KR100995004B1 - Wafer transfer of wafer inspection system for scanning electron microscope - Google Patents

Abstract

PURPOSE: A wafer transfer of wafer inspection system for scanning electron microscope is provided to prevent a wafer from floating and being separated from a wafer holder by a shutter plate on the wafer holder. CONSTITUTION: A wafer is provided at a station holder(10). A wafer holder(20) receives a wafer and guides it to main inspection chamber. A shutter plate unit is arranged on the wafer holder, and includes a shutter plate(31). A wafer transfer arm(40) transfers the wafer to the station holder and the both sides of the wafer holder.

Description

Wafer Transfer System for Wafer Inspection System using Electron Microscopy {Wafer Transfer of Wafer Inspection system for Scanning Electron Microscope}

The present invention relates to a wafer transfer apparatus of a wafer inspection system using an electron microscope, and more particularly, to wafer inspection of a wafer inspection system using an electron microscope that can accurately inspect non-conductive wafers and transfer wafers stably. Relates to a device.

Integrated circuits such as semiconductors and LEDs have been highly integrated due to continuous technological developments, and the minimum line width of the integrated circuits required for this has also been miniaturized by several micrometers.

In addition, equipment for measuring and inspecting the line width of a high integrated circuit is also being moved from a high magnification optical microscope to a scanning electron microscope (SEM) that can observe higher magnification using a charged particle beam such as an electron beam. .

This electron microscope, as is generally known, is secondary to the electron beam that collides with the wafer when the electron beam generated by the electron gun is scanned onto the wafer (integrated circuit) formed on the inspection table via the focusing module, the scanning coil and the object module. The electrons are generated, and the secondary electrons are converted into video signals and displayed on the display device as an image, thereby measuring and inspecting the high integrated circuit line width of the wafer.

A wafer inspection system 101 using such an electron microscope is shown briefly in FIG. As shown in this figure, the wafer inspection system 101 using the electron microscope includes a main inspection chamber 120 in which the electron microscope 110 is installed, and a cassette table on which an inspection waiting and inspection-completed wafer A are loaded. The wafer A, which is provided between the 130 and the main inspection chamber 120 and the cassette table 130, is transferred from the cassette table 130 to the main inspection chamber 120 or the main inspection chamber 120. The wafer transfer chamber 150 is provided with a wafer transfer device 201 for transferring the inspected wafer A to the cassette table 130.

Among them, the conventional wafer transfer device 201 installed inside the wafer transfer chamber will be described in detail with reference to FIG. 2.

Conventional wafer transfer apparatus has a station holder 210 to wait before the wafer (A) is supplied from the cassette table 130 or discharged to the cassette table 130, and a wafer (A) waiting to be supplied to the station holder (210) It includes a wafer holder 220 for receiving the wafer holder 220 to enter and exit the main inspection chamber 120, and a wafer transfer arm 230 for transferring the wafer A to both sides of the station holder 210 and the wafer holder 220.

On the upper surfaces of the dual station holder 210 and the wafer holder 220, the wafer transfer arm 230 moves to the center region of each holder to seat the wafer A on the upper surface of each holder or the upper portion of each holder. The transfer arm air space 211 and the transfer arm flow space 221 are formed to lift the wafer A seated on the surface, respectively.

Therefore, the upper surface of the station holder 210 and the wafer holder 220 is not formed flat in general, and the upper surface of the wafer A is loaded, the transfer arm waiting space 211, and the transfer arm flow space 221 up and down heights. It is formed of non-flat surfaces with differences.

The wafer transfer process of the conventional wafer transfer device 201 will be briefly described. First, before the wafer A is supplied from the cassette table 130 to the station holder 210, the wafer transfer arm 230 is a station holder ( It is located in the transport arm waiting space 211 of 210.

In this state, when the wafer A supplied from the cassette table 130 is loaded on the upper surface of the station holder 210, the wafer transfer arm 230 is lifted from the transfer arm waiting space 211 of the station holder 210. While lifting the wafer A.

Thereafter, while the wafer transfer arm 230 moves to the upper region of the wafer holder 220, the wafer A is lowered to the transfer arm flow space 221 of the wafer holder 220 while the wafer A is moved to the wafer holder 220. Load on top

When the wafer A is loaded in the wafer holder 220, the wafer holder 220 is drawn from the wafer transfer chamber 150 into the main inspection chamber 120 by driving the wafer holder driver 240. The wafer transfer arm 230 is naturally located outside the wafer holder 220 through the transfer arm flow space 221 of the wafer holder 220.

Meanwhile, when the inspection of the wafer A is completed in the main inspection chamber 120, the wafer holder 220 is driven from the main inspection chamber 120 by the wafer holder driving unit 240. Is withdrawn. In this case, the wafer transfer arm 230 is naturally positioned under the wafer A loaded on the wafer holder 220 through the transfer arm flow space 221 of the wafer holder 220.

In this state, the wafer transfer arm 230 lifts the wafer A while rising from the transfer arm flow space 221 of the wafer holder 220. Then, while the transfer arm of the wafer A moves to the station holder 210, the wafer A is lowered into the transfer arm flow space 211 of the station holder 210 to move the wafer A to the upper surface of the station holder 210. Load it.

The wafer A loaded in the station holder 210 in the state of being inspected is discharged to the cassette table 130 by the wafer discharge means 160.

However, the wafer transfer apparatus 201 of the wafer inspection system using the conventional electron microscope has a transfer arm flow space formed in the wafer holder 220 in a state where the wafer A is loaded on the upper surface of the wafer holder 220. The non-contact area b, which is not in close contact between the wafer A and the wafer holder 220, is formed as large as 221.

As a result, in the case of the non-conductive wafer A such as the sapphire wafer or the gallium arsenide wafer, the contact between the wafer A and the upper surface of the wafer holder 220 during the inspection of the non-conductive wafer A by the electron microscope 110 is performed. Since the distribution of electrons is formed differently in the region a and the non-contact region b, a problem arises in that the inspection of the non-conductive wafer A cannot be performed accurately.

The problem will be described in more detail with reference to FIG. 3.

As shown in FIG. 3 and described above, the wafer transfer device 201 of the wafer inspection system using a conventional electron microscope is provided with the wafer A by the transfer arm flow space 221 formed in the wafer holder 220. The contact area a and the non-contact area b may be formed between the upper surfaces of the wafer holder 220.

On the other hand, a negative electric field is formed in the wafer holder 220 in the process of loading the non-conductive wafer into the wafer holder 220 and inspecting the non-conductive wafer A with the electron microscope 110 in the main inspection chamber 120. The electron beam scanned from the electron microscope 110 to the surface of the insulator wafer A is also composed of negative electrons.

At this time, the negative electrons of the electron beam scanned by the electron microscope 110 are stacked on the surface of the non-conductive wafer A without finding a passage through which electricity can flow. The negative electrons of the electron beam continuously scanned by the negative electrons of the stacked electron beams are not uniformly distributed on the surface of the nonconductive wafer A by the law of the electric field, and are pushed to the non-contact area of the wafer holder 220.

At this time, in the contact area of the wafer holder 220 in contact with the non-conductive wafer A, since the negative electric field applied to the wafer holder 220 extends to the surface of the non-conductive wafer A, electrons of the electron beam having the same polarity are pushed out. There are only a few electrons.

Accordingly, a phenomenon in which electrons are distributed in different amounts in the contact area between the non-conductive wafer A and the wafer holder 220 and the non-contact area corresponding to the transfer arm flow space 221 appears.

As a result, the partial contact area (a) having a small amount of electron distribution is less disturbed to the electron beam falling on the non-conductive wafer (A), which does not cause a problem in forming the secondary signal of the electron microscope (110). In the non-contact region corresponding to 221, the electron beam does not touch the surface of the non-conductive wafer A and thus cannot form a secondary signal, thereby failing to produce an image on the electron microscope 110.

As a result, a problem arises in that the inspection of the non-conductive wafer A cannot be made accurately.

On the other hand, in the wafer transfer apparatus 201 of the wafer inspection system using the conventional electron microscope, the wafer A is unstable on the upper surface of the wafer holder 220 by the transfer arm flow space 221 formed in the wafer holder 220. Since the wafer holder 220 moves closely between the main inspection chamber 120 and the wafer transfer chamber 150, there is a problem in that unstable transfer such as wafer A flow and departure occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wafer transfer apparatus of a wafer inspection system using an electron microscope that can accurately inspect non-conductive wafers and can stably transfer wafers.

