| abstract |
(57) [Problem] To use a low-resistance copper film as a wiring material and at a high etching rate by a simple chemical etching method in which the copper film is immersed in an inexpensive and easily available aqueous solution of a reagent in a stationary state. An etchant that can be etched and is less likely to cause abnormal etching or pattern thinning is obtained. SOLUTION: As an etching agent for copper, a hydrogen salt comprising potassium hydrogen sulfate, sodium hydrogen sulfate, ammonium hydrogen sulfate, ammonium dihydrogen phosphate, or ammonium dihydrogen phosphate and an oxidizing agent comprising hydrogen peroxide are contained. Use an aqueous solution. |