Mold for making alkali metal wax envelope, and methods of making and using it

Abstract

The invention discloses a mold for making an alkali metal wax package, and a method for preparing and using the mold. The mold includes a silicon base; the silicon base includes: a semi-structural spacer located at the edge of the silicon base; and a central part of the silicon base; The upper surface of the central part of the silicon substrate is indented to form a number of wax-package bearing cavities; a load-carrying cavity isolator is formed between adjacent wax-package bearing cavities; a release sacrificial layer is formed on the upper surface of the silicon substrate, and the upper surface of the release sacrificial layer is far away from the silicon substrate A paraffin layer is formed; a cavity for carrying alkali metal is formed on the side of the paraffin layer away from the release sacrificial layer; the semi-structural isolation body includes corrosion release holes. The invention can reliably and controllably realize the mass production of uniform and consistent alkali metal wax package arrays, is fully compatible with MEMS and microelectronic technology, has simple and easy process flow, and strong operability; and the wax package mold can be reused, which is beneficial to avoid The waste of raw materials can effectively reduce the cost of mass production.

Description

technical field [0001] The invention relates to the technical field of vacuum electronics. More specifically, it relates to a mold for making an alkali metal wax envelope, and methods of making and using it. Background technique [0002] Time measurement technology plays an important role in the progress and development of human society. With the deepening of scientific research and the development of science and technology, the requirements for time measurement are getting higher and higher, and the time measurement equipment manufactured is becoming more and more advanced. At present, atomic clocks are The most accurate time measurement device. An atomic clock is a device that provides a standard frequency signal based on the quantum transition frequency. Its most basic application is as a time frequency standard. In addition, atomic clocks are also widely used in many fields such as global navigation satellite system (GNSS), basic scientific research, communication, wea...

AI Technical Summary

Problems solved by technology

Since anodic bonding requires a high temperature of about 400°C, and the melting point of alkali metals is mostly between 20-40°C (Rb is 39.3°C, Cs is 28.4°C), it is difficult to reliably dispose of alkali metals before completing the bonding package

Some technical approaches to avoid this problem have been proposed one after another, but each has its own disadvantages: the method of using alkali metal chloride and barium nitride to generate alkali metal in situ will leave impurities in the gas chamber, causing the gas chamber to absorb energy, resulting in frequency drift of the device , reduce the accuracy of atomic clocks; use microchannels to connect double cavities, and put alkali metals into them after molding. The material consumption is large, the controllability is poor, and wax sealing is required, resulting in low efficiency and yield; some commonly used polymer films wrap alkali metals to form packages. method, the special equipment required and the microfabrication process are incompatible, resulting in difficulties in mass production, and the polymer will reduce the long-term stability of the atomic clock system

However, these techniques have not solved the problem of effective separation of silicon-based molds encapsulated with alkali metal wax.

Direct physical detachment will lead to a decrease in the yield of the wax package; and the separation of the corroded silicon substrate will completely dissolve the wax package mold and cannot be reused

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