Apparatus and method for improving photoresist properties using a quasi-neutral beam

The invention can provide apparatus and methods of processing a substrate in real-time using a Quasi-Neutral Beam (Q-NB) curing system to improve the etch resistance of photoresist layer. In addition, the improved photoresist layer can be used to more accurately control gate and/or spacer critical dimensions (CDs), to control gate and/or spacer CD uniformity, and to eliminate line edge roughness (LER) and line width roughness (LWR).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to substrate processing, and more particularly to improving the substrate processing using radiation-sensitive material (photoresist) curing and/or hardening procedures, and subsystems.

2. Description of the 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.

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.

However, the use of plasma (i.e., electrically charged particles), itself, produces problems in the manufacture of semiconductor devices. As devices have become smaller and integration densities have increased, breakdown voltages of insulation and isolation structures therein have, in many instances, been markedly reduced, often to much less than ten volts. For example, some integrated circuit (IC) device designs call for insulators of sub-micron thicknesses.

At the same time, the reduction of the size of structures reduces the capacitance value of the insulation or isolation structures, and relatively fewer charged particles are required to develop an electric field of sufficient strength to break down insulation or isolation structures. Therefore, the tolerance of semiconductor structures for the charge carried by particles impinging on them during the manufacturing process, such as a dry plasma etching process, has become quite limited and the structures for dissipating such charges during manufacture are sometimes required, often complicating the design of the semiconductor device.

While this problem could be avoided by performing processing with neutrally charged particles, the charge of an ion or electron is the only property by which the motion of these particles can be effectively manipulated and guided. Therefore, an ion must remain in a charged state until its trajectory can be established and the energy of the ion must be sufficient that its trajectory will remain unchanged when neutralized by an electron. Even then, the trajectory may be altered and the flux of a neutral beam can be severely depleted by collisions with other particles which may or may not have been neutralized and which may have trajectories that are not precisely parallel. As a result of this need, neutral beam sources have been developed to produce a beam of neutrally charged particles of arbitrary energy that may be as low as a few electron volts and as large as tens of thousands of electron volts or larger.

SUMMARY OF THE INVENTION

The invention relates to a method and system for treating a substrate and, more particularly, to an apparatus and method for improving the properties of an un-patterned and/or a patterned radiation-sensitive material (photoresist) layer using a Quasi-Neutral Beam (Q-NB) curing system.

Furthermore, the invention relates to a Q-NB curing system and methods for curing and/or hardening an un-patterned and/or a patterned radiation-sensitive material (photoresist) layer on a substrate with a space-charge neutralized quasi-neutral beam activated curing and/or hardening process. The Q-NB curing system comprises a first plasma chamber for forming a first plasma at a first plasma potential, and a curing (hardening) plasma chamber for forming a curing (hardening) plasma at a curing (hardening) plasma potential greater than the first plasma potential, wherein the curing (hardening) plasma is formed using electron flux from the first plasma. Further, the Q-NB curing (hardening) system comprises a substrate holder configured to position a substrate in the curing (hardening) plasma chamber.

The invention can include a Q-NB curing (hardening) system that comprises: a plasma generation chamber comprising a first plasma region configured to receive a first process gas at a first pressure; curing (hardening) chamber comprising a curing (hardening) plasma region disposed downstream of the first plasma region and configured to receive the first process gas from the first plasma region at a second pressure; a first gas injection system coupled to the plasma generation chamber and configured to introduce the first process gas to the first plasma region; a plasma generation system coupled to the plasma generation chamber and configured to generate a first plasma at a first plasma potential in the first plasma region from the first process gas; a separation member disposed between the first plasma region and the curing (hardening) plasma region, wherein the separation member comprises one or more openings configured to allow an electron flux from the first plasma region to the curing (hardening) plasma region to form a curing (hardening) plasma at a curing (hardening) plasma potential; a bias electrode system coupled to the curing (hardening) chamber and configured to elevate the curing (hardening) plasma potential above the first plasma potential in order to control the electron flux; a substrate holder coupled to the curing (hardening) chamber and configured to support the substrate proximate the curing (hardening) plasma region; and a vacuum pumping system coupled to the curing (hardening) chamber and configured to pump the curing (hardening) plasma region in the curing (hardening) chamber.

When electrons are fed from the first plasma region to the second plasma region and heated in the second plasma region, the second pressure may be low relative to the first pressure in the first plasma region. For example, the first pressure may be approximately an order of magnitude larger 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 region.

According to another embodiment, a method for curing and/or hardening an un-patterned and/or a patterned radiation-sensitive material (photoresist) layer on a substrate is described that comprises: disposing the substrate in a curing (hardening) chamber configured to cure and/or to harden an un-patterned and/or a patterned radiation-sensitive material (photoresist) layer; forming a first plasma in a first plasma region at a first plasma potential; forming a curing (hardening) plasma in a curing (hardening) plasma region at a curing (hardening) plasma potential using electron flux from the first plasma region; elevating the curing (hardening) plasma potential above the first plasma potential to control the electron flux; controlling a pressure in the curing (hardening) chamber; and exposing the substrate to the curing (hardening) plasma.

The invention can provide apparatus and methods of processing a substrate in real-time using subsystems and processing sequences created to cure and/or harden radiation-sensitive materials. In addition, the hardened radiation-sensitive layer can be used to more accurately control gate and/or spacer critical dimensions (CDs), to control gate and/or spacer CD uniformity, and to eliminate line edge roughness (LER) and line width roughness (LWR).

Other aspects of the invention will be made apparent from the description that follows and from the drawings appended hereto.

DETAILED DESCRIPTION

The invention provides apparatus and methods of processing a substrate in real-time using subsystems and processing sequences created to cure and/or harden radiation-sensitive materials. In addition, the cured and/or hardened radiation-sensitive material layer can be used to more accurately control gate and/or spacer critical dimensions (CDs), to control gate and/or spacer CD uniformity, and to eliminate and/or reduce line edge roughness (LER) and line width roughness (LWR).

In some embodiments, apparatus and methods are provided for creating and/or using a metrology library that includes profile data and diffraction signal data for cured and/or hardened radiation-sensitive material (photoresist) features and periodic structures.

One or more evaluation features can be provided at various locations on a substrate and can be used to evaluate and/or verify Q-NB curing (hardening) procedures and associated models. Substrates can have real-time and historical data associated with them, and the substrate data can include Q-NB curing and/or hardening data. In addition, the substrate can have other data associated with them, and the other data can include gate structure data, the number of required sites, the number of visited sites, confidence data and/or risk data for one or more of the sites, site ranking data, transferring sequence data, or process-related data, or evaluation/verification-related data, or any combination thereof. The data associated with substrates can include transfer sequence data that can be used to establish when and where to transfer the substrates, and transfer sequences can be changed using operational state data.

During radiation-sensitive material (photoresist) hardening and/or etching, a dry plasma process can be utilized, and the plasma is formed from a process gas by coupling electro-magnetic (EM) energy, such as radio frequency (RF) power, to the process gas in order to heat electrons and cause subsequent ionization and dissociation of the atomic and/or molecular composition of the process gas.

As feature sizes decrease below the 45 nm (nanometer) technology node, accurate processing and/or measurement data becomes more important and more difficult to obtain. Q-NB curing and/or hardening procedures can be used to more accurately process and/or measure these ultra-small devices and features. The data from a Q-NB curing and/or hardening procedure can be compared with the warning and/or control limits. When a run-rule is violated, an alarm can be generated indicating a processing problem, and correction procedures can be performed in real time.

FIG. 1shows an exemplary block diagram of a processing system in accordance with embodiments of the invention. In the illustrated embodiment, processing system100comprises a lithography subsystem110, a exposure subsystem120, an etch subsystem130, a deposition subsystem140, a Q-NB curing (hardening) subsystem150, an evaluation subsystem160, a transfer subsystem170, a manufacturing execution system (MES)180, a system controller190, and a memory/database195. Single subsystems (110,120,130,140,150,160, and170) are shown in the illustrated embodiment, but this is not required for the invention. In some embodiments, multiple subsystems (110,120,130,140,150,160, and170) can be used in a processing system100. In addition, one or more of the subsystems (110,120,130,140,150,160, and170) can comprise one or more processing elements that can be used in multi-layer processing sequences and associated curing and/or hardening procedures.

The system controller190can be coupled to the lithography subsystem110, the exposure subsystem120, the etch subsystem130, the deposition subsystem140, the Q-NB curing (hardening) subsystem150, the evaluation subsystem160, and the transfer subsystem170using a data transfer subsystem191. The system controller190can be coupled to the MES180using a first data transfer subsystem181. Alternatively, other configurations may be used. For example, the etch subsystem130, the deposition subsystem140, the Q-NB curing (hardening) subsystem150, the evaluation subsystem160, and a portion of the transfer subsystem170can be subsystems available from Tokyo Electron Limited.

The lithography subsystem110can comprise one or more transfer/storage elements112, one or more processing elements113, one or more controllers114, and one or more evaluation elements115. One or more of the transfer/storage elements112can be coupled to one or more of the processing elements113and/or to one or more of the evaluation elements115and can be coupled111to the transfer subsystem170. The transfer subsystem170can be coupled111to the lithography subsystem110, and one or more substrates105can be transferred via coupling111between the transfer subsystem170and the lithography subsystem110in real time. For example, the transfer subsystem170can be coupled to one or more of the transfer/storage elements112, to one or more of the processing elements113, and/or to one or more of the evaluation elements115. One or more of the controllers114can be coupled to one or more of the transfer/storage elements112, to the one or more of the processing elements113, and/or to one or more of the evaluation elements115.

In some embodiments, the lithography subsystem110can perform coating procedures, thermal procedures, measurement procedures, inspection procedures, alignment procedures, and/or storage procedures on one or more substrates. For example, one or more lithography-related processes can be used to deposit one or more masking layers that can include radiation-sensitive material (photoresist), and/or anti-reflective coating (ARC) material, and can be used to thermally process (bake) one or more of the masking layers. In addition, lithography subsystem110can be used to develop, measure, and/or inspect one or more of the patterned masking layers on one or more of the substrates.

The exposure subsystem120can comprise one or more transfer/storage elements122, one or more processing elements123, one or more controllers124, and one or more evaluation elements125. One or more of the transfer/storage elements122can be coupled to one or more of the processing elements123and/or to one or more of the evaluation elements125and can be coupled121to the transfer subsystem170. The transfer subsystem170can be coupled121to the exposure subsystem120, and one or more substrates105can be transferred via coupling121between the transfer subsystem170and the exposure subsystem120in real time. For example, the transfer subsystem170can be coupled to one or more of the transfer/storage elements122, to one or more of the processing elements123, and/or to one or more of the evaluation elements125. One or more of the controllers124can be coupled to one or more of the transfer/storage elements122, to the one or more of the processing elements123, and/or to one or more of the evaluation elements125.

In some embodiments, the exposure subsystem120can be used to perform wet and/or dry exposure procedures, and in other cases, the exposure subsystem120can be used to perform extreme ultraviolet (EUV) exposure procedures or e-beam writing procedures.

The etch subsystem130can comprise one or more transfer/storage elements132, one or more processing elements133, one or more controllers134, and one or more evaluation elements135. One or more of the transfer/storage elements132can be coupled to one or more of the processing elements133and/or to one or more of the evaluation elements135and can be coupled131to the transfer subsystem170. The transfer subsystem170can be coupled131to the etch subsystem130, and one or more substrates105can be transferred via coupling131between the transfer subsystem170and the etch subsystem130in real time. For example, the transfer subsystem170can be coupled to one or more of the transfer/storage elements132, to one or more of the processing elements133, and/or to one or more of the evaluation elements135. One or more of the controllers134can be coupled to one or more of the transfer/storage elements132, to the one or more of the processing elements133, and/or to one or more of the evaluation elements135. For example, one or more of the processing elements133can be used to perform plasma or non-plasma etching, ashing, and cleaning procedures, or plasma or non-plasma etching procedures. Evaluation procedures and/or inspection procedures can be used to measure and/or inspect one or more surfaces and/or layers of the substrates.

