Library · Materials, chemistry & fabrication
What Photolithography & Microfabrication got wrong, from 49 theses
Summary written by a model from the records below: Microfabrication and photolithography investigations frequently encounter technical failures in exposure resolution, chemical processing, substrate planarization, and operational throughput. Researchers regularly abandon or reject specialized lithographic and 3D printing methods when faced with prohibitive equipment costs, mechanical fragility, or structural damage to delicate substrates. These records come from graduate theses, 2021 to 2026, each labeled with its degree where the repository states it, and each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Plus 10 problems the authors left open, listed at the end.
Failure modes, by theses reporting them
Select a mode to jump to its records.
High cleanroom costs, slow throughput, and alignment complexity impede advanced lithography techniques
Complex lithography techniques such as electron-beam writing, microstereolithography, and projection systems were often rejected due to slow processing speeds, extreme equipment costs, and alignment hurdles. Cleanroom photolithography and multi-objective setups also suffered from poor wafer-scale yield, mask inflexibility, and tedious realignment steps without providing practical benefits.
Tried and failed
maskless photolithography of thick photoresist applied to large-area microfluidic master mold fabrication. Reason: failed to faithfully reproduce fine features across large wafers, resulting in inaccurate feature spacing and fluid leakage
Multi-Niche Human Bone Marrow On-A-Chip for Studying the Interactions of Adoptive Cell Therapies with Multiple Myeloma · Georgia Tech · PhD
Tried and failed
multi-objective sequential two-photon polymerization lithography applied to multi-scale additive micro-manufacturing. Outcome: worse than baseline. Reason: tedious realignment between objectives yielded no observable benefit over a single lower-magnification objective
Additive Manufacturing of Electrical Machines and Electronic Devices · MIT · PhD
Considered and rejected
Considered and rejected: Rejected using electron beam lithography for patterning global alignment markers due to high cost and low throughput compared to photolithography.
Two-Dimensional Steep-Slope Transistors · University at Buffalo · PhD
Considered and rejected
Considered and rejected: Rejected standard cleanroom photolithography/wet etching for scalable sleep patch manufacturing due to high cost, low yield, and radial over-etching across wafers in favor of femtosecond laser micromachining.
Study Of Soft Materials, Nano-Microfabrication, And Flexible Packaging For Developing Wearable Flexible Hybrid Electronics · Georgia Tech · PhD
Considered and rejected
Considered and rejected: Rejected PDMS dome combined with chrome-on-glass photolithography base (from 2019 baseline) due to high cost, time-consuming fabrication, and poor 3D scalability.
PROOF OF CONCEPT FOR 3-D PRINTABLE GEOMETRY OF MICROFLUIDIC BENTHIC MICROBIAL FUEL CELL DEVICE (MBMFC) WITH SELF-ASSEMBLED WIRING · Naval Postgraduate School · Master's
Considered and rejected
Considered and rejected: Rejected top-down lithographic techniques (e-beam or polymer pen lithography) for substrate patterning due to high equipment cost, poor scalability, and substrate incompatibility.
Fabrications and Applications of Protein-based Bionanocomposites · Virginia Tech · Doctorate
Considered and rejected
Considered and rejected: Microfluidic PDMS-glass chips with turbidity readout abandoned due to labor-intensive cleanroom fabrication, sealing issues, and unreliable visual turbidity.
Towards point-of-care molecular diagnostics for prenatal screening · Boston University · PhD
Considered and rejected
Considered and rejected: Rejected photolithographic clean-room MEMS fabrication due to mask inflexibility and low force generation at meso-scale.
Active origami platforms for human-robot interactions · EPFL · PhD
Considered and rejected
Considered and rejected: Microscope projection photolithography (MPP) was rejected for micropatterning coverslips due to its small exposure area (~10^4 µm^2), making large cm-scale culture areas too labor-intensive.
Single Cell Transcriptomics and Spatial Localization in Mouse Neurons · Penn · PhD
Considered and rejected
Considered and rejected: Rejected PDMS channel microfabrication with cleanroom lithography for the final multiplexed diagnostic device due to high manufacturing cost, complexity, and electrode deposition hurdles.
