Patent Application
20140273497
The present invention relates to systems and method for processing substrates. More particularly, this invention relates to wet processing systems and methods for semiconductor devices in a manner such that the processing formulations are replenished.
Combinatorial processing enables rapid evaluation of semiconductor, solar, or energy processing operations. The systems supporting the combinatorial processing are flexible and 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), doping, etc. Similar processing techniques apply to the manufacture of integrated circuit (IC) semiconductor devices, thin-film photovoltaic (TFPV) devices, flat panel displays, optoelectronics devices, data storage devices, magneto electronic devices, magneto optic devices, packaged devices, and the like. As feature sizes continue to shrink, improvements, whether in materials, unit processes, or process sequences, are continually being sought for the deposition processes. However, semiconductor and solar companies conduct research and development (R&D) on full wafer 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 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.
However, current equipment used for combinatorial wet processing may not accurately simulate the processing conditions used in high volume manufacturing (HVM), as the formulations used may be lost during processing (e.g., due to evaporation), the formulations may become diluted during the reaction cycles, etc.
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.
The term “horizontal” as used herein will be understood to be defined as a plane parallel to the plane or surface of the substrate, regardless of the orientation of the substrate. The term “vertical” will refer to a direction perpendicular to the horizontal as previously defined. Terms such as “above”, “below”, “bottom”, “top”, “side” (e.g. sidewall), “higher”, “lower”, “upper”, “over”, and “under”, are defined with respect to the horizontal plane. The term “on” means there is direct contact between the elements. The term “above” will allow for intervening elements.
The manufacture of various devices, such as, thin-film photovoltaic (TFPV) modules, semiconductor devices, thermochromic devices, optoelectronic devices, etc., entails the integration and sequencing of many unit processing steps. For example, device manufacturing typically includes a series of processing steps such as cleaning, surface preparation, deposition, patterning, etching, thermal annealing, and other related unit processing steps. The precise sequencing and integration of the unit processing steps enables the formation of functional devices meeting desired performance metrics such as efficiency, power production, and reliability.
As part of the discovery, optimization and qualification of each unit process, it is desirable to be able to i) test different materials, ii) test different processing conditions within each unit process module, iii) test different sequencing and integration of processing modules within an integrated processing tool, iv) test different sequencing of processing tools in executing different process sequence integration flows, and combinations thereof in the manufacture of devices such as integrated circuits. In particular, there is a need to be able to test i) more than one material, ii) more than one processing condition, iii) more than one sequence of processing conditions, iv) more than one process sequence integration flow, and combinations thereof, collectively known as “combinatorial process sequence integration,” on a single monolithic substrate (e.g., an integrated or short-looped wafer) without the need of consuming the equivalent number of monolithic substrates per material(s), processing condition(s), sequence(s) of processing conditions, sequence(s) of processes, and combinations thereof. This can greatly improve both the speed and reduce the costs associated with the discovery, implementation, optimization, and qualification of material(s), process(es), and process integration sequence(s) required for manufacturing.
Systems and methods for High Productivity Combinatorial (HPC) processing are described in U.S. Pat. No. 7,544,574, filed on Feb. 10, 2006, U.S. Pat. No. 7,824,935, filed on Jul. 2, 2008, U.S. Pat. No. 7,871,928, filed on May 4, 2009, U.S. Pat. No. 7,902,063, filed on Feb. 10, 2006, and U.S. Pat. No. 7,947,531, filed on Aug. 28, 2009, which are all herein incorporated by reference. Systems and methods for HPC processing are further described in U.S. patent application Ser. No. 11/352,077, filed on Feb. 10, 2006, claiming priority from Oct. 15, 2005, U.S. patent application Ser. No. 11/419,174, filed on May 18, 2006, claiming priority from Oct. 15, 2005, U.S. patent application Ser. No. 11/674,132, filed on Feb. 12, 2007, claiming priority from Oct. 15, 2005, and U.S. patent application Ser. No. 11/674,137, filed on Feb. 12, 2007, claiming priority from Oct. 15, 2005 which are all herein incorporated by reference.
HPC processing techniques have been successfully adapted to wet chemical processing such as etching and cleaning. HPC processing techniques have also been successfully adapted to deposition processes such as physical vapor deposition (PVD), atomic layer deposition (ALD), and chemical vapor deposition (CVD).
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 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.
This application benefits from High Productivity Combinatorial (HPC) techniques described in U.S. patent application Ser. No. 11/674,137m 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, for example, device 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 a device. 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 a device. 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 device. 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 devices. 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 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 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 device manufacturing may be varied.
