Solder adhesive, also known as epoxy solder paste, is widely used in SMT precision microelectronic component soldering, semiconductor packaging, chip packaging, LED die bond packaging, FPC flexible products, camera modules, and other fine soldering fields due to its unique advantages. Fitech’s epoxy solder paste products are high-strength soldering products prepared by combining alloy solder powder with excellent sphericity, uniform particle size, low oxygen content, and high strength with halogen-free flux. Only a tiny amount of solvent volatilizes during the soldering and curing process. There is no solder balls formation after soldering. After solder powder melts and shrinks, the solder joints are metallurgically connected. Flux residue becomes thermoset adhesive, strengthening the solder joints, which plays the role of anti-corrosion and insulation. Fitech’s epoxy solder paste products have the characteristics of no-cleaning, anti-corrosion, and high insulation, and are a new type of electronic packaging material. The products cover a variety of alloys with low temperature and medium-high temperature and have categories covering T4 to T10 based on particle sizes, which are suitable for various scenarios.

Fitech's ultra-fine epoxy solder paste products mainly include low-temperature ultra-fine epoxy solder paste, medium, and high-temperature ultra-fine epoxy solder paste, specified epoxy solder paste for micro-LED and anisotropic conductive paste.

Epoxy Solder Paste Soldering Mechanism


Low-temperature metallurgical-connection halogen-free anisotropic conductive paste is used to manufacture touch screens, smart cards, radio frequency identifications (RFID), flip chips, flexible printed circuits (FPC), and other products. It applies to the assembly and packaging of microelectronic circuits with ultra-fine pitch and is accelerating the miniaturization of microelectronic packaging. It is used in soldering on two fine-pitch conductive connection points in the manufacturing process of electronic components to avoid short circuits and improve the product's yields.



FACA-138D series is a low-temperature metallurgical-bonding halogen-free anisotropic conductive paste (ACP). The main alloy component of FACA-138D is SnBiAg0.4. Fitech classifies solder powders into T8 powder (2-8um), T9 powder (1-5um), and T10 powder (1-3um) based on particle sizes. Solder powder and epoxy-based flux are combined to produce a low-temperature conductive paste.


1. The conductive filler has uniform particle size, and FACA-138D has outstanding dispersion performance;

2. After hot-pressing solidification, the bonding of insulated materials increases soldering reliability;

3. There is no solvent volatilization during the hot-pressing curing process;
4. The hot-pressing temperature is low, and the solder powder melts and metallurgically connects with the pad, enhancing the 
bonding strength;

5. FACA-138D is an extraordinary anisotropic conductive solder that is longitudinal conductive and non-conductive in the transverse direction.

ACP Curing Process


Before Curing:

FACA-138D Properties Before Curing

Product Display



1. Warming Instruction: Solder paste needs to be refrigerated, and the preferred temperature is 0-10When taking out solder paste from the cold box, its temperature is much lower than the room temperature. If the bottle cap opens without rewarming, the water vapor in the air will easily condense and adhere to the solder paste. The high temperature exceeding 150 during soldering increases the vaporization rate of water, which may cause the phenomenon of "exploding solder" to produce solder balls and even damage the components.

2. Warming Method: The sealed solder paste should rewarm to room temperature naturally; Rewarm no more than twice.

3. Warming Time: Return to warm for 2 to 3 hours at room temperature. The actual time required to reach thermal equilibrium varies by vessel size.

4. Note: Do not open the bottle cap without sufficient rewarming or shorten the rewarming time by using heat sources.

5. Operating Environment: The best operating temperature and humidity are 20-25°C and 40-60%RH, respectively.

Our engineers will be happy to answer your questions or help you choose the right solder product