Method for plasma processing over wide pressure range

A method for treating a substrate with plasma over a wide pressure range is described. The method comprises exposing the substrate to a low pressure plasma in a process chamber. Further, the method comprises exposing the substrate to a high pressure plasma in the process chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser. No. 11/871,865, entitled “Method and system for low pressure plasma processing”, filed on Oct. 12, 2007. The entire content of this application is herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method for performing plasma processing on a substrate and, more particularly, to a method for processing a substrate with a low pressure plasma and a high pressure plasma in the same plasma processing system.

2. Description of Related Art

During semiconductor processing, plasma is often utilized to assist etch processes by facilitating the anisotropic removal of material along fine lines or within vias (or contacts) patterned on a semiconductor substrate. Furthermore, plasma is utilized to enhance the deposition of thin films by providing improved mobility of adatoms on a semiconductor substrate.

For example, during dry plasma etching, a semiconductor substrate having an overlying patterned, protective layer, such as a photoresist layer, is positioned on a substrate holder in a plasma processing system. Once the substrate is positioned within the chamber, an ionizable, dissociative gas mixture is introduced, whereby the chemical composition is specially chosen for the specific material being etched on the semiconductor substrate. As the gas is introduced, excess gases are evacuated from the plasma processing system using a vacuum pump.

Thereafter, plasma is formed when a fraction of the gas species present are ionized by electrons heated via the transfer of radio frequency (RF) power either inductively or capacitively, or microwave power using, for example, electron cyclotron resonance (ECR). Moreover, the heated electrons serve to dissociate some species of the ambient gas species and create reactant specie(s) suitable for the exposed surface etch chemistry. Once the plasma is formed, selected surfaces of the substrate are etched by the plasma.

The process is adjusted to achieve appropriate conditions, including an appropriate concentration of desirable reactant and ion populations to etch various features (e.g., trenches, vias, contacts, etc.) in the selected regions of the substrate. Such substrate materials where etching is required include silicon dioxide (SiO2), low-k dielectric materials, poly-silicon, and silicon nitride.

The use of plasma (i.e., electrically charged particles), for example during etching, facilitates the anisotropic removal of material on the substrate in high aspect ratio features. Due to the charge of an ion or electron in the plasma, these particles may be effectively manipulated and guided using an electric field. In some applications where a high degree of anisotropy is required (e.g., polycrystalline silicon etching in front-end-of-line (FEOL) structures), low pressure processing may be required to limit the number of collisions between the directional flow of ions and the background gas. For instance, in an argon plasma, the ion-neutral mean free path is about 3 cm (centimeters) for a pressure of 1 mtorr (millitorr) and it is about 0.15 cm for a pressure of 20 mtorr. Therefore, low pressure processes (e.g., less than about 20 mtorr) may be more suitable for increased directionality for ions incident on the substrate and, hence, etch anisotropy. However, plasma formation and heating are more difficult for such low pressure processes.

SUMMARY OF THE INVENTION

The invention relates to a method for performing plasma processing on a substrate and, more particularly, to a method for processing a substrate with a low pressure plasma and a high pressure plasma in the same plasma processing system.

Furthermore, a method for treating a substrate with plasma over a wide pressure range is described. The method comprises exposing the substrate to a low pressure plasma in a process chamber. Further, the method comprises exposing the substrate to a high pressure plasma in the process chamber.

