Marking pattern in forming staircase structure of three-dimensional memory device
US11594496B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 2021 |
| Grant date | Feb 28, 2023 |
| Priority date | — |
| Expiry date | Nov 23, 2041 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B43/10
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A device area and a marking area neighboring the device area over a dielectric stack are determined. The dielectric stack includes insulating material layers and sacrificial material layers arranged alternatingly over a substrate. The device area and the marking area are patterned using a same etching process to form a marking pattern having a central marking structure in a marking area and a staircase pattern in the device area. The marking pattern and the staircase pattern have a same thickness equal to a thickness of at least one insulating material layer and one sacrificial material layer, and the central marking structure divides the marking area into a first marking sub-area farther from the device area and a second marking sub-area closer to the device area. A first pattern density of the first marking sub-area is greater than or equal to a second pattern density of the second marking sub-area. A photoresist layer is formed to cover the staircase pattern and expose the marking pattern, and the photoresist layer is trimmed to expose a portion of the dielectric stack along a horizontal direction. An etching process is performed to maintain the marking pattern and remove the ex…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.