JP3258199B2 - Semiconductor device pattern forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a fine electrode wiring of an LSI.

[0002]

2. Description of the Related Art (A) With the recent development of information processing technology,
Higher speed and higher integration LSIs have been required. For this reason, it is necessary to form a gate electrode of a transistor element constituting an LSI and a metal wiring between these elements in a fine and high density on a base having a processing step. From the viewpoint, it is important to secure the depth of focus.

On the other hand, it is clear that thinning the resist is effective, but it must be maintained as a mask during the next step of etching, so that a certain thickness (generally 1.0 μm) is required. )is necessary. For this reason, as a method of obtaining the same effect as thinning the resist while using a thick resist, for example, “Jurnalof”
Vaccum Science and Techn
logic, Vol. 9, No. 6,1991,339
A surface silylation process as disclosed in pages 9 to 3405 "has been proposed.

FIG. 2 is a cross-sectional view showing a pattern forming step of such a conventional first semiconductor device.

First, as shown in FIG. 2A, a substrate 1 is prepared, and as shown in FIG. 2B, a photoresist film 2 is formed on the substrate 1, and FIG. This is exposed to form a latent image 3 as shown. Next, as shown in FIG. 2 (d), which was immersed in an organic solvent dissolving the silylating agent, the exposure unit by silylation silylation <br/> section 4 (latent image portion 3) Form.

Next, as shown in FIG. 2 (e), reactive ion etching (O ₂ -RIE) using oxygen gas is performed to remove unexposed portions (portions other than the latent image portion 3).
Since the surface layer of the silylation portion 4 changes to a silicon oxide film in the process of O ₂ -RIE, it has a high resistance.

In this pattern forming method, since the formation of the silylated portion serving as a pattern occurs on the resist surface, it is possible to realize a high resolution by using a thin resist effectively.

(B) Further, the gate electrode of the transistor constituting the LSI has been reduced to 0.35 μm at present, and further processing of the gate electrode of 0.25 μm class or 0.15 μm class is required in the future. It is becoming.

Incidentally, such fine processing largely depends on technological advances in photolithography and etching. A resist pattern or a silicon oxide film pattern is used as a mask for etching a gate electrode material such as polysilicon.

Since the latter is obtained by etching using a resist pattern as a mask, a technique for forming a fine resist pattern is ultimately important. 365n wavelength at present
Processing at a level of 0.35 μm is performed by photolithography using m (i-line of a mercury lamp).
At a finer 0.25 μm or 0.15 μm level, lithography using shorter wavelength light is more likely to be employed.

The ArF excimer laser beam has a wavelength of 193n.
Since m is extremely short, high resolution is expected. However, the light absorption of a normal resist material at this wavelength is too large, the pattern shape is not rectangular, and the merit of shortening the wavelength cannot be sufficiently exhibited. Therefore, it is difficult to form a single-layer resist process as in conventional lithography.

In order to solve such problems, it is generally considered effective to make the imaging resist layer thin regardless of the exposure wavelength. As a method using such a thin film resist, for example, “Journal of
Vaccum Science and Techn
ology, Vol. 16, No. 6,1979,1
620 to 1624 ".

As shown in FIGS. 3A to 3G, a lower resist film 12 is formed on a substrate 11 as a mask layer.
Is formed thereon, and a coating glass film 13 is formed thereon, and further thereon, for example, an ArF excimer laser resist film 14
And processing this multilayer structure. ArF
The thickness of the excimer laser resist film 14 is reduced in order to avoid shape deterioration due to light absorption. A resist pattern 15 is obtained by exposure to this, and the coated glass film 13 is processed by dry etching using this as a mask to obtain an etching mask 16 and the lower resist film 12 is dry-etched using this as a mask. Thus, a substrate processing mask 17 having a width of 0.15 μm can be obtained.

[0014]

However, some problems can be pointed out in the above-mentioned first prior art (A).

(1) First, swelling of the film. Since the silylation starts by the penetration of the silylating agent and its solvent into the resist film, swelling of the film is unavoidable. As a result, as described in the above-mentioned document, the silylation portion 4 serving as a pattern is formed. The profile deteriorates, and high-precision patterning becomes difficult.

(2) Secondly, it is difficult to remove the silylated portion 4 formed on the surface layer of the photoresist film 2. The silylation portion 4 becomes unnecessary after O ₂ -RIE, but cannot be removed by ordinary plasma ashing or wet removal such as sulfuric acid-hydrogen peroxide solution, and is likely to cause a pattern defect. Therefore, development of a surface reaction process that does not swell and is easy to peel off after the process has been desired.

