Method of forming a mask

Abstract

A method of fabricating a mask forms a rectangular opening within etch resistant material that overlays a substrate. The mask preferably comprises two layers of photoresist separated by a layer of light blocking material. One of the layers of photoresist is patterned per a longitudinal exposure strip, and the other per an overlap of a lateral exposure strip with the longitudinal exposure strip, so as to provide an opening for the mask where the two overlap. With this mask over a substrate, the substrate is etched to form a container therein with a rectangular cross-section corresponding to the aperture of the mask. The container is then lined with electrically conductive material, dielectric, and electrically conductive material respectively to form a capacitor in the container—e.g., a container-cell capacitor for a DRAM device.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a mask suitable for use in forming a container in a substrate, and more specifically to a mask having a fine geometry, rectangular opening that may be utilized to etch a substrate and define an opening or hole therein having an outline corresponding to the rectangular opening of the mask. Additionally, the present invention relates to a container-cell capacitor for a dynamic random access memory (DRAM).

[0002] An exemplary prior art dynamic random access memory (DRAM) device comprises an array of container-cell capacitors that are formed in a substrate. In the current application, the term “substrate” or “semiconductor substrate” will be understood to mean any construction comprising semiconductor material, including but not limited to bulk semiconductive materials such as a semiconductor wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). Further, the term “substrate” also refers to any supporting structure including, but not limited to, the semiconductive substrates described above.

[0003] One known container structure for the container-cell capacitors a memory array, comprises a container having a cylindrical or “bath-tub” shape. In a known method of fabricating a container in a substrate, with reference to FIGS. 1-3, a single layer of photoresist 12 is coated over layer 10 of, for example, borophosphosilicate glass (BPSG). Light 14, such as ultraviolet light, irradiates a select region 16 of photoresist 12 as determined by an exposure plate or reticle (not shown). Advancing to FIG. 2, photoresist 12 is developed to form opening 18. Opening 18 exposes surface 20 of layer 10. With this mask 12, layer 10 can be etched (e.g., by a reactive plasma etch) to form container 19 within layer 10, see FIG. 3. As used herein, the term “container” shall be inclusive of similar structural descriptors such as void, pocket, hole, contact opening, via and the like. A radius of curvature r1 of the container corresponds to the radius of curvature of opening 18 of mask 12. To form a capacitor, container 19 is lined with first conductive material, dielectric, and second conductive material layers respectively.

[0004] In order to minimize costs, manufactures of DRAM's strive to reduce the dimensions of the container-cell capacitors and increase the density of such cells within the array. Accordingly, some have developed a container-cell capacitor having a primarily rectangular cross-section for providing increased capacitance without sacrificing cell density. Referencing FIGS. 4A and 4B, such exemplary prior art container 19 comprises a cross-section of rectangular outline 23 offering an increase in the area of the container walls. This increased area, in-turn, increases electrode area and capacitance value of the container-cell over that which might otherwise be provided by an equivalent width cylindrical container 18.

[0005] In a prior art method of forming a mask with a rectangular aperture, referencing FIGS. 5A and 5B, insulating material 10, e.g., BPSG, is layered over a silicon wafer of a supporting substrate 21. Etch resistant material 96 is layered over insulating material 10. Etch resistant material 96 is capable of resisting an etchant that is used during subsequent etching of insulating material 10, and may comprise, e.g., nitride of about 1,000 angstroms thickness. Photoresist (not shown) is layered over the top of etch resistant material 96 and patterned to define lateral apertures therein. The lateral apertures of the photoresist are used to define lateral openings 100 into etch resistant material 96. After forming lateral openings 100 in etch resistant material 96, the first photoresist is removed.

[0006] Continuing with this particular, exemplary, prior art method, additional photoresist 94 is applied over the patterned etch resistant material 96. This new photoresist is patterned to define longitudinal openings 106 that overlap lateral openings 100, thereby defining rectangular openings 18 (FIG. 5B) at overlapping regions. Thereafter, select regions of substrate 21 are processed or etched in accordance with the openings to define containers 19. In this exemplary prior art method of forming a rectangular opening for a mask, the second photoresist is layered over the substrate and processed only after the first, lower photoresist has been fully processed. In other words, the lower photoresist is processed first, and only then is the upper layer of photoresist coated thereover and processed.

[0007] After forming this mask opening, the substrate is etched in accordance with the rectangular opening of the patterned photoresist and lower mask material, so as to provide a container within the substrate having primarily a rectangular cross-section corresponding to the rectangular opening of the mask.

