Nav: Home

Irregular silicon wafer breakage studied in real-time by direct and diffraction X-ray imaging

March 03, 2016

Fracture and breakage of single crystals, particularly of silicon wafers, are multi-scale problems: the crack tip starts propagating on an atomic scale with the breaking of chemical bonds, forms crack fronts through the crystal on the micrometre scale and ends macroscopically in catastrophic wafer shattering.

Total wafer breakage is a severe problem for the semiconductor industry not only during handling but also during temperature treatments, leading to million-dollar costs per annum in a device production line. Knowledge of the relevant dynamics governing perfect cleavage along the {111} or {110} faces, and of the deflection into higher indexed {hkl} faces of higher energy, is scarce due to the high velocity of the process. Imaging techniques are commonly limited to depicting only the state of a wafer before the crack and in the final state.

A group of researchers demonstrates, for the first time, in situ high-speed crack propagation under thermal stress, imaged simultaneously in direct transmission and diffraction X-ray imaging [Rack, Scheel and Danilewsky (2016). IUCrJ, 3, 108-114; doi:10.1107/S205225251502271X]. The scientists show how the propagating crack tip and the related strain field can be tracked in the phase-contrast and diffracted images, respectively. Movies with a time resolution of microseconds per frame reveal that the strain and crack tip do not propagate continuously or at a constant speed. Jumps in the crack tip position indicate pinning of the crack tip for about 1-2 ms followed by jumps faster than 2-6 m s-1, leading to a macroscopically observed average velocity of 0.028-0.055 m s-1. The results also give a proof of concept that the described X-ray technique is compatible with studying ultra-fast cracks up to the speed of sound.

Rack et al. comment, "We are only at the beginning of studying ultra-fast crack propagation in single-crystalline materials in real time".

International Union of Crystallography

Related Chemical Bonds Articles:

Chemical evolution -- One-pot wonder
Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth -- under the same environmental conditions.
What happens when you explode a chemical bond?
Light-induced breakage of chemical bonds can lead to damage in the body and environment, but techniques for studying this photochemical reaction have been limited to before and after snapshots.
Fiber-optic probe can see molecular bonds
Engineers at UC Riverside have developed the world's first portable, inexpensive, optical nanoscopy tool that integrates a glass optical fiber with a silver nanowire condenser.
Chemical juggling with three particles
Chemists from the University of Bonn and their US colleagues at Columbia University in New York have discovered a novel mechanism in catalysis.
Chemical synthesis of nanotubes
For the first time, researchers used benzene -- a common hydrocarbon -- to create a novel kind of molecular nanotube, which could lead to new nanocarbon-based semiconductor applications.
Chemical catalyst turns 'trash' into 'treasure,' making inert C-H bonds reactive
The Nature paper is the latest in a series from Emory University demonstrating the ability to use a dirhodium catalyst to selectively functionalize C-H bonds in a streamlined manner, while also maintaining virtually full control of the three-dimensional shape of the molecules produced.
Carnegie Mellon researchers probe hydrogen bonds using new technique
Researchers at Carnegie Mellon University have used nuclear resonance vibrational spectroscopy to probe the hydrogen bonds that modulate the chemical reactivity of enzymes, catalysts and biomimetic complexes.
Mothers whose responses to infants' facial cues increase report stronger bonds with babies
A new study forthcoming in the journal Child Development examined whether pregnancy changes mothers' neural sensitivity to infants' facial cues, and whether such changes affect mother-infant bonding.
Controlling chemical reactions near absolute zero
EPFL chemists have demonstrated complete experimental control over a chemical reaction just above absolute zero.
RUDN chemists created a precise model of chemical bonds in diazone dyes
Chemists from RUDN carried out detailed analysis of the nature of intermolecular bonds between nitrogen and chlorine in the molecules of azo dyes and defined their photochromic properties.
More Chemical Bonds News and Chemical Bonds Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.