Some embodiments described herein provide systems and methods for performing wet processing on substrates, such as semiconductor substrates, in a combinatorial manner. That is, the systems and methods allow for varying processing conditions across multiple site-isolated regions on the substrate(s). Additionally, the systems and methods provide a way to more closely match processing conditions in a manufacturing environment. This is accomplished by replenishing (and/or “spiking”) the wet processing formulations while the wet process(es) are being performed, as is often performed during high volume manufacturing (HVM). During HVM, this is often desirable to, for example, maintain temperatures driven by exothermic reactions, maintaining etch or removal rates, and/or replace solvents that are lost during processing (e.g., via evaporation).
In some embodiments, the combinatorial aspect of the processing may be related to varying processing conditions independent of any replenishing (and/or spiking) of the wet processing formulations. That is, the replenishing may be carried out in a non-combinatorial manner on a set of reactions (or site-isolated regions) which are otherwise being performed combinatorially. In some embodiments, the combinatorial aspect of the processing may be related to the replenishing. That is, the processing conditions of the replenishing may be combinatorially varied across the set of reactions, while the reactions are otherwise performed in a non-combinatorial manner. While in some embodiments, both the reactions themselves and the replenishing of the formulations are performed in a combinatorial manner.
The wet processing tool 302 includes a housing 308 enclosing a processing chamber 310, a substrate support 312, and a wet processing assembly 314. Referring now to
The substrate 316 may be a conventional, round substrate (or wafer) having a diameter of, for example, 200 millimeter (mm), 300 mm, or 450 mm. In some embodiments, the substrate 316 is, for example, an integrated or short-looped patterned wafer. In other embodiments, the substrate 316 may have other shapes, such as a square or rectangular. It should be understood that the substrate 316 may be a blanket substrate (i.e., having a substantial uniform surface), a coupon (e.g., partial wafer), or even a patterned substrate having site-isolated regions (or locations) 320. The term region is used herein to refer to a localized area on a substrate which is, was, or is intended to be used for processing or formation of a selected material. The region may include one region and/or a series of regular or periodic regions pre-formed 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 die, portion of a die, other defined portion of substrate, or a undefined area of a, e.g., blanket substrate which is defined through the processing.
Still referring to
The wet processing units 324 are arranged in a series of rows (or sticks) 332, with each of the rows 332 being positioned between adjacent scaffolding bars 326.
Referring again to
The processing fluid supply system 304 includes one or more supplies of various processing fluids, as well as temperature control units to regulate the temperatures of the various fluids. In some embodiments, the processing fluids held by the processing fluid supply system 304 include wet processing formulations and/or wet processing formulation components. “Wet processing formulations” may refer to “complete” formulations which may be used to perform particular wet processes on the substrate 326. “Wet processing formulation components” may refer to liquids which may be combined to form wet processing formulations, or alternatively, the complete wet processing formulations. As such, in some embodiments, the wet processing formulations may include one or more wet processing formulation component (i.e., each of the wet processing formulation components may be an “ingredient” for a wet processing formulation). However, it should be noted that in some embodiments, the wet processing formulation components may be fluids which are not components of (at least some of) the complete wet processing formulations already present in the processing fluid supply system 304 (e.g., the wet processing formulation components are “new” ingredients for the wet processing formulations).
The control system (or controller) 306 includes, for example, a processor and memory (i.e., a computing system) in operable communication with the processing fluid supply system 304 and the wet processing units 324 and is configured to control the operation thereof as described below.
Referring again to
The liquid container body 344 includes a main portion 348 and an overflow portion 350. The main portion 348 of the liquid container body 344 houses the transducer 338 and encloses a reactor region 352 which is in contact with the substrate 316. The overflow portions 350 enclose an overflow region 354 which surrounds the reactor region 352 and is not in contact with the substrate 316. The liquid container body 344 further includes an inlet port 356 in fluid communication with the reactor region 352 and the processing fluid supply system 304 (via fluid lines 340), and outlet ports 358 and 360 in fluid communication with the reactor region 352 and the overflow region 354, respectively, as well as the processing fluid supply system 304 (via fluid lines 340). As shown, the transducer 338 is suspended a distance 362 above the substrate 316. As described below, in one embodiment, the distance 362 may be varied (e.g., between 1 mm and 50 mm), which effects the potency of the cleaning effect (i.e., a second order effect).
The sealing member 346 is positioned between the main portion 348 of the liquid container body 344 and the substrate 316. The sealing member 316 may take the form of an o-ring or lip seal and may be made of a compressible material, such as rubber, such that when a force (i.e., the weight of the wet processing assembly 314) is applied onto it towards the substrate 316, a seal is formed between the liquid container body 344 and the substrate 316.
