JP2005063990A - Semiconductor manufacturing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide semiconductor manufacturing equipment which is reduced in entire volume, suppresses occurrence of particles, and prevents any damages to a wafer due to falling thereof when mounting and demounting it. <P>SOLUTION: A wafer holder is supported by an electrode for supplying power to an electric circuit formed inside or on the surface of the wafer holder, resulting in eliminating any member for supporting the wafer holder and hence reducing the volume of a container. Since there are a few components, the occurrence of particles is suppressed. The electrode is fixed to a base, and lift pins are set and fixed in the container of the semiconductor manufacturing equipment. By driving the base up and down, the wafer holder is driven up and down, allowing the lift pins to project on the top face of the wafer holder and to retreat under the top face of the wafer holder to mount and demount the wafer, resulting in preventing the falling of the wafer when mounting and demounting it. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor manufacturing apparatus such as plasma CVD, low-pressure CVD, metal CVD, insulating film CVD, ion implantation, etching, low-K film formation, and DEGAS apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a semiconductor manufacturing process, various processes such as a film forming process and an etching process are performed on a semiconductor substrate that is an object to be processed. In a processing apparatus for processing such a semiconductor substrate, a wafer holder (ceramic heater) for holding the semiconductor substrate and heating the semiconductor substrate is used.
[0003]
Such a conventional ceramic heater is disclosed in, for example, Japanese Patent Laid-Open No. 4-78138. As shown in FIG. 2, the ceramic heater disclosed in Japanese Patent Laid-Open No. 4-78138 is a ceramic heater section 1 in which a resistance heating element 2 is embedded, installed in a container 10 and provided with a wafer heating surface. And a convex support portion 7 that is provided on a surface other than the wafer heating surface of the heater portion and forms an airtight seal with the container, and is connected to a resistance heating element, and substantially into the internal space of the container. Electrode 4 taken out of the container so as not to be exposed.
[0004]
Japanese Patent Laid-Open No. 5-9740 proposes a structure in which there is a holding member for holding a ceramic heater, and an electrode for supplying power to the ceramic heater is surrounded by an inorganic insulating material.
[0005]
However, in these structures, since not only the ceramic heater but also the convex support and the holding member are installed in the container, there is a problem that the volume of the container increases. In general, a plurality of lift pins are provided to detach a wafer to be mounted on the wafer holder. In order to detach the wafer, it is necessary to drive the lift pins up and down in synchronization. When the synchronization timing is shifted, there is a problem that the wafer is tilted, dropped and damaged.
[0006]
In addition, there is a problem in that a mechanism for driving a plurality of lift pins in synchronism with each other has to be installed, and the volume of the entire apparatus increases accordingly. Furthermore, there is a problem that fine particles (particles) are generated from components in the container such as a wafer holder and adhere to the wafer surface, thereby contaminating the surface of the wafer as the object to be processed.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 04-078138 [Patent Document 2]
Japanese Patent Laid-Open No. 05-009740
[Problems to be solved by the invention]
The present invention has been made to solve the above problems. That is, an object of the present invention is to omit a member for supporting a ceramic heater, to reduce the volume of a container of a semiconductor manufacturing apparatus and to suppress generation of particles. Also, by omitting the mechanism that drives the lift pins in synchronism with each other up and down, the overall volume of the apparatus can be reduced, and there is no need to synchronize the lift pins, so there is no damage caused by dropping the wafer. An object is to provide a semiconductor manufacturing apparatus.
[0009]
[Means for Solving the Problems]
The semiconductor manufacturing apparatus according to the present invention is characterized in that a wafer holder for a semiconductor manufacturing apparatus is supported by an electrode for supplying power to an electric circuit formed inside or on the surface of the holder. It is preferable that a cylindrical body is disposed so as to surround the electrode.
[0010]
Moreover, it is preferable that the said electrode is being fixed to the base which drives up and down, and the said wafer holding body operate | moves up and down by operating this base up and down. Furthermore, it is preferable that the base and the container are hermetically sealed with a bellows.
[0011]
The wafer holder for a semiconductor manufacturing apparatus is provided with a plurality of through holes through which lift pins are inserted, and the wafer holder is moved up and down by moving the pedestal up and down. It is preferable to be able to detach the wafer on the substrate.
[0012]
The wafer holder is supported by the support body installed on the pedestal and installed in the container of the semiconductor manufacturing apparatus.The lift pins are installed and fixed on the container of the semiconductor manufacturing apparatus, and the pedestal is driven up and down. The wafer holder is driven up and down, and the lift pins protrude from the upper surface (wafer holding surface) of the wafer holder or are buried, whereby the wafer can be detached.
[0013]
Since the plurality of lift pins are fixed to the container, it is easy to align the heights of the tip portions (wafer holding portions) of the plurality of lift pins, and there is no synchronization problem. Further, since a mechanism for driving the lift pins up and down in synchronism is not required, the volume of the entire apparatus can be reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, the wafer holder is supported by the electrode for supplying power to the electric circuit formed in or on the surface of the wafer holder. The wafer holder is formed with one or more electric circuits depending on the purpose, such as a heater circuit for heating, an electrode circuit for generating a high frequency, or an electrode circuit for generating an electron beam.
