Plasma Etching Code Examples

Working Code for Common Etching Tasks

Example Index

Example 1: Basic Reactor Setup C

Initialize a complete plasma reactor with all subsystems.

#include "plasmaetch.h"
#include <stdio.h>
#include <stdlib.h>

int main() {
    // Define reactor geometry
    ReactorConfig config = {
        .chamber_volume = 50.0,
        .electrode_area = 0.12,
        .electrode_gap = 0.025,
        .reactor_type = REACTOR_ICP,
        .chamber_material = "Aluminum",
        .coil_turns = 5,
        .coil_radius = 0.18
    };
    
    // Create gas delivery system
    GasSystem gases = createGasSystem();
    addGasLine(&gases, GAS_CF4, 0.0, 200.0);
    addGasLine(&gases, GAS_O2, 0.0, 100.0);
    addGasLine(&gases, GAS_AR, 0.0, 500.0);
    
    // Configure vacuum system
    VacuumSystem vacuum = {
        .turbo_pump_speed = 500.0,
        .backing_pump_speed = 10.0,
        .base_pressure = 1e-7,
        .throttle_valve = true
    };
    
    // Initialize reactor
    PlasmaReactor reactor = initializeReactor(config, gases, vacuum);
    
    // Configure RF power
    RFGenerator source_rf = {
        .frequency = 13.56e6,
        .max_power = 3000.0,
        .matching_network = AUTO_MATCH
    };
    
    RFGenerator bias_rf = {
        .frequency = 2.0e6,
        .max_power = 500.0,
        .matching_network = AUTO_MATCH
    };
    
    attachRFGenerator(&reactor, &source_rf, RF_SOURCE);
    attachRFGenerator(&reactor, &bias_rf, RF_BIAS);
    
    // Add diagnostics
    addDiagnostic(&reactor, DIAGNOSTIC_OES);
    addDiagnostic(&reactor, DIAGNOSTIC_INTERFEROMETRY);
    
    // Verify operation
    SafetyStatus safety = runSafetyChecks(&reactor);
    
    if (safety.all_ok) {
        printf("Reactor initialized successfully!\n");
        printReactorStatus(&reactor);
    } else {
        printf("Reactor initialization failed!\n");
        return -1;
    }
    
    // Cleanup
    shutdownReactor(&reactor, SHUTDOWN_NORMAL);
    
    return 0;
}
Expected Output:
Reactor initialized successfully!
Reactor Status:
  Type: ICP
  Volume: 50.0 L
  Base Pressure: 1.00e-07 Torr
  Source RF: 13.56 MHz, 0-3000 W
  Bias RF: 2.00 MHz, 0-500 W
  Status: READY

Example 2: Silicon Dioxide Etch Recipe C

Complete oxide etching process with endpoint detection.

#include "plasmaetch.h"

void oxide_etch_example(PlasmaReactor* reactor) {
    // Define substrate stack
    Substrate wafer = {
        .diameter = 300.0,
        .layers = {
            {.material = MAT_PHOTORESIST, .thickness = 1500.0},
            {.material = MAT_SIO2, .thickness = 500.0},
            {.material = MAT_SI, .thickness = 1e6}
        },
        .num_layers = 3
    };
    
    // Set process parameters
    ProcessParams params = {
        .pressure = 15.0,
        .source_power = 1200.0,
        .bias_power = 180.0,
        .chf3_flow = 40.0,
        .cf4_flow = 10.0,
        .ar_flow = 300.0,
        .chuck_temperature = 20.0,
        .he_backside_pressure = 8.0
    };
    
    // Configure endpoint detection
    EndpointConfig endpoint = {
        .method = ENDPOINT_OES,
        .wavelength = 704.0,
        .threshold = 0.15,
        .overetch = 20.0
    };
    
    // Setup and stabilize
    printf("Setting up process...\n");
    setProcessParameters(reactor, params);
    setGasFlows(reactor, createGasMix(
        GAS_CHF3, 40.0,
        GAS_CF4, 10.0,
        GAS_AR, 300.0
    ));
    setPressure(&reactor->vacuum, params.pressure);
    
    // Ignite plasma
    printf("Igniting plasma...\n");
    PlasmaState plasma = ignitePlasma(reactor, 800.0, 3.0);
    
    if (plasma.status != PLASMA_STABLE) {
        printf("Plasma ignition failed!\n");
        return;
    }
    
    // Stabilize
    delay(30.0);
    
    // Load wafer
    printf("Loading wafer...\n");
    loadWafer(reactor, &wafer);
    setChuckVoltage(reactor, 1500.0);
    
    // Process with endpoint
    printf("Starting etch process...\n");
    EtchResult result = runEtchProcess(reactor, &wafer, endpoint);
    
    // Display results
    printf("\n=== Etch Results ===\n");
    printf("Etch time: %.1f seconds\n", result.etch_time);
    printf("Etch rate: %.1f nm/min\n", result.etch_rate);
    printf("Uniformity: %.2f%% (3σ)\n", result.uniformity_3sigma);
    printf("Selectivity SiO2:Si: %.1f:1\n", result.selectivity_oxide_si);
    printf("Selectivity SiO2:PR: %.1f:1\n", result.selectivity_oxide_pr);
    printf("Sidewall angle: %.1f degrees\n", result.profile.sidewall_angle);
    
    // Unload
    unloadWafer(reactor);
    
    // Shutdown
    rampPower(&reactor->source_rf, 0.0, 5.0);
    rampPower(&reactor->bias_rf, 0.0, 5.0);
    stopGasFlows(reactor);
}

Key Points:

  • CHF3/CF4 chemistry provides balanced F/C ratio for selectivity
  • Ar dilution improves uniformity and ion bombardment
  • OES at 704 nm monitors fluorine emission for endpoint
  • 20% overetch ensures complete oxide removal

Example 3: DRIE Bosch Process C

Deep reactive ion etching with alternating etch/passivation cycles.

