Mask-free photolithographic exposure using a matrix-addressable micropixellated AlInGaN ultraviolet light-emitting diode

Jeon, Chan‐Wook; Gu, Erdan; Dawson, Martin D.

doi:10.1063/1.1942636

Cited by 53 publications

(28 citation statements)

References 12 publications

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“…The functionality of UV emitters is further enhanced by introducing individuallyaddressable emissive elements on a micrometer-scale. Such micro-LED arrays have been demonstrated for microdisplay purposes, but are being developed as an exposure tool for photolithography [2]. Avoiding costly photomasks and mask aligner in traditional lithography system, direct-write ultraviolet micro-LED arrays could offer an alternative technique to traditional photolithography.…”

Section: Introductionmentioning

confidence: 99%

An ultraviolet micro‐LED array and its application for microlens fabrication

Luan

Lai

Choi

2010

Phys. Status Solidi (c)

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We report on a direct‐write lithographic technique for the fabrication of micro‐lens arrays with an ultraviolet (UV) micro‐light‐emitting diode (LED) array, serving as an exposure source. Owing to the Lambertian emission distribution of LEDs, the exposed UV sensitive coating (UV epoxy) adopts the same profile, resulting in spherical lenses being formed naturally, without further reflow. This technique is distinctive from conventional UV curing method and possesses many advantages, including simplicity of processing, allows control of the dimensions of micro‐lenses through process parameters, and is readily scalable. Micro‐lens arrays of high optical quality have been fabricated by this method. The properties of the lenses are evaluated by optical microscopy and atomic force microscope. The determined focal length is close to the predicted value. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Introductionmentioning

confidence: 99%

An ultraviolet micro‐LED array and its application for microlens fabrication

Luan

Lai

Choi

2010

Phys. Status Solidi (c)

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“…Furthermore, the output power of these LEDs and their emission mode (pulsed and dc) can be easily changed via an integrated electronic driver circuit. Several proof-of-concept demonstrations of micro-patterning by LED direct writing have already been made using either conventional broad-area devices or micro-LEDs (we consider an LED as "micro" when one of its dimensions is below 100 µm) [5]- [7]. Feature sizes as small as 20 µm were obtained by using proximity exposure with micro-LEDs, while similar feature sizes have also been obtained using a broad-area LED source coupled to a microscope objective [5], [6].…”

Section: Introductionmentioning

confidence: 99%

“…Several proof-of-concept demonstrations of micro-patterning by LED direct writing have already been made using either conventional broad-area devices or micro-LEDs (we consider an LED as "micro" when one of its dimensions is below 100 µm) [5]- [7]. Feature sizes as small as 20 µm were obtained by using proximity exposure with micro-LEDs, while similar feature sizes have also been obtained using a broad-area LED source coupled to a microscope objective [5], [6]. The use of micro-LEDs brings the primary advantages of offering a large density of emitters on a small-scale chip, and a higher power density per pixel than broad-area LEDs [8].…”

Section: Introductionmentioning

confidence: 99%

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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“…The low cost and long lifetime of the LEDs make them an attractive alternative light source for lithography, however the small beam size and low power (<2 mW) makes it impractical to expose a large area through a mask as in 4 The new technique presented here is a rapid prototyping technique, avoiding the investments required for laser ablation or for the fabrication of high resolution moulds by non-lithographic approaches like micro electrode discharge machining (l-EDM) and milling. 5, 6 Other simple and rapid fabrication methods including the use of a photocopier, 7 toner mediated lithography, 8 or etching through a mask made using a cutter plotter 9 are limited to the fabrication of channels that are more than 200 lm wide.…”

Section: Introductionmentioning

confidence: 99%

Maskless photolithography using UV LEDs

Guijt¹,

Breadmore²

2008

Lab Chip

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A UV light emitting diode (LED) with a maximum output of 372 nm was collimated using a pinhole and a small plastic tube and focused using a microscope objective onto a substrate for direct lithographic patterning of the photoresist. Movement of the substrate with a motorised linear stage (syringe pump) allowed lines in SU-8 to be pattered with a width down to 35 lm at a linear velocity of 80 lm s −1 , while in the dry film resist Ordyl SY 330, features as narrow as 17 lm were made at a linear velocity of 245 lm s −1 . At this linear velocity, a 75 mm long feature could be patterned in 5 min. Functional microfluidic devices were made by casting PDMS on a master made by LED lithography. The results show that UV LEDs are a suitable light source for direct writing lithography, offering a budget friendly, and high resolution alternative for rapid prototyping of features smaller than 20 lm.

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Mask-free photolithographic exposure using a matrix-addressable micropixellated AlInGaN ultraviolet light-emitting diode

Cited by 53 publications

References 12 publications

An ultraviolet micro‐LED array and its application for microlens fabrication

An ultraviolet micro‐LED array and its application for microlens fabrication

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

Maskless photolithography using UV LEDs

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