JP4880495B2 - Deposition equipment - Google Patents

Description

In the present invention, when wiring is formed on a substrate, an overhang (overhung) of a hole or trench-shaped opening of a conductive coating film formed on the surface region of the substrate including the hole or trench or it relates formed MakuSo location to improve the asymmetry of the edge portion of the substrate.

  With recent miniaturization of semiconductor structures, various techniques have been used to improve the shape of the coating film. For example, as a technique for improving the shape and state of the substrate surface, the surface of the substrate of a semiconductor, ceramics or multilayer film is irradiated with accelerated ions so that the atoms constituting the substrate are ejected from the surface, that is, sputtered. An ion milling method for changing the shape of the surface or polishing the surface is known. The ions used in this ion milling method are generally inert gas argon, the incident angle of ions to the substrate surface is about several degrees to about 20 degrees, and the acceleration voltage is several kV. Select optimal thin film formation conditions for each substrate, such as changing the ion species and lowering the incident angle and acceleration voltage of ions to the substrate in order to suppress changes in composition and amorphization of the substrate surface layer due to ion irradiation. Has been implemented. This ion milling method is also used to remove an impurity layer on the surface of a thin film sample after chemical polishing or electrolytic polishing. Recently, an atom milling method using neutral atoms has also been used, and it is effectively used for preparing semiconductor samples such as silicon.

  As an example of this type of prior art, when a target is sputtered to form a thin film on the substrate surface, the substrate surface is laterally (angled from 0 ° to 30 ° with respect to the substrate surface, ie, 60 ° to 90 ° It is known that a thin film of wiring can be formed by irradiating an ion beam (within a range of incident angles) to remove the sputtered particles deposited on the opening edge of the fine groove formed on the substrate, that is, the trench. (See Patent Document 1).

  As another prior art, an interlayer insulating film is formed on a semiconductor substrate, a wiring groove is formed, Cu is deposited and embedded in the wiring groove, and a CMP (chemical mechanical polishing) method is used. A method of forming a Cu wiring in a wiring trench by removing a Cu conductive film on an interlayer insulating film, and a wiring penetrating the organic compound film by forming an organic compound film on the interlayer insulating film formed on a semiconductor substrate A trench is formed, a Cu wiring material is embedded in the wiring trench, a wiring layer is formed, the Cu wiring material on the organic compound film is removed by a CMP method or an RIE method, and the organic compound film is removed to form a Cu wiring. There is a known method (see Patent Document 2).

  Further, a mask corresponding to the Cu wiring to be formed is formed on the Cu layer formed on the substrate surface, and the Cu layer not covered with the mask is decomposed with iodine by decomposing reactive gas containing iodine with plasma. There is also known a method of forming Cu wiring by reacting with Cu to generate Culx and cleaning the generated Culx (see Patent Document 3 and Patent Document 4).

Japanese Patent Laid-Open No. 11-140640 Japanese Patent Laid-Open No. 2000-124218 Japanese Patent Application Laid-Open No. 2004-6441 Japanese Patent Laid-Open No. 2004-6443

  In a known technique for attracting ions to a substrate by applying RF or DC bias power to the substrate and improving the shape of the coating film to a desired shape, the bias potential of the substrate is up to about 150V.

A Ti film is formed as a lower layer on the substrate to a thickness of 10 nm, a Cu layer is formed thereon to a thickness of 45 nm, a sample having a 55-60 nm fine groove (trench), and a Ti film is formed on the substrate. A sample having a thickness of 30 nm and provided with a fine groove (trench) of 55 to 60 nm was prepared, and the shape change of the Ti layer and the Cu layer was observed for this sample using an ion milling method. In this case, the acceleration voltage is 200 eV, argon ions are used as irradiation ions, and the ion current density is 0.4 mA / cm ² . In the former sample, neither the shape of the overhang in the trench nor the opening width was changed. On the other hand, in the latter sample, etching of the opening edge of the trench proceeded with respect to the Ti layer, but an acute opening etching shape was not obtained. From this, low energy argon particles with an acceleration voltage of about 200 eV cannot change the shape and width of the overhang of the trench opening relative to the Cu coating film, and the Ti coating film cannot change the trench width. It was found that an acute opening etching shape of the opening could not be obtained.

