| Description | Horizontal furnace (e.g. M206) | Vertical furnace Production (e.g. VF5300) | Vertical furnace R&D (e.g. VF1000) |
|---|---|---|---|
3- or 4-tube Horizontal furnace
e.g. model M206 |
Vertical furnace for production
e.g. VF5300 |
Vertical furnace for R&D
e.g. VF1000 |
|
| Ramp-up rate | slower | faster | faster |
| Loading time for quartz boat | slower | faster | faster |
| Cooling speed | same | same | same |
| Max. temperature when using LGO heating elements | 1100°C | 1250°C | 1250°C |
| Temperature uniformity | lower | higher | higher |
| Mutual influence between tubes | 1 - 2 °C | no | no |
| Oxygen concentration in the center of the tube (end open) | 16% | 0.1% | 0.1% |
| Oxygen concentration at tube end (end open) | high | 500 ppm | 500 ppm |
| Oxygen concentration in the center of the tube (end closed) | 0.1% | 300 ppm | 300 ppm |
| Oxygen concentration at tube end (end closed) | 10 - 30 ppm | 10 ppm | 10 ppm |
| Gas-tight process chamber (atmospheric process) | no | yes | yes |
| HCl leak tightness | no | yes | yes |
| Mutual contamination | possible | not possible | not possible |
| Process independence | not entirely | yes | yes |
| Particle levels | worse | very good | better |
| Flexibility: Different wafer diameters in one run | possible | not possible | not possible |
| Flexibility: Different wafer diameters across different runs | possible | not possible | possible |
| Flexibility: Supported wafer diameters | 3" - 6" (8") | 4" - 300 mm | 3" - 300 mm |
| Wafer cassette loading | no | yes | no |
| Level of automation | lower | very high | higher |
| Film thickness uniformity wet oxidation 10 nm, 8" wafer | no data | ± 0.9 % | ± 0.9 % |
| Film thickness uniformity dry oxidation 20 nm, 8" wafer | ± 2.4 % | ± 1.2 % | ± 1.2 % |
| Film thickness uniformity poly-silicon 400 nm, 8" wafer | ± 2.0 % | ± 1.0 % | ± 1.0 % |
| Film thickness uniformity nitride 100 nm, 8" wafer | ± 2.5 % | ± 1.5 % | ± 1.5 % |
| Capacity | >150 wafers | 100 - 150 wafers | 25 wafers |
| Power consumption | higher | lower | very low |
| Maintenance independence of tubes | no | yes | yes |
| Required maintenance | more | less | very little |
| Footprint per tube | 2.6 - 3.4 m2 (partly in cleanroom) | 3.0 m2 (grey room) | 1.5 m2 (grey room) |
| Price | low | high | low |
Comparison of Vertical and Horizontal Furnaces
We are often asked about the differences between vertical furnaces and horizontal furnaces and why vertical systems are more expensive. For this reason, the following presentation outlines the differences between the various types of equipment. We hope that this overview and the comparison of data and facts will help you with your planning.
For the vertical furnaces we have included a production system (VF5300) as well as our small vertical furnace VF1000, which is particularly a good alternative to horizontal furnaces for smaller companies and research institutes.
Comparison of Furnace Features
Further Information & Conclusion
Today, mass production of semiconductor chips is performed on 200 mm and 300 mm silicon wafers. Vertical furnaces are used almost exclusively. Horizontal furnaces are still found only in older fabs that use smaller wafers or for a few special applications. For wafer sizes up to 6" they are often still sufficient to meet customer requirements, but the advantages of vertical furnaces are obvious even for 6" wafers.
This market situation has led to the development of horizontal furnaces being discontinued by most major furnace manufacturers. Development now takes place almost exclusively in the field of vertical furnaces. As a result, vertical systems not only have a physical advantage but also represent the modern production tool and therefore deliver significantly higher performance.
For smaller companies, pilot lines, research institutes and universities this development has the drawback that high performance is coupled with a high level of automation and thus high cost. For budget reasons, the purchase of a significantly cheaper horizontal furnace is often the only option, even though this choice requires accepting clear process disadvantages.
JTEKT Thermo Systems (formerly Koyo Thermo Systems) has offered a solution for these customers for several years. JTEKT developed a small vertical furnace called VF1000 specifically for this market. The VF1000 is a fully fledged vertical furnace with full process capability. Since throughput requirements for research customers are often low, the furnace was implemented as a mini-batch system. The load is 25 wafers (standard) or 50 wafers (option). Loading is manual, which greatly increases system flexibility. All further steps, such as inserting the boat into the furnace and executing process recipes, are fully automated as in production systems. The price is only slightly higher than alternatively offered horizontal furnaces.
The footprint required for such small vertical furnaces is actually smaller than for the same number of installed horizontal tubes. Here we show, as an example, the layouts of 12 tubes implemented with VF1000 systems and with Horizontal furnaces, type 208 (3 tubes per stack).
JTEKT Thermo Systems manufactures numerous versions of vertical furnaces and horizontal furnaces with fully automatic and manual operation. Small versions for pilot lines and research institutes are available.
JTEKT Thermo Systems and Crystec look forward to providing you with a cost-effective system that meets your most demanding requirements.