#include "plasmaetch.h"

typedef struct {
    ProcessParams etch_step;
    ProcessParams pass_step;
    int num_cycles;
    double etch_per_cycle;
} BoschRecipe;

void drie_bosch_example(PlasmaReactor* reactor) {
    // Define Bosch recipe
    BoschRecipe recipe;
    
    // Etch step (SF6)
    recipe.etch_step = (ProcessParams){
        .pressure = 20.0,
        .source_power = 1500.0,
        .bias_power = 15.0,
        .sf6_flow = 130.0,
        .o2_flow = 13.0,
        .temperature = 20.0,
        .duration = 7.0
    };
    
    // Passivation step (C4F8)
    recipe.pass_step = (ProcessParams){
        .pressure = 20.0,
        .source_power = 1500.0,
        .bias_power = 0.0,
        .c4f8_flow = 85.0,
        .temperature = 20.0,
        .duration = 5.0
    };
    
    recipe.num_cycles = 100;
    recipe.etch_per_cycle = 1.0;  // um
    
    printf("DRIE Bosch Process\n");
    printf("Target depth: %.1f um\n", recipe.num_cycles * recipe.etch_per_cycle);
    printf("Etch/Pass times: %.1f/%.1f seconds\n", 
           recipe.etch_step.duration, recipe.pass_step.duration);
    
    // Execute cycles
    for (int cycle = 0; cycle < recipe.num_cycles; cycle++) {
        // Etch step
        setProcessParameters(reactor, &recipe.etch_step);
        setGasFlows(reactor, createGasMix(
            GAS_SF6, 130.0,
            GAS_O2, 13.0
        ));
        ignitePlasma(reactor, 1000.0, 1.0);
        delay(recipe.etch_step.duration);
        stopPlasma(reactor);
        stopGasFlows(reactor);
        delay(0.5);  // Purge
        
        // Passivation step
        setProcessParameters(reactor, &recipe.pass_step);
        setGasFlows(reactor, createGasMix(GAS_C4F8, 85.0));
        ignitePlasma(reactor, 1000.0, 1.0);
        delay(recipe.pass_step.duration);
        stopPlasma(reactor);
        stopGasFlows(reactor);
        delay(0.5);  // Purge
        
        // Progress
        if ((cycle + 1) % 10 == 0) {
            double depth = (cycle + 1) * recipe.etch_per_cycle;
            double time_elapsed = (cycle + 1) * 
                (recipe.etch_step.duration + recipe.pass_step.duration + 1.0);
            printf("Cycle %d/%d | Depth: ~%.1f um | Time: %.1f min\n", 
                   cycle + 1, recipe.num_cycles, depth, time_elapsed / 60.0);
        }
    }
    
    printf("\nDRIE process complete!\n");
}

Optimization Tips:

  • Reduce etch time for smaller scallops (smoother sidewalls)
  • Increase passivation time for higher aspect ratios
  • Add O2 to etch step to control isotropy
  • Lower bias power reduces undercut

Example 4: OES Endpoint Detection C

Optical emission spectroscopy for real-time endpoint determination.

#include "plasmaetch.h"

void oes_endpoint_example(PlasmaReactor* reactor) {
    // Initialize OES detector
    OESDetector oes = {
        .wavelength_range = {200.0, 900.0},
        .resolution = 0.5,
        .integration_time = 100,
        .num_channels = 4
    };
    
    initializeOES(reactor, &oes);
    
    // Configure monitoring channels
    addOESChannel(&oes, 0, 704.0, 2.0);  // F atom
    addOESChannel(&oes, 1, 251.0, 2.0);  // Si atom
    addOESChannel(&oes, 2, 777.0, 2.0);  // O atom  
    addOESChannel(&oes, 3, 486.0, 2.0);  // H atom
    
    // Calibrate baseline
    printf("Calibrating OES baseline...\n");
    ProcessParams baseline_params = {
        .pressure = 15.0,
        .source_power = 1200.0,
        .bias_power = 0.0,
        .chf3_flow = 40.0,
        .ar_flow = 300.0
    };
    
    setProcessParameters(reactor, baseline_params);
    startPlasma(reactor);
    delay(30.0);
    
    OESBaseline baseline = calibrateOESBaseline(&oes, 10.0);
    
    for (int i = 0; i < oes.num_channels; i++) {
        printf("Channel %d (%.1f nm): Baseline = %.3f\n", 
               i, oes.channels[i].wavelength, baseline.values[i]);
    }
    
    // Set endpoint criteria
    EndpointCriteria criteria = {
        .channel = 1,              // Si emission channel
        .threshold = 0.20,         // 20% change
        .method = ENDPOINT_DERIVATIVE,
        .smoothing = 5,
        .confirmation_time = 2.0
    };
    
    setEndpointCriteria(&oes, &criteria);
    
    // Monitor during etch
    printf("\nStarting etch with OES endpoint...\n");
    bool endpoint_detected = false;
    double etch_time = 0.0;
    
    // Enable bias for actual etch
    setProcessParameter(reactor, "bias_power", 180.0);
    
    while (!endpoint_detected && etch_time < 600.0) {
        delay(0.1);
        etch_time += 0.1;
        
        // Get OES signals
        double f_signal = getOESSignal(&oes, 0);
        double si_signal = getOESSignal(&oes, 1);
        double o_signal = getOESSignal(&oes, 2);
        
        // Check endpoint
        endpoint_detected = checkEndpoint(&oes, &criteria);
        
        // Display every second
        if (fmod(etch_time, 1.0) < 0.11) {
            printf("Time: %5.1fs | F: %.3f | Si: %.3f | O: %.3f %s\n",
                   etch_time, f_signal, si_signal, o_signal,
                   endpoint_detected ? " << ENDPOINT" : "");
        }
    }
    
    if (endpoint_detected) {
        printf("\nEndpoint detected at %.1f seconds\n", etch_time);
        
        // Overetch
        double overetch_time = etch_time * 0.20;
        printf("Overetching for %.1f seconds...\n", overetch_time);
        delay(overetch_time);
    }
    
    stopPlasma(reactor);
}

Example 5: Uniformity Analysis C

Measure and analyze etch uniformity across wafer.

#include "plasmaetch.h"
#include <math.h>

void uniformity_analysis_example() {
    // Generate 49-point measurement map
    int num_sites = 49;
    MeasurementSite sites[49];
    generateWaferMap(sites, num_sites, 300.0);  // 300mm wafer
    
    // Simulate measurements (in real use, get from metrology)
    for (int i = 0; i < num_sites; i++) {
        // Example: center-fast pattern with some noise
        double r = sqrt(sites[i].x * sites[i].x + sites[i].y * sites[i].y);
        sites[i].etch_rate = 250.0 - 0.3 * r + random_normal(0, 2.0);
    }
    
    // Calculate uniformity metrics
    UniformityMetrics metrics = analyzeUniformity(sites, num_sites);
    
    printf("=== Uniformity Analysis ===\n");
    printf("Mean etch rate: %.2f nm/min\n", metrics.mean);
    printf("Std deviation: %.2f nm/min\n", metrics.std_dev);
    printf("Range: %.2f nm/min\n", metrics.range);
    printf("3-sigma uniformity: %.2f%%\n", metrics.three_sigma);
    printf("Min rate: %.2f nm/min at (%.1f, %.1f)\n", 
           metrics.min_value, metrics.min_x, metrics.min_y);
    printf("Max rate: %.2f nm/min at (%.1f, %.1f)\n",
           metrics.max_value, metrics.max_x, metrics.max_y);
    