[0015]
Electrodes are attached to power these electrical circuits from the outside. The number of electrodes varies appropriately depending on the type and function of the electric circuit, and the wafer holder is supported by at least one of the electrodes. The number of electrodes to be supported is preferably 3 or more in consideration of stability.
[0016]
In this way, if the wafer holder is supported by the electrode for supplying power, there is no need to separately install a support for supporting the wafer holder, so the volume of the container of the semiconductor manufacturing apparatus can be reduced. it can. Furthermore, since a support is not required, the number of parts can be reduced as compared with the prior art, and the cost of the entire apparatus can be reduced. Moreover, since the number of parts in a container reduces, generation | occurrence | production of a particle can also be suppressed.
[0017]
Referring to FIG. 1, wafer holder 1 is supported by electrode 4 and installed in a container of a semiconductor manufacturing apparatus. In FIG. 1, the support portion for the electrode 4 is omitted.
Conductors such as the resistance heating element circuit 2 and the high frequency generating circuit 3 are formed on the wafer holder or inside and / or on the surface thereof. Electrodes 4 are attached to power these conductors and support the wafer holder.
[0018]
The shape of the electrode is preferably a rod shape. The cross-sectional shape of the electrode may be a circle, or a polygon such as a quadrangle or a triangle, but when a high voltage is used, it may be a circle to prevent discharge from the electrode to surrounding components. preferable. Further, the sectional area of the electrode is not particularly limited, and may be appropriately selected according to various conditions such as the weight of the wafer holder, the number of electrodes to be supported, or the operating temperature.
[0019]
The material of the electrode is not particularly limited as long as it has a thermal expansion coefficient close to that of the ceramic heater. For example, when the ceramic has a relatively low thermal expansion coefficient such as aluminum nitride, silicon nitride, or silicon carbide, it is preferable to use tungsten, molybdenum, or tantalum for the electrode.
[0020]
In particular, in the case of aluminum nitride, which has been increasingly used for susceptors for semiconductor manufacturing equipment due to its excellent corrosion resistance and the like in recent years, tank stainless steel and molybdenum are particularly preferable.
[0021]
It is also possible to use an iron-nickel-cobalt alloy for the electrode that can match the thermal expansion coefficient of the ceramics. However, the iron-nickel-cobalt alloy has a coefficient of thermal expansion that changes abruptly depending on the temperature.
[0022]
Further, when the ceramic is aluminum oxide (alumina), since the coefficient of thermal expansion is larger than that of the ceramic, it is possible to use various types of iron-nickel-cobalt alloys in addition to the electrode material. .
[0023]
In addition, these electrodes can be subjected to surface treatment as necessary to form a protective film. That is, when protecting an electrode from an oxidizing atmosphere, it is preferable to plate nickel, gold, or silver on the surface of the electrode. It is also possible to plate a plurality of these metals. For example, if the nickel is first plated and then gold or silver is plated thereon, the corrosion resistance is further improved. The type and combination of these platings can be appropriately selected according to the application, that is, the use temperature and the use atmosphere.
[0024]
It is also possible to form a sprayed film on the surface of the electrode. For example, if alumina or mullite is sprayed onto the electrode surface, the corrosion resistance against the gas used such as oxygen can be improved. If aluminum is sprayed in nitrogen, an aluminum nitride film can be formed on the surface of the electrode. Since aluminum nitride is particularly excellent in corrosion resistance, it is particularly effective for improving corrosion resistance.
[0025]
However, when spraying the ceramics as described above, it is necessary to prevent the ceramics from being sprayed on the portion of the electrode that is electrically connected to the conductor formed inside or / and on the surface of the ceramic heater. This is because, since the ceramic is an insulator, if it is sprayed to the electrically connected portion, the electrical connection cannot be obtained. Further, in addition to the ceramics, it is also possible to thermally spray a metal such as nickel, gold or silver.
[0026]
Furthermore, as a method for forming the protective film, various thin film forming methods such as ion plating, CVD, sputtering, and vapor deposition can be employed in addition to plating and thermal spraying. The kind and formation method of a protective film can be properly used according to various uses.
[0027]
Next, a method for electrically connecting a conductor formed in or on the surface of the ceramic heater and the electrode will be described. Referring to FIG. 5, the conductor 2 formed on the ceramic heater 1 is exposed from the ceramic heater. A stable electrical connection can be obtained by directly contacting the electrode and the conductor by subjecting the tip 8 of the electrode 4 to a male screw, subjecting the ceramic heater to a female screw, and screwing the electrode 4 into the ceramic heater 1. Is possible.
