TW201738350A - A kind of flow type chip level underfill and its preparation method - Google Patents

Abstract

The invention belongs to the underfill preparation technology field, it especially relates to a kind of flow type chip level underfill and its preparation method. The chip level underfill do not use any kind of diluents. The underfill including the characteristics of flow speed, high reliability, low thermal expansion coefficient, high bending modulus, low moisture absorption, etc. The addition of dispersant can reduce viscosity, increase the flow rate, uniform filler dispersion, ensure the reliability of the packaging components.

Description

Flow type wafer level underfill glue and preparation method thereof

This creation is about a structural improvement of a locomotive air filter; more specifically, the present invention relates to an improved locomotive air filter structure for an improved intake manifold structure.

With the rapid development of the electronic packaging industry, more stringent requirements have been placed on electronic packaging materials. Since the thermal expansion coefficient of wafers made of tantalum material is much lower than that of substrates, underfill is widely used in electronic packaging materials in order to protect wafers, solder balls and solder joints and enhance wafer reliability. The underfill is usually made of epoxy resin, which has excellent properties such as high toughness, corrosion resistance, high viscosity and good insulation. However, most of the underfills currently have shortcomings such as high brittleness, low reliability, large internal stress, poor heat resistance, and poor moisture resistance, which can only meet the requirements of secondary packaging.

The present invention is directed to the deficiencies of the prior art described above, and provides a flow type wafer level underfill and a preparation method thereof.

The technical solution of the present invention to solve the above technical problems is as follows: a flow type wafer level underfill, the composition of which is composed of the following parts by weight: epoxy resin 18 parts to 30 parts, toughening agent 1 part to 3 parts, wettability dispersion The solvent is 0.1 part by weight to 1 part, the coupling agent is 0.1 part to 1 part, the carbon black is 0.1 part to 0.5 part, the filler is 50 parts to 70 parts, and the curing agent is 8 parts to 15 parts.

Further, the epoxy resin is a mixture of two or more of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a polycyclic aromatic epoxy resin, and a novolac type epoxy resin.

Further, the bisphenol A type epoxy resin is E51, E44 or EPON 825; the bisphenol F type epoxy resin is EPIKOTE 862 or EPIKOTE 983U; and the polycyclic aromatic epoxy resin is EPICLON HP4700, EPICLONHP4500 or EPICLONHP4032; the phenolic epoxy resin is DEN 431, DEN 438 or DEN 439.

The beneficial effect of adopting the above further solution is that selecting different types of epoxy resin combinations can more effectively exert the advantages of various epoxy resins, so that thermal stability, thermal expansion coefficient and the like reach an equilibrium point, thereby obtaining excellent comprehensive performance.

Further, the toughening agent is a liquid end carboxylated nitrile rubber, a methyl vinyl niobium rubber, a dimethyl vinyl niobium rubber, a methylphenyl vinyl niobium rubber or a methyl diphenyl vinyl niobium rubber.

The beneficial effect of the above further solution is that the addition of the toughening agent can adjust the toughness of the cured product, effectively increase the elastic modulus, lower the thermal expansion coefficient, and meet the impact resistance requirements.

Further, the wetting and dispersing agent is a fatty alcohol polyoxyethylene ether, a fatty amine polyoxyethylene ether or an alkylphenol ethoxylate.

The beneficial effect of using the above further solution is that the addition of the wetting and dispersing agent effectively reduces the viscosity of the system and increases the flow wettability of the system.

Further, the coupling agent is β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, γ-glycidoxypropyltrimethoxydecane or γ-mercaptopropyltrimethoxydecane. One or a mixture of two or more.

Further, the carbon black is a high pigment carbon black.

Further, the filler is a spherical niobium fine powder having a particle diameter of less than 15 μm and an average particle diameter of 1.5 μm to 7.5 μm.

The beneficial effect of adopting the above further solution is that the maximum particle size of the bismuth micropowder is 15 μm and the average particle diameter is between 1.5 μm and 7.5 μm, so that the small gap wafer can be quickly and well filled, and the spherical bismuth micropowder is selected to make the fluidity of the resin and the filler. Achieve consistency.

Further, the curing agent is a modified amine compound or an acid anhydride compound.

Further, the modified amine compound is a modified aromatic amine, a modified polyamine or a modified dicyandiamide; the acid anhydride compound is tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride or Methyl hexahydrophthalic anhydride.

A second object of the present invention is to provide a method for preparing a flow type wafer level underfill, which is as follows:

(1) Weigh 18 to 30 parts of epoxy resin and 0.1 to 0.5 parts of carbon black, stir into the reaction vessel for 0.5 to 1 hour, mix well, grind and put into the reaction kettle;

(2) Weighing 1 to 3 parts of toughening agent, 0.1 part to 1 part of wetting and dispersing agent, and 0.1 part to 1 part of coupling agent, and putting it into a reaction kettle and stirring for 1 to 2 hours, and mixing uniformly;

(3) Weigh 50 to 70 parts of the filler, put it into the reaction kettle and stir for 2 to 4 hours, mix well, after grinding, put it into the reaction kettle, the temperature is controlled at 40 ~ 80 ° C, and let stand for 3 ~ 8h;

(4) The temperature is controlled at 20 to 25 ° C, and 8 to 15 parts of the curing agent is weighed, and it is put into a reaction kettle and stirred under vacuum for 1 to 2 hours, and uniformly mixed to obtain a filling gel.

Further, the stirring speed in the steps (1) to (3) was 1000 rpm; and the stirring speed in the step (4) was 300 rpm.

The advantageous effect of using the above further embodiment is that in step (4), the stirring speed is lowered after the addition of the curing agent, and the heat generated by the stirring can be reduced.

Further, the filler in the step (3) is uniformly mixed with other raw materials in the reaction vessel, and then ground in a three-roll mill, and then added to the reaction vessel, and allowed to stand at 40 to 80 °C.

The beneficial effect of using the above further solution is that the high temperature conditions facilitate the sufficient wetting and dispersion of the resin and the filler.

Further, the vacuum degree of vacuuming in step (4) is less than -0.095 MPa, and nitrogen gas protection is required when the reactor is decompressed.

The invention has the beneficial effects that the wafer-level underfill made by the invention does not use any kind of diluent and has the characteristics of fast flow speed, high reliability, low thermal expansion coefficient, high flexural modulus and low hygroscopicity. The addition of the wetting and dispersing agent effectively reduces the viscosity, and the effect of increasing the flow speed is remarkable, and the filler is more evenly dispersed, thereby ensuring the reliability of the packaged components.

no

Flow performance test, a device consisting of a gap sheet and a cover slip, a slide glass having a gap of 50 μm (simulating package component gap), and measuring the time required for the product to flow 10 mm at 100 ° C, in units of s.

Water absorption test, using saturated steam test (PCT), temperature 121 ° C, humidity 100% R.H., time 20 h.

Curing performance test, using differential scanning calorimetry (DSC), the curing time required to completely cure the product at a constant temperature of 150 ° C, in min.

The coefficient of thermal expansion test (CTE) is tested in accordance with the American ASTM D696 standard using thermomechanical analysis (TMA) in μm/m °C.

The modulus of elasticity test was tested according to the American ASTM E1142 standard using a dynamic mechanical analyzer (DMA) in units of GPa.

Shear strength test, curing conditions are cured at 150 ° C for 90 min, according to the Chinese GB / T7124-1986 test method, measuring AL / AL shear strength, unit MPa.

Example 1

A method for preparing a flow type wafer level underfill is as follows:

(1) Weigh 80g of bisphenol A epoxy resin E51, 100g of phenolic epoxy resin DEN 431 and 5g of carbon black, put it into the reaction vessel and stir it at 1000rpm for 0.5~1h, mix well, grind it and put it into the reaction kettle. in;

(2) weighing 20 g of liquid terminal carboxylated nitrile rubber, 10 g of fatty alcohol polyoxyethylene ether and 5 g of γ-mercaptopropyltrimethoxydecane, and putting them into a reaction vessel and stirring at 1000 rpm for 1 to 2 hours, and mixing uniformly;

(3) Weigh 700g of bismuth fine powder with an average particle size of 7.5μm, put it into the reaction vessel and stir it at 1000rpm for 2~4 hours, mix well, grind it and put it into the reaction kettle. The temperature is controlled at 40~80°C. , standing for 3 ~ 8h;

(4) The temperature is controlled at 20 to 25 ° C, and 80 g of methyltetracyanophthalic anhydride is weighed, and the mixture is placed in a reaction vessel and evacuated, and stirred at 300 rpm for 1 to 2 hours, and uniformly mixed to obtain a filling gel.

Example 2

A method for preparing a flow type wafer level underfill is as follows:

(1) Weigh bisphenol F type epoxy resin EPIKOTE 983U 120g, polycyclic aromatic epoxy resin EPICLON HP4700 100g and carbon black 5g, put into the reaction kettle and stir at 1000 rpm for 0.5~1h, mix well, after grinding Put into the reaction kettle;

(2) Weigh 30 g of methyl phenylethylene oxime rubber, 10 g of fatty amine polyoxyethylene ether and 5 g of β-(3,4-epoxycyclohexyl)ethyltrimethoxy decane, and put them into a reaction kettle for stirring 1 ~2h, evenly mixed;

(3) Weigh 630g of niobium micropowder with an average particle diameter of 1.5μm, put it into the reaction vessel and stir it at 1000rpm for 2~4 hours, mix well, and then put it into the reaction kettle after grinding. The temperature is controlled at 40~80°C. , standing for 3 ~ 8h;

(4) The temperature is controlled at 20 to 25 ° C, 100 g of modified aromatic amine is weighed, put into a reaction kettle, vacuumed, stirred at 300 rpm for 1 to 2 h, and uniformly mixed to obtain a filling gel.

Example 3

A method for preparing a flow type wafer level underfill is as follows:

(1) Weigh 160 mg of bisphenol A type epoxy resin E44, 100 g of polycyclic aromatic epoxy resin EPICLON HP4500 and 5 g of carbon black, and put it into the reaction vessel and stir at 1000 rpm for 0.5 to 1 h, mix well, grind and put in In the reaction kettle;

(2) Weigh 20 g of dimethylphenylvinylguanidine rubber, 5 g of fatty amine polyoxyethylene ether and 10 g of β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, and put them into a reaction kettle. Stir at 1000 rpm for 1 to 2 hours, and mix well;

(3) Weigh 560g of bismuth fine powder with an average particle diameter of 5μm, put it into the reaction vessel and stir it at 1000rpm for 2-4 hours, mix well, and then put it into the reaction kettle after grinding, the temperature is controlled at 40-80 °C. Let stand for 3~8h;

(4) The temperature is controlled at 20 to 25 ° C, 140 g of modified dicyandiamide is weighed, put into a reaction kettle, vacuumed, stirred at 300 rpm for 1 to 2 h, and uniformly mixed to obtain a filling gel.

Example 4

A method for preparing a flow type wafer level underfill is as follows:

(1) Weigh 150g of bisphenol F-type epoxy resin EPIKOTE 862 epoxy resin, 150g of phenolic epoxy resin DEN 439 and 5g of carbon black, and put it into the reaction vessel and stir it at 1000rpm for 0.5~1h, mix well, grind it. After being put into the reaction kettle;

(2) Weighed 30 g of methyl phenylethylene oxime rubber, 5 g of alkylphenol ethoxylate, and 10 g of γ-glycidoxypropyltrimethoxy decane, and put them into a reaction vessel and stirred at 1000 rpm for 1 ～. 2h, evenly mixed;

(3) Weigh 500g of bismuth fine powder with an average particle diameter of 3μm, put it into the reaction vessel and stir it at 1000rpm for 2-4 hours, mix well, and then put it into the reaction kettle after grinding, the temperature is controlled at 40-80 °C. Let stand for 3~8h;

(4) Temperature control at 20 ~ 25 ° C, weigh 150g of hexahydrophthalic anhydride, put it into the reaction kettle, vacuum, stir at 300rpm for 1-2h, mix evenly, that is, fill the glue

Comparative example 1

A method for preparing a wafer level underfill, the steps are as follows:

(1) Weigh bisphenol F type epoxy resin EPIKOTE 983U 120g, polycyclic aromatic epoxy resin EPICLON HP4700 100g and carbon black 5g, put into the reaction kettle and stir at 1000 rpm for 0.5~1h, mix well, after grinding Put into the reaction kettle;

(2) Weigh 30 g of methyl phenylethylene ruthenium rubber and 5 g of β-(3,4-epoxycyclohexyl)ethyltrimethoxy decane, and put them into a reaction kettle and stir at 1000 rpm for 1 to 2 h, and mix. Uniform

(3) Weigh 630g of fine powder of 1.5μm average particle size, put it into the reaction vessel and stir it at 1000rpm for 2~4 hours, mix well, grind it and put it into the reaction kettle, the temperature is controlled at 40~80 °C, Let stand for 3~8h;

(4) The temperature is controlled at 20 to 25 ° C, 150 g of hexahydrophthalic anhydride is weighed, put into a reaction kettle, vacuumed, stirred at 300 rpm for 1 to 2 h, and uniformly mixed to obtain a filling gel.

Comparative example 2

A method for preparing a wafer level underfill, the steps are as follows:

(1) Weigh 400 g of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate and bis(7-oxabicyclo[4.1.0]3-heptylmethyl) 400 g of diester and 5 g of hexafluoroantimonate were placed in a reaction vessel and stirred at 1000 rpm for 0.5 to 1 h, mixed uniformly, and then ground into a reaction vessel;

(2) Control the temperature at 15 ° C ~ 20 ° C, weigh 100 g of acrylic epoxy resin, 50 g of butyl acrylate, 30 g of 1,4-butanediol, β-(3,4-epoxycyclohexyl)ethyltrimethoxy 10 g of decane, 3 g of benzammonium peroxide and 2 g of carbon black were placed in a reaction vessel and evacuated, and stirred at 500 rpm for 2 to 4 hours, and uniformly mixed to obtain a filling gel.

The fillers prepared in the above Examples 1-4 and the fillers prepared in Comparative Examples 1-2 were tested for performance indexes, and the results are shown in Table 1.

Table 1 performance indicators comparison

[0075] As can be seen from the data in Table 1, the wafer-level underfill produced by the present invention has a curing time longer than that of the secondary underfill, and is faster in flow time than the secondary underfill, so that the glue is filled. And less internal defects are formed during the curing process; the thermal expansion coefficient, water absorption, flexural modulus, shear strength, etc. have obvious advantages over the secondary package underfill. This determines that the wafer-level underfill produced by the present invention has higher reliability and meets the requirements of a first-level high-density wafer-level package. In addition, the addition of the wetting and dispersing agent in the present invention has a significant effect of effectively lowering the viscosity and increasing the flow rate. Since the wafer level underfill does not use any diluent, it has higher reliability.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are within the spirit and scope of the present invention, should be included in the protection of the present invention. Within the scope.

Claims (9)

A flow type wafer level underfill, characterized in that the composition thereof is composed of the following parts by weight: 18 parts to 30 parts of epoxy resin, 1 part to 3 parts of toughening agent, 0.1 part to 1 part of wetting and dispersing agent, The coupling agent is 0.1 part by weight to 1 part, the carbon black is 0.1 part to 0.5 part, the filler is 50 parts to 70 parts, and the curing agent is 8 parts to 15 parts. The flow type wafer level underfill according to claim 1, wherein the epoxy resin is bisphenol A epoxy resin, bisphenol F epoxy resin, polycyclic aromatic epoxy resin, and phenolic type. Two or more kinds of epoxy resins are mixed. E44 or EPON 825; the bisphenol F type epoxy resin is EPIKOTE 862 or EPIKOTE 983U; the polycyclic aromatic epoxy resin is EPICLON HP4700, EPICLONHP4500 or EPICLONHP4032; the phenolic epoxy resin is DEN 431, DEN 438 or DEN 439. The flow type wafer level underfill according to claim 1, wherein the toughening agent is liquid end carboxylated nitrile rubber, methyl vinyl niobium rubber, dimethyl vinyl niobium rubber, methyl phenyl ethylene矽Rubber or methyl diphenylethylene ruthenium rubber;
Wherein the wetting and dispersing agent is a fatty alcohol polyoxyethylene ether, a fatty amine polyoxyethylene ether or an alkylphenol ethoxylate;
Wherein the coupling agent is one of β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, γ-glycidoxypropyltrimethoxydecane or γ-mercaptopropyltrimethoxydecane or Mixing two or more;
The carbon black is a high pigment carbon black;
The filler is a spherical niobium fine powder having a particle diameter of less than 15 μm and an average particle diameter of 1.5 μm to 7.5 μm. The flow type wafer level underfill according to claim 1, wherein the curing agent is a modified amine compound or an acid anhydride compound. The flowable wafer level underfill according to claim 5, wherein the modified amine compound is a modified aromatic amine, a modified polyamine or a modified dicyandiamide; Tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride or methylhexahydrophthalic anhydride. A method for preparing a flow type wafer level underfill, characterized in that the steps are as follows:
(1) Weigh 18 to 30 parts of epoxy resin and 0.1 to 0.5 parts of carbon black, stir into the reaction vessel for 0.5 to 1 hour, mix well, grind and put into the reaction kettle;
(2) Weighing 1 to 3 parts of toughening agent, 0.1 part to 1 part of wetting and dispersing agent, and 0.1 part to 1 part of coupling agent, and putting it into a reaction kettle and stirring for 1 to 2 hours, and mixing uniformly;
(3) Weigh 50 to 70 parts of the filler, put it into the reaction kettle and stir for 2 to 4 hours, mix well, after grinding, put it into the reaction kettle, the temperature is controlled at 40 ~ 80 ° C, and let stand for 3 ~ 8h;
(4) The temperature is controlled at 20 to 25 ° C, and 8 to 15 parts of the curing agent is weighed, and it is put into a reaction kettle and stirred under vacuum for 1 to 2 hours, and uniformly mixed to obtain a filling gel. The method for preparing a flow type wafer level underfill according to claim 7, wherein the stirring speed in the steps (1) to (3) is 1000 rpm; and the stirring speed in the step (4) is 300 rpm. The method for preparing a flow type wafer-level underfill according to claim 7, wherein the vacuum degree of the vacuum in the step (4) is less than -0.095 MPa, and the reactor is subjected to nitrogen gas protection when the pressure is released.