JP2002208373A - Signal detecting method and device for electron beam device and manufacturing method of such device using above electron beam device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal detecting method and device for an electron beam device which does away with a hermetic seal and yet suffers from no distortion of image with FOP. SOLUTION: With the signal detecting device for an electron beam device in which, an electron beam 11 from a surface of a sample is put into an MCP, and made collided with a fluorescent material layer equipped at an end face of an FOP arranged in the vicinity of the MCP to have it emit a light signal, which is transferred to either a CCD sensor or a CCD-TDI sensor through the FOP, MCP and either the CCD sensor or the CCD-TDI sensor are to be put under different pressure states.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a signal in an electron beam apparatus, a defect inspection apparatus using such an electron beam apparatus, and a method for manufacturing a device using such an electron beam apparatus. More specifically, a device that constitutes a signal detection device in an electron beam apparatus suitable for performing defect inspection, line width measurement, defect review, or pattern potential measurement of a sample having a pattern with a minimum line width of 0.1 μm or less. A signal detection method, a signal detection device, a defect inspection device using such an electron beam device, and a device manufacturing method using such an electron beam device.

[0002]

2. Description of the Related Art An electron beam apparatus for performing defect inspection, line width measurement, defect review or pattern potential measurement of a sample includes a primary electron optical system (hereinafter simply referred to as a primary optical system) for irradiating the sample with an electron beam. A secondary electron optical system (hereinafter simply referred to as a secondary optical system) for extracting secondary electrons emitted from a sample, and a signal detection device that converts an electronic signal sent by the secondary optical system into an optical signal and detects the optical signal There is. This signal detection device includes:
Conventionally, generally, MCP (micro channel plate) and FOP (fiber optical plate)
And CCD (Charge Coupled Device) or TDI-
A CCD (time delay and integration-charge coupled device) is used. In such a conventional signal detection device, MCP, FOP and CCD
Alternatively, the TDI-CCD is housed in a vacuum chamber,
Alternatively, an optical signal sent from the TDI-CCD is led out of the vacuum chamber through a conductor sealed by a hermetic seal.

[0003]

By the way, in the conventional signal detecting device as described above, a CCD or a TDI-CCD is used.
The number of conductors for transmitting optical signals coming out of the line is very large, about 100 lines. In order to inspect a sample with high throughput, each conductor needs to handle a high-frequency signal of about 800 MHz. There is no real hermetic seal that can transmit a signal at 800 MHz without crosstalk through a conductor.

One problem that the present invention seeks to solve is:
An object of the present invention is to provide a signal detection method and apparatus in an electron beam apparatus that does not require a hermetic seal and does not distort an image due to FOP. Another object of the present invention is to provide a signal detection method and apparatus in an electron beam apparatus in which an MCP and a CCD or a TDI-CCD are arranged in different chambers and the chambers are set to different pressure states. is there. Another problem that the present invention seeks to solve is:
A signal detection device in an electron beam device in which an MCP and a CCD or a TDI-CCD are disposed in different chambers, and a FOP disposed between the MCP and the CCD or the TDI-CCD is sealed and fixed to a partition wall between the two chambers. To provide. Still another problem to be solved by the present invention is to provide a defect inspection using such an electron beam device. Still another object to be solved by the present invention is to provide a method for manufacturing a device for evaluating a sample during a process using the electron beam apparatus as described above.

[0005]

According to one aspect of the present invention, an electron beam from a sample surface is made incident on an MCP, and a fluorescent material layer provided on an end face of an FOP disposed adjacent to the MCP is formed on the fluorescent material layer. An optical signal is generated by colliding an electron beam, and the optical signal is transmitted through the FOP to a CCD sensor and a CCD-T.
In a signal detection method in an electron beam device for transmitting to any one of DI sensors, the MCP and one of a CCD sensor and a CCD-TDI sensor are placed under different pressure conditions. In one aspect of the signal detection device for an electron beam device according to the present invention, the different pressure states may be different negative pressure states.

