Dry etching method for carbon atom-containing film
By using mixed gas containing oxygen and sulfur dioxide and oxygen-containing material masks in carbon atomic film etching, the problems of excessive mask etching rate and insufficient accuracy are solved, and efficient anisotropic etching and mask stability are achieved .
Patent Information
- Application Number
- CN202380037841.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-07-22
- Filing Date
- 2023-07-20
- Publication Date
- 2024-12-13
AI Technical Summary
In the prior art, when dry etching of the carbonaceous layer, the etching rate of the mask is higher than that of the carbonaceous layer, resulting in the possibility of collapse of the mask and it is difficult to achieve high-precision anisotropic etching.
Using a mask containing oxygen-containing material, and using a mixed gas containing oxygen and sulfur dioxide during the etching process, the etching gas is generated by plasma generation, and the carbon-containing atomic film is etched to ensure that the opening width of the mask is in the range of 10 to 150 nm. Within, anisotropic etching is preferred.
Prioritative anisotropic etching of carbon-containing atomic film is achieved, etching accuracy and speed are improved, mask collapse is avoided, and etch selectivity is enhanced.
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Figure CN119137715A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a dry etching method for a carbon atom-containing film. Background Art
[0002] In semiconductor integrated circuits, the miniaturization and stacking of components are developing. In the manufacture of semiconductor integrated circuits, the following technology is required, namely, using a mask such as a photoresist to pattern the etched film, and processing deep holes or grooves with a small opening and a large aspect ratio on the etched film with high precision and high speed.
[0003] As such a technique, for example, there is known a method described in Patent Document 1. This publication reports that machining accuracy can be improved by using a plasma gas of a mixed gas in which carbonyl sulfide is added to oxygen as an etching gas for a carbonaceous layer containing carbon.
[0004] Previous technical literature
[0005] Patent Literature
[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-200459 Summary of the invention
[0007] Technical issues to be solved by the invention
[0008] However, the method described in the above-mentioned Patent Document 1, when dry etching the carbonaceous layer, anisotropically etches the carbonaceous layer preferentially compared to the mask arranged on the carbonaceous layer, and there is room for improvement in this respect. Here, in the case where the etching rate of the mask arranged on the carbonaceous layer is greater than the etching rate of the carbonaceous layer, it is also possible to consider increasing the thickness of the mask. However, in this case, the mask may collapse due to etching.
[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a dry etching method for a carbon atom-containing film, which can anisotropically etch the carbon atom-containing film preferentially compared to a mask arranged on the carbon atom-containing film when dry etching the carbon atom-containing film.
[0010] Means for solving technical problems
[0011] The inventors of the present invention discovered that by configuring a mask including an oxygen-containing material as a mask configured on a carbon atom-containing film and making the opening width of the mask within a specific range, and by changing the additive gas in oxygen during etching of the carbon atom-containing film from carbonyl sulfide to sulfur dioxide, the above-mentioned problems can be unexpectedly solved, thereby completing the present invention.
[0012] That is, one aspect of the present invention provides a dry etching method for a carbon atom-containing film, which uses an etching gas to etch the carbon atom-containing film containing carbon atoms, and includes: a mixed gas introduction process, introducing a mixed gas containing at least oxygen and sulfur dioxide into an etching chamber configured with a structure, the structure having the carbon atom-containing film and a mask having a first opening; and an etching process, plasmaizing the mixed gas in the etching chamber to generate plasma gas, and using the plasma gas as the etching gas to etch the carbon atom-containing film of the structure to form a second opening, in the mixed gas introduction process, the mask contains an oxygen-containing material, and the width of the first opening of the mask is 10 to 150 nm.
[0013] According to the dry etching method of the carbon atom-containing film, when the carbon atom-containing film is dry-etched, the carbon atom-containing film can be anisotropically etched preferentially compared to the mask disposed on the carbon atom-containing film.
[0014] The width of the first opening of the mask may be 40 to 150 nm.
