Method for improving OVL alignment problem of epitaxial layer

The invention discloses a method for improving an OVL alignment problem of an epitaxial layer. The method comprises the following steps: providing a substrate; a measurement mark is formed on the surface layer of the substrate, the measurement mark is a groove, and the side wall of the groove is recessed in the direction away from the center of the groove; and forming an epitaxial layer on the surface of the substrate, wherein a recess is formed in the part, covering the measurement identifier, of the epitaxial layer. According to the scheme, the problem that in the prior art, the appearance of the measurement mark is influenced by the thickness increase of the epitaxial layer, so that the measurement mark outer frame of the photoetching front layer is seriously deformed, and finally the measurement fails can be solved. 本申请公开了一种改善外延层OVL对位问题的方法，包括：提供一衬底；在所述衬底表层形成量测标识，所述量测标识为一凹槽，所述凹槽的侧壁向远离凹槽中心的方向凹陷；在所述衬底表面形成外延层，所述外延层覆盖所述量测标识的部分形成凹陷。本申请通过上述方案，能够解决相关技术中外延层厚度增加会影响量测标识的形貌,使得光刻前层的量测标识外框变形严重，最终导致量测失败的问题。