Forming method of U-shaped gate

Abstract

The invention provides a method for forming a U-shaped gate. The method comprises: forming an active region and a shallow groove which are isolated in a silicon chip; forming a gate oxide layer and a gate polycrystalline silicon film on the silicon chip in sequence, and depositing a hard mask layer on the gate polycrystalline silicon film; arranging a photoresist, performing first photoetching on the photoresist to form an H-shaped pattern, and transferring the H-shaped pattern to the hard mask by dry etching; filling the H-shaped pattern on the hard mask with a spin filling material; then arranging a photoresist and performing second photoetching to form a photoresist pattern for cutting off the H-shaped pattern on the hard mask to form a U-shaped pattern; transferring the photoresist pattern to the hard mask by dry etching to form the U-shaped pattern; and finally transferring the U-shaped pattern on the hard mask to the polycrystalline silicon by etching to form the U-shaped gate.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, and more specifically, the invention relates to a method for forming a U-shaped gate. Background technique [0002] According to the development of Moore's law, the feature size of VLSI has been developed to the feature size of 28 nanometers and below, in order to integrate more semiconductor devices in a smaller area, increase the capacity of the device, reduce the cost, and form a better performance, lower power semiconductor devices. [0003] However, in the technology process of 28 nanometers and below, take the gate as an example: reducing the line width of the gate can improve integration and reduce the size of the device, but a single line width reduction will encounter a series of problems. The distance between the lines is called the line end distance (Line end to end), and the photolithography process of making small line width gates will produce line end shrinkage (line-end ...

AI Technical Summary

Problems solved by technology

However, the manufacturing process of this scheme is very complicated

[0006] U-shaped Poly is used in forward port SRAM (Due port SRAM). Through U-shaped polysilicon, two NPD devices share the same gate, which increases the read and write capabilities of SRAM. However, U-shaped polysilicon has more complex graphics. , the effect of the arcing of the line end is more obvious, especially in the polysilicon on the active area, the width of the gate is very different due to the arcing, which produces parasitic devices and leads to SRAM failure

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