Method for semiconductor selective etching and bsi image sensor

Abstract

A method of selectively etching a semiconductor device and manufacturing a BSI image sensor device includes etching a doped silicon substrate with an HNA solution for a predetermined time duration to obtain an etching solution having a concentration C1 of nitrite ions, etching the semiconductor device using the obtained etching solution. Etching the semiconductor device requires an initial concentration C0 of nitride ions that is lower than C1. The HNA solution comprises a hydrofluoric acid (HF), a nitric acid (HNO3), and a acetic acid (CH3COOH). The BSI image sensor device will have a uniform thickness when etched using the thus obtained etching solution.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to wet etching of integrated circuits, and more particularly to a selective etching process in the manufacturing of BSI image sensors.[0002]With the development and progress of information technology, design and manufacturing of semiconductor integrated circuits has become a sign of the national strength and innovation ability of enterprises. The manufacturing process of an integrated circuit includes wafer fabrication, polishing, oxidation, lithography, epitaxial growth, etching, packaging, and other processes. Chemical etching or chemical mechanical polishing is one of the key technological processes for removing a portion of an integrated circuit. Chemical etching includes wet etching and dry etching. The difference between the wet and dry etching is that wet etching uses a solution or solvent whereas dry etching uses a chemical etchant gas for etching.[0003]A conventional CMOS image sensor includes a semiconductor su...

AI Technical Summary

Benefits of technology

The present invention provides a method for selectively etching semiconductor substrates with a uniform thickness, using an etching solution containing nitrite ions. The etching process requires an initial concentration of nitride ions lower than the concentration of the etching solution. This method allows for stable and efficient etching of semiconductor devices during mass production. Additionally, this invention also includes a method for manufacturing a BSI image sensor device involving selectively etching the substrate and sequentially forming an optical filter and micro-lenses on the etched substrate. This method ensures that the BSI image sensor device has a uniform thickness and optimal performance.

Problems solved by technology

However, BSI CMOS image sensor devices manufactured with conventional processes tend to have relatively low yield and poor performance.

The reasons can be, for example, low quantum efficiency, unclear image, non-uniformity of light, uneven thickness of the semiconductor substrate due to instability of etching rate, thereby affecting the optical path of light entering the CMOS image sensor.

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