JP2001345556A - Method of manufacturing multilayered wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a multilayered wiring board which can improve the productivity. SOLUTION: A multilayered wiring board is manufactured, by the process of forming a plurality of projections 2 of trapezoid cross section on the top of a substrate 1, a process of forming a first wiring layer 3 whose one part is arranged on the projections 2 on the substrate 1 by the printing and baking of conductive paste, the process of forming an insulating layer 4 where a through-hole 6 is provided on the projection 2 on the substrate 1 by the printing and baking of glass paste, and the process of forming the second wiring layer 5, whose one part is arranged on the above projection 2 and which is electrically connected with the first wiring layer 3 within the through-hole 6 on the above insulating layer 4 by the printing and baking of the conductive paste.

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 in which a plurality of wiring layers are stacked with an insulating layer interposed therebetween.

[0002]

2. Description of the Related Art Hitherto, a multilayer wiring board has been used to constitute a semiconductor device or a recording head.

[0003] Such a conventional multilayer wiring board is, for example, shown in FIG.
As shown in FIG. 1, a first wiring layer 12 and a second wiring layer 13 made of a conductive material containing silver (Ag), gold (Au), or the like are provided on an upper surface of a substrate 11 made of glass, ceramic, or the like, and an insulating layer 14 is interposed therebetween. And the first wiring layer 12 and the second wiring layer 13 are electrically connected via a via hole 15 having a diameter of about 100 μm to 500 μm formed in the insulating layer 14. .

[0004] Such a conventional multilayer wiring board includes the following steps: (1) A conductive paste is printed on the upper surface of a substrate 11 in a predetermined pattern by a conventionally known screen printing, and the printed pattern is baked to deposit a first wiring layer 12 thereon. And (2) printing a glass paste on the substrate 11 on which the first wiring layer 12 is adhered in a predetermined pattern by screen printing and firing the glass paste to form a first pattern.
Forming an insulating layer 14 having a through hole at a predetermined position on the wiring layer 12; and (3) forming an insulating layer 14 in the through hole of the insulating layer 14;
A step of printing and filling the conductive paste by screen printing; and (4) a step of printing a conductive paste on the insulating layer 14 in a predetermined pattern by screen printing. Forming a connection conductor 16 in the through-hole and a second wiring layer 13 electrically connected to the connection conductor 16 on the through-hole by firing together with the conductive paste filled therein. Was.

[0005]

However, according to the above-mentioned conventional method for manufacturing a multilayer wiring board, the above (2)
Since the glass paste printed and fired on the substrate 11 in the step (1) has a predetermined fluidity until it is completely solidified, the design size of the through-hole is extremely large, for example, a diameter of 100 μm to 200 μm. If the size is small, the glass paste may flow into the through-hole and block the through-hole. In this case, the first wiring layer 12 and the second wiring layer 1
3 cannot be reliably connected by the connection conductor 16 or the like in the through-hole, and the production yield of the multilayer wiring board is reduced.

According to the above-described conventional method for manufacturing a multilayer wiring board, when the first wiring layer 11, the insulating layer 14, and the second wiring layer 13 are formed by screen printing, holes are formed corresponding to the patterns of the respective layers. It is necessary to position the screen plate with respect to the substrate 11 with high accuracy. Therefore, the pattern of each of the wiring layers 12 and 13 is extremely fine,
If the diameter of the through-hole is extremely small, it is difficult to accurately position each screen plate in a short time, and the productivity of the multilayer wiring board is reduced.

[0007]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and a method of manufacturing a multilayer wiring board according to the present invention comprises the steps of forming a plurality of trapezoidal projections on the upper surface of a substrate. A first part of which is arranged on the projection on the substrate
A step of forming a wiring layer by printing and baking a conductive paste; a step of forming an insulating layer having a through hole provided on the protrusion on the substrate by printing and baking a glass paste; Forming a second wiring layer partially disposed on the protrusion and electrically connected to the first wiring layer in the through hole by printing and firing a conductive paste. It is characterized by the following.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a multilayer wiring board manufactured by the manufacturing method of the present invention, wherein 1 is a substrate, 2 is a protrusion, 3 is a first wiring layer, 4 is an insulating layer, 5 is a second wiring layer, 6
Is a through hole, and 7 is a connection conductor.

The substrate 1 is made of an electrically insulating material such as alumina ceramics, mullite, aluminum nitride, glass ceramics, quartz, alkali glass, and alkali-free glass. 4. It functions as a supporting base material for supporting the second wiring layer 5.

On the upper surface of the substrate 1, a plurality of projections 2 are attached and formed at predetermined positions.

The projection 2 is formed such that its cross-section has a substantially trapezoidal shape in which the upper base is shorter than the lower base, and has a thickness of, for example, 5 μm when the thickness of an insulating layer 4 described later is 30 μm. １５15 μm.