According to the present invention, a wafer holder in which an electron microscope enters and exits an installation area and is formed with a transfer arm flow space stepped from an upper surface to a lower portion, and a wafer is transferred from the outside to the wafer holder by moving and lifting driving. A wafer transfer apparatus for a wafer inspection system using an electron microscope having a wafer transfer arm, the wafer transfer apparatus comprising: a metal plate having a larger area than the wafer and coupled to an upper surface of the wafer holder; A shutter plate having at least one pair of transfer arm lifting slits opened outwardly; The wafer transfer arm is achieved by a wafer transfer apparatus of a wafer inspection system using an electron microscope, characterized in that a wafer loading bar corresponding to the transfer arm lift-up slit is formed at a free end of the wafer transfer arm. do.

Here, the lower portion of the shutter plate is preferably provided with a metal shutter for opening and closing the transfer arm lifting slit.

In addition, the shutter plate and the shutter is effectively provided with a stainless plate.

In addition, it is more preferable that the shutter plate and the shutter have a thickness of 0.3 mm to 1 mm.

According to the present invention, there is provided a wafer transfer apparatus of a wafer inspection system using an electron microscope for accurately inspecting an insulator wafer and transferring the wafer stably.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the present invention.

At this time, the present invention is the same as the conventional structure of the wafer inspection system using the electron microscope except the wafer transfer apparatus. Accordingly, hereinafter, only the wafer transfer apparatus according to the present invention will be described, and the above-described conventional background art will be described with respect to the remaining components that are the same as before.

Figure 4 is a perspective view of the wafer transfer device installation area of the wafer inspection system using an electron microscope according to the present invention, Figure 5 is an exploded perspective view of the wafer holder and shutter plate unit of the wafer transfer device according to the present invention.

As shown in these figures, the wafer transfer apparatus 1 according to the present invention receives the station holder 10 waiting for the wafer A and the wafer A waiting to be supplied to the station holder 10. A wafer holder 20 for entering and exiting the inspection chamber 120, a shutter plate unit 30 provided on an upper surface of the wafer holder 20 to form a loading surface on which the wafer A is brought into full contact, and a wafer A ) And a wafer transfer arm 40 for transferring the station holder 10 and the wafer holder 20 to both sides.

The station holder 10 is the same as the station holder 210 of the conventional wafer transfer apparatus 201 described above, before the wafer A is supplied from the cassette table 130 or discharged to the cassette table 130 on the upper surface thereof. The standby wafer loading surface is formed. In addition, a transfer arm waiting space 11 is formed on the station holder 10 so that the wafer transfer arm 40 can stand by under the wafer loading surface and lift the wafer.

The wafer holder 20 is formed of a plate member having a predetermined thickness, and is installed to reciprocate the inside of the wafer transfer chamber 150 and the main inspection chamber 120 by the wafer holder driver 23. The wafer holder 20 has a transfer arm flow space 21 so that the wafer transfer arm 40 can be located at the lower portion of the wafer A loaded on the wafer holder 20 in the transfer arm toward the station holder side. ) Is formed stepped.

On the other hand, the shutter plate unit 30 is coupled to the upper surface of the wafer holder 20, the shutter plate 31 to form a loading surface of the wafer A, and the transfer arm lifting slit 33 of the shutter plate 31 to be described later ) And a shutter 35 for opening and closing the shutter 35 and a shutter driving means 38 for driving the shutter 35.

The shutter plate 31 is provided as a conductor plate having a larger area than the wafer A, and is coupled to the upper surface of the wafer holder 20. Then, the shutter plate 31 has a shutter plate 31 when the wafer loading bar 41 of the wafer transfer arm 40, which will be described later, moves up and down the transfer arm flow space 21 in the upper region of the wafer holder 20. Feed arm lifting slit 33 is formed to pass through. The transfer arm lifting slit 33 is open from the center area of the shutter plate 31 toward the station holder 10 side and corresponds to the wafer loading bar 41 of the wafer transfer arm 40 which will be described later. Are formed in pairs spaced apart from each other in parallel.

