JPH0346221A - Charged particle beam exposure device - Google Patents

Abstract

PURPOSE:To remove an adhered matter by reacting it with the adhered matter located on the inner wall of a lens barrel by a method wherein, after the cleaning gas introduced from a gas introducing part has been brought into a plasmic state between a pair of electrodes, the plasmic gas in introduced into the lens barrel of a charged particle beam exposure device. CONSTITUTION:Oxygen-containing gas is fed from outside through a flexible cylindrical tube 23, and on the other hane, the inside pressure of 0.01Torr is maintained by evacuating a lens barrel through a discharge hole 20. Also, the power of 50W having the frequency of 500kHz is applied to a pair of electrodes 22a and 22b, electricity is discharged, and the gas introduced into a lens barrel 15 from a gas lead-out part 21c is brought into a plasmic state. At this time, the ions in the plasma are concentrated along the line of magnetic force located in the vicinity of the magnet 22c attached to the tip of the electrode 22a. As a result, the adhered matter on the surface of the inner wall of the lens barrel 15 can be removed without directly giving damage to the inner surface by the bombardment of ions.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a charged particle beam exposure device, and aims to remove deposits on the inner wall of the lens barrel without damaging the lens barrel, and includes a gas introduction part, a gas conduction part, and a gas outlet. The gas is introduced from the gas introduction part and passes through the gas conduction part. After the cleaning gas led out from the gas outlet is turned into plasma between the pair of electrodes, it is sent into the lens barrel of the charged particle beam exposure device and reacts with deposits on the inner wall of the lens barrel to remove the deposits. A charged particle beam exposure apparatus includes a cleaning jig, and is configured such that a magnet is provided on one or both of the pair of electrodes.

[Industrial application field]

The present invention relates to a jig for cleaning a charged particle beam exposure apparatus.

In recent years, as ICs have become faster and more dense, exposure methods using charged particle beams, such as electron beam exposure methods, have come to be used in place of conventional photolithography to form circuit patterns. With this method, there is no need to create a reticle or mask (and the pattern can be formed by directly controlling the electron beam using computer-processed pattern design data, so the turnaround is fast. However, in order to actually expose a fine pattern on the order of submicrons at an accurate position using this method, it is necessary to obtain a stable electron beam with little change over time.

[Conventional technology]

FIG. 3 shows a sectional view of the main parts of the electron beam exposure apparatus. In the figure, an electron beam 12 emitted from an electron gun 11 passes through a lens barrel 15 in which a lens system 13, a deflection system 14, etc. are housed, enters a sample chamber 16, and enters a sample chamber 16.
The photoresist reaches the top and exposes the resist film coated thereon to form a resist pattern. The sample 17 to be exposed is fixed to a stage 18 that is movable in vertical and horizontal directions, and its position is controlled.

The electron beam exposure apparatus consists of many other control parts, and all these parts are housed in a housing 19, and the inside thereof is evacuated through an exhaust port 20 and maintained at a high vacuum. The position where the electron beam 12 irradiates the sample 17 to be exposed is determined by transmitting pattern design data prepared in advance to the lens system 13 and deflection system 14 from outside through an amplifier or DAC.
control by giving

Incidentally, there is a deviation inherent to the device at the irradiation position of the electron beam due to aberrations, distortions, etc. of the lens system. Therefore, before irradiating the sample to be exposed, the deviation of the irradiation position is experimentally obtained to create correction data, which is added to the pattern design data described above and used as the exposure data actually given to the apparatus.

However, as the device continues to be used, the irradiation position of the electron beam begins to shift again. This is caused by residual gas in the lens barrel when the electron beam passes through the lens barrel, organic components that volatilize from grease used in the joints of the lens barrel, and resists that are scattered by the electron beam irradiation. This is caused by adhesion to the inner wall of the lens barrel. Such deposits are then charged up by the electron beam passing through the lens barrel, and the charge accumulated in that portion exerts a force on the electron beam, causing a shift in the irradiation position. In particular, as shown by the dotted line in the figure, a large amount of resist scatters and deposits accumulate on the inner wall of the lens barrel near the sample to be exposed, which greatly affects the deviation of the irradiation position of the electron beam. Conventionally, when using a device, the amount of deviation was corrected by changing the correction data every certain time of use.
As the amount of deposits increases, the amount of deviation also increases, making it difficult to accurately correct the irradiation position using only correction data.

Therefore, in order to remove the deposits on the inner wall of the lens barrel, it is necessary to periodically overhaul the device, that is, perform decontamination cleaning.

However, it takes a lot of effort and time to clean equipment that requires a high degree of vacuum and consists of a complex combination of many parts.
This causes a decrease in the operating rate of the equipment. Therefore, it is desirable to remove the deposits on the inner wall of the lens barrel without disassembling the device.

FIG. 4 is a sectional view for explaining an example of such a method, and the same parts as in FIG. 3 are given the same numbers. This figure shows the cleaning jig inserted into the lens barrel 15 from the sample chamber 16.

This cleaning jig consists of an electrode 22 and an electrode support rod 21e connected to the electrode 22, and is fixed to a fixing table (not shown) in the sample chamber, and externally by passing a cable 24 from the other end of the electrode support rod 21e. It is connected to the high frequency power supply 25 of. A cleaning gas containing oxygen is flowed into the lens barrel 15 through a gas inlet (not shown) and the high frequency power source 2
When high frequency power is supplied from 5, a discharge occurs between the electrode 22 and the inner wall of the lens barrel 15, and the cleaning gas is turned into plasma. The cleaning gas turned into plasma reacts with deposits on the inner wall of the lens barrel and is exhausted from the exhaust port 20.

[Problem to be solved by the invention]

However, in the above method, a discharge is generated between the electrode at the tip of the cleaning jig and the inner wall of the lens barrel, so the inner wall of the lens barrel is directly sputtered and damaged by ions in the plasma generated near the inner wall of the lens barrel. For example, there were problems such as the plating on the inner wall surface of the lens barrel turning black.

Therefore, an object of the present invention is to remove the deposits from the inner wall of the lens barrel without damaging the lens barrel.

[Means to solve the problem]

The solution to the above problem consists of a cylinder equipped with a gas introduction part, a gas conduction part, and a gas outlet part, a pair of electrodes arranged at the tip of the gas outlet part, and a power supply device to the pair of electrodes. , a cleaning gas introduced from the gas inlet, passed through the gas conduction part, and led out from the gas outlet is turned into plasma between the pair of electrodes, and then sent into a lens barrel of a charged particle beam exposure apparatus; A charged particle beam exposure apparatus having a cleaning jig that reacts with deposits on an inner wall to remove the deposits, characterized in that one or both of the pair of electrodes is provided with a magnet. This is achieved using a charged particle beam exposure system.

[For production]

Magnets provided on one or both of the pair of electrodes concentrate lines of magnetic force near the electrodes. Therefore, when plasma is formed by applying power between the pair of electrodes, the generated ions are confined along the lines of magnetic force and do not directly sputter the inner wall of the lens barrel. Therefore, it is possible to remove deposits on the inner wall of the lens barrel without damaging the inner wall of the lens barrel by ions.

〔Example〕

FIG. 1 is a sectional view of main parts showing an embodiment of the present invention, and FIG.
Items that are the same as those in the figure are given the same numbers.

This figure shows a state in which a cleaning jig is installed in a sample chamber 16 of an electron beam exposure apparatus and inserted into a lens barrel 15 using an elevating mechanism. In the figure, the cleaning jig has a cylinder 21 having a gas introduction part 21a, a gas conduction part 21b, and a gas outlet part 21c, and a pair of electrodes 22a and 22b are provided at the tip of the gas outlet part 21c. . A magnet 22c is attached to the electrode 22a, and the magnet 22c is supported and fixed to the tip of the gas outlet portion 21c by an insulator 27. Further, a cable 22d is connected to the electrode 22a.
It is connected to the. The electrode 22b is electrically connected and fixed to the cylinder 21 by the electrode support frame 28, and faces the electrode 22a. On the other hand, the gas introduction part 21a is a flexible cylindrical pipe 2.
The cable 24 is connected to the cable 2 and drawn out of the housing 19 and passes through the center of the flexible cylindrical tube 23.
2d and externally connected to a high frequency power source 25. The lifting mechanism for inserting the cleaning jig into the lens barrel 15 includes a fixed base 30, a fixed base support frame 31, a pole screw 32, a bevel gear 33, a pulse motor 34, and a cleaning jig fixing frame 35. The fixed base 30
The cylinder 21 fixed to the cleaning jig fixing frame 35 is moved up and down by rotating the bevel gear 33 at the tip of the ball screw 32 attached through the fixing base support frame 31 by the pulse motor 34. It moves up and down.

