Two-Step Quartz Etchback Process
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
An improved quartz etchback process has been developed which reduces cycle time by etching the semiconductor structure with two different gas mixtures. The structure to be planarized in the process consists of a thick layer of planar resist 1 (Fig. 1), a planar quartz layer 2 and the metal line or stud 3 to be exposed by etching. In the previous method, etchback of the wafer took place in a single wafer reactive plasma reactor with essentially 100% tetrafluoromethane CF4, used to achieve the desired etch rate ratio of 1.2 between quartz and resist necessary for planarity. The method described required approximately 4.5 minutes to complete with much of the etching time due to the relatively low initial etch rate of the planar resist in a CF4 discharge.