JP2005223360A - Manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability, while taking into consideration the correspondence to speed enhancement, in a semiconductor device having an insulating layer composed of fluorine added carbon. <P>SOLUTION: A wiring layer 102, in which an element is formed on a semiconductor substrate is formed, and on the wiring layer 102, a fluorine added carbon film 103 is formed. Then, on the fluorine added carbon film 103, a hard mask 105 made of SiCN is formed. The hard mask 105 is formed by chemical vapor deposition method, with a gas containing hydrogen such as SiH<SB>4</SB>and C<SB>2</SB>H<SB>4</SB>, and gas containing nitrogen such as N<SB>2</SB>as a source gas. Thereafter, the fluorine added carbon film 103 is selectively etched with the hard mask 105 selectively etched as a mask, to form a new wiring layer 104 on the hard mask 105. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a semiconductor device using a layer made of fluorine-added carbon as an insulating layer.

  In order to increase the integration density of semiconductor integrated circuits, patterns such as wiring and the like are being miniaturized and circuits are being multilayered. One of them is a multilayer wiring technique in which wirings are configured in multiple layers. In this multilayer wiring technology, the upper and lower wiring layers are connected by a conductive portion arranged in a predetermined region, and an interlayer insulating film made of an insulator is arranged and separated between regions other than the conductive portion. ing.

A typical material used for the interlayer insulating film is silicon oxide (SiO ₂ ). In recent years, in order to further increase the operation speed of the integrated circuit, the relative dielectric constant of the interlayer insulating film may be lowered. It is requested. That is, SiO ₂ has a relative dielectric constant of about ε = 4, and development of a material having a relative dielectric constant smaller than this is actively made.

As a material having a relative dielectric constant smaller than that of SiO ₂ , for example, there is a fluorine-added carbon film made of carbon and fluorine. This fluorine-added carbon film can be formed by, for example, a plasma film forming process using electron cyclotron resonance (ECR).

  This film forming method will be described. First, in the film forming apparatus shown in FIG. 8, a microwave of 2.45 GHz is supplied into the plasma generation chamber 801a from the high frequency power supply unit 802 through the waveguide 802a. At the same time, a magnetic field of 875 Gauss is applied by the magnetic field coils 803 and 803a, and the Ar gas introduced from the introduction tube 804 is turned into a high density plasma by electron cyclotron resonance.

On the other hand, C ₄ F ₈ gas and C ₂ H ₄ gas are introduced into the film formation chamber 801b from the gas supply unit 805 through the gas introduction pipes 805a and 805b, and these are activated by the above-described high-density plasma and activated. Form a seed. Then, the activated species forms a high-hardness fluorine-added carbon film 808 with good adhesion on the surface of the wafer 807 on the mounting table 806 disposed in the film formation chamber 801b. Note that the wafer 807 is fixed by an electrostatic chuck 806 a of the mounting table 806. Further, the inside of the film forming chamber 801b is evacuated to a predetermined degree of vacuum by a vacuum evacuation unit (not shown) communicating with this through an exhaust pipe 810.

  As described above, a fluorine-added carbon film can be formed. However, in order to use this fluorine-added carbon film as an interlayer insulating film, for example, fine processing such as forming a hole portion in which a connection portion for connecting upper and lower wiring layers is required is required.

Here, the microfabrication of the fluorine-added carbon film will be described. First, as shown in FIG. 9A, the fluorine-added carbon film 902 is formed on the lower wiring layer 901 serving as a base as described above. Then, an inorganic film 903 made of SiO ₂ is formed on the fluorine-added carbon film 902. Next, as shown in FIG. 9B, a resist pattern 904 having an opening 904a at a predetermined location is formed on the inorganic film 903 by a known photolithography technique.

Next, the inorganic film 903 is selectively etched using the resist pattern 904 as a mask. As a result, as shown in FIG. 9C, a hard mask 905 having an opening 905a at a position corresponding to the opening 904a is formed. Here, in this etching, for example, dry etching using plasma of CF ₄ may be used.

