Apparatus and method for printing a viscous substance, by means of laser induced forward transfer, on a product

Abstract

An apparatus and method for printing a viscous substance, by means of Laser Induced Forward Transfer, on a product, the apparatus comprising: - a substrate handler having a shaft comprising a substrate carrier, the substrate carrier being arranged for holding a substrate or a further substrate; - a coater configured for providing a layer of the viscous substance on a first surface of the respective substrate in a coating position of the respective substrate; - a printing device configured for transmitting a beam of electromagnetic radiation for printing the viscous substance, by means of Laser Induced Forward Transfer, on a predetermined position of the product in a printing position of the respective substrate; and - a docking arrangement comprising at least two docking stations, the docking arrangement being configured for decoupling the respective substrate from the substrate carrier and docking the respective substrate to the respective docking station; wherein the substrate handler is configured for moving the respective substrate between the coater and the printing device by moving the respective substrate in a virtual plane, defined by a longitudinal direction and a width direction and oriented perpendicular to a height direction, and about a first pivoting axis in the virtual plane for bringing the respective substrate from the coater to the printing device, wherein the at least two docking stations are each configured for providing the respective substrate into the respective coating position or printing position.

Description

[0001] Title: Apparatus and method for printing a viscous substance, by means of Laser Induced Forward Transfer, on a product

[0002] Description:

[0003] According to a first aspect of the present disclosure, the disclosure relates to an apparatus for printing a viscous substance, by means of Laser Induced Forward Transfer, on a product.

[0004] According to a second aspect of the present disclosure, the disclosure relates to a method for printing a viscous substance, by means of Laser Induced Forward Transfer, on a product.

[0005] A known method for applying a viscous substance such as solder paste to a product, such as a Printed Circuit Board (PCB), relies on stencil printing or dispensing. Stencil printing is a deposition method requiring direct contact with the PCB. Stencil printing is a non-digital method, where a stencil, also referred to as a mask, is used to define the printing pattern. It also limits the freedom to achieve small volumes for small components while allowing relatively large volumes of viscous substance to be applied for the larger components which are also still present on new PCBs.

[0006] Dispensing is a nozzle-based deposition technology requiring the control of a gap that is present between the end of the nozzle and the PCB. The gap between the end of the nozzle and the PCB is either actively measured and compensated or calibrated according to a pre-mapping. A drawback of dispensing is the relative low speed of applying the viscous substance. It is noted that a relative high speed of applying viscous substance is in particular relevant for high volume production. A further drawback of dispensing is the relative frequent clogging of nozzles of the dispenser resulting in missed shots, thereby avoiding, or at least partly avoiding, application of viscous substance onto the PCB.

[0007] A further method for applying a viscous substance on a product, such as solder interconnects in a three-dimensional Integrated Circuit (IC), also referred to as 3D interconnects, 3D chip stacking, 3D stacking or 3D packaging may comprise placing preformed solder balls in deposits of a Ball Grid Array (BGA) socket. A drawback of this placement technique is the relatively expensive equipment required. In addition, the size of the solder balls that may be placed is relatively large.

[0008] Furthermore, increasing the throughput, thus the processing speed of printing the viscous substance on products, may have a negative impact on the printing quality and thus, on the quality of the resulting products.

[0009] It is an object of the present disclosure to provide an apparatus and a method that at least partly overcomes a drawback of the known methods of applying a viscous substance to a product.

[0010] The apparatus according to the first aspect of the present disclosure comprises: a substrate handler having a shaft comprising a substrate carrier, the substrate carrier being arranged for holding a substrate or a further substrate; a coater configured for providing a layer of the viscous substance on a first surface of the respective substrate in a coating position of the respective substrate; a printing device configured for transmitting a beam of electromagnetic radiation for printing the viscous substance, by means of Laser Induced Forward Transfer (LIFT), on a predetermined position of the product in a printing position of the respective substrate; and a docking arrangement comprising at least two docking stations, the docking arrangement being configured for decoupling the respective substrate from the substrate carrier and docking the respective substrate to the respective docking station; wherein the substrate handler is configured for moving the respective substrate between the coater and the printing device by moving the respective substrate in a virtual plane, defined by a longitudinal direction and a width direction and oriented perpendicular to a height direction, and about a first pivoting axis in the virtual plane for bringing the respective substrate from the coater to the printing device, wherein the at least two docking stations are each configured for providing the respective substrate into the respective coating position or printing position. Laser Induced Forward Transfer (LIFT) is a direct-write technique that was first reported by Bohandy, Kim, and Adrian in 1986 for the deposition of Cu patterns on Si and fused silica substrates under high vacuum conditions. In this technique, a pulsed laser is used to induce the transfer of the material from a donor substrate to a receiver substrate, usually placed at a short distance or in contact with each other. Donor substrates are usually laser transparent and coated with a thin film of the material of interest. As the laser beam passes through the transparent substrate, it is being absorbed by the film, which is subsequently propelled toward the receiver substrate, above a certain laser energy threshold.

