Method for forming void-free medium filling on graphical substrate

Abstract

The invention provides a method for forming medium filling on a graphical substrate and a corresponding liquid crystal on silicon (LCOS) product. The method for forming medium filling on the graphical substrate comprises the following steps of: in the first depositing process, depositing a first medium film on the graphical substrate; and in the second depositing process, motivating mixed gas to produce a high-density plasma and depositing a second medium film on the graphical substrate, wherein plasma-enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD) is adopted in the first depositing process and the thickness of the first medium film is more than 100A and less than 1,200A. Through the method provided by the invention, void-free medium filling can be realized in a high-aspect-ratio groove, particularly in a high-aspect-ratio groove of a large-sized graphic; and the method contributes to the realization of the high optical performance of the LCOS.

Description

technical field [0001] The present invention relates to a method for forming an insulating layer on a semiconductor material, in particular to dielectric filling on a patterned substrate. Background technique [0002] With the rapid development of semiconductor technology, the feature size of semiconductor devices has been continuously reduced and the device density has been continuously increased. Correspondingly, higher requirements have been placed on the chip manufacturing process. One of the challenging problems is that the insulating medium is in each thin film layer. Uniform and non-porous filling to provide sufficient and effective isolation protection, including shallow trench isolation (STI), pre-metal insulating layer (PMD), inter-metal insulating layer (IMD) and so on. Since the high-density plasma chemical vapor deposition (HDP CVD) process was adopted by advanced chip factories in the mid-1990s, it has rapidly developed due to its excellent hole filling ability...

AI Technical Summary

Problems solved by technology

[0007] However, the above-mentioned improvement methods are all aimed at the problems of pinch-off and voids generated in the middle of the trench during the filling process. With the continuous expansion of the application range of the HDP CVD process in the field of semiconductor manufacturing, a newly discovered problem is: When using HDP CVD to fill the grooves of large-scale graphics (the area occupied by the graphics is much larger than the area occupied by the grooves), especially when filling the grooves of Al thin film graphics of liquid crystal on silicon (LCOS) products, in the graphics Voids will be formed in the dielectric layer above the edge (as shown in Figure 2(a), (b)), and the resulting result is that the edge of the Al thin film pattern is due to the subsequent chemical mechanical polishing (CMP) and etching process. are over-etched to form defects (such as image 3 shown)

Since the Al thin film pattern is used as a reflective layer in LCOS products, more defects at the edge of the Al thin film will seriously affect the optical performance of the LCOS product and reduce the product yield (yield)

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