JP6331570B2 - Underfill material, electronic component sealed with underfill material, and manufacturing method thereof - Google Patents

Description

  The present invention relates to an underfill material particularly suitable for a flip chip type semiconductor device, an electronic component such as a flip chip type semiconductor device sealed with this composition, and a method for manufacturing the same.

  Conventionally, in the field of element sealing of electronic component devices such as transistors and ICs, resin sealing has been the mainstream in terms of productivity and cost, and epoxy resin compositions have been widely used. This is because the epoxy resin is balanced in various properties such as workability, moldability, electrical properties, moisture resistance, heat resistance, mechanical properties, and adhesiveness with inserts. Liquid resin compositions for electronic components are widely used as sealing materials in semiconductor devices mounted on bare chips such as COB (Chip on Board), COG (Chip on Glass), and TCP (Tape Carrier Package). Further, in a semiconductor device (flip chip) in which a semiconductor element is directly bump-connected to a wiring board using ceramic, glass / epoxy resin, glass / imide resin or polyimide film as a substrate, the bump-connected semiconductor element and wiring board A liquid resin composition for electronic parts is used as an underfill material for filling the gap. These liquid resin compositions for electronic parts play an important role in protecting electronic parts from temperature and humidity and mechanical external force.

  When flip chip mounting is performed, the thermal expansion coefficient differs between the element and the substrate, so that thermal stress is generated at the joint, and ensuring connection reliability is an important issue. In addition, since the circuit formation surface of the bare chip is not sufficiently protected, it is an important issue to ensure moisture resistance reliability because moisture and ionic impurities are likely to enter. In addition, a fillet is formed on the side surface of the chip to protect the chip, but the thermal stress caused by the difference in thermal expansion between the underfill material and the chip may cause the resin to crack and in the worst case, destroy the chip. is there. Depending on the selection of the underfill material, the joint may not be sufficiently protected when subjected to repeated thermal shocks in a temperature cycle test or the like, and the joint may be fatigued at low cycles. Further, if voids are present in the underfill material, the bumps are not sufficiently protected, and the joint portion may be similarly fatigued at low cycles.

  In order to provide an epoxy resin composition for sealing excellent in moisture-resistant adhesive strength and low stress resistance, and an electronic component device having high reliability (moisture resistance and thermal shock resistance) provided with an element sealed thereby ( A) an epoxy resin, (B) an amine curing agent, (C) a filler, (D) a core shell rubber, (E) a semiconductor resin encapsulant containing a reactive diluent, and this semiconductor resin encapsulant An electronic component device having a sealed element is disclosed (for example, see Patent Document 1).

  To reduce thermal stress, which is one of the above technical issues, by mixing a large amount of inorganic filler in the underfill material, the underfill material, the semiconductor chip, the substrate, the bump, and the linear expansion integer are brought closer to each other. Is effective. However, underfill materials that are highly filled with such inorganic fillers are excellent in the stress characteristics as described above, but the viscosity increases due to the high filling of the inorganic fillers and enters the gap between the semiconductor chip and the substrate. (Penetration) speed is remarkably reduced and productivity tends to be very poor. Moreover, there is a concern that a void is generated due to an increase in viscosity when filling the underfill material.

  On the other hand, the use of a diluent is an effective method for reducing the viscosity of the resin composition. Diluents used for such purposes can be divided into non-reactive and reactive. As the non-reactive diluent, an organic solvent such as toluene or methyl ethyl ketone is used, but these organic solvents have a low boiling point. Therefore, if an attempt is made to lower the viscosity of the underfill material using a non-reactive diluent, there is a risk of causing voids.

  The reactive diluent has a reactive group in the molecule, for example, an epoxy group, so that it reacts with the curing agent and becomes a part of the cured product. There are many relatively few things. Typical examples of the reactive diluent include various monoepoxy compounds and glycidyl ether compounds of polyhydric alcohols, which are also exemplified in Patent Document 1.

  However, when these reactive diluents are used, the glass transition temperature (Tg) and toughness of the cured product of the underfill material tend to be reduced. This problem cannot be solved by simply using the reactive diluent. It is difficult to solve the point, and improvement is desired.

JP 2012-162585 A

  The chip size has increased with the recent high integration and multi-functionalization of semiconductor chips, while the bumps have been reduced in size, pitch and narrow gap due to the increase in the number of pins. When underfilling a narrow gap, for example, a gap of 50 μm or less, voids are likely to occur. In addition, the chip thickness has been reduced with the miniaturization of the mounted equipment, and it has become increasingly difficult to ensure high reliability (humidity resistance, temperature cycle resistance) of semiconductor devices due to the reduction in chip thickness. It is coming.

  The present invention has been made in view of such circumstances, has good fluidity in a narrow gap (for example, a gap of 50 μm or less), has a high penetration rate, and generates voids during molding. An object of the present invention is to provide an underfill material that can be suppressed, and a flip-chip type semiconductor device that is sealed thereby and has high reliability (moisture resistance and temperature cycle resistance).

The present invention is an underfill material used for an electronic component, which includes (A) an epoxy resin, (B) a curing agent, (C) an inorganic filler, and (C) an average particle diameter and content of the inorganic filler The present invention relates to an underfill material having an amount of less than 5 μm and 67% by mass or more and less than 85% by mass of the entire underfill material, and a viscosity at 110 ° C. of 0.2 Pa · s or less. By setting the inorganic filler to a blending amount of 67% by mass or more and less than 85% by mass of the entire underfill material, an electronic component having high reliability (moisture resistance and temperature cycle resistance) can be obtained. By setting the inorganic filler within the above range, it is considered that the linear expansion coefficient of the underfill material can be lowered to the same level as that of the peripheral member such as a semiconductor chip, and as a result, the stress can be relaxed. Furthermore, by setting the viscosity at 110 ° C. to 0.2 Pa · s or less, the penetration speed can be increased even if the gap between the semiconductor element and the wiring board is reduced to 50 μm or less, so the penetration time is shortened. And generation of voids can be suppressed.
The present invention further relates to the underfill material having a viscosity at 90 to 120 ° C. of 0.2 Pa · s or less. By setting the viscosity at 90 to 120 ° C. to 0.2 Pa · s or less, not only can the permeation time be shortened and the generation of voids can be sufficiently suppressed, but the process window ( Windows) can be widened.
In addition, the present invention can reduce stress by reducing the linear expansion coefficient of the underfill material, shorten the permeation time, and reduce the generation of voids by setting the content of the (C) inorganic filler to 70 to 80% by mass. It becomes easier to achieve at the same time.
The present invention also includes a reactive epoxy resin having a viscosity at 25 ° C. of 60 mPa · s or less for reducing the viscosity of the underfill material and increasing the reliability of the semiconductor device sealed with the underfill material. A liquid aromatic amine curing agent may be used as a curing agent for the epoxy resin.
Moreover, this invention relates to the said underfill material which contains either the inorganic filler which has a peak between 0.1-1 micrometer and 1-2 micrometers respectively, and the particle size distribution of the said (C) component simultaneously. By using an inorganic filler having this particle size distribution, an increase in viscosity due to the amount of the inorganic filler can be sufficiently suppressed, even when the gap between the semiconductor element and the wiring board is as narrow as 25 μm or less. A low-viscosity underfill material in which generation of voids is suppressed can be obtained.
Moreover, this invention relates to the said underfill material whose average particle diameter of the said (C) component is less than 1.6 micrometers. Thereby, it can be set as the underfill material which was excellent in the filling property to a narrow gap, and suppressed generation | occurrence | production of a void.
Further, according to the present invention, when the underfill material is measured with a thermogravimetric measuring device (TGA), the weight reduction rate after being left at a predetermined temperature for a predetermined time according to the curing condition of the underfill material is It is related with the said underfill material which is 5% or less. Thereby, generation | occurrence | production of a void can be suppressed more fully.
The present invention also relates to an electronic component sealed with the underfill material.
In addition, the present invention provides a method for manufacturing an electronic component in which the underfill material is sealed by a dispensing method, a casting method, or a printing method, and particularly in a flip chip type semiconductor device having a narrow gap, a dispensing method. The present invention relates to a method for manufacturing an electronic component to be sealed.

