Adhesives having improved chemical resistance and curable silicone compositions for preparing the adhesives

• US 20050282959A1
• Filed: 07/14/2005
• Published: 12/22/2005
• Est. Priority Date: 08/14/2003
• Status: Active Grant

• Current Assignee: Dow Silicones Corporation (Dow, Inc.)
• Original Assignee: Dow, Inc.
• Inventors: Ahn, Dongchan, Rolley, Patricia Ann
• Granted Patent: US 7,521,125 B2
• Time in Patent Office: Days
• US Class Current: 524/861
• CPC Class Codes: C08K 5/10 Esters; Ether-esters
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C08L 83/08 containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen
• CPC Class Codes: C09J 183/04 Polysiloxanes
• CPC Class Codes: H01L 2224/32145 the bodies being stacked
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

This invention relates to a composition that can be cured to form an adhesive. The adhesive is useful in the electronics industry. The composition is prepared by mixing components including: (I) a polyorganosiloxane having an average of at least two terminally-unsaturated organic groups per molecule, (II) an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule, (III) a hydrosilylation catalyst, (IV) a fluoroorganosilicone having at least one functional group reactive with component (I), component (II), or both, (V) an unsaturated ester-functional compound, and (VI) an adhesion promoter. The composition may also include one or more optional components selected from (VII) a void reducing agent, (VIII) a pigment, (IX) a filler, (X) a cure modifier, (XI) a rheology modifier, and (XII) a spacer.

Claims

1. A method comprising:

(1) applying a composition to a substrate, and (2) curing the composition;

where the composition is prepared by mixing components comprising

(I) a polyorganosiloxane having an average of at least two unsaturated organic groups per molecule,

where component (I) is free of fluorine atoms;

(II) an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule,

where component (II) is free of fluorine atoms;

(III) a hydrosilylation catalyst;

(IV) a fluoroorganosilicone having at least one functional group reactive with component (I), component (II), or both;

(V) an unsaturated ester-functional compound; and

(VI) an adhesion promoter.

2. The method of claim 1, where the substrate comprises an epoxy, a polycarbonate, a poly(butylene terephthalate) resin, a polyamide resin, a blend of polyamide resin with syndiotactic polystyrene, an acrylonitrile-butadiene-styrene, a styrene-modified poly(phenylene oxide), a poly(phenylene sulfide), a vinyl ester, a polyphthalamide, a polyimide, silicon, aluminum, a stainless steel alloy, titanium, copper, nickel, silver, gold, or combinations thereof.

3. The method of claim 1, where the substrate comprises a metal.

4. The method of claim 1, where component (I) comprises a polyorganosiloxane of the formula:

R¹₃SiO(R¹₂SiO)_α

(R¹²SiO)_β

SiR¹₃,  

 

(a)
R³₂R⁴SiO(R³₂SiO)_χ

(R³R⁴SiO)_δ

SiR³₂R⁴, or  

 

(b)

(c) a combination thereof, where

α

has an average value of 0 to 2000,

β

has an average value of 2 to 2000,

each R¹ is independently a monovalent organic group,

each R² is independently an unsaturated monovalent organic group,

χ

has an average value of 0 to 2000,

δ

has an average value of 0 to 2000,

each R³ is independently a monovalent organic group, and

each R⁴ is independently an unsaturated monovalent organic group.

5. The method of claim 1, where component (I) comprises an MQ resin consisting essentially of R⁵₃SiO_1/2 units and SiO_4/2 units, a TD resin consisting essentially of R⁵SiO_3/2 units and R⁵₂SiO_2/2 units, an MT resin consisting essentially of R⁵₃SiO_1/2 and R⁵SiO_3/2 units, an MTD resin consisting essentially of R⁵₃SiO_1/2 units, R⁵SiO_3/2 units, and R⁵₂SiO_2/2 units, or a combination thereof, where

each R⁵ is a monovalent organic group of 1 to 20 carbon atoms, and

the resin contains an average of 3 to 30 mole percent of unsaturated organic groups.

6. The method of claim 1, where component (II) comprises siloxane units selected from HR⁶₂SiO_1/2, R⁶₃SiO_1/2, HR⁶SiO_2/2, R⁶₂SiO_2/2, R⁶SiO_4/2, or combinations thereof;

where each R⁶ is independently selected from monovalent organic groups free of aliphatic unsaturation.

7. The method of claim 1, where component (II) comprises a compound of the formula:

R⁷₃SiO(R⁷₂SiO)_ε

(R⁷HSiO)_φ

SiR⁷₃, or  

 

(a)
R⁸₂HSiO(R⁸₂SiO)_γ

R⁸HSiO)_η

SiR⁸₂H,  

 

(b)

(c) a combination thereof, where

ε

has an average value of 0 to 2000,

φ

has an average value of 2 to 2000,

each R⁷ is independently a monovalent organic group free of aliphatic unsaturation,

γ

has an average value of 0 to 2000,

η

has an average value of 0 to 2000, and

each R⁸ is independently a monovalent organic group free of aliphatic unsaturation.

8. The method of claim 1, where component (III) comprises a platinum metal, a rhodium metal, or an organometallic compound.

