JP3603779B2 - Electron detection device, charged particle beam device, semiconductor integrated circuit device, and processing, observation, and inspection method of the semiconductor integrated circuit device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention uses a charged particle beam device, a charged particle beam device used for observation and inspection of a semiconductor integrated circuit device and the like, which is provided in the charged particle beam device and detects reflected electrons and secondary electrons. The present invention relates to a semiconductor integrated circuit device to be processed, observed, and inspected, or a method of processing, observing, and inspecting a semiconductor integrated circuit device.
[0002]
[Prior art]
BACKGROUND ART A charged particle beam device represented by a scanning electron microscope, a focused ion beam device, and an electron beam drawing device is a device that performs observation, processing, and drawing by irradiating a sample with an electron beam or an ion beam. Among them, electron beam lithography systems used in the manufacture and inspection of semiconductor integrated circuit devices, scanning electron microscopes for length measurement, and inspection systems that use scanning electron microscopes, etc., have smaller and smaller element sizes year by year. As a result, the position accuracy of the electron beam required for each device is increased. An electron beam lithography system irradiates a mark on a pallet holding a wafer with an electron beam to measure the position of a sample wafer, and uses an electron detector to process reflected electrons and secondary electrons from the mark. The position of the mark is measured. In a scanning electron microscope, a sample is irradiated with an electron beam, and an electron detector is used to process reflected electrons and secondary electrons from the sample, thereby obtaining an image of the sample. The electron detection device includes a detector that detects electrons and a holder that holds the detector. The holder not only holds the detector, but also has a structure corresponding to an opening for guiding electrons to the detector. Depending on the structure of the holder, the signal obtained by the detector is not limited to the reflected electrons and secondary electrons directly flying from the sample, but the reflected electrons and the like hit the parts other than the opening of the holder and become secondary reflected electrons. Secondary reflected electrons and the like again strike the sample, become tertiary reflected electrons, and include erroneous signals detected by the detector. These erroneous signals resulting from the detection of higher-order reflected electrons and the like lead to a decrease in image processing accuracy in a scanning electron microscope and a decrease in position accuracy in an electron beam writing apparatus. In addition, erroneous signals caused by higher-order reflected electrons and the like hinder improvements in image processing accuracy and positional accuracy, thereby slowing progress in miniaturization of element dimensions.
[0003]
As means for reducing the introduction of higher-order reflected electrons and the like into the detector, for example, a method has been proposed in which the surface of the holder other than the opening for introducing electrons is made into a diffraction grating shape to scatter reflected electrons. By scattering backscattered electrons, secondary backscattered electrons, which are the source of tertiary backscattered electrons that fly from the sample to the detector, are reduced, but tertiary or higher-order backscattered electrons are not reduced. Since there is no such effect, a great effect cannot be expected in reducing false signals.
[0004]
For the purpose of reducing the long-range photosensitive action, for example, as described in JP-A-61-19126, unevenness is provided on the opposite wall surface of the sample to scatter reflected electrons, so that secondary reflected electrons are generated. A method has been proposed to prevent re-incident on the sample. By such a method, secondary reflected electrons from the opposed wall surface of the sample are reduced, but higher-order reflected electrons scattered by the unevenness cannot be scattered above the opposed wall surface, and eventually the opposed wall surface is not scattered. Since it returns from the sample to the sample, a large effect cannot be expected in reducing high-order reflected electrons and the like.
[0005]
Further, for the purpose of reducing the long-distance photosensitive action and the beam drift, for example, as described in Japanese Patent Application Laid-Open No. 2000-2960413, an anti-reflection mechanism having an oblique honeycomb opening structure is provided on the sample and above the sample. There has been proposed a method of disposing between a structure and a structure to prevent reflected electrons from re-entering the sample as secondary reflected electrons. By such a method, secondary reflected electrons from the structure above the sample are reduced, but since the antireflection mechanism is a plate, the area of the remaining portion of the opening is large, and the remaining portion of the opening is large. No significant effect can be expected in reducing the third-order or higher-order backscattered electrons caused by the backscattered electrons.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to reduce erroneous signals caused by higher-order reflected electrons and higher-order secondary electrons that lower the detection accuracy of reflected electrons and the like.
[0007]
It is another object of the present invention to provide a semiconductor integrated circuit device which has been processed, observed, and inspected stably and with high precision by reducing the number of erroneous signals of the electron detection device, and has a finer element size, and a method of processing, observing and inspecting the same. Aim.
[0008]
[Means for Solving the Problems]
In an embodiment of the present invention, a detector for detecting electrons and a holder for holding the detector are provided, and when a charged particle beam is irradiated onto the sample to detect reflected electrons or secondary electrons from the sample, the holder Is composed of a plurality of cylinders having a spatula section. The spatula section has a structure in which the extension line intersects the intersection between the central axis of the charged particle beam and the sample. The spatula section has an angle for selectively introducing reflected electrons or secondary electrons within the sampling angle range with respect to the central axis of the charged particle beam to the detector, and between the cylinders having these spatula sections. Position the detector. To prevent reflected or secondary electrons outside the sampling angle range from becoming higher-order reflected or higher-order secondary electrons, selectively use reflected or secondary electrons outside the sampling angle range. The tube provided with the spatula restricting portion is disposed inside and outside the tube provided with the spatula restricting portion at an angle for selectively introducing reflected electrons or secondary electrons within the sampling angle range to the detector. Even if the reflected electrons or secondary electrons hitting the tip of the spatula are turned into secondary reflected electrons or secondary electrons, the tips of the spatula stops are not introduced into the detector. By selectively introducing reflected electrons or secondary electrons within the sampling angle range to the detector and selectively capturing reflected electrons or secondary electrons outside the sampling angle range, higher-order reflected electrons can be obtained. The erroneous signal caused by the high-order secondary electrons is reduced, and the detection accuracy of the reflected electrons or the secondary electrons can be improved.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Example 1)
FIG. 1 is a schematic longitudinal sectional view showing the structure of an electron beam writing apparatus to which the first embodiment of the present invention is applied, FIG. 2 is a longitudinal sectional view showing the structure of an electron detecting apparatus in the prior art, and FIG. It is a longitudinal section showing the structure of the electronic detection device in a 1st example of the present invention. In this embodiment, an electron beam lithography apparatus will be described as an example. However, it is easy to apply this embodiment to another charged particle beam apparatus.
[0010]
In the electron beam drawing apparatus shown in FIG. 1, the electron beam 17 emitted from the electron gun 1 is formed into a circular shape by the stop 2, irradiated on the stop 5, and imaged on the stop 8 by the lens 9. The image on the stop 8 is projected by the lens 10, passes through the stop 11, and enters the lens 14. Further, the light is projected and deflected by the lens 14 and the deflector 13, and is projected and drawn on the sample 18 coated with the photosensitive agent. At this time, a pattern-shaped opening provided in advance in the stop 8 is selected by the deflector 7. The drawing is performed by moving the stage 19 except for the area where the deflector 13 can deflect. The reflected electrons 29 from the mark 28 placed on the sample for alignment are detected by the detector 15 of the electron detection device, and the position of the stage 19 is measured by a signal from the laser length measuring device 26.
[0011]
As shown in FIG. 2, in the shape of the holder 30 using the conventional technique, higher-order reflected electrons 35 due to reflected electrons 34 and the like hitting the holder surface other than the opening 33 for introducing the reflected electrons 31 and the like into the detector 32, 36 and the like fly to the detector 32 and increase the number of false signals. This is one of the causes for lowering the accuracy of signal processing. Also, higher-order reflected electrons 38 such as reflected electrons 37 hitting the bottom of the holder may affect the sample 39.
