Patent Publication Number: US-2017369747-A1

Title: Resin composition, adhesive film, and circuit board using the same

Description:
FIELD 
     The subject matter generally relates to a resin composition, an adhesive film using the resin composition, and a circuit board using the resin composition. 
     BACKGROUND 
     Circuit boards generally include conductive circuits and insulating layers coupling the conductive circuits. A high dielectric constant of the insulating layer may affect impedance matching of the circuit board and thus slow down a high frequency signal transmission in the circuit board. Thus, an insulating layer having a low dielectric constant is needed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
         FIG. 1  is a cross-sectional view of an exemplary embodiment of an adhesive film. 
         FIG. 2  is a cross-sectional view of a circuit board using the adhesive film of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of a test sample of the circuit board of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
     Several definitions that apply throughout this disclosure will now be presented. 
     The term “comprising” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the like. The term “about” when utilized, means “not only include the numerical value, but also includes numbers close to the numerical value.” 
     An exemplary embodiment of a resin composition comprises a styrene-butadiene-styrene block copolymer (SBS) in an amount of about 95 to about 100 parts by weight, modified porous spheres of silicon oxide in an amount of about 1 to about 50 parts by weight, and a liquid polybutadiene in an amount of about 5 to about 50 parts by weight. 
     The SBS comprises vinyl groups on its side chains. The SBS can be selected from a group consisting of an SBS obtainable from Kraton Polymers under the trade names “D1101”, “DX405”, or any combination thereof. 
     The modified porous spheres of silicon oxide are formed by processing silicon oxide to form nanoporous material and modifying the porous silicon oxide to form vinyl groups. 
     The liquid polybutadiene comprises vinyl groups on its side chains. The vinyl groups of the liquid polybutadiene are able to react with the vinyl groups of the SBS and the modified porous spheres of silicon oxide when the resin composition is heated, thereby forming a cross-linking network structure. The cross-linking structure has a higher density than a resin composition in the absence of the modified porous spheres of silicon oxide. In addition, the cross-linking network structure can prevent the modified porous spheres of silicon oxide from being agglomerated in the resin composition, thus allowing the modified porous spheres of silicon oxide to be uniformly dispersed in the resin composition. Such resin composition is also easily stored. 
     The liquid polybutadiene may be selected from a group consisting of liquid polybutadiene having vinyl groups in an amount greater than or equal to 50% by weight, and liquid maleic polybutadiene, or any combination thereof. 
     The liquid polybutadiene having vinyl groups in an amount greater than or equal to 50% by weight may be selected from a group consisting of liquid polybutadiene obtainable from Cray Valley Corporation under the trade names “Ricon 142”, “Ricon 150”, “Ricon 152”, “Ricon 153”, “Ricon 154”, “Ricon 156”, “Ricon 157”, or any combination thereof. 
     The liquid maleic polybutadiene may be selected from a group consisting of maleic polybutadiene obtainable from Cray Valley Corporation under the trade names “Ricon 130MA8”, “Ricon 130MA13”, “Ricon 130MA20”, “Ricon 142MA3”, “Ricon 184MA6”, “Ricobond 1731”, “Ricobond 2031”, “Ricobond 1756”, or any combination thereof. 
     The resin composition further comprises an additive selected from a group consisting of a flame retardant, an ion trapper, or any combination thereof. If the resin composition comprises the flame retardant, the flame retardant is in an amount of about 5 to about 250 parts by weight. If the resin composition comprises the ion trapper, the ion trapper is in an amount of about 0.5 to about 10 parts by weight. 
     The flame retardant may be phosphate compound. In at least one exemplary embodiment, the flame retardant may be selected from a group consisting of bisphenol diphenyl phosphate, ammonium polyphosphate, hydroquinone bis-(diphenyl phosphate), trimethyl phosphate (TMP), dimethyl methyl phosphonate (DMMP), resoreinol dixylenylphosphate (RDXP), melamine polyphosphate, accidentally phosphorus compounds, phosphazene compound, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), or any combination thereof. 
     The ion trapper may be selected from a group consisting of aluminum silicate, hydrated metal oxide, polyvalent metal salt, heteropoly acid, or any combination thereof. The hydrated metal oxide may be selected from a group consisting of antimony oxide hydrate (Sb 2 O 5 .2H 2 O), and bismuth oxide hydrate (Bi 2 O 3 .nH 2 O), such as an ion trapper obtainable from TOAGOSEI CO., LTD under the trade names“IEX-600”. The polyvalent metal salt may be selected from a group consisting of zirconium hydrogen phosphate monohydrate (Zr(HPO 4 ) 2 .H 2 O), titanium hydrogen phosphate monohydrate (Ti(HPO 4 ) 2 .H 2 O), or any combination thereof. The heteropoly acid may be selected from a group consisting of molybdenum ammonia phosphate hydrate ((NH 4 ) 3 Mo 12 (PO 4 ) 40 .nH 2 O), hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ), aluminum magnesium carbonate hydroxide hydrate (AlMg(OH) 3  CO 3 .nH 2 O), or any combination thereof. 
     An exemplary embodiment of a method for preparing the resin composition may comprise the following steps. 
     Step 1, the SBS in an amount of about 95 to about 100 parts by weight, the modified porous spheres of silicon oxide in an amount of about 1 to about 50 parts by weight, the liquid polybutadiene in an amount of about 5 to about 50 parts by weight, and the additive in an amount of about 0.5 to about 260 parts by weight, are all added into a container to obtain a mixture. 
     Step 2, the mixture is stirred to cause the SBS, the modified porous spheres of silicon oxide, the liquid polybutadiene, and the additive to be fully mixed. 
