Dissolution and swelling of thin films of ionizable polymers in contact with aqueous alkaline solutions are examined using a quartz crystal microbalance, while simultaneously recording the visible reflectivity and infrared absorption of the evolving films. From these data changes in the thickness, depth structure, composition, mass, and mechanical properties of the polymer film during its interaction with the aqueous solution can be detected. Analysis of these provides evidence for the formation of interfacial gel layers resulting from acid−base reaction of the polymer with the hydroxide solution and yields information on the kinetics of transport and chemical reaction that control the overall process. Kinetics simulations indicate that the most important factors influencing observed behaviors are the intrinsic reactivity of ionizable groups on the polymer and the response of the film's mechanical properties, which determine the ability of small molecules to move through it, to incorporation of water.

Characterization of Reactive Dissolution and Swelling of Polymer Films Using a Quartz Crystal Microbalance and Visible and Infrared Reflectance Spectroscopy

A new model is proposed to describe the development of positive photoresist over the full range of exposure. The model includes the depth dependence of development rate and is capable of fitting measured data of all resists examined to date. A measurement system for determining the exposure and development model parameters is described. Several types of photoresist and developer have been characterized under a number of processing conditions. The effect of the development model parameters on developed resist profiles is illustrated using simulation.

Development of positive photoresist

Step and flash imprint lithography : a low-pressure, room-temperature nanoimprint lithograph

A thin film thickness monitor uses the successive reflection of polychromatic light from a reference or standard thin film having a varying optical thickness (n1 t1) and then from a thin film of unknown thickness (tf) or optical thickness (nf tf). The reflected intensity of light from the thin film is detected to provide a signal indicating when the optical thickness of the unknown film is equal to the optical thickness of the reference.

Thin film thickness monitor

The injection laser

A system has been developed which permits the measurement of dielectric film thicknesses in-situ during development or etching processes. This can be extended to growth or deposition processes. Two examples of its uses are presented: the determination of the thickness of phosphosilicate glass layers on silicon dioxide coated silicon wafers by making use of the etch rate differences, and the monitoring of photoresist thickness during development to characterize the photoresist development process.

K.L. Konnerth

Papers

In-situ measurement of dielectric thickness during etching or developing processes

Turn-on delay in gallium arsenide lasers operated at room temperature