JP6347644B2 - Surface-modified silica powder and slurry composition - Google Patents

Description

The present invention relates to a surface-modified silica powder.

In recent years, with the increase in speed, size, weight, and functionality of electronic devices, printed wiring boards that support high-density mounting and wiring miniaturization have been developed. Multilayer build-up boards have problems such as cracking due to differences in thermal expansion coefficient between insulating layers and copper wiring and IC chips, and heat resistance during manufacturing. Therefore, low thermal expansion is required.

In order to reduce the coefficient of thermal expansion of the substrate, there are known methods such as a method of highly filling a matrix resin such as an epoxy resin with a filler such as silica powder, and a method using a rigid resin. However, when the filler is highly filled in the resin, the dispersibility of the filler is lowered, and the fluidity and moldability are significantly lowered. Further, in the case of thinning, there is a problem that the insulation reliability is lowered because the rigidity of the substrate itself is low.

In order to disperse the filler in the resin, it is effective to control the surface treatment state. Silanol groups exist on the silica particle surface as a reaction site with a surface treatment agent such as a silane coupling agent. By treating the surface treatment agent, the dispersibility of the silica in the resin is improved, and the resin The mechanical strength of the cured product has been improved.

In order to exhibit the function of the surface treatment agent, it is important to uniformly treat the surface and the amount of the surface treatment agent added. In Patent Document 1, the number of functional groups per unit surface area (nm ² ) in the silane coupling agent and organosilazane is specified. In Patent Document 2, the surface treatment layer of the metal oxide surface-treated particles treated with the silane coupling agent is defined. By achieving the state, high dispersion is achieved by controlling the surface state. However, when the addition amount of the surface treatment agent is increased, there is a problem that the amount of the non-reactive surface treatment agent that has not reacted with the surface increases and the mechanical strength is lowered.

JP 2012-214554 A JP 2005-298740 A

Common surface treatment methods include a wet treatment method and a dry treatment method. In the wet treatment method, the reaction rate to the silica surface with respect to the addition amount of the surface treatment agent is about 10%, the non-reactive surface treatment agent is excessively present, and silica dispersion stability in varnish cannot be obtained. There was a problem that the mechanical strength was lowered. In the dry surface treatment method, the reaction rate is very high, but the reaction between the surface treatment agents preferentially proceeds, and a non-uniform reaction layer is formed on the surface of the silica particles. was there. From the above, it has been difficult to obtain silica powder in which the reaction amount of the surface treatment agent is large compared to the non-reaction amount, the adhesiveness to the resin is high, and the drop off from the resin matrix is small.

The present invention has been made in view of the above, and provides a resin cured product having a high reaction amount of a surface treatment agent to the surface of silica particles, in which silica particles are well dispersed, and has excellent substrate strength. It is a problem to be solved.

The present invention employs the following means in order to solve the above problems.
(1) The reaction amount (A) of the silane coupling agent on the silica particle surface is 1.5 to 3.0 per unit surface area (nm ² ), and the non-reaction amount (B) is the reaction amount per unit surface area (nm ² ). Ri 0.1 to 0.6 Baidea of (a), surface modification spherical silica powder BET specific surface area of Ru 3~45m ² / g der.
( 2 ) A slurry composition comprising the surface-modified spherical silica powder according to (1 ) .
( 3 ) The resin composition using the slurry composition as described in said ( 2 ).

The surface-modified silica powder has a reaction layer and a non-reaction layer. The reaction layer is a layer in which the silanol groups on the silica surface and the silane coupling agent are chemically adsorbed. By the presence of the reaction layer, an effect of suppressing aggregation of silica in the resin is expressed.
The non-reactive layer is a layer of a silane coupling agent that is physically adsorbed on the surface of the reaction layer or the surface of the silica particles. The presence of the non-reactive layer improves the compatibility with the resin. Since the non-reactive layer is physically adsorbed, it can be removed by a cleaning process using an organic solvent.

