A Method of Improving the Performance of Metal Capacitor TDDB

Abstract

The invention provides a method for improving the TDDB performance of a metal capacitor. The method includes the steps of etching and cleaning an upper electrode to expose a portion of a dielectric layer; performing an alloying process to repair the exposed portion of the dielectric layer; forming a silicon oxynitride layer, and covering the upper electrode and the exposed portion of the dielectric layer with the silicon oxynitride layer; performing photoetching; and etching and cleaning a lower electrode. Based on the traditional process, the method of the invention can repair the plasma damage to the dielectric layer on by increasing the alloying process and improve the breakdown resistance of the dielectric, thereby improving the TDDB performance and increasing the use time of a chip.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for improving the performance of a metal capacitor TDDB. Background technique [0002] Metal capacitors are commonly used devices in IC chip manufacturing. However, during the production process of the metal capacitor, after the metal capacitor layer is dry-etched, the edge of the capacitor is susceptible to plasma damage5 (plasma damage, such as figure 1 shown), in addition, the subsequent metal dry etching will also have an impact on the capacitor edge. [0003] Please combine figure 1 and figure 2 , the traditional manufacturing process of metal capacitors includes: [0004] Step 1, metal capacitor top electrode 4 etching (metal capacitor top etch, MCT-ET), and cleaning; [0005] Step 2, SiON (silicon oxynitride) deposition; [0006] Step 3, photolithography; [0007] Step 4, the lower electrode (including the first metal layer 1 and the second metal...

AI Technical Summary

Problems solved by technology

[0008] When the required metal capacitance is larger, when the same dielectric 3 is selected, the thickness of the capacitor dielectric 3 will become thinner, and the influence of plasma damage will also become greater, which will easily cause TDDB problems, TDDB (time dependent Dielectric breakdown) is a time-related electrolyte breakdown, which is one of the reliability standards 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. This The time elapsed during this period is the life under this condition. If the TDDB performance of the device decreases, the capacitor will easily break down and cause the chip to fail.

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