Apparatus and method for adhering printing material to a substrate

Abstract

The present invention relates to an apparatus for depositing a printing material onto a substrate. The apparatus includes a light-transmitting plate having a first surface and a second surface opposite the first surface, the first surface providing a light-receiving surface for receiving light emission signals, the second surface including at least one deposition cavity configured to hold the printing material before deposition, the first surface configured to cooperate with a light source for receiving light emission signals, the at least one deposition cavity including one or more walls forming an interface between the at least one deposition cavity and the transmissive plate, the one or more walls including a multilayer release stack, the multilayer release stack including a light-absorbing layer and a light-blocking layer.

Description

Technical Field

[0001] The present invention relates to an apparatus for adhering a printing material onto a substrate. The apparatus includes a light transmissive plate having a first surface and a second surface opposite the first surface, the first surface providing a light receiving surface for receiving a light emission signal, the second surface including at least one adhesion cavity configured to hold the printing material before adhesion, and the first surface being configured to cooperate with a light source to receive the light emission signal. Further, the present invention relates to a method for adhering dots of a printing material onto a substrate using an apparatus as described above.

Background Art

[0002] High-throughput adhesion of ultra-fine (finer than 60 microns) dots or patterns of interconnecting materials (such as fine type solder paste or conductive adhesives) is impossible with commercial printing techniques such as stencil printing, dispensing, jetting, etc. Instead, alternative methods can be applied to enable the adhesion of such materials in a manufacturing process, for research purposes, or for other purposes.

[0003] One such alternative adhesion method is provided by an adhesion technique called laser-induced forward transfer (LIFT). This technique uses a light source such as a laser to print a small amount of material from a thin donor layer onto a receiver substrate. To do this, a light transmissive plate (printing plate) includes a surface with printing or adhesion cavities. These cavities hold the printing material to be adhered onto a substrate located under the light transmissive plate for adhesion. The opposite or back side of the light transmissive printing plate is selectively irradiated by a light signal such as a laser pulse. LIFT is based on the principle that the irradiated printing material within the cavity is heated and gas is generated by evaporation, causing it to be extruded from the cavity. To heat the printing material, a light absorption layer can be provided on the walls of the cavity to absorb the light emission and convert it into heat.

[0004] LIFT technology is a promising technique for efficiently adhering a wider range of printing materials onto substrates, but controlling the adhesion process is difficult for various reasons. Consequently, the adhesion results are not always satisfactory. For example, differences in the amount of heat transferred to different parts of the cavity can cause unpredictable evaporation in different areas of the cavity. As a result, material droplets can be released from the cavity, but the direction of release can be arbitrary. Also, due to surface tension, unpredictable and non-uniform evaporation can cause droplets to break apart, leading to undesirable printing results.

[0005] To overcome this problem, various improvements to this process have been proposed. For example, U.S. Patent Application Publication 20170268100 seeks improvement by relying on a diffused light profile from a high-intensity flash lamp, with the intention of achieving a uniform heat flux distribution within the cavity. However, here, the incident heat profile cannot be made sufficiently uniform because the incident light is reflected within the carrier plate. Furthermore, U.S. Patent Application Publication 20180171468 proposes diffusing the incident light profile by introducing a diffusion pattern on the back side of the carrier. However, the diffusion of incident light is insufficient to achieve uniformity over the small dimensions of the cavity.

[0006] International Publication No. 2021201681 suggests that applying dichroic mirrors before the absorption layer is more efficient in achieving uniform absorption of the incident profile within the cavity. However, this solution imposes many difficult constraints on the cavity design in order to achieve the dichroic mirror effect. First, each layer must be thinner than the wavelength of the incident light (to avoid direct absorption effects) and at the same time, it must withstand thermal shock while the absorption layer is heated. Second, the complex stack configuration of the proposed dichroic mirrors is highly dependent on the angle of the sidewalls and therefore needs to be modified and adjusted to match the angle and shape of the cavity. [Overview of the project] [Problems that the invention aims to solve]

[0007] The objective of the present invention is to provide a method for adhering printing materials to a substrate that is suitable for a wide range of printing materials and enables the adhesion of ultrafine dots, resulting in predictable and desirable printing results. [Means for solving the problem]

