System and method for printing solder paste and other viscous materials at high resolution

Abstract

A system and method for printing or otherwise transferring dot-shaped portions of a material (e.g., a viscous material, such as solder paste) onto an intermediate substrate at a first printing unit, the intermediate substrate having the dot-shaped portions of material printed thereon being transferred to a second printing unit, and the dot-shaped portions of material being transferred from the intermediate substrate to a final substrate at the second printing unit. Optionally, the first printing unit includes a coating system that forms a uniform layer of material on a donor substrate, and at the first printing unit, the material is transferred from the donor substrate to the intermediate substrate in individual dot-shaped portions. Each of the first printing unit and the second printing unit may employ a variety of printing or other transfer techniques. The system may also include a material curing and imaging unit to assist in the overall process.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 969,233, filed on February 3, 2020, and U.S. Patent Application No. 16 / 807,489, filed on March 3, 2020. Technical Field

[0003] The present invention relates to a system and method for printing viscous material (such as solder paste), wherein the viscous material is initially printed onto a film at a medium print quality, and then the printed viscous material is transferred from the film to a substrate at a high resolution and high speed by a laser assisted deposition / laser dispensing system. Background Art

[0004] Surface mount technology (SMT) is an area of ​​electronic assembly used to mount electronic components to the surface of a printed circuit board (PCB), as opposed to conventional assembly where components are inserted through holes in the PCB. SMT was developed to reduce manufacturing costs and to make efficient use of PCB space. Due to the introduction of surface mount technology and increasing levels of automation, it is now possible to build highly complex electronic circuits into smaller and smaller components with good repeatability.

[0005] The surface mount soldering process involves placing the electrical contacts of an electronic component or substrate, a small amount of solder paste, and solder-wettable pads next to each other on a printed circuit board. The materials are then heated until the solder reflows, creating an electrical connection between the solder-wettable pads and the electrical contacts of the electronic component. Once the solder reflows, it forms an electrical and mechanical connection between the electronic component and the printed circuit board. This process has many advantages over other methods of interconnecting components, as components can be interconnected simultaneously, and the process is repeatable, low-cost, and easily adaptable to mass production.

[0006] One of the most important parts of the surface mount assembly process is applying solder paste to the printed circuit board. The goal of this process is to accurately deposit the correct amount of solder onto each pad to be soldered. Typically this is achieved by stencil or foil screen printing the solder paste, but it can also be achieved by jet printing. It is generally accepted that this part of the process, if not properly controlled, causes the majority of assembly defects.

[0007] Solder paste itself is a mixture of flux ingredients and powdered solder metal alloys that are used extensively in the electronics industry. At room temperature, solder paste is pliable enough so that it can be made to conform to almost any shape. At the same time, it is "sticky" enough to adhere to any surface it comes in contact with. These qualities make solder paste useful both for surface mount soldering and for forming solder bumps on electronic components such as ball grid array packages or on printed circuit boards.

[0008] Solder paste printing is a very critical stage in today’s surface mount assembly processes. When printing with a stencil or film, there are several items that can negatively impact the process, resulting in defects in the final product. For example, the stencil itself should be very accurate: a stencil that is too thick will result in solder bridge shorts, while a stencil that is too thin will result in insufficient solder being applied. Similarly, solder bridge shorts can occur when the stencil aperture size is too large, but insufficient solder paste will be applied when the stencil aperture size is too small. It is generally considered best to use a circular stencil aperture that is slightly smaller than the PCB pad size to prevent bridging defects during reflow. However, defects can occur during stencil production.

[0009] The squeegee used for screen printing should also be optimized: the squeegee angle affects the vertical force applied to the solder paste. If the angle is too small, the solder paste will not squeeze into the stencil holes. If the squeegee pressure is too low, the solder paste will not be applied cleanly to the stencil; if the squeegee pressure is too high, it will cause more solder paste leakage.

[0010] Another key point is that the higher the printing speed, the less time there is to apply solder paste through the stencil hole surface, so a higher printing speed may result in insufficient solder. In the current process, the printing speed should be controlled at So currently the maximum speed is limited by the printing process.

[0011] The use of jet printing in the process is limited because solder paste is a high viscosity thixotropic material, and jetting is therefore quite complicated because most jet heads are designed for low viscosity materials and are very prone to clogging. However, it can be seen from the extensive research in this field that jetting and dispensing is a very promising method. See for example: WO 2007 / 084888 A2, US PGPUB 2011 / 0017841 A1, US Patent No. 9,808,822 B2, and US Patent No. 8740040 B2. Although promising, jetting viscous materials will generate some degree of unwanted debris and form defects in the final assembly. Summary of the invention

[0012] The inventors have recognized that it is desirable to jet print solder paste material (or any other viscous material), but in a manner that does not cause defects in the final assembly. To this end, the inventors have developed systems and methods that separate the jetting process and the application process, thereby solving jetting failures while avoiding problems caused by screen printing processes. In one embodiment of the present invention, a solder paste printing system includes an initial printing of an intermediate substrate and a second high-precision, low-to-fragment-free printing of a final substrate. The system may include one or more imaging devices for monitoring and controlling various processes. The final product as well as the intermediate material may also include a curing setting.

[0013] In some embodiments of the present invention, the printing system includes a coating system, and the coating system forms a uniform layer of printing material on the substrate. In the presence of, the coating system may include a syringe of printing material and an air or mechanical pump that drives the material from the syringe to the donor or carrier substrate. Then, the donor substrate is moved to and through the clear gap between the roller or knife to form a uniform layer of printing material whose thickness is defined by the gap. Alternatively, the coating system may include a screen printing module, wherein the printing material is coated on a screen or stencil with a well-defined hole, and the printing material is transferred to the substrate in a soft or hard joint mode using a blade or a scraper. In other embodiments of the present invention, the coating system may include a dispenser or inkjet head, gravure or micro-gravure printing system, a slot die system, or a roller coating system for coating a substrate with a highly uniform printing material layer on the substrate. The coating system can be contained in a closed room with a controlled environment (cold or hot) to prevent solvents from evaporating from the printing material or prevent material oxidation, thereby extending the useful life of the material. Furthermore, the coating system may contain more than one material, thereby creating the possibility of printing multiple materials onto an intermediate substrate in a controlled sequence, and enabling the printing of more than one material onto a final substrate. Within the coating system, the donor substrate may be translated bidirectionally or otherwise in a controlled manner, such as while opening a gap between coating rollers, making it possible to re-coat the same area of ​​the donor substrate with printed material without contaminating the rollers, reducing or eliminating the amount of substrate consumed in the initial printing process, thereby avoiding waste.

[0014] In various embodiments of the present invention, the printed material can be a solder paste or other metal paste for printing electronic devices, a metal paste or a ceramic paste, a high viscosity material, a wax material, a polymer material or a mixture of polymer and monomer materials, a sensitive low viscosity material, a material that can be cured by ultraviolet light or heat, or a dryable material.

[0015] Either or both of the first and / or second printing processes may use a laser-based system that incorporates a high frequency laser to enable the ejection of material from one substrate to another. Either may use a laser-assisted deposition / laser dispensing system that rotates 0-90 degrees or 90-180 degrees from the main axis of the gravity field in which it is located, thereby simplifying the mechanical structure without reducing the printing quality.

