Patent Application
20120064250
1. Field of the Invention
The present invention generally relates to a transport unit for transporting a print support in a plant for depositing print tracks on the print support and a method for transporting the print support through the plant for depositing the print tracks.
2. Description of the Related Art
It is well known to deposit one or more print tracks in predetermined patterns on a suitable substrate support using one or more successive printing steps. The printing steps may include silk-screening, ink jetting, laser printing or other similar processes. Suitable substrate supports include wafers with a silicon or alumina base. Such processes are typically automated by electronic processors, peripheral hardware or other electronic apparatus. Typically, each print track is deposited by a corresponding print station. These print stations may be disposed in succession on a single line. Each print station may be provided with at least one print head on which one print net/mask is mounted, for example for silk-screen printing. Each print track consists of a print paste or material which is suitably released by the print head onto the print support according to a predetermined printing pattern.
Substrates may be transported on conveyor belts made of porous material. During transport, the substrates may be suctioned to the conveyor belt by drawing a vacuum from below the belt. By transporting the substrates in such a manner, a predetermined position of the substrate may be maintained and the center of the print head will be centered on the substrate with respect to the print head. In some instances, the substrate may have holes therethrough. If the substrates have holes therethrough, the paste deposited by the print head is drawn inside the holes until the paste exits from the surface opposite the one where it was deposited due to the vacuum. Therefore, the conveyor belt will become indelibly stained with the print paste and must be frequently replaced to prevent the stains from adversely affecting the deposition on the substrates, such as imperfections in printing and causing unwanted conductive conditions on various surfaces of the substrates. Changing conveyor belts increases the manufacturing costs. Additionally, there is a high possibility of errors in positioning and in making the subsequent wafers.
Therefore, there is a need in the art to transport a print support in a plant for depositing print tracks on the print support, which minimizes both the downtime and the costs associated with replacing the conveyor belt. There is also a need in the art for reducing the negative effects of printing paste pulled through holes in the substrate and of incorrect positioning of the conveyor belt.
The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.
In one embodiment, an apparatus includes a transport device having at least a transport surface and an adhesive surface layer disposed on at least a portion of the transport surface at a location corresponding to where a print support (also referred to herein a substrate) is to be positioned during processing.
Embodiments of the invention may further provide a transportation apparatus, comprising a transport device having a transport surface, an adhesive layer disposed over at least a portion of the transport surface, wherein the adhesive layer has a contact surface on which at least a portion of a substrate can be received, a separation device having an edge that is positioned to separate a substrate that is disposed on the contact surface, and a mechanical actuator that is configured to move the adhesive layer relative to the separation device.
Embodiments of the invention may further provide a method for transporting a substrate, comprising disposing a substrate on a contact surface of an adhesive layer that is disposed over at least a portion of a transport surface of a transport device, moving the substrate and the transport device towards a print head, and positioning a printing mask disposed in the print head relative to the adhesive layer using an actuator.
In another embodiment, a method for transporting a print support in a plant for depositing print tracks on said print support, in which the plant is provided with at least a print station having at least a print head able to deposit said at least one print track onto said print support according to a predetermined pattern is disclosed. The method includes disposing a print support on a transport device having at least a portion covered with at least one adhesive surface layer, moving a transport device having at least a transport surface toward said print head and depositing material onto the print support from the print head.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
Embodiments discussed herein relate to a print support for use in a plant that deposits print tracks on the print support. Suitable methods for depositing the print tracks include silk-screening, ink jetting and laser printing. The methods are generally used to print conductive tracks comprising a multiple layer pattern by a printing process that is performed on one or more surfaces of a print support. The term “print support” as used herein will generally include various types of substrates, such as, for example, plate elements used to form electronic devices, wafers, foils, green tape circuits or substrates with a silicon base that can be used to produce photovoltaic cells. However, it is to be understood that a print support, or substrate, may also include other types of print supports typical of other fields in which a printing operation is utilized.
In accordance with the above purposes, a transport unit according to the present invention is utilized in a plant for depositing print tracks on a print support. The plant is provided with at least one print station having at least one print head able to deposit on the print support at least one print track in a predetermined pattern. The transport unit comprises a transport device having at least one transport surface. The transport surface faces toward the print head during processing and is the surface upon which the print support is disposed when transported.
