JPH0597969A - Thermosetting resin composition and semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a thermosetting resin composition, excellent in fluidity, having a low expansion coefficient and high glass transition temperature, improved in heat resistance, capable of providing cured products having low hygroscopicity and suitable for sealing semiconductor devices. CONSTITUTION:A thermosetting resin composition is obtained by blending (A) 100 pts.wt. naphthalene ring-containing epoxy resin with <=10wt.% content of a compound expressed by formula I [R<1> is H or 1-6C alkyl; OG is glycidyl; (n)is 1 or 2] with (B) 30-100 pts.wt. preferably 40-70 pts.wt. naphthalene ring- containing phenolic resin with <=10wt.% content of a compound expressed by formula II and (C) an inorganic filler (e.g. fused silica or crystalline silica) in an amount of 200-1000 pts.wt., preferably 250-700 pts.wt. based on 100 pts.wt. total amount of the resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermosetting resin composition having a good fluidity, a small expansion coefficient, a high glass transition temperature, a good heat resistance, and a low hygroscopic cured product. The present invention relates to a semiconductor device encapsulated with an object and a cured product thereof.

[0002]

2. Prior Art and Problems to be Solved by the Invention
In the semiconductor industry, resin-sealed diodes, transistors, ICs, LSIs, and VLSIs have become the mainstream. When encapsulating these semiconductor devices, epoxy resin is generally superior to other thermosetting resins in terms of moldability, adhesiveness, electrical characteristics, mechanical characteristics, moisture resistance, etc. BACKGROUND ART Semiconductor devices are often sealed.

On the other hand, these semiconductor devices have recently become more and more integrated, and the chip size is also correspondingly increasing. On the other hand, the outer dimensions of the package are becoming smaller and thinner in accordance with the demand for smaller and lighter electronic devices. Further, also in the method of mounting a semiconductor component on a circuit board, the surface mounting of the semiconductor component has been widely performed due to the high density of components on the substrate and the thinning of the substrate.

However, when the semiconductor device is surface-mounted, a general method is to immerse the entire semiconductor device in a solder bath or pass through a high temperature zone where the solder melts. A crack may occur in the layer, or peeling may occur at the interface between the lead frame or chip and the sealing resin. Such cracks and peeling become more noticeable if the sealing resin layer of the semiconductor device absorbs moisture before the thermal shock during surface mounting, but in the actual working process, the moisture absorption of the sealing resin layer Inevitably, the reliability of the semiconductor device sealed with the epoxy resin after mounting may be greatly impaired.

The present invention has been made in view of the above circumstances.
A thermosetting resin composition having good flowability, a low expansion coefficient, a low stress, a high glass transition temperature, good heat resistance, and a low hygroscopicity, and a composition sealed with this composition. It is an object of the present invention to provide a semiconductor device having high reliability in thermal shock and moisture resistance during stopped surface mounting.

[0006]

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a naphthalene ring-containing epoxy resin and a naphthalene ring-containing phenol resin are further mixed with an inorganic filler. In the epoxy resin composition, the naphthalene ring-containing epoxy resin and the naphthalene ring-containing epoxy resin in which the content of the compound (naphthol derivative) represented by the following formula (1) is 10% by weight or less is used as the naphthalene ring-containing epoxy resin and the naphthalene ring-containing phenol resin, respectively. Compound represented by formula (2) (naphthol derivative)
By using a naphthalene ring-containing phenol resin having a content of 10% by weight or less and a content of the compounds of the formulas (1) and (2) of 10% by weight or less based on the total amount of the resin. Of high heat resistance and low hygroscopicity while having a high expansion coefficient, a low expansion coefficient and a high glass transition temperature, and further sealed with this cured product. It has been found that the semiconductor device has excellent reliability.

[0007]

[Chemical 3] (However, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, OG is a glycidyl group, n is 1 or 2, and may be added to any ring of the naphthalene ring, and may be added to both rings at the same time. You may.)

[0008]

[Chemical 4] (However, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, n is 1 or 2, and may be added to any ring of the naphthalene ring, or may be added to both rings at the same time. )

That is, an epoxy resin composition using a naphthalene ring-containing epoxy resin or a naphthalene ring-containing phenol resin as an epoxy resin is disclosed in JP-A-3-43412, JP-A-3-21627, JP-A-3-59020, and JP-A-3-59020.
JP-A-39323, etc., which contain an epoxy resin or a phenol resin containing a naphthalene ring as a main component, and have excellent characteristics which have never been obtained as a resin for a thin package.

