CN111431498B - A kind of conductive polymer solution for crystal resonator and its application - Google Patents

Abstract

The invention relates to the technical field of electronic components and discloses a conductive polymer solution for a crystal resonator and application thereof, wherein the conductive polymer solution comprises the following raw material components in parts by mass: 80 to 98.5 portions of polar proton solution; 1-10 parts of modified polythiophene aqueous dispersion; 0.1 to 3 parts of nano graphite sheet aqueous dispersion; 0.01 to 0.05 part of dispersing agent; 0.01 to 0.05 portion of leveling agent; 0.01 to 0.05 portion of wetting agent. The nano graphite sheet with good water dispersibility is added into the modified polythiophene aqueous dispersion, the defect that micron-sized filler influences the flatness of the conductive coating is overcome, the wetting agent ensures that the conductive polymer solution has good wettability to the wafer, and the surface regularity of the coating and the spraying efficiency are improved. The conductive polymer solution is sprayed on the surface of the wafer through a spray gun to prepare the quartz wafer for the resonator, the surface of which is coated with the conductive polymer electrode. The wafer has electrodes with good conductivity, the surface resistance of the electrode can be as low as 232 omega, and the wafer is expected to replace metal silver to be applied to the field of crystal resonators.

Description

A kind of conductive polymer solution for crystal resonator and its application

technical field

The invention relates to the technical field of electronic components, in particular to a conductive polymer solution for a crystal resonator and an application thereof.

Background technique

A crystal resonator refers to a quartz crystal resonator made of quartz material, commonly known as a crystal oscillator. It is an electromechanical device made of a quartz crystal with little power loss that is precisely cut and ground, plated with electrodes and welded with leads. The function of frequency, with the characteristics of stability and good anti-interference performance, is widely used in various electronic products. If the crystal resonator is energized, it will generate mechanical oscillation, and its oscillation frequency is closely related to their shape, material, cutting direction, etc., and the electrode size used in different frequency points of the quartz crystal oscillator is different.

In the prior art, the crystal resonator is energized by plating silver on the surface of the quartz crystal resonator, and then connecting with electrodes. Metal silver has good electrical conductivity and oxidation stability, and is currently a common raw material for electrodes plated on the surface of crystal resonators. The electrode material generally uses silver with a purity of more than 99.99%. In order to improve the adhesion strength of the electrode, a small amount of chromium (Cr) or nickel (Ni) is plated before silver plating.

CN103684318A discloses a method for manufacturing a surface silver-plated quartz crystal resonator, which includes the following steps in turn: (1) cutting of the quartz crystal; (2) grinding of the wafer; (3) measuring the angle by X-ray; (4) sticking the mound (5) cutting and grinding width; (6) chemical material and chamfering; (7) frequency sorting; step (8) corrosion, by using a chemical solvent to corrode the surface of the wafer; it is characterized in that: it also includes the step (9) cleaning, using a cleaning agent to remove the plaster, oil stains and chemical residues of the chip, and then further cleaning with clear water; (10) silver plating, plating a silver layer on the surface of the chip according to the size of the electrode; (11) putting it on the shelf Glue dispensing and silver glue curing, place the silver-plated wafer on a fixed support, fix it with silver glue, and then cure it at a temperature of 100-120°C. The silver layer of the present invention is uniform, easy to fall off, convenient for fixing silver glue and connecting with electrodes, not easy to be damaged, and has long service life.

CN 102832902A discloses a quartz crystal resonator and a processing method thereof, including a shell, a base, pins, spring sheets, conductive glue, a coating electrode, and a wafer; the coating electrode includes a basic electrode and a fine-tuning electrode connected thereto; a coating The wafer in which the electrodes are attached to the wafer surface sequentially includes a lower chromium plating layer, a silver plating layer and an upper chromium plating layer from the inside to the outside. The invention can improve the parasitic response characteristics of the quartz crystal resonator, and greatly improve the performance and quality of the produced quartz crystal resonator.

However, the processes of silver plating and chrome plating in the prior art all require high technological requirements and high requirements for the purity of metal raw materials. At the same time, the processes of silver plating and chromium plating on the crystal surface are complex and costly. The development of new electrode materials that are easy to spray and have high conductivity is a key issue to improve the current wafer preparation process.