    // Identify pattern
    UniformityPattern pattern = identifyPattern(sites, num_sites);
    printf("\nDetected pattern: ");
    
    switch (pattern) {
        case CENTER_FAST:
            printf("CENTER-FAST\n");
            printf("Recommendation: Reduce source power or increase pressure\n");
            break;
        case EDGE_FAST:
            printf("EDGE-FAST\n");
            printf("Recommendation: Increase source power or reduce pressure\n");
            break;
        case RADIAL_GRADIENT:
            printf("RADIAL GRADIENT\n");
            printf("Recommendation: Adjust gas distribution or temperature\n");
            break;
        case UNIFORM:
            printf("UNIFORM\n");
            printf("Process is well-optimized\n");
            break;
        default:
            printf("COMPLEX/UNKNOWN\n");
            break;
    }
    
    // Generate wafer map
    saveWaferMap(sites, num_sites, "uniformity_map.csv");
    printf("\nWafer map saved to uniformity_map.csv\n");
}

Example 6: Selectivity Optimization C

Optimize chemistry for maximum selectivity.

#include "plasmaetch.h"

void selectivity_optimization_example(PlasmaReactor* reactor) {
    // Test different F/C ratios
    printf("=== Selectivity Optimization ===\n\n");
    
    typedef struct {
        double chf3_flow;
        double cf4_flow;
        double o2_flow;
        double fc_ratio;
    } ChemistryPoint;
    
    ChemistryPoint chemistries[] = {
        {50.0, 0.0, 0.0, 3.0},    // High F/C - fast etch
        {40.0, 10.0, 0.0, 3.2},   // Balanced
        {30.0, 5.0, 5.0, 3.4},    // With O2
        {40.0, 0.0, 0.0, 3.0},    // CHF3 only
        {20.0, 20.0, 0.0, 3.5}    // More CF4
    };
    
    int num_points = sizeof(chemistries) / sizeof(ChemistryPoint);
    
    // Test substrates
    Substrate oxide_wafer = createTestWafer(MAT_SIO2, 1000.0);
    Substrate si_wafer = createTestWafer(MAT_SI, 1000.0);
    Substrate pr_wafer = createTestWafer(MAT_PHOTORESIST, 1000.0);
    
    printf("Testing %d chemistry points...\n\n", num_points);
    
    for (int i = 0; i < num_points; i++) {
        printf("Point %d: CHF3=%.0f CF4=%.0f O2=%.0f (F/C=%.1f)\n",
               i + 1, 
               chemistries[i].chf3_flow,
               chemistries[i].cf4_flow,
               chemistries[i].o2_flow,
               chemistries[i].fc_ratio);
        
        // Set chemistry
        ProcessParams params = {
            .pressure = 15.0,
            .source_power = 1200.0,
            .bias_power = 180.0,
            .chf3_flow = chemistries[i].chf3_flow,
            .cf4_flow = chemistries[i].cf4_flow,
            .o2_flow = chemistries[i].o2_flow,
            .ar_flow = 300.0,
            .temperature = 20.0
        };
        
        setProcessParameters(reactor, params);
        
        // Etch each material
        double er_oxide = measureEtchRate(reactor, &oxide_wafer, 60.0);
        double er_si = measureEtchRate(reactor, &si_wafer, 60.0);
        double er_pr = measureEtchRate(reactor, &pr_wafer, 60.0);
        
        // Calculate selectivities
        double sel_oxide_si = er_oxide / er_si;
        double sel_oxide_pr = er_oxide / er_pr;
        
        printf("  Oxide: %.1f nm/min\n", er_oxide);
        printf("  Si:    %.1f nm/min\n", er_si);
        printf("  PR:    %.1f nm/min\n", er_pr);
        printf("  Selectivity SiO2:Si = %.1f:1\n", sel_oxide_si);
        printf("  Selectivity SiO2:PR = %.1f:1\n\n", sel_oxide_pr);
    }
    
    printf("Recommendation: Use Point 3 (CHF3=30, CF4=5, O2=5) for best selectivity\n");
}

Example 7: Profile Simulation Python

Simulate feature profile evolution using Python bindings.

import plasmaetch as pe
import numpy as np
import matplotlib.pyplot as plt

# Define feature
feature = pe.Feature(
    type='trench',
    width=0.25,  # um
    depth=0.0,
    mask_thickness=0.5,
    mask_material='photoresist'
)

# Plasma conditions
plasma = pe.PlasmaConditions(
    ion_flux=1e16,
    neutral_flux=5e17,
    ion_energy=250.0,
    ion_angular_spread=2.0,
    neutral_to_ion_ratio=50.0
)

# Simulation config
config = pe.SimConfig(
    timesteps=100,
    timestep=1.0,
    mesh_resolution=5.0,
    method='levelset'
)

# Run simulation
print("Running profile simulation...")
profile = pe.simulate_profile(feature, plasma, config)

# Plot results
plt.figure(figsize=(10, 6))
plt.plot(profile.x, profile.y, 'b-', linewidth=2)
plt.xlabel('Lateral Position (um)')
plt.ylabel('Depth (um)')
plt.title(f'Etch Profile: Depth={profile.depth:.2f}um, Angle={profile.angle:.1f}deg')
plt.grid(True)
plt.savefig('profile_simulation.png')

print(f"Depth: {profile.depth:.2f} um")
print(f"Sidewall angle: {profile.angle:.1f} degrees")
print(f"ARDE factor: {profile.arde:.3f}")

Example 8: Multi-Step Recipe C

Complex multi-step process with different conditions.

void multi_step_recipe_example(PlasmaReactor* reactor, Substrate* wafer) {
    printf("=== Multi-Step Etch Process ===\n\n");
    
    // Step 1: Breakthrough (remove native oxide)
    printf("Step 1: Breakthrough\n");
    ProcessParams breakthrough = {
        .pressure = 20.0,
        .source_power = 1000.0,
        .bias_power = 300.0,
        .cf4_flow = 50.0,
        .ar_flow = 100.0,
        .duration = 10.0
    };
    runProcessStep(reactor, wafer, breakthrough);
    
    // Step 2: Main etch (high rate)
    printf("Step 2: Main Etch\n");
    ProcessParams main_etch = {
        .pressure = 15.0,
        .source_power = 1500.0,
        .bias_power = 200.0,
        .chf3_flow = 40.0,
        .cf4_flow = 10.0,
        .ar_flow = 300.0,
        .duration = 120.0
    };
    runProcessStep(reactor, wafer, main_etch);
    
    // Step 3: Soft landing (reduce damage)
    printf("Step 3: Soft Landing\n");
    ProcessParams soft_land = {
        .pressure = 10.0,
        .source_power = 800.0,
        .bias_power = 100.0,
        .chf3_flow = 30.0,
        .ar_flow = 200.0,
        .duration = 20.0
    };
    runProcessStep(reactor, wafer, soft_land);
    
    // Step 4: Overetch (ensure complete removal)
    printf("Step 4: Overetch\n");
    ProcessParams overetch = {
        .pressure = 15.0,
        .source_power = 1200.0,
        .bias_power = 150.0,
        .chf3_flow = 35.0,
        .cf4_flow = 5.0,
        .ar_flow = 250.0,
        .duration = 30.0
    };
    runProcessStep(reactor, wafer, overetch);
    
    printf("\nMulti-step process complete\n");
}

Example 9: Data Logging and Export C

Comprehensive data logging for process tracking.

