CN103219243A - Manufacturing method of patterning metal lines - Google Patents

Abstract

The invention relates to the field of electronic manufacturing, and discloses a method for preparing a patterned metal circuit. In the present invention, a substrate is provided; the patterned dopamine substrate surface is prepared on the substrate by using the prepared activation solution and photolithography or printing technology; wherein, dopamine substances are added to the activation solution; the patterned substrate is placed on In the metal plating solution, a layer of metal is deposited on the exposed dopamine-like substances on the surface of the substrate; a reducing agent is added to the metal plating solution. The patterned metal circuit is a patterned conductive film or fine circuit. If the patterned conductive film to be prepared is a single-sided patterned conductive film, in the step of preparing the surface of the patterned dopamine base on the substrate, one side of the substrate is coated with a barrier layer that cannot react with metals and then coated on the substrate. Prepare the surface of the patterned dopamine-based substrate on the other side; alternatively, the non-patterned side of the substrate is coated with a barrier layer prior to the step of placing the patterned substrate in the metal plating solution.

Description

Method for preparing patterned metal circuit

technical field

The invention relates to the field of electronic manufacturing, in particular to the preparation technology of patterned metal circuits.

Background technique

The preparation of metal lines on insulating substrates is a very important production link in the electronics/microelectronics industry. In recent years, with the development of microelectronics and semiconductor technology, people's requirements for metal lines are increasing day by day. The pursuit of low-cost manufacturing technology has greatly stimulated the enthusiasm of researchers to develop new metal circuit preparation technology. The traditional process is to etch away the metal not covered by the photoresist after photolithography to form the circuit. This "subtractive" process causes various problems such as metal waste, cost increase, and environmental pollution. With the gradual miniaturization of electronic devices In the direction of development, the traditional "subtraction" process is difficult to meet the requirements of circuit refinement.

At the same time, transparent conductive films can generally be divided into two types: patterned and non-patterned, and the former can be realized by forming a metal circuit grid of a certain shape. At present, the market-leading transparent conductive film indium tin oxide (ITO) film has problems such as brittleness and lack of flexibility, high process cost, high price of indium, and limited resources. There is an urgent need to develop new flexible conductive transparent films to meet future optoelectronic devices. development needs.

Common methods for preparing patterned transparent conductive films include inkjet printing, offset printing, roll-to-roll printing, and the like. Its production method is usually to prepare conductive ink from materials with a particle size of nanometer scale, such as silver nanowires, and then print the conductive ink on the surface of a flexible transparent substrate, and form the required conductive network after sintering. The width of the network lines is below the resolution of the human eye, and the area without lines is the light-transmitting area. The surface resistance and light transmittance of the transparent conductive film can be controlled within a certain range by changing the width, spacing and geometric shape of the lines. However, the use of printing technology to make wire grids requires the preparation of micro-nano-scale conductive inks in advance, and sintering is required to form conductive lines. The stabilizer coated on the periphery of micro-nano materials usually needs to be decomposed and desorbed at a high temperature of 250°C. In order to obtain better conductivity, the current ink sintering temperature is high, which is not suitable for some cheap and low glass transition temperature. polymer substrate, and lowering the sintering temperature will sacrifice the conductivity of the film due to the residue of the stabilizer. In addition, it is difficult to control the thickness of the film layer at a lower nanometer level by printing, and the conductive grid is a protrusion exposed on the surface of the substrate, which increases the surface roughness of the product, and the conductive circuit is adhered to the substrate after sintering. If it is not attached firmly, it is prone to drastic changes in conductivity when it is bent.

Contents of the invention

The object of the present invention is to provide a method for preparing a patterned metal circuit, so that the preparation of a patterned conductive film or a fine circuit can be realized without sintering at room temperature, and while meeting the requirements of film conductivity and light transmittance, it can Realize the effective adhesion of metal wires and different substrates, and effectively improve the roughness of the film surface.

In order to solve the above technical problems, the present invention provides a method for preparing a patterned metal circuit, comprising the following steps:

provide a base;

Prepare a patterned dopamine substrate surface on the substrate by using the prepared activation solution and photolithography or printing technology; wherein, dopamine substances are added to the activation solution;

The patterned substrate is placed in a metal plating solution, and a layer of metal is deposited on the exposed dopamine substance on the surface of the substrate; a reducing agent is added to the metal plating solution;

The patterned metal circuit is a patterned conductive film or a fine circuit;

Wherein, if the patterned conductive film to be prepared is a single-sided patterned conductive film, then

In the step of preparing a patterned dopamine-based substrate surface on the substrate, a barrier layer that cannot react with metal is coated on one side of the substrate, and then the patterned dopamine-based substrate surface is prepared on the other side of the substrate; or , before the step of placing the patterned substrate in a metal plating solution, coating the unpatterned side of the substrate with the barrier layer.

