{"schema_version":1,"research_id":"eoa_inverse_innovation_exp03_external48_20260801","source_assessment_id":"eoa_inverse_innovation_exp03_opportunity320_20260801","cell_id":"negative_space_design__nanotechnology","selection_stratum":"REJECTION_LOW_BAND_AUDIT","search_queries":["electron beam lithography proximity effect pattern density nearby features critical dimension spacing guard band","lithography design rule keep-out zone critical feature spacing proximity effect","dummy fill exclusion zone lithography critical feature keep out distance pattern density","optical proximity effect dense isolated line critical dimension primary research","patent lithography critical feature guard band unpatterned area proximity exposure","electron beam lithography critical pattern isolated from surrounding pattern spacing method","nanoscale lithography guard band around feature proximity correction spacing","lithography pattern density keep-out zone critical dimension dummy fill exclusion","site:patents.google.com lithography exclusion zone critical dimension pattern","site:patents.google.com electron beam lithography remove neighboring features proximity effect","university nanofabrication facility rates electron beam lithography SEM 2025 official","IRDS 2024 lithography critical dimension uniformity yield official roadmap PDF","ASML computational lithography optical proximity correction official process window yield","open PDK minimum spacing rule lithography manufacturability official"],"sources":[{"source_id":"S1","title":"Two complementary methods to characterize long range proximity effects due to develop loading","publisher":"IBM Research / SPIE","url":"https://research.ibm.com/publications/two-complementary-methods-to-characterize-long-range-proximity-effects-due-to-develop-loading","source_class":"PRIMARY_RESEARCH","publication_date":"2010-12-13","accessed_at":"2026-08-02","claims_supported":["Critical dimension varies with an individual feature's proximity to other exposed areas.","Dense-versus-sparse exposure can degrade CD uniformity.","Electron-beam pattern-density effects can arise from backscattering, chemical flare, and developer loading.","The study used test patterns to characterize proximity effects."]},{"source_id":"S2","title":"US11556058B2: Proximity effect correction in electron beam lithography","publisher":"United States Patent and Trademark Office via Google Patents; assignee Taiwan Semiconductor Manufacturing Company","url":"https://patents.google.com/patent/US11556058B2/en","source_class":"PRIMARY_RESEARCH","publication_date":"2023-01-17","accessed_at":"2026-08-02","claims_supported":["Indirect exposure is higher for features in dense regions and can broaden printed features.","Dense-region and edge-of-dense-region features can exhibit CD nonuniformity.","An established rival calculates neighbor-dependent indirect exposure and adjusts direct electron-beam dose."]},{"source_id":"S3","title":"2024 IRDS Lithography and Patterning Roadmap","publisher":"IEEE International Roadmap for Devices and Systems","url":"https://irds.ieee.org/images/files/pdf/2024/2024IRDS_LITHO.pdf","source_class":"STANDARD","publication_date":"2024","accessed_at":"2026-08-02","claims_supported":["Critical-dimension uniformity, edge-placement error, line-edge roughness, and defects remain major patterning challenges.","Patterning choices depend on yield and cost.","Process, resist, exposure-tool, and mask improvements are all under investigation."]},{"source_id":"S4","title":"Computational lithography","publisher":"ASML","url":"https://www.asml.com/en/products/computational-lithography","source_class":"COMMERCIAL_FIRST_PARTY","publication_date":"n.d.","accessed_at":"2026-08-02","claims_supported":["Physical and chemical effects deform lithographic images.","Computational lithography uses test-wafer-calibrated models to modify masks and processes.","Computational correction is an established manufacturability and yield approach, including in high-volume production."]},{"source_id":"S5","title":"GF180MCU PDK: Design rules for Dummy Metal addition","publisher":"GlobalFoundries PDK Authors","url":"https://gf180mcu-pdk.readthedocs.io/en/latest/physical_verification/design_manual/drm_13_3.html","source_class":"OFFICIAL_PRODUCT_DOCUMENTATION","publication_date":"2022","accessed_at":"2026-08-02","claims_supported":["A production PDK encodes minimum dummy-to-circuit spacing.","The PDK supports a marked exclusion area that prevents dummy-metal generation in critical analog or RF regions.","Removing fill can conflict with density, etch-margin, and CMP requirements."]},{"source_id":"S6","title":"IHP OpenPDK: Main DRC rules","publisher":"IHP Leibniz Institute for High Performance Microelectronics","url":"https://ihp-open-pdk-docs.readthedocs.io/en/latest/verification/drc/02_main_rules.html","source_class":"OFFICIAL_PRODUCT_DOCUMENTATION","publication_date":"n.d.","accessed_at":"2026-08-02","claims_supported":["Foundry-oriented PDKs routinely encode geometry-specific minimum spacing and notch rules.","The PDK encodes larger clearances between filler and functional geometries than some ordinary feature-to-feature spacings.","Pattern-density limits coexist with spacing constraints."]