Here, the shutter plate 31 is preferably a relatively thin metal plate as the conductor, in particular, it is more preferable to use a stainless plate of 0.3mm to 1mm thickness to prevent the magnetization phenomenon.

In addition, the shutter 35 is opened and closed at the lower surface of the shutter plate 31 to block the transfer arm lifting slit 33 by driving a shutter driving means 38 such as a shutter driving motor or a shutter driver. It is installed to reciprocate to a position. The shutter 35 may be a structure having a pair of opening and closing plates 37 corresponding to the transfer arm lifting and slit 33 of the shutter plate 31, or may be a structure having a single opening and closing plate. At this time, at least the opening and closing plate 37 of the shutter 35 has an area capable of completely blocking the transfer arm lifting slit 33 of the shutter plate 31. This shutter 35 is also preferably provided with a stainless plate as one of the metal plates as the conductors.

On the other hand, while the wafer transfer arm 40 reciprocates to both sides of the wafer holder 20 and the station holder 10 by the rotational drive of the transfer arm driver 43, the wafer holder is rotated by the transfer arm driver 43. (20) and the station holder 10 to move up and down.

At this time, a wafer loading bar 41 is formed in the free end region of the wafer transfer arm 40 so as to lift the wafer A loaded on the wafer holder 20 and the station holder 10. The wafer loading bar 41 has a pair of bars corresponding to the transfer arm lifting slit 33 while having an outer diameter that allows the transfer arm lifting slit 33 of the shutter plate 31 to pass in the vertical direction. The wafer A is stably loaded and transported.

With this configuration, the wafer transfer process of the wafer transfer device 1 of the wafer inspection system using the electron microscope according to the present invention will be described with reference to FIGS. 6 to 8.

First, before the wafer A is supplied from the cassette table 130 to the station holder 10, the wafer transfer arm 40 is positioned in the transfer arm waiting space 11 of the station holder 10.

In this state, as shown in FIG. 6, when the wafer A supplied from the cassette table 130 is loaded on the upper surface of the station holder 10, the wafer transfer arm 40 is a transfer arm waiting space of the station holder 10. The wafer A is lifted while rising from (11).

Then, the wafer transfer arm 40 descends to the transfer arm flow space 21 of the wafer holder 20 while the wafer transfer arm 40 moves to the upper region of the wafer holder 20 by the rotational drive of the transfer arm driver 43. As shown in FIG. 7, the wafer A is mounted on the upper surface of the shutter plate 31 of the wafer holder 20. At this time, the shutter 35 is in a state where the transfer arm lifting slit 33 of the shutter plate 31 is opened. As a result, the wafer loading bar 41 of the wafer transfer arm 40 on which the wafer A is loaded descends through the transfer arm lifting slit 33 of the shutter plate 31, thereby shuttering the wafer A. Stable to the upper surface of the plate 31.

When the wafer A is loaded on the shutter plate 31 of the wafer holder 20, as shown in FIG. 8, the wafer holder 20 is driven from the wafer transfer chamber 150 by the driving of the wafer holder driver 23. The wafer transfer arm 40 naturally exits to the outside of the wafer holder 20 through the transfer arm flow space 21 of the wafer holder 20 in this process. At this time, the shutter 35 blocks the transfer arm lifting slit 33 of the shutter plate 31.

On the other hand, when the inspection of the wafer A is completed in the main inspection chamber 120, the wafer holder 20 is driven from the main inspection chamber 120 by the driving of the wafer holder driver 23, as shown in FIG. It is drawn out to the transfer chamber 150. At this time, the wafer transfer arm 40 is naturally positioned below the shutter plate 31 of the wafer holder 20 through the transfer arm flow space 21 of the wafer holder 20. In addition, the shutter 35 opens the transfer arm lifting slit 33 of the shutter plate 31.

In this state, when the wafer transfer arm 40 is raised, the wafer loading bar 41 of the wafer transfer arm 40 passes through the transfer arm lifting slit 33 of the shutter plate 31 to lift the wafer A. Lift it up. Then, while the wafer transfer arm 40 moves to the station holder 10, the wafer transfer arm 40 descends to the transfer arm flow space 21 of the station holder 10, and as shown in FIG. 6, the wafer A is transferred to the station holder 10. ) On the top surface.

