PIP capacitor and forming method

Abstract

The invention provides a PIP capacitor and a forming method thereof. The method comprises the steps of providing a substrate which comprises a CELL region and a PIP region, forming a shallow trench isolation structure in the substrate of the PIP region, forming a plurality of spaced gate structures on the substrate of the CELL region by using a photomask of the gate structures, forming a plurality of spaced pseudo gate structures on the shallow trench isolation structure by using a photomask of the gate structures, exposing the surfaces of the shallow trench isolation structure among the plurality of pseudo gate structures, and enabling the longitudinal sections of the pseudo gate structures to be square, sequentially forming word line polycrystalline silicon and an insulating layer which are both in a sine wave shape on the dummy gate structure, and forming grid polycrystalline silicon on the insulating layer. The insulating layer is in a fluctuating sine wave shape, and the relative area between the word line polycrystalline silicon and the gate polycrystalline silicon is increased, so that the capacitance value of the PIP capacitor is increased. Moreover, the pseudo gate structure and the gate structure are formed at the same time, so that additional photomasks and process steps are not needed.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a PIP capacitor and a forming method. Background technique [0002] Up to now, semiconductor integrated circuit design has a variety of capacitors to choose from, including MOS (metal-oxide-semiconductor) capacitors, PIP (polysilicon-insulator-polysilicon) capacitors, MIM (metal-insulator-metal) capacitors, MOM ( metal-oxide-metal) capacitors, etc. In order to meet customers' requirements for capacitance characteristics and low cost, PIP capacitors have been widely used. [0003] Please refer to figure 1 , the prior art method for forming a PIP capacitor is to form a shallow trench isolation structure 120 in the substrate 110, and form a word line polysilicon 130 on the shallow trench isolation structure 120 as a lower-level plate of the PIP capacitor; on the word line polysilicon 130 The oxide layer 140 is formed as the insulating layer of the PIP capacitor; the gate p...

AI Technical Summary

Problems solved by technology

However, as the size of electronic products decreases, the size of the PIP capacitor also needs to be reduced, resulting in a reduction in the area of ​​the upper plate and the lower plate of the PIP capacitor, and finally the capacitance value of the manufactured PIP capacitor is reduced.

Affects the demand for high-capacitance PIP capacitors in electronic devices

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