Showing papers on "Copper plating published in 1993"

Process for forming copper interconnect structure

Abstract: A copper metallization structure and process for the formation of electrical interconnections fabricated with pure copper metal is provided. The metallization structure includes an interface layer (22) intermediate to a dielectric layer (12), and a copper interconnect (30). The interface layer (22) functions to adhere the copper interconnect (30) to a device substrate (10) and to prevent the diffusion of copper into underlying dielectric layers. The interconnect layer (22) is fabricated by depositing a first titanium layer (16) followed by the sequential deposition of a titanium nitride layer (18), and a second titanium layer (20). A copper layer (24) is deposited to overlie the second titanium layer (20) and an annealing step is carried out to form a copper-titanium intermetallic layer (26). The titanium nitride layer (18) functions as a diffusion barrier preventing the diffusion of copper into the underlying dielectric layer (12), and the copper titanium intermetallic layer (26) provides an adhesive material, which adheres the copper layer (24) to the device substrate ( 10). Following the formation of the intermetallic layer (26), the device surface is planarized to form a planar surface (28), and to form an inlaid copper interconnect (30).

Printed wiring board and manufacturing method therefor

Abstract: A metal cored printed wiring board and a manufacturing method therefor, in which an organic non-conductive layer will not separate from the metal core even in an environment of high temperature and high humidity since both the metal core and the organic non-conductive layer are firmly adhered. An organic non-conductive layer is formed over the metal core (e.g., of aluminum) with a metal plated layer (e.g., nickel) therebetween for protecting the metal core. A metal oxide layer is also used for enhancing adhesive force. By utilizing such a metal oxide layer, it is possible to more effectively prevent the organic non-conductive layer from separating from the plated layer (and thus the metal core). Further, the protecting metal plated layer can protect the metal core from erosion caused by contact with a strong alkali solution, etc. as may be used in a process of forming the metal oxide layer. Still further, copper plating inside the through hole can be performed easily.

Copper foil for printed circuits and process for producing the same

Abstract: A copper foil for printed circuits has a roughened layer formed on the side of the foil to be bonded to a base, the roughened layer consisting of a number of protuberant copper electrodeposits containing chromium tungsten or both. It may also have a copper plating layer covering the roughened layer and a treatment layer covering the copper plating layer and formed of either a metal selected from the group consisting of copper, chromium, nickel, iron, cobalt, and zinc, or an alloy of two or more such metals. When necessary, the copper foil may contain an anticorrosive layer including various chromate treated layers further formed on the treatment layer. The copper foil is produced by electrolyzing a raw foil as a cathode in an acidic copper electrolytic bath at a current density close to the critical density, thereby forming the roughened layer, the electrolytic bath containing 0.001-5 g/l of chromium ion tungsten ion or both. The roughened layer is electrolytically overcoated with the treatment layer following the formation of a copper plating layer, which, when necessary, is anti-corrosively treated.

Electroless plating of copper at a low pH level

Abstract: A new process for electroless copper plating at a pH level of ≤9 is described. The process uses amine borane reducing agents and ligands based on neutral tetradentate nitrogen donors. The use of a variety of buffer systems is demonstrated. Electroless bath performance over a wide range of conditions is presented. The quality of the plated copper is comparable to that obtained by currently used electroless plating processes, and has a resistivity of about 1.8-2 µΩ-cm, depending on bath composition and process parameters. Use of the process is illustrated for forming conductors and filling via holes having submicron minimum dimensions.

Fabrication of electronic devices by electroless plating of copper onto a metal silicide

Abstract: It has been found that selective metallization in integrated circuits is expeditiously achieved through a copper plating procedure. In this process, palladium silicide is used as a catalytic surface and an electroless plating bath is employed to introduce copper plating only in regions where the silicide is present. Use of this procedure yields superior filling of vias and windows with excellent conductivity.

