Stepper machines are used by ‘foundries’ to manufacture integrated circuits – the tiny chips at the heart of our hi-tech equipment.

It’s the lynchpin of photolithography, a process that literally prints with light the pattern of the nano-scale circuits on groups of ‘silicon chips’ on a wafer. This is exacting work carried out in dust-free lab conditions.

Similar to a powerful photographic enlarger, it uses sensitive lenses to focus a pattern onto a silicon wafer. How much the surface is exposed to light determines how much of it remains, as it is developed in solvents in a process that is similar to developing a photographic film, but in three dimensions.

The wafer is then cleaned, recoated with the photo-resistant coating and passed through the stepper again to create the microscopic integrated circuits, layer by layer, step by step.

Unlike consumer electrical devices, stepper machines are made to order. These are extremely expensive pieces of equipment, so manufacturers, such as Nikon, only manufacture the machines when they get requests from the integrated circuit foundry customer.

The manufacturing process can take years from order to fulfilment. We illustrate the process step by step, below.

Prepping for transport

Nikon technicians prepare the steppers for transportation, dismantling and packing them in a dust-free room. Even then, the main body of the equipment still weighs 10 tonnes. All parts are packed to ensure they’re not susceptible to moisture or vibration.

Transport to airport

The packed steppers are transported to Tokyo Narita airport in temperature controlled trailers which also have specially designed shock absorbers to protect the sensitive equipment from excess vibration.

At the airport

Unloading from the temperature controlled trailer and transferring the crates to ULDs is carried out from 4am. Cathay Pacific has a set of strict standard operating procedures for handling stepper equipment, from storage temperature to clear labelling so people recognise the delicacy of the consignment and how it’s handled (for example, maximum forklift speed of 5km/h).

Onboard and inflight

Normally, stepper consignments go on the morning B747 freighter service at 8:20am. For the flight, the temperature inside the hold is set to 23oC. Nikon holds regular briefings with airlines for stepper handling. Cathay Pacific is one of four airlines approved to ship its equipment.

Transit storage in Hong Kong

On arrival in Hong Kong, the equipment is moved to Cathay Pacific Cargo Terminal’s Stepper Room, built exclusively for stepper storage. When the flight to the target country is ready, the equipment is taken from the Stepper Room and loaded on to the aircraft for the next leg of its journey.

Arrival at final destination airport

On arrival at the destination airport and to minimise transportation risks, the consignee seeks permission from the airport authority for a temperature-controlled trailer to come into the ramp area, ideally next to the aircraft, to reduce the distance between the pallet breakdown and the truck.

Final delivery 23°C

After all the pieces are transferred to the trailer, the truck heads for the consignee’s factory. On arrival, the stepper machine crates are transferred to the clean room for unpacking and assembly by Nikon engineers. The stepper machine is then ready to start producing integrated circuits.