SUBSTRATE EARTHING MECHANISM FOR USE IN CHARGED-PARTICLE BEAM WRITING APPARATUS

Abstract

A substrate earthing mechanism includes a plate-like spring extending toward a substrate in a direction parallel to a surface of the substrate, and a contact portion coupled to a tip end of the plate-like spring for coming into contact with the substrate to thereby provide electrical conduction therebetween. The plate spring and the contact portion are laid out so that a contact position at which the contact portion is in contact with the substrate and a layout position of the plate-like spring are substantially the same in position as each other in a direction at right angles to the substrate surface in the state that the plate spring is out of its elastic deformation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing an overall arrangement of an electron-beam lithography apparatus in accordance with one embodiment of the present invention.

FIG. 2 is a top plan view of part of a substrate earthing mechanism used in the lithography apparatus of FIG. 1.

FIG. 3 is a side view of main part of the substrate earthing mechanism.

FIG. 4 is a plan view of one exemplary substrate in the EB lithography apparatus.

FIG. 5 is an enlarged partial sectional view of the substrate which begins to come into contact with a blade of the earthing mechanism.

FIG. 6 is an enlarged partial sectional view of the substrate which is finally conducted with the blade.

FIG. 7 is a pictorial representation of a plate-like spring having its layout height relative to the contact starting height of the blade against the substrate.

FIG. 8 is diagram pictorially showing a relation of the contact start position and the conducted position.

FIG. 9 is a graph showing plots of a drag or “slip” amount relative to offset values between the height of contact start position and the layout height of the plate spring.

FIG. 10 is a graph showing curves of initial speed versus particle flying angle of particles.

FIG. 11 is a graphical representation of contaminant particles attached onto the top surface of a substrate which is coupled to ground by use of the earthing mechanism embodying the invention.

FIG. 12 is a bar graph showing several measured numbers of residual particles on substrates that are grounded by the embodiment earthing mechanism and by prior known mechanism.

FIG. 13 is a diagram showing in a table format the on-substrate residual particle numbers of the graph of FIG. 12.

FIG. 14 a macrophotograph showing an observed blade trace as formed on the substrate that is grounded by the embodiment earthing mechanism.

FIG. 15 is a side view of a modified version of the earthing mechanism, which has a pin-like contact structure for contact with the surface of a substrate being processed.

FIG. 16 is a perspective view of optics in one typical variable-shaped electron beam lithography apparatus.

FIG. 17 is a top plan view of a substrate earthing mechanism used in the EB lithography apparatus.

FIG. 18 is a side view of main part of the earthing mechanism in the lithography apparatus.

FIG. 19 is a graphical representation of contaminant particles attached to the top surface of a substrate which is coupled to ground by use of the earthing mechanism shown in FIGS. 17-18.

FIG. 20 is a macrophotograph showing several observed blade traces formed on the substrate that is grounded by the earthing mechanism of FIGS. 17-18.

Claims

1. A mechanism for coupling a substrate to ground potential, comprising: a plate-like spring extending toward the substrate in a direction parallel to a surface of the substrate; anda contact portion coupled to a tip end of the plate-like spring for coming into contact with the substrate to thereby provide electrical conduction therebetween, whereinsaid plate-like spring and said contact portion are to laid out to cause a contact position at which said contact portion is in contact with the substrate and a layout position of said plate-like spring to be substantially the same in position as each other in a direction at right angles to the substrate surface in a state that said plate-like spring is out of its elastic deformation.

2. The mechanism according to claim 1, wherein an offset value in the direction at right angles to the substrate surface between the contact position at which said contact portion is in contact with the substrate and the layout position of said plate-like spring in the state that said plate-like spring is out of its elastic deformation is within plus/minus one millimeter (±1 mm).

3. The mechanism according to claim 1, wherein said contact portion is substantially centrally disposed in a width direction of said plate-like spring.

4. The mechanism according to claim 1, further comprising: a cover overlying said contact portion while having a gap space between the cover and the substrate surface in a direction extending toward at least a central portion of said substrate from the position whereat said contact portion is in contact with said substrate.

5. The mechanism according to claim 1, wherein said contact portion includes any one of a blade with a knife edge and a pin.

6. The mechanism according to claim 1, wherein said substrate has thereon a conductive film and a resist film on or above said conductive film, and wherein said contact portion cuts into the resist film for making electrical conduction with the conductive film.

7. A charged-particle beam writing apparatus comprising: a stage structure elevatably mounting thereon a substrate to be written with a pattern by using a charged particle beam;a contact portion arranged contactable with the substrate by elevation of the substrate to thereby make electrical conduction with said substrate; anda plate-like spring member extending toward said substrate in a direction parallel with a surface of said substrate for causing said contact portion to be connected thereto substantially at a tip end of the plate-like spring, whereinsaid contact portion and said plate-like spring member are laid out so that a contact position at which said contact portion comes into contact with said substrate and a layout position of said plate-like spring member are substantially the same as each other with respect to an elevating direction of the stage in a state that said plate-like spring member is out of elastic deformation.

8. The apparatus according to claim 7, wherein an offset value in the direction at right angles to the substrate surface between the contact position at which said contact portion is in contact with the substrate and the layout position of said plate-like spring in the state that said plate-like spring is out of its elastic deformation is within ±1 mm.

9. The apparatus according to claim 7, wherein said contact portion is substantially centrally disposed in a width direction of said plate-like spring member.

10. The apparatus according to claim 7, further comprising: a cover overlying said contact portion while having a gap space between the cover and the substrate surface in a direction extending toward at least a central portion of said substrate from the position whereat said contact portion is in contact with said substrate.

11. The apparatus according to claim 7, wherein said contact portion includes any one of a blade with a knife edge and a pin.

12. The apparatus according to claim 7, wherein said substrate has thereon a conductive film and a resist film above the conductive film, and wherein said contact portion cuts into said resist film for making electrical conduction with said conductive film.