Thick aluminum etching method

• Main Authors: HUANG RENRUI, ZHU WENMING
• Format: Patent
• Language: Chinese; English
• Published: 20.11.2020
• Subjects: BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLICMATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASSC23 AND AT LEAST ONEPROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25; NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; SEMICONDUCTOR DEVICES

The invention relates to a thick aluminum etching method, which comprises: forming a metal interconnection structure on a wafer, wherein the metal interconnection structure comprises a first buffer layer, a thick aluminum layer and a second buffer layer which are sequentially arranged on the wafer, and a photoresist layer is formed on the second buffer layer; patterning the photoresist layer, andetching the second buffer layer according to the pattern of the photoresist layer; etching the thick aluminum layer with the first proportion thickness, wherein etching gas is nitrogen, chlorine and boron trichloride; and keeping the pressure of the cavity unchanged, reducing the flow of nitrogen and boron trichloride, and etching the remaining thick aluminum layer with the second proportion thickness and the first buffer layer. By comprehensively controlling parameters such as cavity pressure, reaction gas types, flow and the like, the etching rate of the reaction gas to the photoresist is reduced, and finally the se