Manufacturing method of superfine interval micro protruding point

Abstract

The invention discloses a manufacturing method of a superfine interval micro protruding point and belongs to the improved technology based on a traditional Damascus technology. The manufacturing method includes the steps that firstly, an electrolyte layer is deposited on a wafer, and holes penetrating through the electrolyte layer are etched; secondly, a metal seed layer is deposited on the surface of the wafer and in the holes, the surface of the wafer and the holes are filled with UBM metal and low-melting-point metal, CMP is performed on the metal on the surface of the wafer, the metal outside the hole is removed, and the surface of the metal in the holes especially the center area, namely the tin area is horizontal and free of concaved portions. The metal in the adjacent holes is isolated by electrolyte materials, the electrolyte materials on the periphery of the head portions of the metal in the holes are etched, so that the end faces of the head portions of the metal are higher than the peripheral electrolyte faces, and a micro protruding point structure with the low-melting-point metal wrapped by the UBM metal is formed. With the method, protruding point undercutting is avoided, the intervals of protruding points can be shrunk to several micron scales and even hundreds of nano scales, and a short circuit generated between a solder ball and an adjacent bonding pad in a traditional protruding point is avoided.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, relates to component processing in a semiconductor metal interconnection process, and in particular to a method for preparing micro-bumps with ultra-fine pitches. Background technique [0002] In recent years, the upgrading speed of new electronic consumer products represented by smart phones has been significantly accelerated, which puts forward higher and higher requirements for the development of integrated circuit technology. As a result, the feature size of integrated circuits continues to shrink, the integration of transistors per unit area is getting higher and higher, the interconnection density is also increasing, and the number of bumps per unit area of ​​the package is correspondingly increasing rapidly. [0003] With the advent of the era of 2.5D / 3D high-density interconnection, the importance of fine-pitch micro-bumps is becoming more and more obvious. For example, in the f...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the undercutting that occurs in the existing fine-pitch micro-bump preparation process, and the further reduction of the micro-bump spacing caused by the short circuit between the solder ball at the end of the micro-bump and the adjacent pad restricted question

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