Patent Application
20130040246
1. Field of Invention
The invention relates to a method and system for patterning a substrate, and more particularly to a method and system for preparing a pattern in a layer on a substrate.
2. Description of Related Art
In material processing methodologies, pattern etching comprises the application of a layer of radiation-sensitive material, such as photo-resist, to an upper surface of a substrate, the formation of a pattern in the layer of radiation-sensitive material using lithography, and the transfer of the pattern formed in the layer of radiation-sensitive material to an underlying thin film on the substrate using an etching process. The patterning of the radiation-sensitive material generally involves exposure of the radiation-sensitive material to a pattern of electromagnetic (EM) radiation using, for example, a lithography system, followed by the removal of the irradiated regions of the radiation-sensitive material (as in the case of positive tone resist), or non-irradiated regions (as in the case of negative tone resist) using a developing solution.
As the critical dimension (CD) decreases and the aspect ratio of the patterns formed in a layer of radiation-sensitive material increases, the potential for pattern defects including, but not limited to, pattern collapse, line edge roughness (LER), and line width roughness (LWR), becomes increasingly enhanced. In most situations, excessive pattern defects are unacceptable and, in some instances, catastrophic.
The invention relates to a method and system for preparing a pattern in a layer on a substrate, and more particularly to a method and system for preparing a pattern formed in a layer on a substrate having reduced pattern defectivity. The invention further relates to a method and system for treating a pattern formed in a layer on a substrate to reduce pattern collapse and pattern deformities, such as line edge roughness (LER) and line width roughness (LWR).
According to one embodiment, a method for patterning a substrate is described. The method includes forming a layer of radiation-sensitive material on the substrate, exposing the layer of radiation-sensitive material to electromagnetic (EM) radiation according to an image pattern, and developing the layer of radiation-sensitive material to form a pattern therein from the image pattern. The method further includes rinsing the substrate with a rinse solution, performing a first chemical treatment following the rinsing, wherein the first chemical treatment includes a first chemical solution, and performing a second chemical treatment following the rinsing, wherein the second chemical treatment includes a second chemical solution, the second chemical solution having a different chemical composition than the first chemical solution.
According to another embodiment, a system for patterning a substrate is described. The system includes a substrate table for supporting and rotating a substrate mounted thereon, a rinse solution supply nozzle for dispensing a rinse solution onto the substrate, and a rinse solution supply system for supplying the rinse solution to the first nozzle. The system further includes a first chemical treatment solution supply nozzle for dispensing a first chemical solution onto the substrate, a first chemical treatment solution supply system for supplying the first chemical solution to the first chemical treatment solution supply nozzle, a second chemical treatment solution supply nozzle for dispensing a second chemical solution onto the substrate, and a second chemical solution supply system for supplying the second chemical solution to the second chemical treatment solution supply nozzle.
According to yet another embodiment, a track system for patterning a substrate is described. The track system includes a coating module and a process module. The process module includes a substrate table for supporting and rotating a substrate mounted thereon, a rinse solution supply nozzle for dispensing a rinse solution onto the substrate, and a rinse solution supply system for supplying the rinse solution to the first nozzle. The process module further includes a first chemical treatment solution supply nozzle for dispensing a first chemical solution onto the substrate, a first chemical treatment solution supply system for supplying the first chemical solution to the first chemical treatment solution supply nozzle, a second chemical treatment solution supply nozzle for dispensing a second chemical solution onto the substrate, and a second chemical solution supply system for supplying the second chemical solution to the second chemical treatment solution supply nozzle.
In the accompanying drawings:
A method and system for patterning a substrate is disclosed in various embodiments. However, one skilled in the relevant art will recognize that the various embodiments may be practiced without one or more of the specific details, or with other replacement and/or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention.
Similarly, for purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the invention. Nevertheless, the invention may be practiced without specific details. Furthermore, it is understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.
