Formation method of semiconductor structure

Abstract

The invention provides a method for forming a semiconductor structure, comprising: providing a substrate; forming a cavity layer on the substrate; forming a cavity in the cavity layer; filling the cavity with a sacrificial layer; A via structure having via holes exposing the sacrificial layer; removing the sacrificial layer. In the process of forming the semiconductor structure, before the via structure is formed above the cavity, the cavity is filled with a sacrificial layer, so that in the step of forming the via structure above the cavity, the polymer produced by forming the via structure, etc. The by-products will not fall into the cavity. After the through-hole structure is formed, the sacrificial layer is removed. In the semiconductor structure formed in this way, the inside of the cavity is highly clean; and since the cavity is formed during the formation of the through-hole structure, The interior is filled with sacrificial layers, which reduces the risk of cavity rupture due to stress during the formation of via structures.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a method for forming a semiconductor structure. Background technique [0002] In the wafer manufacturing process, especially the formation of MEMS structures, it is often necessary to form some comb-shaped or tooth-shaped structures above the cavity, and the step of forming the structures includes: forming holes by etching. However, many polymers are often produced during the formation of the structure, and these polymers appear in the pores or cavities and are difficult to be completely removed. [0003] The specific MEMS structure is taken as an example below to illustrate with reference to the accompanying drawings. figure 1 A cross-sectional view of a MEMS structure is shown, a first dielectric layer 02 is formed on a substrate 01, a cavity 03 is formed in the first dielectric layer 02, and a second dielectric layer is formed on the first dielectric layer 02. A plurality of th...

AI Technical Summary

Problems solved by technology

But these two methods have some disadvantages, for example, wet cleaning will leave some chemical reagents in the cavity, which will affect the performance of the device

Although dry removal can avoid the residue of chemical reagents, it cannot remove the etching by-products in the cavity

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