Engineering DNA-based electrochemical diagnostics for translational applications · MIT · PhD
Considered and rejected
Considered and rejected: Rejected two-step electron-beam lithography for large-area hybrid graphene-metal antidots due to alignment complexity, choosing single-step self-aligned photolithography with AZ5214E undercut
Advanced Nanophotonics Resonator Designs for High-Performance Surface-Enhanced Vibrational Spectroscopy Sensing Applications · University at Buffalo · PhD
Optical diffraction, proximity broadening, and improper exposure dose degrade microscale pattern resolution
Diffraction limits in optical and contact photolithography prevented the faithful replication of sub-micron and nanoscale patterns. In addition, incorrect exposure doses and proximity broadening caused pattern distortions, merging of adjacent features, and incomplete developer solubility.
Tried and failed
standard short UV exposure photolithography applied to photodegradable polymer micropatterning. Reason: insufficient photochemical degradation left polymer insoluble in aqueous developer
Single Cell Transcriptomics and Spatial Localization in Mouse Neurons · Penn · PhD
Tried and failed
contact aligner photolithography applied to sub-micron feature patterning. Reason: optical diffraction limits in contact printing prevented achieving sub-micron resolution
Simulation, Generation, and Detection of Low Emittance Electron Beams for Ultrafast Science · Cornell · PhD
Tried and failed
projection photolithography for direct metal photoreduction applied to arbitrary 2D metal micropatterning. Reason: reaction-diffusion of reactive species circularized sharp features and filled internal voids
Rapid and Affordable Nanoscale Printing via Projection of Superluminescent Light · Georgia Tech · PhD
Tried and failed
optical photolithography using positive photoresist applied to dense micron-scale line arrays. Reason: optical cross-talk and proximity effect broadening degraded resolution of densely spaced features
Continuous Antibody Titer Assessment of the Biomanufacturing Process using Nanofluidic Binding Assays · MIT · PhD
Tried and failed
low-dose electron-beam lithography applied to sub-micron optical waveguide couplers. Reason: underexposure caused distorted fine features, rough edges, and severe coupling transmission losses
Concentric Microresonators Design For Dispersion Engineering and Scalable Electron-Beam Lithography for Si and SiN Photonic Platforms · Texas Tech · PhD
Tried and failed
thick single-layer photoresist lithography applied to submicron channel patterning. Reason: narrow dose window led to underdevelopment at low exposure and feature rounding at high exposure
DECIPHERING BACTERIAL CELL ENVELOPE MECHANICS AND MECHANOSENSING: A MECHANICAL ENGINEERING APPROACH · Cornell · PhD
Tried and failed
dielectric nanopillar metasurface fabrication applied to optical linear polarizers. Reason: Feature oversizing during lithography caused adjacent nanopillars to merge, introducing unwanted optical phase retardance.
Metasurface-enhanced Multispectral and Polarization Filtering for SPAD imaging sensors · EPFL · PhD
Tried and failed
Hole-based photonic crystal polarization reflectors applied to optical state transfer fidelity. Reason: Extreme fabrication intolerance where nanometer-scale feature deviations cause severe fidelity loss
Techniques for Deployed Quantum Networks with Solid-State Defect Centers · MIT · PhD
Considered and rejected
Considered and rejected: Standard photolithography for contact patterning was rejected due to 2 μm resolution limit and unique flake geometries.
Transient Investigations of High-Field Conduction in Low-Dimensional Materials · University at Buffalo · PhD
Considered and rejected
Considered and rejected: Rejected traditional optical interference lithography for fine gratings below 300 nm due to wavelength diffraction limits, switching to E-beam lithography.
Techniques for Reducing Beam-Induced Damage in Electron Microscopy · MIT · PhD
Resin entrapment, peel forces, and cytotoxic leaching hinder stereolithographic 3D printing of microfeatures
Stereolithography frequently failed at microscale dimensions because unpolymerized liquid resin remained trapped inside negative features and separation peel forces tore fragile layers. Resins and photoinitiators also raised cytotoxicity concerns and leaching issues, while slow printing speeds and poor resolution limited mold utility.
