Patent on memory chip not completely anticipated by prior art. MICRON v. NORTH STAR

A patent grants its owner the exclusive right to make, use, sell and import the invention claimed in the patent. A patent is granted to the inventor of a new, useful and not obvious invention. To be granted a patent in the United States an inventor must submit a patent application to United States Patent and Trademark Office. The patent application will be reviewed by an examining attorney at the United States Patent and Trademark Office. One of the primary jobs that an examining attorney performs is to review prior art. Prior art is information that has been made available to the public in any form before a given date that might be relevant to a patent’s claims of originality.

If an invention has been described in the prior art (anticipation 35 U.S.C. 102) or would have been obvious over what has been described in the prior art (obviousness 35 U.S.C. 103) , then the examining attorney will give the patent applicant an opportunity to amend the patent application. If no relevant prior art is discovered or the patent applicant is able to modify the patent application to avoid the prior art to satisfaction of the examining attorney then the patent can be granted.

Once a patent is granted, the patent is not immune from review. If a member of the public discovers prior art which would anticipate or render a patented invention obvious, that member of the public can request an inter partes review. Inter partes review is a trial proceeding conducted at the Patent Trial and Appeal Board to review the patentability of one or more claims in a patent only on a ground that could be raised under §§ 102 or 103, and only on the basis of prior art consisting of patents or printed publications. Institution of an inter partes review is not automatic, a petitioner must demonstrate a likelihood they would prevail with respect to at least one claim challenged. The evidence that can be submitted is limited to patents or printed publications which would qualify under §§ 102 or 103 and expert testimony to explain those publications. At the conclusion of an inter partes review the Board may invalidate all, some or none of the claims of the patent.

MICRON TECHNOLOGY, INC. v. NORTH STAR INNOVATIONS, INC. 20-1303 (C.A.F.C. 2021) is an example of a case where the prior art was not found to completely anticipate the claims of a patent.

The technology at issue in this case involves integrated circuit memory chips. The chips at issue are found in the section of the memory known as the “output stage,” which sits between the data storage cell arrays, and the input/output pins that communicate with components outside of the memory.

Respondent in this case owns U.S. Patent No. 5,943,274 (’274 patent), entitled, “Method and Apparatus for Amplifying a Signal to Produce a Latched Digital Signal,” relates “in general to a method and apparatus for amplifying a signal to produce a latched digital signal, and more particularly to an output stage of a memory.” The patent teaches that the prior art uses two clock signals to control memory functions, this can lead to problems when the two clocks get out of sync. The invention teaches how to accomplish the same function using a single clock signal.

Petitioner requested inter partes review of the ’274 patent on multiple grounds, including that the patent is anticipated by Tachibana. The Patent Trial and Appeal Board determined that Tachibana disclosed a large number of the claims of the ’274 patent however Tachibana failed to disclose a delay clock circuit and a differential amplifier with an output driven by an emitter. Those claims of the ’274 patent were not invalidated by the PTAB. Petitioner appealed to the court of appeals for the Federal Circuit.

The Federal Circuit reviewed the PTAB’s decision for substantial evidence. The Federal Circuit agreed with the PTAB’s finding that Tachibana does not anticipate because it fails to disclose the “clock delay circuit.” Similarly, the Federal Circuit agreed that the differential amplifier in Tachibana does not have an output driven by the emitter of bipolar transistor. Based on these conclusions the Federal Circuit affirmed the PTAB’s decision.

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