Compared with the prior art, the embodiment of the present invention forms a layer of patterned dopamine nano-film on the substrate through photolithography (or printing) technology and the prepared activation solution, and then places the patterned substrate in the metal plating solution In the process, a layer of metal is deposited on the bare dopamine on the surface of the film by utilizing the excellent adhesion and reducibility of dopamine. Due to the unique adhesion and reducibility of dopamine substances, the metal is only formed on the exposed parts of dopamine substances, so as to realize the selective deposition of metals on the substrate surface, and there is no need for additional sensitization or seed layer generation during electroless plating, and the process is simple and time-consuming. , friendly to the environment, and the metal layer adheres firmly to the substrate. In addition, since dopamine can be deposited on the surface of various materials under very mild conditions, it is suitable for various substrates, and the whole process is carried out at room temperature. Moreover, since a reducing agent is added to the metal plating solution, the continuity and conductivity of the metal film are ensured during electroless metal plating. In addition, since the thickness of metal wires can be adjusted from nanometers to micrometers, it can not only meet the needs of improving the surface roughness of conductive films, but also meet the requirements of fine conductive lines with a certain thickness.

It should be noted that when the patterned conductive film to be prepared is a single-sided patterned conductive film, a barrier layer that cannot react with metals is coated on one side of the substrate, and then a patterned dopamine-based substrate surface is prepared on the other side of the substrate. or, before the step of placing the patterned substrate in the metal plating solution, the non-patterned side of the substrate is coated with the barrier layer, so as not to deposit a layer of metal on the other side in the subsequent electroless plating, further Metal waste is avoided.

Preferably, the reducing agent is one of the following or a mixture of any combination thereof: glucose, formaldehyde, tartaric acid, sodium potassium tartrate, dimethylaminoborane, sodium borohydride, hydrazine dihydrochloride, hydrazine sulfate, hydrazine, sodium hypophosphite , Glyoxylic acid, malic acid, sodium hypophosphite, citric acid, sodium citrate, ascorbic acid, N,N-dimethylformamide, ethylene glycol, glutaraldehyde.

Preferably, the metal plating solution is a commercial metal plating solution, or, the metal plating solution is composed of the following components: metal salt, solvent water, reducing agent, additive; wherein, the metal salt is copper salt, silver salt and other metal salts. This enables the implementation of the present invention to have a wide range of application scenarios.

Preferably, the additive is one of the following or a mixture of any combination thereof: ethanol, methanol, disodium edetate, ethylenediamine, triethanolamine, thiourea, bipyridine, polyethylene glycol, polyvinyl alcohol, poly Pyrrolidone, sodium lauryl sulfate, sodium citrate, sodium acetate, sodium pyrophosphate, potassium ferrocyanide, lead sulfate, ammonium sulfate, lactic acid, succinic acid, citric acid, propionic acid, glycolic acid, boric acid, tartaric acid Salt, Sodium Hydroxide, Potassium Hydroxide, Ammonia. The additive has the characteristics of stabilizing the plating solution, regulating the properties of the plating layer, and adjusting the conditions of the silver plating process.

Preferably, the lithography technique includes any one of the following lithography techniques: ultraviolet lithography, extreme ultraviolet lithography, electron beam lithography, ion beam lithography, X-ray lithography, and imprint lithography; the imprint lithography These include thermal embossing, UV-curable nanoimprinting, and microcontact printing. Since microcontact printing can directly print the substance coated on it on the substrate similar to a stamp, the process is simpler than the traditional one, and the minimum line width obtained is smaller, especially suitable for lines below a few hundred nanometers, which are visible to the naked eye. Invisible scene.

Preferably, the printing technique comprises any of the following: printing, screen printing, inkjet printing, letterpress printing, gravure printing, offset printing, thermal transfer printing, xerography, roll-to-roll printing. Preferably, the substrate is a transparent, translucent or opaque flexible or rigid substance. The present invention can be applied to the preparation of metal grid transparent metal circuits, so as to be applied in industries such as solar energy, OLED, display, optical devices, packaging, IC manufacturing, PCB manufacturing and the like.

Description of drawings

1 is a flowchart of a method for preparing a patterned metal circuit according to a first embodiment of the present invention;

2 is a schematic diagram of a process for patterning a metal circuit using a conventional photolithography process according to the first embodiment of the present invention;

3 is a schematic diagram of a process for preparing a metal circuit pattern using template imprinting technology according to the first embodiment of the present invention;

Fig. 4 is an optical microscope photo of the metal grid of the transparent conductive film prepared according to the first embodiment of the present invention;

5 is a partial SEM image of a metal grid of a transparent conductive film prepared according to the first embodiment of the present invention;

Fig. 6 is an optical microscope photo of a fine circuit prepared according to the first embodiment of the present invention;

Fig. 7 is a partial SEM image of a fine circuit prepared in the first embodiment of the present invention;

FIG. 8 is a flowchart of a method for preparing a patterned metal circuit according to a second embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, various embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that, in each implementation manner of the present invention, many technical details are provided for readers to better understand the present application. However, even without these technical details and various changes and modifications based on the following implementation modes, the technical solution claimed in each claim of the present application can be realized.