Contents of the invention

The present invention aims to solve the problems of high technical requirements, complex process and high cost in the prior art of crystal surface silver plating, and provides a polymer solution that is easy to spray and has high conductivity. A conductive thin film is formed on the crystal surface to replace metal in the field of crystal resonators.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A conductive polymer solution for a crystal resonator, in 100 parts by mass, comprising the following raw material components:

80-98.5 parts of polar proton solution;

1-10 parts of modified polythiophene aqueous dispersion;

0.1-3 parts of nano-graphite flake aqueous dispersion;

Dispersant 0.01～0.05 parts;

Leveling agent 0.01 ~ 0.05 parts;

0.01-0.05 parts of wetting agent;

The mass ratio of the modified polythiophene water dispersion to the nano-graphite water dispersion is 100:50˜100:1.

Preferably, the mass ratio of the modified polythiophene aqueous dispersion to the nano-graphite flake aqueous dispersion is 100:30 to 100:5. In this ratio, the obtained conductive polymer solution has better conductivity. The wafer prepared by it has lower resistance.

The polar proton solution is a mixed solution of a polar organic solvent and water, and the polar organic solvent includes alcohol solvents, ketone solvents, N-methylpyrrolidone (NMP) and other polar protons commonly used in the art. solvent. In the polar protic solution, the mass part of water in the conductive polymer solution is 40-70 parts.

Described alcoholic solvent includes methanol, ethanol, butanol, isopropanol, glycerol, ethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol etc.; Described ketone solvent includes acetone, methyl ethyl ketone, Methyl isobutyl ketone, etc.

By adjusting the solvent components, the dispersion stability of the modified polythiophene and nano-graphite sheets in the solvent, the wettability of the solvent to the wafer and the volatilization speed of the solvent can be improved. Preferably, the polar organic solvent is ethanol. The solvent volatilizes quickly, and the conductive polymer solution is less likely to condense when sprayed on the surface of the wafer, and has better wettability to the wafer.

The modified polythiophene aqueous dispersion is an aqueous dispersion of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), wherein poly(3,4-ethylenedioxythiophene )-poly(styrene sulfonic acid) has an average particle diameter of 50-100 nm, and a solid content in water of 0.5-2.0%. Preferably, the modified polythiophene aqueous dispersion is CleviosPH 1000 product from Heraeus, Germany.

The average particle size of the nano graphite flakes in the aqueous dispersion of the nano graphite flakes is 10-500 nm, and the solid content in water is 0.1-10%. The nano-graphite flakes have good water dispersibility and are stable in polar proton solutions. The obtained conductive polymer solution is sprayed on the wafer to form a thin film. The nano-graphite flakes in the film are evenly distributed and have good conductivity.

The dispersant is one or more of commonly used surfactants in the field, such as one or more of cationic surfactants, anionic surfactants, nonionic surfactants, and amphoteric surfactants.

The cationic surfactants include amine salt cationic surfactants, quaternary ammonium salt cationic surfactants, cationic polymer surfactants and the like.

Further, the amine salt type cationic surfactant includes octadecylamine hydrochloride, dioctadecylamine hydrochloride, N,N-dimethyloctadecylamine hydrochloride, polyacrylamide hydrochloride, etc.

Further, the quaternary ammonium salt type cationic surfactant includes dioctadecyl dimethyl ammonium chloride, octadecyl dimethyl benzyl ammonium chloride, stearylamide dimethyl propyl Ammonium Chloride, Octadecyltrimethylammonium Chloride, Octadecyltrimethylammonium Bromide, Cetyltrimethylammonium Chloride, Cetyltrimethylammonium Bromide, Dodecyltrimethylammonium Bromide Alkyl Trimethyl Ammonium Chloride, Lauryl Trimethyl Ammonium Bromide, Lauryl Dimethyl Benzyl Ammonium Chloride, Oleamide Methyl Hydroxypropyl Ammonium Chloride, Erucamide Propyl trimethyl ammonium chloride etc.

Further, the cationic polymer surfactant includes polyethyleneimine, polyvinylpyrrolidone, quaternized polyacrylamide and the like.

Described anion surfactant comprises alkyl sodium sulfate, alkyl sodium sulfonate, sodium alkyl ether sulfate, triethanolamine alkyl sulfate, triethanolamine alkyl ether sulfate, ammonium alkyl sulfate, ammonium alkyl ether sulfate, alkyl ether ammonium sulfate, Sodium ether phosphate, sodium fluoroalkyl carboxylate, etc.

Described nonionic surfactant comprises polyoxyethylene alkyl ether, polyoxyethylene phenyl ether, polyoxyethylene alkyl ester, propylene glycol-oxypropylene copolymer, perfluoroalkyl ethylene oxide adduct, 2 -Ethylhexanol ethylene oxide adduct, etc.