On the substrate 1 having the protrusions 2,
The first wiring layer 3 and the second wiring layer 5 are provided in a predetermined pattern with the insulating layer 4 interposed therebetween.

The first wiring layer 3 and the second wiring layer 5 are made of a conductive material containing, for example, silver, gold, or an alloy thereof. And are electrically connected to each other via the via holes of the insulating layer 4 on the protrusions 2.

On the other hand, the insulating layer 4 interposed between the first wiring layer 3 and the second wiring layer 5 is formed of amorphous glass or the like to have a thickness of, for example, 15 μm to 100 μm. A through hole 6 is provided on the upper side, and a via hole is formed by filling the inside with a connection conductor 7.

In order to ensure good electrical insulation between the first wiring layer 3 and the second wiring layer 5 with this insulating layer 4, at least 15
A thickness of μm is required.

The via hole formed in the insulating layer 4 has a size corresponding to 1.5 to 8 times the line width of the wiring layers 3 and 5, for example, 50 μm, specifically, a diameter of 75 μm.
formed to have a columnar shape of about μm to 400 μm,
The first wiring layer 3 and the second wiring layer 5 function to electrically connect to each other at the intersection of the two.

The connecting conductor 7 forming the via hole
Is formed of the same conductive material as the first wiring layer 3 and the second wiring layer 5, for example, a conductive material including silver, gold, or an alloy thereof.

Next, a method for manufacturing the above-described multilayer wiring board will be described with reference to FIGS. (1) First, a substrate 1 is prepared, and a plurality of projections 2 having a trapezoidal cross section as shown in FIG.

When the substrate 1 is made of, for example, alumina ceramics, an appropriate organic solvent and a suitable solvent are added to and mixed with a ceramic raw material powder of alumina, silica, magnesia or the like to form a slurry. A ceramic green sheet (ceramic green sheet) is obtained by employing a blade method, a calender roll method, or the like, and thereafter, the green sheet is punched into a predetermined shape and fired at a high temperature (about 1600 ° C.). You.

The projections 2 are formed, for example, by applying a well-known screen printing on a top surface of the substrate 1 with a predetermined glass paste obtained by adding and mixing an appropriate organic solvent to, for example, lead-containing glass powder. By partially printing and firing it at a high temperature (500 ° C. to 800 ° C.)
It is formed to a thickness of from 15 μm to 15 μm. At this time, protrusion 2
It is important to control the viscosity and printing thickness of the glass paste within a predetermined range in order to make the cross-sectional shape of a substantially trapezoidal shape. For example, when using a glass paste mainly containing lead-containing glass, Is adjusted to, for example, 200 Pas, and the print thickness is set to, for example, 25 μm.

The height of these projections 2 is determined by the insulating layer 4 described later.
Is preferably set to a height of 30% to 60% with respect to the thickness. (2) Next, as shown in FIG. 2B, a first wiring layer 3 having a part disposed on the protrusion 2 is formed on the substrate 1.

The first wiring layer 3 is formed by adding a suitable organic solvent, an organic binder, a glass frit or the like to silver powder having a particle diameter of 1 μm or less and mixing the conductive paste with a conventionally known screen printing. A predetermined pattern is printed on the upper surface of the substrate 1 and is printed at a high temperature (350 ° C to 800 ° C).
Formed by baking.

At this time, the screen plate for forming the first wiring layer is positioned with respect to the substrate 1 so that a part of the perforated pattern is located on the projection 2.

At this time, in order to form the first wiring layer 3 as a good continuous film from the upper surface of the substrate 1 to the projection 2, the inclination angle of the slope of the projection 2 having a trapezoidal cross section should be adjusted. (3) Next, as shown in FIG. 2 (c), the insulating layer 4 having a plurality of through holes 6 on the substrate 1 is preferably formed. To form

The insulating layer 4 is formed by adding a suitable organic solvent to an amorphous glass powder and mixing the glass paste with a predetermined glass paste by well-known screen printing. Is formed by printing and applying over the entire upper surface of the substrate and baking it at a high temperature (400 ° C. to 500 ° C.).

At this time, the screen plate for forming the insulating layer is masked at the position where the through hole 6 is formed, and the screen plate is raised with respect to the substrate 1 by matching this portion with the position of the corresponding projection 2. Aligned to accuracy. Therefore, even when the diameter of the through-hole 6 is extremely small, the screen plate can be accurately positioned in a short time to improve the workability of the screen printing, and the productivity of the multilayer wiring board is improved. You.

In this case, since the projections 2 are formed at the positions where the through holes 6 are formed, the projections 2 prevent a part of the glass paste from flowing into the through holes 6 when the glass paste is printed. Until the glass is fired, the through holes 6
Can be left open.

In order to prevent the above-mentioned flow of the glass paste more reliably, it is preferable to set the inclination angle of the slope of the projection 2 to 20 degrees or more with respect to the upper surface of the substrate 1. (4) Next, as shown in FIG. 2D, the connection conductor 7 is filled in the through hole 6 of the insulating layer 4.

