Apparatus and method for in-situ endpoint detection for semiconductor processing operations

• US 8,795,029 B2
• Filed: 01/18/2013
• Issued: 08/05/2014
• Est. Priority Date: 03/28/1995
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Birang, Manoocher, Johansson, Nils, Gleason, Allan
• Primary Examiner(s): ROSE, ROBERT A
• Application Number:
  US13/745,691
• Publication Number:
  US 20130130413A1
• Time in Patent Office: 564 Days
• Field of Search: 451/5, 451/6, 451/7, 451/41, 451/288, 451/287, 451/533, 451/534, 451/527, 451/537, 451/285, 451/283, 451/11
• US Class Current: 451/6
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/205 provided with a window for inspecting the surface of the work being lapped
• CPC Class Codes: B24B 47/12 by mechanical gearing or electric power B24B47/16 takes precedence
• CPC Class Codes: B24B 49/04 involving measurement of the workpiece at the place of grinding during grinding operation
• CPC Class Codes: B24B 49/12 involving optical means
• CPC Class Codes: B24B 51/00 Arrangements for automatic control of a series of individual steps in grinding a workpiece if applicable to other machine tools, G05B takes precedence
• CPC Class Codes: G01B 11/0683 measurement during deposition or removal of the layer
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14

Abstract

An endpoint detection method includes processing an outer surface of a substrate, directing an incident light beam through a window in an opaque metal body onto the surface being processed, receiving at a detector a reflected light beam from the substrate and generating a signal from the detector, and generating a signal based on the reflected light beam received at the detector, and detecting a processing endpoint. The signal is a time-varying cyclic signal that varies as the thickness of the layer varies over time, and detecting the processing endpoint includes detecting that a portion of a cycle of the cyclic signal has passed, the portion being less than a full cycle of the cyclic signal.

Claims

1. An endpoint detection method, comprising:

processing an outer surface of a substrate, the processing changing a thickness of a layer at the outer surface over time;

during processing, directing an incident light beam through a window in an opaque metal body onto the surface being processed;

receiving at a detector of a monitoring system a reflected light beam from the substrate through the window and generating a signal from the detector, the reflected light beam being a combination of at least a reflection from the outer surface and a reflection from an inner surface of the layer on a side of the layer opposite the outer surface;

generating in the monitoring system a signal based on the reflected light beam received at the detector, wherein the signal generated in the monitoring system is a time-varying cyclic signal that varies as the thickness of the layer varies over time with a period of the cyclic signal determined by an index of refraction of the layer and a wavelength of the light beam;

detecting a processing endpoint by detecting from changes in the cyclic signal that a portion of a cycle of the cyclic signal has passed as a trigger to halt processing, the portion being less than a full cycle of the cyclic signal; and

halting processing upon detecting the processing endpoint.

2. The method of claim 1, wherein the incident light beam includes red light.

3. The method of claim 1, wherein generating the incident light beam comprises generating a laser beam.

4. The method of claim 1, wherein processing the outer surface of the substrate comprises reducing the thickness of the layer.

5. The method of claim 1, wherein the layer comprises a dielectric layer.

11. The method of claim 1, wherein the incident light beam is stationary.

6. An endpoint detection method, comprising:

processing an outer surface of a substrate, the processing changing a thickness of a layer at the outer surface over time;

during processing, directing an incident light beam through a window in an opaque metal body onto the surface being processed;

receiving at a detector of a monitoring system a reflected light beam from the substrate through the window and generating a signal from the detector, the reflected light beam being a combination of at least a reflection from the outer surface and a reflection from an inner surface of the layer on a side of the layer opposite the outer surface;

generating in the monitoring system a signal based on the reflected light beam received at the detector, wherein the signal generated in the monitoring system is a time-varying cyclic signal that varies as the thickness of the layer varies over time with a period of the cyclic signal determined by an index of refraction of the layer and a wavelength of the light beam;

detecting a processing endpoint including detecting from changes in the cyclic signal that at least one cycle of the cyclic signal has passed as a trigger to halt processing; and

halting processing upon detecting the processing endpoint.

7. The method of claim 6, wherein the incident light beam includes red light.

8. The method of claim 6, wherein generating the incident light beam comprises generating a laser beam.

9. The method of claim 6, wherein processing the outer surface of the substrate comprises reducing the thickness of the layer.

10. The method of claim 6, wherein the layer comprises a dielectric layer.

12. The method of claim 6, wherein the incident light beam is stationary.