Low-selectivity etching solution for BPSG and PETEOS films

Abstract

The invention discloses a low-selectivity etching solution for BPSG and PETEOS films. The low-selectivity etching solution comprises the following main components: hydrofluoric acid, an organic solvent, a fluorine-containing compound and amines. Hydrofluoric acid in the etching solution is used for etching BPSG and PETEOS films; the organic solvent is used for reducing the etching rate of the BPSGand PETEOS films by the etching solution, so that the etching reaction is easy to control; the fluorine-containing compound is used as a fluorine ion slow-release agent to provide fluorine ions, stabilize the etching rate of the etching solution and prolong the service life of the etching solution; and the amines are used for reducing the etching rate of the BPSG film, so that the etching rate selection ratio of the BPSG film to the PETEOS film is close to 1. The etching solution provided by the invention can stabilize the etching rate selection ratio of the BPSG film to the PETEOS film at 1.1 + / -0.2.

Description

technical field [0001] The invention relates to the technical field of etching processing of dielectric layers in the semiconductor manufacturing industry, in particular to a low-selectivity etching solution for BPSG and PETEOS films. Background technique [0002] In the semiconductor manufacturing industry, the growth of dielectric layer films is an additive process that provides reliable insulation protection between metal layers and between metal layers and active devices. After the active devices are manufactured on the surface of the wafer, before metal deposition, a dielectric layer will be deposited. Generally, the formation level of the dielectric layer ILD is ① SiON layer deposition (used to prevent the upper layer B and P from penetrating into the device); ② BPSG ( Silicon glass doped with boron and phosphorus (borophosphosilicate glass) layer deposition; ③ PETEOS (plasma enhanced tetraethyl orthosilicate) layer deposition; and finally planarized by ILD Oxide CMP (...

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Problems solved by technology

[0003] When using etchant for etching (see attached figure 1 ), because the etching rate of BPSG is faster than that of PETEOS, the BPSG layer will appear undercutting along with the etching (see attached figure 2 ), affecting the subsequent metal deposition process

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