According to one embodiment, a method for treating a substrate with plasma over a wide pressure range is described. The method comprises disposing the substrate in a process chamber of a plasma processing system configured to treat the substrate with plasma, exposing the substrate to a low pressure plasma in the process chamber, and exposing the substrate to a high pressure plasma in the plasma processing system. The exposure of the substrate to the low pressure plasma comprises: creating a first plasma in a first plasma region of the plasma processing system at a pressure greater than about 10 mtorr; setting a pressure in a second plasma region of the process chamber less than about 10 mtorr; transporting electrons from the first plasma in the first plasma region to the second plasma region; heating the electrons in the second plasma region to form the low pressure plasma; and exposing the substrate to the low pressure plasma in the second plasma region. The exposure of the substrate to the high pressure plasma comprises: setting a pressure in the second plasma region of the process chamber greater than about 10 mtorr; forming the high pressure plasma in the second plasma region; and exposing the substrate to the high pressure plasma in the second plasma region.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following description, to facilitate a thorough understanding of the invention and for purposes of explanation and not limitation, specific details are set forth, such as a particular geometry of the plasma processing system and various descriptions of the system components. However, it should be understood that the invention may be practiced with other embodiments that depart from these specific details.

Nonetheless, it should be appreciated that, contained within the description are features which, notwithstanding the inventive nature of the general concepts being explained, are also of an inventive nature.

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,FIG. 1depicts a plasma processing system101comprising a plasma generation chamber105configured to produce a first plasma, and a process chamber110configured to provide a contaminant-free, vacuum environment for plasma processing of a substrate125. The process chamber110comprises a substrate holder120configured to support substrate125, and a vacuum pumping system130coupled to the process chamber110and configured to evacuate the process chamber110.

The plasma generation chamber105comprises a first plasma region142configured to receive a first process gas at a first pressure and form the first plasma. Furthermore, the process chamber110comprises a second plasma region152disposed downstream of the first plasma region142and configured to receive electrons150and the first process gas from the first plasma region142and form a second plasma therein at a second pressure.

A first gas injection system144is coupled to the plasma generation chamber105, and configured to introduce the first process gas to the first plasma region142. The first process gas may comprise an electropositive gas or an electronegative gas or a mixture thereof. For example, the first process gas may comprise a noble gas, such as Ar. Additionally, for example, the first process gas may comprise any gas suitable for treating substrate125. Furthermore, for example, the first process gas may comprise any gas having chemical constituents, atomic or molecular, suitable for treating substrate125. The first gas injection system144may include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, etc.

An optional second gas injection system154may be coupled to the process chamber110, and configured to introduce a second process gas to the second plasma region152. The second process gas may comprise any gas suitable for treating substrate125. Additionally, for example, the second process gas may comprise any gas having chemical constituents, atomic or molecular, suitable for treating substrate125. The second gas injection system may include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, etc.

Referring still toFIG. 1, the plasma processing system101comprises a plasma generation system140coupled to the plasma generation chamber105and configured to generate the first plasma in the first plasma region142. The plasma processing system101further comprises a plasma heating system180coupled to the process chamber110and configured to heat electrons150from the first plasma region142to form the second plasma in the second plasma region152.

The plasma generation system140can comprise a system configured to produce a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), a transformer coupled plasma (TCP), a surface wave plasma, a helicon wave plasma, or an electron cyclotron resonant (ECR) heated plasma, or other type of plasma understood by one skilled in the art of plasma formation.

For example, the plasma generation system140may comprise a first inductive coil148which is coupled to a first power source146. The first power source146may comprise a radio frequency (RF) generator that couples RF power through an optional impedance match network to first inductive coil148. RF power is inductively coupled from first inductive coil148through a dielectric window (not shown) to plasma in the first plasma region142. A typical frequency for the application of RF power to the inductive coil can range from about 10 MHz to about 100 MHz. In addition, a slotted Faraday shield (not shown) can be employed to reduce capacitive coupling between the first inductive coil148and plasma.

An impedance match network may serve to improve the transfer of RF power to plasma by reducing the reflected power. Match network topologies (e.g. L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

As illustrated inFIG. 1, the first inductive coil148may be a planar coil, such as a “spiral” coil or “pancake” coil, in communication with the plasma from above as in a transformer coupled plasma (TCP). Alternatively, as illustrated inFIG. 1, the first inductive coil may include a cylindrical coil, such as helical coil148′. The design and implementation of an ICP source, or TCP source, is well known to those skilled in the art.

