TW201736528A - Conductive paste - Google Patents

Abstract

The present invention relates to a conductive paste comprising 30 to 97% by weight of conductive particles, 3 to 70% by weight of an organic medium, and 0 to 20% by weight of a glass frit, wherein the organic medium comprises, by weight of the organic medium, 0.1 to 50% polar solvent. This polar solvent showed partial phase separation in a mixture of 0.1 to 90% by weight of the polar solvent, 0 to 89.9% by weight of butyl carbitol acetate and 10% by weight of tetradecane. The invention further relates to the use of the conductive paste and a method of producing an electrode on a semiconductor substrate.

Description

Conductive paste

The present invention relates to a conductive paste comprising 30 to 97% by weight of conductive particles, 3 to 70% by weight of an organic medium, and 0 to 20% by weight of a glass frit.

The conductive paste or ink can be used to form electrodes (such as conductive grid lines, such as silver grid lines) and bus bars on the surface of the semiconductor substrate or the insulating material substrate. It is particularly useful to print electrodes on a semiconductor substrate to be used in the production of solar cells or photovoltaic cells. When photons from sunlight excite the electrons from the semiconductor to the conduction band, the solar cells or photovoltaic cells Convert solar energy into electricity. The metal electrode contacting the semiconductor collects electrons flowing to the conduction band.

In addition to printing electrodes on a semiconductor substrate for use in the production of solar cells or photovoltaic cells, conductive paste or ink can also be used to print grid lines on an insulating substrate for use in producing printed electronic circuit boards or hybrid circuits on ceramic substrates.

In order to print fine lines onto a semiconductor substrate or an insulating substrate, a screen printing method is generally used for cost-effective mass production. However, producing uniform narrow lines and wireless interruptions are challenging for screen printing, especially for high speed screen printing. Industry printing speed depends on application requirements. It is in the range of 80 mm/s to 800 mm/s, preferably not slower than 150 mm/s, for example in solar cell printing, printing speeds are from 150 mm/s to 300 mm/s.

When a conductive paste is used for printing on a semiconductor substrate, the paste typically comprises conductive particles, typically a metal powder, an organic medium, and optionally a glass frit. The organic medium typically comprises at least one organic liquid, such as an organic or organic salt or other organic compound having a liquid form at room temperature. The organic medium optionally contains a polymeric component. To form a metal joint, a conductive paste is printed onto the substrate. Depending on the type of material, the substrate is subsequently heated at a temperature ranging from about 150 ° C to about 950 ° C, wherein the organic medium decomposes and the inorganic material forms conductive tracks and electrical contacts for the substrate.

Such conductive pastes are disclosed, for example, in CN-A 102831951, CN-A 102592710, CN-A 104078097, WO-A 2006/116376, CN-B 102831951 or US 6,787,342.

However, in order to be used in the screen printing method, the paste must be released in a quantitative manner from the surface of the material from which the screen is made and completely transferred to the surface of the substrate. On the other hand, the paste must exhibit sufficient adhesion to the surface of the substrate printed by the paste to obtain a thin line of sufficient thickness without any interruption.

Accordingly, it is an object of the present invention to provide a conductive paste which can be printed by screen printing without being adhered to the screen material in an excessively strong manner and which has sufficient adhesion to form fine grid lines without leakage. On the substrate printed on the paste.

This object is achieved by a conductive paste comprising: 30 to 97% by weight of conductive particles, 3 to 70% by weight of an organic medium and 0 to 20% by weight of a glass frit, wherein the organic medium comprises, by weight of the organic medium, 0.1 to 50% polar solvent. This polar solvent showed partial phase separation in a mixture of 0.1 to 90% by weight of the polar solvent, 0 to 89.9% by weight of butyl carbitol acetate and 10% by weight of tetradecane.

Surprisingly, it has been found that the paste is released from the screen material in a sufficient amount and adhered to the substrate for forming fine grid lines without leakage and interruption, the paste comprising an organic medium having a polar solvent, The polar solvent showed partial phase separation in a mixture of 0.1 to 90% by weight of a polar solvent, 0 to 89.9% by weight of butyl carbitol acetate and 10% by weight of tetradecane.

In the context of the present invention, a partial phase separation in a mixture of 0.1 to 90% by weight of a polar solvent, 0 to 89.9% by weight of butyl carbitol acetate and 10% by weight of tetradecane defines only a polar solvent. Butyl carbitol acetate or tetradecane is not necessarily present in the conductive ink.

