Semiconductor Process/Device Structure Inventions – to patent or to keep it a trade secret?

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Semiconductor patents, especially those related to process or device structure technology, are not easy to enforce or monetize. Does this mean companies will be better of terming such inventions as trade secrets?

Patents, by nature, are in the public domain, though they can be legally enforced against infringing products usually over its lifespan of 20 years. Trade secrets, as the name suggests, are secrets and can be kept concealed forever to retain competitive advantage. But they cannot be enforced or monetized if a competitor finds the information legally, say through reverse engineering a product available in the market.

If you look at product datasheets, marketing brochures or whitepapers by semiconductor companies, whether fab or fabless, they rarely disclose details on device structures, manufacturing recipes or material innovations to the level that could provide a competitor with enough intelligence to extract their inventive ideas. Hence, the best and may be the only option for a competitor to obtain intelligence on process/device structure innovations is by reverse engineering a product.

When a semiconductor company is determining whether to patent an idea related to process/device structure technology or maintain it as a trade secret, it might consider the following question:

Can a competitor extract your inventive idea by reverse engineering your product?  

If yes, patent it

Take for instance an invention that encompasses a novel structure for a semiconductor device. This invention enables significant performance improvements and is market-worthy. The crux of this invention involves a back-side image sensor on a silicon-on-insulator substrate with through-silicon-vias built in for interconnections. A competitor can easily determine this invention by reverse engineering the product.

A SEM/TEM (Scanning or Transmission Electron Microscopy) imaging analysis, as well as advanced material analysis such as EELS (Electron Energy Loss Spectroscopy), performed on a product, which could cost say anywhere about ~ $10,000- $15,000 could easily determine the novel device structure the inventor might be selling.

In this case, the obvious answer is to patent the idea as the invention cannot be kept secret from competition. Once patented, an inventor or patent owner can reverse engineer a competitor’s suspected product to determine infringement, thus paving the way for either suing the competitor for damages or licensing the technology and monetizing the patent.

In the midst of this, remember that the potential cost of reverse engineering is also critical. This means that the competitor must consider the expense “reasonable” to spend on acquiring competitive intelligence of an invention. Typically, analyzing material compositions and device structures of semiconductor products may be well within a budget that would be viewed as “reasonable” by a competitor.

If no, consider keeping it a trade secret

If an invention is about a novel process recipe to make an improved device with much higher yields – for e.g., a CVD (Chemical Vapor Deposition) recipe to deposit a thin sacrificial film that is etched off during subsequent process steps and improves yield significantly. In such a scenario, it’s best to keep it a trade secret as it will be impossible for a competitor to reverse engineer the device and determine if a particular sacrificial film was used since the film was etched off and is no longer part of the product.

Remember that if such an invention is patented and a competitor has copied it, it will be equally impossible for the inventor to determine infringement as there will be no clear evidence of use owing to the etching off of the film even from the allegedly infringing product. This procedure could get complicated and expensive. In this scenario, a trade secret is a smarter option of IP protection, bringing with it sustained competitive advantage in the marketplace.

Also, since patents are expensive and filing a patent family in the US could cost a firm tens of thousands of dollars including USPTO and attorney fees, it is good business practice to question if a patent can actually support an offensive/defensive IP strategy effectively. Otherwise, it may be worthwhile keeping the invention a trade secret.


(Featured image is intended for representational purpose alone and has been created by iRunway)

Sreeram Appaswamy
Sreeram Appaswamy

Sreeram is iRunway's Semiconductor expert specializing in product development, supplier management and volume manufacturing strategies. An inventor himself, Sreeram watches the semiconductor industry with a hawk's eye.

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