Determination of etching parameters for pulsed xenon difluoride (xef2) etching of silicon using chamber pressure data

A method for determining etching parameters for pulsed xenon difluoride (XeF2) etching of a solid silicon surface, the method comprising:

• measuring a first pressure inside of an evacuated vacuum chamber containing a sample comprising the solid silicon surface prior to initializing an etch of the silicon surface;
• repeatedly exposing the silicon surface to pulses of XeF2 vapor;
• chemically reacting the silicon surface with the XeF2 vapor to generate at least two different gaseous species of silicon fluoride;
• subsequent to chemically reacting the silicon surface with the XeF2 vapor, measuring a second pressure inside of the vacuum chamber pressure, wherein the second pressure is higher than the first pressure;
• calculating at least one of a depletion of the XeF2, a depth of an etch within the silicon surface, a volume of the solid surface that is etched by the etching gas, a volumetric etching rate of the solid surface by the etching gas, and a thickness etching rate of the silicon surface by the etching gas, wherein the calculation comprises the use of the difference between the first pressure and the second pressure.

A pulsed etching system for determining etching parameters for pulsed xenon difluoride (XeF2) etching of a solid silicon surface, comprising:

• a source chamber;
• an expansion chamber in fluid communication with the source chamber;
• a first valve configured to selectively separate the source chamber from the expansion chamber;
• an etch chamber in fluid communication with the source chamber;
• a second valve configured to selectively separate the etch chamber from the expansion chamber;
• and
• a pump in fluid communication with the source chamber, the expansion chamber, and the etch chamber, wherein the pump is configured to equalize pressure within source chamber, the expansion chamber, and the etch chamber.