},{"source_id":"S7","title":"US6751785B1: System and method for limiting increase in capacitance due to dummy metal fills utilized for improving planar profile uniformity","publisher":"United States Patent and Trademark Office via Google Patents","url":"https://patents.google.com/patent/US6751785B1/en","source_class":"PRIMARY_RESEARCH","publication_date":"2004-06-15","accessed_at":"2026-08-02","claims_supported":["Prior art designates selected critical nets and creates rule-based exclusion zones around them.","Noncritical dummy fill is placed outside a configurable blocking distance.","The disclosed reason is electrical capacitance and functionality rather than lithographic proximity exposure."]},{"source_id":"S8","title":"Fees","publisher":"Notre Dame Nanofabrication Facility","url":"https://nanofabrication.nd.edu/facility-access/fees/","source_class":"OFFICIAL_ORGANIZATION_DATA","publication_date":"2026","accessed_at":"2026-08-02","claims_supported":["Shared facilities provide EBL, SEM, staff processing, and cleanroom access to trained researchers.","FY2025-2026 rates separately charge cleanroom access, EBL, SEM, staff labor, supplies, and indirect costs.","External EBL staff processing and SEM use are priced on an hourly basis, supporting a bounded coupon without capital-equipment purchase."]}],"problem_evidence":{"support":"MODERATE","rationale":"Primary research and a TSMC technical disclosure support the general causal premise that neighboring exposure and pattern density can change CD and broaden features, while IRDS confirms that CDU and edge-placement control remain important. Evidence is not STRONG for this candidate because the lithography modality, resist, substrate, feature scale, bridging prevalence, and addressable yield loss are unspecified; bridging itself was not directly established by the opened sources.","source_ids":["S1","S2","S3"]},"stakeholder_evidence":{"support":"MODERATE","rationale":"IRDS and ASML document sustained industry demand for dimensional control, manufacturability, and yield, and official PDKs show that process owners already impose layout-density, spacing, and exclusion rules. No source demonstrates stakeholder demand specifically for sacrificing area around critical features or willingness to prefer that intervention over PEC.","source_ids":["S3","S4","S5","S6"]},"prior_art":{"proximity":"SUBSTANTIAL_COLLISION","closest_analogues":[{"name":"Foundry spacing and filler-clearance design rules","similarity":"IHP's PDK encodes geometry-dependent minimum spacing and larger filler-to-functional-feature clearances; this is already a rule-enforced form of reserving unpatterned space around selected geometry.","remaining_difference":"The opened PDK does not attribute these particular clearances to neighbor-exposure reduction or show a matched comparison against PEC for critical-feature CD and electrical yield.","source_ids":["S6"]},{"name":"Critical-area dummy-fill exclusion zones","similarity":"GlobalFoundries provides a marker that excludes dummy generation in critical analog/RF areas and specifies spacing from protected structures; this closely matches selective removal of nonessential geometry plus rule protection.","remaining_difference":"Its stated purposes concern density, etch margin, CMP, and protected circuit classes, not a demonstrated reduction of lithographic proximity exposure around an individually selected critical nanofeature.","source_ids":["S5"]},{"name":"Critical-net blocking exclusion zones","similarity":"US6751785B1 selects only critical nets, draws a configurable exclusion zone, and places noncritical fill outside it, closely matching the candidate's critical-feature selection and protected negative space.","remaining_difference":"The causal target is capacitance/functionality rather than lithographic CD distortion, and the patent does not compare guard widths with neighbor-aware dose correction.","source_ids":["S7"]},{"name":"Neighbor-aware electron-beam proximity-effect correction","similarity":"US11556058B2 models indirect exposure from neighboring features and adjusts direct dose to maintain CD uniformity, matching the candidate's mechanism and nearest rival.","remaining_difference":"It retains neighboring geometry and changes exposure; the candidate instead tests selectively moving or omitting noncritical neighbors and explicitly measures area and connectivity penalties.","source_ids":["S2"]}],"distinctive_claim_remaining":"Within one specified lithography stack, selectively moving or omitting only functionally noncritical neighboring shapes to create a rule-protected guard band may outperform both the packed layout and optimized neighbor-aware dose/bias correction on prespecified CD-error, bridging, and electrical-function endpoints, with benefit exceeding a preset area penalty. This is a process-specific comparative hypothesis, not an established novelty claim.","confidence":"HIGH"},"implementation_evidence":{"support":"MODERATE","rationale":"The intervention can be encoded using established exclusion-marker and spacing-rule concepts, and shared EBL/SEM infrastructure makes a nonproduction coupon technically accessible without buying capital equipment. However, no opened study demonstrates that new guard-band edges improve the candidate's dimensional and functional endpoints, and