Device and method for filling a trench

Abstract

The present application relates to a deposition system (1), a method and the use of the system for filling grooves (901) in a surface of a workpiece (900) with a printable medium (2), in particular a highly viscous paste. The system comprises at least one deposition head (100) which includes at least one first deposition chamber (111) extending to a first hole (121). The hole is reversibly closed between at least two gate assemblies (201, 202). In certain embodiments, the system is a dual-chamber system each having a reversibly closable hole. The system is configured to maintain flush between the workpiece and the ends of the gate assemblies so as to fill the grooves when working pressure is applied.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method and system for depositing a printable medium in a groove provided in a surface of a workpiece. In particular, it relates to filling the groove with a paste having a high solids content. BACKGROUND OF THE INVENTION

[0002] By using a squeegee to drag a quantity of filling material such as a paste across the surface of the workpiece to fill a groove in the surface, the squeegee is positioned at a forward angle relative to the surface, but disadvantageously is prone to producing an incomplete filling of the groove. For example, because air is trapped beneath the deposited material when the squeegee is pulled across the groove. Specifically, for adhesives and / or conductive materials such as solder paste, incomplete filling can cause failure of the final product, for example due to loss of conductivity. Similar problems are known for screen printing, where a squeegee or a blade is generally used to force a viscous paste through a partially closed screen aperture. The deposition thickness and quality mainly depend on the type of screen, the hardness of the squeegee, the angle of the squeegee, and the printing speed.

[0003] As an alternative to using a squeegee, it has been reported to combine a pumping system with screen printing, and WO0105592A1 discloses a screen printing head for applying a paste-like product to a printing screen. The head includes a chamber having through holes, and the paste-like product is forced through the through holes into the screen. The chamber is laterally confined between a pair of laterally spaced-apart gate plates that are pressed against the screen during use. A diverter positioned between the gate plates provides a circulating flow to facilitate filling of the screen. US201039509A1 improves this concept by providing a rotating cylinder as the diverter. Pumping systems are mainly used for printing solder paste or conductive adhesives in the printed circuit board (PCB) manufacturing industry. Although pumping systems can be used in combination with screen printing (via a cavity), especially in combination with a dedicated screen printing paste, there is still a need for an improved method or apparatus for filling grooves in a substrate of a workpiece. In particular, there is still a need for a device that is configured to set a wider range of materials, such as a paste having a higher solids content, and / or provide one or more of the following: a better deposition rate; better control of the filling degree; less deposition and / or overflow in non-target areas (such as outside the groove); and / or less wear on the workpiece and / or the device (especially a workpiece having a relatively soft outer surface). SUMMARY OF THE INVENTION

[0004] The present application relates to a deposition system for depositing a printable medium in a groove or cavity provided in a surface of a workpiece. The deposition system comprises: a deposition head including a deposition surface; and a drive unit for providing relative movement between the deposition head and the workpiece in a direction transverse to the surface of the workpiece. The deposition head includes a body that includes at least one first deposition chamber. The first deposition chamber is at least partially defined by a recess in the body. The first deposition chamber extends to a first hole that is located in the deposition surface and between at least two gate assemblies. The deposition head further includes at least one first pressurizing mechanism configured to act on the first deposition chamber and configured to apply a first working pressure to a quantity of printable medium received in the first deposition chamber in use. The deposition system further includes at least one first mounting provided on the body. The at least two gate assemblies include a first gate assembly. The first gate assembly includes a first gate blade that extends from the first mounting towards another gate assembly of the at least two gate assemblies to close the first hole between the end of the first gate blade and the end of another gate assembly of the at least two gate assemblies in a closed state. The first gate blade is configured to bend in response to the applied first working pressure to at least partially open the first hole. The drive unit is configured to adjust the relative position between the body and the surface of the workpiece in use so as to maintain flush contact between the surface of the workpiece and the end of the first gate blade and the end of another gate assembly of the at least two gate assemblies while in a bent state in use.

[0005] In a preferred embodiment, the other gate assembly of the at least two gate assemblies includes a partition wall that extends longitudinally through the recess to define a second deposition chamber that is laterally separated from the first deposition chamber. The second deposition chamber extends to a second hole that is located in the deposition surface and between the other gate assembly of the at least two gate assemblies and yet another gate assembly. The yet another gate assembly includes a second gate blade that extends from a corresponding second mounting member toward the other gate assembly of the at least two gate assemblies to close the second hole between the end of the second gate blade and the end of the other gate assembly of the at least two gate assemblies in a closed state. The second mounting member is disposed on the body and passes through the recess to be opposite the first mounting member. The deposition system preferably further includes a second pressurizing mechanism that is configured to act on the second deposition chamber during use and is configured to apply a second working pressure that is generally different from the first working pressure to the printable medium received in the second deposition chamber during use. The second gate blade is configured to bend in response to the applied second working pressure to at least partially open the second hole. A system including a first working chamber and a second working chamber can be understood to constitute a dual-chamber system. The dual-chamber system allows for the deposition of one or more printable media from two separate holes. The printable media in the first chamber and the second chamber are generally the same but can also be different. Double-layer filling can be achieved using two different compounds, for example, using a conductive bottom layer and a more adhesive or protective sealing layer to fill the trench. However, similar compounds or identical compounds are generally used.

[0006] In another or even more preferred embodiment, the first mounting member is configured to adjust the position and / or orientation of the first gate blade relative to the body during use based on at least the first working pressure so as to at least partially offset the contact pressure between the end of the first gate blade and the surface of the workpiece during use.

[0007] According to other aspects, the present application relates to a method of depositing a printable medium in a trench provided in a surface of a workpiece through one or more deposition systems according to the present application. The method includes the steps of applying a first working pressure to the printable medium received in the first deposition chamber to bend the first gate blade so as to at least partially open the first hole while providing relative movement between the body and the workpiece in a direction transverse to the surface of the workpiece so as to maintain flush contact between the surface of the workpiece and the ends of the first gate blade and the other gate assembly of the at least two gate assemblies; and providing relative movement between the deposition head and the workpiece in a lateral direction along the surface of the workpiece to guide the deposition head past the trench and preferably while maintaining the flush contact.