  The present invention has an excellent fluidity in a narrow gap (for example, a gap of 50 μm or less), a high penetration rate, and an underfill material that suppresses generation of voids during molding, and sealing by this It is possible to provide a flip-chip type semiconductor device with high reliability (moisture resistance and temperature cycle resistance).

  The present invention is an underfill material used for an electronic component, which includes (A) an epoxy resin, (B) a curing agent, (C) an inorganic filler, and (C) an average particle diameter and content of the inorganic filler The present invention relates to an underfill material having an amount of less than 5 μm and 67% by mass or more and less than 85% by mass of the entire underfill material, and a viscosity at 110 ° C. of 0.2 Pa · s or less. By adopting the above configuration, the underfill material with excellent reliability (moisture resistance and temperature cycle resistance), short permeation time, and no voids, and the gap (gap) between the semiconductor element and the wiring board is 50 μm or less. A highly reliable flip chip type semiconductor device can be provided. The reason for this is as follows.

  The underfill material of the present invention can reduce the thermal expansion coefficient by containing a large amount of silica, and can relieve stress by bringing the linear expansion coefficient close to the semiconductor chip, the wiring board, and the bumps for joining the two. Therefore, an electronic component with high reliability (moisture resistance and temperature cycle resistance) can be obtained. The linear expansion coefficients of semiconductor chips, wiring boards and bumps are generally in the range of 6 ppm / ° C., 7 to 20 ppm / ° C. and 15 to 24 ppm / ° C., respectively. By setting the expansion coefficient to less than 25 ppm / ° C., high reliability of the semiconductor device can be achieved. In order to realize this linear expansion coefficient, it is necessary that the inorganic filler contains 67% by mass or more of the entire underfill material. Furthermore, since the reliability of the semiconductor device can be further improved by setting the linear expansion coefficient of the underfill material to 20 ppm / ° C. or less, the content of the inorganic filler is 70% by mass or more of the entire underfill material. Preferably there is.

  On the other hand, in the present invention as an underfill material, the viscosity at 110 ° C. is 0.2 Pa · s or less. Thereby, the permeability and fluidity into the narrow gap are improved and the penetration speed can be increased, so that the penetration time can be shortened and the generation of voids can be suppressed. Here, from the viewpoint of shortening the impregnation time by increasing the permeation rate, the viscosity at 110 ° C. is preferably 0.15 Pa · s or less. Furthermore, when the emphasis is on improving workability by shortening the impregnation time of the underfill material (for example, 100 seconds or less at 110 ° C.), the viscosity at 110 ° C. is 0.10 Pa · s or less. It is more preferable. The lower limit is preferably 0.05 Pa · s or more from the viewpoint of suppressing the generation of voids, and more preferably 0.08 Pa · s or more in order to enhance the effect of suppressing the generation of voids.

  In addition, the viscosity of 90 to 120 ° C. increases the working temperature range when the underfill material is infiltrated and filled by paying attention not only to the viscosity at 110 ° C. but also the viscosity at 90 to 120 ° C. Is preferably 0.2 Pa · s or less. Thereby, the permeation time can be further shortened, and generation of voids can be sufficiently suppressed. From the viewpoint of shortening the impregnation time by increasing the permeation rate as in the case of 110 ° C., the viscosity at 90 to 120 ° C. is more preferably 0.15 Pa · s or less, and 0.10 Pa · It is particularly preferred that it is s or less. The lower limit of the viscosity is also preferably 0.05 Pa · s or more at 90 to 120 ° C. from the viewpoint of suppressing the generation of voids.

  The underfill material of the present invention has a viscosity at 110 ° C., or a viscosity in the range of 90 to 120 ° C. in order to widen the process window, and the permeability and fluidity of the liquid resin composition for electronic components in the present invention. Use as a guide. Focusing on the viscosity of 110 ° C., preferably 90 to 120 ° C., is the highest temperature that can be practically employed when injecting the liquid resin composition into the fine gap in the production of flip chip semiconductor devices. In electronic parts having a gap between the semiconductor element and the substrate of 100 μm or less, particularly a narrower gap of 50 μm or less, and a narrower 25 μm or less, the voids are sufficiently suppressed and the filling is performed quickly and reliably. This is because the physical property value most reflects the permeability and fluidity of a possible underfill material. In the flip semiconductor device, the narrowing of the gap between the semiconductor element and the wiring board is progressing, and an underfill material that can be used for narrowing the gap of 50 μm or less is strongly demanded. In order to fully meet this requirement, the present invention is characterized in that the physical property value reflecting the fluidity of the underfill material is noted and the physical property value is defined.

  The viscosity specified above is measured at a temperature of 90 to 120 ° C. using a rheometer AR2000 (TA instrument) under the conditions of a 40 mm parallel plate and a shear rate of 32.5 (1 / s).

In the present invention, in addition to the viscosity measurement method using a rheometer, measurement is performed when an E-type rotational viscometer is rotated at a predetermined temperature for 1 minute at a predetermined rotation speed (rpm, 1/60 sec ⁻¹ ). A value obtained by multiplying the value by a predetermined conversion factor may be defined and defined as the viscosity. The measured value is obtained by using an E-type rotational viscometer equipped with a cone rotor having a cone angle of 3 ° and a cone radius of 10 mm for a liquid maintained at a predetermined temperature ± 1 ° C. The rotation speed and the conversion factor differ depending on the viscosity of the liquid to be measured. Specifically, the viscosity of the liquid to be measured is roughly estimated in advance, and the rotation speed and the conversion coefficient are determined according to the estimated value. When the estimated value of the viscosity of the liquid to be measured is 0 to 1.25 Pa · s, the rotational speed is 100 rpm, the conversion factor is 0.0125, and when the estimated value of the viscosity is 1.25 to 2.5 Pa · s. When the rotational speed is 50 rpm, the conversion coefficient is 0.025, and the estimated viscosity value is 2.5 to 6.25 Pa · s, the rotational speed is 20 rpm, the conversion coefficient is 0.0625, and the estimated viscosity value is 6. In the case of 25 to 12.5 Pa · s, the rotation speed is 10 rpm and the conversion coefficient is 0.125. Here, since the absolute value of the viscosity measured by the E-type rotational viscometer is not the same as the viscosity measured by the rheometer, the viscosity of the underfill material according to the present invention is defined by converting to the viscosity measured by the rheometer. can do.

