Using Photodiode Direct-Resist Coating Method 3euvlsymposium.lbl.gov/pdf/2016/Poster/P-RE-08.pdf ·...
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EUV Resist Transmittance Measurement Using Photodiode Direct-Resist Coating Method Daiki Mamezaki , Masanori Watanabe, Tetsuo Harada, Takeo Watanabe Center for EUV Lithography, Laboratory of Advanced Science and Technology for Industry, University of Hyogo, Kamigori, Hyogo 678-1205, Japan One of critical issues of EUV lithography is the development of EUV resist which has the high resolution, high sensitivity, and low line-width roughness. Especially, the high sensitivity is strongly required to relax the specification of EUV light power and to maintain the high-lithographic throughput. To achieve the high sensitivity resist, the key factor is employing the high-EUV-absorption metal such as hafnium and zinc for EUV resist. Since the EUV absorption of EUV resist increased and the secondary electron emissions could increase, the resist sensitivity could increase. In order to evaluate the effect of the high absorption material, it is significant to evaluate the EUV absorption coefficient of a resist in high precision. In order to calculate the absorption coefficient of resist material, the precise measurements of the resist thickness and EUV transmittance are required. We have developed a novel transmittance measurement method to evaluate EUV resist absorption using photodiode resist direct-coating method. And the EUV-absorption-coefficient precise measurement was demonstrated at BL10 Beamline of NewSUBARU light source. Previous method of Direct-Resist Coating on a SiN Membrane Resist coated substrate After resist coating 10 mm 2 mm Resist coating area Si Si ３ N 4 membrane 200 nm 2 mm ×2 mm EUV resist The resist was coated on the window area of silicon-nitride membrane by spin-coating. Resist coating method 1000 rpm 2750 rpm The membrane has warped by the stress after resist coating. Problem Transmittance measurement Photodiode Resist coated silicon-nitride membrane EUV light • 0.8 mm×0.1 mm FWHM EUV light beam size The precision of transmittance measurement was affected by non- uniformity of resist thickness. Problem It was difficult to measure EUV resist transmittance in high precision. e - e - e - e - e - e - e - Employing high EUV absorption metal (Hf, Sn,Te…) Secondary electron increase! Light-sensing area Resist Photodiode • Light-sensing area size : 10 mm×10 mm EUV sensitive photodiode (SXUV-100) Sample resist was directly coated on a light-sensing area of the photodiode (PD) by spin-coating. Resist coating method • PD surface is flat and solid. • The beam alignment is much easier the previous method. Advantage point Area size is 25 times lager. After resist coating Average 120 nm Minimum 119.8 nm Maximum 120.4 nm The resist thickness was measured using NanoSpec6100 Resist thickness was evaluated along the center region of the photoactive length within 2.5 mm in four directions. Evaluation area Measurement point Evaluation area ※ Schematic layout of the PD Transmittance measurement ZEP520A 2000rpm 30 s, 180 ℃ 30 s Highly precise measurement of EUV transmittance was achieved. Radial Position (mm) Resist thickness uniformity was 20 times better. Average transmittance 62.2% Average current value of photodiode Before resist coating I 0 = 31.2 nA After resist coating I = 19.4 nA Photodiode current were measured along this line. ※ Schematic layout of the PD • Thickness : 200 nm • Window area : 2 mm×2 mm • Substrate size : 10 mm×10 mm Silicon-nitride membrane Resist thickness non- uniformity was larger than 10%. Absorption Coefficient -2 -1 0 1 2 3.85 3.90 3.95 4.00 4.05 4.10 Absorption Coefficient (μm -1 ) Non-uniformly < 1% =− Average absorption coefficient 3.96 μm -1 Position (mm) Absorption Coefficient (μm -1 ) μ = Absorption coefficient D = Resist thickness T = Transmittance The precise measurement of absorption coefficient was significantly improved! Conclusion Resist thickness Transmittance The precise measurement of the resist thickness and EUV transmittance are necessary. High precision absorption coefficient We have developed the novel method of resist transmittance measurement using direct-resist coating on the photodiode and the EUV-absorption-coefficient precise measurement was demonstrated at BL10 beamline at NewSUBARU light source. The thickness non-uniformity of resist by spin coating was significantly improved to 0.5%. Thus, the variations of the EUV transmittance and the absorption coefficient were also improved to 0.7% and 1%, respectively. We performed precise EUV absorption- coefficient evaluation using this novel method. This new method will help the development of high sensitive EUV resist with the high-absorption material. After resist coating (Si3N4 membrane) ※ Measurement setup Photodiode x4 NewSUBARU BL-10 EUV mask reflectometer • Beam size : 0.8 mm ×0.1 mm • Wavelength (λ) : 13.5 nm • Resolution (λ/Δλ) : ～1300 Measurement Sample holder Measurement results Resist with metal Direct resist coating ※ Measurement setup using silicon-nitride membrane Bad uniformity Good uniformity Good uniformity Good uniformity It was impossible to calculate the absorption coefficient in high precision. Novel Method of Direct-Resist Coating on a Photodiode Resist coated substrate Introduction
Transcript of Using Photodiode Direct-Resist Coating Method 3euvlsymposium.lbl.gov/pdf/2016/Poster/P-RE-08.pdf ·...
