Printing tiny parts on a chip starts with a piece of quartz called a photomask. This clear quartz has a special engraved pattern on it that works like a stencil. Shining light on the photomask etchs the pattern onto the wafer, creating the billions of three-dimensional transistors and wire-like structures that make up a modern chip.
To make a chip, you have to shine different amounts of light on the photomask so that the chip can be produced in several layers. In this way, the number of photomasks used in the chip-making process varies depending on the type of processor, and in some examples it may exceed 100. Nvidia says that each H100 chip requires 89 photomasks to make. Intel uses more than 50 photomasks in making its 14nm processors.
New techniques have been developed that make it possible to etch parts smaller than the wavelength of light used to make them, however, the ever-decreasing size of on-chip parts has created a series of problems in the field of light refraction. Computational lithography prevents effects caused by refraction through complex mathematical operations. As the dimensions of on-chip components decrease, computational lithography requires more processing power.
Computational lithography processing requires a significant number of powerful computers (often tens of thousands of server systems). Even with today’s systems, each photomask can take weeks to build. Of course, the required time has a direct dependence on the complexity of the chip; For example, Intel says it makes each photomask in five days.
Nvidia says that the number of servers required to build a modern photomask is increasing at the rate of Moore’s law, and this has caused the required processing power to enter unsustainable territory. This is where cuLitho comes in handy. cuLitho reduces the time needed to perform computational lithography processes to eight hours.
Chinese companies will not be able to obtain Nvidia’s cuLitho software due to sanctions that have been in place since last year.
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