JPH0841294A - Insulating resin paste and semiconductor apparatus - Google Patents

Abstract

PURPOSE:To provide a semiconductor apparatus excellent in solder cracking resistance, reliability and heat dissipation. CONSTITUTION:Semiconductor devices are mounted on a lead frame by using an insulating resin paste containing an epoxy resin, a curing agent and an inorganic filler, capable of forming a cured material exhibiting <=2X10<-5>/ deg.C linear expansion coefficient and >=35X10<-4>cal/cm.sec deg.C thermal conductivity at 50 to 100 deg.C and sealed by using an epoxy resin composition for sealing of semiconductor containing an epoxy resin, a curing agent and an inorganic filler. This inorganic filler contains (1) alumina particles having >=5mum average particle diameter in an amount of 60 to 100wt.% based on the whole filler and (2) silica particles of <=10mum average particle diameter, spherical crystalline silica particles of >=70mum average particle diameter or mixed silica particles thereof in an amount of 0 to 40wt.% based on the whole filler. In addition, this inorganic filter composed of the above-mentioned components (1) and (2) has a particle size distribution satisfying 0.6 to 0.93 n value of Rosin-Rammlar equation for 1mum particle diameter to the maximum particle diameter and <=0.99 coefficient of correlation of the regression line.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is excellent in low water absorption and low expansion and is an insulating resin paste as a die bond material capable of reducing the defective rate in the soldering process, and excellent in solder crack resistance. , A semiconductor device which is excellent in reliability and heat dissipation and can be widely used for various purposes.

[0002]

2. Description of the Related Art
The miniaturization and speeding up of portable computers and communication devices incorporating integrated circuits are becoming active. Since such high-speed circuits generate heat, they must be sealed with a sealing material with high thermal conductivity and low stress. Therefore, sealing with a ceramic with a low coefficient of linear expansion and high thermal conductivity is necessary. Alternatively, a method of encapsulating a high heat conductive metal such as a copper plate as a heat radiating plate with a low stress type resin encapsulating material has been mainstream.

However, the ceramic encapsulation has a drawback that it is not suitable for general use because the cost is too high, and the use of a heat dissipation plate causes the package to become thick, which makes miniaturization impossible. It was hard to say that it was a simple sealing material.

On the other hand, the step of mounting the semiconductor element on the die pad of the lead frame is an important step that affects the reliability of the semiconductor device.

Conventionally, as the mounting method, there are a eutectic method in which silicon on the back of the element is heated and pressure-bonded to a copper-plated surface on a lead frame, a method using solder, a method using conductive silver paste, and the like. Then, the method of using solder and the method of using conductive silver paste have become the mainstream when the price of copper rises.

However, the method using solder is
It has been pointed out that solder may scatter and cause corrosion of electrodes and the like. In addition, compared with the solder method, the method using conductive silver paste causes element cracks at high temperatures, especially due to the stress generated in the soldering process, or the moisture that enters the silver paste through the encapsulant expands due to steam explosion. However, there is a problem that it causes a crack in the sealing material. Therefore, it is desired to solve the above problems in semiconductor devices.

The present invention has been made in view of the above circumstances, and is an insulating resin for mounting on a lead frame of a semiconductor element, which is excellent in low water absorption and low expansion and can reduce a defective rate in a soldering process. An object of the present invention is to provide a paste and a semiconductor device using the paste, which has excellent solder crack resistance, reliability, and high heat dissipation.

[0008]

Means for Solving the Problems and Actions The inventors of the present invention have made extensive studies in order to achieve the above object, and as a result, the cured product containing an epoxy resin, a curing agent and an inorganic filler is heated to 50 ° C.
Linear expansion coefficient from 2 to 10 ^-5 / ° C or less,
Mounting a semiconductor element on a lead frame using an insulating resin paste having a thermal conductivity of 35 × 10 ⁻⁴ cal / cm · sec · ° C. or higher. In this case, the mounted semiconductor element is made of an epoxy resin composition. In particular, an epoxy resin, a curing agent, and an inorganic filler are contained, and as the inorganic filler, (1) alumina particles having an average particle size of 5 μm or more are contained in an amount of 60 to 100% by weight of the entire filler, and (2) an average particle size. Particle size is less than 10μm or average particle size is 70μ
m or more spherical crystalline silica particles or mixed silica particles thereof in an amount of 0 to 40% by weight based on the total weight of the filler, and having a particle size of 1 μm of the inorganic filler composed of the above (1) and (2)
The n value of the Rosin-Rammler formula from m to the maximum particle size is 0.
By encapsulating with an epoxy resin composition for semiconductor encapsulation that has a particle size distribution of 6 to 0.93 and a regression line correlation coefficient of 0.99 or less, the above problems are solved and high quality is achieved. A semiconductor device can be obtained, and further, as an inorganic filler of the insulating resin paste, (1) spherical alumina particles having an average particle size of 5 μm or more are 60% by weight or more of the entire filler, and (2) average particles. Spherical silica particles having a diameter of 10 μm or less, spherical crystalline silica particles having an average particle diameter of 70 μm or more, or a mixed silica particle thereof is contained in an amount of 40% by weight or less of the entire filler, and is composed of (1) and (2) above. An inorganic filler having a particle size distribution in which the n value of the Rosin-Rammler formula from the particle size of 1 μm to the maximum particle size of the inorganic filler is 0.6 to 0.93, and the correlation coefficient of the regression line is 0.99 or less. Use By, more quality is found to be stable.

That is, the above-mentioned novel insulating resin paste gives a cured product having excellent fluidity, high thermal conductivity, low stress, and low water absorption, and the epoxy resin composition for semiconductor encapsulation. The material has excellent fluidity, high thermal conductivity, low stress, and excellent moldability.By using this resin paste as a mounting material to mount a semiconductor element on a lead frame, In addition to being able to reduce the defect rate in the soldering process, by sealing this semiconductor element with the epoxy resin composition for semiconductor sealing, the obtained semiconductor device has excellent solder crack resistance and high heat dissipation. Therefore, the present invention has been made, and has led to the present invention.

Therefore, the present invention contains an epoxy resin, a curing agent and an inorganic filler, and the cured product is from 50 ° C. to 100 ° C.
Insulation for mounting on a lead frame of a semiconductor device, which has a coefficient of linear expansion up to ℃ 2 × 10 ^-5 / ° C or less and a thermal conductivity of 35 × 10 ^-4 cal / cm · sec · ° C or more Resin paste; As the inorganic filler,
(1) Spherical alumina particles having an average particle size of 5 μm or more account for 60% by weight or more of the entire filler, and (2) the average particle size is 10 μm.
m or less spherical silica particles, or an average particle diameter of 70 μm or more spherical crystalline silica particles or a mixed silica particle thereof in an amount of 40% by weight or less of the entire filler, and (1) above,
The n value of the rosin-Rammler formula from the particle size of 1 μm to the maximum particle size of the inorganic filler composed of (2) is 0.6 to 0.
93, an insulating resin paste using a particle size distribution with a regression line correlation coefficient of 0.99 or less; a semiconductor device in which a semiconductor element is mounted on a lead frame using the resin paste; A semiconductor device sealed with a cured product of an epoxy resin composition; the epoxy resin composition contains an epoxy resin, a curing agent, and an inorganic filler, and the inorganic filler has (1) an average particle size of 5 μm or more. The alumina particles of 60 to 100
%, And (2) silica particles having an average particle size of 10 μm or less, spherical crystalline silica particles having an average particle size of 70 μm or more, or mixed silica particles thereof in an amount of 0 to 40% by weight of the entire filler.
The rosin having a particle size of 1 μm to the maximum particle size of the inorganic filler containing 1% by weight and containing (1) and (2) above.
It is sealed with an epoxy resin composition for semiconductor encapsulation, which uses a Lambler equation having an n value of 0.6 to 0.93 and a regression line correlation coefficient of 0.99 or less. A characteristic semiconductor device is provided.

The present invention will be described in more detail below. In the semiconductor device of the present invention, a semiconductor element is mounted on a lead frame using an insulating resin paste, and this is sealed with an epoxy resin composition for semiconductor encapsulation. It must be stopped.

In this case, as the insulating resin paste,
Contains epoxy resin, curing agent and inorganic filler, and has a linear expansion coefficient of 2 × 10 ⁻⁵ from 50 ° C. to 100 ° C.
/ ° C or less, thermal conductivity is 35 × 10 ^-4 cal / cm · se
Use a material with a temperature of c · ° C or higher.

