JP2002150985A - Electron beam apparatus and manufacturing method of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for irradiating primary electrons on substrate surface and generating the secondary electrons and to test for any fault in the substrate surface, based on this. SOLUTION: In an electron beam apparatus for detecting secondary electron beam generated from the substrate surface, according to irradiation, by irradiating the primary electron beam on the surface of the substrate 17 by means of an electron gun 1, the electron beam apparatus has a discharge means for discharging electric charges generated on the surface of the substrate, by contacting a dicing line 19 on the surface of the substrate, to partition the substrate into plural dies is provided. For this apparatus, the surface of the substrate can be tested by comparing an image image formed by the secondary electron beam with the picture image stored beforehand, or by testing the pattern line width of the patterns on the surface of the substrate, based on the secondary electron beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a minimum line width of 0.1 μm.
Apparatus suitable for performing high-throughput and high-reliability pattern inspection such as a defect inspection of a substrate on which the following pattern is formed, or a line width measurement, and a substrate inspection during a manufacturing process using the same apparatus. The present invention relates to a method for manufacturing a device or the like.

[0002]

2. Description of the Related Art A surface of a semiconductor substrate placed on a support is irradiated with a primary electron beam, a surface image is formed based on the secondary electron beam from the surface, and the image is compared with a previously stored image. Thus, an electron beam apparatus that determines the presence or absence of a defect on the surface of a semiconductor substrate, or measures the pattern line width of a pattern formed on a semiconductor substrate based on a secondary electron beam, and inspects for the presence or absence of a defect on the same pattern line, Are known.

[0003]

In such an electron beam apparatus, when the irradiation amount of primary electrons is increased, the surface of the substrate is charged, and the image formed based on the secondary electrons is distorted, There is a possibility that correct defect inspection cannot be performed due to a change in brightness.

Accordingly, the present invention provides an electron beam apparatus capable of minimizing the influence of such charging as much as possible and capable of properly inspecting a defect of a substrate such as a substrate. With the goal. Further, the present invention provides a method of manufacturing a device using a substrate such as a semiconductor substrate while efficiently inspecting a substrate in the middle of a manufacturing process using the same electron beam apparatus. Aim.

[0005]

That is, the present invention provides an electron beam for irradiating a primary electron beam to a substrate surface with an electron gun and detecting a secondary electron beam generated from the substrate surface in response to the irradiation. An electron beam apparatus, comprising: a discharge unit configured to contact a dicing line on a surface of a substrate for dividing the substrate into a plurality of dies to discharge electric charges generated on the surface of the substrate. I do. In this apparatus, the above-described problem of the conventional electron beam apparatus can be solved by the discharging means having the above-described configuration.

More specifically, at least one or more primary electron optical systems for irradiating the substrate surface with a plurality of primary electron beams, and at least one or more secondary electron beams for guiding the secondary electron beams to at least one or more detectors. And a secondary electron optical system, wherein the plurality of primary electron beams are applied to positions separated from each other by a distance resolution of the secondary electron optical system.

In another example, based on a secondary electron beam,
It is also possible to measure the pattern line width of the pattern formed on the substrate surface and inspect the presence or absence of the defect.

The present invention provides a device characterized by having a plurality of such electron beam devices arranged side by side. By providing a plurality of electron beam devices, inspection of the substrate surface can be performed in parallel, and inspection can be performed efficiently.

Further, the present invention provides a method for manufacturing a device using a substrate, wherein the device surface is inspected during the manufacturing process using the apparatus as described above. I do. Even a semiconductor device having a fine pattern can be inspected efficiently, so that 100% inspection can be performed, thereby improving the product yield and preventing shipment of defective products.

[0010]

FIG. 1 is a view for explaining an embodiment of a defect inspection apparatus using an electron beam according to the present invention. In this device, the primary electron beam 2 emitted from the electron gun 21 is
The surface of the substrate, that is, the substrate 17 is irradiated through an electron beam irradiation system composed of lenses 3 and 4, and secondary electron beams emitted from the surface are irradiated through image projection systems 9, 8, 5, 12, and 13. Then, the detected signal is temporarily stored in the image storage means 15, and is compared with an image stored in advance by the means 16 to determine the presence or absence of a defect on the substrate surface. ing. Here, reference numeral 5 is an ExB separator composed of an electrode 6 and an electrode 7,
8 and 9 are objective lenses, and 12 and 13 are magnifying lenses.

As described above, when the amount of primary electrons to be irradiated increases, the surface of the substrate 17 is charged, and a correct image on the surface may not be obtained. For this reason, in this apparatus according to the present invention, a plurality of needle-shaped conductors 18 are brought into contact with the central portion of the dicing line 19 between the dies formed on the substrate, and the charged electric charge on the substrate surface is released through the conductors. Like that. The conductor is usually brought to the same potential as the substrate. The material of the conductor is preferably a high melting point metal such as tungsten or tantalum.