[0016] In some cases, the first printing process may use an inkjet head system capable of jetting material directly onto the intermediate substrate, a dispenser head system capable of printing material directly onto the intermediate substrate, or an offset printer module, a gravure printing module, or another printer module capable of printing material directly onto the intermediate substrate. Alternatively, the first printing process may use a screen printing module, in which the material is coated on a screen or stencil of a film with well-defined holes, and a blade or scraper is used to transfer the material to the substrate in a soft or hard joint manner to create an array of dots on the substrate. In some embodiments of the present invention, after printing onto the intermediate substrate in the printing unit, the printed intermediate substrate may be further cured by UV light or dried by a heater, and the intermediate substrate is returned to the printing unit for a second (or additional) layer of printing.

[0017] In some embodiments of the present invention, the first printing unit includes a gap control unit configured to maintain a very well-defined gap between the donor substrate and the intermediate substrate. For example, as described in US PGPUB 2005 / 0109734 A1, US Patent No. 6,122,036A, WO 2016 / 198291 and EP 3,219,412 A1, a set of three actuators allowing translation and rotation are used at the corners of the control unit to maintain a very well-defined gap between the coated substrate and the intermediate substrate. Such actuators can be used at the corners of the control unit for both the coated substrate and the intermediate substrate to allow translation and rotation in two planes, where the two planes are independent of each other or ride on each other.

[0018] In another embodiment of the present invention, a very well-defined gap between the donor substrate and the intermediate substrate can be achieved by providing a fixed support below the intermediate substrate as part of the coating system frame. Alternatively, a very well-defined gap between the coating substrate and the intermediate substrate can be maintained by using a transparent solid substrate instead of a film as the intermediate substrate.

[0019] In some embodiments of the present invention, the intermediate substrate may be a continuous transparent film substrate, a transparent film substrate coated with a metal layer or a metal and dielectric layer, or a transparent solid substrate.

[0020] In some embodiments of the present invention, after the first printing, the intermediate substrate is moved from the first printing unit to the second printing unit by a motor. Thus, the intermediate substrate may be a continuous film substrate that can deliver the material printed on the first printing unit to the second printing unit by rolling. Alternatively, the intermediate substrate may be a transparent solid substrate that can deliver the material printed at the first printing unit to the second printing unit using a robot, with optional changes in direction in between.

[0021] In some embodiments of the present invention, the printed material is cured by ultraviolet light or dried by a heater during the movement of the printed substrate from the first printing unit to the second printing unit. In addition, the printed image can be processed by an imaging system. Such an imaging system can be a microscope or a charge coupled device (CCD), which can take pictures of the printing material points on the intermediate substrate and measure the points in two dimensions, and then transmit the measurement data to the second printing unit for accurate deposition on the final substrate. Alternatively, the imaging system can be a three-dimensional (3D) microscope, which takes pictures of the printing material points on the intermediate substrate and measures the points in three dimensions, and then transmits the measurement data to the second printing unit for accurate deposition on the final substrate. In another embodiment of the present invention, the imaging system is two microscopes or CCDs, which are arranged so that one can image the printing material points on the intermediate substrate and measure the points in two dimensions (e.g., length and width), while the other measures the points in the third dimension (e.g., height), and then all the measurement data are transmitted to the second printing unit for accurate deposition on the final substrate. In any case, the imaging system can be included before and / or after the second printing unit, and the image can be captured from the intermediate substrate, the final substrate, or from both. In one embodiment of the invention, an imaging system at the secondary printing unit may use mirrors to acquire images from the surface of the intermediate substrate and / or the primary laser channel printing unit to simultaneously image the target area and dot size of the final substrate.

[0022] In some embodiments of the present invention, the second printing unit can be a laser-based system that includes a high-frequency laser to enable the ejection of dots from the intermediate substrate to the final substrate by laser jet release, the system having a one-dimensional or two-dimensional (2D) array scanning laser. Alternatively, in some cases, the second printing unit may include only a deposition position, where the intermediate substrate is directly engaged with the final substrate. In any case, after printing on the final substrate on the second printing unit (or other means), the printed final substrate can be further cured by UV light or dried by a heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which:

[0024] Figure 1 Conceptually illustrated are systems configured in accordance with embodiments of the present invention that employ narrow gap or contact gap printing systems (even non-digital printing systems), pre-printing processing and / or inspection, and digital high gap printing to print viscous materials (such as solder paste) at high resolution and high speed.

[0025] Figure 2a and Figure 2b Schematically shows the Figure 1 The concepts shown in the overview outline aspects of the configured system.

[0026] Figure 3a-3e An alternative arrangement of a system configured according to the schematic diagram shown in Figure 2 is shown, wherein: Figure 3a An example of such a system based on laser-assisted deposition in a first printing unit is shown; Figure 3b An example of a similar system in a first printing unit based on a gravure non-digital printing system is shown; Figure 3c Additional details of example configurations of the system are presented; Figure 3d presents additional details of another example configuration of the system without gravity constraints; and Figure 3e Yet another configuration of a system for translation of a transparent solid substrate is shown.

[0027] Figure 4a and Figure 4b It is shown that according to some embodiments of the present invention, the material is placed on the film substrate by using a syringe ( Figure 4a ) and pass the material through a well-defined gap to form a uniform layer ( Figure 4b ), to create a uniform film process.

[0028] Figure 5a and Figure 5b An example of direct screen printing onto a film substrate according to some embodiments of the present invention is shown.

[0029] Figure 6 An example of printing material from a web screen using a laser assisted deposition / laser dispensing system is shown according to some embodiments of the present invention.

[0030] Figure 7 An example of printing dot material from a film substrate using a laser jet release system according to some embodiments of the present invention is shown.

[0031] Figure 8 Aspects of imaging points on a solid or film substrate using a primary laser channel or a mirror according to some embodiments of the present invention are shown.

[0032] Fig. 9 Aspects of printing stamps using multiple print layers and adding a UV curing system or dryer according to some embodiments of the present invention are shown.

[0033] Fig.10 An aspect of printing multiple materials in the same layer by adding a UV curing system or dryer according to some embodiments of the present invention is shown. DETAILED DESCRIPTION

[0034] Before describing the invention in detail, please refer to Figure 1, conceptually illustrates a system 10 configured in accordance with an embodiment of the present invention that employs a narrow gap or contact gap printing system (even a non-digital printing system) 12, a pre-printing process and / or inspection 14a, 14b, and digital high gap printing 16 to print viscous material (such as solder paste) at high resolution and high speed. As further described below, the narrow gap or contact gap printing system 12 performs an initial printing of the viscous material onto an intermediate substrate. As part of the pre-printing process and / or inspection 14a, 14b, the intermediate substrate may be viewed by one or more imaging devices to monitor and control the initial and subsequent printing processes. The intermediate substrate may then be used as part of a second high gap printing 16 of the viscous material onto a final substrate. This second printing procedure may also be viewed by one or more imaging devices, is very accurate, and has little to no debris formation. In one embodiment of this two-step printing procedure, the viscous material is distributed on the intermediate substrate in the form of dots (e.g., small, generally circular spots or droplets) by a first printing process, then moves through an imaging system and reaches a second printing process, where the dots (or at least some of them) are deposited on the final substrate.