In the present application, phase separation describes the partial spatial separation of the two liquids produced in a mixture of these two liquids at 25 ° C and ambient pressure due to the partial immiscibility of the two liquids.

Partial phase separation is macroscopically visible by forming an interface between two spatially separated phases, which can be characterized by abrupt changes in physical properties, including density, refractive index, color, viscosity, or turbidity. Phase separation can occur via the formation of an emulsion without an macroscopically visible interface. The emulsions can be either stable or become part of the phase separated system over time due to the difference in density between the continuous phase and the emulsion droplets. In a phase separation mixture of immiscible liquids, the phase having the lower density component is above the phase having the higher density component.

The miscibility of the two liquids is achieved by forming a Gibb's enthalpy of mixing ΔG in kJ/mol. Following the thermodynamic theory, ΔG is defined by: △G=△H-T△S, Since ΔH is a mixed enthalpy in kJ/mol, T is the temperature in Kelvin, and ΔS is the mixed entropy in kJ/(K mol). Therefore, the mixture of the two liquids showing negative ΔH and positive ΔS is completely miscible, which does not cause phase separation.

Because of the chemical equilibrium, immiscibility or phase separation is not complete. Those skilled in the art will use their equilibrium constant K to describe the chemical equilibrium. Following the thermodynamic theory, the Gibbs mixed free 焓 ΔG is related to the chemical equilibrium constant by ΔG = -RT ln(K), since R is the general gas constant, T is the temperature, and ln(K) is the equilibrium. The natural logarithm of the constant. This equation describes the impossibility of complete phase separation of two immiscible liquids.

In practice, it comprises 10 g of tetradecane, 0 to 90 g of butyl carbitol acetate and 0 to 90 g of propyl carbonate, butyl carbonate, DBE4, DBE5, triacetin or tripropionate. A mixture of polar solvents can result in the formation of an interface having a separate upper phase containing less than 10 g of tetradecane, while the remaining tetradecane is still soluble in tetradecane, butyl carbitol acetate and the polarity The second lower separated phase of the solvent. The mass of the remaining tetradecane which is not present in the upper phase depends on the equilibrium constant K and the respective Gibbs mixing free enthalpy of the respective solvent mixture. Because the other solvent has a higher density, the upper phase mainly contains tetradecane.

A stencil for screen printing is made by covering a selected area of the mesh of the stainless steel wire with a polymer layer called a stencil emulsion. During the screen printing process, the paste can only flow through the area of the stencil that is not covered by the stencil emulsion. For this reason, the stencil printing paste must exhibit a minimum adhesion that adheres to the surface of the stainless steel wire and adheres to the surface of the stencil emulsion.

Those skilled in the art will recognize that the adhesion between the surface of the paste and the material of the screen material is governed by the attraction and dispersion between the surface of the paste and the surface of the screen material. Paste surface and stencil These attractive dispersing forces between the materials can be reduced in such a way that the paste contains a non-polar solvent such as an aliphatic solvent or a fluorinated hydrocarbon and a polar solvent. Polar solvents and non-polar solvents show limited miscibility. Because of the limited miscibility, there is a thickening of the liquid solvent on the surface of the paste. The phase separation liquid forms a lubricating layer on the surface of the paste and reduces the adhesion between the surface of the paste and the surface of other materials. With this lubricating layer, the adhesion of the paste to the stencil will be reduced.

In a preferred embodiment of the invention, the organic medium has a boiling point of at least 230 °C. The higher the boiling point of the solvent, the lower the vapor pressure of the solvent at room temperature. Solvents having a boiling point below 230 ° C show an excessively high vapor pressure at room temperature and thus cause the paste to dry too quickly during the screen printing process. Paste drying during the screen printing process increases paste viscosity, resulting in line breaks due to limited paste flow during fine line screen printing.

In one embodiment of the invention, the organic medium additionally comprises at least one second organic compound that is immiscible with the polar solvent. The second organic compound is preferably selected from the group consisting of hydrocarbon-based lubricating oils, fluorinated components, fatty acid esters, hexanoic acid esters, octanoic acid esters, phthalic acid esters, undecanoic acid esters, and mixtures thereof.

