Method and apparatus for photomask plasma etching

An apparatus for plasma etching, comprising:

• a process chamber;
• a substrate support pedestal disposed in the process chamber and having an opening adapted to receive a photomask reticle;
• an RF power source;
• an antenna comprising a co-axial coil positioned to inductively couple power from the RF power source to a plasma within the process chamber;
• and
• an ion-radical shield for controlling the spatial distribution of charged and neutral species of the plasma, wherein said ion-radical shield further comprises:
• a substantially flat member having an areal extent larger than an areal extent of the substrate support pedestal;
• a plurality of apertures formed through the member and configured to promote center fast etching;
• and
• a plurality of legs secured to the member above the substrate support pedestal, wherein the legs do not extend beyond the areal extent of the member.

An apparatus for plasma etching, comprising:

• a process chamber having a conductive body and a dielectric ceiling;
• a substrate support pedestal disposed in the process chamber, the substrate support having a reticle adapter with an opening substantially centered with respect to the pedestal;
• an RF power source;
• a co-axial antenna positioned to inductively couple power from the RF power source to a plasma within the process chamber;
• and
• an ion-radical shield disposed in the chamber above the pedestal and comprising a plurality of apertures adapted to control the spatial distribution of charged and neutral species of the plasma;
• wherein the ion-radical shield has an areal extent larger than an areal extent of the substrate support pedestal, wherein a plurality of legs are secured to the ion-radical shield and support the ion-radical shield a distance of about 1.5 inches (3.81 cm) to about 4 inches (10.16 cm) above the pedestal.

An apparatus for plasma etching, comprising:

• an inductively coupled plasma process chamber;
• a substrate support pedestal disposed in the process chamber, the substrate support comprising a cathode and a reticle adapter covering an upper surface of the cathode having a top portion with an opening to receive a photomask reticle;
• an RF power source for forming a plasma within the chamber;
• an ion-radical shield disposed in the chamber above the pedestal and comprising a plurality of apertures arranged in a square grid pattern for controlling a spatial distribution of charged and neutral species of the plasma, wherein the ion-radical shield is fabricated from anodized aluminum and has an areal extent larger than an areal extent of the photomask reticle;
• a plurality of legs extending from the substrate support pedestal and secured to the ion-radical shield, wherein the legs do not extend beyond the areal extent of the ion-radical shield, wherein the ion-radical shield has a height relative to the pedestal that controls etch rate during plasma processing and the height is set by the legs utilized to support the ion-radical shield above the pedestal, wherein the height is between about 1.5 inches (3.81 cm) to about 4 inches (10.16 cm) in a process chamber having a distance of about 6 inches between the pedestal and a ceiling of the process chamber;
• and
• an edge ring disposed on the reticle adapter and having the plurality of legs extending therefrom.