US20120237857A1 - Photomask and method for forming overlay mark using the same - Google Patents
Photomask and method for forming overlay mark using the same Download PDFInfo
- Publication number
- US20120237857A1 US20120237857A1 US13/049,047 US201113049047A US2012237857A1 US 20120237857 A1 US20120237857 A1 US 20120237857A1 US 201113049047 A US201113049047 A US 201113049047A US 2012237857 A1 US2012237857 A1 US 2012237857A1
- Authority
- US
- United States
- Prior art keywords
- areas
- photomask
- patterns
- mark
- photoresist layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/38—Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
- G03F1/42—Alignment or registration features, e.g. alignment marks on the mask substrates
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/70605—Workpiece metrology
- G03F7/70616—Monitoring the printed patterns
- G03F7/70633—Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
Definitions
- the present invention generally relates to a photomask and an overlay mark, and more particularly, to a photomask having ring areas and a method for forming an overlay mark in a substrate using the same during double patterning.
- the IC manufacturing process involves more than two photomasks of different patterns to perform a double patterning. Therefore, the alignment between the photomasks determines the quality of patterns transferred to the target layer and the final performance of the IC.
- FIG. 1A shows a top view of a pattern of a conventional photomask.
- the pattern 1 has a first rectangular region 11 , a second rectangular region 12 , a third rectangular region 13 and a fourth rectangular region 14 .
- the longer side of the first rectangular region 11 and the longer side of the third rectangular region 13 are parallel to each other, while the longer side of the second rectangular region 12 and the longer side of the fourth rectangular region 14 are parallel to each other.
- the longer side of the first rectangular region 11 or the third rectangular region 13 is perpendicular to the longer side of the second rectangular region 12 or the fourth rectangular region 14 . Therefore, along the horizontal and vertical directions, there are two parallel and symmetrical rectangular regions.
- FIG. 1B shows a top view of an overlay mark in a substrate.
- the overlay mark 2 is formed on the substrate after the previous process is completed.
- the overlay mark 2 includes a first aligned rectangular region 21 , a second aligned rectangular region 22 , a third aligned rectangular region 23 and a fourth aligned rectangular region 24 .
- FIG. 1C shows a top view of an alignment configuration.
- the pattern 1 in FIG. 1A is transferred on a photoresist layer on the substrate to form a mark pattern 1 a .
- the mark pattern 1 a has a first rectangular region 11 a , a second rectangular region 12 a , a third rectangular region 13 a and a fourth rectangular region 14 a .
- a metrology process is performed to determine the alignment precision by referring to the overlay mark 2 and the mark pattern 1 a on the photoresist layer.
- the alignment step is performed. If the measured gap meets the predetermined criterion, the patternization is successful and process continues. However, if the criterion is not met, the failed photoresist layer at this stage must be removed and the lithography process is repeated again until the criterion is met.
- FIGS. 2A to 2G show a conventional method for forming an overlay mark in a substrate.
- the overlay mark 2 is constituted by a plurality of hollow cylinders 36 ( FIG. 2G ), which are formed as described below.
- a photoresist layer 31 is applied on a substrate 30 .
- a photomask 32 is provided.
- the photomask 32 comprises a plurality of patterns, and the patterns comprise a plurality of square areas 33 .
- Each of the square areas 33 has the same light transmittancy, and the light transmittancy of the square areas 33 is different from that of the other area of the photomask 32 .
- the square areas 33 are light transmissive, and the other area of the photomask 32 is opaque.
- FIGS. 2C and 2D wherein FIG. 2C is a top view of FIG. 2D , an exposure and development process is performed so that the photoresist layer 31 has a plurality of mark patterns.
- the mark pattern comprises a plurality of holes 34 .
- FIG. 2E a plurality of spacers 35 are formed on the sidewalls of the holes 34 .
- the photoresist layer 31 is removed, and the spacers 35 remain on the substrate 30 .
- the substrate 30 is etched to form an overlay mark 2 corresponding to the spacers 35 .
- the overlay mark 2 includes a plurality of hollow cylinders 36 .
- the material of the spacers 35 is metal oxide, therefore, in the etching process, the spacers 35 can serve as a mask.
- FIG. 2H shows a cross-sectional view of a conventional overlaying structure on the substrate of FIG. 2G .
- a priming step is performed to apply an adhesive layer 37 on the substrate 30 .
- a second photoresist layer 38 is applied on the adhesive layer 37 to adhere to the substrate 30 .
- an exposure and development process is performed, so that the second photoresist layer 38 has a plurality of second mark patterns 39 which are the same as the mark pattern 1 a in FIG. 1C .
- the second mark patterns 39 are located over the overlay mark 2 . Therefore, a metrology process is performed to determine the alignment precision by referring to the second mark patterns 39 and the overlay mark 2 . As shown in FIG. 2H , the measured distance d 1 provided by the second mark patterns 39 and the overlay mark 2 can be used to perform the alignment procedure.
