TW201428055A - Dielectric material with low dielectric loss - Google Patents

Abstract

The invention provides a dielectric material with low dielectric loss.The dielectric material comprises (i) 40 to 80 parts by weight of poly(phenylene ether) having a Mw of 1000 to 7000, a Mn of 1000 to 4000 and Mw/Mn=1.0 to 1.8; (ii) 5 to 30 parts by weight of bismaleimide; and (iii) 5 to 30 parts by weight of polymer additives, wherein the dielectric material has Dk of 3.75 to 4.0 and Df of 0.0025 to 0.0045.The dielectric material is suitably used in prepregs and insulation layers of a circuit board, because it has high Tg, low thermal expansion coefficient, low moisture absorption and excellent dielectric properties such as Dk and Df.

Description

Low dielectric material

The present invention relates to a low dielectric material, particularly to a resin composition.

With the rapid development of wireless transmission products and the leap of high-frequency transmission technology, the materials of existing epoxy resin and phenolic resin systems have been unable to meet advanced applications, especially the demand for high-frequency printed circuit boards.

As a substrate material of a printed circuit board having a low dielectric loss, there is a fluorine-based resin, but such a resin is expensive and difficult to process, and the application is limited to military and aerospace applications. In addition, polyphenylene ether (PPE) resins are preferred resin materials for substrates of high frequency printed circuit boards due to their good mechanical properties and excellent dielectric properties such as dielectric constant (Dk) and dielectric loss (Df).

However, polyphenylene ether is a thermoplastic resin, and its direct use in a copper foil substrate has the following disadvantages: high melt viscosity, difficulty in processing and molding; poor solvent resistance, and easy adhesion of wires in a solvent cleaning environment in a printed circuit board manufacturing process. Not fast or fall off; and the melting point is similar to the glass transition temperature (Tg), and it is difficult to withstand soldering operations above 250 °C in the printed circuit board process. Therefore, PPE has been thermoset modified to meet the requirements of printed circuit boards.

The thermosetting modification of PPE generally has two modes: introducing a crosslinkable reactive group into the molecular structure of PPE to make it a thermosetting resin. Alternatively, other thermoset resins may be introduced by blending modified or interpenetrating network (IPN) techniques to form a blended thermoset composite. However, due to the difference in chemical structure polarity, PPE is often limited in compatibility with the reactive groups or thermosetting resins, poor processing, or loss of the original excellent properties of PPE.

Therefore, how to develop materials with excellent dielectric properties and other characteristics of printed circuit boards, such as high Tg, low coefficient of thermal expansion, and low water absorption, and applied to the manufacture of high frequency printed circuit boards is At this stage, the supplier of printed circuit board materials is eager to solve the problem.

It is an object of the present invention to provide a low dielectric material having excellent dielectric properties, a low coefficient of thermal expansion, and low water absorption.

In order to achieve the above object of the present invention, a low dielectric material comprising: (A) 40 to 80 parts by weight of polyphenylene ether, number average molecular weight (Mn) = 1000 to 4000, weight average molecular weight (Mw) = 1000~ is proposed. 7000, and Mw/Mn = 1.0 to 1.8; (B) 5 to 30 parts by weight of bismaleimide (BMI); and (C) 5 to 30 parts by weight of a polymer additive. The Dk value of the low dielectric material is 3.75~4.0, and the Df value is 0.0025~0.0045.

In the low dielectric material of the present invention, the structural formula of the polyphenylene ether is as follows:






Wherein Y can be at least one carbon, at least one oxygen, at least one benzene ring or a combination of the above.

In the low dielectric material of the present invention, the bismaleimide is selected from at least one of the following groups:

Phenylmethane maleimide



Where n=≧1;

Bisphenol A diphenyl ether bismaleimide

3,3'-Dimethyl-5,5'-diethyl-4,4'-diphenylethane bismaleimide (3,3'-dimethyl-5,5'-diethyl-4, 4'-diphenylethane bismaleimide)

1,6-Bismaleimide-(2,2,4-trimethyl)hexane (1,6-bismaleimide-(2,2,4-trimethyl)hexane)

In the low dielectric material of the present invention, the polymeric additive may be selected from at least one of the following groups:

Homopolymers of Butadiene

Where y=70%, x+z=30%;

Random copolymers of butadiene and styrene






Wherein y=30%, x+z=70%, w=≧1, styrene content is 25 wt%;

Maleinized Polybutadiene








Wherein y=28%, x+z=72%, maleic anhydride (MA) content=8 wt%;

a copolymer of butadiene, styrene and divinylbenzene; and

Styrene Maleic Anhydride copolymer





Where X=1~8, n≧1.

