GCIB process for reducing interfacial roughness following pre-amorphization

A method for amorphizing a layer on a substrate is described. In one embodiment, the method includes treating the substrate with a first gas cluster ion beam (GCIB) using a first beam energy selected to yield an amorphous sub-layer within the substrate of a desired thickness, which produces a first interfacial roughness of an amorphous-crystal interface between the amorphous sub-layer and a crystalline sub-layer of the substrate. The method further includes treating the substrate with a second GCIB using a second beam energy, less than the first beam energy, to reduce the first interfacial roughness of the amorphous-crystal interface to a second interfacial roughness.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to forming an amorphous layer in a substrate.

2. Description of Related Art

The useful characteristics of semiconductor materials, such as silicon, germanium and gallium arsenide as well as other semiconductors, are contingent upon the purity and crystal structure of the semiconductor material. Dopant atoms incorporated into semiconductor materials for the purpose of altering electrical properties, forming electronic junctions, etc., are often introduced into a semiconductor surface by conventional ion implantation.

During the conventional process of ion implantation, ionized dopant atoms are physically deposited into a crystalline semiconductor material, but it is well known that, in doing so, the crystal lattice of the semiconductor becomes damaged by the implantation process. In order for the implanted dopant atoms to become electrically active within the semiconductor and to restore the desirable crystallinity of the semiconductor, the semiconductor crystal lattice structure must be restored and the implanted dopant atoms must occupy lattice sites within the restored crystal lattice by substitution. Processes typically employed to produce crystal lattice restoration and electrical activation of implanted dopant atoms include elevated temperature thermal annealing, pulsed laser beam annealing and pulsed electron beam annealing.

For some semiconductor products, an important requirement for the introduction of dopants into the semiconductor surface is that the maximum depth to which the dopant has penetrated after completion of the lattice re-crystallization and dopant activation processes must be kept very shallow, often only a few hundred Angstroms or less. By using very low energy conventional ion implantation, such shallow introduction of dopant is feasible by using very low implantation energies on the order of less than 1000 eV or in some cases even less than 200 eV. However, at such low energy, conventional ion implant often suffers from an energy contamination problem. When implanting some dopants, such as boron (B), a channeling effect is unavoidable unless the silicon (Si) lattice is pre-amorphized before the dopant implant. In conventional ion implant, this technique is known as pre-amorphization implant (PAI). High energy germanium (Ge) is often used for such purpose. The Ge PAI not only helps to prevent channeling but also helps to reduce B diffusion during anneal. But Ge PAI causes implant damage, often referred to as end-of-range damage that cannot be corrected by annealing. Such end-of-range damage results in high leakage current and other negative effect to devices.

Gas cluster ion beams (GCIBs) are used for etching, cleaning, smoothing, and forming thin films. For purposes of this discussion, gas clusters are nano-sized aggregates of materials that are gaseous under low-pressure, ultra-high vacuum (UHV) conditions used in typical ion implantation processes. Such gas clusters may consist of aggregates including a few to several thousand molecules, or more, that are loosely bound together through Van der Waals interaction. The gas clusters can be ionized by electron bombardment, which permits the gas clusters to be formed into directed beams of controllable energy. Such cluster ions each typically carry positive charges given by the product of the magnitude of the electronic charge and an integer greater than or equal to one that represents the charge state of the cluster ion.

The larger sized cluster ions are often the most useful because of their ability to carry substantial energy per cluster ion, while yet having only modest energy per individual molecule. The ion clusters disintegrate on impact with the substrate. Each individual molecule in a particular disintegrated ion cluster carries only a small fraction of the total cluster energy. Consequently, the impact effects of large ion clusters are substantial, but are limited to a very shallow surface region. This makes gas cluster ions effective for a variety of surface modification processes, but without the tendency to produce deeper sub-surface damage that is characteristic of conventional ion beam processing.

However, conventional GCIB processes still suffer from various deficiencies. Even with the aforementioned advantageous outcomes, GCIB processes can produce an uneven, pitted interface between the GCIB treated surface layer and the underlying untreated layer. There is thus a need to improve upon the use of GCIB processing for pre-amorphizing semiconductor materials to reduce interfacial deficiencies.

SUMMARY OF THE INVENTION

The invention relates to forming an amorphous sub-layer within a portion of a substrate. In particular, methods for amorphizing layers, including silicon-containing films, on a substrate using gas cluster ion beam (GCIB) processing are described in various embodiments. More specifically, the invention relates to forming an amorphous sub-layer using a first GCIB. According to one embodiment, the method further includes using a second GCIB to reduce an interfacial roughness between the amorphous sub-layer formed using the first GCIB and a crystalline sub-layer underlying the amorphous sub-layer.

According to another embodiment, a method for amorphizing a portion of a substrate is described. In one embodiment, the method may include treating at least a first portion of the substrate with a first GCIB using a first beam energy selected to yield an amorphous sub-layer from the first portion within the substrate of a desired thickness, wherein a second portion of the substrate is a crystalline sub-layer, and wherein the first GCIB treatment produces a first interfacial roughness of an amorphous-crystal interface between the amorphous sub-layer and the crystalline sub-layer of the substrate. The method further includes treating at least the first portion of the substrate with a second GCIB using a second beam energy, less than the first beam energy, to reduce the first interfacial roughness of the amorphous-crystal interface to a second interfacial roughness.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS

Methods for amorphizing layers, including silicon-containing films, on a substrate using gas cluster ion beam (GCIB) processing are described in various embodiments. One skilled in the relevant art will recognize that the various embodiments may be practiced without one or more of the specific details, or with other replacement and/or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention. Similarly, for purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the invention. Nevertheless, the invention may be practiced without specific details. Furthermore, it is understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

As described above, when treating a substrate or layer on or portion of a substrate, GCIB processes can produce an uneven, pitted interface between the GCIB treated surface layer or portion and the underlying untreated layer or portion. For example, when producing an amorphous sub-layer within a substrate using GCIB processing, the resultant interfacial roughness of an amorphous-crystal interface formed between the amorphous sub-layer, created using GCIB processing, and a crystalline sub-layer of the substrate that underlies the amorphous sub-layer can be unacceptable. In some cases, an uneven amorphous-crystalline interface with severe pitting can be observed.

Therefore, according to various embodiments, methods for amorphizing a layer on or portion of a substrate, while reducing interfacial roughness between an amorphous sub-layer and an underlying crystalline sub-layer, are disclosed. Referring now to the drawings wherein like reference numerals designate corresponding parts throughout the several views,FIG. 1provides a flow chart1illustrating a method for amorphizing a layer on a substrate according to an embodiment. Furthermore, a method for amorphizing a layer on a substrate is described inFIGS. 2A through 2D.

The method illustrated in flow chart1begins in10with disposing a substrate50in a GCIB processing system. At least a first portion50aof substrate50is arranged to be exposed to one or more GCIB treatments, while a second portion50bthat underlies the first portion50aremains untreated. The substrate50may include conductive materials, semi-conductive materials, or dielectric materials, or any combination of two or more thereof. For example, the substrate50may include a semiconductor material, such as silicon or germanium or a combination thereof. Additionally, for example, the substrate50may include crystalline silicon.

