Developing an AFM-based Automatic Tool for NanoAsperity Quantification

Transcription

1 Developing an AFM-based Automatic Tool for NanoAsperity Quantification September 18, 2008 Sergey Belikov*, Lin Huang, Jian Shi, Ji Ma, Jianli He, Bob Tench, and Chanmin Su Veeco Instruments Inc., Santa Barbara, CA *Marena Systems, 3563 Investment Blvd., Hayward, CA 94545

2 The Problem: NanoAsperity Induced Failures NanoAsperity (na) refers to nano particles with height of 1-10 nm and diameter <100nm on media substrates. v Head These surface defects are typically burnished (removed) with the Disk Drive Head. Too many na s cause excessive wear on the disk drive head affecting the DLC protective coating. Results in either immediate failure or worse a reliability failure. Disc clr

3 Nano-Asperity Generation These nano-defects are believed to be caused primarily by the batch cleaning process. LMR PMR Mechanical Texture Media Wash Sputtering Backend Processing Test Media Wash Sputtering Backend Processing Test Need a tool to assist in identifying substrate lots where process has changed and caused unacceptably high number of nano-asperities.

4 AFM: the Best Tool to Measure NanoAsperity AFM can easily detect na and quantify both the height and size of it. 50nm 1.7nm 1µm

5 Current AFM Monitors Have Limitations Low throughput increases Cost of Ownership Require skilled and trained technicians Manual operations & full time attendance Developing Dimension NanoAsperity Fast survey scans and advanced algorithm for na detection (Patent pending technologies) High speed, automatic scans for na quantification Simple operations and easy user interface Multiple tools per operator

6 FeedForward Technology for XY Scan High bandwidth closed loop XY performance Reduce scanner ringing at turn around Enable fast scanning Up to 7X faster!

7 Fast Survey Scan: Size Trace Retrace 20µm x 10µm 2048 pixel X1024 lines Total of 9 na detected within this area

8 Automatic Detail Scan: Size

9 Advanced Pattern Recognition Algorithm No. 5 No. 6 Survey scan detected 6 na in this area. Detail scans from large to small Adjustable lower limit on na height

10 Detection Correlation Studies: Fast vs. Slow Scan rate 0.5Hz Scan rate 7.3Hz Fast survey scan provides only for na detection. Higher sensitivity for na detection in fast survey scan. No quantitative measurement from survey scan. Demonstrated good correlation between fast and slow scans.

11 Easy to Use Operator Interface Engineering Setup can be transferred to production sites Transportable recipes eliminate requirement of skilled operators Saves images in uniquely named files Reports current operational status

12 Key Software Features for Engineer Setup is password protected and is portable to different AFM systems. Site panel defines a specific set of imaging sites. AFM panel defines the AFM control parameters including Auto Feedback Gain adjustment. Algorithms and results panel defines the na height detection sensitivity. TCP/IP panel allows data transfer for offline analysis.

13 System Stability and Tip Life The system has continuously scanned 352 site images and 2332 na images for 40 hours. Total of 7 na detected from this area

14 Detail na Scan: Size This probe has continuously scanned 352 site images and 2332 na images for 40 hours. Image RMS=0.15 nm Image RMS=0.13 nm 62nm 2.5nm 1µm

15 Dimension NanoAsperity: An Automated Tool Dimension NanoAsperity is a complete system Dimension V AFM Hybrid scanner Disk sample chuck Environmental control Automation and Control System Software License Engineering setup -- Protected operator execution

16 Dimension NanoAsperity System Specs Throughput: < 31 minutes for 8 regions of 20um x 10um plus 1 additional minute per Nano-Asperity. NA Minimum Lateral Detection: 15nm on 2048 x 1024 scan resolution Detected Throughput: NA Lateral Resolution<31 minutes 2nm on 512 x512 for detail scan 8 (pixel regions resolution) NA Height Detection: 1.2 nm to 10nm ** NA plus Height Repeatability: 1 additional minute 20%, 1 Sigmaper na Height Noise < 0.6 Angstroms when installed in a BBN Criterion C environment. Note: environments above the BBN Criterion C may require an optional Active Vibration Table to reduce noise. Acoustic Noise Environment must be <75 db to achieve performance Scan Area Size: Predefined Area Scans: Scan Speeds: Scan Resolution: Average Tip Lifetime ** Throughput Comparison Dimension V ~45minutes for 300 um2 **Provisional specs final specs to be completed by Q3/08 up to 20um x 10um regions (max) 1 to 8 User Selected Regions ~ 7 Hz for the survey scan; ~11 Hz for the detail scan Survey Scan: 2048 pixels per X line; 1024 lines Y direction Detail Scan: 512 pixels per X line; 512 lines Y direction ~ 120 scans (20u x 10u); Actual lifetime depends upon environment including substrate contamination levels. na Height Detection: 1.2nm to 10nm Dimension ηasperity ~32 minutes + 1 minute for each detail scan for 1600 um2 na Height Repeatability: 20% 1 Sigma 225µm 2 /hour 900µm 2 /hour with average of 3 NAs (>400% improvement in throughput) ** Specifications subject to change

17 Concluding Remarks Fast scan enabled by FeedForward technology Automatic detail scans from advanced detection algorithm for accurate measurement Engineer controlled transportable recipes Automated tool for high throughput production use!

18 Backup Slides

19 Detail na Scan: Size With a new tapping probe Image RMS=0.15 nm 48nm 2.0 nm 1µm

20 Comparative Throughput Increased Scanning speed Survey 7Hz Detail 11 Hz Overhead of Engagement 3 Minutes NA Detail Scan Conducted when Survey shows anomaly. Increases NA image resolution to 2nm Dimension ηa Dimension V Scan Rate Scan Size - X Scan Size - Y # Scan Regions 8 8 Lines Per Y Scan Data per X Scan Time Per Region Scan XY Translation (min) 0.42 Regional Engagement(min) 0.75 Regional Optimization(min) 0.35 Total Min / Substrate NA Defect Detail Number of NA 3 Not Performed Scan Size - X 1 Scan Size - Y 1 Scan Rate 11 Lines per Y Scan 512 Data per X Scan 512 Time per NA (min) 0.78 All images are available for offline user analysis or reporting. Total NA Time 2.33 Total Test Time

21 Dimension NanoAsperity Advantages Detection and Quantification of nano-defects on the surface of ultra smooth (<3A) Aluminum media substrates. Ability to monitor lots with high defects to stop problems which lead to expensive disk failures. Enables operators to run production monitors freeing technicians and engineers to focus on production improvements. Dimension NanoAsperity enables increased sampling sizes with the advanced accuracy to measure nano-asperities (na) with a lower cost of test.

22 Dimension NanoAsperity Benefits Complete Package Increased Throughput of up to 4x Scanner Parameters Optimization Ergonomic Hood Multi-site Automation Recipe Transportability Engineering/Operator Modes Password Access Single Operator Multiple Tools Lower Cost of Production Control Survey Scan 7 Hz; 1024 bit density Up to 20um x 10um Detail Scan 11 Hz; 512 bits 1 um x 1 um 2nm pixel resolution

23 Acknowledgement Dr. Xinwei Li Seagate Recording Media, Fremont Dr. Raj Thangaraj Tribology Fundamentals Group Seagate RMO, Fremont Michael Peters and Hector Lara Veeco Instruments