JPH0691336B2 - Electromagnetic shielding method for circuit boards - Google Patents

Description

The present invention relates to an electromagnetic circuit substrate, for example, an electromagnetic shield method for a hybrid IC or the like.

2. Description of the Related Art A conventional electromagnetic shield method is, for example, as shown in FIG. 6, an electric circuit board in which a predetermined circuit pattern 20 is arranged.
First, an insulating resin layer 30 having a predetermined film thickness is formed on 10 (hereinafter simply referred to as a substrate) by a method such as printing so that a part of the circuit pattern 20 is exposed.

Next, as shown in FIG. 7, the exposed circuit pattern 20
Is electrically connected to the insulating resin layer 30, and a conductive member layer 50 having a predetermined pattern and a predetermined thickness is formed by printing on the insulating resin layer 30.

The conductive member layer 50 contains a predetermined amount of conductive powder particles of silver, copper, carbon or the like in an insulating resin such as epoxy or acrylic, and has an electromagnetic shielding effect.

Further, as shown in FIG. 8, the insulating resin layer 60 is printed and formed in a predetermined pattern and a predetermined film thickness on the conductive member layer 50,
The electromagnetic shield process ends.

However, in the case of the above method, the conductive member layer 50 and the circuit pattern are formed.
In order to establish electrical connection with 20 and to be grounded (ground), a predetermined mask means is required when forming the pattern of the insulating resin layer 30 and the conductive member layer 50.

That is, three types of plate-making patterns are required for printing, and a predetermined mask means is required for spraying or brush coating.

The present invention has been made in view of the above problems and provides an electromagnetic shield method that facilitates the work of making a plate-making pattern, a mask means, or a mask work unnecessary.

Means for Solving the Problems In the electromagnetic shielding method of the present invention, a first pattern of insulation is formed on a first insulating layer laminated on a circuit pattern by using a laser processing means, and thereafter, insulation of the first layer is formed. By forming an electromagnetic shield layer (conductive member layer) on top of each other, an electrical connection between the electromagnetic shield layer and the circuit pattern can be established.

By the above-mentioned means, when forming the insulating layer and the electromagnetic shield layer, the plate making is unnecessary in the case of the printing means, and the predetermined mask means and the masking work are unnecessary in the case of the spraying and the brush coating.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a substrate 1 used for explaining the present invention, in which a circuit pattern 2 such as copper foil or Ag-Pd is arranged on one side or both sides of the substrate 1.

The embodiment of FIG. 1 shows an example in which the circuit pattern 2 is provided on one side for the sake of simplicity of explanation, and a double-sided wiring pattern such as a television circuit board or a hybrid IC board may be used.

When electromagnetically shielding the substrate 1 shown in FIG.
As shown in the figure, the first insulating resin layer 3 is formed by printing, spraying, brushing, or the like so as to have a predetermined thickness up to the end of the substrate, for example, 20 μm.

In this case, the printing means does not require a special plate-making pattern, and the spraying or brushing means does not require masking means or masking work.

Next, as a means for electrically connecting the electromagnetic shield material and the circuit pattern 2, a grounding hole 4 having a predetermined shape is formed in the first insulating resin layer 3 as shown in FIG.
Perforation is performed by using a laser processing means such as O ₂ or YAG.

After that, as shown in FIG. 4, a conductive member layer 5 for the purpose of electromagnetic shielding is formed to have a predetermined film thickness of, for example, 30 μm by printing or other means.

Further, as shown in FIG. 5, the second insulating resin layer 6 is printed on the conductive member layer 5 to a predetermined thickness and formed by another means, whereby the electromagnetic shield treatment of the substrate 1 is completed.

EFFECTS OF THE INVENTION According to the above-described configuration method, a special plate-making pattern, mask means, and work are unnecessary. Needless to say, this method is even more effective when an electric circuit component (not shown) is mounted on the circuit pattern.

[Brief description of drawings]

FIG. 1 is a sectional view of a circuit board used for explaining the method of the present invention,
2 to 5 are sectional views showing an electromagnetic shield forming process of the present invention, and FIGS. 6 to 8 are sectional views showing a conventional electromagnetic shield forming process. 1 ... Circuit board, 2 ... Circuit pattern, 3 ... First insulating layer, 4 ... Grounding hole, 5 ... Conductive member layer, 6 ... Second
Insulation layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-121699 (JP, A) JP-A-49-85557 (JP, A) JP-A-49-78171 (JP, A) Actual development Sho-57- 78672 (JP, U) Actual development Sho 58-37169 (JP, U)

Claims (1)

[Claims] 1. A first insulating layer is formed to have a predetermined film thickness by spray coating so as to cover a main surface of an electric circuit board, and a grounding hole is then laser-processed in this first insulating layer. Then, a conductive member layer for the purpose of electromagnetic shielding is overlaid on the first insulating layer to form a predetermined film thickness by means of spray coating, and then a second insulating layer is formed on the uppermost layer as a predetermined film. An electromagnetic shield method for a circuit board, characterized in that it is formed to a thick thickness by means of spray coating.