Here, as the first component epoxy resin, one having two or more epoxy groups in one molecule can be used, and it can be cured by various curing agents as described later. There is no particular limitation on the molecular structure and molecular weight, and various conventionally known compounds can be used. Specifically, for example, an epoxy resin synthesized from various novolak resins including epichlorohydrin and bisphenol, an alicyclic epoxy resin, an epoxy resin having a halogen atom such as chlorine or bromine atom introduced therein can be mentioned. Among these, a glycidyl ether derivative of bisphenol A or bisphenol F is preferably used to obtain a resin paste. In addition,
The above-mentioned epoxy resin is not always necessary for its use.
The use is not limited to two types, and two or more types may be mixed and used.

Further, as the epoxy resin, the softening point of the mixture with the curing agent described below is 30 ° C. or lower and 25
It is more preferable to use a material having a viscosity at 500 ° C. of 500 poise or less.

When using the above epoxy resin,
The monoepoxy compound may be appropriately used in combination. Specific examples of this monoepoxy compound include styrene oxide, cyclohexene oxide, propylene oxide, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, octylene oxide, and dodecene oxide.

Specific examples of the second component curing agent include amine type curing agents represented by diaminodiphenylmethane, diaminophenylsulfone, metaphenylenediamine and the like,
Examples include acid anhydride type curing agents such as phthalic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, and phenol novolac curing agents having two or more hydroxyl groups in one molecule such as phenol novolac and cresol novolac. . Among these, acid anhydride type curing agents are preferably used in order to obtain an epoxy resin composition having a low viscosity and a low stress.

The amount of these curing agents used can be a usual amount, but it is preferably in the range of 50 to 150 equivalent%, particularly 80 to 110 equivalent% with respect to the equivalent of the epoxy groups of the epoxy resin.

Furthermore, in the insulating resin paste according to the present invention, various curing accelerators such as imidazole or its derivatives, tertiary amino derivatives and phosphine derivatives are used for the purpose of promoting the reaction between the epoxy resin and the curing agent. There is no problem with using a cycloamidine derivative or the like in combination. In addition, the compounding amount of these curing accelerators can also be made into the usual range.

Next, the type and blending amount of the third component inorganic filler may be selected so that the cured product of the insulating resin paste according to the present invention has the above-mentioned linear expansion coefficient and thermal conductivity. desirable.

As the inorganic filler, specifically, spherical alumina, crystalline silica, fused silica and the like are preferably used, and spherical alumina is particularly preferably used. In this case, spherical alumina may be blended alone, or crystalline silica, an inorganic filler such as fused silica may be used together with the spherical alumina, if necessary, within a range that does not impair the desired properties such as thermal conductivity. Well, particularly when fused silica is used together, the moisture resistance of the composition can be improved by 2 to 3 times.

In the present invention, as the inorganic filler, 60% by weight or more, particularly 70 to 100% by weight, of spherical alumina particles having an average particle size of 5 μm or more, and 40% by weight of the entire filler are used as the inorganic filler.
A rosin having a particle size of 1 μm to a maximum particle size is contained in an amount of not more than 1% by weight, particularly 0 to 30% by weight of spherical silica particles having an average particle size of 10 μm or less, spherical crystalline silica particles having an average particle size of 70 μm or more, or a mixture thereof. Lambler's n value is 0.6 to 0.93, especially 0.65 to 0.85, and the regression line correlation coefficient is 0.99 or less, especially 0.96 to 0.99.
It is particularly preferred to use those having a particle size distribution of

The method for measuring the particle size distribution of the filler is as follows. (1) Measuring method of average particle size Laser diffraction type particle size distribution measuring device (Cirrus, HR85
It is measured in 0). (2) Method for measuring n value and correlation coefficient of Rosin-Rammler equation The data obtained in (1) above is converted into a Rosin-Rammler diagram by the following Rosin-Rammler equation, and the maximum particle diameter is converted to the particle diameter. A regression line up to 1 μm is drawn, and the slope (n value) of the line and the correlation coefficient of the regression line are calculated. R (Dp) = 100 · exp (−b · Dpn) Dp: Particle size R (Dp): Accumulated weight% from the maximum particle size to Dp n, b: Constant