Reference throughout this specification to “one embodiment” or “an embodiment” or variation thereof means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, but do not denote that they are present in every embodiment. Thus, the appearances of the phrases such as “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.
Nonetheless, it should be appreciated that, contained within the description are features which, notwithstanding the inventive nature of the general concepts being explained, are also of an inventive nature.
“Substrate” as used herein generically refers to the object being processed in accordance with embodiments of the invention. The substrate may include any material portion or structure of a device, particularly a semiconductor or other electronics device, and may, for example, be a base substrate structure, such as a semiconductor wafer or a layer on or overlying a base substrate structure such as a thin film. Thus, substrate is not intended to be limited to any particular base structure, underlying layer or overlying layer, patterned or unpatterned, but rather, is contemplated to include any such layer or base structure, and any combination of layers and/or base structures. The description below may reference particular types of substrates, but this is for illustrative purposes only and not limitation.
To increase productivity in lithographic patterning for semiconductor manufacturing, for example, a method and system are described to address some or all of the above-described circumstances. In particular, it is important to rinse the pattern in the substrate following pattern developing, and to dry the substrate without causing pattern collapse and pattern deformities having excessive variation in the pattern edge and/or width, and to reduce remaining precipitation-based defects.
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,
The layer of radiation-sensitive material may be formed by spin-coating the material onto the substrate. The layer of radiation-sensitive material may be formed using a track system. For example, the track system can comprise a Clean Track ACT® 8, ACT® 12, LITHIUS®, LITHIUS Pro™, or LITHIUS Pro V™ resist coating and developing system commercially available from Tokyo Electron Limited (TEL). Other systems and methods for forming a photo-resist film on a substrate are well known to those skilled in the art of spin-on resist technology. The coating process may be followed by one or more post-application bakes (PAB) to heat the substrate and one or more cooling cycles to cool the substrate following the one or more PABs.
In 120, the layer of radiation-sensitive material is exposed to electromagnetic (EM) radiation according to an image pattern. The radiation exposure system may include a dry or wet photo-lithography system. The image pattern may be formed using any suitable conventional stepping lithography system, or scanning lithography system. For example, the photo-lithography system is commercially available from ASML Netherlands B.V. (De Run 6501, 5504 DR Veldhoven, The Netherlands), or Canon USA, Inc., Semiconductor Equipment Division (3300 North First Street, San Jose, Calif. 95134). Alternatively, the image pattern may be formed using an electron beam lithography system.
In 130, the layer of radiation-sensitive material is developed to form a pattern therein from the image pattern. The pattern may be characterized by a nominal critical dimension (CD), a nominal line edge roughness (LER), and/or a nominal line width roughness (LWR). The pattern may include a line pattern. The developing process can include exposing the substrate to a developing solution in a developing system, such as a track system. For example, the developing solution may include tetramethyl ammonium hydroxide (TMAH). Alternatively, for example, the developing solution may include other alkaline solutions, such as a sodium hydroxide solution, a potassium hydroxide solution, etc. Additionally, for example, the track system can comprise a Clean Track ACT® 8, ACT® 12, LITHIUS®, LITHIUS Pro™, or LITHIUS Pro V™ resist coating and developing system commercially available from Tokyo Electron Limited (TEL). The developing process may be preceded by one or more post-exposure bakes (PEB) to heat the substrate and one or more cooling cycles to cool the substrate following the one or more PEBs.
In 140, the substrate is rinsed with a rinse solution. The rinse solution may include water, such as deionized (DI) water, or an aqueous solution containing a surfactant dissolved in water. The rinse solution may be used to displace and/or remove residual developing solution from the substrate. Preferably, the rinse solution contains only water. When the rinse solution contains only water (without surfactant), variations in the nominal CD may be prevented or minimized. After the developing process, the presence of developing solution on the pattern causes swelling of the pattern and increased permeability. As a result, when the rinse solution contains a surfactant, the rinse solution permeates into the pattern more freely, thus, causing variations in the nominal CD. In other words, rinsing the pattern on the substrate with only water, performed prior to additional chemical treatment, replaces the developing solution on the substrate with water and washes away the developing solution, thus, restraining variation in the nominal CD.
