CN109642313B - High-precision shadow mask deposition system and method - Google Patents

Abstract

A direct deposition system capable of forming high resolution material patterns on a substrate is disclosed. Vaporized atoms from an evaporation source are passed through a pattern of apertures of a shadow mask to deposit on the substrate in a desired pattern. Before reaching the shadow mask, the vaporized atoms pass through a collimator that operates as a spatial filter that blocks any atoms that do not travel in a direction nearly perpendicular to the substrate surface. Thus, the vaporized atoms passing through the shadow mask exhibit little or no lateral spreading (i.e., feathering) after passing through their apertures, and the material is deposited on the substrate in a pattern with very high fidelity to the aperture pattern of the shadow mask. Accordingly, the present invention alleviates the need for relatively large spaces between regions of deposited material, as is typically required in the prior art, thereby enabling high resolution patterning.

Description

High-precision shadow mask deposition system and method

Statement of related cases

Priority is claimed for united states provisional patent application serial No. 62/340,793 (attorney docket No. 6494-208PR1), filed on 24/5/2016, which is incorporated herein by reference.

Technical Field

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

Background

Shadow mask based deposition is a process of depositing material onto the surface of a substrate such that the deposited material is patterned as desired during the deposition process itself. This is commonly referred to as a patterned layer of "directly patterned" material.

In a typical shadow mask deposition process, the desired material is vaporized at a source some distance from the substrate. As the vaporized atoms of the material travel toward the substrate, they must pass through a shadow mask positioned directly in front of the substrate surface. The shadow mask contains openings (i.e., apertures) that are arranged to match the arrangement of the desired pattern of material on the substrate (in a manner similar to a screen or artistic stencil). Thus, the vaporized atoms are deposited on the substrate surface only through the pores.

Shadow mask based deposition has been used in the Integrated Circuit (IC) industry for many years to deposit patterns of material on substrates, due in part to the fact that it avoids the need to pattern a layer of material after it is deposited. Thus, their use does not require exposing the deposited material to harmful chemicals (e.g., acidic etchants, caustic lithographic development chemicals, and the like) to pattern them. In addition, their use also reduces the handling and additional throughput that the substrate must undergo, thereby reducing substrate damage and increasing manufacturing yield. For many materials, such as organic materials, patterning through a shadow mask is actually essential because the material cannot withstand the lithography chemistry.

Unfortunately, the feature resolution that can be obtained by shadow mask deposition can be reduced by the fact that the deposited material tends to spread laterally after passing through the shadow mask, known as "feathering". Thus, the critical features must be separated by a relatively large open space area between them. In many applications, this has limited the density of overall device resolution that can be achieved.

For example, Active Matrix Organic Light Emitting Diode (AMOLED) displays require deposition of their light emitting materials based on a shadow mask, since these materials cannot withstand photolithography or etching. For full-color AMOLED displays, each display pixel includes several regions, called "subpixels," that each emit a different color. However, due to feathering issues, a relatively large safety margin gap must be included between these sub-pixel regions to ensure no overlap in the deposited material. In some cases, these gaps must be almost as large as the subpixels themselves, which introduces undesirable optical artifacts, especially when viewed in near-eye applications (e.g., head-mounted displays). Thus, prior art AMOLED displays have typically been limited to about 600 pixels per inch (ppi) or less, which is insufficient for many applications including near-eye augmented reality and virtual reality applications. In addition, the need for large gaps between sub-pixels results in a reduced pixel fill factor, which reduces display brightness. Therefore, the current density through the organic layers must be increased to provide the desired brightness, which shortens the display lifetime.

An alternative approach is to use a shadow mask with apertures as large as the active area of the display itself to deposit the emissive monochromatic white-light organic layer across the entire display and then pattern or deposit the red, green and blue filters on top of the OLED. These color filters absorb all of the emitted white light except for the red, green, or blue portions of the spectrum (depending on the color filter) to allow a full color image to be produced. However, these color filters absorb up to 80% of the emitted light, which significantly reduces the display brightness, again requiring operation at higher than desired drive currents.

There remains an unmet need in the art for a process suitable for directly patterning a high resolution material pattern on a substrate.

Disclosure of Invention

The present invention enables high resolution direct deposition of a patterned material layer on a substrate. Embodiments of the present invention filter the propagation angle of vaporized atoms to a narrow range around the direction normal to the surface of the substrate. Thus, feathering of the deposited material outside the lateral dimensions of the features of the shadow mask is mitigated. Embodiments of the present invention are particularly suitable for depositing sensitive materials such as organic light emitting materials. Embodiments are also well suited to depositing other thin and thick film layers in packaging applications, integrated circuit processing applications, and the like.

An illustrative embodiment of the present invention is a direct patterning deposition system in which material is vaporized at a source such that it is deposited on a surface of a substrate after passing through a pattern of apertures of a shadow mask. The vaporized atoms pass through a collimator that blocks all vaporized atoms except those having a propagation angle close to a direction perpendicular to the surface of the substrate before they reach the shadow mask. Thus, the lateral deviation between the aperture and its corresponding deposited material region is reduced compared to the prior art.

The collimator includes a plurality of channels having high aspect ratios, wherein longitudinal axes of the channels are substantially aligned with a vertical direction. Therefore, vaporized atoms that do not travel in a direction close to vertical are blocked by the inner side walls of the channel.

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

In some embodiments, the source is a linear source emitting a fan-shaped steam plume, wherein the linear source moves in a direction that is not aligned with its longitudinal axis. In some of these embodiments, the source is moved in a direction substantially orthogonal to both the longitudinal axis and the vertical direction of the source. In several of these embodiments, the source is moved along a non-linear path.

In some embodiments, the source includes a plurality of individual nozzles, each of which emits a conical vapor plume such that the nozzles collectively provide a substantially uniform flow of vaporized atoms over the area of the substrate surface.

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

An embodiment of the invention is a system for depositing a first material on a plurality of deposition sites in a deposition area of a substrate, the plurality of deposition sites being arranged in a first arrangement, wherein the system comprises: a source for providing a first plurality of vaporized atoms of the first material, each of the first plurality of vaporized atoms propagating along a propagation direction characterized by a propagation angle relative to a first direction perpendicular to a first plane defined by the substrate, wherein a range of propagation angles for the first plurality of vaporized atoms spans a first angular range; a shadow mask comprising a plurality of apertures arranged in the first arrangement; and a collimator comprising a plurality of channels, the collimator being interposed between the source and the shadow mask, wherein each of the plurality of channels is sized and arranged to pass only vaporized atoms having a propagation angle within a second angular range that is less than the first angular range.

Another embodiment of the invention is a system for depositing a first material on a plurality of deposition sites in a deposition area of a substrate, the plurality of deposition sites arranged in a first arrangement, wherein the system comprises: a source operable to provide a plurality of vaporized atoms, each of the plurality of vaporized atoms traveling along a propagation direction defining a propagation angle, wherein the plurality of propagation angles span a first angular range; a shadow mask comprising a plurality of apertures arranged in the first arrangement, wherein the shadow mask and the plurality of deposition sites together define an acceptable angular range that is less than the first angular range; and a collimator positioned between the source and the shadow mask, the collimator comprising a plurality of channels, each of the plurality of channels having a high-aspect ratio defining a range of filter angles less than or equal to the range of acceptable angles.

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, wherein the method comprises: receiving a first plurality of vaporized atoms at a collimator positioned between a source and a shadow mask having a plurality of apertures arranged in the first arrangement, wherein the first plurality of vaporized atoms is characterized by a first range of propagation angles; selectively passing a second plurality of vaporized atoms through the collimator to the shadow mask, wherein the second plurality of vaporized atoms is characterized by a second range of propagation angles that is narrower than the first range of propagation angles; and enabling at least some of the second plurality of vaporized atoms to be deposited on the substrate through the plurality of apertures.

Drawings

Fig. 1 depicts a schematic diagram of a cross-section of the main features of a direct patterning deposition system according to the prior art.

Fig. 2 depicts a schematic diagram of a cross-section of the main features of a high precision direct patterning deposition system, according to an illustrative embodiment of the invention.

Fig. 3 depicts operations of a method for depositing a layer of directly patterned material on a substrate, according to an illustrative embodiment.

Fig. 4 depicts a schematic diagram of an enlarged view of the pixel area of the substrate 102 and its corresponding aperture 120 of the shadow mask 106.

