JPH04247616A - Dry development method - Google Patents

Abstract

PURPOSE:To prevent deposit from depositing in a reaction system by developing a resist film in downflow of plasma generated by using mixture gas containing specific elements. CONSTITUTION:Mixture gas of oxygen and nitride trifluoride (NF3) is used as gas to be used for generating plasma. An apparatus comprises a microwave oscillator 1, a stab tuner 2, a cooling water inlet part 3, a waveguide 4, a microwave transmitting window 5, a plasma generation chamber 6, a side wall 7 made of aluminum, a gas inlet tube 8, a gas diffusion plate 9, a gas diffusion plate support rode 10, a substrate processing chamber 11, a substrate 12 to be processed, a susceptor 13, an exhaust port 14 and a susceptor vertically actuating mechanism 15. Since the length of the gas diffusion plate support rod 10 is as short as approximately 2mm, a slit above the gas diffusion plate 9 is narrow, so that the plasma is confined into above the gas diffusion plate 9. Therefore a stream below the gas diffusion plate 9 is downflow not containing charged particles.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry developing method using plasma downflow. In recent years, with the progress of higher integration and miniaturization of LSIs, there is a need for technology for forming fine resist patterns. The method of using a two-layer resist is effective in meeting such requirements, but in this case, it would be even more effective for miniaturization if the upper layer resist could also be developed in a dry process in addition to the lower layer resist.

The present invention can be used to develop such fine patterns.

0003

[Prior art] In the conventional down-flow development method,
For example, as described in Japanese Unexamined Patent Publication No. 2-2563 by the present applicant, plasma for generating downflow uses a mixed gas of oxygen and fluorocarbons such as carbon tetrafluoride (CF4). It was generated by irradiating it with microwaves.

[0004] The exposed wafer, on which a resist film has been deposited, is placed in the downflow, which is a region downstream of the generated plasma where ions and electrons have disappeared, and is developed. For this reason,
The active species in the downflow include only electrically neutral species such as oxygen radicals, and the resist containing organic components is etched.

Furthermore, by appropriately selecting the ratio of oxygen to fluorocarbon and the gas pressure, it was possible to pattern the resist with a high residual film ratio (film thickness after development/film thickness before development).

[0006]

[Problem to be solved by the invention] However, in the conventional downflow development method, fluorocarbons such as CF4,
In other words, a large amount of carbon-containing gas was used, accounting for 1/3 of the total flow rate.

[0007] Therefore, a fluorocarbon film is formed on the window portion through which microwaves for generating plasma are introduced, and this film peels off, causing dust generation. Another problem was that optimizing the developing device to improve the development distribution significantly reduced the development speed, making it impractical.

In an apparatus with a poor development distribution before optimization, the gas flow rate at the wafer surface is extremely large, whereas in an optimized apparatus, the overall gas flow rate at the wafer surface is adjusted to improve the development distribution. It's getting slower. The ratio is less than 1/10.

An object of the present invention is to provide a downflow development method in which deposits that cause dust are not deposited in the reaction system and the development speed does not decrease even if the development device is optimized.

0010

[Means for solving the problem] The solution to the above problem is 1)
A dry development method in which the resist film is developed in a downflow of plasma generated using a mixed gas containing oxygen and nitrogen trifluoride, or 2) the resist film contains a polyacetylene derivative and an aromatic cycloadding agent. This is achieved by the dry developing method described in 1) above.

[0011]

[Operation] By using a mixed gas of oxygen and nitrogen trifluoride (NF3) as the gas used for plasma generation, the present invention enables dry development without introducing elements that cause deposits such as carbon into the reaction system. This is how it was done.

[0012] Furthermore, the reason why the development speed does not decrease even when the development device is optimized is presumed to be that when nitrogen trifluoride is used, the concentration of fluorine radicals generated increases and the etching reaction of the resist is carried out efficiently. Ru.

[0013]

Embodiment FIG. 1 is a sectional view of a developing device used in an embodiment of the present invention. In the figure, 1 is a microwave oscillator, 2
is a stub tuner, 3 is a cooling water introduction part, 4 is a waveguide, 5
is a microwave transmission window made of alumina, 6 is a plasma generation chamber, 7 is a side wall of the plasma generation chamber made of aluminum (Al), 8 is a gas introduction pipe, 9 is a gas diffusion plate made of Al, 10
11 is a support rod for the gas diffusion plate, 11 is a substrate processing chamber, 12 is a substrate to be processed, 13 is a susceptor, 14 is an exhaust port, 15
is the vertical movement mechanism of the susceptor.

[0014] Here, since the length of the support rod 10 of the gas diffusion plate is shortened to about 2 mm, the gap at the top of the gas diffusion plate 9 is narrowed, and therefore, the plasma is transmitted to the top of the gas diffusion plate 9. Limited.

Downstream from the gas diffusion plate 9, there is a downflow that does not contain charged particles. Next, an example of processing will be described. The host polymer PTMDSO (Poly 4
,4,7,7-tetramethyl-4,7-di
sila-2-octyne) and additive agent 3DAPM
(3,3'-Diazidedimethylmeth
A resist consisting of a xylene solution of 2:1 (weight ratio) with 2:1 (by weight) is applied onto the wafer (substrate).

Next, using a KrF excimer laser stepper, a pattern is exposed on the resist at 180 mJ/cm 2 . Thereafter, the wafer is subjected to reduced pressure heat treatment at 70° C. for 5 minutes.

Next, using the developing apparatus shown in FIG. 1, development is performed in a downflow of plasma under the following conditions to form a negative pattern. As a result, negative type L&S (lines and spaces) of 0.3 μm was resolved.

[0018] The development speed is 8300 Å/min,
This is a significant improvement over the conventional example of 70 Å/min. Also,
The residual film rate was 91%, which is a value that can be used for practical purposes. In the examples, PTMDSO was used as the polyacetylene derivative of the host polymer of the resist, but PTMDSH (Poly 4,4,6,6-tetr
amethyl-4,6-disila-2-hexy
ne) may also be used.

Furthermore, in the examples, 3DAPM was used as the aromatic ring-containing additive for the resist, but 4DAPM (4,4'-Diazide diph
enylmethane), 4DAPE (4,4'-
Diazide diphenylethene),
4DAPER (4,4'-Diazide diph
enylether) may also be used.

[0020]

[Effects of the Invention] A down-flow development method was obtained in which deposits that cause dust generation are not deposited in the reaction system, and the development speed does not decrease even if the development device is optimized.

As a result, it was possible to improve the yield and throughput of LSI manufacturing with fine patterns.

[Brief explanation of the drawing]

[Fig. 1] Cross-sectional view of a developing device used in an example of the present invention

[Explanation of symbols]

1 Microwave oscillator 2 Stub tuner 3 Cooling water introduction part 4 Waveguide 5 Microwave transmission window 6 Plasma generation chamber 7. Side wall of plasma generation chamber 8 Gas introduction pipe 9 Gas diffusion plate 10 Support rod for gas diffusion plate 11 Substrate processing room 12 Substrate to be processed 13 Susceptor 14 Exhaust port 15 Susceptor vertical movement mechanism

Claims (2)

[Claims] 1. A dry developing method characterized in that a resist film is developed in a downflow of plasma generated using a mixed gas containing oxygen and nitrogen trifluoride. 2. The dry developing method according to claim 1, wherein the resist film contains a polyacetylene derivative and an additive containing an aromatic ring.