KR20020036933A - Coated aluminium nitride with organo-surface treating agent for thermally conductive paste and its manufacturing method - Google Patents

Abstract

PURPOSE: Provided are an aluminum nitride for thermal conductive paste coated with organic surface-treating agent, and a method for coating of aluminum nitride. CONSTITUTION: The aluminum nitride for thermal conductive paste coated with organic surface-treating agent, is produced by coating a surface of aluminum nitride with organic surfacing preparations selected from the group consisting of alkyl alkenyloxy benzoic acid derivative(formula 1), alkenyloxy aralkyl fatty acid derivative(formula 2), ricinoleic acid derivative(formula 3), succinyl acid-substituted oleic acid derivative(formula 4), linolenic acid derivative(formula 5), trimellitic acid imide derivative(formula 6), alkenyloxy benzene dicarboxylic acid derivative(formula 7) and alkyl alkenyloxy phenol derivative(formula 8). In the formula 1, R1 and R2 represent hydrogen, alkyl and branched alkyl, alkenyl and branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl and hydroxyalkenyl having C1-C20. In the formula 2, R1 and R2 represent hydrogen, alkyl and branched alkyl, alkenyl and branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl and hydroxyalkenyl having C1-C20, and n is a natural number of 1-18. In the formula 3, R represents alkyl and alkenyl groups of C1-C17. In the formulas 4 and 5, R represents alkyl and alkenyl groups of C1-C18. In the formula 6, R represents alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, allyl, aryl and arylalkyl of C1-C20. In the formulas 7 and 8, R1 and R2 represent alkyl and branched alkyl, alkenyl and branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, alkoxyalkenyl, allyl, aryl and arylalkyl having C1-C20.

Description

Coating method of aluminum nitride and aluminum nitride coated with organic surface treatment agent {Coated aluminum nitride with organo-surface treating agent for thermally conductive paste and its manufacturing method}

The present invention relates to a coating method of aluminum nitride and aluminum nitride for thermal conductive paste coated with an organic surface treatment agent. More specifically, the present invention relates to a thermally conductive paste, an epoxy encapsulant, a thermally conductive coating tape, a printed circuit board, and the like for attaching aluminum nitride to an organic surface treatment agent and attaching a semiconductor chip on a die of a lead frame. It relates to a coating method of aluminum nitride and aluminum nitride for thermal conductive paste coated with an organic surface treatment agent, which may be included in the resin.

Aluminum nitride is a covalent compound in which a nitrogen atom and an aluminum atom are covalently bonded, and is a ceramic compound having excellent heat resistance, excellent mechanical strength, high thermal conductivity, high electrical insulation, and a thermal expansion coefficient similar to that of silicon. Is getting. In particular, in recent years, devices of microelectronics such as semiconductors require rapid heat dissipation as the degree of integration increases. Currently, when alumina is used as a semiconductor substrate, there is a limit in heat dissipation performance, and it is expected to use aluminum nitride having a high thermal conductivity of about 5 to 10 times that of alumina. In addition, conductive adhesives widely used in the electronics industry are known for various uses, but one of the most widely known is the use of semiconductor chips to attach to dies, substrates and other supports of leadframes. These die attach adhesives are mainly used as a mixture of various epoxy resins and proper properties of epoxy compounds having various chemical structures have been obtained to obtain required properties. Die attach adhesive is an adhesive that bonds a semiconductor chip onto a die of a lead frame. Currently, silver paste adhesive using silver powder is mainly used. In addition, silver powder is expensive in terms of price and high heat in an operation state due to the recent increase in semiconductor integration. There is a limit to the use of silver paste for heat dissipation. Therefore, there is a demand for a die attach adhesive having greatly improved thermal conductivity. The content of silver powder in the composition of silver paste has a great influence on the thermal conductivity. When using 50% by weight of aluminum nitride than when using 80% by weight of silver powder, the thermal conductivity can be more than doubled, and the thermal conductivity can be increased by increasing the content of silver powder. As the price increases, the price increases, as well as the rheological change required as a thermally conductive adhesive, the adhesion according to the increase in content, and the various required properties decrease. In particular, it is necessary to solve the rheological problems caused by a decrease in adhesion due to a decrease in resin content, a decrease in bonding strength between the silver powder and the matrix resin of the cured adhesive, and an increase in filler. In addition, the adhesive using silver powder is accompanied by an increase in electrical conductivity in addition to an increase in pure thermal conductivity after adhesion. This increase in electrical conductivity causes another problem in the die attach adhesive, and the situation is in need of improvement.

