PURPOSE: To prevent the displacement of a chip during pressure-pinching with electrodes by a method wherein the opposite surface of an electrode is provided with a part of positioning a diode chip.

CONSTITUTION: The periphery of the opposite surface 12 of one electrode 1 is projected out to the side of the opposite electrode 2 to a degree smaller than the thickness of the chip 3, and its inside is made inclined, resulting in the production of an annular projection 14 triangular in cross-section. At the time of assembly, the electrode 1 is inserted to the hole 51 of the lower mold 5 of carbon with the smaller diameter part 11 upward, and the chip 3 is inserted to the hole 51 and mounted inside the projection 14; then, a glass tube 4 is inserted to the hole 51 and fitted to the electrode smaller diameter part 11. The electrode 2 is inserted to the hole 61 of the upper mold 6 of carbon with the smaller diameter part 21 upward, and the upper mold 6 is reversed and stacked on the lower mold 5, when the smaller diameter part 21 penetrates into the glass tube 4 and abuts against the chip 3. On heating by imposing a load P on the electrode 2 with a rod 7 through the hole, the tube 4 reduces in diameter and welds to the smaller diameter parts 11 and 21. At this time, the chip 3 does not displace, but is pinched by pressure contact with the electrodes 1 and 2 under the shrinkage of the tube 4 on cooling.