Techniques for joining dissimilar materials in microelectronics are provided. Example techniques direct-bond dissimilar materials at an ambient room temperature, using a thin oxide, carbide, nitride, carbonitride, or oxynitride intermediary with a thickness between 100-1000 nanometers. The intermediary may comprise silicon. The dissimilar materials may have significantly different coefficients of thermal expansion (CTEs) and/or significantly different crystal-lattice unit cell geometries or dimensions, conventionally resulting in too much strain to make direct-bonding feasible. A curing period at ambient room temperature after the direct bonding of dissimilar materials allows direct bonds to strengthen by over 200%. A relatively low temperature anneal applied slowly at a rate of 1 C. temperature increase per minute, or less, further strengthens and consolidates the direct bonds. The example techniques can direct-bond lithium tantalate LiTaO.sub.3 to various conventional substrates in a process for making various novel optical and acoustic devices.

An SOI wafer contains a compressively stressed buried insulator structure. In one example, the stressed buried insulator (BOX) may be formed on a host wafer by forming silicon oxide, silicon nitride and silicon oxide layers so that the silicon nitride layer is compressively stressed. Wafer bonding provides the surface silicon layer over the stressed insulator layer. Preferred implementations of the invention form MOS transistors by etching isolation trenches into a preferred SOI substrate having a stressed BOX structure to define transistor active areas on the surface of the SOI substrate. Most preferably the trenches are formed deep enough to penetrate through the stressed BOX structure and some distance into the underlying silicon portion of the substrate. The overlying silicon active regions will have tensile stress induced due to elastic edge relaxation.

A cost effective process flow for manufacturing semiconductor on insulator structures is parallel is provided. Each of the multiple semiconductor-on-insulator composite structures prepared in parallel comprises a charge trapping layer (CTL).

A method of forming a semiconductor device includes mounting a bottom wafer on a bottom chuck and mounting a top wafer on a top chuck, wherein one of the bottom chuck and the top chuck has a gasket. The top chuck is moved towards the bottom chuck. The gasket forms a sealed region between the bottom chuck and the top chuck around the top wafer and the bottom wafer. An ambient pressure in the sealed region is adjusted. The top wafer is bonded to the bottom wafer.

Disclosed herein are methods for direct bonding. In some embodiments, the direct bonding method includes microwave annealing a dielectric bonding layer of a first element by exposing the dielectric bonding layer to microwave radiation and then directly bonding the dielectric bonding layer of the first element to a second element without an intervening adhesive. The bonding method also includes depositing the dielectric bonding layer on a semiconductor portion of the first element at a first temperature and microwave annealing the dielectric bonding layer at a second temperature lower than the first temperature.

A method for producing a planar semiconductor surface includes forming a workpiece that has a carrier substrate, one or more insulating layers, a semiconductor layer, a first etch stop layer, and a second etch stop layer; forming a contact on the workpiece; biasing the workpiece to a second voltage through the contact; etching the second etch stop layer and part of the first etch stop layer with a photo-electrochemical etching and the second voltage that selectively removes the second etch stop layer faster than the first etch stop layer; biasing the workpiece to a first voltage through the contact; and etching the first etch stop layer and part of the semiconductor layer with the photo-electrochemical etching and the first voltage that selectively removes the first etch stop layer faster than the semiconductor layer to produce a semiconductor device with a planar surface on the semiconductor layer.

A method of forming a semiconductor device is provided. The method includes forming an etch stop layer on a substrate having a first thickness, forming an epitaxial layer on the etch stop layer, and forming a wafer device on the epitaxial layer. The wafer device is bonded to a bonding wafer using hybrid bonding. The substrate is then ground to a second thickness less than the first thickness and planarized to a third thickness less than the second thickness. A mask layer is deposited on a bottom surface of the etch stop layer, and at least one via opening is formed in the mask layer. The etch stop layer is selectively removed, and the mask layer is removed to expose the substrate at the third thickness.

The present description concerns a method of manufacturing a first wafer, intended to be assembled to a second wafer by molecular bonding, including the successive steps of: forming a stack of layers at the surface of a substrate; and successive chemical etchings of the edges of said layers from the layer of the stack most distant from the substrate, across a smaller and smaller width.

A method for bonding semiconductor dies, resulting semiconductor devices, and associated systems and methods are disclosed. In some embodiments, the method includes depositing a first material on the first semiconductor die. The first material has a first outer surface and a first chemical composition at the first outer surface. The method also includes depositing a second material on the second semiconductor die. The second material has a second outer surface and a second chemical composition at the second outer surface that is different from the first chemical composition. The method also includes stacking the dies. The second outer surface of the second semiconductor die is in contact with the first outer surface of the first semiconductor die in the stack. The method also includes reacting the first outer surface with the second outer surface. The reaction causes the first outer surface to bond to the second outer surface.

A manufacturing method of a chip-attached substrate includes preparing a stacked substrate including multiple chips, a first substrate to which the multiple chips are temporarily bonded, and a second substrate bonded to the first substrate with the multiple chips therebetween; and separating the multiple chips bonded to the first substrate and the second substrate from the first substrate to bond the multiple chips to one surface of a third substrate including a device layer.