JP2008010579A - Semiconductor device manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing apparatus having excellent processing quality and durability. <P>SOLUTION: The semiconductor device manufacturing apparatus includes a reaction vessel for introducing a reaction gas, a pair of high-frequency electrode provided within the reaction vessel to generate plasma using a high frequency voltage, a holding member provided within the reaction vessel to hold a processing object, and a heater member for heating the processing object. In this apparatus, a corrosion-proof film is formed at an external front surface of a member provided within the reaction vessel. Accordingly, the semiconductor device manufacturing apparatus can be realized capable of assuring excellent wafer processing quality and durability by suppressing and preventing chemical reaction between the element in the reaction gas and the element in the member structuring material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor device manufacturing apparatus, and in particular, a reaction gas is introduced into a reaction vessel having an evacuation system, and plasma is generated by a high-frequency voltage applied between a wafer stage and a high-frequency electrode. The present invention relates to a semiconductor device manufacturing apparatus that forms and etches a wafer placed on a wafer stage.

  Conventionally, in order to manufacture a semiconductor device, a semiconductor device manufacturing apparatus such as a plasma processing apparatus has been widely used. FIG. 3 shows a schematic configuration of a plasma chemical vapor deposition (hereinafter referred to as plasma CVD) apparatus which is a conventional plasma processing apparatus. As shown in FIG. 3, a conventional plasma processing apparatus is a container for performing plasma processing, a reaction container 101 having a vacuum exhaust system pump 102, and a wafer stage 103 on which a wafer 104 is placed and also serves as a lower electrode. A high-frequency power source 105, a reaction gas introduction system 106 for introducing a reaction gas into the reaction vessel 101, a high-frequency electrode 107 introduced into the reaction vessel, and a gas shower plate 108 also serving as a high-frequency electrode. ing.

  Next, the operation of such a plasma CVD apparatus will be described. First, a wafer 104 made of a silicon material to be deposited is placed on the wafer stage 103. Next, the reaction gas is introduced into the reaction vessel 101 from the reaction gas introduction system 106. The reaction gas introduced into the reaction vessel 101 is dispersed by the gas shower plate 108 and dispersed in the reaction vessel 101.

  Next, when a high-frequency voltage is applied by the high-frequency power source 105, the high-frequency voltage is applied to the reaction gas in the reaction vessel 101 through the high-frequency electrode 107 and the gas shower plate 108 to form plasma, and a film is formed on the wafer 104. When the film to be formed is a silicon oxide film, the reaction gas introduced into the reaction vessel 101 is, for example, tetraethoxysilane and oxygen, or silane and oxygen, nitrous oxide, or the like.

  In such a plasma CVD apparatus, the stage heater is configured as a holder for placing a wafer and an electrode for causing a plasma reaction. The stage heater is placed in an atmosphere inside the apparatus at a temperature of 400 ° C. to 700 ° C. during processing, and is in an environment where the thermal cycle is greatly changed by plasma radiation or the like.

  Since this thermal cycle is repeated, the stage heater is required to have high durability against thermal shock. Further, the stage heater is required to efficiently transfer heat from the heater to the wafer and to have corrosion resistance against a film forming gas, an etching gas, and the like.

  As a base material for such a conventional stage heater, aluminum nitride, anodized aluminum, or an aluminum (A5052) material not subjected to corrosion resistance has been used. In recent years, as the film formation rate increases, the stage heater is severely damaged and has a short life, so that a corrosion resistance and a high durability against thermal shock have been demanded.

As is well known, gases used in the CVD process of the semiconductor manufacturing process are silane (SiH ₄ ), disilane (Si ₂ H ₆ ), germanium fluoride (GeF ₄ ), and hexafluoroethane (C ₂ F). ₆ ), nitrogen trifluoride (NF ₃ ), octafluoropropane (C ₃ F ₈ ), chlorine trifluoride (ClF ₃ ) and the like. When these gases come into contact with the substrate of the stage heater, the fluorine component in the gas reacts with the aluminum component of the substrate of the stage heater to produce a fluoride film. And this fluoride membrane | film | coat peeled from the base material of a stage heater, and there existed a possibility of adhering to the wafer surface, after floating inside the plasma CVD apparatus. Moreover, there was a problem of contamination due to corrosion of the stage heater base material.

  In addition, the plasma CVD apparatus is configured to place a wafer on a stage heater in a vacuum chamber, generate plasma in a low-pressure reaction gas atmosphere, and perform a CVD process. The wafer is heated and cooled. Here, when there is damage on the surface of the stage heater, the uniformity of heating and cooling of the wafer is hindered. The temperature control of the wafer, that is, the uniformity of overheating cooling of the wafer greatly affects the processing quality of the wafer.

  In addition, during the continuous operation of the plasma CVD apparatus, the problem that fluoride (AlF) foreign matter is generated on the surface of the stage heater due to plasma attack and the problem of corrosion due to the reactive gas have a serious adverse effect on the wafer processing quality. Will be affected.

  Below, the stage heater using the conventional base material is demonstrated using FIG. 4 and FIG. FIG. 4 is a schematic cross-sectional view of a chamber of a conventional plasma CVD apparatus. FIG. 5 is an enlarged schematic view showing a portion B in FIG. As shown in FIG. 4, in this plasma CVD apparatus, a lower electrode 113 is fixed on a top surface of a stage heater 112 provided in a vacuum chamber 111 with a fixing screw 114, and the wafer 115 is transferred from the stage heater 112 to the wafer 115. The heat transfer can be made uniform efficiently.

  The wafer 115 is placed on the lower electrode 113 provided on the upper surface of the stage heater 112. Further, the reaction gas as described above is uniformly sprayed on the surface of the wafer 115 through the shower plate 117 from the gas inlet 116 provided above the vacuum chamber 111, and the gas exhaust port 118 is provided by a vacuum pump (not shown). The vacuum chamber 111 is maintained in a low pressure atmosphere. Further, a DC power supply (not shown) is configured to apply a DC voltage with the shower plate 117 as a positive pole and the stage heater 112 as a negative pole.

  As described above, in the plasma CVD apparatus, plasma is generated by applying electric power to the vacuum chamber 111, that is, the reaction gas is decomposed in a state where atoms and molecules are dissociated into ions and electrons, and the material is formed on the wafer at a low temperature. Films can be deposited uniformly.

Further, in the plasma CVD apparatus shown in FIG. 4, a cleaning gas such as octafluoropropane (C ₃ F ₈ ) is introduced into the vacuum chamber 111 at the time of film formation or after film formation, and as shown in FIG. 115, the stage heater 112, the lower electrode 113, the fluoride (AlF-based) foreign matter 119 attached to the vacuum chamber 111, etc.

  However, the plasma attack causes AlF-based foreign matter 119 in the gap between the lower electrode 113 and the stage heater 112 and in the outer surface, which causes problems such as complete cleaning or corrosion. In this case, fluoride (AlF-based) foreign matter 119 is generated in the vicinity of the fixing screw 114, particularly in the gap between the lower electrode 113 and the upper surface of the stage heater 112, as shown in FIG. Since the stage heater 111 is used under conditions of corrosive reaction gas, high temperature atmosphere, and plasma, it is damaged in a short period of time and becomes unusable. It was inevitable.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a semiconductor device manufacturing apparatus excellent in processing quality and durability.

  In order to solve the above-described problems and achieve the object, a semiconductor device manufacturing apparatus according to the present invention includes a reaction vessel for introducing a reaction gas, and a pair of high-frequency waves that are provided in the reaction vessel and generate plasma by a high-frequency voltage. An electrode, a holding member that is provided in the reaction vessel and holds the object to be processed, and a heater member that heats the object to be processed, and a corrosion-resistant film is formed on the outer surface of the member disposed in the reaction vessel It is characterized by that.

  According to this invention, by forming a corrosion-resistant film on the outer surface of the member disposed in the reaction vessel, the chemical reaction between the component in the reaction gas and the component of the component material can be suppressed and prevented. In addition, a semiconductor device manufacturing apparatus excellent in wafer processing quality and durability can be obtained.

  Embodiments of a semiconductor device manufacturing apparatus according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scales between the constituent members may be different for easy understanding.