  Next, the fluorine-added carbon film 902 is selectively etched using the hard mask 905 as a mask. As a result, a hole 906 is formed in the fluorine-added carbon film 902 as shown in FIG. Here, in this etching, for example, dry etching using oxygen gas plasma may be used. If oxygen gas is used, a large etching selection ratio (ratio between both etching rates) can be obtained between the fluorine-added carbon film 902 and the hard mask 905. If oxygen gas plasma is used, the resist pattern 904 can also be removed by etching at the same time.

  Here, the microfabrication of the fluorine-added carbon film using a hard mask will be described.

  In microfabrication, a resist pattern formed by a photolithography technique is generally selectively etched using a mask. At this time, the resist pattern needs to be resistant to etching as a mask for the layer to be processed under the resist pattern. When the layer to be processed is thick, resist pattern etching resistance is particularly necessary. This resist pattern is formed, for example, by exposing and developing a photosensitive photoresist and made of an organic material.

  However, when an organic film such as the above-described fluorine-added carbon film is finely processed, dry etching using oxygen plasma is used. In this case, if a resist pattern, which is an organic film, is used as a mask, it is also etched, so that selective etching cannot be performed.

In contrast, when a fluorine-added carbon film is etched with oxygen gas plasma, if a master pattern made of an inorganic material such as SiO ₂ is used, this is hardly etched with oxygen plasma, so that selective etching is possible. It becomes. For this reason, as described above, a hard mask made of SiO ₂ or the like is used in the fine processing of the fluorine-added carbon film.

By the way, in order to form this hard mask, an inorganic film such as SiO ₂ is processed. For this processing, dry etching using plasma of CF ₄ or C ₄ F ₈ may be used. In this case, since the resist pattern which is an organic film is hardly etched, the hard mask can be formed by selective etching using the resist pattern as a mask as described above.

However, when a hard mask made of SiO ₂ or silicon nitride (SiN), which is generally used for processing an organic film, is used for fine processing of a fluorinated carbon film, there are the following problems. The reliability of a semiconductor device using a carbon film as an interlayer film has been reduced.

First, since SiO ₂ and SiN have low adhesion to a fluorine-added carbon film that is an organic film containing fluorine, there is a problem that the hard mask is easily peeled off. As described above, since the insulating material is used as the hard mask, the hard mask is also used as a part of the interlayer insulating film. However, after microfabrication of a fluorine-added carbon film as an interlayer insulating film, when a stress is applied in a later process, such as when a metal film for a wiring electrode is formed on them, the hard mask becomes a fluorine-added carbon. It may come off from the film. Further, if a metal film for the wiring electrode is formed and then flattened by a chemical mechanical polishing method, a large stress is applied, so that the hard mask is almost surely peeled off from the fluorine-added carbon film.

Next, when a hard mask made of SiO ₂ or SiN is used for fine processing of the fluorine-added carbon film, there is a problem that the etching selectivity is reduced as follows. Fine processing of the fluorine-added carbon film uses dry etching using oxygen gas plasma as described above. Considering only this point, if a hard mask is made of SiO ₂ or SiN, a large selection ratio should be obtained.

However, when the fluorine-added carbon film is etched by plasma of oxygen gas, F (fluorine) and C (carbon) are generated in the atmosphere due to the decomposition of the fluorine-added carbon film, and these active species are generated by the plasma. Will occur. As a result, since SiO ₂ and SiN are etched by the active species, the conventional hard mask has a problem that when etching is performed simultaneously with the fluorine-added carbon film, the selectivity is lowered and the processing accuracy is deteriorated.

  At the same time, from the viewpoint of speeding up the semiconductor device, as in the case of the insulating layer using the fluorine-added carbon film, the insulating layer used as the hard mask is required to use a material having a low relative dielectric constant as much as possible. ing.

  The present invention has been made to solve the above problems. That is, the present invention provides a method for manufacturing a semiconductor device that can improve reliability in a semiconductor device provided with an insulating layer made of fluorine-added carbon while taking measures for high speed into consideration. Objective.

In order to achieve this object, the present invention provides:
Forming a wiring layer on the semiconductor substrate on which the element is formed;
Forming a first insulating layer made of fluorine-added carbon on the wiring layer;
A second insulating layer made of silicon, carbon, and nitrogen is formed on the first insulating layer by chemical vapor deposition using SiH ₄ , a gas containing carbon, and a gas containing nitrogen as a source gas. Process,
Selectively etching the second insulating layer until the surface of the first insulating layer is partially exposed;
Selectively etching the first insulating layer using the selectively etched second insulating layer as a mask;
And a step of forming a new wiring layer on the second insulating layer after selectively etching the first insulating layer. A method of manufacturing a semiconductor device is provided. .