[0008] In the above, exemplary, prior art method of forming a mask with a rectangular aperture, the upper photoresist is applied to the substrate only after the lower mask material has already been processed to define the lateral opening therein. In other words, the exemplary prior art sequence of steps comprises, in general, processing the first mask material, applying photoresist over the first mask material, followed by processing the photoresist. With this sequence of steps, the substrate is moved from, firstly, an etch or development station associated with processing the first mask material; to, secondly, a photoresist coat station for applying the photoresist over the processed mask material; and then back to, thirdly, an etch or resist development station to define the longitudinal openings in the photoresist. Recognizing a need in the manufacture of semiconductors to reduce handling and travel of wafers during semiconductor production flows, so as to reduce the time and costs associated with such wafer transport, the present invention proposes a new mask and method of manufacture thereof that can provide for effective and efficient semiconductor production flows.

[0009] Accordingly, the present invention provides a new mask and method of manufacture thereof, for use in forming a container for a container-cell capacitor having a rectangular cross-section, which mask and method of manufacture are capable of overcoming some of the above limitations. Furthermore, an array of containers are formed in a substrate by etching a substrate in accordance with fine geometry openings of such mask, providing for an efficient process flow.

SUMMARY OF THE INVENTION

[0010] In accordance with a first embodiment of the present invention, a method of forming a mask comprises layering radiation blocking material over a layer of first radiation sensitive material, such as photoresist. The radiation blocking material is patterned to provide a first opening therein that uncovers a portion of the layer of radiation sensitive material. Next, the layered structure is irradiated in accordance with an exposure pattern that overlaps a portion of the first opening, thereby irradiating a region of the lower radiation sensitive material. The radiation sensitive material is then developed to remove the irradiated region thereof and form an opening for the mask. In accordance with one aspect of this embodiment, a second layer of radiation sensitive material, e.g., photoresist, is layered over the layer of radiation blocking material and patterned to provide a longitudinal opening therein and uncover a corresponding region of the radiation blocking material. A visible portion of the radiation blocking material is removed using the patterned, second layer of radiation sensitive material as a mask, thereby forming the first opening in the radiation blocking material.

[0011] Preferably, the second layer of radiation sensitive material is provided a longitudinal opening, and the lower layer of radiation sensitive material is irradiated using a lateral exposure strip that overlaps the longitudinal opening.

[0012] In accordance with one aspect of the invention, a DARC (dielectric antireflective coat) layer is provided between the light blocking material and the second photoresist.

[0013] In a further embodiment of the present invention, a mask, as outlined above, is formed over a substrate. Again, the second layer of radiation sensitive material has been patterned to provide a longitudinal opening, and lower layer of radiation sensitive material irradiated using a lateral exposure strip that overlaps the longitudinal opening to provide for a rectangular overlap region. The exposed, rectangular overlap region is developed to provide a mask aperture having a rectangular outline. Through this mask aperture, select regions of the substrate are etched to form a container therein with a rectangular cross-section corresponding to the rectangular outline of the mask aperture.

[0014] In accordance with one aspect of this embodiment, a capacitor is formed within the container, thereby providing a container-cell capacitor with a rectangular cross-section.

[0015] In accordance with yet another embodiment of the present invention, a mask comprises a layer of first photoresist, a layer of light blocking material over the first photoresist, and second photoresist over the light blocking material. A dielectric antireflective coat (DARC) is provided over the light blocking material and beneath the second photoresist. In accordance with one aspect of this embodiment, at least one of the first and second photoresists is patterned per a longitudinal exposure strip, and the other per a lateral exposure strip. The first one comprises an opening corresponding to the longitudinal exposure strip, and the other an opening corresponding to an overlap of the longitudinal and lateral exposure strips.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be understood from reading the following description of particular embodiments, with reference to the attached drawings as illustrated below, where:

[0017] FIGS. 1-3 are partial, cross-sectional, isometric views representative of a known method of forming a known mask and cylindrical container;

[0018] FIGS. 4A-4B show planar and exploded views illustrating generally a mask over a substrate;

[0019] FIG. 5A provides a partially sectioned, isometric view of a prior art mask and container;

[0020] FIG. 5B is a planar view of FIG. 5A, illustrating generally a mask aperture over an underlying substrate;

[0021] FIGS. 6-10 provide exemplary, isometric and cross-sectional views illustrating generally fabrication of a mask in accordance with an embodiment of the present invention; and

[0022] FIGS. 11-14 provide exemplary cross-sectional isometric views illustrating, generally, fabrication of a container-cell capacitor in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention proposes a mask with a rectangular opening, and a new method of forming such mask which can facilitate an easy process flow that can be used, for example, in production of Dynamic Random Access Memory.