[0035] The first printing process can be laser-assisted deposition or other laser dispensing printing, in which a fast-frequency laser is used to eject dots of viscous material from a uniform layer on a coating substrate (e.g., a donor substrate) onto (or into) an intermediate substrate. The ejection of the material is preferably performed in a well-defined and robust manner to minimize variations in dot size. In order to ensure that the viscous material is uniformly coated on the donor substrate, an optional coating system 18 can be used to coat the donor substrate before the donor substrate is provided to the first printing unit performing laser-assisted deposition or other laser dispensing printing. This coating system can be a conventional coating system, such as a coating system or a roller coating system based on a micro-gravure printer or a slot die coater. Alternatively, the coating system can be a coating system, a dispenser, or an inkjet system based on screen printing. In other embodiments, the coating system can be based on a syringe and gap system, in which the viscous material is dispensed from a syringe onto the donor substrate, and the donor substrate then passes through a well-defined gap, such as a gap formed by a blade or other type of obstacle or a pair of rollers or cylinders. After passing through the gap, a uniform layer of viscous material will appear on the donor substrate, and the laser-assisted deposition / laser dispensing system can eject dots of material from the coated donor substrate onto the intermediate substrate. After providing a uniform layer of viscous material for printing in the first printing process, the donor substrate can be returned to the coating system (e.g., in a loop or by linear translation) to be re-coated by the coating system to create a new uniform coating layer on the donor substrate for the next printing. The donor substrate can be a transparent film or other substrate with or without a metal (or other) coating.

[0036] Systems configured according to embodiments of the present invention can be used to print a wide variety of liquid and / or paste materials. However, the present invention provides particular benefits for printing highly viscous materials that cannot be well printed at high resolutions by other methods. For example, systems configured according to embodiments of the present invention have specific applications in printing solder pastes and other metal pastes and highly viscous polymers (e.g., acrylic, epoxy, and urethane-based adhesives, pastes, or waxes). The present invention can also be used in conjunction with the printing of sensitive materials, because the coated donor substrate can be kept in a controlled environment before the first printing process, thereby avoiding solvent evaporation or oxidation of the material to be printed. Such a space can also provide a controlled area for temperature-sensitive materials.

[0037] The first printing process need not employ a laser-assisted deposition / laser dispensing system. In some embodiments, the first printing process may employ a dispenser or inkjet head, or it may employ conventional 2D printing techniques, such as offset printing, gravure printing, or other printing techniques. The first printing process may also be performed using screen printing or a combination of these techniques.

[0038] The second printing process in which the viscous material is transferred from the intermediate substrate to the final substrate may utilize a laser jet release system. For example, where the viscous material is present on the intermediate substrate in the form of dots, a print head in the form of a laser jet release system may be used to selectively transfer some or all of the dots of the viscous material from the intermediate substrate to the final substrate. The laser jet release system may include a high frequency laser that is arranged to scan the intermediate substrate in two dimensions to spray the dots from the intermediate substrate to the final substrate. Alternatively, a direct transfer system may be used in which the intermediate substrate is directly engaged with the final substrate to transfer dots of the viscous material therebetween. After printing onto the final substrate, the viscous material may be cured by UV or infrared light provided by a curing unit, or it may be dried by a heater.

[0039] Figure 2a and Figure 2b Schematically shows the Figure 1 The concepts shown in the drawings outline aspects of the configured systems 20a, 20b. Each of these systems separates the jetting process of viscous materials from the application process, thereby resolving jetting failures while avoiding problems caused by traditional printing processes. Each system includes one or more imaging devices for monitoring and controlling the jetting and application processes. Figure 2b In the figure, the printing system 20b includes a coating system 22, which forms a uniform layer 26 of the material to be printed (e.g., a high viscosity material such as solder paste or other metal paste, ceramic paste, wax material or a mixture of polymer and monomer materials, or a sensitive low viscosity material) on a donor substrate 28.

[0040] In one embodiment of the invention, the coating system 22 includes an injector of the material to be printed, and an air or mechanical pump to drive the material from the injector onto the donor substrate 28. A motor is then used to move the donor substrate 28 toward a well-defined gap between rollers or knives to form a uniform layer 26 of the material to be printed having a thickness defined by the gap. In some embodiments of the invention, the donor substrate 28 can be translated bidirectionally in a controlled manner while opening the gap between the coating rollers, thereby providing the possibility to re-coat the same area of ​​the donor substrate 28 with the material to be printed without contaminating the rollers, and reducing or eliminating the amount of donor substrate consumed in the initial printing process, thereby preventing waste.

[0041] In other embodiments, the coating system 22 may include a screen printing module, wherein a screen or stencil having well-defined apertures is used to coat the donor substrate 28, to which a viscous material is applied using a blade or squeegee, wherein the viscous material is then transferred to the donor substrate 28 in a soft or hard bonded manner. Alternatively, the coating system 22 may include a dispenser or inkjet head to print the viscous material onto the donor substrate 28. Alternatively, the coating system 204 may be a gravure or micro-gravure printing system that coats the donor substrate 28 with a highly uniform layer of material to be printed 26. In one embodiment of the present invention, the coating system 22 is a slot die system that coats the donor substrate 28 with a highly uniform layer of material to be printed 26. In another embodiment of the present invention, the coating system 22 is a roller coating system that coats the donor substrate 28 with a highly uniform layer of material to be printed 26. Although not shown in detail, Figure 2a The printing system 20a may also include a coating system as part of the narrow gap / contact printing process 30, which forms the first printing process described above.

[0042] like Figure 2a As shown, in one embodiment of the invention, the narrow gap / contact printing process 30 (which may include a first printing unit 32, and optionally a coating system 22) is contained inside a closed unit with a controlled environment 34 (cold or hot) to prevent solvent evaporation from the material to be printed or to prevent oxidation of the material, thereby extending the pot life of the material. In some embodiments of the invention, the coating system 22 contains more than one material, thereby creating the possibility of printing multiple materials onto an intermediate substrate 36 in a controlled sequence, and making it possible to print more than one material on a final substrate 38.

[0043] The first printing unit 202 produces an area 24 of material to be printed on the intermediate substrate 36. In one embodiment of the present invention, a continuous transparent film substrate is used as the intermediate substrate 36 of the system. Alternatively, a transparent film substrate coated with a metal layer or coated with a metal and dielectric layer can be used as the intermediate substrate 36 of the system.

[0044] The first printing unit 32 used in the narrow gap / contact printing process 30 may include a laser-based system including a high frequency laser configured to eject a portion of the coating material layer 26 from the donor substrate 28 to the intermediate substrate 36 via a laser-assisted deposition / laser dispensing system. The laser-assisted deposition / laser dispensing system may be rotated 0-90 degrees or 90-180 degrees from the main axis of the gravity field in which it is located, thereby making the machinery simpler without reducing the printing quality.

[0045] Alternatively, without using a coating system, the first (e.g., narrow gap / contact) printing process 30 may employ an inkjet head system capable of ejecting the material to be printed directly onto the intermediate substrate 36. Alternatively, the first printing process may employ a dispenser head system capable of printing the material directly onto the intermediate substrate 36. Alternatively, the first printing process may employ an offset printer module, a gravure printing module, or any conventional printing technique to print the material directly onto the intermediate substrate 36. For example, the first printing process may employ a screen printing module, wherein the material to be printed is coated on a screen or stencil of a film having well-defined apertures, and a blade or squeegee is employed to transfer the material to the intermediate substrate 36 in a soft or hard engagement manner to form an array of dots 40 of printed material on the intermediate substrate 36.

