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What is Kapton PCB ?

What is Kapton

It is a general definition that Kapton is a polyimide. Now for a better understanding of Kapton, you need to understand what is polyimide? When dianhydride and diamine monomers react under condensed conditions, then polyamide is formed. A covalent bond of nitrogen is present with two carbonyl groups in polyimide. The two bonds of the nitrogen and carbonyl group are known as the imine group. Polyimide plays a vital role in a wide variety of application due to high rate of strength and stiffness, high range of operating temperature and inert chemical behavior.

Nowadays, whenever engineers are dealing with harsh applications with a high range of temperature and extreme rate of strength and stiffness, polyamides are preferred to be used there. Several electronic devices, LCDs, gas separations, weapon industries, aerospace industry, and high-temperature polymers are using polyamides.

DuPont in 1960 developed Kapton and the specification of Kapton is it remains stable or in isolation under wide ranges of temperature. That’s the reason it has been used in many devices and printed circuits mainly.

Kapton is a highly conductive polyimide, that’s why it is widely used in electronic devices. The main purpose of using Kapton is to control the heat in electric devices such as Kapton can be a good choice if we need a thin, lightweight, and uniform heater. This lightweight, uniformed nigh temperature performance is required by automotive interior heating, wind turbine, and temperature regulation in aerospace. So polyimide conductive film of Kapton can benefit all of them.

Characteristics of Kapton:

Kapton can be used on extremely high and low-temperature ranges. Kapton can maintain extraordinary mechanical, electrical, and physical properties in the wide range of -452 to 752 Fahrenheit. Kapton is a good resister and an effective insulator so it is a good choice for demanding application industries such as electric applications and aerospace. Below is mentioned some useful features if Kapton:

  • It is highly effective
  • It is highly stable in high ranges of temperatures
  • It can tolerate extreme levels of both heat and cold
  • It possesses excellent mechanical, physical, and electric properties which make it an excellent choice for demanding industries
  • It is well suited for diverse applications
  • It has excellent radiation and chemical resistance
  • It provides reliable labeling

What is Kapton PCB?

Printed circuit boards (PCBs) are the ones in which conductive pathways like tracks and traces laminated with copper are used to support and connect electronic components mechanically. So basically printed circuits boards are designed to support pathways in electronic devices. Every single electronic device consists of printed circuit boards because this is the way of transferring signals within an electronic device.

Once you have understood simple printed circuits, then there comes flexible printed circuit boards. You can make your requirements of interface and depend upon your requirement the flexible printed circuit can be made using polyamide such as Kapton as a base material. A flexible printed circuit board is the further type that is made by using a thin layer of the polymer film (i.e. Kapton) with a conductive pattern of traces on the substrate. So we can say that Kapton is responsible for the flexibility of the printed circuit boards.

Flexible circuits were introduced many years ago, somewhere after the Second World War and the industry is still determined to grow these circuits more potentially. Electric devices often face the harshest temperatures that can go beyond levels. The device may be destroyed if the right material has not been used in it. For overcoming this issue, a polyimide should be used that can withstand increasing temperature conditions. Since 1960, Kapton is the best choice for this problem.   

The main reason for using Kapton in electric devices is heat exposure. As we already know that heat exposure so a common risk in manufacturing electric devices and printed circuit boards also. Temperature can go beyond 400 Fahrenheit. So Kapton is a flame retardant and can expose heat up to 700 Fahrenheit not affect the appearance and performance of the label. Kapton is a highly versatile polyimide material and can withstand severe conditions to offer effective circuit board labeling every time.  

Flexible PCBs can vary from single layer to double layer. But the base layer of polyimide Kapton will be present in every type of printed circuit board.

Single-sided Printed Circuit Board:

Single-sided flexible circuits are the most common and basic flex circuits available in the market. There is a single layer of metal traces on one side of the dielectric. The base layer consists of Kapton polyimide, copper foil, and adhesive supporter. While on the other side like a typical printed circuit board, there is a solder mask sheet and area of connection.