According to one embodiment of the invention, the transport surface comprises at least a portion that is covered by at least one adhesive layer on which the print support is to be directly positioned. Suitable adhesives that may be used include polyvinyl chloride and polypropylene. The adhesive layer maintains the print support in a predetermined position with respect to the transport device during the transport through the print station. Additionally, the adhesive layer maintains the print support in a predetermined position during the printing step to help assure that the printed material is correctly positioned on the substrate. Thus, correct positioning of the print support with respect to the transport device is obtained by the adhesive surface layer as opposed to suction through the transpiring material as has been conventionally done. It is to be understood that the term “non-transpiring” as used herein refers to a material which is impermeable to a gas and to suction, i.e., a gas disposed on a first side of the material cannot be attracted by suction applied to a side of the material opposite to the first side. This means that, when the substrate is upon this material, it is retained by the adhesive, not by the suction from below. Thus, the term “transpiring” as used herein is the opposite of “non-transpiring”. Due to the use of the adhesive layer, even if the print support has through holes, the print paste used to define the print tracks is prevented from being drawn through the holes and depositing on the contact surface or transport surface of the transport device. Therefore, the risk that the print paste can deposit and/or stain the transport surface of the transport device is reduced or even eliminated. Thus, the risk of the print paste interfering with the printing process of subsequent print supports is reduced or even eliminated. Similarly, the print paste is prevented from interfering with the printing method of the support for which it was delivered. The embodiments discussed herein reduce to a minimum the downtimes for replacing the transport device, and therefore with lower costs and management expenses associated with operation. Additionally, repeatability from print support to print support is increased due to an increase in uniformity. Another advantage of the transport device discussed herein is the transport device does not need to create vacuum (e.g., a pressure below atmospheric pressure) and/or suction in order to keep the print support adherent to the transport surface.
In one embodiment, the transport device includes a conveyor belt covered on its transport surface with the adhesive surface layer. The adhesive surface layer comprises a water-repellent and non-transpiring material. The conveyor belt may be tensed and moved by two reels, such as a feed reel and a recovery reel, that are disposed upstream and downstream of the print head. The adhesive surface layer is disposed on the transport surface of the conveyor belt. The conveyor belt may have portions of its transport surface on which the adhesive surface layer is provided and portions where no adhesive surface layer is provided. During processing, a print support is disposed on each portion having the adhesive surface layer. In one embodiment, each portion of the conveyor belt is independently mobile with respect to the adjacent portions, so as to allow specific adjustment of each print support before the printing steps.
In one embodiment, the transport unit comprises a suction unit disposed below the conveyor belt, at least in a location below a corresponding print station, to ensure the correct position of the print support during the printing steps. In another embodiment, an independent adhesive belt, provided with the adhesive surface layer thereon, is disposed on the transport surface of the conveyor belt. According to one embodiment, the adhesive belt is disposed on only one surface of the conveyor belt. In another embodiment, the adhesive belt is disposed at least partly on both surfaces of the conveyor belt. In one embodiment, the conveyor belt is a closed ring and the adhesive belt is deposited onto the transport surface of the conveyor belt at a position upstream of the print head and removed at a position downstream of the print head. In such an embodiment, the transport unit can comprise a suction unit which is disposed below the transport surface to keep the adhesive belt close to the transport surface of the conveyor belt.
In another embodiment, the transport device includes a transport shuttle able to support and transport a print support through the operating stations of the plant. The transport shuttle has a conveyor belt 116 (
In another embodiment, the transport unit comprises a separator device that is disposed downstream of the print head. The separator device, such as the separation blade 190 shown in
Suitable print nests which may be utilized include print nests available from Applied Materials Italia S.r.l., which can contain a lamp or other similar optical radiation device in order to rear-illuminate the substrate positioned upon it so that it can be easily inspected and centered. It is to be understood that other print nests sold by other manufacturers may be utilized as well.
In the embodiment shown in
As shown in the embodiment of
In the embodiments shown in
As shown schematically in
In the embodiment shown in
As shown schematically in the plan views of the transport surface 160 illustrated in
With reference to
In one embodiment, the first conveyor 111 and/or the second conveyor 112 are automated substrate-handling devices which can be connected to a bigger production line, for example of the Softline™ instrument available from Applied Materials Italia S.r.l. which is connected to the plant 100. In one embodiment, the print heads 102 used in the plant 100 can be conventional silk-screen print heads available from Applied Materials Italia S.r.l., which are able to deposit the layers of tracks 200 in a desired pattern on the surface of a substrate 150 during a silk-screen printing process. It is to be understood that other automated substrate-handling devices and other silk-screen print heads, including those sold by other manufacturers, may be utilized.