[0008] In a preferred embodiment, and in the case of a system comprising a first working chamber and a second working chamber, also referred to as a dual-chamber system, the method further comprises the steps of: applying a second working pressure to the printable medium received in the second deposition chamber to bend the second flap so as to at least partially open the second aperture when the second working pressure is applied. Preferably, when the deposition head is guided past the groove, when looking in the direction of the lateral movement, if the first aperture is in front and the second aperture is behind, the first working pressure is higher than the second working pressure, or wherein, if the second aperture is in front and the first aperture is behind, the second working pressure is higher than the first working pressure.

[0009] In another or even more preferred embodiment, and in the case where the first mounting of the system is configured to adjust the position and / or orientation of the first flap relative to the body in use in accordance with at least the first working pressure, the method comprises the steps of: repositioning and / or reorienting the first flap relative to the body so as to at least partially counteract the contact pressure between the end of the first flap and the surface of the workpiece.

[0010] According to other aspects, the present application relates to a method or use for cleaning grooves and / or removing soluble or absorbable substances from a workpiece according to the dual-chamber system of the present application. The use at least comprises: depositing a printable medium (a cleaning agent suitable for the substance) from the first deposition chamber onto the workpiece by applying an appropriate first working pressure; and recovering at least a portion of the deposited printable medium via the second deposition chamber by applying an appropriate second working pressure.

[0011] The deposition system according to the present application provides advantages over known methods such as screen printing and / or blade coating. As described in more detail below, these advantages include one or more of the following: a better deposition rate; better control of the filling degree; less deposition and / or spillage onto non-target areas outside the groove, for example; and / or less wear on the workpiece and / or the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other features, aspects and advantages of the devices, systems and methods of the present application can be better understood from the following description, the appended claims and the drawings, in which:

[0013] Figure 1A A cross-sectional side view of the deposition system shown in the closed state;

[0014] Figure 1B A cross-sectional side view of the deposition system shown in the open state;

[0015] FIG. 2 (A, B, C) shows the deposition system in use;

[0016] Figure 3 and4 Cross-sectional side view of the deposition system in the closed and open states;

[0017] Figure 5 Enlarged view of the deposition system in the open state;

[0018] Figure 6A Embodiment showing the gate assembly;

[0019] Figure 6B The gate assembly in the closed and open states;

[0020] Figure 7A With B showing the gate blade bending with pressure;

[0021] Figure 8 Showing the deposition system components;

[0022] Figure 9 Showing trench filling;

[0023] Figure 10 Showing trench cleaning;

[0024] Figure 11 Showing a workpiece with filled trenches; and

[0025] Figure 12 Showing the deposition system in use. Detailed Description

[0026] The terms used to describe particular embodiments are not intended to limit the invention. Unless the context clearly indicates otherwise, the articles "a" and "the" are intended to include the plural forms herein. The phrase "and / or" includes any and all combinations of one or more of the associated listed items. It is to be understood that the terms "comprises" and / or "comprising" specify the presence of the stated features but do not preclude the presence or addition of one or more other features. It is further to be understood that, unless otherwise indicated, when a particular step of a method is referred to as being after another step, it may directly follow that other step or one or more intermediate steps may be performed before the particular step is carried out. Similarly, it is to be understood that, unless otherwise indicated, when describing the connection between structures or components, this connection may be established directly or via intermediate structures or components.

[0027] The systems and methods described herein are not considered limited to any particular printable medium. In principle, the printable medium can be understood to include a variety of compositions such as liquids such as solvents and solvent-based inks, and highly viscous media such as paste products. Solvent-based inks generally contain up to 40 weight percent solids (e.g., copper), and the solvent typically makes up the majority of the total ink volume. This means that when the solvent evaporates, the degree of filling of the trenches is reduced to a fraction of the initial filling degree. For jet inks, even for inks initially containing 20 to 40 weight percent copper, the degree of filling of the trenches is typically reduced to about 3 to 5 volume percent of the initial filling degree. Therefore, 20 to 40 filling cycles are required to completely fill the trenches with the functional material. For more efficient filling, a high content of paste is preferred. Using a high-solid-content paste such as a screen paste (known to have a metal content of 60 to 75 wt%) can reduce the number of filling steps required. For example, a paste in the range of more than 80 wt%, such as a higher content paste of 85 to 99 wt%, such as 95 wt% is even better. However, so far, it has been difficult to quickly fill the trenches due to limitations such as high viscosity. In addition, the drying tendency due to the limited amount of solvent makes it infeasible to apply the medium for filling the trenches.

[0028] It is understood that the systems and methods described herein are particularly advantageous in combination with media having a high viscosity, especially in combination with paste products such as screen paste or higher content paste. The system can even be used to deposit inks or pastes having a viscosity of more than 500 Pa·s (e.g., in the range of about 1000 Pa·s) (Haake RS1 of C20 / 2°TiL at 25 °C for 230 sec). Pastes with a high viscosity are highly unusual in the printing industry and are generally considered unsuitable for known devices and methods, such as screen printing using inks / pastes having a viscosity in the range of up to about 50 Pa·s. A paste with a relatively high solid content (i.e., a more viscous paste) can be used to reduce the number of operations required to obtain a comparable degree of filling. As described in more detail below, the system can further increase the filling rate (equivalent to further reducing the total process time) by, for example, increasing the pressure applied to force a material such as a paste into the trenches. - 1 C20 / 2°TiL's Haake RS1). Pastes with a high viscosity are highly unusual in the printing industry and are generally considered unsuitable for known devices and methods, such as screen printing using inks / pastes having a viscosity in the range of up to about 50 Pa·s. A paste with a relatively high solid content (i.e., a more viscous paste) can be used to reduce the number of operations required to obtain a comparable degree of filling. As described in more detail below, the system can further increase the filling rate (equivalent to further reducing the total process time) by, for example, increasing the pressure applied to force a material such as a paste into the trenches.