The amphoteric surfactants include alkyl aminoacetic acid betaine, alkyl amidoacetic acid betaine, imidazole betaine and the like.

Since the surface of the nano-graphite sheet contains certain hydroxyl or carboxyl groups, it presents weak electronegativity, so the dispersant of the present invention is preferably a cationic surfactant, which can neutralize the electronegativity of the nano-graphite sheet, making it more stable to disperse in the solution.

Further preferably, the dispersant is polyethyleneimine, which exists as polycation in water, can neutralize or adsorb all anionic substances, and the amino group contained on its molecular chain can react with carboxyl to generate hydrogen bond, It reacts with carboxyl group to generate ionic bond, and reacts with carbonyl group to generate covalent bond. Polyethyleneimine can have a stronger interaction with nano-graphite flakes, which is beneficial to the dispersion of nano-graphite flakes in aqueous solution.

The leveling agent is an acrylic copolymer leveling agent, a silicone leveling agent or a fluorocarbon surfactant.

Preferably, the leveling agent is an acrylic copolymer leveling agent. This type of product is commonly used in solvent-based and water-based coating systems. It relies on the principle of similar compatibility to accumulate on the surface of the coating, which greatly reduces the viscosity of the polymer conductive solution system. Excellent surface tension, especially to improve the wettability of the substrate and prevent shrinkage.

Further preferably, the leveling agent is BYK381, an ionic acrylate copolymer solution from BYK, Germany.

The wetting agent is a silicone-based gemini surfactant or an acetylene glycol-based gemini surfactant. Since the surface tension of the conductive polymer solution is between 7×10 ^-4 and 8×10 ^-4 N·cm ^-1 , which is slightly higher than that of the quartz wafer (approximately 7×10 ^-4 N·cm ^-1 ) , so the wetting effect of the conductive polymer solution on the quartz wafer is not good. Adding a wetting agent can cooperate with the leveling agent to reduce the surface tension of the conductive polymer solution, promote the good infiltration of the conductive polymer solution on the quartz crystal, prevent surface defects such as shrinkage cavities or edge shrinkage, and increase the fluidity and flow of the solution. Flatness and adhesion.

Preferably, the wetting agent is an acetylenic diol-based gemini surfactant, which can not only reduce the equilibrium and dynamic surface tension, but also significantly improve fluidity and leveling, and easily enter difficult-to-wet substrates Surface, improve the wettability of the conductive polymer solution to the quartz wafer.

Further preferably, the wetting agent is Dynol 607 from American Gas Company.

Preferably, the dispersant is a cationic surfactant, the leveling agent is an acrylic copolymer leveling agent, and the wetting agent is an acetylenic diol gemini surfactant. Under this combination, the wettability, fluidity, and fluidity of the conductive polymer solution are better.

Further preferably, the dispersant is polyethyleneimine, the leveling agent is ionic acrylate copolymer solution BYK381 from BYK, Germany, and the wetting agent is Dynol 607 from American Gas Company. Under this combination, the performance of the conductive polymer solution is optimal.

When the conductive polymer solution for a crystal resonator provided by the present invention is applied to a crystal resonator, the conductive polymer solution is coated on the surface of a wafer by spraying with a spray gun.

Since the main component of the conductive polymer solution is water, the wetting effect of water on the quartz wafer is poor, and water droplets will condense on the surface of the quartz wafer during the spraying process, resulting in uneven coating surface. In addition to adding leveling agent and wetting agent to the solution to improve the wetting effect, the temperature of the quartz wafer should be increased to accelerate the rapid volatilization of the spraying liquid. The suitable temperature range for the quartz wafer is 100-150°C, preferably 120°C.

At the same time, try to prevent the solution from condensing into water droplets on the surface of the quartz wafer during the spraying process of the spray gun, resulting in uneven coating surface. If droplets appear on the surface of the wafer, the spraying should be stopped immediately, and the wafer should be heat-treated in an oven at 100-150°C to make the spraying liquid on the surface volatilize and form a film; then continue spraying, and after the spraying is completed, put the wafer into the oven Treat at 100-150°C for 2-15 minutes to remove the solvent. The template is removed to obtain a quartz wafer for a resonator whose surface is coated with conductive polymer electrodes.

