Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-10-02
2004-05-04
Mullis, Jeffrey (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S071000, C525S075000, C525S080000, C525S087000, C525S093000, C525S097000, C525S210000, C525S216000
Reexamination Certificate
active
06730736
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an alicyclic structure-containing resin composition, and more particularly to an alicyclic structure-containing resin composition which is excellent in heat resistance, moisture resistance, low water absorption property, dielectric properties, adhesion property, moldability, etc., markedly improved in resistance to solvent cracking and resistance to cracking in both pressure cooker test and thermal cycle test, and suitable for use as an insulating material for electronic parts.
BACKGROUND ART
In the field of electronics mounting techniques, various kinds of resin materials are used as insulating materials such as adhesives, insulating films and sealing materials. Such resin materials are often used in the form of varnishes, sheets or the like. More specifically, these resin materials are often used as film-forming materials in electronic parts making use of thin films or thick films. In the sealing of electronic parts with resins, an injection-molding method may be adopted.
Resin materials used as insulating materials for electronic parts are required to have various properties in addition to being excellent in heat resistance, dielectric properties, etc.
First, the resin materials are required to have excellent adhesion property to other materials. A coating film obtained by coating a substrate with a varnish and drying it, a sheet laminated on a substrate or between substrates, or a resin-sealed portion is required to have excellent adhesion property to substrates, semiconductor parts and the like, and high reliability. The substrates include silicon wafer substrates, ceramic substrates, glass epoxy substrates, film substrates, etc. Besides, those obtained by forming a plating film such as copper plating, or a metal wiring on a substrate are also included. Therefore, the resin materials are also required to be excellent in adhesion property to not only these various substrates, but also plating layers and metal wirings (circuit boards).
Second, electronic parts are required to sufficiently withstand reliability tests such as pressure cooker test (PCT) and thermal cycle test (TCT), in which a severe stress is applied to a specimen, in order to reduce a failure rate and elongate a life. Therefore, the thin film, thick film or resin-sealed portion formed of a resin is required not to cause cracking in these reliability tests. When cracking occurs in the resin film or the like, the insulating performance of the electronic parts is deteriorated. In addition, the electronic parts are broken down due to the penetration of water or moisture through cracks. Further, the adhesion property of the resin film or resin-sealed portion to another material such as a semiconductor part or substrate is impaired by the occurrence of cracking.
Third, the resin materials are required to have excellent resistance to solvent cracking. When a thin film, thick film or resin-sealed portion formed of a resin material is cracked by bringing it into contact with an organic solvent, the insulating performance of such an electronic part is impaired, and moreover difficulty is encountered on the fabrication of a multi-layer board using a film-forming technique. For example, when a varnish comes into contact with an underlying resin film, and the resin film is cracked by an organic solvent component contained in the varnish, the adhesion property, insulating property and the like of the resin film are impaired, and so difficulty is encountered on the formation of a multi-layer structure by, for example, using varnishes to alternately form wiring boards and insulating resin layers.
Thermosetting resins and ultraviolet-curable resins having heretofore been used in this technical field have involved such problems that they generally have no repairing property, and any property of the heat resistance, adhesion property, moisture resistance and the like is insufficient. Many of thermoplastic resins are insufficient in adhesion property and hence difficult to satisfy reliability tests under high-temperature and high-humidity conditions.
On the other hand, alicyclic structure-containing resins such as thermoplastic norbornene resins are resin materials excellent in heat resistance, moisture resistance, low water absorption property, dielectric properties (low dielectric constant and low dielectric loss tangent), moldability and the like, and are hence used as molding materials in wide fields such as an optical field, and a medical and chemical field. If these alicyclic structure-containing resins can be applied to insulating material for electronic parts, it is expected that these various properties can be sufficiently exhibited.
However, the alicyclic structure-containing resins have involved problems that when they are used as insulating materials for electronic parts, such as adhesive materials, insulating films and sealing materials in, for example, adhesion-junction of semiconductor chips to a wiring board, sealing and insulation of electronic parts, adhesion between boards (substrates), interlayer insulation, etc., they become poor in resistance to solvent cracking, and moreover insufficient in the reliability in PCT and TCT and also in adhesion property to other materials such as substrates and plating layers.
Japanese Patent Application Laid-Open No. 148347/1993 has heretofore proposed a graft-modified thermoplastic norbornene resin obtained by graft-reacting an addition copolymer of a norbornene monomer and ethylene with an amino group-containing, ethylenically unsaturated compound. Since a polar group (amino group) is introduced into this graft-modified thermoplastic norbornene resin, the resin has been improved in the adhesion property to other materials, but insufficient in long-term reliability in PCT and TCT and resistance to solvent cracking when it is used as an insulating material for electronic-parts.
On the other hand, in order to improve mechanical properties of alicyclic structure-containing resins, such as impact resistance, there has been proposed a technique that a soft polymer such as rubber is incorporated therein. For example, (1) Japanese Patent No. 2653707 has proposed resin compositions with nylon or ethylene-propylene rubber (EPR) incorporated in a maleic anhydride-modified thermoplastic norbornene resin obtained by modifying an addition copolymer of tetracyclododecene and ethylene with maleic anhydride. The maleic anhydride-modified thermoplastic norbornene resins specifically shown in this document are resins that the modification rate with maleic anhydride is as low as about 0.6 mol % based on the whole repeating unit in the copolymer. These resin compositions are provided as molded products by injection molding. (2) Japanese Patent Application Laid-Open No. 72558/1991 discloses resin compositions with styrene rubber such as styrene-butadiene copolymer rubber incorporated into a thermoplastic norbornene resin obtained by hydrogenating a ring-opening polymer of a norbornene monomer having an ester group. These thermoplastic saturated norbornene resins have an ester group in all repeating units of the polymer.
The resin compositions disclosed in these documents (1) and (2) are all improved in mechanical properties such as impact resistance by incorporating a soft polymer such as rubber into a thermoplastic norbornene resin, and are suitable for use in the formation of various kinds of molded products by injection molding and the like. These molded products are good in impact resistance and hence have a nature that they are hard to be destroyed when external force is applied thereto.
However, these conventional alicyclic structure-containing resin compositions have been not always suitable for use as insulating materials for electronic parts. More specifically, the resin compositions described in the document (1) are insufficient in resistance to solvent cracking, and resistance to cracking in TCT due to the low rate of introduction of the polar group (maleic anhydride group) though they are excellent in moisture resistance and low wat
Iga Takashi
Kaita Shojiro
Tsunogae Yasuo
Wakizaka Yasuhiro
Dinsmore & Shohl LLP
Mullis Jeffrey
Nippon Zeon Co. Ltd.
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