JP2015140389A - Encapsulation material for mold under fill and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encapsulation material for MUF for further flowability improvement.SOLUTION: It has a filler containing melting silica surface treated by N-phenyl-3-aminopropyl trimethoxysilane and spherical silica manufactured by a VMC method with mass ratio in a range of 100:0 to 50:50 and a resin material. By dispersing the melting silica surface treated by N-phenyl-3-aminopropyl trimethoxysilane in the resin material, flowability is improved compared to cases without conducting a surface treatment or using other surface treatment agent.

Description

  The present invention relates to a mold underfill sealing material and a method for manufacturing the same.

  In recent years, with the advancement of semiconductor technology, digital home appliances and mobile terminals have been increased in speed and functionality. And the gap between a chip | tip and a board | substrate at the time of mounting the high performance semiconductor which bears the function of these apparatuses on a board | substrate is decreasing year by year.

  This gap is generally underfilled with a liquid sealing material. In recent years, in some semiconductor devices, in order to reduce assembly costs and man-hours, technology development of mold underfill (hereinafter referred to as “MUF”), which is a molding method that performs underfill by transfer molding, has been promoted. Is already in mass production (for example, Patent Document 1).

  One of the problems with MUF is the filling property of the sealing material under the chip. In order to perform filling quickly and reliably, it is necessary to increase the fluidity (lower the viscosity) of the sealing material.

JP 2011-132268 A

  This invention is completed in view of the said situation, and makes it the problem which should be solved to provide the sealing material for MUF aiming at the further fluid improvement, and its manufacturing method.

(A) The mold underfill sealing material of the present invention that solves the above problems comprises fused silica surface-treated with N-phenyl-3-aminopropyltrimethoxysilane and spherical silica prepared by the VMC method. A filler contained in a mass ratio in the range of 100: 0 to 50:50;
Resin material,
Have

  When fused silica that has been surface-treated with N-phenyl-3-aminopropyltrimethoxysilane is dispersed in the resin material, the fluidity is improved compared to the case where surface treatment is not performed or when other surface treatment agents are used. The present invention has been completed.

The sealing material for MUF disclosed in the above (a) can be added with any one or more of the components (b) and (c) described below.
(B) having silica particles having a volume average particle size smaller than that of the fused silica and not less than 5 nm and not more than 300 nm. The fluidity is further improved by further mixing silica particles having a small particle diameter. The silica particles may be surface-treated with the aforementioned N-phenyl-3-aminopropyltrimethoxysilane.
(C) The silica particles are
The volume average particle size of the primary particles is 300 nm or less, the bulk density is 450 g / L or less,
It has a functional group represented by the formula (1): -OSiX ¹ X ² X ³ and a functional group represented by the formula (2): -OSiY ¹ Y ² Y ³ on the surface. (In the above formulas (1) and (2); X ¹ is a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group; X ² , X ³ Are independently selected from —OSiR ₃ and —OSiY ⁴ Y ⁵ Y ⁶ ; Y ¹ is R; Y ² and Y ³ are each independently selected from R and —OSiY ⁴ Y ⁵ Y ⁶ .Y ⁴ is an R; ^{Y 5} and ^{Y 6} is selected from R and -OSiR ₃ independently;. R is independently selected from alkyl groups of 1 to 3 carbon atoms Incidentally, ^{X 2} , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ are any of the adjacent functional groups X ² , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ , and —O—. May be combined with each other.)

(D) The mold underfill sealing material manufacturing method that solves the above problems is crushed so that the bulk density is 450 g / L or less with respect to the raw material silica particles whose primary particles have a volume average particle diameter of 300 nm or less. Crushing process to
The silica particles obtained in the crushing step, fused silica having a volume average particle size larger than the primary particles of the silica particles, and spherical silica prepared by the VMC method are used in a mass ratio of 100: 0 to 50:50. A mixing step of mixing the filler and the resin material contained in the range of
Have
At least the filler is surface-treated with N-phenyl-3-aminopropyltrimethoxysilane,
The raw silica particles are
A surface treatment step of surface treatment with a silane coupling agent and an organosilazane in a liquid medium containing water;
Removing the liquid medium;
It is processed in the pretreatment process with
The silane coupling agent has three alkoxy groups, a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group,
The molar ratio of the silane coupling agent to the organosilazane is the silane coupling agent: the organosilazane = 1: 2 to 1:10.

In the manufacturing method (d) described above, the following components (e) can be added.
(E) The surface treatment step includes
A first treatment step of treating with the silane coupling agent;
A second treatment step of treating with the organosilazane,
The second processing step is performed after the first processing step.

  The mold underfill sealing material of the present invention is excellent in fluidity by performing surface treatment with a specific surface treatment agent.

It is a graph which shows the relationship between the viscosity of each test sample in an Example, and a share rate.

  Hereinafter, the sealing material for MUF and the manufacturing method thereof according to the present invention will be described in detail based on the embodiments. The sealing material for MUF of the present invention can be used as a sealing material for sealing a semiconductor device or the like by transfer molding.

