Wired circuit board including an insulating layer formed with an opening filled with a conductive portion and producing method thereof
A wired circuit board includes an insulating layer to be formed with an opening extending therethrough in a thickness direction of the wired circuit board, a conductive layer formed on one surface of the insulating layer in the thickness direction and including a one-side terminal portion, an other-side terminal portion formed on the other surface of the insulating layer in the thickness direction, disposed so as to overlap the opening and the one-side terminal portion when projected in the thickness direction, and used to be connected to an electronic element via a conductive adhesive, and a conductive portion filling the opening to provide electrical conduction between the one-side terminal portion and the other-side terminal portion.
1. A wired circuit board, comprising:
an insulating layer formed with an opening extending therethrough in a thickness direction of the wired circuit board;
a conductive layer formed on one surface of the insulating layer in the thickness direction and including a one-side terminal portion;
an other-side terminal portion formed on an opposite surface of the insulating layer in the thickness direction, disposed so as to overlap the opening and the one-side terminal portion when projected in the thickness direction, and used to be connected to an electronic element via a conductive adhesive; and
a conductive portion filling the opening to provide electrical conduction between the one-side terminal portion and the other-side terminal portion, wherein the opening is disposed on an outside of the one-side terminal portion so as to be spaced apart therefrom, and wherein the other-side terminal portion is continuously and integrally formed so as to overlap both the opening and the one-side terminal portion when projected in the thickness direction.
2. A wired circuit board according to claim 1 , wherein the other-side terminal portion has asperities formed in an opposite surface in the thickness direction, and wherein a surface roughness Ra (JIS B 0601:2001) of the opposite surface of the other-side terminal portion formed with the asperities is in a range of 0.05 μm to 5 μm.
3. A wired circuit board according to claim 2 , wherein the asperities are formed at least in a region of the other-side terminal portion which overlaps the one-side terminal portion when projected in the thickness direction.
4. A wired circuit board according to claim 1 , further comprising: a plating layer formed on an opposite surface of the other-side terminal portion in the thickness direction.
5. A wired circuit board according to claim 1 , wherein the electronic element is a piezoelectric element.
6. A method of producing a wired circuit board, comprising:
preparing a metal supporting layer;
forming an insulating layer on one surface of the metal supporting layer in a thickness direction of the wired circuit board so as to form an opening in the insulating layer extending through the insulating layer in the thickness direction;
forming a conductive layer including a one-side terminal portion on one surface of the insulating layer in the thickness direction, while forming a conductive portion on an exposed surface of the metal supporting layer exposed from the opening; and
etching the metal supporting layer to form an other-side terminal portion provided so as to overlap at least the one-side terminal portion and the conductive portion when projected in the thickness direction, electrically conducting with the one-side terminal portion via the conductive portion, and used to be connected to an electronic element via a conductive adhesive, wherein the opening is disposed on an outside of the one-side terminal portion so as to be spaced apart therefrom, and wherein the other-side terminal portion is continuously and integrally formed so as to overlap both the opening and the one-side terminal portion when projected in the thickness direction.
7. A method of producing a wired circuit board according to claim 6 , further comprising: forming asperities in an opposite surface of a region of the metal supporting layer in the thickness direction which overlaps the one-side terminal portion when projected in the thickness direction, wherein a surface roughness Ra (JIS B 0601: 2001) of an opposite surface of the other-side terminal portion formed with the asperities is in a range of 0.05 μm to 5 μm.
8. A method of producing a wired circuit board according to claim 6 , further comprising: forming a plating layer on an opposite surface of the other-side terminal portion in the thickness direction.
9. A wired circuit board according to claim 1 , wherein the other-side terminal portion continuously and integrally includes:
a peripheral edge portion disposed so as to overlap the opening when projected in the thickness direction and to be connected to the conductive portion; and
a terminal recessed portion disposed so as to include the one-side terminal portion when projected in the thickness direction, surrounded by the peripheral edge portion and recessed toward one side of the thickness direction from the peripheral edge portion.