Patent Application
20110143290
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2009-280047, filed on Dec. 10, 2009, the entire contents of which is incorporated herein by reference.
Embodiments described herein relate generally to a development treatment and a computer-readable storage medium for supplying a developing solution onto a substrate to develop an extreme ultra violet (EUV) resist film thereon.
In a semiconductor device manufacturing process using a photolithography technique, for example, a resist coating treatment of applying a resist solution onto a semiconductor wafer (hereinafter referred to simply as “wafer”) to form a resist film, an exposure processing of exposing a predetermined pattern on the resist film of the wafer, and a developing treatment of developing the exposed resist film on the wafer to form a resist pattern, are performed in order.
In recent years, chemically-amplified resists are in widespread use for the formation of the resist pattern. The chemically-amplified resists give a pattern through the phenomenon that acids are generated upon exposure and the acids in turn cause chemical reaction in the resist based on thermal diffusion activity, thereby causing a change in solubility of the radiation-exposed areas for a developing solution.
In the exposure processing described above, an exposure light source such as KrF laser (with a wavelength of 248 nm), ArF laser (with a wavelength of 193 nm), F2 laser (with a wavelength of 157 nm) or the like are employed to radiate light to the resist film on the wafer. In this case, in the subsequent developing treatment, a developing solution with a concentration of, for example, 2.38% by weight, is supplied onto the resist film formed on the wafer for the development of the resist film thereon (for example, see Japanese Laid-open Patent Publication No. 2005-221801). In the developing treatment, for example, the temperature of the developing solution is set to 23° C. and a time period of the developing treatment is set to 30˜60 seconds.
Incidentally, in recent years, to increase integration on semiconductor devices, a resist pattern formed on a wafer is being miniaturized. To do this, as the exposing light source to be used in the exposure processing, a light source which radiates an extreme ultra violet (EUV) with a wavelength in the range of, for example, 13˜14 nm is under consideration, which has a wavelength shorter than that of the KrF, ArF and F2 lasers.
Unfortunately, a EUV resist, which is used in EUV lithography and EUV-based exposure processing, is different than the resists used with the KrF, ArF or F2 lasers in terms of structure. Specifically, the EUV resist may have a low molecular weight relative to the KrF, ArF or F2 resists, which causes the EUV resist to easily undergo a chemical reaction based on developing solution activity. As such, the utilization of the related art technique described above, which supplies a developing solution onto a wafer whose EUV resist film undergoes development, results in a degraded line width roughness (LWR) of resist pattern. This fails to form a desired resist pattern onto the EUV resist film formed on the wafer.
The present disclosure has been developed in consideration of the above viewpoints and its object is to provide a method for properly forming a predetermined pattern onto an extreme ultra violet (EUV) resist film on a wafer W.
To attain the above object, according to one embodiment of the present disclosure, a developing treatment method is provided which supplies a developing solution onto a substrate to develop an extreme ultra violet (EUV) resist film thereon, wherein the temperature of the developing solution is set to fall within the range of 5° C. or higher to less than 23° C.
According to the research by the inventors of the present disclosure, it has been appreciated that when the temperature of the developing solution falls within the range of from 5° C. or higher to less than 23° C., a chemical reaction of the developing solution with the EUV resist film, particularly, permeation of the developing solution into the EUV resist film is inhibited. As a result, research has shown that the line width roughness (LWR) of the resist pattern formed on the EUV resist film is enhanced when compared to the prior art. Further, research has shown that development defects can be reduced when compared to the prior art. Therefore, according to the present disclosure, it is possible to properly form a predetermined resist pattern on the EUV resist film.
A time period during which the developing treatment is performed using the developing solution is in some embodiments set to fall within the range of 10 seconds or higher to less than 30 seconds.
The concentration of the developing solution is set in some embodiments to fall within the range of less than 2.38% by weight.
The method in some embodiments may further comprise, supplying a cleaning solution onto the substrate after supplying the developing solution onto the substrate, wherein a time period during which the cleaning solution is supplied is preferably set to fall within the range of 30 seconds or less.
According to another embodiment of the present disclosure, a program is provided which enables a computer to control a developing treatment apparatus for implementing said developing treatment method.
According to yet another embodiment of the present disclosure, provided is a computer-readable storage medium storing said program.
According to the present disclosure, it is possible to properly form a predetermined resist pattern on the EUV resist film.
Embodiments will now be described in detail with reference to the drawings.
As also shown in
In the cassette station 2, a plurality of cassettes C may be mounted on a cassette mounting stand 6 in one row in an X-direction (in a top-to-bottom direction in
The wafer carrier 8, which is rotatable in a O-direction around the Z-axis, can access a temperature regulating unit 60 and a transition unit 61 configured to deliver the wafers W, which will be described later, included in a third processing unit group G3 on the processing station 3.
The processing station 3 adjacent to the cassette station 2, may include, for example, five processing unit groups G1 to G5, in each of which a plurality of processing and treatment units are multi-tiered. On the side of the negative direction in the X-direction (in the downward direction in
As shown in
As shown in
In the fourth processing unit group G4, pre-baking units (PAB) 70 to 73 each for heat-processing the wafer W after the resist coating treatment, and post-baking units (POST) 74 to 77 each for heat-processing the wafer W after the developing treatment, are vertically stacked (eight-tiered) in order from the bottom.
In the fifth processing unit group G5, a plurality of thermal processing units each for performing thermal processing on the wafer W, for example high-precision temperature regulating units (CPL) 80 to 82, and post-exposure baking units (PEB) 83 to 87 each for heat-processing the wafer W after exposure, are vertically stacked (eight-tiered) in order from the bottom.
On the side of the positive direction in the X-direction of the first carrier unit A1 as shown in
As shown in
In the interface station 5, for example, a wafer carrier 101 moving on a carrier path 100 extending in the X-direction and a buffer cassette 102 are provided as shown in
Below, a detailed description will be directed to the configuration of the above-described developing treatment units (DEV) 30 to 34. As shown in
Disposed at the central portion in the treatment casing 110 is a spin chuck 120 for holding and rotating the wafer W. The spin chuck 120 may include a horizontal upper surface which is provided with, for example, a suction port (not shown) for sucking the wafer W. The suction from the suction port allows the wafer W to be sucked onto the spin chuck 120.
The spin chuck 120 may include, for example, a chuck driving mechanism 121 having a motor, which rotates the spin chuck 120 at a preset speed. The chuck driving mechanism 121 may be equipped with a lifting unit such as a cylinder for raising and lowering the spin chuck 120.
Around the spin chuck 120, a cup 122 is provided for receiving and collecting the liquid scattering or dropping from the wafer W. The cup 122 may include an opening at its top surface, which has a greater size than one of the wafers W to allow the spin chuck 120 to be elevated therethrough. The lower surface of the cup 122 is connected with a drain pipe 123 for draining the liquid collected in the cup 122 therethrough externally, and an exhaust pipe 124 for exhausting ambient gas in the cup 122 therethrough externally.
As shown in
As shown in
As shown in
To the second arm 132, a pure water supply nozzle 140 for supplying pure water as a cleaning solution is supported. The second arm 132 is movable on the rail 130 by means of a nozzle driving unit 141 as shown in
A supply pipe 144 is connected to the pure water supply nozzle 140. As shown in
The developing treatment units (DEV) 31 to 34 has the same configuration as that of the developing treatment unit (DEV) 30, so a description thereof will be omitted to avoid duplication.
In the coating and developing treatment system 1 described earlier, a control unit 200 is provided as shown in
The coating and developing treatment system 1 of the illustrative embodiment may be configured as above. Subsequently, a description will be made as to a series of processes which are performed on the wafer W in the coating and developing treatment system 1.
