Method for forming flash memory

Abstract

The invention discloses a method for forming a flash memory. The method comprises the following steps of: forming a tunneling oxide layer on a semiconductor substrate; forming a control gate and a floating gate on the annealed tunneling oxide layer in turn; performing a cleaning process to generate organic polymer on the surface of the semiconductor substrate; performing plasma treatment to remove the organic polymer; forming photoresist layers on the semiconductor substrate and the gate and defining a source / drain pattern; implanting ions into the semiconductor substrate on the two sides of the gate by taking the photoresist layers as masks so as to form a source / drain; and performing metal wiring to form the flash memory. In the method, the organic polymer is treated by a plasma, so that particles with silanol structures, which are produced in the cleaning process, can be cleaned; and holes are prevented from being formed in the subsequently formed photoresist layer, and the electrical property of a semiconductor device is effectively improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a flash memory. Background technique [0002] In the manufacturing process of semiconductor devices, the pretreatment of the wafer surface is one of the most important and frequent steps. Generally speaking, during the process of wafer storage, loading and unloading, and the entire manufacturing process of semiconductor devices, contaminants such as particulate matter, metal ions, organic matter, etc. are usually left on the wafer. Therefore, pretreatment steps such as cleaning are required to avoid residual traces of ions and metals on the wafer. [0003] Different cleaning methods are required for different pollutants. Organic impurity pollution can be removed through the dissolution of organic solvents combined with ultrasonic cleaning technology; particle pollution can be removed by physical methods such as mechanical scrubbing or ul...

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Problems solved by technology

[0008] Currently, after etching to form a stacked gate structure, SC1 cleaning solution or SPM cleaning solution is usually used for cleaning to remove particles; however, during the cleaning process, the hydroxide ions in the cleaning solution will interact with the semiconductor substrate Silicon reacts to form particles 130 with a silanolane structure; furthermore, when the photoresist layer is subsequently formed, after the baking process, the particles will expand to form cavities 130a, resulting in a decrease in the electrical performance of the formed semiconductor device

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