Another invention of the present application is a MCP, a FOP,
Having one of a CCD and a TDI-CCD, causing electrons from the sample surface to collide with the fluorescent material layer provided on the end face of the FOP via the MCP to generate a light signal, and generating the light signal. In the signal detecting device in the electron beam device for transmitting to the one of the CCD sensor and the CCD-TDI sensor through the FOP, the MCP and one of the CCD and the TDI-CCD are separated from each other via a partition. The MCP is disposed in different chambers, the chamber in which the MCP is disposed is sealed with the outside, and the FOP is sealed and fixed to the partition. In one aspect of the signal detection device for an electron beam device according to the present invention, the different chambers may be in different pressure states.

Another invention of the present application relates to a primary optical system having an E × B separator for deflecting an electron beam by the E × B separator and irradiating the sample with the electron beam, and a secondary optical system for recovering electrons from the sample. A secondary optical system, and a signal detection device for detecting electrons recovered by the secondary optical system, wherein the signal detection device includes an MCP, a FOP
And any one of a CCD and a TDI-CCD, and transfers electrons from the sample surface to the FO through the MCP.
In a surface inspection apparatus for generating an optical signal by colliding with a fluorescent material layer provided on an end face of P and transmitting the optical signal to one of a CCD sensor and a CCD-TDI sensor through the FOP, the MCP and the CCD And TD
One of the I-CCDs is placed in different chambers separated from each other by a partition, and the MC
The chamber in which P is disposed is sealed from the outside, the image plane of the secondary electrons is made coincident with the deflection center of the E × B separator when inspecting the surface of the sample, and the image plane of the primary electrons is set to the E × B The electron source is located closer to the electron source than the center of deflection of the separator. Another invention of the present application is a device manufacturing method for inspecting a pattern of a device in the middle of a process using the electron beam apparatus.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a signal detecting device for an electron beam device according to the present invention will be described below with reference to the drawings. FIG. 1 schematically shows an electron beam device 1 including a signal detection device according to the present embodiment. The electron beam apparatus 1 includes a primary electron optical system (hereinafter simply referred to as a primary optical system) 1
0, a secondary electron optical system (hereinafter simply a secondary optical system) 20,
A signal detection device 30. Primary optical system 10
Is an electron optical system that irradiates an electron beam onto a surface of an inspection target (hereinafter, a sample) S, and includes an electron gun 11 that emits an electron beam, and an electrostatic lens 12 that deflects a primary electron beam E1 emitted from the electron gun 11. And 13 and an E × B separator 14 for deflecting the primary electron beam so that its optical axis is perpendicular to the plane of interest.
And electrostatic lenses 15 and 16 for deflecting the electron beam, which are arranged in order with the electron gun 11 at the top as shown in FIG. 1, and furthermore, for the primary electron beam E1 emitted from the electron gun. The optical axis is arranged to be inclined with respect to a line perpendicular to the surface of the sample S (sample surface). The E × B separator 14 is the electrode 1
41 and a magnet 142.

The secondary optical system 20 includes electrostatic lenses 21 and 22 disposed above the primary optical system E × B separator 14. The primary optics and the secondary optics are arranged in a closed chamber defined by a housing (not shown), and the chamber is evacuated by a known method. (It is a so-called vacuum, not an absolute vacuum). As shown in FIG. 2, the signal detection device 30 includes an MCP (micro channel plate) 31, an FOP (fiber optical plate) 32, a CCD (charge coupled device) or a TDI-CCD (time delay and integration-charge). Coupled device) 33. The MCP 31 is located in a chamber 41 which may be common or separate from the chamber in which the secondary optics is housed. CCD or T
The DI-CCD 33 is disposed in another chamber 42 separated from the chamber 41 by a partition 43. M
The FOP 32 disposed between the CP 31 and the CCD or the TDI-CCD 33 includes a through-opening 4 formed in the partition 43.
4. The FOP 32 is joined and fixed to the inner surface of the through opening 44 by a vacuum adhesive 45 applied to the outer periphery. Thereby, the airtightness between the chambers 41 and 42 is maintained. This eliminates the need for a multi-pin high frequency hermetic seal, which is conventionally required, and eliminates the need to worry about signal degradation due to crosstalk between pins. The end face of the FOP 32 facing the MCP 31 is provided with a fluorescent material layer, that is, a scintillator 34. Therefore, the fluorescent material layer 34 is exposed to the pressure atmosphere of the chamber 41. CCD or TDI
The CCD 33 is connected to a signal processing circuit 38 via a socket 35 and a number of conductors 36; In this embodiment, the inside of the chamber 41 is maintained in a vacuum state,
Inside is kept at atmospheric pressure.