  The underfill material of the present invention has a viscosity of 110 ° C., preferably a viscosity of 90 to 120 ° C., which is not higher than 0.2 Pa · s in order to increase the permeation rate and to suppress void generation during permeation. (C) As an inorganic filler, an average particle diameter is less than 5 micrometers, and it is necessary to make the content less than 85 mass%. When the average particle size is 5 μm or more, not only the generation of voids becomes significant, but it becomes difficult to completely penetrate the underfill material into a narrow gap of 50 μm or less due to aggregation of the inorganic filler. In addition, when the inorganic filler having an average particle size of less than 5 μm is contained in an amount of 85% by mass or more with respect to the entire underfill material, the viscosity at a temperature of 90 to 120 ° C. is obtained even when the particle size of the inorganic filler is optimized. It cannot be made 0.2 Pa · s or less, and the permeability of the underfill material is greatly reduced. In particular, a semiconductor device having a narrow gap of 50 μm or less has a problem that the underfill material cannot be filled and sealed to the end of the semiconductor element regardless of the permeation time. Furthermore, the content of the inorganic filler having an average particle size of less than 5 μm makes the semiconductor device more reliable by forming a uniform fillet at the peripheral edge of the semiconductor element when the underfill material is infiltrated. From the viewpoint of achieving, it is preferably 80% by mass or less.

  The underfill material of the present invention can be applied to a semiconductor device having a gap of 50 μm or less. Furthermore, for a semiconductor device having a narrow gap of 25 μm or less, (C) the average particle size of the inorganic filler is 2 μm or less. Preferably, it is less than 1.6 μm. However, the viscosity of the underfill material tends to lower the fluidity and permeability of the underfill material as the average particle size of the inorganic filler decreases to a few microns or less.

  Therefore, optimization of the composition that can improve the fluidity and permeability of the underfill material while reducing the average particle size of the inorganic filler to less than 1.6 μm was investigated. As a result, it is preferable to use at least one of inorganic fillers each having a peak between 0.1 to 1 μm and 1 to 2 μm in the particle size distribution. Further, by including both, a narrow gap of 25 μm or less is used. It has been found that an underfill material that can be applied to a semiconductor device having the above can be obtained. In addition, about the range of an average particle diameter and content, it mentions later in detail with the kind of inorganic filler used suitably by this invention.

  In the present invention, as a prescription for reducing the viscosity of the underfill material, the composition contained in the epoxy resin composition is a low-viscosity epoxy resin, specifically, a liquid having a viscosity at 25 ° C. of 60 mPa · s or less. It is preferable to contain this epoxy resin as a diluent. The low-viscosity liquid epoxy resin contained here is a bifunctional compound containing an alkylene group or an ether group in order to suppress the decrease in the glass transition temperature of the underfill material and to keep the heat resistance by reducing the decrease in heating weight. It is more preferable to include an aliphatic epoxy resin that is higher than or equal to the nature of the resin.

  As another method for reducing the viscosity of the underfill material, an unreactive solvent may be used. However, when the content of the solvent is large, when a semiconductor device having a gap of 50 μm or less, particularly 25 μm or less is sealed, voids become prominent and the reliability of the semiconductor device is seriously deteriorated. It was. This problem occurs not only in the solvent, but also in the case where there are volatile low-molecular-weight impurity components already contained in the resin composition and volatile decomposition products produced during thermal curing of the underfill material. . As a result of investigation based on this idea, the weight reduction rate after being left at a predetermined temperature for a predetermined time in accordance with the curing conditions of the underfill material is the amount of voids generated in the sealed portion filled with the underfill material. It was found to correlate with the degree. Therefore, in the present invention, the heating weight reduction rate of the underfill material is defined as a physical quantity that can predict the generation of voids. When the underfill material of the present invention is applied to a semiconductor device having a narrow gap of 25 μm or less, the weight reduction rate of the underfill material is preferably 5% or less when measured with a thermogravimetric apparatus (TGA). .

  Each component contained in the underfill material of the present invention will be described below.

[(A) Epoxy resin]
The underfill material includes (A) an epoxy resin. The (A) epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule, and generally used epoxy resins can be used without particular limitation.

  If the underfill material is liquid at room temperature as a whole, the epoxy resin itself may be either solid or liquid at room temperature, or both may be used in combination. Among these, an epoxy resin that is liquid at room temperature is preferable from the viewpoint of lowering the viscosity of the underfill material. In this specification, “liquid at room temperature” means a state in which fluidity is exhibited at 25 ° C. Further, in the present specification, “liquid” means a substance that exhibits fluidity and viscosity and has a viscosity of 0.0001 Pa · s to 10 Pa · s at 25 ° C. as a measure of viscosity.

  Examples of epoxy resins that can be used in the present invention include phenols and aldehydes typified by diglycidyl ether type epoxy resins such as bisphenol A, bisphenol F, bisphenol AD, bisphenol S, hydrogenated bisphenol A, and orthocresol novolac type epoxy resins. Reaction of epichlorohydrin with epoxidized novolak resin, glycidyl ester type epoxy resin obtained by reaction of polybasic acid such as phthalic acid and dimer acid and epichlorohydrin, p-aminophenol, diaminodiphenylmethane, isocyanuric acid and the like Glycidylamine-type epoxy resins obtained by oxidation, linear aliphatic epoxy resins obtained by oxidizing olefinic bonds with peracids such as peracetic acid, and alicyclic epoxy resins. May be used in combination or two or more kinds thereof may be used in. Among them, diglycidyl ether type epoxy resins and glycidyl amine type epoxy resins are preferable from the viewpoints of viscosity, actual use and material price, and liquid bisphenol type epoxy resins are preferable from the viewpoint of fluidity. From the viewpoints of heat resistance, adhesiveness and fluidity, liquid glycidylamine type epoxy resins are preferred.

  The above two types of epoxy resins may be used alone or in combination of two or more, but the blending amount is matched to the total amount of the liquid epoxy resin in order to exhibit its performance. It is preferably 20% by weight or more, more preferably 30% by weight or more, and further preferably 50% by weight or more. There is no restriction | limiting in particular as an upper limit, From a viewpoint, such as a viscosity, a glass transition temperature, and heat resistance, it can determine in the range from which a desired property and characteristic are acquired.

