Patent Application
20140178583
The present invention relates to thermochromic materials and devices. More particularly, this invention relates to methods and systems for developing thermochromic materials and devices in a combinatorial manner.
Combinatorial processing enables rapid evaluation of, for example, semiconductor and solar processing operations. The systems supporting the combinatorial processing are flexible to accommodate the demands for running the different processes either in parallel, serial or some combination of the two.
Some exemplary processing operations include operations for adding (depositions) and removing layers (etch), defining features, preparing layers (e.g., cleans), conversion of layers or surfaces, doping, etc. Similar processing techniques apply to the manufacture of integrated circuit (IC) semiconductor devices, flat panel displays, optoelectronics devices, data storage devices, magneto electronic devices, magneto optic devices, packaged devices, and the like. As manufacturing processes continue to increase in complexity, improvements, whether in materials, unit processes, or process sequences, are continually being sought for the multi-step processing sequence. However, semiconductor, thin-film-coating, and solar companies conduct research and development (R&D) on full wafer and (glass) substrate processing through the use of split lots, as the conventional deposition systems are designed to support this processing scheme. This approach has resulted in ever escalating R&D costs and the inability to conduct extensive experimentation in a timely and cost effective manner. Combinatorial processing as applied to semiconductor, solar, or energy-efficiency manufacturing operations enables multiple experiments to be performed at one time in a high throughput manner. Equipment for performing the combinatorial processing and characterization must support the efficiency offered through the combinatorial processing operations. The debottlenecking of the R&D efforts involves the above fast processing platforms in combination with throughput-matched characterization and fast automated data capture and analysis, in addition to accelerated lifetime testing and product simulations to allow a fast guidance for subsequent design of experiments to unravel the correlations between materials, processing, equipment, and product performance and durability.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The drawings are not to scale and the relative dimensions of various elements in the drawings are depicted schematically and not necessarily to scale.
The techniques of the present invention can readily be understood by considering the following detailed description in conjunction with the accompanying drawings, in which:
A detailed description of one or more embodiments is provided below along with accompanying figures. The detailed description is provided in connection with such embodiments, but is not limited to any particular example. The scope is limited only by the claims and numerous alternatives, modifications, and equivalents are encompassed. Numerous specific details are set forth in the following description in order to provide a thorough understanding. These details are provided for the purpose of example and the described techniques may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the embodiments has not been described in detail to avoid unnecessarily obscuring the description.
Thermochromic materials, in general, are those that change color due to a change in temperature. Exemplary thermochromic materials include strontium calcium manganese oxide, neodymium nickel oxide, thermochromic tungsten, and fluorine-doped vanadium dioxide, which may be deposited using, for example, physical vapor deposition (PVD) or atomic layer deposition (ALD).
One important factor for the performance of thermochromic coatings is the metal-insulator transition which is dependent on stoichiometry and nanoscale morphology. When the thermochromic materials are to be used in window panels, ideally this transition is tuned to a temperature similar to typical outdoor temperatures. The impact of substrate conditions, deposition and additional processing conditions, and film majority and minority constituents composition on performance, cost, and durability are complex. By incorporating combinatorial processing, research and development of the transition, and thermochromic materials and coatings in general, may be accelerated.
Embodiments described herein provide methods and systems for developing and evaluating thermochromic materials and thermochromic material processing conditions. In some embodiments, a plurality of regions (e.g., site-isolated regions) are designated on at least one substrate (e.g., a glass substrate). A first thermochromic material is formed on a first of the plurality of regions on the at least one substrate with a first set of processing conditions. A second thermochromic material is formed on a second of the plurality of regions on the at least one substrate with a second set of processing conditions. The second set of processing conditions is different than the first set of processing conditions. However, it should be understood, that in some embodiments, the use of the same set of processing conditions may be repeated on several of the regions (or one or more substrate) to test for consistency and repeatability.
The first thermochromic material and the second thermochromic material may then be characterized. One of the first set of processing conditions and the second set of processing conditions may be selected based on the characterizing of the first thermochromic material and the second thermochromic material.
