1. Field of the Invention
Embodiments of the disclosure provided herein generally relate to apparatus and methods for planarizing a non-uniform surface topography found on a surface of a substrate.
2. Description of the Related Art
Integrated circuits are typically formed on substrates, particularly silicon wafers, by the sequential deposition of conductive, semiconducting or insulating layers. After each layer is deposited, it is etched to create circuitry features. As a series of layers are sequentially deposited and etched, the outer or uppermost surface of the substrate, i.e., the exposed surface of the substrate, becomes increasingly non-planar.
Chemical mechanical polishing is one accepted method of planarization. This planarization method typically requires that the substrate be mounted on a carrier or polishing head with the exposed surface of the substrate being placed against a rotating polishing pad or moving polishing belt that has a polishing slurry disposed thereon. The carrier head provides a controllable motion relative to the polishing pad and applies a load (i.e., pressure) to the substrate to cause the removal of a portion of an exposed layer on the substrate by mechanical action created between the substrate and the polishing pad. The polishing slurry, which will generally include at least one chemically-reactive agent (e.g., acids, bases or even deionized water for oxide polishing) and abrasive particles (e.g., silicon dioxide for oxide polishing), is supplied to the surface of the polishing pad and substrate during the CMP process to help remove a portion of the substrate by mechanical and chemical action.
In applying conventional planarization techniques, such as CMP, it is extremely difficult to achieve a high degree of surface uniformity, particularly across a surface extending from a dense array of features, for example copper lines, bordered by an open field. In planarizing the substrate surface using a CMP process, undesirable erosion and dishing typically occur, decreasing the degree of surface uniformity or planarity, and challenging the depth of focus limitations of conventional photolithographic techniques, particular with respect to achieving submicron dimensions, such as about 0.25 micron and below. Dishing is defined as a difference in height between the height of the sidewalls of a feature formed in a dielectric layer (e.g., oxide layer) and the material disposed within the feature (e.g., copper (Cu) (interconnect applications), silicon dioxide (STI applications)) within the dense array. Erosion is defined as the height differential between the oxide in the open field and the height of the oxide within the dense array. Dishing and erosion formation are the most important parameters in evaluating the effectiveness of a planarization process.
The demand for planarization processes that can be performed on ultrathin layers, mechanically fragile layers (e.g., low-k materials and structures) and on layers that contain toxic elements (e.g., arsenic (As)) has increased over the years, due to the shrinkage in device size and the need for exotic materials to perform certain tailored functions in an electronic device. Due to the mechanical nature of the CMP process, the planarization of thin and fragile layers has become a significant challenge, especially for semiconductor devices that contain low-k porous or air-gap containing structures. Further, in CMP applications that generate toxic byproducts or toxic waste, due the presence of toxic materials in the polished layer, such as indium gallium arsenide (InGaAs) materials, gallium arsenide (GaAs) materials, the handling of the substrates and contaminated system components becomes much more of a safety and/or cost of consumable parts issue.
Therefore, there is a need for a method and apparatus for planarizing a surface of a substrate that solves the problems described above. There is also a need for a planarization processes that can planarize the surface of the substrate without damaging the underlying layers, and also not expose maintenance personnel to toxic byproducts or toxic waste.
The present disclosure generally includes apparatus and methods for planarizing a surface of a substrate using a plasma modification process. A process of plasma planarizing a surface of a substrate generally includes the removal and/or redistribution of a portion of an exposed surface of the substrate by use of an energetic particle beam while the substrate is disposed within a particle beam modification apparatus. In some embodiments, the planarization of a portion of an exposed surface of a substrate may be performed by use of a particle beam modification process that is performed in a sub-atmospheric pressure processing environment. The particle beam modification process may include the delivery of a charged particle beam that includes a spatially localized group of energetic particles (e.g., charged particles and/or neutrals) that are directed towards a surface of a substrate for a desired period of time. In some cases, the particle beam modification process may include the delivery of a charged particle beam that includes a spatially localized group of electrically charged particles that are directed towards a surface of a substrate.
Embodiments of the disclosure may provide an apparatus for planarization of a surface on a substrate, comprising a substrate support having a substrate supporting surface, a plasma generation source, and a beam extraction assembly. The plasma generation source assembly is configured to ionize a process gas. The beam extraction assembly may comprise a first electrode having a first aperture that is positioned to extract at least a portion of the charged particles formed in the plasma generation region, a second electrode having a second aperture that is positioned to receive a flow of the charged particles that passed through the first aperture. The extraction of the charged particles is done by electric fields generated by the electrodes positioned in the beam extraction assembly. The properties of the extracted charged particles depend on the geometry of the plasma boundary and relative biases applied to the components found in the beam extraction assembly. A first power source is generally configured to electrically bias the second electrode to increase the kinetic energy of the charged particles that have passed through the first aperture. The first and second apertures are positioned to direct the flow of the charged particles to the surface of the substrate during processing.
Embodiments of the disclosure may further provide an apparatus for modifying a surface of a substrate, comprising a substrate support having a substrate supporting surface, wherein a first direction is perpendicular to the substrate supporting surface, a first beam extraction assembly configured to simultaneously generate a first particle beam that exits the first beam extraction assembly in a second direction, wherein the first particle beam is directed towards the substrate supporting surface and the second direction is at a first grazing angle relative to the first direction and a second particle beam that exits the first beam extraction assembly in a third direction, wherein the second particle beam is directed towards the substrate supporting surface and the third direction is at the first grazing angle or a second grazing angle relative to the first direction, and an actuator that is configured to translate the substrate supporting surface relative to the first and the second particle beams.
