摘要:
The adhesion of chromium-copper layer to polyimide has been greatly improved by a method which provides controlled reduction, rather than total elimination, of water content in the polyimide. The electronic packaging device which incorporates the flexible circuit prepared by the method exhibits greatly improved reliability. It is believed that the invention can be used to improve the adhesion between other organic materials having moisture affinity and materials comprising in-organics or between two organic materials.
摘要:
A method for attaching adherent metal components, particularly a copper film, on at least one surface of a polyimide substrate is provided. The method comprises the steps of: exposing at least one surface of the polyimide substrate to a reactive gas plasma that provides a level of ion bombardment of the polyimide surface sufficient to disrupt at least a portion of the imide groups on the surface and to form reactive carboxylate groups, carbonyl groups and other carbon-oxygen functional groups on the surface; and then depositing a metal film onto the chemically-modified surface without intervening exposure to air. The present invention also provides a copper-coated polyimide product comprising a polyimide substrate having a substantially smooth and chemically-modified surface and a copper film directly attached to the surface, i.e., the product is free of a polymeric adhesive layer or tie coat between the surface of the polyimide substrate and the copper film.
摘要:
A method for attaching adherent metal components, particularly a copper film, on at least one surface of a polyimide substrate is provided. The method comprises the steps of: exposing at least one surface of the polyimide substrate to a reactive gas plasma that provides a level of ion bombardment of the polyimide surface sufficient to disrupt at least a portion of the imide groups on the surface and to form reactive carboxylate groups, carbonyl groups and other carbon-oxygen functional groups on the surface; and then depositing a metal film onto the chemically-modified surface without intervening exposure to air. The present invention also provides a copper-coated polyimide product comprising a polyimide substrate having a substantially smooth and chemically-modified surface and a copper film directly attached to the surface, i.e., the product is free of a polymeric adhesive layer or tie coat between the surface of the polyimide substrate and the copper film.
摘要:
A method for bonding heat sinks to packaged electronic components comprises the steps of: (a) exposing to a plasma a surface of a molded polymer formed on a substrate; (b) allowing the plasma to at least partially convert silicon-containing residue on the surface to silica; and (c) bonding an article to the surface by applying an adherent between the article and the surface. Often, the silicon-containing residue is silicone oil, a mold release compound, which may prevent the formation of a bond when using conventional bonding methods and materials. The silica layer formed on the surface of the molded polymer assists in formation of a proper bond. The plasma may be an oxygen plasma and the adherent may be selected from either a heat cured silicone-based paste adhesive with a metal oxide filler or a heat cured porous polymer film impregnated with adhesive. In particular, the film may be polytetrafluoroethylene, the adhesive may be polybutadine, and the film may be further impregnated with a metal oxide heat transfer medium, such as zinc oxide. An alternate method comprises applying the porous polymer film without plasma treatment and heat curing the film to form a proper bond.
摘要:
A metal alloy solder ball comprising a first metal and a second metal, the first metal having a sputtering yield greater than the second metal. The solder ball comprises a bulk portion having a bulk ratio of the first metal to the second metal, an outer surface, and a surface gradient having a depth and a gradient ratio of the first metal to the second metal that is less than the bulk ratio. The gradient ratio increases along the surface gradient depth from a minimum at the outer surface. The solder ball may be formed by the process of exposing the ball to energized ions of a sputtering gas for an effective amount of time to form the surface gradient.
摘要:
A semiconductor printed circuit board assembly (PCBA) and method for making same for use in electronic packages having a core layer of copper-invar-copper (CIC) with a layer of dielectric substrate placed on the core layer. A second layer of dielectric substrate is placed on the lower surface of the core layer of CIC. The layers are laminated together. Blind vias are laser drilled into the layers of dielectric substrate. The partially completed PCBA is subjected to a reactive ion etch (RIE) plasma as a first step to clean blind vias in the PCBA. After the plasma etch, an acidic etchant liquid solution is used on the blind vias. Pre-plating cleaning of blind vias removes a majority of oxides from the blind vias. Seed copper layers are then applied to the PCBA, followed by a layer of copper plating that can be etched to meet the requirements of the PCBA.
摘要:
A method of treating a conductive layer to assure enhanced adhesion of the layer to selected dielectric layers used to form a circuitized substrate. The conductive layer includes at least one surface with the appropriate roughness to enable such adhesion and also good signal passage if the layer is used as a signal layer. The method is extendible to the formation of such substrates, including to the formation of multilayered substrates having many conductive and dielectric layers. Such substrates may include one or more electrical components (e.g., semiconductor chips) mounted thereon and may also be mounted themselves onto other substrates.
摘要:
A method for bonding heat sinks to packaged electronic components comprises the steps of: (a) exposing to a plasma a surface of a molded polymer formed on a substrate; (b) allowing the plasma to at least partially convert silicon-containing residue on the surface to silica; and (c) bonding an article to the surface by applying an adherent between the article and the surface. Often, the silicon-containing residue is silicone oil, a mold release compound, which may prevent the formation of a bond when using conventional bonding methods and materials. The silica layer formed on the surface of the molded polymer assists in formation of a proper bond. The plasma may be an oxygen plasma and the adherent may be selected from either a heat cured silicone-based paste adhesive with a metal oxide filler or a heat cured porous polymer film impregnated with adhesive. In particular, the film may be polytetrafluoroethylene, the adhesive may be polybutadine, and the film may be further impregnated with a metal oxide heat transfer medium, such as zinc oxide. An alternate method comprises applying the porous polymer film without plasma treatment and heat curing the film to form a proper bond.
摘要:
A method for bonding heat sinks to packaged electronic components comprises the steps of: (a) exposing to a plasma a surface of a molded polymer formed on a substrate; (b) allowing the plasma to at least partially convert silicon-containing residue on the surface to silica; and (c) bonding an article to the surface by applying an adherent between the article and the surface. Often, the silicon-containing residue is silicone oil, a mold release compound, which may prevent the formation of a bond when using conventional bonding methods and materials. The silica layer formed on the surface of the molded polymer assists in formation of a proper bond. The plasma may be an oxygen plasma and the adherent may be selected from either a heat cured silicone-based paste adhesive with a metal oxide filler or a heat cured porous polymer film impregnated with adhesive. In particular, the film may be polytetrafluoroethylene, the adhesive may be polybutadine, and the film may be further impregnated with a metal oxide heat transfer medium, such as zinc oxide. An alternate method comprises applying the porous polymer film without plasma treatment and heat curing the film to form a proper bond.
摘要:
A method for forming a flip-chip-on-board assembly. An integrated circuit (IC) chip having a polyimide passivation layer is joined to a chip carrier via a plurality of solder bumps which electrically connect a plurality of contact pads on the IC chip to corresponding contacts on the chip carrier. A space is formed between a surface of the passivation layer and a surface of the chip carrier. A plasma is applied, to chemically modify the surface of the chip carrier and the passivation layer of the IC chip substantially without roughening the surface of the passivation layer. The plasma is either an O2 plasma or a microwave-generated Ar and N2O plasma. An underfill encapsulant material is applied to fill the space. The plasma treatment may be performed after the step of joining. Then, the chip and chip carrier are treated with the plasma simultaneously. Alternatively, the IC chip and chip carrier may be treated with the plasma before they are joined to one another. The plasma treatment improves adhesion between the encapsulant and the IC chip, and between the encapsulant and the chip carrier.