Oxford Instruments Plasma Technology (OIPT) has been a leading provider of high volume batch plasma tools in the production market for more than 15 years, with a broad installed base of HBLED production systems in operation.
PlasmaPro NGP1000 Production Platform
High Brightness LEDs (HBLEDs) are quickly replacing conventional light sources in a number of applications that include TV and laptop screen backlighting and even general lighting as HBLEDs deliver a highly effective light source in a compact package with a very long lifetime. The huge demand for LEDs requires production equipment with a high throughput. Gallium Nitride (GaN) etching is a major part of the HBLED production process.
OIPT has developed a batch tool for GaN etching that depends on the PlasmaPro NGP1000 production tool platform. This tool utilises the newly introduced Viper plasma source that provides superior uniformity over large areas.
By delivering power in the VHF band, this source provides a high plasma density, which can be compared with current OIPT ICP sources and maintains the advantages of high etch rates but in a low damage environment. The plasma source chamber components and hardware have been designed very carefully such that while electromagnetic effects are reduced to a minumum when operating at VHF.
This reduces non-uniformities and asymmetries that reduce the efficiency of the process across a batch of wafers.
Carrier can accommodate up to 61 x 2” wafers
Configurable to accommodate up to 7 x 6” wafers
The design parameters are now well defined and can be fine-tuned to meet specific process requirements. A GaN etching process has been designed that offers:
- 55 x 2” wafer batch etching rates in excess of 140nm/min
- Selectivity to photoresist ~1:1, and
- Uniformities wafer-to-wafer and across-wafer <±5%.
Etched surfaces are found to be smooth across the whole batch and across many runs. The process has been transferred successfully to the OIPT’s newly opened Far East Applications Laboratory present at ITRI, Taiwan, in readiness for customer demonstrations.
||Number of wafers
||Clamped and He cooled etch
The figure shows the SEM image of the etched GaN surface near a masked edge, (photoresist removed)
SEM image of the etched GaN surface near a masked edge, (photoresist removed)
Oxford Instruments – Expansion Plans
The company has introduced a major expansion and improvement program at Oxford Instruments. Plasma Technology is delivering major benefits to customers. Investment in a number of areas of the business has caused quicker and more streamlined manufacturing, superior research facilities and more comprehensive customer support.
According to the MD of Oxford, the workforce has expanded by 30% in the previous one year enabling them to respond rapidly to customer orders and offer process and product development for our customers. The company has included parallel build and test bays in manufacturing for manufacture of its etch, deposition and growth equipment, offering more flexibility to respond to customer requirements, and minimising manufacturing lead times.
This has resulted in more effective manufacturing processes for repeat products in supplying equipment to the quickly expanding HBLED production market.
This information has been sourced, reviewed and adapted from materials provided by Oxford Instruments Plasma Technology.
For more information on this source, please visit Oxford Instruments Plasma Technology.