JPH04164917A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition which is improved in flow and can give a cured product having a high glass transition temperature, a low coefficient of expansion, low stress and excellent adhesiveness and hygroscopic resistance by mixing a specified epoxy resin with a phenolic resin. CONSTITUTION:0-95 pts.wt. epoxy resin optionally having at least one (un) substituted naphthalene ring in the molecule and at least two epoxy groups in the molecule is mixed with 100-5 pts.wt. epoxy resin of the formula (wherein R is H, halogen or a 1-5C monovalent hydrocarbon group; and n is 0-5) to obtain an epoxy resin(A). Component A is mixed with a phenolic resin (B) optionally having at least one (un)substituted naphthalene ring in the molecule in an amount to give a molar ratio of the epoxy groups of component A to the phenolic hydroxyl groups of component B of 0.5-1.5 to obtain the title composition wherein part or all of components A and/or B have naphthalene rings.

Description

[Detailed Description of the Invention] The present invention has good fluidity, a small coefficient of expansion, a high glass transition temperature, low stress, and has good adhesive properties and low stress. The present invention relates to an epoxy resin composition that provides a cured product with excellent hygroscopicity, and a semiconductor device sealed with the cured product of this epoxy resin composition.

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Currently, resin-encapsulated diodes, transistors, ICs, LSIs, and VLSIs are the mainstream in the semiconductor industry, and in particular, curable epoxy resins, curing agents, and epoxy resins containing various additives are used. Semiconductor devices are often encapsulated with epoxy resin compositions because the compositions generally have better moldability, adhesiveness, electrical properties, mechanical properties, moisture resistance, etc. than other thermosetting resins. It is.

Recently, the degree of integration of these semiconductor devices has been increasing, and the chip size has also been increasing accordingly.
On the other hand, package external dimensions are becoming smaller and thinner due to the demand for smaller and lighter electronic devices. Furthermore, in the method of attaching semiconductor components to a circuit board, surface mounting of semiconductor components has become common due to the higher density of components on the board and the thinner board.

However, when surface mounting a semiconductor device onto a circuit board, it is common to immerse the entire semiconductor device in a solder bath or pass it through a high-temperature zone where the solder melts, but the thermal shock caused by this process results in sealing. There were problems such as cracks occurring in the resin layer and peeling occurring at the interface between the lead frame or chip and the sealing resin. Such racking and peeling become more noticeable if the encapsulation resin layer of the semiconductor device absorbs moisture before the thermal shock during surface mounting.
In the actual work step S:, moisture absorption in the sealing resin layer is unavoidable, and as a result, the reliability of the semiconductor device sealed with the epoxy resin after mounting may be greatly impaired.

Therefore, it has been desired to develop a high-quality epoxy resin composition for encapsulating a semiconductor device that can provide a semiconductor device with high reliability after surface mounting on a circuit board.

The present invention was developed in view of the above circumstances, and provides a cured product that has good fluidity, a high glass transition temperature, a small coefficient of expansion, low stress, and excellent adhesiveness and low moisture absorption. An object of the present invention is to provide an epoxy resin composition and a semiconductor device sealed with a cured product of the epoxy resin composition that has high reliability even after thermal shock during surface mounting.

In order to achieve the above object, the inventors of the present invention have made extensive studies to achieve the above object, and have found that (a) an epoxy resin having at least two epoxy groups in one molecule, and (b) a compound of the following general formula (I ) (However, in the formula, R is a hydrogen atom, a halogen atom, or a carbon number 1
-5 monovalent hydrocarbon group, n is an integer of 0-5. ) and the epoxy resin shown in the weight ratio (a)/(b)=
Contains a mixed epoxy resin and a phenol resin as a curing catalyst in a ratio of 0 to 95/1oo to 5, and
An epoxy resin composition in which part or all of the above yupoxy tree D (a) and/or phenol resin has at least one substituted or unsubstituted naphthalene ring in one molecule has good fluidity and To provide a cured product with excellent low stress properties, which has characteristics such as a small expansion coefficient, excellent adhesiveness, and a decrease in elastic modulus in the temperature range above the glass transition temperature. The epoxy resin composition obtained by this method had drawbacks such as a lower glass transition temperature and insufficient resin strength, but the above epoxy resin composition has a lower glass transition temperature while having a low elastic modulus. The inventors have discovered that this method provides a cured product that has excellent properties that are not available with conventional epoxy resin compositions, such as no moisture absorption and low hygroscopicity. In addition, a semiconductor device sealed with such a cured product has high reliability even after thermal shock during surface mounting, and for this reason, the above-mentioned epoxy resin composition is used for SOP type and SOJ type.

