JPH02114525A - Removal of organic compound film and its removing device - Google Patents

Abstract

PURPOSE:To remove an organic compound film with high speed and surely without generating damage to a sample by supplying radicals such as halogen elements and gas containing water vapor to a substance to be treated having an organic compound film. CONSTITUTION:Active seeds 44 of gas containing halogen elements such as fluorine and gas 45 containing water vapor are made to gush out from the respective gas supply openings 41a and 42a provided in a plurality. Further, a sample plate 46 carrying wafers 43 is connected to a motor moves relatively in parallel with a plurality of gas supply openings 41a and 42a for uniformly irradiating gas all over the wafers 43. Here, a distance between a nozzle and a substance to be treated is held in a range under 35mm. Thereby, concentration of the active seeds of fluorine and addition gas such as hydrogen gas is locally heightened so as to make high-speed etching possible and enable removal of the organic compound film to be performed with high speed giving no damage to a substrate to be treated.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for removing an organic compound film such as a surface treatment or a photoresist in a semiconductor device manufacturing process or other fields, and a method for removing an organic compound film such as a photoresist. related to the equipment used.

(Prior art) Organic compounds such as photosensitive photoresists are used in microfabrication technology in the manufacturing process of semiconductor devices, etc., or in processing technology in other fields (e.g., printed circuit board processing, compact disk, laser disk processing processes), etc. Photoetching process using organic resist film (P
Hot.

EtchlngProcess; PEP)
(described below) is an important and essential process. Using this as a mask, this organic resist is removed after the underlying treatment (etching, ion implantation, etc.) is completed. The removal method is to remove it in a solution represented by a mixed solution of H2SO and H2O□, or a solution in which H2O is added, or to remove it in a solution such as a mixed solution of H2SO, H2O
02) A method of dry ashing during gas discharge is currently mainly used.

However, in the former process using a solution, there are problems such as the safety of solution management work.

In particular, it is unsuitable for semiconductor device manufacturing processes, etc., which do not require processes using liquids. In addition, when an organic compound film photoresist is used for patterning aluminum (AΩ) metal, etc., which is an electrode material used in the semiconductor device manufacturing process, in a mixed solution of H2SO4 and H2O□,
There is a problem in that the metal is corroded and its uses are limited.

As a way to solve this problem, the latter oxygen (o
2) There is a dry ashing (ashing) method in which an organic compound film is removed using plasma. In this method, a sample on which an organic compound film is formed is placed in a barrel-type or parallel plate-type reaction vessel that generates an electric discharge, and oxygen (02) gas is discharged, and the organic compound film is formed as a sublayer. It is.

According to this method, compared to the method using a solution described above, it is simpler and the base material may be metal or the like, and there is no need to limit the base material.

However, this dry ashing method results in damage or resist residue on the surface of the sample because the sample is placed during the electrical discharge necessary to obtain a practical predetermined removal rate.

A specific example of a photoetching process using plasma will be described with reference to the schematic diagram of FIG. FIG. 12 is a cross-sectional perspective view showing a step of forming a gate electrode of an MO3 type device on a substrate such as silicon.

First, as shown in FIG. 12(a), a phosphorous-doped polycrystalline silicon film 122, which will become a gate electrode, is formed on a semiconductor substrate 12O on which a gate oxide film 121 is formed, and then a resist film, which is an organic compound film, is formed. A film 123 is applied over the entire surface.

Thereafter, as shown in FIG. 12(b), pattern exposure is performed and development is performed so that a resist layer 123a remains on a desired portion of the polycrystalline silicon film 122.

Next, as shown in FIG. 12(C), the resist layer 1 is
23a as a mask, reactive ion etching (RI)
E) The rest of the polycrystalline silicon film 122 is removed, leaving the gate electrode 122a, using a method such as E). Thereafter, the resist layer 123a is removed using the oxygen plasma described above, but at this time, as shown in FIG. 12(d), the gate voltage t
! ! A residue 124 remains on the surface of 11122a or the gate oxide film +21. Further, due to the incidence of charged particles in the plasma, irradiation damage is induced in the gate oxide film 121 or its underlying layer.

Even if an MO3 type device is formed through such a process,
There are problems in that the residue may have an adverse effect on subsequent processes, and the characteristics of the semiconductor element may be adversely affected, such as a decrease in the dielectric strength of the oxide film. This problem of residue or damage to the sample surface occurs when both barrel-type and parallel plate-type ashing devices are used; in the latter case, the incidence of charged particles on the sample surface during discharge is high. , the occurrence of damage is more noticeable than the former. In addition, in the photoetching process using oxygen plasma dry ashing, as mentioned in the explanation of Fig. 12, the sample is exposed to electric discharge as in the case of etching and soching using the reactive ion etching (R summer E) method. When removing an organic resist that has been used as a mask for ion implantation and has been exposed to ion bombardment, there is a problem that it is more difficult to remove and more likely to leave residue than when these process steps are not performed.

