Anisotropic Conductive Film | ACF Interconnect

Anisotropic conductive film ACF or ACF Film/ tape is an epoxy / acrylic adhesive system used by electronics industry. This film creates the electrical and mechanical connections from drive electronics to substrates.

ACF (Anisotropic Conductive Film) is commonly used to make electric interconnection between Flexible circuits or ICs on to a wide range of substrates. Examples of substrates include PCB boards, ITO glass and Flexible circuits. The ACF is designed with insulation between adjacent circuits and strong adhesion to the substrates. Compared to traditional interconnection solutions, ACF bonding method offers high production productivity, cheaper and enables for fine-pitch compact design.

The conductive particles in the film provides electrical interconnection between pads through the film thickness (z-direction). These particles are spaced far apart thus not electrically conductive in the plane direction (X&Y) of the film (No shorting)

This interconnection allows low height and fine pitch allowing high density and small area of assembly.

Besides, the conductive particles are made from environmental friendly material (RoHS compliance). It also provides good metallic bonding.

In short, ACF interconnect is cheaper to implement than conventional mechanical connectors or manual soldering interconnect.

ACF Anisotropic Conductive Film

ACF Anisotropic Conductive Film - Interconnect Applications :

Film/Flex/FPC on PCB. For : PCB, Camera Module, Fingerprint Recognition Module 


Film/Flex/FPC on Glass. For : small/ Medium/ Large LCD panels,


Fine pitch interconnection between 2 layers of PI film.


Chip on ITO Glass. For fine pitch interconnection of min. 6um gap and bump area of 800um2


Chip on Board/PCB/ FR4/ Ceramic. For min. bump area of 1,500um2

For Touch-panel film type or Glass type. High adhesion to plastic substrate.

How ACF (Anisotropic Conductive Film) Works ?

ACF bonding is a mechanical process of applying precise control of heat (temperature) & pressure on to chip (FPC/IC) for a specific set time.

During the bonding process, heat and pressure causes the
adhesive to flow and to bring the circuit pads into contact
by locking and compressing the conductive particles. The adhesive rapidly cures within seconds.

Conductive particles (usually each 3~30um) are compressed between  2 substrates (IC/ ITO glass / PCB /FPC) while insulating materials are pushed away.

This allows the compressed Ni-Au layer on the particles to conduct electricity between the electrodes (z-axis).

The insulated particles are uniformly distributed with a minimum chance of electrical shorting in the x-axis and y-axis.

As the epoxy /acrylic cures, conductive particles are trapped into permanent compressed form.

The compressed particles, by its elastic nature, are constantly pushing outwards to maintain good electrical conductivity under different environmental conditions.

Anisotropic Conductive Film ACF_bonding
ACF particles deformation

ACF Bonding Process Steps

  1. Substrate Cleaning
  2. ACF Pre-attach / Pre-bond
  3. Remove Cover Film
  4. Alignment of Substrates
  5. Main/ Final Bonding
  6. End of ACF Bonding Process