Measuring an alignment target with a single polarization state
Granted: January 31, 2006
Patent Number:
6992764
An alignment target includes periodic patterns on two elements. The periodic patterns are aligned when the two elements are properly aligned. By measuring the two periodic patterns with an incident beam having a single polarization state and detecting the intensity of the resulting polarized light, it can be determined if the two elements are aligned. The same polarization state may be detected as is incident or different polarization states may be used. A reference measurement location…
Method and apparatus for using an alignment target with designed in offset
Granted: January 3, 2006
Patent Number:
6982793
An alignment target includes periodic patterns on two elements. The alignment target includes two locations, at least one of which has a designed in offset. In one embodiment, both measurement locations have a designed in offset of the same magnitude but opposite directions. For example, two separate overlay patterns that are mirror images of each other may be used. Alternatively, the magnitudes and/or directions may vary between the measurement locations. The radiation that interacts…
Encoder measurement based on layer thickness
Granted: November 29, 2005
Patent Number:
6970255
An encoder includes a layer on the scale that has a thickness that varies as a function of position along the length of the scale. The position of the sensor head with respect to the scale may be determined by measuring the thickness of the layer or index of refraction, e.g., using a reflectometer, and converting the thickness to the lateral position. In one embodiment, the thickness of the layer is used to provide a rough position of the sensor head with respect to the scale and an…
Encoder with an alignment target
Granted: October 25, 2005
Patent Number:
6958819
An encoder uses an alignment target that includes periodic patterns on the movable element and the stationary element. The alignment target may include at least two measurement locations, each location having a different offset between the periodic pattern on the movable element with respect to the periodic pattern on the stationary element. Alternatively, two measurements using different polarization states may be made at one location. When the periodic patterns on the movable element…
Measuring an alignment target with multiple polarization states
Granted: September 27, 2005
Patent Number:
6949462
An alignment target includes periodic patterns on two elements. The periodic patterns are aligned when the two elements are properly aligned. By measuring the two periodic patterns at multiple polarization states and comparing the resulting intensities of the polarization states, it can be determined if the two elements are aligned. A reference measurement location may be used that includes third periodic pattern on the first element and a fourth periodic pattern on the second element,…
Leveling a measured height profile
Granted: August 9, 2005
Patent Number:
6925860
The height profile of a sample that includes at least one film on a substrate is leveled based on the measured thickness of the overlying film. An apparatus that levels the height profile includes a metrology tool that generates the height profile of a sample and a metrology tool that measures the thickness of one or more layers of a film stack on top of a substrate at two or more locations. The measured thickness is then used to level the height profile to reduce any tilt error before a…
Precision polar coordinate stage
Granted: June 28, 2005
Patent Number:
6910847
A polar coordinate stage that may be used in a chamber includes a rotating chuck that moves in a linear direction and has the motors that drive the motion of the chuck outside the chamber. The stage can include a linkage of arms to support and drive the linear motion of the chuck. The chuck is coupled to a horizontal rail such that rotational motion of a first arm is translated into precise linear motion of the chuck along the horizontal rail through a second arm. In addition, a system…
Measurement of diffracting structures using one-half of the non-zero diffracted orders
Granted: May 24, 2005
Patent Number:
6898537
A process of modeling a diffracting structure with normally incident radiation and the radiation diffracted from the structure includes constructing an optical model of the diffracting structure and calculating spectral information for the optical model based on a plurality of diffracted orders using either the positive or negative of each of said plurality of diffracted orders and the zero order. The process may be used to measure a diffracting structure, in which spectral information…
Method of measuring small pads on a substrate
Granted: February 22, 2005
Patent Number:
6859279
A method of measuring a small area on a substrate with an ellipsometer, comprising orienting a substrate with respect to the ellipsometer such that an elliptical light spot produced by the ellipsometer fits diagonally within the test area. Then measuring the surface properties of the substrate within the test area with the ellipsometer.
