{
  "schema": "semiagora.process-simulation.v1",
  "experiment_id": "SA-PROC-BEOL-CMP-PLANAR-001",
  "title": "CMP removal and planarization",
  "execution_mode": "precomputed-only",
  "model_boundary": "Educational CMP replay. It is not a slurry model, pad model, endpoint controller, copper damascene qualification, or manufacturing-control recipe.",
  "process": {
    "family": "back-end planarization",
    "method": "chemical mechanical planarization",
    "tracked_knobs": [
      "pressure",
      "relative velocity",
      "pattern density",
      "endpoint margin"
    ]
  },
  "preston_teaching_grid": {
    "pressure_kpa": [20, 30, 40],
    "relative_velocity_m_s": [0.6, 0.8, 1],
    "removal_rate_nm_min_matrix": [
      [36, 48, 60],
      [54, 72, 90],
      [72, 96, 120]
    ],
    "note": "Teaching grid using rate proportional to pressure times relative velocity."
  },
  "pattern_density_cases": [
    {
      "id": "low-density-open-field",
      "density_percent": 20,
      "removal_rate_nm_min": 92,
      "dishing_nm": 18,
      "erosion_nm": 7
    },
    {
      "id": "balanced-density",
      "density_percent": 50,
      "removal_rate_nm_min": 80,
      "dishing_nm": 9,
      "erosion_nm": 12
    },
    {
      "id": "high-density-array",
      "density_percent": 80,
      "removal_rate_nm_min": 62,
      "dishing_nm": 5,
      "erosion_nm": 24
    }
  ],
  "radial_uniformity": {
    "radius_fraction": [-1, -0.5, 0, 0.5, 1],
    "normalized_removal_percent": [95, 98, 100, 99, 97]
  },
  "derived_metrics": {
    "max_teaching_removal_rate_nm_min": 120,
    "balanced_density_removal_rate_nm_min": 80,
    "within_wafer_half_range_nonuniformity_percent": 2.56,
    "endpoint_margin_s": 8,
    "public_claim": "CMP needs both removal-rate math and pattern/topography warnings attached to the result."
  },
  "methods": [
    "Use a Preston-style pressure times velocity grid for the first removal-rate comparison.",
    "Keep pattern-density examples separate from blanket removal so dishing and erosion stay visible.",
    "Compute wafer-level nonuniformity from the radial normalized-removal samples.",
    "Treat endpoint margin as a teaching marker, not a control-system implementation."
  ],
  "limitations": [
    "No slurry chemistry, pad asperity model, conditioner state, wafer carrier pressure map, temperature, endpoint sensor, or material stack calibration is modeled.",
    "No copper/barrier/oxide selectivity qualification or damascene recipe is implied.",
    "No yield, defectivity, scratch, corrosion, erosion-control, or production endpoint claim is made.",
    "Measured blanket rates, patterned-wafer metrology, endpoint traces, and rights-clean process notes are required before calibrated claims."
  ],
  "sources": [
    {
      "label": "MIT CMP erosion model paper",
      "url": "https://web.mit.edu/cmp/publications/papers/noh_final.pdf",
      "use": "Public CMP modeling paper discussing Preston-equation removal framing, wafer-level nonuniformity, pattern geometry, and erosion."
    },
    {
      "label": "MIT OCW semiconductor process variation",
      "url": "https://ocw.mit.edu/courses/2-830j-control-of-manufacturing-processes-sma-6303-spring-2008/resources/2-semiconductor-process-variation/",
      "use": "Public process-variation context for temporal, spatial, wafer-level, chip-level, and feature-level variation."
    }
  ]
}