The first embodiment of the present invention relates to a method for preparing a patterned metal circuit, such as preparing a transparent conductive film or a fine circuit. The specific process is shown in Figure 1.

In step 101, a substrate is provided. The substrate can be a transparent, translucent or opaque flexible or rigid substance. In addition, the substrate needs to be pre-treated, cleaned and dried. In this embodiment, the shape of the substrate includes but is not limited to a sheet shape, and is applicable to metals, inorganic non-metals, polymers, composite materials, and the like.

Next, in step 102, a patterned dopamine substrate surface is prepared on the substrate by using photolithography technology and the prepared activation solution; wherein, dopamine substances are added to the activation solution.

Specifically, first, an activation solution needs to be prepared, and dopamine substances are dissolved in it, and an oxidant can be added as needed. In this embodiment, the pH buffering substance in the activation solution is sodium dihydrogen phosphate-citric acid buffer, disodium hydrogen phosphate-sodium dihydrogen phosphate buffer, barbital sodium hydrochloride buffer, Tris-hydrochloric acid buffer, Any of the sodium carbonate-sodium bicarbonate buffers. The pH value of the activation solution is 2-11, preferably 7-9, and the solvent is water. When the substrate to be treated is incompatible with water, organic solvents such as alcohols, ethers, and ketones can be optionally added amides, etc.

The dopamine substances added in the activation solution are dopamine substances of any of the following structural formulas, or polymers, ligands, acid salts or basic salts of dopamine substances of any of the following structural formulas:

Wherein, the R group is an alkyl group or a substituted alkyl group; the R ₁ and R ₂ groups are H, an alkyl group or a substituted alkyl group. For example: 3,4-Dihydroxyphenylalanine (DOPA/DOPA), 3,4-Dihydroxyphenylethylamine (Dopamine/DA), Tyrosine (Tyrosine), Dopaquinone (Dopaquinone), Dopaminequinone (Dopaminequinone), Cyclodopa (Cyclodopa/Leucodopachrome), Cyclodopa (Leucodopaminechrome), Dopachrome (Dopachrome), Dopaminechrome (Dopaminechrome), Cysteinyldopa (Cysteinyldopa), 5,6-dihydroxyindole , Eumelanin (Eumelanin), Pheomelanin (Pheomelanin), epinephrine (Epinephrine), norepinephrine (Norepinephrine) in one or more of the mixture.

Next, place the substrate in the prepared activation solution, let it stand for a period of time, and immerse in the activation solution for 1 second to 100 hours, and the reaction temperature does not exceed 100°C. Wherein, the activation solution is exposed to the air or fed with oxygen or the following oxidative substances are added, including ammonium persulfate, sodium periodate, sodium perchlorate, copper sulfate, etc.; the dopamine-like substances modify the substrate in water, or other in inorganic and organic solvents.

Then, the substrate is taken out from the activation solution (at this time, the surface of the substrate is loaded with dopamine substances), and the substrate on the side to be patterned is subjected to photolithography to obtain a patterned surface of the dopamine substrate. Those skilled in the art can understand that before using the photolithography technology and the prepared activation solution to prepare the patterned dopamine-based substrate surface on the substrate, the pattern that needs to be formed on the substrate can be designed according to the requirements of light transmittance and electrical conductivity. For example, the line width and line spacing are designed according to the requirements of light transmittance and electrical conductivity, and the designed pattern is composed of crossing or non-crossing straight lines, curves or broken lines. Materials used to form patterns (that is, substances used in lithography or printing) include photoresist, embossing glue, ink, and various substances that do not react with metals.

In this embodiment, the photolithography technology includes any of the following photolithography technologies:

Ultraviolet lithography, extreme ultraviolet lithography, electron beam lithography, ion beam lithography, X-ray lithography, and imprint lithography; among them, imprint lithography includes thermal embossing, UV-cured nanoimprinting, and microcontact printing. When microcontact printing is used, the material to be patterned can also be directly imprinted on the surface-loaded dopamine-like substrate by using a patterned polymer stamp to obtain a substrate with a patterned dopamine-like substrate surface.

Next, in step 103, the patterned substrate is placed in a metal plating solution, and a layer of metal is deposited on the exposed dopamine-like substances on the surface of the substrate, wherein a reducing agent is added to the metal plating solution. The reducing agent is one of the following or a mixture of any combination thereof:

Glucose, formaldehyde, tartaric acid, potassium sodium tartrate, dimethylaminoborane, sodium borohydride, hydrazine dihydrochloride, hydrazine sulfate, hydrazine, sodium hypophosphite, glyoxylic acid, malic acid, sodium hypophosphite, citric acid, Sodium citrate, ascorbic acid, N,N-dimethylformamide, ethylene glycol, glutaraldehyde.

