Electrostatic chucking process

One or more embodiments described herein generally relate to methods for chucking and de-chucking a substrate to/from an electrostatic chuck used in a semiconductor processing system. Generally, in embodiments described herein, the method includes: (1) applying a first voltage from a direct current (DC) power source to an electrode disposed within a pedestal; (2) introducing process gases into a process chamber; (3) applying power from a radio frequency (RF) power source to a showerhead; (4) performing a process on the substrate; (5) stopping application of the RF power; (6) removing the process gases from the process chamber; and (7) stopping applying the DC power.

BACKGROUND

Field

One or more embodiments described herein generally relate to semiconductor processing systems, and more particularly, to methods for chucking and de-chucking a substrate to/from an electrostatic chuck used in a semiconductor processing system.

Description of the Related Art

Electrostatic chucking (ESC) pedestals, commonly known as electrostatic chucks, are used in semiconductor device manufacturing to securely hold a substrate in a processing position within a processing volume of a process chamber, using an electrostatic chucking force. The chucking force is a function of the potential between a DC voltage provided to a chucking electrode embedded in a dielectric material of the pedestal and a substrate disposed on a surface of the dielectric material.

In the manufacture of semiconductor devices, integrated circuits have evolved into complex devices that can include millions of transistors, capacitors, and resistors on a single chip. The evolution of chips designs continually require greater circuit density, which will result in an increased substrate bow of a multi-stack structure. Flattening the substrate to the surface of the pedestal facilitates securing the substrate during plasma processes and ensures correct radio frequency (RF) coupling to ground for chamber longevity and uniform film deposition. Loss of chucking becomes a risk as the distance of the substrate from the chucking electrode increases. As such, a higher electrostatic chucking voltage is necessary to clamp the substrate to the pedestal surface. The higher electrostatic chucking voltage may cause a DC plasma discharge adjacent to the substrate. The DC plasma discharge may damage the substrate during processing.

Furthermore, the evolution of chip designs have led to modified pedestal surface designs that include multiple points where the substrate contacts the pedestal surface, commonly referred to as posts. However, although the posts desirably provide repeatable contact to minimize particle defects on the substrate backside, due to the modified structure of the pedestal surface, in conventional processes, the substrate can often become damaged or break. The posts may induce damage at a higher rate for increased electrostatic chucking voltage and when the position of the substrate is not adequately controlled. Damages on the substrate backside at the posts result in lithographic defocus, and significantly impact production yield.

Accordingly, there is a need for methods of chucking and de-chucking a substrate to an electrostatic chuck that reduce lithographic defocus and yield loss by eliminating backside damages.

SUMMARY

One or more embodiments described herein generally relate to methods for chucking and de-chucking a substrate to/from an electrostatic chuck used in a semiconductor processing system.

In one embodiment, a method for processing a substrate within a process chamber includes applying a direct current to an electrode disposed within a pedestal on which the substrate is disposed within the process chamber; flowing one or more process gases into the process chamber subsequent to applying the direct current to the electrode; applying radio frequency (RF) power to a showerhead within the process chamber, subsequent to flowing one or more process gases into the process chamber; processing the substrate subsequent to applying RF power; stopping the application of the RF power subsequent to processing the substrate; removing the one or more process gases from the process chamber subsequent to stopping the application of RF power; and stopping the application of the DC power subsequent to removing the one or more process gases.

In another embodiment, a method for processing a substrate includes (a) positioning the substrate on a surface of a pedestal, wherein the pedestal is at a first spacing from a showerhead, (b) applying a DC voltage at a first DC voltage level to an electrode disposed within the pedestal, (c) flowing one or more process gases into the process chamber through the showerhead, (d) applying an RF power at a first RF power level to the showerhead within the process chamber, (e) increasing the DC voltage and the RF power to a second DC voltage level and a second RF power level either prior to, during, or both prior to and during processing of the substrate, (f) decreasing the DC voltage and the RF power to a third DC voltage level and a third RF power level after processing of the substrate, (g) moving the pedestal within the process chamber to a second spacing from the showerhead, (h) stopping the application of RF power to the showerhead, (i) removing the one or more process gases from the process chamber, and (j) stopping the application of the DC voltage to the electrode.