In a preferred embodiment, the present invention may further selectively add a crosslinking agent to further increase the crosslinking density of the resin, and the crosslinking agent may be selected from at least one of the following groups of 40 to 80 parts by weight:

Triallyl isocyanate (TAIC)

Triallyl cyanate (TAC)

4-tert-butylstyrene (TBS)





The present invention can add an appropriate amount of a 10-hour half-life, a temperature range of 116 ° C ~ 128 ° C peroxide as a catalyst or called cross-linking accelerator, used to effectively bond the cross-linking agent with its kind of resin. Suitable peroxides for the present invention, such as dicumyl peroxide, α,α'-bis(tert-butylperoxy)diisopropylbenzene and 2,5-dimethyl-2,5-bis(tert-butyl) Peroxy)hexyne-3.

In the present invention, an inorganic filler may be further added to increase the thermal conductivity of the dielectric material, improve the thermal expansion property, and mechanical strength. Suitable inorganic fillers for the present invention are, for example, molten cerium oxide, spherical cerium oxide, talc, and aluminum silicate.

In order to improve the flame retardancy of the low dielectric material of the present invention, a halogen-based flame retardant or a non-halogen flame retardant may be added to the present invention. The halogen-based flame retardant contains, for example, decabromodiphenylethane. The non-halogen flame retardant includes, for example, a phosphorus-containing flame retardant or a phosphate ester produced by ALBEMARLE. Phosphates such as compounds having the following formula:

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The above and other objects, features and advantages of the present invention will become more <RTIgt;

The following Examples 4-1 to 4-7 were used to produce a prepreg in a continuous process using the thermosetting composition of the present invention. Glass fiber cloth is usually used as the substrate. The rolled glass fiber cloth is continuously passed through a series of rollers into a glue tank containing the thermosetting composition of the present invention. In the glue tank, the glass fiber cloth is fully wetted by the resin, and then the excess resin is scraped off by the metering roller, and then baked in the gluing oven for a certain period of time, the solvent is evaporated and the resin is solidified to a certain extent, cooled, wound, and formed into a prepreg. .

A certain number of electronic grade 2116 glass fiber cloth immersed in the prepreg made of the above resin is superimposed and aligned, and each layer is provided with a loz electrolytic copper foil in a vacuum press at a pressure of 40-900 psi and a temperature of 30 minutes. It was raised from 80 ° C to 200 ° C, then hot pressed at 200 ° C for 120 min, and then cooled to room temperature in 30 min to prepare a double-sided copper clad laminate of a certain thickness. Typically, 4 sheets of 2116 prepreg are required for a 1.0 mm thickness, 4 2116 prepregs for a 0.8 mm, and 10 21160 prepregs for a 2.0 mm.

The invention provides a thermosetting resin composition to form a stable homogeneous solution in a low boiling point solvent, and a copper clad plate manufactured therefrom, with reference to IPC-TM-650, carries out glass transition temperature, thermal decomposition temperature, thermal delamination time, solder heat resistance (288 ° C), thermal expansion coefficient, water absorption, thermal conductivity, dielectric constant and dielectric loss factor, flame resistance index detection, test results show: high glass transition temperature (Tg), excellent dielectric properties, low expansion coefficient Low water absorption, high thermal shock resistance and high thermal conductivity are suitable for substrate materials for electronic components and integrated circuit (IC) packages.