[0024] In accordance with an exemplary embodiment of the present invention, skipping forward with reference to FIG. 10, mask 12 comprises first and second layers 65,68 of radiation sensitive material separated by a layer 66 of radiation blocking material. In accordance with one aspect of this embodiment, layers 65,68 comprise known photoresist of about 0.5-1.0 pxn thickness and layer 66 comprises a metal, for example, aluminum, of less than 1000 angstroms thickness, and more preferably between 500 and 600 angstroms. In an alternative exemplary embodiment, referencing FIG. 6A, layer 66′ further comprises a dielectric antireflective coat (i.e., DARC) layered adjacent light blocking material 84. In one aspect of this exemplary embodiment, a DARC layer 85 is formed over the layer of radiation blocking material 84 and below photoresist 68. In a further aspect of this exemplary embodiment, a DARC layer 83 is also provided over photoresist 65 and beneath the layer of radiation blocking material 84. For these exemplary embodiments, DARC layer comprise a material and thickness—e.g., &agr;-Si or SixOyNz of about 200-1000 angstroms—appropriate for minimizing reflections of the associated process irradiation, e.g., ultraviolet light.

[0025] Turning to a method of forming such mask, with reference to FIGS. 6-11, first photoresist 65 is layered over substrate 21, with a thickness of about 3000-10,000 angstroms. Again, the term “substrate” or “semiconductor substrate” will be understood to mean any construction comprising semiconductor material, including but not limited to bulk semiconductive materials such as a semiconductor wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). Further, the term “substrate” also refers to any supporting structure including, but not limited to, the semiconductive substrates described above.

[0026] Further referencing FIG. 6, layer 66 comprises radiation (e.g., light) blocking material and is deposited over first photoresist 65. In an exemplary embodiment, the photoresist is sensitive to ultraviolet light and the radiation blocking material opaque to the ultraviolet light. In accordance with such embodiment, the radiation blocking material comprises a metal, for example, aluminum of 200-1,000 angstroms thickness. Next, another layer of photoresist 68 (preferably sensitive to ultraviolet light) is layered over layer 66 of the radiation blocking material.

[0027] As discussed above in accordance with certain exemplary embodiments, a dielectric antireflective coat 85 can be formed on the layer of radiation blocking material 84, as shown in FIG. 6A, for provision beneath photoresist 68. Additionally, a dielectric antireflective coat 83 might also be formed over photoresist 65 for provision beneath radiation blocking material 84.

[0028] Preferably, the material(s) of layer 66, or 66′, are formed over photoresist 65 under conditions preserving the integrity of lower photoresist 65. For example, the DARC and/or radiation blocking material layers should be deposited using known chemical vapor deposition or sputtering methods at temperatures less than 200° C.

[0029] With reference to FIG. 7, the upper layer of a photoresist 68 is irradiated 70, in a preferred embodiment using ultraviolet light, using a reticle (not shown) to pattern a longitudinal irradiated region or exposure strip 72 on photoresist 68. The irradiated region of the photoresist is developed to form longitudinal opening 74 therein as shown in FIG. 8. Opening 74 uncovers a corresponding surface region of layer 66 comprising radiation blocking material. Using the patterned, upper photoresist 68 as a mask, the uncovered region 76 of layer 66 is etched—e.g., using a reactive ion plasma 78—until reaching and uncovering a corresponding portion of the lower photoresist 65. In an exemplary embodiment, layer of radiation blocking material is etched using a known anisotropic etchant. Additionally, a brief isotropic finishing etch may be employed after the anisotropic etch so as to remove undesirable “stringers” or “slivers”, which may not have completely cleared the etch window of the preceding anisotropic etch.

[0030] Continuing with reference to FIG. 9, another exposure 82 irradiates a lateral exposure strip 80 of the layered substrate structure and exposes region 86 of lower photoresist 65. Exposed region 86 of photoresist 65 is defined by where lateral exposure strip 80 overlaps longitudinal opening 74. Preferably, lateral exposure strip 82 overlaps longitudinal opening 74 with its primary axis perpendicular to that of the longitudinal opening. The photoresist is then developed to remove its irradiated region 86, thereby providing mask 12 with an opening 18 as shown in FIG. 10. In accordance with an alternative exemplary embodiment, the upper layer of photoresist 68 can be removed (leaving light blocking material 66) before the exposure and patterning of the lower layer photoresist 65.