       FIG. 1  illustrates an embodiment of an adhesive film  100  made by the resin composition. The adhesive film  100  comprises a release film  10  and a resin layer  20  attached to at least one surface of the release film  10 . The adhesive film  100  may be made by coating the resin composition on the at least one surface of the release film  10  and then solidifying the resin composition to form the resin layer  20 . In at least one embodiment, the coated resin composition is solidified for 15 mins at 110 degrees centigrade to form the adhesive film  100 . The resin layer  20  is a semi-solidified layer. 
       FIG. 2  illustrates an embodiment of a circuit board  200  made by the resin layer  20 . The circuit board  200  comprises a circuit substrate  201  and the resin layer  20  attached on at least one surface of the circuit substrate  201 . The resin layer  20  may be attached to the circuit substrate  201  by hot-pressing. 
     When the resin composition is heated, the vinyl groups of the SBS, the modified porous spheres of silicon oxide, and the liquid polybutadiene will react with each other to form a cross-linking network structure. The cross-linking density of the resin composition is thus improved. The resin layer  20  has a better heat resistance to avoid destruction when being soldered. In addition, the cross-linking network structure causes the modified porous spheres of silicon oxide to be uniformly dispersed in the resin layer  20 . This prevents any decrease in the adhesive strength of the resin layer  20  and causes roughness of the surfaces of the resin layer  20 . When the resin layer  20  made by the resin composition and the circuit substrate  201  are pressed together, the modified porous spheres of silicon oxide being uniformly dispersed in the resin composition ensures that the adhesion strength of the resin layer  20  is uniform. 
     Example 1 
     The resin composition was made by adding SBS (Manufacturer: Kraton Polymers, Model: D1101) of 100 g, liquid maleic polybutadiene (Manufacturer: Cray Valley Corporation, Model: Ricon 184MA6) of 10 g, modified porous spheres of silicon oxide of 3.5 g, and ion trapper (Manufacturer: TOAGOSEI CO., LTD., Model: IEX-600) of 5 g into a container and stirring until the SBS, the liquid maleic polybutadiene, the modified porous spheres of silicon oxide, and the ion trapper were fully mixed. 
     Example 2 
     The resin composition was made by adding an amount of SBS (Manufacturer: Kraton Polymers, Model: DX405) of 95 g, liquid polybutadiene (Manufacturer: Cray Valley Corporation, Model: Ricon 150) of 10 g, modified porous spheres of silicon oxide of 3.5 g, and ion trapper (Manufacturer: TOAGOSEI CO., LTD., Model: IEX-600) of 5 g into a container and stirring until the SBS, the liquid polybutadiene, the modified porous spheres of silicon oxide, and the ion trapper were fully mixed. 
     Comparative Example 1 
     A composition was made by adding an amount of SBS (Manufacturer: Kraton Polymers, Model: D1101) of 100 g, liquid maleic polybutadiene (Manufacturer: Cray Valley Corporation, Model: Ricon 184MA6) of 10 g, and ion trapper (Manufacturer: TOAGOSEI CO., LTD., Model: IEX-600) of 5 g into a container and stirring until the SBS, the liquid maleic polybutadiene, and the ion trapper were fully mixed. 
     Comparative Example 2 
     A composition was made by adding an amount of SBS (Manufacturer: Kraton Polymers, Model: DX405) of 95 g, liquid polybutadiene (Manufacturer: Cray Valley Corporation, Model: Ricon 150) of 10 g, and ion trapper (Manufacturer: TOAGOSEI CO., LTD., Model: IEX-600) of 5 g into a container and stirring until the SBS, the liquid polybutadiene, and the ion trapper were fully mixed. 
     Comparative Example 3 
     A composition was made by adding an amount of SBS (Manufacturer: Kraton Polymers, Model: D1101) of 100 g, liquid maleic polybutadiene (Manufacturer: Cray Valley Corporation, Model: Ricon 184MA6) of 10 g, unmodified porous spheres of silicon oxide of 3.5 g, and ion trapper (Manufacturer: TOAGOSEI CO., LTD., Model: IEX-600) of 5 g into a container and stirring until the SBS, the liquid maleic polybutadiene, the unmodified porous spheres of silicon oxide, and the ion trapper were fully mixed. 
     Comparative Example 4 
     A composition was made by adding an amount of SBS (Manufacturer: Kraton Polymers, Model: DX405) of 95 g, liquid polybutadiene (Manufacturer: Cray Valley Corporation, Model: Ricon 150) of 10 g, unmodified porous spheres of silicon oxide of 3.5 g, and ion trapper (Manufacturer: TOAGOSEI CO., LTD., Model: IEX-600) of 5 g into a container and stirring until the SBS, the liquid polybutadiene, the unmodified porous spheres of silicon oxide, and the ion trapper were fully mixed. 
       FIG. 3  illustrates a test sample  300  made by the resin composition of the example 1. The test sample  300  comprises a copper foil  301 , a polyimide (PI) film  302 , and a resin film  303  sandwiched between the copper foil  301  and the polyimide film  302 . The resin film  303  was attached to the copper foil  301  and the polyimide film  302 . In the illustrated embodiment, the resin film  303  used for making the test sample  300  was made by the resin composition of the example 1. 
     Furthermore, five other test samples  300  were made by the above-described method using the resin compositions of the examples 2 and compositions of the comparative examples 1, 2, 3, and 4, respectively. 
     The dielectric constant and the dielectric dissipation factor of each of the resin films formed by the resin compositions made in examples 1 to 2 and the compositions made in the comparative examples 1 to 4 were tested. 
     Copper peeling strength, PI peeling strength, dispersing property of the modified porous spheres of silicon oxide, and film forming property of the resin film of the six test samples  300  were tested, and the test results were shown in Table 1. If the resin film has no precipitant at a bottom surface, the dispersing property of the modified porous spheres of silicon oxide is “good”; otherwise the dispersing property is “bad”. If the surfaces of the resin film are flat, the film forming property of the resin film is “good”; otherwise the film forming property is “bad”. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Products 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                   
                 Compar- 
                 Compar- 
                 Compar- 
                 Compar- 
               
