Method for forming metal front medium layer and its structure

Abstract

The invention relates to a forming method for metal front dielectric layer, which comprises the following steps of: forming a metal front dielectric layer depositing substrate on a semi-conductor substrate; depositing a first metal front dielectric layer on the depositing substrate by using a first CVD method; and depositing a second metal front dielectric layer on the first metal front dielectric layer by using a second CVD method. The metal front dielectric layer without depositing cave can be formed to improve the performance of device by changing the internal stress state of device. The first dielectric layer is deposited by HARP SACVD technics, thus reducing the depth width ratio in subsequent manufacture process. Then, the second dielectric layer is deposited by using HDPCVD, SACVD, PECVD or other traditional technics to complete the depositing of the dielectric layer, thereby ensuring that the subsequent work is identical with the prior technics, reducing the change to the prior technics to the lowest for the purpose of technics optimization, and reducing development cost.

Description

technical field [0001] The invention relates to the technical field of integrated circuit manufacturing, in particular to a method for forming a pre-metal dielectric layer and its structure. Background technique [0002] 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 device from impurity particles. The film deposition effect directly affects the performance of the device. [0003] With the gradual reduction of the size of semiconductor devices, the width of the slits to be filled during the deposition of the PMD layer is also getting smaller and smaller, and the aspect ratio is getting larger and larger. The ability to fill holes has become the optimization goal of the PMD layer deposition process. In the existing technology, high-density plasma chemical vapor deposition (HDPCVD) and subatmospheric pressure chemical vapor deposition (SACVD) p...

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Problems solved by technology

[0009] Obviously, although this method provides technical hints that can reduce the stress of the film layer, it cannot solve the seam filling problem

At the same time, the simple combination of the above-mentioned technical hints and the above-mentioned technical solution to solve the gap filling problem, that is, after the high-density plasma chemical vapor deposition of multiple deposition steps, and then perform an on-site steam generation process, can theoretically provide both guaranteed Seam filling quality, film deposition method that can reduce film layer stress again, but is not suitable for PMD deposition process, because the required temperature of described on-site vapor generation process is 700-1200 degrees Celsius, so high temperature will have formed device performance adversely affected

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