An implantable device having a body of matrix material made up of insoluble collagen fibrils, and disposed therewithin. The invar alloy angles are cut at a radius area eliminating a part of the invar alloy angles covering the stringer foot in order to define an invar alloy piece having no foot. The waveform generator generates a synchronized input trigger signal and aligns the analog output signal with the synchronized input trigger signal by reloading the LUT with a binary address value of zero. By heating the substrate with the wiring formed thereon, a surface of the wiring on the opening and a surface of the wiring other than the wiring on the opening are approximately leveled, and the opening is filled.