Circuit system, a composite material for use therein, and a method of making the material

Abstract: A circuit system has a semiconductor device mounted on a substrate which includes a composite metal material comprising a plurality of discrete elements of ferrous metal material such as an alloy of 36 percent nickel and the balance iron having a relatively low coefficient of thermal expansion, the discrete elements being copper-coated by electroless copper plating or the like and being pressed together and heated for sintering or diffusion-bonding the copper coatings together to form a continuous copper matrix having the discrete elements secured in dispersed relation therein for providing the composite metal material with a coefficient of thermal expansion relatively much lower than that of the copper material, the heating of the coated particles for diffusion bonding thereof being regulated for forming the continuous copper matrix while leaving the copper material of the matrix substantially free of nickel, ferrous or other constituents diffused therein from the discrete elements for providing the composite material with improved thermal conductivity.

Process for producing electrical circuits with precision surface features

Abstract: A process for producing fine pitch surface features on a multilayer printed circuit boards such as copper-polyimide interconnects without requiring a thick copper plating foil. Initially, a thin first conductor (less than 1 micron) is vacuum deposited on a dielectric base and the dielectric base is disposed on a substrate. The substrate is then laminated and through-holes are formed therethrough. A plating seed is deposited in the through-holes and resist is patterned on the first conductor. A second conductor is deposited on the exposed portions of the first conductor and on the sidewalls, the resist is stripped and the portions or the first conductor beneath the resist are removed using a brief wet chemical etch to form spaced features without significant undercut. In the preferred embodiment, vacuum deposition occurs in a continuous roll sputtering system.

Electroless plating solution and plating method with it

Abstract: An electroless plating solution comprises nickel ion, a chelating agent for nickel ion, dimethylamine borane, one or more soluble salts of a condensate of an arylsulfonic acid with formalin, and thiodiglycolic acid, and an electroless plating method comprises the step of immersing a substrate to be plated in this electroless plating solution for sufficent time period to form a nickel or nickel alloy layer on the substrate. The electroless plating solution has a high bath stability and is capable of forming an excellent thick deposit free from pits and cracks.

Electroless plated aramid surfaces and a process for making such surfaces

Abstract: A process is disclosed for making metal plated PPD-T fibers wherein the plating is durable and highly conductive.

Process for producing a strong bond between copper layes and ceramic

Abstract: Process for producing a strong bond between copper layers and ceramic The invention relates to a process for producing a strong bond between copper layers, which have been applied by means of thermal spraying of pulverulent copper or copper alloys, and ceramic. Fine copper powder having a mean particle diameter of ~ 20 µm is applied to the ceramic surface by means of thermal spraying.

Process for selectively depositing copper aluminum alloy onto a substrate

Abstract: An improved method is provided for depositing a thin copper aluminum alloy film on a patterned silicon substrate A copper base layer conforming to the existing pattern is initially formed on the surface of the substrate, followed by contact with vapors of an aminealane compound, which causes aluminum to be selectively deposited on the copper base layer portion of the substrate Preferably, copper is applied to a diffusion barrier surface such as tungsten using chemical vapor deposition from a complex of copper (I) perfluoroalkyl-β-diketonate and an olefin or silylolefin The entire process of developing an alloy film can be carried out without exceeding 200°C

Plating rate improvement for electroless silver and gold plating

Abstract: An electroless silver or gold plating solution comprising a noncyanide metal complex, a thiosulfate, a sulfite, and at least one amino acid. These electroless plating solutions containing an amino acid exhibit an accelerated plating rate compared to identical solutions lacking amino acids.

Multilayer wiring board

Abstract: PURPOSE:To acquire an economical multilayer wiring board of good wiring density by providing one or more insulating layers made of glass cloth reinforced resin whose linear expansion coefficient in X and Y directions is specified. CONSTITUTION:A surface copper foil of glass cloth/epoxy resin double-sided copper clad lamination boards 2a whose linear expansion coefficient in X and Y directions is 13ppm/ deg.C or less is processed by an existing etching method and an inner layer conductor circuit layer 1 is formed. Then, an epoxy resin film which does not include glass cloth and a copper foil are laminated in a surface thereof as an insulation layer 2b which becomes an outermost layer and made multilayer by press lamination at specified temperature and pressure. After a through hole is shaped by a drill and a through-hole 3 is formed by applying copper plating 4 to an inside of the hole, an outerlayer conductor circuit layer 1 is formed by an existing etching method and a multilayer wiring board is acquired. Since an insulation layer 2a whose linear expansion coefficient is 13ppm/ deg.C or less is used in the wiring board, linear expansion coefficient of an entire of the wiring board can be controlled at a specified amount or less.

