JPH0744328B2 - Electroplating method for electronic component substrates - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for electroplating a substrate for electronic parts, and also to electroplating a surface wiring pattern which is not connected to an external terminal to be a cathode electrode for electroplating. A suitable electroplating method that enables

[Conventional technology]

Conventionally, when attempting to perform electroplating on a surface wiring pattern which is not connected to an external terminal to be a cathode electrode for electroplating, as described in JP-A-59-153891, a pattern having a connection with the terminal. Alternatively, the terminals are connected by a conductive coating layer, and an insulating material is further coated on the terminals, and only the exposed pattern is subjected to desired electroplating. However, in this method, there is a possibility that a desired electroplating cannot be obtained due to a large connection resistance between the conductor coating layer and the pattern.

[Problems to be solved by the invention]

The above-mentioned prior art does not consider the relationship between the contact resistance between the conductor coating layer serving as the cathode electrode for electroplating and the wiring pattern under the coating layer and the throwing power of electroplating, and the contact resistance is large. If so, there is a problem that desired electroplating does not deposit.

An object of the present invention is to form a desired electroplating and film regardless of the magnitude of the contact resistance.

[Means for solving problems]

In order to achieve the above object, the present invention provides an external terminal (4) serving as a cathode for electroplating, a surface wiring pattern (2a) conducting to the external terminal (4), and the external terminal (4). A method for electroplating an electronic component substrate (1) having a plurality of surface wiring patterns (2b) not electrically conducting to a surface wiring pattern (2a) electrically conducting to the external terminal (4)
And a plurality of surface wiring patterns (2b) which are not electrically connected to the external terminals are connected by a peelable conductive paste (5), and at least the surface wiring patterns of the conductive paste (5) are commonly connected. The exposed portion (7) including the boundary portion with the surface wiring pattern is exposed and covered with the insulating material (6), and then electroplating is performed.

[Action]

When the external terminals are attached to the ceramic substrate for electronic parts and then electroplated, the external terminals can be used as a cathode electrode for electroplating and the surface wiring pattern connected to the external terminals can be electroplated. On the other hand, when performing electroplating on the surface pattern that is not connected to the external terminal, connect the pattern that is connected to the external terminal and the pattern that is not connected with the conductive coating layer,
Furthermore, there is a method of coating the insulating material on it and plating it to remove the conductive coating layer and the insulating material. In this method, if the connection resistance between the conductive coating layer and the surface wiring pattern is large, there is no connection with the external terminal. Electroplating does not deposit on the pattern. In the present invention, by exposing the conductive coating layer slightly from the insulating material, electroplating is deposited on that portion, and the plating film is connected to the surface wiring pattern, thereby connecting the conductive coating layer and the disconnection wiring pattern. A desired plating film can be formed even if the resistance is high.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.

FIG. 1 shows that after the metallized printing is performed, the lamination is performed and the external terminals 4 are connected to the external terminal mounting pads 3 of the ceramic substrate having the desired surface wiring patterns 2a and 2b, and the surface wiring patterns are electrically conductive. It has just been electrically connected by the coating layer (conductive paste) 5. here,
The surface wiring pattern 2a is a wiring pattern that is electrically connected to the external terminal 4 by an internal connection or the like, and the surface wiring pattern 2b is a wiring pattern that is not electrically connected (not electrically connected) to the external terminal 4. This surface wiring pattern is for connecting to another device, for example, a semiconductor chip carrier. The conductive coating layer is formed by dispersing and mixing silver powder in phenol resin, and is baked at 60 ° C. for 20 minutes.

FIG. 2 is a plan view showing a state in which the insulating material layer 6 is coated so as to expose the plated portion of the surface wiring pattern on the ceramic substrate and slightly expose the conductive coating layer (conductive coating layer exposed portion 7). FIG. The insulating material layer 6 may be selected from a plating resist that can be peeled off and removed simultaneously with the conductor coating layer.

FIG. 3 shows that after a desired plating layer 8 is formed on the surface wiring pattern by the electroplating method on the ceramic substrate shown in FIG. 2, the plating register and the conductive coating layer are made of, for example, chlorothene except for the conductive coating layer 7. FIG. 5 is a plan view and a cross-sectional view showing a state in which the plating film deposited on the surface of the conductive coating amount 7 is removed by honing, for example, sandblasting, after being washed and removed using an organic solvent. According to the present invention, it is possible to perform electroplating on a surface wiring pattern of a ceramic substrate that is not connected to an external terminal that is a cathode electrode for electroplating.

〔The invention's effect〕

According to the present invention, by slightly exposing the conductive coating layer to be the cathode electrode for electroplating, a desired plating film can be obtained even if the connection resistance between the conductive coating layer and the pattern to be plated is high, usually 20%. The plating non-precipitation defect that had appeared could be reduced to 0%.

[Brief description of drawings]

1 to 3 are views showing steps of one embodiment of the present invention. 1 ... Ceramic substrate, 2a ... Surface wiring pattern that is conductive with external terminals, 2b ... Surface wiring pattern that is not conductive with external terminals, 3 ... External terminal mounting pad, 4 ... External terminals, 5 ... ... conductive coating layer, 6 ... insulating material layer, 7 ... conductive coating layer exposed portion, 8 ... plating layer.

Claims (1)

[Claims] 1. An external terminal serving as a cathode electrode for electroplating,
In a method of electroplating a substrate for an electronic component, which has a surface wiring pattern conducting to the external terminal and a plurality of surface wiring patterns not conducting to the external terminal, a surface wiring pattern conducting to the external terminal And a plurality of surface wiring patterns that are not electrically connected to the external terminals are connected by a peelable conductive paste, and at least a portion of the conductive paste that connects the surface wiring patterns to each other is the surface wiring pattern. The method of electroplating is characterized in that it is exposed including the boundary portion thereof, is covered with an insulating material, and is then electroplated.