[0046] In some embodiments of the present invention, the first printing unit 32 employed in the narrow gap printing process 30 includes a very well-defined gap control unit between the donor substrate 28 and the intermediate substrate 36. In one example, as described in USPGPUB 2005 / 0109734 A1, U.S. Patent No. 6,122,036A, WO 2016 / 198291, and EP 3,219,412 A1 (incorporated herein by reference), a set of three actuators are used at the corners of the control unit to maintain a very well-defined gap between the donor substrate 28 and the intermediate substrate 36. A set of three actuator units can be used at the corners of the control unit for both the donor substrate and the intermediate substrate to allow translation and rotation in two planes, where the two planes are independent of each other or ride on each other. Alternatively, a very well-defined gap between the donor substrate 28 and the intermediate substrate 36 can be maintained by providing a fixed support under the donor substrate 28 and / or the intermediate substrate 36. Alternatively, a very well-defined gap between donor substrate 28 and intermediate substrate 36 may be maintained by using a transparent solid substrate as intermediate substrate 36 rather than a film.

[0047] In some embodiments of the present invention, after printing onto the intermediate substrate 36 in the first printing unit 22, the printed intermediate substrate is returned to the first printing unit 32 for printing of a second (or additional) layer of viscous material. In any case, after printing with the viscous material (in the form of dots 40 or other areas 24), the intermediate substrate 36 is moved from the first printing unit 32 to the second printing unit 44. In some cases, the second printing unit can be a selective release system 46 (e.g., a laser-based system) with an online inspection unit 48. The intermediate substrate can be moved by a motor, for example, in the case where the intermediate substrate is a film or similar substrate, or in the case where the intermediate substrate is a continuous film substrate, it can be rolled to transport the material printed at the first printing unit to the second printing unit. In one embodiment of the present invention, the intermediate substrate 36 is a transparent solid substrate, and the material printed at the first printing unit can be transported to the second printing unit using a robot, and the direction can be optionally changed in between.

[0048] In some embodiments of the present invention, the material printed on the intermediate substrate (which may be a material curable by ultraviolet (UV) light or a heater) may be cured by UV light or dried by a heater while the intermediate substrate 36 is being moved from the first printing unit 32 to the second printing unit 44. Furthermore, the material printed on the intermediate substrate may be processed by the imaging system 50 while the intermediate substrate 36 is being moved from the first printing unit 32 to the second printing unit 44.

[0049] Such an imaging system 50 may be one or more microscopes, charge coupled devices (CCDs), and / or other imaging components, other of which take pictures of the printed material dots 40 on the intermediate substrate 36 and measure the dots in two or three dimensions. For example, the imaging system 50 may include two microscopes or CCDs arranged so that the printed dots on the intermediate substrate can be imaged and measured in two dimensions (e.g., length and width), and the other measures the dots in a third dimension (e.g., height). This measurement data may then be transmitted to the second printing unit 44 to ensure accurate deposition of the viscous material on the final substrate 38. For example (e.g., Figure 2a), optical or other imaging inspection may reveal that, while many of the dots 40 are suitable for transfer to the final substrate 38 (e.g., represented by a check mark in the figure), some of the dots 40 have an undesirable shape or are unsuitable for transfer to the final substrate 38 due to other factors (e.g., represented by an "X" in the figure). A controller (not shown) that can access this data can then operate the second printing unit to skip transferring the unsuitable ones of the dots 40 to the final substrate. An imaging system may be included before and / or after the material transfer area of ​​the second printing unit 44, and the imaging system may capture images from the intermediate substrate 38, the final substrate 38, or both. In one embodiment of the present invention, the imaging system is located at the second printing unit 44, and may use a mirror or other optical component to obtain an image from the surface of the intermediate substrate 36 and / or the laser channel 52 of the second printing unit 44 to simultaneously image the dot size and the final substrate print area using the in-line inspection system 48.

[0050] As described above, the second printing unit 44 can be a laser-based system, such as a system including a high-frequency laser configured to eject dots 40 of the appropriate material from the intermediate substrate 36 to the final substrate 38 (under the control of the controller) via a laser jet release. In some embodiments of the present invention, the second printing unit can be a laser jet release system having a two-dimensional (2D) array scanning laser configured to scan the laser beam in a raster-like pattern as the intermediate substrate 36 passes through the target area to release the appropriate dots 40 of material onto the final substrate 38. Such a laser jet release system can be rotated 0-90 degrees or 90-180 degrees from the main axis of the gravity field in which it is located, thereby making the machinery simpler without reducing the printing quality.

[0051] In some embodiments of the invention, there is no second printing unit per se, but only a deposition position, where the intermediate substrate 36 directly engages the final substrate 38, and the material dots 40 are transferred by such contact between the intermediate substrate 36 and the final substrate 38. In either case (laser transfer or direct contact transfer), after printing onto the final substrate, the printed material can be further cured by UV light or dried by a heater.

[0052] Figure 3aAn example of a system 60 configured in accordance with the present invention is shown. The system 60 instantiates aspects of the systems 20a and 20b described above. In particular, the system 60 includes a coating system 22 that drives a material 62 from a reservoir (e.g., a syringe 64) onto a donor substrate 28 using air or a mechanical pump (not shown) to form a uniform layer 26 of the material to be printed on the donor substrate 28. The donor substrate 28 is then moved toward a well-defined gap 70 between rollers or knives 72 using rollers or gears 66 to form a uniform layer 26 of the material to be printed on the donor substrate 28 having a thickness defined by the gap 70.

[0053] The system 60 also includes a first printing unit 32 configured to produce dots 40 of material 62 on the intermediate substrate 36. In this example, the donor substrate 28 may be a transparent film, and the first printing unit 32 includes a first laser module 74 containing a high frequency laser arranged to eject portions of the coating material layer 26 from the donor substrate 28 to form the dots 40 on the intermediate substrate 36 by focusing the laser beam onto the interface between the material layer 26 and the intermediate substrate 36. The incident laser beam causes local heating, followed by a phase change and high local pressure, which drives the printing material to be ejected onto the intermediate substrate 36. After printing onto the intermediate substrate 36 in the first printing unit 32, the printed intermediate substrate may be returned for printing of a second (or additional) layer of material 62 by reversing the direction of the roller or gear 66 or continuing the movement of the intermediate substrate 36 through the coating system 22 in a cyclic manner.

[0054] Alternatively, donor substrate 26 may be a screen or mesh, wherein material 62 is introduced into the holes of the screen by applicator 72, which may be a roller or a blade. In this case, an incident laser beam from laser module 74 causes the material to be printed to be displaced from the holes in the screen to the intermediate substrate 36.

[0055] Once the dots 40 are printed on the intermediate substrate 36, the dots are moved toward the second printing unit 44, such as by moving the intermediate substrate 36 using rollers or gears 78. Although not shown in this figure, the intermediate substrate can be a film substrate that moves in a continuous loop so that the image of the material can be printed thereon at the first printing unit 32, then transferred to the final substrate 38 at the second printing unit 44, and thereafter the exposed intermediate substrate is returned to the transfer area of ​​the first printing unit 32 to receive new dots 40 of material.