  With this configuration, a semiconductor device having a structure in which the first insulating layer made of fluorine-added carbon is in contact with the second insulating layer made of silicon, carbon, and nitrogen is obtained between the wiring layers. As a result, the adhesion between the first insulating layer and the second insulating layer is improved as compared with the conventional case, and peeling is suppressed. In addition, the second insulating layer made of silicon, carbon, and nitrogen can have a higher etching selectivity than the conventional one, and has a dielectric constant that is higher than that made of silicon and nitrogen or silicon and carbon. Can be reduced. For this reason, in the semiconductor device, it is possible to improve the reliability while considering the correspondence to the high speed.

  In this manufacturing method, it is preferable to further include a step of adding boron to the second insulating layer from the viewpoint of lowering the relative dielectric constant of the second insulating layer.

  The step of selectively etching the second insulating layer may be performed using plasma of a compound gas containing carbon and fluorine or plasma of a compound gas containing carbon and hydrogen.

  In addition, the step of selectively etching the first insulating layer is performed by using plasma of a gas containing oxygen, whereby the second insulating layer and the wiring layer are hardly etched.

  In addition, the step of selectively etching the first insulating layer is performed by using plasma of a gas containing hydrogen, so that etching by reactive ions becomes dominant, and etching with higher anisotropy is performed. Can be done.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
First, a method for manufacturing a semiconductor device as the first embodiment of the present invention will be described. In this embodiment, the semiconductor device is configured as shown in FIG. 1a. This configuration will be described. First, an insulating film 101, for example, a SiO ₂ film is formed so as to cover an element (not shown) such as a MOS transistor formed on a semiconductor substrate made of silicon (Si). A wiring layer (not shown) made of, for example, W, which is electrically connected to this element, and a wiring layer 102 made of, for example, copper (Cu), connected thereto, are formed.

Further, a fluorine-added carbon film 103 as a first insulating layer is formed on the SiO ₂ film 101 so as to cover the Cu layer 102. In the fluorine-added carbon film 103, a groove 104a and a hole 104b are formed. A wiring layer 104 made of Cu, for example, is formed in the groove 104a and the hole 104b, and this is electrically connected to the Cu layer 102 described above. Here, an adhesion layer 104 c is formed on a contact surface between the fluorine-added carbon film 103 and the Cu layer 102 and the Cu layer 104.

  The adhesion layer 104c includes, for example, a TiN layer 104c ′ and a Ti layer 104c ″ as shown in FIG. 1b in order to improve adhesion between the Cu layer 104 and the fluorine-added carbon film 103. The adhesion layer 104c is not limited to such a laminated structure of TiN / Ti, and a laminated structure of refractory metal nitride / refractory metal such as TaN / Ta or WN / W may be used. Is possible.

  In the first embodiment, a hard mask 105 made of SiCN as a second insulating layer is formed on the fluorine-added carbon film 103 to a thickness of about 100 nm. This SiCN does not necessarily mean that it has a chemical composition / chemical bond, but at least Si, C, and N are used as components.

  Further, on the hard mask 105, a fluorine-added carbon film 106 as a first insulating layer, a Cu layer 107 embedded in the groove 107a and the hole 107b, an adhesion layer 107c, A hard mask 108 made of SiCN is formed. That is, the hard mask 108 made of SiCN is also formed on the fluorine-added carbon film 106 to a thickness of about 100 nm. Since the Cu layer 104 and the Cu layer 107 are made of the same material, it is not necessary to form a barrier film or the like at the contact interface.

As described above, in the first embodiment, the hard masks 105 and 108 made of SiCN are provided on the interlayer insulating films 103 and 106 made of the fluorine-added carbon film. As a result, for example, since there is a hard mask 105 made of SiCN between the fluorine-added carbon film 103 and the fluorine-added carbon film 106, compared to the conventional case where SiO ₂ or the like is used for the hard mask, The adhesion between these layers can be improved.

