Of all the processes involved in the manufacture of an integrated circuit, photolithography is largely responsible for the deficit in which we have been mired for more than two years. We don’t say it; It is defended by Ignacio Mártil de la Plaza, Ph.D. in Physics and Professor of Electronics at the Complutense University of Madrid semiconductor expert and advanced technologies in solar cells with whom we had the opportunity to speak at length in January 2021.
In one of his interesting articles Ignacio gives us a clue very important about the impact that photolithography has on the production of chips: approximately 50% of the time that it is necessary to invest in the manufacture of an advanced integrated circuit is monopolized by the photolithographic process, and 30% of its cost comes precisely from this stage of the manufacturing cycle. These figures allow us to identify very precisely the relevance of photolithography for the semiconductor industry.
What is surprising is that, despite its indisputable importance, the technology involved in the photolithographic process of high integration circuits is in the hands of very few companies. The queen in this area is ASML, the Philips-owned Dutch company that designs and manufactures photolithographic equipment used by most semiconductor producers in their facilities. In fact, TSMC, GlobalFoundries, Intel and Samsung, which are four of the biggest chipmakers, are their clients.
Manufacturing a high-integration chip is very complex (and is in very few hands)
The purpose of this article is not to delve into the technology involved in the photolithographic process, but before proceeding further it is in our best interest to briefly review what does it consist of this phase of chip manufacturing. Broadly speaking, during photolithography, the silicon wafer is subjected to a process of cleaning, oxidation, coating with photoresin, and, finally, the previously treated silicon substrate is exposed to a necessary mask to define on it the elements that are going to be constitute the chip.
Both these steps and the ones that need to be undertaken next must be carried out in rooms known as clean rooms because they incorporate ventilation systems designed to filter a large part of the tiny particles suspended in the air. If one of these particles were to deposit on the silicon wafer during handling, it would irreversibly damage the integrated circuit that is being ‘etched’ on that portion of the material.
Only a few companies have the necessary photolithographic equipment to produce the most advanced chips
Currently only a few companies have the necessary photolithographic equipment to produce the advanced chips that we can find inside our mobile phones and computers, as well as in other devices that also benefit from the capabilities of the most sophisticated integrated circuits. To the companies that I have mentioned a few lines above are added others such as the Taiwanese UMC or the Chinese SMIC, but this list is very short. So short that at the moment the semiconductor manufacturers continue to be overwhelmed by demand.
However, there is still one more ingredient that we cannot ignore if we want to understand why photolithography is the real bottleneck that grips the semiconductor industry: the chips involved in the manufacture of photolithographic equipment used by TSMC, Intel, Samsung and the other semiconductor manufacturers are also scarce.
Peter Wennink, the CEO of ASML, predicts that chip production will continue to fall short of demand for at least the next two years due to the challenges faced by manufacturers, who have little room to increase their performance. plus. And Pat Gelsinger, the CEO of Intel, It has been recognized recently that the demand and supply of integrated circuits will balance in 2024, a year later than originally planned. We can only cross our fingers and hope that in two years at most the outlook will improve perceptibly.
Cover image: TSMC
More information: Ignatius Martil