A tray assembly includes a base tray, and an anti-slip pad disposed on the base tray, wherein the anti-slip pad has a friction coefficient in a range of about 0.5 to about 20 based on ASTM D1894, and a surface resistance in a range of about 10{circumflex over ()}6 ?/cm.sup.2 to about 10{circumflex over ()}9 ?/cm.sup.2 based on ASTM D257, and the anti-slip pad includes at least one of a thermoplastic olefinic elastomer (TPO), natural rubber, styrene-butadiene rubber (SBR), and polypropylene (PP).

A microLED mass transfer stamping system includes a stamp substrate with an array of trap sites, each configured with a columnar-shaped recess to temporarily secure a keel extended from a bottom surface of a microLED. In the case of surface mount microLEDs, the keel is electrically nonconductive. In the case of vertical microLEDs, the keel is an electrically conductive second electrode. The stamping system also includes a fluidic assembly carrier substrate with an array of wells having a pitch separating adjacent wells that matches the pitch separating the stamp substrate trap sites. A display substrate includes an array of microLED pads with the same pitch as the trap sites. The stamp substrate top surface is pressed against the display substrate, with each trap site interfacing a corresponding microLED site, and the microLEDs are transferred. Fluidic assembly stamp substrates are also presented for use with microLEDs having keels or axial leads.

A tray assembly includes a base tray, and an anti-slip pad disposed on the base tray, wherein the anti-slip pad has a friction coefficient in a range of about 0.5 to about 20 based on ASTM D1894, and a surface resistance in a range of about 10{circumflex over ()}6 /cm.sup.2 to about 10{circumflex over ()}9 /cm.sup.2 based on ASTM D257, and the anti-slip pad includes at least one of a thermoplastic olefinic elastomer (TPO), natural rubber, styrene-butadiene rubber (SBR), and polypropylene (PP).