RF Matching Network Description Energy for creating the

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 (AMC 1). 1

AMC 1 Module Electrical Select (Not Used) IN Socket (Not Used) OUT Socket (Not Used) Magnitude/Phase Detector Matching Unit Control 2

AMC 1 Module Power Supply Eprom Secondary Address Switch Fuses and Test Points Programmable IC Serial Coms Chips Links 3

ICP AMC 1 Module Control Coil AMC 1 Tune P M M P Balun Type RF Matching Unit Tune Load Tune PFC Master Load MU Control Magnitude and Phase Detector Mag/Phase Input RF Generator Interlocks OK 4

AMC Module Switch Settings Page 24 AMC Platen SW 1 1 2 3 4 Master On On Link 1 In for Vacuum Type Out for Air Type Link 2 In for Vacuum Type Out for Air Type SW 1 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 7 AMC Coil Secondary Address 6 5

AMC 1 Module Control AMC 1 Tune P M M P ELECTRODE Tune Load RF Matching Unit PFC Master Load MU Control Mag/Phase Input Magnitude and Phase Detector RF Generator Interlocks OK 6

Magnitude and Phase Detector • The servo loop consists of power op amps IC 3 and IC 4 for driving the Tune and Load capacitor drive motors, error amplifiers consisting of IC 12 (output pins 1 for the load and pin 8 for the Tune), and two loop gain amplifiers of IC 5. • The feedback position of the Load and Tune capacitors are converted to digital data by an A to D convertor IC 16 for metering by turning on the appropriate switch of IC 10 (pin 16 for Load and pin 9 for Tune 7

0 v +24 v Coolant 1 1. DI Meter 2. Flow Switch Gate Closed Magnetic Reed Switch Gate Closed 0 v RL 2 ICP RF Interlocks RL 1 Coolant 2 Clamp On 1. Heated Lid Temperature Controller Magnetic Reed Switch RF Enclosure 2 Micro - Switches He Backside Cooling Platen Matching Unit Top Matching Unit HBC Module Trip Points 2 Micro-Switches 1 Micro - Switch He Cool Bottom Mu Top Mu Interlock ok RL 3 8

Serial Communications +24 V Supply Wiring Module PSU Serial Chips Computer Coms Card Computer Failure 9

ICP Process Sequence Standby Process Etch Process Chamber Gas Preparation Stabilization Matching Unit Capacitors go to their start position Process Gases Switch On APC Goes to position Pumps to Base Process Timer Finished Process Timer Starts Process Timer Stops RF Switches On RF Switches Off Gases Running Gases Off Process pressure Stabilize Pumps to Base Vac Pressure PFC Gases Control PFC Gases Off Vac Hi Vac OPN Vac APC PFC RF on PFC RF Off PFC Timer Finished EPD Waiting for End Point EPD End Point Achieved AMC Drive Caps 10