Fused silica glass is a material of choice for micromechanical, microfluidic, and optical devices due to its chemical resistance, optical, electrical, and mechanical performance. Wet etching is the key method for fabricating of such microdevices. Protective mask integrity is a big challenge due extremely aggressive properties of etching solution. Here, we propose multilevel microstructures fabrication route based on fused silica deep etching through a stepped mask. First, we provide an analysis of a fused silica dissolution mechanism in buffered oxide etching (BOE) solution and calculate the main fluoride fractions like $${HF}_{2}^{-}$$ HF 2 - , $${F}^{-}$$ F - , $${(HF)}_{2}$$ ( H F ) 2 as a function of pH and NH4F:HF ratio. Then, we experimentally investigate the influence of BOE composition (1:1–14:1) on the mask resistance, etch rate and profile isotropy during deep etching through a metal/photoresist mask. Finally, we demonstrate a high-quality multilevel over-200 μm etching process with the rate up to 3 μm/min, which could be of a great interest for advanced microdevices with flexure suspensions, inertial masses, microchannels, and through-wafer holes.

Present the results of study on the development of the technology for the recycling of hazardous waste of organosilicon production to produce grouting solution. It is shown that during hydrolytic esterification of bottoms from production of phenyltrichlorsilane is obtained product which can be used as a grouting solution to isolate the inflow of oilfield water. It is established that the quality of the product is affected by the ratio of reagents, chloride ion content, temperature and duration of polycondensation.

The results of the development and manufacture of an integrated membrane-free sensor for the control of accurate dilution of liquid samples on the microfluidic chip are presented. The proposed type of devices is intended for direct precise measurements of liquid flow rate in microchannels of laboratories-on-chip, including point-of-care systems. The sensor topology was optimized based on the numerical simulation results and technological requirements. The main characteristic of the developed sensor is the lack of a membrane in the design while maintaining the sensitivity and accuracy of the device at the level of a commercial membrane analogue. The fully biocompatible sensor was manufactured using standard microelectronics and soft lithography technologies. In order to optimize the sensor design, 32 different topologies of the device were tested. The integration of the flow sensors on the chip allows to significantly reduce the dead volume of the hydrodynamic system and to control the amount of liquid entering the individual reservoirs of the microfluidic chip. The sensor occupies an area of (210 x 140) um2 in the channel and is characterized by a relative error of 5% in the flow rate range of 100-1000 ul/min. microfluidics, lab-on-chip, calorimetric flow sensor, thermoresistive sensor, numerical simulation, hydrodynamics, complementary metal-oxide-semiconductor, microtechnologies Devices were made at the BMSTU Nanofabrication Facility (FMN Laboratory, FMNS REC, ID 74300).

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