EUV Mask Handling Standards

Transcription

1 EUV Mask Handling Standards Scott Hector*, SEMATECH Mask Strategy Program Manager November 2004 * On assignment from Freescale Semiconductor, Inc. Acknowledge: Thomas White

2 Outline Standard for mask frame Standard for restrictions on mask layout to enable handling Standard for mask fiducial marks 2

3 Status of Draft Protection Standards EUV mask enclosure domain Defines a domain volume around the mask form factor within which any enclosure element must fit Draft discussed with several stakeholders and feedback received Mask handling areas Drafted but not yet distributed Handling areas are 5 mm wide regions around the entire substrate edge on both sides, plus entirety of sidewalls. Allows for active end effectors or passive contact points Chuck contact area excluded 3

4 Elements of the draft frame domain standard Physical dimensions of frame domain and region that contact end effectors may occupy are defined. Materials used to construct frame are not specified, but they are agreed upon between user and supplier. Surface of frame must be free of burrs, scores, particles or other discontinuities. Separate standard for test method to be referenced Labels on frame must be engraved. Minimum of four contact points 4

5 Proposed frame area standard D E F Mask Frame domain Arbitrary end effector C LX,Y C B A L Z C L X,Y C B Proposed by SEMATECH A Dimension A B C D E F Value (mm) Same as P37 P mm P mm Same as P37 P mm P mm 5

6 Proposed frame area standard TOP VIEW A SIDE VIEW B E A RETICLE A C D ENCLOSURE A A Separation between reticle side and enclosure side B Maximum width (symmetric in x and y) of enclosure C Separation between reticle active face (down) and enclosure D maximum distance between top of reticle and top of enclosure E maximum height from bottom of enclosure to top of reticle Proposed by Intel 6

7 Requested changes to draft frame standard Physical domain values should be changed Clearance for end effector robot needs to be 2-3 mm, not 0.5mm (dimensions B and E) Height of frame should be 10 mm (instead of 5.5 mm) Minimum number of contact points should be three instead of four 7

8 Layout elements standardized in SEMI P Area for patterns printed on wafer Maximum printable field (4x) 104 by 132 mm (26 by 33 mm at wafer) CL Area reserved for alignment marks, ID marks, and handling (The position of these items are to be negotiated between user and supplier.) CL

9 Elements of the draft handling areas standard Standard applies to all areas on the mask necessary for handling, holding, or contacting the mask, with the exception of the chuck clamping area on the mask back side. Defines location of handling areas Mask handling area materials or surface finishes shall be selected to provide the lowest levels of particle generation and molecular contamination outgassing practicable for manufacturing. Electrical conductivity properties of the mask handling areas shall be agreed upon between the user and supplier. Testing of the mask handling area properties shall be agreed upon between the user and supplier. 9

10 Proposed handling area standard Area reserved for handling Mask 5 mm 5 mm Handling areas on all four sides Plan view of front and back sides of mask Proposed by SEMATECH 10

11 Handling areas survey 5 mm These are the mask sidewalls. A B C This central block is the EUV mask pattern side, with a 5 mm border of handling area in segments. Corner segments (A) are 5 mm x 5 mm; side center segments (B) are 6 mm x 5 mm; and side general segments (C) are 4 mm x 5 mm (there are 17 side general segments between the corner and the side center segments). Backside corner chamfer. D The mask backside edges. Note corners D are the same segment. D 11

12 Handling survey response from Leica Handling areas required for metrology tools in green 12

13 Handling survey response from ASML Reserved for Alignment Reserved for Handling 13

14 Elements of the draft fiducial mark standard This specification details the physical requirements for permanent reference fiducial marks on an EUVL mask substrate Mark must be readable on final mask (e. g. after being coated with films specified in SEMI P38) The minimum number of reference fiducial marks on the mask substrate is four, one proximal to each corner of the substrate. Additional fiducial marks may be placed on the mask by agreement between the user and supplier Dimensions and permissible variations of mark defined Method of creation of the reference fiducial marks on the mask substrate is not defined to allow for innovative methods. The mask substrate must be cleaned of debris, if any, prior to any film depositions during the mask blank operations. The reference fiducial mark must have a proximal locator feature, capable of being recognized by automated equipment. The design of the locator feature shall be agreed upon between the user and supplier. Testing of the reference fiducial marks shall be agreed upon between the user and supplier. 14

15 Proposed fiducial mark standard 19.8 ± 0.1 mm W Marks located near each corner of top surface of mask Corner of mask top surface 5.4 ± 0.1 mm L S W Fiducial mark will be placed in center region. Mark parameter L, Length (long axis) S, Length (short axis) W, Axis width Depth (minimum) Depth (maximum) Size 9 ± 1 µm 7 ± 1 µm 1 ± 0.5 µm 50 nm 100 nm 300 µm Example locator mark 15

16 Summary Standards for mask handling have been proposed, but they need to be refined based on input provided by stakeholders More input on layout areas reserved for handling is requested Input on draft standard concepts is requested Standard for mask fiducial marks has been proposed Input on design, dimensions and location of mark is requested 16