Apparatus for integrated monitoring of wafers and for process control in the semiconductor manufacturing and a method for use thereof

• US 6,426,502 B1
• Filed: 05/22/2000
• Issued: 07/30/2002
• Est. Priority Date: 11/08/1998
• Status: Expired due to Fees

• Current Assignee: Nova Measuring Instruments Limited (Honeywell International Inc.)
• Original Assignee: Nova Measuring Instruments Limited (Honeywell International Inc.)
• Inventors: Finarov, Moshe
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): Israel, Andrew
• Application Number:
  US09/509,080
• Time in Patent Office: 799 Days
• Field of Search: 250/348, 250/347, 250/338.1, 250/559.23
• US Class Current: 250/348
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/681 using optical controlling means

Abstract

The present invention relates to an integrated apparatus for monitoring wafers and for process control in the semiconductor manufacturing process, by means of optical measurements at more than one spectral range that can be installed inside any part of the semiconductor production line, i.e., inside the photocluster equipment, the CVD equipment or the CMP equipment. The apparatus comprises a measuring unit (110) for performing optical measurements in predetermined sites on said wafer, illumination sources for illuminating said wafer via measuring unit (10,50), supporting means (30) for holding, rotating and translating the wafer and a control unit (120). The measuring unit (110) comprises: (a) at least two separate optical units, each operating at a different distinct spectral range; (b) a separate optical window for each optical unit (31, 32); (c) at least one movable optical head (34); (d) mechanical means for translating said optical head relatively to the wafer'"'"'s surface.

Claims

1. An integrated apparatus for monitoring a semiconductor wafer and for process control in a semiconductor production line by means of optical measurements in more than one spectral ranges, said apparatus comprising:

a measuring unit for performing the optical measurements at predetermined locations on the wafer;

light sources for illuminating the wafer,

a supporting element for holding, rotating and translating the wafer; and

a control unit coupled to and controlling said measuring unit, said supporting element and said light sources;

wherein said measuring unit comprises;

a) at least two separate optical units operating in different distinct spectral ranges;

b) at least two separate elongated optical windows which are spaced from each other by a distance d and through which the wafer is illuminated, each of said optical windows corresponding to one of said optical units and having a length equal to or longer than a radius of the wafer;

c) a movable optical head which accommodates some or all of optical components of said optical units; and

d) a positioning element for translating said optical head relatively to a surface of the wafer along the length of said optical windows and along an axis perpendicular to the surface of the wafer, so that each of said optical units can measure an area of the wafer through the corresponding optical window and perform autofocusing.

2. The apparatus according to claim 1, wherein either said supporting element or said positioning element is configured to perform an accurate linear translation, along a direction perpendicular to the length of said optical windows, within a distance equal to a center-to center distance Δ

x of said optical windows.

3. The apparatus according to claim 1, wherein said positioning element comprises rails on which said optical head is mounted, and a motor which drives a screw connected to said optical head to move said optical head along the rails.

4. The apparatus according to claim 1, wherein said measuring unit is placed in a sealed enclosure.

5. The apparatus according to claim 1, wherein at least one of said light sources is external to said measuring unit, and light generated by said at least one light source is conveyed to said measuring unit by a suitable light guide.

6. The apparatus according to claim 1, wherein movable parts of more than one of said optical units are installed in said movable optical head.

7. The apparatus according to claim 1, further comprising a plurality of said moveable optical heads, movable parts of each of said optical units are installed in separate one of said movable optical heads.

8. The apparatus according to claim 1, wherein said apparatus is installed inside processing equipment in the semiconductor production line.

9. The apparatus according to claim 8, wherein said processing equipment is one of Chemical Vapor Deposition, Chemical Mechanical Polishing, and photocluster equipment.

10. The apparatus according to claim 1, wherein said apparatus is attached to processing equipment in the semiconductor production line.

11. The apparatus according to claim 10, wherein said processing equipment is one of Chemical Vapor Deposition, Chemical Mechanical Polishing, and photocluster equipment.

12. The apparatus according to claim 1, wherein said apparatus is installed inside one of cooling chambers of cluster Chemical Vapor Deposition equipment in the semiconductor production line.

13. The apparatus according to claim 1, wherein said apparatus is installed in the vicinity of a cassette load/unload station of non-cluster Chemical Vapor Deposition equipment in the semiconductor production line.