Embodiments of the disclosure may further provide a method of planarizing a surface of a substrate in a processing region of a processing chamber, comprising delivering a first particle beam from a beam extraction assembly towards a substrate disposed on a substrate supporting surface of a substrate support, wherein the delivered first particle beam is provided in a first direction that is at a first grazing angle relative to a second direction which is perpendicular to the substrate supporting surface, delivering a second particle beam from the beam extraction assembly towards the substrate supporting surface, wherein the delivered second particle beam is provided in a third direction that is at the first grazing angle or a second grazing angle relative to the second direction, and moving the substrate relative to the first and second particle beams, or moving the first and second particle beams relative to the substrate, to reduce the non-planarity of a non-planar surface formed on the substrate.
Embodiments of the disclosure may further provide a system for planarizing a surface of a substrate, comprising a transfer chamber having a transfer region, a first process chamber that is coupled to the transfer chamber, a second process chamber that is coupled to the transfer chamber, wherein the second process chamber configured to deposit a layer on the substrate, and a substrate transfer robot disposed in the transfer region, and configured to load and unload substrates disposed in the first processing chamber and the second processing chamber. The first process chamber may comprise a substrate support having a substrate supporting surface, wherein a first direction is perpendicular to the supporting surface, a first beam extraction assembly configured to simultaneously generate a first particle beam that exits the first beam extraction assembly in a second direction, wherein the first particle beam is directed towards the substrate supporting surface and the second direction is at a first grazing angle relative to the first direction, and a second particle beam that exits the first beam extraction assembly in a third direction, wherein the second particle beam is directed towards the substrate supporting surface and the third direction is at the first grazing angle or a second grazing angle relative to the first direction, and an actuator that is configured to translate the substrate supporting surface of the substrate support relative to the first and the second particle beams.
Embodiments of the disclosure may further provide a method of modifying a surface of a substrate in a processing region of a processing chamber, comprising delivering a first particle beam from a beam extraction assembly towards a substrate disposed on a substrate supporting surface of a substrate support, wherein the delivered first particle beam is provided in a first direction that is at a first grazing angle relative to a second direction which is perpendicular to the substrate supporting surface, moving the substrate relative to the first particle beam, or moving the first particle beam relative to the substrate, to reduce the non-planarity of a non-planar surface formed on the substrate, and delivering a etching gas to the non-planar surface of the substrate while substrate is moved relative to the delivered first particle beam.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
Embodiments of the disclosure provided herein include apparatus and methods for modifying a surface of a substrate using a plasma modification process. The plasma modification process may include a plasma planarization process that generally includes the removal and/or redistribution of a portion of an exposed surface of the substrate by use of one or more energetic particle beams while the substrate is disposed within a particle beam generation apparatus. Embodiments of the disclosure may also provide a plasma modification process that includes one or more pre-planarization processing steps and/or one or more post-planarization processing steps that are all performed within one processing system. Some embodiments of the present disclosure may provide apparatus and methods for planarizing a surface of a substrate by performing all of the plasma modification processes within either the same processing chamber, the same processing system or within processing chambers found in two or more processing systems.
In some embodiments, the planarization of a portion of an exposed surface of a substrate may be performed by use of a particle beam modification process that is performed in a sub-atmospheric pressure processing environment. In general, a plasma modification process includes performing one or more steps that make an outer surface of a substrate relatively flat and/or smooth. In some embodiments, the modification process is used to remove an amount of deposited material overburden found on the surface of the substrate, while also planarizing the surface of the substrate. The particle beam modification process may include the delivery of one or more energetic particle beams that includes a spatially localized group of energetic particles that are directed towards and moved relative to a surface of a substrate for a desired period of time. The particles found in the formed one or more energetic particle beams may have approximately the same kinetic energy and are directed towards the surface of the substrate from a particle beam to help remove material and/or planarize the exposed surface of the substrate. In some cases, the particle beam modification process may include the delivery of a charged particle beam that includes a spatially localized group of electrically charged particles that are directed towards a surface of a substrate. The processed substrate may include one or more exposed regions that contain a conductive material, a semiconductive material and/or a dielectric material.
The particle beam modification process generally includes the delivery of at least one energetic particle beam, hereafter particle beam 205, to the non-planar surface 201A of a device structure 200 from a beam extraction assembly 270 to remove material and/or planarize the exposed surface of the substrate. In general, as is discussed further below, the delivered particle beam(s) 205 are used to modify the surface of the substrate and may include charged particles and/or uncharged particles (e.g., neutrals and/or radicals). The particle beam modification process is generally performed in a moderate to low pressure environment within the processing region 220, such as at a processing pressure of between about 0.01 mTorr and about 1 Torr.