[0008] For this purpose, an apparatus for depositing a printing material onto a substrate as described above is provided. In this apparatus, at least one deposition cavity includes one or more walls that form an interface between the at least one deposition cavity and a transmissive plate, the one or more walls include a multilayer release stack, the multilayer release stack includes a light-absorbing layer and an obstruction layer, the light-absorbing layer is adjacent to the light-transmissive plate and configured to convert light energy from a light emission signal into heat, the obstruction layer is located between the light-absorbing layer and the inside of at least one deposition cavity, the obstruction layer includes one or more heat-shielding layers, the light-absorbing layer has a first thermal conductivity greater than the further thermal conductivity of the one or more heat-shielding layers, thereby enabling lateral heat transfer within the light-absorbing layer and uniformly distributing the heat across the light-absorbing layer when conducting heat to the printing material in the at least one deposition cavity through the obstruction layer before the deposition of the printing material.

[0009] In the apparatus according to the present invention, the inhibiting layer provides a heat barrier that reduces direct heat transfer from the light-absorbing layer to the printing material in the cavity. Since the light-absorbing layer has a first thermal conductivity greater than the further thermal conductivity of one or more heat-shielding layers forming the inhibiting layer, heat is conducted more easily within the light-absorbing layer. Therefore, if the heat is unevenly distributed across the light-absorbing layer due to irradiation, the heat is conducted more easily by lateral heat transfer through the light-absorbing layer. Thus, the inhibiting layer (or "thermal inhibiting layer") prevents rapid heat transfer to the printing material and prevents uneven distribution of heat within the printing material. Before the majority of the heat reaches the printing material, the heat is first uniformly distributed throughout the absorption layer. Therefore, printing is better controlled and the printing results are more predictable. This makes it possible to deposit ultrafine dots on a wide range of printing materials, resulting in predictable and desirable printing results.

[0010] In some embodiments, the light source is a collimated light source for receiving the light emission signal as a collimated light emission signal. The advantage of using a collimated light source lies in the fact that the alignment of the light signal results in a uniform dispersion of the light emission received at the light-receiving surface of the light-absorbing layer, i.e., at the interface between the light-transmitting material of the light-transmitting plate and the light-absorbing layer. As can be understood, when the light emission is collimated, the difference in the amount of radiation received per unit surface area of ​​the light-receiving surface of the light-absorbing layer exists only if a portion of the light-receiving surface has a characteristic orientation (e.g., deviating from the rest of the light-receiving surface). As will be discussed later, such portions of the surface may be present due to the design of the adhesion cavity.

[0011] In other or further embodiments, the apparatus further includes or is configured to cooperate with a light source, which is a pulsed laser light source capable of receiving an optical emission signal as a limited-time optical pulse. By using a pulsed laser, the process can be controlled, for example, by selectively irradiating each single deposition cavity of a light-transmitting plate. Furthermore, the amount of optical emission delivered to each deposition cavity can be appropriately controlled using the pulsed laser, for example, by changing the pulse duration or duty cycle, or by modifying the time-dependent intensity profile of each pulse.

[0012] In yet another embodiment, the inhibiting layer has a second thermal conductivity, which is determined by the further thermal conductivity of one or more heat shielding layers, and the first thermal conductivity of the light absorbing layer is greater than the second thermal conductivity of the inhibiting layer. Referring to the above invention, this type of embodiment distinguishes between the thermal conductivity of each heat shielding layer (referred to as the further thermal conductivity) and the thermal conductivity of the inhibiting layer (referred to as the second thermal conductivity). These two may be different, for example, when multiple heat shielding layers together form an inhibiting layer, or when part of the inhibiting layer is made of heat shielding layers of different materials. For example, the sidewalls of an adhesion cavity, which generally receive little light radiation per unit surface area, may have an inhibiting layer made of different heat shielding layers for the purpose of either lowering or increasing the thermal conductivity. This allows for more precise control and design of heat conduction to the adhesion cavity.