As such, in accordance with some embodiments, combinatorial processing may be used to produce and evaluate different materials, substrates, chemicals, consumables, processes, coating stacks, and techniques related to thermochromic materials, barrier layers, nucleation layers, and adhesion layers, as well as build structures or determine how thermochromic materials coat, fill or interact with existing structures in order to vary materials, unit processes and/or process sequences across multiple site-isolated regions on the substrate(s). These variations may relate to specifications such as temperatures, exposure times, layer thicknesses, chemical compositions of majority and minority elements of layers, gas compositions, chemical compositions of wet and dry surface chemistries, power and pressure of sputter deposition conditions, humidity, etc. of the formulations and/or the substrates at various stages of the screening processes described herein. However, it should be noted that in some embodiments, the chemical composition (e.g., of the thermochromic material and/or of the other components) remains the same, while other parameters are varied, and in other embodiments, the chemical composition is varied.
Although not shown, an initial stage may be implemented which includes a fast screening/search of structure-material property relationships, known process-material relationships, known stack-product (device) relationships, etc. within any available literature prior to starting any experimentation that results in materials discovery. After this initial stage, for example, thousands of materials are evaluated during a materials discovery stage, 102. Materials discovery stage, 102, is also known as a primary screening stage performed using primary screening techniques. Primary screening techniques may include dividing substrates into coupons and depositing materials using varied processes. The materials are then evaluated, and promising candidates are advanced to the secondary screen, or materials and process development stage, 104. Evaluation of the materials is performed using metrology tools such as ellipsometers, XRF, stylus profilers, hall measurements, optical transmission, reflection, and absorption testers, electronic testers and imaging tools (i.e., microscopes).
The materials and process development stage, 104, may evaluate hundreds of materials (i.e., a magnitude smaller than the primary stage) and may focus on the processes used to deposit or develop those materials. Promising materials and processes are again selected, and advanced to the tertiary screen or process integration stage, 106, where tens of materials and/or processes and combinations are evaluated. The tertiary screen or process integration stage, 106, may focus on integrating the selected processes and materials with other processes and materials.
The most promising materials and processes from the tertiary screen are advanced to device qualification, 108. In device qualification, the materials and processes selected are evaluated for high volume manufacturing, which normally is conducted on full substrates within production tools, but need not be conducted in such a manner. The results are evaluated to determine the efficacy of the selected materials and processes. If successful, the use of the screened materials and processes can proceed to pilot manufacturing, 110.
The schematic diagram, 100, is an example of various techniques that may be used to evaluate and select materials and processes for the development of new materials and processes. The descriptions of primary, secondary, etc. screening and the various stages, 102-110, are arbitrary and the stages may overlap, occur out of sequence, be described and be performed in many other ways. Additionally, it should be understood that the complexity of the samples/materials, as well as the evaluation thereof, may increase at each stage (e.g., the second stage may be more complex than the first, etc.).
This application benefits from High Productivity Combinatorial (HPC) techniques described in U.S. patent application Ser. No. 11/674,137 filed on Feb. 12, 2007 which is hereby incorporated for reference in its entirety. Portions of the '137 application have been reproduced below to enhance the understanding of the present invention. The embodiments described herein enable the application of combinatorial techniques to process sequence integration in order to arrive at a globally optimal sequence of thermochromic devices, semiconductor devices, TFPV modules, optoelectronic devices, etc. manufacturing operations by considering interaction effects between the unit manufacturing operations, the process conditions used to effect such unit manufacturing operations, hardware details used during the processing, as well as materials characteristics of components utilized within the unit manufacturing operations. Rather than only considering a series of local optimums, i.e., where the best conditions and materials for each manufacturing unit operation is considered in isolation, the embodiments described below consider interactions effects introduced due to the multitude of processing operations that are performed and the order in which such multitude of processing operations are performed when fabricating thermochromic devices, semiconductor devices, TFPV modules, optoelectronic devices, etc. A global optimum sequence order is therefore derived and as part of this derivation, the unit processes, unit process parameters and materials used in the unit process operations of the optimum sequence order are also considered.
