Precursor and Dopant Delivery

Lorex offers its strong expertise and wide experience to customers within the fiber optics, photonics, semiconductor and other related industries in designing, fabricating, installing, upgrading and optimizing precursor and dopant delivery systems for advanced manufacturing processes.

Precursor and dopant delivery upgrade and optimization

Lorex engineers routinely perform technical audits of precursor and dopant delivery systems at customer facilities and offer specific recommendations on how to improve the performances of installed gas delivery systems. Improved control of precursor and of dopant delivery allows to meet ever more demanding process control and to make more cost-effective use of expensive chemicals.        

Example: silicon epitaxy process.
In this instance, Lorex engineers have been successful in improving wafer to wafer silicon epitaxy thickness reproducibility from 1– 1.5% down to .15% while at the same time minimizing the need for process re-qualification upon refilling the trichlorosilane (TCS) precursor tank and, in addition, allowing a more thorough use of the TCS tanks from full to virtually empty, therefore providing significant savings in the operation of the epitaxy process sector.

Example: Dopant delivery control.
In this case, Lorex engineers were instrumental in eliminating the effects of process drift due to changes in premix concentration over the life of the cylinder and process shift following cylinder swap out.  Piezocon control of dopant delivery eliminated the need to re-qualify the tools following a cylinder change, as well as eliminated the need to “chase” drifting premix concentration with periodic setpoint adjustments.  In addition, Lorex engineers implemented a very reliable technique for reducing by up to 85% the amount of dopant gases sent to vent, therefore saving thousands of dollars per month in operation cost.

Precursor delivery sub-systems
Besides its industry wide recognized Piezocon® gas concentration sensor, Lorex designs and manufactures an array of precursor delivery modules and systems that can be readily integrated into larger delivery systems. Representative examples of Lorex-designed and installed delivery modules and systems are shown below.

1. Integrated [Piezocon® sensor + MFC] module

Lorex integrated [Piezocon® + MFC] module has been designed and is built for high repeatability, reproducibility and stability delivery of precursors. Typical applications are delivery control of silicon and germanium precursors to CVD tools. The module is designed to replace failing and poorly supported Liquid Vapor Controller (LVC) modules and to guarantee a far more repeatable and reliable delivery control. In addition, the module provides a way to manage precursor delivery systems more cost-effectively by allowing very thorough use of the precursor chemicals and by minimizing tool re-qualification upon refilling or exchanging the chemical sources.

Piezocon® Sensor module for precursor delivery control to Piezocon® Sensor + MFC module for precursor delivery to CVD tools such as ASM Epsilon®.

2. Doping Gas Mixing Interface System

Lorex-designed and –built doping gas “Mixing Interface System” allows to dilute doping gases sourced from higher concentration premix tanks into lower concentration mixtures with very high precision and excellent reproducibility.
As an example, starting from a 1% DiBorane/H2 premix blend from a tank, Lorex Mixing Interface System can generate and deliver a 100 ± 0.5 ppm DiBorane/H2 “precision” dopant mixture to the process tool.
Besides achieving much tighter concentration control of the dopant gas mixture, by sourcing from higher concentration blend premix tanks, Lorex Mixing Interface System allows to reduce the frequency of the tank exchange, therefore providing very significant savings in operational cost of doping gas delivery.
The Mixing System has been designed as an interface that is conveniently installed between the premix tank and the gas delivery cabinet, therefore minimizing disruptive and costly modifications of the gas delivery system.

3. Precision gas blending systems

Making use of its Piezocon® gas concentration sensor, Lorex designs and builds gas blending systems for specific industrial or medical applications whenever precise and reproducible concentrations of gas mixtures are required.
Examples of precision gas blending applications are:

• H2 / N2
• CO / CO2 / N2
• Anesthetic gases

4. Precursor delivery systems

Tapping many years of experience with precursor delivery control, Lorex engineers have designed compact precursor delivery systems integrating a bubbler with the Piezocon® sensor and MFC. These systems provide very repeatable and reproducible delivery and cost-effective use of precursors. Most common applications are delivery of expensive precursors to MO-CVD tools.

System combining a bubbler with the Piezocon® Sensor for precursor delivery to CVD or MO-CVD tools.

5. Custom-designed delivery systems

Lorex engineers design and build customized precursor delivery systems that meet specific requirements and needs.