Process for selective etching of polymeric materials embodying silicones therein

Claim 1

A method for the selective chemical etching of a cured layer of a silicone-polyimide copolymer material disposed on a surface of a body to open windows therein to expose selected surface portions of the surface thereat including the process steps of: (a) forming a layer of a cured silicone-polyimide copolymer material on a processed body of semiconductor material, the copolymer material consisting of a reaction product of a silicon-free organic diamine, an organic tetracarboxylic dianhydride and a polysiloxane which when cured has the recurring structural units of the formula: ##STR8## with from 5 to 40 mol percent intercondensed structural units of the formula: ##STR9## wherein: R is a divalent hydrocarbon radical; R' is a monovalent hydrocarbon radical; R" is a tetravalent organic radical; Q is a divalent silicon-free organic radical which is the residue of an organic diamine; x is an integer having a value of 1-4, and m and n are integers greater than 1; (b) depositing a layer of titanium metal of a predetermined thickness on the layer of silicone-polyimide copolymer material; (c) depositing a positive photoresist material on the layer of titanium; (d) processing the layer of photoresist material to open one or more windows therein to expose a selected surface area of the layer of titanium metal thereat; (e) chemically etching the exposed titanium metal selectively in fluoboric acid to open one or more windows therein, aligned with the respective windows in the layer of photoresist, to expose selected surface areas of the layer of silicone-polyimide copolymer material thereat, and (f) chemically etching the layer of silicone-polyimide copolymer material selectively in a phenol bearing solution to open one or more windows in the copolymer layer, aligned with the respective windows of the layer of titanium, to expose the selected surface areas of the surface thereat.

Claim 2

A method for the selective chemical etching of a cured layer of a silicone-polyimide copolymer material disposed on a surface of a body to open windows therein to expose selected surface portions of the surface thereat including the process steps of: (a) forming a layer of a cured silicone-polyimide copolymer material on a processed body of semiconductor material, the copolymer material consisting of a reaction product of a silicon-free organic diamine, an organic tetracarboxylic dianhydride and a polysiloxane which when cured has the recurring structural units of the formula: ##STR8## with from 5 to 40 mol percent intercondensed structural units of the formula: ##STR9## wherein: R is a divalent hydrocarbon radical; R' is a monovalent hydrocarbon radical; R" is a tetravalent organic radical; Q is a divalent silicon-free organic radical which is the residue of an organic diamine; x is an integer having a value of 1-4, and m and n are integers greater than 1; (b) depositing a layer of titanium metal of a predetermined thickness on the layer of silicone-polyimide copolymer material; (c) depositing a positive photoresist material on the layer of titanium; (d) processing the layer of photoresist material to open one or more windows therein to expose a selected surface area of the layer of titanium metal thereat; (e) chemically etching the exposed titanium metal selectively in fluoboric acid to open one or more windows therein, aligned with the respective windows in the layer of photoresist, to expose selected surface areas of the layer of silicone-polyimide copolymer material thereat, and (f) chemically etching the layer of silicone-polyimide copolymer material selectively in a phenol bearing solution to open one or more windows in the copolymer layer, aligned with the respective windows of the layer of titanium, to expose the selected surface areas of the surface thereat.