In this way, in order to completely remove the residue of the organic compound film so that it does not cause problems in later processes, oxygen (0□) ashing must be performed for a long time of about 1 hour or more. When ashing is performed for a long time, a problem arises in that damage to the sample increases. Further, the fact that the treatment for removing the organic compound film takes time is disadvantageous in terms of the manufacturing process. Therefore, in order to remove the sample with an organic compound film at high speed, the temperature of the sample is lowered to 1.
Although a method of raising the temperature to 00° C. or higher is also used, there is a problem that this increases the size or complexity of the processing equipment.

On the other hand, in microfabrication using reactive ion etching,
Etching products sputtered from the surface of the substrate are attached to the side walls of the resist, which is a pattern or etching mask, to form a thin film. FIG. 13(a) is a diagram schematically showing this situation. A silicon oxide film 131 is formed on a silicon substrate 130 by thermal oxidation, an aluminum film 132 is deposited thereon by sputtering, and etching is schematically shown using a resist H3 as a mask. Ions 135 are incident perpendicularly to the substrate 130 and bombard the surface to be etched. At this time, the etching product 136 having a low vapor pressure is sputtered by the ions and flies away, but a part of it re-attaches to the side wall, forming the side wall protective film 134. This sidewall protective film H4 is important in preventing radicals from attacking the thin film to be etched and in forming a vertical pattern. However, even after the etching is finished and the resist is ashed, it is not easily removed, and as shown in Figure 13(b), it remains on both sides of the pattern like ears, causing dust. there were.

The above-mentioned sidewall protective film is formed no matter what the object to be etched is. When the object to be etched is polycrystalline Si, a thin film of Si is formed, and when the object to be etched is Al, a thin film of AI is formed. Although it is possible to remove such a sidewall protective film using a hydrofluoric acid-based chemical, in the case of polycrystalline St, the underlying gate oxide film is etched at the same time. on the other hand,
In the case of AI, when it is immersed in hydrofluoric acid, the Ag and the underlying silicon oxide film, which is an insulating material, are also etched. Therefore, there is a need for a dry etching technique for such a sidewall protective film.

(Problems to be Solved by the Invention) As described above, in the conventional method of using a solution to remove an organic compound film, it is difficult to manage the solution, it is difficult to ensure safety, and the underlying materials are limited. There is. The method using dry 0□ ashes causes damage to the sample, and if the sample has undergone a certain process, a residue is formed that is difficult to remove, and in that case, there are problems such as a long processing time. Further, when removing the sidewall protective film after etching, there is a problem in that the patterned film or underlying material is etched away.

The purpose of the present invention is to solve the drawbacks of the conventional organic compound film removal methods described above, and to remove organic compound films quickly and reliably without causing damage to the sample. An object of the present invention is to provide a method and a removal device.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides radicals such as the halogen element generated by exciting a gas containing a halogen element such as fluorine,
The present invention provides a method for removing an organic compound film, characterized in that a gas containing water vapor is supplied to an object to be treated on which an organic compound film is formed, and an apparatus applied thereto.

That is, the present invention provides a reaction vessel containing a treatment target having an organic compound film formed on the surface thereof, and a first
In the method for removing an organic compound film such as a resist used as a mask for selective etching, the first and second gases are introduced. The gases are introduced from separate gas inlet ports, one of the gas inlet ports is installed at a distance of 35+ am or less from the surface of the object to be treated, and the other is installed at the same distance or a distance further than this, and the This method optimizes the amount of active species of halogen elements that reach the surface of the object to be processed.

Further, the present invention provides a method in which a first gas containing a halogen element and a water vapor are placed in a reaction vessel containing a substrate to be processed which has been selectively etched using an organic compound film as a mask and has a sidewall protection film remaining on the etched sidewall. In the method for removing the sidewall protective film together with the organic compound film by introducing a second gas containing one of them is installed at a distance of 351 or less from the surface of the object to be treated, and the other is installed at the same distance or a distance farther than this,
This method optimizes the amount of active species of halogen elements that reach the surface of the object to be processed.

The present invention also provides an organic compound film removal apparatus for carrying out the above method, which includes a reaction vessel for housing a workpiece having an organic compound film formed on its surface, and a first reactor containing a halogen element in the reaction vessel. means for supplying a second gas containing water vapor into the reaction vessel;
an organic compound film removal apparatus comprising means for evacuating the inside of the reaction container, wherein separate introduction ports are provided for introducing the first and second gases into the reaction container, and one gas is introduced into the reaction container; The gas inlet is installed at a distance of 35 Ill or less from the surface of the object to be treated, and the other gas inlet is installed at the same distance or farther than this.

(Function) Radicals such as the halogen element generated by exciting a gas containing a halogen element such as fluorine have strong reactivity, and even if they are alone, they react with the organic compound film of the object to be treated and remove the organic compound film. be able to. However, in semiconductor processes, etc., the underlying material is, for example, silicon (
Si) or silicon oxide (S i O2), if only fluorine halogen radicals are supplied, the underlying S
Since t and 5i02 are etched, it cannot be used as a process.