[0015] The first opening may be in the shape of a groove or a hole.
[0016] The above-mentioned carbon atom-containing film may contain amorphous carbon.
[0017] The oxygen-containing material contained in the mask may be silicon dioxide.
[0018] The carbon atom-containing film may have a thickness of 0.1 μm or more.
[0019] The carbon atom-containing film may have a thickness of 10.0 μm or less.
[0020] The thickness of the mask may be 0.01 times or more the thickness of the carbon atom-containing film.
[0021] The thickness of the mask may be 0.5 times or less of the thickness of the carbon atom-containing film.
[0022] In the mixed gas, the content rate of the sulfur dioxide in the total volume of the sulfur dioxide and the oxygen may be 20 to 40 volume %.
[0023] Effects of the Invention
[0024] According to the present invention, a dry etching method for a carbon atom-containing film is provided, which can anisotropically etch the carbon atom-containing film preferentially compared to a mask arranged on the carbon atom-containing film when dry etching the carbon atom-containing film. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1This is a cross-sectional view showing an example of a structure before the etching step in the dry etching method of the carbon atom-containing film of the present invention.
[0026] Figure 2 It means that the configuration has Figure 1 Schematic diagram of the etching chamber of the structure.
[0027] Figure 3 This is a cross-sectional view showing an example of a structure after an etching step in the dry etching method of a carbon atom-containing film of the present invention.
[0028] Figure 4 yes Figure 3 A partial enlarged view of the mask and the carbon atom-containing film.
[0029] Figure 5 This is a graph showing the results of plotting the etching selectivity with respect to the designed trench width of the mask in Examples 1 to 3 and Comparative Examples 1 to 3. DETAILED DESCRIPTION
[0030] Below, reference Figure 1 to Figure 4 Embodiments of the dry etching method of a carbon atom-containing film of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.
[0031] Figure 1 is a cross-sectional view showing an example of a structure before an etching step in the dry etching method of a carbon atom-containing film of the present invention, Figure 2 It means that the configuration has Figure 1 Schematic diagram of the etching chamber of the structure, Figure 3 is a cross-sectional view showing an example of a structure after an etching step in the dry etching method of a carbon atom-containing film of the present invention, Figure 4 yes Figure 3 A magnified partial view of the carbon atom-containing film.
[0032] The dry etching method of the carbon-containing film of the present invention is a method for etching the carbon-containing film 20 containing carbon atoms by using an etching gas, which comprises: a mixed gas introduction step, introducing a mixed gas G containing at least oxygen and sulfur dioxide into an etching chamber 1 provided with a structure 100, the structure 100 having the carbon-containing film 20 and a mask 30 having a first opening 31; and an etching step, converting the mixed gas G into plasma in the etching chamber 1 to generate a plasma gas, and etching the carbon-containing film 20 of the structure 100 using the plasma gas to form a second opening 21 (refer to Figure 1 to Figure 3 ). In addition, in the mixed gas introduction step, the mask 30 includes an oxygen-containing material, and the width L1 of the first opening 31 of the mask 30 is 10 to 150 nm.
[0033] According to the above-mentioned dry etching method of the carbon atom-containing film, the mask 30 configured on the carbon atom-containing film 20 during etching is set to a film containing an oxygen-containing material, and the width L1 of the first opening portion 31 of the mask 30 is set within a specific range, while the carbon atom-containing film 20 is etched with a plasma gas of a mixed gas G containing oxygen and sulfur dioxide. Therefore, when the carbon atom-containing film 20 is dry-etched, the carbon atom-containing film 20 can be anisotropically etched preferentially compared to the mask 30 configured on the carbon atom-containing film 20.
[0034] Hereinafter, the mixed gas introduction step and the etching step will be described in detail.