The surface-modified silica powder of the present invention controls the reaction layer and the non-reaction layer of the silica particles subjected to the silane coupling treatment, so that the dispersion is good and the fluidity of the slurry composition is extremely high. It is possible to provide a resin cured product with few aggregates of particles.

The present invention is a silica powder surface-modified with a silane coupling agent, and the reaction amount (A) of the surface treatment agent on the surface of the silica particles is 1.5 to 3.0 per unit surface area (nm ² ). The surface-modified silica powder, wherein the non-reactive amount (B) of the surface treatment agent on the surface of the silica particles is 0.1 to 0.6 times the reactive amount (A) per unit surface area (nm ² ) It is.

The reaction amount of the silane coupling agent is 1.5 to 3.0 / nm ² . When the reaction amount is less than 1.5 / nm ² , the compatibility with the resin is not improved, so that excellent mechanical strength cannot be obtained. If it exceeds 3.0 / nm ² , the reaction between the silane coupling agents preferentially proceeds and aggregation occurs. A preferable reaction amount is 1.8 to 2.8 / nm ² .
The non-reaction amount is 0.1 to 0.6 times the reaction amount (pieces) per unit surface area (nm ² ). If it is less than 0.1 times or more than 0.6 times, the silica dispersion stability in the varnish cannot be obtained, so that the mechanical strength is lowered.

The reaction amount and non-reaction amount of the silane coupling agent can be determined from the carbon amount result using a C / S analyzer (CS-444LS, manufactured by LECO). The surface-treated silica powder has a reaction layer and a non-reaction layer. Since the non-reactive layer is physically adsorbed, it can be removed by a cleaning process using an organic solvent. Since the silanol group on the silica surface and the silane coupling agent are chemically adsorbed, the reaction layer is not removed even by washing with an organic solvent. That is, the silica powder before washing has a reaction layer and a non-reaction layer, and only the reaction layer exists in the silica powder after washing. The non-reaction amount can be determined by the formula (2) from the difference between the carbon amount in the silica powder before washing and the carbon amount in the silica powder after washing.
The reaction amount and the non-reaction amount are represented by the following formulas (1) and (2).
(1) Reaction amount (pieces / nm ² ) =
[Carbon amount (% by mass) in silica powder after washing / (number of carbons of SC agent × 12.01) / 100] (mol / g) / BET specific surface area (m ² /g)×6.02×10 ^{23/10 18}
SC agent: silane coupling agent 12.01: atomic weight of carbon 10 ¹⁸ : unit conversion from m ² to nm ² (2) non-reacted amount (pieces / nm ² ) =
[Carbon amount in silica powder before washing (% by mass) −Carbon amount in silica powder after washing (% by mass) / (Number of carbons of SC agent × 12.01) / 100] (mol / g) / BET specific surface area ^(m 2 ^{/g)×6.02×10 23/10 18}
SC agent: Silane coupling agent 12.01: Atomic weight of carbon 10 ¹⁸ : Unit conversion from m ² to nm ²

The specific surface area of the spherical silica powder of the present invention is a value based on the BET method, and can be measured using “MacsorbHM model-1208” (manufactured by MACSORB) as a specific surface area measuring machine.
From the viewpoint of the amount of reaction sites present on the surface of the silica particles, the BET specific surface area is preferably in the range of ³ to 45 m ² / g.

A method for producing the surface-modified spherical silica powder will be described.
The method for producing a spherical silica powder constituting the present invention is to supply a metal powder slurry into a high-temperature flame composed of a combustible gas and an auxiliary combustion gas in a production furnace, and vaporize and oxidize the metal powder in the flame. Is obtained. When obtaining the silica powder, the silicon powder is used, and the particle size, BET specific surface area of the obtained silica powder can be adjusted by adjusting the particle diameter, supply amount, flame temperature, etc. of the metal silicon powder to be used. Is possible.