#include "plasmaetch.h"
#include <time.h>

typedef struct {
    time_t timestamp;
    ProcessParams params;
    EtchResult result;
    PlasmaState plasma;
} ProcessLog;

void data_logging_example(PlasmaReactor* reactor) {
    // Open log file
    FILE* logfile = fopen("process_log.csv", "w");
    
    // Write header
    fprintf(logfile, "Timestamp,Pressure,Source_Power,Bias_Power,");
    fprintf(logfile, "Etch_Rate,Uniformity,Selectivity,DC_Bias,");
    fprintf(logfile, "Reflected_Power\n");
    
    // Process loop
    for (int wafer = 0; wafer < 25; wafer++) {
        ProcessLog log;
        log.timestamp = time(NULL);
        
        // Get process parameters
        log.params = getCurrentParams(reactor);
        
        // Run etch
        log.result = runEtchProcess(reactor, &wafers[wafer], endpoint);
        
        // Get plasma state
        log.plasma = getPlasmaState(reactor);
        
        // Write to log
        struct tm* timeinfo = localtime(&log.timestamp);
        fprintf(logfile, "%04d-%02d-%02d %02d:%02d:%02d,",
                timeinfo->tm_year + 1900,
                timeinfo->tm_mon + 1,
                timeinfo->tm_mday,
                timeinfo->tm_hour,
                timeinfo->tm_min,
                timeinfo->tm_sec);
        
        fprintf(logfile, "%.1f,%.0f,%.0f,%.1f,%.2f,%.1f,%.1f,%.1f\n",
                log.params.pressure,
                log.params.source_power,
                log.params.bias_power,
                log.result.etch_rate,
                log.result.uniformity_3sigma,
                log.result.selectivity_oxide_si,
                log.plasma.dc_bias,
                log.plasma.reflected_power);
        
        printf("Wafer %d logged\n", wafer + 1);
    }
    
    fclose(logfile);
    printf("\nProcess log saved to process_log.csv\n");
}

Example 10: Batch Processing C

High-throughput batch processing with continuous plasma.

void batch_processing_example(PlasmaReactor* reactor, Substrate* wafers, int num_wafers) {
    printf("=== Batch Processing ===\n");
    printf("Total wafers: %d\n\n", num_wafers);
    
    // Batch configuration
    BatchConfig config = {
        .continuous_plasma = true,
        .seasoning_frequency = 100,
        .wafer_to_wafer_time = 120.0
    };
    
    // Start continuous plasma
    if (config.continuous_plasma) {
        ProcessParams params = getOptimizedParams();
        setProcessParameters(reactor, params);
        ignitePlasma(reactor, 1000.0, 5.0);
        printf("Continuous plasma mode enabled\n");
    }
    
    // Process wafers
    time_t start_time = time(NULL);
    int wafers_processed = 0;
    
    while (wafers_processed < num_wafers) {
        // Seasoning check
        if (wafers_processed > 0 && 
            wafers_processed % config.seasoning_frequency == 0) {
            printf("\n--- Running seasoning wafer ---\n");
            Substrate seasoning_wafer = createSeasoningWafer();
            runEtchProcess(reactor, &seasoning_wafer, 300.0);
        }
        
        // Load wafer
        loadWafer(reactor, &wafers[wafers_processed]);
        
        // Process
        EtchResult result = runEtchProcess(reactor, &wafers[wafers_processed], endpoint);
        
        // Log
        logWaferResult(wafers_processed, &result);
        
        // Unload
        unloadWafer(reactor);
        
        wafers_processed++;
        
        // Status update
        if (wafers_processed % 25 == 0) {
            time_t elapsed = time(NULL) - start_time;
            double throughput = (double)wafers_processed / (elapsed / 3600.0);
            printf("\nProgress: %d/%d wafers (%.1f wph)\n", 
                   wafers_processed, num_wafers, throughput);
        }
    }
    
    // Stop continuous plasma
    if (config.continuous_plasma) {
        stopPlasma(reactor);
    }
    
    // Summary
    time_t total_time = time(NULL) - start_time;
    double final_throughput = (double)num_wafers / (total_time / 3600.0);
    
    printf("\n=== Batch Complete ===\n");
    printf("Total wafers: %d\n", num_wafers);
    printf("Total time: %ld seconds (%.1f hours)\n", total_time, total_time / 3600.0);
    printf("Throughput: %.1f wafers/hour\n", final_throughput);
}

Example 11: Chamber Cleaning C

Automated chamber cleaning procedure.

void chamber_clean_example(PlasmaReactor* reactor) {
    printf("=== Chamber Cleaning Procedure ===\n\n");
    
    // Clean recipe
    ProcessParams clean = {
        .pressure = 100.0,
        .source_power = 1500.0,
        .bias_power = 0.0,
        .o2_flow = 200.0,
        .temperature = 60.0
    };
    
    printf("Step 1: O2 plasma clean (10 min)\n");
    setProcessParameters(reactor, clean);
    setGasFlows(reactor, createGasMix(GAS_O2, 200.0));
    ignitePlasma(reactor, 1000.0, 3.0);
    delay(600.0);  // 10 minutes
    stopPlasma(reactor);
    
    printf("Step 2: Purge with N2\n");
    stopGasFlows(reactor);
    purgeWithN2(reactor, 60.0);
    
    printf("Step 3: Measure chamber state\n");
    double polymer = measureChamberPolymer(reactor);
    printf("Residual polymer: %.1f nm\n", polymer);
    
    if (polymer < 10.0) {
        printf("Chamber clean PASSED\n");
    } else {
        printf("Additional cleaning required\n");
    }
}

Example 12: Process DOE Python

Design of experiments for process optimization.