  In addition, the underfill material of the present invention can be used in combination with a solid epoxy resin as long as the effect of the present invention is achieved, but the solid epoxy resin used in combination from the viewpoint of fluidity during molding is an epoxy. The content is preferably 20% by weight or less based on the total amount of the resin. Furthermore, the purity of these epoxy resins, particularly the amount of hydrolyzable chlorine, is preferably less because it involves corrosion of aluminum wiring on ICs and other elements, and in order to obtain an underfill material with excellent moisture resistance, it should be 500 ppm or less. Is preferred. Here, the amount of hydrolyzable chlorine is a value obtained by dissolving 1 g of an epoxy resin of a sample in 30 ml of dioxane, adding 5 ml of a 1N-KOH methanol solution and refluxing for 30 minutes, and then obtaining by potentiometric titration. is there.

[(B) Curing agent]
As the curing agent of the component (B) used in the present invention, a generally used curing agent for epoxy resin can be used without particular limitation. Among these, an aromatic amine is preferable from the viewpoint of excellent temperature cycle resistance and moisture resistance, and the reliability of the semiconductor device can be improved, and an aromatic amine that is liquid at room temperature is more preferable. Examples of the amine having a liquid aromatic ring at room temperature include diethyltoluenediamine, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,6-diaminobenzene, 3,3′-diethyl-4,4′-diaminodiphenylmethane, 3,5,3 ′, 5′-tetramethyl-4,4′-diaminodiphenylmethane , dimethylthiotoluenediamine, and the like. These liquid aromatic amine compounds are commercially available products such as JER Cure W (Japan Epoxy Resin Co., Ltd., trade name), Kayahard AA, Kayahard AB, Kayahard AS (Nippon Kayaku Co., Ltd., trade name). ), Totoamine HM-205 (Toto Kasei Co., Ltd., trade name), Adeka Hardener EH-101 (ADEKA Corporation, trade name), Epomic Q-640, Epomic Q-643 (Mitsui Chemicals, trade name), DETDA80 (Lonza, trade name) and the like are available, and these may be used alone or in combination of two or more.

  Among these, from the viewpoint of storage stability, 3,3′-diethyl-4,4′-diaminodiphenylmethane, ethyltoluenediamine and dimethylthiotoluenediamine are preferable, and the curing agent is mainly composed of any one of these or a mixture thereof. It is preferable that Examples of diethyltoluenediamine include 3,5-diethyltoluene-2,4-diamine and 3,5-diethyltoluene-2,6-diamine, and these may be used alone or as a mixture. Those containing 60% by weight or more of 3,5-diethyltoluene-2,4-diamine are preferred.

  Moreover, in the underfill material of the present invention, in addition to the amine-based curing agent containing the above liquid aromatic amine, a commonly used curing agent such as a phenolic curing agent or an acid anhydride can be used in combination. A solid curing agent can also be used in combination. Among them, an amine-based curing agent containing a liquid aromatic amine compound has the most excellent effect for increasing the reliability of a semiconductor device.

  The compounding amount of the curing agent is not particularly limited as to the equivalent ratio of the epoxy resin containing the component (A) and the curing agent containing the component (B), but in order to keep each unreacted component small, The curing agent is preferably set in the range of 0.7 equivalents to 1.6 equivalents, more preferably 0.8 equivalents to 1.4 equivalents, and even more preferably 0.9 equivalents to 1.2 equivalents.

[(C) Inorganic filler]
The inorganic filler of component (C) used in the present invention includes silica such as spherical silica and crystalline silica, alumina such as calcium carbonate, clay and alumina, silicon nitride, silicon carbide, boron nitride, calcium silicate and titanium. Examples thereof include powders such as potassium acid, aluminum nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, and titania, or beads and glass fibers formed by spheroidizing them. Furthermore, examples of the inorganic filler having a flame retardant effect include aluminum hydroxide, magnesium hydroxide, zinc borate, and zinc molybdate. These inorganic fillers may be used alone or in combination of two or more. Among these, silica is preferable from the viewpoint of easy availability, chemical stability, and material cost, and spherical silica is particularly preferably used from the viewpoint of fluidity and permeability into the fine gaps of the underfill material. Examples of the spherical silica include silica obtained by a deflagration method and fused silica. Moreover, the surface of the inorganic filler in the present invention may be surface-treated or may be surface-treated using a silane coupling agent described later.

  The average particle size of the inorganic filler in the present invention is preferably less than 5 μm as outlined above. Thereby, it can be set as the underfill material excellent in the filling property to a narrow gap. In particular, for a semiconductor device having a narrow gap of 50 μm or less, the average particle size of the inorganic filler is preferably 2 μm or less. Particularly, in a semiconductor device having a narrower gap of 25 μm or less, the average particle size is less than 1.6 μm. It is more preferable that

  In the present invention, the “average particle size” of the inorganic filler means that the cumulative distribution is 50% in the cumulative distribution represented by the cumulative frequency, where the particle size is class and the volume is frequency using the following method. It means particle diameter (volume average particle diameter). As a method of measuring the particle size of the inorganic filler, for example, a method of measuring a large number of particles simultaneously using a device such as laser diffraction, dynamic light scattering, small angle X-ray scattering, a transmission electron microscope, scanning electron Examples thereof include a method of imaging using a microscope, an atomic force microscope, etc., and measuring the particle diameter of each particle. Using a method such as liquid phase centrifugation, field flow fractionation, particle size exclusion chromatography, fluid dynamics chromatography or the like, a pretreatment for separating particles of 100 μm or more may be performed before measuring the particles. Moreover, when a measurement sample is the hardened | cured material of an underfill material, the ash obtained as a residue after processing at high temperature of 800 degreeC or more with a muffle furnace etc. can be measured by said method.

  The compounding quantity of the inorganic filler in this invention is 67 mass% or more and less than 85 mass% of the whole underfill material. As a result, not only can void generation in the underfill material after filling and curing be reduced, but also the linear expansion coefficient can be reduced to the same level as that of peripheral members such as semiconductor chips, and stress can be relaxed. An electronic component having high reliability (moisture resistance and temperature cycle resistance) can be obtained. Above all, in order to increase the permeability of the underfill material from the viewpoint of further improving the reliability of the semiconductor device by forming a uniform fillet at the peripheral edge of the semiconductor element when the underfill material is infiltrated The content of the inorganic filler having an average particle size of less than 5 μm is preferably 80% by mass or less. Further, since the reliability of the semiconductor device is further improved by further reducing the linear expansion coefficient of the underfill material, the content of the inorganic filler is 70% by mass or more of the entire underfill material. It is preferable.

