A method for improving the performance of tddb in the etching process of the upper electrode of the metal capacitor

Abstract

The invention discloses a method of improving TDDB (Time Dependent Dielectric Breakdown) performance during a metal capacitor top electrode etch process. Photoetching is carried out on the top electrode; after a photoresist is removed by wet etching, a mixed gas is used for cleaning the surface of the capacitor, H ions introduced during etch and cleaning processes are removed, the anti-breakdown performance of the capacitor is improved, and failure of a wafer is avoided.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for improving TDDB performance in the metal capacitor upper electrode etching process. Background technique [0002] In semiconductor process integration, a metal / dielectric / metal structure is used to manufacture capacitors, such as figure 1 As shown, the silicon nitride SiN dielectric layer and the titanium nitride TiN metal layer are sequentially deposited on the aluminum Al metal layer, the titanium nitride TiN metal layer is used as the upper electrode, and the aluminum Al metal layer is used as the lower electrode. etch to get a metal / dielectric / metal capacitor. [0003] The process of etching the upper electrode is called Metal Capacitor Top (MCT for short) etching process. The MCT etching process includes the following steps: [0004] Step 1, performing photolithography on the upper electrode; [0005] Such as figure 2 As shown, the wafer deposited ...

AI Technical Summary

Problems solved by technology

[0012] In step 2, cleaning after etching is one of the important steps in the semiconductor process. The wafer is cleaned in a special chemical solvent for a certain period of time to remove the reaction by-products on the surface, because the solvent will also react with the surface material. If the cleaning exceeds the set This process problem is called over-cleaning Over Dip. Over-cleaning in the metal capacitor upper electrode etching process will cause TDDB problems. TDDB (Time Dependent Dielectric Breakdown) is a time-dependent dielectric Breakdown, TDDB is one of the reliability indicators for evaluating the quality of the dielectric layer. A constant voltage is applied across the device to make the device in an accumulation state. After a period of time, the dielectric will break down. If the TDDB performance of the device decreases, the capacitor will easily break down and cause the chip to fail

Images