A novel sublimable mask lift-off method for patterning thin films

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 39-42).Photolithography's accuracy and scalability has made it the method for sub-micron-scale definition of single-crystal semiconductor devices for over half a century. Unfortunately, organic semiconductor devices are chemically incompatible with the types of resists, solvents, and etchants traditionally used. This work investigates the use of a chemically inert resist that relies on phase changes for lift-off patterning thin films of organic semiconductors and metals.by Matthias Erhard Bahlke.S.M

Alternative methods and materials for patterning organic thin film electronics

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.136Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 73-84).Photolithography's accuracy and scalability have made it the method for sub-micronscale definition of single-crystal semiconductor devices for over half a century. The ultimate goal for OLED manufacturing, however, is to replicate the widespread success of photoresist lithography without the use of the types of resists, solvents, and etchants traditionally used--organic small molecules are simply not compatible with these tools. Hence, there is motivation for a renewed examination of variants of this inherently parallel, high speed approach. This work investigates the use of chemically inert resists that rely on clearance mechanisms not found in traditional lithography. These primarily include employing phase changes for lift-off patterning thin films of organic semiconductors and metals, and also propose and discuss the use of combustible and magnetic materials.by Matthias Erhard Bahlke.Ph. D

Laboratory Thin-Film Encapsulation of Air-Sensitive Organic Semiconductor Devices

We present an approach, which is compatible with both glass and polymer substrates, to in-laboratory handling and intra-laboratory shipping of air-sensitive organic semiconductors. Encapsulation approaches are presented using polymer/ceramic and polymer/metal thin-film barriers using commercially available materials and generally available laboratory equipment. A technique for depositing an opaque vapor barrier, a transparent vapor barrier, and an approach to storing and shipping air-sensitive thin-film organic semiconductor devices on both polymer and glass substrates are presented. Barrier performance in air was tested using organic light-emitting diodes (OLEDs) as test devices. The half-life performance of OLEDs on plastic substrates in air exceeded 700 h, and that on glass exceeded 500 h. Commercially available heat-seal barrier bag systems for device shipping and storage in air were tested using a thin film of metallic calcium to test water permeation. More than four months of storage of a metallic calcium film in a heat-sealed foil bag was demonstrated in the best storage system. These approaches allow for the encapsulation of samples for longer duration testing and transportation than otherwise possible.United States. Air Force Office of Scientific Research (STTR FA9550-07-C-0056 under a subcontract with QD Vision, Inc.

Dry Lithography of Large-Area, Thin-Film Organic Semiconductors Using Frozen CO[subscript 2] Resists

To address the incompatibility of organic semiconductors with traditional photolithography, an inert, frozen CO[subscript 2] resist is demonstrated that forms an in situ shadow mask. Contact with a room-temperature micro-featured stamp is used to pattern the resist. After thin film deposition, the remaining CO[subscript 2] is sublimed to lift off unwanted material. Pixel densities of 325 pixels-per-inch are shown.United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0001088)MIT Energy Initiative (Graduate Fellowship in Energy