In addition, the removal rate of the organic compound film is 1000 people/1n.
It's below average and not very fast. Therefore, when a halogen element such as fluorine and a gas containing water vapor are simultaneously supplied as in the present invention, the etching rate of Si and SiO The etching rate of the compound film is extremely fast, exceeding 5000 people/sin. this is,
Hydrogen (H) radicals and OH radicals are generated by reacting with radicals of halogen elements such as fluorine.

Alternatively, this is because HF radicals and the like react with the organic compound film and the container, but hardly react with other inorganic materials such as Si and SiO2. Therefore, it is possible to remove an organic compound film having an extremely high etching selectivity with respect to the underlying inorganic material such as Si or 5in2.

However, in such a system where active species coexist, the life of the active species is short, and it is important to set the gas mixing method, gas pressure, and distance between the gas inlet (gas mixing port) and the object to be processed. In particular, the distance between the object to be treated and the gas inlet must be set appropriately. In addition, when supplying the active species generated by electric discharge, the pressure inside the container is about 0.1 to 1 OTorr.

Next, the operation of the method for removing an organic compound film according to the present invention will be explained in detail with reference to the drawings.

FIG. 1(a) is a characteristic diagram showing the respective etching rates of photoresist and n+ polycrystalline silicon of the organic compound film on the processing object when the amount of H2O supplied to the processing object is changed. be.

Here, NF, F (fluorine) radicals generated from gas discharge, and water vapor (H2O) were supplied to the object to be processed. The gas flow rate of NF and gas into the reaction vessel is 3.
0 sccra and the total pressure is 0.2 Torr.

As can be seen from this characteristic diagram, while the etching rate of polycrystalline silicon decreases with the addition of H2O, the etching rate of photoresist sharply increases. When the amount of H2O added is 2Osec or more, n+
Since the etching rate of polycrystalline silicon is 0 [in/mIn], ideal resist stripping characteristics can be obtained. In this way, the removal rate of the organic compound film due to the introduction of H2O etc. and the action of active species containing halogen elements is related to the amount of H2O added, and as shown in Figure 1, the removal rate of the organic compound film is related to the amount of H2O added, as shown in Figure 1. It is sufficient to select an amount that provides a selectivity ratio of .

Here, a system using a reaction between F radicals and H2O will be described. Gas containing F, such as NFi, CF4,
By mixing F radicals generated by discharging a gas such as CF4+O□ and H2O in a reaction vessel, a large amount of O is produced by the reaction 2F+H2O→2HF+0. The above reaction is extremely slow. Therefore, at a location far from the gas mixing position, most of the F is consumed by the above reaction, but at a location close to the gas mixing location, there is a region where F radicals and O are appropriately mixed. In such a region, it is thought that a small amount of F first reacts with the organic matter to weaken the organic matter, and then O reacts with the weakened organic matter, thereby making it possible to efficiently remove the organic matter. Further, intermediate products such as OH radicals generated in the process of the above reaction also react with organic substances, and are thought to play a role in weakening the organic substances.

As described above, active Fi (for example, 0.H, etc.) that reacts with and removes organic matter and active species (for example, F, OH, etc.) that react with organic matter and weaken it.

In a system in which H, etc.) coexist, organic substances can be removed efficiently and at high speed. In addition, the amount of H2O added is 30s
On the contrary, the resist etching rate decreases above ce■ (Resist removal is achieved by increasing the amount of H and O added with 2OSe
It turns out that around el is good. When H and O are low,
It is thought that if the amount of 0 produced is small and the amount of H2O is large, the amount of F will be too small and the removal rate will be slow. In addition, in this case, F supplied approximately evenly into the reaction vessel
H2 from a place 10mm away from the object to be treated to radicals
Ml was determined by supplying O.

FIG. 1(b) shows the results of determining ΔFJ of the photoresist etching rate distribution within the surface of the object to be processed when the distance Md from the gas inlet to the surface of the object to be processed is varied. Measurements were made while varying the pressure inside the container. As the gas inlet, an outlet of a double quartz tube as shown in FIG. 1(C) was used, and F radicals were supplied from the inside of the double tube and H2O was supplied from the outside. The pressure shown in FIG. 1(b) is 0. As is clear from the characteristics of 15 Torr, the etching speed of the resist is extremely slow when the distance is less than 5 mm.
(below 4000 Å), and it is slow even at 35 av or more. That is, it can be seen that etching can be performed over a wide range and at high speed in the range of 5 to 35+gm.

Note that this characteristic also changes depending on the gas pressure. The pressure of the gas greatly affects the lifespan of active species, but in the method of generating active species by electric discharge, the pressure is 0.1 to 1 O.
It is best to use a region of about Torr, 0.1 to I T
In the region of orr, a distance of 5 to 35 mm is appropriate, and the pressure is greater than this (~10To
rr), the upper limit of distance is small (e.g. 2Oma)
+) is preferable, and conversely, the lower limit may be a finite distance of 5111 or less. Here, the setting of the upper limit of the distance is
If the distance #d between the gas inlet and the surface of the object to be treated is too long, F
This is because the radicals are consumed by the above-mentioned reaction and almost disappear on the surface of the object to be treated. Furthermore, if the distance fid is too short, a large amount of F radicals will be supplied to the surface of the object to be processed, and F-based deposits will be generated, contrary to etching.

