Semiconductor Analysis
The electronics industry relies heavily upon lasers for semiconductor failure analysis (SFA) to optimise manufacturing processes and accelerate the development of disruptive technologies which are shaping emerging industries.
Photonics integrated circuits (PICs), for instance, uses a laser source to emit light and power components, rather than electricity. Such components parts are vital in the adoption of connectivity and autonomous sensing applications which are driving Industry 4.0.
However, global chip shortages and stockpiling place an even greater emphasis upon optimising semiconductor failure analysis. Determining the root cause more efficiently reduces ‘end-of-life’ testing, minimises waste and ultimately, maximises future manufacturing yield.
Photonics Integrated Circuits
Ultrashort-pulse lasers have been widely used to interrogate the next generation of photonics integrated circuits across a broad range of wavelengths.
Chromacity’s optical parametric oscillator (OPO), for instance, is a tunable light source which is suitable for generating two-photon absorption, or down-conversions, in PICs and waveguides without unwanted four wave mixing effects.
Optical Fault Isolation
Between 1250 nm – 1310 nm wavelengths, Chromacity’s femtosecond lasers deliver 80 fs pulse durations and excellent beam quality for optical fault isolation techniques, including Soft Defect Localization (SDL) and Laser Assisted Device Alteration (LADA).
Soft defects are characteristic of failures found in partially functional integrated circuits. SDL imaging systems apply laser-scanning methods, to generate localised heating and find defects. In contrast, LADA is a laser-based timing analysis technique which uses short wavelengths to generate photocarriers in silicon, without resulting in localised heating of the device.
Chromacity’s ultrashort-pulse systems can be deployed during 2P LADA techniques which generate two-photon absorption-induced single event upsets (SEU) in micro-electronic devices, such as microprocessors or power transistors.
Two-Photon Optical Beam Induced Current
Two-Photon Optical Beam Induced Current (TOBIC) is a similar laser-scanning method for imaging integrated circuits. The technique uses ultrashort-pulse lasers to induce a photocurrent which is subsequently mapped to generate an image.
With one-photon excitation, an ultrafast laser (such as the Chromacity 1040 nm) can penetrate through silicon substrate and excite carriers in the circuit to generate the photocurrent.
However, when the substrate is several hundred microns thick, TOBIC imaging ensures that a beam of light is sufficiently transmitted with enough absorption to create carriers in the circuits required to generate higher resolution images. TOBIC imaging typically occurs around 1250 – 1550 nm and the beam is easily transmitted through the silicon band gap (which is greater than 1050 nm). The only absorption occurs at the beam focus where the intensity is high enough to cause two-photon absorption.
By mapping the photocurrent as a function of beam position, TOBIC can generate depth-sensitive or 3D imagery using Chromacity’s femtosecond fiber lasers
Photomask Defects
The slightest defect on a photomask can inhibit the performance of an integrated circuit and the miniaturisation of transistors has only contributed towards the complexity of developing and transferring photomasks onto silicon wafers.
Picosecond ultrasonics has become a widely used metrology tool in the semiconductor device industry. It provides an accurate method for the measurement of the thickness of thin films and can determine the quality of the bonding between a film and a substrate. The overlay and alignment of a lithographically defined pattern on top of an underlying layer is fundamental to device performance.
The Chromacity 520 nm is ideally suited for ultrasonics metrology. The compact laser housing enables simple system integration, and fiber delivery ensures stable average powers up to 1.5 W.
For more information about how ultrashort-pulse lasers are used to conduct semiconductor failure analysis (SFA), contact one of our photonics experts: sales@chromacitylasers.com