JPH06329479A - Multilayer substrate baked at low temperature - Google Patents

Abstract

PURPOSE:To obtain a multilayer substrate baked at low temperature by providing plural viewer holes in a part for printing a conductor so as to improve adhesion strength of the conductor. CONSTITUTION:Powders of glass and alumina, etc., used as main materials are kneaded with a binder, plasticizer and solvent, etc., in a prescribed ratio to form a green sheet and viewer holes 2 for connection are formed so as to conduct the upper and lower parts of this green sheet and a paste-like conductor 3 is packed into this viewer hole 2 and each wiring pattern 4 is printed based on specification of each layer by conductor printing, and then, green sheets each having these layers are laminated and thermally pressed to afford a laminated sheet and the laminated sheet is baked at <=1000 deg.C to prepare the objective multilayer substrate. Furthermore, in the laminated sheet, green sheets having plural viewer holes 5 with no mutual connection are provided to only several layers numbered from the surface and the prepared laminated sheet is baked at low temperature to form recessed parts consisting of the viewer holes 5, and Ag-based conductor 6 is printed on the surface of this multilayer substrate 1 baked at low temperature so as to penetrate the conductor into the recessed parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature fired multilayer substrate, and relates to a method for improving the adhesive strength of a conductor on the surface.

[0002]

2. Description of the Related Art A multilayer substrate such as ceramics is used as a wiring substrate for electronic equipment. In the production of this multilayer substrate such as ceramics, powder such as ceramics is used as a main material, and a binder, a plasticizer, a solvent, etc. The mixture is kneaded at a predetermined ratio, and a green sheet (sheet before sintering) is formed by a doctor blade method or the like. In order to connect the upper and lower sides of the green sheet, a via hole for connection is formed, and the via hole is filled with a paste-like conductor using a squeegee. When the filling of the paste-like conductor is completed, the wiring pattern is printed according to the specifications of each layer by conductor printing, and then the laminated green sheets for each layer are laminated on the lamination mold and thermocompression bonded by the lamination press. Then, a laminated sheet is obtained, and the laminated sheet is fired to produce a fired multilayer substrate. Alumina is often used as a main material in the ceramic multilayer substrate manufactured as described above, and the sintering temperature is about 1500 ° C. The baked multi-layer substrate further has A
A g-based conductor is printed and fired. In the case of alumina, the conductor adhesive strength is 3 Kg / 2 mm × 2 mm or more immediately after firing and after aging. However, glass + alumina or the like is used as a main material for a low temperature firing multi-layer substrate which is recently put into practical use and is performed at a temperature of 1000 ° C. or less, but the strength of the substrate itself is low, and a conductor printed on the substrate surface is also used. Also, there was a problem that the conductor adhesive strength of (1) was about 1/2 to 2/3 lower than the case where alumina was used as the main material. FIG. 2 is a conceptual diagram of an example of a conventional fired multilayer substrate. In the figure, 11 is a fired multilayer substrate, 2 is a via hole for connection, and the via hole 2 is filled with a paste-like conductor 3. The filled conductor is the wiring pattern 4 printed on the surface of the green sheet.
Is electrically connected to. 6 is a conductor formed by printing an Ag-based conductor on the surface of the fired multilayer substrate 11 and firing it.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the adhesive strength of a conductor formed by printing a conductor on the surface of a low temperature fired multilayer substrate, firing it, and aging it. An improved low temperature fired multilayer substrate is provided.

[0004]

In order to solve the above-mentioned problems, the present invention provides a low-temperature fired multilayer substrate produced by laminating green sheets, thermocompression-bonding them into a laminated sheet, and firing this laminated sheet at a low temperature. For several layers from the surface, a green sheet having a plurality of via holes with no connection is arranged, and the produced laminated sheet is baked at a low temperature to form a concave part formed of the via hole on the surface of the substrate. Conductor printing is performed on the surface of the low-temperature-fired multilayer substrate so that the conductor may enter into.

[0005]

With the above construction, the low temperature fired substrate according to the present invention has recesses formed at a plurality of positions on the surface on which the conductors are printed. In order to prevent peeling that occurs when it enters the interface between the low temperature fired multilayer substrate and the conductor, the conductor adhesive strength is significantly improved.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a conceptual diagram of an embodiment of a low temperature firing multilayer substrate according to the present invention. In the figure, reference numeral 1 is a low temperature fired multilayer substrate, but this low temperature fired substrate 1 is made of glass +
A powder such as alumina is used as a main material, a binder, a plasticizer, a solvent and the like are kneaded at a predetermined ratio, and a green sheet (sheet before sintering) is molded by a doctor blade method or the like,
A via hole 2 for connection is formed in order to electrically connect the top and bottom of the green sheet, and a paste-like conductor 3 is filled in the via hole 2 for connection using a squeegee. When the filling of the paste-like conductor 3 is completed, the wiring pattern 4 is printed by conductor printing based on the specifications for each layer, and then the green sheets for each layer on which the pattern 4 is printed are stacked on the lamination die to laminate the lamination pattern. It is thermocompression bonded by a press to obtain a laminated sheet, and this laminated sheet is heated to 1000 ° C.
It is produced by firing at the following temperature. In the above-mentioned laminated green sheets, a green sheet having a plurality of via holes 5 with no connection is provided for only a few layers from the surface to prepare a laminated sheet, and the laminated sheet is prepared as described above.
By low-temperature baking at a temperature of 00 ° C. or less, a concave portion formed of the via hole 5 is formed on the surface of the manufactured low-temperature baking multilayer substrate 1. Further, the low-temperature fired multilayer substrate 1 is printed with an Ag-based conductor 6 on the surface, and at this time, the conductor 6 is printed so as to enter the recess, and then fired.

[0007]

As described above, in the low temperature fired substrate according to the present invention, a plurality of concave portions are formed on the surface on which the conductor is printed, and the concave portions are formed by the conductor so as to anchor the substrate. In order to prevent peeling that occurs when it enters the interface between the low temperature fired multilayer substrate and the conductor, the conductor adhesive strength is significantly improved.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an example of a low temperature firing multilayer substrate of the present invention.

FIG. 2 is a conceptual diagram of an example of a conventional fired multilayer substrate.

[Explanation of symbols]

 1 Low-temperature fired multilayer substrate 2 Via hole for connection 3 Conductor 4 Wiring pattern 5 Via hole without connection 6 Conductor

Claims (2)

[Claims] 1. A low-temperature fired multilayer substrate produced by laminating green sheets and thermocompression-bonding them into a laminated sheet, and firing the laminated sheet at a low temperature, wherein several layers from the surface have a plurality of unconnected via holes. A low-temperature fired multilayer substrate, characterized in that a green sheet is provided and the produced laminated sheet is fired at a low temperature to form a concave portion formed of the via hole on the surface of the substrate. 2. A low temperature fired multi-layer substrate having a recess formed of a via hole on the surface of the substrate, wherein the conductor is printed on the surface of the low temperature fired multi-layer substrate so that the conductor is inserted into the recess. The low temperature fired multilayer substrate according to claim 1, which is characterized in that.