Recent Developments in Automated Sample Preparation for FESEM

Author(s):  
R. R. Cerchiara ◽  
P. E. Fischione ◽  
J. J. Gronksy ◽  
W. F. Hein ◽  
D. D. Martin ◽  
...  

Abstract Standard analytical practice in the semiconductor industry depends on fast, efficient and reliable sample preparation prior to FESEM. “In lens” imaging technology and orientation mapping (EBSD) demand sample surfaces free of physical damage and residual contamination. An integrated preparation tool has been developed that incorporates the functionality necessary for argon – oxygen plasma cleaning, ion beam etching (IBE), reactive ion beam etching (RIBE), reactive ion etching (RIE), and ion beam sputter coating (IBSC). Control, monitoring and sequential automation of the processes is accomplished through a novel combination of software and hardware. FESEM results for Al and Cu based microelectronic materials will be discussed, as well as EBSD results for bulk metals. Improvements in throughput and subsequent materials characterization will be demonstrated.

Author(s):  
R. R. Cerchiara ◽  
H. A. Cook ◽  
P. E. Fischione ◽  
J. J. Gronsky ◽  
J. M. Matesa ◽  
...  

Abstract The SiLK resins, composed of aromatic hydrocarbons, are a family of highly cross-linked thermoset polymers with isotropic dielectric properties. Patterning of SiLK for high aspect ratio copper interconnects has depended on reactive ion etching with oxygen/nitrogen gas mixtures. Reactive ion etching is therefore also accomplished with reducing plasmas such as nitrogen/hydrogen. An additional plasma cleaning step can be inserted after the reactive ion etching (RIE) step, so that any residual contamination is removed prior to imaging or final sputter coating. Automated sample preparation of microelectronic materials containing high and low-k dielectrics for FESEM is accomplished in this article by combining these techniques: plasma cleaning, ion beam etching, and reactive ion etching. A single RIE chemistry was effective in etching both dielectrics as well as delineating the other phases present.


Author(s):  
R. R. Cerchiara ◽  
P. E. Fischione ◽  
M. F. Boccabella ◽  
A. C. Robins

Abstract A packaged device based on a ball grid array or other design presents a challenge to the failure analyst. Accessing one of the metal levels from the topside requires decapsulation by either a wet, predominantly dry (RIE) or a completely dry (mechanical) treatment. To reveal the details of the gate including the gate oxide, new approaches to selective etch delineation by RIE are required. This article presents an automated sample preparation method for packaged microelectronic materials by combining plasma cleaning, ion beam etching, reactive ion etching and ion beam sputter coating. A single etch gas chemistry was effective in phase delineation by RIE. Future work to further delineate the gate oxides could support accurate metrology by means of FESEM rather than field emission transmission electron microscope.


1996 ◽  
Vol 4 (1) ◽  
pp. 8-9
Author(s):  
Dave Laken

In the November issue of this publication, we described how focused ion beam (FIB) microsurgery is used to successfully cross-section and prepare material-specific samples for SEM and TEM analysis. Material specific samples have two or more components possessing different characteristics, such as hardness and chemical etch or sputtering rates. Traditional sample preparation techniques (mechanical grinding and polishing, broad ion beam etching, and chemical etching) alter, delaminate, or destroy these samples.FIB handles the preparation of these difficult samples well because of its milling geometry and the high current density of the small beam.


Author(s):  
Liew Kaeng Nan ◽  
Lee Meng Lung

Abstract Conventional FIB ex-situ lift-out is the most common technique for TEM sample preparation. However, the scaling of semiconductor device structures poses great challenge to the method since the critical dimension of device becomes smaller than normal TEM sample thickness. In this paper, a technique combining 30 keV FIB milling and 3 keV ion beam etching is introduced to prepare the TEM specimen. It can be used by existing FIBs that are not equipped with low-energy ion beam. By this method, the overlapping pattern can be eliminated while maintaining good image quality.


1999 ◽  
Vol 5 (S2) ◽  
pp. 932-933
Author(s):  
W. Li ◽  
S. Q. Wang ◽  
R. Trussell ◽  
M. Xu ◽  
R.D. Venables ◽  
...  

The continued reduction in the size of critical features in integrated circuits has resulted in the need to develop rapid, site-specific, sectioning techniques to enable efficient physical characterization of the structures of interest. We have implemented a mechanical polishing approach to achieve this objective with the additional goals of maximizing the number of targeted sites in a sample that can be analyzed, and minimizing physically destructive procedures, such as ion beam exposure. Precision sample preparation approaches have been under investigation for both transmission electron microscopy and scanning electron microscopy.The mechanical specimen preparation approach used in this work is a variant of the well-known wedge polishing technique. Here we use a polishing tool that does not contact the grinding surface, thus allowing precise control of the wedge angle. Prior to sample preparation, the polishing tool head was precision aligned parallel to the platen.


