JP2002341216A - Optical element assembly for electron-beam device, treating method for the same optical element assembly, and device manufacturing method using electron-beam device equipped with the same optical element assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element assembly which can actualize high-level mutual positioning precision for a plurality of optical elements with simple constitution. SOLUTION: The optical element assembly 1 is equipped with a plurality of lenses 31, 33, and 35, a cylinder body 10 which stores the lenses 31, 33, and 35 inside, and holders 20A, 20B, and 20C which are fitted to the cylinder body and arranged coaxially with the center axis of the cylinder body at equal intervals on the same circumference and hold the respective lenses in a position- adjustable state. This optical element assembly is manufactured as a unit and built integrally in a lens barrel which carries the optical system of an electron- beam device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element assembly for holding a lens, an aperture member, a deflector and the like (hereinafter referred to as an optical element) in an electron optical system of an electron beam apparatus. The present invention relates to an optical element assembly capable of holding an optical element of an electron optical system disposed in an apparatus with high positioning accuracy, and a method of processing such an optical element assembly. The present invention also relates to a device manufacturing method for evaluating an in-process wafer using an electron beam apparatus having such an optical element assembly.

[0002]

2. Description of the Related Art An electron beam apparatus includes an electron gun for emitting an electron beam,
A primary electron optical system composed of optical elements for focusing an electron beam from an electron gun and irradiating the sample, a secondary electron optical system for causing secondary electrons from the sample to enter a detector, and detecting secondary electrons Conventionally, the optical element is individually processed into a cylindrical part which has been processed with high precision roundness and coaxiality and which has been processed with high precision fitting tolerance. As a result, high positioning accuracy between these optical elements has been obtained. On the other hand, as the objects to be evaluated have been highly miniaturized in recent years, an electron beam apparatus having an increasingly higher detection accuracy has been required. Therefore, extremely high positioning accuracy between the optical elements provided in the electron beam apparatus is required. However, in the method relying on the processing accuracy as described above, it is difficult to achieve the required accuracy with the current machining accuracy, and if the fitting tolerance is strict, a cylindrical member can be formed even with a slight processing error. There are problems such as difficulty in assembling the optical element into the optical element or removing the optical element from the cylindrical member. Apart from the above method, a method is also conceivable in which the fitting tolerance between the cylindrical member and the optical element is loosened to enable positioning adjustment in the radial direction during assembly, but such adjustment requires time and effort. It is inefficient and doing it on individual optical elements requires a lot of effort and time. It is also difficult to reproduce the accuracy before disassembly at the time of reassembly after disassembly.

[0003]

One object of the present invention is to provide an electron beam apparatus capable of realizing a high degree of positioning accuracy between a plurality of optical elements of an electron optical system with a simple configuration. An optical element assembly is provided. Another problem to be solved by the present invention is that an optical element assembly for an electron beam apparatus that can easily reproduce high positioning accuracy before disassembly even when the optical element assembly is disassembled and reassembled after cleaning. It is to provide. Another problem to be solved by the present invention is to provide a method for manufacturing an optical element assembly as described above. It is still another object of the present invention to provide a method for evaluating a wafer using an electron beam apparatus having the above-described optical element assembly.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, one of the inventions of the present application is an optical element assembly capable of setting an optical element to an electron beam device with high positioning accuracy.
A cylindrical body capable of accommodating the plurality of optical elements therein, having a flange portion having an outer peripheral edge on the same circumference centered on the center axis of the cylindrical body at one end, and A cylinder adapted to be detachably attached to a predetermined position, and the plurality of optical elements housed in the cylinder,
A plurality of sets of retainers attached to the cylindrical body at equal intervals in a circumferential direction, the retainers having a tip that can protrude radially inward from an inner peripheral surface of the cylindrical body, and the optical tip at the tip. A plurality of sets of holders for holding the elements so as to be position-adjustable are provided in combination, so that the optical elements can be machined while holding the optical elements in the cylinder. With such a configuration, it is possible to realize a high positioning accuracy between the optical elements with a simple configuration by using the cylinder and the plurality of optical elements as one unit. In another aspect of the invention of an optical element assembly, in order to reproduce the optical elements in the same phase with each other when disassembling and reassembling the optical element assembly, the cylindrical body and each optical element are provided. Is marked. By providing the matching mark in this manner, a high positioning accuracy before disassembly can be easily reproduced even when reassembling the optical element assembly.

