JP2006351696A - Member for semiconductor processing apparatus and semiconductor processing apparatus equipped with member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a member for semiconductor processing apparatus for controlling radicals in the semiconductor processing apparatus not to become superfluous and preventing corrosion of the member or unnecessary etching on a device surface of a wafer. <P>SOLUTION: In the semiconductor processing apparatus, respective members provided in a processing chamber 2, i. e. a gas introduction opening 8, the inner wall 2a, a shower nozzle 17, a stage 3, and an exhaust port 5, are covered with a material containing nickel by deposition or electroplating. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor processing apparatus member and a semiconductor processing apparatus used for processing an object to be processed using plasma generated by irradiating a process gas with microwaves.

  As a device for processing an object to be processed such as a silicon wafer for manufacturing a semiconductor device or a glass substrate for a liquid crystal display, there is a semiconductor processing apparatus for performing a dry etching process or an ashing process on the object to be processed using microwave plasma. . Surface processing such as fine processing and thin film formation by plasma technology using this semiconductor processing apparatus has become indispensable for high integration of semiconductor devices, for example.

  Thin film formation by such a semiconductor processing apparatus is performed by chemical vapor deposition (CVD method). In particular, the plasma CVD method has been widely used in recent years because a film can be formed at a low temperature. In this method, a gas containing a raw material (reaction gas) is excited and activated (plasmaized) to cause a chemical reaction on the wafer to form a thin film on the wafer.

  By the way, in such a thin film forming method, a thin film is formed not only on the front surface of the wafer, that is, on the device surface but also on the back surface. In such a case, it is necessary to remove the thin film formed on the back surface of the wafer. Normally, after applying a resist on the device surface side of the wafer, the device surface side is etched by applying a tape or the like as a protective film. The back side was etched by wet etching or dry etching (see Patent Document 1).

In particular, in dry etching, utilizing the fact that H ₂ gas or the like has an action of deactivating radicals (see Patent Document 2), the wafer is inverted, and H ₂ gas is allowed to flow on the device surface side from the wafer back side. It has also been carried out to suppress etching on the device surface side by deactivating radicals that come around.

In the above method, when the film is formed on the wafer, the product generated by the reaction of the reaction gas constitutes not only the wafer but also the reaction chamber of the semiconductor processing apparatus, for example, an inner wall, a heat insulating material, a shower nozzle, It also adheres to the surface of members such as plasma traps, domes, electrodes, susceptors, stages, chucks, focus rings, lids and pipes, forms films, peels off as fine particles after a long period of operation, and scatters into the reaction chamber. End up. Therefore, also in this case, the deterioration of the semiconductor processing apparatus member due to such radicals has been prevented by utilizing the effect that H ₂ gas or the like deactivates the radicals (see Patent Document 2).
JP-A-10-189531 JP-A-10-256185

  However, even when a protective tape or the like is applied to the device surface side in dry etching on the backside of the wafer as described above, the tape or the like may be peeled off due to mechanical contact between the wafer and the support member, or a gap between the tape or the like and the wafer. Therefore, radicals may enter through such a small gap, and as a result, the device surface side may be etched.

  Even if the wafer is directly placed on a stage or the like, since the device surface is sealed only by the weight of the wafer, radicals enter through a minute gap formed by distortion of the stage and the wafer itself. As a result, the device surface may be etched.

In addition, the method of introducing a gas that deactivates radicals such as H ₂ cannot completely prevent the reaction gas decomposition products or radicals from contacting the inner wall of the processing chamber, and results in long-term operation. In some cases, a reaction gas decomposition product is deposited on each member in the processing chamber or each member is etched.

  The present invention has been proposed on the basis of recognition of such a problem, and an object of the present invention is to prevent deposition and etching of reaction gas decomposition products on members of a semiconductor processing apparatus, and to eliminate unnecessary wafer device surfaces. An object of the present invention is to provide a semiconductor processing apparatus member for preventing etching and a semiconductor processing apparatus including the same.

  In order to achieve the above object, a first aspect of the present invention provides a vacuum processing chamber and a semiconductor processing apparatus member for processing a workpiece by exciting a reaction gas introduced into the processing chamber with plasma. It is characterized in that at least a part is covered with a material containing nickel.

  According to the first aspect of the present invention, excessive radicals can be deactivated by covering various members constituting the processing chamber of the semiconductor processing apparatus with a material containing nickel. As a result, it is possible to prevent the reaction gas decomposition products from being deposited and etched on the members of the semiconductor processing apparatus, and to prevent unnecessary etching on the device surface of the wafer.