  Further, as the demand for higher performance of semiconductor integrated circuits increases, device miniaturization advances and further miniaturization of wiring has been rapidly required. However, it has been pointed out that the conventionally proposed method and apparatus configuration cannot cope with the future fine structure.

  As described above, the methods and apparatuses according to the prior art proposed in each of the above-mentioned patent documents do not always cope with a fine structure higher than that of wiring that is currently required, but also a processing step. And the structure of the apparatus is complicated, there is a problem that it takes time to form wiring and the cost is increased. In particular, in the formation of wiring in semiconductor integrated circuits that are becoming increasingly miniaturized, how to improve overhang and asymmetry at the opening edge of via holes and trenches easily and at low cost when a coating film is formed by conventional sputtering. It is important to make it possible.

The present invention can cope with the miniaturization of the semiconductor structure, yet it is an object to provide a formed MakuSo location can improve overhangs and asymmetries in the opening of the via hole or a trench in the coating film formed on a substrate .

In order to achieve the above object, the present invention is a film forming apparatus configured to form a film in a recess on a substrate and irradiate the film with ions.
A processing chamber;
A substrate stage and a cathode electrode disposed in the processing chamber;
An ion source disposed at a position facing the substrate stage;
A gas inlet provided in a discharge vessel of the ion source;
A power source for accelerating ions to ion energy of 300 eV to 10000 eV,
The cathode electrode is disposed obliquely opposite to a substrate mounted on the substrate stage .

A film forming apparatus according to the present onset Ming, formed in a recess on the substrate, is configured to irradiate ions in the deposition, and the processing chamber, a substrate stage and a cathode electrode disposed in the processing chamber, An ion source disposed at a position facing the substrate stage; a gas inlet provided in a discharge container of the ion source; and a power source for accelerating ions to an ion energy of 300 eV to 10000 eV , wherein the cathode electrode is By being disposed obliquely opposite the substrate mounted on the substrate stage, it becomes possible to improve the overhang and asymmetric shape, and to configure the device as a single device. Therefore, a small and compact device can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a wiring forming system forming an embodiment of a film forming apparatus including an ion milling apparatus and a SIS (self ionized sputtering Self Ionized Sputtering) apparatus. The illustrated apparatus includes a transfer chamber 1, a carry-in chamber 2, Three SIS chambers 3, 4 and 5, three ion milling chambers 6, 7 and 8, and a carry-out chamber 9 are provided. The carry-in chamber 2, the SIS chambers 3, 4, 5 and the ion milling chambers 6, 7, 8 are each connected to the transfer chamber 1 through gate valves.

  As shown in FIG. 2, each of the SIS chambers 3, 4, and 5 includes a vacuum chamber 10, and the substrate 11 is opposed to the substrate 12 on which wiring for carrying the target 11 from the transfer chamber 1 is formed. Placed in position. The target 11 is a target including one or more of Cu, Al, Ti, Ta, W, Mn, Zr, Hf, V, Ag, Pd, Pt, Au, Mg, Co, and Ni, and is connected to the DC power source 13. Has been. On the back side of the target 11, a magnetron 14 is disposed outside the vacuum chamber 10 for efficient sputtering. The magnetron 14 includes a magnetic yoke member 16 that is rotated by a rotary driving device 15, and the magnetic yoke. And a magnet 17 supported by the member 16. The magnet 17 generates a magnetic field in the vacuum chamber 10 and traps electrons to increase the density of ions with respect to neutral atoms, thereby forming a high-density plasma region near the surface of the target 11.

  The vacuum chamber 10 is provided with a gas inlet 18 and connected to a gas supply source (not shown) via a flow rate adjusting valve 19. The gas supply source supplies oxygen and nitrogen gas into the vacuum chamber 10. . The vacuum chamber 10 is connected to an appropriate exhaust extinguishing system (not shown) via the exhaust port 20 so that the inside of the vacuum chamber 10 can have a desired degree of vacuum during operation of the apparatus. The substrate 12 is mounted on a substrate stage 21 and is electrically connected to a bias power source 22 to apply an RF or DC bias.