The spherical silica powder of the present invention is subjected to a surface treatment to become a surface-modified spherical silica powder. By performing the surface treatment in advance, aggregation of the silica particles can be suppressed, and the silica particles can be favorably dispersed in the resin composition. The silane coupling treatment of the spherical silica powder can be performed using various known silane coupling agents. As a silane coupling agent, epoxy silane such as γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, aminopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, etc. Examples thereof include vinyl silanes such as aminosilane, vinyltrimethoxysilane, and acrylic silanes such as acryloxytrimethoxysilane.

The surface treatment with a silane coupling agent is performed by spraying a basic aqueous solution containing a hydrolyzed silane coupling agent in a state where silica powder is mixed in a treatment vessel using an ultrasonic atomizer in advance. After making a coupling agent contact the surface of a silica particle, it processes by a wet disperser.

  The hydrolyzed silane coupling agent is prepared using a basic aqueous solution mixed with methanol. If the hydrolysis reaction proceeds, the molar ratio of the materials constituting the basic aqueous solution is not particularly limited, but since it has three hydrolyzable groups per silane coupling agent, silane coupling agent: water: methanol. = 1: 3: 1 is preferable.

Examples of the basic aqueous solution include organic amines, silazanes, solutions containing a cyclic compound containing nitrogen, and amine-based silane coupling agents. The pH of the aqueous solution is not particularly limited, but when the hydrolysis and polycondensation reaction of the silane coupling agent proceeds excessively, the aqueous solution becomes cloudy and forms a polymer layer before reacting with the surface of the silica particles. From the viewpoint of reaction rate control, the pH is preferably in the range of 10-12.

  An ultrasonic atomizer is not specifically limited, What is necessary is just to use a well-known thing. The spray size during ultrasonic spraying depends on the frequency of ultrasonic vibration, and the higher the frequency, the smaller the spray size. A preferred spray size is 1 μm or less.

In the silane coupling treatment of the present invention, an ultrasonic sprayer is used to uniformly adsorb the silane coupling agent on the surface of the silica particles in advance, and then in various organic solvents, water dispersibility is high, a bead mill, It is characterized by performing a dispersion treatment using a wet disperser such as a high-pressure homogenizer, and a high reaction rate of the silane coupling agent can be realized.

  The solution of the silica powder subjected to the silane coupling treatment may be pulverized after the silane coupling treatment. The powdering step is not particularly limited, but a step of evaporating the organic solvent and water by heating and reducing the pressure is preferable.

The slurry composition will be described.
The surface-modified silica powder can be suitably used as a slurry composition using water or an organic solvent. The type of the organic solvent in which the silica particles are dispersed is not particularly limited. What is necessary is just to select according to resin. For example, polar solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, and ethyl acetate are used.
Of these, methyl ethyl ketone is particularly preferable.

The dispersion treatment may be performed using equipment such as a ball mill, an ultrasonic disperser, various mixers, and a high-pressure homogenizer. In order to prevent the slurry from being modified, it is desirable to perform the production in a non-oxidizing atmosphere such as a nitrogen atmosphere.

  The content of the surface-modified silica powder contained in the slurry composition is not particularly limited, but is preferably 75.0% by mass or less from the viewpoint of moldability of the resin composition. When it exceeds 75.0% by mass, dispersion treatment becomes difficult.

The resin composition will be described.
When manufacturing a resin substrate such as a package substrate or an interlayer insulating film using the slurry composition, it is preferable to employ an epoxy resin as the resin.

The epoxy resin used in the resin composition is not particularly limited, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, naphthalene type epoxy resin, and phenoxy type epoxy resin. Can be mentioned. One of these can be used alone, two or more having different important molecular weights can be used in combination, and one or two or more can be used.
Among these epoxy resins, bisphenol A type epoxy resins are particularly preferable.

