Controlling Stamp Deformation in Microcontact Printing for High Quality Pattern Transfer

Technology #15681

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Geometry of actuator in (a) neutral and (b) energized states.Closed loop feedback control of stamp contact pattern using electrostatic actuators for local stamp control and optical sensing to determine the feedback variable.
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Inventors
Professor David Hardt
Department of Mechanical Engineering, MIT
External Link (meche.mit.edu)
Muhammad Hawwa
King Fahd University of Petroleum and Minerals
Joseph Petrzelka
Lab for Manufacturing & Productivity, MIT
Brian Anthony
Department of Mechanical Engineering, MIT
Hussain Al-Qahtani
King Fahd University of Petroleum and Minerals
Hassen Ouakad
King Fahd University of Petroleum and Minerals
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Actuation and Control of Stamp Deformation in Microcontact Printing

US Patent Pending 2014-0037909

Microcontact printing is a versatile process to create micro- and nano-scale patterns using an elastomeric stamp. The inventors have developed a method for local actuation and control of elastomeric stamps which allows feedback control of stamp deformation for high quality printing of sensitive stamp patterns.

Application

This technology enables high quality pattern transfer, especially in roll-to-roll soft lithography or microcontact printing. Continuous stamps with precise dimensional control may be used to print nanowire grids in a robust manner for photovoltaic systems, to print electronics on flexible substrates in a high speed fashion for low cost sensors and displays, and to create nanoscale patterns which can greatly increase heat transfer rates and charge capture for power generation, energy storage and solar power technologies.

Problem Addressed

During microcontact printing, selective contact between the substrate and the micro- or nano-scale features on the stamp results in transfer of a molecular or fluid ink. Deformations in the soft elastomeric stamp - which can include sidewall collapse, roof collapse and buckling—occur at a critical collapse pressure. Thus, controlling the pressure on the stamp is imperative to avoiding undesired stamp deformation and obtaining a high quality pattern transfer.

Technology

The inventors use an electrostatic actuator (i.e. parallel plate capacitor) to modify the pressure distribution at the contact interface between elastomeric microcontact printing stamps and corresponding substrates. A gap is formed between two electrodes using patterned features in the elastomeric stamp. Conductive electrodes are placed against a rigid backing and the elastomeric stamp pattern. Energizing the electrodes will create an attractive force that causes the elastomeric features to deform much as they would at a printing interface. This will result in actuator behavior characterized by the actuator force and the stiffness of the stamp features.

Closed loop feedback control is achieved using electrostatic actuators for local stamp control and optical sensing to determine the feedback variable. This control variable can be used to calculate controller error, which determines the dynamic behavior of the controller and actuator signals. The independent local pressure zones can be used to control contact behavior, for example along the contact interface between a printing roller and impression roller.

Advantages 

  • Control and measure stamp pressure distribution to avoid deformations
  • Smaller gap in parallel plate capacitor and more sensitive actuator/sensor
  • New control paradigm allows for multiple actuation methods to provide accuracy and dimensional stability