The embodiments described further analyze a portion or sub-set of the overall process sequence used to manufacture thermochromic devices, semiconductor devices, TFPV modules, optoelectronic devices, etc. Once the subset of the process sequence is identified for analysis, combinatorial process sequence integration testing is performed to optimize the materials, unit processes, hardware details, and process sequence used to build that portion of the device or structure. During the processing of some embodiments described herein, structures are formed on the processed substrate that are equivalent to the structures formed during actual production of the thermochromic devices, semiconductor devices, TFPV modules, optoelectronic devices, etc. For example, such structures may include, but would not be limited to, contact layers, buffer layers, absorber layers, or any other series of layers or unit processes that create an intermediate structure found on thermochromic devices, semiconductor devices, TFPV modules, optoelectronic devices, etc. While the combinatorial processing varies certain materials, unit processes, hardware details, or process sequences, the composition or thickness of the layers or structures or the action of the unit process, such as cleaning, surface preparation, deposition, surface treatment, etc. is substantially uniform through each discrete region. Furthermore, while different materials or unit processes may be used for corresponding layers or steps in the formation of a structure in different designated regions of the substrate during the combinatorial processing, the application of each layer or use of a given unit process is substantially consistent or uniform throughout the different regions in which it is intentionally applied. Thus, the processing is uniform within a region (inter-region uniformity) and between regions (intra-region uniformity), as desired. It should be noted that the process can be varied between regions, for example, where a thickness of a layer is varied or a material may be varied between the regions, etc., as desired by the design of the experiment.
The result is a series of regions on the substrate that contain structures or unit process sequences that have been uniformly applied within that region and, as applicable, across different regions. This process uniformity allows comparison of the properties within and across the different regions such that the variations in test results are due to the varied parameter (e.g., materials, unit processes, unit process parameters, hardware details, or process sequences) and not the lack of process uniformity. In the embodiments described herein, the positions of the discrete (or site-isolated) regions on the substrate can be defined as needed, but are preferably systematized for ease of tooling and design of experimentation. In addition, the number, variants and location of structures within each region are designed to enable valid statistical analysis of the test results within each region and across regions to be performed.
It should be appreciated that various other combinations of conventional and combinatorial processes can be included in the processing sequence with regard to
Under combinatorial processing operations the processing conditions at different regions can be controlled independently. Consequently, process material amounts, reactant species, processing temperatures, processing times, processing pressures, processing flow rates, processing powers, processing reagent compositions, the rates at which the reactions are quenched, deposition order of process materials, process sequence steps, hardware details, etc., can be varied from region to region on the substrate. Thus, for example, when exploring materials, a processing material delivered to a first and second region can be the same or different. If the processing material delivered to the first region is the same as the processing material delivered to the second region, this processing material can be offered to the first and second regions on the substrate at different concentrations. In addition, the material can be deposited under different processing parameters. Parameters which can be varied include, but are not limited to, process material amounts, reactant species, processing temperatures, processing times, processing pressures, processing flow rates, processing powers, processing reagent compositions, the rates at which the reactions are quenched, atmospheres in which the processes are conducted, an order in which materials are deposited, hardware details of the gas distribution assembly, etc. It should be appreciated that these process parameters are exemplary and not meant to be an exhaustive list as other process parameters commonly used in semiconductor device, TFPV module, optoelectronic device, etc. manufacturing may be varied.
Any type of chamber or combination of chambers may be implemented and the description herein is merely illustrative of one possible combination and not meant to limit the potential chamber or processes that can be supported to combine combinatorial processing or combinatorial plus conventional processing of a substrate or wafer. In some embodiments, a centralized controller, i.e., computing device 316, may control the processes of the HPC system, including the power supplies and synchronization of the duty cycles described in more detail below. Further details of one possible HPC system are described in U.S. application Ser. No. 11/672,478 filed Feb. 7, 2007, now U.S. Pat. No. 7,867,904 and claiming priority to U.S. Provisional Application No. 60/832,248 filed on Jul. 19, 2006, and U.S. application Ser. No. 11/672,473, filed Feb. 7, 2007, and claiming priority to U.S. Provisional Application No. 60/832,248 filed on Jul. 19, 2006, which are all herein incorporated by reference. With HPC system, a plurality of methods may be employed to deposit material upon a substrate employing combinatorial processes.
