Solution for nickel electroforming, electroforming method using solution and thin nickel plate manufactured by using method

Abstract

The invention provides a solution for nickel electroforming, an electroforming method using the solution and a thin nickel plate manufactured by using the method. The solution for nickel electroforming contains nickel aminosulfonate and nickel sulfate, and preferably also contains nickel bromide. The solution for nickel electroforming is adopted for electroforming in the method, and preferably a bidirectional pulse power supply is adopted as an electroforming power supply. The thin nickel plate has good thickness uniformity, low stress (pressure stress or tensile stress), smooth inner walls of micropores and no micro burrs or pin holes, and can be used for manufacturing an encapsulation template for transferring soldering paste during flip chip encapsulation.

Description

technical field [0001] The invention belongs to the technical field of material preparation technology, and relates to an electroforming solution, an electroforming method and a thin-layer nickel sheet prepared by the method, in particular to a method for transferring solder when making a flip-chip (flip-chip) package. Electroformed nickel sheets for packaging stencils for paste. Background technique [0002] Integrated circuit flip-chip packaging is an advanced chip interconnection technology and an ideal chip bonding technology. It has the advantages of small package area, high I / O density, good heat dissipation, high reliability and improved testability of bare chips. The key process of integrated circuit flip-chip packaging is to form bumps on the pads of the chip. Bump forming technologies include evaporation, sputtering, electroplating, and stencil printing. Among them, stencil printing has low cost, high efficiency, and can be used without Advantages such as lead so...

AI Technical Summary

Problems solved by technology

[0003] The current printing stencils are usually made by fine etching technology, but this technology cannot meet the requirements of stencil bump printing for chip-level packaging, and it mainly has the following defects:

[0005] (2) There is a problem of lateral corrosion;

[0006] (3) The etching technology is based on chemical dissolution, the surface of the formed opening is rough, and the hole wall is not smooth enough, which is not conducive to the printing of conductive materials;

[0007] (4) The hole size tolerance of the etching printing template is about 20 μm, resulting in uneven hole size;

[0008] (5) The uniformity of the hole size after etching is poor, and there will be a deviation of about 20 μm

In the case of using sodium chloride or nickel chloride, the compressive stress and tensile stress of the thin-layer nickel sheet cannot be balanced, and the prepared thin-layer nickel sheet has high stress, curling or warping.

[0020] Therefore, although the existing electroforming process can overcome the inherent shortcomings of the fine etching process to a certain extent, it is still difficult to overcome (especially difficult to overcome at the same time) the thin nickel sheet produced by electroforming also has problems such as thin Defects such as insufficient thickness uniformity of the layer nickel sheet, insufficient thickness uniformity around the micropore opening, and insufficient flatness after separation from the original mold

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