Method for selective etching of dielectric materials

Abstract

The method includes performing an etching process including supplying a first process gas and a second process gas onto a surface of a substrate on a substrate support in a processing space of a processing chamber for a first duration, where the first process gas includes a fluorine-containing gas and the second process gas includes a nitrogen-containing gas, the method further including performing an annealing process to sublimate by-products formed on the surface of the substrate during the etching process, and supplying the first process gas without supplying the second process gas into the processing space of the processing chamber for a second duration.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE

[0001] Embodiments of the present disclosure generally relate to methods for cleaning the surface of a substrate, and more particularly to methods for selectively etching oxides (eg, silicon dioxide (SiO2)) relative to other dielectric materials (eg, silicon nitride (Si3N4)). [Background technology]

[0002]

[0002] Integrated circuits are formed in and on silicon and other semiconductor substrates. In the case of single crystal silicon, the substrate is made by growing an ingot from a bath of molten silicon and then cutting the solidified ingot into multiple substrates. An epitaxial silicon layer can then be formed on the single crystal silicon substrate to form a defect-free silicon layer, which may be doped or undoped. Semiconductor devices, such as transistors, can be fabricated from the epitaxial silicon layer. The electrical properties of the formed epitaxial silicon layer are generally superior to those of the single crystal silicon substrate.

[0003]

[0003] The surfaces of single crystal silicon and epitaxial silicon layers are susceptible to contamination when exposed to ambient conditions in a typical substrate fabrication facility. For example, handling of the substrate and / or exposure to the ambient environment in the substrate processing facility can cause a native oxide layer to form on the single crystal silicon surface prior to deposition of the epitaxial layer. The presence of the native oxide layer on the single crystal silicon surface can adversely affect the quality of the epitaxial layer subsequently formed on the single crystal surface. However, the large aspect ratios of features formed in other dielectrics, such as silicon nitride (Si3N4) and silicon oxynitride (SiON), can mean that the surface of the substrate being cleaned is adjacent to another dielectric, which must not be damaged or etched by the cleaning process.

[0004]

[0004] Therefore, there is a need for a method for removing oxides selectively relative to other dielectrics. Summary of the Invention

[0005]

[0005] Several embodiments of the present disclosure provide a method for cleaning a surface of a substrate. The method includes performing an etching process, the method including supplying a first process gas and a second process gas onto a surface of a substrate on a substrate support in a processing space of a processing chamber for a first duration, where the first process gas includes a fluorine-containing gas and the second process gas includes a nitrogen-containing gas. The method further includes performing an annealing process to sublimate by-products formed on the surface of the substrate during the etching process, and supplying the first process gas without supplying the second process gas into the processing space of the processing chamber for a second duration.

[0006]

[0006] Embodiments of the present disclosure also provide a method for cleaning a surface of a substrate. The method includes performing an etching process, the etching process including supplying a first process gas and a second process gas onto a surface of a substrate on a substrate support in a processing space of a processing chamber for a first duration, where the first process gas includes a fluorine-containing gas and the second process gas includes a nitrogen-containing gas. The etching process further includes supplying the first process gas without supplying the second process gas into the processing space of the processing chamber for a second duration.

[0007]

[0007] Embodiments of the present disclosure further provide a processing system. The processing system includes a processing chamber and a controller. The controller is configured to cause a processing method to be performed in the processing chamber. The processing method includes performing an etching process, the etching process including supplying a first process gas and a second process gas onto a surface of a substrate on a substrate support in a processing space of the processing chamber for a first duration, where the first process gas includes a fluorine-containing gas and the second process gas includes a nitrogen-containing gas. The processing method further includes performing an annealing process to sublimate by-products formed on the surface of the substrate during the etching process, and supplying the first process gas without supplying the second process gas into the processing space of the processing chamber for a second duration.