  In addition, as described above, the (C) inorganic filler in the present invention is preferably 2 μm or less, more preferably less than 1.6 μm. It is preferable to include at least one of an inorganic filler having a peak between 1 μm and an inorganic filler having a peak between 1 and 2 μm. By adopting the above configuration, since aggregation of the inorganic filler can be suppressed, the semiconductor device having a narrow gap can be easily filled and sealed, and an increase in the viscosity of the underfill material due to the inorganic filler is suppressed. Therefore, good penetrability into a semiconductor device having a narrow gap can be realized.

  Furthermore, in order to improve the fluidity and permeability of the underfill material while reducing the average particle size of the inorganic filler to less than 1.6 μm, the particle size distribution is between 0.1 and 1 μm, respectively. By including both of the inorganic fillers having a peak, an underfill material applicable to a semiconductor device having a narrow gap of 25 μm or less can be obtained. When both inorganic fillers are used in combination, (inorganic filler having a peak at 0.1 to 1 μm) / (inorganic filler having a peak at 1 to 2 μm) = 1/99 to 30/70. A blending ratio is preferred. When the blending ratio of both is 1/99 or more and 30/70 or less, a favorable viscosity reduction effect can be obtained.

  As described above, in the present invention, it is preferable to use at least one of the inorganic fillers having a peak between 0.1 to 1 μm and 1 to 2 μm, and more preferably to use both in combination. An increase in viscosity due to the amount of the material can be sufficiently suppressed, and a low-viscosity underfill material can be obtained.

[(D) Epoxy resin having a viscosity at 25 ° C. of 60 mPa · s or less]
The (D) epoxy resin having a viscosity at 25 ° C. of 60 mPa · s or less used in the present invention usually has the same action as the reactive diluent used to reduce the viscosity of the liquid epoxy resin composition. Here, the viscosity at 25 ° C. is a value measured with an E-type viscometer as described above. (D) The epoxy resin has an epoxy group in the molecule, and reacts with the curing agent to be incorporated into the structure of the underfill cured product. For example, alkyl monoglycidyl ether or alkylphenol monocrisydyl ether Monoepoxy compounds such as polyglycols and glycidyl ether compounds of polyhydric alcohols can be used. When the viscosity at 25 ° C. is 60 mPa · s or less, the effect of lowering the viscosity of the underfill material can be expected, and problems such as a decrease in glass transition temperature and a decrease in toughness of the cured resin occur. Hateful.

  In the present invention, (D) among epoxy resins having a viscosity at 25 ° C. of 60 mPa · s or less, it is preferable to use a bifunctional or higher aliphatic epoxy resin containing an alkylene group or an ether group. Since these epoxy resins contain two or more glycidyl ether groups in one molecule, they form a three-dimensional cross-link at the time of curing, and can not only suppress a decrease in glass transition temperature, but also toughen the resin cured product. Have advantages. Bifunctional or higher aliphatic epoxy resins containing an alkylene group or an ether group include polyvalent polyhydrides such as alkyl diglycidyl ethers such as polyethylene glycol diglycidyl ether and polypropylene diglycidyl ether, and 1,6-hexanediol diglycidyl ether. And diglycidyl ether of alcohol. These epoxy resins, like other epoxy resins, are preferably high-purity ones having a hydrolyzable chlorine content of 500 ppm or less from the viewpoint of improving the moisture resistance reliability of the semiconductor device.

  The blending amount of these (D) epoxy resins having a viscosity at 25 ° C. of 60 mPa · s or less is preferably 5 to 40% by mass, and more preferably 10 to 30% by mass when the total amount of the epoxy resin is 100 parts by mass. By setting the blending amount to 5% by mass or more, it is possible to expect a lower viscosity of the underfill material, and by setting it to 40% by mass or less, there is a problem of a decrease in glass transition temperature and toughness of the cured resin product. Is less likely to occur.

[Other ingredients]
Various flexible agents can be blended with the underfill material of the present invention from the viewpoint of improving thermal shock resistance and reducing stress on the semiconductor element. The flexible agent is not particularly limited, but rubber particles are preferable. Examples thereof include styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), butadiene rubber (BR), urethane rubber (UR), and acrylic. Examples thereof include rubber particles such as rubber (AR). Among these, rubber particles made of acrylic rubber are preferable from the viewpoint of heat resistance and moisture resistance, and core-shell type acrylic polymers, that is, core-shell type acrylic rubber particles are more preferable.

  Silicone rubber particles can also be suitably used as the rubber particles other than those described above. For example, silicones obtained by crosslinking polyorganosiloxanes such as linear polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, etc. Examples thereof include rubber particles, those obtained by coating the surface of silicone rubber particles with a silicone resin, and core-shell polymer particles comprising a core of solid silicone particles obtained by emulsion polymerization or the like and a shell of an organic polymer such as an acrylic resin. The shape of these silicone polymer particles can be used regardless of whether they are amorphous or spherical, but it is preferable to use a spherical one in order to keep the viscosity related to the moldability of the underfill material low. . These silicone polymer particles are commercially available from Toray Dow Corning Silicone Co., Ltd. and Shin-Etsu Chemical Co., Ltd.

  Further, a silicone-modified epoxy resin can be added as a surfactant. The silicone-modified epoxy resin can be obtained as a reaction product of an organosiloxane having a functional group that reacts with an epoxy group and an epoxy resin, but is preferably liquid at room temperature. Examples of organosiloxanes having functional groups that react with epoxy groups are dimethylsiloxane, diphenylsiloxane, methylphenyl having at least one amino group, carboxyl group, hydroxyl group, phenolic hydroxyl group, mercapto group, etc. in one molecule. Examples thereof include siloxane. The weight average molecular weight of the organosiloxane is preferably in the range of 500 or more and 5000 or less. The reason for this is that if it is less than 500, the compatibility with the resin system becomes too good and the effect as an additive is not exhibited, and if it exceeds 5000, it becomes incompatible with the resin system. This is because exudation occurs and the adhesiveness and appearance are impaired. The epoxy resin for obtaining the silicone-modified epoxy resin is not particularly limited as long as it is compatible with the resin system of the underfill material, and an epoxy resin generally used in a liquid resin composition for electronic parts may be used. For example, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, naphthalene diol, hydrogenated bisphenol A, etc. and phenols such as glycidyl ether type epoxy resin and orthocresol novolac type epoxy resin obtained by reaction of epichlorohydrin with Epoxy epoxidized novolak resin obtained by condensation or co-condensation with aldehydes, glycidyl ester epoxy obtained by reaction of polybasic acids such as phthalic acid and dimer acid with epichlorohydrin Glycidylamine type epoxy resin obtained by reaction of polyamine such as fat, diaminodiphenylmethane, isocyanuric acid and epichlorohydrin, linear aliphatic epoxy resin obtained by oxidizing olefin bond with peracid such as peracetic acid, alicyclic epoxy resin These may be used alone, or two or more of these may be used in combination, but those at room temperature are preferred.

  The addition amount of the surfactant is preferably 0.01% by weight or more and 1.5% by weight or less, and more preferably 0.05% by weight or more and 1% by weight or less with respect to the entire underfill material. When the amount is less than 0.01% by weight, a sufficient effect of addition cannot be obtained.