[0017] Some problems can also be pointed out in the above-mentioned second conventional technique (B).

That is, in order to obtain a high resolution by ArF excimer laser lithography, the resist must be thinned, so that a three-layer resist process must be employed. In this method, a lower resist film 12, a coated glass film 13, an ArF excimer laser resist film 14
Formation, photolithography of ArF excimer laser resist film 14, coated glass film 13 and lower resist film 1
A total of six steps, ie, two etching steps, must be performed, which involves an increase in the number of steps. This leads to an increase in device production cost (throughput, yield), which is not preferable.

Therefore, development of a method (two steps of resist coating and photolithography) which can be formed by one photolithography like the existing resist process has been strongly desired.

Therefore, a first object of the present invention is to provide
It is an object of the present invention to provide a method for forming a pattern of a semiconductor device having a surface reaction process which has no swelling and is easy to peel off after the process.

Therefore, a second object of the present invention is to provide
It is an object of the present invention to provide a method for forming a pattern of a semiconductor device, which can eliminate the problems described above, reduce the number of steps, and reduce the device production cost.

[0022]

SUMMARY OF THE INVENTION The present invention, in order to achieve the above object, the pattern formation method of (1) a semi-conductor device, Germa
, Monoalkylgermane, dialkylgermane, tri
From among alkyl germanes or tetraalkyl germanes
Plasma vapor phase growth using selected germanes as source gas
Forming depositing a polygermane film on the work board, to the polygermanes film, ArF excimer laser under an atmosphere containing oxygen, a latent image is subjected to exposure by an electron beam or X-ray by law process and, by dry etching using a halogen-based gas, corresponding to polygermanes of the port <br/> Rigeruman film and the unexposed portion is unexposed portion of
It said include removing the processed substrate portion, the to
It is characterized by.

(2) In the method for forming a pattern of a semiconductor device, a step of depositing a polygermane film on a substrate to be processed
And an atmosphere containing oxygen with respect to the polygerman film.
Exposed by ArF excimer laser, electron beam or X-ray below
Forming a latent image by performing a light, chlorine, bromine, chloride or any one, or mixtures of two or more kinds of bromide
Dry etching using halogen-based gas
The polygermane film which is an unexposed portion and the unexposed portion
The substrate to be processed corresponding to the polygerman film of the light section
And removing.

[0024] (3) above (1) or (2) In the pattern forming method of the semiconductor device according the pre-Symbol exposure light already polygermane film, nitric acid, sulfuric acid, one compound of sulfuric acid and hydrogen peroxide It is removed by class or two kinds or more mixed acid
It is characterized by.

(4) In the method for forming a pattern of a semiconductor device, it is preferable that the silane, the monoalkylsilane, the dialkylsila
Of trialkylsilane or tetraalkylsilane
Plasma gas phase using silanes selected from among as source gas
Forming depositing a polysilane film on the work board by a deposition method, to the polysilane layer, ArF excimer laser under an atmosphere containing oxygen, a latent image is subjected to exposure by an electron beam or X-ray performs a process, a dry etching using a halogen-based gas, to correspond to the port <br/> Rishiran film and polysilane film of the unexposed portion is unexposed portion
Wherein the step of removing the substrate to be processed portion that, to include
Features.

[0026] (5) In the pattern forming method of the above (4) The semiconductor device according, the halogen-based gas is a chlorine, bromine, chloride, either one, or mixtures of two or more kinds of fluoride or bromide There is a feature.

[0027]

According to the pattern forming method of action (A) The semiconductor device of the present invention, as shown in FIG. 1 as a substrate to be processed (a),
Silicon oxide film 2 2 on the silicon substrate 2 1, further tungsten film 2 3 used as laminated thereon.

Next, as shown in FIG. 1B , trimethylgermane [(CH ₃ ) ₃ Ge is placed on the substrate to be processed.
By plasma CVD using H] as a raw material gas (chemical vapor deposition) method, to deposit a polygermane film 2 4.

Next, as shown in FIG. 1C , reduction projection exposure is performed by using an ArF excimer laser in an oxygen atmosphere to form a latent image. This latent image is to polygermanes film 2 4 becomes poly gel Miro hexane film 2 5 photoexcited oxidized.

