JP2002141013A - Electron detecting device, charged particle beam device, semiconductor integrated circuit device, and processing, observation, inspection methods for semiconductor integrated circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an erroneous signal caused by reflected electron of higher order or secondary electron which lower the detection accuracy of the reflected electron. SOLUTION: For the electron detecting device of which, a holder is composed of a plurality of cylinders having a spinning part, a detector is mounted inside the cylinder having the spinning part with an intended intake angle, and the spinning part of the cylinder having a detector selectively collects only the reflected electron directly traveled from a sample. The cylinder or the spinning part with not intended intake angle catches the reflected electron or the like traveled from the sample so as not to make them become the reflected electron of higher order or the like, and also catches the reflected electron of higher order collided against the top end part of the cylinder or the spinning part, and prevents the detector from receiving the reflected electron of higher order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam device used for observation and inspection of a semiconductor integrated circuit device, an electron detection device for detecting reflected electrons and secondary electrons, etc. The present invention relates to a semiconductor integrated circuit device that is processed, observed, and inspected using a charged particle beam device, or a method of processing, observing, and inspecting a semiconductor integrated circuit device.

[0002]

2. Description of the Related Art A charged particle beam apparatus typified by a scanning electron microscope, a focused ion beam apparatus, and an electron beam drawing apparatus is an apparatus for irradiating an electron beam or an ion beam onto a sample for observation, processing, and drawing. . 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 increasingly smaller target 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 wafer as a sample, 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 to obtain 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 reflected electrons and secondary electrons directly flying from the sample. 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 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 drawing apparatus. In addition, an erroneous signal caused by higher-order reflected electrons or the like hinders improvement in image processing accuracy and positional accuracy, thereby slowing progress in miniaturization of element dimensions.

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 a diffraction grating to scatter reflected electrons. ing. 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 higher-order backscattered electrons of the third order and higher are not necessarily reduced. Since there is no such effect, a great effect cannot be expected in reducing false signals.

For the purpose of reducing the long-range photosensitizing effect, for example, as described in Japanese Patent Application Laid-Open No. 61-19126, irregularities are provided on the opposing wall surface of a sample to scatter reflected electrons, thereby making the secondary electrons secondary. A method has been proposed for preventing reflected electrons from re-entering the sample. In this way,
Secondary reflected electrons from the opposing wall of the sample are reduced,
Higher-order reflected electrons scattered by the unevenness cannot scatter above the opposing wall surface, and eventually return to the sample from the opposing wall surface, so that a large effect in reducing high-order reflected electrons and the like cannot be expected.

For the purpose of reducing the long-distance photosensitive action and the beam drift, for example, Japanese Patent Application Laid-Open No. 2000-2000
As described in Japanese Patent No. 2960413, an antireflection mechanism having an oblique honeycomb opening structure is disposed between the sample and a structure above the sample, and the reflected electrons are re-incident on the sample as secondary reflected electrons. There have been proposed methods to prevent this. 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 higher-order or higher-order backscattered electrons caused by the backscattered electrons.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention 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.

Further, there is provided a semiconductor integrated circuit device which is processed, observed, and inspected stably and with high precision by reducing erroneous signals of the electron detection device and has a finer element size, and a method of processing, observing and inspecting the same. The purpose is to do.

[0008]

According to an embodiment of the present invention, there is provided a detector for detecting electrons and a holder for holding the detector, and a charged particle beam is irradiated on the sample to reflect reflected electrons or electrons from the sample. When detecting the next electron, the holder is constituted by a plurality of cylinders having a spatula. 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 to selectively introduce 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 is provided 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 electrons or higher-order secondary electrons, selectively use reflected or secondary electrons outside the sampling angle range. The tube provided with the spatula portion for capturing at the above is disposed inside and outside the tube provided with the spatula portion at an angle at which the reflected electrons or the secondary electrons within the sampling angle range are selectively introduced into the detector. Even if the reflected electrons or secondary electrons hitting the end 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 resulting from the high-order secondary electrons is reduced, and the detection accuracy of the reflected electrons or the secondary electrons can be improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 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, and FIG. 2 is a longitudinal sectional view showing the structure of an electron detecting apparatus in the prior art. ,
FIG. 3 is a longitudinal sectional view showing the structure of the electron detecting device according to the first embodiment 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.

