WACKER Develops Easy-to-Apply Thermally Conductive Adhesive for Electronics Applications
Munich – The Munich-based WACKER chemicals group has developed a thermally conductive adhesive for electronics applications. The new silicone rubber with the trade name SEMICOSIL® 975 TC is characterized by high thermal conductivity and good flow and processing properties. Even light pressure is enough to form an ultrathin adhesive layer between the contact surfaces. This ensures not only good bonding, but also optimum heat dissipation by the heat sink. SEMICOSIL® 975 TC is an ideal interface material for forming thermal and mechanical connections in power electronics components or packages.
SEMICOSIL® 975 TC is an addition-curing silicone rubber that cures at temperatures above 90°C. The one-component adhesive is electrically insulating and adheres to many of the substrates used in electronics. One of its key characteristics is its high thermal conductivity of 4.3 W/mK (as per ASTM D5470). It also offers good processability, despite the fact that it has a high filler content which is necessary to achieve the requested thermal properties.
Before it cures, SEMICOSIL® 975 TC is a very pasty, non-sag material that becomes progressively free-flowing with increased shearing. This property can be precisely adjusted to processing requirements. As a result, SEMICOSIL® 975 TC – unlike comparable previous products – can easily be fed at low pressure, and applied as a bead. It can be processed directly from the pail or from a regular cartridge.
The rheological flow properties of SEMICOSIL® 975 TC also offer advantages for further processing. When a part is pressed in place, the applied silicone forms an ultrathin adhesive layer which conforms to the substrate surface without the need to apply high force. The minimum layer thickness (bond line thickness) that can be applied is between 90 and 100 micrometers, with its usability depending on the design of the interface.
SEMICOSIL® 975 TC is thus ideal for use as a thermal interface material in power electronics. The purpose of such materials is to fix semiconductor devices – such as insulated-gate bipolar transistors (IGBT) – in engine control units and LED components on heat sinks in order to dissipate the heat. Without heat dissipation, the service life of electronic devices would be considerably impaired.
As a thermally conductive adhesive, SEMICOSIL® 975 TC reliably couples the electronic component to the heat sink. The adhesive layer compensates for microscopic irregularities in the surfaces, thereby maximizing the contact area and – thanks to the product’s high thermal conductivity – optimizing heat dissipation.
The new thermally conductive SEMICOSIL® 975 TC silicone adhesive from WACKER is applied to the heat sink. As the electronic component is pressed on, the adhesive forms a thermal interface (TIM). The adhesive layer transfers the heat of the device efficiently to the heat sink. Tightly packed semiconductor components, such as IGBTs, in motor controllers and LED packages can become very hot. Such components are mounted on heat sinks to prolong their lifetime. The new thermally conductive SEMICOSIL® 975 TC silicone adhesive from WACKER bonds the parts mechanically and ensures optimum heat transfer.
For further information, please contact:
Wacker Chemie AG
Media Relations Information
Florian Degenhart
Tel. +49 89 6279-1601
Fax +49 89 6279-2877
florian.degenhart@wacker.com
The company in brief:
WACKER is a globally-active chemical company with some 16,000 employees
and annual sales of around €4.48 billion (2013).
WACKER has a global network of 25 production sites, 21 technical
competence centers and 52 sales offices.
WACKER SILICONES
Silicone fluids, emulsions, rubber and resins; silanes; pyrogenic silicas;
thermoplastic silicone elastomers
WACKER POLYMERS
Polyvinyl acetates and vinyl acetate copolymers in the form of dispersible
polymer powders, dispersions, solid resins and solutions used as binders for
construction chemicals, paints and coatings, adhesives, plasters, textiles and
nonwovens, as well as for polymeric materials based on renewable resources
WACKER BIOSOLUTIONS
Biotech products such as cyclodextrins, cysteine and biologics, as well as fine
chemicals and PVAc solid resins
WACKER POLYSILICON
Polysilicon for the semiconductor and photovoltaic industries
Siltronic
Hyperpure silicon wafers and monocrystals for semiconductor components
Wacker Chemie AG
Hanns-Seidel-Platz 4
81737 München, Germany
www.wacker.com
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