Next, as shown in FIG. 1 (d), by plasma etching using a mixed gas of chlorine and oxygen, the polygermane film 2 4 and the tungsten film 2 3 in succession etched in this order, obtaining a tungsten pattern 2 6.

Next, as shown in FIG. 1 (e), poly gel Miro hexane film 2 5 remaining on the tungsten pattern 2 6
Is dissolved in fuming nitric acid and dissolved and removed.

[0032] In the pattern forming process of the semiconductor device, since the poly gel Milo hexane film 2 5 a pattern is formed by photo-oxidation, essentially swell Unlike processes that use solvent can not occur. Polygel myloxane membrane
2 5 has a resistance to the plasma, whereas the polygermanes film 2 4 is unexposed portion, is comparable readily etched and the tungsten film 2 3 underlying. Polygermanes film 2 4 In this example is formed of trimethyl germane, but this addition in dimethyl germane [(CH _{3) 2} GeH _2], other alkyl germane, such as tetramethyl germane [(CH _{3) 4} Ge] Can also be used.

The photoexcited oxidation of the polygermane film 24 may use an energy ray other than an ArF excimer laser as long as it can excite the Ge—Ge bond of polygermane. Such examples include a fluorine excimer laser, an electron beam, an X-ray, and the like. Furthermore, the poly gel Miro hexane film 2 5 is dissolved in fuming nitric acid does not dissolve silylated resist (the silicon dioxide does not react with this is why) it with the very different process advantages It is.

[0034] (B-1) According to the pattern forming method of the semiconductor device of the present invention, as shown in FIG. 4 (a), as the substrate to be processed, a gate oxide film 32 on the n-type silicon substrate 31 A polysilicon film 33 serving as a gate electrode thereon
And a layered structure of a tungsten silicide film 34 (polycide structure 35) is used.

Next, as shown in FIG. 4B , trimethylsilane [(CH ₃ ) ₃ Si
H] as a source gas to deposit a polysilane film 36 by a plasma CVD (chemical vapor deposition) method.

Next, as shown in FIG. 4C, a latent image 37 is formed by performing reduced projection exposure using an ArF excimer laser in an oxygen atmosphere. The latent image 37 is obtained by photoexcited oxidation of the polysilane film 36 to form polysiloxane.

Next, as shown in FIG. 4D , the polysilane film 36 and the polycide film 35 are successively etched in this order by plasma etching using a mixed gas of chlorine and oxygen to form a polycide electrode TEG pattern. 3
Get 8.

In the pattern forming process of this semiconductor device, the polysiloxane portion formed by photo-oxidation with an ArF excimer laser has resistance to the above-mentioned plasma, while the unexposed portion of the polysilane film 36 is Etching is as easy. Also, the polysilane film 3
6, although formed from trimethylsilane in this example, the addition to Jimechirushira emissions [(CH _{3) 2} Si
Other alkylsilanes such as H ₂ ] and tetramethylsilane [(CH ₃ ) ₄ Si] can also be used.

[0039] (B-2) According to the pattern forming method of the semiconductor device of the present invention, as shown in FIG. 5 (a), a silicon thermal oxide film 4 on the silicon substrate 41 as a substrate to be processed
2 and a BPSG film 43 and an aluminum film 44 thereon
Is used.

Next, as shown in FIG. 5B , plasma CVD using trimethylsilane [(CH ₃ ) ₃ SiH] as a source gas in the same manner as in (B-1) above, on the substrate to be processed. A polysilane film 45 is deposited by (chemical vapor deposition).

Next, as shown in FIG. 5C , reduction projection exposure is performed using an ArF excimer laser in an oxygen atmosphere to form a latent image 46.

Next, as shown in FIG. 5D , the polysilane film 45 and the aluminum film 44 are successively etched in this order by plasma etching using boron tribromide to form an aluminum wiring TEG pattern 47.
Get.

(B-3) According to the method for forming a pattern of a semiconductor device of the present invention, as shown in FIG. 6A , first, a silicon nitride film 52 is formed on a silicon frame 51 as a substrate to be processed. A film in which a laminated structure of a coating glass film 53 and a tungsten film 54 is formed thereon is used.

Next, as shown in FIG. 6B , plasma CVD using trimethylsilane [(CH ₃ ) ₃ SiH] as a source gas in the same manner as in (B-2) above, on the substrate to be processed. A polysilane film 55 is deposited by (chemical vapor deposition).

