PTAB

IPR2023-00904

Micron Technology Inc v. Sonrai Memory Ltd

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1. Case Identification

2. Patent Overview

  • Title: PORTABLE RAM DRIVE
  • Brief Description: The ’527 patent discloses a portable memory apparatus that uses both volatile (e.g., RAM) and non-volatile (e.g., flash) memory. Upon connection to a computer, data is copied from the non-volatile to the volatile memory for faster access; an internal power source enables the reverse data transfer upon disconnection to prevent data loss.

3. Grounds for Unpatentability

Ground 1: Claims 1, 6, 9, 11-12, 14-15 are obvious over Tsunoda.

  • Prior Art Relied Upon: Tsunoda (Application # 2003/0028733).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Tsunoda disclosed all limitations of independent claims 1 and 15. Tsunoda’s memory apparatus, described as a MultiMediaCard (MMC), is a portable device comprising a housing, a memory control unit, volatile memory (SDRAM), and non-volatile memory (flash). Petitioner asserted that Tsunoda’s MMC interface functions as a connector to a host computer system. Upon connection and power-up, the controller copies data from flash to SDRAM for high-speed access by the host, satisfying the core functional limitations of the challenged claims.
    • Key Aspects: Petitioner contended that limitations in various dependent claims, such as the use of specific DRAM types (claim 9), an impact-resistant shell made of ABS plastic (claims 11 and 14), and having no moving parts (claim 12), were either explicitly taught or made obvious by Tsunoda's disclosure of a solid-state MMC form factor.

Ground 2: Claims 1, 6-7, 9-12, 14-15, and 18 are obvious over Tsunoda in view of Sukegawa.

  • Prior Art Relied Upon: Tsunoda (Application # 2003/0028733) and Sukegawa (Patent 7,069,370).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground asserted that while Tsunoda taught the core memory architecture, Sukegawa taught implementing such a device in a more conventional and convenient USB flash drive form factor. Sukegawa disclosed a small, portable USB memory apparatus with a housing and an integrated USB connector. Petitioner contended that combining Tsunoda’s internal architecture within Sukegawa’s USB form factor would render claim 1 obvious. Further, Sukegawa’s disclosure of indicator lights for data access rendered claims 7 and 18 obvious.
    • Motivation to Combine: A POSITA would combine Tsunoda with Sukegawa to gain the advantages of a universal serial bus (USB) interface, such as plug-and-play capability and high-speed data transfer without needing special adapters, which were known benefits over MMC interfaces. Tsunoda itself contemplated using interfaces other than MMC, directing a POSITA to known alternatives like USB.
    • Expectation of Success: Petitioner argued success was predictable, as implementing known memory architectures in standard USB housings was a common and well-understood practice in the art at the time.

Ground 3: Claims 2-5 and 16-17 are obvious over Tsunoda and Tomio (and optionally Sukegawa).

  • Prior Art Relied Upon: Tsunoda (Application # 2003/0028733), Tomio (Japanese Application # 2001-005723), and optionally Sukegawa (Patent 7,069,370).

  • Core Argument for this Ground:

    • Prior Art Mapping: These grounds addressed claims requiring an internal, rechargeable power source (claims 2, 4, 5, 16, 17). Petitioner argued that while Tsunoda disclosed data transfer upon disconnection, it did not account for abrupt power loss. Tomio remedied this deficiency by teaching a semiconductor memory apparatus with a rechargeable battery that provides backup power to ensure data can be copied from volatile (DRAM) to non-volatile (flash) memory if external power is suddenly cut.
    • Motivation to Combine: A POSITA would combine Tomio’s backup power solution with Tsunoda's apparatus to prevent data loss—a known problem in such devices. This combination would improve device reliability by ensuring data is safely written back to non-volatile memory even if the device is unplugged unexpectedly.
    • Expectation of Success: The combination was argued to be a predictable integration of a known solution (a backup battery) to address a known problem (data loss on power interruption) in the relevant field of portable memory.

  • Additional Grounds: Petitioner asserted numerous other obviousness challenges, including grounds combining the above references with Shigeo (Japanese Application # 2000-112836) to address data management when battery power is low. Additional grounds based on Tomio alone or Tomio with Sukegawa were also presented.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial would be improper under both the General Plastic and Fintiv frameworks.
  • Under General Plastic, Petitioner emphasized that it is a different entity from petitioners in prior, terminated IPRs against the ’527 patent, that this petition relies on new prior art combinations not previously considered by the Board, and that it was filed promptly after discovering the references.
  • Regarding Fintiv, Petitioner asserted that it filed a stipulation agreeing not to pursue in parallel district court litigation the same grounds raised in the petition, or any grounds that could have reasonably been raised. Petitioner argued that under binding agency guidance, this stipulation weighs decisively against a Fintiv-based denial.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-7, 9-18, and 20 of the ’527 patent as unpatentable.