JP2600258B2 - Resin composition for semiconductor encapsulation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition for sealing a semiconductor device. More specifically, the present invention relates to a resin composition for semiconductor encapsulation in which a crack is not generated in an encapsulating resin in a soldering step when a resin-encapsulated semiconductor device is mounted.

<Related Art> In recent years, the degree of integration of semiconductor devices has been rapidly increased, and the size of elements and the miniaturization of wiring have been significantly advanced. Most semiconductor devices, including these highly integrated semiconductor devices, are currently resin-sealed, but this largely depends on the development of a highly reliable sealing resin having excellent performance.

On the other hand, recently, the density and automation of component mounting on printed circuit boards have been increasing, and instead of the conventional "insertion mounting method" in which lead pins are inserted into holes in the board, components are soldered on the board surface. “Surface mounting method” is becoming more and more popular. Along with that, the package is also a conventional DIP
(Dual in-line package) type is shifting to thin FPP (flat plastic package) type suitable for high-density mounting and surface mounting.

With the shift to the surface mounting method, the soldering process, which has not been a problem so far, has become a major problem. In the conventional pin insertion mounting method, the lead portion is only partially heated in the soldering process, but in the surface mounting method, the entire package is immersed in a heating medium and heated. As a soldering method in the surface mounting method, a solder bath immersion, heating with a saturated vapor of an inert gas (a vapor phase method), an infrared reflow method, and the like are used. In any case, the entire package is heated to a high temperature of 210 to 270 ° C. It will be heated. Therefore, the conventional package sealed with the sealing resin has a problem that cracks occur in the resin portion at the time of soldering and cannot be used as a product.

It is said that the cracks generated during the soldering process are caused by the moisture absorbed between the post-curing and the mounting process explosively turning into steam and expanding during soldering and heating. A method has been used in which a package that has been completely dried and stored in a sealed container is shipped.

Various studies have been made on improvements in the sealing resin. For example,
A method of blending a rubber component into a sealing resin to reduce the internal stress (Japanese Patent Application Laid-Open Nos. 58-219218 and 59-96122) and a method of selecting the type of inorganic filler (Japanese Patent Application Laid-Open No. −19
136, JP-A-60-202145), a method of uniformizing stress and strain by making the shape of the inorganic filler spherical or controlling the particle size (JP-A-60-171750).
Japanese Patent Application Laid-Open No. 60-65037), a method of reducing the water absorption by a water-repellent additive or wax to reduce the occurrence of stress due to moisture in a solder bath (Japanese Patent Application Laid-Open No. 60-65023).
and so on.

<Problems to be Solved by the Invention> However, the method of enclosing the dry package in a container has a drawback that the manufacturing process and the handling of the product are complicated, and the product price is extremely high.

In addition, resins improved by various methods are gradually improving their effects, but they are not enough to respond to the more severe requirements accompanying the progress of packaging technology. Specifically, after humidifying a semiconductor device that has been satired with the resin obtained by these conventional methods, for example, 85 ° C./85% RH treatment for 72 hours, or 121 ° C./2 atm PCT (pressure cooker test) When immersed in a solder bath 72 hours after the treatment, any swelling or cracking occurs in the resin portion. In other words, a sufficiently satisfactory encapsulating resin that has prevented cracking during soldering heating has not yet been obtained, and development of an encapsulating resin with excellent solder heat resistance corresponding to the progress of surface mounting technology has been desired. It is the present situation.

An object of the present invention is to provide an improved encapsulating resin that has solved the problem of cracks generated in the soldering step, and to provide a resin-encapsulated semiconductor device that can be surface-mounted.

<Means for Solving the Problems> That is, the present invention provides an epoxy resin (A) and a curing agent (B).
And a resin composition for semiconductor encapsulation containing a powder filler (C) as a main component, wherein the resin composition for semiconductor encapsulation has three or more adjacent hydroxyl groups on an aromatic ring and is other than the hydroxyl group. Compound (D) with or without a substituent of
And a resin composition for semiconductor encapsulation, wherein the powdery filler (C) contains 50% by weight or more of fine powder particles having a particle diameter of 14 μ or less, and the use thereof. Semiconductor device in which the semiconductor element is sealed by

 Hereinafter, the configuration of the present invention will be described in detail.

The resin composition for semiconductor encapsulation of the present invention contains an epoxy resin (A), a curing agent (B) and a powdery filler (C) as main components.

The epoxy resin (A) in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule.