The deposition subsystem140can comprise one or more transfer/storage elements142, one or more processing elements143, one or more controllers144, and one or more evaluation elements145. One or more of the transfer/storage elements142can be coupled to one or more of the processing elements143and/or to one or more of the evaluation elements145and can be coupled141to the transfer subsystem170. The transfer subsystem170can be coupled141to the deposition subsystem140, and one or more substrates105can be transferred via coupling141between the transfer subsystem170and the deposition subsystem140in real time. For example, the transfer subsystem170can be coupled to one or more of the transfer/storage elements142, to one or more of the processing elements143, and/or to one or more of the evaluation elements145. One or more of the controllers144can be coupled to one or more of the transfer/storage elements142, to the one or more of the processing elements143, and/or to one or more of the evaluation elements145. For example, one or more of the processing elements143can be used to perform physical vapor deposition (PVD) procedures, chemical vapor deposition (CVD) procedures, ionized physical vapor deposition (iPVD) procedures, atomic layer deposition (ALD) procedures, plasma enhanced atomic layer deposition (PEALD) procedures, and/or plasma enhanced chemical vapor deposition (PECVD) procedures. Evaluation procedures and/or inspection procedures can be used to measure and/or inspect one or more surfaces of the substrates.

The Q-NB curing (hardening) subsystem150can comprise one or more transfer/storage elements152, one or more curing/hardening elements153, one or more controllers154, and one or more evaluation elements155. One or more of the transfer/storage elements152can be coupled to one or more of the curing/hardening elements153and/or to one or more of the evaluation elements155and can be coupled151to the transfer subsystem170. The transfer subsystem170can be coupled151to the Q-NB curing (hardening) subsystem150, and one or more substrates105can be transferred via coupling151between the transfer subsystem170and the Q-NB curing (hardening) subsystem150in real time. For example, the transfer subsystem170can be coupled to one or more of the transfer/storage elements152, to one or more of the curing/hardening elements153, and/or to one or more of the evaluation elements155. One or more of the controllers154can be coupled to one or more of the transfer/storage elements152, to the one or more of the curing/hardening elements153, and/or to one or more of the evaluation elements155.

The evaluation subsystem160can comprise one or more transfer/storage elements162, one or more measuring elements163, one or more controllers164, and one or more inspection elements165. One or more of the transfer/storage elements162can be coupled to one or more of the measuring elements163and/or to one or more of the inspection elements165and can be coupled161to the transfer subsystem170. The transfer subsystem170can be coupled161to the evaluation subsystem160, and one or more substrates105can be transferred via coupling161between the transfer subsystem170and the evaluation subsystem160in real time. For example, the transfer subsystem170can be coupled to one or more of the transfer/storage elements162, to one or more of the measuring elements163, and/or to one or more of the inspection elements165. One or more of the controllers164can be coupled to one or more of the transfer/storage elements162, to the one or more of the measuring elements163, and/or to one or more of the inspection elements165. The evaluation subsystem160can comprise one or more measuring elements163that can be used to perform real-time optical evaluation procedures that can be used to measure target structures at one or more sites on a substrate using library-based or regression-based techniques. For example, the sites on substrate105can include curing-related sites, target sites, overlay sites, alignment sites, measurement sites, verification sites, inspection sites, or damage-assessment sites, or any combination thereof. For example, one or more “golden substrates” or reference chips can be stored and used periodically to verify the performance of one or more of the measuring elements163, and/or one or more of the inspection elements165.

In some embodiments, the evaluation subsystem160can include integrated Optical Digital Profilometry (iODP) elements (not shown), and iODP elements/systems are available from Timbre Technologies Inc. (a TEL company). Alternatively, other metrology systems and/or inspection systems may be used. For example, iODP techniques can be used to obtain real-time data that can include critical dimension (CD) data, gate structure data, and thickness data, and the wavelength ranges for the iODP data can range from less than approximately 200 nm to greater than approximately 900 nm. Exemplary iODP elements can include ODP Profiler Library elements, Profiler Application Server (PAS) elements, and ODP Profiler Software elements. The ODP Profiler Library elements can comprise application specific database elements of optical spectra and its corresponding semiconductor profiles, CDs, and film thicknesses. The PAS elements can comprise at least one computer that connects with optical hardware and computer network. The PAS elements can be configured to provide the data communication, ODP library operation, measurement process, results generation, results analysis, and results output. The ODP Profiler Software elements can include the software installed on PAS elements to manage measurement recipe, ODP Profiler library elements, ODP Profiler data, ODP Profiler search/match results, ODP Profiler calculation/analysis results, data communication, and PAS interface to various metrology elements and computer network.

The evaluation subsystem160can use polarizing reflectometry, spectroscopic ellipsometry, reflectometry, or other optical measurement techniques to measure accurate device profiles, accurate CDs, and multiple layer film thickness of a substrate. The integrated metrology process (iODP) can be executed as an integrated process in an integrated group of subsystems. In addition, the integrated process eliminates the need to break the substrate for performing the analyses or waiting for long periods for data from external systems. IODP techniques can be used with the existing thin film metrology systems for inline profile and CD measurement, and can be integrated with TEL processing systems and/or lithography systems to provide real-time process monitoring and control. Simulated metrology data can be generated by applying Maxwell's equations and using a numerical analysis technique to solve Maxwell's equations.

The transfer subsystem170can comprise transfer elements174coupled to transfer tracks (175,176, and177) that can be used to receive substrates, transfer substrates, align substrates, store substrates, and/or delay substrates. For example, the transfer elements174can support two or more substrates. Alternatively, other transferring means may be used. The transfer subsystem170can load, transfer, store, and/or unload substrates based on a Q-NB curing and/or hardening procedure, a Q-NB curing-related processing sequence, a transfer sequence, operational states, the substrate and/or processing states, the processing time, the current time, the substrate data, the number of sites on the substrate, the type of sites on the substrates, the number of required sites, the number of completed sites, the number of remaining sites, or confidence data, or any combination thereof.

In some examples, transfer subsystem170can use loading data to determine where and when to transfer a substrate. In other examples, a transfer system can use Q-NB curing and/or hardening data to determine where and when to transfer a substrate. Alternatively, other procedures may be used. For example, when the first number of substrates is less than or equal to the first number of available processing elements, the first number of substrates can be transferred to the first number of available processing elements in the one or more of the subsystems using the transfer subsystem170. When the first number of substrates is greater than the first number of available processing elements, some of the substrates can be stored and/or delayed using one or more of the transfer/storage elements (112,122,132,142,152, and162) and/or the transfer subsystem170.

Operational state data can be established for the subsystems (110,120,130,140,150,160, and170) and can be used and/or updated by the Q-NB curing and/or hardening procedures. In addition, operational state data can be established for the transfer/storage elements (112,122,132,142,152, and162), elements (113,123,133,143,153, and163), and evaluation elements (115,125,135,145,155, and165), and can be updated by Q-NB curing and/or hardening procedures. For example, the operational state data for the processing elements can include availability data, matching data for the processing elements, expected processing times for some process steps and/or sites, yield data, confidence data and/or risk data for the processing elements, or confidence data and/or risk data for one or more curing and/or hardening procedures. Updated operational states can be obtained by querying in real-time one or more processing elements, and/or one or more subsystems. Updated loading data can be obtained by querying in real-time one or more transfer elements, and/or one or more transfer subsystems.

One or more of the controllers (114,124,134,144,154, and164) can be coupled to the system controller190and/or to each other using the data transfer subsystem191. Alternatively, other coupling configurations may be used. The controllers can be coupled in series and/or in parallel and can have one or more input ports and/or one or more output ports. For example, the controllers may include microprocessors having one or more core processing elements.

In addition, subsystems (110,120,130,140,150,160, and170) can be coupled to each other and to other devices using intranet, internet, wired, and/or wireless connections. The controllers (114,124,134,144, and190) can be coupled to external devices as required.

One or more of the controllers (114,124,134,144,154,164, and190) can be used when performing real-time Q-NB curing and/or hardening procedures. A controller can receive real-time data from a Q-NB curing and/or hardening model to update subsystem, processing element, process, recipe, profile, image, pattern, simulation, sequence data, and/or model data. One or more of the controllers (114,124,134,144,154,164, and190) can be used to exchange one or more Semiconductor Equipment Communications Standard (SECS) messages with the Manufacturing Execution Systems (MES)180or other systems (not shown), read and/or remove information, feed forward, and/or feedback the information, and/or send information as a SECS message. One or more of the formatted messages can be exchanged between controllers, and the controllers can process messages and extract new data in real-time. When new data is available, the new data can be used in real-time to update a model and/or procedure currently being used for the substrate and/or lot. For example, the current layout can be examined using the updated model and/or procedure when the model and/or procedure can be updated before the current layout is examined. The current layout can be examined using a non-updated model and/or procedure when an update cannot be performed before the current layout is processed. In addition, formatted messages can be used when resists are changed, when resist models are changed, when processing sequences are changed, when design rules are changed, or when layouts are changed.

In some examples, the MES180may be configured to monitor some subsystem and/or system processes in real-time, and factory level intervention and/or judgment rules can be used to determine which processes are monitored and which data can be used. For example, factory level intervention and/or judgment rules can be used to determine how to manage the data when a Q-NB curing and/or hardening error condition occurs. The MES180can also provide modeling data, processing sequence data, and/or substrate data.

In addition, controllers (114,124,134,144,154,164, and190) can include memory (not shown) as required. For example, the memory (not shown) can be used for storing information and instructions to be executed by the controllers, and may be used for storing temporary variables or other intermediate information during the execution of instructions by the various computers/processors in the processing system100. One or more of the controllers (114,124,134,144,154,164, and190), or other system components can comprise the means for reading data and/or instructions from a computer readable medium and can comprise the means for writing data and/or instructions to a computer readable medium.

The processing system100can perform a portion of or all of the processing steps of the invention in response to the computers/processors in the processing system executing one or more sequences of one or more instructions contained in a memory and/or received in a message. Such instructions may be received from another computer, a computer readable medium, or a network connection.

In some embodiments, an integrated system can be configured using system components from Tokyo Electron Limited (TEL), and external subsystems and/or tools may be included. For example, measurement elements can be provided that can include a CD-Scanning Electron Microscopy (CDSEM) system, a Transmission Electron Microscopy (TEM) system, a focused ion beam (FIB) system, an Optical Digital Profilometry (ODP) system, an Atomic Force Microscope (AFM) system, or another inspection system. The subsystems and/or processing elements can have different interface requirements, and the controllers can be configured to satisfy these different interface requirements.

One or more of the subsystems (110,120,130,140,150,160, and170) can perform control applications, Graphical User Interface (GUI) applications, and/or database applications. In addition, one or more of the subsystems (110,120,130,140,150,160, and170) and/or controllers (114,124,134,144,154,164, and190) can include Design of Experiment (DOE) applications, Advanced Process Control (APC) applications, Fault Detection and Classification (FDC) applications, and/or Run-to-Run (R2R) applications.

Output data and/or messages from Q-NB curing and/or hardening procedures can be used in subsequent procedures to optimize the process accuracy and precision. Data can be passed to Q-NB curing and/or hardening procedures in real-time as real-time variable parameters, overriding current model values, and reducing DOE tables. Real-time data can be used with a library-based system, or regression-based system, or any combination thereof to optimize a Q-NB curing and/or hardening procedure.

When a library-based process is used, the Q-NB curing and/or hardening data in the library can be generated and/or enhanced using Q-NB curing and/or hardening procedures, recipes, profiles, and/or models. For example, the Q-NB curing and/or hardening data in the library can include simulated and/or measured Q-NB curing and/or hardening data and corresponding sets of processing sequence data. The library-based processes can be performed in real-time. An alternative procedure for generating Q-NB curing and/or hardening data for a library can include using a machine learning system (MLS). For example, prior to generating the Q-NB curing and/or hardening data, the MLS can be trained using known input and output data, and the MLS may be trained with a subset of the Q-NB curing and/or hardening data.

