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The importance of miniaturisation of hybrid microwave integrated circuits (HMICs) and the increasingly stringent demands on the line‐width control of conductor lines in satellite communications and digital radio systems are well established. The importance of photolithographic processes for achieving accuracy and control of the line width necessary to guarantee performance and repeatability of HMICs is acknowledged. The purpose of this paper is to discuss problems concerning the photoresist deposition process and how spin coating is necessary for obtaining the quality, precision and repeatability required for fine line HMICs for high frequency applications.

Morton International Inc. have purchased Hoechst AG's printed circuit materials business including their Ozatec dry film and liquid primary imaging photoresists, Ozatec liquid photoimageable solder masks and related process equipment. Concurrently, Hoechst and its US subsidiary Hoechst Celanese Corporation purchased Morton's semiconductor photoresist business. Completion of these transactions was effective from 4 August 1993.

President Bush recently announced that Northern Telecom had received a presidential award recognising innovation and leadership in protecting the environment. Fulfilling a pledge made in 1988, Northern Telecom became the world's first large electronics company to meet a public commitment to eliminate ozone‐depleting CFC‐113 solvents from its 42 worldwide manufacturing operations. The goal was achieved nine years ahead of the mandate set by the Montreal Protocol, an international agreement signed by 68 nations that calls for the elimination of CFCs and other ozone‐depleting substances by the year 2000.

Alan Hobby has recently been appointed Applications Engineer at DEK Printing Machines Ltd, Weymouth. In 1968 he joined Ferranti at Bracknell and became one of the small team setting up the thick film production unit. Four years later he joined EMI at Hayes as the Production Engineer, where he gained experience in the manufacture of high volume but relatively simple hybrids. In 1975 Alan moved to Marconi Electronic Devices Ltd at Portsmouth, where he was one of the engineers responsible for the company's programme of qualification as a hybrid manufacturer for the European Space Agency and for their BS 9450 approval programme. Since then he has been concerned with the development of printing and firing techniques both at Portsmouth and at Marconi's high volume production unit at Swindon.

Electro‐Science Laboratories Inc., whose thick film pastes and materials for the microelectronics industry are manufactured and distributed in Europe by Agmet Ltd of Reading, have announced that Michael Alan Stein was elected President with effect from 16 September 1988. At the same time Dr Sidney J. Stein was elected Chairman of the Board of Directors.

A quantitative investigation of a dipping technique for depositing a thin layer of resist on circularly symmetrical objects is presented. The results obtained are valuable for preparing three‐dimensional (3‐D) surfaces suited for spatial microlithographic processes in the 1 to 10 µm linewidth range.

This paper describes a method for patterning fine line interconnections over non‐planar surfaces and introduces the idea of using holographic masks for more challenging geometries.

A photolithographic method for achieving grossly non‐planar interconnects is described. The patterning of electrical interconnections onto the piezo‐electric actuators of an ink‐jet print head is used as an example. Uniform coverage of the substrate is achieved using an electro‐depositable photoresist. The required pattern is transferred via a custom‐designed chrome‐on‐glass mask using a standard mask aligner.

Large arrays of 100 μm‐pitch electrical interconnections were successfully deposited onto 500 μm‐high high piezo‐electric actuators. It was necessary to modify the shapes of the line segments on the mask in order to compensate for diffractive line broadening. For more extreme 3D geometries it becomes necessary to consider the use of holographic masks.

Printed circuit boards and semiconductor wafers are nominally flat and traditional lithographic processes have been developed accordingly. However, future microelectronic packaging schemes and microsystems may require patterning to be achieved on grossly non‐planar surfaces. We have demonstrated that this can be achieved on ink‐jet print heads using photolithography and point to the research necessary to enable it to be realised on more extreme non‐planar substrates.