To the cleaning jig configured as described above, a gas containing oxygen is sent from the outside through the flexible cylindrical tube 23, while the inside of the lens barrel is exhausted from the exhaust port 2o to maintain the internal pressure at 0.01 Torr. do.

In addition, a pair of electrodes 22a and 22b have a frequency of 500 KH.
z, apply a power of 50W and discharge it to the gas outlet part 2.
The gas led out from 1c into the lens barrel 15 is turned into plasma.

At this time, the ions in the plasma are concentrated along the magnetic field lines near the magnet 22c attached to the tip of the electrode 22a, so the inner wall of the lens barrel 15 is not directly damaged by the ion collision, and the deposits on its surface are removed. removed.

In addition to the electrodes shown in the above embodiments, electrodes having a shape as shown in FIG. 2, for example, can be used as the pair of electrodes provided in the gas outlet section. That is, opposing electrodes 22a and 22b as shown in the figure are provided at the tip of a cylinder 21 equipped with a gas introduction part, a gas conduction part, and a gas outlet part, and the 'magnet 22
Electric power is supplied from the outside to one electrode 22a attached to the electrode 22a along the outside of the cylinder 21 through a cable 22d insulated from the cylinder 21, and discharge is caused between it and the electrode 22b.

It goes without saying that the cleaning jig according to the present invention can be used not only for electron beam exposure apparatuses but also for charged particle beam exposure apparatuses such as ion beams.

〔Effect of the invention〕

As described above, according to the present invention, deposits on the inner wall of the lens barrel can be quickly and effectively removed without disassembling the device and without damaging the lens barrel, thereby increasing the reliability of the device. It is beneficial for improving operation rate.

[Brief explanation of drawings]

1st. Figure 2 is a sectional view showing an embodiment of the present invention, Figure 3 is a sectional view showing an embodiment of the present invention.
4 are cross-sectional views showing problems in the conventional example. In the figure, 11 is an electron gun, 12 is an electron beam, 13 is a lens system, 14 is a deflection system, 15 is a lens barrel, 16 is a sample chamber, 17 is a sample to be exposed, 18 is a stage, 19 is a housing, and 20 is a Exhaust port, 21 is a cylinder, 21a is a gas introduction part, 21b is a gas conduction part, 21c is a gas outlet part, 21e is an electrode support rod, 22. 22a, 22b are electrodes, 22c is a magnet, 22d, 24 are cables, 23 25 is a flexible cylinder, 25 is a high frequency power supply, 27 is an insulator, 28 is an electrode support frame, 30 is a fixed base, 31 is a fixed base support frame, 32 is a ball screw, 33 is a bevel gear, 34 is a pulse motor, and 35 is a cleaning This is the jig fixing frame. *eaM's @iFIKM4#aa Tomi 1 Figure 2Fee@'s fruitful 1Q I sequence ゛Σ, Tet V? Menpuko Figure 1 Conventional middle layer point Σ not shown Cross-sectional view Closed

Claims (1)

[Claims] A cylinder (21) equipped with a gas introduction part (21a), a gas conduction part (21b), and a gas outlet part (21c), and a pair of cylinders arranged at the tip of the gas outlet part (21c). Electrode (22a,
22b) and a power supply device to the pair of electrodes, which is introduced from the gas introduction part (21a) and connected to the gas conduction part (21a).
The cleaning gas led out from the gas outlet (21c) through 21b) is turned into plasma between the pair of electrodes, and then sent into the lens barrel (15) of the charged particle beam exposure apparatus to remove deposits on the inner wall of the lens barrel. A charged particle beam exposure apparatus having a cleaning jig adapted to remove the deposits by reacting with the charged particle beam, characterized in that a magnet (22c) is provided on one or both of the pair of electrodes. charged particle beam exposure equipment.