Recently, researchers at the State University of New York come up with a prototype method to make paper circuits that could be processed after only one use. Instead of using the usual metal, resin, and glass components as components, this disposable circuit board is made from a single sheet of paper. Surprisingly, it works with other fully integrated electrical components. After using it (though not specified how long), you can burn it or let it degrade on its own.

They print channels on paper with wax, then melt them until it is soaked in the material. For areas without wax, they printed semiconducting and conductive inks as well as screen-printed conductive metals and gel-based electrolytes. The end result is a thin, flexible piece of paper with a working resistor, capacitor, and transistor on it. When the user no longer needs it, you can burn it to pieces so that nothing is left behind.

Is paper circuits really viable?

While it's too early to tell, I'm going to say that paper circuits are highly viable.

We've been enjoying a wide variety of electronic devices and gadgets over the past few decades, but one consequence of doing so is the creation of a lot of electronic waste, which includes tons of used circuit boards. Most circuit boards and components are not recycled or reused, adding to the continuing bad to the planet.

In order to solve this situation, original circuit board manufacturing industry has been looking for and trying new solutions, and the paper circuit is one of them. Has been regarded as a practical, environmentally friendly, mass-printed circuit board(PCB) product solution.

Research in the past few years has found progress in paper circuit boards by producing transparent cellulose nano papers as flexible PCB substrates. The researchers were able to create a plasma metallization process that converts paper into solderable PCBs. Paper-based technology also allows researchers to print storage devices on wrapping paper substrates, enabling electronic components to be printed on cellulose composites.

Paper Circuits Design

These steps into the future of electronics give us a glimpse into the future of electronics design. Now, PCB manufacturers can develop lightweight, flexible products that include printed intelligence. Additionally, the introduction of paper printed circuit boards to the market allows design teams to emphasize Design for Environment (DfE) principles for single-use electronics.

DfE principles push designers to consider the impact of products on human health and the environment. Taking these principles from concept to reality includes evaluating the chemicals used in the product and the impact of releasing the chemicals when the product reaches the end of its useful life.

The DfE principles also encourage companies to use practices and technologies that do not harm the environment. Researchers have shown that the manufacture of paper circuits has a lower environmental impactthan the production of organic PCBs. Life cycle assessments of paper PCB boards show improvements in reducing or eliminating toxic chemicals that deplete life, deplete the ozone layer and contribute to global warming.

Paper Circuits Properties

In the past, the normal properties of paper caused problems with conductive inks penetrating the pores of the paper substrate and becoming segmented. The sintering process also compromises the stability of the substrate.

A research team has altered the properties of any store-provided paper so that it can be used as a printed circuit board substrate. The change in properties is by applying physical vapor deposition in each manufacturing step to stack conductive structures in the paper without damaging the substrate.

Physical vapor deposition

physical vapor deposition (a) from condensed state to physical vapor deposition. In most cases, the process converts the material into steam by using a high-temperature vacuum or gas plasma. The PVD process then uses a pressure differential to transport the vapor from the low pressure source to the substrate. The final step in the PVD process is to allow the vapor to condense on the substrate, forming a thin film coating.

This method covers surfaces such as paper with a solid conductive material. The design team used several types of conductive materials, including aluminum oxide, to build the memory device's vertical stack of conductive materials. 

Coating a conductive thin film on a substrate can produce memory devices with excellent electrical properties, reproducibility, and stability. While producing a substrate that complies with environmentally friendly design principles, the use of a paper substrate also provides a highly flexible substrate with little degradation.

Plasma Metallization

Another process known as plasma metallization offers promising results, allowing the paper to work as a printed circuit board. Plasma metallization involves high-pressure spraying of powdered conductive metal onto a substrate coated with the silver paste using a plasma showerhead. Once the conductive metal is overlaid on the base material, the hot plasma jet melts the conductive metal, combining it with the silver base to form a highly conductive base.

Initial trials of plasma metallization allowed limited production of flexible printed circuits. This lightweight coated paper substrate costs less than standard polyimide substrates while having good strength and excellent load carrying capacity. The use of flexible base materials opens the door to more creativity for the design team. For example, the researchers note that plasma metallization opens doors for electronic postcards, posters, and packaging.

In addition to physical vapor deposition and plasma metallization, the research team used copper phthalocyanine (CuPc) organic thin films as buffer layers on aluminum tracks printed on paper. The use of CuPC buffer layers and aluminum rails improves the reliability and DfE quality of flexible paper circuits.

Paper circuits could lead to new applications in the future

Research into paper circuit board production techniques continues as researchers work on how to use this technology for larger-scale production. The possibility of producing printed circuit boards that can be folded, trimmed with scissors, or formed into three-dimensional structures could have military and medical applications. 

In industry, the ability to produce very lightweight, biodegradable PCBs leads to microelectromechanical devices including conductive inks, inkjet-printed RFID tags, and sensors, printed integrated waveguides, and other embedded or printed electronic components.

There is no doubt that paper circuits have the potential to change the future of the PCB industry.