Lateral resolution improvement of laser-scanning imaging for nano defects detection

2014 ◽  
Vol 3 (4) ◽  
Author(s):  
Hiroki Yokozeki ◽  
Ryota Kudo ◽  
Satoru Takahashi ◽  
Kiyoshi Takamasu

AbstractDemand for higher efficiency in the semiconductor manufacturing industry is continually increasing. In particular, nano defects measurement on patterned or bare Si semiconductor wafer surfaces is an important quality control factor for realizing high productivity and reliability of semiconductor device fabrication. Optical methods and electron beam methods are conventionally used for the inspection of semiconductor wafers. Because they are nondestructive and suitable for high-throughput inspection, optical methods are preferable to electron beam methods such as scanning electron microscopy, transmission electron microscopy, and so on. However, optical methods generally have an essential disadvantage about lateral spatial resolution than electron beam methods, because of the diffraction limit depending on the optical wavelength. In this research, we aim to develop a novel laser-scanning imaging method that can be applied to nano-/micro manufacturing processes such as semiconductor wafer surface inspection to allow lateral spatial super-resolution imaging with resolution beyond the diffraction limit. In our proposed method, instead of detecting the light intensity value from the beam spot on the inspection surface, the light intensity distribution, which is formed with infinity corrected optical system, coming from the beam spot on the inspection surface is detected. In addition, nano scale shifts in the beam spot are applied for laser spot scanning using a conventional laser-scanning method in which the spots are shifted at about a 100 nm pitch. By detecting multiple light intensity distributions due to the nano scale shifts, a super-resolution image reconstruction with resolution beyond the diffraction limit can be expected. In order to verify the feasibility of the proposed method, several numerical simulations were carried out.

Author(s):  
Robley C. Williams ◽  
Harold W. Fisher

It has been previously shown that the electron beam as normally used in electron microscopy results in the destruction of molecules of untreated DNA1 and in the obliteration of the finer structures of tobacco mosaic virus embedded 9 in negative stain.We have developed methods whereby specimen damage by the electron beam is minimized by restricting irradiation of the region to be micrographed to that necessary for photographic exposure. Focusing and stigmatic correction are done on a selected specimen region nearby. In one method, applicable to a Siemens Elmiskop I, a minimal-size beam spot (∼2μ) is first placed near the edge of the viewing screen and visibje in the binocular.


2008 ◽  
Vol 16 (6) ◽  
pp. 3-5
Author(s):  
Stephen W. Carmichael

For the first few centuries of microscopy, spatial resolution was limited by the diffraction barrier. Recently, this barrier has been broken using several different methods. Optical methods that provide better resolution than the diffraction barrier are referred to as super-resolution. Although these techniques have significantly improved resolution in two dimensions (x and y) or in the axial dimension (z), it has not been possible to achieve substantial improvement in all three dimensions simultaneously. A study by Bo Huang, Wenqin Wang, Mark Bates, and Xiaowei Zhuang demonstrated a breakthrough by achieving a spatial resolution that is 10 times better than the diffraction limit in all three dimensions without using sample or optical-beam scanning.


2004 ◽  
Author(s):  
Tohru Satake ◽  
Nobuharu Noji ◽  
Takeshi Murakami ◽  
Manabu Tsujimura ◽  
Ichirota Nagahama ◽  
...  

BIOspektrum ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 380-382
Author(s):  
Sebastian Sputh ◽  
Sabine Panzer ◽  
Christian Stigloher ◽  
Ulrich Terpitz

AbstractThe diffraction limit of light confines fluorescence imaging of subcellular structures in fungi. Different super-resolution methods are available for the analysis of fungi that we briefly discuss. We exploit the filamentous fungus Fusarium fujikuroi expressing a YFP-labeled membrane protein showing the benefit of correlative light- and electron microscopy (CLEM), that combines structured illumination microscopy (SIM) and scanning election microscopy (SEM).


2005 ◽  
Author(s):  
Tohru Satake ◽  
Nobuharu Noji ◽  
Takeshi Murakami ◽  
Manabu Tsujimura ◽  
Ichirota Nagahama ◽  
...  

Author(s):  
G. G. Shaw

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.


Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).


Author(s):  
M. A. Hayat

Potassium permanganate has been successfully employed to study membranous structures such as endoplasmic reticulum, Golgi, plastids, plasma membrane and myelin sheath. Since KMnO4 is a strong oxidizing agent, deposition of manganese or its oxides account for some of the observed contrast in the lipoprotein membranes, but a good deal of it is due to the removal of background proteins either by dehydration agents or by volatalization under the electron beam. Tissues fixed with KMnO4 exhibit somewhat granular structure because of the deposition of large clusters of stain molecules. The gross arrangement of membranes can also be modified. Since the aim of a good fixation technique is to preserve satisfactorily the cell as a whole and not the best preservation of only a small part of it, a combination of a mixture of glutaraldehyde and acrolein to obtain general preservation and KMnO4 to enhance contrast was employed to fix plant embryos, green algae and fungi.


Author(s):  
T. Ichinokawa ◽  
H. Maeda

I. IntroductionThermionic electron gun with the Wehnelt grid is popularly used in the electron microscopy and electron beam micro-fabrication. It is well known that this gun could get the ideal brightness caluculated from the Lengumier and Richardson equations under the optimum condition. However, the design and ajustment to the optimum condition is not so easy. The gun has following properties with respect to the Wehnelt bias; (1) The maximum brightness is got only in the optimum bias. (2) In the larger bias than the optimum, the brightness decreases with increasing the bias voltage on account of the space charge effect. (3) In the smaller bias than the optimum, the brightness decreases with bias voltage on account of spreading of the cross over spot due to the aberrations of the electrostatic immersion lens.In the present experiment, a new type electron gun with the electrostatic and electromagnetic lens is designed, and its properties are examined experimentally.


Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.


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