In a thermally conductive paste that uses aluminum nitride as a filler, aluminum nitride is a ceramic compound having excellent heat resistance and strength, but aluminum nitride itself is highly reactive and reacts with water to cause hydrolysis to cause ammonia Occurs, and the oxygen content increases. Since the increase of oxygen leads to the deterioration of the intrinsic properties of aluminum nitride, strict control is required in the manufacturing process and storage, and the water resistance needs to be improved to solve this problem. In order to solve this problem, an example of treating stearic acid as an organic surface treatment agent has been published, but the water resistance has been increased, but since the bond with the resin is not formed, the physical properties of the paste are lowered. Metals such as copper were used as fillers, but no improvement in physical properties as fillers has been published.

Degradation of the filler in the conductive paste leads to a deterioration of various properties inherent to the filler itself, resulting in breakage and detachment of the adhesive material. Therefore, it is necessary to improve the water resistance of aluminum nitride. In particular, moisture absorption of aluminum nitride in a high temperature, high humidity environment in a die attach adhesive may cause delamination or cracking of packaging and popcorn at the interface due to the generation of ammonia gas, which is a property of thermally conductive pastes. This causes a decrease. In particular, aluminum nitride as a filler in thermally conductive pastes needs to improve dispersibility in matrix resins by itself. When the dispersibility of a filler such as aluminum nitride in the matrix resin is low, separation between the resin and the filler, in particular, separation between the resin and the filler during curing of the matrix resin may occur, which is caused by a semiconductor chip by a thermally conductive paste. Not only may cause defects in the adhesion of the semiconductor, but even if the adhesion is made, there may be a problem that a non-uniform thermal conduction phenomenon occurs between the semiconductor chip and the die.

In particular, rheological properties such as thermally conductive pastes and epoxy encapsulants, conductive coating tapes, and resins for forming multilayers of printed circuit boards have a great impact on workability and productivity in the bonding process. Among these properties, the viscosity and thixotropic index are very important factors, and the dispersibility of the filler such as aluminum nitride into the matrix resin is involved in the flowability, spreadability, and tailing of the conductive paste.

In addition, when the content of the filler is increased in the thermally conductive paste, the bonding strength between the filler and the matrix resin is weakened, which causes a problem that is accompanied by a decrease in various mechanical properties.

Therefore, as a result of intensive studies to improve the water resistance, dispersibility, rheological properties, and binding properties of resin to aluminum nitride, various aliphatic groups including various hydrophobic groups and functional groups reacting with resins, The present invention has been completed by resolving the above problems by coating with an organic surface treatment agent such as an aromatic fatty acid, and improving water resistance, dispersibility, rheological properties, and bonding with resin. This surface treated aluminum nitride is mixed with an epoxy resin as a matrix resin to form a conductive adhesive. The conductive adhesive thus formed may be used in adhesives, epoxy encapsulants, conductive coating tapes, multilayered resins for printed circuit boards, and the like in the electronic industry including bonding semiconductor chips on dies of leadframes.

It is an object of the present invention to provide an aluminum nitride for thermally conductive paste coated with organic surface treatment agents such as various aliphatic and aromatic fatty acids including aluminum nitride with various hydrophobic groups and functional groups that react with resins.

Another object of the present invention is to provide a method for coating aluminum nitride for thermally conductive paste coated with organic surface treatment agents such as various aliphatic and aromatic fatty acids including aluminum nitride with functional groups that react with various hydrophobic groups and resins.

