KR20040093518A - Quartz Molded Heater Assembly for Chemical Vapor Deposition - Google Patents

Abstract

PURPOSE: A quartz mold heater assembly for a CVD(Chemical Vapor Deposition) is provided to resist high temperature and to improve corrosion resistance by forming a susceptor using quartz. CONSTITUTION: A wafer contact part(26) is used for loading stably a semiconductor wafer. A quartz part is connected with a lower portion of the wafer contact part. A heat wire(30) is embedded in the quartz part. A cover(25) encloses completely the quartz part except the wafer contact part. The quartz part includes more than two disks. The two disks are connected with each other through a quartz welding portion(35).

Description

Quartz Molded Heater Assembly for Chemical Vapor Deposition {Quartz Molded Heater Assembly for Chemical Vapor Deposition}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater assembly which is essential to be provided inside a CVD reaction chamber in a chemical vapor deposition process which is most frequently used in a semiconductor manufacturing process. In particular, a susceptor for allowing a semiconductor wafer to be seated on top of it and heated is manufactured by using a mold technique of quartz.

The semiconductor manufacturing process consists of hundreds or thousands of complex processes. Among the most frequently used manufacturing processes are an exposure process, a diffusion process, a thin film forming process, and a cleaning process. Many of the steps in the semiconductor manufacturing process are performed at high temperatures to assist the active surface action of the semiconductor wafer. The thin film forming process required in the semiconductor integrated circuit process is performed at different temperatures and different kinds of gas atmospheres depending on the type and thickness of the thin film. Typical examples of the thin film formation process are so-called chemical vapor deposition (CVD). This method is a process in which one or more compound gases are introduced into a reaction chamber prepared for a CVD process to form a thin film on a semiconductor wafer while chemically reacting in a vapor phase with a semiconductor wafer heated to a high temperature. A schematic structure of a conventional CVD apparatus for performing such a CVD process is shown in FIG. 1. The CVD apparatus 10 shown in FIG. 1 includes a reaction chamber 19, a vacuum pump 11 necessary to vacuum the inside of the reaction chamber, and a gas supply port 18 for introducing a reactive gas into the chamber 19. ), An exhaust port 12, and a heater assembly 20. The heater assembly 20 is for heating the semiconductor wafer 13 in order to allow chemical reaction with the reactive gas injected at a high temperature. The heater assembly 20 includes a heat susceptor 15 and a heat susceptor 15, which are made to have a heating wire 14 embedded therein so that the semiconductor wafer 13 is directly seated and heated, and is capable of vertical vertical movement by a predetermined length. It consists of a power supply line 16 for supplying the power supply line 16 and the central support portion 17 for introducing the power supply line 16 into the chamber 19.

The CVD method first vacuums the inside of the chamber 19 using the vacuum pump 11, heats the semiconductor wafer to a high temperature through the heater assembly 20, and then introduces a reactive gas through the gas supply unit 18. Since the reactive gas to be introduced is high vaccum inside the chamber 19, it is easily and quickly scattered evenly in the chamber, and the scattered gas chemically reacts with the surface of the silicon wafer 13 heated to a high temperature so that a thin film is deposited on the wafer. Is formed.

Since the CVD method is performed in a high temperature and reactive (corrosive) gas atmosphere, quartz having heat resistance has been frequently used as an inner tube of the CVD chamber, while a susceptor material of a CVD heater assembly is used. As disclosed in Korean Laid-Open Patent Publication No. 2003-0018290, graphite has been used a lot. According to another prior art, Korean Patent Laid-Open Publication No. 2002-0080954, it can be seen that not only graphite but also SiC (silicon carbide) have been used as susceptor material. come.

However, graphite susceptors have much disadvantages in that particle contamination occurs due to particle generation during in-situ cleaning after the CVD process is finished. It also has the disadvantage that the susceptor is deformed by long-term use, so the life of the susceptor is not so long. . However, the susceptor made of metals has a high thermal conductivity, but it has a disadvantage of causing a lot of corrosion by interacting with a reactive gas which is essential for the CVD process. In the case of disassembly and reassembly for repair, it may be different from the original assembly state, which may cause reliability problems in forming thin films using CVD.

AlN series susceptors, which contain aluminum (Al) and nitride (N) components, are resistant to reactive gases, but are expensive and can be replaced when the power supply line entering the heater assembly is open or the susceptor is broken. There is also a disadvantage that this is impossible for maintenance and repair.

Therefore, the present invention is to provide and develop a susceptor that withstands the disadvantages of such a conventional heater assembly well even at a high temperature of 700 degrees Celsius or more.

Another object of the present invention is to develop a susceptor that is less reactive to various gases used for the CVD thin film formation process, thereby providing a product having better corrosion resistance.