Further, if the base is aluminum, there is no problem because it is not etched by active species of halogen elements such as fluorine. In addition, radicals of halogen elements such as fluorine have an extremely long life, and those generated in a place other than the container containing the object to be processed can be easily transported into the container containing the object to be processed. The gas containing water vapor does not need to be excited, and can be introduced in the form of raw gas into the container containing the object to be processed. Therefore, it is possible to adopt a configuration in which the object to be processed is separated from the region where the gas is excited, and no damage is caused to the sample (object to be processed) during the process, unlike in oxygen plasma ashing or the like. Furthermore, because the radicals of halogen elements such as fluorine have a long life, even when the object to be processed is a large-diameter wafer or multiple wafers, the uniformity of organic film removal within a wafer and between wafers is improved. For example, the gas can be supplied using a plurality of blowing nozzles. Furthermore,
Since the removal speed of the organic compound film can be extremely fast, it can be applied to small equipment such as a single-wafer cutter that processes wafers one by one in semiconductor processes, etc. It has the advantage that it can be used in devices with a structure that is easy to handle.

In addition, when radicals of halogen elements such as fluorine and gases containing water vapor coexist, the removal rate of the organic compound film becomes extremely fast. It is also possible to locally remove the organic film on the object by spouting it out. Furthermore, the method for removing an organic compound film according to the present invention is not only useful for removing photoresist films that are used to etch electrode materials such as aluminum or polycrystalline silicon in semiconductor processes, but also for removing residues that may be generated in normal 02 ashing. It is also possible to perform etching at a higher speed and without leaving a residue even when processing an object on which an organic film is formed, for example, which requires processing for more than one hour to eliminate the residue. It goes without saying that the removal of the organic compound film is used not only for removing photoresist but also for removing dirt on the surface due to the organic film, and for example, it can be used as a dry cleaning method.

In addition, aluminum (All) by resist mask
After etching, it becomes difficult to remove the resist, and in order to perform anisotropic etching, a protective film of organic matter may be formed on the sidewall, and the removal of the sidewall protective film is also 0□
Although it is difficult to remove by ashing, it is effective according to the present invention. Furthermore, in the etching of silicon, etc., sidewall protective films such as reaction products mixed with resist materials are formed, and these films are sometimes used for shape control in vertical etching, etc., and the present invention can also be used to remove these films. is valid.

Now, considering the case where NF and H2O are introduced to remove the sidewall protective film, the F radicals generated by the discharge of NF have a long life and are transported to the etching chamber distant from the discharge tube. There, it reacts with the supplied H and O.

This reaction proceeds extremely quickly, with most of the F becoming HF and only a small amount of F radicals remaining. The F radicals remaining in this process etch the sidewall protective film. At this time, polycrystalline St is not etched, but since the sidewall protective film is an aggregate of fine particles literally several hundred thick, for example, even if a lump of metal exists stably in the air, the fine powder It is inferred that when exposed to the atmosphere, the sidewall protective film is also etched, just as it instantly burns to form an oxide.

Furthermore, in the present invention, since the organic compound film such as resist and the sidewall protective film can be removed using the same method and gas,
It becomes possible to remove both at the same time, and it is possible to simplify the process.

(Embodiment) First Embodiment FIG. 2 shows a schematic diagram of an embodiment of an apparatus for carrying out the method of the present invention. 1 is a reaction chamber; reaction chamber 1
A substrate 2 to be processed is accommodated therein. Further, a first vibe 4 is connected to the reaction chamber 1 for supplying active species containing a halogen element such as fluorine (F). The active species are supplied into the reaction chamber 1 by the vibrator 4.
A first gas containing a halogen element such as fluorine is introduced from the other end 7, and this is carried out via a discharge tube 6 connected to a microwave power source 5 and a supply vibrator. Further, the reaction chamber 1 is configured to be evacuated through an exhaust port 3.

Furthermore, a second vibrator 8 for introducing a first gas containing water vapor is connected to the reaction chamber 1, and when introducing a water vapor, a vessel 9 containing water (H2O) is connected. A carrier gas is introduced into the vibrator 10 into which the water has been introduced into the vessel 9, and the water is bubbled,
Hydrogen and water vapor are sent to the reaction chamber 1.

Note that 11 in the figure is a valve for controlling the flow rate of water vapor. Further, 12 is a sample stage for mounting the substrate 2 to be processed. When introducing a gas with a low vapor pressure such as N2O, it is particularly effective to introduce it using a carrier gas. Further, the distance d between the N2O inlet and the object to be processed is set to be a finite distance of 35111 or less.

Next, a first embodiment method according to the present invention will be described in which this apparatus is used to remove a photoresist on a semiconductor substrate as an organic compound film.

Here, NF gas is used as a gas (first gas) containing F (fluorine), which is a halogen element, hydrogen (N2) is used as a carrier gas, and a gas containing water vapor (
N2O vapor bubbled with N2 is used as the second gas).

