Method for forming groove and method for fabricating semiconductor device

Abstract

The invention provides a method for forming a groove and a method for fabricating a semiconductor device. The method for forming the groove is used for forming a groove in a semiconductor structure. The semiconductor structure comprises a port area and a unit area. The method comprises the following steps: an oxide layer forming method for forming an oxide layer on the surface of a silicon sheet; a photoresist layer forming step for forming a photoresist layer on the surface of the oxide layer; a pattern forming step for photoetching the photoresist layer to form a groove pattern part corresponding to the groove, etching the oxide layer by use of the photoresist layer in which a pattern is formed, thereby forming the pattern corresponding to the groove pattern part in the oxide layer; an oxide layer first etching step for removing the photoresist layer on the unit area and etching the oxide layer by use of the remaining photoresist layer; a groove etching step for forming a groove in the unit area by use of the groove pattern part; a photoresist layer removing step for removing the remaining photoresist layer; and an oxide layer second etching step for etching the oxide layer after removing the photoresist layer.

Description

technical field [0001] The present invention relates to the field of semiconductor manufacturing, and more specifically, the present invention relates to a trench forming method and a semiconductor device manufacturing method using the trench forming method. Background technique [0002] In the manufacturing process of various semiconductor devices, trench etching is generally required to form trench structures, for example, shallow trench etching is performed to form shallow trench isolation (shallow trench isolation, STI). [0003] Generally, in the groove etching formation method, a photoresist is coated first and photoresist is carried out to the photoresist, then the hard mask is etched by using the photoresist pattern after photolithography, and finally the hard mask is etched by etching. Out of the hard mask pattern to etch trenches. Thus, lithography of the photoresist defines a lithography CD, and hardmask etch follows a hardmask etch CD, and these two CDs (i.e., l...

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Problems solved by technology

[0007] Thus, when the photoresist 4 is placed on the hard mask 3 (see image 3 ), and to form the grooves a trench pattern of photoresist 4 was formed ( image 3 The groove patterns h11, h12, h13 near the adjacent areas of the port area A and the cell area B may have size unevenness

[0008] In other words, it is originally expected to form a plurality of trenches with uniform trench sizes, but due to the non-uniformity of the hard mask 3 at the adjacent regions of the port region A and the cell region B, the phase of the port region A and the cell region B eventually results. Groove patterns h11, h12, h13 at adjacent regions may have non-uniform size

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