Intermittently photobleached mask and method of making and using same for component transfer - Patents.com

Abstract

Intermittently photobleached masks having photobleachable and photobleached regions and their fabrication and use for selectively releasing components from a substrate are described. Intermittently photobleached masks can facilitate component transfer by simultaneously releasing multiple selected components from a donor plate that includes a release layer.

Description

[Technical field]

[0001] INCORPORATION BY REFERENCE OF PRIORITY APPLICATION Any and all applications for which a foreign or domestic priority claim is identified in an Application Data Sheet or application filed with this application are incorporated herein by reference under 37 CFR 1.57 and Rules 4.18 and 20.6. U.S. Provisional Patent Application No. 63 / 169,701, filed April 1, 2021, is incorporated herein by reference in its entirety.

[0002] The invention is directed to the manufacture of electronic systems comprised of several different components including, for example, displays using individual light emitting diodes, or microelectronic multi-chip circuits. [Background technology]

[0003] The transfer of microelectronic objects from one surface to another extends the methods of assembly and packaging of functional products, whether such products are entirely electronic (as in computer motherboards), optoelectronic (as in displays), sensors, or actuators. The physics of the patterning system limits the size of the systems that can be fabricated in one integrated parallel process, and process compatibility limits the types of materials. Therefore, useful systems require integration at the package level.

[0004] Integrated circuits have allowed various components (e.g., passive components) to be manufactured with the same technology as transistors, allowing entire functional circuits to be created by parallel processing; i.e., simultaneous processing of areas rather than devices. U.S. Patent No. 6,946,178 and U.S. Patent No. 7,141,348 to Sheets et al., which are incorporated herein by reference, disclose a method for transferring or printing thin film devices to a target substrate from a donor substrate (also referred to herein as a donor plate) on which a polymeric light-activated thermal transfer material has been applied in thin film.

[0005] Many techniques are currently used to process microelectronics, such as sequential pick and place, laser ablation, stamping and bonding, but improved techniques for transferring component selections would be beneficial. Summary of the Invention

[0006] For the purpose of summarizing the present disclosure and the advantages achieved over the prior art, certain objects and advantages of the present disclosure are described herein. Not all such objects or advantages may be achieved in any particular embodiment. Thus, for example, one skilled in the art will understand that the present invention may be embodied or implemented to achieve or optimize one or a group of advantages taught herein without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0007] In one aspect, an intermittently photobleached mask is described that includes an intermittently photobleached layer comprising a photobleachable material and a substrate disposed over the intermittently photobleached layer, the intermittently photobleached layer including photobleached regions that are at least partially transparent to light at an ablation wavelength, and non-photobleached regions that are substantially opaque to light at an ablation wavelength.

[0008] In some embodiments, the photobleachable material comprises a base polymer and a polycyclic aromatic hydrocarbon compound. In some embodiments, the polycyclic aromatic hydrocarbon compound is selected from the group consisting of acene, tetracene, pentacene, rubrene, anthradichromene, dianthrone, and combinations thereof. In some embodiments, the polycyclic aromatic hydrocarbon compound is selected from the group consisting of 9,10-dimethylanthracene (DMA), 9,10-diphenylanthracene (DPA), 1,4,9,10-tetraphenylanthracene, 5,12-diphenyltetracene, and combinations thereof. In some embodiments, the polycyclic aromatic hydrocarbon compound is substituted with a substituent selected from the group consisting of an alkyl, an aryl, a siloxane, and combinations thereof. In some embodiments, the siloxane is substituted with a substituent selected from the group consisting of a polyacetylene, a fluoropolymer, a poly(norbornene), and combinations thereof. In some embodiments, the base polymer comprises a polymer selected from the group consisting of an acrylate polymer, a siloxane polymer, and combinations thereof. In some embodiments, the acrylate polymer is selected from the group consisting of poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(butyl methacrylate) (PBMA), and combinations thereof.

[0009] In some embodiments, the light at the ablation wavelength is about 250-370 nm. In some embodiments, the photobleached regions are at least about 60% transparent to light at the ablation wavelength. In some embodiments, the non-photobleached regions are up to about 10% transparent to light at the ablation wavelength. In some embodiments, the substrate is transparent to light at the ablation wavelength.

[0010] In another aspect, a method of using an intermittently photobleached mask is described, the method comprising: disposing the intermittently photobleached mask on a transfer assembly including a donor plate, a release layer disposed on the donor plate, and a plurality of components disposed on the release layer, the plurality of components including at least one selected component disposed on and at least partially overlapping with at least one selected release layer region, and the photobleached region is aligned with the at least one selected release layer region, the method comprising: directing light at a release wavelength through the photobleached region onto at least one of the release layer regions, thereby degrading at least one of the release layer regions and forming at least one release component.

[0011] In some embodiments, the method of use further comprises transferring at least one of the exfoliated parts to a receiving substrate. In some embodiments, the at least one exfoliated part comprises multiple exfoliated parts, and multiple exfoliated parts are transferred to the receiving substrate simultaneously. In some embodiments, the method of use further comprises directing the exfoliation wavelength light through a second mask to the photobleached region. In some embodiments, the second mask prevents exposure of additional photobleached regions of the intermittently photobleached mask to the exfoliation wavelength light. In some embodiments, the method further comprises moving the second mask relative to the intermittently photobleached mask and the transfer assembly after directing the exfoliation wavelength light through the second mask, and the relative positions of the intermittently photobleached mask and the transfer assembly are substantially the same. In some embodiments, the method further comprises applying heat to at least one of the exfoliation layer regions. In some embodiments, the exfoliation wavelength light is directed through the substrate to at least one of the exfoliation layer regions.