Since the resin paste containing the above-mentioned inorganic filler is a resin paste having extremely excellent fluidity,
It is possible to increase the filling amount of inorganic filler,
As a result, the cured product is excellent in high thermal conductivity and low stress, and also in low stress and low water absorption, so that solder crack resistance is improved. Inorganic filler that does not meet this condition,
That is, when a resin paste containing spherical alumina particles having an average particle size of less than 5 μm in an amount of 60% by weight or more of the entire inorganic filler or an alumina particle having a non-spherical shape is used, the fluidity becomes insufficient and the filler It may not be possible to increase the filling amount. Further, when the compounding amount of the spherical alumina particles is less than 60% by weight of the whole inorganic filler,
Sufficient thermal conductivity cannot be obtained. Furthermore, the n value of the rosin-Rammler equation from the particle diameter of 1 μm to the maximum particle diameter of the inorganic filler is outside the range of 0.6 to 0.93, or the correlation coefficient of the regression line of the rosin-Rammler equation is 0.99. If it is larger than the above range, the moldability and fluidity are remarkably inadequate, and as a result, a cured product poor in high thermal conductivity and low stress may be provided.

Unlike the fused silica system, the alumina-containing system such as the above-mentioned inorganic filler has a particle size distribution in which the n value of the rosin-Rammler formula is 0.6 to 0.93. When adjusted as described above, the fluidity can be remarkably improved.

Specifically, such an inorganic filler is obtained by first forming various spherical alumina particles having different arbitrary particle size distributions individually or in an arbitrary ratio to obtain spherical alumina particles having an average particle size of 5 μm or more. Spherical silica particles having an average particle size of 10 μm or less, obtained by using the spherical alumina particles alone or in the same manner as the spherical alumina particles, and having an average particle size of 70 μm.
It can be obtained by mixing the above spherical crystalline silica particles in the above proportions to prepare an inorganic filler having a desired optimum particle size distribution. At this time, it is preferable that the slope of the cumulative particle size distribution curve of the inorganic filler does not change abruptly at any point, and a filler exhibiting a rapid change is better than a filler showing no abrupt change. May decrease the fluidity of the resin paste.

In the present invention, the inorganic filler is preferably surface-treated in advance with a coupling agent such as a silane coupling agent or a titanate coupling agent in order to improve low water absorption, thermal shock resistance and crack resistance. . As the coupling agent, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, epoxy silane such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N
-Β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,
It is preferable to use a silane coupling agent such as aminosilane such as N-phenyl-γ-aminopropyltrimethoxysilane and mercaptosilane such as γ-mercaptotrimethoxysilane. Here, the amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited.

The amount of the above-mentioned inorganic filler to be blended is preferably 200 parts or more, more preferably 400 to 800 parts, based on 100 parts (parts by weight, the same applies hereinafter) of the total amount of the epoxy resin and the curing agent.
As the blending amount is increased, a composition having low expansion and low water absorption can be obtained.

In the present invention, carbon functional silanes for improving adhesion, waxes, releasing agents such as fatty acids such as stearic acid and metal salts thereof, pigments such as carbon black, etc., if necessary.
Dyes, antioxidants, surface treatment agents (γ-glycidoxypropyltrimethoxysilane, etc.), various conductive fillers, thixotropy imparting agents, and other additives can be added to the resin paste.

The insulating resin paste of the present invention can be obtained by uniformly stirring and mixing the predetermined amounts of the above-mentioned components (the order of mixing the components is not particularly limited). In this case, the above-mentioned components may be diluted with an organic solvent such as acetone, toluene, xylene, etc., if necessary, but their viscosity (25% when measured at a rotation speed of 4 rpm using a BH type viscometer). Viscosity at 100 ° C) is 100-1
It is preferably 0000 poise, particularly 100 to 5000 poise, more preferably 100 to 3000 poise, and it is preferable to add the above-mentioned essential components and optional components so that the viscosity is in this range.

Further, the above resin paste contains Na and Cl.
The ion concentration is preferably 7 ppm or less, and particularly preferably 4 ppm or less, and when it is more than 7 ppm, it may be difficult to obtain sufficient moisture resistance. The Na and Cl ion concentrations were 10 g of the resin paste and 5 of ion-exchanged water.
It can be measured by putting in 0 ml and extracting at 100 ° C. for 20 hours.

