Method for improving uniformity of electroplated metal film

Abstract

The invention relates to the technical field of semiconductors, and discloses a method for improving the uniformity of an electroplated metal film. The method comprises the following steps of S1, placing a wafer in a fixed electroplating cavity with the front surface facing downwards; S2, arranging a layer of rubber ring between two magnetic poles in the electroplating cavity, and arranging the rubber ring under the wafer, wherein the size of the rubber ring is smaller than the size of the wafer; S3, arranging two stirring devices between the two magnetic poles in the electroplating cavity, wherein the stirring devices are arranged below the rubber ring; and S4, starting a magnetic pump and the stirring devices, and leading electroplating metal liquid into the electroplating cavity through a pipeline for electroplating. According to the method, the uniformity of the metal film in the metal film process can be improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for improving the uniformity of an electroplated metal film. Background technique [0002] The metal thin film process is a commonly used and common process in the semiconductor industry. This process is to sputter and coat a layer of 400A TiW on the surface of the wafer through a sputtering machine. TiW provides a seed layer for the electroplating process to improve adhesion, and then Make a P electrode with a thickness of 3um by electroplating machine. At present, during electroplating, first place the wafer face down on a fixed cavity, press the back with a pillar, fix it on the cavity, and then use a magnetic pump to pull the electroplating metal solution through the pipeline into the electroplating cavity. Under the traction of the magnetic field on both sides of the cavity, it diffuses from the middle of the cavity to both sides, and flows back to the elect...

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Problems solved by technology

[0003] In the current electroplating method, due to the magnetic field adsorption on the edge of the cavity, the middle of the wafer is only coated by the inertia of the electroplating liquid rising upwards, so the result is that the metal film after each electroplating is always thick on both sides and thin in the middle, and the uniformity is generally less than 90. %, but generally in the metal thin film process with higher requirements, the uniformity is required to reach 95%-98%, but the existing electroplating method cannot achieve

[0004] The patent document with the application number CN201810597042.6 discloses a method to improve the uniformity of electroplating thick gold, by making an anode baffle around the gold plating tank and a movable anode baffle at the lower end and sealing it with a PP plate around the gold plating tank. 50mm side, to shield the current tip effect caused by the excessive amount of gold ions provided by the surrounding lotion; this technology controls the uniform distribution of the gold plating current through the size of the fixture and the splint method, which greatly ensures the power distribution between the edge of the plate and the plate to be plated Similarly, compared with the existing technology, this technology improves the uniformity of electroplating thickness, and improves the uniformity of gold plating from 60-70% of the industry's conventional level to 90-95%, but it still cannot reach the uniformity of 95%-98%

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