[0012] In another aspect, a method of making an intermittently photobleached mask is described, the method comprising the steps of providing a photobleachable layer disposed on a substrate, the photobleachable layer being substantially opaque to light at a stripping wavelength, exposing the photobleachable layer to an atmosphere comprising oxygen gas; and irradiating selected areas of the photobleachable layer to form an intermittently photobleached layer including photobleached areas that are at least partially transparent to light at the ablation wavelength.

[0013] In some embodiments, the method further comprises depositing a photobleachable layer on the substrate. In some embodiments, the atmosphere is air or an oxygen-rich atmosphere. In some embodiments, the irradiation is performed at a photobleaching wavelength of 250-550 nm.

[0014] These and other features, aspects, and advantages of the present disclosure will be described with reference to illustrations of certain embodiments that are intended to be illustrative of the certain embodiments and not limiting of the invention. [Brief description of the drawings]

[0015] [Figure 1] 1A-1C illustrate a method for increasing element separation and replacing selected elements according to some embodiments. [Diagram 2] FIG. 2 is a graph showing the unirradiated and photobleached absorption spectra of a film of 9,10-diphenylanthracene (“DPA”) in poly(ethyl methacrylate) (“PEMA”). [Diagram 3] Figure 3A is a graph showing the photobleaching kinetics of 9,10-dimethylanthracene ("DMA") in poly(ethyl methacrylate) ("PEMA") films and 9,10-diphenylanthracene ("DPA") in poly(butyl methacrylate) ("PBMA") films. Figure 3B is a graph showing the stability of oxidized DPA upon irradiation. [Figure 4]FIG. 4 is an illustration of a photobleached masked arrangement for removing elements from a donor plate, according to some embodiments. [Diagram 5] FIG. 5 is a diagrammatic representation of an arrangement for adjusting the spacing of columns or rows of elements from a donor plate, according to some embodiments. [Figure 6] FIG. 6 is an illustration of a double masked arrangement for removing elements from a donor plate, according to some embodiments. [Figure 7] FIG. 7 is a diagrammatic representation of a donor plate having features selected to be removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Although certain specific embodiments and examples are described below, those skilled in the art will recognize that the invention extends beyond the specifically disclosed embodiments and / or applications and obvious variations and equivalents thereof, and therefore, it is not intended that the scope of the invention disclosed herein should be limited by any of the specific embodiments described below.

[0017] Masks including photobleachable materials and their fabrication and use for selectively releasing components from a substrate are described. The photobleachable material of the mask can be photobleached intermittently with a pattern to form an intermittently photobleached mask. Certain regions of the photobleachable material of the mask are photobleached and therefore transparent or substantially transparent to certain wavelengths of light, while other regions remain unphotobleached and therefore opaque or substantially opaque to the same wavelengths of light. The intermittently photobleached regions or patterns can correspond to selected features (e.g., defective or non-defective chips) on a substrate (e.g., a donor plate). Such intermittently photobleached masks can be used to release selected features from a release layer, thereby transferring such selected features in parallel to another substrate.

[0018] Assemblies and methods for transferring parts using a peelable adhesive layer are described in U.S. Pat. No. 6,946,178 and U.S. Pat. No. 7,143,333, which are incorporated herein by reference for all purposes. No. 1,348. A triggering process can be used to separate the transfer component from the adhesive layer and place it on the substrate. As described in U.S. Pat. No. 6,946,178, the triggering process involves exposing the release layer to heat and light in a single step to degrade the release layer. Irradiation with light (e.g., actinic light) can be used to selectively activate the polymer under the device that the user wants to transfer, while leaving other devices on the same substrate unactivated. By heating the release layer polymer (also referred to as a digital release material (e.g., digital release adhesive ("DRA"))) to an appropriate temperature (e.g., less than about 150° C.), the release layer can be volatilized and the device can be transferred in close proximity to the target substrate, while leaving the deactivated device on the donor substrate. In this way, such components or objects (e.g., small integrated circuit chips with lateral dimensions less than 100 μm that are difficult or impossible to handle efficiently by other means such as pick-and-place machines) can be placed on the product substrate at high speed. Another exemplary application is light emitting diodes, which are used in active matrix displays and may be only a few microns on each side. This method is sometimes referred to as photo-printed component assembly ("PCA").

[0019] Such methods (e.g., those disclosed in the patents referenced above) allow for selective transfer printing of multiple parts from a donor plate according to an illumination pattern that, in one embodiment, is determined by apertures in a mask. In one example, the mask is configured similarly to an optical mask for contact or projection lithography, where a thin metal film is deposited on a glass or fused silica plate, a resist layer is applied and patterned, and the metal is removed by chemical etching when exposed to light. In some examples, the resist may be exposed by electron beam lithography, by a direct write laser system, or by a spatial light modulator. Typically, one mask pattern is prepared for each part in a given product and reused across many wafers of subsequent parts.

[0020] However, each source wafer may have some selected parts (e.g., defective parts) that, for certain reasons, ideally should not be printed together with the other parts of the wafer. Nevertheless, typical masking methods print the selected parts together with the other parts, resulting in the selected parts (e.g., defective parts) being present in the product. To prevent this, the selected parts (e.g., defective parts) must be removed before the transfer printing process or the mask apertures corresponding to the selected parts' locations must be blocked. Wafer-level test equipment and procedures have become more widely available in recent years, so that wafer-level maps of parts (e.g., defective parts) are likely to be available. One of the objectives of some embodiments of the present disclosure is to provide a cost-effective means of utilizing such information to eliminate defective parts from the product.

[0021] In one embodiment, there are relatively few selected components (e.g., defective components or chips) in the subsequent wafer. In such an embodiment, the donor plate, after it is populated with components (e.g., chips), can pass through a station with a focused laser beam that can be directed sequentially onto any components (e.g., chips) in the array. The selected components (e.g., chips) can be easily removed and collected, for example, for recycling or disposal. The target substrate from which the selected components have been removed will now have voids wherever the defective chips were not transferred. One way to fill the voids is to use the same continuous process: after the usual parallel process, these target substrates with voids are sent through a machine with a directed laser beam to deposit components (e.g., non-defective or good dice) from another donor plate onto the voids.