Substrate 406 may be a conventional round 200 mm, 300 mm, or any other larger or smaller substrate/wafer size. In some embodiments, substrate 406 may be a square, rectangular, or other shaped substrate. In some embodiments, substrate 406 is made of glass. However, in other embodiments, the substrate 406 is made of a semiconductor material, such as silicon. One skilled in the art will appreciate that substrate 406 may be a blanket substrate, a coupon (e.g., partial wafer), or even a patterned substrate having predefined regions. In some embodiments, substrate 406 may have regions defined through the processing described herein. The term region is used herein to refer to a localized (or site-isolated) area on a substrate which is, was, or is intended to be used for processing or formation of a selected material. The region can include one region and/or a series of regular or periodic regions predefined on the substrate. The region may have any convenient shape, e.g., circular, rectangular, elliptical, wedge-shaped, etc. In the semiconductor field, a region may be, for example, a test structure, single die, multiple dies, portion of a die, other defined portion of substrate, or an undefined area of a substrate, e.g., blanket substrate which is defined through the processing.
Top chamber portion 418 of chamber, 400, in
The base of process kit shield 412 includes an aperture 414 through which a surface of substrate 406 is exposed for deposition or some other suitable semiconductor processing operations. Aperture shutter 420 which is moveably disposed over the base of process kit shield 412. Aperture shutter 420 may slide across a bottom surface of the base of process kit shield 412 in order to cover or expose aperture, 414, in some embodiments. In other embodiments, aperture shutter 420 is controlled through an arm extension which moves the aperture shutter to expose or cover aperture 414. It should be noted that although a single aperture is illustrated, multiple apertures may be included. Each aperture may be associated with a dedicated aperture shutter or an aperture shutter can be configured to cover more than one aperture simultaneously or separately. Alternatively, aperture 414 may be a larger opening and aperture shutter 420 may extend with that opening to either completely cover the aperture or place one or more fixed apertures within that opening for processing the defined regions. The dual rotary substrate support 404 is central to the site-isolated mechanism, and allows any location of the substrate or wafer to be placed under the aperture 414. Hence, the site-isolated deposition is possible at any location on the wafer/substrate.
In the example shown in
Top chamber portion 418 of chamber 400 of
Power source 424 provides power for sputter guns 416 whereas power source 426 provides RF bias power to an electrostatic chuck. As mentioned above, the output of power source 426 is synchronized with the output of power source 424. It should be appreciated that power source 424 may output a direct current (DC) power supply or a radio frequency (RF) power supply. In other embodiments, the DC power is pulsed and the duty cycle is less than 30% on-time at maximum power in order to achieve a peak power of 10-15 kilowatts. Thus, the peak power for high metal ionization and high density plasma is achieved at a relatively low average power which will not cause any target overheating/cracking issues. It should be appreciated that the duty cycle and peak power levels are exemplary and not meant to be limiting as other ranges are possible and may be dependent on the material and/or process being performed.
Using processing chamber 400, perhaps in combination with other processing tools, thermochromic materials may be developed and evaluated in the manner described above. In particular, in some embodiments, thermochromic materials may be formed on different site-isolated regions of substrate 406 (or on multiple substrates) under varying processing conditions (including the formation/deposition of different thermochromic material). For example, thermochromic material may be ejected from one of more of targets 504 and deposited onto a first of the regions on substrate 406 under a first set of processing conditions, and either sequentially or simultaneously, thermochromic material may be ejected from one of more of targets 504 and deposited onto a second of the regions on substrate 406 under a different, second set of processing conditions. The thermochromic material(s) (and/or thermochromic material processing conditions) may then be characterized. Particular materials and/or processing conditions may then be selected (e.g., for further testing or use in devices) based on the desired parameters.