[0008]

[0008] So that the features of the present disclosure described above may be understood in detail, a more particular description of the present disclosure briefly summarized above may be had by reference to several embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings depict only exemplary embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure, which may also admit of other equally effective embodiments. [Brief explanation of the drawings]

[0009] [Figure 1A] 1 is a cross-sectional view of an exemplary processing chamber in accordance with one or more embodiments. [Figure 1B] FIG. 1B is an enlarged view of a portion of the processing chamber of FIG. 1A. [Figure 1C] 1 is an enlarged cross-sectional view of an exemplary substrate support according to one or more embodiments. [Figure 2]

[0010] 1 shows a process flow diagram of a method for removing oxides (e.g., silicon oxide (SiO2)) from the surface of a substrate in accordance with at least one embodiment of the present disclosure. [Figure 3]

[0011] An example of oxide removal and nitride removal during an etch cycle time is shown. [Figure 4A]

[0012] 4A and 4B show an example of oxide removal and nitride removal during an etch cycle time. [Figure 4B] 4A and 4B show an example of oxide removal and nitride removal during an etch cycle time. [Figure 4C] An example of the etch selectivity of oxide over nitride is shown. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0013] For ease of understanding, wherever possible, the same reference numerals have been used to designate identical elements common to the figures. It is believed that elements and features of one embodiment may be beneficially incorporated in multiple other embodiments without further recitation.

[0011]

[0014] Embodiments of the present disclosure generally relate to methods and systems for selectively removing oxides (e.g., silicon oxide (SiO)) relative to other dielectric materials (e.g., silicon nitride (SiN)) from the surface of a substrate. The etching processes according to the methods described herein utilize a fluorine-containing primary etchant gas, such as hydrogen fluoride (HF) gas, and a fluorine-containing catalytic gas, such as gaseous ammonia (NH). During the etching process, the supply of the fluorine-containing catalytic gas is reduced or discontinued. Adjusting the duration of the reduced or discontinued supply of the fluorine-containing catalytic gas adjusts the etch selectivity of oxides (e.g., silicon oxide (SiO)) relative to other dielectric materials (e.g., silicon nitride (SiN)); therefore, by appropriately adjusting the reduced or discontinued duration of the supply of the fluorine-containing catalytic gas during the etching process, the etch selectivity can be optimized.

[0012]

[0015] The methods described herein are selective and conformal, and are useful for cleaning high-aspect ratio features. Furthermore, the methods described herein enable high-throughput cleaning of high-aspect ratio features while minimizing loss of dielectric materials (e.g., silicon nitride (Si3N4) and silicon oxynitride (SiON), sidewall spacers, and hardmasks). Additionally, the methods described herein enable isotropic and conformal cleaning of features, whereby, for example, native oxide on the silicon surface of the sidewall (110) is removed in addition to native oxide on the silicon surface (100). After cleaning, the resulting surface can be used for further processing, such as epitaxial growth and / or chemical vapor deposition of Si- and / or Ge-containing layers.

[0013]

[0016] Figure 1A is a cross-sectional view of an exemplary processing chamber 100 according to one or more embodiments adapted to perform a cleaning process, as described in detail below. Figure 1B is an enlarged view of a portion of the processing chamber 100 of Figure 1A. Exemplary processing chambers that may be adapted to perform the cleaning processes described herein include Clarion™ chambers available from Applied Materials, Inc. of Santa Clara, Calif. Chambers from other manufacturers may also be used.

[0014]

[0017] The processing chamber 100 includes a chamber body 102, a lid assembly 104, and a support assembly 106. The lid assembly 104 is disposed on top of the chamber body 102, and the support assembly 106 is disposed at least partially within the chamber body 102. A vacuum system can be used to remove gases from the processing chamber 100. The vacuum system includes a vacuum pump 108 coupled to a vacuum port 110 disposed in the chamber body 102. The processing chamber 100 also includes a controller 112 for controlling processes within the processing chamber 100.

[0015]

[0018] The lid assembly 104 includes multiple stacked components that can provide precursor gases to a processing space 114 within the processing chamber 100. A gas source 116 is coupled to the lid assembly 104 via a first plate 118. The gas source 116 can be configured to provide a non-reactive gas, such as a noble gas. Illustrative and non-limiting examples of non-reactive gases include helium (He), neon (Ne), argon (Ar), krypton (Kr), and / or xenon (Xe), or other non-reactive gas(es).

