Systems and methods for direct patterning using compensated shadow masks

Abstract

A system and method are presented for directly patterning a material on a substrate with high fidelity to a desired pattern. A pattern of openings in a shadow mask is compensated to accommodate a range of propagation angles in a vapor plume used to deposit material onto a substrate through the shadow mask. A shadow mask according to the present disclosure includes an opening pattern in which the opening positions are shifted inward toward the center of the shadow mask by an amount based on the distance of the opening from the center of the shadow mask. As a result, evaporated material passing through an opening at a non-perpendicular angle is deposited on the substrate in its correct, desired location.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 404,076, filed September 6, 2022 (Attorney Docket No. 6494-241PR1), which is incorporated by reference as if set forth in its entirety herein. If there is any conflict or inconsistency in language between this application and one or more of the cases incorporated by reference that may affect the interpretation of a claim in that case, the claim in that case shall be construed consistent with the language in that case.

[0002] FIELD OF THE DISCLOSURE This disclosure relates generally to material deposition, and more particularly to direct patterning of a layer of material on a substrate via deposition of the material onto the substrate through a shadow mask. [Background technology]

[0003] Semiconductor manufacturing requires the formation of a single or patterned layer of material on the surface of a substrate. The most common approach to forming a material pattern is to deposit a blanket layer of material over the entire surface of the substrate and then use an etchant to remove the material everywhere except where desired. This is commonly referred to as "subtractive patterning."

[0004] Unfortunately, many materials cannot be patterned using subtractive patterning because they are attacked by the chemicals required for the process. Therefore, for such materials, a direct patterning process must be used. In a direct patterning process, the reactive material is vaporized, and the vapor passes through openings (i.e., apertures) in a shadow mask and is deposited on a substrate located behind the shadow mask, thereby forming the desired pattern in one step.

[0005] Historically, shadow mask deposition has been used in semiconductor manufacturing to define patterns of relatively large (>50 microns) features that do not require high precision or pattern fidelity, such as wire bond pads. A typical shadow mask used in such applications includes a thin, patterned metal sheet held by an annular frame. While the minimum feature size and minimum spacing between openings for such shadow masks are very large (typically greater than tens of microns), such shadow masks are perfectly suitable for defining large feature sizes and sparse patterns of material, such as wire bond pad patterns.

[0006] More recently, shadow mask deposition has become ubiquitous in the formation of active matrix displays based on organic light-emitting diodes (OLEDs). However, as such displays have evolved to ever higher resolutions, a need has arisen to form patterns of organic materials with at least one dimension of only a few microns. For example, microdisplay resolution is rapidly improving as more advanced methods make it possible to pattern OLED subpixels with smallest dimensions of less than 3.5 microns. Subpixel dimensions of 2 microns or less are expected in the near future. Recent success in the direct patterning of OLED microdisplays with red, green, and blue subpixels formed side-by-side can be credited to the development of advanced high-resolution shadow masks as thin as 1 micron and apertures on the scale of a few microns.

[0007] In theory, during shadow mask deposition, material is deposited only on the surface of the substrate in the area directly behind the opening. However, in reality, the evaporated material travels from the source to the shadow mask as a non-parallel plume. As a result, much of the vapor propagates along a direction that is not perfectly perpendicular to the shadow mask and substrate.

[0008] Furthermore, the substrate is typically separated from the shadow mask by a small gap to prevent damage to either or both of the shadow mask and substrate and to allow for active alignment thereof. Summary of the Invention [Problem to be solved by the invention]

[0009] Non-parallel vapor plumes combined with the spacing between the shadow mask and the substrate create at least two undesirable effects. The first, called "shadowing," occurs when the evaporated material arrives at an angle to the substrate and deposits on an area smaller than the desired outline of the subpixel. The second, called "feathering," occurs when the evaporated material passes through the shadow mask at an angle and continues to migrate laterally beyond the edge of the opening through which it passed. The magnitude of this feathering is a function of the separation distance between the substrate surface and the shadow mask, which is preferably very small, at most a few microns, as well as the orientation of the source relative to the center of the shadow mask.

[0010] While shadowing and feathering are not significant issues when forming large, widely spaced features (e.g., wire bond pads, etc.), they can become very problematic when forming dense patterns of small features. In fact, feathering has been the limiting factor for the minimum feature size and pattern density obtainable using shadow mask deposition.

[0011] The ability to form high resolution patterns of small, closely spaced features with high pattern fidelity using shadow mask deposition would be a welcome advancement in the state of the art. [Means for solving the problem]

[0012] The present disclosure relates to an apparatus and method that enables direct patterning of a material layer on a substrate via shadow mask deposition with reduced shadowing and feathering compared to what can be achieved in the prior art by employing a shadow mask whose opening pattern is compensated based on the geometry of the deposition system in which the shadow mask is used. Embodiments according to the present disclosure are particularly well suited for use in manufacturing organic light emitting diodes (OLEDs), OLED displays, organic photovoltaic cells, and the like.

[0013] An advancement over the prior art is realized by compensating the pattern of openings in a shadow mask to adjust the range of propagation angles in a vapor plume used to deposit material onto a substrate through the shadow mask. In contrast to prior art in which opening locations in a shadow mask are perfectly aligned with the desired location of material deposition, embodiments according to the present disclosure include shadow masks in which opening locations are shifted in at least one lateral direction based on the distance of the opening from the center of the shadow mask and, in some cases, further based on the lateral offset between the center of the shadow mask and the center of the evaporation source. In the absence of such a lateral offset, the location of each opening is shifted inward toward the center of the shadow mask by an amount based on the distance of that opening from the center of the shadow mask. Such opening shifts allow evaporated material passing through each opening at a non-perpendicular angle to be deposited on the substrate in its proper location.

[0014] An exemplary embodiment includes a source of evaporative material, a shadow mask, and a substrate chuck for holding a target substrate. The target substrate, shadow mask, and source are centered on a central axis. The source provides a vapor plume that expands laterally as it advances toward the target substrate, resulting in the evaporative material propagating toward the substrate along a wide range of angles. The shadow mask has a two-dimensional pattern of apertures, some or all of which are laterally shifted in at least one dimension relative to the desired locations of their corresponding subpixels on the substrate, to form a two-dimensional pattern of subpixels on the target substrate. The lateral shift of each aperture relative to its corresponding desired subpixel location is based on the location of the aperture, the spacing between the shadow mask and the substrate, and the throw distance between the source and the substrate.

[0015] An embodiment according to the present disclosure is a system for directly depositing a material onto a substrate, the system comprising: a source for providing an evaporative substance; and a shadow mask having a plurality of openings arranged in a first pattern having a center point, wherein adjacent openings along the first dimension are spaced apart by a distance that monotonically decreases with distance from the center point along the first dimension, the shadow mask configured for placement between the source and the substrate.

[0016] Another embodiment according to the present disclosure is a method for depositing a material on a substrate, the method including vaporizing a first material and passing the vaporized first material through a shadow mask onto the substrate, the shadow mask having a plurality of openings arranged in a first pattern having a center point, wherein adjacent openings along a first dimension are spaced apart by a distance that monotonically decreases with distance along the first dimension from the center point. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of an exemplary embodiment of a shadow mask deposition system according to the prior art; [Figure 2A] 1 is a schematic diagram of an ideal relationship between a shadow mask and a wafer according to the prior art; [Figure 2B]1 is a schematic diagram of an ideal relationship between a shadow mask and a wafer according to the prior art; [Figure 3] 1 is a schematic diagram of a typical relationship between a shadow mask and a wafer according to the prior art. [Figure 4] 1 is a schematic diagram of the basic geometry of a prior art direct deposition system. [Figure 5A] 4 is a plot of the relationship between the width of the shadow region 402 and the size of the gap g. [Figure 5B] 4 is a plot of the relationship between the width of the feather region 404 and the size of the gap g. [Figure 6A] 1 is a table showing the width (in the x-direction) of the shadow region 402 for a desired sub-pixel location 202(i) as a function of gap size g and lateral distance R from the center of the source 102. [Figure 6B] 10 is a table showing the width (in the x-direction) of the feather region 404 for a desired sub-pixel location 202(i) as a function of gap size g and lateral distance R from the center of the source 102. [Figure 7] FIG. 1 is a schematic diagram of an exemplary embodiment of a shadow mask deposition system according to the present disclosure. [Figure 8] FIG. 1 is a schematic diagram of the relationship between shadow mask openings and their corresponding sub-pixel locations on a wafer, in accordance with the present disclosure. [Figure 9] 1 is a schematic diagram of the basic geometry of a direct deposition system according to the present disclosure. [Figure 10] 1 is a top view schematic diagram of a shadow mask having a two-dimensional arrangement of apertures that are compensated in two dimensions, according to the present disclosure; DETAILED DESCRIPTION OF THE INVENTION

