A high selectivity tungsten etching solution

Abstract

The invention relates to a tungsten etching solution with high selectivity. The etching solution is composed of hydrogen peroxide, inorganic acid, organic base, diethylene glycol monobutyl ether, metal ion masking agent and deionized water. The inorganic acid is at least one of sulfuric acid and phosphoric acid, and the organic base is at least one of octylamine and hexamethylenetetramine. Among them, hydrogen peroxide is the oxidizing agent to oxidize tungsten metal, and then the inorganic acid provides H + ions, metal oxides are then replaced by H 3 o + Dissolved into water-soluble metal ions. Diethylene glycol monobutyl ether is a solubilizer, which increases the solubility of the etching solution and also inhibits the decomposition of hydrogen peroxide. The metal ion masking agent has a complex reaction with metal ions, which prevents the acceleration of the metal etching reaction, keeps the etching rate stable, improves the etching selectivity, prevents the decomposition of hydrogen peroxide, and prolongs the life of the etching solution. The tungsten etchant with high selectivity ratio in the present invention can have a higher selectivity ratio than copper, aluminum, molybdenum and silicon dioxide, and can also maintain a stable etching rate and service life.

Description

technical field [0001] The invention belongs to the technical field of metal wet etching and filter intersection, and in particular relates to a tungsten etching solution with a high selectivity ratio. Background technique [0002] In the era when 5G network construction is fully moving into the fast lane, filters, as key components of radio frequency modules, are widely used in the communication field to separate useful signals from noise, improve signal anti-interference and signal-to-noise ratio, and obtain the required signal of. In the manufacture of filters, the film layer structure of metals (such as tungsten, copper, molybdenum, aluminum, etc.) and their alloys are usually involved to form conductive materials such as specific contacts or interconnection lines. Therefore, in the case of the coexistence of multiple metal structures, when etching a specific metal layer, other metal structures must be protected in advance with a PR mask, which adds complicated processe...

AI Technical Summary

Problems solved by technology

Therefore, in the case of the coexistence of multiple metal structures, when etching a specific metal layer, other metal structures must be protected in advance with a PR mask, which adds complicated processes and costs to the manufacturing. At the same time, the multi-layer metal stack In the structure, prone to undercut phenomenon

[0003] Therefore, the development of a metal etching solution with a high selectivity ratio has a very high etching rate for the metal layer to be etched, and the etching rate of other metal structure layers and silicon dioxide base layers is low or even not etched, so as to solve the above technical difficulties

Images