JPH04188621A - Optical surface treatment method and device - Google Patents

Abstract

PURPOSE:To obtain firm chemical bonding on a surface modified layer, and to contrive improvement in etching-resisting property of a surface-modified film by a method wherein the film, on which a surface modification treatment will be conducted, is heated up in a surface modified layer forming process. CONSTITUTION:Pertaining to the heating method of a film 2, there are a heating method 3, in which the film 2 is heated up by heating a substrate using a heater and the like, and another heating method in which the film 2 is heated up by the irradiation of light using a laser lamp and the like, and the heating method 4 can be selectively conducted on the surface-modified region only. Also, a light is selectively made to irradiate in advance on the film 2 to be processed which is in a heated-up state in a modified gas atomosphere. As a result, a surface-modified layer 6 is formed by the photochemical reaction accelerated by heating. As a result, the surface-modified layer 6 is chemically bonded stronger than the surface-modified layer 7 which is formed by photochemical reaction only. Also, the film thickness of the surface-modified layer 6 is increased, and its etching-resisting property can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical surface treatment method for forming a pattern on a desired area of a processed surface using optical surface modification, and a processing apparatus used to carry out the method. .

[Conventional technology]

The main manufacturing process for thin film devices is mainly a process of finely processing a thin film on a substrate into a desired pattern. BACKGROUND ART In recent years, as typified by semiconductor memory devices, the capacity and performance of devices have rapidly increased, and as a result, circuit patterns have become finer and circuit structures have become more complex. On the other hand, display elements such as liquid crystal displays and plasma displays are becoming increasingly larger and their functions are becoming more complex. For this reason, the film forming process and the etching process for microfabrication mainly involve so-called dry processes, ranging from those using solutions to those using plasma or excitation gas in nitrogen or reduced pressure gas.

However, in the photolithography process generally used to perform desired microfabrication, complicated and complicated processes such as resist coating, pattern exposure, development, etching, and resist peeling are used.

In this process, solutions are used in resist coating, development, and resist stripping steps, so it cannot be a completely dry process. Furthermore, since a resist is used, this resist peels off, becomes a source of dust, and reduces yield.

Therefore, when manufacturing the above-mentioned devices using a photolithography process, the process becomes complicated and the cost not only increases, but also the yield decreases due to the generation and increase of dust, which increases the overall cost. was there.

In order to solve these problems, we have developed a process of forming a surface-modified layer with a pattern structure on the surface of the film to be processed using selective irradiation light in the modified scum, and a process of forming a protective film (etching) on the surface-modified layer. A microfabrication process method has been proposed in which a surface unmodified layer is dry-etched as a mask. According to this method, fine processing can be performed without using a photolithography process, and yield can be improved at low cost. However, the above methods may take a long time or require strong optical power for surface modification, and if the treatment is short or the optical power is weak, the protective film formed by surface modification may be chemically damaged. In some cases, the bonding strength is not strong or the film thickness is insufficient, and the resistance of the protective film is insufficient and the desired etching depth cannot be obtained.

In addition, a film is selectively deposited on the surface-modified layer or the non-modified layer by utilizing the difference in properties such as electron donating property between the surface-modified layer and the non-modified layer due to the surface modification by the selective irradiation light. In some cases, if the surface modified layer is not strongly chemically bonded or the film thickness is insufficient, the difference in properties such as electron donating properties is not sufficient, and the selectivity of subsequent deposition is not sufficient. Something happened.

[Means to solve the problem]

The inventors of the present invention have conducted extensive research in view of the problems of the prior art as described above, and have found a method that can form a protective film with sufficiently strong chemical bonding, a sufficiently thick film thickness, and strong etching resistance compared to the prior art. They discovered this and completed the present invention.

That is, the optical surface treatment method of the present invention forms a surface-modified layer in a desired area by selectively irradiating the surface to be processed with light in a desired dust atmosphere, and forms a surface-modified layer or an unmodified surface layer in a desired area. An optical surface treatment method for selectively treating a surface layer, the method comprising:
In the step of forming the surface-modified layer, the surface to be processed is heated.

The optical surface treatment apparatus of the present invention includes a reaction vessel, a gas introduction means for introducing a reaction gas into the reaction vessel, and a light introduction means for introducing processing light into the reaction vessel, and includes irradiation of the processing light. The optical surface treatment apparatus for treating the surface to be processed of a substrate placed in the reaction vessel is characterized by comprising means for selectively heating the surface to be processed.