[0018] 1 depicts a schematic diagram of an exemplary embodiment of a prior art shadow mask deposition system. System 100 includes a source 102, a shadow mask 104, a mask chuck 106, and a substrate chuck 108. System 100 is a conventional vertical direct deposition system for forming a material pattern 112 on a substrate 110.

[0019] Typically, the components of a vertical direct deposition system are enclosed in a conventional pressure vessel that provides a low-pressure environment that supports the direct deposition of material pattern 112 .

[0020] Source 102 is a crucible for vaporizing material 116 to create vapor plume 118. In the depicted example, material 116 is an organic material suitable for use in OLEDs, and source 102 acts as a virtual point source for the evaporated material because the open area of ​​the crucible is significantly smaller than the area of ​​substrate 110.

[0021] Shadow mask 104 is an element including a layer of structural material having a plurality of openings arranged in an opening pattern 114, where the size and placement of the openings is based on the desired deposition pattern for material 116. The surface of shadow mask 104 near substrate 118 defines plane P1.

[0022] The mask chuck 106 is a mechanical clamp that positions the shadow mask 104 between the source 102 and the substrate 110 .

[0023] Substrate chuck 108 is a platen for securing substrate 110 so that the substrate is as flat as possible.

[0024] Substrate 110 is a glass substrate suitable for supporting planar process-based manufacturing of OLED displays. In some embodiments, substrate 118 is a different conventional substrate suitable for planar processing, such as a semiconductor wafer (e.g., silicon, gallium arsenide, indium phosphide, etc.), a composite substrate, etc. The surface of substrate 110 near shadow mask 104 defines plane P2.

[0025] In operation, the source 102, shadow mask 104, and substrate 110 are aligned so that they are approximately concentric along a vertical axis A1, the shadow mask and substrate are parallel and separated along the vertical axis by a gap g (typically tens or hundreds of microns), and the shadow mask openings are aligned with their respective desired deposition locations on the substrate 110. In the depicted example, planes P1 and P2 are each approximately perpendicular to the vertical axis A1 (i.e., θ=90°).

[0026] When heated, source 102 melts material 116, generating vapor plume 118. As discussed above, vapor plume 118 comprises material vapor propagating along directions spanning a relatively large range of angles. As a result, the vaporized atoms travel some lateral distance after passing through the openings in the shadow mask, resulting in feathering and shadowing of material 116 at desired subpixel locations in material pattern 112.

[0027] The amount of feathering and shadowing that occurs is determined by the lateral and rotational alignment between planes P1 and P2, the size of the gap g between them, and the range of propagation angles in the vapor plume 118.

[0028] 2A-2B depict a schematic diagram of the ideal relationship between a shadow mask and a wafer according to the prior art.

[0029] In arrangement 200, desired subpixel locations 202 are linearly arranged along the x-axis such that subpixel location 202(0) is located at the center of substrate 110 such that the subpixel locations are centered on axis A1, subpixel locations 202(1) through 202(4) are equidistantly spaced to the right of subpixel location 202(0) such that adjacent subpixels have a center-to-center spacing s1, and subpixel locations 202(-1) through 202(-4) are equidistantly spaced to the left of subpixel location 202(0) such that adjacent subpixels have a center-to-center spacing s1.

[0030] In the prior art, each of the apertures 204 of the shadow mask 104 is aligned with its corresponding desired pixel location 202. As a result, the apertures 204 are also linearly arranged along the x-axis, such that aperture 204(0) is located at the center of aperture pattern 114 so that it is centered on axis A1, apertures 204(1) through 204(4) are spaced equidistantly to the right of aperture 204(0) so that adjacent apertures are spaced apart by spacing s, and apertures 204(-1) through 204(-4) are spaced equidistantly to the left of aperture 204(0) so that adjacent apertures are spaced apart by spacing s.