Next, as shown in FIG. 6C , drawing is performed while flowing an oxygen gas over the substrate surface using an EB exposure apparatus equipped with a gas introduction system (see FIG. 7) to form a latent image 56. To form

Next, as shown in FIG. 6 (d), the plug's Ma etching a mixed gas of chlorine and oxygen, the polysilane film 55 and the tungsten film 54 in succession etched in this order, X-rays absorption The body pattern 57 is obtained.

[0047]

Embodiments of the present invention will be described below in detail with reference to the drawings. However, the numerical conditions such as used materials and their amounts, processing time, processing temperature, film thickness and the like mentioned in the following description are only preferred examples within the scope of the present invention. Therefore, it is not limited only to these conditions.

FIG. 1 is a sectional view showing a pattern forming step of a semiconductor device according to a first embodiment of the present invention.

[0049] (1) First, as shown in FIG. 1 (a), as the substrate to be processed, a silicon oxide film 2 2 (0.5 [mu] m thick) on the silicon substrate 2 1, further tungsten film thereon 2 3 (0.8 μm thick) is used.

(2) Next, as shown in FIG. 1B, the substrate to be processed is placed in a parallel plate type plasma polymerization apparatus.
Trimethyl germane [(CH _{3) 3} GeH] as the raw material gas, the gas flow rate 20 sccm, rf power density 0.12 W / cm ^2, and generates by polygermanes film 2 4 (plasma polymerization under the conditions of gas pressure 50 Pa,
(Having the same meaning as a plasma CVD film) is formed to a thickness of 0.1 μm.

(3) Next, as shown in FIG. 1 (c), the substrate was placed on an ArF excimer laser stepper (reduction ratio 1/20, aperture ratio NA 0.5
5) was used to perform the reduction projection exposure at an exposure amount 150 mJ / cm ^2, to form a latent image 2 5. This latent image 2 5 is a polygermanes film 2 4 becomes poly gel Miro hexane film 2 5 photoexcited oxidized according to the following equation.

[0052]

Embedded image (4) Next, as shown in FIG. 1 (d), chlorine and oxygen are each added at 50 scc using a magnetron etching apparatus.
m, 50 sccm, rf power 200 W, gas pressure 10
polygermanes film 2 4 mTorr, followed by etching the tungsten film 2 3 (amount of overetching 100
%). When the obtained tungsten pattern 2 6 was observed by SEM length measuring machine, the pattern of 0.10μm were resolved. When this was observed by a cross-sectional SEM, it was found to have a vertical cross-sectional shape.

(5) Next, as shown in FIG.
Poly gel on the tungsten pattern 2 6 Miro hexane film 2
98% heated to 100 ° C. to remove 5
After being immersed in sulfuric acid for 15 minutes, it is washed with pure water for 15 minutes. When the resulting substrate was to prepare a cross-sectional SEM sample observation, poly gel Miro hexane film 2 5 was completely removed.

[0054] In this process, since the poly gel Milo hexane film 2 5 a pattern is formed by photo-oxidation, essentially swell Unlike processes that use solvent can not occur. Poly gel Miro hexane film 2 5 has a resistance to the plasma, whereas, polygermane film 2 4 is unexposed portion
Is comparable readily etched and the tungsten film 2 3 underlying. Polygermanes film 2 4, although formed from trimethyl germane in this example, the addition of dimethyl germane [(CH _{3) 2} GeH _2], other alkyl, such as tetramethyl germane [(CH _{3) 4} Ge] Germanes can also be used.

[0055] Further, photoexcitation oxidation of polygermane film 2 4, if the wavelength that can excite the Ge-Ge bonds polygermane, may be used with an energy beam except ArF excimer laser. Such examples include a fluorine excimer laser, an electron beam, an X-ray, and the like. Furthermore, the poly gel Miro hexane film 2 5 is dissolved in fuming nitric acid does not dissolve silylated resist (the silicon dioxide does not react with this is why) it with the very different process advantages It is.

FIG. 4 is a sectional view showing a pattern forming step of a semiconductor device according to a second embodiment of the present invention.

(1) First, as shown in FIG. 4A, as a substrate to be processed, a gate oxide film 32 (5 nm thick) is formed on an n-type silicon substrate 31, and a poly oxide film serving as a gate electrode is formed thereon. A film having a laminated structure (polycide film 35) of a silicon film 33 (0.2 μm thick) and a tungsten silicide film 34 (0.2 μm thick) is used.