The curing conditions of the insulating resin paste of the present invention can be set, for example, at a curing temperature of 80 to 180 ° C. for 30 to 480 minutes. In addition, in order to suppress the generation of bubbles on the surface and inside when curing, not only one-step heating but also 2
It is also possible to employ a so-called step cure in which the heating temperature is changed more than in stages to perform curing.

The insulating resin paste according to the present invention has a linear expansion coefficient of 2 × from 50 ° C. to 100 ° C.
10 ⁻⁵ / ° C. or less, preferably 1.8 × 10 ⁻⁵ / ° C. or less and a thermal conductivity of 35 × 10 ⁻⁴ cal / cm · sec ·
℃ or more, preferably 50 × 10 ^-4 cal / cm · sec
-It must be above ° C. When the linear expansion coefficient of the cured product is larger than 2 × 10 ^-5 / ° C or the thermal conductivity is 35 × 1
If it is less than 0 ⁻⁴ cal / cm · sec · ° C., good solder crack resistance cannot be obtained, and the object of the present invention cannot be achieved.

In the present invention, when a semiconductor element is mounted on a lead frame with the insulating resin paste,
A usual method can be adopted as a mounting method.

Next, in the present invention, an epoxy resin, a curing agent, and an inorganic filler are indispensable as a sealing resin composition for sealing a semiconductor element mounted on a lead frame using the above-mentioned insulating resin paste. An epoxy resin composition containing as a component is used.

Here, the epoxy resin is not particularly limited in molecular structure, molecular weight and the like as long as it is a compound having at least two epoxy groups in one molecule, and for example, novolac type, bisphenol type and biphenyl type epoxy resins. Examples thereof include epoxy resins such as naphthalene skeleton-containing epoxy resins. As the epoxy resin, these may be used alone or in combination of two or more, but in order to obtain an encapsulating epoxy resin composition highly filled with a filler, a biphenyl type epoxy resin having a low melt viscosity is used. It is particularly preferred to use

The curing agent is not particularly limited in molecular structure, molecular weight, etc., as long as it is a compound having two or more functional groups capable of reacting with an epoxy resin, and examples thereof include novolac type, bisphenol type and biphenyl type phenols. Examples thereof include resins, naphthalene skeleton-containing phenol resins, and curing agents such as amine curing agents. In addition, as a hardening | curing agent, these can be used individually or in mixture of 2 or more types.

The amounts of the above epoxy resin and curing agent are not particularly limited. For example, when a phenol resin is used,
It is preferable that the molar ratio of the phenolic OH groups contained in the curing agent is 0.5 to 1.5 with respect to 1 mol of the epoxy groups contained in the epoxy resin component.

The inorganic filler used in the present invention comprises (1) alumina particles having an average particle size of 5 μm or more in 60% of the total amount of the filler.
To 100% by weight, preferably 70 to 100% by weight, and (2) silica particles having an average particle size of 10 μm or less, or spherical crystalline silica particles having an average particle size of 70 μm or more, or mixed silica particles thereof in 0% of the entire filler. To 40% by weight, preferably 0 to 30% by weight, and above (1), (2)
The n value of the rosin-Rammler formula from the particle size of 1 μm to the maximum particle size of the inorganic filler composed of
Those having a particle size distribution of preferably 0.65 to 0.85 and a regression line correlation coefficient of 0.99 or less, preferably 0.96 to 0.99 are preferable.

The particle size distribution can be measured in the same manner as the particle size distribution measuring method of the inorganic filler in the insulating resin paste.

Since the epoxy resin composition containing the above-mentioned inorganic filler becomes a resin composition which is remarkably excellent in moldability and fluidity, it becomes possible to increase the filling amount of the inorganic filler, and as a result, It gives a cured product with high thermal conductivity and low stress. Inorganic filler that does not meet this condition,
That is, a resin composition containing 60% by weight or more of alumina particles having an average particle size of less than 5 μm with respect to the whole inorganic filler has insufficient moldability and fluidity, and the filler filling amount cannot be increased. Further, when the content of alumina particles is less than 60% by weight of the whole inorganic filler, or when silica is more than 40% by weight of the whole inorganic filler, sufficient thermal conductivity cannot be obtained. Furthermore, the particle size of the inorganic filler is 1
When the n value of the Rosin-Rammler formula from μm to the maximum particle size is outside the range of 0.6 to 0.93 or when the correlation coefficient of the regression line of the rosin-Rammler formula is larger than 0.99, the formability is remarkably increased. However, the fluidity becomes insufficient, and as a result, a cured product having a high thermal conductivity and a low stress is provided.

