JP7134095B2 - Precision shadow mask deposition system and method - Google Patents

Description

(Related application)
This application claims priority to U.S. Provisional Patent Application No. 62/340,793 (Attorney Docket Number: 6494-208PR1) filed May 24, 2016, which is incorporated herein by reference. be It is also U.S. Provisional Patent Application No. 15/597,635 filed May 17, 2017 (Attorney Docket Number: 6494-208US1) and U.S. Provisional Patent Application No. 15/597,635 filed May 23, 2017 Priority is claimed to Application No. 15/602,939 (Attorney Docket No. 6494-209US1), both of which are incorporated herein by reference.

This invention relates generally to thin film deposition, and more particularly to evaporation-based thin film deposition.

Shadow mask-based deposition is a process in which a layer of material is deposited onto the surface of a substrate such that a desired pattern of the layer is defined during the deposition process itself. This is a deposition technique also called "direct patterning".

In a typical shadow mask deposition process, the desired material is vaporized from a source remote from the substrate with the shadow mask positioned therebetween. As the vaporized atoms of the material travel toward the substrate, they pass through a set of through-holes in the shadow mask located just in front of the substrate surface. The through-holes (ie, openings) are arranged in a pattern suitable for the material on the substrate. As a result, the shadow mask blocks the passage of all vaporized atoms except those that pass through the through-holes, and the atoms that pass through the through-holes are deposited on the substrate surface in the desired pattern. Shadow mask-based deposition is similar to the silkscreen technique used to form patterns (eg, jersey numbers, etc.) on clothing and stenciled products used in artwork development.

Shadow mask-based deposition has long been used in integrated circuits (ICs) to deposit patterns of material on a substrate, in part due to the fact that it avoids the need to pattern a layer of material after it has been deposited. has been used in industry. As a result, its use eliminates the need to expose the deposited material to harsh chemicals (eg, acid-based etchants, corrosive photolithography development chemicals, etc.) to pattern the material. In addition, shadow mask-based deposition requires less substrate handling and processing, thereby reducing the risk of substrate damage and increasing manufacturing yields. Additionally, many materials, such as organic materials, cannot be exposed to photolithography chemicals without damaging them, which requires depositing such materials through a shadow mask.

Unfortunately, the feature resolution obtained by conventional shadow mask deposition is reduced due to the tendency of deposited material to spread laterally after passing through the shadow mask, referred to as "feathering." Feathering increases as the distance between the substrate and the shadow mask increases. To mitigate feathering, this spacing is made as small as possible without compromising the integrity of the chuck holding the substrate and shadow mask. Furthermore, this non-uniformity of separation across the deposition area causes variations in the amount of feathering. Such non-uniformity can result, for example, from lack of parallelism between the substrate and the shadow mask, bowing or sagging of one or both of the substrate and shadow mask, and the like.

Unfortunately, it is difficult to place the shadow mask and substrate close enough so that a significant amount of feathering does not occur. Furthermore, the shadow mask must be supported only at its perimeter so as not to impede the passage of vaporized atoms into the through-hole pattern. As a result, the center of the shadow mask can sag under gravity, which further exacerbates the feathering problem.

In practice, therefore, the critical features formed by prior art shadow mask-based deposition techniques are typically separated by relatively large areas of open space to accommodate feathering, resulting in device densities of is restricted. For example, each pixel in an active matrix organic light emitting diode (AMOLED) display typically includes multiple regions of organic light emitting material, each emitting a different color of light. Due to feathering issues, prior art AMOLED displays are typically limited to about 600 pixels per inch (ppi) or less, which is a limitation for many applications such as near-eye augmented reality and virtual reality applications. is insufficient for the use of In addition, the large gaps within and between pixels are required, which reduces the pixel fill factor and reduces the brightness of the display. As a result, the current density through the organic layers must be increased to provide the desired brightness, which can adversely affect the lifetime of the display.

Another method deposits a monochrome white light emitting organic layer over the entire display using a shadow mask with openings as large as the active area of the display itself, then red, green and blue over the OLEDs. patterning or depositing color filters. These color filters are capable of absorbing all emitted white light except the red, green or blue portion of the spectrum (depending on the color filter) and creating a full color image. However, these color filters absorb up to 80% of the emitted light, significantly reducing the brightness of the display and again requiring operation at higher than desirable drive currents.

There remains an unmet need in the prior art for processes that enable high resolution direct patterning.

The present invention enables high-resolution direct deposition of patterned layers of material onto a substrate without some of the costs and disadvantages of the prior art. Embodiments of the present invention filter the propagation angles of vaporized atoms to a narrow range around the direction normal to the surface of the substrate. As a result, feathering of material deposited outside the lateral dimension of the shadow mask topography is reduced. Embodiments of the invention are particularly well suited for use in the deposition of photosensitive materials such as organic light emitting materials. Embodiments are also well suited for the deposition of other thin and thick layers in packaging applications, integrated circuit processing applications, and the like.

The present invention also allows for high precision alignment of the shadow mask and substrate, which can be in contact or separated by only a few microns. The present invention also provides a reduction in gravitationally induced sag of a shadow mask that is supported only at its perimeter. Embodiments of the present invention are particularly well suited for applications requiring dense patterns of material on a substrate, such as high density pixel displays (DPDs), high definition displays, and the like.

An exemplary embodiment of the invention is a direct patterning deposition system in which material is vaporized at a source such that the material is deposited on the surface of the substrate after passing through the pattern of openings in the shadow mask. Before reaching the shadow mask, the vaporized atoms pass through a collimator, which blocks all vaporized atoms except those with propagation angles near the normal to the substrate surface. As a result, the lateral displacement between the openings and their respective deposited material regions is reduced compared to the prior art.

The collimator includes a plurality of channels with high aspect ratios, with longitudinal axes of the channels substantially aligned with the normal direction. As a result, those vaporized atoms traveling along directions other than the near-normal direction are shielded by the inner walls of the channel.

In some embodiments, the source is sized and positioned to provide a conical vapor plume of vaporized atoms such that the entire substrate surface receives vaporized material simultaneously. In some of these embodiments, the source is moved along the path so that thickness uniformity of the deposited material is improved over a two-dimensional area of the substrate surface.

In some embodiments, the source is a linear source that emits a fan-shaped vapor plume, the linear source moving along a direction that is not aligned with its longitudinal axis. In some of these embodiments, the source is moved along a direction substantially orthogonal to both the longitudinal axis and the normal direction of the source. In some of these embodiments, the source moves along a non-linear path.

In some embodiments, the source includes a plurality of individual nozzles, each nozzle having a respective cone-shaped vapor stream to collectively provide a substantially uniform flow of vaporized atoms over an area of the substrate surface. emit a plume.

