Progress in EUV resist development

Transcription

1 Progress in EUV resist development T. Shimokawa, T. Kai, D. Shimizu, K. Maruyama, A. Saitou, Y. Hishiro, Semiconductor Materials Laboratory, JSR Corporation. JSR Micro, INC International Workshop on EUV Lithography June. 12, 2008 EUV Workshop / June. 12,

2 Contents Current status and issues of EUV resist Material development Molecular glass (Noria) High acid generation resin Summary EUV Workshop / June. 12,

3 EUV exposure result (Polymer-type) Resist Character Exposure result 30nmL/S 28nmL/S 26nmL/S A PHS resin TPS PAG 24mJ LWR 7.7nm 24mJ LWR 6.7nm 24mJ LWR 7.1nm Resolution limit: 26nmL/S, LWR@ 50nmL/S = 5.9nm (Evaluation Condition) MET at LBNL, on-bare-si, FT:70 nm, SB 130C-60s, PEB 130C-60s, development time 60s. Resist A (PHS resin and TPS PAG) resolved 26 nm L/S patterns. EUV Workshop / June. 12,

4 Evaluation results of EUV resist Performance Resist A Character Base PHS Polymer TPS PAG Resist requirement (ITRS 2007) Type CAR Resolution (1:1 L/S) 26 nm (resolution limit) 32 nm (with Process Margin) Sensitivity 24 mj/cm mj/cm 2 LWR-3 (Low frequency) 6.7 LS 1.7 nm Outgas molecules/cm molecules/cm 2* EL LS - DOF LS - *:SEMATECH s spec for microexposure tool For 32nmhp and beyond, sensitivity, LWR and resolution are needed further improvement. Additionally, outgass must be decreased. The acceleration of novel material development is needed. EUV Workshop / June. 12,

5 Contents Current status and issues of EUV resist Material development Molecular glass (Noria) High acid generation resin Summary EUV Workshop / June. 12,

6 Issue LWR Resolution Main effect Material development Novel material 1.Molecular glass 2. Polymer bound PAG with anion pendant type 3.Bulky protecting group Concept Smaller molecule Size Smaller grain size Homogeneity Acid diffusion control Volatile control from resin Sensitivity 4.Photo-destructive base 5.High acid generation resin Acid diffusion control Higher acid amount Outgas 6.High quantum yield PAG with bulky structure Higher acid amount Volatile control from PAG Status of molecular glass and high acid generation resin are reported. EUV Workshop / June. 12,

7 Image figure Concept of molecular resist Resolution improvement exposure Large grain(ca.20nm PHS) Small Grain (low molecular?) Dev. Dev. Large grain size Poor resolution Small grain size High resolution LWR improvement exposure Large Grain(ca.20nm PHS) Small Grain (low molecular?) Dev. Dev. Large grain size Large LWR Small grain size Small LWR EUV Workshop / June. 12,

8 Noria 1) Resorcinol + Character Small molecular size ca.2nm C-(CH 2 ) 3 -C Glutaraldehyde (1,5-Pentanedial) HCl 80 o C, 48 h in Ethanol Noria 83% Yield More rigid structure than other molecular glass It is possible to introduce various protecting group etc. Noria was selected as molecular glass for our molecule resist. Higher thermal stability than other molecular glass 1) Nishikubo et al., Angew. Chem. Int. Ed. 2006, 45, EUV Workshop / June. 12,

9 Physical property Noria - Physical property 1- PHS resin Noria Molecular weight (Mw) Approx Approx.2000 Polydispersity > Thermal stability 180 Tg >300 weight loss) Molecular size*(calculation) Approx.7 nm Approx.2 nm Grain size** Approx.17 nm Approx.13 nm Surface roughness*** Approx.14nm Approx.10nm 80 EUV Workshop / June. 12, In collaboration with Prof. Nishikubo Kanawagwa Univ. *Calculation method: MD, **Grain size was obtained from AFM image about protected PHS resin only and protected Noria only after coating, ***Surface roughness was obtained from AFM image about resist comprising of protected Noria and protected resin after half exposure. Noria showed smaller molecular size, grain size and surface roughness than that of PHS resin. Noria has high thermal stability.