FIG. 3 is a perspective sectional view showing the etching process of a substrate to be processed accommodated in the reaction chamber 1 of the apparatus shown in FIG. Here, the object to be processed is a semiconductor substrate 21 in the MO3IC manufacturing process as shown in FIG. 3(a).
A polycrystalline silicon film or the like formed on the gate insulating film 22 is etched by RIE using the photoresist 24, which is an organic compound film, as a mask to form the gate electrode 23.
was formed.

This substrate to be processed is housed in the reaction chamber 1 shown in FIG. 2, NF and gas are supplied from the first vibrator 4, and the discharge tube 6
The gas is excited, and the fluorine F radicals generated thereby are introduced into the chamber 1. Hydrogen gas bubbled in a vessel 9 is supplied into the reaction chamber 1 by a second vibrator 8 installed separately. Here, the flow rates of NF, gas, and hydrogen gas are each 0. It was set as constant at I Torr, but NF
, gas, and hydrogen gas can be changed as appropriate within a range that provides the required etching rate and selectivity.

When the photoresist was processed under the above conditions, the resist removal rate was as high as 7000 people/a+In, and the processing time was about 3 minutes. As a result, as shown in FIG. 3(b), no resist residue formed on the gate electrode 22 was observed, confirming that it had been completely removed. Further, as the carrier gas introduced into the chamber 1, it was found that it is effective to use hydrogen gas as in this embodiment, but in addition to hydrogen gas, Ar, N2. A carrier gas such as O□ may be used, or a gas containing only water vapor instead of water vapor and N2 may be used to remove the organic compound film without leaving any residue and at high speed. In addition, as a gas that generates active species containing halogen elements such as fluorine (F), CD E
(Cheslcal Dry Etching), for example, in addition to NF3, SF6. CF4. C2F6. C3FB.

CF4+0□, C2F6+O□* C3FB +0□
, X e F 2 *F 2 or the like, or a gas containing a halogen element other than fluorine may be used.

Second Embodiment In this embodiment, a third embodiment method according to the present invention will be described in which etching is performed while moving the wafer, in order to uniformly etch a predetermined organic compound film on a wafer.

FIG. 4(a) is a schematic diagram showing the characteristic main parts of the embodiment device applied to this embodiment, and other configurations are shown in the second embodiment.
It is substantially similar to the device shown in the figure. Each of the gas supply nozzles 41 and 42 supplies a different gas, and each gas supply port 41a, 42a is provided with a plurality of gas supply ports 41a, 42a.
active species of gas containing halogen elements such as fluorine 44
A gas 45 containing water vapor is ejected. Here, the nozzles 41 and 42 separately extend in a direction perpendicular to the plane of the paper, and a plurality of gas supply ports are arranged along that direction. In this device, adjacent nozzles 4 are used to effectively mix the two types of gas.
1.42 gas supply ports 41a and 42a are set to face inward at a certain predetermined angle. Furthermore, in this apparatus, for example, the sample stage 46 on which the wafer 43 is placed is connected to a motor (not shown) and moves in parallel relative to the plurality of gas supply ports 41a and 42a, The entire surface of the wafer 43 is uniformly irradiated with the gas. Here, the distance between the nozzle and the object to be processed is maintained within a range of 35 mm or less, as in the previous embodiment.

As a result, the environment of active species of fluorine and additive gas such as hydrogen gas can be locally increased, and the gas supply ports 41a, 42a and the wafer 43 move relative to each other, so that the entire surface of the wafer 43 is covered with gas. is supplied, enabling faster etching.

In addition, as a modification of the device shown in FIG. 4(a), as shown in FIG. A nozzle 51 having a small tubular outlet is disposed close to the substrate 52 to be treated on which the organic compound film 53 is formed, and the gas is blown out to blow out the local portion 53a of the organic compound film. Etching is also possible. By moving the object to be processed 52 or the nozzle 51, it is also possible to selectively etch only a desired portion, such as linear etching.

Furthermore, a configuration for supplying gas to the tube 2 where another organic compound film is formed may be shown in the schematic diagram of FIG. 4(C). The same parts as in FIG. 2 are given the same reference numerals. Here, the active species containing the halogen element of fluorine are exposed to microwave fls # as in the apparatus shown in Fig. 2.
, 5 in the discharge section 6a, and is supplied to the sea urchin/%2 through the first vibrator 4a made of quartz. moreover,
A vibrator 56 made of quartz and having a larger opening area than the first vibrator 4a is provided to surround the outside of the vibrator 4a and to supply gas containing water vapor. That is, the vibrators 4a and 56 have a double structure, and each gas is supplied to a gas supply port 57 directed toward the wafer 2.
Supplied from. Note that the distance d between the gas supply port 57 and the wafer 2 is set within a range of 35 mm or less, as in the previous embodiment. Moreover, 55 in the figure is a microwave cavity.

Here, the cross-sectional shapes of the openings of the structural pipes 4a and 56 of the 2LIf are shown in FIGS. 5(a) and 5(b). As shown in the figure, the cross sections of the vibrators 4a and 56 are concentrically circular or point symmetrical, and the first and second gases (
This is advantageous because gas containing a halogen element and water vapor can be uniformly supplied to the object to be processed.