[0011] One of the requirements in the LIFT printing of viscous substance on products, is that the coating of the respective substrate’s first surface needs to be done when the first surface of the substrate is facing upwards. Another requirement is that the LIFT printing is done by having the coated first surface of the respective substrate facing downwards towards the product. By being able to position the first surface of the respective substrate into the coating position and the first surface of the respective substrate in the printing position by moving the respective substrate about a first pivoting axis, it becomes much more practical to coat the first surface of the respective substrate and subsequently, print the viscous substance - as coated on the first surface of the respective substrate - on the product.

[0012] The substrate handler is configured for controlling the coarse movements of the substrate between the coater and the printing device, which is considered a relatively large distance, while the docking arrangement is configured for controlling the fine and precise moving of the substrate into the coating position or into the printing position, which is considered a relatively small distance. The apparatus according to the first aspect of the present disclosure enables these two types of movement steps in the printing of the viscous substance on the product to work properly with each other.

[0013] With the apparatus according to the first aspect of the present disclosure, docking the substrate becomes easier and provides improved printing results. With “docking” is meant that the substrate is placed in a fixed position relative to the product, e.g., the PCB, at 1) the coater such that coating of the first surface of the substrate can be done in a controlled manner, and 2) at the printing device such that printing the selective layer-part of the viscous substance onto the predetermined location of the product can done in a controlled manner at a precise gap distance from the product. The docking needs to be done with high precision. Moving the substrate over a distance with the same high precision would be nearly impossible, and therefore, the substrate handler of the apparatus according to the first aspect of the present disclosure is a solution for reassuring the high precision locking of the substrate.

[0014] The coating position is the position in which the first surface of the respective substrate or further substrate is facing upwards in the height direction, i.e. , facing away from the product along the z-axis.

[0015] The printing position is the position in which the first surface of the respective substrate or further substrate is facing downwards in the height direction, i.e., facing towards the product along the z-axis.

[0016] The coating step is considered a relatively “dirty” step and is preferably done at a location within the apparatus that is easily accessible for the operator while keeping the printing area, which contains mirrors, optics and scanner that are preferred not to be touched or contaminated, at a safe distance by being positioned deeper within the apparatus. Hence, the apparatus according to the first aspect of the present disclosure allows such a layout of the components within the apparatus so that separating the relatively “dirty” coating process is at a safe distance from the clean printing area.

[0017] The at least two docking stations are not only each configured for providing the respective substrate into the respective coating position or printing position, but also for maintaining the respective substrate in said respective position.

[0018] The printing device may comprise an emitter unit that is used for transmitting the beam of electromagnetic radiation for the printing of the viscous substance on the product. Furthermore, the electromagnetic radiation can for example be a laser beam. Moving of the respective substrate in the virtual plane includes pivoting about a second pivoting axis, wherein the second pivoting axis is extending in the height direction perpendicular to the virtual plane.

[0019] In an embodiment, the substrate handler comprises a plurality of the substrate carriers, wherein the plurality of substrate carriers are mutually equally spaced with respect to each other (i.e., mutually equally spaced in the virtual plane as defined above), such as a diametric position, and preferably wherein the substrate handler is configured for moving, preferably simultaneously, the other of the substrate and the further substrate between the printing device and the coater for bringing the other of the substrate and the further substrate from the printing device to the coater for simultaneously coating and printing. Thus, for example, the substrate handler can move the substrate from the coater to the printing device and simultaneously the further substrate from the printing device to the coater, or vice versa. Providing the apparatus with a substrate handler being able to hold and move two or even more substrates simultaneously between different positions allows coating and printing at the same time and this reduces the cycle time such that a higher throughput may be achieved.

[0020] Furthermore, the substrate handler is further configured for bringing the respective substrate from the printing device to the coater.

[0021] In an embodiment, apparatus further comprises a support for positioning the product in relation to the first surface of the respective substrate in the respective coating position or printing position of the respective substrate.

[0022] In another embodiment, the apparatus further comprises a scanning device arranged for scanning the beam of electromagnetic radiation across the first surface of the respective substrate for printing a selective layer-part of the viscous substance.

[0023] In yet another embodiment, the substrate handler further comprises a displacement arrangement for moving the respective substrate between an upper position and a lower position in the height direction. Preferably, the displacement arrangement comprises a constant-velocity joint adapted for allowing the displacement arrangement to rotate freely with respect to the shaft and for compensating for an angle between the displacement arrangement and the shaft.

[0024] The displacement arrangement relates to the pre-docking of the substrate. Between moving the substrate, by the substrate carrier, provided by the substrate handler, from the coater to the printing device, or vice versa, and docking the respective substrate to the respective docking station for providing the respective substrate in the respective coating position or printing position, the displacement arrangement moves the respective substrate from the upper position to the lower position in the height direction, or vice versa.

[0025] Moving the substrate between the coater and the printing device and moving the substrate between the upper position and the lower position are considered relatively coarse movements, whereas docking the substrate into the coating position or into the printing position is considered a fine and precise movement.

[0026] The substrate handler may comprise an actuator or at least two circular toothed wheels arranged for pivoting the respective substrate about the first pivoting axis in the virtual plane and optionally about a second pivoting axis in the height direction.

[0027] In an embodiment, the respective substrate is substantially transparent, preferably transparent, for the beam of electromagnetic radiation.

[0028] The method according to the second aspect of the present disclosure comprises the steps of: providing a substrate or a further substrate, and a product; supporting the product; holding, by a substrate carrier comprised by a substrate handler, the respective substrate; moving, by the substrate handler, the respective substrate to a coater by moving the respective substrate in a virtual plane, defined by a longitudinal direction and a width direction and oriented perpendicular to a height direction, and about a first pivoting axis in the virtual plane; providing, by a docking station of at least two docking stations provided in a docking arrangement, a first surface of the respective substrate into a coating position; providing a layer of the viscous substance on the first surface of the respective substrate; moving, by the substrate handler, the respective substrate to a printing device by moving the respective substrate in the virtual plane and about the first pivoting axis in the virtual plane; providing, by the docking station of the least two docking stations, the first surface of the respective substrate into a printing position; emitting a beam of electromagnetic radiation for printing the viscous substance, by means of Laser Induced Forward Transfer (LIFT), on a predetermined position of the product.

[0029] The skilled person will understand that the order of execution of the steps of the method according to the second aspect of the present disclosure may be different as compared to the order as presented in the claims. Hence, the method steps may be executed in different manners.

[0030] In an embodiment of the method according to the second aspect of the present disclosure, the substrate and the further substrate are provided during the step of providing, and wherein, during the step of moving the respective substrate to the coater, the other of the substrate and the further substrate is moved, preferably simultaneously, to the printing device by moving the other of the substrate and the further substrate in the virtual plane and about the first pivoting axis in the virtual plane, and, during the step of moving the respective substrate to the printing device, the other of the substrate and the further substrate is moved, preferably simultaneously, to the coater in the virtual plane and about the first pivoting axis in the virtual plane.

[0031] In another embodiment of the method according to the second aspect of the present disclosure, the substrate and the further substrate are provided during the step of providing, and wherein, during the step of providing the first surface of the respective substrate in the coating position, the first surface of the other of the substrate and the further substrate is provided in the printing position, and, during the step of providing the first surface of the respective substrate in the printing position, the first surface of the other of the substrate and the further substrate is provided in the coating position.

[0032] The method may further comprise the step of: scanning the beam of electromagnetic radiation across the first surface of the respective substrate for printing a selective layer-part of the viscous substance, by means of Laser Induced Forward Transfer (LIFT).

[0033] The method may also comprise the step of: moving the respective substrate between an upper position and a lower position in the height direction.

[0034] Preferably, the step of moving the respective substrate between the upper position and the lower position is performed simultaneously with the step of moving the respective substrate to the coater and / or simultaneously with the step of moving the respective substrate to the printing device.

