Method for forming structure with high depth-to-width ratio pattern

Abstract

The invention relates to a method for forming a structure with a high depth-to-width ratio pattern. The method includes the following steps: step S1. providing a semiconductor substrate, wherein an etching stop layer, an injection barrier layer and a patterned mask layer are covered on the upper surface of the semiconductor substrate in sequence; step S2. performing anisotropic etching on the injection barrier layer, stopping, by the anisotropic etching, at the etching stop layer to form a groove; step S3. forming a thin film layer on the upper surface and the side wall of the groove by usingatomic layer deposition, narrowing an opening of the groove through the thin film layer, adjusting the depth-to-width ratio of the groove, and then forming the structure with the high depth-to-width ratio pattern. The method has the advantages that as the thin film layer is formed on the upper surface and the side wall of the groove on the traditional thin film structure by using an ALD (atomic layer deposition) technology, and the opening of the groove is adjusted by adjusting the thickness of the thin film layer to form the high depth-to-width ratio pattern, the problems of small depth-to-width ratio of the traditional lithography process and the topography caused by the multi-layer lithography technology are solved.

Description

Technical field [0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a method for forming a structure with a high aspect ratio pattern. Background technique [0002] In the Complementary Metal Oxide Semiconductor (CMOS) image sensor chip manufacturing process, high-energy ion implantation is performed on the structure of high aspect ratio graphics to achieve isolation between each pixel, thereby improving image clarity. To achieve high pixels per unit area. [0003] In some high-energy ion implantation processes, the line width is required to be 0.15 μm, the photoresist thickness is 0.4 μm, and the aspect ratio is greater than 20:1. If a traditional dielectric film structure is used, a high aspect ratio cannot be achieved through a traditional photolithography process (the aspect ratio is less than 5:1), and a small line width cannot be achieved. Therefore, in order to achieve a high aspect ratio, Tri-Layer technology i...

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Problems solved by technology

[0004] However, there are certain defects in the multilayer lithography technology. If the ratio of the thickness of the injection barrier layer to the critical dimension is too large, the injection barrier layer will be in the shape of a cone or a bowling ball; if the thickness of the injection barrier layer is too large, the hard mask layer is prone to edge over-etching, resulting in burrs at the edge of the implant barrier layer

All of the above defects will affect high-energy ion implantation and device characteristics

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