For example, cresol nopolak epoxy resin, phenol novolak epoxy resin, 4,4′-bis (2,3
-Epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenyl and other bishydroxybiphenyl type epoxy resins bisphenol A type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin ,
Examples include a halogenated epoxy resin and a spiro ring-containing epoxy resin.

 Two or more of these epoxy resins may be used in combination.

The amount of the epoxy resin (A) in the resin composition of the present invention is not particularly limited, but is usually 3 to 30% by weight, preferably 5 to 25% by weight.

The curing agent (B) in the present invention is not particularly limited as long as it is cured by reacting with the epoxy resin. For example, a phenol novolak resin, a cresol novolak resin, a novolak resin represented by the following formula (III), (However, n represents an integer of 0 or more.) Various novolak resins synthesized from bisphenol A and resorcinol, various polyhydric phenol compounds, acid anhydrides such as maleic anhydride, phthalic anhydride, and pyromellitic anhydride, and meta Examples include aromatic amines such as phenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone, but are not particularly limited.

The amount of the curing agent (B) in the resin composition of the present invention is not particularly limited, but is usually 1 to 20% by weight, preferably 2 to 15% by weight.

The epoxy resin (A) and the curing agent (B) used in the present invention are those from which sodium ions, chloride ions, free acids, alkalis and impurities which may generate them are removed as much as possible from the viewpoint of moisture resistance. Is preferred.

The mixing ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of the curing agent to the epoxy resin is in the range of 0.5 to 1.5, particularly 0.7 to 1.3 from the viewpoint of mechanical properties and heat resistance. preferable.

The powdery filler (C) in the resin composition of the present invention has a particle size of 14 µ or less, preferably 12 µ or less, particularly preferably.
It is essential to contain fine powder particles of 10 μm or less in an amount of 50% by weight or more. When the amount of fine powder particles having a particle size of 14 μ or less is less than 50% by weight, the effect of preventing the occurrence of cracks in the soldering process is not sufficiently exhibited.

There is no particular limitation on the material of the powdery filler (C), but usually, fused silica, crystalline silica, alumina, silicon nitride, silicon carbide, magnesium carbonate, calcium carbonate, clay, talc, calcium silicate, titanium oxide, etc. Is used. These can be used in combination of two or more. Among them, fused silica is preferably used because it has a large effect of lowering the coefficient of linear expansion and is effective in reducing stress.
There is no particular limitation on the particle shape of the powdery filler (C), and usually, crushed, spherical or a combination of crushed and spherical can be used.

There is no particular limitation on the particle size distribution of the powdery filler (C) as long as the particle size is within the above range. Two or more powdered fillers having different particle size distributions can be used in combination.

In the resin composition of the present invention, the compounding amount of the powdery filler (C) is usually 50 to 85% by weight, preferably 65 to 80% by weight.
It is. If it is less than 50% by weight, the coefficient of linear expansion increases,
If the amount is more than 10% by weight, the moldability is insufficient.

The resin composition for semiconductor encapsulation of the present invention comprises a compound (D) having three or more adjacent hydroxyl groups on an aromatic ring and having or not having a substituent other than the hydroxyl group (hereinafter, compound (D) ) Is essential. When the compound (D) is not contained, the effect of the present invention is not sufficiently exhibited. Examples of the compound (D) include pyrogallol, gallic acid, and derivatives thereof.
Among them, pyrogallol, gallic acid and gallic acid ester are preferably used. Examples of preferably used gallic acid esters include methyl gallate, ethyl gallate, propyl gallate, butyl gallate, pentyl gallate,
Examples include gallic acid esters esterified with alcohols having 6 or less carbon atoms such as hexyl gallate, and particularly esterified with alcohols having 4 or less carbon atoms such as methyl gallate, ethyl gallate, propyl gallate and butyl gallate. Gallic esters exert an even more pronounced effect.
Two or more of these compounds (D) may be used in combination. The compounding amount of the compound (D) is 0.001 to 20% by weight, preferably 0.003 to 10% by weight, and particularly preferably 0.005 to 5% by weight in the resin composition for semiconductor encapsulation of the present invention. If the amount is less than 0.001% by weight, the effect of preventing cracking in the soldering step is not sufficiently exhibited. On the other hand, when the content exceeds 20% by weight, the curing reaction of the resin composition is slowed down, the physical properties of the cured product are inferior, and the performance as a resin for semiconductor encapsulation is not preferable.

In the present invention, a curing accelerator may be used to accelerate the curing reaction between the epoxy resin and the curing agent. The curing accelerator is not particularly limited as long as it accelerates the curing reaction. For example, 2-methylimidazole, 2-methylimidazole,
Imidazoles such as phenylimidazole, amines such as benzyldimethylamine, 1,8-diazabicyclo (5,4,0) undecene-7 (abbreviated as DBU), triphenylphosphine, tetraphenylformonium, tetraphenylborate, etc. Are preferably used.