  Although the resin composition of this invention should just use a well-known hardening | curing agent, a phenol type hardening | curing agent can be used. As the phenolic curing agent, a phenol novolac resin, an alkylphenol novolac resin, polyvinylphenols and the like can be used alone or in combination of two or more.

  As for the compounding quantity of the said phenol hardening | curing agent, the equivalent ratio (phenolic hydroxyl group equivalent / epoxy group equivalent) with an epoxy resin is less than 1.0, and 0.1 or more are preferable. As a result, there remains no unreacted phenol curing agent, and the moisture absorption heat resistance is improved.

The amount of spherical silica powder blended in the resin composition is preferably large from the viewpoints of heat resistance and coefficient of thermal expansion. It is desirable that it is 80 mass% or more with respect to the whole mass of a resin composition.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
(Examples 1-9)
Preparation of surface-modified silica powder (1) Example 1
A spherical silica powder (SFP-30M: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle diameter of 0.6 μm and a BET specific surface area of 5.5 m ² / g produced by a metal powder slurry method was charged into a 0.5 kg processing container. As a silane coupling agent, 4.3 g of γ-glycidoxypropyltrimethoxysilane “KBM-403” corresponding to 4.0 per unit area (nm ² ) (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 236.3), 0.99 g of ion-exchanged water and 0.59 g of methanol were weighed, and hexamethyldisilazane “SZ-31” (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 166.5) was used as a basic substance. A basic solution containing a silane coupling agent was prepared by adding 3 times the molar amount. Subsequently, the silica powder was sprayed using an ultrasonic sprayer under the conditions of a spray amount of 2.5 L / min, a frequency of 1.6 MHz, and an N ₂ pressure of 0.04 MPa. Then, after mixing with methyl ethyl ketone to prepare a slurry with a solid content of 70% by weight, using a bead mill, a bead diameter of 500 μm, a bead filling rate of 65 vol%, a peripheral speed of 7 m / sec, a flow rate of 4 L / min, and a pass of 1 Pass. And dispersed. Finally, surface-modified silica powder was obtained by vacuum drying at 50 ° C. under vacuum.
(2) Example 2
In the surface treatment of Example 1, the treated powder is a spherical silica powder (SFP-20M: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 0.3 μm and a BET specific surface area of 13 m ² / g, and a silane coupling agent. Example except that 2 g of γ-glycidoxypropyltrimethoxysilane “KBM-403” (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 236.3), 1.4 g of ion-exchanged water, and 2.3 g of methanol were used. In the same manner as in Example 1, surface-modified silica powder was obtained.
(3) Example 3
In the surface treatment of Example 1 above, Example 1 was used except that 2.7 g of vinyltrimethoxysilane “KBM-1003” (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 148.2) was used as the silane coupling agent. Similarly, surface-modified silica powder was obtained.
(4) Example 4
In the surface treatment of Example 1, the treated powder was a spherical silica powder (SFP-20M: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 0.3 μm and a BET specific surface area of 13 m ² / g, and a silane coupling agent. Except that 4 g of vinyltrimethoxysilane “KBM-1003” (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 148.2), 1.4 g of ion-exchanged water, and 2.3 g of methanol were used, the same procedure as in Example 1 was performed. A surface-modified silica powder was obtained.
(5) Example 5
In the surface treatment of Example 1, as a silane coupling agent, 3.5 g of N-phenylaminopropyltrimethoxysilane “KBM-573” corresponding to 3.0 per unit area (nm ² ) (manufactured by Shin-Etsu Chemical Co., Ltd.) Surface modified silica powder was obtained in the same manner as in Example 1, except that molecular weight 255.4), 0.74 g of ion exchange water, and 0.44 g of methanol were used.
(6) Example 6
In the surface treatment of Example 1, the treated powder was a spherical silica powder (SFP-20M: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 0.3 μm and a BET specific surface area of 13 m ² / g, and a unit area as a silane coupling agent. 5.5 g of N-phenylaminopropyltrimethoxysilane “KBM-573” (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 255.4), which is 2.0 per (nm ² ), 0.69 g of ion-exchanged water, A surface-modified silica powder was obtained in the same manner as in Example 1 except that 2 g of methanol was used.
(7) Example 7
In the surface treatment of Example 1, a surface-modified silica powder was obtained in the same manner as in Example 1 except that a high-pressure homogenizer was used as the wet disperser.
(8) Example 8
In the surface treatment of Example 1, the powder to be treated was a spherical silica powder (SFP-20M: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 0.3 μm and a BET specific surface area of 13 m ² / g, and a high-pressure homogenizer as a wet disperser. A surface-modified silica powder was obtained in the same manner as in Example 2 except that was used.
(9) Example 9
In the surface treatment of Example 1, the treated powder was a spherical silica powder (UFP-40: manufactured by Denki Kagaku Kogyo Co., Ltd.) having an average particle size of 0.1 μm and a BET specific surface area of 45 m ² / g, and 26. 5 g of γ-glycidoxypropyltrimethoxysilane “KBM-403” (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 236.3), 5.6 g of ion-exchanged water, 4.2 g of methanol, and an ultrasonic homogenizer were used. Except that, surface-modified silica powder was obtained in the same manner as in Example 1.