Initially, when a cassette C in which a plurality of unprocessed wafers W are housed is mounted on the cassette mounting stand 6, the unprocessed wafers W are picked-up individually by the wafer carrier 8, and carried to the temperature regulating unit (TCP) 60 in the third processing unit group G3. The wafer W carried to the temperature regulating unit (TCP) 60 is temperature-regulated to a predetermined temperature. Next, the wafer W is carried by the first carrier unit A1 into a bottom coating unit (BARC) 23 where an anti-reflection film is formed on the wafer W. The wafer W on which the antireflection film has been formed is sequentially carried by the first carrier unit A1 to the heating unit (HP) 92, the high-precision temperature regulating unit (CPL) 62 and the hydrophobic processing unit (AD) 90 so that the wafer W is subjected to predetermined processing and treatment in each of the units. Thereafter, the wafer W is carried to the resist coating unit (COT) 20 by the first carrier unit A1 where a resist solution for EUV is applied onto the surface of the wafer W to form a resist film on the wafer W.
After that, the wafer W on which the resist film for EUV has been formed is carried by the first carrier unit A1 to the pre-baking unit (PAB) 70 where wafer W is subjected to a pre-baking treatment. Subsequently, the wafer W for which the pre-baking treatment has been finished is carried by the second carrier unit A2 to the edge exposure unit (WEE) 94 and the high-precision temperature regulating unit (CPL) 82 in sequence so that the wafer W is subjected to predetermined processing and treatment in each of the units. Thereafter, the wafer W is carried by the wafer carrier 101 in the interface station 5 to the exposing unit 4. In the exposing unit 4, a EUV light is radiated onto the EUV resist film formed on the wafer W so that a predetermined pattern is selectively exposed on the EUV resist film.
After that, the wafer W for which exposure processing has been finished is carried by the wafer carrier 101 to the post-exposure baking unit (PEB) 83 to undergo a post-exposure baking treatment. And then, the wafer W for which post-baking treatment has been finished is carried by the second carrier unit A2 to the high-precision temperature regulating unit (CPL) 81 where the wafer W is subjected to a temperature regulating treatment.
Subsequently, the wafer W is carried by the second carrier unit A2 to the developing treatment unit (DEV) 30. In the developing treatment unit (DEV) 30, the wafer W is mounted and held on the spin chuck 120. Then, the developing solution supply nozzle 133 at the waiting section 135 moves to the outer periphery of the wafer W by means of the first arm 131.
Subsequently, controlling the chuck driving mechanism 121 allows the spin chuck 120 to rotate the wafer W at a predetermined rotation speed. And then, the developing solution supply nozzle 133 supplies the outer periphery of the wafer W with a developing solution having a concentration of, for example, below 2.38% by weight. In such a case, the temperature of the developing solution discharged from the developing solution supply nozzle 133 is adjusted in a temperature range from 5° C. or higher to less than 23° C. by the temperature adjustment unit of the supplying equipment set 138. After that, the developing solution supply nozzle 133, while moving toward the central portion of the wafer W, discharges the developing solution to the EUV resist film formed on the wafer W. This allows the developing solution discharged from the developing solution supply nozzle 133 to be spirally supplied onto the wafer W. The developing solution is uniformly spread over the entire surface of the wafer W while being coated on the entire surface of the wafer W. This enables the EUV resist film formed on the wafer W to undergo development so that the exposed area in the EUV resist film is dissolved to form a resist pattern on the wafer W. In the wafer developing treatment of the illustrative embodiment, a developing treatment time at which the developing solution supply nozzle 133 supplies the developing solution onto the surface of the wafer W, may fall within the range from 10 seconds or higher to less than 30 seconds.
Upon completion of the developing treatment on the wafer W, the first arm 131 enables the developing solution supply nozzle 133 to move from a position above the central portion of the wafer W to the waiting section 135. Simultaneously, the second arm 132 enables the pure water supply nozzle 140 at the waiting section 142 to move to a position above the central portion of the wafer W. After that, while the wafer W is being rotated, the pure water supply nozzle 140 supplies pure water to the central portion of the wafer W so that wafer W is subjected to a cleaning treatment. In the cleaning treatment of the illustrative embodiment, a pure water supply time at which the pure water supply nozzle 140 supplies the pure water to the wafer W may fall within the range of 30 seconds or below.
