Preparation method of indium column solder joint, chip substrate and chip

Abstract

The application discloses a method for preparing an indium column solder joint, a chip substrate and a chip. The method includes: coating a first photoresist layer on a substrate, and performing a first baking; coating a second photoresist layer on the first photoresist layer, and performing a second baking; performing underexposure on the photoresist layer, and performing a third baking; developing and fixing the second photoresist layer after the underexposure and third baking, so as to form an undercut structure on the second photoresist layer, The substrate has a photoresist structure; the substrate with the photoresist structure is flood-exposed, and the fourth baking is performed; after the flood exposure and the fourth baking, the first photoresist layer is etched to form A pattern-constrained layer; depositing indium material at the defined pattern position of the pattern-constrained layer to form an indium column solder joint; peeling off the first photoresist layer and the second photoresist layer from the substrate to obtain an indium column solder joint substrate. The present application can avoid the problem of lateral diffusion at the bottom of the indium column, and protect other positions of the substrate from being affected.

Description

technical field [0001] The embodiments of the present application relate to the fields of quantum technology and micro-nano processing technology, and in particular to a method for preparing indium pillar solder joints, a chip substrate and a chip. Background technique [0002] Indium column solder joint refers to the columnar indium metal deposited on a specific position of the substrate sample by means of evaporation coating, etc., and is used as a solder joint. [0003] The traditional process of preparing indium column solder joints is mainly based on the stripping process of a single layer of adhesive. Using a single photoresist, one exposure and development defines the indium column pattern, and then deposits metal indium and then peels off. This solution generally requires the thickness of the adhesive layer to be At least three times the height of the indium column, and because the glue sidewall in the pattern area will directly contact the deposited indium, the indi...

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Problems solved by technology

[0005] However, also due to the existence of the undercut structure, the bottom of the indium column will diffuse to the area of ​​the undercut structure during the indium plating process. This lateral diffusion will cause a thin layer of indium to be deposited on the substrate where there should not be indium. , thereby affecting structures or devices at other locations on the substrate

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