A burr-free photolithography method

Abstract

The invention relates to the technical field of semiconductor manufacturing and in particular relates to a burr-free photoetching method. The burr-free photoetching method comprises the following steps: S1, after pre-treating a wafer, coating the wafer with one layer of negative photoresist; carrying out selective exposure on the negative photoresist through a photoetching mask, wherein the exposure dosage of a photoetching machine is 100mj to 150mj and the focal distance deviation value is less than 1mu m; S2, carrying out first time of rotary covering and immersing type development on the exposed wafer, wherein the development time is 40s to 60s; S3, carrying out second time of rotary covering and immersing type development on the wafer after step S2, wherein the development time is 40sto 60s. According to properties of the negative photoresist, the negative photoresist can form a pattern better through limiting the exposure dosage, a exposure focal distance and time of 2 to 3 timesof the rotary covering and immersing type development, the pattern is wide in top and narrow in bottom and a lower layer of the pattern is concave inward; metal is not continuously distributed on thewhole photoresist in an evaporation process, so that a condition that the lower layer of the photoresist is stuck with the metal is avoided and a degummed metal layer is smooth and has no burrs; theelectrical property of appliances is improved and the yield of the appliances is improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a burr-free photolithography method. Background technique [0002] In the traditional lift-off photolithography process, a negative photoresist is coated on the surface of the wafer 1. The negative photoresist has the following characteristics in the optical exposure mode: the upper layer receives higher energy than the lower layer, and the upper layer is more exposed. The part of the negative photoresist is not easy to be developed, and the part with less exposure of the lower layer is easily dissolved in the developer, so that the image of the negative photoresist is an inverted trapezoid with a wide top and a narrow bottom. Such as Figure 1-2 As shown, the slope of the inverted trapezoidal angle is relatively large, and it is difficult to adjust. After metal evaporation, the metal formed on the side wall of the photoresist 2 is easy to adhere t...

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Problems solved by technology

like Figure 1-2 As shown, the slope of the inverted trapezoidal angle is relatively large, and it is difficult to adjust. After metal evaporation, the metal formed on the side wall of the photoresist 2 is easy to adhere to the metal in the filling area 3. When the glue is removed, the photoresist 2, the metal on the sidewall will be carried up together, causing a part of the metal in the filling area 3 that is adhered to the photoresist 2 sidewall metal to be taken away together, so that metal burrs appear in the remaining filling area 3 metal layer 4 5. It affects both the appearance and the product yield

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