[0035] In an embodiment of the method according to the second aspect of the present disclosure, one or more of the steps of moving the respective substrate to the coater, providing the first surface of the respective substrate in the coating position, providing the layer of viscous substance, moving the respective substrate to the printing device, providing the first surface of the respective substrate to the printing position, and emitting, and optionally scanning the beam of electromagnetic radiation and moving the respective substrate between the upper position and the lower position, are repeated for providing the viscous substance to predetermined positions of the product.

[0036] In another embodiment of the method according to the second aspect of the present disclosure, the respective substrate is substantially transparent, preferably transparent, for the beam of electromagnetic radiation emitted during the step of emitting.

[0037] In an embodiment of the method according to the second aspect of the present disclosure, the selective layer-part of the viscous substance is heated to a temperature in the range of 25 °C to 70 °C, preferably in the range of 30 °C to 50 °C, more preferably in the range of 30 °C to 40 °C.

[0038] The viscous substance may comprise solder paste or conductive glue, preferably consists of a solder paste or a conductive glue, and wherein, during the step of heating, by the heating device, the viscosity of the viscous substance is in the range of 0.5 to 200 Pa s (500 to 200.000 cP).

[0039] In this regard, the viscosity of the viscous substance, such as solder paste, may be determined according to the IPC-TM-650-2.4.34.1 Test Methods Manual and IPC- TM-650-2.4.34.3 Test Methods Manual depending on the viscosity of the solder paste.

[0040] Preferably, the method according to the second aspect of the present disclosure uses the apparatus according to the first aspect of the present disclosure.

[0041] Embodiments of the apparatus for printing a viscous substance on a product according to the first aspect of the present disclosure as presented herein are also applicable to the method for printing a viscous substance on a product according to the second aspect of the present disclosure, and vice versa.

[0042] Effects of the apparatus for printing a viscous substance on a product according to the first aspect of the present disclosure as presented herein correspond to or are similar to effects of the method for printing a viscous substance on a product according to the second aspect of the present disclosure.

[0043] The present disclosure is hereinafter explained in more detail with reference to the accompanying drawings in which embodiments of the present disclosure are shown and in which like reference numbers indicate the same or similar elements. The present disclosure is by no means limited to the embodiments described therein.

[0044] Fig. 1 schematically shows a top view of an apparatus according to the present disclosure;

[0045] Fig. 2 schematically shows an isometric side view of the apparatus of Fig. 1 ;

[0046] Fig. 3 schematically shows an isometric side view of the apparatus of Fig. 1 ;

[0047] Fig. 4 schematically shows an isometric view of the substrate handler;

[0048] Fig. 5 schematically shows part of the substrate handler shown from a different side;

[0049] Fig. 6 schematically shows a top view of a constant-velocity joint;

[0050] Fig. 7 schematically shows a side view of a constant-velocity joint;

[0051] Fig. 8 schematically shows printing of the viscous substance on a product; Fig. 9 schematically shows a method according to the present disclosure.

[0052] In Fig. 1 , an apparatus 1 according to the present disclosure for printing a viscous substance 3 on a product 5 is shown. The apparatus 1 comprises a substrate handler 7 having a shaft 9 comprising a substrate carrier 11 , the substrate carrier 11 being arranged for holding a substrate 13a or a further substrate 13b.

[0053] Furthermore, in Fig. 1 , the apparatus 1 comprises a coater 15 configured for providing a layer 17 of viscous substance 3 on the first surface 19 of the respective substrate 13a, 13b in the coating position 21 of the respective substrate 13a, 13b; a printing device 23 configured for transmitting a beam of electromagnetic radiation 27 for printing the viscous substance 3, by means of Laser Induced Forward Transfer (LIFT), on a predetermined position of the product 5 in a printing position 29 of the respective substrate 13a, 13b; and a docking arrangement 43.

[0054] The apparatus 1 also comprises a support 31 for positioning the product 5 in relation to the first surface 19 of the respective substrate 13a, 13b in the respective coating position 21 or printing position 29 of the respective substrate 13a, 13b. In the shown top view of the apparatus 1 , the product 5, seen from an operator’s 51 position, moves from left to right as indicated by the black arrows. The apparatus 1 of Fig. 1 further comprises a scanning device 33 arranged for scanning the beam of electromagnetic radiation 27 across the first surface 19 of the respective substrate 13a, 13b for printing a selective layer-part 37 of the viscous substance 3.

[0055] Fig. 2 shows an isometric side view of the apparatus 1 of Fig. 1 from the side facing towards the operator 51 (not shown in Fig. 2). This side view provides more details about how the apparatus 1 according to the present disclosure may be arranged.

