Embedded flash memory and manufacturing method thereof

Abstract

The invention discloses an embedded flash memory and a manufacturing method thereof. The manufacturing method comprises the steps of providing a semiconductor substrate on which a plurality of floating gates are formed, wherein an insulating material layer is formed between two adjacent floating gates; performing first etching on the insulating material layer for forming grooves; forming a compensating layer on the floating gates and the insulating material layer after first etching; etching the compensating layer until the upper surface of each floating gate is exposed, and performing second etching on the insulating material layer after first etching,, thereby forming an insulating structure, wherein the upper surface of the insulating structure is bowl-shaped; and successively forming a dielectric layer and a control gate on the insulating structure and the floating gate. According to the manufacturing method of the invention, under a precondition that high coupling ratio and high data storage performance are ensured, a breakdown voltage between the control gate and an active region is increased. Furthermore, because the breakdown voltage is increased, the distance between the control gate and the active region can be reduced approximately, thereby improving the coupling ratio and the data storage performance to a certain extent.

Description

technical field [0001] The present invention relates to the technical field of memory devices, in particular to a flash memory with an embedded gate structure and a manufacturing method thereof. Background technique [0002] Embedded-Flash (Embedded-Flash) technology embeds flash memory circuits into standard logic or mixed circuit technology. Due to the advantages of efficient integration, it has been widely used in various consumer electronics products, industrial applications, personal computers and wired communication equipment. . [0003] A typical embedded flash memory includes a transistor, which has a two-gate structure. Such as figure 1 As shown, the first gate structure generally includes a floating gate 150 that stores charge. The floating gate 150 also acts as a transistor gate, forming a conductive path between the source / drain regions of the substrate 110 . Control gate 190 as a second gate structure is generally located adjacent to floating gate 150 but is...

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Problems solved by technology

[0005] However, in the process of making the embedded flash memory, it is easy to remove part of the isolation structure 140 during the process of removing the nitride on both sides of the isolation structure (such as shallow trench isolation) 140, resulting in the part of the isolation structure 140 located on the substrate 110 becoming deformed. narrow

The consequence of this is that, if figure 2 As shown, the distance D' between the control gate 190 and the surface of the active region at the edge is shortened

This shortening of the distance does not produce any contribution to the coupling rate and data retention performance, but will seriously affect the breakdown between the control gate 190 and the active region

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