import plasmaetch as pe
import numpy as np
from scipy.optimize import minimize

# Define parameter ranges
params_ranges = {
    'source_power': (1000, 1500),
    'bias_power': (100, 300),
    'pressure': (10, 30),
    'chf3_flow': (30, 50)
}

# Generate DOE points (factorial design)
doe_points = pe.generate_factorial_doe(params_ranges, levels=3)

print(f"Running {len(doe_points)} DOE experiments...\n")

results = []
for i, point in enumerate(doe_points):
    print(f"Experiment {i+1}/{len(doe_points)}")
    result = pe.run_experiment(point)
    results.append(result)
    print(f"  Etch rate: {result.etch_rate:.1f} nm/min")
    print(f"  Uniformity: {result.uniformity:.2f}%")
    print(f"  Selectivity: {result.selectivity:.1f}:1\n")

# Fit response surface
model = pe.fit_response_surface(doe_points, results)

# Optimize for targets
targets = {
    'etch_rate': 250.0,
    'uniformity': 2.0,
    'selectivity': 20.0
}

optimized = pe.optimize_parameters(model, targets)

print("Optimized Parameters:")
for key, value in optimized.items():
    print(f"  {key}: {value:.1f}")
Back to Main Project

Example 13: Real-Time Monitoring C

Real-time process monitoring with live data streaming.

#include "plasmaetch.h"
#include <pthread.h>

typedef struct {
    PlasmaReactor* reactor;
    bool running;
    FILE* datafile;
} MonitorThread;

void* monitoring_thread(void* arg) {
    MonitorThread* mon = (MonitorThread*)arg;
    
    fprintf(mon->datafile, "Time,Pressure,DC_Bias,Reflected_Power,OES_F,OES_Si\n");
    
    double elapsed = 0.0;
    while (mon->running) {
        // Collect real-time data
        double pressure = getPressure(&mon->reactor->vacuum);
        double dc_bias = getDCBias(mon->reactor);
        double refl_power = getReflectedPower(&mon->reactor->source_rf);
        double oes_f = getOESIntensity(mon->reactor, 704.0);
        double oes_si = getOESIntensity(mon->reactor, 251.0);
        
        // Log to file
        fprintf(mon->datafile, "%.1f,%.2f,%.1f,%.1f,%.3f,%.3f\n",
                elapsed, pressure, dc_bias, refl_power, oes_f, oes_si);
        
        // Display
        printf("\r[%.1fs] P=%.1fmT  Vdc=%.0fV  Refl=%.1fW  F=%.3f  Si=%.3f  ",
               elapsed, pressure, dc_bias, refl_power, oes_f, oes_si);
        fflush(stdout);
        
        usleep(100000);  // 100ms
        elapsed += 0.1;
    }
    
    return NULL;
}

void realtime_monitoring_example(PlasmaReactor* reactor) {
    printf("=== Real-Time Process Monitoring ===\n\n");
    
    // Setup monitoring thread
    MonitorThread monitor = {
        .reactor = reactor,
        .running = true,
        .datafile = fopen("realtime_data.csv", "w")
    };
    
    pthread_t thread_id;
    pthread_create(&thread_id, NULL, monitoring_thread, &monitor);
    
    // Run process
    Substrate wafer = createTestWafer(MAT_SIO2, 500.0);
    EtchResult result = runEtchProcess(reactor, &wafer, 180.0);
    
    // Stop monitoring
    monitor.running = false;
    pthread_join(thread_id, NULL);
    fclose(monitor.datafile);
    
    printf("\n\nMonitoring complete - data saved to realtime_data.csv\n");
    printf("Etch rate: %.1f nm/min\n", result.etch_rate);
}

Example 14: Recipe Import/Export C

Import and export recipes in multiple formats.

#include "plasmaetch.h"
#include <json-c/json.h>

void export_recipe_json(ProcessParams* params, const char* filename) {
    json_object* root = json_object_new_object();
    
    json_object_object_add(root, "pressure", 
        json_object_new_double(params->pressure));
    json_object_object_add(root, "source_power",
        json_object_new_double(params->source_power));
    json_object_object_add(root, "bias_power",
        json_object_new_double(params->bias_power));
    
    json_object* gases = json_object_new_object();
    json_object_object_add(gases, "CHF3", json_object_new_double(params->chf3_flow));
    json_object_object_add(gases, "CF4", json_object_new_double(params->cf4_flow));
    json_object_object_add(gases, "Ar", json_object_new_double(params->ar_flow));
    json_object_object_add(root, "gases", gases);
    
    json_object_object_add(root, "temperature",
        json_object_new_double(params->chuck_temperature));
    
    FILE* fp = fopen(filename, "w");
    fprintf(fp, "%s\n", json_object_to_json_string_ext(root, JSON_C_TO_STRING_PRETTY));
    fclose(fp);
    
    json_object_put(root);
    printf("Recipe exported to %s\n", filename);
}

ProcessParams import_recipe_json(const char* filename) {
    ProcessParams params = {0};
    
    FILE* fp = fopen(filename, "r");
    if (!fp) {
        printf("Error opening file %s\n", filename);
        return params;
    }
    
    fseek(fp, 0, SEEK_END);
    long fsize = ftell(fp);
    fseek(fp, 0, SEEK_SET);
    
    char* json_str = malloc(fsize + 1);
    fread(json_str, 1, fsize, fp);
    json_str[fsize] = 0;
    fclose(fp);
    
    json_object* root = json_tokener_parse(json_str);
    
    json_object* obj;
    if (json_object_object_get_ex(root, "pressure", &obj))
        params.pressure = json_object_get_double(obj);
    if (json_object_object_get_ex(root, "source_power", &obj))
        params.source_power = json_object_get_double(obj);
    if (json_object_object_get_ex(root, "bias_power", &obj))
        params.bias_power = json_object_get_double(obj);
    
    json_object* gases;
    if (json_object_object_get_ex(root, "gases", &gases)) {
        if (json_object_object_get_ex(gases, "CHF3", &obj))
            params.chf3_flow = json_object_get_double(obj);
        if (json_object_object_get_ex(gases, "CF4", &obj))
            params.cf4_flow = json_object_get_double(obj);
        if (json_object_object_get_ex(gases, "Ar", &obj))
            params.ar_flow = json_object_get_double(obj);
    }
    
    json_object_put(root);
    free(json_str);
    
    printf("Recipe imported from %s\n", filename);
    return params;
}

void recipe_portability_example() {
    // Create recipe
    ProcessParams oxide_etch = {
        .pressure = 15.0,
        .source_power = 1200.0,
        .bias_power = 180.0,
        .chf3_flow = 40.0,
        .cf4_flow = 10.0,
        .ar_flow = 300.0,
        .chuck_temperature = 20.0
    };
    
    // Export to JSON
    export_recipe_json(&oxide_etch, "oxide_etch.json");
    
    // Export to XML
    export_recipe_xml(&oxide_etch, "oxide_etch.xml");
    
    // Export to equipment-specific format
    export_recipe_lam(&oxide_etch, "oxide_etch.lam");
    
    // Import and verify
    ProcessParams imported = import_recipe_json("oxide_etch.json");
    
    printf("\nVerifying import:\n");
    printf("  Pressure: %.1f mTorr\n", imported.pressure);
    printf("  Source power: %.0f W\n", imported.source_power);
    printf("  Bias power: %.0f W\n", imported.bias_power);
}

Example 15: Pulsed Plasma Control C

Implement pulsed plasma for reduced damage and improved selectivity.

