Technology in ProductsSemiconductor Lithography Equipment

The Equipment Used to Manufacture the Semiconductor Chips that Support Our Daily Lives and Lead the Way into the Age of the IoT

In the era of the Internet of Things (IoT), all kinds of objects are being connected, from automobiles and smartphones to appliances and game consoles. The demand for the semiconductor chips used in these devices is growing accordingly. The semiconductor lithography equipment that is vital for the manufacture of these chips requires state-of-the-art optical and precision technologies.

December 2, 2021

Overview of Semiconductor Lithography Equipment

Semiconductor lithography equipment is used to perform exposure, part of the semiconductor chip manufacturing process. Semiconductor chips are created by performing exposure of microscopic circuit patterns on semiconductor substrates called "wafers." Semiconductor lithography equipment exposes wafers by using projection lenses to reduce the circuit pattern of an original plate, called a "reticle." This equipment consists of three mechanisms: a reticle stage, a projection optical system comprising multiple lens groups, and a wafer stage.
The reticle on which the electronic circuit pattern has been drawn is placed on the reticle stage. Ultraviolet (UV) light is then shined down through it from above. The UV light that passes through the reticle is relayed through the projection optical system, forming an image of the reticle's electronic circuit pattern on the semiconductor substrate placed on the wafer stage. A resin, called "resist," has been applied to the surface of the wafer in advance. This resist undergoes changes when it is exposed to UV light, so the electronic circuit pattern on the reticle is transferred to the areas on which the UV light shines.

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The Technologies Used in Semiconductor Lithography Equipment

Design, Manufacture, and Control Technologies Used in Projection Lenses that Produce Higher Resolutions

Extraordinary Aberration Control for Achieving Theoretical Resolution Limits

Semiconductor chips are manufactured via reduced image exposure, projecting circuit patterns drawn on plates (reticles) onto wafers. The greater the resolution of the projection lenses, the more delicate the patterns can be, increasing the circuit density.
Lithography equipment incorporates ultraviolet (UV) light sources such as mercury lamps, whose wavelengths include i-line wavelengths (365 nm*), and excimer laser, whose wavelengths include KrF wavelengths (248 nm), alongside high numerical aperture projection lenses. Canon uses advanced optical design technology, lens-polishing technology with nm-level precision, and design, assembly, and adjustment technologies for ultra-high-precision optical system mechanisms to manufacture projection lenses that reach the theoretical limit of resolution. Furthermore, Canon's lithography equipment incorporates a high-precision lens driving mechanism to correct for aberration caused by minor environmental changes during exposure, including atmospheric pressure and temperature changes, thereby producing a high level of resolution.
(*) nm = nanometer, or 1/1,000,000,000 of a meter

High-acceleration, High-speed Stage Control Technology that Improves Overlay Precision and Throughput

Achieving High Resolution and Productivity through the World's Finest Acceleration*¹ and Precision Control Technologies

In addition to circuit pattern miniaturization technologies, Canon's semiconductor lithography systems also rely on key technologies including stage acceleration and synchronization control technologies. Moving the stage at high speed and accurately positioning it helps improve productivity and yield rates, making it possible to mass produce high-performance semiconductor products.
In semiconductor lithography equipment that uses the step-and-scan method*², the wafer stage and reticle stage are continuously moved in sync during wafer exposure. Canon has developed extremely precise synchronization control technology with a sub-nanometer level of positioning precision. The use of technologies such as a special linear motor and a lightweight, high-rigidity stage enables repeated acceleration and deceleration of the reticle stage at accelerations of 12 G or more (1/4 that for the wafer stage), contributing to increased productivity.

*¹ One of the world's highest levels of acceleration
As of August 2018, according to research by Canon.

*² Step-and-scan method
The "step-and-scan method" refers to the use of scan-and-repeat projection by lithography equipment. It is capable of achieving higher resolutions than stepper projection, in which the reticle is secured in place and exposure is performed repeatedly.

Using Big Data Analysis Technology to Support Stable Operation

An AI System that Pushes Lithography Equipment Performance to the Limit

For semiconductor lithography equipment to achieve high productivity and exposure accuracy, it is important to maximize and maintain the performance of its hardware.
To ensure that the diagnosis system used in Canon's semiconductor lithography equipment can accurately detect various events and changes in the status of the equipment, Canon uses high-speed data transfer technology that complies with EDA standards* as well as big data analysis technology that utilizes deep learning and other machine learning algorithms. By quickly collecting and analyzing operation data from lithography equipment, wafer measurement equipment and peripheral equipment, this system can identify changes in equipment status that would be difficult for humans to observe, as well as detect abnormalities and perform prediction and maintenance to achieve the level of operational stability demanded by the equipment industry.

*EDA: Equipment Data Acquisition. EDA standards dictate semiconductor manufacturing equipment standards (SEMI standards) related to data collection.

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