JPH0765032B2 - Sealant composition comprising vinylphenylglycidyl ether polymer and curing agent - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a composition having excellent properties such that an internal stress is relaxed and a glass transition temperature is high in an encapsulating resin material for encapsulating a semiconductor integrated circuit.

A resin material for encapsulating a semiconductor integrated circuit is required to have various strict physical properties in order to protect the semiconductor integrated circuit from the external environment.

Important among these requirements are reduction of internal stress and high glass transition temperature. Internal stress causes cracks in the resin part that occur when the environment of the molded encapsulant changes many times between low and high temperatures, and stress that acts on the integrated circuit due to internal stress. There is. In the rubber region above the glass transition temperature, the molecular motion of the resin causes
The price of electrical insulation performance is fixed. In order to reduce the internal stress, generally, there is a method of lowering the crosslink density, but since the glass transition temperature is also lowered by this method, it is extremely difficult to obtain a composition that satisfies the above two required physical properties. is there. As an alternative method, a method of compounding dispersed particles of rubber has been devised, but the rubber has not been put into practical use due to thermal deterioration at high temperatures and adverse effects such as impurities contained in the rubber.

The inventor of the present invention has arrived at the present invention as a result of earnest research on a resin composition for encapsulation satisfying contradictory physical properties such as relaxation of internal stress and high glass transition temperature. That is, the present invention relates to a glycidyl ether of a polyhydric phenol having the general formula (I) (However, R ₁ is a group selected from hydrogen, a methyl group, and an ethyl group, and R ₂ is a group selected from hydrogen, an alkyl group having 1 to 10 carbon atoms, and a halogen atom.) The present invention relates to a composition for a sealant, which comprises a vinylphenyl glycidyl ether polymer having a number average degree of polymerization of 3 to 50 and a curing agent.

The characteristics of the composition of the present invention are as follows. That is, a polymer of vinylphenyl glycidyl ether is used as the glycidyl ether of polyhydric phenol which is the main component of the curing composition. The glycidyl ether of cresol novolac, which has been conventionally used as the main component of the composition for sealing integrated circuits, has a structure in which phenyl nucleus units are linked via a methylene chain. The structure is a structure in which the molecular motion is suppressed, in other words, it is a very rigid molecular structure.

In contrast, the vinyl phenyl glycidyl ether polymer of the present invention has a structure in which phenyl glycidyl ether is bonded to a polyethylene chain. In this structure, the restriction on the molecular motion of the polyethylene chain is reduced.

The present inventor has paid close attention to these points and, as a result of extensive studies, has found that the composition of the present invention has the following excellent characteristics.
First, the elastic modulus, which has a welding relationship with the internal stress generation, decreases. That is, the internal stress is expressed by the general formula (II) (Α is an internal stress, K is a constant, E is a modulus of elasticity of a matrix, α ₂ and α ₁ are linear expansion coefficients of a matrix and a substrate (in the present invention, an integrated circuit element), T is temperature, and To is Is a reference temperature.), And it is suggested that the internal stress can be lowered by lowering the elastic modulus according to the general formula (II). Further, the glass transition temperature is higher than that in the case where the glycidyl ether of cresol novolac is used as the main component. The reason for this is as follows.

From the theory of rubber elasticity, the crosslink density and elastic modulus are expressed by the general formula (II
Expressed as I).

E = 2RTX (III) (E is the elastic modulus, R is the gas constant, T is the absolute temperature, and X is the crosslink density.) The cured molded article containing the vinylphenyl glycidyl ether polymer of the present invention as the main component has a glass transition. The elastic modulus in the rubber region above the temperature is higher than that of glycidyl ether of gresol novolac. Therefore, the general formula (III) suggests that the crosslink density is high. As a result, it is estimated that the glass transition temperature was increased.

As described above, the composition of the present invention has an excellent property that a molded product having a low internal stress and a high glass transition temperature, which is impossible with the conventional composition, can be produced.

The polymerized units of the vinylphenol glycidyl ether polymer of the present invention have a number average degree of polymerization of 3 to 50.