In the electron beam writing apparatus shown in FIG. 1, an electron beam 17 emitted from an electron gun 1 is shaped into a circle by a stop 2, radiated on a stop 5, and formed on a stop 8 by a lens 9. Is done. 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 aperture 8 is
It is selected by the deflector 7. The drawing is performed by moving the stage 19 in an area other than the area deflected by the deflector 13. The reflected electrons 29 from the mark 28 arranged 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.

As shown in FIG. 2, in the shape of the holder 30 using the conventional technique, the reflected electrons 3 hit the holder surface other than the opening 33 for introducing the reflected electrons 31 and the like into the detector 32.
Higher-order backscattered electrons 35, 36 and the like by 4 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. In addition, a higher-order backscattered electron 38 due to a backscattered electron 37 hitting the bottom of the holder may affect the sample 39.

The means for solving this problem in the present invention will be described below. Here, as shown in FIG. 3, the holder is constituted by a plurality of cylinders 41, 42, 43, 44 having a spatula. Spatula squeezing section 4 in desired sampling angle range 45
The detector 49 is arranged between the cylinders 42 and 43 having 6 and 47. Spatula narrowing portions 46 of cylinders 42 and 43 sandwiching detector 49,
47 selectively introduces 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 or the like. Higher order backscattered electrons 56, 57, 58, etc. due to the backscattered electrons 54, 55, etc. hitting the tip are also captured and prevented from being introduced into the detector 49. Further, 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. Tubes 41, 42, 43, 44
Alternatively, the positional relationship between the tips of the spatula portions 46, 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 the cylinder 41 is a straight line with the innermost cylinder 41 being axially symmetric. The tip of the spatula section 46 of the inner cylinder 42 sandwiching the detector 49 is arranged on 62, and the tip of the spatula section 47 of the outer cylinder 43 sandwiching the detector 49 and the outside of the sampling angle range 45. The straight line 63 connecting the tip of the spatula section 48 is parallel to the sample 50. This makes it possible to reduce erroneous signals due to higher-order reflected electrons and the like. (Embodiment 2) FIG. 4 is a longitudinal sectional view showing the structure of an electron detecting device according to a 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 has a plurality of cylinders 66, 67,
68 and 69. Desired sampling angle range 70
The detector 74 is arranged between the cylinders 67 and 68 having the spatula diaphragm parts 71 and 72. The spatula diaphragm 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. Sampling angle range 70
The outer tube 66 or the spatula 73 captures the reflected electrons 77 and 78 flying from the sample 75 so as not to become higher-order reflected electrons, and hits the tip of the tube 66 or the spatula 73. Higher order backscattered electrons 80 and the like due to the backscattered electrons 79 are also captured, and are prevented from being introduced into the detector 74. Further, the reflected electrons 81 flying outside the spatula 73 of the outermost cylinder 69 do not hit the spatula, so they do not become higher-order reflected electrons and the like, and the sample 75
There is no influence by entering the light. Cylinders 66, 67, 68,
The positional relationship between the tips of the spatula parts 69, 72, and 73 is determined by the detector
The tip of the spatula 71 of the inner cylinder 67 sandwiching the detector 4 is disposed, and the tip of the spatula 72 of the outer cylinder 68 sandwiching the detector 74 and the spatula 7 outside the sampling angle range 70.
A straight line 83 connecting the tips of 3 is parallel to the sample 75. This makes it possible to reduce erroneous signals due to higher-order reflected electrons and the like. (Embodiment 3) Although the above embodiment has shown an electron beam drawing 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, regarding the ion beam, the lens, aperture, and other mechanisms have the same functions as those of the electron beam device. (Embodiment 4) A manufacturing process of a semiconductor integrated circuit using an electron beam drawing method using an electron beam drawing apparatus provided with an electron detection device of the present invention will be described.

[0013] An N-silicon substrate is subjected to P
Well layer, P layer, field oxide film, polycrystalline silicon /
A silicon oxide film gate, a P high concentration diffusion layer, an N high concentration diffusion layer, and the like are formed. Next, an insulating film of phosphorus glass (PSG) is applied, and the insulating film is dry-etched to form a contact hole.

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.

Next, an interlayer insulating film was formed, and a hole pattern was formed by an ordinary 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.

