Making of micro-miniature electronic components by selective oxidation

Claim 1

A METHOD OF MAKING A MICRO-MINIATURE ELECTRONIC COMPONENT COMPRISING THE STEPS OF: A. FORMING ON A MAJOR SURFACE OF A SUBSTRATE A LAYER OF METAL CAPABLE OF BEING ETCHED AT A RELATIVELY HIGH RATE BY AN ETCHANT AND CAPABLE OF BECOMING RELATIVELY ETCHANT RESISTANT TO AN ETCHANT ON OXIDATION; B. APPLYING OVER THE METAL LAYER A RESIST LAYER SENSITIVE AT LEAST TO ONE TYPE OF RADIATION SELECTED FROM THE GROUP CONSISTING OF PHOTONS AND ELECTRONS; C. DEFINING A DESIRED COMPONENT PATTERN IN THE RESIST LAYER BY SELECTIVELY EXPOSING PORTIONS OF THE RESIST LAYER TO A RADIATION TO WHICH THE LAYER IS SENSITIVE TO DEFINE THE COMPONENT PATTERN BY DIFFERENCE IN SOLUBILITY BETWEEN THE EXPOSED AND UNEXPOSED PORTIONS OF THE LAYER; D. REMOVING THE MORE SOLUBLE PORTIONS OF THE RESIST LAYER TO EXPOSE FIRST PORTIONS OF THE METAL LAYER AND TO LEAVE REMAINING PORTIONS OF THE RESIST LAYER DEFINING THE DESIRED COMPONENT PATTERN; E. APPLYING OVER THE EXPOSED FIRST PORTIONS OF THE METAL LAYER AND THE REMAINING PORTIONS OF THE RESIST LAYER AN OXIDATION MASKING LAYER OF A THICKNESS LESS THAN ABOUT 80 PERCENT OF THE RESIST LAYER THICKNESS, SAID MASKING LAYER BEING RELATIVELY OXIDATION RESISTANT COMPARED TO THE METAL LAYER AND BEING RELATIVELY ETCHABLE COMPARED TO THE METAL LAYER WHEN OXIDIZED; F. REMOVING THE REMAINING PORTIONS OF THE RESIST LAYER AND OXIDATION MASKING LAYER THEREOVER TO EXPOSE SECOND PORTIONS OF THE METAL LAYER DEFINING THE DESIRED COMPONENT PATTERN; G. SELECTIVELY OXIDIZING THE EXPOSED SECOND PORTIONS OF THE METAL LAYER TO FORM A RELATIVELY ETCHANT RESISTANT PORTION IN THE METAL LAYER CORRESPONDING TO THE SECOND PORTION, WHILE THE FIRST PORTIONS OF THE METAL LALYER ARE MASKED AGAINST OXIDATION BY THE MASKING LAYER; AND H. REMOVING REMAINING PORTIONS OF THE OXIDATION MASKING LAYER AND THE UNDERLYING UNOXIDIZED FIRST PORTIONS OF THE METAL LAYER WITH AN ETCHANT TO WHICH THE OXIDIZED PORTIONS OF THE METAL LAYER ARE RESISTANT TO LEAVE OXIDIZED SECOND PORTIONS OF THE METAL LAYER IN THE DESIRED COMPONENT PATTERN DEFINED ORIGINALLY IN THE RESIST LAYER.

