JP4545896B2 - Heater unit and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heater unit for heating a workpiece used in a film forming apparatus, an etching apparatus or the like in a semiconductor manufacturing process, and a manufacturing method thereof.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a heater unit for heating a wafer by a film forming apparatus such as a CVD apparatus or a PVD apparatus or an etching apparatus is used in a semiconductor manufacturing process, for example. One of the heater units is a ceramic heater. This is a ceramic raw material powder embedded with a thin metal foil of a refractory metal such as tungsten or molybdenum processed into a desired pattern, and sintered, for example, in a disk shape.
[0003]
In the ceramic heater as described above, a heater wire made of metal is embedded in the ceramic heater, which is obtained by processing a thin metal foil of a refractory metal such as tungsten or molybdenum into a required pattern. . In order to obtain an appropriate heat generation amount (resistance value), a general heater wire has a thickness of 20 μm to 50 μm, a width of 2 mm to 5 mm, and a length of 1 m to 3 m. For example, in a two-zone heater for heating an 8-inch wafer, the heater wire has a thickness of 25 μm, a width of 2.5 mm, and a length of about 2 m for the inner and about 2.7 m for the outer. A heater plate (heater unit) is manufactured by solidifying and sintering the ceramic raw material powder so that the heater wire is embedded in the core.
[0004]
[Problems to be solved by the invention]
However, the surface area of the heater wire made of the metal foil as described above is small with respect to the required heat generation amount, and the load density (= heat generation amount / total surface area of the heater wire) tends to be high. Since the heater wire may burn out if the load density becomes excessive, it is better to increase the total surface area of the heater wire. However, since the dimension of the heater wire, that is, the cross-sectional area is limited by the heat generation amount, the above dimensions cannot be changed greatly. .
[0005]
In addition, the positioning when embedding the foil is troublesome, and the heater wire made of foil is thin as described above. Therefore, the heater wire misalignment is the same as the heater wire arrangement pattern temperature. This influences the distribution, thereby greatly degrading the uniformity of the heater unit surface temperature. Furthermore, if the thickness or width of the heater wire (foil) varies, the dimensions themselves are small, so the cross-sectional area of the heater wire (foil) is relatively large, resulting in a large variation in electrical resistance value, and a uniform heater unit surface temperature. Greatly deteriorates the performance.
[0006]
These problems are common as long as not only ceramic heaters but also heater wires made of metal foil are used.
[0007]
On the other hand, the size of the heater wire, that is, the cross-sectional area is limited by the heat generation amount as described above, that is, it is made of a thin and thin foil, so its strength is low. The trouble that the line was cut frequently occurred, and the production yield was lowered. Further, for example, even in a structure in which a pair of disks are bonded and a heater wire is sandwiched between them, there is a problem that the heater wire is broken due to its low strength.
[0008]
The present invention has been made in view of the above-mentioned problems of the prior art. The temperature can be raised quickly at the time of heating, and the heat can be made uniform over the entire surface. In addition, the durability is improved and the production yield is further improved. It is an object of the present invention to provide a heater unit and a manufacturing method thereof.
[0009]
[Means for Solving the Problems]
According to the present invention, the above object is a heater unit having a heater wire embedded therein, wherein the heater wire is made of a metal film formed on a surface of a base member by a film forming means, Covering the base member with a cover member so as to cover the heater wire embeds the heater wire therein, the base member is made of a ceramic sintered body, and the cover member covers the surface of the base member. A heater unit characterized in that it is formed by covering a ceramic raw material powder with solidification, sintering, and sintering , or a heater unit comprising a heater wire embedded therein, wherein the base member is sintered with ceramics. formed by sintered body, formed by film forming means a heater wire made of a metal on a surface of the base member, ceramic so as to cover the surface of the base member Solidifying covered with a scan raw material powder, by sintering, and wherein forming a cover member covering the surface of the base member so as to cover the heater wire, burying the heater wire inside the cover member This is achieved by providing a method for manufacturing a heater unit. In particular, the film forming means may be a spraying means. Since the heater wire formed, especially the heater wire formed by thermal spraying, is porous, its surface area is larger than that of a dense film, and the load density is lowered accordingly. Further, in order to obtain the same cross-sectional area as that of the dense foil, the width and / or thickness can be increased, and high positional accuracy can be obtained by forming a film. Further, since the heater wire is in close contact with the base member after the film formation, the handling is easy without worrying about disconnection.
