Pick-and-Remove System and Method for Emissive Display Repair

• US 20170140961A1
• Filed: 01/26/2017
• Published: 05/18/2017
• Est. Priority Date: 10/31/2014
• Status: Active Grant

• Current Assignee: Elux Inc.
• Original Assignee: Elux Inc.
• Inventors: Sasaki, Kenji, Schuele, Paul J., Ulmer, Kurt, Lee, Jong-Jan
• Granted Patent: US 10,446,728 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 22/22 Connection or disconnection of sub-entities or redundant parts of a device in response to a measurement testing and repair of stores after manufacture including at wafer scale G11C29/00; fuses per se H01L23/525
• CPC Class Codes: H01L 2224/95101 in a liquid medium
• CPC Class Codes: H01L 24/799 Apparatus for disconnecting
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/50 Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2933/0033 relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A system and method are provided for repairing an emissive display. Following assembly, the emissive substrate is inspected to determine defective array sites, and defect items are removed using a pick-and-remove process. In one aspect, the emissive substrate includes an array of wells, with emissive elements located in the wells, but not electrically connected to the emissive substrate. If the emissive elements are light emitting diodes (LEDs), then the emissive substrate is exposed to ultraviolet illumination to photoexcite the array of LED, so that LED illumination can be measured to determine defective array sites. The defect items may be determined to be misaligned, mis-located, or non-functional emissive elements, or debris. Subsequent to determining these defect items, the robotic pick-and-remove process is used to remove them. The pick-and-remove process can also be repurposed to populate empty wells with replacement emissive elements.

Claims

1. A pick-and-remove method for repairing an emissive display, the method comprising:

providing an emissive substrate including an array of positioned emissive elements;

inspecting the emissive substrate to determine defective array sites; and

,

in response to the inspection, using a pick-and-remove system to remove defect items from the defective array sites.

2. The method of claim 1 wherein providing the emissive substrate includes providing an emissive substrate with an array of wells, with emissive elements located in the wells, but not electrically connected to the emissive substrate.

3. The method of claim 1 wherein inspecting the emissive substrate to determine defective array sites includes determining defect items selected from a group consisting of missing emissive elements, misaligned emissive elements, mis-located emissive elements, non-functional emissive elements, and debris.

4. The method of claim 3 wherein using the pick-and-remove system includes using the pick-and-remove system to remove misaligned emissive elements, mis-located emissive elements, non-functional emissive elements, and debris from a top surface of the emissive substrate.

5. The method of claim 1 wherein using the pick-and-remove system includes using a phase-change holding mechanism.

6. The method of claim 5 wherein using the phase-change holding mechanism includes:

coating a pick-and-remove transfer head with a liquid phase polymer;

subsequent to contacting a defect item with the transfer head, permitting the transfer head to cool;

converting the polymer to a solid phase attached to the defect item.

7. The method of claim 6 wherein coating the pick-and-remove transfer head includes coating one pick-and-remove transfer head from a plurality pick-and-remove transfer heads;

and,

the method further comprising;

subsequent to attaching the defect item, disposing of the transfer head.

8. The method of claim 6 further comprising:

subsequent to attaching the defect item, cleaning the transfer head to remove the defective emissive element; and

,

recoating the transfer head with a liquid phase polymer.

9. The method of claim 1 further comprising:

subsequent to removing the defect item, using a process selected from the group consisting of fluidic assembly or a repurposed pick-and-remove system to populate empty wells with replacement emissive elements.

10. The method of claim 9 further comprising:

subsequent to populating the empty wells with replacement emissive elements, reinspecting the emissive substrate to determine defective array sites;

subsequent to passing reinspection, annealing the emissive substrate; and

,

in response to the annealing, electrically connecting the emissive elements to the emissive substrate.

11. The method of claim 2 wherein providing the emissive substrate includes providing light emitting diode (LED) emissive elements;

and,

wherein inspecting the emissive substrate includes;

irradiating the emissive substrate with ultraviolet (UV) illumination;

photoexciting the array of LED; and

,

measuring LED illumination at predetermined wavelengths to determine defective array sites.

