A practical method for greatly enhancing the strength of the modulated signal from laser probing of IC's is described. An IC device under test (DUT) is scanned with two spatially separated laser beams. The output from a single laser source is split into two separate components with each focused on different areas of the DUT. The separation between the beams and their intensity is adjustable to maximize the strength of the modulated return signal. Typically a NIR laser is used with flip-chip IC devices to account for the band-gap (transmission) characteristics of the substrate material. Upon reflection from the DUT, the reflected beams are recombined to interfere with one another. The phase difference of the two beams is adjustable to gain maximum interference. This signal is then processed to obtain the waveforms that correspond to the actions of the active gates and nodes as the chip is electronically cycled through its prescribed test loop. This method significantly improves the signal to noise ratio and reduces the time it takes to acquire a useful voltage waveform.
An optical probe system for probing an electronic device includes a sample plate configured to hold a target device comprising an integrated circuit, a temperature control chamber configured to hold a fluid to control the temperature of the target device, a first optical objective system that can collect reflected or emitted light from the integrated circuit in the target device, a rotational stage including ports that can hold the optical objective systems, a vertical translation stage that can move the first optical objective system in a vertical direction substantially perpendicular to the sample plate, and an x-y translation stage that can move the first optical objective system in horizontal directions. A portion of the first optical objective system is moved through the temperature control chamber to allow the first optical objective system to focus at the target device.
An optical probe system includes a sample plate for holding a target device comprising an integrated circuit, and a rotational stage that includes a plurality of ports configured to receive and hold a plurality of optical objective systems that can collect reflected or emitted light from the integrated circuit. At least one of the ports includes a centering plate mounted on the rotational stage and configured to conduct a translational movement on the rotational stage. The port also includes a gimbal plate mounted on the centering plate and that can be tilted relative to the centering plate. A first optical objective system that is mounted on the gimbal plate can be centered by the center plate and aligned by the gimbal plate.
An optical probe system for probing an electronic device includes a sample plate that can hold a target device comprising an integrated circuit, an optical objective system that can collect reflected or emitted light from the integrated circuit in the target device, and a temperature control chamber that can hold a fluid to control the temperature of the target device.
A method for detecting ultra-fine features of an integrated circuit (IC) on a semiconductor substrate is disclosed. The semiconductor substrate comprises an IC fabricated by 22 nanometer or smaller scale semiconductor micro-fabrication process. The integrated circuit includes circuit features parallel to a circuit horizontal direction or a circuit vertical direction. The method includes focusing an incident light to produce a focused light spot on a portion of the IC. The incident light is linearly polarized in a linear polarization substantially parallel to the circuit horizontal direction. The method includes detecting reflected light from the portion of the IC, producing a relative movement between the focused light spot and the IC to allow the focused light to illuminate different portions of the IC, obtaining an image of the IC using signals of the reflected light detected from different locations of the integrated circuit, and detecting IC features in the image.
An optical probe system for probing an electronic device includes a sample plate that can hold a target device comprising an integrated circuit, an optical objective system that can collect reflected or emitted light from the integrated circuit in the target device, and a temperature control chamber that can hold a fluid to control the temperature of the target device.
A method for detecting ultra-fine features of an integrated circuit (IC) on a semiconductor substrate is disclosed. The semiconductor substrate comprises an IC fabricated by 22 nanometer or smaller scale semiconductor micro-fabrication process. The integrated circuit includes circuit features parallel to a circuit horizontal direction or a circuit vertical direction. The method includes focusing an incident light to produce a focused light spot on a portion of the IC. The incident light is linearly polarized in a linear polarization substantially parallel to the circuit horizontal direction. The method includes detecting reflected light from the portion of the IC, producing a relative movement between the focused light spot and the IC to allow the focused light to illuminate different portions of the IC, obtaining an image of the IC using signals of the reflected light detected from different locations of the integrated circuit, and detecting IC features in the image.
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