Claim 2

A METHOD OF MAKING A MICRO-MINIATURE ELECTRONIC COMPONENT COMPRISING THE STEPS OF: A. FORMING ON A MAJOR SURFACE OF A SUBSTRATE A LAYER OF METAL CAPABLE OF BEING ETCHED AT A RELATIVELY HIGH RATE BY AN ETCHANT AND CAPABLE OF BECOMING RELATIVELY ETCHANT RESISTANT TO AN ETCHANT ON OXIDATION; B. APPLYING OVER THE METAL LAYER A RESIST LAYER SENSITIVE AT LEAST TO ONE TYPE OF RADIATION SELECTED FROM THE GROUP CONSISTING OF PHOTONS AND ELECTRONS; C. DEFINING A DESIRED COMPONENT PATTERN IN THE RESIST LAYER BY SELECTIVELY EXPOSING PORTIONS OF THE RESIST LAYER TO A RADIATION TO WHICH THE LAYER IS SENSITIVE TO DEFINE THE COMPONENT PATTERN BY DIFFERENCE IN SOLUBILITY BETWEEN THE EXPOSED AND UNEXPOSED PORTIONS OF THE LAYER; D. REMOVING THE MORE SOLUBLE PORTIONS OF THE RESIST LAYER TO EXPOSE FIRST PORTIONS OF THE METAL LAYER AND TO LEAVE REMAINING PORTIONS OF THE RESIST LAYER DEFINING THE DESIRED COMPONENT PATTERN; E. APPLYING OVER THE EXPOSED FIRST PORTIONS OF THE METAL LAYER AND THE REMAINING PORTIONS OF THE RESIST LAYER AN OXIDATION MASKING LAYER OF A THICKNESS LESS THAN ABOUT 80 PERCENT OF THE RESIST LAYER THICKNESS, SAID MASKING LAYER BEING RELATIVELY OXIDATION RESISTANT COMPARED TO THE METAL LAYER AND BEING RELATIVELY ETCHABLE COMPARED TO THE METAL LAYER WHEN OXIDIZED; F. REMOVING THE REMAINING PORTIONS OF THE RESIST LAYER AND OXIDATION MASKING LAYER THEREOVER TO EXPOSE SECOND PORTIONS OF THE METAL LAYER DEFINING THE DESIRED COMPONENT PATTERN; G. SELECTIVELY OXIDIZING THE EXPOSED SECOND PORTIONS OF THE METAL LAYER TO FORM A RELATIVELY ETCHANT RESISTANT PORTION IN THE METAL LAYER CORRESPONDING TO THE SECOND PORTION, WHILE THE FIRST PORTIONS OF THE METAL LALYER ARE MASKED AGAINST OXIDATION BY THE MASKING LAYER; AND H. REMOVING REMAINING PORTIONS OF THE OXIDATION MASKING LAYER AND THE UNDERLYING UNOXIDIZED FIRST PORTIONS OF THE METAL LAYER WITH AN ETCHANT TO WHICH THE OXIDIZED PORTIONS OF THE METAL LAYER ARE RESISTANT TO LEAVE OXIDIZED SECOND PORTIONS OF THE METAL LAYER IN THE DESIRED COMPONENT PATTERN DEFINED ORIGINALLY IN THE RESIST LAYER.

Claim 5

A method of making an electromask comprising the steps of: A. forming on a major surface of a quartz substrate a titanium layer; B. applying over the titanium layer an electron resist layer; C. defining in the electron resist layer a desired component pattern by selectively exposing portions of the resist layer to electron radiation to define the component pattern by difference in solubility between the exposed and unexposed portions of the layer; D. removing the more soluble portions of the electron resist layer to expose first portions of the titanium layer and leave remaining portions of the resist layer defining the desired component pattern; E. applying over the exposed first portions of the titanium layer and the remaining portions of the resist layer an oxidation masking layer; F. removing the remaining resist layer and oxidation masking layer thereover to expose second portions of the titanium layer defining the desired component pattern; G. selectively oxidizing the exposed second portions of the titanium layer to form a relatively etchant resistant titanium dioxide portion in the titanium layer corresponding to the second portions, while the first portions of the titanium layer are masked against oxidation by the masking layer; and H. removing the remaining portions of the oxidation masking layer and the underlying first portions of the titanium layer with an etchant to which the titanium dioxide portions of the titanium layer are resistant to leave the oxidized second portions of the titanium layer in the desired component pattern defined originally in the resist layer.

Claim 6

A method of making an electromask comprising the steps of: A. forming on a major surface of a quartz substrate a titanium layer; B. applying over the titanium layer an electron resist layer; C. defining in the electron resist layer a desired component pattern by selectively exposing portions of the resist layer to electron radiation to define the component pattern by difference in solubility between the exposed and unexposed portions of the layer; D. removing the more soluble portions of the electron resist layer to expose first portions of the titanium layer and leave remaining portions of the resist layer defining the desired component pattern; E. applying over the exposed first portions of the titanium layer and the remaining portions of the resist layer an oxidation masking layer; F. removing the remaining resist layer and oxidation masking layer thereover to expose second portions of the titanium layer defining the desired component pattern; G. selectively oxidizing the exposed second portions of the titanium layer to form a relatively etchant resistant titanium dioxide portion in the titanium layer corresponding to the second portions, while the first portions of the titanium layer are masked against oxidation by the masking layer; and H. removing the remaining portions of the oxidation masking layer and the underlying first portions of the titanium layer with an etchant to which the titanium dioxide portions of the titanium layer are resistant to leave the oxidized second portions of the titanium layer in the desired component pattern defined originally in the resist layer.