ETCHING AGENT, ETCHING METHOD, AND FORMED LAMINATE AND DEVICE

PROBLEM TO BE SOLVED: To provide an etching agent used for a chemical wet etching method of chemical-resistant crystal material. SOLUTION: The etching agent is provided containing a cryolite (Na3AlF6) and a halogen salt like a potassium tetrafluoroborate (KBF4). The salt exists in the etching agent in sufficient amount for etching a support layer, and can have a melting temperature exceeding about 200°C. The wet etching method includes the steps of contacting the etching agent containing the cryolite and/or the potassium tetrafluoroborate on one or more surfaces of the support layer 130 containing the aluminum oxide of a multilayer laminate, and then etching at least the part of the support layer 130. An independent laminate is provided containing a gallium nitride manufactured by crystal growth on the aluminum oxide support layer 130. COPYRIGHT: (C)2007,JPO&INPIT