[0028]
At this time, the electrical connection becomes more stable when the exposed portion is tapered. Furthermore, if a metal film is formed on the tapered portion by metallization, the contact area of the electrical connection portion is increased, and the reliability of electrical connection is improved. As another method, the contact area can be similarly increased by inserting a metal foil into the tapered portion. The metal foil to be inserted may be made of the same material as that of the electrode, but for the purpose of increasing the contact area and reducing the contact resistance, a soft metal such as gold, silver, copper or aluminum is preferable.
[0029]
In addition, as shown in FIG. 6, the electrode 4 can be brazed to the conductor 2 using a brazing material 9. As the brazing material, silver brazing or active metal brazing can be used.
In this way, the electrode and the conductor are electrically connected, but the connection portion is inferior in corrosion resistance. Therefore, as shown in FIG. 5, the connection portion is sealed with glass 21 using a ceramic member 20. It is preferable. If the connection portion is sealed in this manner, oxygen and reaction gas do not enter the connection portion, so that the reliability of the connection portion is further improved.
[0030]
Moreover, as shown in FIG. 3, it is also possible to attach the cylindrical body 6 so that the electrode 4 may be surrounded. The cylindrical body 6 has a role of preventing a short circuit between a plurality of electrodes, and is preferably attached in order to improve reliability. In particular, when the distance between the electrodes is short and the potential difference is large, it is preferable to attach a cylindrical body. The cylindrical body 6 is preferably an insulating material having heat resistance.
[0031]
Furthermore, it is possible to isolate the internal space of the cylindrical body from the atmosphere in the container of the semiconductor manufacturing apparatus. If isolated, the short circuit between the electrodes is more reliably prevented, and the electrodes are not exposed to corrosive gas at all, so that the durability of the electrodes is further improved. As a method of isolating, for example, there is a method in which a cylindrical body is joined to a ceramic heater with glass or active metal brazing, and the cylindrical body and the container are hermetically sealed with an O-ring. Since the cylindrical body is joined to the ceramic heater, it is preferably the same material as that of the ceramic heater or a material having a difference in thermal expansion coefficient of 5 × 10 ⁻⁶ / ° C. or less.
[0032]
If the cylindrical body is attached in this manner, it is preferable that discharge does not occur between the electrodes or between the electrode and the container even when used under a high voltage. Further, when the container is a conductive material such as a metal, a short circuit can be prevented more reliably by inserting an insulator such as ceramics into the contact portion between the O-ring and the container.
[0033]
The wafer holder used in the present invention is provided with a plurality of through holes through which lift pins are inserted, and the plurality of lift pins are installed in the container in accordance with the through holes.
This lift pin is fixedly installed on the container. For this reason, it is not necessary to provide a mechanism that drives the lift pins up and down in synchronization. For this reason, it is possible to reduce the size as compared with the conventional apparatus having such a mechanism.
[0034]
The tip positions of a plurality of lift pins fixedly installed in the container, that is, the surface in contact with the wafer must be the same plane. Otherwise, the wafer may tilt and fall when it is held. However, since the lift pins are not driven up and down as in the prior art and are fixed in the container, the adjustment of the tip position is much easier than in the prior art.
[0035]
It is preferable that the flatness of the virtual plane formed by the tip surfaces of the plurality of lift pins is 0.5 mm or less. If the flatness exceeds 0.5 mm, the possibility of the wafer falling increases.
[0036]
Referring to FIG. 4, a plurality of lift pins 5 are fixedly installed in container 10. Wafer holder 1 is supported by electrode 4 fixed to pedestal 15. By driving the pedestal up and down, the wafer holder 1 is driven up and down, and the wrist pins protrude from the upper surface (wafer holding surface) of the wafer holder or are buried so that the wafer can be detached.
[0037]
The pedestal is not particularly limited in material as long as it is electrically insulated from the electrodes. And in order to implement | achieve the smooth up-and-down movement of this base, and to interrupt | block the atmosphere inside and outside a container, it is desirable that the said base and a container are airtightly sealed with the bellows. The material of the bellows is not particularly limited, but nickel, stainless steel, aluminum and the like are desirable from the viewpoint of heat resistance and corrosion resistance.
[0038]
The space between the pedestal and the bellows and between the bellows and the container is hermetically sealed. However, there is no particular limitation on the method, and a known method such as brazing or sealing using an O-ring can be used.
[0039]
The material of the wafer holder of the present invention is not particularly limited as long as it is an insulating ceramic, but aluminum nitride (AlN) having high thermal conductivity and excellent corrosion resistance is preferable. Below, the manufacturing method of the wafer holder of this invention is explained in full detail in the case of AlN.
[0040]
The raw material powder of AlN preferably has a specific surface area of 2.0 to 5.0 m ² / g.
When the specific surface area is less than 2.0 m ² / g, the sinterability of aluminum nitride is lowered. On the other hand, if it exceeds 5.0 m ² / g, the aggregation of the powder becomes very strong, so that handling becomes difficult. Furthermore, the amount of oxygen contained in the raw material powder is preferably 2 wt% or less. When the amount of oxygen exceeds 2 wt%, the thermal conductivity of the sintered body decreases. The amount of metal impurities other than aluminum contained in the raw material powder is preferably 2000 ppm or less. When the amount of metal impurities exceeds this range, the thermal conductivity of the sintered body decreases. In particular, group IV elements such as Si and iron group elements such as Fe as metal impurities have a high effect of reducing the thermal conductivity of the sintered body, and therefore the content is preferably 500 ppm or less.
