1. Speaker: Hao-Wen Chuang ( 莊浩彣 ) Advisor: Assistant Prof. Chung-Hao Tien Assistant Prof. Yi-Pai Huang Display Institute, National Chiao Tung University, Hsinchu, Taiwan Jul, 07 2008 光學元件精密製造與檢測 第十三章 薄膜品質檢測 13.10~13.13 國家實驗研究院 儀器科技研究中心

2. 2 Advanced Display Optics Lab  Hardness & Adhesion  Environmental Test of Optical Thin Films - defect - scratch & dig - mechanical stability - temperature - chemical and radiation  Electrical resistivity  Laser Damage Outline

3. 3 Advanced Display Optics Lab 13.10.1 Hardness – Nanoindenter ( 奈米壓痕器 ) plastic deformation elastic deformation reduced modulus ( 變形模數 ) E r specimenindenter Most cases initial unloading stiffness ( 初始卸載剛性 ) A: projected area of the elastic contact E: elastic modulus( 彈性模數 )

4. 4 Advanced Display Optics Lab Nanoindenter (conti.) hardness total displacement h c : contact depth indenter area function Assume specimen and load frame are two series springs, total measured compliance ( 總測 量柔軟性 ) curve fitting…  

5. 5 Advanced Display Optics Lab 13.10.2 Adhesion Test  Pull-off( 拉拔 ) & Topple( 推拉 ) forcetorque  Acceleration centrifugal ultrasonic N: critical angular velocity r: radius ρ: density d: thickness σ: tension ρ c : density d: thickness a: amplitude Suitable for thickness > 10um

6. 6 Advanced Display Optics Lab 13.10.2 Adhesion Test (conti.)  Shock-wave compressive shock wave: substrate  waveguide  film tensile shock wave: film  waveguide  substrate  Shear( 剪力 )

7. 7 Advanced Display Optics Lab  Hardness & Adhesion  Environmental Test of Optical Thin Films - defect - scratch & dig - mechanical stability - temperature - chemical and radiation  Electrical resistivity  Laser Damage Outline

8. 8 Advanced Display Optics Lab Defect

9. 9 Advanced Display Optics Lab Scratch( 刮傷 ) & dig( 刺孔 ) Scratch/dig: SC/DG scratch: width in μm dig: diameter in 0.01mm 刮傷檢驗規範： 1. 鏡片通光孔徑內不容許有任何大於標準之刮傷存在。 2. 存在於圓形鏡片兩面之標準刮傷之總和長度，不可大於鏡片直徑之 1/4 。 3.Max combined lengths of scratches J=(N 1 xL 1 /D)+(N 2 xL 2 /D) 刺孔檢驗規範： 1. 鏡片通光孔徑內不容許有任何大於標準之刺孔存在。 2. 在直徑 20mm 圓面積內，僅容許一顆標準刺孔存在。 3. 在直徑 20mm 圓面積內，所有刺孔的刺孔直徑總和不得大於標準刺孔直徑的 2 倍。 4. 直徑小於 2.5um 之刺孔忽略不計。 5. 刺孔檢驗以鏡片之個別鏡面為檢驗單位，任一鏡面皆須符合上述一至三項規範。 double surface with scratches only single surface with scratches

10. 10 Advanced Display Optics Lab Mechanical Stability Test  Abrasion( 抗擦性 )  Adhesion( 附著性 )  Solubility( 溶解度 )

11. 11 Advanced Display Optics Lab Temperature Test

12. 12 Advanced Display Optics Lab Chemical and Radiation Test

13. 13 Advanced Display Optics Lab  Hardness & Adhesion  Environmental Test of Optical Thin Films - defect - scratch & dig - mechanical stability - temperature - chemical and radiation  Electrical resistivity  Laser Damage Outline

14. 14 Advanced Display Optics Lab Hall Effect Measurement System  carrier mobility, carrier concentration, resistivity  1879, Edwin H.Hall FEFE J: current density n: carrier concentration drift velocity Hall voltage Hall coefficient  n: electron concentration p: hole concentration μ: Hall mobility q:charge Electrical resistivity

15. 15 Advanced Display Optics Lab Four-point Probe Measurement R C : contact resistivity R SP : spreading resistivity Error high resistance voltmeter R C,R SP neglected R sheet : Ω/ □ T f : thickness c.f.: correction factor

16. 16 Advanced Display Optics Lab  Hardness & Adhesion  Environmental Test of Optical Thin Films - defect - scratch & dig - mechanical stability - temperature - chemical and radiation  Electrical resistivity  Laser Damage Outline

17. 17 Advanced Display Optics Lab 13.13 Laser Damage  High power laser cause laser damage on optical film.  Laser damage mechanism - particle inclusion and defect  thermal absorption - optical absorption of material  e - : from valence band to conduction band  Laser-Induced Damage Threshold (LIDT) ( 雷射破壞閥值 ) - Firing a laser at a test sample until the surface is damaged. (1) single shot: use only one single shot on each unexposed site (2) multiple shot: use multiple shots in the same location - LIDT: multiple shot > single shot because of defects reduced after laser annealing

18. 18 Advanced Display Optics Lab Laser Damage Measurement optical properties change acoustic wave changes refractive index of air  He-Ne laser deflection

19. 19 Advanced Display Optics Lab Summary Nanoindenter measures the hardness of thin film. Adhesion of thin film can be measured by pull-off, topple, acceleration, shock-wave, and shear methods. Optical thin films should pass several environmental tests, including defects, scratch, dig, mechanical stability, temperature, chemical, and radiation. Electrical resistivity can be measured by Hall effect or four-point probe measurement system. The issue of laser damage resulting from high power laser should be considered.

20. 20 Advanced Display Optics Lab 20 hwchuang.di96g@g2.nctu.edu.tw

21. 21 Advanced Display Optics Lab 片電阻 d d

22. 22 Advanced Display Optics Lab (1) EI (electron impact) ( 電子撞擊 ) e - : from valence band to conduction band (2) MPI (multi-photon ionization) ( 多光子電離 ) TI (tunnel ionization) ( 穿隧電離 ) - nonlinear optical absorption (high freq. laser) - electron pass through potential barrier (intense electric field) (3) Avalanche ionization ( 崩裂電離 ) high electron concentration conduction band  dielectric breakdown