WO2008032416A1

WO2008032416A1 - Alignment chip for scanning electron microscope point aberration measurement

Info

Publication number: WO2008032416A1
Application number: PCT/JP2006/318796
Authority: WO
Inventors: Kenya Ohashi; Shinsuke Minata; Yasunori Shoji; Katsunori Nakajima
Original assignee: Hitachi High-Technologies Corporation
Priority date: 2006-09-15
Filing date: 2006-09-15
Publication date: 2008-03-20
Also published as: JP4654299B2; JPWO2008032416A1

Abstract

Provided is an alignment chip for point aberration correction measurement for a scanning electron microscope. The alignment chip can be simply manufactured at a low cost and is provided with a novel alignment pattern suitable for point aberration correction measurement. The alignment chip has an uneven pattern on the surface, and the uneven pattern has a protruding section or a recessed section configuring a circular or polygonal closed loop.

Description

細細畚, Scanning electron microscope point aberration measurement alignment chip

The present invention relates to a alignment chip for measuring and adjusting point aberrations installed in a scanning electron microscope and a pattern forming mold for forming an alignment pattern by imprinting. Background Technology '.

: In recent years, semiconductor integrated circuits have been miniaturized and stacked, and the precision of photolithography equipment has been promoted as a pattern transfer technology for realizing fine processing. However, the processing method is approaching the wavelength of the light source for light exposure, and the photolithography technology is approaching its limit. Therefore, in order to advance further miniaturization and higher integration, an electron beam lithography apparatus, which is a kind of charged particle beam apparatus, has been used in place of photolithography technology. Unlike the batch exposure method that uses a light source such as an i-line or excimer laser, the pattern that uses an electron beam is drawn in a mask pattern, so there are many patterns to be drawn. The more it takes, the longer it takes to expose (draw), and the longer it takes to form the pattern. Therefore, as the degree of integration increases dramatically, such as 256-megabit, 1-gigabit, and 4-gigabit, the pattern formation time will increase dramatically, and the throughput may be significantly inferior. Concerned. Therefore, in order to increase the speed of the electron beam lithography system, various shapes of masks are combined, and they are collectively irradiated with an electron beam. Development is underway. But of the pattern T JP2006 / 318796

2

While miniaturization is progressing, the electron beam lithography system has to be increased in size, and a mechanism for controlling the mask position with higher accuracy is required. .

Scanning electron microscopes also use this microfabrication technology in the preparation of alignment tips for measuring point aberrations, and are commonly used as a studama adjustment sample, especially for high-precision observation operation microscopes. . However, the lithography technology for producing this point aberration measurement pattern is approaching its limit, and a new pattern formation method has become necessary.

On the other hand, US Pat. No. 5, 7 72, 90 5 discloses a technique for performing fine pattern formation at a low cost. This is because a predetermined pattern is transferred by embossing a mold having the same pattern as the pattern to be formed on the substrate against the resist film layer formed on the surface of the substrate to be transferred. Is. In particular, according to the nanoprint technology described in Japanese Patent Application Laid-Open No. 2 0 4-7 7 1 5 8 7, a silicon wafer can be used as a mold, and a microstructure less than 25 nanometers can be formed by transfer. It is said that there is. Disclosure of the invention

The present inventors have studied an imprint technique capable of forming a fine pattern for point aberration correction measurement of a scanning microscope. As a result, the alignment having a conventional fine concentric cylindrical stacked alignment pattern is performed. The following problems were found when forming the tip with the imprinting technology. First, lithography technology for creating a new mold having a fine concentric columnar alignment pattern is not easy and requires a lot of time and cost. In addition, when creating a new mold, Therefore, it is necessary to find the conditions for adjusting the focal position to create an unclear concentric circle by using lithography technology, and it is very difficult to form many fine patterns on the same mold because of poor reproducibility. It is.

Patent Document 2 discloses a technique for forming multi-level unevenness as a mold transfer pattern structure. However, when the inventors conducted a transfer experiment using a mold having a multi-stage structure, it was difficult to obtain the verticality of the uneven side wall surface suitable for point aberration correction measurement. It turns out that a mold structure is necessary.

The present invention solves the above-mentioned problems, and can be easily manufactured at a low cost in an alignment chip for measuring point aberration correction of a scanning electron microscope, and is a novel key suitable for point aberration correction measurement. An object of the present invention is to provide an alignment chip having a alignment pattern.

In addition, the present invention provides a pattern forming mold for a point aberration correction measurement alignment chip and a method for manufacturing the alignment chip for manufacturing the alignment pattern of the alignment chip with high accuracy and low cost. The purpose is to provide

The present invention provides an alignment chip for measuring a point aberration of a scanning electron microscope having an uneven pattern on a surface thereof, wherein the uneven pattern comprises a circular or polygonal closed loop (concentric tube or polygonal tube shape). It features an alignment chip having convex or concave portions.

Also, a pattern forming mold for transferring the concavo-convex pattern onto the transfer body by pressing the concavo-convex pattern formed on the surface onto the transfer body, and the concavo-convex pattern forms a circular or polygonal closed loop. It is characterized by a mold for forming an astigmatism measurement alignment pattern having convex or concave portions. Also, a method for manufacturing an alignment chip for measuring point aberrations in a scanning electron microscope, the method comprising pressing a mold having a concavo-convex pattern forming a circular or polygonal closed loop on a surface thereof onto a substrate to be transferred; Separating the mold from the substrate to be transferred, and transferring the concavo-convex pattern to the surface of the substrate to be transferred. '

According to the present invention, by forming an alignment tip provided with a circular tubular or polygonal tubular convex part, irradiating the concave wall surface constituting the circular tubular or polygonal tube with a turtle line causes point aberration. Can be corrected. 'Also, this circular or polygonal tubular convex part can be adjusted by adjusting its diameter dimension, and multiple convex parts with different diameters can be produced by nano-printing. It is possible to cope with point aberration correction when using a microscope. .

According to the present invention, it is possible to provide an alignment chip that can be easily manufactured at low cost and has a novel alignment pattern suitable for point aberration correction measurement. In addition, it is possible to provide a pattern forming mold for the alignment correction chip and a method for manufacturing the alignment chip, in which the alignment pattern of the alignment chip is manufactured with high accuracy and low cost. Brief description of the drawings ''

FIG. 1 is an explanatory view of a cross-sectional structure showing an example of a dot aberration measurement alignment pattern of this embodiment, (a) is a cross-sectional view of a transferred structure, and (b) is an observation view from above. . ·

FIG. 2 is a cross-sectional view of a mold having a concave circular tube diameter portion of the mold as a cut surface. FIG. 3 is a schematic diagram of a transferred structure having circular tube groups having different diameters. It is an example which shows the shape of a lement chip.

FIG. 4 is an example showing the shape of the alignment tip by the transferred structure having a polygonal tube group having different diameters.

Fig. 5 is a graph showing the change in the resin filling rate on the pattern wall surface with respect to the area within the loop of the pattern in nanoimprinting.

FIG. 6 is a graph showing the number of measurements until completion of the measurement of point aberration with respect to the loop height of the putter in nanoimprint. BEST MODE FOR CARRYING OUT THE INVENTION (1) A nanoprint pattern forming mold according to this embodiment will be described below. Nanoimprint means transfer in the range of about 100 m to several nm. .

The mold for forming a nanoimprint pattern according to this embodiment (hereinafter abbreviated as a mold) is for transferring a nano-level pattern to a transferred structure, and the nano-level pattern is transferred to the transferred structure. It has a pattern forming section for transferring. This pattern forming portion has a point-symmetric structure, and has a plurality of concave microstructures for forming convex portions having a shape capable of correcting point aberration called “studama adjustment using an electron beam”. Point aberration correction is based on the point aberration correction program built in the computer in the electron microscope in advance and detects aberration deviations in all directions and performs feed pack control of the electron beam irradiation angle. The fine pattern for that purpose may be a shape having a side wall having a single point-symmetrical outline. For example, if a circular tube with an inner diameter of 50 nm and an outer diameter of 7 O nm is a convex part formed on the surface of a transfer medium with a height of 100 nm, the point aberration correction called studama adjustment is performed on this circle. The electron beam applied to the inner and outer peripheral surfaces of the tube is reflected and formed. The reflected electron beam is detected in the region where the deviation exceeds 20%, that is, 2 nm with respect to 10 nm, which is the wall thickness indicated by the radius difference between the inner and outer circumferences. If this happens, control the electron beam direction by controlling the insulator lens. At this time, the alignment tip is formed by the mold having the concavo-convex pattern constituting the concentric circle or the polygonal closed loop, so that the shape having the side wall described above is formed. Therefore, in the scanning electron microscope Point aberration correction can be performed quickly. In addition, by arranging a plurality of circular tubes with such side walls in a lattice pattern at a pitch of 200 nm, even if the transfer due to nanoprinting is partially lost, it is compensated and point aberration that maintains accuracy. Correction is possible. The mold for forming the transferred structure has a shape in which a circular tube or a polygonal tube forms a hole in the concave portion because the uneven pattern is obtained by inverting the unevenness of the transferred structure. The method for forming the concave portion for pattern formation described above in the mold is not particularly limited as long as the target forming portion can be formed. For example, photolithography uses electron beam drawing. Method, replica production by nanoimprint, etc., can be selected as appropriate according to the desired processing accuracy. A release material layer for facilitating separation from the transfer pattern forming layer of the transfer substrate may be provided on the outermost surface of the mold on which the pattern forming portion is formed. The release material layer is preferably a heat resistant resin such as a fluorine compound or a fluorine mixture.

According to the present invention, point aberration correction of a scanning electron microscope can be performed in a short time. In addition, when using microscopes with different measurement magnifications, stigma adjustment at the observation magnification can be performed by using alignment tips having different diameters. Furthermore, by nanoimprinting, 'by manufacturing the alignment chip, the cost of measuring and correcting astigmatism components is significantly increased. Can be reduced. In other words, the use of a mold in which concentric tubes or polygonal tubes having different diameters are formed in advance enables high-precision and high-efficiency point correction of a scanning electron microscope.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Example 1)

FIG. 1 is an explanatory diagram of a cross-sectional structure showing an example of a point aberration measurement client pattern of the present embodiment. A spin coater was used on a Si wafer 1 a having a diameter of 6 inch φ (15 cm φ) X thickness of about 0.5 mm, and a coating film 1 of 0.5 was formed from a thermoplastic resin resist I. Subsequently, using an electron beam drawing device J BX 6 0 0 FS (manufactured by JEOL Ltd.), the mold of the concave portion of the fine circular tube obtained by exposure by direct drawing with the electron beam EB and development. As a result, the tubular pattern 1 c was transferred to the thermoplastic resin resist ridge. When this transferred structure is viewed from above, there are cylindrical projections (convex portions) Id arranged in a lattice at a constant pitch. Fig. 2 shows a cross-sectional view of the mold with the diameter of the concave circular tube of the mold as the cut surface. In this way, the mold has a circular tube with an inner diameter of 50 nm and an outer diameter of 70 nm, a depth of 10 O nm, and recesses 2a. It has become. This mold is formed by directly drawing the silicon substrate 2b with an electron beam. If the pattern of the resist 1b is on the order of several hundred nm or more, Kr laser (wavelength 35 1 nm) or the like may be used instead of the electron beam. Using resist 1b with irregularities as a mask pattern, dry etching of Si wafer or Ni metal, forming irregularities on the Si surface or Ni metal surface, and then removing resist 1b by 0 ₂ ashing The mold can also be made again. Through the above process, a transferred structure having a cylindrical recess with a diameter of 100 nm formed on the surface is obtained. Tochip was installed in the scanning electron microscope.

Here, the substrate main body of the substrate to be transferred is not particularly limited as long as a target member can be formed, and may have any predetermined strength. Specifically, silicon, various metal materials, glass, ceramics, plastics, etc. are preferably applied.