[0010]
Further, if necessary, electrode wires for different applications from the heater wires are formed on the back surface of the base member by a film forming means, and the base member on which the film is formed is covered with a ceramic raw material powder and hardened. The cover member may be formed by sintering.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0012]
1 and 2 show a schematic structure of a ceramic heater unit 1 according to a first embodiment to which the present invention is applied. The heater unit 1 is a two-zone heater for heating an 8-inch wafer. The outer shape of the heater unit 1 is a disk shape, and the heater wire 2 is embedded inside. The heater wire 2 is made of a sprayed film of one or more refractory metals selected from molybdenum, tungsten, niobium and tantalum. The heater wire 2 is formed by thermal spraying on the surface of a base member 1a made of a ceramic sintered body of aluminum nitride, magnesia or alumina, and is covered with a cover member 1b made of a ceramic sintered body similar to the above.
[0013]
The heater wire 2 has a heater wire inner 3 having a line width of 6.5 mm and a heater wire outer 4 having a line width of 7.5 mm, and is formed in a pattern as shown in FIG. The electrodes 3a and 4a of the heater wire inner 3 and the heater wire outer 4 are connected to the metal terminal 5 embedded in the base member 1a, and the electrodes 3b and 4b are connected to the metal terminal 6 embedded in the base member 1a. The metal terminals 5 and 6 project to the back side of the heater unit 1 and are connected to an external power source (not shown).
[0014]
Here, since the heater wire 2 (the heater wire inner 3 and the heater wire outer 4) is formed by thermal spraying, it is a porous metal film compared to a foil or the like. Therefore, the surface area is large compared to a dense film, and the load density (= calorific value / total surface area of the heater wire) is reduced to 1/3 to 1/4 compared to a film made of foil, for example. The heat is diffused quickly, and it is difficult to burn out when overheated. Moreover, since it is porous, the dimension (thickness or width) with respect to the cross-sectional area for obtaining a desired calorific value can be increased, so even if the thickness or width of the heater wire 2 varies, Since the size itself is large, the influence is reduced, and the uniformity of the temperature of each part of the heater wire 2 is improved, that is, the uniformity of the surface temperature of the heater unit 1 is improved. Further, since it can be widened for the same reason and because the position accuracy is high due to the film formed by thermal spraying, the area of the portion without the heater wire 2 can be reduced as compared with the case of the foil. The uniformity of the surface temperature of 1 is improved.
[0015]
Below, the manufacturing procedure of this heater unit 1 is demonstrated with reference to Fig.3 (a)-FIG.3 (c). First, a ceramic raw material powder of aluminum nitride, magnesia or alumina is hardened into a disk shape and sintered to obtain a base member 1a (FIG. 3A). Next, the heater wire 2 (heater wire inner 3 and heater wire outer 4) is formed on the surface of the base member 1a by thermal spraying in a pattern as shown in FIG. 2 (FIG. 3B). Then, the same ceramic raw material powder as above is covered and hardened so as to cover the heater wire 2, and then the cover member 1b is formed by sintering (FIG. 3 (c)). And the heater unit 1 is obtained by polishing the surface as necessary. This is used for a film forming apparatus or an etching apparatus in the semiconductor manufacturing process.
