A method of chemical mechanical polishing

Abstract

The invention discloses a chemical mechanical polishing method, which comprises steps: (a) a wafer is provided; (b) polishing slurry is provided on the surface of the wafer, and high lower pressure polishing and first low lower pressure polishing are executed sequentially; (c) main cleaning is carried out to remove part of the polishing slurry and residue, and the remaining polishing slurry is uniformly distributed; (d) second low lower pressure polishing is executed, coating of the polishing slurry does not happen, defects on the water are removed through polishing, and the remaining polishing slurry is removed. Through adding of the main cleaning step, after high lower pressure polishing and low lower pressure polishing, the wafer can has a flat surface, due to the low lower pressure polishing step executed finally, the remaining polishing slurry on the wafer can be removed, the polishing slurry remaining problem can be solved, the wafer can be completely cleaned, and the yield of the wafer is further improved.

Description

technical field [0001] The invention relates to a semiconductor manufacturing process, in particular to a chemical mechanical grinding method. Background technique [0002] With the rapid development of portable electronic devices (such as mobile phones, digital cameras, MP3 players, and PDAs, etc.), the requirements for data storage are getting higher and higher. Non-volatile memory has become the most important storage component in these devices because of its ability to save data even when power is off. Among them, because flash memory (flash memory) can achieve a high chip storage density, and no new materials are introduced , The manufacturing process is compatible, therefore, it can be more easily and reliably integrated into own digital and analog circuits. [0003] Floating gate structure memory is one of the important flash memory devices, and it is a mainstream memory type that is widely used and generally recognized, and is widely used in the electronics and comp...

AI Technical Summary

Problems solved by technology

[0004] Due to the special pattern of the embedded memory and the distribution problem, the CMP slurry (slurry) is unevenly distributed during the CMP process, causing polysilicon residue when the polishing pad (pad) grinds the control gate (multi-choice polysilicon) layer , the main defect is a region of small size, which affects the yield of the product

[0005] In the prior art, the method of CMP in the floating gate preparation process is as follows: Figure 1a-1c As shown, wherein a semiconductor substrate 101 is provided to form a component pattern 10 in the semiconductor substrate, and then a floating gate layer 102 and a plasma oxide layer 103 are formed on the components, and then the plasma oxide A CMP slurry 104 is formed on the layer 103, wherein due to the unevenness of the surface of the plasma oxide layer 103, the slurry 104 formed on the plasma oxide layer 103 is not uniform, wherein in the small grooves The slurry is difficult to enter, so the slurry is less distributed, and the slurry is distributed more in the grooves and protrusions with larger opening sizes, and then high downforce CMP and low downforce (low down force) CMP, such as Figure 1c As shown in the figure, it can be seen from the figure that on the left side of the device, due to the small spacing between the component patterns 10, the distribution of the polishing liquid is less, resulting in a certain residue of the polysilicon layer, causing defects

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