JPH11162391A - Cleaning method for charged beam drawing lens-barrel, charged beam drawing lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clean inside of a charged beam drawing lens-barrel without disassembling it. SOLUTION: Ozon O3 is supplied from an O3 generating unit 22 to a charged beam drawing lens-barrel 10 through a constant delivery valve 23, and at the same time, the degree of vacuum inside the charged beam drawing lens-barrel 10 is maintained at 10<-3> -10<-5> Pa by ion pumps 18A, 18B, 18C, and the charged beam B is passed through the lens-barrel 10. The charged beam B collides with a surface of a member inside of the lens-barrel 10 and generates scattered electrons. These scattered electrons assists the compounding of the bumping material of the resist flowing into the charged beam drawing lens-barrel 10 and O3 at the time of drawing and O3 , and decomposes the bumping material. The decomposed bumping material of the resist is discharged to the outside by means of evacuation of the ion pumps 18A, 18B, 18C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged beam drawing column (hereinafter referred to as a mirror) for generating a charged beam and guiding the charged beam to a desired position on a material to be drawn having a surface coated with a resist. In particular, the present invention relates to a method for cleaning the inside of the lens barrel and a lens barrel for performing the method.

[0002]

2. Description of the Related Art Since the inside of a lens barrel is used in a high-vacuum environment, it is manufactured and controlled so as not to cause dirt. After flowing into the lens barrel, the dirt accumulates after one or two months of use, leading to deterioration of the position accuracy of the charged beam.
Therefore, it is necessary to periodically disassemble the lens barrel and clean the parts.

[0003]

By the way, the drawing accuracy has become more and more advanced, and as a result, the frequency of disassembly and cleaning of the lens barrel has been increased. Periodic disassembly and cleaning of the lens barrel not only lowers the operation rate of the apparatus, but also causes problems such as occurrence of trouble when the performance is restored after the disassembly and cleaning.

An object of the present invention is to provide a method for cleaning the inside of a charged-beam drawing barrel without disassembling the same, and a charged-beam drawing barrel for carrying out the method.

[0005]

According to the present invention, a charged beam is generated by generating a charged beam and guiding the charged beam to a desired position on a material to be drawn having a surface coated with a resist. A method for cleaning a beam writing column, comprising supplying O ₃ into the charged beam writing column and reducing the degree of vacuum in the charged beam writing column to 10
^-3 to ^10-5 Pa and pass the charged beam,
The bonding action between the bumps of the resist that has flowed into the charged-beam-drawing barrel and the O ₃ with the drawing is promoted by scattered electrons from the charged beam generated in the charged-beam-drawing barrel. Decomposes the bumped material, and discharges the decomposed bumped material to the outside by evacuation to keep the inside of the charged beam drawing column at a vacuum.

According to this method, the inside of the charged beam drawing barrel can be cleaned without disassembling. This cleaning can also be performed during drawing, and if performed during drawing, dirt inside the lens barrel can be prevented.

The present invention is also directed to a charged beam drawing method for generating a charged beam while maintaining the inside of the vacuum and guiding the charged beam to a desired position on a material to be drawn having a surface coated with a resist. in use barrel, it is provided with a means for supplying the O ₃ to the charged beam drawing lens barrel.

[0008] As the vacuum level in the charged particle beam drawing lens inner cylinder while supplying O ₃ from the means of a predetermined amount for supplying the O ₃ is 10 ^{@ 3} to 10 ^{over 5} Pa, perform vacuuming Thus, the above-described cleaning method can be performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Reference numeral 10 denotes a lens barrel, and reference numeral 30 denotes a drawing room. The lens barrel 10 includes a charged beam source 1 such as an electron gun.
1, lens 12, 13, 14, blanking electrode 15,
Consists deflector 16, 17, the barrel 10, an ion pump 18A as a vacuum pump, 18B, adapted to be evacuated to a vacuum degree of about 10 ^@ 5 Pa by 18C.

Reference numeral 19 denotes a vacuum pump such as a rotary pump used in an initial stage of evacuation, and the ion pump 1 is provided via vacuum valves 20A, 20B and 20C.
It is connected to the lens barrel 10 similarly to 8A, 18B and 18C. 21A, 21B and 21C are vacuum gauges.

Reference numeral 22 denotes an O ₃ generator, which supplies O ₃ to the inside of the lens barrel 10 via a fixed-rate discharge valve 23. FIG. 1 shows an example in which O ₃ is supplied to a portion of the lens barrel 10 where the deflectors 16 and 17 are most likely to be contaminated and the contaminants most affect the drawing accuracy. It goes without saying that it may be supplied to other parts.

A sample 31 as a material to be drawn is movably stored in a stage (not shown) in the drawing chamber 30. The inside of the drawing chamber 30 is controlled by an ion pump 32 as a vacuum pump in the same manner as the inside of the lens barrel 10. It is adapted to be evacuated to a vacuum degree of about 10 ^{@ 5} Pa to.