[0041]
Since AlN is a hardly sinterable material, it is preferable to add a sintering aid to the AlN raw material powder. The sintering aid to be added is preferably a rare earth element compound. The rare earth element compound reacts with the aluminum oxide or aluminum oxynitride existing on the surface of the aluminum nitride powder particles during the sintering to promote the densification of the aluminum nitride and the thermal conductivity of the aluminum nitride sintered body. Therefore, the thermal conductivity of the aluminum nitride sintered body can be improved.
[0042]
The rare earth element compound is preferably an yttrium compound that is particularly effective in removing oxygen. The addition amount is preferably 0.01 to 5 wt%. If it is less than 0.01 wt%, it is difficult to obtain a dense sintered body, and the thermal conductivity of the sintered body decreases. If it exceeds 5 wt%, a sintering aid exists at the grain boundaries of the aluminum nitride sintered body. Therefore, when used in a corrosive atmosphere, the sintering aid present at the grain boundaries is etched. , Cause degranulation and particles. Furthermore, the amount of the sintering aid added is preferably 1 wt% or less. If it is 1 wt% or less, the sintering aid is not present at the triple point of the grain boundary, so that the corrosion resistance is improved.
[0043]
As the rare earth element compound, an oxide, nitride, fluoride, stearic acid compound, or the like can be used. Of these, oxides are preferable because they are inexpensive and readily available. In addition, since the stearic acid compound has a high affinity with an organic solvent, when the aluminum nitride raw material powder and the sintering aid are mixed with the organic solvent, the mixing property is particularly preferable.
[0044]
Next, a predetermined amount of a solvent, a binder and, if necessary, a dispersant and a glaze are added to and mixed with the aluminum nitride raw material powder and the sintering aid powder. As the mixing method, ball mill mixing, ultrasonic mixing, or the like is possible. A raw material slurry can be obtained by such mixing.
[0045]
An aluminum nitride sintered body can be obtained by molding and sintering the obtained slurry. There are two types of methods, a cofire method and a post metallization method.
[0046]
First, the post metallization method will be described. Granules are prepared from the slurry by a technique such as spray drying. The granules are inserted into a predetermined mold and press-molded. At this time, the pressing pressure is desirably 0.1 t / cm ² or more. When the pressure is less than 0.1 t / cm ² , the strength of the molded body is often not obtained sufficiently, and is easily damaged by handling.
[0047]
Although the density of a molded object changes with content of a binder, and the addition amount of a sintering auxiliary agent, it is preferable that it is 1.5 g / cm < ³ > or more. If it is less than 1.5 g / cm ³ , the distance between the raw material powder particles becomes relatively large, so that sintering does not proceed easily. Moreover, it is preferable that a molded object density is 2.5 g / cm < ³ > or less. If it exceeds 2.5 g / cm ³ , it will be difficult to sufficiently remove the binder in the molded body by the degreasing process in the next step. For this reason, it becomes difficult to obtain a dense sintered body as described above.
[0048]
Next, the molded body is heated in a non-oxidizing atmosphere to perform a degreasing treatment. When the degreasing treatment is performed in an oxidizing atmosphere such as the air, the surface of the AlN powder is oxidized, so that the thermal conductivity of the sintered body is lowered. As the non-oxidizing atmosphere gas, nitrogen or argon is preferable. The heating temperature for the degreasing treatment is preferably 500 ° C. or higher and 1000 ° C. or lower. When the temperature is less than 500 ° C., the binder cannot be sufficiently removed, and therefore, carbon remains excessively in the molded body after the degreasing treatment, so that sintering in the subsequent sintering step is hindered. Further, at a temperature exceeding 1000 ° C., the amount of remaining carbon becomes too small, so that the ability to remove oxygen from the oxide film present on the surface of the AlN powder is lowered, and the thermal conductivity of the sintered body is lowered.
[0049]
Moreover, it is preferable that the carbon content which remains in the molded object after a degreasing process is 1.0 wt% or less. If carbon exceeding 1.0 wt% remains, sintering is inhibited, and a dense sintered body cannot be obtained.
[0050]
Next, sintering is performed. Sintering is performed at a temperature of 1700 to 2000 ° C. in a non-oxidizing atmosphere such as nitrogen or argon. At this time, it is preferable that the moisture contained in the atmosphere gas such as nitrogen used is −30 ° C. or less in terms of dew point. In the case of containing more moisture than this, AlN reacts with moisture in the atmospheric gas during sintering to form oxynitrides, which may reduce the thermal conductivity. Moreover, it is preferable that the oxygen amount in atmospheric gas is 0.001 vol% or less. If the amount of oxygen is large, the surface of AlN may be oxidized and the thermal conductivity may be reduced.
