Resist Master Preparation Line

The Nimbus Resist Master Preparation (RMP) line operates entirely within its own Class 100 cleanroom environment and consists of a Cleaner, Coater, 6-bay Curing station and a Surface Analyser. Available in both Manual and Automated configuration, the RMP line is able to produce coated glass for every format. Nimbus guarantees a yield of 90%. However, in continuous production the Automated RMP line is capable of processing 12 glasses per hour and maintaining a yield greater than 95%.

The first stage in mastering is to coat the glass substrate with a light-sensitive chemical called photo-resist. The stages involved in producing a coated glass ready for recording are listed below:

• Fine Cleaner
• Coater
• Curing Ovens
• Surface Analyser
• Automation

Formats Supported
CD CD-R CD-RW MD-MO DVD DVD-RAM DVD-R DVD-RW DVD+RW

Master Metalliser

The Nimbus Technology Metalliser employs a small volume load lock system, such that the process chamber is always under vacuum. A high efficiency pump allows longer processing at lower energy levels, making glass recycling easier whilst maintaining a cycle time of only 6 minutes. Loading is controlled by a foot switch and the cycle is started by a one push button. A plug-in handset gives extensive control of process conditions and provides the operator with comprehensive diagnostic information. The process is controlled by preset vacuum pressures to give consistent results, even on start-up. The whole chamber, pump system and handling are contained within a standard Nimbus module. Only a small cut-out is needed in the clean room wall, which allows regular maintenance and target changing to be performed from the service corridor and minimises contamination in the clean room. The control electronics are housed within a single control cabinet. The Nimbus Technology Metalliser can be integrated in either the manual or automated Developer/Metalliser Line. It is also available as a stand alone unit contained within a single bay laminar flow module.

Universal Autodeveloper

Based on the Dual Density Autodeveloper, the Universal Autodeveloper employs the same proven principles but has been designed to reflect the increasing requirement for a mastering suite to produce more formats than just CD and DVD. The Universal Autodeveloper uses a 543nm wavelength HeNe green laser and a single moveable first order sensor. The sensor position is servo controlled and can be placed to monitor the first order diffracted beam from discs of any track pitch from 2.0 µm to 0.4 µm. This makes it possible to develop any of the following formats - CD, CD-R, CD-RW, DVD (5, 9, 10, 14, 18), DVD-R, DVD-RAM, DVD-RW, +RW as well as many magneto optical formats and higher density products still under development. The correct position for the first order sensor is calculated automatically from the track pitch value entered by the user. A second sensor monitors the intensity of the incident laser beam and is used to normalise the first order reading to compensate for fluctuations of laser power. Developing can be monitored at any position across the program area from radius 20 mm to 65 mm.

The Universal Autodeveloper is controlled from a PC running Windows NT. The user interface gives extended control over the developing cycle, offering as many as ten separate steps within a cycle. Once cycle parameters are defined, they can be saved as a Preset and recalled by clicking the Preset name from a drop-down box. As well as development by time and to a simple first order value, the user can choose from several more sophisticated options for stopping developing - for example, it is possible to stop developing at a preset first order value on a negative slope, which is required for continuous groove formats where the mastered pit width is more than 50% of the track pitch.

The Nimbus Technology Dual Density and Universal Autodevelopers enable a mastering system to produce consistent and reliable results for today's standard formats and for the next generation of pre-recorded and recordable discs.

Both models are based on a patented submerged optical head design which monitors the first order diffracted beam during development and enables the control computer to stop development of the master when the required pit volume has been reached. This ability to monitor developing as it happens makes it possible to compensate for differences between laser beam recorders and produce consistent pit geometry from master to master. The vacuum turntable enables final spin speeds of up to 1800 rpm for the Dual Density and 2500 rpm for the Universal Autodeveloper to be achieved. This, coupled with concentrated extraction, ensures a dry master and minimum BLER.

Both units feature online environmental monitoring. This ensures that a development cycle cannot be started if water temperature and resistivity are outside acceptable process conditions and protects the master from unnecessary damage. Data for each cycle is stored on the control computer and can be exported to text files for easy transfer to different data analysis applications.

Finished masters are consistent in terms of asymmetry and pit geometry.