  In the underfill material of the present invention, a curing accelerator that accelerates the reaction of the liquid epoxy resin of the component (A) and the curing agent containing the component (B) can be used as necessary. There are no particular limitations on the curing accelerator, and conventionally known ones can be used. For example, 1,8-diaza-bicyclo (5,4,0) undecene-7,1,5-diaza- Cycloamidine compounds such as bicyclo (4,3,0) nonene, 5,6-dibutylamino-1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine , Tertiary amine compounds such as dimethylaminoethanol, tris (dimethylaminomethyl) phenol, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl- 2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5 Dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6- (2′-methylimidazolyl- (1 ′))-ethyl-s-triazine, 2-heptadecylimidazole Imidazole compounds such as tributylphosphine, dialkylarylphosphine such as dimethylphenylphosphine, alkyldiarylphosphine such as methyldiphenylphosphine, organic phosphines such as triphenylphosphine, alkyl group-substituted triphenylphosphine, and the like Compounds include maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5 A quinone compound such as til-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone and phenyl-1,4-benzoquinone, and a compound having a π bond such as diazophenylmethane and phenol resin are added. Examples thereof include compounds having intramolecular polarization, and derivatives thereof, and further, phenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate, and the like. One kind may be used alone, or two or more kinds may be used in combination. Moreover, as a curing accelerator having a potential, core-shell particles formed by coating a shell having a normal temperature solid amino group as a core and a shell of a normal temperature solid epoxy compound can be cited. Amicure (Ajinomoto Co., Inc.) is commercially available. Company, product name), Novacure (Asahi Kasei Chemicals Co., Ltd., trade name) in which a microencapsulated amine is dispersed in a bisphenol A type epoxy resin or a bisphenol F type epoxy resin can be used.

  The blending amount of the curing accelerator is not particularly limited as long as the curing accelerating effect is achieved, but (A) 0.1 wt% or more and 40 wt% or less is preferable with respect to the liquid epoxy resin, More preferably, it is 1 to 20% by weight. If it is less than 0.1% by weight, it tends to be inferior in curability in a short time, and if it exceeds 40% by weight, the curing rate is too fast and it becomes difficult to control, and the storage stability such as pot life and shell life is inferior. Tend to.

  If necessary, a coupling agent can be used for the underfill material of the present invention for the purpose of strengthening the interfacial adhesion between the resin and the inorganic filler or between the resin and the component of the electronic component. These coupling agents are not particularly limited and conventionally known ones can be used. For example, silane compounds having primary and / or secondary and / or tertiary amino groups, epoxy silane, mercaptosilane, Examples thereof include various silane compounds such as alkyl silane, ureido silane, and vinyl silane, titanium compounds, aluminum chelates, and aluminum / zirconium compounds. Examples of these are vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycol. Sidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyl Triethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, γ- (N, N-dimethyl) aminopropyltrimethoxy Silane, γ- (N, N-diethyl) aminopropyltrimethoxysilane, γ- (N, N-dibutyl) aminopropyltrimethoxysilane, γ- (N-methyl) anilinopropyltrimethoxysilane, γ- (N -Ethyl) anilinopropyltrimethoxysilane, γ- (N, N-dimethyl) aminopropyltriethoxysilane, γ- (N, N-diethyl) aminopropyltriethoxysilane, γ- (N, N-dibutyl) amino Propyltriethoxysilane, γ- (N-methyl) anilinopropyltriethoxysilane, γ- (N-ethyl) anilinopropyltriethoxysilane, γ- (N, N-dimethyl) aminopropylmethyldimethoxysilane, γ- (N, N-diethyl) aminopropylmethyldimethoxysilane, γ- (N, N-dibutyl) aminopropy Rumethyldimethoxysilane, γ- (N-methyl) anilinopropylmethyldimethoxysilane, γ- (N-ethyl) anilinopropylmethyldimethoxysilane, N- (trimethoxysilylpropyl) ethylenediamine, N- (dimethoxymethylsilylisopropyl) ) Silane coupling agents such as ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, isopropyl Triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetraoctane Rubis (ditridecylphosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, Isopropyltrioctanoyl titanate, isopropyldimethacrylisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropylisostearoyl diacryl titanate, isopropyltri (dioctylphosphate) titanate, isopropyltricumylphenyl titanate, tetraisopropylbis (dioctylphosphite) titanate And titanate coupling agents such as A seed may be used independently or may be used in combination of 2 or more types.

In addition, in the underfill material of the present invention, if necessary, an ion trap agent represented by the following composition formula (V) (VI) can be used to improve the migration resistance, moisture resistance, and high temperature storage characteristics of semiconductor elements such as ICs. From the viewpoint of making it possible to contain.
Mg _1-x Al _x (OH) ₂ (CO ₃ ) _{x / 2} · mH ₂ O (V)
(0 <X ≦ 0.5, m is a positive number)
BiO _x (OH) _y (NO ₃ ) ₂ (VI)
(0.9 ≦ x ≦ 1.1, 0.6 ≦ y ≦ 0.8, 0.2 ≦ z ≦ 0.4)

The addition amount of these ion trapping agents is preferably 0.1% by weight or more and 3.0% by weight or less, more preferably 0.3% by weight or more and 1.5% by weight or less. The average particle size of the ion trapping agent is preferably 0.1 μm or more and 3.0 μm or less, and the maximum particle size is preferably 10 μm or less. In addition, the compound of the said formula (V) is available as a brand name DHT-4A of Kyowa Chemical Industry Co. , Ltd. as a commercial item. The compound of the above formula (VI) is commercially available as IXE500 (Toagosei Co., Ltd., trade name). Further, other anion exchangers can be added as necessary. There is no restriction | limiting in particular as an anion exchanger, A conventionally well-known thing can be used. Examples thereof include hydrated oxides of elements selected from magnesium, aluminum, titanium, zirconium, antimony, and the like, and these can be used alone or in combination of two or more.

  In the underfill material of the present invention, as other additives, coloring agents such as dyes and carbon black, diluents such as solvents, leveling agents, antifoaming agents, and the like can be blended as necessary.

  When the above-mentioned various additives contained in the underfill material of the present invention generate a volatile component at the time of curing, generation of voids becomes significant when sealing a semiconductor device having a narrow gap of 50 μm or less, particularly 25 μm or less. Therefore, a decrease in the reliability of the semiconductor device becomes a big problem. In particular, the solvent blended to reduce the viscosity of the underfill material is highly volatile and is one of the main causes of void generation. Therefore, as described above, paying attention to the heating weight reduction rate of the underfill material as a physical quantity that can predict the occurrence of voids, the semiconductor device having a narrow gap with the weight reduction rate of the underfill material of 50 μm or less, particularly 25 μm or less. When it is applied to, it is preferably 5% or less when measured with a thermogravimetric apparatus (TGA). Here, the weight reduction rate measured by the thermogravimetric measuring device (TGA) is a value after being allowed to stand at a predetermined temperature for a predetermined time in accordance with the curing condition of the underfill material. In the present invention, as shown in the following examples, for example, when 150 ° C. for 2 hours is adopted as the curing condition for the underfill material, the value measured under that condition is defined as the weight reduction rate.

  The underfill material of the present invention can be prepared by any method as long as the above various components can be uniformly dispersed and mixed. However, as a general method, a predetermined amount of components are weighed, It can be obtained by mixing, kneading using a mixing roll, a planetary mixer or the like, and defoaming as necessary.

  Examples of a method for sealing an element using the underfill material of the present invention include a dispensing method, a casting method, a printing method, and the like.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.

  The test methods of the characteristic tests performed in the examples and comparative examples are summarized below. In addition, various characteristics of the used underfill material, impregnation time, observation of voids, and evaluation of various reliability were performed by the following methods and conditions. The specifications of the semiconductor device used for the reliability evaluation are as follows: chip size 20 × 20 × 0.55 tmm (circuit: daisy chain connection of aluminum, passivation: polyimide film HD4000, product name manufactured by Hitachi Chemical DuPont Microsystems), bump: Solder balls (Sn—Ag—Cu, Φ80 μm, 7,744 pin), bump pitch: 190 μm, substrate: FR-5 (solder resist SR7200, trade name of Hitachi Chemical Co., Ltd., 60 × 60 × 0.8 tmm), chip / Gap between substrates: 50 μm. The test was also conducted on 25 μm where the chip / substrate gap was narrower than 50 μm. The gap of 25 μm is obtained by forming a copper (Cu) pillar in the wiring portion of the semiconductor element and bonding it to the wiring board with solder or gold-gold.

The semiconductor device was manufactured by underfilling an underfill material by a dispense method and curing at 150 ° C. for 2 hours. The curing conditions for various test pieces were also the same.
(1) Viscosity The viscosity of the underfill material at 25 ° C. was measured using an E-type viscometer (cone angle 3 °, rotation speed 5 rpm). Moreover, the viscosity at 30-140 degreeC of the underfill material measured the viscosity in each temperature by 40 mm parallel plate and shear rate 32.5 (1 / s) using AR2000 (TA instrument).
(2) Weight reduction rate After about 10 mg of the underfill material is mounted in a sample container of a TA-2950 type thermobalance (TA instrument) which is a thermogravimetric measuring device, the weight reduction rate after being left at 150 ° C. for 2 hours. Was measured. This weight loss rate was expressed in% as the ratio of weight loss to initial weight.
(3) Impregnation time The semiconductor device is placed on a hot plate heated to 110 ° C., and a predetermined amount of underfill material is dropped on the side surface (one side) of the chip using a dispenser, and the resin composition is placed on the side surface facing the resin composition. The time until penetration was measured.
(4) Void Observation The inside of a semiconductor device produced by underfilling an underfill material was observed with an ultrasonic flaw detector AT-5500 (Hitachi Construction Machinery Co., Ltd.) to examine the presence or absence of voids.
(5) Thermal cycle resistance The semiconductor device produced by underfilling the underfill material is treated for 2000 cycles at a heat cycle of −55 ° C. to 125 ° C. for 30 minutes each, and a continuity test is performed every 1000 cycles to obtain aluminum wiring and The disconnection defect of the pad was examined and evaluated by the number of defective packages / number of evaluation packages.
(6) Moisture resistance reliability After the semiconductor device manufactured by underfilling the underfill material for 200 hours under the HAST condition of 130 ° C. and 85% RH, the presence or absence of disconnection of the aluminum wiring and the pad is confirmed by the continuity test, and the defective package Evaluation was performed by number / number of evaluation packages.
(7) Measurement of average particle diameter The average particle diameter of the inorganic filler was measured as follows.
(7-1) Preparation of sample An inorganic filler was added to a solvent (water) at 5% by mass, and the mixture was vibrated with an ultrasonic homogenizer for 30 minutes and dispersed to prepare a sample.
(7-2) Measurement The measurement was performed with a laser diffraction / scattering particle size distribution analyzer LA-920 (Horiba, Ltd., trade name). The measurement conditions were such that the dispersion medium had a refractive index of 1.00 (in the case of water) and the inorganic filler had a refractive index of 1.47 (in the case of silica particles).
(7-3) Calculation of average particle diameter The particle diameter at an integrated value of 50% (volume basis) in the particle size distribution was taken as the average particle diameter.
(8) The silica used in the measurement underfill material of peak silica were mixed at the same rate as formulation, a particle size distribution was measured using LA-920 type laser diffraction / scattering particle size distribution analyzer (HORIBA). The peak in the particle size distribution indicates the apex.

(Examples 1-16, Comparative Examples 1-6)
As a liquid epoxy resin, a liquid diepoxy resin having 160 epoxy equivalent obtained by epoxidizing bisphenol F (liquid epoxy 1), a trifunctional liquid epoxy resin having 95 epoxy equivalent obtained by epoxidizing aminophenol (liquid epoxy 2), epoxy Equivalent epoxy resin 3 (trade name YED216D of Mitsubishi Chemical Corporation, viscosity at 25 ° C .: 10 to 16 mPa · s), diethyltoluenediamine (liquid amine 1) of active hydrogen equivalent 45 as a curing agent, active hydrogen equivalent of 63 Diethyl-diamino-diphenylmethane (liquid amine 2), acid anhydride of active hydrogen 117 (trade name YH306 from Mitsubishi Chemical Corporation), phenolic curing agent of active hydrogen 140 (trade name MEH8000H from Meiwa Kasei Co., Ltd.), inorganic filling Material 1 average particle size 1.6μm, ratio table Spherical silica product 3.5 m ² / g, an average particle diameter of 0.6μm as an inorganic filler 2, a specific surface area of 6.0 m ² / g of spherical silica, average particle size 3.0μm as the inorganic filler 3, a specific surface area 1 As spherical silica of 0.0 m ² / g and inorganic filler 4, spherical silica having an average particle diameter of 5 μm and a specific surface area of about 0.5 m ² / g was used.

  In addition, 2-phenyl-4-methyl-hydroxyimidazole as a curing accelerator, ethylene glycol ethyl ether as a solvent, and the surface of dimethyl type solid silicone rubber particles as a flexibilizer were modified with an epoxy group, average particle diameter of 2 μm Spherical silicone particles, γ-glycidoxypropyltrimethoxysilane as a silane coupling agent, carbon black as a colorant (trade name: MA-100, manufactured by Mitsubishi Chemical Corporation), bismuth ion trapping agent (Dongguan as an ion trapping agent) A product name IXE-500) of Synthetic Co., Ltd. was prepared. In addition, the compounding quantity of a solvent is represented by the mass% when the whole underfill material containing a solvent is 100 mass parts.

