A stacked layer of a 3D NAND storage device and its manufacturing method

Abstract

The invention provides a 3D NAND storage device stacking layer and a manufacture method thereof. After a medium layer is formed on a substrate, a groove with the depth not smaller than the thickness of the stacking layer is formed in the medium layer; after deposition and planarization processes, the stacking layer is formed in the groove. Therefore, after planarization, except the last layer of the stacking layer, the fracture surface of the stacking layer on the side wall of the groove is exposed; a first layer film in the stacking layer and the surface of the medium layer are not made fromsame materials, a narrow strip for separating the medium layer from a sacrificial layer is arranged between the medium layer and the last layer of the stacking layer, and bright-dark stripes of the narrow strip for separating the medium layer from the sacrificial layer can be acquired by a scanning electron microscope; the thickness of the stacking layer can be acquired through measurement of thesize of the stripes, so that the thickness of the stacking layer is acquired accurately, and thickness uniformity of the stacking layer is further acquired.

Description

technical field [0001] The invention relates to the field of 3D NAND devices and manufacturing thereof, in particular to a stacked layer of a 3D NAND storage device and a manufacturing method thereof. Background technique [0002] NAND devices are better storage devices than hard disk drives, and are widely used in electronic products as people pursue non-volatile storage products with low power consumption, light weight and good performance. At present, the planar structure NAND flash memory is close to the limit of practical expansion. In order to further increase the storage capacity and reduce the storage cost per bit, a 3D structure NAND memory device is proposed. [0003] In the 3D NAND memory structure, a stacked 3D NAND memory structure is realized by vertically stacking multiple layers of data storage units. When forming a 3D NAND memory, first, a stacked layer in which sacrificial layers and insulating layers are alternately stacked is formed on a substrate, where...

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Problems solved by technology

At present, the thickness of the film is mainly obtained based on optical ellipsometry, which indirectly obtains the thickness information of the film based on the change of the light ellipsometry after the light passes through the film. However, due to the stacking of insulating layers and sacrificial layers in the stack There are too many layers, and there is a strong optical correlation between the films located in different layers. The measurement method based on optical ellipsometry cannot directly obtain the thickness of the stacked layer, so the thickness uniformity of the stacked layer cannot be accurately obtained

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