Tried and failed
stereolithography 3D printing of negative microcavity features applied to micropatterned mold fabrication. Reason: uncured liquid resin remained trapped and clogged within microscale negative hole features during printing
Programming Complex Alignment in Engineered Cardiac Tissue · Harvard · PhD
Tried and failed
3D-printed and milled molds for soft lithography applied to microfluidic channel fabrication. Reason: Molds produced via stereolithography, FDM, and CNC milling failed to yield functional PDMS channels
Investigating the role of shear stress, von Willebrand factor, platelets and neutrophils in the initiation of venous thrombosis · Imperial · PhD
Tried and failed
stereolithography at extreme layer resolutions applied to fluidic manifolds. Reason: High resolution caused thread defects and excessive print time; low resolution lacked precision, causing leaks.
Extending human interaction capabilities with soft robotics · EPFL · PhD
Lost to a baseline
SLP negative-tone polymer printing rate is 35 times slower than commercial projection two-photon lithography (Saha et al., 2019)
Rapid and Affordable Nanoscale Printing via Projection of Superluminescent Light · Georgia Tech · PhD
Considered and rejected
Considered and rejected: Rejected stereolithography 3D printing due to restriction to photo-curable resins which limits scalability to common mass-produced substrates.
Design automation and rapid prototyping of multi-component droplet microfluidic platforms · Boston University · PhD
Tried and failed
stereolithography printing with low-modulus elastomeric resin applied to cellular lattice structures. Reason: vat adhesion peel forces during separation tore delicate low-stiffness layers apart during printing
Development and mechanical characterisation of additively manufactured lattice structures · Imperial · PhD
Considered and rejected
Considered and rejected: Rejected stereolithography (SLA) 3D printing in favor of FDM due to toxicity and leaching of unreacted photoinitiators/resins.
A Multifaceted Approach to Preserve Effective Antibiotics Utilizing Antibiotic Susceptibility Testing, Antimicrobial Coatings or Glycomimetic Adjuvants · Tübingen · PhD
Considered and rejected
Considered and rejected: Solvent-based extrusion and SLA stereolithography for PCL bioscaffolds were rejected due to altered mechanical rigidity, bridging limits, and potential cytotoxicity/crosslinker biocompatibility concerns.
Additive Manufacture of Parametrically Modulated Porous Scaffold Architectures for Medical Device Applications · University College Dublin · PhD
Substrate non-planarity, film stress, and mask burial cause coating defects and lift-off failures
Spin-coating photoresist across deep trenches or non-planar microdisks led to uneven pooling and severe loss of lithographic resolution. Thick material depositions and high film stresses further caused mask burial, film peeling, delamination during stripping, and resist bridge collapse.
Tried and failed
photolithography over deep pre-etched topographical trenches applied to heater electrode patterning on semiconductor chips. Reason: Photoresist pooled unevenly into trenches, degrading spin-coating uniformity and destroying photolithographic resolution
InGaAs/InP chip-based mid-infrared optical phased arrays for communications and sensing · UT Austin · PhD
Tried and failed
metal deposition on under-exposed negative photoresist applied to flexible thin-film electrode fabrication. Reason: sub-optimally exposed photoresist led to weak adhesion causing metal delamination during stripping
Organic electrochemical transistors for neurotechnology · Imperial · PhD
Tried and failed
deep ultraviolet lithography with negative photoresists applied to microstructure patterning. Outcome: unstable. Reason: optical incompatibility and high film stress causing poor substrate adhesion
Programmable Magnetics for Microscopic Assembly, Metamaterials, and Robots · Cornell · PhD
Considered and rejected
Considered and rejected: Lift-off process using photoresist spin-coating on patterned 50 µm SU-8 microdisks was rejected due to severe non-planarity and non-uniform resist coating; stencil lithography was used instead.