  Each ion milling chamber 6, 7, 8 comprises a vacuum chamber 30 as shown in FIG. 3, and a high-frequency discharge ion source 31 is carried into the vacuum chamber 30 from the transfer chamber 1. It is arranged at a position facing the substrate 12. The ion source 31 includes a discharge vessel 32 and a high frequency coil 33, and the high frequency coil 33 is connected to an RF power source 34. An exciting coil 35 is provided below the high frequency coil 33. Further, the ion source 31 includes an acceleration and extraction electrode 36, and these acceleration and extraction electrodes 36 are connected to a DC power source 37 that accelerates ions to an ion energy of 300 eV to 10000 eV. Argon or neon gas is supplied into the discharge vessel 32 of the ion source 31 through a gas inlet 38. Note that the angle α shown on the substrate 12 in FIG. 3 is an incident angle α when ions are incident on the surface of the substrate 12, and is set in the range of 0 ° to 30 ° in the present invention. .

  FIG. 4 shows another embodiment of a film forming apparatus including an ion milling apparatus and an SIS apparatus. In the illustrated apparatus, the ion milling apparatus and the SIS apparatus are provided in the same vacuum chamber 40. That is, in the vacuum chamber 40, the cathode electrode 41 constituting the SIS device and the target 42 mounted thereon are disposed obliquely facing the substrate 44 mounted on the substrate stage 43, and the cathode electrode 41 is a DC power source. 45 to bias the target 42 during operation. The substrate 44 is mounted on the substrate stage 43 and is connected to a bias power source 46 so that an RF or DC bias is applied. The target 42 is Cu, Al, Ti, Ta, W, Mn, Zr, Hf, V, Ag, Pd, Pt, Au, Mg, Co, as exemplified with respect to the embodiment shown in FIGS. It is a target containing one type of Ni.

  In the vacuum chamber 40, an ion source 47 constituting an ion milling device is disposed to face the substrate 44 mounted on the substrate stage 43, and is set in a range of 0 ° to 30 ° with respect to the surface of the substrate 44. The ions can be irradiated at an incident angle α. The ion source 47 includes a discharge vessel 48 and a high frequency coil 49, and the high frequency coil 49 is connected to an RF power source 50. An exciting coil 51 is provided below the high frequency coil 49. Further, the ion source 47 includes an acceleration and extraction electrode 52, and these acceleration and extraction electrodes 52 are connected to a DC power source 53 that accelerates ions to ion energy of 300 eV to 10000 eV. The discharge vessel 48 of the ion source 47 is also configured to supply argon or neon gas via the gas inlet 54. In FIG. 4, reference numeral 55 denotes a gas introduction port for introducing oxygen and nitrogen gas into the vacuum chamber 40.

  An experimental example in which the shape change in the Cu / Ti coating layer is performed using the illustrated apparatus configured as described above will be described.

FIG. 5 shows a sample in which a Ti layer is formed as a lower layer on a substrate to a thickness of 10 nm, a Cu layer is formed thereon to a thickness of 150 nm, and a trench having a hole diameter of 0.2 μm and an aspect ratio of about 2 is provided. Shows changes in the shape of the film after elapse of time, 0 seconds, 15 seconds, 30 seconds, and 45 seconds after setting the ion acceleration voltage to 300 eV and the ion current of 50 mA. An improvement in asymmetry at the bottom of the trench was observed.

  FIG. 6 shows a sample in which a Ti layer is formed as a lower layer on a substrate to a thickness of 10 nm, a Cu layer is formed thereon to a thickness of 150 nm, and a via hole having a hole diameter of 0.2 μm and an aspect ratio of about 2 is provided. Shows the change in the shape of the film over time, 0 seconds, 8 seconds, 15 seconds and 30 seconds after setting the ion acceleration voltage to 1000 eV and the ion current to 50 mA. In this example, improvement in asymmetry and shape of the opening was observed at the appropriate irradiation time.

  In FIG. 7, as in the case of FIG. 5, a Ti layer is formed as a lower layer on the substrate to a thickness of 10 nm, a Cu layer is formed thereon to a thickness of 150 nm, a pore diameter of 0.2 μm, and an aspect ratio of about For the sample with 2 via holes, the change in film shape is shown after the passage of time, 0 seconds, 15 seconds, 30 seconds, and 60 seconds after setting the ion acceleration voltage to 2000 eV and the ion current to 50 mA. In this example, a significant improvement in asymmetry and the shape of the opening was observed.

