Controlled Deposition of Functional Materials onto the Target Surface

Abstract

The present disclosure provides a plate (1) comprising a functional material (2) to be deposited onto a target surface (51) using monochromatic photon radiation (R3) having a wavelength (λ R3 ). The plate comprises a substrate (10) having a first surface (11) directed towards the target surface and a second surface (12) receiving the monochromatic photon radiation. The first surface (11) is patterned to have one or more recessed regions (111) which have a dielectric coating (4) and are filled with the functional material. The dielectric coating (4) comprises a series of dielectric coating sub-layers (41, 42, 43) with alternating refractive indices. The dielectric coating (4) has a relatively high reflectivity for the monochromatic radiation (R3) incident perpendicular to the dielectric coating (4) compared to the reflectivity for the monochromatic radiation (R3) incident at an angle of 45 degrees to the dielectric coating (4). Thereby, shear forces are reduced without requiring high alignment accuracy. The present application also provides a deposition apparatus comprising the plate and a method involving the plate.

Description

Technical Field

[0001] The present application relates to a method for controllably depositing a functional material onto the surface of a target.

[0002] The present application also relates to a plate including a functional material to be deposited onto the surface of a target.

[0003] The present application also relates to a deposition apparatus including such a plate. Background Art

[0004] According to one method, the functional material to be deposited is provided as a continuous layer on a first side of a substrate, and the layer is locally ablated by a laser beam guided through the substrate. Examples thereof are US 2009 / 061112 A1, EP 2 924 718 A1, EP 2 843 079 A1, US 6 177 151 B1.

[0005] According to another method, the functional material to be deposited does not exist as a continuous layer, but exists in a recessed area of a source substrate. A method for controllably depositing a functional material onto the surface of a target according to this method is known from US2017268100. According to the method disclosed therein, a light-transmissive plate is provided, which has a first surface with one or more holes and a second surface opposite the first surface. After coating the first surface with a thin layer of a light-absorbing material, the holes are filled with the functional material. Then the plate is irradiated with pulsed light from the second surface to induce heat in the holes and thereby induce gas to transfer the functional material from the holes to a receiving substrate located near the plate. In this process, the heat flux around the holes will determine the ejection mode of the functional material.

[0006] As Figure 1 schematically shown, the side walls of the holes 111 are generally inclined with respect to the normal direction of the plate. As Figure 1AAs shown, the power density (heat flux) of the light calculated for the sidewall surface is proportional to the cosine of the angle of the sidewall relative to the bottom of the hole. Thus, when in a known method, a focused or collimated laser beam irradiates the hole from the second surface, the sidewalls of the hole will have a lower power density due to the higher angle of incidence. For example, when the sidewall is inclined 70° relative to the bottom, the power density and the consequent heat flux in the sidewall plane are almost 3 times lower compared to the power density at the bottom of the hole. This means that the heat induction at the hole sidewalls is significantly less than that at the bottom of the hole. As a result, the pressure applied to the functional material has a rather uneven distribution, such that the functional material will be subjected to significant shear forces during the transfer process, especially when using a high-viscosity functional material. Although beam shaping is an option for controlling the sidewall heat flux, it becomes more difficult for small spot sizes. Aligning a shaped beam to a small hole also requires a high-precision system. If the size and shape of the holes are different, this method becomes even more complex. In this case, it is necessary to dynamically adjust the beam shape to fit the shape of the hole being targeted. Summary of the Invention

[0007] An object of the present application is to provide an improved method in which shear forces are alleviated without the need for high alignment accuracy. Accordingly, a method as claimed in claim 1 is provided.

[0008] Another object of the present application is to provide an improved plate for the improved method. Accordingly, a plate as claimed in claim 8 is provided.

[0009] Yet another object of the present application is to provide an improved deposition device in which shear forces are alleviated without the need for high alignment accuracy. Accordingly, a deposition device as claimed in claim 15 is provided.

[0010] The improved method of controllably depositing a functional material onto a target surface using monochromatic radiation having a wavelength as claimed in claim 1 comprises the following steps.

[0011] Providing a transparent carrier plate having a substrate, the substrate having a first surface and a second surface opposite to each other. Wherein, one or more recessed areas are provided on the first surface of the substrate. The substrate can be made of any transparent material such as glass or silicon oxide, and one or more recessed areas can be provided therein by any method such as by etching.

[0012] A dielectric coating is deposited on the first surface. Subsequently, a plurality of dielectric coatings are deposited in subsequent steps, wherein the refractive index of each subsequent dielectric coating sub-layer is different from that of the prior dielectric coating sub-layer. That is, at this stage, dielectric coating sub-layers with a lower refractive index and dielectric coating sub-layers with a higher refractive index are deposited alternately. The dielectric coating sub-layers are deposited in a conformal manner with the first surface of the substrate provided with one or more recessed regions, such that the thickness of the dielectric coating sub-layer measured in the direction of the local surface normal is substantially uniform. For practical purposes, the dielectric coating is deposited on the entire first surface. However, this is not necessary. It is sufficient for the dielectric coating to be present at the first surface (including their bottoms and sidewalls) within one or more holes. These thin layers are typically deposited using chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques, which have a well-defined thickness consistent with the surface.

