1. Field of the Invention
The present invention relates to a circuit module and a manufacturing method for the same. More specifically, the present invention relates to a circuit module including electronic components mounted on a board, and a manufacturing method for the circular module.
2. Description of the Related Art
As an invention related to a prior-art circuit module and a manufacturing method for the same, there are known a circuit module and a manufacturing method for the same, which are disclosed in Japanese Unexamined Patent Application Publication No. 2008-42152. The manufacturing method for the circuit module, disclosed in Japanese Unexamined Patent Application Publication No. 2008-42152, will be described below with reference to the drawings. FIGS. 14A-14E are sectional views illustrating the manufacturing method for a circuit module 500, which is disclosed in Japanese Unexamined Patent Application Publication No. 2008-42152.
First, as illustrated in FIG. 14A, electronic components 504 are mounted on a board 502. Next, as illustrated in FIG. 14B, an insulating layer 506 is formed so as to cover a principal surface of the board 502 and the electronic components 504. Next, as illustrated in FIG. 14C, cut grooves 508 are formed. On that occasion, at the bottom of each of the cut grooves 508, a tip 508a is formed as a groove having a narrower width than that of the cut groove 508. Next, as illustrated in FIG. 14D, a shield layer 510 is formed by applying an electrically conductive resin to both the insulating layer 506 and the cut grooves 508. Finally, the board 502 and the shield layer 510 are cut by a dicing machine at a cutting width W that is larger than a width of the tip 508a. Consequently, as illustrated in FIG. 14E, the board in the collective (multi-module) form is divided into the individual circuit modules 500.
According to the above-described manufacturing method for the circuit module 500, when the shield layer 510 is formed, air in the cut grooves 508 is caused to reside in the tips 508a. Because the tips 508a are cut away when the multi-module board is divided into the individual circuit modules 500, a possibility that air may remain between the shield layer 510 and each of the board 502 and the insulating layer 506. As a result, adhesion of the shield layer 510 to the board 502 and the insulating layer 506 is increased.
However, the principal surface of the insulating layer 506, on which the shield layer 510 is formed, is flat as illustrated in FIGS. 14A-14E. When the electrically conductive resin in a paste-like state is applied onto the flat insulating layer 506, the applied resin tends to spread overly and to become too thin. Therefore, the manufacturing method for the circuit module 500 accompanies with a risk that a defect area where the electrically conductive resin is not coated may occur in the shield layer 510.