JPS60165723A - Forming method for fine pattern - Google Patents

Abstract

PURPOSE:To obtain a pattern by exposing in a mixture gas of raw material gas containing a raw material of a thin film to be accumulated and reactive gas containing halogen element, emitting a light to accumulate the thin film, and selectively emitting the prescribed energy beam in high vacuum. CONSTITUTION:An Si substrate 41, on which a SiO2 film 42 is superposed, is used as a sample 12, a mixture gas of Si(CH3)4 and Cl2 is fed into a vessel 11, an excimer laser light 18 is emitted to ionize the Cl2, to react it with the Si(CH3)4, thereby accumulating a thin organic film 43. The vessel 11 is evacuated, a light shielding material 46 is coated on a glass plate 45, and the film 43 is selectively emitted with the prescribed energy beam 21 through a mask plate 47 formed by coating the material 46 on the glass plate 45. The film 43 is exposed and developed by this emission to form a pattern of the mask 47. In this case, a light source 20 and the sample 12 are approached as near as possible. According to this configuration, the processing accuracy is more preferable than a method using liquid. The raw material gas uses Ge(CH3)4, Cd(CH3)2 or the other, a sensitizer Hg may be added and Hg exciting light may also be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fine pattern forming method for forming a mask pattern or the like on a thin film formed using a photochemical reaction.

[Technical background of the invention and its problems]

BACKGROUND ART In recent years, integrated circuits have become increasingly finer, and recently, prototypes of ultra-LSIs with a minimum pattern size of 1 to 2 [zzm] have been developed. In such microfabrication, an etching mask is usually formed on the sample to be processed, and the sample is selectively etched using reactive ion etching using this mask. An electron beam resist such as a resist material such as F-A1 or PMMA (polymethyl methacrylate-1.) is used. That is, a resist material dissolved in a solvent is applied to a wafer, baked and hardened, and then exposed to light, then immersed in a developer to form a mask pattern to form an etching mask, and then further baked and hardened for the next etching process. This is how we proceed.

However, this product method has the following problems. That is, in the current etching mask forming process, it is necessary to use a liquid processing agent, and when a liquid is used, the processing liquid may not be uniformly supplied to the fine pattern due to its surface tension.

For this reason, the finer the pattern to be formed, the lower the processing accuracy, and these processes are considered to be unsuitable for future submicron pattern formation. In addition, the series of processes such as resist coating → exposure → development → etching described above are important steps for forming the pattern of an integrated circuit.
This process requires a particularly high level of clean room to prevent pattern defects due to the adhesion of dust in the air.

As integrated circuits become increasingly finer, clean rooms are required to be even more dust-free, necessitating extremely expensive equipment. Furthermore, the electron beam resist currently used has low etching resistance as an etching mask, and a material that is resistant to etching is desired.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fine pattern forming method that can form a thin film that is the basis of an etching mask and its pattern without using a liquid processing agent, and can improve pattern processing accuracy.

[Summary of the invention]

The gist of the present invention is to form an organic thin film that is the basis of an etching mask using a photochemical reaction, and to form a desired pattern on the thin film by selective irradiation with an energy beam.

That is, the present invention provides a fine pattern forming method for forming an S film pattern serving as an etching mask on a sample substrate to be microfabricated, in which the substrate is mixed with a raw material gas containing a raw material for a thin film to be deposited on the substrate, and at least a halogen gas. A thin film is deposited on the substrate by a photochemical reaction by exposing it to a gas mixture with a reactive gas containing an element, irradiating the mixture gas with light, and then placing the substrate in a high vacuum. A predetermined energy beam is selectively irradiated onto the thin film on the KKljA plate according to the pattern to be formed on the substrate! )j 'l.

〔Effect of the invention〕

According to the present invention, the formation of a thin film that is the basis of an etching mask, and the steps of exposure and development can be performed continuously in a gas atmosphere or in a vacuum. can be improved. In addition, it is possible to shorten the process and reduce the number of limbs.
It is possible to save lean room. Therefore, it is possible to sufficiently cope with the future trend toward 1J micronization of integrated circuits.

It also has the advantage of being able to form an etching mask with excellent etching resistance.

