failure analysis

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failure analysis
enabling

• an overview of

FA Sample Preparation
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Selected Area Preparation
Silicon Thinning on ASAP-1
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(No Transcript)
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KEY PRODUCT AREAS
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• Precision Sawing
• Precision Lapping and Polishing
• Deprocessing
• Cross-section Preparation
• Consumable Products
• Selected Area Preparation
• Backside Analysis
• Mechanical Decapsulation

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ULTRA TEC Precision Sawing
ULTRASLICE 6000 Precision Saw
ULTRATRIM Diamond Trim Saw
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Production ofPHYSICAL CROSS-SECTIONS
SEMI-AUTOMATIC X-sectioning a CPGA package with
ULTRASLICE 6000
MANUAL X-sectioning a BGA package with ULTRATRIM
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Analyzing Physical Cross-sections
ULTRA TECs Measuring Microscope allows for the
determination of package layer thicknesses --
allowing for selected area and other preparation
protocols to be created.
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Lapping Polishing
MULTIPOL TRUE FLAT LAPPING MACHINE
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Ensuring Parallel Polishing
NEW TECHNOLOGY!
1 micronAccuracy Precision Micromount
Sub-micron Accuracy ULTRACOLLIMATOR
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Selected AreaPreparationfor. Backside
Analysis Decapsulation
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ASAP-1Selected Area Preparation System
MARKET LEADING SOLUTION
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How thin do we need to thin ?

• 100 microns remaining silicon usually thin enough
  for heavily-doped substrates
• 50 to 80 microns ensures effective imaging
• On lightly-doped substrates, 250 microns can be
  okay

Machinery discussed here can routinely Thin to lt
25 microns thickness
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Using the Silicon Filter

• Light Transmission

Microns of remaining silicon
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Objective of Backside Selected Area Preparation

• Remove package materials -- when die is
  encapsulated
• Mechanically Thin substrate (die) to a known
  remaining thickness
• Polish the surface to allow backside analysis

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Schematic of backside preparation
1. PACKAGE to be prepared
2. A series of ASAP-1 tools is used to remove
package and substrate material and polish
3. The circuit is biased and package analyzed on
a backside microscope with I-R illumination
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TEMP. RISE DURING PROCESS
Note Dry Grinding is not recommended. Dry grind
figures are to illustrate the difference in
thermal energy introduced by both Milling
(deterministic) and ASAP-1 (reactive) approaches
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DETERMINISITIC vs REACTIVE
High Damage
Low Damage
Incremental Positive Steps
Gradual Wearing Away
Preset positive stop
Target
Target
REACTIVE ACTION e.g. ASAP-1
DETERMINISTIC ACTION e.g. Chip Unzip
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Backside Prep - Process Steps
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Which Size of Tool to use ?
The above sizes are standard. Other sizes are
available on request.
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Easy Amplitude Set (Die or Cavity Size)
Read-out
Set Amplitude ½ Die Size ½ Tool Ø
Allowance
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Testing Image Quality
Remaining Silicon Thickness ? F n t ? F is
the difference in focus from polished surface to
circuit n is the r.i. Of Silicon (approx 3.66) t
is the silicon thickness
INFRATEC-1 Backside Microscope
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NIR Imaging Quality
Image taken with 2x objective on Alpha Innotech
FALCON PEM Note The background to this
presentation is the same part viewed with 100x
objective
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Adjusting for Die tilt
Die
X
Y
Copper Remnant
Simple tilt accommodation is made after the
tell-tale non-cleanup of copper paddle /
silver halide epoxy
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Sample Applications
FLIP CHIP
CERAMICS
CPGA thinning and polishing topside has been
glob topped to allow for backside prep
large flip-chip device Die size 31mm square
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Sample Applications
Very Small Devices Sub-mm tools can be used to
thin very small areas on MEMS And surface-mount
devices
POWER CHIP PQFP with extremely thick die
paddle, (approx 3mm thick) after polishing
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Sample Applications - 8 Wafer
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Sample Applications Extremely Thin Substrates
50x Magnification
1000x Magnification
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Sample Applications - Decapsulation
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Anti-reflective Coating (ARC) for
BACKSIDE ANALYSIS
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ARC - lite
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Features of ARC- lite

• Improves contrast up to 60
• Improves emission sensitivity up to 30
• Coating times are fast ( 45 secs)
• Coating done at room temperature
• System is bench-top can be positioned alongside
  ASAP-1 and/or microscope
• Low cost

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Application of Imaging Fluid
First apply ARC-lite solvent to prepare surface
run cycle Then apply 2-3 drops of imaging fluid,
and start cycle If re-coat is required run
cleaning cycle first, then re-coat
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Sample After AR Coating
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Before and After ARC Example 1
20x objective before ARC
20x objective after ARC
Imaged with IC Diagnostics Videre System
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Before and After ARC Example 2
5x objective before ARC
5x objective after ARC
Imaged with Hypervision V2 emission microscope
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