Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-12-05
2004-12-14
Robertson, Jeffrey B. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S212000, C523S216000, C428S391000, C428S405000, C428S447000, C428S450000
Reexamination Certificate
active
06831117
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an adhesive and, more particularly, to a hardener particle used for an adhesive by which semiconductor chip and TCP (tape carrier package) are connected to substrates by means of a thermal compression bonding.
2. Description of Related Art
Adhesives containing an epoxy resin as a thermosetting resin have been conventionally used in connecting semiconductor chips onto a substrate or in manufacturing electric apparatuses by connecting TCP to LCD (liquid crystal display).
The reference numeral
111
in
FIG. 9A
shows an LCD, and the LCD
111
has a glass substrate
112
and ITO (indium tin oxide) electrodes
113
arranged on the glass substrate
112
. In connecting the LCD
111
to a TCP which will be mentioned later, an adhesive is firstly applied on the surface of the side to which the ITO electrodes
113
of the LCD
111
are arranged. The reference numeral
125
in
FIG. 9B
shows an adhesive applied on the LCD
111
.
The reference numeral
115
in
FIG. 9C
shows a TCP, and the TCP
115
has a base film
116
and metal wirings
117
arranged on the surface of the base film
116
. The side on which the metal wirings
117
of the TCP
115
are arranged is disposed to an adhesive
125
on the LCD
111
, and after being positioned, the side to which the metal wirings
117
of the TCP
115
are arranged are arranged is pushed to the adhesive
125
.
When heated as pushed in such a state, the adhesive
125
softens, and the metal wirings
117
push away the softened adhesive
125
, thereby attaching to the surface of the ITO electrodes
113
.
A hardener such as imidazole polymerized of an epoxy resin by heating is generally added to the adhesives mentioned as above, and when heating is further continued in a state where the metal wirings
117
are attached to the ITO electrodes
113
, the epoxy resin is polymerized by a catalytic reaction of the hardener to harden the adhesive
125
.
The reference numeral
101
in
FIG. 9D
shows an electric apparatus in a state where the adhesive
125
is hardened. In the electric apparatus
101
, the TCP
115
and the LCD
111
are fixed by the hardened adhesive
125
while the metal wirings
117
are attached to the ITO electrodes
113
. Accordingly, the TCP
115
and the LCD
111
are connected to each other electrically and mechanically.
However, when the above adhesive is hardened, it is necessary to heat the adhesive at the temperature of as high as not lower than 180° C. and, if the pattern of the metal wiring
117
is fine, there may be the case where deformation such as elongation or warp is resulted in the TCP
115
upon heating. Such a problem may be solved when heating temperature is lowered but time required for the heating treatment becomes longer and productivity lowers.
With regard to adhesives having excellent hardening property at low temperature, radically polymerizable resins such as acrylate and adhesives where a radical polymerization initiator have been developed in recent years but such adhesives are inferior in electric characteristics and heat resistance in a hardened state to an adhesive using an epoxy resin.
The present invention has been created for solving the above-mentioned inconveniences in the prior art, and its object is to provide an adhesive able to be hardened under the condition of lower temperature and short time and also has excellent preserving property.
The inventor of the present invention has paid an attention to a means where commonly used hardeners are not used but an epoxy resin is subjected to a cationic polymerization and carried out the investigation repeatedly and, as a result, it has been that, when a silane compound having at least one alkoxy group in a structure (a silane coupling agent) and a metal chelate (or a metal alcoholate) are added to an adhesive, silanol where the silane coupling agent is hydrolyzed and cation where the metal chelate is reacted are produced and then the epoxy resin is polymerized by the cation.
The step of hardening of the epoxy resin by an adhesive to which metal chelate and silane coupling agent are added will be illustrated by the following reaction formulae (5) to (8).
As shown in the reaction formula (5), a silane compound having at least one alkoxy group reacts with water in the adhesive whereupon the alkoxy group is hydrolyzed to give a silanol group.
When the adhesive is heated, the silanol group reacts with metal chelate such as aluminum chelate and the silane compound is bonded to the aluminum chelate (the reaction formula (6)).
After that, as shown in the reaction formula (7), another silanol remaining in the adhesive in an equilibrium reaction is arranged to the aluminum chelate to which the silanol is bonded whereupon Bronsted acid points are produced and, as the reaction formula (8) shows, an epoxy ring located at the end of the epoxy resin is opened by the activated proton and is polymerized with an epoxy ring of another epoxy resin (cationic polymerization). As such, when a silane coupling agent and a metal chelate are added to an adhesive, a thermosetting resin such as epoxy resin is cationically polymerized. Since the reactions as shown by the reaction formulae (6) to (8) proceed at lower temperature than the temperature (180° C.) at which the conventional adhesives are hardened, the adhesive as mentioned above hardens at lower temperature within shorter time than in the case of the conventional ones.
However, a silane coupling agent is apt to be hydrolyzed and, in addition, reactivity of the silanol with a metal chelate or a metal alcoholate is high. Therefore, when a powdery metal chelate or metal alcoholate is directly dispersed to an adhesive as hardener particles, polymerization reaction of an epoxy resin proceeds even at ambient temperature and preservation property of the adhesive becomes poor.
The present inventor has carried out further intensive investigation and, as a result, it has been found that preserving property of the adhesive becomes high when a compound having hydroxyl group such as alcohol or a silane coupling agent is contacted to the surface of the hardener particles before addition of the hardener particles to an adhesive so that the compound is made to react with the central metal of the surface of the hardener particle.
SUMMARY OF THE INVENTION
The present invention has been constituted on the basis of the above-mentioned findings. A hardener particle mainly according to the invention includes either metal chelate where at least one ligand is coordinated to central metal or a metal alcoholate where at least one alkoxy group is bonded to central metal or both, wherein silicon is bonded to the central metal located on the surface of the hardener particles via oxygen.
In a preferred embodiment, the silicon is bonded to the central metal are bonded to each other via oxygen. A substituent bonded to the silicon may be represented by the following formula (1) or formula (2)
(the substituent X
1
in the above formula is bonded to the silicon),
(at least one substituent among the substituents X
2
~X
4
in the above formula (2) is bonded to the silicon)
Herein, exemplified as substituent X
1
are, e.g., —CH
2
CH
2
CH
2
—, —CH
2
CH
2
CH
2
NHCH
2
CH
2
—, —CH
2
CH
2
CH
2
NHC(═O)—. Exemplified substituents X
2
to X
4
are, e.g., phenyl group, H, —(CH
2
)
n
— (n is integer). The substituents X
2
to X
4
coupling to silicon, among them, can be, e.g., —CH
2
CH
2
CH
2
NHCH
2
CH
2
—, —CH
2
CH
2
CH
2
NHC(═O)—.
In another aspect of the invention, a hardener particle mainly includes either metal chelate where at least one ligand is coordinated to central metal or a metal alcoholate where at least one alkoxy group is coordinated to central metal or both, and the hardener particles in which carbon is bonded to the central metal located on the surface of the hardener particles via oxygen.
In further aspect of the invention, a manufacturing method for a hardener particle, includes the steps of forming silanol in hydrolyzing a silane coupling agent
Robertson Jeffrey B.
Sony Chemicals Corporation
Welsh & Katz Ltd.
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