ionic-beam passivation of metals
Major components of topologies of micro-components and microwave hybrid-integrated circuits are metal layers with preset physical and chemical characteristics. Unlike ionic-beam processing of semiconductors which purpose consists first of all in a change of electric characteristics of a material, ionic implantation of metals at the present stage is of interest basically for controllable management of chemical activity of a substance that underlies lithographic processes and can be applied for quality improvement of etching topological elements, for corrosion and chemical protection of products, and for working out of prospective methods of ionic lithographs, including ones without resisting.
Effects of ionic-stimulation changes of physical and chemical properties of metal coverings find numerous applications in microelectronic device technology. Advantages of their use are connected with the increase of operational characteristics of microcircuits, manufacturing of new classes of thin-film resistors, effective adjustment of nominal values of electro-resistances, and also with the simplicity of technological processes realization on the basis of the established effects. A number of technological possibilities are connected with implantation management of chemical and corrosion activity of materials.
Contacts of diverse metals are widely applied as a part of micro-devices and integrated circuits. Thus, for example, the contact of aluminum to precious metals can lead to breaking its protective oxide layer. Ionic-implantation processing of such compositions can significantly raise their firmness to electro-corrosion processes.
Possibly, in plants of processing metal products, for the purpose of increasing their corrosion characteristics, ionic implantation will be used as directly, and in a combination with deposition of a thin gold covering that will provide intensive moving of components and will raise the process efficiency by that.
The particular interest is caused by a possibility of modifying electro-physical parameters of thin films of transitive metals that is caused by a prospect of their use as thin-film resistors and capacitors with small noise level and high frequency characteristics. Unique feature of thin-film elements of this kind is a possibility to adjust values of temperature factor of resistance. Selecting a corresponding dose of an irradiation and a temperature interval of their manufacturing, it is possible to control a temperature factor of resistance in a wide range of nominal values.
A high selectivity of the ionic implantation method leads to a realization of a group-forming of resistors with different nominal values and temperature factor values of resistances. It allows one to reduce overall dimensions of micro-devices and integrated circuits and to expand their functionality.
The effect of conductivities changes of the irradiated film coverings is connected with a number of physical and structurally-chemical factors. It is considered, for example, that the increase of nominal value of electro-resistance of the implanted metals is defined by reduction of its thickness at the expense of sputtering effects. However it is experimentally established that the contribution of ionic sputtering is in 3 – 5 times less than a total gain of the resistance. As mechanisms, the processes of forming chemical compounds of atoms of a matrix with the introduced impurity, and activation of polluting impurity by an ionic bunch are considered: a desorption of the absorbed gases; transition to island structure at the high irradiation doses; consolidations of borders and re-crystallization. Processes of activation of the introduced and initial impurity are allocated as basic mechanism of ionic-stimulation changes of metal conductivities.