Aluminum nitride for thermal conductive paste coated with an organic surface treatment agent according to the present invention, the surface of the aluminum nitride is an alkyl alkenyloxy benzoic acid derivative (Formula 1), alkenyloxy aralkyl fatty acid derivative (Formula 2), ricinoleic acid Derivatives (Formula 3), succinylic acid substituted oleic acid derivatives (Formula 4), linolenic acid derivatives (Formula 5), trimellitic acid imide derivatives (Formula 6), alkenyloxy benzene dicarboxylic acid derivatives (Formula 7) and alkyl alkenyloxy It is made by coating with an organic surface treatment agent selected from the group consisting of phenol derivatives (Formula 8).

Wherein R ₁ and R ₂ are hydrogen, alkyl having 1 to 20 carbon atoms and branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl.

Wherein R ₁ and R ₂ are hydrogen, alkyl having 1 to 20 carbon atoms and branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, n is from 1 to 18 Is a natural number of.

R is an alkyl and alkenyl group having 1 to 17 carbon atoms.

R is an alkyl and alkenyl group having 1 to 18 carbon atoms.

R is an alkyl and alkenyl group having 1 to 18 carbon atoms.

Wherein R is alkyl having 1 to 20 carbon atoms, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, allyl, aryl, arylalkyl.

Wherein R ₁ and R ₂ are alkyl having 1 to 20 carbon atoms, branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, alkoxyalkenyl, allyl , Aryl, arylalkyl.

Wherein R ₁ and R ₂ are alkyl having 1 to 20 carbon atoms, branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, alkoxyalkenyl, allyl , Aryl, arylalkyl.

Coating method of the aluminum nitride for conductive paste coated with the organic surface treatment agent according to the present invention, (1) Alkyl alkenyloxy benzoic acid derivatives, alkenyloxy aralkyl fatty acid derivatives, ricinoleic acid derivatives based on 100 parts by weight of aluminum nitride 0.1-10 parts by weight of an organic surface treatment agent selected from the group consisting of succinylic acid substituted oleic acid derivatives, linolenic acid derivatives, trimellitic acid imide derivatives, alkenyloxy benzene dicarboxylic acid derivatives and alkyl alkenyloxy phenol derivatives A dissolution step of completely dissolving 100 to 500 parts by weight of a solvent to obtain a reaction mixture; (2) refluxing the reaction mixture at 80 ° C. for 2 to 4 hours; (3) a solvent removal step of cooling to room temperature after reflux and removing the organic solvent; (4) after the removal of the solvent, a heat treatment step of heat-treating the obtained powder in a vacuum oven at 120 to 160 ℃; comprising.

The aluminum nitride coated with the organic surface treating agent may be obtained by the coating method of the aluminum nitride for thermal conductive paste coated with the organic surface treating agent according to the present invention.

Hereinafter, the present invention will be described in detail with reference to specific examples.

Aluminum nitride for thermal conductive paste coated with an organic surface treatment agent according to the present invention, the surface of the aluminum nitride, alkyl alkenyloxy benzoic acid derivatives, alkenyloxy aralkyl fatty acid derivatives, ricinoleic acid derivatives, succinylic acid substituted oleic acid derivatives, Linolenic acid derivatives, trimellitic acid imide derivatives, alkenyloxy benzene dicarboxylic acid derivatives and alkyl alkenyloxy phenol derivatives, characterized in that the coating with an organic surface treatment agent selected from the group consisting of.

The organic surface treatment agents are coated on the surface of the aluminum nitride to improve the water resistance of the aluminum nitride, and exhibit dispersibility in the resin and reactivity with the resin, thereby providing good rheological properties, water resistance, and good mechanical strength such as adhesion and shear strength. Eggplant provides aluminum nitride powder.