As an example, in an electropositive discharge, the electron density may range from approximately 1010cm−3to 1013cm−3, and the electron temperature may range from about 1 eV to about 10 eV (depending on the type of plasma source utilized).

The plasma heating system180is configured to heat electrons150from the first plasma region142in the second plasma region152by utilizing capacitively coupled plasma (CCP) technology, inductively coupled plasma (ICP) technology, transformer coupled plasma (TCP) technology, surface wave plasma technology, helicon wave plasma technology, or electron cyclotron resonant (ECR) heated plasma technology, or other type of plasma technology understood by one skilled in the art of plasma formation.

For example, the plasma heating system180may comprise a second inductive coil188which is coupled to a second power source186. The second power source186may comprise a RF generator that couples RF power through an optional impedance match network to second inductive coil188. RF power is inductively coupled from second inductive coil188through a dielectric window (not shown) to plasma in the second plasma region152. A typical frequency for the application of RF power to the inductive coil can range from about 10 MHz to about 100 MHz. In addition, a slotted Faraday shield (not shown) can be employed to reduce capacitive coupling between the second inductive coil188and plasma.

An impedance match network may serve to improve the transfer of RF power to plasma by reducing the reflected power. Match network topologies (e.g. L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

Referring still toFIG. 1, a separation member170is disposed between the first plasma region142and the second plasma region152, wherein the separation member170comprises one or more openings172configured to allow passage of the first process gas as well as transport of electrons150from the first plasma in the first plasma region142to the second plasma region152in order to form the second plasma in the second plasma region152. The one or more openings172in the separation member170may comprise super-Debye length apertures, i.e., the transverse dimension or diameter is larger than the Debye length. The one or more openings172may be sufficiently large to permit adequate electron transport, and the one or more openings172may be sufficiently small to prevent or reduce electron heating across the separation member170. The one or more openings172may be sufficiently small to sustain a pressure difference between the first pressure in the first plasma region142and the second pressure in the second plasma region152.

As illustrated inFIG. 1, electrons150are transported from the first plasma region142to the second plasma region152through separation member170. The electron transport may be driven by diffusion, or it may be driven by field-enhanced diffusion. As electrons150emerge from the separation member170and enter the second plasma region152, they are heated by plasma heating system180.

In this configuration, where electrons150are fed from the first plasma region142to the second plasma region152and heated in the second plasma region152, the second pressure may be low relative to the first pressure in the first plasma region142. For example, the first pressure may be approximately an order of magnitude larger (e.g., 5 times greater (5×), 10×, 20×, 30×, etc.) than the second pressure. Additionally, for example, the first pressure may be selected for ease of plasma ignition and for efficient generation of plasma, while the second pressure is selected to be relatively low in order to reduce or minimize collisions in the second plasma region152.

Furthermore, for example, the first pressure may be greater than about 10 mtorr (millitorr), while the second pressure is less than about 10 mtorr. Alternatively, for example, the first pressure may be greater than about 20 mtorr, while the second pressure is less than about 10 mtorr. Alternatively, for example, the first pressure may be greater than about 50 mtorr, while the second pressure is less than about 10 mtorr. Alternatively, for example, the first pressure may be greater than about 10 mtorr, while the second pressure is less than about 5 mtorr. Alternatively, for example, the first pressure may be greater than about 10 mtorr, while the second pressure is less than about 1 mtorr. Alternatively yet, for example, the first pressure may be greater than about 50 mtorr, while the second pressure is less than about 5 mtorr.

Further yet, for example, the first pressure may range from about 10 mtorr to about 500 mtorr, e.g., about 20 mtorr to about 100 mtorr (e.g., 30 mtorr), while the second pressure may range from about 0.1 mtorr to about 10 mtorr, e.g., about 1 mtorr to about 10 mtorr (e.g., 3 mtorr).