The particle beam modification process may include the delivery of one or more particle beams 205 to remove and/or redistribute portions of the non-planar surface 201A by use of a purely physical material planarization process, or in some cases by use of both a physical and a chemical material planarization process. The physical component of particle beam modification process generally includes the energetic bombardment of a portion of the surface of the substrate, whereby the energetic particles in the particle beam 205, which are generated by the beam extraction assembly 270, cause material on the surface of the substrate to be dislodged and/or ejected therefrom, as shown by arrows “B” in
Typically, the higher the mass of the atoms and/or molecules that form the energetic particles in the particle beam 205, the greater the ability of the particle beam 205 to physically remove material from the surface of the substrate. The term “sputtering” is often used to describe the physical component of the particle beam modification process, and the term “sputter yield” is generally used herein to describe the ability of an energetic gas atom, or molecule, in the particle beam to remove atoms from the surface of the substrate. The higher the sputter yield, which is typically dependent on the mass and the kinetic energy of the particles (e.g., atom or molecule) in the beam, the more effective the energetic atoms are at removing material from the surface of the substrate. In some configurations, the particle beam comprises energetic ions and/or neutrals formed from a plasma that contains one or more gas atoms, such as argon (Ar), neon (Ne), krypton (Kr), xenon (Xe), radon (Rn), nitrogen (N), helium (He) and hydrogen (H), and/or molecules, such as nitrogen and hydrogen compounds (NxHy), or a combination of thereof (e.g., Ar/Xe). In some embodiments, the particle beam comprises energetic ions and/or neutrals formed from a plasma that contains molecules formed from gases containing elements such as germanium (Ge), silicon (Si), gallium (Ga), arsenic (As), Iodine (I), or a combination of gas atoms and molecules thereof (e.g., Ar/trimethylgallium (TMG)). In one example, the particle beam 205 comprises an argon ion beam.
Another, factor that can affect the ability of the particle beam 205 to remove and/or redistribute material on the surface of the substrate is the incident angle 210 of the directed particle beam, which is typically measured from a direction that is perpendicular, or normal, to the surface of the device structure 200. In
In general, the chemical material planarization component of the particle beam modification process will include a gas phase or vapor phase chemical interaction of the ions or radicals found in the particle beam 205, or gas phase, vapor phase and/or gas or vapor phase reactive species (e.g., radicals) supplied from the processing environment surrounding the particle beam 205, with the material at the surface of the substrate. Thus, the chemical interaction of chemical species found in the particle beam 205, or that interact with particle beam 205, is used to help remove and/or redistribute the material on the surface of the substrate by use of a non-physical method. In some cases, the chemical material planarization process may occur by reacting a gas or vapor phase etchant with the surface of the substrate. Therefore, in some embodiments, the particle beam 205 and/or environment surrounding the particle beam 205 comprise an etchant material, such as an etchant gas that contains a halogen gas, such as chlorine (Cl2), fluorine (F2), bromine (Br2) and iodine (I2), and/or molecules, such as ammonia (NH3). In one example, the particle beam 205 comprises chlorine (CI) or fluorine (F) containing ions. In one example, the particle beam 205 comprises an inert gas and an etchant gas, such as a gas mixture that contains argon and fluorine or chlorine. In another example, the particle beam 205 comprises an inert gas and an etchant gas, where the etchant gas may contain fluorine (F2), nitrogen trifluoride (NF), carbon tetrafluoride (CF4), boron trifluoride (BF3), xenon difluoride (XeF2), boron trichloride (BCl2), trifluoromethane (CHF3), hexafluoroethane (C2F6), chlorine (Cl2) or other fluorocarbons or chlorine containing gases. In another example, the particle beam 205 comprises an inert gas and the processing region surrounding the substrate includes an etchant gas, such as fluorine or chlorine.
The beam extraction assembly 270 typically includes a gas source 271, a plasma generation source 272 and an electrode assembly 273. The gas source 271 generally includes one or more sources of gas atoms, gas phase molecules or other vapor delivering sources that are able to provide a process gas that includes gas atoms, molecules, or vapor that when ionized by the plasma generation source 272 can be extracted by the electrode assembly 273 to form part of the particle beam 205.
The plasma generation source 272 generally includes a source of electromagnetic energy that is configured to deliver energy to a plasma generation region to form a plasma therein using the process gas delivered from the gas source 271. In general, the plasma generation source 272 can use one or more plasma generation techniques to form a plasma in the plasma generation region. The plasma generation techniques may include, for example, the delivery of electromagnetic energy to the plasma generation region from a capacitively coupled plasma source, an inductive coupled plasma source, a helicon type source, electron cyclotron resonance (ECR) type source and/or the delivery of microwave energy from a microwave source.
The electrode assembly 273 is generally a device that is used to extract ions generated within the plasma generation region of the plasma generation source 272 to form and deliver one or more energetic particle beams that each include a spatially localized group of energetic particles that are directed towards a surface of a substrate. The one or more energetic particle beams 205 may include a cylindrical shaped beam, a plurality of adjacent or overlapping cylindrical beams, or a ribbon shaped beam (e.g., a continuous rectangular shaped beam). The one or more energetic particle beams 205 can be moved relative to the non-planar surface 201A during processing and/or the substrate can be moved relative to the energetic particle beam 205 during processing to planarize the surface of the substrate. In some embodiments, as will be discussed further below, the electrode assembly 273 includes components that are adapted to adjust the trajectory (e.g., angle 210) of the generated energetic particle beams to the surface of the substrate to compensate for surface morphology variations on the non-planar surface 201A and/or improve the results of the particle beam modification process.