density/CMP constraints can make geometry removal harmful.","source_ids":["S5","S6","S8","S1"]},"scores":{"meaningful_impact":{"score":3,"rationale":"CDU, EPE, and defects are industry-level patterning concerns, but the candidate supplies no target-process prevalence, magnitude, or attributable yield fraction.","source_ids":["S1","S3"]},"stakeholder_pull":{"score":3,"rationale":"Manufacturers clearly invest in dimensional control and yield, yet no evidence shows demand for this area-consuming intervention rather than established computational correction.","source_ids":["S3","S4"]},"incremental_advantage":{"score":2,"rationale":"Selective spacing is simple and testable, but established neighbor-aware PEC preserves density, while fill removal may violate density, etch, or CMP requirements. Comparative superiority remains unmeasured.","source_ids":["S2","S4","S5"]},"distinctiveness_plausibility":{"score":2,"rationale":"Spacing rules, critical-area fill exclusions, critical-net blocking zones, and neighbor-aware PEC collectively cover most structural and causal elements. Only the process-specific head-to-head functional comparison remains distinct.","source_ids":["S2","S5","S6","S7"]},"technical_implementability":{"score":4,"rationale":"Layout variants, rule markers, EBL fabrication, SEM metrology, and staff processing are all established capabilities. Implementability depends on identifying genuinely removable geometry and a compatible process stack.","source_ids":["S5","S6","S8"]},"adoption_authority_feasibility":{"score":3,"rationale":"A process/layout owner can plausibly authorize a nonproduction coupon and PDK-style rule, but the candidate names no actual organization, qualified facility, or owner willing to accept density and connectivity tradeoffs.","source_ids":["S5","S8"]},"evidence_readiness":{"score":4,"rationale":"The proposed matched coupon has an explicit baseline, PEC rival, guard-width gradient, dimensional and functional endpoints, area constraint, and falsifiers; required fabrication and metrology are commercially accessible through shared facilities.","source_ids":["S1","S2","S8"]},"safety_net_benefit":{"score":2,"rationale":"A guard rule could add geometric process margin, but it supplies no independent functional fallback and can create density, CMP, edge, routing, or connectivity problems.","source_ids":["S5","S6"]},"scalability":{"score":2,"rationale":"A validated rule could be automated in a PDK, but proximity behavior and appropriate width depend on the exposure modality, resist, substrate, geometry, and process window; recurring area penalties may be substantial.","source_ids":["S1","S2","S5","S6"]}},"score_confidence":"MODERATE","costs":{"first_evidence":{"band_2026_usd":"10K_TO_50K","scope":"Preregister and execute one small nonproduction EBL coupon with repeated packed, small-guard, large-guard, and neighbor-aware dose-corrected structures; include layout and PEC preparation, process-owner review, cleanroom and EBL time, resist/substrates/consumables, SEM CD and bridging metrology, limited electrical probing, analysis, documentation, and indirect charges.","confidence":"MODERATE","assumptions":["An existing EBL process, resist stack, PEC capability, electrical test structure, and shared cleanroom are available.","No production photomask or capital equipment is purchased.","One coupon contains sufficient randomized replicated structures for the initial decision.","Engineering and analysis labor, rather than published equipment rates alone, is the largest resource component."],"source_ids":["S8"]},"initial_deployment_startup":{"band_2026_usd":"50K_TO_250K","scope":"Develop a process-specific guard-band rule for a bounded feature class, encode and verify the rule, run several engineering coupons across dose/focus and placement variation, assess density/CMP/connectivity interactions, establish metrology controls, and complete engineering, safety, and change-control review.","confidence":"LOW","assumptions":["Deployment remains within one research or low-volume nanodevice process.","Existing layout-verification and PEC software can be configured rather than newly developed.","No advanced production mask set is required.","The area penalty does not force a full device-architecture redesign."],"source_ids":["S5","S6","S8"]},"operational_launch":{"band_2026_usd":"250K_TO_1M","scope":"Release the rule for one bounded low-volume device family, revise layouts, complete physical and electrical verification, fabricate qualification lots, evaluate process-window and functional yield, train operators, document exceptions, and coordinate process, layout, metrology, quality, and downstream approvals.","confidence":"LOW","assumptions":["Launch is limited to an EBL or similarly flexible low-volume process rather than a leading-edge high-volume optical product.","Existing fabrication, metrology, software, and compliance infrastructure is used.","Mask-set replacement, if any, is modest; a leading-edge production mask revision could exceed this band.","Density loss does not materially reduce sellable die count."],"source_ids":["S3","S5","S8"]},"annual_recurring":{"band_2026_usd":"50K_TO_250K","scope":"Maintain process-specific rules and software, review layout exceptions, monitor CD