CN111092011B - A treatment method for improving surface contamination of LED chips - Google Patents

Abstract

The invention relates to a treatment method for improving surface pollution of an LED chip, belonging to the technical field of LED chips, comprising the steps of (1) cleaning and brushing the chip in absolute ethyl alcohol solution and deionized water in sequence, (2) cleaning and brushing the chip in acetic acid solution and deionized water in sequence; (3) placing the chip in a mixed solution consisting of acid, deionized water and fluoride for cleaning, and then taking out and placing the chip under the deionized water for rinsing; (4) placing the chip in a cleaning machine for high-pressure deionized water cleaning and nitrogen blow-drying; (5) and taking out the chip, placing the chip on a heating table, and baking to thoroughly remove water vapor. The method has the advantages of low raw material consumption, simple steps, simple and convenient operation and low treatment cost, can effectively remove surface abnormalities such as pollution, residual reagent, roughness and the like on the surface of the chip, and improves the quality and yield of the chip.

Description

A treatment method for improving surface contamination of LED chips

technical field

The invention relates to a treatment method for improving the surface pollution of LED chips, belonging to the technical field of LED chips.

Background technique

LED lighting technology has developed very rapidly. Since the 1960s, relevant statistics show that the cost of LEDs has dropped tenfold every ten years, while the luminous efficiency has increased tenfold every ten years. Building decoration, landscape, outdoor display, backlight, toys, clothing and other aspects are accepted by people. At the same time, LED technology is constantly being upgraded and innovated to meet the different needs of human production and life.

In the LED production process, the production of LED chips is an important factor affecting product cost, indicators and sales. As we all know, the production of LED chips needs to go through multiple steps such as metal coating, pattern production, substrate thinning, chip cutting, testing, packaging, etc. Any problems in any step will directly affect the final quality of the chip. Downshifting, severe direct scrapping, ultimately affects product cost and benefit. Therefore, only strict control during the production process of the chip can effectively ensure the final quality of the chip. Even so, the abnormal appearance of the chip is more or less unavoidable, mainly because of equipment, technology, man-made, environment, raw materials, etc. The factors cannot be precisely controlled. Even if it is done, the related capital investment will greatly increase the product cost, which is still not beneficial to the final product benefit.

The common surface abnormalities in the LED chip manufacturing process are mainly pollution, electrode loss, difficult wire bonding, electrode corrosion, and poor appearance. important association. At present, the metal electrode material on the surface of the LED chip electrode in the industry is mainly gold or aluminum. Compared with the aluminum electrode, the gold electrode is better in stability and quality, but the cost is high. Therefore, most LED manufacturers still choose the aluminum electrode as the electrode material. , It is susceptible to acid and alkali corrosion, and is more sensitive to the acid and alkali reaction of the solution and the environment. This is the main reason why the aluminum electrode is prone to surface abnormalities. Of course, it is also related to the surface roughness of the electrode evaporation. In addition, during the normal production process of the chip, due to the multi-step organic and inorganic reagents and hot nitrogen drying operations, the surface of the chip is prone to contamination such as reagent residues, which cannot be effectively removed by ordinary secondary cleaning. Conventional methods for dealing with surface contamination of LED chips are mainly to remove surface contaminants by cleaning with organic solvents or physically bombarding the chip surface with a gluer, etching machine, etc., but the effect is limited and often brings new quality problems. Most of the final chips cannot escape the result of quality downgrade, and the cost and efficiency of the processing method are also a loss.

At present, there is no report on the improvement of surface abnormalities such as contamination, roughness, and difficult-to-bond lines of LED chips.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention provides a simple and easy treatment method for improving the surface contamination of LED chips, which is simple and easy to implement, improves product yield and benefits, and only requires conventional inorganic solutions, wool brushes, and cleaning machines. It can effectively improve the organic or inorganic residual glue, residual pollutants, oxide layer, etc. on the conventional chip surface to meet the appearance requirements of the product, without affecting the subsequent product quality and sales, and ensuring product benefits.

The technical scheme of the present invention is as follows:

A treatment method for improving surface contamination of LED chips, comprising the following steps:

(1) Place the chip in anhydrous ethanol solution for cleaning, then take out and use a wool brush to dip in anhydrous ethanol to gently brush the surface of the chip, and then place the chip in deionized water to rinse;

(2) place the chip in the acetic acid aqueous solution for cleaning, then take out and use a wool brush to dip the acetic acid aqueous solution to gently brush the surface of the chip, and then place the chip in deionized water to rinse;

(3) The chip is placed in the mixed solution of acid, deionized water, fluoride and washed, and then quickly taken out and placed in deionized water to rinse; the acid is acetic acid, formic acid, hydrosulfuric acid, oxalic acid, metaaluminate , one or more of hypochlorous acid and hydrofluoric acid, and the fluoride is one or more of ammonium fluoride, sodium fluoride, sodium bifluoride, and aluminum fluoride;

(4) Place the chip in a cleaning machine at 1000-5000 rpm for high-pressure deionized water cleaning and nitrogen drying;

(5) Take out the chip and place it on the heating table to bake to completely remove the water vapor;

(6) Check the improvement effect of the chip surface contamination under the microscope. If the treatment is completely finished, if the improvement still needs to be improved, go back to step (1).

Preferably according to the present invention, in step (1), the chip is placed in an anhydrous ethanol solution for cleaning for 10-30s; the entire surface of the chip is scrubbed 1-6 times with a brush; then the chip is placed in deionized water for 10-30s rinse .

Further preferably, in step (1), the absolute ethanol is analytically pure, with a purity of ≥99.7%; the conductivity of the deionized water is ≤0.2 μs/cm.

Preferably according to the present invention, in step (2), the volume ratio of the acetic acid aqueous solution is 2%-10%; cleaning in the acetic acid aqueous solution for 1-5min; using a brush to brush the entire chip surface 1-6 times; then placing the chip on the Rinse with deionized water for 10-30s.

Further preferably, in step (2), the acetic acid in the acetic acid aqueous solution is analytically pure, and the purity is more than 99%.

Preferably according to the present invention, in step (3), the weight ratios of acid, fluoride and deionized water are respectively 1%-20% of acid, 1%-20% of fluoride, and 60%-98% of deionized water.

Further preferably, in step (3), the acetic acid, formic acid, hydrosulfuric acid, oxalic acid, metaaluminate, hypochlorous acid, ammonium fluoride, sodium fluoride, sodium hydrogen fluoride, aluminum fluoride, and hydrofluoric acid are of analytical grade. , purity ≥95%.

Further preferably, in step (3), the chip is placed in the mixed solution for cleaning for 1-30s, and then placed in deionized water for washing for 30-60s.

Preferably according to the present invention, in step (4), the purity of the nitrogen gas is greater than 99.9%.

According to a preferred embodiment of the present invention, in step (5), the chip is placed on a heating table at 40-80° C. to bake for 5-30 minutes.

The beneficial effects of the present invention are:

After the conventional organic matter on the surface is removed by the invention, the surface of the aluminum electrode is directly corroded by an acid solution, and the contaminants on the surface of the chip electrode are removed by combining with a brush. Baking after rinsing is mainly used to improve the phenomenon that the surface of the aluminum electrode is prone to oxidation because the surface is relatively active after being treated with an acidic solution. By baking, the water vapor can be quickly removed, the surface activity is reduced, and surface abnormalities are avoided.

The invention has low consumption of raw materials, low cost, simple steps and simple operation, effectively improves various contaminations on the chip surface, residual reagents, rough electrodes, etc., improves product yield, and ensures the benefits of subsequent products.

Description of drawings

FIG. 1 is a schematic diagram of the same chip surface before contamination treatment in Example 1 of the present invention.

FIG. 2 is a schematic diagram of the same chip surface after contamination treatment in Example 1 of the present invention.

Detailed ways

The present invention will be further described below with reference to the embodiments and the accompanying drawings, but is not limited thereto.

Example 1

A treatment method for improving surface contamination of LED chips, comprising the following steps:

(1) Clean the chip in 99.7% pure ethanol solution for 15s, then take it out and use a wool brush dipped in absolute ethanol to gently brush the chip surface, brush the entire chip surface 3 times, and then place the chip on the Rinse with deionized water for 10s with conductivity of 0.2μs/cm;

(2) Place the chip in an aqueous solution of acetic acid (purity 99.6%) with a volume ratio of 5% for 3 minutes, then take it out and use a wool brush dipped in the acetic acid aqueous solution to gently brush the surface of the chip, and brush the entire chip surface 3 times, then Rinse the chip in deionized water for 12s;

(3) Place the chip in a mixed solution consisting of acetic acid (purity 96%), hypochlorous acid (purity 97%), ammonium fluoride (purity 97%), and deionized water (weight ratios are 2% acetic acid, 2% Chloric acid 1%, ammonium fluoride 2%, deionized water 95%) for 3s, then quickly take it out and rinse with deionized water for 50s;

(4) The chip is placed in a cleaning machine at 3000 rpm for high-pressure deionized water cleaning and nitrogen (purity 99.99%) drying;

(5) Take the chip out and bake it on a heating table at 60°C for 15 minutes to completely remove the water vapor;

(6) The contamination of the chip surface is effectively improved under the microscope. As shown in Figure 2, the contamination of the chip surface is improved. Using this treatment method, the qualified rate of the contaminated chip can reach more than 95%.

