Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

A technique for preparing semiconductor cross sections for both TEM and SEM analysis

1989 ◽  
Vol 47 ◽  
pp. 712-713
Author(s):  
Stanley J. Klepeis ◽  
J.P. Benedict ◽  
R.M Anderson
Keyword(s):  
Sample Preparation ◽  
Cross Section ◽  
Cross Sections ◽  
Sem Analysis ◽  
Preparation Technique ◽  
Ion Milling ◽  
Tem Analysis ◽  
Polished Cross Section ◽  
Area Of Interest ◽  
Polished Side

The ability to prepare a cross-section of a specific semiconductor structure for both SEM and TEM analysis is vital in characterizing the smaller, more complex devices that are now being designed and manufactured. In the past, a unique sample was prepared for either SEM or TEM analysis of a structure. In choosing to do SEM, valuable and unique information was lost to TEM analysis. An alternative, the SEM examination of thinned TEM samples, was frequently made difficult by topographical artifacts introduced by mechanical polishing and lengthy ion-milling. Thus, the need to produce a TEM sample from a unique,cross-sectioned SEM sample has produced this sample preparation technique.The technique is divided into an SEM and a TEM sample preparation phase. The first four steps in the SEM phase: bulk reduction, cleaning, gluing and trimming produces a reinforced sample with the area of interest in the center of the sample. This sample is then mounted on a special SEM stud. The stud is inserted into an L-shaped holder and this holder is attached to the Klepeis polisher (see figs. 1 and 2). An SEM cross-section of the sample is then prepared by mechanically polishing the sample to the area of interest using the Klepeis polisher. The polished cross-section is cleaned and the SEM stud with the attached sample, is removed from the L-shaped holder. The stud is then inserted into the ion-miller and the sample is briefly milled (less than 2 minutes) on the polished side. The sample on the stud may then be carbon coated and placed in the SEM for analysis.

Comparison of ultra high resolution immersion lens CFESEM and TEM for imaging of semiconductor devices

1990 ◽  
Vol 48 (4) ◽  
pp. 622-623
Author(s):  
Terrence Reilly ◽  
Al Pelillo ◽  
Barbara Miner
Keyword(s):  
High Resolution ◽  
Sample Preparation ◽  
Cross Sections ◽  
Semiconductor Devices ◽  
Ion Milling ◽  
Observation Area ◽  
Transmission Electron ◽  
Milling Machines ◽  
Resolution Imaging ◽  
Electron Microscopes

The use of transmission electron microscopes (TEM) has proven to be very valuable in the observation of semiconductor devices. The need for high resolution imaging becomes more important as the devices become smaller and more complex. However, the sample preparation for TEM observation of semiconductor devices have generally proven to be complex and time consuming. The use of ion milling machines usually require a certain degree of expertise and allow a very limited viewing area. Recently, the use of an ultra high resolution "immersion lens" cold cathode field emission scanning electron microscope (CFESEM) has proven to be very useful in the observation of semiconductor devices. Particularly at low accelerating voltages where compositional contrast is increased. The Hitachi S-900 has provided comparable resolution to a 300kV TEM on semiconductor cross sections. Using the CFESEM to supplement work currently being done with high voltage TEMs provides many advantages: sample preparation time is greatly reduced and the observation area has also been increased to 7mm. The larger viewing area provides the operator a much greater area to search for a particular feature of interest. More samples can be imaged on the CFESEM, leaving the TEM for analyses requiring diffraction work and/or detecting the nature of the crystallinity.

A procedure for cross-sectioning materials for TEM analysis without ion milling

1990 ◽  
Vol 48 (4) ◽  
pp. 742-743
Author(s):  
J.P. Benedict ◽  
Ron Anderson ◽  
S. J. Klepeis
Keyword(s):  
Surface Topography ◽  
Milling Time ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Cleaning Operation ◽  
Tem Analysis ◽  
Platinum Silicide ◽  
Surface Alteration ◽  
Polishing Damage ◽  
Tools And Methods

Traditional specimen preparation procedures for non-biological samples, especially cross section preparation procedures, involves subjecting the specimen to ion milling for times ranging from minutes to tens of hours. Long ion milling time produces surface alteration, atomic number and rough-surface topography artifacts, and high temperatures. The introduction of new tools and methods in this laboratory improved our ability to mechanically thin specimens to a point where ion milling time was reduced to one to ten minutes. Very short ion milling times meant that ion milling was more of a cleaning operation than a thinning operation. The preferential thinning and the surface topography that still existed in briefly ion milled samples made the study of interfaces between materials such as platinum silicide and silicon difficult. These two problems can be eliminated by completely eliminating the ion milling step and mechanically polishing the sample to TEM transparency with the procedure outlined in this communication. Previous successful efforts leading to mechanically thinned specimens have shown that problems center on tool tilt control, removal of polishing damage, and specimen cleanliness.

