Jds Uniphase Corporation

Applied Materials, Inc.

Cypress Semiconductor Corporation

Sanjay M Thekdi

Robert Brainard

Anantharaman Vaidyanathan

Ajay Kumar

Anisul Haque Khan

Thomas Nguyen

David K Nakamoto

Jyoti Kiron Bhardwaj

Barthelemy Fondeur

Jianmin Qiao

David J Dougherty

Zi-Wen Dong

Sharma V Pamarthy

Hiroaki Yamada

Anca L Sala

Erik W Egan

Niranjan Gopinathan

Yingchao Yan

Suresh Ramalingam

Douglas E Crafts

Dragan Valentin Podlesnik

Alain Paul Blosse

James E Nulty

Manuj Rathor

James F Farrell

Kenzo Ishida

Steven M Swain

David J Chapman

Mark Brian Farrelly

Duncan Harwood

Tom Truong

Ian Hutagalung

The present application relates to a method of fabricating planar circuits using a photo lithographic mask set, to the photo lithographic mask set, and to a planar circuit fabricated with the photo lithographic mask set. The instant invention involves separating a photo lithographic mask into two parts, namely, a master mask and one or more slave masks. The master mask and the one or more slave masks form a photo lithographic mask set that is used iteratively to fabricate the planar circuits. In particular, the master mask is used as a template to provide the general layout for the planar circuit, while each slave mask is varied to tune and/or tailor the planar circuit. Since only a small portion of the planar circuit is redesigned and/or rewritten as a new mask (i.e., the slave mask), the instant invention provides a simple and cost effective method for optimizing planar circuits. Furthermore, since most mask errors will originate from the master mask, the instant invention provides an efficient method of correcting errors on planar circuits using the one or more slave masks.

Planar circuit optimization

The invention relates to a variable optical attenuator constructed as a Mach Zehnder planar lightwave circuit, particularly including a channel waveguide support structure for heat isolation and stress relief to reduce polarization dependent loss (PDL) and power consumption in the device. Power reduction trenches comprise longitudinal segments having small stress relief pillars of cladding material left in between them in the etching process. The waveguides of the MZI are supported by a main pillar structure and integral stress relief pillars which remain after removal of the trenches. The waveguide is surrounded by air on three sides for improved heat isolation. The performance of the present invention shows substantial improvement in PDL and extinction ratio over the prior art continuous trench design, and also, to a smaller degree, over the case where power reduction trenches are not used at all. Segmented trenches appear to allow for the lowest stress on the two waveguide arms of all the cases including no trench and trenched devices.

Planar lightwave circuit variable optical attenuator

A method of making a semiconductor structure comprises forming a hole through a first dielectric layer; followed by forming a hole through an etch-stop layer, to expose a first conducting layer. The thickness of the etch-stop layer is at least one-half the smallest line width of the first conducting layer.

Contact structure and method of making the same

Openings of variable shape are made sequentially by alternately etching an opening in silicon and depositing a conformal fluorocarbon polymer on the sidewalls. This polymer protects the sidewalls of the opening from further etching. An isotropic etch can be carried out to change the profile of the etched feature, and for lift-off of the etched feature from the silicon substrate.

Etching multi-shaped openings in silicon

A planar lightwave circuit includes at least one optical waveguide core, and at least one feature proximate the core having a stress-engineered property to balance stress and therefore minimize birefringence affecting the core. A protective passivation layer is formed over the core and the feature to be substantially non-interfering with the balanced stress provided by the feature. The stress balancing feature may be an overcladding layer formed over the core, doped to have a coefficient of thermal expansion approximately matched to that of an underlying substrate, to symmetrically distribute stress in an undercladding between the overcladding and the substrate, away from the core. The protective passivation layer is formed to have a coefficient of thermal expansion approximately matched to that of the overcladding. In one exemplary embodiment, the passivation layer is formed from silicon nitride. Related concepts of stress release grooves, and core overetching, are also disclosed.

