CN112457807A

CN112457807A - Preparation method of chip-level underfill material with excellent thermal stability

Info

Publication number: CN112457807A
Application number: CN202011272025.9A
Authority: CN
Inventors: 金涛; 王建斌; 陈田安
Original assignee: Yantai Darbond Technology Co Ltd
Current assignee: Yantai Darbond Technology Co Ltd
Priority date: 2020-11-14
Filing date: 2020-11-14
Publication date: 2021-03-09

Abstract

The invention relates to a preparation method of a chip-level underfill material with excellent thermal stability, which comprises the following steps: 15-20g of epoxy resin, 2-5g of polyfunctional epoxy resin, 2-5g of toughening type epoxy resin, 0.4-0.8g of silane coupling agent and 0.2-0.6g of carbon black are stirred for 2 hours, then 65-70g of spherical silicon dioxide is added in three times, the temperature is set to be 80 ℃, and the mixture is heated and stirred for 4 hours; adding 0.5-1g of heat stabilizer, and stirring for 1 h; adding 8-10g of amine curing agent, stirring for 2h, and finishing the preparation process. The invention introduces the heat stabilizer into the formula of the chip-level bottom filling material, and can obviously improve the stability of the chip-level bottom filling material in the production, preparation and practical application processes.

Description

Preparation method of chip-level underfill material with excellent thermal stability

Technical Field

The invention relates to a chip-level underfill material with excellent thermal stability, and belongs to the field of single-component epoxy electronic adhesive materials.

Background

In the chip packaging technology, a bonding layer of an IC chip and an organic substrate is composed of a large number of welding spots with micro sizes, the welding spots have poor deformation adaptability and are extremely sensitive to thermal stress, and the problem of structural reliability is more prominent. The use of polymer underfill to improve the reliability of packaged chips is a new approach developed in recent years. The method is economical and easy, and during the chip packaging process, the Underfill material (Underfill) is gradually solidified and formed in the slit between the IC chip and the organic substrate by thermosetting action, and the connected welding spots are protected. Meanwhile, the impact load can be effectively reduced, 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 chip packaging structure has great development potential.

The chip-level underfill material is a single-component liquid material before being cured at normal temperature, and mainly comprises epoxy resin and spherical silicon dioxide with a large amount of addition. One of the primary functions of the chip-level underfill material is to adhere the entire IC chip to the substrate to reduce the thermal stress of the solder ball joints in practice. Finally, the Coefficient of Thermal Expansion (CTE) of the whole composite material system is between the CTE of the IC chip and the CTE of the substrate, so that the reliability is improved. The chip-level underfill material can effectively improve the mechanical strength of the solder joints, thereby improving the service life of the chip.

Due to the whole formula system of the chip-level underfill material, the stability of the chip-level underfill material is deteriorated after the curing agent is added in the production process. Particularly, in the using process, the overall viscosity can be gradually increased along with the prolonging of the using time under the normal temperature environment. When the chip is flowed through a larger chip, the viscosity of the chip-level underfill material is increased rapidly due to the increase of viscosity at the later stage of flow filling, and even a gel phenomenon occurs. The problem of poor stability can directly affect the shelf life of the chip-level underfill material, and the risk of defects such as bubbles and voids in the package also exists. Therefore, on the premise of ensuring that other excellent properties of the chip-level underfill material are not changed, the thermal stability of the chip-level underfill material is improved, and the method is one of the directions for optimizing and perfecting the chip-level underfill material.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the preparation method of the heat stabilizer for the chip-level underfill material is provided, the heat stabilizer is properly added into the preparation of the formula of the chip-level underfill material, so that the viscosity stability of the chip-level underfill material in the production preparation, normal-temperature placement and actual application processes is improved, and the viscosity change of the chip-level underfill material in the actual process is reduced, so that the stability of the chip-level underfill material in the production and application processes is improved.

The preparation method of the self-made heat stabilizer comprises the following steps:

(1) preparation of cinnamic aldehyde barbituric acid (CBA):

adding 64.04 barbituric acid and distilled water into a 250mL three-necked bottle with a condenser, a thermometer and a stirrer, stirring and heating, gradually dissolving the barbituric acid into a light yellow transparent solution along with the rise of the temperature, adding 66.1 cinnamaldehyde, generating a yellow solid within 1-2 min, maintaining the reaction temperature, continuing stirring for 45min, stopping the reaction, washing with hot water, carrying out suction filtration while hot, and drying in a forced air drying oven to obtain yellow powder: cinnamic aldehyde barbituric acid CBA;

synthetic reaction equation of cinnamic aldehyde barbituric acid

(2) Preparation of Zinc cinnamaldehyde barbiturate (CBA-Zn):

60.56g of CBA, adding into 400ml of deionized water, continuously stirring and heating to 90 ℃ until the CBA is completely dissolved and clarified; 35.12g of zinc acetate hydrate is added into the CBA solution twice and reacts for 1 hour to generate a large amount of beige precipitate; washing the filtrate with deionized water to neutrality, and drying at 90 ℃ to obtain CBA-Zn;

(3) preparing a heat stabilizer:

40g of CBA-Zn, 16g of calcium stearate and 30g of polypropylene glycol, and uniformly dispersing the components by a roller to obtain the heat stabilizer.

The invention also provides a preparation method of the chip-level underfill material with excellent thermal stability, which comprises the following steps:

15-20g of epoxy resin, 2-5g of polyfunctional epoxy resin, 2-5g of toughening type epoxy resin, 0.4-0.8g of silane coupling agent and 0.2-0.6g of carbon black are added into a high-speed planetary stirrer, after stirring for 2 hours, 65-70g of spherical silicon dioxide is added in three times, the temperature is set to 80 ℃, the mixture is heated and stirred for 4 hours, the stirrer is closed and heated, condensed water is introduced to cool the stirrer to the normal temperature, 0.5-1g of heat stabilizer is added, the mixture is stirred for 1 hour, 8-10g of amine curing agent is added, the preparation process is finished after the temperature is controlled and the stirring is maintained at the normal temperature for 2 hours, and the vacuum degree is not lower than-0.08 MPa in.

The epoxy resin comprises: EXA-830CRP, EXA-830LVP, EXA-835LV, HP-4032D of Japan DIC, KF-8110 of Korea Koron, YLSE-900S of Korea GLK, XP1080 of Shanghai Zhongsi, 370 resin of Shanghai Huayi, one or more of them are compounded;

the multifunctional epoxy resin includes: ELM-100H of Sumitomo Japan, MY720 and MY0500 of Hensman, SW-0510, SW-70 and SW-80 of Hunan Severv, and one or more of the components are compounded;

the toughened epoxy resin comprises: one or more of MX125, MX153, MX553, MX960, and MX267 of Mitsuo, Japan, and BPA328 and BPF307 of Nippon Shokubai company;

the silane coupling agent includes: gamma-aminopropyl triethoxysilane (KH550), gamma-mercaptopropyl trimethoxysilane (KH570), gamma-mercaptopropyl triethoxysilane (KH580), gamma-glycidoxypropyl trimethoxysilane (KH560) and gamma-aminopropyl trimethoxysilane (KH 540).

The spherical silica includes: one or more of FE920ASQ, FEB25G-SED, SC220G-SQ, SE6050-STE, SO-E2 and SO-E2/24C of Yadama;

the amine curing agent includes: 4,4 '-diamino-3, 3' -diethyl diphenylmethane, diethyl toluenediamine, diamino diphenyl sulfone, m-amino methylamine, xylylene diamine tripolymer, dibenzyl amino ether and diethyl toluenediamine.

The invention has the beneficial effects that: the heat stabilizer is introduced into the formula of the chip-level underfill material, so that the stability of the chip-level underfill material in the production, preparation and practical application processes can be obviously improved. That is, the viscosity gradually increases over time due to the slow reaction of the epoxy resin with the amine curing agent. By improving the stability, the quality guarantee period of the chip-level underfill material can be prolonged and the open time can be prolonged on the basis of not changing other excellent performances of the chip-level underfill material, so that the excellent performances of the chip-level underfill material can be more improved. The novel and special point in the patent is that the cinnamic aldehyde barbituric acid and the heat stabilizer thereof are synthesized by self, the preparation process is simple, the operation is easy, no special equipment is needed, and the cost can be reduced.

The conventional chip-scale underfill material can be normally used within a specified viscosity rise of 30% at 25 ℃ with a recommended service time of 8 h. The suggested service time of the chip-scale underfill material with the thermal stabilizer introduced into the formula can be increased to more than 24h at 25 ℃, and the gel time at 110 ℃ is prolonged by 1 time compared with the conventional chip-scale underfill material.

Detailed Description

The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

Example 1

18g of EXA-830LVP resin, 5.5g of SW-0510 resin, 2g of MX125 resin, 0.5g of KH560 silane coupling agent and 0.5g of carbon black are added into a high-speed planetary stirrer, after stirring for 2 hours, 65g of FE920ASQ silicon dioxide is added into the stirrer for three times, the temperature is set to be 80 ℃, the stirring is carried out for 4 hours by heating, the heating is closed, the stirrer is cooled to the normal temperature by introducing condensed water, 0.2g of self-made heat stabilizer is added, the stirring is carried out for 1 hour, 8g of curing agent diethyl toluene diamine is added, after the stirring is carried out for 2 hours under the condition of controlling the temperature, the preparation process is finished, and the vacuum degree is kept to.

Example 2

18g of EXA-830LVP resin, 5.5g of SW-0510 resin, 2g of MX125 resin, 0.5g of KH560 silane coupling agent and 0.5g of carbon black are added into a high-speed planetary stirrer, after stirring for 2 hours, 65g of FE920ASQ silicon dioxide is added into the stirrer for three times, the temperature is set to be 80 ℃, the stirring is carried out for 4 hours by heating, the heating is closed, the stirrer is cooled to the normal temperature by introducing condensed water, 0.5g of self-made heat stabilizer is added, the stirring is carried out for 1 hour, 8g of curing agent diethyl toluene diamine is added, after the stirring is carried out for 2 hours under the condition of controlling the temperature, the preparation process is finished, and the vacuum degree is kept to.

Example 3

18g of EXA-830LVP resin, 5.5g of SW-0510 resin, 2g of MX125 resin, 0.5g of KH560 silane coupling agent and 0.5g of carbon black are added into a high-speed planetary stirrer, after stirring for 2 hours, 65g of FE920ASQ silicon dioxide is added into the stirrer in three times, the temperature is set to be 80 ℃, the heating and stirring are carried out for 4 hours, the heating is closed, the stirrer is cooled to the normal temperature by introducing condensed water, 1g of self-made heat stabilizer is added, the stirring is carried out for 1 hour, 8g of curing agent diethyl toluene diamine is added, after the stirring is carried out for 2 hours at the normal temperature, the preparation process is finished, and the whole process is kept at the vacuum degree.

Example 4

The preparation method comprises the following steps of adding 20g of KF-8110 resin, 5g of XP1080 resin, 1g of MX125 resin, 0.5g of KH560 silane coupling agent and 0.5g of carbon black into a high-speed planetary stirrer, stirring for 2 hours, adding 65g of FEB25G-SED silicon dioxide three times, setting the temperature to be 80 ℃, heating and stirring for 4 hours, closing heating, cooling the stirrer to the normal temperature through condensed water, adding 0.2g of self-made heat stabilizer, stirring for 1 hour, adding 7g of curing agent 4,4 '-diamino-3, 3' -diethyl diphenylmethane, stirring for 2 hours at the normal temperature under controlled temperature, finishing the preparation process, and keeping the vacuum degree not lower than-0.08 MPa in the whole process.

Example 5

The preparation method comprises the following steps of adding 20g of KF-8110 resin, 5g of XP1080 resin, 1g of MX125 resin, 0.5g of KH560 silane coupling agent and 0.5g of carbon black into a high-speed planetary stirrer, stirring for 2 hours, adding 65g of FEB25G-SED silicon dioxide three times, setting the temperature to be 80 ℃, heating and stirring for 4 hours, closing heating, cooling the stirrer to the normal temperature through condensed water, adding 0.5g of self-made heat stabilizer, stirring for 1 hour, adding 7g of curing agent 4,4 '-diamino-3, 3' -diethyl diphenylmethane, stirring for 2 hours at the normal temperature under controlled temperature, finishing the preparation process, and keeping the vacuum degree not lower than-0.08 MPa in the whole process.

Example 6

The preparation method comprises the following steps of adding 20g of KF-8110 resin, 5g of XP1080 resin, 1g of MX125 resin, 0.5g of KH560 silane coupling agent and 0.5g of carbon black into a high-speed planetary stirrer, stirring for 2 hours, adding 65g of FEB25G-SED silicon dioxide into the mixture three times, setting the temperature to be 80 ℃, heating and stirring for 4 hours, closing the heating, cooling the stirrer to the normal temperature through condensed water, adding 1g of self-made heat stabilizer, stirring for 1 hour, adding 7g of curing agent 4,4 '-diamino-3, 3' -diethyl diphenylmethane, stirring for 2 hours at the normal temperature under controlled temperature, finishing the preparation process, and keeping the vacuum degree not lower than-0.08 MPa in the whole process.

Comparative example 1

Adding 18g of EXA-830LVP resin, 5.5g of SW-0510 resin, 2g of MX125 resin, 0.5g of KH560 silane coupling agent and 0.5g of carbon black into a high-speed planetary stirrer, stirring for 2 hours, adding 65g of FE920ASQ silicon dioxide into the stirrer three times, setting the temperature to be 80 ℃, heating and stirring for 4 hours, closing the heating, cooling the stirrer to the normal temperature by introducing condensed water, adding 8g of curing agent 4,4 '-diamino-3, 3' -diethyl diphenylmethane, stirring for 2 hours at the normal temperature, finishing the preparation process, and keeping the vacuum degree to be not lower than-0.08 MPa in the whole process.

Comparative example 2

KF-8110 resin 20g, XP1080 resin 5g, MX125 resin 1g, KH560 silane coupling agent 0.5g, carbon black 0.5g, add into high-speed planet agitator, stir for 2 hours, add FEB25G-SED silica 65g into three times, set temperature to 80 ℃, heat and stir for 4 hours, close the heating, let in the comdenstion water and drop to the agitator to the normal temperature, add 7g curing agent diethyl toluene diamine, control the temperature and maintain and stir for 2 hours at normal temperature, finish the preparation process, the whole process keeps the vacuum degree not less than-0.08 Mpa.

Testing

The viscosity and viscosity tracking test results of the products obtained in examples 1 to 6 and comparative examples 1 and 2 are shown in table 1; the results of the pudding mold bond strength and the thrust after high temperature and high humidity test are shown in table 2.

Viscosity and viscosity tracking test: measuring at room temperature for 20s with Haake viscometer (Thermofeisher, USA) and C20/2 rotor^-1Viscosity of water (VI). The prepared chip-level underfill material is placed at normal temperature, the viscosity change of every 8 hours is measured within 24 hours, and the viscosity change rate is tracked.

Testing the adhesive strength of the pudding die: injecting the prepared chip-level bottom filling material into a preheated pudding die clamp, wherein a silicon wafer is placed in the clamp; injecting, placing in an oven, heating to 165 deg.C from room temperature, and curing at constant temperature2 h; cooling, demolding to obtain CUF solidified pudding mold adhered to the surface of the silicon wafer, wherein the contact area of the pudding mold and the silicon wafer is 24-25mm²(ii) a After 24h of constant temperature in the laboratory for testing thrust, a thrust test was carried out at a thrust rate of 100 μm/s and a thrust height of 50 μm.

High-temperature and high-humidity treatment of a pudding die: and (3) placing the cured pudding mould in a high-temperature high-humidity test box, wherein the temperature is 85 ℃ and the humidity is 85%. After standing for 7 days, the specimen was taken out and subjected to a thrust test. The degree of attenuation was compared with the initial thrust without high-temperature and high-humidity treatment.

TABLE 1 viscosity and Normal temperature viscosity tracking test results

TABLE 2 Butt die adhesion thrust test

As can be seen from the data in Table 1, after the self-made heat stabilizer is added into the formula, the viscosity change rate is obviously reduced within 24 hours, namely the room temperature stability is more excellent than that of a comparative formula without the self-made heat stabilizer. As can be seen from the data in table 2, the deterioration of the adhesive strength after high temperature and high humidity is large when the self-made heat stabilizer is added to the formulation as compared to the comparative example. Therefore, the addition of the homemade stabilizer is recommended to be 0.5% of the whole formulation system.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A method for preparing a chip-scale underfill material with excellent thermal stability, comprising: 15-20g of epoxy resin, 2-5g of polyfunctional epoxy resin, 2-5g of toughened epoxy resin, 0.4-0.8g of silane coupling agent and 0.2-0.6g of carbon black are added into a high-speed planetary stirrer, after stirring for 2 hours, 65-70g of spherical silicon dioxide is added in three times, the temperature is set to 80 ℃, the heating and stirring are carried out for 4 hours, the stirrer is closed to heat, the stirrer is cooled to the normal temperature by condensed water, 0.5-1g of heat stabilizer is added, the stirring is carried out for 1 hour, 8-10g of amine curing agent is added, after the stirring is carried out for 2 hours under the condition of controlling the temperature and maintaining the normal temperature, the preparation process is ended, and the vacuum degree is not lower than-;

the preparation method of the heat stabilizer comprises the following steps:

(1) preparation of cinnamaldehyde barbituric acid CBA:

adding 64.04g of barbituric acid and distilled water into a 250mL three-necked bottle provided with a condenser, a thermometer and a stirrer, stirring and heating, gradually dissolving the barbituric acid into a light yellow transparent solution along with the rise of the temperature, adding 66.1g of cinnamaldehyde, generating a yellow solid within 1-2 min, maintaining the reaction temperature, continuing stirring for 45min, terminating the reaction, washing with hot water, carrying out suction filtration while the solution is hot, and drying in a forced air drying box to obtain a yellow powder: cinnamic aldehyde barbituric acid CBA;

(2) preparing zinc cinnamaldehyde barbiturate CBA-Zn:

60.56g of CBA, adding into 400ml of deionized water, continuously stirring and heating to 90 ℃ until the CBA is completely dissolved and clarified; 35.12g of zinc acetate dihydrate are added into the CBA solution twice and react for 1 hour to generate a large amount of beige precipitate; washing the filtrate with deionized water to neutrality, and drying at 90 ℃ to obtain CBA-Zn;

(3) preparing a heat stabilizer:

2. The method of manufacturing according to claim 1, wherein the epoxy resin includes: one or more of EXA-830CRP, EXA-830LVP, EXA-835LV, HP-4032D of DIC of Japan, KF-8110 of Korea, YLSE-900S of GLK of Korea, XP1080 of Shanghai Zhongsi, and 370 resin of Shanghai Huayi.

3. The production method according to claim 1, wherein the multifunctional epoxy resin comprises: ELM-100H of Sumitomo Japan, MY720 and MY0500 of Hensman, SW-0510, SW-70 and SW-80 of Hunan Severv; the toughened epoxy resin comprises: one or more of MX125, MX153, MX553, MX960, and MX267 of Mitsuo, Japan, and BPA328 and BPF307 of Nippon Shokubai company.

4. The production method according to claim 1, wherein the silane coupling agent comprises: one or more of gamma-aminopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane and gamma-aminopropyltrimethoxysilane are compounded;