According to another aspect of the present invention, there is provided a method of processing an optical element assembly for an electron beam apparatus, comprising the steps of: (1) preparing a cylinder accommodating a plurality of optical elements and holding a plurality of cylinders on the cylinder; Mounting a vessel, (2) inserting a spacer and an unprocessed optical element into the cylindrical body, and holding the optical element by the plurality of sets of holders, and (3) the plurality of optical elements. Setting the cylinder holding the element in a processing machine, and processing the cylinder and a plurality of optical elements in order,
(4) After processing is completed, the cylinder is removed from the processing machine to perform post-processing; and (5) The optical element is removed from the cylinder removed from the processing machine and post-processed to the cylinder and the optical element. And (6) positioning and fixing the optical element after the post-processing in the cylinder after the post-processing by the retainer. Thus, after assembling a plurality of optical elements integrally with the cylinder, by processing these cylinders and the plurality of optical elements, the cylinder and the plurality of optical elements are formed as one unit so that each optical element can be mutually connected. High positioning accuracy can be realized by a simple method. In another aspect of the invention of a processing method, the step of inserting the optical element into the cylindrical body and holding the optical element by a holder includes a step of attaching a matching mark to the cylindrical body and the optical element. The provision of the matching mark in this manner makes it possible to easily reproduce high positioning accuracy before disassembly at the time of reassembly of the optical element assembly.

[0006] Still another invention of the present application is to evaluate a wafer during a process by using an electron beam apparatus provided with the above-described optical element assembly.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The invention of the present application will be described. FIG. 1 is a plan view partially showing a cylindrical body 10 and a retainer 20 in the optical element assembly 1 of the present invention, and FIG. 2 is an enlarged sectional view showing an attached state of the retainer. FIG. 3 is a cross-sectional view of the optical element assembly taken along line GG in FIG. 1 showing a state before drilling, in which a plurality of optical elements, for example, a lens, an aperture member, a deflector, and the like are assembled to the cylinder 10. It is. In the following, for convenience of description, a case will be described in which only a plurality of lenses are assembled to the cylindrical body 10. FIG. 4 is a cross-sectional view showing the completed optical element assembly after the lens and the cylinder are drilled in the state of FIG. As shown in FIG. 4, the optical element assembly 1 is attached as a unit to a lens barrel (not shown) that houses an electron optical system of an electron beam apparatus. In each of the drawings, a mechanism for applying a charge to the lens is omitted.

1, 2, and 4, an optical element assembly 1 includes a cylindrical body 10, a plurality of (in this embodiment, three by way of example) holders 20A, 20B, 20C, and a plurality of ( In the embodiment, three (for example, three) lenses 31, 33, and 35 are included. The cylindrical body 10 has a cylindrical shape as a whole, and has an upper flange 101, a lower flange 102, and a main body portion 103. The upper flange 101 and the lower flange 102 are used to fix the optical element assembly 1, which is a unit formed by integrally attaching a plurality of lenses to the cylinder 10 to a drilling machine, with a chuck, as will be described later. It is used to attach the assembly to the electron beam column. The retainer 20A, 2
OB and 20C are mounted coaxially with the central axis of the cylindrical body 10 and on the same circumference at equal intervals. Cage 20
A, 20B and 20C all have the same shape,
A, 202B, 202C, cylindrical or rectangular projections 203A, 203B, 203C and mounting bolts 20
1A, 201B and 201C. Each base 202
A, 202B, 202C have bolts 201A, 201
B, through holes 205A, 205B for passing 201C,
205C are provided two by two. Each protrusion 203
A, 203B, and 203C hold the lens so that the lens can be positioned and adjusted in a state where the peripheral edges of the lens are in contact with their tips 204A, 204B, and 204C, as described later.

