Method of making electrical test structure for detecting vias

Abstract

The invention provides a manufacturing method of an electric testing structure for detecting through holes. When a layout is designed, a through hole graph is connected with the overlapping area of a plurality of adjacent metal graphs in an intersection mode, the through hole graph size is larger than the target through hole size, a through hole pattern subsequently formed in optical resist is enabled to be larger than a target through hole graph in size, and therefore a photo-etched technical window is widened, and the photoetching resolution and the photoetching precision are improved; besides, a hard mask layer serves as a mask, and an upper layer metal pattern in the hard mask layer is etched into an etched barrier layer and an upper dielectric layer so that a target through hole pattern can be formed; the target through hole size is determined by the size of the upper metal pattern in the hard mask layer and the through hole size jointly and not determined by the size of the through hole graph in the optical resist, and therefore target through holes with smaller intervals can be obtained without splitting the through hole graph, the technical window is widened, and the photoetching resolution ratio is increased.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a preparation method of an electrical test structure for detecting through-hole resistance and electric leakage. Background technique [0002] According to Moore's law, the critical dimensions of semiconductor devices continue to shrink, and the line width of interconnect lines also continues to decrease. In order to obtain lower resistance and capacitance in the dielectric film of interconnect lines, the process generation of 0.13um and below is gradually changed from Copper interconnects have replaced aluminum interconnects. Due to the difficulty of dry etching metal copper, a dual damascene process is generally used to form copper interconnects and vias. [0003] In the copper interconnection process, resistance and leakage are the most concerned parts of the process. The size of the resistance affects the speed of the device, and the size of the leakage affects the re...

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Problems solved by technology

[0004] Existing electrical test structures for detecting through-hole resistance and leakage usually include upper metal, through-holes and lower-layer metal; The critical dimensions between the patterns in the adopted layout have gradually reached the limit of single lithography technology, and the process window of lithography is getting smaller and smaller, which will lead to higher and higher requirements for lithography resolution; in order to improve the photolithography To increase the engraving resolution, graphics splitting and splicing technology can be used to form small-sized graphics by splicing large-sized graphics; however, multi-layer graphics need to be split multiple times, and the application of multiple graphics splitting and splicing technology will undoubtedly increase The complexity and cost of the process are reduced; for example, in the preparation of electrical test structures, not only the upper and lower metal patterns need to be split, but also the through-hole patterns need to be split

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