JPH06256475A - Epoxy resin composition for photosemiconductor element sealing - Google Patents

Abstract

PURPOSE:To provide a photosemiconductor device excellent in resistance to humidity and thermal shock and significantly improved in transparency. CONSTITUTION:The objective composition comprises an epoxy resin, a bisphenolic novolak, a curing accelerator, and at least one of an organophosphorus compound, a thioether, and a hindered phenol.

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 suitable for optical semiconductor devices having excellent humidity resistance, thermal shock resistance reliability and transparency.

[0002]

2. Description of the Related Art Epoxy resin compositions are generally used as a sealing material for optical semiconductor elements such as light emitting elements and light receiving elements, from the viewpoint of excellent transparency, heat resistance and electrical characteristics. At this time, an acid anhydride is often used as a curing agent because of its excellent transparency and moldability.

[0003]

However, when an acid anhydride is used as a curing agent, the moisture resistance and thermal shock resistance of the cured product are insufficient. On the other hand, when phenol novolac is used, it has excellent moisture resistance and thermal shock resistance,
It has the drawback of being markedly colored by heat. An object of the present invention is to provide an optical semiconductor device which is excellent in moisture resistance reliability and thermal shock resistance reliability and whose transparency is remarkably improved.

[0004]

That is, the present invention is as follows.
(A) Epoxy resin, (B) Bisphenol-based novolac resin, (C) Curing accelerator, and epoxy resin composition for optical semiconductor element encapsulation containing at least one of the following components (D) to (F) Is. (D) Organophosphorus compound (E) Thioether compound (F) Hindered phenol compound The present inventors focused their attention on a phenol novolac resin excellent in moisture resistance and thermal shock resistance, and conducted a series of researches for preventing coloring due to heat. During the process, I thought that the molecular structure of the phenol novolac resin may have a structure that is prone to thermal oxidation, and proceeded with this research. As a result, it was found that when the above bisphenol novolac resin is used, thermal oxidation is unlikely to occur and coloring of the cured product due to heat is reduced. Furthermore, they have found that the use of several kinds of compounds known as antioxidants in combination causes almost no coloration of the cured product, and has reached the present invention.

The epoxy resin (component A) used in the present invention is not particularly limited, but it is preferable that the epoxy resin is less colored in consideration of the optical characteristics of the cured product. Examples thereof include bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin, and heterocyclic epoxy resin containing triglycidyl isocyanurate. , Alone or in combination.

The bisphenol type novolak resin (component B) used in the present invention is synthesized by the same method as that for ordinary phenol novolac resin. That is, bisphenols and formaldehyde are heated in the presence of a catalyst for condensation polymerization, and after the reaction, dehydration gives a bisphenol novolac resin. The bisphenols used in the synthesis of the bisphenol novolac resin are preferably bisphenol A, hydrogenated bisphenol A, bisphenol AF, bisphenol C and bisphenol Z. The formaldehyde source is not particularly limited and includes formalin and paraformaldehyde. The molar ratio of formaldehyde to the phenolic hydroxyl group of bisphenol should be 0.3 to 1.0, preferably 0.5 to 0.7. If the molar ratio is 0.3 or less, a large amount of unreacted bisphenol remains, and the crosslink density and heat resistance of the oxide decrease, and if 1.0 or more, gelation may occur during resin synthesis. The bisphenol-based novolac resin synthesis catalyst is not particularly limited as long as it is a novolac synthesis catalyst. Examples thereof include oxalic acid, hydroxides of alkaline earth metals, acetates, and halides of other metals. The mixing ratio of the epoxy resin and the bisphenol-based novolac resin is 1.
Phenolic hydroxyl group is 0.7 to 2.0 with respect to 0 equivalent.
It is desirable that the equivalent, preferably 0.9 to 1.2 equivalent. If it exceeds this range, the reaction becomes insufficient and the physical properties of the cured product deteriorate.

Curing accelerator used in the present invention (component C)
Examples of the known compound include imidazoles, DBU and salts thereof, tertiary amines, quaternary ammonium salts, and quaternary phosphonium salts. The amount used may be 0.05 to 10%, more preferably 0.1 to 5%, based on the total amount of the epoxy resin and the bisphenol-based novolac resin.

Further, (D) to be used in the present invention
The component (F) is an antioxidant for preventing the epoxy resin and the bisphenol novolac resin from being colored by heat. As these components, those having good compatibility with the epoxy resin and the bisphenol-based novolac resin are particularly preferable.

As the organic phosphorus compound (component D), diphenylisodecyl phosphite, diisodecyl pentaerythritol diisophosphite, 3,9-bis [1,
1-dimethyl-2- {β- (3-tert-butyl-4
-Hydroxy-triphenylphosphite, trisnonylphenylphosphite, tris (2,4-di-ter)
t-Butylphenyl) phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10
-Oxide and the like can be mentioned

As the thioether compound (component E),
Dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, pentaerythritol-tetrakis (β-laurylthiopropionate), tetrakis [methylene-3- (dodecylthio) propionate] Methane, bis [2-methyl-4-
{3-n-myristylthiopropionyloxy} -5-
Examples include tert-butylphenyl] sulfide.

As the hindered phenol compound (F component), 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylene-bis (4-methyl-6-tert-butylphenol), 1 , 3,5-Tris (4-tert-butyl-3-hydroxy-2,6
-Dimethylbenzyl) isocyanurate, tetrakis [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane, 3,9-bis [1,1-dimethyl-2- {Β- (3
-Tert-butyl-4-hydroxy-5-methylphenyl] propionyloxy} ethyl] -2,4,8,1
0-tetraoxaspiro [5.5] undecane, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thiobis (4-methyl-6-
(tert-butylphenol) and the like.

The components (D) to (F) may be used alone, but by using them in combination, a more excellent coloring preventing effect can be obtained. In addition to the above components, a conventionally known release agent, colorant, ultraviolet absorber, visible light absorber, infrared absorber, modifier, inorganic filler, etc. are added to the epoxy resin composition as required. Agents are used.

[0013]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition,
The test methods in the following examples are shown below. (1) Light transmittance Using a spectrophotometer (Hitachi U-2000 type), thickness 2
The light transmittance at a wavelength of 400 to 600 nm was measured for the molded product of mm. (2) Glass transition temperature TMA (TMA-8140 type manufactured by Rigaku Co., Ltd.) was used for a molded product having a diameter of 2 mm and a length of 20 mm, and the temperature was set to a temperature at which the elongation of the molded product suddenly changed when the temperature was raised at 5 ° C / min. . (3) Water absorption rate The weight increase rate when a molded product having a diameter of 50 mm and a thickness of 2 mm was boiled in pure water for 1 hour was used. (4) Moisture resistance reliability test After the evaluation cooker sealed with the above epoxy resin composition (outer dimensions: 20 × 6.3 × 2.3 mm, number of bottles: 16) was processed by the pressure cooker test (PCT) (121 ℃,
(85%) Conduction test was performed, and the broken product was regarded as a defective product. (5) Thermal shock reliability test The same evaluation IC as in (4) was subjected to heat cycle treatment (-
Conductivity test was performed at 40 to 125 ° C. for 30 minutes each, and the broken wire was regarded as a defective product.

Examples 1 and 2 900 g of bisphenol A, 37% formalin 200
g and 9 g of oxalic acid are heated and refluxed for 4 hours under a nitrogen gas flow to react, and then heated at 120 ° C. for 2 hours and concentrated under atmospheric pressure. Further, it was dehydrated under reduced pressure to obtain a bisphenol A novolac resin [A]. This was blended according to the following Table 1, kneaded with a hot roll at 90 ° C. for 10 to 30 minutes, and then cooled and pulverized to obtain a target fine powdery epoxy resin composition. Next, transfer molding of these resin compositions at a molding temperature of 170 ° C. (molding time of 4 minutes) using respective test dies
And further after-cured at 170 ° C. for 3 hours. Table 1 also shows the characteristic results of the various molded products obtained.

[0015]

[Table 1]

Comparative Examples 1 and 2 The respective raw materials were blended in accordance with Table 1, and the ingredients were mixed with a hot roll at 90 ° C.
After kneading for 0 minutes, the mixture was cooled and ground to obtain the desired fine powdery epoxy resin composition. Next, these resin compositions were subjected to transfer molding (molding time: 4 minutes) at a molding temperature of 170 ° C. using each test mold, and after-cured at 170 ° C. for 3 hours. Table 1 also shows the characteristic results of the various molded products obtained.

Comparative Example 3 Each raw material was blended in accordance with Table 1 and heated at 90.degree.
After kneading for 0 minutes, the mixture was cooled and ground to obtain the desired fine powdery epoxy resin composition. Next, these resin compositions were subjected to transfer molding (molding time 4 minutes) at a molding temperature of 150 ° C. by using each test mold, and after-cured at 150 ° C. for 3 hours. Table 1 also shows the characteristic results of the various molded products obtained.

Using the epoxy resin compositions obtained in the above Examples and Comparative Examples, the evaluation ICs were transfer-molded and after-cured to obtain semiconductor devices. The progress of disconnection failure during PCT and heat cycle tests of this semiconductor device
Shown in Figures and FIG. Further, FIG. 3 shows the light transmittance of each epoxy resin composition at 400 to 600 nm.

[0019]

As is clear from the results of Table 1 and FIGS. 1 to 3, according to the present invention, an epoxy for encapsulating an optical semiconductor, which is excellent in heat resistance and moisture resistance, and has remarkably improved light transmittance. It is possible to obtain a resin composition, and thereby the moisture resistance reliability,
It is possible to provide an optical semiconductor device having excellent thermal shock resistance reliability and significantly improved light transmittance.

[Brief description of drawings]

FIG. 1 is a diagram showing a PCT leaving time and a failure occurrence rate.

FIG. 2 is a diagram showing the number of heat cycles and the defect occurrence rate.

FIG. 3 is a diagram showing the light transmittance of an epoxy resin composition at 400 to 600 nm.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location H01L 23/29 23/31 (72) Inventor Kohei Yasawa 1772-1 Kagoku, Yuki-shi, Ibaraki Hitachi Chemical Kogyo Minami Yuki Factory

Claims (1)

[Claims] 1. A resin composition comprising (A) an epoxy resin, (B) a bisphenol novolac resin, (C) a curing accelerator, and at least one of the following components (D) to (F). An epoxy resin composition for encapsulating an optical semiconductor element. (D) Organophosphorus compound (E) Thioether compound (F) Hindered phenol compound