It is still another object of the present invention to provide a corrosion resistant susceptor that can withstand corrosive gases such as CLF ₃ , SF ₆ , NF _3, etc. in a dry cleaning process after the CVD thin film forming process is completed. .

Another main object of the present invention is to provide a heat resistant susceptor that can withstand high temperature CVD processes.

It is another main object of the present invention to provide an economical susceptor that is inexpensive yet easy to maintain and maintain.

1 is a schematic view showing a CVD apparatus.

2 is a cross-sectional view of a susceptor for CVD according to an embodiment of the present invention.

3 is a detailed top view of the susceptor top plate.

4 is a detailed cross-sectional view of the susceptor top plate.

5 is a top view illustrating the arrangement structure of the susceptor middle plate and the hot wire on the middle plate.

6 is a detailed bottom view of the susceptor midplate.

7 is a detailed top view of the lower plate of the susceptor.

8 is a cross-sectional view showing a hollow structure of the susceptor lower plate well.

In order to achieve the object of the present invention, the heater assembly of the present invention comprises: a susceptor cover surrounding the susceptor as part of the susceptor; A wafer contact portion on which the wafer is seated; A quartz top plate coupled to the contact portion from the bottom surface of the contact portion, an insulated middle plate coupled to the contact portion from the bottom surface of the top plate; A quartz lower plate coupled with the middle plate from the lower surface of the middle plate; Heating wire for wafer heating; A fixing pin for pin-coupling the wafer contact portion, the upper plate, the middle plate and the lower plate; The middle plate and the lower plate has a central support for power supply of the heating wire and the support of the heater assembly; It includes a quartz weld for coupling the upper plate and the lower plate.

Preferably, the wafer contact portion is made of AlN material or graphite in consideration of heat transfer and heat dissipation, and the heat wire may be arranged as long as it is arranged between the upper plate and the middle plate. In the arrangement for arranging hot wires, if a groove is formed in the upper plate or the middle plate so that the hot wires are arranged therein, a gap does not occur when the upper plate and the middle plate are joined by the hot wires, so that the coupling between the two does not occur. .

In addition, the main part of the heater assembly is mostly exposed in the vacuum chamber, but the inside of the heater assembly and the inside of the central support are preferably maintained at atmospheric pressure irrespective of the atmosphere of the chamber.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

2 is a view according to an embodiment of the present invention. Referring to this, the heater assembly includes a susceptor cover 25 surrounding the susceptor 15; A wafer contact portion 26 on which the wafer is seated; An upper plate 27 coupled with the contact from the lower surface of the contact portion, and an insulating middle plate 28 coupled with the contact from the lower surface of the upper plate; A lower plate 29 coupled with the middle plate from a lower surface of the middle plate; A heating wire 30 inserted and installed between the upper plate 27 and the middle plate 28 for wafer heating; A wafer support pin (31) for supporting a wafer penetrating the wafer contact portion (26), the upper plate (27), the middle plate (28) and the lower plate (29); Support pin holes 32; A support pin groove 33 which is pinched so that the support pin does not protrude from the wafer contact portion 26; The middle plate 28 and the lower plate 29 has a central support portion 34 coupled to the lower plate for the power supply of the heating wire 30 and the support of the heater assembly; A quartz welding part 35 for coupling the upper plate 27 and the lower plate 29 to each other; An electric wire 36 arranged into a central support part 34 for supplying power to the hot wire 30; The upper and lower coupling grooves 37 and 43 for coupling with the susceptor cover 25 are included.

On the other hand, the heater assembly is capable of some vertical up and down movement by a transfer motor (not shown) mounted to the CVD equipment. When the wafer is placed on the susceptor 15 in the CVD chamber for the CVD process, a transfer motor (not shown) moves the heater assembly down slightly. At this time, the support pin 31 passing through the susceptor 15 does not move. Thus, the wafer is placed by the support pins 31 inserted between the support pin holes 32 to be floating on the susceptor 15. Just before the CVD process begins, the heater assembly is moved to its original position and the wafer rests on the susceptor 15.

The support pin 31 has a wide head shape as shown in FIG. 2 so that the wafer is well seated without shaking. If the head of the support pin 31 is well aligned with the uneven portion of the wafer contact portion 26 when the heater assembly is moved upward for the seating of the wafer, the portion where the wafer and the wafer support portion 26 are in contact with each other is maximized. The efficiency of is good.

The material of the upper plate 27 and the lower plate 29 is made of quartz and welded to each other by a method of quartz welding. The method of quartz welding is generally well known and detailed description is omitted.

