Processing method for improving identifiability of LED bonding wire electrode
Technical Field
The invention relates to the technical field of LED manufacturing, in particular to a processing method for improving the identifiability of an LED bonding wire electrode.
Background
The appearance of the LED completely replaces the traditional incandescent lamp and fluorescent lamp, the LED is developed into the current full-color LED from the initial blue LED, the LED is applied to various fields such as civil use, commercial use, military use and the like, the luminous efficiency is improved by about one order of magnitude every 10 years, and the white light luminous efficiency reaches more than 110lm/W and exceeds the incandescent lamp. The LED lighting technology is developed rapidly, and meanwhile, the LED lighting technology is continuously upgraded and updated, so that higher use requirements of people are met. The manufacturing process of the LED mainly comprises the steps of substrate manufacturing, epitaxial growth, chip manufacturing, chip packaging and the like, wherein the production quality of the LED chip is an important factor influencing the product cost, index and sales. The chip has high quality and good stability, and can meet the downstream use requirements, and the application of the LED is an important link with higher added value in the whole industrial chain. The manufacturing quality of the chip is completely the advantages and disadvantages of electrode firmness and surface flatness, roughness and weldability, and the electrode firmness and electrode weldability are relatively good for most chip manufacturers, the problems of electrode falling and difficult wire welding are small in probability, but the electrode surface flatness and the roughness of the chip are difficult to control due to the influence of chip process and equipment precision difference. At present, the surface of a chip electrode has more or less unevenness or stripe-shaped fluctuation, and besides being related to an electrode evaporation process and evaporation equipment, the flatness of an epitaxial surface is also an important influence factor influencing the final electrode surface flatness, and the problem is difficult to effectively solve only by adjusting the evaporation process and equipment parameters.
The flatness and roughness of the surface of the chip electrode directly affect the production efficiency of downstream packaging manufacturers, mainly because the electrode surface is dull and lackluster due to rough and uneven surface of the chip electrode, and good color difference can not be formed between the electrode surface and the chip surface, so that the identifiability of the packaging bonding wire electrode is affected, equipment alarms and stops routing when bonding wires are caused, even the bonding wires are deflected, the efficiency and the quality are affected, and the problem that equipment needs to be readjusted or standard samples need to be corrected is solved. Due to the difference of production levels of different chip manufacturers, the surface of the electrode of the current chip is difficult to achieve high consistency, so that downstream packaging manufacturers need to adjust welding wire standards according to different goods sources, or the phenomenon of frequent routing alarm for different products under the same standard is caused.
Disclosure of Invention
In order to overcome the defects of the technology, the invention provides a processing method for improving the surface roughness of an electrode by a rapid processing technology of laser on the surface of the electrode in a vacuum environment so as to improve the identifiability of the packaging bonding wire electrode.
The technical scheme adopted by the invention for overcoming the technical problems is as follows:
a processing method for improving the identifiability of an LED bonding wire electrode comprises the following steps:
a) cleaning the LED chip in pure water after the electrode evaporation and before the pattern is manufactured, removing floating dust and particles on the surface of the LED chip, and drying after cleaning;
b) blowing the surface of the LED chip by using nitrogen to remove particles and floating dust on the surface of the LED chip;
c) placing the LED chip in the closed cavity, and vacuumizing the closed cavity;
d) opening a laser in the closed cavity, adjusting the laser energy density and pulse frequency of the laser to enable the generated light beam to uniformly act on the surface of the LED chip, and melting the surface of the LED chip at high temperature by the energy generated by the laser beam;
e) breaking vacuum, taking out the LED chip irradiated by the laser, putting the LED chip into an atmosphere environment of nitrogen or argon for annealing treatment, and continuously introducing the nitrogen or argon after the annealing treatment until the temperature of the LED chip is naturally reduced to be less than or equal to 30 ℃ and then taking out the LED chip;
f) and carrying out a pattern manufacturing process on the LED chip to finish the treatment of the surface of the electrode.