Waveguide stress engineering and compatible passivation in planar lightwave circuits

Micro devices are formed in situ in a high density in a substrate comprising a masked silicon layer over a stop layer of a silicon compound, by anisotropically etching the desired feature in the silicon layer, overetching to form a notch at the silicon-stop layer interface, depositing a protective fluorocarbon polymer layer on the sidewalls and bottom of the etched silicon layer, and isotropically etching to separate the etched feature from the stop layer. This method avoids the problems of stiction common in other methods of forming micro devices.

Method of releasing devices from a substrate

A planar lightwave circuit includes an arrayed waveguide grating (AWG), with input and output waveguides, partially curved array waveguides with respective length differences, and planar waveguide regions for focusing optical energy between the input/output and array waveguides. Optimal waveguide widths and spacing along the planar waveguide region facets are disclosed, which are largely determinative of AWG size and optical performance. Also disclosed are optimal cross-sectional waveguide dimensions (e.g., width and height); modified index of refraction difference between the waveguide core and cladding regions; and optimal array waveguide lengths, path length differences, and free spectral range. These features, especially when combined with advanced fiber attachment, passivation and packaging techniques, result in high-yield, high-performance AWGs (both gaussian and flattop versions).

Compact, low insertion loss, high yield arrayed waveguide grating

A method of etching high aspect ratio, anisotropic deep trench openings in a silicon substrate coated with a multilayer mask comprising in sequence a pad oxide layer, a silicon nitride layer, a doped or undoped silicon oxide hard mask layer, a polysilicon hard mask layer, an antireflection coating and a patterned photoresist layer in a single chamber comprising patterning the antireflection coating and hard mask layer, removing the photoresist and antireflection layers with oxygen, using the patterned polysilicon as a hard mask layer etching an opening in the silicon oxide hard mask layer, the silicon nitride layer and the pad oxide layer, removing the polysilicon hard mask layer with CF4/CHF3, and etching an anisotropic deep trench in the silicon substrate using the patterned silicon oxide hard mask layer as a mask and an etchant mixture including nitrogen trifluoride that self-cleans the chamber.

Process for in-situ etching a hardmask stack

A plasma etch chemistry and etch methodology is provided to improve critical dimension control for openings formed into and/or through a semiconductor thin film. According to an embodiment, the plasma etch chemistry includes an etchant mixture comprising a first etchant of the formula C H F (where x&gE;2, y&gE;1 and z&gE;2) and a second etchant other than the first etchant to form the openings. The relationship of x, y and z may be such that y&plus;z equals an even number &lE;2x&plus;2. According to an alternative embodiment, the plasma etch chemistry further includes strained cyclic (hydro)fluorocarbon. The plasma etch chemistry may be used to form openings in the layer in a single-etch step. In a further embodiment, the plasma etch chemistry described herein may etch less than the entire thickness of the layer, and a second plasma etch chemistry substantially free of the first etchant and strained cyclic (hydro)fluorocarbons etches the remainder of the layer to form the openings. Such an etch methodology advantageously reduces the risk of etching the materials underlying the layer.

Plasma etch chemistry and method of improving etch control

A method for conditioning a plasma etch chamber is presented. A plasma etch chamber is provided, which preferably includes a chuck for supporting a topography. A conditioning process may be performed in the etch chamber. The conditioning process preferably includes positioning a cover topography on or above the chuck. A conditioning feed gas containing (hydro)halocarbons may be introduced into the chamber. A conditioning plasma may be generated from the conditioning feed gas for a conditioning time. Immediately after generating the conditioning plasma is complete, the overall thickness of the cover topography is preferably at least as great as immediately before generating the conditioning plasma. By performing a conditioning process in such a manner, the total cost and complexity of the conditioning process may be reduced.

Method for conditioning a plasma etch chamber

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Santa Clara, CA, United States of America

Sanjay M Thekdi