Etching of Metals Using a Laser and Selected FREON Gases
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
By using an excimer laser to photodissociate certain halogenated methanes (FREON* gases), high resolution etching of metals, such as copper and chromium, can occur at reasonable rates. FREON gases, such as CF2Br2, do not interact with metals such as Cu or Cr. Eximer laser pulses, such as those from KrF at 248 nm or ArF at 193 nm impinging on the FREON gas, produce radical fragments, such as CF2, CF2Br and Br. This photolysis process, in conjunction with surface irradiation, promotes thermal and/or photochemical surface reactions of adsorbed species, causing etching to occur in the regions where the light is striking the metal. The dissociation is a temporary situation, with the fragments not directly involved with the metal continuously recombining to reform stable gases.