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Optical Lithography

EV Group offers a complete portfolio to support the wide range of possibilities inherent in lithography technology.

Introduction

Optical lithography, the structuring of photosensitive materials by mask-defined light for subsequent semiconductor processes, is a well-known and established technology. Today’s main requirements for optical lithography are defined by several key parameters. Sub-micron alignment accuracy, controlled uniform proximity gap between mask and wafer, as well as a clearly defined and precisely controlled exposure spectrum corresponding to the resist sensitivity, are among the most important criteria taken into account. Additionally, EVG´s customer-focused approach includes customized solutions for dedicated process needs. Understanding special requirements and having the flexibility to adapt our systems accordingly are among the unique core competences that EVG brings to the marketplace while constantly enhancing its lithography portfolio.

Over the years, optical lithography has continued to evolve to meet the scaling requirements for new semiconductor device designs.. EVG has also continuously looked ahead at future market requirements and developed new innovations in the field of optical lithography technology – from the invention of the world’s first double-sided mask aligner in 1985 up to today, with the Q Aligner NT achieving a top-side alignment down to 250 nm. Furthermore, EVG has implemented many advanced alignment features, such as runout control with temperature-controlled toolset, automatic cross correction, full clearfield mask movement, edge alignment and dynamic alignment. The latest implemented technology in EVG’s mask alignment product family is UV-LED technology, which gives users much more flexibility for their applications in terms of UV exposure spectrum setup, as spectral lines are individually tunable and special optical filters are no longer required. Maintenance of UV-LED lamp houses is also minimized. Further capabilities such as bond, transmissive or reflective IR alignment, as well as EVG’s proprietary SmartNIL technology, make EVG’s mask aligners very well equipped and advanced. This technology is well-established in the worldwide market today, covering all essential steps and able to serve various applications, such as wafer bumping, creation of redistribution layer (RDL) and via etching masks, via bottom opening processes, as well as lithography performed on thin or temporary bonded wafers. Such systems can be configured in semi-automated configurations for R&D as well as fully automated system configurations running cassette-to-cassette processes for high-volume production.

Features

  • Alignment modes
    • Top-side alignment
    • Bottom-side alignment
    • IR alignment: transmissive or reflective
    • Bond alignment
    • NIL alignment
  • Exposure source
    • Mercury light source
    • UV LED light source
  • Exposure setup
    • Vacuum contact | Hard contact | Soft contact | Proximity mode
    • Flex mode allowing stage/mask movement during exposure
  • Wedge compensation assuring uniform exposure results
    • Fully automatic – SW controlled with various control options
    • Contactless with proximity spacers
    • Recipe controlled contact force [5 N – 80 N]
  • Various advanced alignment features using sophisticated algorithms for overall alignment improvement down to 250 nm, offset correction, runout control or edge alignment
  • System control including file sharing and back-up solution, un-limited number of recipes, multi-language user GUI and support, real-time remote access, diagnostics and troubleshooting
  • Industrial automation features
    • Cassette, SMIF, FOUP, SECS/GEM, thin, bowed, warped, edge wafer handling
  • Nanoimprint lithography technology capability
  • Smart process control and data analysis features including integrated analysis features for processes and machine control, parallel task/queueing task processing feature, equipment and process performance tracking feature, smart handling, occurrences and alarm analysis together with smart maintenance management and tracking

Figures

High depth-of-focus exposure on EVG®620 NT of KOH etched cavities with a depth of 150 µm.
High depth-of-focus exposure on EVG®620 NT of KOH etched cavities with a depth of 150 µm.
MEMS structures patterned in 20 µm thick resist.
MEMS structures patterned in 20 µm thick resist.
Black resist lithography.
Black resist lithography.
Black resist lithography for optical MEMS, light shielding or projection applications.
Black resist lithography for optical MEMS, light shielding or projection applications.
High-aspect-ratio pillars for cell sorting and microfluidic applications, 100 µm thick resist patterning on IQ Aligner® NT.
High-aspect-ratio pillars for cell sorting and microfluidic applications, 100 µm thick resist patterning on IQ Aligner® NT.
Bottom opening of a coated TSV combining NanoSpray™ technology and exposure on EVG®6200 NT.
Bottom opening of a coated TSV combining NanoSpray™ technology and exposure on EVG®6200 NT.

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