In 150, multiple chemical treatments are performed following the rinsing of the substrate to reduce and/or improve pattern collapse and pattern deformities, such as line edge roughness (LER) and line width roughness (LWR).
During the performing of the multiple chemical treatments, in 152, a first chemical treatment is performed following the rinsing, wherein the first chemical treatment includes a first chemical solution. The first chemical solution may include a first surfactant solution. The first chemical solution may include an anionic, a nonionic, a cationic, and/or amphoteric surfactant. Suitable anionic surfactants include sulfonates, sulfates, carboxylates, phosphates, and mixtures thereof. Suitable cationic surfactants may include: alkali metals, such as sodium or potassium; alkaline earth metals, such as calcium or magnesium; ammonium; or substituted ammonium compounds, including mono-, di- or tri-ethanolammonium cation compounds; or mixtures thereof.
As an example, the first chemical solution may include an aqueous solution containing a polyethylene glycol-based or acetylene glycol-based surfactant having a molecular weight of 1600 or less and a carbon number of its hydrophobic group of 10 or greater. It may be desirable that the hydrophobic group of the surfactant is not double-bonded or triple-bonded.
As another example, the first chemical composition may include one or more surfactant solutions selected from the FIRM™ family of surfactants (e.g., FIRM™-A, FIRM™-B, FIRM™-C, FIRM™-D, FIRM™ Extreme 10, etc.) co-developed by Tokyo Electron Limited (TEL) and Clariant (Japan) KK (Bunkyo-ku, Tokyo, Japan) (a subsidiary of Swiss manufacturer Clariant).
As another example, the first chemical composition may include a mixture of an amine compound and a surfactant.
As yet another example, the first chemical composition for the first chemical solution may be selected to reduce pattern collapse.
In 154, a second chemical treatment is performed following the rinsing, wherein the second chemical treatment includes a second chemical solution. The second chemical solution has a different chemical composition than the first chemical solution. In other words, the second chemical solution has a different elemental composition, i.e., atomic and/or molecular composition, than the first chemical solution.
The second chemical solution may include a second surfactant solution. The second chemical solution may include an anionic, a nonionic, a cationic, and/or amphoteric surfactant. Suitable anionic surfactants include sulfonates, sulfates, carboxylates, phosphates, and mixtures thereof. Suitable cationic surfactants may include: alkali metals, such as sodium or potassium; alkaline earth metals, such as calcium or magnesium; ammonium; or substituted ammonium compounds, including mono-, di- or tri-ethanolammonium cation compounds; or mixtures thereof.
As an example, the second chemical solution may include an aqueous solution containing a polyethylene glycol-based or acetylene glycol-based surfactant having a molecular weight of 1600 or less and a carbon number of its hydrophobic group of 10 or greater. It may be desirable that the hydrophobic group of the surfactant is not double-bonded or triple-bonded.
As another example, the second chemical composition may include one or more surfactants selected from the FIRM™ family of surfactants (e.g., FIRM™-A, FIRM™-B, FIRM™-C, FIRM™-D, FIRM™ Extreme 10, etc.) co-developed by Tokyo Electron Limited (TEL) and Clariant (Japan) KK (Bunkyo-ku, Tokyo, Japan) (a subsidiary of Swiss manufacturer Clariant).
As another example, the first chemical composition may include a mixture of an amine compound and a surfactant.
As yet another example, the second chemical composition for the second chemical solution may be selected to reduce pattern deformities, such as line edge roughness (LER) and/or line width roughness (LWR).
Referring now to
Then, in 253A, the substrate is rinsed with a second rinse solution. The second rinse solution may include water, such as deionized (DI) water, or an aqueous solution containing a surfactant dissolved in water.
