Wafer arcing defect avoiding method

Abstract

The invention provides a wafer arcing defect avoiding method, which is characterized in that the edge of each metal layer is removed by a predetermined width by adopting edge washing treatment after each metal layer is formed, and the edge of an interlayer dielectric layer can surround the edge of the metal layer, so that the edge of each metal layer is avoided from being exposed, and the edge of each metal layer can be avoided from being directly contacted with plasmas in follow-up etching, thereby reducing accumulation of charge on the metal layers, avoiding generation of an arcing defect, and thus improving the yield of wafers.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for avoiding tip discharge defects on wafers. Background technique [0002] During the wafer preparation process, especially when the metal interconnection line is formed in the back-end process, the etching usually introduces the accumulation of charges. The consequence of excessive charge accumulation is that discharge occurs at the tip, resulting in tip discharge defects ( Arcing defect). The tip discharge defect is very fatal to the wafer, and the occurrence of a small area of ​​defecation will cause the entire wafer to be scrapped. [0003] After the metal interconnection is completed, a passivation layer (PAS) needs to be formed, and then the passivation layer is etched to expose the subsequent metal layer (such as an aluminum pad) that needs to be connected. The tip discharge defect usually occurs after etching the passivation layer. [0004] Specific...

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Problems solved by technology

[0005] However, since the photoresist is formed by spin coating, it is usually sprayed on the central area of ​​the wafer 20, and the wafer 20 rotates, and the photoresist is spin-coated from the central area of ​​the wafer 20 to the edge area of ​​the wafer 20 by centrifugal force. Such a formation method inevitably leads to thinner photoresist in the edge region of the wafer 20, and defects are prone to occur during etching, thereby exposing the edge of the metal layer 22 (such as figure 1 shown in the dashed box)

Since the edge of the metal layer 22 is flush with the edge surface of the interlayer dielectric layer 21 in the prior art, the interlayer dielectric layer 21 cannot cover the edge of the metal layer 22, and the etched plasma 30 will contact the metal layer 22. Contact occurs at the edge of the metal layer 22, and the charge will quickly accumulate on the metal layer 22

When the size of the etched window is within a certain range, due to the excessive accumulation of charges, which cannot be released, a discharge phenomenon will occur at the tip of the window, thereby forming a tip discharge defect 31, and then slowly diffuse from the edge of the wafer 20 to the The surface of the entire wafer 20 causes the formation of large-area tip discharge defects, resulting in the scrapping of the wafer 20

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