How To Make A Plasma Control System

Transcription

1 XXII. Erfahrungsaustausch Mühlleiten 2015 Plasmaanalyse und Prozessoptimierung mittels spektroskopischem Plasmamonitoring in industriellen Anwendungen Swen Marke,, Lichtenau Thomas Schütte, Plasus GmbH, Kissing 1

2 Products Emission spectrometer NIR sensor Ultrasonic analysis 2

3 Emission Spectroscopy excitation by electron collision E excitation =E up -E 0 de-excitation by spontaneous emission E hn =E up -E low 3

4 Low Temperature Plasma Free Ions Free Neutrals Free Electrons Quasi-Neutrality Thermal Non Equilibrium Hot Electrons Cold Ions and Neutral Interaction with Substrate Deposition, Etching, Surface Modification 4

5 Intensity [a. u.] Spectroscopic Plasma Monitoring Information included in line emission 1,0 0,8 I max Intensity: - plasma parameters - density of neutrals, ions and electrons 0,6 0,4 0,2 Full Width Half Maximum FWHM: - apparatus profile: system configuration - line profile: broadening mechanism e.g. Doppler broadening (particle temperature) 0, Wavelength [nm] Wavelength 0 : - element, species 0 5

6 Spectroscopic Plasma Monitoring Real-time observation of line intensities I( t) ~ n X ( Te ) n( t) e Features: - real time observation of n - monitoring of different species Spectrometer: - wavelength calibrated - no intensity calibration 6

7 EMICON SA Series Stand-alone system Operating system: Integrated processor and display with EMICON SA firmware Number of spectrometer channels: 1-8 Spectral range of each channel: approx. 1.5 nm Number of analog channels: 2-8 for external inputs 2-8 for external outputs Signal resolution: 16 Bit Interfaces for system integration: Profibus and LAN, DIOs 7

8 EMICON Systems Field of Applications Production: - Real-time plasma emission monitoring - Evaluation of plasma process - Control of process parameters - Endpoint detection - Fault detection - PID control of gas flow and/or power R&D: - Basic R&D tasks - Measurement of plasma parameters - Analysis of molecular radiation - Development of prototype applications - Design new plasma control techniques 8

9 Applications - Film deposition and coating - PECVD - System diagnostics - Fault detection - Plasma etching and endpoint control - EPD - Large area coating - MW application for foil coating - ATM plasma processes - Process control of plasma jets - Uniformity control of plasma flame application - Sputtering processes - PID - control of reactive sputtering processes - HiPIMS / HPPMS application - Solar cell production - CIGS cells - AR coating - PIN structure of a-si:h cells 9

10 Plasma homogeneity control of large area applications Process optimization of MW source for foil coating gas shower for Ar and O LAMPS system Gas shower for HMDSO Application: - Evaluation of 2D plasma homogeneity - Optimization of gas inlet positions for process gases (e.g. HMDSO/Ar/O 2 ) - Monitoring of local impurities/inhomogeneity (e.g. from substrate) - Recording of transient effects and long term stability 10

11 Process optimization by plasma monitoring Large area MW source Kanal 1: oben Kanal 2: oben mittig Features: - Monitoring of all spectroscopic channel in real time - Concurrent monitoring of monitor tracks from all channels Kanal 3: Mitte Kanal 4: unten mittig Benefit: Instant identification of: - transient effects - long term drifts - process stability - inhomogeneity 11

12 Signal [a.u.] Process optimization by plasma monitoring Large area MW source Line intensities of line-of-sights OH 309 nm (v) OH 309 nm (h) O 777 nm (v) O 777 nm (h) H 486 nm (v) H 486 nm (h) CH 431 nm (v) Evaluation features: - vertical and horizontal dependencies 8000 CH 431 nm (h) Si 288 nm (v) Si 288 nm (h) - Profile measurements for all plasma species Non-uniform gas input Ar of O 2 in cover plate? - Localization of Inhomogeneity - Real spatial resolution 2000 v: top h: right v: top centered h: right centered 50 v: center h: center 0 Position of line-of-sight [mm] vertical (v) / horizontal (h) -50 v: bottom centered h: left centered -100 v: bottom h: left

13 Process Control of Precursor Flow Control of HMDSO flow in ATM plasma jets Application: - Plasma jets with precursor HMDSO - Control of HMDSO flow using Si line intensity - Single and multiple plasma jet setups In cooperation with: 13

14 Intensity of metal line Reactive Sputtering Processes PID process control gases Ar, O 2 magnetron metal target plasma compound thin film substrate Si SiO x Ar, O, Si Si, SiO x SiO x glass No O 2 flow: - Sputtering by Ar - No film production - High signal from metal line (Si) High O 2 flow: - Target covered by oxygen (poisoned) - Low film production - Low signal from metal line (Si) Hysteresis curve: Controlled O 2 flow: - Effective sputtering by oxygen - High film production - Desired stoichiometric ratio (SiO x ) Control of O 2 flow ensures desired film production Intensity of metal line controls O 2 gas flow Reactive gas flow 14

15 Reactive Sputtering Processes PID process control Application: - Roll-to-roll (RTR) coater - SiO 2 reactive sputtering - PID control of O 2 gas flow Other applications: - Touch panel: TCO - Architectural glass: LowE coating - Decorative coatings: e.g. Al - E-Paper: TCO and Al/Cu 15

16 Reactive Sputtering Processes EMICON Multi-Channel setup 16

17 Reactive Sputtering Processes PID process control Closed-loop control of gas flow 100% 60% 60% 60% 100% Features: Determination of best PID parameters: - Fast response - Small overshoot - No oscillation - Long-term stability K p = 0.2 K i = 120 Ti = % K p = 0.2 K i = 200 T i = % K p = 0.2 K i = 200 Ti = % K p = 0.2 K i = 120 T i = 800 K p = 0.2 K i = 200 T i = 800 K p = 0.2 K i = 200 T i = 400 0% 17

18 Summary EMICON SA System Spectral broad-band monitoring: Multi-channel setup: Replay mode: Set-point functions: Advanced PID control: Recipe manager: Remote control interfaces: Advanced plasma process analysis Process control of multiple gases / target materials All time information on chamber status Multi-process chamber application Spatial resolution for large area plasmas Offline analysis of recorded process data Design and test of process recipes End-point detection Quality control Reactive magnetron sputtering Gas flow and/or power control Multi-process switching Multi-layer processes Industrial interfaces for system integration LAN API, Profibus, digital and analog I/Os, 18

19 Thank you for your attention! IfU Diagnostic Systems GmbH Gottfried-Schenker-Str Lichtenau diagnostic@ifu.de Firmengebäude der IfU 19