In the alumina-containing system such as the above-mentioned inorganic filler, unlike the fused silica system, the n-value of the rosin-Rammler formula of the inorganic filler is 0.6 to 0.93 as described above.
The fluidity can be improved remarkably only when the particle size distribution is adjusted to the above range, but in order to obtain a sealing resin composition highly filled with a filler, use spherical alumina and spherical silica. Is particularly preferable.

Specifically, as the above-mentioned inorganic filler, first, various alumina particles having different arbitrary particle size distributions are mixed alone or in an arbitrary ratio to obtain alumina particles having an average particle diameter of 5 μm or more. The alumina particles thus obtained alone or in the same manner as the above-mentioned alumina particles have an average particle size of 1
0 μm or less silica particles and / or spherical crystalline silica particles having an average particle size of 70 μm or more obtained in the same manner as the above alumina particles are mixed at the above ratio to prepare an inorganic filler having the optimum particle size distribution as described above. To do. At this time, it is preferable that the slope of the cumulative particle size distribution curve of the inorganic filler thus obtained does not change suddenly at any point. A filler having a particle size distribution in which the slope of the cumulative particle size distribution shows a sudden change at an arbitrary point may lower the fluidity as compared with a filler having no abrupt change.

In the present invention, the surface treatment of the inorganic filler with a coupling agent such as a silane coupling agent or a titanate coupling agent improves low water absorption, thermal shock resistance and crack resistance. Is preferred. As the coupling agent, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, epoxy silane such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-β- (Aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and other aminosilanes, γ-mercaptotrimethoxysilane and other mercaptosilane and other silane cups It is preferable to use a ring agent. Here, the amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited, and can be usual.

When the above-mentioned inorganic filler of the present invention is filled, a resin composition having excellent moldability and fluidity is obtained, so that the filling amount of the inorganic filler can be increased, and as a result, high thermal conductivity can be obtained. A cured product having excellent properties and low stress can be obtained. Therefore, from this point of view, in order to obtain a cured product having sufficiently high thermal conductivity and low stress, it is desirable that the resin composition contains the inorganic filler in an amount of 85% by weight or more. The thermal conductivity of the encapsulating resin composition is 50 × 10 ⁻⁴ ca
l / cm · sec · ° C or more, preferably 60 × 10 ⁻⁴ c
It is preferably al / cm · sec · ° C or higher. 5
If it is 0 × 10 ⁻⁴ cal / cm · sec · ° C. or less, the thermal resistance of the package becomes large, and it may not be possible to accommodate a device having a large heat generation amount.

In the present invention, it is preferable to use a curing catalyst in order to accelerate the curing reaction between the epoxy resin and the curing agent. The curing catalyst is not particularly limited as long as it accelerates the curing reaction, and examples thereof include triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, triphenylphosphine / triphenylborate, tetraphenyl. Phosphine compounds such as phosphine / tetraphenylborate, triethylamine, benzyldimethylamine, α
-Methylbenzyldimethylamine, tertiary amine compounds such as 1,8-diazabicyclo (5.4.0) undecene-7, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole A compound or the like can be used.

As a general method for preparing the encapsulating epoxy resin composition of the present invention as a molding material, an epoxy resin, a curing agent, the above-mentioned inorganic filler and other additives are blended in a predetermined composition ratio. Then, this can be mixed sufficiently uniformly with a mixer or the like, then melt-mixed with a hot roll, a kneader or the like, cooled and solidified, and then pulverized to an appropriate size to obtain a molding material. The molding material thus obtained can impart excellent characteristics and reliability when used for sealing and covering electronic parts or electric parts such as semiconductor devices.

The semiconductor device of the present invention can be easily manufactured by encapsulating the semiconductor element mounted on the lead frame with the insulating resin paste using the encapsulating epoxy resin composition. Examples of the semiconductor element to be sealed include, but are not particularly limited to, integrated circuits, transistors, thyristors, and diodes. The sealing can be performed by a general method, and a transfer molding method or the like can be adopted. In addition, it is preferable that the epoxy resin composition for sealing is further heated and post-cured after molding, and the post-curing is 150.
It is preferable that the heating is performed at a temperature of not less than 0 ° C.

