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Flip
Chip CSP
Flip Chip BGA
HP Flip Chip BGA
Bumping
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Product
Overview
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| Flip chip derives its name from the method of flipping over the chip to connect with the substrate or leadframe. Unlike conventional wire bonding interconnection methods, flip chip uses solder bumps meaning that the I/O pads are not only distributed on the peripheral of the chip, but over the entire surface. As a result, the chip size can be shrunk, the circuit path can be optimized, and in the absence of bonding wire, signal inductance dramatically reduced. Critical to the flip chip packaging process is wafer bumping, which is an advanced packaging technique where bumps or balls made of solder are formed on the wafer before it is diced into individual chips. This bumping technology is essential for applications requiring higher performance, reduced form-factor and greater density, which are too complex for traditional interconnection methods. ASE has invested significantly in the research and development, as well as in equipment for wafer bumping. It has the capacity to bump 6-inch, 8-inch, and 12-inch wafers. |
| Flip
chip technology is gaining popularity due to: |
- Shorter assembly cycle time – All the bonding for flip chip packages is completed in one process.
- Higher signal
density & smaller
die size - Area array pad layout increases I/O
density. Also, based on the same number of I/Os,
the size of the die can be significantly shrunk.
- Good electrical
performance - Shorter path between die and substrate
improves the electrical performance.
- Direct thermal dissipation
path - External heat sink can be directly added
to the chip to remove the heat.
- Lower packaging
profile - Absence of wire and molding allows
flip chip packages to feature lower profiles.
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| Filp
Chip in ASE |
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- FC-CSP (Flip Chip Chip Scale Package) offers chip scale capability for I/Os around 200 or less, and provides better IC protection and better solder joint reliabilitycompared with direct chip attach (DCA) or chip on board (COB). FC-CSP is superior to known good die (KGD) in low-cost test and burn-in, and performs comparable electrical function with KGD. FC-CSP features thin and small profile, and lightweight packages. Applications include RFICs and memory ICs. ASE provides this packaging service for any customer-designed size at ball pitches ranging from 0.5 to 1.0mm, and no. of I/Os from 16 to 200. The types of encapsulation are underfill and overmold.
- Ceramic FC-BGA/PGA – Ceramic substrate offers better moisture resistance. Improred electrical insulating properties and higher thermal conductivity than organic substrate. High Pb solder ball with eutectic solder paste improves board level reliability performance of ceramic packages.
- FC-BGA & High performance FC-BGA (HFC-BGA) – These two packages cater to I/Os of 100 to over 1500 with BT laminate or sophisticated multi-layer build-up substrates. HFC-BGA is thermally enhanced through mounting a metal heat sink to the rear side of the chip and the substrate. This method can effectively remove heat and improve the thermal performance.
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| Complete
Flip Chip Solutions |
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| ASE provides complete flip chip services from packaging characterization, substrate design, wafer bumping, wafer sort, flip chip assembly to final test. This total turn-key solution ensures a broad portfolio of high performance and high quality flip chip packages to meet customers’ requirements. |
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| Flip
Chip Packages |
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| The thickness and ball count of flip chip packages are mostly customized. However, ASE provides several options for enhancing the performance of flip chip packages. These are: |
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- Over molding (for FC-CSP) – The molding is used to protect the chip, substituting underfill to lower cost and improve the thermal performance and 2nd levelreliability.
- Heat spreader (for FC-BGA) – The heat spreader provides direct heat conduction by adhering to the rear side of the silicon chip. This method provides 6~8W of thermal dissipation under natural convection.
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| (For more FC-CSP and FC-BGA information about process, outline dimension and packing, please refer to Flip Chip BGAs.) |
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