In yet another embodiment, a method for processing a substrate includes positioning the substrate on a surface of a pedestal, wherein the pedestal is at a first spacing from a showerhead within a process chamber; applying a DC voltage at a first DC voltage level to an electrode disposed within the pedestal; flowing a first process gas into the process chamber through the showerhead after the application of the DC voltage at a first DC voltage level; applying radio frequency (RF) power to the showerhead within the process chamber at a first RF power level; moving the pedestal to a second spacing from the showerhead, wherein the second spacing is closer to the showerhead than the first spacing; flowing a second process gas mixture into the process chamber through the showerhead; increasing the DC voltage and the RF power to a second DC voltage level and a second RF power level to either prior to, during, or both prior to and during the performance of a process on the substrate; decreasing the DC voltage and the RF power after performing the process on the substrate to a third DC voltage level and a third RF power level; flowing the first process gas into the process chamber through the showerhead while removing the second process gas mixture from the process chamber after performing the process on the substrate; moving the pedestal within the process chamber to a third spacing from the showerhead; stopping the application of the RF power; removing the first process gas from the process chamber after stopping the application of the RF power; and stopping the application of the DC power after removing the first process gas from the process chamber.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth to provide a more thorough understanding of the embodiments of the present disclosure. However, it will be apparent to one of skill in the art that one or more of the embodiments of the present disclosure may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring one or more of the embodiments of the present disclosure.

One or more embodiments described herein generally relate to methods for chucking and de-chucking a substrate to/from an electrostatic chuck used in a semiconductor processing system. In embodiments described herein, pedestals within process chambers have modified pedestal surfaces that include multiple points where the substrate contacts the pedestal surface, commonly referred to as posts. In conventional methods for chucking a substrate to the modified pedestal surface, a first process gas is introduced into the process chamber. A radio frequency (RF) power is then generated from an RF power source, generating an RF plasma within the process chamber. Thereafter, a direct current (DC) voltage is generated from a DC power source to an electrode disposed within the pedestal to apply a DC electrostatic chucking bias, chucking the substrate to the pedestal surface via an electrostatic chucking force. Subsequent to the chucking of the substrate, a process is performed on the substrate within the process chamber. Subsequent the process, the DC electrostatic chucking is turned off and then the RF power is turned off. Once the DC electrostatic chucking and RF power are off, the gas flow into the process chamber is stopped.

However, the conventional methods described above create a high degree of movement for the substrate at the introduction of gases without the chucking force present, which can lead to substrate breakage. Additionally, in the conventional methods, backside damages may occur as the substrate undergoes force that moves the substrate with respect to the posts on the pedestal surface. The force can be due to the movement or due to thermal expansion. In the case of thermal expansion, the difference between the temperature of the substrate and the pedestal surface at the posts can cause localized damages as the substrate expands or contracts with respect to the pedestal surface.

In the methods for chucking a substrate to the modified pedestal surface as described in embodiments herein, a DC voltage is first generated from a direct current (DC) power source to an electrode disposed within the pedestal, chucking the substrate to the pedestal surface via an electrostatic chucking force. After the substrate is chucked with an electrostatic chucking force, a first process gas may be introduced into the process chamber. After the first process gas is introduced, RF power is generated from an RF power source, generating an RF plasma within the process chamber. Applying the chucking force prior to RF plasma generation advantageously controls the position of the substrate, preventing the substrate from breaking or being damaged by unintentional movement of the substrate on the pedestal surface during the introduction of the first process gas. Additionally, first applying the chucking force improves yield by reducing lithographic defocus by eliminating backside damages.