[0013] In some of these embodiments, the inhibiting layer has a thickness that depends on a first thermal conductivity and a second thermal conductivity to allow for the homogenization of heat. As can be understood, the balance of heat conducted through the inhibiting layer or within the light-absorbing layer depends not only on the thermal conductivity but also on the dimensions of these layers, such as their thickness. Therefore, if a specific ratio of thermal conductivity determined by the material selected for these layers, for example, if the first thermal conductivity to the second thermal conductivity is in a specific ratio with respect to each other, then if a specific ratio of heat conducted per unit time is desired, this can be achieved by appropriately selecting the thicknesses of these layers relative to each other. In this regard, the pulse duration and time-dependent intensity profile of the light emission also play a role here. However, considering only thermal conductivity and thickness, the amount of heat q conducted per surface area by a material layer of thickness l is given by a thermal conductivity of k m And when it is caused by a temperature difference ΔT = T2 - T1, it is given by the following equation.

[0014] q=k m ΔT / l

[0015] Therefore, if the initial temperature is known (or can be estimated), a preferred thickness can be calculated from the desired initial heat flux ratio. Assuming that the printing material in the adhesion cavity is at room temperature (293k) at the start of printing, if the initial temperature difference across the light-absorbing layer is determined or estimated (for example, based on the amount of light radiation absorbed), then a preferred thickness can be calculated from this to achieve a heat flux ratio of 10:1 between the internal heat flux q1 through the light-absorbing layer and the heat flux q2 through the inhibiting layer (i.e., a ratio of q1:q2 of 10:1). Thus, similarly in some further embodiments, the light-absorbing layer has a thickness that depends on a first thermal conductivity and a second thermal conductivity to allow for the homogenization of heat.

[0016] In some embodiments, the inhibiting layer includes multiple thermal barrier layers. While a single appropriately selected thermal barrier layer is often sufficient and preferable as the inhibiting layer, applying two or more thermal barrier layers may be advantageous in some designs to obtain specific beneficial effects. For example, by providing an additional thermal diffusion layer between two thermal barrier layers, further redispersion of heat within the thermal diffusion layer can be obtained.

[0017] In some of these embodiments, the second thermal conductivity of the inhibiting layer is provided by the combined thermal conductivity of the further thermal conductivity of the multiple thermal barrier layers forming the inhibiting layer. From the thermal conductivity of each layer, the combined thermal conductivity or effective thermal conductivity of the inhibiting layer can be determined.

[0018] In some embodiments, the light-absorbing layer is provided by a material layer made of a first material, the first material comprising at least one of metals or alloys. Preferably, the first material is a material that has very high thermal conductivity while also being usable as a light-absorbing layer. For example, metallic molybdenum (Mo) or its alloys are good candidates. On the other hand, in other embodiments or further embodiments, at least one of one or more heat-shielding layers comprises or is provided by a material layer made of a second material, the second material comprising at least one of ceramics, polymers, or composite layers. For example, ceramics such as silicon nitride (SiN) are good candidates. According to a particular embodiment, at least one of the material-absorbing layers comprises a molybdenum-chromium alloy, or at least one of one or more heat-shielding layers comprises silicon nitride.

[0019] A second aspect of the present invention provides a method for depositing dots of a printing material onto a substrate using the apparatus described in any one or more of the above claims. The apparatus includes a light-transmitting plate having a first surface and a second surface opposite the first surface, the first surface providing a light-receiving surface for receiving a light emission signal, and the second surface including at least one adhesion cavity configured to hold the printing material before the printing material is deposited, the method comprising filling the at least one adhesion cavity with the printing material and selectively irradiating at least a portion of the light-receiving surface with a light emission signal, thereby transmitting the light emission signal to the at least one adhesion cavity via the transmissive plate and depositing the printing material onto the substrate, the light emission signal being transmitted to the at least one adhesion cavity through a multilayer release stack including a light-absorbing layer and an inhibitory layer, the light-absorbing layer converting the light energy from the light emission signal into heat, and before the printing material is deposited, the inhibitory layer reduces the conduction of heat from the light-absorbing layer to the at least one adhesion cavity in order to allow lateral heat transfer within the light-absorbing layer and to uniformly distribute the heat across the light-absorbing layer.

[0020] In some embodiments, the light emission signal is a collimated light emission signal. Furthermore, in some embodiments, the apparatus further includes a light source or is configured to cooperate with a light source, the light source being a pulsed laser light source capable of receiving the light emission signal as a limited-time light pulse.

[0021] In other embodiments or further embodiments, in the apparatus according to the first embodiment or the method according to the second embodiment, the printing material is at least one of interconnecting materials, solder paste, adhesives, resins, inks, or polymers for use on a substrate.