[Effect]

According to the present invention, by heating the film to be surface-modified in the process of forming the surface-modified layer, the photochemical reaction on the surface irradiated with light is promoted, so that the surface-modified layer becomes chemically stronger. It has bonds and the film thickness becomes thicker. This improves the etching resistance of the surface-modified film, and (2) increases the difference in electron donating properties, etc., with the non-modified layer. Further, by heating the page after forming the surface-modified layer, the surface-modified layer can be made into a stable and durable region, so that pattern formation can be easily performed.

[Preferred embodiment]

The present invention will now be described in detail with reference to the accompanying drawings, which schematically show preferred embodiments. FIG. 1 is a schematic diagram showing a preferred example of the steps of the optical processing method according to the present invention.

FIG. 1(a) shows heating of a film 2 on a substrate 1 for surface modification. 3 schematically shows the heating of the film 2 by heating the substrate using a heater or the like, and 4 schematically shows the heating of the film 2 by irradiation using a laser lamp or the like, and the heating in 4 is selected only for the surface-modified region. It is also possible to do so.

A patterning process by etching will be shown below as an example of the optical processing method of the present invention. FIG. 1(b) shows the irradiation of the selective light 5 in the reformed gas onto the processed film 2 which is in the heated state previously shown in FIG. 1(a), and FIG.
), as a result of photochemical reactions promoted by heating,
This shows that the surface modified layer 6 has been formed. This surface modified layer 6 has stronger chemical bonds and is thicker than the surface modified layer 7 shown in FIG. 11(a), which is formed only by photochemical reaction without heating the processed film 2. Therefore, this surface modified layer 6
When etching the film 2 to be processed using a protective film (max), a deeper etching amount can be achieved compared to the case where the surface modified layer 7 of FIG. 11(a) is used as a protective film without heating. Obtainable.

FIG. 1(d) shows a state in which etching has been performed until the protective film 6 of FIG. 1(c) disappears. Further, FIG. 11(e) shows a state in which etching is performed until the protective film 7 of FIG. 11(a) disappears. Figure 1(d) and Figure 11(e)
As can be seen from the comparison, a deeper etching amount can be obtained by heating the film to be processed.

Next, the present invention will be explained in more detail with reference to Examples.

[Example 1] Insulating layer a-5iN, :H on quartz substrate with transparent electrode ITO
The film pattern was formed by etching.

This will be explained using FIGS. 2 and 3.

First, as shown in FIG. 2(a), the substrate 21 with ITO 21' is
An a-3iN, :H film 22 was formed to a thickness of 5,000 on the upper substrate 21 by CVD. Using this sample as a sample, this sample 31 was subsequently placed in the substrate holder 32 of the surface modification apparatus shown in FIG. 3, and the substrate was heated to 400° C. using the heater 33.

In this state, 02 gas was introduced from the gas inlet 34, and the evacuation device 30 was controlled so that the internal pressure was 1 tOrr. The mask 38 was irradiated with UV light from the low-pressure mercury lamp 36 by the illumination optical system 37, and the pattern image of the mask 38 was formed through the window 35 on the surface of the a-3iNx:H film by the projection optical system 39.

On the surface irradiated with UV light, 02 and a-3iN:H
caused a heat-promoted photochemical reaction, and a 20-thick S:O film (FIG. 2(b), FIG. 26) was formed by exposure for 20 minutes.

Using the Sho film 26 obtained in this way as a mask,
As a result of chemical dry etching using CF4+02 gas until the mask disappeared, a desired pattern was obtained as shown in FIG. 2(C). For comparison, the first example shows the case where processing was performed under the same conditions without heating the film to be processed.
1 (b) and (f). Figures 11(b) and (f)
), the pattern shown in (f) is obtained from the protective film 27 with an insufficient degree of oxidation and insufficient film thickness.
It was not possible to obtain a pattern as shown in C).

In this example, the heating temperature was set to 400° C., but it goes without saying that other temperatures can also provide a corresponding effect of promoting the photochemical reaction. As an example of this, SiO was obtained by surface modification of an a-3iN:H film under the same conditions except that the heating temperature was changed.

The dead time during chemical tri-etching (a-
3iO, time until the film disappears) is shown in FIG.

Furthermore, as another example expressing the etching resistance of the SiOx film, S l! was determined from surface pattern analysis by XPS (X-ray photoelectron spectroscopy). The chemical shift from F is shown in FIG. From the same figure, the value of chemical shift is 5iO2 (4,5e v)
It can be seen that the closer it gets to , the more oxidation progresses and the higher the etching resistance becomes.

[Example 2] An Al electrode pattern was formed on a quartz substrate by etching. This will be explained using FIGS. 6 and 7.

