Selective etch using material modification and RF pulsing
Semiconductor systems and methods may include methods of performing selective etches that include modifying a material on a semiconductor substrate. The substrate may have at least two exposed materials on a surface of the semiconductor substrate. The methods may include forming a low-power plasma within a processing chamber housing the semiconductor substrate. The low-power plasma may be a radio-frequency (“RF”) plasma, which may be at least partially formed by an RF bias power operating between about 10 W and about 100 W in embodiments. The RF bias power may also be pulsed at a frequency below about 5,000 Hz. The methods may also include etching one of the at least two exposed materials on the surface of the semiconductor substrate at a higher etch rate than a second of the at least two exposed materials on the surface of the semiconductor substrate.
1. A substrate processing chamber comprising:
a pedestal configured to support a semiconductor substrate comprising a bipolar electrostatic chuck;
an RF bias power electrically coupled with the pedestal and configured to operate as a plasma-generating electrode to generate a plasma within the substrate processing chamber at a power of between about 20 W and about 50 W, wherein the RF bias power is a pulsing power configured to pulse at a frequency below about 5,000 Hz; and
a DC pulsing power supply electrically coupled with the substrate processing chamber, wherein the DC pulsing power supply is configured to be pulsed on for a duration of 100 microseconds or less at a duty cycle of less than about 50%, and the DC pulsing power supply is applied to an electrical ground of the bipolar electrostatic chuck.
2. The substrate processing chamber of claim 1 , wherein the DC pulsing power supply is configured to pulse at a frequency to produce priming particles without developing a plasma sheath.
3. The substrate processing chamber of claim 1 , wherein the RF bias power is operated at a pulsing frequency greater than or about 500 Hz.
4. The substrate processing chamber of claim 1 , wherein the DC pulsing power supply is configured to operate on an alternating frequency with the RF bias power.
5. A substrate processing chamber comprising:
a pedestal configured to support a semiconductor substrate;
an RF bias power electrically coupled with the pedestal and configured to operate as a plasma-generating electrode to generate a plasma within the substrate processing chamber, wherein the RF bias power is a pulsing power configured to pulse at a frequency below about 5,000 Hz at a duty cycle of between about 20% and about 50%; and
a DC pulsing power supply electrically coupled with the substrate processing chamber, wherein the DC pulsing power supply is configured to be pulsed on for a duration of 100 microseconds or less at a duty cycle of less than about 50%, and the DC pulsing power supply is configured to operate on an alternating frequency with the RF bias power.
6. The substrate processing chamber of claim 5 , wherein the DC pulsing power supply is configured to pulse at a frequency to produce priming particles without developing a plasma sheath.
7. The substrate processing chamber of claim 5 , wherein the pedestal comprises a bipolar electrostatic chuck, and wherein the DC pulsing power supply is applied to an electrical ground of the bipolar electrostatic chuck.
8. The substrate processing chamber of claim 5 , wherein the RF bias power is operated at a pulsing frequency greater than or about 500 Hz.
9. The substrate processing chamber of claim 5 , wherein the RF bias power is configured to operate at greater than or about 20 W.
10. The substrate processing chamber of claim 5 , wherein the RF bias power is configured to operate at less than or about 50 W.