[0056] Fig. 3 shows an isometric side view of the apparatus 1 of Fig. 1 from the side facing away from the operator 51 (not shown in Fig. 3). From this side the control unit 53 can be seen. The control unit 53 is communicatively coupled with the substrate handler 7 and the support 31 . The scanning device 33 is also clearly visible in this side view.

[0057] A schematic example of the substrate handler 7 is shown in Fig. 4. The substrate handler 7 is configured for moving the respective substrate 13a, 13b between the coater 15 and the printing device 23 by moving the respective substrate 13a, 13b in a virtual plane v and about a first pivoting axis p1 in the virtual plane v for bringing the respective substrate 13a, 13b from the coater 15 to the printing device 23. The virtual plane v is defined by a longitudinal direction x and a width direction y and is oriented perpendicular to a height direction z, as shown in Fig. 1.

[0058] The moving of the substrate 13a about the first pivoting axis p1 is shown in Fig. 5.

[0059] The substrate handler 7 in Fig. 4 comprises two substrate carriers 11 (though it can comprise more than two). The substrate carriers 11 are mutually equally spaced with respect to each other. In the shown example, the two substrate carriers 11 are diametrically positioned. The substrate handler 7 is configured for moving the substrate 13a with one substrate carrier 11 from the coater 15 to the printing device 23 and simultaneously the further substrate 13b with the other substrate carrier 11 from the printing device 23 to the coater 15, or vice versa, for simultaneously coating and printing. The substrate handler 7 is thus also configured for bringing the substrate 13a from the printing device 23 to the coater and simultaneously the further substrate 13b from the coater 15 to the printing device 23.

[0060] Fig. 4 further shows that the substrate handler 7 further comprises a displacement arrangement 39. The displacement arrangement 39 is for moving the respective substrate 13a, 13b between an upper position and a lower position in the height direction z. In Fig. 4, the substrate 13a moves towards to lower position and simultaneously, the further substrate 13b moves towards the upper position.

[0061] Furthermore, the substrate handler 7 comprises an actuator (which may also be at least two circular toothed wheels) arranged for pivoting the respective substrate 13a, 13b about the first pivoting axis p1 in the virtual plane v and in the example shown in Figs. 4 and 5, also about a second pivoting axis p2 in the height direction z.

[0062] The displacement arrangement 39, shown from the top in Fig. 6 (a) and from a side in Fig. 6 (b), comprises a constant-velocity joint 41 that is adapted for allowing the displacement arrangement 39 rotate freely with respect to the shaft 9 and for compensating an angle a1 ,a2 between the displacement arrangement 39 and the shaft 9.

[0063] Fig. 7 shows a schematic representation of the docking arrangement 43, which comprises two docking stations 45a, 45b. The docking arrangement 43 is configured for decoupling the respective substrate 13a, 13b from the substrate carrier 11 and docking the respective substrate 13a, 13b to the respective docking station 45a, 45b. The two docking stations 45a, 45b are each configured for providing the respective substrate 13a, 13b into the respective coating position 21 or printing position 29.

[0064] Fig. 8 (a)-(d) shows a schematic of the printing of a viscous substance 3 on a product 5. In Fig. 8 (a), a product 5 and a substrate 13a that is transparent for the electromagnetic radiation 27 emitted by the printing device 23, e.g., a glass substrate, having a first surface 19 on which a layer 17 of viscous substance 3 has been applied, are positioned above each other in the printing position 29. The distance between the surface of the layer 17 of viscous substance 3 facing away from the first surface 19 of the substrate 13a and the first surface of the product 5 onto which the viscous substance 3 is to be printed is at a predetermined distance in the range of 30 micrometres to 400 micrometres. The accuracy of the distance between the surface of the layer 17 and the first surface of the product 5 is in the range of -5 micrometres and 5 micrometres.

[0065] A beam of electromagnetic radiation 27 is transmitted by printing device 23 (not shown) on the substrate 13a. The apparatus 1 according to the first aspect of the present disclosure is arranged for providing the beam of electromagnetic radiation 27 to the first surface 19 of the substrate 13a via a second surface 55 of the substrate 13a. The beam of electromagnetic radiation 27 locally heats the first surface 19 of the substrate 13a and a selective layer-part 37 of the layer 17 of viscous substance 3 causing vaporization within the layer 17 of the viscous substance 3 such that a gas bubble 57 is formed.