The aluminum nitride has a layer in which a part of its surface is hydrolyzed in air and changed into a hydroxyl group, and the aluminum metal is mixed with an aluminum surface by mixing with an organic surface treatment agent having an acid as the fatty acid or a derivative thereof and appropriate heating (refluxing). It is believed that the esterification and the production of ether bonds take place. Thus, the degree of coating is proportional to the amount of hydroxyl groups on the surface of aluminum nitride and the adsorption capacity of the organic surface treatment agent to be coated. The hydroxyl groups formed on the aluminum nitride surface are weakly basic, and fatty acids and the like are usually acidic, so physical adsorption is advantageous on the surface of the aluminum nitride, and the surface organic protective coating film is formed together with the desorption of moisture at a high temperature. Aliphatic alcohols and aromatic alcohols can also be used as the protective organic layer, but the extent is lower than fatty acids. The amount to which the protective organic layer is coated is constant for aluminum nitride produced under uniform conditions.

In the present invention, the aluminum nitride for thermally conductive paste coated with the organic surface treating agent is mixed with the carboxylic acid derivatives and the phenol derivatives with the surface of the aluminum nitride as a surface-coated powder, preferably in the range of 30 to 80% by weight. 40 to 60% by weight is preferred. The aluminum nitride powder coated with the organic surface treatment agent has suitable physical properties as a die attach adhesive when mixed with an epoxy resin and used as a thermally conductive adhesive. As a result, a conductive paste having excellent dispersibility and water resistance without lowering the thermal conductivity can be prepared.

Coating method of the aluminum nitride for conductive paste coated with the organic surface treatment agent according to the present invention, (1) Alkyl alkenyloxy benzoic acid derivatives, alkenyloxy aralkyl fatty acid derivatives, ricinoleic acid derivatives based on 100 parts by weight of aluminum nitride 0.1-10 parts by weight of an organic surface treatment agent selected from the group consisting of succinylic acid substituted oleic acid derivatives, linolenic acid derivatives, trimellitic acid imide derivatives, alkenyloxy benzene dicarboxylic acid derivatives and alkyl alkenyloxy phenol derivatives A dissolution step of completely dissolving 100 to 500 parts by weight of a solvent to obtain a reaction mixture; (2) refluxing the reaction mixture at 80 ° C. for 2 to 4 hours; (3) a solvent removal step of cooling to room temperature after reflux and removing the organic solvent; (4) after removing the solvent, the powder obtained is heat-treated in a vacuum oven at 120 to 160 ℃; characterized in that it comprises a.

The dissolution step is a pretreatment step for allowing the organic surface treatment agent to react with hydroxyl groups on the surface of aluminum nitride by heating by reflux, and preparing a reaction mixture for the reaction. When the organic surface treatment agent is used in an amount less than 0.1 part by weight based on 100 parts by weight of the aluminum nitride, there may be a problem that the coating layer of aluminum nitride by the organic surface treatment agent is not formed sufficiently, on the contrary, exceeding 10 parts by weight Too much organic surface treating agent may be added, which may cause a problem that the unreacted organic surface treating agent lowers the physical properties of the paste. The organic solvent used in the dissolving step may be understood as a reaction medium for an effective reaction for causing the organic surface treatment agent to react on the surface of the aluminum nitride by a dehydration reaction by heating.

In the reflux step, the reaction mixture is refluxed at 80 ° C. for 2 to 4 hours to form a coating layer of an organic surface treatment agent on the surface of aluminum nitride by heating.

After refluxing, the reaction mixture is cooled to room temperature, the organic solvent is removed, and then, the obtained powder is subsequently heat treated at 120 to 160 ° C. so that a dehydration reaction occurs so that the coating layer of the organic surface treatment agent is closely attached to the aluminum nitride. .

The aluminum nitride coated with the organic surface treating agent may be obtained by the coating method of the aluminum nitride for thermal conductive paste coated with the organic surface treating agent according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described.

The following examples are intended to illustrate the invention and should not be understood as limiting the scope of the invention.

