This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-185725, filed on Sep. 11, 2014; the entire contents of which are incorporated herein by reference.
An embodiment of the present invention relates to a photosensitive composition, an imprint method, and an interlayer layer.
In recent years, an imprint method is attracting attention as one of processes used for forming a semiconductor device. In the imprint method, a template, or an original plate mold, is used. On the template, a template pattern to be transferred to a substrate such as a wafer is formed. Then, during imprint processing, a photocurable organic material (resist) is made into a droplet and is dropped on the substrate by an inkjet. Then, the template is brought into contact with the droplet of the resist, whereby the resist is pushed and enlarged.
Moreover, in a state where the template is in contact with the resist, the resist is irradiated with light. Accordingly, the resist is hardened, and the template is released from the hardened resist, whereby a resist pattern is formed on the substrate.
According to an embodiment, a photosensitive composition is provided. The photosensitive composition contains a photosensitive material. In the photosensitive composition, when a whole amount of the composition is 100 pts. mass, a sum total of values each obtained by multiplying a SF value, which is a solubility parameter, by a mass percentage of a photopolymerizable monomer contained in the composition is any value within a range of 17 to 20 [(J/cm3)1/2].
Hereinafter, a photosensitive composition, an imprint method, and an interlayer layer according to an embodiment are described in detail with reference to the attached drawings. Note that the present invention is not to be limited by the embodiment.
The imprint device 1 of the embodiment executes imprint processing using a resist (for example, a photosensitive composition such as a photocurable organic material) containing, as a main component, a material capable of dissolving a molecular contaminant. The imprint device 1 also forms an adhesion layer containing, as a main component, a material capable of dissolving the molecular contaminant in a lower layer of the resist.
The imprint device 1 is provided with an original plate stage 2, a controller 3, a substrate chuck 4, a sample stage 5, a reference mark 6, an alignment sensor 7, an UV light source 8, a stage base 9, a liquid dropping device 25, and a coating device 26.
The wafer Wa is placed on the sample stage 5, and the sample stage 5 moves within a plane surface (horizontal surface) parallel to the wafer Wa placed thereon. The sample stage 5, when an adherence agent is applied to the wafer Wa, moves the wafer Wa underneath the coating device 26. The sample stage 5, when the resist is dropped as a transfer material on the wafer Wa, moves the wafer Wa underneath the liquid dropping device 25. The sample stage 5, when impression processing is performed on the wafer Wa, moves the wafer Wa underneath the template 20.
On the sample stage 5, there is provided the substrate chuck 4. The substrate chuck 4 fixes the wafer Wa at a predetermined position on the sample stage 5. On the sample stage 5, there is also provided the reference mark 6. The reference mark 6 is a mark for detecting a position of the sample stage 5, and it is used for alignment when the wafer Wa is loaded on the sample stage 5.
The original plate stage 2 is provided on a side of the wafer Wa, or a bottom face side of the stage base 9. The original plate stage 2 fixes the template 20 to a predetermined position from a back surface side (a side of a surface on which the template pattern is not formed) of the template 20 by vacuum suction or the like.
The stage base 9 supports the template 20 by the original plate stage 2 as well as presses the template pattern of the template 20 against the resist on the wafer Wa. The stage base 9 performs pressing of the template 20 against the resist and releasing of the template 20 from the resist by moving in a vertical direction. The alignment sensor 7 is provided on the stage base 9. The alignment sensor 7 is a sensor that performs position detection of the wafer Wa and position detection of the template 20.
The liquid dropping device 25 is a device that drops the resist on the wafer Wa by an inkjet method. The liquid dropping device 25 is provided with an inkjet head (not illustrated) having a plurality of micropores that jets a droplet of the resist.
The coating device 26 is a device that applies the adherence agent to the wafer Wa by a method such as a spin coat method. By applying the adherence agent to the wafer Wa, an interlayer layer such as an adhesion layer 11 described below is formed on the wafer Wa. The adhesion layer 11, which is a layer between the resist and the wafer Wa, allows the resist to adhere to the wafer Wa. In other words, the adhesion layer 11 is a layer that enhances adhesion between the resist and the wafer Wa. Both of the adhesion layer 11 and the resist are imprint materials.
