Teijin Limited

Amkor Electronics, Inc.

Fuji Machinery Mfg. & Electronics Co., Ltd.

Tadashi Hirakawa

Makoto Yoshida

Robert C Marrs

Kunio Nishimura

Shoji Makino

Tsukasa Kobayashi

Hirosuke Watanabe

Hiroyuki Moriga

Tamio Yamamoto

Mamoru Tsumoto

Akira Kimura

Shunzo Mitsui

Junzo Handa

Masumi Okumura

High density bonding pads in a printed circuit board for mounting a semiconductor chip are provided using a simple structure and at a low cost, while minimizing the difference in levels of bonding pads. A printed circuit board for mounting semiconductor chip(s) includes conductive traces on both sides of a base material, the first traces on a first surface of the base material having first bonding pads, the second traces on a second opposite surface of the base material having the second bonding pads. The bonding pads are located in rows adjacent each other with the base material having openings leading to the second bonding pads, such that chip bonding wires are connectible from the chip directly to the first bonding pads and through the openings to the second bonding pads.

Printed circuit board with opposed bonding shelves for semiconductor

An area grid array package such as a ball grid array enables high pin count and high density with no problems of routing, and at low cost. Independent and non-connected circuits are formed on a first surface and a second surface of an insulative base material, each circuit on each surface having first chip connection pads formed on one end to connect to a semiconductor chip, the other end having second solder ball pads to mount solder balls. The chip is connected to the first connection pads by either bonding wires or connection bumps extending through holes in the base material and are molded by a resin. Each solder ball pad on each surface has a solder ball attached with the solder balls extending through openings in the base material. The insulative base material and the semiconductor chip may be attached to a heat slug.

Ball grid array semiconductor package with solder ball openings in an

An integrated circuit package, and a method for forming the integrated circuit package, including a single layer or multilayer substrate in which interconnection vias are formed is described. Laser energy is swept across a surface of a mask in which holes have been formed. Laser energy passing through the holes of the mask forms vias in a substrate held in place below the mask. The laser energy is swept at such a speed and is maintained at such an energy level that the laser energy forms vias in the substrate, but does not penetrate a set of leads attached to the substrate. Vias may be formed in this way by either a mask imaging, contact mask or conformal mask technique. The laser energy is emitted from a non-thermal (e.g., excimer) laser. The substrate is formed of an organic (e.g., epoxy) resin. The resin may include reinforcing fibers (e.g., aramid fibers). Substrates may be formed on one or both sides of the set of leads. After formation in the substrate, the vias are coated with an electrically conductive material. The method of via formation is fast, inexpensive, achieves higher via density, and avoids overheating of the substrate.

Integrated circuit package with via interconnections formed in a

An epoxy resin-impregnated prepreg useful for the production of a copper foil-laminated board of a chip-on-board having a high heat resistance, high dimension stability and high silver migration-preventing property, comprises an aromatic polyamide fiber base material having 3.0% by weight or less of an equilibrium moisture content, 80 ppm or less of an extracted chlorine content and 50 ppm or less of an extracted sodium content, and an epoxy resin composition comprising an epoxy resin and a curing agent, containing 5 ppm or less of sodium and 600 ppm or less of chlorine and impregnated in the base material, said aromatic polyamide fibers having been produced by a wet spin-drawing process having a draw-washing procedure in which undrawn aromatic polyamide filaments are drawn at a draw ratio of 1.05 to 1.5, while forwarding the filaments through a hot water bath having a path length of 1 to 50 m and while flowing hot water at 30.degree. C. to 100.degree. C. through the bath in a counter direction against the forwarding direction of the filaments to effectively squeeze out impurities from the filaments.

Epoxy resin-impregnated prepreg

Method for forming an integrated circuit package with via interconnection

A ball grid array is formed by mounting and electrically connecting one or more electronic devices to a substrate in which vias are formed to interconnect electrically conductive traces formed in a surface of the substrate to solder ball pads formed at an opposite surface of the substrate. The vias are formed by mechanical or laser drilling. Solder balls are formed on each of the pads and are reflow-attached to, for instance, a printed circuit board. The electronic components can include one or more integrated circuit chips, as well as passive components. The electronic components are attached to the substrate using wirebonding, TAB or flip chip connection. An encapsulating material is applied to encapsulate the electronic devices.

Ball grid array with via interconnection

A surface-modified wholly aromatic polyamide fiber having an enhanced bonding property, surface tenacity and durability and a reduced friction, comprises a fiber matrix of a wholly aromatic polyamide material, fine particles of a cation-exchanging inorganic material distributed on and in a surface portion of the matrix and an additive comprising a cationic organic compound or a multi-functional organic silicone compounds, and attached to the fine organic particles.

Surface-modified wholly aromatic polyamide fiber and method of producing

A base material for a honeycomb core structure comprises a paper-like polyester fiber sheet comprising 20% to 80% by weight of drawn polyester staple fibers which preferably have a flat cross-sectional profile having a flatness, which refers to a ratio in length of a major axis to a minor axis of the profile, of from 2.5 to 30.0, 20% to 80% by weight of the sum of undrawn polyester staple fibers and other polyester staple fibers having a lower melting point than that of the undrawn polyester fibers, and having a porosity of 60% or less and a resistance to permeation of air of 100 sec/100 ml or more.

Base material for honeycomb core structure and process for producing the

A dust-proof fabric having an excellent dust-collecting efficiency and dust-preventing property including a plurality of filament yarns having a thickness of 20 to 400 denier and consisting of a plurality of individual filaments having a denier of 3.5 or less. The fabric has a number of pores formed therein and exhibits an air permeability of 0.3 to 10 ml/cm.sup.2 /sec. In the fabric, the proportion of the integrated volume of pores having a size of 43 .mu.m or more to the entire integrated volume of all the pores in the fabric is 40% or less.

Dust-proof fabric

Synthetic polyester pulps are provided which are comprised of substantially fibrous fibrils made of a linear aromatic polyester, said fibrils (i) having branches at least in part thereof, (ii) being of an oriented crystalline structure, (iii) having cross-sectional shapes that have irregular and unusual contours, and (iv) exhibiting a freeness of from 50 to 700 cc. The fibrils preferably possess an average fiber diameter of smaller than about 10 microns and a fiber diameter variance of not larger than about 0.7. The pulps are prepared by a process, which comprises the steps of: forming a shaped article from a mixture of a linear aromatic polyester and an organic compound which is incompatible with said polyester and soluble in an alkaline solution; treating the shaped article with an alkaline solution so that the polyester ingredient in the shaped article be at least partially hydrolyzed and the organic compound be at least partially dissolved in the alkaline solution; and then, beating the alkaline solution-treated shaped article.

Synthetic polyester pulp and process for preparing same

A process for producing paper or wet non-woven fabric comprising mixing an aqueous anionic polymer solution with an aqueous cationic polymer solution, adding the mixture to a slurry of fiber or pulp, converting the slurry into paper or non-woven fabric by a wet papermaking technique, and drying the paper or non-woven fabric. The paper or non-woven fabric advantageously has an excellent strength, water resistance, and thermal resistance.

Process for producing paper or non-woven fabric

A paper-like polyester sheet having an enhanced filtering property, an excellent mechanical strength and satisfactory touch and appearance, comprises polyester staple fibers and has a coefficient of air flow resistance of 1,000 to 50,000 dyn.s/cm.sup.4 at a volume fraction of the fibers of from 0.01 to 0.24.

Paper-like polyester fiber sheet and process for producing the same

A fabric filter having a low pressure drop, a high collection efficiency and an excellent cleanability is produced by raising one surface of a woven or knitted fabric comprising thermoplastic polymer fibers, to form a fibril layer containing therein the thermoplastic polymer fibrils, bringing the fibril layer into contact with a heating medium to form networks of fuse- bonded thermoplastic polymer fibrils on the fibril layer surface, and optionally, calendering the fabric.

Raised and fused fabric filter and process for producing the same

An antistatic composite yarn is obtained by wrapping a core yarn with a covering yarn. The core yarn has an electrically conductive coating thereon which comprises a polymeric matrix and a finely divided electrically conductive material therein. The antistatic composite yarn and a pile yarn are used to produce a tufted antistatic carpet. Polyamide fiber is preferably used as the covering yarn and the pile yarn. The covering yarn contains at least 40% by weight of polyamide fiber, whose content of amino end group is at least 1.0.times.10.sup.-5 mol/g higher than that of polyamide fiber contained in the pile yarn. In the case the pile yarn is composed of at least two kinds of polyamide fibers which differ from one another in the content of amino end group, one of the polyamide fibers has the content of amino end group at least 1.0.times.10.sup.-5 mol/g lower than that of another.

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Osaka, Japan

Tadashi Hirakawa