scholarly journals Enhanced Sample Preparation of Cu Low-k Semiconductors via Mechanical Polishing and Ion Beam Etching

2004 ◽  
Vol 12 (1) ◽  
pp. 41-43
Author(s):  
Shane Roberts ◽  
Daniel Flatoff

Modern microelectronics have rapidly decreased in geometry to enhance the speed and processing power of computers. Advanced devices are approaching design rules of sub 0.13 micron in size, and the trend continues at the rate dictated by Moore's Law, Coupled with this reduction in device size, is a change in materials used for producing these devices. Traditional aluminum interconnect metallurgy and oxide dielectric materials are being replaced with copper and low-kmaterials in an effort to continue the trend of shrinking device sizes and higher processing capacities.These changes in materials and device sizes have provided the impetus for alternative methods for producing cross sections. Although focused ion beam instrumentation has been successfully used for preparing cross sections, a combinatorial approach using polishing and argon ion milling has been found to dramatically enhance the ability to produce high quality cross sectional samples in a reasonably short amount of time.

1997 ◽  
Vol 480 ◽  
Author(s):  
M. W. Phaneuf ◽  
N. Rowlands ◽  
G. J. C. Carpenter ◽  
G. Sundaram

AbstractFocused Ion Beam (FIB) systems have been steadily gaining acceptance as specimen preparation tools in the semiconductor industry. This is largely due to the fact that such instruments are relatively commonplace as failure analysis tools in semiconductor houses, and are commonly used in the preparation of cross-sections for imaging under the ion beam or using an electron beam in an SEM. Additionally, the ease with which cross-sectional TEM specimens of semiconductor devices can be prepared using FIB systems has been well demonstrated. However, this technology is largely unknown outside the semiconductor industry. Relatively few references exist in the literature on the preparation of cross-sectional TEM specimens of non-semiconductor materials by FIB. This paper discusses a specific use of FIB technology in the preparation of cross-sectional TEM specimens of non-semiconductor samples that are difficult to prepare by conventional means. One example of such materials is commercial galvannealed steel sheet that is used to form corrosion resistant auto-bodies for the automobile industry. Cross-sectional TEM specimens of this material have proved difficult and time-intensive to prepare by standard polishing and ion milling techniques due to galvanneal's inherent flaking and powdering difficulties, as well as the different sputtering rates of the various Fe-Zn intermetallic phases present in the galvannealed coatings. TEM results from cross-sectional samples of commercial galvannealed steel coatings prepared by conventional ion milling and FIB techniques are compared to assess image quality, the size of the electron-transparent thin regions that can be readily prepared and the quality of samples produced by both techniques. Specimen preparation times for both techniques are reported.


2006 ◽  
Vol 983 ◽  
Author(s):  
Yuhong Wu ◽  
Meng Qu ◽  
Lucille A Giannuzzi ◽  
Sanjay Sampath ◽  
Andrew Gouldstone

AbstractThermally sprayed (TS) coatings are widely used for surface engineering across a range of industries, including aerospace, infrastructure and biomedical. TS materials are formed via the successive impingement, rapid quenching and build-up of molten powder particles on a substrate. The impacted ‘splats’ are thus the fundamental microstructural constituents of the coatings, and their intrinsic properties, as well as intersplat bonding and morphology, dictate coating behavior. Beyond the obvious practical considerations, from a scientific standpoint, splats represent a fascinating template for study, due to the highly non-equilibrium processing conditions (rapid deceleration from sub-sonic velocities, million-degree/sec cooling rates). In the literature, many studies of isolated splats on substrates have been carried out, but these have focused on overall morphology (disc-shape vs fragmented). Direct observations of microstructure, in particular cross-section, are limited in the specimen preparation stage due to splat size (tens of microns in diameter, 1-2 microns in thickness). However, Focused Ion Beam (FIB) techniques have allowed this problem to be addressed in a robust manner; in this paper we will discuss such approaches to observe Ni5Al splats on stainless steel substrates. Cross-sections through the splat and the substrate were created by recourse to ion milling and the ion beam itself provided good channeling contrast for grain imaging. The typical splat microstructure with sub-micron Ni(Al) columnar grains, a chill zone at the bottom and a lift off area is observed in high detail. In addition, an amorphous aluminum oxide top layer of 100-200 nm is partially present on top of the Ni(Al) columnar grains. At the splat/substrate interface, defects such as micro- and nano-scale pores were characterized for the first time and will be discussed. These observations provide insights into splat and interface formation during the deposition process and may drastically improve our current understanding of Ni5Al splat properties.


1990 ◽  
Vol 199 ◽  
Author(s):  
Kyung-ho Park

ABSTRACTA procedure for preparing cross-sectional TEM specimens by focused ion beam etching (FIB) of specific regions on an integrated circuit chip is outlined. The investigation of the morphology, structure and local chemistry of precisely selected regions of semiconductor devices becomes increasingly important since the lateral dimensions and layer thickness of device structures are continually being reduced. The standard technique of preparing specimens for TEM, whether planar or cross-sectional, cannot select particular small regions. Some techniques and a number of tools and fixtures have been proposed which allow us to prepare TEM specimen of prespecified locations in complex devices. Most of these techniques, however, are still very difficult, tedious process and time consuming.A new technique has been proposed recently involving the use of FIB. The technique ensures that the preselected area of submicron scale will be located in the electron transparent section used for TEM imaging, in preparation turn-around time of about two hours. The TEM imaging of specific contacts via hole in a VLSI chip is illustrated.