Q-NB curing and/or hardening procedures can include intervention and/or judgment rules that can be executed whenever a matching context is encountered. Intervention and/or judgment rules and/or limits can be established based on historical procedures, on the customer's experience, or process knowledge, or obtained from a host computer. Rules can be used in Fault Detection and Classification (FDC) procedures to determine how to respond to alarm conditions, error conditions, fault conditions, and/or warning conditions. The rule-based FDC procedures can prioritize and/or classify faults, predict system performance, predict preventative maintenance schedules, decrease maintenance downtime, and extend the service life of consumable parts in the system. Various actions can take place in response to an alarm/fault, and the actions taken on the alarm/fault can be context-based, and the context data can be specified by a rule, a system/process recipe, a chamber type, identification number, load port number, cassette number, lot number, control job ID, process job ID, slot number and/or the type of data.

Unsuccessful Q-NB curing and/or hardening procedures can report a failure when one or more limits are exceeded, and successful procedures can create warning messages when limits are being approached. Pre-specified failure actions for procedures errors can be stored in a database, and can be retrieved from the database when an error occurs. For example, Q-NB curing and/or hardening procedures can reject the data at one or more of the sites for a substrate when a measurement procedure fails.

Q-NB curing and/or hardening procedures can be used to create, modify, and/or evaluate isolated and/or nested structures at different times and/or sites. For example, gate stack dimensions and substrate thickness data can be different near isolated and/or nested structures, and gate stack dimensions and substrate thickness data can be different near open areas and/or trench array areas. The hardened radiation-sensitive material (photoresist) features created by the Q-NB curing and/or hardening procedure can subsequently be used to create optimized features and/or structures for etched isolated and/or nested structures.

The Q-NB curing and/or hardening procedures can be used to reinforce the radiation-sensitive material (photoresist) film, supply optimum polymers, and suppress dissociation of the process gas. Therefore, the surface roughness of the radiation-sensitive material (photoresist) can be decreased. Further, the CD of an opening portion formed in the radiation-sensitive material (photoresist) film can be prevented from expanding, thereby realizing pattern formation with high accuracy. Particularly, these effects are more enhanced by controlling the DC voltage to suitably exercise the three functions described herein, i.e., the sputtering function, plasma optimizing function, and electron supply function.

The amount of by-products deposited during a Q-NB curing and/or hardening procedure depends on the potential difference between the plasma and the DC electrode, chamber wall, or the like.

FIG. 2Ashows a simplified block diagram of a Q-NB curing (hardening) subsystem in accordance with embodiments of the invention. In the illustrated embodiment shown inFIG. 2A, a Q-NB curing (hardening) subsystem200is described that is configured to cure and/or harden an un-patterned and/or a patterned radiation-sensitive material (photoresist) layer on a substrate with a space-charge neutralized quasi-neutral beam activated curing (hardening) process.

FIG. 2Billustrates conditions for a curing and/or hardening process to be performed in the Q-NB curing (hardening) subsystem depicted inFIG. 2A. A beam-electron floating potential (Vfe) is shown that exists because somewhere in the plasma there are insulator surfaces that are not under beam-electron bombardment; instead, these surfaces are under a Maxwellian thermal electron flux. The floating potential of these surfaces are the (Vfm) which is the “thermal Maxwellian floating potential”.

As illustrated inFIGS. 2A and 2B, the Q-NB curing (hardening) subsystem200can comprise a first plasma chamber210for forming a first plasma212at a first plasma potential (Vp,1), and a curing (hardening) plasma chamber220for forming a curing (hardening) plasma222at a curing (hardening) plasma potential (Vp,2) greater than the first plasma potential. The first plasma212is formed by coupling power, such as radio frequency (RF) power, to an ionizable gas in the first plasma chamber210, while the curing (hardening) plasma222is formed using electron flux (e.g., energetic electron (ee) current, jee) from the first plasma212. The RF power ranges from approximately 200 watts to approximately 20,000 watts. Further, the curing (hardening) plasma chamber211comprises a substrate holder configured to position a substrate225at a floating potential in the curing (hardening) plasma chamber220to be exposed to the curing (hardening) plasma222at the curing (hardening) plasma potential.

The first plasma chamber210comprises a plasma generation system216configured to ignite and heat the first plasma212. The first plasma212may be heated by any conventional plasma generation system including, but not limited to, an inductively coupled plasma (ICP) source, a transformer coupled plasma (TCP) source, a capacitively coupled plasma (CCP) source, an electron cyclotron resonance (ECR) source, a helicon wave source, a surface wave plasma source, a surface wave plasma source having a slotted plane antenna, etc. Although the first plasma212may be heated by any plasma source, it is desired that the first plasma212be heated by a method that produces a reduced or minimum fluctuation in its plasma potential (Vp,1). For example, an ICP source is a practical technique that produces a reduced or minimum (Vp,1) fluctuation.

Additionally, the first plasma chamber210comprises a direct current (DC) conductive ground electrode214having a conductive surface that acts as a boundary in contact with the first plasma212. The DC conductive ground electrode214is coupled to DC ground. The DC conductive ground electrode214acts as an ion sink that is driven by the first plasma212at the first plasma potential (Vp,1). Although one DC conductive ground electrode214is shown inFIG. 2A, the Q-NB curing (hardening) subsystem200may comprise one or more DC conductive ground electrodes.

Although not necessary, it is desirable that the DC conductive ground electrode214comprises a relatively large area in contact with the first plasma212. The larger the area at DC ground, the lower the first plasma potential. For example, the surface area of the conductive surface for the DC conductive ground electrode214in contact with the first plasma212may be greater than any other surface area in contact with the first plasma212. Additionally, for example, the surface area of the conductive surface for the DC conductive ground electrode214in contact with the first plasma212may be greater than the total sum of all other conductive surfaces that are in contact with the first plasma212. Alternatively, as an example, the conductive surface for the DC conductive ground electrode214in contact with the first plasma212may be the only conductive surface that is in contact with the first plasma212. The DC conductive ground electrode214may offer the lowest impedance path to ground.

As described above, (energetic) electron flux (or electron current jee) from the first plasma212initiates and sustains the curing (hardening) plasma222in the curing (hardening) plasma chamber220. In order to control the electron flux and produce a mono-energetic space-charge neutralized quasi-neutral beam, the first plasma potential (Vp,1), as described above, and the curing (hardening) plasma potential (Vp,2) should be stable with substantially reduced or minimal fluctuations if any fluctuations at all. To achieve this stability in the curing (hardening) plasma222, the curing (hardening) plasma chamber220comprises a DC conductive bias electrode224having a conductive surface in contact with the curing (hardening) plasma222, wherein the DC conductive bias electrode224is coupled to a DC power source226. The DC power source226is configured to bias the DC conductive bias electrode224at a positive DC voltage (+VDC). As a result, the curing (hardening) plasma potential (Vp,2) is a boundary-driven plasma potential driven by a (+VDC) voltage source, thus causing (Vp,2) to rise to about +VDC and remain substantially stable. Although one DC conductive bias electrode224is shown inFIG. 2A, the Q-NB curing (hardening) subsystem200may comprise one or more DC conductive bias electrodes.

Furthermore, the Q-NB curing (hardening) subsystem200comprises a separation member230disposed between the first plasma chamber210and the curing (hardening) plasma chamber220. The separation member230may act as an electron diffuser. The electron diffusion is driven by an electric field through an electron acceleration layer created by the potential difference ΔV={(Vp,2)−(Vp,1)}. The separation member230may comprise an insulator, such as quartz or alumina, or the separation member230may comprise a dielectric coated conductive material that is electrically floating and has high RF impedance to ground. Due to the large electric field across the electron acceleration layer ΔV={(Vp,2)−(Vp,1)}, the electron flux is sufficiently energetic to sustain ionization in the curing (hardening) plasma222. However, the Q-NB curing (hardening) subsystem200may optionally comprise a plasma heating system configured to further heat the curing (hardening) plasma222.

The separation member230may comprise one or more openings to permit the passage of the energetic electron flux from the first plasma chamber210to the curing (hardening) plasma chamber220. The total area of the one or more openings can be adjusted relative to the surface area of the DC conductive ground electrode214to ensure a relatively large potential difference ΔV={(Vp,2)−(Vp,1)} while minimizing reverse ion current from the curing (hardening) plasma222to the first plasma212, and thereby ensure a sufficient ion energy for ions striking the substrate225.

As illustrated inFIG. 2A, a first ion flux (e.g., ion current, ji1) from a first population of ions in the first plasma212flows to the DC conductive ground electrode214in the first plasma chamber210in a quantity approximately equivalent to the energetic electron flux (or electron current jee) from the first plasma212through the electron acceleration layer at the separation member230into the curing (hardening) plasma222, i.e., |ji1|˜|jee|.

As described above, the energetic electron flux is sufficiently energetic to form the curing (hardening) plasma222. Therein, a population of thermal electrons and a second population of ions are formed. The thermal electrons are largely a result of ejected electrons upon ionization of the curing (hardening) plasma222by the incoming energetic electron flux (or electron current jee). However, some energetic electrons from the energetic electron flux may lose a sufficient amount of energy and, thus, become part of the thermal electron population.

Due to Debye shielding, only the thermal electrons of the curing (hardening) plasma222flow to the DC conductive bias electrode224(e.g., thermal electron current, jte) in a quantity approximately equal to the energetic electron flux, i.e., |jte|˜|jee|. While thermal electron current jteis directed to the DC conductive bias electrode224, a second ion flux from the second population of ions is directed to the substrate at (Vp,2) (as ion current, ji2; which is approximately equivalent to the sum of the energetic current to the substrate225, jee, and the energetic electron generated secondary electron current (jese).

If the incoming energetic electron energy is sufficiently high, a substantial fraction of the energetic electron flux (jee) will survive the passage through the curing (hardening) plasma222and strike wafer225. However, regardless of their origin (i.e., energetic electrons from energetic electron flux jeeor energetic electrons from the thermal electron population), only energetic electrons capable of passing through the substrate sheath (i.e. climbing the potential “hill”, or {(Vfe)−(Vp,1}), wherein (Vfe) is the energetic electron floating potential) will reach substrate225. Since substrate225is at floating DC ground, the ion current ji2that is fed by the second ion population in the curing (hardening) plasma222(having ion energy characterized by {(Vp,2)−(Vfe)} will be equivalent to the electron current je2(i.e., no net current, or |ji2|˜|je2| or ji2+je2˜ji2+jee+jese˜0). Alternatively, the substrate225may be at approximately DC ground since the floating-ground surface potential is expected to be slightly above DC ground.

In such a configuration for the Q-NB curing (hardening) subsystem200, the elevation of the curing (hardening) plasma potential above the first plasma potential drives an energetic electron beam (having electron current jee) to form the curing (hardening) plasma222, while particle balance throughout the Q-NB curing (hardening) subsystem200enforces an equal number of electrons (e.g., electron current, je2) and ions (e.g., ion current, ji2) striking substrate225(i.e., |ji2|˜|je2|). This charge balance manifests as a space-charge neutralized quasi-neutral beam directed to substrate225that activates a curing (hardening) and/or hardening process at the substrate225.

FIG. 3shows an exemplary block diagram of a Quasi-Neutral Beam (Q-NB) curing (hardening) subsystem in accordance with embodiments of the invention.

In the illustrated embodiment, an exemplary Q-NB curing (hardening) system300is shown, and the exemplary Q-NB curing (hardening) system300can comprise a plasma generation chamber316that can be configured to produce a first plasma343at a first plasma potential, and a curing (hardening) chamber311that can be configured to provide a contaminant-free, vacuum environment for performing a Q-NB curing (hardening) procedure using a patterned substrate325. The Q-NB curing (hardening) subsystem310can include a substrate holder320configured to support the patterned substrate325, and a pressure control system335. In some examples, the pressure control system335can include a vacuum pump336and a gate valve337that can be coupled to the curing (hardening) chamber311and configured to evacuate the curing (hardening) chamber311and control a pressure in the curing (hardening) chamber311. Alternatively, the pressure control system335can be configured using a different number of pumps and/or a different number of flow control devices.

