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EP0257255A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Photoresist process for reactive ion etching of metal patterns for semiconductor devices

Assignee: International Business Machines Corp
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Filing: 1987-07-07
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Granted: —
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Expires: 2007-07-07
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Abstract

Abstract The process is based upon applying a layer of release agent which is a solution of a polysulfone constituent and a dye, applied to the surface of a polysilicon layer. Thereafter, the photoresist layer can be applied on top of the release agent layer. Then, the photo­resist can be optically exposed and developed and its alignment measured. If the alignment of the resultant photoresist structures is found to be incorrect, rework can be easily accomplished by dissolving the release agent in a suitable solvent. This allows the existing photoresist structures to be removed. Then the rework cycle can continue by applying a new layer of the release agent and dye solution and followed by a new photoresist layer. If the original photoresist layer or the reworked photoresist layer is found to have been properly aligned, then the normal processing steps can continue. The process also provides for an improved control over back reflected and diffracted light during the optical exposure step. The presence of a dye which is selected to have an absorption cross-section which peaks at an optical wavelength approximately equal to the emission peak for the wavelength of the exposure light, enables any portion of the exposure light which passes through the photoresist and into the release layer, to be absorbed before it has a chance to be reflected or diffracted back up into the photoresist layer. This enables the photoresist to be uniformly exposed even when it passes over structures which lie beneath the release layer and which might otherwise cause unwanted reflection or diffraction of the expo­sure light.

Inventors

  • 👤 Hans Adolf Protschka

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-01 18:53
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/20; H10P76/204; H10P76/2041; G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/091; G03F7/11; H10P14/00; H10P14/60; H10P14/68; H10P14/683; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P76/2043

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 162 words
Reactive ion etching processing comprising the steps of: depositing a release layer comprising a release agent mixed with an absorptive dye to a surface to be etched; applying a layer of photoresist to said release layer; exposing said photoresist to a patterned light source so that light which penetrates through said photoresist layer will be absorbed in said release layer; developing said photoresist; measuring the alignment of the remaining photo­resist structures and initiating a rework cycle if misalignment is measured; said rework cycle including dissolving said release layer to remove said residual photoresist structures and applying a replacement layer of said release layer followed by a replacement layer of said photoresist; continuing the processing if said alignment measurement is found to be good, by reactive ion etching said release layer using said residual photoresist structure as a mask; reactive ion etching said surface masked by said photoresist layer and said release layer; dissolving said release layer to remove said remaining photoresist structures.
Claim 2
Dependent Claim 162 words
Reactive ion etching processing comprising the steps of: depositing a release layer comprising a release agent mixed with an absorptive dye to a surface to be etched; applying a layer of photoresist to said release layer; exposing said photoresist to a patterned light source so that light which penetrates through said photoresist layer will be absorbed in said release layer; developing said photoresist; measuring the alignment of the remaining photo­resist structures and initiating a rework cycle if misalignment is measured; said rework cycle including dissolving said release layer to remove said residual photoresist structures and applying a replacement layer of said release layer followed by a replacement layer of said photoresist; continuing the processing if said alignment measurement is found to be good, by reactive ion etching said release layer using said residual photoresist structure as a mask; reactive ion etching said surface masked by said photoresist layer and said release layer; dissolving said release layer to remove said remaining photoresist structures.
Claim 3
Dependent Claim 77 words
Process of claim 1 wherein said release layer is composed of a solution of between 4 to 15 percent by weight of poly-ether-sulfone powder, between 35 to 55 percent by weight of N-methyl-pyrrolidone, and between 35 to 55 percent by weight of a diluent, this solution then having dissolved therein a suitable dye whose optical absorption coefficient has a maximum substantially the same as the maximum emission wavelength for the light used in said photoresist exposure step.
Claim 4
Dependent Claim 16 words
Process of claim 2 wherein said absorptive dye is composed of orosol yellow 4GN monoazo dye.
Claim 5
Dependent Claim 70 words
Process of claim 2 wherein said release agent is composed of a solution of approximately 8.5 percent by weight of poly-ether-sulfone powder, approximately 45.75 percent by weight of N-methyl-­pyrrolidone, and approximately 45.75 percent by weight of diethyleneglycol-dimethylether, this solution then having dissolved therein a suitable dye whose optical absorption coefficient has a maximum substantially the same as the maximum emission wavelength for the light used in said photoresist exposure step.
Claim 6
Dependent Claim 97 words
Release agent for use in a reactive ion etching process to enable improved operation of a positive photoresist deposited on top of a layer of the release agent, the composition of which comprises: a solution of between 4 to 15 percent by weight of poly-ether-sulfone powder, between 35 to 55 percent by weight of N-methyl-pyrrolidone, and between 35 to 55 percent by weight of a diluent, this solution then having dissolved therein a suitable dye whose optical absorption coefficient has a maximum substantially the same as the maximum emission wavelength for light used in photoresist exposure operations.
Claim 7
Dependent Claim 97 words
Release agent for use in a reactive ion etching process to enable improved operation of a positive photoresist deposited on top of a layer of the release agent, the composition of which comprises: a solution of between 4 to 15 percent by weight of poly-ether-sulfone powder, between 35 to 55 percent by weight of N-methyl-pyrrolidone, and between 35 to 55 percent by weight of a diluent, this solution then having dissolved therein a suitable dye whose optical absorption coefficient has a maximum substantially the same as the maximum emission wavelength for light used in photoresist exposure operations.
Claim 8
Dependent Claim 18 words
Composition of claim 5 which further comprises: said absorptive dye is composed of orosol yellow 4GN monoazo dye.
Claim 9
Dependent Claim 91 words
Release agent for use in a reactive ion etching process to enable improved operation of a positive photoresist deposited on top of a layer of the release agent, the composition of which comprises: a solution of approximately 8.5 percent by weight of poly-ether-sulfone powder, approximately 45.75 percent by weight of N-methyl-pyrrolidone, and approximately 45.75 percent by weight of di-­ethyleneglycol-dimethylether, this solution then having dissolved therein a suitable dye whose optical absorption coefficient has a maximum substantially the same as the maximum emission wavelength for the light used in photoresist exposure operations.
Claim 10
Dependent Claim 91 words
Release agent for use in a reactive ion etching process to enable improved operation of a positive photoresist deposited on top of a layer of the release agent, the composition of which comprises: a solution of approximately 8.5 percent by weight of poly-ether-sulfone powder, approximately 45.75 percent by weight of N-methyl-pyrrolidone, and approximately 45.75 percent by weight of di-­ethyleneglycol-dimethylether, this solution then having dissolved therein a suitable dye whose optical absorption coefficient has a maximum substantially the same as the maximum emission wavelength for the light used in photoresist exposure operations.

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