[0022] The present invention will be further clarified by the description of some specific embodiments while referring to the accompanying drawings. The detailed description provides possible embodiments of the present invention, but should not be considered as only describing the embodiments included in its scope. The scope of the present invention is defined by the claims, and the description should not be construed as limiting the present invention, but should be regarded as exemplary.

Brief Description of the Drawings

[0023] [Figure 1] Schematically shows an apparatus according to an embodiment of the present invention. [Figure 2] Schematically shows an enlarged view of an adhesion cavity in an apparatus according to an embodiment of the present invention. [Figure 3A] Schematically shows an adhesion process according to an embodiment using an apparatus according to an embodiment of the present invention. [Figure 3B] Schematically shows an adhesion process according to an embodiment using an apparatus according to an embodiment of the present invention. [Figure 3C] Schematically shows an adhesion process according to an embodiment using an apparatus according to an embodiment of the present invention. [Figure 3D] Schematically shows an adhesion process according to an embodiment using an apparatus according to an embodiment of the present invention. [Figure 4A] Shows the adhesion problem caused by non-uniform cavity temperature. [Figure 4B] Shows the adhesion problem caused by non-uniform cavity temperature. [Figure 5A] Shows a comparison between the printing result obtained by the printing process of the present invention and the result without the proposed multi-layer release stack. [Figure 5B] Shows a comparison between the printing result obtained by the printing process of the present invention and the result without the proposed multi-layer release stack.

Modes for Carrying Out the Invention

[0024] The terminology used to describe specific embodiments is not intended to limit the invention. The singular forms “a,” “an,” and “the” as used herein are intended to include the plural unless the context clearly indicates otherwise. The term “and / or” includes any and all combinations of one or more of the relevant list items. The terms “comprises” and / or “comprising” are understood to specify the presence of a described feature, but not to exclude the presence or addition of one or more other features. Furthermore, where a particular step of a method is referred to as following another step, unless otherwise specified, this particular step may follow the other step directly or one or more intermediate steps may be performed before the particular step is performed. Similarly, where connections between structures or parts are described, these connections are understood to be established directly or via intermediate structures or parts, unless otherwise specified.

[0025] The present invention will be described in more detail below with reference to the accompanying drawings illustrating embodiments of the present invention. In the drawings, absolute and relative sizes of systems, components, layers, and areas may be exaggerated for clarity. Embodiments can be described with reference to idealized embodiments of the present invention and schematic and / or cross-sectional views of intermediate structures. In the description and drawings, the same number refers to the same element. Relative terms and their derivatives should be interpreted as referring to the direction (orientation) described at that time, or the direction shown in the drawings being discussed. These relative terms are used for explanatory convenience, and unless otherwise specified, it is not necessary to construct or operate the system in a particular direction.

[0026] Figure 1 shows an apparatus or configuration 1 according to one embodiment of the present invention. Apparatus 1 is suitable for depositing a printing material 16 onto a substrate 5. In fact, apparatus 1 can deposit a portion 21 of the printing material 16 onto the surface 6 of the substrate 5. The printing material 16 is deposited by the formation of droplets 20 that are extruded from an adhesion cavity 15 filled with the printing material 16 before ejection. Apparatus 1 is suitable for and can be used for laser-induced forward transfer (LIFT) of the printing material 16.

[0027] Apparatus 1 includes a light-transmitting plate 2. The light-transmitting plate 2 can be made of a light-transmitting material such as quartz or other types of transparent crystals or minerals, a type of glass, a transparent polymer, a transparent resin, or other transparent materials that provide suitable optical and thermodynamic properties. With regard to the latter, it is preferable that the material forming the light-transmitting plate 2 effectively transmits the irradiated light emission signal 10 and transmits most of it, thereby preventing as much heat formation as possible within the light-transmitting plate 2. The light-transmitting plate 2 includes a first surface 3 and a second surface 4 opposite the first surface 3. The first surface 3 provides a light-receiving surface that receives the light emission signal 10 from the light source 11. The second surface 4 includes one or more, preferably a plurality of adhesion cavities 15. The adhesion cavities 15 are configured to hold the printing material 16 before adhesion. It is preferable that the second surface 4 of the light-transmitting plate 2 has a plurality of regularly arranged adhesion cavities 15. For example, this regular arrangement can form a matrix of pixels or other regular arrangements of pixels. Then, by selectively irradiating such pixels under the control of, for example, a controller (not shown) or a control system (not shown), the printing or adhesion of the printing material 16 can be performed.

