A wafer backside coating process that reduces the number of photoresist bubbles

Abstract

The invention discloses a wafer back coating process capable of reducing the number of photoresistive bubbles. The wafer back coating process capable of reducing the number of the photoresistive bubbles comprises the following steps: 1) coating the back side of the wafer with a diluent and wetting the back side of the wafer; 2) when the diluent still remains on the back side of the wafer, spray-coating the back side of the wafer with photoresist for the first time by using a dynamic spray-coating spray head; and 3) spray-coating the back side of the wafer with the photoresist for the second time by using the dynamic spray-coating spray head until preset spray-coating times are completed. Dirt and particles are removed from the coating surface of the wafer and the viscosity of the photoresist is reduced with the diluent, coating of the photoresist is conducted by using the dynamic spray-coating spray head, and the coating uniformity of the photoresist is improved, so the generating number of the bubbles in the wafer back coating process is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a wafer back coating process capable of reducing the number of photoresist bubbles. Background technique [0002] Among many wafer processing techniques, the coating process on the back of the wafer is an indispensable process, and photoresist bubbles are prone to occur in this process. Generally, the reasons for the generation of photoresist bubbles are as follows: Wafer coating There are dirt and particles on the surface of the cloth, which will cause photoresist bubbles after coating; the photoresist has a high viscosity, and it is easy to generate bubbles on the coating surface of the wafer during spraying; the spraying of the photoresist on the back of the wafer is static Spraying, that is, single-point spraying, is prone to single-point accumulation and air bubbles. Once bubbles are generated in the coating process on the back of the wafer, and the numb...

AI Technical Summary

Problems solved by technology

[0002] Among many wafer processing techniques, the coating process on the back of the wafer is an indispensable process, and photoresist bubbles are prone to occur in this process. Generally, the reasons for the generation of photoresist bubbles are as follows: Wafer coating There are dirt and particles on the surface of the cloth, which will cause photoresist bubbles after coating; the photoresist has a high viscosity, and it is easy to generate bubbles on the coating surface of the wafer during spraying; the spraying of the photoresist on the back of the wafer is static Spraying, that is, single-point spraying, is easy to cause single-point accumulation and air bubbles

Once bubbles are generated in the coating process on the back of the wafer, and the number of the bubbles is large, the following problems will occur: In the hole opening process on the back of the wafer, the existence of the bubbles may cause the bubbles to appear through holes after etching , causing some chips to be scrapped, and even affect the subsequent process; in the dicing process on the back of the wafer, if the air bubbles are connected to the dicing line, the etched shape of the dicing line will be abnormal, resulting in problems during cutting; if bubbles appear in the holes, it may be misetching of gold

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