               
                   
                   
                   
                 ative 
                 ative 
                 ative 
                 ative 
               
               
                   
                 Example 
                 Example 
                 example 
                 example 
                 example 
                 example 
               
               
                 Property 
                 1 
                 2 
                 1 
                 2 
                 3 
                 4 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Dielectric constant 
                 2.57 
                 2.45 
                 2.70 
                 2.56 
                 2.57 
                 2.46 
               
               
                 (10 GHz) 
                   
                   
                   
                   
                   
                   
               
               
                 Dielectric dissipation 
                 0.006 
                 0.007 
                 0.006 
                 0.007 
                 0.006 
                 0.007 
               
               
                 factor (10 GHz) 
                   
                   
                   
                   
                   
                   
               
               
                 Copper peeling 
                 0.98 
                 1.21 
                 1.10 
                 1.35 
                 0.59 
                 0.61 
               
               
                 strength (kgf/cm) 
                   
                   
                   
                   
                   
                   
               
               
                 PI peeling strength 
                 1.01 
                 1.13 
                 1.17 
                 1.27 
                 0.48 
                 0.42 
               
               
                 (kgf/cm) 
                   
                   
                   
                   
                   
                   
               
               
                 Dispersing property of 
                 good 
                 good 
                 — 
                 — 
                 bad 
                 bad 
               
               
                 the modified porous 
                   
                   
                   
                   
                   
                   
               
               
                 spheres of silicon oxide 
                   
                   
                   
                   
                   
                   
               
               
                 Film forming property 
                 good 
                 good 
                 good 
                 good 
                 bad 
                 bad 
               
               
                 of the resin film 
               
               
                   
               
            
           
         
       
     
     According to Table 1, the dielectric constant of the resin films made by the resin compositions of example 1 is lower than those of the resin films made by the compositions of comparative example 1, and the dielectric constant of the resin films made by the resin compositions of the example 2 is lower than those of the resin films made by the compositions of comparative example 2. In addition, the copper peeling strength and the PI peeling strength of the resin films made by the resin compositions of examples 1 and 2 are higher than those of the resin films made by the compositions of comparative examples 3 and 4. The dispersing property of the modified porous spheres of silicon oxide and the film forming property of the resin film made by the resin compositions of examples 1 and 2 are better than those of the resin films made by the compositions of comparative examples 3 and 4. 
     The embodiments shown and described above are only examples. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structures and function of the present disclosure, the disclosure is illustrative only, and changes can be made in the detail, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including, the full extent established by the broad general meaning of the terms used in the claims.