Pattern transfer sheet and method using a release layer and / or paste mixture

Abstract

A pattern transfer sheet and method using a release layer and / or a paste mixture provides a pattern transfer sheet and method for printing paste patterns having a high aspect ratio (e.g., thin gate lines) and for increasing the yield of pattern transfer printing. A trench in the pattern transfer sheet is coated internally with a coating configured to decompose upon irradiation, the trench being configured to be filled with a printing paste and to enable release of the printing paste from the trench onto a receiving substrate upon irradiation by a laser beam. The coating is configured to enhance release of the paste - increasing yield and printing precision. The receiving substrate can be cleaned after paste deposition by removing decomposition products of the coating therefrom. Alternatively or complementarily, a laser-absorbing dye can be mixed into the printing paste to facilitate its release from the trench.

Description

Technical Field

[0001] This invention relates to the field of transfer printing, and more specifically, to improvements in paste release. Background Technology

[0002] U.S. Patent No. 9,616,524 (which is incorporated herein by reference in its entirety) teaches a method of depositing material on a receiving substrate, the method comprising: providing a source substrate having a rear surface and a front surface, the rear surface carrying at least one piece of coating material; providing a receiving substrate adjacent to the source substrate and positioned facing the coating material; and radiating light toward the front surface of the source substrate to remove at least one piece of coating material from the source substrate, and depositing the removed at least one piece as a whole onto the receiving substrate.

[0003] Lossen et al. (2015), Pattern Transfer Printing (PTP TM )for c-Si solar cellmetallization,5 th The Workshop on Metallization for Crystalline Silicon SolarCells, Energy Procedia 67:156-162 (which is incorporated herein by reference in its entirety) teaches pattern transfer printing (PTP). TM As a non-contact printing technology for advanced front-side metallization of c-Si PV solar cells, this technology is based on laser-induced deposition on polymer substrates.

[0004] WIPO Publication No. 2018020479 (which is incorporated herein by reference in its entirety) teaches the application of a conductor to a solar cell by providing a flexible film having a trench pattern formed on a first surface thereon, such that the trenches are filled with a composition comprising conductive particles. Once the film is filled, the grooved first surface of the film is brought into contact with the front and / or rear of the solar cell. Pressure is then applied between the solar cell and the film to adhere the composition filled into the trenches to the solar cell. The film and the solar cell are separated, leaving the composition in the trenches on the surface of the solar cell. The conductive particles in the composition are then sintered or otherwise melted to form a pattern of conductor on the solar cell corresponding to the pattern formed in the film. Summary of the Invention

[0005] The following is a brief overview providing a preliminary understanding of the invention. This overview does not necessarily identify key elements and should not be used to limit the scope of the invention, but is merely intended to introduce the following description.

[0006] One aspect of the invention provides a pattern transfer sheet comprising a plurality of grooves arranged in a specific pattern and configured to be filled with printing paste and to enable the printing paste to be released from the grooves onto a receiving substrate upon irradiation by a laser beam, wherein the interior of the grooves is coated with a coating configured to decompose upon irradiation to enhance the release of the paste.

[0007] One aspect of the present invention provides a pattern transfer method comprising: coating a coating inside a plurality of grooves of a pattern transfer sheet, the grooves being configured to be filled with printing paste, such that the printing paste can be released from the grooves onto a receiving substrate upon irradiation by a laser beam, wherein the coating is configured to decompose upon irradiation to enhance the release of the paste; and optionally cleaning the receiving substrate by removing decomposition products of the coating therefrom.

[0008] One aspect of the invention provides a paste for a pattern transfer process, wherein the paste is filled into a plurality of trenches arranged in a specific pattern in a polymer pattern transfer sheet, and the paste is continuously released from the trenches onto a receiving substrate upon irradiation by a laser beam, wherein: the irradiation is near-infrared (NIR), the paste contains a release material configured to enhance the release of the paste from the trenches, and the release material contains at least one NIR absorbing dye, said NIR absorbing dye comprising at least one of: diimide ion complexes, dithiolene complexes, phthalocyanines, their derivatives, salts and / or combinations thereof.

[0009] One aspect of the invention provides a printing paste comprising, by weight, 50% to 90% silver particles, 1% to 10% solvent, 1% to 5% glass frit, 1% to 5% polymer binder, 1% to 5% additives, and 1% to 7% NIR absorbing dye, wherein the solvent has the following solubility parameters: δD of 14√MPa to 17√MPa, δP of 4√MPa to 11√MPa, and δH of 7√MPa to 11√MPa, and the NIR absorbing dye comprises at least one of the following: diimide ion complexes, dithioene complexes, phthalocyanines, their derivatives or salts, and / or combinations thereof.

[0010] One aspect of the invention provides a printing paste comprising, by weight, 50% to 90% silver particles, 1% to 5% glass frit, 1% to 5% polymer binder, 1% to 5% additives, and 0.1% to 1% NIR absorbing dye, wherein the NIR absorbing dye comprises at least one of the following: diimide ion complexes, dithioene complexes, cyanines, phthalocyanines, their derivatives or salts and / or combinations thereof.

[0011] One aspect of the present invention provides a pattern transfer system in which laser transfer is performed using a disclosed pattern transfer sheet and / or by a disclosed pattern transfer method and / or by a disclosed paste composition.

[0012] One aspect of the invention is the ability to print paste patterns that are narrower and have a higher aspect ratio than currently possible, and / or to use less energy to release the paste.

[0013] These, additional and / or other aspects and / or advantages of the invention are set forth in the following detailed description; can be inferred from the detailed description; and / or may be learned by practice of the invention. Attached Figure Description

[0014] To better understand embodiments of the invention and to illustrate how embodiments of the invention can be implemented, reference will now be made to the accompanying drawings by way of example only, wherein the same reference numerals always indicate corresponding elements or parts.

[0015] In the attached diagram:

[0016] Figure 1 This is a high-level schematic cross-sectional view of a pattern transfer sheet according to some embodiments of the present invention.

[0017] Figure 2A and 2B This is a high-level schematic side view of a pattern transfer process utilizing a release layer according to some embodiments of the present invention.

[0018] Figure 3A and 3B This is a high-level schematic side view of the release layer coating process according to some embodiments of the present invention.

[0019] Figure 4A This is a high-level flowchart illustrating a method for monitoring pattern transfer printing according to some embodiments of the present invention.