Next, the operation of the electron beam apparatus 1 having the above configuration will be described. The primary electron beam E1 emitted from the electron gun 11 reaches the E × B separator 14 via the electrostatic lenses 12 and 13 of the primary optical system 10, and the E × B separator 14 causes the E × B separator 14 to move the electron beam to the surface of the sample S. The light is deflected so as to be vertical, and is further irradiated on the surface (sample surface) SF of the sample S via the electrostatic lenses 15 and 16. Secondary electrons E2 are emitted from the sample surface SF according to the properties of the sample. The secondary electrons E2 are converged by the electrostatic lenses 15 and 16 and are imaged substantially at the center of the E × B separator 14. However, the primary electrons passing through the lenses 15 and 16 have the energy of (20 KV + 500 V), and the secondary electrons have the energy of (20 KV + the initial energy of the secondary electron). Since it is impossible to focus these two energy electron beams on the same surface, secondary electrons are given priority in this embodiment. The secondary electrons E2 are further transmitted to the MC of the signal detection device 30 through the electrostatic lenses 21 and 22 of the secondary optical system 20.
It is incident on one end face (lower face in FIG. 2) of P31. MCP
Is multiplied there while retaining image information, emitted from the opposite end face (upper surface in FIG. 2) and irradiated to the fluorescent material layer, that is, the scintillator 34. An optical signal corresponding to the electron intensity is generated. That is, the secondary electrons are converted into an optical signal by the fluorescent material layer. The optical signal is sent to the CCD or TDI-CCD 33 via the FOP 32 and is converted into an electric signal there. The converted electric signal is sent to a signal processing circuit 38 provided outside via a number of conductors 36 and processed by the processing circuit.

The signal processing circuit compares the processed signal with reference data relating to a designed pattern stored in a storage unit by, for example, a comparison circuit (not shown) to determine whether a pattern formed on the sample has a defect or not. Defect inspection can be performed by using a defect detection circuit for detecting a position. Further, when the signal processing circuit is a line width measuring circuit, the line width of the pattern formed on the sample surface can be measured. Further, if a CRT monitor is further connected to the signal processing device, the defect can be reviewed. Furthermore, if a function of blanking a beam is provided somewhere in the primary optical system, it can be used as an EB tester. In addition,
When the inside of the chamber 41 is evacuated and the inside of the chamber 42 is set to the atmospheric pressure, the pressure difference is too large and the FOP is distorted. As a result, the image may be distorted while the signal passes through the FOP.
In this case, the pressure difference applied to the FOP may be reduced by setting the inside of the chamber 42 to a negative pressure state lower than the atmospheric pressure. Further, in the description of the above embodiment, the electrons detected by the signal detection device 30 are described as the secondary electrons emitted from the sample by irradiating the sample with the primary electrons. You may.

Referring to FIG. 3, another embodiment 30a of the signal detection device is shown. In this embodiment, 43
a is a partition separating the chambers 41a and 42a in an airtight state. Not only is the chamber 41a sealed from the atmosphere as in the above-described embodiment, but also the chamber 42a is
CD camera or TDICCD camera 39a or C
It is sealed by a D mount or TDI-CCD mount 49a. In the stepped opening 44a formed in the partition 43a, a stepped first FOP 32a1 (having different diameters in the upper portion and the lower portion in FIG. 3) is also arranged. The surface and the outer peripheral surface of the FOP are joined and fixed by silver brazing or fusion 45a.
Therefore, gas is prevented from flowing between the chambers 41a and 42a through the opening. A second FOP 32a2 and a CCD sensor or TDI-
The CCD sensor 33a is arranged with the second FOP 32a2 on the first FOP 32a1 side. Further, the chambers 41a and 42a are connected to a vacuuming device (not shown) such as a vacuum pump via an exhaust pipe 51a, so that a vacuum state or a negative pressure (relative to the atmospheric pressure) is established. ing. The exhaust pipe 51a has a chamber 41a.
An adjustable throttle 54a is provided between a connection port 52a to the chamber 42a and a connection port 53a to the chamber 42a. In addition,
31a is an MCP, and 34a is a fluorescent material layer, that is, a scintillator.

