JP2002208371A - Electron beam device and manufacturing method of such device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam device equipped with a mobile stage device which can continuously move at high speed with movement accuracy secured. SOLUTION: With the electron beam device 100, a main stage 3 is supported on a stage counter 2 through a non-contact bearing, and a sub-stage 5 moves in conjunction with the main stage 3 toward a given direction, the main stage 3 and the sub-stage 5 coupled with a stage-combining part 9 in free relative movement, and further, a wiring and piping part 8 is provided with a mobile stage device coupled with the sub-stage 5, at least one primary optical system irradiating a plurality of primary electron beams on a sample, and at least one secondary optical system leading the secondary electrons to at least one detector. The plurality of the primary electron beams are all irradiated on a place away from the distance limit of resolution of the second optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for evaluating a pattern of a wafer or a reticle at a high throughput using an electron beam, and more particularly to an improvement of a moving stage apparatus in such an electron beam apparatus.

[0002]

2. Description of the Related Art A moving stage device having an air bearing and driven by a linear motor is already known. Conventionally, the bearing rigidity of the bearing used in the moving stage is smaller than that of the mechanical type bearing, and if many power cables and piping are directly connected to the moving stage, the weight and rigidity of many power cables and piping will be reduced. However, there is a problem in that the force caused by such factors acts on the moving stage as a disturbance, which adversely affects the running accuracy. For this reason, it was necessary to minimize the wiring and piping in order to reduce disturbance. Further, in a conventional device for detecting secondary electrons generated when one electron beam is scanned, the S / N ratio cannot be made sufficiently large.

[0003]

One object to be solved by the present invention is to provide an electron beam apparatus having a moving stage device capable of continuously moving at a high speed while ensuring the moving accuracy. It is. Another object of the present invention is to obtain an electron beam capable of obtaining a signal having a necessary S / N ratio when the stage is moved at a high speed. Another problem to be solved by the present invention is to make the movement accuracy of the moving stage device extremely high. Still another problem to be solved by the present invention is to provide a method for manufacturing a device using such an electron beam apparatus.

[0004]

The above object is achieved by the following means. That is, one of the inventions of the present application is an electron beam apparatus that irradiates a sample with a primary electron beam and detects secondary electrons emitted from the sample, and includes a stage mount, a non-contact bearing on the stage mount. A main stage that moves the sample in a predetermined direction, a sub-stage that moves in the predetermined direction in conjunction with the main stage, a wiring pipe section connected to the sub-stage, the main stage and the sub-stage. A moving stage device having a linear motor that drives a stage in the predetermined direction and a connecting portion that connects the main stage and the sub-stage so as to be relatively movable;
At least one or more primary optical systems that irradiate the sample with a plurality of primary electron beams, and at least one or more secondary optical systems that guide the secondary electrons to at least one or more detectors, The primary electron beams are applied to positions separated from each other by a distance resolution of the secondary optical system. In this way, the main stage and the sub-stage of the moving stage device can be relatively moved, and by connecting the wiring pipe to the sub-stage, even if the weight and rigidity of the wiring pipe part is large, the movement accuracy of the main stage is thereby improved. The influence of the adverse effects is reduced, and high movement accuracy of the main stage can be secured. Therefore, piping and wiring can be directly connected from the electron beam device main body to the moving stage device.

In another aspect of the invention of the electron beam apparatus, the non-contact bearing is constituted by an air bearing. Thereby, the movement accuracy can be extremely increased.

Another aspect of the present invention provides a method of manufacturing a device using the above-described electron beam apparatus. This makes it possible to reduce the cost of the device manufacturing method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a view showing an embodiment of a moving stage device 1 provided in an electron beam device according to the present invention. A precision air guide 4 for the main stage 3, a mechanical guide 6 for the sub-stage 5, and a linear motor 7 for driving the main and sub-stages extend on the stage base 2.

On the lower surface of the main stage 3, an air bearing constituted by a block and an air pad is provided. The carriage of the linear motor 7 is fixed to the main stage 3, and the main stage 3 is moved by the air guide 4 in the X-axis direction according to the control current. Since the air guide 4 is used, the movement accuracy is very high, but the air guide 4 is not as rigid as the mechanical guide 6. On a top surface of a sample stage (not shown) provided on the main stage 3, a printed board or the like (not shown) is mounted.

The sub-stage 5 is guided by a mechanical guide 6 and is movable in the X-axis direction independently of the main stage 3.

The wires and pipes for transmitting electric power, compressed air, etc., are heavy and have high rigidity. Therefore, if they are pulled out from the electron beam apparatus main body (not shown) and directly connected to the main stage 3, X and X , Y and Z-axis directions and moments around each axis act, and the running accuracy of the main stage 3 deteriorates. Therefore, in the present embodiment, the wiring pipe 8 that causes disturbance is connected to the sub-stage 5 that has high rigidity but may have poor running accuracy.

