JPH11111628A - Heating element made of silicon and semiconductor manufacturing apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erosion due to etching gas or plasma and prevent the generation of particles and contamination to prolong life time and enhance strength by making the heating element for heating a semiconductor silicon wafer from a silicon material. SOLUTION: A heating element for heating a semiconductor silicon wafer used in a semiconductor manufacturing apparatus, wherein a semiconductor silicon wafer is disposed at least in a reaction chamber and is treated while being heated, is made of silicon material. Thus, the material of the heating element for heating the semiconductor silicon wafer is identical to that of the silicon wafer. In the manufacture of a discoidal silicon heating element 10, a single-crystal ingot having a desired resistivity is sliced into a disc, and a spiral heater pattern 13 is formed by a groove such that the total resistance is a predetermined resistance, and terminal parts 12 are provided at both ends of the pattern for obtaining the silicon heating element 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating apparatus for heating a semiconductor silicon wafer to be heated, which is used in a CVD apparatus, a sputtering apparatus, an etching apparatus for etching a formed thin film, or the like in a semiconductor device manufacturing process. The present invention relates to a body and a semiconductor manufacturing apparatus provided with the heating element.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a device for a semiconductor, a polysilicon film, a silicon oxide film, a conductor film, a dielectric film and the like are formed on a semiconductor silicon wafer by a CVD apparatus or a sputtering apparatus, or a reverse direction. Techniques for etching these thin films using an etching apparatus are well known. In these apparatuses, it is necessary to keep the silicon wafer to be processed at a desired temperature constant at a desired temperature in order to maintain the quality of the above-mentioned thin film formation and etching. A heater unit having a heating element for heating the wafer is required.

Conventionally, various proposals have been made on the material and system of the heater unit having the heating element. For example, firstly, radiant heating from above the wafer by an infrared lamp can be mentioned. This has the advantage that almost no reduction in the yield of semiconductor devices due to diffusion of impurities has to be taken into account, since the infrared lamp, which is a heating element, does not come into direct contact with the wafer. However, when a single lamp is used to heat the wafer, the uniform state of the wafer is poor, and a plurality of lamps are required to maintain the uniform temperature. A disadvantage is that a lamp is required, and the volume of the lamp as a heating element is very large.

For this improvement, various proposals have been made for heater units employing a resistance heating system from the lower surface of the silicon wafer. With this resistance heating method,
The temperature can be adjusted by adjusting the current and voltage applied to the heating element, and generally has a characteristic that the uniformity is superior to that of the lamp method. However, as the material of the heating element, a metal wire called a so-called nichrome wire or ceramics such as molybdenum disilicide are often used, and these contain a large amount of metal impurities. Diffusion occurs and contaminates the semiconductor wafer to be processed, thereby lowering the yield of the device.

Further, it has been proposed to use carbon or graphite as a heating element so as not to generate metal impurities. However, although there is no concern about metal contamination, there is a risk of causing carbon contamination and the strength is weaker than other heating elements, so a jig such as a support plate is required. As a jig that can be supported without deforming to high temperatures,
After all, ceramics had to be selected, which had the drawback of causing the problem of impurity diffusion.

On the other hand, in the above-mentioned CVD apparatus and sputtering apparatus, there is an apparatus in which a chamber is arranged close to an object to be heated, and a deposit generated by decomposition of a process gas is formed on an inner wall of the chamber. There is also a problem that unless this deposit is removed, particles may be generated.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve such problems, and is hardly affected by etching gas or plasma, does not generate particles and contamination, and has a long life. It is an object of the present invention to provide a heating element having a long and high strength and a semiconductor manufacturing apparatus provided with the heating element.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor manufacturing method in which a semiconductor silicon wafer is disposed at least in a reaction chamber and a process is performed while heating the semiconductor silicon wafer. A heating element for heating a semiconductor silicon wafer used in an apparatus, wherein the heating element is made of silicon.

As described above, when the material of the heating element for heating the semiconductor silicon wafer is made of the same material as the silicon wafer to be processed, particles are generated even when exposed to an etching gas or plasma, and contamination is prevented. It hardly becomes a nation, and the yield in the thin film process of the silicon wafer can be improved.