[Embodiments of the invention]

First, before explaining the invention in detail, the experimental results that formed the basis of the present invention will be explained. The wafer deposited with silicon dioxide was mixed with chlorine and tetramethylsilane; (CH3)4
Si: placed in a mixed gas atmosphere with (TMS), and as shown in Figure 1 (a), the upper part of the wafer 1 is exposed to excimer laser light (XeC1, wavelength 308 nm, output 2 W).
/'cd)2 is passed parallel to the wafer 1 and the organic i11
! 3, the proportion of chlorine in the mixed gas and I'
The relationship with the cumulative velocity is shown in Figure 2. Here, the pressure of the mixed gas was 10 [torr]. As a result, it was found that the deposition rate reached its maximum value when the proportion of chlorine was 60 [v01%]@. Next, when the excimer laser beam 2 is directed perpendicularly to the beam 1 as shown in FIG.
11 vg's! FIG. 3 shows the relationship between the i11 ratio and the deposition rate. Here, the pressure of the mixed gas is 1Q[t
[orr] What's up? In this case, the deposition rate increased as the proportion of chlorine in the mixed gas decreased, that is, as the proportion of TMS increased. However, the 11-layer film with chlorine content of 45 [vo1%] has a very uneven surface and the chlorine eel is 70-□
With 〇〇 [vo1%], a more uniform film was obtained with better reproducibility. Furthermore, Figure 4 1 Ma IJ! Raw ratio 1:L85[
FIG. 4 is a characteristic diagram showing the relationship between the deposition rate and the mixed gas pressure when the wafer 1 is irradiated with light perpendicularly, with the VO fixed at 1%. As the pressure of the mixed gas increases, the JI deposition rate also increases, but in this case, the JI deposition rate formed at a high deposition rate of approximately 1000 [in/10] or more is inferior in uniformity, and the JI deposition rate is 10 to 50
A pressure of about [torr] is considered appropriate.

Next, the results of investigating the thermal characteristics of the organic WIIla deposited in this manner will be shown. Figure 5 shows 5000 [
FIG. 3 is a characteristic diagram showing the relationship between the temperature rise of the wafer and the decrease in the amount of the deposited film when a wafer to which a deposited film (III thin film) has been attached is heated in a vacuum. As the temperature rose, the deposited film evaporated and disappeared completely at about 110[° C.]. This suggests that when the deposited film is used as a resist, exposure and development can be performed simultaneously by selectively irradiating light or electron beams in a vacuum. Furthermore, Fig. 6 is a characteristic diagram showing the relationship between substrate concentration and deposition rate when a deposited film is formed by keeping the substrate at a specific temperature and passing light parallel to the substrate in the aforementioned mixed gas. be. A 9-peak exists around 50 [°C], and no deposition occurs at about 80 [°C]. From this, if you want to increase the Ji stacking speed, change the board to 5
It is preferable to control the temperature to about 0 [°C]. Also, locally 8
By heating to 0[° C.] or higher, no crotch is formed in that part, and selective Ti product becomes possible. Also, this j
In order to confirm the etching resistance of the Ti film, it was exposed to salt Ti radicals and fluorine radicals, which are typical etching species for semiconductor materials, and it was confirmed that there was no etching at all.

In addition, in experiments conducted by the present inventors, a small amount of mercury was added to a mixed gas of chlorine and TMS, and a low-pressure mercury lamp was used to emit light that excited the mercury. An attempt was made to increase the deposition rate by mercury sensitization by irradiation in combination with mercury sensitization. Figure 7 shows excimer laser light and 1 near the wafer.
This is the result of investigating the change in deposition rate with respect to the proportion of chlorine in the mixed gas when O lamp light was passed parallel to the wafer.

As can be seen from this figure, the deposition rate peaks when chlorine is contained at around 70 [vol%];
When the value was 0 [v01%], a flat thin film with good uniformity of 10- was obtained. Furthermore, compared to FIG. 2, it can be seen that the lfi product rate increases approximately twice by using the mercury sensitization method. FIG. 8 shows a bond in which the change in the jft bulk velocity with respect to the mixed gas pressure was investigated with the proportion of chlorine being 85 [v01%], similarly using the mercury sensitization method.