[0013] The thickness of the dielectric (sub)layer is in a range such that the dielectric coating has a relatively high reflectivity for the monochromatic radiation incident perpendicular to the dielectric coating compared to the reflectivity for the monochromatic radiation incident at a 45-degree angle to the dielectric coating. In an embodiment, the thickness of the dielectric coating sub-layer is 0.05 to 0.15 times the wavelength of the monochromatic photon radiation. Thereby, the risk of damage due to thermal stress is reduced. Also for this purpose, it is preferred that the absorption of the monochromatic radiation in the dielectric coating is as low as possible, for example less than 10%, more preferably less than 5%, and still more preferably less than 2%.

[0014] One or more recessed regions are filled with a functional material after the deposition of the dielectric coating. The filling can occur directly after the deposition of the dielectric coating, but other process steps can also be selected for intervention. The dielectric coating can be provided with a protective layer, such as a scratch-resistant layer, for example.

[0015] In use, the transparent carrier plate is located between the monochromatic radiation source and the target surface of the target. Thus, the plate faces the target surface with its first surface.

[0016] Then the monochromatic radiation is directed to the second surface of the plate. The monochromatic radiation has an intensity and duration that cause the functional material to be transferred from one or more recessed regions to the target surface. The monochromatic radiation entering the bottom of the hole transfers the dielectric coating in at least a substantially orthogonal direction. Since the dielectric coating has a high reflectivity for the monochromatic radiation in this direction, its intensity is reduced. The monochromatic radiation entering the sidewalls of the hole transfers the dielectric coating at an angle substantially deviating from at least a substantially orthogonal direction. The dielectric coating has a reduced reflectivity for the monochromatic radiation incident at this deflection angle, such that most of it transmits through the coating. Thereby, a more uniform distribution of the heat flux is achieved, thus reducing the shear force acting on the functional material to be transferred and deposited.

[0017] In the absence of shear forces, the functional material can be transferred with extremely high viscosities. The advantage of this is that the functional material does not spread upon impact, and high-resolution structures with a high aspect ratio are possible. This also enables the transfer process to be carried out at a large distance between the first surface of the plate and the target surface. The larger the transfer gap, the easier it is to implement this technique because the machine tolerance requirements are not high. In addition, a larger transfer gap facilitates printing on uneven surfaces, such as on rough or 3D surfaces. Therefore, this technique is also suitable for 3D printing of electrical interconnections. For example, the viscosity is in the range of 100 Pa.s to 1000 Pa.s.

[0018] It is sufficient for the monochromatic radiation beam to be substantially uniform in the environment of the hole. Thus, the beam does not have to be precisely shaped and aligned with the walls according to the recessed areas. In some embodiments, the monochromatic radiation source is an excimer laser. In other embodiments, the monochromatic radiation source is a scanning laser. In some of these other embodiments, the monochromatic photon radiation is directed to the second surface of the plate through a telecentric lens to ensure that the angle of incidence is equal over the area covered by the monochromatic radiation. It should be noted that if the monochromatic radiation is scanned at a substantially constant speed in the scanning direction and the integral of the beam intensity in the scanning direction is substantially constant within the area of the hole in a direction transverse to the scanning direction, then a substantially uniform exposure is achieved using the monochromatic radiation. Typically, the monochromatic radiation is provided as a large-area light spot while illuminating the entire pattern using an excimer laser. Thus, no scanning is required. For example, a laser spot size of 1x1 to 10x10 mm 2 (larger than the entire pattern itself) transfers the high-resolution interconnect pattern in one go. In this case, no pulse overlap is required.

[0019] In some embodiments, after the step of depositing the dielectric coating and before the step of filling one or more recessed areas with the functional material, a photon radiation absorption layer is deposited. This enables the monochromatic photon radiation transmitted through the dielectric coating to be very effectively converted into heat. This is particularly useful if the functional material to be deposited has a relatively high reflectivity or transmittance to the monochromatic photon radiation. In some of these embodiments, the material of the photon radiation absorption layer evaporates upon absorption of the monochromatic photon radiation and thus contributes to or causes the development of a vapor pressure that expels the functional material from the recessed areas. In other embodiments, a dedicated material to be evaporated can be provided in the recessed areas.

[0020] In some embodiments, a non-recessed portion of the first surface of the plate is provided with a reflective coating that substantially reflects monochromatic radiation. This achieves that when a monochromatic photon radiation beam extends beyond the boundary of the recessed region, functional material (if any) present outside the recessed region does not accidentally deposit on the target surface. Functional material may accidentally be present as a residue outside the recessed region. It may also be desirable to provide functional material over the entire first surface of the plate to simplify the manufacturing process of the plate. In terms of manufacturing a printed plate with increased reflectivity outside the recessed region, a different mirror stack is required compared to inside the recessed region. The simplest way to achieve this is to add a coating with one or more coating sub-layers before forming the recessed region in the plate so that alignment is not required during the manufacturing process. The added coating should increase reflectivity after the dielectric coating is deposited. That is, provide a uniform heat flux distribution on the inner wall of the recessed region.

