WO1994024608A2 - Method of preparation of mask for ion beam lithography - Google Patents
Method of preparation of mask for ion beam lithography Download PDFInfo
- Publication number
- WO1994024608A2 WO1994024608A2 PCT/US1994/003628 US9403628W WO9424608A2 WO 1994024608 A2 WO1994024608 A2 WO 1994024608A2 US 9403628 W US9403628 W US 9403628W WO 9424608 A2 WO9424608 A2 WO 9424608A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- substrate
- mask
- ion beam
- front side
- oxide
- Prior art date
Links
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
- G03F1/20—Masks or mask blanks for imaging by charged particle beam [CPB] radiation, e.g. by electron beam; Preparation thereof
Definitions
- the present invention relates to ion beam lithography. More particularly, the invention relates to an improved mask for ion beam lithography and a method for the manufacture thereof.
- Ion beam lithography has become an important tool in microelectronics when such circuits are required.
- ion charge particles is an alternative advanced microlithography approach.
- the ion beam imaging combines several inherent advantages: high-resolution beams, a possibility to influence its path by a magnetic field, a very low energy scatter and high energy levels of up to 150keV.
- a main advantage of using ion beams over electron beams is the lack of backscattered and hence minimum proximity effect.
- a problem which exists in masked ion beam lithography is a result of the pattern-dependent thermally induced distortions.
- the energy of the beam being absorbed in the mask will result its heating.
- this will effectively decrease the throughput by limiting the beam current density.
- a membrane mask having a thin membrane to self-support the pattern.
- a thin amorphous membrane, sufficiently transparent for the ions, or a channelling film of crystalline silicon are suggested for this use.
- the membrane supports an ion- absorbing layer of gold. The ions are scattered in the amorphous membrane and this will degrade the overall performance.
- the main problem encountered in the method for the manufacture of ion beam mask relates to the production of a thin and strong membrane capable to withstand dimensional stability and providing accuracy of the absorber pattern.
- This problem is solved by using a silicon membrane and exposing the resist in the channelling direction.
- residual scattering of ions in the mask membrane still exists even in the channelling of silicon membrane.
- This disadvantage is completely eliminated in an open-stencil mask, wherein a thin membrane with transmission holes is etched through the entire membrane thickness.
- a grid is provided as a support, consisting of a matrix of small transmission holes instead of completely open transmission areas. In this manner, most of the pattern restrictions associated with the stencil masks are eliminated.
- this grid increases significantly the mask area from which scattered ions may escape; furthermore, this type of mask will require a higher fluence to accomplish an exposure than simple stencil masks.
- SlffiS ITUTE SHEET (RULE 26) the manufacture thereof. It is another object of the present invention to provide an improved ion beam lithography mask which is highly stable, being substantially free of any stresses encountered in such known masks.
- the invention consists of a method for the manufacture of an improved mask for ion beam lithography, comprising the steps of: (a) coating a substrate by an insulating layer; (b) opening a window on the front side of the substrate; (c) depositing an oxide layer on the front side of the substrate; (d) opening a portion of the insulating layer; (e) patterning the oxide layer by ion beam photoresist and etching techniques, and (f) removal of a portion of the substrate from the backside, thus leaving a stenciled oxide mask resting on the substrate frame.
- the mask produced is characterized by its durability, ensuring a membrane flatness and siffness capable to prevent any feature displacement during its use.
- Membranes are usually supported on a more massive ring to ensure structural strength. It is important to have a close match between the thermal expansion coefficients of the ring and the membrane. As known, a film with a high elastic modulus is necessary to minimize local distortions of the pattern due to stresses. Low residual stresses are most desirable in order to avoid distortion of the membrane after a portion of it is removed to make a stencil.
- the main properties required for a material to be useful as membrane are: Young modulus and coefficient of thermal expansion. Most preferred materials are silicon, alumina and gold possessing the following main properties: The material Thermal expansion Young Modulus
- Aluminiun oxide exhibits a most interesting combination of thermal and mechanical properties: its thermal coefficeint of expansion is between those of silica and gold and its Young's modulus is high. Finally, alumina exhibits an extremely low etch rate in ion beam milling. This last property is of great significance for ion projection lithography since it indicates extremely good durability in ion beams.
