CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 37 U.S.C. § 371 to International Patent Application No. PCT/JP2020/011152, filed Mar. 13, 2020, which claims priority to and the benefit of Japanese Patent Application No. 2019-086053, filed Apr. 26, 2019. The contents of these applications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a structure manufacturing method, a structure manufacturing apparatus and an intermediate structure.

DESCRIPTION OF RELATED ART

Group III nitrides such as gallium nitride (GaN) are used as materials for manufacturing semiconductor devices such as light emitting devices and transistors.

Photoelectrochemical (PEC) etching has been proposed as an etching technique for forming various structures on group III nitrides such as GaN (see, for example, Non-Patent Document 1). The PEC etching is wet etching with less damage than general dry etching, and is preferable because an apparatus is simple, compared to special dry etching with less damage such as neutral particle beam etching (see, for example, Non-Patent Document 2) and atomic layer etching (see, for example, Non-Patent Document 3).

PRIOR ART DOCUMENT

Patent Document

[Non-Patent Document 1] J. Murata et al., “Photo-electrochemical etching of free-standing GaN wafer surfaces grown by hydride vapor phase epitaxy”, Electrochimica Acta 171 (2015) 89-95[Non-Patent Document 2] S. Samukawa, JJAP, 45 (2006) 2395.[Non-Patent Document 3] T. Faraz, ECS J. Solid Stat. Scie. & Technol., 4, N5023 (2015).

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

An object of the present invention is to provide a technique capable of suppressing a temporal fluctuation of an etching condition in PEC etching applied to group III nitrides.

Means for Solving the Problem

According to an aspect of the present invention, there is provided a structure manufacturing method, including:

preparing an etching target with at least one surface comprising group III nitride;

then in a state where the etching target is immersed in an etching solution containing peroxodisulfate ions;

irradiating the surface of the etching target with light through the etching solution, and generating sulfate ion radicals from the peroxodisulfate ions and generating holes in the group III nitride, thereby etching the group III nitride,

wherein in the etching of the group III nitride, the etching solution remains acidic during a period for etching the group III nitride by making the etching solution acidic at a start of etching the group III nitride, and

the etching is performed, with a resist mask formed on the surface.

According to another aspect of the present invention, there is provided an intermediate structure, including:

an etching target with at least one surface comprising group III nitride; and

a resists mask formed on the surface,

and configured to be immersed in an acidic etching solution containing peroxodisulfate ions, with the resist mask formed on the surface.

Advantage of the Invention

There is provided a technique capable of suppressing a temporal fluctuation of an etching condition in PEC etching applied to group III nitrides.