The coating device 26 applies the adherence agent to the wafer Wa before the resist is dropped on the wafer Wa. Accordingly, the coating device 26 forms, for example, the adhesion layer 11 having thickness of 5 nm on the wafer Wa.
The UV light source 8 is a light source that is provided above the stage base 9 and radiates UV light. In a state where the template 20 is pressed against the resist, the UV light source 8 radiates the UV light from above the template 20. Note that the light (visible light or invisible light) radiated on the template 20 is not limited to the UV light and may be light of any wavelength.
The controller 3 is connected to each of constituent elements of the imprint device 1 and controls each of the constituent elements.
When imprinting is performed on the wafer Wa, the wafer Wa placed on the sample stage 5 is moved directly underneath the coating device 26. Then, the adherence agent is applied to the wafer Wa. Subsequently, the wafer Wa placed on the sample stage 5 is moved directly underneath the liquid dropping device 25. Then, the resist is dropped at a predetermined shot position on the adhesion layer 11 of the wafer Wa.
The resist to be dropped on the wafer Wa contains, as a main component, a material capable of dissolving the molecular contaminant. For example, as the main component of the resist, a material is used with which a difference between a solubility parameter (SP) value of the main component of the resist and a SP value of the molecular contaminant to be dissolved is within a first predetermined range (for example, 1.67 to 2.21).
Similarly, the adhesion layer 11 (adherence agent) contains, as a main component, a material capable of dissolving the molecular contaminant. For example, as the main component of the adhesion layer 11, a material is used with which a difference between a SP value of the main component of the adhesion layer 11 and the SP value of the molecular contaminant to be dissolved is within a second predetermined range (for example, 1.67 to 2.21) is used.
The SP value is a parameter indicating solubility. For example, solubility of a first material in a second material is determined by a difference between a SP value of the first material and a SP value of the second material. Therefore, in the embodiment, the resist composed of a main component having a SP value corresponding to that of the molecular contaminant is used. Also, the adhesion layer 11 composed of a main component having a SP value corresponding to the molecular contaminant is used.
In the resist of the embodiment, when a whole amount of a composition is 100 pts. mass, a sum total of values each obtained by multiplying a SP value by a mass percentage of a photopolymerizable monomer contained in the composition is any value within a range of 17 to 20 ((J/cm3)1/2. For the adhesion layer 11 of the embodiment, when a whole amount of a contained component is 100 pts. mass, a sum total of values each obtained by multiplying a SP value, which is a solubility parameter, by a mass percentage of each component contained in the contained component is any value within a range of 17 to 21 [(J/cm3)1/2].
When the resist is dropped, in the coating device 26 in a previous process, during conveyance in a clean room, and the like, the molecular contaminant may adhere to an upper surface side of the wafer Wa. The molecular contaminant exists on the wafer Wa in a state of being sucked by energy of a weak van der Waals force. Therefore, the SP value of the main component of the resist is set, for example, based on the SP value of the molecular contaminant existing on the upper surface side of the wafer Wa when the resist is dropped. The main component of the resist is a substance capable of dissolving the molecular contaminant by the time the resist is filled in the template pattern.
The SP value of the main component of the adhesion layer 11 is set, for example, based on the SP value of the molecular contaminant existing on the upper surface side of the wafer Wa when the resist is dropped or when the adhesion layer 11 is applied. The main component of the adhesion layer 11 is the substance capable of dissolving the molecular contaminant by the time the resist is filled in the template pattern.
Note that the molecular contaminant may be dissolved in the resist or the adhesion layer 11 at any timing as long as a resist pattern does not become a pattern failure.
After the resist has been dropped on the wafer Wa, the wafer Wa on the sample stage 5 is moved directly underneath the template 20. Then, the template 20 is pressed against the resist on the wafer Wa.
After the template 20 has been brought into contact with the resist for a predetermined time, in this state, the UV light source 8 irradiates the resist and hardens it, whereby a transfer pattern corresponding to the template pattern is patterned on the resist on the wafer Wa. Subsequently, the imprint processing is performed on a next shot.
Next, processing procedure of an imprint process is described.
