| 摘要 |
PROBLEM TO BE SOLVED: To improve the performance of a thin-film transistor at a lower manufacturing cost by, at formation of a metal wiring, selectively replacing at least a part of the wiring of semiconductor which is formed in advance with a metal through a electrochemical replacement reaction. SOLUTION: An impurity is injected into the region of an active layer 4 which does not overlap a gate electrode 6, and the impurity injected under heat is activated to form a source region 7 and a drain region 8. A gate insulating film over the region is removed by etching into offset form with a width, for example, 1μm from the end of the gate electrode left alone. A substrate is submerged in a mixed water solution containing copper nitrate and ammonium fluoride. Since the ionization tendency of silicon is higher than copper, the silicon atom on the surface is replaced with copper atom so that the silicon atom as deep as, from exposed source/drain surface, 15 nm, for example, is replaced with copper atom, with a copper thin film 9 selectively deposited on the surface of source/drain region. Then the substrate is annealed to bake the copper thin film 9.
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