RF Matching Network Description Energy for creating the plasma in the STS systems is supplied by a radio frequency generator. The Process (plasma) chamber must be matched to the electrical impedance of the RF power transmission line. A mismatch would result in power being reflected into the source which would affect the plasma process. Matching is achieved by fitting an auto-matching unit between the Rf generator output and the plasma chamber. In order to continuously monitor the efficiency of matching between load and RF source, thus detecting if control adjustments are required, the first device in the RF line output from the generator is the reflectometer (Mag Phase unit). In order to measure the performance of the matching unit, its impedance as seen by the RF source must be determined. This is achieved by fitting a detector in the RF line between the RF generator and matching unit, in order to measure the magnitude and phase angle of the load impedance. The detector generates error correction signal as a result of a mismatch and this is passed to the automatic matching module (AMC1).

AMC1 Module       Electrical Select (Not Used)  IN Socket (Not Used)   OUT Socket (Not Used)   Matching Unit Control   Magnitude/Phase Detector  

AMC1 Module         Power Supply  Eprom  Secondary Address Switch    Fuses and Test Points  Programmable IC   Serial Coms Chips   Links 

ICP AMC1 Module Control Balun Type AMC1 RF Matching Unit P M M P Coil Tune Balun Type RF Matching Unit AMC1 P M Tune Load M P Tune PFC Master Load Magnitude and Phase Detector MU Control Mag/Phase Input RF Generator Interlocks OK

AMC Module Switch Settings Page 24 AMC Platen SW1 1 2 3 4 Master On On On On Link 1 In for Vacuum Type Out for Air Type Link 2 In for Vacuum Type Out for Air Type Secondary Address 7 AMC Coil SW1 1 2 3 4 Master Off On On On Link 1 In for Vacuum Type Out for Air Type Link 2 In for Vacuum Type Out for Air Type Secondary Address 6

AMC1 Module Control ELECTRODE AMC1 P M RF Matching Unit M P PFC Master Tune AMC1 P M Tune RF Matching Unit M Load P PFC Master Load MU Control Magnitude and Phase Detector Mag/Phase Input RF Generator Interlocks OK

Magnitude and Phase Detector The servo loop consists of power op amps IC3 and IC4 for driving the Tune and Load capacitor drive motors, error amplifiers consisting of IC12 (output pins 1 for the load and pin 8 for the Tune), and two loop gain amplifiers of IC5. The feedback position of the Load and Tune capacitors are converted to digital data by an A to D convertor IC16 for metering by turning on the appropriate switch of IC10 (pin 16 for Load and pin 9 for Tune

ICP RF Interlocks 0 v 0 v RL2 RL1 +24 v Coolant 1 Coolant 2 Clamp On RF Encl +24 v Coolant 1 1. DI Meter 2. Flow Switch Coolant 2 1. Heated Lid Temperature Controller Clamp On Magnetic Reed Switch RF Enclosure 2 Micro - Switches Gate Closed Magnetic Reed Switch He Backside Cooling HBC Module Trip Points Platen Matching Unit 2 Micro-Switches Top Matching Unit 1 Micro - Switch Gate Closed He Cool Bottom Mu Top Mu Interlock ok RL3

Serial Communications  +24V Supply  Wiring  Module PSU  Serial Chips  Computer Coms Card  Computer Failure

ICP Process Sequence Standby Process Etch Process Chamber Preparation Gas Stabilization Process Time Process Timer Finished Matching Unit Capacitors go to their start position Process Gases Switch On Process Timer Starts Process Timer Stops RF Switches On RF Switches Off APC Goes to position Gases Running Gases Off Pumps to Base Process pressure Stabilize Pumps to Base Vac Pressure Vac Hi Vac OPN AMC Drive Caps PFC Gases Vac APC PFC Gases Control PFC RF on PFC Timer EPD Waiting for End Point PFC Gases Off PFC RF Off PFC Timer Finished EPD End Point Achieved