(Comparative Examples 1-8)
(10) Comparative Example 1
In the surface treatment of Example 1, a surface-modified silica powder was obtained in the same manner as in Example 1 except that no basic substance was used.
(11) Comparative Example 2
In the surface treatment of Example 2, a surface-modified silica powder was obtained in the same manner as in Example 1 except that no basic substance was used.
(12) Comparative Example 3
In the surface treatment of Example 3, a surface-modified silica powder was obtained in the same manner as in Example 1 except that no basic substance was used.
(13) Comparative Example 4
In the surface treatment of Example 5, a surface-modified silica powder was obtained in the same manner as in Example 1 except that no basic substance was used.
(14) Comparative Example 5
In the surface treatment of Example 1, a surface-modified silica powder was obtained in the same manner as in Example 1 except that liquid spraying with a two-fluid spray nozzle was used as a spraying method for the surface treatment agent.
(15) Comparative Example 6
In the surface treatment of Example 2, a surface-modified silica powder was obtained in the same manner as in Example 1 except that liquid spraying with a two-fluid spray nozzle was used as a spraying method for the surface treatment agent.
(16) Comparative Example 7
In the surface treatment of Example 3, a surface-modified silica powder was obtained in the same manner as in Example 1 except that liquid spraying with a two-fluid spray nozzle was used as a spraying method for the surface treatment agent.
(17) Comparative Example 8
In the surface treatment of Example 5, a surface-modified silica powder was obtained in the same manner as in Example 1 except that liquid spraying with a two-fluid spray nozzle was used as a spraying method for the surface treatment agent.
(18) Comparative Example 9
In the surface treatment of Example 6, a surface-modified silica powder was obtained in the same manner as in Example 5 except that the bead mill was not used.
(19) Comparative Example 10
In the surface treatment of Example 5, a surface-modified silica powder was obtained in the same manner as in Example 5 except that liquid spraying with a two-fluid spray nozzle was used as a spraying method for the surface treatment agent.

The measuring method of specific surface area and carbon content is shown below.
(Specific surface area measurement)
1.0 g of spherical silica powder was weighed, put into a measurement cell, and after pretreatment, the BET specific surface area value was measured. The measuring machine used was “Macsorb HM model-1208” (manufactured by MACSORB). Pretreatment was performed under the following conditions.
Degassing temperature: 300 ° C
Degassing time: 18 minutes Cooling time: 4 minutes (carbon amount measurement)
After mixing 35 g of acetone with 5 g of the pretreatment slurry of the reaction amount measurement sample, the sample was treated for 10 minutes using a shaker. Next, the supernatant was discarded after solid-liquid separation using a centrifuge. After mixing the sediment and 35 g of acetone, the same operation as described above was performed. Finally, the sediment was dried to obtain a sample for measuring the reaction amount.
Carbon amount measurement The carbon amount was measured using LECO's trade name “CS-444LS type” for the carbon / sulfur simultaneous analyzer and JSS061-8 for the carbon standard sample.

(Production of cured resin)
20.0 parts by mass of bisphenol A type epoxy resin “EPICLON-850” (manufactured by DIC Corporation, epoxy equivalent 186 g / eq) as an epoxy resin, novolak type phenol resin “PSM-4261” (Gunei Chemical Industry Co., Ltd.) as a curing agent 11.7 parts by mass of hydroxyl group equivalent 106 g / eq, softening point 80 ° C., 0.3 part by mass of 2-phenylimidazole (2PZ) “manufactured by Shikoku Kasei Kogyo Co., Ltd.” as a curing accelerator It melt | dissolved in 100 mass parts of slurry compositions obtained in the manufacture process, and prepared the resin composition (epoxy resin varnish). This resin composition was applied to a substrate using an applicator, vacuum degassed at 50 ° C., and then dried at a temperature of 150 ° C. for 2 hours to obtain a cured resin. The fluidity and dispersibility of the obtained resin composition and the moldability of the cured resin were evaluated according to the methods shown below. The evaluation results are shown in Tables 1-3.

The evaluation methods of the resin composition and the cured resin product are shown in the following (1) to (4).
(1) Fluidity / Varnish Viscosity The viscosity of the resin composition after vacuum degassing was measured with an E-type viscometer (manufactured by Toki Sangyo Co., Ltd .: TVE-10) at 20 rpm (measurement temperature 25 ° C.). At this time, 1.0 Pa · s or more was regarded as defective.
(2) Dispersion stability The obtained resin composition was allowed to stand at a temperature of 40 ° C. and a humidity of 80% for 1 day, and then measured with a particle size distribution analyzer “Model LS-230” (manufactured by Beckman Coulter). At this time, when a particle size distribution of 0.01% or more was present at a position of 5 μm or more, it was regarded as defective.
(3) Resin Adhesiveness / Fracture Surface SEM Observation The cured resin produced in Example 1 and Comparative Example 1 was broken and the fracture surface was observed with SEM (magnification: 10,000). The degree of particle dropout from the resin matrix was compared. A defect was determined when there were 5 or more traces of particles dropped out per field of view.
(4) Formability / Agglomerates of silica particles The surface shape inspection system KURASURF-PH (manufactured by Kurashiki Boseki Co., Ltd.) is used to determine the number of aggregates of silica particles of 10 μm or more present in an area of 1 cm ³ of the obtained resin cured product. Was used to detect surface irregularities by irradiating a fringe pattern and shifting the phase difference, and evaluated as moldability according to the following criteria.
Each code is the following evaluation criteria.
A: No aggregate less than 10 μm ○: Less than 5 aggregates less than 10 μm ×: 5 or more aggregates greater than 10 μm

  As is clear from the comparison between Examples and Comparative Examples, when the spherical silica powder of the present invention is filled in an epoxy resin, the dispersion of the spherical silica particles is good, the fluidity of the slurry composition is extremely high, and the silica particles A cured resin product having a small amount of aggregate was obtained.

The slurry composition and resin composition of the present invention can be used for a semiconductor package substrate in the field of electronic equipment such as a printed wiring board.

Claims (3)

The reaction amount (A) of the silane coupling agent on the surface of the silica particles is 1.5 to 3.0 per unit surface area (nm ² ), and the non-reaction amount (B) is the reaction amount (A) per unit surface area (nm ² ). 0.1-0.6 Baidea is, the surface modification spherical silica powder BET specific surface area of Ru 3~45m ² / g der of. A slurry composition comprising the surface-modified spherical silica powder according to claim 1 . A resin composition using the slurry composition according to claim 2 .