Specifically, the metal plating solution is a commercial metal plating solution, or, the metal plating solution is composed of the following components: metal salt, solvent water, reducing agent, additive; wherein, the metal salt is copper salt or silver salt . Silver salt can be one of the following or a mixture of any combination: silver nitrate, silver perchlorate, silver sodium cyanide, silver potassium cyanide, silver tetrafluoroborate, silver acetate, silver sulfate, silver bromide, silver chloride , silver oxide, silver carbonate, silver phosphate. The copper salt can be one of the following or a mixture of any combination thereof: copper sulfate, copper chloride, copper nitrate, copper acetate, copper carbonate and its hydrate, copper hydroxide, cuprous oxide, copper oxide. The additive can be one of the following or a mixture of any combination thereof: ethanol, methanol, ethylenediaminetetraacetic acid disodium, ethylenediamine, triethanolamine, ethylenediaminetetraacetic acid, thiourea, bipyridine, polyethylene glycol, poly Vinyl alcohol, polypyrrolidone, sodium lauryl sulfate, sodium citrate, sodium acetate, sodium pyrophosphate, potassium ferrocyanide, lead sulfate, ammonium sulfate, nickel sulfate, lactic acid, succinic acid, citric acid, propionic acid , glycolic acid, boric acid, tartrate, sodium hydroxide, potassium hydroxide, ammonia. The concentration of the silver salt in the plating solution is 0.001-2mol/L, the content of the reducing agent is 0.001-10mol/L, and the content of the additive is 0-20mol/L.

Because dopamine substances can adhere to the surface of various organic or inorganic substrates, and have excellent bonding performance, and because dopamine substances contain a large number of amino groups and hydroxyl groups, they can effectively adsorb metal ions and reduce them through the action of reducing agents. Therefore, a layer of metal can be deposited on the bare dopamine-like substances on the surface of the film, and the process is simple and easy.

For example, take the preparation circuit of electroless silver plating as an example. In this step, a silver salt solution with a certain concentration is prepared, and the substrate obtained after step 102 is placed in it for a period of time, and then a reducing agent is added. In order to improve the coating quality, you can Add suitable additives; remove the substrate after a period of time and wash.

Next, in step 104, substances used for photolithography or printing during the photolithography process in step 102 are removed, such as photoresist, embossing glue, ink, substances that do not react with metals, and the like.

It is worth mentioning that if it is necessary to form patterns on both sides of the substrate, the material to be patterned is patterned on both sides of the substrate by photolithography, and after step 104, a conductive film with patterns formed on both sides of the substrate is obtained .

If it is necessary to form a pattern on one side of the substrate, then in step 102, before the substrate is placed in the configured activation solution, a barrier layer that cannot react with the metal is coated on one side of the substrate, so that the side coated with the barrier layer Unable to load dopamine substances, the other side of the substrate is the side to be patterned. Alternatively, in step 102, one side of the substrate is selected as the side to be patterned, and after photolithography is completed to obtain the surface of the patterned dopamine-based substrate, the non-patterned side of the substrate is coated with a barrier layer.

After one side of the substrate is coated with a barrier layer that cannot react with metal, the surface of the patterned dopamine-based substrate is prepared on the other side of the substrate; or, after the patterned substrate is placed in a metal plating solution Before the step, the unpatterned side of the substrate is coated with a barrier layer. The barrier layer includes photoresist, embossing glue, ink and other substances that do not react with metal. In order not to deposit a layer of metal on the other side in the subsequent electroless plating, further avoiding metal waste.

In other words, one side of the cleaned substrate can be coated with a barrier layer, placed in an activation solution, and taken out after a period of time; or the cleaned substrate can be placed in an activation solution, and after a period of time is taken out, one side can be coated with a barrier layer. The desired pattern is formed on the side of the substrate not coated with the barrier layer by photolithography technology.

Since the barrier layer is coated on one side of the substrate in the process of preparing the conductive film with a single-sided pattern, in step 104, while removing the patterned material, the barrier layer also needs to be removed, as shown in Figure 2 and Figure 3 Show. The symbols in FIG. 2 are explained as follows: 210 is a substrate; 220 is a dopamine substance; 230 is a barrier layer; 240 is a photoresist; 250 is an electroless plated metal.

The preparation of a transparent conductive film with a square grid as a basic unit, the preparation of a fine silver circuit on a flexible substrate, and the preparation of a grid-shaped metal copper wire transparent conductive film will be specifically described below.