[0031] In the exemplary embodiment depicted by FIG. 10, opening 18 has a rectangular outline that exposes a corresponding region 92 of substrate 21. Accordingly, the select visible region 92 of substrate 21 can then be processed, as permitted through opening 18 of mask 12. In a particular exemplary embodiment, select region 92 of substrate 21 is etched through opening 18 of mask 12, so as to form a void, pocket, hole, contact opening, via or container (hereinafter container) within the substrate having an outline corresponding to that of mask opening 18. In alternative exemplary applications, mask 12 can be used during deposition or implant of the select region 92 of substrate 21.

[0032] Moving on to a particular, exemplary embodiment, with reference to FIG. 11, substrate 21 comprises a known silicon wafer 24 that has already been processed through some of the steps in the production of a dynamic random access memory. Field-oxide regions 25 isolate various active regions of wafer 24. Wordlines 26 are disposed across the surface of wafer 24. The wordlines comprise poly 32 covered with silicide 34, both encapsulated by insulating materials of cap 36 and sidewalls 38. Cap 36 and sidewalls 38 prevent the silicide 34 and poly 32 of wordlines 26 from contacting and electrically shorting to neighboring electrically conductive plugs 54,56,58. Diffusion nodes 30 have been doped to provide electrically conductive regions within silicon wafer 24. Plugs 54,56,58 comprise electrically conductive material which electrically interconnect to their respective diffusion nodes 30. Insulating materials 41,50,64 around the walls of plug 56, serve to insulate plug 56 from adjacent plugs 54,58. Insulating material 40, disposed above and between certain wordlines over the field-oxide isolation regions 25, serve to separate the various memory cell units from their adjacent other memory cell units. Insulating material 10 overlays wafer 24 and its various wordline and plug structures. In an exemplary embodiment, insulating material 10 comprises an oxide such as borophosphosilicate glass (BPSG) or tetraethylorthosilicate (TEOS) deposited silicon. Preferably, the outwardly facing surface 9 of insulating material 10 has been planarized, for example, by a known planarization proces such as chemical-mechanical-polishing (CMP).

[0033] Moving on to FIGS. 12-13, mask 12 (of a particular embodiment of the present invention as described above) is formed over substrate 21. An anisotropic plasma etch is used to etch exposed regions 92 of insulating material 10 of substrate 21. The etch continues sufficiently until exposing portions of plugs 58,54, thereby forming containers 19 of generally rectangular outlines 23 corresponding to the outlines of openings 18 of mask 12. Upon forming containers 19, mask 12 is removed.

[0034] The protective materials of cap 50 and spacers 64 are different from insulating material 10 so that insulating material 10 can be etched more favorably relative (selective to) cap 50 and spacers 64. Accordingly, the protective cap 50 and spacers 64 keep plug 56 isolated from the neighboring containers 19. In one exemplary embodiment, when insulating material comprises oxide, protective cap 50 and spacers 64 comprise nitride.

[0035] Continuing with reference to FIG. 14, electrically conductive material 110 is layered within containers 19, using a known deposition procedure. In an exemplary embodiment, conductive material 110 comprises hemispherical grain (HSG) polysilicon and is deposited before removal of mask 12. These conductive linings in containers 19 will serve as storage node electrodes for the resulting container-cell capacitors to be formed therein. Dielectric 111, for example, silicon nitride or tantalum pentoxide, is then deposited over conductive material 110. Finally, electrically conductive material 112 is deposited over dielectric 111, providing upper electrodes for capacitors 42,46. By way of the present invention, container-cell capacitors 42,46, have been formed in containers of rectangular or square cross-section, thereby providing greater electrode areas over that which would otherwise be available for cylindrical containers as represented by phantom lines 17 of FIG. 13.

[0036] U.S. patent application Ser. No. 09/076,324 entitled “Methods of Electrically Contacting to Conductive Plugs, Methods of Forming Contact Openings, and Methods of Forming Dynamic Random Access Memory Circuitry”, (97-1200), and U.S. Pat. Nos. 5,651,855 and 5,858,877, hereby incorporated by reference, provide exemplary known etching and deposition chemistries.

[0037] Accordingly, the present invention provides a mask and method of forming such mask with a fine geometry, rectangular aperture. Further, such mask can be used to form a container of rectangular cross-section within a substrate. Additionally, a container-cell capacitor can be formed within the container to provide a capacitor of electrode area and capacitance greater than that of a similar diameter cylindrical container.