[0051]
Furthermore, a boron nitride (BN) compact is suitable for the jig used during sintering. This BN compact has sufficient heat resistance to the sintering temperature, and its surface has solid lubricity, so the friction between the jig and the compact when the compact shrinks during sintering. Therefore, a sintered body with less distortion can be obtained.
[0052]
The obtained sintered body is processed as necessary. When screen-printing the conductive paste in the next step, the surface roughness of the sintered body is preferably 5 μm or less in terms of Ra. If the thickness exceeds 5 μm, defects such as pattern bleeding and pinholes tend to occur when a circuit is formed by screen printing. The surface roughness Ra is more preferably 1 μm or less.
[0053]
When polishing the above surface roughness, it is natural to screen print on both sides of the sintered body, but even when screen printing is performed only on one side, the surface opposite to the screen printed side is also polished. It is better to apply. When only the surface to be screen printed is polished, the sintered body is supported by the surface that is not polished during screen printing. At this time, there may be protrusions and foreign matters on the surface that has not been polished, so that the fixing of the sintered body becomes unstable, and the circuit pattern may not be drawn well by screen printing.
[0054]
At this time, the parallelism of both processed surfaces is preferably 0.5 mm or less. When the parallelism exceeds 0.5 mm, the thickness of the conductive paste may vary greatly during screen printing. The parallelism is particularly preferably 0.1 mm or less. Furthermore, the flatness of the screen printing surface is preferably 0.5 mm or less. Even in the case of flatness exceeding 0.5 mm, the variation in the thickness of the conductive paste may increase. A flatness of 0.1 mm or less is particularly suitable.
[0055]
A conductive paste is applied by screen printing to the polished sintered body to form an electric circuit. The conductive paste can be obtained by mixing metal powder, oxide powder as necessary, binder and solvent. The metal powder is preferably tungsten (W), molybdenum (Mo) or tantalum (Ta) from the viewpoint of matching the thermal expansion coefficient with ceramics.
[0056]
In order to increase the adhesion strength with AlN, an oxide powder can also be added. The oxide powder is preferably an oxide of a IIa group element or a IIIa group element, Al ₂ O ₃ , SiO ₂ or the like. In particular, yttrium oxide is preferable because it has very good wettability to AlN. The addition amount of these oxides is preferably 0.1 to 30 wt%. When the content is less than 0.1 wt%, the adhesion strength between the metal layer, which is the formed electric circuit, and AlN is lowered. Moreover, when it exceeds 30 wt%, the electrical resistance value of the metal layer which is an electric circuit will become high.
[0057]
Moreover, as a metal powder, it is good also considering 1 or more types chosen from silver, palladium, and platinum as a main component. Specifically, an Ag-based metal such as Ag—Pd or Ag—Pt is preferable. In this case, the resistance value can be controlled by the content of palladium (Pd) or platinum (Pt). In addition, the same oxide powder as in the case of tungsten or the like can be added. Also in this case, the amount of oxide added is preferably 1 wt% or more and 30 wt% or less.
[0058]
These powders are mixed, a binder and a solvent are added to prepare a paste, and a predetermined circuit pattern is formed by screen printing. At this time, the thickness of the conductive paste is preferably 5 μm or more and 100 μm or less as a thickness after drying. When the thickness is less than 5 μm, the electrical resistance value becomes too high and the adhesion strength also decreases. Moreover, also when exceeding 100 micrometers, adhesive strength falls.
[0059]
Moreover, when the circuit pattern to be formed is a heater circuit (resistance heating element circuit), the pattern interval is preferably 0.1 mm or more. If the interval is less than 0.1 mm, when a current is passed through the resistance heating element, a leakage current is generated depending on the applied voltage and temperature, resulting in a short circuit. In particular, when used at a temperature of 500 ° C. or higher, the pattern interval is preferably 1 mm or more, more preferably 3 mm or more.
[0060]
Next, the conductive paste is degreased and fired. Degreasing is performed in a non-oxidizing atmosphere such as nitrogen or argon. The degreasing temperature is preferably 500 ° C. or higher. If the temperature is less than 500 ° C., the binder in the conductive paste is not sufficiently removed, and carbon remains in the metal layer, and metal carbide is formed when baked, so that the electrical resistance value of the metal layer becomes high.
[0061]
Firing is preferably performed at a temperature of 1500 ° C. or higher in the case of W, Mo, or Ta in a non-oxidizing atmosphere such as nitrogen or argon. When the temperature is less than 1500 ° C., the particle growth of the metal powder in the conductive paste does not proceed, so that the electric resistance value of the fired metal layer becomes too high. The firing temperature should not exceed the sintering temperature of the ceramic. When the conductive paste is fired at a temperature exceeding the sintering temperature of the ceramic, the sintering aid contained in the ceramic begins to evaporate, and further, the grain growth of the metal powder in the conductive paste is promoted, and the ceramic and the metal layer. The adhesion strength of the is reduced.
