Progresses in NIL Template Fabrication Naoya Hayashi

Transcription

1 Progresses in NIL Template Fabrication Naoya Hayashi Electronic Device Operations Dai Nippon Printing Co., Ltd.

2 Contents 1. Introduction Motivation NIL mask fabrication process 2. NIL mask resolution improvement 100keV EB writing results 50keV EB writing results 3. NIL mask metrology results 4. Imprinted pattern results 5. Summary 1

3 Motivation for Nanoimprint mask development Nanoimprint lithography is counted as a litho solution candidate of hp32nm and below. But has potential issue in: 1) Defect control (both in wafer process and mask) 2) Overlay 3) Throughput Recently, cross point memories are expected to be a reasonable candidate for nanoimprint utilization. 1) Requires extremely fine pattern 2) Defect and overlay requirements may be relaxed Our current highest priority in mask development is on the resolution improvement. 2

4 Nano-imprint mask process flow Electron beam Resist Chrome Quartz Exposure Development Chrome etching Resist stripping Quartz etching Chrome stripping Quartz template!! For high resolution pattern making In material, thinner Chrome and resist is used. In Process, high performance EB machine usage and process optimization are evaluated. 3

5 Tools and Materials Exposure tool 100keV spot beam EB writer (JBX9300, ELS-7000) 50keV VSB EB writer (4X photomask manufacturing tool) Resist materials Non CAR (Positive tone) Measurements tool CD-SEM (LWM9000) Image placement measurement (LMS IPRO) Cross section-sem (Ultra) Imprint tool Imprio 250 4

6 Template resolution images with 100keV EB writer (Dense line) Chrome images after quartz etching Magnification: 150k Quartz images (cross sectional view) No picture hp32nm hp24nm hp22nm hp20nm hp18nm hp16nm 5

7 Resist images Template resolution images with 100keV EB writer (Hole) Magnification: 150k Chrome images after quartz etching hp32nm hp28nm hp24nm hp22nm hp20nm Cross sectional images 6

8 Resist images Template resolution images with 100keV EB writer (Dot) Magnification: 150k Chrome images after quartz etching Not resolved hp32nm hp28nm hp26nm hp24nm hp22nm Cross sectional images 7

9 Next trial Exposure condition and resist optimization Resist images (top view) Magnification: 300k Resist images (cross sectional view) hp16nm hp15nm hp14nm hp13nm 8

10 hp 15nm Dense line Chrome images after quartz etching (top) Magnification: 300k hp15nm 9

11 EB writing time calculation Temporary hp32nm full field chip Data area: 33 x 26mm Condition Writing data for positive resist (non CAR) kev SB: 1month 50keV VSB: 12h 0 50keV VSB 100keV Spot Beam 10

12 Template resolution images with 50keV EB writer Chrome images after quartz etching (Dense line) Magnification: 150k Chrome images after quartz etching (Hole) hp44nm hp40nm hp36nm hp32nm hp28nm 11

13 Template pattern images with 50keV EB writer SRAM pattern Magnification: 75k CMOS Litho Test Patterns hp44nm hp40nm hp36nm hp32nm 12

14 CD uniformity results on templates 50keV 100keV Area 20X20mm (6X6 arrays) hp 32 nm dense line Area 30X24mm (6X5 arrays) hp 32 nm dense line Average : 27.5 nm Range : 5.0 nm 3s : 3.2 nm Average : 29.9 nm Range : 1.3 nm 3s : 1.2 nm 13

15 LER results of 32nmHP patterns on Templates 50keV 100keV Magnification: 150k CD : 30.2 nm LER 3s : 4.3 nm CD : 32.8 nm LER 3s : 2.9 nm * Average : 10 lines Box length : 700nm 14

16 [mm] keV Registration results across the field Area 28X24mm (5X3 arrays) hp 32 nm dense line X Y 3s : 6.0 nm 6.0 nm Min : -4.0 nm -4.0 nm Max : 3.0 nm 4.0 nm [mm] [mm] keV Area 30X24mm (4X3 arrays) hp 32 nm dense line [mm] X Y 3s : 6.0 nm 6.0 nm Min : -2.0 nm -3.0 nm Max : 4.0 nm 4.0 nm 15

17 AFM measurements trial Tool:InSight 3DAFM ((Veeco Instruments Inc.) Measurement mode :Enhanced DT mode SEM profile AFM profile hp32nm Space 31.9nm hp28nm CDP15-150C High density Carbon Space 27.3nm hp24nm Space 21.9nm *SEM Measurement CD 16

18 Imprint results using template by 100keV EB Writer 32nm 22nm Parameter mean standard deviation Line width LWR 3σ Pitch LER 3σ Parameter mean standard deviation Line width LWR 3σ Pitch LER 3σ [nm] 17

19 32nm Imprint LER measurements using template by 50keV EB Writer 35nm Parameter mean standard deviation Line width LWR 3σ Pitch LER 3σ Parameter mean standard deviation Line width LWR 3σ Pitch LER 3σ [nm] 18

20 Comparison with EUVL ~LER of 32nmHP 19

21 Initial trial for full field mask making Presented at SPIE Advanced Lithography 2008 by Samsung. Imprint by Molecular Imprints. 20

22 Recent Imprinted Results 32nm half pitch r 21

23 Recent Imprinted Results 32nm half pitch 22

24 Recent Imprinted Results 28nm half pitch Mag =15k Mag = 50k Mag = 50k 23

25 Summary NIL mask process with a 100keV spot beam EB and 50keV VSB EB were developed and masks are delivered for evaluation including full chip application. Resolution of the NIL mask manufacturing process for both process were confirmed. 100keV process shows hp16nm resolution for line and spaces on resist, and promising preliminary results for final etched quartz patterns. 50keV process shows hp32nm resolution, potential down to 2x nm, and acceptable writing speed. CD uniformity, pattern roughness, and registration results were acceptable for NIL process development masks. Initial imprint showed good printability. Future works : Defect inspection & Repair 24

26 Acknowledgement We would like to thank MII people (Molecular Imprints, Inc.) for sharing imprint results. We would like to thank Sean Hand, Max Ho, and Marc Osborn (Veeco Instruments Inc.). We also express our thanks to DNP members involved in this work and Electronic Materials Research Department members. Photomask Japan