According to a second aspect of the present invention, the resistance value of silicon is set to be 0.001 to 50 Ω · cm. Here, when the resistance value of silicon is in the range of 0.001 to 50 Ω · cm, the resistance value is appropriate as a heating element and easily available as a material for producing a heating element, which is economically advantageous. is there. Furthermore, if the material is monocrystalline silicon, it is superior to polycrystalline silicon in quality control in terms of impurity content and mechanical strength, which are the doping material added for resistivity adjustment, and is used as a material for heating element production. It is advantageously used.

Next, according to a fourth aspect of the present invention, there is provided a heating apparatus for heating a semiconductor silicon wafer in a semiconductor manufacturing apparatus in which a semiconductor silicon wafer is disposed at least in a reaction chamber and a process is performed while heating the semiconductor silicon wafer. A semiconductor manufacturing apparatus characterized by using a silicon heating element.

When the semiconductor manufacturing apparatus is configured as described above, the material of the heating element for heating the semiconductor silicon wafer to be processed is the same as that of the silicon wafer, so that the particles are not exposed to the etching gas or plasma. Almost no contamination is generated due to generation of impurities or impurities, and the yield of silicon wafers can be improved.

According to a fifth aspect of the present invention, the silicon heating element is arranged on the back side of the surface to be processed of the silicon wafer to be heated. The silicon wafer was disposed on the back side of the surface to be processed via a soaking body.

As described above, when the semiconductor manufacturing apparatus is configured, when the surface to be processed of the silicon wafer faces upward,
Usually, since the processing gas flows from the upper surface facing the wafer, the heat transfer heating performed from the back surface of the wafer is effective for heating the wafer.
Heating power is saved. Further, the provision of the soaking element makes it possible to correct the temperature distribution of the heating element so that the wafer cannot have a temperature distribution or to easily replace the heating element.

In the invention described in claim 7 of the present invention, the silicon heating element is arranged on the surface side of the silicon wafer to be heated, which is the surface to be processed. According to this configuration, the silicon heating element has a smaller volume, can be a compact, high-efficiency radiant heating device as compared with radiant heating by a conventional infrared lamp type lamp.

According to the present invention, a plurality of silicon heating elements are arranged side by side on the front side and / or the rear side, which is the surface to be processed, of the silicon wafer to be heated. In this way, the shape and arrangement of the heating element for uniform heating can be appropriately adapted to a large-diameter silicon wafer, and can be designed more easily than a single heating element. Since the degree of freedom is increased, a compact radiation / heat transfer heating device having high thermal efficiency can be manufactured.

According to a ninth aspect of the present invention, a plurality of silicon heating elements and ceramic plates are alternately joined and arranged so as to surround an outer periphery of a silicon wafer to be heated to form a chamber. I did it. With this configuration, the ceramic plate is an electric insulator and at the same time, a soaking body from the viewpoint of heat conduction, so that the soaking can be performed.
In addition, deposits generated by the reaction and deposited on the wall surface are:
In the chamber of the present invention, since the entire inner wall surface is soaked, there is almost no deposition.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings, but the present invention is not limited thereto. Here, FIGS. 1A and 1B show a main example of a silicon heating element (heater) of the present invention. FIG. 1A shows a disk-shaped heating element, and FIG. 1B shows a rectangular plate-shaped heating element. FIG. 2 is an explanatory view showing an example of a semiconductor device in which the silicon heating element of the present invention is disposed on the back side of a silicon wafer. FIG. 3 is a diagram of a semiconductor device in which the silicon heating element of the present invention is disposed on the front side of the silicon wafer. It is explanatory drawing which shows another example. FIG.
FIG. 5 is an explanatory view showing an example of a semiconductor device in which a plurality of silicon heating elements of the present invention are arranged on the back side and / or the front side of a silicon wafer. FIG. FIG. 3 is an explanatory view showing an example of a semiconductor device provided with a heater chamber manufactured by the above method.