12. The method of claim 1 wherein using the pick-and-remove system to remove defect items using the electrostatic holding mechanism as follows:

creating an electrostatic charge between a pick-and-remove transfer head and a defect item;

attracting the defect item to the transfer head in response to the electrostatic charge; and

removing the electrostatic charge to release the defect item emissive element from the transfer head.

13. The method of claim 1 wherein using a pick-and-remove system to remove defect items includes using an adhesive holding mechanism as follows:

providing a pick-and-remove deformable contact surface area transfer head that is adhesive with respect to a defect item;

expanding the transfer head deformable contact surface area to contact the defect item; and

,

in response to the contact, attaching the defect item to the transfer head.

14. The method of claim 9 wherein providing the emissive substrate includes providing an emissive substrate with an array of wells populated with emissive elements;

wherein populating empty wells with replacement emissive elements using the repurposed pick-and-remove system includes;

attaching a replacement emissive element to a pick-and-remove transfer head;

positioning the replacement emissive element on the emissive substrate top surface at a location proximate to a well to be populated;

translating the replacement emissive element across top surface; and

,

in response to translating the replacement emissive element over an opening in the well, using elastic deformation force to direct the replacement emissive element into the well.

15. An emissive display repair system, the system comprising:

an inspection subsystem for inspecting an emissive substrate with an array of wells, with emissive elements located in the wells, but not electrically connected to the emissive substrate, and determining defective array sites; and

,

a pick-and-remove subsystem for removing defect items from the emissive substrate.

16. The system of claim 15 wherein the emissive elements are light emitting diodes (LEDs);

wherein inspection subsystem comprises;

an illuminator for irradiating the emissive substrate with ultraviolet (UV) spectrum light and photoexciting the LEDs; and

,

a dual-mode image sensor for measuring visual contrast and edge detection in a first mode, and wavelength-specific filtration in a second mode to identify functional LEDs.

17. The system of claim 15 wherein the inspection subsystem determines defect items selected from a group consisting of missing emissive elements, misaligned emissive elements, mis-located emissive elements, non-functional emissive elements, and debris.

18. The system of claim 17 wherein the inspection subsystem determines a defect item selected from the group consisting of misaligned emissive elements, mis-located emissive elements, non-functional emissive elements, or debris;

and,

wherein the pick-and-remove subsystem uses a robotic pick-and-remove device to remove the defect item.

19. The system of claim 18 wherein the robotic pick-and-remove devices uses a holding mechanism selected from the group consisting of electrostatic, mechanical, and adhesive.

20. The system of claim 19 wherein the electrostatic pick-and-remove device includes a transfer head capable of creating an electrostatic charge to attract the defect item to the transfer head, and dissipating the electrostatic charge on the transfer head to release the defect item.

21. The system of claim 19 wherein the mechanical pick-and-remove device includes:

a thermal transfer head;

a liquid phase polymer coating overlying the thermal transfer head; and

,

wherein the thermal transfer head, subsequent to contacting a defect item, is cooled to convert the liquid phase polymer to a solid phase attached to the defect item.

22. The system of claim 21 wherein the thermal transfer head is cleaned of the polymer to remove the defect item, and recoated with a liquid phase polymer for subsequent use.

23. The system of claim 21 wherein the thermal transfer head is disposed of with the attached defect item.

24. The system of claim 19 wherein the adhesive pick-and-remove device includes:

a transfer head with a deformable contact surface area that is adhesive with respect to a defect item; and

,

wherein the transfer head becomes adhesively attached a defect item in response to expanding the contact surface area size.

25. The system of claim 24 further comprising:

a replacement subsystem for populating empty wells with replacement emissive elements, the replacement subsystem using a process selected from the group consisting of fluidic assembly or a repurposed pick-and-remove device.