[0020] Figure 4B This is a high-level schematic diagram of options for using dyes in methods and in PTP systems according to some embodiments of the present invention.

[0021] Figures 5A to 5C The effects of using a coating on print quality and the amount of residue remaining on the receiving substrate are illustrated according to some embodiments of the invention.

[0022] Figure 6A and 6B The effect of cleaning a substrate by high-temperature heat treatment according to some embodiments of the present invention is shown.

[0023] Figure 7A and7B The ability to produce extremely fine lines using a coating is demonstrated according to some embodiments of the invention.

[0024] Figure 8 Illustrations of grid lines printed with a dye-mixed paste at different parameter values ​​according to some embodiments of the present invention are provided.

[0025] Figure 9 Illustrations of grid lines printed using a dye-mixed paste according to some embodiments of the present invention are provided.

[0026] It should be understood that, for the sake of simplicity and clarity, the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be enlarged relative to others for clarity. Furthermore, where deemed appropriate, reference numerals may be repeated in the figures to indicate corresponding or similar elements. Detailed Implementation

[0027] In the following description, various aspects of the invention are described. Specific constructions and details are set forth for illustrative purposes to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without the specific details presented herein. Furthermore, well-known features may have been omitted or simplified so as not to obscure the invention. Referring specifically to the accompanying drawings, it is emphasized that the details shown are by way of example and are used only for the purpose of illustrative discussion of the invention, and are presented to provide the most useful and readily understood description of what is considered to be the principles and concepts of the invention. In this regard, no attempt is made to show the structural details of the invention in more detail than necessary for a basic understanding of the invention; the description taken in conjunction with the drawings makes it apparent to those skilled in the art how several forms of the invention can be practiced in practice.

[0028] Before explaining at least one embodiment of the invention in detail, it should be understood that the invention is not limited in its application to the details of the construction and the arrangement of components set forth in the following description or shown in the drawings. The invention is applicable to other embodiments that can be practiced or performed in various ways, as well as combinations of the disclosed embodiments. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting.

[0029] Embodiments of the present invention provide efficient and economical methods and mechanisms for performing transfer printing processes, thereby improving the technical field of circuit production. Pattern transfer sheets and methods are provided for printing thin paste patterns (e.g., paste grid lines) with high aspect ratios and for increasing the yield of pattern transfer printing. The grooves in the pattern transfer sheet are coated with a coating configured to decompose upon irradiation, the grooves being configured to be filled with printing paste and enabling the printing paste to be released from the grooves onto a receiving substrate upon irradiation by a laser beam. The coating is configured to enhance paste release—increasing yield and print quality. The receiving substrate can be cleaned after paste deposition by removing the decomposition products of the coating therefrom. Alternatively or complementaryly, laser-absorbing dye can be mixed into the printing paste to promote its release from the grooves.

[0030] Advantageously, the disclosed pattern transfer sheet and method enable the printing of very fine conductive lines with high aspect ratios on PV cells and the printing of raised patterns with high aspect ratios on PCBs, printed resistors and capacitors, and other printed electronic devices. The disclosed embodiments improve the quality of the printed patterns (e.g., help avoid defects), enabling the reduction of feature widths and the increase of the aspect ratio of printed features. Some embodiments also increase the throughput of the PTP system by making the printing process faster.

[0031] In some implementations, the disclosed implementations enable the printing of electrode patterns with a higher aspect ratio and better print quality compared to existing technologies, and improve transfer printing yield and output.

[0032] Figure 1 This is a high-level schematic cross-sectional view of a pattern transfer sheet 100 according to some embodiments of the present invention. The pattern transfer sheet 100 includes a plurality of trenches 110 arranged in a specific pattern (the pattern is not shown and may have any configuration). The trenches 110 are configured to be filled with printing paste 90 and, upon irradiation by a laser beam 80, enable and support the continuous release of the printing paste 90 from the trenches 110 onto a receiving substrate 70. Furthermore, the interior of the trenches 110 is coated with a coating 120 configured to decompose upon irradiation 80 to enhance the release of the paste 90 from the trenches 110. The coating 120 (also referred to as the release layer 120 due to its function) may be a thin layer (e.g., 1 μm to 10 μm thick) deposited on the pattern transfer sheet 100, which serves as the source substrate, or at least deposited into its trenches 110. In some cases, the material of the release layer 120 (represented as the release material) may be mixed with the paste before the paste 90 is filled into the trenches 110. Non-limiting examples of release materials include acetone-based ClearWeld. TM LD920 series and acrylic resins such as Epolin's Spectra 390 TMIn several embodiments, the carrier portion of the pattern transfer sheet 100 may include a stretchable substrate with specific tensile properties, such as a polymer substrate, or the carrier portion of the pattern transfer sheet 100 may include a rigid substrate, such as a glass substrate.

[0033] Coating 120 may comprise organic materials such as NIR absorbing dyes. At least one of the materials used in coating 120 is selected to absorb laser irradiation 80 used in the PTP process (e.g., laser irradiation at a wavelength of 1064 nm). One or more materials may be selected to have maximum absorption at the irradiation wavelength. The release material may be configured to undergo a phase transition, evaporate, and / or ablate upon absorbing laser irradiation energy to generate a thrust that pushes slurry 90 out of trench 110 (without changing the shape of the slurry) and releases slurry 90 onto receiving substrate 70. For example, for irradiation 80 using an Nd:Yag laser (1060 nm to 1085 nm), coating 120 may comprise NIR (near-infrared) absorbing dyes.

[0034] Coating 120 can be used to replace or increase the volatile components of the slurry (e.g., added to evaporate and release slurry 90 upon irradiation). Advantageously, the inventors have discovered that using coating 120 enables the printing of slurry patterns (e.g., slurry grid lines) on the receiving substrate 70 at much higher aspect ratios, such as at least 0.7 and as high as 1 to 2—instead of the prior art's 0.4 to 0.5; and enables the printing of grid lines and / or mesh lines as low as 10 μm wide—instead of the prior art's more than 25 μm to 30 μm wide (see, for example...). Figure 7A and Figure 7B Furthermore, avoiding the use of volatile compounds in paste 90 broadens the range of printable pastes and makes the process less sensitive to paste drying. Additionally, although the release layer 120 is much thinner than the paste, it requires lower laser power to release the paste, and therefore allows printing at higher scanning beam speeds, resulting in higher system throughput. Finally, using the release layer 120 makes the printing process more precise, thus avoiding printing defects such as paste residue and grid line waviness.