(Example)
4-1 Influence of PPE ratio difference





Comparing the relationship between Tg and Dk, Df and PPE, if the PPE amount is too high or too low, the Tg will be too low, and the amount of PPE will also affect Dk and Df. When the amount of PPE is high, Dk and Df are both high. When the amount of PPE is low, both Dk and Df are low. In the preferred situation, both Dk and Df are low. In addition, the addition of PPE will increase the coefficient of thermal expansion, so the coefficient of thermal expansion is reduced by adding BMI. The PPE model SA9000 in the table is produced by Sabic. The chemical name is poly 2,6-dimethyl-1,4-phenylene ether, or PPO (Polyphenylene Oxide) or PPE (Polypheylene ether), also known as polyphenylene. Oxide or polyphenylene ether.

4-2 Effect of BMI resin structure and ratio difference








The relationship between the coefficient of thermal expansion and the use of BMI is compared. The higher the ratio of BMI, the lower the coefficient of thermal expansion. The comparison of BMI in this embodiment can be divided into three parts, A1~A5 are different proportions of the same kind of BMI resin, A6-A8 is the same proportion but different kinds of BMI, and A9-A15 is a comparison of mixed BMI. The BMI models 2300, 4000, 5100, and TMH in the table are produced by Daiwaasei Industry CO., LTD. The chemical names are as follows.

From the perspective of A1~A5, different ratios of the same type of BMI can effectively reduce the coefficient of thermal expansion, but the water absorption rate can also be improved. From the point of view of A6-A8, different BMI can effectively reduce the coefficient of thermal expansion, but it also has an effect on the water absorption rate. From the perspective of A9-A15, different BMI combinations can also effectively reduce the coefficient of thermal expansion, and also take into account the water absorption rate. The purpose of adding BMI in the present invention is to lower the coefficient of thermal expansion. However, since the water absorption rate is also increased depending on the ratio and combination of BMI, the addition of a polymer additive is used to reduce the water absorption rate.

4-3 Effect of Structural Differences in Polymer Additives





The proportional relationship between the water absorption ratio and the polymer additive is to use polybutadiene (Polybutadiene) and styrene-maleic anhydride copolymer (SMA). When using the same polybutadiene. The higher the ratio, the lower the water absorption rate, but the coefficient of thermal expansion will also increase. When using different kinds of polybutadiene and using with SMA, it can be seen that SMA is more effective in reducing water absorption and lowering the coefficient of thermal expansion, but it is poor in Df, but it can be compensated by using polybutadiene. The lack of SMA in the Df part. The butadiene models Ricon 100, Ricon 130 MA8, Ricon 150, and Ricon 257 are produced by Sartomer, and the chemical names are as follows.

The SMA in the table lists S: M = 3: 1 is the ratio of Styrene to Maleic Anhydride, which is generally in the range of 1:1 to 12:1.

4-4 Effect of Differences in Crosslinking Types

The low dielectric material of the present invention further comprises 40 to 80 parts by weight of at least one crosslinking agent selected from the group consisting of triallyl cyanate, triallyl isocyanate, and 4-tert-butylstyrene. Comparing the influence of different crosslinking agents on the physical properties of the present invention, the Tg of the triallyl cyanate (TAC) has a poor thermal expansion coefficient, and the Dk, Df and water absorption are generally. The physical properties of those using triallyl isocyanate (TAIC) are more average. The thermal expansion coefficient, water absorption and Df of 4-tert-butylstyrene (TBS) are preferred, but the Dk value is low.

4-5 Effect of differences in types of flame retardants

The part of the flame retardant can be matched with different flame retardants depending on the physical requirements. The part containing halogen flame retardant can be added with 7~15 phr (decibromodiphenyl ethane calculated by the sum of PPE, BMI, polymer additive and crosslinker), and the part of halogen-free flame retardant can be added 12 ~14 phr (calculated as the sum of PPE, BMI, polymer additive and crosslinker) selected from at least one of the following groups: phosphorus-containing flame retardants and phosphate esters produced by ALBEMARLE (resorcinol double [two (2,6-dimethylphenyl) phosphate (Tetrakis (2,6-dimethylphenyl) 1,3-phenylene bisphosphate)).

4-6 Influence of differences in types and proportions of inorganic fillers

As for the inorganic filler, depending on the physical properties, 8 to 50 phr (calculated as the total of PPE, BMI, polymer additive and crosslinker) may be added, such as molten cerium oxide or spherical cerium oxide. In the case of the same proportion of molten cerium oxide or spherical cerium oxide, those using spherical cerium oxide have lower Dk and Df than those using molten cerium oxide.

4-7 Effect of differences in types and ratios of cross-linking accelerators

The low dielectric material of the present invention further comprises a peroxide having a 10-hour half-life temperature range of 116 ° C to 128 ° C of 2 to 8 phr (calculated as the sum of PPE, BMI, polymer additive and crosslinker). Part of the cross-linking accelerator (catalysts), depending on the physical requirements, can be combined with different cross-linking accelerators. The present invention can use a peroxide having a 10-hour half-life and a temperature range of 116 ° C to 128 ° C, preferably a peroxide having a 10-hour half-life and a temperature of 119 ° C.

The low dielectric material of the present invention uses PPE but does not add epoxy resin, because the addition of epoxy resin may cause Dk/Df to fail to reach the expected value, because the epoxy resin will generate excessive OH groups after ring opening, thereby causing Dk and The Df value cannot be lowered.

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Claims (11)

A low dielectric material comprising:
(A) 40 to 80 parts by weight of polyphenylene ether, number average molecular weight (Mn) = 1000 ~ 4000, weight average molecular weight (Mw) = 1000 ~ 7000, and Mw / Mn = 1.0 ~ 1.8;
(B) 5 to 30 parts by weight of bismaleimide (BMI);
(C) 5 to 30 parts by weight of a polymer additive,
Wherein, the Dk value of the low dielectric material is 3.75~4.0, and the Df value is 0.0025~0.0045. For example, in the low dielectric material of claim 1, wherein the polyphenylene ether has the following structural formula:





Y is at least one carbon, at least one oxygen, at least one benzene ring or a combination of the above. The low dielectric material of claim 1, wherein the bismaleimide is selected from at least one of the following groups:
Phenylmethane maleimide


Where n≧1;
Bisphenol A diphenyl ether bismaleimide


3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylethane bismaleimide
(3,3'-dimethyl-5,5'-diethyl-4,4'- diphenylethane bismaleimide)


1,6-Bismaleimide-(2,2,4-trimethyl)hexane (1,6-bismaleimide-(2,2,4-trimethyl)hexane)

The low dielectric material of claim 1, wherein the polymer additive is selected from at least one of the following groups:
Homopolymers of Butadiene


Where y=70%, x+z=30%;

Random copolymers of butadiene and styrene


Where y=30%, x+z=70%, w=≧1, styrene content=25 wt%;

Maleinized Polybutadiene


Wherein y=28%, x+z=72%, maleic anhydride content=8 wt%;
a copolymer of butadiene, styrene and divinylbenzene; and a styrene-maleic anhydride copolymer (Styrene Maleic Anhydride copolymer)


Where X=1~8, n≧1. The low dielectric material of claim 1 further comprises 40 to 80 parts by weight of at least one crosslinking agent selected from the group consisting of:
TAIC



TAC



4-tert-butylstyrene (TBS)

For example, the low dielectric material of claim 1 includes a peroxide having a 10-hour half-life temperature range of 116 ° C to 128 ° C of 2 to 8 phr (calculated as the sum of PPE, BMI, polymer additive and crosslinker). The low dielectric material of claim 6, wherein the peroxide is selected from the group consisting of at least one crosslinking accelerator: dicumyl peroxide, α, α'-double (t-butyl) Oxy)diisopropylbenzene and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3. For example, the low dielectric material of claim 1 of the patent scope further comprises 8 to 50 phr (calculated as the sum of PPE, BMI, polymer additive and crosslinker) selected from at least one inorganic filler in the following group: molten dioxide Barium, spherical cerium oxide, talc and aluminum silicate. For example, the low dielectric material of claim 1 includes 10-15 phr of decabromodiphenylethane (calculated as the sum of PPE, BMI, polymer additive and crosslinker). For example, the low dielectric material of claim 1 of the patent scope further comprises 12 to 14 phr (calculated as the sum of PPE, BMI, polymer additive and crosslinker) selected from at least one of the following groups: a phosphorus-containing flame retardant and Phosphate (resorcinol bis[bis(2,6-dimethylphenyl)phosphate]]. The low dielectric material of claim 1, wherein the low dielectric material does not contain an epoxy resin.