Mounting substrate, method for manufacturing a mounting substrate, and mounted structure including an electronic component

1. A mounting substrate comprising:

a substrate having a front surface;

a first connection electrode and a second connection electrode formed at an interval on the front surface of the substrate, and each having a facing surface facing each other across a facing region separating the facing surfaces of the first and second connection electrodes, and the first and second connection electrodes to be electrically connected to an electronic component;

a resist film formed on the front surface of the substrate so as to cover a peripheral edge portion of the first connection electrode and a peripheral edge portion of the second connection electrode, and including an uneven portion formed in the facing region so as to selectively cover and expose the facing surfaces of the first and second connection electrodes and having different lengths in a facing direction of the first and second connection electrodes when viewed in plan;

a first conductive bonding material arranged on the first connection electrode and to be connected to the electronic component;

a second conductive bonding material arranged on the second connection electrode and to be connected to the electronic component; first recess portions each defined by the uneven portion of the resist film along the facing surface of the first connection electrode, and each receiving an excess portion of the first conductive bonding material that flows out from the first connection electrode due to melting flows; and

second recess portions each defined by the uneven portion of the resist film along the facing surface of the second connection electrode, and each receiving an excess portion of the second conductive bonding material that flows out from the second connection electrode due to melting flows.

2. The mounting substrate according to claim 1 , wherein the first conductive bonding material covers the facing surface of the first connection electrode in the first recess portions, and

the second conductive bonding material covers the facing surface of the second connection electrode in the second recess portions.

3. The mounting substrate according to claim 1 , wherein the first recess portions expose the front surface of the substrate, and

the second recess portions expose the front surface of the substrate.

4. The mounting substrate according to claim 1 , wherein the uneven portion of the resist film includes a first portion covering the facing surfaces of the first and second connection electrodes and having a first length in the facing direction, and a second portion exposing the facing surfaces of the first and second connection electrodes and having a second length less than the first length of the first portion in the facing direction.

5. The mounting substrate according to claim 1 , wherein the second recess portions are formed line-symmetrically with respect to the first recess portions in regard to a line orthogonal to the facing direction when viewed in plan.

6. A mounted structure comprising:

a substrate having a front surface;

a first connection electrode and a second connection electrode formed at an interval on the front surface of the substrate and each having a facing surface facing each other across a facing region separating the facing surfaces of the first and second connection electrodes;

a resist film formed on the front surface of the substrate so as to cover a peripheral edge portion of the first connection electrode and a peripheral edge portion of the second connection electrode, and including an uneven portion formed in the facing region so as to selectively cover and expose the facing surfaces of the first and second connection electrodes and having different lengths in a facing direction of the first and second connection electrodes when viewed in plan;

an electronic component electrically connected to the first and second connection electrodes;

a first conductive bonding material formed on the first connection electrode, and electrically and mechanically connected to the electronic component;

a second conductive bonding material formed on the second connection electrode, and electrically and mechanically connected to the electronic component;

first recess portions each defined by the uneven portion of the resist film along the facing surface of the first connection electrode, and each receiving an excess portion of the first conductive bonding material that flows out from the first connection electrode due to melting flows; and

second recess portions each defined by the uneven portion of the resist film along the facing surface of the second connection electrode, and each receiving an excess portion of the second conductive bonding material that flows out from the second connection electrode due to melting flows.

7. The mounted structure according to claim 6 , wherein the first conductive bonding material covers the facing surface of the first connection electrode in the first recess portions, and

the second conductive bonding material covers the facing surface of the second connection electrode in the second recess portions.

8. The mounted structure according to claim 6 , wherein the first recess portions expose the front surface of the substrate, and

the second recess portions expose the front surface of the substrate.

9. The mounted structure according to claim 6 , wherein the uneven portion of the resist film includes a first portion covering the facing surfaces of the first and second connection electrodes and having a first length in the facing direction, and a second portion exposing the facing surfaces of the first and second connection electrodes and having a second length less than the first length of the first portion in the facing direction.

10. The mounting structure according to claim 6 , wherein the second recess portions are formed line-symmetrically with respect to the first recess portions in regard to a line orthogonal to the facing direction when viewed in plan.