Semiconductor Failure Analysis

Lasers for Semiconductor Failure Analysis

The electronics industry relies heavily upon laser-assisted 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 Localisation (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.

Silicon Wafers
Between 1250 nm – 1310 nm wavelengths, Chromacity’s femtosecond lasers deliver 80 fs pulse durations and excellent beam quality for optical fault isolation techniques.
Chromacity 1280 nm

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

Chromacity OPO
Chromacity 1040
Chromacity 520

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.

 

The Chromacity 520 nm can be used to detect photomask defects using lithography. 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

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