EP0352740A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Laser interferometer system for monitoring and controlling IC processing
Assignee: Applied Materials Inc
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Filing: 1989-07-25
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Granted: —
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Expires: 2009-07-25
Abstract
Abstract A laser end point detector incorporating adjustable-focus, variable-orientation detection optics for monitoring different types of structures such as laser-transparent thin films, isolated trenches or holes and patterned arrays of trenches or holes. A collector lens package comprising a laser and a focusing lens are mounted in a hole in a collector lens which is pivotally mounted for selectively focusing zero, first and higher orders of diffractions reflected from the wafer onto an associated detector to monitor the etching of different types of structures. For example, zero order diffraction signals are used to monitor the etching of large target areas in transparent thin films or of non-patterned trenches of holes. First order (or higher) diffraction signals are used for monitoring the etching of patterned features which effect a two-dimensional diffraction grating, such as the capacitor holes in dynamic random access memories.
Inventors
- 👤 David Cheng
- 👤 Robert P. Hartlage
- 👤 Wesley W. Zhang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 09:40
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32917; H01J37/32935; G; G01; G01B; G01B11/00; G01B11/22
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
86 words
A laser interferometer system for monitoring the etching of a workpiece, comprising: a laser; means for detecting laser light reflected from a surface of the workpiece; means for analyzing the detected light to monitor at least one of etch rate, etch depth and etch-through of a selected layer of the workpiece; and, a collector lens mounting the laser therein, said collector lens being pivotally mounted in said laser interferometer relative to said workpiece surface to intercept selected diffraction orders of light reflected from said workpiece surface.
Claim 2
Dependent Claim
86 words
A laser interferometer system for monitoring the etching of a workpiece, comprising: a laser; means for detecting laser light reflected from a surface of the workpiece; means for analyzing the detected light to monitor at least one of etch rate, etch depth and etch-through of a selected layer of the workpiece; and, a collector lens mounting the laser therein, said collector lens being pivotally mounted in said laser interferometer relative to said workpiece surface to intercept selected diffraction orders of light reflected from said workpiece surface.
Claim 3
Dependent Claim
24 words
The system of Claim 1, wherein said collector lens further mounts a lens therein for focusing light from the laser onto said workpiece surface.
Claim 4
Dependent Claim
153 words
A reactor system for etching a workpiece and automatically terminating etching upon reaching a given condition selected from a predetermined etch depth and etch-through of a selected layer on the workpiece, comprising: a chamber for etching a workpiece therein, said chamber having a window formed in one wall thereof; and a laser interferometer system mounted adjacent said window and comprising a laser unit oriented for directing a beam of coherent light through said window onto a layer on said workpiece; means for detecting laser light reflected from the workpiece; a collector lens mounting the laser unit therein, said collector lens being pivotally mounted adjacent said window relative to said workpiece layer to reflect selected diffraction orders of light from said workpiece layer onto said detector; and means responsive to signals from said detector for terminating etching upon reaching a given condition selected from a given etch depth and etch-through of said selected layer.
Claim 5
Dependent Claim
153 words
A reactor system for etching a workpiece and automatically terminating etching upon reaching a given condition selected from a predetermined etch depth and etch-through of a selected layer on the workpiece, comprising: a chamber for etching a workpiece therein, said chamber having a window formed in one wall thereof; and a laser interferometer system mounted adjacent said window and comprising a laser unit oriented for directing a beam of coherent light through said window onto a layer on said workpiece; means for detecting laser light reflected from the workpiece; a collector lens mounting the laser unit therein, said collector lens being pivotally mounted adjacent said window relative to said workpiece layer to reflect selected diffraction orders of light from said workpiece layer onto said detector; and means responsive to signals from said detector for terminating etching upon reaching a given condition selected from a given etch depth and etch-through of said selected layer.
Claim 6
Dependent Claim
23 words
The system of Claim 3, wherein said collector lens further mounts a lens therein for focusing light from the laser onto said workpiece.
Claim 7
Dependent Claim
81 words
A process for monitoring the etching of a layer of material on a substrate, comprising: focusing a laser beam onto a target area of the substrate layer so that the laser light is reflected off the substrate layer at a selected orientation relative to the substrate and to a light detector so that a selected diffraction order of light is incident on said detector; and converting the resulting optical interference signal into a corresponding electrical signal for monitoring the fabrication process.
Claim 8
Dependent Claim
81 words
A process for monitoring the etching of a layer of material on a substrate, comprising: focusing a laser beam onto a target area of the substrate layer so that the laser light is reflected off the substrate layer at a selected orientation relative to the substrate and to a light detector so that a selected diffraction order of light is incident on said detector; and converting the resulting optical interference signal into a corresponding electrical signal for monitoring the fabrication process.
Claim 9
Dependent Claim
69 words
The method of Claim 5, wherein the target area on the substrate is selected from (1) material which is transparent to the laser light and a hole being etched in the substrate and (2) a pattern of etched features serving as a two-dimension diffraction grating to said incident laser light and wherein said selected diffraction order is, respectively, (1) the zero order and (2) a first or higher order.
References Cited (Backward Citations)
No citation records indexed.
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