JPH11279379A - Epoxy resin composition for sealing of semiconductor, and semiconductor apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for sealing of a semiconductor which can be fire-retardant by use of a red phosphorus without decrease of reliability of moisture resistance of the semiconductor and does not necessitate mixing of an ion scavenger. SOLUTION: The epoxy resin composition for sealing of a semiconductor mainly comprises an epoxy resin, a hardening agent, an hardening accelerator and an inorganic filler. A fire retardant comprising a fine particle of a red phosphorus having a average diameter of 1-6 μm and a thermosetting resin layer and an inorganic layer covering the surface thereof is mixed in the composition. It is possible to make the composition to be fire-retardant by use of the red phosphorus without use of a halogen-based fire retardant or an antimony trioxide and to maintain stability of the red phosphorus by the thermosetting resin layer or the inorganic layer which prevents the red phosphorus from absorbing moisture. It is further possible, by use of the fine particle of the red phosphorus having an average diameter of 1-6 μm, to obtain a red phosphorus-based fire retardant having a small diameter with keeping thickness of thermosetting resin layer or the inorganic layer which can be easily dispersed in the epoxy resin composition for sealing semiconductor and to maintain reliability of moisture resistance without use of an ion scavenger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for encapsulating a semiconductor used for encapsulating a semiconductor and a semiconductor device using the epoxy resin composition for encapsulating a semiconductor.

[0002]

2. Description of the Related Art An epoxy resin composition for semiconductor encapsulation is mainly composed of an epoxy resin, a curing agent, a curing accelerator, an inorganic filler such as fused silica or crystalline silica, and a flame retardant. Has been prepared. Conventionally, halogen-based flame retardants such as brominated epoxy resins and antimony compounds such as antimony trioxide have been mainly used as flame retardants, but these halogen-based flame retardants and antimony compounds have been used in view of environmental health and the like. There's a problem.

For this reason, the use of red phosphorus as a flame retardant instead of halogen-based flame retardants and antimony compounds has been studied. For example, Japanese Patent Application Laid-Open No. 8-151427 discloses a technique using a red phosphorus-based flame retardant in the presence of an ion scavenger. And this Japanese Patent Laid-Open No. 8-15
In Japanese Patent No. 1427, the red phosphorus-based flame retardant is prepared by coating red phosphorus with a phenol resin or a mixture of aluminum hydroxide and a phenol resin.

[0004]

However, red phosphorus can provide a high flame-retardant effect with a small amount of addition, but is easily absorbed by moisture and reacts with a small amount of absorbed moisture to form phosphine gas or corrosive phosphorus. Since the acid is generated, there is a possibility that the characteristics of the semiconductor are deteriorated and the humidity resistance reliability is significantly reduced. Therefore, it is conceivable to use red phosphorus as a red phosphorus-based flame retardant coated with a phenolic resin or a mixture of aluminum hydroxide and a phenolic resin as disclosed in Japanese Patent Application Laid-Open No. 8-151427. In the case of JP-A-151427, it is necessary to use an ion scavenger in combination in order to enhance the reliability, and this is not practical in terms of cost and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in view of a semiconductor which can be made flame-retardant with red phosphorus without deteriorating the humidity resistance of the semiconductor and which does not need to contain an ion scavenger. An object is to provide an epoxy resin composition for sealing and a semiconductor device.

[0006]

The epoxy resin composition for semiconductor encapsulation according to the present invention comprises an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler as main components, and has an average particle size of 1 to 6 μm.
Characterized in that a flame retardant comprising a thermosetting resin layer and an inorganic layer coated on the surface of the finely powdered red phosphorus is blended.

[0007] The invention of claim 2 is characterized in that the flame retardant has an average particle size of 15 µm or less.

The invention according to claim 3 is characterized in that the thermosetting resin is a phenol resin or an epoxy resin.

According to a fourth aspect of the present invention, the inorganic layer is made of aluminum hydroxide or titanium hydroxide.

[0010] A semiconductor device according to the present invention is characterized in that a semiconductor is sealed with the epoxy resin composition for semiconductor sealing described above.

[0011]

Embodiments of the present invention will be described below.

In the present invention, any epoxy resin may be used without limitation as long as it is used for semiconductor encapsulation. For example, o-cresol novolak epoxy resin, biphenyl epoxy resin, dicycloepoxy resin Examples thereof include a pentadiene type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bromo-containing epoxy resin.

The curing agent is not particularly limited as long as it is used for curing an epoxy resin. Examples of the curing agent include phenol novolak resins, cresol novolak resins, phenol aralkyl resins, naphthol aralkyl resins, and various polyphenol resins such as polyphenol resins. Resins can be mentioned.

The curing accelerator is not particularly limited, but includes organic phosphines such as triphenylphosphine; tertiary amines such as diazabicycloundecene;
Imidazoles such as 2-methylimidazole and 2-phenylimidazole can be used.

As the inorganic filler, any one used for semiconductor encapsulation, such as fused silica, crystalline silica, alumina and silicon nitride, can be used.

In the present invention, red phosphorus is blended as a flame retardant. The surface of red phosphorus particles is coated with a thermosetting resin layer and an inorganic layer to be used as a flame retardant. As this red phosphorus, fine red phosphorus having an average particle diameter of 1 to 6 μm is used. By coating the surface of the fine red phosphorus with a thermosetting resin layer and an inorganic layer, moisture absorption of the fine red phosphorus is reduced. Thus, the stability of the fine red phosphorus can be maintained, and the humidity resistance of the semiconductor device can be maintained. Either the thermosetting resin layer or the inorganic layer coated on the fine red phosphorus may be inside or outside.

In the present invention, the thickness of the coating layer of the thermosetting resin layer and the inorganic layer is ensured by using fine powdered red phosphorus having an average particle diameter of 1 to 6 μm as the raw material red phosphorus as described above. It is possible to obtain a red phosphorus-based flame retardant having a small particle size while performing the method. By using such a small particle of the red phosphorus-based flame retardant, the flame retardant can be uniformly dispersed in the epoxy resin composition for semiconductor encapsulation. It becomes easy to disperse, a high flame retardant effect can be obtained, and the amount of phosphine gas generated at the time of moisture absorption heating is reduced, the reliability of the semiconductor device against moisture is improved, and an ion scavenger is added. It is unnecessary. Therefore, if the average particle size of the starting red phosphorus exceeds 6 μm, such effects cannot be sufficiently expected. Although the average particle size is preferably as small as possible, it is practically difficult to obtain red phosphorus having an average particle size of 1 μm, so that the average particle size of 1 μm is the practical lower limit.

The average particle size of the red phosphorus-based flame retardant prepared by coating the surface of the finely powdered red phosphorus with a thermosetting resin layer and an inorganic layer is 15 μm or less in order to sufficiently obtain the above effect. Preferably, there is. When the average particle size of the red phosphorus-based flame retardant is 15 μm or less, in addition to the above-described effects, an effect of improving the moldability in the encapsulation molding of the epoxy resin composition for semiconductor encapsulation can be obtained. Although the lower limit of the average particle diameter of the red phosphorus-based flame retardant is not particularly set, it is practically preferable to set the lower limit to about 2 μm in order to secure the thickness of the coating layer of the thermosetting resin and the inorganic material.

In the above-mentioned red phosphorus-based flame retardant prepared by coating the surface of red phosphorus with a thermosetting resin layer and an inorganic layer, the content of red phosphorus is 50 to 95% by weight, It is preferable that the content of the layer is 1 to 29% by weight and the content of the inorganic layer is 1 to 29% by weight. If the content of red phosphorus is less than 50% by weight, it is necessary to incorporate a large amount of a red phosphorus-based flame retardant in order to obtain flame retardancy. The amount of the coating with the curable resin layer and the inorganic layer is reduced, so that it becomes difficult to prevent the absorption of red phosphorus and to maintain the stability of red phosphorus, and it is also difficult to maintain the moisture resistance reliability of the semiconductor device.

Here, the thermosetting resin forming the thermosetting resin layer is not particularly limited. For example, a phenol resin, an epoxy resin, a xylene
Formaldehyde resin, ketone / formaldehyde resin, urea resin, melamine resin, aniline resin, alkyd resin, unsaturated polyester resin and the like can be used. Among these thermosetting resins, especially phenolic resins,
Epoxy resins are preferred.

The inorganic material forming the above-mentioned inorganic layer is not particularly limited. For example, aluminum hydroxide, titanium hydroxide, titanium dioxide, aluminum oxide, zinc oxide, magnesium oxide, magnesium carbonate, silicate Aluminum, barium sulfate, calcium sulfate, calcium phosphate, apatite, talc, bentonite, kaolin, diatomaceous earth and the like can be used.

The epoxy resin composition for encapsulation according to the present invention comprises an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler as main components, to which the above-mentioned red phosphorus-based flame retardant is blended. Accordingly, a mold release agent such as carnauba wax, stearic acid, montanic acid, and a carboxyl group-containing polyolefin, a colorant such as carbon black, a silane coupling agent, and a silicone flexible agent are blended, and the resulting mixture is uniformly mixed with a mixer or blender. And then kneading by heating and kneading with a kneader or a roll. The kneaded material may be cooled and solidified as required, and may be pulverized and used in the form of powder.