[0048]

A semiconductor device in which a semiconductor element is mounted on a lead frame with the insulating resin paste of the present invention and further this is encapsulated with a cured product of the epoxy resin composition for semiconductor encapsulation of the present invention is a soldering process. Low defect rate, reliability,
It has excellent heat dissipation and can be widely used for various purposes.

[0049]

EXAMPLES The present invention will be specifically described below by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. All parts in each example are parts by weight. Preparation of resin paste: epoxy resin (epoxy equivalent 18
4 epoxidized bisphenol A) 43.0 parts, acid anhydride (4-methylhexahydrophthalic anhydride) 48.0 parts and the inorganic fillers A to D shown in Table 1 are blended in the amounts shown in Table 1, Further, 3 parts of an imidazole-based curing accelerator HX3741 (manufactured by Asahi Kasei Corp.) and 1 part of γ-glycidoxypropyltrimethoxysilane were added and uniformly mixed to prepare 5 kinds of resin pastes.

Next, the obtained resin paste was heated at 120 ° C. for 1 hour and further heated at 150 ° C. for 2 hours to be cured, and the physical properties of each cured product were evaluated by the following methods. The results are shown in Table 1.
Shown in (A) Viscosity: The viscosity at 25 ° C was measured at a rotation speed of 4 rpm using a BH type rotational viscometer. (B) Linear expansion coefficient: A test piece having a size of 5 × 5 × 15 mm was used to measure the value when the temperature was raised at a rate of 5 ° C. per minute by a dilatometer (measure the value from 50 ° C. to 100 ° C.). ). (C) Thermal conductivity: Shower Denko's Shotherm Q
Using TM-DII rapid thermal conductivity meter, diameter 50 mm x 7
A disk-shaped cured product having a size of mm was measured by the non-constant heat wire method. (D) Water absorption: A disk-shaped cured product having a diameter of 50 mm × 3 mm was placed in a constant temperature and humidity chamber of 85 ° C./85% RH, and 1
The water absorption rate after 00 hours was measured. (E) Extraction purity: 10 g of the resin composition and 50 g of ion-exchanged water
Na and Cl extracted in 100 ml for 20 hours at 100 ° C
The ion concentration (ppm) was measured.

From the results shown in Table 1, it was found that the resin paste according to the present invention has low water absorption, low expansion and high thermal conductivity.

[0052]

[Table 1]

Preparation of epoxy resin composition for encapsulation: The following components were uniformly melt-mixed with a two-roll heat, cooled and pulverized to obtain an epoxy resin composition for semiconductor encapsulation. In addition, Table 1
No. The filler of No. 4 has a particle size distribution which shows the best fluidity in JP-A-4-18445 (4.7% by weight of alumina having an average particle size of 24 μm and an average particle size of 10).
A high thermal conductive filler having a filler containing 81.3% by weight of alumina having a particle size of 81.3% and 14.1% by weight of fine spherical silica having an average particle size of 1 μm) is used. Composition: Epoxy resin 54.5 parts (Yuka-Shepepoxy Co., YX-4000H, epoxy equivalent 190 g / mol) Phenolic resin 24.3 parts (Mitsui Toatsu Chemicals, Millex XL-225, hydroxyl equivalent 168 g / mol) ) Phenolic resin 15.0 parts (Showa Kasei Co., MEH7710, hydroxyl equivalent 137 g / mol) Brominated epoxy resin 6.2 parts (Asa Chiba Co., AER755, epoxy equivalent 459 g / mol) Inorganic filler shown in Table 2 Amount shown in Table 2 Curing catalyst (triphenylphosphine) 1.5 parts Antimony trioxide 8.0 parts Coloring agent (Mitsubishi carbon black) 1.5 parts Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2 0.0 parts Release agent (carnauba wax) 1.0 parts

[0054]

[Table 2]

Next, regarding the obtained composition, the following (f) to
The test of (h) was conducted. The results are shown in Table 3. (F) Spiral flow value 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the conditions of g / cm ² and molding time of 120 seconds. (G) Thermal conductivity 175 ° C., 70 kg / cm ² , molding time 120 seconds.
A 0 mm x 6 mm test piece was inserted in a sandwich shape between the upper heater and the calorimeter and the lower heater, and was brought into constant contact with air pressure, and the temperature difference between both surfaces of the test piece after reaching a steady state at 50 ° C, The thermal conductance was automatically calculated from the calorimeter output, and the thermal conductivity was determined from the product of the value of this thermal conductance and the thickness of the test piece. (H) Package evaluation Using the insulating resin paste shown in Table 1, a semiconductor element having a chip size of 10 × 8 × 0.3 mm and a chip generation amount of 2.5 w is placed on a 152-pin QFP (copper lead frame).
After mounting under conditions of 50 ° C. for 2 hours and wire bonding, the epoxy resin composition for encapsulation obtained in Synthesis Example 2 was used for 1
It sealed under the condition of 75 ° C./2 minutes. After the molded package was post-cured at 180 ° C. for 5 hours, the following evaluations were performed. (H-1) Package thermal resistance: Using the device obtained in the example, the thermal resistance was measured by operating the device at a wind speed of 1.0 m / s. The thermal resistance was calculated from (Tj-Ta) / heat value of chip. Tj: Chip temperature Ta: Atmosphere temperature (C-2) Formability: The appearance of the obtained package was inspected and the occurrence of voids was observed. (C-3) Reflow crack resistance: Package is 85 ° C
After being left in an atmosphere of / 85% RH for 72 hours to perform a moisture absorption treatment, the following test was performed. (A) The number of external cracks in the encapsulant when put in a paper phase reflow furnace at 215 ° C. for 90 seconds was examined (n = 2).
0). (B) After putting the paper phase reflow furnace at 215 ° C. for 90 seconds, the number of external cracks of the sealing material was examined after repeating the temperature cycle of −55 ° C., 30 minutes to 150 ° C., 30 minutes for 200 times ( n = 20).

From the above results, the present invention, which uses the novel resin paste according to the present invention as a mount material, has high thermal conductivity as a sealing material, and has low stress, moldability and fluidity, is obtained. By using the related epoxy resin composition for semiconductor encapsulation, the defect rate in the soldering process is reduced,
It was confirmed that a semiconductor device excellent in reliability and heat dissipation could be obtained.

[0057]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01L 23/31 (72) Inventor Kazuo Dobashi 1 Hitomi, Izumi, Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Industrial Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Toshio Shiobara 1 Hitomi, Osamu Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd.

Claims (5)

． 0 [Claims] 1. A cured product containing an epoxy resin, a curing agent, and an inorganic filler, having a linear expansion coefficient from 50 ° C. to 100 ° C. of 2 × 10 ⁻⁵ / ° C. or less and a thermal conductivity of 35 × 10 ^−4. ca
Insulating resin paste for mounting on a lead frame of a semiconductor element, which is 1 / cm · sec · ° C. or higher. 2. As the inorganic filler, (1) spherical alumina particles having an average particle size of 5 μm or more are 60% by weight or more of the entire filler, and (2) spherical silica particles or average particles having an average particle size of 10 μm or less. Spherical crystalline silica particles having a diameter of 70 μm or more, or mixed silica particles thereof, are used in an amount of 40
The n value of the rosin-Rammler formula from the particle size of 1 μm to the maximum particle size of the inorganic filler containing 0.6% by weight or less and the regression line is 0.6 to 0.93. The insulating resin paste according to claim 1, wherein an inorganic filler having a particle size distribution with a correlation coefficient of 0.99 or less is used. 3. A semiconductor device in which a semiconductor element is mounted on a lead frame by using the insulating resin paste according to claim 1. 4. The semiconductor device according to claim 3, wherein the semiconductor element is sealed with a cured product of an epoxy resin composition. 5. The epoxy resin composition is an epoxy resin,
A hardening agent and an inorganic filler are contained, and as the inorganic filler, (1) alumina particles having an average particle size of 5 μm or more are 60 to 100% by weight of the whole filler, and (2) an average particle size is 10
0-40% by weight of the total filler of silica particles having a particle size of less than or equal to μm, spherical crystalline silica particles with an average particle size of 70 μm or more, or mixed silica particles thereof, and (1) above,
The n value of the rosin-Rammler formula from the particle size of 1 μm to the maximum particle size of the inorganic filler composed of (2) is 0.6 to 0.
93. The semiconductor device according to claim 4, wherein the correlation coefficient of the regression line 93 is 0.99 or less.