The main body 103 further includes a retainer 20.
A, 20B, 20C Base 202A, 202B, 202
Flat surfaces 104A, 104B, 1 on which C respectively sits
04C are formed at equal intervals in a form coaxial with the central axis of the cylinder 10 and in contact with the same circumference. Further, through-holes 106A, 106B, 106C into which the protrusions 203A, 203B, 203C of the respective retainers are fitted are formed on each of the flat surfaces 104A, 104B, 104C, and on both sides of the through-holes. Bolts 201A, 201B,
Screw holes 107A, 107B,
107C is formed. Flat surfaces 104B and 10
The thicknesses Tb and Tc of 4C correspond to the tip 204B of the retainer 20B.
And each of the tips 204C of the retainers 20C is
Is slightly machined (for example, 1 mm in the present embodiment) from the surface of the inner wall 105. This is because the outer diameters of the lenses 31, 33, and 35 are processed to be smaller than the inner diameter of the inner wall 105 of the cylindrical body 10 by about 2 mm (that is, about 1 mm in radius). Therefore,
Tip 204B of Cage 20B and Tip 2 of Cage 20C
With the lens in contact with 04C, a gap of about 1 mm is formed between the inner wall 105 and the outer periphery of the lens (FIG. 4). On the other hand, the flat surface 104A has a thickness Ta that is approximately 1 mm thinner than the thicknesses Tb and Tc of the flat surfaces 104B and 104C. Therefore, the base 202A of the retainer 20A is flattened. In a state where the retainer is in contact with the inner wall 104A, the tip 204A of the retainer 20A is
Projection of about 2 mm from the surface of 05 (FIG. 1). As a result, a gap of about 1 mm occurs between the flat surface 104A and the lower surface of the base 202A of the holder 20A when the holder 20A holds the lens. This allows a margin for adjusting the positioning of the lens in the radial direction by the holder 20A.

Next, a method for manufacturing the optical element assembly 1 will be described with reference to FIGS. First, the retainers 20B and 20C are attached to predetermined positions of the cylindrical body 10 with bolts 201B and 201C, respectively. in this case,
The holders 20B and 20C are attached such that the tips 202B and 202C of the holders project about 1 mm from the inner wall 105 of the cylindrical body (FIG. 1). Next, as shown in FIG. 3, a spacer ring 30 for insulation and positioning in the height direction is attached to the cylindrical body 1.
The first lens 31 is inserted after the insertion into the bottom surface inside the 0.
The outer diameter of this lens 31 is the tip 202 of each cage.
A, 202B, and 202C are machined to have the same diameter as the circle formed by the three points, but the hole at the center has not been machined yet. The lens 31 is moved to the holders 20B and 2
The holder 20A is attached to a predetermined position of the cylindrical body 10 in a state where the lens 31 is brought into contact with the respective front ends 202B and 202C of 0C, and the lens 31 is fixed at three points by pushing the holder 20A with bolts 201A. Thereby, the lens 31 is positioned. In the same manner, the spacer ring 32, the lens 33, the spacer ring 34, the lens 3
5 and the spacer ring 36 are sequentially positioned in the cylindrical body 10. In such a process, each lens 31, 33,
35, the inner surface 105 of the cylindrical body 10, and the spacer 3
When the optical element assembly 1 is disassembled, cleaned, and then reassembled, it is desirable that the same phase of each lens as before disassembly can be reproduced by attaching a matching mark to 0, 32, and 34.

Next, the cover 37 is attached to the cylindrical body 10 by a known method such as a screw to securely fix the lens (FIG. 3). Thereafter, the lower flange 102 is fixed to a processing machine with a chuck, and drilling is performed in order from the lens 35 side to the bottom surface of the cylindrical body 10. In this case, a hole having an accuracy of 1 micron or less in coaxiality with the outer peripheral circle of the lower flange can be simultaneously formed in each lens and the bottom surface of the cylindrical body. As a result, the optical element assembly 1 having high positioning accuracy in which the cylindrical body 10, the holders 20A, 20B, and 20C and the lenses 31, 33, and 35 are integrated into a unit to produce a unit is manufactured (FIG. 4). The upper flange 101 is fixed to the processing machine with a chuck, and the lens
Drilling may be performed in this order. After drilling, the optical element assembly is removed from the processing machine and disassembled. At this time, the lid 37 and the retainer 20
Remove only A, take out each lens and spacer ring while keeping the retainers 20B and 20C attached to the cylinder 10. The same applies to the case where it is decomposed during washing.

When assembling the optical element assembly again, while alternately sandwiching each spacer ring and the lens, using the matching marks provided on the inner surface of each lens and the cylindrical body as a guide,
Each lens is arranged in the same procedure as above, and the lid 37 is attached. Since the retainers 20B and 20C are not detached from the cylindrical body 10, the state at the time of the first assembly is maintained, so that the positioning accuracy of the lens in the radial direction can be reproduced. Direction positioning accuracy can be reproduced. Therefore, the coaxiality of the holes of each lens can reproduce the accuracy before disassembly. In the above description, the embodiment in which only a plurality of lenses are assembled in the cylinder has been described, but the present invention is not limited to this, and an aperture member or a deflector is assembled instead of a lens, or It will be apparent to those skilled in the art that the present invention can be applied to a case where.

