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Nanchong Xichong vacuum equipment

Vacuum equipment does more than remove air. It creates pressure, cleanliness and gas conditions for semiconductor coating, heat treatment, nuclear work or space simulation. Pumps set speed and ultimate pressure, chambers and valves hold the boundary, and controls determine state; Xichong integrates these parts into systems.

Formation and regional foundations

Jiutian built experience in environmental-simulation systems, Yutian supplies valves, chambers and standard parts, and Zhongke Jiuwei enters dry pumps and semiconductor process equipment. Local planning also calls for metrology and inspection, turning the “Vacuum Valley” concept into component, system and test roles.

Target pressure is only a start. Process gas, outgassing, particles, oil backstreaming, valve conductance and gauge location all change the chamber. Xichong has pumps, chambers, standard parts and systems, making it possible to follow a complete pumping path rather than compare ultimate pressure alone.

Core geography: A vacuum-equipment network around Duofu Industrial Park and Nanchong equipment areas, joining dry pumps, valves and standard parts, chambers, measurement and control, leak testing and environmental-simulation systems

Five stations taking a vacuum target into a process chamber

How pumps, valves, chambers and gauges constrain one another in Xichong

The application sets gas load and cleanliness; chamber and valves establish boundary, pumps act through conductance, and gauges and controls determine state. Leak and maintenance findings can return to a seal, pump stage or sensor instead of blaming the main pump generically.

  • Process pressure and cleanliness — Gas, temperature, particles and cycle define system duty.
  • Chamber, valves and seals — Volume, material and leak rate establish the boundary.
  • Roughing and high-vacuum pumps — Pump type, stages and gas load determine pumping behaviour.
  • Measurement, control and leak test — Gauge location, range and interlock turn pressure into action.
  • Coating and simulation station — Actual process exposes outgassing, contamination and cycle time.

01 · Process duty is more than pressure

Cleanliness, gas load, temperature and cycle define vacuum.

Usable vacuum is defined by a particular process and cannot be reduced to the ultimate pressure on a nameplate. Semiconductor, coating, heat treatment and environmental simulation tolerate different cleanliness, process-gas, material-outgassing and pumpdown conditions, so an empty chamber reaching low pressure does not prove that it can run with a workpiece. An Xichong system team must describe the full cycle, load materials and permitted residual gases before selecting chamber, pump train and measurement arrangement. Fixtures, seals and exposed processing area also belong in the gas-load inventory and require cleaning and prebaking with the workpiece. Pumpdown rhythm changes when the loading arrangement alters exposed area.

When an empty chamber reaches pressure but cannot run after the specimen enters, added gas load or process flow has changed the pumping balance. Investigation compares empty and loaded curves separately, aligning specimen material, chamber-wall temperature, gas-admission time and residual-gas change. If water or organic peaks appear with the specimen, material outgassing and pretreatment deserve attention; if the pressure range stalls after gas admission, flow configuration and pump capacity require review.

The system duty sheet lists loading, pumpdown, hold, gas admission, treatment and venting in sequence, including workpiece material, cleanliness requirement and allowed cycle. A representative workpiece runs through the complete program, with empty-loaded curves, residual gas and process-side outcome retained separately rather than replaced by one ultimate-pressure value. The chamber and pump combination is suitable after the loaded cycle reaches its process window consistently within the specified time.

  • Applications tolerate backstreaming and particles differently.

02 · Chamber materials continue to outgas

Welds, finish and cleaning determine the vacuum boundary.

A vacuum chamber encloses process space with plate, welds, flanges and feedthroughs, and those surfaces and joints can release or admit gas during pumpdown. Adsorbed water and cleaning residue create continuing outgassing, weld porosity may communicate with atmosphere, and trapped volumes behave as slowly releasing virtual leaks. Mechanical pressure integrity establishes a structural boundary, while clean high vacuum also requires controlled surfaces, sealed interfaces and bakeability. Blind threaded holes and layered seals can trap small gas volumes as well.

When late pumpdown stalls, contamination rises after bake or a local helium response appears, adding pump speed alone rarely removes the cause. Helium seeks an atmospheric path, the residual-gas spectrum identifies water and process residue, and zoned heating shows which surface releases gas. Once those observations have coordinates, the team can choose repair welding, seal correction or renewed cleaning without forcing different mechanisms into one repair.