In11, as shown inFIGS. 2A and 2B, the first portion50aof substrate50is treated with a first GCIB70using a first beam energy selected to yield an amorphous sub-layer52from the first portion50awithin substrate50of a desired thickness62, while the second portion50bremains untreated as a crystalline sub-layer55. The treating of substrate50with the first GCIB70producing a first interfacial roughness64of an amorphous-crystal interface60between the amorphous sub-layer52and the crystalline sub-layer55of substrate50. The crystalline sub-layer55of substrate50may include crystalline silicon, and the amorphous sub-layer52may include amorphous silicon. In one embodiment, the first and second portions50a,50bof substrate50may comprise crystalline silicon, and the first portion50ais then amorphized by the GCIB treatment to yield amorphous silicon as amorphous sub-layer52, while leaving the second portion50bof crystalline silicon as crystalline sub-layer55.

In12, as shown inFIGS. 2C and 2D, the first portion50aof substrate50is treated with a second GCIB80using a second beam energy, less than the first beam energy, to reduce the first interfacial roughness64of the amorphous-crystal interface60to a second interfacial roughness64′, thus forming a modified amorphous-crystal interface60′. The GCIB treatment of substrate50with second GCIB80may produce a final thickness62′ that is substantially the same as the desired thickness62. The first GCIB70may be substantially the same beam as the second GCIB80, wherein the beam energy is adjusted from the first beam energy to the second beam energy in a continuous manner or a stepwise manner. Alternatively, the first GCIB70is different than the second GCIB80, wherein the beam energy is adjusted from the first beam energy to the second beam energy in a stepwise manner.

Additionally, the second GCIB80may be effective to reduce a first surface roughness66of an exposed surface65of the amorphous sub-layer52to a second surface roughness66′. Alternatively, or in addition, the first portion50aof substrate50may be treated with a third GCIB (not shown) using a third beam energy, less than the first beam energy to obtain the second surface roughness66′ or even a further reduced surface roughness. Furthermore, the third beam energy may be less than the second beam energy.

The degree of interfacial roughness and/or surface roughness may be a measure of the interfacial and/or surface unevenness. For example, the interfacial roughness and/or surface roughness may be characterized mathematically as a maximum roughness (Rmax), an average roughness (Ra), or a root-mean-square (rms) roughness (Rq).

The first GCIB70and/or second GCIB80can be formed in a GCIB processing system, such as any of the GCIB processing systems (100,100′ or100″) described below inFIG. 5,6or7, or any combination thereof. Therein, substrate50may be provided and maintained in a reduced-pressure environment. Substrate50may be positioned on a substrate holder and may be securely held by the substrate holder. The temperature of substrate50may or may not be controlled. For example, substrate50may be heated or cooled during a GCIB treatment process.

The first GCIB70and/or second GCIB80may be generated from a pressurized gas mixture that includes a noble gas (i.e., He, Ne, Ar, Kr, Xe). Additionally, the first GCIB70and/or second GCIB80may be generated from a pressurized gas mixture that includes at least one noble gas and molecules containing an element, or elements, selected from the group consisting of B, C, Se, Te, Si, Ge, N, P, As, O, S, F, Cl, and Br. Furthermore, the first GCIB70and/or second GCIB80may be generated from a pressurized gas mixture that includes at least one dopant, etchant, or film forming constituent for depositing or growing a thin film, or any combination of two or more thereof.

As described above, two or more GCIB treatments may be programmed to modify and/or enhance substrate50. For example, the first GCIB70and the second GCIB80may be programmed to produce an amorphous sub-layer having a desired thickness and an acceptable interfacial roughness at the amorphous-crystal interface between the amorphous sub-layer and the underlying crystalline sub-layer. In any one of these GCIB treatments, including the first GCIB70and/or the second GCIB80, a GCIB operation may comprise: establishing a GCIB; selecting at least one of a beam energy, a beam energy distribution, a beam focus, and a beam dose; accelerating the GCIB to achieve the beam energy; focusing the GCIB to achieve the beam focus; and exposing the portion of the substrate to the accelerated GCIB according to the beam dose.

Furthermore, in addition to beam energy, beam energy distribution, beam focus, and beam dose, a stagnation pressure, a stagnation temperature, a mass flow rate, a cluster size, a cluster size distribution, a beam size, a beam composition, a beam electrode potential, or a gas nozzle design (such as nozzle throat diameter, nozzle length, and/or nozzle divergent section half-angle) may be selected. Any one or more of the aforementioned GCIB properties can be selected to achieve pre-specified properties of the substrate50, including the amorphous sub-layer52. For example, any one of these GCIB properties may be adjusted to alter properties of the substrate50, i.e., alter a phase (amorphous or crystalline) of a sub-layer within the substrate, alter a thickness of a sub-layer within the substrate, alter an interfacial roughness of a sub-layer within the substrate, alter a surface roughness of a sub-layer within the substrate, alter a concentration of one or more species within the substrate, alter a concentration profile of one or more species within the substrate, or alter a depth of one or more species within the substrate, or any combination thereof.

For the first GCIB70and/or the second GCIB80, the beam acceleration potential may range up to 100 kV, the beam energy may range up to 100 keV, the cluster size may range up to several tens of thousands of atoms, and the beam dose may range up to about 1×1017clusters per cm2. For example, the beam acceleration potential of the first GCIB70and/or the second GCIB80may range from about 1 kV to about 70 kV (i.e., the beam energy may range from about 1 keV to about 70 keV, assuming an average cluster charge state of unity). Additionally, for example, the beam dose of the first GCIB70and/or the second GCIB80may range from about 1×1012clusters per cm2to about 1×1014clusters per cm2.

The first GCIB70and/or second GCIB80may be established having an energy per atom ratio ranging from about 0.25 eV per atom to about 100 eV per atom. Alternatively, the first GCIB70and/or second GCIB80may be established having an energy per atom ratio ranging from about 0.25 eV per atom to about 10 eV per atom. Alternatively, the first GCIB70and/or second GCIB80may be established having an energy per atom ratio ranging from about 1 eV per atom to about 10 eV per atom.

The establishment of the first GCIB70and/or the second GCIB80having a desired energy per atom ratio may include selection of a beam acceleration potential, a stagnation pressure for formation of the first GCIB70and/or the second GCIB80, or a gas flow rate, or any combination thereof. The beam acceleration potential may be used to increase or decrease the beam energy or energy per ion cluster. For example, an increase in the beam acceleration potential causes an increase in the maximum beam energy and, consequently, an increase in the energy per atom ratio for a given cluster size. Additionally, the stagnation pressure may be used to increase or decrease the cluster size for a given cluster. For example, an increase in the stagnation pressure during formation of the GCIB causes an increase in the cluster size (i.e., number of atoms per cluster) and, consequently, a decrease in the energy per atom ratio for a given beam acceleration potential.

As described above, the second beam energy is selected to be less than the first beam energy. The first beam energy may be greater than about 1 keV (kilo-electron volts). Alternatively, the first beam energy may be greater than about 5 keV. Alternatively, the first beam energy may be greater than about 10 keV. Alternatively, the first beam energy may be greater than about 20 keV. Alternatively yet, the first beam energy may be greater than about 30 keV. The second beam energy may be less than about 30 keV. Alternatively, the second beam energy may be less than about 20 keV. Alternatively, the second beam energy may be less than about 10 keV. Alternatively yet, the second beam energy may be less than about 5 keV. Alternately yet, the second beam energy may be less than about 1 keV.

Herein, beam dose is given the units of number of clusters per unit area. However, beam dose may also include beam current and/or time (e.g., GCIB dwell time). For example, the beam current may be measured and maintained constant, while time is varied to change the beam dose. Alternatively, for example, the rate at which clusters strike the surface of the substrate per unit area (i.e., number of clusters per unit area per unit time) may be held constant while the time is varied to change the beam dose.