When the number average degree of polymerization is 3 or less, the glass transition temperature becomes low. Further, when the number average degree of polymerization is 50 or more, the viscosity at the time of processing is high and the workability and moldability are deteriorated. The polymerized units represented by the general formula (I) may be the same or a combination of different units, but it is not a particularly important factor. When R ₂ is a bromine atom, the composition has a flame retardant effect.

The vinyl phenyl glycidyl ether polymer of the present invention can be produced by the following method. For example, as described in Organic Synthetic Chemistry Vol. 26, No. 12, page 1102 (Showa 43), vinyl phenyl glycidyl ether is synthesized from vinyl phenol and epichlorohydrin, and then vinyl phenyl glycidyl ether is polymerized by radical polymerization. The polymer can be obtained. In addition, another method described in the same document, that is, after polymerizing vinylphenol into a high molecular weight by radical polymerization, a polymer of vinylphenylglycidyl ether can be obtained from the polymer and epichlorohydrin.

Specific examples of the curing agent used in the composition of the present invention include:
Novolak type phenols such as phenol novolac, m-cresol novolac and resorcin novolac, vinylphenols such as vinylphenol polymers and isopropenylphenol polymers, triethylenetriamine, triethylenetetramine, tetraethylenepentamine, dimethylaminopropylamine, Aliphatic amines such as diethylaminopropylamine, aminoethylethanolamine, alicyclic amines such as menthanediamine, n-aminoethylpiperazine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, metaxylenediamine, metaaminobenzylaminebenzidine , 4-chloro-o-phenylenediamine, bis (3,4-diaminophenyl) sulfone, 2,6-
Aromatic amines such as diaminopyridine, polyamide resins, pyromellitic anhydride, succinic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, methylnadic acid anhydride, glutaric anhydride, tetrabromophthalic anhydride, etc. Among the acid anhydrides, novolac type phenols such as phenol novolac and m-cresol novolac, vinylphenols such as vinylphenol polymer and isopropenylphenol polymer are preferable. At this time, an inorganic filler such as silica, alumina, talc, clay, or glass fiber, a curing accelerator such as imidazoles or tertiary amines, an internal release agent such as stearic acid, calcium stearate, carnauba wax, or montan wax. Usually compounded. The composition is generally used as an encapsulant composition when encapsulating a semiconductor integrated circuit by transfer molding. The composition ratio of the composition varies depending on each type,
As a general rule, the amount of the curing agent is such that the number of moles of the functional groups of the curing agent is the same as the number of moles of the epoxy groups of the vinyl phenyl glycidyl ether polymer, and the amount of the filler is The compounding amount is such that it is close to the closest packing, the curing accelerator is used in a catalytic amount, and the internal release agent is used in an amount of about 0.2 to 2.0% by weight based on the total compounding amount.

The present invention will be described below with reference to examples, but the present invention is not limited to the examples. The epoxy equivalent in the present invention is defined as gram equivalent per mol of glycidyl ether group. Hydrolyzable chlorine is a glycidyl ether of polyhydric phenol dissolved in dioxane, added with an alcohol solution of potassium hydroxide and desorbed when heated at reflux for 30 minutes. It is defined by the weight percentage of chlorine atoms in the inside.

The viscoelastic properties of the cured moldings in Examples and Comparative Examples were measured according to “Viscoelasticity of Polymer” (John D. Ferry, translated by Hiroshi Sobue, published by Tokyo Kagaku Dojin).

Reference Example 1 A thermometer, a separating tube, a dropping funnel, and a stirrer were attached 1
Parachlorophenol polymer (1.0 mol equivalent as phenolic hydroxyl group) was added to the flask using epichlorohydrin.
Dissolve in 7.0 mol. Keeping the temperature at 64 ℃ and the pressure at 150mmHg, 6
48% aqueous NaOH solution was added continuously over time. During this time, epichlorohydrin and water were azeotropically liquefied to be liquefied and separated into an organic layer and an aqueous layer by a separation tube, the aqueous layer was removed outside the system, and the organic layer was circulated inside the system. After completion of the reaction, the temperature was kept for 1 hour to evaporate and remove unreacted epichlorohydrin, and the reactive product was dissolved in methyl isobutyl ketone. Next, after removing the by-product salt, methyl isobutyl ketone was evaporated and removed to obtain a solid resin at room temperature.