Experiment 1; Coating of Aluminum Nitride

Example 1

As shown in Table 1 below, 240 g of 3,4-diallyloxybenzoic acid and 10 kg of aluminum nitride were dissolved in 30 kg of benzene to prepare a reaction mixture, and the reaction mixture was refluxed at 80 ° C. for 3 hours. After 3 hours, the reaction mixture was cooled to room temperature and the slurry was filtered to remove benzene. Subsequently, the obtained aluminum nitride powder was heat-treated at 150 ° C. to obtain coated aluminum nitride.

Example 2

A coated aluminum nitride was obtained in the same manner as in Example 1 except that 280 g of 3- ( p -allyloxyphenyl) propionic acid was used.

Example 3

A coated aluminum nitride was obtained in the same manner as in Example 1, except that 230 g of ricinoleic acid was used.

Example 4

A coated aluminum nitride was obtained in the same manner as in Example 1, except that 230 g of succinyl-substituted oleic acid was used.

Example 5

A coated aluminum nitride was obtained in the same manner as in Example 1, except that 230 g of linolenic acid was used.

Example 6

A coated aluminum nitride was obtained in the same manner as in Example 1 except that 310 g of trimellitic acid was used.

Example 7

The coated aluminum nitride was obtained in the same manner as in Example 1, except that 210 g of 5-octadecyloxyphthalic acid was used.

Example 8

A coated aluminum nitride was obtained in the same manner as in Example 1, except that 280 g of nonylphenol was used.

Experiment 2; Preparation of Conductive Paste

Examples 9-16

The specimens were prepared by mixing in the ratio of the components shown in Table 2 below, and placed in a mold of 1 × 1 × 3 cm (horizontal × vertical xheight) for 10 minutes at 175 ° C. The physical properties of the prepared specimens were measured, and the results are shown in Table 3 below. Measurement of physical properties of the specimen is as follows.

Comparative Example 1

It was mixed in the ratio of the components shown in Table 2 and used aluminum nitride powder was not treated with an organic surface treatment agent.

Viscosity: with Model HBDV-II ^{+ from} Brookfield, measured at rpm 0.5 and 5

Ion Concentration: The paste was cured and then ground and filtered through a network between 60-100 mesh. 5 g of the sample was taken, placed in a flask, deionized water, and allowed to stand at 100 ° C. for 24 hours, followed by filtration, and then injected into ion chromatography (Dionex, DX-500) for analysis of cations and anions. The content of ionic impurities was calculated based on the chromatogram data obtained here.

Weight loss, weight loss (175 ° C. curing, 1 hour): TGA (Shimadzu TGA 50 Thermal Analyzer) was measured in a nitrogen atmosphere at a temperature increase rate of 10 ° C./min.

Glass transition temperature and curing time were measured at a rate of 10 ℃ / min Perkin-Elmer DSC 7 in a nitrogen atmosphere.

Tensile Shear Strength: Measured at a rate of 0.05 inch / min using UTM (Instron Model 4467).

Thermal expansion coefficient: Measured using a Universal V2.5H TMA from TA.

Moisture absorption: measured after 5 days at 80 ℃ using a constant temperature and humidity bath.

Thermal conductivity: A steady state measurement was used to heat the heater head with a constant heating value and to measure the temperature gradient in the specimen. Laser scintillation was used for calibration. Specimen used was 1 x 1 x 3 cm.

Comparative Example 2

A specimen was prepared in the same manner as in Example 9 except that the surface-treated aluminum nitride was used, and the physical property test results are shown in Table 3 above.

As shown in the results of the above examples and comparative examples, the paste composition prepared by using the aluminum nitride for thermal conductive paste coated with the organic surface treatment agent according to the present invention can adjust the viscosity according to the type of surface treatment agent, Low chlorine and sodium concentrations were shown. In addition, it was confirmed that the glass transition temperature was slightly high due to the combination of the matrix resin and the organic surface treatment agent, and the tensile shear strength was very large. In particular, the hygroscopicity showed lower water absorption than the untreated surface (Comparative Example).

