JP4257624B2 - Method for forming external terminals of laminated electronic components - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming an external terminal of a multilayer electronic component with an internal circuit built therein.
[0002]
[Prior art]
Conventionally, multilayer electronic components formed by laminating a required number of ceramic green sheets on which conductive patterns for internal circuits are formed and integrally firing have been proposed in various configurations. In this laminated electronic component, generally, external terminals for connecting the internal circuit and the mounting circuit are formed on the side surface of the laminated body.
[0003]
An example of a method for forming this external terminal is disclosed in JP-A-5-327222. In this method, a via hole hole for internal conduction and a through hole for an external terminal are formed in a ceramic green sheet, and the paste is dried after filling the through hole simultaneously with the via hole. From filling to drying, in order to prevent the conductive paste from falling from the through hole, a smooth plate is placed under the green sheet as a base. Thereafter, the internal circuit pattern is printed, and the conductor paste is dried and laminated. And it is the method of forming an external terminal by baking and cut | disconnecting.
[0004]
Japanese Patent Application Laid-Open No. 6-112999 prepares a mother board that has been baked and has a through hole formed at a position where an external electrode is to be formed. A method is disclosed in which external electrodes are applied so as to reach the thickness of each element and the individual elements are cut. This method is a method in which an external terminal is formed and then cut after firing the laminated electronic component.
[0005]
[Problems to be solved by the invention]
In the method disclosed in Japanese Patent Laid-Open No. 5-327222, poor conduction between the internal circuit and the external terminal occurs due to misalignment or deformation due to pressure when the green sheet is crimped, or due to deformation of the external terminal. There was a risk of defective external terminals.
Further, the method disclosed in Japanese Patent Application Laid-Open No. 6-1112099 requires a step of making a hole in the hard laminate after firing, which has a problem of high cost. In addition, it is conceivable to make a hole in the green sheet to make a laminate, and then apply the conductive paste. However, the through hole may be deformed due to misalignment or deformation at the time of pressure bonding, and the conductive paste may be removed. There was a problem that a problem that the coating could not be applied to the entire inner surface occurred.
[0006]
This multilayer electronic component is required to be reduced in size, price, and functionality, and is constantly being improved. Various methods for forming the external terminal have been proposed, but an object of the present invention is to provide a method for forming the external terminal which is easy to manufacture and can be co-fired with the laminated body and is inexpensive.
[0007]
[Means for Solving the Problems]
The present invention provides a method for forming an external terminal formed on a side surface of a laminated electronic component obtained by laminating and firing a ceramic green sheet on which a conductive pattern for an internal circuit is printed, and is divided after the ceramic green sheet. A hole for forming an external terminal is formed on the dividing line, and a predetermined ceramic green sheet in which an internal circuit pattern or a via hole for connecting an internal circuit is formed is laminated. A method for forming an external terminal of a laminated electronic component, comprising: forming a conductive material in the external terminal forming hole, performing a subsequent press-bonding, and firing the conductive material.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, holes for external terminals are formed in advance on a dividing line that is divided after each ceramic green sheet. Then, this ceramic green sheet in which an internal circuit pattern or a via hole for connecting the internal circuit pattern or the like is formed is laminated and temporarily pressed. A conductive material for an external terminal is formed in the state of this temporary press-bonded body. In other words, when the main pressure bonding is performed, there is a high risk of deformation due to the pressure being too strong, but by temporarily pressing with a force weaker than that, a laminate can be obtained with the deformation suppressed, and in this state A conductive material for external terminals is formed. This external terminal is divided and exposed to the side surface, and functions as an external terminal.
[0009]
This temporary pressure bonding is preferably performed under conditions of 20 ° C. to 60 ° C. and 10 to 200 kg / cm ² . More preferably, it is 40-120 kg / cm < ² >. Further, it is preferable that the temporary pressure bonding is performed with a weaker force than the main pressure bonding. Moreover, the state of this temporary press-bonded body is a state in which each layer is in close contact with each other, does not cause misalignment in handling after temporary press-bonding, and the stacked green sheets are not greatly deformed. That is, there is no extreme unevenness on the inner surface of the external terminal forming hole, or the external terminal hole is not crushed.
[0010]
In addition, the method for forming the conductive material for the external terminal is preferably a method in which the conductive paste is filled in the through holes by a printing method such as metal mask printing, and then sintered at a temperature of about 900 ° C. after being subjected to main pressure bonding. At this time, it is preferable that the conductive material is filled on the surface of the through hole with no gap and with a uniform thickness.
[0011]
An embodiment according to the present invention will be described with reference to the drawings. First, a ceramic green sheet is formed. The ceramic green sheet can be formed with a doctor blade or the like by forming a slurry of a required ceramic material. Holes 2 for forming external terminals are formed in the ceramic green sheet 1. This is shown in FIG. The external terminal forming hole 2 is formed on a dividing line 6 to be divided later. Of course, it forms in the required location of an external terminal. Further, when forming the external terminal forming hole 2, a via hole (not shown) for connecting an internal circuit may be appropriately formed. Next, a conductive pattern for an internal circuit is formed on a required ceramic green sheet. This can be formed by screen printing a conductive paste mainly composed of Ag. Then, a predetermined number of predetermined ceramic green sheets are stacked. At this time, necessary portions of the internal circuit are connected by via holes.
[0012]
