Plans and status of AAO based MCP at ANL

Seon W. Lee† and H. Hau Wang*,‡

High Energy Physics Division †, Materials Science Division *,‡

Argonne National Laboratory

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Self-ordered alumina by 2-step anodization- experimental procedures

Electropolishing is carried out HClO4/EtOH

First anodization using0.3 M sulfuric acid

Selective dissolution of the formed oxide layerChromic acid/phosphoric acid

Second anodization1~2 days

Pore widening In phosphoric acid

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Diameter of pores, pore-to-pore distance, thickness of AAO

Jpn. J. Appl. Phys. Vol. 38 (1999)Nat Materials, vol 5, Sep 2006

L/D ~ 40

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Photolithography

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www.hitequest.com/Kiss/photolithography.gif

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Photolithography on Aluminum anodic oxide (AAO) using laser (400nm) writer

Create larger pores : 2 um ~ 10 um

Surface roughness on Aluminum plate –polishing Al surface before annodization

Photoresist can infiltrate into pores – deposit thin film on AAO to close pores

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Photolithography (test results - need at least 1 week or longer to test once)

10 um pores hcp (hexagonal-closed-packed)arrays on Si wafer

Same pattern on AAO : Surface roughness on Al will cause distortion of image

Al plate with smoother surface:better image

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Mechanical polishing of aluminum plate at either Jeff’s lab or APS shop

need to draw new pattern with various pore diameters (2um –10um ) and pore-to-pore distance (mask design software : L-edit)

Need to optimize various parameters : – Thin film deposition on AAO to close pores– Type of photoresist– Laser power, exposure time

Etching - AAO – Etching solution, concentration, time

Photolithography – plans for near future

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The First Strike Problem

Funnel like entrance– by the Focused Ion Beam (FIB)

Curved pores

Nanotechnology 18 (2007) 035304

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Focused Ion Beam (FIB) Microscopy and micromachining

Milling is achieved by accelerating concentrated gallium ions to a specific site, which etches off any exposed material, leaving a very clean hole or surface

MRS Bulletin, Vol 32, May 2007

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MRS Bulletin, Vol 32, May 2007

Focused Ion Beam (FIB) Microscopy and micromachining