Here, the compounding amount of each of the above components is appropriately set according to the type of each component, the required performance, and the like. The compounding amount of the red phosphorus-based flame retardant is It is preferable to set the amount in the range of 1 to 4 parts by weight based on 100 parts by weight of the organic component of the epoxy resin composition.

The semiconductor device can be manufactured by encapsulation using the epoxy resin composition for semiconductor encapsulation prepared as described above. For example, I
By setting a lead frame on which a semiconductor such as C is mounted in a transfer molding die and performing transfer molding, a semiconductor device in which the semiconductor is encapsulated in a molded product of an epoxy resin composition for semiconductor encapsulation can be manufactured. Things.

[0025]

Next, the present invention will be described specifically with reference to examples.

Example 1 The components shown in Table 1 were blended. Here, as a red phosphorus-based flame retardant, an average particle size of 2.5 μm
100 parts by weight of finely divided red phosphorus having a mean particle size of 6 μm and an inorganic layer of aluminum hydroxide coated at about 2 parts by weight and a thermosetting resin layer of phenol resin at a coating amount of about 5 parts by weight. "NOVA Excel F5"
(Shown as red phosphorus-based flame retardant (1) in Table 1).

These components were mixed in a blender, kneaded with a biaxial hot roll at 85 ° C. for 5 minutes, and then pulverized to prepare an epoxy resin composition for semiconductor encapsulation.

(Example 2) Each component shown in Table 1 was blended. Here, as the red phosphorus-based flame retardant, 17 parts by weight of an inorganic layer of titanium hydroxide in terms of titanium and a thermosetting resin layer of a phenol resin in place of the surface coating of the red phosphorus flame retardant shown in Example 1 were used. A coating having an average particle size of 8 μm coated at a coating amount of 5 parts by weight (shown as red phosphorus-based flame retardant (2) in Table 1) was used. Then, an epoxy resin composition for semiconductor encapsulation was prepared in the same manner as in Example 1.

Example 3 The components shown in Table 1 were blended. Here, as the red phosphorus-based flame retardant, instead of the surface coating of the red phosphorus-based flame retardant shown in Example 1, 35 parts by weight of an inorganic layer of titanium hydroxide in terms of titanium and a thermosetting resin layer of phenol resin were used. A coating having an average particle diameter of 10 μm coated with a coating amount of 5 parts by weight (indicated in Table 1 as a red phosphorus-based flame retardant (3)) was used. Then, an epoxy resin composition for semiconductor encapsulation was prepared in the same manner as in Example 1.

Example 4 The components shown in Table 1 were blended. Here, as the red phosphorus-based flame retardant, instead of the surface coating of the red phosphorus-based flame retardant shown in Example 1, 20 parts by weight of a thermosetting resin layer made of an epoxy resin and an inorganic layer made of titanium hydroxide were converted to titanium. A coating having an average particle size of 15 μm coated at a coating amount of 34 parts by weight (shown as red phosphorus-based flame retardant (4) in Table 1) was used. Then, an epoxy resin composition for encapsulating a semiconductor was obtained in the same manner as in Example 1.

Example 5 The components shown in Table 1 were blended. As the red phosphorus-based flame retardant, instead of the surface coating of the red phosphorus-based flame retardant shown in Example 1, 10 parts by weight of a thermosetting resin layer made of epoxy resin and 17 parts by weight of an inorganic layer made of titanium hydroxide in terms of titanium were used. The particles having an average particle size of 9 μm (shown in Table 1 as red phosphorus-based flame retardant (5)) were used. Then, an epoxy resin composition for encapsulating a semiconductor was obtained in the same manner as in Example 1.

Comparative Example 1 The components shown in Table 2 were blended. Here, a brominated epoxy resin and antimony trioxide were blended as a flame retardant. Then, an epoxy resin composition for encapsulating a semiconductor was obtained in the same manner as in Example 1.

Comparative Example 2 Each component shown in Table 2 was blended. Here, as a red phosphorus-based flame retardant, an average particle diameter of 28 μm
100 parts by weight of granular red phosphorus was coated with about 2 parts by weight of an inorganic layer made of aluminum hydroxide and about 5 parts by weight of a thermosetting resin layer made of a phenol resin. "NOVA Excel 140"
(Shown as red phosphorus-based flame retardant (6) in Table 2).
Then, an epoxy resin composition for encapsulating a semiconductor was obtained in the same manner as in Example 1.

