Self-aligned pattern over a reflective layer
AssigneeInternational Business Machines Corporation
InventorsMichael Dean Caterer, Timothy Harrison Daubenspeck, Thomas George Ference, Edmund Juris Sprogis
Life of this patent
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Abstract
An opening in an insulator on a substrate is self-aligned to a reflective region on the substrate. The opening is formed by shining blanket radiation on photoresist on the insulator and developing to open the resist and insulator. The resist region that is above the reflective region absorbs both incident and reflected radiation, a larger total dose of radiation than is absorbed by resist above non-reflective regions. The incident dose is adjusted to provide a below threshold dose everywhere except to those regions of resist that are above highly reflective regions.
Claims18
A method of forming a self-aligned opening on a semiconductor wafer, the semiconductor wafer having an absorbance, comprising the steps of:
- (a) providing a surface having a first region and a second region, said first region having a first magnitude of an optical property, said second region having a second magnitude of an optical property, there being a difference in said optical property magnitudes between said first and second regions;
- (b) depositing a first permanent layer of insulation on said first and second regions;
- (c) depositing a layer of photoactive material on said layer of insulation on said first and second regions;
- (d) shining equal incident radiation on said photoactive material on said first and second regions wherein said photoactive material on said first and second regions is differentially exposed as a result of said difference in optical property magnitude;
- and
- (e) forming an opening in said layer of photoactive material self-aligned to said first region;
- wherein said first permanent layer of insulation has an absorbance higher than the semiconductor's absorbance for said radiation of said shining step (d) and wherein said first permanent layer of insulation has a thickness sufficient to provide electrical insulation.
A method of forming a self-aligned opening, comprising the steps of:
- (a) providing a surface having a first region and a second region, said first region having a first magnitude of an optical property, said second region having a second magnitude of an optical property, there being a difference in said optical property magnitudes between said first and second regions;
- (b) depositing a layer of insulator on said first and second regions, wherein said insulator has a thickness sufficient to provide electrical insulation;
- (c) depositing a layer of photoactive material on said first and second regions;
- (d) shining equal incident radiation on said photoactive material on said first and second regions wherein said photoactive material on said first and second regions are differentially exposed as a result of said difference in optical property magnitude;
- and
- (e) forming an opening in said layer of photoactive material self-aligned to said first region;
- wherein said first region of said step (a) has a width and said layer of insulator of said step (b) has a thickness, said width being greater than said thickness, and wherein said first region comprises a first wire, said method further comprising a second wire, said second wire having a width less than said first wire, wherein in said forming step (e), forming said opening in said layer of photoactive material above said first wire but not above said second wire.
Dependencies are inferred from the claim text.