10 Noria - Physical property 2- In collaboration with Prof. Nishikubo Kanawagwa Univ. Physical property Other molecular glass R 2 : H or protecting group Protected Noria O 1 R R : H or 1 OR 1 protecting group Distribution of protecting ratio Existence ratio(%) Wide Existence ratio(%) Narrow Protecting ratio(%)* Protecting ratio(%)** Protected Noria showed narrower distribution of protecting ratio than that of other molecular glass. EUV Workshop / June. 12,

11 Exposure Result (Resolution) EUVL 28nmL/S 26nmL/S 33mJ 33mJ 24nmL/S Resist B O 1 R 3 S TPS salt X 33mJ R 1 : H or protecting group Protected-Noria (Evaluation Condition) MET at LBNL, on-barc, FT:70 nm, SB 140C-90s, PEB 130C-90s, development time 60s. Resist B showed good resolution. EUV Workshop / June. 12,

12 EUVL Exposure Result (ELBOW) Resist B O 1 R R 1 : H or protecting group Protected-Noria 3 S X TPS salt 50 nm Elbow pattern (Evaluation Condition) MET at LBNL, on-barc, FT:70 nm, SB 140C-90s, PEB 130C-90s, development time 60s. EUV Workshop / June. 12,

13 Exposure Result (LWR) EUVL Resist B 50nmL/S LWR=5.6nm 40nmL/S LWR=6.4nm O 1 R R 1 : H or protecting group 33mJ 33mJ Protected-Noria 32nmL/S LWR=6.3nm 28nmL/S LWR=6.1nm 3 S X TPS salt 33mJ 33mJ (Evaluation Condition) MET at LBNL,on-BARC, FT:70 nm, SB 140C-90s, PEB 130C-90s, development time 60s. LWR of resist B at 28nm L/S pattern was 6.1 nm. EUV Workshop / June. 12,

14 Litho performance of molecular resist applied Noria Performance Resist A Resist B Character Base PHS Polymer TPS PAG Noria (molecular glass) TPS PAG Resist requirement (ITRS 2007) Type CAR CAR Resolution (1:1 L/S) 26 nm (resolution limit) 28 nm (resolution limit) <26 nm (pattern collapse) 32 nm (with Process Margin) Sensitivity 24 mj/cm mj/cm mj/cm 2 LWR-3 (Low frequency) 6.7 LS 6.1 LS 1.7 nm Noria showed comparable litho performance to PHS resin. EUV Workshop / June. 12,

15 Molecular glass - Future Action - 1. Formulation optimization of Noria 2. Molecular glass with PAG Current system New system PAG Molecular glass PAG Molecular glass Each components exists separately PAG is integrated into Molecular glass Optimization of formulation is ongoing. Molecular glass with PAG is under development. EUV Workshop / June. 12,

16 Contents Current status and issues of EUV resist Material development Molecular glass (Noria) High acid generation resin Summary EUV Workshop / June. 12,

17 2. High acid generation resin Acid generation mechanism To improve sensitivity EUV Amount of secondary 1. X electron is increased by X + e * high absorption unit + x X is high absorption unit e - + AG A + G - Increasing reaction rate of secondary electron with AG High acid generation resin 3. + G HG + HS unit is good unit for proton supply Development status of high acid generation resin is reported. AG: Acid Generator A: Decomposed fragment of AG, G - : Counter Anion of AG EUV Workshop / June. 12,

18 High Absorption Photoabsorption cross sections μ (cm 2 /mol) H Absorption of EUV N C F Si Atomic Number S 1) Proc. SPIE. 3997, P.588, ) Atomic Data and Nuclear Data tables. 54(2), P.181, To increase absorption, N, O and F are available candidates Element Advantage Disadvantage O and F was selected as available candidates N 1.None 1.Act as quencher O 1.Less reactivity with electron 1.Etching resistance Development status of F rich resin is reported. F 1.High absorption 1.High reactivity with electron 2. Outgassing (HF?) 3.Etching resistance EUV Workshop / June. 12,

19 Resin into which F is incorporated PHS Resin=100 Ref HS/monomer with F =75/25 Sample Resin Funit HS/monomer with F =50/50 FT:100nm Composition PHS Ref =100 HS/monomer with F=75/25 HS/monomer with F=50/50 HS PAG TPS-Tf Amount of generated Ref 20%UP 25%UP Measured at Osaka university Under 100nm FT, amount of generated acid increased with increasing ratio of fluorinated monomer. Litho performance is being evaluated. Additionally, O rich resin is being prepared. EUV Workshop / June. 12,

20 Contents Current status and issues of EUV resist Material development Molecular glass (Noria) High acid generation resin Summary EUV Workshop / June. 12,

21 Summary Current status and issues of EUV resist For 32nmhp and beyond, sensitivity, LWR and resolution are needed further improvement. Additionally, outgass must be decreased. The acceleration of novel material development is needed. Material development to improve resolution and LWR Molecular glass Noria Noria showed smaller molecular size, grain size and surface roughness than that of PHS resin. Noria showed high thermal stability. Protected Noria showed narrower distribution of protecting ratio than that of other molecular glass. Noria showed comparable litho performance to PHS resin. Material development to improve sensitivity High acid generation resin Under 100nm FT, amount of generated acid increased with increasing ratio of fluorinated monomer. EUV Workshop / June. 12,