Therefore, according to the present invention, aluminum nitride is coated with organic surface treatment agents such as various aliphatic and aromatic fatty acids including functional groups reacting with various hydrophobic groups and resins, and thus water resistance, dispersibility, rheological properties, and bonding to resins. It provides a surface-treated aluminum nitride with improved properties, such as aluminum nitride can be mixed with the epoxy resin as a matrix resin to form a conductive adhesive, and the conductive adhesive is formed to bond the semiconductor chip on the die of the lead frame There is an effect that can be used as an adhesive in the electronics industry, including.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (4)

The surface of aluminum nitride is alkyl alkenyloxy benzoic acid derivative (Formula 1), alkenyloxy aralkyl fatty acid derivative (Formula 2), ricinoleic acid derivative (Formula 3), succinylic acid substituted oleic acid derivative (Formula 4), linolenic acid derivative Coating with an organic surface treatment agent selected from the group consisting of (Formula 5), trimellitic acid imide derivatives (Formula 6), alkenyloxy benzene dicarboxylic acid derivatives (Formula 7) and alkyl alkenyloxy phenol derivatives (Formula 8) Aluminum nitride for thermally conductive paste coated with an organic surface treatment agent, characterized in that: Formula 1 Wherein R ₁ and R ₂ are hydrogen, alkyl having 1 to 20 carbon atoms and branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, Formula 2 Wherein R ₁ and R ₂ are hydrogen, alkyl having 1 to 20 carbon atoms and branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, n is from 1 to 18 Is a natural number of, Formula 3 Wherein R is an alkyl and alkenyl group having 1 to 17 carbon atoms, Formula 4 Wherein R is an alkyl and alkenyl group having 1 to 18 carbon atoms, Formula 5 Wherein R is an alkyl and alkenyl group having 1 to 18 carbon atoms, Formula 6 Wherein R is alkyl having 1 to 20 carbon atoms, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, allyl, aryl, arylalkyl, Formula 7 Wherein R ₁ and R ₂ are alkyl having 1 to 20 carbon atoms, branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, alkoxyalkenyl, allyl , Aryl, arylalkyl, Formula 8 Wherein R ₁ and R ₂ are alkyl having 1 to 20 carbon atoms, branched alkyl, alkenyl, branched alkenyl, cycloalkyl, cycloalkenyl, hydroxyalkyl, hydroxyalkenyl, alkoxyalkyl, alkoxyalkenyl, allyl , Aryl, arylalkyl. The method of claim 1, Aluminum nitride for conductive paste coated with an organic surface treatment agent, characterized in that the coating is made of two or more organic surface treatment agents selected from the group of organic surface treatment agents. The method of claim 1, The aluminum nitride for thermally conductive paste, characterized in that the organic surface treatment agent is coated in the range of 0.1 to 10% by weight relative to the aluminum nitride. (1) 100 parts by weight of aluminum nitride, alkyl alkenyloxy benzoic acid derivatives, alkenyloxy aralkyl fatty acid derivatives, ricinoleic acid derivatives, succinylic acid substituted oleic acid derivatives, linolenic acid derivatives, trimellitic acid imide derivatives, alkenyloxy A dissolution step of completely dissolving 0.1 to 10 parts by weight of an organic surface treatment agent selected from the group consisting of benzene dicarboxylic acid derivatives and alkyl alkenyloxy phenol epoxy derivatives to 100 to 500 parts by weight of an organic solvent such as benzene to obtain a reaction mixture; (2) refluxing the reaction mixture at 80 ° C. for 2 to 4 hours; (3) a solvent removal step of cooling to room temperature after reflux and removing the organic solvent; (4) heat removal step of the obtained powder after solvent removal in a vacuum oven at 120 to 160 ℃; Coating method of aluminum nitride for thermal conductive paste coated with an organic surface treatment agent, characterized in that made.