- the drawback of the overlaying structure of FIG. 2H is as follows.
- the spacers 35 and the hollow cylinders 36 have the same thickness T 1 , which is very thin. Therefore, when the metrology process is performed, the contrast is low, and it is very difficult to find the overlay mark 2 .
- the present invention is directed to a photomask, which comprises a plurality of patterns. At least one of the patterns comprises a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas.
- the present invention is also directed to a method for forming an overlay mark in a substrate, comprising the steps of: applying a photoresist layer on a substrate; providing a photomask, the photomask comprising a plurality of patterns, at least one of the patterns comprising a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas; performing an exposure and development process, so that the photoresist layer has a plurality of mark patterns, at least one of the mark patterns comprises a plurality of holes and a plurality of pillars within the holes, and a gap is between the sidewall of each hole and the sidewall of the pillar; forming a plurality of spacers on the sidewalls of the holes and the sidewalls of the pillars, wherein the bottoms of the spacers in the gaps join together to form a plurality of thick spacers; removing the photoresist layer, wherein the thick space
- the present invention is also directed to a method for insuring an alignment precision in a double patterning process, comprising the steps of: applying a first photoresist layer on a substrate; providing a photomask, the photomask comprising a plurality of patterns, at least one of the patterns comprising a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas; performing an exposure and development process, so that the first photoresist layer has a plurality of first mark patterns, at least one of the first mark patterns comprises a plurality of holes and a plurality of pillars within the holes, and a gap is between the sidewall of each hole and the sidewall of the pillar; forming a plurality of spacers on the sidewalls of the holes and the sidewalls of the pillars, wherein the bottoms of the spacers in the gaps join together to form a plurality of thick spacers; removing the first photore
- the thickness of the overlay mark is large, the contrast is high when the metrology process is performed, and it is easy to find the overlay mark.
- FIG. 1A is a top view of a pattern of a conventional photomask
- FIG. 1B is a top view of an overlay mark in a substrate
- FIG. 1C is a top view of an alignment configuration
- FIGS. 2A to 2G show a conventional method for forming an overlay mark in a substrate
- FIG. 2H is a cross-sectional view of a conventional overlaying structure on the substrate of FIG. 2G ;
- FIGS. 3A to 3G show a method for forming an overlay mark in a substrate according to an embodiment of the present invention
- FIG. 3H is a cross-sectional view of an overlaying structure on the substrate of FIG. 3G ;
- FIG. 4 is a top view of an alignment configuration according to an embodiment of the present invention.
- FIGS. 3A to 3G show a method for forming an overlay mark in a substrate according to an embodiment of the present invention.
- the overlay mark 6 comprises a plurality of hollow cylinders 46 ( FIG. 3G ), which are formed as described below.
- a first photoresist layer 41 is applied on a substrate 40 (for example, a wafer).
- a photomask 42 is provided.
- the photomask 42 comprises a first rectangular region, a second rectangular region adjacent to the first rectangular region, a third rectangular region diagonal relative to the first rectangular region and adjacent to the second rectangular region, and a fourth rectangular region diagonal relative to the second rectangular region and adjacent to both the first rectangular region and the third rectangular region.
- the first rectangular region is parallel to the third rectangular region, while the second rectangular region is perpendicular to the first rectangular region and parallel to the fourth rectangular region.
- the photomask 42 comprises a plurality of patterns that include a first pattern in the first rectangular region, a second pattern in the second rectangular region, a third pattern in the third rectangular region and a fourth pattern in the fourth rectangular region. At least one of the first pattern, the second pattern, the third pattern and the fourth pattern comprises a plurality of ring areas 43 and a plurality of inner areas 431 enclosed by the ring areas 43 .
- the light transmittancy of the ring areas 43 is different from that of the inner areas 431 .
- the light transmittancy of the inner areas 431 is same as that of the other area of the photomask 42 .
- the ring areas 43 are light transmissive, and the inner areas 431 and the other area of the photomask 42 are opaque.
- the periphery of the ring area 43 is square, and the inner area 431 is also square.
- At least one of the other patterns may is comprise a plurality of parallel strip areas, wherein each of the strip areas has the same light transmittancy.
- FIG. 3C is a top view of FIG. 3D
- an exposure and development process is performed so that the first photoresist layer 41 has a plurality of first mark patterns.
- the first mark pattern comprises a plurality of holes 44 and a plurality of pillars 441 within the holes 44 , and a gap 442 is between the sidewall of each hole 44 and the sidewall of the pillar 441 .
- the width of the gap 442 is defined as G, where
- T 1 is the thickness of the spacers 35 and the hollow cylinders 36 ( FIG. 2H ).
- the patterns of the photomask 42 comprise a plurality of parallel strip areas
- the first mark patterns of the first photoresist layer 41 comprise a plurality of trenches.
- a plurality of spacers are formed on the sidewalls of the holes 44 and the sidewalls of the pillars 441 .
