TSMC’s Semiconductor Process Equipment Patent Found Obvious and Invalidated by IP Court

Date: 11 March 2022

【Volume 73】Parametric or numerical claims are common in inventions in the semiconductor, chemical, materials, mechanical, bio/pharma fields, etc. In order to obtain broader ranges in the claim, values such as composition ratios, size, temperature, frequency, parameters, etc. are rarely recited as single values and are generally presented as a range of values. When the numerical range in a claim partially overlaps with that disclosed by prior art, the patent applicant must demonstrate that the numerical limitations in the claim produces unexpected results over the prior art for it to meet inventive step requirements in accordance with the Taiwan Patent Examination Guidelines.

Recently, the Taiwan Intellectual Property Court (IP Court) held that a numerical patent directed to a semiconductor process equipment owned by Taiwan Semiconductor Manufacturing Corporation (“TSMC”) lacked an inventive step and found it invalid. (TSMC v. Lee Chia-Ying, Taiwan Intellectual Property Court (IP Court)2021 XingZhuanSuZi No. 15 judgment). In the decision, the IP Court provided a detailed analysis of the consideration for the inventive step in a numerical claim, the determination of teaching away, and the recognition of commercial success.

Case Facts

An anonymous petitioner1 filed an invalidation action against TSMC’s patent no. I503920 “Process equipment and O-ring thereof” (the ‘920 patent). The Taiwan Intellectual Property Office (TIPO) decided the patent was invalid, and the Appeals Committee and the IP Court both upheld the decision and dismissed TSMC’s appeals.

Main Technical Features of the ‘920 Patent and Disclosure of Evidence

The main issue in the ‘920 patent was whether the combination of Exhibits 1 to 7 can prove that claims 1 to 11, 13 to 21, 23 to 30 and 32 lack an inventive step. The following only focuses on illustrating the determination of an inventive step of claim 1 and numerical claims 3, 4, 7, 8 and 13.

Claim 1 of ‘920 patent reads: “A semiconductor process equipment for carrying a wafer, comprising: a wafer susceptor body, a fluid supply unit and a carrier element, wherein the carrier element is arranged on the wafer susceptor body and includes an upper surface for carrying the wafer and one side, the fluid supply unit is arranged in the susceptor body to supply a fluid to the wafer on the upper surface of the carrier element, a groove forms the side surface of the carrier element and is located at the point where the susceptor body is connected to the carrier element; and a replaceable O-ring arranged in the groove, and the fluid supplied by the fluid supply unit is sealed by the O-ring, wherein the cross section of the O-ring is rectangular.”

Claim 3 further limits “the ratio of the width of the O-ring to the width of the groove is between 1.00 and 1.20” and claim 4 further limits “the ratio of the center diameter of the O-ring to the center diameter of the groove is between 0.95 and 1.00”. Claim 7 further limits “the ratio of the radial width of the bottom surface of the O-ring to the radial width of the O-ring is between 0.70 and 0.90”. Claim 8 further limits “the ratio of the radial width of the top surface of the O-ring to the radial width of the O-ring is between 0.70 and 0.90”. Claim 13 further limits “the ratio of the radial width to the vertical thickness is between 1:0.8 and 1:4”.

Exhibit 1 is the prior art of the ‘920 patent which only lacks the technical features of the “O-ring” compared to the ‘920 patent.

Exhibit 3 (China Patent publication no. 101286469 “Structure for preventing gap formation and plasma processing apparatus”) has disclosed that replaceable components such as O-rings can be used for the sealing component.

The Opinion of the IP Court and TIPO

1. Numerical claims in the ‘920 patent lack inventive steps

Claims 3, 4, 7, 8 and 13 in the ‘920 patent have further limited the range of ratio values which are not disclosed by the exhibits. However, TIPO and the IP Court deemed that TSMC did not demonstrate that the range of ratio values would produce unexpected results compared to other ratio values, and the range of ratios limited in claims 3, 4, 7 and 8 of the ‘920 patent could be easily accomplished by a person with ordinary knowledge in the art by simple changes in routine work under the actual configuration of grooves and O-rings. Thus, claims 3, 4, 7, 8 and 13 in the ‘920 patent lack an inventive step.

2. The ‘920 patent is not commercially successful

TSMC claimed that the ‘920 patent was commercially successful and shall be non-obvious.

However, the IP court held that the applicant should not only prove that its sales figures of the patented goods were higher than those of similar goods or that it had exclusive market-share or replaced competitors' products, but shall also bear the burden of proof that the commercial success of the patented goods was due to the technical features of the patent. The IP court eventually rejected TSMC’s argument as it failed to prove the causal relationship between the commercial success and the technical features of the ‘920 patent.

3. Exhibit 2 does not “teach away” from the ‘920 patent

TSMC argued that protective element 105 in Exhibit 2 is rigid, which is conceptually and physically the opposite to the flexible “O-ring” used in the ‘920 patent, and “teaches away” from the said patent.

However, the Court deemed that an exhibit only “teaches away” if it expressly states or substantively implies instruction or suggestion on the exclusion of the claimed invention. The use of Teflon resin or ceramic material for the protective element in Exhibit 2 was based on the corrosion resistance of these materials, not on the hardness or elasticity of the Teflon resin or ceramic material. Exhibit 2 did not disclose that alternative materials other than rigid materials may not be used for the protective element, nor did it disclose that the protective element used in Exhibit 2 must exclude materials with elasticity. Thus, there is no technical difficulty or incompatibility in replacing the protective element arranged in the groove of Exhibit 2 with a flexible O-ring disclosed in Exhibits 3 and 5, and Exhibit 2 does not “teach away” from the ‘920 patent.

Wisdom Wisdom Suggested Strategies

Although TSMC introduced numerical features in several claims in the ‘920 patent, it did not provide embodiments or comparative examples in the specification to demonstrate that the numerical features indeed produce unexpected results over the prior art.

In terms of strategy during litigation, TSMC focused only on arguing the motivation to combine the exhibits and failed to provide further convincing experimental data on the numerical claims to prove their unexpected efficacy, which ultimately led to defeat.

In fact, according to the Taiwan Patent Examination Guidelines and past court decisions, the patent applicant is allowed to provide experimental data after the filing date as supplementary information to prove its inventive step, provided that the effect to be proved by the experimental data is recited in the original specification or drawings, or the effect is directly and unambiguously derivable2 . Therefore, if TSMC could supplement experimental data during the litigation, it would be possible to ensure the inventive step of the numerical claims.

Applicants wishing to claim numerical ranges are advised to incorporate sufficient experimental data in the specification to support its efficacy, or at least describe the effect that can be produced from the numerical feature to secure a chance at arguing for the inventive step with supplementary experimental data.

[1]In Taiwan, a petitioner challenging the validity of a patent may choose to remain anonymous.

[2]For more information, please refer to Wisdom News Volume 54, “Patent Post-Filing Data Submission: A Look at Differences between Taiwan and China”.

 

 

 

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