From the above experimental results, it is possible to form a TiTa film by irradiating light that dissociates chlorine in a mixed gas of chlorine and TMS, and this film has good etching resistance against etching species of halogen elements. It was found that while it has some properties, it evaporates when heated in a vacuum.

Therefore, it has become clear that it can be used as an etching mask that can form fine patterns by irradiating it with light, electrons, ions, etc. in a vacuum. Furthermore, in order to form such an organic thin film, it is possible to use not only a structure of chlorine and TMS but also a structure of a compound containing a CHa group, a compound containing hydrogen and carbon, and a reactive gas containing a halogen element. In this case, the light used to form the thin film ranges from ultraviolet to
You can choose from HA fa Ia. Similar results were also obtained using short wavelength light that directly excites organic compound gas such as VMS. Furthermore, 1((
It was also found that the stacking velocity could be increased.
.

Below, each example method to which the present invention is applied will be explained.

FIG. 9 is a schematic configuration diagram showing the apparatus used in the first embodiment of the present invention. In the figure, 11 is a vacuum container, and this container 11
A wafer boulder 13 on which a sample substrate 12 is placed is arranged inside. This holder 13 is moved in the vertical direction by a drive 1 and a lateral 14. Further, the container 11 is provided with a gas inlet 15 for introducing a source gas such as jMs and a reactive gas such as chlorine, and a gas exhaust port 16 for exhausting the gas inside the container 11.

On the other hand, on the left side of the container 11, a light source 17 for dissociating the above-mentioned reactive gas is arranged. This light source 17 has a wavelength included in the absorption spectrum of chlorine, approximately 330 [nm]
A device that generates nearby light, such as an excimer laser. The light 18 from the light source 17 is guided into the container 11 through a light passing window 19 provided on the side wall of the container 11, and is irradiated onto the mixed gas of the raw material gas and the reactive gas. It has become. Further, above the container 11, a light [20] for photo-etching is arranged. The light 21 from this light source 20 is transmitted to a mask (not shown) and a light passing window 22 (not shown).
The light is guided into the container 11 through the light beams, etc., and is irradiated vertically onto the substrate 12.

In the figure, 31 is a waste flow rate controller that controls the flow rate of the raw material gas, 32 is a gas flow rate controller that controls the flow of reactive gas, and 33 is a gas flow rate controller that controls the flow rate of the raw material gas. Goo 1 to valves for putting in and taking out the inside and outside are shown respectively.

Next, a method for forming a fine pattern using the iA1 described above will be explained. First, the sample substrate 12 is shown in FIG.
) As shown in <51 as a workpiece material on a Si wafer 41.
02 film 42 was used. Tetramethylsilane (TMS) was used as a raw material gas, and chlorine was used as a reactive gas, and these gases were introduced into the container 11. Next, ximer laser light 18 from the light source 17 was introduced into the container 1. As a result, the chlorine gas in the mixed gas is dissociated, and the chlorine radicals react with TMS, resulting in the reaction shown in Fig. 10(b).
As shown in FIG.

Next, after exhausting the gas in the container 11, the sample substrate 12 was patterned using light 21 from the light source 20. That is, as shown in FIG. 10(C), a mask substrate 47 is formed by attaching a mask material 46 to a quartz substrate 45.
143 was selectively irradiated with light 21. By this light irradiation, the organic thin film 43 was exposed and developed, and a pattern 44 of an etching mask was formed. In this exposure/development process, it is more effective to bring the light source and the sample substrate 12 as close as possible.

After the development is completed, test 1 is applied via the game valve 33.
1 This process is completed by taking out the substrate 12 to the outside, but the container 11 is taken out through this gate valve 33.
By connecting the culm to the next vacuum vessel, it is possible to carry out the entire series of 14- series of fine processing within the vacuum vessel.

As described above, according to this embodiment, the steps of forming the organic i%I film 43 that will become the base of the etching mask, exposing and developing the pattern of the rod and the etching mask are carried out in a gas atmosphere or in a vacuum. Since the process can be carried out using a liquid, the pattern processing efficiency can be improved compared to conventional methods using a liquid. Furthermore, by shortening the process and reducing the number of equipment, a large amount of lean room can be saved. Therefore, it is possible to fully cope with future submicronization of integrated circuits. In addition, since an etching mask with excellent etching resistance can be formed, there are advantages such as selective etching of the material to be processed using the etching mask.

