Paragraph 4 of Article 58 of the Patent Act in force stipulates the principle of claim construction: "The scope of the protection conferred by an invention patent is determined by the claim(s), and the description and drawing(s) may be considered as a reference in the interpretation of the claim(s)." In patent disputes, the interpretation of the claims is usually a major focus of both parties because the interpretation of the claims usually determines litigation's outcome. In an administrative judgment made by the IP Court on 27 June 2019 (106-Xing-Zhuan-Su No.58), the patentee and the petitioner for patent invalidation have disputes with respect to the term "pilot run" of the claims. After the IP Court revealed its interpretation of such term, the patentee submitted a post-grant amendment to the claims, and then requested the IP Court to interpret the term "pilot run" again in view of the post-grant amendment.

Claim 2 of the disputed patent pertains to an apparatus for treating a substrate. Claim 2 includes the features "the controlling device treats parts of the substrate processing arrays using normal operation steps, and simultaneously treats other substrate processing arrays using pilot run steps that are used by the processing unit to test, check or verify the qualities of the processing performed on substrates, or is used to check whether the processing unit operates normally." The IP Court interprets the term "pilot run" as "an operation performed in order to check or verify the qualities of the processing performed on substrates, or is used to check whether the processing unit operates normally." Furthermore, the IP Court states that "the same step in the patent is determined to be a normal operation step or a pilot run step depending on its purpose." IP Court's above statements are based on the descriptions of the patent: "the steps used in the substrate processing arrays Lu and Ld belong to the normal operation if their purpose is to process substrates. Additionally, the steps used in the substrate processing arrays Lu and Ld belong to the pilot run if their purpose is to check or verify the qualities of the processing performed on substrates, or is used to check whether the processing unit operates normally."

During litigation, the patentee conducted a post-grant amendment to further limit the above-mentioned feature to 'the controlling device treats parts of the substrate processing arrays using normal operation steps, and simultaneously "modify the steps of processing substrates to" treat other substrate processing arrays using pilot run steps that are used by processing unit to test, check or verify the qualities of the processing performed on substrates, or is used to check whether the processing unit operates normally.' After the above post-grant amendment was accepted by the Intellectual Property Office, the patentee requested the IP Court to interpret the term "pilot run" again based on the amended claim. The patentee asserted that 'a "pilot run" is performed on the substrate processing arrays that are "other than those substrate processing arrays on which the normal operation is performed," and "the steps of processing substrates are modified," to test, check or verify the qualities of the processing performed on substrates, so as to prevent the availability of the apparatus from decreasing.'

Nevertheless, the IP Court did not accept patentee's above assertion. The IP Court states in the judgment that: 'the same term in the claims and the specification should be interpreted consistently, or be interpreted to have the same meaning, and the same term in different claims of a patent should be interpreted to have the same meaning. That is to say, the term "pilot run" of the patent in dispute should be interpreted consistently throughout the specification and the claims. The meaning of such term should not vary in the claims even if these claims include different features. Furthermore, the post-grant amendment providing further limitation to the "controlling device" does not change the interpretation of the term "pilot run" throughout the specification and the claims. Therefore, it is unnecessary to interpret the term "pilot run" again.'

Based on the above, we can see that the content in the specification submitted at the time of filing is important to the interpretation of the claims. The specification should be referred to before a determination can be made regarding whether two terms of the claims are substantially different from each other. In addition, if the patentee intends to strengthen its interpretation of specific terms by making post-grant amendments, the patentee should take the disclosure of the entire specification into consideration and evaluate the attack/defense strategies prudently. In this judgment, the post-grant amendment does not change IP Court's interpretation to the specific term.