Acid electrolyte solution and process for the electrodeposition of copper-rich alloys exploiting the phenomenon of underpotential deposition

Abstract: An acidic electrolytic solution for use in the electrodeposition of copper-rich alloys on a substrate, the less noble component being incorporated by underpotential deposition. The solution includes a first salt containing copper cations; a second salt containing cations of a metal less noble than copper; and an acid electrolyte (e.g., methane sulfonic acid) such that at typical current densities the potential is in the range of underpotential deposition of the less noble metal on the copper. Also provided is a process for using the acidic electrolytic solution. The process includes the following steps: (1) selecting a copper-rich alloy having, as the minor component, a metal that is less noble than copper and can form an underpotential deposition layer on copper; (2) selecting an acid electrolyte such that at typical current densities the potential is in the range of underpotential deposition of the metal on the copper; (3) providing in the acid solution simple salts of copper and of the less noble metal; and 4) applying a current between a cathode and an anode placed in the plating solution to plate the alloy on the cathode.

Dependence of selectivity on the preparation method of copper/α-alumina catalysts in the dehydrogenation of cyclohexanol

Abstract: An electroless copper plating method, a precipitation method and an impregnation method were used in the preparation of eleven Cu/α-Al 2 O 3 catalysts. The effects of the method of preparation on the dehydrogenation reaction of cyclohexanol were investigated. The results showed that the dehydrogenation activity increased as the copper loading increased up to a certain limit and then declined with further copper loading. The selectivity to cyclohexanone also increased as copper loading increased up to a certain limit, then decreased as copper loading increased for the catalyst prepared by the impregnation method. For the catalysts prepared by the electroless method the selectivity remained aemost the same. For the precipitation method the selectivity was very poor. The activation energy was lowest for ELE-3, intermediate for IMG-2 and highest for PRE-2. According to our findings, the catalysts prepared by the electroless method are better than those prepared by the other two methods, and the catalyst ELE-3 is the best one among the eleven catalysts tested.

Copper/copper alloy and graphite fiber composite and method

Abstract: A method for producing a composite having graphite fibers in a matrix of copper/copper alloy. The graphite fibers are coated with a refractory metal which both protects the graphite fibers from the molten copper/copper alloy while also acting as a wetting agent on the graphite fibers for intimate infiltration by the molten copper/copper alloy. The coated graphite fibers are prepared in a structure and placed against a copper/copper alloy element which is melted to produce the molten copper/copper alloy. The infiltration of the graphite fiber structure with the molten copper/copper alloy is characterized by the absence of pressure on the molten copper/copper alloy.

Surface treated steel strip with minimal plating defects and method for making

Abstract: In connection with a process of implementing galvanizing and galvannealing on steel strips containing highly oxidizable elements such as Si, Mn, P, Ti, Nb, Al, Ni, Cu, Mo, V, Cr, and B, after annealing in a continuous line or implementing electroplating after annealing, the present invention provides a method for restraining non-plating at low cost in a stable manner and a surface treated steel strip having minimal non-plating. By applying on at least one surface of a steel strip a Fe plating having a coating weight of 0.1-10 g/m 2 and an oxygen content of 0.1-10 wt %, followed by annealing and then zinc or zinc alloy plating, there is obtained a surface treated steel strip having minimal plating defects which includes a Fe plating layer immediately below a zinc or zinc alloy plating layer and a steel alloying element concentrated stratum immediately below the Fe plating layer. The Fe plating may be formed using an electroplating bath which contains 0.1-10 g/l of Fe 3+ and a carboxylic acid or an alkali metal salt thereof.