The present inventors have conducted various studies on the prevention of corrosion of a heater used particularly in an apparatus for manufacturing semiconductor devices. As a result, the same material as that of a silicon wafer, which is a main object to be processed, is used for the material of the heater. The inventors have conceived that they can be used, and have completed the present invention.

First, in the present invention, silicon is used as a heating element for heating a semiconductor silicon wafer used in a semiconductor manufacturing apparatus for performing processing while heating the semiconductor silicon wafer at least in a reaction chamber.

As described above, when the material of the heating element for heating the semiconductor silicon wafer is made of the same material as that of the silicon wafer, particles are hardly generated even when exposed to an etching gas or plasma. Therefore, the yield of silicon wafers can be improved. In the case of the conventional heating element material, it contains a large amount of impurities, and the amount of diffusion is extremely large, thus contaminating the object to be processed. It is an excellent heating element with almost no heat.

The resistance value of the silicon heating element was set to 0.001 to 50 Ω · cm, and the type of silicon was set to single crystal silicon. Here, when the resistance value of silicon is in the range of 0.001 to 50 Ω · cm, the value is appropriate as a heating element, and it is easily available as a material for producing a heating element, which is economically advantageous. . Furthermore, if the material is monocrystalline silicon, it is superior to polycrystalline silicon in quality control in terms of impurity content and mechanical strength, which are the doping material added for resistivity adjustment, and is used as a material for heating element production. It is advantageously used.

This silicon can be usually manufactured by the Czochralski method, and according to this method, single crystal silicon can be easily manufactured. When this single crystal silicon is used as a heater material, the material becomes exactly the same as the silicon wafer to be processed, which is the most preferable.

The adjustment of the electrical resistivity of the single crystal silicon is performed by adding a dopant to high-purity polycrystalline silicon called so-called tennine or elevennine used as a raw material. As this doping agent,
Boron (B), phosphorus (P), arsenic (As) and the like are exemplified. To lower the resistivity, increase the amount of dopant added,
In order to increase the resistivity, the amount of the dopant may be reduced.

In the present invention, the resistivity of silicon is 1 milliohm.
・ Cm to 50Ωcm is suitable for use as a heating element. If this resistivity is less than 1 milliohm-cm,
When the addition amount of the dopant becomes extremely large and generates heat as a heater, the dopant is diffused as an impurity,
Silicon wafers may be contaminated. Also 50Ω
If it exceeds cm, the resistance will be too high when used as a heater, and if a high voltage is not applied, no current will flow and no heat will be generated.

Here, the specific shape of the silicon heating element will be described with reference to FIG. 1. (a) shows a disk-shaped silicon heating element 10 which slices a single crystal ingot having a desired resistivity. It is processed into a disk, a spiral-shaped heater pattern 13 is formed by grooves so that the overall resistance becomes a predetermined resistance, and terminal portions 12 are provided at both ends of the pattern to form a silicon heating element 10. .

In this case, it is possible to provide terminals at both ends of the disc-shaped silicon and use the terminals as they are, but it is difficult to control the resistance of the whole heater, and
The current flows at the shortest distance between the terminals, and the heating portion becomes a linear portion connecting the terminals at the shortest, and it is difficult to uniformly generate heat from the entire heating element. Therefore, it is desirable to provide a pattern.

The pattern can be formed simply and according to the purpose by performing groove processing. The spiral shape in (a) is such that the black portion is thick (thickness of the plate of the heating element) and the white portion is thinned by groove processing. Therefore, when a voltage is applied between the terminals, the current flows through a thick portion having a low resistance, and the entire heating element generates heat uniformly. If it is not a disk shape, a zigzag heater pattern 13 can be provided by a rectangular plate-like silicon heating element 11 as shown in FIG.

When it is necessary to make the groove deeper due to the resistance, there may be a problem in strength. In this case, for example, a silicon heating element used as shown in FIG. It can be reinforced by the ceramic plate 29 having the same shape. In addition, the ceramic plate 29 can also act as a heat equalizer 22 described later.