EUV Resist Transmittance Measurement Using Photodiode Direct-Resist Coating Method
Daiki Mamezaki, Masanori Watanabe, Tetsuo Harada, Takeo WatanabeCenter for EUV Lithography, Laboratory of Advanced Science and Technology for Industry,
University of Hyogo, Kamigori, Hyogo 678-1205, Japan
One of critical issues of EUV lithography is the development of EUV resist which has the high resolution,high sensitivity, and low line-width roughness. Especially, the high sensitivity is strongly required to relaxthe specification of EUV light power and to maintain the high-lithographic throughput. To achieve thehigh sensitivity resist, the key factor is employing the high-EUV-absorption metal such as hafnium andzinc for EUV resist. Since the EUV absorption of EUV resist increased and the secondary electronemissions could increase, the resist sensitivity could increase. In order to evaluate the effect of the highabsorption material, it is significant to evaluate the EUV absorption coefficient of a resist in high precision.In order to calculate the absorption coefficient of resist material, the precise measurements of the resistthickness and EUV transmittance are required.
We have developed a novel transmittance measurement method to evaluate EUV resist absorptionusing photodiode resist direct-coating method. And the EUV-absorption-coefficient precise measurementwas demonstrated at BL10 Beamline of NewSUBARU light source.
Previous method of Direct-Resist Coating on a SiN Membrane
Resist coated substrate
After resist coating
10 mm
2 mm
Resist coating area
Si
Si３N4 membrane 200 nm
2 mm ×2 mm
EUV resist
The resist was coated on the window area of silicon-nitride membrane by spin-coating.
Resist coating method
1000 rpm2750 rpmThe membrane has warped bythe stress after resist coating.
Problem
Transmittance measurement
Photodiode
Resist coated silicon-nitride
membrane
EUV light
• 0.8 mm×0.1 mm FWHM
EUV light beam size
The precision of transmittancemeasurement was affected by non-uniformity of resist thickness.
Problem
It was difficult to measure EUV resisttransmittance in high precision.
e-
e-
e-
e-
e-
e-
e-
Employing high EUV absorption
metal (Hf, Sn,Te…)
Secondary electron increase!
Light-sensingarea
Resist
Photodiode
• Light-sensing area size : 10 mm×10 mm
EUV sensitive photodiode (SXUV-100)
Sample resist was directlycoated on a light-sensingarea of the photodiode (PD)by spin-coating.
Resist coating method
• PD surface is flat and solid.• The beam alignment is much
easier the previous method.
Advantage point
Area size is 25 times lager.
After resist coating
Average 120 nm
Minimum 119.8 nm
Maximum 120.4 nm
The resist thickness was measured using NanoSpec6100
Resist thickness was evaluated along thecenter region of the photoactive lengthwithin 2.5 mm in four directions.
Evaluation area
Measurement point
Evaluation area
※ Schematic layout of the PD
Transmittance measurement
ZEP520A 2000rpm 30 s, 180 ℃ 30 s
Highly precise measurement of EUV transmittancewas achieved.
Radial Position (mm)
Resist thickness uniformity was 20 times better.
Average transmittance
62.2%
Average current value of photodiode
Before resist coating I0 = 31.2 nA
After resist coating I = 19.4 nA
Photodiode current were measured along this line.
※ Schematic layout of the PD
• Thickness : 200 nm• Window area : 2 mm×2 mm• Substrate size : 10 mm×10 mm
Silicon-nitride membrane
Resist thickness non-uniformity was largerthan 10%.
Absorption Coefficient
-2 -1 0 1 23.85
3.90
3.95
4.00
4.05
4.10
Abs
orp
tion C
oeff
icie
nt
(μm
-1)
Position (mm)
Non-uniformly < 1%
𝝁 = −𝟏
𝑫𝐥𝐧𝑻
Average absorption coefficient
3.96 μm-1
Position (mm)
Ab
sorp
tio
n C
oe
ffic
ien
t (μ
m-1
)
µ = Absorption coefficient
D = Resist thickness
T = Transmittance
The precise measurement of absorptioncoefficient was significantly improved!Conclusion
Resist thickness
Transmittance
The precise measurement of theresist thickness and EUVtransmittance are necessary.
High precision absorption coefficient
We have developed the novel method of resist transmittance measurement using direct-resist coating on the photodiode and the EUV-absorption-coefficient precisemeasurement was demonstrated at BL10 beamline at NewSUBARU light source. The thickness non-uniformity of resist by spin coating was significantly improved to 0.5%.Thus, the variations of the EUV transmittance and the absorption coefficient were also improved to 0.7% and 1%, respectively. We performed precise EUV absorption-coefficient evaluation using this novel method. This new method will help the development of high sensitive EUV resist with the high-absorption material.
After resist coating
(Si3N4 membrane)
※Measurement setup
Photodiode x4
NewSUBARU BL-10 EUV mask reflectometer
• Beam size : 0.8 mm ×0.1 mm
• Wavelength (λ) : 13.5 nm
• Resolution (λ/Δλ) : ～1300
Measurement
Sample holder
Measurement results
Resist with metal
Direct resist coating
※Measurement setup using
silicon-nitride membrane
Bad uniformity
Good uniformityGood uniformity
Good uniformity
It was impossible to calculate the absorptioncoefficient in high precision.
Novel Method of Direct-Resist Coating on a Photodiode
Resist coated substrate
Introduction
