# US 12,110,896 B2 · Axial flow vacuum pump with curved rotor and stator blades

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- Number: US 12,110,896 B2
- Document ID: US12110896B2
- Status: Granted
- Kind: B2
- Application number: 17/904,143
- Filed: 2021-02-10
- Published: 2023-04-06
- Granted: 2024-10-08
- Earliest claimed: 2020-02-13
- Assignees: Edwards Limited
- Applicants: Edwards Limited
- Inventors: Nigel Paul Schofield; Stephen Dowdeswell
- Web page: https://patentgrep.com/patent/US12110896B2

## CPC

- F04D 19/042: {Turbomolecular vacuum pumps}
- F04D 19/048: {comprising magnetic bearings}
- F04D 29/32: for axial flow pumps
- F04D 29/324: {Blades}
- F04D 29/38: Blades {(for axial flow compressors F04D29/324)}
- F04D 29/384: {characterised by form}
- F04D 29/542: {Bladed diffusers (fixing blades to stators F01D9/042)}
- F04D 29/544: {Blade shapes}
- F05D 2250/71: curved
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

An axial flow vacuum pump for evacuating a chamber in a semiconductor manufacturing process comprises a rotor having a plurality of rotor blades and a stator having a plurality of stator blades, wherein the rotor blades and stator blades have a curved shape.

## Claims

### Claim 1

An axial flow vacuum pump for evacuating a chamber in a semiconductor manufacturing process, the axial flow vacuum pump comprising:
a rotor having a plurality of rotor blades; and
a stator having a plurality of stator blades, wherein the rotor blades and stator blades have a curved aerofoil cross-sectional shape comprising a curved leading edge, a pointed trailing edge, a concaved pressure surface extending from the leading edge to the trailing edge and a curved suction surface extending from the leading edge to the trailing edge, wherein the concaved pressure surface of each rotor faces in a direction of rotation of the rotor;
wherein an inlet stage of the pump comprises blades having a first radial length and an adjacent downstream stage of the pump comprises blades having a second radial length, wherein the ratio of first radial length to second radial length is 2:1 or greater.

### Claim 2 (depends on 1)

The axial flow vacuum pump of claim 1, wherein the rotor is supported for rotation relative to the stator by magnetic bearings.

### Claim 3 (depends on 1)

The axial flow vacuum pump of claim 1, wherein the rotor is formed from stainless steel.

### Claim 4 (depends on 1)

The axial flow vacuum pump of claim 1, comprising between 4 and 10 pumping stages, each pumping stage comprising a row of rotor blades and a row of stator blades.

### Claim 5 (depends on 1)

The axial flow vacuum pump of claim 1, comprising a bypass conduit for directing a portion of a gas from an outlet of the pump towards the inlet stage of the pump.

### Claim 6 (depends on 5)

The axial flow vacuum pump of claim 5, wherein the bypass conduit comprises a pressure relief valve.

### Claim 7 (depends on 1)

An apparatus for manufacturing semiconductor equipment comprising:
a chamber for manufacturing semiconductor equipment in;
a backing pump system positioned remote from the chamber and configured to evacuate gas from the chamber;
a foreline for fluidly connecting the backing pump system to the chamber; and
an axial flow vacuum pump according to claim 1 configured to evacuate the gas from the chamber, wherein the axial flow vacuum pump is connected between the chamber and foreline.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the axial flow vacuum pump is positioned less than 2 meters from the chamber.

### Claim 9 (depends on 7)

The apparatus of claim 7, wherein the backing pump system is positioned more than 8 meters from the chamber.

### Claim 10 (depends on 1)

A method of evacuating a semiconductor equipment fabrication chamber comprising:
using an axial flow pump as described in claim 1 to evacuate gas from the chamber;
operating the axial flow vacuum pump to pump the gas with a pressure of 1 mbar or higher;
operating the axial flow vacuum pump to pump the gas with a pressure of between 1 mbar and 0.001 mbar; and
operating the axial flow vacuum pump to pump the gas with a pressure of 0.001 mbar or lower.

### Claim 11 (depends on 10)

The method of claim 10, comprising using a backing pump to evacuate the gas from the chamber, the backing pump system being positioned remotely from the chamber and the axial flow vacuum pump.

### Claim 12 (depends on 10)

The method of claim 10, wherein the axial flow vacuum pump is positioned less than 2 meters from the chamber.

### Claim 13 (depends on 10)

The method of claim 10, comprising the axial flow vacuum pump to pump the gas at a temperature of 130 degrees Celsius or higher.