[0035] Figure 2A and Figure 2BThis is a high-level schematic side view of a pattern transfer process utilizing a release layer according to some embodiments of the present invention. The trenches 110 in wafer 100 (as a source substrate) can be internally coated by a coating 120 configured to decompose upon irradiation 80 to enhance the release of the slurry 90. The coated trenches filled with slurry are schematically represented by numeral 110A. During the release of the slurry 90, the coating 120 can decompose (schematically represented by numeral 120A) and deposit together with the released slurry (schematically represented by numeral 90A) onto wafer 70 (as a receiving substrate). As a result, wafer 70 may include the released slurry (schematically represented by numeral 90B) and coating residues (and / or decomposition products) (schematically represented by numeral 120B)—an intermediate state represented by numeral 130. Following the pattern transfer process (via PTP system 101), coating residue 120B can be removed from wafer 70, for example, by high-temperature treatment (“e.g., calcination, sintering, and / or drying”) of a metal paste typically used for sintering printing in PV cell manufacturing, or by using irradiation 140 to alter and / or remove residues—to clean the receiving substrate and produce wafer 70 with released paste and free of coating decomposition products and residues (this stage is schematically represented by numeral 75). Irradiation 140 can be the same as, similar to, or different from irradiation 80. In several embodiments, the residue 120B of the released material can be removed using any of the following methods: vacuum-assisted vaporization, blowing, washing, and / or wet cleaning.

[0036] Specifically, the multiple grooves in the pattern transfer film can be arranged in a specific pattern and configured to be filled with printing paste. When irradiated by a laser beam, the printing paste can be activated to be released from the grooves onto the receiving substrate.

[0037] The printing paste layer may contain organic components and a solid phase component of a metal (e.g., silver, copper, tin, or bismuth) that can act as a conductive medium. The organic component can be selected to provide a specific pressure required to overcome the resistance of the printing paste layer separating from the trench. This specific pressure can be achieved, for example, by adjusting the content of the organic component in the printing paste layer and / or the coating within the trench and / or by adjusting the ratio of the solid phase component of the conductive metal medium. For example, in cases where the printing paste layer has high viscosity and high damping characteristics when in contact with the inner wall of the trench, and / or if the content of the solid phase component is high, or if the organic component has strong adhesion, the resistance of the printing paste layer may be relatively large, and the corresponding specific pressure may also be configured to be greater.

[0038] Figure 2A and Figure 2B The pattern transfer method 200 is further illustrated schematically, which is in Figure 4AThe diagram further illustrates that the pattern transfer method 200 includes coating trenches with a coating used as a release layer (step 210), filling the coated trenches with slurry (step 240), releasing the slurry from the trenches by irradiation and decomposition of the release layer (step 250), and cleaning the residues and decomposition products of the release layer on the substrate if necessary (step 260).

[0039] In several embodiments, the coating residue 120B can be removed by any of the following processes: high-temperature decomposition, selective laser vaporization, vacuum-assisted vaporization (lowering the boiling point of the coating residue 120B), blowing, and / or solvent washing. When using a heat-based process to remove the coating residue 120B, the coating material can be selected to have a decomposition temperature and / or boiling temperature that does not affect the deposition of the slurry 90B (e.g., grid lines) and the receiving substrate 70. For example, the coating material can be selected to have a decomposition temperature and / or boiling temperature much lower than the high sintering temperature (approximately 850°C) of the c-Si PV metallization process, or optionally much lower than the curing temperature of the curing slurry (e.g., silver epoxy slurry). For example, the decomposition temperature and / or evaporation temperature of the coating residue 120B can be in the range of 200°C to 300°C. In some embodiments, the same laser irradiation 80 used for releasing the evaporation layer 120 of the slurry 90 can also be used to evaporate and / or decompose the coating residue 120B on the wafer 70. Note that the removal of coating residue 120B can be carried out in a single process step or in two or more process steps (e.g., high-temperature decomposition (e.g., by laser irradiation 80 and / or in any of an oven, drying furnace and / or sintering furnace), followed by low-temperature washing or purging).

[0040] The following non-limiting examples disclose NIR absorbing dyes for use with Nd:Yag laser irradiation. In addition to NIR absorbing dyes, coating 120 may also contain solvents and optional binders, surface agents, and / or viscosity modifiers.

[0041] Non-limiting examples of components for NIR absorbing dyes include diimide ion complexes, dithioene complexes, and / or phthalocyanines. Diimide ion complexes shown may include, for example, an alkyl chain R as one or more residues and a counter-charge ion (not shown), such as 2SbF6. - .

[0042]

[0043] In any disclosed embodiment, further non-limiting examples of the components of the NIR absorbing dye may include any of the following: for example, having an extended [CH=CH]... n Chain-linked cyanine (tetramethylindole(di)-carbonylcyanine) dyes, such as open-chain cyanine (R2N) +=CH[CH=CH] n - NR2), hemicyanine (aryl=N) + =CH[CH=CH] n -NR2), closed-chain anthocyanin (aryl=N) + =CH[CH=CH] n -N = aryl), neutral anthocyanin (R2N) + =CH[CH=CH] n -CN and R2N + =CH[CH=CH] n -CHO), or variants or mixtures thereof; phthalocyanine or naphtholine dyes (containing four isoindole units linked by a nitrogen atom ring) or their metal complexes (e.g., with aluminum or zinc), dithioene metal complexes (having one to three dithioene ligands) (e.g., with nickel), squaraine dyes such as squarylium dye III, quinone analogs, diimide compounds and azo derivatives, and / or any variants, derivatives and / or combinations thereof.

[0044] The solvents contained in the coating formulation may be selected as solvents for dissolving dyes, as well as optional binders and additives, and may include solvents such as acetone, ketones, alcohols, aromatic hydrocarbons and / or glycol ethers.

[0045] The coating formulation may also include a binder to form a coating 120 as a continuous film in the trench 110. The binder comprises a polymer and / or a polymer precursor, such as polyvinyl butyral, ethyl cellulose, and / or derivatives thereof, provided that the binder's decomposition temperature is below the sintering temperature of the slurry (e.g., 800°C for silver paste 90, or for silver paste or other metal pastes or mixtures thereof, such as any one of 850°C, 800°C, 750°C, 700°C, 650°C, 600°C, 550°C, 500°C, 450°C, 400°C, 350°C) or below the curing temperature of the slurry (e.g., 300°C for silver epoxy slurry 90, or for silver epoxy slurry or other metal pastes, such as any one of 300°C, 250°C, 200°C). For example, when the sintering temperature of the slurry is below 800°C, the coating may degrade or decompose. In another embodiment, the coating may degrade or decompose when the slurry curing temperature is below 300°C. Adhesives may also be selected to minimize the amount of coating residue 120B and / or simplify its removal.

[0046] The coating formulation may also contain surface wetting additives selected to stabilize the dispersion of different coating components and / or viscosity modifiers selected to support the application of coating 120 in trench 110. The additives and / or viscosity modifiers are selected to have a decomposition temperature below the sintering temperature or curing temperature of the slurry (depending on the type of slurry), and may also be selected to minimize the amount of coating residue 120B and / or simplify the removal of coating residue 120B.

[0047] In some embodiments, the solid content of coating 120 may be from 10% to 20% by weight to enable a coating 120 with a thickness of 1 μm to 10 μm to be achieved within a trench 110 with a depth of 20 μm to 30 μm.

[0048] In some embodiments, the coating formulation or any component thereof, such as NIR absorbing dye, may be mixed into paste 90 to enhance release or possibly at least partially replace coating 120 (e.g., in certain areas of pattern transfer sheet 100). Therefore, in addition to commercially available printing pastes (e.g., from Heraeus...) TM SOL9651B TM In addition to the above, paste 90 may also contain NIR absorbing dyes, such as diimide ion complexes, dithioene complexes, and / or phthalocyanines as shown herein. Note that NIR absorbing dyes may be added to silver pastes and / or silver epoxide pastes.

[0049] Some embodiments include a paste for a pattern transfer process, which includes filling a paste into trenches arranged in a specific pattern in a polymer pattern transfer sheet and continuously releasing the paste from the trenches onto a receiving substrate upon irradiation by a laser beam. For example, in the case where the irradiation is in NIR, the paste contains a release material configured to enhance the release of the paste from the trenches, wherein the release material contains at least one NIR absorbing dye, said NIR absorbing dye comprising at least one of: diimide ion complexes, dithioene complexes, phthalocyanines, their derivatives, their salts, and / or combinations thereof. Non-limiting examples include dyes from TCI (Tokyo Chemical Industry, Ltd.) and Epolin's Epolight. TM. 1117 (tetra(decyl)ammonium structure) and / or Luminochem's Lunir5 TM .

[0050] Figure 3A and Figure 3BThis is a high-level schematic side view of the release layer coating process 210 according to some embodiments of the present invention. In several embodiments, the coating 120 used as the release layer can be deposited or applied by any known technique such as gravure coating, microgravure coating, transfer roller coating, slot (die) extrusion coating, reverse comma coating, Mayer bar coating, doctor blade coating, or other techniques, applied by a corresponding coating machine.

[0051] For example, Figure 3A A blade coating method is schematically illustrated, which uses at least one blade 140, 140A to fill the trenches 110 with a coating solution 121 (schematically shown, indicated by numeral 122 when within the trenches 110) while keeping the surfaces between the trenches clean. After the coating solution 122 is dried, a coating 120 is formed within the trenches 110 with a thickness determined primarily by the solids content of the coating solution 121. A cavity-sealing blade 140A (protecting or sealing the coating solution 121) can be configured to improve control of the coating solution 121 and ensure the cleanliness of the surfaces between the trenches.

[0052] Alternatively or possibly supplementary, Figure 3B The diagram schematically illustrates coating deposition followed by surface cleaning between the trenches 110. A coating solution 123 can be applied to at least a portion of the surface of the pattern transfer sheet 100 using, for example, a plating technique, spraying, slot extrusion, etc., and dried to form a coating 120 and residue 124 on the surface between the trenches 110. The residue 124 can be removed by various methods, such as a doctor blade 145 (e.g., made of metal, plastic, rubber, etc.) positioned at a specific angle, an adhesive roller 146, etc.—leaving the coating 120 within the trenches 110. The removed residue can be recovered.

[0053] Any disclosed coating method 210 can be performed in a fixed mode (with a fixed pattern transfer sheet 100 and individual coating elements that move relative to it) and / or in a continuous mode (with fixed coating elements and a pattern transfer sheet 100 that moves relative to it, for example, using a roller in a roller-to-roll method).

[0054] The coating process 210 can be performed before the pattern transfer sheet 100 is fed into the PTP system 101, or during their movement in the PTP system 101, for example, just before the groove is filled with slurry.

[0055] In several embodiments, surface treatment techniques such as plasma (e.g., corona discharge), application of silane additives, etc., can be used to treat at least the surface of trench 110 to enhance or control the adhesion of coating 120 thereto. Surface treatment can be configured to balance the desired coating adhesion within trench 110, the removal of residues from the surfaces between trenches (if necessary), the release of slurry through coating decomposition, and possible sheet recycling considerations.

[0056] In several embodiments, the PTP system 101 can be configured, for example, to inspect and control the coating and cleaning processes at a print quality station that controls the print quality of the grid lines (grid lines) to keep the processes within a predefined process window. In some embodiments, monitoring of residual released material can be performed as part of a slurry recovery process associated with the PTP system 101.

[0057] The disclosed sheet 100 can be used to print fine lines of thick metal paste on silicon wafers, such as those used for photovoltaic (PV) cells, and to produce electronic circuits by creating conductive lines or pads or other features (e.g., on laminates for PCBs) for printing passive electronic components such as resistors or capacitors, or for other printed electronic devices. Other applications may include creating conductive features in manufacturing processes for: mobile phone antennas, decorative and functional automotive glass, semiconductor integrated circuits (ICs), semiconductor IC package connections, printed circuit boards (PCBs), PCB assembly, optical, biological, chemical and environmental sensors and detectors, radio frequency identification (RFID) antennas, organic light-emitting diode (OLED) displays (passive or active matrix), OLED illuminators, printed cells, and other applications. For example, in non-limiting solar applications, the metal paste may comprise metal powder, optional glass frit and modifiers, volatile solvents and non-volatile polymers and / or resins. Non-limiting examples of pastes include those from Heraeus TM SOL9651B TM .