Referring now toFIG. 2wherein like reference numerals designate identical or corresponding parts throughout the several views, a plasma processing system201is provided comprising a plasma generation chamber205configured to produce a first plasma, and a process chamber210configured to provide a contaminant-free, vacuum environment for plasma processing of a substrate225. The process chamber210comprises a substrate holder220configured to support substrate225, and a vacuum pumping system230coupled to the process chamber210and configured to evacuate the process chamber210.

The plasma generation chamber205comprises a first plasma region242configured to receive a first process gas at a first pressure and form the first plasma. Furthermore, the process chamber210comprises a second plasma region252disposed downstream of the first plasma region242and configured to receive the first process gas as well as electrons250from the first plasma region242and form a second plasma therein at a second pressure.

A first gas injection system244is coupled to the plasma generation chamber205, and configured to introduce the first process gas to the first plasma region242. The first process gas may comprise an electropositive gas or an electronegative gas or a mixture thereof. For example, the first process gas may comprise a noble gas, such as Ar. Additionally, for example, the first process gas may comprise any gas suitable for treating substrate225. Furthermore, for example, the first process gas may comprise any gas having chemical constituents, atomic or molecular, suitable for treating substrate225. The first gas injection system244may include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, etc.

An optional second gas injection system254may be coupled to the process chamber210, and configured to introduce a second process gas to the second plasma region252. The second process gas may comprise any gas suitable for treating substrate225. Additionally, for example, the second process gas may comprise any gas having chemical constituents, atomic or molecular, suitable for treating substrate225. The second gas injection system may include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, etc.

Referring still toFIG. 2, the plasma processing system201comprises a plasma generation system240coupled to the plasma generation chamber205and configured to generate the first plasma in the first plasma region242. The plasma processing system201further comprises a plasma heating system280coupled to the process chamber210and configured to heat electrons250from the first plasma region242to form the second plasma in the second plasma region252.

The plasma generation system240can comprise a system configured to produce a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), a transformer coupled plasma (TCP), a surface wave plasma, a helicon wave plasma, or an electron cyclotron resonant (ECR) heated plasma, or other type of plasma understood by one skilled in the art of plasma formation.

For example, the plasma generation system240may comprise a first inductive coil248which is coupled to a first power source246. The first power source246may comprise a radio frequency (RF) generator that couples RF power through an optional impedance match network to first inductive coil248. RF power is inductively coupled from first inductive coil248through a dielectric window (not shown) to plasma in the first plasma region242. A typical frequency for the application of RF power to the inductive coil can range from about 10 MHz to about 100 MHz. In addition, a slotted Faraday shield (not shown) can be employed to reduce capacitive coupling between the first inductive coil248and plasma.

An impedance match network may serve to improve the transfer of RF power to plasma by reducing the reflected power. Match network topologies (e.g. L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

As illustrated inFIG. 2, the first inductive coil248may be a cylindrical coil, such as helical coil. Alternatively, the first inductive coil may be a planar coil, such as “spiral” coil or “pancake” coil, in communication with the plasma from above as in a transformer coupled plasma (TCP). The design and implementation of an ICP source, or TCP source, is well known to those skilled in the art.

As an example, in an electropositive discharge, the electron density may range from approximately 1010cm−3to 1013cm−3, and the electron temperature may range from about 1 eV to about 10 eV (depending on the type of plasma source utilized).

The plasma heating system280is configured to heat electrons250from the first plasma region242in the second plasma region252by utilizing a transformer coupled plasma (TCP) source. The TCP source may comprise a second inductive coil288which is coupled to a second power source286. The second power source286may comprise a RF generator that couples RF power through an optional impedance match network to second inductive coil288. RF power is inductively coupled from second inductive coil288through a dielectric window270, formed in the ceiling of the process chamber210, to plasma in the second plasma region252. A typical frequency for the application of RF power to the inductive coil can range from about 10 MHz to about 100 MHz. In addition, a slotted Faraday shield (not shown) can be employed to reduce capacitive coupling between the second inductive coil288and plasma.