FIG. 11 is a schematic configuration diagram showing an apparatus used in the second embodiment method of the present invention. Note that the same parts as in FIG. 9 are given the same reference numerals, and the detailed description of U1 is omitted. In this apparatus, the series of steps of thin film formation, patterning, and selective etching are performed in separate containers.

That is, a vacuum container 11a for forming a thin film by photochemical reaction, and a vacuum container 11b for etching the thin film.
and a vacuum chamber 11C for selectively etching the lower 1111m etching material using the thin film pattern as a mask are sequentially connected to each other via gate valves. The light tA17 is arranged above the container 11a, and the sample 12 is vertically irradiated with this light 8!17.

Above the container 11b is a light source 20. An optical reduction transfer device 49 consisting of a mask substrate 47 and a reduction lens system is arranged. Then, the sample substrate 12 is attached to this device 49.
The pattern of the mask substrate 47 is transferred onto the mask substrate 47 in a reduced size.

In addition, in the figure, 13a, 13b, 13c are holders, 16a
, 16b, 16C are gas exhaust ports, 33a.

33b, 33c, and 33d are gate valves, and 50 is a gas inlet.

When this device is used, first, as in the previous embodiment, the container 1 is
．． An organic thin film [143] is deposited on the sample substrate 12, that is, on the 8102 film 42 in 1a. Next, after evacuating the inside of the container 11a, the gate valve 33b is opened and the substrate 12 is removed.
is placed on the holder 13b of the container 11b. here,
Transfer the J: remask pattern to the reduction transfer device 49.

That is, the organic HII 43 is etched according to the mask pattern to form an etching mask. Next, the gate valve 33C is opened and the substrate 12 is placed on the holder 13C inside the container 11c. Here, the 5102 film 42 is selectively etched using the etching mask formed above in the same manner as in normal plasma etching.

That is, a reactive gas such as CI 2 or CF4 is introduced into the container 11c, and high frequency power is applied between the holder 13c and the container 11C (earth wall of the container) in the same manner as in the parallel plate plasma etching magazine. Selective etching of S i 02 is performed. As a result, 5IO as the material to be processed
It is possible to finely process the two-piece 42 into a desired shape.

Note that during etching in the container 11c, it is better to cool the sample substrate 12.

17- Thus, according to the method of this embodiment, as in the method of the previous embodiment, j(f product,
A series of steps such as patterning of the thin film and selective etching of the processed material can be performed in a vacuum or in a gas atmosphere, and therefore the same effects as in the previous embodiment can be obtained. Also, by using separate vacuum containers 11a, 11b, Ilc? ! Number test $311 board 12 in container 11a
-) Container 11b → Container tie are moved one by one 14
Each container can be processed independently, thereby improving productivity.

FIG. 12 is a schematic configuration diagram showing an apparatus used in the third embodiment method of the present invention. This apparatus differs from the apparatus shown in FIG. 9 in that the thin film is etched using an electron beam. That is, the container 11 is used instead of the light source 20.
An electron optical lens barrel 55 consisting of an electron gun 51, various types (nonsense system 52, aperture mask 53, pot inner system 54, etc.) is provided above.
The electron beam 1 from 1 is scanned on the sample substrate 12 = 18-.

It goes without saying that even if this device is used, the same effects as in the first embodiment can be obtained.

Note that the present invention is not limited to the embodiments described above. For example, as the light irradiated to the mixed gas for forming the thin film, in addition to the wavelength that dissociates the reactive gas, light with a wavelength that excites the raw material gas may be used in combination.

Furthermore, the energy beam for exposing and developing III is not limited to light or electron beams, but ion beams may also be used. In addition, the raw gas is not equally limited to Te1-ramethylsilane,
It is possible to use various compounds such as metals or semiconductors and carbon and hydrogen. For example, 81(CH13)a
, Qe (Ct(3)4 , Cd (CI-13
)2.

