SU-8 - Nikhef

Report
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
Thickness 725 µm
48.22 mm
CHIPEDGE
48.22 mm
16120 mm
TimePix chip
Pixel Row 255
57.7
mm
28.3
mm
Pixel Row 254
Pixel Row 253
14111 mm
Pixel Row 1
55 mm
Pixel Row 0
55 mm
10 mm
20 mm
20 mm
Detector Guard
Ring Row
20 mm
20 mm
Snake Top Row
CHIPEDGE
Column 255
Column 254
Column 253
Column 252
Column 251
Column 4
Column 3
Column 2
Column 1
Column 0
256 x 256 pixels
CHIPEDGE
Snake Bottom Row
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 - epoxy-based negative photoresist
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
Bisphenol A Novolak epoxy oligomer
-O
SU-8 crosslinking mechanism
O
O
R1
CH
OH+
+ H+
CH2
R1
+ R1
CH
CH
CH2
O
CH2
R1
- H+
CH2
CH
CH
CH2
O
R1
SU-8 layer map
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
1
x
2
x
3
x
4
x
5
x
6
x
7
x
8
x
9
x
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
x x x x x x x x x x x x x
deposition of Al layer
Chip
Chip
Pixel pad
protection layer
SU-8 photoresist
SU-8 column
aluminum
Cross-linked SU-8 photoresist
Development of SU-8
1.
2.
3.
4.
5.
6.
7.
8.
9.
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
Standard development
Extra cleaning
O2 plasma cleaning
O2 plasma cleaning
O2 plasma cleaning (long time)
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

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