The wafer A loaded on the station holder 10 in the state of being inspected is discharged to the cassette table 130 by the wafer discharge means 160 (not shown).

On the other hand, the wafer transfer device 1 of the wafer inspection system using the electron microscope according to the present invention is uniform in all areas of the wafer A in the process of inspecting the non-conductive wafer A such as sapphire wafer and gallium arsenide wafer. A distribution of electrons is made.

As shown in FIG. 9, since the negative electric field hung on the shutter plate 31 and the shutter 35 through the wafer holder 20 extends to the surface of the non-conductive wafer A, it has the same polarity as this negative electric field. Electrons of the electron beam scanned from the prominent electron microscope 110 are uniformly distributed over the entire area of the insulator wafer A which is in full contact with the shutter plate 31. At this time, since the area of the transfer arm lifting slit 33 formed on the shutter plate 31 is also blocked by the shutter 35, the electron distribution is uniformly formed even in this area.

As a result, electrons of the electron beam uniformly distributed over the entire area of the non-conductive wafer A form secondary signals uniformly over the entire area of the surface of the non-conductive wafer A, thereby accurately producing an image on the electron microscope 110. Thereby, the inspection of the nonconductive wafer A is also performed correctly.

In addition, in the wafer transfer apparatus 1 of the wafer inspection system using the electron microscope according to the present invention, the shutter plate 31 is provided on the wafer holder 20 so that the wafer A is entirely on the shutter plate 31. Since the wafer holder 20 moves between the main inspection chamber 120 and the wafer transfer chamber 150, there is no fear that the wafer A may flow or move away from the wafer holder 20. Thereby, the wafer A can be conveyed stably.

As described above, the wafer transfer apparatus of the wafer inspection system using the electron microscope according to the present invention can accurately perform the inspection of the nonconductive wafer, and can stably transfer the wafer.

1 is a schematic perspective view of a wafer inspection system using an electron microscope,

2 is a perspective view of a wafer transfer apparatus installation area of a wafer inspection system using a conventional electron microscope;

3 is a schematic view showing an inspection state of a non-conductive wafer loaded on a wafer holder of a conventional wafer transfer apparatus;

4 is a perspective view of a wafer transfer device installation area of a wafer inspection system using an electron microscope according to the present invention;

5 is an exploded perspective view of a wafer holder and a shutter plate unit of the wafer transfer device according to the present invention;

6 to 8 is a plan view of the wafer transfer device operating state of FIG.

9 is a schematic view showing an inspection state of a non-conductive wafer loaded on a wafer holder of the wafer transfer device according to the present invention.

* Explanation of symbols for the main parts of the drawings

 1: wafer transfer device 10: station holder

20: wafer holder 21: transfer arm flow space

30: shutter plate unit 31: shutter plate

33: transfer arm lifting slit 35: shutter

40: wafer transfer arm 41: wafer loading bar

Claims (4)

Electron microscope having a wafer holder in which the electron microscope enters the installation area and is formed with a transfer arm flow space stepped from the upper surface to the bottom, and a wafer transfer arm which transfers and loads the wafer from the outside to the wafer holder by moving and lifting driving. In the wafer transfer apparatus of the wafer inspection system using A shutter plate which is formed of a metal plate having a larger area than the wafer, is coupled to an upper surface of the wafer holder, and has at least one pair of transfer arm lifting slits that are opened outward from the center of the transfer arm flow space from a central region; To; The wafer transfer arm is a wafer transfer device of the wafer inspection system using an electron microscope, characterized in that a wafer loading bar corresponding to the transfer arm lifting slit is formed at the free end to move up and down through the transfer arm lifting slit. The method of claim 1, A wafer conveying apparatus of a wafer inspection system using an electron microscope, characterized in that a shutter made of a metal for opening and closing a transfer arm lifting slit is provided under the shutter plate. The method of claim 2, Shutter plate and the shutter is a wafer transfer device of the wafer inspection system using an electron microscope, characterized in that provided by a stainless plate. The method of claim 2, The wafer transfer device of the wafer inspection system using an electron microscope, characterized in that the shutter plate and the shutter has a thickness of 0.3mm to 1mm.

Images