Copper foil for printed circuits

Abstract: There is provided a copper foil for printed circuits characterized by having a coating layer which contains zinc and zinc oxide, chromium oxide and nickel, and either or both of zinc and zinc oxide at least on the shiny side of a copper foil. The coating layer is formed by electroplating using a plating solution which contains either or both of zinc salt and zinc oxide, chromic salt and nickel salt. This copper foil resists discoloration upon exposure to high-temperature conditions of 180° C. for 30 minutes. Resist adhesion is also good. The amounts of deposits are preferably 60 to 80 μg Zn, 30 to 40 μg Cr and 5 to 20 μg Ni per dm2. The matt side of the copper foil may be treated to form thereon a single metal layer or alloy layer of one or more metals chosen from among Cu, Cr, Ni, Fe, Co, and Zn. The copper foil is suited for the fabrication of printed circuits with fine circuit patterns.

Printed wiring board and manufacture thereof

Abstract: PURPOSE:To provide a printed wiring board wherein the upside of a copper plating layer which forms a conductor pattern and the underside of an interlayer insulating layer are excellent in adhesion between them CONSTITUTION:Resin interlayer insulating layers (I1 to I5) and conductor patterns (C2 to C6) are alternately laminated on a board to form a printed wiring board, wherein a metal adhesion layer (L4) is provided between the undersides of the interlayer insulating layers (I1 to I5) and the upside of the copper plating layer (L3) which forms the conductor patterns (C2 to C6), and the metal adhesion layer (L4) is formed of at least an element selected out from nickel, chromium, molybdenum, titanium, and tungsten

Evaluation of tin plating systems for a high-noble alloy.

Abstract: The tensile bond strength of Panavia EX to a high-noble alloy prepared by abrasive spraying and tin plating was measured. Two different intraoperatory tin plating systems were compared. Disk-shaped specimens were cast in type III gold, abrasive sprayed with aluminum oxide, and divided into three groups of 30 specimens each. Specimens in one group were tin plated by using a Kura Ace Mini unit, those in the second group were tin plated by using a Micro Tin unit, and those in the third group were not tin plated and served as the control group. Disks within each group were luted to each other with Panavia EX. The specimens were thermocycled and tested in tension. There was no significant difference between the two tin plated groups; however, the luting bond of both experimental groups was significantly stronger than was that of the control (P < .05).

Mechanistic insights into metal-mediated electroless copper plating employing hypophosphite as a reducing agent

Abstract: Electroless copper plating using systems containing a small amount of Ni2+ or Pd2+ as a mediator and hypophosphite as a reducing agent was investigated using several electrochemical techniques Isothermal and component-dependent polarization, rate, Emix, split-cell, and ac impedance data suggested that the systems obey mixed potential theory and function as follows: a) the mediator is initially deposited from solution to the surface of the workpiece via hypophosphite reduction, b) oxidation of the hypophosphite at mediator sites supplies charge for Cu reduction, and c) Cu plating occurs over the entire workpiece XPS analysis and depth profiling of the resulting deposits suggested that they are homogeneous in nature and that the mediator is uniformly distributed throughout The chemical composition determined by the XPS analysis agrees well with the results obtained by atomic emission spectroscopy In addition, the analysis showed no evidence of Cu oxide formation

Electroless silver plating composition

Abstract: An electroless silver plating solution comprises a silver(I) complex, a thiosulfate salt, and a sulfite salt. This electroless silver plating solution uses a novel reducing agent combination of thiosulfate and sulfite. It shows a plating rate and a plating solution stability far superior to those of conventional silver plating solutions containing formaldehyde, reducing sugars, borohydride, hydrazine, and other reducing agents.

Methods for joining copper or its alloys

Abstract: The copper or its alloys can be bonded to each other or can be bonded to noble metals or to other metals whose surface is covered with a noble metal thin film in an oxidative atmosphere. The surface of the copper or its alloys to be bonded should be covered with the layer of a noble metal thin film or a metal oxide remover or a conductive paste mainly consisting of a copper or copper alloy particles and the metal oxide remover. This method can be applied to a metallurgical industry and also to an electronics industry. This method is especially suitable for the production of a multilayered printed wiring board.