Laser-Induced Forward Transfer of Functional Microdevices · EPFL · PhD
Tried and failed
nanosphere lithography lift-off patterning applied to thick multilayer thin-film deposition. Reason: deposited material thickness buried etched mask spheres, preventing solvent access and lift-off removal
The development of scalable nanostructured renewable energy devices for smart window, solar cell, and water splitting applications · UT Austin · PhD
Tried and failed
multi-scale feature etching with uniform resist mask applied to photonic crystal cavity nanofabrication. Reason: Resist thickness could not clear small features without failing to protect large features during multi-step etching.
Diamond Nanostructures with Color Centers for Quantum Technology Experiments · Harvard · PhD
Tried and failed
low-voltage electron-beam lithography for high-aspect-ratio nanogaps applied to coupled nanophotonic waveguides. Outcome: unstable. Reason: resist bridges collapsed during development due to high aspect ratio and low beam energy
Enhanced infrared sensing with plasmonic metasurfaces and undetected light · Imperial · PhD
Chemical solvents and resist processing induce degradation, contamination, and cracking in delicate polymers and 2D materials
Standard photoresists and stripping solvents like acetone and PGMEA chemically attacked and cracked polymer substrates and ferroelectric films. Lithographic chemical processing also caused oxidation of sensitive two-dimensional flakes and left unwanted polymer residues that contaminated transducer surfaces.
Tried and failed
SEBS elastomeric substrate photolithography applied to sub-micron multilayer stretchable microelectronics. Reason: SEBS elastomer is incompatible with sub-micrometer multilayer photolithography processing
Bioelectronics for Cellular Electrophysiology during Tissue Development · Harvard · PhD
Tried and failed
standard electron-beam lithography with polymer resists applied to air-sensitive thin 2D material flakes. Outcome: unstable. Reason: causes chemical degradation and oxidation of thin flakes even when using dry solvents
Probing Quantum Geometric Phenomena in Antiferromagnetic Topological Insulators · Harvard · PhD
Considered and rejected
Considered and rejected: Rejected photolithography and e-beam lithography for semiconductor patterning due to solvent/chemical degradation and steep edge angles increasing contact resistance.
Analysis of the Contact Resistance of Organic Thin-Film Transistors · EPFL · PhD
Considered and rejected
Considered and rejected: Rejected conventional photolithography with PMMA photoresist in favor of shadow masking to prevent polymer residue contamination and p-type doping on 2D transducers.
Wide- and zero-bandgap nanodevices for extreme biosensing applications · Boston University · PhD
Considered and rejected
Considered and rejected: Rejected lift-off photolithography for patterning top gold electrodes on ferroelectric polymers because standard photoresist solvents (e.g., acetone) damage the polymer structure.
Ferroelectric and energy storage characterization of PVDF-based thin films and nanocomposites · TU Wien · PhD
Considered and rejected
Considered and rejected: Rejected photolithography lift-off on top of polymer thin films because resist solvent (PGMEA) and stripping solvents (acetone) chemically attack and crack the polymer.
Ferroelectric polymer thin films for MEMS applications : towards soft and high-speed AFM probes · TU Wien · PhD
Crosslinking deficiencies and thermal instability cause mechanical failure and material leaching in photopolymerized scaffolds
Scaffolds fabricated with low initiator or precursor concentrations suffered from insufficient crosslinking and were too mechanically fragile to withstand handling or fluid flow. Thermal leaching methods failed when sacrificial microgels did not dissolve at physiological temperatures, and unwashed matrices leached unreacted material into surrounding solution.
Tried and failed
fluid evacuation combined with bulk photopolymerization applied to granular hydrogel scaffold fabrication. Outcome: unstable. Reason: polymerized scaffold ruptured mechanically upon re-exposure to fluid flow
Tried and failed
sacrificial microgel leaching for porous scaffold fabrication applied to photocrosslinkable hydrogel scaffolds. Reason: Sacrificial microgel beads failed to thermally dissolve at physiological temperature after photo-crosslinking.