In the case of the above embodiment, MCP, FOP, F
When DI, CCD, etc. are not operating, stop the diaphragm 54a.
Fully open the first and second chambers in the same high vacuum state (example
For example, 1 × 10^-8(torr). On the other hand, MC
When P, FOP, FDI, CCD, etc. are operating,
The exhaust gas from the chamber 42a is adjusted by adjusting the throttle 54a.
It is prevented from flowing into the chamber 41a. For example,
Pressure P in chamber 41a ₁Is 1 × 10^-7torr,
Pressure P in chamber 42a_TwoIs 1 × 10^-3torr
You.

Next, an embodiment of a method for manufacturing a semiconductor device according to the present invention will be described with reference to FIGS. FIG.
3 is a flowchart showing one embodiment of a method for manufacturing a semiconductor device according to the present invention. The manufacturing process of this embodiment includes the following main processes. (1) Wafer manufacturing process for manufacturing a wafer (or wafer preparing process for preparing a wafer) (2) Mask manufacturing process for manufacturing a mask used for exposure (or mask preparing process for preparing a mask) (3) Necessary for wafer (4) Chip assembling step of cutting out chips formed on a wafer one by one and making them operable (5) Chip inspection step of inspecting the resulting chips The main process further comprises several sub-processes.

Among these main steps, the wafer processing step (3) has a decisive effect on the performance of the semiconductor device. In this step, designed circuit patterns are sequentially stacked on a wafer, and a number of chips that operate as memories and MPUs are formed. This wafer processing step includes the following steps. (A) A thin film forming step (CVD) for forming a dielectric thin film serving as an insulating layer, a wiring portion, or a metal thin film forming an electrode portion.
(B) Oxidation step of oxidizing this thin film layer or wafer substrate (C) Lithography for forming a resist pattern using a mask (reticle) to selectively process the thin film layer or wafer substrate Step (D) An etching step of processing a thin film layer or a substrate according to a resist pattern (for example, using a dry etching technique) (E) Ion / impurity implantation / diffusion step (F) Resist stripping step (G) Further, the processed wafer is inspected Step of Performing The wafer processing step is repeated by the required number of layers to manufacture a semiconductor device that operates as designed.

FIG. 5 is a flowchart showing a lithography step which is the core of the wafer processing step shown in FIG. This lithography step includes the following steps. (A) a resist coating step of coating a resist on a wafer on which a circuit pattern has been formed in the preceding step (b) an exposure step of exposing the resist (c) a developing step of developing the exposed resist to obtain a resist pattern (D) Annealing Step for Stabilizing the Developed Resist Pattern The above-described semiconductor device manufacturing step, wafer processing step, and lithography step are well known and need no further explanation. When the defect inspection method and the defect inspection apparatus using the electron beam apparatus according to the present invention are used in the inspection step (G), even a semiconductor device having a fine pattern can be inspected with a high throughput, so that 100% inspection can be performed. It is possible to improve the product yield and prevent the shipment of defective products. Further, according to the line width measuring method and apparatus using an electron beam apparatus, the line width of a pattern formed on a sample surface can be measured with high accuracy and high throughput. Further, according to the defect review method and apparatus using the electron beam device, the defect can be monitored with high accuracy.

[0017]

According to the present invention, the following effects can be obtained. (A) A high frequency hermetic seal with multiple pins, which has been required conventionally, is no longer necessary, and there is no need to worry about signal degradation due to crosstalk between pins. . (B) Since the pressure of one hectopascal is not applied to the FOP, there is no image distortion. (C) Since the image plane of the secondary electrons coincides with the deflection center of the E × B separator, secondary electrons having different energy widths can be imaged with less aberration. (D) the energy width of the primary electron beam is finite,
There is no particular problem caused by the difference between the deflection center of the E × B separator and the image position of the primary electron beam.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of an electron beam device provided with a signal detection device according to the present invention.

