The present application relates to material deposition technologies, and more specifically to continuous deposition systems.
Flexible sheet materials such as thin stainless steel foil, polymer web, and paper are widely used as substrates supporting thick films (˜100's microns) or thin films (˜10's to 100's nanometers) of other functional materials. Examples of common functional materials include metals, semiconductors, insulators, and inorganic, organic or composite materials. The functional materials can be deposited or coated by vacuum-based technologies (e.g. sputtering, thermal evaporation, electron-beam evaporation, plasma enhanced chemical vapor deposition and atomic layer deposition), or non-vacuum-based technologies (e.g. chemical bath deposition, spin-on, sol-gel, spray-on, screen printing and inkjet printing). Film process technology using flexible substrates is often called “roll-to-roll process” (RTR process), or “web process”. Roll-to-roll processes have been used in some traditional industries like food vacuum packaging, and are finding more and more applications in flexible electronics. Flexible electronics include flexible circuit boards, radio-frequency identifications (RFIDs), fingerprint sensors, flexible displays, transparent displays, touch sensors, touch screens, flexible solar cells and numerous emerging devices.
Referring to
The above described roll-to-roll process system suffers from a number of major drawbacks. Referring to
Moreover, it is very difficult to implement depositions of very different atmospheres in the same vacuum chamber. For example, atmospheres in vacuum chambers often differ significantly for regular sputtering depositions (only inert gas, e.g. argon is used) and reactive sputtering deposition (both inert and reactive gases, e.g. argon and oxygen gases). In another example, physical sputtering deposition and chemical vapor deposition also require different vacuum pressures (e.g. ˜5 mTorr and ˜500 mTorr respectively). Furthermore, the throughput of the web-based system 100 is limited by the slowest deposition source, which can significantly limit the productivity of the entire equipment.
Therefore there is a need for improved film deposition system that can provide improved process flexibility and higher throughput in processing of continuous substrates.
The present application discloses highly modularized processing systems using continuous flexible substrates. The disclosed processing systems offer flexibility in process, scalability from development, pilot to production, as well as higher productivity in mass production. The continuous flexible substrate may be flexible polymer webs, metal foils, papers, etc. The continuous flexible substrate can also serve as a carrier on which small, rigid substrates or low profile 3-dimentional workpieces are mounted.
The disclosed processing systems can accommodate process techniques having wide pressure requirements on a single continuous substrate in a processing system. The processing techniques can range from low pressure vacuum deposition processes to atmospheric wet solution-based processes for coating, spraying, printing, and surface treatments.
Because of their flexibility and modularity, the disclosed processing systems can fully utilize the process window of each process technique without causing interferences between different techniques.
The disclosed processing systems can eliminate or minimize cross contaminations that are usually associated with conventional single-chamber roll-to-roll processing systems.
Furthermore, unlike some conventional continuous-substrate systems, the throughput of a disclosed processing system is not limited by the rates of individual processes in the continuous workflow.
In one general aspect, the present invention relates to a processing system that includes a first processing module comprising: a first chamber; and a first processing source configured to deposit a first material on a web substrate; an isolation module, comprising: an isolation chamber; and one or more segregation walls that define a sequence of compartments in the isolation chamber, wherein the first chamber is connected to a first compartment in the sequence of compartments, wherein each of the one or more segregation walls includes an opening to allow the web substrate to pass through; a second processing module, comprising: a second chamber in connection with a last compartment in the sequence of compartments in the isolation module; and a second processing source configured to deposit a second material on the web substrate; and a transport mechanism configured to move the web substrate continuously through the first processing module, the isolation module, and the second processing module.