[0058] The slurry can be filled into the trench 110 by any type of slurry filling head 60 operating within any type of PTP system 101. Figure 4B (See, for example, non-limiting embodiments in Chinese Patent Application Nos. 202110673006.5 and 202121350578.1 and Israeli Patent Application No. 294060, which are incorporated herein by reference in their entirety.) The filling process can be controlled to ensure that the grooves and markings are filled with slurry continuously and uniformly.

[0059] In some embodiments, the pattern transfer sheet 100 may be transparent to the laser beam 140 and includes at least a top polymer layer 114, said top polymer layer 114 including grooves 110 thereon formed by embossing, compression molding, pneumatic molding, or laser molding. Figure 1 (as shown in the figure). In the non-limiting example shown, the groove 110 is shown as trapezoidal in cross-section.

[0060] Periodic grooves 110 may include trenches, recesses, and / or indentations imprinted in a similar manner (e.g., compression molding, pneumatic molding, or laser molding) into the top polymer layer 114, and may have similar or different profiles. For example, grooves 110 may have various profiles (cross-sectional shapes), such as trapezoidal, circular, square, rectangular, and / or triangular profiles. In several embodiments, the pattern of grooves 110 on the transfer sheet 100 may include an array of continuous grooves 110 and / or separated indentations. Note that the term "groove" should not be construed as limiting the shape of groove 110 to linear elements, but is understood broadly to include grooves 110 of any shape.

[0061] The pattern transfer sheet 100 may further include a bottom polymer layer 112, the melting temperature of which is higher than the imprinting temperature of the top polymer layer 114. In a non-limiting example, the top polymer layer 114, when made of a semi-crystalline polymer, may have a melting temperature (T) below 170°C, below 150°C, below 130°C, below 110°C (or any intermediate range). m ), or, if it is made of an amorphous polymer, it may have a glass transition temperature (T) below 160°C, below 140°C, below 120°C, below 100°C (or any intermediate range). g The melting temperature of the bottom polymer layer 112 can be higher than the melting point of the top polymer layer 114, for example, above 100°C (e.g., in a top polymer layer 114 made of polycaprolactone and having a T0 of about 70°C). m / T g (in the case of) above 120°C, above 150°C, above 160°C (e.g., biaxially oriented polypropylene) and up to 400°C (e.g., certain polyimides), or intermediate values.

[0062] In several embodiments, polymer layers 112, 114 may be made of at least one of the following: polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, fully aromatic polyester, other polyester copolymers, polymethyl methacrylate, other acrylate copolymers, polycarbonate, polyamide, polysulfone, polyethersulfone, polyetherketone, polyamide-imide, polyether-imide, aromatic polyimide, alicyclic polyimide, fluorinated polyimide, cellulose acetate, cellulose nitrate, aromatic polyamide, polyvinyl chloride, polyphenol, polyarylate, polyphenylene sulfide, polyphenylene ether, polystyrene, or combinations thereof—provided that the melting temperature or glass transition temperature (T0) of the top polymer layer 114 is within acceptable limits. m / T g The melting temperature or glass transition temperature (T) of the bottom polymer layer 112 is lower than that of the bottom polymer layer 112. m / T g This can be done as long as the bottom polymer layer 112 is not affected by the processing conditions of the top polymer layer 114.

[0063] In some embodiments, the bottom polymer layer 112 and the top polymer layer 114 may each be 10 μm to 100 μm thick, for example, 15 μm to 80 μm, 20 μm to 60 μm, 25 μm to 40 μm, or any intermediate range, wherein the bottom polymer layer 112 is at least as thick as the top polymer layer 114. The bottom polymer layer 112 and the top polymer layer 114 may be attached by an adhesive layer 113 that is transparent to the laser beam 80 and thinner than 10 μm (e.g., thinner than 8 μm, thinner than 6 μm, thinner than 4 μm, thinner than 2 μm, or has any intermediate thickness). For example, in some embodiments, the top polymer layer 114 may be several μm thicker than the depth of the trench 110, for example, 5 μm, 3 μm to 7 μm, 1 μm to 9 μm, or up to 10 μm thick. For example, the trench 110 may be 20 μm deep, the top polymer layer 114 may be 20 μm to 30 μm thick (e.g., 25 μm thick), and the thickness of the bottom polymer layer 112 may be in the range of 30 μm to 40 μm (note that a thicker bottom polymer layer 112 provides better mechanical properties).

[0064] The temperature and thickness of the top polymer layer 114 and the bottom polymer layer 112 can be designed to give the top polymer layer 114 good formability, ductility, and certain mechanical strength, while the bottom polymer layer 112 has good mechanical strength. Both the top polymer layer 114 and the bottom polymer layer 112 can be designed to have good adhesive properties.

[0065] From Figures 1 to 4BThe elements can be combined in any operable combination, and the illustration of certain elements in some figures but not in others is for illustrative purposes only and is not restrictive. Note that the disclosed values ​​can be modified by at least ±10% of the corresponding values.

[0066] Figure 4A This is a high-level flowchart illustrating a method 200 for monitoring pattern transfer printing according to some embodiments of the present invention. The method steps can be performed using a pattern transfer sheet 100 and / or with respect to the aforementioned PTP system 101, which may optionally be configured to implement method 200.

[0067] Method 200 includes internally coating a plurality of trenches of a pattern transfer sheet with a release layer material (step 210), said release layer material being configured to decompose upon irradiation to release paste filling the coated trenches. The trenches are configured to be filled with printing paste (see step 240) and to release the printing paste from the trenches onto a receiving substrate upon irradiation by a laser beam (see step 250). The coating is configured to decompose upon irradiation to enhance paste release.

[0068] In some embodiments, method 200 may include coating 210 by applying a coating solution (e.g., with a solid content of 10% to 20% by weight, or 12%, 14%, 16%, 18% by weight, or an intermediate value, and using, for example, a doctor blade, roller, die, etc.), and drying the release layer to form a solid layer for trenching (step 220). For example, the thickness of the solid layer may be in the range of 1 μm to 10 μm (e.g., 3 μm, 5 μm, 7 μm, 9 μm, or an intermediate value). Method 200 may also optionally include cleaning coating residues on the surface between the trenches of the pattern transfer sheet, for example, using a doctor blade and / or adhesive roller (step 230).