[0028] The first surface 3 is configured to cooperate with the light source 11 to receive the light emission signal 10. In Figure 1, the light source 11 moves relative to the light-transmitting plate 2 in the direction indicated by the arrow 12. To understand this, the plate 2 can be moved while the light source 11 remains fixed, or both the light-transmitting plate 2 and the light source 11 can be moved to produce the relative motion indicated by the arrow 12 in Figure 1. The light source 11 moves over each adhesion cavity 15 and selectively irradiates the cavity 15 with the light emission signal 10. When the cavity 15 is irradiated, the printing material is released from the cavity 15 to form droplets 20, which adhere to the surface 6 of the substrate 5 as printed portions 21.

[0029] In areas where the adhesion cavity 15 does not need to be illuminated (because it has not been selected as the target of illumination), the light source 11 can provide the light emission signal 10 as a continuous signal that is temporarily blocked by an optical obstruction, such as a shutter. The cavity 15 can be selectively illuminated by moving away from the optical obstruction. Alternatively, the light source can be selectively activated to emit the light emission signal 10 as light pulses. The pulses may contain sufficient light energy (preferably dispersed over time) to cause adhesion of the printing material 16 from the cavity 15. As yet another option, the light emission signal 10 provided by the light source 11 may be a pulsed laser beam consisting of a pulse train (continuous or discontinuous) that can selectively block or transmit pulses. This can be achieved, for example, by using an optical obstruction such as a controllable shutter, or by selectively switching the light source on and off.

[0030] Referring to Figure 2, for adhesion, the adhesion cavity 15 includes walls 23 covered by a multilayer release stack 18. Each cavity 15 of the adhesion cavity 15 includes one or more walls 23 that form an interface between the adhesion cavity 15 and the light-transmitting plate 2. The walls 23 include a multilayer release stack (laminated) 18. The multilayer release stack 18 includes a light-absorbing layer 25 and an inhibiting layer 26. The light-absorbing layer 25 is adjacent to the light-transmitting plate 2 and is configured to convert light energy from the light-emitting signal 10 into heat, for example, to collect heat. The light-absorbing layer 25 can be made of a material that effectively converts the light signal into heat at the light wavelengths contained in the signal. Thus, the selection of the material for the light-absorbing layer 25 can be (optionally) matched to the light-emitting signal 10 provided by the light source 11. As can be seen, some materials are known to be perfect absorbers for a wide range of optical wavelengths, in which case it may not be necessary to match the selection of the material for the light-absorbing layer 25 to the light-emitting signal 10 of the light source 11. Furthermore, as will be described later, the material forming the light-absorbing layer 25 is selected to be a good thermal conductor.

[0031] The inhibiting layer 26 is located between the light-absorbing layer 25 and the inside of the adhesion cavity 15. The main role of the inhibiting layer 26 is to slow down heat transfer between the light-absorbing layer 25 and the printing material 16 in the adhesion cavity 15. This may sound counterproductive, but in fact brings significant advantages to the apparatus 1 of the present invention. This function of the inhibiting layer 26 slows down heat conduction between the light-absorbing layer 25 and the printing material 16, allowing more time for heat to be uniformly dispersed within the light-absorbing layer 25. Thus, the inhibiting layer 26 comprises one or more heat-shielding layers. In the most common approach, and according to one of the important embodiments, the inhibiting layer 26 comprises only a single heat-shielding layer forming the inhibiting layer 26. However, it is certainly possible to provide an inhibiting layer 26 having multiple layers made of different materials or a series of materials in order to obtain certain advantageous effects. In relation to each other, the light-absorbing layer 25 has a first thermal conductivity greater than the further thermal conductivity of the (one or more) heat-shielding layers forming the inhibiting layer 26. As a result, heat is conducted more easily within the light-absorbing layer 25 than when passing through the inhibiting layer 26. Consequently, lateral heat transfer is achieved within the light-absorbing layer 26, and the amount of heat is uniformly distributed across the light-absorbing layer 25. At the same time, the amount of heat is conducted (more slowly) through the inhibiting layer 26 to the printing material 16 in the adhesion cavity 15, so that the heat is effectively and uniformly distributed across all walls 23 (and all parts thereof) before the printing material 16 adheres.