It was discovered that it can be used for encapsulating any type of semiconductor device such as PLCC type or flat punk type, and has very excellent properties as a encapsulating material for surface-mounted semiconductor devices in particular, and the present invention I came to do this.

Therefore, the present invention provides (1) (a) an epoxy resin having at least two epoxy groups in one molecule, and (b) an epoxy resin represented by the above general formula (1) in a weight ratio of (a)/ (b)=O~9
An epoxy resin mixed in a ratio of 5/100 to 5, and (2) a phenol resin, and a part or all of the epoxy resin (a) and/or the phenol resin has a substituted or unsubstituted naphthalene ring. Provided are an epoxy resin composition having at least one epoxy resin in one molecule, and a semiconductor device sealed with a cured product of the epoxy resin composition. - The present invention will be explained in more detail below.

The epoxy resin composition of the present invention comprises (a) an epoxy resin having at least two epoxy groups in one molecule, and (b) an epoxy resin represented by the above formula (1) as the first essential epoxy resin. Mix in specific proportions.

Here, as the epoxy resin of component (a), any currently commercially available epoxy resin having at least two epoxy groups in one molecule can be used, but in particular, substituted or unsubstituted epoxy resins in one molecule can be used. It is preferable to use an epoxy resin having at least one naphthalene ring. By using such an epoxy resin having a naphthalene ring, it is possible to obtain a cured product that has a small expansion coefficient, a high glass transition temperature, low elasticity in a temperature range above the glass transition temperature, and low hygroscopicity. can.

Specific examples of such epoxy resins include compounds having the following structures.

G (In the above formula, R1 represents a hydrogen atom or a carbon number of 1 to 5, m is l or 2, and k, I, and n are each an integer of 2 or more.) Furthermore, the above-mentioned naphthalene ring In addition to the epoxy resin, if necessary, for example, glycidyl ether type epoxy resin such as bisphenol A type evoquine resin, phenol novolac type epoxy resin, allylphenol novolac type epoxy resin, triphenolalkane type epoxy resin and its polymer, biphenyl type. Epoxy resins such as epoxy resin, dicyclopentadiene type epoxy resin, phenol aralkyl type epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, heterocyclic type epoxy resin, halogenated epoxy resin, etc. can be used together. .

In addition, the epoxy resin of component (b) has the following general formula (1)% formula% In this case, the substituent R in formula (1) is a hydrogen atom, a halogen atom (for example, a chlorine atom, a bromine atom, a fluorine atom, etc.) or a monovalent hydrocarbon group having 1 to 5 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, dipentyl group, etc.),
n is an integer from 0 to 5.

Specifically, as such an epoxy resin of formula (1),
Compounds having the following structures can be mentioned.

(In the above formula, nl-0~5.nz =O~5゜n, +n
, =O~5. ) In the present invention, the epoxy resin of the component (a) described above as the first essential component and the epoxy resin represented by the formula (I) of the component (b) are used in a weight ratio of (a)/(b) of 0 to 95. /100
~5, preferably 1-95/99-5, especially 30-90
/70 to 1o. Therefore, although it is possible to use only the epoxy resin of the formula (1) of the component (b) as the epoxy resin, it is possible to use a mixture of the components (a) and (b) to improve the adhesive properties. It is possible to obtain an epoxy resin composition that has excellent properties, a high glass transition temperature, and provides a cured product that has flexibility even below the glass transition temperature. Note that if the content of component (b) is less than the above ratio, the expected effects on the reliability of the semiconductor device, such as the adhesiveness of the cured product, crack resistance during surface mounting, and moisture resistance after mounting, may not be obtained. There is.

Next, the second essential component, phenolic resin, acts as a curing agent for epoxy resins, such as novolac type phenolic resin, resol type phenolic resin, phenol aralkyl resin, triphenol alkane type resin, and polymers thereof. However, in the present invention, it is particularly preferable to use a phenol resin having at least one substituted or unsubstituted naphthalene ring in one molecule as the second essential component.

Here, specific examples of the phenol resin having a naphthalene ring include compounds having the following structures.

i・, R・, ′ j+8 H (However, R′, 1, m each have the same meaning as above, and p is an integer of 1 or more.) The above phenol resin having a naphthalene ring is It may be blended as a part of the phenolic resin, which is the second essential component, or may be blended in its entirety.

Furthermore, in addition to the above-mentioned phenol resin, the composition of the present invention contains diaminodiphenylmethane and diaminodiphenylsulfone as other curing agents.

Amine curing agents typified by metaphenylene diamine, acid anhydride curing agents such as phthalic anhydride, pyromeria anhydride, benzophenone tetracarboxylic anhydride, etc. can also be used in combination within the range that does not impede the effects of the present invention. .

Therefore, the epoxy resin composition of the present invention contains the above-mentioned epoxy resin and phenol resin as essential components, but part or all of the epoxy resin and/or phenol resin as component (a) above. must have at least one substituted or unsubstituted naphthalene ring in one molecule.

In this case, the content of naphthalene rings in the epoxy resin as component (a) and the phenol resin as a curing agent is 5
The range is preferably from 10 to 60% by weight, particularly from 10 to 60% by weight. If the naphthalene ring content is less than 10% by weight, the cured product will have low moisture absorption, and the effect of lowering the elastic modulus in the temperature range above the glass transition temperature will not be noticeable, resulting in poor crack resistance during thermal shock after moisture absorption. may not be improved sufficiently.

Furthermore, if the naphthalene ring content exceeds 80% by weight, it may be disadvantageous in terms of dispersibility or moldability during production.

Further, in the present invention, the ratio (A/B) between the amount of epochino groups (A mol) and the amount of phenolic hydroxyl groups (B mol) contained in the composition is 0.5 to 1.5, particularly 0.5 to 1.5. It is preferable to mix the epoxy resin and phenol resin so that the ratio is in the range of 8 to 1.2, and if A/B is outside the above range, it may be disadvantageous in terms of curability and low stress properties.

It is preferable to mix an inorganic filler into the epoxy resin composition of the present invention.

Here, as the inorganic filler, those usually blended into epoxy resin compositions can be used, such as silicas such as fused silica and crystalline silica, alumina, carbon bra, silica, etc.
Examples include mica, clay, kaolin, glass peas, glass fiber, AffiN, 5iC1 zinc white, antimony trioxide, lunoium carbide, aluminum hydroxide, Bed, poron nitride, titanium oxide, silicon carbide, iron oxide, etc. . One type of these inorganic fillers can be used alone, or two or more types can be used in combination.The blending amount is not particularly limited, but the epoxy resin as the first component and the phenol resin as the second component can be used in combination. It is preferably in the range of 100 to 1000 parts, particularly 200 to 700 parts, based on 100 parts (parts by weight, hereinafter) of the total amount.

Furthermore, a curing catalyst can be added to the composition of the present invention.

As a curing catalyst, for example, 1,8-diazabicyclo(5
,4,O) Tertiary amine compounds such as undecene-7,N,N-dimethylhensylamine, imidazole compounds such as 2-phenylimidazole and 2-ethyl-4-methylimidazole, and phosphorus such as triphenylphosphine. Examples include 1,8-diazabicyclo(5
, 4゜0) Undecene-7 and triphenylphosphine in a weight ratio of 0:1 to 1:l, especially 0.01:1 to o,s
It is preferable to use a combined catalyst mixed in a ratio of :i. If the mixing ratio of 1,8-diazabicyclo(5,4°0)undecene-7 is outside the above range, the glass transition temperature of the resulting cured product may become low.

Further, the amount of the curing catalyst added is not particularly limited, but when using the above-mentioned combined catalyst, 0.00 parts per 100 parts of the total amount of the epoxy resin as the first component and the phenol resin as the second component.
It is desirable to use 2 to 2 parts, particularly 0.4 to 1.2 parts.

In addition to the above-mentioned essential components, the composition of the present invention may further contain various additives as other optional components, if necessary. Optional ingredients include, for example, thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers, low stress agents such as silicone, one laths such as carnauba wax, mold release agents such as fatty acids such as stearic acid and their metal salts, and carbon black. , cobalt blue, pigments such as Hengara, antimony oxide, flame retardants such as halogen compounds, surface treatment agents (T-glycidoxypropyltrimethquinsilane, etc.)
, Evokinran, vinyl silane, boronate compounds, coupling agents such as alkyl titanates, anti-aging agents, and other additives.One or more types of additives may be blended.

Incidentally, the amount of these additives to be blended can be a normal amount within a range that does not impede the effects of the present invention.