[0029] The present invention will be described more fully hereinafter with reference to the accompanying drawings showing embodiments of the invention. In the figures, the absolute and relative dimensions of systems, components, layers, and regions may be exaggerated for clarity. Embodiments may be illustrated with reference to schematic and / or cross-sectional views of possible idealized embodiments and intermediate structures of the present invention. In the description and the figures, like reference numerals refer to like components throughout. Relative terms and their derivatives should be construed to refer to the orientation as described or shown in the description or the figures. These relative terms are for convenience of description and, unless otherwise stated, the system need not be constructed or operated in a particular orientation.

[0030] The deposition system for depositing a printable medium will be described hereinafter with reference to FIG. 1, in which Figure 1A a cross-sectional side view of the deposition system 1 in a closed state is shown and Figure 1B a cross-sectional side view of the deposition system 1 in an open state is shown. For ease of understanding, certain features of depositing the printable medium will be described in more detail later. As Figure 1A and 1B shown, the deposition system includes a deposition head 100. The deposition head 100 includes at least a first deposition chamber 111 that is at least partially defined by a recess 115 in the body and extends to a first hole 121 in a deposition surface 101 (see dashed line) between at least two gate assemblies 201, 202. The hole can be reversibly opened and closed. The distance (or length) of the opening of the hole can be adjusted according to usage conditions (such as the working pressure). Provided on the system are at least a first pressurizing mechanism 141 and a drive unit 20 that is configured to provide relative movement between the deposition head and the workpiece in a direction transverse to the surface of the workpiece. The first pressurizing mechanism 141 acts on the first deposition chamber and is configured to apply a first working pressure WP1 to the printable medium 2 received in the first deposition chamber during use. Generally, the system also includes means for providing relative movement between the deposition head 100 and the workpiece along the lateral direction of the surface of the workpiece. The means may be included in the system, for example, as a conveyor belt. Alternatively or additionally, the drive unit 20 can be configured to provide the lateral movement. Or, the deposition system can be used in combination with another system (such as a production line) that already includes conveying means.

[0031] The at least two shutter assemblies 201, 202 include a first shutter assembly 201. The first shutter assembly includes a first shutter blade 221 that extends from a first mount 211 towards another shutter assembly 202 of the at least two shutter assemblies so as to close a first aperture 121 between an end of the first shutter blade and an end of another shutter assembly of the at least two shutter assemblies in a closed state. The first shutter blade 221 is configured to bend in response to an applied first operating pressure so as to at least partially open the first aperture 121. For example, when an operating pressure is applied, opening the aperture enables the medium 2 to leave the deposition chamber and flow towards the workpiece.

[0032] As shown, the first shutter assembly 201 and another shutter assembly 202 of the at least two shutter assemblies can be understood together as a mechanism for reversibly closing and opening the deposition chamber. The deposition system 1 having a closing mechanism advantageously avoids: when the system is in an idle state, the printable medium 2 overflows or leaks from the deposition head 100 onto a non-target deposition area on the workpiece. The pressure maintained on the printable medium 2 in the idle state is relatively low, close to atmospheric pressure, such that the deposition chamber 111 remains closed. In addition, the shutter assembly can have means for maintaining the closed position by applying a closing force. Suitable means include but are not limited to springs, pneumatic cylinders, electromagnetic switches, etc.

[0033] As described in more detail with respect to FIG. 2, the drive unit 20 is configured to: during use, adjust the relative position between the body 110 and the surface of the workpiece so as to maintain flush contact between the surface of the workpiece and an end of the first shutter blade 221 and an end of another shutter assembly 202 of the at least two shutter assemblies while in a bent state. Maintaining a flush contact during a deposition operation can prevent the printable medium from flowing laterally along the workpiece, for example beyond the shutter blade.

[0034] In some embodiments, for example, as Figure 1A shown, another shutter assembly 202 of the at least two shutter assemblies includes another shutter blade. The another shutter blade extends from a corresponding mount towards an end of the first shutter blade 221, the corresponding mount being provided on the body and opposite the first mount across the recess. Preferably, the another shutter blade is also configured to bend in response to an applied first operating pressure so as to contribute to at least partially opening the first aperture 121. Alternatively, another shutter assembly 202 of the at least two shutter assemblies can be a stationary shutter assembly, such as a protrusion, such as a wall segment of the recess 115 or even an opposite edge of the recess. Thus, the first deposition chamber 111 can be understood as being closable by a single shutter blade.

[0035] Figure 2 shows the deposition system in use for filling the trenches 901 provided in the surface 902 of the workpiece 900. For ease of understanding, some components such as the pressurizing mechanism are not shown. Figure 2A The deposition head 100 is shown in the idle state. The first deposition chamber 111 is filled with the printable medium 2. The hole is in the on-off closed state 121'. Before opening the hole, the deposition head 100 moves in the direction "z" transverse to the surface 902 of the workpiece. The pressure on the ink 2 is kept relatively low so that the end of the first gate assembly 201 remains in contact with the end of the other gate assembly 202 of the at least two gate assemblies. A closing force CF is usually applied to ensure that the hole is in the on-off closed state 121'. When the blade contacts the workpiece, the closing force (if applied) is released, and the working pressure WP of the ink is increased to bend the blade and switch the hole to the open state 121. If necessary, the control unit adjusts the vertical position so that the hole can be opened while the ends of the gate assemblies remain in contact with the workpiece.

[0036] When the hole is open, the ink 2 can be forced into the trench. The resultant force including the pressure applied to the workpiece when the printable medium 2 is discharged from the first hole 121 tends to lift the system from the workpiece. This lift is counteracted by the drive unit 20 appropriately adjusting the relative position between the body and the surface of the workpiece so as to maintain flush contact between the surface of the workpiece and the ends of the first blade 221 and the other gate assembly 202 of the at least two gate assemblies while in the bent state.

[0037] In some embodiments, the drive device is configured to adjust the relative position between the body and the surface of the workpiece based on the measured force between the deposition head 100 and the workpiece. To this end, the system can have a suitable force sensing device such as a dynamometer 30 or a pressure sensor. The output of the device can be used as a control parameter for maintaining the flush contact. In other or additional embodiments, the drive unit is also configured to adjust the angle between the deposition head and the workpiece so as to maintain the flush contact, for example, by tilting or using a θ-stage.