Subsequently, the supplement of the pure water from the pure water supply nozzle 140 to the wafer W is terminated and simultaneously the rotation of the wafer W is accelerated so that the pure water remaining on the wafer W is washed away for drying. Thus, a series of developing treatment is completed.
When the EUV resist film on the wafer W is developed in the developing treatment unit (DEV) 30, the wafer W is carried by the second carrier unit A2 to the post-baking unit (POST) 74 where the post-baking treatment is performed, and then carried by the first carrier unit A1 to the high-precision temperature regulating unit (CPL) 63 where the wafer W is subjected to temperature regulation. And then, the wafer W is carried by the first carrier unit A1 to the transition unit (TRS) 61 and then returned to the cassette C by the wafer carrier 8. Thus, a series of photolithography treatments are terminated.
According to the illustrative embodiment, in the development treatment performed in the developing treatment unit (DEV) 30, the temperature of the developing solution to be supplied on the EUV resist film falls within the range from 5° C. or higher to less than 23° C., thereby rendering it possible to inhibit a chemical reaction of the developing solution with the EUV resist film, especially, permeation of the developing solution into the EUV resist film. This enhances the LWR of the resist pattern formed on the EUV resist film, thereby enabling a predetermined resist pattern to be properly formed on the EUV resist film.
Herein, a description will be made as to an effect that the LWR of the resist pattern formed on the EUV resist film can be improved when the temperature of the developing solution is set to fall within the range of 5° C. or higher to less than 23° C. The inventors of the present disclosure have experimentally verified the effect under a condition that the temperature of the developing solution is varied within the range of 5° C. to 40° C. for measurement of the LWR of the resist pattern. In the experiment, in addition to the LWR of the resist pattern, a resist sensitivity (E size) of the EUV resist film was further measured.
Referring to
This experiment was also performed on the exposure latitude (EL). The exposure latitude represents the influence of a line width of the resist pattern on a dose amount used in exposure processing. Specifically, if the exposure latitude becomes greater, the deviation of the line width of the resist pattern from a target dimension becomes smaller even with a varied dose amount, resulting in enhanced performance of photolithography.
Referring to
According to the illustrative embodiment above, the developing treatment time at which the developing solution is supplied to the EUV resist film on the wafer W is set to fall within the range greater than or equal to 10 seconds to less than 30 seconds, thereby rendering it possible to further inhibit a chemical reaction of the developing solution with the EUV resist film. This further enhances the LWR of the resist pattern formed on the EUV resist film.
Herein, a description will be made as to the effect the LWR of the resist pattern on the EUV resist film is improved when the developing treatment time is set to fall within the range of 10 seconds or larger to less than 30 seconds. The inventors of the present disclosure have experimentally verified the effect under a condition that the developing treatment time is varied within the range of 10 seconds to 90 seconds for measurement of the LWR of the resist pattern. In the experiment, in addition to the LWR of the resist pattern, a resist sensitivity (E size) of the EUV resist film was further measured.
Referring to
This experiment was also performed on the exposure latitude (EL).
According to the illustrative embodiment above, the concentration of the developing solution to be supplied onto the EUV resist film on the wafer W is set to be less than 2.38% by weight, thereby rendering it possible to further inhibit a chemical reaction of the developing solution with the EUV resist film. This further enhances the LWR of the resist pattern on the EUV resist film.
Herein, a description will be made as to the effect the LWR of the resist pattern formed on the EUV resist film is improved when the concentration of the developing solution is set to be less than 2.38% by weight. The inventors of the present disclosure have experimentally verified the effect under a condition that the concentration of the developing solution is varied within the range of 1% to 3.5% by weight for measurement of the LWR of the resist pattern. In the experiment, in addition to the LWR of the resist pattern, a resist sensitivity of the EUV resist film was further measured.
