Method for manufacturing contact hole of NAND flash memory device

Abstract

The invention provides a method for manufacturing a contact hole of an NAND flash memory device. The method comprises the following steps: forming a gate structure and an air gap on a substrate; depositing a first interlayer dielectric layer on the substrate; performing chemical mechanical grinding on the first interlayer dielectric layer, and grinding the upper surface of the first interlayer dielectric layer to be flat; depositing a subsequent interlayer dielectric layer on the substrate; and forming a contact hole on the substrate. According to the manufacturing method of the contact hole of the NAND flash memory device, the first interlayer dielectric layer can be kept horizontal, and then the subsequent interlayer dielectric layer can be kept horizontal, so the etching direction of the contact hole is ensured to form the same contact angle with the interlayer dielectric layers of different layers in a contact hole forming process, and the contact performance of the NAND flash memory device is improved; therefore, the size of a contact hole process window is ensured, and the reliability of the device is improved.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to a method for manufacturing a contact hole of a NAND flash memory device. Background technique [0002] NAND flash memory is a kind of non-volatile memory. Due to its advantages of large capacity, fast erasing and writing speed, and low cost, it is very suitable for storing data and is widely used in consumer, automotive, and industrial electronics. [0003] A NAND memory array usually consists of multiple blocks, and each block includes several word lines, contact holes and metal interconnection lines. With the development of science and technology, the process window of the contact hole process is getting smaller and smaller, refer to figure 1 , figure 1 It is a schematic diagram of the device in the contact hole manufacturing method of the existing NAND flash memory device, and the existing contact hole manufacturing method of the NAND flash memory device gener...

AI Technical Summary

Problems solved by technology

However, during contact hole formation, refer to figure 1 , each layer of dielectric is not horizontal due to the different heights of the front-layer devices, see figure 2 , the etching direction of the contact hole will form different contact angles with the dielectric layers of different heights, which makes even a slight horizontal deviation in the exposure and development of the contact hole cause a significant difference in the amount of etching during etching, making The process window of the contact hole is extremely small, which is a great challenge to reliability

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