Fig. 5A depicts a schematic diagram of a cross-sectional view of a collimator in accordance with an illustrative embodiment.

Fig. 5B-C depict schematic diagrams of top and cross-sectional views, respectively, of a region of the collimator 208.

Detailed Description

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

The substrate 102 is a glass substrate suitable for forming an Active Matrix Organic Light Emitting Diode (AMOLED) display. The substrate 102 includes a surface 114 that defines a plane 108 and a vertical axis 110. Vertical axis 110 is orthogonal to plane 108. Surface 114 includes a plurality of deposition sites G for receiving green-emitting material, a plurality of deposition sites B for receiving blue-emitting material, and a plurality of deposition sites R for receiving red-emitting material. The deposition sites are arranged in a plurality of pixel regions 112 such that each pixel region includes a deposition site for a light emitting material of each color.

The source 104 is a crucible for vaporizing the material 116, which is centered with respect to the substrate 102, and the material 116 is a red-emitting organic light emitting material. As the material 116 melts or sublimates within the low pressure atmosphere of the vacuum chamber, the source 104 emits vaporized atoms 122, which vaporized atoms 122 propagate outward from the source in a ballistic manner generally toward the substrate 102. The vaporized atoms emitted by the source 104 collectively define a vapor plume 124.

Shadow mask 106 is a sheet of structural material containing apertures 120. The shadow mask is substantially planar and defines a plane 118. A shadow mask is positioned between the source 104 and the substrate 102 such that it blocks all vaporized atoms except those passing through its apertures. The shadow mask is spaced from the substrate by a spacing s (typically tens or hundreds of microns), the planes 108 and 118 are substantially parallel, and the apertures 120 are aligned with the deposition sites R.

Ideally, when the red-emitting material 116 is deposited, the vaporized atoms are only incident on the deposition site R. Unfortunately, the steam plume 124 contains vaporized atoms traveling in many different propagation directions 126, many of which are not aligned with the direction of the vertical axis 110. Thus, most of the vaporized atoms passing through the aperture 120 travel in a direction of propagation with a substantial lateral component. The point of incidence of each vaporized atom on surface 114 is geometrically dependent on its angle of propagation and the spatial relationship between the substrate and shadow mask, specifically the spacing s and alignment of apertures 120 with deposition sites R. For purposes of this specification, including the appended claims, the term "propagation angle" is defined as the angle formed by the direction of propagation of vaporized atoms relative to a direction perpendicular to the plane 108 of the substrate 102 (i.e., the vertical direction 128, which is aligned with the vertical axis 110). For example, vaporized atoms 122 travel along a propagation direction 126, the propagation direction 126 forming a propagation angle θ p with respect to a vertical direction 128.

The propagation angle of the vaporized atoms of the vapor plume 124 spans a relatively large angular range of- θ m to + θ m, which leads to significant drawbacks of prior art direct deposition systems. In particular, it results in the deposition of material 118 on surface 114 outside the perimeter of aperture 120, which is commonly referred to as "feathering". In addition, the amount of feathering at the aperture increases with the distance of the aperture from the center of the substrate 102.

Vaporized atoms 122 that reach shadow mask 106 have a propagation angle within a relatively small angular range for apertures located near the center of the vapor plume 124. In other words, it travels in a direction that is only slightly offset from the vertical axis 110. As a result, vaporized atoms passing through these apertures exhibit only minimal lateral drift (i.e., feathering) after passing through the shadow mask. Thus, in this region, the lateral extent of the deposition material 116 is generally nearly aligned with the edges of the aperture 120 (i.e., it is deposited primarily on the target deposition site R).

However, for apertures further away from the center of the vapor plume 124, vaporized atoms reaching the shadow mask 106 span a relatively large angular range and include propagation angles closer to | θ m |. Therefore, in these regions, the lateral distance traveled by the vaporized atoms after passing through the shadow mask is large, resulting in feathering of the deposited material well beyond the lateral extent of the apertures. This results in a lateral offset δ f between the edge of the aperture opening and the periphery of the area in which the material 116 is deposited. Thus, the deposition material extends beyond the area of the target deposition site. In some cases, this feathering can result in the deposition of material on adjacent deposition sites (i.e., deposition sites B and/or G) desired for different light emitting materials, thereby resulting in color mixing.

