Scanning electron microscope system for linewidth measurement of IC

1992 ◽  
Author(s):  
Cheon I. Eom ◽  
TaeBong Eom ◽  
Yeong-Uk Ko ◽  
Myung-Sai Chung
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Linewidth Measurement ◽  
Scanning Electron

Linewidth measurement using the low voltage SEM

1986 ◽  
Vol 44 ◽  
pp. 652-653
Author(s):  
M.G. Rosenfield
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Secondary Electron ◽  
Low Voltage ◽  
Fabrication Process ◽  
Critical Dimensions ◽  
Linewidth Measurement ◽  
Threshold Technique ◽  
Scanning Electron

Minimum feature sizes in experimental integrated circuits are approaching 0.5 μm and below. During the fabrication process it is usually necessary to be able to non-destructively measure the critical dimensions in resist and after the various process steps. This can be accomplished using the low voltage SEM. Submicron linewidth measurement is typically done by manually measuring the SEM micrographs. Since it is desirable to make as many measurements as possible in the shortest period of time, it is important that this technique be automated.Linewidth measurement using the scanning electron microscope is not well understood. The basic intent is to measure the size of a structure from the secondary electron signal generated by that structure. Thus, it is important to understand how the actual dimension of the line being measured relates to the secondary electron signal. Since different features generate different signals, the same method of relating linewidth to signal cannot be used. For example, the peak to peak method may be used to accurately measure the linewidth of an isolated resist line; but, a threshold technique may be required for an isolated space in resist.

Electron detection modes and their relation to linewidth measurement in the Scanning Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 646-649 ◽  
Author(s):  
M. T. Postek
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Primary Electron ◽  
Type I ◽  
Sample Type ◽  
Secondary Electrons ◽  
Basic Premise ◽  
Backscattered Electrons ◽  
Linewidth Measurement ◽  
Scanning Electron

The basic premise underlying the use of the scanning electron microscope (SEM) for linewidth measurement for semiconductor research and production applications is that the video image acquired, displayed, and ultimately measured reflects accurately the structure of interest. It should be understood that not all the secondary electrons detected originate at the point of impact with the primary electron beam. Those that do are referred to as Type I electrons. Some of the signal is contributed by re-emergent backscattered electrons creating secondary electrons at the surface of the sample (Type II electrons) and at the final lens polepiece (Type III electrons). Other signal contributions include line-of-sight backscattered electrons and other sources particular to each instrument (Type IV electrons). The effects of these four types of contributions to the actual image or linewidth measurement have not been fully evaluated. In measurement applications, error due to the actual location of signal origination will not affect pitch measurements as the errors cancel. However, in linewidth measurement, the errors are additive and thus give twice the edge detection error to the measured width. The basic intent of this work is to demonstrate the magnitude of these errors relative to the mode of signal detection at a variety of beam acceleration voltages.

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