Patent Application
20140349469
This disclosure relates to equipment and methods for forming electromechanical systems.
Electromechanical systems (EMS) include devices having electrical and mechanical elements, actuators, transducers, sensors, optical components (such as mirrors and optical film layers) and electronics. Electromechanical systems can be manufactured at a variety of scales including, but not limited to, microscales and nanoscales. For example, microelectromechanical systems (MEMS) devices can include structures having sizes ranging from about a micron to hundreds of microns or more. Nanoelectromechanical systems (NEMS) devices can include structures having sizes smaller than a micron including, for example, sizes smaller than several hundred nanometers. Electromechanical elements may be created using deposition, etching, lithography, and/or other micromachining processes that etch away parts of substrates and/or deposited material layers, or that add layers to form electrical and electromechanical devices.
One type of electromechanical systems device is called an interferometric modulator (IMOD). As used herein, the term interferometric modulator or interferometric light modulator refers to a device that selectively absorbs and/or reflects light using the principles of optical interference. In some implementations, an interferometric modulator may include a pair of conductive plates, one or both of which may be transparent and/or reflective, wholly or in part, and capable of relative motion upon application of an appropriate electrical signal. In an implementation, one plate may include a stationary layer deposited on a substrate and the other plate may include a reflective membrane separated from the stationary layer by an air gap. The position of one plate in relation to another can change the optical interference of light incident on the interferometric modulator. Interferometric modulator devices have a wide range of applications, and are anticipated to be used in improving existing products and creating new products, especially those with display capabilities.
Typically one of the last fabrication processes before packaging an electromechanical system apparatus is the removal of a sacrificial layer from underneath a movable layer to define the cavity through which the movable layer can move. The removal of the sacrificial layer is often referred to as a release etch. After release, the device is vulnerable and sensitive to damage during subsequent handling and processing.
The systems, methods and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.
One innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for processing substrates. The apparatus includes a process chamber configured to process multiple substrates. The process chamber includes a plurality of stacked individual subchambers. Each subchamber is configured to process one substrate. The apparatus includes a common reactant source configured to selectively provide a reactant to each of the subchambers in parallel. The apparatus includes a common exhaust pump selectively connected to each of the subchambers.
In some implementations, a cluster tool including two or more of the apparatus is provided. The cluster tool includes at least two of: a first processing chamber including a first plurality of subchambers in fluid communication with a common etchant source including a fluorine based etchant; a second processing chamber including a second plurality of subchambers in fluid communication with a common source of atomic layer deposition reactants, including a first common oxidizing source and a second common source including one of a semiconductor and a metal source; and a third processing chamber including a third plurality of subchambers in fluid communication with a common source of reactant to form a self-assembled monolayer (SAM).
One innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for processing electromechanical systems devices. The apparatus includes a process chamber configured to process multiple substrates, including a means for isolating the process chamber into a plurality of stacked individual subchambers. Each subchamber is configured to process one substrate. The apparatus includes a means for selectively providing a common reactant to each of the subchambers. The apparatus includes a common means for selectively exhausting each of the subchambers.
In some implementations, a cluster tool including two or more of the apparatus is provided. The cluster tool includes two or more of: a first processing chamber including a first plurality of subchambers, including means for removing sacrificial layers from the substrates; a second processing chamber including a second plurality of subchambers, including means for forming an ALD layer on the substrates; and a third processing chamber including a third plurality of subchambers, including means for forming a self-assembled monolayer (SAM) on the substrates.
One innovative aspect of the subject matter described in this disclosure can be implemented in a method of processing substrates. The method includes transferring multiple substrates into a process chamber, wherein the process chamber includes a plurality of stacked individual subchambers, each subchamber configured to process one substrate. The method includes exposing the substrates to a reactant provided from a reactant source commonly connected to each of the subchambers. The method includes exhausting the reactant from the subchambers through an exhaust commonly and selectively connected to each of the subchambers.
In some implementations, the method is performed in two or more process chambers. In such a method, exposing the substrates to the reactant includes two or more of: exposing the substrates to a vapor phase etchant; exposing the substrates to vapor phase reactants to form a thin film on the substrates by ALD, and exposing the substrates to vapor phase reactants to form a self-assembled monolayer (SAM) on the substrates.
One innovative aspect of the subject matter described in this disclosure can be implemented in a method of processing substrates. The method includes transferring multiple substrates into a process chamber, wherein the process chamber includes a plurality of stacked individual subchambers, each subchamber configured to process one substrate. The method includes closing an outlet valve connected upstream of a first subchamber and downstream of a buffer. The method includes opening an inlet valve positioned upstream of the buffer. The method includes flowing reactant from a reactant source through the inlet valve and into the buffer. The method includes closing the inlet valve after pressure within the buffer reaches a pressure threshold. The method includes opening the outlet valve while the inlet valve is closed, to flow a pressure-controlled dose of reactant from the buffer into the first subchamber.
Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.
Like reference numbers and designations in the various drawings indicate like elements.
The following description is directed to certain implementations for the purposes of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations may be implemented in any device or system that can be configured to display an image, whether in motion (such as a video) or stationary (such as a still image), and whether textual, graphical or pictorial. More particularly, it is contemplated that the described implementations may be included in or associated with a variety of electronic devices such as, but not limited to: mobile telephones, multimedia Internet enabled cellular telephones, mobile television receivers, wireless devices, smartphones, Bluetooth® devices, personal data assistants (PDAs), wireless electronic mail receivers, hand-held or portable computers, netbooks, notebooks, smartbooks, tablets, printers, copiers, scanners, facsimile devices, GPS receivers/navigators, cameras, MP3 players, camcorders, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, electronic reading devices (i.e., e-readers), computer monitors, auto displays (including odometer and speedometer displays, etc.), cockpit controls and/or displays, camera view displays (such as the display of a rear view camera in a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, microwaves, refrigerators, stereo systems, cassette recorders or players, DVD players, CD players, VCRs, radios, portable memory chips, washers, dryers, washer/dryers, parking meters, packaging (such as in electromechanical systems (EMS), microelectromechanical systems (MEMS) and non-MEMS applications), aesthetic structures (such as display of images on a piece of jewelry) and a variety of EMS devices. The teachings herein also can be used in non-display applications such as, but not limited to, electronic switching devices, radio frequency filters, sensors, accelerometers, gyroscopes, motion-sensing devices, magnetometers, inertial components for consumer electronics, parts of consumer electronics products, varactors, liquid crystal devices, electrophoretic devices, drive schemes, manufacturing processes and electronic test equipment. Thus, the teachings are not intended to be limited to the implementations depicted solely in the Figures, but instead have wide applicability as will be readily apparent to one having ordinary skill in the art.
Processing electromechanical systems devices can include a release etch process to etch a portion of each device to form an internal cavity in the device. After release, an antistiction layer can be formed in the cavity to reduce stiction in the device. The antistiction layer can include a layer formed by atomic layer deposition (ALD). In some implementations, additional deposition of a self-assembled monolayer (SAM) formed on top of the ALD layer can provide even further anti-stiction properties over an ALD layer alone. In some implementations, the SAM layer can also be formed over an already-existing layer (such as an etch stop layer) in the device, in which case a SAM anti-stiction layer may be formed after release without an ALD process being used. Each of the release etch, deposition of the ALD layer, and deposition of the SAM can be implemented within a standalone process tool, or integrated into a cluster tool. “Batch process chamber” or “batch tool” as used herein, refers to a tool configured for processing multiple substrates. As will be appreciated from the implementations described herein, a batch process chamber can employ a single chamber; a single outer chamber with a single inner chamber, in which substrates are in open communication with one another and a common gas sources and exhaust; or a single outer chamber and multiple inner chambers with individual gas feeds for the inner chambers. Multiple batch process chambers of one or more of the above configurations can be integrated into a cluster tool with one or more common transfer chambers through which substrates can access the process chambers. “Batch processing” refers to a process in which multiple substrates are simultaneously processed in parallel with a process chamber.
Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. The use of batch reactors to process multiple substrates can lower the production costs by increasing the throughput of substrates (that is, substrates processed per hour) and limit exposure to contaminants for sensitive post-release devices. Furthermore, precautions such as controlled relative pressures among a transfer chamber and attached separate processing chambers can decrease the risk for contamination of the substrate between processes and cross contamination of the different processing gases used for the etch/release, ALD layer formation, and SAM formation. In some implementations the transfer chamber and attached separate processing chambers can reduce risk for contamination of the substrate by using a low vacuum pressure in the transfer chamber and in the process chambers after processing and prior to, and during, substrate transfer. In some implementations, the multiple substrates can be commonly processed in a “batch” in each separate processing chamber.
In some implementations, the multiple substrates can be processed in a plurality of processing subchambers within each separate processing chamber. A processing chamber with such subchambers can be part of a cluster tool, or part of a standalone process tool. Such a process tool can be configured for one or more of etch/release, ALD layer formation and SAM formation, or can be configured for other types of processing. Each processing subchamber can be configured to process a subset of the multiple substrates. In some implementations, each processing subchamber can be configured to process a single substrate. Lower impurities in the device cavity can result in improved electrical properties and device performance and stability. In some implementations, a common reactant source can be configured to provide a reactant to each of the subchambers in parallel, and a common exhaust pump can be connected to each of the subchambers. In some implementations, a manifold can provide flowpaths from the common source of reactant to each subchamber that are approximately equal. In some implementations, an accumulator can be positioned between the common reactant source and upstream of the subchambers. In some implementations, a pressure-controlled dose of reactant can be provided into each subchamber.
It can be challenging to achieve both uniformity of processing and efficiency for treatment of large format substrates, such as glass or plastic substrates employed in the flat panel display industry. By providing multiple subchambers fed in parallel, uniformity advantages of single substrate processing can be combined with the efficiencies of batch processing.
An example of a suitable EMS or MEMS device, to which the described implementations may apply, is a reflective display device. Reflective display devices can incorporate interferometric modulators (IMODs) to selectively absorb and/or reflect light incident thereon using principles of optical interference. IMODs can include an absorber, a reflector that is movable with respect to the absorber, and an optical resonant cavity defined between the absorber and the reflector. The reflector can be moved to two or more different positions, which can change the size of the optical resonant cavity and thereby affect the reflectance of the interferometric modulator. The reflectance spectrums of IMODs can create fairly broad spectral bands which can be shifted across the visible wavelengths to generate different colors. The position of the spectral band can be adjusted by changing the thickness of the optical resonant cavity. One way of changing the optical resonant cavity is by changing the position of the reflector.
The IMOD display device can include a row/column array of IMODs. Each IMOD can include a pair of reflective layers, i.e., a movable reflective layer and a fixed partially reflective layer, positioned at a variable and controllable distance from each other to form an air gap (also referred to as an optical gap or cavity). The movable reflective layer may be moved between at least two positions. In a first position, i.e., a relaxed position, the movable reflective layer can be positioned at a relatively large distance from the fixed partially reflective layer. In a second position, i.e., an actuated position, the movable reflective layer can be positioned more closely to the partially reflective layer. Incident light that reflects from the two layers can interfere constructively or destructively depending on the position of the movable reflective layer, producing either an overall reflective or non-reflective state for each pixel. In some implementations, the IMOD may be in a reflective state when unactuated, reflecting light within the visible spectrum, and may be in a dark state when unactuated, absorbing and/or destructively interfering light within the visible range. In some other implementations, however, an IMOD may be in a dark state when unactuated, and in a reflective state when actuated. In some implementations, the introduction of an applied voltage can drive the pixels to change states. In some other implementations, an applied charge can drive the pixels to change states.
The depicted portion of the pixel array in
In
The optical stack 16 can include a single layer or several layers. The layer(s) can include one or more of an electrode layer, a partially reflective and partially transmissive layer and a transparent dielectric layer. In some implementations, the optical stack 16 is electrically conductive, partially transparent and partially reflective, and may be fabricated, for example, by depositing one or more of the above layers onto a transparent substrate 20. The electrode layer can be formed from a variety of materials, such as various metals, for example indium tin oxide (ITO). The partially reflective layer can be formed from a variety of materials that are partially reflective, such as various metals, such as chromium (Cr), semiconductors, and dielectrics. The partially reflective layer can be formed of one or more layers of materials, and each of the layers can be formed of a single material or a combination of materials. In some implementations, the optical stack 16 can include a single semi-transparent thickness of metal or semiconductor which serves as both an optical absorber and electrical conductor, while different, electrically more conductive layers or portions (such as portions of the optical stack 16 or of other structures of the IMOD) can serve to bus signals between IMOD pixels. The optical stack 16 also can include one or more insulating or dielectric layers covering one or more conductive layers or an electrically conductive/optically absorptive layer.
In some implementations, the layer(s) of the optical stack 16 can be patterned into parallel strips, and may form row electrodes in a display device as described further below. As will be understood by one having ordinary skill in the art, the term “patterned” is used herein to refer to masking as well as etching processes. In some implementations, a highly conductive and reflective material, such as aluminum (Al), may be used for the movable reflective layer 14, and these strips may form column electrodes in a display device. The movable reflective layer 14 may be formed as a series of parallel strips of a deposited metal layer or layers (orthogonal to the row electrodes of the optical stack 16) to form columns deposited on top of posts 18 and an intervening sacrificial material deposited between the posts 18. When the sacrificial material is etched away, a defined gap 19, or optical cavity, can be formed between the movable reflective layer 14 and the optical stack 16. In some implementations, the spacing between posts 18 may be approximately 1-1000 μm, while the gap 19 may be less than <10,000 Angstroms (Å).
In some implementations, each pixel of the IMOD, whether in the actuated or relaxed state, is essentially a capacitor formed by the fixed and moving reflective layers. When no voltage is applied, the movable reflective layer 14 remains in a mechanically relaxed state, as illustrated by the pixel 12 on the left in
The processor 21 can be configured to communicate with an array driver 22. The array driver 22 can include a row driver circuit 24 and a column driver circuit 26 that provide signals to, for example, a display array or panel 30. The cross section of the IMOD display device illustrated in
In some implementations, a frame of an image may be created by applying data signals in the form of “segment” voltages along the set of column electrodes, in accordance with the desired change (if any) to the state of the pixels in a given row. Each row of the array can be addressed in turn, such that the frame is written one row at a time. To write the desired data to the pixels in a first row, segment voltages corresponding to the desired state of the pixels in the first row can be applied on the column electrodes, and a first row pulse in the form of a specific “common” voltage or signal can be applied to the first row electrode. The set of segment voltages can then be changed to correspond to the desired change (if any) to the state of the pixels in the second row, and a second common voltage can be applied to the second row electrode. In some implementations, the pixels in the first row are unaffected by the change in the segment voltages applied along the column electrodes, and remain in the state they were set to during the first common voltage row pulse. This process may be repeated for the entire series of rows, or alternatively, columns, in a sequential fashion to produce the image frame. The frames can be refreshed and/or updated with new image data by continually repeating this process at some desired number of frames per second.
The combination of segment and common signals applied across each pixel (that is, the potential difference across each pixel) determines the resulting state of each pixel.