[0016]

[0019] 1B , opening 120 allows gas(es) to flow from gas source 116 to space 122 formed in second plate 124 of lid assembly 104. A central conduit 126 formed in second plate 124 is adapted to provide gas from space 122 through third plate 128 to mixing chamber 130 formed in fourth plate 132 of lid assembly 104. Central conduit 126 communicates with mixing chamber 130 through opening 134 in third plate 128. Opening 134 can have a diameter smaller than, larger than, or the same as the diameter of central conduit 126. In the embodiment of FIG. 1B , opening 134 has the same or substantially the same diameter as central conduit 126.

[0017]

[0020] The second plate 124 also includes multiple inlets 136 and 138 configured to provide gases to the mixing chamber 130. The inlet 136 is coupled to a first gas source 140, and the inlet 138 is coupled to a second gas source 142. The first gas source 140 and the second gas source 142 may include a process gas and an inert gas (e.g., a noble gas, such as argon and / or helium, utilized as a carrier gas). The first gas source 140 may include a nitrogen-containing gas (e.g., ammonia (NH3)). The second gas source 142 may include a fluorine-containing gas and a hydrogen-containing gas. In one example, the second gas source 142 may include hydrogen fluoride (HF). The first gas source 140 and / or the second gas source 142 may include one or more non-reactive gases.

[0018]

[0021] The first gas source 140 and / or the second gas source 142 may include one or more ampoules, one or more bubblers, and / or one or more liquid vaporizers configured to provide process gas. For example, if a liquid precursor (e.g., hydrogen fluoride (HF)) is used, the first gas source 140 and / or the second gas source 142 may include a liquid vaporizer in fluid communication with a liquid precursor source (not shown). The liquid vaporizer can be used to vaporize the liquid precursor supplied to the lid assembly 104. Although not shown, the liquid precursor source may include, for example, one or more ampoules of precursor liquid and solvent liquid, a shut-off valve, and a liquid flow meter (LFM). As an alternative to a liquid vaporizer, a bubbler can be used to supply the liquid precursor(s) to the chamber. In such a case, an ampoule of the liquid precursor is connected to the process space of the chamber via the bubbler.

[0019]

[0022] 1B , in some configurations, the inlet 136 is coupled to the mixing chamber 130 via a cylindrical channel 144 (shown in dashed lines) and a plurality of holes 146 formed in the third plate 128. The inlet 138 is coupled to the mixing chamber 130 via a cylindrical channel 148 (shown in dashed lines) and a plurality of holes 150 formed in the third plate 128. The holes 146, 150 formed in the third plate 128 are generally sized to allow a uniform flow of gases. The gases are provided into the mixing chamber 130 from their respective gas sources 140, 142. In one configuration, the holes 150 have a diameter smaller than the width of the opening defined by the opposing sidewalls of the cylindrical channel 148 formed in the second plate 124. The holes 150 are typically distributed circumferentially about the centerline of the cylindrical channel 148 to provide a uniform flow of fluid into the mixing chamber 130. In one configuration, the holes 146 have a diameter smaller than the width of the opening defined by the opposing sidewalls of the cylindrical channel 144 formed in the second plate 124. The holes 146 are typically distributed circumferentially about the centerline of the cylindrical channel 144 to provide uniform fluid flow into the mixing chamber 130.

[0020]

[0023] The inlets 136 and 138 provide flow paths for the respective fluids that pass laterally through the second plate 124, turn toward the third plate 128, and pass through the third plate 128 to the mixing chamber 130. The lid assembly 104 also includes a fifth plate or first gas distributor 152. The fifth plate or first gas distributor 152 may be a gas distribution plate such as a showerhead. In this case, the various gases mixed within the lid assembly 104 flow through perforations 154 formed therein. The perforations 154 are in fluid communication with the mixing chamber 130 to provide a flow path from the mixing chamber 130 through the first gas distributor 152. Referring back to FIG. 1A , a blocker plate 156 and a gas distribution plate (such as the second gas distributor 158) are disposed below the lid assembly 104. The gas distribution plate may be a gas distribution plate such as a showerhead.

[0021]

[0024] The support assembly 106 may include a substrate support 160 for supporting a substrate 162 thereon during processing. The substrate support 160 may be coupled to an actuator 164 by a shaft 166. The shaft 166 extends through a centrally located opening formed in the bottom of the chamber body 102. The actuator 164 may be flexibly sealed to the chamber body 102 by a bellows (not shown) that prevents vacuum leakage around the shaft 166. The actuator 164 may move the substrate support 160 vertically within the chamber body 102 between a processing position and a loading position. The loading position is slightly below a tunnel opening (not shown) formed in a sidewall of the chamber body 102.