Example 2

A treatment method for improving surface contamination of LED chips, comprising the following steps:

(1) Clean the chip in 99.8% pure ethanol solution for 12s, then take it out and use a wool brush dipped in absolute ethanol to gently brush the chip surface, brush the entire chip surface twice, and then place the chip on the Rinse in deionized water for 14s with conductivity of 0.18μs/cm;

(2) Place the chip in an aqueous solution of acetic acid (purity 99.7%) with a volume ratio of 3% for 4 minutes, then take it out and use a wool brush dipped in the acetic acid aqueous solution to gently brush the surface of the chip. The entire chip surface is brushed 4 times, and then Rinse the chip in deionized water for 20s;

(3) The chip was placed in a mixed solution composed of oxalic acid (purity 99%), hydrosulfuric acid (purity 96%), sodium fluoride (purity 98%), and deionized water (weight ratios were 6% oxalic acid, 6% hydrosulfuric acid, respectively) 5%, sodium fluoride 8%, deionized water 81%) for 3s, then quickly take it out and rinse with deionized water for 40s;

(4) The chip is placed in a cleaning machine at 4000 rpm for high-pressure deionized water cleaning and nitrogen (purity 99.999%) drying;

(5) Take the chip out and bake it on a heating table at 51°C for 18 minutes to completely remove the water vapor;

(6) The contamination of the chip surface was effectively improved under the microscope.

Example 3

A treatment method for improving surface contamination of LED chips, comprising the following steps:

(1) Clean the chip in 99.7% pure ethanol solution for 26s, then take out and use a wool brush dipped in anhydrous ethanol to gently brush the chip surface, brush the entire chip surface 6 times, and then place the chip on Rinse in deionized water for 20s with conductivity of 0.17μs/cm;

(2) Place the chip in an aqueous solution of acetic acid (purity 99.8%) with a volume ratio of 8% for 2 minutes, then take it out and use a wool brush to dip the acetic acid aqueous solution to gently brush the chip surface. The entire chip surface is brushed twice, and then the The chip was rinsed in deionized water for 21s;

(3) Place the chip in a mixed solution composed of hypochlorous acid (purity 96%), hydrofluoric acid (purity 97%), ammonium fluoride (purity 95%), sodium hydrogen fluoride (purity 98%), and deionized water (weight ratios are 3% hypochlorous acid, 0.5% hydrofluoric acid, 2% ammonium fluoride, 2% sodium hydrogen fluoride, and 92.5% deionized water) for 5s, then quickly take out and rinse with deionized water for 59s;

(4) The chip is placed in a cleaning machine at 4200 rpm for high-pressure deionized water cleaning and nitrogen (purity 99.99%) drying;

(5) Take the chip out and bake it on a heating table at 72°C for 28 minutes to completely remove the water vapor;

(6) The contamination of the chip surface was effectively improved under the microscope.

Example 4

A treatment method for improving surface contamination of LED chips, the steps of which are as described in Embodiment 1, the difference is that in step (1), the chips are placed in a 99.7% pure ethanol solution for cleaning for 10s, and then taken out Use a wool brush dipped in anhydrous ethanol to gently brush the chip surface, brush the entire chip surface 6 times, and then rinse the chip in deionized water with a conductivity of 0.2 μs/cm for 30 s.

Example 5

A treatment method for improving the surface pollution of LED chips, the steps of which are as described in Example 4, the difference is that in step (1), the chips are placed in a 99.7% pure ethanol solution for cleaning for 30s, and then taken out Use a wool brush dipped in anhydrous ethanol to gently brush the chip surface, brush the entire chip surface once, and then rinse the chip in deionized water with a conductivity of 0.2 μs/cm for 10 s.

Example 6

A treatment method for improving surface contamination of LED chips, the steps of which are as described in Example 1, the difference is that in step (2), the chips are placed in an aqueous solution of acetic acid (purity 99.6%) with a volume ratio of 2% for cleaning After 5 minutes, take out and use a wool brush dipped in acetic acid aqueous solution to gently brush the chip surface, brush the entire chip surface once, and then rinse the chip in deionized water for 10s.