As shown in FIG. 6(a), an AI film 62 was formed on a quartz substrate 61 by sputtering. Sample 71
Subsequently, this sample 7J was placed in the substrate holder 72 of the surface modification apparatus shown in FIG.

Sample 71 was heated to 500° C. by lamp heating using halogen lamp 73a and reflection plate 73b.

In this state, NO2 gas is introduced from the gas introduction lower 4,
The internal pressure is 1. The evacuation device 70 was controlled so that t Or r. The illumination optical system 77 irradiated the mask 78 with oscillation light (24.8 nrn) from the KrF racer 76, and the projection optical system 79 formed a pattern image of the mask 78 on the surface of the film A1 through the window 75.

On the surface irradiated with light, NO7 and Af undergo a heat-promoted photochemical reaction, and after 10 minutes of exposure, an Aftl film with a thickness of 30 mm (Fig. 6(b), Fig. 66) is formed on the surface of the A[film]. Been formed.

Using the AIO film 66 obtained in this way as a mask,
As a result of etching using C7!2 gas until the mask disappeared, a desired pattern was obtained as shown in FIG. 6(c).

For comparison, FIGS. 11(C) and 11(g) show the case where processing was performed under the same conditions without heating the film to be processed. 1st
As shown in FIGS. 1(e) and 1(g), the pattern shown in FIG. 6(g) is obtained from the protective film 67 which is insufficient in both the degree of oxidation and the film thickness, and the desired pattern shown in FIG. 6(C) is obtained. I couldn't get a pattern.

[Example 3] After forming a conductor layer of the a-3i film ↑ on a quartz substrate with a transparent electrode ITO, an Ar pattern was formed. In this example, heating was performed selectively. This will be explained using FIG. 8, FIG. 9, and FIG. 10.

First, as shown in FIG. 8(a), I 'I' 08 ]
An a-3i film 82 was formed on a substrate 81 with a thickness of 6,000 by plasma CVD. Sample 91
Subsequently, it was placed in a substrate holder 92 of a surface modification apparatus shown in FIG. In FIG. 9, the substrate holder 92
is installed on an XY stage 93 which is controlled by a computer (not shown) and is two-dimensionally movable. Waste introduction 1-
N02 scum is introduced from 194, and the internal pressure is 10 to
The evacuation device 90 was controlled so that rr was achieved.

A 002 laser 96b for heating and a KrF excimer laser 96 for photochemical reaction are controlled by a laser control device (not shown).
a was controlled and oscillated in synchronization so that the times at which the peak power of both racers reached coincided.

The infrared light oscillated by the CO2 racer 96b is projected onto the sample 91 by the projection optical system 97b to a desired spot size (
In this example, the thickness was adjusted to 3 μm). The infrared light exiting the projection optical system is reflected by the transmissive reflection plate 98,
The sample 9] is irradiated through the window 95. Here, the transmission-reflection plate is made of a synthetic quartz plate with a thickness of 2m01, and the far-infrared reflection surface has wavelengths of 1], 7 to 12. 5 μm
The oscillation light of KrF excimer laser] 5 (24
, 8nrn) is coated with a highly reflective film that transmits light.

The oscillation light (248 nm) of the KrF excimer laser 96a, which is the light source of the second option, is transmitted by the projection optical system 97a.
Similar to the infrared light oscillated by the first light source, the desired spot size (
In this example, irradiation was performed at a wavelength of 3 μm).

The surface irradiated with light was heated by the infrared light and the temperature rose to 350° C., thereby promoting the photochemical reaction by the far infrared light.

By two-dimensionally moving the substrate holder 92 placed on the XY stage 93, a pattern of surface modified layers S i 08 (70 people) as shown at 86 in FIG. 8(1)) was formed.

This surface modified layer Sin, 86 is sufficiently oxidized and has a thickness of 70 mm, so it is a non-electronic r donor.

Subsequently, this sample 91 was placed in the substrate holder 12 of the apparatus C to 7D for selective deposition of Δ1 shown in FIG. 10 to obtain 7 samples. By the following method, A1 is applied only to the electron-donor surface.
is deposited, and no Al is deposited on the non-electron donor surface.
．． The selective deposition of M was 111 times more efficient.

First, the inside of the deposition chamber 17 was evacuated to a pressure of 1.0'torrJff by the vacuum exhaust system 10, and then the sample 11 was heated to 300° C. by the heater 13. DMAH(CH3) 2A(!H obtained through the raw material vaporizer 15 is supplied as a carrier gas from the first gas line of the gas mixer 14.
H2 is supplied from the second waste line.

DMAH and H2 are introduced into the deposition chamber 17 through the waste introduction port 16, and the total pressure inside the deposition chamber 17 is 1.5 torr.

