Composition for electrochemical deposition of nickel coatings
(57) Abstract:Usage: the invention relates to electrochemistry, in particular the production of Nickel coatings with low contact resistance, for example, ohmic contacts to semiconductor materials. Essence: the existing structures was not possible to obtain ohmic electroplating from aqueous electrolytes semiconductor MnSi, FeSi, CoSi. This is achieved in that the composition contains Nickel sulfate, boric acid, sodium chloride and hydrofluoric acid in the following proportions of ingredients, g/l: Nickel sulfate with NISO47H2O 350 400; boric acid (H3BO325 35; NaCl 4,5 5,5; hydrofluoric acid HF 90 110. The invention relates to electrochemistry (electroplating), in particular the production of Nickel coatings with low contact resistance, for example, ohmic contacts to semiconductor materials.There are many compositions for the deposition of Nickel coatings on a wide range of materials, working in a variety of conditions.One of the urgent tasks of the semiconductor instrumentation is the necessity of creating semiconductor materials ohmic contacts. The floor is of high temperatures, and when normal conditions as sources of EMF to power electrical equipment; sensors radiation in a wide frequency range.Nickel, used to getting contacts is a material resistant to neutron irradiation; corrosion-resistant and heat-resistant component in the alloys, which is important for the electrochemical formation of the transition (ohmic) contact area of the semiconductor - Nickel; analogous to the structure of the outer electron shells in relation to Cr, Mn, Fe, Co, the 4th period of the periodic table of elements of D. I. Mendeleev) used for the synthesis of MnSi, CoSi, FeSi.In galvanothermy most common electrolytes on the basis of Nickel sulfate. These electrolytes are mainly used to obtain a protective and decorative coating of machine parts for corrosion protection at elevated temperatures and in special environments (alkalis and some acids).Known composition to obtain a Nickel coating on the metal, in particular iron  . The electrolyte composition contains, g/l: Nickel Sulfate with NISO47H2O 250-300 sodium Chloride NaCl 10-15 Boric acid, H3IN325-40 sodium Fluoride NaF 5-6 Formaldehyde 0,4-0,8 2,6(2,7)-Naphtha - Lin-disulpho - acid 2-4 Self the CoSi, this composition is not acceptable, as it contains a large amount of organic additives, which are captured in the process of electrolysis growing Nickel Deposit. This leads to an increase of electric resistance of the transition region of the Nickel-semiconductor (loss obecnosci).For the prototype accepted the composition of  for the deposition of Nickel coatings containing g/l: Nickel Carbonate NiCO35-15 Hydrofluoric acid HF 1-2 sodium Dihydrophosphate NaH2PO4H2O 15-20 Citric acid3H4(OH)(CO2H)35-7 sodium Hydroxide NaOH 5-10
This composition is intended for the deposition of Nickel coatings on light metal, in particular magnesium.The disadvantage of this composition is the impossibility of using it to obtain ohmic galvanic coatings on semiconductor materials, in particular on MnSi, FeSi, CoSi, working in conditions of high radiation and high temperatures ( 103OC). The unacceptability of this composition is due to the fact that it is designed for a narrow range of materials light metals, in particular magnesium and contains in its composition of ingredients in this together (NaOH, NaH2PO2H2O, CH4(OH)(CO2H)the data of the electrolyte for magnesium coatings are obtained porous and require subsequent ultrasonic machining in the electrolyte plating.The aim of the invention is to provide opportunities for ohmic galvanic Nickel coatings on semiconductors MnSi, FeSi, CoSi.The aim is achieved in that in the known structure for the electrochemical deposition of Nickel coatings including Nickel-containing compound and hydrofluoric acid according to the formula of the invention, as the Nickel compounds used Nickel sulfate, optionally, the electrolyte contains boric acid and sodium chloride is in the following ratio, g/l: Nickel Sulfate with NISO47H2O 350-400 Boric acid (H3BO325-35 NaCl 4,5-5,5 Hydrofluoric acid HF 90-110
The need to use as Nickel compounds with NISO47H2O due to the good solubility of this salt in the proposed structure, which allows to find the optimal concentration of the Nickel component in the electrolyte for a wide range of materials;