In one embodiment, the print head 102 comprises a plurality of actuators 102A, (for example stepper motors or servo motors), which are in communication with a system controller 101 and are used to regulate the angular position and/or orientation (e.g., represented by reference numeral “A” in
In one embodiment, the print heads 102 are able to deposit a material containing metal or containing dielectric on a solar cell substrate with a width of between about 125 mm and 156 mm and a length between about 70 mm and 156 mm. In another embodiment, not shown, each print unit also comprises a drying oven to subject to treatment the material deposited on the substrate 150 by the print heads 102. In one embodiment, the substrates 150 are micro-crystalline silicon substrates used for solar cells. In another embodiment, the substrates 150 are ceramic green-tape substrates.
In one embodiment of the present invention, the plant 100 is a silk-screen printing plant and the print heads 102 include silk-screen printing components which are configured to silk-screen print a layer of tracks 200 of material according to a pattern on a surface of the substrate 150. In another embodiment, the plant 100 is an ink jet printing plant and the print heads 102 include ink jet printing components, which are configured to deposit a layer of tracks 200 of material according to a pattern on a surface of the substrate 150. In another embodiment, the plant 100 is a processing plant that includes components for removing material in the print head 102, like a laser for the ablation or etching of one or more regions on a substrate 150. In another embodiment, the plant 100 can comprise other substrate processing modules which require precise movement and positioning of the substrates 150 for processing.
The controller 101 facilitates the control and automation of the whole plant 100 and can comprise a central processing unit (CPU) (not shown), a memory (not shown), and auxiliary circuits (or I/O) (not shown). The CPU can be of any type of processor for computers that are used in industrial regulations to control different chamber processes and hardware devices (such as conveyors, detectors, motors, fluid delivery devices, etc.) and to monitor the system and chamber processes (like the position of the substrate, processing times, signal detectors, etc.). The memory is connected to the CPU, and can be one or more from among those easily available, such as a random access memory (RAM), a read-only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. The software instructions and the data can be encoded and memorized in the memory to command the CPU. The auxiliary circuits too are connected to the CPU to help the processor in a conventional manner. The auxiliary circuits can include cache circuits, feed circuits, clock circuits, input/output circuits, subsystems and suchlike. A program (or computer instructions) readable by the controller 101 determines which tasks can be performed on a substrate 150. Preferably, the program is a software readable by the controller 101, which comprises a code to generate and memorize at least information on the position of the substrate 150, the sequence of movement of the various components controlled, information from the TV cameras, and any other corresponding combination.
In the configuration of the plant 100 shown in
It is to be understood that, in association with the print head 102, TV cameras may be provided, and also rotation members and/or correction members, not shown, to verify and modify the position of the substrates 150 before and/or after each operating passage through the print head 102. It is clear, however, that modifications and/or additions of parts or steps may be made to the transport unit 300 and the method as described heretofore, without departing from the field and scope of the present invention. For example, it is to be understood that each print unit may include two or more print heads 102, depending on specific operating requirements. It also is to be understood that the conveyor belt 116 may comprise a plurality of separate portions of its transport surface 160 on which the adhesive layer 170 is applied independently, so that a relative substrate 150 can be disposed on each portion. Additionally, each portion of the conveyor belt 116 may be independently movable with respect to the adjacent portions, so as to allow a possible specific adjustment of each substrate 150 before the printing steps.
Although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of unit for transporting a print support in a plant for depositing print tracks on the print support and relative transport method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
| Number | Date | Country | Kind |
|---|---|---|---|
| UD2010A000163 | Sep 2010 | IT | national |
This application claims priority to Italian Patent Application number UD2010A000163, filed Sep. 13, 2010, entitled “Unitai Per Iltransporto Di Un Supporto Di Stampa In Un Impianto Per La Deposizione Di Tracce Di Stampa Su Tale Supporto Di Stampa, E Relativo Procedimento Per Il Transporto”, and also the benefit of U.S. Provisional Patent Application Ser. No. 61/441,676, filed Feb. 11, 2011, entitled “Method And Apparatus For Transporting A Print Support”, which are both herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61441676 | Feb 2011 | US |
