Buried layer alignment mark and manufacturing method thereof

Abstract

The invention relates to the technical field of semiconductor integrated circuit manufacturing, in particular to a buried layer alignment mark and a manufacturing method thereof. The manufacturing method of the buried layer alignment mark comprises the following steps: providing a semiconductor substrate, wherein the semiconductor substrate comprises a first surface and a second surface which are opposite to each other; forming an interlayer spacer layer on the first surface of the semiconductor substrate; defining an alignment mark pattern on the interlayer spacer layer; according to the alignment mark pattern, etching to remove the interlayer spacing layer outside the alignment mark pattern to form an alignment mark structure; exposing the first surface of the semiconductor substrate outside the alignment mark; and forming an epitaxial layer on the semiconductor substrate, so that the epitaxial layer covers the alignment mark structure and the exposed first surface of the semiconductor substrate. The buried layer alignment mark is manufactured by the method. According to the invention, the problem that the alignment mark is not clear and the alignment accuracy is not improved in the prior art can be solved.

Description

technical field [0001] The present application relates to the technical field of semiconductor integrated circuit manufacturing, in particular to a buried layer alignment mark and a manufacturing method thereof. Background technique [0002] Buried layer technology is widely used in semiconductor processes, for example, bipolar semiconductor devices, image sensors and Bi-CMOS devices. Taking a bipolar semiconductor device as an example, the collector of the transistor needs to be drawn upward from the bottom layer of the device, thereby increasing the series resistance of the collector, which is not conducive to circuit performance. In order to provide a current low-resistance channel for its collector and reduce the series resistance of its collector, a buried layer is usually formed in the substrate of the device in advance, and then an epitaxial layer is formed, and the buried layer is formed in the epitaxial layer. Aligned collector. Therefore, in such devices, the bur...

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Problems solved by technology

[0005] The present application provides a buried layer alignment mark and its manufacturing method, which can solve the problems in the related art that the alignment mark is not clear and is not conducive to the alignment accuracy

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