Titanium seed etching liquid for wafer level package

Abstract

The invention discloses titanium seed etching liquid for wafer level package. The etching liquid is formed by mixing a component A and a component B according to the size proportion before use. The proportion of the component A and the component B is (0.8-1):1. The component A is hydrogen peroxide. The component B comprises, by concentration, 40-80 g / L of citric acid, 0.1-10 g / L of hydrogen peroxide stabilizer, 0.1-10 g / L of lateral erosion preventing agent, 30-90 g / L of dipotassium phosphate, 2-6 g / L of monopotassium phosphate and 0.1-10 g / L of surface activator. After being prepared according to the component proportion, the component B is mixed with the component A uniformly according to the proportion. After the component A and the component B are mixed uniformly, pH buffering liquid is added according to needs to adjust the pH value to be controlled within 8-9, and thus the titanium seed etching liquid is formed. The titanium seed etching liquid needs to be used when the temperature is between 30 DEG C and 60 DEG C. The titanium seed etching liquid has the characteristics of being stable in performance, suitable for super-thin line, and small in lateral erosion, and nearly having no corrosion to copper and aluminum.

Description

technical field [0001] The invention relates to the technical field of semiconductor wafer level packaging, in particular to a titanium seed etchant for wafer level packaging. Background technique [0002] With the continuous development of informatization and intelligence, the line width of chips continues to deepen in the direction of fine lines of 10nm, 8nm or even 6nm. The same is true in the field of wafer-level packaging. From the continuous refinement of the previous tens of micron circuits, the packaging of 1μm circuits has appeared, so higher requirements are put forward for related process technologies. [0003] Etching is the basis for making fine lines. In wafer-level packaging, a layer of titanium is generally vacuum sputtered as the bottom layer of copper lines to prevent diffusion between copper and silicon substrates. Wait until the copper lines are ready. Finally, the titanium layer outside the circuit is etched away to form an independent circuit. However...

AI Technical Summary

Problems solved by technology

However, while corroding the circuit, it will also be accompanied by the problem of side erosion. If the side erosion is too large, it is easy to hollow out the bottom of the line and cause the line to fall off.

Most of the current mass-produced titanium etching solutions contain fluorine, or the concentration and pH value are unstable, resulting in unstable etching rate, uneven etching and other defects.

Some foreign material suppliers have developed a potion that does not contain fluorine and has a stable etching rate. The side etching is only 0.3um and can perform titanium etching under ultra-fine lines. Although some problems have been solved, there are still problems such as high cost and short life.

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