and electrical control structures, periodically requalify after resist/tool/recipe changes, train users, investigate excursions, and account for bounded sacrificed-area and coordination costs.","confidence":"LOW","assumptions":["The rule applies only to selected critical features on one low-volume line.","No recurring capital purchase or full-mask respin is required.","Process changes requiring major requalification are infrequent.","The economic value of lost area remains modest; high-volume die-area loss could move recurring cost far above this band."],"source_ids":["S5","S6","S8"]}},"verified_pipeline_gates":{"externally_supported_problem":{"status":"YES","reason":"Opened primary and official sources support neighbor- and density-dependent CD distortion and the continuing importance of CDU/EPE control, although target-process prevalence remains unknown.","source_ids":["S1","S2","S3"]},"externally_credible_adopter_or_authorizer":{"status":"UNCERTAIN","reason":"Foundries and nanofabrication facilities are credible implementation settings, but no actual process owner, layout owner, or facility has been identified as willing and authorized to run this candidate's coupon.","source_ids":["S5","S8"]},"distinct_testable_incremental_claim":{"status":"YES","reason":"The remaining claim is a falsifiable comparison of selective guarded geometry with both packed and neighbor-aware dose-corrected layouts under dimensional, functional, connectivity, and area constraints.","source_ids":["S1","S2","S5"]},"bounded_next_evidence_step":{"status":"YES","reason":"One nonproduction coupon with randomized replicated guard-width and PEC comparators is bounded, reversible, and decision-relevant; it does not imply production deployment.","source_ids":["S1","S2","S8"]},"no_unresolved_safety_or_authority_stop":{"status":"YES","reason":"At coupon scale, work can be confined to trained facility users, versioned nonproduction layouts, and approved existing processes, with required contacts and alignment/test structures excluded from removal. Execution remains conditional on joint process/layout authorization.","source_ids":["S5","S8"]},"credible_cost_scope_and_range":{"status":"UNCERTAIN","reason":"Official 2026 shared-facility rates support the first-evidence band and work categories, but the unspecified lithography modality, mask needs, electrical test complexity, qualification breadth, production volume, and economic value of lost area prevent confident deployment and recurring ranges.","source_ids":["S8","S3"]}},"next_evidence_step":"With a named process owner and layout owner, preregister one nonproduction coupon containing randomized matched replicates of four conditions: packed/no PEC, packed/neighbor-aware PEC, small protected guard band, and larger protected guard band. Hold the critical geometry, material stack, nominal process, and measurement method fixed; record local neighbor distance/density, CD error, bridge rate, connectivity, prespecified electrical function, and area penalty. Falsify the problem premise if the uncorrected structures show no reproducible neighbor-distance or density association after placement is controlled. Falsify the intervention if neither guarded condition beats both the packed baseline and PEC rival on the dimensional and functional endpoints within the preset area budget, or if a new guard edge transfers the error elsewhere.","blocking_evidence":["A named lithography modality, resist/substrate stack, feature class, process window, and actual authorizing organization.","Target-process data establishing the prevalence and magnitude of neighbor-associated CD error or bridging.","Matched coupon evidence that a guarded variant beats both packed and neighbor-aware PEC comparators on dimensional and electrical endpoints.","Evidence that neighboring shapes classified as noncritical can be removed or moved without connectivity, density, CMP, alignment, test, or safety consequences.","A prespecified acceptable area penalty and evidence that any benefit exceeds it.","Process-window replication across relevant placements, doses, focus conditions, tools, materials, and feature orientations before rule generalization.","A modality-specific cost model covering masks, software licenses, engineering labor, qualification lots, yield economics, and recurring sacrificed area.","A broader patent and nonpatent freedom-to-operate review if legal novelty or commercialization is later asserted."],"research_disposition":"PRIOR_ART_DIFFERENTIATION_STUDY","world_novelty_boundary":"This bounded search covered electron-beam and optical proximity effects, neighbor-aware PEC, open-foundry spacing rules, dummy-fill exclusion rules, critical-net blocking patents, industry roadmaps, and shared-facility costs. It found substantial collision with established spacing/exclusion and correction practices, but did not find an opened source demonstrating the exact head-to-head claim: selectively removing only noncritical neighbors to improve CD and electrical function over optimized PEC within an area budget. That residual absence is not a world-novelty or freedom-to-operate conclusion; unpublished foundry rules, additional patents, other lithography modalities, and non-English literature were not exhaustively searched."}