The glycidyl ether of the polymer has a number average degree of polymerization of 13
The epoxy equivalent was 221 and the hydrolyzable chlorine content was 0.05 wt%.

Reference Example 2 In a 10 L glass lining container equipped with a stirrer, dry N ₂ gas was passed to drive out O ₂ , and anhydrous methylene chloride (21) and paraisopropenylphenol (2 mol) were charged and dissolved therein.

After this solution was cooled to -40 ° C, 0.02 mol of boron trifluoride ethyl ether complex (5% hexane solution) was added and a polymerization reaction was carried out for 5 hours, and 1 L of methanol was added to stop the reaction.

The reaction solution was washed with pure water to remove water-soluble components, and then volatile components were evaporated to obtain a polymer of paraisopropenylphenol.

Subsequently, the paraisopropenylphenol polymer was glycidyl etherified in the same manner as in Reference Example 1.

The glycidyl ether had an average degree of polymerization of 11, an epoxy equivalent of 230, and a hydrolyzable chlorine content of 0.05 wt%.

Reference Examples 3 and 4 By the same method as in Reference Example 1, polymers of para-vinylphenylglycidyl ether having different degrees of polymerization were obtained.

The glycidyl ether of Reference Example 3 has a number average degree of polymerization of 4
The epoxy equivalent was 220 and the amount of hydrolyzable chlorine was 0.05 wt%.

The glycidyl ether of Reference Example 4 has a number average degree of polymerization of 46.
The epoxy equivalent was 231 and the hydrolyzable chlorine was 0.05 wt%.

Examples 1 and 2 The physical properties of the vinylphenyl glycidyl ether polymers obtained in Reference Examples 1 and 2 were measured as the main components of Examples 1 and 2 by curing and molding the curable composition in the following manner. .

1.0 mol of the main agent (as an epoxy group, 2 in the case of Reference Example 1)
21g, 228g for Reference Example 2) and phenol novolac
With 1.0 mol (as phenolic hydroxyl group) and curing accelerator
Then, 0.8 parts by weight of Tris is added to the total weight of the main agent and the curing agent.
Dimethylaminomethylphenol (Sumitomo Chemical Co., Ltd.
Company, Sumicure D) is roll-kneaded into a composition
It was Next, this composition is pressed and heated to a 1 mm screen.
Molded. This molding was post-cured at 170 ° C for 5 hours
To produce a cured molding. Viscoelasticity of the cured molded product of Example 1.
The measurement results are shown in FIG. 1 (solid line). Curing molding of Example 2
The product also exhibits similar viscoelastic behavior, but the temperature at the peak point of the main dispersion
The degree (glass transition temperature) is 213 ° C. in the case of Example 1.
In the case of Example 2, the temperature was 211 ° C.

Examples 3 and 4 Cured molded articles were prepared in the same manner as in Examples 1 and 2, and viscoelasticity was measured. Examples 3 and 4 also exhibited the same viscoelastic behavior as that of Example 1. The glass transition temperature of each of Examples 3 and 4 was 210.
It was ℃ and 215 ℃.

Comparative Example 1 Commercially available cresol novolac glycidyl ether
Sumiepoxy manufactured by Tomo Chemical Co., Ltd. ESCN-220)
As the agent, a cured molded product is prepared in the same manner as in Example 1.
It was The viscoelasticity measurement results of this molded product are shown in Fig. 1 (dots).
line).

Compared to Comparative Example 1, in Example 1, the peak of sub-dispersion on the low temperature side is shifted to a low temperature, and the elastic modulus also decreases near this temperature, showing typical stress relaxation behavior. Also about
A new sub-dispersion appears from around 100 ° C to the peak of the main dispersion, and exhibits the stress relaxation behavior as described above. Further, in the rubber region of 250 ° C., the elastic modulus is about 1 × 10 ⁹ dyn / cm ² in the case of Comparative Example 1, whereas it is 4 × 10 ⁹ dyn / cm ^{2 in} Example 1, which is the invention. It suggests that the crosslink density is high as described in the detailed description of.

