Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/4401—Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber
  • C23C16/4404—Coatings or surface treatment on the inside of the reaction chamber or on parts thereof

Definitions

• the present invention relates to a film forming apparatus for performing a film forming process on a semiconductor wafer or the like.
• w is required to form a wiring pattern on a surface of a semiconductor wafer to be processed or to bury a recess between wirings.
• tungsten tungsten
• WS i tungsten silicide
• Ti titanium
• Ti N titanium nitride
• Ti Si titanium silicide
• a highly corrosive gas composed of a halogen compound such as WF 6 , T i C, or S i H 2 C 12 is used, and depending on the type of gas used, HC is used. Corrosive gas such as 1 is generated.
• tungsten silicide (WSiX) using (dichlorosilane)
• the process is performed in a high temperature range of about 500 to 600 ° C.
• a cleaning gas is used to remove unnecessary tungsten silicide film.
• Cleaning is performed in a temperature range of about 200 to 250 ° C. using C 1 F 3 gas.
• the unnecessary tungsten silicide film is removed by an exothermic reaction with the C 1 F 3 gas.
• FIG. 9 is a schematic configuration diagram showing a conventional general film forming apparatus.
• This film forming apparatus has a storage container 2 which can be vacuumed.
• a mounting table 6 made of, for example, amorphous carbon and supported by a cylindrical reflector 4 is provided in the storage container 2, and the semiconductor wafer W is mounted on the upper surface thereof.
• a transmission window 8 made of, for example, quartz glass is provided at the bottom of the container below the mounting table 6, and further mounts by transmitting heat rays from a plurality of heating lamps 10 rotatably arranged below. The stage 6 and the semiconductor wafer W are heated.
• a ring-shaped attachment member 14 made of, for example, aluminum or quartz and having a rectifying hole 12 is provided between the container and the inner peripheral wall of the container.
• a shield ring 16 made of, for example, amorphous carbon is placed so as to bridge between the step of the peripheral green portion of the mounting table 6 and the step of the inner peripheral side of the attachment member 14.
• the shield ring 16 has a function of substantially expanding the area of the surface of the mounting table 6 on which the wafer is mounted so that the wafer has a uniform film thickness at the peripheral edge as well as at the center. . By the action of the shield ring 16, a film having a uniform thickness is deposited on the wafer surface.
• the shield ring 16 can be attached and detached, so that the shield ring 16 can be easily cleaned as required.
• a shower head 18 made of, for example, aluminum or nickel is provided on the ceiling of the container facing the mounting table 6 in order to introduce a necessary film forming gas into the storage container 2. .
• the components mainly in the storage container 2, particularly, the components exposed to a high temperature state, for example, the surface of the mounting table 6, the shield ring 16 around the mounting table 6, and the shower head 18 are strong. There was a problem of corrosion. Disclosure of the invention
• An object of the present invention is to provide a film forming apparatus capable of improving the corrosion resistance and extending the life by increasing the surface roughness of components in a storage container.
• An object of the present invention is to provide an object to be processed on a mounting table installed in a storage container capable of being evacuated.
• the surface roughness of a component provided in the storage container is set to a standard value. It is characterized in that it is set to be larger than the surface roughness when used.
• Such a component is, for example, a mounting table, a shield ring, or a shower head.
• the material of the mounting table or shield rings, A 1 N, A 1 2 ⁇ 3, S i C, is any one of the S I_ ⁇ 2, S i N 4 and amorphous force one carbon.
• the surface roughness is set within a range of 3.0 to 10.0 m.
• the surface of the component is subjected to a plasma etching process. According to this, it becomes possible to further improve the corrosion resistance.
• the surface roughness of the component is set to a value within a range of 1.7 to 5.9 times the surface roughness when the component is normally used.
• the magnitude of the surface roughness when the component is used as a standard is determined from the viewpoint of suppressing the generation of particles from the surface of the component, the viewpoint of maintaining a high vacuum degree, or the cost of manufacturing. It is characterized in that the surface roughness is set from the viewpoint of reducing the surface roughness.
• the surface roughness Ra when the component was used as a standard is as follows.
• for Al 2 ⁇ 3 R a 0.3 to 0.5 m
• for S i ⁇ 2 R a 0.3 to 0.5 m
• Ra 0.8 to 1.0 im.
• FIG. 1 is a sectional view showing a film forming apparatus according to the present invention.
• FIG. 2 is a partially enlarged view showing the mounting table and its peripheral portion in FIG.
• FIG. 3 is an enlarged view showing a portion A in FIG.
• FIG. 4 is an enlarged view schematically showing the state of irregularities on the surface of each component in the storage container.
• FIG. 5 is an enlarged view showing a state in which a top portion of a convex portion on a concave-convex surface of a component is removed by plasma etching.
• FIG. 6 is a diagram showing the evaluation results of the corrosion resistance of the example of the present invention and the comparative example.
• FIG. 9 is a schematic configuration diagram showing a conventional general film forming apparatus.
• FIG. 1 is a cross-sectional configuration diagram showing a film forming apparatus according to the present invention
• FIG. 2 is a partially enlarged view showing a mounting table and its peripheral portion in FIG. 1
• FIG. 3 is an enlarged view showing a portion A in FIG. .
• the film forming apparatus 20 has a storage container 22 formed into a cylindrical shape or a box shape from, for example, aluminum or the like. In the storage container 22, a cylinder rising from the bottom of the storage container is provided.
• a mounting table 26 for mounting a semiconductor wafer W as an object to be processed is provided on a reflector 24 made of aluminum.
• a plurality of, for example, three (only two are shown in the illustrated example) lift bins 28 are provided so as to rise upward with respect to the support member 30.
• the support member 30 is moved up and down by a push-up rod 32 provided to penetrate the bottom of the storage container, so that the lift pin 28 provided through the mounting table 26 through the lift bin 28 is provided.
• the wafer W can be lifted by being inserted through the hole.
• the lower end of the push-up rod 32 is connected to an actuator 38 via a bellows 36 which can be expanded and contracted in order to keep the inside of the storage container 22 airtight.
• a transparent window 40 made of a heat ray transmitting material such as quartz glass is provided airtightly at the bottom of the storage container directly below.
• a box-shaped heating chamber 42 is provided.
• a plurality of heating lamps 44 as heating means are mounted on a turntable 46 also serving as a reflecting mirror, and the turntable 46 is connected to the heating chamber 42 via a rotary shaft. It is rotated by a rotating motor 48 provided at the bottom of the wing.
• the heat rays emitted from the heating lamp 44 pass through the transmission window 40 and irradiate the lower surface of the mounting table 26 to heat it.
• a resistance heater may be provided so as to be embedded in the mounting table 26.
• a ring-shaped attachment member 52 made of, for example, aluminum and having a large number of flow regulating holes 50 is provided on the outer peripheral side of the mounting table 26 so as to be supported by a support column 54.
• the mounting table 26 is made of, for example, amorphous carbon having a thickness of about 2 mm and has a stepped portion 56 formed by shaving the corner into a ring shape. Is formed. In addition, a stepped portion 59 cut in a ring shape is also formed on the inner peripheral portion of the attachment member 52 adjacent to the outer periphery. A ring-shaped shield ring 58 is provided so as to be bridged between the steps 56 and 59, and the thickness of the film deposited on the surface of the wafer W by this action is reduced. The uniformity can be improved.
• the material of the shield ring 58 is made of, for example, amorphous carbon, similarly to the mounting table 26 described above. As the material for such mounting table 2 6 and the shield ring 5 8, in addition to the amorphous carbon, A l, A 1 N, A 1 2 ⁇ 3, S i C, S I_ ⁇ 2, S i 3 N 4 etc. can also be used.
• an exhaust port 60 is provided at the bottom below the attachment member 52, and an exhaust path 62 connected to a vacuum pump (not shown) is connected to the exhaust port 60.
• the inside can be maintained at a predetermined degree of vacuum.
• a gate valve 64 that is opened and closed when a wafer is loaded and unloaded is provided on a side wall of the storage container 22.
• a shower head portion 66 for introducing a processing gas or the like into the storage container 22 is provided on a ceiling portion of the storage container facing the mounting table 26.
• the shower head section 6 6 is formed into a circular box shape using, for example, aluminum or the like. It has a head body 68, and a gas inlet 70 is provided in the ceiling.
• This gas inlet 70 gas required for film formation through a gas passage (not shown), eg if WF B, S i C 12 H2 , H2, N 2, A gas source Ri Contact connected such r The flow rate can be controlled and supplied.
• a number of gas injection holes 74 for discharging the gas supplied into the head body 68 to the processing space S are arranged substantially all over the plane. Gas is released over the wafer surface.
• a diffusion plate 78 having a large number of gas dispersion holes 76 is provided in the head main body 68 so as to supply gas more evenly to the wafer surface.
• the surface roughness of the component in the storage container 22 is set to be larger than the surface roughness when the component is normally used.
• the upper surface (mounting surface) 26A of the mounting table 26 and the surface 58A of the shield ring 58 have the same surface roughness as that of a normal standard.
• the irregularities 80 and 82 are formed to be larger than the surface roughness of.
• the lower surface (injection surface) 66 A of the shower head 66 has a surface roughness larger than that of a normal standard use, and irregularities 84 are formed. Have been.
• the surface roughness of the side surface as well as the lower surface of the shower head 66 may be increased.
• FIG. 4 is an enlarged view schematically showing the state of the irregularities 80, 82, and 84 on the surface of each of the components 26, 58, and 66, where the surface roughness is set large.
• the surface roughness Ra when the components in the storage container 22 are used as a standard means that generation of particles in the storage container 22 can be suppressed or high vacuum can be maintained. Or from the viewpoint that the manufacturing cost is not extremely high, etc., refers to the magnitude of the surface roughness that is usually set.
• the shield ring 58, the shower head 66, etc. blast the surface using alumina-based particles of a predetermined particle size. do it.
• the particle size of the alumina-based particles to be used may be selected.
• the surface roughness of the standard product is around 1.7 / m, so the surface roughness here is as described below. Set the surface roughness within the range of about 3.0 to 10.0, which is about 1.7 to 5.9 times the surface roughness of the standard product.
• the surface roughness of the standard product is about 0.4 m, so the surface roughness here is about 0.4 to 2.4. Set within the range.
• the surface roughness of the standard product is about 0.6 ⁇ m, the surface roughness of the part is 1.0 to 3 It should be set within the range of about 5.
• the film forming processing is performed directly on the wafer surface in this state. Instead, a precoating process is performed to apply a thin film of the same material as the film forming material on the surface of the component in the storage container 22.
• the same kind of gas as in the process is flowed with the wafer W not mounted on the mounting table 26, and various process conditions such as the process pressure and the process temperature are set. Under the same process conditions as above, the inner wall surface of the storage container 22, the mounting table 26, the shield ring 58, the surface of the shower head 66, etc.
• tungsten silicide WSix
• the internal environment of the storage container 22 is adjusted to maintain high reproducibility. After performing the pre-coating process in this way, next, a film forming process for actually depositing a film on the surface of the semiconductor wafer W is performed.
• the gate valve 64 provided on the side wall of the storage container 22 is opened, the wafer W is loaded into the storage container 22 by the transfer arm, and the lifter pins 28 are pushed up. Transfer wafer W to lifter pin 28 side. Then, the lifter pin 28 is lowered by lowering the push-up bar 32, and the wafer W is mounted on the mounting table 26. Then, WF «as the process gas from the process gas source (not shown), and mixed by supplying the gas required for film formation such as S i H 2 C 1 to the shower head 6 6 by a predetermined amount, this Reohe' The gas is supplied almost uniformly into the storage container 22 from the gas injection holes 74 on the lower surface of the storage body 68. At the same time, the inside of the storage container 22 is set to a predetermined degree of vacuum by suctioning and exhausting the internal atmosphere from the exhaust port 60, and the heating lamp 44 located below the mounting table 26 is rotated. Drives and emits heat energy.
• the emitted heat rays pass through the transmission window 40 and then irradiate the surface of the mounting table 26 to heat it. Since the mounting table 26 is very thin, it is quickly heated, and therefore, the wafer W mounted thereon can be quickly heated to a predetermined temperature.
• the supplied mixed gas causes a predetermined chemical reaction, and, for example, a film of tungsten silicide (WSix) is deposited and formed on the wafer surface according to the film forming conditions.
• the process pressure is, for example, about 0.1 to 5 Torr, and the process temperature is about 500 to 600 ° C.
• Such a film forming process is continuously performed on a large number of wafers, for example, 25 wafers. However, during this continuous process, if the surface of each component in the storage container 22 is peeled off, it will be damaged. Unnecessary film which causes one icle and the like adheres. Next, a cleaning process is performed to remove the film.
• a C 1 Fa gas as a cleaning gas flows from the shower head section 66 into the storage container 22 to remove unnecessary tungsten silicide film deposited on the surface of each component. It is vaporized and removed by an exothermic reaction with gas.
• the temperature of the mounting table 26 is maintained at a temperature optimal for cleaning, for example, about 200 to 250 ° C.
• each component in the storage container 22 is exposed to corrosive gas, and its surface tends to be corroded.
• the product is exposed to highly corrosive corrosive gases such as HC 1 gas and C 1 gas generated by the film formation reaction, and is exposed to the highly corrosive cleaning gas (C 1 F 3 ) itself during the cleaning process.
• C 1 F 3 highly corrosive cleaning gas
• the components such as the mounting table 26, the shield ring 58, and the shield head portion 66 have a surface roughness that is lower than the surface roughness when the surface roughness is normally used. Is set to be large, the corrosion resistance is greatly reduced, the corrosion resistance is greatly improved, and the service life can be extended.
• the contact area between the mounting table 26 and the back surface of the wafer can be reduced accordingly, so that the amount of particles adhering to the back surface of the wafer can be reduced accordingly.
• Figure 6 shows the standard results.
• the material of the test piece is all amorphous, and the surface roughness Ra of Examples 1 to 5 is variously changed to 3.0 to 7.4. Further, Example 5 is subjected to ⁇ 2 plasma etching treatment on the surface of the test piece used in Example 1.
• the surface roughness Ra of Comparative Example 1 was 1.7 m, which is an amorphous carbon part.
• the presence or absence of powder-like particles was evaluated by bonding a carbon tape to the surface of the test piece and peeling it off.
• Example 1 to 5 in which the surface roughness was 3.0 or more, the number of durable cycles was larger than that in Comparative Examples 1 and 2, and increased to 19 to 40 times. This shows that the corrosion resistance is improved and is preferable.
• the number of durable cycles was 40, but this number was sufficient for the durability, and the test was stopped more times. It seems that the number of endurance cycles will further increase.
• Example 1 there was peeling of the powder particles, in Examples 2 and 3, the peeling of the powder particles was slight, and further, in Example 4, the peeling of the powder particles was eliminated. The greater the value, the better the corrosion resistance.
• the surface roughness exceeds 10.0 m, the film deposited on the apex of the protrusion on the uneven surface of the test piece will peel off and cause particles to be generated.
• Example 1 As is apparent from a comparison between Example 1 and Example 5, even when the surface roughness is the same, the number of durable cycles is reduced from 19 times by performing plasma etching on the surface as in Example 5. It extended up to a few times, and the surface of the powder particles did not peel off, indicating that the corrosion resistance could be further improved.
• Figure 7 shows electron micrographs of the surface of Example 2 with a surface roughness Ra of 4.3 ⁇ m before and after the experiment, (A) shows a photograph before the corrosion experiment, and (B) shows a photograph before the corrosion experiment. The photograph of is shown. According to this, fine carbon fragments can be seen on the entire surface after the experiment, but they do not fall out and have large holes unlike the case where the surface roughness Ra shown in Fig. 8 is 1.7 m. It could be observed that it did not peel off.
• Figure 8 shows electron micrographs of the surface of Comparative Example 1 with a surface roughness Ra of 1.7 m before and after the experiment, (A) shows a photograph before the corrosion experiment, and (B) shows a photograph after the corrosion experiment. A photograph is shown. According to this, after the experiment, it was observed that there was a large hole, and that irregularities were widened as if carbon had fallen off on the surface.
• the case where WF ( ; or SiH 2 C 12 is used as a film forming gas and C 1 F 3 gas is used as a cleaning gas has been described as an example.
• the object to be processed is not limited to a semiconductor wafer, and the apparatus of the present invention can be applied to an LCD substrate, a glass substrate, and the like. According to the device, the following excellent operational effects can be exhibited.
• the amount of unnecessary film formed per unit area is reduced, and the calorific value of the portion is reduced, or the surface temperature is reduced. Corrosion can be improved.
• the corrosion resistance can be further improved.

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Citations (6)

• 1999
  • 1999-06-03 JP JP15687199A patent/JP4461507B2/ja not_active Expired - Fee Related
• 2000
  • 2000-05-25 WO PCT/JP2000/003358 patent/WO2000075971A1/ja active Application Filing
  • 2000-06-02 TW TW89110803A patent/TW484175B/zh not_active IP Right Cessation

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