In some embodiments, the source is a two-dimensional planar source positioned parallel to and facing the substrate such that when heated, the organic material vaporizes uniformly over the plane of the source. In some embodiments, relative motion between the source and shadow mask is provided to improve thickness uniformity of the deposited material over a two-dimensional area of the substrate surface.

Another exemplary embodiment of the invention includes a first chuck having a first mounting surface for holding a substrate and a second mounting surface for holding a shadow mask containing a pattern of through holes. and a second chuck having a direct patterning deposition system. A second chuck includes a frame surrounding a central opening that exposes the pattern of through-holes in the shadow mask. As a result, during deposition, vaporized atoms of the material can pass through the second chuck and through-holes and deposit in a desired pattern on the deposition area on the front side of the substrate.

A first chuck generates a first electrostatic force selectively applied to the back surface of the substrate. The first chuck is also sized and positioned so as not to protrude beyond the front surface of the substrate. Similarly, a second chuck generates a second electrostatic force selectively applied to the backside of the shadow mask. The second chuck is also sized and positioned so as not to protrude beyond the front surface of the shadow mask. When the shadow mask and substrate are aligned for deposition, neither portion of the first and second chucks encroach on the three-dimensional space between the substrate and shadow mask. As a result, the substrate and shadow mask can be placed in very close proximity or even touching during deposition, thereby mitigating feathering.

In some embodiments, at least one of the first attractive force and the second attractive force is a non-electrostatic force such as a vacuum generating force, a magnetic force, or the like.

In some embodiments, the second mounting surface is sized and arranged to create a tensile stress in the front surface of the shadow mask to reduce gravity sag in its central region. In some such embodiments, the frame of the second chuck is shaped such that its mounting surface slopes away from the upper edge of the inner circumference of the frame. As a result, when the shadow mask is mounted on the second chuck, the shadow mask bends slightly, creating a tensile stress on the front surface of the shadow mask. In some of these embodiments, the mounting surface curves downward from the top edge of the inner perimeter of the frame.

One embodiment of the invention is a system for depositing a first material on a plurality of deposition sites in a deposition region of a substrate, the plurality of deposition sites arranged in a first arrangement, the substrate comprising: , a first major surface and a second major surface including the deposition region, wherein the system is a source for supplying a first plurality of vaporized atoms of the first material, the first one plurality of vaporized atoms each propagating along a propagation direction characterized by a propagation angle relative to a first direction perpendicular to a first plane defined by the substrate; a source, wherein a range of propagation angles of vaporized atoms of the vaporized atoms of the source extends over the first angular range; and a plurality of through holes arranged in the first arrangement, the shadow mask comprising the through holes a shadow mask including three major surfaces and a fourth major surface; and a first chuck for holding the substrate, dimensioned to selectively impart a first attractive force to the first major surface. a fixedly positioned first chuck and a second chuck for holding the shadow mask, allowing the material to pass through the second chuck to a through hole. a second chuck comprising a frame surrounding the first opening and dimensioned and arranged to selectively impart a second attractive force to the third major surface; and a plurality of channels; A collimator between the source and the shadow mask, each of a plurality of channels passing only vaporized atoms having propagation angles within a second angular range less than the first angular range. and a positioning system for controlling the relative positions of the first chuck and the second chuck for aligning the shadow mask and the substrate, sized and arranged to and is a system comprising

Another embodiment of the invention deposits a first material on a plurality of deposition sites in a deposition region of a substrate, said plurality of deposition sites being arranged in a first arrangement, said substrate having a first lateral A system including a first major surface and a second major surface having a directional length, a source supplying a first plurality of vaporized atoms, each of the first plurality of vaporized atoms moves along a propagation direction defining a propagation angle, said plurality of propagation angles spanning a first angular range, said shadow comprising a source and a plurality of through holes arranged in said first arrangement. a mask, wherein the shadow mask includes a third principal surface and a fourth principal surface including the through holes, and the shadow mask and the plurality of deposition sites are jointly smaller than the first angular range; A shadow mask, a first chuck for holding the substrate, and a second chuck for holding the shadow mask, defining an acceptable angular range, wherein the material extends into the second chuck through the through hole. a frame surrounding a first opening to allow passage through the chuck of the shadow mask and the substrate when the shadow mask and substrate are aligned to jointly define a first region; , the first region (1) having a second lateral length greater than or equal to the first lateral length and (2) equal to the spacing between the substrate and the shadow mask. (3) excluding the first chuck and the second chuck, allowing the first chuck and the second chuck to be less than 10 microns thick; and said collimator comprising a plurality of channels, each of said plurality of channels defining a filtering angular range that is less than or equal to said acceptable angular range. A collimator having an aspect ratio.

Yet another embodiment of the present invention is a method for depositing a first material on a plurality of deposition sites arranged in a first arrangement on a substrate, the substrate having a first lateral length a first major surface and a second major surface having a height, the second major surface comprising the first region, the method comprising a source and a source arranged in the first arrangement; receiving a first plurality of vaporized atoms with a collimator positioned between the shadow mask having a plurality of through holes, the shadow mask having a third major surface including the through holes and a fourth major surface including the through holes; a first chuck comprising a major surface, wherein said first plurality of vaporized atoms is characterized by a first range of propagation angles; and selectively applying a first attractive force to said first major surface. and holding the shadow mask on a second chuck that selectively exerts a second attractive force on the third major surface, the second chuck comprising the third and selectively passing a second plurality of vaporized atoms through the collimator to the shadow mask. wherein the second plurality of vaporized atoms are characterized by a second range of propagation angles narrower than the first range of propagation angles; positioning the substrate and the shadow mask such that the surfaces are separated by a distance of 10 microns or less; and C. allowing deposition on the substrate through the holes.