(2) Next, as shown in FIG. 4B, the substrate to be processed is placed in a parallel plate type plasma polymerization apparatus.
A polysilane film 36 (generated by plasma polymerization and formed by plasma polymerization under the conditions of a trimethylsilane gas flow rate of 20 sccm, an rf power density of 0.12 W / cm ² , and a gas pressure of 50 Pa using trimethylsilane [(CH ₃ ) ₃ SiH] as a source gas). Is formed to a thickness of 0.1 μm.

(3) Next, as shown in FIG. 4C, this substrate was placed on an ArF excimer laser stepper (reduction ratio 1/20, aperture ratio NA 0.5
By using 5), reduction projection exposure is performed at an exposure amount of 200 mJ / cm ² to form a latent image 37 of a TEG pattern. The latent image 37 is obtained by photo-excited oxidation of the polysilane film 36 into polysiloxane according to the following equation.

[0060]

Embedded image (4) Next, as shown in FIG. 4 (d), using a mug Ne Tron etching apparatus, chlorine, oxygen, respectively 50scc
m, 50 sccm, rf power 200 W, gas pressure 10
Polysilane film 36 at mTorr, followed by polycide film 3
5 is etched, and the polycide electrode TEG pattern 38 is etched.
Is obtained (100% overetching). Observation of the obtained polycide electrode TEG pattern 38 with a SEM length measuring machine revealed that the same pattern of 0.10 μm was resolved. When this was observed by a cross-sectional SEM, it was found to have a vertical cross-sectional shape.

In the pattern forming process of this semiconductor device, the polysiloxane portion formed by photo-oxidation with an ArF excimer laser has resistance to the above-mentioned plasma, while the polysilane film 36, which is the unexposed portion, is Etching is as easy as film 35. Polysilane film 3
6, although formed from trimethylsilane in this example, the addition to Jimechirushira emissions [(CH _{3) 2} Si
Other alkylsilanes such as H ₂ ] and tetramethylsilane [(CH ₃ ) ₄ Si] can also be used.

An important point of the process described here is to form a latent image 37 by photoexcited oxidation of the polysilane film 36 deposited by plasma polymerization, and in particular, at a wavelength that can excite the Si—Si bond of the polysilane. If there is, A
Energy rays other than the rF excimer laser may be used. Such examples include a fluorine excimer laser, an electron beam, an X-ray, and the like. These are expected as light sources for short wavelength lithography and are under development.

It should be noted that another gas system can be used in the etching step of the second embodiment. This will be described with reference to FIGS. 4A to 4D of the second embodiment.

That is, a gate oxide film 32 formed on an n-type silicon substrate 31 and a polycide film 35 serving as a gate electrode formed thereon are used. A polysilane film 36 is deposited thereon by plasma CVD using trimethylsilane [(CH ₃ ) ₃ SiH] as a source gas, and reduced projection exposure is performed using an ArF excimer laser in an oxygen atmosphere to form a latent image 37 (polysiloxane). Consisting of).

Next, etching is performed under etching conditions different from those in the second embodiment. That is, the polysilane film 36 and the polycide film 35 are successively etched in this order by plasma etching using a mixed gas of sulfur hexafluoride and oxygen to obtain a polycide electrode TEG pattern 38.

Here, more specifically, the polysilane film 3
6 and the polycide film 35 are continuously etched by sulfur hexafluoride and oxygen at 40 sccm, 10 sccm and r, respectively.
f power 200W, gas pressure 5mTorr, substrate temperature-
Performed at 40 ° C. (100% overetching). When the obtained electrode pattern was evaluated by SEM length measurement,
A 0.1 μm pattern was resolved.

With this configuration, the same effects as in the second embodiment can be obtained, but since other than fluorine can be used as the halogen-based gas, there is room for selecting conditions according to the actual conditions of the process.

Next, a third embodiment of the present invention will be described.

The pattern forming process of the semiconductor device of the present invention described above can be applied to other metal working. That is, the present invention is effective when applied to various metal wirings such as aluminum, tungsten, and copper of LSI. In particular, in order to obtain the fine wiring required for high-speed and high-integration LSI, it is necessary to increase the etching selectivity with respect to the metal to be processed. It is better to use an inorganic mask such as polysiloxane. In the third embodiment, such an example will be described.

FIG. 5 is a sectional view showing a pattern forming step of a semiconductor device according to a third embodiment of the present invention.

(1) First, as shown in FIG. 5A, a silicon thermal oxide film 42 (7 nm thick) is formed on a silicon substrate 41 as a substrate to be processed, and a BPSG film 43 is formed thereon.
(0.7 μm thick) and the aluminum film 44 (0.6 μm
Thickness) is used.