- the attached Figure 1 illustrates in a schematic manner a first embodiment according to the present invention.
- the wafer used in step (a) as substrate is preferably silicon having a thickness of two inch, providing the frame of the mask.
- other materials such as copper may also be considered as substrate.
- this substrate is coated with an insulating layer in order to open a window on the front side.
- an insulating layer examples include waxes, lacquers, photoresists and most preferred are thermally grown silica, which are etched to form a window for the membrane. This membrane will be used as a mask for etching the central area of the silicon wafer.
- an oxide layer is deposited on the front side of the substrate either by electron-beam evaporation or sputtering.
- This layer is selected from aluminum, titanium, silicon and zirconium.
- Aluminum is the most preferred due to its thermal and mechanical properites.
- the alumina films which are formed are characterized by the following beneficial properties: are strong, exhibits a high elastic modulus, have the required minimal tensile strength, exhibits little scattering and can withstand high ion fluences.
- a further important advantage of alumina is the optical transparency which allows an easy alignment and low residual stresses. However, a slight tensile strength is required in order to keep the membrane flat.
- a most preferred method for obtaining the metal oxide layer is by a complete anodization of the front side of the substrate.
- a portion of the insulating material is opened in order to obtain a window.
- the oxide layer is patterned by ion beam photoresist and etching techniques.
- a portion of the substrate from the backside is removed by selective etching reagent thus leaving an open-stencil alumina mask.
- a preferred reagent for this purpose is boiling hydrazine which does attack only silicon, but not alumina or silicon oxide.
- the ion beam mask is provided with a gold absorber. This was found to be most useful in case of a stronger beam, obtaining a better absorption than without the gold presence.
- the thickness of the gold layer should be in the range of 0.1 to 5 ⁇ and most preferably in the range of between 0.5 and 3.5 ⁇ .
- the mask comprises the four steps as descirbe above followed by the following additonal steps:
- a thin layer of gold is spread onto the anodized layer using an adhesive medium such as evaporated titanium.
- an adhesive medium such as evaporated titanium.
- the gold spreading is carried out by sputtering which will avoid the requirement of the evaporated titanium.
- a photoresist is applied and the ' electron beam technology may be applied in order to obtain submicron dimensions.
- the gold is etched in a dry medium, using an ion beam milling in an argon environment. The dry etching is preferred since it will reduce undercutting and would retain the submicron features.
- the exposed silicon is selectively etched, using a know etchant, such as hydrazine, thus leaving an alumina-gold stencil mask.
- a know etchant such as hydrazine
- the ion beam that dislodge the atoms of the incident solid must have a substantially uniform density, being of the same wavelength of energy.
- the pressure should be low enough in order to prevent beam scattering and back sputtering.
- the ion beam mask produce according to the present invention may be considered as a non-optical alternative to obtain submicron images without moving to electron-beam imaging. While the invention has been described with reference to some particular embodiments, those skilled in the art will recognize that minor changes can be made in from and detail without departing from the spirit and scope of the invention as covered by the appended Claims.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Preparing Plates And Mask In Photomechanical Process (AREA)
- Electron Beam Exposure (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU66998/94A AU6699894A (en) | 1993-04-04 | 1994-04-04 | Method of preparation of mask for ion beam lithography |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IL105,299 | 1993-04-04 | ||
IL105299A IL105299A0 (en) | 1993-04-04 | 1993-04-04 | Ion beam lithography mask and a method for its preparation |
Publications (2)
Publication Number | Publication Date |
---|---|
WO1994024608A2 true WO1994024608A2 (en) | 1994-10-27 |