1 is a schematic cross-sectional view of salient features of a direct patterning deposition system according to the prior art; FIG. FIG. 4 shows a schematic cross-sectional view of salient features of a precision direct patterning deposition system, according to an exemplary embodiment of the invention. 4 illustrates operation of a method for depositing a patterned layer of material directly onto a substrate, according to an exemplary embodiment; FIG. 4 shows a schematic diagram of a top view of a mask chuck according to an exemplary embodiment; FIG. 4 shows a schematic diagram of a cross-sectional view of a mask chuck in accordance with an exemplary embodiment; A cross-sectional view of the shadow mask 106 mounted on the mask chuck 206 is shown. FIG. 4 shows a schematic representation of a cross-sectional view of a portion of mask chuck 206 according to a first alternative embodiment of the present invention. FIG. 4B shows a schematic diagram of a cross-sectional view of a portion of mask chuck 206 according to a second alternative embodiment of the present invention. Fig. 3 shows a schematic diagram of a top view of a mask chuck according to a third alternative embodiment of the present invention; Figure 3 shows a schematic representation of a cross-sectional view of a mask chuck according to a third alternative embodiment of the present invention; FIG. 4 shows a schematic diagram of a cross-sectional view of a mask chuck in accordance with an exemplary embodiment; FIG. 4 shows a schematic illustration of a cross-sectional view of substrate chuck 204 while holding substrate 102 . FIG. 4 shows a schematic representation of a cross-sectional view of a portion of system 100 with substrate 102 and shadow mask 106 aligned for deposition of material 116 . FIG. 2 shows a schematic diagram of a magnified view of the pixel area of the substrate 102 and the corresponding opening 120 of the shadow mask 106. FIG. FIG. 4 shows a schematic diagram of a cross-sectional view of a collimator according to an exemplary embodiment; FIG. 4 shows a schematic diagram of a top view of the area of the collimator 208. FIG. FIG. 4 shows a schematic diagram of a cross-sectional view of the area of the collimator 208. FIG.

FIG. 1 shows a cross-sectional schematic of salient features of a direct patterning deposition system according to the prior art. System 100 is a conventional deposition system that deposits a desired pattern of material on a substrate by evaporating the material through a shadow mask placed in front of the substrate. System 100 includes source 104 and shadow mask 106 positioned within a low pressure vacuum chamber (not shown).

Substrate 102 is a glass substrate suitable for forming an active matrix organic light emitting diode (AMOLED) display. Substrate 102 includes a surface 114 that defines a plane 108 and a normal axis 110 . Normal axis 110 is orthogonal to plane 108 . Surface 114 has a plurality of deposition sites G for receiving green light-emitting materials, a plurality of deposition sites B for receiving blue light-emitting materials, and a plurality of red light-emitting materials. includes a plurality of deposition sites R of The deposition sites are arranged in a plurality of pixel areas 112 such that each pixel area contains one deposition site for each color of light-emitting material.

Source 104 is a crucible for vaporizing material 116, which is an organic material that emits light of the desired wavelength. In the illustrated example, material 116 is an organic light emitting material that emits red light. In the illustrated example, source 104 is a single-chamber crucible centered with respect to substrate 102 . However, in some embodiments, source 104 comprises multiple chambers arranged in a one-dimensional and/or two-dimensional arrangement. As material 116 melts or sublimates within the low pressure atmosphere of vacuum chamber 110 , vaporized atoms 122 of material 116 are emitted from the source and propagate toward substrate 102 substantially ballistically. Vaporized atoms emitted from source 104 collectively define vapor plume 124 .

Shadow mask 106 is a plate of structural material that includes openings 120 . The shadow mask is generally flat and defines plane 118 . A shadow mask is placed between the source 104 and the substrate 102 such that it blocks the passage of all vaporized atoms except those through its openings. The shadow mask and substrate are separated by a separation distance s (typically tens or hundreds of microns), planes 108 and 118 are substantially parallel, and opening 120 is aligned with deposition site R. there is

Ideally, when depositing the red emitting material 116, the vaporized atoms are only incident on the deposition sites R. Unfortunately, the vapor plume 124 contains vaporized atoms traveling along many different propagation directions 126 , many of which are not aligned with the direction of the normal axis 110 . As a result, most of the vaporized atoms passing through opening 120 are traveling along the propagation direction with a large lateral component. The point at which each vaporized atom impinges on surface 114 is geometrically defined by its propagation angle and the spatial relationship between the substrate and the shadow mask, specifically the spacing s and the positional relationship between opening 120 and deposition site R. is determined by For the purposes of this specification, including the appended claims, the term "propagation angle" is the direction perpendicular to the plane 108 of the substrate 102 (i.e., the normal direction 128, which is the normal axis 110 and is defined as the angle formed by the direction of propagation of vaporized atoms with respect to For example, vaporized atoms 122 move along propagation direction 126 and produce a propagation angle θp with respect to normal direction 128 .

The propagation angles of the vaporized atoms of the vapor plume 124 span a relatively wide angular range from -θm to +θm, which poses a significant disadvantage for prior art direct deposition systems. In particular, it causes deposition of material 118 on the outer front surface 114 around the opening 120, which is typically referred to as "feathering." Furthermore, the amount of feathering at an opening increases with the distance of that opening from the center of substrate 102 .

For an aperture located near the center of vapor plume 124, vaporized atoms 122 reaching shadow mask 106 have propagation angles within a relatively small range of angles. In other words, they are moving along directions that are slightly offset from the normal axis 110 . As a result, vaporized atoms passing through these openings exhibit only minimal lateral drift (feathering) after passing through the shadow mask. Thus, in this region, the lateral length of deposition material 116 is typically substantially aligned with the edge of opening 120 (ie, it deposits primarily at target deposition site R).

However, for openings further away from the center of the vapor plume 124, the vaporized atoms reaching the shadow mask 106 are spread over a relatively wide range of angles, including propagation angles close to |θm|. As a result, in these regions, vaporized atoms travel a greater lateral distance after passing through the shadow mask, causing the deposited material to feather far beyond the lateral extent of the opening. . This creates a lateral offset Δf between the edge of the aperture opening and the perimeter of the area where material 116 is deposited. Thus, the deposited material extends beyond the target deposition area. In some cases, such feathering can result in deposition of material onto adjacent deposition sites intended for different emissive materials (i.e., deposition sites, B and/or G), thereby causing color mixing. be.

deviations from parallelism of surfaces 108 and 118 (i.e., relative pitch and/or yaw between mask and substrate), shadow mask and/or substrate unflatness, and between shadow mask and substrate; Note that any additional misalignment between the shadow mask and the substrate, such as translational and/or rotational misalignment, will exacerbate feathering. Moreover, in many prior art deposition systems (eg, systems for depositing multiple materials, etc.), the source 104 is positioned off-center from the substrate, which creates even greater feathering problems.

Those skilled in the art will recognize that placing the shadow mask 106 in contact with the substrate 102 during deposition may reduce or even completely eliminate the feathering problem. Unfortunately, this is often undesirable or impossible for several reasons. First, prior art substrate and shadow mask chucks typically include features that protrude above the substrate and shadow mask, respectively. As a result, these features act as shielding elements that limit how close the substrate and shadow mask can be placed. Second, contact with the shadow mask can damage existing structures on the substrate surface. Third, shadow mask damage can occur from contact with the substrate. Fourth, residue can remain on the shadow mask surface upon removal from contact with the substrate. Frequent cleaning of the shadow mask is required, increasing processing time and overall cost, while potentially damaging the mask during cleaning operations. As a result, prior art shadow mask deposition has been substantially limited to non-contact configurations where feathering has significant adverse effects. Fifth, conventional shadow masks are typically made of metal and are therefore necessarily quite thick. When placed in contact with the substrate, the thick shadow mask causes shadowing within each opening area, resulting in thin edges of the deposited features. With thicker shadow masks, such as those commonly used in the prior art, more material is lost due to thinner aperture walls and sub-pixel edges.

