US 4,607,167 AGranted

Charged particle beam lithography machine incorporating localized vacuum envelope

AssigneeVarian Associates, Inc.

InventorPaul F. Petric

Life of this patent

Estimating the term…

Loading patent…

Abstract

A charged particle beam lithography machine includes a beam source and beam steering and forming elements within an evacuated column. A stage assembly for supporting a semiconductor wafer or mask is positioned in ambient and proximate the exit end of said beam steering and forming elements. A vacuum envelope apparatus is affixed to the exit end of the beam steering and forming elements so that the outer surface or tip of the vacuum envelope apparatus rests in spaced apart, close coupled opposition to the wafer or mask supported on the stage. The vacuum envelope apparatus includes internal structural members which define an internal vacuum processing zone and at least one surrounding intermediate vacuum zone. A graded vacuum seal is formed between the tip of the vacuum envelope and the mask or wafer. The seal extends from the internal vacuum processing zone to the external ambient. Lithographic operations are conducted on the mask or wafer as relative motion between the stage assembly and the beam steering and forming elements is accomplished.

Claims13

Dependent claims

Charged particle beam lithography apparatus for treating a semiconductor wafer or a mask workpiece surface comprising a vacuum envelope having an aperture, a charge particle beam source located in the vacuum envelope for deriving a charged particle beam that is directed through the aperture as a treating beam for the workpiece surface, means for deflecting the charged particle beam while it is in the envelope, means for maintaining only a portion of the workpiece surface in approximate registration with the aperture in a vacuum such that the beam can propagate from the source to the workpiece surface portion exclusively in a vacuum, said maintaining means including:

(a) means for holding the workpiece so that all of the workpiece except said workpiece surface portion is in an ambient environment not subject to the vacuum;
(b) means for preventing contact between the envelope and the workpiece so that a gap is formed between the workpiece surface and the envelope whereby the workpiece surface can move generally transversely of the beam propagation direction to enable portions of the workpiece surface to be treated in vacuo by the beam at differing times, and (c) vacuum pump means foring a graded vacuum seal in the gap generally transversely of the beam propagation direction for minimizing degradation of the vacuum through the gap;
means for controlling the length of the gap to a predetermined range without contacting the workpiece;
and means for providing a curtain of clean gas at approximately atmospheric pressure completely surrounding the vacuum in the gap for substantially preventing atmospheric air and contaminants therein from entering the vacuum in the gap and envelope, the envelope including a tip having a central passage defining the aperture and a concentric passage connected to the vacuum pump means for forming the graded vacuum seal, the tip terminating in a plane forming one side of the gap, the passages terminating at said plane, at least one of the passages having a cross-sectional area that increases as the distance of said one passage increases from said plane.

1 more element

A method for charged particle beam lithography treatment of a semiconductor wafer surface comprising the step of:

directing a beam from a source located in a vacuum envelope through an aperture in a vacuum tip of the envelope onto a first portion of the wafer surface that is approximately in registration with the aperture;
maintaining a gap between the vacuum tip and the first portion of the wafer surface sufficient to prevent any contact between the wafer surface and the vacuum tip;
maintaining the first portion of the wafer surface in vacuum while maintaining the remainder of the wafer surface in an ambient environment outside of the vacuum, the vacuum being formed by using vacuum pump means to form a graded vacuum seal in the gap while the first portion of the wafer surface is being treated by the charged particle beam, providing high vacuum conductance between the vacuum pump means and the vacuum tip through passage which increase in cross-sectional area as the distance from the tip increases, and maintaining the area of the aperture and the first portion of the wafer surface maintained in vacuum sufficiently small relative to the wafer surface area to permit treatment close to the edge of the wafer surface without loss of the vacuum in the gap and to minimize wafer bowing caused by the differential pressure across the wafer;
moving the wafer surface relative to the aperture so that different portions of the surface are successively in registration with the aperture while (a) maintaining the gap between the wafer surface and the aperture (b) maintaining said relationship between aperture area and the wafer surface area and without (c) breaking the vacuum seal between the workpiece surface and the vacuum envelope interior so as to treat selected portions of the wafer surface;
and
substantially preventing atmospheric air and contaminants therein from entering the vacuum in the gap and the envelope by providing a curtain of clean gas at approximately atmospheric pressure completely surrounding the vacuum in the gap between the wafer surface and the vacuum envelope interior.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/701,439Filed 12 Feb 1985 · continuation
Priority: 19 Oct 1982
Granted: 19 Aug 1986
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H01J 37/3174
For changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation: particle-beam lithography, e.g. electron…
B82Y 10/00
Nanotechnology for information processing, storage or transmission
B82Y 40/00
Manufacture or treatment of nanostructures
H01J 37/301
Electron-beam or ion-beam tubes for localised treatment of objects: arrangements enabling beams to pass between regions of different pressure