Weekly Journal Club

June 30, 1995

From:  Weldon.Cordell.Knighton@Dartmouth.EDU (Weldon Cordell Knighton)

Title:  SEMATECH Minienvironment Benchmarking Project
Journal:   Journal of the IES (Institute of Environmental Sciences).  
May/June 1995, PAGES:  36-42

SEMATECH did an experiment comparing clean labs to minienvironment facilities. The test was extensive and covered many factors including air velocity and aerosol tests. It was found that silicon wafers left in the minienvironment were approximately 1,000 times cleaner than those wafers just left in the class-1 lab itself.

From:   Jennifer.Frida.Kaira@Dartmouth.EDU (Jennifer Frida Kaira)

Title: Micromachining technology and biomedical engineering.
Author: Fujimasa, I
Journal: Applied biochemistry and biotechnology, 1993 Mar;38(3):233-42.
date:930300

The article discusses micromachining techniques as applied to microsurgery, fiberscopic operation, micromanipulation, artificial organ implant and drug delivery. Some of the micromachines used include microactuators and sensors. The emphasis is to create components able to work on the structure and functions of systems, cells, and other units far smaller than bodily organs.

From:  Joshua.Albert.Logan@Dartmouth.EDU (Joshua Albert Logan)

Title:  "Developing new miniature energy systems".  
Authors:  Wegeng, Robert S. and M. Kevin Drost.
Journal:  MECHANICAL ENGINEERING,
September, 1994 (vol. 116, no. 9).  
pp.  82-5.

Staff engineers at Pacific Northwest Laboratory in Richland, Washington, are applying the microtechnological craze to energy systems, designing and testing the improved efficiency of miniature heat pumps and heat engines.

From: Carla.N.Shelton@dartvax.dartmouth.edu  Mon Jul  3 10:45:37 1995

Title: Optical circular sampling system for translation and rotoation invariant
pattern recognition.
Author: Daniel Asselin, Henry-H. Arsenault, Donald Prevost
Journal:  Optics Communications
vol. 110  n 5-6 Sept 1, 1994 pp.507-513

Comments: This article discussed the use of computer-generated holograms in optical pattern recognition of two-dimensional objects. It also discussed the use of the wedge ring dectector as a method used to achieve rotation invariant variable recognition

From: Simone.M.Ferdinand@Dartmouth.EDU (Simone M. Ferdinand)

Title: A Micromachined Silicon Sieve Electrode for Nerve Regeneration
Applications
Authors: Tayfun Akin, Khalil Najafi, Richard H. Smoke, and Robert M. Bradley
Journal: IEEE Transactions on Biomedical Engineering
Volume: 41 No. 4, April 1994, Pages: 305-313

The article describes the microfabrication and testing of a silicon electrode for use in nerve regeneration applications. The electrode contains a thin diaphragm with various size through-holes which allow regeneration of individual axons of varying diameters. Recording/stimulating sites surround the holes and allow long-term recording and stimulation of axons. The fabrication-process is single-sided, requires five masks, and is compatible with integrated multilead silicon ribbon clabes for CMOS circuit compatibility.

 From: Nicholas.C.Fuller@Dartmouth.EDU (Nicholas C. Fuller)
 
Title:  "Micromachined Detectors for an enzyme-based F.I.A." 
Journal:  Journal Of Biochemistry and Biotechnology, 1993, volume 41.  
Authors:  M. Suda, T.  Sakuhara, Y. Murakami and I. Karube.  

This article was entitled "Micromachined Detectors for an enzyme-based F.I.A." by four Japanese scientists M. Suda, T. Sakuhara, Y. Murakami and I. Karube. This article was about the use of micromachining technology in the fabrication of Biosensors. In partciular the article discussed the development of an electrochemcial flow cell used in liquid chromatography(flow injection analysis) intoa biosensor. This was achieve by attaching an enzyme immobilised column to the flow cell. This column was made by anisotropically etching silicon and served to fix the position of the enzyme, such that, when the particular subsrtae (such as glucose) was injected into the column the enzyme would reduce the molecular structure to an ionic one making the substrate conductive in aqueous solution. The substrate was consequently detected by the microcurrent it produced in solution. For future processes, the substrate injector and plunge pump would be manufactured using micromachinig techniques. This article was found under medline using micromach as a search word.