  According to a second aspect of the present invention, in the first aspect of the present invention, a stage for mounting the semiconductor processing apparatus is provided in the processing chamber, and the stage is provided adjacent to the mounting surface. A non-mounting surface, and at least a part of the non-mounting surface is covered with nickel.

  When performing backside etching of a semiconductor device, when a protective tape or the like is applied to the device surface side of the semiconductor device or when the semiconductor device is sealed only by its own weight with respect to the stage, radicals are generated from the gap generated on the device surface side of the semiconductor device. As a result, the device surface side is etched. However, in the invention according to claim 2, even if such excessive radicals are deactivated by covering the stage around the semiconductor device with a material containing nickel and a gap is generated on the device surface side, the device surface side is Etching can be prevented. Also, in the film formation, excessive radicals are deactivated, and deposition of unnecessary reaction gas decomposition products can be prevented.

According to a third aspect of the present invention, in the first aspect of the present invention, the treatment chamber is provided at a position in contact with radicals.
In the invention according to claim 3 as described above, excessive radicals can be deactivated by providing various members constituting the processing chamber of the semiconductor processing apparatus covered with the nickel-containing material at positions where the radicals come into contact. . As a result, it is possible to prevent unnecessary deposition or unnecessary etching of reaction gas decomposition products on the semiconductor processing apparatus member or wafer.

According to a fourth aspect of the present invention, a semiconductor processing apparatus includes the member for a semiconductor processing apparatus according to any one of the first to third aspects.
The invention described in claim 4 as described above is provided with a semiconductor processing apparatus member in which various members constituting a processing chamber of the semiconductor processing apparatus are covered with a material containing nickel, thereby contributing to unnecessary deposition and etching. Radicals can be deactivated. Thereby, it is possible to prevent unnecessary deposition and unnecessary etching of reaction gas decomposition products on the semiconductor processing apparatus and the wafer.

  In the present invention as described above, excessive radicals can be deactivated by covering various members constituting the processing chamber of the semiconductor processing apparatus with a material containing nickel. This makes it possible to prevent unnecessary reactive gas decomposition products from being deposited and etched on the semiconductor processing apparatus member and the device surface of the wafer.

  Next, an embodiment of the present invention (hereinafter referred to as an embodiment) will be specifically described by taking a chemical dry etching apparatus (CDE apparatus) as an example. Since the CDE apparatus and the CVD apparatus are equivalent from the viewpoint of deactivating excessive radicals, the present invention can be applied to any apparatus.

  The semiconductor processing apparatus of the present embodiment (hereinafter also simply referred to as “this apparatus”) includes a vacuum container 1 having a processing chamber 2 provided therein as shown in FIG. A stage 3 is provided inside the processing chamber 2, and a wafer W is placed on the stage 3. The stage 3 is provided with a temperature adjustment mechanism (not shown) so that the temperature of the wafer W can be controlled by this temperature adjustment mechanism. In the present embodiment, the workpiece on the stage is a wafer, but the present invention can also be used for processing a glass substrate for a liquid crystal display device, for example.

  An exhaust port 5 is formed in the bottom plate 4 of the vacuum vessel 1, and an exhaust pipe 6 having one end connected to a vacuum pump (not shown) is attached to the exhaust port 5. Further, a gas introduction port 8 is formed at the center of the upper lid 7 constituting the top plate of the vacuum vessel 1, and a gas introduction tube 9 made of a fluororesin is attached to the gas introduction port 8.

A plasma generation chamber member 10 is connected to the gas introduction tube 9. As a material for forming the plasma generation chamber member 10, a dielectric material is used. For example, quartz (SiO ₂ ), alumina (Al ₂ O ₃ ), sapphire, aluminum nitride, or the like can be used.

  A sealing member 11 is attached to the other end of the plasma generation chamber member 10, and a gas flow path 19 is formed inside the sealing member 11. A gas transport pipe 18 is connected to the sealing member 11, and a gas control unit 20 that supplies ashing gas to the plasma generation chamber member 10 is provided at the other end of the gas transport pipe 18.

  In the middle of the plasma generation chamber member 10, radical generation means including a microwave waveguide 12, that is, a plasma generation device 13 is provided so as to surround the plasma generation chamber member 10, and is surrounded by the plasma generation device 13. A plasma generation chamber 14 is formed inside the plasma generation chamber member 10. Thus, the plasma generation chamber 14 is installed outside the vacuum vessel 1. A microwave generator 15 is connected to the microwave waveguide 12.