It should be noted that any additional misalignment between the shadow mask and the substrate exacerbates feathering, such as a degree of parallelism away from planes 108 and 118 (i.e., relative roll and/or pitch between the mask and the substrate), unevenness of the shadow mask and/or the substrate, and translational and/or rotational misalignment between the shadow mask and the substrate. Furthermore, in many prior art deposition systems (e.g., systems for depositing more than one material, etc.), the source 104 is positioned off-center relative to the substrate, which leads to even greater feathering problems.

However, aspects of the invention are: blocking vaporized atoms having a propagation angle greater than the desired propagation angle from reaching shadow mask 106 can significantly reduce feathering, thereby enabling the pattern of deposited material to have higher resolution and fidelity relative to the aperture pattern of the shadow mask.

Fig. 2 depicts a schematic diagram of a cross-section of the main features of a high precision direct patterning deposition system, according to an illustrative 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. The system 200 is operable to evaporate a desired pattern of material onto a substrate surface without the need for subsequent subtractive patterning operations such as photolithography and etching.

The system 200 is described herein with respect to depositing a pattern of light emitting material on a glass substrate as part of fabricating an AMOLED display. However, it should be apparent to those skilled in the art, after reading this specification, that the present invention can be directed to forming directly patterned layers of virtually any thin and thick film material (organic or inorganic) on any of a variety of substrates, such as semiconductor substrates (e.g., silicon carbide, germanium, and the like), ceramic substrates, metal substrates, plastic substrates, and the like. Moreover, although the illustrative embodiment is a thermal evaporation system, one of ordinary skill in the art will recognize, upon reading this specification, that the invention may be directed to virtually any material deposition process, such as e-beam evaporation, sputtering, and the like. Furthermore, although the depicted example is a deposition system suitable for single substrate planar processing, the present invention is also suitable for other manufacturing methods, such as cluster tool processing, track processing, roll-to-roll processing, and the like. Accordingly, the present invention is suitable for use in a variety of applications including, but not limited to, packaging applications, IC manufacturing, MEMS manufacturing, nanotechnology device manufacturing, Ball Grid Array (BGA) manufacturing, and the like.

The vacuum chamber 202 is a conventional pressure vessel operable to provide a low pressure atmosphere that supports evaporation of the material 116. It should be noted that vacuum chamber 202 can be a stand-alone unit, part of a cluster deposition system, or part of a track deposition system in which multiple evaporation chambers are arranged in a linear chain. In some embodiments, vacuum chamber 202 includes several evaporation source/shadow mask combinations capable of forming different patterns of different materials, such as, for example, a plurality of light emitting sub-pixels emitting different colors (e.g., red, green, and blue) of light.

Fig. 3 depicts operations of a method for depositing a layer of directly patterned material on a substrate, according to an illustrative embodiment. The method 300 is described herein with continued reference to fig. 2 and with reference to fig. 4 and 5A-C. The method 300 begins at operation 301, where the collimator 208 is installed in the collimator chuck 210.

The collimator 208 is a mechanically rigid plate comprising a plurality of channels separated by thin walls, as will be described in more detail below with respect to fig. 5A to C. The collimator 208 is sized and arranged to act as a spatial filter that selectively passes vaporized atoms that propagate in a direction nearly perpendicular to the plane 108 (i.e., vaporized atoms with very small propagation angles). Thus, the collimator 208 mitigates feathering across the entire 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 installed in mask chuck 206.

Mask chuck 206 is a mechanical clamp that positions shadow mask 106 between source 104 and substrate 102. In some embodiments, mask chuck 206 is an electrostatic chuck similar to substrate chuck 204. Typically, shadow mask 106 is supported only around the perimeter of shadow mask 106. Therefore, prior art shadow masks tend to sag under the force of gravity. This sag locally increases the center gap between the mask and the substrate and thus exacerbates feathering in this region. In some embodiments, mask chuck 206 includes a slight curvature (e.g., an upward slope) that biases the shadow mask upward to counteract shadow mask sag due to gravity. In some embodiments, fine support structures may extend across openings in the mask chuck 206 to support the mask and reduce gravitational sag.

