Preparation method of indium column welding spot, chip substrate and chip

Abstract

The invention discloses a preparation method of an indium column welding spot, a chip substrate and a chip. The method comprises the following steps: coating the substrate with a first photoresist layer, and carrying out first baking; coating the first photoresist layer with a second photoresist layer, and carrying out second baking; carrying out under-exposure on the second photoresist layer, and carrying out third baking; developing and fixing the second photoresist layer after underexposure and third baking to form an undercut structure on the second photoresist layer, wherein the substrate has a photoresist structure; carrying out extensive exposure on the substrate with the photoresist structure, and carrying out fourth baking; etching the first photoresist layer to form a pattern limiting layer after extensive exposure and fourth baking; depositing an indium material at a defined pattern position of the pattern limiting layer to form an indium column welding spot; and stripping the first photoresist layer and the second photoresist layer from the substrate to obtain the substrate with the indium column welding spots. According to the invention, the problem of lateral diffusion at the bottom of the indium column can be avoided, and other positions of the substrate are protected from being influenced.

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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