Charge Induced Voltage Alteration
Encyclopedia
Charge induced voltage alteration (CIVA) is a technique which uses a scanning electron microscope
to locate open conductors
on CMOS
integrated circuit
s. This technique is used in semiconductor
failure analysis
.
buildup on conductors which are disconnected from the remainder of the circuit (floating conductors). If a CMOS device is under active bias, the presence of open conductors may not prevent the circuit from operating at low clock frequencies as the result of quantum tunneling effects. By injecting charge into floating conductors that are operating in this tunneling mode, it is possible to produce additional loading which can be detected by monitoring the power supply current
. These changes in supply current may be associated with the visual image of the device at the coordinates at which the change was detected. The result is a scanning electron microscope image which has an overlay of the floating conductors superimposed on it.
Scanning electron microscope
A scanning electron microscope is a type of electron microscope that images a sample by scanning it with a high-energy beam of electrons in a raster scan pattern...
to locate open conductors
Electrical conductor
In physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...
on CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s. This technique is used in semiconductor
Semiconductor device
Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced thermionic devices in most applications...
failure analysis
Failure analysis
Failure analysis is the process of collecting and analyzing data to determine the cause of a failure. It is an important discipline in many branches of manufacturing industry, such as the electronics industry, where it is a vital tool used in the development of new products and for the improvement...
.
Theory of operation
The scanning of an electron beam across the surface of the device may result in additional chargeElectric charge
Electric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
buildup on conductors which are disconnected from the remainder of the circuit (floating conductors). If a CMOS device is under active bias, the presence of open conductors may not prevent the circuit from operating at low clock frequencies as the result of quantum tunneling effects. By injecting charge into floating conductors that are operating in this tunneling mode, it is possible to produce additional loading which can be detected by monitoring the power supply current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
. These changes in supply current may be associated with the visual image of the device at the coordinates at which the change was detected. The result is a scanning electron microscope image which has an overlay of the floating conductors superimposed on it.