Hydrocarbon-based lubricating oils suitable for use in the present invention include all common mineral oil base stocks. This will include oils with a chemical structure of naphthenic, paraffinic or aromatic. The naphthenic oil is composed of a methylene group arranged in a cyclic structure to which paraffin side chains are attached. The pour point is usually lower than the pour point of paraffin oil. Paraffinic oils contain saturated, linear or branched hydrocarbons.

High molecular weight linear paraffin lifts the pour point of the oil and is often removed by dewaxing. The aromatic oil is a closed carbocyclic hydrocarbon of a semi-unsaturated character and may have attached side chains. This oil is more susceptible to degradation than paraffin and naphthenic oils, resulting in corrosive by-products.

In fact, the base material will usually contain all three types that contain a certain proportion. Chemical composition of (paraffin, naphthenic and aromatic). For a discussion of the types of base stocks, see, for example, "A. Schilling, Motor Oils and Engine Lubricating, Scientific Publications, 1968, Sections 2.2 through 2.5".

Preferably, the second organic compound also has a boiling point of at least 230 °C.

According to the invention, the composition contains from 0.1 to 50% by weight of a polar solvent in a polar solvent of from 0.1 to 90% by weight, from 0 to 89.9% by weight of butyl carbitol acetate and from 10% by weight of fourteen Partial phase separation is shown in the mixture of alkanes. Preferably, the amount of the polar solvent is in the range of 0.5 to 30% by weight, and particularly preferably in an amount of 1 to 20% by weight.

In one embodiment of the invention, the polar solvent is selected from the group consisting of carbonates, glycerides, alcohols, and mixtures thereof.

If a carbonate is used as the polar solvent, the carbonate is preferably selected from the group consisting of propyl carbonate, butyl carbonate or a mixture thereof. If glyceride is used as a polar solvent on the other hand, the glyceride is selected from the group consisting of triacetin, tripropionate or a mixture thereof.

If the alcohol is used as a polar solvent, the alcohol is preferably selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol or a mixture thereof.

The conductive particles present in the conductive paste may be particles of any geometric shape composed of any conductive material. Preferably, the conductive particles comprise carbon, silver, gold, aluminum, platinum, palladium, tin, nickel, cadmium, gallium, indium, copper, zinc, iron, lanthanum, cobalt, manganese, molybdenum, chromium, vanadium, titanium, tungsten. Or a mixture or alloy thereof, or in the form of its core-shell structure. Preferred materials for the conductive particles are silver or aluminum, especially silver (due to its good electrical conductivity and good oxidation resistance).

The average particle size of the conductive particles is preferably in the range of 10 nm to 100 μm. More preferably, the average particle size ranges from 100 nm to 50 μm, and more preferably, the average particle size is between 500 From nm to 10 μm. The electrically conductive particles can be of any desired form known to those skilled in the art. For example, the particles can be in the form of flakes, rods, strands, clumps, spheres, or any mixture thereof. Spherical particles in the context of the present invention also comprise particles having an actual form that deviates from the ideal spherical form. For example, spherical particles may also have a droplet shape or be truncated for production reasons. Suitable particles which can be used to produce conductive pastes are known to those skilled in the art and are commercially available. More preferably, spherical silver particles are used. The advantage of spherical particles over their irregularly shaped particles is their improved rheological behavior.

The proportion of the conductive particles in the composition is in the range of 30 to 97% by weight. The ratio is preferably in the range of from 70 to 95% by weight, and particularly preferably in the range of from 85 to 92% by weight. This solid particle weight percentage is often referred to as the solids content.

The shape and size of the particles do not alter the nature of the invention. Particles can be used as a mixture of different shapes and sizes. It is known to those skilled in the art that when particles having a mixture of different shapes or sizes are dispersed in the same organic medium, they can result in higher or lower viscosities. In this case, it is known to those skilled in the art that the organic medium needs to be adjusted accordingly. Adjustments can be, but are not limited to, varying the solids content, solvent content, polymer content, thixotropic gum content, and/or surfactant content. For example, typically when nano-sized particles are used in place of micron-sized particles, the solids content must be reduced to avoid an increase in paste viscosity, which results in higher levels of organic components.

