Connect with us


What Is A Stepper? What Role Does It Play In Photolithography?

What is a Stepper?

A stepper is a highly precise piece of equipment that is used in photolithography in order to create very small integrated circuits for use in electronic devices and computers. The primary purpose of the stepper is to focus a pattern of light onto a silicon wafer that has been treated with a special photosensitive chemical called a resist. The interaction of the light and the resist allows subsequent chemical developing processes to form actual circuits. At the most basic level a stepper is a very highly calibrated and precise projector. The machine has several different features and functions.

Controlled Environment

All of the work that a stepper performs takes place in a sealed container that maintains a carefully controlled environment. The circuits that are produced have some features that measure less than 100 nanometers across. Even visually unnoticeable expansion or contraction in the silicon wafer due to temperature variations could negatively affect the exposure. The chamber in a stepper is air-conditioned and kept clean of small grains of dust and dirt that could destroy an entire batch of wafers.

Wafers And Alignment

The first phase when using a stepper is to load the silicon wafers into the machine after they have been coated with the resist. The automated systems inside of the stepper accept the wafers from a tray. The first wafer is placed on platform called a stage. The stage is aligned underneath of the light source. The pattern that will be projected onto the wafer is etched in a six-inch square plate called a reticule that could be made from glass or quartz. The reticule is automatically loaded according to the specifications of the program being run. Small registration or alignment marks on the stage and wafer allow for precision alignment just before exposure.


Exposure occurs when the light source inside of the stepper activates. The light passes through the reticule and arrives in a lens. The lens focuses the light and the pattern reducing the size of the projection dramatically. Exposure times vary depending on many factors including the chemicals being used. A single integrated circuit could require 100 or more exposures from many different reticules before the stepper is complete. Additionally, the wafers are normally developed in chemicals, recoated in the resist and placed back into the stepper. Some wafers must pass through the stepper dozens of times before completion.


Most modern steppers actually use a technique known as scanning. The name stepper comes from the step and repeat processes that is performed. Different small areas of the wafer are exposed to the reticule and then the process is repeated for each section. Scanning involves moving the stage holding the wafer in one direction while the reticule and light is moved in the opposite direction. The result is a slit of focused light that allows larger areas to be exposed with a single reticule. Scanning has increased the potential resolution of a reticule allowing for smaller and more precise circuits.
Peter Wendt is a writer & researcher interested in technology and photolithography. Wendt recommends readers go here for information on steppers, scanners, and related topics.

Continue Reading

Recent Posts

Home Improvement3 months ago

How To Add More Value To Your Home

If you have some spare cash in the bank, it is likely you would like to spend it on your...

Lifestyle3 months ago

What is a Deep Plane Facelift

Cosmetic surgery is a choice that needs a lot of research and when it comes to thinking about a facelift...

Entrepreneur3 months ago

Unveiling the Demand for Digital Marketing Courses: A Comprehensive Analysis

In recent years, the realm of marketing has undergone a seismic shift propelled by the digital revolution. As businesses increasingly...

Home Improvement3 months ago

What Does an Effective Wardrobe Spring Clean Entail?

Spring is upon us which means one thing and one thing only. It is time for the annual purge of...

Business5 months ago

Your Basic Guide To Creating A Unique Investment Blog

Starting your own blog is great and once you get the ball rolling, it can be a good passive income...

Business5 months ago

3 Low-Risk Ways To Get Your New Business Started

Once you’ve got an initial business idea and believe that it will be a success, there are some basic things...

Lifestyle5 months ago

Conquering the Co-free Zone: Tips for Thriving as a Remote Worker

Adjusting to an office environment can come with its downfalls in the sense that it might be a shock to...

General6 months ago

3 Ways To Take Control Of Your Finances Starting Now

If your finances have taken over and are bringing stress to your life, we understand just how overwhelming it can...

Travel8 months ago

Best Places To Visit In The North Of England

If you live in England, you will know there are many different places to visit for the weekend. There are...

General8 months ago

Green Home Improvement Ideas

In a world where environmental concerns are growing, the concept of “green” has gone beyond a trendy catchphrase and is...

Lifestyle8 months ago

How to Host an Unforgettable House-Warming!

The time has finally come. You have moved into your dream pad, and are officially adulting in your very own...

Autos8 months ago

A Guide to Parking Lot Striping

The journey to a well-striped parking lot begins with the right paint. In this brief guide, we’ll unravel the mystery...

Business11 months ago

Business Tips For Protecting Your Finances During A Recession

In 2023, taking the necessary steps to protect your finances for your business is now more important than ever. The...

Lifestyle12 months ago

Tips For Cleaning Your Trainers

If you’re into your trainers and streetwear, you’re likely to be very conscious of keeping them looking their best! So,...

Marketing1 year ago

Branding Trends For Start-Ups in 2023

Branding is incredibly important as it impacts how your business reaches and connects with its target market. If you’re branding...