Epitaxial filling method of deep trench

Abstract

The invention discloses an epitaxial filling method of a deep trench. When epitaxial filling is carried out on a deep trench, first-time epitaxial filling is carried out till a mouth edge of the deeptrench, and the trench is not filled completely; and chemical mechanical grinding is carried out, the surface of a wafer is ground to be flat, the epitaxy in the trench is etched, and then second-timeepitaxial filling is carried out until the epitaxy in the trench is filled completely. According to the epitaxial filling method, the epitaxial filling of the deep trench is carried out by two steps,first-step filling is carried out and then the upper layer part with a defect is etched and removed, and then second-step epitaxial filling is carried out. When the second-step epitaxial filling is carried out, the depth-to-width ratio of the trench is improved equally, so that epitaxial filling reaches a good effect, the filling defect is eliminated, and the device performance is improved.

Description

Technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a deep trench epitaxial filling method in a super junction device process. Background technique [0002] In the super junction project, the fourth generation process is based on the third generation. The deep groove is optimized from the original 88.6 degree to 90 degree, and the pitch (cell size) is reduced from the original 4:5 to 2:3, and the groove is in the CD plane. The range is also significantly reduced, and device performance is therefore significantly improved. On the other hand, the optimization of trench morphology and size will greatly increase the difficulty of epitaxial filling. [0003] When the deep trench is epitaxially filled, monocrystalline silicon grows along the sidewall and bottom of the trench at the same time, forming such figure 1 Shown morphology. Continue to grow when figure 1 When the central position of the middle groove is narrowly stitched, d...

AI Technical Summary

Problems solved by technology

This is because the width of the trench itself is relatively narrow (only 2um), and it is filled to such as figure 1 Morphology, when a narrow slit is formed, there are obvious corners at the top of both sides of the slit. Near this corner, the crystal orientation of the filled epitaxial layer is inconsistent with other plane positions. When the slit is merged, it is easy to cause Mismatch produces dislocation

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