Three-dimensional memory device with thickened word lines in terrace region and method of making thereof
First Claim
1. A three-dimensional memory device comprising:
- an alternating stack of insulating layers and electrically conductive layers located over a substrate, wherein each of the electrically conductive layers has a respective first thickness in a memory array region and a respective second thickness that is greater than the respective first thickness in a stepped terrace region;
memory stack structures located in the memory array region and vertically extending through the alternating stack, wherein each of the memory stack structures comprises a memory film and a vertical semiconductor channel; and
contact via structures located in the terrace region and contacting a respective one of the electrically conductive layers.
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Abstract
A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate. Memory stack structures are located in a memory array region, each of which includes a memory film and a vertical semiconductor channel. Contact via structures located in the terrace region and contact a respective one of the electrically conductive layers. Each of the electrically conductive layers has a respective first thickness throughout the memory array region and includes a contact portion having a respective second thickness that is greater than the respective first thickness within a terrace region. The greater thickness of the contact portion prevents an etch-through during formation of contact via cavities for forming the contact via structures.
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Citations
21 Claims
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1. A three-dimensional memory device comprising:
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an alternating stack of insulating layers and electrically conductive layers located over a substrate, wherein each of the electrically conductive layers has a respective first thickness in a memory array region and a respective second thickness that is greater than the respective first thickness in a stepped terrace region; memory stack structures located in the memory array region and vertically extending through the alternating stack, wherein each of the memory stack structures comprises a memory film and a vertical semiconductor channel; and contact via structures located in the terrace region and contacting a respective one of the electrically conductive layers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of forming a three-dimensional memory device, comprising:
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forming an alternating stack of insulating layers and sacrificial material layers over a substrate, wherein the alternating stack includes a memory array region in which each of the sacrificial material layers is present and a terrace region in which the sacrificial material layers have a respective lateral extent that decreases as a function of a vertical distance from the substrate; forming self-aligned material portions on physically exposed surfaces of the sacrificial material layers in the terrace region employing a selective deposition process in which a material selectively grows from the physically exposed surfaces of the sacrificial material layers; forming memory stack structures through the alternating stack in the memory array region, wherein each of the memory stack structures comprises a memory film and a vertical semiconductor channel; replacing at least the sacrificial material layers with conductive material layers; and forming contact via structures that contact a respective one of the conductive material layers. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification