JP3474406B2 - Silicon heating element and semiconductor manufacturing apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, when a semiconductor device is manufactured, a polysilicon film, a silicon oxide film, a conductor film, a dielectric film, etc. are formed on a semiconductor silicon wafer by a CVD device or a sputtering device, or the reverse. The technique of etching these thin films with an etching device is well known. In these devices, it is necessary to keep the silicon wafer, which is the object to be processed, constant at a desired temperature in order to maintain the quality of the above-mentioned thin film formation and etching. What is needed is a heater unit with a heating element that heats a wafer.

Conventionally, various proposals have been made regarding the material and method of the heater unit provided with this heating element. For example, radiant heating from the upper direction of the wafer by an infrared lamp can be first mentioned. This has an advantage that since the infrared lamp, which is a heating element, does not come into direct contact with the wafer, it is almost unnecessary to consider the decrease in the yield of semiconductor devices due to the diffusion of impurities. However, when heating with one lamp, the soaking state of the wafer is poor, and a plurality of lamps are required to maintain the soaking. Also, since the calorific value per unit area is small and there is a rapid heating, It has a drawback that a lamp is required and the volume of the lamp, which is a heating element, is very large.

In order to improve this, various proposals have been made on a heater unit which employs a resistance heating system from the lower surface of a silicon wafer. With this resistance heating method,
The temperature can be adjusted by adjusting the current and the voltage applied to the heating element, and generally has a characteristic that the soaking property is superior to that of the lamp system. However, as the material of the heating element, a metal wire called so-called nichrome wire or ceramics such as molybdenum disilicide is often used, and since a large amount of metal impurities are contained in these materials, these impurities are not contained at a high temperature. Has a drawback that the semiconductor wafer to be processed is contaminated and the device yield is reduced.

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 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 support up to high temperatures without deformation,
After all, ceramics had to be selected, and there was a drawback that the problem of impurity diffusion would occur.

On the other hand, in the above-mentioned CVD apparatus and sputtering apparatus, there is also an apparatus in which the chamber is arranged in close proximity so as to surround the object to be heated, but the deposits generated by decomposition of the process gas on the inner wall of the chamber There is also a problem that particles are caused unless these deposits are removed.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, is not easily attacked by etching gas or plasma, does not generate particles or contamination, and has a long life. The main object of the present invention is to provide a long and high-strength heating element and a semiconductor manufacturing apparatus provided with this heating element.

[0008]

In order to solve the above problems, the present invention provides a semiconductor silicon wafer for use in a semiconductor manufacturing apparatus in which at least a semiconductor silicon wafer is placed in a reaction chamber and a process is performed while heating the semiconductor silicon wafer. In the heating element to be heated, the material of the heating element is silicon ,
A heating element made of silicon, characterized in that a heating pattern is formed on the heating element.

As described above, by making the material of the heating element for heating the semiconductor silicon wafer the same as that of the silicon wafer which is the object to be processed, particles are generated even when exposed to etching gas or plasma, and contamination is caused. It hardly causes a nation, and the yield in the thin film process of the silicon wafer can be improved.

Then , the resistance value of silicon is set to 0.001
And those of ~50Ω · cm, using the silicon and single crystal silicon. Here, the resistance value of silicon is 0.001 to 5
When it is in the range of 0 Ω · cm, the value is appropriate as a heating element, and it is easy to obtain as a material for producing a heating element, which is economically advantageous. Furthermore, if the material is single crystal silicon, it is superior to polycrystalline silicon in terms of quality control in terms of impurity content and mechanical strength, which is a doped material added for resistivity adjustment. Used to advantage.

Next, according to the invention described in the present invention, in a semiconductor manufacturing apparatus in which at least a semiconductor silicon wafer is disposed in a reaction chamber and processing is performed while heating the silicon wafer, a silicon heating element for heating the semiconductor silicon wafer is used as a heating element. A heater pattern is used on the silicon heating element using a heating element.
It is a semiconductor manufacturing apparatus characterized by being formed .

When the semiconductor manufacturing apparatus is constructed as described above, the material of the heating element for heating the semiconductor silicon wafer, which is the object to be processed, is the same as that of the silicon wafer, so that even if it is exposed to etching gas or plasma, particles are not generated. The yield of silicon wafers can be improved with almost no generation or generation of impurities to cause contamination.

[0013] Then, a silicon heating element, so as to place on the back side of the target surface of the silicon wafer as an object to be heated, a silicon heating element, the back surface of the target surface of the silicon wafer as an object to be heated It was arranged on the side through a soaking body.

When the semiconductor manufacturing apparatus is constructed as described above, when the surface to be processed of the silicon wafer is facing upward,
Normally, the process gas is flowed from the upper part facing each other, so heat transfer heating performed from the backside of the wafer is effective for heating the wafer.
It saves heating power. Further, by providing the soaking body, it becomes possible to correct the temperature distribution of the heating element so that the wafer cannot have the temperature distribution and to easily replace the heating element.

In the invention described in the present invention, the heating element made of silicon is arranged on the surface side which is the surface to be processed of the silicon wafer which is the object to be heated. According to this configuration, the silicon heating element has a smaller volume than the radiant heating by the conventional infrared lamp type lamp, and it is possible to make a radiant heating device that is compact and has high thermal efficiency.

Then , a plurality of silicon heating elements are arranged side by side on the front surface side and / or the back surface side which is the surface to be processed of the silicon wafer which is the object to be heated. In this way, the shape and arrangement of the heating element for uniform heating can be appropriately applied 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 radiant / heat transfer heating device that is compact and has high thermal efficiency can be manufactured.

In the invention described in the present invention , a plurality of silicon heating elements and ceramic plates are alternately bonded and arranged so as to surround the outer periphery of the silicon wafer which is the object to be heated to form a chamber. According to this structure, the ceramic plate serves as an electric insulator and, at the same time, becomes a soaking body from the viewpoint of heat conduction, so that soaking and heating are possible, and deposits generated by the reaction and deposited on the wall surface are generated. In the chamber of the present invention, since the entire inner wall surface is soaked, almost no deposition occurs.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. Here, FIG. 1 is a main example of a silicon heating element (heater) of the present invention, where (a) is a disk-shaped heating element and (b) is 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 arranged on the back side of a silicon wafer, and FIG. 3 is a semiconductor device in which the silicon heating element of the present invention is arranged on the front side of the silicon wafer. It is explanatory drawing which shows another example. Also, 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 front side of a silicon wafer, and FIG. 5 shows the silicon heating elements of the present invention bonded to a ceramic plate. It is explanatory drawing which shows an example of the semiconductor device which provided the heater chamber made by doing.

The inventors of the present invention have made various studies on corrosion prevention of a heater used in a semiconductor device manufacturing apparatus. As a result, the heater is made of the same material as the silicon wafer which is the main object to be processed. The present invention has been completed based on the idea that it can be used.

First, in the present invention, at least the semiconductor silicon wafer is placed in the reaction chamber, and the material of the heating element for heating the semiconductor silicon wafer used in the semiconductor manufacturing apparatus that heats and processes the semiconductor is silicon.

As described above, when the material of the heating element for heating the semiconductor silicon wafer is the same as that of the silicon wafer, particles are hardly generated even if exposed to etching gas or plasma, and contamination is almost generated. Therefore, the yield of silicon wafers can be improved. In the case of the conventional material of the heating element, it contains a large amount of impurities and its diffusion amount becomes very large and contaminates the object to be treated. It is an excellent heating element with almost nothing.

The resistance value of the silicon heating element is 0.001 to 50 Ω · cm, and the type of silicon is single crystal silicon. Here, when the resistance value of silicon is in the range of 0.001 to 50 Ω · cm, it is a suitable value as a heating element, is easily available as a material for producing a heating element, and is economically advantageous. . Furthermore, if the material is single crystal silicon, it is superior to polycrystalline silicon in terms of quality control in terms of impurity content and mechanical strength, which is a doped material added for resistivity adjustment. Used to advantage.

The silicon may be usually manufactured by the Czochralski method, and single crystal silicon is easily manufactured by this method. The use of this single crystal silicon as the heater material is the most preferable because it is the same material as the silicon wafer to be processed.

The electrical resistivity of this single crystal silicon is adjusted by adding a dopant to high-purity polycrystalline silicon called so-called ten-nine or eleven-nine used as a raw material. As this doping agent,
Examples of boron (B), phosphorus (P), arsenic (As), and the like. To lower the resistivity, increase the amount of dopant added,
To increase the resistivity, it is sufficient to reduce the amount of doping agent added.

In the present invention, the resistivity of silicon is 1 milliΩ.
-Cm to 50 Ω-cm is suitable for use as a heating element. If this resistivity is less than 1 milliΩ · cm,
When the amount of doping agent added is significantly increased and heat is generated as a heater, the doping agent diffuses as impurities,
It may contaminate the silicon wafer. 50Ω ・
If it exceeds 10 cm, the resistance becomes too high when it is used as a heater, and unless a high voltage is applied, a current does not flow and heat is not generated.

Here, the specific shape of the silicon heating element will be described with reference to FIG. 1. FIG. 1A shows a disk-shaped silicon heating element 10 in which a single crystal ingot having a desired resistivity is sliced. It is processed into a disk, a spirally wound heater pattern 13 is formed by a groove 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 disk-shaped silicon and use it as a heater as it is, but with that, it is difficult to control the resistance of the entire heater, and
The current flows in the shortest distance between the terminals, and the heat generating portion is a linear portion connecting the terminals in the shortest distance, and it is difficult to uniformly generate heat of the entire heat generating element, so it is desirable to provide a pattern.

The pattern can be easily formed by grooving according to the purpose. The spiral shape of (a) is thick in the black portion (thickness of the plate of the heating element) and thin in the white portion by grooving. Therefore, when a voltage is applied between the terminals, the current flows through the thick portion having low resistance, and heat is uniformly generated in the entire heating element. If it is not a disc shape, a rectangular plate-shaped silicon heating element 11 as shown in FIG. 1B may be provided with a zigzag heater pattern 13.

When it is necessary to make the groove deep due to the resistance, a problem in strength may occur. At that time, for example, the silicon heating element used as shown in FIG. It can be reinforced with the ceramic plate 29 having the same shape. In addition, the ceramic plate 29 can also function as the soaking body 22 described later.

If a silicon compound-based ceramic such as silicon oxide, silicon nitride, or silicon carbide is used as the material of the ceramic plate, the composition is almost the same as that of the silicon wafer to be processed, and it is effective. used. Ceramics such as aluminum nitride and aluminum oxide may be used, but the surface of the ceramics should be covered with silicon, silicon oxide, silicon nitride, silicon carbide, etc., which has a higher resistance than the silicon for the heating element, so as not to contaminate the object to be processed. It is desirable to apply a coating treatment.

FIG. 1B shows another example of the present invention in which a zigzag heater pattern 13 is formed with a rectangular plate-shaped silicon heating element 11. In this case as well, the method of manufacturing the heater pattern and the presence / absence of the use of the ceramic plate are the same as those of the disc-shaped silicon heating element 10.

Next, a semiconductor device in which the silicon heating element is mounted and used as a heater will be described. This silicon heating element is arranged to directly heat the semiconductor silicon wafer which is the object to be processed, or indirectly to heat it through the chamber, and the chamber itself is configured with this silicon heating element. And can be arranged so that radiant heating is possible. Further, these arrangement methods can be appropriately combined to set the heating temperature, temperature distribution, heat cycle, etc. of the object to be treated in a target range.

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

When the silicon heating element 10 is arranged in direct contact with the back surface of the silicon wafer 23 (when there is no soaking body 22 in FIG. 2), the efficiency of heat conduction heating is high and the heat loss is small. Therefore, the electric energy can be saved. In the case of the material of the conventional heating element, it contains a large amount of impurities and its diffusion amount becomes very large and contaminates the object to be processed, but in the present invention, since it is the same material as the object to be processed, there is no diffusion of impurities. It is an excellent heating element with almost no contamination of silicon wafers.

The heat equalizer 22 may be disposed on the back surface side of the silicon heat generator 10. It is preferable that the soaking body is excellent in electrical insulation and heat resistance and has high thermal conductivity, and it is intended to make the temperature distribution in the heating element surface as uniform as possible. Considering the shape and characteristics of the heating element, etc. In some cases, the thickness of the soaking body is distributed, or a groove is formed. High-resistivity silicon is used as the material for the heat equalizer.
It is the most preferable because it is the same material as the heating element, there is no pollution, and the thermal conductivity is high. If a silicon compound-based ceramic such as silicon oxide, silicon nitride, or silicon carbide is used, the composition is almost the same as that of the silicon wafer that is the object to be processed, so that it can be effectively used. Ceramics such as aluminum nitride and aluminum oxide may be used, but the surface of the ceramics should be covered with silicon, silicon oxide, silicon nitride, silicon carbide, etc., which has a higher resistance than the silicon for the heating element, so as not to contaminate the object to be processed. It is desirable to apply a coating treatment.

As another embodiment of the present invention, FIG. 3 shows an example in which the rectangular plate-shaped silicon heating element 11 (see FIG. 1B) is arranged 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 system, but the heating element of the present invention has an advantage that the volume is small and the device can be downsized as compared with the lamp. There is.

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

In FIG. 5, the rectangular plate-shaped silicon heating elements 11 of the present invention and the ceramic plates 29 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 in which a plurality of silicon wafers 23 set in the above are arranged. As the diameter of the object to be treated increases, the method of surrounding and heating the entire outer periphery of the wafer is advantageous in terms of uniform heating. Here, the reason why the ceramics plate 29 is used is to obtain the effect as an insulator, a heat equalizer, a radiant heat reflector, etc. of the heater circuit. In addition, since the chamber itself is heated, the amount of deposit (deposit) that is decomposed by the process gas and adheres to the inner wall of the chamber can be reduced, and the thermal decomposition of the deposit is facilitated, which reduces particles. Is effective for.

Power may be supplied to the heating element of the present invention by providing terminal portions 12 at both ends of the heating element circuit and connecting the feeding wires to the feeding wires with bolts and nuts through the connection holes. At this time, in order to reduce the contact resistance, the terminal portion 12 of the heating element may be plated with a conductor or sputtered, or a conductive washer or the like is preferably inserted. If the bolts and nuts are not tightened with a torque wrench so that they are tightened to a desired torque, the terminals may be damaged when the heating element thermally expands. Therefore, if the bolts and nuts made of silicon are used, the coefficients of thermal expansion become exactly the same, the thermal stress can be reduced, and the risk of damage is almost eliminated.

[0040]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. 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. 1A) grooved so that the overall resistance was 10Ω was manufactured by slicing and grooved. Then, the periphery of this terminal portion was plated with gold. After that, a power supply wire from a power source was wired to the terminal portion via a bolt and a nut made of silicon. The disc-shaped heating element configured as described above was arranged so as to directly contact the lower surface of the silicon wafer having a diameter of 300 mm.

The silicon heating element and the silicon wafer thus constructed are set in a sputtering apparatus, and the temperature is set to 200 ° C.
Then, the conductive film was formed by sputtering. In this sputtering film formation, the temperature can be raised up to 200 ° C. in a very short time of 30 seconds, the temperature difference between the central portion and the outer peripheral portion of the wafer is as small as 4 ° C., and the film of the formed conductive film is formed. The variation in thickness was within 1%. In addition, no impurities were detected in the object to be treated.

Comparative Examples 1 and 2 In order to compare with Example 1, an infrared lamp heating type sputtering device (Comparative Example 1) for heating a lamp from above an object to be heated and a soaking body. A sputtering apparatus (Comparative Example 2) that uses an aluminum oxide plate and uses a heating element in which nichrome wires are arranged in this heat-uniforming body was prepared, and sputtering film formation was performed under the same conditions as in Example 1.

As a result, in the lamp heating type sputtering apparatus of Comparative Example 1, it 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 central part and the outer peripheral part. 5% variation in the film thickness of the formed conductive film
It was a very big result. In addition, in the sputtering apparatus using the nichrome wire of Comparative Example 2, the temperature difference between the central portion and the outer peripheral portion of the wafer was as small as 5 ° C., and the variation in film 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 processed was analyzed, Ni and Al impurities were detected.

The present invention is not limited to the above embodiment. The above-described embodiments are merely examples, and the present invention has substantially the same configuration as the technical idea described in the scope of claims of the present invention, and has any similar effects to the present invention. It is included in the technical scope of.

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

[0046]

According to the present invention, since a silicon heating element made of the same material as a wafer is used as a heater or a heater chamber for heating a semiconductor silicon wafer which is an object to be processed of an apparatus for manufacturing a semiconductor device, heat is generated. Impurities do not diffuse from the body, and particles and contamination do not occur even when exposed to etching gas or plasma, and damage to the silicon wafer that is the object to be processed is caused by heating elements made of other materials. It can be made much smaller than when used. Also,
Since the heating element is made of silicon, it can be used stably in the semiconductor manufacturing process for a long period of time, stable operation of the process becomes possible, and reduction in the yield of the wafer during the reaction treatment can be prevented.

[Brief description of drawings]

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

FIG. 2 is an explanatory view of a dry etching apparatus in which the 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 arranged above a surface to be processed of a semiconductor wafer.

FIG. 4 is an explanatory diagram of a dry etching apparatus in which a plurality of silicon heating elements of the present invention are arranged on the upper and lower surfaces of a semiconductor wafer to be processed.

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

[Explanation of symbols]

10 ... Disc-shaped silicon heating element, 11 ... Rectangular plate-shaped silicon heating element, 12 ... Terminal part, 13 ... heater pattern, 20 ... Dry etching device, 21 ... Porous straightening plate, 22 ... Soaking body, 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.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuyoshi Tamura, Inventor Kazuyoshi Tamura 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd., Institute for Precision Materials (72) Inventor, Keiichi Goto Isobe, Annaka-shi, Gunma 2-13-1 Shin-Etsu Chemical Co., Ltd., Precision Materials Research Laboratory (56) Reference JP-A-57-159022 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/22

Claims (10)

(57) [Claims] 1. A place semiconductor silicon wafer in at least a reaction chamber, in the heat generating element for heating the semiconductor silicon wafers used in the semiconductor manufacturing apparatus to perform the process while heating it, the material of the heat generating body is a silicon, the
A heating element made of silicon, characterized in that a heating pattern is formed on the heating element. 2. The heater pattern is grooved.
It is made into a spiral or zigzag shape by
Silicon-made according to claim 1, characterized in that
Heat body. 3. The resistance value of the silicon is 0.001 to
50Ω · cm, The claim 1 or the contract.
The heating element made of silicon according to claim 2 . 4. The silicon heating element according to any one of claims 1 to 3, wherein the silicon is single crystal silicon. 5. In a semiconductor manufacturing apparatus in which a semiconductor silicon wafer is arranged at least in a reaction chamber and processing is performed while heating the silicon wafer, a silicon heating element is used as a heating element for heating the semiconductor silicon wafer .
A semiconductor manufacturing apparatus characterized in that a heater pattern is formed on a heating element . 6. The semiconductor manufacturing apparatus according to claim 5 , wherein the silicon heating element is arranged on the back surface side of the surface to be processed of the silicon wafer which is the object to be heated. 7. The semiconductor manufacturing apparatus according to claim 5 , wherein the silicon heating element is arranged on the back surface side of the surface to be processed of the silicon wafer which is the object to be heated, with a soaking body interposed therebetween. . 8. The semiconductor manufacturing apparatus according to claim 5 , wherein the silicon heating element is arranged on the surface side which is the surface to be processed of the silicon wafer which is the object to be heated. 9. A plurality of silicon heating elements are provided on a front surface side which is a surface to be processed of a silicon wafer which is an object to be heated and / or
Alternatively, the semiconductor manufacturing apparatus according to claim 5 , wherein the semiconductor manufacturing apparatuses are arranged side by side on the back surface side. 10. A plurality of silicon heating element and the ceramic plate so as to surround the silicon wafer as an object to be heated and bonded alternately arranged, according to claim 5, characterized in that to form the heater chamber Semiconductor manufacturing equipment.