Although only the main manufacturing steps have been described in the present embodiment, the same steps as those in the conventional method were used except that the electron beam drawing method of the present invention was used in the lithography step for forming the W / TiN electrode wiring. . Through the above steps, a fine pattern can be formed without deteriorating the quality.
SLSI could be manufactured with high yield. As a result of manufacturing a semiconductor integrated circuit using the electron beam writing apparatus of the present invention, the yield was improved due to the improved mark detection accuracy, and the production amount could be increased.

[0017]

As described above, according to the present invention, it is possible to reduce an erroneous signal caused by higher-order reflected electrons and higher-order secondary electrons that lower the detection accuracy of reflected electrons and the like.

Further, there is provided a semiconductor integrated circuit device which is processed, observed and inspected stably and with high precision by reducing erroneous signals of the electron detecting device and has a finer element size, and a method of processing, observing and inspecting the same. can do.

[Brief description of the drawings]

FIG. 1 is a schematic vertical 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 a 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 the 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
... marks, 29, 31, 34, 37, 51, 52, 5
3,54,55,64,76,77,78,79,81
... reflection electrons, 33 ... apertures, 35, 38, 56, 58, 8
0: secondary reflected electrons, 36, 57: tertiary reflected electrons, 41,
42, 43, 44, 66, 67, 68, 69 ... cylinder, 45
... Sampling angle range, 46, 47, 48, 71, 72, 73
... Spatula diaphragm, 59. Locus, 60. Angle.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ryoyo Asai 882, Omo, Oita, Hitachinaka-shi, Ibaraki F-term within the Hitachi Measuring Instruments Group (Reference) 2G001 AA03 BA07 BA15 CA03 DA03 GA06 JA06 LA11 MA05 SA01 SA30 2H097 CA16 LA10 5C033 NN01 NN02 NP01 NP08 5F056 BB01 BB10 EA18

Claims (4)

[Claims] An electron detection device comprising a detector for detecting electrons and a holder for holding the detector, wherein a charged particle beam is irradiated on a sample to detect reflected electrons or secondary electrons from the sample. The holder is composed of a plurality of cylinders having a spatula section, and 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 of the spatula diaphragm section 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,
An electron detection apparatus, comprising: a cylinder having a spatula section for selectively capturing reflected electrons or secondary electrons outside the collection angle range in the spatula section. 2. 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, irradiating the charged particle beam onto a sample, and reflecting electrons or secondary electrons from the sample. Equipped with an electronic detection device for detecting electrons,
In a charged particle beam apparatus for observing, processing, or drawing the sample, the charged particle beam apparatus includes a detector for detecting electrons and a holder for holding the detector, and the holder is configured by a plurality of cylinders having a spatula. , The spatula aperture crosses the intersection of the center line of the charged particle beam and the sample,
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 respect to the central axis, and is outside the sampling angle range. A charged particle beam apparatus comprising: a cylinder having a spatula section for selectively capturing reflected electrons or secondary electrons. 3. A device comprising: a detector for detecting electrons; and a holder for holding the detector, wherein the holder is constituted by a plurality of cylinders having a spatula portion, and the spatula portion has an extended line having the charged particles. The tube intersects the intersection of the central axis of the beam and the sample, and has a spatula for selectively introducing reflected electrons or secondary electrons within the sampling angle range with respect to the central axis. A detector is disposed, the electrons are irradiated and processed by a charged particle beam apparatus having a cylinder provided with a spatula section that selectively captures reflected electrons or secondary electrons that are outside the collection angle range, and generated. A semiconductor integrated circuit device characterized in that reflected electrons or secondary electrons are detected, observed, or inspected. 4. A device comprising: a detector for detecting electrons; and a holder for holding the detector, wherein the holder is composed of a plurality of cylinders having a spatula, and the spatula is extended by the charged particles. The tube intersects the intersection of the central axis of the beam and the sample, and has a spatula for selectively introducing reflected electrons or secondary electrons within the sampling angle range with respect to the central axis. A detector is disposed, the electrons are irradiated and processed by a charged particle beam apparatus having a cylinder provided with a spatula section that selectively captures reflected electrons or secondary electrons that are outside the collection angle range, and generated. A method of processing, observing, and inspecting a semiconductor integrated circuit device, wherein reflected or secondary electrons are detected and observed or inspected.