The process of creating a pattern on a wafer is known as lithography. Typically, light is shone through a mask onto a photoresist that coats the wafer. After exposure, the photoresist is “developed,” which removes the exposed part of the resist (or the unexposed resist if it is negative resist). A photoresist coat/bake/develop system — often called a “track system” is typically connected directly to the wafer exposure tool or wafer “stepper.”

The exposed wafer is then etched, where the photoresist acts as a barrier to the etching chemicals or reaction ions. The photoresist is then removed by stripping or “ashing.” In complex integrated circuits, a modern CMOS wafer will go through the photolithographic cycle up to 50 times, making lithography one most critical process step.

Increasingly smaller wavelengths of light have been used to create smaller dimensions. Complex mask designs have also evolved, such as optical proximity correction (OPC), to correct for optical effects. Mask-source optimization techniques have also been developed to correct for variations in the source and on the wafer.

A push to extreme ultra-violet (EUV) lithography has been under way for a decade or more, led by ASML Lithography. Alternatives have also been research and developed, including nano-imprint lithography (NIL), which uses stencils and multi e-beam (MEB) lithography, which uses a large bank of individually controlled electron beams to expose the wafer directly (no mask required). More recently, an interesting approach called directed self-assembly (DSA) has been studied, which enables very small dimensions. DSA uses a guide structure on the wafer and polymer-based chemicals to create regular lines with very small dimensions.

Check out our Lithography Topic Center for regular updates.

Additional Reading:

Feed-forward overlay control in lithography processes using CGS

Advanced lithography and electroplating approach to form high-aspect ratio copper pillars

SUBCATEGORIES:


SUPPLIERS


Astronics Test Systems: http://astronicstestsystems.com/



Nikon Precision Inc.: https://www.nikonprecision.com/



Sikama International Inc.: http://www.sikama.com



SK Commercial Construction, Inc.: http://www.skrcc.com/



Vistec Electron Beam GmbH: http://www.vistec-semi.com



ARTICLES



OEM Group announces post-dice clean solutions for plasma and laser dicing methods

09/28/2017  OEM Group announced today a post-dice clean solution on the proven Cintillio Batch Spray platform following plasma and laser dicing methods.

Understanding the impact of valve flow coefficient (Cv) in fluid systems

09/26/2017  Understanding the impact of valve flow coefficient (Cv) in fluid systems for microelectronics manufacturing.

New deionized water vapor delivery module from Brooks Instrument

09/11/2017  Brooks Instrument will be exhibiting at SEMICON Taiwan 2017 with a new vaporization product, mass flow controllers with high-speed EtherCAT, and a broad range of other mass flow meters, controllers and capacitance manometers for semiconductor manufacturing.

Analysis of global lithography metrology equipment market

08/25/2017  The lithography metrology equipment market is riding on the high wave of the semiconductor industry.

ALD tools evolve with industry needs

07/13/2017  Veeco Instruments (Veeco) recently announced that Veeco CNT -- formerly known as Ultratech/Cambridge Nanotech -- shipped its 500th Atomic Layer Deposition (ALD) system to the North Carolina State University.

SEMI and Solid State Technology announce 2017 “Best of West” Award finalists

06/28/2017  Each year at SEMICON West, the “Best of West” awards are presented by Solid State Technology and SEMI.

EV Group optimizes resist and lithographic processing for plasma dicing

06/20/2017  EVG resist processing and lithography systems provide pre-processing solution to enable complete damage-free advanced dry plasma dicing on thin semiconductor wafers.

SEMICON West preview: Equipment components and subsystems

06/08/2017  Attention turns to subcomponents to improve yields at advanced nodes.

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

03/08/2017  New IQ Aligner NT achieves double throughput and alignment accuracy over previous-generation platform; opens up new applications for EVG lithography solutions.

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.