FIG. 2 is a diagram showing one embodiment of a signal detection device of the electron beam device of FIG. 1;

FIG. 3 is a diagram showing another embodiment of the signal detection device.

FIG. 4 is a flowchart showing one embodiment of a method for manufacturing a semiconductor device according to the present invention.

FIG. 5 is a flowchart showing a lithography step which is a core of the wafer processing step shown in FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electron beam apparatus 10 Primary optical system 11 Electron gun 12, 13 Electrostatic lens 14 ExB separator 15, 16 Electrostatic lens 20 Secondary optical system 21, 22 Electrostatic lens 30, 30a Signal detection apparatus 31, 31a
MCP 32, 32a1, 32a2 FOP 33, 33a CCD or TDI-CCD 34, 34a Fluorescent material layer 41, 41a, 42, 42a Chamber 43, 43a Partition wall 51a Exhaust pipe 54a Aperture

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 37/28 H01J 37/28 B H01L 21/66 H01L 21/66 J // G01R 31/02 G01R 31 / 02 (72) Inventor Masanori Hatakeyama 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation (72) Inventor Mamoru Nakasuji 11-1 Asahi-cho Haneda, Ota-ku, Tokyo Inside Ebara Meister Co., Ltd. (72 Inventor Shinji Noji 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Works, Ltd. (72) Inventor Toru Satake 11-1, Haneda Asahi-cho, Ota-ku, Tokyo Inside Ebara Works, Ltd. Takeshi F-term (reference) 2F067 AA26 AA62 BB01 BB04 CC17 HH06 HH13 JJ01 JJ05 KK04 LL16 2G001 AA03 BA07 CA01 DA01 DA09 GA01 GA06 HA12 HA13 JA02 JA03 JA14 KA03 LA11 MA05 RA04 RA08 2G014 AA01 AB59 AC11 4M106 AA01 CA39 DB04 DB05 5C033 NN01 NP02 NP05 NP08 UU02 UU04

Claims (6)

[Claims] 1. An electron beam from a sample surface is incident on an MCP, and the electron beam is caused to collide with a fluorescent material layer provided on an end face of an FOP disposed adjacent to the MCP to generate a light signal. And transmitting the optical signal to one of a CCD sensor and a CCD-TDI sensor through the FOP.
A signal detection method in an electron beam device, wherein a CP and one of a CCD sensor and a CCD-TDI sensor are placed under different pressure states. 2. The signal detecting method according to claim 1, wherein the different pressure states are different negative pressure states. 3. MCP, FOP, CCD and TDI
A light signal is generated by colliding electrons from the sample surface with the fluorescent material layer provided on the end face of the FOP through the MCP, and the light signal is transmitted through the FOP. In a signal detection device in an electron beam device for transmitting to either one of a CCD sensor and a CCD-TDI sensor, the MCP, the CCD and the TDI
Placing one of the CCDs in different chambers separated from each other by a partition,
The chamber in which is placed is hermetically sealed from the outside,
A signal detecting device in an electron beam device, wherein P is sealed and fixed to the partition. 4. The signal detecting device according to claim 3, wherein the different chambers are in different pressure states. 5. An electron beam splitter having an E × B separator for exchanging an electron beam
A primary optical system for irradiating the sample with deflection by the B separator, a secondary optical system for collecting electrons from the sample, and a signal detecting device for detecting electrons collected by the secondary optical system, The signal detection device is composed of MCP, FOP, CCD and TD
An I-CCD, an electron from the sample surface is made to collide with the fluorescent material layer provided on the end face of the FOP via the MCP to generate a light signal, and the light signal is generated by the FOP. Through CCD sensor and CCD-TDI
In the surface inspection apparatus for transmitting to any one of the sensors, the MCP and one of the CCD and the TDI-CCD are respectively disposed in different chambers separated from each other via a partition, and the MCP is disposed. The chamber is sealed from the outside, and the image plane of the secondary electrons is made coincident with the deflection center of the E × B separator when inspecting the surface of the sample, and the image plane of the primary electrons is set at the deflection center of the E × B separator. A surface inspection apparatus characterized in that it is closer to the electron source. 6. A method for manufacturing a device, comprising: inspecting a pattern of a device during a process using the method or the apparatus according to claim 1.