After RF power is applied to generate the RF plasma, a process is performed on the substrate. The process may be a deposition process, etch process, plasma treatment, or another process. Subsequent the performance of the process on the substrate, the RF power is turned off. After the RF power is turned off, the first process gas ceases being flown into the process chamber. Subsequent the ceasing of the gas flow, the electrostatic chucking force is turned off before removal of the substrate from the processing chamber.

Overall, in embodiments described herein, the methods generally apply the following sequence: (1) apply a first voltage from a direct current (DC) power source to an electrode disposed within the pedestal; (2) introduce process gases into the process chamber; (3) apply a second voltage from an RF power source; (4) perform a deposition (or other) process on the substrate; (5) stop applying the second voltage from the RF power source; (6) remove the process gases from the process chamber; and (7) stop applying the DC power from the DC power source.

FIG.1is a schematic cross-sectional view of a processing chamber100according to one embodiment described herein. The processing chamber100is a plasma enhanced chemical vapor deposition (PECVD), but it is contemplated that other process chambers may benefit from aspects described herein. An exemplary process chamber which may benefit from the embodiments described herein is the PRODUCER® series of PECVD enabled chambers, available from Applied Materials, Inc., Santa Clara, CA. It is contemplated that other similarly equipped process chambers, including those from other manufacturers, may also benefit from the embodiments described herein.

The process chamber100includes a chamber body102, a pedestal104disposed inside the chamber body102, and a lid assembly106coupled to the chamber body102and enclosing the pedestal104in a processing region120. The lid assembly106includes a gas distributor112. A substrate107is provided to the processing region120through an opening126, such as a slit valve, formed in the chamber body102.

An isolator110, which is a dielectric material such as a ceramic or metal oxide, for example aluminum oxide and/or aluminum nitride, separates the gas distributor112from the chamber body102. The gas distributor112includes openings118for admitting process gases into the processing region120. The process gases are supplied to the process chamber100via a conduit114, and the process gases enter a gas mixing region116prior to flowing through the openings118. An exhaust152is formed in the chamber body102at a location below the pedestal104. The exhaust152may be connected to a vacuum pump (not shown) to remove unreacted species and by-products from the process chamber100.

The gas distributor112is coupled to a power source141, such as an RF generator. The power source141supplies continuous and/or pulsed RF power to the gas distributor112. The power source141is turned on during operation to supply an electric power to the gas distributor112to facilitate formation of a plasma in the processing region120.

The pedestal104is formed from a ceramic material, for example a metal oxide or nitride or oxide/nitride mixture such as aluminum, aluminum oxide, aluminum nitride, or an aluminum oxide/nitride mixture. The pedestal104is supported by a shaft143. The pedestal104is electrically grounded. An electrode128is embedded in the pedestal104. The electrode128may be a plate, a perforated plate, a mesh, a wire screen, or any other distributed arrangement. The electrode128is coupled to an electric power source132via a connection130. The electric power source132supplies power to the electrode128. In some embodiments, the electrode128facilitates electrostatic chucking of the substrate107, such that the pedestal104functions as an electrostatic chuck. When the electrode128functions as an electrostatic chuck, the electric power source132may be utilized to control properties of the plasma formed in the processing region120, or to facilitate generation of the plasma within the processing region120. The pedestal104includes a patterned surface142for supporting the substrate107. The pedestal104also includes a pocket140. The pocket140may alternatively be an edge ring. The substrate107and the pocket140are concentrically disposed on the surface142of the pedestal104.

The power source141, the pedestal104, and the electric power source132may all be connected to a controller150. The controller150controls the application of power to each of the power source141, the pedestal104, and the electric power source132. The controller150may increase or decrease the power supplied to each of the power source141, the pedestal104, and the electric power source132. The controller150may integrate the utilization of the power source141, the pedestal104, and the electric power source132, such that the supply of power to each of the power source141, the pedestal104, and the electric power source132are coordinated. In some embodiments, each of the power source141, the pedestal104, and the electric power source132may be connected to individual controllers150. In the embodiment in which each of the power source141, the pedestal104, and the electric power source132are connected to different controllers, each of the controllers150may communicate with one another through either a wired or wireless connection.

