Double pattern forming method based on darc mask structure

Abstract

The invention relates to the technical field of microelectronics, in particular to a method for forming double patterning based on a DARC mask structure. Advanced patterning films are respectively adopted in two times of etching processes of a double patterning forming process to be used as the masks of the etching processes, patterns in a light resistor are transferred to grid polycrystalline silicon, and therefore the difference between the key sizes of the two times of etching processes is greatly improved to improve the uniformity of the key sizes, meanwhile, an APF replaces a traditional monox hard mask, a base layer structure ODL based on spin coating and a middle later structure SHB, process cost is saved, meanwhile, the technological processes with APFs as masks adopted by mature technological nodes of 40nm and more than 40nm are made to last to the technological nodes of 28 / 20nm and lower than 28 / 20nm, and therefore the maturity and the stability of the grid manufacturing processes of the technological nodes of 28 / 20nm and lower than 28 / 20nm are improved.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to a double pattern forming method based on a DARC mask structure. Background technique [0002] At present, at the technology node of 32nm and below, it is applied to the key-level lithography process. Since the resolution index required by it has exceeded the limit capability of the existing optical lithography platform, the industry has adopted a variety of technical solutions to solve the problem. According to the ITRS roadmap, technical solutions such as Double Patterning Technology (DPT for short), extreme ultraviolet technology (EUV), and electronic direct writing (EBL) have been placed high hopes by the industry. [0003] Among them, double patterning technology (DPT) is to decompose a set of high-density circuit graphics into two or more sets of low-density circuit diagrams, and then make photolithography plates separately, and complete the corresponding exposure a...

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Problems solved by technology

[0008] Among them, in the first etching process mentioned above, advanced patterning film (APF for short) is generally used as a soft mask (soft-mask), while ODL and SHB are used in the second etching process. As a soft mask, the critical dimension of the structure formed after the two etching processes is divided into two different levels, which makes it more difficult to control the critical dimension uniformity (CDU). If there is a defect in the critical dimension uniformity, it is extremely It is easy to cause the reduction of product performance and yield

[0009] In addition, ODL and SHB are new materials, and their process costs are relatively high, and they are not commonly used in the process of 40nm and above technology nodes; therefore, the above-mentioned new materials are introduced in the process of 28nm and below technology nodes Takes a lot of time and effort to evaluate and apply

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