This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-039325, filed Feb. 24, 2012; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a pattern formation apparatus, a pattern formation method and a method for producing semiconductor devices.
In the pattern formation methods, the imprint method, which uses a master plate (template) having an embossed pattern having protrusions and recesses that is transferred to an object has been used. In the imprint method, a photo-curable organic material, as an example, is coated on the substrate and cured by light irradiation in contact with the template of the organic material layer. This forms an embossed pattern by transferring a reverse image of the three-dimensional protrusions and recesses embossed pattern of the template onto the organic material layer.
It is important, in the pattern formation methods using a template, to form patterns in consideration of slippage of the embossed pattern of the template during embossing of a film with the pattern.
In general, one embodiment will be explained based on the drawings.
Furthermore, the drawings are schematic or conceptual, and the relation between thickness and width at each part and size ratio between parts are not necessarily equal to that in practice. Further, even in the case of showing the same place, sometimes the mutual dimension or ratio is expressed differently.
Furthermore, the same number is used for the same element as that in each drawing of the detailed description to avoid having to re-state a detailed explanation.
According to the embodiment, there is provided a pattern formation apparatus for carrying out pattern formation under consideration of position slippage due to unevenness pattern of the template, a pattern formation method and a method for producing semiconductor devices.
The pattern formation apparatus relating to the embodiment is a pattern formation apparatus wherein an object, such as a substrate having a pattern transferring thereon, is to be patterned according to an embossed pattern formed on a surface of a template. The object is irradiated with light under the state of affixing the embossed pattern of the template to the object to cure the pattern transferring, in order to transfer the embossed pattern to the object.
The pattern formation apparatus provides a light irradiation part and a control part.
The light irradiation part irradiates light having a variable intensity distribution in an irradiation plane that is substantially parallel to the plane of the surface of the template.
The control part controls the light irradiation part to change the intensity distribution according to time.
As expressed in
Here, the template 110 has a base material 10 and the embossed pattern 21 is formed on a main plane 10a of the base material 10. The embossed pattern 21 of the template 110 is formed by using a master, or using photolithographic and etching techniques, for example. As the base material 10, for example, quartz is used. For the embossed protrusion and recess pattern 21, for example, a photo-curable organic material is used. In the case of forming a template 110 from the master, a photo-curable organic material is coated on the base material and the pattern of protrusions and recesses of the master is transferred to the photo-curable organic material as a negative three dimensional pattern of the template. The photo-curable organic material is cured to create therein the embossed pattern 21 as a negative, or inverse pattern, to the pattern of recesses and protrusions of the template 110 while to template is engaged with the photo-curable organic material.
The pattern formation apparatus 200 is provided with a light irradiation part 210 and a control part 220.
The light irradiation part 210 irradiates light C having an intensity distribution within an irradiation plane R that is substantially parallel to the main plane 10a of the base material 10 of the template 110. Here, the irradiation plane R is a plane in parallel to the main plane 10a in the region of the pattern transferring material 70 being irradiated with the light C. Further, an intensity of light indicates an energy density of light. The light irradiation part 210 provides a mechanism capable of changing the intensity distribution of light C in the irradiation plane R.
The control part 220 controls the light irradiation part 210 to change the intensity distribution of light C within the irradiation plane R according to time.
In the pattern formation apparatus 200 relating to this embodiment, the intensity distribution of light C in the irradiation plane R is changed with time to control distortion caused during curing of the pattern transferring material 70 by light C. Namely, the intensity distribution of light C in the irradiation plane R is changed by time so that the balance of shrinkage distortion caused during curing by light C of the pattern transferring material 70 in the irradiation plane R is controlled. This adjusts the position of the pattern being formed by curing the pattern transferring material 70 in the irradiation plane R. Thus, even when there is a position slippage with respect to a standard (a foundation pattern, an alignment mark or other position indicator) in the embossed pattern 21 of the template 110, the influence of the slippage on the pattern being formed on the pattern transferring material 70 is prevented.
An input part 230 may be installed in the pattern formation apparatus 200. The input part 230 is a part for inputting data D showing the change of the intensity distribution of light C in the irradiation plane R with time. The input part 230 includes an input interface of the nonvolatile memory and interface with a network, for example, various input devices such as a keyboard, pointing device, etc. Namely, the data D are input by the input device from a nonvolatile memory or external devices (computer, database, etc.) through the network.