[0032] In Figure 1, the multilayer release stack 18 is used as a set of layers covering all (or most) of the second surface 4 of the light-transmitting plate 2. This is possible according to a particular type of embodiment. However, in some other embodiments or further embodiments, the multilayer release stack 18 is located only inside the cavity 15, as shown, for example, in Figure 2. In this latter case, heat conduction to the adjacent cavity 15 via the light-absorbing layer 25 is more effectively prevented, and heat is more efficiently transferred to the irradiated cavity 15.

[0033] Suitable materials for the light-absorbing layer 25 include metals or metal alloys such as molybdenum (Mo) or molybdenum alloys. For example, in some embodiments, the light-absorbing layer 25 is made of a molybdenum-chromium (MoCr) alloy. Other metals or their alloys, such as iron, aluminum, or other metals, can also be used. The inhibiting layer 26 can consist of a thermal insulator or dielectric such as silicon nitride (SiN), polymer, or resin. Furthermore, the dimensions of the layers can be selected in the design of the apparatus 1. For example, the thickness of the light-absorbing layer 25 can be 10 times that of the inhibiting layer 26. In one embodiment, a light-absorbing layer 25 made of molybdenum-chromium (MoCr) with a thickness of 500 nm (nanometers) is used, and the inhibiting layer 26 is made of silicon nitride (SiN) with a thickness of 50 nm. By adjusting the thickness of each layer to other relevant parameters, and considering the heat conduction within each layer 25 and 26, and a specific temperature difference, a desired amount of heat conduction related to heat conduction in other layers can be obtained. The initial temperatures in various parts of the light-absorbing layer 25 and the inhibiting layer 26 can be estimated, as can the initial temperatures within each layer 25 and 26 and within the printing material 16. From this, the desired initial heat transfer amounts within and between all layers can be determined based on the thermal conductivity of each layer 25, 26 and the printing material 16. The time distribution of light energy can also influence this and can even be used to optimize the deposition process. Since this can determine the preferred thickness of each layer, it is practically impossible to indicate a preferred thickness range for each layer (this depends on the thermal and optical properties of the other layers). Therefore, without limiting the invention, only rough estimates of the thickness range can be provided here. For the light-absorbing layer 25, this can be less than 2 micrometers (less than 2000 nm). For the inhibiting layer 26, at least a certain thickness is desired, for example, 30 nm to 1000 nm. These layers can be coated onto the wall or deposited onto the wall using layer growth techniques (e.g., atomic layer deposition (ALD) or chemical vapor deposition (CVD)). To prevent the multilayer release stack 18 from being present between the adhesion cavities 15, selective removal techniques such as etching or grinding can be used.The depth of the cavity 15 can be approximately a few micrometers, tens of micrometers, or hundreds of micrometers. It is preferable to round or bend the corners of the wall 23 that forms the adhesion cavity 15, as this can have a positive effect on the flow of heat.

[0034] Figures 3A to 3D illustrate the operating principle of the present invention. Figure 3A shows that the light emission signal 10 irradiates the cavity 15. Inside the cavity is the printing material 16 that was applied to the cavity 15 before the start of the deposition method or between the two subsequent printing steps. Preferably, the light emission signal 10 irradiates the entire light-absorbing layer 25 that surrounds the cavity 15 and covers its walls 23. Preferably, the light emission signal is a collimated light signal such that the beam energy is uniformly distributed across the cross-section of the beam. However, in this case, although light energy is received everywhere in the light-absorbing layer 25, it is not received uniformly everywhere. It is clear that the side walls of the cavity are at a different angle to the beam providing the light emission signal 10 compared to the top wall 23 (which crosses the beam). Therefore, the top wall 23 receives the most light emission energy per unit area, while the side walls receive very little light energy per unit area because the receiving angle is oblique. For example, after completely absorbing the light pulse, the side wall 23 remains colder than the top wall 23.