As illustrated in
Also in the clean room, it has been known that there exists, as the molecular contaminant 12, for example, an acid gas such as SOx, NOx, HCl, Cl2, and HF, a basic gas such as NH3 and amine, an organic substance such as siloxane and dioctyl phthalate (DOP), and a dopant such as boron and phosphorus used for manufacturing of a semiconductor device.
The above-described molecular contaminant 12 may adhere to the wafer Wa. In the embodiment, the adhesion layer 11 is formed on the wafer Wa by the coating device 26 by the spin coat method. Then, a difference between the SP value of the main component of the adherence agent and the SP value of the molecular contaminant 12 to be dissolved is within the second predetermined range. Therefore, the adhesion layer 11 dissolves the molecular contaminant 12 on the wafer Wa. As a result, the molecular contaminant 12 on the wafer Wa is removed.
After the adhesion layer 11 has been formed on the wafer Wa, as illustrated in
The molecular contaminant 12 may adhere to a surface of the adhesion layer 11 and to a surface of the resist 33 between forming processing of the adhesion layer 11 and pressing processing of the template 20 against the resist 13. In the embodiment, the liquid dropping device 25 drops the resist 13 on the wafer Wa. Then, a difference between a SP value of the main component of the resist 13 and the SP value of the molecular contaminant 12 to be dissolved is within the first predetermined range. Therefore, the resist 13 dissolves the molecular contaminant 12 on the wafer Wa. As a result, the molecular contaminant 12 on the wafer Wa is removed.
When the template 20, which is formed by engraving a quartz substrate or the like, is pressed against the resist 13, the resist 13 flows into the template pattern of the template 20 by a capillary phenomenon. After the template 20 has been pressed against the resist 13, the resist 13 is filled in the template pattern for a preset time.
Subsequently, the UV light is radiated from above the template 20. Accordingly, the resist 13 is hardened. Then, the template 20 is released from the hardened resist 13. Accordingly, as illustrated in
Here, the SP value of the molecular contaminant 12 is described.
The main component of the resist 13 may be, for example, ethylacrylate having the SP value of 18.29 [(J/cm3)1/2]. Note that the SF value of the main component of the resist 13 is determined according to a type of the molecular contaminant 12 to be dissolved. For example, to dissolve the molecular contaminant 12 illustrated in
Similarly, the SP value of the main component of the adhesion layer 11 is determined according to the type of the molecular contaminant 12 to be dissolved. For example, to dissolve the molecular contaminant 12 illustrated in
Next, a configuration of the resist 13 is described.
In the resist 13A illustrated in
In the resist 13B illustrated in
Note that the reactive group 30 bonded in the resist 13A or the resist 13B may also be a methacryloyl group.
The acryloyl group 31 or the methacryloyl group 32 is bonded to a terminal or a side chain of a molecule of the main component contained in the resist 13. Note that the adhesion layer 11, similar to the resist 13, has at least one or more types of the reactive group 30 and an organic group and structure thereof is similar to that of the resist 13, whereby a description thereof is omitted.
Each of the compositions A to E contains a plurality of monomers and another component (polymerization initiator and release agent). For example, the composition A contains 1,6-hexanediol diacrylate and stearyl acrylate as the monomers. The 1,6-hexanediol diacrylate and the stearyl acrylate constitute 77.6 wt % and 18.4 wt %, respectively. The SP value of the 1,6-hexanediol diacrylate is 20.52 and the SP value of the stearyl acrylate is 18.17. The SP value of the composition A is 20.07.
The composition B contains 1,10-Decanediol (47.5 wt %, SP value: 19.87) and the stearyl acrylate (48.5 wt %) as the monomers. The SP value of the composition B is 19.00.
The composition C contains dendritic acrylate (4.85 wt %, SP value: 24.0) and the stearyl acrylate (91.15%) as the monomers. The SP value of the composition C is 18.46.
The composition D contains trimethylolpropane triacrylate (4.85 wt %, SP value: 20.5) and the stearyl acrylate (91.15 wt %) as the monomers. The SP value of the composition D is 18.29.
The composition E contains perfluorooctylethyl acrylate (64 wt %, SP value: 15.5) and the 1,6-hexanediol diacrylate (34 wt %) as the monomers. The SP value of the composition E is 17.21.