Further, the purity of the nitrogen in the step b) is more than or equal to 99.99 percent.
Further, an XY-axis moving platform is arranged in the closed containing cavity in the step c), and the LED chip is arranged on the XY-axis moving platform.
Further, the vacuum degree in the step c) is more than 3.0 multiplied by 10-6Torr。
Further, the wavelength of the laser in the step d) is 248-2) The pulse frequency of the laser is 50-200Hz, and the time for irradiating the surface of the LED chip by the laser is 30-300 seconds.
Further, the purity of the nitrogen or the argon in the step e) is more than or equal to 99.99 percent.
Further, the temperature of annealing in the step e) is 60-150 ℃, and the treatment time is 3-10 minutes. The invention has the beneficial effects that: because the surface of the cleaned and dried LED chip is melted after being irradiated by a laser beam emitted by a laser under a vacuum environment, the LED chip flows into the groove at the low point position after being heated and melted at the micro angle, and is filled up, thereby improving the roughness of the surface of the LED chip, being convenient to operate, having no damage to the surface of the chip, not influencing the appearance quality of the chip, effectively improving the roughness and the brightness of the surface of an electrode of the chip, improving the identifiability of an electrode welding wire, and ensuring the packaging production efficiency and the product yield of the LED chip.
Detailed Description
The present invention is further explained below.
A processing method for improving the identifiability of an LED bonding wire electrode comprises the following steps:
a) cleaning the LED chip in pure water after the electrode evaporation and before the pattern is manufactured, removing floating dust and particles on the surface of the LED chip, and drying after cleaning;
b) blowing the surface of the LED chip by using nitrogen to remove particles and floating dust on the surface of the LED chip;
c) placing the LED chip in the closed cavity, and vacuumizing the closed cavity;
d) opening a laser in the closed cavity, adjusting the laser energy density and pulse frequency of the laser to enable the generated light beam to uniformly act on the surface of the LED chip, and melting the surface of the LED chip at high temperature by the energy generated by the laser beam;
e) breaking vacuum, taking out the LED chip irradiated by the laser, putting the LED chip into an atmosphere environment of nitrogen or argon for annealing treatment, and continuously introducing the nitrogen or argon after the annealing treatment until the temperature of the LED chip is naturally reduced to be less than or equal to 30 ℃ and then taking out the LED chip;
f) and carrying out a pattern manufacturing process on the LED chip to finish the treatment of the surface of the electrode.
Because the surface of the cleaned and dried LED chip is melted after being irradiated by a laser beam emitted by a laser under a vacuum environment, the LED chip flows into the groove at the low point position after being heated and melted at the micro angle, and is filled up, thereby improving the roughness of the surface of the LED chip, being convenient to operate, having no damage to the surface of the chip, not influencing the appearance quality of the chip, effectively improving the roughness and the brightness of the surface of an electrode of the chip, improving the identifiability of an electrode welding wire, and ensuring the packaging production efficiency and the product yield of the LED chip.
Example 1:
the purity of the nitrogen in the step b) is more than or equal to 99.99 percent.
Example 2:
and c) an XY-axis moving platform is arranged in the closed accommodating cavity, and the LED chip is arranged on the XY-axis moving platform. The LED chip can be driven to move back and forth and left and right along the horizontal direction through the XY circumference moving platform, and the uniform action of the laser beam on the surface of the LED chip is ensured.
Example 3:
the vacuum degree in the step c) is more than 3.0 multiplied by 10-6Torr。
Example 4:
the wavelength of the laser in the step d) is 248-1064nm, and the energy density of the laser is 0.05-1.0J/(pulse-cm)2) The pulse frequency of the laser is 50-200Hz, and the time for irradiating the surface of the LED chip by the laser is 30-300 seconds.
Example 5:
the purity of the nitrogen or argon in the step e) is more than or equal to 99.99 percent.
Example 6:
the temperature of annealing in the step e) is 60-150 ℃, and the treatment time is 3-10 minutes.