[0038] As Figure 2B shown, the flush contact is maintained when the head 100 is guided (transverse movement L) on the surface of the workpiece. Providing the flush contact at least during the deposition operation can be understood to help restrict the flow of the medium from the head into the trench, thereby preventing material deposition outside the trench.

[0039] As the head passes through the groove, the ink forced into the groove generates a filling front edge "ff" that pushes air out of the groove in a direction following the lateral movement "L" (in front of the end of the gate assembly leading in the direction of the lateral movement L). Pushing the air in front of the end of the front gate assembly can prevent the groove from being incompletely filled due to trapped air bubbles, which can occur, for example, in a method of pushing a certain amount of ink in front of the end of the front blade when coating through the groove using a doctor blade.

[0040] To change and complete the filling process, the head 100 retracts from the workpiece 900. Preferably, the hole is closed before interrupting the flush contact. Closing the hole can be achieved by applying a closing force CF on the gate assembly and / or applying an appropriate negative pressure. Especially for usually very viscous paste products, closing the hole before interrupting the flush contact can prevent residual deposits when pulling the head away from the workpiece.

[0041] The working pressure applied depends on the viscosity of the printable medium 2 and / or the geometry of the groove to be filled and can be determined experimentally. Grooves with a large width-depth ratio (width / depth > 1) generally require a higher working pressure than grooves with a low width-depth ratio. Usually, the working pressure applied can be as high as equal to or greater than 7 bar, for example, in the range from atmospheric pressure to equal to or greater than 6 bar, for example, up to 10 bar or even higher, for example, up to 24 or 30 bar through some syringe systems. Note that at increasingly higher pressures, shorter and / or thicker blades are better for restricting blade bending. The upper limit can be determined by the strength of the gate assembly used (such as the first blade).

[0042] Heating can be carried out to reduce the viscosity of the printable medium. Preferably, the system includes a heater 180 at a position to act locally on the printable medium 2 housed in the deposition chamber, for example, as Figure 3 shown in 4 Heating the printable medium 2 can reduce the viscosity of the ink and can thus increase the deposition rate at a given working pressure. The upper limit of the target temperature depends on the thermal stability of the printable medium, such as the boiling point and / or decomposition temperature of one or more components in its composition. For high-content pastes, the upper limit is usually between 80 and 100 °C. Therefore, the ink is usually heated to a temperature of 30 to approximately 100 °C, for example, 40 to 80 °C or 30 to 70 °C.

[0043] In a preferred embodiment, for example, as Figure 3 shown in 4As shown, another gate assembly 202 of the at least two gate assemblies includes a partition wall 220. The partition wall 220 extends longitudinally through the recess 115 to define a second deposition chamber 112 that is laterally separated from the first deposition chamber 111 by the partition wall 220, or in other words, defines a dual-chamber system. As shown, the first and second mountings are typically disposed along opposite edges of the recess 115, wherein each mounting covers a corresponding hole.

[0044] Typically, as Figure 1B with 3 shown, the dual-chamber system further includes a second pressurizing mechanism 142 that acts on the second deposition chamber and is configured to apply a second operating pressure to the printable medium received in the second deposition chamber during use. As shown, the second deposition chamber 112 extends to a second hole 122 in the deposition surface 111, the second hole being between another gate assembly 202 and yet another gate assembly 203 of the at least two gate assemblies. Figure 3 The gate assembly is shown in the closed position, i.e., the first hole 121' and the second hole 122' are in the closed position. The yet another gate assembly 203 includes a second shutter 223 that extends from a corresponding second mounting 213 towards another gate assembly 202 of the at least two gate assemblies to close the second hole between the end of the second shutter and the end of another gate assembly of the at least two gate assemblies, the second mounting being disposed on the body 110 and passing through the recess 115 opposite the first mounting 211. Similar to the first shutter, the second shutter is preferably configured to bend in response to the applied second operating pressure to at least partially open the first hole.

[0045] The dual-chamber system advantageously provides two holes through which the medium can be deposited into the trenches. The partition wall 220 that separates the first deposition chamber from the second deposition chamber advantageously allows the second operating pressure to be applied in a manner that is substantially independent of the first operating pressure, and vice versa. Applying different operating pressures has been found to provide many benefits including optimal filling.

[0046] As described above with respect to Figure 2, the filling speed can be increased by increasing the working pressure. Compared to a single-chamber system, the dual-chamber system advantageously allows for a greater degree of freedom in choosing the working pressure that can be applied. A major aspect is that, relative to narrow grooves, the functional paste 2 is more likely to flow into wide grooves due to the difference in flow resistance experienced. This means that, especially for workpieces containing multiple grooves, a system operating at a single working pressure can result in non-uniform filling of the grooves. For example, wide grooves may be overfilled compared to narrow grooves. To avoid this situation, for example, to avoid non-uniform filling levels in grooves of different sizes, it may be considered to use only a pressure slightly above atmospheric pressure (referred to as a slightly overpressure) to deposit the ink. However, using a slightly overpressure must reduce the flow rate and thus limit the speed at which the head can move over these grooves, thereby increasing the total time required to process the workpiece.

[0047] Advantageously, providing a dual-chamber system can avoid these situations by using different working pressures in these chambers. Thus, it allows for maintaining or even promoting control over the filling level while increasing the filling speed. When in use, the two chambers sequentially pass over the grooves. The first chamber, i.e., the front chamber, operates at a higher pressure (e.g., an overpressure of 6 bar) to provide an initial filling of the grooves at least at a high deposition rate. The second chamber, i.e., the rear chamber, operates at a lower pressure (e.g., an overpressure of 1 bar) to complete the filling of the grooves. The second gate, i.e., the rear gate, can act as a wiper for controlling the filling.