The plasma generation chamber316can include a first plasma region342that can be configured to receive a first process gas at a first pressure and can be configure to form first plasma343. The curing (hardening) chamber311can include a curing (hardening) plasma region352disposed downstream of the first plasma region342. The curing (hardening) chamber311can be configured to receive electron flux and one or more plasma species from the first plasma region342and form curing (hardening) plasma353therein at a curing (hardening) plasma potential and a second pressure. For example, the separation member370can include a plurality of openings372, and each of the openings372can be configured to create a beam350that can have a beam angle (φ). The beam angle (φ) can vary from approximately 80 degrees to approximately 89.5 degrees.

A first gas supply system345can be coupled to one or more first gas distribution elements347using at least one first supply line346. The first gas distribution element347can be configured within the plasma generation chamber316and can be used to introduce the first process gas to the first plasma region342. Alternatively, a different introduction method may be used. The first process gas can 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 argon (Ar). Additionally, for example, the first process gas may comprise any gas suitable for performing a Q-NB curing and/or hardening procedure using the patterned substrate325. In addition, the first process gas may comprise any gas having chemical constituents, atomic or molecular, suitable for performing a Q-NB curing and/or hardening procedure using the patterned substrate325. These chemical constituents may comprise etchants, film-forming gases, dilutants, cleaning gases, etc. The first gas supply system345can include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, one or more measurement devices, etc. The first supply line346and/or the first gas distribution element347can one or more control valves, one or more filters, one or more mass flow controllers, etc.

An optional curing (hardening) gas supply system355can be coupled to a curing (hardening) gas distribution element357using at least one second supply line356. The curing (hardening) gas distribution element357can be configured within the curing (hardening) chamber311and can be used to introduce at least one curing (hardening) gas to the curing (hardening) plasma region352. Alternatively, a different introduction method may be used. The curing (hardening) gas may comprise any gas suitable for performing a Q-NB curing (hardening) procedure using the patterned substrate325. Additionally, for example, the curing (hardening) gas may comprise any gas having chemical constituents, atomic or molecular, suitable for performing a Q-NB curing (hardening) procedure using the patterned substrate325. These chemical constituents may comprise etchants, film-forming gases, dilutants, cleaning gases, etc. The curing (hardening) gas supply system355may include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, one or more measurement devices, etc. The second supply line356and/or the curing (hardening) gas distribution element357can one or more control valves, one or more filters, one or more mass flow controllers, etc.

In various embodiments, the plasma species associated with the first gas supply system345can include Argon (Ar), CF4, F2, C4F8, CO, C5F8, C4F6, CHF3, N2/H2, or HBr, or any combination of two or more thereof. The plurality of first gas distribution elements347can provide different flow rates to different regions of the first plasma region342. In addition, the plasma species associated with the curing (hardening) gas supply system355can include Argon (Ar), CF4, F2, C4F8, CO, C5F8, C4F6, CHF3, N2/H2, or HBr, or any combination of two or more thereof. The plurality of curing (hardening) gas distribution elements357can provide different flow rates to different regions of the curing (hardening) plasma region352.

When the first process gas and or the curing (hardening) gas includes at least one fluorocarbon gas and at least one inert gas, a first fluorocarbon gas flow rate varying between approximately 10 sccm and approximately 50 sccm and a first inert gas flow rate varying between approximately 3 sccm and approximately 20 sccm, and the fluorocarbon gas comprises C4F6, C4F8, C5F8, CHF3, or CF4, or any combination thereof, and the inert gas comprises Argon (Ar), Helium (He), Krypton (Kr), Neon (Ne), Radon (Rn), or Xenon (Xe), or any combination thereof.

When the first process gas and or the curing (hardening) gas includes CO, the CO flow rate can vary between approximately 2 sccm and approximately 20 sccm.

In addition, the exemplary Q-NB curing (hardening) system300can comprise a power source360and a first multi-turn inductive coil362that can be coupled to the power source360. The power source360may comprise a radio frequency (RF) generator that couples RF power through an impedance match network361to the first multi-turn inductive coil362. For example, the RF power from the power source360can range from approximately 200 watts to approximately 10000 watts. RF power is inductively coupled from the first multi-turn inductive coil362through a dielectric window363to the first plasma343in the first plasma region342. The impedance match network361can be used to improve the transfer of RF power to plasma by reducing the reflected power. Match network topologies (e.g. L-type, u-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

A typical frequency for the application of RF power to the first multi-turn inductive coil362can range from about 10 MHz to about 100 MHz. In addition, a slotted Faraday shield364can be employed to reduce capacitive coupling between the first multi-turn inductive coil362and plasma. Although the first plasma may be heated by any plasma source, it is desired that the first plasma be heated by a method, as previously shown inFIG. 2AandFIG. 2B, that produces a minimum fluctuation in its plasma potential (Vp,1).

In alternate embodiments, a different plasma generation system (not shown) can be coupled to the plasma generation chamber316and configured to generate the first plasma343in the first plasma region342. The different plasma generation system may include 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. In addition, any ICP source can be used that produces a reduced or minimum (Vp,1) fluctuation.

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).

Still referring toFIG. 3, the plasma generation subsystem315can include a plasma generation chamber316that can include a direct current (DC) conductive electrode317having a conductive surface that acts as a boundary in contact with the first plasma343. The DC conductive ground electrode317is coupled to DC ground. For example, the DC conductive ground electrode317may comprise a doped silicon electrode. The DC conductive ground electrode317acts as an ion sink that is driven by the first plasma343at the first plasma potential (Vp,1). Although a single DC conductive ground electrode317is shown inFIG. 3, the Q-NB curing (hardening) system300may comprise one or more DC conductive ground electrodes.

Although not necessary, it is desirable that the DC conductive ground electrode317comprises a relatively large area in contact with the first plasma343. The larger the area at DC ground, the lower the first plasma potential. For example, the surface area of the conductive surface for the DC conductive ground electrode317in contact with the first plasma343may be greater than any other surface area in contact with the first plasma343. Additionally, for example, the surface area of the conductive surface for the DC conductive ground electrode317in contact with the first plasma343may be greater than the total sum of all other conductive surfaces that are in contact with the first plasma343. Alternatively, as an example, the conductive surface for the DC conductive ground electrode317in contact with the first plasma343may be the only conductive surface that is in contact with the first plasma343. The DC conductive ground electrode317may offer the lowest impedance path to ground.

In addition, the Q-NB curing (hardening) subsystem310can comprise a bias electrode system380coupled to the curing (hardening) chamber311. The bias electrode system380can be configured to elevate the curing (hardening) plasma potential to a value above the first plasma potential in order to drive the electron flux in the correct direction. The bias electrode system380can include one or more DC conductive bias electrodes382that have at least one conductive surface in contact with the curing (hardening) plasma353. The DC conductive bias electrode382can be electrically insulated from the curing (hardening) chamber311using at least one insulator384and the DC conductive bias electrode382is coupled to a DC power source385. The conductive bias electrode382is composed of a conductive material, such as metal or doped silicon. In addition, one or more electrical supply elements383can be configured to allow electrical connection to the DC conductive bias electrode382.

Although a single DC conductive bias electrode382is shown inFIG. 3, the Q-NB curing (hardening) subsystem310can comprise one or more DC conductive bias electrodes.

Although not necessary, it is desirable that the DC conductive bias electrode382comprises a relatively large area in contact with the curing (hardening) plasma353. The larger the area at the +VDC potential, the closer the curing (hardening) plasma potential will be to +VDC. As an example, the total area of the DC conductive bias electrode382may be greater than the total sum of all other conductive surfaces that are in contact with the curing (hardening) plasma353. Alternatively, as an example, the total area of the DC conductive bias electrode382may be the only conductive surface that is in contact with the curing (hardening) plasma353.

The DC power source385can include a variable DC power supply. Additionally, the DC power source385can include a bipolar DC power supply. The DC power source385can further include a system configured to perform at least one of monitoring adjusting, or controlling the polarity, current, voltage, or on/off state of the DC power source385. An electrical filter may be utilized to de-couple RF power from the DC power source385.

For example, the DC voltage applied to the DC conductive bias electrode382by DC power source385may range from approximately 0 volts (V) to approximately 10000 V. Desirably, the DC voltage applied to the DC conductive bias electrode382by DC power source385may range from approximately 50 volts (V) to approximately 5000 V. Additionally, it is desirable that the DC voltage has a positive polarity. Furthermore, it is desirable that the DC voltage is a positive voltage having an absolute value greater than approximately 50 V.

As shown inFIG. 3, the curing (hardening) chamber311can include one or more chamber housing members that may be coupled to ground. Additionally, a liner member381can be disposed between one or more of the walls of the curing (hardening) chamber311and the curing (hardening) plasma353. For example, each liner member381can be fabricated from a dielectric material, such as quartz or alumina, and the liner member381can provide a high RF impedance to ground for the curing (hardening) plasma353.

In addition, the Q-NB curing (hardening) system300can include at least one separation member370that can be configured between the first plasma region342and the curing (hardening) plasma region352. The separation member370can include one or more openings372that can be configured to create a plurality of beams350that can include at least one plasma species as well as an electron flux from the first plasma343in the first plasma region342to the curing (hardening) plasma region352. For example, the electrons and/or ions in the plurality of beams350can be used to form the curing (hardening) plasma353in the curing (hardening) plasma region352.

One or more of the openings372in the separation member370can comprise a super-Debye length apertures, i.e., the transverse dimension or diameter is larger than the Debye length. The openings372can be sufficiently large to permit adequate electron transport, and the openings372may be sufficiently small to allow a sufficiently high potential difference between the first plasma potential and the curing (hardening) plasma potential and to reduce any reverse ion current between the curing (hardening) plasma353and the first plasma343. Further, the one or more openings372may be sufficiently small to sustain a pressure difference between the first pressure in the first plasma region342and the second pressure in the curing (hardening) plasma region352.

Although the DC conductive ground electrode317is coupled to DC ground, it may be coupled to a DC voltage less than the bias DC voltage coupled to the DC conductive bias electrode382.

As illustrated inFIG. 3, the plurality of beams350can include an electron flux that occurs between the first plasma region342and the curing (hardening) plasma region352through separation member370. The electron transport is driven by electric field-enhanced diffusion, wherein the electric field is established by the potential difference between the first plasma potential and the curing (hardening) plasma potential. The plurality of beams350can include an electron flux that can be sufficiently energetic to sustain ionization in the curing (hardening) plasma353.

Pressure control system335can include a pump336that can be a turbo-molecular vacuum pump (TMP) capable of a pumping speed up to 5000 liters per second (and greater) and a vacuum valve337(or second vacuum valve), such as a gate valve, for controlling the pressure in the curing (hardening) plasma region352. Furthermore, one or more sensors339for monitoring chamber conditions can be coupled to the curing (hardening) chamber311, and one or more of the sensors339can be used to measure pressure in the curing (hardening) chamber311.

In some embodiments, the Q-NB curing (hardening) subsystem310can include a substrate holder320that can be coupled to ground. If the substrate holder320is coupled to ground, the patterned substrate325can be at floating ground and, therefore, the only ground the curing (hardening) plasma353contacts is the floating ground provided by patterned substrate325. For example, when the patterned substrate325is clamped to substrate holder320, a ceramic electrostatic clamp (ESC) layer may insulate the patterned substrate325from the grounded substrate holder320.

Referring still toFIG. 3, the Q-NB curing (hardening) subsystem310can include a substrate temperature control system328coupled to the substrate holder320and configured to adjust and control the temperature of patterned substrate325. The substrate temperature control system328can include temperature control elements329in the substrate holder320that can be used to control the temperature of the patterned substrate325. Alternatively, the temperature control elements (not shown) may be configured in the chamber wall of the curing (hardening) chamber311and any other component within the Q-NB curing (hardening) subsystem310.

