The present disclosure relates to a flip-chip package with a hollow-cavity and reinforced interconnects, and a process for making the same. The disclosed flip-chip package includes a substrate, a reinforcement layer over an upper surface of the substrate, a flip-chip die attached to the upper surface of the substrate by interconnects through the reinforcement layer, an air cavity formed between the substrate and the flip-chip die, and a protective layer encapsulating the flip-chip die and defining a perimeter of the air cavity. Herein, a first portion of each interconnect is encapsulated by the reinforcement layer and a second portion of each interconnect is exposed to the air cavity. The reinforcement layer provides reinforcement to each interconnect.

Fan-out wafer-level packaging (WLP) using metal foil lamination is provided. An example wafer-level package incorporates a metal foil, such as copper (Cu), to relocate bonding pads in lieu of a conventional deposited or plated RDL. A polymer such as an epoxy layer adheres the metal foil to the package creating conductive contacts between the metal foil and metal pillars of a die. The metal foil may be patterned at different stages of a fabrication process. An example wafer-level package with metal foil provides relatively inexpensive electroplating-free traces that replace expensive RDL processes. Example techniques can reduce interfacial stress at fan-out areas to enhance package reliability, and enable smaller chips to be used. The metal foil provides improved fidelity of high frequency signals. The metal foil can be bonded to metallic pillar bumps before molding, resulting in less impact on the mold material.

A method for manufacturing a micro LED display is provided. The method includes providing a plurality of LED elements on a first substrate, transferring, using a magnetic holder or a vacuum holder, at least two of the plurality of LED elements of the same primary color from the first substrate to a second substrate, performing the steps of the providing and the transferring with respect to three primary colors, forming an array of RGB LED units on the second substrate, each of the array of RGB LED units including a red LED element, a green LED element, and a blue LED element, interposing the array of RGB LED units between the second substrate and an LED driver wafer, detaching the second substrate from the array of RGB LED units, and interposing the array of RGB LED units between the LED driver wafer and a cover.

This disclosure provides a package structure and its fabrication method. The package structure includes: a protective insulation layer; a wiring layer including at least one metal wire and disposed on the protective insulation layer; and a first package unit disposed on the wiring layer and including a plurality of metal pillars, a first integrated-circuit chip and a first molding compound layer; wherein the plural metal pillars are located in a pillar region and electrically connected to the at least one metal wire, the first integrated-circuit chip is located in a device region and electrically connected to the at least one metal wire, and the first molding compound layer filling up the remaining part of the first package unit.

A variable-stiffness module includes a rigid structure having a first stiffness, an intermediate substrate having a second stiffness less than the first stiffness, and a flexible substrate having a third stiffness less than the second stiffness. The rigid structure is disposed on the intermediate substrate and the intermediate substrate is disposed on the flexible substrate. A conductor is disposed partially on the intermediate substrate and partially on the flexible substrate and is connected to the rigid structure. The conductor extends from the rigid structure to the intermediate substrate to the flexible substrate. In some embodiments, a variable-stiffness module includes any combination of multiple rigid structures, multiple intermediate substrates, and multiple conductors. The conductor can be an optical conductor or an electrical conductor and can be disposed over the rigid structure or between the rigid structure and the intermediate substrate.