The chamber assembly 315 will also typically include a substrate support assembly 371 that is adapted to support the substrate during processing. In some cases, the substrate support assembly 371 may also include one or more actuators (not shown) that are adapted to translate or rotate the substrate relative to the electrode assembly 273 during processing. In applications that require the substrate 301 to be translated or rotated, some of the driving components, such as an actuator or a motor are positioned outside of the processing region 310 and are coupled to the elements that support the substrate 301 within the processing region 310 using a conventional vacuum feed-through or other similar mechanical device. In some configurations, one or more of the actuators are adapted to position the substrate 301 relative to the electrode assembly 273 so that a desired gap 372, which is measured in the Z-direction in
As noted above, the beam extraction assembly 270 typically includes a gas source 271, a plasma generation source 272 and electrode assembly 273. In one configuration, as illustrated in
Referring to
As noted above, the plasma generation source 272 generally includes a source of electromagnetic energy that is configured to form a plasma 335 in the plasma generation region 332 using the process gas delivered from the one or more gas sources 341. The plasma generation source 272 may include a power source 330 and an antenna 331, which is in electrical communication with the plasma generation region 332. In one non-limiting example, the antenna 331 may be a capacitively coupled electrode that is adapted to generate the plasma 335 in the plasma generation region 332, when radio frequency (RF) energy is delivered from the power source 330 to the antenna 331 during processing.
The electrode assembly 273 may include a beam controller 350 and beam delivery element 322 that are used to extract charged particles formed within the plasma generation region 332 to form and deliver one or more particle beams 205 to a surface of a substrate 301 through one or more apertures 321 that are formed in the beam delivery element 322. The shape of the aperture 321 is formed so that a beam having a desired shape is created by the beam delivery element 322, such as a ribbon shaped or cylindrical shaped beam. In some configurations, the aperture 321 is also positioned and aligned to direct the particle beam 205 to a desired portion or region of the surface of the substrate during processing. The system controller 390 is generally configured to control the generation and delivery of the one or more energetic particle beams 205 by sending commands to the various components found in the beam controller 350 and beam delivery element 322.
The chamber assembly 315 may also include a bias assembly 360 that is in communication with the system controller 390 and is configured to deliver energy to the processing region 310 of the processing chamber 300. The bias assembly 360 generally includes a support electrode 364 and a source 363, which is coupled to ground and can be used to remove any accumulated charge found on the substrate 301 during or after performing the plasma modification process. To remove any residual charge found on the substrate, the source 363 may utilize an AC or high frequency power source (e.g., 2 MHz-200 MHz power source) that is configured to form a plasma over the substrate 301 during one or more phases of the plasma modification process performed in the processing region 310. It is believed that the formed plasma will provide a path to ground that will allow any stored charge in the substrate to be dissipated. In some cases the bias assembly 360 can also be used to help control the trajectory and/or energy of the particle beam 205 that strikes the surface of the substrate 301 during the plasma modification process.
In one configuration, as illustrated in
In operation, the plasma aperture electrode 511, the steering electrodes 513, and the local ground electrode 512 can be independently biased, such that the properties of the particle beam 205, such as particle beam energy (e.g., kinetic energy) and direction, can be controlled. Initially, an optional power source 521 is configured to provide a reference bias on the plasma aperture electrode 511, so that ions found in the plasma 335 can be accelerated towards plasma aperture electrode 511 and/or the steering electrodes 513. Since it may be possible to form positive and negative ions in the plasma 335 the biases applied to the various electrodes may be adjusted accordingly to generate and deliver a particle beam 205 having a desired composition and energy to the surface of the substrate 301.
In some configurations, the plasma aperture electrode 511 is maintained at a negative potential (e.g., DC, AC or RF potential) by the optional power source 521 and thus the plasma potential formed by the plasma generation source 272 is adjusted relative to the plasma aperture electrode 511, so that a ready supply of ions can be generated and sustained in the plasma 335 and allow a portion of the formed ions to be extracted by the relative bias formed between the plasma aperture electrode 511 and the plasma 335. The ions formed in the plasma 335 may enter the aperture 321 formed in the plasma aperture electrode 511 at an initial energy of, for example, about 10 eV to about 5 keV. The energy of the ions entering the aperture 321 formed in the plasma aperture electrode 511 may be adjusted by altering the bias applied to the plasma aperture electrode 511 by the power source 521.
The ions entering the aperture 321, which now form part of the forming particle beam 205, are accelerated (e.g., increased kinetic energy) due to the forward bias applied between the plasma aperture electrode 511 and the steering electrodes 513 by either or both of the power sources 531 and 532. In general, a “forward bias” will include the application of a bias that causes the ions in the particle beam to be accelerated as they pass from the plasma aperture electrode 511 to the local ground electrode 512. In one example, for cases where the ions generated in the plasma 335 have a positive charge the relative bias applied between the plasma aperture electrode 511 and at least one of the steering electrodes 513 may be on the order of a negative 5 to 15 keV, such as about 10 keV.
The energy of the charged particles passing through the slit formed in, or between, the steering electrodes 513 is then affected by the relative bias created between the steering electrodes 513 and the local ground electrode 512. Typically, the relative bias formed between the steering electrodes 513 and the local ground electrode 512 will be a decelerating field. Also, in general, it is desirable for the local ground electrode 512 and the substrate 301 to be maintained at the same potential. In one example, the local ground electrode 512 and the substrate 301 are maintained a ground potential. Typically, one or more conductive elements 552 formed in the substrate support assembly 371 are used to control the relative bias generated between the substrate 301 and the local ground electrode 512. The plurality of conductive elements 552, which may be disposed in a dielectric material 551 within the substrate support assembly 371, may be in electric communication with a surface of the substrate 301. In one example, the conductive elements 552 may include metallic elements formed on a substrate supporting surface of the substrate support assembly 371, or are formed by use of separate conductive lift pins or other chamber elements found within the processing chamber 300.