Embodiment FIG. 1 is a schematic diagram showing a schematic configuration of a plasma CVD apparatus which is a semiconductor device manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged schematic view showing a portion A in FIG. As shown in FIG. 1, a plasma CVD apparatus according to this embodiment includes a vacuum chamber (reaction vessel) 1, a stage heater 2, a lower electrode 3, a fixing screw 4, a high frequency electrode 5, and a gas shower plate. 7.

  The reaction vessel 1 is a vessel for performing plasma processing, and includes a gas introduction port 6 for introducing gas into the vacuum chamber (reaction vessel) 1, and a gas exhaust port 8 for exhausting gas from the vacuum chamber (reaction vessel) 1. And an evacuation pump (not shown).

  Further, in this plasma CVD apparatus, a lower electrode 3 is fixed on a top surface of a stage heater 2 provided in a vacuum chamber (reaction vessel) 1 with a fixing screw 4, and the wafer 9 is transferred from the stage heater 2 to the wafer 9. The heat transfer can be made uniform efficiently. The high frequency electrode 5 and the gas shower plate 7 are fixed by a fixing screw (not shown). Furthermore, a corrosion resistant coating 10 is formed on the outer surface of the stage heater 2 to provide a corrosion resistance treatment.

  Here, the corrosion-resistant film 10 is a film having a high coefficient of thermal expansion and high thermal conductivity and excellent corrosion resistance against reactive gases. Due to the high thermal conductivity, the heat from the stage heater 2 can be efficiently transmitted to the wafer 9 and exhibits excellent durability against thermal shock. Moreover, since the coefficient of thermal expansion of the corrosion-resistant film 10 is larger than the coefficient of thermal expansion of the constituent material of the base material on which the corrosion-resistant film 10 is formed, cracking and peeling due to the thermal expansion are less likely to occur. By being excellent in corrosion resistance with respect to the reaction gas, the chemical reaction between the reaction gas and the stage heater 2 can be suppressed by continuing to be interposed between the reaction gas and the stage heater 2.

  Moreover, it is preferable that the corrosion resistant coating 10 is coated with a material having a larger thermal expansion coefficient than that of the components constituting the stage heater 2. Thus, the corrosion resistance of the stage heater 2 by the corrosion resistant film 10 is not broken by cracking or peeling off of the corrosion resistant film 10 due to thermal expansion of the lower electrode 3.

  Moreover, the film thickness of the corrosion-resistant film | membrane 10 shall be thickness of 0.1 micrometer-500 micrometers, for example. By setting the film thickness of the corrosion-resistant film 10 in such a range, the effects of the present invention described later can be reliably obtained, and the corrosion-resistant film 10 can be efficiently formed.

  In the present embodiment, the corrosion-resistant coating 10 is a film made of a corrosion-resistant material that has a high coefficient of thermal expansion and thermal conductivity and that can suppress, for example, a chemical reaction between the fluorine component and the aluminum component of the stage heater 2. As such a corrosion resistant material, for example, a material such as nickel, chromium, titanium, hastelloy, nickel alloy (for example, Inconel (registered trademark)), diamond, or the like can be used.

  The wafer 9 is placed on the lower electrode 3 provided on the upper surface of the stage heater 2. A reaction gas is uniformly sprinkled on the surface of the wafer 9 through a gas shower plate 7 from a gas inlet 6 provided above the vacuum chamber (reaction vessel) 1 and is exhausted by a vacuum pump (not shown). The air is exhausted from the port 8 and the inside of the vacuum chamber (reaction vessel) 1 is maintained in a low pressure atmosphere.

Here, as the gas used in the CVD process, that is, the gas introduced into the vacuum chamber (reaction vessel) 1, for example, silane (SiH ₄ ), disilane (Si ₂ H ₆ ), germanium fluoride (GeF ₄ ), There are hexafluoroethane (C ₂ F ₆ ), nitrogen trifluoride (NF ₃ ), octafluoropropane (C ₃ F ₈ ), chlorine trifluoride (ClF ₃ ), etc. In the case of a film, for example, tetraethoxysilane and oxygen, or silane and oxygen, nitrous oxide, or the like is used.

  Further, a DC voltage is applied by a DC power supply (high frequency power supply) (not shown) so that the gas shower plate 7 is a positive electrode and the lower electrode 3 is a negative electrode.