  Note that a semiconductor device may be provided by providing a similar stacked structure over the hard mask 108 and the Cu layer 107. That is, a semiconductor device having a structure in which a similar stacked structure is repeatedly stacked by an arbitrary number of stages may be used.

  Next, a method for manufacturing the above-described wiring structure will be described. In the following description, the Cu layer 104 and the hard mask 105 shown in FIG. 1 are already formed.

First, as shown in FIG. 2a, a fluorine-added carbon film 206 is formed to a thickness of about 700 nm on the hard mask 105 made of the Cu layer 104 and SiCN. As described above, the fluorine-added carbon film 206 is formed by a plasma film forming process using C ₄ F ₈ gas and C ₂ H ₄ gas as source gases using electron cyclotron resonance (ECR).

Next, as shown in FIG. 2B, first, an insulating film 208 made of SiCN is formed on the fluorine-added carbon film 206. This may be performed, for example, by chemical vapor deposition (CVD) using SiH ₄ , C ₂ H ₄ , and N ₂ as source gases. Further, a resist pattern 211 having a hole portion 211a is formed on the insulating film 208 at a predetermined location. The resist pattern 211 may be formed using a known photolithography technique.

Next, the insulating film 208 is etched using the resist pattern 211 as a mask to form a hard mask 108 provided with a hole 208a as shown in FIG. 2c. For this etching, for example, dry etching using plasma of C ₄ F ₈ may be used.

  Next, using the hard mask 108 provided with the hole 208a as a mask, the underlying fluorine-added carbon film 206 is etched. For this etching, reactive ion etching using oxygen gas plasma may be used. As described above, since the hard mask 108 is made of SiCN, it is hardly etched by plasma of oxygen gas. On the other hand, the fluorine-added carbon film 206 is etched (ashed) by plasma of oxygen gas. As a result, as shown in FIG. 2d, hole portions 206a can be formed in the fluorine-added carbon film 206 by this etching process. At this time, since the plasma of oxygen gas is used, the resist pattern 211 which is an organic film is also removed at the same time.

Here, the selection ratio in dry etching using oxygen gas plasma for a hard mask made of a fluorine-added carbon film and SiCN will be described. The etching rate (nm / min) when each hard mask material such as SiO ₂ or SiN is dry-etched together with the fluorine-added carbon film using oxygen gas plasma is shown below.

Fluorine-added carbon film ... 1538
SiN ... 37
SiC ... 45
SiO ₂ ... 42
SiCN ... 15
As described above, when processing is performed at the same time as the fluorine-added carbon film, SiCN has a much lower etching rate by oxygen gas plasma than other hard mask materials. Therefore, if SiCN is used for the hard mask as in the first embodiment, a large selectivity can be obtained in the etching of the fluorine-added carbon film, so that the processing accuracy can be further improved.

  Next, as shown in FIG. 2E, a resist pattern 212 having a groove 212a is formed on the hard mask 108. Next, as shown in FIG. The resist pattern 212 may be formed using a known photolithography technique. Here, the groove 212a is formed so that a part thereof overlaps with the hole 206a.

Then, the hard mask 208 is etched using the resist pattern 212 as a mask, so that the groove 108 a is formed in the hard mask 108. For this etching, for example, dry etching using C ₄ F ₈ plasma may be used. In this dry etching using C ₄ F ₈ plasma, the fluorine-added carbon film 206 is hardly etched, so that the hard mask 108 can be selectively etched.

  Next, the fluorine-added carbon film 206 is etched using the hard mask 108 in which the groove 108a is formed as a mask to form a fluorine-added carbon film 106 in which the groove 107a is formed to a depth of about 400 nm as shown in FIG. 2f. To do. Again, reactive ion etching using oxygen gas plasma may be used. Since the plasma of oxygen gas is used, the resist pattern 212 on the hard mask 108 is also removed at the same time. Then, the through hole 107 b formed by the hole portion 206 a formed in the fluorine-added carbon film 206 is placed in the groove 107 a formation region of the fluorine-added carbon film 106.

  Next, as shown in FIG. 2g, first, a thin metal film 207a, which is an adhesion layer composed of a TiN layer and a Ti layer, is formed so as to cover the hard mask 108, the through holes 107b, and the grooves 107a and 108a. . Then, a metal film 207 made of copper is formed on the hard mask 108 so as to fill the through holes 107b and the groove portions 107a and 108a via the metal film 207a. The metal film 207 may be formed by a well-known metal film forming method such as electroless plating or sputtering.

  Then, the metal films 207 and 207a are polished from the surface by chemical mechanical polishing (CMP). As a result, as shown in FIG. 2h, when the surface of the hard mask 108 is exposed, a Cu layer 107 is disposed on the Cu layer 104 via the fluorine-added carbon film 106, and the fluorine-added carbon film 106 and Cu A state in which the layer 107 is in contact with the adhesive layer 107c having a TiN / Ti structure is obtained. Needless to say, the formation from the fluorine-added carbon film 103 to the Cu layer 104 omitted in the above can be performed in substantially the same manner as described above.

Here, in the case where SiCN is used as the hard mask material as described above and in the case where SiO ₂ is used as in the conventional case, the adhesion between the formed hard mask and the fluorine-added carbon film laminated therewith Compared. In this case, the adhesion strength in the three-layer structure of “fluorine-added carbon film / hard mask / fluorine-added carbon film” was compared. For reference, the case where SiN was used as a hard mask material was also examined.

  The adhesion is measured as follows. First, as shown in FIG. 3, a sample in which a fluorine-added carbon film 602, a hard mask 603, and a fluorine-added carbon film 604 are sequentially laminated on a substrate 601 is prepared, and a predetermined adhesive is formed on the fluorine-added carbon film 604. The test bar 605 is fixed by the above. Then, with the substrate 601 fixed, a load in a direction away from the substrate 601 is applied to the test bar 605. And the load (Kpsi) when either film | membrane peels is made into adhesive force.

  The measurement result of the adhesion force described above is shown in FIG. As is apparent from FIG. 4, the use of SiCN as the hard mask material significantly improves the adhesion with the fluorine-added carbon film. As described above, if an adhesion force of 5 Kpsi or more is obtained between the fluorine-added carbon film, the hard mask portion is formed by chemical mechanical polishing at the time of electrode formation even if the hard mask is left as a part of the interlayer film. Peeling is suppressed.

Further, the graph of FIG. 5 shows the results of examining the difference in adhesion between the base film and the hard mask made of SiCN for three types of base films A, B, and C. In this case, the underlying film A is the above fluorine-containing carbon film, the base film B is "SiCO (H) film ((H) is H in _C x _{H y} group)", the base film C is SOD (Spin On Dilectric) It is a membrane. Moreover, the measuring method of contact | adhesion power is the same as the above. The SiCO (H) film uses, for example, methylsilane or alkoxysilane represented by SiH _x (CH ₃ ) _y as a raw material alone or an oxygen-based gas (O ₂ , N ₂ O, etc.), It is formed by a plasma CVD method. In this case, for example, SiLK, which is an organic polymer, is used as the SOD film.

Here, as described above, the hard mask is used as a part of the interlayer insulating film between the wiring layers. Therefore, even if the thickness of the hard mask is thinner than that of the fluorine-added carbon film, the dielectric constant is preferably as low as possible. Therefore, as shown in the graph of FIG. 6, when comparing the relative dielectric constant ε of various hard mask materials, SiCN used in this embodiment is about ε = 5.5, which is higher than SiO _{2 of} about ε = 4. However, it is considerably lower than SiN or SiC around ε = 8.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment, for the reasons described above, boron (B) is added to a hard mask made of SiCN from the viewpoint of further reducing the dielectric constant of the hard mask material. As described above, the relative dielectric constant of SiCN itself is about ε = 5.5, but when boron is added to this SiCN, the dielectric constant can be lowered to about ε = 5.1. Other configurations are the same as those in the first embodiment.

The addition of boron uses, for example, BF ₃ in addition to SiH ₄ , C ₂ H ₄ , and N ₂ as a source gas in the chemical vapor deposition method when forming the insulating film 208 made of SiCN shown in FIG. 2B, for example. What should I do? Further, SiH ₄ , C ₂ H ₄ , BF ₃ , SiH ₄ , BF ₃ , N ₂ may be used as a combination of source gases. Further, B ₂ F ₆ may be used instead of BF ₃ . By doing so, the formed insulating film is composed of SiCN, SiC, or SiN (SiBCN, SiBC, or SiBN) to which boron is added.

