JPH06252534A - Printed wiring board with sealing and its manufacture - Google Patents

Abstract

PURPOSE:To provide a printed wiring board with improved adhesion property of a resin-sealing layer even if it is preserved under high-temperature and high- humidity environment and its manufacturing method. CONSTITUTION:The title printed wiring board is provided with a base circuit 1 consisting of copper formed on the surface of an insulation substrate 5, a header circuit 2 which is wider than the base circuit on the top surface of the base circuit 1, and a resin-sealing layer 4 for surrounding the base circuit 1 and the header circuit 2. After the header circuit 2 is formed on the copper foil surface where the insulation substrate 5 in that copper foil is provided on the surface is exposed, etching is performed on the copper foil surface where covered resist layer is eliminated, thus forming the base circuit 1 whose circuit width is narrower than that of the header circuit 2 and further the resin-sealing layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed printed wiring board used for electronic equipment and electric equipment, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional method for manufacturing a printed wiring board with a seal will be described with reference to the conventional printed wiring board with a seal shown in FIG. 3, and a base made of copper on the surface of an insulating substrate (5). After forming the circuit (1), the exposed surface of the base circuit (1) is plated with nickel (12) as a base plating, and further, the surface of the nickel (12) is plated with gold (13) to form the base circuit (1). After surrounding the
The periphery of 3) was sealed with a resin sealing layer (4) such as an epoxy resin in order to enhance the moisture resistance. However, in the conventional printed wiring board with encapsulation, when stored at high temperature and high humidity, the resin encapsulating layer (4) is weakly adhered and the resin encapsulating layer (4) is easily peeled off.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and an object of the present invention is to provide a resin-encapsulating layer having high adhesion even when stored at high temperature and high humidity. A printed wiring board and a method for manufacturing the same are provided.

[0004]

A printed wiring board with encapsulation according to the present invention comprises a base circuit (1) made of copper formed on the surface of an insulating substrate (5) and a top of the base circuit (1). A conductive path (3) consisting of a header circuit (2) made of nickel (2a) and / or gold (2b) wider than the circuit width of the base circuit (1) on the surface, and this conductive path (3)
And a resin sealing layer (4) surrounding the.

In the method for manufacturing a printed wiring board with a seal according to the present invention, the copper foil surface (16) located in the insulating path of the insulating substrate (5) having the copper foil (11) on the surface is the resist layer. Copper foil surface (18) covered with (17) and located in the conductive path
Copper foil surface (18) for conductive paths of resist-coated substrate
Is plated with nickel (2a) and / or gold (2b) to form the header circuit (2), the resist layer (17) is removed to expose the copper foil surface (16), and then the copper The foil surface (16) is etched to form a base circuit (1) having a narrower circuit width than the header circuit (2) to form a printed circuit board, and a resin sealing layer (4) is formed on the printed circuit board. It is characterized by doing.

[0006]

According to the encapsulation printed wiring board and the method for manufacturing the same according to the present invention, the header circuit (2) covers the copper foil surface (18) located in the conductive path, and the copper base circuit (1) is further etched by etching. ) Is formed. In this case, the side surface of the etched base circuit (1) is eluted, so that the base circuit (1) having a narrower circuit width than the header circuit (2) is
A constriction (10) is formed with reference to the header circuit (2). In the sealed printed wiring board of the present invention, since the resin sealing layer (4) is less likely to be constricted (10) in the base circuit (1), the adhesion is increased.

The present invention will be described in detail below. Figure 1
It is sectional drawing which expanded the principal part of the printed wiring board which concerns on the Example of this invention.

The printed wiring board with sealing of the present invention comprises a base circuit (1) made of copper formed on the surface of an insulating substrate (5), and a base circuit (1) on the top surface of the base circuit (1). Wider than the circuit width of nickel (2a), or /
And a header circuit (2) made of gold (2b) and a conductive path (3), and a resin sealing layer (4) surrounding the conductive path (3).

As the insulating substrate (5), an organic insulating plate obtained by curing a resin of a prepreg obtained by impregnating and drying a base material with a resin, or a ceramic insulating plate such as alumina is used. As the resin for the organic insulating plate, epoxy resin, polyimide resin, fluororesin, phenol resin, unsaturated polyester resin, PPO resin, etc. may be used alone.
Modified products, mixtures and the like are used. The base material of the organic insulating plate is not particularly limited, but an inorganic material such as glass fiber is preferable because it is excellent in heat resistance and moisture resistance. Further, an organic fiber cloth base material having excellent heat resistance and a mixture thereof can also be used.

The conductive path (3) is composed of a base circuit (1) and a header circuit (2), and the base circuit (1).
Is made of copper, and the header circuit (2) is nickel (2
a) or / and of gold (2b). When gold (2b) is used for the header circuit (2), it is formed on the surface of nickel (2) using nickel (2) as an underlying plating layer. As the resin forming the resin sealing layer (4), various known sealing materials such as epoxy resin are used and are not particularly limited.

Next, the manufacturing method of the present invention will be described in the case where gold (2b) is used for the header circuit (2). 2A to 2D are enlarged cross-sectional views of a main part showing a processing step.

As shown in FIG. 2A, for example, a copper foil (1
The insulating substrate (5) on which (1) is disposed is provided with a resist layer (1) such as a dry film photoresist or a liquid photoresist.
Cover with 7). A mask is overlaid on the surface of the coated resist layer (17) and exposed to light, and the portion to be an insulating path is photo-cured. Then, the uncured resist layer (17) is dissolved and removed by a developing solution, so that the copper foil surface (16) located in the insulating path of the insulating substrate (5) is changed to the resist layer (17).
Then, a resist-coated substrate is produced which is covered with and the copper foil surface (18) located in the conductive path (3) is exposed.