[0022] In some embodiments, these steps are described in detail in US Pat. No. 6,393,411, which is incorporated by reference in its entirety for all purposes. The process may be performed along the lines of the process described in U.S. Pat. No. 9,406,644 B2, which is incorporated herein by reference. In some embodiments, the components (e.g., chips) undergo two transfers from one release layer coated (e.g., DRA coated) donor plate to another to increase the spacing between them in both axes of the wafer plane, as shown in FIGS. 1A-1C, which may be referred to as a pre-press process or a pre-LIFT (Light-Induced Forward Transfer) process. FIG. 1A shows a device 100a having a plurality of components 102 and a subset of selected components 104a. The donor plate of the device 100a may then be inverted and passed under a laser processing station that directs a laser on the selected components 104a (e.g., defective chips). The selected components 104a may be removed and collected in a container. In some embodiments, the removal of the selected components 104a may be performed before or immediately before the first re-spacing transfer. After the first respacing transfer, FIG. 1B shows a device 100b with multiple components 102 (e.g., chips) present in a release layer coated (e.g., DRA coated) plate with increased spacing in the x direction compared to device 100a, and gaps 104b corresponding to the relative positions of selected components 104a. From FIG. 1A to FIG. 1B, components 102 (e.g., chips) are transferred one entire row at a time from one release layer coated (e.g., DRA coated) donor plate to another. Components 104b (e.g., chips) are then transferred to achieve the desired spacing in the y direction shown in FIG. 1C with device 100c. From FIG. 1B to FIG. 1C, components 102 (e.g., chips) are transferred one entire row at a time from one release layer coated (e.g., DRA coated) donor plate to another.This donor plate of device 100c then passes under another donor plate loaded with additional parts (e.g., the same type of chip, but with good chips) and the laser beam selects and transfers the parts (e.g., chips) into vacant locations at location 104c of device 100c. This step may require more precise positioning than the previous step in which the selected parts 104a (e.g., chips) were discarded, but is still within the normal method flow for a small number of defects.

[0023] The advantage of such a method described with respect to Figures 1A-1C is that it has a high throughput (mainly relying on parallel exposure) while minimizing the process complexity (using sequential laser exposure) and eliminating random defects. Although sequential processing is typically not the preferred exposure procedure because it is slower than parallel processing using a mask, the fact that sequential processing does not require a mask can be advantageous for relatively small numbers of transfers. For example, when the defect rate in a wafer containing 8000 chips (an 8-inch diameter wafer with a chip size of about 2 mm x 2 mm) is 5%, 400 chips need to be eliminated. Using a laser capable of dealing with 1000 spots per second, this operation takes 0.4 seconds, which is comparable to the amount of time required to align the donor plate with the substrate. The movement of the laser beam can still be faster than that in, for example, the take-off process, where very precise alignment is less important, but there is a limit due to the number of pulses per second from the laser. However, such continuous processes (e.g., to remove defective chips) may still be substantially faster and / or less expensive than laser ablation, e.g., as disclosed in U.S. Pat. No. 8,056,222, which requires significantly more energy per pulse.

[0024] However, in some cases (e.g., donor plates for larger defect densities and / or smaller chips with multiple chips on each donor plate), the throughput of such continuous processing may be insufficient. As an example, with approximately 100,000 0.5×0.5 mm chips on an 8 inch wafer, even at 10,000 per second, the same 5% defect density may require a process residence time of 5 seconds, which This is much more than the sub-millisecond time required for a typical implementation of the PCA process with parallel illumination, exceeding 10x the alignment time. In another example, micro LEDs may typically be about 5x5 μm or even smaller, and may number in the millions on a single wafer, with some chips having to be rejected even though they are electrically active because the emission color is outside certain limits due to process variations during fabrication. Thus, even if the conventional electrical defect density may be very low, there may be hundreds of thousands or more of unacceptable chips in a wafer. When the chips are not square, further difficulties arise from using a focused laser beam to replace the chips. Illumination must be uniform to have accurate chip placement, whether by PCA process or simple laser ablation process. Some components, such as ICs, and other components, such as ceramic passive components, may be rectangular with high aspect ratios (e.g., 1 mm x 4 mm, or other such dimensions), and rarely, in fact, any IC that is precisely square. There may be a reasonable process tolerance for rectangles with aspect ratios slightly deviating from 1:1, but it is very limited. Therefore, the beam must generally be shaped with specific optics for each type of chip. An alternative is to block mask apertures where no chips should be printed. A separate thin metal mask may be prepared for each subsequent wafer according to the defect map. This may be efficient, but the method for making such a mask involves several steps that add complexity to the overall method. Therefore, a simplified parallel process may be highly desirable.

[0025] Thus, the present disclosure is directed to a mask substrate coated with a light (e.g., UV light) absorbing material (e.g., including a polymeric material) whose absorbance can be selectively altered, for example, by photobleaching. In some embodiments, the mask substrate is a transparent substrate. In some embodiments, the light absorbing material is a photobleachable material that includes a photobleachable compound. Examples of photobleachable compounds include polymers containing anthracene derivatives (e.g., 9,10-disubstituted anthracenes), as described in U.S. Pat. No. 5,180,655, which is incorporated by reference in its entirety for all purposes. In some embodiments, a thin layer (e.g., less than 1 μm) of such photobleachable compounds (i.e., dyes) in a polymer matrix (e.g., an inert polymer matrix) can effectively completely or substantially block light in a selected wavelength range, for example, deep UV (e.g., 248-270 nm) or near UV (e.g., 350-370 nm) light. However, once the photobleachable compound has been modified to form the photobleached compound, the polymer matrix may effectively completely or substantially allow the transmission of light in a selected wavelength range. For example, Figure 2 (reproduced from J.R.Sheats, Journal of Physical Chemistry, vol. 94, pp. 7194-7200 (1990)) shows that under normal atmosphere (i.e., oxygen-containing atmosphere), the photobleachable compound can reach 47 J / cm at 365 nm. 2 Figure 1 shows the photobleaching of a 0.82 μm thick film of 15.4 wt % 9,10-diphenylanthracene in poly(ethyl methacrylate) irradiated with 1000 mJ / cm. This dose is typically used to obtain complete bleaching, where the majority of the reaction occurs at about 500 mJ / cm. 2 This dose is 200 mJ / cm when an oxygen atmosphere is used. 2The absorbance can be reduced to less than 2.2. Note that the absorbance in the deep UV is stronger than the data shown due to limitations in the spectrometer above an optical density of 2.2. Thus, in the absence of oxygen, 9,10-substituted anthracenes are very photostable and can be used to effectively block UV light. However, in the presence of oxygen, 9,10-substituted anthracenes effectively form endoperoxides that are highly transparent (and photostable) in both the deep and near UV.