[0056] During the movement of the intermediate substrate 36 from the first printing unit 32 to the second printing unit 44, the dots 40 of the material can be cured by UV light (not shown) or dried by a heater (not shown). Furthermore, during the process of the intermediate substrate 36 moving from the first printing unit 32 to the second printing unit 44, the dots of material printed on the intermediate substrate can be processed by the imaging system 50. It includes one or more 3D 80 and / or 2D 82 imaging components, which take pictures of the printed dots 40 of the material and measure the two-dimensional or three-dimensional dots. This measurement data can then be used by the second printing unit 44 to ensure accurate deposition of the material on the final substrate 38.

[0057] The second printing unit 44 may include a laser module 84 with an in-line inspection unit 48. When the intermediate substrate 36 moves to the target area 86 of the second printing unit 44, the laser module 84 is activated to emit a laser beam incident on the intermediate substrate 36 to transfer the material printed at the first printing unit to the final substrate 38. The in-line inspection unit 48 positioned at the second printing unit 44 includes a mirror 88 or other optical components for obtaining an image from the surface of the intermediate substrate 36 to help align the final substrate under the target area 86 through a platform 90 configured to move in two or three dimensions, and to help synchronize the pulses of the laser module 84 when the material dots 40 on the intermediate substrate 36 are in the target area 86. In some embodiments of the present invention, the laser module 84 of the second printing unit 44 may be configured to scan the laser beam in a raster-like pattern over the intermediate substrate 36 as the laser beam passes through the target area 86, thereby releasing the appropriate material dots 40 onto the final substrate 426. The material may pass through a UV curing system and / or drying system on the way to the second printing unit 44 , and / or UV curing and / or drying may be used after the material is printed on the final substrate 38 .

[0058] An alternative arrangement of the first printing unit 32 is Figure 3b. In this example, a system 92 configured in accordance with the present invention includes a coating system 22 in which a material 62 is driven from a reservoir, such as a syringe 64, onto a roller 94 using air or a mechanical pump (not shown). The thickness of the material layer on the roller 94 can be made uniform using one or more knives 98 at a certain distance above the surface of the roller 94. The roller 94 can be recessed or otherwise formed with a recess to contain a defined amount of material to be printed, which is transferred to the printing roller 96 when the two rollers contact each other in the material transfer area 100. Alternatively, the roller 94 can have a screen or grid-like surface with holes, and the material 62 is introduced into the holes. The roller 96 can contact the screen to achieve the transfer of the material to the screen. When the roller 96 completes its rotation through the printing area, it transfers the material in the form of dots 40 to the intermediate substrate 36. After the material is transferred from the roller 94, the roller passes through the inspection area 104, and any residual material can be removed using the knife 104 or other tool before a new layer of material is applied. The remaining components of the system 92 are as described above with respect to Figure 3a The system 60 shown is described.

[0059] Figure 3c Another embodiment of the present invention is shown. In this system 110, the coating system 22 forms a uniform layer of the material to be printed on the donor substrate 28, for example using one of the above-described techniques. Then, the first printing unit 32 prints the material from the uniform layer on the donor substrate 28 onto the intermediate substrate 36. In this example, a very defined gap 112 can be maintained between the coated donor substrate 28 and the intermediate substrate 36 by using a fixed support 114 below the intermediate substrate 36 near the first printing unit 32. The remaining components of the system 110 are as described above, and in this example, the positioning of a UV curing system and / or drying system 116 is shown, which is used to cure the material on the intermediate substrate on the way to the second printing unit 44. A post-second printing imaging system 118 for the intermediate substrate 36 is also shown, which can be used to ensure that the second printing unit 44 properly transfers the material from the intermediate substrate to the final substrate 38.

[0060] Figure 3d A system 120 is shown, which is configured to Figure 3c The system 110 shown in is substantially similar, except that in this configuration, the first printing performed by the printing unit 32 is performed at 90 degrees (or any other orientation) to the gravitational field in which the first printing unit is located. For example, in the illustration, the gravitational field is assumed to be from the top of the page to the bottom of the page, and the first printing unit is configured to print material from the donor substrate 28 to the intermediate substrate 36 at an angle orthogonal to the gravitational field. This arrangement provides a compact and simple configuration compared to the laser assisted deposition / laser dispensing system print head and some of the other printing systems described above.

[0061] As mentioned above, the intermediate substrate 36 may be a film, but in other cases it may be a transparent solid substrate 124 to ensure better alignment and synchronization between the first printing unit and the second printing unit. Figure 3e Printing from a coated donor substrate 28 onto a transparent solid substrate 124 is shown (left view), which is then flipped over to create a target for a second printing unit 44 where it is used to print onto a final substrate (right view).

[0062] Figure 4a and Figure 4b It is further shown that according to some embodiments of the present invention, a quantity of material 62 is placed on the film substrate 28 ( Figure 4a ) and passing the material through a well-defined gap 126 to form a uniform material layer 26 ( Figure 4b ), to create a process of uniform material layer 26. A well-defined gap 126 is created by bringing a pair of rollers 128a, 128b or knives close together using a suitable control unit (e.g., a stepper motor or piezoelectric transducer).

[0063] Figure 5a and Figure 5b An example of direct screen printing onto a film substrate, such as an intermediate substrate 36, is shown according to some embodiments of the present invention. In this technique, droplets 132 of a highly viscous material are printed from a screen or mesh 130 to form 2D and / or 3D structures on a receiving substrate, such as a film 134. Initially, a substantially uniform layer of viscous material is coated on a meshed delivery screen 130 and held within its open spaces 140 by adhesion to the screen surface and surface tension. The material-coated mesh 130 is then brought to a work area and contacted with a blade 136, which passes through the holes of the mesh, thereby ejecting the droplets 132 across the small gaps 142 onto the film substrate 134. Alternatively, the droplets 140 may be printed directly onto the substrate 134 by contacting the droplets 140 with the meshed delivery screen 130. Regardless of the printing technique used, printing may occur one drop at a time, or one layer at a time.

[0064] The openings 140 in the wire mesh 130 are preferably uniform in size (or close to uniform in size) and can have regular shapes (e.g., circular, square, rectangular, oval, triangular, etc.) or irregular shapes. The wire mesh 130 is typically made of metal (e.g., metal foil), but can be made of other materials, including but not limited to plastic, nylon, glass, quartz, etc. In some embodiments, the wire mesh can be made of plastic foil, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyimide (e.g., Kapton TM). The mesh structure of the wire mesh can be formed by laser drilling; in this way, the thickness of the wire mesh and the size of the openings in the wire mesh can be controlled independently of each other. Preferably, the wire mesh 130 is made of a flexible material so that it can be accommodated on an endless conveyor, but in other embodiments, a more rigid wire mesh can be used as a conveying mechanism that can accommodate the wire mesh (for example, an actuator that can move the entire wire mesh in one or two dimensions in a plane at a time). Therefore, the wire mesh 130 is a regular array of openings 140 in each of two planar dimensions and is maintained in tension by appropriate actuators 138 to help release viscous materials depending on the shape and volume of the openings and the viscosity and composition of the material filling the openings.