Implementations of the system may include one or more of the following. The first chamber and the isolation chambers can respectively include flanges that connect the first chamber and the isolation chamber, wherein the web substrate is transported through the flanges. The second chamber and the isolation chambers can respectively include flanges that connect the isolation chamber and the second chamber, wherein the web substrate is transported through the flanges. The first processing module can further include one or more vacuum pumps each configured to exhaust gas in one of the compartments in the isolation chamber. The first chamber can be exhausted to a first pressure when the first material is deposited on the web substrate, wherein the second chamber can be exhausted to a second pressure when the second material is deposited on the web substrate, wherein the first pressure is in a range between 1 mTorr to 500 mTorr and wherein the second pressure is in a range between 10 Torr˜760 Torr. The second processing source can deposit the second material on the web substrate by immersing the web substrate in a solution that contains the second material. The first chamber can be exhausted to a first pressure when the first material is deposited on the web substrate, wherein the second chamber can be exhausted to a second pressure when the second material is deposited on the web substrate, wherein a ratio of the first pressure to the second pressure is higher than 100. A ratio of the first pressure to the second pressure can be higher than 1000. The second processing source can deposit the second material on the web substrate by inkjet printing. The second processing source can include a shower-head that is configured to emit a chemical vapor to deposit the second material on the web substrate. The first chamber can be exhausted to a first pressure when the first material is deposited on the web substrate, wherein the second chamber can be exhausted to a second pressure when the second material is deposited on the web substrate, wherein the first pressure is in a range between 1 mTorr to 30 mTorr and wherein the second pressure is in a range between 10−4˜10−5 Torr. The first chamber can be exhausted to a first pressure when the first material is deposited on the web substrate, wherein the second chamber can be exhausted to a second pressure when the second material is deposited on the web substrate, wherein at least one of the compartments in the isolation chamber is kept at a third pressure higher than the first pressure and the second pressure by pumping in an inert gas in the one of the compartments. The third pressure the one of the compartments in the isolation chamber can be kept 1 mTorr˜5 mTorr at higher than the first pressure and the second pressure. The first processing source can deposit the first material on the web substrate by sputtering, thermal evaporation, electron-beam evaporation, plasma enhanced chemical vapor deposition, or atomic layer deposition. The web substrate can be made of a steel foil, a polymer web, and a paper web. The first processing module can further include a rigid substrate or a rigid workpiece on the web substrate, wherein an outer surface of the rigid substrate or the rigid workpiece is configured to receive the first material from the first processing source and the second material from the second processing source. The first processing module can further include a third processing source configured to deposit a third material on the web substrate, wherein the first processing source and the third processing source are configured to deposit the first material and the third material on opposite surfaces of the web substrate. The first material can be substantially the same as the third material.
In another general aspect, the present invention relates to a processing system that includes a first processing module comprising: a first chamber; and a first processing source configured to deposit a first material on a web substrate; a first isolation module, comprising: a first isolation chamber; and one or more segregation walls that define a sequence of compartments in the first isolation chamber, wherein the first chamber is connected to a first compartment in the sequence of compartments in the first isolation chamber, wherein each of the one or more segregation walls includes an opening to allow the web substrate to pass through; a second isolation module, comprising: a second isolation chamber; and one or more segregation walls that define a sequence of compartments in the second isolation chamber, wherein a last compartment in the first isolation chamber is connected to a first compartment in the sequence of compartments in the second isolation chamber, wherein each of the one or more segregation walls includes an opening to allow the web substrate to pass through; a second processing module, comprising: a second chamber configured to receive the web substrate from a last compartment in the sequence of compartments in the second isolation module; and a second processing source configured to deposit a second material on the web substrate; and a transport mechanism configured to move the web substrate continuously through the first processing module, the first isolation module, the second isolation module, and the second processing module.
In yet another general aspect, the present invention relates to a double-sided processing module that includes a chamber comprising an entry slit and an exit slit that are configured to pass through a web substrate, wherein the web substrate comprises a first surface and a second surface; a wrap-around roller configured to be in contact with the second surface of the web substrate; a transport mechanism configured to move the web substrate continuously through the entry slit, wrapped around wrap-around roller, and through the exit slit; a first processing source positioned upstream t the wrap-around roller, wherein the first processing source is configured to deposit a first material on the first surface of the web substrate; and a second processing source positioned downstream the wrap-around roller, wherein the second processing source is configured to deposit a second material on the second surface of the web substrate.