Example 7

A treatment method for improving surface pollution of LED chips, the steps of which are as described in Example 6, the difference is that in step (2), the chips are placed in an aqueous solution of acetic acid (purity 99.6%) with a volume ratio of 10% for cleaning After 1 minute, take out and use a wool brush dipped in acetic acid aqueous solution to gently brush the chip surface, brush the entire chip surface 6 times, and then rinse the chip in deionized water for 30s.

Example 8

A treatment method for improving the surface pollution of LED chips, the steps of which are as described in Example 1, the difference is that in step (3), the chips are placed in formic acid (purity 95%), meta-aluminate (purity 95%) , aluminum fluoride (purity 95%), and deionized water (weight ratios are 2% formic acid, 1% metaaluminate, 2% aluminum fluoride, and 95% deionized water) for 30s, and then quickly Take out and rinse with deionized water for 60s.

Example 9

A treatment method for improving the surface contamination of LED chips, the steps are as described in Example 8, the difference is that in step (3), the chip is placed in a mixed solution for cleaning for 1 s, and then quickly taken out and placed in deionized water Rinse for 30s.

Example 10

A treatment method for improving the surface pollution of LED chips, the steps of which are as described in Embodiment 1, the difference is that in step (4), the chips are placed in a cleaning machine at 1000 rpm for high-pressure deionized water cleaning, Blow dry with nitrogen (99.99% purity).

Example 11

A treatment method for improving the surface pollution of LED chips, the steps of which are as described in Embodiment 1, the difference is that in step (4), the chips are placed in a cleaning machine at 5000 rpm for high-pressure deionized water cleaning, Blow dry with nitrogen (99.99% purity).

Example 12

A treatment method for improving surface contamination of LED chips, the steps of which are as described in Example 1, the difference is that in step (5), the chip is taken out and placed on a heating table at 80°C for 5 minutes to completely remove water vapor .

Example 13

A treatment method for improving surface contamination of LED chips, the steps of which are as described in Example 1, the difference is that in step (5), the chip is taken out and placed on a heating table at 40°C for 30 minutes to completely remove water vapor .

Claims (5)

1. a processing method for improving LED chip surface pollution, is characterized in that, comprises the steps: (1) Clean the chip in anhydrous ethanol solution for 10-30s, then take out and use a brush to dip in anhydrous ethanol to brush the surface of the chip for 1-6 times, and then place the chip in deionized water to rinse for 10-30s; (2) Clean the chip in acetic acid aqueous solution for 1-5min, the volume ratio of acetic acid aqueous solution is 2%-10%, then take out and use a brush to dip the acetic acid aqueous solution to brush the surface of the chip for 1-6 times, and then place the chip on Rinse with deionized water for 10-30s; (3) Place the chip in a mixed solution composed of acid, deionized water, and fluoride for 1-30s. The weight ratio of acid, fluoride, and deionized water is 1%-20% acid, 1% 20%, deionized water 60%-98%, then take out and rinse with deionized water for 30-60s; the acids are acetic acid, formic acid, hydrogen sulfuric acid, oxalic acid, metaaluminate, hypochlorous acid, hydrofluoric acid In one or more, described fluoride is one or more in ammonium fluoride, sodium fluoride, sodium bifluoride, aluminum fluoride; (4) Place the chip in a cleaning machine at 1000-5000 rpm for high-pressure deionized water cleaning and nitrogen drying; (5) Take the chip out and bake it on a heating table at 40-80°C for 5-30 minutes; (6) Check the improvement effect of the chip surface contamination under the microscope. If the treatment is completely finished, if the improvement still needs to be improved, go back to step (1). 2. The treatment method for improving LED chip surface pollution according to claim 1, wherein in step (1), the absolute ethanol is analytically pure, and the purity is ≥99.7%; the conductivity of the deionized water is ≤ 0.2μs/cm. 3 . The treatment method for improving LED chip surface pollution according to claim 1 , wherein, in step (2), the acetic acid in the acetic acid aqueous solution is analytically pure, and the purity is more than 99%. 4 . 4. The treatment method for improving LED chip surface pollution according to claim 1, wherein in step (3), the acetic acid, formic acid, hydrosulfuric acid, oxalic acid, metaaluminate, hypochlorous acid, ammonium fluoride , Sodium fluoride, sodium hydrogen fluoride, aluminum fluoride, and hydrofluoric acid are of analytical grade, with a purity of ≥95%. 5 . The treatment method for improving LED chip surface contamination according to claim 1 , wherein in step (4), the nitrogen purity is greater than 99.9%. 6 .

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