Author(s):  
L. A. Giannuzzi ◽  
P. R. Howell ◽  
H. W. Pickering ◽  
W. R. Bitler

A primary concern involving transmission electron microscopy (TEM) analysis is whether the electron transparent region under investigation is representative of the bulk material. TEM is frequently employed to examine the microstructure of electrodeposited materials due to their small grain size and high dislocation density. Previous work in this laboratory on palladium electrodeposits has shown that deformation twins and diffusion induced recrystallization may be induced during preparation of thin foils using both twin jet electropolishing and ion beam thinning. Recent developments in TEM sample preparation in the physical sciences include a procedure for the cross-section of heterogeneous layered materials which reduces or eliminates the need for ion milling. In this sample preparation technique, a tripod polisher device is used to mechanically polish the specimen to electron transparency. The purpose of this paper is to report on the influence of the tripod polisher sample preparation technique, on the microstructure of zinc electrodeposits.


Author(s):  
Wayne D. Kaplan ◽  
Kim Kisslinger ◽  
Ron Oviedo ◽  
Efrat M. Raz ◽  
Colin Smith

Abstract The rising demand in the semiconductor industry for higher spatial resolution in the analysis of device defects has focused attention on the use of transmission electron microscopy (TEM). However, conventional TEM sample preparation may be difficult and time-consuming, and depending on the operator may result in a low yield of quality specimens. One solution to this problem is the use of focused ion beam (FIB) milling for the final stage of TEM sample preparation. However, specimens have to be mechanically thinned prior to FIB processing, and the need to characterize specific devices requires a pre-FIB preparation method to isolate specific regions on the wafer. An innovative and automated solution that isolates specific devices and prepares TEM specimens for subsequent thinning by FIB has been developed. Based on controlled microcleaving technology, the system automatically performs the pre-FIB preparation in less than 30 minutes. An important added benefit is that the target area to be analyzed can be positioned at a specific distance from the sample edge, thereby facilitating the final FIB milling stage. The thinned specimen is automatically packaged for subsequent FIB processing and TEM. Details of the method and examples showing TEM results from tungsten filled vias are presented.


2000 ◽  
Vol 8 (5) ◽  
pp. 14-19 ◽  
Author(s):  
Wayne D. Kaplan ◽  
Efrat Raz ◽  
Colin Smith

The rising demand in the semiconductor industry for higher spatial resolution in the analysis of device defects has focused attention on the use of transmission electron microscopy (TEM). However, conventional TEM sample preparation can be difficult and time-consuming, and, depending on the operator, may result in a low yield of quality specimens. One solution to this problem is the use of focused ion beam (FIB) milling for the final stage of TEM sample preparation. However, specimens have to be mechanically thinned prior to FIB and the need to characterize specific devices requires a pre-FIB preparation method that can target specific features on the wafer. We will discuss an innovative and automated solution that isolates specific devices and prepares TEM specimens for subsequent FIB thinning. The complete pre-FIB preparation takes less than 30 minutes and yields a sample in which the targeted feature is positioned a specific distance from the sample edge, thereby minimizing final FIB milling time. The output specimen is automatically packaged for FIB milling and TEM analysis. We also present drawings of the process flow and examples showing TEM results from tungsten filled vias.


1996 ◽  
Vol 4 (6) ◽  
pp. 24-25
Author(s):  
John F. Walker

Part 1 of this series described how focused ion beam (FIB) microsurgery is used to successfully cross-section and prepare materialspecific samples for SEM and TEM analysis. In Part 2, we detailed how FIB is also the tool of choice to prepare site-specific samples, particularly for transmission electron microscopy (TEM) analysis. In this final article of this series, we describe actual sample preparation, cutting a selected area la size and mounting it on a grid for FIB preparation. Focused ion beams are very useful in preparing TEM specimens that have unique characteristics. In particular, the ability of such systems to image submicron features within a structure has allowed accurate identification of the precise place to make a membrane.


2003 ◽  
Vol 9 (S02) ◽  
pp. 804-805
Author(s):  
R.R. Cerchiara ◽  
P.E. Fischione ◽  
J.J. Gronsky ◽  
W.F. Hein ◽  
J.M. Matesa ◽  
...  

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