- the bottoms of the spacers in the gaps 441 join together to form a plurality of thick spacers 45 , and each of the thick spacers 45 has a notch at the top thereof.
- the thickness of the bottom of the thick spacer 45 is equal to the width G of the gap 442 .
- the thick spacer 45 may fill the gap 442 , and the thick spacer 45 has a uniform thickness which is equal to the width G of the gap 442 .
- the first photoresist layer 41 is removed, and the thick spacers 45 remain on the substrate 40 .
- the substrate 40 is etched to form an overlay mark 6 corresponding to the thick spacers 45 .
- the overlay mark 6 includes a plurality of hollow cylinders 46 .
- the material of the thick spacers 45 is metal oxide, therefore, in the etching process, the thick spacers 45 can serve as a mask.
- FIG. 3H shows a cross-sectional view of an overlaying structure on the substrate of FIG. 3G .
- a priming step is performed to apply an adhesive layer 47 on the substrate 40 .
- the material of the adhesive layer 47 is Hexamethyldisilazane (HMDS).
- HMDS Hexamethyldisilazane
- a second photoresist layer 48 is applied on the adhesive layer 47 to adhere to the substrate 40 .
- an exposure and development process is performed, so that the second photoresist layer 48 has a plurality of second mark patterns 49 .
- the second mark patterns 49 are located over the overlay mark 6 . Therefore, a metrology process is performed to determine the alignment precision by referring to the second mark patterns 49 and the overlay mark 6 . As shown in FIG. 3H , the measured distance d 2 provided by the second mark patterns 49 and the overlay mark 6 can be used to perform the alignment procedure.
- FIG. 4 shows a top view of an alignment configuration according to an embodiment of the present invention.
- the overlay mark 6 includes a first aligned rectangular region 61 , a second aligned rectangular region 62 , a third aligned rectangular region 63 and a fourth aligned rectangular region 64 . Since the overlay mark 6 is formed according to the photomask 42 , the overlay mark 6 corresponds to the patterns of the photomask 42 .
- the mark pattern 5 a of the second photoresist layer 48 has a first rectangular region 51 a , a second rectangular region 52 a , a third rectangular region 53 a and a fourth rectangular region 54 a .
- the mark pattern 5 a is the same as the second mark patterns 49 in FIG. 3H .
- the second mark patterns 49 comprise a plurality of trenches.
- the second mark patterns 49 of the second photoresist layer may comprise a plurality of holes 34 and spacers 35 ( FIG. 2E ) or a plurality of holes 44 , pillars 441 and thick spacers 45 ( FIG. 3E ).
- the alignment step is performed. If the measured distance d 2 meets the predetermined criterion, the patternization is successful and the process continues. However, if the criterion is not met, the failed photoresist layer at this stage must be removed and the lithography process is repeated again until the criterion is met.
- the thickness T 2 of the hollow cylinders 46 is the same as the width G of the gap 442 , therefore,
- the thickness of the hollow cylinders 46 is large, the contrast is high when the metrology process is performed, and it is easy to find the overlay mark 6 .
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Preparing Plates And Mask In Photomechanical Process (AREA)
Abstract
The present invention relates to a photomask and a method for forming an overlay mark in a substrate using the same. The photomask comprises a plurality of patterns. At least one of the patterns comprises a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas. When the photomask is applied in a photolithography process, the formed overlay mark has a large thickness. Therefore, the contrast is high when a metrology process is performed, and it is easy to find the overlay mark.
Description
- The present invention generally relates to a photomask and an overlay mark, and more particularly, to a photomask having ring areas and a method for forming an overlay mark in a substrate using the same during double patterning.
- Currently, the IC manufacturing process involves more than two photomasks of different patterns to perform a double patterning. Therefore, the alignment between the photomasks determines the quality of patterns transferred to the target layer and the final performance of the IC.