Referring back to
Upon reaching the slit, or aperture, formed in the local ground electrode 512, the particle beam 205 may have an energy of, for example, approximately 0.1 keV and about 20 keV. In another example, the particle beam 205 energy may be between about 5 keV and about 10 keV. The particles exiting the slit, or aperture, formed in the local ground electrode 512 will then flow to and strike the exposed surface of the substrate so as to cause a modification to the surface of the substrate (e.g., planarize the surface of the substrate). In one case, the particles in the formed particle beam 205 “drift” at the kinetic energy achieved at the exit of the slit formed in the local ground electrode 512 to the surface of the substrate. In another case, the source 363 in the bias assembly 360 is used to alter the energy of the ions in the particle beam 205 by applying a bias to the support electrode 364 (e.g., apply a DC or RF bias potential).
In some embodiments, the electrode assembly 273 may also include an electric field control assembly 540 that is adapted to actively or passively control the shape of the field lines generated by the beam delivery element 322. Control of the shape of the field lines generated by the components within the beam delivery element 322 can be useful to effectively control the trajectory of the charged particles formed in the particle beam 205. In one configuration, the electric field control assembly 540 includes a control element 542 that may include a layer of a dielectric material, semiconductor material or conductive material that is positioned between the components found within the beam delivery element 322 and the substrate 301 to alter the shape of the electric field lines that extend through the processing region 310 of the process chamber 300. The control element 542 may be positioned adjacent to or near the various components found within the beam delivery element 322.
In one configuration, the electric field control assembly 540 includes a control element 542 that is electrically coupled to one or more of the steering electrodes 513 (
In another configuration, the electric field control assembly 540 includes a control element 542 that is separately biased by a power source 541 to actively control the shape of the electric field lines that extend through the processing region 310 by use of commands sent from the system controller 390. In this configuration, the control element 542 is separately biased to a potential that may be different than the potential applied to the steering electrode(s) 514, 515 to alter the shape of the electric field lines that extend through the processing region 310. In case where the extracted ions have a positive charge the bias applied to the control element 542 will have a negative potential, and where the extracted ions have a negative charge the bias applied to the control element 542 may have a positive potential.
In some embodiments, a bias can be applied to one or more of the steering electrodes 513 to alter the trajectory of the particle beam 205 in a desired direction.
In one configuration of the electrode assembly 273, as illustrated in
In some configurations of the processing chamber 300, an plasma modification process endpoint detection technique is used to determine when the planarization process is complete. In one configuration, the endpoint detection technique includes an optical endpoint monitoring system 376 that is able to detect when a layer on the surface of the substrate has been removed or when a property of the material found within the processing region 310 has changed due to the completion of the plasma modification process. In one example, the property of the material within processing region may change as the gas phase concentration in the processing region changes after an upper most layer has been substantially removed from the substrate and a next underlying layer on the substrate is exposed to the particle beam 205. In general, an optical monitoring system that is able to detect an endpoint may include a light source (not shown), a light detector (not shown), and sensing circuitry (not shown) that is used to send and receive signals between a remote controller (e.g., system controller 390) and the light source and a light detector. In one aspect, a method of detecting an endpoint includes performing the plasma modification process on a first layer formed on a substrate, and during processing, obtaining a sequence over time of measured optical spectra with the optical monitoring system. The measured optical spectrum can then be compared with previously stored spectrum and/or other stored parameters that are used to determine the endpoint, which can then be used to decide when to stop the plasma modification process. In another configuration, optical monitoring system is able to detect an endpoint by use of reflectometry process, where the optical monitoring system includes a light source (not shown), a light detector (not shown), and sensing circuitry (not shown) that are used to send and receive signals that are reflected off of the processed surface of the substrate. The measured optical signals used in the reflectometry end point sensing process can then be compared with previously stored data and/or other stored parameters so that the system controller can determine when to stop the plasma modification process.
The system controller 702 may be used to control one or more components found in the processing system. In some configurations, the system controller 702 may form part of the system controller 390, which is discussed above. The system controller 702 is generally designed to facilitate the control and automation of the processing system 700 and typically includes a central processing unit (CPU) (not shown), memory (not shown), and support circuits (or I/O) (not shown). The CPU may be one of any form of computer processors that are used in industrial settings for controlling various system functions, substrate movement, chamber processes, and control support hardware (e.g., sensors, robots, motors, lamps, etc.), and monitor the processes performed in the system (e.g., substrate support temperature, power supply variables, chamber process time, I/O signals, etc.). The memory is connected to the CPU, and may be one or more of a readily available memory, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. Software instructions and data can be coded and stored within the memory for instructing the CPU. The support circuits are also connected to the CPU for supporting the processor in a conventional manner. The support circuits may include cache, power supplies, clock circuits, input/output circuitry, subsystems, and the like. A program (or computer instructions) readable by the system controller 702 determines which tasks are performable on a substrate in one or more of the process chambers and in the processing system 700. Preferably, the program is software readable by the system controller 702 that includes code to perform tasks relating to monitoring, execution and control of the movement, support, and/or positioning of a substrate along with the various process recipe tasks and various chamber process recipe steps being performed in the processing system 700.
The processing system 700 includes a plurality of processing chambers 704, 706, 708, 710 that are coupled to a transfer chamber 712. Each processing chamber 704, 706, 708, 710 may be configured to process one or more substrates 301 at a time. The processing chamber 704, 706, 708, 710 may have the same or different substrate processing capacities. For example, the processing chamber 704 and 706 can simultaneously process six substrates, while processing chambers 708 and 710 may be adapted to process one or more substrates at a time.
