PTAB

IPR2021-00120

Qualcomm Inc v. Monterey Research LLC

Key Events

Petition

petition

Title: Semiconductor Fabrication Process
Brief Description: The ’727 patent discloses structures and processes for forming a dual damascene contact region in an integrated circuit. The invention uses a "multiple etch stop insulation layer" and a "non-lithography spacer formation process" to create "sub spacer regions" that control the contact's dimensions, resulting in a contact with a smaller substrate coupling area than its metal layer coupling area.

Prior Art Relied Upon: Peng (Patent 7,338,903), Brase (Patent 6,576,550).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Peng disclosed a dual damascene process with the same sequence of layers as the ’727 patent’s claimed "multiple etch stop insulation layer," including first and second etch stop layers and first and second sub interlevel dielectric layers. However, Peng described this structure in isolation. Brase was asserted to supply the well-known context of a complete integrated circuit, including a silicon wafer substrate with active devices like transistors containing gate, source, and drain regions, which are necessary to practice the invention.
- Motivation to Combine: A POSITA would combine these references to implement Peng's specific multi-layer damascene structure within a functional integrated circuit. Petitioner contended this was a straightforward application, as Peng explicitly stated its structure was for use in integrated circuit products, and Brase provided the standard, surrounding components needed to create such a product.
- Expectation of Success: The combination was presented as predictable, as Peng's contact formation process operates on layers above the substrate and would not be materially affected by the specific contents of the substrate taught by Brase.

Prior Art Relied Upon: Peng (Patent 7,338,903), Chien (Patent 6,365,504), Brase (Patent 6,576,550).
Core Argument for this Ground:
- Prior Art Mapping: This ground built upon the Peng/Brase combination by adding Chien's teachings. Petitioner asserted Chien disclosed using spacers as an etching mask to define a smaller via opening beneath a larger trench opening in a dual damascene process. Applying Chien’s process to the Peng/Brase structure allegedly met the claim limitations requiring "forming a sub spacer region such that a substrate coupling area... is smaller than a metal layer coupling area," as well as the "non-lithography spacer formation process" recited in claim 9.
- Motivation to Combine: A POSITA would be motivated to incorporate Chien's spacer technique into the Peng/Brase framework to solve known problems in dual damascene fabrication. Chien was argued to explicitly teach that using spacers provides better alignment, enables the creation of smaller vias, and improves overall process control, all of which were known and desirable goals in the art.
- Expectation of Success: Petitioner argued success would be expected because Chien’s spacer process was a known method for forming dual damascene vias and was fully compatible with the general layer structure disclosed by Peng.

Prior Art Relied Upon: Lin (Application # 2004/0124420), Chien (Patent 6,365,504).
Core Argument for this Ground:
- Prior Art Mapping: This ground presented an alternative combination where Lin served as the primary reference. Petitioner argued Lin, like Peng, disclosed a dual damascene structure with the claimed sequence of four alternating etch stop and dielectric layers. Lin was asserted to also explicitly disclose forming the trench opening by etching through both the upper dielectric layer and the second etch stop layer. Chien was again relied upon for its disclosure of using spacers as an etch mask to form the via.
- Motivation to Combine: The motivation to combine Lin and Chien was identical to that for combining Peng and Chien in Ground 2. A POSITA would have recognized the advantages of Chien's spacer method for improving alignment and process control and would have applied it to the dual damascene process taught by Lin.
Additional Grounds: Petitioner asserted additional obviousness challenges (Grounds 4-6) against claim 6 based on modifying the combinations in Grounds 1, 2, and 3 with Chen (Patent 6,570,257). Chen was argued to teach depositing an anti-reflective coating layer to improve dimensional control during etching.

"a sub spacer region such that a substrate coupling area of said contact region is smaller than a metal layer coupling area of said contact region"
- Petitioner proposed that this phrase requires the "sub spacer region" to control, at least in part, the size of the substrate coupling area, for example by serving as an etch mask. Petitioner argued this construction is consistent with the patent's disclosure that the substrate coupling area width "can be controlled by spacer width." This construction was contrasted with the Patent Owner's apparent litigation position, which Petitioner characterized as merely requiring the presence of the spacer and the resulting dimensional relationship, without a causal link.

Petitioner argued that the grounds presented were not cumulative of the prosecution history. It was noted that the primary references of Peng, Lin, Brase, and Chen were never before the Examiner. While Chien was considered during prosecution, Petitioner asserted it was applied here in a new combination not asserted by the Examiner, relying on Chien's undisputed teaching of using spacers as an etch mask—a point the applicants did not contest during prosecution.

Petitioner requests institution of an inter partes review and cancellation of claims 1-4, 6, 7, and 9-13 of the ’727 patent as unpatentable under 35 U.S.C. §103.