[0069] Method 200 may further include cleaning the receiving substrate by removing the decomposition products of the coating from the receiving substrate (step 260), for example via at least one of the following: high-temperature decomposition, selective laser vaporization, vacuum-assisted vaporization, blowing, and / or solvent washing. In some embodiments, cleaning 260 may optionally be performed by irradiation that is the same as or similar to that used for releasing the printing paste, or by other methods such as baking and / or washing.

[0070] Figure 4BThis is a high-level schematic diagram of options for using dye in method 200 and PTP system 101 (specifically with respect to slurry filling head 60) according to some embodiments of the invention. In several embodiments, achieving the disclosed use of radiation-absorbing dye to improve slurry release from the trench (step 202) can be done by mixing the dye into the slurry (step 205 and further below) and / or coating the trench in the pattern transfer sheet with the dye (step 210). Mixing the dye into the slurry can advantageously be done before filling the trench, for example by preparing a slurry with the mixed dye before using the filling head 60 (step 206), for example as a preparation step or even in a separate facility (indicated by two different arrows) and / or by mixing the dye into the slurry in the filling head, and filling the trench with the slurry (step 208). For example, the dye solution can be introduced into the mixer unit in the filling head 60 (see, for example, non-limiting embodiments in Chinese Patent Applications Nos. 202110673006.5 and 202121350578.1 and Israeli Patent Application No. 294060, which are incorporated herein by reference in their entirety), for example, using a syringe dispenser located just before the paste mixer, so that the dye solution is uniformly mixed into the printing paste. In such an embodiment (208), the amount and / or type of dye solution can be adjusted relative to the following on-the-spot printing requirements: for example, the width of the processing window wafer, the processing window markings on the relevant wafer portion (see, for example, Chinese Patent Application Nos. 2021108029807, 2021216151878, 202111034191X and 2021221306455, and U.S. Patent Application No. 17 / 864,419, which are incorporated herein by reference in their entirety), the desired and / or resulting print quality monitored by the PTP system 101 and / or according to any other print quality control method or apparatus.

[0071] Figures 5A to 5C The effects of using coating 120 on the quality of printing and the amount of residue remaining on the receiving substrate are shown in some embodiments of the invention. Figures 5A to 5C The experimentally deposited grid line 90B is shown, with magnified images revealing the characteristics of the grid line itself and the surrounding residue (slurry and coating residue). In all three cases, the width / height ratio was similar, specifically 23 μm / 11 μm, 21 μm / 14 μm, and 24 μm / 13 μm, respectively. Figure 5A In the middle, no coating 120 is used and the grid lines represent the existing technology lines 60. Figure 5B and Figure 5CIntermediate states 130 are shown after slurry release 250 and before substrate cleaning 260, using a thin coating 120 (estimated thickness in the range of 1 μm to 3 μm) and a thicker coating 120 (estimated thickness in the range of 3 μm to 5 μm). Figures 5A to 5C As can be seen, compared to the uncoated trench 110 ( Figure 5A ), coating 120 ( Figure 5B , Figure 5C Both reduced residue levels, with the thicker coating (120) showing greater effectiveness in reducing residue around grid line 90B. Figure 5C ) thinner coating 120 ( Figure 5B More effective.

[0072] Figure 6A and Figure 6B The effect of substrate cleaning 260 by heat treatment (at about 250°C) according to some embodiments of the present invention is shown. Figure 6A and Figure 6B The images show the deposited mesh lines 90B in intermediate state 130 before cleaning 260 and the wafer 75 after cleaning, free of coating decomposition products and residues, with magnified images showing surface details. (See also...) Figure 6B It can be seen that the coating residue 120B was removed from the wafer surface through the cleaning process.

[0073] Figure 7A and Figure 7B The ability to produce extremely fine mesh lines 90B using coating 120 according to some embodiments of the invention is demonstrated. Specifically, Figure 7A The image shows a gate line (grid line) 90B on wafer 75, 18 μm wide and 13 μm high, providing an aspect ratio of 0.72—as shown in the magnified image and measurement plot; and Figure 7B The image shows an even finer 13μm wide and 12μm high gate line (grid line) 90B on wafer 75, providing an aspect ratio of 0.92.

[0074] While in some embodiments the release material may be provided as a separate layer 120 within trench 110, some embodiments may include mixing a portion of the release material with paste 90 to improve the release of paste 90. Mixing the release material into paste 90 may produce a minor improvement in print quality without adding a coating process (deposition of coating 120). The disclosed release material may be added to achieve a few percent by weight of paste 90, for example, 1% to 5% by weight. In some embodiments, both coating 120 and mixing the release material into paste 90 may be applied.

[0075] Table 1 and Figure 8The following experimental results are provided: different mixtures of dye (20 wt%) in acetone solution with silver (Ag) paste—the dye was added to the silver paste at 1 wt%, 2 wt%, and 3 wt% (mixture percentage, expressed in the term dye loading), and the paste used in different combinations of laser irradiation intensity and process window width (e.g., the effective width of the laser beam) for depositing the silver paste grid lines. Table 1 also provides the resulting dimensions of the deposited grid lines and a qualitative assessment of the level of residue and grid line waviness to indicate print quality. Figure 8 Illustrations of corresponding grid lines 90B printed under different parameter values ​​according to some embodiments of the present invention are provided. Commercially available Clearweld 920 dye and Heraeus SOL9651B paste were used in the printing process.

[0076] Table 1: Experimental printing of dyes in different mixtures in the paste and under different lighting intensities.

[0077]

[0078]

[0079] In a non-limiting experimental example, optimal printing results were achieved at a 20 wt% concentration solution with a 3 wt% dye load. At higher dye loads (7 wt%), the laser irradiation power required to reach a sufficient processing window is high (300 W or higher absorbed by the dye), resulting in high levels of residue and excessively low paste viscosity, leading to scooping and collapse during paste filling, which impairs the proper shape of the grid lines. However, it should be noted that variations in dye concentration in the dye-acetone solution (e.g., below 20 wt%), or variations in the dye solution or paste composition (e.g., different dyes, different solvents, different pastes), can lead to different optimal dye loads, and therefore any of these parameters can be adjusted in practice.