From: Zahid.Maqsud@Dartmouth.EDU (Zahid Maqsud)
Title:  Flexible, Dry-Released Process for Aluminum Electrostatic Actuators 
Autohrs:   Christopher W. Storment, David A. Borkholder, Victor Westerlind, 
           John W. Suh, Nadim I. Maluf, Gregory T. A.  Kovacs. 
Source:  Journal of Microelectromechanical Systems, Vol 3, No. 3, September 1994

July 7, 1995

From: Jennifer.Frida.Kaira@Dartmouth.EDU (Jennifer Frida Kaira)
Title: Fabrication and evaluation of flexible microgipper
Author: Suzuki, Yoshihiko
Source:Japanese Journal of Applied Physics
		part 1: Regular Papers & Short Notes & 	    
		Review Papers 33 4A April 1994. 
		p 2107-2112

This paper proposes a new type of flexible microgripper (FMG) which is electrothermally and electromagnetically driven and has low driving voltage. It presents design, theortical consideration, fabrication and finger characteristics. In order to confirm their method, the paper demonstrates the capability of the flexible finger motion of the FMG.

From: Simone M. Ferdinand   (co-presented with Weldon Knighton)
Title: A Method to Etch Undoped Silicon Cantilever Beams
Authors: Wai-shing Choi, Jan G. Smits
Publication: Journal of Microelectromechanical Systems, Vol. 2., No. 2., Pages
82-86.
Date: June 1993

The article outlines a method of fabricating silicon cantilever beams oriented in the <100> direction by etching (100) silicon wafers. The scheme uses two masks. Anisotropic etching is performed in sodium hydroxide to produce cantilevers with background doping concentration levels and vertical edges. This method is presented as an alternative to those which use back-etching, heavily doped boron etch stops, or anodic oxidation etch stops.

From: Nicholas.C.Fuller@Dartmouth.EDU (Nicholas C. Fuller)
Title:    Evaluation of an ingestible telemetric temperature sensor 
          for deep hyperthermia application
Source:   International Journal of Radiation,
          Oncology, Biology, and Physics

My most recent article came from the International Journal of Radiation, Oncology, Biology, and Physics entitled "Evaluation of an ingestible telemetric temperature sensor for deep hyperthermia applications". This article discussed the use of a temperature sensitive quartz crystal to monitor temperatures in regions of the body where heat is being applied to treat tumors. The device known as a radio pill is 2cm in length and icm in diameter and as such is unable to treat areas where it would have to pass through the blood stream. The functioning of the device can be deduced from its nomenclature. The device contains a temperature sensitive crystal which is coupled to an inductor. This circuit, powered by a siver oxide battery, functions like a L.R.C. circuit producing radio waves as it oscillates. The output signal is detected by a receiver outside of the body. Several factors, such as, elctrmagnetic interference, ionizing radiation doses were studied to test the efficiency of the crystal. Future work for the device would be centered around the decreasing the size of the device and on improving the accuracy of its results which, up to that time, fell below theH.P.C.'s alllowed experimental error 0.2%. Nick

From: Zahid.Maqsud@Dartmouth.EDU (Zahid Maqsud)
Title:  A Computer-Aided Design System for 
        Microelectromechanical Systems (MEMCAD) 
Authors:   Stephen D. Senturia, Robert M. Harris, Brian P. Johnson, 
           Songmin Kim, Kieth Nabors, Matthew A.  Shulman, Jacob K. White. 
Source:  Journal of Microelectromechanical Systems, Vol 1, No. 1, March 1992.

From: Carla.N.Shelton@Dartmouth.EDU (Carla N. Shelton)
Title: Metallic Microstructures  Fabricated Using Photosensitive Polyimide
       Electroplating molds
Authors:  A. Bruno Frazier and Mark G. Allen, member, IEEE
Source:  Journal of Microelectromechanical systems, Vol 2, No 2, June 1993

Comments: This article discusses the use of photosensitive polyimide electroplating molds in the fabrication of metallic microstructures (eg. microactuators or micromotors)
This article outlines the basic process which illuminates the advantages of using Photosensitve polyimide electroplaing molds in comparison with the LIGA process. I chose this particular article because it outlines a process similar to the one we are using in our exploration of micromachine technology.

From: Joshua Albert Logan
Author:  O'Conner, Leo.
Title:  "Miniature motors for future PCs".
Source:  MECHANICAL ENGINEERING, February, 1995 
(vol. 116, no. 9).  pp.  63-65.

Engineers at the University of California (Los Angeles) and the California Institute of Technology (Pasadena) have developed and are fine-tuning a micromotor that is to be added to the read-write head of future personal computers. This device, which moves the head through a range of 20 microns above the data disk, is capable of vastly increasing the information capacity of modern magnetic data storage systems.

From: Makishma.M.Cabo@Dartmouth.EDU (Makishma M. Cabo)
Authors:  Mahesh Uttamlal and David R. Walt
Title:  " A Fiber-Optic Carbon Dioxide Sensor for Fermentation Monitoring"
Source:

This fiber-optic chemical sensor was developed for determining dissolved carbon dioxide and assessing its performance for on-line monitoring of fermentation. The sensor operates on the Severinghaus pCO2 electrode principle; it consists of a pH sensitive dye in an HCO3- buffer solution entrapped in an expanded PTFE support head at the distal end of an optical fiber by a gas permeable membrane. CO2 crossing the membrane produces a pH change in the indicator solution.

