JP2008135661A - Method of cleaning semiconductor processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method with no risk in contamination removal, regardless of conditions of a cleaning objective surface. <P>SOLUTION: When aiming at a treating semiconductor substrate installation electrode 107, to which two or more contaminations A-M of sub-micron size shown in Fig. (a) adhere on its surface, as shown in Fig. (b) the surface is coated with fluid substance 3, such as solution of water with suspended polyvinyl acetate resin without including heavy metal. Although the solution shows a shape of loose starch sirup having suitable viscosity and moderate mobility before application, it is semi-cured by drying treatment and becomes the shape of semi-solid with high consistency from half-mobility. When the fluid substance 3 is cured moderately and becomes a film shape like harder jelly after drying treatment, the film-shaped fluid substance 3 is peeled from the substrate installation face of the substrate installation electrode 107 as shown in Fig. (c), and contaminations A-M buried in the fluid substance 3 are peeled together from the substrate installation face of the substrate installation electrode 107 so that substrate installation face of the substrate installation electrode 107 is mead clean without contaminations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for cleaning a semiconductor processing apparatus, and more particularly to a cleaning method for a member in a semiconductor processing apparatus that contacts a semiconductor substrate to be processed.

  In the manufacture of semiconductor devices, foreign matter on the submicron level affects each manufacturing process. For example, in a semiconductor device etching process, when a foreign substance adheres to a semiconductor substrate to be processed, the foreign substance may not serve as a mask to form an accurate electrical circuit, which may result in a decrease in manufacturing yield. Moreover, in recent years, semiconductor devices have been further miniaturized, and therefore, even fine foreign matters have become a problem.

  By the way, the foreign matter at this time is generated due to various factors. One of the factors is that the foreign matter adhering to the back surface of the semiconductor substrate to be processed is once in the processing apparatus when the semiconductor substrate to be processed is moved or cleaned. It is conceivable that the material is transferred to the member, and further transferred to the next semiconductor substrate to be processed. At this time, mixing of a heavy metal component into the semiconductor device also deteriorates the device characteristics, so that it is required to eliminate it as much as possible. A typical example of a member in such a processing apparatus is a semiconductor substrate mounting electrode (hereinafter abbreviated as a substrate mounting electrode) in a plasma etching apparatus.

  First, the plasma etching apparatus will be described with reference to FIG. Here, FIG. 2 shows an apparatus called a UHF wave ECR plasma etching apparatus as an example of a plasma etching apparatus. In the figure, first, 100 is a processing chamber, then 101 is an antenna, and 101a is a shower. Plate, 102 is a high frequency power source, 103 is a matching filter circuit, 104 is a coil, 105 is plasma, 106 is a sleeve (side wall sleeve), 107 is a substrate mounting electrode, that is, a semiconductor substrate mounting electrode, and 108 is a processing target A substrate (processed semiconductor substrate), 109 is a matching filter circuit, 110 is an RF bias power source, 111 is a susceptor, 112 is an electrode cover, and 113 is a turbo molecular pump.

  At this time, the processing chamber 100 is partitioned as a vacuum container by a processing chamber side wall 203 having a substantially cylindrical shape, a vacuum chamber side wall 204 below the processing chamber side wall 203, and a lid (lid) 201 that seals the upper portion thereof. A substrate mounting electrode 107 is provided inside. Then, the processing chamber 100 is once evacuated to a substantially vacuum, and then an etching gas serving as a processing gas is introduced therein.

As the etching gas at this time, a gas such as argon (Ar), carbon tetrafluoride (CF ₄ ), trifluoromethane (CHF ₃ ), nitrogen (N ₂ ), etc. is selected and mixed. The gas is introduced into the processing chamber 100 from a cylinder (not shown) via a gas pipe or a mass flow controller. At this time, a shower plate 101a having a large number of fine holes is formed below the antenna 101. The introduced gas is supplied between the shower plate 101 a and the antenna 101.

  Therefore, the etching gas supplied between the shower plate 101a and the antenna 101 passes through the fine holes of the shower plate 101a and is supplied in a shower shape into the processing chamber 100, so that the substrate mounting electrode 107 is mounted on the substrate. A processing gas is supplied into the processing chamber 100 from above the substrate to be processed 108 placed on the mounting surface so as to face the substrate. At this time, the inside of the processing chamber 100 is adjusted to a desired pressure by a variable valve (not shown).

