Manufacturing method of flash memory structure with stress area
AssigneeEon Silicon Solution Inc.
InventorsYider Wu, Hung-Wei Chen
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Abstract
In a manufacturing method of a flash memory structure with a stress area, a better stress effect can be achieved by controlling the manufacturing process of a tunneling oxide layer formed in a gate structure and contacted with a silicon substrate, so that an L-shaped spacer (or a first stress area) and a contact etch stop layer (or a second stress area) of each L-shaped spacer are formed between two gate structures and aligned towards each other to enhance the carrier mobility of the gate structure, so as to achieve the effects of improving a read current, obtaining the required read current by using a lower read voltage, reducing the possibility of having a stress-induced leakage current, and enhancing the data preservation of the flash memory.
Claims7
A manufacturing method of a flash memory structure with a stress area, comprising the steps of:
- providing a silicon substrate;
- forming two gate structures on the silicon substrate, wherein each of the two gate structure comprises a tunneling oxide layer, a floating gate, a dielectric layer and a control gate sequentially disposed on the silicon substrate, and the tunneling oxide layer is formed and deposited at 750° C.˜800° C. and processed with a thermal annealing process at 750° C.˜800° C.;
- comprehensively depositing a first oxide layer, a second oxide layer and a third oxide layer sequentially;
- etching to expose a top of the two gate structures;
- removing the third oxide layer between the two gate structures;
- forming a metal silicide layer on each of the two gate structures;
- comprehensively depositing a contact etch stop layer;
- and
- performing an anisotropic etching to expose the silicon substrate disposed between the two gate structures, such that the second oxide layer becomes an L-shaped spacer aligned towards one another and disposed between the two gate structures to form a first stress area, and a contact etch stop layer on each L-shaped spacer become a second stress area.
Dependencies are inferred from the claim text.