Micro device arrangement in donor substrate

Patent metadata

Field	Value
Publication number	US-11892497-B2
Application number	US-202318179894-A
Country	US
Kind code	B2
Filing date	Mar 7, 2023
Priority date	Oct 4, 2016
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

This disclosure is related to arranging micro devices in the donor substrate by either patterning or population so that there is no interfering with non-receiving pads and the non-interfering area in the donor substrate is maximized. This enables the transfer of micro devices to a receiver substrate with fewer steps.

First claim

We claim:

1. A method of populating a receiver substrate, the method comprising the steps of:
preparing a plurality of microdevices on one or more donor substrates;
transferring the plurality of microdevices from the one or more donor substrates to a first cartridge substrate, wherein the first cartridge includes three different types of micro devices and a spare micro device or a void area, the plurality of microdevices are arranged in arrays;
selecting at least one set of microdevices in the first cartridge substrate associated with a set of contact pads in the receiver substrate;
identifying a number of defective microdevices in the at least one set of microdevices;
correcting the defective microdevices if the number of defective microdevices in the set is more than a set threshold value; and
aligning and transferring the selected set of microdevices on the first cartridge substrate to corresponding contact pads on the receiver substrate.

2. The method of claim 1 , wherein after transferring the selected set of microdevices to the receiver substrate, if the receiver substrate is not fully populated, the method further comprising the steps of:
determining whether the first cartridge substrate 1) has enough microdevices to continue transferring microdevices to the receiver substrate or 2) has not enough microdevices to continue transferring microdevices to the receiver substrate,
in response to determining that the first cartridge substrate has enough microdevices, selecting another set of microdevices in the first cartridge substrate for transferring to the receiver substrate; else in response to determining that the first cartridge substrate has not enough microdevices, selecting a second cartridge substrate wherein the second cartridge substrate includes three different types of micro devices and a spare micro device or a void area.

3. The method of claim 1 , wherein the defective microdevices are removed if the number of the defective microdevices is more than the set threshold value.

4. The method of claim 1 , wherein the defective microdevices are repaired if the number of the defective microdevices is less than the set threshold value.

5. The method of claim 1 , wherein the defective microdevices are replaced with spare microdevices on each cartridge substrate if the number of the defective microdevices is less than the set threshold value.

6. The method of claim 1 , wherein the step of selecting one or more sets of microdevices on the first cartridge substrate and the second cartridge substrate comprising:
selecting one or more sets of microdevices, wherein number of defected microdevices in one or more sets of microdevices is less than a threshold value; and
transferring the selected set of microdevices to populate the system substrate.

7. The method of claim 1 , wherein the first cartridge substrate and the second cartridge substrate includes different types of the plurality of microdevices.

8. The method of claim 7 , wherein the different types of microdevices comprises red color microdevices, blue color microdevices or green color microdevices.

9. The method of claim 1 , wherein the different types of microdevices are arranged in arrays on each cartridge according to a type of microdevice.

10. The method of claim 1 , further comprising:
biasing the microdevices through the receiver substrate to test a connection between the transferred microdevices and the receiver substrate.

11. The method of claim 1 , further comprising:
adjusting one or more of the bonding parameters of the microdevices to correct the cause of the defective microdevices.

12. The method of claim 1 , wherein a distance between the plurality of microdevices on each cartridge substrate depends on a pitch of corresponding contact pads on the receiver substrate.

13. The method according to claim 1 , wherein rows of the micro devices from each cartridge substrate are placed in a skewed arrangement on the receiver substrate to reduce the effect of abrupt transitions caused by non-uniformity of microdevices across each cartridge substrate.

14. The method according to claim 1 , wherein laterally adjacent rows of the micro devices from different cartridge substrates are placed in a flipped arrangement on the receiver substrate with the high or low side of a row from one of the donor substrates adjacent to a high side or low side, respectively, of an adjacent row of another donor substrate to reduce abrupt transitions caused by non-uniformity of micro devices across each cartridge substrate.

15. The method according to claim 1 , wherein vertically adjacent rows of micro devices from different cartridge substrates are placed in an alternating arrangement with high sides vertically adjacent to low sides to reduce abrupt transitions caused by non-uniformity of micro devices across each cartridge substrate.

16. The method of claim 1 wherein for the first set of micro devices related to a pixel pitch in the receiver substrate, there are different lateral and vertical pitches, a void area, or an interfering area, between laterally and vertically adjacent sets of pixels.

17. The method of claim 16 wherein the pitch the receiver substrate compensates for any mismatch between a pixel pitch and a micro device pitch (landing area pitch) enabling micro devices on the donor or cartridge substrate to not interfere with pads, e.g. the horizontally and vertically adjacent cluster, or existing micro devices on the receiver substrate.

18. The method of claim 17 , wherein the void area is defined by at least a distance from one side of an outer pad of the pixel to a far side of the outer pad at an opposite side of the pixel or at least the distance of N times the pitch of the pads, where N is the number of adjacent (horizontally or vertically) pads in the pixel wherein further a length is an entire length of the cartridge.

19. The method of claim 1 , wherein the plurality of groups of micro devices form a pixel, from each array or set of micro devices, and are mounted on the receiver substrate simultaneously, and the cartridge or the receiver substrate both are moved relative to each other into alignment with a subsequent plurality of clusters of pads, and the mounting process is repeated, until the cartridge is empty or the receiver substrate is filled.

20. The method of claim 1 , wherein the micro devices, prepared on the donor substrate before transferring to the e cartridge, use supporting layers, for individual micro devices or for a group of micro devices wherein, the micro device pitch matches the pitch in the cartridge or it is a multiple of the cartridge pitch.

21. The method of claim 1 , wherein flipping the micro devices, alternating the high and low performing micro devices at inner sides, and skewing the edges to improve an average uniformity furthermore wherein further the micro device performance alternates between high and low in both directions of adjacent horizontal blocks and in adjacent vertical blocks.

22. The method of claim 21 , wherein the performance of micro devices at edges of the blocks are matched for adjacent transferred blocks prior to the transfer to the receiver substrate.

23. The method of claim 21 , wherein two or more blocks are used to populate a block in the cartridge or receiver substrate and wherein further the method of skewing or flipping is used to improve the average uniformity.

24. The method of claim 23 , wherein a random or predefin

Assignees

• Vuereal Inc

Inventors

• Chaji Gholamreza
• Fathi Ehsanollah

Classifications

• H10P72/7434

  used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate · CPC title

• H10P72/74 Primary

  using temporarily an auxiliary support · CPC title

• H10W72/0198

  batch processes · CPC title

• H10W46/301

  for alignment · CPC title

• H10W72/073 Primary

  of die-attach connectors · CPC title