[0021] As is apparent from the foregoing, the improved plate suitable for the improved deposition process includes functional material to be deposited on the target surface using monochromatic photon radiation having a wavelength. The improved plate includes a substrate having a first surface directed towards the target surface and a second surface that receives the monochromatic photon radiation. The first surface of the plate is patterned to have one or more recessed regions having a dielectric coating and filled with functional material, wherein the dielectric coating includes a series of dielectric coating sub-layers with alternating refractive indices. The dielectric coating has a relatively high reflectivity for monochromatic radiation incident perpendicularly to the dielectric coating compared to the reflectivity of the monochromatic radiation incident at a 45-degree angle to the dielectric coating. As described above, it is sufficient for the dielectric coating to extend over the portion of the first surface defined by the bottom and sidewalls of the recessed region, but the dielectric coating may additionally extend outside the recessed region, for example, to cover the entire first surface area of the plate.

[0022] In an embodiment, the plate is provided with a gray-scale mask at its second surface to control the heat flux of the monochromatic photon radiation. In some instances of these embodiments, the gray-scale mask cooperates with the dielectric coating at the second surface of the plate to provide at least a substantially uniform heat flux transfer at the inner surface of one or more recessed regions. In this way, an additional degree of freedom can be obtained to control the transferred heat flux. For example, on a larger scale, the gray-scale mask can be used to control the release time (different heat fluxes) of certain patterns. For example, when transferring a line, it can be used to provide a reduced or increased heat flux at the end of the line to control how the functional material is ejected.

[0023] In other instances of these embodiments, a gray-scale mask is provided to inhibit the transfer of the radiation outside of these regions. In other instances of these embodiments, the gray-scale mask combines these functions. The gray-scale mask can control the heat flux by absorbing and / or reflecting the radiation according to a spatial pattern. It should be noted that other embodiments are conceivable, in which the gray-scale mask is provided as a separate element that is located between the radiation source and the plate. However, it is advantageous for the gray-scale mask to be integrated with the plate, thereby avoiding separate positioning and alignment steps.

[0024] It is further advantageous to integrate the gray-scale mask with the plate because it enables control of the heat flux at a finer level of detail, for example, at a resolution of less than 10 micrometers. For very precise additional heat flux control using a gray-scale mask, it is desirable to provide the gray-scale mask on the same side of the substrate as the dielectric coating (e.g., between the substrate and the dielectric coating).

[0025] In addition to the improved plate, the improved deposition apparatus further includes the following elements.

[0026] A holder for supporting the target, wherein the target surface faces the first surface of the plate. The target surface is used to receive the functional material.

[0027] A monochromatic photon radiation source is provided to generate monochromatic photon radiation that will be directed towards the second surface of the plate.

[0028] A controller causes the monochromatic radiation source to generate monochromatic photon radiation at an intensity and duration that causes the transfer of the functional material from one or more recessed regions to the target surface.

[0029] In some embodiments, the monochromatic photon radiation source is an excimer laser that generates a beam with a uniform intensity distribution. In other embodiments, a scanning laser is used to generate the monochromatic radiation. In some of these other embodiments, the monochromatic radiation is directed to the second surface of the plate through a telecentric lens to ensure equal incident angles over the area covered by the monochromatic radiation. In one embodiment, the controller is further configured to control the movement of the scanning path of the scanning laser. Alternatively or additionally, the controller can control the position of the holder for carrying the target. Description of the Drawings

[0030] These and other aspects are described in more detail with reference to the accompanying drawings, in which

[0031] Figure 1 and Figure 1A schematically shows the stages in a prior art deposition process;

[0032] Figure 2 shows an embodiment of a deposition apparatus including a plate as claimed herein;

[0033] Figure 3A and Figure 3B It explains various aspects of the board;

[0034] Figure 4 schematically shows the normalized transferred heat flux as a function of the wall angle in a first embodiment of the plate;

[0035] Figure 5 schematically shows the normalized transferred heat flux as a function of the wall angle in a second embodiment of the plate;

[0036] Figure 6 Another embodiment of a deposition apparatus comprising a plate as claimed herein is shown;

[0037] Figure 7 Methods of implementing the method as claimed herein are shown;

[0038] Figure 8 Schematically illustrates exemplary aspects of the method;

[0039] Figures 9A to 9C An alternative embodiment of a plate as claimed herein is shown.

[0040] Detailed description of implementation plan

[0041] Figure 2 Schematic diagram of the use of a wave with wavelength λ R3 A deposition device that controllably deposits the functional material 2 onto the target surface 51 of the target material 5 using monochromatic radiation R3. Figure 2 The deposition device includes a carrier plate 1, a bracket 7 for supporting a target material 5, a monochromatic photon radiation source 3, and a controller 8 for controlling the monochromatic radiation source 3.

