Functional Materials for Advanced Patterning Robert D. Allen. IBM Almaden Research Center

Transcription

1 Functional Materials for Advanced Patterning Robert D. Allen Business Unit or Product Name IBM Almaden Research Center 2003 IBM Corporation

2 Resists/Materials for Advanced Patterning Trends in Lithography and Materials Implications Chemical Amplification----unlocking the potential of lithography through materials and chemistry 193nm Lithography---materials challenges, amazing etendibility Immersion Etending Immersion (time permitting) High Inde Double Patterning Post-immersion lithography candidates EUV EB Nanoimprint The Potential of Lithography-directed Self Assembly Bob Allen - DISKCN

3 CA Resist Basics History of Chemically Amplified (CA) Resists Ito, Willson and Frechet (IBM San Jose) invented CA resists in the early 1980s. Initial focus was on very high speed resists for DUV (254nm lamp-based scanners). TBC resist was generation 1 (ca. 1984) First manufacturing in IBM for 4 Mb DRAM in mid 1980s IBM developed 2 nd generation positive resists (APEX, APEX-E). Still in use today! (World-wide adoption for 0.25 micron lithography) Several Generations of DUV Lithography followed (thanks to IBM s ESCAP) (1990 s) led to acceleration of Moore s law) 193nm resists followed (IBM/Fujitsu) (late 90 s) Etension of 193nm via Immersion lithography (now!) What is net? Bob Allen - DISKCN

4 CA Resist Basics Chemistry of Chemically Amplified Resists revolutionary change! + S X - hν H + X - epose post-epose bake H + ( CH -CH ) 2 heat + + deprotection + C 2 + H + products nonpolar ( CH -CH ) 2 H polar develop Bob Allen - DISKCN

5 Functional Polymers for Patterning ESCAP the prototype in functional materials design y y z Hiroshi Ito IBM Fellow H Dissolution control Adhesion etch resistance high Tg H Property control knob CA switching group Acrylic Ester/Phenolic Resist: A breakthrough in resist design Similar design concepts practiced in 193nm litho, EUV, EB Bob Allen - DISKCN

6 193nm Lithography Materials Alicyclic Acrylic Polymers (nonphenolic) Etch resistance and development properties were difficult to achieve Eplosion in High Performance Materials and processes helped to etend 193nm lithography to sub-40nm HP resolution. Materials hybridized from 157nm and DUV lithography helped enable immersion lithography R n F 3 C CF 3 H Bob Allen - DISKCN

7 Immersion Materials Resist/topcoat/fluid interfaces in I-lithography bottom element water Evaporation temp, precip air permeation particles bubbles surface energy amine contamination resist component etraction topcoat resist intermiing BARC substrate Many interfaces, all important, some more than others! Bob Allen - DISKCN

8 Base-soluble Topcoat Solutions beyond conventional topcoats Graded Topcoat* surface-active additive in topcoat Topcoat-free Resist surface-active additive in resist Topcoat-free Resist modified resist + low-leaching PAG Benefits Performance Resist Wafer Low etraction Moderate RCA Good performance Well established Low etraction Moderate-High RCA Higher CAs possible Lower fluorine content (less epensive) Low etraction Very high RCA Fewer process steps Very high RCAs No need to modify resist Etraction dependent upon PAG design Moderate RCA Fewer process steps nly one material Limitations Receding CA limited by acidic groups Etra process steps Receding CA limited by acidic groups Etra process steps Additive design crucial for low defectivity Uses specialized PAGs Modify resist to increase RCA Bob Allen - DISKCN * Same Concept as IBM s Graded BARC

9 Additive approach is more effective in topcoat-free resists Graded topcoat Topcoat-free resist Topcoat Resist Wafer Must dissolve 100+ nm Need many acidic groups for dissolution Increase hysteresis Lower receding contact angle Must dissolve ~2 nm of material Can rely on underlying photoacid to Generate acidic groups where needed After PEB! hν R f y R f y H + R f H y F 3 C CF 3 H Sanders et al. Proc. SPIE, Bob Allen - DISKCN Hydrophobic Acidic group for dissolution (eposed regions)

10 HFA groups can increase developer wetting y y R R acid-labile F 3 C CF 3 R acid-labile F 3 C CF 3 H Tilting drop contact angles With fluoroalcohol groups No fluoroalcohol groups water θ rec θ adv 0.26 N TMAH Sanders, Microlithography World, Fluoroalcohol groups increase hysteresis the least amongst acidic groups Bob Allen - DISKCN

11 Potential Successors to 193nm lithography EUV Tooling challenges, high speed resists required Sensitivity, Resolution and LER need to be achieved simultaneously EB Tooling challenges, high speed resists required Sensitivity, Resolution and LER need to be achieved simultaneously Imprint Tooling challenges, template challenges Throughput, defectivity, learning required Bob Allen - DISKCN

12 Directed Polymer Self-assembly (DSA) Definition: Use lithographically defined prepatterns to directed polymer self-assembly Lithographically defined prepatterns Polymer self-assembly Chemical patterns + Topographical patterns Well-defined dimension. Self-healing. Compatible with current litho tooling Challenges: Develop materials and process for litho-friendly directed self-assembly Bob Allen - DISKCN

13 Integration Materials an eample of litho-friendly integration materials DSA Methods Tripling Quadrupling P resist = 85 nm P resist = 115 nm y crosslinkable group Provide interface between SA and litho materials Compatible with standard litho process and materials J. Y. Cheng, D. P. Sanders, H. -C. Kim, L. K. Sundberg, SPIE Proceeding, 6921, (2008) P SA = 28.3 nm P SA = 28.8 nm Self-assembly Materials Materials for scaling Materials for clean up (self-healing) Bob Allen - DISKCN

14 IBM Research Poorly-defined Resist self assembly and self healing Well-defined Frequency doubled Self-assembled patterns 200 nm Defect-free directed self-assembly (hp=14.4nm) on ill-defined resist patterns (hp=28.8nm) J. Y. Cheng, C. T. Rettner, D. P. Sanders, H. -C. Kim, W. D. Hinsberg, Adv. Mater. 2008, 20, Bob Allen - DISKCN