| Liquid Epoxy Electronic Packaging Materials
------ZKEP series liquid epoxy electronic packaging materials (LEEP), including FC-BGA/CSP underfill and over encapsulants, prepared by mixing of high purity, low viscous, high adhesive epoxy resins with spherical silica filler, and curing agent, catalyst and surfactants, are single component without evolving of organic volatile in thermal curing process, which could be directly used with addition of any other components prior to use.
------FC-BGA/CSP underfill are highly flowable, high purity, one component liquid, suitable for the gap size and solder bump pitch > 25 mm. After thermally cured, a uniform and void free underfill layer under flipchi devices was formed for protecting the active surface of the die while improving the device reliability by distributing stress away from the solder interconnects.
------Several issues should be taken into account before selecting the optimal underfill and encapsulants, because the adhesive features have a big impact on your product performance. The physical properties, such as viscosity, thixotropic index, and working life, and the curing condition will usually influence on the processing of applying the liquid. Glass transition temperature, shear strength and modulus of the cured materials will affect the product performance. It is recommended that the customer should perform a through evaluation for any application based on their specific requirements.
Advantageous Features:
- Single Components, easy processing and handling
- High purity, low impurity
- low stress, low CTE
- Good adhesion to substrates such as Si, GaAS, SiO2, Si2N3, Cu, Al, Ni
- Good storage stability
Typical Applications
- Flip chip underfill for FC-BGA, FC/CSP
- Device Encapsulantion
- Die attach in hybrid microelectronics, semiconductor packaging and assembly
- Quartz crystal attach
- LED attach and interconnetc
Table 1 ZKEP Series Liquid Epoxy Underfills
Products
|
ZKEP4110 |
ZKEP4120 |
ZKEP4130 |
ZKEP4140 |
Components |
Single |
Appearance |
Viscous Liquid |
Viscous Liquid |
Viscous Liquid |
Viscous Liquid |
Absolute Viscosity at25 ℃（Pa.s） |
6-10 |
10-14 |
16-20 |
25-30 |
Filler（wt.％） |
55-65% |
Part Gap/Pitch
Size Filled |
>25 mm |
>35 mm |
>50 mm |
>75 mm |
Pot life |
>12 h |
>12 h |
>12 h |
>12 h |
Storage
Stability |
>6months
(-40℃) |
>6 months
(-40℃) |
>6 months
(-40℃) |
>6months
(-40℃) |
Impurity
（ppm） |
Na＋ |
<3 |
<3 |
<3 |
<3 |
K＋ |
<5 |
<5 |
<5 |
<5 |
Cl－ |
<6 |
<6 |
<6 |
<8 |
Tg (℃) |
100 ℃ |
120℃ |
145℃ |
110℃ |
Moisture
Uptake（％） |
< 0.7 |
<0.6 |
<0.8 |
<0.8 |
Modulus（GPa） |
>8.5 |
>8.5 |
>8.5 |
>8.5 |
CTE（ppm/℃） |
<25 |
<25 |
<25 |
<28 |
Adhesion Strength（MPa） |
≥3.0 |
≥3.0 |
≥3.0 |
≥3.0 |
Note:
1） ZKEP4110 series are high flowable, high purity, one component underfill. A uniform and void free underfill layer could be formed under flip chip devices, protecting the active surface of the die while improving reliability by distributing stress away from the solder interconnects.
2） ZKEP4120 series are low stress underfill formulated for rapidly flowing under 25 um gap and for ceremic or laminate substrates where minimal stress is important
3） ZKEP4130series are low alpha particle emission underfill formulated for rapidly flowing under 25 um gap and for low stress and low modulus applications.
4） ZKEP4140 are low alpha particle emission underfill formulated for rapidly flowing under 25 um gap and for high Tg and low CTE applications.
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