In operation 303, substrate 102 is mounted in substrate chuck 204.

The substrate chuck 204 is a platen for holding the substrate 102 so that the substrate is very flat. Substrate chuck 204 is sized and arranged to contact substrate 102 from only one side (front or back side) to mitigate interference with depositing material on the other side of the substrate. In the depicted example, substrate chuck 204 is an electrostatic chuck that applies a voltage across a dielectric substance to electrostatically secure "clamp" substrate 102 in place. In some embodiments, substrate chuck 204 holds the substrate from both sides of the substrate via different means, such as vacuum mechanical clamps, and so forth. In some embodiments, substrate chuck 204 includes an in-situ gap sensor that operates in conjunction with positioning system 212 to control the spacing and parallelism between substrate 102 and shadow mask 106.

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

Positioning system 212 is a system for controlling the relative positions of substrate 102, source 104, shadow mask 106, and collimator 208. The positioning system includes three six-axis manipulators and an optical alignment system for controlling the alignment between the substrate 102 and the shadow mask 106. Each of the six-axis manipulators is operably connected with each of substrate chuck 204, mask chuck 206, and collimator chuck 210 to control their position along and rotation about each of the x-axis, y-axis, and z-axis. In some embodiments, the position of at least one of the mask chuck 206 and the collimator chuck 210 is not controlled by a six-axis positioner. In some embodiments, positioning system 212 also includes a rotary stage for controlling the relative rotational alignment of substrate 102 and shadow mask 106.

In operation 304, positioning system 212 positions the substrate and shadow mask such that deposition sites R in deposition area 216 are aligned with apertures 120, planes 108 and 118 are parallel, and the spacing s between the substrate and shadow mask is as close to zero (i.e., contact) as possible, preferably within a few microns (e.g., 1-5 microns). In some embodiments, s is another suitable spacing.

In operation 305, the source 104 generates a steam plume 124. As described above with respect to fig. 1, the propagation angle of the vaporized atoms of the vapor plume 124 spans a relatively large angular range of- θ m to + θ m.

As discussed above with respect to fig. 1, the lateral and rotational alignment between substrate 102 and shadow mask 106, the spacing s between substrate 102 and shadow mask 106, and the range of propagation angles θ p of vaporized atoms incident on the shadow mask determine the amount of feathering that occurs at the surface 114 of the substrate.

Fig. 4 depicts a schematic diagram of an enlarged view of the pixel area of the substrate 102 and its corresponding aperture 120 of the shadow mask 106. As shown in the figure, for high fidelity between the apertures 120 and the deposition of material on the deposition site R, the propagation angle of the vaporized atoms through the shadow mask 106 must be within an acceptable range of-theta a to + theta a. For purposes of this specification, including the appended claims, the term "acceptable angular range" is defined as the range of propagation angles desired through the shadow mask that span an angular range from-thetaa to + thetaa. Generally, the acceptable angular range is the angular range that enables the material 116 to be deposited only on the deposition site R after passing through the aperture 120. In some embodiments, the acceptable angular range includes a small guard band around the deposition sites to allow feathering of less than half of the spacing between the nearest deposition sites. Any vaporized atoms incident on the shadow mask having a propagation angle outside this range will deposit on the surface 114 beyond the lateral extent of the deposition site R.

In operation 306, the steam plume 124 is filtered by the collimator 208 to produce the steam column 214.

Fig. 5A depicts a schematic diagram of a cross-sectional view of a collimator in accordance with an illustrative embodiment. The collimator 208 includes a body 502 patterned to form a plurality of channels 504, each of the plurality of channels 504 extending through a thickness of the body 502.

The body 502 is a glass plate suitable for planar processing. In the depicted example, the body 502 has a thickness of about 25 millimeters (mm); however, any practical thickness may be used without departing from the scope of the invention. In some embodiments, body 502 comprises a different structurally rigid material adapted to withstand the temperatures associated with thermal and/or e-beam evaporation without significant deformation. Suitable materials for use in the body 502 include, but are not limited to, semiconductors (e.g., silicon carbide, etc.), ceramics (e.g., alumina, etc.), composites (e.g., carbon fiber, etc.), fiberglass, printed circuit boards, metals, polymers (e.g., Polyetheretherketone (PEEK), etc.), and the like.