[0022]

[0025] The substrate support 160 has a flat or substantially flat substrate support surface for supporting a substrate 162 to be processed thereon. The substrate support 160 can be moved vertically within the chamber body 102 by an actuator 164. The actuator 164 is coupled to the substrate support 160 by a shaft 166. In some processes, the substrate support 160 can be raised to a position adjacent to the lid assembly 104 to control the temperature of the substrate 162 being processed. Thus, the substrate 162 can be heated by radiation emitted from the second gas distributor 158 or another radiation source, or by convection or conduction from the second gas distributor 158 through an intervening gas. In some process steps, the substrate 162 can be placed on lift pins 168 to perform a further thermal treatment step, such as an annealing step.

[0023]

[0026] 1A. The substrate support 160 includes a thermal control plenum 170 in fluid communication with a fluid supply conduit 172 and a fluid return conduit 174. Each of the fluid supply conduit 172 and the fluid return conduit 174 is disposed through the shaft 166. The thermal control plenum 170 may perform a cooling function for the substrate support 160 by circulating a cooling fluid through the fluid supply line 172 into the thermal control plenum 170 and out through the fluid return line 174.

[0024]

[0027] The substrate support 160 may also include multiple heaters, which in this embodiment include a first heater 176 and a second heater 178. The first heater 176 and the second heater 178 are disposed in a substantially coplanar relationship within the substrate support 160 at locations to enable thermal coupling between the heaters and the substrate support surface. The first heater 176 is disposed around the periphery of the substrate support 160, and the second heater 178 is disposed in a central area of the substrate support 160 to provide zoned temperature control. Each of the first heater 176 and the second heater 178 may be a resistive heater coupled to one or more power sources (not shown) by respective power conduits 180 and 182. Each of the power conduits 180 and 182 is disposed through the shaft 166.

[0025]

[0028] In the process, temperature control may be provided by simultaneous operation of the thermal control plenum 170, the first heater 176, and the second heater 178. The thermal control plenum 170 may be supplied with a cooling fluid, as described above. Power may be provided to the first heater 176 and the second heater 178 as resistive heaters. In this manner, separate control circuits may be tuned to provide a fast response for one item (e.g., the first heater 176 and the second heater 178) and a slower response for the thermal control plenum 170, or vice versa. Different control parameters may be applied to the thermal control plenum 170, the first heater 176, and the second heater 178 to achieve at least an optimized zone temperature control system.

[0026]

[0029] As shown in FIG. 1C , a separate lift member 184 may be included within the support assembly 106. Recesses may be provided in the substrate support surface to accommodate the lift pins 168 of the lift member 184 when a substrate is placed on the substrate support surface. The lift member 184 may be coupled to a lift actuator 186 by an extension of the lift member 184 disposed through the shaft 166. The lift actuator 186 may vertically move the lift member 184 to lift the substrate 162 from the substrate support surface toward the first gas distributor 152. The lift member 184 may be a hoop, such as an open hoop or a closed hoop, and may be U-shaped, circular, horseshoe-shaped, or any convenient shape. The lift member 184 has a thickness to provide structural strength when lifting a substrate. In one example, the lift member 184 is made of a ceramic material and is approximately 1 mm thick.

[0027]

[0030] 2 illustrates a process flow diagram of a method 200 for removing oxides (e.g., silicon oxide (SiO)) with high selectivity to other dielectric materials (e.g., silicon nitride (SiN)) from the surface of a substrate in accordance with at least one embodiment of the present disclosure. While the method illustrated in FIG. 2 is described sequentially, it should be noted that other process sequences including one or more steps omitted and / or added and / or rearranged in another desired order are within the scope of multiple embodiments of the disclosure provided herein.

[0028]

[0031] The method 200 can be performed in a processing chamber, such as the processing chamber 100 shown in Figures 1A and 1B.

[0029]

[0032] The term "substrate" as used herein refers to a layer of material that serves as a foundation for subsequent processing operations and that includes the surface to be cleaned. The substrate may be a silicon-based material or any suitable insulating or conductive material, as appropriate. The substrate may be crystalline silicon (e.g., Si <100> or Si <111> ), silicon oxide, strained silicon, silicon germanium, doped or undoped polysilicon, doped or undoped silicon wafers and patterned or unpatterned wafers, silicon-on-insulator (SOI), carbon-doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, or sapphire.

