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

Abstract

The present invention provides a stacked layer of a 3D NAND memory device and a manufacturing method thereof. After forming a dielectric layer on a substrate, a groove with a depth not less than the thickness of the stacked layer is formed in the dielectric layer, and then, after a deposition and planarization process, , forming stacked layers within the groove. In this way, after planarization, except for the last layer of the stacked layer, the cross-section of the stacked layer on the side wall of the groove is exposed. Since the first film in the stacked layer and the surface of the dielectric layer are made of different materials, the surface of the dielectric layer Between the last layer of the stacked layer is a narrow strip between the dielectric layer and the sacrificial layer. The narrow strips between the dielectric layer and the sacrificial layer can be obtained by scanning electron microscopy. The stripes can be obtained by measuring the size of the stripes. The thickness of the stacked layer can be accurately obtained, thereby obtaining the thickness uniformity of the stacked layer.

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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