the necessity of introducing into the electrolyte H3BO3due to the fact that H3BO3- buffer additive to create a stable concentration of hydrogen ions in the electrolyte - shifts the potential of the deposition of Nickel in electrophoretically s account of Cl-, i.e., provides a stable ion concentration Ni+2due to the continuous dissolution of Nickel anodes, improves the conductivity of the electrolyte at the expense of Na+.The need to comply with the concentration limits for the ingredients in the electrolyte was determined experimentally. The change of this ratio leads to deterioration of obecnosci the transition region of the Nickel coating is a semiconductor. When going beyond the proposed concentrations necessary for the operation of a semiconductor device level obecnosci (104-106Ohm cm2) disappears.Thus, each of the features is necessary, and together they are sufficient to achieve the objectives of the invention.Not known for the claimed combination of features, though separately used ingredients known as constituent parts contained in the electrolyte composition intended for obtaining Nickel coatings. For example, in many electrolytes include Nickel compounds: with NISO47H2O; NiCO3however , being different from the claimed combination of features, they lead to non-achieved a positive effect, namely the fir coatings on semiconductors.Only through the totality of the stated characteristics, the interaction of all the components drawn in the specified proportions, was able to identify a new property that allows you to manage simultaneously reaching reactions etching (semiconductor and deposited Nickel coating) and the deposition of Nickel on semiconductors changing the current density and polarity, as well as to stimulate the processes of electrolysis semiconductor MnSi, FeSi, CoSi due to its own radiation chemical reactions going on in the volume of the electrolyte and the electrodes, which, in turn, manifested itself in a new positive effect, namely the ability to obtain ohmic galvanic coatings on semiconductors MnSi, FeSi, CoSi. Thus the claimed technical solution meets the criterion of "Significant differences".For preparation of a composition for electrochemical deposition of Nickel coatings have been used with NISO47H2O; H3BO3; NaCl; HF. Sample was taken in the ratios shown in the table, and was dissolved in water at 80aboutC. as semiconductors, which caused the Nickel coating was used fresh polycrystals MnSi, FeSi, CoSi. As a cell line which was little more than a Nickel, the cathode is a sample of a semiconductor material. The samples were immersed in the cell surface. To prevent deposition of Nickel on the other sides of the sample they previously were isolated from exposure to the electrolyte, a protective coating (e.g., Capon-Lac). The electrolysis is carried out by passing an electric current of 100 A/DM2. When conducting electrolysis within 60 C. was obtained Nickel coating thickness of 10 μm. Contact resistance at the boundary of metal - semiconductor was measured by microprobe analysis.The results are summarized in table, which shows the concentration of the components in the minimum, average and maximum values.From the above examples it is seen that in the claimed range of concentrations was able to obtain ohmic galvanic coatings on three types of semiconductors. The measured value of the contact resistance in all examples is in the range of 10-4-10-6Ohm cm2that suggests the possibility of using the obtained Nickel coatings as ohmic contacts. Outside the experimentally found ratios of the components present in this formulation the level of obecnosci below 10-4Ohm cm2that A claimed composition allows to obtain ohmic galvanic coatings on semiconductors MnSi, FeSi, CoSi , which did not provide the composition of the prototype. (56) white, M. A. , Ivanov A. F. Electrodeposition of metallic coatings, M. : 1985, S. 95.Ivanova N. D. fluoride electroplating. Kiev, 1986 S. 83.Patent Germany N 3022402, CL H 01 L 21/445, 1980. COMPOSITION FOR ELECTROCHEMICAL deposition of NICKEL COATINGS including Nickel-containing compound and hydrofluoric acid, characterized in that, in order to obtain ohmic galvanic coatings on semiconductors MnSi, FeSi, CoSi from aqueous electrolytes, as Nickel compounds using Nickel sulfate with NISO47H2O, and the electrolyte further comprises boric acid and sodium chloride is in the following ratio of ingredients, g/l:
With NISO47H2O 350 - 400
H3BO325 - 35
NaCl 4,5 - 5,5
HF 90 - 110
FIELD: micro- and nanoelectronics, micro- and nanomechanics where insulated conductors are used.
SUBSTANCE: proposed method for filling pockets in solid body with conducting material includes coating of solid-body surface, bottom, and side walls of mentioned pockets with first layer that functions as barrier material preventing diffusion of mentioned conducting material in solid body; application of second layer onto first one that functions as wetting layer for conducting material; application of third layer by way of physical or chemical deposition onto third one from gas phase that has in its composition mentioned conducting material; coating of third layer with fourth one that also incorporates conducting material; melting of conducting material by heating and profile leveling; material melting by heating is conducted after applying third layer and fourth layer is applied by any method of physical deposition from gas phase, chemical deposition from gas phase, chemical deposition from solution, electrochemical deposition, or chemical-mechanical deposition.
EFFECT: facilitated procedure, enlarged functional capabilities.