Scanning Electron Microscopic and Electrophoretic Observations on Barium Sulphate Used to Adsorb Clotting Factors

1975 ◽  
Vol 33 (02) ◽  
pp. 256-270
Author(s):  
R. M Howell ◽  
S. L. M Deacon
Keyword(s):  
Electron Microscopy ◽  
Factor Xa ◽  
Barium Sulphate ◽  
High Density ◽  
Low Density ◽  
Factor X ◽  
Clotting Factors ◽  
Electron Microscopic ◽  
Complementary Techniques ◽  
Scanning Electron

SummaryElectron microscopy and particle electrophoresis were found to be complementary techniques with which to complete the physical data from an earlier study on barium sulphates used to adsorb clotting factors from serum. The differences revealed by scanning electron microscopy (S. E. M.) in the physical shape of low and high density grades of barium sulphate particles appear to be of greater significance than charge as expressed by electrophoretic mobility, in determining whether or not precursor or preformed factor Xa is eluted.This conclusion was based on the finding that at pH values close to 7, where the adsorption from serum occurs, all samples with the exception of natural barytes were uncharged. However as the high-density, or soil-grade, was found by S. E. M. to consist of large solid crystals it was suggested that this shape might induce activation of factor X as a result of partial denaturation and consequent unfolding of the adsorbed protein. In contrast, uptake of protein into the centre of the porous aggregates revealed by S. E. M. pictures of low-density or X-ray grade barium sulphate may afford protection against denaturation and exposure of the enzyme site.The porous nature of particles of low-density barium sulphate compared with the solid crystalline forms of other grades accounts not only for its lower bulk density but also for its greater surface/gram ratio which is reflected by an ability to adsorb more protein from serum.Neither technique produced evidence from any of the samples to indicate the presence of stabilising agents sometimes used to coat particles in barium meals.

The basis of quality of sheep pelts and fur products is morphological features of the skin of sheep

2020 ◽  
pp. 50-57
Author(s):  
I. Dmitrik ◽  
G. Zavgorodnyaya
Keyword(s):  
Mechanical Strength ◽  
Breaking Load ◽  
Hair Follicles ◽  
Morphological Features ◽  
High Density ◽  
Fat Cells ◽  
High Quality ◽  
Histological Features ◽  
Weakened Zone

The morphological and histological features of the skin and wool cover of sheep as the basis for the quality of fur sheep pelts have been studied. The most important properties of sheep pelts (uniformity, thinness and density of wool) are provide the possibility of producing high-quality fur semi-finished products from them. However, the features of the histostructure of fine-wool sheep determine the low mechanical strength of the “facial” layer of skin. As a result, the “front” layer during processing often cracks to the upper border of the reticular layer or even peels off from the latter, making the sheep pelt unsuitable for use on fur products. These defects in fur practice are called “cracking” and “peeling” of the facial layer. They are mainly peculiar to sheep pelts of fine-wooled sheep. In these animals due to the high density and tone of the coat, the roots and hair follicles, root vaginas, secretory departments, excretory ducts of the glands and other structures occupy a significant share of the volume in the thickness of the Pilar layer (up to 25–30 %). The share of fibrous structures remains less volume, and these structures themselves are relatively weakly developed, located loosely and loosely intertwined with each other. The accumulations of fat cells that occur here also cannot be attributed to skin-strengthening elements. In fine-fleece sheep the pilar layer is on average 60 % of the thickness of the dermis. Therefore, more than half of its thickness is a weakened zone. The strength of the “front” layer is not the same in different fine-wool breeds of sheep and in different animals within the breed. For example, the average breaking load for cod of the “front” layer in Soviet Merino pelts is 1,25 kg, and in Precoce is 2,49 kg.

scholarly journals Low-Temperature Mechanical Properties of High-Density and Low-Density Polyethylene and Their Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1821
Author(s):  
Ildar I. Salakhov ◽  
Nadim M. Shaidullin ◽  
Anatoly E. Chalykh ◽  
Mikhail A. Matsko ◽  
Alexey V. Shapagin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Impact Strength ◽  
Relative Elongation ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Elongation At Break ◽  
Subzero Temperatures ◽  
Izod Impact

Low-temperature properties of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and their blends were studied. The analyzed low-temperature mechanical properties involve the deformation resistance and impact strength characteristics. HDPE is a bimodal ethylene/1-hexene copolymer; LDPE is a branched ethylene homopolymer containing short-chain branches of different length; LLDPE is a binary ethylene/1-butene copolymer and an ethylene/1-butene/1-hexene terpolymer. The samples of copolymers and their blends were studied by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), 13С NMR spectroscopy, and dynamic mechanical analysis (DMA) using testing machines equipped with a cryochamber. It is proposed that such parameters as “relative elongation at break at −45 °C” and “Izod impact strength at −40 °C” are used instead of the ductile-to-brittle transition temperature to assess frost resistance properties because these parameters are more sensitive to deformation and impact at subzero temperatures for HDPE. LLDPE is shown to exhibit higher relative elongation at break at −45 °C and Izod impact strength at −20 ÷ 60 °C compared to those of LDPE. LLDPE terpolymer added to HDPE (at a content ≥ 25 wt.%) simultaneously increases flow properties and improves tensile properties of the blend at −45 °C. Changes in low-temperature properties as a function of molecular weight, MWD, crystallinity, and branch content were determined for HDPE, LLDPE, and their blends. The DMA data prove the resulting dependences. The reported findings allow one to understand and predict mechanical properties in the HDPE–LLDPE systems at subzero temperatures.

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