The middle plate 28 may be made of any material as long as it is an insulator. Ceramics, BN or magnesium oxide may be used, but quartz is acceptable.

In the structure of the heater assembly shown in the specification of the present invention, the susceptor is made of the upper plate, the middle plate and the lower plate, but the susceptor may be configured by two upper and lower plates, and heat wires may be arranged therebetween.

The wafer contact portion 26 is a portion on which the semiconductor wafer is seated and is made of graphite or AlN material so that the heat generated by the heating wire 30 can be uniformly and quickly transferred to the semiconductor wafer. Ensure that the thickness is produced uniformly and accurately.

The quartz welding part 35 is intended to isolate the inside of the susceptor 15 from the vacuum atmosphere in the CVD chamber by welding the upper plate 27 and the lower plate 29 without a gap. This isolation allows the inside of the susceptor to remain at atmospheric pressure, which increases the life of the susceptor and easily causes thermal conduction of the susceptor.

The susceptor cover 25 surrounds the outer region of the susceptor 15 except for the wafer contact 26. The susceptor cover 25 is divided into a plurality of parts such as 'a', 'b', and a seam such as 'r' and 'd', rather than being formed in one piece. It is good to combine and use. The susceptor cover 25, which consists of several parts, must be welded seamlessly to maintain the atmospheric pressure inside the susceptor 15 of the heater assembly from the vacuum atmosphere in the CVD chamber. In this method of bonding, the above-mentioned parts are glued together and then sintered and pressed together to create a seamless seam without gaps.

The material of the susceptor cover 25 can be used in various ways. If metals are used, the heat conduction efficiency is good, and as described above, the ceramic is weak because it is weak to reactive gas.

Ceramic material is weak to heat and also breaks at high temperature, so another good method for making ceramic cover of heater for high temperature CVD process is to apply quartz to the quartz-molded susceptor. It is a method of coating the outside of the susceptor. It has been found by the inventor's careful experiment that this method is a method of spraying the ceramic powder in the powder state at high speed, which is particularly useful when the ceramic is coated on the outside. According to this method, it has been found through research and experiment that a thin thickness ceramic can be formed to better prevent a ceramic susceptor cover from being broken by high temperature.

3 and 4 are top and cross-sectional views of the upper plate 27, respectively. As shown in these figures, the shape of the top plate must be combined with the wafer contacts to evenly transfer heat to the semiconductor wafer and be able to sufficiently support the wafer, so that the top plate has a round shape and a support pin hole 32 into which the support pin is inserted. There are several, and there are several connection grooves 37 for facilitating the engagement with the susceptor cover in the future. The protrusion 38 at the edge of the top plate is the portion to be joined by the quartz welding technique with the protrusion of the bottom plate which will be described later. This protrusion 38 is intended to maintain a pressure state inside the susceptor at atmospheric pressure and to secure a space for arranging the heating wire. By this internal space, the atmosphere around the hot wire 30 is easily exposed to atmospheric pressure.

5 and 6 are top and bottom views of the middle plate 28. As can be seen from these figures, in the middle plate 28, the heating wire 30 is inserted into the helical hot wire groove of the crushed spiral line on the upper portion of the middle plate. The heating wire 30 is preferably composed of an external heating wire 30-1 and an internal heating wire 30-2, but is not essential for uniform heat transfer to the wafer. The holes 39 shown in the bottom view of FIG. 6 are necessary for the insertion of hot wires or for the connection of hot wires with a TC, ie a thermo couple.

The heating wires 30-1 and 30-2 are required to generate heat due to the resistance component. The material of the hot wire is made of an alloy mixed with elements such as Al, Fe, Cr, and Ni in an appropriate ratio. The content of hot wire is generally well known and detailed description is omitted.

7 and 8 are top and cross-sectional views of the lower plate 29, respectively. The top plate is arranged with several strands of wire and thermocouple 41. The thermocouples 41 rise through the space 42 in the central support 34 and extend to the edge of the lower plate. In this space 42, not only a thermocouple but also an electric wire for supplying electric power to be applied to the heating wire passes. The lower left two strands of wires 44 in FIG. 7 are power lines that will power the outer heating wires 30-1 and FIG. 5. The two stranded wires 45 extending in a 'V' shape on the upper part of FIG. 7 are power lines for applying power to the inner heating wires 30-2 and FIG. 5. The thermocouple 41 is connected to the hot wires 30-1 and 30-2 arranged in the middle plate, respectively, near the edge of the lower plate. The role of the thermocouple 41 is necessary to accurately measure the temperature of the susceptor. The groove 43 shown in FIG. 8 is for facilitating welding of the lower plate and the susceptor cover 25 (FIG. 2).