It should be understood that the development of the thermochromic materials may involve the use of multiple processing tools, such as modules 304-312 in
The combinatorial wet processing tool 600 includes a housing (and/or processing chamber) 602, a well holder 604 holding wells 606, and a dispense arm 608 having a dispense head 610. The wet processing tool 600 also includes a reactor assembly 612 having an array or reactors (or fluid containers) 614 positioned over a substrate support 616. A substrate 618 is placed on the substrate support 616 and positioned relative to the reactors 614 such that bottom edges of the reactors contact the substrate 618 and form seals around respective, site-isolated portions of the substrate 618. The dispense arm 610 may retrieve (e.g., via syringes) formulations (e.g., thermochromic materials) from the wells 606 and dispense them into the reactors 614. Because of the seals formed between the reactors 614 and the substrate 618, the formulations remain within the reactors 614 and on the respective regions of the substrate 618, and are thus isolated from the other formulations and regions on the substrate 618. The formulations may be varied by varying, for example, the chemical composition or exposure time.
In the example shown, the thermochromic coating 704 includes a first barrier layer 710, a thermochromic layer 712, and a second barrier layer 714. Such a thermochromic coating 704 may be formed by, for example, first performing a wet cleaning on the surface of the substrate 702 and sequentially forming the first barrier layer 710, the thermochromic material 712, and the second barrier layer 714 using, for example, sputter deposition. The first barrier layer may be made of, for example, silicon oxide. The second barrier layer may be made of, for example, silicon nitride. After the second barrier layer 714 is formed, the device 700 may undergo an annealing process performed in an environment of, for example, nitrogen, argon, or air. Additionally, although not shown, in some embodiments, a nucleation layer may be formed on the first barrier layer 710, and an adhesion layer may be included between the thermochromic material 712 and the second barrier layer 714. However, in other embodiments, even fewer layers may be used.
Furthermore, it should be understood that the thermochromic device 700 may be a portion of a larger, more complex device or system, such as a thermochromic window. Such a thermochromic window may include multiple glass substrates (or panes) and other coatings (or layers). For example, a low emissivity (“low-e”) coating (e.g., utilizing a silver layer) may be formed on another pane of the window, and various barrier or spacer layers may be formed between adjacent panes.
After being installed and in use, when the temperature of thermochromic coating 704 is below the transition temperature of the particular thermochromic material used, electromagnetic radiation (e.g., solar radiation) passes from second side 708 to first side 706 through both thermochromic coating 704 and substrate 706. However, when the temperature of the thermochromic coating 704 reaches the transition temperature of the particular thermochromic material, the material undergoes a semiconductor-to-metal transition causing the color, reflectance, and transmittance of thermochromic coating 704, and thus the entire device 700, to change. After the transition, only a reduced amount of electromagnetic radiation passes from second side 708 to first side 706 of device 700, while the remainder is reflected. When particular thermochromic materials are used, when the temperature of the thermochromic coating drops below the transition temperature, the transition will be reversed such that the original amount solar radiation will pass through device 700.
Thus, in some embodiments, methods for evaluating thermochromic material processing conditions are provided, the methods comprising. A plurality of site-isolated regions on at least one substrate are designated. A first thermochromic material is formed on a first of the plurality of regions on the at least one substrate with a first set of processing conditions. A second thermochromic material is formed on a second of the plurality of regions on the at least one substrate with a second set of processing conditions. The second set of processing conditions is different than the first set of processing conditions.
In some embodiments, methods for evaluating thermochromic material processing conditions are provided, the methods comprising. A substrate, having a plurality of site-isolated regions thereon, is positioned in a processing chamber. A first thermochromic material is formed on a first of the plurality of regions on the substrate with a first set of processing conditions. A second thermochromic material is formed on a second of the plurality of regions on the substrate with a second set of processing conditions. The second set of processing conditions is different than the first set of processing conditions.
In some embodiments, methods for evaluating thermochromic material processing conditions are provided. A substrate, having a plurality of site-isolated regions thereon, is positioned in a processing chamber having at least one target comprising a thermoelectric material positioned therein. The thermoelectric material is caused to be ejected from the at least one target under a first set of processing conditions such that the thermoelectric material is deposited on a first of the plurality of regions on the substrate. The thermoelectric material is caused to be ejected from the at least one target under a second set of processing conditions such that the thermoelectric material is deposited on a second of the plurality of regions on the substrate. The second set of processing conditions is different than the first set of processing conditions
Although the foregoing examples have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention. The disclosed examples are illustrative and not restrictive.