  Here, “mold underfill: MUF” in this specification will be described below. In general, a semiconductor device in which a semiconductor chip mounted on a substrate is sealed with a resin is well known. A flip-chip connection method is known as a technique that meets the demands for further downsizing, thinning, and high density of semiconductor devices. In this connection method, protruding electrodes (bumps) are formed on the circuit surface of the semiconductor chip and directly connected to the electrode terminals of the substrate face down. According to this flip chip connection method, there is an advantage that the semiconductor device can be reduced in thickness because the mounting area of the semiconductor chip is small and it is not necessary to seal the resin up to the wire as in the case of wire bonding connection.

  In the case of the flip chip connection method, a narrow gap corresponding to the thickness of an electrode of several tens of μm is generated between the mounted semiconductor chip and the substrate. Conventionally, the narrow gap under the chip has been filled (underfilled) with a liquid resin composition using a capillary. After that, the entire chip was resin-sealed (overmolded) with a non-liquid epoxy resin composition by transfer molding. However, since two processes of underfill with a narrow gap and overmolding of the entire chip are required, as a technique for performing filling of the narrow gap under the chip and sealing of the entire chip with only a non-liquid resin composition. Development of “MUF” is underway. Here, the non-liquid resin composition refers to a resin composition that is solid at room temperature, such as powder, granule, tableted tablet, and the like.

(Encapsulant for MUF)
The sealing material for MUF of this embodiment has a filler and a resin material.
The filler contains fused silica and spherical silica. Fused silica is silica particles produced by the melting method. The melting method is to obtain particles of the desired size by a method such as crushing using silica as a raw material, and then heat and melt by supplying the particles to a high temperature such as a flame while floating in a gas such as air. This is a method for increasing the sphericity. Spherical silica is silica prepared by the VMC method. The VMC method is a method of producing silica particles having high sphericity by forming silica by burning metal silicon particles in an oxidizing atmosphere.

  The mixing ratio of the fused silica and the spherical silica can be arbitrarily determined in the range of 100: 0 to 50:50 by mass ratio. In other words, it means that fused silica is essential and spherical silica in an amount not exceeding the amount can be contained.

  Although it does not specifically limit as a fused silica and a spherical silica, It is desired that a particle size is smaller than the gap of the target object which applies MUF. For example, a volume average particle size of 30 μm or less, 20 μm or less, 15 μm or less, and the like are preferable. Examples of the lower limit of the volume average particle diameter include 10 μm, 5 μm, and 2 μm. Furthermore, it is desirable that the maximum diameter of the contained particles is not more than the size of the gap. For example, the content of particles larger than the same diameter as the gap determined from the size of the gap and the diameter of one third of the gap is desirably 1000 ppm or less, and more desirably 0 ppm or less. In order to reduce the amount of coarse particles, the coarse particles can be removed by classification in the state of the filler alone before mixing, and after the MUF sealing material is prepared, classification (sieving, etc.) is performed to obtain coarse particles. Can also be removed.

Fused silica is surface-treated with N-phenyl-3-aminopropyltrimethoxysilane. The spherical silica is preferably subjected to a surface treatment with N-phenyl-3-aminopropyltrimethoxysilane. The amount with which N-phenyl-3-aminopropyltrimethoxysilane is reacted is not particularly limited, but can be determined based on the amount corresponding to the number of OH groups present on the surface of fused silica or spherical silica, or fused silica or spherical silica. The surface area can be determined based on the surface area, or can be determined based on the mass or volume of the fused silica. The amount or adopts an amount of about 50% to 200% based on the OH group, or to 1.0m per 1 g ² to 20 m approximately ² (measured by the BET method using nitrogen) surface area of the fused silica or spherical silica be able to.

  The surface treatment to fused silica or spherical silica may be performed on single fused silica or spherical silica, or may be performed after being dispersed in a resin material. N-phenyl-3-aminopropyltrimethoxysilane may be used as it is, or may be added in a state dissolved in MEK, MIBK, IPA, water or the like at an arbitrary concentration. Furthermore, the surface treatment may be performed using the entire amount at once, or the surface treatment may be performed by dividing N-phenyl-3-aminopropyltrimethoxysilane into several groups. Furthermore, as a method of reacting N-phenyl-3-aminopropyltrimethoxysilane with the surface, it can also be carried out by bringing it into contact with the surface in a liquid or vaporized state. When reacting in a liquid state, it can be atomized with an atomizer or the like and sprayed. At that time, it is preferable to carry out the stirring of the fused silica and the spherical silica.

  The primary particles of the silica particles have a volume average particle size smaller than that of the fused silica, and the silica particles exhibit a so-called “roller” action between the fused silica and the spherical silica. The addition amount of the silica particles is not particularly limited, but an amount such as 0.1% or more can be added based on the mass of the fused silica. An example of the upper limit of the amount added is 10%.

