Staggered and tile stacked microdevice integration and driving

Abstract

What is disclosed is structures and methods to integrate microdevices into system or receiver substrates. The integration of microdevices is facilitated by adding staging pads to microdevices before or after transferring. Creating stages after the transfer of a first microdevice to a substrate for the subsequent microdevice transfer to the first (or the second) microdevice transfer. The stage improves the surface profile of the substrate so that next microdevice can be transferred without the first microdevice on the substrate get damaged by or interfere with the surface of the donor or transfer head. Some embodiments further relate to tiled display device and more particularly, to stacking tiles to a backplane to form the tiled display device.

We claim: 
     
         1 . A method of stacking tile structure layers to a substrate, each tile structure layer comprising plurality of microdevices, the method comprising:
 releasing a first tile structure layer on the substrate;   providing and aligning a second tile structure layer with the first tile structure layer on the substrate; and   bonding the first tile structure layer and the second tile structure layer on the substrate, wherein the first tile structure and the second tile structure are physically separated from each other.   
     
     
         2 . The method of  claim 1 , wherein the second tile structure layer aligned with the first tile structure layer through alignment marks. 
     
     
         3 . The method of  claim 1 , wherein the second tile structure layer bonded to the first tile structure layer through means of an adhesive layer or bonding pads. 
     
     
         4 . The method of  claim 1 , wherein the first tile structure layer and second tile structure layer is covered with planarization layers and metalization layers. 
     
     
         5 . The method of  claim 4 , further comprising
 providing vias through the planarization layers to connect first tile structure layer and second tile structure layer together or provide connection to connect different tile structure layers to the substrate.   
     
     
         6 . The method of  claim 1 , further comprising
 providing vias through first tile structure layer and second tile structure layer to couple the tile layers to controlling and biasing signals.   
     
     
         7 . The method of  claim 1 , wherein the substrate is one of: a temporary substrate, a system substrate or a backplane. 
     
     
         8 . The method of  claim 1 , wherein the substrate is affixed to either a bottom surface, a top surface or in between the tile layer structures. 
     
     
         9 . The method of  claim 1 , wherein the microdevices are of the same or different colors. 
     
     
         10 . The method of  claim 1 , further comprising
 providing driving circuitry on the substrate prior to stacking the tile layer structures.   
     
     
         11 . The method of  claim 1 , further comprising
 testing each tile structure layer prior to stacking.   
     
     
         12 . The method of  claim 1 , further comprising
 providing bonding layers between the tile structures layers for enabling integration of microdevices.   
     
     
         13 . The method of  claim 1 , further comprising
 providing common electrode between each tile structure layer for connecting at least one terminal of the microdevices together.   
     
     
         14 . The method of  claim 1 , further comprising
 forming an optical structure on each microdevice at different tile structure layers.   
     
     
         15 . The method of  claim 1 , wherein the bonding layers is one of adhesive or bonding pads. 
     
     
         16 . The method of  claim 15 , wherein the adhesive is one of: SU8, Polyamide, UV or thermal curable epoxy. 
     
     
         17 . The method of  claim 15 , wherein the bonding pads is one of: Au/In, Au/Au or other materials compatible with compression, thermal compression, and eutectic bonding methods. 
     
     
         18 . The method of  claim 17 , wherein the bonding pads formed on either side of the microdevice between the tile structures layers. 
     
     
         19 . The method of  claim 1  wherein the second tile structure layer has dents in the planarization layer to receive microdevices from the first tile layer structure. 
     
     
         20 . The method of  claim 1 , wherein an excess of planarization layer around the microdevices in the first layer structure is removed to ease the bonding. 
     
     
         21 . A display device comprising:
 a plurality of tile structures stacked with each other, each of the tile structure including:
 a substrate; 
 an array of microdevices disposed on the substrate; 
 top electrodes disposed on a first surface of each microdevice; and 
 bottom electrodes disposed on a surface opposite to the first surface of the microdevices; and 
   a backplane bonded to the plurality of the tile structures.   
     
     
         22 . The display device of  claim 21 , wherein the plurality of tile structures transferred to a temporary substrate before bonding with the backplane. 
     
     
         23 . The display device of  claim 21 , wherein the plurality of tile structures are bonded with each other through a bonding layer in between. 
     
     
         24 . The display device of  claim 21 , wherein a planarization layer is formed between the array of microdevices for each tile structure. 
     
     
         25 . The display device of  claim 21 , wherein the planarization layer provides openings for the top electrodes and the bottom electrodes to make connections with microdevices. 
     
     
         26 . The display device of  claim 21 , wherein a common electrode is provided between each tile structures for connecting the microdevices together. 
     
     
         27 . The display device of  claim 21 , wherein the bottom electrodes comprise bonding pads for the microdevices to bond with the backplane. 
     
     
         28 . The display device of  claim 21 , wherein the backplane comprises driving circuitry and contact pads corresponding to the bonding pads of the microdevices. 
     
     
         29 . The display device of  claim 21 , wherein an optical layer is provided on the temporary substrate prior to stacking tile structures to the temporary substrate. 
     
     
         30 . The display device of  claim 21 , wherein the stacked tiles structures are patterned to create islands at the temporary substrate or after bonding to the backplane. 
     
     
         31 . The display device of  claim 21 , wherein a reflective layer is provided around the islands to reduce viewing angle effect by directing the light from different tile structures to one surface. 
     
     
         32 . The display device of  claim 21 , wherein the temporary substrate is removed after bonding with the backplane. 
     
     
         33 . The display device of  claim 21 , wherein a space between the microdevices is filled by a filling material before or after bonding with the backplane.