The lower plate may be configured as a 'T' shaped integral type as shown in Figures 7 and 8, or may be assembled after making the disc portion and the pillar portion separately.

The space 42 inside the central support portion 34 maintains an atmospheric pressure unlike in the CVD chamber. Therefore, the atmospheric pressure is maintained up to the periphery of the heating wire 30 arranged in the upper portion of the middle plate 28 through this space. This characteristic of the present invention is due to the result of the present inventors grasped the advantage that the life of the hot wire is longer in the atmospheric pressure atmosphere than in vacuum.

As described above, the susceptor cover should be coupled without gaps so that the vacuum atmosphere in the chamber does not mix with the atmospheric pressure atmosphere inside the heater assembly. The tightly coupled structure separates the heater assembly interior from the reactive gases introduced for the CVD process in the chamber, thereby preventing the interior of the heater assembly from being quickly corroded by the gas.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

According to the heater assembly of the present invention described above can be easily repaired by quartz welding when the susceptor is broken during use. In addition, the susceptor of the present invention not only withstands a high temperature of 700 degrees Celsius or more in the CVD chamber, but also has low reactivity to various gases used for the CVD thin film formation process, and thus has excellent corrosion resistance.

According to the heater assembly of the present invention described above, after the CVD thin film forming process is finished, it is resistant to corrosive gases, such as CLF ₃ , SF ₆ , NF _3, etc. in the dry cleaning process, and withstands the plasma process well. The availability of the acceptor makes it possible to provide an economical susceptor that is easy to maintain, inexpensive to maintain and has a long lifetime.

According to the heater assembly of the present invention described above, the interior of the susceptor of the present invention can be isolated from the atmosphere of the CVD chamber to maintain the atmospheric pressure state, the life of the susceptor is long, and the thermal conductivity of the susceptor is easy to facilitate the CVD process You can do it more effectively.

Claims (16)

In the quartz mold heater assembly for chemical vapor deposition (Chemical Vapor Deposition) is configured to be able to move up and down by a predetermined length, which can be heated by seating the semiconductor wafer on the upper plane, A wafer contact portion in which the semiconductor wafer is in contact with and seated; A quartz material portion coupled to a lower surface of the wafer contact portion and having a hot wire embedded therein; And a susceptor including a cover covering the quartz material as a whole, except for the wafer contact part. 11. The quartz mold heater assembly of claim 1, wherein the susceptor includes a susceptor. The quartz mold heater assembly of claim 1, wherein the quartz material is formed by fixing two or more circular plates to each other by quartz welding. The quartz mold heater assembly of claim 1, further comprising a support pin penetrating the susceptor. The quartz mold heater assembly of claim 1, wherein the hot wire is arranged in a groove provided in the quartz material part. The quartz mold heater assembly of claim 1, wherein the hot wire is arranged in a groove provided in a part of a plurality of circular plates constituting the quartz material. The quartz mold heater assembly of claim 1, wherein the susceptor is circular. The quartz mold heater assembly of claim 1, wherein the cover is made of a ceramic material. The quartz mold heater assembly of claim 1, wherein the inside of the quartz material and the hot wire are exposed to atmospheric pressure. 8. The quartz mold heater assembly of claim 1, wherein the cover is formed by spraying ceramic. 9. In the quartz mold heater assembly for chemical vapor deposition (Chemical Vapor Deposition) is configured to be able to move up and down by a predetermined length to be seated on the upper plane and heated A wafer contact portion in which the semiconductor wafer is in contact with and seated; A quartz top plate contacting the bottom surface of the wafer contact portion to support the wafer contact portion; An insulating intermediate plate in contact with the lower surface of the upper plate; A quartz lower plate in contact with a lower surface of the middle plate, an edge portion in contact with the upper plate, and a central portion having a hole for supplying power to the heating wire; A cover covering the upper plate, the middle plate, and the lower plate as a whole; Quartz mold heater assembly for chemical vapor deposition (Chemical Vapor Deposition) characterized in that it comprises a susceptor made of. The quartz mold heater assembly of claim 10, wherein at least two of the upper plate, the middle plate, and the lower plate are fixed to each other by quartz welding. 12. The quartz mold heater assembly of claim 10, wherein hot wires are arranged in grooves provided in one of the upper plate and the middle plate. 12. The quartz mold heater assembly of claim 10, wherein hot wires are arranged in grooves provided in each of the upper plate and the middle plate. The quartz mold heater assembly of claim 10, wherein the cover is made of a ceramic material. The quartz mold heater assembly of claim 1, wherein the interior of the susceptor and the hot wire are exposed to atmospheric pressure. The quartz mold heater assembly of claim 1 or 10, wherein the wafer contact portion of the susceptor is made of a material other than quartz.