CN117777918A - Reworkable toughening chip-level underfill adhesive and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of adhesives, in particular to a reworkable and toughened chip-level underfill adhesive and a preparation method thereof. The invention provides an underfill adhesive, which comprises the following components in parts by weight: 15-25 parts of bisphenol F type epoxy resin, 3-8 parts of tetraglycidyl ether containing furan groups which is synthesized autonomously, 0.5-2 parts of bismaleimide resin, 0.5-1.5 parts of silane coupling agent, 0.5-1.5 parts of leveling agent, 0.5-1.5 parts of black paste, 60-70 parts of spherical silicon micro powder and 5-15 parts of curing agent. According to the invention, the tetraglycidyl ether containing furan groups is innovatively introduced, and meanwhile, the bismaleimide resin is matched, so that a cured product formed by a final formula product has higher heat-resistant temperature, excellent flexibility and reworkable performance.

Description

Reworkable toughening chip-level underfill adhesive and preparation method thereof

Technical Field

The invention relates to the technical field of adhesives, in particular to a reworkable and toughened chip-level underfill adhesive and a preparation method thereof.

Background

In the chip packaging technology, the bonding layer of the IC chip and the organic substrate consists of a large number of micro-sized welding spots, so that the deformation adaptability of the bonding layer is poor, the bonding layer is extremely sensitive to thermal stress, and the problem of structural reliability is more remarkable. The use of polymer underfilling to improve the reliability of packaged chips is a method commonly used today throughout the year. The method is economical and easy, and during the chip packaging process, underfill material (underwill) is gradually solidified and formed in the slit between the IC chip and the organic substrate by thermal curing, and the solder joints of the connection are protected. Meanwhile, the impact load can be effectively slowed down, the performances of deformation resistance, moisture resistance, chemical corrosion resistance and the like of the packaged chip are improved, and the fatigue life of the packaged chip can be greatly prolonged, so that the packaging chip has great development potential.

The chip-scale underfill contacts three parts: upper chip, middle Bump, and lower carrier. The Bump material is usually metallic tin or an alloy of tin and other metals, and has a low melting temperature, and can be easily melted and deformed to be separated from the underfill material at a repairing temperature. But the surfaces of the upper chip and the lower carrier plate are in large-area contact with the underfill material, so that the adhesive force is high. The repairing temperature is usually 260-300 ℃, and the bonding force between the underfill material and the interface is relatively high when the temperature is too low, so that the chip and the carrier plate are easily damaged during repairing; the chip and the carrier plate may be damaged by the too high temperature. The conventional chip-scale underfill materials, due to their formulation characteristics, are difficult to achieve with reworkable without damaging the chip and carrier.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention provides a reworkable and toughened chip-level underfill and a preparation method thereof.

The technical scheme for solving the technical problems is as follows:

the invention provides a reworkable and toughened chip-level underfill adhesive, which comprises the following components in parts by weight:

15-25 parts of bisphenol F type epoxy resin, 3-8 parts of tetraglycidyl ether containing furan groups which is synthesized autonomously, 0.5-2 parts of bismaleimide resin, 0.5-1.5 parts of silane coupling agent, 0.5-1.5 parts of leveling agent, 0.5-1.5 parts of black paste, 60-70 parts of spherical silicon micro powder and 5-15 parts of curing agent.

The beneficial technical effects of adopting above-mentioned technical scheme lie in: when the chip-level underfill is cured, the imide groups in the bismaleimide resin are combined with the furan groups in the tetraglycidyl ether containing the furan groups to generate crosslinking points, and the formed structure has certain rigidity and can resist higher temperature; meanwhile, when the temperature reaches 280-300 ℃, the cross-linking point of the combination of the furan group and the imide group can be reversibly decomposed, so that the interface bonding effect is directly affected, the interface is favorably damaged and layered, and the reworkable effect is further achieved.

Based on the technical scheme, the invention can also make the following technical improvements:

further, the tetraglycidyl ether containing furan group is 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyldisiloxane) ] -tetraglycidyl ether.

