JPS6181426A - Epoxy resin composition for encapsulatingj semiconductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an epoxy resin composition for semiconductor encapsulation that has excellent moisture resistance and thermal shock resistance.

[Technical background of the invention and its problems]

Conventionally, hermetic sealing using metals, ceramics, etc. was used as a sealing technology for semiconductor devices.
Recently, resin encapsulation has become mainstream because it is economically advantageous.

Epoxy resin compositions for low-pressure molding, which can be used in low-pressure transfer molding methods suitable for mass production, are generally widely used as such resins for semiconductor encapsulation. However, for example, an epoxy resin composition comprising an epoxy resin novolac type phenolic resin curing agent, an imidazole curing accelerator, etc.

Conventional resin-sealed semiconductor devices obtained by transfer molding have the following drawbacks. In other words, (1) poor moisture resistance leads to corrosion and deterioration of aluminum electrodes, (2) poor electrical properties at high temperatures, especially when the shear current increases, and the functionality of semiconductor elements deteriorates. to decline.

(3) Since the thermal expansion coefficients of the semiconductor element and the sealing resin are different, the reliability against thermal changes is low, resulting in cracks in the semiconductor element, open defects in bonding wires, etc. Of these, (1) will be explained. Since resin-sealed semiconductor devices are sometimes used or stored in a high-temperature, high-humidity atmosphere, quality must be guaranteed even under such conditions. As a reliability evaluation test for quality assurance of moisture resistance, saturation temperature test at 85℃ or 120℃
An accelerated evaluation method involving exposure to FO water vapor has been conducted.

Recently, bias application type evaluation tests have also been conducted in which a voltage is applied to further improve acceleration performance.

However, in a resin-sealed semiconductor device using an epoxy resin composition, the encapsulation resin has hygroscopic properties, and moisture can be absorbed from the external atmosphere through the encapsulation resin layer or from the encapsulation (j). It penetrates into the interior through the interface of the lead frame and reaches the surface of the semiconductor element. As a result of the action of this moisture and impurities present in the sealing resin, the resin-sealed semiconductor device f
It causes defects due to corrosion of aluminum electrodes, wiring, etc.0 Also, when a bias voltage is applied, failures due to corrosion of aluminum electrodes and wiring occur particularly frequently due to its electrochemical action.Next (2) ) is a resin-encapsulated semiconductor! i
f: Since f is sometimes used under high temperature conditions, quality must be guaranteed even under such conditions. A typical evaluation test for this purpose is an accelerated test in which reliability is evaluated by applying a bias voltage at 80° C. to 150° C.

In such tests, for example, a phenomenon in which leakage current increases due to channeling occurs as a defect that occurs particularly frequently in devices with an M08 structure whose semiconductor surface is sensitive to external charges, or devices with a PN junction to which a reverse bias is applied. There is. This phenomenon is thought to be caused by an electric field acting on the sealing resin layer that is in contact with the surface of the element to which voltage is applied.

Next, regarding (3), since resin-sealed semiconductor devices may be used under various temperature conditions, quality must be guaranteed even under sudden temperature changes.

As an evaluation test for this purpose, for example, -60°C and +
Accelerated tests are conducted in which resin-sealed semiconductor devices are alternately exposed to an atmosphere of 200°C. In such tests, conventional resin-sealed semiconductor devices are subjected to repeated tests about 100 times.

The disadvantages were that bonding wire oven defects and chip cracks occurred.

Since Takumi's resin-sealed semiconductor device fIt has the above-mentioned drawbacks, improvements have been sought. The object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation that has excellent moisture resistance and thermal shock resistance.

[41 inventions! ! C, Essential] As a result of extensive research by the present inventors to achieve the above object, it was discovered that the epoxy resin composition shown below exhibits excellent properties.C, ie, the present invention.

(1) a) Epoxy resin b) Novolac type phenolic resin C) A curing accelerator consisting of 90 to 10% by weight of organic phosphine and 10 to 90% by weight of diazabicycloalkenes or derivatives thereof, as described in (31) + An epoxy resin composition for semiconductor encapsulation, which is blended with (b) at a ratio of 0.001 to 20 mcm%.

(2) a) Epoxy resin b) Novolac type phenolic resin C) 90-10'iii% of organic phosphine and 10-90% by weight of diazabicycloalkenes or derivatives thereof
(a) +
This is an epoxy resin composition for semiconductor encapsulation, characterized in that it is blended in a ratio of 0.001 to 20 parts by weight with respect to (b).

The epoxy resin used in the present invention is commonly known and is not particularly limited. For example, glycidyl ether type epoxy resins, glycidyl ester type epoxy resins such as bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin.

Glysodylamine type epoxy 1v fat, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic type Evo#'#4
Examples include epoxy resins having two or more tau epoxy groups in one molecule, such as k and halokenated epoxy resins. However, these epoxy resins are either 1 or 2. It may be used in a mixed system on the camp.