1. Prepare a transparent conductive film with a square grid as the basic unit:

(1) Design the width and spacing of grid metal lines according to the requirements of light transmittance and resistivity. In this example, the line width is 25 μm and the line spacing is 100 μm;

(2) Put the transparent PET film (substrate) with a thickness of 50 μm in acetone for ultrasonication, wash it with deionized water, and dry it;

(3) Prepare Tris-hydrochloric acid activation solution, pH = 8.5, add dopamine hydrochloride, Tris concentration 1.2mg/mL, dopamine hydrochloride concentration 2mg/mL, put into cleaned PET, reaction temperature 15°C, reaction time 0.5h , take out the PET, rinse with deionized water, and dry;

(4) Photolithography, positive resist spin coating, flipping, re-coating, pre-baking, exposure, development, post-baking;

(5) Prepare a metal plating solution, the concentration of AgNO ₃ is 0.2%, add ammonia water until the solution is just clear, add a small amount of ethanol, and the amount of glucose is twice the molar number of silver nitrate;

(6) Immerse the patterned PET in the metal plating solution, stir, take it out after 2-4 minutes, rinse with deionized water, and rinse with ethanol;

(7) Wash with photoresist stripping solution, rinse with deionized water, rinse with ethanol, and dry to obtain a regular grid of silver wires with smooth edges, as shown in Figure 4, and the sheet resistance is 9Ω/sq. The SEM (scanning electron microscope) image of the prepared metal grid part is shown in Figure 5.

2. Preparation of fine silver lines on flexible substrates:

(1) Ultrasonicate a translucent PET film with a thickness of 50 μm in acetone, wash it with deionized water, and dry it;

(2) Prepare Tris-hydrochloric acid activation solution, pH=8.5, add dopamine hydrochloride, Tris concentration 1.2mg/mL, dopamine hydrochloride concentration 2mg/mL, put into cleaned PET, reaction temperature 15°C, reaction time 0.5h , take out the PET, rinse with deionized water, and dry;

(3) Photolithography, positive resist spin coating, flipping, re-coating, pre-baking, exposure, development, post-baking;

(4) Prepare a metal plating solution, the concentration of AgNO ₃ is 0.2%, ammonia water is added until the solution is just clear, a small amount of ethanol is added, and glucose is added according to twice the molar number of silver nitrate;

(5) Put the patterned PET into the metal plating solution, stir, take it out after 2-4min, rinse with deionized water, and rinse with ethanol;

(6) Clean with photoresist stripper, deionized water, rinse with ethanol, and dry. By this method, micron-scale fine lines can be obtained, and the edges of the lines are flat (as shown in Figure 6). The silver wire does not fall off under the action of ultrasound, and the square resistance of the silver wire is 1Ω/sq. The local SEM image of the prepared fine circuit is shown in Fig. 7 .

3. Preparation of grid-shaped metal copper wire transparent conductive film

(1) Design the width and spacing of grid metal lines according to the requirements of light transmittance and resistivity, and make polydimethylsiloxane (PDMS) patterned templates according to the width and spacing of metal lines, so that the width and spacing of the template recesses The spacing is the same as that of the metal lines;

(2) Ultrasonicate a transparent PET film with a thickness of 50 μm in acetone, then wash it with deionized water, and dry it;

(3) Prepare Tris-hydrochloric acid activation solution, pH = 8.5, add dopamine hydrochloride, Tris concentration 1.2mg/mL, dopamine hydrochloride concentration 2mg/mL, put into cleaned PET, reaction temperature 15°C, reaction time 0.5h , take out the PET, rinse with deionized water, and dry;

(4) Contact the PDMS patterned template with the imprinting glue and dry it;

(5) Place the PDMS patterned template on the PET film treated in step 3), apply a pressure of 4kg and a temperature of 60°C, remove the template, and leave the embossed glue pattern on the PET film;

(6) Prepare a metal plating solution, the concentration of copper chloride (CuCl ₂ ) is 0.2%, add ethylenediaminetetraacetic acid (EDTA), boric acid (H ₃ BO ₃ ), sodium hydroxide (NaOH), and adjust the pH to 8- 9. Then add dimethylamine borane (DMAB) according to 3 times the molar number of copper chloride;

(7) Immerse the patterned PET in the metal plating solution, stir, take it out after 20 minutes, and rinse with deionized water;

(8) Wash with acetone to remove the embossing glue.

Due to the unique adhesion and reducibility of dopamine substances, the metal is only formed on the exposed parts of dopamine substances, so as to realize the selective deposition of metals on the substrate surface, and there is no need for additional sensitization or seed layer generation during electroless plating, and the process is simple and time-consuming. , friendly to the environment, and the metal layer adheres firmly to the substrate. In addition, since dopamine can be deposited on the surface of various materials under very mild conditions, it is suitable for various substrates, and the whole process is carried out at room temperature. Moreover, since a reducing agent is added to the metal plating solution, the continuity and conductivity of the metal film are ensured during electroless metal plating. In addition, since the thickness of metal wires can be adjusted from nanometers to micrometers, it can not only meet the needs of improving the surface roughness of conductive films, but also meet the requirements of fine conductive lines with a certain thickness.