The beneficial technical effects of adopting the further technical scheme are as follows: the structure contains four epoxy groups, has higher reactivity, can fully react with a curing agent to form more crosslinking points, improves the crosslinking density, and provides higher heat resistance for the cured underfill; meanwhile, the structure also contains a furan group and a benzene ring which are rigid groups, and heat resistance is provided for the cured underfill; in addition, the structure also contains 6 ether bonds and tetramethylsilane chain segments, so that flexibility is provided for the cured underfill, the flexibility can not only improve the reliability of cold and hot impact, high-temperature storage and the like in the reliability process of chip packaging, but also reduce the high-temperature modulus of the cured underfill to the greatest extent at the repairing temperature, and the crosslinking point combined with the furan group and the imide group can have a synergistic effect of reversible decomposition, so that the repairing difficulty is further reduced, and the repairing effect is achieved.

Further, the tetraglycidyl ether containing the furan group is prepared by the following method:

(1) Taking alpha-furaldehyde and 2-methoxy-4- (2-propenyl) phenol as the first step of reaction monomers, xylene as a solvent and methylimidazole as a catalyst, and performing condensation reaction to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol (the structural formula is shown as formula (I));

(2) Taking 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol and epichlorohydrin as a second step reaction monomer, taking tetrabutylammonium bromide as a phase transfer catalyst, performing ring opening reaction to obtain an intermediate 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] propyl chlorohydrin ether (structural formula is shown as formula (II)), adding sodium hydroxide, and performing closed-loop reaction to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether (structural formula is shown as formula (III));

(3) Taking 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether and tetramethyl dihydro disiloxane as a third step reaction monomer, adding a platinum catalyst, and performing a first addition reaction to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl-dihydro disiloxane) ] glycidyl ether (structural formula is shown as formula (IV));

(4) The method comprises the steps of taking 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl-hydrogen disiloxane) ] glycidyl ether and propenyl glycidyl ether as fourth-step reaction monomers, adding a platinum catalyst, and performing second addition reaction to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl disiloxane) ] -tetraglycidyl ether (the tetraglycidyl ether containing furan groups for short, the TGEF for short, and the structural formula is shown as formula (V)).

Further, in the step (1), the molar ratio of the alpha-furaldehyde to the 2-methoxy-4- (2-propenyl) phenol is 1:1-1:5, the mass ratio of the methylimidazole to the first-step reaction monomer is 0.1-10:100, and the mass ratio of the dimethylbenzene to the first-step reaction monomer is 40-80:100. To ensure that the reaction is sufficiently complete.

Further, in the step (2), the molar ratio of the 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol to the epichlorohydrin is 1:2-20, the molar ratio of the 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] propyl chlorohydrin ether to the sodium hydroxide is 1:2-10, and the mass ratio of the tetrabutylammonium bromide to the second-step reaction monomer is 0.1-2:100. To ensure that the reaction is sufficiently complete.

Further, in the step (3), the molar ratio of the 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether to the tetramethyl dihydro disiloxane is 1:2-10. Ensure that the reaction is fully complete.

Further, in the step (4), the molar ratio of the 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl-monohydrodisiloxy) ] glycidyl ether to the propenyl glycidyl ether is 1:2-10. To ensure that the reaction is sufficiently complete.

Further, the condensation reaction temperature in the step (1) is 50-120 ℃, and the condensation reaction time is 1-20 hours; the ring-opening reaction temperature in the step (2) is 20-120 ℃, the ring-opening reaction time is 1-10 hours, the ring-closing reaction temperature is 20-50 ℃, and the ring-closing reaction time is 1-10 hours; the first addition reaction temperature in the step (3) is 50-100 ℃, and the first addition reaction time is 1-10 hours; the second addition reaction temperature in the step (4) is 50-100 ℃, and the second addition reaction time is 1-10 hours.

Further, the bismaleimide resin is an oligomeric bismaleimide resin (BMI) with a molecular weight of 500-5000 (structural formula is shown as formula (VI), n=1-100, n is 10 in the examples and comparative examples of the invention), the bisphenol F epoxy resin is EXA-830CRP of Japan DIC company, the silane coupling agent is KBM-403 (3-glycidoxypropyl trimethoxysilane) of Japan Xinyu company, the leveling agent is AC1203 (fatty amine polyoxyethylene ether) of Jiangsu sea-ampere, the black paste is JSLD6909 (carbon black added to bisphenol A epoxy resin) of a new material, the spherical silicon micropowder is SE6050-SEJ of Japan Yakuma company, and the curing agent is E-100 (diethyl toluene diamine) of Jiangsu Nitro chemical industry.

The technical effect of adopting the further technical scheme is as follows: the maleic amide bond in the bismaleimide and the furan group in the tetraglycidyl ether are combined to generate a crosslinking point, when the temperature reaches 280-300 ℃ or higher, the crosslinking point combined by the furan group and the imide group can be reversibly decomposed (as shown in a reaction formula 1), the interface bonding effect is directly affected, the interface is favorably damaged and layered, and the reworkable effect is further achieved.

Reaction formula 1:

the second aspect of the present invention provides a method for preparing the reworkable chip-level underfill, comprising the steps of:

s1, carrying out melt dispersion on bisphenol F type epoxy resin and bismaleimide resin under a vacuum condition of 100-200 ℃ to obtain premixed resin;

s2, mixing bisphenol F epoxy resin, premix resin, tetraglycidyl ether containing furan groups, a silane coupling agent and black paste, stirring for 1h, adding spherical silicon micropowder, heating and stirring for 2-10h at 70-90 ℃ in vacuum, and grinding by three rollers after cooling to normal temperature to form an underfill premix;

and S3, blending the underfill premix, the leveling agent and the curing agent, and stirring for 1-2 hours at the temperature of 25-30 ℃ to obtain the chip-level underfill.

The beneficial technical effects of adopting above-mentioned technical scheme lie in: the bismaleimide resin is solid powder, and is melted and blended with bisphenol F type epoxy resin in advance, so that the subsequent glue preparation operation is facilitated.

Compared with the prior art, the invention has the following technical effects:

the invention synthesizes tetraglycidyl ether containing furan group autonomously, the compound with the novel special structure and low molecular weight bismaleimide resin are introduced into the formula design, and a repairable and toughening chip-level underfill is developed successfully through reasonable component proportion design, so that the purpose of repairing is achieved in the repairing temperature range, and meanwhile, the tetraglycidyl ether has better toughness and higher heat-resistant temperature, and the reliability test performance of the packaged chip can be improved; the tetraglycidyl ether containing furan groups can provide higher heat resistance and excellent flexibility after solidification for chip-level underfill; the bismaleimide resin is combined with furan groups in the tetraglycidyl ether containing the furan groups at high temperature, so that the reworkable difficulty is reduced, and the reworkable effect is further achieved.

Detailed Description

Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present specification, by describing the embodiments of the present invention with specific examples. While the description of the invention will be described in connection with the preferred embodiments, it is not intended to limit the inventive features to the implementation. Rather, the purpose of the invention described in connection with the embodiments is to cover other alternatives or modifications, which may be extended by the claims based on the invention. The following description contains many specific details for the purpose of providing a thorough understanding of the present invention. The invention may be practiced without these specific details. Furthermore, some specific details are omitted from the description in order to avoid obscuring the invention. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.

Synthesis example

The synthesis process of the tetraglycidyl ether containing furan groups comprises the following steps:

(1) Adding 328g of 2-methoxy-4- (2-propenyl) phenol, 200g of dimethylbenzene and 6g of methylimidazole into a four-mouth flask equipped with a stirring device, a reflux condenser, a thermometer, a nitrogen pipe and a peristaltic pump feed pipe in sequence, introducing nitrogen, heating to 100 ℃, dropwise adding 48g of alpha-furaldehyde into the four-mouth flask within 0.5h through a peristaltic pump, reacting for 3h, cooling to normal temperature (25+/-3 ℃), adding acetic acid to neutralize to neutrality, heating to distill out the neutralized ethanol, filtering a mixture in the four-mouth flask, washing with distilled water at 100 ℃ for three times in the filtering process, taking out a filter cake, recrystallizing with toluene for three times, and then vacuum drying at 120 ℃ for 2h to finally obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol monomer;

