Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2001-11-13
2004-06-01
Raymond, Richard L. (Department: 1624)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C526S256000, C526S262000, C544S073000, C544S090000, C544S095000
Reexamination Certificate
active
06743852
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to benzoxazines. In a particular aspect, the present invention relates to benzoxazine-containing thermosetting resin compositions. In yet another aspect, the present invention relates to compositions useful as adhesives for assembling electronic devices, as well as other applications, such as within the aerospace industry.
BACKGROUND OF THE INVENTION
Reliable performance of electronic devices depends primarily on the integrity of the microelectronic components contained therein. Most electronic devices contain several microchips which are housed in a variety of protective packages. These packages are composed of several distinct materials, each of which performs a specific function and contributes to the overall integrity of the package. For example, a typical ball-grid array (BGA) package contains, in addition to the substrate and microchip attached thereto, materials such as overmold adhesive, die-attach adhesive, and solder mask. The incorporation of all of these disparate materials into one package creates several adhesive interfaces within the package itself. In order to produce a reliable, long-lasting electronic device, the structural integrity of these interfaces must be maintained.
Interfacial adhesion is a critical parameter for the production of reliable microelectronic components. Materials with dissimilar coefficients of thermal expansion must be adhered via void-free bonds. The presence of any delamination in the final assembled product can lead to moisture entrapment within the void volume. The trapped moisture can be released “explosively” once the defective part is heated to solder reflow temperatures during final component assembly. The formation of sound adhesive bonds at the various interfaces present within a microelectronic package is therefore critical for the survival of that package during assembly. The formation of sound adhesive bonds is also necessary to insure a long service life for the final product.
Adhesive interfaces within electronic components are currently subjected to increasingly stringent processing conditions. For example, environmental concerns have resulted in a worldwide mandate to remove lead from all aspects of the microelectronic assembly process. The use of lead-free solder alloys, however, creates a new challenge for the reliable assembly of microelectronic components. The reflow temperatures required by lead-free alloys are several degrees higher than those containing lead. Soldering operations based on these new alloys generally must be conducted around 260° C., which is about forty degrees Celsius higher than had been previously required. The new, higher reflow temperatures place an extra strain on all of the adhesive interfaces within microelectronic packages. Indeed, strong adhesion at all of these interfaces is critical to the reliability of a microelectronic component.
Benzoxazines and compositions containing benzoxazines are known (see for example, U.S. Pat. Nos. 5,543,516 and 6,207,786 to Ishida, et. al.; S. Rimdusit and H. Ishida, “Development of New Class of Electronic Packaging Materials Based on Ternary Systems of Benzoxazine, Epoxy, and Phenolic Resins”,
Polymer,
41, 7941-49 (2000); and H. Kimura, et. al., “New Thermosetting Resin from Bisphenol A-based Benzoxazine and Bisoxazoline”,
J. App. Polym. Sci.,
72, 1551-58 (1999)). However, benzoxazines have generally not been used as components of thermosetting resin compositions to increase the interfacial adhesion thereof.
Accordingly, there is a need for compositions and methods which increase interfacial adhesion within microelectronic components.
SUMMARY OF THE INVENTION
In accordance with the present invention, there are provided novel benzoxazine compounds and thermosetting resin compositions prepared therefrom. Invention compositions are particularly useful for increasing adhesion at interfaces within microelectronic packages. Invention benzoxazines are useful for the preparation of invention compositions with properties which are associated with increased adhesion at interfaces, such as, for example, low shrinkage on cure and low coefficient of thermal expansion (CTE).
In another aspect of the invention, there are provided die-attach pastes having increased interfacial adhesion. Invention die-attach pastes include benzoxazine-containing thermosetting resin compositions.
In further aspects of the invention, there are provided methods for enhancing adhesive strength of thermosetting resin compositions and methods for enhancing adhesion of a substrate bound to a metallic surface by a thermosetting resin composition.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, there are provided benzoxazines having the following structure:
wherein:
L is an optional alkylene or siloxane linking moiety,
Ar is optionally substituted arylene,
Q is an oxazine ring or amine salt thereof having the structure:
and is bonded to Ar in a fused manner at positions 5 and 6 of the oxazine ring, wherein:
Sp is optional, and if present, is an optionally substituted C
1
to C
6
alkylene, oxyalkylene, thioalkylene, carboxyalkylene, amidoalkylene, or sulfonatoalkylene spacer,
n is 1 or 2,
m is optional, and if present, is 1 or 2,
x and y are each independently 0 to 4, and
wherein at least one of R, R′, and R″ is a polymerizable moiety.
As employed herein, “arylene” refers to aromatic groups having in the range of 6 up to 14 carbon atoms and “substituted arylene” refers to arylene groups further bearing one or more substituents selected from hydroxy, alkyl, alkoxy, mercapto, cycloalkyl, substituted cycloalkyl, heterocyclic, substituted heterocyclic, aryl, substituted aryl, heteroaryl, substituted heteroaryl, aryloxy, substituted aryloxy, halogen, cyano, nitro, nitrone, amino, amido, C(O)H, acyl, oxyacyl, carboxyl, carbamate, sulfonyl, sulfonamide, sulfuryl, and the like.
As employed herein, “alkylene” refers to divalent hydrocarbyl radicals having 1 up to 20 carbon atoms, preferably 2-10 carbon atoms, and “substituted alkylene” refers to alkylene moieties bearing one or more of the substituents as set forth above.
As employed herein, “oxyalkylene” refers to an alkylene moiety wherein one or more of the carbon atoms have been replaced by oxygen atoms, and “substituted oxyalkylene” refers to an oxyalkylene moiety further bearing one or more of the substituents as set forth above.
As employed herein, “thioalkylene” refers to an alkylene moiety wherein one or more of the carbon atoms have been replaced by sulfur atoms, and “substituted thioalkylene” refers to an thioalkylene moiety further bearing one or more of the substituents as set forth above.
As employed herein, “carboxyalkylene” refers to an alkylene moiety wherein one or more of the carbon atoms have been replaced by a carboxyl group, and “substituted carboxyalkylene” refers to a carboxyalkylene moiety further bearing one or more of the substituents as set forth above.
As employed herein, “amidoalkylene” refers to an alkylene moiety wherein one or more of the carbon atoms have been replaced by an amido group, and “substituted amidoalkylene” refers to an amidoalkylene moiety further bearing one or more of the substituents as set forth above.
As employed herein, “sulfonatoalkylene” refers to an alkylene moiety wherein one or more of the carbon atoms have been replaced by a sulfonato group, and “substituted sulfonatoalkylene” refers to a sulfonatoalkylene moiety further bearing one or more of the substituents as set forth above.
As employed herein, “polymerizable moiety” refers to any substituent that can participate in polymerization reaction, such as, for example, an addition polymerization or a condensation polymerization. As employed herein, addition polymerization refers to polymerization mechanisms such as free-radical polymerization, anionic polymerization, cationic polymerization, ring-opening polymerization, or coordinative polymerization. As employed herein, condensation polymerization refers to polymerizations such as siloxane polyme
Dershem Stephen M.
Liu Puwei
Mizori Farhad G.
Bauman Steven C.
Henkel Corporation
Raymond Richard L.
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