Underfilling of Henkel / Underfill materials from Henkel - types and possible applications

Henkel offers various types of underfillings to extend the service life of electronic assemblies. In the following article, you can find out which underfill solutions are available and what they are used for.

What are underfillings used for?

Underfillings are used in particular to reinforce electronic assemblies, enabling them to withstand higher loads. Underfillings from Henkel are used in the production of CSPs, BGAs, LGAs and WLCSPs as well as other components. In printed circuit boards, for example, underfillings are used to reinforce the solder joints between a chip and the circuit board. In addition to the purely mechanical protective effect, the solder joints are also protected during temperature changes.

Underfilling reduces stresses and mechanical fatigue. In addition to performance, this can also increase the service life of the products.

But it is not only the electronics industry that relies on underfillings from Henkel. Other sectors do too, including the automotive and aviation industries.

Types of underfillings

Essentially, there are the following differences in Henkel’s underfillings:

Reprocessable capillary flow underfillings
non-reprocessable capillary flow underfillings
Composite edge underfillings
Corner composite underfillings

This video clearly illustrates the different types of underfill from Henkel.

Henkel Automotive Electronics Underfill Video

Reworkable capillary flow underfill / Reworkable Underfill

An overview of the various reprocessable capillary flow underfillings from Henkel can be found in the following table:

Product	Viscosity	Curing	Coefficient of thermal expansion (ppm/ °C)	Glass transition temperature (_Tg/ °C)
			Under _Tg Over _Tg
LOCTITE ECCOBOND UF 3800	375 cP at 1000 ^s-1	8 min. at 130 °C	52 188	69
LOCTITE ECCOBOND UF 3808	360 cP at 1000 ^s-1	8 min. at 130 °C	55 171	113
LOCTITE ECCOBOND UF 3810	394 cP at 1000 ^s-1	8 min. at 130 °C	55 171	102
LOCTITE ECCOBOND UF 3811	354 cP at 1000 ^s-1	10 min. at 130 °C	61 190	124
LOCTITE ECCOBOND UF 3812	350 cP at 1000 ^s-1	10 min. at 130 °C	48 175	131
LOCTITE 3517M	2600 cP at 36 ^s-1	5 min. at 120 °C	65 191	101

Overview of reprocessable capillary flow underfillings from Henkel

LOCTITE ECCOBOND UF 3810 reworkable capillary flow underfill was developed for CSP and BGA applications and has a higher _Tg value compared to LOCTITE ECCOBOND UF 3800 underfill. The LOCTITE ECCOBOND UF 3810 underfill c ures quickly even at moderate temperatures. This minimizes the stress on other components. The underfill is halogen-free and compatible with most lead-free solders.

After the underfill has hardened, the material has excellent mechanical properties to protect solder joints during temperature changes.

The LOCTITE ECCOBOND UF3810 underfill is available in various pack sizes, also in the abovo online store:

Non-Reworkable Capillary Flow Underfill / Non-Reworkable Underfill

Product	Viscosity	Curing	Coefficient of thermal expansion (ppm/ °C)	Glass transition temperature (_Tg/ °C)
			Under _Tg Over _Tg
LOCTITE ECCOBOND FP4526	4700 cP at 10 rpm	15 min. at 165 °C (heat sink or heating plate)	33 101	133
LOCTITE ECCOBOND FP4530	3500 cP at 20 rpm	7 min. at 160 °C	46 150	145
LOCTITE ECCOBOND FP4531	10’000 cP at 20 rpm	7 min. at 160 °C	28 104	161
LOCTITE ECCOBOND E 1172 A	17’000 cP at 5 rpm	6 min. at 135 °C	27 85	135
LOCTITE ECCOBOND E 1216M	4000 cP at 20 rpm	10 min. at 130 °C	35 131	125
LOCTITE 3517M	5000 – 12’000 cP at 20 s-1	7 min. at 150 °C	35 110	130

Overview of non-reprocessable capillary flow underfillings from Henkel

LOCTITE ECCOBOND FP4531 non-reprocessable capillary flow underfill is designed for flex applications using flip chip technology where a 1 mil (25.4 µm) gap is present. This underfill is fast curing, fast flowing and meets NASA outgassing requirements. The LOCTITE ECCOBOND FP 4531 underfill is available in various pack sizes, also in the abovo online store:

LOCTITE ECCOBOND E 1216M non-reworkable capillary flow underfill is designed for high volume assembly operations requiring a very fast flowing underfill that cures in a single reflow cycle. The underfill is characterized by its excellent stability during shipping as well as during storage and use.LOCTITE ECCOBOND E 1216M underfill is available in various pack sizes, also in the abovo online store:

55 cc
3 0 c c

LOCTITE 3563 non-reworkable capillary flow underfill is fast curing and fast flowing. It was developed for use with packaged ICs, CSPs and BGAs. The flowability of the underfill allows penetration into gaps of up to 25 µm. After curing, it reduces induced stresses at the solder joint. This improves performance during thermal cycling. LOCTITE 3563 underfill is available in various pack sizes, also in the abovo online store:

3 0 cc
10 cc

Edge bond underfill / Corner bond underfill

The following table provides an overview of Henkel’s various composite edge underfillings:

Product	Viscosity	Curing	Coefficient of thermal expansion (ppm/ °C)	Glass transition temperature (_Tg/ °C)
			Under _Tg Over _Tg
LOCTITE 3128	35’000 cP at 5 rpm	20 min. at 80 °C	40 130	45
LOCTITE LOCTITE 3128NH	35’000 cP at 5 rpm	20 min. at 80 °C	40 130	45

Overview of composite edge underfillings from Henkel

Eckverbundunterfüllungen / Edge bond underfill

The following table provides an overview of Henkel’s corner composite underfill:

Product	Viscosity	Curing	Coefficient of thermal expansion (ppm/ °C)	Glass transition temperature (_Tg/ °C)
			Under _Tg Over _Tg
LOCTITE 3508NH	70’000 cP at 36 s-1	Lead-free profile at 245 °C	65 175	118

Overview of the corner composite underfill from Henkel

New Henkel underfill for high operating temperatures

The LOCTITE ECCOBOND UF 1173 underfill is a relatively new product from Henkel that has been developed for high operating temperatures. It is intended for use in CSP and BGA housings and is characterized by its uniformity and void-free properties. The underfill increases the thermal shock resistance of the respective component and thus the reliability of the solder joints. The glass transition temperature is 155 °C and the coefficient of thermal expansion is low.

In addition, the product does not contain any SVHC or CMR substances that would have to be declared under the REACH regulation. This is intended to improve occupational health and safety. The LOCTITE ECCOBOND UF 1173 underfill can also be purchased from the abovo online store in pack sizes of 10 cc and 55 cc.

Henkel’s Underfill Selector

With the Underfill Selector from Henkel, you can find the right underfill product. The Underfill Selector is a selection tool that allows you to specify what you want to use the underfill for and what properties it should fulfill. Suitable underfills are then suggested.