(2) 203g of 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol and 3.9g of tetrabutylammonium bromide are added into a four-necked flask equipped with a stirring device, a reflux condenser, a thermometer, a nitrogen pipe and a peristaltic pump feed pipe, nitrogen is introduced, the temperature is controlled to be 40 ℃, 185g of epichlorohydrin is dripped into the four-necked flask by controlling the feeding flow rate through a peristaltic pump in 2h, reaction is carried out for 2h, at the moment, an intermediate 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] propyl chlorohydrin ether is generated in the flask, then the temperature is reduced and controlled to be 25 ℃, 167g of 48% sodium hydroxide solution is dripped into the four-necked flask by a peristaltic pump in 2h, the obtained liquid is filtered and washed, and after the excessive epichlorohydrin is removed by reduced pressure distillation, 6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether is obtained;

(3) 259g of the 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether was added into a three-neck flask equipped with a stirring device, a reflux condenser, a thermometer and a nitrogen pipe, nitrogen was introduced, 0.5g of platinum catalyst was added, 142g of tetramethyl dihydro disiloxane was further added, the temperature was raised to 100 ℃, and the reaction was carried out for 2 hours, thereby obtaining 389g of 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl dihydro disiloxane) ] glycidyl ether;

(4) 389g of the above 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl-monohydrodisiloxy) ] glycidyl ether was charged into a three-necked flask equipped with a stirring device, a reflux condenser, a thermometer and a nitrogen tube, nitrogen gas was introduced, 0.5g of platinum catalyst was added, 114g of allyl glycidyl ether was further added, and the mixture was heated to 100℃and reacted for 2 hours to give 501g (TGEF) of 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl-disiloxy) ] -tetraglycidyl ether.

Example 1

12g of EXA-830CRP and 1g of bismaleimide resin are firstly added into a three-neck flask equipped with a stirring device, a vacuum tube and a thermometer, the temperature is increased to 155 ℃, and the mixture is stirred in vacuum, melted and dispersed until the liquid is clear. Then 7g of EXA-830CRP, 5g of TGEF,1g of KBM-403 and 1g of JSLD6909 are added into a three-neck flask and stirred for 1h under vacuum at normal temperature. Then 65g of SE6050-SEJ are added, the temperature is raised to 90℃and the mixture is stirred for 4h under vacuum. After cooling to 25 ℃, the mixture was subjected to three-roll milling.

Adding 92g of the three-roller ground underfill premix, 1g of AC1203 and 7g of E-100 into the three-neck flask again, and vacuum stirring for 1h at the temperature of 25-30 ℃ to obtain the underfill of the example 1.

Example 2

12g of EXA-830CRP and 2g of bismaleimide resin are firstly added into a three-neck flask equipped with a stirring device, a vacuum tube and a thermometer, the temperature is increased to 155 ℃, and the mixture is stirred in vacuum, melted and dispersed until the liquid is clear. Then 6gEXA-830CRP, 5g TGEF,1g KBM-403, 1g JSLD6909 were added to the three-necked flask and stirred under vacuum at room temperature for 1h. Then 65g of SE6050-SEJ are added, the temperature is raised to 90℃and the mixture is stirred for 4h under vacuum. After cooling to 25 ℃, the mixture was subjected to three-roll milling.

The underfill of example 2 was obtained by adding 92g of the three-roll-milled underfill premix, 1g of AC1203, and 7g of E-100 into a three-neck flask again, maintaining the temperature at 25 to 30℃and stirring in vacuo for 1 hour.

Comparative example 1

Into a three-necked flask equipped with a stirring device, a vacuum tube and a thermometer, 25g of 830CRP, 1g of KBM-403 and 1g of JSLD6909 were charged, followed by stirring at room temperature under vacuum for 1 hour. Then 65g of SE6050-SEJ are added, the temperature is raised to 90℃and the mixture is stirred for 4h under vacuum. After cooling to 25 ℃, the mixture was subjected to three-roll milling.