Optical metrology system with combined interferometer and ellipsometer
Granted: February 15, 2005
Patent Number:
6856384
An interferometer and ellipsometer are combined in a metrology tool to measure the step height of a sample, which may include transparent layers. The metrology tool includes a shared light source that provides a light beam for an interferometer and a light beam for an ellipsometer, interferometer optics which direct the light beam for an interferometer to reflect off of a sample and ellipsometer optics which direct the light beam for an ellipsometer to reflect off a sample, and a…
Stage with two substrate buffer station
Granted: February 15, 2005
Patent Number:
6854948
A stage used, e.g., in semiconductor fabrication, includes a two substrate buffer station and a movable chuck. The buffer station, in one embodiment is fixed, i.e., non-movable relative to the stage. In another embodiment, the support elements of the buffer station may move in unison vertically or horizontally. In another embodiment, a pair of the support elements horizontally moves toward another pair of support elements to reduce the necessary horizontal motion of the chuck. For…
Enhanced throughput of a metrology tool
Granted: February 8, 2005
Patent Number:
6853873
The throughput of a metrology module is enhanced by measuring a first parameter of a processed substrate and only measuring additional parameters if warranted from an analysis of the first parameter. Thus, after a substrate is processed, a first parameter related to the processing is measured and analyzed. If the measured parameter falls within accepted tolerance, the data is reported and then next substrate is processed. If, however, the measured parameter falls outside the range of…
Configurable metrology device that operates in reflectance mode, transmittance mode, or mixed mode
Granted: January 11, 2005
Patent Number:
6842251
A metrology system includes a sample holder and a backside reflective element. The backside reflective element causes light that is transmitted through the sample to be reflected and transmitted a second time, in the opposite direction, through the sample. A variable collection range can be adjusted to place the sample, the reflective element or both within the collection range. The collection range is the range of focused light that will be detected. The system can be controlled to move…
High precision substrate prealigner
Granted: December 28, 2004
Patent Number:
6836690
A prealigner includes a light source and light detector that detects the position of the periphery of a substrate as a rotary chuck rotates the substrate. The prealigner includes a processor that receives and records the peripheral position of the substrate relative to the angular position of the substrate. The prealigner determines the center of the substrate by fitting a curve to the recorded data set, after eliminating any spikes in the data, e.g., caused by the notch or parts of the…
Method of determining material using intensity of light
Granted: November 2, 2004
Patent Number:
6813031
A profiling method compensates for phase changes associated with the presence of multiple or varying material in the area to be measured. The profiling method measures at least a portion of the height profile of the area of interest. The phase of the different materials in the region are also obtained and used to generate a correction factor. Depending on the type of material in the region of interest, the correction factor may be the material specific phase difference of the materials…
Compact rotating stage
Granted: August 24, 2004
Patent Number:
6779278
A compact stage includes a rotary driver and a vertical linear driver that are in the same horizontal plane, which advantageously reduces the height of the device. The stage may include a rotating shaft to which a chuck is mounted. A rotary drive, which may be an annular rotary drive, is coupled to and rotates the rotating shaft. A linear drive is also coupled to the rotating shaft and in one embodiment extends through the center of the annular rotary drive. The linear drive moves the…
Method of generating calibration data for relative height measurement
Granted: August 10, 2004
Patent Number:
6772620
A metrology process, in accordance with the present invention, measures the dishing of a first feature made of a first material by determining the relative height of the first feature with respect to a second feature, where the first and second features have different dishing rates. The relative height of the first feature with respect to the second feature may be determined by measuring a first relative height of the first feature with respect to a reference location, measuring a second…
Substrate surface profile and stress measurement
Granted: July 13, 2004
Patent Number:
6762846
The focusing capability of a metrology tool is used to determine the surface profile of a substrate and the stress on the substrate that is associated with processing step, such as layer deposition or etching. The amount of focusing adjustment necessary to place the substrate in focus is used to determine the height of the surface of the substrate at three or more locations. Based on the surface profile, a curvature parameter may be calculated. The curvature parameter may be calculated…
Combination of normal and oblique incidence polarimetry for the characterization of gratings
Granted: March 30, 2004
Patent Number:
6713753
A normal incidence spectroscopic polarimeter is combined with an oblique incidence spectroscopic polarimeter to provide an accurate characterization of complex grating structures, e.g., structures with sloping sidewalls, with notches and with multiple underlying layers. The normal incidence spectroscopic polarimeter includes a polarizing element that is in the path of the normal incidence light beam such that the light beam is transmitted through the polarizing element before reaching…
Method of measuring dishing
Granted: March 23, 2004
Patent Number:
6710888
A metrology process, in accordance with the present invention, measures the dishing of an opaque feature with respect to a relatively transparent feature that surrounds the opaque feature on a production substrate by measuring only height variation of the opaque feature. The opaque feature may be, for example, a metal or metal alloy line containing, e.g., copper, aluminum, or tungsten, while the relatively transparent feature is a dielectric material. The metrology process is useful, for…
