Adhesive wafer bonding with controlled thickness variation

#1. Field

#The present invention relates to micro devices. More particularly embodiments of the present invention relate to the stabilization of micro devices on a carrier substrate.

#2. Background Information

#FIG. 1A is a cross-sectional side view illustration of a bulk LED substrate in accordance with an embodiment of the invention.

#FIG. 1B is a cross-sectional side view illustration of a device wafer including circuitry in accordance with an embodiment of the invention.

#FIG. 2A is a cross-sectional side view illustration of a patterned conductive contact layer on a bulk LED substrate in accordance with an embodiment of the invention.

#Embodiments of the present invention describe a method and structure for stabilizing an array of micro devices such as micro light emitting diode (LED) devices and micro chips on a carrier substrate having raised spacers so that they are poised for pick up and transfer to a receiving substrate. For example, the receiving substrate may be, but is not limited to, a display substrate, a lighting substrate, a substrate with functional devices such as transistors or integrated circuits (ICs), or a substrate with metal redistribution lines. While embodiments of some of the present invention are described with specific regard to micro LED devices comprising p-n diodes, it is to be appreciated that embodiments of the invention are not so limited and that certain embodiments may also be applicable to other micro semiconductor devices which are designed in such a way so as to perform a predetermined electronic function (e.g. diode, transistor, integrated circuit) or photonic function (LED, laser). Other embodiments of the present invention are described with specific regard to micro devices including circuitry. For example, the micro devices may be based on silicon or SOI wafers for logic or memory applications, or based on GaAs wafers for RF communications applications.

#In various embodiments, description is made with reference to figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions and processes, etc., in order to provide a thorough understanding of the present invention. In other instances, well-known semiconductor processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the present invention. Reference throughout this specification to “one embodiment,” “an embodiment” or the like means that a particular feature, structure, configuration, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase “in one embodiment,” “an embodiment” or the like in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments.

#The terms “upon”, “over”, “spanning”, “to”, “between”, and “on” as used herein may refer to a relative position of one layer with respect to other layers. One layer “upon”, “over”, “spanning”, or “on” another layer or bonded “to” another layer may be directly in contact with the other layer or may have one or more intervening layers. One layer “between” layers may be directly in contact with the layers or may have one or more intervening layers.