  After blending with the compositions shown in Table 1, Table 2 and Table 3 below, and kneading and dispersing with a three roll and vacuum crusher, Examples 1-16 and Comparative Examples 1-6 Liquid Resin Composition for Electronic Components A product was made. In the table, the blending unit is parts by weight, and the blank represents no blending. In addition, among the inorganic fillers in the table, those having a 0.1-1 μm peak or 1-2 μm peak are indicated by (◯), and those not having are indicated by (×).

  About each underfill material produced by the composition shown in the above Table 1, Table 2 and Table 3, the viscosity, the weight reduction rate and the evaluation result by the semiconductor device are shown in the following Table 4, Table 5 and Table 6, respectively.

  As shown in Tables 4 and 5, Examples 1 to 16 are excellent in various reliability because no void is generated during molding when the gap between the semiconductor element and the wiring board is 50 μm. On the other hand, as shown in Table 6, in Comparative Examples 1 to 3 containing 65% by mass of the inorganic filler, not only the generation of voids during molding is observed, but also the reliability is significantly lowered. Further, in Comparative Example 4 in which the content of the inorganic filler was 85% by mass, the viscosity at 110 ° C. was high, and the underfill material could not be filled between the chip and the substrate. Even in the case where the content of the inorganic filler is 75% by mass, Comparative Example 5 in which the viscosity at 110 ° C. is 0.36 Pa · s is similarly high in the viscosity at 110 ° C. The filling material could not be filled. Furthermore, in Comparative Example 6 containing an inorganic filler having an average particle diameter of 5 μm, although the content of the inorganic filler is 70% by mass, since the particle diameter is large, voids are generated during molding. Various reliability of the equipment was also slightly reduced.

  Thus, the underfill material of the present invention needs to regulate the content of the inorganic filler to 67% by mass or more and less than 85% by mass. Furthermore, as shown in Table 4 (Examples 2 to 8) and Table 5, by setting the content of the inorganic filler in the range of 70 to 80% by mass, both permeability and various reliability of the semiconductor device are achieved. The balance can be improved. In addition, the underfill material of the present invention needs to reduce the viscosity at 110 ° C. to 0 or 2 Pa · s or less, and includes a low-viscosity liquid epoxy resin that acts as a reactive diluent as one of the methods. Is preferred.

  In Examples of the present invention, Examples 1 to 8 include both inorganic fillers having a particle size distribution of 0.1 to 1 μm and a peak between 1 to 2 μm, and therefore a gap between the semiconductor element and the wiring board. In both 50 μm and 25 μm, generation of voids during molding was not observed. In contrast, an underfill material that does not contain both inorganic fillers having a peak between 0.1 to 1 μm and 1 to 2 μm at the same time can suppress the generation of voids at a gap of 50 μm, but is narrower than 25 μm. In the gap, void generation was observed (Examples 9 to 16). Among them, Examples 11 to 13 are underfill materials each independently containing either an inorganic filler having a peak between 0.1 to 1 μm or 1 to 2 μm, and the average particle diameter is 1.6 μm. Although it was as small as the following, the effect of suppressing the generation of voids did not sufficiently appear in a narrow gap of 25 μm. Details of the cause are unknown, but when the flow distribution is narrowed, the particle size of the inorganic filler becomes uniform and the amount of resin existing between the particles increases, so the inorganic filler and the resin are integrated and flow. I think that the function to do is less likely to be expressed, and the probability of voids has increased.

  Moreover, when Example 4 and Examples 15 and 16 are compared, if the weight reduction rate by the thermobalance exceeds 5% by mass, the amount of volatilization is large even if the type and amount of each component of the underfill material are optimized. Therefore, it can be seen that void generation is not suppressed in a narrow gap of 25 μm, and the reliability of the semiconductor device tends to decrease. Therefore, the underfill material of the present invention preferably has a weight reduction rate of 5% or less after being left at a predetermined temperature for a predetermined time according to curing conditions.

  Further, in Table 4, when Examples 4 and 5 are compared with Examples 6 and 7, the curing agent used for the epoxy resin-based underfill material is a liquid aromatic amine compound, an acid anhydride or a phenolic resin curing agent. It can be seen that the temperature cycle reliability of the semiconductor device can be improved. Therefore, in the present invention, it is preferable to use a liquid aromatic amine curing agent when priority is given to increasing the reliability of the semiconductor device.

  As described above, the underfill material of the present invention has good fluidity in a narrow gap, has a high penetration rate, and can suppress the generation of voids during molding. Furthermore, the flip chip type semiconductor device sealed with the underfill material of the present invention can improve various reliability such as moisture resistance and temperature cycle resistance. In addition, the underfill material of the present invention can be used as an underfill material or a sealing material for not only flip-chip type semiconductor devices but also other semiconductor devices, so that its usefulness is extremely high.

Claims (12)

(A) An epoxy resin, (B) a curing agent, (C) an inorganic filler, and the average particle size and content of the (C) inorganic filler are less than 5 μm and 67% by mass or more of the entire underfill material, respectively. The particle size distribution of the inorganic filler (C) has a peak at 0.1 to 1 μm and 1 to 2 μm, respectively, and the viscosity at 110 ° C. is 0.2 Pa · s or less. Underfill material.   Furthermore, the underfill material of Claim 1 whose viscosity in 90-120 degreeC is 0.2 Pa.s or less.   The underfill material according to claim 1 or 2, wherein the content of the (C) inorganic filler is 70 to 80% by mass.   The underfill material according to claim 1, wherein the (A) epoxy resin includes (D) an epoxy resin having a viscosity at 25 ° C. of 60 mPa · s or less.   The underfill material according to claim 4, comprising (D) a bifunctional or higher aliphatic epoxy resin containing an alkylene group or an ether group as an epoxy resin having a viscosity at 25 ° C of 60 mPa · s or less.   The underfill material according to any one of claims 1 to 5, wherein the (B) curing agent is a liquid aromatic amine curing agent. The underfill material as described in any one of Claims 1-6 whose average particle diameter of the said (C) component is less than 1.6 micrometers. The underfill material has a weight loss rate of 5% or less when measured with a thermogravimetric apparatus (TGA) after being allowed to stand at a predetermined temperature for a predetermined time according to the curing conditions of the underfill material. The underfill material according to any one of claims 1 to 7 . Electronic component sealed with underfill material according to any one of 請 Motomeko 1-8. 請 Motomeko dispensing system underfill material according to any one of 1-8, to seal the electronic component by casting method or printing method, a method of manufacturing an electronic component. A method for manufacturing an electronic component in which a gap (gap) between a semiconductor element and a wiring board is 50 μm or less, wherein the underfill material is filled in the gap by a dispensing method to seal the electronic component. 10. A method for producing an electronic component according to 10 . A method of manufacturing an electronic component in which a gap (gap) between a semiconductor element and a wiring board is 25 μm or less, wherein the gap is filled with the underfill material to seal the electronic component. 11. A method for producing an electronic component according to item 11 .