Circuit board, LED module, display device, and method for manufacturing LED module and method for manufacturing display device

Abstract

The purpose of the present invention is to form a stable connection structure with a back plate as a flip-chip LED. An LED module includes a first electrode and a second electrode disposed on the substrate, an LED chip disposed on the first electrode and the second electrode, and a first bump between the LED chip and the first electrode, and a second bump between the LED chip and the second electrode. The LED chip includes a cathode electrode facing the first electrode, an anode electrode facing the second electrode, and a step portion between the cathode electrode and the anode electrode, a distance between the first electrode and the cathode electrode is larger than a distance between the second electrode and the anode electrode, and the first bump is disposed to embed the step portion.

Description

technical field [0001] The present invention relates to an LED module in which light emitting diodes (LED: Light Emitting Diode) are arranged, a display device in which LEDs are mounted in pixels, and a circuit board before LEDs are mounted. Background technique [0002] There is known a micro LED display in which tiny light-emitting diodes called micro LEDs are mounted in pixels arranged in a matrix. The micro LED display has a structure in which micro LEDs solidified from a wafer or the like are mounted on a substrate on which a circuit called a backplane is formed. Micro LEDs are tiny chips, so the ratio of the cross-sectional area to the area of ​​the planar view becomes large. As a result, the micro LED has a problem that the influence of non-radiative recombination occurring at the side wall of the active layer can no longer be ignored, and the luminous efficiency decreases. [0003] In order to improve light extraction efficiency, there is known a flip-chip micro LE...

AI Technical Summary

Problems solved by technology

As a result, Micro LED has such a problem that the influence of non-radiative recombination occurring at the side wall of the active layer can no longer be ignored, and the luminous efficiency decreases

However, making bumps separately for cathodes and anodes is a major cause of complicated manufacturing processes and increased manufacturing costs.

On the other hand, in the planar electrode structure or the structure in which the cathode electrode is drawn out on the p-type semiconductor layer, the short circuit between electrodes becomes a problem.

That is, since the chip size of the LED is small, the distance between the cathode electrode and the anode electrode becomes narrow, and if the solder forming the bumps flows during the mounting process, the short circuit between the cathode electrode and the anode electrode becomes a problem.

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