Silicon micro condenser microphone chip and its preparing method

Abstract

The invention discloses a silicon micro-condenser microphone chip, which comprises a silicon substrate with a perforated back board on top. Wherein, the said back board comprises a continual doping layer on top of said substrate with a plurality of acoustics holes by etching the continual doping layer or also a silicon material layer under the doping layer. This invention overcomes the problem to prepare back board and perforation with deep-selective enriched boron, and provides a simple and practical technique for industrial production.

Description

technical field [0001] The invention relates to the field of semiconductor devices, in particular to a silicon microcapacitor microphone chip and a preparation method thereof. Background technique [0002] The silicon microcapacitor microphone is a new type of microphone, which usually consists of a silicon chip part and a peripheral circuit part forming a silicon microcapacitor. Among them, the silicon microcapacitor chip part is the core of the microphone, which is manufactured on a silicon substrate through a complex bulk etching process using modern VLSI technology. The silicon microcapacitor chip part is composed of a silicon substrate and a perforated backplane or an acoustic hole backplane, an air gap, an isolation layer, a vibrating film / metal film and a metal electrode. Due to the complexity of its manufacturing process, with the development of technology, many new structures and their preparation methods are constantly being proposed. [0003] It is known that ab...

AI Technical Summary

Problems solved by technology

The deep boron diffusion takes a long time (generally more than 20 hours), and the deep boron diffusion causes the silicon substrate to warp at the edge, making it difficult to manufacture various processes after the deep boron diffusion

In particular, large silicon substrates (such as 4-inch or larger substrates) for production are greatly affected

[0008] 3) Due to the anisotropy of silicon itself in the etching solution, for silicon microcapacitor sound transmission chips, the thickness of the backplane is required to be between 12 microns and 20 microns. In this way, the backplane prepared with deep concentrated boron diffusion The perforation cannot be too small, therefore, the size of the silicon microcapacitor microphone chip cannot be too small, which makes the cost of the silicon microcapacitor microphone chip relatively high during mass production

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