Patent ID: 6346418
Filing Date: 2002-02-12
Classification: G01N,G03F,Y10T

Abstract:
A method for evaluating a ratio of metal in photoresist material, comprising:putting said photoresist into a reaction tube and adding a first nitric acid solution into said reaction tube to form a first mixed liquid, wherein said photoresist comprises a metal; heating said first mixed liquid in a microwave oven for digesting a non-metal portion of said photoresist; monitoring a pressure of said reaction tube during the heating of the first mixed liquid; adding hydrogen peroxide into said reaction tube to form a second mixed liquid and heating said second mixed liquid to continue digesting the photoresist; monitoring a pressure of said reaction tube during the heating of the second mixed liquid; evaporating residual liquid left after heating of said second mixed liquid by hot plate heating to form a residue containing said metal; forming a solution by adding a second nitric acid solution to said residue; and analyzing said solution by ICP-MS to measure the ratio of said metal.