[0038] Although the foregoing invention has been described in certain preferred embodiments, other embodiments will become apparent, in view of the disclosure herein. Accordingly, the scope of the invention is, therefore, indicated by the independent claims rather than by the foregoing description. All changes thereto which come within the meaning and range of the equivalency of the claims are to be embraced within the scope of the claims.

Claims

1. A mask comprising:

a first layer of photoresist;

a layer of radiation blocking material disposed over said first photoresist; and

a second layer of photoresist over said radiation blocking material.

2. A mask according to

claim 1, wherein said radiation blocking material comprises metal.

3. A mask according to

claim 2, wherein said metal has a thickness of at least 200 angstroms.

4. A mask according to

claim 2, further comprising a dielectric anti-reflective coating over said metal and beneath said second photoresist.

5. A mask according to

claim 4, wherein said dielectric anti-reflective coat comprises a material and thickness selected to be non-reflective of ultraviolet light.

6. A mask according to

claim 5, wherein at least one of said first and second photoresists has a thickness in a range of about 3,000-10,000 Å.

7. A mask according to

claim 5, wherein said dielectric anti-reflective coating has a thickness in the range of about 200-1,000 Å.

8. A mask according to

claim 5, wherein said first and said second photoresists are photosensitive to ultraviolet light.

9. A mask according to

claim 1, wherein said radiation blocking material comprises metal, said mask further comprising a dielectric anti-reflective coat over and against said metal.

10. A mask according to

claim 9, wherein said metal has a thickness less than about 1,000 angstroms

11. A mask according to

claim 1, wherein said first and said second photoresist layers have been patterned per a longitudinal exposure strip and a lateral exposure strip, one of said first and second photoresist layers having walls defining an opening corresponding to one of said longitudinal exposure strip and said lateral exposure strip, and the other of said first and said second photoresist layers having walls defining an opening therein corresponding to an overlap region of said longitudinal exposure strip and said lateral exposure strip.

12. A mask according to

claim 11, wherein at least one of said longitudinal and said lateral exposure strips has a width less than about 0.5 &mgr;m.

13. A mask according to

claim 11, wherein said radiation blocking material comprises walls defining an opening therein corresponding to one of said longitudinal and said lateral exposure strips.

14. A method of fabricating a mask, comprising:

providing a first layer of photoresist;

layering a radiation blocking material over said first layer of photoresist;

layering masking material over said radiation blocking material;

removing a region of said masking material and providing a first opening therein that reveals a portion of said radiation blocking material;

through said first opening, removing a portion of said radiation blocking material and uncovering a region of said first layer of photoresist;

irradiating with a light pattern, a portion of the uncovered region of said first layer of photoresist where said light pattern overlaps said first opening; and

removing said irradiated portion of the first layer of photoresist.

15. A method of fabricating a mask according to

claim 14, wherein said masking material comprises photoresist, and said step of removing a portion of said masking material comprises steps of:

irradiating said photoresist per a longitudinal exposure strip, and

removing the irradiated portion of said photoresist to define a longitudinal opening therein.

16. A method according to

claim 15, wherein at least one of said irradiating steps employs ultraviolet light.

17. A method according to

claim 15, wherein said light pattern for irradiating said furst layer of photoresist provides a lateral exposure strip overlapping the longitudinal opening.

18. A method according to

claim 17, wherein at least one of said longitudinal and said lateral exposure strips has an exposure width less than about 0.5 &mgr;m.

19. A method according to

claim 18, wherein said lateral exposure strip has a primary axis substantially perpendicular to a primary axis of said longitudinal opening.

20. A method according to

claim 15, wherein said step of removing a region of said radiation blocking material employs a step of anisotropic plasma etching.

21. A method according to

claim 14, wherein said layering of the radiation blocking material comprises the steps of:

forming a layer of metal over said first photoresist; and

forming a dielectric anti-reflective coating on said layer of metal.

22. A method according to

claim 21, wherein said layer of metal is formed with a thickness between 200 and 1,000 angstroms

23. A method of processing a substrate, comprising the steps of:

coating photoresist on said substrate;

forming light blocking material over said first photoresist;

coating photoresist over said light blocking material;

patterning said photoresist of said light blocking material to provide an opening therein that exposes a portion of said light blocking material corresponding to a first pattern;

through the opening in said photoresist, removing a portion of said light blocking material and uncovering a region of said first photoresist;

irradiating, in accordance with a second pattern, at least a portion of said uncovered region of said photoresist on said substrate;

developing and removing the irradiated portion of said photoresist on said substrate to form an aperture therein; and

processing a region of said substrate through said aperture.