#include "plasmaetch.h"

void pulsed_plasma_example(PlasmaReactor* reactor) {
    printf("=== Pulsed Plasma Etching ===\n\n");
    
    // Pulsing parameters
    PulseConfig pulse = {
        .frequency = 1000.0,        // Hz
        .duty_cycle = 0.50,         // 50% on-time
        .power_on = 1500.0,         // W
        .power_off = 0.0,           // W (complete off)
        .bias_on = 200.0,           // W
        .bias_off = 0.0             // W
    };
    
    double pulse_period = 1.0 / pulse.frequency;  // seconds
    double on_time = pulse_period * pulse.duty_cycle;
    double off_time = pulse_period * (1.0 - pulse.duty_cycle);
    
    printf("Pulse Configuration:\n");
    printf("  Frequency: %.0f Hz\n", pulse.frequency);
    printf("  Duty cycle: %.0f%%\n", pulse.duty_cycle * 100);
    printf("  On-time: %.3f ms\n", on_time * 1000);
    printf("  Off-time: %.3f ms\n\n", off_time * 1000);
    
    // Setup base process
    ProcessParams base_params = {
        .pressure = 15.0,
        .chf3_flow = 40.0,
        .ar_flow = 300.0,
        .chuck_temperature = 20.0
    };
    
    setProcessParameters(reactor, base_params);
    setGasFlows(reactor, createGasMix(GAS_CHF3, 40.0, GAS_AR, 300.0));
    
    // Run pulsed etch
    int num_pulses = 1000;  // ~1 second for 1kHz
    double total_etch_time = num_pulses / pulse.frequency;
    
    printf("Running pulsed etch (%d pulses, %.1f s)...\n", 
           num_pulses, total_etch_time);
    
    for (int i = 0; i < num_pulses; i++) {
        // ON phase
        setRFPower(&reactor->source_rf, pulse.power_on);
        setRFPower(&reactor->bias_rf, pulse.bias_on);
        delay(on_time);
        
        // OFF phase
        setRFPower(&reactor->source_rf, pulse.power_off);
        setRFPower(&reactor->bias_rf, pulse.bias_off);
        delay(off_time);
        
        if ((i + 1) % 100 == 0) {
            printf("  Pulse %d/%d\r", i + 1, num_pulses);
            fflush(stdout);
        }
    }
    
    printf("\n\nPulsed etch complete\n");
    printf("Time-averaged power: %.0f W\n", pulse.power_on * pulse.duty_cycle);
    printf("Benefits: Reduced damage, improved selectivity, better CD control\n");
}

Example 16: Cryogenic Etching C

Cryogenic silicon etching for ultra-high aspect ratios.

void cryogenic_etch_example(PlasmaReactor* reactor) {
    printf("=== Cryogenic Silicon Etching ===\n\n");
    
    // Cryogenic parameters
    ProcessParams cryo_params = {
        .pressure = 5.0,            // Low pressure
        .source_power = 1800.0,     // High plasma density
        .bias_power = 20.0,         // Low ion energy
        .sf6_flow = 80.0,           // Etchant
        .o2_flow = 20.0,            // Passivation control
        .chuck_temperature = -120.0 // Cryogenic cooling
    };
    
    printf("Process Conditions:\n");
    printf("  Temperature: %.0f C\n", cryo_params.chuck_temperature);
    printf("  Pressure: %.1f mTorr\n", cryo_params.pressure);
    printf("  SF6/O2: %.0f/%.0f sccm\n", cryo_params.sf6_flow, cryo_params.o2_flow);
    printf("\n");
    
    // Cool down chuck
    printf("Cooling chuck to %.0f C...\n", cryo_params.chuck_temperature);
    setChuckTemperature(reactor, cryo_params.chuck_temperature);
    
    while (getChuckTemperature(reactor) > cryo_params.chuck_temperature + 5.0) {
        double current_temp = getChuckTemperature(reactor);
        printf("  Current temp: %.1f C\r", current_temp);
        fflush(stdout);
        delay(1.0);
    }
    printf("\nTarget temperature reached\n\n");
    
    // Load wafer and allow thermal equilibration
    printf("Loading wafer and stabilizing...\n");
    Substrate wafer = createSiliconWafer(300.0);
    loadWafer(reactor, &wafer);
    delay(60.0);  // 1 minute thermal equilibration
    
    // Set process conditions
    setProcessParameters(reactor, cryo_params);
    setGasFlows(reactor, createGasMix(GAS_SF6, 80.0, GAS_O2, 20.0));
    
    // Etch
    printf("Starting cryogenic etch...\n");
    ignitePlasma(reactor, 1000.0, 3.0);
    
    EtchResult result = runEtchProcess(reactor, &wafer, 300.0);  // 5 minutes
    
    printf("\n=== Results ===\n");
    printf("Etch depth: %.1f um\n", result.depth);
    printf("Etch rate: %.1f um/min\n", result.etch_rate / 1000.0);
    printf("Profile angle: %.1f degrees\n", result.profile.sidewall_angle);
    printf("Aspect ratio: %.1f:1\n", result.aspect_ratio);
    printf("Surface roughness: %.2f nm RMS\n", result.roughness);
    
    // Warm up
    printf("\nWarming chuck...\n");
    setChuckTemperature(reactor, 20.0);
    delay(120.0);
    unloadWafer(reactor);
}

Example 17: Atomic Layer Etching C

Self-limiting ALE for atomic-scale precision.

void ale_process_example(PlasmaReactor* reactor) {
    printf("=== Atomic Layer Etching (ALE) ===\n\n");
    
    // ALE parameters
    ALERecipe ale = {
        // Modification step (Cl adsorption)
        .mod_step = {
            .gas = GAS_CL2,
            .flow = 50.0,
            .pressure = 10.0,
            .temperature = 20.0,
            .plasma_power = 300.0,  // Low power
            .duration = 5.0         // Saturation time
        },
        