[0035] <Mixed gas introduction process>
[0036] The structure 100 includes a carbon atom-containing film 20 containing carbon atoms and a mask 30 having a first opening 31. Figure 1 As shown, the structure 100 may further include a support 10 supporting the carbon atom-containing film 20. In this case, the carbon atom-containing film 20 is disposed between the mask 30 and the support 10. Furthermore, the structure 100 may further include an intermediate film (not shown) between the support 10 and the carbon atom-containing film 20.
[0037] (Support)
[0038] The support 10 is not particularly limited as long as it is a member that supports the carbon atom-containing film 20. Examples of materials constituting the support 10 include silicon and germanium. Silicon is preferred. In this case, the durability under high pressure is further improved due to the wide band gap.
[0039] The thickness of the support 10 is not particularly limited, and may be 254 μm or more, or 520 μm or more. When the thickness of the support 10 is 254 μm or more, the mechanical strength is further improved. In addition, the thickness of the support 10 may be 795 μm or less, or 725 μm or less. When the thickness of the support 10 is 795 μm or less, it is easy to cut the structure 100 into wafers of a specified size.
[0040] (Intermediate film)
[0041] As other intermediate films, silicon dioxide (SiO 2 ), silicon nitride (Si 3 N 4 ), amorphous silicon (a:Si) and polycrystalline silicon (poly:Si), etc.
[0042] (Carbon atom-containing film)
[0043] The carbon atom-containing film 20 is not particularly limited as long as it is a film containing carbon atoms. The carbon atom-containing film 20 may be an inorganic carbon film such as amorphous carbon, or an organic polymer film such as a resist film and a polyimide film. If the carbon atom-containing film 20 is amorphous carbon, the etching selectivity (i.e., the ratio of the etching rate Vc of the carbon atom-containing film to the etching rate Vm of the mask) can be increased when the pattern is transferred to the carbon atom-containing film 20.
[0044] The thickness of the carbon atom-containing film 20 is not particularly limited, and can be greater than 0.1 μm, or greater than 0.5 μm. When the thickness of the carbon atom-containing film 20 is greater than 0.1 μm, in the case where an intermediate film is stacked under the carbon atom-containing film 20 as an etched layer, the carbon atom-containing film 20 can function as a mask for the etched layer. In addition, the thickness of the carbon atom-containing film 20 can be less than 10 μm, or less than 5 μm. When the thickness of the carbon atom-containing film 20 is less than 10 μm, the carbon atom-containing film 20 is not easy to collapse after etching.
[0045] (Mask)
[0046] The mask 30 has a first opening 31 for allowing the etching gas to pass through and be guided to the carbon atom-containing film 20. The shape of the first opening 31 is not particularly limited, and may be, for example, a groove or a hole. The mask 30 contains an oxygen-containing material. At this time, the etching rate of the mask 30 can be relatively slower than the etching rate of the carbon atom-containing film 20, and when the carbon atom-containing film 20 is dry-etched, the carbon atom-containing film 20 can be anisotropically etched preferentially compared to the mask 30 disposed on the carbon atom-containing film 20.
[0047] Examples of the oxygen-containing material include silicon dioxide, silicon oxynitride, etc. Among them, silicon dioxide is preferred from the viewpoint of economic efficiency.
[0048] The width L1 of the first opening 31 is the design width of the first opening 31, and the width L1 of the first opening 31 is 10 to 150 nm. The width L1 of the first opening 31 is 10 nm or more, so that the generated plasma can easily etch the carbon atom-containing film 20. The width L1 of the first opening 31 is 150 nm or less, so that when the carbon atom-containing film 20 is dry-etched, the carbon atom-containing film 20 can be anisotropically etched preferentially compared to the mask 30 disposed on the carbon atom-containing film 20.
[0049] The width L1 of the first opening 31 may be 40 to 150 nm, 50 to 150 nm, or 60 to 100 nm.