[0066] In Fig. 8 (b), the bubble 57 pushes the selective layer-part 37 of the layer 17 of the viscous substance 3 away from the substrate 13a. Viscous substance 3 that is pushed away by the bubble 57 is deposited on the predetermined position on the surface of the product 5. Subsequently in Fig. 8 (c), the substrate 13a is moved upwards (indicated by the black arrows) thereby creating a rupture position (indicated by the dashed circle) such that the selective layer-part 37 of the layer 17 of the viscous substance 3 is being separated from the layer 17 of viscous substance 3. As shown in Fig. 8 (d), the selective layer-part 37 of viscous substance 3 is deposited on the predetermined position on the product 5. Hence, the viscous substance 3 is printed on the product 5.

[0067] A method 101 for printing a viscous substance 3, by means of Laser Induced Forward Transfer, on a product 5 is shown in Fig. 9. The method 101 uses the apparatus 1 and comprises the steps of providing 103 a substrate 13a or a further substrate 13b, which is transparent for the beam of electromagnetic radiation 27, and a product 5; supporting 105 the product 5; and holding 107 the respective substrate 13a, 13b. The holding 107 is done by the substrate carrier 11 comprised by the substrate handler 7.

[0068] The method 101 further comprises the steps of moving 109, by the substrate handler 7, the respective substrate 13a, 13b to the coater 15 by moving the respective substrate 13a, 13b in the virtual plane v and about the first pivoting axis p1 in the virtual plane v; providing 111 , by a docking station of the at least two docking stations 45a, 45b provided in the docking arrangement 43, a first surface 19 of the respective substrate 13a, 13b into the coating position 21 ; providing 113 a layer 17 of the viscous substance 3 on the first surface 19 of the respective substrate 13a, 13b; moving 115, by the substrate handler 7, the respective substrate 13a, 13b to the printing device 23 by moving the respective substrate 13a, 13b in the virtual plane v and about the first pivoting axis p1 in the virtual plane v; providing 117, by the docking station of the at least two docking stations 45a, 45b, the first surface 19 of the respective substrate 13a, 13b into the printing position 29; and emitting 119 the beam of electromagnetic radiation 27 for printing the viscous substance 3, by means of Laser Induced Forward Transfer, on the predetermined position of the product 5.

[0069] In the method 101 , the substrate 13a and the further substrate 13b are provided during the step of providing 103, and wherein, during the step of moving 109 the respective substrate 13a, 13b to the coater 15, the other of the substrate 13a and the further substrate 13b is simultaneously moved to the printing device 23 by moving the other of the substrate 13a and the further substrate 13b in the virtual plane v and about the first pivoting axis p1 in the virtual plane v, and, during the step of moving 115 the respective substrate 13a, 13b to the printing device 23, the other of the substrate 13a and the further substrate 13b is simultaneously moved to the coater 15 in the virtual plane v and about the first pivoting axis p1 in the virtual plane v.

[0070] In the method 101 , the substrate 13a and the further substrate 13b are provided during the step of providing 103, and wherein, during the step of providing 111 the first surface 19 of the respective substrate 13a, 13b in the coating position 21 , the first surface 19 of the other of the substrate 13a and the further substrate 13b is provided in the printing position 29, and, during the step of providing 117 the first surface 19 of the respective substrate 13a, 13b in the printing position 29, the first surface 19 of the other of the substrate 13a and the further substrate 13b is provided in the coating position 21.

[0071] As shown in Fig. 9, the method 101 further comprises the steps of scanning 121 the beam of electromagnetic radiation 27 across the first surface 19 of the respective substrate 13a, 13b for printing the selective layer-part 37 of the viscous substance 3, by means of Laser Induced Forward Transfer; and moving 123 the respective substrate 13a, 13b between the upper position and the lower position in the height direction z.

[0072] In the method 101 , the step of moving 123 the respective substrate 13a, 13b between the upper position and the lower position is performed simultaneously with the step of moving 109 the respective substrate 13a, 13b to the coater 15 and simultaneously with the step of moving 115 the respective substrate 13a, 13b to the printing device 23.

[0073] As becomes clear from Fig. 9, the steps of moving 109, providing 111 , providing 113, moving 115, providing 117, emitting 119, scanning 121 and moving 123 are repeated for providing the viscous substance 3 to predetermined positions of the product 5.