Next, the operation of the present apparatus will be described. O
_The lens barrel 10 from the _three generators 22 through the fixed amount discharge valve 23
While supplying O ₃ to the inside of the ion pump 18A,
18B, interior ^10-3 of the barrel 10 by 18C to 10
Keep the degree of vacuum of ^over 5 Pa.

In this state, a charged beam B is generated from the charged beam source 11. In the case where the charged beam source 11 _LaB 6 used (6 lanthanum fluoride), it is necessary to make the barrel 10 to 2 × 10 ^over 5 Pa level of vacuum, the flow rate of _{O 3} must be set to an extremely small amount, recently, CeB 6 become single crystals ₍₆ cerium fluoride) is used, 10 ^-3 According to this
Because even 10 ^{over 4} Pa level of vacuum can be used, it can be relatively large set the flow rate of O _3.

After passing through the lens 12, the passing / blocking of the charged beam B is controlled by the blanking electrode 15. The charged beam B that has passed through the blanking electrode 15 is
Further, the resist is guided to a desired position on the sample 31 through the lens 13, the deflectors 16, 17 and the lens 14, and the resist (not shown) applied on the surface of the sample 31 is exposed and drawn.

[0016] Along with this drawing, the vapor which evaporates from the resist flows into the lens barrel 10, adheres to the inner surface thereof, and is accumulated. This dirt is charged by the charged beam B and changes the position of the charged beam B. Of the inner surface of the lens barrel 10, the charged beam B
Of the deflectors 16 and 17 which receive the intensity change of the charged beam B due to ON / OFF of the passage of the beam and the deflection, the charged beam B
Greatly affects the deterioration of the position accuracy.

By the way, the O ₃ generator 2 is provided in the lens barrel 10.
2 O ₃ through the dispensing valve 23 is supplied from, and because some scattered electrons when such a deflector 16, 17 of the charged beam B is caused, O ₃ lens barrel 10 with the aid of the scattered electrons The bumping vapor from the resist flowing into the inside and the bumping substances already adhered to the inner surface of the lens barrel 10 are combined and decomposed as shown in the following chemical formulas (1) and (2), and are evacuated to the outside by evacuation. Let it drain.

CnHmOl + xO ₃ + e → nCO ₂ + (m / 2) H ₂ O + x′O ₂ + x ″ O ₃ (1) CnHmOl + e + O ₂ → nCO ₂ + (m / 2) H ₂ O + x′O ₂ (2)

This cleaning may be performed at the time of non-drawing, but can be performed at the time of drawing, so that it can be performed without lowering the operation rate of the apparatus.

[0020]

As described above, according to the present invention, it is possible to remove dirt in the lens barrel, which greatly affects the deterioration of the positional accuracy of the charged beam, without disassembling the lens barrel, and also to remove the dirt during writing. By supplying O ₃ to the substrate, adhesion of dirt can be prevented beforehand. This facilitates maintenance and management of the apparatus, reduces the occurrence of troubles due to disassembly and cleaning of the lens barrel, increases the operation rate of the apparatus, and at the same time facilitates maintenance of drawing accuracy. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Column 11 Charge beam generation source 12, 13, 14 Lens 15 Blanking electrode 16, 17 Deflector 18A, 18B, 18C Ion pump (vacuum pump) 19 Vacuum pump 20A, 20B, 20C Vacuum valve 21A, 21B, 21C Vacuum Total 22 O ₃ generator 23 Fixed amount discharge valve 30 Drawing room 31 Sample 32 Vacuum pump

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/027 H01L 21/30 541Z 551

Claims (3)

[Claims] 1. A method for cleaning a charged beam drawing barrel for generating a charged beam and guiding the charged beam to a desired position on a material to be drawn having a surface coated with a resist, the method comprising: While supplying O ₃ into the drawing barrel,
The degree of vacuum of the charged beam drawing lens inner cylinder 10 ^{over 3-10
The} charged beam is passed through the charged beam drawing column while maintaining the pressure at −5 Pa, and the bonding action between the bumps of the resist flowing into the charged beam drawing column and the O _{3 along} with the drawing is performed in the charged beam drawing column. The bumps are decomposed by being promoted by scattered electrons from the charged beam generated in the above, and the decomposed bumps are discharged to the outside by evacuation to keep the inside of the charged beam drawing barrel vacuum. Cleaning method for charged beam drawing column. 2. The method according to claim 1, wherein the cleaning is performed during writing. 3. A charged beam drawing column for generating a charged beam while maintaining a vacuum inside thereof and guiding the charged beam to a desired position on a material to be drawn having a resist coated on a surface thereof. , charged beam drawing barrel, characterized in that a means for supplying the O ₃ to the charged beam drawing lens barrel.