As shown in FIG. 2B, nickel (2a) is formed as an undercoat on the exposed copper foil surface (18) for a conductive path of the resist-coated substrate, and the nickel (2a) is formed.
Is plated with gold (2b). This nickel (2
The plating of a) and gold (2b) may be performed by a known plating method. Next, as shown in FIG. 2C, the resist layer (17) is removed by, for example, immersing it in a stripping solution in which the resist layer (17) is dissolved, and the copper foil surface (16) located in the insulating path.
Expose.

As shown in FIG. 3 (d), when the copper foil surface (16) located in the insulating path is removed by etching, a base circuit (1) made of copper covered with gold (2b) is formed. Together with this etching, the base circuit (1)
An arcuate constriction (10) is formed in the header circuit (2), and a printed circuit board having a base circuit (1) narrower than the circuit width of the header circuit (2) is formed. Thereafter, a resin sealing layer (4) is formed so as to surround a conductive path (3) composed of a base circuit (1) and a header circuit (2) of this printed circuit board, and a printed wiring board with a seal is manufactured. . The resin sealing layer (4) may be formed by a known sealing method and is not limited.

As described above, the header circuit (2) wider than the circuit width of the base circuit (1) is formed on the top surface of the base circuit (1), and the base circuit constricted with respect to the header circuit (2). Since (1) is surrounded by the resin encapsulating layer (4), the resin encapsulating layer (4) of the header circuit (2) is hard to fit into the constriction (10) of the base circuit (1), so that the adhesion is increased. .

[0016]

Example 1 A copper-clad glass-based epoxy resin laminate having a thickness of 0.6 mm was used as an insulating substrate (5). The surface of this laminated plate was covered with a dry film photoresist, a mask was overlaid and exposed to light, and the portion of the dry film photoresist to be an insulating path was photo-cured. The uncured dry film photoresist is dissolved in a developing solution and the copper foil surface (1
8) was exposed, and the exposed copper foil surface (18) was underplated with nickel (2a), and then gold (3b) was plated to form a header circuit (2). Then, the resist layer (17) was immersed in a stripping solution and removed to expose the copper foil surface (16) located in the insulating path. By etching the exposed copper foil surface (16), an arcuate constriction (1) is formed on the base circuit (1) with respect to the header circuit (2).
0) was formed, and the base circuit (1) narrower than the circuit width of the header circuit (2) was formed. Next, the conductive path (3) consisting of the base circuit (1) and the header circuit (2) was sealed with an epoxy resin to obtain a printed wiring board with a seal.

The adhesion of the resin sealing layer (4) of this printed wiring board with sealing was tested. The adhesion test is performed at a temperature of 12
PCT under conditions of 0 ° C and pressure of 2 kg / cm ² for 100 hours
After absorbing moisture with a tester, the base circuit (1) was observed with a magnifying glass, but the resin sealing layer (4) was not peeled off. or,
As a result of conducting an insulation test on 50 samples, there was no conduction failure.

Comparative Example 1 Using the same insulating substrate as in Example 1, a copper base circuit was formed on the surface by etching. This base circuit was plated with nickel and then with gold to form a header circuit.
After the base circuit and the header circuit were sealed with an epoxy resin as in Example 1, the adhesion of the resin sealing layer was tested under the same conditions as in Example. When the base circuit was observed, the resin sealing layer was peeled off. Further, as a result of the insulation test on 50 samples, 10 conduction defects were found.

[0019]

[Table 1]

[0020]

According to the manufacturing method of the present invention, the header circuit (2) wider than the circuit width of the base circuit (1) can be formed on the top surface of the base circuit (1).

The encapsulating printed wiring board of the present invention has good adhesiveness to the resin encapsulating layer (4) even when stored at high temperature and high humidity.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of a printed wiring board with sealing according to an embodiment of the present invention.

2A to 2D are enlarged cross-sectional views of a main part showing a processing step according to the manufacturing method of the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part of a sealed printed wiring board according to a conventional example.

[Explanation of symbols]

 1 Base Circuit 2 Header Circuit 2a Nickel 2b Gold 3 Conductive Path 4 Resin Sealing Layer 5 Insulating Substrate 10 Constriction 11 Copper Foil 16 Copper Foil Surface 17 Resist Layer 18 Copper Foil Surface

Claims (2)

[Claims] 1. A base circuit (1) made of copper formed on the surface of an insulating substrate (5), and a nickel wider than the circuit width of the base circuit (1) on the top surface of the base circuit (1). (2a) or / and a conductor circuit (3) consisting of a header circuit (2) consisting of gold (2b), and this conductor path (3)
And a resin encapsulating layer (4) surrounding the resin. 2. A copper foil surface (16) located in an insulating path of an insulating substrate (5) on the surface of which a copper foil (11) is arranged is covered with a resist layer (17) to form a conductive path (3). Nickel (2a) and / or gold (2b) was plated on the copper foil surface (18) for the conductive path of the resist-coated substrate where the positioned copper foil surface (18) was exposed to form a header circuit (2). After that, the resist layer (17) is removed to expose the copper foil surface (16), and then the copper foil surface (16) is etched,
Base circuit (1) with a narrower circuit width than the header circuit (2)
Is formed into a printed circuit board, and a resin sealing layer (4) is further formed on the printed circuit board.