[0062]
In the case of an Ag-based metal, the firing temperature is preferably 700 ° C to 1000 ° C. The firing atmosphere can be performed in air or nitrogen. In this case, the degreasing process can be omitted.
[0063]
Next, in order to ensure the insulation of the formed metal layer, an insulating coat can be formed on the metal layer. The material of the insulating coat is preferably the same material as the ceramic on which the metal layer is formed. If the materials of the ceramic and the insulating coat are significantly different, problems such as warping after sintering occur due to the difference in thermal expansion coefficient. For example, in the case of AlN, a predetermined amount of Group IIa element or Group IIIa element oxide or carbonate is added to the AlN powder as a sintering aid, mixed, and a binder or solvent is added thereto, and the paste is used as a paste. It can apply | coat on the said metal layer by screen printing.
[0064]
At this time, the amount of the sintering aid to be added is preferably 0.01 wt% or more.
If it is less than 0.01 wt%, the insulating coating will not be densified, and it will be difficult to ensure the insulating properties of the metal layer. Moreover, it is preferable that the amount of sintering aid does not exceed 20 wt%. If it exceeds 20 wt%, an excessive sintering aid penetrates into the metal layer, and the electrical resistance value of the metal layer may change. Although there is no restriction | limiting in particular in the thickness to apply | coat, It is preferable that it is 5 micrometers or more. This is because if it is less than 5 μm, it is difficult to ensure insulation.
[0065]
Next, a ceramic substrate can be further laminated as required. Lamination is preferably performed via a bonding agent. The bonding agent is obtained by adding a IIa group element compound or a group IIIa element compound and a binder or a solvent to aluminum oxide powder or aluminum nitride powder, and applying the paste to the bonding surface by a method such as screen printing. Although there is no restriction | limiting in particular in the thickness of the bonding agent to apply | coat, it is preferable that it is 5 micrometers or more. When the thickness is less than 5 μm, bonding defects such as pinholes and bonding unevenness easily occur in the bonding layer.
[0066]
The ceramic substrate coated with the bonding agent is degreased at a temperature of 500 ° C. or higher in a non-oxidizing atmosphere. Thereafter, the ceramic substrates to be stacked are superposed, a predetermined load is applied, and the ceramic substrates are bonded together by heating in a non-oxidizing atmosphere. The load is preferably 5 kPa (0.05 kg / cm ² ) or more. When the load is less than 5 kPa, sufficient bonding strength cannot be obtained, or the above-described bonding defect is likely to occur.
[0067]
The heating temperature for bonding is not particularly limited as long as the ceramic substrates are sufficiently adhered to each other through the bonding layer, but is preferably 1500 ° C. or higher. If it is less than 1500 degreeC, sufficient joint strength is hard to be obtained and it will be easy to produce a joint defect. Nitrogen or argon is preferably used for the non-oxidizing atmosphere during the degreasing and bonding.
[0068]
As described above, a ceramic laminated sintered body serving as a wafer holder can be obtained. For example, if the electric circuit is a heater circuit without using a conductive paste, for example, a molybdenum wire (coil), an electrostatic adsorption electrode or an RF electrode, a mesh of molybdenum or tungsten (network) It is also possible to use.
[0069]
In this case, the molybdenum coil and mesh are incorporated in the AlN raw material powder, and can be manufactured by a hot press method. The hot press temperature and atmosphere may be the same as the AlN sintering temperature and atmosphere, but the hot press pressure is preferably 1 MPa (10 kg / cm ² ) or more. If the pressure is less than 1 MPa, a gap may be generated between the molybdenum coil or mesh and AlN, and the performance of the wafer holder may not be achieved.
[0070]
Next, the cofire method will be described. The raw material slurry described above is formed into a sheet by a doctor blade method. Although there is no restriction | limiting in particular regarding sheet shaping | molding, As for the thickness of a sheet | seat, 3 mm or less is preferable after drying. If the thickness of the sheet exceeds 3 mm, the amount of drying shrinkage of the slurry increases, so that the probability of cracking in the sheet increases.
[0071]
A metal layer to be an electric circuit having a predetermined shape is formed on the above-described sheet by applying a conductive paste by a technique such as screen printing. The same conductive paste as that described in the post metallization method can be used. However, in the cofire method, there is no problem even if the oxide powder is not added to the conductive paste.
[0072]
Next, the sheet on which the circuit is formed and the sheet on which the circuit is not formed are stacked. In the laminating method, each sheet is set at a predetermined position and overlapped. At this time, a solvent is applied between the sheets as necessary. In the state of being overlaid, heat as necessary. When heating, it is preferable that heating temperature is 150 degrees C or less. When heated to a temperature exceeding this, the laminated sheets are greatly deformed. Then, the stacked sheets are integrated by applying pressure. The applied pressure is preferably in the range of 1 to 100 MPa. If the pressure is less than 1 MPa, the sheets may not be sufficiently integrated and may peel during the subsequent steps. Further, when a pressure exceeding 100 MPa is applied, the deformation amount of the sheet becomes too large.
