Method for improving appearance of phosphosilicate glass by virtue of high-density plasma chemical vapor deposition (HDP CVD)

Abstract

The invention discloses a method for improving the appearance of phosphosilicate glass by virtue of high-density plasma chemical vapor deposition (HDP CVD), comprising the following steps: (1) forming a gate electrode on a silicon substrate; (2) carrying out LDD (laser detector diode) injection and forming a side wall at the side wall of the gate electrode; (3) carrying out drain and source injection and fast thermal annealing; (4) adopting an HDP CVD process to deposit a phosphosilicate glass film, and introducing etching gas to react with the phosphosilicate glass in the process; and (5) carrying out self-aligned contact hole etching. In the method, the etching gas is introduced in the traditional HDP CVD process, so that the etching capability is improved, non-hole filling is guaranteed to be realized under a low-power radio-frequency bias voltage, and simultaneously, secondary sputtering in the deposition process is reduced, therefore, the width of a shell (flow pattern) with low P content formed on the surface of the phosphosilicate glass due to secondary sputtering is reduced, the appearance of the phosphosilicate glass film is improved, and the method is more beneficial to self-aligned contact hole etching.

Description

technical field [0001] The invention belongs to the field of semiconductor integrated circuit manufacturing, in particular to a high-density plasma chemical vapor deposition (HDP CVD) method, in particular to a method for improving the morphology of phosphosilicate glass deposited by high-density plasma chemical vapor deposition. Background technique [0002] Sub-atmospheric pressure chemical vapor deposition borophosphosilicate glass film (SACVD BPSG) is widely used before metal deposition as the insulating layer PMD (pre-metal dielectric) between the metal layer and the underlying polysilicon. Among them, P can absorb alkaline ions, and B can lower the glass transition temperature of the BPSG film, so that it can be reflowed and planarized at a lower temperature. However, as the feature size continues to decrease, the hole filling performance of SACVD BPSG cannot meet the requirements, that is, voids will appear during the hole filling process, which will cause a short cir...

AI Technical Summary

Problems solved by technology

Usually, when HDP technology is used to fill high-aspect ratio and small-sized channel structures (below 0.25 microns), in order to avoid voids during hole filling, high-power RF bias is required to increase the plasma physical bombardment etching rate. To obtain higher etching ability, thereby improving hole filling performance, but at the same time, high RF bias increases the bombardment intensity, which will also lead to aggravation of secondary sputtering, which also increases the width of flowerpattern, such as figure 1 shown

Due to the low P content in the flower pattern, the SAC etching rate decreases. If the flower pattern is too large, it will cause the etching stop phenomenon, and the contact hole 9 cannot be etched through, such as figure 2 shown

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