Optimization Method of Back Pressure in Tungsten Deposition Process

Abstract

The invention provides an optimization method for the back side pressure in the tungsten deposition process. The method includes the steps that the back side pressures in the steps of pre-deposition, nucleation and bulk deposition are compared with the yield, changes along with the back side pressures are found, and the changing result of the yield or the uniformity is obtained; the optimal values of the back side pressures in the three steps are obtained; a preset shutdown maintenance threshold value of the number of using days is set for a heater; when the value of the number of the using days of the heater is reached, the heater is detached and inverted, and the surface of the heater is soaked in hydrogen peroxide solution; after a preset cleaning time, the heater is taken out and wiped with deionized water and isopropyl alcohol; a back pressure groove of the heater is viewed, and it is guaranteed that tungsten residues have totally fallen off; the heater is assembled again, and the tungsten deposition process is executed with the optimal values of all the back side pressures. Through the method, the optimal back pressure conditions in different steps are obtained, the optimal back pressure optimization conditions can be utilized, the back side pressure of wafers is controlled and stabilized, and the step coverage rate is increased.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing technology, in particular, the invention relates to a method for optimizing the back pressure of a tungsten (W) deposition process. Background technique [0002] In the 200mm semiconductor process flow, tungsten (Tungsten) CVD (Chemical Vapor Deposition) process is widely used in the filling of contacts, vias, and plugs. Almost all tungsten deposition processes are divided into three main hole filling steps: pre-deposition (Soak), nucleation (Nucleation) and bulk deposition (Bulk deposition). In these three process steps, many studies have shown that the wafer back pressure control in the tungsten CVD process has greatly affected the step coverage of tungsten filling and the final product yield (Yield). Since the tungsten process is divided into multi-step processes, the pressure requirements on the back of the wafer in each process step are different. Therefore, if the pressu...

AI Technical Summary

Problems solved by technology

Since the tungsten process is divided into multi-step processes, the pressure requirements on the back of the wafer in each process step are different. Therefore, if the pressure is not stable, it will lead to poor process uniformity, which in turn will lead to poor step coverage.

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