Applied Materials Inc v. Uri Cohen

1. Case Identification

• Case #: IPR2018-00730
• Patent #: 6,518,668
• Filed: March 6, 2018
• Petitioner(s): Applied Materials, Inc.
• Patent Owner(s): Dr. Uri Cohen
• Challenged Claims: 6, 9-10, 17-20, 22-24, 27, 33, 35, 38-39, 48, and 49-58

2. Patent Overview

• Title: Multiple Seed Layers For Metallic Interconnects
• Brief Description: The ’668 patent discloses a semiconductor fabrication method using a multiple seed layer structure to improve the filling of high-aspect-ratio openings (e.g., vias) with electroplated metal. The structure involves depositing a "substantially conformal seed layer" and a "substantially non-conformal seed layer" to ensure continuous coverage and facilitate void-free filling.

3. Grounds for Unpatentability

Ground 1: Claims 6, 9-10, 17-20, 22-24, 27, 33, 35, 38-39, 48, and 49-58 are obvious over Maydan in view of Rathore and Brown.

• Prior Art Relied Upon: Maydan (Patent 6,732,633), Rathore (Patent 6,069,068), and Brown (Patent 6,187,670).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the combination of references teaches all limitations of the challenged claims. Maydan was asserted to disclose the foundational method: forming a metallic interconnect by depositing a conformal copper wetting layer (via Chemical Vapor Deposition, or CVD), followed by a combination of CVD or Physical Vapor Deposition (PVD) seed layers, and finally filling the via with an electroplated layer. This establishes the claimed multi-layer seed structure. However, Maydan did not explicitly describe the specific conformality or relative thicknesses recited in the challenged claims.
  • To address the "substantially conformal" and "substantially non-conformal" limitations, Petitioner argued that a Person of Ordinary Skill in the Art (POSITA) would have known that CVD typically produces highly conformal layers (approaching 100% step coverage), while PVD produces non-conformal layers. Brown was cited to explicitly teach that traditional PVD sputtering results in a non-conformal layer with sidewall coverage of approximately 5% or less relative to the field thickness, which falls squarely within the ’668 patent’s definition of "substantially non-conformal" (less than 25%).
  • To supply the missing teaching of relative layer thickness, Petitioner relied on Rathore. Rathore was argued to teach configuring a seed layer stack to balance performance and process issues. It discloses that a thinner CVD layer minimizes contamination risks, while a relatively thicker (but still reduced-thickness) PVD layer can avoid voids and improve electromigration resistance. Petitioner contended it would have been obvious to apply Rathore's thickness optimization teachings to Maydan's process. Therefore, a POSITA would combine the references to create a structure with a thin, conformal CVD layer and a thicker, non-conformal PVD layer, as claimed.
  • Motivation to Combine: Petitioner asserted a strong motivation to combine, as all three references address the same problem in the same field: improving the reliability of electroplated copper interconnects in semiconductor manufacturing. A POSITA seeking to optimize the known multi-layer process in Maydan would have naturally looked to contemporaneous art like Rathore and Brown for solutions to known issues like layer thickness, conformality, voiding, and contamination. The combination was presented as the application of known techniques (CVD, PVD) and known design optimizations (relative thicknesses) to a known process to achieve predictable results.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success. Combining the teachings would involve using well-understood deposition techniques (CVD for conformal coverage, PVD for bulk deposition) with predictable outcomes. Applying Rathore's guidance on layer thicknesses to Maydan's framework would predictably result in an interconnect with improved fill characteristics and electromigration resistance, as all references suggest.

4. Key Claim Construction Positions

• Petitioner argued for express construction of key terms based on the patentee acting as his own lexicographer, asserting these constructions are dispositive.
• "Substantially Conformal Seed Layer": Proposed construction is "a layer whose thickness on the sidewalls of an opening (at about mid-depth) is about 25-100% of its thickness on the field." This is based on an explicit definition in the ’668 patent specification.
• "Substantially Non-conformal Seed Layer": Proposed construction is "a layer whose thickness on the sidewalls of an opening (at about mid-depth) is less than about 25% of its thickness on the field." This is also based on an explicit definition in the specification.
• Petitioner contended these explicit definitions overcome any presumption of claim differentiation between independent claim 6 (which uses the terms without defining them) and dependent claim 9 (which recites the definitions). This construction was central to mapping the percentage-based disclosures of the prior art (e.g., Brown) to the claim limitations.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) or §325(d) would be inappropriate.
• It was acknowledged that related IPR petitions (IPR2018-00448 and IPR2018-00449) against the same patent had been filed, but Petitioner asserted that this petition challenges a different set of claims on different grounds and references.
• Petitioner argued that the filing was not abusive under the General Plastics factors and that instituting review served the public interest in challenging potentially invalid patents.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 6, 9-10, 17-20, 22-24, 27, 33, 35, 38-39, 48, and 49-58 of the ’668 patent as unpatentable.