Inventive Step of Selection Invention – Taiwan IP Court Rejected ROHM AND HAAS’s Patent Application

Date: 4 March 2022

Selection inventions deal with the selection of individual elements, sub-sets, or sub-ranges, which have not been explicitly mentioned, within a larger set or range known in the prior art. Selection inventions are often applied in the technical fields of chemicals and materials. Determination on the inventive step of a selection invention is usually based on whether the selected part can produce an unexpected effect. The Taiwan Intellectual Property and Commercial Court (IP Court) recently rejected ROHM AND HAAS ELECTRONIC MATERIALS KOREA LTD.’s patent application1, clarifying principle of determination on “an unexpected effect” of a selection invention.

Facts

   ROHM AND HAAS ELECTRONIC MATERIALS KOREA LTD. filed a patent application no. 106128653, “MONOMERS, POLYMERS AND PHOTORESIST COMPOSITIONS” (the ‘653 patent) on 23 August, 2017. After reexamination, the Taiwan Intellectual Property Office (IPO) found the ‘653 patent obvious and rejected it on 29 September, 2020. ROHM AND HAAS appealed to the Ministry of Economic Affairs without success, and it therefore appealed to the IP Court, but was still rejected.

Analysis on the ’653 patent and Citation 1

   The ‘653 patent provides a new polymers and photoresists that comprise such polymers. The polymer comprises a structure of the following Formula (IIB):

wherein in Formula (IIB):

X, X′ and X″ are each the same or different linker selected from single bond and –CH-;

A, B and C are each independently hydrogen or fluorine;

R′, R″ and R′″ are each independently hydrogen or a non-hydrogen substituent.

The ‘653 patent provides new photoresist compositions that could provide enhanced imaging capabilities.

   On the other hand, Citation 1(TW 201234109A) discloses a photoresist composition for semiconductor process that comprise one or more materials that have base-reactive groups. The materials may be by polymerization of a monomer that comprises base reactive moieties. The monomer may include those of the following Formula (II):

where Rf is a fluoro or perfluoro alkyl groups (e.g. C1-20 alkyl with 1 to 8 fluoro atoms) with at least the alfa carbon) being fluorinated, and n being an integer equal to or greater than 2.

Additionally, specification of Citation 1 discloses that the monomer may be a base reactive group with several base reactive moieties, more typically 2 or 3 base reactive moieties, namely n may be 2 or 3. Citation 1 also substantially illustrates several monomers with 2 base reactive moieties, such as monomer 24 and monomer 25. Monomer 24 is shown as below:

   Therefore, Citation 1 has disclosed the technical features of the ‘653 patent. The only difference lies in that if the monomer 24 of Citation 1 has one more base reactive moiety with the same structure (namely when n is 3), the monomer will directly correspond to Formula (IIB) of claim 1 of the ‘653 patent.

IP Court’s Opinion

The IP Court found the ‘653 patent obvious based on Citation 1:

(1) Citation 1 has disclosed that the base reactive group of the monomer may typically comprise 2 or 3 base reactive moieties. Furthermore, according to the description in Citation 1, “Preferred base-reactive materials are resin that comprise one or more base-reactive groups…”, a person skilled in the art would understand that he or she may properly enhance the performance of the photoresist by adjusting its composition.

(2) Furthermore, the ‘653 patent fails to prove that said difference has produced an unexpected effect with specific examples or comparative examples in its specification. Hence a person skilled in the art is able to adjust the composition of the photoresist based on said content disclosed by Citation 1, and accomplish claim 1 of the ‘653 patent with limited simple tests, such as optimization tests, at the same time reasonably predict the effect it can achieve.

(3) ROHM AND HAAS asserted that descriptions including paragraph [0047], examples and Table 1 can prove that Formula (IIB) in claim 1 of the ‘653 patent has produced an unexpected effect. However,

i. An advantageous or unexpected effect compared to prior arts should be directly and inevitably produced by all technical features of a claim. The unexpected effect asserted by ROHM AND HAAS is produced by Polymer 7 in the example of the ‘653 patent, which has 3 base reactive moieties. However, the 3 base reactive moieties of Polymer 7 are not bonded with the same carbon. Apparently, Polymer 7 does not correspond to Formula (IIB) of the ‘653 patent.

ii. An “unexpected effect” includes a significant enhancement of an efficacy (i.e., a quantitative change) or a new performance (i.e., a qualitative change). In the ‘653 patent, the adjustment of the number of the base reactive moieties leads to a change of surface tension (contact angles), which is derivable by a person skilled in the art. Therefore, the ‘653 patent produces no qualitative change.

iii. Moreover, ROHM AND HAAS did not provide any data to show a person skilled in the art’s general expect of the above quantitative change or qualitative change, nor any data in comparison with the Table 1 to support its assertion.

Wisdom Wisdom Suggested Strategies

   Determination on the inventive step of a selection invention is ruled in Section 3.5, Chapter 3, Part 2 of the Taiwan Examination Guidelines, and the determination is mainly based on whether “the selected part produces an unexpected effect”. However, to prove the effect, the selected part should have clear relationship with the adopted data. In this case, the applicant tried to prove effect by Polymer 7, but the structure of Polymer 7 is different from which defined in claim 1, leading to a fail to prove the better effect produced by the selected part than Citation 1.

   Furthermore, the IP Court reaffirmed the determination on “quantitative change” and “qualitative change” in this case. If an applicant asserts the selected part has a quantitative change compared to the prior art, data in multiple examples and comparative examples are necessary to prove that the selected part has significant enhancement and, which is more important, that the endpoints of the selected part are critical characters. In this way the examiner can be better convinced of the invention effect.

   On the other hand, regarding a “qualitative change”, Taiwan is quite strict when determining whether it pertains to an unexpected effect. Section 3.4.2.3.1, Chapter 3, Part 2 of the Taiwan Examination Guidelines prescribes that “even if a claimed invention produces a significant enhancement of an effect or a new performance, if such effect is expected for a person skilled in the art at the time of filing, it still does not deem "an unexpected effect." The IP Court in the present case adopts the similar principle. If the effect of a selected part is derivable by a person skilled in the art, it is hard to claim the effect as a qualitative change.

   In summary, the level of inventive step of a selection invention is generally higher than general inventions in Taiwan. Usually sufficient data is necessary to prove the effect, and the data should have clear and direct relationship with the effect. Accordingly, it is important to draft a specification sufficiently, and even if the examples are not enough when responding to an Office Action, it is also advised to supplement experimental data to prove the effect of the selected part.

[1]IP Court 2021 Xingzhuansuzi No. 24 Administrative Judgment).

 

 

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