2009 ◽  
Vol 17 (6) ◽  
pp. 20-23 ◽  
Author(s):  
Suhan Kim ◽  
Gao Liu ◽  
Andrew M. Minor

Focused ion beam (FIB) instrumentation has proven to be extremely useful for preparing cross-sectional samples for transmission electron microscopy (TEM) investigations. The two most widely used methods involve milling a trench on either side of an electron-transparent window: the “H-bar” and the “lift-out” methods [1]. Although these two methods are very powerful in their versatility and ability to make site-specific TEM samples, they rely on using a sacrificial layer to protect the surface of the sample as well as the removal of a relatively large amount of material, depending on the size of the initial sample. In this article we describe a technique for making thin film cross-sections with the FIB, known as Shadow FIBing, that does not require the use of a sacrificial layer or long milling times [2].


2014 ◽  
Vol 20 (6) ◽  
pp. 1826-1834
Author(s):  
Enne Faber ◽  
Willem P. Vellinga ◽  
Jeff T.M. De Hosson

AbstractThis paper investigates the adhesive interface in a polymer/metal (polyethylene terephthalate/steel) laminate that is subjected to uniaxial strain. Cross-sections perpendicular to such interfaces were created with a focused ion beam and imaged with scanning electron microscopy during straining in the electron microscope. During in situ straining, glide steps formed by the steel caused traction at the interface and initiated crazes in the polyethylene terephthalate (PET). These crazes readily propagated along the free surface of the PET layer. Similar crazing has not been previously encountered in laminates that were pre-strained or in numerical calculations. The impact of focused ion beam treatments on mechanical properties of the polymer/metal laminate system was therefore investigated. It was found that mechanical properties such as toughness of PET are dramatically influenced by focused ion beam etching. It was also found that this change in mechanical properties has a different effect on the pre-strained and in situ strained samples.


1999 ◽  
Vol 5 (S2) ◽  
pp. 902-903
Author(s):  
F. Shaapur ◽  
D. Brazeau ◽  
B. Foran

Focused ion beam (FIB) thinning of materials to electron transparency is now a routine procedure for preparation of specimens for transmission electron microscopy (TEM) of microelectronic materials and devices. The nano-scale structural damage, including implantation and amorphization due to this ion milling process has been well investigated and documented. In this paper, we discuss the micro-scale structural damage observed in copper/low-k materials and our efforts to minimize the extent of the damage without compromising the overall specimen preparation time.Figure 1 shows an area-specific cross-sectional specimen prepared from a copper/low-k via-chain test structure using the FIB-milling technique. The procedure involved mechanical thinning of a transverse wafer sliver followed by FIB-milling the area of interest to electron transparency according to conventional steps and conditions' using a liquid Ga+ ion source FIB system. The evidence of structural damage in terms of melting and/or sputtering of the metallization is visible at different areas.


Author(s):  
R. Alani ◽  
R. J. Mitro ◽  
W. Hauffe

Abstract The semiconductor industry routinely prepares crosssectional SEM specimens using several traditional techniques. Included in these are cleaving, mechanical polishing, wet chemical etching and focused ion beam (FIB) milling. This presentation deals with a new alternate method for preparation of SEM semiconductor specimens based upon a dedicated broad ion beam instrument. Offered initially as an alternative to wet chemical etching, the instrument was designed to etch and coat SEM and metallographic specimens in one vacuum chamber using inert gas (Ar) ion beams. The system has recently undergone further enhancement by introducing iodine Reactive Ion Beam Etching (RIBE) producing much improved etching/cleaning capabilities compared with inert gas ion beam etching. Further results indicate Ar broad ion beam etching can offer a rapid, simple, more affordable alternative (to FIB machines) for precision cross sections and for “slope cutting,” a technique producing large cross-sections within a short time frame. The overall effectiveness of this system for iodine RIBE etching, for precision cross sectioning and “slope cutting” will be shown for a number of traditional and advanced semiconductor devices.


1998 ◽  
Vol 523 ◽  
Author(s):  
N. I. Kato ◽  
K. Tsujimoto ◽  
N. Miura

AbstractIn focused ion beam (FIB) fabrication of cross-sectional transmission electron microscopy (X-TEM) specimens, highly accelerated ion beams sometimes cause serious damage. The damage can be induced in both the specimen surface and in the side walls. We used X-TEM observations to investigate the side-wall damage induced by FIB fabrication in crystalline silicon. The damaged layer was found to be about 20 nm thick in the case of 30-keV FIB etching. We tried to reduce the damage by several methods, such as gas-assisted etching (GAE) with iodine, broad argon ion milling and wet etching. The damaged layer was 19 nm for GAE and 12 nm for argon ion milling with a beam current of 70 mA and the tilt angle between the beam and the specimen of 15 degrees. Wet etching using a mixture of nitric and hydrofluoric acid removes most of the damaged layer.


Sign in / Sign up

Export Citation Format

Share Document