[0026] In some embodiments, the selected wavelengths of light selected to be blocked by the photobleachable compound and transmitted through the photobleached compound are wavelengths used to aid in the decomposition of the release layer. In some embodiments, the release wavelengths are 180 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm, 410 nm, 420 nm, 430 nm, 440 nm, 450 nm, 460 nm, 470 nm, 480 nm, 490 nm, 500 nm, 510 nm, 520 nm, 530 nm, 540 nm, 550 nm, 560 nm, 570 nm, 580 nm, 590 nm, 600 nm, 610 nm, 620 nm, 630 nm, 640 nm, 650 nm, 660 nm, 670 nm, 680 nm, 690 nm, 700 nm, 710 nm, 720 nm, 730 nm, 740 nm, 750 nm, 760 nm, 770 nm, 780 nm, 790 nm, 800 nm, 810 nm, 820 nm, 830 nm, 840 nm, 850 nm, 860 nm, 870 nm, 880 nm, 890 nm, 900 nm, 910 nm, 920 nm, 930 nm, 940 nm, 950 nm, 0 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm, or 450 nm, or about said value, or any range of values ​​therebetween. In some embodiments, the photobleached region comprising the photobleached compound is 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 92%, 95%, or 98% transparent to light at the ablation wavelength, or about said value, or at least said value, or at least about said value, or any range of values ​​therebetween. In some embodiments, the non-photobleached regions that contain the photobleachable compound are 0.5%, 1%, 2%, 5%, 8%, 10%, 12%, 14%, 15%, 18%, 20%, or 25% transparent to light at the ablation wavelength, or about that value, or up to about that value, or up to about that value, or any range of values ​​therebetween. In some embodiments, the substrate on which the intermittently photobleached layer is disposed is transparent to light at the ablation wavelength.

[0027] In some embodiments, the mask substrate is deposited with (e.g., coated with) a layer of photobleachable material (e.g., an anthracene compound incorporated in a polymer matrix that may have high oxygen permeability), where the photobleachable layer is opaque to light at the stripping wavelength. The photobleachable layer is irradiated at selected locations or regions to bleach the absorption in those regions and form an intermittently photobleached mask that includes selected locations of the photobleached material. In some embodiments, the selected locations may correspond to the locations of selected components (e.g., defective chips) in the donor plate. In some embodiments, the bleaching reaction of the photobleachable layer is carried out in an oxygen-containing atmosphere (e.g., air, air with excess oxygen, or an oxygen-rich atmosphere). In some embodiments, the bleaching reaction is carried out at a deep UV wavelength (e.g., about 250-270 nm), a near UV wavelength (e.g., about 360-375 nm), or a blue wavelength (e.g., 436 nm). In some embodiments, the photobleaching wavelength is 180 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 375 nm, 380 nm, 390 nm, 400 nm, 410 nm, 420 nm, 430 nm, 435 nm, 440 nm, 450 nm, 475 nm, 500 nm, 525 nm, 550 nm, 575 nm, or 600 nm, or about said value, or any range of values ​​therebetween. In some embodiments, the photobleachable layer further comprises a sensitizer, such as a ketocoumarin. In some embodiments, for example, at these wavelengths, and optionally at low intensities, optical patterns can be conveniently provided by various spatial light modulators. Figure 3A shows the photobleaching kinetics of 9,10-dimethylanthracene ("DMA") in poly(ethyl methacrylate) ("PEMA") film and 9,10-diphenylanthracene ("DPA") in poly(butyl methacrylate) ("PBMA") film.FIG. 3B is (reproduced from J.R. Heats et al., SPIE Proceedings, vol. 631, pp. 171-177 (March 1986)) a 248 nm KrF excimer laser at 25 pps (approximately 10 ns pulses, approximately 1 mJ / cm. 2 1 is a graph showing the stability of oxidized DPA against irradiation in a nitrogen atmosphere according to

[0028] The efficiency of photobleaching, and therefore the throughput of the photomask manufacturing process, depends at least in part on the diffusion of oxygen into the film during exposure. This phenomenon indicates that a larger exposure dose is required in the data in Figures 3A and 3B than if sufficient oxygen were available. Siloxanes can improve the oxygen permeability of the polymer. However, pure siloxanes, especially linear ones, such as poly(dimethylsiloxane), are typically not miscible with carbon-based molecules, such as anthracene. However, the two can be made miscible while still achieving high oxygen permeability. In some embodiments, the photobleachable compound is attached to anthracene, a hydrocarbon polymer, or a combination thereof. The photobleachable compound may be substituted at any position of the molecule. In some embodiments, the photobleachable compound may be substituted with multiple siloxane groups. In some embodiments, the siloxane or siloxane group may be substituted with oligomeric linear chains, trimethylsilyl groups, and combinations thereof. Photobleachable compound compositions and siloxane substitutions are also disclosed in U.S. Pat. No. 5,180,655, which is incorporated by reference in its entirety for all purposes. In some embodiments, the siloxane group may be substituted with polyacetylenes (e.g., poly(trimethylsilylpropyne) and poly(4-methyl-2-pentyne)), fluoropolymers, poly(norbornene), and others described, for example, by PM Budd and NBMcKeown in Polymer Chemistry, vol. 1, pp. 63-68 (2010), which is incorporated by reference in its entirety for all purposes.