For example, the SP value of the composition A is calculated by using the following formula:
Since the compositions A to E have a property as illustrated in
As illustrated in
After the adhesion layer 51 has been formed on the wafer 50, as illustrated in
Subsequently, as illustrated in
After the template 20 has been pressed against the resist 53, the resist 53 is filled in the template pattern for a preset time. Subsequently, the resist 53 is hardened by the UV light being radiated from above the template 20. Then, the template 20 is released from the hardened resist 53.
Accordingly, as illustrated in
On the other hand, in the embodiment, the imprint processing is executed by using the resist 13 containing, as the main component, a substance with which a difference in the SP value with the molecular contaminant 12 is smaller than before. For example, when the SP value of a major molecular contaminant is 17 to 18 [(J/cm3)1/2], the SP value of the resist 53 and the like is about 22 to 25 [(J/cm3)1/2]. On the other hand, the SP value of the resist 13 used in the embodiment is 17 to 18 [(J/cm3)1/2], which is equivalent to the SP value of the major molecular contaminant. Therefore, it is possible to prevent occurrence of a pattern failure caused by the molecular contaminant 12. As a result, it is possible to suppress a decrease in a yield of the semiconductor device manufactured by using the imprint processing.
The imprint processing by the imprint device 1 is performed, for example, for each layer in a wafer process. Then, the semiconductor device (semiconductor integrated circuit) is manufactured by the wafer process being repeated for each of the layers.
Specifically, after the template 20 has been manufactured, the imprint device 1 forms the adhesion layer 11 on the wafer Wa and subsequently drops the resist 13 on the wafer Wa. Subsequently, the imprint device 1 presses the template 20 against the resist 13 and forms the resist pattern using the resist 13. Then, using the resist pattern as a mask, etching is performed on a lower layer side of the wafer Wa. Accordingly, an actual pattern corresponding to the resist pattern is formed on the wafer Wa. When the semiconductor device is manufactured, the imprint processing, etching processing, and the like using the above-described adhesion layer 11 and the resist 13 are repeated for each of the layers.
Note that in the embodiment, a case in which the imprint processing is executed by using the adhesion layer 11 has been described; however, the imprint processing may also be executed without using the adhesion layer 11. Also, the SP value of the adhesion layer 11 may be an arbitrary value.
The resist 13 may be applied to the wafer Wa by the spin coat method and the like. The adherence agent may be dropped on a wafer by the inkjet method.
Before the adherence agent is applied, cleaning processing of the wafer Wa may be executed. Before the adherence agent is applied or the resist 13 is dropped, cleaning processing of the imprint device 1 may also be executed.
It is also possible to set a SP value corresponding to the molecular contaminant 12 that is not removable in the cleaning processing to the adherence agent or the resist 13. In this case, for example, the molecular contaminant 12 having a first SP value is removed in the cleaning processing, and the molecular contaminant 12 having a second SP value is removed in the adhesion layer 11 or the resist 13.
Also, an interlayer layer such as the above-described adhesion layer 11 may be any member as long as it is a layer (member) disposed between the resist 13 and the wafer Wa. The interlayer layer such as the adhesion layer 11, for example, may contain propylene glycol monoethyl ether acetate (1-methoxy-2-propanol acetate)(SP value is 18.8 [(J/cm3)1/2]) as the main component.
In this way, in the embodiment, the SP value of the main component of the resist 13, which is the imprint material, is any value within the range of 17 to 21. Therefore, even in a case where the molecular contaminant 12 exists in a process atmosphere during the imprint processing, it is possible to dissolve the molecular contaminant 12 in the resist 13. Accordingly, it is possible to suppress the condensation and segregation of the molecular contaminant 12, whereby it is possible to decrease the pattern failure caused by the molecular contaminant 12.
Since the SP value of the main component of the adhesion layer 11 is any value within the range of 17 to 21 [(J/cm3)1/2], it is possible to dissolve the molecular contaminant 12 in the adhesion layer 11. Since the SP value of the main component of the resist 13 is any value within the range of 17 to 20 [(J/cm3)1/2], even in a case where the resist 13 is dropped by the inkjet method, it is possible to dissolve the molecular contaminant 12 in the resist 13.
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 embodiments 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 as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2014-185725 | Sep 2014 | JP | national |