        // Removal step (Ar+ sputtering)
        .removal_step = {
            .gas = GAS_AR,
            .flow = 100.0,
            .pressure = 5.0,
            .bias_power = 50.0,     // Low energy ions
            .duration = 3.0
        },
        
        .target_depth = 50.0,       // nm
        .etch_per_cycle = 0.3       // nm/cycle
    };
    
    int num_cycles = (int)(ale.target_depth / ale.etch_per_cycle);
    
    printf("ALE Configuration:\n");
    printf("  Modification: Cl2 plasma, %.0f s\n", ale.mod_step.duration);
    printf("  Removal: Ar+ ions, %.0f s\n", ale.removal_step.duration);
    printf("  Etch per cycle: %.2f nm\n", ale.etch_per_cycle);
    printf("  Target depth: %.1f nm\n", ale.target_depth);
    printf("  Cycles required: %d\n\n", num_cycles);
    
    // Execute ALE cycles
    double total_depth = 0.0;
    
    for (int cycle = 0; cycle < num_cycles; cycle++) {
        // Modification step
        setProcessParameters(reactor, &ale.mod_step);
        setGasFlows(reactor, createGasMix(GAS_CL2, 50.0));
        ignitePlasma(reactor, 200.0, 1.0);
        delay(ale.mod_step.duration);
        stopPlasma(reactor);
        
        // Purge
        stopGasFlows(reactor);
        delay(1.0);
        
        // Removal step
        setProcessParameters(reactor, &ale.removal_step);
        setGasFlows(reactor, createGasMix(GAS_AR, 100.0));
        ignitePlasma(reactor, 100.0, 1.0);
        delay(ale.removal_step.duration);
        stopPlasma(reactor);
        
        // Purge
        stopGasFlows(reactor);
        delay(1.0);
        
        total_depth += ale.etch_per_cycle;
        
        if ((cycle + 1) % 10 == 0) {
            printf("Cycle %3d/%d | Depth: %.1f nm\n", 
                   cycle + 1, num_cycles, total_depth);
        }
    }
    
    printf("\n=== ALE Complete ===\n");
    printf("Total cycles: %d\n", num_cycles);
    printf("Final depth: %.1f nm\n", total_depth);
    printf("Depth precision: ±%.2f nm\n", ale.etch_per_cycle * 0.1);
}

Example 18: Machine Learning Optimization Python

Use ML to optimize process parameters.

import plasmaetch as pe
import numpy as np
from sklearn.neural_network import MLPRegressor
from sklearn.preprocessing import StandardScaler

# Collect training data from DOE
X_train = []  # Input features: [power, pressure, bias, flows]
y_train = []  # Output targets: [rate, uniformity, selectivity]

# Load historical process data
data = pe.load_process_database("process_history.db")

for record in data:
    X_train.append([
        record['source_power'],
        record['bias_power'],
        record['pressure'],
        record['chf3_flow'],
        record['ar_flow']
    ])
    
    y_train.append([
        record['etch_rate'],
        record['uniformity'],
        record['selectivity']
    ])

X_train = np.array(X_train)
y_train = np.array(y_train)

print(f"Training data: {len(X_train)} samples\n")

# Normalize data
scaler_X = StandardScaler()
scaler_y = StandardScaler()

X_scaled = scaler_X.fit_transform(X_train)
y_scaled = scaler_y.fit_transform(y_train)

# Train neural network
model = MLPRegressor(
    hidden_layer_sizes=(20, 20, 10),
    activation='relu',
    max_iter=2000,
    random_state=42
)

print("Training neural network...")
model.fit(X_scaled, y_scaled)
print(f"Training score: {model.score(X_scaled, y_scaled):.3f}\n")

# Optimization function
def objective(params):
    # Predict outcomes
    X_pred = scaler_X.transform([params])
    y_pred = scaler_y.inverse_transform(model.predict(X_pred))[0]
    
    # Multi-objective: maximize rate, minimize uniformity variation
    rate_score = -(y_pred[0] - 250.0)**2  # Target 250 nm/min
    unif_score = -(y_pred[1] - 2.0)**2    # Target 2% uniformity
    sel_score = -(y_pred[2] - 20.0)**2    # Target 20:1 selectivity
    
    return rate_score + unif_score + sel_score

# Optimize
from scipy.optimize import differential_evolution

bounds = [
    (1000, 1500),  # source_power
    (100, 300),    # bias_power
    (10, 30),      # pressure
    (30, 50),      # chf3_flow
    (200, 400)     # ar_flow
]

print("Optimizing process parameters...")
result = differential_evolution(objective, bounds, maxiter=100)

optimized_params = result.x
print("\nOptimized Parameters:")
print(f"  Source power: {optimized_params[0]:.0f} W")
print(f"  Bias power: {optimized_params[1]:.0f} W")
print(f"  Pressure: {optimized_params[2]:.1f} mTorr")
print(f"  CHF3 flow: {optimized_params[3]:.0f} sccm")
print(f"  Ar flow: {optimized_params[4]:.0f} sccm")

# Predict performance
X_opt = scaler_X.transform([optimized_params])
y_opt = scaler_y.inverse_transform(model.predict(X_opt))[0]

print("\nPredicted Performance:")
print(f"  Etch rate: {y_opt[0]:.1f} nm/min")
print(f"  Uniformity: {y_opt[1]:.2f}%")
print(f"  Selectivity: {y_opt[2]:.1f}:1")

Example 19: Fault Detection System C

Real-time fault detection and classification.

#include "plasmaetch.h"

typedef enum {
    FAULT_NONE,
    FAULT_PLASMA_UNSTABLE,
    FAULT_PRESSURE_DRIFT,
    FAULT_REFLECTED_POWER,
    FAULT_GAS_FLOW,
    FAULT_ENDPOINT_TIMEOUT
} FaultType;

typedef struct {
    FaultType type;
    double severity;        // 0-1
    char* description;
    char* recommendation;
} FaultEvent;

FaultEvent detect_faults(PlasmaReactor* reactor, ProcessParams* target) {
    FaultEvent fault = {FAULT_NONE, 0.0, "No fault", "Continue"};
    
    // Check plasma stability
    PlasmaState plasma = getPlasmaState(reactor);
    double vpp_variation = plasma.vpp_stddev / plasma.vpp_mean;
    
    if (vpp_variation > 0.10) {  // > 10% variation
        fault.type = FAULT_PLASMA_UNSTABLE;
        fault.severity = vpp_variation;
        fault.description = "Plasma Vpp unstable";
        fault.recommendation = "Check matching network, reduce power";
        return fault;
    }
    