As illustrated in
When a hold voltage is applied on a common line, such as a high hold voltage VCHOLD
When an addressing, or actuation, voltage is applied on a common line, such as a high addressing voltage VCADD
In some implementations, hold voltages, address voltages, and segment voltages may be used which produce the same polarity potential difference across the modulators. In some other implementations, signals can be used which alternate the polarity of the potential difference of the modulators from time to time. Alternation of the polarity across the modulators (that is, alternation of the polarity of write procedures) may reduce or inhibit charge accumulation that could occur after repeated write operations of a single polarity.
During the first line time 60a: a release voltage 70 is applied on common line 1; the voltage applied on common line 2 begins at a high hold voltage 72 and moves to a release voltage 70; and a low hold voltage 76 is applied along common line 3. Thus, the modulators (common 1, segment 1), (1,2) and (1,3) along common line 1 remain in a relaxed, or unactuated, state for the duration of the first line time 60a, the modulators (2,1), (2,2) and (2,3) along common line 2 will move to a relaxed state, and the modulators (3,1), (3,2) and (3,3) along common line 3 will remain in their previous state. With reference to
During the second line time 60b, the voltage on common line 1 moves to a high hold voltage 72, and all modulators along common line 1 remain in a relaxed state regardless of the segment voltage applied because no addressing, or actuation, voltage was applied on the common line 1. The modulators along common line 2 remain in a relaxed state due to the application of the release voltage 70, and the modulators (3,1), (3,2) and (3,3) along common line 3 will relax when the voltage along common line 3 moves to a release voltage 70.
During the third line time 60c, common line 1 is addressed by applying a high address voltage 74 on common line 1. Because a low segment voltage 64 is applied along segment lines 1 and 2 during the application of this address voltage, the pixel voltage across modulators (1,1) and (1,2) is greater than the high end of the positive stability window (i.e., the voltage differential exceeded a characteristic threshold) of the modulators, and the modulators (1,1) and (1,2) are actuated. Conversely, because a high segment voltage 62 is applied along segment line 3, the pixel voltage across modulator (1,3) is less than that of modulators (1,1) and (1,2), and remains within the positive stability window of the modulator; modulator (1,3) thus remains relaxed. Also during line time 60c, the voltage along common line 2 decreases to a low hold voltage 76, and the voltage along common line 3 remains at a release voltage 70, leaving the modulators along common lines 2 and 3 in a relaxed position.
During the fourth line time 60d, the voltage on common line 1 returns to a high hold voltage 72, leaving the modulators along common line 1 in their respective addressed states. The voltage on common line 2 is decreased to a low address voltage 78. Because a high segment voltage 62 is applied along segment line 2, the pixel voltage across modulator (2,2) is below the lower end of the negative stability window of the modulator, causing the modulator (2,2) to actuate. Conversely, because a low segment voltage 64 is applied along segment lines 1 and 3, the modulators (2,1) and (2,3) remain in a relaxed position. The voltage on common line 3 increases to a high hold voltage 72, leaving the modulators along common line 3 in a relaxed state.
Finally, during the fifth line time 60e, the voltage on common line 1 remains at high hold voltage 72, and the voltage on common line 2 remains at a low hold voltage 76, leaving the modulators along common lines 1 and 2 in their respective addressed states. The voltage on common line 3 increases to a high address voltage 74 to address the modulators along common line 3. As a low segment voltage 64 is applied on segment lines 2 and 3, the modulators (3,2) and (3,3) actuate, while the high segment voltage 62 applied along segment line 1 causes modulator (3,1) to remain in a relaxed position. Thus, at the end of the fifth line time 60e, the 3×3 pixel array is in the state shown in
In the timing diagram of
The details of the structure of interferometric modulators that operate in accordance with the principles set forth above may vary widely. For example,
As illustrated in
In implementations such as those shown in
The process 80 continues at block 84 with the formation of a sacrificial layer 25 over the optical stack 16. The sacrificial layer 25 is later removed (see block 90) to form the cavity 19 and thus the sacrificial layer 25 is not shown in the resulting interferometric modulators illustrated in FIGS. 1 and 6A-6E.
The process 80 continues at block 86 with the formation of a support structure such as post 18 as, illustrated in
The process 80 continues at block 88 with the formation of a movable reflective layer or membrane such as the movable reflective layer 14 illustrated in
The process 80 continues at block 90 with the formation of a cavity, such as cavity 19 illustrated in
As shown in
As noted above,
The methods 91, 100, 200 and/or 210 can be implemented to process multiple substrates in any of a number of different ways. In some implementations, multiple substrates can be processed with method 91 and/or 100 in a batch within a process chamber in which the substrates are in open communication with one another and common reactant inlet(s) and exhaust(s). In some implementations, one or more of the process chambers (first, second and third process chambers, or etch, ALD and third chambers) can include an inner chamber and an outer chamber. In some implementations, one or more of the process chambers can include multiple inner chambers, or subchambers within the outer chamber. Each subchamber can be configured to process a single substrate. Processing within the subchambers can be conducted in parallel.
The batch cluster tool 110 can be controlled by a controller 115 configured to control the various functions of the load lock chamber 112, the transfer chamber 114, and the process chamber 116, to perform the desired wafer handling, reactant supply, process pressures, and processes. In some implementations the controller 115 includes a memory and a processor and is configured or programmed to perform the processes illustrated in
In some implementations the reactant sources 137a, 137b, and 137c are gas delivery systems or subsystems configured to contain, meter and deliver in the vapor phase reactants for the release etch, ALD layer deposition, and SAM deposition.
The process chambers in the batch cluster tool can be configured to perform different deposition processes. For example, the batch cluster tool can have process chambers configured for the etch/release, configured for the formation of an ALD layer, and configured for the formation of a SAM layer. The cluster tool can have one or more controller(s) programmed for performing each of the release, formation of an ALD layer, and formation of a SAM layer in the various process chambers. For example, a batch cluster tool with six processing chambers can include two process chambers configured for each of the etch, ALD layer formation, and SAM layer formation.
After the etch and release the processed substrates are delicate and sensitive to contamination. In some implementations cross contamination of process gases between the different processes is minimized. In some implementations the cluster tool provides minimal movement of process gases between different processes after the release. In some implementations relative pressures are chosen for the transfer chamber, process chambers, and reaction spaces to minimize cross-contamination among the different chemicals for the release, ALD process, and SAM formation.
In some implementations, the different process chambers can be arranged to minimize the transfer time of the substrates between the different processing chambers.
In some implementations the reaction spaces and/or process chambers are purged after processing the substrates and before opening the door between the process chamber and transfer chamber to minimize contamination between the different process chambers and process gases.
In some implementations transferring the substrate can include batch transfer of multiple substrates or an entire rack or boat containing multiple substrates. In some implementations transferring the substrate can include sequentially transferring individual substrates between the transfer chamber and the processing chambers. In some implementations the robot could have multiple paddles or end effectors to transfer multiple substrates at a time. In some implementations the robot could transfer racks or boats among chambers.
In some implementations a robot is used to transfer the substrates or racks between chambers. In some implementations the transfer robot can rotate and extend horizontally to move substrates or racks (such as boats) into or out of a process chamber or load lock chamber.
Different types of substrates can be transferred by the robot and accommodated by the racks. In some implementations rectangular substrates are used. In some implementations circular substrates are used. In some implementations glass substrates are used. In some implementations glass substrates for displays are used. In some implementations glass substrates for EMS displays are used. In some implementations glass substrates are used for IMOD displays. In some implementations the cluster tool, transfer robot, process chambers, subchambers described herein, or components thereof, such as lift pin assemblies, are configured to handle standard large format rectangular substrates, including G1 (˜300 mm×350 mm); G2 (˜370 mm×470 mm); G3 (˜550 mm×650 mm); G4 (˜730 mm×920 mm); G5 (˜1100 mm×1250 mm); G6 (˜1500 mm×1850 mm); G7 (˜1950 mm×2200 mm); G8 (˜2200 mm×2400 mm); G10 (˜2880 mm×3130 mm); In some implementations, the glass substrate may have a thickness of 0.3, 0.5 or 0.7 millimeters, although in some implementations the glass substrate can be thicker (such as tens of millimeters) or thinner (such as less than 0.3 millimeters). In some implementations, a non-glass substrate can be used, such as a polycarbonate, acrylic, polyethylene terephthalate (PET) or polyether ether ketone (PEEK) substrate. In such an implementation, the non-glass substrate will likely have a thickness of less than 0.7 millimeters, although the substrate may be thicker depending on the design considerations. In some implementations, a non-transparent substrate, such as a metal foil or stainless steel-based substrate can be used. In some implementations, the substrate may be or include silicon, or other materials used in IC manufacturing.