On-line monitoring is important, not only for control strategies but for providing a greater insight into the dynamics of the bio-reactions that regulate production.

This paper was insightful in displaying a simple and inexpensive sensor that can be used economically in the fermentation process.

From: Weldon.Cordell.Knighton@Dartmouth.EDU (Weldon Cordell Knighton)AND
From: Carla.N.Shelton@dartvax.dartmouth.edu  Mon Jul  3 10:45:37 1995
Title:  Effects of <110> oriented corner compensation structures on membrane
quality and convex corner integrity in <100> silicon using aqueous KOH.
Authors: R.P. van Kampen and R.F. Wolffenbuttel

This article was about the adding of compensation structures in an effort to preserve the shape of convex corners when using a KOH etch. Experiments showed that the <411> plane was responsible for the under-etching of these structures and that a clean top to bottom compensation structure is not possible. The compensation structures used were in the <100> and <110> directions. It is also shown that the compensation structures leave ridges on the wanted structure which can not be removed with further etching.

July 14, 1995

• From: Simone.M.Ferdinand@Dartmouth.EDU (Simone M. Ferdinand) Title: Silicon sensors with integral tips for atomic force microscopy: a novel single-mask fabrication Authors: M M Farooqui and A G R Evans University of Southampton, Southampton SO9 5NH, UK Journal: Journal of Micromechanics and Microengineering Stuctures, Devices and Systems Location: Vol. 3, No.1, March 1993, Pgs 8-12 Content: The paper describes a single-mask process for fabrication of silicon microcantilevers with integral silicon tips for use in atomic force microscopy (AFM). The tips have radii of a few nanometers. The process eliminates alignment errors introduced while using more than one mask so that the silicon tips are located precisely on the central axis of the cantilevers. The central location of the tip prevents twisting of the cantilever and distortion of topographic images while performing microscopy using reflected laser beam technology.

   From: Jennifer.Frida.Kaira@Dartmouth.EDU (Jennifer Frida Kaira)
  Title: Fabrication and testing of a microdynamic rotor for blood flow
   measurements.
  Source: Micromech. Microeng. 1(1991)60-65
  Authors: Rapoport, Reed and Weiss
  

  Abstract: The purpose was to design and fabricate an in vivo flow sensor to measure blood velocity in coronary arteries( to determine Angiopasty). A three-silicon-layer process, in which the the rotor turns between the substrate and a semicircular cap, was developed to fabricate the microdynamic device. Repeatable rotation rates in flowing fluids were obtained, and qualitative observations concerning operation of the device in blood were noted. The article also proposed the use of a magnetoresistive sensing element as a non-contacting coupling technique.

July 21

• From: Simone.M.Ferdinand@Dartmouth.EDU (Simone M. Ferdinand) Title: Application of porous silicon as a sacrificial layer Journal: Sensors and Actuators A, 43 (1994) Pgs. 239-242 Authors: W. Lang, P. Steiner, A. Richter, K. Marusczyk, G. Weinmann and G. Sandmaier Content: Free standing structures can be realized using anisotropic etching in KOH, surface micromaching sacrificial layer (silicon oxide) methods, or porous silicon technology. The article describes how porous silicon can be used as a sacrificial layer in surface micromaching processes to produce large distances (= 100 $B5m) from the structure to the substrate. The application of this process for making free standing polysilicon bridges and flow channels in doped p-silicon wafers is described.

  From: Makishma.M.Cabo@Dartmouth.EDU (Makishma M. Cabo)
  Authors: Chih-Hu Ho and Vladimir Hlady
  Title: "Fluorescence assay for measuring lipid deposits on contact lens surfaces"
  Source:
  

  A simple fluorescence assay was developed for estimating the propensity of a contact lens surface towards the uptake of lipids and formation of lipid deposits. The assay is based on the incubation of the contact lenses with an artifical tear-lipid mixture, staining of the lenses with a fluorescent lipid probe, Nile Red, and subsequent macroscopic imaging fluorescent lipid deposits on the contact lens surface with a thermoelectrically cooled charge-coupled device (CCD) camera.

  This new method of estimating the sorption of lipids is perhaps a more economical way of preventing spoilation on contact lenses. Due to the advent of "soft" contact lenses, spoilation has become the major ocular compatibility problem due to extended wear capabilities of the lenses. The fluorescence assay is a way to detect the presence of lipid deposition before too much ocular damage is done.

July 28

August 4

August 11