FIG.2Ais a top plan view of the pedestal104ofFIG.1having one embodiment of a patterned surface142. The pedestal104shown inFIG.2Aincludes a peripheral ledge202that is surrounded by the pocket140. The patterned surface142includes two distinct regions, such as a central region200surrounded by a peripheral region205. The patterned surface142includes a plurality of posts210that have an upper surface215that defines a substrate receiving surface220. The posts210within the central region200may have different heights than the posts210within the peripheral region205. The upper surface215of each of the plurality of posts210are substantially coplanar. The relative heights of the posts210within the central region200and the peripheral region205are shown in greater detail inFIG.2B.

Each of the plurality of posts210are shown as being rectangular in plan view, but the posts210may be circular, oval, hexagonal, or other shape in plan view. In some embodiments, which may be combined with other embodiments, the central region200has a surface area less than a surface area of the peripheral region205. For example, if the diameter of the patterned surface142is about 12 inches, the surface area of the peripheral region205is about 113 square inches, and the surface area of the central region200is about 11 square inches. In some embodiments, which may be combined with other embodiments, the surface area of the peripheral region205is about 900% greater than a surface area of the central region200. The upper surface215of each of the plurality of posts210includes a surface roughness (average surface roughness or Ra) of about 20 micro inches to about 60 micro inches, such as about 30 micro inches to about 50 micro inches or about 35 micro inches to about 45 micro inches. In some embodiments, the upper surface215of each of the plurality of posts210includes a surface roughness of about 40 micro inches. The patterned surface142also includes lift pin holes212. The lift pin holes212are positioned within the peripheral region of the patterned surface142and are spaced between the posts210. The lift pin holes212are used along with respective lift pins (not shown) to lower and raise the substrate during transfer to/from the process chamber100.

FIG.2Bis a sectional view of the pedestal104ofFIG.2A. As shown inFIG.2B, the plurality of posts210includes a plurality of first posts225A in the peripheral region205and a plurality of second posts225B in the central region200. A height230of each of the plurality of first posts225A is greater than a height235of the plurality of second posts225B. The height230and the height235are measured from an upper surface or base surface232of the pedestal104. In some embodiments, the height230of each of the plurality of first posts225A is about 0.002 inches to about 0.0024 inches, such as about 0.0022 inches. In some embodiments, which may be combined with other embodiments, the height235of each of the plurality of second posts225B is about 0.0005 inches to about 0.0007 inches, such as about 0.0006 inches. While only two different heights of the posts210are shown (i.e., height230and height235), the patterned surface142may include another plurality of posts at a height that is different than the height230and the height235.

The difference in the heights230and235, and/or the difference in the surface areas of the central region200and the peripheral region205, changes heat transfer rates between the pedestal104and a pedestaled thereon. The modified heat transfer rates modify the temperature profile of the substrate. In some embodiments, the difference in the heights230and235, and/or the difference in the surface areas of the central region200and the peripheral region205improves temperature uniformity in the substrate which improves deposition uniformity on the substrate. In some embodiments, having the height235of each of the plurality of second posts225B that is less than the height230of each of the plurality of first posts225A increases temperature in the center of a substrate. Increasing the temperature at a center of the substrate may improve the temperature uniformity of the entire substrate, which improves deposition uniformity on the substrate.

The heights230and235of the posts210make the base surface232of the pedestal104a multi-level structure. For example, the base surface232of the central region200defines a raised surface240as compared to the base surface232of the peripheral region205, which is referenced as a recessed surface245compared to the raised surface240. The raised surface240and the recessed surface245of the pedestal104shown inFIG.2Bdefines a profile, such as an upside-down or reverse U-shaped profile250.