  Note that the addition of boron may be performed by ion implantation with respect to the already formed insulating film.

  Here, the result of investigating the change in the relative permittivity when boron is added to SiN, SiC and SiCN is shown in the graph of FIG. As shown in FIG. 7, the relative dielectric constants ε of SiN, SiC, and SiCN are about ε = 8.2, 7.9, and 5.5, respectively, while SiBN, SiBC with boron added thereto. And the relative dielectric constant ε of SiBCN is reduced to about ε = 5.9, 5.5, and 5.1, respectively.

[Other Embodiments]
In the above embodiment, the hard mask made of SiCN is formed by a manufacturing method using “SiH ₄ + C ₂ H ₄ + N ₂ ” as a source gas. However, the hard mask is formed by a manufacturing method using another source gas. It may be.

Here, the results of investigating the difference in relative permittivity when the hard mask made of SiCN is formed by different manufacturing methods (raw material gases) in three manufacturing methods (raw material gases) of A, B, and C are shown in FIG. Shown in the graph. In this case, the manufacturing method A uses “SiH ₄ + (carbon-containing source gas) + (nitrogen-containing source gas)” as the source gas, as in the above-described manufacturing method. Production methods B and C use a raw material gas in which SiH ₄ in production method A is replaced with SiH _x (CH ₃ ) _y and alkoxysilane (Silicon alkoxides), respectively.

As the source gas containing carbon, CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₂ H ₂ or the like can be used in addition to the above C ₂ H ₄ . In addition to the above N ₂ , for example, NF ₃ , N ₂ O, NO ₂ , N ₂ O ₄ , NO, NH _8, etc. can be used as the source gas containing nitrogen.

  As shown in FIG. 8, the manufacturing method A used in the present embodiment has a relative dielectric constant of about ε = 5.5, but the manufacturing method B and manufacturing method C have ε = 4.2-4. It has fallen to about 3. That is, according to the manufacturing method B or the manufacturing method C described above, the relative dielectric constant can be further reduced as compared with the case where boron is added as in the second embodiment.

In the above embodiment, oxygen gas plasma is used for etching the fluorine-added carbon film, but plasma of a mixed gas of hydrogen gas, argon gas, or nitrogen gas may be used. In this case, for example, the flow rate ratio of argon gas to mixed gas (Ar / (N ₂ + H ₂ + Ar)) may be substantially about 0.7 to 0.8. Further the flow rate ratio of the hydrogen gas and nitrogen gas _{(H 2 / (N 2 +} H 2)), it may be substantially 0.2 to 0.9. The degree of vacuum of the atmosphere for generating plasma may be about 5 to 15 mTorr.

  Even in this case, as shown below, as in the case of using oxygen gas, the etching rate (nm / min) when processed simultaneously with the fluorine-added carbon film is higher in SiCN than in other hard mask materials. And very small.

Fluorine-added carbon film ... 1826
SiN ... 58
SiC ... 88
SiO ₂ ... 95
SiCN ... 18
Here, the characteristics when hydrogen gas is used for etching as described above will be described. When reactive ion etching using plasma of mixed gas of hydrogen gas, argon gas and nitrogen gas is used, etching with higher anisotropy is possible than when oxygen gas is used when etching a fluorine-added carbon film It becomes.

  In dry etching, it is considered that reactive ions and radicals are generated as etching active species by generating plasma. Among these, in reactive ion etching in which reactive ions mainly fly to an object to be etched using an electric field, processing is performed in a state with high vertical anisotropy.

  However, since plasma is generated in the atmosphere, any radical that is not attracted by the electric field reaches the etching target and participates in the etching reaction. Then, if an etching reaction due to the radicals occurs, for example, side etching that etches to the lower part of the master pattern occurs. In such a mechanism, in the reactive ion etching method using oxygen gas plasma, oxygen radicals are highly reactive with organic compounds, so this oxygen radical is involved more than necessary in the etching reaction, The controllability of the etching shape of the fluorine-added carbon film is lowered.

  On the other hand, when the above-described mixed gas of hydrogen gas and argon gas or nitrogen gas is used, the etching active species for the fluorine-added carbon film are mainly hydrogen reactive ions and radicals. However, hydrogen radicals are not very reactive with organic compounds. For this reason, in the case of reactive ion etching using such a mixed gas, the etching active species for the fluorine-added carbon film is substantially only reactive ions of hydrogen. That is, in this case, etching hardly progresses depending on radicals having no directionality.