The conductive particles are typically coated with an organic additive during the production process (especially when it is composed of a metal). In the preparation of the composition for printing conductor tracks, the organic additives on the surface are typically not removed, so that they are subsequently also present in the conductive paste. The proportion of the additive for stabilization is usually not more than 10% by weight, based on the mass of the particles. Additive for coating conductive particles It can be, for example, a fatty amine or a fatty guanamine such as dodecylamine. Other additives suitable for stabilizing the particles are, for example, octylamine, decylamine and polyethylenediamine. Another specific example may be an epoxidized or non-epoxidized fatty acid, a fatty acid ester such as dodecanoic acid, palmitic acid, oleic acid, stearic acid or a salt thereof. The coating on the particles does not alter the properties of the invention.

In one embodiment, the conductive paste additionally comprises a frit. If a frit is present in the paste, any frit based on the lead-containing composition or the lead-free composition known to the skilled person can be used. The frit is not bound by any particular shape or form. The particles of the glass frit used have an average particle size ranging from 10 nm to 100 μm. The average particle size of the glass frit particles is more preferably in the range of from 100 nm to 50 μm, and particularly preferably in the range of from 500 nm to 10 μm. The particles used may be in any desired form known to those skilled in the art. For example, the particles can be in the form of flakes, rods, strands, clumps, spheres, or any mixture thereof. Spherical particles in this context mean that the actual form of the particles deviates from the ideal spherical form, for example, the spherical particles may also have a droplet shape or be truncated for production reasons. Suitable particles for use as frit are known to those skilled in the art and are commercially available. More preferably, spherical particles are used. The advantage of spherical particles over their irregularly shaped particles is their improved rheological behavior. According to the invention, the frit content is in the range of from 0 to 20% by weight, preferably from 0 to 10% by weight and most preferably from 1 to 5% by weight, based on the total mass of the conductive paste.

The organic medium in the conductive paste may additionally comprise at least one solvent. In one embodiment of the invention, the solvent comprises one or more solvents selected from the group consisting of liquid organic components having at least one oxygen atom. The liquid organic component having at least one oxygen atom is selected from the group consisting of alcohols, ester alcohols, glycols, glycol ethers, ketones, fatty acid esters or anthraquinone derivatives, excluding dibasic esters. The liquid organic component can be, for example, benzyl alcohol, Texanol ester alcohol, ethyl lactate, diethylene glycol monoethyl acetate, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, diethylene glycol monobutyl Ether acetate, butyl 赛路苏, butyl race road Subacetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl propionate, diethyl ether propionate, dimethylamino formaldehyde, methyl ethyl Ketone, γ-butyrolactone, ethyl linoleate, ethyl linoleic acid ethyl ester, ethyl myristate, ethyl oleate, methyl myristate, methyl linoleate, methyl linolenate Methyl oleate, dibutyl phthalate, dioctyl phthalate and terpineol.

The solvent as the liquid organic component having at least one oxygen atom can be used as a single solvent or a solvent mixture in the conductive paste. If a solvent mixture is used, the solvent may additionally comprise from 5 to 50% by weight, based on the total mass of the solvent mixture, of at least one dibasic ester. The dibasic ester is preferably selected from the group consisting of adipic acid, glutaric acid, dimethyl succinate or mixtures thereof.

When a single solvent or solvent mixture is used, it is essential that the organic binder can be dissolved in the selected single solvent or mixed solvent in an amount greater than 2% by weight, so that the organic medium contains at least 2% by weight of dissolved binder, based on the total mass of the organic medium. Agent.

In one embodiment of the present invention, the paste additionally comprises 0.1 to 20% by weight of at least one additive selected from the group consisting of surfactants, thixotropic agents, plasticizers, solubilizers, defoamers, desiccants, and cross-linking agents. Linking agents, inhibitors, complexing agents and/or conductive polymer particles. The additives may be used singly or as a mixture of two or more thereof.

When a surfactant is used as an additive, it is possible to use only one surfactant or more than one surfactant. In principle, all surfactants known to those skilled in the art or as described in the prior art may be suitable. Preferred surfactants are single or multiple compounds such as anionic, cationic, amphoteric or nonionic surfactants. However, it is also possible to use polymers having pigment-related anchor groups which are known to the skilled person as surfactants.

If the conductive particles are pre-coated with a surfactant, the conductive paste may not contain an additional surfactant as an additive.