The processing system 700 may also include load lock chambers 716 and 724 that are connected to the transfer chamber 712. In one embodiment, the load lock chambers 716 and 724 may also be used as one or more service chambers for providing various functions for processing within the processing system 700, for example, substrate orientation, substrate inspection, heating, cooling, degassing, or the like. The transfer chamber 712 defines a transfer volume 752. A substrate transfer robot 714 is disposed in the transfer volume 752 for transferring substrates 301 among the processing chambers 704, 706, 708, 710, the load lock chambers 716 or 724. The transfer volume 752 is in selective fluid communication with the processing chambers 704, 706, 708, 710, the load lock chambers 716 and 724 via slit valves 744, 746, 748, 750, 742 respectively. In one example, the transfer volume 752 may be maintained at a sub-atmospheric pressure while the substrates are transferred through the processing system 700.
The processing system 700 includes a factory interface 718 connecting one or more pod loaders 722 and the load lock chambers 716 and 724. The load lock chambers 716 and 724 provides a first vacuum interface between the factory interface 718 and the transfer chamber 712, which may be maintained in a vacuum state during processing. Each pod loader 722 is configured to accommodate a cassette 728 for holding and transferring a plurality of substrates. The factory interface 718 includes a Fl robot 720 configured to shuttle substrates between the load lock chambers 716 and 724, and the one or more pod loaders 722.
The substrate transfer robot 714 includes a robot blade 730 for carrying one or more substrates 301 among the processing chambers 704, 706, 708, 710, the load lock chamber 716 and 724, and loading/unloading each chamber.
Each processing chamber 704, 706, 708, 710 may be configured to perform the plasma modification process described herein. However, in one embodiment of the processing system 700, the process chambers 704 and 706 are adapted to perform the plasma modification process on a plurality of substrates using a plurality of beam extraction assembly 270. In one configuration process chambers 708 and 710 may each be adapted to perform one or more preprocessing steps on the substrates 301 before they are inserted into either processing chamber 704 or 706, or post-processing steps on the substrates 301 after they have been processed in either processing chamber 704 or 706. Examples, of the preprocessing or post-processing steps are further described below in conjunction with
In one configuration of the processing system 700, the processing chambers 704 and 706 each include a substrate conveyance assembly 707 that is configured to retain and transport a plurality of substrates 301 that are retained within the processing regions 709 or 715 of the processing chambers 704 or 706, respectively. In one example, each of the substrate conveyance assemblies 707 are adapted to retain six substrates 301 and rotate the substrates 301 about a central axis 711 of the processing chamber 704 or 706 by use of conventional rotational hardware components. The substrate conveyance assembly 707 is thus able to transfer and position the substrates 301 relative to each of the beam extraction assemblies 270 that are positioned to process substrates 301 found in the processing region 709 or 715 of the processing chamber 704 or 706, respectively.
In some configurations, as illustrated in processing chamber 704 in
However, in some embodiments, the particle beam 205 generated by each beam extraction assembly 270 may be rotated or translated relative to the surface of the substrate (e.g., X-Y plane). In this case, an actuator (not shown) that is found within each beam extraction assembly 270 is configured to rotate or translate the beam delivery element 322 (
During a process sequence performed in processing chamber 704, for example, the transfer robot 714 delivers a substrate 301 to an open position on the substrate conveyance assembly 707 and then the substrate conveyance assembly 707 and system controller 702 work together to position the substrate 301 under one of the beam extraction assemblies 270 for processing. The transfer robot 714 may repeat this task of sequentially loading substrates until the all of the positions in the processing chamber 704 have been filled, and then a batch processing plasma modification processing sequence is performed on all of the substrates 301 at one time. After the substrate(s) have been sufficiently processed within the processing chamber 704 the transfer robot 714 is configured to remove the substrate from the processing region 709.
Alternately, in some cases, the transfer robot 714 may insert and remove substrates from the processing chamber 704 as needed, so that a sequentially performed plasma modification process can be performed on each substrate 301 that is serially loaded into the processing chamber 704. In some processing configurations, the substrate conveyance assembly 707 is configured to sequentially position the received substrates under each of the beam extraction assemblies 270 so that at least a portion of the plasma modification processing sequence is performed on the substrate by each of the beam extraction assemblies 270 before the substrate exits the process chamber. In one configuration, each of the beam extraction assemblies 270 within the processing chamber 704 are configured to separately provide the same type of particle beam 205 to the surface of the substrate during the sequential process. In another configuration, two or more of the beam extraction assemblies 270 are each adapted to separately provide a particle beam 205 that has some different processing characteristic, such as beam energy, beam direction, beam composition (e.g., gas ions), or other useful property to the surface of the substrate. In general, the direction of the generated particle beam 205 exiting the beam extraction assemblies 270 can be defined in 3D space, and thus, in one example, can be at least partially defined by the beam angle (e.g., angle 210) and the beam angle relative to the radial position of the substrate conveyance assembly 707.
In some configurations of the processing chambers 704 or 706, the area or region below each of the beam extraction assemblies 270 may be isolated from adjacent beam extraction assemblies 270, so that different processing environments can be maintained below each beam extraction assembly 270. In one configuration, an at least partially enclosed region (e.g., gas curtain or physical walls) is formed around each beam extraction assembly 270, such that each of the substrates 301 can be positioned within the sub-processing region by the substrate conveyance assembly 707 and be separately processed by the beam extraction assembly 270.
