Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New infrared tool measures silicon wafer thickness

15.07.2005


In the last few years, semiconductor circuit features have shrunk to sub-100 nanometer (nm) dimensions, while the size of the thin silicon wafers that these circuits are constructed on has grown from 200 millimeters (mm) to 300 mm (about 12 inches). The payoff is a higher yield of finished devices from fewer wafers.


A new NIST calibration system under development used infrared laser light to precisely measure the thickness of 300 millimeter silicon wafers. Changes in color within the spatial map above represent changes in wafer thickness. Green represents the average wafer thickness, while red, orange and yellow areas are thicker, and turquoise and blue areas are thinner. Credit: Q. Wang, U. Griesmann/NIST



The tough part, however, is to make wafers substantially larger while simultaneously meeting higher quality control specifications. The optics and materials for "printing" nanoscale circuit lines require that the wafers used are perfectly flat and of uniform thickness. To help the semiconductor industry meet its 2010 quality control roadmap goals, researchers at the National Institute of Standards and Technology (NIST) recently developed a new instrument that accurately measures differences in thickness across a 300 mm wafer with an excellent repeatability of 5 nm. The researchers hope the tool, with further refinements, will allow them to establish a new calibration service for "master wafers" used in the industry to measure wafer thickness.

The NIST researchers will describe the instrument, the Improved Infrared Interferometer, or IR3 for short, at a technical conference* in late July. Like all interferometers, the IR3 uses intersecting waves of light to create interference patterns, which in turn can be used as a ruler to measure nanoscale dimensions. While most interferometers use red laser light, the IR3 uses infrared laser light. And unlike visible light, these much longer wavelengths pass right through a silicon wafer. This means that IR3 can illuminate the top and bottom on a 300 mm wafer and produce a detailed spatial map of differences in thickness in one pass. Conventional tools require spinning the wafer and measuring at multiple locations.


The NIST researchers make precision measurements of the wafer’s index of refraction--the amount that light is "bent" as it passes through the silicon--as a critical step in correctly interpreting the interference patterns. Increased precision in the refractive index measurement will be necessary before "absolute" measurements of thickness rather than relative differences will be possible with the new instrument.

Gail Porter | EurekAlert!
Further information:
http://www.nist.gov

More articles from Physics and Astronomy:

nachricht Tracing aromatic molecules in the early universe
23.03.2017 | University of California - Riverside

nachricht New study maps space dust in 3-D
23.03.2017 | DOE/Lawrence Berkeley National Laboratory

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>