[0012]
The means for solving this problem in the present invention will be described below. Here, as shown in FIG. 3, the holder is composed of a plurality of cylinders 41, 42, 43, 44 provided with a spatula. A detector 49 is arranged between the cylinders 42 and 43 having the spatula sections 46 and 47 in a desired sampling angle range 45. The spatula portions 46 and 47 of the cylinders 42 and 43 sandwiching the detector 49 selectively introduce only the backscattered electrons 51 directly flying from the sample 50. The tube 41 or the spatula portion 48 outside the sampling angle range 45 captures the reflected electrons 52 and 53 flying from the sample 50 so as not to become higher-order reflected electrons, and the like. Higher order backscattered electrons 56, 57, 58, etc. due to backscattered electrons 54, 55, etc. hitting the tip are also captured and prevented from being introduced into the detector 49. Furthermore, the backscattered electrons 64 and the like flying outside the spatula of the outermost tube do not hit the spatula, so they do not become higher-order backscattered electrons and do not enter the sample 50 and affect them. Cylinder 41, 42, 43, 44 or spatula narrowing section 46,
The positional relationship between the tips of 47 and 48 is such that the angle 60 between the innermost cylinder 41 and the trajectory 59 of the reflected electrons 54 hitting the tip of this cylinder 41 is on a straight line 62 with the innermost cylinder 41 being axially symmetric. The tip of the spatula narrowing portion 46 of the inner cylinder 42 sandwiching the detector is arranged, and the tip of the spatula narrowing portion 47 of the outer cylinder 43 sandwiching the detector 49 and the tip of the spatula narrowing portion 48 outside the sampling angle range 45. Is assumed to be parallel to the sample 50. This makes it possible to reduce erroneous signals due to higher-order reflected electrons and the like.
(Example 2)
FIG. 4 is a longitudinal sectional view showing the structure of the electron detection device according to the second embodiment of the present invention. The drawing operation is performed in the same manner as in the first embodiment. Here, as shown in FIG. 4, the holder is composed of a plurality of cylinders 66, 67, 68, 69 each having a spatula. A detector 74 is arranged between cylinders 67 and 68 having spatula portions 71 and 72 in a desired sampling angle range 70. The spatula restricting portions 71 and 72 of the cylinders 67 and 68 sandwiching the detector 74 selectively introduce only the backscattered electrons 76 directly flying from the sample 75. The tube 66 or the spatula 73 outside the sampling angle range 70 captures reflected electrons 77 and 78 flying from the sample 75 so as not to become higher-order reflected electrons and the like. Higher order backscattered electrons 80 and the like due to backscattered electrons 79 and the like striking the tip are also captured, and are prevented from being introduced into the detector 74. Further, the backscattered electrons 81 and the like flying outside the spatula 73 of the outermost cylinder 69 do not hit the spatula, so that they do not become higher-order backscattered electrons or the like, and may be incident on the sample 75 and affect them. Absent. The positional relationship between the ends of the cylinders 66, 67, 68, 69 or the spatula constrictions 71, 72, 73 is determined by the spatula constriction 71 of the inner cylinder 67 sandwiching the detector 74 on a straight line 82 extending the innermost cylinder 66. The straight line 83 connecting the tip of the spatula stop 72 of the outer tube 68 sandwiching the detector 74 and the tip of the spatula stop 73 outside the sampling angle range 70 is parallel to the sample 75. . This makes it possible to reduce erroneous signals due to higher-order reflected electrons and the like.
(Example 3)
Although the above embodiment has shown the electron beam writing apparatus, the electron detection apparatus of the present invention can be easily applied to a scanning electron microscope and an inspection apparatus to which the scanning electron microscope is applied. Further, if the electron gun is replaced with an ion gun, the electron beam is replaced with an ion beam, and the reflected electrons from the sample are replaced with secondary electrons, the present invention can be applied to a focused ion beam apparatus. At this time, the lens, aperture, and other mechanisms of the ion beam have the same functions as those of the electron beam device.
(Example 4)
A manufacturing process of a semiconductor integrated circuit using an electron beam drawing method using an electron beam drawing device provided with the electron detection device of the present invention will be described.
[0013]
A P well layer, a P layer, a field oxide film, a polycrystalline silicon / silicon oxide film gate, a P high concentration diffusion layer, an N high concentration diffusion layer, and the like are formed on an N minus silicon substrate by a usual method. Next, an insulating film of phosphor glass (PSG) is applied, and the insulating film is dry-etched to form a contact hole.
[0014]
Next, a W / TiN electrode wiring material is applied by a usual method, a photosensitive agent is applied thereon, and the photosensitive agent is patterned by using the electron beam drawing method of the present invention. Then, W / TiN electrode wiring is formed by dry etching or the like.
[0015]
Next, an interlayer insulating film was formed, and a hole pattern was formed by a usual method. The hole pattern is buried with a W plug to connect an Al wiring or a Cu wiring. The subsequent passivation process uses a conventional method.
[0016]
In this example, only the main manufacturing process was described, but the same process as the conventional method was used except that the electron beam drawing method of the present invention was used in the lithography process for forming the W / TiN electrode wiring. Through the above steps, a fine pattern can be formed without lowering the quality, and a CMOS LSI can be manufactured with a high yield. As a result of manufacturing a semiconductor integrated circuit using the electron beam lithography apparatus of the present invention, the yield was improved due to the improved mark detection accuracy, and the production amount could be increased.
[0017]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce erroneous signals caused by higher-order reflected electrons and higher-order secondary electrons that lower the detection accuracy of reflected electrons and the like.
[0018]
Further, it is possible to provide a semiconductor integrated circuit device which has been processed, observed, and inspected stably and with high precision by reducing the erroneous signal of the electron detection device, and has a fine element size, and a method of processing, observing and inspecting the same. it can.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a configuration of an electron beam writing apparatus to which a first embodiment of the present invention is applied.
FIG. 2 is a longitudinal sectional view showing the structure of an electron detection device in a conventional technique.
FIG. 3 is a longitudinal sectional view showing the structure of an electron detection device according to the first embodiment of the present invention.
FIG. 4 is a longitudinal sectional view showing the structure of an electron detection device according to the first embodiment of the present invention.
[Explanation of symbols]
12, 30, holder, 15, 32, 49, 74 detector, 17 electron beam, 18, 39, 50, 75 sample, 19 stage, 23 control computer, 28 mark, 29, 31, 34, 37, 51, 52, 53, 54, 55, 64, 76, 77, 78, 79, 81: reflected electrons, 33: aperture, 35, 38, 56, 58, 80: secondary reflected electrons, 36, 57 tertiary backscattered electrons, 41, 42, 43,
44, 66, 67, 68, 69 ... cylinder, 45 ... sampling angle range, 46, 47, 48, 71, 72, 73 ... spatula narrowing section, 59 ... locus, 60 ... angle.

Claims (3)

An electron detection device, comprising: a detector for detecting electrons; and a holder for holding the detector, wherein the holder is a spatula in an electron detection device that irradiates a charged particle beam onto a sample and detects reflected electrons or secondary electrons from the sample. It is composed of a plurality of cylinders having an aperture portion, and the spatula aperture portion has an extension line intersecting the intersection of the center axis of the charged particle beam and the sample, and is sampled based on the central axis of the spatula aperture portion. The detector is arranged between a cylinder having a spatula section for selectively introducing reflected electrons or secondary electrons within an angle range, and the reflected electrons outside the sampling angle range of the spatula section. Alternatively, there is provided an electron detection device including a cylinder provided with a spatula section for selectively capturing secondary electrons. A charged particle source for generating a charged particle beam, a deflector for deflecting the charged particle beam, and a diaphragm having a hole for limiting the shape of the charged particle beam, and irradiating the sample with the charged particle beam. A charged particle beam apparatus for observing, processing, or drawing the sample, comprising a detector for detecting electrons and a detector for detecting reflected electrons or secondary electrons from the sample; And a holder comprising a plurality of cylinders having a spatula section, wherein the spatula diaphragm section has an extension line intersecting the intersection of the center axis of the charged particle beam and the sample, and the central axis The detector is arranged between a cylinder having a spatula section for selectively introducing reflected electrons or secondary electrons within the sampling angle range with reference to the reflected electrons or outside the sampling angle range. two A charged particle beam apparatus characterized by comprising a cylinder with a spatula throttle portion for selectively captures electrons. It comprises a detector for detecting electrons and a holder for carrying the detector, wherein the holder comprises a plurality of cylinders provided with a spatula, and the spatula is a central axis of the charged particle beam having an extended line extending therefrom. The detector intersects the intersection with the sample, and the detector is disposed between a cylinder having a spatula section for selectively introducing reflected electrons or secondary electrons within the sampling angle range with respect to the central axis. Electrons are irradiated and processed by a charged particle beam apparatus having a cylinder provided with a spatula section for selectively capturing reflected electrons or secondary electrons outside the sampling angle range, and the generated reflected electrons or secondary electrons are generated. A method of processing, observing, and inspecting a semiconductor integrated circuit device, wherein electrons are detected, observed, or inspected.

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