  At this time, a susceptor 111 formed in a ring shape so as to surround the outer periphery thereof is placed on the substrate placement surface of the substrate placement electrode 107, and below the upper surface peripheral portion of the substrate placement electrode 107, An electrode cover 112 made in a substantially cylindrical shape is provided so as to cover the side wall portion, and a member that covers the upper portion of the substrate mounting electrode 107 except for the substrate mounting surface together with the susceptor 111 and protects it is configured. is doing.

  On the other hand, the high-frequency power source 102 generates, for example, UHF power having a frequency of 450 MHz and RF power having a frequency of 13.56 MHz, and supplies the RF power to the antenna 101 via the matching filter circuit 103 so that UHF electromagnetic waves are introduced into the processing chamber 100. Like that. At this time, the antenna 101 is held inside the lid 201 by the insulating ring 202, and the periphery of the shower plate 101 a is also held by the lid 201 by the insulating ring 202.

  In addition, a coil 104 is disposed around the processing chamber 100, and a magnetic field generated by the coil 104 is also formed in the processing chamber 100 together with the UHF electromagnetic wave. As a result, an ECR discharge is generated by the interaction between the UHF electromagnetic wave and the magnetic field. As a result, the etching gas is dissociated and the plasma 105 is formed. This is why this is called a UHF wave ECR plasma etching apparatus.

  Here, the coil 104 functions to form a magnetic field in the processing chamber 100 as described above. For this reason, a plurality of coils 104 are arranged so as to surround the upper surface and the upper part of the processing chamber 100. At this time, the plurality of coils are grouped as a coil portion 104a as shown in the figure. It is configured.

  The substrate mounting electrode 107 is attached below the processing chamber 100 so that the substrate mounting surface is horizontal with the substrate mounting surface facing upward, and a substrate to be processed 108 having a diameter of 200 mm, for example, is mounted thereon. Then, an etching process is performed. At this time, an RF bias voltage having a frequency of, for example, 800 KHz is applied to the substrate mounting electrode 107 via the matching filter circuit 109 from the RF bias power supply 110. Thus, ions in the plasma are attracted onto the substrate to be processed 108, and anisotropic etching proceeds by an ion assist reaction that interacts with radicals adsorbed on the surface. Note that a reaction product is generated during the etching, and this is exhausted by the turbo molecular pump 113.

  Here, at the time of etching, it is general to control the temperature of the substrate to be processed 108. For this reason, helium gas is introduced between the substrate mounting electrode 107 and the substrate to be processed 108, so that the thermal conductivity is increased. Is improving. At this time, in order to stabilize the thermal conductivity, a DC voltage is applied to the substrate mounting electrode 107 from a power supply device (not shown), and the substrate 108 is attracted and held by the substrate mounting electrode 107 by electrostatic force. ing.

  Accordingly, if foreign matter remains on the surface of the substrate placement electrode 107 at this time, the foreign matter is transferred to the back surface of the semiconductor substrate 108 to be processed by electrostatic force. The surface of the electrode 107 needs to be cleaned.

  Therefore, a certain prior art has proposed a method of providing a cleaning tool by providing an adhesive layer on the surface of a plate member (see, for example, Patent Document 1).

In this method, the surface on which the adhesive layer of the cleaning tool is provided is contacted with the semiconductor substrate to be processed in advance in the processing apparatus, for example, a member considered to have transferred foreign matter, for example, the processing target Press against the surface of a so-called member to be cleaned, such as a semiconductor substrate mounting electrode, and capture the foreign matter adhering to it with the adhesive layer of the cleaning tool, thereby removing the foreign matter on the surface of the member, and consequently The foreign matter on the back surface of the semiconductor substrate to be processed can be reduced.
Japanese Patent Laid-Open No. 10-32488

  In the above prior art, consideration is not given to the diversification of the material of the member to be cleaned, and there has been a problem in removing foreign matters when targeting semiconductor devices that have been further miniaturized in recent years. That is, in recent years, members that contact the semiconductor substrate to be processed in the processing apparatus have been diversified, and as a result, the surface of the member is also made of a sintered material or a sprayed material. If the state is seen finely, it will show a considerable uneven surface.

  For this reason, as shown in FIG. 5, in the method using the plate member cleaning tool as in the prior art, the adhesive layer is not brought into contact with the foreign matter adhering to the concave surface portion. As a result, the trapping action by the adhesive layer is not exhibited, and there are cases where foreign matters cannot be removed efficiently, and as described above, problems arise in foreign matter removal.

