Method for selectively covering a micro machined surface
AssigneeTelecom Italia S.p.A.
InventorsRenato Conta, Irma Disegna
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Abstract
On a die that has etchings on a surface, firstly a sheet of negative photoresist is laid down which, by means of an exposure and subsequent development, is left only above the etchings; then, upon the negative photoresist, a positive photoresist is applied, which is subjected to exposure and development to produce functional geometries deposited in thin film; subsequently the positive photoresist is removed in a “lift-off” operation, and the negative photoresist is taken off in a plasma operation, thus revealing the etchings.
Claims20
A method for selectively covering a micro machined surface on a die comprising an upper face and at least one etched recess located in the upper face, the method comprising:
- applying a film of negative photoresist onto the upper face, the film of negative photoresist covering the at least one etched recess without filling the at least one etched recess;
- exposing the film of negative photoresist to ultraviolet radiation through a first mask, the first mask having a window coextensive with at least the at least one etched recess, thereby polymerizing a region of the film of negative photoresist covering the at least one etched recess;
- removing a non-polymerized portion of the film of negative photoresist from the upper face, thereby leaving a covering of polymerized film over the at least one etched recess;
- applying a layer of lift off resist over the upper face of the die and over the covering;
- and
- applying a layer of positive photoresist over the layer of lift off resist.
A method for selectively covering a micro machined surface on a die comprising an upper face and at least one etched recess located in the upper face, the method comprising:
- applying a film of negative photoresist onto the upper face, the film of negative photoresist covering the at least one etched recess without filling the at least one etched recess;
- exposing the film of negative photoresist to ultraviolet radiation through a first mask, the first mask having a window coextensive with at least the at least one etched recess, thereby polymerizing a region of the film of negative photoresist covering the at least one etched recess;
- removing a non-polymerized portion of the film of negative photoresist from the upper face, thereby leaving a covering of polymerized film over the at least one etched recess;
- and
- applying a layer of positive photoresist over the upper face of the die and over the covering.
Dependencies are inferred from the claim text.