Removal of organic material from high aspect ratio structures
Embodiments of the disclosure include a method of device processing, comprising: exposing a device substrate to a carbon-free fluorine-containing gas for a first period of time, delivering an inert gas to the processing volume for a second period of time; and removing a organic fill material of the device substrate by generating a plasma over the device substrate, wherein the plasma comprises the inert gas. The device substrate comprises one or more layers disposed on the device substrate, wherein the one or more layers define at one or more high-aspect ratio (HAR) features, wherein the HAR feature includes sidewall surfaces and a bottom surface and the organic fill material disposed within the one or more HAR features.
1 . A method of forming a device, comprising:
exposing a device substrate to a carbon-free fluorine-containing gas for a first period of time, wherein the device substrate is disposed within a processing volume of a processing chamber, wherein the device substrate comprises:
one or more layers disposed on the device substrate, wherein the one or more layers define at least one high-aspect ratio (HAR) feature, wherein each HAR feature of the at least one HAR feature comprises sidewall surfaces and a bottom surface; and
an organic fill material disposed within the at least one HAR feature;
delivering an inert gas to the processing volume for a second period of time; and
removing the organic fill material by generating a plasma over the device substrate, wherein the plasma comprises the inert gas, wherein generating the plasma over the device substrate comprises:
delivering a radio frequency (RF) waveform according to an RF delivery period duty cycle, wherein the RF delivery period duty cycle comprises delivering the RF waveform for a third period of time and halting the delivery of the RF waveform for a fourth period of time; and
biasing the device substrate, wherein biasing the device substrate comprises delivering a pulsed voltage (PV) burst according to a PV burst delivery period duty cycle to an electrode disposed within the processing chamber, wherein the PV burst delivery period duty cycle comprises delivering the PV burst for a fifth period of time and halting the delivery of the PV burst for a sixth period of time wherein each PV burst comprises a plurality of voltage pulses that have respective on and off periods during a portion of the PV burst delivery period duty cycle, wherein the third period of time and the fifth period of time overlap in time.
2 . The method of claim 1 , wherein the device substrate further comprises a hardmask material that comprises a material selected from a group consisting of silicon nitride, silicon oxide, amorphous carbon, metals films, metal oxides, polymers, organosilicates, or combination thereof.
3 . The method of claim 1 , wherein the organic fill material comprises a photoresist or a backside antireflective coating (BARC).
4 . The method of claim 1 , wherein the carbon-free fluorine-containing gas comprises fluorine (F 2 ), hydrogen fluoride (HF), or deuterium fluoride (DF), or a combination of hydrogen (H 2 ) and nitrogen trifluoride (NF 3 ), or a combination of fluorine (F 2 ) and ammonia (NH 3 ).
5 . The method of claim 1 , wherein exposing the device substrate to the carbon-free fluorine-containing gas includes introducing the carbon-free fluorine-containing gas into the processing chamber at a rate between about 100 standard cubic-centimeters per minute (SCCM) to about 1000 SCCM.
6 . The method of claim 1 , wherein the first period of time is between about 1 second to about 3 minutes.
7 . The method of claim 1 , wherein the second period of time is between about 1 second to about 1 minute.
8 . The method of claim 1 , wherein the plasma essentially comprises the inert gas that includes argon, helium, xenon, or krypton.
9 . The method of claim 1 , wherein the PV burst further comprises:
a PV waveform, the PV waveform having a PV waveform duty cycle comprising delivering a first voltage for the fifth period of time to halting delivery of the first voltage for the sixth period of time.
10 . The method of claim 9 , wherein:
the RF delivery period duty cycle is about 50% to about 95%; and
the PV waveform duty cycle is about 10% to about 50%.
11 . The method of claim 9 , wherein:
the RF delivery period duty cycle is about 50% to about 95%.
12 . The method of claim 9 , wherein biasing the device substrate comprises delivering the RF waveform to the electrode disposed within the processing chamber.
13 . The method of claim 9 , wherein the first voltage is between about −50 V and −2000 V.
14 . The method of claim 9 , further comprising maintaining the device substrate at a cryogenic temperature.
15 . A method of device processing, comprising:
exposing a device substrate to a carbon-free fluorine-containing gas for a configurable exposure period, wherein:
the carbon-free fluorine-containing gas comprises fluorine,
the device substrate is disposed within a processing volume of a processing chamber, and
one or more layers disposed on the device substrate define at least one high-aspect ratio (HAR) feature, wherein each HAR feature of the at least one HAR feature comprises sidewall surfaces and a bottom surface and an organic fill material disposed within the at least one HAR feature;
delivering an inert gas to the processing volume for a configurable purge period; and
removing the organic fill material, wherein removing the organic fill material comprises a plasma-assisted etching process, wherein the plasma-assisted etching process comprises:
delivering an inert gas to the processing volume of the processing chamber;
delivering a radio frequency (RF) waveform from a waveform generator coupled to an inductively coupled plasma assembly according to an RF delivery period duty cycle, wherein the RF delivery period duty cycle comprises delivering the RF waveform for a first period of time and halting delivery of the RF waveform for a second period of time;
biasing the device substrate, wherein biasing the device substrate comprises delivering a pulsed voltage (PV) burst according to a PV burst delivery period duty cycle to an electrode disposed within the processing chamber and the PV burst is delivered from a PV source assembly, wherein the PV burst delivery period duty cycle comprises delivering the PV burst for third period of time and halting the delivery of the PV burst for a fourth period of time, wherein the PV burst comprises:
a PV waveform, the PV waveform having a PV waveform duty cycle comprising delivering fifth voltage for sixth period of time and halting delivery of the first voltage for a second period of time and the delivering the first voltage and halting the delivery of the first voltage is cyclically repeated; and
simultaneously delivering the RF waveform and the PV burst, wherein delivering the RF waveform and delivering the PV burst overlap in time.
16 . The method of claim 15 , wherein the device substrate comprises:
a sidewall surface of a sidewall surface of one or more HAR features of the at least one HAR feature-deviates from a desired feature geometry, wherein the desired feature geometry is an approximately straight sidewall surface about normal to the bottom surface.
17 . The method of claim 15 , wherein:
the RF delivery period duty cycle is about 50% to about 95%; and
the PV waveform duty cycle is about 10% to about 50%.
18 . The method of claim 15 , wherein biasing the device substrate comprises delivering the RF waveform to the electrode disposed within the processing chamber.
19 . The method of claim 15 , further comprising maintaining the device substrate at a cryogenic temperature.
20 . The method of claim 15 , wherein the carbon-free fluorine-containing gas comprises fluorine (F 2 ), hydrogen fluoride (HF), or deuterium fluoride (DF), or a combination of hydrogen (H) and a nitrogen fluoride, or a combination of fluorine (F 2 ) and ammonia (NH 3 ).