# US 5,760,405 A · Plasma chamber for controlling ion dosage in ion implantation

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- Number: US 5,760,405 A
- Document ID: US5760405A
- Status: Granted
- Kind: A
- Application number: 08/756,970
- Filed: 1996-11-26
- Granted: 1998-06-02
- Earliest claimed: 1996-02-16
- Assignees: Eaton Corporation
- Inventors: Michael C. King; Julian G. Blake; Peter H. Rose
- Web page: https://patentgrep.com/patent/US5760405A

## CPC

- H10P 72/0434: {mainly by convection}
- H01J 27/14: Other arc discharge ion sources using an applied magnetic field
- H01J 37/08: Ion sources; Ion guns
- H01J 37/18: Vacuum locks {; Means for obtaining or maintaining the desired pressure within the vessel}
- H01J 37/3002: {Details}
- H01J 37/3007: {Electron or ion-optical systems}
- H01J 37/304: Controlling tubes by information coming from the objects {or from the beam}, e.g. correction signals
- H01J 37/3171: {for ion implantation}
- H10P 72/0421: {for drying etching}
- H10P 72/3306: {Horizontal transfer of a single workpiece}
- H10P 72/3308: {Vertical transfer of a single workpiece}
- H10P 72/3411: {involving loading and unloading of wafers}
- H10P 72/78: using vacuum or suction, e.g. Bernoulli chucks
- H01J 2237/022: Avoiding or removing foreign or contaminating particles, debris or deposits on sample or tube
- H01J 2237/083: Beam forming
- H01J 2237/184: Vacuum locks
- H01J 2237/2001: Maintaining constant desired temperature
- H01J 2237/2007: Holding mechanisms
- H01J 2237/20228: Mechanical X-Y scanning
- H01J 2237/204: Means for introducing and/or outputting objects
- H01J 2237/31701: Ion implantation
- H01J 2237/31705: Impurity or contaminant control
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

An ion source for generating an ion beam of primary ions is disclosed that includes a plasma chamber and magnets positioned therein for separating the primary ions of the plasma from secondary ions within the plasma. An electrode assembly extracts the primary ions through an extractor outlet port of the plasma chamber to form an ion beam, which preferentially is shaped as a ribbon beam. The primary ions are accelerated in the form of a ribbon beam toward the target workpiece for doping the device. The magnets are oriented in the chamber to produce a uniform current density of primary ions parallel to the elongated axis of the ribbon beam.

## Claims

### Claim 1

Apparatus for controlling the extraction of an ion beam from a plasma having a mixture of primary ions and secondary ions, said apparatus comprising:
a chamber for enclosing said plasma, said chamber having an outlet port,
a magnetic field generating means for separating said primary ions from said secondary ions within said chamber, and
an extractor coupled to said outlet port for forming a ribbon shaped ion beam elongated along a first axis,
wherein said extractor cooperates with said magnetic field generating means to extract a ribbon shaped ion beam of the primary ions the ribbon shaped ion beam having reduced non-uniformities.

### Claim 2 (depends on 1)

The apparatus of claim 1 wherein said magnetic field generating means generates a magnetic field parallel to said first axis.

### Claim 3 (depends on 2)

The apparatus of claim 2 wherein said magnetic field generating means comprises a plurality of permanent magnets arranged such that the north pole of one magnet is adjacent to the south pole of a second magnet.

### Claim 4 (depends on 1)

The apparatus of claim 1 wherein said magnetic field generating means is enclosed by said chamber.

### Claim 5 (depends on 1)

The apparatus of claim 1 wherein said secondary ions are hydrogen ions.

### Claim 6 (depends on 1)

The apparatus of claim 1 wherein said primary ions are P.sup.+ ions.

### Claim 7 (depends on 1)

The apparatus of claim 1 wherein said chamber is encompassed by a plurality of magnets for reducing the plasma interaction with the wall of the chamber.

### Claim 8

An apparatus for controlling the extraction of an ion beam from a plasma having a mixture of primary ions and secondary ions, the apparatus comprising:
a chamber for enclosing the plasma, the chamber having an outlet port,
an extractor coupled to the outlet port for forming a ribbon beam of ions extending along an axis of elongation, and
a magnetic field generator forming a magnetic field extending substantially parallel to the axis of elongation, the magnetic field acting to separate the primary ions from the secondary ions within the chamber,
wherein the extractor cooperates with the magnetic field generator to extract a ribbon beam of primary ions.

### Claim 9 (depends on 8)

The apparatus of claim 8 wherein the magnetic field generator comprises a plurality of permanent magnets arranged such that the north pole of one magnet is adjacent to the south pole of a second magnet.

### Claim 10 (depends on 8)

The apparatus of claim 8 wherein the magnetic field generator is enclosed by the chamber.