  Here, it is desirable that the silica particles are substantially present as primary particles in the MUF sealing material. Here, the presence of primary particles means particles in a state where the particles are in contact with each other in a SEM photograph. In particular, it is desirable that the ratio of overlapping particles in the SEM photograph is 10% or less based on the total number.

  Silica particles have a primary particle volume average particle size of 5 nm to 300 nm. In particular, the bulk density is desirably 450 g / L or less. As a volume average particle diameter, 200 nm, 100 nm, 70 nm, 50 nm, 30 nm, and 20 nm are mentioned as a preferable upper limit. Moreover, 10 nm is mentioned as a preferable minimum. The silica particles preferably have a particle size of 500 nm or less, and more preferably 300 nm or less.

  The measurement of the bulk density in this specification is performed using the Tsutsui-Rikagakuki Co., Ltd. product: electromagnetic vibration type | mold beak density measuring device (MVD-86 type | mold). Specifically, after the sample to be measured is put into the upper 500 μm sieve as the sample tank, the sample is dispersed through the two upper and lower 500 μm sieves under electromagnetic acceleration conditions, and dropped into a 100 mL sample container. The mass was measured, and the bulk density was calculated from the mass and volume. In order to prevent a decrease in bulk density due to its own weight, measurement should be performed within 1 hour after dropping.

  Preferred upper limits for the bulk density include 400 g / L, 370 g / L, 350 g / L, 300 g / L, 280 g / L, and 250 g / L. A preferred lower limit is 100 g / L. By setting the bulk density to a value below these upper limits, primary particles can be separated more reliably. Moreover, when the bulk density is set to a value higher than these lower limits, the bulk is small and the handling becomes easy.

  In the silica particles of this embodiment, functional groups containing carbon are introduced on the surface. Since the specific structure of the functional group containing carbon and the method of introducing it onto the surface of the silica particles will be described in detail in the production method described later, description thereof is omitted here.

  The resin material can be finally solidified in the presence of the above-described filler to seal the semiconductor device. The resin material contains one or more compounds and is either one that melts by heating and exhibits fluidity (such as a thermoplastic resin) or one that is initially liquid and solidifies by reaction (such as a thermosetting resin). May be. Examples of the resin material include a combination of an epoxy resin and a curing agent.

  The mixing ratio of the filler and the resin material is not particularly limited, but as a result of improving the fluidity by the surface treatment, a large amount of filler can be contained. For example, 60% or more of the filler can be contained based on the total mass. Although it does not specifically limit as an upper limit, About 90% is mentioned.

(Method for producing sealing material for MUF)
The manufacturing method of the sealing material for MUF of this embodiment is a method which mixes the silica particle manufactured by performing a crushing process with respect to raw material silica particles to fused silica or spherical silica (mixing process). This is a method that can be suitably used for manufacturing the MUF sealing material of the present embodiment described above. The raw material silica particles have a large proportion of primary particles bonded together, but the bonds can be separated in the crushing step.

  The mixing step is a step of mixing silica particles with fused silica or spherical silica, and is not particularly limited. As described above, silica particles crushed to primary particles in a dry state are directly mixed with metal nitride particles.

  In the mixing step, N-phenyl-3-aminopropyltrimethoxysilane is added to perform surface treatment. Addition can be performed when fused silica or spherical silica is used alone or after mixing silica particles.

  In the mixing step, resin materials can be mixed at the same time.

  The method for the crushing step is not particularly limited. Preferably, a method of adding an effect of separating the aggregates of the aggregates is preferable, and a method that does not destroy the primary particles constituting the aggregates is preferable. For example, it can be performed by a method similar to pulverization performed in a dry state, and examples thereof include a jet mill, a pin mill, and a hammer mill. It is particularly desirable to use a jet mill. The final stage of the process is judged from the value of the bulk density of the raw silica particles. After the proper bulk density, it can be selected from the range described above. The jet mill is a device that performs pulverization by placing raw material silica particles in an air stream. Any type of jet mill is acceptable. Crushing by a jet mill is desirably performed by a dry method.

  The raw material silica particles have a primary particle size volume average particle size of 300 nm or less. In addition, examples of the upper limit include 200 nm, 100 nm, 70 nm, and 50 nm. The method for producing the raw material silica particles is not particularly limited. For example, a water glass method, an alkoxide method, and a VMC method can be exemplified, and it is desirable to employ the water glass method. The water glass method is a method of precipitating raw material silica particles by performing ion exchange, introduction / desorption of substituents by chemical reaction, control of pH, temperature, and the like on water glass. For example, an aqueous slurry in which nanometer order silica particles are dispersed can be prepared by ion exchange of water glass with an ion exchange resin. The particle diameter of the secondary particles constituting the raw silica particles is not particularly limited, but the volume average particle diameter may be 10 μm or more, 100 μm or more. Furthermore, the raw material silica particles can be produced by dissolving metal silicon in an alkali solution or the like and then depositing it (a method similar to the water glass method).