The channels 504 are vias formed in the body 502 using conventional processing operations, such as metal forming, drilling, electron discharge machining, Deep Reactive Ion Etching (DRIE), and the like. In the depicted example, the channel 504 has a circular cross-section with a diameter of about 3 mm. Thus, channel 504 has a height-to-width aspect ratio of about 8: 1. Preferably, the aspect ratio is at least equal to 3: 1. Additionally, for aspect ratios in excess of 100:1, the flow of vaporized atoms through the collimator begins to decrease to undesirable levels; however, aspect ratios in excess of 100:1 are within the scope of the present invention. In some embodiments, the channels 504 have a non-circular cross-sectional shape (e.g., square, rectangular, hexagonal, octagonal, irregular, etc.).

The formation of channels 504 creates a plurality of walls 506 that reside between the channels. Preferably, to achieve high throughput, the walls 506 are as thin as possible without sacrificing the structural integrity of the body 502. In the depicted example, the walls 506 have an average thickness of about 500 microns; however, any practical thickness may be used for the wall 506.

Fig. 5B-C depict schematic diagrams of top and cross-sectional views, respectively, of a region of the collimator 208. The channels 504 are arranged in a honeycomb arrangement, with columns being periodic and adjacent columns being offset from their neighbors by half a period. In some embodiments, the channels are arranged in different arrangements, such as two-dimensional periodic, hexagonal close-packed, random, and the like.

As depicted in fig. 5C, the aspect ratio of the channel 504 defines a filtering angular range. For purposes of this specification, including the appended claims, the term "filter angular range" is defined as the range of propagation angles through the collimator 208 that span an angular range from-thetac to + thetac. Therefore, vaporized atoms with a propagation angle greater than | θ c | will be blocked by the collimator.

Those skilled in the art will recognize that the dimensions provided above for the body 502, the channel 504, and the wall 506 are for illustration only, and that other dimensions may be used without departing from the scope of the present disclosure.

In operation 307, the aperture 120 passes the vaporized atoms of the vapor column 214 such that they are deposited on the deposition site R in the 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 extent of vapor column 214, thereby improving deposition uniformity across deposition sites on substrate 102. In some embodiments, the positioning system 212 is operable to impart an oscillating motion to the collimator 208.

It should be noted that in the illustrative embodiment, the source 104 is generally a point source of the material 116 because the open area of its crucible is significantly smaller than the area of the substrate 102.

In optional operation 309, the positioning system 212 moves the source 104 relative to the substrate in the x-y plane to improve deposition uniformity.

In some embodiments, the source 104 is a linear evaporation source that includes a plurality of nozzles that emit a fan-shaped vapor plume of vaporized atoms. In some embodiments, the positioning system 212 moves the linear source in the x-y plane in a direction that is not aligned with its longitudinal axis to improve uniformity of the deposited material on the substrate 102. In some embodiments, this path is a line that is substantially orthogonal to both the linear arrangement of nozzles and the vertical axis 110. In some embodiments, the linear source is moved along a non-linear path in the x-y plane.

In some embodiments, the source 104 comprises a two-dimensional arrangement of nozzles, each nozzle emitting a conical vapor plume, such that the plurality of nozzles collectively provide a substantially uniform flow of vaporized atoms over the area of the substrate surface. In some embodiments, the positioning system 212 moves a two-dimensional arrangement of nozzles to promote deposition uniformity. In some embodiments, the two-dimensional arrangement of nozzles is rotated in a plane to promote deposition uniformity.

In some embodiments, the source 104 is a two-dimensional planar source that includes a layer of material 116 distributed across its top surface. The source is arranged such that this top surface is parallel to and faces the substrate 102. The material 116 vaporizes uniformly across a plane when heated. Exemplary Planar Evaporation sources suitable for use in embodiments of the present invention are disclosed in "OLED Fabrication by Using a Novel Planar Evaporation Technique" (int.j.of Photoenergy, vol 2014(18), pages 1 to 8 (2014)) (which is incorporated herein by reference).