[0042] like Figure 2 As shown schematically, the carrier 1 has a substrate 10 having a first surface 11 directed toward the target surface 51 and a second surface 12 receiving the monochromatic photon radiation R3. The first surface 11 is patterned to have one or more recessed areas 111. Figure 2 In the example shown, only one recessed area 111 is shown, but in practice, the carrier 1 may have multiple recessed areas. The recessed area may be of any type, such as a circular hole, a curved or straight groove, etc. The recessed area may, for example, have a width of 10 micrometers or less, but recessed areas of larger sizes may also be considered depending on the application. Figure 2 In the example shown, the entire first surface 11 is provided with a dielectric coating 4. Alternatively, the dielectric coating 4 may be provided only in portions of the first surface 11 defined by the recessed regions 111 and not present outside these regions. The recessed regions 111 are filled with the functional material 2 to be deposited on the target. Figure 2Further schematically shown, the dielectric coating 4 includes a series of dielectric coating sub-layers 41, 42, 43 with alternating refractive indices. The dielectric coating sub-layers 41, 42, 43 are applied with a uniform thickness such that the dielectric coating 4 has a relatively high reflectivity for monochromatic radiation R3B incident on it in the vertical direction, and a relatively low reflectivity for monochromatic radiation R3S incident on it in a direction deviating from the vertical direction, i.e., at an angle of 45 degrees.

[0043] During operation of the deposition apparatus, the controller 8 causes the monochromatic radiation source 3 to emit monochromatic photon radiation R3 having an intensity and duration that cause the functional material 2 to be transferred from one or more recessed regions 111 to the target surface 51. The monochromatic radiation source 3 directs the monochromatic radiation R3 towards the second surface 12 of the carrier plate 1. For this purpose, the monochromatic radiation source 3 may include a laser, such as an excimer laser or a scanning laser, and optionally other optical components, such as a telecentric lens.

[0044] As Figure 2 Schematically shown, for the monochromatic radiation R3B directed towards the bottom 111B of the recessed region 111, it is incident on the dielectric coating 4 in the vertical direction such that a relatively large portion is reflected. In contrast, the monochromatic radiation R3S directed towards the sidewall 111S of the recessed region 111 is incident on the dielectric coating 4 in a direction deviating from the vertical direction, so that only a relatively small portion of it is reflected. Therefore, compared with the case where the dielectric coating 4 is absent, the radiation intensity at the bottom 111B of the recessed region 111 is reduced. As a result, the difference in the heat fluxes generated near the sidewall 111S and the bottom 111B is reduced.

[0045] The first example is shown in more detail in Figure 3A 、 Figure 3B wherein, Figure 3A shows a part of the bottom 111B of the recessed region 111, and Figure 3B shows a part of the sidewall 111S of the recessed region 111. In the example shown, the substrate 10 of the plate is silica, and the dielectric coating 4 is provided with a first high refractive index (n = 2.4) TiO 2 layer 41 with a thickness of 40 nm, a first low refractive index (n = 1.45) SiO 2 layer 42 with a thickness of 40 nm, and a second high refractive index TiO2 layer 43 with a thickness of 40 nm. An Al2O3 protective coating sub-layer 45 with a thickness of 40 nm is also provided. The refractive index of the latter is n = 1.75.

[0046] It is noted that in a dielectric mirror, the thickness of each sub-layer multiplied by its refractive index is typically one quarter of the wavelength of the radiation to be reflected, so that the high refractive index layers are thinner than the layers with a lower refractive index. In the present application, it is not necessary for the dielectric coating to reflect all of the radiation, but it is sufficient that the radiation directed towards the bottom of the recessed portion is attenuated to such an extent that a substantially uniform distribution of the transmitted heat flux on the inner surface of the recessed area is achieved. Suitable coatings meeting this requirement can be selected using simulation without undue effort. For example, starting with the following inputs, the wavelength λ of the monochromatic radiation used R3 , the tilt angle of the walls of the groove element, the plurality of dielectric sub-layers in the dielectric coating, and the mutually different dielectric materials selected for these sub-layers, the thicknesses can be varied in the simulation to determine the thicknesses that achieve the desired attenuation. It can be assumed in the simulation that the thicknesses of the sub-layers are equal, or that the layer thicknesses of the high refractive index layers and the low refractive index layers have a fixed thickness ratio to each other. Thus, only one parameter needs to be varied in the simulation. The simulator available at https: / / www.filmetrics.com / reflectance-calculator is suitable for this purpose.

[0047] At each of the interfaces 10-41, 41-42, 42-43, 43-45 and 45, reflections occur, and these reflections reinforce or cancel each other out depending on the path length differences. The path length through each sub-layer is the product of the layer thickness (d) and its refractive index (n).

[0048] According to the following relationship, the reflection intensity at the interfaces of successive sub-layers depends on their refractive indices (n o , n s ).

[0049]

[0050] The extent to which the reflections cancel each other out depends on their phase difference.