The wafer has an electrode with good electrical conductivity, and its surface resistance can be as low as 232Ω. The crystal resonator prepared based on the conductive polymer solution of the present invention as an electrode can start vibration smoothly, and the resonant frequency of the resonator can be 3.99～4.02MHz. It is expected to replace metallic silver in the field of crystal resonators.

Compared with the prior art, the present invention has the following beneficial effects:

(1) Adding nano-scale graphite with good water dispersibility to the modified polythiophene aqueous dispersion overcomes the shortcoming that the micron-scale filler affects the flatness of the conductive coating;

(2) The nano-graphite used has good dispersibility in water, adding a dispersant to ensure the dispersion stability of the nano-graphite in the aqueous solution;

(3) By adding a wetting agent and adjusting the solvent ratio, ensure that the conductive polymer solution has good wettability and proper volatility to the chip, and improve the surface regularity and spraying efficiency of the coating.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. Modifications or equivalent replacements made by those skilled in the art on the basis of understanding the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall fall within the protection scope of the present invention.

The raw materials used in the following embodiments are all commercially available products. The modified polythiophene aqueous dispersion is Clevios PH 1000 from Germany, with a solid content of 1.0%; the nano-graphite flakes are produced by a domestic manufacturer, with an average particle size of 10-100nm and a solid content of 10%; the dispersant Polyethyleneimine is selected as a general commercially available product; the leveling agent is BYK381, an ionic acrylate copolymer solution from BYK, Germany; the wetting agent is Dynol 607, an acetylene glycol-based gemini surfactant from American Gas Company.

Example 1

Take ethanol aqueous solution, modified polythiophene aqueous dispersion, nano graphite sheet aqueous dispersion, polyethyleneimine, BYK381 and Dynol 607 to prepare conductive polymer solution, wherein the mass proportion of each component is respectively: water content is 40% , the content of ethanol is 49.36%, the content of modified polythiophene aqueous dispersion is 10%, the content of nanographite flake aqueous dispersion is 0.6%, the content of polyethyleneimine is 0.02%, the content of BYK381 is 0.01%, and the content of Dynol 607 is 0.01 %.

Before spraying, first place the wafer on a specific template, heat it in an oven to 120°C, then take out the wafer, and use a spray gun to spray the prepared conductive polymer solution. During the spraying process, always pay attention to the wetting of the conductive polymer solution on the wafer surface. In wet conditions, if droplets appear on the surface of the wafer, stop spraying immediately, put the wafer in a 120°C oven for heat treatment for 1min, then take out the wafer and continue spraying until 1.5g of conductive polymer solution is sprayed on one side of the wafer. Then adopt the same method to spray 1.55g conductive polymer solution on the other side of the wafer. After spraying, the wafer was placed in an oven at 120° C. for 10 minutes to remove the solvent. Finally, the template is removed to obtain a quartz wafer for a resonator whose surface is coated with conductive polymer electrodes.

Embodiment 2～3

According to the spraying process of Example 1, the conductive polymer solution prepared in Example 1 was sprayed on the surface of the wafer, and the spraying amount of the wafer on one side was 2.5g (Example 2) and 5g (Example 3).

Example 4

Take ethanol aqueous solution, modified polythiophene aqueous dispersion, nano graphite sheet aqueous dispersion, polyethyleneimine, BYK381 and Dynol 607 to prepare conductive polymer solution, wherein the mass proportion of each component is respectively: water content is 50% , the content of ethanol is 39.36%, the content of modified polythiophene aqueous dispersion is 9%, the content of nanographite flake aqueous dispersion is 1.6%, the content of polyethyleneimine is 0.02%, the content of BYK381 is 0.01%, and the content of Dynol 607 is 0.01 %.

According to the spraying process of Example 1, the conductive polymer solution prepared in this example was sprayed on the surface of the wafer, and the amount of spraying on one side of the wafer was 2.5 g.

Example 5

Take ethanol aqueous solution, modified polythiophene aqueous dispersion, nano-graphite sheet aqueous dispersion, polyethyleneimine, BYK381 and Dynol 607 to prepare conductive polymer solution, wherein the mass proportion of each component is respectively: water content is 70% , the content of ethanol is 19.36%, the content of modified polythiophene aqueous dispersion is 8.5%, the content of nanographite flake aqueous dispersion is 2.1%, the content of polyethyleneimine is 0.02%, the content of BYK381 is 0.01%, and the content of Dynol 607 is 0.01% %.

According to the spraying process of Example 1, the conductive polymer solution prepared in this example was sprayed on the surface of the wafer, and the amount of spraying on one side of the wafer was 2.5 g.