Bioengineered scaffolds as a tool to decode the complexity of cancer cell interactions in vivo · Imperial · PhD
Tried and failed
photopolymerization with low precursor or initiator concentration applied to hydrogel fabrication. Reason: insufficient crosslinking led to hydrogels that were too mechanically weak to handle
POLYMERIZATION AND VOLUMETRIC PRINTING OF SOFT COMPOSITES · Cornell · PhD
Tried and failed
thermally induced phase separation scaffold fabrication applied to porous polyurethane tissue engineering scaffolds. Reason: phase separation caused macro-hole formation during freezing, impairing uniform cell seeding and adhesion
Towards personalised medicine - developing a 3D leukaemia biomimicry · Imperial · PhD
Tried and failed
drop-casting unwashed polyurethane polymer matrices applied to photocatalytic membrane fabrication. Outcome: unstable. Reason: unwashed pristine polymer matrices leach unreacted material into aqueous solution during irradiation cycles
Light-activated materials for singlet oxygen generation and the degradation of pollutants · University of Nevada, Reno · Master's
Physical machining and direct-write patterning generate surface roughness, microscale shorting, and structural artifacts
Laser direct-write and etching processes produced surface contamination, poor yields, and patterned shell artifacts compared to electron-beam tools. Mechanical milling and lithographic patterning defects also created surface roughness altering fluid shear stress and caused electrical shorting between closely spaced microgap electrodes.
Lost to a baseline
Visible meta-optics fabricated with laser direct-write (HiRes) exhibited lower resolution and patterned shell-like artifacts compared to electron beam lithography (JEOL JBX6300FS).
MEMS-integrated Alvarez Metalenses and Large-area Meta-optics · University of Washington · PhD
Considered and rejected
Considered and rejected: Rejected CNC milling of acrylic for microfluidic chip negative moulds due to ~0.1 µm surface roughness altering wall shear stress; switched to photolithography.
Platelet-inspired microparticles for targeted drug delivery to the atherosclerotic plaque · Imperial · PhD
Lost to a baseline
The 0.5 mm interference-lithography (IL) patterned scintillator exhibited worse spatial resolution (σ = 0.993 ± 0.029 mm) than the flat bare scintillator surface (σ = 0.396 ± 0.004 mm) due to nanofabrication disorder
Photonic Control of Incoherent Emission In and Out of Equilibrium · MIT · PhD
Tried and failed
Non-faradaic impedance spectroscopy on microgap interdigitated electrodes applied to bacterial cell detection. Outcome: unstable. Reason: High microfabrication shorting defects and unrepeatable impedance spectra at small interelectrode spacings
The impact of mass transport and surface charging on the performance of field effect transistor biosensors · Georgia Tech · PhD
Left open by the authors
Problems the authors named and did not get to.
Left open
Increase 3D printing resolution to fabricate thinner microfluidic channels and denser micropillar arrays for improved processing throughput. Blocker: Requires a physical wet lab, specialized high-resolution 3D printing hardware, and microfabrication materials.
Negative Enrichment of Circulating Tumor Cells Via 3D Printed Microfluidic Device · Georgia Tech · PhD
Left open
Investigate faster and cheaper deposition alternatives to ALD or alternative dielectrics like SiO2 for photonic crystal cavity filling. Blocker: Requires cleanroom fabrication facilities, wet lab chemistry, and thin-film deposition equipment.
Left open
Develop microfabricated small-scale well plates on microscope slides using two-photon polymerisation for single-FOV imaging with acoustic droplet dispensing. Blocker: Requires a physical microfabrication wet lab, two-photon polymerisation equipment, and acoustic droplet dispensers.