An impedance match network may serve to improve the transfer of RF power to plasma by reducing the reflected power. Match network topologies (e.g. L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

Referring still toFIG. 2, at least one opening272is formed through the dielectric window270in the ceiling of process chamber210that is disposed between the first plasma region242and the second plasma region252, wherein the at least one opening272in the ceiling of process chamber210is configured to allow passage of the first process gas as well as transport of electrons250from the first plasma in the first plasma region242to the second plasma region252in order to form the second plasma in the second plasma region252. The at least one opening272may comprise a super-Debye length aperture, i.e., the transverse dimension or diameter is larger than the Debye length. The at least one opening272may be sufficiently large to permit adequate electron transport. The at least one opening272may be sufficiently small to sustain a pressure difference between the first pressure in the first plasma region242and the second pressure in the second plasma region252.

As illustrated inFIG. 2, electrons250are transported from the first plasma region242to the second plasma region252through at least one opening272. The electron transport may be driven by diffusion, or it may be driven by field-enhanced diffusion. As electrons250emerge from the at least one opening272and enter the second plasma region252, they are heated by plasma heating system280.

In this configuration, where electrons250are fed from the first plasma region242to the second plasma region252and heated in the second plasma region252, the second pressure may be low relative to the first pressure in the first plasma region242. For example, the first pressure may be approximately an order of magnitude larger (e.g., 5 times greater (5×), 10×, 20×, 30×, etc.) than the second pressure. Additionally, for example, the first pressure may be selected for ease of plasma ignition and for efficient generation of plasma, while the second pressure is selected to be relatively low in order to reduce or minimize collisions in the second plasma region252.

Furthermore, for example, the first pressure may be greater than about 10 mtorr (millitorr), while the second pressure is less than about 10 mtorr. Alternatively, for example, the first pressure may be greater than about 20 mtorr, while the second pressure is less than about 10 mtorr. Alternatively, for example, the first pressure may be greater than about 50 mtorr, while the second pressure is less than about 10 mtorr. Alternatively, for example, the first pressure may be greater than about 10 mtorr, while the second pressure is less than about 5 mtorr. Alternatively, for example, the first pressure may be greater than about 10 mtorr, while the second pressure is less than about 1 mtorr. Alternatively yet, for example, the first pressure may be greater than about 50 mtorr, while the second pressure is less than about 5 mtorr.

Further yet, for example, the first pressure may range from about 10 mtorr to about 500 mtorr, e.g., about 20 mtorr to about 100 mtorr (e.g., 30 mtorr), while the second pressure may range from about 0.1 mtorr to about 10 mtorr, e.g., about 1 mtorr to about 10 mtorr (e.g., 3 mtorr).

Vacuum pumping system130(or 230) may, for example, include a turbo-molecular vacuum pump (TMP) capable of a pumping speed up to 5000 liters per second (and greater) and a vacuum valve (or second vacuum valve), such as a gate valve, for throttling the pressure in the second plasma region152or252. Furthermore, a device for monitoring chamber pressure (not shown) can be coupled to the process chamber110(or210). The pressure measuring device may be, for example, a Type 628B Baratron absolute capacitance manometer commercially available from MKS Instruments, Inc. (Andover, Mass.).

Referring toFIGS. 1 and 2, plasma processing system101(or 201) may comprise a substrate bias system coupled to substrate holder120(or220) and configured to electrically bias substrate125(or225). For example, the substrate holder120(or220) may include an electrode that is coupled to a RF generator through an optional impedance match network. A typical frequency for the application of power to the substrate holder120(or220) may range from about 0.1 MHz to about 100 MHz.