FIG.3Adepict a method300A according to embodiments described herein. In operation302, the substrate107is positioned on the pedestal104in the process chamber100. During the positioning of the substrate107on the pedestal104, the pedestal104is at a substrate receiving position and the substrate107is at a pre-process position. When the pedestal104is in the substrate receiving position, the pedestal is spaced from the gas distributor at a distance of about 3500 mils to about 5000 mils, such as about 3750 mils to about 4750 mils, such as about 4000 mils to about 4500 mils. While the substrate107is being positioned on the pedestal104, the process chamber100is purged using a purging process gas. Purging the process chamber100removes unwanted gasses and contaminants from the process volume, and fills the process chamber with the purging process gas, which has a high threshold energy of ionization. The purging process gas is introduced at a rate of about 1000 sccm to about 3000 sccm, such as about 1500 sccm to about 2500 sccm. The introduction of the purging process gas is tapered and then stopped towards the end of the operation302and after the substrate107has been placed on the pedestal104.

In operation304, the electric power source132is turned on after operation302. In operation304, the process chamber100is filled with a first process gas, such as a helium gas from operation302. The electric power source132is a DC power source, which applies a DC voltage to the electrode128within the pedestal104and chucks the substrate107to the patterned surface142. The DC voltage may be a first DC voltage level of about 300 volts to about 1000 volts, such as about 300 volts to about 600 volts, such as about 300 volts to about 500 volts, such as about 350 volts to about 450 volts, such as about 400 volts. Chucking the substrate107before the subsequent operations in this method provides the advantage of controlling the position of the substrate107and helps prevent the substrate107from moving. Stability of the substrate107prevents backside damages that may occur when the substrate107moves, as movement causes force between the posts210on the patterned surface142and the substrate107. DC voltages disclosed herein mitigate undesirable electrostatic discharge of the first process gases within the process chamber and further introduced in operation306, particularly in combination with other disclosed process parameters, such as gas composition, internal chamber pressure, and substrate spacing.

In operation306, one or more first process gases are flown into the process chamber100through the gas distributor112. Operation306is performed after operation304. The first process gases may include helium or other similar process gases. Using helium gas provides the advantage of having higher thermal conductivity which helps planarize local temperature variations on the patterned surface142, which can help prevent backside damages through uniform thermal expansion. It is contemplated there are other process gasses capable of being utilized in place of helium as the first process gas. The first process gases have high threshold energy to eliminate ionization during substrate chucking. Helium gas provides a high bias breakdown medium for DC discharges, which improves stability when the pedestal104is spaced further apart from the gas distributor112. Helium has been shown to have a drastically higher bias breakdown voltage than gasses such as argon when compared under process conditions similar to those described herein. When comparing the amount of defects on a substrate while using helium, it was found that the number of defects on the substrate can be reduced by between 90% and 95% when compared to using argon as the first process gas.

The first gas is introduced at a rate of about 1 sccm to about 10,000 sccm, such as about 1 sccm to about 4000 sccm, such as about 1000 sccm to about 3000 sccm, such as about 2000 sccm. In some embodiments, the flow rate of the process gas into the process chamber100during operation306may be ramped up from an initial flow rate of about 0 sccm to a final flow rate described in one of the ranges above. Ramping of the process gas further minimizes substrate movement.

During operation306, the pressure within the chamber is increased to a pressure of about 5 Torr to about 15 Torr, such as about 6 Torr to about 12 Torr, such as about 7 Torr to about 10 Torr. The pressure within the chamber is maintained at the pressure during substrate processing.

In operation308, an electric power source141is turned on. Operation308is performed after operation306. The electric power source141may be an RF generator which applies an RF power to the gas distributor112. The RF power may be a first RF power level and is in the range of about 100 watts to about 6000 watts, such as about 150 watts to about 3000 watts, such as about 200 to about 2000 watts, such as about 250 to about 500 watts, such as about 350 watts. It is contemplated that the range of the first RF power level may be greater than about 6000 watts, such as greater than about 7000 watts, such as greater than about 8000 watts, such as greater than about 9000 watts, such as greater than about 10000 watts. In some embodiments, the first RF power level is greater than about 100 watts, such as greater than about 150 watts, such as greater than about 200 watts, such as greater than about 250 watts. In some embodiments, the range of the first RF power level is about 100 watts to 8000 Watts, such as about 150 watts to about 6000 Watts, such as about 200 watts to about 5000 Watts, such as about 250 watts to 2000 Watts.