[0051] In one example, the wavelength λ of the monochromatic radiation source used R3 is 532 nm. Thus, for sub-layers 41, 42, 43, 45, the two-way optical path length (*λ R3 ) of the radiation incident in the direction of the surface normal is expressed as a fraction of the wavelength as follows:

[0052] layer material n.d <![CDATA[*λ R3 > 41,43 TiO2 (n = 2.4) 96 0.36 42 SiO2 (n = 1.45) 58 0.22 45 Al2O3 (n = 1.75) 70 0.26

[0053] At the center of the recessed area, the angle of incidence of the light is transverse to the plane of the layer. The various partial reflections are out of phase but not completely out of phase, so that a part of the radiation R3B is reflected and does not reach the bottom 111B of the recessed area 111.

[0054] At Figure 3BIn the case of [description], it is shown that the radiation R3S points to the side wall 111S of the recessed area 111, and the path length increases because the radiation R3S has a direction deviating from the normal direction of the coating 4. Therefore, partial reflection occurs at the layer interface to a greater extent out of phase, so that a relatively small part of the radiation R3S is reflected. As a result, a larger part can reach the side wall 111S of the recessed area 111.

[0055] Figure 4 The relationship between the normalized heat flux (normalized power density) and the beam incident angle is shown. In this example, when the angle increases from 0 degrees to 45 degrees, the normalized heat flux gradually increases from about 1 to 1.8, and when the angle is further decreased to 90 degrees, the normalized heat flux decreases to 0. For an angle of 70 degrees, corresponding to the side wall angle of 111S, the normalized heat flux is approximately equal to 1, so that a substantially uniform heat flux is achieved within the recessed area 111. It should be noted that the heat flux passing through the surface is defined as the power density in the direction of the surface normal (W / m 2 ). The normalized heat flux is a dimensionless value obtained by dividing the heat flux at a specific angle by the heat flux at an angle of 0. In some cases, it may be desirable that the heat flux through the side wall of the recessed area is slightly higher (e.g., about 5% or 10%) than the heat flux through the bottom, so that the side releases just before the bottom. Therefore, the risk of shear force occurrence can be further reduced.

[0056] In another example, the wavelength λ of the monochromatic radiation source used R3 is 308 nm, and the dielectric coating 4 is provided with a first high refractive index (n = 2.1) HfO2 layer 41 with a thickness of 38 nm, a first low refractive index (n = 1.45) SiO2 layer 42 with a thickness of 38 nm, and a second high refractive index HfO2 layer 43 with a thickness of 38 nm. An Al2O3 protective coating 45 with a thickness of 25 nm is also provided. The refractive index of the latter is n = 1.75.

[0057] layer material n.d <![CDATA[*λ R3 > 41,43 HfO2 (n = 2.1) 55 0.36 42 SiO2 (n = 1.45) 80 0.51 45 Al2O3 (n = 1.75) 44 0.28

[0058] Figure 5 The normalized heat flux of this example is shown as a function of the incident angle. The dependence of the normalized heat flux on the incident angle is the same in nature as that of the previous example, but there are differences in quantity. In the case of angles in the range of 0 to about 65 degrees, the difference between the normalized heat flux and the reference value 1 does not exceed about 10%. Therefore, recessed areas 111 with various side wall angles within this angle range can be provided in the carrier plate, and they all have a substantially uniform distribution of heat flux on their bottom walls and side walls.

[0059] Figure 6 An alternative embodiment of the claimed deposition device is shown. Among them, [description] Figure 2The components corresponding to the components in [reference] have the same reference signs. As an additional feature, a reflective coating 6 is provided on the non-recessed portion of the first surface 11 of the carrier plate, such as a reflective metal coating or another dielectric coating 6 that substantially reflects (R3R) monochromatic radiation R3. The dielectric coating 4 extending over the additional dielectric coating 6 can thereby cooperate with the latter. This is because the dielectric coating 4 has been designed to partially reflect the incident radiation perpendicular to the surface. The additional dielectric coating 6 below the dielectric coating 4 provides an additional dielectric coating sublayer that further enhances the reflectivity outside the recessed area.

[0060] Thus, any functional material 2” present in these areas is prevented from being transferred to the target surface 51, even when the monochromatic radiation R3 is directed onto the target surface 51. The reflective coating 6 does not have to completely reflect the radiation R3. It is sufficient that the intensity of the monochromatic radiation R3 is sufficiently reduced to avoid transfer.

[0061] In Figure 6 the illustrated embodiment, the recessed area 111 is further provided with a photon radiation absorption layer 9 between the dielectric coating 4 and the functional material 2. Thereby, the photon radiation is very effectively converted into heat, regardless of the type of functional material 2 used.

[0062] Figure 7 A method for controllably depositing a functional material onto a target surface using monochromatic radiation having a wavelength is schematically illustrated. The method includes step S1, in which a transparent carrier plate is provided with a substrate having a first surface and a second surface opposite each other, thereby providing one or more recessed areas for the first surface. In an embodiment, step S1 includes a first sub-step S1A and a second sub-step S1B. In the first sub-step S1A, a transparent carrier plate is provided, for example, a carrier plate made of glass or silicon oxide. In the second sub-step S1B, the first surface is provided with one or more recessed areas.