[0016]
FIG. 4 is a view similar to FIG. 1 showing a schematic structure of the ceramic heater unit 11 in the second embodiment to which the present invention is applied. The heater unit 11 is used in a plasma processing apparatus such as a plasma CVD apparatus. The material, dimensions, film formation pattern, and the like of the heater wire 12 are the same as those in the first embodiment. An RF ground electrode 17 as another electrode line is provided apart from this. The heater wire 12 is formed on the back surface of the base member 11a by thermal spraying, and the RF ground electrode 17 is formed on the surface of the base member 11a by thermal spraying in the same manner as described above. The heater wire 12 and the RF ground electrode 17 are covered with a cover member 11b made of a ceramic sintered body similar to the above.
[0017]
The heater wire 12 and the RF ground electrode 17 are connected to the metal terminals 15 and 16 embedded in the base member 11a, and the RF ground electrode 17 is connected to the metal terminal 18 embedded in the cover member 11b. These metal terminals 15, 16 and 18 project to the back side of the heater unit 11 and are connected to an external power source (not shown) or grounded.
[0018]
Below, the manufacturing procedure of this heater unit 11 is demonstrated with reference to Fig.5 (a)-FIG.5 (c). First, a ceramic raw material powder of aluminum nitride, magnesia or alumina is hardened into a disk shape and sintered to obtain a base member 11a (FIG. 5A). Next, the heater wire 12 is formed in a pattern similar to that shown in FIG. 2 by thermal spraying on the back surface of the base member 11a (FIG. 5B). Further, an RF ground electrode 17 is formed in an appropriate pattern on the surface of the base member 11a by thermal spraying (FIG. 5C). Then, the cover material 11b is formed by covering the heater wire 12 and the RF ground electrode 17, that is, covering the front and back surfaces of the base member 11a with the same ceramic raw material powder, solidified, and sintered (see FIG. 5 (d)), a hole is drilled to attach the metal terminals 15, 16, and 18, and the workpiece mounting surface is polished as necessary to obtain the heater unit 11. This is used for a film forming apparatus or an etching apparatus in the semiconductor manufacturing process.
[0019]
Here, although the RF ground electrode 17 is provided as another electrode line in the present embodiment, the present invention is not limited to this, and this structure can be similarly applied to an embedded electrode such as an electrode for an electrostatic chuck.
[0020]
In each of the above embodiments, the cover member is formed by sintering using the base member as a core. However, these may be fired separately and bonded together so as to sandwich the heater wire. When this is used in a semiconductor processing apparatus, the heater wire is sealed so as not to be exposed from the side surface, or a recess similar to the heater wire pattern is formed on the base member or the cover member so that the heater wire is accommodated in the recess. The base member and the cover member are preferably brought into close contact with each other.
[0021]
In each of the above embodiments, the heater wires and other electrode wires are formed by thermal spraying, but may be formed by other film forming methods such as screen printing, various chemical vapor deposition methods, and physical vapor deposition methods. In that case, it is desirable to form a porous film by appropriately setting the film forming conditions.
[0022]
【The invention's effect】
As apparent from the above description, according to the heater unit and the manufacturing method thereof according to the present invention, a heater wire made of a metal film is formed on the surface of the base member by a film forming means such as spraying, and the heater wire is By covering the base member with a cover member so as to cover it, the heater wire is embedded in the inside, so that the heater wire formed, especially the heater wire formed by thermal spraying, is porous, so it is compared with a dense film As a result, the surface area increases, the load density decreases accordingly, and even if the amount of heat generation becomes excessive, it becomes difficult to burn out, that is, the durability is improved. In addition, since the heater wire is in close contact with the base member, the contact area is increased, the heat transfer efficiency is improved, the thermal stress due to the temperature difference is reduced, and the handling is easy without worrying about physical disconnection. .