However, the present invention allows direct deposition without some of the disadvantages of the prior art. A first aspect of the present invention significantly reduces feathering by allowing only vaporized atoms propagating along directions substantially perpendicular to the surface of the substrate to reach the shadow mask, thereby reducing the openings in the shadow mask. To allow patterns of deposited material with higher resolution and fidelity to the pattern.

Another aspect of the present invention is that the use of non-metallic materials such as silicon nitride for the shadow mask allows it to be extremely thin (≤1 micron), thereby significantly reducing the shading of prior art shadow masks. It is to become.

Yet another aspect of the present invention is that gravity-induced sag of the shadow mask can be reduced or eliminated by using a shadow mask chuck that is sized and positioned to counteract the effects of gravity on the shadow mask. .

Another aspect of the present invention is a substrate and shadow mask chuck having no structures protruding above the top surface of the substrate and shadow mask, allowing very small separation, even contact, between the substrate and the shadow mask, This is to reduce feathering. The substrate/shadow mask contact also increases their stability during deposition, improves material utilization by reducing waste, allows faster deposition and higher throughput, and allows deposition at lower temperatures. to

FIG. 2 shows a schematic cross-sectional view of salient features of a precision direct patterning deposition system, according to an exemplary embodiment of the invention. System 200 includes vacuum chamber 202 , substrate chuck 204 , source 104 , shadow mask 106 , mask chuck 206 , collimator 208 and positioning system 212 . System 200 operates to deposit a desired material pattern on a substrate surface without requiring subsequent subtractive patterning operations such as photolithography and etching.

System 200 is described herein with respect to depositing a pattern of light-emitting material onto a glass substrate as part of manufacturing an AMOLED display. However, after reading this specification, the present invention will provide a substantial It will be apparent to those skilled in the art that the method can be directed to forming directly patterned layers of any thin and thick film material (organic or inorganic). Further, although the exemplary embodiment is a thermal evaporation system, one of ordinary skill in the art, after reading this specification, will recognize that the present invention can be directed to virtually any material deposition process, such as electron beam evaporation, sputtering and sputtering. Recognize that. Furthermore, although the illustrated example is a deposition system suitable for use in single substrate planar processing, the invention is applicable to other manufacturing processes such as cluster tool processing, track processing, roll-to-roll processing, reel-to-reel processing, and the like. Also suitable for use in methods. As a result, the present invention is suitable for use in myriad applications including, but not limited to, packaging applications, IC manufacturing, MEMS manufacturing, nanotechnology device manufacturing, ball grid array (BGA) manufacturing, and the like.

In the illustrated example, shadow mask 106 is a precision shadow mask that includes a handle substrate 224 and membrane 226, with membrane 226 suspended over a central opening formed in the handle substrate. Membrane 226 includes a through-hole pattern 228 . Shadow mask 106 includes two major surfaces, front surface 230 and back surface 232 . Front surface 230 is the top surface of membrane 226 (ie, the membrane surface distal to steering substrate 224 ), which defines plane 118 . Back surface 232 is the surface of steering substrate 224 (ie, the substrate surface distal to membrane 226). Note that the shadow mask 106 is a high precision film-based shadow mask, but the mask chuck according to the invention can be used to hold virtually any type of shadow mask. Preferably, membrane 226 comprises silicon nitride. However, other materials can be used without departing from the scope of the invention. Preferably, membrane 226 has a thickness of 1 micron or less. However, other thicknesses can be used for the membrane without departing from the scope of the invention.

As noted above, the use of shadow mask films having a thickness of 1 micron or less can reduce shadowing effects during direct deposition compared to prior art shadow masks.

Vacuum chamber 202 is a conventional pressure vessel for containing the low pressure environment required for deposition of material 116 . In the illustrated example, vacuum chamber 110 is a stand-alone unit. However, it can also be implemented as part of a cluster deposition system or track deposition system in which a plurality of deposition chambers are arranged in a line without departing from the scope of the invention. In some embodiments, the vacuum chamber 110 has several layers that enable the formation of different patterns of different materials on the substrate 102, such as multiple emissive sub-pixels that emit light in different colors (e.g., red, green, and blue). Including some vapor source/shadow mask combinations.

Controller 240 is a conventional instrument controller that, among other things, provides control signals 236 and 238 to substrate chuck 204 and mask chuck 206, respectively.

FIG. 3 illustrates method operations for depositing a patterned layer of material directly onto a substrate, according to an exemplary embodiment. 4A-4B, 5, 6A-6B, 7A-7B, 8A-8B, 9, 10 and 11A, with continued reference to FIG. Described herein with reference to FIG. 11C. Method 300 begins at operation 301 where collimator 208 is mounted on collimator chuck 210 .

Collimator 208 is a mechanically robust plate containing multiple channels separated by thin walls, as described in more detail below and with respect to FIGS. 11A-11C. Collimator 208 is sized and positioned to act as a spatial filter to selectively pass vaporized atoms propagating along directions substantially perpendicular to plane 108 (i.e., having very small propagation angles). . Collimator 202 thus reduces feathering across substrate 102 .

Collimator chuck 210 is an annular clamping mechanism for holding and positioning the collimator relative to shadow mask 106 .

In operation 302 , shadow mask 106 is loaded onto mask chuck 206 .

Mask chuck 206 is a fixture for holding shadow mask 106 via suction applied only to its back surface. In the illustrated example, mask chuck 206 holds shadow mask 106 using electrostatic forces. In some embodiments, the mask chuck 206 holds the shadow mask using various attractive forces such as vacuum forces, magnetic forces, and the like. In other embodiments, mask chuck 206 is a mechanical clamp.

4A and 4B show schematic diagrams of top and cross-sectional views, respectively, of a mask chuck according to an exemplary embodiment. The cross-section shown in FIG. 4B is taken from line aa shown in FIG. 4A. Mask chuck 206 includes frame 402 , electrodes 404 - 1 and 404 - 2 and pads 406 .

Frame 402 is a structurally rigid circular ring of electrically insulating material. Frame 402 surrounds an opening 408 large enough to expose the entire through-hole pattern 228 . In some embodiments, frame 402 has a shape other than circular, such as square, rectangular, or irregular. In some embodiments, frame 402 comprises a conductive material coated with an electrical insulator.

