Method of pre-metal dielectric (PMD) stress recovery

Abstract

The invention discloses a method of pre-metal dielectric (PMD) stress recovery. The PMD possesses a contact hole and the contact hole is just cleaned. The method comprises the following steps: irradiating the PMD by using an ultraviolet lamp; measuring a first wafer flexibility after the PMD is generated and a second wafer flexibility when ultraviolet irradiation is performed; comparing the first wafer flexibility with the second wafer flexibility; stopping the ultraviolet irradiation if a flexibility difference is less than 10 micrometers, otherwise, continuing the ultraviolet irradiation. By using the invention, a problem of stress loss caused by the PMD which absorbs water during a conductor device manufacture process can be effectively solved; the water absorbed by the PMD during technology links, such as chemically mechanical polishing, cleaning and the like, can be effectively removed so that stress of the PMD can be recovered; performance of a manufactured semiconductor device can be raised. The method of the invention has advantages of low implementation costs, simple processes, short processing time, economy, high efficiency and utility.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing technology, in particular to a method for stress recovery of a pre-metal dielectric layer. Background technique [0002] With the gradual increase in the integration and performance requirements of VLSI, the device size is continuously reduced proportionally, and semiconductor technology is developing towards a technology node with a feature size of 45nm or even smaller. With the reduction of feature size, the semiconductor manufacturing process becomes more and more sophisticated and complex, and there are more and more factors affecting the performance of semiconductor devices. [0003] The pre-metal dielectric layer (Pre-Metal Dielectric, PMD) is used as an isolation layer between the device and the interconnection metal layer and a protective layer to protect the semiconductor device from impurity particles, and its stress effect directly affects the performance of the semiconductor ...

AI Technical Summary

Problems solved by technology

However, since the surface of the pre-metal dielectric layer has been planarized after chemical mechanical polishing, plasma or heating treatments on the pre-metal dielectric layer can only effectively remove the moisture in the surface layer of the pre-metal dielectric layer.

At this time, the moisture inside the metal pre-dielectric layer becomes more difficult to remove, and strengthening the intensity of plasma or heat treatment will increase the risk of damage to semiconductor devices

At the same time, in the cleaning step after chemical mechanical polishing, the pre-metal dielectric layer also absorbs water, so that the effect of restoring the stress of the pre-metal dielectric layer by the prior art is not ideal.

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