  Further, in order to uniformly supply radicals introduced into the processing chamber 2 through the gas inlet 8 provided in the upper lid 7 (top plate) of the vacuum vessel 1 over the entire surface of the wafer W, the processing chamber A shower nozzle 17 is provided so as to form a gas storage chamber 16 in the upper part of 2. The shower nozzle 17 has a number of gas outlets.

  In the present embodiment, each member provided in the processing chamber 2 as described above, that is, the gas introduction port 8, the inner wall 2 a, the shower nozzle 17, the stage 3, and the exhaust port 5 is formed by a method such as vapor deposition or electroplating. Covered with nickel-containing material.

  Here, a case where the stage 3 is covered with a material containing nickel will be described as an example. As described above, when the back surface etching of the wafer W is performed with the CDE apparatus, even if a protective tape or the like is attached to the device surface side, the tape may be peeled off due to the mechanical contact between the wafer W and the stage 3, or the tape and the wafer. Since a gap is formed with W, radicals enter from such a slight gap, and as a result, the device surface side is etched. Even if the wafer W is directly placed on the stage 3, since the device surface is sealed only by the weight of the wafer W, radicals enter through a minute gap formed by distortion of the stage 3 and the wafer W itself. As a result, the device surface is etched.

  Therefore, in this embodiment, as shown in the enlarged view of FIG. 2, the surface of the ring-shaped stage 3 is covered with a material containing nickel. The range covered with the nickel-containing material is the wide diameter portion 3a and the tapered portion 3b on the surface of the ring-shaped stage 3, and the small diameter portion 3c on which the wafer W is directly placed is not coated. This is to avoid metal contamination due to contact of the wafer W with metal, and this portion is subjected to fluororesin processing using Teflon (registered trademark) or the like. The material of the stage 3 is not particularly limited, but is preferably made of aluminum. Moreover, the thickness of the material containing nickel is not particularly limited, but in the present embodiment, it is 10 to 50 microns.

  In addition, the site | part covered with the material containing nickel of the above stages 3 is not limited to the above cases, For example, it is good also as only the taper part 3b. Further, when the taper portion 3b is covered with a material containing nickel, the effect is high if it is performed up to the vicinity of the wafer W. In addition, as shown in FIG. 3, it may be provided on the stage 3 by being divided at equal circumferential positions. In this case, if the area covered with the nickel-containing material is reduced, the degree of radical deactivation is reduced. Therefore, the degree of radical deactivation can be adjusted by appropriately changing the area of the covered part.

  FIG. 4 shows a comparative example of the etching rate of the device surface of the wafer W when the stage 3 is covered with nickel in the form shown in FIG. 2 and when the stage 3 is covered with a fluororesin. The figure shows the average and maximum values of the etching rate of the device surface at a point of a distance of 5 mm and a point of 3 mm from the end surface of the wafer W to the center, with the etching film type being SiN (silicon nitride).

  According to this, at a distance of 5 mm, the etching rate of the device surface when covered with a fluororesin was 0.19 nm / min on average and 0.72 nm / min at the maximum, but covered with nickel In this case, the average is 0.04 nm / min, and the maximum is 0.12 nm / min.

  Further, at a distance of 3 mm, the average is 0.28 nm / min and the maximum is 1.32 nm / min when covered with a fluororesin, whereas the average is 0. It is 06 nm / min, and the maximum is 0.18 nm / min.

  Thus, it can be seen that the etching amount on the device surface side is considerably reduced by covering the surface of the stage 3 with nickel.

Next, FIG. 5 is used to show the difference in etching rate when the stage 3 in this apparatus is covered with solid aluminum, polytetrafluoroethylene (PTFE), which is a fluororesin, alumite, and nickel. In any case, the processing conditions are as follows. As a process gas, a mixed gas with CF ₄ of 400 sccm (standard cubic centimeter per minute), O ₂ of 320 sccm, and N ₂ of 80 sccm is used, pressure of 90 Pa (pascal), and microwave power. 700 W (watts). The diameter of the wafer is 300 mm.

