For the first time, an experimental dependence of the grain size and mechanical properties of a thin-film aluminum material on the dose of short-wave radiation has been obtained. A thin film of aluminum was formed on a silicon substrate using magnetron sputtering. The effect of a decrease in mechanical strength and biaxial elastic modulus with increasing radiation dose was identified. This effect is explained by a decrease in grain size and roughness on a thin-film aluminum membrane. For the microscopically measured range of aluminum grain sizes, the inverse Hall-Petch relation is used. During the research, it was determined that during irradiation the number of grain boundaries and the number of grains themselves increases, which leads to an increase in the likelihood of deformation.

The principle of modifying the mechanical properties of thin-film membrane structures of arbitrary shape by a non-contact method was proposed, implemented and explained for the first time. The idea was tested on a thin-film aluminum membrane formed by the magnetron method on a silicon substrate. The external influence was carried out through a cyclic load in the form of releasing and supplying excess air pressure to the membrane. As a result of repeated impacts, the physical properties of materials (grain size and roughness) and mechanical properties (internal mechanical stresses and critical overpressure) change. Changing the magnitude of residual mechanical stresses in the membrane material allows the formation of a surface with the required curvature value. In this work, after a cyclic load with a pressure equal to half the critical pressure, the following effects were revealed: the deflection of the membrane in the absence of external influence increased by more than an order of magnitude, the structure passed into a plastic type of deformation, the critical burst pressure decreased by several tens of percent. The use of this methodology makes it possible to create new materials with unique mechanical properties.

Представлены результаты исследования влияния толщины тонкопленочных покрытий на величину остаточных напряжений в интерфейсе пленка–подложка. В процессе эксперимента использована Si-подложка с тонкой пленкой Al2O3, сформированной магнетронным способом. Впервые показана взаимосвязь формы подложки и уровня остаточных напряжений в тонкопленочном покрытии. Применена модернизированная методика исследования остаточных напряжений в тонкопленочных покрытиях, позволяющая определять механические напряжения в локальных областях тонкой пленки.

In this paper, the experimental methodology for the single-crystal circular plate deformation measurement and subsequent procedure for the quantitation of its mechanical properties are developed. The procedure is based on a new numerical-analytical solution of non-linear boundary-value problem for finite deformations of a circular anisotropic plate. Using the developed method, a study of the deformation of single-crystal circular plates formed on the basis of a silicon-on-insulator structure was carried out. The values of residual stresses are determined and it is shown that the presence of these stresses increases the flexural rigidity of the plate by several times.

For the first time in Russia, we present a technology for temporary wafer bonding, which is used to form through holes in silicon (through-silica via (TSV) structures) with a high aspect ratio of depth to diameter (more than 10 to 1), as well as a method for transferring alignment marks from the front to the back side of a thin Si wafer, consisting in the use of a glass carrier plate, which allows for a sufficient amount of deflection of the assembly for lithography. The modernized operating parameters of Si-glass bonding, which consist in controlling the cooling rate of the plates and applying pressure to the plates during their cooling phase, ensure a reduction in the deflection of the resulting assembly by 75

The features of thin-film membranes, which are formed above round holes in silicon substrates using the Bosch-process are considered. The membrane has a complex shape due to the presence of the stress state of the initial films. The analysis of the dependence of the membrane deflection w on the supplied overpressure P is used to calculate the mechanical characteristics of the membranes. In this case, it is necessary to determine directly on the membrane its diameter, the thickness of the constituent layers, the change in the topography of the membrane surface over its entire area as the overpressure increases. Determination of the membrane diameter and the thicknesses of the constituent layers is shown by the example of p-Si*/SiNx/SiO2 and SiNx/SiO2/SiNx/SiO2 membranes. We used spectral ellipsometry, energy-dispersive X-ray spectroscopy, optical profilometry, optical microscopy. The influence of the peculiarities of the fixing conditions on the stress-strain state of membranes is shown, and the assessment is carried out by means of numerical modeling. A technique has been developed for measuring and calculating the mechanical characteristics of membranes that have an initial deflection. The calculation result is shown on the example of a membrane with an initial deflection of 2 μm --- SiNx/SiO2/SiNx/SiO2 and a membrane with an initial deflection of 30 μm --- Al/SiO2/Al. Keywords: stress, bulging method, films, thin-layer coating, film thickness, membrane, pressure blister test, residual stress, microelectromechanical systems, MEMS, silicon substrate, large deformations, strain, deflections, circular membrane, bulge testing.