The viscoelastic behavior of FIG. 1 will be described in detail. Comparative Example 1
Has a glass transition temperature of 197 ° C, but above this temperature, molecular motion of the network structure formed by crosslinking occurs. That is, the cured molded product is in a rubber state. This results in a significant reduction in electrical insulation performance as described above. Therefore, it is desirable that the glass transition temperature is as high as possible.
In this respect, the glass transition temperature of Example 1 was 213 ° C., which was 15 ° C. higher than that of Comparative Example 1, and thus the semiconductor integrated circuit was exposed to a higher temperature range from the external environment when used as the encapsulant composition. Can be protected. Generally, the elastic modulus increases as the glass transition temperature is raised, but as is clear from FIG. 1, Example 1 has an excellent feature that the elastic modulus decreases conversely.

Comparative Example 2 A polymer of para-vinylphenol having a higher molecular weight than that of Reference Example 1 was used as a raw material, and a polymer of para-vinylphenylglycidyl ether synthesized by the same method as in Reference Example 1 was used. An attempt was made to make a cured molding.
Since the number average degree of polymerization of the polymer was as high as 62, blending by roll kneading was impossible, and no further study was possible.

Comparative Example 3 A glycidyl ether of a polymer of paraisopropenylphenol was obtained in the same manner as in Reference Example 2 except that the polymerization temperature was 30 ° C.

The glycidyl ether had an average degree of polymerization of about 2.

Using the glycidyl ether, a cured molded product was obtained in the same manner as in Example 1.

The glass transition temperature of the molded product was 179 ° C.

An object of the present invention is to provide a composition having a low internal stress and a high glass transition temperature. In this respect, Comparative Example 3 has a lower glass transition temperature than Comparative Example 1, which is a typical example of the composition currently used on the market, and does not satisfy the object of the present invention.

[Brief description of drawings]

FIG. 1 shows the measurement results of the viscoelastic properties of the cured molded products of Example 1 and Comparative Example 1. The horizontal axis is the temperature when measuring viscoelasticity, the left side of the vertical axis is the dynamic elastic modulus,
The right side of the vertical axis shows tan δ. The solid line shows the measurement results of the cured molded article of Example 1, and the dotted line shows the measurement results of Comparative Example 1. The upper solid line and dotted line indicate the dynamic elastic modulus, which is simply expressed as elastic modulus in the text. The lower solid and dotted lines indicate tan δ. The peak of tan δ near −70 ° C is called subdispersion and is attributed to the micromotion of the molecule. The peak of tan δ near 200 ° C is called main dispersion and is attributed to the motion of the whole molecule, and the temperature at the peak point of tan δ is called the glass transition temperature. From this point, the transition to the rubber region occurs through the transition region. In Comparative Example 1, the rubber region appears from around 240 ° C., but in Example 1, it does not reach the rubber region even at 250 ° C. Since measurement at 250 ° C. or higher was impossible on the apparatus, the value at 250 ° C. was taken as the value of the dynamic elastic modulus of the rubber region in Example 1.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriaki Saito 5-1 Sokai-cho, Niihama-shi, Ehime Sumitomo Chemical Co., Ltd. (72) Inventor Tadashi Ikushima 5-1 Sokai-cho, Niihama-shi Ehime Within the corporation (56) References Japanese Patent Laid-Open No. 56-152831 (JP, A)

Claims (1)

[Claims] 1. In the glycidyl ether of polyhydric phenol, the compound represented by the general formula (I) (However, R ₁ is a group selected from hydrogen, a methyl group, and an ethyl group, and R ₂ is a group selected from hydrogen, an alkyl group having 1 to 10 carbon atoms, and a halogen atom.) A composition for a sealant, comprising a vinylphenyl glycidyl ether polymer having a number average degree of polymerization of 3 to 50 and a curing agent.