In the illustrated apparatus, two units each consisting of elements 1 to 16 from the electron gun to the means for judging the presence or absence of a defect are provided corresponding to two dies each having one die. It is also possible to install three or more units with a pitch that is an integral multiple of the die size. In such an apparatus, the throughput can be increased by performing the defect inspection as described above in parallel. .

Further, as described above, instead of performing an inspection of the surface by comparing an image of the substrate surface formed from the secondary electron signals with an image stored in advance, a secondary electron beam is formed. Based on this, it is also possible to measure the line width of the pattern and inspect the presence or absence of the defect.

In the apparatus according to the present invention, since the charge on the surface of the substrate 17 can be rapidly reduced as described above, the primary electron dose does not affect the image formed by the secondary electron beam. And can increase.
In one embodiment, the primary electron dose could be increased to about three times that of the related art without substantially affecting the charging. On the dicing line, even if a discharge occurred between the charged electric charge and the conductor and the substrate surface was roughened, no particular problem occurred.

FIG. 2 schematically shows another embodiment of the electron beam apparatus according to the present invention. In this device,
As in FIG. 1, a conductor is provided to contact the dicing line of the substrate to discharge the surface of the substrate, but a plurality of electron beams are emitted from an electron beam emitted from one electron gun 21. It is formed so that the surface of the substrate can be inspected by each electron beam.

That is, in this device, the primary electron beam emitted from the electron gun 21 is
To form a crossover at point 24.

At a position below the condenser lens 22,
A first multi-aperture plate 23 having a plurality of openings is disposed so as to be orthogonal to the optical axis, and a primary electron beam from an electron gun is passed through the openings to be converted into a plurality of electron beams. Each of the plurality of primary electron beams divided by the first multi-aperture plate 23 is reduced by the reduction lens 25 and focused and projected on 35. After focusing at the point 35, the objective lens 27 focuses on the substrate 28. The plurality of primary electron beams emitted from the first multi-aperture plate 23 are transmitted to the reduction lens 25 and the objective lens 2.
7 is deflected so as to scan the surface of the substrate 28 at the same time.

In order to eliminate the influence of the field curvature aberration of the reducing lens 25 and the objective lens 27, as shown in FIG.
The intervals between the lines projected on the line extending in the direction (horizontal direction in the figure) are set to be equal. Note that a circle shown by a dotted line indicates an opening formed in a second multi-aperture plate 23 described later.

A plurality of focused primary electron beams irradiate a plurality of points on the substrate 28, and the secondary electron beams emitted from the plurality of irradiated points are attracted to the electric field of the objective lens 27. Then, the light is focused finely, deflected by the E × B separator 26, and input to the secondary optical system. The secondary electron image focuses on point 36 closer to objective lens 27 than point 35. This is because each primary electron beam has energy of 500 eV on the substrate surface, whereas the secondary electron beam has energy of only several eV.

The secondary optical system has magnifying lenses 29 and 30, and the secondary electron beam passing through these lenses 29 and 30 passes through a plurality of openings of the second multi-aperture plate 31 and a plurality of detectors. An image is formed at 32. Note that the plurality of openings formed in the second multi-aperture plate 31 disposed in front of the detector 32 and the plurality of openings formed in the first multi-aperture plate 23 correspond one-to-one. .

Each detector 32 converts the detected secondary electron beam into an electric signal representing its intensity. The electric signals output from the respective detectors are respectively amplified by the amplifier 33, and then received by the image processing unit 34, where they are converted into image data. The image processing unit 34 includes
Since a scanning signal for deflecting the next electron beam is further supplied, the image processing unit 34 displays an image representing the surface of the substrate 28. By comparing this image with the standard pattern,
A defect of the substrate 28 can be detected, and the substrate 28 is moved close to the optical axis of the primary optical system by registration, and a line width evaluation signal is taken out by line scanning, and this is appropriately calibrated. Thereby, the line width of the pattern on the substrate 28 can be measured.

Here, the primary electron beam passing through the opening of the first multi-aperture plate 23 is focused on the surface of the substrate 28, and the secondary electron beam emitted from the substrate 28 is imaged on the detector 32. At this time, it is better to take care to minimize the effects of the three aberrations of the primary optical system and the secondary optical system, such as distortion, field curvature, and field astigmatism. An interval between a plurality of primary electron beams;
Regarding the relationship with the secondary optical system, the interval between the primary electron beams,
If the distance is larger than the aberration of the secondary optical system, crosstalk between a plurality of beams can be eliminated.

Next, with reference to FIGS. 4 and 5, a method for manufacturing a semiconductor device using the above-described apparatus according to the present invention will be described. FIG. 4 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) Substrate manufacturing process for manufacturing a substrate (semiconductor wafer) (or substrate preparing process for preparing a substrate) (2) Mask manufacturing process for manufacturing a mask for manufacturing a mask used for exposure (or mask preparation for preparing a mask) Step) (3) Substrate processing step of performing necessary processing on the substrate (4) Cutting out chips formed on the substrate one by one,
Chip assembling step to make it operable (5) Chip inspecting step to inspect the completed chip Each of the above main steps further includes several sub-steps.

