Electrically conductive adhesives
Electrically conductive adhesives play a key role in PCB assembly and electronic applications. This is due to their unique ability to electrically interconnect while improving reliability, thermal performance and structural bonding. The market for electrically conductive adhesives is estimated to grow up to 8.4% by 2028.
What are the advantages of electrically conductive adhesives?
The advantages of electrically conductive adhesives include:
- They reduce the number of processing steps, thus reducing costs,
- They polymerise at low temperatures,
- Low thermal stress,
- They do not contain lead,
- They help reduce assembly dimensions,
- They improve the fatigue strength of solder joints,
- Can be adapted and reworked to meet application-specific requirements, such as cure temperatures,
- Compatibility with a variety of substrates, including non-weldable materials.
How do I choose an electrically conductive adhesive for a PCB application?
Before choosing an electrically conductive adhesive, it is important to consider several factors, including:
- Compatibility with the substrate material,
- Operating temperature of the application,
- Humidity levels,
- Chemical exposure,
- Thermal conductivity of the adhesive,
- Adhesive flexibility,
- The method of cure required.
Matching these specifications with those of the chosen adhesive will ensure the best performance.
How is electrical conductivity achieved?
Electrically conductive adhesives are generally available in two different forms: isotropic (ICA) or anisotropic (ACA).
Isotropic conductive adhesives contain a high load of metal fillers and are conductive in all directions. They are commonly used as solder substitutes in surface-mount assemblies,
Anisotropic adhesives contain a lower concentration of metallic filler materials and only conduct in one direction. They are commonly used in flip-chip technology and liquid crystal displays (LCDs).
Most conductive liquid adhesives use chemical epoxy or silicone compounds. Epoxy compounds can be used in high-temperature applications, often 150 °C or more. Silicone adhesives are used in high-temperature applications up to 260 °C and can withstand slightly higher temperature conditions.
What are the different types of electrically conductive adhesives?
Electrically conductive adhesives are generally available in two different forms: isotropic (ICA) or anisotropic (ACA).
- Isotropic conductive adhesives contain a high load of metal fillers and are conductive in all directions. They are commonly used as solder substitutes in surface-mount assemblies,
- Anisotropic adhesives contain a lower concentration of metallic filler materials and only conduct in one direction. They are commonly used in flip-chip technology and liquid crystal displays (LCDs).
Most conductive liquid adhesives use chemical epoxy or silicone compounds. Epoxy compounds can be used in high-temperature applications, often 150 °C or more. Silicone adhesives are used in high-temperature applications up to 260 °C and can withstand slightly higher temperature conditions.
How is the electrical conductivity of an adhesive measured?
Typically, electrical conductivity is measured in ohms per centimetre (ohm-cm). This measures the intrinsic resistance of a material to the flow of electric current. A highly electrically conductive adhesive will have a low ohm-cm value, while a less electrically conductive adhesive will have a higher ohm-cm value.
Does electrical conductivity vary with curing temperatures?
In general, the higher the curing temperatures, the higher the electrical conductivity and mechanical properties of the adhesive. This is due to a denser and tighter cross-linking of the adhesive.
What conductive adhesives does MD Poland offer?
MD Poland offers a range of conductive adhesives for a wide variety of industries and applications. These include our range of heat dissipation materials, electronic shielding solutions, electronic adhesives and sealants and electronic encapsulants. In addition to being a leader in electronic shielding solutions, our team has over 40 years of experience in supporting electronics manufacturers at all stages of the production process, from PCB assembly to full device production.