According to one embodiment, the GCIB treatment may comprise selecting the first beam energy and a first beam dose to achieve desired thickness62of the amorphous sub-layer52formed during the irradiating of the portion of the substrate50with the first GCIB70. Additionally, the GCIB treatment may further comprise selecting the second beam energy and a second beam dose to achieve second interfacial roughness64′ of the amorphous sub-layer52formed during the irradiating the portion of the substrate50with the second GCIB80.

Referring now toFIG. 3, the thickness of the amorphous sub-layer52is plotted as a function of time (or beam dose), wherein the thickness increases with time until it eventually saturates. The maximum thickness and the elapsed time associated with substantially achieving the maximum thickness of the amorphous sub-layer52depend on the beam energy or beam acceleration potential, i.e., the first beam energy. For example, three exemplary data sets are illustrated for low beam energy (or low beam acceleration potential) (dotted line), moderate beam energy (or moderate beam acceleration potential) (solid line), and high beam energy (or high beam acceleration potential) (dashed line). In each data set, the beam energy (e.g., high, moderate, low) represents the peak beam energy for a relatively narrow beam energy distribution.

Additionally, the first interfacial roughness64(measured as average roughness, Ra) and the first surface roughness66(measured as average roughness, Ra) depends on the beam acceleration potential or beam energy, i.e., the first beam energy. As the beam acceleration or beam energy is increased to achieve the desired thickness62, the first interfacial roughness64and first surface roughness66are increased. Conversely, as the beam acceleration or beam energy is decreased to achieve the desired thickness62, the first interfacial roughness64and first surface roughness66are decreased, as shown by the arrows inFIG. 3.

Furthermore, while not shown inFIG. 3, the first interfacial roughness64and first surface roughness66may be decreased by decreasing the energy per atom ratio. Alternatively, the first interfacial roughness64and first surface roughness66may be increased by increasing the energy per atom ratio.

As will be discussed in greater detail below, GCIB treatment with the second GCIB80may be used to reduce the first interfacial roughness64to the second interfacial roughness64′ and to achieve the final thickness62′. GCIB treatment with the second GCIB80may, at least in part, reduce the first surface roughness66to the second surface roughness66′. Furthermore, additional GCIB treatment, for example with a third GCIB, may be used to reduce the first surface roughness66to the second surface roughness66′. The same parameters for the first GCIB70that can be selected and adjusted to achieve the first interfacial/surface roughness64,66and desired thickness62can likewise be selected and adjusted for the second GCIB80to achieve the second interfacial/surface roughness64′,66′ and final thickness62′.

Referring again toFIG. 3, for example, a fourth exemplary data set is illustrated for high beam energy (or high beam acceleration potential) and broad beam energy distribution (dashed-dot line). The thickness varies with time in a manner similar to the relatively low beam energy and narrow beam energy distribution data (dotted line), yet the first and second interfacial roughness64,64′ and first and second surface roughness66,66′ may be further reduced.

The beam energy distribution function for the first GCIB70and/or the second GCIB80may be modified by directing the respective GCIB along a GCIB path through an increased pressure region such that at least a portion of the GCIB traverses the increased pressure region. The extent of modification to the beam energy distribution may be characterized by a pressure-distance (d) integral along the at least a portion of the GCIB path. When the value of the pressure-distance integral is increased (either by increasing the pressure and/or the path length (d)), the beam energy distribution is broadened and the peak energy is decreased. When the value of the pressure-distance integral is decreased (either by decreasing the pressure and/or the path length (d)), the beam energy distribution is narrowed and the peak energy is increased. As an example, one may broaden the beam energy distribution to decrease the interfacial/surface roughness64,64′,66,66′, or one may narrow the beam energy distribution to increase the interfacial/surface roughness64,64′,66,66′, as described above.

The pressure-distance integral along the at least a portion of the GCIB path may be equal to or greater than about 0.0001 torr-cm. Alternatively, the pressure-distance integral along the at least a portion of the GCIB path may be equal to or greater than about 0.001 torr-cm. Alternatively yet, the pressure-distance integral along the at least a portion of the GCIB path may be equal to or greater than about 0.01 torr-cm.

Alternatively, the beam energy distribution function for the first GCIB70and/or the second GCIB80may be modified by modifying or altering a charge state of the respective GCIB. For example, the charge state may be modified by adjusting an electron flux, an electron energy, or an electron energy distribution for electrons utilized in electron collision-induced ionization of gas clusters.

As described above, when a desired thickness62is selected and achieved using the first GCIB70, the resultant amorphous sub-layer52exhibits interfacial roughness64at the amorphous-crystalline interface60representative of the exemplary data provided inFIG. 3. Thereafter, the amorphous sub-layer52is subjected to treatment by the second GCIB80, having second beam energy less than the first beam energy, and the interfacial roughness64is further reduced.

Referring now toFIGS. 4A and 4B, an amorphous silicon sub-layer is formed in a crystalline silicon substrate using GCIB treatment. InFIG. 4A, a 10 nm (nanometer) thick amorphous silicon sub-layer is formed using a first GCIB at a beam acceleration potential of 10 kV. A 5 nm iridium cap layer is formed above the amorphous sub-layer to provide greater contrast to the amorphous silicon sub-layer (lighter layer) sandwiched between the underlying crystalline silicon sub-layer (dark layer) and the iridium cap layer (darker layer). Inspection of the amorphous silicon sub-layer indicates that the amorphous-crystalline interface exhibits heavy pitting and may be characterized with a high degree of interfacial roughness.

InFIG. 4B, the amorphous silicon sub-layer is subjected to a second GCIB at a beam acceleration potential of 8 kV (a beam acceleration potential, and corresponding beam energy, less than the beam acceleration potential and beam energy of the first GCIB). Inspection of the amorphous silicon sub-layer indicates that the interfacial roughness of the amorphous-crystalline interface is substantially reduced.

According to another embodiment, the first GCIB70and/or second GCIB80may be used to form a mixed layer in substrate50, wherein the mixed layer is either graded or non-graded. Additionally, the mixed layer may include one or more elements, dopants, and/or impurities infused using the first GCIB70and/or second GCIB80. Furthermore, the mixed layer may include a concentration profile extending partly or fully through the mixed layer that is tailored via adjustment of one or more GCIB processing parameters of the first GCIB70and/or second GCIB80. The mixed layer may or may not coincide with the amorphous sub-layer52.

The beam acceleration potential (or beam energy, e.g., the first beam energy) may be used to modify the thickness62,62′, or depth of penetration of the one or more elements in the substrate50, i.e., increasing the beam acceleration potential increases the thickness or depth of penetration, and decreasing the beam acceleration potential decreases the thickness or depth of penetration. Additionally, the beam dose may be used to modify the concentration of the one or more elements in the substrate50, i.e., increasing the beam dose increases the amorphization or final concentration, and decreasing the beam dose decrease the amorphization or final concentration. The first GCIB70and/or the second GCIB80may be accelerated according to the beam acceleration potential, and the substrate50is exposed to the first GCIB70and/or the second GCIB80according to the beam dose.

Furthermore, the energy per atom ratio may be used to adjust the concentration of one or more elements present or not present in the substrate50, the thickness62,62′ or depth of penetration to which the one or more elements are present in the substrate50. For instance, while decreasing the energy per atom ratio, the depth of penetration may be decreased. Alternatively, while increasing the energy per atom ratio, the depth of penetration may be increased.