Electrodes 404 - 1 and 404 - 2 are conductive elements formed on the surface of frame 402 . Electrodes 404 - 1 and 404 - 2 are electrically coupled to controller 240 .

Pad 406 is a structurally rigid plate of electrically insulating material disposed over electrodes 404-1 and 404-2. Each of pads 406 includes a mounting surface 410 on which shadow mask 106 is held when mounted on a mask chuck.

FIG. 5 shows a cross-sectional view of shadow mask 106 mounted on mask chuck 206 .

Shadow mask 106 is held on mask chuck 206 by electrostatic forces applied between mounting surface 410 and back surface 232 . An electrostatic force is generated in response to the potential between electrodes 401-1 and 404-2 generated by control signal 238. FIG. When the back surface 232 contacts the mounting surface 410, a resonant charge region is generated within the operating substrate 224, as shown. As a result, an electrostatic force is selectively applied between back surface 232 and mounting surface 410 .

Shadow mask 106 is typically supported only at its perimeter. As a result, prior art shadow masks tend to sag under gravity. In some embodiments, mask chucks according to the present invention include one or more features that reduce or eliminate gravity-induced sagging of the shadow mask when the shadow mask is mounted. As detailed above, the shadow mask may sag several microns in the center due to its own mass and gravitational effects. This gravity-induced sag creates several important problems that exacerbate feathering. First, it increases the distance between the shadow mask and the substrate, usually in the middle of the deposition area centered on the shadow mask. As mentioned above, feathering increases with the substrate/shadow mask separation distance. Second, it results in a non-uniform separation between the substrate and the shadow mask, which causes variations in the degree of feathering that occur across the substrate surface. Non-uniformity makes it difficult, if not impossible, to correct for feathering with creative mask placement.

Yet another aspect of the present invention is that the mask chuck can include features that reduce gravity-induced sag of the shadow mask.

In some embodiments, the mask chuck 206 includes a slight curvature (eg, an upward slope) that biases the shadow mask upward to counteract shadow mask sag due to gravity. In some embodiments, a microsupport structure can extend across the opening of the mask chuck 206 to support the mask and reduce sagging due to gravity. These features are described in more detail below with respect to Figures 6A and 6B and Figures 7A and 7B.

Figure 2 shows a schematic representation of a cross-sectional view of part of a mask chuck according to a first alternative embodiment of the present invention; The cross-section shown in FIG. 6A is taken from line aa shown in FIG. 4A. Mask chuck 600 includes frame 402 , electrodes 404 - 1 and 404 - 2 and pads 702 .

Pad 602 is similar to pad 406 described above. However, each pad 602 has a mounting surface designed to induce or increase tensile strain on the shadow mask when it is mounted on the mask chuck. The pad 602 has a mounting surface 604 that tapers linearly downward from an inner edge 606 (ie, the edge closer to the opening 408 ) to an outer edge 608 . In other words, mounting surface 604 extends in the negative z-direction from point 614 to point 616 (ie, where it intersects inner edge 606 at plane 610 to where it intersects outer edge 608 at plane 612), as shown. tapering off at Thus, in embodiments where inner edge 606 is perpendicular to plane 610, inner edge 606 and mounting surface 604 create an interior angle θ such that it is an acute angle.

When the shadow mask 106 is held in the mask chuck 600, the back surface 232 is drawn toward the mounting surface 604, thereby causing shadow mask curvature that increases the lateral tension of the front surface 230 of the shadow mask. As a result, the membrane is pulled tighter and gravity-induced sag is reduced or eliminated.

FIG. 6B shows a schematic diagram of a cross-sectional view of a portion of a mask chuck according to a second alternative embodiment of the invention. The cross-section shown in FIG. 6B is taken from line aa shown in FIG. 4A. Mask chuck 618 includes frame 402 , electrodes 404 - 1 and 404 - 2 and pads 720 .

Pad 620 is similar to pad 406 described above. However, like pads 602, each pad 620 has a mounting surface designed to create or increase tensile strain on the shadow mask when it is mounted on the mask chuck. Pad 620 has a mounting surface 622 that curves downward (ie, in the negative z-direction as shown) from inner edge 606 to outer edge 608 . In other words, mounting surface 622 tapers in the negative z direction from point 614 to point 616 as shown.

When the shadow mask 106 is held in the mask chuck 618, the back surface 232 is drawn toward the mounting surface 622, thereby causing a curvature within the shadow mask that increases the lateral tension of the front surface 230 of the shadow mask. As a result, the membrane is pulled tighter and gravity-induced sag is reduced or eliminated. In some embodiments, the amount of additional tension created in front surface 230 can be controlled by controlling the magnitude of the voltage difference applied to electrodes 404-1 and 404-2.

After reading this specification, it will be apparent to those skilled in the art that in a deposition system in which the mask is mounted upside down compared to its orientation shown in FIG. ) is reversed. Further, in such a configuration, substrate chuck 204 would typically need to be designed so that substrate 102 resides within opening 408 and allow a substrate/shadow mask separation of 10 microns or less. .

7A and 7B show schematic top and cross-sectional views, respectively, of a mask chuck according to a third alternative embodiment of the present invention. Mask chuck 700 includes mask chuck 206 and support grid 702 .

Support grid 702 includes plates 704 and support ribs 706 .

Plate 704 is a rigid plate from which support ribs 706 extend. In some embodiments, plate 704 and support ribs 706 are machined from a solid body of structural material. Materials suitable for use in plate 704 and support ribs 706 include, but are not limited to, metals, plastics, ceramics, composites, glass, and the like. Plate 704 is designed to be attached to frame 402 to position support grid 702 within opening 408 to mechanically support membrane 226 when shadow mask 106 is attached to mask chuck 700 . It is

The support ribs 706 are arranged to support the shadow mask 106 in areas between the through-holes of the through-hole arrangement 228 . Typically, the shadow mask through-holes are arranged in clusters corresponding to different die regions on the substrate. Since these die areas are typically separated by "lanes" intended for removal by a dicing saw, the support ribs 706 are preferably arranged to match the arrangement of these lanes. However, it should be noted that any suitable arrangement of support ribs can be used for support grid 702 .

The support grids 702 are formed such that their upper surfaces 708 are coplanar and define a plane 710 . Plane 710 lies above mounting surface 410 at a distance equal to the thickness of control board 224 . As a result, when the operating substrate 224 contacts the mounting surface 410 , the support ribs 706 contact the membrane 226 .

In some embodiments, shadow mask 106 is held upside down in mask chuck 700 such that membrane 226 is in contact with mounting surface 410 . In such embodiments, support grid 702 is designed to fit within opening 408 such that flat surface 710 is coplanar with mounting surface 410 . As a result, membrane 226 is supported by support grid 702 so that it is perfectly horizontal across opening 408 .

