JPS59104127A - Formation of fine pattern - Google Patents

Abstract

PURPOSE:To contrive to enhance sensitivity to an electron beam and X rays, and to contrive to enhance productivity of a fine pattern by a method wherein a heat-treating process is executed at the middle between a high energy beam irradiating process and a developing process. CONSTITUTION:A resist solution is coated on a substrate 2, and then, drying by heating is performed to form a resist film 1. A high energy beam 3 is radiated on the resist film 1 to draw a pattern, and moreover, the sample is heat- treated. Then by performing development using a developer, a fine pattern is formed. When rebonding is thermally checked completely, and a reaction according to irradiation of the high energy beam is utilized to the maximum in such a way, sensitivity can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving sensitivity according to the #2 fine pattern forming method.

Figure 1 shows a conventional method for forming fine patterns. (4) Resist melting is performed on substrates such as silicon and glass (Q)
Using a Subinfuta, spin coat the top and continue with -co.
Heat and dry the G family (bribake) L'1: Completely remove the solvent L'C.

A resist film (1) is formed. A fine pattern is drawn by irradiating the coating with high energy beams of Bl. Next.

In C), using the current i'JL K, a phenomenon treatment is performed by a sinking method or a spray method to form a fine pattern.

The positive-shaped resist is developed by utilizing the difference in dissolution rate in the solvent between the part that has been irradiated with high-energy radiation and has a low molecular value, and the original part of the polymer that has not been irradiated with energy rays. , a fine pattern is formed.

Therefore, as a method of increasing the sensitivity of the positive type resist, there is a method of increasing the developing conditions. However, in this method, if the developing conditions are too strong, the high-energy beam-unirradiated area that should be left will dissolve, peel, or deform, making it impossible to significantly improve sensitivity.

The FBM resist represented by the structural formula, which is a positive resist for high energy beams with the highest sensitivity;

For the coelectric resist of FBM and glycidyl methacrylate represented by the structural formula, by optimizing the development conditions, the electron beam sensitivity was 0.4μC/ct/
l, X W sensitivity (M@-L line, wavelength = 5.4 A
) 35mJ/1 is obtained.

Even with this resist, it is impossible to increase the sensitivity any further by increasing the development conditions.

CH.

÷cHt − C 1 sho n (1) C=O ■ CH* CF t CHFCF * 'il'H・7H・ The present invention provides high energy ray sensitivity of FBM resists and copolymer resists of FBM and glycidyl methacrylate. After high-energy radiation irradiation with the aim of increasing

By heat-treating in the development step (■), high sensitivity can be easily achieved without reducing pattern accuracy.

High sensitivity is an important technology (B) for achieving high productivity and low cost in the production of large capacity, high density devices using high energy beam phosphorography.

FIG. 2 shows a pattern forming process according to the method of the present invention. In (4), the resist solution is coated on the substrate (2) using a Subino coater, and then the solvent is completely evaporated by heating and drying to form a resist film (1). Then, in (B), a high energy edge (3) is irradiated onto the resist film to draw a pattern rJI7L.

Then, the sample is heat-treated (interbaked) (C1
゜Next, a fine pattern is formed by developing using a liquid solution or a soufflé method (used for drawing the Dl pattern. Commercial energy beams include electron beams, soft X-rays, etc.). , far ultraviolet light (wavelength, 200-30
0 nm) can be used.

As a developer, in a resist film consisting of FBM and a co-coupled resist of FBM and glyc/dyl methacrylate, the areas where the low molecular weight has swollen due to high-energy edge irradiation and the areas where high-energy beams are not irradiated are used. In the original polymer site. Solvents whose dissolution rates differ significantly are used. As these solvents.

Preferred are methyl isoptyl getone (MiBK),
It is a liquid mixture whose main components are insolopanol (IPA) and insolopanol (IPA).

The developing temperature and mixing ratio will melt and deform the resist in the unirradiated areas.

It may be determined as appropriate so that there is no peeling.

Finally, the desired pattern is obtained by drying the sample.

The present invention is characterized in that an intervening step is added to the conventional method. The action of this interrupter will be explained.

The resist decomposes into low-molecular weight residues when irradiated with high-energy radiation, but some resists do not completely decompose due to recombination immediately after being cut. The recombined portion of L is thermally unstable, and complete single molecule cleavage is achieved by heating. The point of interest in carrying out the interbake step of the present invention is to improve sensitivity by completely thermally cutting off this recombination and making maximum use of the reaction caused by high-energy ray irradiation.

Example 1 Copolymer resist of FBM and glycidyl methacrylate (using spin coating method on all silicon wafers)
The resist film is coated, then heated at a temperature of 200° C. for 60 minutes to evaporate the solvent, and then cooled to room temperature to form a resist film. Next, using an electron beam drawing device,
Accelerating the electron beam onto the resist film at a voltage of 20 KV,
The irradiation dose ranged from 0.1μC/- to 3μC/-,
Expose for 40 steps. Next, in order to increase the electron beam sensitivity of the resist, the sample is heat-treated (interbaked) at 100° C. for 30 minutes in an air atmosphere. Next IC,
Methylated chilktone (MI BK) and isopropanol (IPA) mixed solution (mixing ratio = 1.25/I D
The solution temperature was kept constant at 22.5° C. and developed for 2 minutes using O). Then, rinse with isosopanol solution for 1 minute and then with n-butanol solution for 2 minutes.

Finally, blow nitrogen gas or air to dry the sample. The thickness of the developed resist film of the sample after drying is determined by MI using a film thickness measuring device such as Cristeso.