According to another embodiment, the first GCIB70and/or second GCIB80may be used to grow a sub-layer on substrate50, wherein the grown layer is either graded or non-graded. The growth process may, for example, include an oxidation or nitridation process. Additionally, the grown layer may include one or more elements, dopants, and/or impurities infused using the first GCIB70and/or second GCIB80. Furthermore, the grown layer may include a concentration profile extending partly or fully through the grown layer that is tailored via adjustment of one or more GCIB processing parameters of the first GCIB70and/or second GCIB80. The grown layer may or may not coincide with the amorphous sub-layer52. As described above, one or more GCIB parameters may be adjusted to achieve a desired thickness or depth of penetration of the grown layer.

According to another embodiment, in addition to irradiation of substrate50with the first GCIB70and second GCIB80, another GCIB may be used for additional control and/or function. Irradiation of the substrate50by another GCIB, such as the third GCIB, may proceed before, during, or after use of the first GCIB70and/or second GCIB80. For example, another GCIB may be used to dope a portion of the substrate50with an impurity. Additionally, for example, another GCIB may be used to modify a portion of the substrate50to alter properties of substrate50. Additionally, for example, another GCIB may be used to etch a portion of the substrate50to remove material from substrate50. Additionally yet, for example, another GCIB may be used to grow or deposit material on a portion of the substrate50. The doping, modifying, etching, growing, or depositing may comprise introducing one or more elements selected from the group consisting of He, Ne, Ar, Xe, Kr, B, C, Se, Te, Si, Ge, N, P, As, O, S, F, Cl, and Br.

According to another embodiment, the first portion50aof substrate50subjected to GCIB irradiation may be cleaned before or after the irradiating with the first GCIB70and/or the second GCIB80. For example, the cleaning process may include a dry cleaning process and/or a wet cleaning process. Additionally, the first portion50aof substrate50subjected to GCIB irradiation may be annealed after the irradiating with the first GCIB70and/or the second GCIB80.

According to another embodiment, one or more thermal anneals may be performed to program, modify, and/or enhance the amorphous sub-layer52and properties in substrate50. For any one of these thermal anneals, the substrate50may be subjected to a thermal treatment, wherein the temperature of the substrate50is elevated to a material-specific temperature for a period of time. The temperature and the time for the annealing process may be adjusted in order to vary the properties of the substrate50. For example, the temperature of the substrate50may be elevated to a value greater than about 800 degrees C. Additionally, for example, the temperature of the substrate may be elevated to a value greater than about 850 degrees C. Additionally yet, for example, the temperature of the substrate may be elevated to a value greater than about 900 degrees C. Furthermore, for example, the time for the annealing process may be greater than about 1 millisecond. The annealing process may be performed at atmospheric pressure or reduced pressure. Additionally, the annealing process may be performed with or without an inert gas atmosphere. Furthermore, the annealing process may be performed in a furnace, a rapid thermal annealing (RTP) system, a flash lamp annealing system, or a laser annealing system.

According to another embodiment, when preparing substrate50, any portion of substrate50or the amorphous-crystal interface60may be subjected to corrective processing. During corrective processing, metrology data may be acquired using a metrology system coupled to a GCIB processing system, either in-situ or ex-situ. The metrology system may comprise any variety of substrate diagnostic systems including, but not limited to, optical diagnostic systems, X-ray fluorescence spectroscopy systems, four-point probing systems, transmission-electron microscope (TEM), atomic force microscope (AFM), scanning-electron microscope (SEM), etc. Additionally, the metrology system may comprise an optical digital profilometer (ODP), a scatterometer, an ellipsometer, a reflectometer, an interferometer, or any combination of two or more thereof.

For example, the metrology system may constitute an optical scatterometry system. The scatterometry system may include a scatterometer, incorporating beam profile ellipsometry (ellipsometer) and beam profile reflectometry (reflectometer), commercially available from Therma-Wave, Inc. (1250 Reliance Way, Fremont, Calif. 94539) or Nanometrics, Inc. (1550 Buckeye Drive, Milpitas, Calif. 95035). Additionally, for example, the in-situ metrology system may include an integrated Optical Digital Profilometry (iODP) scatterometry module configured to measure metrology data on a substrate.

The metrology data may include parametric data, such as geometrical, mechanical, electrical and/or optical parameters associated with the substrate, any layer or sub-layer formed on the substrate, and/or any portion of a device on the substrate. For example, metrology data can include any parameter measurable by the metrology systems described above. Additionally, for example, metrology data can include a film thickness, a surface and/or interfacial roughness, a surface contamination, a feature depth, a trench depth, a via depth, a feature width, a trench width, a via width, a critical dimension (CD), an electrical resistance, or any combination of two or more thereof.

The metrology data may be measured at two or more locations on the substrate. Moreover, this data may be acquired and collected for one or more substrates. The one or more substrates may, for instance, include a cassette of substrates. The metrology data is measured at two or more locations on at least one of the one or more substrates and may, for example, be acquired at a plurality of locations on each of the one or more substrates. Thereafter, the plurality of locations on each of the plurality of substrates can be expanded from measured sites to unmeasured sites using a data fitting algorithm. For example, the data fitting algorithm can include interpolation (linear or nonlinear) or extrapolation (linear or nonlinear) or a combination thereof.

Once metrology data is collected for the one or more substrates using the metrology system, the metrology data is provided to a controller for computing correction data. Metrology data may be communicated between the metrology system and the controller via a physical connection (e.g., a cable), or a wireless connection, or a combination thereof. Additionally, the metrology data may be communicated via an intranet or Internet connection. Alternatively, metrology data may be communicated between the metrology system and the controller via a computer readable medium.

Correction data may be computed for location specific processing of the substrate. The correction data for a given substrate comprises a process condition for modulation of the GCIB dose as a function of position on the substrate in order to achieve a change between the parametric data associated with the incoming metrology data and the target parametric data for the given substrate. For example, the correction data for a given substrate can comprise determining a process condition for using the GCIB to correct a non-uniformity of the parametric data for the given substrate. Alternatively, for example, the correction data for a given substrate can comprise determining a process condition for using the GCIB to create a specifically intended non-uniformity of the parametric data for the given substrate.

Using an established relationship between the desired change in parametric data and the GCIB dose and an established relationship between the GCIB dose and a GCIB process condition having a set of GCIB processing parameters, the controller determines correction data for each substrate. For example, a mathematical algorithm can be employed to take the parametric data associated with the incoming metrology data, compute a difference between the incoming parametric data and the target parametric data, invert the GCIB processing pattern (i.e., etching pattern or deposition pattern or both) to fit this difference, and create a beam dose contour to achieve the GCIB processing pattern using the relationship between the change in parametric data and the GCIB dose. Thereafter, for example, GCIB processing parameters can be determined to affect the calculated beam dose contour using the relationship between the beam dose and the GCIB process condition. The GCIB processing parameters can include a beam dose, a beam area, a beam profile, a beam intensity, a beam scanning rate, or an exposure time (or beam dwell time), or any combination of two or more thereof.

Many different approaches to the selection of mathematical algorithm may be successfully employed in this embodiment. In another embodiment, the beam dose contour may selectively deposit additional material in order to achieve the desired change in parametric data.

The correction data may be applied to the substrate using a GCIB. During corrective processing, the GCIB may be configured to perform at least one of smoothing, amorphizing, modifying, doping, etching, growing, or depositing, or any combination of two or more thereof. The application of the corrective data to the substrate may facilitate correction of substrate defects, correction of substrate surface planarity, correction of layer thickness, or improvement of layer adhesion. Once processed to GCIB specifications, the uniformity of the substrate(s) or distribution of the parametric data for the substrate(s) may be examined either in-situ or ex-situ, and the process may be finished or refined as appropriate.

According to yet another embodiment, a method for patterning the GCIB treatment of substrate50, including GCIB treatment with the first GCIB70and the second GCIB80, is described. The method comprises forming a patterned mask layer on a surface of substrate50, treating a surface of substrate50exposed through the patterned mask layer using the first GCIB70, the second GCIB80, and/or another GCIB, and removing the patterned mask layer. The use of a patterned mask layer during the GCIB treatment with the first GCIB70, the second GCIB80, and/or another GCIB can facilitate patterning the distribution of GCIB treatment across substrate50.

The patterned mask layer may be formed by coating substrate50with a layer of radiation-sensitive material, such as photo-resist. For example, photo-resist may be applied to the substrate using a spin coating technique, such as those processes facilitated by a track system. Additionally, for example, the photo-resist layer is exposed to an image pattern using a photo-lithography system, and thereafter, the image pattern is developed in a developing solvent to form a pattern in the photo-resist layer.

The photo-resist layer may comprise 248 nm (nanometer) resists, 193 nm resists, 157 nm resists, or EUV (extreme ultraviolet) resists. The photo-resist layer can be formed using a track system. For example, the track system can comprise a Clean Track ACT 8, ACT 12, or Lithius resist coating and developing system commercially available from Tokyo Electron Limited (TEL). Other systems and methods for forming a photo-resist film on a substrate are well known to those skilled in the art of spin-on resist technology.

The exposure to electro-magnetic (EM) radiation through a reticle is performed in a dry or wet photo-lithography system. The image pattern can be formed using any suitable conventional stepping lithographic system, or scanning lithographic system. For example, the photo-lithographic system may be commercially available from ASML Netherlands B.V. (De Run 6501, 5504 DR Veldhoven, The Netherlands), or Canon USA, Inc., Semiconductor Equipment Division (3300 North First Street, San Jose, Calif. 95134).

The developing process can include exposing the substrate to a developing solvent in a developing system, such as a track system. For example, the track system can comprise a Clean Track ACT 8, ACT 12, or Lithius resist coating and developing system commercially available from Tokyo Electron Limited (TEL).

The photo-resist layer may be removed using a wet stripping process, a dry plasma ashing process, or a dry non-plasma ashing process.

The patterned mask layer may include multiple layers, wherein the pattern formed in the multi-layer mask layer may be created using wet processing techniques, dry processing techniques, or a combination of both techniques. The formation of a patterned mask layer having a single layer or multiple layers is understood to those skilled in the art of lithography and pattern etching technology.

Referring now toFIG. 5, a GCIB processing system100for treating a substrate as described above is depicted according to an embodiment. The GCIB processing system100comprises a vacuum vessel102, substrate holder150, upon which a substrate152to be processed is affixed, and vacuum pumping systems170A,170B, and170C. Substrate152can be a semiconductor substrate, a wafer, a flat panel display (FPD), a liquid crystal display (LCD), or any other workpiece. GCIB processing system100is configured to produce a GCIB for treating substrate152.

Referring still to GCIB processing system100inFIG. 5, the vacuum vessel102comprises three communicating chambers, namely, a source chamber104, an ionization/acceleration chamber106, and a processing chamber108to provide a reduced-pressure enclosure. The three chambers are evacuated to suitable operating pressures by vacuum pumping systems170A,170B, and170C, respectively. In the three communicating chambers104,106,108, a gas cluster beam can be formed in the first chamber (source chamber104), while a GCIB can be formed in the second chamber (ionization/acceleration chamber106) wherein the gas cluster beam is ionized and accelerated. Then, in the third chamber (processing chamber108), the accelerated GCIB may be utilized to treat substrate152.

Although specific examples are provided for transistor gate and trench capacitor applications, the methods of etching, as described above, may be utilized in any substrate processing wherein etching is necessitated.

As shown inFIG. 5, GCIB processing system100can comprise one or more gas sources configured to introduce one or more gases or mixture of gases to vacuum vessel102. For example, a first gas composition stored in a first gas source111is admitted under pressure through a first gas control valve113A to a gas metering valve or valves113. Additionally, for example, a second gas composition stored in a second gas source112is admitted under pressure through a second gas control valve113B to the gas metering valve or valves113. Further, for example, the first gas composition or second gas composition or both can include a condensable inert gas, carrier gas or dilution gas. For example, the inert gas, carrier gas or dilution gas can include a noble gas, i.e., He, Ne, Ar, Kr, Xe, or Rn.

Furthermore, the first gas source111and the second gas source112may be utilized either alone or in combination with one another to produce ionized clusters. The material composition can include the principal atomic or molecular species of the elements desired to be introduced to the material layer.

The high pressure, condensable gas comprising the first gas composition or the second gas composition or both is introduced through gas feed tube114into stagnation chamber116and is ejected into the substantially lower pressure vacuum through a properly shaped nozzle110. As a result of the expansion of the high pressure, condensable gas from the stagnation chamber116to the lower pressure region of the source chamber104, the gas velocity accelerates to supersonic speeds and gas cluster beam118emanates from nozzle110.

The inherent cooling of the jet as static enthalpy is exchanged for kinetic energy, which results from the expansion in the jet, causes a portion of the gas jet to condense and form a gas cluster beam118having clusters, each consisting of from several to several thousand weakly bound atoms or molecules. A gas skimmer120, positioned downstream from the exit of the nozzle110between the source chamber104and ionization/acceleration chamber106, partially separates the gas molecules on the peripheral edge of the gas cluster beam118, that may not have condensed into a cluster, from the gas molecules in the core of the gas cluster beam118, that may have formed clusters. Among other reasons, this selection of a portion of gas cluster beam118can lead to a reduction in the pressure in the downstream regions where higher pressures may be detrimental (e.g., ionizer122, and processing chamber108). Furthermore, gas skimmer120defines an initial dimension for the gas cluster beam entering the ionization/acceleration chamber106.

After the gas cluster beam118has been formed in the source chamber104, the constituent gas clusters in gas cluster beam118are ionized by ionizer122to form GCIB128. The ionizer122may include an electron impact ionizer that produces electrons from one or more filaments124, which are accelerated and directed to collide with the gas clusters in the gas cluster beam118inside the ionization/acceleration chamber106. Upon collisional impact with the gas cluster, electrons of sufficient energy eject electrons from molecules in the gas clusters to generate ionized molecules. The ionization of gas clusters can lead to a population of charged gas cluster ions, generally having a net positive charge.

As shown inFIG. 5, beam electronics130are utilized to ionize, extract, accelerate, and focus the GCIB128. The beam electronics130include a filament power supply136that provides voltage VFto heat the ionizer filament124.

Additionally, the beam electronics130include a set of suitably biased high voltage electrodes126in the ionization/acceleration chamber106that extracts the cluster ions from the ionizer122. The high voltage electrodes126then accelerate the extracted cluster ions to a desired energy and focus them to define GCIB128. The kinetic energy of the cluster ions in GCIB128typically ranges from about 1000 electron volts (1 keV) to several tens of keV. For example, GCIB128can be accelerated to 1 to 100 keV.

As illustrated inFIG. 4, the beam electronics130further include an anode power supply134that provides voltage VAto an anode of ionizer122for accelerating electrons emitted from filament124and causing the electrons to bombard the gas clusters in gas cluster beam118, which produces cluster ions.