Comparative example 1

The modified polythiophene aqueous dispersion was used to prepare a conductive polymer solution, wherein the modified polythiophene aqueous dispersion accounted for 10% by mass and water accounted for 90%. According to the spraying process of Example 1, the conductive polymer solution prepared in this comparative example was sprayed on the surface of the wafer, and the amount of spraying on one side of the wafer was 2.5 g.

Table 1 summarizes the proportions of each component in the conductive polymer solutions of Examples 1 to 5 and Comparative Example 1, and the spraying amount on one side of the wafer.

Table 1 The content of each component in the conductive polymer solution and the spraying amount of the wafer on one side

The wafers prepared in Examples 1 to 5 and Comparative Example 1 were tested for surface resistance and resonant frequency, using Agilent 34401A multimeter to test electrode impedance, using E5100 analyzer and 250B network analyzer to measure the resonant frequency of the crystal, and the test results As shown in table 2. From the data in Table 2, it can be found that the wafer surface resistance prepared by the conductive polymer solution of Examples 1 to 5 decreases with the increase of spraying amount; The content of non-toxic polythiophene aqueous dispersion, the surface resistance of the chip is further reduced, the lowest can reach 232Ω, and the conductivity is excellent;

Simultaneously, it can be seen that under the unilateral spraying amount of 2.5g, the chip resistance of the conductive polymer solution sprayed with only modified polythiophene in Comparative Example 1 is 2349 Ω, while the chip surface resistance prepared in Example 2 is only 1592 Ω, indicating that The addition of nano-graphite flakes can greatly improve the conductivity of the solution. The crystal resonators prepared based on the above-mentioned conductive liquid as electrodes can start vibration smoothly, and the resonant frequency of the resonator can be adjusted between 3.99 and 4.02MHz, which is expected to replace metallic silver. Used in the field of crystal resonators.

Chip resonant frequency and surface resistance prepared by each embodiment of table 2

serial number Resonant frequency (Hz) Surface resistance (Ohms) Example 1 4,023,493.00 3576.21 Example 2 4,016,154.10 1592.55 Example 3 3,999,527.78 1098.80 Example 4 4,016,232.10 920.53 Example 5 4,016,737.91 232.16 Comparative example 1 4,017,017.52 2349.22

Claims (6)

1. a conductive polymer solution for a crystal resonator, characterized in that, in 100 parts by mass, comprising the following raw material components: 80-98.5 parts of polar proton solution; 1-10 parts of modified polythiophene aqueous dispersion; 0.1-3 parts of nano-graphite flake aqueous dispersion; Dispersant 0.01～0.05 parts; Leveling agent 0.01 ~ 0.05 parts; 0.01-0.05 parts of wetting agent; The modified polythiophene aqueous dispersion is an aqueous dispersion of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), wherein poly(3,4-ethylenedioxythiophene )-poly(styrene sulfonic acid) has an average particle diameter of 50 to 100nm, and a mass content in water of 0.5 to 2.0%; the mass ratio of the modified polythiophene water dispersion to the nanographite sheet water dispersion is 100:30～100:5; Described dispersant is polyethyleneimine; The polar protic solution is a mixed solution of a polar organic solvent and water, and the polar organic solvent includes any one or more of methanol, ethanol, and acetone. 2. The conductive polymer solution for crystal resonators according to claim 1, wherein the aqueous dispersion of graphite nanosheets is an aqueous dispersion of graphite nanosheets, and the average particle diameter of graphite nanosheets is 10 to 500nm , the mass content in water is 0.1-10%. 3. The conductive polymer solution for crystal resonators according to claim 1, wherein the leveling agent is an acrylic copolymer leveling agent, a silicone leveling agent or a fluorocarbon surfactant. 4 . The conductive polymer solution for crystal resonators according to claim 1 , wherein the wetting agent is an organosilicon-based gemini surfactant or an acetylene glycol-based gemini surfactant. 5 . 5. The conductive polymer solution for crystal resonators according to claim 1, wherein the leveling agent is an acrylic acid copolymer leveling agent, and the wetting agent is an acetylenic glycol class gemini type surface active agent. 6. The application of the conductive polymer solution for a crystal resonator according to any one of claims 1 to 5 in a crystal resonator, characterized in that, the conductive high polymer solution according to any one of claims 1 to 5 is sprayed by a spray gun. The molecular solution is coated on the surface of the wafer.