Wafers need to be inspected at many stages throughout the manufacturing process. Particles and defects need to be detected and classified. Features need to be measured in both the x, y and z direction (critical dimensions and film thickness, for example). Film stoichiometry needs to be measured. Wafer warpage and bow must be evaluated and compensated for. Film stress (either tensile or compressive) is another important measurand as is dopant concentration, adhesion, and dozens if not hundred of other parameters. Variations across the wafer, within each die and die-to-die are also important.

Wafer inspection — also called metrology — is mostly used for process control, to make sure processes are not drifting out of control, As such, measurements are made after each process step — or more infrequently if at all possible since there is a cost associated with every inspection step in terms of capital equipment required, reduced throughput and added particles from increased handling.

Of course, more advanced characterization techniques are also needed for process development and failure analysis.

New inspection challenges include the need to measure more complex device structures such as those found in FinFETs and 3D NAND. The industry is also pushing a wide array of new materials into production, which brings a new set of challenges since each type of material has unique properties when it comes to reflection, refraction, adhesion, stress, etc.

The push to smaller dimensions and thinner films means smaller defects and variations become more important, which often pushes the accuracy, resolution and repeatability limits of today’s measurement tools.

The most common type of wafer inspection tool is the optical microscope. Although still used today for macro inspection, the very small dimension on today’s wafers can only be measured by more advanced means, most notably the scanning electron microscope and the transmission electron microscope. Other commonly used tools include ellipsometers to measure film thickness.

For failure analysis, even more sophisticated surface analysis tools are required, including  ESCA, Auger, EDAX, and Rutherford Backscattering (RBS), among many others.

SUPPLIERS


Eastern Applied Research, Inc.: www.easternapplied.com
Product announcements:



Akrometrix, LLC: www.akrometrix.com



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Berliner Glas KGaA Herbert Kubatz GmbH & Co.: http://www.berlinerglas.com



Cascade Microtech: http://www.cascademicrotech.com



HEIDENHAIN CORPORATION: http://www.heidenhain.com



Microtronic, Inc.: http://www.microtronic.com



NanoFocus AG: www.nanofocus.com



Prior Scientific, Inc.: http://www.prior.com/



Rudolph Technologies, Inc.: http://www.rudolphtech.com



Semitracks, Inc.: http://www.semitracks.com



TSI Inc. : http://www.tsi.com/



Wright Williams & Kelly, Inc.: http://wwk.com



ARTICLES



Global semiconductor wafer-level equipment revenue to grow 11% in 2016

04/20/2017  Worldwide semiconductor wafer-level manufacturing equipment (WFE) revenue totaled $37.4 billion in 2016, an 11.3 percent increase from 2015, according to final results by Gartner, Inc.

3D-Micromac receives large volume orders from solar industry for its microCELL TLS system

04/18/2017  3D-Micromac AG today announced that the total received order volume for its microCELL TLS high-throughput half-cell cutting tools tops 1.5 GW for tool deliveries in 2017 to date.

EVG breaks speed and accuracy barrier in mask alignment lithography for semiconductor packaging

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Record spending for fab equipment expected in 2017 and 2018

03/07/2017  Today, SEMI announced updates to its World Fab Forecast report, revealing that fab equipment spending is expected to reach an industry all-time record − more than US$46 billion in 2017.

Global MEMS manufacturer selects ULVAC Technologies' plasma ashing system

03/01/2017  ULVAC Technologies, Inc. has been selected by a global MEMS inertial sensor manufacturer to deliver an ULVAC ENVIRO-1Xa advanced plasma ashing system for running critical low-temp descum processes and high-temp bulk photoresist strip processes.

ClassOne initiative aims to reduce CoO in ≤200mm copper plating

02/22/2017  ClassOne Technology announced a new company-wide initiative to reduce costs of operation (CoO) in copper plating processes.

SEMI appoints Ajit Manocha as president and CEO

02/21/2017  SEMI today announced the appointment of Ajit Manocha as its president and CEO.

Executive viewpoints: 2017 outlook

01/25/2017  Each year, Solid State Technology turns to industry leaders to hear viewpoints on the technological and economic outlook for the upcoming year. Read through these expert opinions on what to expect in 2017.

North American semiconductor equipment industry posts November 2016 book-to-bill ratio of 0.96

12/16/2016  A book-to-bill of 0.96 means that $96 worth of orders were received for every $100 of product billed for the month.

Murphy, Choh and Pilla join ClassOne Technology's Board of Advisors

12/01/2016  ClassOne Technology, manufacturer of advanced wet processing equipment for ≤200mm substrates, announced the formation of a Board of Advisors.

Managing particle flows in process exhaust for safety and profitability

10/28/2016  Solid particles in the abatement exhaust must be properly managed, and in some cases, substantially reduced from the gas stream before it is released into the environment.

Lam Research introduces dielectric atomic layer etching capability for advanced logic

09/07/2016  Lam Research Corp., an advanced manufacturer of semiconductor equipment, today announced that it is expanding its atomic layer etching (ALE) portfolio with the addition of ALE capability on its Flex dielectric etch systems.