In operation 303 the substrate 102 is mounted on the substrate chuck 204 .

Substrate chuck 204 is a platen for holding substrate 102 using an attractive force applied only to its back surface. In the illustrated example, substrate chuck 204 generates an electrostatic force to hold the substrate. However, in some embodiments, the substrate chuck 204 holds the substrate using various attractive forces such as vacuum forces, magnetic forces, and the like. For the purposes of this specification, including the appended claims, the term "magnetic force" includes any force resulting from the use of permanent magnets and/or electromagnets. Substrate chuck 204 is described in more detail below with respect to FIGS. 8A and 8B.

In some embodiments, substrate chuck 204 is sized and positioned to contact substrate 102 only from the front surface to reduce interference with material deposition on the opposite side of the substrate. In some embodiments, the substrate chuck 204 secures the substrate using various means such as vacuum, mechanical clamping, etc. from both sides of the substrate. In some embodiments, substrate chuck 204 includes an in-situ gap sensor that works with positioning system 212 to control the spacing and parallelism between substrate 102 and shadow mask 106 .

In the illustrated example, substrate 102 is a glass substrate suitable for use in active matrix organic light emitting diode (AMOLED) displays. The substrate 102 includes two major surfaces, a back surface 115 and a front surface 114, on which display elements are defined. Front surface 114 defines plane 108 .

FIG. 8A shows a schematic diagram of a cross-sectional view of a substrate chuck in accordance with an exemplary embodiment. Substrate chuck 204 includes platen 802 and electrodes 804-1 and 804-2.

Platen 820 is a structurally rigid platform that includes substrate 806 and dielectric layer 808 . Substrate 806 and dielectric layer 808 are each made of glass, ceramic, anodized aluminum, or the like, which electrically insulates electrodes 804-1 and 804-2 from each other and from substrate 102 when the substrate is mounted on a substrate chuck. Composites, including electrical insulating materials such as bakelite.

Electrodes 804-1 and 804-2 are conductive elements formed on the surface of substrate 806 and overcoated by dielectric layer 808 to embed them within platen 802. FIG. Electrodes 804 - 1 and 804 - 2 are electrically coupled to controller 240 . Note that electrodes 804-1 and 804-2 are drawn as simple plates. However, in practice, the substrate chuck 204 can have electrodes of any shape, such as interdigitated comb fingers, concentric rings, irregular shapes, and the like.

Dielectric layer 808 is a structurally rigid glass layer disposed over electrodes 804 - 1 and 804 - 2 to create mounting surface 810 .

FIG. 8B shows a schematic diagram of a cross-sectional view of substrate chuck 204 while holding substrate 102 .

To hold substrate 102 to substrate chuck 204, control signal 236 develops a potential between electrodes 804-1 and 804-2. When back surface 115 contacts mounting surface 810 (ie, the top surface of dielectric layer 808), a resonant charge region is generated in substrate 102, as shown. As a result, an electrostatic force is selectively applied to back surface 115 , thereby attracting it to mounting surface 610 .

Exemplary embodiments include a substrate chuck that uses electrostatic forces to hold the substrate 114, but after reading this specification it will be appreciated that the substrate may be chucked using attractive forces other than electrostatic forces, such as vacuum forces, magnetic forces, or the like. It will be clear to those skilled in the art how to identify, make and use the alternative embodiments held in .

In operation 304 , the relative positions of substrate 102 , source 104 , shadow mask 106 and collimator 208 are controlled by positioning system 212 .

Positioning system 212 aligns substrate 102 and shadow mask 106 by controlling the position of substrate chuck 204 . In some embodiments, the positioning system aligns the substrate and shadow mask by controlling the position of mask chuck 206 . In some embodiments, the positions of both chucks are controlled to align the substrate and shadow mask. Operation 304 and positioning system 212 are described in more detail below with respect to FIGS. 1, 2, 9, 10 and 11A-11C.

The positioning system includes three 6-axis manipulators and an optical alignment system for controlling alignment between substrate 102 and shadow mask 106 . Each of the six-axis manipulators is operatively connected to each of substrate chuck 204, mask chuck 206 and collimator chuck 210 to control its position along each of the x-, y- and z-axes and rotation thereabout. do. In some embodiments, the position of at least one of mask chuck 206 and collimator chuck 210 is not controlled by a 6-axis positioner. In some embodiments, positioning system 212 also includes a rotation stage for controlling relative rotational alignment between substrate 102 and shadow mask 106 .

In operation 304, deposition site R of deposition region 216 is aligned with opening 120, planes 108 and 118 are parallel, and spacing s between the substrate and the shadow mask is near zero (i.e., touching). ), preferably within a few microns (eg, 1 to 5 microns), the positioning system 212 positions the substrate and shadow mask. In some embodiments, s is another suitable separation distance. Note that the spacing s is drawn larger than typical for clarity.

It is an aspect of the present invention that, in some embodiments, neither substrate chuck 204 nor mask chuck 206 include any structural elements that protrude beyond their respective mounting surfaces. As a result, the substrate and shadow mask can be aligned with little or no separation between them to mitigate feathering during deposition. Those skilled in the art will appreciate that in conventional direct deposition systems, the spacing between the substrate and the shadow mask must be at least tens and even hundreds of microns.

FIG. 9 shows a schematic diagram of a cross-sectional view of a portion of system 100 with substrate 102 and shadow mask 106 aligned for deposition of material 116 .

When the substrate and shadow mask are aligned, they jointly define a region 902 therebetween. Region 902 has a lateral length L1, which is equal to the length of front surface 114 . Region 902 also has a thickness equal to the spacing s1 between planes 108 and 118 (ie, the spacing between the substrate and the shadow mask).

Since no portion of substrate chuck 204 extends beyond plane 108 into region 902, there is no obstruction between the substrate and the shadow mask. As a result, the spacing s1 between the substrate 102 and the shadow mask 106 can be extremely small (≤10 microns). In fact, the substrate and shadow mask can be brought into contact with each other, if desired. The ability to perform direct patterning at substrate/shadow mask spacings of 10 microns or less is a direct advantage of the prior art, as it enables feathering to be significantly reduced or even eliminated in embodiments of the present invention. It is particularly advantageous over patterned deposition systems. In some embodiments, there is no or zero gap between the substrate and the shadow mask to completely eliminate feathering.

At operation 305 , source 104 produces vapor plume 124 . As explained above, with respect to FIG. 1, the propagation angle θp of the vaporized atoms of vapor plume 124 spans a relatively wide angular range from −θm to +θm. In the prior art, this large angular range exacerbates feathering, which affects the lateral and rotational alignment between the substrate 102 and the shadow mask 106, the spacing s between them, and the incidence on the shadow mask. is a function of the range of propagation angles of vaporized atoms.