[0065] Figure 6 An example of printing material from a mesh screen 156 using a laser assisted deposition / laser dispensing system 150 is shown in accordance with some embodiments of the present invention. In this embodiment, a laser 152 is used to generate droplets 154 of a high viscosity material that, when solidified in an aggregate, form 2D and / or 3D structures on a receiving substrate (not shown in this view). In this technique, a substantially uniform layer of viscous material is coated on a mesh screen 156 and held within its open spaces by adhesion to the mesh surface and surface tension. The material-coated mesh is then brought to a work area and the material within the holes of the mesh is heated using a laser 152, causing the droplets to eject. More specifically, a focused laser beam is made incident on a thin layer of viscous material at a small work area, and this thin layer of material is delivered to the work area using a mesh screen 156 having small holes or other openings arranged therein in a periodic manner. As described above, the openings in the screen may have a desired size, and may be regular (e.g., circular, square, rectangular, elliptical, triangular, etc.) or irregular in shape, depending on the application. The mesh can be made of metal (e.g., metal foil) or other materials, including but not limited to plastic, nylon, glass, quartz, etc. Preferably, the mesh is made of a flexible material, but in other embodiments, a more rigid mesh can be used as a transport mechanism that can hold the mesh (e.g., an actuator that can move the entire mesh in one or two dimensions in a plane at a time). When laser light is focused on an opening (or an area adjacent to the opening) in the mesh mesh 156 through a transparent (at least at the laser wavelength of interest) substrate 158, the material in the opening is heated, causing droplets 154 to be ejected toward the substrate (not shown in this view). The size of the droplets 154 is approximately the same as the size of the opening in the mesh mesh 156, and its volume is approximately equal to the volume of the material contained in the opening. As the mesh mesh 156 is transported through the working area by one or more actuators, the mesh mesh 156 is maintained under tension (e.g., lateral strain relative to the plane of the mesh) 160. In some cases, the mesh transport and tensioning mechanism can be configured to operate in both forward and reverse directions.

[0066] Figure 7 An example of printing dot material from a film substrate using a laser jet release system 170 according to some embodiments of the present invention is shown. In this embodiment, a laser 172 is used to generate droplets 174 of a high viscosity material, which, when solidified in an aggregate, form 2D and / or 3D structures on a receiving substrate (not shown in this view). In this technique, a substantially regular pattern (e.g., dots 176) of a viscous material is printed or otherwise applied to a transparent substrate 178 (e.g., the intermediate substrate 36 above) and then brought to a work area. The laser 172 is used to heat the interface between the transparent substrate 178 and the material 176, causing the droplets 174 to be ejected. The substrate 178 is transparent at least at the laser wavelength of interest, and the heating of the laser 172 causes the droplets 174 to be ejected toward a receiver (not shown in this view). As the substrate 178 is conveyed through the work area by one or more actuators, the substrate 178 is held under tension (e.g., lateral strain relative to the plane of the screen). In some cases, the tensioning mechanism can be configured to operate in both forward and reverse directions. The material may be printed or applied to substrate 178 as dots 176 or as a layer in any other shape or form.

[0067] Figure 8 An aspect of imaging a point on a solid or film substrate using a primary laser channel according to some embodiments of the present invention is shown. In this example, a point 192 of material has been printed on a solid substrate 194 (e.g., a final substrate 38 such as a PC board), and a camera 196 is used to image the point via the primary laser channel. Alternatively, the camera 196 can be offset from the primary laser channel and a semi-transparent mirror 198 inserted therein to reflect the image of the point 192 toward the camera. Such imaging can be used to ensure that the point of material is optimally placed on the final substrate. The same imaging system can be used to monitor the material on the final substrate from the top and / or the side.

[0068] The above discussion has primarily been directed to systems and methods for printing highly viscous materials at high resolution onto substrates at very high speeds. However, the same systems and methods can be used for stamp production or for printing multiple materials in the same layer. For example, Fig. 9Various aspects of stamp manufacturing made by such a system are shown. In a first stage 200, a shaped layer 202 of UV curable material (not necessarily a dot matrix) is printed onto an intermediate substrate 204. This layer is then exposed to UV source light and cured to form a cured layer 206. Thereafter, the intermediate substrate with the cured material layer is returned to the first printing unit, and a second (or additional) layer 208 of material is dispensed on the coated substrate and printed at the first printing unit. This second / additional layer is then exposed to a UV light source to produce a second / additional cured layer of material 210. Multiple layers of the same or different materials can be printed onto the intermediate substrate in this manner.

[0069] Fig.10 The aspect of printing multiple materials in the same layer is illustrated. One or more portions of a first material 212 are printed on a film substrate 214 in the manner described above, but then the intermediate substrate is returned to the first printing unit and a second (or multiple) portions 216 of a different material are dispensed onto the coated substrate to form a uniform layer. Using this approach, multiple materials can be printed onto the final substrate simultaneously.

[0070] An example of printing multiple materials from an intermediate substrate to a final substrate is adhesive printing. In this case, a mixture of two materials can trigger a reaction between the materials (for example in the case of epoxy-amine or in the case of silanol-Pt catalysts). The materials are not mixed on the intermediate substrate, but only printed once on the final substrate. By doing this, clogging and other undesirable side effects are avoided, and mixing occurs only at the desired location.

[0071] Thus, in various embodiments, systems and methods for printing viscous materials (e.g., solder paste) have been described that employ a multi-step process in which the viscous material is dispensed onto a donor substrate, then printed onto an intermediate substrate, and ultimately transferred to a final substrate via a second printing process or a direct application process. Throughout the various steps of the printing process, the material may undergo one or more steps of a curing, drying system, and / or imaging system. In order to obtain a very narrow dot size distribution when printing onto an intermediate substrate, it is important to have a very well defined distance control between the coated donor substrate and the intermediate substrate. To this end, any of a variety of mechanical solutions may be used. For example, the distance between the coated donor substrate (which may be a film or foil) and the intermediate film may be deterministically defined by having both located on the same mechanical component. Alternatively, the distance may be controlled by using a mechanical, well-defined foil or two rollers adjacent to each other. Further, the distance may be controlled by using a set of three actuators at the corners of the support unit that allow translation and rotation on each substrate and conjugate the two into a unit.

[0072] To enhance jetting position and resolution during printing, an imaging system can be added to monitor the size and position of the printed dots on the intermediate substrate and the final substrate. To this end, one or more imaging systems can be added for monitoring the intermediate substrate and for monitoring the final substrate. The imaging system for the intermediate substrate can use a CCD, microscope or 3D microscope and computer software to monitor the dot size on the plane of the intermediate substrate at an angle perpendicular to the plane of the intermediate substrate. Monitoring can also be performed before and / or after the second printing unit responsible for transferring the material to the final substrate. The same imaging system can be used to monitor the material on the final substrate from the top and / or side. Different imaging solutions are designed to increase installation success rates and reduce the need for rework, creating highly reliable and repeatable results.

