Sample Devices for NAIL Thermal Imaging and Nanowire Projects

Sample Devices for NAIL Thermal Imaging and

Nanowire ProjectsDesign and Fabrication

Mead MišićSelim Ünlü

Boston University

Outline

The NAIL and Nanowire Projects NAIL Microscopy and Applications Nanowire Research Objectives Sample Requirements

Sample Design and Mask Fabrication Process of Sample Device

Manufacturing Conclusion Questions

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Problem with the imaging of the Si ICs

Metal layer on top of the ICs often make imaging from the substrate an easier option

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Conventional Optical Microscopy Refraction reduces

sinθa by a factor of n, so maximum θa=θc

Total internal reflection θc = sin-1 (1/n)

Resolution Diminished

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NAIL Microscopy

Using a silicon lens as a coupler

Maximum θa = π/2 Reflection loss at

interfaces is minimized.

Evanescent wave coupling between the NAIL and substrate

Resolution Improved

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NAIL Thermal Imaging TestsImaging test with aluminum wires

Without NAIL With NAIL

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NAIL Thermal Imaging Resolution

No actual real device-like sample imaged yet

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The Nanowire Project

The goal is to research the conductivity of polymer nanowires for possible integrated sensing applications

Drawing of the previous nanowire sample

Metal Au Metal Au

Silicon Substrate

Nanowire Conductor

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Nanowire Sample Proposal

Drawing of the proposed device for high throughput measurements of the transport properties of conducting polymer nanowires.

MetalOxide

MetalOxide

n+ or p+ n+ or p+

Nanowire Conductor

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Sample Device Requirements NAIL Requirements

Emission lines ranging from 0.8um - 5.0um Width of the spaces between the emission

lines ranging from 0.8um - 5.0um To generate a sufficient amount of emission

Nanowire Project Requirements Space between implant areas varying Conducting areas to be flat (implanted)

Samples to be manufactured on silicon substrate

Samples to be manufactured using the same masks

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Design Constraints and Decisions 4 inch platform Large metal contact areas P-type pre-doped wafers All ion implants to be n-type Leakage prevention (isolation

implant or etch) Leave room for error

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The Wafer Mask Layout

The picture shows the layout of the devices in CAD using all 5 masks.

The masks were manufactured at EPFL in Switzerland.

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A Die Layout

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Basic Device Dimensions

The dimensions indicated are identical in all the devices.

3500um

1500um1600um

400um

1500

um

100u

m

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NAIL – Periodic Devices

Each Device contains 3 implant sections like the one above, with each section containing two samples

Samples consist of lines and spaces of equal thicknesses

The thicknesses are: 0.8, 1.0, 1.2, 1.5, 2.0, 5.0 um

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Boston University

NAIL – Aperiodic Devices

Each device contains 3 implant sections like the one above with each section containing 2 samples

Samples consist of lines of constant width and variable spacing.

The spacing widths are: 0.8, 1.0, 1.2, 1.5, 2.0, 5.0um

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Boston University

NAIL - Variable Width Device

Device to be used for NAIL Qualification 100um x 100um metal to implant contact Line thicknesses: 0.8,0.9,1.0,1.2,1.5,2.0,3.0 um Spacing between the lines 10um constant

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Boston University

NAIL – Parallel Devices

There are two separate Parallel Devices0.8-1.2 um parallel device1.5-3.0 um parallel device

Each device contains 3 samples, and each sample has lines of variable width and constant spacing in between

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Nanowire Devices

Similar size and dimensions as in NAIL devices Large metal contacts for easy activation Implant areas a varying space apart for

nanowire lines to be drawn

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Nanowire Devices

There are 2 different nanowire devices with 3 samples on each device.

Separation distances between the implant areas are: 1, 2, 3, 5, 10, and 20um

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Sample Device Fabrication

5 Masks manufactured, 4 being used

4 inch wafer platform 5 p-type lightly doped wafers Implants used all n-type Using BU ECE semiconductor

manufacturing lab equipment, ion implanters from Implant Sciences, and potentially other tools.

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Fabrication – Silicon Wafers

Lightly P-doped Silicon Wafers 5 Pieces One side polished

Si <100> 22 ohm*cm Boron (p-) doped wafer

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Phase 1 – Photoresist Application PR Shipley S1813 Photoresist 4000 RPM for 30 Seconds Uniform 1.5um thickness Development

Photoresist S1813, Thickness=1.5um


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Phase 1 - Mask 1 Exposure

UV Exposure using S. Microtek Expose at 8mW for 12sec

Mask 1


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Phase 1 - Etching into Silicon

Etch 700nm into Silicon Isolation Trench and Aligner Markers Easier Navigation while Processing


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Phase 1 – PR Removal and Cleaning PR Removal using Acetone,

Methanol, and DI Water Particle Removal using RIE Asher


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Phase 2 – P+_130keV Simulation

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Phase 2 - Photoresist Application PR S1813 Photoresist 5000 RPM for 60 Seconds Uniform 1.0um thickness Development



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Mask 3

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Phase 2 - P+_130keV Implant Phosphorus Ion Implant at 130keV with

1e15 ions/cm^2 and 7 degree θ angle done at Implant Sciences

P+

Si <100> 22 ohm*cm B- doped wafer

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Phase 2 - PR Removal and Cleaning PR Removal using Acetone, Methanol,

and DI Water Using HTEA recipe on Fusion Asher


P+

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Phase 2 – Ion Implant Anneal 3 minute anneal at 1050C Longer anneal expands the implanted area

and activates it fully This implant will create a pn-junction

preventing any leakage between the metal contacts.


P+

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Phase 3 – As+_30keV Simulation

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Phase 3 – Photoresist Application PR S1813 Photoresist 6000 RPM for 90 Seconds Uniform sub-1.0um thickness Development

Photoresist S1813, Thickness <1.0um


P+

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Mask 3Mask 4

P+

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Phase 3 - As+_30keV Implant Arsenic Ion Implant at 30keV with 1e15

ions/cm^2 and 7 degree θ angle done at Implant Sciences


As+P+

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Phase 3 – PR Removal and Cleaning PR Removal using Acetone,

Methanol, and DI Water Using Fusion Asher HTEA recipe


P+As+

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Phase 3 – Ion Implant Anneal

30 second anneal at 1100C Short anneal time prevents the

implanted area from expanding


P+As+

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Phase 4 – Photoresist Application PR S1813 Photoresist 4000 RPM for 30 Seconds Uniform 1.5um thickness Development



P+As+

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Mask 3Mask 5

P+As+

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Phase 4 – Aluminum SputteringAluminum deposition via evaporation

P+ As+

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Phase 4 – Aluminum Liftoff and PR Removal Al Liftoff to remove the extra aluminum PR removal using Acetone, Methanol

and DI Water

P+As+

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Conclusion

To provide samples for NAIL thermal imaging and Nanowire projects NAIL: Provide various 0.8um-5.0um features

for imaging in various configurations Nanowire: Provide samples with implanted

areas connected to large metal contacts A sufficient amount of samples Leave a foundation for simpler future

sample device manufacturing

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Questions?

Documents

Sample Devices for NAIL Thermal Imaging and Nanowire Projects