WACKER SEMICOSIL 988 1K Heat-Curing Silicone Adhesive is a one-component, addition-curing silicone elastomer developed for bonding, sealing, and low-stress protection in electrical and electronic assemblies. Officially designated SEMICOSIL® 988/1K, the ready-to-use, non-slump material combines thixotropic dispensing behavior with rapid thermal curing and primerless adhesion to many compatible substrates. After curing, it forms a flexible, medium-hard silicone rubber that helps protect delicate components from vibration, mechanical stress, thermal expansion, and environmental movement. Typical applications include MEMS die attachment, chip bonding, electronic component fixing, formed-in-place gaskets, cured-in-place gaskets, sensor assemblies, control units, power electronics, and industrial electronic housings.

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WACKER SEMICOSIL 988 1K Heat-Curing Silicone Adhesive Performance

SEMICOSIL 988/1K is supplied as a premixed one-part silicone, eliminating weighing, mixing, and ratio-control errors associated with two-component systems. It cures through a platinum-catalyzed addition reaction after sufficient heat is applied. This controlled curing technology supports sensitive electronic assemblies where dimensional stability, reliable processing, and low mechanical stress are important.

The material is non-slump and strongly thixotropic, retaining bead height after dispensing while shear-thinning through a nozzle. This supports controlled dots, fillets, local encapsulation, and gasket profiles. WACKER states that it can be processed with modern dispensing equipment and recommends considering in-line degassing for air-sensitive applications.

WACKER SEMICOSIL 988 1K Heat-Curing Silicone Adhesive Applications

The product is positioned as a general-purpose electronics adhesive and a sealing material for formed-in-place and cured-in-place gaskets. It can secure chips, MEMS devices, sensors, modules, housings, connectors, and other compatible parts. Its flexibility is useful where rigid adhesives could transfer excessive stress during temperature cycling or vibration.

WACKER also lists SEMICOSIL 988/1K for low-stress MEMS die attachment. Its medium hardness and high elongation help accommodate movement between silicon, metal, ceramic, glass, and engineering plastics. Primerless adhesion is available on many substrates, but results depend on cleanliness, coatings, and manufacturing residues.

7 Benefits of WACKER SEMICOSIL 988 1K Heat-Curing Silicone Adhesive

One-component processing: Requires no metering, mixing, or separate catalyst addition.
Rapid heat curing: Supports short production cycles at qualified elevated temperatures.
Non-slump consistency: Maintains controlled dots, beads, fillets, and gasket profiles.
Low-stress protection: Helps reduce mechanical stress on chips, sensors, and delicate electronics.
Primerless adhesion: Bonds many compatible electronic substrates without a separate primer.
High flexibility: Accommodates vibration, movement, impact, and differential thermal expansion.
Broad electronic use: Suitable for chip bonding, MEMS die attach, FIPG, CIPG, and component fixing.

WACKER SEMICOSIL 988 1K Heat-Curing Silicone Adhesive Properties

WACKER’s electronics product overview lists typical cured properties including approximately 35 Shore A hardness, tensile strength near 4.5 MPa, elongation at break around 350%, and cured density of about 1.1 g/cm³. Gray and translucent versions are referenced in WACKER literature. The recommended maximum continuous operating temperature is approximately 180°C, although actual capability depends on exposure duration, joint design, substrates, and the complete assembly.

Reference heat-cure schedules include approximately 60 minutes at 130°C or 10 minutes at 150°C. WACKER’s current product page states that SEMICOSIL 988/1K performs best when cured at 125°C or above. The required oven time must be adjusted for the thermal mass and heat-sink behavior of the components because the adhesive itself must reach the validated curing temperature.

Surface Preparation and Dispensing Guidance

Bonding surfaces and equipment must be clean and free from cure-inhibiting contamination. Potential inhibitors include sulfur-containing materials, plasticizers, urethanes, amines, and organometallic compounds, especially organotin compounds. Remove processing oils, release agents, migrated additives, dust, and moisture.

Dispense a controlled quantity using compatible volume-time or other validated equipment. For sensitive chip-bonding operations, WACKER recommends avoiding processing conditions that introduce air into the silicone. Preliminary compatibility tests should be completed whenever the substrate, coating, cleaning agent, or adjacent material has not previously been qualified.

Storage, Packaging, and Official Product Resources

For chip-bonding applications, SEMICOSIL 988/1K is available in 30 ml cartridges. WACKER recommends storing these cartridges below 8°C, preferably between 2°C and 8°C, in the tightly closed original package. The closed cartridge should be warmed to room temperature before processing, and WACKER states that its contents should typically be used within ten days after room-temperature conditioning. Larger hobbock packages are stored under different conditions, so users should follow the label for the supplied format.

Review the official WACKER SEMICOSIL 988/1K product page and the official WACKER silicone guide for sensors and ECUs for current technical properties, processing instructions, storage guidance, and product availability.

Explore our heat-curing silicone adhesives for additional one-part and two-part electronic assembly products. Browse our electronic component bonding adhesives for MEMS, sensors, chips, modules, housings, and power-electronics applications.