| 摘要 |
PURPOSE:To enable a semiconductor substrate having superior electric characteristics to be obtained by means of direct bonding, by directly contacting two mirror-polished semiconductor substrates with each other, heating them for integration and, simultaneously therewith or thereafter, heat treating them in an atmosphere of hydrogen at a temperature of 200 deg.C or more. CONSTITUTION:Two mirror-polished semiconductor substrates 1 and 2 are directly contacted closely with each other by their polished surfaces in a clean atmosphere and heated at a temperature of 200 deg.C or more to be integrated. Simultaneously with or after this heating process, the integrated semiconductor substrates are heat treated at a temperature of 200 deg.C or more in an atmosphere of hydrogen. For example, the surfaces to be bonded of two p-type Si substrates are mirror polished. These substrates are treated with H2O2+H2SO4, then boiled in aqua regia and treated with dilute HF so that they are degreased and that any stain film adhered on their surfaces is removed. Subsequently, they are washed with clean water and dehydrated at room temperature. The substrates 11 and 12 thus treated are located in a clean atmosphere and their mirror polished surfaces are closely contacted with each other and bonded together without no foreign matters on the polished surfaces. They are heat-treated within an electric furnace supplied with a flow of hydrogen gas at 1,000 deg.C for 2hr. |