The transfer pattern forming layer of the substrate to be transferred is not particularly limited as long as a target member can be formed, and is selected according to desired processing accuracy. Specifically, polyethylene, polypropylene, polyvinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, polyvinyl chloride, polystyrene, ABS resin, AS resin, acrylic resin, polyamide, polyacetylene terephthalate Taleate, glass-reinforced polyethylene terephthalate, polycarbonate, modified polyphenylene ether, polyphenylene sulfide, polyetheretherketone, liquid crystalline polymer, fluororesin, polyarate, polysulfone, polyethersulfone, polyamidoimi. Thermoplastic resins such as polyamide, polyether imide, thermoplastic polyimide, phenol resin, melamine resin, urea resin, epoxy resin, unsaturated polyester resin, alkyd resin, silicon resin Thermosetting resins such as aryl phthalate resin, polyamide bismaleimide, and polybisamide triazole, and materials in which two or more of these are blended can be used. As these resins, a resin that does not generate gas in a scanning electron microscope or a resin that suppresses an electron beam irradiation decomposition reaction in a scanning electron microscope is preferable. The transfer pattern forming layer is not limited to a resin, and inorganic glass, a low melting point metal, or the like can be used.

(Example 2) FIG. 3 is an example showing the shape of the alignment chip by the transferred structure having a group of circular tubes having different diameters. By arranging circular tubes with different diameters on the same substrate, it is possible to reduce errors in correction of point aberration caused by adjusting the magnification when performing point aberration correction measurement of a scanning electron microscope. Here, the substrate main body of the substrate to be transferred is not particularly limited as long as it can form a target member, and may have a predetermined strength. Specifically, silicon, various metal materials, glass, ceramic, plastic, etc. are preferably applied.

(Example 3) '

-Fig. 4 shows an example of the shape of the alignment tip by the transferred structure having a polygonal tube group having different diameters. By arranging polygonal tubes of different sizes on the same substrate, it is possible to reduce point aberration correction errors caused by adjusting the magnification when performing scanning aberration measurement with a scanning electron microscope. Here, the substrate body of the substrate to be transferred is not particularly limited as long as a target member can be formed, and may have a predetermined strength. Specifically, silicon, various metal materials, glass, ceramic, plastic, etc. are preferably applied. -

(Example 4)

In molds that transfer nano-level patterns, circular or polygonal closed-loop concavo-convex parts are formed on the transferred member, so that the outer periphery of the circular or polygonal tube can be formed by photolithography or electron beam direct drawing. The mold in which the concave shape is formed so that the area in the closed loop formed by this is from l OO nm ² to l OOOO nm ² is used for nanoimprinting. Due to the mold having this area, the resin on the substrate of the component to be transferred, or the resin with the resin itself as the substrate can be fluidly filled in the fine pattern. 0

I understood that. When the area inside the loop is 60 nm ² or less, the filling rate is 70% or less. Therefore, the wall inclination angle required for point aberration correction measurement is 85 degrees or more, but when the area inside the loop is 60 nm ² or less, it is 80 degrees or less, indicating that it is not suitable for point aberration correction. . Figure 5 shows an example of the results. On the other hand, if the area in the closed loop formed by the outer circumference of the circular tube or polygonal tube is 100000 nm ² or more, when correcting the point aberration at a magnification of 10,000 times or more, it is moved when measuring the deviation. Since the distance of the electron beam is large, it was found that correction that maintains high accuracy was possible, but it was not possible.

: (Example 5)

By transferring the nano-level pattern by nanoimprinting, a circular or polygonal closed-loop concavo-convex part is formed on the transferred member, and the step between the closed-loop concave or convex part and the peripheral flat part is 1 0 The resin filling rate by nanoimprinting was measured from 0 nm to 1000 nm. Figure 6 shows an example of the results. The number of pattern movements until point aberration measurement refers to whether or not point convergence can be achieved with a single pattern, and if this is not possible due to poor shape, the next pattern is selected as the measurement target, and the electron beam irradiation range Indicates the number of operations to change. It was found that measurement of point aberrations became impossible when the step was 50 nm or less, and the wall height was required to be at least 60 nm.

(Example 6)

When the tube thickness, which is the thickness of the wall surface of the closed loop formed by the circular tube, is changed from 10 nm to 100 nm in a member to which a nano-level circular tube pattern is transferred, It was found that point aberration correction measurement with a scanning electron microscope is possible. At this time, the circular pipe can be a point-symmetric polygonal pipe. It is.

(Example 7)

The mold for transferring the nano-level pattern is composed of nickel or nickel alloy with a concave part of the circular tube, and it is repeatedly transferred by having a fluorine-based molecular layer for release on the transfer pattern display. It was found that the structure can be fabricated. '

(Example 8)

The transferred structure is essentially composed of an i¾ plastic resin that softens by reaching the glass transition point by predetermined heating. However, it can be seen that the same fine pattern can be transferred even if it is composed of a transfer pattern forming layer composed of a thermoplastic resin that is softened by heating at a predetermined temperature on a silicon substrate. At this time, it was found that when the thickness of the thermoplastic resin is 1 j m, the cylindrical convex portion can be formed and held without deviating from the substrate.

Claims

2

Claims' 1. In the alignment chip for point aberration measurement of a scanning electron microscope having a concavo-convex pattern on the surface, the concavo-convex pattern has a convex part or a concave part constituting a circular or polygonal closed loop. Alignment chip characterized by

2. The alignment chip according to claim 1, wherein at least two or more convex portions or concave portions constituting the circular or polygonal closed loop are formed. '

3. The alignment tip according to claim 2, comprising the closed loops having different diameters.

4. In § Lai Instruments chip according to claim 1, § Lai instrument tip the closed loop area of the projections or recesses to configure and wherein the 1 0 0 0 0 nm ² Dearuko 'from 1 0 0 nm ^z .

5. The alignment chip according to claim 1, wherein a step between a convex portion or a 'concave portion constituting the closed loop and a peripheral flat portion is from 100 nm to 100 00 rim. Alignment chip.

6. A pattern forming mold for transferring the concavo-convex pattern to the transferred body by pressing the concavo-convex pattern formed on the surface against the transferred body, wherein the concavo-convex pattern is circular or polygonal A mold for forming an astigmatism measurement alignment pattern, characterized by having a convex portion or a concave portion constituting a closed loop.

7. The mold for forming an astigmatism measurement alignment pattern according to claim 6, wherein at least two or more convex portions or concave portions constituting the circular or polygonal closed loop are formed.

8. In the mold for forming the alignment aberration component for the point aberration measurement, the diameter is different. A mold for forming an aberration measurement alignment pattern, characterized by having the closed loop.

9. The area of the convex part or concave part constituting the closed loop is from 100 nm ²

The point aberration measurement mold for forming an alignment pattern according to claim 6, wherein the mold is 1 0 0 0 0 nm ² . '

10. The point aberration measurement alignment pattern according to claim 6, wherein a step between a convex portion or a concave portion constituting the closed loop and a peripheral flat portion is from 100 nm to 100 nm. Mold for forming.

11. The point aberration measurement alignment pattern according to claim 6, which is made of nickel or a nickel alloy, and has a molecular layer for releasing from the surface of the uneven pattern. Mold for forming.

1 2. A method of manufacturing an alignment tip for measuring the point aberration of a scanning electron microscope,

Pressing a mold having a concavo-convex pattern forming a circular or polygonal closed loop on the surface against the substrate to be transferred;

And a step of peeling the mold from the substrate to be transferred, and transferring the concave / convex pattern onto the surface of the substrate to be transferred.

1 3. The substrate to be transferred is composed of a thermoplastic resin that softens by reaching a glass transition point by a predetermined heating, or a thermoplastic resin that softens by a heating action of a silicon substrate and a predetermined temperature 13. The alignment chip manufacturing method according to claim 12, further comprising: a transfer pattern forming layer configured by:

14. The alignment chip manufacturing method according to claim 13, wherein the resin portion has a thickness of 1 or more.