[0029] In some embodiments, the photobleachable material comprises a base polymer and a polycyclic aromatic hydrocarbon compound. In some embodiments, the photobleachable compound comprises a polycyclic aromatic hydrocarbon compound. In some embodiments, the polycyclic aromatic hydrocarbon compound comprises an acene, tetracene, pentacene, rubrene, anthradichromene, dianthrone, and combinations thereof. In some embodiments, the polycyclic aromatic hydrocarbon compound is selected from 9,10-dimethylanthracene (DMA), 9,10-diphenylanthracene (DPA), 1,4,9,10-tetraphenylanthracene, 5,12-diphenyltetracene, and combinations thereof. In some embodiments, the polycyclic aromatic hydrocarbon compound is substituted or unsubstituted. In some embodiments, the polycyclic aromatic hydrocarbon compound is an alkyl (e.g., C 1-12 alkyl), aryl (e.g., C 5-10 In some embodiments, the siloxane is substituted with poly(aryl), siloxane, and combinations thereof. In some embodiments, the siloxane comprises poly(diphenylsiloxane) ("PDPS"). In some embodiments, the siloxane is substituted. In some embodiments, the siloxane is substituted with polyacetylene, a fluoropolymer, poly(norbornene), or combinations thereof. In some embodiments, the siloxane may be substituted with poly(trimethylsilylpropyne), poly(4-methyl-2-pentyne), or combinations thereof.

[0030] In some embodiments, the base polymer is selected from an acrylate polymer, a siloxane polymer, and combinations thereof. In some embodiments, the acrylate polymer is selected from poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(butyl methacrylate) (PBMA), and combinations thereof. In some embodiments, the siloxane polymer comprises poly(diphenylsiloxane) ("PDPS"). In some embodiments, the siloxane polymer is substituted. In some embodiments, the siloxane polymer is substituted with a group selected from polyacetylene, a fluoropolymer, poly(norbornene), and combinations thereof. In some embodiments, the siloxane polymer is substituted with a group selected from poly(trimethylsilylpropyne), poly(4-methyl-2-pentyne), and combinations thereof. In some embodiments, the base polymer is substituted or unsubstituted.

[0031] The intermittently photobleached mask, which includes regions of photobleachable and photobleached material, can then be used during a pre-press transfer process to selectively remove selected parts (e.g., defective chips). In some embodiments, the transfer process is performed in an oxygen-depleted atmosphere (e.g., an inert atmosphere, such as nitrogen) to prevent degradation of the mask. In some embodiments, the same mask can be used to transfer chips from another donor plate to empty spots in the target.

[0032] In some embodiments, such an intermittently photobleached mask may be used in the same method flow as described for the oriented laser beam. Prior to the first intermediate transfer step for part (e.g., chip) spacing by part (e.g., chip) arranged as shown in FIG. 1A, defective chips may be removed utilizing an intermittently photobleached mask. FIG. 4 shows an arrangement 400 for removing selected parts (e.g., defective chips) using an intermittently photobleached mask 402 mounted on a lens 406 mounted on a donor plate 408. The intermittently photobleached mask 402 includes photobleached material regions 404 that act as apertures. In some embodiments, the areas of the mask beyond the photobleached material regions 404 include photobleachable material. The transfer assembly including the donor plate 408 further includes a plurality of parts 410 and selected parts 412, and the locations of the photobleached material regions 404 are aligned with or correspond to the locations and areas of the selected parts (e.g., defective chips). The component 410 and the selected component 412 are held to the donor plate 408 by a release layer, and at least some of the areas of the release layer underlying the selected component 412 may be referred to as selected release layer areas. Intermittent illumination of the photobleached mask 402 (e.g., using a PCA process) projects an image of the photobleached material areas 404 of the mask through the lens 406 while blocking light incident on the photobleachable areas of the mask beyond the photobleached material areas 404 that are not bleached and contain a photobleachable compound (e.g., a photobleachable dye) that blocks the wavelength of light illuminated. The light passing through the photobleached material areas 404 illuminates the selected release layer areas located on the selected component 412, causing release (e.g., removal) of the selected component 412 (e.g., a defective chip). In some embodiments, the donor plate 408 is transparent, and illumination is directed to the release layer through the donor plate 408.To fill the resulting voids, a similar operation and assembly as shown in FIG. 4 may be performed on another donor plate, for example the donor plate shown in FIG. 1C, by using the same intermittently photobleached mask 402 to deposit components (e.g., good dice) in the areas of the donor plate 408 previously occupied by the selected components 412. The clear or photobleached area of ​​the mask does not have to correspond to exactly one chip, and in some embodiments the entire area of ​​the chip may be selected. This is valuable in non-uniform process conditions that result in out-of-specification emission wavelengths, such as for example microLEDs, that typically extend for distances longer than one LED. In some embodiments that adjust FIG. 4, the photobleached material area 404 is instead a photobleachable area, and the photobleachable area of ​​the mask beyond the photobleached material area 404 is instead a photobleached area.