Chamber material, weld form and feedthrough design follow cleanliness class, bake temperature and cleaning frequency, with post-weld treatment included in the manufacturing route. Leak rate, pumpdown curve and residual-gas change are measured before cleaning, after cleaning and during bake, while helium responses retain weld-zone and flange coordinates. A vacuum boundary is manufacturable and durable only if original gas load and leak rate return after maintenance.

  • Thick or strong material cannot replace low outgassing and cleanability.

03 · Valves and piping limit effective speed

Conductance translates pump-port performance to the chamber.

The chamber reaches its vacuum pumps through valves, elbows, straight pipes and filter baffles, and that path translates pump-port capacity into effective speed near the workpiece. A smaller bore, longer route or partly closed valve increases conductance loss, with the difference between a short wide path and a long narrow one becoming especially pronounced in molecular flow. Using the pump nameplate directly overestimates system performance and does not explain a slow pressure range. If Xichong system design leaves the piping bottleneck untouched, a larger main pump only adds cost and load.

When a larger pump barely changes pumpdown or one pressure range remains slow, pressures should be compared along the pumping path. Pipe size, valve position, flow regime and gas-load source need review, with the relevant viscous, transitional or molecular-flow regime identified. Comparing pump-port and chamber pressure, valve state and calculated conductance locates the restriction in a valve, long pipe or actual gas load instead of treating a larger pump as the universal answer to slow pumpdown.

Pipe bore, length, elbows, valves and baffles are first sized for target gas flow and pressure range, then selected together with the pump operating envelope and available installation space. Commissioning measures the pump port, main line and chamber, comparing sectional pressure drops, valve position and pumpdown curve to locate the dominant loss. Increasing nameplate pump capacity has practical meaning only after effective speed meets cycle duty and the structural bottleneck is understood.

  • Small bores, long pipes and baffles create bottlenecks.

04 · Pump trains cover the full pressure range

Roughing, dry and high-vacuum pumps cover different ranges.

A vacuum train commonly combines a backing pump, booster and high-vacuum stage across different pressure ranges, and each remains stable only under suitable inlet conditions. Switching too early overloads the downstream stage, switching too late lengthens the cycle, and backing exhaust pressure can narrow the upstream operating range. Process gas, dust and corrosion continue to alter temperature, clearance and exhaust condition, so empty ultimate pressure cannot represent continuous production. A complete system must describe startup, handover, shutdown and abnormal recovery together.

When interstage overload, heat, reverse flow or deposits appear, the cause may lie in switching logic rather than damage to one pump stage. Engineers align switch pressure, backing capacity, purge and exhaust backpressure with current-temperature trends to see whether the event began before or after handover. An inlet-pressure excursion points to poor switching timing, whereas a gradual rise in exhaust resistance is more consistent with deposits or piping.

Process gas, particle load and target pressure determine the combination of backing, booster or high-vacuum pumps, including interstage protection and purge. Integrated tests cover startup, stable processing, normal shutdown and abnormal recovery while synchronising current, temperature, inlet pressure and exhaust condition for every stage. The train has full-cycle capability when handover creates no overload, contamination backflow or uncontrolled pressure.

  • Stage switching and process gas determine the combination.

05 · Dry pumps still manage by-products

Oil-free does not mean immune to corrosion, dust or condensation.

A dry vacuum pump keeps oil out of the pumping chamber but directly encounters corrosive gases, dust, polymers and condensed by-products. These materials can alter rotor clearances, temperature zones and exhaust resistance, gradually raising current, reducing speed or shortening service intervals, none of which is represented by clean-air performance. Pump type, materials, purge and temperature control must follow the process recipe and be confirmed through deposit examination during service. Condensation at a cold exhaust section can create a blockage outside the pump chamber.

When pump current rises gradually, the exhaust blocks or the service interval shortens, trends usually appear before the final alarm. Operating hours are aligned with process recipes before purge flow, temperature zones and pumpdown time are compared, and teardown locates deposits in the chamber, exhaust or cold end. Accumulation after a particular recipe may respond to purge or temperature changes, whereas a uniform time-based burden calls for a different cleaning interval.

Internal materials, purge flow and temperature zones are set from process gas and expected deposit location, with measures for condensation in the exhaust line. A representative recipe runs through a planned service interval, trending current, temperature and pumpdown time before deposits are weighed and located at teardown. The dry-pump configuration fits production rhythm when performance decay and cleaning interval are both predictable.

  • Purge, temperature and cleaning cycle are process configuration.

06 · Gauge position determines the reading

Range, gas sensitivity and location affect pressure interpretation.

Measurement from rough to high vacuum requires gauges with different physical principles to hand over across ranges, because one instrument rarely covers the whole span. Gas species, contamination and temperature alter sensitivity, while location and valve state create local pressure differences, so a controller number may not equal conditions near the workpiece. Gauge types should agree in their overlap, and the critical measurement point must correspond to the actual control purpose. Moving the same gauge across a valve can change the control decision.

If two gauges diverge or process results disagree with displayed pressure, choosing whichever instrument matches expectation only hides the difference. A reference gauge first checks the overlap, then valve position and flow are changed to see whether the deviation stays with one instrument or one location. A recipe-dependent shift may require gas-sensitivity correction, a fixed zero drift points to calibration or contamination, and a local pressure difference returns attention to piping.

Gauge range and physical principle follow the control objective, with the key point near the process zone but away from heavy deposition or strong local pressure drop. Overlapping ranges are compared with a reference gauge, while gas correction, calibration date and cleaning history remain tied to instrument identity and interlocks are exercised under actual flow. A reading becomes a reliable control variable after it consistently drives valves and pumps and explains workpiece condition.

  • The displayed value may not equal the state near the workpiece.

07 · Leak testing separates leaks and outgassing

Helium testing, hold and rise tests answer different questions.

A vacuum boundary may communicate with atmosphere through welds, seals, stems or feedthroughs, while material outgassing and trapped volumes also raise pressure. An external leak has a real path, a virtual leak comes from an enclosed space, and surface outgassing responds to cleaning and temperature, requiring different remedies. Helium testing, pressure-rise work and residual-gas analysis examine location, release rate and gas composition respectively, so one result cannot replace the full diagnosis. A path from weak seal compression is not the same phenomenon as slow release from a material surface.

Unstable hold pressure, a local helium response or abnormal post-bake pressure can first be separated by response speed and temperature dependence. If local helium repeatedly creates a peak through the same path, an external leak is more likely; slow release after heating with a matching gas spectrum directs attention to a trapped volume or surface. Once classified, the team can tighten an affected flange, open a virtual volume or reclean without reworking the entire chamber indiscriminately.

The leak plan divides welds, flanges, stems and feedthroughs according to chamber structure, assigning a method and allowable rate to each zone. During assembly, cleaning and bake, helium response, pressure rise and residual-gas composition are used together, and any disassembly returns inspection to the affected coordinate. Repair reaches the correct location after an anomaly is separated into external leakage, trapped-volume virtual leakage or material outgassing.

  • One method cannot cover every leak source alone.

08 · Application cycles determine maintenance design

Coating deposits, seal ageing and pump contamination accumulate.

Vacuum equipment vents, opens, cleans and pumps down again after each process, while deposits, seal compression and pump by-products accumulate with cycles. Initial acceptance describes only the new-machine state, and pumpdown, particles and cleanliness months later depend on whether maintenance restores critical interfaces. Reachable cleaning areas, repeatable reassembly datum and practical replacement time are therefore part of system capability rather than matters added after delivery. How contamination is removed and contained also determines the downtime required for one service.

When pumpdown slows, particles increase or service fails to restore baseline, the change must be matched with accumulated cycles and the latest work. Baseline curves show when performance departed, leak-rate checks examine interfaces, and process-defect trends reveal whether cleanliness has reached the product. A sudden deviation after reassembly calls for a service correction, whereas gradual movement with deposits is better addressed through cleaning windows and wear-part intervals.

During design, tool access is reserved for chamber cleaning, pump removal, gauge calibration and wear-seal replacement, with reassembly datum specified. After commissioning, every planned service is followed by the same representative cycle, comparing pumpdown, leak rate, cleanliness and product defects before and after work. The maintenance arrangement supports equipment life and stable production when the system recovers its baseline within permitted downtime.

  • Maintainability is part of system capability.

Sources and reading notes

Start from process pressure, cleanliness, gas load and cycle time, then examine chamber volume, leak rate, conductance, pumps, gauges and controls. Semiconductor, coating, nuclear and space-simulation duties need different materials and safety boundaries and cannot be selected by the phrase “high vacuum.”

  • The municipal industrial review confirms the national cluster and dry-pump and environment-simulation directions.
  • A county report names Jiutian and Yutian and their valves, chambers and equipment.
  • The equipment plan identifies PVD and CVD vacuum equipment plus metrology and inspection.
  • A provincial enterprise list confirms Sichuan Jiutian Vacuum Technology’s legal name.

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Sources

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