Importance

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Abstract

A fluxmeter pneumatically measures the amount of plasma energy impinging onto a semiconductor wafer. The fluxmeter is comprised of two hollow bulbs filled with gas. One bulb has one end exposed to the plasma while the opposite base end is supported by a substantially constant temperature wafer chuck. The other bulb has one end exposed to a heater and the opposite base end supported by the chuck. The two bulbs are coupled to a differential pressure sensor, which output is coupled to a servo for controlling the current to the heater. When plasma energy is applied, gas pressure in the first bulb changes and is sensed by the pressure sensor. The servo then adjusts the heater current until the gas pressure in the second bulb equals that of the first bulb. Upon reaching equilibrium the heater current is measured to determine the plasma energy flux impinging on the wafer.

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First Claim