[0035] Figure 3B illustrates the function of the inhibiting layer 26. A magnified view of a portion of the adhesion cavity wall 23 is shown in circle 30. Because the thermal conductivity of the inhibiting layer 26 is lower, the heat flow 35 within the light-absorbing layer 25, stimulated by temperature differences between various parts of the wall 23, is maximized. Thus, heat is rapidly redispersed within the light-absorbing layer 25 and transferred through the inhibiting layer 26. As the temperature differences within the light-absorbing layer 25 become more uniform and the heat dispersion more evenly distributed, the heat flow 35 within the light-absorbing layer 25 decreases, and unit heat is transferred to the printing material 16 in the adhesion cavity 15 through the inhibiting layer 26 only by the heat flow 36.

[0036] Figure 3C shows that the printing material 16 directly adjacent to the wall 23 begins to evaporate. The evaporated printing material 16 partially escapes through the periphery of the pocket of printing material 16, as indicated by the flow arrow 39. However, the increase in pressure, indicated by arrow 40, pushes the pocket of printing material 16 downward from the adhesion cavity 15. Figure 3D illustrates this process, where the printing material 16 begins to form droplets 20 as it accelerates toward the substrate surface 6.

[0037] Figures 4A and 4B illustrate what can occur when the inhibitory layer 26 is absent, leading to suboptimal or poor print quality experienced with other (LIFT) deposition techniques. In Figure 4A, the low temperature of the sidewall 23 causes the printing material 16 to peel off only from a portion of the sidewall 23. This results in oblique extrusion of the droplet 20. In this case, a portion of the printing material 16 does not hit the target position on the substrate surface 6. In Figure 5A, the uneven pressure distribution within the droplet causes the droplet 20 to begin vibrating (see 45 and 46). This, too, can result in tilted extrusion and other undesirable print effects.

[0038] The results of the adhesion method of the present invention are shown in Figures 5A and 5B. Figure 5A shows the results of the adhesion method of the present invention. In this figure, very regularly spaced, clear and sharp printed areas 55 can be seen. A comparative test was conducted using an apparatus without the multilayer release stack 18 of the present invention. It is clear that the printing material 16 spreads across the entire surface, making it impossible to distinguish the clear printed areas.

[0039] The present invention has been described in relation to several specific embodiments. The embodiments shown in the drawings and described herein are for illustrative purposes only and are not intended to limit the present invention in any way. The operation and structure of the present invention are considered to be evident from the foregoing description and the accompanying drawings. It will be apparent to those skilled in the art that the present invention is not limited to the embodiments described herein, is modifiable, and should be considered within the scope of the appended claims. Furthermore, kinematic inversion is also essentially disclosed and is considered to be within the scope of the present invention. Moreover, any of the components and elements of the various embodiments disclosed may be incorporated or combined in other embodiments without departing from the scope of the present invention as defined in the claims, if deemed necessary, desirable, or preferred.

[0040] In the claims, no reference numeral should be construed as limiting to the claims. The terms “comprising” and “including” as used herein or in the appended claims should not be construed as exclusive or exhaustive, but rather as comprehensive. Accordingly, the expression “comprising” as used herein does not preclude the existence of other elements or steps in addition to those described in the claims. Expressions such as “consisting of” should, when used herein or in the appended claims, be construed as comprehensive, meaning “consisting of at least one,” rather than as an exhaustive enumeration. Furthermore, the words “a” and “an” should not be construed as limiting to “only one,” but are used to mean “at least one,” and do not preclude plural. Features not specifically or expressly described or claimed may be additionally included in the structure of the invention within the scope of the invention. The claimed or disclosed apparatus or parts thereof may be combined with each other or separated into further parts without departing from the claimed invention, unless otherwise stated. Expressions such as "means for..." should be interpreted as "components configured to..." or "members constructed to...", and should be understood to include equivalents of the disclosed structures. The use of expressions such as "important," "preferred," and "particularly preferred" is not intended to limit the present invention. Additions, deletions, and modifications within the scope of those skilled in the art can generally be made without departing from the spirit and scope of the present invention as defined by the claims. The present invention can be carried out in ways other than those specifically described herein and is limited only by the appended claims.

