Method and apparatus for evaluating surface roughness of an epitaxial growth layer, method and apparatus for measuring reflectance of an epitaxial growth layer, and manufacturing method of semiconductor device

• US 6,284,552 B1
• Filed: 11/13/1998
• Issued: 09/04/2001
• Est. Priority Date: 11/14/1997
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hashidume, Satoshi, Noguchi, Takashi, Yamagata, Hideo
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): Luk, Olivia T
• Application Number:
  US09/190,461
• Time in Patent Office: 1,026 Days
• Field of Search: 438/15, 438/29, 438/16, 438/14, 438/964
• US Class Current: 438/14
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence
• 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: Y10S 438/964 Roughened surface

Abstract

Correlation formulae having predetermined forms (i.e., straight lines representing relationships between the surface roughness of the reflectance) are determined in advance between measurement values of the ultraviolet reflectance of the surfaces of respective sample epitaxial growth layers obtained by using an ultraviolet spectrophotometer at a wavelength of 200 nm and measured values of the surface roughness of the same samples by using an atomic force microscope. The surface roughness of an ensuing measurement object is determined by measuring only its ultraviolet reflectance and substituting a resulting measurement value into the correlation formulae.

Claims

1. A method for evaluating surface roughness of an epitaxial growth layer formed on a substrate, comprising the steps of:

(a) measuring reflectance of epitaxial growth layers by applying ultraviolet light to surfaces of the respective epitaxial growth layers;

(b) determining a correlation between measurement values of the reflectance and surface roughness of the epitaxial growth layers; and

(c) wherein the ultraviolet light has a single wavelength between 190 and 210 nm.

2. The method according to claim 1, wherein specular reflectance of the epitaxial growth layers is measured by using an ultraviolet spectrophotometer with an incident angle of the ultraviolet light with respect to the surfaces of the respective epitaxial growth layers set at about 90°

.

3. The method according to claim 1, comprising the steps of:

measuring surface roughness of first epitaxial growth layers by using an atomic force microscope; and

determining a correlation between measurement values of the surface roughness and measurement values of ultraviolet specular reflectance of the first epitaxial growth layers.

4. The method according to claim 3, comprising the step of quantifying surface roughness of a second epitaxial growth layer by applying a measurement value of ultraviolet specular reflectance of the second epitaxial growth layer to the correlation.

5. The method according to claim 4, comprising the steps of:

determining a correlation formula of the correlation; and

determining the surface roughness of the second epitaxial growth layer by substituting the measurement value of the specular reflectance into the correlation formula.

6. The method according to claim 3, wherein the substrate is a silicon substrate and the epitaxial growth layer is a silicon epitaxial growth layer, and wherein correlations between measurement values of root-mean-square roughness RMS and a maximum height Rmax of surfaces of the first epitaxial growth layers obtained by using the atomic force microscope and the measurement values of the ultraviolet specular reflectance R of the first epitaxial growth layers are formulated as correlation formulae.

7. A method of measuring reflectance of an epitaxial growth layer formed on a substrate to evaluate surface roughness of the epitaxial growth layer, comprising the step of specular reflectance of the epitaxial growth layer with an ultraviolet spectrophotometer by applying ultraviolet light, the ultraviolet light having a single wavelength between 190 and 210 nm, to a surface of the epitaxial growth layer at an incident angle of about 90°

.

8. The method according to claim 7, wherein the substrate is a silicon substrate.

9. A manufacturing method of a semiconductor device comprising the step of forming an epitaxial growth layer on a semiconductor substrate, further comprising the steps of:

(a) measuring reflectance of epitaxial growth layers by applying ultraviolet light to surfaces of the respective epitaxial growth layers;

(b) determining a correlation between measurement values of the reflectance and surface roughness of the epitaxial growth layers; and

(c) wherein the ultraviolet light has a single wavelength between 210 and 290 nm.

10. The manufacturing method according to claim 9, further comprising the steps of:

evaluating surface roughness of an epitaxial growth layer based on the correlation; and

controlling conditions for forming an ensuing epitaxial growth layer based on an evaluation result of the surface roughness.

11. The manufacturing method according to claim 9, wherein the semiconductor substrate is a silicon substrate, the epitaxial growth layer is a silicon epitaxial growth layer as a base layer, and the semiconductor device is a vertical bipolar transistor.

12. The manufacturing method according to claim 9, wherein specular reflectance of the epitaxial growth layers is measured by using an ultraviolet spectrophotometer with an incident angle of the ultraviolet light with respect to the surfaces of the respective epitaxial growth layers set at about 90°

.

13. The manufacturing method according to claim 9, comprising the steps of:

measuring surface roughness of first epitaxial growth layers by using an atomic force microscope; and

determining a correlation between measurement values of the surface roughness and measurement values of ultraviolet specular reflectance of the first epitaxial growth layers.

14. The manufacturing method according to claim 13, comprising the step of quantifying surface roughness of a second epitaxial growth layer by applying a measurement value of ultraviolet specular reflectance of the second epitaxial growth layer to the correlation.

15. The manufacturing method according to claim 14, comprising the steps of:

determining a correlation formula of the correlation; and

determining the surface roughness of the second epitaxial growth layer by substituting the measurement value of the specular reflectance into the correlation formula.

16. The manufacturing method according to claim 13, wherein the substrate is a silicon substrate and the epitaxial growth layer is a silicon epitaxial growth layer, and wherein correlations between measurement values of root-mean-square roughness RMS and a maximum height Rmax of surfaces of the first epitaxial growth layers obtained by using the atomic force microscope and the measurement values of the ultraviolet specular reflectance R of the first epitaxial growth layers are formulated as correlation formulae.