Referring still toFIGS. 1 and 2, plasma processing system101(or201) may comprise a substrate temperature control system coupled to the substrate holder120(or220) and configured to adjust and control the temperature of substrate125(or225). The substrate temperature control system comprises temperature control elements, such as a cooling system including a re-circulating coolant flow that receives heat from substrate holder120(or220) and transfers heat to a heat exchanger system (not shown), or when heating, transfers heat from the heat exchanger system. Additionally, the temperature control elements can include heating/cooling elements, such as resistive heating elements, or thermoelectric heaters/coolers, which can be included in the substrate holder120(or220), as well as the chamber wall of the process chamber110(or210) and any other component within the plasma processing system101(or201).

In order to improve the thermal transfer between substrate125(or225) and substrate holder120(or220), substrate holder120(or220) can include a mechanical clamping system, or an electrical clamping system, such as an electrostatic clamping system, to affix substrate125(or225) to an upper surface of substrate holder120(or220). Furthermore, substrate holder120(or220) can further include a substrate backside gas delivery system configured to introduce gas to the back-side of substrate125(or225) in order to improve the gas-gap thermal conductance between substrate125(or225) and substrate holder120(or220). Such a system can be utilized when temperature control of the substrate is required at elevated or reduced temperatures. For example, the substrate backside gas system can comprise a two-zone gas distribution system, wherein the helium gas gap pressure can be independently varied between the center and the edge of substrate225.

Referring still toFIGS. 1 and 2, plasma processing system101(or201) can further comprise a controller190(or290). Controller190(or290) comprises a microprocessor, memory, and a digital I/O port capable of generating control signals sufficient to communicate and activate inputs to plasma processing system101(or201) as well as monitor outputs from plasma processing system101(or201). Moreover, controller190(or290) can be coupled to and can exchange information with plasma generation system140(or240) including first gas injection system144(or244) and first power source146(or246), plasma heating system180(or280) including optional second gas injection system154(or254) and second power source186(or286), substrate holder120(or220), and vacuum pumping system130(or230). For example, a program stored in the memory can be utilized to activate the inputs to the aforementioned components of processing system101(or201) according to a process recipe in order to perform the method of treating substrate125(or225).

However, the controller190(or290) may be implemented as a general purpose computer system that performs a portion or all of the microprocessor based processing steps of the invention in response to a processor executing one or more sequences of one or more instructions contained in a memory. Such instructions may be read into the controller memory from another computer readable medium, such as a hard disk or a removable media drive. One or more processors in a multi-processing arrangement may also be employed as the controller microprocessor to execute the sequences of instructions contained in main memory. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.

The controller190(or290) includes at least one computer readable medium or memory, such as the controller memory, for holding instructions programmed according to the teachings of the invention and for containing data structures, tables, records, or other data that may be necessary to implement the present invention. Examples of computer readable media are compact discs, hard disks, floppy disks, tape, magneto-optical disks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM, SDRAM, or any other magnetic medium, compact discs (e.g., CD-ROM), or any other optical medium, punch cards, paper tape, or other physical medium with patterns of holes, a carrier wave (described below), or any other medium from which a computer can read.

The term “computer readable medium” as used herein refers to any medium that participates in providing instructions to the processor of the controller190(or290) for execution. A computer readable medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical, magnetic disks, and magneto-optical disks, such as the hard disk or the removable media drive. Volatile media includes dynamic memory, such as the main memory. Moreover, various forms of computer readable media may be involved in carrying out one or more sequences of one or more instructions to processor of controller for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions for implementing all or a portion of the present invention remotely into a dynamic memory and send the instructions over a network to the controller190(or290).

Controller190(or290) may be locally located relative to the processing system101(or201), or it may be remotely located relative to the processing system101(or201) via an internet or intranet. Thus, controller190(or290) can exchange data with the processing system101(or201) using at least one of a direct connection, an intranet, or the internet. Controller190(or290) may be coupled to an intranet at a customer site (i.e., a device maker, etc.), or coupled to an intranet at a vendor site (i.e., an equipment manufacturer). Furthermore, another computer (i.e., controller, server, etc.) can access controller190(or290) to exchange data via at least one of a direct connection, an intranet, or the internet.

