Methods and systems for determining a critical dimension and overlay of a specimen

• US 7,751,046 B2
• Filed: 03/27/2003
• Issued: 07/06/2010
• Est. Priority Date: 09/20/2000
• Status: Expired due to Fees

• Current Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Original Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Inventors: Abdulhalim, Ibrahim, Smedt, Rodney, Bultman, Gary, Brown, Kyle A., Nikoonahad, Mehrdad, Levy, Ady, Wack, Dan, Fielden, John
• Primary Examiner(s): Chowdhury; Tarifu
• Assistant Examiner(s): Stock, Jr.; Gordon J
• Application Number:
  US10/401,242
• Publication Number:
  US 20040235205A1
• Time in Patent Office: 2,658 Days
• Field of Search: 356399-401, 430/5, 430/22, 430/30
• US Class Current: 356/401
• CPC Class Codes: G01N 2021/646 Detecting fluorescent inhomogeneities at a position, e.g. for detecting defects
• CPC Class Codes: G01N 2021/8825 Separate detection of dark field and bright field
• CPC Class Codes: G01N 21/211 Ellipsometry optical thickness measurement G01B11/06
• CPC Class Codes: G01N 21/27 using photo-electric detection G01N21/31 takes precedence; circuits for computing concentration logarithmic circuits G06G7/24; photometric circuits in general G01J
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence
• CPC Class Codes: G01N 21/636 using an arrangement of pump beam and probe beam; using the measurement of optical non-linear properties; non-linear optics per se G02F1/35
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G03F 7/70616 Monitoring the printed patterns
• CPC Class Codes: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
• CPC Class Codes: G03F 7/70633 Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
• CPC Class Codes: G03F 7/7065 Defects, e.g. optical inspection of patterned layer for defects
• CPC Class Codes: G03F 7/70658 Electrical testing
• CPC Class Codes: G03F 7/707 Chucks, e.g. chucking or un-chucking operations or structural details
• CPC Class Codes: G03F 7/70708 being electrostatic; Electrostatically deformable vacuum chucks
• CPC Class Codes: H01J 2237/31701 Ion implantation
• 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 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Methods and systems for monitoring semiconductor fabrication processes are provided. A system may include a stage configured to support a specimen and coupled to a measurement device. The measurement device may include an illumination system and a detection system. The illumination system and the detection system may be configured such that the system may be configured to determine multiple properties of the specimen. For example, the system may be configured to determine multiple properties of a specimen including, but not limited to, critical dimension and overlay misregistration. In this manner, a measurement device may perform multiple optical and/or non-optical metrology and/or inspection techniques.

Claims

1. A method for controlling layers alignment in a multi-layer sample, the method comprising the steps of:

(i) providing a measurement site on said sample including two regions located one above the other in two different layers, respectively, said regions containing patterned structures, wherein said site is located on an upper surface of the sample;

(ii) illuminating said site and a bottom surface of the sample with electromagnetic radiation and detecting a diffraction efficiency of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures;

(iii) analyzing said diffraction efficiency to determine an existing lateral shift between the layers;

(iv) detecting the electromagnetic radiation propagating from the bottom surface of the sample; and

(v) determining a presence of defects on the bottom surface of the sample from the electromagnetic radiation propagating from the bottom surface of the sample.

2. The method of claim 1, further comprising providing at least one additional site on said sample including two regions located one above the other in the two different layers, respectively, said regions in said at least one additional site containing patterned structures, illuminating said at least one additional site with the electromagnetic radiation, detecting a diffraction efficiency of radiation diffracted from the patterned structures in said at least one additional site, and analyzing the diffraction efficiencies obtained in said site and said at least one additional site to determine the existing lateral shift between the layers.

3. The method of claim 1, wherein said detecting the diffraction efficiency comprises measuring said diffraction efficiency as a function of wavelength.

4. The method of claim 1, wherein said detecting the diffraction efficiency comprises measuring said diffraction efficiency as a function of angle of incidence.

5. The method of claim 1, wherein said illuminating comprises illuminating said site with polarized light with different states of polarization.

6. The method of claim 1, wherein said multi-layer sample is a semiconductor wafer.

7. The method of claim 1, wherein said patterned structures are two-dimensional.

8. The method of claim 7, wherein said illuminating comprises illuminating said site with polarized light with different states of polarization.

9. A method, comprising:

directing electromagnetic radiation toward an area of an upper surface of a specimen and a bottom surface of the specimen, wherein the area on the upper surface comprises features formed on a first level of the specimen and features formed on a second level of the specimen, and wherein the first level is formed above the second level;

detecting the electromagnetic radiation scattered from the area on the upper surface of the specimen and the electromagnetic radiation propagating from the bottom surface of the specimen, wherein said directing the electromagnetic radiation toward the area on the upper surface and said detecting the electromagnetic radiation scattered from the area on the upper surface are performed using spectroscopic scatterometry;

determining a measure of displacement of a lateral position of the features on the first level of the specimen with respect to a lateral position of the features on the second level of the specimen from the scattered electromagnetic radiation; and

determining a presence of defects on the bottom surface of the specimen from the electromagnetic radiation propagating from the bottom surface of the specimen.

10. The method of claim 9, wherein the specimen comprises a substrate suitable for fabrication of semiconductor devices.

11. The method of claim 9, further comprising determining a property of the features on the first level or the second level from the scattered electromagnetic radiation, wherein the property comprises a period, a width, a step height, a sidewall angle, or a profile.

12. A method, comprising:

directing electromagnetic radiation toward an area on an upper surface of a specimen and a bottom surface of the specimen, wherein the area on the upper surface comprises features formed on a first level of the specimen and features formed on a second level of the specimen, and wherein the first level is formed above the second level;

detecting the electromagnetic radiation scattered from the area on the upper surface of the specimen and the electromagnetic radiation propagating from the bottom surface of the specimen, wherein said directing the electromagnetic radiation toward the area on the upper surface and said detecting the electromagnetic radiation scattered from the area on the upper surface are performed using spectroscopic ellipsometry;

determining a measure of displacement of a lateral position of the features on the first level of the specimen with respect to a lateral position of the features on the second level of the specimen from the scattered electromagnetic radiation; and

determining a presence of defects on the bottom surface of the specimen from the electromagnetic radiation propagating from the bottom surface of the specimen.

13. A method, comprising:

directing electromagnetic radiation toward an area on an upper surface of a specimen and a bottom surface of the specimen, wherein the area on the upper surface comprises a periodic pattern of features formed on a first level of the specimen and a periodic pattern of features formed on a second level of the specimen, and wherein the first level is formed above the second level;

detecting the electromagnetic radiation diffracted from the area on the upper surface of the specimen and the electromagnetic radiation propagating from the bottom surface of the specimen;

determining a measure of displacement of a lateral position of the features on the first level of the specimen with respect to a lateral position of the features on the second level of the specimen from the diffracted electromagnetic radiation;

determining a property of the features on the first level or the second level from the diffracted electromagnetic radiation, wherein the property comprises a period, a width, a step height, a sidewall angle, or a profile; and

determining a presence of defects on the bottom surface of the specimen from the electromagnetic radiation propagating from the bottom surface of the specimen.