As in this example, the first active species containing the norogen source
If the second gas containing water vapor is supplied to the object to be processed from the inner vibrator 4a and the second gas containing water vapor from the outer vibrator 56, the gas containing the l\rogen source will adhere to the inner wall of the reaction vessel. etc., it becomes difficult to act on unnecessary areas other than the object to be processed, and conversely, it can be supplied to the desired areas of the organic compound film on the surface of the object to be processed with high selectivity, improving the efficiency of removing the organic compound film. It is advantageous to be able to encourage people to do so.

Furthermore, by appropriately selecting the flow rate and flow rate, it is of course possible to supply the gas containing water vapor to the object to be processed from the inner vibrator and the gas containing the halogen element from the outer vibrator.

In addition, as a gas supply means having a structure having a vibrator in two melons, a device in which a plurality of two or more vibrators are provided to the object to be treated is shown in detail using the schematic diagrams in FIGS. 6(a) and 6(b). Explain. Figure 6(a) is its plan view, Figure 6(b)
is a cross-sectional view taken along line A-A in FIG. In the figure, a means 60 for supplying a gas containing a halogen element and a gas containing water vapor to the object to be processed is made of quartz, and the means 60 for supplying the gas uniformly supplies the gas to the surface of the object to be processed. A plurality of double vibros 1 are provided so that the inner vibro 1a in the double vibros 1
A gas containing a halogen element is supplied from 61b, and water vapor is supplied from 61b.

Here, for example, as the gas containing the halogen element,
When this example was applied to a 5-inch wafer on which a resist, which is an organic compound film, was formed on the surface using a halogen gas such as CF that can dissociate fluorine atoms as active species, It was possible to remove the resist on the surface without leaving any residue at an etching rate of 7,000 people/10 or more. According to this embodiment, it is possible to uniformly remove the organic compound film on the surface of a large-area object such as a large-diameter wafer by etching without leaving any residue.

Third Embodiment Here, as a third embodiment of the present invention, an example of a method for introducing H2O vapor will be described.

When using H2O vapor as the second gas, the problem is how to introduce stable H2O vapor into the reaction vessel. H2O
Apply H directly from the solution reservoir etc. into the container using a vibrator using differential pressure.
Introducing O vapor causes the solution in the H2O reservoir to boil, often making it impossible to provide a stable supply of H2O vapor.

As a method for introducing stable H2O vapor, there is a bubbling method using a carrier gas. Here, other H2
The method of introducing O vapor will be described.

FIGS. 7(a) and 7(b) show schematic diagrams of the method, and the details are omitted in order to show the principle method. In the figure, 71 is a H2O reservoir, 72
is a H2O solution, 73 is a liquid introduction vibrator, 74 is a gas reservoir (buffer container), 75 is a gas outlet, 76 is a first gas introduction pipe, 77 is an H2O solid (ice), and 78 is a gas introduction pipe. . The pipe 73 in FIG. 7(a) is a capillary with an extremely small inner diameter, and one end of the capillary is H
It is in a H2O solution 72 in a 2O reservoir 71. The other end is located within the gas reservoir 74 within the reaction vessel 1. The H2O solution 72 is sucked up as a solution in the thin capillary 73 to the outlet, and is introduced into the gas reservoir 74 as vapor. The gas is then supplied into the container 1 from the gas blowing lower 5.

In the method of FIG. 7(a), the H2O solution 72 is sucked up in the capillary 73 by capillary action or by differential pressure.

The amount of H2O vapor supplied in this method is
This is done by controlling the inner diameter of the H2O reservoir 71 or the pressure in the gas phase in the H2O reservoir 71 by introducing other gases. In the method shown in FIG. 7(b), H2O is stored in the H2O reservoir 71.
solid (ice) 77 is contained. This is a method in which the vapor of ice 77 is introduced into the reaction container 1 through a vibrator 78,
The amount of H2O vapor introduced can be controlled by a valve provided on the pipe 78.

In each of the above cases, 1! of H2O solution. There is no fluctuation in the pressure in the gas phase due to a rise in the price, and H2O vapor can be stably supplied into the reaction vessel. Further, this method can be used when supplying a gas other than H2O using a solution as a source at room temperature.

Fourth Embodiment This embodiment is a method in which an organic compound film is etched using a reactive gas containing a halogen element, and then the residue is removed by washing with water.

Resist ashing methods using F/H2O and 02+CF4 systems can also leave very persistent residues on the surface. For example, in an ashing method that includes F, the resist is weakened by F, and the residue is also weakened more than when 02 ashing is performed. Therefore, the residue remaining after ashing can be removed by subsequent washing with water for several minutes.

FIG. 8 is a process sectional view for explaining the method of this embodiment. FIG. 8(a) shows a state in which an alloy film (AII-Si-Cu) 82 on a substrate 81 has been selectively etched by RIE using a resist 83 as a mask.

For this sample, 0□; 101005e, C
F4; t.

The resist is removed using a downflow type ashing device of SCC■. At this time, resist residue 84 remains on the surface of the metal film 82, as shown in FIG. 8(b). When this is washed with water, a residue 8 is formed as shown in Figure 8(c).
4 is completely removed, and furthermore, the metal film 82 is not damaged.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described. This example is a method of removing the sidewall protective film at the same time as removing the organic compound film.

