TY - JOUR
T1 - Platinum patterning by a modified lift-off technique and its application in a silicon load cell
AU - Tong, H.D.
AU - Zwijze, R.A.F.
AU - Berenschot, J.W.
AU - Wiegerink, R.J.
AU - Krijnen, G.J.M.
AU - Elwenspoek, M.C.
PY - 2001/4/3
Y1 - 2001/4/3
N2 - In micro-electromechanical systems (MEMS) and micro-electronic devices there has
been a strong demand for electrode materials which can survive in highly oxidizing and
high-temperature environments. Platinum (Pt) is a good candidate for this, because it
combines several attractive properties: low electrical resistance, high melting point and
high chemical stability. However, the chemical stability is a problem for patterning Pt by
wet chemical or dry etching. Standard lift-off seems to be a solution to this problem. A big
problem in using standard lift-off is that platinum particles or wing tips (ears) may remain
at the edges after lift-off. These wing tips protrude from the surface and may cause short
circuits with an opposite electrode placed within 1 μm. Some authors reported briefly on
a modified lift-off technique to overcome this problem. Before deposition, a resist is
patterned on an insulator to define openings where the metal is to be deposited. Afterwards,
a small cavity is etched in the insulator, which is mostly SiO2. The cavity facilitates
the separation of the metal on the resist and the metal in the cavity. In this study the effect
of cavity depth and sputtered metal thickness on wing tip formation is investigated. In
addition, surface roughness, resistance and hillock formation of the as-deposited metals are
measured. The modified lift-off technique has succesfully been applied in a silicon load
cell with Ti/Pt electrodes.
AB - In micro-electromechanical systems (MEMS) and micro-electronic devices there has
been a strong demand for electrode materials which can survive in highly oxidizing and
high-temperature environments. Platinum (Pt) is a good candidate for this, because it
combines several attractive properties: low electrical resistance, high melting point and
high chemical stability. However, the chemical stability is a problem for patterning Pt by
wet chemical or dry etching. Standard lift-off seems to be a solution to this problem. A big
problem in using standard lift-off is that platinum particles or wing tips (ears) may remain
at the edges after lift-off. These wing tips protrude from the surface and may cause short
circuits with an opposite electrode placed within 1 μm. Some authors reported briefly on
a modified lift-off technique to overcome this problem. Before deposition, a resist is
patterned on an insulator to define openings where the metal is to be deposited. Afterwards,
a small cavity is etched in the insulator, which is mostly SiO2. The cavity facilitates
the separation of the metal on the resist and the metal in the cavity. In this study the effect
of cavity depth and sputtered metal thickness on wing tip formation is investigated. In
addition, surface roughness, resistance and hillock formation of the as-deposited metals are
measured. The modified lift-off technique has succesfully been applied in a silicon load
cell with Ti/Pt electrodes.
M3 - Article
SN - 0914-4935
VL - 13
SP - 235
EP - 246
JO - Sensors and materials
JF - Sensors and materials
IS - 4
ER -