Thin film capacitor, circuit board incorporating the same, and thin film capacitor manufacturing method

A circuit board incorporating a thin film capacitor, the thin film capacitor comprising:

• a lower electrode layer;
• an upper electrode layer;
• and
• a dielectric layer disposed between the lower electrode layer and the upper electrode layer,
• wherein the dielectric layer has a through hole,
• wherein the upper electrode layer has a connection part connected to the lower electrode layer through the through hole and an electrode part insulated from the connection part by a slit,
• wherein a surface of the lower electrode layer that contacts the connection part through the through hole includes an annular area positioned along an inner wall surface of the through hole and a center area surrounded by the annular area, and
• wherein the annular area is lower in surface roughness than the center area.

A method of manufacturing a thin film capacitor, the method comprising:

• forming a dielectric layer on a surface of a lower electrode layer;
• forming a through hole in the dielectric layer;
• forming an upper electrode layer on a surface of the dielectric layer;
• and
• forming a slit in the upper electrode layer to form a connection part connected to the lower electrode layer through the through hole and an electrode part insulated from the connection part by the slit,
• wherein the forming the through hole is performed by wet-etching such that an annular part, which constitutes a part of the surface of the lower electrode layer that is exposed to the through hole and positioned along an inner wall surface of the through hole is lower in surface roughness than a center area surrounded by the annular area.