What is LED photoresist-EEWORLD

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Photoresist, also known as photoresist, is a photosensitive material used in many industrial processes, such as photolithography, which can engrave a pattern on the surface of a material.

There are two types of photoresists, positive photoresist and negative photoresist.

Positive photoresist is a type of photoresist, the part that is exposed to light will dissolve in the photoresist developer, while the part that is not exposed to light will not dissolve in the photoresist developer.

Negative photoresist is a type of photoresist, the part that is exposed to light will not dissolve in the photoresist developer, while the part that is not exposed to light will dissolve in the photoresist developer.

Positive photoresist and negative photoresist are mainly used in the lift-off process of metal electrode evaporation in LED chip manufacturing. Since the metal material used in LED electrodes is not easy to make circuit patterns through etching, a lift-off lithography process is used to obtain an overhanging photoresist pattern so that the metal will not be continuously covered on the photoresist during the evaporation process. The photoresist part not covered by the metal cloth is then lifted up by removing the photoresist to complete the pattern of the metal electrode.

Positive photoresist is commonly used in semiconductor processes. Under optical exposure, the upper layer of the photoresist receives higher energy than the lower layer of the photoresist, making most of the positive photoresist images narrow at the top and wide at the bottom. It is impossible to obtain an overhang pattern through a single exposure method. The imaging of the negative photoresist is exactly the opposite of the positive photoresist image, so negative photoresist is the best choice for the lift-off process.

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