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 2.5D Packaging Fan-Out Packaging (FO-WLP & FO-PLP)

Flip Chip BGA

Advanced Packaging Solutions

Flip Chip BGA Materials and Interface Solutions

Flip Chip Ball Grid Array, or FCBGA, is a substrate-based package architecture used for high-I/O, high-performance semiconductor devices where interconnect density, thermal path design, package warpage, and long-term reliability must be managed together. CAPLINQ and Krayden support FCBGA programs with underfills, molded-package materials, lid attach adhesives, encapsulants, and thermal interface materials mapped to the interfaces that govern package performance.

This page explains how FCBGA packages are built, where materials matter, and how Hysol, Henkel, LINQ, and other supplier portfolios available through Krayden align to the application.

At a glance

Application: FCBGA substrate packages
Primary drivers: fine-pitch interconnect support, warpage control, thermal path management, hidden-defect reliability
Main package uses: CPU, GPU, APU, memory, networking, high-density computing
Typical references: MSL screening, TCT, HTS, HAST, board-level fatigue evaluation

Jump to sections: Application Overview Key Interfaces Featured Solutions

FCBGA Application Overview

Flip chip assemblies are smaller and electrically shorter than traditional carrier-based wire-bond systems because the die is connected directly to the substrate through an area-array interconnect. The shorter connection path reduces inductance and supports higher-speed signaling, but it also makes the package more sensitive to stiffness mismatch, warpage, surface planarity, and hidden interconnect defects.

FCBGA packages are assembled on laminate or ceramic substrates. Organic substrate designs are widely used where routing density and electrical performance are required at scalable cost, while ceramic designs remain relevant where insulation stability, moisture resistance, or higher thermal conductivity matter more. In both cases, the material stack must be matched to the package architecture rather than selected as disconnected products.

The most important engineering question is not simply which adhesive, underfill, or EMC to use. It is which interface dominates package risk, die-to-substrate interconnect, underfill route, molded package strategy, lid stack, or board-level fatigue path.

Fine-pitch interconnects

Low warpage package design

Lid and thermal path control

Hidden-defect reliability

Substrate package protection

FCBGA Package Architecture and Process Landscape

A typical FCBGA package contains a silicon die, solder bumps or Cu pillars, under-bump metallurgy, an underfill or molded reinforcement layer, a substrate with build-up routing, BGA solder balls for board attach, and in many cases a lid or heat spreader with thermal interface materials. Material selection is shaped by pitch, stand-off, die size, substrate type, thermal demand, and the failure mode that dominates the end use.

Conventional reflow plus capillary underfill remains relevant for many mainstream packages. Thermal compression bonding with NCP or NCF becomes more attractive as pitch tightens, while molded-underfill or full molded-FCBGA strategies become relevant when package protection, warpage control, or severe-use reliability justify a molding-based route.

Conventional Architecture for FCBGA Packages

Direct die-to-substrate interconnect with reinforced stress path

In a standard FCBGA configuration, the die is connected directly to the substrate by solder bumps or Cu pillars, then reinforced by underfill or molded protection before the completed package is attached to the PCB through solder balls. If the package uses a lid, the thermal path and package curvature response are further shaped by lid attach and thermal interface materials.

The material stack must therefore do more than fill or bond. It must support stress redistribution, heat flow, hidden-interface reliability, and manufacturability across multiple process steps.

Die

→

First-Level Interconnect

→

Underfill or Molded Reinforcement

→

Substrate and BGA Attach

Baseline flow: source generation, local interconnect, reinforcement, substrate routing, board-level connection

Key Engineering Challenges in FCBGA Packages

Warpage and coplanarity control

As package size, stiffness gradients, and thermal load increase, the limiting factor often shifts from simple assembly success to curvature control through cure, reflow, and cycling.

Fine-pitch reinforcement

As stand-off decreases and pitch tightens, underfill route selection becomes more sensitive to gap access, viscosity, wetting, and void control.

Thermal path versus mechanical stress

Lid attach, TIM, and molded-package choices are used to support heat transfer, but they also alter bondline stress, package stiffness, and second-level fatigue behavior.

Key Interfaces and Material Integration

Materials in FCBGA are selected at interfaces, not in isolation. Some steps need interconnect reinforcement, some need package protection, some need heat transfer, and some require controlled compliance to prevent fatigue from shifting downstream.

Die-to-Substrate Attach

→

Interconnect Reinforcement

→

Lid and Thermal Path

→

Board-Level Reliability

Die-to-substrate interconnect

This is the first-level electrical and mechanical connection formed by solder bump or Cu pillar structures on the substrate interface.

Typical materials: solder alloys, Cu pillar structures, UBM, TCB support materials

Why it matters: this interface sets the pitch constraint, stress path, and route selection for the package.

Underfill and reinforcement layer

After first-level connection, the package usually needs a reinforcement layer to redistribute local stress and improve environmental robustness.

Typical materials: CUF, NCP, NCF, board-level underfills, molded underfill

Why it matters: this layer strongly influences voiding, interconnect crack resistance, and fatigue transfer into the package and board.

Molded package protection

Packages using molded protection or compression-molded reinforcement require EMC selection matched to geometry, filler cut, and warpage target.

Typical materials: low-CTE EMC, thermally conductive EMC, molded package compounds

Why it matters: molded materials can improve protection and heat spreading, but they also strongly influence package curvature and reliability balance.

Lid attach and heat spreader interface

Packages with lids or heat spreaders require bondline materials that support heat flow while maintaining controlled stress and dimensional stability.

Typical materials: conductive lid attach, non-conductive lid attach, TIM1, gap fillers

Why it matters: thermal-path design can improve heat transfer while also changing curvature response and second-level fatigue behavior.

Local encapsulation and protection

Some package designs need local encapsulation, glob-top style protection, or flowable cavity fill materials around exposed or stress-sensitive regions.

Typical materials: encapsulants, cavity fills, UV/moisture protection materials

Why it matters: these materials are used to support local environmental protection, cavity filling, and stress buffering in sensitive package zones.

Functional Material Categories in FCBGA

The solution space should be organized by function rather than by SKU. That makes it easier to connect the application need to the material role before narrowing to a supplier family or product.

Fine-pitch underfill materials

These materials are used to support the first-level interconnect after or during assembly, depending on the route used.

Typical chemistries and families

Capillary underfills, non-conductive paste, non-conductive film, board-level underfills

What usually matters

Viscosity, wetting, cure profile, void resistance, ionic cleanliness, modulus and CTE balance

Molded package materials

These materials are used where package-level protection or molded reinforcement is required, especially in routes that demand profile control or harsh-use robustness.

Typical chemistries and families

Low-CTE EMC, thermally conductive EMC, compression-moldable package compounds

What usually matters

CTE, shrinkage, filler cut, mold flow, moisture behavior, modulus retention, warpage response

Lid attach and thermal interface materials

These materials are used when the package requires a lid, a heat spreader, or a broader system thermal path to external cooling hardware.

Typical chemistries and families

Conductive lid attach, non-conductive lid attach, TIM1, TIM2, gap fillers

What usually matters

Bondline control, conductivity, compliance, cure stress, moisture behavior, interface stability

Key Features

High performance and low cost package solutions
Superior thermal peformance with copper or aluminum lid/heat spreader
Package sizes from 10 mm to 67.5 mm
Pb-free, and Cu pillar as bumps
SMT components on top or bottom side
Multi-die capability

APPLICATIONS

Computing: Memory, CPU, APU, GPU, HDD storage
Network: small cell base station, network storage driven by cloud computing and high speed processors
Comsumer： DTVs, STBs, game consoles and IOT

RELIABILITY

Moisture Sensitivity Level: JEDEC Level 4 or 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.

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

Hysol GR910 Series for BGA and LGA Substrate Packages

The Hysol GR910 series includes epoxy molding compounds positioned for BGA and LGA substrate package designs, with variants tuned for flow, warpage control, finer gap filling, higher Tg, lower stress, and thin factor package requirements.

Product	Key Feature	Application Requirement Where It Is Used
Hysol GR910-C	High fluidity, 75 µm spherical filler, low shrinkage, advanced warpage control	Memory BGA/LGA substrate packages where good mold flow, broad moldability, and established warpage control are required in mainstream package designs
Hysol GR910-C4	Finer 53 µm filler, improved filling in narrow gaps, lower smile warpage, MSL3 @260°C	BGA/LGA packages with tighter gaps or finer geometry, where better cavity filling, lower warpage during PMC/reflow, and stronger moisture-reflow reliability are needed
Hysol GR910-K	High Tg, low stress, controlled shrinkage, high reliability	BGA/LGA packages needing higher thermal stability, lower stress on package structures, and MSL2/3 reliability performance
Hysol GR910-LB	Low stress, high adhesion, low moisture absorption, good reliability for thin factor cards	BGA TF card and thin-profile substrate packages where thin-package integrity, adhesion, low moisture pickup, and dimensional control are critical
Hysol GR910 K-31	High Tg and low shrinkage positioning	Application-specific option when the package needs the GR910-K logic but with stronger emphasis on low shrinkage.

Thermally Conductive Epoxy Molding Compounds for FCBGA, FCCSP, SiP, and Related BGA Packages

These thermally conductive epoxy molding compounds are designed for FCBGA, FCCSP, SiP, and related BGA packages using compression molding. Each EMC grade offers a different balance of thermal conductivity, flow, CTE control, and high‑temperature mechanical strength to support different substrate‑based package requirements.

Product	Key Features	Typical Applications
Hysol GR920‑MR5A	3.1 W/m·°C thermal conductivity, 91% filler loading, 20 µm filler size, high flow, low shrinkage, and low CTE for stable package molding.	FCBGA, FCCSP, SiP, and other BGA substrate packages that need fine‑gap filling, low warpage, and good heat dissipation.
EMC‑G185	3.1 W/m·°C thermal conductivity, 190°C Tg, 20 µm filler size, low CTE, and ion‑catcher design for high‑temperature package stability.	Thermally demanding FCBGA, FCCSP, SiP, and related BGA packages that need higher heat resistance, controlled expansion, and balanced mechanical performance.
EMC‑G186	3.0 W/m·°C thermal conductivity, 91% filler loading, high flow, low CTE, and stronger stiffness retention at high temperature.	Compression‑molded FCBGA, FCCSP, SiP, and related BGA packages that need easier flow, good heat transfer, and stronger mechanical support at elevated temperature.

BGA Lid attach.

Conductive Lid Attach

CE3920
ICP3920
3185
QMI529HT

Non conductive Lid Attach

MC723
3003
3005
3188

BGA Encapsulation

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:

Ball Grid array underfills

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.

Underfills for BGA packages.
In principle most underfills should work for Ball grid arrays but some popular products are: