TWI642746B - An underfill composition, filling method and electrical component by using thereof - Google Patents

Abstract

The present invention provides an underfill composition comprising an epoxy resin, a modified amine hardener, and an inorganic filler. The underfill composition of the present invention does not require additional stress releasing agents and reinforcing agents, does not cause embrittlement problems after hardening, has elasticity and toughness, and can improve the reliability of the packaged electronic components.

Description

Underfill composition and underfill method and electronic assembly component using same

The present invention relates to an underfill composition, particularly an underfill composition between a semiconductor wafer and a package substrate.

The increasingly sophisticated and miniaturized electronic products have led to the miniaturization of integrated circuits, and how to effectively package wafers in miniaturized electronic components is one of the important developments in packaging technology today. When the chip is packaged, the thermal expansion coefficients of the wafer and the substrate are different, and the crystal grains of the bonded wafer are subjected to uneven stress between the substrates, forming a thin intermediate portion of the package and a thick portion of the periphery, so that the packaged wafer is subjected to thermal cycle test (ie, Under the thermal shock conversion, the surrounding crystal grains are easily peeled off, and the package reliability is lowered. In order to solve this problem, an underfill is generally added between the wafer and the substrate, and the underfill is used to disperse and absorb the stress on the surface of the wafer, thereby improving the reliability of the product.

Underfills are generally preferred for their high flow, high glass transition temperature and low coefficient of thermal expansion. Filler filling methods include capillary flow, non-flowing primer filling, die-cast primer filling, and wafer-level primer filling.

In special cases, such as when the package wafer test fails, the wafer must be removed from the substrate and the underfill must be removed and repackaged. In order to comply with this In general, the underfill is also required to have a release property, and can be completely peeled off from between the wafer and the substrate when it needs to be removed.

The existing underfill composition is mainly composed of an epoxy resin and cerium oxide. However, the epoxy resin has poor elasticity after hardening, and there is often a problem of excessive hardening and embrittlement, which reduces the reliability of the underfill, and causes the underfill to have no underfill during the thermal cycle test. Slightly peeled off and not adhered between the wafer and the substrate, even cracked and layered. In order to solve this problem, an auxiliary agent such as a stress release agent or a reinforcing agent is generally added in the epoxy resin, but it takes a lot of time to test the material cost to find a suitable adjuvant and a formulation ratio. Add to. Accordingly, the present inventors have developed an underfill composition having a modified amine hardener and increasing the elasticity and toughness of the underfill after hardening without the addition of an auxiliary agent such as a strain release agent or a reinforcing agent. .

Therefore, the present invention provides an underfill composition comprising an epoxy resin, a modified amine hardener, and an inorganic filler.

In a preferred embodiment, the modified amine hardener is obtained by reacting diglycidyl ether and polyoxypropylene with a molar ratio of 1:1 to 1:3.

In a preferred embodiment, the polyoxypropylene diamine has the structure of the following formula (1): , n is 5~33.

In a preferred embodiment, the polyoxypropylene diamine has a molecular weight of from 400 to 2,000.

In a preferred embodiment, the diglycidyl ether may be selected from the group consisting of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether.

In a preferred embodiment, the diglycidyl ether is bisphenol A diglycidyl ether.

In a preferred embodiment, the epoxy resin, the modified amine hardener, and the inorganic filler have a mass ratio of 5 to 15:10 to 50:40 to 60.

The present invention further provides a method for filling an underfill, comprising the steps of: (1) using a mold holder to fix a wafer and a substrate to form a filling hole between the wafer and the substrate; (2) filling the filling; The cavity is evacuated and uniformly filled with the filling composition as described above, and the filling is completed after heating and solidification.

In a preferred embodiment, the curing conditions are at a temperature of from 140 to 180 ° C for a period of from 40 to 80 minutes.

The invention further provides an electronic assembly component comprising a wafer and a substrate, and the filling composition as described above is filled between the wafer and the substrate.

1‧‧‧ underfill composition

3‧‧‧Modified amine hardener

5‧‧‧2 cerium oxide

7‧‧‧ carbon black

9‧‧‧Epoxy resin

11‧‧‧ Underfill

13‧‧‧ wafer

14‧‧‧ Filling

15‧‧‧ grain

17‧‧‧Substrate

Fig. 1 is an illustration of an underfill of the present invention and a method of filling the same.

In the following, the disclosure of the invention will be specifically described using specific embodiments. However, the disclosure of the present invention is not limited to the following examples.

The present invention provides an underfill composition comprising an epoxy resin, a modified amine hardener, and an inorganic filler. The mass ratio of the epoxy resin, the modified amine curing agent and the inorganic filler is 5 to 15:10 to 50:40 to 60.

The above epoxy resin may be an epoxy resin commonly used for an underfill composition, which comprises a bisphenol A type epoxy resin, a brominated bisphenol A type epoxy resin, a hydrogenated bisphenol A type epoxy resin, and a bisphenol. F type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, rosin modified ring Oxygen resin, novolak type epoxy resin, ether series or polyether series epoxy resin, oxirane ring-containing polybutadiene, polyoxyalkylene epoxy group copolymer resin, etc. Type epoxy resin is preferred.

The above inorganic filler may be an inorganic filler commonly used for an underfill composition, which comprises cerium oxide such as molten cerium oxide or crystalline cerium oxide, titanium oxide, aluminum oxide, cerium oxide, zirconium oxide, zircon, nitrogen. Plutonium, boron nitride, aluminum nitride, magnesium oxide, magnesium silicate, calcium carbonate, barium carbide, potassium titanate, aluminum, magnesium silicate, talc, spinel, glass fiber or mullite .

The above modified amine hardener is obtained by reacting diglycidyl ether and polyoxypropylene with a molar ratio of 1:1 to 1:5, preferably 1:1 to 1:3, more preferably 1:1 to 1 :2. Wherein, the polyoxypropylene has the structure of the following formula (1): , n is 5 to 33; examples include polyether diamine D series (JEFFAMINE D-series) POA400 (n is 5-6, molecular weight 400) and POA2000 (n is 33, molecular weight 2000). Wherein, the diglycidyl ether ether may be selected from the group consisting of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, and preferably bisphenol A diglycidyl ether. .

The above underfill composition may also be added with a coloring agent such as carbon black, an antifoaming agent, an antioxidant or other additives.

The method for filling an underfill according to the present invention comprises the steps of: (1) fixing a wafer and a substrate with a mold holder to form a filling hole between the wafer and the substrate; and (2) vacuuming the filling hole. Pumping and evenly spreading the underfill composition as described above Fill the filling hole, complete the filling after heating and curing. Wherein, the wafer has crystal grains; the curing condition is temperature 140-180 ° C, time 40-80 minutes, such as 140 ° C, 145 ° C, 150 ° C, 155 ° C, 160 ° C, 165 ° C, 170 ° C, 175 ° C Or 180 ° C, and 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes or 80 minutes.

An example of the underfill and the filling method of the present invention is shown in FIG. 1. The underfill composition 1 comprises a modified amine hardener 3, cerium oxide 5, carbon black 7, and epoxy resin 9 Forming the underfill 11; subsequently, fixing a wafer 13 and a substrate 15 using a mold holder, such that a filling hole 14 is formed between the wafer 13 and the substrate 15, and the wafer 13 is attached with a die 15; The hole 14 is evacuated and uniformly filled with the filling hole 14 using, for example, an underfill 11, and the filling is completed after heating and solidification.

The electronic assembly component of the present invention comprises a wafer and a substrate, and the underfill is filled between the wafer and the substrate.

[Specific embodiment]

The following embodiments are not to be considered as limiting the invention in any way. Modifications and variations of the embodiments discussed herein may be made without departing from the spirit and scope of the invention, and still fall within the scope of the invention.

Preparation Example 1. Preparation of a modified amine hardener (polyether diamine POA400-bisphenol A diglycidyl ether (POA400-DGEBA))

50 g of bisphenol A diglycidyl ether (DGEBA epoxy, 147 mmol) and 88.2 g of polyether diamine POA400 (JEFFAMINE D-series POA400, 220 mmol) were placed in a reactor and spun in a reactor at 25 ° C for 24 hours. The modified amine hardener polyether diamine POA400-bisphenol A diglycidyl ether (POA400-DGEBA) is obtained, and the reaction formula of the reaction is as shown in formula (3) Shown.

Preparation Example 2. Preparation of a modified amine hardener (polyether diamine POA2000-bisphenol A diglycidyl ether (POA2000-DGEBA))

50 g of bisphenol A diglycidyl ether (DGEBA epoxy, 147 mmol) and 392 g of polyether diamine POA2000 (JEFFAMINE D-series POA2000, 196 mmol) were placed in a reactor and spun in a reactor at 25 ° C for 24 hours. A modified amine hardener polyether diamine POA2000-bisphenol A diglycidyl ether (POA2000-DGEBA) was obtained, and the reaction formula of the reaction is shown in the formula (3).