Claims

1. A device for attaching printing material to a substrate, The present invention comprises a light-transmitting plate having a first surface and a second surface opposite to the first surface, wherein the first surface provides a light-receiving surface for receiving light emission signals, and the second surface includes at least one adhesion cavity configured to hold the printing material before the printing material is attached, and the first surface is configured to cooperate with a light source to receive the light emission signals. The at least one adhesion cavity includes one or more walls that form an interface between the at least one adhesion cavity and the light-transmitting plate, and the one or more walls include a multilayer release stack. The multilayer release stack includes a light-absorbing layer and an inhibitory layer, wherein the light-absorbing layer is adjacent to the light-transmitting plate and configured to convert light energy from the light emission signal into heat, and the inhibitory layer is located between the light-absorbing layer and the inside of the at least one adhesion cavity. The inhibiting layer comprises one or more heat-shielding layers, and the light-absorbing layer has a first thermal conductivity greater than the further thermal conductivity of the one or more heat-shielding layers, thereby enabling lateral heat transfer within the light-absorbing layer and uniformly distributing the heat across the light-absorbing layer when heat is transferred to the printing material in the at least one adhesion cavity through the inhibiting layer before the printing material is deposited. Device.

2. The apparatus according to claim 1, wherein the light source is a collimated light source for receiving the light emission signal as a collimated light emission signal.

3. The apparatus according to claim 1 or 2, further comprising a light source or configured to cooperate with a light source, wherein the light source is a pulsed laser light source capable of receiving the light emission signal as a limited-time light pulse.

4. The apparatus according to any one of claims 1 to 3, wherein the inhibiting layer has a second thermal conductivity, the second thermal conductivity is determined by the further thermal conductivity of one or more heat-shielding layers, and the first thermal conductivity of the light-absorbing layer is greater than the second thermal conductivity of the inhibiting layer.

5. The apparatus according to claim 4, wherein the inhibiting layer has a thickness that depends on the first and second thermal conductivity in order to enable the homogenization of the amount of heat.

6. The apparatus according to claim 4 or 5, wherein the light-absorbing layer has a thickness that depends on the first and second thermal conductivity in order to enable the homogenization of the amount of heat.

7. The apparatus according to any one of claims 1 to 6, wherein the inhibiting layer includes a plurality of heat shielding layers.

8. The apparatus according to claim 7, wherein the second thermal conductivity of the inhibiting layer is provided by the combined thermal conductivity of the further thermal conductivity of the plurality of heat-shielding layers forming the inhibiting layer.

9. The apparatus according to any one of claims 1 to 8, wherein the light-absorbing layer is provided by a material layer made of a first material, and the first material includes at least one of a metal or an alloy.

10. The apparatus according to any one of claims 1 to 9, wherein at least one of the one or more heat-shielding layers includes or is provided by a material layer made of a second material, and the second material includes at least one of ceramic, polymer, or composite layer.

11. The material absorption layer contains a molybdenum-chromium alloy, or At least one of the one or more heat-shielding layers contains silicon nitride. The apparatus according to any one of claims 1 to 10, wherein at least one of the above.

12. A method for depositing dots of a printing material onto a substrate using an apparatus according to any one or more of claims 1 to 11, wherein the apparatus includes a light-transmitting plate having a first surface and a second surface opposite to the first surface, the first surface providing a light-receiving surface for receiving light emission signals, and the second surface including at least one deposition cavity configured to hold the printing material before deposition, the method is: Filling the at least one adhesion cavity with the printing material, and To selectively irradiate at least a portion of the light-receiving surface with the light emission signal, thereby transmitting the light emission signal to the at least one adhesion cavity via the light-transmitting plate, and causing the printing material to adhere to the substrate, Includes, The light emission signal is transmitted to the at least one adhesion cavity through a multilayer release stack including a light absorption layer and an inhibitory layer, the light absorption layer converts the light energy from the light emission signal into heat, and before the adhesion of the printing material, the heat is conducted to the printing material in the at least one adhesion cavity through the inhibitory layer, enabling lateral heat transfer within the light absorption layer and reducing the conduction of the heat from the light absorption layer to the at least one adhesion cavity in order to uniformly distribute the heat across the light absorption layer. method.

13. The method according to claim 12, wherein the light emission signal is a collimated light emission signal.

14. The method according to claim 12 or 13, wherein the apparatus further includes a light source or is configured to cooperate with a light source, the light source being a pulsed laser light source capable of receiving the light emission signal as a limited-time light pulse.

15. The method according to any one of claims 12 to 14, wherein the printing material is at least one of an interconnecting material, solder paste, adhesive, resin, ink, or polymer for use on the substrate.

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