Comparative Example 3 Each component shown in Table 2 was blended. Here, as the red phosphorus-based flame retardant, 17 parts by weight of an inorganic layer of titanium hydroxide in terms of titanium in place of the surface coating of the red phosphorus-based flame retardant shown in Comparative Example 2, and 5 parts of a thermosetting resin layer of phenol resin were used. The particles having an average particle size of 38 μm coated in parts by weight (shown as red phosphorus-based flame retardant (7) in Table 2) were used. Then, an epoxy resin composition for semiconductor encapsulation was prepared in the same manner as in Example 1.

[0035]

[Table 1]

[0036]

[Table 2] A moisture resistance reliability test was performed as follows.

A 16-pin DIP mounted with a semiconductor chip having a comb-shaped circuit having a circuit width and a space between circuits of 3 μm each.
Using a sealing epoxy resin prepared in Examples 1 to 5 and Comparative Examples 1 to 3 as described above, a frame is sealed and molded at 175 ° C. for 90 seconds by a low-pressure tonlas fur molding machine. And a 16-pin DIP.

Using this 16-pin DIP as a sample,
SPCBT (Un Saturated Pressure Cooker Baias Tes
t: Unsaturated high-temperature high-pressure high-humidity bias test) and PCT (pressure cooker test) tests were performed to evaluate the humidity resistance reliability.

The USPCBT test was conducted at 85 ° C. and 85% RH.
Under the conditions described above, a voltage of 25 V was applied between two parallel circuits of the sample, and the treatment was performed for 200 hours and 500 hours.
The number of samples out of which the circuit failure occurred was counted and performed. The results are shown in Table 3 by displaying the number of samples in the denominator and the number of defective circuits in the numerator.

In the PCT test, a sample was subjected to 2 atm, 121 ° C.
Under conditions of 100% RH, 200 hours, 300 hours, 50 hours
After the treatment for 0 hour, the number of circuit failures out of the ten samples was counted. Table 3 shows the results.
The number of samples is shown in the denominator, and the number of circuit failures is shown in the numerator.

Using the sealing epoxy resins prepared in Examples 1 to 5 and Comparative Examples 1 to 3, test pieces were prepared in accordance with UL94, and a flame test was conducted to measure the flame retardancy. Table 3 shows the results.

[0042]

[Table 3] As can be seen from Table 3, each of the examples using a red phosphorus-based flame retardant in which the surface of fine powdered red phosphorus having an average particle diameter of 1 to 6 μm was coated with a thermosetting resin layer and an inorganic layer was a flame retardant. As in Comparative Example 1 using a brominated epoxy resin and antimony trioxide. In Comparative Examples 2 and 3 using a red phosphorus-based flame retardant obtained by coating the surface of granular red phosphorus having an average particle diameter of 28 μm with a thermosetting resin layer and an inorganic layer, the moisture resistance reliability was significantly low. Yes,
In Comparative Example 3, the moisture resistance reliability was not significantly improved even when the coating amount of the coating was increased.

[0043]

As described above, the present invention provides an epoxy resin,
A flame retardant comprising a curing agent, a curing accelerator, and an inorganic filler as main components, and a thermosetting resin layer and an inorganic layer coated on the surface of finely powdered red phosphorus having an average particle diameter of 1 to 6 μm. Therefore, it is not necessary to use halogen-based flame retardants or antimony trioxide, which are problematic in terms of environmental hygiene, and can be made flame-retardant with red phosphorus. In addition, a thermosetting resin layer coated on the surface of red phosphorus In addition to preventing red phosphorus from absorbing moisture in the inorganic layer, the stability of red phosphorus can be maintained, and the use of finely powdered red phosphorus having an average particle size of 1 to 6 μm allows the thermosetting resin layer and the inorganic layer to have a fine particle size. A red phosphorus flame retardant with a small particle size can be obtained while securing the coating thickness,
It becomes easy to uniformly disperse the red phosphorus-based flame retardant in the epoxy resin composition for semiconductor encapsulation, and it is possible to maintain the moisture resistance reliability of the encapsulated semiconductor device without using an ion scavenger. Things.

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Claims (5)

[Claims] 1. A thermosetting resin layer and an inorganic layer coated on the surface of finely powdered red phosphorus having an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler as main components and having an average particle size of 1 to 6 μm. An epoxy resin composition for semiconductor encapsulation, comprising a flame retardant. 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the flame retardant has an average particle size of 15 μm or less. 3. The thermosetting resin according to claim 1, wherein the thermosetting resin is a phenol resin or an epoxy resin.
The epoxy resin composition for semiconductor encapsulation according to the above. 4. The method according to claim 1, wherein the inorganic layer is made of aluminum hydroxide or titanium hydroxide.
The epoxy resin composition for semiconductor encapsulation according to any one of the above. 5. A semiconductor device comprising a semiconductor encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.