advanced IC_Packaging_technology_overview

• ALL Use mechanical based tools for design (AutoCAD)
– NOT a Good Fit For APD – 75% of IC’s are in Lead Frame Packages
IC Package Types Continued…
• BGA- Ball Grid Array
• Build-up is Less Expensive Than LTCC. However, LTCC Exhibits Better Die Shrink Support with Same Build-Up Arrangement (a 3/2/3 process)
• Die Cost (size) Drives Use of Flip-Chip, Build-Up Process
• Used in Lead Frame, PGA and BGA packaging
• Over 80% of Packages are Wirebonded
• Epoxy Glue to Attach Chip • Typically Gold Wire
– Also Copper, Aluminum
Advantages of Flip-Chip
• Reduced Signal Inductance
– Shorter Interconnect Lengths
• Use Power More Efficiently
– Power Directly at the Core
• Higher Interconnect Density
– Under-fill epoxy is used to secure the attachment and absorb stress
– The chip is then “flipped” face down onto the package carrier using a reflow process – Bump sizes range from 90-125 microns in diameter – Also known as C4 (Controlled Collapsible Chip Connection)
– Flex Tape and Wirebond also possible
• Common for Wireless Handsets and Handheld Electronics . • Stacked die support (S-CSP- Stacked CSP) • Laminate and Ceramic Substrates
IC Package Types (Lead Frame)
• PQFP- Plastic Quad Flat Pack
– Up to 304 pins (500 micron pitch) – Inexpensive (~ a penny per pin) – Hermetic (Good for Harsh Environments) – Smaller ASICs and lower performance, lower pin count Microprocessors.
• Based on High Density, Micro Via Organic Substrate
– Also Referred To As Sequential Build-up
– Requires Flip-Chip Escape Route Patterns
– Typical Package Assembly Based on a 2layer Core and Build-Up From Each Side of Core – i.e. 3/2/3 process equals 3 build-up layers from each core side
• High Pin Count ASICs and Microprocessors • Typical Package is CBGA or TBGA (> 600 pins) • Tape Carrier Package Used for < 600 pins
Flip-Chip…The Build-Up Process
2layer core
Flip-Chip…The Build-Up Process
• Layer to Layer Connections Typically Use:
– Micro-Vias of 100um or Less
– Special Patterns (Stagger, Staircase, etc.) – Core Vias Larger Than Micro Vias – Lines and Spaces < 35um
– PBGA (Plastic BGA)
– Routable Laminate Substrate (Many Layers) – High Pin Count (Over 2000 pins)
– ASICs, DSPs, PC Chipsets
– Wirebond, TAB or Flip-Chip (Build-Up) attach – Build-Up Technology Requires Special Via Structures – Can support Via in Balls (uncommon)
– Usually Flip-Chip and SiP (MCM) – Supports Smaller Feature Sizes (Interconnect Density) – Supports Via in Ball – Support for Die Cavities – More Expensive, Reliability Questions
• Supports Smaller On-chip Pin Size and Pitch • Supports up to 850 Pins
• Better Electrical Performance than Wirebonds
• Area TAB for Flip-Chip
Flip-Chip (C4) Attachment
• TSOP- Thin Small Outline Package (TQFP- Thin QFP)
– Very Low Profile
– Common for Memory – Can Support Stacked Die – Can Support Flip chip
• PLCC, SOIC, MLF, DIP, SIP, etc– Smaller Pin Count (4-84 pins)
• Two methods of “Bumping” the Chip:
– RDL- Re-Distribution Layer
– Direct Bumping (UBM)
More Flip-Chip…
• Stud Bumping
– Direct Gold Bump Placed on Die Bond Pad – Supports Tighter Pin Pitch
• Use of Mesh Planes for Fabrication Yields
– IBM
Unique uvia Patterns Core via vs. uvia
CSP- Chip Scale Packaging
• Definition: A Package is Considered CSP when it is Less than 20% Larger than the Die. • Usually Flip-Chip Attachment
– Invented by IBM
Flip-Chip Continued
• Flip-Chip is NOT:
– A Specific Substrate Material like LTCC or FR4
– A Specific Package like SOIC
– A Specific Package Type like QFP, BGA or PGA
Advanced IC Packaging A Technology Overvik C. Moll
A Chip is Useless w/out a Package
• Delivers power to the Chip • Transfers information into and out of the Chip to the PCB • Draws heat away from the Chip • Protects the Chip from outside elements
– More Routable Area
• Smaller Package Size
– Chip Scale Packaging (CSP)
• I/O Not Controlling Core Size
– Area Array Placement – Possible Die Shrink
More about Flip-Chip
– Wire length- typ. 1-5 mm – Wire diam.- typ 25-35 µm
– Inexpensive, Reliable
TAB (Tape Automated Bonding)
• Interconnect Patterned On Tape
• Stronger Lead Bonding Strength
BGA Continued…
• BGA- Ball Grid Array
– TBGA (Tape BGA)