Advanced Packaging

Flip Chip, Wafer level and 3D memories

CSP, BGA, PoP, Fan in, Fan out

Chip on Board COB Flip Chip CSP Flip Chip BGA Package On Package (PoP) Memory

Flip Chip CSP

Flip chip means flipping over the chip to connect with the substrate or leadframe. Flip chip uses solder or bumps like copper pillar for interconnection other than conventional wire bonding. The I/O pads can be distributed all over the surface of the chip, thus the chip size can be shrunk with an optimized circuit path. The absence of a bonding wire also help reduce signal inductance. The key features of Flip Chip packages:

Enhanced electrical performance. It provides a shorter path between die and substrate and eliminates the z-height impact of wire bond loops.
Increased routing/signal density with small size. Coupled with copper pillar bumped die, flip chip technology could reduce layer count and cost applying fine line/space substrate routing and bump pitch.
High Manufacture Efficiency. The package is processed in a strip format and all the bonding is completed in one process wafer bumping.
Direct Heat dissipation path. An integrated heat spreader and external heat sink can be directly applied to remove heat.

FCCSP (Flip Chip Chip Scale Package) offers chip scale capacity for I/Os around 200 or less. FCCSP provides better protection for chip and better solder joint reliability compared with direct chip attach (DCA) or chip on board (COB). FCCSP features thin and small profile, and lightweight packages.

KEY FEATURES

Suitable for low and high-frequency applications
Electroplated Pb-free or Cu pillar bumps
Coreless, thin core, laminate, and molded substrate construction
Bare die, over-molded, exposed die molded constructions
Molded underfill (MUF) or Capillary underfill (CUF) options
BGA ball pitches down to 0.1 mm scale
Bump pitches with Cu pillar down to 0.01mm scale
Package thicknesses down to 0.35 mm
Accommodates package sizes from 1×1 mm2 to 25×25 mm2
Heat spreader attach available for high-power devices
Bottom-side chip attach available for Antenna in Package (AiP) applications

APPLICATIONS

Mobile processor (smart phones, tablet, wearable electronics); consumer and automotive.
Chipsets for peripheral IC, RF, PMIC, Sensors/MEMS, connectivity

RELIABILITY

Moisture Sensitivity Level: JEDEC Level 3@260°C
Temperature Cycling Test: -55°C/125°C, 1000 cycles
High Temperature Storage: 150°C, 1000hrs
Highly Accelerated Stress Test: 130°C, 85%RH, 2 atm, 96 hrs

The above are typical condition numbers.

Overmold For FCCSP

There are two ways of overmolding for FCCSP. One is using capillary underfills (CUF), the other one is using epoxy molding compound to substitute underfill (MUF) for lower cost, improve the thermal performance and 2nd level reliability.

Product Recommendation For FCCSP Overmolding
Semicondutor Capillary Underfill (CUF)	Board Level Underfill	Epoxy Molding Compound Mold Underfill (MUF)
LOCTITE ECCOBOND NCP5209 LOCTITE ABLESTIK NCF218 LOCTITE ECCOBOND UF8830S	LOCTITE ECCOBOND FP4526 UF8828 FP4511 FP4549 (HT)	Hysol GR920 Series
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	Excellent narrow space filling with ultra-fine filler cut (20um) Meet MSL2~3 @260°C requirements Outstanding warpage control (unit warpage<80um) Meet UL94 V-0 flammability at 1/8 inch thickness Good reliability performance on advanced packaging

Mold Underfill Epoxy Molding Compound GR920

Property / Product	Unit of Measure	Hysol GR920 H4	Hysol GR920 Q2	Hysol GR910 M12	Hysol GR910 L20	Hysol GR920 A1
UNCURED PROPERTIES
Epoxy Type		MAR	MAR/MF	MAR/BP	MAR/MF	BP
Hardener Type		MAR	MAR/MF	MAR	MAR/MF	PN/MF
Filler cut	µm	20	20	20	20	20
Filler content	%	84	85	88.5	88	87.5
Filler Type		Spherical	Spherical	Spherical	Spherical	Spherical
Hot Plate Gel time, @ 175°C	s	34	39	37	34	46
Spiral Flow @ 175°C	inch	60	56	39	36	66
Halogen-free (Green)		✔	✔	✔	✔	✔
TYPICAL CURED PROPERTIES
Glass Transition Temperature, TMA	°C	102	138	120	158	150
Coefficient of Thermal Expansion (CTE)
Alpha1, TMA	ppm/°C	14	12	10	9	9
Alpha2, TMA	ppm/°C	43	45	35	33	34
Glass Transition Temperature, DMA	°C	113	146	127	156	151
Flexural Strength @25°C	MPa	125	146	120	154	138
Flexural Modulus @25°C	MPa	13500	15500	19500	17800	24000
Modulus by DMA @25°C	Mpa	21000	20700	24000	25914	24000
Modulus by DMA @175°C	Mpa	350	1200	950	2119	2000
Modulus by DMA @260°C	Mpa	235	650	650	1203	1100
Water Absorption, 24hr PCT	%	-	-	-	0.37	0.38
Mold Shrinkage PMC	%	0.36	0.26	0.13	0.20	0.19
Shore D Hardness	-	76	77	76	81	80

Board-Level Underfills for CSP

They are used for mechanical reinforcement and to improve the thermal cycling performance. These underfills are used to absorb the CTE mismatch between the die and the substrate the die is placed on. They increase the reliability by distributing stress across the surface of the die or the substrate instead of being concentrated in the solder balls, especially during thermal cycling.

There are three main underfill types:

1. Capillary Underfill