Semiconductor pattern delineation by sputter etching process

Abstract

A layer is patterned by sputter etching using a photoresist as a sputter-etch-mask and using a thin metal layer between the mask and the layer or layer-system to be patterned. The metal layer is extremely thin and consists of a metal that is itself useless as a sputter-etch-mask. The process is especially important in the manufacture of semiconductor devices.

What is claimed is: 
     
       1. A method of manufacturing a pattern from a layer or a series of layers of material removable by sputter etching from a substrate, said method comprising applying to said layer or series of layers a .Iadd.thin .Iaddend.coating of a metal removable by sputter etching at a rate which is .[.from.]. at least .[.one half.]. .Iadd.of the same order as .Iaddend.the rate of .[.that of.]. .Iadd.removal of .Iaddend.the underlying layer or of the average of the underlying series of layers, .Iadd.a rate of the same order as another rate being defined as being at least half and at most twice the other rate, .Iaddend.said .Iadd.thin .Iaddend.metal coating having a thickness of less than 0.5 μm and being thinner than said underlying layer or series of layers, providing a sputter etch photoresist mask of desired configuration on selected portions of said thin metal coating to define a pattern of exposed areas, removing said thin .Iadd.metal .Iaddend.coating from said exposed areas and sputter etching the resultant exposed areas of said layer or series of layers to thereby remove the layer or series of layers in said exposed areas and then removing by etching said thin .Iadd.metal .Iaddend.coating present in the areas protected by said photoresist mask and thereby lifting off said photoresist mask from the resultant pattern. 
     
     
       2. A method as claimed in claim 1, characterized in that the thin metal coating has a thickness of at most 0.3 μm. 
     
     
       3. A method as claimed in claim 1 wherein the exposed areas of the thin metal coating are removed by a selective etching treatment after the formation of the photoresist pattern and preceding the sputter etching treatment. 
     
     
       4. A method as claimed in claim 2, wherein the exposed areas of the thin metal coating are removed by a sputter etching treatment after the formation of the photoresist pattern. 
     
     
       5. A method as claimed in claim 1 wherein the layer or the system of layers has a thickness of more than 0.5 μm and a gap is locally provided therein with a width of at most 2 μm.