[0031] FIG. 3 depicts a schematic diagram of a typical relationship between a shadow mask and a deposited material pattern on a wafer according to the prior art.

[0032] In contrast to what is depicted in Figures 2A-2B, in reality, the size of the gap g combined with the range of angles about the propagation direction of the evaporated material in the vapor plume 118 results in a monotonic increase in the spacing between the deposited regions 302 of material 116 as the position of each deposited region increases from the center of the substrate 110.

[0033] As a result, each deposited region 302 is offset from its respective desired sub-pixel location 202 by an amount that increases uniformly with that sub-pixel's distance from axis A1.

[0034] For example, for a given value of g and a given range of angles of the propagation direction of evaporated material 116, the center-to-center spacing between each pair of adjacent deposited regions 302 experiences a monotonically increasing δ as the positions of these deposited regions move outward along the x-direction. As a result, even though the central deposited region 302(0) is perfectly aligned with the central desired subpixel location 202(0) along the x-direction, moving outward along the x-direction from the central axis A1, each successive deposited region 302 is shifted outward by δ from the previously deposited region. As a result, for example, deposited region 302(1) is shifted outward by δ from subpixel location 202(1), deposited region 302(2) is shifted outward by 2δ from subpixel location 202(2), and so on.

[0035] 4 depicts a schematic diagram of the basic geometry of a prior art direct deposition system. In configuration 400, aperture 204(i) is perfectly aligned with desired sub-pixel location 202(i). The center of the aperture and sub-pixel location is located a distance R from axis A1, which is aligned with the center of source 102.

[0036] The top surface of shadow mask 104 defines plane P3, and the bottom surface of substrate 110 defines plane P4. Planes P1 and P2 are parallel and spaced apart by a distance g. Furthermore, shadow mask 104 has a thickness of M, and the bottom surface of substrate 110 (i.e., plane P2) is at a throw distance H from source 102.

[0037] Subpixel location 202(i) corresponds to a subpixel having width Dx, which is the distance between points x01 and x02, which is equal to the width w of aperture 204(i).

[0038] During deposition of material 116, the evaporated material reaches substrate 110 at angles ranging from θ1 to θ2 after passing through opening 204(i). Due to gap g, the evaporated material fails to reach substrate 110 in the region between positions x01 and X1, thereby defining shadow region 402.

[0039] Additionally, material 116 is deposited in the area between points x02 and X2, which is the region beyond the desired subpixel location, thereby defining feather region 404. It should be noted that the incidence angles θ1 and θ2 depend on the size of the gap g, the mask thickness M, and the throw-in distance H. The important parameters of arrangement 400 can be described by the following equations: Dx=x02-x01 (1) x01=Rs / 2 (2) X02=r+s / 2 (3) h1=HGM (4) h2=HG (5) tanθ1=x01 / h1 (6) tanθ2=x02 / h2 (7)

[0040] Using equations (1) through (7), the sizes of the shadow region 402 and feather region 404 can be determined for different separation distances g between the substrate 110 and the shadow mask 104. Table 1 below lists the widths (in the x-direction) of the shadow region 402 and feather region 404 for the desired sub-pixel location 202(i) for R=90 mm.

[0041] [Table 1]

[0042] Table 1 shows the width of the shadow region 402 and feather region 404 for various values ​​of gap g.

[0043] 5A-5B depict plots of the relationship between the width of the shadow region 402 and the feather region 404, respectively, and the size of the gap g.

[0044] 6A-6B depict tables showing the widths (in the x-direction) of the shadow region 402 and feather region 404 for a desired sub-pixel location 202(i) as a function of gap size g and lateral distance R from the center of the source 102. Table 2 shows the effect of gap size g and distance R on the width of the shadow region 402. Table 3 shows the effect of gap size g and distance R on the width of the feature region 404.

[0045] It should be noted that while shadow and feather regions of such sizes may potentially be acceptable in large format displays having subpixel dimensions of about several hundred microns, high resolution microdisplays have subpixel dimensions of only a few microns and therefore cannot tolerate such a lack of pattern fidelity. In microdisplays, such shadowing and feathering effects can result in subpixels not being completely covered by the deposited material and / or intermixing of subpixels, resulting in reduced brightness and / or poor color rendition.

[0046] However, it is an aspect of the present disclosure that better pattern fidelity can be realized by compensating the placement of the shadow mask openings so that the opening locations are offset from their respective desired subpixel locations by a distance based on their distance from the center of the target substrate. In other words, in accordance with the teachings herein, shadowing and feathering in the presence of a mask-to-wafer gap of several microns can be reduced by laterally shifting the shadow mask features based on the geometry of the deposition system.

[0047] 7 depicts a schematic diagram of an exemplary embodiment of a shadow mask deposition system according to the present disclosure. System 700 includes source 102, shadow mask 702, mask chuck 106, and substrate chuck 108. System 700 is a vertical direct deposition system for forming a material pattern 706 on substrate 110.

[0048] Shadow mask 702 is similar to shadow mask 104 described above, except that shadow mask 702 includes a compensated aperture pattern 704 .

[0049] In compensated aperture pattern 704, the placement of apertures is compensated to account for the range of propagation angles in vapor plume 118. As a result, every aperture will not be perfectly aligned with its corresponding desired deposition location.

[0050] FIG. 8 depicts a schematic diagram of the relationship between the shadow mask openings and their corresponding sub-pixel locations on the wafer, according to the present disclosure.

[0051] In arrangement 800, apertures 802 are shifted laterally along the x-axis relative to their corresponding sub-pixel locations, such that aperture 802(0) is perfectly aligned with sub-pixel location 202(0), which is located in the center of substrate 110 and centered on axis A1, and apertures 802(1) and 802(-1) are slightly shifted toward axis A1 relative to sub-pixel locations 202(1) and 202(-1), respectively, such that apertures 802(2) and 802(-1) are perfectly aligned with sub-pixel location 202(0), which is located in the center of substrate 110 and centered on axis A1. Apertures 802(-2) and 802(-2) are shifted slightly further toward axis A1 relative to subpixel locations 202(2) and 202(-2), respectively, apertures 802(3) and 802(-3) are shifted further toward axis A1 relative to subpixel locations 202(3) and 202(-3), respectively, and apertures 802(4) and 802(-4) are shifted the most toward axis A1 relative to subpixel locations 202(4) and 202(-4), respectively. The amount of lateral shift applied to each aperture is based on its position relative to the center of aperture pattern 704, the size of gap g, and throw distance H, as discussed below with respect to FIG. 9 .

[0052] 2 and 3, for illustrative purposes, an exemplary shadow mask according to the present disclosure will now be described for a substrate having subpixel locations with a fixed center-to-center distance s, and the same given value of g and a range of angles for the propagation direction of evaporated material 116. Using these parameters, employing a shadow mask 702 having a center-to-center distance s between adjacent openings 802 that decreases by δ along the x-direction away from central axis A1 enables deposition of material 116 on subpixels 202 with high pattern fidelity and minimal feathering. For example, along the x-direction, when shadow mask 702 is aligned with substrate 110, opening 802(0) is aligned with central subpixel location 202(0), and the center-to-center distance between adjacent openings decreases by δ for each successive pair of adjacent openings. As a result, along the positive x-direction, openings 802(0) and openings 802(1) have a center-to-center distance of s-δ, openings 802(2) and openings 802(1) have a center-to-center distance of s-2δ, openings 802(3) and openings 802(2) have a center-to-center distance of s-3δ, and so on.

[0053] It should be noted that while the depicted example involves uniformly indexed shifts in aperture position, a wide variety of lateral shifts (e.g., non-uniform, non-linear variations, variations according to a mathematical function f(x), etc.) are within the scope of this disclosure. Furthermore, in some embodiments, the subpixel or pixel locations are not uniformly spaced center-to-center, and therefore the required compensation shift is adjusted accordingly. Still further, in some embodiments, the source 102, shadow mask 702, and substrate 110 are not concentric during deposition. In such embodiments, the compensation applied to aperture 802 includes additional factors to account for this lack of concentricity.

[0054] 9 depicts a schematic diagram of the basic geometry of a direct deposition system according to the present disclosure. In arrangement 900, apertures 802(i) are laterally shifted relative to their corresponding desired subpixel locations 202(i) by δx, which is determined from the location of that subpixel relative to the center of the substrate 110, as well as the gap g1 and throw-in distance H. The value of δx for each aperture can be determined using equations (1) through (7).

[0055] Using a shadow mask compensated in accordance with the present disclosure, evaporative material 116 is deposited over the desired sub-pixel locations (ie, between points x01 and x02).

[0056] As the desired subpixel location moves away from the center of the substrate 110 (i.e., axis A1), angles θ3 and θ4 gradually increase from zero to several degrees. As a result, δx must also gradually increase to reduce shadowing and feathering, thereby achieving near-complete material coverage of the desired subpixel location.

[0057] The specific value of δx for a given sub-pixel position is calculated based on the angle of incidence θ3, which in turn depends on the sub-pixel position from the substrate center (i.e., distance R), the throw distance H, and the mask-to-wafer gap g1. It should be noted that the mask-to-wafer gap is typically pre-defined and must be kept constant during deposition for a given shadow mask with gradually shifted openings (which are also typically pre-designed).

[0058] Thus far, for ease of explanation, the discussion of compensated shadow masks has been in the context of a one-dimensional lateral shift (i.e., along the x-direction), however, those skilled in the art will appreciate that typical OLED manufacturing processes are based on shadow masks with a two-dimensional array of apertures.

[0059] 10 depicts a schematic diagram of a top view of a shadow mask having a two-dimensional arrangement of apertures that are compensated in two dimensions, according to the present disclosure. Mask 1000 is similar to mask 702, except that mask 1000 includes a film 1002 and apertures 1004, which are arranged in a two-dimensional pattern 1006 configured to deposit material 116 onto a two-dimensional pattern of sub-pixel locations 202 with a uniform center-to-center spacing of s1 along the x-direction and s2 along the y-direction. Aperture pattern 1006 includes an arrangement of apertures 1004(i,j) that is symmetric about a center point c, where i=-m to +m and j=-n to +n.

[0060] For clarity, the apertures 1004 are drawn relative to their corresponding sub-pixel locations 1008. As can be seen from FIG. 10 , the apertures are shifted inward (i.e., toward the center of the mask) by increasing amounts in both the x and y dimensions relative to their corresponding sub-pixel locations according to their distance from the center point cp to achieve the compensation discussed above. Along the x direction, the center-to-center distance between adjacent apertures 1004(i,j) and 1004(i+1,j) is designated s1(i). In a similar manner, along the y direction, the center-to-center distance between adjacent apertures 1004(i,j) and 1004(i,j+1) is designated s2(j).

[0061] It should be noted that it is difficult, if not impossible, to adequately characterize the actual shift for a typical microdisplay. For example, a WUXGA format microdisplay has a resolution of 1200x1920 pixels and a pixel density of 2645 PPI (pixels per inch). Each subpixel has a shortest dimension of 2.45 microns. There are over 2 million subpixels for each microdisplay, and the number of such WUXGA microdisplays on a 200 mm diameter wafer, for example, is close to 70. Rigorous calculations must be performed to calculate the required shift for each aperture relative to its corresponding pixel position at a fixed mask-to-wafer gap value.

[0062] It should be understood that the present disclosure teaches only some embodiments according to the present disclosure, that many variations will be readily apparent to those skilled in the art after reading the present disclosure, and that the scope of the present invention is determined by the claims that follow. [Explanation of symbols]

[0063] 100 systems 102 Source 104 Shadow Mask 106 Mask chuck 108 Substrate chuck 110 Substrate 112 Material Pattern 114 Opening Pattern 116 Material 118 Vapor plume, substrate 200 configuration 202 subpixel positions 204 Aperture 302 areas 400 configuration 402 Shadow Area 404 Feather Region 700 System 702 Shadow Mask 704 opening pattern 706 Material Pattern 800 configuration 802 Aperture 900 configuration 1000 masks 1002 Membrane 1004 Aperture 1006 2D pattern, opening pattern, 2D opening pattern 1008 subpixel positions

