Air gap forming method

Abstract

The invention discloses an air gap forming method. According to the method, the critical size of a cannelure is required to be larger than the critical size required by technology requirements when technological design of the cannelure is carried out, a mould-keeping covering layer is deposited in the cannelure in a large critical size, a mould-keeping covering layer on the bottom of the cannelure and a mould-keeping covering layer on the upper surface of a semiconductor substrate are removed, a mould-keeping covering sacrificial layer is reserved, the subsequent filling process is continued, and finally the mould-keeping covering sacrificial layer is removed and a blocking layer is deposited on the top of the cannelure to obtain an air gap structure. According to the air gap forming method, the number of processing steps is small, material consumption is low, critical sizes of a through hole and the cannelure are increased during photoetching and etching while RC delay is improved, technological difficulty is reduced, production efficiency is improved, and production cost is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming an air gap. Background technique [0002] With the continuous development of integrated circuits in accordance with Moore's Law, the integration level is getting higher and higher, and the feature size of chips is getting smaller and smaller. As an important process step in the field of semiconductor manufacturing technology, metal interconnection has an increasing impact on device yield. more important. For example, in a 45nm chip, the number of metal interconnection layers is as high as 10, so the capacitance between metal wires, the interlayer capacitance and the resistance of metal wires play an increasingly important role in the factors affecting the yield of devices. Increased capacitance between metal wires, interlayer capacitance, and resistance of metal wires will lead to increased wiring RC (resistor-capacitance) delay time, cro...

AI Technical Summary

Problems solved by technology

[0009] In view of the above-mentioned problems, the present invention provides a method for forming an air gap to overcome the cumbersome process steps in the prior art, consume more raw materials, and consume a lot of process time, thereby reducing production efficiency and increasing production costs. The problem of increasing the manufacturing cost of the device can improve the production efficiency and reduce the production cost while improving the RC delay.

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