LGO Heating Element for Tube Furnaces

JTEKT Thermo Systems is represented in Europe by
Crystec Technology Trading GmbH

LGO Heating Element for Tube Furnaces

JTEKT Thermo Systems (formerly Koyo Thermo Systems) produces Light Gauge Overbend (LGO) heating elements, but can also supply Heavy Gauge Coil (HGC) heaters.

Light Gauge Overbend (LGO) Heating Elements

LGO Heating Elements with Low Thermal Mass and High Stability

JTEKT's patented LGO heating elements feature a special construction. Thin heating wires are cast into a ceramic mass, leading to a quick response time and temperature adjustment. The low heat capacity of the thin wires allows rapid heating and cooling, while fixation in the ceramic ensures high stability and durability. These heating elements are particularly suitable for operation at low temperatures from 120°C and for temperatures up to 1150°C.

The meandering arrangement of heating wires in the heating zone prevents the formation of a magnetic field in the heater, which can occur with a typical coil arrangement and may interfere with certain processes or other electronic devices. Compared to conventional heating elements, LGO heating elements require fewer heating zones, resulting in comparatively lower power consumption. The outstanding temperature uniformity results in an extended flat zone and a uniform radial temperature distribution.

Features of LGO Heating Elements

  • Outstanding temperature uniformity
  • Rapid heating and cooling compared to standard heating elements
  • Effective and precise temperature control at low temperatures (from 120°C)
  • Avoidance of overshooting at the end of heating ramps
  • No magnetic field within the heating element
  • High durability and extended lifespan
  • Up to 40% power savings per run compared to standard heating elements

LGO performance semiconductor heater

Heavy Gauge Coil (HGC) Heating Elements

HGC Heating Elements with High Thermal Mass

As an alternative to the LGO heaters, JTEKT Thermo Systems offers conventional heaters for applications that require particularly high temperatures in semiconductor furnaces. These are mostly oxidation processes. The maximum operating temperature is 1300°C.

HGC conventional semiconductor heater

Comparison of LGO and HGC Heating Elements
Temperature Range 120°C-1150°C 400°C-1300°C Suitable for Polyimide Cure Excellent Good
Heat Capacity Low High Suitable for Hydrogen Anneal Excellent Good
Weight Low High Suitable for SOG Anneal Excellent Good
Stability High Good Suitable for Doping Good Good
Heating Wire Arrangement Meander Coil Suitable for Oxidation Good Good
Heating Rates Fast Normal Suitable for High-Temperature Oxidation - Good
Cooling Rates Fast Normal Suitable for LP Oxide Good Good
Temperature Accuracy Very High High Suitable for LP Nitride Good Good
Prevention of Overshoot Very Good Normal Suitable for LP Polysilicon Good Good

Our LGO heaters exhibit a very uniform radial temperature distribution. This ensures a consistent temperature treatment across the entire surface of the wafer.

radial temperature distribution

Comparing JTEKT Thermo Systems' LGO heater with conventional heating elements, it is evident that the LGO heater responds much faster to control commands. This can almost completely eliminate temperature overshooting at the end of heating phases. This is especially true for so-called "low-temperature processes" such as Polyimide curing, hydrogen tempering, or SOG:

Temperature overshoot behavior of LGO heater

It is also possible to retrofit LGO heating elements for already installed furnaces.