Ade Optical Systems Corporation

Ade Corporation

The Scatter Works Inc.

Vlsi Standards, Inc.

John C Stover

Michael E Fossey

Lee Dante Clementi

Craig A Scheer

Yuri A Eremin

Bradley W Scheer

Songping Gao

Vladimir I Ivakhnenko

In a method for depositing particles onto a substrate a flow of gas containing particles is provided along a flow path that bypasses a deposition chamber. The flow path may direct the flow of the gas containing the particles to a vacuum. To deposit particles onto a substrate in the deposition chamber, the flow path of the gas containing the particles is diverted into the deposition chamber so that particles are deposited onto the substrate. After a desired amount of particles have been deposited onto the substrate, the flow path of the flow of the gas containing the particles is changed to the flow path that bypasses the deposition chamber. A particle deposition system and a method for maintaining particle diameter during deposition of particles onto a substrate also are described.

Particle deposition system with enhanced speed and diameter accuracy

In an optical inspection system, defects such as particles, pits, subsurface voids, mounds, or other defects occurring at or near the smooth surface of a substrate are classified by type and size based on the magnitude S of a signal produced by collected light for each of a plurality N of different test configurations, yielding a plurality of signal magnitudes S through S . A database is consulted, comprising a relationship of S versus defect size d for each test configuration and for each of a plurality of idealized defect types, so as to determine a defect size d corresponding to each measured signal magnitude S, and an average defect size is determined for each defect type. Signal magnitudes <S > through <S > that would be produced by a defect of the average size are determined for each defect type, and defect type is determined based on a smallest deviation between the measured magnitudes and the determined magnitudes.

Method and apparatus for classifying defects occurring at or near a surface of a smooth substrate

A surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides for detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Wafer inspection system for distinguishing pits and particles

P-polarized light or having a strong P-polarized component is directed onto a filmed substrate at two (or more) different incidence angles, one angle being relatively large and the other angle being relatively small as measured from a surface normal. Light that is scattered into a back region of the hemispherical space above the substrate surface is collected and the intensity of the collected light is measured for each of the two incident angles. A defect can be classified as either a hole in the film or a particle on the film based on the relative intensities of the collected light.

Method for discriminating between holes in and particles on a film covering a substrate

Particles are distinguished from pits, voids, scratches, and other subsurface defects in a surface of a substrate by impinging the defect with polarized light and integrating light scattered by the defect over a wide angular range to produce a total integrated response. Using a P-polarized incident light beam, particles are distinguished from subsurface defects by comparing the total integrated responses, which vary with changes in the incident angle. Alternatively, the defect is impinged with a P-polarized incident beam at a defined incident angle, and is then impinged with an S-polarized beam at the same incident angle. Total integrated responses are measured for both beams and a P-to-S ratio of the responses is calculated. Particles are distinguished from subsurface defects by comparing the P-to-S ratio to a predetermined threshold value which separates particles from subsurface defects.

Method and apparatus for distinguishing particles from subsurface defects on a substrate using polarized light

The composition of a particle occurring on the surface of a smooth substrate is identified by impinging the surface with a light beam having a strong P-polarized component at an oblique angle of incidence to the surface, and collecting light scattered from the surface at forward, center, and back locations relative to the portion of the surface impinged by the incident beam. The intensities of the light collected at these locations are measured by detectors and converted into signals, and the magnitudes of the signals are compared to correlations of particle material as a function of the relative magnitudes of the forward-, center-, and back-scatter signals so as to identify the material whose correlation most nearly matches the measured detector signals. Preferably, a ratio of the back detector signal magnitude to forward detector signal magnitude is correlated with particle material and back detector signal magnitude. Alternatively or additionally, a ratio of back detector signal magnitude to center detector signal magnitude is correlated with particle material and back detector signal magnitude. Average particle diameter versus back detector signal magnitude is correlated with particle material.

Methods and apparatus for identifying the material of a particle

The method of the present invention accurately measures the diameter of a particle resting on a surface through use of a beam of known wavelength being directed at the surface at an incident angle. Scattered light measurements are taken as the beam contacts the surface and the particle. Scattered light measurements are separated into their respective P and S power components. During all measurements, the beam source remains constant in that it is not moved or adjusted for intensity or polarization. The P and S power components of the background measurements are subtracted from the P and S power components of the particle measurements to give net P and S power components. From the net P and S power components the net P and S components of the differential scatter cross section may be derived as is known in the art. Different ratios may be formed from the differential scatter cross section to eliminate many of the intensity errors inherent in the use of scattered light measurements. These ratios are sensitive to particle diameter but insensitive to absolute light measurements. A model, known in the art for its accuracy, is used to calculate scattered light of the particle. The model results are used to form the same ratios as a function of particle diameter and are then compared to the ratios from the measured data. Based on this comparison, the diameter of the spherical particle is determined.

Process for particle size measurement

A metrology standard that is useful for calibrating instruments for the levels of microroughness encountered in semiconductor, disk drive, and related industries today. In advanced applications, this level is about 5 .ANG. rms in a 0.01-1.0 .mu.m.sup.-1 spatial bandwidth range. This standard uses a one-dimensional square wave pattern etched in a silicon wafer to reduce the effects of instrument spatial bandwidth. The standard has approximately a 20 .mu.m pitch with feature depths as small as 8 .ANG..

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North Attleboro, MA, United States of America

John C Stover