| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the damage in the thickness of a wafer with low cost and to make the wafer an almost complete flat plane immediately regarding the surface condition of the wafer after peeling a thin film crystal, by removing a porous layer remaining part on the wafer by passing current using the wafer as a positive pole in a hydrofluoric acid solution after peeling the thin film crystal. SOLUTION: The whole surface of a porous layer remaining part 104 is brushed with a brush 106 made of fur to remove dust or flake 107. After this, current of 1.0 A is passed with a galvanostat in a solution of pure HF:isopropyl alcohol (IPA):water=1:6:4 (volume ratio), with a spacing of 5 cm from a platinum counter electrode 109. As a result, in about thirty minutes, broken pieces 110 of the porous layer come up in the solution. After passing current for another one minute, the substrate is taken out from the solution, is washed with water and is dried. Although there is faint cloud on the surface of the wafer which is taken out, the surface has metallic gloss and is in the almost original state.</p> |