24. A method according to

claim 23, wherein said step of patterning comprises:

irradiating a longitudinal strip of said photoresist, and

developing said photoresist layer to remove the irradiated longitudinal strip thereof, and form a longitudinal opening therein.

25. A method according to

claim 24, wherein said irradiatting with the second pattern irradiates with at least one lateral strip that overlaps said longitudinal opening.

26. A method according to

claim 25, wherein said lateral strip extends primarily perpendicular to said longitudinal opening.

27. A method according to

claim 23, wherein said etching of said substrate comprises anisotropic plasma etching to remove portions of said substrate through the aperture of the overlying photoresist.

28. A method according to

claim 23, wherein said step of irradiating employs ultraviolet light.

29. A method according to

claim 23, wherein said step of forming the light blocking layer comprises:

depositing metal against said photoresist; and

forming a dielectric anti-reflective coating on said metal.

30. A method according to

claim 29, in which said metal is provide a thickness of about 200 to 1,000 angstroms.

31. A method of fabricating a container cell capacitor for a semiconductor device, comprising the steps of:

providing a substrate having a layer of insulating material;

layering a first layer of photoresist over said insulating material;

forming a light blocking layer over said first layer of photoresist;

forming a second layer of photoresist over said light blocking layer;

irradiating a region of said second layer of photoresist in accordance with a first exposure pattern;

developing and removing the irradiated region of said second layer of photoresist to provide an opening therein corresponding to said first exposure pattern;

through said opening, removing a portion of said light blocking layer and uncovering a portion of said first layer of photoresist;

irradiating, in accordance with a second exposure pattern, a region of said uncovered portion of said first layer of photoresist;

developing and removing said irradiated region of said first layer of photoresist, to provide an opening therein that exposes a portion of said insulating material;

etching a portion of said insulating material through said opening of the first layer of photoresist, and forming a container therein; and

fabricating a capacitor within said container.

32. A method according to

claim 31, wherein said step of fabricating a capacitor comprises:

lining said container with electrically conductive material;

forming dielectric material on said electrically conductive material; and

depositing electrically conductive material over said dielectric material.

33. A method according to

claim 32,

wherein said first exposure pattern includes a longitudinal exposure strip and said step of firstly irradiating comprises irradiating with UV radiation a respective longitudinal exposure strip region of said second layer of photoresist, and

wherein said second exposure pattern includes a lateral exposure strip and said step of secondly irradiating comprises illuminating with UV radiation select regions of said second layer of photoresist and said uncovered first layer of photoresist per said at least one lateral exposure strip, said at least one lateral exposure strip overlapping and extending primarily perpendicular to said at least one longitudinal exposure strip.

34. A method according to

claim 33, wherein said at least one longitudinal exposure strip has a width less than about 0.5 &mgr;m.

35. A method according to

claim 34, wherein said at least one lateral exposure strip has a width less than about 0.5 &mgr;m.

36. A method according to

claim 35, wherein said step of etching the insulating material comprises anisotropic plasma etching.

37. A method according to

claim 36, wherein said insulating material has a given depth, and said step of etching comprises etching a portion of said insulating material to about said given depth.

38. A method according to

claim 37, further comprising a step of layering at least one of tetraethylorthosilicate (TEOS) silicon dioxide and borophosphosilicate glass (BPSG) over said substrate as said insulating layer.

39. A method according to

claim 31, wherein said step of forming the light blocking layer comprises the steps of: layering metal over said first layer of photoresist; and coating a dielectric anti-reflective material over said metal.

40. A method according to

claim 39, wherein said metal is provided a thickness between 200 and 1,000 angstroms.

41. A method according to

claim 40, in which the dielectric anti-reflective coat is formed with a thickness between 200 and 1,000 angstroms.

42. A method of forming a mask comprising the steps of:

coating photoresist over a substrate;

depositing masking material over said photoresist;

forming a longitudinal slot in said masking material and uncovering a region of said photoresist corresponding to said longitudinal slot;

irradiating a portion of said uncovered region of said photoresist; and

developing and removing the irradiated portion of said photoresist to provide a mask opening therein.

