Inspection method for multilayer semiconductor device

Patent metadata

Field	Value
Publication number	US-11313670-B2
Application number	US-202017037981-A
Country	US
Kind code	B2
Filing date	Sep 30, 2020
Priority date	Sep 30, 2020
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

An inspection method for a multilayer semiconductor device is provided. The inspection method can investigate multilayered ensembles of a multilayer semiconductor device and obtain stratigraphic thickness (ST) maps of each layer in the multilayer semiconductor device by utilizing absorption edges of materials of interests and obtaining calibration quality curves.

First claim

What is claimed is:

1. An inspection method for a multilayer semiconductor device, comprising:
preparing a test sample of the multilayer semiconductor device including:
a test substrate including a test covered portion and a test bare portion; and
a first test layer disposed on the test substrate in the test covered portion, wherein the first test layer is made of a first material of interest;

preparing a plurality of first reference samples, wherein each of the plurality of first reference samples includes:
a first reference substrate having a first covered portion and a first bare portion; and
a first layer disposed on the first reference substrate in the first covered portion, wherein the first layer is made of the first material of interest;

choosing a first region of wavelength corresponding to an absorption edge of the first material of interest;
performing a first calibration process for each of the first reference samples to obtain a plurality of first quality values and a plurality of first thicknesses corresponding to the plurality of first quality values, wherein the first calibration process includes:
measuring a thickness of the first layer as one of the plurality of first thickness;
measuring transmittances of the first covered portion and the first bare portion with a light source emitting lights at the first region of wavelength, to obtain first transmittances of the first covered portion and first bare transmittances of the first bare portion; and
calculating an average ratio of the first transmittances to the first bare transmittances as one of the plurality of first quality values;

applying a linear approximation to obtain a first calibration function of the first thickness according to the plurality of first quality values and the plurality of first thicknesses;
measuring a transmittance of the test bare portion of the test sample, to obtain a test bare transmittance of the test bare portion at the first region of wavelength; and
performing an inspection process for each of a plurality of test points in the test covered portion of the test sample to obtain a plurality of first inspection thicknesses, wherein the inspection process includes:
measuring a transmittance of the test covered portion with the light source emitting lights at the first region of wavelength, to obtain a first test transmittance of the test covered portion;
calculating a ratio of the first test transmittance to the test bare transmittance as a first test quality value;
determining whether the test first quality value within a first predetermined range; and
in response to the first test quality value being determined within the first predetermined range, mapping the first test quality value to the first calibration function to obtain the first thickness corresponding to the first test quality value as one of the first inspection thicknesses.

2. The inspection method according to claim 1 , wherein the first region of wavelength is chosen in a predetermined region less than a minimum wavelength in a transmittance spectrum corresponding to the absorption edge of the first material of interest.

3. The inspection method according to claim 1 , wherein the inspection process further includes:
in response to the first test quality value being determined not within the first predetermined range, measuring transmittances of the test covered portion with the light source emitting lights at wavelengths in a full spectrum, to obtain a transmittance spectrum of the corresponding test point; and
determining whether the absorption edge of the first material of interest absents in the transmittance spectrum,
wherein the first predetermined range is determined according to an average of the plurality of first test quality value.

4. The inspection method according to claim 1 , wherein the test sample of the multilayer semiconductor further includes a second test layer disposed on the first test layer in the test covered portion, wherein the second test layer is made of a second material of interest different from the first material of interest.

5. The inspection method according to claim 4 , further comprising:
measuring transmittances of the test covered portion at wavelengths in a full spectrum, to obtain a transmittance spectrum of the test covered portion; and
determining whether absorption edges of the first material of interest and the second material of interest are clearly distinguishable.

6. The inspection method according to claim 5 , further comprising:
in response to absorption edges of the first material of interest and the second material of interest being determined to be clearly distinguishable, preparing a plurality of second reference samples, wherein each of the plurality of second reference samples includes:
a second reference substrate having a second covered portion and a second bare portion;
a first sublayer disposed on the second reference substrate in the second covered portion, wherein the first sublayer is made of the first material of interest, and the first sublayers of the plurality of second reference samples have same thicknesses, respectively; and
a second sublayer disposed on the first sublayer in the second covered portion, wherein the second sublayer is made of a second material of interest, and the second sublayers of the plurality of second reference samples have different thicknesses, respectively.

7. The inspection method according to claim 6 , further comprising:
choosing a second region of wavelength corresponding to the absorption edge for the second material of interest;
performing a second calibration process for each of the second reference samples to obtain a plurality of second quality values and a plurality of second thicknesses corresponding to the plurality of second quality values, wherein the second calibration process includes:
measuring a thickness of the second sublayer as one of the plurality of second thickness;
measuring transmittances of the second covered portion and the second bare portion with a light source emitting lights at the second region of wavelength, to obtain second transmittances of the second covered portion and second bare transmittances of the second bare portion; and
calculating an average ratio of the second transmittances to the second bare transmittances as one of the plurality of second quality values; and

applying a linear approximation to obtain a second calibration function of the second thickness according to the plurality of second quality values and the plurality of second thicknesses.

8. The inspection method according to claim 7 , wherein the inspection process further includes:
measuring a transmittance with the light source emitting lights at the second region of wavelength, to obtain a second test transmittance of the test covered portion;
calculating a ratio of the second test transmittance to the test bare transmittance as a second test quality value;
determining whether the second test quality value within a second predetermined range; and
in response to the test quality value being determined within the second predetermined range, mapping the second test quality value to the second calibration function to obtain the second thickness corresponding to the second test quality value as one of the second inspection thicknesses.

9. The inspection method according to claim 8 , wherein the first region of wavelength is chosen in a first predetermined region less than a minimum wavelength in a transmittance spectrum corresponding to the absorption edge of the first material of interest, and the second region of wavelength is chosen in a second predetermined region less than a minimum wavelength in a transmittance spectrum corr

Assignees

• Univ Nat Tsing Hua

Inventors

• Pylnev Mikhail
• Wei Tzu-Chien
• Le Duc-Anh

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P74/277

  Circuits for electrically characterising or monitoring manufacturing processes, e.g. circuits in tested chips or circuits in testing wafers · CPC title

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10K85/50

  Organic perovskites; Hybrid organic-inorganic perovskites [HOIP], e.g. CH3NH3PbI3 · CPC title

• H10K30/151

  the wide bandgap semiconductor comprising titanium oxide, e.g. TiO2 · CPC title