  As described above, in the plasma CVD apparatus, plasma is generated by supplying electric power to the vacuum chamber (reaction vessel) 1, that is, the reaction gas is decomposed in a state where atoms and molecules are dissociated into ions and electrons, and the plasma is generated on the wafer. A film can be formed by uniformly depositing a material at a low temperature.

  Next, the operation of the plasma CVD apparatus according to this embodiment configured as described above will be described. First, a wafer 9 made of a silicon material or the like to be deposited is placed on the lower electrode 3. Next, a reaction gas is introduced into the vacuum chamber (reaction vessel) 1 from the gas inlet 6. The reaction gas introduced into the vacuum chamber (reaction vessel) 1 is dispersed by the gas shower plate 7 and dispersed in the vacuum chamber (reaction vessel) 1.

  Next, when a DC voltage is applied by a DC power supply (high frequency power supply) (not shown) with the high frequency electrode 5 as a positive electrode and the lower electrode 3 as a negative electrode, a vacuum chamber (reaction is passed through the high frequency electrode 5 and the lower electrode 3. A high frequency voltage is applied to the reaction gas in the container 1 to form plasma, and a film is formed on the wafer 9. That is, plasma is generated, the reaction gas is decomposed in a state where atoms and molecules are dissociated into ions and electrons, and a material is uniformly deposited on the wafer 9 at a low temperature to form a film.

  In the plasma CVD apparatus according to the present embodiment as described above, the stage heater 2 is warped due to thermal expansion, and a gap and space are generated between the lower electrode 3 and components in the reaction gas, particularly fluorine. Even when the components enter, the corrosion resistant coating 10 is formed on the surface of the stage heater 2, so that the components in the reaction gas (especially fluorine components) and the components of the stage heater 2 (especially aluminum) are reduced. Chemical reaction is suppressed and prevented, and physical connection is maintained. Thereby, the plasma state and the heat conduction state to the wafer are stabilized, so that stable film formation can be performed.

  And since the production | generation of the reaction product (for example, fluoride) by the chemical reaction with the component (especially fluorine component) in reaction gas and the component (especially aluminum) of the constituent material of the stage heater 2 is suppressed and prevented, this reaction It is possible to suppress or prevent the product from floating inside the plasma CVD apparatus and adhering to the wafer surface. Further, contamination in the vacuum chamber (reaction vessel) 1 caused by corrosion of the base material of the stage heater 2 due to components (particularly fluorine components) in the reaction gas is suppressed and prevented.

  Further, since the corrosion-resistant film 10 is formed on the surface of the stage heater 2, the chemical reaction between the components in the reaction gas (especially fluorine components) and the components of the constituent materials of the stage heater 2 (especially aluminum) is suppressed and prevented. Therefore, the occurrence of damage on the surface of the stage heater 2 is suppressed and prevented. As a result, the variation in the uniformity of overheating cooling of the wafer due to the damage of the surface of the stage heater 2, that is, the variation in the processing quality of the wafer 9 is suppressed and prevented.

  Further, since the corrosion-resistant film 10 is formed on the surface of the stage heater 2, the chemical reaction between the components in the reaction gas (especially fluorine components) and the components of the constituent materials of the stage heater 2 (especially aluminum) is suppressed and prevented. Therefore, the usable period can be extended, and the number of replacements of the stage heater 2 due to damage to the stage heater 2 due to chemical reaction with the reaction gas can be reduced. Thereby, the lifetime of the stage heater 2 can be extended and the lifetime of the plasma CVD apparatus can be extended.

In the plasma CVD apparatus according to the present embodiment shown in FIG. 1, a cleaning gas such as octafluoropropane (C ₃ F ₈ ) is supplied into the vacuum chamber (reaction vessel) 1 during or after film formation. Introduced, as shown in FIG. 2, foreign matter and the like attached to the wafer 9, the stage heater 2, the lower electrode 3, and the vacuum chamber (reaction vessel) 1 can be discharged.

  At this time, in the plasma CVD apparatus according to the present embodiment, a reaction product (for example, fluoride) due to a chemical reaction between a component (particularly a fluorine component) in the reaction gas and a component (particularly, aluminum) of the constituent material of the stage heater 2. Is suppressed and prevented, so that cleaning can be easily performed with good cleanliness.