Among these main steps, the substrate processing step (3) has a decisive effect on the performance of the semiconductor device. In this step, designed circuit patterns are sequentially laminated on a substrate to form a large number of chips that operate as memories and MPUs. This substrate 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, etc.
(B) Oxidation step of oxidizing this thin film layer and substrate substrate (c) Lithography step of forming a resist pattern using a mask (rectile) to selectively process the thin film layer and substrate substrate (D) An etching process for processing a thin film layer or substrate according to a resist pattern (for example, using a dry etching technology) (e) An ion / impurity implantation / diffusion process (f) A resist stripping process (g) A process for inspecting the processed substrate The substrate processing step is repeated as many times as necessary to produce a semiconductor device that operates as designed.

FIG. 5 is a flowchart showing a lithography step which is the core of the substrate processing step of FIG. The lithography step includes the following steps. 1) a resist coating step of coating a resist on a substrate 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) developing Annealing process for stabilizing the resist pattern formed The semiconductor device manufacturing process, the substrate processing process, and the lithography process are well known and need no further explanation.

[0026]

According to the present invention, the charge on the surface of the substrate 17 can be rapidly reduced as described above.
The primary electron dose can be increased without affecting the image formed by the secondary electron beam, and the inspection can be performed more appropriately than the conventional one. Further, with the use of the electron beam apparatus according to the present invention, even a semiconductor device having a fine pattern can be inspected with a high throughput, so that 100% inspection can be performed, and the product yield can be improved.
It is possible to prevent defective products from being shipped.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an apparatus provided with two electron beam apparatuses for inspecting a defect on a substrate surface according to the present invention.

FIG. 2 is a schematic explanatory view of an electron beam device according to another embodiment of the present invention.

FIG. 3 is a plan view of a multi-aperture plate in the electron beam apparatus of FIG.

FIG. 4 is a view schematically showing a process for manufacturing a semiconductor device using a semiconductor substrate.

FIG. 5 is a flowchart showing a lithography step which is a core of the substrate processing step of FIG. 4; DESCRIPTION OF SYMBOLS 1 Electron gun 3, 4 Lens system 17 Substrate 9, 8, 5, 12, 13 Mapping projection system 14 Detector 15 Image storage means 15 16 Comparison means 17 Substrate 18 Conductor 19 Dicing line 21 Electron gun

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G21K 5/04 H01J 37/28 B 5C001 H01J 37/28 H01L 21/66 J 5C033 H01L 21/027 G01R 31 / 28L 21/66 H01L 21/30 502V (72) Inventor Takeshi Murakami 11-1 Haneda Asahicho, Ota-ku, Tokyo Inside Ebara Corporation (72) Inventor Shinji Noji 11-1, Haneda Asahi-cho, Ota-ku, Tokyo No. within Ebara Corporation (72) Inventor Toru Satake 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation (72) Inventor Kenji Watanabe 11-1 Asahi-cho, Haneda, Ota-ku, Tokyo Ebara Corporation F term (reference) 2F067 AA26 BB04 CC17 HH06 HH13 JJ05 KK04 LL16 RR30 SS13 2G001 AA03 AA10 BA07 CA03 DA01 DA02 DA06 EA04 FA01 FA06 GA05 GA0 7 KA03 KA20 LA11 MA05 SA10 2G011 AA01 AC33 AD02 AE01 2G032 AD08 AF07 4M106 AA01 BA02 CA38 DB02 DB04 DB05 DB12 DB30 DE21 DJ18 DJ21 5C001 BB07 CC04 5C033 UU03 UU10

Claims (5)

[Claims] 1. An electron beam apparatus which irradiates a primary electron beam onto a substrate surface with an electron gun and detects a secondary electron beam generated from the substrate surface in response to the irradiation, partitions the substrate into a plurality of dies. In contact with the dicing line on the substrate surface,
An electron beam apparatus comprising: discharge means for discharging electric charges generated on a surface of the substrate. 2. The electron beam apparatus according to claim 1, wherein
At least one or more primary electron optical systems for irradiating the substrate surface with a plurality of primary electron beams;
At least one or more secondary electron optical systems for leading to the above-mentioned detector, wherein the plurality of primary electron beams are applied to positions separated from each other by a distance resolution of the secondary electron optical system. Electron beam device. 3. The electron beam apparatus according to claim 1, wherein
An electron beam apparatus, wherein a predetermined pattern is formed on the surface of the substrate, and based on the secondary electron beam, a pattern line width of the pattern is measured to check for a defect. . 4. An apparatus comprising a plurality of electron beam devices according to claim 1 arranged side by side. 5. A method of manufacturing a device using a substrate, wherein the device according to claim 1 is used to inspect a surface of the substrate during a manufacturing process. Method.