Tempress Systems TS series horizontal diffusion and LPCVD furnace

Where the Tempress TS series fits

Tempress Systems is a Dutch furnace builder whose horizontal TS series is found in university cleanrooms, MEMS foundries and solar and power device lines across Europe. A stack holds several tubes, each configured for one process: wet or dry oxidation, boron or phosphorus diffusion, anneal, or LPCVD of polysilicon, nitride and oxide. A used Tempress diffusion furnace suits labs that need thermal oxide and LPCVD films of a quality that plasma tools cannot match.

Because each tube is an independent process module, the right used furnace is the one whose tubes match your process list. We describe every tube separately when we offer a stack. A typical four-tube research stack might hold:

• dry oxidation for gate and pad oxides
• wet oxidation for thick field oxide
• boron or phosphorus diffusion, or a nitrogen anneal
• LPCVD silicon nitride or polysilicon

Many stacks deviate from this, so treat it as a starting point rather than a standard. For the rest of the thermal range, see thermal processing equipment.

Tube by tube: what we inspect

For each tube we check:

• Temperature. Element resistance, zone balance and the length of the flat zone, measured with a profile thermocouple.
• Quartzware. Tube, end caps and boats for devitrification, cracks and deposit build-up.
• Gas system. Mass flow controllers, valves and leak integrity, including any bubbler or torch for wet oxidation.
• Vacuum (LPCVD). Base pressure, leak rate, pressure control and pump condition.
• Loading. Paddle or soft-landing drive, alignment and speed control.
• Controls. Tube controllers, host software, recipe storage and alarms.

Typical wear points are heating elements, thermocouples, quartz tubes on LPCVD positions, door and flange seals and drifting mass flow controllers.

Refurbishment and upgrades

We replace or reseat elements where needed, fit new thermocouples, clean or replace quartzware and leak test every gas line. LPCVD tubes receive pump service and pressure control calibration; see calibration for how we document temperature and flow checks. Certified tubes are run with test wafers and the oxide or film thickness and uniformity are in the report.

Common upgrades are a controller or host software update, new boats and quartzware for a wafer size conversion and dry pumps on LPCVD tubes. If you are choosing between LPCVD and plasma nitride, our post on PECVD vs LPCVD silicon nitride compares the two.

Facilities you will need

• Three-phase power with high current per tube, depending on element rating
• Cooling water for the furnace scavenger and vacuum pumps
• Clean dry air for valves and loading
• Nitrogen for purge and idle, often at high flow
• Process gases per tube, such as O2, H2, dichlorosilane, silane or ammonia
• Scavenger exhaust and, for LPCVD and doping, abatement
• Clean area for loading, with the frame often through-wall into a service chase

Buying advice

Map each tube to a process before buying, and plan for dedicated tubes where contamination matters. Check element and quartz condition, as both are significant costs. Make sure your building can deliver the power and exhaust: furnaces draw more current than most other tools in a small cleanroom.