[0063] In Figure 7 the embodiment, an additional sub-step S1C is performed. In this sub-step S1C, a reflective coating is deposited on the first surface, which substantially reflects the monochromatic radiation incident perpendicular to the reflective coating. Sub-step S1C includes, for example, depositing a reflective metal coating, such as a silver layer. However, preferably, a series of sub-sub-steps are used to apply a dielectric coating sublayer, where the dielectric coating is then deposited to form a dielectric mirror that (optionally in combination with the dielectric coating 4) substantially reflects the perpendicularly incident monochromatic radiation of the said wavelength. When using a dielectric mirror, the amount of heat absorption is relatively small compared to using a metal coating, thereby reducing the risk of damage. In Figure 7 the example, sub-step S1C is performed before providing the first surface with one or more recessed areas in step S1B. As a result, the same is obtained as in Figure 6The plate used in the deposition apparatus, wherein the non-recessed portion of the first surface 11 of plate 1 is provided with a reflective coating 6 that substantially reflects the monochromatic radiation R3. As referenced Figure 6 As discussed, therefore, the risk of inadvertent transfer of material outside the recessed portion is reduced. Since in this embodiment of the method, sub-step S1B is carried out after sub-step S1C, there is no need to precisely align the deposition process in sub-step S1C. In sub-step S1C, the dielectric coating 6 or other reflective coating can simply be deposited on the entire first surface of the plate, and in sub-step S1B, the coating is locally removed in the portion of the first surface occupied by the recessed portion. However, it is possible to consider carrying out sub-step S1C after sub-step S1B, provided that care is taken that the first surface occupied by the recessed portion remains free of material for the reflective coating.

[0064] In step S2 of the method, a dielectric coating is deposited. Step S2 includes a series of sub-steps, wherein in each subsequent sub-step, a dielectric coating sub-layer having a refractive index different from that of the dielectric coating sub-layer deposited in the previous sub-step is deposited. It is sufficient for the dielectric coating sub-layer obtained thereby to extend within the portion of the first surface defined by one or more recessed regions, but alternatively, the dielectric coating can also extend beyond one or more recessed regions. Generally, the dielectric coating is deposited on the entire surface of the plate, thus avoiding masking and alignment problems.

[0065] The dielectric coating has a relatively high reflectivity for monochromatic radiation incident perpendicularly thereon compared to the reflectivity of the monochromatic radiation incident at an angle of 45 degrees on the dielectric coating.

[0066] In a subsequent step S3, one or more recessed regions are filled with a functional material, for example, copper, aluminum, tungsten, chromium, polysilicon to be deposited. Other materials than metals are also suitable as functional materials. The functional material can be provided, for example, as an ink in which conductive particles are suspended. The rheological properties of the functional material can be modified by additives or solvents, for example to obtain shear thickening, shear thinning, thixotropic, rheological or Bingham plastic behavior. In particular, a donor material having shear thinning behavior is advantageous. A donor material having such behavior has a viscosity that decreases with the shear strain rate. A shear thinning donor material remains as a stable layer on the donor substrate but is relatively easily deformed during deposition. For example, the functional material is a viscous silver nanoparticle ink having a high metal loading.

[0067] It should be noted that further process steps can be carried out before filling one or more recessed areas with the functional material. For example, a photon radiation absorption layer can be deposited after the step of depositing the dielectric coating and before the step of filling one or more recessed areas with the functional material. As described above, this improves the conversion of monochromatic radiation to heat. Alternatively or additionally, an evaporable material can be deposited in one or more recessed areas before filling with the functional material.

[0068] After filling one or more recessed areas with the functional material in step S3, the transparent carrier plate is ready for use in a deposition device, such as Figure 2 or Figure 6 shown.

[0069] Thereby, the transparent carrier plate 1 is located between the monochromatic radiation source 3 and the target surface 51 of the target material, with the first surface 11 facing the target surface 51, such as Figure 2 and Figure 6 shown.

[0070] In operation, the monochromatic radiation R3 of the monochromatic radiation source 3 is directed towards the second surface 12 of the plate 1 in step S4. Thus, the monochromatic radiation R3 has an intensity and duration that cause the functional material 2 to be transferred S5 from one or more recessed areas 111 to the target surface 51. The optimal values of the intensity and duration can be determined by conventional tests of the transmittance of the selected functional material and coating sub-layers. The duration of the thermal radiation is usually very short, for example in microseconds, and usually even shorter, in nanoseconds. In practice, good results with moderate technical requirements can be obtained with a pulse duration of about a few to several tens of nanoseconds. However, in some cases, shorter pulse durations can be applied, such as 10 ps to 500 ps. During the test phase, the intensity can range from relatively low values (e.g., corresponding to an exposure (fluence) of about 0.1 J / cm 2 to relatively high values (e.g., corresponding to an exposure (fluence) of about 1 J / cm 2 to determine for which value or range of values the transfer of the functional material 2 is optimal in terms of deposition accuracy.