  In FIG. 8, a sample prepared under the same conditions as in FIG. 7 was set to an ion acceleration voltage of 2000 eV and an ion current of 50 mA, and the sample was irradiated with ions at an incident angle α = 30 degrees for 30 seconds. Shows the results of the hour.

  In FIG. 9, as in the case of FIG. 5, a Ti layer is formed as a lower layer on the substrate to a thickness of 10 nm, a Cu layer is formed thereon to a thickness of 150 nm, a pore diameter of 0.2 μm, and an aspect ratio of about For the sample with 2 via holes, the change in the shape of the film is shown over time, 20 seconds, 40 seconds, 60 seconds, and 90 seconds after setting an ion acceleration voltage of 3000 eV and an ion current of 50 mA. In this example, asymmetry and a significant improvement in the shape of the opening are observed and the bottom coverage is maintained.

  FIG. 10 shows the correlation between various ion energies and irradiation times and coverage. From this figure, it is recognized that when the ion energy is increased, the shape of the opening is improved and the etching inside the via hole is small.

  From the above experimental examples, the overhang cannot be removed when the ion energy of the ions to be irradiated is 200 eV or less, whereas the overhang can be removed when the ion energy is 10,000 eV or more, but surface roughness occurs in the irradiated film. Therefore, in the present invention, by selecting the ion energy of the ions to be irradiated in the range of 300 eV to 10000 eV, the overhang and the asymmetry of the edge in the recesses such as trenches, via holes or contact holes formed on the substrate are sufficient. It was confirmed that it can be improved.

  In the embodiment shown in FIGS. 1 to 3, the same number of SIS chambers and ion milling chambers are provided, but they are not necessarily the same number, and can be arbitrarily set as necessary.

Schematic which shows one Embodiment of this invention of the film-forming apparatus containing an ion milling apparatus and a SIS (self ionization sputtering Self Ionized Sputtering) apparatus. Schematic which shows the structural example of the SIS apparatus in FIG. Schematic which shows the structural example of the ion milling apparatus in FIG. Schematic which shows another embodiment of this invention of the film-forming apparatus containing an ion milling apparatus and a SIS apparatus. Sectional drawing which shows the experiment example implemented using the illustrated apparatus. The other experiment example implemented using the illustrated apparatus is shown, (a) is a top view, (b) is sectional drawing. The other experiment example implemented using the illustrated apparatus is shown, (a) is a top view, (b) is sectional drawing. The other experiment example implemented using the illustrated apparatus is shown, (a) is a top view, (b) is sectional drawing. The other experiment example implemented using the illustrated apparatus is shown, (a) is a top view, (b) is sectional drawing. Sectional drawing which shows another experiment example implemented using the illustrated apparatus.

Explanation of symbols

1: Transfer chamber 2: Loading chamber 3, 4, 5: SIS chamber 6, 7, 8: Ion milling chamber 10: Vacuum chamber 11: Target 12: Substrate on which wiring is to be formed 13: DC power supply 14: Magnetron 15: Rotation Drive device 16: Magnetic yoke member 17: Magnet 18: Gas inlet 19: Flow rate adjusting valve 20: Exhaust port 21: Substrate stage 22: Bias power source 30: Vacuum chamber 31: Ion source 32: Discharge vessel 33: High frequency coil 34: RF power source 35: exciting coil 36: acceleration and extraction electrode 37: DC power source 38: gas inlet 40: vacuum chamber 41: cathode electrode 42: target 43: substrate stage 44: substrate 45: DC power source 46: power source 47: ion source 48: Discharge vessel 49: High frequency coil 50: RF power source 51: Excitation coil 52: Acceleration and extraction electrode 53: DC power source 5 : Gas inlet port 55: gas inlet

Claims (1)

A film forming apparatus configured to form a film in a recess on a substrate and irradiate the film with ions;
A processing chamber;
A substrate stage and a cathode electrode disposed in the processing chamber;
An ion source disposed at a position facing the substrate stage;
A gas inlet provided in a discharge vessel of the ion source;
A power source for accelerating ions to ion energy of 300 eV to 10000 eV,
The film forming apparatus, wherein the cathode electrode is disposed obliquely opposite to a substrate mounted on the substrate stage .