In addition to the solvent and other organic additives, the conductive paste may also contain an organic binder in the range of 0.1 to 20% by weight. The organic binder may be selected from natural or synthetic resins and polymers. The choices are based on, but not limited to, solvent compatibility and chemical stability, as is known to those skilled in the art. For example, common adhesives as disclosed in the prior art include: cellulose derivatives, acrylic resins, phenolic resins, urea-formaldehyde resins, alkyd resins, aliphatic petroleum resins, melamine formaldehyde resins, rosins, poly Ethylene, polypropylene, polystyrene, polyether, polyurethane, polyvinyl acetate and copolymers thereof.

The paste of the present invention is particularly useful in screen printing methods for producing conductive patterns on a substrate. More preferably, the paste is used to print electrodes on a semiconductor for use in the production of solar cells.

The present invention further relates to a method for producing an electrode on a semiconductor substrate, comprising the steps of: (a) printing a conductive pattern on a semiconductor substrate in a predetermined pattern in accordance with any one of items 1 through 11 of the patent application; Pasting to form a printed semiconductor substrate, (b) drying the printed semiconductor substrate at a temperature ranging from 100 ° C to 300 ° C, and (c) heating the dried printed semiconductor substrate having the printed composition to a dielectric substrate The sintering temperature is in the range of 650 ° C to 900 ° C to sinter the conductive particles.

Suitable semiconductor substrates are, for example, such substrates for producing photovoltaic cells, which include an n-type region, a p-type region, a p-n junction, and a conductive grid. The photovoltaic cell includes an anti-reflective layer on the surface of the substrate as appropriate. The semiconductor substrate may be a solid substrate coated with single crystal germanium, polycrystalline germanium, or amorphous germanium or a substrate coated with a surface of polycrystalline or amorphous transparent conductive oxide (TCO), Such as indium tin oxide (ITO); transparent conductive oxide based on ZnO, such as indium gallium zinc oxide (IGZO), indium zinc tin oxide (IZTO), indium zinc oxide (IZO), indium oxide tungsten (IWO) gallium zinc oxide ( GZO). The conductive grid lines are formed from a conductive paste by a screen printing method.

Screen printing in step (a) is carried out in any known manner known to the skilled person. The printing method is especially an industrial high speed screen printing method. In such methods, the printing speed depends on the application requirements. It is in the range of 80 mm/s to 800 mm/s, preferably not slower than 150 mm/s, for example in solar cell printing, printing speeds are from 150 mm/s to 300 mm/s.

After printing the conductive paste onto the semiconductor substrate, the printed semiconductor substrate is dried at a temperature ranging from 200 ° C to 300 ° C. The drying step is preferably carried out for a duration ranging from 10 to 50 seconds, particularly preferably from 15 to 30 seconds.

After drying, the dried printed semiconductor substrate is heated to a sintering temperature in the range of 700 ° C to 900 ° C to sinter the conductive particles. In the heating step, the printed semiconductor substrate is heated from the drying temperature to the sintering temperature in 5 to 50 seconds, preferably 5 to 35 seconds, maintaining the sintering temperature for less than 5 seconds, and then within 3 to 60 seconds, The printed semiconductor substrate is cooled to room temperature, preferably within 3 to 30 seconds. The entire heating step is carried out for a duration ranging from 10 to 80 seconds, preferably from 15 to 50 seconds.

Figures 1 to 3 show micrographs of the printed lines of Examples 1 to 3 after drying at 250 °C.

4 to 6 show microscope pictures of the printed lines of Examples 1 to 3 after sintering at 800 °C.

Example

The conductive paste according to the composition in Table 1 has been screen printed using the stencil parameters as shown in Table 3.

The content of triacetin has been increased by reducing the solvent blend containing butyl carbitol, butyl carbitol acetate, methyl oleate and an aliphatic solvent. MMA stands for methyl methacrylate. SMA stands for stearyl methacrylate.

The sliding of the paste has been measured using a commercially available rheometer using a plate-plate geometry.

The rotational speed of the upper plate is indicated in revolutions per minute (rpm). Shear stress is indicated by Pascal. During the application of constant shear stress, the rotational speed of the upper plate will depend on the viscosity of the paste. Higher paste viscosity will cause slower rotational speeds under constant shear stress. In the case where the adhesion between the paste and the stainless steel plate is weak, the wall slip effect can dominate the rotational speed under constant shear stress. The sliding effect can be produced by forming a thin layer of liquid solvent on the surface of the paste. More paste slip will cause a faster rotation speed under constant shear stress.