[0033] The advantage of using an intermittently photobleached mask is that photobleached optical patterns can be more easily generated compared to either etched metal masks or laser ablated polymer masks. In an embodiment of the PCA process, deep ultraviolet light (e.g., 248-260 nm) is used. In addition, the intensity of the light may be adjusted to simultaneously impart the heat required for PCA. However, such optical patterns may be difficult to form on the required length scale directly from digital inputs such as LED arrays, digital micromirror devices, LCD light valves, or other spatial light modulators, most of which require longer wavelength light and may only tolerate low intensities. For example, a typical high-resolution LCD display, with, for example, up to about 1500 subpixels per inch (500 display pixels, subdivided into 3 color subpixels per display pixel), has an emitting area of ​​about 14 μm in area, which is small enough to give uniform selectivity over an area of ​​about 100 μm or less. For higher resolution, micro LED arrays may be assembled with a pixel pitch of less than 10 μm. Both of these sources are available in all visible wavelengths and may be fabricated for 365 nm applications. Alternatively, multiple scanning beams in a low density array could be fabricated using near ultraviolet or blue light sources (e.g. The defect removal method may be made by a number of light sources (LEDs or diode lasers) assembled as close together as mechanically feasible or convenient. Each individual light source may be appropriately switched on and off as the array is scanned across the donor plate, allowing for higher throughput than with a single light source. This method may be advantageous from the standpoint of production economics, despite its extra steps. The defect removal method is performed as part of the preparation of donor plates used to populate multi-chip circuits using a PCA process in which on the order of 100 (in a non-limiting example, about 100 to about 400) chips are transferred to the product target at one time. To obtain the desired economics, this step should be as fast as possible. In the PCA process, this transfer typically requires less than a millisecond and utilizes donor plates containing thousands of chips (or tens of thousands depending on chip size). The donor plates may be economically processed as described during the pre-press sequence to remove and replace defective chips, with significantly more time spent on each plate than is spent on each product target. In this manner, bleaching the mask pattern in dye using a relatively low intensity light source may be economically preferable compared to the alternatives of sequential processing with a single laser beam or fabricating a different metal mask for each defect pattern.

[0034] In some embodiments, the intermittently photobleached mask 402 (e.g., an anthracene-based selectively photobleachable dye mask) can be used directly as the basis of the optical pattern during the PCA operation without the need to fabricate a metal mask. Although metal masks have higher durability over long production runs, such metal masks are typically more difficult and time consuming to fabricate. Therefore, a metal mask with a specific mask pattern may be more suitable for use as a primary chip transfer to a product unit that is subjected to hundreds of thousands (or more) of exposures, during which the polymer may be more prone to damage. FIG. 5 shows a standard pre-press optical arrangement 500 that may be used to adjust the spacing of the columns and rows of chips. The mask 502 includes multiple apertures 504 in a single column (or row), and the mask 502 is mounted on a lens 506 (shown as a cylindrical lens) that is mounted on a donor plate 508. In some embodiments, the aperture may instead include a single open rectangular aperture instead of the multiple apertures 504. The light passes through a plurality of apertures 504 and then through a lens 506 to a donor plate 508, exposing the release layer located in a selected row of components 518, but not exposing components 510 and 512 of donor plate 508. In some embodiments, the mask remains stationary while the donor plate moves relative to the mask for each transfer to each new selected row. In the absence of a selected component (e.g., a defective chip), this rectangular mask may be the same for all chips of the type and may be used multiple times.

[0035] It may be possible to accelerate the part transfer process by using two masks (e.g., a metal mask and an intermittently photobleached mask). For example, using a metal mask and an intermittently photobleached mask may allow selected parts (e.g., defective chips) to be simultaneously removed or eliminated during a first pre-press step, such as the first pre-press step shown in FIG. 1A and FIG. 1B. An embodiment of such a double masked arrangement 600 is shown in FIG. 6. Similar to the mask shown in FIG. 5, a first mask 602 (e.g., a metal mask) is shown with a rectangular slit opening 604 that defines rows and is configured to image light onto a second mask 606 and then onto a part (e.g., chip) of a donor plate 614 to induce release and transfer of the part. In some embodiments, the slit opening 604 is a slot whose width is the same or similar to one dimension of the part (e.g., chip) being transferred. The second mask 606 includes regions 608 of photobleached material that act as apertures, and photobleachable regions 610 that are not photobleached and include a photobleachable compound (e.g., a photobleachable dye) that blocks the wavelength of light that is irradiated. The light for each row passes through the first mask 602, through the photobleached regions 608, is blocked by the photobleachable regions 610 of the second mask 606, and then through the lens 612 to the selected features 616 of the donor plate 614. In some embodiments, the second mask 606 and donor plate 614 are then moved simultaneously relative to the rectangular slit openings 604 of the first mask 602 to transfer the selected features 616 to the substrate with the new row spacing. The photobleachable regions 610 of the second mask 606 are not bleached and correspond to the locations of the non-selected features 618 (e.g., defective features) of the donor plate 614. Thus, irradiation of the release layer of the donor plate through the double mask arrangement 600 releases the release layer attached to the selected components 616 (e.g., chips) and allows the selected components 616 to be transferred, while the non-selected components 618 (e.g., defective components) remain attached to the donor plate 614 by the remaining release layer. Thus, once the selected components 616 are transferred to a second substrate (e.g., a second donor plate), the second donor plate may have a component pattern similar to the device shown in FIG. 1B. In some embodiments, the arrangements and / or processes described with respect to FIG. 4 and / or FIG. 6 may be utilized in a final pre-press transfer to fill the voids in the second substrate with the selected components 616, for example, to achieve the component distribution shown in FIG. 1C. In some embodiments of the double mask arrangement of FIG. 6, the photobleached regions 608 are instead photobleachable regions and the photobleachable regions 610 are instead photobleached regions.

[0036] Thus, by utilizing the described dual mask arrangement, at least one step of the transfer process using the selected components, e.g., the transfer method of Figures 1A-1C, may be eliminated. Although the mechanics and optics of the dual mask arrangement and the method utilizing the arrangement may be more complex (e.g., two masks, additional imaging lenses that may be required, and / or additional corresponding alignments), such an approach may advantageously improve production throughput by reducing the number of steps and thus processing time.