Adding 92g of the three-roller ground underfill premix, 1g of AC1203 and 7g of E-100 into the three-neck flask again, and vacuum stirring for 1h at the temperature of 25-30 ℃ to obtain the underfill of the comparative example 1.

Comparative example 2

Into a three-necked flask equipped with a stirring device, a vacuum tube and a thermometer, 20g of 830CRP, 5g of MX-125, 1g of KBM-403 and 1g of JSLD6909 were charged, followed by stirring at room temperature under vacuum for 1 hour. Then 65g of SE6050-SEJ are added, the temperature is raised to 90℃and the mixture is stirred for 4h under vacuum. After cooling to 25 ℃, the mixture was subjected to three-roll milling.

Adding 92g of the three-roller ground underfill premix, 1g of AC1203 and 7g of E-100 into the three-neck flask again, and vacuum stirring for 1h at the temperature of 25-30 ℃ to obtain the underfill of the comparative example 2.

Comparative example 3

Adding 12g of EXA-830CRP and 1g of bismaleimide resin into a three-neck flask equipped with a stirring device, a vacuum tube and a thermometer, heating to 155 ℃, and stirring in vacuum, melting and dispersing until the liquid is clear; then 12gEXA-830CRP, 1g KBM-403 and 1g JSLD6909 are added into a three-neck flask and stirred for 1h under normal temperature and vacuum; then 65g of SE6050-SEJ is added, the temperature is raised to 90 ℃, and the mixture is stirred for 4 hours in vacuum; after cooling to 25 ℃, the mixture is subjected to three-roll grinding;

adding 92g of the three-roller ground underfill premix, 1g of AC1203 and 7g of E-100 into the three-neck flask again, and vacuum stirring for 1h at the temperature of 25-30 ℃ to obtain the underfill of the comparative example 3.

Comparative example 4

Into a three-necked flask equipped with a stirring device, a vacuum tube and a thermometer, 22g of EXA-830CRP, 3g of TGEF,1g of KBM-403 and 1g of JSLD6909 were charged, followed by stirring at room temperature under vacuum for 1 hour. Then 65g of SE6050-SEJ are added, the temperature is raised to 90℃and the mixture is stirred for 4h under vacuum. After cooling to 25 ℃, the mixture was subjected to three-roll milling.

Adding 92g of the three-roller ground underfill premix, 1g of AC1203 and 7g of E-100 into the three-neck flask again, and vacuum stirring for 1h at the temperature of 25-30 ℃ to obtain the underfill of the comparative example 4.

Comparative example 5

Into a three-necked flask equipped with a stirring device, a vacuum tube and a thermometer, 20g of EXA-830CRP, 5g of TGEF,1g of KBM-403 and 1g of JSLD6909 were charged, followed by stirring at room temperature under vacuum for 1 hour. Then 65g of SE6050-SEJ are added, the temperature is raised to 90℃and the mixture is stirred for 4h under vacuum. After cooling to 25 ℃, the mixture was subjected to three-roll milling.

Adding 92g of the three-roller ground underfill premix, 1g of AC1203 and 7g of E-100 into the three-neck flask again, and vacuum stirring for 1h at the temperature of 25-30 ℃ to obtain the underfill of the comparative example 5.

The formulations of the examples and comparative examples are shown in Table 1.

Table 1 formulations (parts by weight) of examples and comparative examples

Testing

Silicon surface adhesion test: and (3) curing the underfill on the surface of the silicon wafer through a custom die to form a pudding shape, then setting the temperature of a platform to 260 ℃ by using a DAGE 4000 tester, and pushing the pudding-shaped glue block from the surface of the silicon wafer to drop, wherein the force value at the moment of drop is the adhesion force of the underfill on the surface of the silicon wafer. The data in table 2 is a list of the silicon surface adhesion data for the examples and comparative examples.

Other tests: tg (DMA) and storage modulus of the cured material were measured using the method of ASTM D7028, the coefficients of thermal expansion (CTE 1 and CTE 2) of the cured material were measured using the method of GB/T36800.2-2018, and the flexural strength and flexural modulus of the cured material were measured using the method of GB/T9341-2008. The data in table 2 list other test data for the examples and comparative examples.

Table 2 comparison of the main properties of examples and comparative examples

As shown in the data in table 2, comparative example 1 is the most basic chip-scale underfill formulation, and comparative example 2 is the traditional core-shell toughening treatment performed on the basic formulation, as seen by the decrease in high temperature modulus and increase in K1C compared to comparative example 1.

In comparative example 3, only a low molecular weight bismaleimide resin (BMI) was added, and the modulus was slightly increased compared with comparative examples 1 and 2, the adhesive decay rate at 260℃after uHast was decreased, the adhesive decay rate at 260℃after HTST 1000h was decreased, and the K1C toughness parameter and the elongation at break toughness parameter at 245℃were decreased, both of which were related to the introduction of a rigid group to the maleic amide bond contained in BMI.

The addition of 3% and 5% of self-synthesized TGEF in comparative examples 4 and 5, respectively, compared with comparative examples 1 and 2, has slightly reduced modulus, reduced adhesive decay rate at 260 ℃ after Hast, reduced adhesive decay rate at 260 ℃ after HTST 1000h, and increased K1C toughness parameter and 245 ℃ elongation at break toughness parameter, which are related to the introduction of polyfunctional epoxy groups, siloxane soft segments, furan groups and phenyl groups into the maleic amide bonds contained in the self-synthesized TGEF.

Examples 1 and 5 incorporated both a self-synthesized TGEF and a low molecular weight BMI, which significantly reduced the 300 ℃ modulus and significantly attenuated the 300 ℃ adhesion, as compared to comparative examples 1 and 2, both of which were associated with the presence of a furan group in the self-synthesized TGEF and a reversible decomposition of a maleic amide linkage in the BMI at high temperatures (300 ℃) and with the silicone soft segment and the polyether linkages in the self-synthesized TGEF. Also, the 260 ℃ adhesive decay rate after uHast and 260 ℃ adhesive decay rate after HTST 1000h are still at low levels, which is related to furan groups in TGRF, phenyl groups, and maleic amide bonds in BMI, and also indicate that although there is a high temperature (300 ℃) reversible decomposition from furan groups in TGEF and maleic amide bonds in BMI, the temperatures in UHast and HTST (130 ℃ and 150 ℃ respectively) are commonly used in semiconductor package reliability testing are not affected. Also, the K1C toughness parameter and the elongation at break toughness parameter at 245℃are elevated, which is related to the siloxane soft segments and the polyether linkages in the self-synthesized TGEF.

Comparing example 1 with example 2, when the low molecular BMI amount is 2%, the K1C toughness parameter and 245 ℃ elongation at break toughness parameter are slightly reduced and the viscosity is increased, although the 260 ℃ adhesive force attenuation ratio after uHast and 260 ℃ adhesive force attenuation ratio after HTST 1000h are further reduced. Thus, combining the above properties, the formulation represented in example 2 is the one with the best performance in this patent.

The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims (10)

1. The reworkable toughening chip-level underfill is characterized by comprising the following components in parts by weight:

15-25 parts of bisphenol F type epoxy resin, 3-8 parts of tetraglycidyl ether containing furan groups which is synthesized autonomously, 0.5-2 parts of bismaleimide resin, 0.5-1.5 parts of silane coupling agent, 0.5-1.5 parts of leveling agent, 0.5-1.5 parts of black paste, 60-70 parts of spherical silicon micro powder and 5-15 parts of curing agent.

2. The reworkable chip-level underfill adhesive according to claim 1, wherein the furan group-containing tetraglycidyl ether is 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyldisiloxane yl) ] -tetraglycidyl ether.