However, since the present inventor uses conventional epoxy resin or phenol resin containing a naphthalene ring as α-naphthol, α, β-naphthol, β, β-naphthol derivative or the like as a raw material, the phenol resin And that there is a considerable amount of unreacted naphthol derivative remaining in the epoxy resin, and the semiconductor device is sealed with an epoxy resin composition using an epoxy resin or phenol resin that has a certain amount of such unreacted material remaining. When stopped, it was found that there is a problem that defects occur in high temperature storage and humidity resistance test, and the content of the naphthol derivative of formula (1) and formula (2) in the resin is limited as described above. It was found that the above problems hardly occur and that a high quality semiconductor device is obtained by encapsulating with a cured product of this composition. The present invention has been completed.

The present invention will be described in more detail below. The component (a) of the present invention is a naphthalene ring-containing epoxy resin, and various kinds of naphthalene ring-containing epoxy resins are selected. In particular, the following general formula (3) is used. Those represented by are preferably used.

[0012]

[Chemical 5]

The following compounds can be mentioned as specific examples of such naphthalene ring-containing epoxy resin.

[0014]

[Chemical 6]

[0015]

[Chemical 7]

Thus, in the present invention, as the above naphthalene ring-containing epoxy resin, a compound represented by the following formula (1) is used in an amount of 10% by weight or less.

[0017]

[Chemical 8]

In the formula, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group, OG is a glycidyl group, and n is 1 or 2. The R ¹ and OG groups may be added to any ring of the naphthalene ring, or may be added to both rings at the same time.

Examples of such a compound of formula (1) include the following compounds.

[0020]

[Chemical 9]

In this case, the naphthalene ring-containing epoxy resin needs to contain the compound of the above formula (1) in an amount of 10% by weight or less. In particular, the content is 7% by weight or less in heat resistance. , Desirable from the viewpoint of moisture resistance. When the content of the compound of the formula (1) exceeds 10% by weight, the glass transition temperature is lowered, and the semiconductor devices sealed with the various resin layer compositions have large fluctuations in resistance value at high temperature for a long period of time. In some cases, the initial characteristics may not be retained, or wire breakage may occur. In addition to this, it is preferable that the content of the binuclear body composed of only phenol and phenylglycidyl ether is 1% by weight or less, particularly 0.5% by weight or less.

The softening point of the epoxy resin of component (a) is affected by the content of the compound of formula (1), but the softening point is 50.
It is desirable that the resin has an epoxy equivalent of 100 to 400, especially 120 to 120 ° C, especially 70 to 110 ° C. Softening point is 50
When an epoxy resin having a temperature of less than 0 ° C. is used, not only the glass transition temperature of the cured product is lowered, but also burrs and voids are likely to occur during molding. If the softening point exceeds 120 ° C, the viscosity may be too high and molding may not be possible.

When the composition of the present invention is used for encapsulating a semiconductor, the epoxy resin as the component (a) preferably has a hydrolyzable chlorine content of 1000 ppm or less, particularly 500 ppm or less, and sodium or potassium content of 10 ppm or less. When the semiconductor device is sealed with a resin having hydrolyzable chlorine exceeding 1000 ppm and sodium and potassium exceeding 10 ppm, and the semiconductor device is left under high temperature and high humidity for a long time, moisture resistance may deteriorate. An epoxy resin composition having excellent reliability can be obtained by selecting such an epoxy resin.

In the epoxy resin composition of the present invention,
As the epoxy resin, the above-mentioned naphthalene ring-containing epoxy resin is used as an essential component, but other ordinary epoxy resins can be used together. Typical of the other epoxy resins is an epoxy resin having at least two epoxy groups in one molecule, specifically, bisphenol A type epoxy resin, phenol novolac type epoxy resin, triphenol alkane. Type epoxy resin and its polymer, dicyclopentadiene modified phenol type epoxy resin, phenol aralkyl type epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, heterocyclic type epoxy resin and brominated epoxy resin.

The content of the naphthalene ring in the epoxy resin is preferably in the range of 5 to 80% by weight, more preferably 10 to 60% by weight, and the naphthalene ring-containing epoxy resin and the other epoxy are adjusted so as to be in this range. It is preferable to adjust the blending amount with the resin.

