Test structure, preparation method and test method for short-circuit defect of shared contact hole

Abstract

The invention provides a test structure for the short-circuit defect of a shared contact hole, a preparation method and a test method. The test structure has a first conductive type transistor. The first conductive type transistor comprises an active region, a first gate and a second gate located on the active region, a first gate-source shared contact hole located on the first gate and a second gate-source shared contact hole located on one end of the second gate. The bottom of one end of the second gate is not provided with the active region. The first gate-source shared contact hole is connected with one end of the first gate and the active region. The second gate-source shared contact hole is only connected with one end of the second gate. The bottom of the second gate-source shared contact hole is not connected with the active region. According to the test structure of the invention, whether the second gate-source shared contact hole is short-circuited or not can be intuitively judged. Therefore, the monitoring over the flatness, the process and the equipment of a subsequent process window is facilitated.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a test structure and a test method for a short-circuit defect of a shared contact hole. Background technique [0002] With the development of integrated circuit technology, the size of semiconductor technology is getting smaller and more complex. The process window of many process integrations is getting smaller and smaller, such as the short circuit between contact holes and polysilicon, which is affected by alignment accuracy and critical dimensions of contact holes and polysilicon, and is one of the difficult issues in the development of processes below 28nm. [0003] Such as Figures 1 to 5 As shown, among them, figure 1 It is a schematic diagram of wafer yield test, figure 2 A scanning electron microscope picture of a short circuit between the existing gate-source shared contact hole and the gate, image 3 A scanning electron microscope picture of th...

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Problems solved by technology

However, for this electrical failure problem, optical inspection is not accurate enough for on-line monitoring, and since the shared contact hole is in a conventional SRAM structure, one end of it will be connected to polysilicon, when the other end is shorted to another polysilicon , there will be no change in potential, so it cannot be monitored for electrical defects, such as Figure 5 shown

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