INSPECTION SYSTEM AND APPARATUS

• US 20080162066A1
• Filed: 02/25/2008
• Published: 07/03/2008
• Est. Priority Date: 02/03/2003
• Status: Active Grant

• Current Assignee: Qcept Investments, LLC
• Original Assignee: Qcept Technologies, Inc.
• Inventors: STEELE, M. Brandon, Hawthorne, Jeffrey Alan
• Granted Patent: US 7,634,365 B2
• Time in Patent Office: Days
• US Class Current: 702/84
• CPC Class Codes: G01N 2033/0095 Semiconductive materials
• CPC Class Codes: G01N 27/002 by investigating the work function voltage
• CPC Class Codes: G01R 31/312 by capacitive methods

Abstract

A method and system for identifying a defect or contamination on a surface of a sample. The system operates by detecting changes in work function across a surface via both vCPD and nvCPD. It utilizes a non-vibrating contact potential difference (nvCPD) sensor for imaging work function variations over an entire sample. The data is differential in that it represents changes in the work function (or geometry or surface voltage) across the surface of a sample. A vCPD probe is used to determine absolute CPD data for specific points on the surface of the sample. The combination of vibrating and non-vibrating CPD measurement modes allows the rapid imaging of whole-sample uniformity, and the ability to detect the absolute work function at one or more points.

Claims

1. A system for inspection of a component having a surface with the component undergoing processing to provide a commercial product comprising:

a sample stage for receiving a component;

a drive system to move the component;

a contact potential difference sensor system including a non-vibrating contact potential difference probe and a vibrating contact potential difference probe;

the non-vibrating contact potential difference probe generating a relative contact potential difference signal characteristic of at least one of contaminants and physical defects at the surface of the component as a result of a change in the contact potential difference generated by relative motion of the non-vibrating contact potential difference probe and the component;

the vibrating contact potential difference probe generating an absolute contact potential difference signal characteristic of at least one of the contaminants and the physical defects at the surface of the component as a result of the change in the contact potential difference generated by the vibration of the vibrating contact potential difference probe while positioned over a point on the component; and

a computer system in communication with the contact potential difference sensor system, the computer system processing the relative contact potential difference signal and the absolute contact potential difference signal to inspect the surface of the component and provide analytical information about at least one of the contaminants and the physical defects of the surface of the component, thereby enabling quality control of the commercial product.

2. The system as defined in claim 1 further including an additional surface analysis system to provide supplementary chemical information.

3. The system as defined in claim 2 wherein the additional surface analysis system is selected from the group of TXRF, VPD-ICP-MS, SIMS, automated optical microscopy and laser backscattering.

4. The system as defined in claim 1 wherein the component is selected from the group of a semiconductor wafer and an integrated circuit.

5. The system as defined in claim 1 wherein the system for inspection comprises an in-line system.

6. The system as defined in claim 1 further including an imaging system to display the analytical information.

7. The system as defined in claim 1 further including a positioning assembly in communication with the contact potential difference sensor system, whereby the sensor system can be positioned relative to the component on the sample stage.

8. The system as defined in claim 1 further including a bias voltage system coupled to the component.

9. The system as defined in claim 1 further including a probe height sensor.

10. The system as defined in claim 1 wherein the contact potential difference sensor system comprises a plurality of at least one of the non-vibrating contact potential probe and the vibrating contact potential probe.

11. The system as defined in claim 1 wherein the computer system includes executable software to compare the contact potential difference signals with known chemical patterns to determine chemistry of the contaminants.

12. The system as defined in claim 1 wherein the computer system includes executable software to convert spatial data from the contact potential difference signal into frequency domain data to enable identifying peaks in the frequency domain with particular spatial characteristics.

13. The system as defined in claim 1 wherein the computer system includes executable software to process the non-vibrating contact potential difference signal into wavelet domain signals for removal of noise.

14. The system as defined in claim 1 wherein the computer system includes executable software to carry out an electronic filtering of the contact potential difference signals.

15. The system as defined in claim 1 further including a variable speed mechanical component to decrease velocity of the component in proportion to motion of the non-vibrating contact potential probe, thereby providing the probe with substantially even data exposure.

16. A system for inspection of a semiconductor wafer having a surface with the semiconductor wafer undergoing processing as part of an in-line fabrication system, comprising:

a sample stage for receiving a semiconductor wafer;

a drive system to move the semiconductor wafer;

a contact potential difference sensor system including a non-vibrating contact potential difference probe and a vibrating contact potential difference probe;

the non-vibrating contact potential difference probe generating a relative contact potential difference signal characteristic of at least one of contaminants and physical defects at the surface of the semiconductor wafer as a result of a change in the contact potential difference generated by relative motion of the non-vibrating contact potential difference probe and the semiconductor wafer;

the vibrating contact potential difference probe generating an absolute contact potential difference signal characteristic of at least one of the contaminants and the physical defects at the surface of the semiconductor wafer as a result of the change in the contact potential difference generated by the vibration of the vibrating contact potential difference probe while positioned over a point on the semiconductor wafer; and

a computer system in communication with the contact potential difference sensor system, the computer system processing the relative contact potential difference signal and the absolute contact potential difference signal to inspect the surface of the semiconductor wafer and provide analytical information about at least one of the contaminants and the physical defects of the surface of the semiconductor wafer, thereby enabling quality control of the semiconductor wafer as part of the in-line fabrication system.

17. The system as defined in claim 16 further including a test wafer to establish standards for at least one of the chemical contaminants and the physical defects.

18. The system as defined in claim 16 wherein the semiconductor wafer comprises an integrated circuit.

19. The system as defined in claim 16 further including an imaging system to display the analytical information.

20. The system as defined in claim 16 further including at least one of an additional surface analysis system, a probe height sensor, a bias voltage system and a positioning system.