CN-119463880-B - Quartz crystal etching solution

CN119463880BCN 119463880 BCN119463880 BCN 119463880BCN-119463880-B

Abstract

The invention relates to an etching solution for quartz crystals. The etching solution consists of the following components in percentage by mass, 20% of hydrofluoric acid, 15% of nitric acid, 0.15-0.7% of additive and the balance of ultrapure water. The four-component additive comprises sodium butylnaphthalene sulfonate, PE6400, 1-butyl-3-methylimidazole tetrafluoroborate and 4-mercaptobutyric acid. Wherein, the sodium butylnaphthalene sulfonate prevents particles generated in the etching process from gathering and depositing, and maintains the clarity and uniformity of the etching solution. PE6400 has both hydrophilicity and hydrophobicity, and plays roles of dissolution assistance, dispersion and defoaming. The two can obviously reduce the residual protrusion after quartz crystal etching, reduce the roughness and make the surface smoother. The cooperation of the 1-butyl-3-methylimidazole tetrafluoroborate and the 4-mercaptobutyric acid can control quartz undercut to generate a symmetrical V-shaped structure.

Inventors

YANG CUICUI
PU SHUAI
ZHANG TING
HE ZHAOBO
LI JINHANG
WU HAORAN
YE RUI
OUYANG KEYIN
XU ZHEN
Dong Panfei

Assignees

湖北兴福电子材料股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241122

Claims (3)

1. The quartz crystal etching liquid is characterized by comprising, by mass, 15-25% of hydrofluoric acid, 10-20% of nitric acid, 0.01-0.083% of sodium butylnaphthalene sulfonate, 0.075-0.45% of PE6400,0.017-0.1% of 1-butyl-3-methylimidazole tetrafluoroborate, 0.033-0.1% of 4-mercaptobutyric acid and the balance of ultrapure water.
2. The quartz crystal etching solution according to claim 1, wherein the etching solution comprises the following components in mass fraction: 15-25% of hydrofluoric acid, 12-16% of nitric acid, 0.03-0.06% of sodium butylnaphthalene sulfonate, 0.09-0.3% of PE6400, 0.02-0.06% of 1-butyl-3-methylimidazole tetrafluoroborate, 0.045-0.85% of 4-mercaptobutyric acid and the balance of ultrapure water.
3. Use of the quartz crystal etching solution according to any of claims 1-2 for V-etching of quartz crystals.

Description

Quartz crystal etching solution Technical Field The invention belongs to the technical field of semiconductor material processing, and particularly relates to a quartz crystal etching solution. Background During resonator fabrication, the quartz crystal needs to be precisely etched to the tuning fork structure. The smooth and regular side-etched surface can reduce the resonance resistance and aging rate of the crystal resonator, and can ensure the consistency of frequency, thereby improving the performance stability and reliability of the resonator. However, the conventional etching solution is often etched sideways to form an irregular shape, left and right sides are asymmetric, and a protrusion remains. Therefore, it is important to develop an etching solution having a symmetrical regular shape for undercut, which can reduce etching residues and lower roughness of the etched surface. Disclosure of Invention In order to solve the problems, the invention aims to provide a quartz crystal etching solution, which aims to form symmetrical regular-shape undercut, reduce residues on the etched quartz crystal, reduce roughness and enable the surface to be smoother. The technical scheme of the invention is as follows: a quartz crystal etching solution, which comprises the following components in percentage by mass: 15-25% of hydrofluoric acid, 10-20% of nitric acid, 0.15-0.7% of additive, and the balance of ultrapure water. Preferably, the additive is sodium butylnaphthalene sulfonate, PE6400 (Pasteur Pluronic PE6400 is an ethylene oxide-propylene oxide copolymer), 1-butyl-3-methylimidazolium tetrafluoroborate, 4-mercaptobutyric acid, or a combination thereof. Preferably, the etching solution comprises, by mass, 15-25% of hydrofluoric acid, 10-20% of nitric acid, 0.01-0.083% of sodium butylnaphthalene sulfonate, 0.075-0.45% of PE6400, and the balance of ultrapure water. Further preferably, the etching solution further comprises 0.017 to 0.1% of 1-butyl-3-methylimidazole tetrafluoroborate in terms of mass fraction. Still more preferably, the etching solution further comprises 0.033-0.1% of 4-mercaptobutyric acid by mass fraction. Preferably, the etching solution comprises, by mass, 15-25% of hydrofluoric acid, 12-16% of nitric acid, 0.03-0.06% of sodium butylnaphthalene sulfonate, 0.09-0.3% of PE6400, 0.02-0.06% of 1-butyl-3-methylimidazole tetrafluoroborate, 0.045-0.85% of 4-mercaptobutyric acid, and the balance of ultrapure water. The quartz crystal etching liquid can be used for quartz crystal V-shaped etching. By adding the additive into hydrofluoric acid and nitric acid, the etching solution can laterally etch to generate a symmetrical V-shaped structure, so that residual protrusions after quartz crystal etching are obviously reduced, the surface is smoother, and the roughness is lower. This helps to improve the performance and stability of the resonator. The additive is used for improving etching effect, controlling side etching shape, reducing roughness and reducing residue. The sodium butylnaphthalene sulfonate prevents aggregation and deposition of particles generated in the etching process, and maintains the clarity and uniformity of the etching solution. PE6400 has both hydrophilicity and hydrophobicity, and plays roles of dissolution assistance, dispersion and defoaming. The two can obviously reduce the residual protrusion after quartz crystal etching, reduce the roughness and make the surface smoother. The cooperation of the 1-butyl-3-methylimidazole tetrafluoroborate and the 4-mercaptobutyric acid can control quartz undercut to generate a symmetrical V-shaped structure. Compared with the prior art, the invention has the advantages that: 1. symmetrical side etching structure, the etching liquid can generate symmetrical V-shaped structure by side etching, and the consistency of frequency is ensured. 2. The etching residues are reduced, namely the residues on the quartz crystal after etching are obviously reduced and the etching quality is improved by adding the bi-component additive into the etching solution. 3. The surface flatness is improved, namely the surface of the etched quartz crystal is smoother, and the subsequent process and the performance improvement of the resonator are facilitated. 4. The etching solution has stable components, is easy to control, and is beneficial to improving the stability and reliability of the manufacturing process of the resonator. Drawings FIG. 1 shows the etching effect of the etching solution of the present invention. Detailed Description The following description of the embodiments of the present invention will clearly and fully describe the technical solutions of the embodiments of the present invention, and the embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, based on the embodiments of the invention, which are obtained by a person of ordinary skill in the art without making any inventive effort, are