-
FIG. 1A shows a top view of a pattern of a conventional photomask. Thepattern 1 has a firstrectangular region 11, a secondrectangular region 12, a thirdrectangular region 13 and a fourthrectangular region 14. The longer side of the firstrectangular region 11 and the longer side of the thirdrectangular region 13 are parallel to each other, while the longer side of the secondrectangular region 12 and the longer side of the fourthrectangular region 14 are parallel to each other. The longer side of the firstrectangular region 11 or the thirdrectangular region 13 is perpendicular to the longer side of the secondrectangular region 12 or the fourthrectangular region 14. Therefore, along the horizontal and vertical directions, there are two parallel and symmetrical rectangular regions. -
FIG. 1B shows a top view of an overlay mark in a substrate. Theoverlay mark 2 is formed on the substrate after the previous process is completed. Theoverlay mark 2 includes a first alignedrectangular region 21, a second alignedrectangular region 22, a third alignedrectangular region 23 and a fourth alignedrectangular region 24. -
FIG. 1C shows a top view of an alignment configuration. Thepattern 1 inFIG. 1A is transferred on a photoresist layer on the substrate to form a mark pattern 1 a. The mark pattern 1 a has a firstrectangular region 11 a, a secondrectangular region 12 a, a thirdrectangular region 13 a and a fourthrectangular region 14 a. A metrology process is performed to determine the alignment precision by referring to theoverlay mark 2 and the mark pattern 1 a on the photoresist layer. Specifically, by measuring the gap between the first alignedrectangular region 21, the second alignedrectangular region 22, the third alignedrectangular region 23 and the fourth alignedrectangular region 24 and the firstrectangular region 11 a, the secondrectangular region 12 a, the thirdrectangular region 13 a and the fourthrectangular region 14 a, the alignment step is performed. If the measured gap meets the predetermined criterion, the patternization is successful and process continues. However, if the criterion is not met, the failed photoresist layer at this stage must be removed and the lithography process is repeated again until the criterion is met. -
FIGS. 2A to 2G show a conventional method for forming an overlay mark in a substrate. In another prior art, theoverlay mark 2 is constituted by a plurality of hollow cylinders 36 (FIG. 2G ), which are formed as described below. Referring toFIG. 2A , aphotoresist layer 31 is applied on asubstrate 30. Referring toFIG. 2B , aphotomask 32 is provided. Thephotomask 32 comprises a plurality of patterns, and the patterns comprise a plurality ofsquare areas 33. Each of thesquare areas 33 has the same light transmittancy, and the light transmittancy of thesquare areas 33 is different from that of the other area of thephotomask 32. Usually, thesquare areas 33 are light transmissive, and the other area of thephotomask 32 is opaque. - Referring to
FIGS. 2C and 2D , whereinFIG. 2C is a top view ofFIG. 2D , an exposure and development process is performed so that thephotoresist layer 31 has a plurality of mark patterns. The mark pattern comprises a plurality ofholes 34. Referring toFIG. 2E , a plurality ofspacers 35 are formed on the sidewalls of theholes 34. - Referring to
FIG. 2F , thephotoresist layer 31 is removed, and thespacers 35 remain on thesubstrate 30. Referring toFIG. 2G , thesubstrate 30 is etched to form anoverlay mark 2 corresponding to thespacers 35. Theoverlay mark 2 includes a plurality ofhollow cylinders 36. The material of thespacers 35 is metal oxide, therefore, in the etching process, thespacers 35 can serve as a mask. -
FIG. 2H shows a cross-sectional view of a conventional overlaying structure on the substrate ofFIG. 2G . A priming step is performed to apply anadhesive layer 37 on thesubstrate 30. Next, a secondphotoresist layer 38 is applied on theadhesive layer 37 to adhere to thesubstrate 30. Then, an exposure and development process is performed, so that the secondphotoresist layer 38 has a plurality ofsecond mark patterns 39 which are the same as the mark pattern 1 a inFIG. 1C . - The
second mark patterns 39 are located over theoverlay mark 2. Therefore, a metrology process is performed to determine the alignment precision by referring to thesecond mark patterns 39 and theoverlay mark 2. As shown inFIG. 2H , the measured distance d1 provided by thesecond mark patterns 39 and theoverlay mark 2 can be used to perform the alignment procedure. - The drawback of the overlaying structure of
FIG. 2H is as follows. Thespacers 35 and thehollow cylinders 36 have the same thickness T1, which is very thin. Therefore, when the metrology process is performed, the contrast is low, and it is very difficult to find theoverlay mark 2. - The present invention is directed to a photomask, which comprises a plurality of patterns. At least one of the patterns comprises a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas.
- The present invention is also directed to a method for forming an overlay mark in a substrate, comprising the steps of: applying a photoresist layer on a substrate; providing a photomask, the photomask comprising a plurality of patterns, at least one of the patterns comprising a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas; performing an exposure and development process, so that the photoresist layer has a plurality of mark patterns, at least one of the mark patterns comprises a plurality of holes and a plurality of pillars within the holes, and a gap is between the sidewall of each hole and the sidewall of the pillar; forming a plurality of spacers on the sidewalls of the holes and the sidewalls of the pillars, wherein the bottoms of the spacers in the gaps join together to form a plurality of thick spacers; removing the photoresist layer, wherein the thick spacers remain; and etching the substrate to form an overlay mark corresponding to the thick spacers.
- The present invention is also directed to a method for insuring an alignment precision in a double patterning process, comprising the steps of: applying a first photoresist layer on a substrate; providing a photomask, the photomask comprising a plurality of patterns, at least one of the patterns comprising a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas; performing an exposure and development process, so that the first photoresist layer has a plurality of first mark patterns, at least one of the first mark patterns comprises a plurality of holes and a plurality of pillars within the holes, and a gap is between the sidewall of each hole and the sidewall of the pillar; forming a plurality of spacers on the sidewalls of the holes and the sidewalls of the pillars, wherein the bottoms of the spacers in the gaps join together to form a plurality of thick spacers; removing the first photoresist layer, wherein the thick spacers remain; etching the substrate to form an overlay mark corresponding to the thick spacers; applying a second photoresist layer on the substrate; performing an exposure and development process, so that the second photoresist layer has a plurality of second mark patterns, wherein the second mark patterns are located over the overlay mark; and performing a metrology process to determine the alignment precision by referring to the second mark patterns and the overlay mark.
