The invention relates to development of microdevices on a substrate that can be released and transferred to a system substrate.
The invention relates to a method to selectively transfer microdevices from a cartridge substrate to a system substrate, the method comprising, bringing a cartridge substrate closer to the system substrate, bringing a selected microdevice in contact with pads in the system substrate, bonding the selected microdevice to the pads in the system substrate, and where the release layer for the first selected microdevice from the cartridge substrate is modified or removed prior to the transfer such that the selected microdevice is held to the cartridge substrate with a lower force than the bonding force of the selected microdevice to the pad.
The foregoing and other advantages of the disclosure will become apparent upon reading the following detailed description and upon reference to the drawings.
While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of an invention as defined by the appended claims.
In this description, the term “device” and “microdevice” are used interchangeably. However, it is clear to one skilled in the art that the embodiments described here are independent of the device size.
Microdevices can be microLED, OLED, microsensors, MEMs, and any other type of devices.
In one case, the microdevice has a functional body and contacts. The contacts can be electrical, optical or mechanical contacts.
In the case of optoelectronic microdevices, the device can have functional layers and charge carrying layers. Where charge carrying layers (doped layers, ohmics and contacts) transfer the charges (electron of hole) between the functional layers and contacts outside the device. The functional layers can generate electromagnetic signals (e.g., lights) or absorb electromagnetic signals.
System substrates can have pixels and pixel circuits that each pixel control at least one microdevice. Pixel circuits can be made of electrodes, transistors or other components. The transistors can be fabricated with a thin film process, CMOS, or organic materials.
The invention described and its related embodiments show a method to selectively transfer microdevices from a donor/cartridge substrate to a system substrate.
There can be other microdevices 104-3 in the donor/cartridge substrate 102 that do not interfere with another pad on the system substrate. The release layer 106-3 for these devices 104-3 can be changed or not.
The selective removal or change of the release layer for microdevices that are being transferred to the system substrate and do not interfere with the unwanted area can be done through selective chemical process, etching, thermal, or laser process.
For selective chemical processes, a photoresist can be patterned on the donor substrate and enable access to the selective microdevices 104-1. As a result, the chemical can only change or remove the release layer 106-1 associated with the selected microdevices. After the selected microdevices are transferred (it can be in one transfer cycle or multiple transfer cycles), another photoresist can be patterned and enable access to the newly selected microdevices.
In another related embodiment, different release layers can be used so that each release layer is modified or removed by a selected chemical. As a result, the first chemical removes the release layer 106-1 related to the selected microdevice 104-1. After transferring the first selected microdevices to the system substrate, a second chemical is used that removes or modifies the release layer associated with the second set of microdevices.
In another related embodiment, the different release layer in a donor substrate can have different modification or removal mechanisms such as one set can have a chemical release layer, one set laser and so on.
In another related embodiment, the bonding part of the pads can be formed only for the first selected microdevices. After the transfer of the first selected microdevices, the bonding part of the pads for the second selected microdevices are formed on the system substrate. This process enables further selectivity.
In another related embodiment, the bonding part of the microdevices related to the repair process are formed after the testing and identifying the defective microdevices (or pixels) in the system substrate.
In related embodiments microdevices can be coupled to the backplane or another housing layer through a membrane or anchor layer.
As demonstrated in
A second bonding pad set is formed onto the system substrate 120. The second set bonding pad exists on the system substrate and gets activated. The activation can be by removing a top layer, thermal, plasma, or other factors.
As demonstrated in
As shown in
As demonstrated in
While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/CA2022/051211 | 8/9/2022 | WO |
Number | Date | Country | |
---|---|---|---|
63230875 | Aug 2021 | US |