In order to improve the thermal transfer between the patterned substrate325and substrate holder320, the substrate holder320can include electrostatic clamping (ESC) electrode323that can be coupled to a clamping supply322to affix the patterned substrate325to an upper surface of substrate holder320. In some embodiments, the electrostatic clamping (ESC) electrode323can be used to isolate the patterned substrate325from the grounded substrate holder320.

Furthermore, substrate holder320can further include backside gas elements327that can be coupled to a backside gas delivery system326that can be configured to introduce gas to the backside of the patterned substrate325in order to improve the gas-gap thermal conductance between the patterned substrate325and substrate holder320. Such a system can be utilized when temperature control of the patterned substrate325is required at elevated or reduced temperatures. For example, the substrate backside gas delivery system326can be coupled to a two-zone (center/edge) backside gas elements327, wherein the helium gas gap pressure can be independently varied between the center and the edge of the patterned substrate325. In other embodiments, the backside gas elements327can be used to isolate the patterned substrate325from the grounded substrate holder320.

In addition, the substrate holder320may be surrounded by a baffle member321that extends beyond a peripheral edge of the substrate holder320. The baffle member321may serve to homogeneously distribute the pumping speed delivered by the pressure control system335to the curing (hardening) plasma region352. The baffle member321may be fabricated from a dielectric material, such as quartz, or alumina. The baffle member321may provide a high RF impedance to ground for the curing (hardening) plasma353.

A transfer port301for a semiconductor substrate is formed in the sidewall of the curing (hardening) chamber311, and can be opened/closed by a gate valve302attached thereon. One or more of the controllers395can be coupled to gate valve302and can be configured to control gate valve302. The patterned substrate325can be, for example, transferred into and out of curing (hardening) chamber311through transfer port301and gate valve302from a transfer subsystem (170,FIG. 1), and it can be received by substrate lift pins (not shown) housed within substrate holder320and mechanically translated by devices (not show) housed therein. After the patterned substrate325is received from transfer system, it can be lowered to an upper surface of substrate holder320. The design and implementation of substrate lift pins is well known to those skilled in the art. Alternatively, an un-patterned substrate may be used.

In some embodiments, a conductive focus ring306can be used, and the conductive focus ring306can include a silicon-containing material and can be disposed on the top of the substrate holder320. In some examples, conductive focus ring306can be configured to surround the electrostatic electrode323, the backside gas elements327, and the patterned substrate325to improve uniformity at the edge of the substrate. In other examples, the conductive focus ring306can include a correction ring portion (not shown) that can be used to modify the edge temperature of the patterned substrates325. Alternatively, a non-conductive focus ring may be used.

In other embodiments, an inner deposition shield308can be detachably coupled to the substrate holder320to prevent by-products created during curing (hardening) procedures from being deposited on the substrate holder320. In addition, an outer deposition shield (not shown) can be detachably coupled along one or more of the inner walls of the curing (hardening) chamber311to prevent by-products created during curing (hardening) procedures from being deposited on the wall. For example, the outer deposition shield can be configured as a part of a chamber wall. The baffle member321and the deposition shield308can include an aluminum body covered with a ceramic, such as Y2O3. The gate valve337can be coupled to an exhaust space formed at the bottom of the curing (hardening) chamber311.

As depicted inFIG. 3, the Q-NB curing (hardening) subsystem310can include one or more first process sensors338coupled to the first plasma region342and one or more second process sensors339coupled to the curing (hardening) plasma region352. Alternatively, the number and position of the process sensors (338,339) may be different. In various embodiments, the first process sensors338can include one or more optical devices for monitoring the light emitted from the first plasma343in the first plasma region342, and the second process sensors339can include one or more optical devices for monitoring the light emitted from the curing (hardening) plasma353in the curing (hardening) plasma region352. For example, one or more Optical Emission Spectroscopy (OES) sensors may be used, and the OES data can be used as ignition data, operational data, or endpoint data.

One or more of the process sensors (338,339) can include gas-sensing devices for monitoring and/or controlling input gasses, process gasses, and/or exhaust gasses. In addition, the one or more of the process sensors (338,339) can include pressure sensors, temperature sensors, current and/or voltage probes, power meters, spectrum analyzers, or an RF Impedance analyzer, or any combination thereof.

In addition, the Q-NB curing (hardening) subsystem310can include one or more internal sensors (not shown), and the internal sensors can include those sensors pertaining to the functionality of curing (hardening) chamber311, such as the measurement of the Helium backside gas pressure, Helium backside flow, electrostatic clamping (ESC) voltage, ESC current, substrate holder temperature (or lower electrode (LEL) temperature), coolant temperature, DC conductive bias electrode temperature, DC bias, forward RF power, reflected RF power, RF peak-to-peak voltage, chamber wall temperature, process gas flow rates, process gas partial pressures, matching network settings, a focus ring thickness, RF hours, focus ring RF hours, and any statistic thereof.

Controller395can include one or more microprocessors, one or more memory elements, and one or more analog and/or digital I/O devices (potentially including D/A and/or ND converters) capable of generating control voltages sufficient to communicate and activate inputs to the Q-NB curing (hardening) system300as well as monitor outputs from Q-NB curing (hardening) system300. As shown inFIG. 3, controller395can be coupled to and exchange information with gate valve302, a clamping supply322, backside gas delivery system326, temperature control system328, sensors339, first gas supply system345, curing (hardening) gas supply system355, pressure control system335, power source360, and DC power source385. One or more programs stored in the memory can be utilized to interact with the aforementioned components of the Q-NB curing (hardening) system300according to stored process recipes.

The plurality of controllers395may 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 controller/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 control 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.

When a curing (hardening) process is performed by the Q-NB curing (hardening) system300, the gate valve302can be opened, and a patterned substrate325to be cured is transferred into the curing (hardening) chamber311and placed on the substrate holder320. The plasma generation subsystem315can provide a first plasma species and the curing (hardening) chamber311can be configured to use a first plasma species to facilitate the generation of curing (hardening) plasma353in curing (hardening) plasma region352adjacent a surface of the patterned substrate325. The curing (hardening) plasma species can include a fluorocarbon element (CxFy), such as C4F8, and may contain another component, such as Ar, or CO. The flow rate for the first plasma species (ions) and/or electrons can be established using the curing (hardening) recipe. In addition, an ionizable curing (hardening) gas or mixture of curing (hardening) gases can introduced from the curing (hardening) gas supply system355, and process pressure can be adjusted using pressure control system335. For example, the pressure inside plasma generation chamber316can range from about 1 mtorr (millitorr) to about 1200 mtorr, and the pressure inside the curing (hardening) chamber311can range between about 0.1 mtorr and about 150 mtorr. In other examples, the pressure inside plasma generation chamber316can range from about 10 mtorr to about 150 mtorr, and the pressure inside the curing (hardening) chamber311can range between about 1 mtorr and about 15 mtorr.

In some other embodiments, while the first plasma species and the curing (hardening) gas is supplied into the curing (hardening) chamber311, a controllable DC voltage can be applied from the DC power source385to the DC conductive bias electrode382. Furthermore, another DC voltage can be applied from the clamping supply322to the electrostatic electrode323to fix the semiconductor substrate on the substrate holder320. Radicals and ions generated in the curing (hardening) plasma353are used to cure the radiation-sensitive material (photoresist) layer on the patterned substrate325.

When the radiation-sensitive material (photoresist) film on the patterned substrate325is an ArF resist film, the ArF resist film changes its polymer structure when it is radiated with electrons. When the composition of the ArF resist film is reformed due to the resist cross-linkage reaction, the etching resistance property of the ArF resist film increases. In addition, the surface roughness of the ArF resist film is decreased. Therefore, the applied power from the power source360and DC power source385can be controlled by the controller395to enhance the etching resistance property of the radiation-sensitive material (photoresist) film (particularly, ArF resist film) by irradiation with electrons.

One or more of the process sensors339may be disposed to detect the plasma state, so that the controller395can control the flow rate for the first plasma species and the other radiation-sensitive material (photoresist) curing (hardening) recipe parameters using the detected plasma state. For example, the DC power source385can be independently controlled when it is applied to the DC conductive bias electrode382. In addition, one or more sensors339may be used to measure the plasma sheath length or the electron density.

FIG. 4shows an exemplary block diagram of an additional Quasi-Neutral Beam (Q-NB) curing (hardening) subsystem in accordance with embodiments of the invention.

In the illustrated embodiment, an exemplary Q-NB curing (hardening) system400is shown, and the exemplary Q-NB curing (hardening) system400can comprise a plasma generation chamber416that can be configured to produce an upper plasma443at a first plasma potential, and a curing (hardening) chamber411that can be configured to provide a contaminant-free, vacuum environment for performing a Q-NB curing and/or hardening procedure using a patterned substrate425. The Q-NB curing (hardening) subsystem410can include a substrate holder420configured to support the patterned substrate425, and a pressure control system435. In some examples, the pressure control system435can include a vacuum pump436and a gate valve437that can be coupled to the curing (hardening) chamber411and configured to evacuate the curing (hardening) chamber411and control a pressure in the curing (hardening) chamber411. Alternatively, the pressure control system435can be configured using a different number of pumps and/or a different number of flow control devices.

The plasma generation chamber416can include an upper plasma region442that can be configured to receive a first process gas at a first pressure and can be configure to form an upper plasma443. The curing (hardening) chamber411can include a curing (hardening) plasma region452disposed downstream of the upper plasma region442. The curing (hardening) chamber411can be configured to receive electron flux and one or more plasma species from the upper plasma region442and form curing (hardening) plasma453therein at a curing (hardening) plasma potential and a second pressure. For example, the separation member470can include a plurality of openings472, and each of the openings472can be configured to create a beam450that can have a beam angle (φ). The beam angle (φ) can vary from approximately 80 degrees to approximately 89.5 degrees.

A first gas injection system445can be coupled to one or more first gas distribution elements447using at least one first supply line446. The first gas distribution element447can be configured within the plasma generation chamber416and can be used to introduce the first process gas to the upper plasma region442. Alternatively, a different introduction method may be used. The first process gas can 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 argon (Ar). Additionally, for example, the first process gas may comprise any gas suitable for performing a Q-NB curing and/or hardening procedure using the patterned substrate425. In addition, the first process gas may comprise any gas having chemical constituents, atomic or molecular, suitable for performing a Q-NB curing and/or hardening procedure using the patterned substrate425. These chemical constituents may comprise etchants, film-forming gases, dilutants, cleaning gases, etc. The first gas injection system445can include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, one or more measurement devices, etc. The first supply line446and/or the first gas distribution element447can one or more control valves, one or more filters, one or more mass flow controllers, etc.

An optional curing (hardening) gas supply system455can be coupled to a curing (hardening) gas distribution element457using at least one second supply line456. The curing (hardening) gas distribution element457can be configured within the curing (hardening) chamber411and can be used to introduce at least one curing (hardening) gas to the curing (hardening) plasma region452. Alternatively, a different introduction method may be used. The curing (hardening) gas may comprise any gas suitable for performing a Q-NB curing and/or hardening procedure using the patterned substrate425. Additionally, for example, the curing (hardening) gas may comprise any gas having chemical constituents, atomic or molecular, suitable for performing a Q-NB curing and/or hardening procedure using the patterned substrate425. These chemical constituents may comprise etchants, film-forming gases, dilutants, cleaning gases, etc. The curing (hardening) gas supply system455may include one or more gas supplies or gas sources, one or more control valves, one or more filters, one or more mass flow controllers, one or more measurement devices, etc. The second supply line456and/or the curing (hardening) gas distribution element457can one or more control valves, one or more filters, one or more mass flow controllers, etc.

In various embodiments, the plasma species associated with the first gas injection system445can include Argon (Ar), CF4, F2, C4F8, CO, C5F8, C4F6, CHF3, N2/H2, or HBr, or any combination of two or more thereof. The plurality of first gas distribution elements447can provide different flow rates to different regions of the upper plasma region442. In addition, the plasma species associated with the curing (hardening) gas supply system455can include Argon (Ar), CF4, F2, C4F8, CO, C5F8, C4F6, CHF3, N2/H2, or HBr, or any combination of two or more thereof. The plurality of curing (hardening) gas distribution elements457can provide different flow rates to different regions of the curing (hardening) plasma region452.

