Semiconductor-Process Patents Not Infringed
March 16, 2005
Last Month at the Federal Circuit - April 2005
Judges: Bryson (author), Newman, and Friedman
Holding that a claim limitation directed to the evacuation of gases from a reaction space of a semiconductor-manufacturing system does not cover blowing out the gases using an inert gas, the Federal Circuit in ASM America, Inc. v. Genus, Inc., No. 04-1211 (Fed. Cir. Mar. 16, 2005), affirmed the SJ of noninfringement granted in favor of Genus, Inc. (“Genus”).
The two patents-in-suit—U.S. Patent Nos. 6,015,590 (“the ‘590 patent”) and 5,916,365 (“the ‘365 patent”)—are both directed to a particular form of Atomic Layer Deposition (“ALD”). The claims recite a limitation where a previously used reactant gas is “evacuated” from a reaction space. The district court construed this limitation to cover only a vacuum-purge method and not a gas-insertion method of evacuation, and granted SJ of noninfringement with respect to both patents.
On appeal, the Federal Circuit agreed with the district court’s construction. The Court pointed to ASM America, Inc.’s (“ASM”) own expert, who stated that the evacuation limitation should be read to require the use of a vacuum pump. As further support, the Court noted that the specification, the claim, and the prosecution history all treat the evacuation limitation and the use of inert gas to blow out the reactant gas as two separate steps. For example, ASM argued during prosecution that the use of inert gas to push out the reactant gas allows the use of a less powerful and cheaper vacuum pump than the one disclosed by a prior art reference.
The ‘365 patent also includes a claim that recites evacuating the chamber of gases, and the Court held this limitation to be analogous to the evacuation limitation of the ‘590 patent. Accordingly, the Court also limited the evacuation limitation of the ‘365 patent claim to mean only a vacuum-purge evacuation. ASM argued that the specification supports a broader interpretation because it discusses a previously disclosed process of evacuating excess gas by flowing a purge gas through the reactor between each exposure cycle. The Court was not persuaded, however, because the limitation on its face means only that the gas is removed; the limitation does not recite an insertion of gas.
ASM argued that in the ‘365 patent, “evacuating the chamber of gases” should be read to mean evacuating the chamber of reactant gases and not all of the gases. The Court rejected this argument, however, because the term appears three times in the claim and there is no introduction of a reactant gas prior to the first recitation of the term. Thus, an interpretation of the term to mean the evacuation of only the reactant gases would lead to a nonsensical result. Additionally, the specification repeatedly refers to the evacuation of the chamber of gases using a vacuum pump and distinguishes such an evacuation from the process of purging with an inert gas. The Court also cited statements made by ASM’s Chief Technology Officer, who indicated that the ‘365 patent is limited to evacuation by vacuum pumping, and language from the inventor’s notebook emphasizing the essential requirement for a vacuum chamber, with each step of the process involving an evacuation.