Method of forming a semiconductor device

Abstract

The present invention provides a method for forming a semiconductor device. In the method, copper deposition includes a step of depositing the bottom of the groove, a step of filling the groove to fill at least the first groove, and a step of planar deposition, and the step of filling the groove Compared to the deposition step at the bottom of the groove, the concentration of the accelerator is reduced and the concentration of the inhibitor is increased. In the present invention, when the deposition step at the bottom of the groove is performed, the copper deposition at the bottom of the groove is quickly completed by using an accelerator, and when the filling step of the groove is performed subsequently, the concentration of the accelerator decreases and the concentration of the inhibitor increases, so as to reduce the amount of the groove. The filling speed can avoid the problem of over-plating caused by the rapid filling of the groove, and can reduce the convex height of the surface after the groove is filled. Follow-up deposition steps can further reduce the thickness difference of electroplating copper in different areas, thereby improving the appearance of chemical mechanical polishing. copper residues and copper butterfly defects, improve product reliability and prolong product life.

Description

technical field [0001] The present invention relates to the technical field of integrated circuit manufacturing, in particular to a method for forming a semiconductor device. Background technique [0002] In the semiconductor manufacturing process, a copper electroplating process is usually used for interconnection, that is, a groove is formed first, and then copper is electroplated in the groove. The copper electroplating process fills the grooves with the bottom up growing. Due to the use of accelerators, the growth rate at the bottom of the grooves is greater than that at the sidewalls and openings. When the grooves are filled, copper will continue to rush up and grow. The copper thickness of the final groove area is higher than that of the open area, and the phenomenon of over-plating occurs. With the advancement of the process node, the line width gradually shrinks, and the over-plating phenomenon becomes more and more obvious. [0003] Since copper electroplating is ...

AI Technical Summary

Problems solved by technology

[0003] Because electroplating copper is affected by the pattern, there is usually obvious overplating phenomenon in the area with small line width and high pattern density, and there are great differences in the height and fluctuation of the copper film, which often increases the difficulty of copper chemical mechanical polishing (CMP)

In order to achieve the purpose of comprehensive planarization, copper residues will appear in areas with high pattern density, which will easily lead to short circuit of metal lines

In order to solve the problem of copper residue, after grinding, copper butterfly-shaped depressions will appear in large open areas, which will cause the next layer of metal wires to break

[0004] For the overplating phenomenon, the current way to improve it is to use more advanced organic additives at a high cost, but the improvement effect is limited, especially for high-density pattern areas.

Images