Block Copolymers in Improving Nanolithology

Nanolithography, a type of nanotechnology, is a field constantly improving. Dr. Greg Liu researched nanolithography and gave a seminar on the recent developments. According to Dr. Greg Liu, block copolymers can be used to assist in making extremely small structures. Liu outlined some of the challenges the field of nanolithography is facing, and elaborated on how his research can address these issues.

Despite the clever rhyme of that old adage, bigger is not always better. Much of the technology used today is dependent upon minimizing the size of its components. Reducing the bulk of machines effectively increases production and convenience. The field of nanolithography aligns closely to this ideal. It focuses on the development and application of very small structures, and Liu suggested[a] that his research can greatly benefit the field of nanolithography.

In order to better understand Liu’s proposal, it is important to understand the practical use and problems with the current methods. Over the past several decades, nanolithography has greatly improved microchip technology. Getting lanes on the microchip to carry more information over less space is undeniably ideal. Unfortunately, due to current practices, accuracy and precision exponentially decay with decrease in size. Liu stated that in order to create one of these microchips, the user must be able to identify the microscopic arrays, plant single dots of metal material in each grid, and manipulate the size and shape of each spot.

A popular method of development is with Dip-Pen Nanolithography (DPN). In DPN, a molecular “ink” is deposited onto a base via diffusion through a water meniscus. This was a revolutionary application method in the late 90’s. One of the major obstacles, however, is the fact that the placement of the molecular ink is randomized. At single-digit nanoscale, many metals are inaccurate in where they attach. That is where the block copolymers come into play. Liu’s research suggests that by adding block copolymers, the molecular ink can be much more manageable. A unique copolymer is designed depending on the ink and the desired shape. The copolymer and ink mixture are heated to a temperature that activates the copolymer. The copolymer then arranges itself depending on its nature. The ink is concentrated inside the copolymer, achieving a particular size and shape. The heat is then increased, separating the copolymer and depositing the molecular ink.

The research continues, but there is now strong evidence suggesting that this is a plausible method to be used in nanolithography, which will be a huge benefit to the microchip industry.