- In the present invention, the thickness of the overlay mark is large, the contrast is high when the metrology process is performed, and it is easy to find the overlay mark.
- The foregoing has outlined rather broadly the features of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features of the invention will be described hereinafter, and form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
- The objectives of the present invention will become apparent upon reading the following description and upon reference to the accompanying drawings in which:
-
FIG. 1A is a top view of a pattern of a conventional photomask; -
FIG. 1B is a top view of an overlay mark in a substrate; -
FIG. 1C is a top view of an alignment configuration; -
FIGS. 2A to 2G show a conventional method for forming an overlay mark in a substrate; -
FIG. 2H is a cross-sectional view of a conventional overlaying structure on the substrate ofFIG. 2G ; -
FIGS. 3A to 3G show a method for forming an overlay mark in a substrate according to an embodiment of the present invention; -
FIG. 3H is a cross-sectional view of an overlaying structure on the substrate ofFIG. 3G ; and -
FIG. 4 is a top view of an alignment configuration according to an embodiment of the present invention. -
FIGS. 3A to 3G show a method for forming an overlay mark in a substrate according to an embodiment of the present invention. In the present invention, theoverlay mark 6 comprises a plurality of hollow cylinders 46 (FIG. 3G ), which are formed as described below. Referring toFIG. 3A , afirst photoresist layer 41 is applied on a substrate 40 (for example, a wafer). Referring toFIG. 3B , aphotomask 42 is provided. Thephotomask 42 comprises a first rectangular region, a second rectangular region adjacent to the first rectangular region, a third rectangular region diagonal relative to the first rectangular region and adjacent to the second rectangular region, and a fourth rectangular region diagonal relative to the second rectangular region and adjacent to both the first rectangular region and the third rectangular region. The first rectangular region is parallel to the third rectangular region, while the second rectangular region is perpendicular to the first rectangular region and parallel to the fourth rectangular region. - The
photomask 42 comprises a plurality of patterns that include a first pattern in the first rectangular region, a second pattern in the second rectangular region, a third pattern in the third rectangular region and a fourth pattern in the fourth rectangular region. At least one of the first pattern, the second pattern, the third pattern and the fourth pattern comprises a plurality ofring areas 43 and a plurality ofinner areas 431 enclosed by thering areas 43. The light transmittancy of thering areas 43 is different from that of theinner areas 431. Preferably, the light transmittancy of theinner areas 431 is same as that of the other area of thephotomask 42. In this embodiment, thering areas 43 are light transmissive, and theinner areas 431 and the other area of thephotomask 42 are opaque. The periphery of thering area 43 is square, and theinner area 431 is also square. - In another embodiment, at least one of the other patterns may is comprise a plurality of parallel strip areas, wherein each of the strip areas has the same light transmittancy.
- Referring to
FIGS. 3C and 3D , whereinFIG. 3C is a top view ofFIG. 3D , an exposure and development process is performed so that thefirst photoresist layer 41 has a plurality of first mark patterns. The first mark pattern comprises a plurality ofholes 44 and a plurality ofpillars 441 within theholes 44, and agap 442 is between the sidewall of eachhole 44 and the sidewall of thepillar 441. The width of thegap 442 is defined as G, where - T1<G<2T1, wherein T1 is the thickness of the
spacers 35 and the hollow cylinders 36 (FIG. 2H ). - It should be understood that if the patterns of the
photomask 42 comprise a plurality of parallel strip areas, the first mark patterns of thefirst photoresist layer 41 comprise a plurality of trenches. - Referring to
FIG. 3E , a plurality of spacers are formed on the sidewalls of theholes 44 and the sidewalls of thepillars 441. In this embodiment, the bottoms of the spacers in thegaps 441 join together to form a plurality ofthick spacers 45, and each of thethick spacers 45 has a notch at the top thereof. The thickness of the bottom of thethick spacer 45 is equal to the width G of thegap 442. Alternatively, thethick spacer 45 may fill thegap 442, and thethick spacer 45 has a uniform thickness which is equal to the width G of thegap 442. - Referring to
FIG. 3F , thefirst photoresist layer 41 is removed, and thethick spacers 45 remain on thesubstrate 40. Referring toFIG. 3G , thesubstrate 40 is etched to form anoverlay mark 6 corresponding to thethick spacers 45. Theoverlay mark 6 includes a plurality ofhollow cylinders 46. The material of thethick spacers 45 is metal oxide, therefore, in the etching process, thethick spacers 45 can serve as a mask. -
FIG. 3H shows a cross-sectional view of an overlaying structure on the substrate ofFIG. 3G . When a method for insuring an alignment precision in a double patterning process on thesubstrate 40 is performed, the following steps need to be further performed. A priming step is performed to apply anadhesive layer 47 on thesubstrate 40. In this embodiment, the material of theadhesive layer 47 is Hexamethyldisilazane (HMDS). Next, asecond photoresist layer 48 is applied on theadhesive layer 47 to adhere to thesubstrate 40. Then, an exposure and development process is performed, so that thesecond photoresist layer 48 has a plurality ofsecond mark patterns 49. - The
second mark patterns 49 are located over theoverlay mark 6. Therefore, a metrology process is performed to determine the alignment precision by referring to thesecond mark patterns 49 and theoverlay mark 6. As shown inFIG. 3H , the measured distance d2 provided by thesecond mark patterns 49 and theoverlay mark 6 can be used to perform the alignment procedure. -
FIG. 4 shows a top view of an alignment configuration according to an embodiment of the present invention. In this embodiment, theoverlay mark 6 includes a first alignedrectangular region 61, a second alignedrectangular region 62, a third alignedrectangular region 63 and a fourth alignedrectangular region 64. Since theoverlay mark 6 is formed according to thephotomask 42, theoverlay mark 6 corresponds to the patterns of thephotomask 42. - The
mark pattern 5 a of thesecond photoresist layer 48 has a firstrectangular region 51 a, a secondrectangular region 52 a, a thirdrectangular region 53 a and a fourthrectangular region 54 a. Themark pattern 5 a is the same as thesecond mark patterns 49 inFIG. 3H . In this embodiment, thesecond mark patterns 49 comprise a plurality of trenches. However, it should be understood that thesecond mark patterns 49 of the second photoresist layer may comprise a plurality ofholes 34 and spacers 35 (FIG. 2E ) or a plurality ofholes 44,pillars 441 and thick spacers 45 (FIG. 3E ). - By measuring the distance d2 between the first aligned
rectangular region 61, the second alignedrectangular region 62, the third alignedrectangular region 63 and the fourth alignedrectangular region 64 and the firstrectangular region 51 a, the secondrectangular region 52 a, the thirdrectangular region 53 a and the fourthrectangular region 54 a, the alignment step is performed. If the measured distance d2 meets the predetermined criterion, the patternization is successful and the process continues. However, if the criterion is not met, the failed photoresist layer at this stage must be removed and the lithography process is repeated again until the criterion is met. - In the present invention, as shown in
FIG. 3H , the thickness T2 of thehollow cylinders 46 is the same as the width G of thegap 442, therefore, -
T1<T2<2T1. - Since the thickness of the
hollow cylinders 46 is large, the contrast is high when the metrology process is performed, and it is easy to find theoverlay mark 6. - Although the present invention and its objectives have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. For example, many of the processes discussed above can be implemented in different methodologies and replaced by other processes, or a combination thereof.
- Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, to manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Claims (16)
1. A photomask, comprising a plurality of patterns, at least one of the patterns comprising a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas.
2. The photomask of claim 1 , wherein the periphery of the ring area is square, and the inner area is also square.
3. The photomask of claim 1 , wherein the inner areas are opaque, and the ring areas are light transmissive.
4. The photomask of claim 1 , wherein at least one of the other patterns comprises a plurality of strip areas, and each of the strip areas has the same light transmittancy.
5. A method for forming an overlay mark in a substrate, comprising:
applying a photoresist layer on a substrate;
providing a photomask, the photomask comprising a plurality of patterns, at least one of the patterns comprising a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas;
performing an exposure and development process, so that the photoresist layer has a plurality of mark patterns, at least one of the mark patterns comprises a plurality of holes and a plurality of pillars within the holes, and a gap is between the sidewall of each hole and the sidewall of the pillar;
forming a plurality of spacers on the sidewalls of the holes and the sidewalls of the pillars, wherein the bottoms of the spacers in the gaps join together to form a plurality of thick spacers;
removing the photoresist layer, wherein the thick spacers remain; and
etching the substrate to form an overlay mark corresponding to the thick spacers.
6. The method of claim 5 , wherein the periphery of the ring area of the photomask is square, and the inner area of the photomask is also square.
7. The method of claim 5 , wherein the inner areas of the photomask are opaque, and the ring areas of the photomask are light transmissive.
8. The method of claim 5 , wherein at least one of other patterns to of the photomask comprises a plurality of strip areas, and each of the strip areas has the same light transmittancy.
9. The method of claim 5 , wherein at least one of the other mark patterns of the photoresist layer comprises a plurality of trenches.