43. A method according to

claim 42, wherein said step of forming the longitudinal slot comprises the steps of:

coating a second layer of photoresist over said masking material;

patterning said second layer of photoresist and defining a longitudinal opening therein that exposes a corresponding region of said masking material; and

removing exposed regions of said masking material through the longitudinal opening of said second layer of photoresist.

44. A method according to

claim 43 further comprising a step of removing said second layer of photoresist before said step of irradiating.

45. A method according to

claim 44, wherein said step of irradiating employs an exposure pattern providing a lateral exposure strip that overlaps a portion of said longitudinal slot.

46. A method according to

claim 45, wherein said lateral exposure strip has a primary axis substantially perpendicular to that of said longitudinal slot.

47. A method according to

claim 46, wherein the overlap of said lateral exposure strip and said longitudinal slot define a rectangular region for the irradiated portion of said photoresist.

48. A method according to

claim 47, wherein said mask opening comprises a rectangular outline corresponding to the rectangular region that was defined by the overlap of said lateral exposure strip and said longitudinal slot, said method further comprising a step of etching said substrate through said mask opening and forming a container in said substrate having a cross-section corresponding to the rectangular outline of said mask opening.

49. A method according to

claim 43, further comprising a step of forming a dielectric antireflective coating over said masking material before said step of coating the second photoresist.

50. A method according to

claim 49, wherein said dielectric anti-reflective coating is selected to reduce reflection of UV light.

51. A method according to

claim 43, further comprising a step of providing an optical antireflective layer beneath at least one of said photoresists.

52. A method according to

claim 42, further comprising a step of etching said substrate through said mask opening.

53. A method according to

claim 42, wherein said masking material is opaque.

54. A method according to

claim 42, wherein said step of irradiating employs an exposure pattern that provides a lateral exposure strip that overlaps said longitudinal slot.

55. A method according to

claim 54, wherein said lateral exposure strip has a primary axis substantially perpendicular to that of said longitudinal slot.

56. A method according to

claim 55, wherein said lateral exposure strip overlaps said longitudinal slot to define a rectangular area for the irradiated portion of said photoresist.

57. A method of processing a substrate comprising the steps of:

providing a layer of first photoresist over a substrate;

providing a layer of light blocking material over said first layer of photoresist;

forming a longitudinal groove within said layer of light blocking material;

irradiating a lateral strip of said layered substrate and exposing a portion of said first photoresist where said lateral strip overlaps said longitudinal groove;

developing and removing the exposed portion of said first layer of photoresist so as to define a mask opening therein; and

processing a select region of said substrate, said select region defined in accordance with said mask opening.

58. A method according to

claim 57, wherein said lateral strip has a primary axis that is substantially perpendicular to that of said longitudinal groove.

59. A method according to

claim 57, wherein said step of processing comprises a step of etching the select region of said substrate.

60. A method according to

claim 59, in which said step of etching includes forming a container in said substrate, said container having a cross-section corresponding to an outline of the mask opening.

61. A method according to

claim 57, wherein said step of processing comprises doping the select region of said substrate.

62. A method according to

claim 57, wherein said step of forming a longitudinal groove comprises the steps of:

providing a second layer of photoresist over said light blocking material;

photolithographically processing said second layer of photoresist to define a longitudinal opening therein that exposes a corresponding portion of said light blocking material; and

removing exposed portions of said light blocking material through the longitudinal opening of said second layer of photoresist and providing said longitudinal groove.

63. A method according to

claim 62, further comprising a step of removing said second layer of photoresist before said step of irradiating the lateral strip of said layered substrate.

64. A method according to

claim 62, wherein said step of forming the longitudinal groove comprises uncovering a portion of said first layer of photoresist.

65. A method according to

claim 62, further comprising a step of providing a dielectric antireflective coating over said light blocking material and beneath said second layer of photoresist.

66. A method according to

claim 62, further comprising a step of providing a non-reflective layer beneath at least one of said first and said second photoresists.

67. A method according to

claim 66, wherein said nonreflective layer is selected to be non-reflective of ultraviolet light.

68. A method according to

claim 60, further comprising a step of forming a capacitor in said container.

69. A method according to

claim 68, wherein said step of forming a capacitor comprises:

lining said container with a first layer of conductive material;

forming dielectric conformably against said first layer of conductive material; and

depositing conductive material over said dielectric.

70. A method according to

claim 57, further comprising a step of planarizing said substrate.

71. A mask comprising:

a layer of photoresist, said photoresist having walls defining a rectangular opening therein; and

a layer of opaque material over said photoresist, walls of said opaque material defining a longitudinal groove through which a portion of said rectangular opening is visible.

