Ball grid arrays are one of the most prominent technologies at the moment and are the main connectivity type for flip chips. Flip chip assemblies are much smaller than traditional carrier-based systems. The chip sits directly on the circuit board, and is much smaller than the carrier both in area and height. Having no wires greatly reduces inductance, a property that allows higher-speed signals and better heat conductivity. Flip chips are not suitable for easy replacement, or manual installation. They also require very flat mounting surfaces, which is not always easy to arrange, and they are sometimes difficult to maintain as the boards heat and cool. Also, the short connections are very stiff, so the thermal expansion of the chip must be matched to the supporting board or the connections can crack.

 

Flip Chip BGA (FCBGA) packages are assembled around state‑of‑the‑art, single unit laminate or ceramic substrates: (1) Flip Chip Organic BGA - Laminate or build-up organic substrate offers better electrical performance than wire-bond type BGA package especially in high frequency applications; (2) Flip Chip Ceramic BGA - Alumina ceramic substrate offers better moisture resistance, electrical insulating property and higher thermal conductivity than organic substrate. FCBGA is used primarily for high-reliability commercial applications (e.g. CPU). By combining flip chip interconnect with ultra advanced substrate technology, FCBGA packages can be electrically tuned for maximum electrical performance with a high routing density. 

Product Recommendation For FCBGA Assembly
Semicondutor Capillary Underfill (CUF)	Board Level Underfill	Lid Attach Adhesive For BGA
Locitite ECCOBOND NCP5209 Locitite ABLESTIK NCF218  Locitite ECCOBOND UF8830S	Loctite ECCOBOND FP4526 UF8828 FP4511 FP4549 (HT)	Conductive Lid Attach CE3920 ICP3920 3185 QMI529HT Non conductive Lid Attach MC723 3003 3005 3188
Bump protection of flip-chip devices, with bump pitches less than 100 µm and gaps less than 40 µm Enables fine pitch, narrow gap Cu pillar TSV, Die to die & Die to substrate Achieves MSL L3/L2A and passes all reliability requirements Excellent wettability to different substrates	Mechanical reinforcement and improve the thermal cycling performance. Absorb the CTE mismatch between the die and the substrate the die is placed on. Distribute stress across the surface of the die or the substrate instead of being concentrated in the solder balls, especially during thermal cycling. For capillary flow on flip chip applications with excellent reliability

Conductive Lid Attach

• CE3920
• ICP3920
• 3185
• QMI529HT

 

Non conductive Lid Attach

• MC723
• 3003
• 3005
• 3188

Integrated circuits are extremely vulnerable packages that need protection from the outside world. They need to be thermally, mechanically and electrically insulated in order to endure operational conditions.

 

Nearby components can be too warm or too dense for the die that needs to be covered and protected from dust, heat, moisture and ensure the environmental protection and mechanical strength needed.

 

Encapsulants for BGA packages:

• FP4451TD
• FP4450HF
• FP4651
• FP4802
• FP4460
• UV9060F
• EO7021

Ball grid arrays rely on microscopic and extremely precise connections to keep things running. Soldes spheres have their own mechanical and thermal properties, but normal operating conditions for most devices are too rough to handle for most components and are even worse for those hundreds of tiny (down to 0.100mm) solder balls. Even one failed connection can mess with the entire circuit and make the device unusable. To solve these issues while maintaining all of the BGA advantages, we came up with the underfills. Underfills go between the solder balls and create a solid surface with great properties that help our devices withstand the daily struggle. 

Additionally, underfills help with thermal expansion that can also cause serious issue and cracks.  The underfill material acts as an intermediate between the difference in CTE of the chip and board providing the leeway and flexibility required under thermal stress.