The epoxy resin composition of the present invention is manufactured by uniformly stirring and mixing the above-mentioned components in predetermined amounts, and preliminarily preparing the epoxy resin composition with a 70 to 90%
It can be obtained by heating to °C, kneading with a kneader, roll, extruder, etc., cooling, and pulverizing. Here, there is no particular restriction on the order of blending the components.

The epoxy resin composition of the present invention thus obtained can be effectively used for sealing semiconductor devices such as SOP type, SOJ type, PLCC type, flat pack type, etc. In this case, molding is conventionally employed. This can be carried out by employing various molding methods such as transfer molding, injection molding, and casting. The epoxy resin composition of the present invention is desirably molded at a temperature of 150 to 180°C, and post-cured at 150 to 180°C for 2 to 16 hours.

As explained above, the epoxy resin composition of the present invention
By combining the above-mentioned components, a cured product with good fluidity, low elastic modulus, small expansion coefficient, low stress, high glass transition temperature, low hygroscopicity, and excellent adhesiveness. Therefore, a semiconductor device sealed with a cured product of the epoxy resin composition of the present invention has high reliability even after thermal shock during surface mounting.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.

In addition, in the following examples, all parts are parts by weight.

[Examples 1 to 8, Comparative Example 1.2] In addition to the composition shown in Table 1, 10 parts of antimony dioxide, T
- 1.5 parts of glycytoquinoprobil trimethoquinonolane,
10 parts carbon blank, triphenylphos 74706
8 parts and 500 parts of molten liquor were added thereto, and the resulting mixture was uniformly melt-mixed using a thermonikki roll to obtain 10 types of epoxy resin compositions.

When these epoxy resin compositions become sticky, the following (a)
The various characteristics of ~(e) were measured. The results are shown in Table 1.

(A) 175'C2 using a mold that complies with the EMM I standard.
Measurement was performed under the condition of 70 kg/cn.

(b) Mechanical strength (bending strength, bending modulus) JISK6
911, a 10×100×4++o anti-deflection rod was molded under the conditions of 175° C., 170 kg/all, and molding time of 2 minutes, and was post-cured at 180° C. for 4 hours.

(c) Glass transition temperature, expansion coefficient 175°C, 110kg/ci, molding time 2 minutes 4
A test piece of X4X15 size was molded and post-cured at 180°C for 4 hours, and the temperature was raised at 5°C per minute using a deiradometer.

(d) “Island”’s Ku Libigo 175°C1
Semiconductor device for moisture resistance test for aluminum wiring corrosion measurement under the conditions of 70 kg/CTA and 2 minutes of molding time with a thickness of 21!
Sealed in a ll11 flat package and heated at 180'C.
I post cured it for 4 hours. This bar.

After the cage was left in an atmosphere of 85°C/85% RH for 72 hours to absorb moisture, it was immersed in a solder bath at 260°C for 10 seconds. After confirming the number of pan cage cranks that occurred at this time, only non-defective products were left in a saturated steam atmosphere at 120''C for 500 hours, and the failure rate was investigated.

(E) One cylindrical molded product with a diameter of 15 mm and a height of 5 mm is placed on an IL-resistant 4270 plate.
It was molded under the conditions of 75°C, 175kg/c++1, and molding time of 2 minutes, and after post-curing at 180°C for 4 hours, the peel force between the molded product and the 4270 plate was measured using a bush pre-gauge.

From the results in Table 1, the epoxy resin compositions of the present invention (Examples 1 to 8) have good fluidity, a small expansion coefficient, and low stress. It was confirmed that the cured product had a high glass transition temperature, low hygroscopicity, and excellent adhesiveness. On the other hand, epoxy resin compositions that do not contain naphthalene ring-containing epoxy resins or phenol resins (Comparative Examples 1 and 2) have large expansion coefficients, and are insufficient to reduce stress at temperatures higher than the glass transition temperature. It was also inferior in hygroscopicity and adhesiveness.

Applicant: Shin-Etsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. (1) (a) At least two epoxy groups in one molecule
(b) The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(I
) (However, in the formula, R is a hydrogen atom, a halogen atom, or a carbon number 1
-5 monovalent hydrocarbon group, n is an integer of 0-5. ) and the epoxy resin shown in the weight ratio (a)/(b)=
Epoxy resin mixed in a ratio of 0 to 95/100 to 5,
and (2) contains a phenol resin, and part or all of the epoxy resin (a) and/or the phenol resin has at least one substituted or unsubstituted naphthalene ring in one molecule. Characteristic epoxy resin composition. 2. A semiconductor device sealed with a cured product of the epoxy resin composition according to claim 1.