Referring to
This experiment was also performed on the exposure latitude.
According to the illustrative embodiment above, in the wafer cleaning treatment performed in the developing treatment unit (DEV) 30, the pure water supply time at which the pure water supply nozzle 140 supplies the pure water onto the wafer W falls within the range of less than 30 seconds. According to the research by the inventors of the present disclosure, it has been appreciated that a prolonged pure water supply time results in a swollen EUV resist film, thereby rendering the EUV resist film thick. On the other hand, it has been appreciated that a short period of pure water supply time, preferably less than 30 seconds, inhibits the EUV resist film from being swollen, thereby making it possible to form the resist pattern in a desired shape.
Herein, a description will be made as to the effect that the swelling of the EUV resist film is inhibited for a short period of pure water supply time, preferably less than 30 seconds. The inventors of the present disclosure have experimentally verified the effect under a condition that the dose amount to be used in the exposing process is varied at 15, 30 and 60 seconds of the pure water supply times. In such a case, the developing treatment time was set to 30 seconds.
Referring to
It can be also appreciated that, in a small range of dose amount, the amount of film decrease of the EUV resist film is so small as to result in a slight variation in film thickness of the EUV resist film before and after the developing treatment. This enables the formation of a pertinent thickness of the EUV resist film.
A description will be made as to the effect that development defects of the EUV resist film can be reduced. The development defects may include pattern collapse after developing treatment, precipitation-based defects, residue defects or the like. The inventors of the present disclosure have experimentally verified the effect under a condition that the temperature of the developing solution is varied within the range of 5° C. to 40° C. for measurement of the development defects.
Referring to
In the illustrative embodiment above, the developing solution temperature has been explained to be in the range of 5° C. or higher to less than 23° C. However, in other embodiments, the developing solution temperature may be in the range of 23° C. or higher to 40° C. or below. In such a case, as shown in
Similarly, while the developing treatment time has been explained to be in the range of 10 seconds or higher to less than 30 seconds in the illustrative embodiment above, the developing treatment time may be 30 seconds. Further, while the concentration of the developing solution has been explained to be in the range of less than 2.38% by weight in the illustrative embodiment above, the concentration of the developing solution may be in the range of 2.38% or higher to 3.0% or less by weight.
While the temperature regulating unit of adjusting the temperature of the developing solution has been explained to be disposed inside the supplying equipment set 138 in the illustrative embodiment above, the temperature regulating unit may be disposed in the vicinity of the developing solution supply nozzle 133. This allows the temperature of the developing solution to be adaptively and firmly adjusted to a predetermined temperature.
While the developing solution having a predetermined temperature has been explained to be retained inside the developing solution supply source 136 in the illustrative embodiment above, a temperature regulating unit of adjusting the temperature of the developing solution may be disposed in the developing solution supply source 136. This allows the concentration of the developing solution to be adaptively adjusted to a predetermined concentration.
Further, in the illustrative embodiment above, the developing solution supply nozzle 133 has been explained to supply the developing solution onto the EUV resist film formed on the wafer W while moving from the outer periphery of the wafer W to its central portion. However, in other embodiments, the developing solution supply nozzle 133 may supply the developing solution onto the central portion of the wafer W. Under such a configuration, a centrifugal force involved in the rotation of the wafer W allows the developing solution supplied onto the central portion of the wafer W to be spread onto the wafer W.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and mediums described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications which would fall within the scope and spirit of the inventions. The technical features of the illustrative embodiment are also applicable treating substrates other than the wafer, such as a flat panel display (FPD) and a mask reticule for a photo mask.
The present disclosure is useful in supplying a developing solution onto a substrate such as a semiconductor wafer to develop an EUV resist film formed on the substrate.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-280047 | Dec 2009 | JP | national |
