Cleaning technique of diode chip

Abstract

The invention provides a cleaning technique of a diode chip, and relates to an improvement of a cleaning liquid formula used in the cleaning technique, which can further reduce metal ions of the side surface of the chip, thus avoiding the chip from generating the phenomenon of creepage in working. The cleaning technique comprises the steps of mixed acid cleaning, double phosphorus cleaning and ammonia cleaning in sequence; when in ammonia cleaning, the cleaning liquid comprises ammonia water, water and hydrogen peroxide, the weight ratio of which is as follows: 1 part : 2-3.5 parts : 0.15-0.3 part. Compared with the original formula, the cleaning technique adds the hydrogen peroxide in ammonia cleaning liquid, feeds the obtained ammonia cleaning liquid downward onto an acid cleaning disc by an acid-feeding pipeline under the condition of being fully mixed; the acid liquid is over an upper nail head (equivalently to a clamping part of the upper end surface of the chip), thus leading the reaction to be full and further being capable of leading metal purities of the side surface of the chip to be removed more thoroughly; and the materials are more stable when being used under high temperature, thus reducing the instability of electric property of the materials due to larger surface leakage.

Description

technical field [0001] The invention relates to the cleaning process of semiconductor chips, in particular to the improvement of the cleaning liquid formula used in the cleaning process. Background technique [0002] The process of cleaning diode chips in the prior art is: mixed acid cleaning, double phosphorus cleaning and ammonia water cleaning, and there is a cleaning process with clear water after each cleaning process. Among them, the cleaning solution during mixed acid cleaning includes nitric acid, sulfuric acid, hydrofluoric acid and glacial acetic acid; the cleaning solution during dual phosphorus cleaning includes hydrogen peroxide and phosphoric acid, and the cleaning solution during ammonia cleaning is a diluted ammonia solution. [0003] The original ratio of ammonia water used is 3 parts of water and 1 part of ammonia water. The double phosphorus in the front mainly oxidizes the crystal grains, because after the mixed acid reaction, the elemental Si has a dangl...

AI Technical Summary

Problems solved by technology

in NH 3 This step is through NH 4 The complexation of + removes the metal ions further, but some metal atoms are not completely oxidized in the mixed acid and enter the third cleaning process, which cannot be removed during the ion oscillation process of the third cleaning

The removal effect of metal contamination on the grain surface during the whole process is not as good as we expected, which affects the electrical properties of pickling diodes