Motorola Corporation

Fadia Nounou

Robert W Pennisi

James L Davis

Anthony B Suppelsa

Bobby Dean Landreth

Anthony J Suppelsa

Robert J Mulligan

William B Mullen, Iii

Frank J Juskey, Jr

Kingshuk Banerji

A method of making a transfer molded chip carrier. A semiconductor device (10) is first electrically and mechanically attached to a substrate (12). The substrate (12) is then treated by sputter etching so that it will provide good adhesion between the substrate and a molding compound (18) that is subsequently molded to the substrate (25). Portions of the treated substrate are then selectively contaminated in order to reduce the adhesion between these selected portions of the substrate and the molding compound. The molding compound is then formed around the semiconductor device so as to encapsulate it and also part of the surface of the substrate. Portions (20) of the transfer molded material that were molded over the selectively contaminated portions of the substrate (12) are then removed by breaking away.

Method of selectively releasing plastic molding material from a surface

A method of manufacturing a circuit carrying substrate having one or more coaxial via holes. The center core or inner layer (330) of the circuit carrying substrate is a dielectric material that has a plated (339) through hole or via (335) coupling the two surfaces of the inner layer together. One side of the inner layer has a first metallization pattern (336) and the other side has a second metallization pattern (338) on it. The through hole is electrically conductive (339) and connects portions of the first and second metallization patterns. The plated through hole is filled with a dielectric material (340). A first dielectric layer (342) is formed on one side of the inner layer, and a second dielectric layer (344) is formed on the other side of the inner layer, so that the dielectric layers cover the first and second metallization patterns and the filled via hole. A third metallization pattern (350) is formed on the first dielectric layer, and a fourth metallization pattern (360) is formed on the second dielectric layer. A second via hole (370) is formed within the first via hole, substantially concentric to and electrically insulated from the first via hole, to electrically connect the third and fourth metallization patterns.

Method of manufacturing a circuit carrying substrate having coaxial via

A self centering coil (200) includes a coil section (202) and also having curved end section (206) and (204) at opposite sides of the coil section (202). The curved end sections are preferably substantially flat and in a plane which is parallel to the center axis (306) of the coiled section (202).

Self centering coil

A semiconductor device package comprises a substrate (20) having a metallization pattern (22) on at least one surface, and a semiconductor device (10) having an active surface (12) and a grounded surface (14) on opposed sides. The semiconductor device is electrically attached to the substrate metallization pattern with the active surface (12) facing the substrate. A polymeric underfill material (30) substantially fills the space between the semiconductor device and the substrate. An electrically conductive material (35) covers the exposed grounded surface (14) of the semiconductor device and at least a portion of the metallization pattern (22), providing electrical connection between the grounded surface of the semiconductor and the metallization pattern (22) on the substrate.

Backplane grounding for flip-chip integrated circuit

Solder pastes having vehicles including formic acid-soluble organic acids as fluxing agents are described. Fluxing agents may be compounds of the formula: ##STR1## where R is an electron withdrawing group. In one embodiment, R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. Other suitable formic-acid fluxing agents include, but are not limited to, adipic acid, acrylic acid, polyacrylic acid, methacrylic acid and polymethacrylic acid. The compounds clean oxides from the printed circuit boards (PCBs) under assembly and then volatilize leaving a residue to be cleaned away. The cleaning step involves rinsing with formic acid. No undesired residue remains indicating that the organic acids of the invention are effective in cleaning boards. Such acid fluxing agents can be used mixed with typical solder components, such as lead/tin solder pastes, or applied topically to solders, such as solder balls; both techniques permit the assembly of PCBs more easily with high quality bonds, and with little or no residue. Malic acid is a preferred organic acid fluxing agent. The formic acid cleaning step may be followed by a water rinse.

Method of cleaning printed circuit boards using formic acid

A solder paste is formulated by combining a solder paste vehicle, a resin, and solder alloy particles. The solder paste vehicle is made by combining mono and polyfunctional alcoholic solvents with a fluxing agent. The solder particles are first reacted with a formate ion produced by formic acid, formaldehyde, paraformaldehyde, or mixtures thereof, in order to create a metal-formate complex that functions as an oxygen scavenger on the surface of the solder alloy particles.

Solder paste having solder alloy/formate complexes as oxide scavengers,

Solder pastes having vehicles including blends of low boiling point alcohols and relatively high boiling point alcohols are described which leave residues which may be cleaned using only water are described. The low boiling point alcohols have a boiling point range of between about 65.degree. and about 150.degree. C. whereas the high boiling point alcohols have a boiling point in rhe range of about 150.degree. to about 270.degree. C. The solder pastes also use water-soluble organic acids as fluxing agents such as compounds of the formula: ##STR1## where R is an electron withdrawing group such as fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. Other suitable formic-acid fluxing agents include, but are not limited to, adipic acid, polyacrylic acid, methacrylic acid and polymethacrylic acid. The compounds clean oxides from the printed circuit boards (PCBs) under assembly and then volatilze leaving a residue to be cleaned away. The cleaning step involves rinsing with water. No undesired residue remains indicating that the organic acids of the invention are effective in cleaning boards. Malic acid is a preferred organic acid fluxing agent.

Method of cleaning printed circuit boards using water

Fluxing compositions are described containing as fluxing agents compounds of the formula: ##STR1## where R is an electron withdrawing group. In one embodiment, R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. The compound cleans oxides from the printed circuit boards (PCBs) under assembly and then volatilize with little or no need for a cleaning step, or cleaning only with water or formic acid. Very little or no undesired residue remains. Such acid fluxing agents can be used mixed with typical solder formulations, such as lead/tin solder pastes, or applied topically to solders, such as solder balls; both techniques permit the assembly of PCBs more easily with high quality bonds, and with little or no residue. Malic acid is a preferred organic acid fluxing agent.

Use or organic acids in low residue solder pastes

Fluxing compositions containing compounds that generate acids upon photoinitiation from a light source such as Hg/Xe ultraviolet (UV) light sources are described. The acids clean oxides from the printed circuit boards (PCBs) under assembly and then volatilize with little or no need for a cleaning step, or cleaning only with water. The compounds that release an oxide removing agent, sometimes called a 'photoacid' include metal and organic onium salts and furyl compounds bearing a carbonyl group. Such fluxing compositions can be used mixed with typical solder formulations, such as lead/tin solders, or applied topically thereto; both techniques permit the assembly of PCBs more easily and with high quality bonds.

Solder fluxes bearing oxide removers generated by light

A manifold (10) for use in a gas solder-reflow oven (50) comprises a hollow tube made from a transition metal having an open end (18) for receiving gas, a closed end (16), and a plurality of holes (12).

Gas manifold for solder reflow processing atmosphere

Solder paste vehicles using blends of monofunctional and polyfunctional alcohols are described. The blend may have a major portion of a low viscosity, monofunctional alcohol solvent and a minor portion of a high viscosity polyfunctional alcohol thickener. The monohydric solvent has a room temperature viscosity of at least 3 centipoise and from about 3 to 18 carbon atoms and may include such materials as 2-butanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-dodecanol, 2-ethoxyethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, n-hexadecanol, n-octadecanol, benzyl alcohol and mixtures thereof. The polyalcohol has a room temperature viscosity of between about 26 to about 1500 cp and includes compounds such as 1,2-ethanediol; 1,2-propanediol; 1,3-propanediol; 1,2-butanediol; 1,3-butanediol; 1,4-butanediol; 1,2-pentanediol; 1,5-pentanediol; 2,4-pentanediol; 2,5-hexane-diol; glycerol; 1,2,4-butanetriol; 2,2'-(ethylenedioxy)diethanol; 1,12-dodecane-diol; 1,16-hexanedecanediol and mixtures thereof. These blends give improved solubility of organic acid fluxing agents, provide relatively high viscosities of the solder paste and permit lower amounts of solvent to be used.

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Plantation, FL, United States of America

Fadia Nounou