However, in the present invention, the range of propagation angles of vaporized atoms reaching the substrate surface is reduced by placing a spatial filter (ie, collimator 208 ) in their path from source 104 to shadow mask 106 . Thus, including collimator 208 in system 200 significantly reduces feathering during direct deposition.

FIG. 10 shows a schematic diagram of a magnified view of the pixel area 112 of the substrate 102 and the corresponding opening 120 of the shadow mask 106 . As shown, for perfect fidelity between opening 120 and deposition of material at deposition site R, the propagation angle of vaporized atoms through shadow mask 106 has a tolerance range of -θa to +θa. must be within For the purposes of this specification, including the appended claims, the term "acceptable angular range" is defined as the range of propagation angles through which the shadow mask is desired to pass, which is from -θa to +θa. spans a range of angles. Generally, the allowable range of angles is the range of angles that allows material 116 to deposit only at deposition sites R after passing through opening 120 . In some embodiments, the acceptable angular range includes a small guard band around the deposition sites to allow feathering that is less than half the spacing between the nearest deposition sites. Vaporized atoms incident on the shadow mask with propagation angles outside this range are deposited on surface 114 beyond the lateral extent of deposition site R. FIG.

At operation 306 , vapor plume 124 is filtered by collimator 208 to produce vapor column 214 .

FIG. 11A shows a schematic diagram of a cross-sectional view of a collimator in accordance with an exemplary embodiment; Collimator 208 includes a body 1102 patterned to form a plurality of channels 1104 , each extending through the thickness of body 1102 .

The main body 1102 is a glass plate suitable for planar processing. In the illustrated example, body 1102 has a thickness of approximately 25 millimeters (mm). However, any practical thickness can be used without departing from the scope of the invention. In some embodiments, body 1102 comprises various structurally rigid materials suitable to withstand the heat and/or temperatures associated with electron beam deposition without significant deformation. Materials suitable for use in body 1102 include, but are not limited to, semiconductors (eg, silicon, silicon carbide, etc.), ceramics (eg, alumina, etc.), composite materials (eg, carbon fiber, etc.), glass fibers, printed materials, and the like. Including circuit boards, metals, polymers (eg, polyetheretherketone (PEEK), etc.), and the like.

Channels 1104 are through holes formed in body 1102 using conventional machining operations such as metal forming, drilling, electron discharge machining, deep reactive ion etching (DRIE), and the like. In the illustrated example, channel 1104 has a circular cross-section with a diameter of approximately 3 mm. Therefore, the aspect ratio of channel 1104 is approximately 8:1. Preferably, the aspect ratio is at least 3:1. Furthermore, when the aspect ratio exceeds 100:1, the flow of vaporized atoms through the collimator begins to decrease to undesirable levels. However, height aspect ratios greater than 100:1 are within the scope of the present invention. In some embodiments, channel 1104 has a non-circular cross-sectional shape (eg, square, rectangular, hexagonal, octagonal, irregular, etc.).

The formation of channels 1104 results in multiple walls 1106 existing between the channels. Preferably, wall 1106 is as thin as possible without sacrificing the structural integrity of body 1102 to allow for high throughput. In the illustrated example, wall 506 has an average thickness of approximately 500 microns. However, any practical thickness can be used for wall 1106 .

11B and 11C show schematic diagrams of top and cross-sectional views, respectively, of the collimator 208 region. Channels 1106 are arranged in a honeycomb arrangement in which the rows are periodic and adjacent rows are offset by half a period from their neighbors. In some embodiments, channels are arranged in various arrangements, such as two-dimensional periodic, hexagonal close-packed, and random.

As shown in FIG. 11C, the aspect ratio of channel 1104 defines the filtering angular range. For the purposes of this specification, including the appended claims, the term "filtering angular range" is defined as the range of propagation angles that will pass through the collimator 208, which ranges from -θc to +θc. reach. As a result, vaporized atoms with propagation angles larger than |θc| will be intercepted by the collimator.

Those skilled in the art will recognize that the dimensions provided above for body 1102, channel 1104 and wall 1106 are merely exemplary and other dimensions may be used without departing from the scope of the invention.

At operation 307 , opening 120 allows the vaporized atoms of vapor column 214 to pass through to deposit on deposition site R of deposition region 216 .

In optional operation 308 , positioning system 212 imparts motion to collimator 208 to improve uniformity of vaporized atom density across the lateral length of vapor column 214 , thereby increasing deposition over the deposition site on substrate 102 . Improve uniformity. In some embodiments, positioning system 212 operates to impart an oscillatory motion to collimator 208 .

Note that source 104 is effectively a point source of material 116 because, in the exemplary embodiment, the open area of its crucible is much smaller than the area of substrate 102 .

In optional operation 309, positioning system 212 moves source 102 in the xy plane relative to the substrate to improve deposition uniformity.

In some embodiments, source 104 is a linear deposition source that includes multiple nozzles that emit a fan-shaped vapor plume of vaporized atoms. In some embodiments, the positioning system 212 provides linear feed along directions that are not aligned with its longitudinal axis in the xy plane to improve the uniformity of the material deposited on the substrate 102. move the source. In some embodiments, this path is a line substantially orthogonal to both the linear arrangement of nozzles and the normal axis 110 . In some embodiments, a linear source moves along a non-linear path in the xy plane.

In some embodiments, the source 104 includes a two-dimensional arrangement of nozzles, each nozzle having a plurality of nozzles collectively providing a substantially uniform stream of vaporized atoms over an area of the substrate surface. Each emits a cone-shaped vapor plume to effect. In some embodiments, positioning system 212 moves nozzles in a two-dimensional arrangement to promote uniformity of deposition. In some embodiments, the two-dimensional arrangement of nozzles is rotated in-plane to promote uniformity of deposition.

In some embodiments, the source 104 is a two-dimensional planar source that includes a layer of material 116 distributed over its upper surface. The source is positioned so that its upper surface is parallel to and faces the substrate 102 . Upon heating, material 116 vaporizes uniformly across the plane. Exemplary planar deposition sources suitable for use in embodiments of the present invention are described in Tung et al., "OLED Fabrication by Using Novel Planar Deposition Techniques," Int. J. of Photoenergy, Vol. ), pp. 1-8 (2014)), which is incorporated herein by reference.

In some embodiments, to improve the uniformity with which material 116 is deposited over a two-dimensional area of surface 114, positioning system 212 provides a supply by moving at least one of a substrate/mask combination and a supply source. Relative motion is provided between the source 104 and the substrate 102 and shadow mask 106 combination.