The laminated body is temporarily pressure-bonded to obtain a temporary pressure-bonded body 3. This is shown in FIG. The temporary press-bonded body 3 is formed so that the holes 2 for forming the external terminals are stacked and penetrated from the upper surface to the lower surface. This temporary press-bonding was performed at a temperature of 25 ° C. and a pressure of 100 kg / cm ² for 60 seconds. The temperature for this temporary pressure bonding is preferably 20 to 60 ° C. The reason is that if the temperature is lower than 20 ° C., the pressure-bonding is not reliably performed and the stacked green sheets are displaced. Further, when the temperature exceeds 60 ° C., the pressure bonding becomes excessive, and the inner surface of the external terminal forming hole of the temporary pressure bonded body is deformed.
[0013]
The pressure for this temporary pressure bonding is preferably 10 to 200 kg / cm ² . The reason is that if it is less than 10 kg / cm ^2, it is not surely pressed and the stacked green sheets are displaced. Preferably it is 40-120 kg / cm < ² > or more. On the other hand, if it exceeds 200 kg / cm ² , the pressure bonding becomes excessive, and the inner surface of the external terminal forming hole of the temporary pressure bonded body is deformed.
[0014]
In the state of the temporary press-bonded body 3, an external terminal was formed by applying a conductive paste to the inner surface of the external terminal forming hole using a metal mask printing method. The printing metal mask and the pre-printed pre-bonded body are fixed at predetermined positions. The metal mask has a hole of the same diameter at the same position as the electrode forming hole of the temporary press-bonded body, and the conductive paste is supplied to the temporary press-bonded body by the movement of the printing squeegee. As the conductive paste, a commercially available silver paste (viscosity of about 30 Pa · S when measured at a rotation speed of 100 rpm and a temperature of 25 ° C.) was used and printed and applied while sucking the temporary press-bonded body. In the temporary press-bonded body, since the inner surface of the external terminal forming hole is not deformed by pressurization, the conductive paste easily moves on the inner surface of the hole. Therefore, the conductive paste does not stop at the upper part of the hole, and the conductive paste can be uniformly applied to the entire inner surface of the hole. Moreover, since it can be applied to the entire surface, the adhesion between the hole inner surface and the electrode material is good, and the reliability as an electrode is also excellent. FIG. 4 shows a cross-sectional view of the electrode material applied. The electrode material 4 of the external terminal is applied to the inner surface of the hole penetrating from the upper surface to the lower surface of the temporary pressure bonding body 3.
[0015]
Next, the temporary press-bonding body 3 is finally press-bonded. This main press-bonding was performed by setting the temporary press-bonded body on a pressurizing jig and pressurizing at a temperature of 85 ° C. and a pressure of about 110 kg / cm ² for 1 minute. The main press bonding is performed under conditions stronger than the temporary press bonding. And as conditions of this crimping | compression-bonding, it is preferable to carry out by the pressure of 10-400 kg / cm < ² >, and the temperature of 30-100 degreeC.
[0016]
And the desired pressurized electronic component was obtained by cut | disconnecting this this crimped body with a parting line, and baking at 900 degreeC for 2 hours. A perspective view of the laminated electronic component is shown in FIG. The external terminal 5 may be subjected to nickel plating, solder plating, or the like. Further, the dividing means may be a method in which a cut groove is formed and divided. Of course, it may be divided after firing.
[0017]
According to this embodiment, since the conductive material is formed in the external terminal forming hole after the temporary pressure bonding, deformation of the hole as seen after the final pressure bonding can be suppressed, and the adhesion between the inner surface of the external terminal forming hole and the conductive material is improved. Good and reliable electrode.
In addition, since the electrode is formed by a printing method to form the conductive material in the external terminal forming hole, the manufacturing is easy. Moreover, it is not necessary to control the suction at the time of electrode printing with high precision, and it can be manufactured inexpensively or easily.
[0018]
INDUSTRIAL APPLICABILITY The present invention is effective for an electronic component incorporating a single element, a composite component incorporating a plurality of elements, a composite component in which an electronic component is mounted on a laminate, or a multilayer substrate.
[0019]
【The invention's effect】
According to the present invention, the external terminal is formed in the process of forming the conductive material after the laminated body is temporarily pressure-bonded and then performing the pressure-bonding. Terminals can be formed.
[Brief description of the drawings]
FIG. 1 is a perspective view of an embodiment according to the present invention.
FIG. 2 is a plan view of a ceramic green sheet according to an embodiment of the present invention.
FIG. 3 is a perspective view of a temporary press-bonded body according to an embodiment of the present invention.
FIG. 4 is a cross-sectional view of an external terminal portion of one embodiment according to the present invention.
[Explanation of symbols]
1 Ceramic Green Sheet 2 External Terminal Hole 3 Temporary Pressure Bonding Body 4 External Terminal Electrode Material 5 External Terminal 6 Dividing Line

Claims (3)

In the method of forming external terminals formed on the side surface of the laminated electronic component obtained by appropriately laminating ceramic green sheets on which conductive patterns for internal circuits are printed and firing,
A hole for forming an external terminal is formed on a dividing line divided after the ceramic green sheet, and after laminating a predetermined ceramic green sheet, each layer of the ceramic green sheet is in close contact with each other. It is characterized in that it is temporarily crimped to such an extent that it does not collapse , a conductive material is formed in the continuous hole for forming the external terminal of the temporary crimped body, and then the final crimping is performed with a stronger force than the temporary crimping and fired. A method for forming an external terminal of a laminated electronic component. The method for forming an external terminal of a laminated electronic component according to claim 1, wherein the conditions of the temporary pressure bonding are a pressure of 10 to 200 kg / cm ² and a temperature of 20 to 60 ° C.   3. The method of forming an external terminal of a multilayer electronic component according to claim 1, wherein a conductive material is formed in the external terminal forming hole by applying a conductive paste by a metal mask printing method.

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