PTAB

IPR2018-00454

Applied Materials Inc v. Cohen Uri

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multiple Seed Layers for Metallic Interconnects
  • Brief Description: The ’445 patent describes methods for forming metallic interconnect structures on semiconductor substrates using a damascene process. The invention is directed to depositing two or more metallic seed layers with different uniformity profiles to improve the subsequent electroplating of bulk metal, such as copper.

3. Grounds for Unpatentability

Ground 1: Obviousness over Maydan, Rathore, and Nguyen - Claims 1, 2, 4, 6, 7, and 18-20 are obvious over Maydan in view of Rathore, further in view of Nguyen.

  • Prior Art Relied Upon: Maydan (Patent 6,372,633), Rathore (Patent 6,069,068), and Nguyen (Patent 6,122,566).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of references taught every limitation of the challenged claims. Maydan disclosed the foundational method for forming copper interconnects, explicitly teaching the use of electroplating in combination with a Chemical Vapor Deposition (CVD) wetting layer followed by a Physical Vapor Deposition (PVD) seed layer, or a "combination of a CVD/PVD seed layer." While Maydan established the sequence of depositing multiple seed layers, it did not specify layer thicknesses. Rathore addressed known problems in the art with both PVD-only processes (e.g., "hollow shelled line" formation) and CVD processes (e.g., line contamination). To solve these problems, Rathore provided specific, optimized thickness ranges for a dual-layer seed structure: a CVD copper seed layer of about 100-700 Å (meeting the >50 Å limitation of claim 1) and a reduced-thickness PVD copper seed layer of about 600-2000 Å (meeting the >250 Å limitation). Finally, Nguyen supplied the enabling tool for implementing the combined Maydan/Rathore process. Nguyen described a well-known multi-chamber "cluster tool" capable of performing sequential CVD and PVD processes under vacuum, preventing exposure to atmosphere between depositions. Nguyen’s tool included an automatic controller that used "recipes" to manage the deposition sequence, process parameters, and timing, thus disclosing the controller and recipe limitations of the challenged claims.
    • Motivation to Combine: Petitioner asserted a strong motivation to combine the references to solve known, predictable problems. A person of ordinary skill in the art (POSITA), starting with Maydan's general method of using a multi-layer seed structure, would have recognized the known deficiencies associated with unoptimized CVD and PVD layers. The POSITA would have been motivated to consult a reference like Rathore, which was in the same field and addressed the exact same problems of improving electroplated copper interconnects. Applying Rathore's specific thickness ranges to Maydan’s process was a simple optimization to achieve the predictable results of improved electromigration resistance and reduced contamination. To implement this improved Maydan/Rathore process, a POSITA would need a suitable fabrication tool. Nguyen described a standard, commercially available solution: a multi-chamber cluster tool with a programmable controller. A POSITA would have been motivated to use Nguyen's tool to implement the Maydan/Rathore process in a controlled and efficient manner, which was a well-known technique for improving deposition processes.
    • Expectation of Success: Petitioner argued that a POSITA would have had a high expectation of success. The combination involved applying known optimization techniques (Rathore's thicknesses) to a known process (Maydan's layering) using a standard, well-understood piece of equipment (Nguyen's cluster tool). Each step was intended to achieve a predictable, desired outcome, such as better layer quality and process efficiency. The result was merely the sum of the predictable contributions of each prior art element.

4. Key Claim Construction Positions

  • Seed Layer: Petitioner argued that for the purposes of the IPR, the term "seed layer" should be given its plain and ordinary meaning, which a POSITA would have understood as an electrically conductive layer that facilitates the growth of another conductive material. This construction was important for interpreting Maydan's "conformal wetting layer 30" as a first seed layer, a point the Patent Owner had previously conceded during reexamination of a related patent.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 2, 4, 6, 7, and 18-20 of the ’445 patent as unpatentable under 35 U.S.C. §103.