These and other aspects, their implementations and other features are described in details in the drawings, the description and the claims.
Referring to
In some embodiments, referring to
In some embodiments, referring to
In some embodiments,
The processing modules 200-500 depicted in
Continuing with
Still referring to
The isolation module 510 includes a segregation wall 520 that separates the isolation module 510 into two compartments, which can further reduce cross contamination between the processing modules 300, 400. The segregation wall 520 includes a slit to allow the web substrate 220 to pass through. The continuous web substrate can all carry small rigid substrates or low profile workpieces. The rigid substrates or low profile workpieces include outer surfaces configured to receive materials from the processing sources.
In some embodiments, the cross-contamination can be further reduced or eliminated by keeping the base pressure in the isolation module 510 slightly higher than the processing pressures in the processing modules 300 and 400. This can be implemented by introducing certain level of flow of inert gas (Argon, for example) into the isolation module 510 to maintain a slightly higher (e.g. 1˜5 mTorr higher) Argon partial pressure; inert gas molecules are thus drawn away from the isolation module 510 and towards the processing modules 300 or 400, wherein the Argon gas molecules are exhausted.
In some applications, a continuous web workflow can include processing steps that require drastically different pressures. For example, inkjet printing of polymer materials is often conducted in a reduced pressure nitrogen gas (e.g. ˜500 Torr). Catalytic chemical vapor deposition of polymer thin films is conducted in pressure of around 50 mTorr. A continuous-substrate processing system 700 shown in
The compartments 720-740 are differentially pumped by the vacuum systems. Differential pumping is a staged pumping scheme that is used to connect and maintain vacuum chambers of very different pressures. It can be described as follows. A vast majority of the gas that migrated from the processing module 750 via (extended) flanges 755 is first exhausted from the compartment 740 by its associated pumping system. The small amount residual gas migrated from the compartment 740 to the compartment 730 thorough the thin slit is again mostly removed by the vacuum pump connected to the compartment 730. The minute amount of gas material migrated from the compartment 730 to the compartment 720 is again removed by the vacuum pump connected to the compartment 720. Therefore, the pressures in the compartments 740, 730, 720 gradually decrease, which dynamically maintains pressure differential between the higher-pressure processing module 750 and the lower-pressure processing module 200. The number of sequentially connected compartments can be varied according to the needs of applications.
Depending on the processing techniques employed, the processing pressure in the processing module 200 can be ˜1 mTorr to 500 mTorr; accordingly, the pressure in the compartment 720 can be ˜10 mTorr to 5 Torr; that in the compartment 730 can be ˜100 mTorr to 50 Torr; and that in the compartment 740 can be ˜1 Torr to 100 Torr; finally, the pressure in the processing module 750 can be 10 Torr up to 760 Torr (at atmospheric pressure). In other words, the pressure ratio between the processing module 750 and the processing module 200 can be higher than 100, or higher than 1000.
The continuous-substrate processing system 700 can be expanded to include multiple differential pumping modules. Referring to
Devices and materials suitable for the disclosed continuous-substrate processing apparatus include OLEDs (organic light-emitting devices), metal oxide TFFs (thin film transistors), TCOs (transparent conductive oxides), RFID (radio frequency identification) tags, and encapsulation materials. Substrates compatible with the disclosed processing apparatus include flexible materials such as stainless foils, polymer webs, and paper, as well as small rigid substrates (e.g. silicon wafers, glass plates) or workpieces (e.g. coronary stents, drill bits and jewelries) that are carried by or attached to a continuous web or tape.
Only a few examples and implementations are described. Other implementations, variations, modifications and enhancements to the described examples and implementations may be made without deviating from the spirit of the present invention. For example, the disclosed apparatus and system can be suitable for other deposition or processing techniques that are not described in the examples above. The exact configurations (shapes, dimensions, orientations and layouts) of the processing modules, the isolation modules, and differential pumping modules can differ from the examples illustrated above without deviating from the spirit of the invention. The web substrate can be made of materials other than the examples described above.
Number | Date | Country | |
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61819001 | May 2013 | US |