[0074] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the present disclosure, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single unit or component may fulfil the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope thereof. The foregoing description provides embodiments of the present disclosure by way of example only. The scope of the present disclosure is defined by the appended claims. One or more of the objects of the present disclosure are achieved by the appended claims.

Claims

CLAIMS1. An apparatus (1) for printing a viscous substance (3), preferably solder paste or a conductive glue, by means of Laser Induced Forward Transfer (LIFT), on a product (5), the apparatus (1) comprising: a substrate handler (7) having a shaft (9) comprising a substrate carrier (11), the substrate carrier (11) being arranged for holding a substrate (13a) or a further substrate (13b); a coater (15) configured for providing a layer (17) of the viscous substance (3) on a first surface (19) of the respective substrate (13a, 13b) in a coating position (21) of the respective substrate (13a, 13b); a printing device (23) configured for transmitting a beam of electromagnetic radiation (27) for printing the viscous substance (3), by means of Laser Induced Forward Transfer (LIFT), on a predetermined position of the product (5) in a printing position (29) of the respective substrate (13a, 13b); and a docking arrangement (43) comprising at least two docking stations (45a, 45b), the docking arrangement (43) being configured for decoupling the respective substrate (13a, 13b) from the substrate carrier (11) and docking the respective substrate (13a, 13b) to the respective docking station (45a, 45b); wherein the substrate handler (7) is configured for moving the respective substrate (13a, 13b) between the coater (15) and the printing device (23) by moving the respective substrate (13a, 13b) in a virtual plane (v), defined by a longitudinal direction (x) and a width direction (y) and oriented perpendicular to a height direction (z), and about a first pivoting axis (p1) in the virtual plane (v) for bringing the respective substrate (13a, 13b) from the coater (15) to the printing device (23), wherein the at least two docking stations (45a, 45b) are each configured for providing the respective substrate (13a, 13b) into the respective coating position (21) or printing position (29).

2. The apparatus (1) according to claim 1 , wherein the substrate handler (7) comprises a plurality of the substrate carriers (11), wherein the plurality of substrate carriers (11) are mutually equally spaced with respect to each other, and preferably wherein the substrate handler (7) is configured for moving, preferably simultaneously,the other of the substrate (13a) and the further substrate (13b) between the printing device (23) and the coater (15) for bringing the other of the substrate (13a) and the further substrate (13b) from the printing device (23) to the coater (15) for simultaneously coating and printing.

3. The apparatus (1) according to claim 1 or 2, wherein the substrate handler (7) is further configured for bringing the respective substrate (13a, 13b) from the printing device (23) to the coater (15).

4. The apparatus (1) according to any of the preceding claims, wherein the apparatus (1) further comprises a support (31) for positioning the product (5) in relation to the first surface (19) of the respective substrate (13a, 13b) in the respective coating position (21) or printing position (29) of the respective substrate (13a, 13b).

5. The apparatus (1) according to any of the preceding claims, wherein the apparatus (1) further comprises a scanning device (33) arranged for scanning the beam of electromagnetic radiation (27) across the first surface (19) of the respective substrate (13a, 13b) for printing a selective layer-part (37) of the viscous substance (3).

6. The apparatus (1) according to any of the preceding claims, wherein the substrate handler (7) further comprises a displacement arrangement (39) for moving the respective substrate (13a, 13b) between an upper position and a lower position in the height direction (z).

7. The apparatus (1) according to claim 6, wherein the displacement arrangement (39) comprises a constant-velocity joint (41) adapted for allowing the displacement arrangement (39) to rotate freely with respect to the shaft (9) and for compensating for an angle (a1 ,a2) between the displacement arrangement (39) and the shaft (9).

8. The apparatus (1) according to any of the preceding claims, wherein the substrate handler (7) comprises an actuator or at least two circular toothed wheels arranged for pivoting the respective substrate (13a, 13b) about the first pivoting axis(p1) in the virtual plane (v) and optionally about a second pivoting axis (p2) in the height direction (z).

9. The apparatus (1) according to any of the preceding claims, wherein the respective substrate (13a, 13b) is substantially transparent, preferably transparent, for the beam of electromagnetic radiation (27).