[0050] The thickness of the mask 30 is not particularly limited, and can be 0.01 times or more of the thickness of the carbon atom-containing film 20, or 0.1 times or more. When the thickness of the mask 30 is 0.01 times or more of the thickness of the carbon atom-containing film 20, anisotropic etching of the carbon atom-containing film can be performed. In addition, the thickness of the mask 30 can be 0.5 times or less of the thickness of the carbon atom-containing film 20, or 0.2 times or less. When the thickness of the mask 30 is 0.5 times or less of the thickness of the carbon atom-containing film 20, the carbon atom-containing film 20 is not easy to collapse after etching.
[0051] (Etching Chamber)
[0052] The etching chamber 1 is a container for etching the carbon atom-containing film 20 using a plasma gas obtained by converting a mixed gas G containing oxygen and sulfur dioxide into plasma, and constitutes a part of an etching apparatus.
[0053] Examples of the etching apparatus include a microwave ECR plasma etching apparatus, a capacitively coupled plasma (CCP) etching apparatus, an inductively coupled plasma (ICP) etching apparatus, but the etching apparatus is not limited thereto.
[0054] <Mixed gas introduction process>
[0055] (Mixed gas)
[0056] The mixed gas G contains oxygen and sulfur dioxide. The content of sulfur dioxide in the total volume of oxygen and sulfur dioxide is not particularly limited as long as it is greater than 0 volume %, and may be 20 to 40 volume %, or 25 to 35 volume %.
[0057] When the content of sulfur dioxide in the total volume of oxygen and sulfur dioxide is within a range of 20 to 40 volume %, the etching rate of the carbon atom-containing film 20 can be further effectively increased.
[0058] The flow rate of the mixed gas G when introduced into the etching chamber 1 can be 0.1 mL / min or more, 1 mL / min or more, or 10 mL / min or more. When the flow rate of the mixed gas G is 0.1 mL / min or more, ions and free radicals required for etching the carbon atom-containing film can be effectively generated.
[0059] The flow rate of the mixed gas G introduced into the etching chamber 1 may be 10000 mL / min or less, 1000 mL / min or less, or 100 mL / min or less. When the flow rate of the mixed gas G is 10000 mL / min or less, it is easy to maintain the vacuum degree of the etching device at a low pressure.
[0060] <Etching process>
[0061] The etching step is a step of converting the mixed gas G into plasma in the etching chamber 1 to generate plasma gas, and etching the carbon atom-containing film 20 of the structure 100 using the plasma gas to form the second opening 21. The structure 100 is converted into the structure 200 by the etching step.
[0062] (Pressure in the etching chamber)
[0063] The pressure in the etching chamber 1 during dry etching may be 0.1 mTorr to 100 Torr, or 0.1 mTorr to 100 mTorr. When the pressure in the etching chamber 1 is 0.1 mTorr to 100 mTorr, the second opening 21 can be excellently controlled in shape due to the low pressure.
[0064] (Antenna power)
[0065] When an inductively coupled plasma (ICP) etching device is used as the etching device, the antenna power is not particularly limited and may be 50 to 1000 W, 100 to 800 W, or 200 to 600 W. By setting the antenna power to 50 to 1000 W, the carbon atom-containing film 20 can be etched anisotropically at high speed.
[0066] (Bias power)
[0067] When an inductively coupled plasma (ICP) etching device is used as the etching device, the bias power is not particularly limited and may be 10 W or more, 25 W or more, or 50 W or more. By setting the bias power to 10 W or more, the aspect ratio of the second opening 21 can be easily increased.
[0068] Furthermore, the bias power may be 500 W or less, 300 W or less, or 200 W or less. By setting the bias power to 500 W or less, it is easy to appropriately control dry etching.
[0069] (Second opening)
[0070] The shape of the second opening 21 of the etched carbon atom-containing film 20 is the same as the shape of the first opening 31. That is, when the first opening 31 is a groove, the second opening 21 is also a groove, and when the first opening 31 is a hole, the second opening 21 is also a hole.
[0071] The aspect ratio of the second opening 21 of the carbon atom-containing film 20 after etching is not particularly limited, and may be, for example, 0.1-60, 1-40, 4-40, 5-40, or 5-25.