FIG. 9 is a schematic diagram of the apparatus used in this example, and the second
The same parts as those in the figure are given the same reference numerals. A sample stage 12 is installed in the vacuum container 1, and the tool 2 which has been subjected to reactive ion etching is placed on this stage. An oil rotary pump 92 is connected to this vacuum container 1 as an exhaust device. A discharge tube 4 made of quartz is connected to one side of the reaction vessel 1, and a microwave of 2.45 GIIz is applied to the discharge tube 4 from a power source 5 through a waveguide 6.

NF, which is a reactive gas, is supplied to the discharge tube 6. The F radicals generated by the microwave discharge are transferred to the vacuum container 1.
and reacts with H,0 directly introduced into the vacuum vessel 1. Note that the distance between the H2O inlet 91 and the wafer 2 is set to 35 av or less.

FIG. 10(a) is a diagram showing a cross section of the sample used in this example. Thickness 10 on silicon substrate 100
A silicon oxide film 101 is formed, a polycrystalline silicon film IQ2 is deposited thereon, and the polycrystalline silicon film 102 is etched by reactive ion etching using the resist 103 as a mask. A sidewall protective film 104 remains on the etched sidewall. This sample was placed in the container of the apparatus shown in Figure 9, and after being evacuated, N F
] and H2O are introduced, microwaves are applied to discharge,
Process. When a normal cylindrical oxygen plasma ashing device is used, sidewall thin films 104 remain at both ends of the pattern as shown in FIG. 10(b), but when the present invention is used, as shown in FIG. As shown in (e), the sidewall protective film +04 could be completely removed.

The partial pressure of H2O is set to 0. When setting I Torr and changing the NF3 flow rate, the sidewall thin film will not be removed if the NF flow rate is low (10seca+ or less), but the sidewall protective film will be removed if the flow rate is sufficiently high (10scca+ or more). . According to experiments conducted by the present inventors, both H2O and NF3 are 0. It has been confirmed that the resist can be quickly removed near I Torr (approximately ±5026) without removing much of the underlying polycrystalline silicon. In the present invention, it is important that the F radicals generated by the microwave discharge react with H2O to generate a large amount of 0 radicals, and that the F radicals also act. Therefore, a gas that generates F radicals by discharge, for example, S F
b, CF4BF3, PFs, PF,
A similar effect can be obtained by using . Also,
Even if an alcohol such as CH, OH or C, H6OH is used instead of H2O, a similar effect of ashing the resist and removing the sidewall protective film can be obtained.

In FIG. 11, a silicon substrate 110 is thermally oxidized at 1000° C. to form an oxide film Ill with a thickness of 1 μm, a contact hole pattern is formed on it using a resist 112, and then a reaction using CF4 and H2 is performed. 3 shows a cross section of a sample whose oxide film LIT has been etched by ion etching.

This substrate 110 is cut in half, the resist is removed from one half using a normal oxygen plasma ashing device, and the remaining half is cut into two halves.
It was placed in the reactor shown in the figure and treated with N F J and H2O. After that, when each sample was observed using SEM, it was found that in the sample subjected to oxygen plasma ashing, a protective film remained on the side wall, similar to the example shown in Figure 10 (b). In the samples treated by the method of the present invention, no protective film was observed, and it was confirmed that the protective film was completely removed.

Note that this embodiment is not limited to polycrystalline silicon or silicon oxide films, but silicon nitride films.

Any sidewall protective film made of a material that can be etched with fluorine atoms, such as molybdenum, tungsten, and silicides of these metals, is applicable. Further, the method of the present invention and the apparatus applied thereto are not limited to the above-described embodiments, and can be implemented with various modifications without departing from the gist of the present invention.

[Effects of the Invention] As described in detail above, according to the present invention, an organic compound film can be removed without damaging the substrate to be processed and at a high processing speed. Furthermore, the sidewall protective film can be removed at the same time as the organic compound film, which is very useful.

[Brief explanation of the drawing]

FIG. 1 is for explaining the operation of the method of the present invention.
(a) is a characteristic diagram showing the change in etching rate with respect to the amount of H2O added, (b) is a characteristic diagram showing the change in etching rate with respect to distance d, and (C) is a schematic diagram showing the positional relationship between the gas inlet and the object to be processed. 2 is a schematic configuration diagram showing the apparatus used in the method of the first embodiment of the present invention, FIG. 3 is a process diagram for explaining the effects of the method of the first embodiment, and FIGS. Figure 6 is a schematic configuration diagram showing the equipment used in the method of the second embodiment, Figure 7 is a schematic diagram showing the equipment used in the method of the third embodiment, and Figure 8 explains the method of the fourth embodiment. 9 is a schematic configuration diagram showing the apparatus used in the method of the fifth embodiment, and FIGS. 10 and 11 are sectional views for explaining the effects of the method of the fifth embodiment. , FIG. 12 and 1
FIG. 3 is a diagram for explaining a conventional example. 1...Reaction container, 2,43.52...Object to be processed, 3
...Exhaust port, 4...First pipe, 8...Second vibe, 9...Vessel, 12.46...Sample stand,
21... Semiconductor substrate, 22... Gate oxide film, 23
...Gate electrode, 24...Resist, 41.42.
...Nozzle, 71...H2Oa, 73...Capillary 74...Gas reservoir, 75...Gas outlet. Applicant's agent Patent attorney Takehiko Suzue H2Q 3tt
'-V (SCCm) (a) Figure 1!1 Distance d (mm) (b) <C> Figure 1 57" 3 iTJ (a) (b) Figure 5 (a) (b) Figure 6 8 factors L----1++J (a) (b) Figure 7 Figure 10 Prisoner Figure 12 (a) (b Figure 13