Next, as the naphthalene ring-containing phenol resin as the component (b), those represented by the following general formula (4) are preferably used.

[0027]

[Chemical 10] (Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a butyl group, B is a hydrogen atom or —OH, k is an integer of 0 to 5, and 1 is 0. ~ 3, m is an integer of 0 to 2, n is 1 or 2.
OH may be added to any ring of the naphthalene ring, or may be added to both rings at the same time. )

Specific examples of the naphthalene ring-containing phenol resin represented by the above formula (4) include the following compounds.

[0029]

[Chemical 11] (K is the same as above)

The naphthalene ring-containing phenol resin as the component (b) acts as a curing agent for the epoxy resin as the component (a). In the present invention, the naphthalene ring-containing phenol resin is represented by the following formula (2). The compound (naphthol derivative) shown is 10% by weight or less.

[0031]

[Chemical formula 12]

Here, R ¹ in the formula is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group, and n is 1 or 2. The R ¹ and OH groups may be added to any ring of the naphthalene ring, or may be added to both rings at the same time.

Examples of such a compound of formula (2) include the following compounds.

[0034]

[Chemical 13]

In this case, the naphthalene ring-containing phenol resin must contain the compound of the formula (2) in an amount of 10% by weight or less, preferably 7% by weight or less. The thermosetting resin composition using the phenolic resin of the above formula (4) exhibits excellent resistance to cracking and low moisture absorption during solder dipping after moisture absorption. A semiconductor device sealed with a thermosetting resin composition containing a phenol resin containing a naphthol derivative in an amount of more than 10% by weight as a curing agent has a large decrease in heat resistance and humidity resistance.

In addition to this, it is preferable that the content of the binuclear phenol other than the naphthol derivative and the free phenol is 1% by weight or less, particularly 0.5% by weight or less.

Further, the softening point of the phenol resin as the component (b) is influenced by the content of the compound of the formula (2), but those having a softening point of 60 to 150 ° C., particularly 70 to 130 ° C. are preferable, The hydroxyl equivalent is preferably 90 to 250. When using this phenol resin for semiconductor encapsulation, sodium and potassium are preferably 10 ppm or less, and sodium and potassium are 10 ppm.
If the semiconductor device is sealed with a resin containing more than 100% and the semiconductor device is left under high temperature and high humidity for a long time, deterioration of moisture resistance may be accelerated.

In the epoxy resin composition of the present invention,
Although the above-mentioned naphthalene ring-containing phenol resin is used as an essential component as the phenol resin, other ordinary phenol resins can be used in combination. As the other phenolic resin, any phenolic resin having at least two phenolic hydroxyl groups in one molecule can be used, and specifically, novolac type phenolic resin, resol type phenolic resin, phenol aralkyl. Examples thereof include resins, phenol resins such as triphenolalkane type resins and polymers thereof, dicyclopentadiene-modified phenol resins, and amine-based curing agents and acid anhydride-based curing agents.

The content of naphthalene ring in the phenol resin is 5 to 80% by weight, especially 10 to 60% by weight.
Is preferable, and it is preferable to adjust the compounding amount of the naphthalene ring-containing phenol resin and the other phenol resin so as to fall within this range.

In the present invention, the content of the compounds represented by the above formulas (1) and (2) is 10% by weight or less, preferably 7% by weight of the total amount of the epoxy resin and the phenol resin in the composition. Must be:
The epoxy resin as the component (a) and the phenol resin as the component (b) are selected and blended so that the content falls within the above range. When the content of the compounds of formulas (1) and (2) is less than 10% by weight, not only the glass transition temperature is lowered but also a semiconductor device sealed with such a thermosetting resin composition is left at high temperature. In that case, a defect called purple plague is likely to occur and the moisture resistance is lowered.

Further, the mixing ratio of the epoxy resin and the phenol resin is determined by the equivalent ratio of the epoxy group and the hydroxyl group. In the present invention, epoxy group / hydroxyl group = 0.5 to
2, preferably in the range of 0.8 to 1.5,
Usually, 30 to 100 parts by weight, particularly 40 to 70 parts by weight of the phenol resin is preferably used with respect to 100 parts by weight of the epoxy resin. If it is less than 30 parts by weight, sufficient strength may not be obtained, and if it exceeds 100 parts by weight, unreacted phenol resin may remain and moisture resistance may be reduced.

