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US 7,248,367 B2Granted
Characterization of ultra shallow junctions in semiconductor wafers
AssigneeTherma-Wave, Inc.
InventorsAlex Salnik, Lena Nicolaides, Jon Opsal
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AssigneeTherma-Wave, Inc.
InventorsAlex Salnik, Lena Nicolaides, Jon Opsal
Estimating the term…
To measure USJ profile abruptness, a PMR-type optical metrology tool is to perform a series of two or more measurements, each with different pump/probe beam separations. Quadrature (Q) and in-phase (I) measurements are obtained for each measurement and used to derive a line in I-Q space. An abruptness measurement is derived by comparing the line slope to a similar line slope obtained for a sample having a known USJ profile. USJ profile depth is measured by obtaining quadrature (Q) values for one or more measurements. Each Q value is translated to a corresponding depth measurement using a table or similar lookup device.
A method of evaluating the abruptness of a junction in a semiconductor sample, the method comprising:
A method of evaluating the abruptness of a junction in a semiconductor sample comprising:
A method of evaluating the abruptness of a junction in a semiconductor sample, the method comprising:
A method of evaluating the abruptness of a junction in a semiconductor sample comprising:
A method of characterizing a semiconductor sample, the method comprising:
A method of evaluating two or more properties of a junction formed in a semiconductor sample, the method comprising:
A method of evaluating the incompleteness of an annealing process and/or the presence of surface states of a semiconductor sample, the method comprising:
Dependencies are inferred from the claim text.
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Using electron beams: of integrated circuits
Systems in which incident light is modified in accordance with the properties of the material investigated: with a modulation of one or more…
Measuring electric variables
Investigating or analysing materials by determining their chemical or physical properties
Term ended 28 Mar 2025 (estimated)
The subject invention relates to optical devices used to non-destructively evaluate semiconductor wafers. In particular, the present invention relates to methods for characterizing ultra shallow junctions in semiconductors.
As semiconductor geometries continue to shrink, manufacturers have increasingly turned to optical techniques to perform non-destructive inspection and analysis of semiconductor wafers. Optical techniques typically apply an incident beam (often referred to as a probe beam) to a sample and then detect and analyze the reflected energy. This type of inspection and analysis is known as optical metrology and is performed using a range of different optical techniques.
One widely used type of optical metrology is known as photo modulated reflectance or PMR. As shown in FIG. 1A, a typical PMR-type system includes a pump laser and a probe laser. The pump laser intensity is varied to create an intensity-modulated pump beam. The pump beam is projected against the surface of a sample and absorbed causing localized excitation of the sample. As the pump laser is modulated, the localized excitation (and subsequent relaxation) creates a train of thermal and plasma waves within the sample. These waves reflect and scatter off various features and interact with various regions within the sample in a way that alters the flow of heat and/or plasma from the pump beam spot.
FIGS. 1A and 1B show prior art optical metrology systems.
FIG. 2 show secondary ion mass spectroscopy (SIMS) concentration profiles obtained for six samples having different USJ depths and abruptnesses.
FIG. 3 shows a prior art method of correlating photo modulated reflectivity measurements to USJ profile abruptness.
The present invention includes a series of methods for characterizing USJ profiles. As will be described in the following sections, this includes methods for characterizing USJ abruptness, USJ depth and anneal incompleteness.
USJ Abruptness Variable Beam Separation Method
To measure profile abruptness, a PMR system of the type generally shown in FIG. 1B is used. During inspection, a series of two or more measurements are made. For each successive measurement, the beam scanner component of the PMR system is used to change the separation between the pump and probe beams producing a range of separations between zero (coincident pump and probe beams) and one μm. At each separation, I and Q measurements are obtained.