Example 1. Underfill composition 1 of the present invention and underfill using the same

Take 10g of bisphenol A epoxy resin (Nanya plastic, NPEL-128), 40g of modified amine hardener of preparation example 1, 50g of cerium oxide (Admatechs, SE2050) and 0.1g of carbon black (Orion, NEROX505, Germany) After mixing uniformly at 25 ° C for 3 minutes, the underfill is obtained. Glue composition 1. Subsequently, the wafer and the substrate are fixed by using a mold holder, a filling hole is formed between the wafer and the substrate, and the filling hole is vacuum-extracted in 25 minutes at 25 ° C and the underfill composition 1 is evenly covered. After the filling, the filling was completed after heating and curing at 165 ° C for 1 hour.

Example 2. Underfill composition 2 of the present invention and underfill using the same

Take 10g of bisphenol A epoxy resin (Nanya Plastics, NPEL-128), 40g of modified amine hardener of Preparation 2, 50g of cerium oxide (Admatechs, SE2050) and 0.1g of carbon black (Orion, NEROX505, Germany) The mixture was uniformly mixed at 25 ° C for 3 minutes to obtain an underfill composition 2. Subsequently, the wafer and the substrate are fixed by using a mold holder, a filling hole is formed between the wafer and the substrate, the filling hole is vacuum-extracted in 25 minutes at 25 ° C, and the underfill composition 2 is evenly covered. After the filling, the underfill was completed after heating and curing at 165 ° C for 1 hour.

Comparative Example. Other underfill compositions and their packages

Take 50g bisphenol A epoxy resin (Nanya plastic, NPEL-128), 50g cerium oxide (Japan Admatechs, SE2050), 5g amine hardener (Degussa, Germany, 100S dicyandiamide), 5g enhancer (Japan Dainippon ink) Chemically DIC, H360) and 0.1 g of carbon black (Orion, NEROX 505, Germany) were uniformly mixed at 25 ° C for 3 minutes to obtain an underfill composition. Subsequently, the wafer and the substrate are fixed by using a mold holder, a filling hole is formed between the wafer and the substrate, the filling hole is vacuum-extracted in 25 minutes at 25 ° C, and the underfill is evenly filled with the filling hole. After that, the filling was completed after heating and curing at 165 ° C for 1 hour.

[thermal cycle test]

The underfill wafers and substrates obtained in Examples 1 and 2 and Comparative Examples were tested for thermal cycling TCB1000 and TCC200 at a Moisture Sensitive Level (MSL) of 3, and observed for hardening. The reliability of the bottom underfill composition is shown in Table 1:

As can be seen from the comparison of Table 1, when the thermal cycle test conditions were MSL3 and TCC200, the underfill hardener of the comparative example was separated and cracked from the substrate, and in contrast, Examples 1 and 2 used the underfill of the present invention. The gel composition, such as the hardened material, remained in its original state under both thermal cycling test conditions and did not separate from the substrate. It can be seen that in the past, an epoxy resin is used in combination with an underfill of a general amine hardener, and the toughness is still poor even when an additional reinforcing agent is added. However, the underfill composition of the present invention is modified. The amine hardener does not require the addition of a stress releasing agent and a reinforcing agent, and does not cause embrittlement after hardening, and has elasticity and toughness. Therefore, the underfill composition of the present invention has high reliability and is not easily deteriorated.

Claims (7)

An underfill composition comprising an epoxy resin, a modified amine hardener and an inorganic filler; the epoxy resin, the modified amine hardener and the inorganic filler have a mass ratio of 5 to 15:10 to 50 : 40~60; wherein the modified amine hardener is obtained by reacting diglycidyl ether and polyoxypropylene diamine with a molar ratio of 1:1 to 1:3, and the polyoxypropylene diamine has the following formula ( 1) Structure: , n is 5~33. The underfill composition as claimed in claim 1, wherein the polyoxypropylenediamine has a molecular weight of from 400 to 2,000. The underfill composition according to any one of claims 1 to 2, wherein the diglycidyl ether is selected from the group consisting of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether The group formed. The underfill composition of claim 3, wherein the diglycidyl ether is bisphenol A diglycidyl ether. A method for filling an underfill, comprising the steps of: (1) fixing a wafer and a substrate with a mold holder to form a filling hole between the wafer and the substrate; and (2) vacuuming the filling hole. And filling the filling hole evenly with the underfill composition as described in any one of claims 1 to 4, and completing the filling after heat curing. The underfill method according to claim 5, wherein the curing condition is a temperature of 140 to 180 ° C and a time of 40 to 80 minutes. An electronic assembly component comprising a wafer and a substrate, the substrate and the substrate being filled with an underfill as claimed in any one of claims 1 to 4.