In operation314, both the DC voltage and RF power are increased to a second DC voltage level and a second RF power level when substrate processing is performed on the substrate107. Substrate processing may include deposition processes or treatment processes. In some embodiments, the substrate107is subject to an oxidation process. In embodiments in which operation310(FIG.3B) and operation312(FIG.3B) are utilized, the DC voltage and RF power may be increased subsequent to either operation310or operation312. In embodiments in which operation310and operation312are not utilized, the DC voltage and RF power may be increased subsequent to operation308. The second DC voltage level is about 800 volts to about 1100 volts, such as about 900 volts to about 1050 volts, such as 950 volts to about 1000 volts. In some embodiments, the second DC voltage level may be about 980 volts. The RF power is increased to a second RF power level. The second RF power level is about 1000 watts to about 6000 watts, such as about 1000 watts to about 4000 watts, such as about 2000 watts to about 3000 watts, such as about 2250 watts to about 2750 watts. In some embodiments, the second RF power level may be about 2450 watts. In some embodiments, the second RF power level is greater than about 6000 watts, such as greater than about 7000 watts, such as greater than about 8000 watts, such as greater than about 9000 watts, such as greater than about 10000 watts. In some embodiments, the range of the RF power is about 1000 watts to about 5000 Watts, such as about 1500 watts to about 5000 Watts, such as about 2000 watts to about 4000 Watts. The substrate processing is performed during or after the DC voltage and the RF power are increased to a second DC voltage level and a second RF power level. In some embodiments, the substrate processing is performed both during and after the DC voltage and the RF power are increased to the second DC voltage level and the second RF power level.

In operation316, both the DC voltage and RF power are decreased to a third DC voltage level and a third RF power level. The decrease in the DC voltage and RF power is accompanied by a cease of the substrate processing performed on the substrate107in operation314. In some embodiments, which may be combined with other embodiments, the DC voltage and RF power are decreased after substrate processing is performed so that the third DC voltage level and the third RF power level are at the same DC voltage and RF power levels as the first DC voltage level and the first RF power level of operation314. The third DC voltage level is about 300 volts to about 1000 volts, such as about 300 volts to about 600 volts, such as about 300 volts to about 500 volts, such as about 350 volts to about 450 volts, such as about 400 volts. The third RF power level is about 100 watts to about 6000 watts, such as about 150 watts to about 3000 watts, such as about 200 to about 2000 watts, such as about 250 to about 500 watts, such as about 350 watts. It is contemplated that the range of the third RF power level may be greater than about 6000 watts, such as greater than about 7000 watts, such as greater than about 8000 watts, such as greater than about 9000 watts, such as greater than about 10000 watts. In these embodiments, at this stage in the method300, the amount of RF power being supplied is higher than the RF power supplied in conventional methods, which provides a more stable transition from the higher RF power used when the substrate processes performed. This facilitates improved temperature stabilization to prevent backside damages.

In operation322, the power source141is turned off, such that the application of RF power to the gas distributor112is ceased. By turning off the RF power, the plasma creation within the process chamber100may be halted.

In operation324, the flow of the first gas into the process chamber is ceased. The first gas may be removed from the process chamber100in operation324. The first gas is removed from the process chamber100while DC power is still being supplied to the electrode128within the pedestal104. By ceasing the flow of the first gas while DC power is being supplied to the electrode128, the movement of the substrate107caused by the evacuation of the process chamber100is minimized. The pressure within the process chamber100during operation324may be substantially reduced to a near-vacuum pressure. Operation324is performed subsequent to operation322. Also during the removal of the first gas from the process chamber100, the pressure within the process chamber100decreases. The pressure within the process chamber100decreases to a predetermined pressure, such as less than about 5 Torr, such as less than about 3 Torr, such as less than about 2 Torr, such as less than about 1 Torr.