[0073]
This laminated body is degreased and sintered in the same manner as the above-described post metallization method. The degreasing treatment and sintering temperature, the amount of carbon, etc. are the same as in the post metallization method. When printing the conductive paste on a sheet as described above, a wafer holding body having a plurality of electric circuits can be easily obtained by printing a heater circuit, an electrostatic adsorption electrode, etc. on each of the sheets and laminating them. It is also possible to create it. In this way, a ceramic laminated sintered body serving as a wafer holder can be obtained.
[0074]
The obtained ceramic laminated sintered body is processed as necessary. Usually, in the sintered state, the accuracy required for a semiconductor manufacturing apparatus is often not reached. As for the processing accuracy, for example, the flatness of the wafer mounting surface is preferably 0.5 mm or less, more preferably 0.1 mm or less. When the flatness exceeds 0.5 mm, a gap is likely to be formed between the wafer and the wafer holder, and the heat of the wafer holder is not transmitted uniformly to the wafer, and the temperature unevenness of the wafer is likely to occur.
[0075]
The surface roughness of the wafer mounting surface is preferably 5 μm or less in terms of Ra. When Ra exceeds 5 μm, AlN degranulation may increase due to friction between the wafer holder and the wafer. At this time, the shed particles become particles, which adversely affects processing such as film formation and etching on the wafer. Further, the surface roughness is preferably 1 μm or less in terms of Ra.
[0076]
As described above, the wafer holder body can be manufactured. Next, an electrode is attached to the wafer holder. The attachment can be performed by the method described above. In this way, a wafer holder for a semiconductor manufacturing apparatus can be manufactured. By assembling the wafer holder in the semiconductor manufacturing apparatus, the semiconductor manufacturing apparatus of the present invention can be obtained.
[0077]
【Example】
Example 1
Mix 99.5 parts by weight of aluminum nitride powder and 0.5 parts by weight of Y ₂ O ₃ powder, add polyvinyl butyral as a binder and dibutyl phthalate as a solvent, add 10 parts by weight and 5 parts by weight, respectively. The slurry was prepared by mixing for 24 hours. The aluminum nitride powder used had an average particle size of 0.6 μm and a specific surface area of 3.4 m ² / g. This slurry was granulated with a spray dryer, and the granule was inserted into a mold and molded to prepare a molded body. This molded body was degreased at 800 ° C. and then sintered at 1850 ° C. for 6 hours to prepare an AlN sintered body. The atmosphere during degreasing and sintering was a nitrogen atmosphere.
[0078]
In addition, 100 parts by weight of W powder having an average particle size of 2.0 μm, 1 part by weight of Y ₂ O ₃ powder, 0.6% by weight of Al ₂ O ₃ , ethyl cellulose as a binder, and butyl carbitol as a solvent Were added and mixed to prepare a W paste. A pot mill and three rolls were used for mixing. This W paste was screen printed to form a heater circuit pattern and a circular circuit on both surfaces of the AlN sintered body, respectively. The circular circuit can be a high frequency generating circuit or an electron beam (EB) irradiation circuit.
[0079]
The AlN sintered body on which the circuit was formed was degreased at 800 ° C. in a nitrogen atmosphere and then baked at 1800 ° C. for 6 hours in a nitrogen atmosphere to prepare a W conductor circuit. Moreover, a ceramic paste was prepared by adding a binder and an organic solvent to a powder composed of ₂₀ parts by weight of AlN, 30 parts by weight of Y ₂ O _{3, and the} remaining part of Al ₂ O ₃ . This ceramic paste was applied by screen printing on both surfaces of the AlN sintered body on which the W conductor circuit was formed, dried, and degreased at 800 ° C. in a nitrogen atmosphere. An AlN sintered body in which no conductor circuit is formed is laminated on both surfaces of the AlN sintered body, and hot pressing is performed in a nitrogen atmosphere at 1800 ° C. for 2 hours at a pressure of 2 MPa to produce a wafer holder. .
[0080]
From the surface opposite to the wafer holding surface of the wafer holder to the heater circuit pattern and the circular circuit pattern, spot facing was performed to expose part of both circuits. Furthermore, as shown in FIG. 5, screw processing was performed and the electrode was screwed. The electrode was made of W with a diameter of 3 mm and was plated with Ni.
[0081]
As shown in FIG. 1, the wafer holder to which the electrode was attached was supported by the electrode and attached in the container 10 of the semiconductor manufacturing apparatus. A wafer coated with a Low-K film was mounted, the wafer holder was heated to 400 ° C., and irradiated with an electron beam to process the wafer. As a result, a good Low-K film free from defects could be formed.
[0082]
Further, the same processing was performed on 10 wafers having a diameter of 12 inches, and the number of particles generated was examined. As a result, the average number of particles per wafer was 1.5. As shown in FIG. 2, as a result of a similar investigation using a conventional apparatus in which the wafer holder is supported by the SUS support 7, the number of particles is 4.5 on average, and the effect of the present invention is clear. It became.