Here, the data D include the relation between the slippage amount and direction with respect to the standard of embossed pattern 21 of the template 110, as well as the change of intensity distribution of light C in the irradiation plane R with time. The standard of the embossed pattern 21 includes the design value of the embossed pattern 21, position of the pattern transferred to the pattern transferring material relative to the foundation pattern, the position of an element, such as an alignment mark, formed on a substrate, etc.
The pattern formation apparatus 200 provides a retaining part 240 for retaining the template 110 and a stage 250 for holding the substrate 60. The retaining part 240 is adsorption-retained, for example, at the side opposite to the embossed pattern 21 of the base material 10 of the template 110.
The stage 250 is fixed at the position at which the substrate 60 is located. The pattern transferring material 70 is placed on the substrate 60.
The control part 220 controls the distance between the retaining part 240 and the stage 250. Namely, a moving mechanism (not shown) is provided at the retaining part 240 and/or the stage 250 to move the retaining part 240 and/or the stage 250 toward the other. The control part 220 controls the moving mechanism to control the distance between the retaining part 240 and the stage 250. In this way, contact of the embossed pattern 21 of the template 110 to the pattern transferring material 70 and releasing of the template 110 from the pattern transferring material 70 are carried out.
The light irradiation part 210, retaining part 24 and stage 250 in the constitution of the pattern formation apparatus 200 are shown in
The light irradiation part 210 includes a dividing part 211 and a regulation part 215. The dividing part 211 may be a beam splitter that divides the irradiation of light C into plural regions in the irradiation plane R in parallel to the main plane 10a. In the dividing part 211, plural optical fibers, as an example, are used. In this case, the dividing part 211 branches the light released from the light source 217 by plural optical fibers to irradiate it onto plural regions in the irradiation plane R. As the light source 217, for instance, a high-pressure mercury lamp is used. The light to be released from the light source 217 consists of ultraviolet rays of, for instance, about 310 nanometers (nm).
Plural reflex mirrors may be used in the dividing part 211. In this case, the light released from the light source 217 is irradiated onto plural regions in the irradiation plane R, respectively, by the plural reflex mirrors.
The regulation part 215 regulates the intensity of light C in plural regions divided by the dividing part 211 according to the intensity distribution. In the regulation part 215, liquid crystal element, as an example, is used. When optical fibers are used as the dividing part 211, liquid crystal elements are installed in plural optical fibers, respectively. The regulation part 215 regulates the light transmittance of each liquid crystal element. In this way, the intensity of light C irradiated to plural regions respectively from each optical fiber in the irradiation region R is regulated. The regulation part 215 regulates the intensity of light C in plural regions in the irradiation plane R according to the intensity distribution in accordance with the instruction from the control part 220.
The function of the dividing part 211 and the regulation part 215 may be different from each other. As the dividing part 211, for example, independent plural light sources 217 may be used for each of the plural regions. In this case, the regulation part 215 regulates the intensity of radiation of independent plural light source 217 to regulate the intensity of light C being irradiated to each of plural regions in the irradiation plane R.
As shown in
The regulation part 215 shown in
In this way, when the intensity of light C on plural regions r1, r2, . . . rn-1, and rn in the irradiation plane R is regulated by the light irradiation part 210, the intensity distribution of light C in the irradiation plane R can be set up as shown in
When the irradiation plane R is divided into, for example, the region RL (left side) and the region RR (right side) in the example of intensity distribution as shown in
The light irradiation part 210 regulates the intensity of light C in the irradiation plane R in plural regions r1, r2, . . . rn-1, and rn to give the intensity distribution as shown in, for example,
In
In the example shown in
In
If the intensity distribution of light C is changed with time, the amount of shrinkage that occurs during curing of the pattern transferring material 70 is changed. Shrinkage induces stress in the pattern transferring material that is being cured. If the light intensity of the region A1, for example, is increased in a short time from the initiation time ts of irradiation, the pattern transferring material 70 is rapidly cured from a soft state. Therefore, the shrinkage amount that occurs with curing of the pattern transferring material 70 increases. On the other hand, like the light intensity of the region B1, the light intensity is slowly increased from the initiation time ts of irradiation, and the pattern transferring material 70 is slowly cured from a soft state. Therefore, the shrinkage amount that occurs with curing of the pattern transferring material 70 decreases.
The shrinkage amount of the pattern transferring material 70 in the irradiation plane R is regulated by giving the intensity distribution of light C in the irradiation plane R and changing the intensity distribution with time. In this way, regulation of the position after curing the pattern that is being transferred to the pattern transferring material 70 is carried out.
At time t1, the intensity of light of region A1 in the left-side region RL of the irradiation plane R is high, and the intensity of light in the regions A2 and A3 surrounding region A1 becomes lower as shown in
Further, as shown in
Namely, as shown in
When the irradiation plane R is irradiated with light at uniform intensity and the pattern transferring material 70 is cured as shown in
In the example shown in
When intensity distribution of light is provided to the irradiation plane R and the intensity distribution is changed with time as shown in
In the example shown in
In
The higher the variation of intensity of light C the greater the stress in the curing pattern as shown in
When adjoining two regions (first region r1 and second region r2 (
In the pattern formation apparatus 200 relating to this embodiment, irradiation of light C to the pattern transferring material 70 is controlled based on the data D showing the relation between the pattern feature slippage amount and direction of the embossed pattern 21 of the template 110 from the standard (for example, a foundation pattern), and change of intensity distribution of light C irradiating in the irradiation plane R with respect to time.
The data D may be determined by calculation in the control part 220 or may be inputted from outside by the input part 230.
Even when there is pattern feature slippage of the embossed protrusions and recesses of the negative of the three dimensional pattern of template 110, the slippage is modified when transferring to the pattern transferring material 70 and curing by the pattern formation apparatus 200 relating to this embodiment. Thus, a pattern is formed at a precise position with respect to the standard (for example, foundation pattern) by imprinting using template 110.
In
The light irradiation part 210A includes a scanning part 212 and the regulation part 215.
The scanning part 212 is a part wherein the irradiation position of light C is moved successively in the irradiation plane R in parallel to the main plane 10a of the base material 10 of template 110. In the scanning part 212, for instance, a movable mirror is installed to change the progress direction of light C released from the light source 217.
The regulation part 215 regulates the intensity of light C scanned from the scanning part 212 by the instruction of the control part 220. The regulation part 215 regulates the intensity of light C released from the light source 217 by directly controlling the light source 217. The regulation part 215 may regulate the quantity of light released from the light source 217 through a light-sensing device such as liquid crystal element, etc. The regulation part 215 regulates the intensity of light C in conjunction with the irradiation position of light C scanned by the scanning part 212. In this way, a prescribed intensity distribution is obtained in the irradiation plane R.
The scanning part 212 repeats scanning of light C in the irradiation plane R. The regulation part 215 conducts the regulation of light quantity so as to obtain one intensity distribution by scanning at least once light C in the irradiation plane R. The regulation part 215 regulates the quantity of light so as to change the intensity distribution together with repeating of scanning of light C in the irradiation plane R by the scanning part 212. The change of intensity distribution with time is carried out by scanning of light C multiple times to the irradiation plane R.
Even when the intensity distribution is obtained by scanning light C as above, the intensity of light C is regulated so as to make total irradiation quantity of the light C (accumulated irradiation quantity by plural scanning) in the irradiation plane R uniform.
In the scanning of light C by the scanning part 212, regulation of light quantity in rather minute regions on the irradiation plane R or continuous regulation of light quantity in the scanning direction is carried out.
The pattern formation method relating to this embodiment is an imprinting method of transferring the reverse image of the protrusions and recesses forming the three dimensional embossed pattern of the template to the pattern transferring material 70 using template 110 having an embossed pattern 21.
The template 110 to be used in the pattern formation method relating to this embodiment provides a base material 10 having main plane 10a and the embossed pattern 21 formed on the main plane 10a of the base material 10.
First, a pattern transferring material 70 is coated on the substrate 60 as shown in step S101. The pattern transferring material 70 is a photosensitive material. A photo-curable organic substance is used as the photosensitive material.
Next, the template 110 is positioned to be in contact with the pattern transferring material 70 as shown in step S102. In this way, the pattern transferring material 70 flows into depressions as part of the embossed pattern of the template 110.
Next, the pattern transferring material 70 is cured after contacting of the template 110 to the pattern transferring material 70 as shown in step S103. Since a photo-curable organic substance is used as the pattern transferring material 70 in this embodiment, the pattern transferring material 70 is curable by irradiating with light (for instance, ultraviolet ray) C.