9. The method of claim 1, where component (IV) comprises a compound of the formula:

R⁹₃SiO(R⁹₂SiO)_τ

(R⁹R¹⁰SiO)_φ

SiR⁹₃,  

 

(a)
R¹¹₂R¹²SiO(R¹¹₂SiO)_κ

(R¹¹R¹²SiO)_λ

SiR¹¹₂R¹²,  

 

(b)
(c) F₃C(CF₂)_ν

R¹³—

Si—

[O—

Si(R¹⁴)₂(R¹⁵)]₃,  

 

(c)

(d) a resinous or branched structure consisting essentially of R¹⁵R¹⁴₂SiO_1/2 units, CF3(CF₂)_ν

R¹³SiO_3/2 units, and optionally SiO_4/2 units, or

(e) a combination thereof;

where

ξ

has an average value of 0 to 2000,

φ

has an average value of 1 to 500,

each R⁹ is independently a hydrogen atom or a monovalent organic group, with the proviso that at least one R⁹ is a hydrogen atom or an unsaturated monovalent organic group;

each R¹⁰ is independently a fluoro-functional organic group;

κ

has an average value of 0 to 2000;

λ

has an average value of 0 to 500;

each R¹¹ is independently a hydrogen atom or a monovalent organic group, with the proviso that at least one R¹¹ is a hydrogen atom or an unsaturated monovalent organic group;

each R¹² is independently a fluoro-functional organic group;

each R¹³ is independently a divalent organic group;

each R¹⁴ is independently a monovalent hydrocarbon group free of aliphatic unsaturation;

ν

is 0 to 10; and

each R¹⁵ is independently a hydrogen atom or an unsaturated monovalent organic group.

10. The method of claim 1, where component (V) comprises:

11. The method of claim 1, where component (VI) comprises a transition metal chelate, an alkoxysilane, a combination of an alkoxysilane and a hydroxy-functional polyorganosiloxane, or a combination thereof.

12. The method of claim 1, where component (VI) comprises an unsaturated alkoxysilane, an epoxy-functional alkoxysilane, an epoxy-functional siloxane, or a combination thereof.

13. The method of claim 1, where component (VI) comprises an alkoxysilane of the formula R²⁸μ

Si(OR²⁹)<sub>(4-μ

)</sub>, where

μ

is 1, 2, or 3,

each R²⁸ is independently a monovalent organic group, with the proviso that at least one R²⁸ is an unsaturated organic group or an epoxy-functional group, and

each R²⁹ is independently an unsubstituted, saturated hydrocarbon group of at least 1 carbon atom.

14. The method of claim 1, where the composition further comprises (VII) a void reducing agent, (VIII) a pigment, (IX) a filler, (X) a cure modifier, (XI) a rheology modifier, (XII) a spacer, an acid acceptor, an anti-oxidant, a stabilizer, a flame retardant, a flow control additive, a reactive diluent, an anti-settling agent, a silylating agent, a desiccant, a blowing agent, or a combination thereof.

15. The method of claim 1, where the composition has SiH_tot/Vi_tot of 1.05 to 5.0.

16. The method of claim 1, where the method forms a product selected from die attach adhesives, as lid seals, gels and encapsulants.

17. The method of claim 1, where the composition is applied to more than one substrate in step (1).

18. A method comprising:

(1) applying a composition onto a housing,

(2) placing a lid over the housing such that the edges of the lid are in contact with the composition to form an assembly, and

(3) curing the composition to form a sealed housing;

where the composition is prepared by mixing components comprising

(I) a polyorganosiloxane having an average of at least two unsaturated organic groups per molecule,

where component (I) is free of fluorine atoms;

(II) an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule,

where component (II) is free of fluorine atoms;

(III) a hydrosilylation catalyst;

(IV) a fluoroorganosilicone having at least one functional group reactive with component (I), component (II), or both;

(V) an unsaturated ester-functional compound; and

(VI) an adhesion promoter.

19. A method comprising:

(1) applying a composition over an electronic circuit board, and

(2) curing the composition to produce a sealed circuit board;

where the composition is prepared by mixing components comprising

(I) a polyorganosiloxane having an average of at least two unsaturated organic groups per molecule,

where component (I) is free of fluorine atoms;

(II) an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule,

where component (II) is free of fluorine atoms;

(III) a hydrosilylation catalyst;

(IV) a fluoroorganosilicone having at least one functional group reactive with component (I), component (II), or both;

(V) an unsaturated ester-functional compound; and

(VI) an adhesion promoter.

20. A method comprising:

(1) applying a composition on an electronic substrate,

(2) attaching a semiconductor die to the composition,

(3) curing the composition to produce a bonded composite.

optionally (4) repeating steps (1) to (3) to attach one or more additional semiconductor dice to the semiconductor die,

optionally (5) wire bonding the semiconductor die or semiconductor dice,

optionally (6) cleaning,

optionally (7) overmolding the semiconductor die or semiconductor dice with a molding compound, and

optionally (8) attaching solder balls to form a finished package;

where the composition is prepared by mixing components comprising

(I) a polyorganosiloxane having an average of at least two unsaturated organic groups per molecule,

where component (I) is free of fluorine atoms;

(II) an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule,

where component (II) is free of fluorine atoms;

(III) a hydrosilylation catalyst;

(IV) a fluoroorganosilicone having at least one functional group reactive with component (I), component (II), or both;

(V) an unsaturated ester-functional compound; and

(VI) an adhesion promoter.