Technology

High-speed spectroscopic ellipsometer UNECS series measurement examples

Measurement examples (Repeatability is the standard deviation (1σ) of the results of 10 consecutive measurements.)

1. Organic EL：Alq₃／Glass　Single layer film.

The film thickness and refractive index of four samples are measured. The film thickness is highly correlated with a probe type step profiler.

Sample	A		B		C		D
Target object	Refractive Index	Film Thickness	Refractive Index	Film Thickness	Refractive Index	Film Thickness	Refractive Index	Film Thickness
Target object	N	D(nm)	N	D(nm)	N	D(nm)	N	D(nm)
UNECSmeasurement value	1.712	118.5	1.728	115.8	1.731	115.0	1.729	112.1
Probe type step profiler	－	118.4	－	111.8	－	116.1	－	109.3

2. Thin film solar cell：SiO₂／μc-Si／Glass　Bilayer film.

The SiO₂ thin film of about 20 nm was measured without any problem. The total film thickness (S SiO₂+μc-Si) is highly correlated with a probe type step profiler.

Sample	A			B			C
Measured film	μc-Si	SiO₂	μc-Si+ SiO₂	μc-Si	SiO₂	μc-Si+ SiO₂	μc-Si	SiO₂	μc-Si+ SiO₂
UNECSmeasurement value	509.9	18.2	528.1	523.2	13.8	537.0	518.8	21.7	540.4
Probe type step profiler	－	－	525.4	－	－	541.4	－	－	546.3

3. SiO₂Single layer film.

Even a thin film of about 2 nm has good a reproducibility (repeatability)

	Measured value　*1)	repeatabilityσ
SiO₂film thickness	1.96 nm	0.03 nm

4. Resist Single layer film.（simultaneous measurement of film thickness and refractive index）

Even a thin film of about 2 nm has good a reproducibility (repeatability)

	Measured value　*1)	repeatabilityσ
Resist film thickness (Design film thickness 50 nm)	50.95 nm	0.05 nm
Resist refractive index　*2)	1.576	0.02

5. Resist / BARC　Bilayer film.

	Measured value　*1)	repeatabilityσ
Resist film thickness (Design film thickness 50 nm)	48.17 nm	0.72 nm
BARCfilm thickness (Design film thickness 65nm)	67.16 nm	0.76 nm

6. Resist Three layer film.（simultaneous measurement of film thickness and refractive index）

The film thickness and refractive index of the topcoat(top layer) are measured simultaneously.

	Measured value　*1)	repeatabilityσ
Topcoat film thickness (Design film thickness 30 nm)	28.79 nm	0.05 nm
Topcoat refractive index　*2)	1.342	0.001

7. ALDdeposition　HfO₂ (hafnium oxide) ultra-thin film.

The measured HfO₂ film thickness (5.85 nm, 2.46 nm) near the center of the wafer almost matched with the measured value (6.0 nm, 2.5 nm) by TEM (transmission electron microscope). (The reliability of measurement by UNECS was confirmed.)

【Measurement Model】

	Type of Film.
Top layer	HfO₂
Middle layer	SiO₂
Substrate	Si wafer

【Measurement Result】

Sample	Film Thickness				Film thickness near the center （nm）
Sample	Maximum value （nm）	Minimum value （nm）	Average value （nm）	Uniformity （%）	Film thickness near the center （nm）
5nm Hfo₂/Natural oxide film/Si substrate	6.12	5.63	5.83	4.2%	5.85
2nm Hfo₂/Natural oxide film/Si substrate	2.56	2.37	2.45	3.9%	2.46