In some implementations the process chambers are configured to process five or more substrates at the same time. In some implementations the process chambers are configured to process from about 5 substrates to about 25 substrates. In some implementations more than 25 substrates can be processed simultaneously in the process chambers.
The reactants sources 137a, 137b and 137c can contain reactive process gases and inert gases for purging the reaction space. The process controller 115 can be configured to perform the depositions of the ALD layer and SAM layer. For example,
In some implementations the process chambers and reaction spaces can be used to etch a portion of the processed substrate. For example, the etch can be used for the release process. In some implementations a vapor phase etchant is used. In some implementations XeF2 is vaporized and provided to the reaction space to etch portions of the substrate.
In some implementations the example of a batch process chamber 116 shown in
In some implementations the batch process chamber 116 shown in
In some implementations the batch process chamber 116 shown in
The etchants chosen and the form of the reactant source 137a depend upon the sacrificial material employed in the fabrication of electromechanical systems devices. Fluorine-based etchants, such as XeF2, can selectively etch certain metallic and semiconductor sacrificial materials, such as tungsten (W), molybdenum (Mo) or silicon, without removing other exposed materials in an electromechanical systems device, such as silicon oxide, aluminum oxide and aluminum. The illustrated implementation includes a vessel holding solid XeF2 crystals and gas lines, valves, buffers and gas sources configured to vaporize and deliver etchant vapor to the reaction space 134. In particular, vapor and inert carrier gas (such as the illustrated nitrogen or N2 gas) are drawn into Buffer 1, which serves as an expansion chamber to aid vaporization of the XeF2 crystals. The pressure in Buffer 1 is reduced by way of a pump. Buffer 1 can periodically feed vaporized XeF2 to Buffer 2, which has a smaller volume than Buffer 1, in which co-etchants (such as the illustrated oxygen or O2 gas) and inert carrier gases can be mixed before being fed to the reaction space 134. The cluster tool's controller 115 (
In some implementations the pressure in the etch reaction space 134 during processing is from about 0.1 to about 5 Torr. In some implementations the release etch takes from about 10 minutes to about 60 minutes for the removal of sacrificial material (such as molybdenum) from a batch of substrates. The exhaust 140 from the reaction space 134 can be closed off after the target pressure is reached, and remain closed after etching reactant vapors are provided from the reactant source 137a. The substrates can soak in the backfilled reaction space 134 until the etchants are exhausted, in which case another cycle of vaporization and backfill can be conducted, or until the sacrificial material is fully etched.
In some implementations the parts defining the reaction space 134 of the release etch process chamber 116, such as the reactor shell 130, the platform 128 and the rack 118, are constructed out of materials that are resistant to XeF2-based etchants and any reaction by-products, such as aluminum, aluminum alloy, SS316, or Inconel. Quartz may be used, and may be coated with a coating that is further resistant to XeF2-based etchants, such as aluminum oxide or yttrium oxide. Aluminum oxide can be used, for example, as a window material for viewing the interior of these components. XeF2 can react with water to form corrosive compounds such as HF that can undesirably etch the substrate and reaction space materials. The cluster tool can be operated to minimize the risk of water contamination of the etch process chamber, such as from neighboring ALD process chambers and SAM chambers as described below, to avoid formation of undesirable by-products.
The reactants and the form of the reactant source 137b depend upon the desired material to be deposited. The illustrated implementation includes a vessel holding a metal reactant, such as trimethyl aluminum (TMA, (CH3)3Al) and an oxygen source vapor, such as water. The TMA and water can be delivered to the reaction space by alternate and sequential pulses by high speed valves, with intervening removal of reactants from the reaction space 134, such as by providing an inert gas to purge the reactor of the previous reactant. As TMA is naturally liquid, the vessel can also serve as a vaporizer, such as a bubbler. The TMA can adsorb on surfaces of the batch of substrates in one reactant pulse, and the water can react with the adsorbed species in a subsequent pulse to form a self-limited monolayer of aluminum oxide. In some implementations the reactants flow through the reaction space 134 to the reaction space's exhaust 140; in some implementations, the exhaust 140 is closed and the reaction space 134 backfilled in one or more of the reactant pulses. Multiple cycles can be performed to form an aluminum oxide layer having a desired thickness. In some implementations, the aluminum oxide layer has a thickness of about 3 Å to about 50 Å. In some implementations, the aluminum oxide layer has a thickness of about 40 Å to about 90 Å. In some implementations the aluminum oxide layer can be used as a seed layer to promote the subsequent formation of the SAM. The cluster tool's controller 115 (
In some implementations the pressure in the reaction space during the ALD process is from about 100 mTorr to about 1 Torr. In some implementations the deposition of the ALD layer or seed layers takes between about 10 and 80 minutes.
In some implementations multiple process gas inlets can be used with the reaction space to avoid mixing the process gases in the inlet lines.
In some implementations the ALD reaction space is made of a material that is resistant to TMA, water, and any reaction by-products, such as aluminum, aluminum alloy, SS316, quartz, or titanium and/or aluminum oxide. The surface of these materials may be treated, for example, through coatings (e.g., aluminum oxide or yttrium oxide), anodization or roughening (e.g., to prevent film peeling). The roughness can be 3 μm Ra. In some implementations the reaction space is periodically cleaned to remove aluminum oxide formed on the reaction space surfaces.
The illustrated implementation of the reactant source 137c includes a vessel for providing vapor phase monomer n-decyltrichlorosilane (DTS), a vessel holding water, expansion chambers for vaporizing each of these sources, inert carrier gas provided to the expansion chambers, and a source of ozone for post-deposition cleaning of the reaction space 134 defined by the shell 130 and the platform 128.
The load lock chamber 182 can be configured to handle a boat, rack, cassette, or otherwise configured to handle multiple substrates 120. The load lock chamber 182 can be configured to receive the multiple substrates through a door 181 from an outside loading platform (not shown). The substrates 120 can be transferred from the load lock chamber 182 through a door 183 into the transfer chamber 184 using a robot 185. The transfer chamber 184 is in selective communication with the load lock chamber 182 and the plurality of process chambers 186. The cluster tool 180 can include similar components and function substantially similarly as the other implementations of the cluster tools described herein, such as cluster tools 110, 150, 160, and 170 described above with respect to
Each process subchamber 186a-186h can be configured to individually process a subset of the multiple substrates 120. In some implementations, each process subchamber 186a-186h can be configured to process a single substrate. Each process subchamber 186a-186h can include one or more substrate supports 188a-188h to support a substrate. The substrate supports 188a-188h can include a base, one or more pins (e.g., lift pin assemblies, such as those described in more detail below with respect to
The process subchambers described herein can be sealed with respect to each other, apart from communication with their common inlet and outlet assemblies, during processing. In some implementations, the process gas delivery, vacuum and/or exhausts, and/or other process features, such as temperature, can be separately and selectively controlled with respect to each of process subchambers, to allow individual tuning of a process performed within each of the process subchambers. Moreover, selective control of flow into and out of individual subchambers, such as through controllable valves upstream and downstream of individual subchambers, can allow selectively taking one or more subchambers off-line in the event of any malfunction or damage, while still allowing continued processing of substrates in the remaining subchambers in parallel. In some implementations, the process subchambers can be configured to allow for simultaneous, parallel processing of multiple substrates with substantially similar process conditions.
