Apparatus for optical inspection of wafers during polishing

• US 6,368,181 B1
• Filed: 02/04/2000
• Issued: 04/09/2002
• Est. Priority Date: 05/23/1995
• Status: Expired due to Term

• Current Assignee: Nova Measuring Instruments Limited (Honeywell International Inc.)
• Original Assignee: Nova Measuring Instruments Limited (Honeywell International Inc.)
• Inventors: Haimovich, Eli, Finarov, Moshe, Dvir, Eran, Shulman, Beniamin
• Primary Examiner(s): Morgan, Eileen P.
• Application Number:
  US09/498,926
• Time in Patent Office: 795 Days
• Field of Search: 451/6, 451/41, 451/54, 451/63, 451/285, 451/287, 451/288
• US Class Current: 451/6
• CPC Class Codes: B24B 37/005 Control means for lapping machines or devices
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 49/12 involving optical means
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/6838 with gripping and holding devices using a vacuum; Bernoulli devices
• 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
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

An optical system is disclosed for the inspection of wafers during polishing which also includes a measurement system for measuring the thickness of the wafer'"'"'s top layer. The optical system views the wafer through a window and includes a gripping system, which places the wafer in a predetermined viewing location while maintaining the patterned surface completely under water. The optical system also includes a pull-down unit for pulling the measurement system slightly below the horizontal prior to the measurement and returns the measuring system to the horizontal afterwards.

Claims

1. A semiconductor article processing apparatus comprising:

a processing unit having a working area for processing a top layer of an article;

an optical measurement station adjacent to said processing unit; and

a transporter for transporting said article between said processing unit and said optical measurement station;

said optical measurement station located outside said working area and comprising;

an optical measuring unit for measuring a desired parameter of said top layer and;

a holding unit for receiving and holding said article in a stationary measurement position;

said holding unit having a window, through which at least a portion of the top layer of said article is viewable by said optical measuring unit.

2. The apparatus of claim 1, wherein said working area contains a working medium and said holding unit contains a connecting medium having properties similar to those of said working medium.

3. The apparatus of claim 2, wherein said processing unit is a polisher.

4. The apparatus of claim 3, wherein said optical measurement unit comprises a spectrophotometer.

5. The apparatus of claim 4, wherein said optical measurement station measures a thickness of at least a top layer of said article.

6. The apparatus of claim 3, wherein said article is a semiconductor wafer.

7. The apparatus of claim 5, wherein said optical measurement unit comprises an imager for imaging said article in order to carry out said thickness measurements of said top layer on pre-determined features of the article'"'"'s pattern.

8. A method for processing the surface of a semiconductor article, having at least one layer thereon comprising the steps of:

applying processing to said surface of said semiconductor article in a working area of a processing unit, wherein said step of processing is performed in a working medium;

conveying said article from said working zone into a measuring area of an optical measurement station located outside said working zone and adjacent to said processing unit, wherein said measuring area is separated from said optical assembly of said optical measurement station by a substantially transparent window;

holding said article in a fixed position; and

measuring a desired parameter of at least one layer of said article surface through said transparent window.

9. The method of claim 8, wherein said measuring area contains a uniform connecting medium transposed between said measuring area and said window.

10. The method of claim 9, wherein said uniform connecting medium has properties similar to those of said working medium.

11. The method of claim 10, wherein said step of processing is chemical mechanical polishing and wherein said processing unit is a polisher.

12. The method of claim 11, wherein said uniform connecting medium is water.

13. The method of claim 9, wherein said desired parameter is thickness of said at least one layer.

14. The method of claim 9, wherein said step of measuring comprises making a spectrophotometric measurement.

15. The method of claim 14, wherein said article comprises a semiconductor wafer.