3. The reworkable chip-level underfill according to claim 2, wherein said furan group-containing tetraglycidyl ether is prepared by the following method:

(1) Taking alpha-furaldehyde, 2-methoxy-4- (2-propenyl) phenol as a first step of reaction monomer, xylene as a solvent and methylimidazole as a catalyst, and performing condensation reaction to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol;

(2) Taking 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol and epichlorohydrin as a second step reaction monomer, taking tetrabutylammonium bromide as a phase transfer catalyst, performing ring opening reaction to obtain an intermediate 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] propyl chlorohydrin ether, adding sodium hydroxide, and performing closed-loop reaction to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether;

(3) Taking 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether and tetramethyl dihydro disiloxane as a third step reaction monomer, adding a platinum catalyst, and performing a first addition reaction to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl dihydro disiloxane) ] glycidyl ether;

(4) 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl-hydrogen disiloxane) ] glycidyl ether and propenyl glycidyl ether are taken as a fourth step reaction monomer, a platinum catalyst is added, and the second addition reaction is carried out to obtain 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl disiloxane) ] -tetraglycidyl ether.

4. The reworkable toughened chip-level underfill according to claim 3, wherein in step (1), the molar ratio of α -furaldehyde to 2-methoxy-4- (2-propenyl) phenol is 1:1 to 1:5, the mass ratio of methylimidazole to the first step reaction monomer is 0.1 to 10:100, and the mass ratio of xylene to the first step reaction monomer is 40 to 80:100.

5. The reworkable toughened chip-level underfill according to claim 3, wherein in step (2), the molar ratio of 6,6'- (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] phenol to epichlorohydrin is 1:2-20, the molar ratio of 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] propylchlorohydrin ether to sodium hydroxide is 1:2-10, and the mass ratio of tetrabutylammonium bromide to the second step reaction monomer is 0.1-2:100.

6. The reworkable chip-level underfill adhesive according to claim 3, wherein in step (3), the molar ratio of 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-allyl) ] -diglycidyl ether to tetramethyl dihydrodisiloxane is 1:2-10.

7. The reworkable chip-level underfill adhesive according to claim 3, wherein in step (4), the molar ratio of 6,6' - (furan-2-methylene) -bis [ (2-methoxy) - (4-tetramethyl-mono-hydro-disiloxane) ] glycidyl ether to propenyl glycidyl ether is 1:2-10.

8. The reworkable chip-scale underfill according to claim 3, wherein the condensation reaction temperature in step (1) is 50-120 ℃ and the condensation reaction time is 1-20 hours; the ring-opening reaction temperature in the step (2) is 20-120 ℃, the ring-opening reaction time is 1-10 hours, the ring-closing reaction temperature is 20-50 ℃, and the ring-closing reaction time is 1-10 hours; the first addition reaction temperature in the step (3) is 50-100 ℃, and the first addition reaction time is 1-10 hours; the second addition reaction temperature in the step (4) is 50-100 ℃, and the second addition reaction time is 1-10 hours.

9. The reworkable toughened chip-level underfill according to claim 1, wherein the molecular weight of the bismaleimide resin is 500-5000, the bisphenol F epoxy resin is EXA-830CRP of the DIC corporation of japan, the silane coupling agent is KBM-403 of the letter company of japan, the leveling agent is AC1203 of the samsuna petrochemical industry of Jiangsu sea, the black paste is JSLD6909 of a new material of gansheng, the spherical fine silicon powder is SE6050-SEJ of the jac dema corporation of japan, and the curing agent is E-100 of the eastern chemical industry of Jiangsu elegance.

10. A method of preparing the reworkable toughened chip-level underfill according to any of claims 1 to 9, comprising the steps of:

s1, carrying out melt dispersion on bisphenol F type epoxy resin and bismaleimide resin under a vacuum condition of 100-200 ℃ to obtain premixed resin;

s2, mixing bisphenol F epoxy resin, premix resin, tetraglycidyl ether containing furan groups, a silane coupling agent and black paste, stirring for 1h, adding spherical silicon micropowder, heating and stirring for 2-10h at 70-90 ℃ in vacuum, and grinding by three rollers after cooling to normal temperature to form an underfill premix;

and S3, blending the underfill premix, the leveling agent and the curing agent, and stirring for 1-2 hours at the temperature of 25-30 ℃ to obtain the underfill.