More preferred epoxy resin f used in the present invention
'i, Epoxy M A novolak type epoxy resin having a leaf size of 170 to 300, such as a phenol novolak type epoxy resin, a cresol novolac type epoxy resin, a halogenated phenol novolac type epoxy resin, and the like. These epoxy resins have a chlorine ion content of 10p.
pm or less and the content of hydrolyzable chlorine is preferably 0.1 or less. The reason for this is that if chlorine ions exceeding i op pm or hydrolyzable chlorine exceeding 0.1% by weight are contained, the aluminum electrodes of the sealed semiconductor element are likely to be corroded.

The curing agents for epoxy resins having two or more phenolic hydroxyl groups in one molecule used in the present invention include phenol resins, polyoxystyrene, and polyhydric phenol compounds. novolac resin, cresol novolac resin, tc
Novolac-type phenolic resins such as rt-butylphenol novolac resin and nonylphenol novolac resin, resol deaf phenolic resins, polyoxystyrenes such as polyparaoxystyrene, bisphenols, and halides of these compounds. Among these, novolac type phenolic resin and polyoxystyrene are most preferred. Further, these curing agents can be used alone or in a mixed system of two or more.

Regarding the compounding ratio of the epoxy resin and the above curing agent, the ratio of the number of phenolic hydroxyl groups in the curing agent to the number of epoxy groups in the epoxy resin (number of phenolic hydroxyl groups/number of epoxy groups) is O45.
It is desirable to mix it so that it is within the range of ~1.5. The reason for this is that outside the above range, the C2 reaction is difficult to occur sufficiently and the properties of the cured product tend to deteriorate.

The me(&-phosphine compounds used in the present invention include a tertiary phosphine compound in which R1-R8 are all organic groups in the formula (IICRt R2-P (I); a secondary phosphine compound in which only R8 is hydrogen) , R2 and R8 are both hydrogen.Specifically, triphenylphosphine, tributylphosphine, tricyclohexylphosphine, methyldiphenylphosphine, butylphenylphosphine,
Diphenylphosphine, phenylphosphine, octylphosphine, etc. Further, R1 may be an organic group containing an organic phosphine. Examples include 1,2-bis(diphenylphosphino)ethane and bis(diphenylphosphino)methane.

Among these, arylphosphines are preferred, and triarylphosphines such as triphenylphosphine are particularly preferred. Further, these organic phosphine compounds may be used alone or in a mixed system of 2 m or more. Examples of the diazabicycloalkea used in the present invention include 1,8-diazabicyclo (5°4.0)
Undecene-7,1,8-diazabicyclo (7゜2.0
) Undecene-8,1,8-diazabicyclo (7°3.
0) Dodecene-8,1,8-diazabicyclo (7°4.
0)) Lysocene-8,1,8-diazabicyclo (5゜3
．． 0) Decene-7,1,8-diazabicyclo(7,5゜0)Tetradecene-8,1,10-diazabicyclo(7
゜3.0) Dodecene-9,1,10-diazabicyclo(
7,'4,0)) Lysocene-9,1,5-diazabicyclo(4゜3.0) Nonene-5,1,5-diazabicyclo(4,2゜0) Octene-5,1,5-diazabicyclo( 4,4゜0)decene-5,1,4-diazabicyclo(3,3,0)octene-4,1,6-diazabicyclo(5,5,0)dodecene-6,1,7-diazabicyclo(4, 3,0) nonene-6,1,7-diazabicyclo(
6,5,O)) lysocene-7 and the like. The next example of a manen derivative is phenol salt, 2-ethylhexanoate.

Formate, tnl! I! Examples include various salts such as salt, carbonate, and phosphite. Among these, 1,8-diazabicyclo(5,4,0)undecene-7 is particularly preferred.

Further, these diazabicycloalkenes or derivatives thereof may be used alone or in a mixed system of two or more.

The amount of the organic phosphine and diazabicycloalcarea or its derivatives may generally be within the range of 0.001 to 20 times the resin component (total amount of epoxy resin and curing agent), but a particularly preferable property is 0. 0.01 to 5% by weight. If the blending amount is less than 0.01 wtfjk%,
There is a disadvantage that the effect of addition is not measurable and that it takes a long time to harden the epoxy resin composition, but if it exceeds 20 ffi-chi, it does not adversely affect the quality.

The epoxy resin composition of the present invention can be blended with an inorganic photonic agent if necessary, but especially in the case of transfer molding of semiconductor elements such as integrated circuits and transistors, an inorganic photonic agent is blended into the epoxy resin composition of the present invention. It is preferable.

One reason for this is to improve the characteristics, but another reason is to reduce the difference in thermal expansion coefficient between the parts to be encapsulated, such as elements, bonding wires, and lead frames, and the encapsulating resin. This is to reduce defects such as wire breakage that occur due to a large difference in thermal expansion coefficients.