10. A method (101) for printing a viscous substance (3), preferably solder paste or a conductive glue, by means of Laser Induced Forward Transfer (LIFT), on a product (5), the method (101) comprising the steps of: providing (103) a substrate (13a) or a further substrate (13b), and the product (5); supporting (105) the product (5); holding (107), by a substrate carrier (11) comprised by a substrate handler (7), the respective substrate (13a, 13b); moving (109), by the substrate handler (7), the respective substrate (13a, 13b) to a coater (15) by moving the respective substrate (13a, 13b) in a virtual plane (v), defined by a longitudinal direction (x) and a width direction (y) and oriented perpendicular to a height direction (z), and about a first pivoting axis (p1) in the virtual plane (v); providing (111), by a docking station of at least two docking stations (45a, 45b) provided in a docking arrangement (43), a first surface (19) of the respective substrate (13a, 13b) into a coating position (21); providing (113) a layer (17) of the viscous substance (3) on the first surface (19) of the respective substrate (13a, 13b); moving (115), by the substrate handler (7), the respective substrate (13a, 13b) to a printing device (23) by moving the respective substrate (13a, 13b) in the virtual plane (v) and about the first pivoting axis (p1) in the virtual plane (v); providing (117), by the docking station of the least two docking stations (45a, 45b), the first surface (19) of the respective substrate (13a, 13b) into a printing position (29);emitting (119) a beam of electromagnetic radiation (27) for printing the viscous substance (3), by means of Laser Induced Forward Transfer (LIFT), on a predetermined position of the product (5).

11. The method (101) according to claim 10, wherein the substrate (13a) and the further substrate (13b) are provided during the step of providing (103), and wherein, during the step of moving (109) the respective substrate (13a, 13b) to the coater (15), the other of the substrate (13a) and the further substrate (13b) is moved, preferably simultaneously, to the printing device (23) by moving the other of the substrate (13a) and the further substrate (13b) in the virtual plane (v) and about the first pivoting axis (p1) in the virtual plane (v), and, during the step of moving (115) the respective substrate (13a, 13b) to the printing device (23), the other of the substrate (13a) and the further substrate (13b) is moved, preferably simultaneously, to the coater (15) in the virtual plane (v) and about the first pivoting axis (p1) in the virtual plane (v).

12. The method (101) according to claim 10 or 11 , wherein the substrate (13a) and the further substrate (13b) are provided during the step of providing (103), and wherein, during the step of providing (111) the first surface (19) of the respective substrate (13a, 13b) in the coating position (21), the first surface (19) of the other of the substrate (13a) and the further substrate (13b) is provided in the printing position (29), and, during the step of providing (117) the first surface (19) of the respective substrate (13a, 13b) in the printing position (29), the first surface (19) of the other of the substrate (13a) and the further substrate (13b) is provided in the coating position (21).

13. The method (101) according to any of the claims 10 to 12, further comprising the step of: scanning (121) the beam of electromagnetic radiation (27) across the first surface (19) of the respective substrate (13a, 13b) for printing a selective layer-part (37) of the viscous substance (3), by means of Laser Induced Forward Transfer (LIFT).

14. The method (101) according to any of the claims 10 to 13, further comprising the step of:moving (123) the respective substrate (13a, 13b) between an upper position and a lower position in the height direction (z).

15. The method (101) according to claim 14, wherein the step of moving (123) the respective substrate (13a, 13b) between the upper position and the lower position is performed simultaneously with the step of moving (109) the respective substrate (13a, 13b) to the coater (15) and / or simultaneously with the step of moving (115) the respective substrate (13a, 13b) to the printing device (23).

16. The method (101) according to any of the claims 10 to 15, wherein one or more of the steps of moving (109) the respective substrate (13a, 13b) to the coater (15), providing (111) the first surface (19) of the respective substrate (13a, 13b) in the coating position (21), providing (113) the layer (17) of viscous substance (3), moving (115) the respective substrate (13a, 13b) to the printing device (23), providing (117) the first surface (19) of the respective substrate (13a, 13b) to the printing position (29), and emitting (119), and optionally scanning (121) the beam of electromagnetic radiation (27) and moving (123) the respective substrate (13a, 13b) between the upper position and the lower position, are repeated for providing the viscous substance (3) to predetermined positions of the product (5).

17. The method (101) according to any of the claims 10 to 16, wherein the respective substrate (13a, 13b) is substantially transparent, preferably transparent, for the beam of electromagnetic radiation (27) emitted during the step of emitting (119).

18. The method (101) according to any of the claims 10 to 17 using the apparatus (1) according to any of the claims 1 to 9.

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