Thereafter, in 254A, a second chemical treatment is performed following the rinsing of the substrate with the rinse solution and the rinsing of the substrate with the second rinse solution. As described above, the second chemical treatment includes a treatment with a second chemical solution.
As illustrated in
Then, in 254B, a second chemical treatment is performed following the rinsing of the substrate with the rinse solution. As described above, the second chemical treatment includes treatment with a second chemical solution.
Thereafter, in 256B, a third chemical treatment is performed following the rinsing of the substrate with the rinse solution. The third chemical treatment includes treatment with a third chemical solution.
As illustrated in
In 253C, the substrate is rinsed with a second rinse solution. The second rinse solution may include water, such as deionized (DI) water, or an aqueous solution containing a surfactant dissolved in water.
Then, in 254C, a second chemical treatment is performed following the rinsing of the substrate with the rinse solution. As described above, the second chemical treatment includes treatment with a second chemical solution.
In 255C, the substrate is rinsed with a third rinse solution. The third rinse solution may include water, such as deionized (DI) water, or an aqueous solution containing a surfactant dissolved in water.
Thereafter, in 256C, a third chemical treatment is performed following the rinsing of the substrate with the rinse solution. The third chemical treatment includes treatment with a third chemical solution.
As shown in
Inspection of
As an example,
In
The collapse margin improved CD is measured as a difference between a minimum printable CD achieved without performing any chemical treatment (i.e., the nominal CD for the pattern) and a minimum printable CD achieved when performing the chemical treatment. Therefore, inspection of
As an example,
As another example, a line pattern was prepared in a first EUV resist without any chemical treatment following developing and rinsing of the line pattern. The nominal CD for a first exposure condition was 28.5 nm with a nominal LWR of about 6.2 nm. When the line pattern was chemically treated with FIRM™ Extreme 10, a new line pattern was produced with a CD of 30.6 nm and an LWR of 6.0 nm. Furthermore, treatment of the line pattern with FIRM™ Extreme 10 following other exposure conditions resulted in improvement to the collapse margin, measured as a collapse margin improved CD of about 4 nm.
As yet another example, a line pattern was prepared in a second EUV resist without any chemical treatment following developing and rinsing of the line pattern. The nominal CD for a first exposure condition was 26.4 nm with a nominal LWR of about 4.2 nm. When the line pattern was chemically treated with FIRM™ Extreme 10, a new line pattern was produced with a CD of 27.7 nm and an LWR of 3.7 nm. Furthermore, treatment of the line pattern with FIRM™ Extreme 10 following other exposure conditions resulted in improvement to the collapse margin, measured as a collapse margin improved CD of about 6 nm.
Referring now to
System 530 includes a housing 501, and a fan-filter unit F that is provided at a ceiling of housing 501 for producing a downward flow of clean air into housing 501. System 530 is provided with a circular cup CP that is located at approximately a central portion of housing 501, and a substrate table 512 disposed within circular cup CP. The substrate table 512 is configured to support and rotate a substrate W mounted thereon. As an example, the substrate table 512 may securely hold substrate W by vacuum suction. A rotary drive system 513 is coupled to the substrate table 512, and configured to rotate the substrate table 512. The rotary drive system 513 may be attached to a base plate 514 of housing 501.
Inside the circular cup CP, lift pins 515 are arranged to raise and lower substrate W to and from substrate table 512. The lift pins 515 may rise and lower by means of a drive mechanism 516, such as a pneumatic cylinder or the like. Additionally, inside the circular cup CP, a drain port 517 may be provided for draining excess fluid. A drain pipe 518 is coupled to the drain port 517, and the drain pipe 518 passes through a space N between the base plate 514 and the housing 501, as shown in
Through a side wall of housing 501, an opening 501A is formed to allow a substrate carrier arm T of an adjacent substrate carrier unit (not shown) to access an interior space of housing 501. The opening 501A may be opened and closed by means of a shutter 519. When the substrate W is carried into and out of housing 501, the shutter 519 is opened so that the substrate carrier arm T may enter housing 501. The substrate W may then be transferred between the substrate carrier arm T and the substrate table 512 with the raising and lowering of lift pins 515.
