MARK, METHOD FOR FORMING SAME, AND EXPOSURE APPARATUS

• US 20150200165A1
• Filed: 01/06/2015
• Published: 07/16/2015
• Est. Priority Date: 07/10/2012
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: FUJIWARA, Tomoharu, MAGOME, Nobutaka, SHIBA, Yuji
• Granted Patent: US 9,941,217 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G03F 9/708 Mark formation
• CPC Class Codes: H01L 21/3086 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 2223/5442 comprising non digital, non alphanumeric information, e.g. symbols
• CPC Class Codes: H01L 2223/54426 for alignment
• CPC Class Codes: H01L 2223/5446 Located in scribe lines
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A mark forming method includes: a step of forming a resist mark including recessed portion based on an image of a mark exposed on a wafer; a step of coating the recessed portion, in an area of the wafer in which the resist mark has been formed, with a polymer layer containing a block copolymer; a step of performing annealing for the polymer layer so as to allow the polymer layer to form a self-assembled area; a step of performing etching so as to selectively remove a portion of the self-assembled area; and a step of forming a wafer mark in the wafer by using the self-assembled area from which the portion thereof has been removed. When forming a circuit pattern by using the directed self-assemble of the block copolymer, a mark can be also formed, in parallel with the formation of the circuit pattern.

Claims

1. A mark forming method comprising:

forming recessed portion on a mark formation area of a substrate;

coating the recessed portion with a polymer layer containing a block copolymer;

allowing the polymer layer in the recessed portion to form a self-assembled area;

selectively removing a portion of the self-assembled area; and

forming a positioning mark by using the self-assembled area from which the portion of the self-assembled area has been removed.

2. The mark forming method according to claim 1, wherein a mark including the recessed portion is formed on the mark formation area;

and

the mark includes a plurality of line-pattern areas which are arranged periodically in a first direction and each of which includes the recessed portion, and at least one space-pattern area which is arranged between the plurality of line-pattern areas and which includes the recessed portion,

wherein allowing the polymer layer in the recessed portion to form the self-assembled area is performed such that a periodic direction of the self-assembled area formed in the recessed portion of each line-pattern area is different from a periodic direction of the self-assembled area formed in the recessed portion of the space-pattern area.

3. The mark forming method according to claim 2, wherein the mark includes a plurality of first guide patterns, having projected and linear shape, which are arranged in the first direction at a first period in at least one of the plurality of line-pattern areas, and a plurality of second guide patterns, having projected and linear shape, which are arranged in a second direction, orthogonal to the first direction, at a second period in the space-pattern area;

coating the recessed portion with the polymer layer is coating a plurality of first recessed portions between the plurality of first guide patterns and a plurality of second recessed portions between the plurality of second guide patterns with the polymer layer; and

allowing the polymer layer to form the self-assembled area is allowing the polymer layer in the plurality of first recessed portions to form a self-assembled area having a periodicity in the first direction, and allowing the polymer layer in the plurality of second recessed portions to form a self-assembled area having a periodicity in the second direction.

4. The mark forming method according to claim 3, wherein edge portions in the first direction of the plurality of second guide patterns are connected to one first guide pattern, among the plurality of first guide patterns, located at an end portion of an arrangement of the first guide patterns.

5. The mark forming method according to claim 1, wherein a mark including the recessed portion is formed on the mark formation area;

the mark includes a plurality of first line-pattern areas which are arranged periodically in a first direction and each of which includes the recessed portion, and a plurality of second line-pattern areas which are arranged periodically in a second direction, orthogonal to the first direction, and each of which includes the recessed portion;

allowing the polymer layer to form the self-assembled area is performed such that a periodic direction of the self-assembled area formed in each recessed portion of the plurality of first line-pattern areas is different from a periodic direction of the self-assembled area formed in each recessed portion of the plurality of second line pattern areas.