Additionally, as illustrated inFIG. 4, the beam electronics130include an extraction power supply138that provides voltage VEEto bias at least one of the high voltage electrodes126to extract ions from the ionizing region of ionizer122and to form the GCIB128. For example, extraction power supply138provides a voltage to a first electrode of the high voltage electrodes126that is less than or equal to the anode voltage of ionizer122.

Furthermore, the beam electronics130can include an accelerator power supply140that provides voltage VACCto bias one of the high voltage electrodes126with respect to the ionizer122so as to result in a total GCIB acceleration energy equal to about VACCelectron volts (eV). For example, accelerator power supply140provides a voltage to a second electrode of the high voltage electrodes126that is less than or equal to the anode voltage of ionizer122and the extraction voltage of the first electrode.

Further yet, the beam electronics130can include lens power supplies142,144that may be provided to bias some of the high voltage electrodes126with potentials (e.g., VL1and VL2) to focus the GCIB128. For example, lens power supply142can provide a voltage to a third electrode of the high voltage electrodes126that is less than or equal to the anode voltage of ionizer122, the extraction voltage of the first electrode, and the accelerator voltage of the second electrode, and lens power supply144can provide a voltage to a fourth electrode of the high voltage electrodes126that is less than or equal to the anode voltage of ionizer122, the extraction voltage of the first electrode, the accelerator voltage of the second electrode, and the first lens voltage of the third electrode.

Note that many variants on both the ionization and extraction schemes may be used. While the scheme described here is useful for purposes of instruction, another extraction scheme involves placing the ionizer and the first element of the extraction electrode(s) (or extraction optics) at VACC. This typically requires fiber optic programming of control voltages for the ionizer power supply, but creates a simpler overall optics train. The invention described herein is useful regardless of the details of the ionizer and extraction lens biasing.

A beam filter146in the ionization/acceleration chamber106downstream of the high voltage electrodes126can be utilized to eliminate monomers, or monomers and light cluster ions from the GCIB128to define a filtered process GCIB128A that enters the processing chamber108. In one embodiment, the beam filter146substantially reduces the number of clusters having 100 or less atoms or molecules or both. The beam filter may comprise a magnet assembly for imposing a magnetic field across the GCIB128to aid in the filtering process.

Referring still toFIG. 5, a beam gate148is disposed in the path of GCIB128in the ionization/acceleration chamber106. Beam gate148has an open state in which the GCIB128is permitted to pass from the ionization/acceleration chamber106to the processing chamber108to define process GCIB128A, and a closed state in which the GCIB128is blocked from entering the processing chamber108. A control cable conducts control signals from control system190to beam gate148. The control signals controllably switch beam gate148between the open or closed states.

A substrate152, which may be a wafer or semiconductor wafer, a flat panel display (FPD), a liquid crystal display (LCD), or other substrate to be processed by GCIB processing, is disposed in the path of the process GCIB128A in the processing chamber108. Because most applications contemplate the processing of large substrates with spatially uniform results, a scanning system may be desirable to uniformly scan the process GCIB128A across large areas to produce spatially homogeneous results.

An X-scan actuator160provides linear motion of the substrate holder150in the direction of X-scan motion (into and out of the plane of the paper). A Y-scan actuator162provides linear motion of the substrate holder150in the direction of Y-scan motion164, which is typically orthogonal to the X-scan motion. The combination of X-scanning and Y-scanning motions translates the substrate152, held by the substrate holder150, in a raster-like scanning motion through process GCIB128A to cause a uniform (or otherwise programmed) irradiation of a surface of the substrate152by the process GCIB128A for processing of the substrate152.

The substrate holder150disposes the substrate152at an angle with respect to the axis of the process GCIB128A so that the process GCIB128A has an angle of beam incidence166with respect to a substrate152surface. The angle of beam incidence166may be 90 degrees or some other angle, but is typically 90 degrees or near 90 degrees. During Y-scanning, the substrate152and the substrate holder150move from the shown position to the alternate position “A” indicated by the designators152A and150A, respectively. Notice that in moving between the two positions, the substrate152is scanned through the process GCIB128A, and in both extreme positions, is moved completely out of the path of the process GCIB128A (over-scanned). Though not shown explicitly inFIG. 5, similar scanning and over-scan is performed in the (typically) orthogonal X-scan motion direction (in and out of the plane of the paper).

A beam current sensor180may be disposed beyond the substrate holder150in the path of the process GCIB128A so as to intercept a sample of the process GCIB128A when the substrate holder150is scanned out of the path of the process GCIB128A. The beam current sensor180is typically a Faraday cup or the like, closed except for a beam-entry opening, and is typically affixed to the wall of the vacuum vessel102with an electrically insulating mount182.

As shown inFIG. 5, control system190connects to the X-scan actuator160and the Y-scan actuator162through electrical cable and controls the X-scan actuator160and the Y-scan actuator162in order to place the substrate152into or out of the process GCIB128A and to scan the substrate152uniformly relative to the process GCIB128A to achieve desired processing of the substrate152by the process GCIB128A. Control system190receives the sampled beam current collected by the beam current sensor180by way of an electrical cable and, thereby, monitors the GCIB and controls the GCIB dose received by the substrate152by removing the substrate152from the process GCIB128A when a predetermined dose has been delivered.

In the embodiment shown inFIG. 6, the GCIB processing system100′ can be similar to the embodiment ofFIG. 5and further comprise a X-Y positioning table253operable to hold and move a substrate252in two axes, effectively scanning the substrate252relative to the process GCIB128A. For example, the X-motion can include motion into and out of the plane of the paper, and the Y-motion can include motion along direction264.

The process GCIB128A impacts the substrate252at a projected impact region286on a surface of the substrate252, and at an angle of beam incidence266with respect to the surface of substrate252. By X-Y motion, the X-Y positioning table253can position each portion of a surface of the substrate252in the path of process GCIB128A so that every region of the surface may be made to coincide with the projected impact region286for processing by the process GCIB128A. An X-Y controller262provides electrical signals to the X-Y positioning table253through an electrical cable for controlling the position and velocity in each of X-axis and Y-axis directions. The X-Y controller262receives control signals from, and is operable by, control system190through an electrical cable. X-Y positioning table253moves by continuous motion or by stepwise motion according to conventional X-Y table positioning technology to position different regions of the substrate252within the projected impact region286. In one embodiment, X-Y positioning table253is programmably operable by the control system190to scan, with programmable velocity, any portion of the substrate252through the projected impact region286for GCIB processing by the process GCIB128A.

The substrate holding surface254of positioning table253is electrically conductive and is connected to a dosimetry processor operated by control system190. An electrically insulating layer255of positioning table253isolates the substrate252and substrate holding surface254from the base portion260of the positioning table253. Electrical charge induced in the substrate252by the impinging process GCIB128A is conducted through substrate252and substrate holding surface254, and a signal is coupled through the positioning table253to control system190for dosimetry measurement. Dosimetry measurement has integrating means for integrating the GCIB current to determine a GCIB processing dose. Under certain circumstances, a target-neutralizing source (not shown) of electrons, sometimes referred to as electron flood, may be used to neutralize the process GCIB128A. In such case, a Faraday cup (not shown, but which may be similar to beam current sensor180inFIG. 5) may be used to assure accurate dosimetry despite the added source of electrical charge, the reason being that typical Faraday cups allow only the high energy positive ions to enter and be measured.