WO1994024608A3 WO1994024608A3 (en) | 1994-12-08 |
Family
ID=11064709
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1994/003628 WO1994024608A2 (en) | 1993-04-04 | 1994-04-04 | Method of preparation of mask for ion beam lithography |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU6699894A (en) |
IL (1) | IL105299A0 (en) |
WO (1) | WO1994024608A2 (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4021276A (en) * | 1975-12-29 | 1977-05-03 | Western Electric Company, Inc. | Method of making rib-structure shadow mask for ion implantation |
US4417946A (en) * | 1979-06-01 | 1983-11-29 | International Business Machines Corporation | Method of making mask for structuring surface areas |
-
1993
- 1993-04-04 IL IL105299A patent/IL105299A0/en unknown
-
1994
- 1994-04-04 WO PCT/US1994/003628 patent/WO1994024608A2/en active Application Filing
- 1994-04-04 AU AU66998/94A patent/AU6699894A/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4021276A (en) * | 1975-12-29 | 1977-05-03 | Western Electric Company, Inc. | Method of making rib-structure shadow mask for ion implantation |
US4417946A (en) * | 1979-06-01 | 1983-11-29 | International Business Machines Corporation | Method of making mask for structuring surface areas |
Also Published As
Publication number | Publication date |
---|---|
WO1994024608A3 (en) | 1994-12-08 |
AU6699894A (en) | 1994-11-08 |
IL105299A0 (en) | 1993-08-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP2527890B2 (en) | Mask, manufacturing method thereof, and method of laser processing target substrate | |
US5464711A (en) | Process for fabricating an X-ray absorbing mask | |
US6596465B1 (en) | Method of manufacturing a semiconductor component | |
US5567551A (en) | Method for preparation of mask for ion beam lithography | |
US6051346A (en) | Process for fabricating a lithographic mask | |
US4994141A (en) | Method of manufacturing a mask support of SiC for radiation lithography masks | |
US4634643A (en) | X-ray mask and method of manufacturing the same | |
CA1143483A (en) | X-ray lithography at 100 d linewidths using x-ray masks fabricated by shadowing techniques | |
JP3210143B2 (en) | X-ray mask structure, method for manufacturing the same, X-ray exposure method using the X-ray mask structure, and device manufacturing method using the X-ray mask structure | |
JPH10275773A (en) | Film mask for lithography by short-wavelength radiation | |
JP2609538B2 (en) | Reflective mask | |
US6897140B2 (en) | Fabrication of structures of metal/semiconductor compound by X-ray/EUV projection lithography | |
WO1994024608A2 (en) | Method of preparation of mask for ion beam lithography | |
US5178975A (en) | High resolution X-ray mask having high aspect ratio absorber patterns | |
JPH0430737B2 (en) | ||
JP2002217094A (en) | Mask for electron beam exposure and its manufacturing method | |
JPH0316116A (en) | Mask structure for x-ray lithography and x-ray exposure using mask structure | |
JPH02252229A (en) | X-ray exposure mask and its manufacture | |
Shimkunas et al. | Mask technology for x-ray step-and-repeat system | |
JPH05102013A (en) | X-ray mask structure body, its manufacture and x-ray exposure method using the same x-ray mask structure body | |
JP3195328B2 (en) | X-ray mask and method of manufacturing X-ray mask | |
JPS63115332A (en) | Mask for x-ray exposure | |
JPH04315417A (en) | Mask for long wavelength x-ray aligner and manufacture thereof | |
JP2886573B2 (en) | X-ray mask and manufacturing method thereof | |
JP3044742B2 (en) | X-ray exposure mask and method of manufacturing the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): AU BB BG BR BY CA CN CZ FI HU JP KP KR KZ LK LV MG MN MW NO NZ PL RO RU SD SI SK TT UA US UZ VN |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG |
|
AK | Designated states |
Kind code of ref document: A3 Designated state(s): AU BB BG BR BY CA CN CZ FI HU JP KP KR KZ LK LV MG MN MW NO NZ PL RO RU SD SI SK TT UA US UZ VN |
|
AL | Designated countries for regional patents |
Kind code of ref document: A3 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
WD | Withdrawal of designations after international publication |
Free format text: AU,BB,BG,BR,BY,CN,CZ,FI,HU,KP,KR,KZ,LK,LV,MG,MN,MW,NO,NZ,PL,RO,RU,SD,SI,SK,TT,UA,US,UZ,VN, OAPI PATENT(BF,BJ,CF,CG,CI,CM,GA,GN,ML,MR,NE,SN,TD,TG) |
|
122 | Ep: pct application non-entry in european phase | ||
NENP | Non-entry into the national phase |
Ref country code: CA |