Tool to provide integrated circuit masks with accurate dimensional compensation of patterns

• US 10,210,295 B2
• Filed: 01/30/2017
• Issued: 02/19/2019
• Est. Priority Date: 11/25/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Rosenbluth, Alan E.
• Primary Examiner(s): Ngo, Brian
• Application Number:
  US15/419,396
• Publication Number:
  US 20170147733A1
• Time in Patent Office: 750 Days
• Field of Search: 716 51, 716 52, 716 53, 716 54, 716 55
• CPC Class Codes: G03F 1/36 Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
• CPC Class Codes: G03F 7/70091 Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

Disclosed are mask definition tools, apparatus, methods, systems and computer program products configured to process data representing a semiconductor fabrication mask. A non-limiting example of a method includes performing a decomposition process on a full Transmission Cross Coefficient (TCC) using coherent optimal coherent systems (OCS) kernels; isolating a residual TCC that remains after some number of coherent kernels are extracted from the full TCC; and performing at least one decomposition process on the residual TCC using at least one loxicoherent system. The loxicoherent system uses a plurality of distinct non-coherent kernel functions and is a compound system containing a paired coherent system and an incoherent system that act in sequence. An output of the coherent system is input as a self-luminous quantity to the incoherent system, and the output of the incoherent system is an output of the loxicoherent system.

Claims

1. A tool to process data representing input integrated circuit patterns of a semiconductor fabrication mask to be used in projection lithography, comprising:

a frame generation module configured to partition each region of a starting mask that is organized into separated regions of mask content into overlapped frames of mask data;

a coherent system engine comprised of an optimal coherent systems (OCS) engine having an input to receive the overlapped frames of mask data of the starting mask and an output to provide a full Transmission Cross Coefficient (TCC); and

an incoherent system engine having an input connected to the output of the OCS engine and an output that provides a final mask definition for use during fabrication of an integrated circuit, where a loxicoherent system is comprised of a pair of the OCS engine and the incoherent system engine, where the incoherent system engine is configured to;

form a residual TCC by removing certain coherent system kernels from the full TCC;

match the residual TCC with a sum of multiplied lower-dimensioned kernels that are separated along axes that are rotated in a doubled domain between mask content axes in the doubled domain;

decompose at least one low-dimensioned kernel lying within the doubled-domain in the mean-frequency direction into a product of coherent system apertures serving to filter the mask content;

select as an intensity kernel at least one low-dimensioned kernel lying along the doubled domain axis in a difference-frequency direction; and

adjust mask fragments by iterating operations across one or more processors.

2. The tool as in claim 1, where the iterated operations comprise determining loxicoherent system contributions to an image intensity at target edge positions by

applying incoherent intensity kernels to squared mask transmissions through the coherent system apertures that have been filtered by the mask filters;

determining the image intensity at target edge positions by adding the loxicoherent contributions to the sum of intensities from the coherent systems;

moving mask fragments adjacent to target edge positions whose intensity is lower than the intensity at the edge of an anchoring feature in a direction towards a darker side of the adjacent target edge;

moving mask fragments adjacent to target edge positions whose intensity is higher than the intensity at the edge of the anchoring feature in a direction towards a brighter side of the adjacent target edge;

modifying edge positions within frame overlap regions to reconcile the position movements made in the frames that overlap; and

terminating the mask fragment adjustment when the intensities at all target edge positions match that of the anchoring feature to within a tolerance value.

3. The tool as in claim 1, where the pair of the coherent system engine and the incoherent system engine operate in sequence, with an output of the OCS engine being input as a self-luminous quantity to the incoherent system engine, and with the output of the incoherent system engine being an output of the loxicoherent system.

4. The tool as in claim 1, where lens apertures of the OCS engine are Fourier transforms of optimal coherent systems kernels obtained by carrying out an eigendecomposition process on a full Transmission Cross Coefficient.

5. The tool as in claim 1, where lens apertures of the OCS engine and the incoherent system engine of the loxicoherent system are obtained by isolating a residual Transmission Cross Coefficient that remains after a chosen set of coherent kernels in the OCS engine set are extracted from the full Transmission Cross Coefficient;

and by then performing at least one decomposition process on the residual Transmission Cross Coefficient using the incoherent system engine.

6. The tool as in claim 1, where a first/primary loxicoherent system is selected to match portions of the Transmission Cross Coefficient that are recalcitrant to matching by a paired OCS engine.

7. An apparatus, comprising:

an Optimal Coherent Systems (OCS) system engine having an input to receive a starting mask and an output to provide a full Transmission Cross Coefficient (TCC); and

a loxicoherent system engine having an input connected to the output of the OCS system engine and an output to provide a mask for use during fabrication of an integrated circuit, said loxicoherent system engine configured to;

form a residual TCC by removing preferred coherent system kernels from the full TCC;

decompose the residual TCC as a sum of lower-dimensioned kernels that are separated along axes that are rotated between mask content axes in a doubled domain;

decompose at least one low-dimensioned kernel lying within the doubled-domain in the mean-frequency direction into a product of mask filters;

select as an intensity kernel at least one low-dimensioned kernel lying along a doubled-domain axis in a difference-frequency direction; and

iteratively adjust mask fragments.

8. The apparatus as in claim 7, where the apparatus iteratively adjusts the mask fragments by:

determining loxicoherent system contributions to an image intensity at target edge positions by applying the intensity kernels to squared mask transmissions that have been filtered by the mask filters;

determining the image intensity at target edge positions by adding the loxicoherent contributions to the sum of intensities from the preferred coherent systems;

moving mask fragments adjacent to target edge positions whose intensity is lower than the intensity at the edge of the anchoring feature in a direction towards a darker side of the adjacent target edge;

moving mask fragments adjacent to target edge positions whose intensity is higher than the intensity at the edge of the anchoring feature in a direction towards a brighter side of the adjacent target edge; and

terminating mask fragment adjustment when the intensities at all target edge positions match that of an anchoring feature to within a tolerance value.