  A pretreatment process is applied to the preparation of the raw silica particles. The pretreatment process includes a surface treatment process and a process for removing the liquid medium (solidification process). The surface treatment step is a step of performing a surface treatment with a silane coupling agent and an organosilazane in a liquid medium containing water (water, one containing alcohol in addition to water). The silane coupling agent has three alkoxy groups and a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group. The molar ratio of the silane coupling agent to the organosilazane is (silane coupling agent) :( organosilazane) = 1: 2 to 1:10.

  The surface treatment step includes a first treatment step for treating with the above-described silane coupling agent and a second treatment step for treating with organosilazane thereafter.

In the surface treatment step, the functional group represented by the formula (1): -OSiX ¹ X ² X ³ and the formula (2): -OSiY ¹ Y ² Y are applied to the silica particles obtained by the above-described method. ³ is a step of obtaining raw material silica particles in which the functional group represented by ³ is bonded to the surface. Hereinafter, the functional group represented by the formula (1) is referred to as a first functional group, and the functional group represented by the formula (2) is referred to as a second functional group.

X ¹ in the first functional group is a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group. X ² and X ³ are —OSiR ₃ or —OSiY ⁴ Y ⁵ Y ⁶ , respectively. Y ⁴ is R. Y ⁵ and Y ⁶ are each R or —OSiR ₃ .

Y ¹ in the second functional group is R. Y ² and Y ³ are —OSiR ₃ or —OSiY ⁴ Y ⁵ Y ⁶ , respectively.

The more —OSiR ₃ contained in the first functional group and the second functional group, the more R on the surface of the raw silica particles. As the R (the alkyl group having 1 to 3 carbon atoms) contained in the first functional group and the second functional group increases, the raw silica particles are less likely to aggregate.

Regarding the first functional group, when X ² and X ³ are each —OSiR ₃ , the number of R is minimized. Further, ^{X 2} and ^{X 3} is -OSiY ⁴ Y ⁵ Y ^6, respectively, ^and, if Y 5, ^{Y 6} is -OSiR ₃ respectively, the number of R is maximized.

Regarding the second functional group, when Y ² and Y ³ are each —OSiR ₃ , the number of R is minimized. Further, ^{Y 2} and ^{Y 3} are -OSiY ⁴ Y ⁵ Y ^6, respectively, ^and, if Y 5, ^{Y 6} is -OSiR ₃ respectively, the number of R is maximized.

The number of X ¹ contained in the first functional group, the number of R contained in the first functional group, and the number of R contained in the second functional group are the abundance ratio of R and X ¹ What is necessary is just to set suitably according to the particle size and use of a silica particle.

^{Incidentally, X 2, X 3, Y} 2, Y 3, Y 5, and any of ^{Y 6, X} 2 of the adjacent ^{functionality, X 3, Y 2, Y} 3, Y 5, and any ^{Y 6} You may combine with heel -O-. For example, any one of the first functional group X ² , X ³ , Y ⁵ , and Y ⁶ is the first functional group adjacent to the first functional group X ² , X ³ , Y ⁵ , and It may be bonded to any of Y ⁶ by —O—. Similarly, any of Y ² , Y ³ , Y ⁵ , and Y ⁶ of the second functional group is replaced with Y ² , Y ³ , Y ⁵ , Y ² of the second functional group adjacent to the second functional group. And Y ⁶ may be bonded to each other by —O—. Furthermore, any one of the first functional groups X ² , X ³ , Y ⁵ , and Y ⁶ is the second functional group adjacent to the first functional group, Y ² , Y ³ , Y ⁵ , And Y ⁶ may be bonded to each other by —O—.

In the raw material silica particles, the presence ratio of the first functional groups and second functional groups is 1: 12-1: if 60, the surface of the raw material silica particles and X ¹ and R are present good balance. For this reason, the raw material silica particle whose abundance ratio of the first functional group and the second functional group is 1:12 to 1:60 is particularly excellent in the affinity for the resin and the aggregation suppressing effect. Further, if X ¹ is 0.5 to 2.5 per unit surface area (nm ² ) of the raw silica particles, a sufficient number of first functional groups are bonded to the surface of the raw silica particles, and the first There are also a sufficient number of Rs derived from the functional group and the second functional group. Therefore, also in this case, the affinity for the resin and the aggregation suppressing effect of the raw silica particles are sufficiently exhibited.

In any case, R per unit surface area (nm ² ) of the raw silica particles is preferably 1 to 10. In this case, the balance between the number of X ¹ present on the surface of the raw silica particles and the number of R is improved, and both the affinity for the resin and the aggregation suppressing effect of the raw silica particles are exhibited in a well-balanced manner.

In the raw material silica particles, it is preferable that all of the hydroxyl groups present on the surface of the silica particles are substituted with the first functional group or the second functional group. If the sum of the first functional group and the second functional group is 2.0 or more per unit surface area (nm ² ) of the raw silica particles, the raw silica particles were present on the surface of the silica particles. It can be said that almost all of the hydroxyl groups are substituted with the first functional group or the second functional group.

