A Low-Cost Passive Alignment System for Micro and Nano Imprinting

Technology #15820

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Inventors
Professor Martin Culpepper
Department of Mechanical Engineering, MIT
External Link (lmp.mit.edu)
Sourabh Saha
Department of Mechanical Engineering, MIT
Managed By
Ben Rockney
MIT Technology Licensing Officer
Patent Protection

System for passive alignment of surfaces

US Patent 8,834,146
Publications
An automated stage for scalable imprinting of DNA nanowires based on a self-aligning technique
ASME IMECE, (2012)

Applications

Alignment system for micro and nano imprinting, such as DNA combing and imprinting (DCI)

Problem Addressed

During imprinting of patterns from a stamp onto a substrate surface, conformal contact is necessary to ensure that pattern transfer is successful over the entire stamp.  However, such contact is hindered by the initial angular misalignment between the surfaces.  In real systems, this misalignment is inevitable and arises due to the two surfaces being non-parallel.  Therefore, alignment systems that can orient the surface parallel to each other while bringing them in contact are necessary during imprinting.  Current alignment systems are one of two types: (1) active systems that use feedback control; (2) manual techniques that rely on the deformability of a soft stamp.  For micro/nano imprinting, active systems are expensive and become a barrier to entry for small businesses and academic laboratories.  Manual techniques are inappropriate for imprinting fragile features because micro/nano features on the stamp are squished by conformal contact.  Thus, there is a technology gap that can be filled by developing high-performance and low-cost alignment system.

Technology

This invention presents an alternate strategy wherein alignment is achieved via kinematics with an easy-to-manufacture, low-cost, and passive system.  In this system, kinematic constraints are implemented by supporting the stamp on a set of three smooth spherical balls.  When the misaligned bottom surface is moved up towards the stamp, the stamp first loses contact with one ball and gradually comes into contact with the substrate along an edge.  With further actuation, the stamp loses contact with the second ball and then the third ball, whereby the stamp then “sits” entirely on top of the substrate.  As the alignment process is decoupled from the contact force, fragile features can be imprinted by independently tuning the contact force to infinitesimally small values.

Advantages

  • Eliminates expensive sensors
  • Reduces the number of actuators by a factor of three
  • Enables using low-performance actuators to achieve the same alignment
  • Reduces the cost by at least 100 times without sacrificing alignment accuracy