Next, an embodiment of an electron beam apparatus to which the optical element assembly 1 according to the present invention is attached will be described with reference to FIG. FIG. 5 schematically shows the electron beam device 6 of the present embodiment. The electron beam device 6 includes a primary optical system 6
0, a secondary optical system 70, and a detection device 80. The primary optical system 60 is an optical system that irradiates the surface of the sample S with an electron beam, and includes an electron gun 61 that emits an electron beam, an electrostatic deflector 62 that deflects the electron beam emitted from the electron gun,
A condenser lens 64 for focusing an electron beam, an aperture member 65 for determining an aperture angle, electrostatic deflectors 66 and 67 for scanning an electron beam on a sample, an E × B separator 68, and an objective lens 69. These are arranged in order along the optical axis M of the primary optical system 60 with the electron gun 61 at the top as shown in FIG. Deflector 62, condenser lens 64, aperture member 65, and electrostatic deflector 66
Is unitized as an optical element assembly 1 by a cylindrical body 10 and holders 20A, 20B, and 20C, and is integrally assembled to a lens barrel (not shown). The secondary optical system 70 includes an optical axis N that is inclined with respect to the optical axis M of the primary optical system near the E × B separator 68 of the primary optical system 60.
Are arranged along. The detection device 80 includes a detector 81.

In the above-mentioned electron beam apparatus, the electron beam emitted from the electron gun 61 is deflected by the electrostatic deflector 62 and focused by the condenser lens 64 to form a crossover on the electron gun side of the objective lens 69. Then, the objective lens 69 focuses on the sample S. In this case, the electron beam is deflected by the electrostatic deflector 66 and the electrostatic deflector 67 of the E × B separator 68, and scans and irradiates the sample S. Secondary electrons emitted from the sample S by the irradiation with the electron beam are accelerated and focused by an acceleration electric field applied between the objective lens 69 and the sample S, and pass through the objective lens 69. The secondary electrons that have passed through the objective lens are deflected by the E × B separator 68 in a direction along the optical axis N of the secondary optical system 70, and
Is detected by the detector 81, and the sample S is evaluated.

Next, a method of manufacturing a semiconductor device using an electron beam apparatus incorporating the optical element assembly according to the present invention will be described with reference to FIGS. FIG. 6 is a flowchart showing one embodiment of a method for manufacturing a semiconductor device according to the present invention. The steps of this embodiment include the following main steps. (1) Wafer manufacturing process for manufacturing a wafer (or wafer preparing process for preparing a wafer) (2) Mask manufacturing process for manufacturing a mask for manufacturing a mask used for exposure (or mask preparing process for preparing a mask) (3) ) Wafer processing step of performing necessary processing on the wafer (4) Chip assembling step of cutting out chips formed on the wafer one by one and making them operable (5) Chip inspection step of inspecting the completed chips Each of the main steps further comprises several sub-steps.

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 to form a large number of chips that operate as memories and MPUs. This wafer processing step includes the following steps. (1) A thin film forming step (CVD) for forming a dielectric thin film or wiring portion serving as an insulating layer, or a metal thin film forming an electrode portion.
(2) Oxidation step of oxidizing this thin film layer or wafer substrate (3) Lithography step of forming a resist pattern using a mask (reticle) to selectively process the thin film layer or wafer substrate (4) An etching step of processing a thin film layer or a substrate according to a resist pattern (for example, using a dry etching technique) (5) An ion / impurity implantation diffusion step (6) A resist peeling step (7) A step of inspecting a processed wafer The wafer processing step is repeated for the required number of layers to manufacture a semiconductor device that operates as designed.

FIG. 7 is a flowchart showing a lithography step which is the core of the wafer processing step shown in FIG. The lithography step includes the following steps. (1) A resist coating step of coating a resist on a wafer on which a circuit pattern has been formed in the previous step (2) A step of exposing the resist (3) A developing step of developing the exposed resist to obtain a resist pattern ( 4) Annealing Step for Stabilizing Developed Resist Pattern The above-described semiconductor device manufacturing step, wafer processing step, and lithography step are well known and need not be further described. The above (7)
When the defect inspection method and the defect inspection apparatus according to the present invention are used in the inspection process, even a semiconductor device having a fine pattern can be inspected with high throughput, so that 100% inspection can be performed, thereby improving the product yield and shipping defective products. Prevention becomes possible.