72. A mask according to

claim 71, wherein a width of said rectangular opening is less than 0.5 &mgr;m, and said longitudinal groove comprises a length greater than said width.

73. A mask according to

claim 72, wherein said rectangular opening has a width less than 0.5 &mgr;m and a length less than 0.5 &mgr;m.

74. A mask according to

claim 71, wherein at least one wall of said mask opening is substantially perpendicular to at least one wall of said longitudinal groove.

75. A mask according to

claim 71, wherein said opaque material comprises radiation blocking material.

76. A mask according to

claim 75, further comprising a dielectric anti-reflective coating on said radiation blocking material.

77. A mask according to

claim 76, wherein said radiation blocking material comprises metal.

78. A mask according to

claim 76, wherein said radiation blocking material comprises metal of thickness less than 1000 Å, and said dielectric anti-reflective coating is selected to be nonreflective of ultraviolet light.

79. A mask according to

claim 71, wherein said layer of opaque material has a thickness and said longitudinal groove a depth up to said thickness.

80. A method of processing a substrate, comprising the steps of:

layering a substrate with a first layer of resist;

forming mask material over said first layer of resist, said mask material being opaque and having walls defining a groove;

forming an opening in said first layer of resist, said opening visible through the groove of said mask material; and

treating a select region of said substrate through said opening.

81. A method according to

claim 80, in which said treating comprises a step of implanting the select region of said substrate.

82. A method according to

claim 80, in which said treating comprises a step of removing a portion of said substrate defined in accordance with said opening.

83. A method according to

claim 82, wherein said step of removing includes etching.

84. A method according to

claim 82, wherein said step of removing includes a step of anisotropic plasma etching.

85. A method according to

claim 80, wherein said treating comprises the steps of:

exposing a region of said substrate to an anisotropic plasma, said region defined by said opening of the first layer of resist; and

etching a portion of said substrate exposed to said plasma to form a container therein with an outline defined by said opening.

86. A method according to

claim 85, further comprising a step of forming a capacitor in said container.

87. A method according to

claim 80, in which said groove has a width less than 0.5 &mgr;m.

88. A method according to

claim 87, in which said opening has a width substantially equal to that of said groove.

89. A method according to

claim 88, wherein said opening is formed with a pair of walls substantially perpendicular to a primary axis of said groove.

90. A method according to

claim 80, wherein said mask material comprises metal.

91. A method according to

claim 90, further comprising the steps of:

forming a second layer of photoresist over said metal;

patterning said second layer of photoresist to define a slot; and

etching a portion of said metal through said slot to provide said groove.

92. A method of fabricating a capacitor for a DRAM device, comprising the steps of:

providing a semiconductor substrate;

forming a layer of insulating material over said substrate,

forming a first layer of photoresist over said insulating material;

forming a layer of mask material over said first layer of photoresist;

forming a first groove in said layer of mask material and uncovering a corresponding region of said first layer of photoresist;

exposing per a radiation pattern a portion of the uncovered region of said first layer of photoresist;

developing and removing the irradiated portion of said first layer of photoresist to provide an aperture therein;

etching a region of said insulating material in accordance with said aperture to form a container in said layer of insulating material; and

forming a capacitor within said container.

93. A method according to

claim 92, wherein said step of forming the capacitor comprises the steps of:

lining said container with a conformal layer of electrically conductive material;

forming dielectric conformably over said electrically conductive material; and

depositing electrically conductive material over said dielectric.

94. A method according to

claim 92, wherein said step of exposing per the radiation pattern comprises irradiating with a strip of light substantially perpendicular to said first groove.

95. A method according to

claim 92, wherein said first layer of photoresist is selected to be photosensitive to ultraviolet light.

96. A method according to

claim 95, wherein said layer of mask material comprises photoresist.

97. A method according to

claim 92, wherein said forming the groove in said layer of mask material comprises the steps of.

layering photoresist over said layer of mask material;

patterning the photoresist to form a longitudinal slot therein; and

removing portions of said layer of mask material using the patterned photoresist as a mask to form said groove in said layer of mask material, said groove formed with an outline defined in accordance with the longitudinal slot of the patterned photoresist.

98. A method according to

claim 97, further comprising a step of removing the patterned photoresist before said step of exposing the first layer of photoresist.

99. A method according to

claim 92, wherein said mask material is selected to be opaque to ultraviolet light, and said first photoresist is selected to be photosensitive to ultraviolet light.