[0048] Preferably, the holes are separated by a short but sufficient distance to allow a single groove to be filled simultaneously by the two holes and to operate at mutually different working pressures. A greater separation distance between the first hole and the second hole helps to decouple the pressures (reduce the coupling through the groove). In the case of a smaller separation distance, for example, the pressure drop between the two chambers will be reduced via the seepage path along the groove to be filled, thus partially offsetting the benefits of using a dual-chamber system. To avoid interactive coupling when the dual-chamber system passes over the groove, as viewed from the perspective of the workpiece, the area of the partition wall separating the two chambers is preferably more than at least twice, and more preferably at least ten times, the cross-sectional area of the groove (when looking along the groove). In a preferred embodiment, the first hole and the second hole are laterally separated from each other by a distance greater than the maximum depth of the groove to be filled and less than the minimum lateral width of the groove to be filled. The separation distance is typically defined by the thickness of the partition wall. Generally, the partition wall has a width in the range of 1 to about 10 millimeters. A partition wall having a width in this range has been found to be able to reliably fill a wide range of grooves having dimensions in the relevant range.

[0049] As shown in the figure, at least the first blade is positioned at an acute angle relative to the surface of the workpiece. Preferably, the angle is in the range of 15 to 60 degrees, and optimally in the range of 20 to 35 degrees. An angle within this specific range has been found to achieve a good balance between the pressure applied to the workpiece and limitations such as scraping or scratching the medium to be printed.

[0050] The working pressure can in principle be adjusted within a wide range to affect the deposition rate. When not in flush contact with the workpiece, increasingly higher working pressures cause increasing deflection of the blade, so the outward displacement of the trailing end of the blade increases and the distance the hole opens increases. However, when in flush contact, increasing the working pressure can increase the contact pressure between the trailing end and the workpiece. For example, when the deposition head moves laterally across the surface of the workpiece, increasing the contact pressure will increase the wear of the blade and / or scratching of the surface of the workpiece.

[0051] Since the system and the blade are typically used at different operating temperatures and / or in combination with printable media having compositions that may vary significantly, the blade is preferably an elastic blade to avoid the need for frequent blade replacement. Blades formed from plastic compounds have been found to provide a suitable combination of properties including strength, rigidity, and toughness. Blades formed from compounds containing polyaryletherketone (PAEK) polymers have been found to be particularly suitable because the blades have low friction (low viscosity), appropriate strength, rigidity, and toughness. The polyaryletherketone (PAEK) polymers are, for example, PEK (polyetherketone), PEEK (polyetheretherketone), PEKK (poly(etherketoneketone)), PEEKK (poly(etheretheretherketone)), PEKEKK (poly(etherketone-etherketoneketone)), or mixtures thereof. Advantageously, the properties of these polymers remain stable or at least predictable at high temperatures up to 200°C. Particularly preferred compounds include PEEK.

[0052] In an excellent embodiment, the first mounting member is configured to adjust the position and / or orientation of the first blade relative to the body according to at least the first working pressure during use. Adjusting the position and / or orientation of the first blade relative to the body can be understood to include providing rotational and / or translational movement of the first blade relative to the body. Adjusting the position and / or orientation of the first blade can advantageously be understood to constitute a means for opening and closing the closing mechanism, i.e., helping to control the opening width of the hole during deposition, for example, while maintaining flush contact with the workpiece.

[0053] It can be understood that it is advisable to avoid excessive contact forces between these gate assemblies and the workpiece to reduce wear on the gate assemblies and / or the workpiece. When using relatively soft gate blades such as plastic blades and / or in combination with relatively soft workpieces such as plastic substrates, and the plastic substrate is, for example, a PCB or even such as Figure 4 and 5When 3D printing a component of the exemplary workpiece 900 composed of multiple layers 900a, 990b, 990c, 900d and 900e as shown, an excessive contact force between the gate assembly and the workpiece is particularly disadvantageous. As shown in the figure, the deposition head 100 is used to deposit the conductive paste 2 in the trench to form a conductive contact pad for the joint 905 of the embedded electronic device 904. Advantageously, a system including a first mounting member configured to adjust the position and / or orientation of the first blade relative to the body according to at least the first working pressure allows maintaining the contact pressure below a predetermined maximum contact pressure. For relatively soft workpieces and / or systems having blades containing plastic compounds as described above, the inventors have found that the contact pressure between the trailing end of the blade and the workpiece should preferably be kept below about 0.5 bar, more preferably in the range between 0.1 and 0.4 bar, and most preferably about 0.2 or 0.3 bar.

[0054] To maintain a minimum contact pressure between the surface of the workpiece and the end of the blade, the device (especially the first mounting member) is preferably further configured to: adjust the position and / or orientation of the first blade according to at least the first working pressure during use so as to at least partially offset the contact pressure between the end of the first blade and the surface of the workpiece during use. Adjusting the position and / or orientation of the first blade according to at least the first working pressure advantageously allows reducing the contact pressure, thus avoiding excessive contact pressure between the trailing end and the workpiece.

[0055] The cancellation of the contact force can be achieved in a variety of ways described in detail with reference to FIG. 6, where Figure 6A two embodiments 201a and 201b of the first gate assembly are shown. In both embodiments, the mounting member is configured to be rotatable about an axis 211a such that the trailing end of the blade can be pulled away from the closed position without causing movement of the trailing end towards the workpiece (e.g., through the deposition surface 101). In embodiment 201, the axis of rotation is arranged close to the end of the arm extending beyond the trailing end of the blade. Embodiment 201b shows another mounting member configured to rotate along a virtual axis.

[0056] In an excellent embodiment, for example, as Figures 3 to 5 and Figure 6B shown, the first mounting member 211 includes a retraction mechanism configured to retract the corresponding mounting member 211 in the direction along the blade during use. Figure 6BAn installation of a blade 221 showing an idle position and a position in an operating state. In this idle position, the blade contacts the end of the opposite other gate assembly 202. In this open position, the blade retracts a distance RD to reach a retracted position 221'. Also shown is the bending of the blade in the retracted position under the influence of the working pressure applied to the ink in the first deposition chamber 111. Preferably, the blade retracts according to the applied working pressure to prevent the end of the blade from moving through the deposition surface 101, thereby reducing the contact force between the blade and the workpiece while maintaining a flush contact. It can be understood that the opening width W of the hole depends on the sliding distance and the working pressure (the bending distance of the blade).

[0057] In some embodiments, the sliding and / or rotational movement of the blade is controlled according to a predetermined calibration value. Preferably, the system includes a controller such as a feedback controller (e.g., a force feedback controller), which acts on one or more first and second mountings to adjust the position and / or orientation of one or more ends of the blades relative to the body.

[0058] In some embodiments, for example, as Figure 5 shown in connection with Figure 6B the deposition system includes a sliding assembly 260 disposed at the end (the partition wall) of the other gate assembly of the at least two gate assemblies. The sliding assembly 260 extends along the deposition surface 101 and is configured to contact the ends of the first gate assembly (blade) and the second gate assembly (blade) along the opposite ends of the guiding assembly in a closed state. Advantageously, the sliding assembly provides an elongated contact surface for contacting and sliding along the surface of the workpiece during use. The sliding assembly is understood to reduce the contact pressure between the system and the workpiece during use. Preferably, the elongated contact surface comprises or is formed of a low friction and / or wear-resistant material such as a coating, the coating being, for example, a polymer compound comprising a fluoropolymer, the fluoropolymer being, for example, polytetrafluoroethylene (PTFE), nylon, and / or polyaryletherketone (PAEK).

[0059] Generally, the thickness of the blade is in the range of 0.5 to 3 millimeters, and the length (arm) of the blade between the mounting and the end is in the range of approximately 1.5 to 10 millimeters. Figure 7 shows the bending of a typical PEEK blade having a length (arm between the mounting and the end) of 2 to 7 millimeters under pressure at room temperature. Figure 7A The measured bending distance "h" of the end of a PEEK blade having a thickness of 1 millimeter is shown. Figure 7BShow the bending of the brake pad with a similar but 1.6 mm thickness. It can be seen that the bending distance is found to be linearly proportional to the applied pressure. Advantageously, even at high temperatures, such as the above-mentioned preferred operating temperature, this highly predictable relationship can also be found.

[0060] In some embodiments, the deposition system includes an ultrasonic transducer 185. Preferably, the transducer is arranged close to the workpiece, such as at the end of the partition wall or embedded therein, for example, as Figure 4 shown. Positioning the ultrasonic transducer close to the workpiece enables the transducer to act on the printable medium deposited in the groove during use. Sonic vibration treatment can reduce the formation of bubbles in the groove. More importantly, the transducer can contribute to the cleaning operation mode as described in more detail with reference to Figure 5 the deposition system components shown. Figure 8 shown.

[0061] Advantageously, the deposition system disclosed herein can also be used to deposit low-viscosity inks and / or cleaning agents, including but not limited to organic solvents such as ethanol, propanol, and acetone. Especially when combined with sonic vibration treatment, the cleaning agent can be advantageously used to clean the surface and / or groove. To avoid the redeposition of dissolved contaminants on the workpiece when, for example, the solvent evaporates, it is preferred to remove the solvent from the workpiece (e.g., suck it away). As Figure 8 shown, a dual deposition chamber system can be used with this effect to obtain specific benefits. Figure 8 Shown is a system 1' for depositing a cleaning agent 2' from one of the first and second deposition chambers and at least partially recovering the cleaning agent via the other of the first and second deposition chambers. Depositing and then removing the cleaning agent 2' can be achieved by applying a positive working pressure WP1' to one of the corresponding deposition chambers and applying a negative pressure WP2' to the other of the corresponding deposition chambers.

[0062] According to another aspect, the present application relates to deposition system components. Figure 8An exemplary component 1000 is shown. For example, as shown, the component 1000 is configured to sequentially deposit a cleaning agent and a high-solid-content printable medium, the cleaning agent being used to clean grooves provided in the surface of a workpiece, and the high-solid-content printable medium being used to fill the cleaned grooves. To this end, the system includes at least two deposition systems according to the present application configured in series. At least one (preferably two) of these systems is a dual deposition chamber system. Preferably, one of the systems is configured to deposit and remove the cleaning agent. The other system is configured to deposit a printable medium 2, such as a high-solid-content paste, in the cleaned grooves. Optionally, the deposition system assembly may have one or more cleaning systems (such as scraping systems 601, 602, 603), the one or more cleaning systems being configured to selectively remove at least a portion of a certain amount of the printable medium deposited outside the grooves. For example, the component may include one or more scrapers or blowers located between the cleaning and filling units to remove remaining residues of the cleaning agent 2' from the workpiece. Alternatively or additionally, the component may include: one or more scrapers for removing traces of the printable medium 2 remaining on the workpiece in the landing / retracting position; and / or a scraper configured to remove traces of the printable medium deposited along the edge of the workpiece.

[0063] According to other aspects, the present application relates to a method of depositing a printable medium in a groove and the use of the deposition system. The method of depositing a printable medium in a groove provided in the surface of a workpiece includes at least the following steps: providing a deposition system according to the present application; applying a working pressure to the printable medium housed in the first deposition chamber to bend the first shutter so as to at least partially open the first hole, and providing relative movement between the body and the workpiece in a direction transverse to the surface of the workpiece to maintain flush contact between the surface of the workpiece and the ends of the first shutter and the ends of the other shutter assembly of the at least two shutter assemblies; and providing relative movement between the deposition head and the workpiece in a lateral direction along the surface of the workpiece to guide the deposition head past the groove.

[0064] Preferably, the system is the dual-chamber type system. Thus, and in accordance with the description of the dual-chamber system, the method further includes the following steps: applying a second working pressure to the printable medium housed in the second deposition chamber to bend the second shutter so as to at least partially open the second hole when the second working pressure is applied. Preferably, when the deposition head is guided past the groove, if the first hole is in front and the second hole is behind (observed along the direction of the lateral movement), the first working pressure is higher than the second working pressure, or if the second hole is in front and the first hole is behind, the second working pressure is higher than the first working pressure.

[0065] Figure 9Shows experimental results of exemplary trenches 901-1 to 901-4 that are disposed in a workpiece and filled using the dual-chamber system according to the present application. Shown are a first and a second deposition chamber 111, 112, both filled with a printable medium having a viscosity of 1000 Pa·s and a thixotropic index of 4. The system is in flush contact with the workpiece. In the figure, other components of the system (such as the gate) are omitted for easier understanding. The system moves over the workpieces at a velocity Vc in the direction indicated by the corresponding arrow. The working pressure WP1 (P1) in the front deposition chamber 111 (with reference to the direction of movement) is higher than the pressure WP2 (P2) in the rear deposition chamber 112. When the chamber moves over the trenches, the printable medium 2 (paste) is forced into each trench. It can be seen that the paste is selectively deposited in the trenches; substantially no ink is deposited on the area of the workpiece surface 902 adjacent to the trenches. The lower two cross-sectional views show the degree of filling. The upper cross-sectional image corresponds to an operation where the working pressure WP1 in the front chamber is set at 6 bar (overpressure) and the pressure WP2 in the rear chamber is set at 1 bar overpressure. For the lower cross-sectional image, WP2 is changed to 3.5 bar. In both cases the velocity is 0.025 m / s. It can be seen that changing the working pressure in the rear chamber has a significant effect on the degree of filling, so that the degree of filling can be controlled and even substantially completed in a single operation.

[0066] In another or other preferred embodiments, the provided system includes a first mount having a retraction mechanism configured to retract the corresponding gate in a direction along the gate during use. Thus, the method can be understood to include the steps of: retracting the first gate in a direction along the gate to at least partially counteract the contact pressure between the end of the first gate and the surface of the workpiece. As described with respect to the system, retracting the first gate can be understood to contribute to opening the hole and reducing the contact pressure between the workpiece and the gate.

[0067] Typically the method includes the step of closing the one or more holes. Closing the holes after, for example, completing a deposition cycle typically includes: at least reducing the applied working pressure to stop the discharge of the printable medium. Typically, the step of closing the one or more holes includes repositioning the first gate to an idle / closed position. Positioning the gate to the closed position typically includes reversing the applied retraction distance. Alternatively or additionally, closing the hole can include applying a negative pressure to the corresponding working chamber. Irrespective of the type of material being deposited, the step of closing the opened first hole and / or second hole is preferably carried out before interrupting the flush contact.

[0068] Figure 10Disclosed is a method for cleaning trenches. The upper image shows the cleaning of exemplary trenches using a dual-chamber system according to the present application. The system moves across the surface of the workpiece in the direction indicated by the arrow and is in flush contact therewith simultaneously. Similarly, in Figure 9 only the first and second deposition chambers 111, 112 of the system are shown. The workpiece includes four trenches 901-1 to 901-4 initially filled with unhardened resin. The front chamber 111 (operated at a WP1 slightly above atmospheric pressure) contains a cleaning agent. The rear chamber 112 is operated at a negative pressure WP2 to suck up the deposited cleaning agent and suck the deposited cleaning agent out of the trenches. When the cleaning agent is removed, the resin dissolved in the cleaning agent is extracted from the trenches. The lower image shows a cross-section along the trench and shows the degree of filling (portion of resin) accommodated in the trench when the system passes along the trench. It can be seen from the traces that the trenches can be effectively cleaned.

[0069] Figure 11 A photograph of a workpiece 900 with filled trenches 901' is shown. These filled trenches are approximately 250 μm wide and approximately 50 μm deep. These trenches (tracks) are filled with conductive silver paste 2 (DuPont PE828). In this particular workpiece, these trenches have approximately similar dimensions. A single-chamber system has been found to be highly suitable for filling such trenches. Figure 12 A test device 1 used is shown. The device includes Figure 1A a single-chamber system of the type shown, but with a sliding mechanism as described in Figure 3 The device shown includes a translation stage that supports the deposition head 100 and is in contact with the workpiece 900 simultaneously. In the case where the workpiece includes trenches with greater depth and / or width variations, a dual-chamber system would be more effective.

[0070] These trenches are filled at an operating speed of 25 mm / s, using a pressure of 3 bar, and at a temperature of 20 °C. The squeegee is formed of PEEK and has a length and thickness of 6 and 1 mm respectively. As described in Figure 7A under these conditions, the squeegee has a deflection of approximately 150 μm. It can be observed that the surface immediately adjacent to the trench remains particularly clean, indicating that the squeegee performs its work as expected. It can be seen that for this particular device, some material is deposited along the edge of the head, and this material can be eliminated, for example, by a scraping system and / or by improving the seal along the boundary at the end of the deposition head.

[0071] The filled tracks are in contact with a bare die chip (50 μm thick) embedded in 3D printing. After the paste is hardened at a temperature of 100 °C for 5 minutes, all the interconnections are found to function fully.

[0072] For the sake of clarity and conciseness of description, features are described herein as part of the same or individual embodiments. However, it will be understood that the scope of the present invention may include embodiments having combinations of all or some of the said features. Of course, it will be understood that any of the above embodiments or procedures may be combined with one or more other embodiments or processes to provide further improvements in discovery and coordination of design and advantages.

[0073] In describing the appended claims, it should be understood that unless otherwise specifically stated, the term "comprising" does not exclude the presence of other elements or acts than those recited in a given claim; the term "a" before an element does not exclude the presence of a plurality of such elements; any reference numerals in the claims do not limit their scope; several "means" may be represented by the same or different items or by structures or functions that implement the same; any disclosed means or portions thereof may be combined together or divided into other portions. When a claim refers to another claim, this may indicate a synergistic advantage achieved by a combination of their respective features. However, the fact that certain methods are described in mutually distinct claims does not mean that a combination of these methods cannot be used to advantage. Unless the context clearly excludes it, the present embodiments may thus include all working combinations of such claims, where each claim may in principle refer to any of the foregoing claims.

Claims

1. A deposition system (1) for depositing a printable medium (2) into a groove (901) provided in a surface (902) of a workpiece (900), the deposition system (1) comprising: a deposition head (100) including a deposition surface (101); and a drive unit (20) for providing relative movement between the deposition head and the workpiece in a direction transverse to the surface of the workpiece. The deposition head (100) comprises: a body (110) including at least one first deposition chamber (111), the first deposition chamber being at least partially defined by a recess (115) in the body and extending to a first hole (121), the first hole being located in the deposition surface and between at least two gate assemblies (201, 202); a first pressurizing mechanism (141) acting on the first deposition chamber and configured to apply a first working pressure (WP1) to the printable medium (2) received in the first deposition chamber during use; and at least one first mounting member (211) provided on the body (110); the at least two gate assemblies include a first gate assembly (201) comprising a first gate blade (221) extending from the first mounting member towards another gate assembly (202) of the at least two gate assemblies to close the first hole (121) between the end of the first gate blade and the end of another gate assembly of the at least two gate assemblies in a closed state, the first gate blade (221) being configured to bend in response to the applied first working pressure to at least partially open the first hole (121); and Among them, the drive unit (20) being configured to: adjust the relative position between the body (110) and the surface of the workpiece during use so as to maintain flush contact between the surface (902) of the workpiece (900) and the end of the first gate blade and the end of another gate assembly of the at least two gate assemblies while in a bent state, wherein the first mounting member is configured to adjust the position and / or orientation of the first gate blade relative to the body during use based on at least the first working pressure so as to at least partially counteract the contact pressure between the end of the first gate blade and the surface of the workpiece during use, thereby maintaining flush contact between the surface of the workpiece and the end of the first gate blade and the end of another gate assembly of the at least two gate assemblies during use; and / or Wherein, another gate assembly of the at least two gate assemblies includes a partition wall that extends longitudinally through the recess to define a second deposition chamber that is laterally spaced from the first deposition chamber; the second deposition chamber extends to a second hole that is located in the deposition surface and between another gate assembly of the at least two gate assemblies and yet another gate assembly, and the yet another gate assembly includes a second shutter that extends from a corresponding second mounting member toward another gate assembly of the at least two gate assemblies to close the second hole between the end of the second shutter and the end of another gate assembly of the at least two gate assemblies in a closed state, the second mounting member is disposed on the main body and passes through the recess to be opposite to the first mounting member, and the deposition system further includes a second pressurizing mechanism (32) that acts on the second deposition chamber and is configured to apply a second working pressure to a printable medium received in the second deposition chamber during use, and the second shutter is configured to bend in response to the applied second working pressure to at least partially open the second hole.

2. The deposition system according to claim 1, wherein the first mounting member includes a retracting mechanism that is configured to retract the corresponding shutter in a direction along the shutter during use.

3. The deposition system according to claim 1, further comprising a sliding assembly (260) that is disposed at an end of another gate assembly of the at least two gate assemblies and extends along the deposition surface, and is configured to contact the end of the first shutter and the end of the second shutter at opposite ends of the sliding assembly in a closed state, and the sliding assembly provides an elongated contact surface for contacting and sliding along the surface of the workpiece during use.

4. The deposition system according to claim 1, wherein the first hole and the second hole are laterally separated from each other by a distance in the range of 1 to 10 millimeters.

5. The deposition system according to claim 1, configured to: deposit a cleaning agent from one of the first deposition chamber and the second deposition chamber during use, and at least partially recover the cleaning agent via the other of the first deposition chamber and the second deposition chamber by applying a positive working pressure to one deposition chamber of the corresponding deposition chambers and applying a negative pressure to the other corresponding deposition chamber of the corresponding deposition chambers.

6. The deposition system according to claim 1, wherein another gate assembly of the at least two gate assemblies includes another shutter that extends from a corresponding mounting member toward the end of the first shutter, and the corresponding mounting member is disposed on the main body and passes through the recess to be opposite to the first mounting member.

7. A deposition system assembly (1000) that includes at least one deposition system according to any one of the preceding claims and at least one deposition system according to claim 5, and is configured to sequentially deposit a cleaning agent and a high-solid-content printable medium, the cleaning agent being used to clean grooves provided in the surface of a workpiece, and the high-solid-content printable medium being used to fill the cleaned grooves.

8. A method of depositing a printable medium, the method comprising depositing the printable medium in a groove provided in a surface of a workpiece by means of a deposition system according to claim 1, the method comprising the following steps: Applying a first operating pressure to the printable medium received in the first deposition chamber to bend the first shutter to at least partially open the first aperture, while providing relative movement between the body and the workpiece in a direction transverse to the surface of the workpiece so as to maintain flush contact between the surface of the workpiece and the ends of the first shutter and of another shutter assembly of the at least two shutter assemblies; and Providing relative movement between the deposition head and the workpiece in a lateral direction along the surface of the workpiece to guide the deposition head past the groove.

9. The method according to claim 8, wherein the deposition system is a deposition system according to claim 1, and the method further comprises the following steps: Applying a second operating pressure to the printable medium received in the second deposition chamber to bend the second shutter to at least partially open the second aperture when the second operating pressure is applied, Among them, When the deposition head is guided past the groove, when viewed in the direction of the lateral movement, if the first aperture is in front and the second aperture is behind, the first operating pressure is higher than the second operating pressure, or wherein, if the second aperture is in front and the first aperture is behind, the second operating pressure is higher than the first operating pressure.

10. The method according to claim 9, wherein the deposition system is a deposition system according to claim 2, and the method comprises the following steps: Retracting the first shutter along the direction of the shutter to at least partially counteract the contact pressure between the end of the first shutter and the surface of the workpiece.

11. The method according to claim 10, wherein the deposition system is a deposition system according to claim 5, and wherein the printable medium is a cleaning agent, and the method further comprises the following steps: when the first operating pressure is applied, applying a second operating pressure which is a negative pressure to the second deposition chamber to recover at least a portion of the cleaning agent.

12. The method according to claim 8, further comprising the following step: closing the at least partially open first aperture and / or second aperture before interrupting the flush contact.

13. Use of a deposition system according to claim 5 for removing soluble or absorbable substances from a workpiece, the use comprising: Depositing a printable medium from the first deposition chamber onto the workpiece by applying an appropriate first operating pressure, wherein the printable medium is a cleaning agent suitable for the substance; and recovering at least a portion of the deposited printable medium via the second deposition chamber by applying an appropriate second operating pressure.

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