Laser luminescence monitor for material thickness
First Claim
1. An apparatus for monitoring a change of thickness of a first material layer having a first bandgap wavelength energy, said first material layer for disposal over a second material layer on a wafer and having a second different bandgap wavelength energy, wherein at least one of said materials has a direct bandgap, comprising:
- means for holding said wafer and for changing the thickness of said first material layer at a particular location over said second material layer;
means for generating a beam of energy of an intensity and wavelength sufficient to pump said at least one direct bandgap material to a higher energy state;
means for directing said beam of energy to impinge at an angle on to the surface and to penetrate said wafer at said location wherein said first material layer thickness is being changed; and
means for detecting induced luminescence from said at least one direct bandgap material layer to determine when to stop said thickness changing means.
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Accused Products
Abstract
An apparatus and method for monitoring a change of thickness of a first material with a first bandgap energy, for disposal over a second material on a wafer and having a second different bandgap energy, wherein at least one of the materials has a direct bandgap. The apparatus comprises means for changing the thickness of the first material layer; means for directing a beam of energy to impinge at an angle on to the surface and to penetrate the wafer, with the beam having an energy sufficient to pump the at least one direct bandgap material to a higher energy state; and means for detecting the induced luminescence from the at least one direct bandgap material to determine when to alter the thickness changing process.
The present invention may be used to monitor both deposition and etching processes. It is particularly suited for determining the etch endpoint for III-V semiconductor materials such as GaAs and AlGaAs.
62 Citations
39 Claims
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1. An apparatus for monitoring a change of thickness of a first material layer having a first bandgap wavelength energy, said first material layer for disposal over a second material layer on a wafer and having a second different bandgap wavelength energy, wherein at least one of said materials has a direct bandgap, comprising:
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means for holding said wafer and for changing the thickness of said first material layer at a particular location over said second material layer; means for generating a beam of energy of an intensity and wavelength sufficient to pump said at least one direct bandgap material to a higher energy state; means for directing said beam of energy to impinge at an angle on to the surface and to penetrate said wafer at said location wherein said first material layer thickness is being changed; and means for detecting induced luminescence from said at least one direct bandgap material layer to determine when to stop said thickness changing means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for monitoring a change in thickness of a first material layer with a first bandgap energy, said first material layer for disposal over a second material layer formed on a wafer, with said second material layer having a different bandgap energy, wherein at least one of said material bandgaps is a direct bandgap, comprising the steps of:
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changing the thickness of said first material layer having said first bandgap energy at a particular location over said second material layer; generating a beam of energy of an intensity and wavelength sufficient to pump said at least one direct bandgap material layer to a higher energy state; directing said beam of energy to impinge at an angle on to the surface and to penetrate said wafer at said location where said first material thickness is being changed; and detecting induced luminescence from said at least one direct bandgap material layer to determine when to alter said thickness changing step. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification