Method and system for reducing overlay errors within exposure fields by APC control strategies
AssigneeAdvanced Micro Devices, Inc.
InventorsRolf Seltmann, Bernd Schulz, Fritjof Hempel, Uwe Schulze
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Abstract
By taking into consideration tool-specific distortion signatures and reticle-specific placement characteristics in an alignment control system, the control quality of sophisticated APC strategies may be significantly enhanced. Respective correction data may be established on the basis of any combinations of tool/reticles and layers to be aligned to each other, which may modify the respective target values of alignment parameters used for controlling the alignment process on the basis of standard overlay measurement data obtained from dedicated overlay marks.
Claims19
A method, comprising:
- generating overlay correction data for a plurality of different combinations of a first device layer and a second device layer of a microstructure device, said first device layer being defined by one or more first photomasks, said second device layer being defined by one or more second photomasks, said first and second device layers being formed by using a plurality of lithography tools, said overlay compensation data obtained from a first plurality of measurement positions within said first and second photomasks;
- forming said first device layer on a first product substrate using one of said first photomasks and one of said plurality of lithography tools;
- and
- aligning one of said second photomasks, used in one of said plurality of lithography tools, to said first device layer formed on said first product substrate by using said overlay correction data and an overlay measurement data obtained from a second plurality of measurement positions of a previously processed substrate having formed thereon said first and second layers, said second plurality of measurement positions being less than said first plurality of measurement positions.
A method, comprising:
- defining a map of overlay data for a plurality of lithography tool/reticle combinations for forming a first device layer and aligned thereto a second device layer of a microstructure device using respective two of said lithography tool/reticle combinations, said map being based on a first plurality of spatially distributed measurement positions;
- obtaining overlay measurement data from a first product substrate having formed thereon said first and second device layers, said overlay measurement data being obtained from a second plurality of spatially distributed measurement positions, said second plurality being less than said first plurality;
- and
- controlling aligning, with respect to said first device layer formed on a second product substrate using a first lithography tool/reticle combination comprising a reticle for said first device layer, of said second device layer to be formed by a second lithography tool/reticle combination comprising a reticle for said second device layer on the basis of said map of overlay data and said overlay measurement data.
Dependencies are inferred from the claim text.