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TimePix / InGrid Problems and solutions. Yevgen Bilevych. Amsterdam 28.01.2013. 8’’ TimePix wafer. Surface materials: - Aluminum (aluminum oxide) - Silicon nitride - Silicon oxide. 107 single chips.
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TimePix / InGridProblems and solutions Yevgen Bilevych Amsterdam 28.01.2013
8’’ TimePix wafer Surface materials: - Aluminum (aluminum oxide) - Silicon nitride - Silicon oxide 107 single chips Thickness 725 µm
10 mm 20 mm 20 mm TimePix chip 16120 mm CHIPEDGE 48.22 mm 48.22 mm Pixel Row 255 57.7 mm 28.3 mm Pixel Row 254 Pixel Row 253 14111 mm Pixel Row 1 Pixel Row 0 55 mm 55 mm Detector Guard Ring Row 20 mm 20 mm Snake Top Row Snake Bottom Row 256 x 256 pixels CHIPEDGE Column 251 Column 252 Column 253 Column 254 Column 255 Column 0 Column 2 Column 3 Column 4 Column 1 CHIPEDGE
Main technological steps for the formation of structure TimePix / SU-8 / Al grid 1. Formation of protection layer 2. Deposition of spacer material 3. Deposition of the Grid material 4. Formation of structure “support” / grid
Wafer surface quality inspection W0058 EW5MWBX
Wafer surface quality inspection W0059 EU5MWDX
Wafer surface quality inspection W0060 E85MWZX
Wafer surface quality inspection W0061 E15MVPX
Polyimide mask • Microsystems HD 4100 polyimide - negative tone, solvent developed, photodefinable polyimide • Steps: • Spinning • Baking • Exposition • Development • Silicon nitride deposition • Chemical activation of polyimide • Stripping • Advantage: • Silicon technology compatible • Perfect alignment • No residuals • Disadvantage: • Temperature sensitive process • Time consuming process • mechanical scratching of bonding pads
PECVD Plasma enhanced chemical vapor deposition Silicone oxide or silicone nitride formation Plasma power max 600 W at 187.5 kHz, max 300 W at 13.56 MHz plasma frequency Substrate temperature 100 up to 400 °C Layers contain hydrogen Oxford 80 (PECVD)
just deposited SixNy “chemically activated polyimide”
SU-8 photoresist composition: - Gamma Butyrolactone 22-60% - Up to 10 % Triarylsulfonium / Hexafluoroantimonate Salt (3.3% for SU-8/50) - Propylene Carbonate 1-5% - Epoxy Resin 35-75% - C - O SU-8 - epoxy-based negative photoresist Bisphenol A Novolak epoxy oligomer SU-8 crosslinking mechanism O OH O + CH2 O CH CH2 + R1 + H+ CH CH R1 R1 CH R1 CH CH2 R1 - H+ CH2 CH2 O
Al layer Sputtering system Leybold Z660 DC 50%, no sputter etching, 30 sec – the deposition time for every sputtering run, + cooling delay Total thickness: ~ 800 nm
Chip Pixel pad protection layer SU-8 photoresist SU-8 column aluminum deposition of Al layer Chip Cross-linked SU-8 photoresist
Development of SU-8 • Acetone • Acetone:IPA:H2O (1:1:2) • Acetone:IPA:H2O (1:1:1) • Acetone:IPA (1:1) • Microstrip 6001 • H2O • IPA • Acetone • Drying in the air
Summary • W0058 EW5MWBX (4 mm SixNy) in process • W0059 EU5MWDX (4 mm SixNy) broken • W0060 E85MWZX (8 mm SixNy) in process • W0061 E15MVPX (8 mm SixNy) requires the cleaning IZM-5 started: W0062 (4 mm SixNy) and W0063 (8 mm SixNy) Modified InGrid(mInGrid) - started