14. The apparatus according to claim 1, wherein one of said optical units comprises a visible illumination source and optical components suitable for optical measurements in the visible spectral range, and another of said optical units comprises optical components and illumination sources suitable for optical measurements in a spectral range other than the visible spectral range, or at a specific wavelength.

15. The apparatus according to claim 14, wherein the optical unit operating in the visible spectral range further includes an optical imaging device.

16. The apparatus according to claim 1, wherein the measuring unit comprises first and second said optical units;

the first optical unit comprises a visible illumination source and optical components suitable for optical measurements in the visible spectral range, signals generated by the first optical unit are relayed to said positioning element for positioning the moveable optical head relatively to the wafer and used for thin layer thickness measurements; and

the second optical unit comprises an infrared illumination source and optical components suitable for optical measurements in the infrared spectral range, signals generated by the second optical unit are used for layer composition measurements and a contamination analysis.

17. The apparatus according to claim 1, wherein the measuring unit comprises first and second said optical units;

the first optical unit comprises a visible illumination source and optical components suitable for optical measurements in the visible spectral range, signals generated by the first optical unit are relayed to said positioning element for positioning the moveable optical head relatively to the wafer and used for thin layer thickness measurements; and

the second optical unit comprises an ultraviolet illumination source and optical components suitable for optical measurements in the ultraviolet spectral range, the second optical unit further comprises a detector for receiving and measuring ultraviolet light reflected off the wafer after being illuminated thereon by the ultraviolet illumination source.

18. The apparatus according to claim 1, wherein the measuring unit comprises first and second said optical units;

the first optical unit comprises a visible illumination source and optical components suitable for optical measurements in the visible spectral range, signals generated by the first optical unit are relayed to said positioning element for positioning the moveable optical head relatively to the wafer and used for thin layer thickness measurements; and

the second optical unit comprises an X-ray illumination source and optical components suitable for optical measurements in the X-ray spectral range, the second optical unit further comprises a detector for receiving and measuring an X-ray beam reflected off the wafer after being illuminated thereon by the X-ray illumination source.

19. The apparatus according to claim 1, wherein one of the windows can be opened for a predetermined period of time.

20. An integrated apparatus for monitoring a semiconductor wafer and for process control in a semiconductor production line by means of optical measurements in more than one spectral ranges, said apparatus comprising:

a measuring unit for performing the optical measurements at predetermined locations on the wafer;

light sources for illuminating the wafer,

a supporting element for holding, rotating and translating the wafer; and

a control unit coupled to and controlling said measuring unit, said supporting element and said light sources;

wherein said measuring unit comprises;

a) more than two separate optical units operating in different distinct spectral ranges;

b) more than two separate adjacent optical windows through which the wafer is illuminated, each of said optical windows corresponding to one of said optical units and being elongated in an elongation direction;

c) at least one movable optical head which accommodates some or all of optical components of said optical units; and

d) a positioning element for translating said at least one optical head relatively to the wafer'"'"'s surface along the elongation direction, so that each of said optical units can measure an area of the wafer through the corresponding optical window and perform autofocusing; and

wherein either said supporting element or said positioning element is configured to either perform a continuous translation along a transverse direction perpendicular to the elongation direction of said optical windows or have several accurate positions along the transverse direction.

21. An integrated apparatus for monitoring a semiconductor wafer and for process control in a semiconductor production line by means of optical measurements in more than one spectral ranges, said apparatus comprising:

a measuring unit for performing the optical measurements at predetermined locations on the wafer;

light sources for illuminating the wafer,

a supporting element for holding, rotating and translating the wafer; and

a control unit coupled to and controlling said measuring unit, said supporting element and said light sources;

wherein said measuring unit comprises;

a) at least two separate optical units operating in different distinct spectral ranges;

b) at least two separate optical windows through which the wafer is illuminated, each of said optical windows corresponding to one of said optical units;

c) at least one movable optical head which accommodates some or all of optical components of said optical units; and

d) a positioning element for translating said at least one optical head relatively to a surface of the wafer, so that each of said optical units can measure an area of the wafer through the corresponding optical window and perform autofocusing; and

wherein one of the windows can be opened for a predetermined period of time.