Interconnects and Conductive Pastes

Transient Liquid Phase Sintering (TLPS) pastes are lead-free and high-temperature stable sintering solder systems for semiconductor packaging and assembly.


Materials for Semiconductor Packaging & Assembly

We develop and deliver advanced materials for the packaging and assembly of semiconductors and electronics.

From R&D customization to high volume scale up, our rich portfolio of innovative sintering pastes and alternative solder materials and chemistries enable lead(Pb)-free, gold-free, and nano-free packaging solutions for a wide variety of demanding applications requiring high thermal conductivity, high temperature stability, and superior long-term reliability.

At the heart of our business are deep collaborative relationships and an intimate understanding of customer needs. This leads to our unique ability to develop tailored paste metallurgies, chemistries and rheologies to meet a wide range of process window constraints.

Contact us to learn more

  • Asia: packaging-asia@merckgroup.com
  • Americas: packaging-americas@emdgroup.com
  • Europe: packaging-europe@merckgroup.com

What is Transient Liquid Phase Sintering (TLPS)?

Transient Liquid Phase Sintering (TLPS) pastes are similar in form, fit and function to lead-free solder pastes.

However, unlike conventional solder pastes, TLPS pastes comprise a mixture of high melting point metal powders (Cu, Ag, etc.) and lead-free solder powders (SAC305, SnBi, etc.) within an organic flux vehicle. Upon thermal processing above the reflow temperature of the solder powders, the liquid phase alloy reacts with the adherents as well as with the high melting point powders within the paste, driving rapid solidification and the formation of metallurgical connections extending across the bondline.

Since the sintering reaction is assisted by a lead-free solder alloy, the sintering process is achieved using conventional assembly and processing equipment (reflow and/or batch-ovens), and any solderable metallization is suitable. 

High-Temperature Packaging and Reliability

When formulated for high-temperature stability with a lead-free, tin(Sn)-alloy (SAC305 or equivalent), intermetallic formation can be driven to consume the entirety of the solder alloy during the sintering process, rendering a metallurgical network with excellent thermomechanical stability beyond 400°C, far higher than the original melting point of the lead-free SAC solder (218°C) and the peak processing temperature (235°C).

This is shown in in the Differential Scanning Calorimetry (DSC) scan below. Initially, the solder alloy is shown to melt at 218°C, however, after a 5-minute dwell at 235°C, no sign of the initial solder is left upon re-heating.
There is no re-melting. Unlike conventional solder pastes, TLPS materials can undergo additional reflows without re-melting and without change in performance.

350C Die-Shear Test

TLPS pastes retain excellent mechanical performance even at 350C, well in excess of the melting point of most solder alloys.

How Are TLPS Pastes Processed?

TLPS formulations are available in a variety of viscosities and rheologies and can be processed via needle-dispense or stencil-printing. In most cases, best-practices utilized for solder pastes can also be applied to TLPS pastes.

Stencil Printing Process

TLPS pates are processed using standard SMT equipment.

Competitive landscape

  Feature Ormet® TLPS-Paste
Conductive Adhesives Solder Paste​
Ag-sintering

General Property

Process Temperature

190-260℃

120-175℃

190-350℃

200-280℃

Bonding Mechanism

Metallurgical

Adhesive(Chemical bond)

Metallurgical

Metallurgical

Reaction Process

In-line reflow / Box oven

Box oven

In-line reflow

Thermal compression

Sintering pressure

0MPa

0MPa

0MPa

10~30MPa

Thermal conductivity  (W/m.K)

20-60

<10

20-60

>100

Electric Resistivity  (μΩ.cm)

10-50

<100

10-30

<10

Flux Residue

No

No

Yes

No

Will Re-Melt in 2nd Reflow?

No

No (Tg)

Yes

No

Application

Power Die-attach

Baseplate/DBC attach

 

Components attach

 

 

FCBGA

 

 

PCB Z-axis interconnects

 

 

Value proposition for TLPS

  • Processable like Pb-free solder
  • No remelt below 400℃ unlike solder
  • Thermal stability like sintering material
  • Stable electric and thermal conductivity like solder
  • ROHS compliant

Please contact us to learn more about specic product informaiton for TLPS:

  • Asia: packaging-asia@merckgroup.com
  • Americas: packaging-americas@emdgroup.com  
  • Europe: packaging-europe@merckgroup.com

You benefit from

  • World-class purity and ultimate quality
  • Highly reliable batch-to-batch uniformity
  • Local service in the US and Asia
  • The assurance of our global footprint

Contact us

... and talk to a local expert about our products!

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