Compensation device and method for overlay deviation in three-dimensional memory exposure system

Abstract

The invention provides a compensation method for overlay deviation in a three-dimensional memory exposure system. The method comprises the steps that overlay deviation values of different regions in anaked crystal of an exposed wafer are acquired, and a region overlay deviation model is established according to all the regions and the corresponding overlay deviation values; compensation is performed on a photomask pattern according to the region overlay deviation model; and a naked crystal of a to-be-exposed wafer is exposed according to the photomask pattern subject to compensation. Comparedwith the prior art, through the overlay compensation method and a three-dimensional memory, the regular region overlay deviation model of the overlay deviation caused by local stress is established according to a large amount of scanning electron microscope section data, compensation is performed on the photomask pattern on the current layer according to the model, therefore, the overlay deviation within the overall range of naked crystals is lowered, and the problem of yield loss resulting from the overlay deviation is solved.

Description

technical field [0001] The invention relates to the field of three-dimensional memory, in particular to a compensating device and method for overlay deviation in a three-dimensional memory exposure system. Background technique [0002] 3D NAND memory is a new type of flash memory that addresses the limitations of 2D or planar NAND flash memory by stacking memory cells. In the manufacturing process of 3D NAND memory, many steps of film deposition and high-temperature thermodynamic processes such as rapid annealing are required. These processes will cause severe stress changes and deformations in the whole and local areas of the wafer. These local stress changes will aggravate the overlay (OVL) deviation in the subsequent photolithography process. [0003] In the lithography process, the overlay deviation is reduced through the cooperation of three parts: the alignment system of the lithography machine, the overlay deviation measurement equipment and the alignment correction ...

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Problems solved by technology

[0004] 1. Since the measurement is the offset error between overlay marks (OVL Mark), the measurement result does not reflect the actual overlay deviation between patterns;

[0005] 2. Since the measurement is the offset error between the overlay marks, the exposure machine can only make compensation according to the error information of the overlay marks, and it compensates the error within a field (filed) range on the die , instead of compensating for the overlay deviation within the entire die range, it cannot fundamentally solve the overlay deviation problem;

[0006] 3. It cannot fundamentally solve the problem of yield loss caused by overlay deviation

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