[0037] In some embodiments (e.g., for donor plates with relatively few defects), the photobleachable dye can be coated directly onto a metal mask to form a combination mask, hi some embodiments, the combination mask can be used for the main transfer.

[0038] In this embodiment, the defective chips are still in the donor plate that has been carried through a pre-press operation and performs the final transfer of the product units. FIG. 7 shows the donor plate 700 with the selected components 702 selected to be removed. In some embodiments, the donor plate 700 is configured to simultaneously place at least one of 36 components (e.g., chips) from each of 100 subarrays (each 3 mm×3 mm) onto 100 devices (e.g., product circuits, each 20×20 mm). The wafer from which the components (e.g., chips) were taken is assumed to have seven selected components 702 (e.g., defective). In some embodiments, the components (e.g., chips) are transferred in a certain order; (1,1), (1,2), 1,3),..., (2,1), (2,2),..., (6,6), where the numbers refer to the column and row positions within each subarray. When a selected feature (e.g., a defective chip) in the donor plate is aligned with a target location on the device, the mask that successfully selected one or more features (e.g., chips) from each subarray is pulled out and replaced by a mask (e.g., an intermittent photobleached mask or a dual mask arrangement) that has the location of the selected feature blocked, but the other locations are clear. For example, the (3,3) position of a subarray is defective in four places, so the mask switch would be performed four times for the four subarrays that can be populated by this donor plate.

[0039] In some embodiments, if the donor plate does not include selected components (e.g., defective chips) in the set or subarray that will be transferred to the device or product unit in any one exposure, a typical mask (e.g., metal slit mask) may be used. Using FIG. 7 as an example, this is true for 32 exposures, each exposure transferring 100 chips. In some embodiments, if one or more selected components (e.g., defective chips) are in a position where they can be transferred and incorporated into the product according to the defect pattern, the regular mask is removed and an intermittently photobleached mask (i.e., dye-coated mask) containing the bleached corresponding defect pattern therein is inserted and utilized so that only the non-selected components (e.g., good dice) are transferred when the release layer is exposed to light. In some embodiments, the substrate containing vacancies is then diverted into a separate flow, where it is filled by known good dice from the donor plate. In some embodiments, the mask change may be accomplished simultaneously with the substrate change, requiring only a small additional alignment time increase compared to the normal process. In some embodiments (eg, those with low defect densities), this modification may be relatively rare and therefore advantageous in the production process.

[0040] Four substrates holding components with voids at the (3,3) position may be placed in separate streams, and the voids at the (3,3) position may be filled with components from another donor plate in a finishing step. In some embodiments, the "finishing" donor locations are required to provide known good dice to fill in the voids. In some embodiments, when this is done in parallel (i.e., not with a directed laser beam), over time the donor plate becomes depleted in random locations and is no longer able to have good dice aligned with every void that is transferred in one exposure. With some reduction in throughput, the remaining chips in the depleted donor plate may be transferred using a mask with a single aperture that moves in alignment with each chip to be transferred. In some embodiments, a directed laser beam may be used. In some embodiments, these modes of operation may be combined; for example, when there are 10 voids, at one point only 9 chips are available for simultaneous transfer. These 9 may be transferred in one exposure, and the 10th void may be filled in single chip mode.

[0041] In some embodiments, the embodiments are described with reference to transferring individual rows or columns of parts (e.g., chips) in a pre-press process step, however, any number of columns / rows and / or patterns of parts may be utilized. For example, multiple columns may be transferred simultaneously, resulting in a block or sub-array of parts (e.g., chips) on the donor plate.

[0042] Although certain specific embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and modifications in the systems and methods described herein may be made without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to cover such forms or modifications as are within the scope and spirit of the present disclosure.

[0043] It should be understood that any feature, material, property, or group described in connection with a particular aspect, embodiment, or example may be applicable to other aspects, embodiments, or examples described in this section, or anywhere in this specification, to the extent not inconsistent therewith. All of the features disclosed in this specification (including any accompanying claims, abstract, and figures), and / or all of the steps of any method or process so disclosed, are incorporated herein by reference in their entirety. At least some of such features and / or steps may be combined in any combination, except combinations in which they are mutually exclusive. Protection is not limited to the details of any of the above embodiments. Protection extends to any novel or any novel combination of features disclosed in this specification (including any accompanying claims, abstract and figures), or to any novel or any novel combination of steps of any method or process so disclosed.

[0044] Moreover, certain features that are described herein in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Also, although features may be described above as acting in a particular combination, one or more features from a claimed combination may in some cases be deleted from the combination and the combination may be claimed as a subcombination or a variation of the subcombination.

[0045] Also, although operations may be shown in the figures or described in the specification in a particular order, such operations need not be performed in that particular order shown, or in sequential order, or all of these operations need not be performed to achieve a desired result. Other operations not shown or described may be incorporated into the example methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or during any of the operations described. Furthermore, operations may be rearranged or reordered in other implementations. Those skilled in the art will recognize that in some embodiments, the actual steps taken in the illustrated and / or disclosed processes may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed and others may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form further embodiments, all of which are within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the components and systems described may generally be integrated together in a single product or packaged into multiple products. For example, any of the components for the energy storage systems described herein may be provided separately or integrated together (e.g., packaged together or attached together) to form an energy storage system.

[0046] For purposes of this disclosure, certain aspects, advantages, and novel features have been described herein. Not necessarily all such advantages may be achieved by any particular embodiment. Thus, for example, one skilled in the art will recognize that the present disclosure may be embodied or performed in a manner that achieves one advantage or advantages taught herein without necessarily achieving other advantages that may be taught or suggested herein.

