High-selectivity etching solution for aluminum nitride and silicon

Abstract

The invention discloses a high-selectivity etching solution for aluminum nitride and silicon. The etching solution comprises the following main components in percentage by mass: 5-40% of alkali, 0.2-0.5% of fluoride, 0.1-0.5% of organochlorosilane, 1-5% of silicate and the balance of water. The etching solution can be used for quickly cleaning the aluminum nitride layer, no crystal lattice remains, and the selection ratio of the etching solution to the Si substrate can reach more than 1000.

Description

technical field [0001] The invention belongs to the field of electronic chemicals. Background technique [0002] Due to the wide bandgap, strong polarization and 6.2eV forbidden band width of AlN, the aluminum nitride thin film materials prepared by it have many excellent physical and chemical properties, such as high breakdown field strength, high thermal conductivity, high resistivity, high Chemical and thermal stability and good optical and mechanical properties. High-quality AlN film also has the characteristics of extremely high ultrasonic transmission speed, small acoustic loss, considerable piezoelectric coupling constant, and similar thermal expansion coefficient to Si and GaAs. The unique properties make it widely used in machinery, microelectronics, Optical and electronic components, surface acoustic wave device manufacturing and high-frequency broadband communication have broad application prospects. [0003] Because aluminum nitride thin film materials have exc...

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Problems solved by technology

However, the following problems exist in the current etching of aluminum nitride: the use of acidic etching solution to etch aluminum nitride, the etching process temperature is high, the etching rate is low, and the process time is long; the above problems can be avoided by using alkaline etching solution, but each of the alkaline etching solution Anisotropic etching can cause silicon nitride etch crystal residue and damage to the underlying silicon

[0004] There are more or less disadvantages in the etching solution disclosed in the existing literature: CN107829114A selects the molten NaOH-KOH eutectic mixture as the etching solution to corrode the aluminum nitride crystal Clean the surface with organic solvent before and after corrosion, and wash with concentrated acid to remove molten alkali after corrosion

But its etching rate for AlN is only about 50A / min

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