The raw silica particles have R on the surface. This can be confirmed by an infrared absorption spectrum. Specifically, when the infrared absorption spectrum of the raw silica particles is measured by the solid diffuse reflection method, there is a maximum absorption of C—H stretching vibration at 2962 ± 2 cm ⁻¹ .

  Further, as described above, the raw material silica particles hardly aggregate.

  Note that the raw silica particles can be dispersed again by ultrasonic treatment even if they are slightly agglomerated. Specifically, the raw silica particles can be substantially dispersed to primary particles by irradiating the raw silica particles dispersed in methyl ethyl ketone with ultrasonic waves having an oscillation frequency of 39 kHz and an output of 500 W. The ultrasonic irradiation time at this time may be 10 minutes or less. Whether or not the raw material silica particles are dispersed to the primary particles can be confirmed by measuring the particle size distribution. Specifically, when the methyl ethyl ketone dispersion material of the raw material silica particles is measured with a particle size distribution measuring device such as a microtrack device, and there is a particle size distribution of the raw material silica particles, it can be said that the raw material silica particles are dispersed to primary particles.

  Since the raw silica particles hardly aggregate, they can be provided as raw silica particles that are not dispersed in a liquid medium such as water or alcohol. In this case, since no liquid medium is brought in, it is preferably used as a filler for a resin material.

  Further, since the raw silica particles are difficult to aggregate, they can be easily washed with water.

The raw material silica particles are treated in a step of treating the silica particles with a silane coupling agent and an organosilazane (surface treatment step) in a liquid medium containing water. The silane coupling agent has three alkoxy groups and a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group (that is, X ¹ described above). It does not prevent the adoption of the aforementioned N-phenyl-3-aminopropyltrimethoxysilane.

By performing the surface treatment with the silane coupling agent, the hydroxyl group present on the surface of the silica particles is substituted with a functional group derived from the silane coupling agent. The functional group derived from the silane coupling agent is represented by the formula (3); —OSiX ¹ X ⁴ X ⁵ . The functional group represented by the formula (3) is referred to as a third functional group. X ¹ in the third functional group is the same as X ¹ in the functional group represented by the formula (1). X ⁴ and X ⁵ are each an alkoxy group. By surface-treating with organosilazane, the third functional group X ⁴ and X ⁵ are derived from organosilazane —OSiY ¹ Y ² Y ³ (the functional group represented by the formula (2), the second functional group ). When all of the hydroxyl groups present on the surface of the silica particles are not substituted with the third functional group, the hydroxyl groups remaining on the surface of the silica particles are substituted with the second functional group. For this reason, on the surface of the surface-treated raw material silica particles, a functional group represented by the formula (1): -OSiX ¹ X ² X ³ (that is, the first functional group) and a formula (2): -OSiY ^The functional group represented by ¹ Y ² Y ³ is bonded to the functional group (that is, the second functional group). In addition, since the molar ratio of the silane coupling agent and the organosilazane is silane coupling agent: organosilazane = 1: 2 to 1:10, the first functional group and the second functional group in the obtained raw material silica particles are used. The abundance ratio with the functional group is theoretically from 1:12 to 1:60.

In the surface treatment step, the silica particles may be simultaneously surface treated with a silane coupling agent and an organosilazane. Alternatively, the silica particles may first be surface treated with a silane coupling agent and then surface treated with organosilazane. Alternatively, the silica particles may be first surface treated with organosilazane, then surface treated with a silane coupling agent, and then surface treated with organosilazane. In any case, the amount of organosilazane may be adjusted so that all the hydroxyl groups present on the surface of the silica particles are not substituted with the second functional group. The hydroxyl groups present on the surface of the silica particles may all be substituted with the third functional group, or only a part may be substituted with the third functional group, and the other part may be substituted with the second functional group. It may be replaced. All of X ⁴ and X ⁵ contained in the third functional group may be substituted with the second functional group.

A part of organosilazane may be replaced with the second silane coupling agent. As the second silane coupling agent, one having three alkoxy groups and one alkyl group can be used. In this case, X ⁴ and X ⁵ contained in the third functional group are substituted with the fourth functional group derived from the second silane coupling agent. The fourth functional group has the formula (4); - represented by OSiY ¹ X ⁶ X ^7. Y ¹ is the same R as ^{Y 1} in the second functional ^{group, X 6,} X ⁷ is an alkoxy group or a hydroxyl group, respectively. X ⁶ and X ⁷ contained in the fourth functional group are substituted with the second functional group derived from organosilazane, or are substituted with another fourth functional group. In this case, the amount of R present on the surface of the raw silica particles can be further increased. When a part of the organosilazane is replaced with the second silane coupling agent, it is necessary to surface-treat with the organosilazane again after the surface treatment with the second silane coupling agent. This is because X ⁶ and X ⁷ contained in the fourth functional group are finally substituted with the second functional group derived from organosilazane.