When a silicon compound ceramic such as silicon oxide, silicon nitride, silicon carbide, or the like is used as the material of the ceramic plate, the composition is substantially the same as that of the silicon wafer to be processed, so that it is effective. used. Ceramics such as aluminum nitride and aluminum oxide may be used, but the ceramic surface is coated with silicon, silicon oxide, silicon nitride, silicon carbide, etc., which has higher resistance than the silicon for the heating element so as not to contaminate the workpiece. It is desirable to perform a coating process.

FIG. 1B shows an example of another embodiment of the present invention in which a zigzag heater pattern 13 is formed by a rectangular plate-like silicon heating element 11. Also in this case, the method of forming the heater pattern and the use or non-use of the ceramic plate are the same as in the case of the disc-shaped silicon heating element 10 described above.

Next, a description will be given of a semiconductor device in which the above-mentioned silicon heating element is mounted and used as a heater. This silicon heating element may be arranged to directly heat a semiconductor silicon wafer to be processed, or may be arranged to indirectly heat the semiconductor silicon wafer through a chamber. And radiant heating is possible. Further, by appropriately combining these arrangement methods, the heating temperature, the temperature distribution, the heat cycle, and the like of the object to be processed can be set to the desired ranges.

Here, a dry etching apparatus will be described with reference to FIG. 2 as an example of a semiconductor device using the silicon heating element of the present invention. This dry etching device 2
No. 0 has the silicon heating element 10 and the soaking element 22 arranged on the back side of the processing surface of the silicon wafer 23, while the etching gas is supplied from the gas supply system 26 to the internal gas container 25.
The silicon wafer 23 is rectified by the small-diameter holes of the perforated flow rectifying plate 21, is jetted toward the wafer 23, and is etched by the surface of the silicon wafer 23 heated by the silicon heating element 10 and exhausted from the gas exhaust system 27. Has become.

When the silicon heating element 10 is disposed in direct contact with the back surface of the silicon wafer 23 (in FIG. 2, when there is no heat equalizing element 22), the efficiency of heat conduction and heating is high and the heat loss is small. Therefore, the amount of power can be saved. In the case of the material of the conventional heating element, it contains a large amount of impurities, the amount of diffusion of which is extremely large, and the object to be processed is contaminated. It is an excellent heating element with almost no silicon wafer contamination.

In some cases, a heat equalizer 22 is arranged on the back side of the silicon heat generator 10. The soaking body is preferably one having excellent electrical insulation and heat resistance, and having high thermal conductivity, in order to make the temperature distribution in the heating element surface as uniform as possible, and in consideration of the shape and characteristics of the heating element. In some cases, processing such as providing a distribution in the thickness of the heat equalizing body or providing a groove is performed. The use of high-resistance silicon as the material of the heat equalizer
It is the same material as the heating element, and is most desirable in that there is no contamination and that the thermal conductivity is high. When a silicon compound-based ceramic such as silicon oxide, silicon nitride, silicon carbide, or the like is used, the composition is approximately the same as that of a silicon wafer to be processed, and thus is effectively used. Ceramics such as aluminum nitride and aluminum oxide may be used, but the ceramic surface is coated with silicon, silicon oxide, silicon nitride, silicon carbide, etc., which has higher resistance than the silicon for the heating element so as not to contaminate the workpiece. It is desirable to perform a coating process.

As another embodiment of the present invention, FIG. 3 shows an example in which a rectangular plate-like silicon heating element 11 (see FIG. 1B) is disposed on the surface of the silicon wafer 23 to be processed.
This example is an arrangement method of heating with the same radiant heat as the conventional infrared lamp heating method, but has the advantage that the heating element such as the present invention has a smaller volume and a smaller apparatus than a lamp. I have.

FIG. 4 shows a rectangular plate-like silicon heating element 1.
In the example in which 1 is arranged on both upper and lower surfaces of the wafer 23, a more uniform temperature distribution can be obtained.