In the present invention, in addition to the naphthalene ring-containing epoxy resin as the component (a) and the naphthalene ring-containing phenol resin as the component (b), a silicone-modified copolymer is further added in order to further enhance the effects of the present invention. It is preferable to use them together. The silicone-modified copolymer is obtained by an addition reaction between an alkenyl-containing epoxy resin or phenol resin, or an alkenyl-containing naphthalene ring-containing epoxy resin or naphthalene ring-containing phenol resin, and the SiH group in the organopolysiloxane. Those that can be used are preferred.

Specific examples of the alkenyl group-containing epoxy resin and phenol resin, and the alkenyl group-containing naphthalene ring-containing epoxy resin and naphthalene ring-containing phenol resin include the following.

[0044]

[Chemical 14]

The organopolysiloxane to be reacted with the resin has, for example, the following structure.

[0046]

[Chemical 15]

The amount of the above silicone-modified copolymer compounded is 0 to 50 parts by weight, particularly 1 to 30 parts by weight, based on 100 parts by weight of the total amount of the components (a) and (b). If it exceeds 50 parts by weight, sufficient improvement in adhesiveness cannot be expected and, in addition, the diffusion coefficient of water of the cured product becomes large and water may easily enter.

Next, as the inorganic filler as the component (c) used in the present invention, those which are usually blended with the epoxy resin composition can be used.

The inorganic filler is used to reduce the expansion coefficient of the sealing material and reduce the stress applied to the semiconductor element. As a specific example, crushed or spherical fused silica and crystalline silica are mainly used, and in addition to these, alumina, silicon nitride, aluminum nitride and the like can also be used.

The average particle size of the inorganic filler is 5 to 20.
The micron type is preferable. In order to achieve both low expansion and moldability of the cured product, a blend of spherical and crushed products,
Alternatively, it is better to use only spherical products.

The inorganic filler of this kind is preferably surface-treated with a silane coupling agent before use.

The filling amount of the inorganic filler is preferably 200 to 1000 parts by weight, more preferably 250 to 700 parts by weight, based on 100 parts by weight of the total resin in the composition. If the filling amount is less than 200 parts by weight, the expansion coefficient becomes large, the stress applied to the semiconductor element may increase and the element characteristics may be deteriorated. If the filling amount exceeds 1000 parts by weight, the viscosity at the time of molding becomes high and the moldability becomes poor. May be.

A curing accelerator can be added as the component (d) to the composition of the present invention, and specific examples thereof include imidazole or its derivative, phosphine derivative and cycloamidine derivative.

The amount of the curing accelerator added is preferably 0.001 to 5 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the epoxy resin as the component (a). 0.001
If it is less than 5 parts by weight, it may not be possible to cure it in a short time, and if it exceeds 5 parts by weight, the curing rate may be too fast to obtain a good molded product.

In the present invention, in order to impart flexibility and toughness to the cured product of the thermosetting resin composition, various organic synthetic rubbers,
Methyl methacrylate-styrene-butadiene copolymer,
A thermoplastic resin such as a styrene-ethylene-butene-styrene copolymer, or a fine powder such as a silicone gel or a silicone rubber can be added. The surface of the inorganic filler may be treated with a two-component type silicone rubber or silicone gel. The silicone-modified copolymer and styrene-butadiene-methyl methacrylate copolymer described above are effective in reducing the stress of the epoxy resin.

The amount of the thermoplastic resin used as the stress reducing agent is usually 0.5 to 10% by weight based on the whole thermosetting resin composition,
Particularly, 1 to 5% by weight is preferable. A blending amount of less than 0.5% by weight may not give sufficient thermal shock resistance, while a blending amount of more than 10% by weight may reduce mechanical strength.

In the composition of the present invention, a release agent such as carnauba wax, higher fatty acid or synthetic wax, if necessary,
Further, a silane coupling agent, antimony oxide, a phosphorus compound or the like may be added.

The composition of the present invention can be produced by melt-kneading the above-mentioned components with a heating roll, melt-kneading with a kneader, and melt-kneading with a continuous extruder. There is no particular limitation on the order of mixing the components.