10. A method for insuring an alignment precision in a double patterning process, comprising:
applying a first photoresist layer on a substrate;
providing a photomask, the photomask comprising a plurality of patterns, at least one of the patterns comprising a plurality of ring areas and a plurality of inner areas enclosed by the ring areas, wherein the light transmittancy of the ring areas is different from that of the inner areas;
performing an exposure and development process, so that the first photoresist layer has a plurality of first mark patterns, at least one of the first mark patterns comprises a plurality of holes and a plurality of pillars within the holes, and a gap is between the sidewall of each hole and the sidewall of the pillar;
forming a plurality of spacers on the sidewalls of the holes and the sidewalls of the pillars, wherein the bottoms of the spacers in the gaps join together to form a plurality of thick spacers;
removing the first photoresist layer, wherein the thick spacers remain;
etching the substrate to form an overlay mark corresponding to the thick spacers;
applying a second photoresist layer on the substrate;
performing an exposure and development process, so that the second photoresist layer has a plurality of second mark patterns, wherein the second mark patterns are located over the overlay mark; and
performing a metrology process to determine the alignment precision by referring to the second mark patterns and the overlay mark.
11. The method of claim 10 , wherein the periphery of the ring area of the photomask is square, and the inner area of the photomask is also square.
12. The method of claim 10 , wherein the inner areas of the photomask are opaque, and the ring areas of the photomask are light transmissive.
13. The method of claim 10 , wherein at least one of the other patterns of the photomask comprises a plurality of strip areas, and each of the strip areas has the same light transmittancy.
14. The method of claim 10 , wherein at least one of the other first mark patterns of the first photoresist layer comprises a plurality of trenches.
15. The method of claim 10 , wherein the second mark patterns of the second photoresist layer comprise a plurality of holes.
16. The method of claim 10 , wherein the second mark patterns of the second photoresist layer comprise a plurality of trenches.
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/049,047 US20120237857A1 (en) | 2011-03-16 | 2011-03-16 | Photomask and method for forming overlay mark using the same |
TW100114821A TWI434135B (en) | 2011-03-16 | 2011-04-28 | Photomask and method for forming overlay mark using the same |
CN201110164983.9A CN102681330B (en) | 2011-03-16 | 2011-06-20 | Photomask and method for forming overlay mark using same and precision improvement method for counterpoint of secondary pattern technology |
US13/776,122 US8535858B2 (en) | 2011-03-16 | 2013-02-25 | Photomask and method for forming overlay mark using the same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/049,047 US20120237857A1 (en) | 2011-03-16 | 2011-03-16 | Photomask and method for forming overlay mark using the same |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/776,122 Division US8535858B2 (en) | 2011-03-16 | 2013-02-25 | Photomask and method for forming overlay mark using the same |
Publications (1)
Publication Number | Publication Date |
---|---|
US20120237857A1 true US20120237857A1 (en) | 2012-09-20 |
Family
ID=46813458
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/049,047 Abandoned US20120237857A1 (en) | 2011-03-16 | 2011-03-16 | Photomask and method for forming overlay mark using the same |
US13/776,122 Active US8535858B2 (en) | 2011-03-16 | 2013-02-25 | Photomask and method for forming overlay mark using the same |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/776,122 Active US8535858B2 (en) | 2011-03-16 | 2013-02-25 | Photomask and method for forming overlay mark using the same |
Country Status (3)
Country | Link |
---|---|
US (2) | US20120237857A1 (en) |
CN (1) | CN102681330B (en) |
TW (1) | TWI434135B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160322307A1 (en) * | 2015-04-28 | 2016-11-03 | Kabushiki Kaisha Toshiba | Method of forming mark pattern, recording medium and method of generating mark data |
US20180188646A1 (en) * | 2015-09-24 | 2018-07-05 | Korea Research Institute Of Standards And Science | Method for manufacturing transparent substrate and method for manufacturing surface enhanced raman scattering substrate using the same |
US10249570B2 (en) * | 2012-06-28 | 2019-04-02 | Taiwan Semiconductor Manufacturing Company, Ltd. | Overlay mark |
CN109870876A (en) * | 2017-12-05 | 2019-06-11 | 长鑫存储技术有限公司 | A kind of alignment pattern production method |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8745546B2 (en) * | 2011-12-29 | 2014-06-03 | Nanya Technology Corporation | Mask overlay method, mask, and semiconductor device using the same |
CN105182697B (en) * | 2015-08-28 | 2017-05-10 | 京东方科技集团股份有限公司 | On Cell structure touch display screen and manufacturing method thereof and display device |
