In-process monitoring of shape accuracy of flat surfaces of optical and microelectronic components in polishing

2017 ◽  
Vol 39 (4) ◽  
pp. 282-287 ◽  
Author(s):  
Yu. D. Filatov ◽  
V. I. Sidorko ◽  
S. V. Kovalev ◽  
O. Yu. Filativ ◽  
G. Monteil
2020 ◽  
Vol 299 ◽  
pp. 311-315
Author(s):  
Dmitry Kruchinin ◽  
Liana Garayshina ◽  
Elena Farafontova

The problematic issues connected with the optical details deformations that arise during the temperature tests of cemented assemblies are considered. Climatic tests of optical devices after assembly result in a change of technical product characteristics. The research problem is to define how N and ∆N of surfaces of cemented optical assemblies are changing after the temperature testing. The research objects are plane convex lenses fabricated of LK7 (LZOS) glass brand and plane concave lenses - of TF7 (LZOS). Before cementing, the bounded surfaces cleaning by the hydromechanical method in the clean room has been purged. The temperature testing of samples is held at 22, 50 and 65 °C. The effect of temperature on a surface deformation of cemented optical assemblies is experimentally established. The comparison of effect of optical cements OK72FT5 and OK72FT15 on the optical surfaces deformation is carried out. In this paper we have compared the results of shape accuracy of the external surfaces of optical assemblies and the flat surfaces. Interferograms of lenses after heat treatment of optical assemblies are presented. It is determined that the cement polymerization temperature equals or higher than the test temperature.


Author(s):  
M. H. Rhee ◽  
W. A. Coghlan

Silicon is believed to be an almost perfectly brittle material with cleavage occurring on {111} planes. In such a material at room temperature cleavage is expected to occur prior to any dislocation nucleation. This behavior suggests that cleavage fracture may be used to produce usable flat surfaces. Attempts to show this have failed. Such fractures produced in semiconductor silicon tend to occur on planes of variable orientation resulting in surfaces with a poor surface finish. In order to learn more about the mechanisms involved in fracture of silicon we began a HREM study of hardness indent induced fractures in thin samples of oxidized silicon.Samples of single crystal silicon were oxidized in air for 100 hours at 1000°C. Two pieces of this material were glued together and 500 μm thick cross-section samples were cut from the combined piece. The cross-section samples were indented using a Vicker's microhardness tester to produce cracks. The cracks in the samples were preserved by thinning from the back side using a combination of mechanical grinding and ion milling.


Author(s):  
J. A. Panitz

Tunneling is a ubiquitous phenomenon. Alpha particle disintegration, the Stark effect, superconductivity in thin films, field-emission, and field-ionization are examples of electron tunneling phenomena. In the scanning tunneling microscope (STM) electron tunneling is used as an imaging modality. STM images of flat surfaces show structure at the atomic level. However, STM images of large biological species deposited onto flat surfaces are disappointing. For example, unstained virus particles imaged in the STM do not resemble their TEM counterparts.It is not clear how an STM image of a biological species is formed. Most biological species are large compared to the nominal electrode separation of ∼ 1nm that is required for electron tunneling. To form an image of a biological species, the tunneling electrodes must be separated by a distance that would normally be too large for a tunneling current to be observed.


Author(s):  
M. Gajdardziska-Josifovska ◽  
B. G. Frost ◽  
E. Völkl ◽  
L. F. Allard

Polar surfaces are those crystallographic faces of ionically bonded solids which, when bulk terminated, have excess surface charge and a non-zero dipole moment perpendicular to the surface. In the case of crystals with a rock salt structure, {111} faces are the exemplary polar surfaces. It is commonly believed that such polar surfaces facet into neutral crystallographic planes to minimize their surface energy. This assumption is based on the seminal work of Henrich which has shown faceting of the MgO(111) surface into {100} planes giving rise to three sided pyramids that have been observed by scanning electron microscopy. These surfaces had been prepared by mechanical polishing and phosphoric acid etching, followed by Ar+ sputtering and 1400 K annealing in ultra-high vacuum (UHV). More recent reflection electron microscopy studies of MgO(111) surfaces, annealed in the presence of oxygen at higher temperatures, have revealed relatively flat surfaces stabilized by an oxygen rich reconstruction. In this work we employ a combination of optical microscopy, transmission electron microscopy, and electron holography to further study the issue of surface faceting.


Author(s):  
Lee H. Veneklasen

This paper discusses some of the unique aspects of a spectroscopic emission microscope now being tested in Clausthal. The instrument is designed for the direct parallel imaging of both elastic and inelastic electrons from flat surfaces. Elastic contrast modes of the familiar LEEM include large and small angle LEED, mirror microscopy, backscatter diffraction contrast (for imaging of surface structure), and phase contrast (for imaging of step dynamics)(1). Inelastic modes include topology sensitive secondary, and work function sensitive photoemission. Most important, the new instrument will also allow analytical imaging using characteristic Auger or soft X-ray emissions. The basic instrument has been described by Bauer and Telieps (2). This configuration has been redesigned to include an airlock, and a LaB6 gun, triple condensor lens, magnetic objective lens, a double focussing separator field, an imaging energy analyzer, and a real time image processor.Fig. 1 shows the new configuration. The basic beam voltage supply Vo = 20 KV, upon which separate supplies for the gun Vg, specimen Vs, lens electrode Vf, and analyzer bias Vb float. The incident energy at the sample can be varied from Vs = 0-1 KV for elastic imaging, or from Vg + Vs = (3 + Vs) KV for inelastic imaging. The image energy window Vs±V/2 may be varied without readjusting either the illumation, or imaging/analyzer optics. The diagram shows conjugate diffraction and image planes. The apertures defining incoming Humiliation and outgoing image angles are placed below the separator magnet to allow for their independent optimization. The instrument can illuminate and image 0.5-100 μm fields at 0-1 keV emission energies with an energy window down to 0.2 eV.


Author(s):  
Anand Tharanathan ◽  
Jason Laberge ◽  
Peter Bullemer ◽  
Dal Vernon Reising ◽  
Rich McLain

1998 ◽  
Vol 49 (9) ◽  
pp. 976-985
Author(s):  
M Wood ◽  
N Capon ◽  
and M Kaye

2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.


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