When a part of the organosilazane is replaced with the second silane coupling agent, X ⁴ and X ⁵ contained in the first functional group described above are substituted with the second functional group derived from the organosilazane, Substitution with a fourth functional group derived from the second silane coupling agent. When X ⁴ and X ⁵ are substituted with the fourth functional group, X ⁶ and X ⁷ contained in the fourth functional group are substituted with the second functional group or another fourth functional group. Is replaced by If X ^6, X ⁷ contained in the fourth functional group has been replaced by another fourth functional group, X ^6, X ⁷ contained in the fourth functional groups is substituted with the second functional group The For this reason, the second silane coupling agent is an organosilazane set when the surface treatment is performed only with the first coupling agent and the organosilazane (when the organosilazane is not replaced with the second silane coupling agent). A maximum of 5a / 3 mol can be substituted for the amount (a) mol. The amount of organosilazane required in this case is 8a / 3 mol.

  The alkoxy groups of the silane coupling agent and the second silane coupling agent are not particularly limited, but those having a relatively small carbon number are preferred, and those having 1 to 12 carbon atoms are preferred. Considering the hydrolyzability of the alkoxy group, the alkoxy group is more preferably any one of a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

  Specific examples of silane coupling agents include phenyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3 -Aminopropyltrimethoxysilane.

  Any organosilazane may be used as long as it can replace the hydroxyl group present on the surface of the silica particles and the alkoxy group derived from the silane coupling agent with the second functional group described above. preferable. Specific examples include tetramethyldisilazane, hexamethyldisilazane, pentamethyldisilazane, and the like.

  Examples of the second silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, and hexyltriethoxysilane.

  In the surface treatment step, a polymerization inhibitor may be added in order to suppress polymerization of the silane coupling agent or polymerization of the second silane coupling agent. As the polymerization inhibitor, common ones such as 3,5-dibutyl-4-hydroxytoluene (BHT) and p-methoxyphenol (methoquinone) can be used.

  The raw silica particles may be provided with a solidification step after the surface treatment step. The solidification step is a step in which the raw material silica particles after the surface treatment are precipitated with a mineral acid, and the precipitate is washed with water and dried to obtain a solid material of the raw material silica particles. As described above, since general silica particles are very likely to aggregate, it is very difficult to disperse once solidified silica particles. However, since the raw silica particles are difficult to agglomerate, they are difficult to agglomerate even if solidified, and are easily redispersed even if agglomerated. In the washing step, washing is preferably repeated until the electrical conductivity of the extraction water of the raw silica particles (specifically, the water in which the silica particles are immersed at 121 ° C. for 24 hours) is 50 μS / cm or less.

  Examples of the mineral acid used in the solidification step include hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid, and hydrochloric acid is particularly desirable. The mineral acid may be used as it is, but is preferably used as a mineral acid aqueous solution. The concentration of the mineral acid in the aqueous mineral acid solution is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. The amount of the mineral acid aqueous solution can be about 6 to 12 times based on the mass of the raw silica particles to be cleaned.

  The cleaning with the mineral acid aqueous solution can be performed a plurality of times. The washing with the mineral acid aqueous solution is preferably performed after the raw silica particles are immersed in the mineral acid aqueous solution and then stirred. Further, it can be left in the immersed state for 1 to 24 hours, and further for about 72 hours. When it is allowed to stand, stirring can be continued or not stirred. When washing in the mineral acid-containing liquid, it can be heated to room temperature or higher.

  Thereafter, the raw silica particles washed and suspended are collected by filtration and then washed with water. It is desirable that the water used does not contain ions such as alkali metals (for example, 1 ppm or less on a mass basis). For example, ion exchange water, distilled water, pure water and the like. Washing with water is the same as washing with an aqueous mineral acid solution, after the raw silica particles are dispersed and suspended, they can be filtered, or by continuously passing water through the filtered raw silica particles. Is possible. The end of washing with water may be determined by the electrical conductivity of the extracted water described above, or may be the time when the alkali metal concentration in the waste water after washing the raw silica particles becomes 1 ppm or less, It is good also as the time of the alkali metal concentration of extraction water becoming 5 ppm or less. When washing with water, it can be heated to a room temperature or higher.

  Drying of the raw silica particles can be performed by a conventional method. For example, heating or leaving under reduced pressure (vacuum).

  The sealing material for MUF of this invention and its manufacturing method are demonstrated based on an Example. In this example, when mentioning the particle size, the particle size of the secondary particles is described unless there is a description that the particle size of the primary particles.

(Viscosity measurement)
Preparation of test sample 80 parts by mass of fused silica (volume average particle size 5 μm), 20 parts by mass of spherical silica (prepared by VMC method: Admafine: volume average particle size 5 μm), silica particles (manufactured by Admatechs; nano silica) YA010C-SP3; volume average particle size 10 nm) 0.3 parts by mass and ZX-1059 (Toto Kasei) as a resin material were mixed 75 parts by mass to obtain test samples for each test example.