When the first process gas and or the curing (hardening) gas includes at least one fluorocarbon gas and at least one inert gas, a first fluorocarbon gas flow rate varying between approximately 10 sccm and approximately 50 sccm and a first inert gas flow rate varying between approximately 3 sccm and approximately 20 sccm, and the fluorocarbon gas comprises C4F6, C4F8, C5F8, CHF3, or CF4, or any combination thereof, and the inert gas comprises Argon (Ar), Helium (He), Krypton (Kr), Neon (Ne), Radon (Rn), or Xenon (Xe), or any combination thereof.

When the first process gas and or the curing (hardening) gas includes CO, the CO flow rate can vary between approximately 2 sccm and approximately 20 sccm.

In addition, the exemplary Q-NB curing (hardening) system400can comprise a RF power source460and at least one multi-turn inductive coil462that can be mounted above the upper plasma region442. The RF power source460can include a radio frequency (RF) generator that couples RF power through an impedance match network461to the at least one multi-turn inductive coil462. For example, the RF power from the RF power source460can range from approximately 200 watts to approximately 10000 watts. RF power is inductively coupled from the multi-turn inductive coil462through a dielectric window463to the upper plasma443in the upper plasma region442. The impedance match network461can be used to improve the transfer of RF power to plasma by reducing the reflected power. Match network topologies (e.g. L-type, u-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

In various embodiments, the frequency for the application of RF power to the multi-turn inductive coil462can range from about 10 MHz to about 100 MHz. In addition, a slotted Faraday shield464can be employed to reduce capacitive coupling between the multi-turn inductive coil462and plasma. Although the upper plasma may be heated by any plasma source, it is desired that the upper plasma be heated by a method, as previously shown inFIG. 2AandFIG. 2B, that produces a minimum fluctuation in its plasma potential (Vp,u).

In alternate embodiments, a different plasma generation system (not shown) can be coupled to the plasma generation chamber416and configured to generate the upper plasma443in the upper plasma region442. The different plasma generation system may include 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. In addition, any ICP source can be used that produces a reduced or a minimum (Vp,u) fluctuation.

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).

Still referring toFIG. 4, the plasma generation subsystem415can include a plasma generation chamber416that can include a direct current (DC) conductive electrode417having a conductive surface that acts as a boundary in contact with the upper plasma443. The DC conductive ground electrode417is coupled to DC ground. For example, the DC conductive ground electrode417may comprise a doped silicon electrode. The DC conductive ground electrode417acts as an ion sink that is driven by the upper plasma443at an upper plasma potential (Vp,u). Although a single DC conductive ground electrode417is shown inFIG. 4, the Q-NB curing (hardening) system400may comprise one or more DC conductive ground electrodes.

Although not necessary, it is desirable that the DC conductive ground electrode417comprises a relatively large area in contact with the upper plasma443. The larger the area at DC ground, the lower the upper plasma potential. For example, the surface area of the conductive surface for the DC conductive ground electrode417in contact with the upper plasma443may be greater than any other surface area in contact with the upper plasma443. Additionally, for example, the surface area of the conductive surface for the DC conductive ground electrode417in contact with the upper plasma443may be greater than the total sum of all other conductive surfaces that are in contact with the upper plasma443. Alternatively, as an example, the conductive surface for the DC conductive ground electrode417in contact with the upper plasma443may be the only conductive surface that is in contact with the upper plasma443. The DC conductive ground electrode417may offer the lowest impedance path to ground.

In addition, the Q-NB curing (hardening) subsystem410can comprise a bias electrode system480coupled to the curing (hardening) chamber411. The bias electrode system480can be configured to elevate the curing (hardening) plasma potential to a value above the upper plasma potential in order to drive the electron flux in the correct direction. The bias electrode system480can include one or more first DC conductive bias electrodes482that have at least one first conductive surface in contact with the curing (hardening) plasma453, and one or more second DC conductive bias electrodes487that have at least one second conductive surface in contact with the curing (hardening) plasma453. The DC conductive bias electrodes (482and487) can be electrically insulated from the curing (hardening) chamber411using at least one insulator484and the DC conductive bias electrodes (482and487) can be coupled to a DC power source485. The conductive bias electrodes (482and487) can be composed of a conductive material, such as metal or doped silicon.

Although not necessary, it is desirable that the DC conductive bias electrodes (482and487) comprise a relatively large area in contact with the curing (hardening) plasma453. The larger the area at the +VDC potential, the closer the curing (hardening) plasma potential will be to +VDC. As an example, the total area of the DC conductive bias electrodes (482and487) can be greater than the total sum of all other conductive surfaces that are in contact with the curing (hardening) plasma453. Alternatively, as an example, the total area of the DC conductive bias electrodes (482and487) may be the only conductive surface that is in contact with the curing (hardening) plasma453.

The DC power source485can include a variable DC power supply. Additionally, the DC power source485can include a bipolar DC power supply. The DC power source485can further include a system configured to perform at least one of monitoring adjusting, or controlling the polarity, current, voltage, or on/off state of the DC power source485. An electrical filter may be utilized to de-couple RF power from the DC power source485.

For example, the DC voltage applied to the DC conductive bias electrodes (482and487) by DC power source485may range from approximately 0 volts (V) to approximately 10000 V. Desirably, the DC voltage applied to the DC conductive bias electrodes (482and487) by DC power source485may range from approximately 50 volts (V) to approximately 5000 V. Additionally, it is desirable that the DC voltage has a positive polarity. Furthermore, it is desirable that the DC voltage is a positive voltage having an absolute value greater than approximately 50 V.

As shown inFIG. 4, the curing (hardening) chamber411can include one or more chamber housing members that may be coupled to ground. Additionally, a liner member481can be disposed between one or more of the walls of the curing (hardening) chamber411and the curing (hardening) plasma453. For example, each liner member481can be fabricated from a dielectric material, such as quartz or alumina, and the liner member481can provide a high RF impedance to ground for the curing (hardening) plasma453.

In addition, the Q-NB curing (hardening) system400can include at least one separation member470that can be configured between the upper plasma region442and the curing (hardening) plasma region452. The separation member470can include one or more openings472that can be configured to create a plurality of beams350that can include at least one plasma species as well as an electron flux from the upper plasma443in the upper plasma region442to the curing (hardening) plasma region452. For example, the electrons and/or ions in the plurality of beams450can be used to form the curing (hardening) plasma453in the curing (hardening) plasma region452.

One or more of the openings472in the separation member470can comprise a super-Debye length apertures, i.e., the transverse dimension or diameter is larger than the Debye length. The openings472can be sufficiently large to permit adequate electron transport, and the openings472may be sufficiently small to allow a sufficiently high potential difference between the upper plasma potential and the curing (hardening) plasma potential and to reduce any reverse ion current between the curing (hardening) plasma453and the upper plasma443. Further, the one or more openings472may be sufficiently small to sustain a pressure difference between the first pressure in the upper plasma region442and the second pressure in the curing (hardening) plasma region452.

Although the DC conductive ground electrode417is coupled to DC ground, it may be coupled to a DC voltage less than the bias DC voltage coupled to the DC conductive bias electrodes (482and487).

As illustrated inFIG. 4, the plurality of beams450can include an electron flux that occurs between the upper plasma region442and the curing (hardening) plasma region452through separation member370. The electron transport is driven by electric field-enhanced diffusion, wherein the electric field is established by the potential difference between the first plasma potential and the curing (hardening) plasma potential. The plurality of beams450can include an electron flux that can be sufficiently energetic to sustain ionization in the curing (hardening) plasma453.

Pressure control system435can include a pump436that can be a turbo-molecular vacuum pump (TMP) capable of a pumping speed up to 5000 liters per second (and greater) and a vacuum valve437(or second vacuum valve), such as a gate valve, for controlling the pressure in the curing (hardening) plasma region452. Furthermore, one or more sensors439for monitoring chamber conditions can be coupled to the curing (hardening) chamber411, and one or more of the sensors439can be used to measure pressure in the curing (hardening) chamber411.

In some embodiments, the Q-NB curing (hardening) subsystem410can include a substrate holder420that can be coupled to ground. If the substrate holder420is coupled to ground, the patterned substrate425can be at floating ground, and therefore, the only ground the curing (hardening) plasma453contacts is the floating ground provided by patterned substrate425. For example, when the patterned substrate425is clamped to substrate holder420, a ceramic electrostatic clamp (ESC) layer may insulate the patterned substrate425from the grounded substrate holder420.

Referring still toFIG. 4, the Q-NB curing (hardening) subsystem410can include a substrate temperature control system428coupled to the substrate holder420and configured to adjust and control the temperature of patterned substrate425. The substrate temperature control system428can include temperature control elements429configured to control the temperature of the patterned substrate. Alternatively, temperature control elements (not shown) can be configured in a chamber wall of the curing (hardening) chamber411and/or any other component within the Q-NB curing (hardening) subsystem410.

In order to improve the thermal transfer between the patterned substrate425and substrate holder420, the substrate holder420can include electrostatic clamping (ESC) electrode423that can be coupled to a clamping supply422to affix the patterned substrate425to an upper surface of substrate holder420. In some embodiments, the electrostatic clamping (ESC) electrode423can be used to isolate the patterned substrate425from the grounded substrate holder420.

Furthermore, substrate holder420can further include backside gas elements427that can be coupled to a backside gas delivery system426that can be configured to introduce gas to the backside of the patterned substrate425in order to improve the gas-gap thermal conductance between the patterned substrate425and substrate holder420. Such a system can be utilized when temperature control of the patterned substrate425is required at elevated or reduced temperatures. For example, the substrate backside gas delivery system426can be coupled to a two-zone (center/edge) backside gas elements427, wherein the helium gas gap pressure can be independently varied between the center and the edge of the patterned substrate425. In other embodiments, the backside gas elements427can be used to isolate the patterned substrate425from the grounded substrate holder420.

In addition, the substrate holder420may be surrounded by a baffle member421that extends beyond a peripheral edge of the substrate holder420. The baffle member421may serve to homogeneously distribute the pumping speed delivered by the pressure control system435to the curing (hardening) plasma region452. The baffle member421may be fabricated from a dielectric material, such as quartz, or alumina. The baffle member421may provide a high impedance to ground for the curing (hardening) plasma453.

A transfer port401for a semiconductor substrate is formed in the sidewall of the curing (hardening) chamber411, and can be opened/closed by a gate valve402attached thereon. One or more of the controllers495can be coupled to gate valve402and can be configured to control gate valve402. The patterned substrate425can be, for example, transferred into and out of curing (hardening) chamber411through transfer port401and gate valve402from a transfer subsystem (170,FIG. 1), and it can be received by substrate lift pins (not shown) housed within substrate holder420and mechanically translated by devices (not show) housed therein. After the patterned substrate425is received from transfer system, it can be lowered to an upper surface of substrate holder420. The design and implementation of substrate lift pins is well known to those skilled in the art. Alternatively, an un-patterned substrate may be used.

In some embodiments, a conductive focus ring406can be used, and the conductive focus ring406can include a silicon-containing material and can be disposed on the top of the substrate holder420. In some examples, conductive focus ring406can be configured to surround the electrostatic electrode423, the backside gas elements427, and the patterned substrate425to improve uniformity at the edge of the substrate. In other examples, the conductive focus ring406can include a correction ring portion (not shown) that can be used to modify the edge temperature of the patterned substrates425. Alternatively, a non-conductive focus ring may be used.

In other embodiments, an inner deposition shield408can be detachably coupled to the substrate holder420to prevent by-products created during curing and/or hardening procedures from being deposited on the substrate holder420. In addition, an outer deposition shield (not shown) can be detachably coupled along one or more of the inner walls of the curing (hardening) chamber411to prevent by-products created during curing and/or hardening procedures from being deposited on the wall. For example, the outer deposition shield can be configured as a part of a chamber wall. The baffle member421and the deposition shield408can include an aluminum body covered with a ceramic, such as Y2O3. The gate valve437can be coupled to an exhaust space formed at the bottom of the curing (hardening) chamber411.