Selective communication (e.g., for substrate transfer) can be provided to the interior of each of the subchambers described herein with individual movable covers, such as a lids (
Referring again to
Implementations of process tools that include process subchambers, such as subchambers 186a-186h (
Implementations of process tools that include process subchambers may include valves, accumulators, flow controllers, pressure controllers, sensors, and/or any of a number of different fluid power components to control the flow of gas to and from the subchambers. In some implementations, one or more accumulators may be positioned downstream of the reactant source, and upstream of the subchambers, to affect the flow the reactant into the subchambers. Such accumulator(s) can include a common pipe or buffer, or can include individual buffers, one for each subchamber. One or more valves may be positioned upstream and/or downstream of the accumulator, to selectively flow reactant to and from the accumulator(s). The valves can be controlled to vary the amount of reactant flowed into the subchambers (e.g., dosage) in a number of different ways, such as with time control, volume control, or pressure control.
A plurality of outlet valves 330a-330h can be positioned downstream of the primary conduit 336. Outlet valves 330a-330h can be configured to selectively flow reactant from the primary conduit 336 into subchambers 386a-386h, respectively, such that they control outlet flow from the accumulator(s). Outlet valves 330a-330h can be controlled by the controller 315 to open and close simultaneously, or at different times, with respect to each other. Outlet valves 330a-330h can allow one or more of subchambers 386a-386h to be taken individually offline, for example, while the others of subchambers 386a-386h continue to process substrates. A shut-off valve 340 can be positioned downstream of the gas source 337 and upstream of the primary conduit 336. Shut-off valve 340 can be configured to selectively flow reactant into the primary conduit 336.
In a time control dosage operation, outlet valves 330a-330h can be maintained in a closed position while reactant is allowed to flow into primary conduit 336 for a period of time (e.g., by keeping shutoff valve 340 open). After the period of time has lapsed, one or more of outlet valves 330a-330h can be opened, simultaneously or sequentially, allowing a dose of reactant to flow from one or more of outlet valves 330a-330h into subchambers 386a-386h, respectively. In some implementations, the outlet valves 330a-330h can be opened at different times (for example, sequentially, or staggered) with respect to each other, to reduce pressure drop within the primary conduit 336. After another period of time has lapsed, and a dose of reactant has been supplied into the one or more subchambers 386a-386h, the one or more outlet valves 330a-330h can be closed, simultaneously or sequentially. Through such a time control dosage operation, for relatively low pressure precursors, such as naturally liquid or solid precursors commonly used for ALD metallic or semiconductor precursors, vapor pressure can build in the primary conduit 336 between dosage deliveries (e.g., between ALD pulses), such that the primary conduit 336 can serve as an accumulator. It is understood that in some implementations, shutoff valve 340 can remain open during processing and only the outlet valves 330a-330h open and close.
The primary conduit 336 can have an inner cross-sectional area that is larger than an inner cross-sectional area of each of the plurality of secondary conduits 336a-336h. Such a configuration can allow for accumulation and relatively uniform distribution of flow into the multiple secondary conduits 336a-336h. Sizing the primary conduit 336 such that it forms an accumulator and distributor, and/or using the aforementioned time control dosage operation may be beneficial, for example, in an ALD process. For example, it may be beneficial to use such a configuration when the common reactant source 337 comprises an ALD reactant, such as trimethyl aluminum, or a semiconductor or other metal source. It may also be beneficial to duplicate such a configuration for other ALD reactants, such as a common oxidizing source, such as water, such that ALD reactant is provided with a separate path to each subchamber 386a-386h. In some implementations, process tool 380 can comprise an ALD tool in which the primary conduit 336 can form an accumulator with an inner cross-sectional area that falls within a range of approximately eight to twelve times greater than the inner cross-sectional area of each of the secondary conduits 336a-336h. In some implementations (for example, when process tool 380 is an ALD tool), the inner volume of the primary conduit can form an accumulator with a volume of 0.05 to 0.5 times the total volume of subchambers 386a-386h. It is understood that for ALD and other processes requiring two reactants, the subchambers 386a-386h shown in
The volume of the accumulator 410 can be selected to store sufficient volume of a reactant relative to a process performed within subchambers 386a-386h. For example, the accumulator 410 can include an inner volume that falls within a range of approximately 0.5 to 20 times, or in some implementations, 0.5 to 5 times a total inner volume of all of the subchambers 386a-386h. Using a single accumulator supplying all the subchambers, such as accumulator 410 may provide similar accumulation and distribution function as primary conduit 336, when primary conduit 336 is configured to act as a buffer chamber, as described above with reference to
In some implementations, process chamber 586 can be configured to perform a volume-control dosage operation. In a volume-control dosage operation, the volume of the buffers 510a-510h can be selected to store sufficient volume of a reactant relative to a process performed within subchambers 386a-386h. For example, each of buffers 510a-510h can include an inner volume that falls within a range of approximately 0.5 to 1.0 times an inner volume of each of the subchambers 386a-386h, for an etch process. In use, the outlet valves 330a-330h can be maintained in a closed position while reactant is flowed into one or more of buffers 510a-510h for a period of time (e.g., by keeping shutoff valve 340, and one or more of inlet valves 331a-331h open). After the period of time has lapsed, one or more, or in some implementations, all of valves 330a-330h can be opened, sequentially, or simultaneously, allowing a dose of reactant to flow from one or more of valves 330a-330h into subchambers 386a-386h, respectively. An exhaust valve (e.g., exhaust valves 327a-327h; shown in
After another period of time has lapsed, and a dose of reactant has been supplied into the one or more subchambers 386a-386h, the one or more valves 330a-330h can be closed, simultaneously or sequentially. In some implementations, the above steps can be repeated, to re-fill one of buffers and provide multiple doses from the buffer into a corresponding subchamber, for a single process cycle within a subchamber. The volume of buffers 510a-510h can generally be selected to allow a sufficient dosage of reactant to the subchambers 386a-386h for the process being performed therein. Implementing a volume-control operation may be beneficial, for example, in a release etch process. For example, such a configuration may be beneficial when the common reactant source 437 comprises an etchant source, such as a fluorine-based etchant, such as xenon difluoride. Additional description of a release etchant process, and the benefits to providing buffers to allow for expansion of etchants upstream of a process chamber is described above with reference to Buffers 1 and 2 shown in
Continuing to refer to
The first reactant source 537a and the second reactant source 537b can include reactants to form a self-assembled monolayer (SAM) on a substrate. In some implementations, the first reactant source 537a can include an organic source chemical, such as n-decyltrichlorosilane (DTS), and the second reactant source 537b can include an oxygen source, such as water. An inner volume of each of the first plurality of buffers 510a-510h may be sized, relative to an inner volume of each of the second plurality of buffers 610a-610h, based upon the type of reactant in reactant sources 537a, 537b. For example, in an implementation in which the first reactant source 537a includes an organic source chemical, and the second reactant source 537b includes an oxygen source with a higher vapor pressure than the organic source chemical, an inner volume of the one of the first buffers 510a-510h can be between approximately five and fifteen, or in some implementations, between about eight and twelve times greater than an inner volume of one of the second buffers 610a-610h. The inner volume of each of the first plurality of buffers and second plurality of buffers can also be sized relative to the inner volume of the subchambers. For example, because DTS has a relatively lower vapor pressure, the buffer size can be similar to the corresponding process subchamber. In some implementations, for DTS, the inner volume of each buffer can be approximately 0.1-2.0 times the size of the corresponding subchamber. In some implementations, for DTS, the inner volume of the buffers can be 0.2-0.5 times the size of the corresponding subchamber. For water, the buffer size can be smaller still; for example, the inner volume of each buffer can be approximately 0.01-0.1 times the inner volume of the corresponding subchamber.
Process tool 680 can be configured to perform a pressure-control dosage operation from reactant source 537a and/or 537b. In such an operation, the control system 315 can be configured to close outlet valve 330a, and open inlet valve 331a, to allow flow of reactant from the reactant source 537a into buffer 510a. The control system 315 can monitor pressure within buffer 510a with pressure sensor 517. After pressure within the buffer 510a reaches a threshold, the inlet valve 331a is closed, and the outlet valve 330a is opened, to flow a pressure-controlled dose of reactant from the buffer 510a into the subchamber 386a. The exhaust valve 327a can be maintained in a closed position during flow of the dose of reactant into subchamber 386, and/or during processing of a substrate within subchamber 386a. For example, the exhaust valve 327a may be closed during a soak or saturation process such as SAM or release etch. Similar operations can be performed on any of subchambers 386a-386h, using inlet valves 331a-331h, outlet valves 330a-330h, and exhaust valves 327a-327h, simultaneously or sequentially with respect to each other. Additionally, similar operations can be performed to provide a pressure-controlled dosage of reactant into subchambers 386a-386h from the second reactant source 537b, through buffers 610a-610h, using inlet valves 631a-631h, outlet valves 630a-630h, exhaust valves 327a-327h, and the pressure sensor 617. A pressure-control dosage operation may be beneficial within some processes, such as a SAM process. It will be understood that a pressure-control dose operation can be similarly employed with processes that may use precise dosing of two or more reactants, such as a SAM process, using the apparatus of
The inlet and outlet valves that control reactant flow into the subchambers described herein can include any of a number of types of valves suitable for the processes within the subchambers. For example, implementations in which valves (e.g., valves 630a-630h and 631a-631h) are used to control the dose of a higher vapor pressure reactant, such as water (e.g., in a SAM process), the inlet valve and/or the outlet valve may have a response time of approximately 5-30 ms, due to the higher vapor pressure. Implementations in which valves (e.g., valves 530a-530h and 531a-531h) are used to control the dose of a relatively lower vapor pressure reactant, such as DTS (e.g., in a SAM process), the inlet valve and/or the outlet valve may have a relative longer response time of approximately 70-150 ms.
In some implementations, the outlet valves can be closed before the pressure is balanced within the subchambers to prevent back diffusion from the subchambers into the buffers. For example, the flow rate through the outlet valves may be approximately 10-50 times faster than the rate of diffusion. The Peclet number, corresponding to gas flow rate/diffusion speed may be used to determine an approximate discharge pressure. In some implementations, the pressure at which the outlet valves may be opened, to release a pressure-controlled dose of reactant, may correspond to a point at which the Peclet number is greater than 50. A Peclet number above 50 may correspond to a point at which back diffusion from the process subchamber to the buffer chamber is at a sufficiently low value to avoid detrimental effects to the processes being employed, such as etch release or SAM deposition.
In some implementations, wherein the first reactant source 537a comprises an n-decyltrichlorosilane (DTS) source, the control system 315 can be configured to provide pressure-controlled doses of DTS to the subchambers 386a-386h from the first buffers 510a-510h. In some implementations, outlet valves 330a-330h can be kept closed until the pressure of DTS within subchambers 386a-386h is detected by pressure sensors 517 to fall within a range of approximately 0.3 to 0.5 Torr, at which point control system 315 opens outlet valves 330a-330h. In some implementations, the DTS can be controlled with a temperature sensor to fall within a temperature range of approximately 70-90 degrees C. In some implementations, wherein the second reactant source 537b comprises a water source, the control system 315 can be configured to keep outlet valves 630a-630h closed until the pressure detected by pressure sensor 617 falls within a range of approximately 25-37 Torr, upon which outlet valves 630a-630h can be opened, providing a pressure-controlled dose of water to at least one subchamber. In some implementations, the water can be controlled with a temperature sensor to fall within 20-40 degrees C.
Continuing to refer to
In some implementations, an additional gas supply can be configured to provide another gas, such as nitrogen or oxygen, into each of the buffers described herein. The additional gas supply can be controlled to a pressure within the buffers, similar to the pressure control described herein with respect to the reactants in the buffers. In some implementations, the additional gas supply can be mixed with reactant within the buffers.
Apparatus 780 can include a self-centering lift pin assembly 720 configured to extend through the pin hole 716. The lift pin assembly 720 can include a lift pin shaft 730 and a pin head 740. The lift pin shaft 730 can be received by a pin head channel 741 extending from a lower surface of the pin head 740. The lift pin assembly 720 can be mounted on a lift pin support 750, such that when lift pin support 750 is moved relative to the substrate support 700, the lift pin assembly raises and lowers a substrate supported by pin head 740, relative to the base 710. In some implementations, the pin head 740 and lift pin shaft 730 can be resiliently or elastically connected to each other, for example, with a spring 735.
Pin head 740 can include a flanged upper portion 742 configured to extend over and engage with seat 712 of substrate support 700. The flanged upper portion 742 of pin head 740 can include an outer tapered surface 744 configured to engage with a corresponding tapered portion 713 of seat 712. An o-ring or similar sealing element 715 that can provide sealing between pin head 740 and seat 712 of substrate support 700. Pin head 740 can include an inner tapered surface 746 configured to face the tapered opening 718 of the pin hole 716. The engagement between the inner tapered surface 746 of the pin head 740, and the tapered opening 718 can provide a self-centering function, to compensate for relative thermal expansion and allow proper seating for the pin head 740. Such relative thermal expansion can arise, for example, due to differences in thermal expansion between substrate support 700 and lift pin support 750 during processing. In some implementations, the angle of tapered surface 746 and tapered opening 718 can be different with respect to each other, such that an angle θ1 is formed therebetween, as shown, to further prevent misalignment. Angle θ1 can fall in a range, for example, between approximately 2 and 25 degrees. In another implementation, θ1 can be between approximately 2 and 15 degrees.
In some implementations, a movable element 760 can be attached to the lift pin shaft 730 and the lift pin support 750. The movable element 760 can be configured to allow for relative lateral movement between the lift pin shaft 730 and the lift pin support 750. Such movement can be provided in any of a number of different ways, for example, with a slot, groove, cam, linear actuator, bearings, slides, or other means or mechanisms suitable to allow relative lateral movement. In the illustrated implementation, the movable element 760 includes a body 762, within which a slider 764 can laterally move using bearings 766. One or more springs or other resilient members 768 can be positioned on sides of the slider 764, to provide some resistance of movement, and to provide for a return position once any misalignment due to relative thermal expansion, for example, is removed.
In some implementations, the lift pin shaft 730 and the lift pin support 750 can be floating with respect to each other, without a direct connection therebetween. For example, a spring can be attached between the lift pin head and the substrate support, to allow the lift pin head to return to its lowered position engaged with the seat on the substrate support. The lift pin shaft can be floating within the pin head channel, allowing for independent lateral motion between the shaft and the pin head, while still allowing the lift pin shaft to raise the lift pin head when moved longitudinally. Such implementations can also reduce misalignment between the lift pin assemblies and the pin holes on the substrate support. It will be understood that a plurality of lift-pin assemblies 720 mounted on the substrate support 750 can be employed. In some implementations, the number of lift pin assemblies and/or the surface area of the pin head for each lift pin assembly can be selected to sufficiently handle large format rectangular substrates described herein. Larger format substrates generally use more lift pin assemblies, and more lift pin assemblies can be better for robot handling by reducing substrate sagging. Thinner substrates may also use more lift pin assemblies. However, it can be useful to have fewer lift pin assemblies to avoid pin marks, which may affect processing and quality of the devices made with the substrate. For example, it will be understood that typically between about 4 and 14 pin assemblies are employed for loading/unloading large format rectangular substrates as described herein. The surface area of the pin head (such as pin head 740) may range from approximately 50 to 2500 mm2 to handle loading/unloading large format rectangular substrates as described herein.