(2) Next, as shown in FIG.
The substrate to be processed is placed in a parallel plate type plasma polymerization apparatus, and a trimethylsilane gas flow rate of 20 sccm using trimethylsilane [(CH ₃ ) ₃ SiH)] as a raw material gas and an rf power are set thereon in the same manner as in the second embodiment. Density 0.
Under conditions of 12 W / cm ² and gas pressure of 50 Pa, a polysilane film 45 (formed by plasma polymerization and having the same meaning as a plasma CVD film) is formed to a thickness of 0.1 μm.

(3) Next, as shown in FIG. 5 (c), the substrate was placed on an ArF excimer laser stepper (reduction ratio 1/5, aperture ratio NA 0.5) while flowing oxygen through the surface. Then, reduction projection exposure is performed at an exposure amount of 200 mJ / cm ² to form a latent image 46 of a TEG pattern.

(4) Next, as shown in FIG. 5D, boron tribromide is
0 sccm, rf power 600 W, gas pressure 0.1 To
rr conditions, the polysilane film 45 and the aluminum film 4
4 are successively etched in this order to obtain an aluminum wiring TEG pattern 47. (Overetching amount 50%) Observation of the obtained aluminum wiring TEG pattern 47 with a SEM length measuring machine revealed that it was 0.30 μm.
The same pattern was resolved. Further, when this was viewed with a cross-sectional SEM, the cross-sectional shape was almost vertical.

In the third embodiment, the case where the present invention is applied to the aluminum wiring of the LSI is described. However, the technique of the present invention can be applied to the case where the etching conditions are changed.

Hereinafter, description will be made with reference to FIG.

As shown in FIGS. 5A to 5D, a silicon thermal oxide film 42 is formed on a silicon substrate 41 and a B
A film having a laminated structure of the PSG film 43 and the aluminum film 44 is used. Trimethylsilane [(CH ₃ ) ₃ S] is formed on the substrate to be processed in the same manner as in the third embodiment.
iH)] is used as a source gas to deposit a polysilane film 45 by plasma CVD (chemical vapor deposition). Next, reduction projection exposure is performed using an ArF excimer laser in an oxygen atmosphere to form a latent image 46. Next, the polysilane film 45 and the aluminum film 44 are successively etched in this order by plasma etching using chlorine.
An aluminum wiring pattern 47 is obtained. Here, more specifically, using an ECR plasma etching apparatus, chlorine 100 sccm, microwave power 300 W, rf power 150 W, gas pressure 2 mTorr, substrate temperature -50
Polysilane film 45 and aluminum film 44 under the condition of
Are successively performed in this order to obtain an aluminum wiring TEG pattern 47 (overetching amount 100%). When the obtained aluminum wiring TEG pattern 47 was observed with a SEM length measuring machine, it was found to be 0.30 μm
The same pattern was resolved. In addition, this is
As a result, the cross section was almost vertical.

Hereinafter, a fourth embodiment of the present invention will be described.

The wiring processing method described in the third embodiment is also effective when applied to the manufacture of an X-ray mask used for X-ray lithography.

Hereinafter, the manufacture of an X-ray mask used for X-ray lithography will be described as a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a pattern forming step of a semiconductor device according to a fourth embodiment of the present invention.

(1) First, as shown in FIG. 6A, a substrate to be processed is a silicon frame 51 (thickness of 25 mm square, the center of a silicon substrate having a diameter of 3 inches and a thickness of 2 mm being removed by etching). The silicon nitride film 52 (2 μm
Thickness) and a heat-treated coated glass film 53 (0.
A film having a laminated structure of 3 μm thick) and a tungsten film 54 (0.5 μm thick) is used.

(2) Next, as shown in FIG. 6B, the substrate to be processed is placed in a parallel plate type plasma polymerization apparatus.
Further, trimethylsilane [(CH ₃ ) ₃ SiH] was used as a raw material gas in the same manner as in the third embodiment, the flow rate of the trimethylsilane gas was 20 sccm, and the rf power density was 0.1.
Under the conditions of ² W / cm ² and a gas pressure of 50 Pa, a polysilane film 55 (formed by plasma polymerization and synonymous with a plasma CVD film) having a thickness of 0.05 μm is formed.