Referring now to
The system 300 may then simultaneously perform any of numerous wet processing methods on the regions 320 of the substrate 316. Examples of wet processes include wet cleanings, wet etches and/or strips, and electroless depositions. Referring to
In some embodiments, after the wet processing formulations have been dispensed into the wet processing units 324, additional wet processing formulation(s) and/or wet processing formulation components are dispensed into the wet processing units 324 to “replenish” and/or “spike” (and/or add new components/ingredients to) the wet processing formulations. As will be appreciated by one skilled in the art, replenishing and/or spiking the wet processing formulations may allow the reactions to occur in a manner which more accurately simulates high volume manufacturing (HVM) processing.
For example, in some embodiments, the fluid supply system 304 provides additional wet processing formulation(s) to at least some of the wet processing units 324 to replace formulation that has been lost due to, for example, evaporation. In some embodiments, the fluid supply system 304 provides particular wet processing formulation components to at least some of the wet processing units 324 to spike the chemistry of the processes taking place. For example, during an etching or wet cleaning process, particular components of the wet processing formulations may be diluted such that the effectiveness of the reaction is reduced. In such cases, the fluid supply system 304 may dispense an additional amount of those particular wet processing formulation components into the wet processing units 334 to maintain the effectiveness of the reactions. In some embodiments, the additional wet processing formulation(s) (and/or wet processing formulation components) added to the reactions are of a chemical composition that is different than the wet processing formulation already dispensed (e.g., the wet processing formulation component used to spike the reaction is not a component of the wet processing formulation performing the reaction).
In some embodiments, the additional processing fluids (wet processing formulation and/or wet processing formulation components) are only added a predetermined time after the initial volume(s) wet processing formulation(s) have been dispensed into the wet processing units 324 to begin the reactions. For example, when the system 300 is performing etching processes which will be spiked, the additional wet processing formulation component(s) may not be added until, for example, 5 minutes after the reactions have been initiated (i.e., 5 minutes after the cessation of the dispensing of the initial wet processing formulations into the wet processing units 324). The spiking (and/or replenishing) may be performed multiple times during a single reaction cycle.
In some embodiments, the wet processing system 300 (e.g., particularly the processing fluid supply system 304 and/or the control system 306) is configured to intentionally vary (or create differences between) the processing conditions for the wet processes performed on two or more of the regions 320. In some embodiments, the varying of the processing conditions is associated with (or related to) the processing conditions in a manner that is independent of any replenishing or spiking of the wet processing formulations (i.e., the reactions are performed in a combinatorial manner before or regardless of any replenishing/spiking). In some embodiments, the varying is associated with the replenishing/spiking independent of the reactions in progress (i.e., the reactions are initially performed in a non-combinatorial manner until the replenishing/spiking). However, in some embodiments, the reactions are performed in a combinatorial manner independent of the replenishing/spiking, and the replenishing/spiking is then also performed in a combinatorial manner.
Exemplary variations generated between two or more of the reactions include varying the chemical compositions, pH levels, temperatures of the processing fluids (including any processing gases), reaction times (e.g., the duration of the reactions and/or the timing of the replenishing/spiking), processing fluid volumes (e.g., of the initial wet processing formulations and/or the of the wet processing formulation components added during replenishing/spiking) parameters related to the operation of the transducers 338 (i.e., in embodiments which include the transducers 338), and/or any combination thereof. Again, it should be noted that the variations described above may be associated with the complete wet processing formulations and/or the wet processing formulation components added to the wet processing formulations. As described above, such variation(s) may be introduced at the initiation of a reaction cycle and/or when the wet processing formulations are replenishing and/or spiked.
One possible type of wet processing formulation that may be used is cleaning liquids. An example of a cleaning formulation is a mixture of three wet processing formulation components, such as ammonium hydroxide (NH4OH), hydrogen peroxide (H2O2), and deionized (DI) water (H2O). A typical concentration ratio for the mix is 1:1:5 NH4OH:H2O2:H2O. However, as described above, in some embodiments, this ratio may be varied among the different liquid containers 334 at the initiation of the reaction cycles, while in some embodiments this ratio may be varied by spiking the reactions with different amounts of one of the components, such as ammonium hydroxide, after the reactions have been initiated.
Another example of a cleaning formulation is a mixture of hydrochloric acid (HCl), hydrogen peroxide (H2O2), and deionized (DI) water (H2O). A typical concentration ratio for the mix is 1:1:5 HCl:H2O2:H2O. Again, however, this ratio may be varied among the different liquid containers 334 at the initiation of the reaction cycle and/or during the replenishing/spiking of the reactions.
