Reprocessing method of semiconductor substrate, manufacturing method of reprocessed semiconductor substrate, and manufacturing method of soi substrate

A method for manufacturing an SOI substrate, comprising the steps of:

• irradiating a reprocessed semiconductor substrate with second ions to form an embrittlement region in the reprocessed semiconductor substrate;
• bonding the reprocessed semiconductor substrate and a base substrate to each other with an insulating layer interposed therebetween;
• and
• separating the reprocessed semiconductor substrate by a heat treatment to form a semiconductor layer over the base substrate,
• wherein the reprocessed semiconductor substrate is manufactured by a method comprising:
• performing a first etching treatment on a damaged semiconductor substrate comprising a first damaged semiconductor region in a central portion of the damaged semiconductor substrate and a step portion in a peripheral portion of the damaged semiconductor substrate, wherein the step portion is left by separating a part of a semiconductor substrate after an irradiation with first ions and a heat treatment, wherein the step portion includes a second damaged semiconductor region and an insulating layer over the second damaged semiconductor region, and wherein a thickness of the first damaged semiconductor region is thinner than a thickness of the second damaged semiconductor region, so that the insulating layer over the second damaged semiconductor region is removed;
• performing a second etching treatment on the damaged semiconductor substrate, wherein the second etching treatment uses a mixed solution comprising a first substance capable of performing an oxidation of a semiconductor material included in the damaged semiconductor substrate, a second substance capable of performing a dissolution of an oxidized semiconductor material, and a third substance capable of controlling a speed of the oxidation of the semiconductor material and a speed of the dissolution of the oxidized semiconductor material, so that the second damaged semiconductor region is selectively removed with a non-damaged semiconductor region left;
• and
• heating the damaged semiconductor substrate under an atmosphere including hydrogen after performing the second etching treatment.