In some implementations, the lift pin support 750 can include an upper and lower portion of two different materials, to improve the alignment with the substrate support 700. For example, the upper portion of the lift pin support can include the same material, or material with a similar coefficient of thermal expansion, as the substrate support 700, such as aluminum. Such an implementation can allow the upper portion of the lift pin support to expand similarly as the substrate support in response to changes in temperature, reducing misalignment therebetween. The lower portion of the lift pin support can include a stronger material, such as a ceramic or stainless steel, to provide added rigidity. The attachment between such upper and lower portions can be limited to a central attachment portion, with the radial portions extending outwardly therefrom allowed to “float” to prevent flexation of the upper and lower portions due to difference in thermal expansion coefficients.
In some implementations a process chamber with a reaction space for forming a SAM can be used as part of the batch tool. In some implementations a monomer for forming a SAM is used. The monomer can be an organic linear chain molecule having a hydrophobic tail and hydrophilic tail. In one implementation n-decyltrichlorosilane (DTS) and water are used to form the SAM. In some implementations the pressure in the reaction space when depositing SAMs is between about 100 mTorr and about 1 Torr. In some implementations depositing the SAMs takes between about 10 and about 90 minutes.
In some implementations the SAM reaction space can be cleaned using ozone or other reactive cleaner to prevent buildup on the walls of the reaction space. The cleaning can be performed in between processing of a batch of substrates or periodically after processing multiple batches of substrates. In some implementations ozone can be used for cleaning the surface of the ALD layer or other seed layer to remove any contaminants, such as hydrocarbons. Hydrocarbon contamination can be caused by exposure to a clean room atmosphere or breaking vacuum, or in some implementations can result from the ALD process if organic precursors are employed. The cluster tool's controller 115 (
An example of a suitable material for the reaction space for resistance to the post-deposition or periodic cleaning process is aluminum oxide, also known as alumina. In some implementations the SAM reaction chamber and/or process chamber can be lined with or coated with an anodized aluminum liner capable of resisting corrosion from HCl and any other by-products formed during the deposition of the SAM. In some implementations the SAM reaction chamber is resistant to ozone. In some implementations the liner can be made of sapphire, or single crystal alumina.
The process chambers and reaction spaces can be constructed of different materials based on the reactor configurations and process gases that are used. In some implementations the reaction space shell can be made out of quartz. In some implementations an IR heater can be used with a quartz or sapphire reaction space shell, particularly in implementations subject to highly oxidizing environments, such as the SAM batch process tool, in which activated oxygen species like ozone can be employed for post-deposition cleaning of the chamber. In some implementations the reaction space shell can be made out of stainless steel, titanium or aluminum. Such metal shells can include surface coatings or liners to better withstand processing associated with, for example, the release etch and ALD processes and any periodic cleaning processes for them. In some implementations the shell can be anodized aluminum, include an anodized aluminum liner or be coated with alumina. In some implementations the reaction space shell in the etch process chamber can be made out of aluminum or anodized aluminum. In some implementations the reaction space shell in the ALD process chamber can be made out of aluminum, quartz, or anodized aluminum. In some implementations the reaction space shell in the SAM process chamber can be made out of quartz, or anodized aluminum. Aluminum reactor walls can be obtained, for example, from S.U.S. Cast Products, Inc. of Logansport, Ind.
After the release/etch, the partially fabricated devices are sensitive to contaminants. For example, exposing the partially fabricated device to a clean room after the release and before the formation of the ALD layer and SAM layer can result in carbon contamination or other contaminants in the cavity that can degrade the properties of the finished IMOD device. The risk of contamination of the partially fabricated device can be lowered by handling the substrates at a reduced pressure and handling the substrates in a closed environment, such as the batch cluster tools 110, 150, 160, and 170 described above with respect to
In some implementations during processing the pressure in the inner process chamber is greater than the pressure in the outer process chamber during processing. For example, in the implementation of
In some implementations when transferring substrates the transfer chamber 114 pressure is greater than the pressure in the process chamber 116 and reaction space 134. In some implementations the pressure in the reaction space 134 is lowered before the reaction space 134 is opened to the process chamber 116. In some implementations the pressure in the reaction space volume 134 during processing is greater than about 10−2 Torr, while the pressure in the process chamber 116 and transfer chamber 114 when transferring substrates is less than about 10−4 Torr. In some implementations the pressure in the process chamber 116 and transfer chamber 114 when transferring substrates is less than about 10−7 Torr. In some implementations the pressure in the process chambers and transfer chamber when transferring substrates can be between about 10−5 Ton and 10−8 Torr. In some implementations transferring the substrates includes transferring the substrates from a source chamber to a destination chamber, wherein the source and destination chambers and any chamber in between the source and destination chambers are maintained at a pressure of less than 10−5 Torr during transferring.
The reaction space, for example reaction space volume 134, can be purged after a batch is processed therein to remove any process gases and by-products from the reaction space. An inert gas can be used as a purge gas to displace any reactive process vapors and volatile by-product remaining in the reaction space after processing the substrates. In some implementations, a vacuum pump can be used to decrease the pressure in the reaction space prior to opening the reactor space to the surrounding process chamber space.
It is faster to pump down the smaller volume of the reaction space 134 than it is to pump down the larger internal volume 132 of the process chamber 116. The internal volume 132 of the process chamber 116 can be maintained at a lower pressure than the processing pressure used in the reaction space 134 during processing. Thus, the time to reduce the pressure in the reaction space 134 prior to opening the shell 130 and unloading the substrates is shortened in comparison to the time that it would take to reduce the pressure in the larger process chamber internal volume 134. The transfer chamber 114 can also be maintained at pressure similar to the pressure used in the process chamber 116.
The process gases used in the different processes, such as the etch/release, ALD layer formation and SAM formation, can react together to form undesired by-products and/or be incompatible with the materials used for the reaction space and process chambers that perform the other processes. Purging of the reaction spaces can reduce the risk of cross contamination and avoid the formation of undesirable by-products formed by mixing process gases used in the different processes.
In another implementation the transfer chamber 114 can be maintained at a higher pressure than the internal volumes 132 of the process chambers 116 and the reaction spaces 134. An inert gas, such as nitrogen, can be provided to the transfer chamber 114 to maintain a pressure higher than the process chambers. The positive pressure in the transfer chamber 114 can prevent diffusion or the flow of gases from the process chamber to the transfer chamber to decrease the likelihood of cross contamination of process gases between the different process chambers and reaction spaces. Unlike the opposite pressure gradient, which can prevent flow into the reaction spaces, employing a higher pressure in the transfer chamber 114 can prevent interaction between residual process gases of different processes and thus prevent cross-contamination. In some implementations a high vacuum (low pressure) is used in the transfer chamber, process chamber, and reaction space. The high vacuum pressure can result in decreased molecules in the chambers and decrease the chance of cross contamination because of the lower numbers of molecules present in the chambers.
