Polymer cleaning method for etching cavity

Abstract

The invention discloses a polymer cleaning method for an etching cavity. The method comprises the following steps that: step 1, the light transmittance of a last batch of wafers of the etching cavityis collected; step 2, the parameters of the self-cleaning process of the etching cavity are calculated according to the collected light transmittance; step 3, the self-cleaning process of the etchingcavity is performed according to the set parameters; and step 4, the etching process of a next batch of wafers is performed. With the method of the invention adopted, the polymers of the etching cavity can be well cleaned, and the accumulation of the polymers in the etching cavity can be eliminated, and thus, a "first wafer effect" can be eliminated, and the yield of products can be improved.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit manufacturing method, in particular to a polymer cleaning method for etching a cavity. Background technique [0002] As integrated circuit technology enters the era of ultra-large-scale integrated circuits, the process size of integrated circuits is developing towards 65nm and smaller structures, and at the same time, higher and more detailed technical requirements are put forward for wafer manufacturing processes. [0003] In the large-scale wafer manufacturing process, dry etching is required. The dry etching process needs to be carried out in the etching chamber. As the number of wafer processing continues to increase, the internal environment of the etching chamber will change accordingly. Changes occur, that is, the previous piece or batch of wafers has a certain degree of influence on the next piece or batch of wafers, which has a memory effect. Wherein, a wafer usually refers to a sili...

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Problems solved by technology

[0005] The waferless self-cleaning process is very effective in producing the same amount of polymer cleaning effect for each batch of operating wafers. As long as a sufficient cleaning time is set, the cleaning between batches of wafers can be completed, but for each batch of wafers There are many disadvantages in this method of cleaning that produces different amounts of polymers. If the cleaning is insufficient, the polymers will continue to accumulate. When the accumulation reaches a certain level, the source of defects will occur. If the amount of cleaning is too large, it will cause continuous erosion of the plasma. To the inner wall parts of the cavity, the defect source will also be sputtered out while damaging the parts

[0006] In the actual plasma etching process, due to design requirements, the same etching program will be used to etch different lithographic light transmittance layers. The light transmittance refers to the light transmittance of the photoresist of the corresponding photoresist layer during exposure. When the material of the photoresist is the same, the light transmittance of the corresponding exposure area of ​​the photoresist will also be different. The area of ​​the process photoresist is exposed, and due to the difference in the light transmittance of the lithography, the exposed etching area is different during the etching process, and the amount of polymer produced will also be different, which makes the existing etching chamber Polymer buildup prone to polymer cleaning methods

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