[0072] When the aspect ratio is 60 or less, the etching rate of the carbon atom-containing film 20 can be increased compared to the case where the carbon atom-containing film 20 is etched using a plasma gas containing a mixed gas G of oxygen and carbonyl sulfide. In addition, when a layer (lower layer) is provided on the side opposite to the mask 30 with respect to the carbon atom-containing film 20, since the aspect ratio is 0.1 or more, the carbon atom-containing film 20 can easily function as a mask when etching the lower layer, for example. As the lower layer, silicon dioxide (SiO 2 ), silicon nitride (Si 3 N 4 ), amorphous silicon (a:Si) and polycrystalline silicon (poly:Si), etc.
[0073] Here, the aspect ratio refers to the ratio (L2 / L1) of the depth (L2) of the second opening 21 to the design width (L1) of the first opening 31 in the cross section of the carbon atom-containing film 20 (see Figure 4 ). The design width L1 of the first opening 31 refers to the length of the first opening 31 along the interface between the carbon atom-containing film 20 and the mask 30 in the cross section of the mask 30. In the case where the first opening 31 of the mask 30 is a groove pattern, the cross section of the mask 30 refers to the cross section along the surface that is orthogonal to the long side direction of the groove and along the thickness direction of the mask 30. The depth of the second opening 21 refers to the length from the interface between the carbon atom-containing film 20 and the mask 30 to the bottom surface of the second opening 21 in the cross section of the carbon atom-containing film 20, and is the length along the thickness direction of the carbon atom-containing film 20.
[0074] Examples of analytical instruments for confirming etching performance include SEM (scanning electron microscope) and TEM (transmission electron microscope). The analytical instrument is not particularly limited as long as it is a device capable of confirming etching rate and bowing occurrence.
[0075] In addition, the gist of the present invention is as follows.
[0076] [1] A dry etching method for a carbon-containing film, which uses an etching gas to etch the carbon-containing film containing carbon atoms, comprising: a mixed gas introduction step, introducing a mixed gas containing at least oxygen and sulfur dioxide into an etching chamber configured with a structure, wherein the structure has the carbon-containing film and a mask having a first opening; and an etching step, wherein the mixed gas is plasmatized in the etching chamber to generate a plasma gas, and the plasma gas is used as the etching gas to etch the carbon-containing film of the structure to form a second opening, wherein in the mixed gas introduction step, the mask contains an oxygen-containing material, and the width of the first opening of the mask is 10 to 150 nm.
[0077] [2] The dry etching method for a carbon atom-containing film according to [1], wherein:
[0078] The width of the first opening of the mask is 40 to 150 nm.
[0079] [3] The dry etching method for a carbon atom-containing film according to [1] or [2], wherein:
[0080] The first opening is in the shape of a groove or a hole.
[0081] [4] The dry etching method for a carbon atom-containing film according to any one of [1] to [3], wherein:
[0082] The carbon atom-containing film includes amorphous carbon.
[0083] [5] The dry etching method for a carbon atom-containing film according to any one of [1] to [4], wherein:
[0084] The oxygen-containing material contained in the mask is silicon dioxide.
[0085] [6] The dry etching method for a carbon atom-containing film according to any one of [1] to [5], wherein:
[0086] The carbon atom-containing film has a thickness of 0.1 μm or more.
[0087] [7] The dry etching method for a carbon atom-containing film according to any one of [1] to [6], wherein:
[0088] The carbon atom-containing film has a thickness of 10.0 μm or less.
[0089] [8] The dry etching method for a carbon atom-containing film according to any one of [1] to [7], wherein:
[0090] The thickness of the mask is greater than or equal to 0.01 times the thickness of the carbon atom-containing film.
[0091] [9] The dry etching method for a carbon atom-containing film according to any one of [1] to [8], wherein:
[0092] The thickness of the mask is 0.5 times or less of the thickness of the carbon atom-containing film.