In some implementations the batch cluster tool can be used to process multiple substrates simultaneously, and to sequentially perform release/etch, ALD of an antistiction layer, and vapor deposition of antistiction SAM. An example of sequential processing will be described with reference to
After the substrates can be transferred into the second process chamber 154b, the platform 128 in the second process chamber 154b can be raised to engage with the reactor shell 130 in the second process chamber 154b. An ALD process can be conducted therein. For example a metal source vapor and an oxidant source vapor can be alternated to form an antistiction layer in the cavity left by the release/etch by ALD. In one implementation, TMA and water can be alternately and sequentially supplied to the multiple substrates to form aluminum oxide within the cavity formed during the etch process. The pulses of TMA and water can be separated by purge periods of flowing inert purge gas. After formation of the aluminum oxide layer the reaction space can be purged and a vacuum pump can be used to decrease the pressure in the reaction space to a pressure that can be about the same as the pressure in the surrounding process chamber. The platform 128 can be lowered and the substrates can be transferred from the second process chamber 154b into the transfer chamber 151 and into a third process chamber 154c by the transfer robot 152. After the substrates are transferred out of the second process chamber 154b, a new batch of substrates can be transferred into the second process chamber 154b and processed.
After the substrates are transferred into the third process chamber 154c, the platform 128 in the third process chamber 154c is raised to engage with the reactor shell 130 in the third process chamber 154c. An antistiction self-assembled monolayer (SAM) can be formed in the third chamber 154c over the antistiction layer left by the ALD process. In one implementation N-decyltrichlorosilane and water can be used to form the SAM layer on the aluminum oxide layers formed in the cavities on the substrates. After formation of the SAM the reaction space can be purged and a vacuum pump can be used to decrease the pressure in the reaction space 134 to a pressure that is about the same as the pressure in the surrounding process chamber interior volume 132. The platform 128 can be lowered and the substrates can be transferred from the third process chamber 154c into the transfer chamber 151 and into the load lock chamber 153 or another process chamber for further processing. After the substrates are transferred out of the third process chamber 154c, a new batch of substrates (such as from the second process chamber 154b) can be transferred into the third process chamber 154c and processed.
The display device 40 includes a housing 41, a display 30, an antenna 43, a speaker 45, an input device 48 and a microphone 46. The housing 41 can be formed from any of a variety of manufacturing processes, including injection molding, and vacuum forming. In addition, the housing 41 may be made from any of a variety of materials, including, but not limited to: plastic, metal, glass, rubber and ceramic, or a combination thereof. The housing 41 can include removable portions (not shown) that may be interchanged with other removable portions of different color, or containing different logos, pictures, or symbols.
The display 30 may be any of a variety of displays, including a bi-stable or analog display, as described herein. The display 30 also can be configured to include a flat-panel display, such as plasma, EL, OLED, STN LCD, or TFT LCD, or a non-flat-panel display, such as a CRT or other tube device. In addition, the display 30 can include an interferometric modulator display, as described herein.
The components of the display device 40 are schematically illustrated in
The network interface 27 includes the antenna 43 and the transceiver 47 so that the display device 40 can communicate with one or more devices over a network. The network interface 27 also may have some processing capabilities to relieve, for example, data processing requirements of the processor 21. The antenna 43 can transmit and receive signals. In some implementations, the antenna 43 transmits and receives RF signals according to the IEEE 16.11 standard, including IEEE 16.11(a), (b), or (g), or the IEEE 802.11 standard, including IEEE 802.11a, b, g, n, and further implementations thereof. In some other implementations, the antenna 43 transmits and receives RF signals according to the BLUETOOTH standard. In the case of a cellular telephone, the antenna 43 is designed to receive code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile communications (GSM), GSM/General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA), Evolution Data Optimized (EV-DO), NEV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), Evolved High Speed Packet Access (HSPA+), Long Term Evolution (LTE), AMPS, or other known signals that are used to communicate within a wireless network, such as a system utilizing 3G or 4G technology. The transceiver 47 can pre-process the signals received from the antenna 43 so that they may be received by and further manipulated by the processor 21. The transceiver 47 also can process signals received from the processor 21 so that they may be transmitted from the display device 40 via the antenna 43.
In some implementations, the transceiver 47 can be replaced by a receiver. In addition, in some implementations, the network interface 27 can be replaced by an image source, which can store or generate image data to be sent to the processor 21. The processor 21 can control the overall operation of the display device 40. The processor 21 receives data, such as compressed image data from the network interface 27 or an image source, and processes the data into raw image data or into a format that is readily processed into raw image data. The processor 21 can send the processed data to the driver controller 29 or to the frame buffer 28 for storage. Raw data typically refers to the information that identifies the image characteristics at each location within an image. For example, such image characteristics can include color, saturation and gray-scale level.
The processor 21 can include a microcontroller, CPU, or logic unit to control operation of the display device 40. The conditioning hardware 52 may include amplifiers and filters for transmitting signals to the speaker 45, and for receiving signals from the microphone 46. The conditioning hardware 52 may be discrete components within the display device 40, or may be incorporated within the processor 21 or other components.
The driver controller 29 can take the raw image data generated by the processor 21 either directly from the processor 21 or from the frame buffer 28 and can re-format the raw image data appropriately for high speed transmission to the array driver 22. In some implementations, the driver controller 29 can re-format the raw image data into a data flow having a raster-like format, such that it has a time order suitable for scanning across the display array 30. Then the driver controller 29 sends the formatted information to the array driver 22. Although a driver controller 29, such as an LCD controller, is often associated with the system processor 21 as a stand-alone Integrated Circuit (IC), such controllers may be implemented in many ways. For example, controllers may be embedded in the processor 21 as hardware, embedded in the processor 21 as software, or fully integrated in hardware with the array driver 22.
The array driver 22 can receive the formatted information from the driver controller 29 and can re-format the video data into a parallel set of waveforms that are applied many times per second to the hundreds, and sometimes thousands (or more), of leads coming from the display's x-y matrix of pixels.
In some implementations, the driver controller 29, the array driver 22, and the display array 30 are appropriate for any of the types of displays described herein. For example, the driver controller 29 can be a conventional display controller or a bi-stable display controller (such as an IMOD controller). Additionally, the array driver 22 can be a conventional driver or a bi-stable display driver (such as an IMOD display driver). Moreover, the display array 30 can be a conventional display array or a bi-stable display array (such as a display including an array of IMODs). In some implementations, the driver controller 29 can be integrated with the array driver 22. Such an implementation can be useful in highly integrated systems, for example, mobile phones, portable-electronic devices, watches or small-area displays.
In some implementations, the input device 48 can be configured to allow, for example, a user to control the operation of the display device 40. The input device 48 can include a keypad, such as a QWERTY keyboard or a telephone keypad, a button, a switch, a rocker, a touch-sensitive screen, a touch-sensitive screen integrated with display array 30, or a pressure- or heat-sensitive membrane. The microphone 46 can be configured as an input device for the display device 40. In some implementations, voice commands through the microphone 46 can be used for controlling operations of the display device 40.
The power supply 50 can include a variety of energy storage devices. For example, the power supply 50 can be a rechargeable battery, such as a nickel-cadmium battery or a lithium-ion battery. In implementations using a rechargeable battery, the rechargeable battery may be chargeable using power coming from, for example, a wall socket or a photovoltaic device or array. Alternatively, the rechargeable battery can be wirelessly chargeable. The power supply 50 also can be a renewable energy source, a capacitor, or a solar cell, including a plastic solar cell or solar-cell paint. The power supply 50 also can be configured to receive power from a wall outlet.
In some implementations, control programmability resides in the driver controller 29 which can be located in several places in the electronic display system. In some other implementations, control programmability resides in the array driver 22. The above-described optimization may be implemented in any number of hardware and/or software components and in various configurations.
The various illustrative logics, logical blocks, modules, circuits and algorithm steps described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system.
The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular steps and methods may be performed by circuitry that is specific to a given function.
In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus.
If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. In some implementations the methods illustrated in
Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, a person having ordinary skill in the art will readily recognize that such operations need not be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.
