This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.
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In integrated circuits (ICs), conductive lines provide electrical interconnection among different parts of the ICs, devices, and the outside. The main applications of metallization are classified by gate, contact, and interconnection. Polysilicon and silicides are commonly applied as gates and interconnects in MOS devices. Aluminum, copper, tungsten, silver, titanium, platinum, gold, and palladium are used as these types of contacts, connections, and/or interconnection to external components.
Table 2037a. Metallization selections in ICs.
Application |
Selection |
Gates, interconnection, and
contacts |
Polysilicon, refractory metal silicides (e.g. MoSix, TaSix, WSix, and TiSix), nitrides,aluminum, copper, and/or refractory metals. |
Diffusion barrier layer |
Ti, TiN, Ta, TaN, Ti-W alloy, and/or silicides |
Top level |
Aluminum, and/or copper |
Metallization
on silicon |
Silicides, tungsten, aluminum, and/or copper |
Table 2037b. Properties of interconnect materials.
Silicides |
Thin film
resistivity
(μΩ − cm) |
Thermal expansion (ppm/°C) |
Si consumption (nm Si/nm Silicide) |
Melting point (°C) |
|
|
|
Cu |
1.7-2.0 |
|
|
1084 |
|
|
|
Al |
2.7-3.0 |
|
|
660 |
|
|
|
W |
8-15 |
|
|
3410 |
|
|
|
PtSi |
28-35 |
|
|
1229 |
|
|
|
NiSi |
14-20 |
|
|
992 |
|
|
|
TiN |
50-150 |
|
|
~2950 |
|
|
|
Ti30W70 |
75-200 |
|
|
~2200 |
|
|
|
Heavily
doped polysilicon |
500-1000 |
|
|
1410 |
|
|
|
Tetragonal WSi2 |
50-120 |
6-8 |
0.98 |
2165 |
|
|
|
CoSi2 |
18-25 |
~10 |
1.03 |
1325 |
|
|
|
MoSi2 |
20-100 |
~8 |
0.99 |
1980 |
|
|
|
TaSi2 |
10-50 |
8-11 |
0.92 |
2200 |
|
|
|
C54-TiSi2 |
12-24 |
12 |
0.904 |
1540 |
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