12 cl, 17 dwg
SUBSTANCE: invention is attributed to microelectronics and can be used in production of semiconductor devices and integral circuits. Essence of invention: in the method of attaching silicon chip to chip holder, chip seating surface is successively sputtered with two titan-germanium metals, and chip to chip holder soldering is carried out at temperature of 280-300°C.
EFFECT: improvement of chip with chip-holder contact reliability and stability of attachment process.
SUBSTANCE: method involves notching in bulk of a silicon wafer and silicone removing from the wafer back to uncover notch bottoms. Notching enables silicone pattern formation to represent hollow cell walls that is followed with wall-through oxidation to form a dielectric SiO2 conduit system. Silicon removing from the back of the wafer can be conducted by the deep plasma etch process.
EFFECT: high strength of the insulating element which can be used for manufacturing various MEMS devices in bulk of a standard silicon wafer.
2 cl, 13 dwg
SUBSTANCE: in manufacturing method of multi-level copper metallisation of VLSIC, which involves application operations of metal and dielectric layers, photolithography and selective etching of those layers, chemical mechanical polishing of dielectric layers, to plate of silicium, which is coated with dielectric material with vertical conductors of underlying structure, which protrude on its surface, there applied is multi-layered conducting film consisting of adhesive barrier, etched and auxiliary layers; grooves are formed in auxiliary layer before etched layers by electrochemical method; copper horizontal conductors are grown inside grooves in open sections of etched layer till grooves are fully filled; the second auxiliary layer is applied to surface of plate, and in that layer holes are made to the surface of horizontal copper conductors; vertical copper conductors are grown by electrochemical method in open sections of horizontal conductors till holes for vertical conductors are fully filled; then, auxiliary layers are removed; conducting layers between horizontal copper conductors are removed; dielectric layers are applied to surface of the plate by smoothing and filling methods, and then dielectric material layers are removed above vertical conductors by means of chemical and mechanical polishing method.
EFFECT: improving quality of copper conductors.
16 cl, 11 dwg, 1 tbl
FIELD: instrument making.
SUBSTANCE: invention relates to semiconductor devices production process, in particular to technology of making contacts with lowered resistance. In method of semiconductor device making contacts are formed on basis of platinum. For this film of platinum with thickness of 35-45 nm is applied by electron-beam evaporation on silicon substrate, heated prior to 350 °C, at rate of deposition of 5 nm/min. Then heat treated in three stages: 1 step is carried out at temperature of 200 °C for 15 minutes, 2 step is carried out at temperature of 300 °C for 10 minutes and 3 stage is at 550 °C for 15 min in forming gas, with mixture of gases N2:H2=9:1.
EFFECT: proposed method of semiconductor device making provides reduced contact resistance, high technological effectiveness, improved parameters of devices, high quality and yield.
1 cl, 1 tbl
SUBSTANCE: invention relates to the field of semiconductor production technology, namely to a technology of low-resistance silicide layers formation. The method of semiconductor devices manufacture includes formation of an amorphous layer by silicon ion implantation on the silicon plate with the energy of 50 keV and dose⋅ of 5⋅1015 cm-2, at the substrate temperature of 25°C. Prior to the palladium layer application, the substrate is sequentially etched in nitric, sulfuric and hydrofluoric acid, then washed with deionized water. The palladium layer is applied at a temperature of 25-100°C, with a thickness of 0.1 microns at a rate of 1.5 nm/sec. After application of the palladium layer, heat-treated under vacuum is conducted at a pressure of (2-8)⋅ 105 mm Hg, temperature of 250°C for 20-30 minutes. As a result, palladium silicide Pd2Si is formed.
EFFECT: invention reduces drag, improves process efficiency, improves parameters, improves quality and increases yield percentage.
SUBSTANCE: method of increasing the threshold barrier voltage of a transistor based on gallium nitride (GaN), which includes creating gate p-GaN mesa on the surface of the silicon wafer with epitaxial heterostructure of GaN/AlGaN/GaN type, inter-instrument mesa-isolation, forming ohmic contacts to the areas of the transistor drain and source, forming a two-layer resistive mask by lithographic methods, cleaning of the surface of the semiconductor, deposition of thin films of gate metallization, removing of the plate from the vacuum chamber of the evaporator, removal of the resistive mask, prior to the evaporation of thin films of gate metallization the plate is subjected to treatment in an atmosphere of atomic hydrogen for t=10-60 seconds at a temperature of t=20-150°C and flow density of hydrogen atoms on the surface of the plate, equal to 1013-1016 at. cm-2 c-1.
EFFECT: increase in the threshold barrier voltage of the GaN transistor when applying barrier metal films to the p-GaN gate area with a high electronic work function.
5 cl, 3 dwg