The thermosetting resin composition of the present invention thus obtained is a DIP type, a flat pack type, a PLCC type, an S type.
It is effective for semiconductor packages such as O type, and in this case, a molding method conventionally used, for example, transfer molding,
It can be performed by employing injection molding, casting method or the like. The thermosetting resin composition of the present invention has a molding temperature of 150 to 180 ° C. and a post cure of 150 to 185.
It is preferable to carry out at 2 ° C for 2 to 16 hours.

[0060]

EFFECTS OF THE INVENTION The thermosetting resin composition of the present invention gives a cured product having good fluidity, a small expansion coefficient, a high glass transition temperature, good heat resistance and low hygroscopicity. .. Furthermore, the semiconductor device sealed with the cured product of the composition of the present invention has extremely high reliability.

[0061]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

[Examples and Comparative Examples] In addition to the components shown in Table 1, 550 parts of spherical silica, 10 parts of antimony trioxide, γ
-Glycidoxypropyltrimethoxysilane 1.5 parts,
Eight types of thermosetting resin compositions were prepared by adding 1.5 parts of wax E, 1.0 part of carbon black and 0.8 parts of triphenylphosphine, and uniformly kneading the resulting mixture with a hot double roll. Was manufactured (Examples 1 to 5, Comparative Examples 1 to 3).

The following various characteristics (a) to (e) of these epoxy resin compositions were measured. The results are shown in Table 1. (A) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the condition of g / cm ² . (B) Mechanical strength (flexural strength, flexural modulus) 175 ° C, 70 kg / c according to JISK6911
The measurement was performed by molding a bending bar of 10 × 100 × 4 mm under conditions of m ² and a molding time of 2 minutes and post-curing at 180 ° C. for 4 hours. (C) 4 under the conditions of glass transition temperature, expansion coefficient of 175 ° C., 70 kg / cm ² , and molding time of 2 minutes.
It was measured by molding a test piece of × 4 × 15 mm, post-curing at 180 ° C. for 4 hours, and raising the temperature at 5 ° C./min with a dilatometer. (D) Moisture absorption after moisture absorption and solder cracking and moisture resistance A semiconductor device for moisture resistance test for aluminum wiring corrosion measurement into a flat package with a thickness of 2 mm under the conditions of 175 ° C, 70 kg / cm ² and molding time of 2 minutes. It was sealed and post-cured at 180 ° C. for 4 hours. This package is 85 ℃ /
After being left in an atmosphere of 85% RH for 120 hours to perform a moisture absorption treatment, the amount of moisture absorption was measured, and this was placed in a solder bath at 260 ° C for 1 hour.
It was immersed for 0 seconds. After confirming the number of package cracks generated at this time, only non-defective products were allowed to stand in a saturated steam atmosphere at 120 ° C. for a predetermined time, and the defect occurrence rate was examined. (E) Heat-resistant reliability A silicon chip provided with aluminum wiring was bonded to a 14-pin 42 alloy frame with an epoxy resin, and then an integrated circuit in which a lead and an aluminum wiring were connected with a gold wire was sealed with the epoxy resin composition. .. The molding conditions were 175 ° C. for 2 minutes and the post cure was 180 ° C. for 5 hours. The obtained integrated circuit was allowed to stand at 200 ° C. for 500 hours, and then the resistance was measured. When the resistance value was 10Ω or more due to the intermetallic compound formed at the gold-aluminum joint, the failure rate was determined. Examined.

[0064]

[Table 1] *, **: The following were used as epoxy resin and phenol resin.

[0065]

[Table 2]

[0066]

[Chemical 16]

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area H01L 23/29 23/31

Claims (2)

[Claims] 1. A naphthalene ring-containing epoxy resin containing (a) a compound represented by the following formula (1) in an amount of 10% by weight or less: (However, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, OG is a glycidyl group, n is 1 or 2, and may be added to any ring of the naphthalene ring, and may be added to both rings at the same time. (B) A naphthalene ring-containing phenol resin in which the content of the compound represented by the following formula (2) is 10% by weight or less. (However, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, n is 1 or 2, and may be added to any ring of the naphthalene ring, or may be added to both rings at the same time. ) (C) Inorganic filler, and the content of the compounds of the formulas (1) and (2) is 10% by weight or less based on the total amount of the resin. object. 2. A semiconductor device encapsulated with the cured product of the thermosetting resin composition according to claim 1.