(3) Next, in FIG. 6 (c), an EB exposure apparatus equipped with a gas introduction system as shown in FIG. 7 is used to supply oxygen gas 62 from the gas introduction nozzle 61 to the substrate surface. , And a latent image 56 is formed. Conditions are as follows: acceleration voltage 30 kV, oxygen gas flow rate 5 scc
m, sample chamber base pressure 5 × 10 ⁻⁷ Torr, exposure amount 50
μC / cm ² .

(4) Next, as shown in FIG. 6D, using a magnetron etching apparatus, the flow rates of chlorine and oxygen are respectively 20 sccm and 20 sccm, and the pressure is 7 mTorr.
The polysilane film 55 and the tungsten film 54 are successively etched in this order under the conditions of r and rf power of 200 W to obtain an X-ray absorber pattern 57 (overetching amount 100%). Obtained X-ray absorber pattern 5
When No. 7 was observed with a SEM length measuring apparatus, a 0.05 μm line and space pattern was resolved. When this was observed by a cross-sectional SEM, it was found to have a substantially vertical cross-sectional shape.

In general, in X-ray mask absorber processing using an inorganic mask, as shown in FIG. 8, in EB exposure on a heavy metal such as tungsten, incident electrons are reflected by a tungsten film 63 and a resist film is formed. The exposure range 64 is smaller than the design exposure range 65 by the proximity effect exposure range 6.
6, the resolution is reduced.
For this reason, a method of reducing the thickness of the resist film 64 or preventing a decrease in resolution by a multilayer resist method or the like is adopted.

Also in this embodiment, as shown in FIG. 9, the exposure range by the scattered electrons is expanded, that is, the mask formation range 72 on the tungsten film 70 is expanded to the exposure range 73 by the proximity effect. Occurs on the surface of the polysilane film in contact with the oxygen gas, and is therefore limited only to the cross section at the time of incidence of the electron beam. There is substantially no effect of scattered electrons, and extremely high resolution can be realized. 7
1 is a resist film.

The present invention is not limited to the above-described embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0089]

As described above, according to the present invention, the following effects can be obtained.

(A) According to the method for forming a pattern of a semiconductor device of the present invention, since a polygermyloxane film to be a pattern is formed by photo-oxidation, swelling can occur essentially unlike a process using a solvent. Absent. The polygermyloxane film is resistant to plasma, while the unexposed polygermane film is as easily etched as the underlying tungsten film. For the photoexcited oxidation of the polygermane film, an energy ray other than the ArF excimer laser may be used as long as the wavelength can excite the Ge—Ge bond of the polygermane. Furthermore, the fact that the polygermyloxane film dissolves in fuming nitric acid is significantly different from the fact that the silylated resist does not dissolve, and is an advantage in terms of process.

[0091] Thus, it utilizes the photooxidation of polygermane film patterning, unlike the patterning using a solvent, it is essentially score swelling without 0.1
A fine pattern of μm can be formed.

Further, the unnecessary polygel myloxane film as an etching mask can be dissolved and removed with sulfuric acid. Therefore, damage to the underlying substrate can be avoided, and occurrence of pattern defects due to particles or the like can be avoided.

(B-1) According to the method for forming a pattern of a semiconductor device of the present invention, the polysiloxane portion formed by photo-oxidation with an ArF excimer laser has resistance to plasma, while it is an unexposed portion. The polysilane film can be etched as easily as the underlying polycide film.

As described above, the problem of the prior art that the number of steps is increased as a result of employing the three-layer resist process to obtain high resolution by ArF excimer laser lithography can be solved.

That is, a latent image can be formed in the same two steps of forming a polysilane film and photolithography thereof.
Since the etching of the polysilane film, which is the step of forming the mask pattern, and the etching of the subsequent polycide structure are continuous, the number of steps is the same even if the processing step of the substrate to be processed is included.

(B-2) According to the pattern forming method for a semiconductor device of the present invention, an etching process using an inorganic mask can be realized without increasing the number of steps.

In wiring processing using an inorganic mask, for example, non-doped silica glass, since the non-doped silica glass itself does not have a pattern forming function, a resist mask is used to etch the non-doped silica glass using the resist mask. In general, the number of steps increases as compared with the case. However, in the present invention, the number of steps does not increase even if the processing steps of the substrate to be processed are included.

(B-3) According to the method for forming a pattern of a semiconductor device of the present invention, in particular, in the processing of an X-ray mask absorber using an inorganic mask, the same effect as (B-2) can be obtained. Can be.

