ADDRESSING THE CHALLENGES OF DIRECTED SELF ASSEMBLY IMPLEMENTATION

Transcription

1 ADDRESSING THE CHALLENGES OF DIRECTED SELF ASSEMBLY IMPLEMENTATION ROEL GRONHEID, IVAN POLLENTIER (IMEC) TODD YOUNKIN (INTEL) MARK SOMERVELL, KATHLEEN NAFUS, JOSH HOOGE, BEN RATHSACK, STEVEN SCHEER (TOKYO ELECTRON) PAULINA RINCON DELGADILLO, PAUL NEALEY (UNIVERSITY OF WISCONSIN) 1

2 OUTLINE IMEC DSA project objectives Grapho-epitaxy results Chemo-epitaxy results Summary 2

3 OBJECTIVE OF DSA WORK AT IMEC Accelerate learning on DSA through: 1. High material flexibility in 300mm R&D environment 2. Access to state-of-the-art tool sets for litho, etch, SEM and defect inspection all under one roof Determine drawbacks and benefits of pre-patterning strategies Grapho vs Chemo-Epitaxy Determine critical parameters for robust patterning in directed self-assembly Required process characteristics, process windows Sensitivities of flows to material properties Success criteria: Resolution and defect density/pattern fidelity 3

4 FLOW FOR FINGERPRINT PATTERNS Coat neutral layer Coat BCP neutral perpendicular orientation non-neutral parallel orientation anneal Easy test to check surface neutrality and BCP periodicity 4

5 DSA FREQUENCY ANALYSER Image with DSA random patterns 1D rotational average of Power Spectrum Smaller 1D-range to fit the peak 2D Power spectrum Peak position and width are calculated 5

6 IMPACT OF IMAGE MAGNIFICATION Magnification does not impact 100k extracted BCP L 0 50k 1350nm 30k 2700nm 28.27nm 4500nm 28.15nm 28.13nm Lower magnification is better for optimal peak fitting Trade-off with image contrast 6

7 GRAPHO-EPITAXY FLOW Coat BARC + neutral layer Pattern guide resist Coat BCP Harden resist anneal dry develop Optimization of resist thickness in pre-pattern proved crucial for good pattern fidelity 7

8 BCP PATTERNING AND PATTERN TRANSFER BCP L 0 =28nm Wafers shipped to TEL/Yamanashi for BCP etch Patterns are transferred successfully; further optimization ongoing imec TEL/Yamanashi Careful analysis on etched samples will be critical in the absence of 3D metrology for BCP patterns 8

9 RESULTS THROUGH PRE-PATTERN DOSE Through focus = -0.26mm 47mJ/cm2 49mJ/cm nm 51mJ/cm nm 53mJ/cm nm 121.8nm 55mJ/cm nm BCP L0=25nm 9

10 RESULTS THROUGH PRE-PATTERN FOCUS Through dose = 51mJ/cm2 NF 120nm NF 90nm NF 60nm NF 30nm NF BCP L0=25nm 10

11 BLOCK CO-POLYMER VARIABILITY BCP materials from Polymer Source that are nominally identical show significant batch-to-batch variability BCP materials from known semiconductor materrial suppliers are now becoming available Need to run quality control (including frequency analysis) 28nm pitch 20nm pitch 11

12 +BCP Pre-pattern As 1X PROGRAMMED PRE-PATTERN DEFECT No Defect 4 nm Protrusion Error 10 nm Protrusion Error 40 nm Protrusion Error Add Image 12

13 8nm PROTRUSION DEFECTS 250nm pitch pre-pattern 13

14 6nm PROTRUSION DEFECTS 250nm pitch pre-pattern 14

15 LIFT-OFF CHEMO-EPITAXY FLOW Pattern resist on BARC Harden resist Lift-off Coat neutral layer Coat BCP anneal 15

16 FT=59nm FT=90nm FILM THICKNESS REDUCTION 90nm pitch pre-pattern BCP L 0 =28nm FT = 40nm BCP 31nm BCP 16

17 UW CHEMO-EPITAXY FLOW Coat mat Pattern resist Coat + graft neutral brush Strip resist Trim + mat etch Rinse Coat BCP anneal 17

18 UW FLOW RESULTS 100nm pitch pre-pattern BCP L 0 =25nm 250kX 100kX 50kX 18

19 GRAPHO- VS CHEMO-EPITAXY Grapho-epitaxy Guiding structures consume surface area Less complex flow High frequency multiplication rate demonstrated CD/pitch determined by BCP bulk domain size (MW) For frequency multiplication small process window for pre-pattern Most suited for contact hole CDU shrink/repair Chemo-epitaxy Guiding structures under final patterns Complex flow Frequency multiplication <4-5X Many options to adjust thermodynamics for process optimization Most suited for frequency multiplication, LWR repair 19

20 SUMMARY Infrastructure to rapidly learn about DSA defectivity is available at imec Process flows for Grapho- and Chemo-epitaxy are available and under further optimization Grapho-epitaxy will target contact hole shrink and CDU repair Chemo-epitaxy will target frequency multiplication and LWR repair Need for 3D metrology to determine BCP profiles 20

21 ACKNOWLEDGMENTS On-site TEL team at imec Eiichi Nishimura and Fumiko Yamashita at TEL/TML TOK JSR AZ Electronic Materials 21