CN110109325A (en) * | 2018-02-01 | 2019-08-09 | 李冰 | A kind of splicing optical waveguide structure and preparation method thereof |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070298330A1 (en) * | 2006-06-23 | 2007-12-27 | Industrial Technology Research Institute | Recticle pattern applied to mix-and-match lithography process and alignment method of thereof |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63148627A (en) * | 1986-12-12 | 1988-06-21 | Hitachi Ltd | Method of lithographing by electron beam lithography equipment |
JPH0367734A (en) * | 1989-08-04 | 1991-03-22 | Kimoto & Co Ltd | Copying car |
JP4011642B2 (en) | 1995-12-15 | 2007-11-21 | 株式会社日立製作所 | Electron beam drawing method and apparatus |
KR19980030438A (en) * | 1996-10-29 | 1998-07-25 | 김영환 | Semiconductor Vernier structure and method of measuring overlay accuracy using it |
JP3791484B2 (en) * | 2002-11-14 | 2006-06-28 | ソニー株式会社 | Exposure method and semiconductor device manufacturing method |
-
2011
- 2011-03-16 US US13/049,047 patent/US20120237857A1/en not_active Abandoned
- 2011-04-28 TW TW100114821A patent/TWI434135B/en active
- 2011-06-20 CN CN201110164983.9A patent/CN102681330B/en active Active
-
2013
- 2013-02-25 US US13/776,122 patent/US8535858B2/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070298330A1 (en) * | 2006-06-23 | 2007-12-27 | Industrial Technology Research Institute | Recticle pattern applied to mix-and-match lithography process and alignment method of thereof |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10249570B2 (en) * | 2012-06-28 | 2019-04-02 | Taiwan Semiconductor Manufacturing Company, Ltd. | Overlay mark |
US10424543B2 (en) | 2012-06-28 | 2019-09-24 | Taiwan Semiconductor Manufacturing Company, Ltd. | Overlay mark |
US11037882B2 (en) | 2012-06-28 | 2021-06-15 | Taiwan Semiconductor Manufacturing Company, Ltd. | Overlay mark |
US11876054B2 (en) | 2012-06-28 | 2024-01-16 | Taiwan Semiconductor Manufacturing Company, Ltd. | Overlay mark and method of making |
US20160322307A1 (en) * | 2015-04-28 | 2016-11-03 | Kabushiki Kaisha Toshiba | Method of forming mark pattern, recording medium and method of generating mark data |
US9741564B2 (en) * | 2015-04-28 | 2017-08-22 | Toshiba Memory Corporation | Method of forming mark pattern, recording medium and method of generating mark data |
US20180188646A1 (en) * | 2015-09-24 | 2018-07-05 | Korea Research Institute Of Standards And Science | Method for manufacturing transparent substrate and method for manufacturing surface enhanced raman scattering substrate using the same |
US10222695B2 (en) * | 2015-09-24 | 2019-03-05 | Korea Research Institute Of Standards And Science | Method for manufacturing transparent substrate and method for manufacturing surface enhanced Raman scattering substrate using the same |
CN109870876A (en) * | 2017-12-05 | 2019-06-11 | 长鑫存储技术有限公司 | A kind of alignment pattern production method |
Also Published As
Publication number | Publication date |
---|---|
TW201239515A (en) | 2012-10-01 |
US20130164689A1 (en) | 2013-06-27 |
US8535858B2 (en) | 2013-09-17 |
CN102681330B (en) | 2013-09-25 |
CN102681330A (en) | 2012-09-19 |
TWI434135B (en) | 2014-04-11 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8535858B2 (en) | Photomask and method for forming overlay mark using the same | |
US8143731B2 (en) | Integrated alignment and overlay mark | |
US20110315077A1 (en) | Template, manufacturing method, and processing method | |
KR102234133B1 (en) | Imprint method and imprint mold manufacturing method | |
JP2009231766A (en) | Mark forming method | |
US8288242B2 (en) | Overlay vernier key and method for fabricating the same | |
US7582395B2 (en) | Overlay mark | |
KR20110093495A (en) | Method for forming fine patterns of semiconductor device | |
KR20110001804A (en) | Method for measuring step variation of underlying layers using overlay vernier pattern | |
CN105161454A (en) | Array substrate and manufacturing method thereof, display apparatus | |
US20120214103A1 (en) | Method for fabricating semiconductor devices with fine patterns | |
JP2008096665A (en) | Photomask and method for manufacturing semiconductor device | |
JP2007258650A (en) | Transfer mask blank, transfer mask and pattern exposure method | |
JP2005175270A (en) | Mark for detecting displacement | |
US8729716B2 (en) | Alignment accuracy mark | |
KR101159689B1 (en) | Method for forming overlay vernier in semiconductor device | |
US20130252428A1 (en) | Photo-etching and Exposing System | |
CN113130303B (en) | Mask and triple patterning method | |
CN111508825B (en) | Device offset monitoring method, semiconductor device and manufacturing method thereof | |
KR20110101404A (en) | Method for manufacturing semiconductor device | |
KR20100076680A (en) | Method for fabricating phase shift mask | |
KR20130022677A (en) | Method for fabricating array of fine patterns in semiconductor device | |
KR100866725B1 (en) | Method for manufacturing fine pattern of a semiconductor device | |
KR20130067166A (en) | Method for fabricating a semiconductor device | |
JP2002311568A (en) | Phase shifting mask and its fabrication method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NANYA TECHNOLOGY CORPORATION, TAIWAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CHIU, CHUI FU;REEL/FRAME:025968/0411 Effective date: 20110311 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |