RU2505567C1 - Press material for sealing integrated microcircuits - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: press material for sealing integrated microcircuits contains binder - o-cresol novolac epoxy resin with softening point of 50-65°C, a curing agent - cyan-acetic ester and diglycidyl ether of 1,4-butanediol, an accelerating atent - N¹-(3,4-dichlorophenyl)-N,N-dimethylurea, filler - ground quartz, glycidyloxypropyltrimethoxy silane finishing agent, lubricant - oxidised polyethylene wax.

EFFECT: invention enables to obtain press material which is characterised by high spiral fluidity and improved processability and longer shelf life.

1 tbl, 3 ex

Description

The invention relates to the production of composite materials based on epoxy and epoxyphenol resins used in the electrical and electronic industry for sealing integrated circuits.

Known epoxyphenolic compositions for molding composite materials used in the sealing of electronic devices, including for sealing integrated circuits containing epoxy resins of various structures as a binder, phenolic resin as a hardener, inorganic fillers and target additives.

So, by Sumitomo Bakelite Co. Developed epoxy compositions for semiconductor seals with good resistance to moisture and soldering, containing:

a) 85-92% (to the total weight of the composition) of inorganic fillers and target additives (fused silica powder 88 g, carbon black 0.3 g, carnauba wax 0.5 g, triphenyl phosphite 0.2 g);

b) at least 8% of a mixture of two epoxy resins of different structures, 20-80% of each (one of which is o-cresol epoxy);

c) at least 20% of a phenolic hardener (based on the binder);

d) curing accelerator.

A sample of the material in the form of a piece has a spiral fluidity of 80 mm (Korean application KR 9700092 C08L 63/00, publ. 1997; C. A, t.123, ref. 259312b).

Fire-resistant molding materials for sealing electronic devices with good moisture and heat resistance (Japanese application JP 2000 226499, C08L 63/00, publ. 2000, S.A., t.133, ref. 151764t), proposed by Hitachi Chem. Co., Ltd., contain, per 100 g of o-cresol-wave epoxy, 53.0 g of novolak, 15.7 g of tricalcium salt of nitrilo-tris (methylene) phosphonic acid, and 530 g of SiO ₂ (UL 94 VO).

Known developed by Mitsubishi Petrochemical Co., Ltd. epoxy compositions for a composite material with a glass transition temperature of 183 ° C (according to the application of Japan JP 0234626, C08G 59/62, publ. 1990) used for sealing electronic devices, characterized by low shrinkage during crosslinking and high heat resistance, containing 1 eq of epoxy resin 0 5-2.0 equiv of polyphenols and 0.01-20 wt.h. N- (imidazolyl) alkylurea. In the example (S.A., t.113, ref. 133840x) the following composition is given, parts by weight:

o-cresolnobolac epoxy, in particular Epicote 180 80 phenolic novolak (Tamanol 752 with hydroxy equivalent 104) fifty BREN (brominated phenolic novolak) twenty glycidyloxypropyltrimethoxysilane 0.5 fused quartz 300 antimony trioxide 5 stearic acid 2 soot 1,5 N, N ¹ bis (2-methylimidazolyl-1-ethyl) urea (I) 1,5

The material is obtained by mixing the starting components in the melt, grinding and injection molding at 175 ° C.

Characteristics of the material obtained in accordance with the application of Japan JP 0234626:

glass transition temperature, ° C 183 bending strength, kg / mm ² 14.1 shrinkage when stitching,% 0.30 linear thermal coefficient extensions, ∗ 10 ⁶ deg ^-1 twenty specific volume resistance, Ohm cm 3.5 ∗ 10 ¹⁶ (20 ° C) 8.0 * 10 ¹³ (150 ° C)

Mitsubishi Denki K.K. and Shin-Etsu Chem. Co., Ltd. proposed composition (European application EP 955675, H01L 23/29, publ. 1999), the closest in composition to the claimed. The composition includes an epoxy resin (preferably epoxycresol-dabbing), a crosslinking agent (preferably a phenolic novolac resin) and an inorganic filler in an amount of at least 70% by weight. (preferably 70-92% wt.) In this case, at least one epoxy resin and / or one crosslinking agent (but better both) have a molecular weight distribution of Mw / Mn less than 1.6, the content of binuclear compounds less than 8% by weight ., and the content of seven or more nuclear compounds is more than 32% wt.