[0080] In several embodiments, the slurry solvent can be adjusted to maintain sufficient viscosity after loading the dye (e.g., as 20% by weight of dye in an acetone solution, in other concentrations and / or solvents). For example, two or more different solvents can be combined to control the solubility parameters of the mixed solution—to achieve a specified solution viscosity with a given solubility parameter (a numerical value indicating the relative solubility behavior of a particular solvent). For example, using the Hansen solubility parameter (in units of the square root of pressure, relating to different types of interactions between molecules of two or more solvents, specifically, δD related to dispersive forces, δP related to dipole forces, and δH related to hydrogen bonding)—a mixture of solvents can be selected to dissolve the dye and provide an average solubility parameter corresponding to the desired solution viscosity and rheological behavior to produce specified slurry deposition parameters (e.g., a desired high aspect ratio and low levels of residue and ripple). For example, two or more solar cell metallization solvents with low vapor pressure and slow evaporation / drying (e.g., ether-glycol solvent series, such as butylcarbitol (2-(2-ethoxyethoxy)ethanol), butylcarbitol acetate, texanol (C 12 H 24 O3) and α-terpineol (C 10 H 18 O) etc. can be mixed arbitrarily to provide the desired solubility parameters that cause the desired paste properties when mixed with dyes in acetone solution.

[0081] As a non-limiting example, to utilize a mixture of solvents used for metallization of solar cells and having a solubility parameter similar to acetone as a solvent for dyes, Table 2 suggests a non-limiting mixture of butyl carbitol and acetonitrile, which has a solubility parameter close to that of acetone and can be used to dissolve dyes while maintaining parameters required for printing pastes (mixed with dyes). The mixed solution containing dye can be added to existing pastes or used as part of paste manufacturing.

[0082] Table 2: Non-limiting examples of solvent mixtures for slurries and dyes.

[0083]

[0084] In several embodiments, the mixture of solar cell metallization solvents used in Ag paste formulations can be configured to have solubility parameters in the following ranges: δD can be from 14√MPa to 17√MPa, δP can be from 4√MPa to 10√MPa or 11√MPa, and δH can be from 7√MPa to 11√MPa. The final solubility parameters of the dye solution can be configured to these ranges by solvent mixing. As a non-limiting example, Table 3 provides typical Hansen parameters for common silver paste solvents that can be mixed to obtain solvents within the ranges disclosed above.

[0085] Table 3: Typical Hansen parameters for common silver paste solvents.

[0086]

[0087] Non-limiting examples of NIR absorbing dyes include diammonium ion complexes, dithioene complexes, and / or phthalocyanines, as illustrated herein. Non-limiting examples for printing pastes include silver pastes (e.g., Heraeus). TM SOL9651B TM ) and / or silver epoxide slurry. The dye can be mixed directly with the slurry or mixed into the slurry as a solution, wherein non-limiting examples of solutions include acetone-based ClearWeld TM LD920 series and acrylic resins, such as Epolin's Spectra 390 TM .

[0088] In several embodiments, the disclosed slurry composition may, by weight, comprise 50% to 90% silver particles, 1% to 10% solvents as disclosed herein, 1% to 5% glass frit, 1% to 5% polymer binder, 1% to 5% additives (e.g., viscosity modifiers or surfactants), and 1% to 7% of the disclosed dye, wherein the NIR absorbing dye comprises at least one of the following: diimide ion complexes, dithioene complexes, phthalocyanines, their derivatives or salts and / or combinations thereof.

[0089] Figure 9Illustrations of grid lines printed using a dye-mixed paste according to some embodiments of the invention are provided. These images are magnified to ×5 and ×50. In some embodiments, the disclosed paste composition may contain, by weight, 50% to 90% silver particles, 1% to 5% glass frit, 1% to 5% polymer binder, 1% to 5% additives, and 0.1% to 1% NIR absorbing dye, wherein the NIR absorbing dye includes at least one of the following: diimide ion complexes, dithioene complexes, phthalocyanines, their derivatives, or salts and / or combinations thereof. Direct dye mixing expands the range of available dyes to include, for example, cyanine blue derivatives, or their salts and / or combinations thereof with other dyes.

[0090]

[0091] In some implementations, 0.1% to 1% of the NIR absorbing dye can be directly mixed into the printing paste, avoiding the use of solvents. For example, in the illustration, powdered NIR dye (Luminochem's LUNIR5) is mixed with PV silver paste (Heraeus 9681B) using a planetary mixer with mechanical stirring. In this example, 0.6% by weight of the dye is mixed into the paste and printed under laser irradiation intensity of 200W, resulting in clean and continuous lines. Indeed, direct dye mixing can require lower irradiation intensity than printing paste alone and leaves less residue during release.

[0092] In the above description, embodiments are examples or implementations of the invention. The various appearances of "an embodiment," "an embodiment," "certain embodiments," or "some embodiments" do not necessarily all refer to the same embodiment. While multiple features of the invention may be described in the context of a single embodiment, these features may also be provided individually or in any suitable combination. Conversely, although the invention may be described herein in the context of individual embodiments for clarity, the invention may also be implemented in a single embodiment. Certain embodiments of the invention may include features from different embodiments disclosed above, and certain embodiments may incorporate elements from other embodiments disclosed above. The disclosure of elements of the invention in the context of a particular embodiment should not be construed as limiting the use of the elements only in that particular embodiment. Furthermore, it should be understood that the invention can be carried out or practiced in various ways, and the invention may be implemented in certain embodiments other than those outlined in the above description.

[0093] This invention is not limited to the figures or corresponding descriptions. For example, the process does not need to move through each shown box or state, or in the exact same order as shown and described. Unless otherwise defined, the meanings of the technical and scientific terms used herein should be commonly understood by one of ordinary skill in the art to which this invention pertains. Although the invention has been described with respect to a limited number of embodiments, these should not be construed as limiting the scope of the invention, but rather as examples of some preferred embodiments. Other possible variations, modifications, and applications are also within the scope of this invention. Therefore, the scope of the invention should not be limited by what has been described so far, but by the appended claims and their legal equivalents.

Claims

1. A pattern transfer sheet comprising: a plurality of grooves arranged in a specific pattern, wherein the grooves are coated with a coating inside and filled with a printing paste on top of the coating, wherein the coating is configured to decompose upon irradiation by a laser beam, and the decomposition of the coating releases the printing paste from the grooves onto a receiving substrate; and wherein the coating is coated only inside the grooves, and the thickness of the coating is 1 pm to 10 pm.