[0071] According to one method, the entire second surface 12 of the plate 1 is irradiated with a beam having a uniform power density. In that case, a uniform exposure with an exposure value equal to the product of the power density and the exposure time is achieved.

[0072] According to another method, as Figure 8 shown, a scanning beam is used to scan along the second surface 12 parallel to the axis y in the scanning direction Sy relative to the recessed areas 111 (the grooves shown here as dashed lines) at the first surface at a speed v.

[0073] In this case, the exposure E(x,y) can be determined as:

[0074]

[0075] Where P(.,.) describes the spatial distribution of the light beam R3, and Q() describes how the total beam power varies with time t.

[0076] Figure 8 The footprint 31 when the scanning beam is pulsed during scanning is shown. Previous pulses are represented as dashed circles, such as 31”. As a result of the scanning, if the distance between subsequent pulse regions 31”, 31 is subsequently small, for example, this distance should be less than one-third of the footprint size in the scanning direction, then uniformity of the energy density at the second surface is obtained in the scanning direction. Also in the direction x perpendicular to the scanning direction, the exposure variation may be limited. For example, it may be required that the maximum exposure Emax and the minimum exposure Emin in the range x1 < x < x2 satisfy the following relationship:

[0077]

[0078] This can be achieved with a highly uniform light beam. Alternatively, as Figure 8 shown, a light beam with a footprint extending beyond the boundaries of the recessed region 111 can be applied, and the footprint is sufficiently uniform within these boundaries. When using a pulsed laser, the pulse frequency should be high enough to uniformly heat the functional material, for example, a frequency of 100 kHz or higher. In the case where the timing release is controlled by the scanning speed, a continuous-wave laser can also be used.

[0079] As noted in reference Figure 6 precautions can be taken to reduce the risk of accidental transfer of the functional material due to beam exposure of the plate in the regions outside the recessed region.

[0080] Return Figure 7 , where it is further shown that after the deposition process in steps S4, S5 is completed, the recessed region of the carrier plate can be refilled with the functional material in step S3, so that the carrier plate is ready to be used again. Optionally, before refilling in step S3, the carrier plate, especially its first surface, can be cleaned in an additional step S6.

[0081] Figures 9A to 9C A further embodiment of the transparent carrier plate 1 is shown. Where the components corresponding to the components in Figure 2 and Figure 6 have the same reference numerals. For clarity, the dielectric coating 4 is shown without further details. The dielectric coating 4 at the first surface 11 can, for example, have a stack of dielectric coating sub-layers 41, 42, 43, as Figure 3A , Figure 3B shown in more detail inFigure 3A , Figure 3B , Figure 4 and Figure 5 as described. Other layers may also be provided, such as a protective coating. In Figures 9A to 9C the embodiment shown, the transparent carrier plate 1 is additionally provided with a gray-scale mask 122 to control the heat flux of the monochromatic photon radiation R3.

[0082] In Figure 9A the example shown, the gray-scale mask 122 has a transparent first region 122BS corresponding to the region defined by the recessed region 111. The gray-scale mask 122 has a complementary second opaque region 122O. When the plate 1 is exposed to the radiation R3, the portion of the radiation incident at the transparent first region 122BS is transmitted toward the dielectric coating 4 in the recessed region 111, whereby the heat flux transmitted in the surface of the side wall 111S and the heat flux transmitted in the surface of the bottom wall 111B have substantially the same magnitude.

[0083] In Figure 9B the example shown, the gray-scale mask 122 has a central region 122B corresponding to the surface region of the bottom wall 111B of the groove region 111, a boundary region 122S corresponding to the surface region of the side wall 111S of the groove region 111, and a complementary region 122O. In this example, the gray-scale mask 122 is provided to control the heat flux of the monochromatic photon radiation R3 to cooperate with the dielectric coating 4 to provide at least substantially uniform heat flux transmission at the inner surface of one or more recessed regions 111. Thus, additional degrees of freedom can be obtained. For example, if grooves with side walls having different tilt angles are provided therein, the gray-scale mask 122 can be designed to achieve at least substantially uniform heat flux transmission even if the dielectric coating does not provide proper compensation for the full range of side wall angles. For example, in the case of the plate described with reference to Figure 4 being provided with a coating, in addition to the grooves having a wall angle of 70 degrees, the plate further includes grooves having a wall angle of 45 degrees or 80 degrees. In Figure 9B the example shown, the central region 122B has a transmittance of, for example, 60%, while the boundary region 122S has a transmittance of approximately 100%. In that case, for the grooves with side walls having an angle of 80 degrees, using the coating described with reference to Figure 4 substantially uniform heat flux transmission can be obtained on the inner surface of the grooves. In Figure 9B the example, the transmittance of the complementary region 122O is also approximately 100%.

