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Integrate grounding contact in measurement structures to enable charge dissipation for XPS measurement

IP.com Disclosure Number: IPCOM000236383D
Publication Date: 2014-Apr-23
Document File: 2 page(s) / 48K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to incorporate the design of a grounding contact in the measurement structures, to provide an integrated grounding path for surface charges during inline X-Ray Photoelectron Spectroscopy (XPS) measurement.

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Integrate grounding contact in measurement structures to enable charge dissipation for XPS measurement

X-ray photoelectron spectroscopy (XPS) is a measurement technique widely used in Front End of Line (FEOL) to provide composition and thickness measurement for gate stacks. During XPS measurement, source x-ray promotes the excitation of photoelectrons, which are counted and analyzed based on the associated kinetic energy and intensity. If not sufficiently grounded, the unbalanced surface potential could impede the energy of photoelectrons and thus lead to shift in the energy spectrum
(i.e. shift of peak Binding Energy).

Figure 1: Shift of Binding Energy

When too much charge is accumulated on the examined surface area, degradation in peak shape and intensity occurs and reduces measurement accuracy (distorted signal peaks as shown in Figure 2). Charging is the main reason for reducing the accuracy, sensitivity, and reliability of inline XPS measurement.

Figure 2: Degradation in peak shape and intensity

Known solutions for charge compensation include flood gun, Ultra-Violet (UV) lights, Argon ion beam with electron beam, aperture, or mesh screen with low energy e-beam; however, these options are not perfect. For example, these options may increase complexity in instrumentation, cause contamination, modify device property (e.g., UV may induce property change of materials), and hence have not been implemented commercially in manufacturing environment. As a result, an...