Stock material or miscellaneous articles – Structurally defined web or sheet – Physical dimension specified
Reexamination Certificate
2000-01-04
2004-12-21
Jackson, Monique R. (Department: 1773)
Stock material or miscellaneous articles
Structurally defined web or sheet
Physical dimension specified
C428S320200, C428S323000, C428S327000, C428S328000, C428S414000, C428S416000, C428S457000, C428S461000, C428S462000, C428S500000, C428S521000, C156S306600, C156S306900, C156S311000, C156S327000
Reexamination Certificate
active
06833180
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an adhesive for semiconductor parts, and more particularly to an adhesive for semiconductor parts, which comprises a cyclic structure-containing thermoplastic polymer as a base polymer and has excellent shelf stability, adhesive property, heat resistance, moisture resistance, low water absorption property, dielectric properties (low dielectric constant and dielectric loss tangent), productivity, mechanical properties and long-term reliability. The present invention also relates to a production process of a semiconductor part package, comprising the step of bonding a semiconductor part to a wiring board (substrate) with such an adhesive. The present invention further relates to a semiconductor part package bonded with such an adhesive.
BACKGROUND ART
With the rapid advancement of advanced information-oriented society in recent years, there is a strong demand for the enhancement of throughput capacity of information processing apparatus such as computers and communication apparatus, i.e., the speeding up. In addition, their miniaturization and weight saving are required so as to be portable.
Of these requirements, in order to achieve the speeding up of the information processing, it is effective to make the interconnected wiring of passive parts and active parts such as LSI, memory and so as short as possible so as to make wiring density high in packaging of semiconductor parts mounted in an apparatus. This technique is also effective for the miniaturization and weight saving of information processing apparatus.
As a means for shortening the distance of the interconnected wiring, there is bare chip mounting in which semiconductor chips are directly mounted on a substrate. In particular, flip chip bonding (FC) in which an electrode of a semiconductor chip (semiconductor integrated circuit device) and an electrode of a wiring board are directly bonded to each other through bumps (fine metal projections; for example, Au bumps or solder bumps) is the most effective process.
In the flip chip bonding, metallurgical bonding making good use of a metallic material such as an Sn—Pb solder has been mainly used. More specifically, when a semiconductor chip is mounted on a wiring board, the semiconductor chip is placed on a conductive pattern of the wiring board to conduct solder bonding. In the soldering process, it is necessary to conduct flow soldering subsequently to reflow soldering. Therefore, the process is complicated, and any part poor in heat resistance cannot be mounted. In addition, since joints in the adhesion or bonding of semiconductor parts are increasingly made small, the processing by the solder bonding becomes difficult.
In order to meet requirements such as high-density packaging and miniaturization of electronic apparatus, enhancement of electrical performance, reduction in production cost and automization of packaging, various surface mounting techniques including non-metallurgical bonding have therefore been developed. For example, a method, in which bumps are formed on a semiconductor chip, an insulating resin layer is formed on a wiring board, and both semiconductor chip and wiring board are headed and press-bonded to each other, thereby directly bonding an electrode of the semiconductor chip to an electrode of the wiring board in a shortest distance through bumps, is put to practical use. The insulating resin layer is generally formed by a thermosetting resin having adhesive property, such as an epoxy resin, and so adhesion between the semiconductor chip and the wiring board by the setting of the resin is conducted at the same time as the bonding between the electrodes.
Besides, a method, in which bumps are formed on a semiconductor chip, an anisotropic conductive film is interposed in a space between the semiconductor chip and a conductive pattern on a wiring board, and both chip and board are pressed against each other, thereby press-bonding the bumps of the semiconductor chip to the conductive pattern on the wiring board to form electrical connection, has been developed. The anisotropic conductive layer is generally formed by an anisotropic conductive material obtained by dispersing a conductive filler such as metallic fine particles or resin balls (fine particles), on the surfaces of which a conductive film has been provided, in a binder resin. In the bonding mechanism making use of the anisotropic conductive material, the conductive filler dispersed in the anisotropic conductive material is present on connection terminals with a certain probability, and the conductive filler is squeezed from point contact to a state close to face contact by applying heat and pressure upon bonding, thereby giving conductivity and at the same time fully bonding the chip to the wiring board to achieve stable bonding. If the filling amount of the conductive filler is too great, interterminal leakage and lowering of adhesive force are incurred. If the amount is too small on the other hand, a problem arises on connection resistance. More specifically, lateral insulation property and conductivity between upper and lower terminals are balanced by controlling the amount of the conductive filler dispersed. In addition, the adhesive force is controlled.
The non-metallurgical bonding using the insulating resin or anisotropic conductive material has a merit that the bonding can be conducted at a relatively low temperature compared with the solder bonding. According to the packaging by the non-metallurgical bonding, the limitation of materials to be bonded is relaxed compared with the solder bonding, and application range thereof is widened. The requirement of heat resistance to the parts and boards (substrates) can also be relaxed due to bonding at a lower temperature, and moreover packaging cost can be reduced because washing-out of flux is unnecessary.
In the non-metallurgical bonding, thermosetting resins and ultraviolet-curing resins have heretofore been commonly used as the insulating resins or binder resins from the viewpoints of adhesive property and heat resistance. However, the bonding using the thermosetting resin or ultraviolet-curing resin has involved a problem of repairability against bonding failure occurred in a packaging process. More specifically, it is extremely difficult to repair a defective unit when such a resin is cured by heating and pressing (pressurizing) or irradiation of ultraviolet light upon bonding. Even if a semiconductor chip can be separated from a wiring board, it is difficult to remove residue of the cured resin. In the case of a semiconductor package, to scrap the whole package due to a partial defect results in a great loss of cost. Accordingly, there is a demand for establishing techniques such as repair of wiring, and exchange and reuse of semiconductor chips.
In these application fields, thermosetting epoxy resins (adhesives) have heretofore been particularly preferably used because variations of its connection resistance value under high-temperature conditions are little. The epoxy resins are roughly divided into one-pack type that a main material is mixed with a hardener in advance, and two-pack type that a main material is mixed with a hardener upon use. However, in the case of the one-pack type epoxy resins in which the main material is mixed with the hardener in advance, most of them must be stored under refrigeration in order to prevent the reaction of the main material with the hardener before use. Since the one-pack type epoxy resins are cured at a low temperature, their pot life at room temperature is at most about 1 day. Even when they are stored under refrigeration, the pot life is about 2 to 3 months. In addition, their workability is poor because the temperature must be returned to room temperature upon use. Further, the one-pack type epoxy resins involve a problem that they take up moisture when the temperature is returned to room temperature to deteriorate their properties.
On the other hand, in the case where that the two-pack type epoxy resins in which the main material is mixed with
Dinsmore & Shohl LLP
Jackson Monique R.
Nippon Zeon Company, Ltd.
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