In operation326, the power source132is turned off subsequent to operation324. When the power source132is turned off, the application of the DC voltage is stopped and the chucking of the substrate107on the patterned surface is ceased. Once the chucking of the substrate107has ceased, the substrate107may be removed from the patterned surface142.

FIG.3Bdepict a method300B according to embodiments described herein. The method300B ofFIG.3Bis similar to the method300A ofFIG.3A, but may include several additional process operations, such as operation303, operation310, operation312, operation318, and operation320as described herein.

In optional operation303(FIG.3B), the pedestal104is moved from a substrate receiving position to a first spacing from the gas distributor. The first spacing is about 200 mils to about 3000 mils, such as about 200 mils to about 1000 mils, such as about 450 mils to about 750 mils from the gas distributor112. In some embodiments, the pedestal104is spaced about 550 mils from the gas distributor112, although other positions are also possible. The selected spacing facilitates chucking of a substrate without inadvertent plasma generation.

In optional operation310(FIG.3B), the pedestal104is moved within the process chamber100to be positioned closer to the gas distributor112. Operation310is performed between operation308and operation310as previously described. In this embodiment, the pedestal104is moved to a second spacing. The second spacing is between about 200 mils to about 400 mils from the gas distributor112, such as about 250 mils to about 350 mils, such as about 300 mils from the gas distributor112.

Operation312is performed subsequent to or simultaneously with operation310. In optional operation312(FIG.3B), a second process gas mixture is flowed into the process chamber100through the gas distributor112while the flow of the first process gas into the process chamber100is stopped. In some embodiments, the first process gas may be removed from the process chamber100during this operation. The second process gas mixture includes one or more of carrier gases and process/deposition gases, such as a mixture of argon and propene. Other carrier gases and process/deposition gases may also be used, such as nitrogen, ethylene, oxygen, tungsten hexafluoride, diborane, tungsten, pentacarbonyl 1-methylbutylisonitrile, silane, or nitrous oxide. The second gas mixture is flowed into the process chamber100at a rate of about 1 sccm to about 10000 sccm, such as about 1 sccm to about 4000 sccm, such as about 1000 sccm to about 4000 sccm, such as about 2500 sccm.

In some exemplary embodiments which may be combined with other embodiments, the ramping of the second gas mixture flow into the process chamber100is about 10 sccm/s to 1000 sccm/s. In some embodiments, the flow rate of the first gas into the process chamber100is decreased by the same rate that the flow rate of the second gas mixture flow is increased. This enables the pressure within the process chamber100to be kept constant during the transition from the first gas to the second gas mixture flow.

In embodiments where the second gas mixture is a mixture of argon and propane, the ratio of argon gas to propane gas flown into the process chamber100may be between about 3:1 and about 10:1, such as about 4:1 and about 8:1, such as about 5:1 and about 7:1. In embodiments in which other precursor gases are used, a similar ratio of inert gas to reactant gas may be utilized.

In some embodiments which may be combined with other embodiments, operation310and operation312may be performed simultaneously, such that the second gas mixture is introduced while the pedestal104is moved to a new position.

Operation318is performed subsequent to operation316and prior to operation320. In operation318, the first gas mixture is flown into the process chamber100through the gas distributor112while the second gas mixture is removed from the process chamber100. By the end of operation318, the flow rates of both the first gas mixture and the second gas mixture are the same as the flow rates utilized in operation306. In some embodiments, the flow rate of the second gas mixture within the process chamber100may be about 0 sccm or near about 0 sccm by the end of operation318. The first gas mixture can flow at a rate of about 1 sccm to about 10,000 sccm, such as about 1 sccm to about 4000 sccm, such as about 1000 sccm to about 3000 sccm, such as about 2000 sccm by the end of operation318.

