LMR And PMR Media Update - IDEMAPMR Introduction • At the media level, many problems remain to be...
Transcript of LMR And PMR Media Update - IDEMAPMR Introduction • At the media level, many problems remain to be...
March 2005
Komag Inc.1710 Automation Parkway
San Jose, CA 95131
Presented byMichael A. Russak, Ph.D.
President & Chief Technical Officer
LMR And PMR Media Update
March 2005
The material presented here was generated and kindly provided to the presenter by Dr. Gerardo Bertero and
his team at Komag.
March 2005
Outline of Presentation
• LMR Media for 160 GB/Platter Products• State-of-the-Art Media• Where to expect SNR to come from• Low MrT, thermally stable TMR media
• Komag’s Perpendicular Media• Current Status:
• CoCrPtBO-media• Storage Layer• Interlayer• SUL
• Summary
March 2005
Issues and Challenges for LMR Media
• While a lot of effort is being focused on PMR media development, the bulk of our efforts is still in LMR media.
• SNR improvement is more likely to come from narrowing the transition parameter than by grain size reduction.
• From a media perspective, Hc, MrT and overcoat thickness are extrinsically bounded.
• Grain size uniformity and OR are key features to improve the transition parameter in media.
• Introduction of TMR heads allowing MrT reduction, while challenging, opens up opportunity for further improvements in SNR.
March 2005
SNR Vs. Grain Size and Transition Parameter
30
28
26
24
22
20
18
16
SNR
1514131211109876543 Grain Size, Transition Parameter (nm)
10.9 dB
2.5 dB
W-C Transition Parameter Grain Size
~ 3 dB
35 Gb/in2
100 Gb/in2
67 Gb/in2
125 Gb/in2
At 125 Gb/in2 products there is opportunity to reduce transition parameter with lower MrT media with use of low noise TMR heads.
⎥⎦⎤
⎢⎣⎡=
SaBWPWLogSNR 2
5031.010
March 2005
SAF LMR Media Structure
Strong focus on nucleation layer and exchange layers for grain size uniformity and thermal stability
Stabilizing Layer:Ru
M
Top Magnetic Layers: M
Underlayers
March 2005
HRTEM Image of LMR Mag. Layer
<G.S.> = 6.0 nm; <C.C.D.> = ~ 8.0 nm
5 nmSP3
4.2 Å
6.3 nm
6.6 nm
9.0 nm9.1 nm
8.1 nm
9.0 nm
9.0 nm
6.7 nm
7.8 nm
8.0 nm
6.6 nm
6.7 nm
7.8 nm
8.7 nm
8.0 nm
8.2 nm
6.8
nm
7.6 nm7.7 nm
7.5 nm 8.3 nm
9.1 nm
8.7
nm7.2 nm
11.0 nm 10.0 nm
8.1nm
8.1 nm8.5 nm
8.5 nm
March 2005
State-of-the-Art Media Microstructure
100 nm
March 2005
SNR Improvement Through OR
200 nm200 nm
Line scan for texture line density Line scan for texture line density
Sample 1 Sample 2
March 2005
SNR Improvement Through ORIn
tens
ity (a
.u.)
Inte
nsity
(a.u
.)Distance (nm) Distance (nm)
0 01000 1000
Sample 1: Sample 2:
60 texture line/1 µm 65 texture line/1 µm
MrT OR: 1.7 MrT OR: 1.8
March 2005
LMR Media Improvement Path
• Grain Size reduction cannot be too aggressive from now on.• Grain size uniformity will improve as we refine process in
complex SAF media stack.• Through UL and,• Nucleation layer processing.
• Most media SNR gains will be realized through slimming of the transition parameter.
• Lower MrT (~ 0.3 memu/cm2) will be possible by introduction of low noise TMR heads.
• Thermal stability will be kept by:• Increasing MrT cancellation of SAF media.• Improving dHc/dT of the media alloy.• Improving grain size uniformity.
March 2005
Final Thoughts on LMR
• 80 GB/Platter (~65 Gb/in2) is mature technology but is still good for >1 year
• 100 and 120 GB/Platter technology is starting to ship (shortly) and will live for (1-2 ?) Years
• 160 GB/Platter drives are not just ready yet but they are on LMR platforms.
Granted that PMR may be introduced in 2005 in small programs(and small form factors) but ….
• LMR has at least 3 more years of life and will probably co-exist with PMR for a few more years before PMR takes over completely.
Perpendicular Media
March 2005
PMR Introduction
• Technology hurdles in PMR technology are no longer show stoppers.
• However, PMR technology still faces major problems, e.g.,• Media/Head manufacturability (mainly media)• Wide area track erasure• Channel technology• Servo writing• Magnetic state of the finished media (e.g., DC or AC magnetized ?)• SUL magnetic directionality setting• Mechanical reliability
• Given the plethora of problems and unknowns, the first PMR programs will be very small.
March 2005
PMR Introduction
• At the media level, many problems remain to be solved before we can be ready for manufacturing,
• SNR improvement.• Better uniformity and throughput/utilization.• Domain-free magnetic soft underlayers. • Bulk erase process for AC remanent state.• Robust tribology.
March 2005
CoCrPt-Oxide Perpendicular Media Structure
Inter-layers
Substrate (AlMg or Glass)Substrate (AlMg or Glass)
OvercoatCoCrPtO Hard Magnetic Layer (~15 nm)
Seed LayerRu (10 Ru (10 –– 20 nm)20 nm)
Soft Magnetic Layer (60 – 120 nm)
March 2005
Typical Layer Thickness in PMR Media
15.5 nm14.3 nm2.1 nm
0.9 nm
95 nm 45 nm
95 nm 45 nm
191 nm 91 nm
March 2005
Plan-view Bright Field TEM Image & SADP
March 2005
Nucleation Layer
• We’ve developed a new family of nucleation layer structures that allow us to reach much higher Hc.
• These new NLs also provide smaller magnetic grain sizes and more magnetic grain isolation.
• Media SNR gain is ~ 1 dB.
• Overall NL thickness is still large (minimum at ~14 nm).
• Need to develop a <10 nm process.
March 2005
Nucleation Layer Grain Size Analysis
NL Thickness is the same among these samples
March 2005
Perpendicular Media: SNR Evolution22
20
18
16
14
12
10
8
6
4
2
SNR
[dB
]
50454035302520151050
Time [months]
- 6 dB
+ 11.6 dB
- Boron Alloy Media - Oxide Alloy Media
Dec. 2000 March 2005
March 2005
Summary
• LMR will be extendable to at least 150 Gbit/in2- TMR HEADS- Adjustable Fly Height
• SAF structures will be the end for LMR
• PMR will penetrate in SFF, low volume HDD programs- Toshiba 48mm – mid-2005
• PMR still in need of process and performance improvement