Figure 3 shows the electron beam sensitivity, i! The relationship between the irradiation density and the developed resist film thickness is shown. As shown in Figure 3, Curve 4 (in the conventional method without interbaking,
G-ray sensitivity is 0. <SμC/-, but the same figure 1 curve 5
The electron beam sensitivity obtained by implementing the intervator of the present invention was 0.24 μC/D11, indicating an approximately 2.5 times improvement in sensitivity.

Example 2 The process is the same as Example 1 except for the resist and developer mixing ratio. The resist uses FBM and is coated on a silicon wafer, heat treated at 200°C for 60 minutes (solibake), exposed to an electron beam, heated at 100°C for 50 minutes (interbake), and then developed. Process to form a #fine pattern. The developer is MIBK and I.
A mixed solution with a PA mixing ratio of 1:150 is used. The development processing method is the same as in Example 1. Figure 4 shows FBM
This shows the electron beam sensitivity characteristics of the resist. As shown in curve 4 of FIG. 4, the electron beam sensitivity of the conventional sample without interbaking is 0.98 μCIcdl. The electron beam sensitivity of the sample subjected to the interbaking of the present invention, shown by curve 5 in FIG. 1, was 6 μCAt1l, indicating that interbaking improves the electron beam sensitivity of the FBM resist.

Example 3 Even if soft X-rays are used as high-energy rays, 1! The same effect as the child line can be obtained. In the same manner as in Example 1, a copolymer resist of FBM and glycidyl methacrylate is formed on a silicon substrate. Next, a molybdenum target (wavelength: 5
．． 4X) to irradiate with high-energy radiation. At this time, the input voltage was 17 KV and the current was 830 mA.

The irradiation energy is controlled by using a shutter and varying the irradiation time. Interbaking and development methods after soft X-ray irradiation are performed in the same manner as in Example 1. When intervening is not used, a resist film thickness of 0.7 μm is removed. Irradiation time is 2 minutes (irradiation energy s 55 m
J/cA). on the other hand.

In the case of interbaking, the irradiation time is 50 seconds (irradiation energy: , 14 mJAyrJ), which means that the irradiation energy per irradiation time is small, indicating that the sensitivity is improved. Increasing the resist sensitivity is particularly effective in X-ray exposure where the X-ray output is small and productivity is low.

Example 4 Even when the FBM resist was irradiated with soft X-rays (wavelength: 5.4t), the same interbake effect as in Example 6 was obtained by 3.
). The soft X-ray irradiation method was performed in the same manner as in Example 3, and the development method was performed in the same manner as in Example 2. The irradiation energy for removing a 0.7 μm resist without interbaking is 60 mJ/cy/1. On the other hand, if you intervene.

The irradiation energy is reduced to 37 mJ/cd, indicating that the sensitivity is the same as above.

Example 5 Far ultraviolet rays (wavelength: 200-300
There is also an effect of interbake when using nanometer (nm).

A 30W deuterium lamp is used as the continuous external radiation source, and 2
A high energy beam is irradiated onto the 8M resist film. The resist coating, bending, interbake, and current counting method are the same as in Example 2. If you don't interact.

It is necessary to remove 0.7 μm of resist. The irradiation energy of the deuterium lamp is 100mJ/c++! It is.
On the other hand, when interbaking is performed, the irradiation energy is as small as 60 mJ/-, indicating that the sensitivity is improved.

As explained above, an FBM resist and a copolymer resist of FBM and glycidyl methacrylate are used.

In the method of forming fine patterns, it can be easily inferred that a positive resist for high-energy radiation, which exhibits the same effects as exposure and development processing, has similar effects.

Increasing the sensitivity of electron beams and X-rays has the advantage of improving productivity, which is most important in the production of large-capacity wiping and high-density devices.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for forming a fine pattern according to a conventional method, and FIG. 2 is a process diagram for forming a fine pattern according to the present invention. FIG. 3 is an electron beam sensitivity characteristic diagram of a copolymer resist of FBM and glycidyl methacrylate, and FIG. 4 is an electron beam sensitivity characteristic diagram of an FBM resist. 1...Resist 2 River substrate 3...U energy line 4...Interbake L5. ...Interbaking (91-121 Third Edict C line @ placement (7) Figure 1 Procedural Amendment 4 (voluntary submission) March 1981 Mr. Aio Wakasugi, Commissioner of the Japan Patent Office 1 Indication of the case Japanese Patent Application No. 57-21341, Relationship with the case of the Ministry of the Ministry of Health, Labor and Welfare to amend the method for forming fine patterns on the base of the invention 3 (422) Nippon Kameshin' Ginko Corporation 4 agent 5 correction against acid "Figure 3 is a diagram showing the relationship between interbaking mlf and electron ballistic sensitivity.The interbaking temperature is 100°0.
150°C 2200°0 The button is high, so the sensitivity is also high. However, when the temperature exceeds 150°C, 2μC/11
1 at a low electron beam dose of n! The child beam is irradiated,
Resist remains in the areas to be removed. A so-called negative reversal occurs. (2) On page 6, lines 4 and 5, and on page 9, line 12, ``Figure 3'' is corrected to ``Figure 4.'' (3) No. 6, lines 18 and 19, page 9, line 14 “
"Figure 4" is corrected to "Figure 5." (4) Insert the following sentence after the 9th negative 12th line "-It is a one-anal phase diagram." [FIG. 6 is a diagram showing the relationship between interbake temperature and electron beam sensitivity. (5) Drawing As shown in the attached sheet, the whistle Ig 0 50 too l da 0
200 Interbekushi Ran 2 Ha ((υ Rod 3 Figure 4 Hayabusa button

Claims (1)

[Claims] A method for forming a fine pattern in a positive resist for high-energy beam photography, characterized in that a heat treatment step (interverter) is performed between a high-energy field irradiation step and a development step.