Multilayer printed circuit board and manufacture thereof

Abstract: PURPOSE:To manufacture a multilayer printed circuit board having excellent heat cycle resistance characteristics by forming a roughed layer of a layer containing eutectic compound made of Cu, Ni and P. CONSTITUTION:Since the strength of eutectic compound itself made of Cu, Ni and P for constituting a roughed layer 2 of eutectic plating is high and the compound is of acicular crystal, the layer 2 has an excellent anchoring effect to bring a conductor circuit 7 into rigid contact with an layer insulating layer 3, and therefore the delamination due to thermal shock scarcely occurs, and heat cycle characteristics are improved. Further, since the layer 2 by eutectic plating is formed of Cu-Ni-P eutectic compound having higher chemical resistance. oxidation resistance, it is not dissolved in a chemical copper plating bath, and can obtain a high contact strength. After a surface of the circuit 7 is roughed, the layer 3 is provided on the board, a recess for a viahole is formed, a circuit is further provided by electroless plating thereby to obtain a multilayer printed board.

Fabrication of thin-film multilayer substrate using copper clad polyimide sheets

Abstract: A novel fabrication process is proposed for thin film multilayer substrates. The feature of the process involves the lamination of polyimide sheets with previously inspected wiring patterns. Several technical points were investigated during development of the process. Fairly large dimensional changes occur in the polyimide sheets in the copper etching and lamination steps. However, these changes can be restrained by fixing the sheets to rigid frames. Excimer laser ablation is a useful method to form blind via holes with a high aspect ratio. These holes can be metallized successfully by electroless copper plating. >

Diffusion of copper into gold plating

Abstract: The value of the room-temperature copper-gold interdiffusion coefficient derived by extrapolating from high-temperature measurements is an underestimate by several orders of magnitude. Plating copper with a gold film has several disadvantages. Two specimens were analyzed by using Auger electron spectroscopy. Once the full thickness of the gold film is penetrated, copper accumulates on the surface, and a layer of high concentration of copper exists immediately below the gold-air interface. Electrical resistivity of an alloy is much higher than the resistivity of either component. This high-resistivity layer may be localized within the skin depth of propagating electromagnetic waves; in cases where copper has reached the surface, it is permanently within the skin depth at any frequency. A nickel diffusion barrier, commonly applied between copper and gold, is unsuitable in many microwave and millimeter-wave applications because of ferromagnetism of nickel at room temperature. The compound that forms on the surface of untreated copper at room temperature in a reasonably clean atmosphere is cuprous oxide. Its properties make it a better alternative to gold in microwave and millimeter-wave engineering. >

Effect of the Type of Substrates on the Ductility and Microstructure of Electroless Copper Deposits

Abstract: The ductility of fine-grained (0.1∼0.5 μm) electroless copper deposits was found to vary with the type of substrates that they were plated on; under identical plating conditions, the ductility of the electroless copper grown on activated plastic substrates was higher than that grown epitaxially on a large-grained copper foil. This ductility difference is shown to originate from a difference in the void structure developed at the grain boundaries of the deposits during film formation

Process for the production of substrate for printed wiring

Abstract: The process comprises the production of a substrate for printed wiring, which has high thickness accuracy and permits the formation of a printed wiring network by most general methods such as wet electroless copper plating without impairing the excellent properties of an inorganic continuous porous material such as a low coefficient of thermal expansion, high heat dissipation properties and high machinability, the process comprising wrapping a thick plate-like inorganic continuous porous material (I) with a cloth or paper (IV), impregnating the wrapped inorganic continuous porous material (I) with a thermosetting resin (II) under reduced pressure, curing the thermosetting resin to form a composite material(III), and slicing the composite material (III) into substrates having a predetermined thickness.

Method for concurrent production of copper powder and a metal chloride

Abstract: A novel method is proposed for concurrently producing a metallic copper powder and a valuable chloride of a metal other than copper, e.g., manganese, zinc, cobalt, nickel and tin, from a depleted aqueous etching solution containing copper (II) chloride as discharged from the etching process in the manufacture of copper-foiled printed circuit boards. The inventive method also contributes to solve the problem for the disposal of such a waste solution without causing the troubles in connection with environmental pollution. The inventive method comprises the steps of: treating the waste solution with an active carbon so as to remove organic impurities; admixing the solution with a powder, granules or flakes of the above mentioned metal so as to precipitate the copper value in the metallic form, instead, giving an aqueous solution of the chloride of the added metal; and separating the copper metal powder and the chloride solution.