Double-sided Printed Circuit Board:

There are multiple layers on both sides of a single dielectric circuit. There are metalized holes between two layers for plating purposes. On both sides of single dielectric, there are multiple layers for connection, overly, polyimide Kapton and other essentials.

Multi-layer Printed Circuit Board:

There are several layers of copper separated by dielectric layers. These metal layers are then connected by plated holes for making interconnections. Multilayer printed circuit boards are more complex and have complex layers of surface mounting.

Rigid Printed Circuit Boards:

In rigid-flex circuits, the epoxy film is used for connecting multiple layers of printed circuit boards. The component density is higher in these circuits.

Advantages of using Kapton PCB

Kapton printed circuits are serving in many fields. The flexibility of the Kapton circuit boards is the basic requirement for many electronic devices. Following are the advantages of using Kapton printed circuit boards:

  • Kapton printed boards are designed in such a way that they can meet higher and smaller density mountain designs and can improve flexibility. Kapton helps in decreasing the assembly process and reliability can be increased through it. Miniaturization and signals flowing in electric devices can only be improved by Kapton printed circuit boards.
  • There is a thick polyimide film on the substrate of the circuit including a copper foil. For thin and light circuits or compact and complex devices, the solution is ranging through single base Kapton circuit to multilayer or 3D Kapton printed circuit boards. The additional mechanical stability and strength can be enhanced by reinforcing the base material of the circuit. In this way, the strength of the circuit would also be increased.  
  • As clear from the name, the Kapton circuit is having flexibility so it can be bend, move, and torsion effect also. And the conductivity would not be damaged by this flexibility.
  • Due to flexibility, Kapton circuits provide excellent electric performance. There is a good flow of electric signals due to the low dielectric constant. After heat exposure, components can be cool immediately because of good thermal properties. Moreover, components can operate very well under extreme temperature ranges because of higher glass transitions.
  • The other main advantage of using the Kapton printed circuit board is, you can reduce the size of the circuit boards which is required by many applications. Smaller size and lower weight is demanded by many electronic devices such as laptops, computers, military pieces of equipment, aerospace, PDAs, peripheral devices, digital devices, mobile communications, and many other fields also.

Why we rely on Kapton polyimide in our PCB?

It is a fact that Kapton polyimide printed circuit boards are designed to use on specific occasions so you need to know when you can use them and when you should avoid them. The purpose of designing Kapton polyimide circuits was to improve the stability and felicity of the circuit in the reduced weight and size. So following are some reasons we tend to rely on Kapton printed circuits most rather than regular circuits.

Stability of thermal power:

As we already know that polyimide material has excellent resilience and thermal stability which makes it more reliable than any other material. This excellent factor of polyimide material helps in dealing with temperature exposures of electronic devices. Due to Kapton polyimide, electronic devices can work in high temperatures such as under 260 degrees. Moreover, the high stability of thermal power prevents the devices from damages while working and repairing also.

Higher flexibility:

The other greatest benefit of Kapton polyimide circuit boards is their extreme flexibility and stability at the same time. Due to this property, Kapton printed boards can be moved and bend easily. This is the perfect match of flexibility and rigidity in one printed circuit board which normal boards are lacking.

Highly endurable:

Kapton polyimide has a higher level of resistance against temperature and many other chemicals which makes it high durability. This ability is essential for dealing with extreme physical stress.

Final Thoughts

So as a conclusion, we can say that Kapton printed circuits are providing the following key points:

  • Greatly reduced in size and weight
  • More efficiency
  • High integration of components
  • Better wire connection
  • Moving and bending reliability
  • High density
  • High reliability
  • Miniaturization
  • Overall low cost
  • Good solderability
  • Excellent heat dissipation
  • Increase in repeatability
  • Thermal management
  • Improvement in aesthetics
  • Demands for heavy electric devices