As shown in
The rinse solution may include deionized (DI) water, or solution containing a surfactant dissolved in water.
The developing solution supply nozzle 525 may be constructed in an elongated shape and arranged such that its longitudinal axis is kept horizontal. The developing solution supply nozzle 525 may have a plurality of discharge ports on a lower surface so that the developing solution may discharge from the developing solution supply nozzle 525 as a sheet of fluid. The developing solution supply nozzle 525 may be detachably attached to a tip portion of a developing solution nozzle scan arm 528 through use of a holding member 528a. The developing solution nozzle scan arm 528 is attached to an upper end portion of a developing solution nozzle vertical support member 537 extending in a vertical direction from a top of a developing solution nozzle guide rail 529 arranged along the y-direction on base plate 514.
The developing solution supply nozzle 525 is configured to horizontally move along the y-direction by means of a y-axis drive mechanism 539 together with developing solution nozzle vertical support member 537.
The developing solution nozzle vertical support member 537 can be raised and lowered by a z-axis drive mechanism 540 so that the developing solution supply nozzle 525 is moved between a discharge position proximate substrate W and a non-discharge position there above by raising and lowering the developing solution nozzle vertical support member 537.
When dispensing the developing solution on substrate W, the developing solution supply nozzle 525 is positioned above substrate W, and substrate W is rotated one-half turn or more, e.g., one or more turns while the developing solution supply nozzle 525 is dispensing the developing solution. Note that at the time when the developing solution is dispensed, the developing solution supply nozzle 525 may be scanned along the developing solution nozzle guide rail 529 without rotating substrate W.
The rinse solution supply nozzle 526 may be detachably attached to a tip portion of a rinse solution nozzle scan arm 543. A rinse solution nozzle guide rail 544 is arranged outside the developing solution nozzle guide rail 529 on base plate 514. The rinse solution nozzle scan arm 543 is attached to an upper end portion of a rinse solution nozzle vertical support member 545 extending in the vertical direction from a top of the rinse solution nozzle guide rail 544 via a rinse solution nozzle x-axis drive mechanism 546.
The rinse solution supply nozzle 526 is configured to horizontally move along the y-direction by means of a y-axis drive mechanism 547 together with the rinse solution nozzle vertical support member 545. Furthermore, the rinse solution nozzle vertical support member 545 can be raised or lowered to move the rinse solution supply nozzle 526 between a discharge position proximate substrate W and a non-discharge position there above. Further, the rinse solution nozzle scan arm 543 is provided movable along the x-direction by means of the rinse solution nozzle x-axis drive mechanism 546.
The first chemical treatment solution supply nozzle 527A may be detachably attached to a tip portion of a first chemical treatment solution nozzle scan arm 549A. A first chemical treatment solution nozzle guide rail 550A is arranged outside the rinse solution nozzle guide rail 544 on base plate 514. The first chemical treatment solution nozzle scan arm 549A is attached to an upper end portion of a first chemical treatment solution nozzle vertical support member 551A extending in the vertical direction from a top of the first chemical treatment solution nozzle guide rail 550A via a first chemical treatment solution nozzle x-axis drive mechanism 552A.
The first chemical treatment solution supply nozzle 527A is configured to horizontally move along the y-direction by means of a first chemical treatment solution nozzle y-axis drive mechanism 553A together with the first chemical treatment solution nozzle vertical support member 551A. Furthermore, the first chemical treatment solution nozzle vertical support member 551A can be raised or lowered to move the first chemical treatment solution supply nozzle 527A between a discharge position proximate substrate W and a non-discharge position there above. Further, the first chemical treatment solution nozzle scan arm 549A is provided movable along the x-direction by means of the first chemical treatment solution nozzle x-axis drive mechanism 552A.