Further, extremely high resolution can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pattern forming step of a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a pattern forming step of a conventional first semiconductor device.

FIG. 3 is a cross-sectional view of a pattern forming step of a second conventional semiconductor device.

FIG. 4 is a sectional view showing a pattern forming step of a semiconductor device according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a pattern forming step of a semiconductor device according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing a pattern forming step of a semiconductor device according to a fourth embodiment of the present invention.

FIG. 7 shows a process of forming a latent image by drawing while using an EB exposure apparatus having a gas introduction system according to a fourth embodiment of the present invention and flowing an oxygen gas from a gas introduction nozzle to a substrate surface. FIG.

FIG. 8 shows a conventional EB on a heavy metal such as tungsten.
It is a figure showing an exposure state.

FIG. 9 is a view showing an EB exposure state on a heavy metal such as tungsten according to a fourth embodiment of the present invention.

[EXPLANATION OF SYMBOLS] 2 1,31,41 silicon substrate 2 second silicon oxide film 2 3,54, 63, 70 tungsten film 2 4 polygermanes film 2 5 poly gel Milo hexane film (latent) 2 6 tungsten pattern 32 gate Oxide film 33 Polysilicon film 34 Tungsten silicide film 35 Stacked structure (polycide structure) 36, 45, 55 Polysilane film 37, 46, 56 Latent image 38 Polycide electrode TEG pattern 42 Silicon thermal oxide film 43 BPSG film 44 Aluminum film 47 Aluminum wiring TEG pattern 51 Silicon frame 52 Silicon nitride film 53 Coated glass film 57 X-ray absorber pattern 61 Gas introduction nozzle 62 Oxygen gas 64, 71 Resist film 65 Design exposure range 66, 73 Exposure range by proximity effect 72 Mask formation range 73 Exposure range

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI H01L 21/30 569H (58) Investigated field (Int.Cl. ⁷ , DB name) H01L 21/3213 H01L 21/3205 H01L 21 / 321 H01L 21/768 H01L 21/027 H01L 21/302 G03F 1/16 G03F 7/075 511 G03F 7/26 511

Claims (5)

(57) [Claims] (1) Germanium, monoalkylgermane,
Dialkylgermane, trialkylgermane or tetra
Germanic materials selected from alkyl germanes as raw materials
By plasma vapor deposition method to scan depositing a polygermane film on the work board, (b) the relative polygermanes film, ArF excimer laser under an atmosphere containing oxygen, an electron beam or X lines forming a latent image is subjected to exposure by a line, a dry etching using (c) a halogen-containing gas
There, the polygermanes film and the unexposed a unexposed part
The pattern formation method of a semiconductor device which comprises the steps of dividing <br/> removed by the substrate to be processed portion corresponding to polygermanes light unit. (A) depositing a polygermane film on a substrate to be processed;
And (b) an atmosphere containing oxygen with respect to the polygermane film.
By ArF excimer laser, electron beam or X-ray under
Use a step of forming a latent image is subjected to exposure, chlorine, bromine, a halogen-based gas consisting of any one such <br/> or a mixture of two or more kinds of chloride or bromide (c)
Dry etching, and
Compatible with germane film and polygermane film in the unexposed area
The pattern formation method of a semiconductor device which comprises a step of removing the workpiece substrate portion, the to. 3. A pattern formation method of a semiconductor device according to claim 1 or 2 wherein, prior Symbol exposure light already polygermane film
The nitric acid, sulfuric acid, pattern formation method of a semiconductor device, and removing by one class <br/> or two kinds or more mixed acid of a compound of sulfuric acid and hydrogen peroxide. (A) silane, monoalkylsilane, dia
Rukirushiran, Toriarukirushiranma other Tetoraaruki
Using silanes selected from
Been depositing a polysilane film on the work board by plasma vapor deposition, relative to (b) the polysilane layer, ArF excimer laser under an atmosphere containing oxygen, the exposure by an electron beam or X-ray forming a latent image Te, by dry etching using (c) a halogen-based gas, the polysilane film and the unexposed a unexposed part
Of the substrate to be processed corresponding to a part of the polysilane film is removed.
The pattern formation method of a semiconductor device which comprises the steps, a to. 5. A pattern forming method of a semiconductor device according to claim 4, wherein the halogen-based gas is a chlorine, bromine, chloride, 1 kinds either fluoride or bromide or 2 kinds <br/> more A method for forming a pattern of a semiconductor device, comprising a mixture.