As depicted inFIG. 4, the Q-NB curing (hardening) subsystem410can include one or more first process sensors438coupled to the upper plasma region442and one or more second process sensors439coupled to the curing (hardening) plasma region452. Alternatively, the number and position of the process sensors (438,439) may be different. In various embodiments, the first process sensors438can include one or more optical devices for monitoring the light emitted from the upper plasma443in the upper plasma region442, and the second process sensors439can include one or more optical devices for monitoring the light emitted from the curing (hardening) plasma453in the curing (hardening) plasma region452. For example, one or more Optical Emission Spectroscopy (OES) sensors may be used, and the OES data can be used as ignition data, operational data, or endpoint data.

One or more of the process sensors (438,439) can include gas-sensing devices for monitoring and/or controlling input gasses, process gasses, and/or exhaust gasses. In addition, the one or more of the process sensors (438,439) can include pressure sensors, temperature sensors, current and/or voltage probes, power meters, spectrum analyzers, or an RF Impedance analyzer, or any combination thereof.

In addition, the Q-NB curing (hardening) subsystem410can include one or more internal sensors (not shown), and the internal sensors can include those sensors pertaining to the functionality of curing (hardening) chamber411, such as the measurement of the Helium backside gas pressure, Helium backside flow, electrostatic clamping (ESC) voltage, ESC current, substrate holder temperature (or lower electrode (LEL) temperature), coolant temperature, DC conductive bias electrode temperature, forward RF power, reflected RF power, electrode DC bias, RF peak-to-peak voltage, chamber wall temperature, process gas flow rates, process gas partial pressures, matching network settings, a focus ring thickness, RF hours, focus ring RF hours, and any statistic thereof.

Controller495can include one or more microprocessors, one or more memory elements, and one or more analog and/or digital I/O devices (potentially including D/A and/or ND converters) capable of generating control voltages sufficient to communicate and activate inputs to the Q-NB curing (hardening) system400as well as monitor outputs from Q-NB curing (hardening) system400. As shown inFIG. 4, controller495can be coupled to and exchange information with gate valve402, a clamping supply422, backside gas delivery system426, temperature control system428, sensors439, first gas supply system445, curing (hardening) gas supply system455, pressure control system435, power source460, and DC power source485. One or more programs stored in the memory can be utilized to interact with the aforementioned components of the Q-NB curing (hardening) system400according to stored process recipes. In addition, one or more first electrical supply elements483can be configured to allow electrical connection to the first DC conductive bias electrode482, and one or more second electrical supply elements488can be configured to allow electrical connection to the second DC conductive bias electrode487.

The plurality of controllers495may 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 controller/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 control 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.

When a curing and/or hardening process is performed by the Q-NB curing (hardening) system400, the gate valve402can be opened, and a patterned substrate425to be cured is transferred into the curing (hardening) chamber411and placed on the substrate holder420. The plasma generation subsystem415can provide a upper plasma species and the curing (hardening) chamber411can be configured to use a upper plasma species to facilitate the generation of curing (hardening) plasma453in curing (hardening) plasma region452adjacent a surface of the patterned substrate425. The curing (hardening) plasma species can include a fluorocarbon element (CxFy), such as C4F8, and may contain another component, such as Ar, or CO. The flow rate for the upper plasma species and/or the electrons can be established using the curing (hardening) recipe. In addition, an ionizable curing (hardening) gas or mixture of curing (hardening) gases can introduced from the curing (hardening) gas supply system455, and process pressure can be adjusted using pressure control system435. For example, the pressure inside plasma generation chamber416can range from about 1.0 mtorr (millitorr) to about 1200 mtorr, and the pressure inside the curing (hardening) chamber411can range between about 0.1 mtorr and about 150 mtorr. In other examples, the pressure inside plasma generation chamber416can range from about 10 mtorr to about 150 mtorr, and the pressure inside the curing (hardening) chamber411can range between about 1 mtorr and about 15 mtorr.

In some other embodiments, while the upper plasma species and the curing (hardening) gas is supplied into the curing (hardening) chamber411, independently controllable DC voltages can be applied from the DC power source485to the DC conductive bias electrodes (482and487). Furthermore, another DC voltage can be applied from the clamping supply422to the electrostatic electrode423to fix the semiconductor substrate on the substrate holder420. Radicals and ions generated in the curing (hardening) plasma453are used to cure the radiation-sensitive material (photoresist) layer on the patterned substrate425.

When the radiation-sensitive material (photoresist) film on the patterned substrate425is an ArF resist film, the ArF resist film changes its polymer structure when it is radiated with electrons. When the composition of the ArF resist film is reformed due to the resist cross-linkage reaction, the etching resistance property of the ArF resist film increases. In addition, the surface roughness of the ArF resist film is decreased. Therefore, the applied power from RF source460and DC power source485can be controlled by the controller495to enhance the etching resistance property of the radiation-sensitive material (photoresist) film (particularly, ArF resist film) by irradiation with electrons.

One or more of the process sensors439may be disposed to detect the plasma state, so that the controller495can control the flow rate for the first plasma species and the other radiation-sensitive material (photoresist) curing (hardening) recipe parameters using the detected plasma state. In addition, one or more sensors439may be used to measure the plasma sheath length or the electron density.

FIG. 5shows an exemplary flow diagram of a Q-NB curing and/or hardening procedure in accordance with embodiments of the invention. In the illustrated embodiment, a procedure500is provided of a method for curing and/or hardening an un-patterned and/or a patterned deposited layer on a substrate using a Q-NB curing (hardening) system such as shown inFIGS. 2A,2B,3, and4.

In510, a substrate can be position on a substrate holder in a curing (hardening) chamber in a Q-NB curing (hardening) system that can be configured to cure and/or harden an un-patterned and/or a patterned layer on a substrate using curing (hardening) plasma. The curing (hardening) chamber may include components of any one of the Q-NB curing (hardening) systems described herein. The substrate can have one or more deposited layers thereon, and the deposited layers can include Anti-Reflective Coating (ARC) material, Bottom Anti-Reflective Coating (BARC) material, Top Anti-Reflective Coating (TARC) material, single-frequency resist material, dual-tone resist material, freezable or frozen resist material, Ultra-Violet (UV) resist material, or Extreme Ultra-Violet (EUV) resist material, or any combination thereof. For example, during some Q-NB curing and/or hardening procedures, the substrate can have at least one un-exposed layer thereon, and during other Q-NB curing and/or hardening procedures, the substrate can have at least one exposed layer thereon. When the Q-NB curing and/or hardening procedures are performed during double-exposure sequences, different Q-NB curing and/or hardening recipes can be used during the different exposure procedures.

In520, first (upper) plasma can be created using a first process gas in a first (upper) plasma region at a first plasma potential. As illustrated inFIGS. 2A,2B,3, and4, the first (upper) 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 (upper) plasma. A first process gas can be provided to the plasma generation chamber, and the flow rate for the first process gas can be monitored and controlled to optimize the first (upper) plasma. In some alternate embodiments, the first (upper) plasma can be created before and/or while the substrate is being positioned on the substrate holder. For example, the first (upper) plasma may be in a lower power mode during substrate transfers.

In530, curing (hardening) plasma is formed in a curing (hardening) plasma region at a second curing (hardening) plasma potential using electron flux from the first plasma. Electron flux from the first plasma in the first plasma region passes from the plasma generation chamber through a separation member to a curing (hardening) chamber where the curing (hardening) plasma is created. A second process gas can be provided to the curing (hardening) plasma chamber, and the flow rate for the second process gas can be monitored and controlled to optimize the second curing (hardening) plasma. As illustrated inFIGS. 2A,2B,3, and4, the curing (hardening) plasma region can be located in the curing (hardening) chamber, wherein one or more openings or passages in the separation member disposed between the plasma generation chamber and the curing (hardening) chamber facilitate the transport or supply of electrons from the first plasma region to the curing (hardening) plasma region.

In540, the second curing (hardening) plasma potential can be elevated above the first plasma potential to control the electron flux. The first plasma in the first plasma region may be a boundary-driven plasma (i.e., the plasma boundary has a substantive influence on the respective plasma potential), wherein part or the entire boundary in contact with the first plasma is coupled to DC ground. Additionally, the curing (hardening) plasma in the curing (hardening) plasma region may be a boundary-driven plasma, wherein part or the entire boundary in contact with the curing (hardening) plasma is coupled to a DC power source at +VDC. The elevation of the second curing (hardening) plasma potential above the first (upper) plasma potential may be performed using any one or combination of the embodiments provided inFIGS. 2A,2B,3, and4.

In550, the curing (hardening) plasma can be maintained during a first Q-NB curing and/or hardening procedure. For example, the pressure in the curing (hardening) chamber can be controlled by pumping the curing (hardening) chamber and controlling the flow rate for the second process gas entering the curing (hardening) chamber.

In560, the substrate can be exposed to the curing (hardening) plasma in the curing (hardening) plasma region during the first Q-NB curing (hardening) procedure. The exposure of the substrate to the curing (hardening) plasma may comprise exposing the substrate to a mono-energetic space-charge neutralized Q-NB activated chemical process.

FIG. 6shows an exemplary flow diagram of another method for operating a Q-NB curing (hardening) subsystem in accordance with embodiments of the invention. In the illustrated embodiment, a procedure600is provided for a method of curing and/or hardening an un-patterned and/or a patterned layer on a substrate using a Q-NB curing (hardening) system such as shown inFIGS. 2A,2B,3, and4.

In610, a substrate can be position on a substrate holder in a curing (hardening) chamber in a Q-NB curing (hardening) system that can be configured to cure, freeze, and/or harden an un-patterned and/or a patterned layer on a substrate using curing (hardening) plasma. The curing (hardening) chamber may include components of any one of the Q-NB curing (hardening) systems described herein. The substrate can have one or more deposited layers thereon, and the deposited layers can include Anti-Reflective Coating (ARC) material, Bottom Anti-Reflective Coating (BARC) material, Top Anti-Reflective Coating (TARC) material, single-frequency resist material, dual-tone resist material, freezable or frozen resist material, Ultra-Violet (UV) resist material, or Extreme Ultra-Violet (EUV) resist material, or any combination thereof.

In some embodiments, a first set of un-patterned substrates can be received by a transfer subsystem (170,FIG. 1) that can be coupled to a Q-NB curing (hardening) subsystem (150,FIG. 1). Each un-patterned substrate can have at least one un-patterned masking layer that can be cured, frozen, and/or hardened by the Q-NB curing (hardening) subsystem (150,FIG. 1) before the un-patterned substrate is further processed by one or more of the subsystems (110,120,130,140,150,160, and170) in the processing system100.

In other embodiments, a first set of patterned substrates can be received by a transfer subsystem (170,FIG. 1) that can be coupled to a Q-NB curing (hardening) subsystem (150,FIG. 1). Each patterned substrate can have at least one patterned masking layer thereon that can be cured, frozen, and/or hardened by the Q-NB curing (hardening) subsystem (150,FIG. 1) before the patterned substrate is further processed by one or more of the subsystems (110,120,130,140,150,160, and170) in the processing system100. For example, during some Q-NB curing and/or hardening procedures, the patterned substrate can have at least one exposed masking layer thereon, and during other Q-NB curing and/or hardening procedures, the substrate can have at least one developed masking layer thereon. When some Q-NB curing and/or hardening procedures are performed, a plurality of cured, frozen, and/or hardened masking structures and/or periodic structures can be created.

When measurement data is required, one or more of the processed substrates can be transferred to the evaluation subsystem (160,FIG. 1), and measurement data can be obtained for the processed substrate using diffraction signal data from at least one of the plurality of cured, frozen, and/or hardened masking structures and/or periodic structures. In addition, risk data and/or confidence data for the processed substrates can be determined by comparing the measurement data to one or more Q-NB curing (hardening) limits and/or thresholds. For example, when the risk data is not less than a first risk limit for a Q-NB curing and/or hardening procedure, one or more corrective actions can be performed.