[0030]

[0033] The method 200 begins with an etching process at block 210. The etching process may be an isotropic and conformal dry etching process. In the etching process, one or more process gases including a fluorine-containing gas, such as hydrogen fluoride (HF) gas, and a nitrogen-containing gas, such as gaseous ammonia (NH), trimethylamine (TMA), triethylamine (TEA), ammonia (NH), nitric oxide (NO), or nitrogen dioxide (NO), are supplied to a substrate disposed on a substrate support, such as substrate support 160, in a processing space, such as processing space 114 of a processing chamber. The fluorine-containing gas, such as hydrogen fluoride (HF) gas, may be routed through an inlet from one gas source, such as inlet 136 from a first gas source 140, and the nitrogen-containing gas, such as gaseous ammonia (NH), may be routed through another inlet from another gas source, such as inlet 138 from a second gas source 142. In some embodiments, non-reactive process gases such as helium (He), neon (Ne), argon (Ar), krypton (Kr), and / or xenon (Xe) can be used in conjunction with one or more process gases as carrier gases and / or purge gases during substrate processing.

[0031]

[0034] During the etching process, the substrate support is maintained at a low temperature of about 10° C. to about 15° C., e.g., about 14° C., by circulating a temperature control fluid through a thermal control plenum 170. The substrate support may be powered to provide radial temperature control. The processing chamber is maintained at a pressure between about less than 1 Torr and about 20 Torr, e.g., about 5 Torr. A fluorine-containing gas, such as hydrogen fluoride (HF) gas, is provided as a primary etchant to etch oxide. A nitrogen-containing gas, such as gaseous ammonia (NH3), is provided as a catalyst to convert silicon oxide (SiO2) and silicon nitride (Si3N4) into by-products on the surface of the substrate, such as salts formed with ammonium fluorosilicate ((NH4)2SiF6). In some embodiments, the substrate support is maintained at a temperature between about 40° C. and about 50° C. during the etching process.

[0032]

[0035] The etching process begins with a presoak phase followed by a primary etchant-only phase. During the presoak phase, both a fluorine-containing primary etchant and a fluorine-containing catalytic gas are supplied. During the primary etchant-only phase, the supply of the fluorine-containing catalytic gas is stopped or reduced. In some embodiments, for an etching cycle time between about 15 and about 20 seconds, the presoak phase lasts between about 5 and about 60 seconds, e.g., about 15 seconds, and the primary etchant-only phase lasts between about 5 and about 60 seconds, e.g., about 20 seconds.

[0033]

[0036] During the presoak phase and the primary etchant-only phase, a fluorine-containing primary etchant gas, such as hydrogen fluoride (HF) gas, may be supplied at a flow rate between about 2 sccm and about 40 sccm, e.g., about 5 sccm. A fluorine-containing catalyst gas, such as gaseous ammonia (NH), may be supplied at a flow rate between about 5 sccm and about 50 sccm, e.g., about 12.5 sccm, during the presoak phase and may not be supplied during the primary etchant-only phase. In some embodiments, a fluorine-containing catalyst gas, such as gaseous ammonia (NH), is supplied at a lower flow rate (e.g., less than about 10 sccm) during the primary etchant-only phase than during the presoak phase.

[0034]

[0037] Conventionally, etching processes for oxide removal utilize both a fluorine-containing gas, such as hydrogen fluoride (HF) gas, and a nitrogen-containing gas, such as gaseous ammonia (NH). The inventors have shown that, as shown in FIG. 3, during an etching cycle time of approximately 38 seconds, the etch rate of oxide (e.g., silicon oxide (SiO)) remains substantially constant (i.e., oxide removal is substantially linear with respect to etching time), while the etch rate of nitride (e.g., silicon nitride (SiN)) increases (i.e., the slope of nitride removal increases with etching time). That is, the etch selectivity of oxide relative to nitride decreases as the etching process progresses. The inventors have also shown, as shown in FIGS. 4A and 4B, that when the flow of a nitrogen-containing gas, such as gaseous ammonia (NH), is stopped or reduced during the etching cycle time (e.g., approximately 15 seconds from the start of the cycle time in FIG. 4A), the etch rate of nitride does not increase (i.e., the slope of nitride removal does not increase) during the primary etchant-only phase after the nitrogen-containing gas is stopped.