[0093]
[10] The dry etching method for a carbon atom-containing film according to any one of [1] to [9], wherein:
[0094] In the mixed gas, the content of the sulfur dioxide in the total volume of the sulfur dioxide and the oxygen is 20 to 40 volume %.
[0095] Example
[0096] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
[0097] [Example 1]
[0098] First, a stacked body composed of a Si substrate as a support and an amorphous carbon film (thickness: about 2400 nm) as a carbon atom-containing film was prepared. Furthermore, a silicon dioxide film (total thickness of the silicon film and the silicon dioxide film: about 350 nm) having a mask pattern as a first opening formed by photolithography and having a silicon film as a lower layer was arranged as a mask on the amorphous carbon film of the stacked body, and a 20 mm square structure (reference Figure 1 At this time, the mask pattern of the mask is a groove pattern, the groove design width (the design width of the first opening) L1 is 60nm, and the mask design width (the width of the entity part other than the first opening in the mask) W is set to 240nm (reference Figure 1 ). Then, the structure obtained as described above was attached to a wafer having a diameter of 150 mm and placed on a processing table in an etching chamber of an etching device. At this time, an inductively coupled plasma (ICP) etching device (product name "NLD6000", manufactured by ULVAC, Inc.) was used as an etching device.
[0099] Furthermore, dry etching of the amorphous carbon film was performed as follows. That is, the vacuum pressure in the etching chamber was set to 3.8 mTorr, the antenna power was set to 400 W, the bias power was set to 100 W, the mixed gas was introduced into the etching chamber at a flow rate of 50 mL / min, and plasma gas was generated as etching gas, and the amorphous carbon film was dry-etched using the plasma gas, and a groove pattern as the second opening was formed on the amorphous carbon film. In this way, dry etching of the carbon atom-containing film was completed.
[0100] At this time, the mixed gas was composed of a mixed gas of oxygen and sulfur dioxide, the etching time was 20 minutes, and the content of sulfur dioxide in the total volume of oxygen and sulfur dioxide was 30 volume % (the content of oxygen was 70 volume %).
[0101] After etching was completed, the cross-section of the amorphous carbon film was observed using SEM (product name "SU8230", manufactured by Hitachi High-Tech Corporation), and the etching depth L2 of the groove pattern formed in the amorphous carbon film was confirmed. The etching depth L2 was 1706 nm, and the etching rate Vc of the carbon film was 85 nm / min as shown in Table 1.
[0102] On the other hand, the depth of the opening removed by etching in the portion other than the groove in the mask (the portion with the mask design width W) was confirmed to be 179 nm, and the etching rate Vm of the mask was 8.7 nm / min.
[0103] Using the etching rate Vc of the carbon atom-containing film and the etching rate Vm of the mask obtained as described above, the carbon atom-containing film / mask selectivity ratio was obtained as the etching selectivity ratio according to the following formula (1). As a result, the etching selectivity ratio was 10.
[0104] Etching selectivity = Etching rate Vc of carbon-containing film ÷ Etching rate Vm of mask... (1)
[0105] [Comparative Example 1]
[0106] The dry etching of the amorphous carbon film was performed in the same manner as in Example 1 except that the mixed gas was set as shown in Table 1. Then, the etching rates of the carbon atom-containing film and the mask were calculated. The results are shown in Table 1. As shown in Table 1, the etching rate Vc of the carbon atom-containing film was 74 nm / min, the etching rate Vm of the mask was 11.4 nm / min, and the etching selectivity (Vc / Vm) was 6.
[0107] [Example 2]
[0108] The dry etching of the amorphous carbon film was performed in the same manner as in Example 1 except that the groove design width L1 of the mask and the mask design width W were set as shown in Table 2. Then, the etching rates of the carbon atom-containing film and the mask were calculated. The results are shown in Table 2. As shown in Table 2, the etching rate Vc of the carbon atom-containing film is 105 nm / min, the etching rate Vm of the mask is 7.4 nm / min, and the etching selectivity (Vc / Vm) is 14.
[0109] [Comparative Example 2]
[0110] The dry etching of the amorphous carbon film was performed in the same manner as in Example 2 except that the mixed gas was set as shown in Table 2. Then, the etching rates of the carbon atom-containing film and the mask were calculated. The results are shown in Table 2. As shown in Table 2, the etching rate Vc of the carbon atom-containing film was 88 nm / min, the etching rate Vm of the mask was 9.8 nm / min, and the etching selectivity (Vc / Vm) was 9.
[0111] [Example 3]
[0112] The dry etching of the amorphous carbon film was performed in the same manner as in Example 1 except that the groove design width L1 of the mask and the mask design width W were set as shown in Table 2. Then, the etching rates of the carbon atom-containing film and the mask were calculated. The results are shown in Table 3. As shown in Table 3, the etching rate Vc of the carbon atom-containing film is 116 nm / min, the etching rate Vm of the mask is 5.4 nm / min, and the etching selectivity (Vc / Vm) is 21.
[0113] [Comparative Example 3]
[0114] The dry etching of the amorphous carbon film was performed in the same manner as in Example 3 except that the mixed gas was set as shown in Table 3. Then, the etching rates of the carbon atom-containing film and the mask were calculated. The results are shown in Table 3. As shown in Table 3, the etching rate Vc of the carbon atom-containing film was 98 nm / min, the etching rate Vm of the mask was 6.5 nm / min, and the etching selectivity (Vc / Vm) was 15.
[0115] [Table 1]
[0116]
[0117] [Table 2]
[0118]
[0119] [Table 3]
[0120]
[0121] From Tables 1 to 3 and Figure 5 The results show that, when etching a carbon atom-containing film of a structure, the etching selectivity is larger when using a mixed gas containing sulfur dioxide than when using a mixed gas containing carbonyl sulfide, and the carbon atom-containing film etching selectivity is excellent.
[0122] Description of Reference Numerals
[0123] 1-etching chamber, 10-support body, 20-carbon atom-containing film, 21-second opening, 30-mask, 31-first opening, 100-structure, 200-structure, L1-groove design width (design width of the first opening), L2-depth of the second opening, W-mask design width (width of the physical part of the mask other than the first opening), G-mixed gas.
Claims
1. A dry etching method for a carbon-containing atom film, which uses an etching gas to etch the carbon-containing atom film containing carbon atoms, comprising: a mixed gas introducing step of introducing a mixed gas containing at least oxygen and sulfur dioxide into an etching chamber in which a structure is arranged, the structure including the carbon atom-containing film and a mask having a first opening; and an etching step of converting the mixed gas into plasma in the etching chamber to generate plasma gas, and using the plasma gas as the etching gas to etch the carbon atom-containing film of the structure to form a second opening, In the mixed gas introduction step, the mask includes an oxygen-containing material, and the width of the first opening of the mask is 10 to 150 nm.
2. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The width of the first opening of the mask is 40 to 150 nm.
3. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The first opening is in the shape of a groove or a hole.
4. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The carbon atom-containing film includes amorphous carbon.
5. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The oxygen-containing material contained in the mask is silicon dioxide.
6. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The carbon atom-containing film has a thickness of 0.1 μm or more.
7. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The carbon atom-containing film has a thickness of 10.0 μm or less.
8. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The thickness of the mask is greater than or equal to 0.01 times the thickness of the carbon atom-containing film.
9. The dry etching method of a carbon atom-containing film according to claim 1, wherein: The thickness of the mask is 0.5 times or less of the thickness of the carbon atom-containing film.
10. The dry etching method for a carbon atom-containing film according to any one of claims 1 to 9, wherein: In the mixed gas, the content of the sulfur dioxide in the total volume of the sulfur dioxide and the oxygen is 20 to 40 volume %.