{
  "schema": "semiagora.process-simulation.v1",
  "experiment_id": "SA-PROC-PVD-SPUTTER-UNIFORMITY-001",
  "title": "Sputter deposition thickness uniformity",
  "execution_mode": "precomputed-only",
  "model_boundary": "Educational radial-thickness replay. It is not a calibrated sputter recipe, plasma model, target-erosion model, or film-stress prediction.",
  "process": {
    "family": "physical vapor deposition",
    "method": "magnetron sputtering",
    "nominal_center_thickness_nm": 100,
    "wafer_radius_mm": 50,
    "tracked_knobs": [
      "target-to-substrate geometry",
      "rotation on/off",
      "pressure regime",
      "source profile width"
    ]
  },
  "radius_mm": [-50, -40, -30, -20, -10, 0, 10, 20, 30, 40, 50],
  "cases": [
    {
      "id": "rotating-wafer-reference",
      "label": "Rotating wafer reference",
      "description": "A symmetric replay where rotation averages azimuthal variation and leaves a radial center-edge trend.",
      "normalized_thickness_percent": [92.3, 95.1, 97.4, 98.9, 99.7, 100, 99.7, 98.9, 97.4, 95.1, 92.3],
      "thickness_nm": [92.3, 95.1, 97.4, 98.9, 99.7, 100, 99.7, 98.9, 97.4, 95.1, 92.3],
      "center_to_edge_drop_percent": 7.7,
      "half_range_nonuniformity_percent": 3.97
    },
    {
      "id": "fixed-wafer-wider-plasma",
      "label": "Fixed wafer / wider spread",
      "description": "A deliberately less uniform case used to show why rotation, throw distance, target erosion state, and shielding matter.",
      "normalized_thickness_percent": [84.2, 88.2, 92.3, 96.1, 98.9, 100, 98.9, 96.1, 92.3, 88.2, 84.2],
      "thickness_nm": [84.2, 88.2, 92.3, 96.1, 98.9, 100, 98.9, 96.1, 92.3, 88.2, 84.2],
      "center_to_edge_drop_percent": 15.8,
      "half_range_nonuniformity_percent": 8.52
    }
  ],
  "derived_metrics": {
    "best_case_half_range_nonuniformity_percent": 3.97,
    "best_case_center_to_edge_drop_percent": 7.7,
    "public_claim": "Rotation improves the teaching model by averaging angular variation, but radial nonuniformity remains visible."
  },
  "methods": [
    "Normalize each radial profile to the center point.",
    "Report center-edge drop as center thickness minus absolute-edge thickness.",
    "Report nonuniformity as (max - min) / (2 * mean) over the sampled radius.",
    "Keep the result dimensionless enough to compare concepts before any tool-specific recipe is introduced."
  ],
  "limitations": [
    "No plasma chemistry, sheath model, target erosion, re-sputtering, film stress, grain structure, temperature, or reactive gas kinetics are modeled.",
    "No material-specific deposition rate is claimed.",
    "The 100 nm center thickness is a plotting target, not a process recommendation.",
    "Tool qualification requires measured witness-wafer data and facility-approved recipes."
  ],
  "sources": [
    {
      "label": "UIUC MRL deposition tools",
      "url": "https://mrl.illinois.edu/facilities/research-cores/micronano-fabrication-and-cleanroom/deposition-tools",
      "use": "Public cleanroom context for sputtering, rotating substrate holders, and thin-film deposition tool boundaries."
    }
  ]
}