Indentation Testing of Thin Films and Hard Materials

Precision structured polymer thin films with microstructures comparable to or greater than the film thickness are highly desired in many applications. Such micro-patterned thin films, however, are difficult to fabricate using the standard hot embossing technology where both halves of the mold are made of hard materials. This study investigated a rubber-assisted embossing process for structuring thin polymer films. The advantages of the rubber backup instead of a hard support include but are not limited to 1) simplifying the embossing tool, 2) protecting the embossing master, 3) facilitating embossing pressure buildup, and 4) accommodating conformal forming of microscale shell patterns. Several design and process variables including rubber hardness, embossing temperature, embossing pressure and holding time were carefully studied. Thin polystyrene films in a thickness of 25 μm were accurately patterned with microgrooves of characteristic dimensions on the order of 100 μm.

Download Full-text

Surface and Shape Deposition Manufacturing for the Fabrication of a Curved Surface Gripper

Journal of Mechanisms and Robotics ◽

10.1115/1.4029492 ◽

2015 ◽

Vol 7 (2) ◽

Cited By ~ 22

Author(s):

Srinivasan A. Suresh ◽

David L. Christensen ◽

Elliot W. Hawkes ◽

Mark Cutkosky

Keyword(s):

Thin Films ◽

Laser Cutting ◽

Biological Systems ◽

Robotic Systems ◽

Curved Surfaces ◽

Structural Elements ◽

Hard Materials ◽

Subtractive Manufacturing ◽

Multiple Materials ◽

Shape Deposition Manufacturing

Biological systems such as the gecko are complex, involving a wide variety of materials and length scales. Bio-inspired robotic systems seek to emulate this complexity, leading to manufacturing challenges. A new design for a membrane-based gripper for curved surfaces requires the inclusion of microscale features, macroscale structural elements, electrically patterned thin films, and both soft and hard materials. Surface and shape deposition manufacturing (S2DM) is introduced as a process that can create parts with multiple materials, as well as integrated thin films and microtextures. It combines SDM techniques, laser cutting and patterning, and a new texturing technique, surface microsculpting. The process allows for precise registration of sequential additive/subtractive manufacturing steps. S2DM is demonstrated with the manufacture of a gripper that picks up common objects using a gecko-inspired adhesive. The process can be extended to other integrated robotic components that benefit from the integration of textures, thin films, and multiple materials.

Download Full-text

Evaluation of Endurance Characterizations of Ceramic Thin Films Deposited on the Cemented Carbide Substrate by Cyclic Sphere Indentation Testing

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.78.1423 ◽

2012 ◽

Vol 78 (794) ◽

pp. 1423-1431 ◽

Cited By ~ 2

Author(s):

Thoru TAKAMATSU ◽

Hirotaka TANABE ◽

Yuui IZUMI ◽

Shigeki HORII

Keyword(s):

Thin Films ◽

Cemented Carbide ◽

Indentation Testing ◽

Ceramic Thin Films

Download Full-text

Practical limitations to indentation testing of thin films

10.2172/663560 ◽

1998 ◽

Author(s):

J.A. Schneider ◽

K.F. McCarty ◽

J.R. Heffelfinger ◽

N.R. Moody

Keyword(s):

Thin Films ◽

Indentation Testing

Download Full-text

A parametric elastic model for indentation testing of thin films

Journal of Physics D Applied Physics ◽

10.1088/0022-3727/26/12/005 ◽

1993 ◽

Vol 26 (12) ◽

pp. 2123-2131 ◽

Cited By ~ 29

Author(s):

J A Ogilvy

Keyword(s):

Thin Films ◽

Elastic Model ◽

Indentation Testing

Download Full-text

Measurement of Thin Film Mechanical Properties Using Nanoindentation

MRS Bulletin ◽

10.1557/s0883769400041634 ◽

1992 ◽

Vol 17 (7) ◽

pp. 28-33 ◽

Cited By ~ 568

Author(s):

G.M. Pharr ◽

W.C. Oliver

Keyword(s):

Thin Film ◽

Thin Films ◽

Mechanical Properties ◽

Hard Coatings ◽

Optical Coatings ◽

Small Scale ◽

Nanometer Scale ◽

Indentation Testing ◽

Microelectronic Device ◽

Convenient Means

One of the simplest ways to measure the mechanical properties of a thin film is to deform it on a very small scale. Because indentation testing with a sharp indenter is one convenient means to accomplish this, nanoindentation, or indentation testing at the nanometer scale, has become one of the most widely used techniques for measuring the mechanical properties of thin films. Other reasons for the popularity of nanoindentation stem from the ease with which a wide variety of mechanical properties can be measured without removing the film from its substrate and the ability to probe a surface at numerous points and spatially map its mechanical properties. The utility of the mapping capability is illustrated in Figure 1, which shows several small indentations made at selected points in a microelectronic device. The hardness and modulus of the device were determined at each point. In addition to microelectronics, nanoindentation has also proved useful in the study of optical coatings, hard coatings, and materials with surfaces modified by ion implantation and laser treatment.