The second chemical treatment solution supply nozzle 527B may be detachably attached to a tip portion of a second chemical treatment nozzle solution scan arm 549B. A second chemical treatment solution nozzle guide rail 550B is arranged outside the rinse solution nozzle guide rail 544B on base plate 514. The second chemical treatment solution nozzle scan arm 549B is attached to an upper end portion of a second chemical treatment solution nozzle vertical support member 551B extending in the vertical direction from a top of the second chemical treatment solution nozzle guide rail 550B via a second chemical treatment solution nozzle x-axis drive mechanism 552B.
The second chemical treatment solution supply nozzle 527B is configured to horizontally move along the y-direction by means of a second chemical treatment solution nozzle y-axis drive mechanism 553B together with the second chemical treatment solution nozzle vertical support member 551B. Furthermore, the second chemical treatment solution nozzle vertical support member 551B can be raised or lowered to move the second chemical treatment solution supply nozzle 527B between a discharge position proximate substrate W and a non-discharge position there above. Further, the second chemical treatment solution nozzle scan arm 549B is provided movable along the x-direction by means of the second chemical treatment solution nozzle x-axis drive mechanism 552B.
It should be noted that the y-axis drive mechanisms 539, 547, 553A, and 553B, the z-axis drive mechanisms 540, 548, 554A, and 554B, the x-axis drive mechanisms 546, 552A, and 552B, and the rotary drive system 513 are controlled by a drive controller 555. The rinse solution supply nozzle 526, the first chemical treatment solution supply nozzle 527A, and the second chemical treatment solution supply nozzle 527B may move relative to each other in the x- and y-directions.
Further, as shown in
Although not shown, system 530 may further include a third chemical treatment solution supply nozzle for dispensing a third chemical solution onto substrate W, and a third chemical solution supply system for supplying the third chemical solution to the third chemical treatment solution supply nozzle.
Referring now to
Additionally, the rinse solution supply nozzle 526 is connected to a rinse solution supply system 655 storing the rinse solution via a rinse solution supply pipe 656. Along the rinse solution supply pipe 656, a rinse solution supply pump 657 is disposed, wherein a rinse solution supply valve 658 is located for supplying the rinse solution.
Furthermore, the first chemical treatment solution supply nozzle 527A is connected to a first chemical treatment solution supply system 662A storing the first chemical treatment solution via a first chemical treatment solution supply pipe 663A. Along the first chemical treatment solution supply pipe 663A, a first chemical treatment solution supply pump 664A is disposed, wherein a first chemical treatment solution supply valve 665A is located for supplying the first chemical treatment solution.
Further yet, the second chemical treatment solution supply nozzle 527B is connected to a second chemical treatment solution supply system 662B storing the second chemical treatment solution via a second chemical treatment solution supply pipe 663B. Along the second chemical treatment solution supply pipe 663B, a second chemical treatment solution supply pump 664B is disposed, wherein a second chemical treatment solution supply valve 665B is located for supplying the second chemical treatment solution.
The pumps 653, 657, 664A, and 664B and the valves 654, 658, 665A, and 665B are controlled by a supply control unit 600.
At least one process parameter for the first chemical treatment may be adjusted to improve the reduction of pattern collapse and/or pattern deformity. For example, the process parameter may include a rotation rate for the substrate, a dispensing rate for the first chemical solution, a concentration of a chemical constituent in the first chemical solution, etc.
Further, at least one process parameter for the second chemical treatment may be adjusted to improve the reduction of pattern collapse and/or pattern deformity. For example, the process parameter may include a rotation rate for the substrate, a dispensing rate for the second chemical solution, a concentration of a chemical constituent in the second chemical solution, etc.
Although only certain embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.
