RU1815251C - Method for manufacture of flexible suspension from quartz glass - Google Patents

Abstract

The invention relates to a technology for manufacturing quartz accelerometer suspensions of dimensional etching. The essence of the invention lies in the fact that selective etching of quartz is carried out in two stages: on the first on both sides of the workpiece, grooves are formed simultaneously in the suspension groove zone to a depth, the total value of which is set equal to the nominal thickness of the working jumpers, then, in the second stage, the grooves are etched simultaneously and working jumpers until they touch in the process of etching adjacent walls of the grooves, and in the process of forming working jumpers, the etching zone of working jumpers increases discretely in proportion to the etching depth.

Description

rykh is equal to the nominal thickness of the working jumper of the suspension.

This feature allows you to pre-set the final thickness of the working jumper with its control by simple technological means - a micrometer. In addition, the formation of the groove and the working jumpers simultaneously during the time of the through etching of the groove allows the accuracy of obtaining a given thickness of the working bridge and ensures the simplification of the technology for producing the suspension.

The formation of the suspension working bridge with smooth thinning during the transition from the massive part of the suspension to the working part of the bridge due to the discrete increase in the etching zone in the direction of the length of the working bridge in proportion to the etching depth allows to increase the mechanical strength of the pendulum by eliminating voltage concentrators, eliminating breaks in the conductive film sprayed onto the working jumpers and at the same time reduces ghosting due to the successive application of selective etching with various masks.

The message during the etching of the quartz precursor of the reciprocating helical movement in the direction of the least hydrodynamic resistance of the preform under conditions of laminar flow around the preform with the etchant ensures uniform etching of the quartz preform including the working jumpers by effectively removing etching products from the etching zone and. access to the etching zone of the etchant. The helical reciprocating movements of the workpiece in the laminar mode, unlike the rotational one, slightly change the thermal field of the etchant liquid and at the same time effectively remove the etched products from the etched zone.

P r. A quartz glass blank KU 1 in the form of 50x50 bars is cut into square bars with an allowance for turning in diameter to form blanks of 025 size, 0.7 mm thick. After grinding, finishing and polishing the workpieces, plates of 025,, 500 mm with a roughness class of R2 0.050 are obtained.

Then, alternately, protection is formed on both surfaces of the workpiece plates and selective etching is carried out,

In a quartz billet with a thickness of 500 mm by selective etching, a groove is formed in the form of grooves of the same depth, the total value of which is 1.2-1.3 nominal thickness of the working jumper

suspension. Ammonium bifluoride is used as an etchant, and a structure of 1.5–2 µm thick is used as a protective mask — chromium-copper-chromium — a structure sprayed onto both surfaces

quartz billet.

Selective etching is carried out in ammonium bifluoride for 20 min; therefore, the manufacturing technology provides for galvanic build-up of a copper layer

0 12 microns thick on a previously sprayed layer of Cr-Cu-Cr. The galvanic build-up of copper is carried out in the electrolyte by passing current, the electrode is connected to the rim of the suspension - the fixed part of the suspension.

5 In the manufacture of the suspension, in order to prevent breakdowns of the working jumpers, the formation of three technological jumpers between the movable and fixed parts, which are removed after the formation of the circuit on

0 suspension by electron beam.

The nominal thickness of the working bridge of the pendulum is 20 microns. Then, the protective layer is removed by etching in solutions of hydrochloric, sulfuric, nitric acids in water.

5 The protective layer is again formed and selective etching of the grooves for the working jumpers of the suspension and further etching of the grooves forming the groove of the suspension are carried out. When etching a jumper groove

0 first apply selective etching with a pattern width equal to the working length of the jumper, then discretely, by changing the pattern, increase the width of the window of the pattern in the direction of the length of the jumper and again

5 etch grooves and jumpers. The etching depth at each etching step is selected from the condition of a given curvature of the transition surface of the jumper zone of the conductive track to be sprayed. For jumpers with a thickness of 20 microns and with a workpiece thickness of 500 microns, it is sufficient to use three photomasks with a window width of 1.5; 2.0 and 2.5 mm with a nominal length of the working jumper 5 equal to 1.5 mm.

Etching of the preform is completed after through etching of the groove. The instant of formation of the through etch c. the groove can be determined using various sensors detecting the discontinuity of the quartz material in the etching zone, for example, electrical contacts.

The etching of quartz preforms of the claimed method is carried out in ammonium bifluoride.

5 heated to 75 ± 1 ° C in dynamic mode. The etching is carried out in a fluoroplastic reaction vessel in which a fluoroplastic cassette with blanks is placed, which is driven by selective etching.

A positive effect of the invention is an increase in the quality of manufacture of quartz suspensions, a reduction in the complexity of manufacturing due to the use of group technology of operations for applying protection and etching.

Claims (1)

SUMMARY OF THE INVENTION A method for manufacturing an elastic suspension made of quartz glass, comprising two-sided polishing of a quartz glass preform, forming a groove separating the moving part of the suspension from the base and working jumpers, vacuum-forming a metal film of a capacitive converter on both sides of the moving part of the suspension, characterized in that in order to increase the mechanical strength of the suspension of the pendulum by reducing the stress concentrators in the necks of the working jumpers and reducing the undercut by increasing the etching uniformity, grooves of the same depth are formed simultaneously on both surfaces of the workpiece in the groove area at the same time, the total value of which is set equal to 1.2-1.3 of the nominal thickness of the suspension working bridge, then selective working etching from opposite surfaces of the workpiece is carried out and the grooves of the groove until the adjacent walls of the grooves touch, and the etching of the working jumpers to the final thickness, and etching is carried out discretely at least 2 times, at each etching step, the etching area is increased in the direction of the length of the web depending on the etching depth, and reciprocating helical movements are reported.