the same position as the green sheet, and a desired hole corresponding to the via of the green sheet is formed. The circuit is formed as a pattern. (3) The photosensitive sheet on which the circuit pattern is formed and the green sheet are overlapped via guide holes, respectively, and the circuit pattern is transferred to the green sheet. (4) A green lamination method characterized by including stacking a plurality of green sheets having a desired circuit pattern obtained by the above (1) to (3) through respective guide holes. The method for manufacturing a multilayer wiring board and (b) the method according to (a), wherein the photosensitive sheet is an epoxy-based material.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

In the method of manufacturing a multilayer wiring board according to the present invention, a photosensitive conductive paste is applied on a photosensitive sheet, and is exposed and developed using a mask to simultaneously form a wiring pattern and a guide hole. The feature is that the guide holes are used to align with the green sheet having the guide holes at the same position, and the wiring pattern is transferred.

As the photosensitive sheet, an existing photocurable film may be used. Alternatively, a liquid photosensitive resin may be applied on a base film such as PET and heat-treated to form a sheet, or a photosensitive green sheet may be used. However, it is desirable to use a material having a small deformation of the guide hole at the time of lamination in order to enhance lamination accuracy, and it is possible to harden by a heat treatment at a temperature at which the conductive paste does not sinter, and to obtain an epoxy-based material which has sufficient strength. Is preferred.

The photosensitive conductive paste is made of A as a conductive material.
A photosensitive paste containing u, Ag, Cu, Pd, W or the like is used. As a method of applying this to the photosensitive sheet, there are screen printing, spin coating, and the like, but it is desirable to use screen printing in which the control of the printing area and printing thickness is relatively easy.

In order to simultaneously form a wiring pattern and a guide hole by exposure and development, it is necessary to form both the guide hole and the wiring pattern on the same mask. Furthermore, heat treatment or the like is performed as necessary to secure the strength of the sheet after exposure and development and to prevent deformation of the guide holes during lamination.

Next, an overall configuration of an embodiment of the manufacturing method of the present invention will be described. FIG. 1 is a flowchart showing a method for manufacturing a multilayer wiring board according to the present invention. The photosensitive resin 1 exposes the wiring pattern forming portion 3 in advance. Next, the photosensitive conductive paste 4 is printed on the photosensitive resin 1. After the printed photosensitive conductor paste is sufficiently dried, exposure is performed through a mask 5 having a wiring pattern and guide holes, and a wiring pattern 6 and a guide hole 7 are simultaneously formed. After exposure and development, the photosensitive resin is heat-treated and cured to a sufficient degree to secure sufficient strength.
Next, the wiring pattern 6 is transferred to the green sheet 8 by superposition by aligning with the guide holes 7 and the guide pins 9. The green sheets thus obtained are similarly overlapped and laminated using guide holes and guide pins.

Since the guide hole and the wiring pattern are formed simultaneously using the same mask, the positional relationship does not change. In addition, by using a sheet with less deformation of the guide holes, a misalignment due to the alignment using the guide holes and the guide pins is small, and a multilayer wiring board stacked with high accuracy can be obtained.

[0015]

EXAMPLES Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto. FIG.
FIG. 2 is a flowchart showing one embodiment of the present invention. 200 mm x 200 mm size PE as base film 2
Using T, photosensitive resin 1 was applied thereto by spin coating. Polyimide was used as the photosensitive resin, and the thickness after drying was 40 μm. After drying at 80 ° C. for 30 minutes, 800 mJ /
subjected to exposure of cm ^2, and subjected to heat treatment again 80 ° C. 30 min. Then, the photosensitive conductive paste 4 was coated with the above-mentioned 100 mm
It was applied to an area of × 100 mm. The applied photosensitive conductor paste 4 was a photosensitive Ag paste, and the application was performed by screen printing using a solid pattern screen, and the thickness after drying was 20 μm. FIG. 4 is a schematic plan view showing the glass mask used in this example. Using the mask 5 in which the wiring pattern area 11 is arranged in the exposed portion and the guide hole area 12 is arranged in the periphery thereof, the photosensitive sheet is exposed to 800 mJ / cm ² to form the wiring pattern 6 and the guide hole 7. Formed at the same time. After development, 50 ° C
After drying for 1 hour and performing heat treatment at 160 ° C. for 1.5 hours,
It was inverted and the base film was peeled off. The glass ceramic green sheet 8 having a guide hole at the same position as the guide hole of the mask is overlapped with the above-mentioned photosensitive sheet via the guide pin 9 and a pressure of 1 atm is applied to transfer the wiring pattern 6 to the green sheet 8. did. In this way,
A plurality of the obtained transfer green sheets were laminated to obtain a laminate of a multilayer wiring board, which was fired at 900 ° C. to obtain a glass ceramic multilayer wiring board.

Observation of the lamination displacement of the wiring pattern on the cross section of the obtained glass ceramic multilayer wiring board confirmed that the lamination was performed with high precision.

[0017]

As is apparent from the above description, according to the present invention, it is possible to obtain a multilayer wiring board having a fine wiring pattern and laminated with high accuracy.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method for manufacturing a multilayer wiring board of the present invention.

FIG. 2 is a flowchart showing one embodiment of the present invention.

FIG. 3 is a flowchart showing a conventional method for manufacturing a multilayer wiring board.

FIG. 4 is a schematic plan view showing an example of a mask used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive resin 2 Base film 3 Exposed part 4 Photosensitive conductive paste 5 Mask 6 Wiring pattern 7 Guide hole 8 Green sheet 9 Guide pin 10 Via 11 Wiring pattern area 12 Guide hole area

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05K 3/46 H05K 3/10-3/26 H05K 3/38

Claims (2)

(57) [Claims] 1. A method of manufacturing a multilayer wiring board by a green sheet laminating method, comprising the following steps: (1) preparing a grease sheet having a guide hole at a predetermined position and a via at a desired position; I do. (2) A photosensitive conductive paste is applied to the photosensitive sheet, exposed and developed through a mask, and the photosensitive sheet is provided with a guide hole at the same position as the green sheet, and a desired hole corresponding to the via of the green sheet. Is formed. (3) The photosensitive sheet on which the circuit pattern is formed and the green sheet are overlapped via guide holes, respectively, and the circuit pattern is transferred to the green sheet. (4) A plurality of green sheets having a desired circuit pattern obtained by the above (1) to (3) are overlapped and laminated via respective guide holes. 2. The method according to claim 1, wherein the photosensitive sheet is an epoxy material.