After curing the pattern transferring material 70, the template 110 is removed as shown in step S104. In this way, the embossed pattern 21 of the template 110 is transferred to the pattern transferring material 70. A reversed embossed transfer pattern 70a, i.e., a negative image of the three dimensional features of the pattern 21 of protrusions and recesses on the template 110, (
In the pattern formation method relating to this embodiment, the intensity distribution of light C in the irradiation plane R in parallel to the main plain 10a is changed with time in the step of curing the pattern transferring material 70 as shown in step S103.
In
First, a pattern transferring material 70 is formed on the substrate 60 as shown in
As the pattern transferring material 70, a photo-curable organic substance, as an example, is used. The pattern transferring material 70 is dropped on the substrate 60, for instance, from nozzle N by ink jet method. Furthermore, the pattern transferring material 70 may be formed uniformly by spin coat, etc.
Then, a template 110 as shown in
Next, the embossed pattern 21 of the template 110 makes contact with the pattern transferring material 70. The pattern transferring material 70 flows into a plurality of depressions 21b of the embossed pattern 21 by capillary phenomenon to fill in the depressions 21b.
Next, light C is irradiated from the base material 10 side of template 110 to the pattern transferring material 70 in contact with the embossed pattern of the template 110. The light C is, for example, ultraviolet ray. The light C penetrates the base material 10 and the concave-convex pattern 21 and irradiates to the pattern transferring material 70. The pattern transferring material 70 from a photo-curable organic substance is cured by irradiating with light C.
In the irradiation of light C, as explained previously, the intensity distribution of light C in the irradiation plane R in parallel to the main plane 10a is changed with time. This regulates the stress by shrinkage in curing the pattern transferring material 70.
Next, the template 110 is removed from the pattern transferring material 70 as shown in
In contacting the template 110 to the pattern transferring material 70, sometimes it is desirable that a plurality of protrusions 21a of the embossed pattern 21 do not contact the surface of the substrate 60. In this case, a portion of the pattern transferring material 70 remains interposed between the surface of the substrate 60 and the protrusion and recess pattern 21a and the template 110 is then removed. The pattern transferring material 70 remains at the bottom of the depressions in the pattern of the transfer pattern 70a.
Further, when the substrate 60 is processed by using the transfer pattern 70a as mask, the substrate 60 is etched by, for instance, anisotropic RIE (Reactive Ion Etching). During etching, the thin portion of the pattern transfer material 70 at the base of the recesses of the material is etched away, while the portions of the pattern transfer material extending from the substrate 60 are etched as well, but because they are thicker they continue to mask the underlying portions of the wafer from the etch chemistry. As a result, a pattern is etched into the substrate having the same three dimensional pattern as the protrusions and recesses of the pattern transferring material. After etching, the transfer pattern 70a is removed. In this way, a pattern corresponding to the transfer pattern 70a is formed on the substrate 60. A pattern is formed on the substrate 60 including the semiconductor layer 60S to complete the semiconductor device 300.
In the imprinting method, each process shown in
In the production method of semiconductor device 300 by applying the pattern formation method as above, patterns, the feature or pattern slippage of which are modified based on the standards (for instance, position of an element formed on the semiconductor layer 60S or foundation pattern) of the embossed pattern 21 of the template 110, such as transfer pattern 70a, etc. result. When a pattern such as transfer pattern 70a, etc. is formed on the foundation pattern, the position setting with respect to the foundation pattern is carried out precisely. By methods described herein, the semiconductor device 300 having high positional accuracy of a plurality of transfer patterns is provided.
As explained above, according to pattern formation apparatus relating to this embodiment, pattern formation method, and production method of semiconductor device, pattern formation under consideration of position slippage of embossed pattern of a template can be carried out.
Although the embodiment of the present invention was explained above, the present invention is not limited to this only. For instance, the intensity distribution of light C explained above is an example, and it is suitably established according to the amount of slippage and direction of slippage with respect to the standard of the embossed pattern 21. Furthermore, those obtained by suitably adding, and deleting constitutional elements, and modifying the design thereof with respect to the each embodiment by professions of this field, and those obtained by combining suitably the characteristic of each embodiment are included in the scope of the present invention as long as it provides the gist of the present invention.
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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2012-039325 | Feb 2012 | JP | national |