Inorganic photonic agents used in the present invention include quartz glass powder, crystalline silica powder, glass fiber, Merck, alumina powder, calcium silicate powder, calcium carbonate powder, barium sulfate powder, magnesia powder, etc. Among these, quartz glass powder and crystalline silica powder are most preferred in terms of high purity and low coefficient of thermal expansion. However, the blending amount of these inorganic photonic agents varies depending on the type of epoxy resin, curing agent, and inorganic photonic agent, but for example, when used in transfer molding, the TjLjd ratio is 1 with respect to the total amount of epoxy resin and curing agent. It may be .5 times to 4 times as large. Regarding the particle size distribution of the inorganic photonic agent, moldability can be improved by making the distribution uniform by combining coarse particles and fine particles.

The epoxy resin composition according to the present invention may contain, if necessary, a mold release agent such as natural waxes, synthetic waxes, metal salts of direct fatty acids, acid amides, esters or fl halaffins, chlorinated paraffin, Flame retardants such as bromotoluene, hexabromobenzene, and antimony trioxide, colorants such as carbon black, silane coupling agents, and the like may be appropriately added and blended.

A general method for preparing the epoxy resin composition of the present invention as a molding material is to thoroughly mix the raw material components selected at a predetermined composition ratio, for example, with a mixer, and then melt-mix them with heated rolls, or An epoxy resin molding material can be easily obtained by adding a mixing treatment using a kneader or the like.

A resin-encapsulated semiconductor device using the epoxy resin composition of the present invention can be easily manufactured by encapsulating the semiconductor device using the epoxy resin composition or molding material described above. The most common method of sealing is low-pressure transfer molding, but injection molding, compression molding,
Sealing by casting or the like is also possible.

The epoxy resin composition or molding material is heated and cured during sealing, and finally a resin-sealed semiconductor device can be obtained which is sealed with the cured product of this composition or molding material. It is particularly desirable to heat to 150° C. or higher during curing.

The semiconductor device mentioned above is an integrated circuit, a large-scale integrated circuit transistor, a thyristor, a diode, etc., and is not particularly limited.

[Effects of the Invention] The epoxy resin composition of the present invention has excellent moisture resistance and thermal shock resistance, and when applied to semiconductor encapsulation, can significantly improve disconnection defects in semiconductor device wiring. It is.

[Examples of the Invention] Examples 1 to 6 and Comparative Examples 1 to 3 Cresol novolak type epoxy resin with epoxy equivalent weight of J1220 (epoxy resin A), brominated epoxy novolak resin with epoxy equivalent weight of 290 (epoxy resin B),
Phenolic novolac resin curing agent with molecule 1L8oo,
) Riphenylphosphine, 1,8-diazabicyclo(5
,4,0) undecene-7 (DBU), phenol salt of DBU, fused silica powder, antimony trioxide, carnauba wax, carbon black, silane coupling agent (r
-glycidoxypropyltrimethoxysilane) in the composition shown in Table 1 (N position), and each composition! Mixing with a mixer and mixing with heated rolls (2)
Nine transfer molding materials were prepared including a comparative example.

Using the molding material thus obtained, an MO8 type integrated circuit was resin-sealed by transfer molding. Sealing was performed by heating to 90°C with a high frequency preheater, molding the molding material at 170°C for 2 minutes, and then after-curing at 180°C for 4 hours. Therefore, two thermostats at +200°C and -65°C were prepared, and Examples 1 to 6 and Comparative Examples 1 to 6 were prepared.
1,001 pieces of each of the resin-sealed semiconductor devices of No. 3 were placed in a constant temperature bath at +200° C. and left for 30 minutes. Thereafter, it was taken out and left at room temperature for 5 minutes, and then placed in a constant temperature bath at -65°C for 30 minutes. Thereafter, it was taken out and left at room temperature again for 5 minutes.

The above operations are regarded as one cycle, and a thermal cycle test is carried out continuously, the cycle is interrupted at any time according to the progress of the FCO thermal cycle test, the characteristics of the resin-sealed semiconductor device are measured using a tester, and defects are detected. Examined. The result is the second
Shown in the table. In addition, each resin-sealed semiconductor device was heated to 120°C.
, Humidity test (bias
PCT) was conducted and the results are shown in Table 3.

Margin below

Claims (2)

[Claims] (1) a) Epoxy resin b) Novolac type phenolic resin c) A curing accelerator consisting of 90 to 10% by weight of organic phosphine and 10 to 90% by weight of diazabicycloalkenes or derivatives thereof is added to the above (a)
1. An epoxy resin composition for semiconductor encapsulation, characterized in that it is blended in a proportion of 0.001 to 20% by weight based on (b). (2) a) Epoxy resin b) Novolac type phenolic resin c) A curing accelerator consisting of a molten mixture of 90 to 10% by weight of organic phosphine and 10 to 90% by weight of diazabicycloalkenes or derivatives thereof. ) + 0.001 for (b)
An epoxy resin composition for semiconductor encapsulation, characterized in that it is blended in a proportion of ~20% by weight.