[0073] Although not shown in detail, it should be understood that the various components of the printing system described herein operate under the control of one or more controllers, which are preferably processor-based controllers that operate under the direction of machine-executable instructions stored on a tangible machine-readable medium. Such a controller may include a microprocessor and a memory that are communicatively coupled to each other via a bus or other communication mechanism for communicating information. The memory may include a program storage memory, such as a read-only memory (ROM) or other static storage device, and a volatile memory, such as a random access memory (RAM) or other dynamic storage device, and each may be coupled to the bus to provide and store information and instructions to be executed by the microprocessor. The volatile memory may also be used to store temporary variables or other intermediate information during the execution of instructions by the microprocessor. Alternatively or additionally, a storage device such as a solid-state memory, a magnetic disk, or an optical disk may be provided and coupled to the bus to store information and instructions. The controller may also include a display for displaying information to a user, and various input devices, including an alphanumeric keyboard and a cursor control device, such as a mouse and / or a touch pad, as part of a user interface for the printing system. In addition, one or more communication interfaces may be included to provide two-way data communication to and from the printing system. For example, a network interface including a wired and / or wireless modem may be used to provide such communications.

[0074] In various embodiments, the present invention provides:

[0075] 1. A system and method capable of printing a viscous material at high resolution and high speed, comprising two printing units and an intermediate substrate that transfers the viscous material between the two printing units.

[0076] 2. A system or method comprising: a first printing unit, which is optionally combined with a coating unit and prints material on an intermediate substrate; and a second printing unit, which receives the intermediate substrate and prints material from the intermediate substrate onto a final substrate.

[0077] 3. The system or method of embodiment 2, wherein the first printing unit comprises an optional coating system configured to form a uniform layer of material on the donor substrate.

[0078] 4. The system or method of embodiment 2 or 3, wherein the donor substrate is a flexible substrate.

[0079] 5. A system or method as described in any of embodiments 2 to 4, wherein the coating system includes: (a) an injector of material and an air pump or mechanical pump to drive the material onto the donor substrate, and transport the donor substrate together toward and through a well-defined gap between rollers or knives to form a uniform material layer, the uniform material layer having a thickness defined by the gap; (b) a screen printing module, the screen printing module is configured to coat a screen or film plate with a film having well-defined holes with the material, and transfer the material to the donor substrate in soft or hard contact with a blade or scraper; (c) a dispenser or inkjet head to print the material onto the donor substrate; (d) a gravure printing or micro-gravure printing system to coat the donor substrate with a highly uniform material layer; (e) a slot die system to coat the donor substrate with a highly uniform material layer; or (f) a roller coating system to coat the donor substrate with a highly uniform layer.

[0080] 6. The system or method of any one of embodiments 2 to 5, wherein the coating system is contained within a closed chamber with a controlled environment to extend the pot life of the material.

[0081] 7. A system or method as described in any of embodiments 2 to 6, wherein the coating system contains more than one material, thereby creating the possibility of printing multiple materials onto an intermediate substrate in a controlled sequence and making it possible to print more than one material on the final substrate.

[0082] 8. A system or method as described in any of embodiments 2 to 7, wherein the intermediate substrate is bidirectionally translated through the coating system in a controlled manner, for example by opening a gap between coating rollers, thereby allowing the same area of ​​the intermediate substrate to be re-coated with material without contaminating the coating rollers to reduce waste.

[0083] 9. A system or method as described in any of embodiments 2 to 8, wherein the material is: (a) solder paste or other metal paste for printed electronic devices; (b) metal paste or ceramic paste; (c) high viscosity material; (d) wax material; (e) polymer material or a mixture of polymer and monomer materials; (f) sensitive low viscosity material; (g) material that can be cured by ultraviolet light or heat; and / or (h) dry material.

[0084] 10. A system or method as described in any of embodiments 2 to 9, wherein the first printing unit is: (a) a laser-based system comprising a high-frequency laser to enable the material to be ejected from the donor substrate to the intermediate substrate; (b) an inkjet head system configured to eject the material directly onto the intermediate substrate; (c) a dispenser head system to print the material directly onto the intermediate substrate; (d) an offset printer module, a gravure printing module, or other printing module for printing the material directly onto the intermediate substrate; or (e) a screen printing module, wherein the material is coated on a screen or a stencil having a film with well-defined holes and transferred to the intermediate substrate.

[0085] 11. A system or method as described in any of embodiments 2 to 10, wherein the first printing unit is a laser-assisted deposition / laser dispensing system, which is rotated 0-90 degrees or 90-180 degrees from the main axis of the gravitational field in which it is located.

[0086] 12. A system or method as described in any of embodiments 2 to 11, wherein a blade or a squeegee is used to transfer the material to the intermediate substrate with soft or hard bonding, thereby producing a dot array directly on the intermediate substrate.

[0087] 13. The system or method of any one of embodiments 2 to 11, wherein the first printing unit comprises a gap control unit configured to maintain a well-defined gap between the donor substrate and the intermediate substrate.

[0088] 14. A system or method as described in any of embodiments 2 to 13, wherein the gap control unit includes: (a) a plane of three actuators that allows translation and rotation; (b) a plane of three actuators at the corners of the donor substrate and the intermediate substrate that allows translation and rotation of both the donor substrate and the intermediate substrate; (c) a fixed support member below the intermediate substrate; or (d) a transparent solid substrate as an intermediate substrate.

[0089] 15. The system or method of any one of embodiments 2 to 14, wherein the planes of the donor substrate and the intermediate substrate are independent of or riding on each other.

[0090] 16. A system or method as described in any of embodiments 2 to 15, wherein the intermediate substrate is: (a) a continuous transparent film substrate; (b) a transparent film substrate coated with a metal layer or a metal and a dielectric layer; (c) a transparent solid substrate; (e) a continuous film substrate that can transport the material printed on the first printing unit to the second printing unit by rolling; or (f) a transparent solid substrate that can transport the material printed on the first printing unit to the second printing unit by a robotic arm, with optional changes in direction.

[0091] 17. The system or method of any one of embodiments 2 to 16, wherein the intermediate substrate after printing at the first printing unit is moved toward the second printing unit by a motor.

[0092] 18. A system or method as described in any of embodiments 2 to 17, wherein during the process of moving the intermediate substrate from the first printing unit to the second printing unit, the material is cured by UV light or dried by a heater and / or processed by an imaging system.

[0093] 18. A system or method as described in any of embodiments 2 to 18, wherein the imaging system is: (a) a microscope or CCD that photographs printed dots of material on an intermediate substrate and measures the dots in two dimensions; (b) a 3D microscope that photographs printed dots of material on an intermediate substrate and measures the dots in three dimensions; or (c) two microscopes or CCDs arranged so that one can be used to photograph printed dots of material on an intermediate substrate and measure the dots in two dimensions, while the other can be used to measure the dots in a direction orthogonal to the two dimensions.

[0094] 19. The system or method of any one of embodiments 2 to 18, wherein data collected by the imaging system is transferred to a second printing unit to precisely deposit dots of material onto a final substrate.

[0095] 20. The system or method of any one of embodiments 2 to 19, wherein the imaging system includes components located before and / or after the second printing unit along the travel path of the material on the intermediate substrate.

[0096] 21. The system or method of any one of embodiments 2 to 20, wherein the imaging system is configured to image an intermediate substrate, a final substrate, or both.

[0097] 22. A system or method as described in any of embodiments 2 to 21, wherein at least a portion of the imaging system located at the second printing unit includes a mirror arranged to allow imaging of the surface of the intermediate substrate, or by simultaneously imaging the size of the material dot and the target area of ​​the final substrate using the main laser channel of the second printing unit.