In the description, it is noted that practically all known types of epoxy and phenolic resins are used in the preparation of the claimed composition, but out of seven examples that differ in various combinations of epoxy and phenolic resins and the amount of filler (not counting comparative examples), only one composition contains o-cresol epoxy with a softening point of 72 ° C. and a Mw / Mn of 1.41 (resin A) in combination with a phenolic wave resin with a softening point of 98 ° C. and a Mw / Mn of 1.24 (resin D).

The composition of a specific composition based on resins A and D (example E7 described in the description of the invention), the following (parts by weight):

resin A 54.75 resin D 35.25 filler, 300

Including:

- fused silica with an average particle size of 10 microns 20% wt. - spherical. fused silica with an average particle size of 30 microns 75% wt. - spherical. fused silica with an average particle size of 0.5 microns 5% of the mass. antimony trioxide 10.0 wax Wax E 1,5 soot 1,0 brominated epoxyphenol novolak with a bromine content of 35.5% 10.0 glycidyloxypropyltrimethoxysilane 1,0 triphenylphosphine 0.8

Note: 1) the sum of resins A, D and brominated novolak is 100 parts by weight; 2) the molar ratio of phenolic hydroxyl groups in the phenolic resin to epoxy groups in the epoxy resin is 1.0.

The percent filling of the compositions of the examples in accordance with the invention is 67.1-85.7.

When filled with 75.1% (Example E7), the spiral fluidity is 141 cm, and the hardness at elevated temperatures is 78 (on the Barkola scale). Spiral fluidity was measured according to the EMMI standard when forming a composition in a mold at 180 ° C. and a load of 70 kgf / cm ² .

Known press material, the closest in technical essence to the proposed one, which contains (% wt.): 25.0-27.0 binder - ortho-cresolnobolnova epoxy with a softening temperature of 50-65 ° C, 12.5-13, 5 hardeners - phenolic novolac resin brand SF-015, 0.06-0.08 accelerator-N, N ¹ -dimethyl-3-chlorophenylurea, 54.72-63.28 filler, including 32.0-35.0 ground quartz , 0.62-0.68 soot and 22.1-27.6 hexagonal boron nitride, 0.29-0.70 sizing glycidyloxypropyltrimethoxysilane, 0.46-0.59 flame retardant triphenylphosphine and 0.36-0.40 lubricants - polyethylene oxidized wax st. The binder was obtained by polycondensation of ortho-cresol with para-formaldehyde in an equimolar ratio in butanol medium, first in the presence of oxalic acid until 35-45% conversion was achieved, then in the presence of para-toluenesulfonic acid (PTSK) until the calculated amount of water was completely isolated (completion of the reaction) and then the interaction of the obtained intermediate with epichlorohydrin (ECG) in an alkaline medium (Russian patent RU 2447093, C08G 8/12, C08G 59/08, C08L 63/00, H01L 23/29, publ. 2012 - prototype).

However, the material according to the prototype is intended to solve a specific problem - ensuring the operability of the material in high vacuum at a temperature of 100-110 ° C with increased dissipation of heat generated (due to high thermal conductivity), eliminating overheating of the product during operation.

The technical task of the invention is to obtain on the basis of domestic raw materials cheaper press material used for the manufacture of a wide range of electronic and electrical products using integrated circuits.

The technical result, which consists in the development of a more highly filled press material, characterized by increased fluidity in a spiral and improved manufacturability and shelf life, is achieved by the fact that the press material for sealing integrated circuits, including a binder - ortho-cresolobolac epoxy resin with a softening temperature of 50-65 ° C - product the polycondensation of ortho-cresol with para-formaldehyde in an equimolar ratio, first in the presence of oxalic acid until 35-45% conversion is achieved, then in the presence of PTS To the completion of the reaction and subsequent interaction of the obtained product with epichlorohydrin in an alkaline medium, a hardener, an accelerator is a phenylurea derivative, a filler is ground quartz, a sizing agent is glycidyloxypropyltrimethoxysilane and a lubricant is oxidized polyethylene wax; it contains cyanacetic acid and diglycidyl ether as a hardener -butanediol, as the accelerator N ¹ - (3,4-dichlorophenyl) -N, N-dimethylurea in the following ratio, wt.%:

softening o-cresolwax epoxy resin 50-65 ° C 16.24-21.93 cyanoacetic acid ester of diglycidyl ether 1,4-butanediol 4.87-6.58 N ¹ - (3,4-dichlorophenyl) -N, N-dimethylurea 0.49-0.66 ground quartz 70.19-77.93 glycidyloxypropyltrimethoxysilane 0.06-0.09 oxidized polyethylene wax 0.41-0.55

The invention is illustrated by the following example:

Example 1

Obtaining a binder (in accordance with example 1 of RU 2447093): polycondensation of ortho-cresol (108 parts by weight) and para-formaldehyde (28.5 parts by weight) is carried out at 115 ± 2 ° C in n-butanol (250 parts by weight) initially in the presence of 6 parts by weight oxalic acid to achieve 35% conversion, after which add 3 wt.h. PTSK, continuing to heat until the allocation of 12 wt.h. condensation water (82% of the theoretical amount of condensation water). After distillation of 150 ml of butanol, the reaction mass is neutralized with an aqueous solution of sodium hydroxide, then 350 parts by weight are added. ECG (3.7 mol). The mixture is cooled to 60 ° C and added 3 times in portions over 1.5 hours (at 30 minute intervals) of 15 parts by weight. chopped caustic soda while maintaining a temperature of 65-70 ° C. The mixture was cooled, 450 ml of chloroform was added and filtered. The chloroform solution is washed with warm distilled water, the lower chloroform layer is separated, and chloroform is first distilled off at 50-70 ° C and 10 mm Hg. with a gradual increase in temperature by 1.5-2 degrees / min to 120 ° C at 20 mm Hg with exposure under these conditions for an hour. Get a resin with a softening temperature of 50 ° C.

Obtaining composite material: to 390 parts by weight (74.16 wt.%) Industrially produced powdered silica quartz (KMP grade B) add 0.4 wt.h. (0.08 wt.%) Glycidyloxypropyltrimethoxylan in the form of a solution in chloroform, the mixture is stirred and chloroform is removed at 50-100 mm Hg and a temperature of 60-70 ° C. In 100 parts by weight (19.02 wt.%) Ortho-cresolnovolac epoxy resin obtained by the above method, preheated to a temperature of 105-110 ° C, 30 wt.h. (5.7 wt.%) Hardener - ester of cyanoacetic acid and diglycidyl ether of 1,4-butanediol. The composition is stirred until complete homogenization and drained for further cooling and grinding.

390.4 parts by weight are placed in a ball mill with ceramic balls. (74.15 wt.%)) Finished quartz, 130 wt. (24.72 wt.%) Pre-crushed ortho-cresol epoxy binder, 3 wt.h. (0.57 wt.%) N ¹ - (3,4-dichlorodiphenyl) -N, N ^- dimethylurea, 2.5 wt.h. (0.48 wt.%) Polyethylene wax. Mixing is carried out until the resulting powder passes completely through a 0.5 mm sieve. Then the powder is homogenized on rollers with electric heating and a roll temperature of 90-95 ° C. The material obtained after rolling in the form of scales is crushed and sieved through a 0.5 mm vibrating screen. The curing cycle by pressing is 180 seconds at 175 ° C, after which curing is carried out for 1 hour at the same temperature.

Examples 2-3. The preparation of the material is carried out according to the procedure described in example 1, using the appropriate quantities of the starting components

The compositions of the examples and characteristics of the materials obtained are presented in the table.

Table The compositions and characteristics of the materials in the examples. Name of components The number of components, wt.% example 1 example 2 example 3 prototype example 1 epoxy resin 19.02 16.24 21.93 26.0 phenolic novolac resin SF-015 - - - 13.0 cyanoacetic acid ester of diglycidyl ether 1,4-butanediol 5.7 4.87 6.58 - N ¹ - (3,4-dichlorophenyl) -N, N-dimethylurea 0.57 0.49 0.66 - N, N ¹ -dimethyl-3-chlorophenylurea - - - 0.06 ground quartz 74.15 77.93 70.19 32,0 glycidyloxypropyltrimethoxysilane 0.08 0.06 0.09 0.60 oxidized polyethylene wax 0.48 0.41 0.55 0.36 hexagonal boron nitride - - - 26.9 technical carbon (soot) - - - 0.62 triphenylphosphine - - 0.46 Characteristics of materials: glass transition temperature, ° C 145 150 145 169 spiral flow, cm 95 90 BY 55 bending strength, MPa one hundred one hundred 105 90 coefficient of linear thermal expansion, ∗ 10 ⁶ deg ^-1 twenty 23 23 23 thermal conductivity, W / m ^∗ deg 0.7 0.8 0.7 1,5 storage period, months 7 7 7 four Charpy impact strength without notch, kJ / m ² 1,5 1.3 2.0 1,5

The developed press material, which includes a specially prepared hardener in combination with a well-known accelerator (Diuron trademark), provides the possibility of its use for sealing a wide range of microelectronic products with thermal conductivity of 0.7-0.8 W / m ^* deg, made using integrated circuits, especially small-sized ones, including mobile ones, which is of particular interest for miniaturization of products.

The proposed hardener obtained using known methods for the synthesis of cyanoacetic acid esters and derivatives of diols - but as a chemical compound not described in the literature - is a liquid product with a viscosity of 20-25 Pa · s, which is both a hardener and a diluent. Its use provides:

- the possibility of obtaining more highly filled composites (filler content of about 80% (77.93% versus 63.28% of the prototype), which reduces the cost of the material; while almost 10% increase in strength properties without slight deterioration in some compositions (in particular, only in one of three examples) of shock characteristics.

An important advantage of the proposed material is also almost doubled shelf life (7 months versus 4 months for the prototype).

Claims (1)

A press material for sealing integrated circuits, including a binder - ortho-cresol-wave epoxy resin with a softening temperature of 50-65 ° C - the product of polycondensation of ortho-cresol with para-formaldehyde in an equimolar ratio, first in the presence of oxalic acid, to achieve 35-45% conversion, then in the presence of para-toluenesulfonic acid until the reaction is completed and the resulting product interacts with epichlorohydrin in an alkaline medium, hardener, accelerator - phenylurea derivative, filler - quartz mo cast, coupling agent - glycidyloxypropyltrimethoxysilane and lubricant - oxidized polyethylene wax, characterized in that the material contains cyanoacetic acid ester and diglycidyl ether 1,4-butanediol as an hardener and N ¹ - (3,4-dichlorophenyl) -N as an accelerator, N-dimethylurea in the following ratio, wt.%:
o-cresol bracer epoxy with a softening temperature of 50-65 ° C 16.24-21.93 ester of cyanoacetic acid and diglycidyl 1,4-butanediol ether 4.87-6.58 N ¹ - (3,4-dichlorophenyl) -N, N-dimethylurea 0.49-0.66 ground quartz 70.19-77.93 glycidyloxypropyltrimethoxysilane 0.06-0.09 oxidized polyethylene wax 0.41-0.55