Electrode alignment method of reverse polarity AlGaInP quaternary LED chip

Abstract

The invention relates to an electrode alignment method of a reverse polarity AlGaInP quaternary LED chip. The method comprises the following steps: growing a layer of Au or AuBe film on a P surface ofan epitaxial wafer of the reverse polarity AlGaInP quaternary LED, obtaining a P-surface ohm contact pattern through a conventional photoetching method, and reserving two symmetric marks at upper andlower or left and right edge locations of the epitaxial wafer, and removing N-surface corresponding to the marks of reverse polarity AlGaInP quaternary LED chip after accomplishing bonding and substrate corroding to transparent and visible through a way of taking the photoresist or metal film as a mask according to the marks reserved at the P surface, namely, exposing the N-type AlGaInP layer; aligning the N-surface ohm contact pattern with the P-surface ohm contact pattern according to the markers. The alignment method is simpler and more practical, the alignment degree is high, the chip loss is reduced, the chip quality is improved, the operation is simple and more stable light-exiting effect can be obtained, and the method is suitable for the scale production.

Description

technical field [0001] The invention relates to an electrode alignment method of a reverse polarity AlGaInP quaternary LED chip, belonging to the field of optoelectronic technology. Background technique [0002] LED is a new light source for lighting in the 21st century. Under the same brightness, the power consumption of semiconductor lamps is only 1 / 10 of that of ordinary incandescent lamps, but the life span can be extended by 100 times. The LED device is a cold light source with high luminous efficiency, low working voltage, low power consumption, small size, flat packaging, easy to develop thin and light products, strong structure and long life. The light source itself does not contain harmful substances such as mercury and lead. No infrared and ultraviolet pollution, no pollution to the outside world during production and use. Therefore, semiconductor lamps have the characteristics of energy saving, environmental protection, and long life. Just like transistors replac...

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Problems solved by technology

[0004] At this stage, reverse polarity AlGaInP quaternary LED chips are widely used in the field of high-power red LED display screens. Reverse polarity means replacing the substrate, and replacing the GaAs substrate with large light absorption with a single crystal conductive Si substrate or sapphire substrate. Bottom, etc. After the replacement is completed, the GaAs substrate is etched away, and the corrosion barrier layer is etched to expose the heavily doped layer. Afterwards, an Au film needs to be evaporated on the heavily doped layer to form an ohmic contact, and the N-side ohmic contact layer pattern is prepared by subsequent photolithography. , in order to ensure better current spreading and higher brightness of the reverse polarity AlGaInP, the ohmic contact pattern on the N side is generally aligned with the ohmic contact pattern on the P side, because the middle part of the epitaxial layer of the reverse polarity AlGaInP quaternary LED chip is not Light transmission, current electrode alignment generally selectively corrodes the epitaxial layer in some areas when preparing N-side ohmic contact patterns. This method has uncertainty and great loss to the chip, so how to effectively align and reduce The loss of chips has become the main problem at this stage

[0005] Chinese patent document CN104518056A discloses a method for preparing a reverse-polarity AlGaInP red LED chip, which mainly involves removing the residual metal film layer on the edge of the wafer between the two steps of stripping the GaAs substrate and etching the barrier layer. It avoids the contamination of the wafer before evaporating the N-type electrode, ensures the clean surface of the chip, and avoids the problem of electrode missing in the subsequent process, which leads to downgrade and lower yield. It involves the registration mark pattern, but the area of ​​this pattern is relatively small Causes a large loss of chips and does not specify the relevant preparation process. Poor practicability

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