Perpendicular Media - Metrology and Inspection Challenges. Sri Venkataram KLA-Tencor Corporation Sept 19, 2007

Transcription

1 Perpendicular Media - Metrology and Inspection Challenges Sri Venkataram KLA-Tencor Corporation Sept 19, 2007

2 Agenda Perpendicular Media Adoption PMR Metrology & Inspection Implementation Solutions Review Summary

3 Perpendicular Media Adoption PMR Media In CQ207 over 33% of all finished media was PMR compared to 20% in CQ107 Seagate and HGST are leading the pack By the end of CY07 PMR-based media should surpass LMR-based media With PMR, companies continue to reach new areal density points Substrates In CY07 Glass volumes will account for over 33% of the total substrate market With continued growth in 2.5 HDD, glass volumes will grow even stronger source: TrendFocus CQ207 media quarterly report

4 PMR Metrology & Inspection Implementation Challenges Implications New Writer Head CDs and Shape metrology Micro defect inspection on heads Tighter Head-Disk Interface Thermal fly-height control Circ & Radial Disk Topography New Magnetic Media Soft-under layer monitoring Recording layer magnetics Texture & Polish Uniformity Shrinking Bit Size & Narrower Track Pitch Micro defect inspection on media Improved NRRO metrology

5 Solutions Review Production Critical NRRO control Fly height control Defect control Topography control Magnetics control Solutions Requirements Critical to production - results have to provide a competitive advantage Technology is unique - differentiated with high value add Cost effective mature market with limited investment potential Complexity of Solution

6 Magnetics Control SUL and Recording layers Correlation to VSM

7 PMR Media and Performance Parameters PMR media enables a path to higher areal density Production media parameters require tighter control perpendicular coercivity, Hc nucleation field, Hn remanent coercivity, Hr remanent magnetization thickness, MrT coercivity squareness, S Above parameters affect recording performance metrics half-amplitude pulse width, PW50 overwrite, OW signal-to-noise ratio, SNR modulation level Without adequate production monitoring, recording media reliability is compromised

8 PMR Media Process & Magnetics Control Glass Substrate Polish Wash Mechanical Texture Final Wash Polish Sputter Lube Final Tape Burnish Glide and Certify Test Media Finished Aluminum Substrate KerrMapper Polar Kerr DiskMapper M3 Glas s Sub strat e P oli sh W a s h Alu min um Sub strat e SUL Magnetics Field Related Magnetics Magnetic Thickness Control Hc and Skew Hc, Hn and Hr MrT, Hr and Hnr

9 Magnetic Thickness - MrT, Production Control Critical to production Unique technology Cost effective Sputter Tool Uniformity Fast and Detailed : 32 sector, 0.5 sec/remanence loop, simultaneous dual sided mapping Extendibility : High field capability up to 1.5T Performance : Non destructive, +/- 1% MrT precision spec with SUL across a single track CoO: compared to any other technique, lowest cost/disk; automated handling for ease of use

10 Mrt Measurement Capability Performance Independent of SUL Thickness MrT measurement with SUL Matrix M3 correctly shows independence of MrT to SUL VSM incorrectly shows Mrt increasing with SUL M3 MrT measurement Repeatability 3 sigma/mean < 1% Unbeatable, non-destructive technique

11 Correlation of DiskMapper M3 to VSM Feature MrT Independence from SUL Effects DiskMapper M3 Proven technique not influenced by SUL VSM Influenced by SUL Max Applied Field > 1.5 T Double sided, no-contact, full disk measurement Not capable Automated Cassette Handling Designed for in-line processing FA only Measurement Time 0.5 sec/loop 600 sec/loop MrT Absolute Calibration Correlates Reference Tool TOTAL (R=0, Y=1, G=2) 11/12 4/12 Excellent Correlation to VSM Over a Wide Range Non-destructive and Fast FA vs. Production Monitoring Data and Time to Results are a competitive edge!

