{
  "patent_number": "US 9947413",
  "country": "US",
  "title": "How to Program 3D Layered Memory Chips More Precisely",
  "original_title": "Method of initializing and programming 3D non-volatile memory device",
  "summary": "This patent describes a method for precisely programming the control transistors and memory cells in advanced 3D non-volatile memory chips, ensuring reliable data storage in stacked layers.",
  "what_it_does": "This patent details a method for setting up and programming 3D non-volatile memory devices, which are like tiny, layered data storage cities. First, it applies a specific voltage (a \"first program voltage\") to a \"selected string selection line\" (a control wire) in a chosen memory layer (Claim 1). Then, it checks if the \"string selection transistors\" (SSTs, which are like gates for memory strings) connected to that wire have reached a target \"threshold voltage\" (the voltage needed to turn them on). This check identifies which SSTs are already \"programmed\" and which are \"unprogrammed\" (Claim 1). Next, it programs the actual \"memory cell transistors\" (MCTs) within the memory strings that are coupled with the *programmed* SSTs. These MCTs are set to a specific threshold voltage so they can function as \"screening transistors\" (Claim 1). Finally, it uses these newly programmed MCTs to block programming to the channel lines of the *programmed* SSTs, while a \"third program voltage\" is applied to the selected string selection line to *selectively program* only the *unprogrammed* SSTs (Claim 1). This ensures precise control over which parts of the memory are programmed.",
  "what_it_does_not_cover": [
    "Does not cover programming methods for traditional 2D (planar) non-volatile memory structures.",
    "Does not cover programming string selection transistors without an intermediate verification step to distinguish programmed from unprogrammed ones.",
    "Does not cover programming memory cell transistors without using them as screening transistors for subsequent string selection transistor programming.",
    "Does not cover memory architectures that do not include distinct string selection lines, wordlines, and channel lines in a 3D arrangement.",
    "Does not cover programming techniques that do not involve applying a first, second, and third program voltage in the specified sequence."
  ],
  "filed": "2016-11-03",
  "granted": "2018-04-17",
  "expires": "2036-11-03",
  "status": "active",
  "holder": "Seoul National University R&DB Foundation",
  "holder_url": "https://patentbrief.org/company/seoul-national-university-rdb-foundation",
  "inventors": [
    {
      "name": "Dae Woong KWON",
      "url": "https://patentbrief.org/inventor/dae-woong-kwon"
    },
    {
      "name": "Byung Gook Park",
      "url": "https://patentbrief.org/inventor/byung-gook-park"
    },
    {
      "name": "Sang Ho Lee",
      "url": "https://patentbrief.org/inventor/sang-ho-lee"
    },
    {
      "name": "Do Bin KIM",
      "url": "https://patentbrief.org/inventor/do-bin-kim"
    }
  ],
  "times_cited": 0,
  "tags": [
    "consumer_electronics",
    "semiconductors",
    "telecommunications",
    "software"
  ],
  "abstract": "A method of initializing and programming a 3D non-volatile memory device includes applying a first program voltage to a selected string selection line coupled to a selected memory layer among the plurality of memory layers; verifying whether threshold voltages of a plurality of string selection transistors reach a target value to determine the plurality of string selection transistors as programmed string selection transistors or unprogrammed string selection transistors; programming memory cell transistors of one or more of memory strings coupled with the programmed string selection transistors to have a predetermined threshold voltage, by applying a second program voltage to a selected wordline among the plurality of wordlines; and program-inhibiting channel lines of the programmed string selection transistors using the programmed memory cell transistors as screening transistors and applying a third program voltage to the selected string selection line to selectively program the unprogrammed string selection transistors.",
  "url": "https://patentbrief.org/patent/us/9947413/method-of-initializing-and-programming-3d-non-volatile-memory-device",
  "markdown_url": "https://patentbrief.org/patent/us/9947413/method-of-initializing-and-programming-3d-non-volatile-memory-device/md",
  "google_patents_url": "https://patents.google.com/patent/US9947413",
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}