Screen printing has been done using the following stencil parameters:

The results of the printing method are shown in Figures 1 to 6.

Figures 1 to 3 show micrographs of the printed lines of Examples 1 to 3 after drying at 250 °C.

4 to 6 show microscope pictures of the printed lines of Examples 1 to 3 after sintering at 800 °C.

The amount of transferred paste is shown in Table 4. In this table, the paste transfer per unit describes the difference between the weight of the wafer before printing and the weight of the wafer after printing.

Among the compositions E1, E2 and E3, triacetin is the most polar solution Agent. The higher the content of triacetin, the stronger the phase separation effect, which results in the formation of a thin liquid layer on the surface of the paste. This thin liquid layer slides the paste during the adhesion measurement with the plate-plate geometry. The increased paste slip also allows more of the complete paste to be released from the surface of the stencil material. Therefore, the weight of the paste transferred from the screen to the substrate is increased as the triacetin content is increased. As can be further seen in the figures, increasing the amount of triacetin results in less leakage. 1 and 4 show the line of the embodiment E1, and Figs. 2 and 5 show the line printed with the conductive paste E2, and Figs. 3 and 6 show the line printed with the conductive paste E3.

Claims (16)

A conductive paste comprising: 30 to 97% by weight of conductive particles, 3 to 70% by weight of an organic medium, and 0 to 20% by weight of a glass frit, wherein the organic medium comprises 0.1 to 50 by weight of the organic medium % of a polar solvent, wherein the polar solvent exhibits partial phase separation in a mixture of 0.1 to 90% by weight of the polar solvent, 0 to 89.9% by weight of butyl carbitol acetate and 10% by weight of tetradecane. The conductive paste of claim 1, wherein the polar solvent has a boiling point of at least 230 °C. The conductive paste of claim 1, wherein the organic medium additionally comprises at least one second organic compound that is immiscible with the polar solvent. The conductive paste of claim 3, wherein the second organic compound is selected from the group consisting of hydrocarbon-based lubricating oils, fluorinated components, fatty acid esters, hexanoic acid esters, octanoic acid esters, decanoic acid esters. , undecanoic acid esters and mixtures thereof. The conductive paste of claim 3, wherein the second organic compound has a boiling point of at least 230 °C. The conductive paste of claim 1, wherein the polar solvent is selected from the group consisting of carbonates, glycerides, alcohols, and mixtures thereof. The conductive paste of claim 6, wherein the carbonate is selected from the group consisting of propylene carbonate, butyl carbonate or a mixture thereof. The conductive paste of claim 6, wherein the glyceride is selected from the group consisting of triacetin, tripropionate or a mixture thereof. The conductive paste of claim 6, wherein the alcohol is selected from the group consisting of: 1,3-propanediol, 1,4-butyl A diol, 1,5-pentanediol or a mixture thereof. The conductive paste of claim 1, wherein the conductive particles comprise carbon, silver, gold, aluminum, platinum, palladium, tin, nickel, cadmium, gallium, indium, copper, zinc, iron, lanthanum, cobalt, manganese , molybdenum, chromium, vanadium, titanium, tungsten or a mixture thereof or alloy thereof, or in the form of its core-shell structure. The conductive paste of claim 1, wherein the conductive particles are coated with an organic additive. The conductive paste of claim 1, wherein the electrode is printed on the semiconductor substrate by screen printing. A method for producing an electrode on a semiconductor substrate, the method comprising the steps of: (a) printing a conductive paste of any one of claims 1 to 11 in a predetermined pattern on a semiconductor substrate to Forming a printed semiconductor substrate, (b) drying the printed semiconductor substrate at a temperature ranging from 100 ° C to 300 ° C, and (c) heating the dried printed semiconductor substrate having the printed composition to A sintering temperature in the range of 650 ° C to 900 ° C is used to sinter the conductive particles. The method of claim 13, wherein the drying step is carried out for a duration ranging from 10 to 50 seconds. The method of claim 13, wherein in the heating step, the printed semiconductor substrate is heated from room temperature to the sintering temperature in 5 to 50 seconds, the sintering temperature is maintained for 1 to 5 seconds, and then The printed semiconductor substrate was cooled to room temperature in 3 to 60 seconds. The method of claim 13, wherein the semiconductor substrate is a semiconductor substrate for a solar cell.