[0035]

[0038] The oxide to nitride etch selectivity varies with the duration of the primary etchant-only phase per etch cycle time. In one example shown in Figure 4C, the etch selectivity varies between about 20 and 40, with a maximum value of 40 following a primary etchant-only phase of about 15 seconds per etch cycle time between 25 and about 30 seconds.

[0036]

[0039] In some embodiments, the etching process in block 210 is based on the SiConi™ etching process. The SiConi™ etching process is a remote plasma-assisted dry etch. In this case, the fluorine-containing gas comprises a nitrogen trifluoride (NF3) plasma. During the etching process, the substrate support may be maintained at a temperature between about 30° C. and about 50° C., for example, about 35° C.

[0037]

[0040] In block 220, an annealing process is performed to sublimate by-products formed on the surface of the substrate during the etching process in block 210. The substrate support is heated to a higher temperature of greater than about 80° C., e.g., 100° C. or higher. The processing chamber is maintained at a pressure between about 1 Torr and about 10 Torr, e.g., about 3 Torr. In some embodiments, thermal energy is provided via radiation, convection, and / or conductive heat transfer processes. In the annealing process, by-products formed in block 210, such as salts formed with ammonium fluorosilicate ((NH4)2SiF6), are sublimated and removed from the substrate.

[0038]

[0041] In block 230, a cooling process is performed to cool the substrate support to a lower etching temperature of between about 10° C. and about 15° C., for example, about 14° C., and the cycle of the etching process in block 210 and the annealing process in block 220 is repeated until the desired oxide removal is achieved. The temperature of the substrate support can be cycled between the higher sublimation temperature in block 220 and the lower etching temperature in block 210, for example, by positioning the substrate support closer to the lid for the annealing process in block 220 and further from the lid for the etching process in block 210. In some embodiments, the cycle of the etching process in block 210 and the annealing process in block 220 is repeated two or three times.

[0039]

[0042] In block 240, an epitaxial growth process is performed to form an epitaxial layer on the cleaned surface of the substrate. The epitaxial layer can be any suitable semiconductor material, such as crystalline silicon, germanium, or silicon germanium, or a III-V or II-VI compound. The epitaxial process in block 240 can be performed in a vapor phase epitaxy deposition chamber, such as an Epi chamber available from Applied Materials, Inc. of Santa Clara, California (Centura™ Epi chamber).

[0040]

[0043] The methods described herein enable the selective removal of unwanted oxides (e.g., silicon oxide (SiO2)) on the surface of a substrate having high aspect ratio device features. The etching process according to the methods described herein is conformal and selective to other dielectric materials (e.g., Si3N4). Etch selectivity can be optimized by appropriately adjusting the reduced or discontinued duration of the supply of a fluorine-containing catalytic gas, such as gaseous ammonia (NH3), while continuously supplying a fluorine-containing primary etchant gas, such as hydrogen fluoride (HF) gas.

[0041]

[0044] The methods described herein enable high-throughput cleaning of high-aspect ratio features while minimizing loss of dielectric materials (e.g., silicon nitride (Si3N4) and silicon oxynitride (SiON), sidewall spacers, and hardmasks). In addition, the methods described herein enable isotropic and conformal cleaning of features, whereby, for example, native oxide on the silicon surface of the sidewalls (110) is removed in addition to native oxide on the silicon surface (100). After cleaning, the resulting surface can be used for further processing, such as epitaxial growth and / or chemical vapor deposition of Si- and / or Ge-containing layers.

[0042]

[0045] While the forgoing description is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, the scope of which is defined by the claims that follow.

Claims

1. 1. A method for cleaning a surface of a substrate, comprising: performing an etching process, supplying a first process gas and a second process gas onto a surface of a substrate on a substrate support in a processing space of a processing chamber for a first duration, the first process gas comprising a fluorine-containing gas and the second process gas comprising a nitrogen-containing gas; and performing an etching process including supplying the first process gas without supplying the second process gas into the processing space of the processing chamber for a second duration; and performing an annealing process to sublimate by-products formed on the surface of the substrate during the etching process.

