Electronic Materials Pte Ltd

 . .  your preferred partner-supplier of electronic materials solutions.

Polymer Solutions for

Circuit Assembly

Encapsulation & Potting

Hybrid/Thick Film

Optoelectronic

Semiconductor Packaging Thermal Management Automotive Electronics

EMI Shielding Gaskets

EMI Shielding Tapes

I/O Backplane Gaskets

EMI Shielding Laminates

 

Cyanoacrylate and Anaerobic Engineering Adhesives

Surface Protection, Masking and Specialty Tapes

Conductive Ink for RFID, Flex Circuits, Membrane  Switches, High Density Interconnect

Engineered Films & Papers for Photovoltaic, RFID, Flex Circuit, Insulation, Biomedical

High Tech Metallurgy - Chemically Active Materials

Electrically Conductive, Thermal, Structural Adhesive Films & Preforms

Active Solder Alloy, Join Metal, Ceramic, Glass, Carbon Material Without Plating and Flux

The activation process for S-Bond products is not ultrasonic soldering, which is where a large amount of ultrasonic energy is directed against the surface of the substrate material to break up the oxide surface layer and allow the molten solder to circumvent and interpenetrate the layer to reach the base material. The oxide layer being broken in S-Bond® joining is very thin, is only on the solder material, requires very little energy to be disrupted, and does not remain as part of the bond.

A feature of S-Bond products is that they do not flow or wick into openings like conventional solders. Unless pushed, our materials stay where they are placed. This can be useful in situations where precision joining is required.

Active Solder Technology

S-Bond® Solder Products: How They Work

S-Bond® products work with the addition of titanium and/or rare earth elements to conventional solder alloy bases. These active elements migrate to any interface and react with the opposing material surface to remove oxides and nitrides and transport them into the bulk of the solder as an inert material. This process occurs while the material is molten, and once the thin "skin" that forms on the surface of the molten solder is broken, it allows contact between the bulk solder and the substrate surface. The breaking of this skin is referred to as "activation" and is done by application of a low level of mechanical shearing action at the interface between the S-Bond material and the substrate. The level of shear required is small and can be delivered by brushing or scraping the surface, sliding the joining surfaces relative to one another, or application of high frequency vibration to the parts to be joined. The figures below show two types of mechanical agitation, one is brushing or peening and the other is ultrasonic agitation.

 

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Once the skin layer has been disrupted, the bulk solder reacts almost instantaneously and in the case of a molecular bond, irreversibly with the substrate surfaces, creating a tightly held layer of solder on the substrate. This means that the resulting joint may be disassembled and reassembled simply by re-heating above the melting temperature of the SBT product and then re-joining the parts with some additional activation to insure reaction with the new solder. The bonded layer at the substrate surface will not be affected, so good interfacial bond strength is maintained and re-activation is not required.

S-Bond adheres to surfaces utilizing one of two mechanisms that are shown to the left. the metallurgical mechanism operates with copper and aluminum surfaces when S-Bond  joins at 250C. The active elements in S-Bond alloys enable the reaction of Sn-Ag-Ti with the underlying base metals to produce a metallurgically reacted joint. This process can also operate on many metals be activated at significantly elevated temperatures, normally as a metallurgical pre-treatment, to activate the surfaces for S-Bond joining.

The other joining mechanism that operates at regular joining temperatures (250°C) is one of adhesive joining or attraction of surfaces with opposite "electronic" charges. Since metals such as titanium and stainless steel have very thin 'dielectric' protective oxides such as TiO₂ or Cr₃O_2, they provide an insulator layer that the S-Bond active elements and the elements in the base metals or ceramics attract across as in typical Van der Vaals attractive bonding, as the schematic above illustrates.

S-Bond Solder Alloys

Our materials are modifications of conventional solder formulations that wet and bond without the use of flux. All formulations are lead and cadmium free and conform to the requirements of all lead free solder initiatives (RoHS, etc.). Formulations are available in ingot, wire, foil, pellet, and custom preforms.

* Developmental products with limited availability.

Applications:

Direct Die Attachment.

 

High performance microprocessors need new ideas for thermal management if they are to continue to increase in speed. One option is to improve TIM1 performance through the use of direct die attach using solder materials.

Conventional attachment techniques using filled polymers can't offer the same level of thermal conductivity as a completely metal bond, but directly bonding to silicon and packaging materials typically requires the use of a flux or thin film metallization of the joining surfaces.

SBT offers options for bonding to silicon and metal, ceramic, or ceramic composite materials without metallization or flux which, in some cases, can withstand lead free solder reflow cycles for board mounting.

 

Electronic Packaging:

 

The increased use of new materials for improved thermal management and lower cost is challenging conventional joining processes. SBT products have been shown to bond to silicon dies and MEMS without the need to coat or metallize prior to joining. These materials also join well to copper-tungsten, alumina, silicon carbide, nickel, and other materials used in lids and substrates.

These capabilities offer the possibility for direct die attachment to a package lid, joining of MEMS and other devices into lead frames, and direct attachment of silicon or silicon carbide devices to heat sinks and heat spreaders.

Additionally, in the area of power electronics, S-Bond® materials can be used to bond IGBT modules directly to base plates of copper-tungsten, aluminum silicon carbide, aluminum nitride, and nickel coated versions of these materials.

 

Advanced Thermal Management:

 

The need for light weight, high performance thermal management systems is moving from the traditional military and aerospace applications into industrial and consumer electronics as ever increasing speeds in ever smaller devices call for the use of new materials.

Metal matrix composites such as aluminum silicon carbide, ceramics such as silicon carbide and aluminum nitride, and graphite structures such as pyrolytic graphite and foamed graphite are all being used to improve thermal performance without adding weight.

S-Bond® solders are unique in their ability to give a high performance thermal joint between, and bond to, these materials, as well as to metals like aluminum and copper. Our materials offer approximately 10 times the thermal conductivity of thermal epoxies along with the ability to bond in air without the use of fluxes, and to have a bond that allows rework of damaged parts. Some of the specific applications that can benefit from this are avionics, laser systems, and high performance computers.