  As shown in FIG. 5, when the stage is covered with solid aluminum, PTFE, and anodized, the etching rate rapidly increases when the distance from the center of the wafer W exceeds 145 mm. On the other hand, when the stage is covered with nickel, the change in the etching rate is gentle until the distance from the center of the wafer W exceeds 148 mm, and remains at about 8 A / min even at a position of 149 mm.

  Thus, by covering the surface of the stage 3 with nickel, it is easier to deactivate the solid radicals and anodized, which are usually considered to easily deactivate the radical, and the etching rate near the wafer edge on the device surface side is increased. And etching on the device surface side can be prevented.

  Further, by using such deactivation characteristics of nickel radicals, various members constituting the processing chamber of the semiconductor processing apparatus, that is, the gas inlet port 8, the inner wall 2 a, the shower nozzle 17, the stage 3, the exhaust port 5, etc. By covering with nickel, it is possible to prevent a problem that radicals are deactivated, adhere to and accumulate on the surface of each member in the processing chamber, peel off as fine particles, and scatter in the reaction chamber. If the entire surface of a member through which radicals pass, such as the shower nozzle 17, is covered with nickel, the degree of radical deactivation may be excessively covered. In this case, the uniformity of etching and the etching rate can be adjusted by adjusting the area covered with nickel.

[Other embodiments]
In addition, this invention is not limited to the said embodiment, It can apply also to other embodiment which is illustrated below. In the above-described embodiment, a so-called chemical dry etching (CDE) type semiconductor processing apparatus has been described. However, the plasma processing of the present invention is not limited to this, and can be applied to apparatuses that perform processing using other plasmas. is there. For example, the present invention can be applied to a processing chamber inside a so-called downflow type semiconductor processing apparatus for dry etching as shown in FIG. 6 and a plasma generation chamber inside a CVD apparatus as shown in FIG.

  Further, in each of the above devices, the member covered with nickel is not limited to that shown in the above embodiment, and for example, a heat insulating material, a plasma trap, a dome, an electrode, a susceptor, and a chuck disposed in a place where they can come into contact with radicals Any known member in each of the above devices, such as a focus ring, a lid or a pipe, is included.

  Moreover, as a material containing nickel of this embodiment, it is also possible to use not only nickel alone, but also various nickel alloys, mixtures and compositions with nickel, for example.

  In addition, if each member constituting the semiconductor processing apparatus is coated with nickel or a nickel alloy by porous plating or the like, the surface area of the coated surface is increased and the contact area with the radical is increased. It can be increased further. Moreover, it is good also as what adheres not only to coating | cover but to plate-shaped materials, such as nickel or a nickel alloy, and each member which comprises a semiconductor processing apparatus, for example by means, such as screwing, welding, adhesion | attachment.

It is a block diagram which shows embodiment of this invention. It is an enlarged view showing the example of covering in the embodiment of the present invention. It is an enlarged view which shows the other coating example in embodiment of this invention. It is a comparison table | surface which shows the etching rate in embodiment of this invention. It is a graph which shows the etching rate for every coating material in embodiment of this invention. It is a block diagram which shows other embodiment of this invention. It is a block diagram which shows other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vacuum container 2 ... Processing chamber 2a ... Inner wall 3 ... Stage 3a ... Wide diameter part 3b ... Tapered part 3c ... Small diameter part 4 ... Bottom plate 5 ... Exhaust port 6 ... Exhaust pipe 7 ... Top cover 8 ... Gas inlet 9 ... Gas introduction Tube 10 ... Plasma generation chamber member 11 ... Sealing member 12 ... Microwave waveguide 13 ... Plasma generator 14 ... Plasma generation chamber 15 ... Microwave generator 16 ... Gas storage chamber 17 ... Shower nozzle 18 ... Gas transport tube 19 ... Gas flow path 20 ... Gas control unit W ... Wafer

Claims (4)

In a vacuum processing chamber and a member of a semiconductor processing apparatus for processing a workpiece by exciting a reaction gas introduced into the processing chamber with plasma,
A member for a semiconductor processing apparatus, wherein at least a part is covered with a material containing nickel. A stage for placing the object to be processed is provided in the processing chamber,
The stage includes a mounting surface and a non-mounting surface provided adjacent to the mounting surface,
2. The member for a semiconductor device according to claim 1, wherein at least a part of the non-mounting surface is covered with a material containing nickel.   The member for a semiconductor processing apparatus according to claim 1, wherein the member is provided at a position in contact with radicals in the processing chamber.   A semiconductor processing apparatus comprising the member for a semiconductor processing apparatus according to claim 1.

Images