  Here, FIG. 5 will be described in more detail. This figure shows, as a typical example, the case where the member to be cleaned is the substrate mounting electrode 107, and this is, for example, a member whose surface is made of a sprayed film. The case is shown as an example, and in this case, the surface of the sprayed film has considerable unevenness when viewed finely. Therefore, first, in FIG. 5 (a), when a large number of foreign matter A to M adheres to the surface, that is, the substrate mounting electrode 107 whose substrate mounting surface is uneven, the surface is turned up. The surface irregularities and the sizes of the foreign substances A to M are exaggerated for easy understanding.

  Next, in FIG. 5B, the cleaning tool T according to the prior art is applied to the substrate mounting electrode 107 in the state shown in FIG. 5A, and the adhesive layer S of the plate member is provided. In this case, the foreign material A to M is attached to a portion that is convex on the surface of the substrate mounting electrode 107. Only foreign matter, that is, foreign matters A, B, F, I, and M are in contact with the adhesive layer S of the cleaning tool T, but foreign matter attached to the recessed portion, that is, foreign matters C, D, E, G, H, J, K, and L show a state where the adhesive layer S is not in contact.

5 (c) shows a case where the cleaning tool T in the state shown in FIG. 5 (b) is separated from the substrate mounting electrode 107. In this case, the cleaning tool T is in contact with the adhesive layer S. Only foreign matters, that is, foreign matters A, B, F, I, and M are removed together with the cleaning tool T, but foreign matters, that is, foreign matters C, D, E, G, H, J, K, and L are not. It remains on the surface of the substrate mounting electrode 107, and therefore the foreign matter is not sufficiently removed by the prior art, and thus a problem occurs in removing the foreign matter. It is an object of the present invention to provide a cleaning method that does not cause a problem in removing foreign matter regardless of the above.

  In order to achieve the above object, according to the present invention, in a method for cleaning a member that contacts a substrate to be processed of a semiconductor processing apparatus, the surface of the member is changed from a liquid to a semi-solid with a high consistency by a curing process. And a step of applying a flowable material, a step of curing the material to form a semi-solid film, and a step of peeling the material cured to a semi-solid film from the member. Is.

  At this time, in the present invention, when the liquid material is applied, the viscosity is adjusted so that the liquid material follows the uneven surface and wraps particles remaining on the uneven surface. Thereafter, the applied substance takes in foreign matter on the surface of the member into the substance. The applied substance has flexibility after drying, and is peeled off while the foreign substance is taken into the integrally solidified substance, so that the foreign substance remaining on the surface of the member in contact with the substrate can be efficiently removed.

  As described above, according to the present invention, foreign matters remaining on the surface of the member on which the semiconductor substrate to be processed is placed can be efficiently removed. The manufacturing problems related to foreign matter on the back side of the processed substrate can be improved.

  In addition, since the liquid coating material used in the present invention does not contain a heavy metal component, there is no fear of deteriorating the characteristics of the semiconductor device, and thus a highly reliable semiconductor device with high production efficiency can be obtained. Can be manufactured.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  Here, FIG. 1 is an explanatory view of an embodiment in which the cleaning method according to the present invention is applied to a processing substrate mounting electrode of a plasma etching apparatus, that is, a substrate mounting electrode. The substrate mounting electrode 107 in FIG. 2 is shown as an object to be cleaned. FIG. 1A shows a case where a large number of foreign substances A to M have adhered to the substrate mounting electrode 107 having an uneven surface on the substrate mounting surface. It is assumed that the processing is performed. In this case as well, the unevenness of the substrate placement surface of the substrate placement electrode 107 and the size of each foreign substance are exaggerated.

Therefore, it is assumed that the cleaning process according to the present invention has been started for the substrate placement electrode 107 in the state of FIG. Then, in this case, first, a process of applying a semi-fluid substance to the substrate placement surface of the substrate placement electrode 107 in the state of FIG. FIG. 1 (b) shows the state at this time, and reference numeral 3 denotes the semi-fluid substance described above.
And the semi-fluid substance at this time is a substance that becomes a semi-solid state from a liquid to a highly viscous state by a curing treatment, such as a solution in which a vinyl acetate resin is suspended in water. It has a loose water tank shape with moderate fluidity at a viscosity of, but it is semi-cured by treatment such as drying, it becomes a semi-solid state of semi-fluid to highly viscous jelly, and contains heavy metals It is not a substance.

  At this time, as described in FIG. 2, the substrate mounting electrode 107 is held horizontally with its substrate mounting surface facing upward. Accordingly, when the semi-fluid substance 3 is applied, an appropriate amount is dropped in consideration of the size of the substrate placement surface of the substrate placement electrode 107 and the viscosity of the water-like semi-fluid substance 3 as shown in the figure. In addition, the bottom surface is spread over a substantially flat surface while filling the irregularities on the substrate mounting surface. At this time, if necessary, the application state may be adjusted with a spatula-like member or the like.

  In addition, at this time, the surface tension of the semi-fluid substance 3 itself is adjusted so that it naturally spreads to the periphery of the substrate mounting surface of the substrate mounting electrode 107 or does not drop from the periphery, as shown in FIG. The situation can be easily created. In the state of FIG. 1B, a large number of foreign substances A to M on the substrate placement surface of the substrate placement electrode 107 are embedded in the lower surface of the semi-fluid substance 3.

  In addition, at this time, by appropriately selecting the viscosity of the semi-fluid material 3, it is possible to fill the fluid material 3 without leaving all the unevenness on the substrate mounting surface. Therefore, according to this embodiment, all of the many foreign substances A to M can be surely embedded in the lower surface of the semi-fluid substance 3.

  Therefore, after this, the fluid substance 3 is subjected to a curing treatment. At this time, when a solution obtained by suspending the above-described vinyl acetate resin in water is used as the fluid substance 3, it is simply a predetermined time. All that is required is to wait and wait for the moisture to evaporate and dry properly, so that a moderately cured state can be easily achieved.

  Thus, when the fluid substance 3 applied to the substrate placement surface of the substrate placement electrode 107 is appropriately cured to form a hard gelatin film, then, as shown in FIG. The film-like fluid substance 3 is peeled off from the substrate placement surface of the substrate placement electrode 107. At this time, the foreign substances A to M are embedded in the lower surface of the fluid material 3 cured in a film shape, and the fluid material 3 is firmly held by the fluid material 3 due to the curing of the fluid material 3. Yes.

  Accordingly, when the film of the fluid substance 3 that has been appropriately cured is peeled off from the substrate placement surface of the substrate placement electrode 107, the foreign substances A to M embedded in the fluid substance 3 are also removed from the substrate placement surface as shown in the figure. The substrate placement surface of the placement electrode 107 is peeled off together, and as a result, the substrate placement surface of the substrate placement electrode 107 is brought into a clean state free from foreign matter. Then, after that, if the film of the fluid substance 3 that has been peeled off is discarded, the cleaning process of the substrate mounting electrode 107 is completed.

  Therefore, as a result, the subsequent etching process of the semiconductor device by the plasma etching apparatus can be executed with a high yield. In addition, since the flowable material 3 used at this time does not contain a heavy metal component, there is no possibility that the device characteristics are deteriorated. Therefore, according to this embodiment, performance deterioration due to metal contamination does not occur. In this respect, the semiconductor device manufacturing yield can be improved.

  Next, the procedure of the cleaning process according to this embodiment will be described in more detail. First, in the case of the plasma etching apparatus targeted here, the substrate mounting electrode 107 is plasma as shown in FIG. Therefore, as the number of substrates 108 to be processed and etched thereon increases, the substrate mounting electrode 107, particularly on the mounting surface thereof, is in the processing chamber 100 in which the substrate 105 is formed. The amount (number) of remaining foreign matter also increases.

  Therefore, in this embodiment, the cleaning process is started when a predetermined time set in advance is reached. For this reason, for example, during the plasma etching process, the number of processed substrates 108 is counted, and the cleaning process is started when the number of processed substrates reaches a predetermined number set in advance, as described in FIG. A cleaning process with the semi-fluid substance 3 is performed.

  When the cleaning process is started, first, all the gas introduction passages and the evacuation passages communicating with the processing chamber 100 are closed. Next, after reducing the pressure in the processing chamber 100 to approximately atmospheric pressure, the lid 201 is opened as shown in FIG. For this reason, the lid 201 is connected to the upper end of the processing chamber side wall 203 by a hinge mechanism 205. By removing the bolt that fastens and fixes the lid 201 to the processing chamber side wall 203, an arrow A in FIG. It can be opened as shown.

  At this time, the coil portion 104 a is on the lid 201. Therefore, first, as shown by an arrow B by means of a crane or the like (not shown), the coil unit 104a is lifted and moved to a position removed from the plasma etching apparatus, and a space necessary for opening the lid 201 in advance is provided. Make sure it is secured.

  Thus, when the lid 201 is opened as shown in FIG. 3, first, the susceptor 111 and the electrode cover 112 are removed. Next, as shown in FIG. 4, the substrate placement electrode 107 is removed from the base 207 of the substrate placement electrode 107 as shown by an arrow C, taken out of the processing chamber 100, and is not shown. Place on the work table. Next, the substrate mounting electrode 107 is subjected to a cleaning process according to the embodiment of the present invention described with reference to FIGS. 1 (a) to 1 (c).

  Then, after the cleaning process is completed, first, the substrate mounting electrode 107 is carried into the processing chamber 100 and installed on the pedestal 207. Next, the susceptor 111 and the electrode cover 112 are attached to the substrate mounting electrode 107, and then the lid 201 is closed and the coil portion 104a is returned to the original position. Thereafter, until the predetermined time comes, an etching process of the semiconductor device by the plasma etching apparatus can be obtained with a high yield.

  Incidentally, in the example described above, an example in which the cleaning method according to the embodiment of the present invention is applied to the substrate placement electrode 107 taken out from the processing chamber 100 has been described. As an example, the substrate mounting electrode 107, the susceptor 111, and the electrode cover 112 that have been subjected to the cleaning method according to the embodiment of the present invention may be prepared as separate units and replaced with them. During the cleaning process, the stop time of the plasma etching apparatus can be reduced.

  In addition, after the lid 201 of the processing chamber 100 is opened, the substrate mounting electrode 107 is placed on the substrate mounting electrode 107 in the processing chamber 100 simply by removing the susceptor 111 and the electrode cover 112 while the substrate mounting electrode 107 is placed on the base 207. The cleaning method according to the embodiment of the present invention may be applied, and in this case, work such as removal, removal, and carry-in of the substrate mounting electrode 107 is not necessary, so that work time required for maintenance can be shortened. On the other hand, in the cleaning process, care must be taken so that the fluid substance 3 does not adhere to portions other than the substrate placement electrode 107 in the processing chamber 100.

  By the way, although the above embodiment demonstrated the case where this invention was applied to the plasma processing apparatus for the cleaning of the substrate mounting electrode 107 and semiconductor manufacture, the substrate mounting electrode at the time of manufacturing a plasma processing apparatus is demonstrated. It may be applied to cleaning, and in this case, the generation of foreign matter at the initial operation can be reduced.

It is a schematic diagram for demonstrating the cleaning process method which concerns on this invention. It is explanatory drawing which shows an example of the semiconductor plasma etching apparatus which is an application object of this invention. It is explanatory drawing at the time of applying the cleaning treatment method which concerns on this invention to a semiconductor plasma etching apparatus. It is explanatory drawing at the time of applying the cleaning treatment method which concerns on this invention to a semiconductor plasma etching apparatus. It is a schematic diagram which shows an example of the prior art for a foreign material removal.

Explanation of symbols

3: Flowable material 100: Processing chamber 101: Antenna 102: High frequency power supply 103: Matching filter circuit 104: Coil 105: Plasma 106: Sleeve 107: Substrate placement electrode (processed semiconductor substrate placement electrode)
108: Substrate to be processed (Semiconductor substrate to be processed)
109: Matching filter circuit 110: RF bias power supply 111: Sasebuta 112: Electrode cover 113: Turbo molecular pump 201: Lid (lid)
202: Insulating ring 203: Side wall of the processing chamber 204: Side wall of the vacuum chamber 205: Hinge mechanism 207: Base A to M: Foreign matter

Claims (3)

In a method for cleaning a member in contact with a substrate to be processed of a semiconductor processing apparatus,
A step of applying a fluid substance that becomes a semi-solid with a high viscosity from a liquid by a curing process on the surface of the member;
Curing the substance to form a semi-solid film;
And a step of peeling the substance cured in a semi-solid film form from the member. The cleaning method according to claim 1,
A cleaning treatment method, wherein the fluid substance does not contain a heavy metal as a component. In the cleaning method of Claim 1 or Claim 2,
A cleaning treatment method, wherein the fluid substance is a substance containing vinyl acetate resin and water.

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