Semiconductor device and method for manufacturing the same

{
  "publication_number": "US9419018B2",
  "country": "US",
  "kind": "B2",
  "title": "Semiconductor device and method for manufacturing the same",
  "abstract": "A semiconductor device that occupies a small area and has a high degree of integration is provided. The semiconductor device includes a first insulating layer, a conductive layer, and a second insulating layer. The conductive layer is between the first insulating layer and the second insulating layer. The first insulating layer, the conductive layer, and the second insulating layer overlap with each other in a region. A contact plug penetrates the first insulating layer, the conductive layer, and the second insulating layer. In a depth direction from the second insulating layer to the first insulating layer, a diameter of the contact plug changes to a smaller value at an interface between the second insulating layer and the conductive layer.",
  "claims": [
    "1. A method for manufacturing a semiconductor device comprising the steps of: forming a conductive film over a first insulating layer; selectively etching the conductive film to form a conductive layer and a first opening penetrating the conductive layer; forming a second insulating layer over the conductive layer so that the second insulating layer covers the first opening; selectively etching the second insulating layer to form a second opening so as to etch the second insulating layer in the first opening, forming a semiconductor layer including a channel formation region of a transistor; forming a gate insulating layer over the semiconductor layer; and forming a gate electrode over the gate insulating layer, the gate electrode overlapping with the semiconductor layer, wherein the first opening and the second opening overlap with each other, and wherein the conductive layer is one of a source electrode and a drain electrode of the transistor, and the conductive layer is electrically connected to the semiconductor layer.",
    "2. The method according to claim 1, further comprising the step of: selectively etching the first insulating layer using the conductive layer as a mask.",
    "3. The method according to claim 1, further comprising the step of: forming a contact plug in the first opening and the second opening, the contact plug electrically connected to the conductive layer.",
    "4. The method according to claim 1, wherein a third opening is formed in the second insulating layer so that the third opening reaches the gate electrode in the step of selectively etching the second insulating layer.",
    "5. The method according to claim 1, wherein the semiconductor layer includes an oxide semiconductor.",
    "6. A method for manufacturing a semiconductor device comprising the steps of: forming a first transistor; forming a first insulating layer over the first transistor; forming a semiconductor layer of a second transistor over the first insulating layer; forming a conductive film over the first insulating layer; selectively etching the conductive film to form a source electrode of the second transistor, a drain electrode of the second transistor, and a first opening penetrating one of the source electrode and the drain electrode of the second transistor; forming a second insulating layer over the second transistor so that the second insulating layer covers the first opening; and selectively etching the first insulating layer to form a second opening reaching the first transistor, and selectively etching the second insulating layer to form a third opening so as to etch the second insulating layer in the first opening, wherein the first opening, the second opening, and the third opening overlap with one another.",
    "7. The method according to claim 6, further comprising the step of: forming a contact plug in the first opening, the second opening, and the third opening, the contact plug electrically connected to the one of the source electrode and the drain electrode of the second transistor.",
    "8. The method according to claim 6, wherein a fourth opening is formed in the second insulating layer so that the fourth opening reaches a gate electrode of the second transistor in the step of selectively etching the second insulating layer.",
    "9. The method according to claim 6, wherein a semiconductor layer of the first transistor includes silicon, and wherein the semiconductor layer of the second transistor includes an oxide semiconductor.",
    "10. The method according to claim 6, wherein the first transistor includes a gate, a source, and a drain, wherein the one of the source electrode and the drain electrode of the second transistor and one of the source and the drain of the first transistor overlap with each other, and wherein the second opening reaches the one of the source and the drain of the first transistor.",
    "11. The method according to claim 6, wherein the first transistor includes a gate, a source, and a drain, wherein the one of the source electrode and the drain electrode of the second transistor and the gate of the first transistor overlap with each other, and wherein the second opening reaches the gate of the first transistor.",
    "12. The method according to claim 6, wherein a fourth opening is formed in the semiconductor layer of the second transistor, and wherein the first opening and the fourth opening overlap with each other."
  ],
  "description_excerpt": "One embodiment of the present invention relates to a semiconductor device including an oxide semiconductor.\n\nNote that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the present invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, a method for driving any of them, and a method for manufacturing any of them.\n\nIn this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A transistor and a semiconductor circuit are embodiments of semiconductor devices. In some cases, a memory device, a display device, an imaging device, or an electronic device includes a semiconductor device.\n\nA technique by which transistors are formed using semiconductor thin films formed over a substrate having an insulating surface has been attracting attention. The transistor is used in a wide range of electronic devices such as an integrated circuit (IC) or an image display device (also simply referred to as a display device).",
  "cpc": [
    "H10D 84/856",
    "H01L 21/8221",
    "H01L 27/1128",
    "H01L 27/1214",
    "H01L 27/1259",
    "H01L 29/7869",
    "H10B 20/20",
    "H10B 20/50",
    "H10D 30/6713",
    "H10D 30/6734",
    "H10D 30/6743",
    "H10D 30/6755",
    "H10D 30/6757",
    "H10D 84/038",
    "H10D 84/08",
    "H10D 86/021",
    "H10D 86/0221",
    "H10D 86/40",
    "H10D 86/411",
    "H10D 86/423",
    "H10D 86/441",
    "H10D 86/471",
    "H10D 86/60",
    "H10D 87/00",
    "H10D 88/00",
    "H10D 88/01"
  ],
  "ipc": [
    "H01L 27/12",
    "H01L 29/786",
    "H10B 12/00",
    "H10B 41/70",
    "H10P 14/22",
    "H10P 14/40",
    "H01L 21/822"
  ],
  "assignees": [
    "Semiconductor Energy Laboratory Co Ltd"
  ],
  "inventors": [
    "Shinya Sasagawa",
    "Hidekazu Miyairi",
    "Shunpei Yamazaki",
    "Motomu Kurata"
  ],
  "filing_date": "2014-09-17",
  "publication_date": "2016-08-16",
  "grant_date": "2016-08-16",
  "priority_date": "2014-05-30",
  "application_number": "US-201414488936-A",
  "family_id": "54698365",
  "cited_by_count": 257,
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