The resin composition of the present invention is optionally silicone rubber,
Rubbery polymers such as olefin rubbers and diene rubbers,
Release agents such as wax, coloring agents such as carbon black, coupling agents, brominated compounds, flame retardants such as antimony oxide, and silicone oil can be used.

The resin composition of the present invention is preferably melt-kneaded,
A known method can be used for the melt kneading. For example, melt kneading can be performed using a Banbury mixer, a kneader, a roll, a single or twin screw extruder, a co-kneader, or the like.

<Example> Hereinafter, the present invention will be specifically described with reference to examples.

In the examples, parts and% mean parts by weight and% by weight, respectively.

Examples 1 to 17, Comparative Examples 1 to 13 The raw materials shown in Table 1, the fillers shown in Table 2, and the various compounds (D) shown in Table 3 were blended in the composition ratios shown in Table 3 And dry blended with a mixer. This is mixed with a mixing roll having a roll surface temperature of 90 ° C. for 5 minutes.
After heating and kneading for minutes, the mixture was cooled and pulverized to produce a resin composition.

A 44-pin flat package was molded by a low-pressure transfer molding machine under the conditions of 180 ° C. × 2 minutes using a lead frame made of 42 alloy on which the resin composition and the simulated element were mounted, and then cured at 180 ° C. for 5 hours.

Obtain the cured flat package at 85 ° C and 85% RH
After humidification treatment for 72 hours, it was immersed in a solder bath at 260 ° C. for 10 seconds, and the state of crack generation after immersion was examined.

 Table 3 shows the results.

In Table 3, the solder heat resistance is indicated by the number of packages in which no crack occurred in 20 packages.

The following is clear from the results in Table 3.

As seen in Examples 1 to 17, the compound (D) was contained, and the powdery filler was fine powder having a particle diameter of 14 μ or less.
The package sealed with the resin composition of the present invention containing 50% by weight or more hardly cracks even when immersed in a 260 ° C solder bath after humidification at 85 ° C / 85% RH and has solder heat resistance. Are better.

On the other hand, as seen in Comparative Examples 1 to 5, even if the fine powder filler contains fine powder particles of 14 μ or less in an amount of 50% by weight or more, the resin composition containing no compound (D) can be used in almost all packages. Cracks occur.

As shown in Comparative Examples 6 to 11, even when the compound (D) was contained, the powdery filler reduced fine powder particles having a particle diameter of 14 μ
Cracks occur in most packages when the resin composition contains less than about 10% by weight.

As can be seen in Comparative Examples 12 and 13, the powdery filler containing no compound (D) contained 50 μm
Cracks occur in all the packages in the resin composition containing less than the weight percentage.

<Effects of the Invention> The resin composition of the present invention has extremely excellent solder heat resistance. By sealing with the resin composition of the present invention, the occurrence of resin cracks in the soldering step when mounting a semiconductor device is prevented. can do. Utilizing this feature, application to various uses such as sealing of semiconductor devices for surface mounting is expected.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-297313 (JP, A) JP-A-62-149743 (JP, A) JP-A-61-283615 (JP, A) JP-A-61-283615 143466 (JP, A) JP-A-63-225616 (JP, A)

Claims (3)

(57) [Claims] 1. A resin composition for semiconductor encapsulation comprising an epoxy resin, a curing agent (B) and a powdery filler (C) as main components, wherein the resin composition for semiconductor encapsulation has three aromatic rings. The compound (D) having at least two adjacent hydroxyl groups and having or not having a substituent other than the hydroxyl group is 0.001 to 2
0% by weight, and the powdery filler (C) has a particle size of 1
A resin composition for encapsulating a semiconductor, comprising 50% by weight or more of fine powder particles of 4 μ or less. 2. A semiconductor device in which a semiconductor element is sealed with the resin composition for semiconductor sealing according to claim 1. 3. An epoxy resin, a curing agent (B), and a particle diameter of 14 μm.
A powder filler (C) containing 50% by weight or more of the following fine powder particles, and a compound having three or more adjacent hydroxyl groups on an aromatic ring and having or not having a substituent other than the hydroxyl group (D) in a resin composition for encapsulating a semiconductor in an amount of 0.001 to 2
A method for producing a resin composition for encapsulating a semiconductor, which comprises melting and kneading at a ratio of 0% by weight.