In this embodiment, the thrust of the linear motor 7 is increased so that disturbance in only the X-axis direction can be handled. The stage connecting portion 9 is installed on the drive shaft of the main stage, that is, on the thrust axis of the linear motor 7, and transmits the thrust of the linear motor 7 not only to the main stage 3 but also to the sub-stage 5, The sub stage 5 can be driven without providing a dedicated driving source. In addition, the stage connecting portion 9 prevents the main stage 3 from receiving a force only in the X-axis direction on the thrust axis and not receiving a force in the Y and Z-axis directions and a rotational moment around the X, Y and Z axes. The running accuracy of the main stage 3 can be improved.

FIG. 2 shows an example of the configuration of the stage connecting section 9 of FIG. 2 that can rotate around X, Y and Z axes
The two ball bearings 91 and 92 face each other,
A ball bearing 91 is fixed to the main stage 3 and a ball bearing 92
Are fixed to one end of the support member 93. Support member 93
Is fixed to the main stage. The arm 50 of the sub-stage 5 is inserted between the opposing ball bearings 91 and 92. In order to apply an appropriate preload to the ball bearings 91 and 92 and the arm 50, a screw portion 94S and a nut 94
A preload adjusting section 94 constituted by N is provided.

By configuring the stage connecting portion 9 in this manner, the main stage 3 and the sub-stage 5 are mechanically coupled only to the force Fx in the X-axis direction, and to the force Fy in the Y- and Z-axis directions.
And Fz and the rotational moments Mx, My and Mz are:
It does not work by mechanical coupling. Therefore, even if the running accuracy of the sub-stage 5 deteriorates due to the running error of the mechanical guide 6 or the disturbance of the wiring pipe 8, the thrust of the linear motor 7 is applied to the sub-stage 5 without adversely affecting the main stage 3. Can be transmitted.

FIG. 3 shows another example of the configuration of the stage connecting portion of FIG. This stage connecting portion 9 'is a ball bearing unit 91' in which ball bearings 91'A and 91'B rotatable around the X, Y and Z axes are assembled so as to face each other.
Are fixed to the tip of the sub stage 5 ', and the ball bearing unit 91' is sandwiched between the main stage 3 and the support member 93 '. The preload adjustment is performed by adjusting the distance between the main stage 3 and the support member 93 'by the fixing screws 95 and 96. With the stage connecting portion 9 'having such a configuration, the same advantage as that of the stage connecting portion 9 in FIG. 2 can be obtained.

In the embodiment shown in FIG. 1, transmission of electricity, pneumatic pressure, and the like between the main stage 3 and the sub-stage 5 is as follows.
Since the distance between the two stages is small and hardly changes, it is sufficient to use a flexible cable, a bellows made of a cloth lined with an airtight resin, or the like.

FIG. 4 is a view showing one embodiment of an electron beam apparatus 100 provided with the above-mentioned moving stage apparatus.
In FIG. 1, an electron beam C emitted from an electron gun 101 is focused by an electrostatic lens 102 to form a crossover 104. Below the electrostatic lens 102, a first multi-aperture plate 103 having a plurality of openings (for example, 103a to 103i in the present invention) is arranged, thereby forming a plurality of primary electron beams. Each of the primary electron beams formed by the first multi-aperture plate 103 is reduced by the electrostatic reduction lens 105 and projected onto the position indicated by the point 106, focused at the point 106, and then focused on the electrostatic objective lens 107. Focuses on the sample S. The sample S is placed on the moving stage device G according to the present invention. A plurality of primary electron beams emitted from the first multi-aperture plate 103 are transferred to an electrostatic reduction lens 105 and an electrostatic objective lens 107.
The sample S is simultaneously deflected so as to scan the surface of the sample S by the electrostatic deflector 108 disposed therebetween. In order to eliminate the effect of the field curvature aberration of the electrostatic reduction lens 105 and the electrostatic objective lens 107, as shown in FIG. The projections in the directions have a structure with equal intervals. A plurality of points of the sample S are irradiated by the plurality of focused primary electron beams, and the secondary electrons emitted from the plurality of irradiated points are attracted to the electric field of the electrostatic objective lens 107 to be finely focused. Then, the light is deflected by the E × B separator 109 and input to the secondary optical system. The secondary electron image is formed at a point 110 closer to the electrostatic objective lens 107 than at the point 106. This is because each primary electron beam has energy of 500 eV on the sample surface, while secondary electrons have energy of only several eV. The secondary optical system is an electrostatic magnifying lens 11
1, 112, and these electrostatic magnifying lenses 11
The secondary electrons that have passed through the first multi-aperture plate 1
An image is formed at the positions of the thirteen openings (113a to 113i shown by broken lines in FIG. 5 exemplarily). This image is detected by the corresponding detector 114. As shown in FIG. 5, the plurality of openings formed in the second multi-aperture plate 113 disposed in front of the detector 114 and the plurality of openings formed in the first multi-aperture plate 103 are different from each other. , One for one. Each detector 114 converts the detected secondary electrons into an electric signal representing its intensity. The electric signals output from the respective detectors are respectively amplified by the amplifier 115, then received by the image processing unit 116, and converted into image data. Image processing unit 11
Since a scanning signal for deflecting the primary electron beam is further supplied to 6, the image processing unit 116 displays an image representing the surface of the sample S. By comparing this image with a standard pattern, a defect of the sample S can be detected. In addition, the sample S is moved near the optical axis A of the primary optical system by registration, and a line is scanned by line scanning. The line width of the pattern on the sample S can be measured by extracting the width evaluation signal and appropriately correcting the width evaluation signal. Here, when the primary electron beam that has passed through the opening of the first multi-aperture plate 103 is focused on the sample surface and the secondary electrons emitted from the sample S are detected by the detector 114, the primary optical system Special care must be taken to minimize the effects of three aberrations, i.e., distortion, field curvature and field astigmatism. Next, regarding the relationship between the intervals between the plurality of primary electron beams and the secondary optical system, crosstalk between the beams can be eliminated by separating the intervals between the beams by a distance larger than the resolution of the secondary optical system. be able to. Also, if the number of beams is n, to obtain a signal with the same S / N ratio, n
The sample stage can be moved continuously at twice the speed.