[0018]

According to the present invention, the following effects can be obtained. (1) An optical element assembly that combines a plurality of optical elements, such as lenses, with a cylinder and a holder, forms a unit, and simultaneously drills holes, thereby achieving high positioning accuracy among the plurality of optical elements with a simple configuration. Can be provided,
Further, an electron beam device provided with such an optical element assembly can be provided. (2) Even if the optical element assembly is reassembled after the optical element assembly is disassembled and cleaned by attaching a matching mark to the inner surface of the cylindrical body and each optical element housed in the cylindrical body during the production of the optical element assembly. In addition, high positioning accuracy before disassembly can be easily reproduced.

[Brief description of the drawings]

FIG. 1 is a plan view partially showing a cylinder and a holder in an optical element assembly according to the present invention.

FIG. 2 is an enlarged sectional view showing an attached state of a retainer.

FIG. 3 is a cross-sectional view of the optical element assembly taken along line GG of FIG. 1 showing a state before drilling, in which a plurality of optical elements such as lenses are assembled in a cylindrical body.

FIG. 4 is a cross-sectional view similar to FIG. 2, showing a state after drilling in the state of FIG. 2;

FIG. 5 is a diagram schematically showing an optical system of an electron beam apparatus incorporating the optical element assembly according to the present invention.

FIG. 6 is a flowchart illustrating a device manufacturing process.

FIG. 7 is a flowchart showing a lithography process.

[Explanation of symbols]

1: Optical element assembly 10: Cylindrical body 20A, 20B, 20C: Holder 31, 33, 35: Lens 101: Upper flange 102: Lower flange 103: Body portion 104A, 104B, 104C: Flat surface 105: Inner wall 201 , 201, 20
1: bolt

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 9/14 H01J 37/04 B 37/04 Z 37/12 37/12 G01R 31/28 L (72) Inventor Tsutomu Karima 11-1 Haneda-Asamachi, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 2G011 AA01 AE03 2G132 AA00 AD15 AF13 AL35 2H044 AA16 AA17 AA20 AC01 5C030 AA06 AA09 BB06 BB12 5C033 BB01 CC01

Claims (5)

[Claims] 1. An optical element assembly capable of setting an optical element to an electron beam device with high positioning accuracy, comprising: a cylindrical body capable of accommodating the plurality of optical elements therein; and a central axis of the cylindrical body at one end. A cylindrical body having a flange portion having an outer peripheral edge on the same circumference with the center as a center, and being detachably attached to a predetermined position in the electron beam device, housed in the cylindrical body A plurality of optical elements; and a plurality of sets of retainers attached to the cylinder at equal intervals in a circumferential direction, the tips having a tip that can protrude radially inward from an inner peripheral surface of the cylinder. And a plurality of sets of holders for holding the optical element at the tip so that the optical element can be adjusted in position, for an electron beam apparatus that is capable of processing the optical element while holding the optical element in the cylindrical body. Optical element assembly. 2. The optical element assembly according to claim 1, wherein the cylindrical body and the optical elements are the same as each other when the optical element assembly is disassembled and then reassembled. An optical element assembly having a matching mark for reproducing a phase. 3. A method for processing an optical element assembly for an electron beam device, comprising: (1) preparing a cylinder accommodating a plurality of the optical elements and attaching a plurality of retainers to the cylinder; (2) inserting a spacer and an unprocessed optical element into the cylindrical body, and holding the optical element by the plurality of sets of holders; and (3) holding the plurality of optical elements. (C) setting the cylindrical body on a processing machine and processing the cylindrical body and the plurality of optical elements in order; (4) removing the cylindrical body from the processing machine after the processing is completed; and (5) performing post-processing. Removing the optical element from the cylinder removed from the processing machine and performing post-processing on the cylinder and the optical element; and (6) holding the optical element after post-processing in the cylinder after post-processing. Positioning and fixing with a vessel . 4. The method according to claim 3, wherein the step of inserting the optical element into the cylinder and holding the optical element by a holder includes the step of attaching a matching mark to the cylinder and the optical element. A method characterized by the following. 5. A device manufacturing method, comprising: evaluating an in-process wafer using an electron beam apparatus provided with the optical element assembly according to claim 1 or 2.