A method for reduce spherical defects in deep submicron photolithography process

Abstract

The invention discloses a method for reducing spherical defects in deep sub-micron photolithography process, which comprises the following steps: 1) placing a wafer on a cold plate for cooling beforegluing; 2) coating the wafer in step 1) with bottom anti-reflective coating, standing for 60-100s, then baking on a high-temperature hot plate, and then cooling to room temperature; 3) coating the wafer cooled to room temperature with photoresist, then baking the wafer on a low-temperature hot plate, cooling the wafer on a cold plate to room temperature, and then carrying out edge exposure; 4) transfer that edge-exposed wafer to a low-temperature hot plate for exposure, bake, and then transferring to a cold plate for cooling to room temperature; 5) developing the wafer which has completed thestep 4), hardening the wafer on the low-temperature hot plate after the development is completed, and then transferring the hardened film to the cold plate for cooling to room temperature. As that wafer is stationary for 60 to 100 seconds after the bottom anti-reflection coating is coated, the invention ensures the consistency of each step of the wafer process state and reduces the generation of deep sub-micron photolithography process spherical defects.

Description

technical field [0001] The invention belongs to the technical field of semiconductor wafer manufacturing, and relates to a method for reducing spherical defects in a deep submicron photolithography process. Background technique [0002] In the manufacture of semiconductor wafers, a special kind of spherical residue often appears during the deep submicron lithography process, the so-called "ball defect", such as figure 1 shown. This defect occurs on the surface of the wafer. During the subsequent etching, deposition or ion implantation of the wafer, the spherical defect will affect the morphology after etching and the depth of ion implantation, and cause the target quality of the deposition process to fail. deviation. Ultimately, it affects the yield of the wafer. [0003] Characterized by energy scattering spectroscopy, the main components of spherical defects are C and O. Among the materials involved in the entire semiconductor wafer manufacturing, they have the greatest...

AI Technical Summary

Problems solved by technology

While the wafer is waiting, the rotary motor will lift the wafer and expose it to the cavity; at this time, the photoresist dust and other substances existing on the upper part of the cavity will not be sucked away by the exhaust air, but will fall on the top of the cavity. on the wafer, thereby forming spherical defects

[0005] In addition, when investigating the experimental results in the literature, it was found that when the coating speed is less than a certain value, the number of spherical defects will be reduced

However, due to the requirements of photolithography and subsequent processes on the thickness of photoresist, it is not feasible to reduce the spherical defects by reducing the coating speed in order to ensure that the thickness of the coating film is within a certain specification.

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