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 From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>