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

It should be understood that the present disclosure teaches only some embodiments according to the invention, and that many variations of the invention can be easily envisioned by those skilled in the art upon reading the disclosure, and that the scope of the invention will be determined by the claims that follow.

Claims (11)

1. A system for depositing a first material on a plurality of deposition sites in a deposition area of a substrate, the plurality of deposition sites arranged in a first arrangement, wherein the system comprises:

a source for providing a first plurality of vaporized atoms of the first material, each of the first plurality of vaporized atoms propagating along a propagation direction characterized by a propagation angle relative to a first direction perpendicular to a first plane defined by the substrate, wherein the first plurality of vaporized atoms has a first range of propagation angles spanning a first range of angles;

a shadow mask comprising a plurality of apertures arranged in the first arrangement;

a mask chuck configured for supporting the shadow mask only around its perimeter, the mask chuck including an upward slope that biases the shadow mask upward to mitigate gravity-induced sagging of the shadow mask;

a fine support structure extending across an opening in the mask chuck to support the shadow mask and reduce the gravity induced sag; and

a collimator comprising a plurality of channels having a high-to-wide aspect ratio based on an acceptable angular range that enables the first material to be deposited only on the deposition site after passing through the aperture, the collimator between the source and the shadow mask, wherein the collimator is configured to selectively pass a second plurality of vaporized atoms included in the first plurality of vaporized atoms, wherein the second plurality of vaporized atoms has a second range of propagation angles that spans a second angular range, the second angular range being narrower than the first angular range; and is

Wherein the high-aspect ratio defines a filtering angular range that is less than or equal to the acceptable angular range.

2. The system of claim 1, wherein the aspect ratio is equal to or greater than 3: 1.

3. The system of claim 1, wherein the first material is an organic material.

4. The system of claim 3, wherein the first material is an organic material operable to emit light.

5. The system of claim 1, wherein the deposition region has a first length along a second direction orthogonal to the first direction, and wherein the source includes a plurality of nozzles for emitting the plurality of vaporized atoms arranged in a second arrangement having a second length along the second direction, the second length being greater than or equal to the first length.

6. The system of claim 5, wherein the source is movable relative to the deposition area along a third direction, the first, second, and third directions being mutually orthogonal.

7. The system of claim 1, further comprising a positioning system operable to impart relative motion between the substrate and the collimator.

8. The system of claim 7, wherein the source includes a two-dimensional arrangement of nozzles that emit a conical vaporized atom plume, and wherein the positioning system is operable to rotate the two-dimensional arrangement of nozzles in a plane.

9. A method for depositing a first material on a plurality of deposition sites arranged in a first arrangement on a substrate, wherein the method comprises:

providing a collimator including a plurality of channels, each channel of the plurality of channels having a high-to-wide aspect ratio based on an acceptable angular range that enables the first material to be deposited only on the deposition site after passing through a plurality of apertures, wherein the high-to-wide aspect ratio defines a filter angular range that is less than or equal to the acceptable angular range;

installing a shadow mask having the plurality of apertures arranged in the first arrangement into a mask chuck configured for supporting the shadow mask only around its perimeter and the mask chuck inducing an upward bias on the shadow mask to mitigate gravity induced sag of the shadow mask;

supporting the shadow mask with fine support structures located in openings of the mask chuck to reduce the gravity induced sag of the shadow mask;

receiving a first plurality of vaporized atoms at the collimator, wherein the first plurality of vaporized atoms is characterized by a first range of propagation angles;

selectively passing a second plurality of vaporized atoms through the collimator to the shadow mask, wherein the second plurality of vaporized atoms is characterized by a second range of propagation angles that is narrower than the first range of propagation angles, wherein the second range of propagation angles is determined by the high-aspect ratio; and

enabling at least some of the second plurality of vaporized atoms to be deposited on the substrate through the plurality of apertures.

10. The method of claim 9, further comprising:

generating the first plurality of vaporized atoms at a two-dimensional arrangement of sources comprising nozzles, each nozzle emitting a conical plume of vaporized atoms; and is

Rotating the two-dimensional arrangement of nozzles in a plane.

11. The method of claim 9, further comprising providing the mask chuck such that it includes a support structure extending across the opening in the mask chuck, wherein the support structure supports the mask chuck when the shadow mask is mounted in the mask chuck.

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