[0083]
Example 2
A wafer holder similar to that in Example 1 was prepared, and electrodes were attached in the same manner as in Example 1. As shown in FIG. 3, a mullite-alumina composite pipe 6 was attached so as to surround the electrode. The pipe was made of zinc oxide-silica glass, joined to a wafer holder, and installed in a semiconductor manufacturing apparatus as shown in FIG.
[0084]
As described above, a Si wafer is mounted on the assembled semiconductor manufacturing apparatus, WF ₆ gas is introduced as a reaction gas, the wafer is heated to 500 ° C., and a high frequency of 13.56 MHz is applied to the circular circuit pattern. Then, plasma was generated to form a W film on the wafer. As a result, a good W film free from defects could be formed. In addition, no problem such as a spark occurred between the electrodes.
[0085]
Further, similarly to Example 1, ten wafers having a diameter of 12 inches were subjected to the same processing, and the number of generated particles was examined. As a result, the average number of particles per wafer was 1.8.
[0086]
Example 3
A wafer holder similar to that in Example 1 was prepared, and electrodes were attached. As shown in FIG. 4, the electrode was fixed to the base made from SUS, and the base and the container were airtightly sealed with the bellows made from Ni. The wafer holder was provided with three holes for penetrating the lift pins 5 at equal intervals, and installed so that the lift pins 5 fixed to the container 10 could pass therethrough. The heights of the tip surfaces of the three lift pins were adjusted to have a height variation within 0.5 mm.
[0087]
By moving the pedestal up and down, the lift pins protruded from the wafer holder or buried, thereby removing the wafer. This desorption was repeated 1000 times, but the wafer never dropped from the lift pins.
[0088]
On the other hand, when a conventional semiconductor manufacturing apparatus that moves the lift pins up and down was used, the wafer was detached 1000 times in the same manner, and the wafer dropped from the lift pins three times.
[0089]
In addition, the semiconductor manufacturing apparatus of the present invention does not require a mechanism for moving the lift pins up and down in synchronization with the conventional semiconductor manufacturing apparatus, so that the entire apparatus can be made compact.
[0090]
【The invention's effect】
As described above, according to the present invention, the wafer holder is supported and installed in the container of the semiconductor manufacturing apparatus by the electrode for supplying power to the electric circuit formed inside or on the surface of the holder. Therefore, a special support is not required, the volume of the container of the semiconductor manufacturing apparatus can be reduced, and the number of parts is reduced, so that generation of particles can also be suppressed.
[0091]
Further, the electrode is mounted on a vertically movable base, lift pins are installed and fixed on a container of a semiconductor manufacturing apparatus, and the base is driven up and down, whereby the wafer holder is driven up and down, and the lift pins are on the upper surface of the wafer holder. The wafer can be detached by protruding from (wafer holding surface) or being buried.
[0092]
For this reason, since the plurality of lift pins are fixedly installed on the container, it is easy to align the heights of the tip portions (wafer holding portions) of the plurality of lift pins, and there is no synchronization problem. At this time, the wafer can be prevented from dropping. In addition, since a mechanism for driving the lift pins in synchronism with each other is not required, the entire apparatus can be made compact.
[Brief description of the drawings]
FIG. 1 shows an example of a cross-sectional structure of a semiconductor manufacturing apparatus according to the present invention.
FIG. 2 shows an example of a cross-sectional structure of a conventional semiconductor manufacturing apparatus.
FIG. 3 shows an example of a cross-sectional structure of another semiconductor manufacturing apparatus of the present invention.
FIG. 4 shows an example of a cross-sectional structure of another semiconductor manufacturing apparatus of the present invention.
FIG. 5 shows an example of a cross-sectional structure of an electrode of a semiconductor manufacturing apparatus according to the present invention.
FIG. 6 shows an example of another cross-sectional structure of the electrode of the semiconductor manufacturing apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wafer holder 2 Resistance heating element circuit 3 Circular electrode circuit 4 Electrode 5 Lift pin 6 Cylindrical body 7 Support body 8 Screw part 9 Brazing material 10 Container 15 Base 16 Bellows 20 Ceramic component 21 Glass

Claims (5)

A semiconductor manufacturing apparatus, wherein a wafer holder for a semiconductor manufacturing apparatus is supported by an electrode for supplying power to an electric circuit formed inside or on the surface of the holder. The semiconductor manufacturing apparatus according to claim 1, wherein a cylindrical body is disposed so as to surround the electrode. The semiconductor manufacturing apparatus according to claim 1, wherein the electrode is fixed to a pedestal that is driven up and down. The semiconductor manufacturing apparatus according to claim 3, wherein the base and the container are hermetically sealed by a bellows. A plurality of through-holes through which lift pins are inserted are provided in a wafer holder for semiconductor manufacturing equipment, and the wafer holder can move up and down to allow the wafer to be attached to and detached from the wafer holder. The semiconductor manufacturing apparatus according to claim 3.

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