FIG. 5 shows that the rectangular plate-like silicon heating elements 11 and the ceramic plates 29 of the present invention are alternately arranged and joined to form a rectangular cylindrical heater chamber 28, and a wafer holder 30 is provided at the center thereof. This is an example of arranging a plurality of silicon wafers 23 set on the wafer. As described above, when the diameter of the object to be processed is increased, a method of surrounding and heating the entire outer periphery of the wafer is advantageous in terms of uniform heating. The reason why the ceramic plate 29 is used is to provide an effect as an insulator, a heat equalizer, a radiant heat reflector, or the like of the heater circuit. In addition, since the chamber itself is heated, the amount of deposits (deposits) adhering to the inner wall of the chamber due to decomposition of the process gas can be reduced, and thermal decomposition of the deposits can be facilitated, thereby reducing particles. It is effective for

The power supply to the heating element according to the present invention may have a structure in which terminal portions 12 are provided at both ends of the heating element circuit, and the connection holes are used to connect the power supply wire with bolts and nuts. At this time, in order to reduce contact resistance, the terminal portion 12 of the heating element may be subjected to plating or sputtering of a conductor, or it is preferable to insert a conductive washer or the like. Unless the bolts and nuts are tightened with a torque wrench so as to tighten the bolts and nuts with a desired torque, the terminal may be damaged when the heating element thermally expands. Therefore, if these bolts and nuts are made of silicon, the coefficients of thermal expansion are exactly the same, and the effect of reducing the thermal stress and reducing the possibility of breakage can be obtained.

[0040]

EXAMPLES The present invention will now be described specifically with reference to examples of the present invention, but the present invention is not limited to these examples. (Example 1) An ingot of single crystal silicon having an outer diameter of 300 mm and a resistivity of 0.1 Ω · cm was prepared. From this, a disk-shaped heating element (see FIG. 1 (a)) subjected to groove processing so as to have an overall resistance of 10Ω was produced by slicing and groove processing. Then, the periphery of the terminal portion was plated with gold. Thereafter, a power supply wire from a power supply was wired to the terminal portion via a bolt and a nut made of silicon. The disk-shaped heating element thus configured was disposed so as to directly contact the lower surface of the silicon wafer having a diameter of 300 mm.

The heating element made of silicon and the silicon wafer thus configured were set in a sputtering apparatus and heated at 200 ° C.
Was used to form a conductive film by sputtering. In this sputter deposition, the temperature can be raised to 200 ° C. in a very short time of 30 seconds, and the temperature difference between the central portion and the outer peripheral portion of the wafer is as small as 4 ° C. The variation in thickness was also within 1%. In addition, no impurities in the object were detected.

(Comparative Example 1, Comparative Example 2) In order to compare with Example 1, an infrared lamp heating type sputtering apparatus (Comparative Example 1) for heating a lamp from above an object to be heated, and a soaking body A sputtering apparatus (Comparative Example 2) using an aluminum oxide plate and using a heating element in which a nichrome wire was arranged in the heating element was prepared, and a sputter film was formed under the same conditions as in Example 1.

As a result, the lamp heating type sputtering apparatus of Comparative Example 1 took 2 minutes to raise the temperature to 200 ° C., and the temperature on the wafer also had a temperature difference of 25 ° C. between the center and the outer periphery. 5% variation in film thickness of deposited conductive film
With very large results. In the sputtering apparatus using the nichrome wire of Comparative Example 2, the temperature difference between the center and the outer periphery of the wafer was as small as 5 ° C., and the variation in the thickness of the formed conductive film was as small as 1%. However, it took 3 minutes to raise the temperature to 200 ° C., and when the object to be treated was analyzed, impurities of Ni and Al were detected.

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same effect. Within the technical scope of

For example, in the above, as an embodiment of the present invention,
Although an example in which the silicon heating element of the present invention is used in a sputtering apparatus for forming a conductive film on a silicon wafer by sputtering has been described, the present invention is not limited to such an example. Forming polysilicon film, silicon oxide film, conductive film, dielectric film, etc.
It goes without saying that the present invention can be used for various semiconductor device manufacturing apparatuses such as a VD apparatus, a sputtering apparatus, and an apparatus for etching each of the above films.