It should be understood that the size, shape, and number of the liquid containers 334 and/or the corresponding regions 320 on the substrate 316 may be different in other embodiments. For example, in some embodiments, the substrate 316 may include four regions 320, each of which essentially occupies a quadrant on the substrate 316. In some embodiments, the regions 320 may be in the shape of parallel strips extending across the substrate 316. It should be understood that in such embodiments, the liquid containers 334 may be sized and shaped in such a way to as to seal these different sizes/shapes of regions 320.
The combinatorial wet processing tool 900 includes a housing (and/or processing chamber) 902, a well holder 904 holding wells 906, and a dispense arm 908 having a dispense head 910. The wet processing tool 900 also includes a reactor assembly 912 having an array or reactors (or fluid containers) 914 positioned over a substrate support 916. A substrate 918 is placed on the substrate support 916 and positioned relative to the reactors 914 such that bottom edges of the reactors 914 contact the substrate 918 and form seals around respective, site-isolated portions of the substrate 918. The dispense arm 910 may retrieve (e.g., via syringes) formulations (e.g., thermochromic materials) from the wells 906 and dispense them into the reactors 914. Because of the seals formed between the reactors 914 and the substrate 918, the formulations remain within the reactors 914 and on the respective regions of the substrate 918, and are thus isolated from the other formulations and regions on the substrate 918.
Although not shown in
At block 1004, wet processes are simultaneously performed on each of the site-isolated regions on the substrate. As described above, the wet processes may be performed by exposing each of the site-isolated regions to a wet processing formulation.
At block 1006, a wet processing formulation component is added to at least some of the wet processes. As described above, the wet processing formulations may, for example, have the same chemical composition as the wet processing formulation to which they are added, or may be one of the components of the wet processing formulations.
At block 1008, a processing condition is varied between at least two of the wet processes. As described above, the variation may be associated with the processing conditions of the wet processes before the wet processing formulation components are added and/or may be associated with the addition of the wet processing formulation components. At block 1010, the method 1000 ends.
Thus, in some embodiments, a method for processing a substrate is provided. A substrate having a plurality of site-isolated regions defined thereon is provided. A plurality of wet processes is simultaneously performed. Each of the plurality of wet processes is performed on one of the plurality of site-isolated regions defined on the substrate. The simultaneously performing includes exposing each of the plurality of site-isolated regions to one of a plurality of wet processing formulations. Each of the plurality of wet processing formulations includes a component. The respective component is added to at least some of the plurality of wet processing formulations during the exposing. A processing condition is varied between at least two of the plurality of wet processes in a combinatorial manner.
In some embodiments, a method for processing a substrate is provided. A substrate having a plurality of site-isolated regions defined thereon is provided. A plurality of wet processes are simultaneously performed. Each of the plurality of wet processes is performed on one of the plurality of site-isolated regions defined on the substrate. The simultaneously performing includes exposing each of the plurality of site-isolated regions to a one of a plurality of wet processing formulations by dispensing each of the plurality of wet processing formulations onto the respective site-isolated region. Each of the plurality of the wet processing formulations includes a component. The respective component is added to at least some of the plurality of wet processing formulations during the exposing and after the cessation of the dispensing of the plurality of wet processing formulations. At least one processing condition is varied between at least two of the plurality of wet processes in a combinatorial manner.
In some embodiments, a wet processing tool is provided. The wet processing tool includes a housing defining a processing chamber. A substrate support is coupled to the housing and configured to support a substrate within the processing chamber. A plurality of reactors are coupled to the housing. Each of the plurality of reactors is positioned to define one of a plurality of site-isolated regions on the substrate and configured to hold a liquid on the respective one of the plurality of site-isolated regions. A fluid supply system is coupled to the plurality of reactors and configured to dispense each of a plurality of wet processing formulations including a component into one of the plurality of reactors and dispense the respective components into at least some of the plurality of reactors. A control system is coupled to the fluid supply system. The control system is configured to dispense each of the plurality wet processing formulations into the respective reactor to simultaneously perform a plurality of wet processes. Each of the plurality of wet processes is performed on one of the plurality of site-isolated regions defined on the substrate. The respective component is added to at least some of the plurality of wet processing formulations during the simultaneously performing of the plurality of wet processes. A processing condition is varied between at least two of the plurality of wet processes in a combinatorial manner.
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.
This application claims priority to U.S. Provisional Patent Application No. 61/780,128, filed Mar. 13, 2013, entitled “HPC Methods for Processing Materials,” which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61780128 | Mar 2013 | US |