Three-dimensional integration, which improves the performance of an integrated circuit by reducing die area and decreasing signal latency, is made possible by through-holes in silicon (TSV). Combining ICs in a micro-assembly and tightly connecting them vertically solves the problem with efficiency. Due to the need to minimize the characteristics of the microcircuit level, the number of transistors per unit area continues to increase. All IC components must be electrically connected to ensure proper operation. Over the years, various IP architectures have been developed to keep the path of miniaturization going. This article focuses on existing microassembly methods, ranging from two-dimensional integration (2D) to three-dimensional (3D).

The review focuses on adhesive bonding technology, which is used both for manufacturing various micro- and nanoelectronic devices, sensors and microsystems, and for assembling or integrating various components. Information on the theory of adhesive bonding mechanisms is presented. The properties and applications of four classes of polymers are reviewed: thermoplastic, ther-mosetting, elastomeric, and hybrid. The classification of different mechanisms used to initialize the curing process of adhesives is presented. Existing methods of applying polymers to the wafer surface are described. The main types of designs and principles of operation of adhesive wafer bonding equipment are presented, as well as its main suppliers. Examples of procedures and suitable process parameters are given for both wafer bonding with a continuous layer of adhesive and wafer bonding with patterned adhesive layers (also called selective or local bonding). The conditions required to improve the quality of the adhesive bond and to reduce the density of defects are specified, including cases of bonding wafers made from different materials. Adhesive wafer bonding is used for the fabrication of three-dimensional integrated circuits, and for the integration of integrated circuits with microsystems such as infrared focal plane arrays, spatial light modulators (micromirror arrays), microtip arrays for data storage systems, and laser systems. Adhesive wafer bonding is also used for the fabrication of microcavities in packaging applications, for manufacturing of liquid crystal on silicon (LcoS) components, for thin-film solar cells, for radiofrequency components, for microfuel cells, for hard disk drive microactuators, for the bioMEMS and micrototal analysis systems.

This paper shows the result of working out the operations of temporary bonding of Si-Si wafers and Si-glass wafers. The influence of materials and parameters of technological operations on the warpage of the resulting structures was investigated in order to reduce the bending of the device wafer when performing the processes of temporary bonding and thinning.

Thin-film membranes are made from alternating layers of silicon oxide and silicon nitride using a group technology. The influence of the number of layers constituting the membrane, while maintaining its thickness, on the value of mechanical strength has been studied. The burst pressure of a membrane structure 560 µm in diameter varies from 0.9 to 1.65 atm for 30 samples, depending on the number of membrane layers. The mechanical strength of the Si 3 N 4 /SiO 2 structure varies from 10.5 to 19.2 GPa. It is shown that the region of discontinuity of the structure is localized at the membrane/substrate interface.

The research paper describes the technology of temporary bonding for carrying out technological operations with semiconductor wafers with a diameter of 100 mm or less on equipment for a wafer diameter of 150 mm. The main technological processes for manufacturing a silicon substrate 300 μm thick with blind microholes (vertical grooves) 100 μm in diameter using temporary bonding technology are presented. Investigations of the elemental analysis of the formed structure of metals in blind microholes were carried out on the basis of spectral ellipsometry. Metallization was carried out by a combination of methods of atomic layer and magnetron sputtering, chemical and electrochemical deposition. The effect of expansion of the groove walls during deep plasma-chemical etching of silicon is shown. The developed technology of temporary bonding is intended for the production of silicon interposers with TSV holes, 2.5D and 3D microassemblies.

The problem for researchers and developers is inaccurate data on the mechanical strength of thin-film materials due to size effects during the transition from macro to micro levels of thicknesses of the studied layers. The objective of this work is to experimentally determine the mechanical stresses and mechanical strength of SiO 2 thin-film membranes obtained by the layer-by-layer deposition. To achieve this goal, we used analytical equipment (ellipsometer, SEM, optical profiler), computing equipment (calculations in MATLAB), and technological (system for the deposition of thin films). The mechanical strength of SiO 2 is experimentally determined by the bulge method. The value of mechanical stresses varies from 188 to 26.7 MPa with an increasing thickness of SiO 2 from 226 to 2017 nm. The determined value of the mechanical strength of silicon oxide is 1.84 GPa for a thickness of 1.5 microns and 1.27 GPa for a thickness of 2 microns. The layer-by-layer deposition of a thin film of silicon oxide by the PECVD method can reduce the value of mechanical stresses. The measured values of mechanical strength correlate well with the results of other studies.

We developed a technique for revealing and analyzing volumetric surface defects based on geomorphometric modeling, in particular, an analysis of models and maps of some morphometric variables (minimum curvature, maximum curvature, mean curvature, Gaussian curvature, unsphericity, etc.), derived from digital elevation models of a surface. The technique allows one to reveal areas of individual volume defects (cracks, film delaminations, shape deviations, etc.), to determine shape and size of both the defects themselves and adjucent modified areas, as well as to study patterns of their distribution. The technique effectiveness is exempified by defects on silicon–glass and silicon–silicon wafer assemblies, as well as a cracked Ni–W film. The technique can be promising for quality control of manufacturing and diagnostics of damages of various items, in particular, microelectronic products.

Предложен инновационный подход для переноса знаков совмещения на тонких пластинах. Реализация подхода осуществляется посредством технологии временного бондинга.. В пластине-носителе были сделаны «смотровые окна» для сканирования знаков совмещения на рабочей пластине. При помощи двухсторонней литографии и плазмохимического травления был сделан массив TSV-структур.

This paper shows the result of working out the operations of permanent bonding of Si-Si wafers and temporary bonding of Si-quartz wafers. The equipment was selected for the process of applying a thin-film material to increase the uniformity of the thickness of the adhesive, anti-adhesive, and photoresist layers. Also, the effects of flowing applied fluids to the back of the wafer are eliminated. The dependence of the thickness of the adhesive, anti-adhesive, and photoresist layers on the speed of rotation of the centrifuge was experimentally determined. It was compared with material developers' data. The curvature of the assembly does not exceed 10 μm after permanent bonding of Si-Si wafers with a diameter of 150 mm and a thickness of 675 μm. In the process of temporary bonding, the thickness of the device Si wafer after thinning was 93 ± 3 μm. The deflection of the thinned assembly does not exceed 30 μm.

A technique for detecting and analyzing volumetric surface defects has been developed. The technique is based on geomorphometric modeling, in particular, on analyzing the models and maps of a number of morphometric variables (minimum curvature, maximum curvature, mean curvature, Gaussian curvature, unsphericity curvature, etc.) calculated using digital elevation models of a surface. The technique makes it possible to identify areas of the location of individual volumetric defects (cracks, film delamination, shape deviations, etc.), to determine the shape and size of both the defects themselves and the modified areas next to them, and to study defect distribution patterns. The efficiency of the technique is demonstrated by the example of defects on assemblies of silicon-glass and silicon-silicon wafers and on a cracked Ni–W film. The technique can be promising for quality control of manufacturing and diagnostics of damage to various pieces, in particular, of microelectronic products.

The features of thin-film membranes, which are formed above round holes in silicon substrates using the Bosch-process are considered. The membrane has a complex shape due to the presence of the stress state of the initial films. The analysis of the dependence of the membrane deflection w on the supplied overpressure P is used to calculate the mechanical characteristics of the membranes. In this case, it is necessary to determine directly on the membrane its diameter, the thickness of the constituent layers, the change in the relief of the membrane surface over its entire area as the excess pressure P. Determination of the membrane diameter and the thicknesses of the constituent layers is shown by the example of p-Si*/SiNx/SiO2 and SiNх/SiО2/SiNх/SiО2 membranes. We used spectral ellipsometry, energy-dispersive X-ray spectroscopy, optical profilometry, optical microscopy. The influence of the peculiarities of the fixing conditions on the stress-strain state of membranes is shown, and the assessment is carried out by means of numerical modeling. A technique has been developed for measuring and calculating the mechanical characteristics of membranes that have an initial deflection. The calculation result is shown on the example of a membrane with an initial deflection of 2 µm – SiNх/SiО2/SiNх/SiО2 and a membrane with an initial deflection of 30 µm – Al/SiO2/Al.

Отработана операция временного бондинга с использованием в качестве носителя кварцевой пластины. Получена экспериментальная зависимость толщины адгезионного слоя от скорости вращения центрифуги. Толщина утоненной рабочей Si-пластины 0150 мм составила 93 ± 3 мкм. Прогиб утоненной структуры не превышает 30 мкм.