Parallel synthesis and screening of optical probes for G-quadruplex DNA · Imperial · PhD
Left open
Fabricate polymer interdigitated pillar electrostatic actuators scaled to micrometer dimensions using two-photon 3D printing or deep reactive-ion etching. Blocker: Requires cleanroom microfabrication equipment, two-photon 3D printers, or DRIE silicon etching apparatus
HIGH VOLTAGE PYROELECTRIC GENERATION, ELECTROSTATIC ACTUATORS, AND SENSING IN MICROSYSTEMS · Cornell · PhD
Left open
Design cost-effective integration of on-chip optical interconnects on PCBs to replace electrical traces. Blocker: Requires specialized hardware fabrication, optical engineering lab equipment, and physical prototyping facilities.
Physical Layer Data Integrity Attacks and Defenses in Cyber-Physical Systems · Virginia Tech · Doctorate
Left open
Replicate perovskite solar cell fabrication at larger scale using scalable techniques like inkjet printing, doctor blade printing, or slot-die coating. Blocker: Requires a wet-lab setup and physical deposition equipment (e.g., slot-die coater, inkjet printer).
Efficient planar formamidinium-based perovskite solar cells · Imperial · PhD
Left open
Develop glaucoma microshunt prototypes using alternative non-biodegradable gelatin copolymer materials and fabrication methods. Blocker: Requires a wet lab and specialized microfabrication equipment (e.g., projection micro-stereolithography) for polymer synthesis and prototype fabrication
A Novel Squid Glaucoma microShunt for Controlled Release of Aqueous Humor · UT Southwestern · Doctorate
Left open
Fabricate complex 3D microstructures using direct-write printing across alternative material systems beyond simple glasses. Blocker: Requires a physical high-temperature direct-write microfabrication apparatus and material synthesis lab.
MOLTEN-BASED 3-D DIRECTWRITE FABRICATION OF MICRO STRUCTURES · Georgia Tech · PhD
Left open
Design and fabricate nanoscale 3D-printed filters with parametric pores via two-photon lithography to maximize pathogen-SERS nanostructure apposition. Blocker: Requires advanced physical fabrication hardware (two-photon lithography system) and specialized materials/lab facilities.
Raman spectroscopy for point of care urinary tract infection diagnosis · Imperial · PhD
Left open
Optimize electrode geometry, impedance frequency, and polyaniline layer thickness for the printed root-monitoring sensors. Blocker: Requires wet lab fabrication facilities for screen printing and electrochemical sensor testing
Plant-on-a-chip: monitoring chemical responses in living plants with printed sensors · Imperial · PhD
Who has worked on this
Authors of the public theses cited on this page, most-cited first.
- Jungho Choi · Georgia Tech · PhD · 2026
Rapid and Affordable Nanoscale Printing via Projection of Superluminescent Light - Jihoon Kim · Penn · PhD · 2024
Single Cell Transcriptomics and Spatial Localization in Mouse Neurons - Yufei Liu · Harvard · PhD · 2026
Probing Quantum Geometric Phenomena in Antiferromagnetic Topological Insulators - Joshua Sebeal Dupaty · Boston University · PhD · 2026
Towards point-of-care molecular diagnostics for prenatal screening - Mehedi Hasan · Texas Tech · PhD · 2026
Concentric Microresonators Design For Dispersion Engineering and Scalable Electron-Beam Lithography for Si and SiN Photonic Platforms - Yangshuo Hu · Imperial · PhD · 2025
Platelet-inspired microparticles for targeted drug delivery to the atherosclerotic plaque - Xingcheng Zhou · MIT · PhD · 2025
Engineering DNA-based electrochemical diagnostics for translational applications - Simo Pajovic · MIT · PhD · 2025
Photonic Control of Incoherent Emission In and Out of Equilibrium - Toby Severs Millard · Imperial · PhD · 2025
Enhanced infrared sensing with plasmonic metasurfaces and undetected light - Jorge Cañada Pérez-Sala · MIT · PhD · 2025
Additive Manufacturing of Electrical Machines and Electronic Devices - Chufan Zhou · EPFL · PhD · 2025
Metasurface-enhanced Multispectral and Polarization Filtering for SPAD imaging sensors - Davide Disnan · TU Wien · PhD · 2025
Ferroelectric and energy storage characterization of PVDF-based thin films and nanocomposites
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