CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of Taiwan Patent Application No. 108133180, filed on Sep. 16, 2019, the entirety of which is incorporated by reference herein.

BACKGROUND

Field of the Disclosure

The disclosure relates to a micro semiconductor chip, a micro semiconductor structure, and a transfer device which is used to transfer the micro semiconductor chip.

Description of the Related Art

With the advancements being made in the field of optoelectronics technology, the size of optoelectronic components has gradually evolved toward miniaturization. In recent years, due to breakthroughs in the size of light-emitting diodes (LEDs), micro light-emitting diode (micro LED) displays, in which arrays of light-emitting diodes are arranged in an array, have increasingly interested people in the field. A micro LED display is an active micro semiconductor device display, and it is more energy-efficient than organic light-emitting diode (OLED) displays. Furthermore, a micro LED display has better contrast performance than an OLED display, and it is visible in sunlight.

The performance of the micro light-emitting diode display depends on the light extraction efficiency of the micro light-emitting diode chip used in the micro light-emitting diode display. Therefore, a novel micro light-emitting diode chip with improved light extraction efficiency is desired.

BRIEF SUMMARY

According to embodiments of the disclosure, the disclosure provides a micro semiconductor chip. The micro semiconductor chip includes an epitaxial structure, a first-type electrode, a second-type electrode, and a top light guide element. The epitaxial structure has a top surface, a bottom surface, and a side surface, wherein the top surface is opposite the bottom surface, and the side surface connects the top surface to the bottom surface. The first-type electrode and the second-type electrode disposed on the bottom surface of the epitaxial structure. The top light guide element is disposed on the top surface of the epitaxial structure, wherein the top light guide element has a light extraction surface and a bottom surface, wherein the edge of the light extraction surface may completely overlap the edge of the bottom surface of the top light guide element, and the light extraction surface of the micro semiconductor chip is a curved surface, a combination of at least two curved surfaces, or a combination of at least one curved surface and at least one planar surface. The bottom surface of the top light guide element is in contact with the epitaxial structure.

According to embodiments of the disclosure, the top light guide element consists of a thermal curable material, wherein the thermal curable material has a thermal curing temperature from about 50° C. to 250° C.

According to embodiments of the disclosure, the refractive index of the thermal curable material is greater than 1, and the refractive index of the thermal curable material can be less than or equal to the refractive index of the epitaxial structure.

According to embodiments of the disclosure, the light transmittance of the thermal curable material is greater than or equal to 80%.

According to embodiments of the disclosure, the thermal curable material is a photoresist material, such as negative photoresist.

According to embodiments of the disclosure, the thermal curable material thermoplastic polysiloxane resin, thermoplastic epoxy resin, thermolplastic polyimide resin, or a combination thereof.

According to embodiments of the disclosure, an orthogonal projection of the light extraction surface onto the top surface of the epitaxial structure has an area S2, and the top surface of the epitaxial structure has an area S1, wherein S2/S1is between 0.7 and 1.

According to embodiments of the disclosure, the ratio (H1/H) of the maximum height H1of the top light guide element in the light extraction direction to the maximum height H of the epitaxial structure in the light extraction direction is between 0.1 and 0.5.

According to embodiments of the disclosure, a chamfer is formed at the connection of the top surface of the epitaxial structure and the side surface of the epitaxial structure.

According to embodiments of the disclosure, the micro semiconductor chip further includes an insulating layer disposed on the side surface of the epitaxial structure.

According to embodiments of the disclosure, the micro semiconductor chip further includes a side light guide element disposed on the side surface.

According to embodiments of the disclosure, the refractive index of the side light guide element is greater than 1, and the refractive index of the side light guide element is less than or equal to the refractive index of the epitaxial structure.

According to embodiments of the disclosure, the top light guide element and the side light guide element are made of the same material.

According to embodiments of the disclosure, the disclosure provides a micro semiconductor structure. The micro semiconductor structure includes a substrate, at least one of the micro semiconductor chips disposed on the substrate, and at least one supporting element. One end of the supporting element is disposed on the substrate, and the other of the supporting element is connected to the side surface of the micro semiconductor chip so that the micro semiconductor chip is fixed to the substrate via the supporting element.

According to embodiments of the disclosure, the top light guide element and the supporting element are made of the same material.

According to embodiments of the disclosure, the top light guide element, the side light guide element is integrated with the supporting element.

According to embodiments of the disclosure, the disclosure provides a transfer device. The transfer device is used to transfer the aforementioned micro semiconductor chip, or to dispose the aforementioned micro semiconductor chip of the micro semiconductor structure. The transfer device includes at least one pickup element which is used to pick up the micro semiconductor chip, wherein the pickup element has a transferring surface, and the contour of the transferring surface matches the contour of at least a part of the light extraction surface of the micro semiconductor chip.

According to embodiments of the disclosure, the transferring surface of the pickup element is a curved surface, a combination of at least two curved surfaces, or a combination of at least one curved surface and at least one planar surface.

According to embodiments of the disclosure, the light extraction surface of the micro semiconductor chip has an area A1. The contour of the light extraction surface, which matches the contour of the transferring surface, of the top light guide element of the micro semiconductor chip has an area A2. In particular, A2/A1is between 0.5 and 1.

