A process for filling one or more etched holes defined in a frontside surface of a wafer substrate. The process includes the steps of: (i) depositing a layer of a thermoplastic first polymer onto the frontside surface and into each hole; (ii) reflowing the first polymer; (iii) exposing the wafer substrate to a controlled oxidative plasma; (iv) optionally repeating steps (i) to (iii); (v) depositing a layer of a photoimageable second polymer; (vi) selectively removing the second polymer from regions outside a periphery of the holes using exposure and development; and (vii) planarizing the frontside surface to provide holes filled with a plug comprising the first and second polymers, which are different than each other. Each plug has a respective upper surface coplanar with the frontside surface.

A production method for a composite substrate according to the present invention comprises (a) a step of mirror-polishing a piezoelectric-substrate side of a laminated substrate formed by bonding a piezoelectric substrate and a support substrate; (b) a step of performing machining using an ion beam or a neutral atom beam so that a thickness of an outer peripheral portion of the piezoelectric substrate is larger than a thickness of an inner peripheral portion and a difference between a largest thickness and a smallest thickness of the inner peripheral portion of the piezoelectric substrate is 100 nm or less over an entire surface; and (c) a step of flattening the entire surface of the piezoelectric substrate to remove at least a part of an altered layer formed by the machining using the ion beam or the neutral atom beam in the step (b).

Methods of reversing the tone of a pattern having non-uniformly sized features. The methods include depositing a highly conformal hard mask layer over the patterned layer with a non-planar protective coating and etch schemes for minimizing critical dimension variations.

A method creates MEMS structures by selectively etching a silicon wafer that is patterned by using a masking layer. The method comprises depositing and patterning a first mask on a silicon wafer to define desired first areas on the wafer to be etched. First trenches are etched on parts of the wafer not covered by the first mask. The first trenches are filled with a deposit layer. A part of the deposit layer is removed on desired second areas to be etched and a remainder is left on areas to function as a second mask to define final structures. Parts of the wafer on the desired second areas is etched, and the second mask is removed. A gyroscope or accelerator can be manufactured by dimensioning the structures.