Referring now toFIG. 3, a flow chart400is provided of a method for operating a plasma processing system to treat a substrate according to an embodiment of the invention. Flow chart400begins in410with disposing a substrate in a plasma processing chamber configured to facilitate the treatment of the substrate using plasma. The plasma processing chamber may include components of any one of the plasma processing systems described inFIGS. 1 and 2.

In420, a first plasma is formed from a first process gas in a first plasma region. As illustrated inFIGS. 1 and 2, the first plasma region may be located in a plasma generation chamber, and a plasma generation system may be coupled to the plasma generation chamber in order to form the first plasma.

In430, electrons from the first plasma in the first plasma region are transported or supplied to a second region disposed downstream of the first plasma region. As illustrated inFIGS. 1 and 2, the second plasma region may be located in a process chamber, wherein one or more openings or passages disposed between the plasma generation chamber and the process chamber facilitate the transport or supply of electrons from the first plasma region to the second plasma region.

In440, electrons that are supplied from the first plasma region to the second plasma region are heated by a plasma heating system. The electrons may be heated in the presence of the first process gas and an optional second process gas that may be introduced to the process chamber.

In450, gases entering the process chamber are pumped by a vacuum pumping system. In460, the substrate is exposed to the second plasma in the second plasma region.

Referring now toFIG. 4, a flow chart500is provided of a method for treating a substrate with plasma over a wide pressure range according to another embodiment. Flow chart500begins in510with disposing the substrate in a process chamber of a plasma processing system configured to treat the substrate with plasma. The plasma processing system may include the plasma processing system described inFIG. 1or2, or any combination thereof.

The plasma processing system ofFIG. 1andFIG. 2provides components that permit the formation of a high pressure plasma adjacent an upper surface of the substrate. Furthermore, the plasma processing system ofFIG. 1andFIG. 2also provides components that permit the formation of a low pressure plasma adjacent the upper surface of the substrate. For example, when forming a low pressure plasma adjacent the upper surface of the substrate, a high pressure plasma (formed at a pressure greater than or equal to 10 mtorr) may be formed remotely from the upper surface of the substrate and may be utilized to assist the formation of the low pressure plasma adjacent the upper surface of the substrate.

In520, the substrate is exposed to a low pressure plasma in the process chamber. The exposure of the substrate to the low pressure plasma comprises: creating a first plasma in a first plasma region of the plasma processing system at a pressure greater than about 10 mtorr; setting a pressure in a second plasma region of the process chamber less than about 10 mtorr; transporting electrons from the first plasma in the first plasma region to the second plasma region; heating the electrons in the second plasma region to form the low pressure plasma; and exposing the substrate to the low pressure plasma in the second plasma region. During low pressure plasma processing, the pressure in the second region may less than or equal to about 5 mtorr. Alternatively, during low pressure plasma processing, the pressure in the second region may less than or equal to about 1 mtorr.

Furthermore, during low pressure plasma processing, power from a first power source is coupled to the first plasma in the first plasma region during the creating of the first plasma, and power is coupled from a second power source to the low pressure plasma in the second plasma region during the heating of the low pressure plasma.

In530, the substrate is exposed to a high pressure plasma in the plasma processing system. The exposure of the substrate to the high pressure plasma comprises: setting a pressure in the second plasma region of the process chamber greater than about 10 mtorr; forming the high pressure plasma in the second plasma region; and exposing the substrate to the high pressure plasma in the second plasma region. During high pressure plasma processing, the pressure in the second region may greater than or equal to about 20 mtorr. Alternatively, during high pressure plasma processing, the pressure in the second region may greater than or equal to about 50 mtorr.

Furthermore, during high pressure plasma processing, power is coupled from the second power source to the high pressure plasma in the second plasma region during the forming of the high pressure plasma. Power from the first power source may not be coupled to the first plasma region, or power may be coupled to the first plasma region.

Although only certain embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.