PTAB

IPR2019-00783

Samsung Electronics Co., Ltd. v. ProMOS Technologies, Inc.

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1. Case Identification

2. Patent Overview

  • Title: Control Device for Maintaining a Chemical Mechanical Polishing Machine in a Wet Mode
  • Brief Description: The ’386 patent discloses a control device for a chemical mechanical polishing (CMP) machine. The device is designed to prevent degradation of the CMP process that occurs when residual polishing liquid dries on the polishing pad or carrier head by ensuring the machine is maintained in a wet mode, even when not actively polishing.

3. Grounds for Unpatentability

Ground 1: Obviousness over Miyaji and Shimomura - Claims 1 and 5 are obvious over Miyaji in view of Shimomura.

  • Prior Art Relied Upon: Miyaji (Japanese Patent Publication JP H10-235550) and Shimomura (Japanese Patent Publication JP H10-141403).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Miyaji disclosed all elements of independent claim 1 except for a dedicated sensor that directly detects the opening and closing of the slurry sprinkler. Miyaji taught a CMP system with a control unit that prevents the polishing pad from drying out by sprinkling water if polishing has been stopped for a predetermined time. However, Miyaji determined this "stopped time" indirectly, by sensing when the polishing platen stopped rotating. Petitioner asserted that Shimomura remedied this deficiency by teaching a substrate processing device that uses dedicated sensors directly on the fluid supply valves. These sensors provide a signal to a control unit indicating the precise open/closed state of the valves. Combining these teachings, a person of ordinary skill in the art (POSITA) would arrive at the invention of claim 1: Miyaji’s CMP system and wet-mode maintenance process, improved by incorporating Shimomura’s dedicated valve sensor to more accurately trigger the process. For dependent claim 5, which specifies the liquid is slurry, Petitioner argued Miyaji explicitly disclosed using a polishing agent, or slurry, during its process.
    • Motivation to Combine: A POSITA would combine Miyaji and Shimomura to improve the accuracy and reliability of Miyaji’s system. Miyaji's method of using platen rotation as a proxy for slurry flow is indirect. Shimomura explicitly addressed the need for precise and rapid sensing of fluid supply, a problem analogous to that faced in Miyaji's system. A POSITA would have recognized the benefit of replacing Miyaji’s indirect sensing method with Shimomura’s direct valve sensor to more accurately measure the time the slurry sprinkler is closed. This modification would lead to a more reliable system, better control over fluid usage, and the ability to detect valve malfunctions even during polishing, all of which are predictable improvements.
    • Expectation of Success: Petitioner contended a POSITA would have a reasonable expectation of success in this combination. Both references operate in the predictable field of semiconductor processing equipment. Integrating a known type of sensor (Shimomura) onto a known type of fluid valve within a CMP system (Miyaji) is a straightforward application of existing technologies to achieve a predictable improvement in measurement accuracy.

Ground 2: Obviousness over Miyaji, Shimomura, and Perlov - Claims 2 and 3 are obvious over the combination of Miyaji, Shimomura, and Perlov.

  • Prior Art Relied Upon: Miyaji (Japanese Patent Publication JP H10-235550), Shimomura (Japanese Patent Publication JP H10-141403), and Perlov (European Publication EP0774323A2).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds upon the Miyaji-Shimomura combination from Ground 1 to address dependent claims 2 and 3. Claim 2 requires the liquid sprinkled to be deionized water used for rinsing both the polishing pad and the carrier head. While the base combination taught sprinkling water on the pad, Petitioner argued Perlov supplied the missing elements. Perlov explicitly taught an apparatus and method for CMP that involves rinsing the wafer head (i.e., carrier head) with a cleaning solution, such as deionized water, to remove debris and reduce contamination. Claim 3, which recites that the control unit sprinkles this deionized water, was argued to be a natural and obvious consequence of incorporating Perlov's teachings.
    • Motivation to Combine: A POSITA would be motivated to incorporate Perlov’s teachings to create a more comprehensive cleaning solution. Both Miyaji and Perlov recognized the problem of dried slurry residue adversely affecting the CMP process. Miyaji addressed residue on the polishing pad, while Perlov addressed residue on the carrier head. A POSITA seeking to improve overall system cleanliness and performance would have been motivated to address both known sources of contamination. Therefore, it would have been obvious to modify the Miyaji-Shimomura system to also rinse the carrier head as taught by Perlov. Using deionized water, as taught by Perlov, was a well-known and preferred cleaning agent in the art for such applications, making its use an obvious choice over regular water.
    • Expectation of Success: The combination would have yielded predictable results. Modifying the fluid supply system of Miyaji to add a nozzle directed at the carrier head is a simple, predictable mechanical alteration. The use of deionized water for cleaning in CMP systems was standard, ensuring its implementation would be workable and effective without any unexpected challenges.

4. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 2, 3, and 5 of the ’386 patent as unpatentable.