Other

Lucent Technologies Inc.

At&t Bell Laboratories

Cecilia Y Mak

Kam S Law

Charles H Henry

Yuan P Li

Barry Irwin Miller

Henry H Yaffe

Edward J Laskowski

Leonard C Feldman

Gregg S Higashi

A processing method for depositing porous silica and doped silica films is provided. The method uses a cyclic scheme wherein each cycle comprises first codepositing silica with silicon, then selectively removing the silicon from the codeposit to form a porous structure. In a preferred embodiment, the codeposition is carried out by plasma enhanced chemical vapor deposition. After codeposition, the codeposit is exposed to a selective silicon removal reagent that can preferentially remove the silicon in the codeposit, leaving behind a porous structure. Repeated execution of the codeposition and the selective silicon removal steps build up thickness of the porous film. A porous film with highly uniform small pores and a desired porosity profile can be obtained with this method. This method is advantageous for forming a broad range of low-k dielectrics for semiconductor integrated circuit fabrication. The general method is also advantageous for forming other porous films for other applications.

Method for depositing porous films

A processing method for depositing porous silica and doped silica films is provided. The method uses a cyclic scheme wherein each cycle comprises first codepositing silica with silicon, then selectively removing the silicon to form a porous structure. In a preferred embodiment, the codeposition is carried out by plasma enhanced chemical vapor deposition. The reagent feed stream comprises a mixture of codeposition reagents and a selective silicon removal reagent. RF power modulation is used to control the codeposition and the selective silicon removal steps with the later proceeds whenever the RF power is turned off or reduced to a low level. A porous film with highly uniform small pores and a desired porosity profile can be obtained with this method. This method is advantageous for forming a broad range of low-k dielectrics for semiconductor integrated circuit fabrication. The method is also advantageous for forming other porous films for other applications.

In accordance with the invention, a new type of monolithic optical waveguide filter comprises a chain of optical couplers of different effective lengths linked by differential delays of different lengths. The transfer of the chain of couplers and delays is the sum of contributions from all possible optical paths, each contribution forming a term in a Fourier series whose sum forms the optical output. A desired frequency response is obtained by optimizing the lengths of the couplers and the delay paths so that the Fourier series best approximates the desired response. The filter is advantageously optimized so that it is insensitive to uncontrolled fabrication errors and is short in length. The wavelength dependence of practical waveguide properties is advantageously incorporated in the optimization. Consequently, the filter is highly manufacturable by mass production. Such filters have been shown to meet the requirements for separating the 1.3 and 1.551 .mu.m telecommunications channels and for flattening the gain of Er amplifiers.

Monolithic optical waveguide filters based on Fourier expansion

It has been found that selective metallization in integrated circuits is expeditiously achieved through a copper plating procedure. In this process, palladium silicide is used as a catalytic surface and an electroless plating bath is employed to introduce copper plating only in regions where the silicide is present. Use of this procedure yields superior filling of vias and windows with excellent conductivity.

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Bedminster, NJ, United States of America

Cecilia Y Mak