Next, a method of manufacturing a semiconductor device using the electron beam apparatus 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 such a semiconductor device. 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 a 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 (rectile) 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 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. The above (7)
When the defect inspection method and the defect inspection device according to the present invention are used in the inspection process, even a semiconductor device having a fine pattern can be inspected or exposed by a low-cost and highly reliable device, thereby improving the product yield, It is possible to prevent defective products from being shipped.

[0020]

According to the present invention, the following effects can be obtained. (1) According to the moving stage device of the present invention, the wiring and piping section is connected to the sub-stage, and the main stage and the sub-stage are connected so as to be relatively movable by the connecting section. Even if is large,
The main stage can be moved with high precision, and a series of operations can be completed quickly. (2) Since the non-contact bearing provided on the stage base is an air bearing, extremely high moving accuracy can be secured. (3) By incorporating the moving stage device of the present invention into an electron beam device, it is possible to evaluate a sample with high inspection accuracy and with high throughput in proportion to the number of beams. (4) By manufacturing a device using the electron beam apparatus according to the present invention, the cost of the device manufacturing process can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a moving stage device of the present invention.

FIG. 2 is an enlarged view showing a configuration example of a stage connecting portion of the moving stage device of the present invention.

FIG. 3 is an enlarged view similar to FIG. 2, but showing another configuration example of a stage connecting portion of the moving stage device of the present invention.

FIG. 4 is a diagram showing an outline of an optical system of an electron beam apparatus having the moving stage device of the present invention.

FIG. 5 is a diagram showing an arrangement of respective openings in a first multi-aperture plate and a second multi-aperture plate of the electron beam apparatus of FIG. 4;

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

FIG. 7 is a flowchart showing a lithography process.

[Explanation of symbols]

1: Moving stage device 2: Stage base 3: Main stage 4: Precision air guide 5: Substage 6: Mechanical guide 7: Linear motor 8: Wiring piping 9, 9 ': Stage connecting portion 91, 92: Ball bearing 91' : Ball bearing unit 91'A, 9
1'B: Ball bearing 100: Electron beam device 101: Electron gun 102: Electrostatic lens 103: First
Multi-aperture plate 105: electrostatic reduction lens 107: electrostatic objective lens 108: electrostatic deflector 109: Ex
B separators 111 and 112: electrostatic magnifying lens 113: second
Multi-aperture plate 114: Detector 115: Amplifier 116: Image processing unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Mamoru Nakasuji, 11-1, Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Meister Co., Ltd. (72) Inventor: Shinji Noji 11-1, Asahi-cho, Haneda, Ota-ku, Tokyo Stock Company Ebara Corporation (72) Inventor Toru Satake 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 4M106 AA01 BA02 CA38 DB05 DB12 DB14 DJ04 DJ18 DJ19 5C001 AA01 AA04

Claims (3)

[Claims] 1. An electron beam apparatus for irradiating a sample with a primary electron beam and detecting secondary electrons emitted from the sample, comprising: a stage mount; and a non-contact bearing provided on the stage mount. A main stage that moves the sample in a predetermined direction, a sub-stage that moves in the predetermined direction in conjunction with the main stage, a wiring and piping section connected to the sub-stage, and the main stage and the sub-stage A moving stage device having a linear motor driven in the direction of and a connecting portion for connecting the main stage and the sub-stage relatively movably, and at least one or more primary optics for irradiating the sample with a plurality of primary electron beams System, and at least one or more secondary optical systems for guiding the secondary electrons to at least one or more detectors, wherein the plurality of primary electron beams are Electron beam apparatus which is characterized in that intended to be illuminated at a position away from the axial resolution of the secondary optical system. 2. The electron beam apparatus according to claim 1, wherein:
The electron beam device, wherein the non-contact bearing is an air bearing. 3. A device manufacturing method for performing a defect inspection of a device using the electron beam apparatus according to claim 1.