Chip parts

A chip transformer including:

• a substrate that has an element formation surface;
• a thermal oxide film formed in the substrate;
• a primary coil formation trench and a secondary coil formation trench that are formed in the thermal oxide film by digging down from the element formation surface and that are formed in the shape of a spiral in a plan view when seen in a normal direction perpendicular to the element formation surface;
• a primary coil that is formed with a first conductive member embedded within the primary coil formation trench;
• a secondary coil that is formed with a second conductive member embedded within the secondary coil formation trench;
• a first insulating film formed on an upper surface of the substrate;
• a second insulating film formed on an upper surface of the first insulating film;
• and
• a first electrode and a second electrode disposed on the element formation surface, one end portion of the primary coil connected to the first electrode and an opposite end portion of the primary coil connected to the second electrode,
• wherein the primary coil and the secondary coil are formed to penetrate and pass through the first insulating film,
• wherein the first electrode penetrates and passes through the second insulating film to contact the one end portion of the primary coil,
• wherein the second electrode penetrates and passes through the second insulating film to contact the opposite end portion of the primary coil, and
• wherein side surfaces and a bottom surface of the primary coil and the secondary coil are surrounded by the thermal oxide film.