[0084] In Figure 9C the example shown, the gray-scale mask 122 combines the functions provided in Figure 9A and Figure 9B the examples.

Claims

1. A method for controllably depositing a functional material (2) onto a surface (51) of a target using monochromatic radiation (R3) having a wavelength (λ R3 ), the method Comprising: - Providing a transparent carrier (1) having a substrate (10), the substrate (10) having a first surface (11) and a second surface (12) opposite to each other, wherein one or more recessed regions (111) are provided on the first surface (11); - Depositing a dielectric coating (4) on the first surface (11), the dielectric coating (4) comprising a series of dielectric coating sub-layers (41, 42, 43) with alternating refractive indices, and the dielectric coating (4) having a relatively high reflectivity for the monochromatic radiation (R3) incident perpendicular to the dielectric coating (4) compared to the reflectivity for the monochromatic radiation (R3) incident at a 45-degree angle to the dielectric coating (4); - Filling the one or more recessed regions (111) with the functional material (2); - Positioning the transparent carrier (1) between a monochromatic radiation source (3) and the target surface (51), wherein the first surface (11) faces the target surface (51); - Directing the monochromatic radiation (R3) towards the second surface (12) of the transparent carrier (1), the monochromatic radiation (R3) having an intensity and duration that cause the functional material (2) to transfer from the one or more recessed regions (111) to the target surface (51).

2. The method according to claim 1, wherein the thickness of the dielectric coating sub-layers (41, 42, 43) is from 0.05 times to 0.15 times the wavelength (λ R3 ) of the monochromatic radiation (R3).

3. The method according to claim 1 or 2, further comprising, before providing the one or more recessed regions (111) on the first surface (11), depositing a reflective coating (6) at the first surface (11), the reflective coating (6) substantially reflecting the incident monochromatic radiation (R3).

4. The method according to claim 1, wherein a scanning laser is used to generate the monochromatic radiation (R3).

5. The method according to claim 4, wherein the monochromatic radiation (R3) is directed to the second surface (12) of the transparent carrier (1) via a telecentric lens to ensure equal incident angles over the area covered by the monochromatic radiation (R3).

6. The method according to claim 4, wherein an excimer laser is used to generate the monochromatic radiation (R3).

7. The method according to any one of claims 1, 2 and 4 to 6, further comprising a step of depositing a photon radiation absorption layer (9) after the step of depositing the dielectric coating and before the step of filling the one or more recessed regions (111) with the functional material (2).

8. A transparent carrier (1) comprising a functional material (2) deposited onto a target surface (51) using monochromatic radiation (R3) having a wavelength (λ R3 ). The transparent carrier (1) comprises a substrate (10) having a first surface (11) directed towards the target surface and a second surface (12) receiving the monochromatic radiation (R3), wherein the first surface (11) is patterned to have one or more recessed regions (111) having a dielectric coating (4) and filled with the functional material, wherein the dielectric coating (4) comprises a series of dielectric coating sub-layers (41, 42, 43) with alternating refractive indices, and the dielectric coating (4) has a relatively high reflectivity for the monochromatic radiation (R3) incident perpendicular to the dielectric coating (4) compared to the reflectivity of the monochromatic radiation (R3) incident at a 45-degree angle to the dielectric coating (4).

9. The transparent carrier (1) according to claim 8, wherein the thickness of the dielectric coating sub-layers (41, 42, 43) is from 0.05 times to 0.15 times the wavelength (λ R3 ) of the monochromatic radiation (R3).

10. The transparent carrier (1) according to claim 8, wherein the dielectric coating (4) covers the first surface (11) in a blanket manner.

11. The transparent carrier (1) according to one of claims 8 to 10, wherein, the dielectric coating (4) is covered by a protective layer (45).

12. The transparent carrier (1) according to one of claims 8 to 10, wherein the non-recessed portion of the first surface (11) is provided with a reflective coating (6) that substantially reflects the monochromatic radiation (R3).

13. The transparent carrier (1) according to any one of claims 8 to 10, comprising a photon radiation absorption layer (9) between the dielectric coating (4) and the functional material (2) at least in the one or more recessed regions (111).

14. The transparent carrier (1) according to any one of claims 8 to 10, provided with a gray-scale mask (122) at its second surface (12) to control the heat flux of the monochromatic radiation (R3) in cooperation with the dielectric coating (4), so as to provide at least substantially uniformly transferred heat flux at the inner surface of the one or more recessed regions (111) and / or to inhibit the transfer of the radiation outside these regions.

15. Deposition device comprising: - a transparent carrier (1) according to any one of claims 8 to 14; - a holder (7) for holding a target (5), wherein the target surface (51) faces the first surface (11) of the transparent carrier (1); - a monochromatic radiation source (3) for directing monochromatic radiation (R3) towards the second surface (12) of the transparent carrier (1); - a controller (8), the controller (8) causing the monochromatic radiation source (3) to generate the monochromatic radiation (R3) with an intensity and duration that causes the functional material (2) to be transferred from the one or more recessed regions (111) to the target surface (51).

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