Thin film thickness measuring method and thin film thickness measuring system

Abstract

A method for measuring thin film thickness includes generating a terahertz emitted electromagnetic wave, which is then incident on a test object after passing through an optical element. The test object includes a plurality of interface layers, and the optical element is used to adjust an incident angle of the terahertz emitted electromagnetic wave onto the test object. The optical element detects a plurality of terahertz received electromagnetic waves reflected after the terahertz emitted electromagnetic wave is incident on the plurality of interface layers of the test object. Based on the terahertz emitted electromagnetic wave and the plurality of terahertz received electromagnetic waves, a plurality of characteristic signals are measured. The plurality of characteristic signals are analyzed to determine a plurality of characteristics of the plurality of interface layers. The plurality of characteristics include the thickness of a surface layer among the plurality of interface layers.

Claims

1. A method for measuring thin film thickness, comprising: generating a terahertz emitted electromagnetic wave, which is then incident on a test object after passing through an optical element mounted on a slide rail mechanism, wherein the test object comprises a plurality of interface layers, and the optical element is used to adjust an incident angle of the terahertz emitted electromagnetic wave onto the test object; detecting a plurality of terahertz received electromagnetic waves reflected after the terahertz emitted electromagnetic wave is incident on the plurality of interface layers of the test object through the optical element; measuring a plurality of characteristic signals based on the terahertz emitted electromagnetic wave and the plurality of terahertz received electromagnetic waves; and analyzing the plurality of characteristic signals to determine a plurality of characteristics of the plurality of interface layers; wherein... The plurality of characteristics include the thickness of a surface layer among the plurality of interface layers; wherein the material of the optical element is selected from at least one of silicon, glass and Teflon, and the shape of the optical element is a triangular prism or a semi-cylindrical shape, and the slide rail mechanism can translate or rotate the optical element so that the incident angle of the terahertz emitted electromagnetic wave can be adjusted to be greater than one of the critical angles of the test object.

2. The thin film thickness measurement method as described in claim 1, wherein the plurality of characteristic signals includes an electric field intensity and an electric field phase for each terahertz received electromagnetic wave.

3. The thin film thickness measurement method as described in claim 1, wherein the plurality of characteristic signals further includes a spectral electric field between the plurality of terahertz received electromagnetic waves, including an electric field amplitude and an electric field phase.

4. The thin film thickness measurement method as described in claim 1, wherein the terahertz emitted electromagnetic wave comprises linear polarization, circular polarization, or elliptical polarization.

5. The thin film thickness measurement method as claimed in claim 1, wherein the plurality of characteristics further includes at least one of a warpage, a stress, a doping concentration, an optical coefficient, and an electrical coefficient for each of the plurality of interface layers.

6. The thin film thickness measurement method as described in claim 1, wherein the material of the test object is selected from at least one of a compound, an insulator, a semiconductor, and a metal.

7. The thin film thickness measurement method as described in claim 1, wherein the test object is a semiconductor wafer, the plurality of interface layers include an epitaxial layer and a substrate, and the plurality of characteristics include the thickness of the epitaxial layer.

8. The thin film thickness measurement method as described in claim 1, wherein the test object is a semiconductor package structure, the plurality of interface layers include a protective layer, an insulating layer, a conductive layer, a substrate and a wafer, and the plurality of characteristics include the thickness of the protective layer.

9. The thin film thickness measurement method as described in claim 1, wherein the test object is a printed circuit board, the plurality of interface layers include a copper clad laminate, a half-cured sheet, a copper foil, a solder resist layer and a character layer, and the plurality of characteristics include the thickness of the solder resist layer.

10. A thin film thickness measurement system, comprising: a terahertz electromagnetic wave generator for generating a terahertz emitted electromagnetic wave; an optical element mounted on a slide rail mechanism for incidenting the terahertz emitted electromagnetic wave onto a test object and adjusting an incident angle of the terahertz emitted electromagnetic wave onto the test object, wherein the test object comprises a plurality of interface layers; a terahertz electromagnetic wave receiver for detecting, through the optical element, a plurality of terahertz received electromagnetic waves reflected after the terahertz emitted electromagnetic wave is incident on the plurality of interface layers of the test object; and a detection device for measuring a plurality of characteristic signals based on the terahertz emitted electromagnetic wave and the plurality of terahertz received electromagnetic waves, and analyzing the plurality of characteristic signals to determine a plurality of characteristics of the plurality of interface layers; wherein... The plurality of characteristics include the thickness of a surface layer among the plurality of interface layers; wherein the material of the optical element is selected from at least one of silicon, glass and Teflon, and the shape of the optical element is a triangular prism or a semi-cylindrical shape, and the slide rail mechanism can translate or rotate the optical element so that the incident angle of the terahertz emitted electromagnetic wave can be adjusted to be greater than one of the critical angles of the test object.

11. The thin film thickness measurement system as claimed in claim 10, wherein the plurality of characteristic signals include an electric field intensity and an electric field phase for each terahertz received electromagnetic wave.

12. The thin film thickness measurement system as claimed in claim 10, wherein the plurality of characteristic signals further include a spectral electric field between the plurality of terahertz received electromagnetic waves, including an electric field amplitude and an electric field phase.

13. The thin film thickness measurement system as claimed in claim 10, wherein the terahertz emitted electromagnetic wave comprises linear polarization, circular polarization, or elliptical polarization.

14. The thin film thickness measurement system as claimed in claim 10, wherein the plurality of characteristics further includes at least one of a warpage, a stress, a doping concentration, an optical coefficient, and an electrical coefficient for each of the plurality of interface layers.

15. The thin film thickness measurement system as claimed in claim 10, wherein the material of the test object is selected from at least one of a compound, an insulator, a semiconductor, and a metal.

16. The thin film thickness measurement system as claimed in claim 10, wherein the object to be measured is a semiconductor wafer, the plurality of interface layers include an epitaxial layer and a substrate, and the plurality of characteristics include the thickness of the epitaxial layer.

17. The thin film thickness measurement system as claimed in claim 10, wherein the test object is a semiconductor package structure, the plurality of interface layers include a protective layer, an insulating layer, a conductive layer, a substrate and a wafer, and the plurality of characteristics include the thickness of the protective layer.

18. The thin film thickness measurement system as claimed in claim 10, wherein the test object is a printed circuit board, the plurality of interface layers include a copper clad laminate, a half-cured sheet, a copper foil, a solder resist layer and a character layer, and the plurality of characteristics include the thickness of the solder resist layer.

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