The processing chambers 802 and 804 may each include a substrate conveyance assembly 810 that is configured to retain and transport a plurality of substrates 301 that are retained within the processing regions of the processing chamber 802 or 804, respectively. In one example, each of the substrate conveyance assemblies 810 are adapted to retain eight substrates 301 and rotate the substrates 301 about a central axis of the processing chamber 802 or 804 by use of conventional rotational hardware components. The substrate conveyance assembly 810 is thus able to transfer and position the substrates 301 relative to each of the particle beams 205 found in the processing region of the processing chamber 802 or 804.
In some configurations, as illustrated in processing chamber 802 in
Alternately, in some configurations, as illustrated in processing chamber 804 in
In one configuration of the processing system 900, the processing chamber 902 includes a substrate conveyance assembly 904 that is configured to retain and transport a plurality of substrates 301 that are retained within the processing region of the processing chamber 902. The substrate conveyance assemblies 904 is generally adapted to retain groups of substrates 301 and rotate (R1) the groups of substrates 301 about a central axis of the processing chamber 902 by use of conventional rotational hardware components and rotate (R2) each group of substrates relative to the center of a substrate support 905, which supports the group of substrates, by use of conventional rotational hardware components. In some configurations, as illustrated in
As similarly discussed above, each of the beam extraction assemblies 270 within the processing chamber 1000 may be configured to provide the same type of particle beam 205 to the surface of the substrate as the substrate 301 is moved relative to the beam extraction assemblies 270 by use of an actuator 1020. In another configuration, two or more of the beam extraction assemblies 270 are adapted to provide a particle beam 205 that has some different processing characteristic, such as beam energy, beam angle (e.g., angle 210), beam angle relative to the transfer direction of the substrate, beam composition (e.g., gas ions), or other useful property to the surface of the substrate. In some cases, it may be desirable to provide a higher energy and/or higher sputter yielding particle beam 205 to the surface of the substrate by a first beam extraction assembly 270 and then a less aggressive and more smoothing planarization process is preformed by the second and/or third beam extraction assemblies 270.
In one configuration, a series of intermediate conveyors 1122 support and guide the substrates through the various processing chambers. While the conveyor system has been shown with a number of individual conveyors 1118, 1120 and 1122, a single conveyor with a continuous web of material may be used. In one configuration, the conveyors include support rollers 1126 that support and drive the web(s) of material. When individual conveyors 1118, 1120 and 1122 are used, the rollers 1126 may be mechanically driven by a common drive system (not shown) such that they are moved in unison, or individually. The various drives for the rollers 1126, ports 1124 and other system actuators are provided by control signals from a system controller 702, which as discussed above, may include memory 1107, a CPU 1109 and supporting circuits 1111. While in the embodiment illustrated in
In one configuration of the processing system 1100, the processing chamber 1102 is adapted to perform one or more preprocessing steps on a substrate 301 before it is inserted into process chamber 1104 and the process chamber 1110 is adapted to perform one or more post-processing steps on the substrate 301 after it has been processed in at least one of the processing chambers 1104-1108. Examples, of the preprocessing or post-processing steps are further described below in conjunction with
The processing chambers 1104-1108 are each adapted to perform at least a part of the plasma modification process that is described herein. The processing chambers 1104-1108 will each generally include one or more beam extraction assemblies 270 that are configured to deliver one or more particle beams 205 to a surface of a substrate 301. In one example, the processing chambers 1104-1108 include at least one beam extraction assembly 270 that is configured to deliver a particle beam 205 to a surface of the substrate 301 as it is moved relative to the beam extraction assembly 270 by use of a conveyor 1122.
In some embodiments, each of the processes performed in each of the processing chambers 1104-1108 can be isolated from the other processing chambers due to the presence of an enclosure that surrounds the processing regions of each the processing chambers 1104-1108. In some configurations, each of the ports 1124 separating the processing regions of each of the processing chambers can be selectively closed to physically isolate the processing regions of adjacent processing chambers. In one example, a slit valve or a gate valve is mounted at each port 1124 in the processing system 1100 to selectively isolate the processing environments of adjacent processing chambers. In one configuration, each of the processing chambers 1102-1110 each include an exhaust or pumping system 1131-1135, respectively, to control the pressure and/or gas composition with the processing regions of each of the process chambers. Therefore, as similarly discussed above, each of the beam extraction assemblies 270 within the processing chambers 1104-1108 may be configured to provide the same or different type of particle beam 205 or particle beam processing environment as the substrate 301 is moved relative to the beam extraction assemblies 270 by use of the conveyors 1122.
As illustrated in
In one embodiment, the processing sequence 1300, starts at step 1302 in which an optional pre-planarization process is performed on a surface of a substrate. In general, the optional pre-planarization process step 1302 may include the use of a chemical mechanical polishing (CMP) process to remove at least a portion of the material disposed on the surface of the substrate prior to performing the plasma modification process step, or step 1304 on the substrate. The use of an initial CMP process step prior to performing plasma modification processing step 1304 may be useful to help remove some of the variation in the height of the features formed on the surface of an un-planarized substrate. In this case, the subsequent plasma modification processing step 1304 may only provide a fine planarization of the surface of the substrate, or in other words a “fine polishing” of the surface of the substrate.
In one embodiment of the processing sequence 1300, the optional step 1302 may alternately or additionally include a wet or dry chemical cleaning process that is used to remove a portion of the surface of the substrate prior to performing the plasma modification processing step 1304. In one example, an oxide layer or a contaminated layer may be removed from the surface of the substrate by use of one or more reactive species, such as delivering an etching gas or a cleaning solution to a surface of the substrate, to remove a portion of the material from the surface of the substrate.
Next, in step 1304, a plasma modification process is performed on an exposed surface of a substrate to make the outer surface of the substrate relatively flat and/or smooth. As discussed above, the step 1304 may include the delivery of an energetic particle beam that includes a spatially localized group of energetic particles that are directed towards a surface of a substrate for a desired period of time. The plasma modification process may include the simultaneous and/or sequential delivery of a plurality of particle beams 205 to a surface of the substrate. Each of the delivered particle beams may have different processing characteristic, such as beam energy, beam angle, beam composition (e.g., gas ions), or other useful property.
In some embodiments, step 1304 includes the delivery of at least one energetic particle beam to a surface of a substrate in multiple sequential processing steps to planarize the surface of the substrate. As noted above, the multiple sequential processing steps may be performed in a single plasma modification processing chamber or in multiple plasma modification processing chambers. Also, as discussed above, the particle beam modification process performed in step 1304 may include the use of physical and/or chemical material planarization processes performed in a single process step or in one or more of the multiple sequential processing steps.
Referring to
Next, in step 1306, an optional cleaning process is performed on substrate after step 1304 has been performed. In this step, the substrate is cleaned to remove any undesirable materials left over from the prior processing steps. In some configurations, step 1306 includes the delivery of a cleaning gas (e.g., dry cleaning process) to a surface of the substrate in a processing chamber that is disposed on a processing system (e.g., processing systems 700, 800, 900, 1000, 1100 or 1200) that contains a processing chamber that is adapted to perform step 1304. In one example, step 1306 may include the use of a reactive ion etching (RIE) or a plasma assisted dry etching process that is provided to a surface of the substrate to clean and/or remove any residual contamination found on the surface of the substrate. Alternately, step 1306 may include an ex-situ cleaning process that includes the delivery of a wet cleaning solution to a surface of the substrate to remove any undesirable materials from the surface of the substrate. In this case, the substrate may be cleaned using a wet cleaning process in which a cleaning solution, such as a HF-last type cleaning solution, ozonated water cleaning solution, hydrofluoric acid (HF) and hydrogen peroxide (H2O2) solution, DI water, or other suitable cleaning solution. In some embodiments of the processing sequence 1300, step 1306 may be performed after performing step 1308, which is discussed below.
Next, at step 1308, an optional post-planarization process is performed on the substrate after step 1304 has been performed. In one configuration, the optional post-planarization process step 1308 may include the use of a chemical mechanical polishing (CMP) process to remove at least a portion of the material disposed on the surface of the substrate after performing step 1304 on the substrate. The CMP process in this case may be useful to help remove and further planarize some of the features formed on the surface of the substrate. In this case, the plasma modification process completed in step 1304 may provide a rapid and/or partial planarization of the surface of the substrate, and the post-planarization process step 1308 provides the final planarization clean-up of the surface of the substrate. The CMP type post-planarization process step may be used to remove any islands or other unwanted material left on the surface of the substrate leftover from the previous plasma modification process step 1304.
In one embodiment of the processing sequence 1300, the optional step 1308 may alternately or additionally include a deposition process step that is used to “cap” the surface of the substrate after performing the plasma modification processing step 1304. In one example, deposition process may include the deposition of a conductive (e.g., titanium layer, tantalum layer), a semiconductive (e.g., silicon, GaAs, III-V layer) or a dielectric layer (e.g., SiO2, SiN) over the surface of the previously processed surface of the substrate. In some configurations, step 1308 includes the formation of a layer on a surface of the substrate in a processing chamber that is disposed in a processing system (e.g., processing systems 700, 800, 900, 1000, 1100 or 1200) that contains a processing chamber that is adapted to perform step 1304. In some examples, the deposition process may be completed by performing a deposition process in a processing chamber that is configured to perform a plasma enhanced chemical vapor deposition (PECVD) process, low pressure chemical vapor deposition (LPCVD) process, hot wire chemical vapor deposition (HWCVD) process, atomic layer deposition (ALD) process, physical vapor deposition (PVD) process, and/or other similar deposition process.
Embodiments of the disclosure provided herein may thus provide a processing sequence 1300 that includes steps 1302 and 1304, which are discussed above. Some embodiments of the disclosure may provide a processing sequence 1300 that includes steps 1302, 1304 and 1308. Some embodiments of the disclosure may also provide a processing sequence 1300 that includes steps 1304 and 1308. Some embodiments of the disclosure may also provide a processing sequence 1300 that includes steps 1304 and 1306. Some embodiments of the disclosure may also provide a processing sequence 1300 that includes steps 1304, 1306 and 1308. Some embodiments of the disclosure may also provide a processing sequence 1300 that includes steps 1304, 1308 and 1306, which are performed in that processing order. Some embodiments of the disclosure may also provide a processing sequence 1300 that includes steps 1302, 1304, 1306 and 1308, where steps 1306 and 1308 are performed in any desirable processing order. Some embodiments of the disclosure may also provide a processing sequence 1300 that only includes step 1304.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This application claims benefit of both U.S. provisional patent application Ser. No. 61/949,841, filed Mar. 7, 2014, and U.S. provisional patent application Ser. No. 61/989,370, filed May 6, 2014. Both cases in their entirety are hereby incorporated herein by reference.
Number | Date | Country | |
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61949841 | Mar 2014 | US | |
61989370 | May 2014 | US |