Zn (C1-13)2, Sn (CI-13)4
, B l (CH3)3 , Ga (C113>
It is also possible to use 3 or Al2(CI9)s. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

Figures 1 to 8 are for explaining the experimental results that are the basis of the present invention, and Figure 1 is a cross-sectional view showing the state in which WI-based cells are formed by a photochemical reaction, and Figures 2 and 3 are
The figure is a characteristic diagram showing the relationship between the deposition rate and the proportion of j8 element in the mixed gas, Figure 4 is a characteristic diagram showing the relationship between the deposition rate and the mixed gas pressure, and Figure 5 is a characteristic diagram showing the relationship between the deposition rate and the mixed gas pressure. Figure 6 is a characteristic diagram showing the relationship between wafer temperature and deposition rate; Figure 7 is a characteristic diagram showing the relationship between deposition rate and the proportion of chlorine in the mixed gas; 8
Figure 9 is a dimensional characteristic diagram showing the relationship between deposition rate and mixed gas pressure, Figure 9 is a schematic configuration diagram showing the equipment used in the method of the first embodiment of the present invention, and Figure 10 is a microscopic diagram using the above equipment. FIG. 11 is a cross-sectional view showing the pattern forming process, FIG. 11 is a schematic diagram showing the device used in the method of the second embodiment, and FIG. 12 is a schematic diagram showing the device used in the method of the third embodiment. 1... Wafer, 2... Light, 3... Organic thin film (deposited film), 11.11a, Ilb, IIG... Vacuum container,
12... Sample substrate, 13.13a, 13b, 13c
m'yIha holder, 14...drive mechanism, 15.50
...Gas 1 person D, 16.16a, 16b, 16cm"
jjsu IJ [Air port, 17...Light source for film formation, 18.
...Light for thin film formation, 19.22...Light passing window, 2o.
...Light source for thin film etching, 21...III! Etching light, 31°32 ・= Kasl l ilJ I
II! , 33.33a, 33b. 33c, 33d... Gate valve, 49... Optical reduction transfer device, 55... Electron optical lens barrel. Applicant's representative Patent attorney Takehiko Suzue 21- Figure 1-

Claims (11)

[Claims] (1) A sample substrate is exposed to a mixed gas of a raw material gas containing raw materials for the thin film to be deposited on the substrate and a reactive gas containing at least a halogen element, and the mixed gas is irradiated with light to cause a photochemical reaction. A thin film is deposited on the substrate, then the substrate is exposed in a high vacuum, and then the I! A fine pattern forming method characterized by selectively irradiating a thin film on a root with a predetermined energy beam. (2) The product of I and II is performed in the reaction vessel into which the mixed gas and light are introduced, and then the energy beam is irradiated after the vessel is evacuated. A method for forming a fine pattern according to claim 1. (3) The above wIm is multiplied by 1 in a reaction vessel into which the mixed gas and light are introduced, and then the substrate on which the thin film is laminated is placed in another vessel evacuated to high vacuum, and then the above energy is applied. The method for forming a fine pattern according to claim 1, characterized in that beam irradiation is performed. (4) The means for selectively irradiating the energy beam scans the substrate with a focused energy beam to draw a desired pattern on the thin film on the substrate. The fine pattern forming method according to scope 1. (5) The means for selectively irradiating the energy beam is configured to irradiate the energy beam onto the W plate through the mask substrate, and transfer the pattern on the mask U plate to the thin film on the substrate. A method for forming a fine pattern according to claim 1, characterized in that: (6) The energy beam may be light, electrons or -
2. The fine pattern forming method according to claim 1, wherein an ion beam is used. (7) The method for forming a fine pattern according to claim 1, wherein a compound of a metal or a semiconductor, carbon, and hydrogen is used as the raw material gas. (8) The source gas is S I (CHa) 4
. S i (Chll)6, Ge (CH3)4
, Cd (CH3)2, Zn (CI43)2
, 8n (CH3)4. B i (CH3) 3 , Ga (CI-1:l
) 3 or Al1(Of-h)6. (9) The method for forming a fine pattern according to claim 1, wherein light having a wavelength that dissociates the reactive gas is used as the light irradiated to the mixed gas. (10) As the light irradiated to the mixed gas, light with a wavelength that dissociates the reactive gas and light with a wavelength that excites the raw material gas are used. A method for forming fine patterns. (11) adding mercury as a sensitizer to the raw material gas,
At the same time, in addition to the light that dissociates the reactive gas, the light that excites the mercury is used in combination!
! F. A method for forming a fine pattern according to claim 9 or 10.