[share] sapphire substrate grinding trilogy

First, grinding the first song - waxing

The primary action of the LED chip grinding process is “above waxing”, which has the same meaning as the CMP chemical grinding of silicon chips. The chip is mounted on an iron (Lapping process) or ceramic (Grounding process) disk. Firstly apply the solid wax evenly on the disc heated to about 90~110 °C, then place the front side of the chip on the disc. After pressing and cooling, the chip is fixed on the disc surface to complete the waxing action. .

The process of waxing must control the thickness of the wax to 2~3um, which has a direct influence on the choice of the wax, the pressing method and the conditions, and directly relates to the uniformity of the finished thickness after grinding. The parts of the pressurizing and cooling mechanism of the waxing machine can be roughly divided into two types, one is to directly pressurize the two discs, and the other is to add a vacuum chamber in addition to the pressurized disc. When the pressure is applied, the cabin is evacuated to increase the effect of evenly flattening the wax.

In both ways, strictly speaking, the difference is not large. However, some chips are not suitable for waxing in a vacuum-pressing manner. For example, if the chip is marked on the flat side of the front side of the chip before the epitaxial process, when the vacuum is applied, the grade of the flat side is used. The bulge will cause the wax under the chip to be sucked out by vacuum, resulting in insufficient wax thickness. When grinding, the flat edge area is easily worn away. In addition to causing the grinding of the corners, it is also easy to crack the chip due to the occurrence of cracks.

However, the design of pressurization and cooling is also different. Generally, the lower disc will have a cooling water pipe coiled in the disc. However, some of them start to add cooling water for cooling after tens of seconds or two minutes of pressurization, while others are pressurized while cooling.

When working on waxing, there is a problem, that is, bubbles on the chip when waxing. Air bubbles can make the chip not completely attached to the iron plate or ceramic plate, which will cause small cracks after grinding. (If the chip produces a small cross or herringbone crack after grinding, it is caused by the dust not being removed when the wax is applied.) However, there have been automatic waxing machines such as WEC and TECDIA. When the robot takes the film, the bubble size can be controlled to be less than 0.5 mm, and after the pressure cooling, the wax on the chip is in a good condition. However, if you use the SpeedFAM manual waxing machine to remove wax, remove the 1mm bubble in the wax, you must rely on the operator's experience and methods to get the best waxing effect.

Second, LED chip grinding two songs - grinding

After the completion of the waxing process, the next process is the "debris process" with the highest destructive power.

The most mature grinding process in the past was Lapping, which was to use the alumina grinding powder for the first grinding. The method of operation is to measure and set the diamond dots on the periphery of the iron plate using a dial gauge, and then place it on the grinding disc and use the grinding powder for grinding. The purpose of using diamond dots is to make the chip to a set thickness. Since the hardness of the diamond is the highest, the chip will not be worn again.

Samsung Ceramic Chip Capacitors

Samsung Capacitor,Samsung Chip Capacitors,Original Samsung Capacitor,Samsung Ceramic Chip Capacitors