  As a result, when a mixed gas of hydrogen gas and argon gas or nitrogen gas is used, higher anisotropy is obtained and side etching is suppressed, so that processing accuracy such as dimensional controllability is improved. Can do.

  By the way, in the above-described embodiment, the groove is formed in the interlayer film made of the fluorine-added carbon film and the wiring layer is embedded therein. However, the present invention is not limited to this. For example, you may comprise as shown in FIG. This configuration will be described. First, a hard mask 702 made of SiCN is formed on an interlayer insulating film 701 made of a fluorine-added carbon film, and a wiring layer 703 is formed thereon. The wiring layer 703 is connected to a lower wiring layer (not shown) through through holes formed in the interlayer insulating film 701 and the hard mask 702.

  An interlayer insulating film 704 made of a fluorine-added carbon film is formed on the hard mask 702 so as to cover the wiring layer 703. A hard mask 705 made of SiCN is formed on the interlayer insulating film 704, and a wiring layer 706 is formed thereon. In addition, the wiring layer 706 is connected to the lower wiring layer 703 through through holes formed in the interlayer insulating film 704 and the hard mask 705.

  In this case, the hard masks 702 and 705 are used to form through holes for connecting the wiring layers. Therefore, in this case, for example, the hard mask 705 and the interlayer insulating film 704 are finely processed once. However, for example, the wiring layer 706 is formed by forming a metal film on the hard mask 705 and finely processing the metal film by a known photolithography technique and etching technique.

  In the above-described embodiment, Cu is used for the wiring layer. However, the present invention is not limited to this, and the same applies when aluminum (Al) or another conductive material is used.

The fragmentary longitudinal cross-section which showed the structure of the semiconductor device by the manufacturing method as embodiment of this invention. The figure which expands and shows a part of structure shown in FIG. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal section showing the manufacturing method of the semiconductor device as an embodiment of the present invention in order of a process. The typical longitudinal cross-sectional view for demonstrating the measuring method of adhesive force. The graph which shows the difference in the adhesive force by hard mask material. The graph which shows the difference in the adhesive force by the base film with respect to a hard mask. The graph which shows the difference in the dielectric constant by hard mask material. The graph which shows the difference in the dielectric constant of the hard mask material containing boron. The graph which shows the difference in the dielectric constant of the hard mask by a manufacturing method. The fragmentary longitudinal cross-section which showed the structure of the semiconductor device by the manufacturing method as other embodiment of this invention. The schematic longitudinal cross-sectional view which shows the structure of the plasma film-forming processing apparatus for forming a fluorine addition carbon film. Schematic longitudinal cross-sectional view which showed the manufacturing method of the conventional semiconductor device in order of the process of (a)-(d).

Explanation of symbols

102, 104, 107 Cu layer (wiring layer)
103, 106 Fluorine-added carbon film (first insulating layer)
105, 108 hard mask (second insulating layer)

Claims (5)

Forming a wiring layer on the semiconductor substrate on which the element is formed;
Forming a first insulating layer made of fluorine-added carbon on the wiring layer;
On the first insulating layer, a second insulating layer made of silicon, carbon, and nitrogen is formed by chemical vapor deposition using SiH ₄ , a gas containing carbon, and a gas containing nitrogen as a source gas. Process,
Selectively etching the second insulating layer until the surface of the first insulating layer is partially exposed;
Selectively etching the first insulating layer using the selectively etched second insulating layer as a mask;
And a step of selectively etching the first insulating layer and then forming a new wiring layer on the second insulating layer.   2. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of adding boron to the second insulating layer.   3. The method of manufacturing a semiconductor device according to claim 1, wherein the step of selectively etching the second insulating layer is performed using plasma of a gas containing a compound containing carbon and fluorine.   3. The method of manufacturing a semiconductor device according to claim 1, wherein the step of selectively etching the first insulating layer is performed using plasma of a gas containing oxygen.   3. The method of manufacturing a semiconductor device according to claim 1, wherein the step of selectively etching the first insulating layer is performed using plasma of a gas containing hydrogen.

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