6. The mark forming method according to claim 5, wherein the mark includes a plurality of first guide patterns, having projected and linear shape, which are arranged in the first direction at a first period in at least one of the plurality of first line-pattern areas, and a plurality of second guide patterns, having projected and linear shape, which are arranged in the second direction at a second period in at least one of the plurality of second line-pattern areas;

coating the recessed portion with the polymer layer is coating a plurality of first recessed portions between the plurality of first guide patterns and a plurality of second recessed portions between the plurality of second guide patterns with the polymer layer; and

allowing the polymer layer to form the self-assembled area is allowing the polymer layer in the plurality of first recessed portions to form a self-assembled area having a periodicity in the first direction, and allowing the polymer layer in the plurality of second recessed portions to form a self-assembled area having a periodicity in the second direction.

7. The mark forming method according to claim 6, wherein the mark is formed by exposing an image of the mark in the mark formation area;

in a case that the mark is formed, a resolution in the second direction is set to be lower than a resolution in the first direction; and

the second period of the plurality of second guide patterns is set to be greater than the first period of the plurality of first guide patterns.

8. The mark forming method according to claim 1, wherein a mark including the recessed portion is formed on the mark formation area;

the mark includes a line pattern area including the recessed portion and an adjacent area adjacent to the line-pattern area and including the recessed portion;

selectively removing the portion of the self-assembled area is performed such that density of recessed portions allowed to remain in the self-assembled area formed in the line-pattern area is different from density of recessed portions allowed to remain in the self-assembled area formed in the adjacent area.

9. The mark forming method according to claim 1, wherein the substrate has a first mark-formation layer in which a circuit pattern of which period is minutest in a first direction is formed, and a second mark-formation layer in which a circuit pattern of which period is minutest in a second direction orthogonal to the first direction is formed;

marks periodically arranged in the first direction are formed in the first mark-formation layer of the substrate, via a first mask layer obtained by removing the portion of the self-assembled area periodically formed in the first direction in the polymer layer; and

marks periodically arranged in the second direction are formed in the second mark-formation layer of the substrate, via a second mask layer obtained by removing the portion of the self-assembled area periodically formed in the second direction in the polymer layer.

14. A method for producing a device comprising:

forming, in a substrate, an alignment mark for alignment between layers of the substrate by using the mark forming method as defined in claim 1;

performing the alignment by using the alignment mark and performing exposure for the substrate; and

processing the exposed substrate.

10. A mark for positioning which is formed in a mark formation area of a substrate, the mark comprising:

a plurality of line-pattern areas formed periodically in a first direction; and

at least one space-pattern area between the plurality of line-pattern areas,

wherein a first structure which is optically unresolvable is formed in the line-pattern areas,

a second structure which is optically unresolvable is formed in the space-pattern area, and

a periodic direction of the first structure is different from a periodic direction of the second structure.

11. The mark according to claim 10, wherein the first structure is periodically formed, in the first direction, between a plurality of linear patterns which are periodically formed in the first direction in each of the plurality of line pattern areas;

and

the at least one space pattern is provided as a plurality of space-pattern areas, and the second structure is periodically formed, in the second direction, between a plurality of linear patterns which are periodically formed in the second direction orthogonal to the first direction in each of the plurality of space-pattern areas.

12. The mark according to claim 10, wherein the mark includes a plurality of first line-pattern areas which are arranged periodically in the first direction, and a plurality of second line-pattern areas which are arranged periodically in a second direction orthogonal to the first direction;

a first structure which is optically unresolvable is formed periodically in the first direction in each of the plurality of first line-pattern areas, and a second structure which is optically unresolvable is formed periodically in the second direction in each of the plurality of second line-pattern areas, and

period of the first structure is different from period of the second structure.

13. An exposure apparatus which illuminates a pattern with an exposure light and exposes a substrate with the exposure light via the pattern and a projection optical system, the exposure apparatus comprising:

a mark illumination system configured to illuminate a mark, formed in the substrate, with an illumination light of which polarization state is controllable;

a detecting section configured to receive a light from the mark and detect the mark; and

a control system configured to control, in a case that a structure unresolvable by the illumination light is included in the mark, the polarization state of the illumination light depending on a periodic direction of the structure.

15. A method for producing a device comprising:

exposing a photosensitive substrate by using the exposure apparatus as defined in claim 13; and

processing the exposed photosensitive substrate.