The connection conductor 7 is formed by adding a predetermined amount of metal fine particles having a particle size of 1 μm or less, an organic solvent, an organic binder, a glass frit, and the like in predetermined amounts and mixing the conductive paste. Is printed in the through-hole 6 so that a part thereof is in contact with the first wiring layer 3 in the through-hole 6, and is fired at a high temperature (400 ° C. to 600 ° C.) to fill the inside of the through-hole 6. Thereby, a via hole is formed in the insulating layer 4.

At this time, in the screen plate for forming the connection conductor, holes are formed in the portions where the connection conductors 7 are formed, and the screen plate is formed on the substrate 1 by aligning these pattern holes with the positions of the corresponding projections 2. Alignment with high accuracy. Therefore, even when the diameter of the through-hole 6 is extremely small, the screen plate can be accurately positioned in a short time to improve the workability of the screen printing, and the productivity of the multilayer wiring board is improved. You.

In this case, the projection 2 is provided inside the through hole 6.
Since the space filled with the conductive paste is narrow, the filling amount is relatively small, and the number of metal fine particles and the like contained in the conductive paste is also reduced. Accordingly, when the connection conductor 7 is formed, shrinkage of the conductive paste due to sintering of the metal fine particles contained in the conductive paste is suppressed to a small extent, and cracks are not effectively formed in the connection conductor 7. Can be.

The through-hole 6 is satisfactorily opened as described above, so that the conductive paste fills the inside of the through-hole 6 well. (5) Finally, a second wiring layer 5 is formed on the insulating layer 4 as shown in FIG.

The second wiring layer 5 is formed so that a part thereof passes over the connection conductor 7 provided on the projection 2 and is formed by the same method as the first wiring layer 3 described above. Is done. That is, a predetermined conductive paste obtained by adding and mixing an appropriate organic solvent, an organic binder, a glass frit, and the like to silver powder having a particle size of 1 μm or less is printed in a predetermined pattern on the upper surface of the insulating layer 4 by conventionally well-known screen printing. Then, by firing this at a high temperature (350 ° C. to 800 ° C.), the second wiring layer 5 is formed, thereby completing a multilayer wiring board as a product.

In this case, the first wiring layer 3 and the second wiring layer 5 can be reliably connected via the connection conductor 7 in the through hole 6, and the production yield of the multilayer wiring board is improved.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

For example, in the above embodiment, a multilayer wiring board in which two wiring layers are stacked has been described. However, the present invention is also applicable to a multilayer wiring board in which three or more wiring layers are stacked.

In the above-described embodiment, the firing of the wiring layers 3 and 5, the insulating layer 4 and the connection conductor 7 may be performed simultaneously or separately, and the firing may be performed simultaneously. Is also simplified.

Further, in the above-described embodiment, the first wiring layer 3 and the second wiring layer 5 are connected via the connection conductor 7 filled in the through-hole 6, but instead the second wiring layer 5 May be directly attached to the first wiring layer 3 in the through-hole 6 to electrically connect the two.

[0039]

According to the present invention, a projection is provided at a position where a through-hole is formed. Therefore, when a glass paste is printed on a substrate in forming an insulating layer, a part of the glass paste flows into the through-hole. The protrusion is blocked by a projection, and the through hole can be opened until the glass is fired. Therefore, the first wiring layer and the second wiring layer disposed above and below the insulating layer can be reliably connected via the connection conductor filled in the through hole, and the production yield of the multilayer wiring board is improved. You.

According to the present invention, the screen plate used for forming each layer constituting the multilayer wiring board can be aligned with the substrate by using a plurality of projections provided on the substrate. The screen plate can be accurately positioned in a short time to improve the workability of the screen printing, thereby improving the productivity of the multilayer wiring board.

[Brief description of the drawings]

FIG. 1 is a sectional view of a multilayer wiring board manufactured by a manufacturing method of the present invention.

FIGS. 2A to 2E are cross-sectional views for explaining steps of a method for manufacturing a multilayer wiring board according to one embodiment of the present invention.

FIG. 3 is a sectional view of a conventional multilayer wiring board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... protrusion, 3 ... 1st wiring layer, 4
... an insulating layer, 5 ... a second wiring layer, 6 ... a through hole,
7 Connection conductor

Claims (1)

[Claims] A step of forming a plurality of projections having a trapezoidal cross section on an upper surface of a substrate; and forming a first wiring layer partially disposed on the projections on the substrate by printing and firing a conductive paste. Forming an insulating layer having a through hole formed on the protrusion on the substrate by printing and baking a glass paste; and disposing a part of the insulating layer on the protrusion on the insulating layer. Forming a second wiring layer electrically connected to the first wiring layer in the through hole by printing and baking a conductive paste.