Systems and methods for controlling release of transferable semiconductor structures

摘要

The disclosed technology relates generally to methods and systems for controlling the release of micro devices. Prior to transferring micro devices to a destination substrate, a native substrate is formed with micro devices thereon. The micro devices can be distributed over the native substrate and spatially separated from each other by an anchor structure. The anchors are physically connected/secured to the native substrate. Tethers physically secure each micro device to one or more anchors, thereby suspending the micro device above the native substrate. In certain embodiments, single tether designs are used to control the relaxation of built-in stress in releasable structures on a substrate, such as Si (1 1 1). Single tether designs offer, among other things, the added benefit of easier break upon retrieval from native substrate in micro assembly processes. In certain embodiments, narrow tether designs are used to avoid pinning of the undercut etch front.

主权项

1. An array of micro devices, the array comprising:
a source substrate having a process side; a sacrificial layer comprising sacrificial material on the process side of the source substrate; a plurality of releasable micro objects formed at least in part on the sacrificial layer; a plurality of anchor structures located on the process side of the source substrate, wherein the anchor structures remain rigidly attached to the source substrate in the absence of the sacrificial material; and a plurality of tethers, wherein each tether of the plurality of tethers connects a releasable micro object of the plurality of releasable micro objects to a portion of one of the anchor structures, wherein:
the portion of the anchor to which the tether connects laterally separates adjacent releasable micro objects,each releasable micro object is connected to an anchor by a single tether,the source substrate is a growth substrate made of a substrate material on or over which the micro objects are formed and the tethers are made of a tether material,either the tether material is the same material as the substrate material or the tether material is not disposed between the releasable micro objects and the source substrate, andthe tethers are shaped to fracture in response to pressure.