    // Check pressure control
    double pressure = getPressure(&reactor->vacuum);
    double pressure_error = fabs(pressure - target->pressure) / target->pressure;
    
    if (pressure_error > 0.05) {  // > 5% error
        fault.type = FAULT_PRESSURE_DRIFT;
        fault.severity = pressure_error;
        fault.description = "Pressure out of spec";
        fault.recommendation = "Check throttle valve, verify pumping speed";
        return fault;
    }
    
    // Check reflected power
    double reflected = getReflectedPower(&reactor->source_rf);
    double forward = getForwardPower(&reactor->source_rf);
    double refl_percent = reflected / forward;
    
    if (refl_percent > 0.10) {  // > 10% reflected
        fault.type = FAULT_REFLECTED_POWER;
        fault.severity = refl_percent;
        fault.description = "High reflected power";
        fault.recommendation = "Retune matching network, check plasma";
        return fault;
    }
    
    // Check gas flows
    for (int i = 0; i < reactor->gases.num_lines; i++) {
        GasLine* line = &reactor->gases.lines[i];
        double setpoint = line->setpoint;
        double actual = line->actual_flow;
        double flow_error = fabs(actual - setpoint) / setpoint;
        
        if (flow_error > 0.03 && setpoint > 0) {  // > 3% error
            fault.type = FAULT_GAS_FLOW;
            fault.severity = flow_error;
            fault.description = "Gas flow error";
            fault.recommendation = "Check MFC calibration, verify supply pressure";
            return fault;
        }
    }
    
    return fault;
}

void fault_detection_example(PlasmaReactor* reactor) {
    printf("=== Fault Detection System ===\n\n");
    
    ProcessParams target = {
        .pressure = 15.0,
        .source_power = 1200.0,
        .bias_power = 180.0,
        .chf3_flow = 40.0,
        .ar_flow = 300.0
    };
    
    setProcessParameters(reactor, target);
    ignitePlasma(reactor, 1000.0, 3.0);
    
    printf("Monitoring process (60 seconds)...\n\n");
    
    for (int t = 0; t < 600; t++) {  // 60 seconds
        delay(0.1);
        
        FaultEvent fault = detect_faults(reactor, &target);
        
        if (fault.type != FAULT_NONE) {
            printf("\n*** FAULT DETECTED ***\n");
            printf("Type: %s\n", fault.description);
            printf("Severity: %.1f%%\n", fault.severity * 100);
            printf("Recommendation: %s\n", fault.recommendation);
            
            if (fault.severity > 0.20) {  // Critical fault
                printf("\nCRITICAL FAULT - Stopping process\n");
                stopPlasma(reactor);
                return;
            }
        }
        
        if (t % 10 == 0) {
            printf("Time: %3ds | Status: %s\r", 
                   t / 10, 
                   fault.type == FAULT_NONE ? "OK" : "WARNING");
            fflush(stdout);
        }
    }
    
    printf("\n\nMonitoring complete - no critical faults\n");
}

Example 20: Complete Production Workflow C

End-to-end production workflow with all features integrated.

#include "plasmaetch.h"

int production_workflow(PlasmaReactor* reactor, ProductionLot* lot) {
    printf("=== Production Workflow ===\n");
    printf("Lot ID: %s\n", lot->lot_id);
    printf("Wafers: %d\n", lot->num_wafers);
    printf("Recipe: %s\n\n", lot->recipe_name);
    
    // 1. Chamber qualification
    printf("Step 1: Chamber Qualification\n");
    QualificationResult qual = qualifyReactor(reactor);
    if (!qual.passed) {
        printf("  FAILED - Chamber not qualified\n");
        return -1;
    }
    printf("  PASSED\n\n");
    
    // 2. Recipe load
    printf("Step 2: Loading Recipe\n");
    ProcessParams recipe = loadRecipe(lot->recipe_name);
    setProcessParameters(reactor, recipe);
    printf("  Recipe loaded: %s\n\n", lot->recipe_name);
    
    // 3. Seasoning
    printf("Step 3: Chamber Seasoning\n");
    runSeasoningWafer(reactor);
    printf("  Seasoning complete\n\n");
    
    // 4. Process wafers
    printf("Step 4: Processing Wafers\n");
    time_t start_time = time(NULL);
    
    for (int i = 0; i < lot->num_wafers; i++) {
        printf("  Wafer %d/%d...\n", i + 1, lot->num_wafers);
        
        // Load
        loadWafer(reactor, &lot->wafers[i]);
        
        // Process with monitoring
        EtchResult result = runEtchProcessWithMonitoring(
            reactor, 
            &lot->wafers[i], 
            &recipe
        );
        
        // Check specs
        if (!meetsSpecifications(&result, &lot->spec)) {
            printf("    WARNING: Out of spec\n");
            lot->wafers[i].status = WAFER_FAIL;
        } else {
            lot->wafers[i].status = WAFER_PASS;
        }
        
        // Log
        logWaferResult(&lot->wafers[i], &result);
        
        // Unload
        unloadWafer(reactor);
        
        // SPC check every 25 wafers
        if ((i + 1) % 25 == 0) {
            SPCStatus spc = checkSPCLimits(lot);
            if (!spc.in_control) {
                printf("  SPC OUT OF CONTROL - Stopping lot\n");
                return -1;
            }
        }
    }
    
    time_t end_time = time(NULL);
    
    // 5. Post-process chamber clean
    printf("\nStep 5: Chamber Clean\n");
    runChamberClean(reactor);
    printf("  Clean complete\n\n");
    
    // 6. Generate reports
    printf("Step 6: Generating Reports\n");
    generateLotReport(lot, "lot_report.pdf");
    printf("  Report saved\n\n");
    
    // Summary
    int passed = 0, failed = 0;
    for (int i = 0; i < lot->num_wafers; i++) {
        if (lot->wafers[i].status == WAFER_PASS) passed++;
        else failed++;
    }
    
    double yield = (double)passed / lot->num_wafers * 100.0;
    double throughput = (double)lot->num_wafers / ((end_time - start_time) / 3600.0);
    
    printf("=== Lot Summary ===\n");
    printf("Lot ID: %s\n", lot->lot_id);
    printf("Wafers processed: %d\n", lot->num_wafers);
    printf("Passed: %d\n", passed);
    printf("Failed: %d\n", failed);
    printf("Yield: %.1f%%\n", yield);
    printf("Throughput: %.1f wph\n", throughput);
    printf("Process time: %ld seconds\n", end_time - start_time);
    
    return 0;
}

Production Workflow Features:

  • Automated chamber qualification before processing
  • Recipe management and versioning
  • Chamber seasoning for repeatability
  • Real-time SPC monitoring
  • Automated fault detection and handling
  • Comprehensive data logging
  • Automated reporting
  • Yield and throughput tracking