  Further, the corrosion-resistant film 10 does not necessarily have to be applied to the entire surface of the stage heater 2 and may be applied to a part. However, it is preferable that it is applied to the entire outer surface of the stage heater 2. Thereby, the effect of the present invention can be obtained more effectively.

  Further, the corrosion resistant coating 10 is not necessarily applied to the surface of the stage heater 2, and may be applied to the surface of the lower electrode 3. In this case, the chemical reaction between the fluorine component of the reaction gas and the component of the constituent material of the lower electrode 3 can be suppressed.

  The corrosion resistant coating 10 is preferably applied to the surface of the stage heater 2 and the surface of the lower electrode 3. Thereby, the effect of the present invention can be obtained more effectively.

  Further, the corrosion resistant coating 10 is not necessarily applied to the entire surface of the components in the vacuum chamber (reaction vessel) 1. However, it is preferably applied to all the outer surfaces of the components in the vacuum chamber (reaction vessel) 1. Thereby, the effect of the present invention can be obtained more effectively.

  In the above description, the present invention has been described by taking a plasma CVD apparatus as an example. However, the above-described effects of the present invention can also be obtained for a plasma etching apparatus.

  As described above, the semiconductor device manufacturing apparatus according to the present invention is useful when using a reaction process in which a reaction gas is introduced into a reaction vessel and plasma is generated by a high-frequency voltage.

It is a schematic diagram which shows schematic structure of the plasma CVD apparatus which is a semiconductor device manufacturing apparatus concerning embodiment of this invention. It is a schematic diagram which expands and shows the part A in FIG. It is a schematic diagram which shows schematic structure of the conventional plasma CVD apparatus. It is a cross-sectional schematic diagram of the chamber of the conventional plasma CVD apparatus. It is a schematic diagram which expands and shows the part B in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction container 2 Stage heater 3 Lower electrode 4 Fixing screw 5 High frequency electricity 6 Gas introduction port 7 Gas shower plate 8 Gas exhaust port 9 Wafer 10 Corrosion-resistant film 101 Reaction vessel 102 Pump 103 Wafer stage 104 Wafer 105 High frequency power supply 106 Reaction gas introduction system 107 High-frequency electrode 108 Gas shower plate 111 Stage heater 111 Vacuum chamber 112 Stage heater 113 Lower electrode 114 Fixing screw 115 Wafer 116 Gas inlet 117 Shower plate 118 Gas exhaust port 119 Fluoride (AlF system) foreign matter

Claims (9)

A reaction vessel for introducing a reaction gas;
A pair of high-frequency electrodes provided in the reaction vessel to generate plasma by a high-frequency voltage;
A holding member that is provided in the reaction vessel and holds an object to be processed;
A heater member for heating the object to be treated;
With
A corrosion-resistant coating is formed on the outer surface of the member disposed in the reaction vessel;
A semiconductor device manufacturing apparatus. The corrosion-resistant film has a corrosion-resistant film formed on the outer surface of at least one of the pair of high-frequency electrodes;
The semiconductor device manufacturing apparatus according to claim 1. The semiconductor device manufacturing apparatus according to claim 1, wherein the corrosion-resistant film is formed on a part of the high-frequency electrode. The semiconductor device manufacturing apparatus according to claim 1, wherein the corrosion-resistant film is formed on the entire outer surface of the high-frequency electrode. The semiconductor device manufacturing apparatus according to claim 1, wherein the corrosion-resistant film is formed on an outer surface of the heater member. The semiconductor device manufacturing apparatus according to claim 1, wherein the corrosion-resistant film is formed on the entire inner surface of the reaction vessel. 7. The semiconductor device according to claim 1, wherein a coefficient of thermal expansion of the corrosion-resistant film is larger than a coefficient of thermal expansion of a material constituting the base material on which the corrosion-resistant film is formed. Manufacturing equipment. The constituent material of the corrosion-resistant film is at least one selected from the group consisting of nickel, chromium, titanium, hastelloy, nickel alloy and diamond. Semiconductor device manufacturing equipment. The semiconductor device manufacturing apparatus according to claim 1, wherein the corrosion-resistant film has a thickness of 0.1 μm to 500 μm.

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