  The filler composed of fused silica and spherical silica was previously surface treated with the following surface treatment agent. Test Example A1, A5 to A7: HMDS, Test Example A2 and A4: N-phenyl-3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-573), Test Example A3, A8: 3-glycid Xylpropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403).

  The reaction of the surface treatment agent was caused to react in an amount of 0.5% by mass based on the mass of the filler. In the reaction, a filler, a compound (surface treatment agent) and the like were put into a mixer and stirred for several hours.

-Viscosity measurement and result The relationship between a shear rate and a viscosity was measured about each test sample of test example A1-A8. The results are shown in FIG. As is apparent from FIG. 1, the test samples of Test Examples A2 and A4 that employ N-phenyl-3-aminopropyltrimethoxysilane as the surface treatment agent have the lowest viscosity in the range where the share rate is around 10 to a small value. It was found that the value was sufficiently low even in the range beyond that.

  It was found that the test samples A1 and A5 to A7, in which HMDS was used as the surface treatment agent, had a larger viscosity over the entire share rate than the test samples of Test Examples A2 and A4. In particular, it has been found that the viscosity increases in the vicinity of the shear rate range of 0.1 to 10.

  The viscosity of the test samples of Test Examples A3 and A8 employing 3-glycidoxypropyltrimethoxysilane as the surface treatment agent is slightly higher near the share rate of more than 10, but jumps off as it becomes smaller than 10. It turns out that it grows.

  From the above results, it was found that by using N-phenyl-3-aminopropyltrimethoxysilane as the surface treating agent, a small viscosity can be realized in a wide range of shear rate.

(Evaluation of cohesiveness)
-Preparation of resin composition 80 parts by mass of fused silica (volume average particle size 5 μm), 20 parts by mass of spherical silica (prepared by VMC method: Admafine: volume average particle size 5 μm), silica particles (manufactured by Admatechs; After mixing 0.3 parts by mass of nano silica (YA010C-SP3; volume average particle size 10 nm), coarse particles of 25 μm or more were removed to prepare test samples B1 and B2. The filler composed of fused silica and spherical silica is previously surface-treated with a surface treatment agent (test sample B1 is HMDS, corresponding to test samples A1, A5 to A7, test sample B2 is KBM-573, corresponding to test samples A2 and A4). Processed.

  One of the test samples B1 and B2 was mixed with 25 parts by mass and 16.7 parts by mass of ZX-1059 (Toto Kasei) as a resin material, and then mixed in a planetary mixer (mixing conditions: 2000 rpm, 7 Min), resin compositions B1 and B2 (corresponding to the MUF sealing material of the present invention) of each test example in which the silica content was adjusted to 60% by mass were prepared.

・ Evaluation of cohesiveness
41.7 g of each of the resin compositions B1 and B2 was weighed, mixed with 50 g of methyl ethyl ketone (MEK), and shaken for 1 minute. It was confirmed by visual observation that it was uniformly dissolved. After passing through a sieve having an opening of 25 μm, the resin material adhering to the sieve was washed off with MEK. Thereafter, the entire sieve was dried with a dryer, and the residue on the sieve was collected and its mass was measured.

  As a result, the resin composition B1 was 0.0102 g and the resin composition B2 was 0.0062 g, and the amount of aggregation was about 60.8% based on the resin composition B1. It was found that the treatment with KBM-573 is effective for reducing the cohesiveness.

<Manufacture of silica particles (surface-treated)>
[Test Example 1]
(Manufacture of raw silica particles)
Colloidal silica snowtex OS as an aqueous slurry in which silica particles are dispersed in water as an aqueous medium (silica content 20%: manufactured by Nissan Chemical Co., Ltd .: primary particle size is 10 nm) for 100 parts by mass (surface treatment) Treatment step and drying step).

(Surface treatment process)
(1) Preparatory process 40 mass parts of isopropanol was added to 100 mass parts of aqueous slurry, and the dispersion liquid by which a silica particle was disperse | distributed to the liquid medium was obtained by mixing at room temperature (about 25 degreeC).
(2) First Step 1.82 parts by mass of phenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM103) was added to this dispersion and mixed at 40 ° C. for 72 hours. By this step, the hydroxyl group present on the surface of the silica particles was surface treated with a silane coupling agent. At this time, phenyltrimethoxysilane was calculated and added so that a necessary amount of hydroxyl groups (partially) remained without being surface-treated.
(3) Second Step Next, 3.71 parts by mass of hexamethyldisilazane was added to this mixture and left at 40 ° C. for 72 hours. Through this step, the silica particles were surface-treated to obtain a silica particle material. As the surface treatment progressed, the silica particles that became hydrophobic could no longer exist stably in water and isopropanol, and agglomerated and precipitated. The molar ratio of phenyltrimethoxysilane to mexamethyldisilazane was 2: 5.