This specification merely teaches some embodiments in accordance with the invention, and many variations of the invention can be readily devised by those skilled in the art after reading this specification, and that the invention It should be understood that the scope of is determined by the following claims.

100 system 102 substrate 104 source 106 shadow mask 108 plane 110 normal axis 112 pixel area 114 surface 115 back 116 material 118 plane 120 aperture 122 vaporized atoms 124 vapor plume 126 direction of propagation 128 normal 200 system 202 vacuum chamber 204 206 mask chuck 208 collimator 210 collimator chuck 212 positioning system 214 vapor column 216 deposition region 224 operating substrate 226 membrane 228 through-hole pattern 230 front surface 232 rear surface 236 control signal 238 control signal 240 controller 402 frame 404-1 electrode 404-2 electrode 406 pad 408 opening 410 mounting surface 600 mask chuck 602 pad 604 mounting surface 606 inner edge 608 outer edge 610 plane 612 plane 614 points 616 points 618 mask chuck 620 pad 622 mounting surface 700 mask chuck 702 support grid 704 plate 706 support rib 7108 upper surface Plane 802 Platen 804-1 Electrode 804-2 Electrode 806 Substrate 808 Dielectric Layer 810 Mounting Surface 902 Region 1102 Body 1104 Channel 1106 Wall

Claims (11)

A system for depositing a first material on a plurality of deposition sites in a deposition region of a substrate, the plurality of deposition sites arranged in a first arrangement, the substrate having a first major surface and the including a second major surface including a deposition region;
said system
a source for supplying a first plurality of vaporized atoms of said first material, each of said first plurality of vaporized atoms being perpendicular to a first plane defined by said substrate; a source propagating along a propagation direction characterized by a propagation angle with respect to a first direction of , wherein the range of propagation angles of the first plurality of vaporized atoms spans a first angular range;
A shadow mask including a plurality of through holes arranged in the first arrangement, the shadow mask comprising:
(i) a control substrate having a first thickness, a central opening and a third major surface; and
(ii) a membrane suspended over said central opening, said membrane comprising a fourth major surface comprising said through hole;
a shadow mask comprising
a first chuck for holding the substrate, the first chuck being sized and arranged to selectively impart a first attractive force to the first major surface;
a second chuck for holding the shadow mask, comprising a frame surrounding a first opening that allows the material to pass through the second chuck to the through-hole; when the shadow mask is held in the second chuck, the frame defines a second plane, surrounds the first opening, and includes a mounting surface in contact with the third major surface; The second chuck includes a support grid within the first opening, the support grid comprising a plurality of support ribs, each of the plurality of support ribs extending a distance equal to the first thickness. It has an upper surface lying in a third plane away from the second plane, and when the shadow mask is mounted on the second chuck, the support ribs extend through the central opening to mechanically move the membrane. a second chuck that positively supports the
A collimator between said source and said shadow mask comprising a plurality of channels, each of said plurality of channels having a propagation angle within a second angular range less than said first angular range. a collimator sized and positioned to pass only vaporized atoms;
a positioning system for controlling the relative positions of the first and second chucks to align the shadow mask and the substrate;
A system with 3. The system of claim 1, wherein said frame is circular. 2. The system of claim 1, wherein the plurality of deposition sites and the plurality of through holes collectively define an acceptable angular range, and wherein the second angular range is less than or equal to the acceptable angular range. 2. The system of claim 1, wherein each of said plurality of channels is characterized by an aspect ratio of 8:1 or greater. 2. The system of claim 1, wherein said positioning system is operable to impart relative motion between said substrate and said collimator. The first chuck, the second chuck and the positioning system jointly align the substrate and the shadow mask such that the distance between the substrate and the shadow mask is greater than 0 microns and less than or equal to 10 microns. 2. The system of claim 1, which enables The mounting surface extends between a first edge proximate the first opening and a second edge distal to the first opening, wherein the mounting surface and the first intersects at a point in the second plane, the mounting surface and the second edge intersect at a point in the fourth plane, and the shadow mask and the substrate are aligned , wherein the second plane is closer to the substrate than the fourth plane. A method for depositing a first material on a plurality of deposition sites arranged in a first arrangement of a substrate, the substrate having a first major surface having a first lateral length and a first major surface having a first lateral length. comprising two major surfaces, the second major surface comprising the deposition sites;
said method comprising:
providing a shadow mask including a plurality of through holes, the shadow mask comprising:
(i) a control substrate having a first thickness, a central opening and a third major surface; and
(ii) a membrane suspended over the central opening, the membrane having a fourth major surface including the plurality of through holes;
providing a shadow mask, comprising
holding the substrate on a first chuck that selectively exerts a first attractive force on the first major surface;
holding the shadow mask to a second chuck that selectively exerts a second attractive force on the third major surface, the second chuck moving the plurality of the a frame having a first opening to allow movement of vaporized atoms of the material to the through-holes, the frame opening into the first opening when the shadow mask is held in the second chuck; having a mounting surface surrounding a portion and defining a first plane and in contact with the third major surface, the second chuck including a support grid within the first opening, the support grid comprising: a plurality of support ribs, each of said plurality of support ribs having an upper surface lying in a second plane separated from said first plane by a distance equal to said first thickness; 2, said support ribs extend through said central opening and mechanically support said membrane;
positioning the substrate and the shadow mask such that the second major surface and the fourth major surface are separated by a distance of 10 microns or less;
receiving a first plurality of vaporized atoms at a collimator located between a source and the shadow mask, the first plurality of vaporized atoms characterized by a first range of propagation angles; stages and
selectively passing a second plurality of vaporized atoms through the collimator to the shadow mask, wherein the first plurality of vaporized atoms comprises the second plurality of vaporized atoms; a plurality of vaporized atoms of 2 characterized by a second range of propagation angles narrower than the first range of propagation angles;
allowing at least a portion of the second plurality of vaporized atoms to pass through the second chuck and the plurality of through holes and deposit onto the substrate;
A method, including further comprising providing the collimator to include a plurality of channels, each of the plurality of channels having an aspect ratio that determines the second range of propagation angles, the aspect ratio being an acceptable 9. The method of claim 8, based on a range of possible angles, said acceptable range of angles being defined by said substrate and said shadow mask. 9. The method of claim 8, wherein the substrate and shadow mask are aligned such that the second major surface and the fourth major surface are separated by a distance greater than 0 microns and less than or equal to 10 microns. The mounting surface extends between a first edge proximate the first opening and a second edge distal to the first opening, wherein the mounting surface and the first intersects at a point in the first plane, the mounting surface and the second edge intersect at a point in the third plane, and the shadow mask and the substrate are aligned 9. The method of claim 8, further comprising providing the second chuck such that the first plane is closer to the substrate than the third plane.

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