Download Full-text

Practical Limitations to Indentation Testing of Thin Films

MRS Proceedings ◽

10.1557/proc-505-91 ◽

1997 ◽

Vol 505 ◽

Author(s):

J. A. Schneider ◽

K. F. McCarty ◽

J. R. Heffelfinger ◽

N. R. Moody

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

Scanning Force Microscopy ◽

Indentation Testing ◽

Force Microscopy ◽

Sapphire Substrates ◽

Low Load ◽

Scanning Force ◽

Deposited Films

ABSTRACTA method that is becoming increasingly common for measuring the mechanical behavior of thin films is low-load indentation testing. However, there can be complications in interpreting the results as many factors can affect hardness and moduli measurements such as surface roughness and determination of the indentation contact area. To further our understanding, the mechanical properties of thin (50 nm) films of AlN on sapphire substrates were evaluated using a scanning force microscopy (SFM) based pico-indentation device to allow imaging of the surface and indentations. Our primary emphasis was the types of problems or limitations involved in testing very thin, as deposited films in which properties are desired over indentation depths less than 50 nm.

Download Full-text

The Small Angle Cleavage Technique for XTEM Sample Preparation

Microscopy and Microanalysis ◽

10.1017/s1431927600024454 ◽

1998 ◽

Vol 4 (S2) ◽

pp. 866-867

Author(s):

S. D. Walck ◽

J. P. McCaffrey

Keyword(s):

Thin Films ◽

Silicon Carbide ◽

Sample Preparation ◽

Small Angle ◽

Substrate Material ◽

Semiconductor Materials ◽

Inexpensive Method ◽

Cross Sectional ◽

Hard Materials ◽

Typical Material

The Small Angle Cleavage Technique (SACT) is a relatively simple and inexpensive method of producing superior cross sectional TEM specimens. For speed of preparation, it is unsurpassed; for example, ten samples can easily be prepared in about an hour from a typical material. It is particularly well suited for rapidly examining coatings and thin films very soon after they have been deposited. A major limitation of the technique is that it does require the substrate material to cleave or fracture. For this reason, it has been applied almost exclusively to semiconductor materials, but the technique has been extended quite successfully to other substrates such as glass, silicon carbide, quartz, sapphire, and other hard materials. Several procedures have been added or modified to the original technique developed by McCaffrey that makes it much easier to get started in using the technique. A detailed pictorial outline of the technique has been described elsewhere by the authors.

Download Full-text

The Small Angle Cleavage Technique: An Update

MRS Proceedings ◽

10.1557/proc-480-149 ◽

1997 ◽

Vol 480 ◽

Cited By ~ 15

Author(s):

Scott D. Walck ◽

John P. McCaffrey

Keyword(s):

Thin Films ◽

Silicon Carbide ◽

Small Angle ◽

Substrate Material ◽

Semiconductor Materials ◽

Angular Range ◽

Inexpensive Method ◽

Cross Sectional ◽

Hard Materials ◽

Original Technique

AbstractThe Small Angle Cleavage Technique is a relatively simple and inexpensive method of producing superior cross sectional TEM specimens. For speed of preparation, it is unsurpassed. One limitation is that the technique does require the substrate material to cleave or fracture. For this reason, it has been applied almost exclusively to semiconductor materials. Recently, the technique has been extended to other substrates such as glass, silicon carbide, quartz, sapphire, and other hard materials. It is particularly well suited for rapidly examining coatings and thin films very soon after they are deposited. Several procedures have been added or modified to the original technique developed by McCaffrey to simplify the technique. The steps are presented in a detailed pictorial outline form. A method for mounting the cleaved samples utilizing a commercially available grid is presented. In addition, the advantages that the special geometry of the prepared samples have when mounted properly in a double-tilt holder are discussed with respect to the angular range of tilting experiments that are now possible in the TEM.

Download Full-text