2. The pattern transfer sheet of claim 1, wherein the coating comprises: at least one organic-based dye that absorbs the irradiation by the laser beam, wherein a decomposition product of the coating on the receiving substrate degrades or decomposes at a temperature lower than a sintering temperature or a curing temperature of the printing paste; at least one solvent; and optionally at least one of the following: a binder, a surfacer, and a viscosity modifier.

3. The pattern transfer sheet of claim 2, wherein the irradiation is near-infrared and the at least one dye comprises at least one near-infrared absorbing dye.

4. The pattern transfer sheet of claim 3, wherein the at least one near-infrared absorbing dye comprises at least one of the following: a diimmonium ion complex, a dithioene complex, a phthalocyanine, a derivative thereof, and / or a salt and / or a combination.

5. The pattern transfer sheet of any one of claims 1 to 4, wherein a decomposition product of the coating degrades or decomposes below a sintering temperature of the printing paste of 850 °C.

6. The pattern transfer sheet of any one of claims 1 to 4, wherein a decomposition product of the coating degrades or decomposes below a curing temperature of the printing paste of 300 °C.

7. The pattern transfer sheet of any one of claims 1 to 4, wherein a solid content of the coating is 10 wt% to 20 wt%.

8. The pattern transfer sheet according to any one of claims 1 to 4, wherein the pattern transfer sheet is transparent to laser irradiation, and the grooves are formed in the pattern transfer sheet by press forming, pneumatic forming, laser forming, or stamping.

9. The pattern transfer sheet according to claim 8, wherein a cross-section of the grooves is any one of the following: trapezoidal, rectangular, circular, or triangular.

10. The pattern transfer sheet according to claim 8, wherein the pattern transfer sheet comprises at least one polymeric layer made of at least one of the following: polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, wholly aromatic polyester, aromatic-aliphatic copolyester, acrylate copolymer, polycarbonate, polyamide, polysulfone, polyethersulfone, polyetherketone, polyamide-imide, polyether-imide, aromatic polyimide, alicyclic polyimide, fluorinated polyimide, cellulose acetate, cellulose nitrate, aromatic polyamide, polyvinyl chloride, polyphenol, polyarylate, polyphenylene sulfide, polyphenylene ether, or polystyrene.

11. The pattern transfer sheet according to claim 8, wherein the pattern transfer sheet comprises at least: a top polymeric layer comprising the grooves, and a bottom polymeric layer having a melting temperature higher than a stamping temperature of the top polymeric layer.

12. The pattern transfer sheet according to claim 11, wherein the top polymeric layer has a melting temperature lower than 170 °C if made of a semi-crystalline polymer, or a glass transition temperature lower than 160 °C if made of an amorphous polymer.

13. The pattern transfer sheet according to claim 12, wherein The top polymer layer has a melting temperature below 110°C if made of semi- crystalline polymer, or a glass transition temperature below 100°C if made of amorphous polymer.

14. The pattern transfer sheet of claim 12, wherein The top polymer layer and the bottom polymer layer are each 10 to 100 pm thick, the top polymer layer and the bottom polymer layer are attached by an adhesive layer thinner than 10 pm transparent to laser irradiation, and wherein the bottom polymer layer is at least as thick as the top polymer layer.

15. The pattern transfer sheet of claim 12, wherein The top polymer layer and the bottom polymer layer are each 25 to 40 pm thick, the top polymer layer and the bottom polymer layer are attached by an adhesive layer thinner than 2 pm transparent to laser irradiation, and wherein the bottom polymer layer is at least as thick as the top polymer layer.

16. A pattern transfer method, comprising: applying a coating inside a plurality of trenches arranged in a specific pattern on a pattern transfer sheet to form a coating within each trench of the plurality of trenches, filling a printing paste on top of the coating inside the plurality of trenches, releasing the printing paste from the trenches onto a receiving substrate by laser beam irradiation to obtain a transferred paste line having the specific pattern on the receiving substrate, wherein the coating is decomposed upon the irradiation by the laser beam to enhance the release of the printing paste, wherein decomposition products of the coating on the receiving substrate degrade or decompose at a temperature lower than a sintering or curing temperature of the printing paste; and wherein the coating is applied only inside the trenches, and a thickness of the coating is 1 to 10 pm.

17. The pattern transfer method of claim 16, wherein the applying is performed by coating and drying a coating solution having a solid content of 10 to 20%.

18. The pattern transfer method of claim 17, wherein the applying is performed by at least one of the following: gravure coating, transfer roll coating, slot-die coating, reverse comma coating, Mayer rod coating, blade coating.

19. The pattern transfer method of claim 17, wherein the applying is performed by microgravure coating.

20. The pattern transfer method of any one of claims 16 to 19, further comprising removing the decomposition products of the coating from a surface of the receiving substrate.

21. The pattern transfer method of claim 20, wherein the removing is performed by at least one of the following: pyrolysis, selective laser vaporization, vacuum assisted vaporization, air blowing, and / or solvent washing.

22. The pattern transfer method of claim 20, wherein the removing is performed by the same irradiation as the irradiation used to release the printing paste.

23. A pattern transfer method, comprising: mixing a laser absorbing dye into a printing paste, wherein the printing paste contains 1 to 3% of near-infrared absorbing dye by weight percentage, filling the printing paste into a plurality of trenches arranged in a specific pattern on a pattern transfer sheet, releasing the printing paste from the trenches onto a receiving substrate by laser beam irradiation to obtain a transferred paste line having the specific pattern on the receiving substrate, wherein the coating is decomposed upon the irradiation by the laser beam to enhance the release of the printing paste, wherein decomposition products of the coating on the receiving substrate degrade or decompose at a temperature lower than a sintering or curing temperature of the printing paste; and wherein the coating is applied only inside the trenches, and a thickness of the coating is 1 to 10 pm. by releasing the printing paste from the trenches onto a receiving substrate by irradiation with a laser beam to form a corresponding specific pattern of paste lines on the receiving substrate, wherein the laser absorbing dye mixed into the printing paste decomposes upon irradiation with the laser beam to release the printing paste from the trenches.

24. The pattern transfer method according to claim 23, wherein the mixing is carried out in a preparation step before filling the trenches with the printing paste.

25. The pattern transfer method according to claim 23, wherein the mixing is carried out shortly before filling the trenches with the printing paste in conjunction with the respective paste filling head.

26. The pattern transfer method according to any one of claims 23 to 25, further comprising cleaning the receiving substrate by removing decomposition products of the dye from the receiving substrate.

Images