Image analysis – Applications – Manufacturing or product inspection
Reexamination Certificate
1998-07-16
2002-03-12
Mancuso, Joseph (Department: 2623)
Image analysis
Applications
Manufacturing or product inspection
C382S149000, C382S153000, C382S144000
Reexamination Certificate
active
06356653
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to method and apparatus for combined particle location and removal. More specifically, this invention relates to method and apparatus for combined particle location and removal from the surface of a semiconductor wafer by focusing energy from a focused energy source, such as a laser, onto the located particles.
2. Description of the Related Art
In the manufacture of microelectronic devices, particularly VLSI and ULSI devices, in which the overall dimensions of devices are becoming smaller and more closely packed, and the critical dimensions are becoming much smaller, particle contamination is of increasing concern. The presence of particles during growth, deposition, or etching of thin films can cause voids, dislocations or shorts which adversely affect performance and reliability of the devices. Accordingly, one step in the manufacturing process is the cleaning of the device's surface to remove particulate contamination. Thereafter, it may be necessary to inspect the cleaned surface to insure that it has been cleaned adequately of the contaminants and not damaged by the cleaning process.
Many procedures for detecting particles on the surface of semiconductor devices and generating locational data for the detected particles have been developed in the prior art. Typically, the particles are detected by laser beam irradiation. The surface of the device is irradiated with a laser beam from one direction and reflected from the surface. The presence of the particles on the surface causes the reflection of the laser beam to scatter at the areas where the particles are present. The sizes and distribution of the particles on the surface are then determined from the scattering intensity of the reflected beam. Variations of this method have been developed for detecting smaller and smaller particle sizes.
Conventionally, device surfaces are cleaned to reduce the particulate contaminants using a chemical wash. The chemical wash ideally removes most of the particles which could cause a defect in the resulting device. However, smaller particles and larger, more difficult to remove particles usually remain on the surface after the chemical wash. The removal of the remaining particles typically requires subsequent chemical washes using harsh chemicals and/or procedures. These subsequent washes are often detrimental to the device surface and add additional cycle time and cost.
Furthermore, the prior art removal techniques do not make any determination of the amount of cleaning necessary based upon the particle size and composition, substrate material and/or particle location. Additionally, the prior art techniques do not differentiate between particles on the surface of a wafer which are in regions that are of no interest or in sensitive areas where there is no need to remove the particles, and those particles that are in regions where it is necessary to remove the particles. Thus, in the prior art techniques, all regions of the wafer are treated and cleaned similarly.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a method and apparatus for combined location and removal of particles on the surface of an object.
It is another object of the present invention to provide a method and apparatus for combined location and removal of particles on the surface of an object without damaging the surface of the object.
It is still another object of the present invention to provide a method and apparatus for combined location and removal of particles on the surface of an object which uses only the amount of cleaning force necessary to remove the particle.
It is still another object of the present invention to provide a method and apparatus for combined location and removal of particles on the surface of an object in which the amount of energy used to remove the particle is based upon the particle's size and/or composition.
It is yet still another object of the present invention to provide a method and apparatus for combined location and removal of particles on the surface of an object which is capable of not effecting the removal of the particle if the particle is in a region of the surface which is either of no interest or which is sensitive to the removal process.
Accordingly, a method for removing one or more particles from a surface of an object is provided. The method comprises first and second steps of detecting and locating the plurality of particles on the surface of the object. In a third step, focused energy is directed onto one or more of the located particles to break a bond energy between the one or more particles and the surface thereby removing the one or more particle from the surface. In preferred variations of the method of the present invention, the object is a semiconductor wafer and the directed focused energy is in the form of a laser.
Also provided is an apparatus for removing the one or more particles from the surface of the object. The apparatus comprises means for detecting and locating the one or more particles on the surface of the object, and means for directing focused energy on one or more of the located particles to break a bond energy between the one or more particles and the surface thereby removing the one or more particles from the surface.
In a first variation of the present invention, method and means for detecting the composition of the one or more located particles are also provided. The amount of focused energy directed at the one or more detected particles is then based upon the detected composition of the one or more particles and/or the particle size.
In a second variation of the present invention, also provided are method and means for determining whether the particle location is or is not in an area of interest, and deciding not to undertake the directing of the laser upon the one or more particles if it is determined that the one or more particles are not located in an area of interest.
In a third variation of the present invention, also provided are method and means for determining whether the detected particle has been removed after the directing step, and repeating the directing and detecting steps with focused energy of increasing power until it is determined that the one or more particle have been removed.
In a fourth variation of the present invention, also provided are method and means for overriding the repeating of the directing and detecting steps if a predetermined number of directing steps have been performed without removing the particle upon which the focused energy is directed.
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Brigante Jeffrey A.
Gale Glenn W.
Hevey Maurice R.
Kern, Jr. Frederick W.
Kim Ben
Bali Vikkram
Chadurjian Mark F.
Mancuso Joseph
Scully Scott Murphy & Presser
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