[0046]

According to the present invention, since a silicon heating element made of the same material as a wafer is employed as a heater or a heater chamber for heating a semiconductor silicon wafer as an object to be processed in a semiconductor device manufacturing apparatus, the heat is generated. The diffusion of impurities from the body is eliminated, and no particles or contamination are generated even when exposed to an etching gas or plasma.The damage to the silicon wafer to be processed is caused by a heating element made of another material. It can be much smaller than when used. Also,
Since the heating element is made of silicon, the heating element can be used stably in a semiconductor manufacturing process for a long period of time, thereby enabling a stable operation of the process and preventing a decrease in the yield of a wafer during the reaction treatment.

[Brief description of the drawings]

FIG. 1 is a plan view showing a main example of a silicon heating element of the present invention. (A) Heating element made of disk-shaped silicon, (b) Heating element made of rectangular plate-shaped silicon.

FIG. 2 is an explanatory view of a dry etching apparatus in which a silicon heating element of the present invention is arranged on the back surface of a semiconductor wafer.

FIG. 3 is an explanatory view of a dry etching apparatus in which a silicon heating element of the present invention is disposed above a surface to be processed of a semiconductor wafer.

FIG. 4 is an explanatory view of a dry etching apparatus in which a plurality of silicon heating elements of the present invention are arranged on an upper surface and a rear surface of a processing surface of a semiconductor wafer.

FIG. 5 is an explanatory diagram of a dry etching apparatus provided with a heater chamber formed of a plurality of silicon heating elements and a ceramic plate (heat equalizing element) according to the present invention. (A) Explanatory drawing of the dry etching apparatus which installed the heater chamber, (b) The top view of a heater chamber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Disc-shaped silicon heating element, 11 ... Rectangular plate-shaped silicon heating element, 12 ... Terminal part, 13 ... Heater pattern, 20 ... Dry etching apparatus, 21 ... Perforated rectifying plate, 22 ... Heat equalizer, 23 ... Semiconductor wafer, 24: reaction chamber, 25: internal gas container, 26: gas supply system, 27: gas exhaust system, 28: heater chamber, 29: ceramic plate, 30: wafer holder.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiichi Goto 2-13-1 Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Industry Co., Ltd.

Claims (9)

[Claims] 1. A heating element for heating a semiconductor silicon wafer used in a semiconductor manufacturing apparatus in which a semiconductor silicon wafer is arranged at least in a reaction chamber and is heated and heated, wherein the material of the heating element is silicon. A heating element made of silicon characterized by the following. 2. The method according to claim 1, wherein the resistance value of the silicon is 0.001 to
The heating element made of silicon according to claim 1, wherein the heating element is 50 Ω · cm. 3. The silicon heating element according to claim 1, wherein the silicon is single crystal silicon. 4. A semiconductor manufacturing apparatus for arranging a semiconductor silicon wafer at least in a reaction chamber and performing a process while heating the semiconductor silicon wafer, wherein a silicon heating element is used as a heating element for heating the semiconductor silicon wafer. Semiconductor manufacturing equipment. 5. The semiconductor manufacturing apparatus according to claim 4, wherein the silicon heating element is arranged on the back side of the surface to be processed of the silicon wafer to be heated. 6. The semiconductor manufacturing apparatus according to claim 4, wherein the silicon heating element is disposed on the back side of the surface to be processed of the silicon wafer to be heated via a soaking element. . 7. The semiconductor manufacturing apparatus according to claim 4, wherein the silicon heating element is disposed on the surface side of the silicon wafer as the object to be heated, which is the surface to be processed. 8. A method according to claim 1, wherein the plurality of silicon heating elements are connected to a surface of a silicon wafer to be heated, which is to be processed, and / or
5. The semiconductor manufacturing apparatus according to claim 4, wherein the semiconductor manufacturing apparatus is arranged side by side on the back side. 9. The heater chamber according to claim 4, wherein a plurality of silicon heating elements and ceramic plates are alternately joined and arranged so as to surround the silicon wafer to be heated, thereby forming a heater chamber. Semiconductor manufacturing equipment.