In operation, the control system190signals the opening of the beam gate148to irradiate the substrate252with the process GCIB128A. The control system190monitors measurements of the GCIB current collected by the substrate252in order to compute the accumulated dose received by the substrate252. When the dose received by the substrate252reaches a predetermined dose, the control system190closes the beam gate148and processing of the substrate252is complete. Based upon measurements of the GCIB dose received for a given area of the substrate252, the control system190can adjust the scan velocity in order to achieve an appropriate beam dwell time to treat different regions of the substrate252.

Alternatively, the process GCIB128A may be scanned at a constant velocity in a fixed pattern across the surface of the substrate252; however, the GCIB intensity is modulated (may be referred to as Z-axis modulation) to deliver an intentionally non-uniform dose to the sample. The GCIB intensity may be modulated in the GCIB processing system100′ by any of a variety of methods, including varying the gas flow from a GCIB source supply; modulating the ionizer122by either varying a filament voltage VFor varying an anode voltage VA; modulating the lens focus by varying lens voltages VL1and/or VL2; or mechanically blocking a portion of the GCIB with a variable beam block, adjustable shutter, or variable aperture. The modulating variations may be continuous analog variations or may be time modulated switching or gating.

The processing chamber108may further include an in-situ metrology system. For example, the in-situ metrology system may include an optical diagnostic system having an optical transmitter280and optical receiver282configured to illuminate substrate252with an incident optical signal284and to receive a scattered optical signal288from substrate252, respectively. The optical diagnostic system comprises optical windows to permit the passage of the incident optical signal284and the scattered optical signal288into and out of the processing chamber108. Furthermore, the optical transmitter280and the optical receiver282may comprise transmitting and receiving optics, respectively. The optical transmitter280receives, and is responsive to, controlling electrical signals from the control system190. The optical receiver282returns measurement signals to the control system190.

The in-situ metrology system may comprise any instrument configured to monitor the progress of the GCIB processing. According to one embodiment, the in-situ metrology system may constitute an optical scatterometry system. The scatterometry system may include a scatterometer, incorporating beam profile ellipsometry (ellipsometer) and beam profile reflectometry (reflectometer), commercially available from Therma-Wave, Inc. (1250 Reliance Way, Fremont, Calif. 94539) or Nanometrics, Inc. (1550 Buckeye Drive, Milpitas, Calif. 95035).

For instance, the in-situ metrology system may include an integrated Optical Digital Profilometry (iODP) scatterometry module configured to measure process performance data resulting from the execution of a treatment process in the GCIB processing system100′. The metrology system may, for example, measure or monitor metrology data resulting from the treatment process. The metrology data can, for example, be utilized to determine process performance data that characterizes the treatment process, such as a process rate, a relative process rate, a feature profile angle, a critical dimension, a feature thickness or depth, a feature shape, etc. For example, in a process for directionally depositing material on a substrate, process performance data can include a critical dimension (CD), such as a top, middle or bottom CD in a feature (i.e., via, line, etc.), a feature depth, a material thickness, a sidewall angle, a sidewall shape, a deposition rate, a relative deposition rate, a spatial distribution of any parameter thereof, a parameter to characterize the uniformity of any spatial distribution thereof, etc. Operating the X-Y positioning table253via control signals from control system190, the in-situ metrology system can map one or more characteristics of the substrate252.

In the embodiment shown inFIG. 7, the GCIB processing system100″ can be similar to the embodiment ofFIG. 5and further comprise a pressure cell chamber350positioned, for example, at or near an outlet region of the ionization/acceleration chamber106. The pressure cell chamber350comprises an inert gas source352configured to supply a background gas to the pressure cell chamber350for elevating the pressure in the pressure cell chamber350, and a pressure sensor354configured to measure the elevated pressure in the pressure cell chamber350.

The pressure cell chamber350may be configured to modify the beam energy distribution of GCIB128to produce a modified processing GCIB128A′. This modification of the beam energy distribution is achieved by directing GCIB128along a GCIB path through an increased pressure region within the pressure cell chamber350such that at least a portion of the GCIB traverses the increased pressure region. The extent of modification to the beam energy distribution may be characterized by a pressure-distance integral along the at least a portion of the GCIB path, where distance (or length of the pressure cell chamber350) is indicated by path length (d). When the value of the pressure-distance integral is increased (either by increasing the pressure and/or the path length (d)), the beam energy distribution is broadened and the peak energy is decreased. When the value of the pressure-distance integral is decreased (either by decreasing the pressure and/or the path length (d)), the beam energy distribution is narrowed and the peak energy is increased. Further details for the design of a pressure cell may be determined from U.S. Pat. No. 7,060,989, entitled “Method and apparatus for improved processing with a gas-cluster ion beam”; the content of which is incorporated herein by reference in its entirety.

Control system190comprises a microprocessor, memory, and a digital I/O port capable of generating control voltages sufficient to communicate and activate inputs to GCIB processing system100(or100′,100″), as well as monitor outputs from GCIB processing system100(or100′,100″). Moreover, control system190can be coupled to and can exchange information with vacuum pumping systems170A,170B, and170C, first gas source111, second gas source112, first gas control valve113A, second gas control valve113B, beam electronics130, beam filter146, beam gate148, the X-scan actuator160, the Y-scan actuator162, and beam current sensor180. For example, a program stored in the memory can be utilized to activate the inputs to the aforementioned components of GCIB processing system100according to a process recipe in order to perform a GCIB process on substrate152.

However, the control system190may be implemented as a general purpose computer system that performs a portion or all of the microprocessor based processing steps of the invention in response to a processor executing one or more sequences of one or more instructions contained in a memory. Such instructions may be read into the controller memory from another computer readable medium, such as a hard disk or a removable media drive. One or more processors in a multi-processing arrangement may also be employed as the controller microprocessor to execute the sequences of instructions contained in main memory. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.

The control system190can be used to configure any number of processing elements, as described above, and the control system190can collect, provide, process, store, and display data from processing elements. The control system190can include a number of applications, as well as a number of controllers, for controlling one or more of the processing elements. For example, control system190can include a graphic user interface (GUI) component (not shown) that can provide interfaces that enable a user to monitor and/or control one or more processing elements.

Control system190can be locally located relative to the GCIB processing system100(or100′,100″), or it can be remotely located relative to the GCIB processing system100(or100′,100″). For example, control system190can exchange data with GCIB processing system100using a direct connection, an intranet, and/or the Internet. Control system190can be coupled to an intranet at, for example, a customer site (i.e., a device maker, etc.), or it can be coupled to an intranet at, for example, a vendor site (i.e., an equipment manufacturer). Alternatively or additionally, control system190can be coupled to the Internet. Furthermore, another computer (i.e., controller, server, etc.) can access control system190to exchange data via a direct connection, an intranet, and/or the Internet.

Substrate152(or252) can be affixed to the substrate holder150(or substrate holder250) via a clamping system (not shown), such as a mechanical clamping system or an electrical clamping system (e.g., an electrostatic clamping system). Furthermore, substrate holder150(or250) can include a heating system (not shown) or a cooling system (not shown) that is configured to adjust and/or control the temperature of substrate holder150(or250) and substrate152(or252).

Vacuum pumping systems170A,170B, and170C can include turbo-molecular vacuum pumps (TMP) capable of pumping speeds up to about 5000 liters per second (and greater) and a gate valve for throttling the chamber pressure. In conventional vacuum processing devices, a 1000 to 3000 liter per second TMP can be employed. TMPs are useful for low pressure processing, typically less than about 50 mTorr. Although not shown, it may be understood that pressure cell chamber350may also include a vacuum pumping system. Furthermore, a device for monitoring chamber pressure (not shown) can be coupled to the vacuum vessel102or any of the three vacuum chambers104,106,108. The pressure-measuring device can be, for example, a capacitance manometer or ionization gauge.

