Mask-less ultraviolet photolithography based on CMOS-driven micro-pixel light emitting diodes

Elfström, David; Guilhabert, Benoit; McKendry, Jonathan J. D.; Poland, Simon P.; Gong, Zheng; Massoubre, David; Richardson, E.; Rae, Bruce R.; Valentine, G.J.; Blanco-Gomez, G.; Gu, Erdan; Cooper, Jonathan M.; Henderson, Robert K.; Dawson, Martin D.

doi:10.1364/oe.17.023522

Cited by 28 publications

(18 citation statements)

References 18 publications

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“…In the following direct writing experiments, micro-LEDs are imaged using an optical setup as in [9], using a 4X S1805 PR feature sizes (trench bottom) exposed by representative pixels of each diameter upon increased stages velocity. Inset: AFM scan profile of a S1805 trench written at 140 µm/s −1 .…”

Section: Micro-led Mask-free Lithographymentioning

confidence: 99%

“…and 40X microscope objectives for collection and projection, respectively, and demagnifying the pixels by a factor 10. The sample covered with PR is placed on an X-Y translation stage and positioned at the focus using the highresolution z-stage supporting the 40X projection microscope objective [9]. The writing process itself is entirely automated through a computer interface.…”

Section: Micro-led Mask-free Lithographymentioning

confidence: 99%

“…The velocities of the X-Y stages are controlled to deliver the appropriate exposure dose and to adjust the feature size written into the PR. Typical writing speeds range from 20 µm/s to 140 µm/s leading to average exposure doses at focus of 280 mJ/cm 2 down to 40 mJ/cm 2 for the 14 µm-diameter pixel and from 360 mJ/cm 2 to 51 mJ/cm 2 for the 24 µmdiameter [9]. Feature sizes written at different velocities by both pixels were investigated by atomic force microscopy (AFM) over an area of 5 × 5 µm 2 of the patterned region.…”

Section: Micro-led Mask-free Lithographymentioning

confidence: 99%

“…[9] but with a 10:1 demagnification) to pattern PR with features down to 500 nm-width in order to process GaN-based LED heterostructures [9], [10]. First, a single pixel was used to pattern a sacrificial PR mask for a "checkerboard-type" array with individually addressable LEDs emitting at 450 nm [11].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Sub-Micron Lithography Using InGaN Micro-LEDs: Mask-Free Fabrication of LED Arrays

Guilhabert

Massoubre

Richardson

et al. 2012

IEEE Photon. Technol. Lett.

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The fabrication of gallium-nitride (GaN)-based light-emitting diode (LED) arrays by a direct writing technique, itself using micron-sized LEDs (micro-LEDs), is reported. CMOSdriven ultraviolet GaN-based micro-LED arrays are used to pattern photoresist layers with feature sizes as small as 500 nm. Checkerboard-type square LED array devices are then fabricated using such photoresist patterns based on either single pixel or multipixel direct writing, and implemented as part of a completely mask-less process flow. These exemplar arrays are composed of either 450-nm-emitting 199 × 199 µm 2 pixels on a 200-µm pitch or 520-nm-emitting 21 × 18 µm 2 pixels on a 23-µm pitch. Fill factors of 99% and 71.5% are achieved with optical output power densities per pixel of 5 and 20 W/cm 2 at 90-and 6-mA dc-injected currents, respectively.Index Terms-Gallium nitride, micro light-emitting diodes (micro-LEDs), nanolithography, semiconductor device manufacture.

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Section: Micro-led Mask-free Lithographymentioning

confidence: 99%

Section: Micro-led Mask-free Lithographymentioning

confidence: 99%

Section: Micro-led Mask-free Lithographymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sub-Micron Lithography Using InGaN Micro-LEDs: Mask-Free Fabrication of LED Arrays

Guilhabert

Massoubre

Richardson

et al. 2012

IEEE Photon. Technol. Lett.

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“…Not surprisingly, GaN‐on‐Si‐based devices are able to compete with the GaN‐on‐sapphire counterparts in the field of optoelectronics , including detectors, sensors, and advanced light‐emitting sources. The development of micro‐LEDs comprised a dense addressable array of miniature LEDs further enable micro‐display applications ranging from general lighting to neuroscience, structured light microscopy, maskless lithography and communications . In most of the previous reports on micro‐pixelated GaN LEDs, the formation of pixels relies on the GaN‐on‐sapphire platform and typically involves etching through a photo‐lithographically defined masking layer beyond the quantum well region .…”

Section: Introductionmentioning

confidence: 99%

Optical crosstalk analysis of micro‐pixelated GaN‐based light‐emitting diodes on sapphire and Si substrates

Cheung

Tang

et al. 2016

Physica Status Solidi (a)

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With the aid of depth‐resolved confocal microscopy, the optical crosstalk phenomenon in GaN‐based micro‐pixel light‐emitting diodes (μ‐LEDs) on Si substrates are thoroughly investigated and compared with its counterpart on sapphire substrate. Noticeable optical crosstalk is invariably present in GaN‐on‐sapphire devices as the thick transparent sapphires beneath the μ‐LEDs serve as optical waveguides to favor lateral propagation of the emitted light, eventually causing unwanted noise signals. μ‐LEDs adopting the GaN‐on‐Si platform can effectively suppress unwanted optical crosstalk and sustain superior performance at different injection currents, which are well‐suited for a wide range of μ‐LED applications. Light intensity maps illustrating crosstalk performances of GaN‐on‐sapphire μ‐LEDs with backsides coated with (left) Al mirror and (middle) black paint, and (right) GaN‐on‐Si μ‐LED, captured by confocal microscopy.

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High‐Resolution 960 × 540 and 1920 × 1080 UV Micro Light‐Emitting Diode Displays with the Application of Maskless Photolithography

Chen

2021

Advanced Photonics Research

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Herein, active matrix 370 nm ultraviolet (UV) micro light‐emitting diode (micro‐LED) displays with full high‐definition resolution of 960 × 540 and 1920 × 1080 and high pixel densities of almost 2000 and 3200 pixels per inch (PPI), respectively, are reported. A novel self‐aligned process is used to fabricate the 1920 × 1080 micro‐LED array with the inverted trapezoidal‐shape mesa, which is different from the conventional vertical mesa for the 960 × 540 micro‐LED array. In addition, the single pixels with the diameters of 8 and 5 μm on the 960 × 540 and 1920 × 1080 microarrays exhibit excellent characteristics, including the low forward voltages of 3.35 and 3.29 V at the currents of 17.4 and 4.4 μA, extremely low leakage currents of 19.5 and 9.4 pA at −10 V, and high light output powers of 150 and 71 μW at 1 mA, respectively. Through flip‐chip bonding technology, the 1920 × 1080 micro‐LED display has a higher light output power of 2.6 mW than the 960 × 540 micro‐LED display of 1.8 mW at the same driving current of 100 mA and voltage of 5 V. Both the UV micro‐LED displays demonstrate the delivery of graphic images and simple pattern‐programmable maskless photolithography on resist‐coated wafers.

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Mask-less ultraviolet photolithography based on CMOS-driven micro-pixel light emitting diodes

Cited by 28 publications

References 18 publications

Sub-Micron Lithography Using InGaN Micro-LEDs: Mask-Free Fabrication of LED Arrays

Sub-Micron Lithography Using InGaN Micro-LEDs: Mask-Free Fabrication of LED Arrays

Optical crosstalk analysis of micro‐pixelated GaN‐based light‐emitting diodes on sapphire and Si substrates

High‐Resolution 960 × 540 and 1920 × 1080 UV Micro Light‐Emitting Diode Displays with the Application of Maskless Photolithography

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