An integrated circuit or computer chip consists of a Si wafer with patterns of copper wires attached to the surface. During normal operation the chip may heat up and cause debonding of the Cu wires from the Si surface. This is because:
1. The Si expands more when it is heated
2. The Cu is an electrical conductor and Si is an insulator
3. The Si is a semiconductor
4. The Cu has a higher coefficient of thermal expansion
2007-09-24 05:36:47 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
4. The copper expands faster than the silicon and breaks the bond between the contact and the board.
2007-09-24 06:05:37 · answer #1 · answered by Brian K² 6 · 0⤊ 0⤋
4.
This why copper interconnects are not used inside ICs -- they use aluminum and other alloys. IBM apparently solved the problem (since the year 2000) with a certain copper alloy, but it is not widely used. At least I haven't heard much about it in recent years.
In order to get keep up with higher densities and higher speeds in future ICs, some experts believe using copper is the only way to go, but they still have this fundamental problem to deal with.
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2007-09-24 13:42:53 · answer #2 · answered by tlbs101 7 · 0⤊ 0⤋