Referring now toFIG. 8, a section300of a gas cluster ionizer (122,FIGS. 5,6and7) for ionizing a gas cluster jet (gas cluster beam118,FIGS. 5,6and7) is shown. The section300is normal to the axis of GCIB128. For typical gas cluster sizes (2000 to 15000 atoms), clusters leaving the skimmer aperture (120,FIGS. 5,6and7) and entering an ionizer (122,FIGS. 5,6and7) will travel with a kinetic energy of about 130 to 1000 electron volts (eV). At these low energies, any departure from space charge neutrality within the ionizer122will result in a rapid dispersion of the jet with a significant loss of beam current.FIG. 8illustrates a self-neutralizing ionizer. As with other ionizers, gas clusters are ionized by electron impact. In this design, thermo-electrons (seven examples indicated by310) are emitted from multiple linear thermionic filaments302a,302b, and302c(typically tungsten) and are extracted and focused by the action of suitable electric fields provided by electron-repeller electrodes306a,306b, and306cand beam-forming electrodes304a,304b, and304c. Thermo-electrons310pass through the gas cluster jet and the jet axis and then strike the opposite beam-forming electrode304bto produce low energy secondary electrons (312,314, and316indicated for examples).

Though (for simplicity) not shown, linear thermionic filaments302band302calso produce thermo-electrons that subsequently produce low energy secondary electrons. All the secondary electrons help ensure that the ionized cluster jet remains space charge neutral by providing low energy electrons that can be attracted into the positively ionized gas cluster jet as required to maintain space charge neutrality. Beam-forming electrodes304a,304b, and304care biased positively with respect to linear thermionic filaments302a,302b, and302cand electron-repeller electrodes306a,306b, and306care negatively biased with respect to linear thermionic filaments302a,302b, and302c. Insulators308a,308b,308c,308d,308e, and308felectrically insulate and support electrodes304a,304b,304c,306a,306b, and306c. For example, this self-neutralizing ionizer is effective and achieves over 1000 micro Amps argon GCIBs.

Alternatively, ionizers may use electron extraction from plasma to ionize clusters. The geometry of these ionizers is quite different from the three filament ionizer described above but the principles of operation and the ionizer control are very similar. Referring now toFIG. 9, a section400of a gas cluster ionizer (122,FIGS. 5,6and7) for ionizing a gas cluster jet (gas cluster beam118,FIGS. 5,6and7) is shown. The section400is normal to the axis of GCIB128. For typical gas cluster sizes (2000 to 15000 atoms), clusters leaving the skimmer aperture (120,FIGS. 5,6and7) and entering an ionizer (122,FIGS. 5,6and7) will travel with a kinetic energy of about 130 to 1000 electron volts (eV). At these low energies, any departure from space charge neutrality within the ionizer122will result in a rapid dispersion of the jet with a significant loss of beam current.FIG. 9illustrates a self-neutralizing ionizer. As with other ionizers, gas clusters are ionized by electron impact.

The ionizer includes an array of thin rod anode electrodes452that is supported and electrically connected by a support plate (not shown). The array of thin rod anode electrodes452is substantially concentric with the axis of the gas cluster beam (e.g., gas cluster beam118,FIGS. 5,6and7). The ionizer also includes an array of thin rod electron-repeller rods458that is supported and electrically connected by another support plate (not shown). The array of thin rod electron-repeller electrodes458is substantially concentric with the axis of the gas cluster beam (e.g., gas cluster beam118,FIGS. 5,6and7). The ionizer further includes an array of thin rod ion-repeller rods464that is supported and electrically connected by yet another support plate (not shown). The array of thin rod ion-repeller electrodes464is substantially concentric with the axis of the gas cluster beam (e.g., gas cluster beam118,FIGS. 5,6and7).

Energetic electrons are supplied to a beam region444from a plasma electron source470. The plasma electron source470comprises a plasma chamber472within which plasma is formed in plasma region442. The plasma electron source470further comprises a thermionic filament476, a gas entry aperture426, and a plurality of extraction apertures480. The thermionic filament476is insulated from the plasma chamber470via insulator477. As an example, the thermionic filament476may include a tungsten filament having one-and-a-half turns in a “pigtail” configuration.

The section400of the gas cluster ionizer comprises an electron-acceleration electrode488having plural apertures482. Additionally, the section400comprises an electron-deceleration electrode490having plural apertures484. The plural apertures482, the plural apertures484, and the plural extraction apertures480are all aligned from the plasma region442to the beam region444.

Plasma forming gas, such as a noble gas, is admitted to the plasma chamber472through gas entry aperture426. An insulate gas feed line422provides pressurized plasma forming gas to a remotely controllable gas valve424that regulates the admission of plasma forming gas to the plasma chamber472.

A filament power supply408provides filament voltage (VF) for driving current through thermionic filament476to stimulate thermo-electron emission. Filament power supply408controllably provides about 140 to 200 A (amps) at 3 to 5 V (volts). An arc power supply410controllably provides an arc voltage (VA) to bias the plasma chamber472positive with respect to the thermionic filament476. Arc power supply410is typically operated at a fixed voltage, typically about 35 V, and provides means for accelerating the electrons within the plasma chamber472for forming plasma. The filament current is controlled to regulate the arc current supplied by the arc power supply410. Arc power supply410is capable of providing up to 5 A arc current to the plasma arc.

Electron deceleration electrode490is biased positively with respect to the plasma chamber472by electron bias power supply412. Electron bias power supply412provides bias voltage (VB) that is controllably adjustable over the range of from 30 to 400 V. Electron acceleration electrode488is biased positively with respect to electron deceleration electrode490by electron extraction power supply416. Electron extraction power supply416provides electron extraction voltage (VEE) that is controllable in the range from 20 to 250 V. An acceleration power supply420supplies acceleration voltage (VACC) to bias the array of thin rod anode electrodes452and electron deceleration electrode490positive with respect to earth ground. VACCis the acceleration potential for gas cluster ions produced by the gas cluster ionizer shown in section400and is controllable and adjustable in the range from 1 to 100 kV. An electron repeller power supply414provides electron repeller bias voltage (VER) for biasing the array of thin rod electron-repeller electrodes458negative with respect to VACC. VERis controllable in the range of from 50 to 100 V. An ion repeller power supply418provides ion repeller bias voltage (VIR) to bias the array of thin rod ion-repeller electrodes464positive with respect to VACC. VIRis controllable in the range of from 50 to 150V.

A fiber optics controller430receives electrical control signals on cable434and converts them to optical signals on control link432to control components operating at high potentials using signals from a grounded control system. The fiber optics control link432conveys control signals to remotely controllable gas valve424, filament power supply408, arc power supply410, electron bias power supply412, electron repeller power supply414, electron extraction power supply416, and ion repeller power supply418.

For example, the ionizer design may be similar to the ionizer described in U.S. Pat. No. 7,173,252, entitled “Ionizer and method for gas-cluster ion-beam formation”; the content of which is incorporated herein by reference in its entirety.

The gas cluster ionizer (122,FIGS. 5,6and7) may be configured to modify the beam energy distribution of GCIB128by altering the charge state of the GCIB128. For example, the charge state may be modified by adjusting an electron flux, an electron energy, or an electron energy distribution for electrons utilized in electron collision-induced ionization of gas clusters.

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.