The gas mixer 14 and evacuation system 10 were adjusted so that the partial pressure of DMAH was 1.5×10 −'torr, and deposition was performed for 10 minutes.

As a result, as shown in FIG. 8(c), no AI was deposited on the surface of the surface-modified non-electron donor S10 and the film 86. Furthermore, when the surface was analyzed using Auger electron spectroscopy, no AI was detected. On the other hand, the a-3i film surface 82, which is an electron donor, contains no carbon at all (below the detection limit) and has a resistivity of 2.7 μΩcm.
A high-quality Al film with an average wiring life of 103 to 104 hours, a hillock density of 0 to 10 cm/cm2, and no spikes was selectively deposited, and a high-quality electrode could be formed (Fig. 8 (c' ) of 88).

For comparison, the 11th example shows an example in which surface modification and A1 deposition were performed under the same conditions without heating with the 002 racer.
Shown in Figures (d) and (h). Since the surface modified film 87 in FIG. 11(d) is insufficient in both the degree of oxidation and the film thickness, it can become a non-electron donor.
As shown in the figure, AI was deposited on the entire surface, making it impossible to obtain the desired pattern.

〔Effect of the invention〕

As mentioned above, by heating the film to be surface modified in the process of forming the surface modified layer, the photochemical reaction on the surface irradiated with light is promoted, so the surface modified layer forms stronger chemical bonds. It lasts longer and has a thicker film. This improves the etching resistance of the surface-modified film. (1) It is possible to increase the difference in electron donating properties, etc. with the non-substance layer, making it easier to form a thin film pattern.

[Brief explanation of drawings]

Figure 1 (a) to Figure 1 (d), Figure 2 (a) to Figure 2
Figure (C), Figures 6 (a) to 6 (C), and Figures 8 (a) to 8 (c) are for explaining representative examples of the optical surface treatment method of the present invention, respectively. Schematic diagrams 3, 7, and 9 are schematic diagrams for explaining representative examples of the optical surface treatment apparatus of the present invention, respectively, and Figure 4 shows the relationship between substrate temperature and dead time during surface modification film formation. FIG. 5 is a schematic diagram showing the relationship between substrate temperature and chemical shift during surface-modified film formation. FIG. 10 is a schematic diagram of the CVD apparatus for A1 selective deposition.
) (f), (g), and (h) are schematic diagrams showing conventional optical surface treatment steps. 1.21.61.81... Substrate 2.21.61.81... Film to be etched (patterned) 3.4.23.63.83... Heating 5.25.65.85... Selective irradiation light used for surface modification 6.7.26.27. 66.67.86.87...Surface modified layer 88.89.
...Al film 10.30.70.90...Vacuum exhaust device 11.31.
71.91...Sample 12.32.72.92...Substrate holder 13.33
...Heaters 73a, 73b...Halogen lamp, reflector 93...
・XY stage 16.34.74.94...Gas inlet 35.75.
95...Window 36.76.96a, 96b=...Light source 37.77...
・Illumination optical system 39.79.97a, 97b...-Projection optical system 38.7
8...Mask 98...Transmission/reflection plate 14...Gas mixer 15...Source gas vaporizer 17...Deposition chamber 1 Fig.ttttt↑-3 O! Rot allowed 3ρθ 4ρθ No heating base 7 d otsusen ('C) Kireiton & (-〇)

Claims (6)

[Claims] (1) Light that forms a surface-modified layer in a desired area by selectively irradiating the surface to be processed with light in a desired gas atmosphere, and selectively processes the surface-modified layer or non-modified layer. An optical surface treatment method characterized in that the surface to be processed is heated in the step of forming the surface modified layer. (2) The optical surface treatment method according to claim 1, wherein the selective treatment etches the unmodified surface portion using the surface modification layer as a protective film (etching mask). (3) Claim 1, wherein the selective treatment comprises a step of selectively depositing a film on the surface modified portion or unmodified portion.
The optical surface treatment method described in . (4) The optical surface treatment method according to claim 1, wherein the heating is performed only on the surface-modified region by selective irradiation with light. (5) The optical surface treatment method according to claim 1, wherein the heating is selected from heating the surface to be processed using a heater, and irradiating the surface to be processed with light using a laser or a lamp. (6) A reaction vessel, a gas introduction means for introducing a reaction gas into the reaction vessel, and a light introduction means for introducing processing light into the reaction vessel, and the interior of the reaction vessel is irradiated with the processing light. What is claimed is: 1. An optical surface treatment apparatus for treating a surface to be processed of a substrate placed on a substrate, the apparatus comprising: means for selectively heating the surface to be processed;