2. the fluorine-containing gas includes hydrogen fluoride (HF); The nitrogen-containing gas is gaseous ammonia (NH 3 10. The method of claim 1, comprising:

3. the first duration is between 5 and 60 seconds; The method of claim 1 , wherein the second duration is between 5 and 60 seconds.

4. the flow rate of the fluorine-containing gas is between 2 sccm and 40 sccm; 10. The method of claim 1, wherein the flow rate of the nitrogen-containing gas is between 5 sccm and 50 sccm.

5. 10. The method of claim 1, wherein the processing chamber is maintained at a first pressure between less than 1 Torr and 20 Torr during the etching process and at a second pressure between 1 Torr and 10 Torr during the annealing process.

6. 10. The method of claim 1, wherein the substrate support is maintained at a first temperature between 10 and 15°C during the etching process and at a second temperature above 80°C during the annealing process.

7. cooling the substrate support to the first temperature; and The method of claim 6 , further comprising repeating the etching process and the annealing process.

8. The method of claim 1 further comprising forming a film on the substrate by a vapor phase epitaxy process.

9. 1. A method for cleaning a surface of a substrate, comprising: performing an etching process, supplying a first process gas and a second process gas onto a surface of a substrate on a substrate support in a processing space of a processing chamber for a first duration, the first process gas comprising a fluorine-containing gas and the second process gas comprising a nitrogen-containing gas; and performing an etching process comprising supplying the first process gas without supplying the second process gas into the processing space of the processing chamber for a second duration.

10. the fluorine-containing gas includes hydrogen fluoride (HF); The nitrogen-containing gas is gaseous ammonia (NH 3 10. The method of claim 9, comprising:

11. 10. The method of claim 9, further comprising performing an annealing process to sublimate by-products formed on the surface of the substrate during the etching process.

12. the first duration is between 5 and 60 seconds; the second duration is between 5 and 60 seconds; the flow rate of the fluorine-containing gas is between 2 sccm and 40 sccm; the flow rate of the nitrogen-containing gas is between 5 sccm and 50 sccm; 12. The method of claim 11, wherein the processing chamber is maintained at a first pressure of between less than 1 Torr and 20 Torr during the etching process and at a second pressure of between 1 Torr and 10 Torr during the annealing process.

13. cooling the substrate support to a first temperature; and further comprising repeating the etching process and the annealing process; 12. The method of claim 11, wherein the substrate support is maintained at a first temperature between 10 and 15°C during the etching process and at a second temperature above 80°C during the annealing process.

14. 1. A processing system comprising: a processing chamber; a controller configured to cause a process method to be performed in the process chamber, the process method comprising: performing an etching process, supplying a first process gas and a second process gas onto a surface of a substrate on a substrate support in a processing space of the processing chamber for a first duration, the first process gas comprising a fluorine-containing gas and the second process gas comprising a nitrogen-containing gas; and performing an etching process including supplying the first process gas without supplying the second process gas into the processing space of the processing chamber for a second duration; and performing an annealing process to sublimate by-products formed on the surface of the substrate during the etching process.

15. the fluorine-containing gas includes hydrogen fluoride (HF); The nitrogen-containing gas is gaseous ammonia (NH 3 15. The processing system of claim 14, comprising:

16. the first duration is between 5 and 60 seconds; 15. The processing system of claim 14, wherein the second duration is between 5 and 60 seconds.

17. the flow rate of the fluorine-containing gas is between 2 sccm and 40 sccm; 15. The processing system of claim 14, wherein the flow rate of said nitrogen containing gas is between 5 sccm and 50 sccm.

18. 15. The processing system of claim 14, wherein said processing chamber is maintained at a first pressure between less than 1 Torr and 20 Torr during said etching process and at a second pressure between 1 Torr and 10 Torr during said annealing process.

19. 15. The processing system of claim 14, wherein the substrate support is maintained at a first temperature between 10 and 15 degrees Celsius during the etching process and at a second temperature above 80 degrees Celsius during the annealing process.

20. The processing method comprises: cooling the substrate support to the first temperature; and 20. The processing system of claim 19, further comprising repeating the etching process and the annealing process.

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