That is to say, this embodiment has the following advantages:

1) High selectivity: metals are only deposited where dopamine exists;

2) Wide adaptability: dopamine substances can not only deposit and adhere on hard inorganic substrates such as metal and glass, but also be loaded on substrates such as semiconductors and polymers;

3) There is a layer of dopamine substances with excellent adhesion properties between the coating and the substrate, the binding force is better than the general method, and the metal coating does not fall off under ultrasonic conditions;

4) All processes can be carried out at room temperature, and the time is short;

5) The thickness of the coating can be adjusted from nanometers to micrometers, and the sheet resistance is small;

6) After the film is bent, the film resistivity changes little;

7) It is possible to make circuits on both sides of the substrate at the same time;

8) The reductive and adhesive properties of dopamine substances make it possible to electroplate the metal layer without reactivation on the surface, and the metal layer is dense and uniform in thickness;

9) Diversity and flexibility of patterning methods: patterning can be realized by various methods such as photolithography and printing;

10) The whole process does not require large instruments and equipment.

Moreover, since the substrate in this embodiment can be a transparent, translucent or opaque flexible or hard substance. Therefore, it can be applied to the preparation of metal grid transparent conductive films and fine lines, so as to be used in solar energy, OLED, display, optical devices, packaging, IC manufacturing, PCB manufacturing and other industries.

The second embodiment of the present invention relates to a method for preparing a patterned metal circuit. The second embodiment is roughly the same as the first embodiment, the main difference is that in the first embodiment, firstly, a layer of dopamine substance is modified on the substrate, and then the surface of the substrate is patterned by photolithography and other techniques, and then The patterned substrate is placed in a metal plating solution, adding a reducing agent, etc., so that a layer of metal is selectively deposited on the exposed place of dopamine, and finally the photoresist is removed. In the second embodiment of the present invention, a pattern is formed on the substrate by techniques such as photolithography, and then a layer of dopamine substances is deposited, and then the photoresist is removed to leave the pattern of dopamine substances, which is then immersed in metal plating. In the solution, a reducing agent is added to deposit a layer of metal where dopamine exists.

Specifically, as shown in FIG. 8 , step 801 is similar to step 101 and will not be repeated here.

In step 802, the substrate is activated after photolithographic patterning, that is, the patterned dopamine-based substrate surface is prepared on the substrate in the following manner:

First, photolithography is performed on the side of the substrate to be patterned to form a desired pattern. For example, if a double-sided pattern needs to be formed, the material to be patterned is patterned on both sides of the substrate by photolithography, placed in the activation solution for a period of time, and then taken out. Similar to the first embodiment, the photolithography technology includes any of the following photolithography technologies: ultraviolet lithography, extreme ultraviolet lithography, electron beam lithography, ion beam lithography, X-ray lithography and imprint lithography; wherein, Imprint lithography includes thermal imprinting, UV-curable nanoimprinting, and microcontact printing. Those skilled in the art can understand that microcontact printing can directly print the substance coated on it on the substrate similar to a stamp, which is more concise than the traditional one, and the minimum line width obtained is smaller, especially suitable for applications below a few hundred nanometers. , a scene invisible to the naked eye.

Next, the substrate is placed in an activation solution, the activation solution is similar to the first embodiment, and will not be repeated here.

Then, after the substrate is taken out from the activation solution, the photoresist formed in the photolithography process is removed to obtain the surface of the patterned dopamine-based substrate.

Of course, if the patterned conductive film to be prepared is a single-sided patterned conductive film, it is also possible to coat one side of the substrate with a barrier layer that cannot react with metals and then prepare the patterned dopamine-based substrate surface on the other side of the substrate. , such as coating a barrier layer on one side of the substrate, patterning the material to be patterned on the other side by photolithography, placing it in the activation solution for a period of time, and taking it out; or, in the step of placing the patterned substrate in the metal plating solution Before, the unpatterned side of the substrate is coated with a barrier layer.

In step 803, the patterned substrate is placed in a metal plating solution, and a layer of metal is deposited on the exposed dopamine-like substances on the surface of the substrate. This step is similar to step 103 and will not be repeated here.

The third embodiment of the present invention relates to a method for preparing a patterned metal circuit. The third embodiment is roughly the same as the first or second embodiment, the main difference is that: in the first or second embodiment, the patterned dopamine-based substrate surface is prepared on the substrate by photolithography; In an embodiment, a patterned dopamine-based substrate surface is prepared on the substrate by printing technology.

For example, after modifying a layer of dopamine substances on the substrate, the surface of the substrate is patterned by printing technology, and then the patterned substrate is placed in the metal plating solution, and a reducing agent is added to make the dopamine substances exposed. A layer of metal is selectively deposited, and finally the material used for printing is removed. Alternatively, a pattern is formed on the substrate by printing technology, and then a layer of dopamine is deposited, and then the material used for printing is removed to leave a pattern of dopamine, which is then also immersed in the metal plating solution, adding a reducing agent, and the dopamine A layer of metal is deposited where the like substance is present.

In this embodiment, printing methods include printing, screen printing, inkjet printing, letterpress printing, gravure printing, offset printing, thermal transfer printing, electrostatic copying, roll-to-roll printing, etc., and the materials that can be used for printing are various inks , photoresist, imprinting glue, polymer solutions such as polyesters, polyacrylics, polyamides, etc.

The following is an example of the preparation of grid-shaped metal copper wire transparent conductive film by printing:

(1) Ultrasonicate a transparent PET film with a thickness of 50 μm in acetone, wash it with deionized water, and dry it;

(2) Prepare Tris-hydrochloric acid activation solution, pH=8.5, add dopamine hydrochloride, Tris concentration 1.2mg/mL, dopamine hydrochloride concentration 2mg/mL, put into washed PET, reaction temperature 15°C, reaction time 0.5h , take out the PET, rinse with deionized water, and dry;

(3) Print the acetone solution of novolac resin on the PET substrate treated in step (2) by inkjet printing, and the printed pattern is designed according to the light transmittance and conductivity requirements of the film;

(4) Prepare a metal plating solution, the concentration of copper chloride (CuCl ₂ ) is 0.2%, add ethylenediaminetetraacetic acid (EDTA), boric acid (H ₃ BO ₃ ), sodium hydroxide (NaOH), and adjust the pH to 8- 9. Then add dimethylamine borane (DMAB) according to 3 times the molar number of copper chloride;

(5) Immerse the patterned PET in the metal plating solution, stir, take it out after 20 minutes, and rinse with deionized water;

(6) Wash with acetone to remove phenolic resin.

It is not difficult to find that this embodiment can also achieve the technical effects of the first or second embodiment, such as no additional sensitization or seed layer generation during electroless plating, the process is simple and time-consuming, environmentally friendly, and the metal layer adheres to the substrate. The attachment is firm, and the thickness of the metal layer is uniform, etc., which will not be repeated here.

The division of steps in the above methods is only for the sake of clarity of description. During implementation, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they contain the same logical relationship, they are all within the scope of protection of this patent. ; Adding insignificant modifications or introducing insignificant designs to the algorithm or process, but not changing the core design of the algorithm and process are all within the scope of protection of this patent.

Those of ordinary skill in the art can understand that the above-mentioned embodiments are specific examples for realizing the present invention, and in practical applications, various changes can be made to it in form and details without departing from the spirit and spirit of the present invention. scope.

Claims (17)