Claims

1. A system for directly depositing material onto a substrate including a plurality of subpixel positions arranged along a first dimension and a second dimension, A source for providing evaporated material, A shadow mask having a plurality of openings arranged in a two-dimensional pattern, wherein the plurality of openings correspond one-to-one to a plurality of subpixel positions, each pair of adjacent openings among the plurality of openings has a first spacing based on the positions of an adjacent pair of openings along a first dimension, and each pair of adjacent openings among the plurality of openings has a second spacing based on the positions of an adjacent pair of openings along a second dimension, A substrate chuck for holding the substrate, Equipped with, The shadow mask is positioned between the source and the substrate when the substrate is held in the substrate chuck.

2. The system according to claim 1, wherein the plurality of subpixel positions have a uniform intercenter distance along the center point and the first dimension, and when the shadow mask and the substrate are aligned, the plurality of apertures are concentric with the plurality of subpixel positions, and further, the first spacing depends on the positions of adjacent pairs of apertures among the plurality of apertures with respect to the center point.

3. The system according to claim 2, wherein the second interval further depends on the size of the gap between the shadow mask and the substrate and the size of the input distance between the source and the substrate.

4. The system according to claim 2, wherein the first interval decreases monotonically with respect to the distance from the center point along the first dimension.

5. The system according to claim 1, wherein the plurality of subpixel positions have a center point, a uniform intercenter distance along the first dimension, and a uniform intercenter distance along the second dimension, and when the shadow mask and the substrate are aligned, the plurality of apertures are concentric with the plurality of subpixel positions, and further, the first spacing depends on the positions of adjacent pairs of apertures among the plurality of apertures along the first dimension with respect to the center point, and the second spacing depends on the positions of adjacent pairs of apertures among the plurality of apertures along the second dimension with respect to the center point.

6. The system according to claim 5, wherein the first interval decreases monotonically with respect to the distance from the center point along the first dimension, and the second interval decreases monotonically with respect to the distance from the center point along the second dimension.

7. A method for directly depositing a first material onto a substrate including a plurality of subpixel positions arranged along a first dimension and a second dimension, A step of placing a shadow mask between a source for vaporizing the first material and the substrate, wherein the shadow mask includes a plurality of openings arranged in a two-dimensional pattern, the plurality of openings corresponding one-to-one to a plurality of subpixel positions, each pair of adjacent openings among the plurality of openings having a first spacing based on the positions of an adjacent pair of openings along a first dimension, and each pair of adjacent openings among the plurality of openings having a second spacing based on the positions of an adjacent pair of openings along a second dimension. The first step of vaporizing the aforementioned first material, The steps include passing the vaporized first material through the shadow mask onto a plurality of the subpixel positions, and Methods that include...

8. The method according to claim 7, further comprising the step of providing the shadow mask such that the plurality of subpixel positions have a uniform intercenter distance along the center point and the first dimension, and when the shadow mask and the substrate are aligned, the plurality of openings are concentric with the plurality of subpixel positions, and the first spacing depends on the positions of adjacent pairs of the plurality of openings with respect to the center point.

9. The method according to claim 8, wherein the shadow mask is provided such that the second interval further depends on the size of the gap between the shadow mask and the substrate and the size of the input distance between the source and the substrate.

10. The method according to claim 8, wherein the shadow mask is provided such that the first interval decreases monotonically with respect to the distance from the center point along the first dimension.

11. The method according to claim 7, wherein the shadow mask is provided such that the plurality of subpixel positions have a center point, a uniform intercenter distance along the first dimension, and a uniform intercenter distance along the second dimension, and when the shadow mask and the substrate are aligned, the plurality of openings are concentric with the plurality of subpixel positions, and further, the first spacing depends on the positions of adjacent pairs of openings among the plurality of openings along the first dimension with respect to the center point, and the second spacing depends on the positions of each of adjacent pairs of openings among the plurality of openings along the second dimension with respect to the center point.

12. The method according to claim 11, wherein the shadow mask is provided such that the first spacing decreases monotonically with the distance from the center point along the first dimension, and the second spacing decreases monotonically with the distance from the center point along the second dimension.

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