In optional operation320, the pedestal104is moved within the process chamber100to be at a third spacing, further from the gas distributor112than the second spacing. In some embodiments, the third spacing between the pedestal104and the gas distributor112is about 450 mils to about 750 mils, such as about 500 mils to about 700 mils, such as about 550 mils to about 650 mils, such as about 600 mils from the gas distributor112. Operation320may be performed subsequent to or simultaneously with operation318. Moving the pedestal104to the third spacing increases the breakdown potential required to arc DC plasma. By moving the pedestal104to a third spacing greater than the second spacing before operation320, the plasma creation within the process chamber100is halted or reduced before operation322and the application of RF power is ceased.

Operations302,304,306,308,310,312,314,316,318,320,322,324,326are described as being completed in sequence with one another in method300A and method300B. In alternative embodiments, several of the operations of method300A and method300B may be performed simultaneously. In some embodiments, operation310and operation312are performed simultaneously. In some exemplary embodiments, operation322and operation324are performed simultaneously.

Turning off the DC chucking voltage, supplied by the power source132, after turning off the RF power enables control of the position of the substrate107on the patterned surface142throughout operations302,304,306,308,310,312,314,316,318,310,322, and324. The position control helps stabilize the temperature of the substrate107relative to the patterned surface142, helping prevent backside damages caused by the shifting of the substrate107during processing. Additionally, after the RF power is turned off, the DC chucking voltage remains elevated at the DC chucking voltage described in operation316, which is sufficient to maintain the substrate107in position without discharging plasma. Another benefit of the methods described herein is the elapsed time to complete the process. One aspect of obtaining and maintaining thermal equilibrium is time. Position control is improved due to the chucking voltage being applied throughout operations304,306,308,310,312,314,316,318,320,322, and324. Improved position control allows for the substrate107to be chucked and acted upon by a heater for a longer period of time. The extended time allows for a relaxation of the substrate107around the posts210and prevents backside damages.

It is beneficial to control the position of the substrate107on the patterned surface142for the operations304-326. Previous attempts to chuck the substrate107before moving the substrate107to the second spacing results in DC based electrostatic discharge of the first gas. The electrostatic discharge of the first gas results in hardware damage and substrate defects. The methods presented herein prevent the electrostatic discharge of the first gas and allow for the substrate107to be chucked earlier in the method.

FIG.4is a graph400illustrating process parameter relations at operations within the methods disclosed herein. The graph400displays process conditions for spacing402between the pedestal104and the gas distributor112, pressure404within the process chamber100, flow rate of the first process gas406, flow rate of the carrier gas408, flow rate of the second process/deposition gas410, the applied DC chucking voltage412, and the applied RF power414during different times within the execution of the method described herein. The graph400displays process parameters for one embodiment of operations302,304,306,308,310,312,314,316,318,310,322,324, and326. However, other process configurations are contemplated.

The graph400is only one exemplary embodiment of how process parameters and relationships of each process parameter may be utilized. In other embodiments, each parameter may follow a different path over time. In some embodiments, the slope of each parameter may be greater or less than the slope of the parameters disclosed herein. In some embodiments, the operations302,304,306,308,310,312,314,316,318,310,322,324, and326may be rearranged slightly and some operations may be performed simultaneously that are not disclosed in the graph400.

The combination of the spacing, pressure, process gas, and chucking voltage utilized in the methods described herein allow for chucking of a substrate during the introduction and movement of the substrate. One or more combinations of these factors mitigates inadvertent plasma formation and electrostatic discharge adjacent to the substrate. Because inadvertent plasma formation and electrostatic discharge results in hardware damage and substrate defects, the methods herein provide improved processing over conventional methodologies. In aspects disclosed herein, spacing, pressure, gas composition, and/or the chucking voltage are controlled to prevent the process gas from arcing and inadvertently forming a plasma.

While the foregoing is directed to implementations of the present invention, other and further implementations of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.