[0047] As used herein, conditional language, e.g., "can," "could," "might," or "may," is generally intended to convey that a particular embodiment includes certain features, elements, and / or steps while other embodiments do not, unless specifically stated otherwise or understood otherwise within the context in which it is used. As such, such conditional language should not be construed as implying that the features, elements, and / or steps are required in any respect in one or more embodiments, or that one or more embodiments do not require those features, elements, and / or steps in any particular way, whether or not input or indicated by a user. It is generally not intended to imply that any particular embodiment necessarily includes logic for determining what is included or should be implemented in a particular embodiment.

[0048] Connecting language, e.g., the phrase "at least one of X, Y, and Z," is generally used to convey that an item, term, etc. may be either X, Y, or Z, unless specifically stated otherwise, and is otherwise understood by context. As such, such connecting language is generally not intended to imply that a particular embodiment requires the presence of at least one of X, at least one of Y, and at least one of Z.

[0049] As used herein, words of degree, such as the terms "approximately," "about," "generally," and "substantially," as used herein, refer to a value, amount, or characteristic that is close to a stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," "generally," and "substantially" may refer to an amount that is within less than 10%, within less than 5%, within less than 1%, within less than 0.1%, and within less than 0.01% of the stated amount, depending on the desired function or result.

[0050] The scope of the present disclosure is not intended to be limited by the specific disclosure of preferred embodiments in this section or anywhere in this specification, but may be defined by the claims set forth or hereafter set forth in this section or anywhere in this specification, which claim language is to be interpreted broadly based on the language used in the claims and not limited to the examples described herein or during the prosecution of the application, which examples are to be interpreted as non-exclusive.

[0051] The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the devices and methods disclosed herein.

Claims

1. An intermittently photobleached mask, comprising: an intermittently photobleached layer comprising a photobleachable material; a substrate disposed on the intermittently photobleached layer; the intermittently photobleached layer includes photobleached regions that are at least partially transparent to light at a stripping wavelength; and The intermittently photobleached mask, wherein the intermittently photobleached layer includes non-photobleached regions that are substantially opaque to light at the ablation wavelength.

2. The mask of claim 1 , wherein the photobleachable material comprises a base polymer and a polycyclic aromatic hydrocarbon compound.

3. 3. The mask of claim 2, wherein the polycyclic aromatic hydrocarbon compound is selected from the group consisting of acene, tetracene, pentacene, rubrene, anthradichromene, dianthrone, and combinations thereof.

4. 3. The mask of claim 2, wherein the polycyclic aromatic hydrocarbon compound is selected from the group consisting of 9,10-dimethylanthracene (DMA), 9,10-diphenylanthracene (DPA), 1,4,9,10-tetraphenylanthracene, 5,12-diphenyltetracene, and combinations thereof.

5. 3. The mask of claim 2, wherein the polycyclic aromatic hydrocarbon compound is substituted with a substituent selected from the group consisting of alkyl, aryl, siloxane, and combinations thereof.

6. 6. The mask of claim 5, wherein the siloxane is substituted with a substituent selected from the group consisting of polyacetylene, a fluoropolymer, a polynorbornene, and combinations thereof.

7. The mask of claim 2 , wherein the base polymer comprises a polymer selected from the group consisting of acrylate polymers, siloxane polymers, and combinations thereof.

8. 8. The mask of claim 7, wherein the acrylate polymer is selected from the group consisting of poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(butyl methacrylate) (PBMA), and combinations thereof.

9. The mask of any one of claims 1 to 8, wherein the stripping wavelength is between 250 and 370 nm.

10. The mask of any one of claims 1 to 8, wherein the photobleached areas are at least 60% transparent to light at the ablation wavelength.

11. The mask of any one of claims 1 to 8, wherein the non-photobleachable areas are up to 10% transparent to light at the ablation wavelength.

12. The mask of any one of claims 1 to 8, wherein the substrate is transparent to light at the ablation wavelength.

13. A method of using an intermittently photobleached mask according to any one of claims 1 to 8, comprising the steps of: the method includes placing the intermittently photobleached mask on a transfer assembly including a donor plate, a release layer disposed on the donor plate, and a plurality of features disposed on the release layer; In the above process, the plurality of components includes at least one selected component disposed at least partially overlying at least one selected release layer region; and the photobleached area is aligned with the at least one selected release layer area; The method includes directing light at the release wavelength through the photobleached area to the at least one release layer region, thereby degrading the at least one release layer region to form at least one release part.

14. The method of claim 13 further comprising transferring the at least one released component to a receiving substrate.

15. The method of claim 13 , wherein the at least one delaminated part comprises multiple delaminated parts, and the multiple delaminated parts are transferred simultaneously to a receiving substrate.

16. 14. The method of claim 13, further comprising directing the ablation wavelength light through a second mask onto the photobleached area.

17. 17. The method of claim 16, wherein the second mask prevents exposure of further photobleached areas of the intermittently photobleached mask to light at the ablation wavelength.

18. after directing the ablation wavelength light through the second mask, moving the second mask relative to the intermittently photobleached mask and the transfer assembly; The method of claim 16 , wherein the relative positions of the intermittently photobleached mask and the transfer assembly are the same.

19. The method of claim 13 further comprising applying heat to the at least one release layer region.

20. The method of claim 13 , wherein the light at the exfoliation wavelength is directed through the substrate to the at least one exfoliation layer region.

21. 1. A method for making an intermittently photobleached mask, comprising: providing a photobleachable layer disposed on a substrate, the photobleachable layer being opaque to light at a stripping wavelength; exposing the photobleachable layer to an atmosphere comprising oxygen gas; and irradiating selected areas of the photobleachable layer to form an intermittently photobleached layer including photobleached areas that are at least partially transparent to light at the stripping wavelength. The method comprising:

22. 22. The method of claim 21 further comprising depositing the photobleachable layer on the substrate.

23. 23. The method of claim 21 or 22, wherein the atmosphere is air or an oxygen-rich atmosphere.

24. The method according to claim 21 or 22, wherein the irradiation is carried out at a photobleaching wavelength of 250 to 550 nm.

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