1. A method for preparing a patterned metal circuit, comprising the following steps: provide a base; Prepare a patterned dopamine substrate surface on the substrate by using the prepared activation solution and photolithography or printing technology; wherein, dopamine substances are added to the activation solution; The patterned substrate is placed in a metal plating solution, and a layer of metal is deposited on the exposed dopamine substance on the surface of the substrate; a reducing agent is added to the metal plating solution; The patterned metal circuit is a patterned conductive film or a fine circuit; Wherein, if the patterned conductive film to be prepared is a single-sided patterned conductive film, in the step of preparing the surface of the patterned dopamine-based substrate on the substrate, a barrier layer that cannot react with metals is coated on one side of the substrate. Then prepare the surface of the patterned dopamine-based substrate on the other side of the substrate; or, before the step of placing the patterned substrate in a metal plating solution, coat the non-patterned side of the substrate with the barrier layer. 2. The method for preparing a patterned metal circuit according to claim 1, wherein the reducing agent is one of the following or a mixture of any combination thereof: Glucose, formaldehyde, tartaric acid, potassium sodium tartrate, dimethylaminoborane, sodium borohydride, hydrazine dihydrochloride, hydrazine sulfate, hydrazine, sodium hypophosphite, glyoxylic acid, malic acid, sodium hypophosphite, citric acid, Sodium citrate, ascorbic acid, N,N-dimethylformamide, ethylene glycol, glutaraldehyde. 3. The method for preparing a patterned metal circuit according to claim 1, characterized in that, in the step of preparing a patterned dopamine-based substrate surface on the substrate using the prepared activation solution and photolithography or printing technology , with the following substeps: placing the substrate in the activation solution; After taking out the substrate from the activation solution, photolithography or printing is performed on the substrate on one side to be patterned to obtain the surface of the patterned dopamine-based substrate; After the step of placing the patterned substrate in the metal plating solution, the following steps are also performed: Substances used in photolithography or printing during said photolithography or printing process are removed. 4. The method for preparing a patterned metal circuit according to claim 3, wherein the substance used for photolithography or printing comprises: Photoresists, embossing adhesives, inks, substances that do not react with metals. 5. The method for preparing a patterned metal circuit according to claim 1, characterized in that, in the step of preparing a patterned dopamine substrate surface on the substrate using the prepared activation solution and photolithography or printing technology , with the following substeps: performing photolithography or printing on the side of the substrate to be patterned to form the desired pattern; placing the substrate in the activation solution; After the substrate is taken out from the activation solution, the substances used in the photolithography or printing process are removed to obtain the surface of the patterned dopamine-based substrate. 6. The method for preparing a patterned metal circuit according to any one of claims 3 to 5, characterized in that, When the substrate is placed in the activation solution, the activation solution is exposed to air, or oxygen is passed into the activation solution, or an oxidizing substance is added to the activation solution. 7. The method for preparing a patterned metal circuit according to any one of claims 3 to 5, characterized in that, The time for the substrate to be placed in the activation solution is from 1 second to 100 hours; The reaction temperature when the substrate is placed in the activation solution is less than 100°C. 8. The preparation method of patterned metal circuit according to claim 1, characterized in that, the pH buffer substance in the activation solution is sodium dihydrogen phosphate-citric acid buffer, disodium hydrogen phosphate-sodium dihydrogen phosphate buffer solution, barbiturate sodium hydrochloride buffer, Tris-hydrochloride buffer, sodium carbonate-sodium bicarbonate buffer. 9. The preparation method of patterned metal circuit according to claim 1, is characterized in that, The pH range of the activation solution is 2-11. 10. The method for preparing a patterned metal circuit according to claim 1, wherein the dopamine substance is a dopamine substance of any of the following structural formulas, or a polymer of dopamine substances of any of the following structural formulas, Ligand, acid salt or basic salt:

Wherein, R is an alkyl or substituted alkyl, R is _H , an alkyl or a substituted alkyl, R is _H , an alkyl or a substituted alkyl. 11. The method for preparing a patterned metal circuit according to claim 1, wherein the metal plating solution is a commercial metal plating solution, or the metal plating solution consists of the following components: Metal salts, solvent water, reducing agents, additives; Wherein, the metal salt is copper salt or silver salt. 12. The method for preparing a patterned metal circuit according to claim 11, characterized in that, The silver salt is one of the following or a mixture of any combination thereof: Silver nitrate, silver perchlorate, silver sodium cyanide, silver potassium cyanide, silver tetrafluoroborate, silver acetate, silver sulfate, silver bromide, silver chloride, silver oxide, silver carbonate, silver phosphate; The copper salt is one of the following or a mixture of any combination thereof: Copper sulfate, copper chloride, copper nitrate, copper acetate, copper carbonate and its hydrate, copper hydroxide, cuprous oxide, copper oxide. 13. The method for preparing a patterned metal circuit according to claim 11, characterized in that, The additive is one of the following or a mixture of any combination thereof: Ethanol, Methanol, Disodium EDTA, Ethylenediamine, Triethanolamine, EDTA, Thiourea, Bipyridyl, Polyethylene Glycol, Polyvinyl Alcohol, Polypyrrolidone, Sodium Lauryl Sulfate, Sodium citrate, sodium acetate, sodium pyrophosphate, potassium ferrocyanide, lead sulfate, ammonium sulfate, nickel sulfate, lactic acid, succinic acid, citric acid, propionic acid, glycolic acid, boric acid, tartrate, sodium hydroxide, Potassium hydroxide, ammonia water. 14. The method for preparing a patterned metal circuit according to claim 1, wherein the photolithography technique comprises any one of the following photolithography techniques: Ultraviolet lithography, extreme ultraviolet lithography, electron beam lithography, ion beam lithography, X-ray lithography and imprint lithography; The imprint lithography includes thermal embossing, UV-cured nanoimprinting and microcontact printing; The printing techniques include: Printing, screen printing, inkjet printing, letterpress printing, gravure printing, offset printing, thermal transfer printing, xerographic copying, roll-to-roll printing. 15. The method for preparing a patterned metal circuit according to claim 1, further comprising the following steps: Before preparing the surface of the patterned dopamine substrate on the substrate using the prepared activation solution and photolithography or printing technology, The pattern to be formed on the substrate is set according to the requirements of light transmittance and electrical conductivity. 16. The method for preparing a patterned metal circuit according to claim 15, characterized in that, The pattern to be formed on the substrate is composed of intersecting or non-intersecting straight lines, curves or folded lines. 17. The method for preparing a patterned metal circuit according to claim 1, characterized in that, The base is a transparent, translucent or opaque flexible or hard substance.

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