[0023]
In addition, since the porous film can have a large dimension (thickness or width) relative to the cross-sectional area for obtaining a desired calorific value, the dimension itself can be obtained even when the thickness or width of the heater wire varies. The effect of this variation is small and the uniformity of the temperature of each part of the heater wire is improved, that is, the uniformity of the surface temperature of the heater unit is improved and the width and / or the cross-sectional area of the dense foil is obtained. Since the thickness can be increased and high positional accuracy can be obtained by forming a film, the area of the area without the heater wire can be reduced compared to the case of foil, which also makes the surface temperature of the heater unit uniform. Will improve.
[0024]
On the other hand, if necessary, an electrode wire for a different purpose from the heater wire is formed on the back surface of the base member by the film forming means, and the base member on which the film is formed is covered with a ceramic raw material powder, solidified, and sintered. Thus, by forming the cover member, there is no fear of positional deviation or disconnection of the heater wire and other electrode wires during firing, and the manufacturing yield is improved.
[Brief description of the drawings]
FIG. 1 is a partial sectional perspective view showing a schematic structure of a ceramic heater unit according to a first embodiment of the present invention.
2 is a plan view showing a heater wire pattern of the heater unit as seen along the line II-II in FIG. 1; FIG.
FIGS. 3A to 3C are cross-sectional views showing a manufacturing procedure of the heater unit of FIG.
FIG. 4 is a partial cross-sectional perspective view showing a schematic structure of a ceramic heater unit according to a second embodiment of the present invention.
5A to 5D are cross-sectional views showing a manufacturing procedure of the heater unit of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ceramic heater unit 1a Base member 1b Cover member 2 Heater wire 3 Heater wire inner 4 Heater wire outer 3a, 3b, 4a, 4b Electrode 5 and 6 Metal terminal 11 Ceramic heater unit 11a Base member 11b Cover member 12 Heater wires 15 and 16 , 18 Metal terminal 17 RF ground electrode

Claims (8)

A heater unit in which a heater wire is embedded,
The heater wire is made of a metal film formed by a film forming means on the surface of the base member,
The heater wire is embedded in the base member by covering the base member so as to cover the heater wire ,
The base member is made of a ceramic sintered body,
A heater unit , wherein the cover member is formed by covering and solidifying ceramic raw material powder so as to cover the surface of the base member, and sintering .   The heater unit according to claim 1, wherein the film forming unit includes a thermal spraying unit. Having an electrode wire for a different use from the heater wire made of a metal film formed on the back surface of the base member by a film forming means;
The electrode wire is embedded in the their by covering the cover member to the back surface of the base member so as to cover the electrode wire,
The said cover member covered on the back surface of the said base member is formed by covering with the ceramic raw material powder so that the back surface of the said base member may be covered, and sintering, It forms. The heater unit according to 2. The heater unit according to claim 3 , wherein the heater wire and the electrode wire are made of one or more metals selected from molybdenum, tungsten, niobium, and tantalum.   The heater unit according to any one of claims 1 to 4, wherein the base member and the cover member are made of a ceramic sintered body selected from aluminum nitride, magnesia, and alumina. A heater unit manufacturing method in which a heater wire is embedded inside,
The base member is formed of a ceramic sintered body,
A heater wire made of metal is formed on the surface of the base member by a film forming means,
Covering and hardening the ceramic raw material powder so as to cover the surface of the base member, and forming a cover member to cover the surface of the base member so as to cover the heater wire by sintering .
A method for manufacturing a heater unit, wherein the heater wire is embedded in the cover member . The method of manufacturing a heater unit according to claim 6 , wherein the heater wire is formed by thermal spraying. An electrode wire for a different use from the heater wire is also formed on the back surface of the base member by a film forming means,
The hardened covered with a ceramic raw material powder so as to cover the back surface of the base member, by sintering, to form a cover member covering the rear surface of the base member to the electrode wire covering the Migihitsuji,
Method of manufacturing a heater unit according to claim 6 or claim 7, characterized in that embedding the electrode wire inside the cover member covering the rear surface of the base member.

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