Claims (1)

[Scope of Claims] (1) A first gas containing a halogen element is placed in a reaction container that houses an object to be treated having an organic compound film formed on its surface;
A method for removing an organic compound film by introducing a second gas containing water vapor, the method comprising:
The gases are introduced from separate gas inlet ports, one of the gas inlet ports is installed at a distance of 35 mm or less from the surface of the object to be treated, and the other is installed at the same distance or a distance further than this, A method for removing an organic compound film, characterized in that the amount of active species of a halogen element that reaches the surface of the object to be processed is optimized. (2) A first gas containing a halogen element and a second gas containing a water vapor are placed in a reaction vessel containing a substrate to be processed that has been selectively etched using an organic compound film as a mask and a sidewall protective film remains on the etched sidewall. A method for removing the side wall protective film together with the organic compound film by introducing a second gas into the gas inlet. One is installed at a distance of 35 mm or less from the surface of the object to be processed, and the other is installed at the same distance or a distance further than this, and the amount of active species of the halogen element that reaches the surface of the object to be processed is controlled. A method for removing an organic compound film characterized by being optimized. (3) The method for removing an organic compound film according to claim 1 or 2, wherein the first gas is excited in a region different from the reaction container and then supplied into the reaction container. (4) The first gas is a fluorine atom, and its source gas is a fluorocarbon gas such as SF_6, NF_3, CF_4, or a mixed gas of these with oxygen added, or BF_3, PF_3, PF_5, XeF_2. , F_2
3. The method for removing an organic compound film according to claim 1, wherein the gas is any one of the gas group consisting of: (5) When introducing the second gas into the reaction container,
(6) A method for removing an organic compound film according to claim 1 or 2, characterized in that a carrier gas is added. Removal of an organic compound film comprising means for supplying a first gas containing a halogen element, means for supplying a second gas containing water vapor into the reaction vessel, and means for exhausting the inside of the reaction vessel. An apparatus, wherein separate introduction ports are provided for introducing the first and second gases into the reaction vessel, and one gas introduction port is installed at a distance of 35 mm or less from the surface of the object to be processed. An apparatus for removing an organic compound film, characterized in that the other gas inlet is installed at the same distance or at a farther distance than this. (7) means for exciting a first gas containing a halogen element by electric discharge, light, electron beam, heat, etc. in a region different from the reaction container, and supplying the excited active species into the reaction container; 7. The organic compound film removal apparatus according to claim 6, further comprising: (8) The means for supplying the second gas is arranged such that Ar, He,
7. The organic compound film removal apparatus according to claim 6, further comprising means for supplying a carrier gas such as the like, and means for supplying an atmospheric gas in the vessel into the reaction vessel. (9) A claim characterized in that at least one of the means for supplying the first gas and the means for supplying the second gas is provided with means for moving it relative to the object to be processed. 6. The organic compound film removal device according to 6. (10) One of the first gas supply means and the second gas supply means supplies gas to the entire inside of the reaction vessel, and the other gas supply means supplies the gas to the entire interior of the reaction vessel. 7. The organic compound film removal apparatus according to claim 6, further comprising a nozzle for injecting gas to a predetermined region of the object to be processed. (11) The means for supplying the first and second gases includes a first pipe and a second pipe having an opening diameter larger than the diameter of the opening part of the first pipe for supplying the gas. 7. The method for removing an organic compound film according to claim 6, wherein the method is a double tube consisting of a double tube, and different types of gases are supplied from the first tube and the second tube of the double tube, respectively. Device. (12) The openings of the first and second tubes are circular or point symmetrical on concentric circles, and the openings of the first and second tubes are circular or point symmetrical, and
6. The second gas is supplied to the object to be processed, and the second gas is supplied from the second pipe to the object to be processed.
The organic compound film removal device described above. (13) The means for supplying the second gas into the reaction container is H_2O from the H_2O solution to the buffer container through a thin pipe.
Claim 6, characterized in that the H_2O gas is introduced into a gaseous state and ejected from the outlet of the thin tube into a low-pressure buffer container, and the H_2O gas that has become a gas due to the ejection is supplied into the reaction container. The organic compound film removal device described above. (14) The organic compound according to claim 6, wherein the means for supplying the second gas into the reaction container is one that guides H_2O gas evaporated from solid H_2O (ice) into the reaction container. Film removal equipment.