(Solidification process)
4.8 parts by mass of 35% aqueous hydrochloric acid solution was added to the mixture obtained in the surface treatment step to precipitate the silica particle material. The precipitate was filtered with a filter paper (5A manufactured by Advantech). The filtration residue (solid content) was washed with pure water and then vacuum-dried at 100 ° C. to obtain a silica particle material solid material (raw material silica particles).

  The obtained silica particles had D10 of 8.8 μm, D50 of 124.5 μm, and D90 of 451.9 μm.

(Crushing process)
A crushing step was performed on the obtained raw material silica particles to obtain silica particles of this test example. The crushing step was carried out under the conditions of a crushing pressure of 0.3 MPa and a supply rate of 10 kg / h using a jet mill (manufactured by Seishin Enterprise Co., Ltd., model number STJ-200). The obtained silica particles had a bulk density of 251.7 g / L, D10 of 0.8 μm, D50 of 1.8 μm, D90 of 4.0 μm, and primary particles having a volume average particle size of 10 nm.

[Test Example 2]
Instead of the crushing step in Test Example 1, what was spray dried by the spray drying method was used as a test sample of this Test Example. Specifically, 100 parts by mass of the raw material silica particles obtained in the solidification step were dispersed in 200 parts by mass of IPA, which was sprayed at a flow rate of 180 ° C. and 5 L / h and dried. The obtained silica particles had a bulk density of 341.3 g / L.

[Test Example 3]
What was obtained in the solidification step without carrying out the crushing step in Test Example 1 was used as the test sample of this Test Example. The obtained silica particles had a bulk density of 769 g / L, D10 of 8.8 μm, D50 of 124.5 μm, D90 of 451.9 μm, and the volume average particle size of the primary particles was 10 nm.

[Test Example 4]
Commercially available silica particles (manufactured by Nippon Aerosil Co., Ltd., AEROSIL R972, so-called Aerosil silica) were used as test samples for this test example. The silica particles of this test example had a bulk density of 41.0 g / L.

[Test Examples 5 to 7]
In the crushing step in Test Example 1, the bulk density was adjusted by adjusting the crushing pressure and the supply amount. The bulk density of the test sample of Test Example 5 was 271.3 g / L, the test sample of Test Example 6 was 364.6 g / L, and the test sample of Test Example 7 was 249.8 g / L. There was a tendency for the bulk density to increase by increasing the crushing pressure. Although detailed results are not shown, it was found that the surface of the metal nitride particles can be coated almost without gaps as in the above test.

Claims (5)

A filler containing fused silica surface-treated with N-phenyl-3-aminopropyltrimethoxysilane and spherical silica prepared by the VMC method in a mass ratio of 100: 0 to 50:50;
Resin material,
A mold underfill encapsulant.   The encapsulant for mold underfill according to claim 1, comprising silica particles having a volume average particle size smaller than that of the fused silica and not less than 5 nm and not more than 300 nm. The silica particles are
The volume average particle size of the primary particles is 300 nm or less, the bulk density is 450 g / L or less,
It has a functional group represented by the formula (1): -OSiX ¹ X ² X ³ and a functional group represented by the formula (2): -OSiY ¹ Y ² Y ³ on the surface. The MUF sealing material according to claim 1 or 2. (In the above formulas (1) and (2); X ¹ is a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group; X ² , X ³ Are independently selected from —OSiR ₃ and —OSiY ⁴ Y ⁵ Y ⁶ ; Y ¹ is R; Y ² and Y ³ are each independently selected from R and —OSiY ⁴ Y ⁵ Y ⁶ .Y ⁴ is an R; ^{Y 5} and ^{Y 6} is selected from R and -OSiR ₃ independently;. R is independently selected from alkyl groups of 1 to 3 carbon atoms Incidentally, ^{X 2} , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ are any of the adjacent functional groups X ² , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ , and —O—. May be combined with each other.) A crushing step of crushing so that the bulk density is 450 g / L or less with respect to the raw material silica particles having a volume average particle size of the primary particles of 300 nm or less,
The silica particles obtained in the crushing step, fused silica having a volume average particle size larger than the primary particles of the silica particles, and spherical silica prepared by the VMC method are used in a mass ratio of 100: 0 to 50:50. A mixing step of mixing the filler and the resin material contained in the range of
Have
At least the filler is surface-treated with N-phenyl-3-aminopropyltrimethoxysilane,
The raw silica particles are
A surface treatment step of surface treatment with a silane coupling agent and an organosilazane in a liquid medium containing water;
Removing the liquid medium;
It is processed in the pretreatment process with
The silane coupling agent has three alkoxy groups, a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group,
The molar ratio of the silane coupling agent to the organosilazane is the silane coupling agent: the organosilazane = 1: 2 to 1:10.
The manufacturing method of the sealing material for mold underfills characterized by the above-mentioned. The surface treatment step includes
A first treatment step of treating with the silane coupling agent;
A second treatment step of treating with the organosilazane,
The method for producing a mold underfill sealing material according to claim 4, wherein the second treatment step is performed after the first treatment step.

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