One or more of the controllers (114,124,134,144,154,164, and190) can be used to receive, determine, and/or send real-time and/or historical data associated with one or more of the first set of un-patterned and/or patterned substrates. For example, the real-time and/or historical data can include material data for patterned and/or un-patterned masking layers, metrology data for the gate-related masking features, and metrology data for the at least one periodic evaluation structure. In addition, the metrology data can include profile data, diffraction signal data, CD data, and SWA data that can be used to establish limits for the Q-NB curing and/or hardening procedure.

In620, a Q-NB can be created in the curing (hardening) chamber of a Q-NB curing (hardening) system that can be configured to cure and/or harden an un-patterned and/or a patterned layer on a substrate using curing (hardening) plasma. In some embodiments, first (upper) plasma can be created at a first plasma potential in a plasma generation chamber using a first process gas and a plasma generation system that can provide RF power when the first (upper) plasma is formed. The RF power and the flow rate for the first process gas can be monitored and controlled to optimize the first (upper) plasma.

In addition, curing (hardening) plasma can be formed in a curing (hardening) plasma region at a second curing (hardening) plasma potential using electron flux from the first plasma. Electron flux from the first plasma in the first plasma region passes from the plasma generation chamber through a separation member to a curing (hardening) chamber where the curing (hardening) plasma is created. A second process gas can be provided to the curing (hardening) plasma chamber, and the flow rate for the second process gas can be monitored and controlled to optimize the second curing (hardening) plasma. The second curing (hardening) plasma potential can be elevated above the first plasma potential to control the electron flux. The first plasma in the first plasma region may be a boundary-driven plasma (i.e., the plasma boundary has a substantive influence on the respective plasma potential), wherein part or the entire boundary in contact with the first plasma is coupled to DC ground. Additionally, the curing (hardening) plasma in the curing (hardening) plasma region may be a boundary-driven plasma, wherein part or the entire boundary in contact with the curing (hardening) plasma is coupled to a DC power source at +VDC. The elevation of the second curing (hardening) plasma potential above the first (upper) plasma potential may be performed using any one or combination of the embodiments provided inFIGS. 2A,2B,3, and4.

In630, a first Q-NB curing and/or hardening procedure can be performed during which at least one layer on a substrate can be exposed to the previously created Q-NB. In some embodiments, one or more polymer components in the masking material in the at least one layer can be de-coupled and removed during the first Q-NB curing and/or hardening procedure thereby creating a plurality of cured, frozen, and/or hardened structures. A protecting group or a blocking group can be a polymer group that can be used to protect a functional group from unwanted reactions, and first Q-NB curing and/or hardening procedure can be used to remove the protecting group or the blocking group thereby revealing the original functional group. In other examples, one or more leaving groups can be removed from one or more polymer chains during the first Q-NB curing and/or hardening procedure and reflectivity data for the at least one layer can be changed. In still other examples, a blocking group and/or protecting group can be de-blocked and/or de-protected during the first Q-NB curing and/or hardening procedure.

In640, a curing and/or hardening state can be determined and/or updated for the substrate while the first Q-NB curing and/or hardening procedure is being performed or after the first Q-NB curing and/or hardening procedure has been performed. For example, optical data can be used to determine the curing and/or hardening state. In other cases, endpoint data can be used to determine the curing and/or hardening state.

In650, at least one etching procedure can be performed when the curing and/or hardening state is equal to a first value. For example, when the curing and/or hardening state and the first value can be expressed as percentages, the first value can be established at approximately ninety percent. In some examples, a Q-NB etching procedure can be performed using the Q-NB curing (hardening) system. In other examples, the substrate can be transferred to an etching subsystem where one or more etching procedures can be performed.

In660, at least one corrective action can be performed when the curing and/or hardening state is not equal to a first value.

In some examples, corrective actions can include stopping the processing, pausing the processing, re-evaluating one or more of the substrates, re-measuring one or more of the substrates, re-inspecting one or more of the substrates, re-working one or more of the substrates, storing one or more of the substrates, cleaning one or more of the substrates, delaying one or more of the substrates, or stripping one or more of the substrates, or any combination thereof.

Corrective actions can include calculating new and/or updated Q-NB curing and/or hardening maps for the substrates. In addition, corrective actions can include increasing the number of required evaluation sites by one or more when one or more values in the Q-NB curing and/or hardening map are not within a limit; and decreasing the number of required evaluation sites by one or more when one or more values in the Q-NB curing and/or hardening map are within the limit.

In some examples, individual and/or total confidence values for the Q-NB curing and/or hardening procedure can be compared to individual and/or total confidence limits. The processing of a set of substrates can continue, if one or more of the confidence limits are met, or corrective actions can be applied if one or more of the confidence limits are not met. Corrective actions can include establishing confidence values for one or more additional substrates in the set of substrates, comparing the confidence values for one or more of the additional substrates to additional confidence limits; and either continuing the Q-NB curing and/or hardening procedure, if one or more of the additional confidence limits are met, or stopping the Q-NB curing and/or hardening procedure, if one or more of the additional confidence limits are not met.

In other examples, individual and/or total risk values for the substrate can be compared to individual and/or total risk limits. The processing of a set of substrates can continue, if one or more of the risk limits are met, or corrective actions can be applied if one or more of the risk limits are not met. Corrective actions can include establishing risk values for one or more additional substrates in the set of substrates, comparing the risk values for one or more of the additional substrates to additional risk limits; and either continuing the Q-NB curing and/or hardening procedure, if one or more of the additional risk limits are met, or stopping the Q-NB curing and/or hardening procedure, if one or more of the additional risk limits are not met.

FIG. 7illustrates an exemplary view of a Quasi-Neutral Beam (Q-NB) curing and/or hardening procedure using a metal gate structure in accordance with embodiments of the invention. In the illustrated embodiment, two exemplary gate stacks (701and702) are shown, but this is not required for the invention. Alternatively, a different number of gates stacks, a different number of models, and different configurations may be used.

First gate stack701is shown that includes a substrate layer710, a metal gate layer715, a first hard mask layer720, a first silicon-containing layer725, a second silicon-containing layer730, a second hard mask layer735, a gate-width control layer740, a third hard mask layer745, and a pattern of soft mask features750. For example, the substrate layer710can include a semiconductor material; the metal gate layer715can include HfO2; the first hard mask layer720can include TiN; the first silicon-containing layer725can include amorphous silicon (a-Si); the second silicon-containing layer730can include SiN; the second hard mask layer735can include TEOS; the gate-width control layer740can include an etch control material; the third hard mask layer745can include silicon-containing anti-reflective coating (SiARC) material; and the soft mask features750can include radiation-sensitive material (photoresist) material.

Second gate stack702is shown that includes a substrate layer710, a metal gate layer715, a first hard mask layer720, a first silicon-containing layer725, a second silicon-containing layer730, a second hard mask layer735, a gate-width control layer740, a third hard mask layer745, and a pattern of hardened soft mask features750a. For example, the substrate layer710can include a semiconductor material; the metal gate layer715can include HfO2; the first hard mask layer720can include TiN; the first silicon-containing layer725can include amorphous silicon (a-Si); the second silicon-containing layer730can include SiN; the second hard mask layer735can include TEOS; the gate-width control layer740can include an etch control material; the third hard mask layer745can include SiARC material; and the hardened soft mask features750acan include ArF photoresist material751and hardened ArF photoresist material752.

In additional examples, one or more Q-NB curing and/or hardening procedures can be performed when the third hard mask layer745is further processed, when the gate-width control layer740is further processed, when the second hard mask layer735is further processed, when the second silicon-containing layer730is further processed, when the first silicon-containing layer725is further processed, when the first hard mask layer720is further processed, when the metal gate layer715is further processed, and when the substrate layer710is further processed.

In still other embodiments, one or more substrates can be processed using a verified Q-NB curing and/or hardening procedure. When a verified Q-NB curing and/or hardening procedure is used, one or more verified structures can be created on a substrate (“golden wafer”). When the substrate is examined, a test reference structure can be selected from a number of verified structures on the substrate. During the examination, examination data can be obtained from the test reference structure. A best estimate structure and associated best estimate data can be selected from the library data that is associated with the Q-NB curing and/or hardening procedure and that includes verified structures and associated data. One or more differences can be calculated between the test reference structure and the best estimate structure from the library, the differences can be compared to matching criteria, creation criteria, or product requirements, or any combination thereof. When matching criteria are used, the test reference structure can be identified as an existing member of the Q-NB curing and/or hardening library, and the current substrate can be identified as a reference “golden” substrate if the matching criteria are met or exceeded. When creation criteria are used, the test reference structure can be identified as a new member of the Q-NB curing and/or hardening library, and the current substrate can be identified as a verified reference substrate if the creation criteria are met. When product requirement data is used, the test reference structure can be identified as a verified structure, and the substrate can be identified as verified production substrate if one or more product requirements are met. Corrective actions can be applied if one or more of the criteria or product requirements are not met. Confidence data and/or risk data can be established for the Q-NB curing and/or hardening procedure using the test reference structure data and the best estimate structure data.

When structures are produced and/or examined during a Q-NB curing and/or hardening procedure, accuracy and/or tolerance limits can be used. When these limits are not correct, refinement procedures can be performed. Alternatively, other procedures can be performed, other sites can be used, or other substrates can be used. When a refinement procedure is used, the refinement procedure can utilize bilinear refinement, Lagrange refinement, Cubic Spline refinement, Aitken refinement, weighted average refinement, multi-quadratic refinement, bi-cubic refinement, Turran refinement, wavelet refinement, Bessel's refinement, Everett refinement, finite-difference refinement, Gauss refinement, Hermite refinement, Newton's divided difference refinement, osculating refinement, or Thiele's refinement algorithm, or a combination thereof.

In some embodiments, the library data associated with a Q-NB curing and/or hardening procedure can include goodness of fit (GOF) data, creation rules data, measurement data, inspection data, verification data, map data, confidence data, accuracy data, process data, or uniformity data, or any combination thereof.

In some embodiments, the historical and/or real-time data can include hardness-related maps, substrate-related maps, process-related maps, damage-assessment maps, reference maps, measurement maps, prediction maps, risk maps, inspection maps, verification maps, evaluation maps, particle maps, and/or confidence map(s) for one or more substrates. In addition, some Q-NB curing and/or hardening procedures may use substrate maps that can include one or more Goodness Of Fit (GOF) maps, one or more thickness maps, one or more gate-related maps, one or more Critical Dimension (CD) maps, one or more CD profile maps, one or more material related maps, one or more structure-related maps, one or more sidewall angle maps, one or more differential width maps, or a combination thereof.

When substrate maps are created and/or modified, values may not be calculated and/or required for the entire substrate, and a substrate map may include data for one or more sites, one or more chip/dies, one or more different areas, and/or one or more differently shaped areas. For example, a curing and/or hardening chamber may have unique characteristics that may affect the quality of the processing results in certain areas of the substrate. In addition, a manufacturer may allow less accurate process and/or evaluation data for chips/dies in one or more regions of the substrate to maximize yield. When a value in a map is close to a limit, the confidence value may be lower than when the value in a map is not close to a limit. In addition, the accuracy values can be weighted for different chips/dies and/or different areas of the substrate. For example, a higher confidence weight can be assigned to the accuracy calculations and/or accuracy data associated with one or more of the previously used evaluation sites.

In addition, process result, measurement, inspection, verification, evaluation, and/or prediction maps associated with one or more processes may be used to calculate a confidence map for a substrate. For example, values from another map may be used as weighting factors.

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.

Thus, the description is not intended to limit the invention and the configuration, operation, and behavior of the present invention has been described with the understanding that modifications and variations of the embodiments are possible, given the level of detail present herein. Accordingly, the preceding detailed description is not mean or intended to, in any way, limit the invention—rather the scope of the invention is defined by the appended claims.