Light-induced voltage alteration for integrated circuit analysis
First Claim
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1. An apparatus for analyzing an integrated circuit formed from a semiconductor, the apparatus comprising:
- (a) a stage for holding the integrated circuit and making a plurality of electrical connections thereto;
(b) at least one source of light having a photon energy near or above an energy bandgap of the semiconductor;
(c) a means for focusing the source of incident light to illuminate a portion of a surface of the integrated circuit, the incident light producing a photogenerated electrical current in the integrated circuit;
(d) means for scanning the focused source of incident light over the surface of the integrated circuit, the scanning means further comprising a position signal;
(e) a constant-current electrical source connected to the stage to supply power to the integrated circuit, the constant-current source further comprising a signal voltage that changes in response to the photogenerated electrical current in the integrated circuit produced by the focused source of incident light, whereby the integrated circuit is analyzed.
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Abstract
An apparatus and method are described for analyzing an integrated circuit (IC), The invention uses a focused light beam that is scanned over a surface of the IC to generate a light-induced voltage alteration (LIVA) signal for analysis of the IC, The LIVA signal may be used to generate an image of the IC showing the location of any defects in the IC; and it may be further used to image and control the logic states of the IC. The invention has uses for IC failure analysis, for the development of ICs, for production-line inspection of ICs, and for qualification of ICs.
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Citations
25 Claims
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1. An apparatus for analyzing an integrated circuit formed from a semiconductor, the apparatus comprising:
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(a) a stage for holding the integrated circuit and making a plurality of electrical connections thereto; (b) at least one source of light having a photon energy near or above an energy bandgap of the semiconductor; (c) a means for focusing the source of incident light to illuminate a portion of a surface of the integrated circuit, the incident light producing a photogenerated electrical current in the integrated circuit; (d) means for scanning the focused source of incident light over the surface of the integrated circuit, the scanning means further comprising a position signal; (e) a constant-current electrical source connected to the stage to supply power to the integrated circuit, the constant-current source further comprising a signal voltage that changes in response to the photogenerated electrical current in the integrated circuit produced by the focused source of incident light, whereby the integrated circuit is analyzed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for analyzing an integrated circuit formed from a semiconductor, comprising the steps of:
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(a) placing at least one integrated circuit on a stage, the stage making a plurality of electrical connections to the integrated circuit; (b) irradiating a portion of a surface of the integrated circuit with a focused source of incident light, the source of incident light having a photon energy near or above an energy bandgap of the semiconductor. (c) scanning the focused source of incident light over the surface of the integrated circuit with a scanning means, the scanning means providing a position signal; (d) supplying power to the integrated circuit with a constant-current electrical source connected to the stage, the constant-current source providing a signal voltage that changes in response to the photogenerated electrical current in the integrated circuit produced by the focused source of incident light, whereby the integrated circuit is analyzed. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification