PLASMA ETCHING

• Main Author: KOSHIO ATSUSHI
• Format: Patent
• Language: English
• Published: 29.03.1991
• 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

PURPOSE:To stabilize plasma state and improve working accuracy by using a parallel planer plasma etching device and carrying out the etching in two separate steps with a high frequency and a low frequency power sources when a silicon dioxide film is etched. CONSTITUTION:Opposed electrodes 2, 3 are disposed in a chamber 1. A semiconductor wafer 6 covered with a silicon dioxide film is placed on an electrode 2 in the chamber 1, wherein a mixed gas of CHF3 and CF4 is controlled to be at a predetermined pressure. In a first step of etching, a contact hole forming part of the silicon dioxide film is etched to about 90% of the film thickness by applying low frequency power between the electrodes 2, 3 from a low frequency power source 5. Then, the power source is switched to a high frequency power source 4, and high frequency power is applied between the electrodes 2, 3 to etch the remaining part of the silicon dioxide film to form the contact hole.