[0098] 23. A system or method as described in any of embodiments 2 to 22, wherein the second printing unit is: (a) a laser-based system comprising a high-frequency laser that enables material dots to be ejected from an intermediate substrate to a final substrate; (b) a laser release system; (c) a laser release system with a 2D array scanning laser; (d) a laser release system in which the system is rotated 0-90 degrees or 90-180 degrees from the main axis of the gravitational field in which it is located; and / or (e) a deposition position where the intermediate substrate is directly engaged with the final substrate.

[0099] 24. The system or method of any one of embodiments 2 to 23, wherein after printing the material onto the final substrate in the second printing unit, the printed final substrate is cured by UV light or dried by a heater.

[0100] 25. A system or method as described in any of embodiments 2 to 23, wherein after printing the material onto the intermediate substrate in the first printing unit, the printed intermediate substrate is cured by UV light or the printed intermediate substrate is dried by a heater, and the intermediate substrate is returned to the first printing unit for printing a second (or additional) layer of a second material that may be different from the first material.

Claims

1. A system (20a, 20b, 60, 92, 110, 120) comprising a first printing unit (32) and a second printing unit (44), wherein the first printing unit (32) is configured to print individual dots (40) of a material (62) on an intermediate substrate (36), and the second printing unit (44) is configured to receive the intermediate substrate (36) having the dots (40) of the material (62) printed thereon, and transfer the dots (40) of the material (62) from the intermediate substrate (36) to a final substrate (38), wherein the first printing unit (32) comprises a coating system (22) configured to form a uniform layer (26) of the material (62) on a donor substrate (28), the first printing unit (32) being configured to transfer the material as individual dots from the donor substrate (28) to the intermediate substrate (36) across a donor substrate-to-intermediate substrate gap between the donor substrate (28) and the intermediate substrate (36), the second printing unit (44) being configured to transfer the dots of material printed on the intermediate substrate (36) from the intermediate substrate (36) to the final substrate across an intermediate substrate-to-final substrate gap between the intermediate substrate (36) and the final substrate (38), and the intermediate substrate-to-final substrate gap being wider than the donor substrate-to-intermediate substrate gap, and The coating system (22) comprises: The coating system (22) includes an injector (64) of the material (62) and an air pump or a mechanical pump arranged to drive the material onto the donor substrate (28), and the coating system (22) is also configured to transport the donor substrate (28) with the material (62) thereon toward and through the gap (70) between rollers or knives (72) to form the uniform layer (26) of the material (62) on the donor substrate (28), and the uniform layer (26) of the material (62) has a thickness defined by the gap (70).

2. The system (20a, 20b, 60, 92, 110, 120) of claim 1, wherein the coating system (22) is enclosed in a controlled environment (34).

3. The system (20a, 20b, 60, 92, 110, 120) of any of the preceding claims, wherein the coating system (22) is configured to apply more than one material to the donor substrate (28) in a variety of printing procedures.

4. The system (20a, 20b, 60, 92, 110, 120) of claim 1, wherein the material (62) comprises: Solder paste or other metal paste for printed electronic devices, metal paste, ceramic paste, high viscosity material, wax material, polymer material or mixture of polymer and monomer material, sensitive low viscosity material, material curable by ultraviolet (UV) or heat, or dryable material.

5. The system (20a, 20b, 60, 92, 110, 120) of claim 1, wherein one or both of the first printing unit (32) and / or the second printing unit (44) comprises a laser-based system comprising a high-frequency laser configured to eject the dots (40) of the material (62) from one substrate to another substrate.

6. The system (20a, 20b, 60, 92, 110, 120) of claim 1, wherein the intermediate substrate (36) is a continuous film substrate, and the system (20a, 20b, 60, 92, 110, 120) includes rollers to transport the dots (40) of the material (62) printed on the intermediate substrate (36) on the first printing unit (32) to the second printing unit (44).

7. The system (20a, 20b, 60, 92, 110, 120) of claim 1, wherein the intermediate substrate (36) is a transparent solid substrate (124), and the system (20a, 20b, 60, 92, 110, 120) includes a robot to transport the dots (40) of the material (62) printed on the intermediate substrate (36) on the first printing unit (32) to the second printing unit (44).

8. The system (20a, 20b, 60, 92, 110, 120) of claim 1 further comprises a UV curing system and / or a drying system (116), wherein the UV curing system and / or the drying system is configured to: (i) cure the dots (40) of the material (62) printed on the intermediate substrate (36) while the intermediate substrate (36) moves from the first printing unit (32) to the second printing unit (44); (ii) cure the final substrate (38) after the dots (40) of the material (62) have been transferred to the final substrate (38); or (iii) both of the above.

9. The system (20a, 20b, 60, 92, 110, 120) of claim 1 further comprising one or more imaging systems (50), wherein the one or more imaging systems are configured to: (i) image the dots (40) of the material (62) printed on the intermediate substrate (36) during movement of the intermediate substrate (36) from the first printing unit (32) to the second printing unit (44); (ii) image the dots (40) of the material (62) after the dots (40) of the material (62) have been transferred to the final substrate (38); or (iii) both of the above.

10. The system (20a, 20b, 60, 92, 110, 120) of claim 9, wherein at least one of the one or more imaging systems (50) is configured to (i) measure the dots (40) of the material (62) printed on the intermediate substrate (36) in two or three dimensions as the intermediate substrate (36) moves from the first printing unit (32) to the second printing unit (44), and (ii) transfer data collected by the measurement to the second printing unit (44) for transfer of the dots (40) of the material (62) to the final substrate (38).

11. A method comprising: printing individual dots (40) of material (62) onto the intermediate substrate (36) by a first printing unit (32); and transferring the dots (40) of the material (62) printed on the intermediate substrate (36) to a final substrate (38) by a second printing unit (44), the second printing unit (44) being configured to receive the intermediate substrate (36) on which the dots (40) of the material (62) are printed, wherein the first printing unit (32) includes a coating system (22) configured to form a uniform layer (26) of the material (62) on a donor substrate (28), the first printing unit (32) transferring the material as individual dots from the donor substrate (28) to the intermediate substrate (36) across a donor substrate-to-intermediate substrate gap between the donor substrate (28) and the intermediate substrate (36), the second printing unit (44) transferring the dots of material printed on the intermediate substrate (36) from the intermediate substrate (36) to the final substrate across an intermediate substrate-to-final substrate gap between the intermediate substrate (36) and the final substrate (38), and the intermediate substrate-to-final substrate gap is wider than the donor substrate-to-intermediate substrate gap, and The coating system (22) comprises: The coating system (22) includes an injector (64) of the material (62) and an air pump or a mechanical pump arranged to drive the material onto the donor substrate (28), and the coating system (22) is also configured to transport the donor substrate (28) with the material (62) thereon toward and through the gap (70) between rollers or knives (72) to form the uniform layer (26) of the material (62) on the donor substrate (28), and the uniform layer (26) of the material (62) has a thickness defined by the gap (70).

12. The method of claim 11, wherein the coating system (22) applies more than one material to the donor substrate (28) in a plurality of printing procedures.

13. A method as claimed in claim 11 or 12, wherein the dots (40) of the material (62) printed on the intermediate substrate (36), the final substrate (38) after transferring the dots (40) of the material (62) thereto, or both: (i) cured using ultraviolet (UV) light and / or heat; (ii) imaged using one or more imaging systems (50); or (iii) both of the above.

Images