12 Topography Control Correlation to AFM Bare Glass Topography Head Disk Interface Analysis Media QA

13 PMR Media Process &Topography Control Glass Substrate Polish Wash Mechanical Texture Final Wash Polish Sputter Lube Final Tape Burnish Glide and Certify Test Media Finished Aluminum Substrate Critical to production Unique technology Cost effective Candela 6300 Series Topography and Defect Control Micro and Nano RMS Defect Classification

14 Correlation to AFM: Bare Glass Substrate The Candela 6300 Micro-RMS application correlates well with AFM roughness (R² > 0.90) Micro-RMS v. AFM RMS The correlation curve to the right is only slope corrected showing sub-ångström sensitivity Similar correlation has been determined with pre-sputter metal substrates AFM RMS ~ 0.70 Å AFM RMS ~ 5.30 Å Candela Micro -RMS (Å) sub-ångström sensitivity y = 1.00x R 2 = 0.96 Transparent Glass Substrate AFM RMS (Å) Note: Micro-RMS analysis bandwidth set to 20 to 100 µm AFM scan area is 5 x 5 µm with 256 lines per scan

15 Bare Glass Micro Roughness Disk 1-SZc-R Disk 2-SZc-R Disk 3-SZc-R High Circumferential Roughness Low Disk 1-SZc-C Disk 2-SZc-C Disk 3-SZc-C What Roughness is Appropriate? High Radial Roughness Low

16 Head Disk Interface Analysis Topography correlated to Low Frequency FH Failures PMR has driven HDI to lower levels, implying that it is now more critical to control lower roughness and waviness substrates Using Power Spectral Density analysis, topography can be determined over wide spatial wavelengths Micro-RMS (Å) Micro-RMS Radial Topography μm μm μm increasing radial waviness with FH failure level In this case, Radial Micro- RMS at frequencies above 300 µm shows increasing trend with FH failure level Disk 01A Disk 01B Disk 02A Disk 02B Disk 01A Disk 01B Disk 02A Disk 02B Disk 01A Disk 01B Disk 02A Disk 02B Group 1 Group 2 Group 3

17 Media Quality Assurance Topography correlated to End-of-Line Failures Average Cir Nano- RMS = 1.98 Å Average Rad Nano- RMS = 5.25 Å Average Total Nano- RMS = 5.55 Å Average Bias Nano- RMS = 0.50 Å Similar avg. RMS values! But Average Cir Nano- RMS = 1.89 Å Average Rad Nano- RMS = 5.68 Å Average Total Nano- RMS = 5.96 Å Average Bias Nano- RMS = 0.60 Å Analyzing the RMS distribution histograms (skewness and kurtosis) show the precise characteristics of the disks correlating to QA Metrics

18 Defect Inspection Contamination Shrinking Bit Size BPM

19 Contamination and Defect Control Multiple process points for multiple defect types Glass Substrate Polish Wash Mechanical Texture Final Wash Polish Sputter Lube Final Tape Burnish Glide and Certify Test Media Finished Aluminum Substrate To improve reliability and reduce contamination, allowable particle and defect sizes continue to shrink

20 Shrinking Bit Size: Pits, Bumps and the like Pits : cause exponential decrease in magnetic amplitude Bumps : map thermal asperities at the drive level Height Image Height Image Nano pits and bumps are driving new technology challenges Solutions already exist for the semiconductor market space The challenge is to implement something similar into the mature HDD market

21 BPM Features and Roadmap Production Critical? Unique Technology Cost Effective 10-25nm 50nm Millions of Magnetic Islands X-sectional image Roadmap Challenges The cost of the finished disk will have to remain the same New processes imply new challenges how can this market invest? Targeted dimensions are ahead of semiconductor ITRS roadmap!! Images Reference: HGST, MINT workshop 06

22 Summary PMR Challenges New Writer Head Tighter Head-Disk Interface New Magnetic Media Shrinking Bit Size & Narrower Track Pitch Solutions Requirements Critical to production - results have to provide a competitive advantage Technology is unique - differentiated with high value add Cost effective mature market with limited investment potential