JP2000269189A - Method for plasma etching - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and accurately execute anisotropic etching of the so-called 'polymetal film'. SOLUTION: This method for plasma etching uses a substrate setting stage 10, which is constituted of a composite member 11 comprising a matrix 12 prepared by filling an aluminum based material in the texture of a ceramic member and a ceramic layer 13 provided on the surface of the matrix 12 and which has an electrostatic chucking function and is equipped with a temperature control means, and a substrate is set on the substrate setting stage 10 so that a layer to be treated on the substrate is etched. At this time, the layer to be treated comprises a silicon-based material layer and a metal layer which differ in etching characteristics from this silicon-based material layer, which are laminated in this sequence. The method comprises a process of etching the metal layer with the temperature of the substrate setting stage 10, controlled to be a first temperature (a) and a process of etching the silicon-based material layer, while the temperature of the stage 10 is controlled to be a second temperature different from the first one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma etching method, and more particularly, to an easy and accurate anisotropic etching of a so-called polymetal film in which a silicon-based material layer and a metal layer are laminated. To a plasma etching method.

[0002]

2. Description of the Related Art High integration and miniaturization of LSIs are unavoidable and mass production of LSIs having a design rule of 0.13 μm is scheduled in 2000 AD. Generally, a device that is an index of high integration is a DRAM,
The word line of the AM, that is, the line width of the gate electrode of the MIS transistor is used as an index of the design rule.

Conventionally, the gate electrode of a MIS transistor is typically formed using a polysilicon layer containing impurities. However, the wiring resistance increases due to the reduction in the cross-sectional area of the gate electrode, and In order to suppress the signal delay from becoming serious, it has been proposed to configure only the upper layer side of the gate electrode using a conductive material layer having a lower resistance than the polysilicon layer. Above all, a so-called polymetal film in which a metal layer made of a high melting point metal, particularly tungsten, is laminated on a polysilicon layer as such a conductive material layer is expected to be put to practical use in the future. Note that it is originally desirable that the entire gate electrode is composed of only a metal layer in order to thoroughly reduce the resistance of the gate electrode. However, considering the stability and reliability of the contact interface with the gate insulating film, the gate The lower part of the gate electrode in contact with the insulating film is preferably formed of a polysilicon layer as before, which is the reason why a polymetal film is used. When a polymetal film in which a tungsten layer of the same thickness is stacked on the polysilicon layer is used, the resistance can be reduced to about one fifth to one tenth as compared with a polysilicon layer of the same thickness. it can.

A gate electrode is formed by etching such a polymetal film by a plasma etching method. In etching the gate electrode, achieving an anisotropic shape,
In addition, it is extremely important to ensure selectivity with respect to a gate insulating film that is a base for etching. The anisotropic shape of the gate electrode is important for making the operating characteristics of the MIS transistor uniform. In a recent method of manufacturing a MIS transistor,
This is because the source / drain regions are formed in a self-aligned manner by ion implantation using the gate electrode as a mask, so that variations in the line width at the lower end of the gate electrode are directly linked to variations in the channel length. The selectivity to the gate insulating film is
This is important for preventing damage to a semiconductor substrate, particularly a silicon substrate, disposed below the gate insulating film. In particular, under the 0.13 μm design rule, the thickness of the gate insulating film is expected to be reduced to about 2.5 nm in order to lower the threshold voltage. An extremely high level of selectivity is indispensable in order to leave it on a semiconductor substrate without using it.

However, in the plasma etching method, generally, achieving an anisotropic shape and improving the underlayer selectivity are contradictory requirements. In addition, when considering a practical etching process, it is desirable that the etching reaction product has a sufficiently large vapor pressure within a temperature range that can be easily controlled in a normal semiconductor manufacturing field and can be quickly desorbed.
From such a viewpoint, for example, the following method is considered as a plasma etching method when a polymetal film including a tungsten layer is used as a layer to be processed. That is, (a)
While the temperature of the layer to be processed is maintained at around room temperature during the etching, a fluorine-based gas is used for etching the tungsten layer, and a chlorine-based gas / oxygen mixed gas or a bromine-based gas / oxygen mixed gas is used for etching the polysilicon layer. A method of switching the type of etching gas in the middle,
(B) A fluorine-based gas is used as an etching gas, and the layer to be processed is kept at 0 ° C. during the etching.
(C) A chlorine-based gas / oxygen mixed gas is used consistently as an etching gas, and a layer to be processed is kept at a temperature higher than room temperature when etching a tungsten layer. This is a method of keeping the layer to be processed near room temperature when etching the silicon layer.

In the method (a), at the time of etching a tungsten layer, tungsten fluoride having a high vapor pressure is generated even at around room temperature to promptly advance the etching.
This method is intended to achieve high selectivity to the gate insulating film by not using a fluorine-based etching species when etching the polysilicon layer. Here, a film generally assumed as the gate insulating film is a silicon oxide film, a silicon nitride film, or a stacked film combining these. The etching of the polysilicon layer proceeds by generating silicon chloride, silicon oxychloride, silicon bromide, and silicon oxybromide in accordance with the etching gas used, and differs due to the sidewall protection effect of the silicon oxide-based deposit. Ensure an isotropic shape.

The method (b) is a method called low-temperature etching. By lowering the temperature of the layer to be processed, the chemical reaction rate of the etching species is reduced and side migration is suppressed. It is intended to achieve an anisotropic shape mainly by advancing etching mainly using the kinetic energy of the etching species. This effectively suppresses the occurrence of undercut in the polysilicon layer, which has been difficult when a fluorine-based etching species is used near room temperature.

Further, in the method (c), the etching of the tungsten layer is performed at a temperature higher than room temperature, thereby increasing the vapor pressure of the tungsten oxychloride as an etching product to promote desorption, thereby performing the etching. This is a method that tries to proceed promptly. At the time of etching the polysilicon layer, the temperature of the layer to be processed is returned to around room temperature to prevent an excessive increase in the etching rate of the polysilicon layer, thereby avoiding the occurrence of undercut.

[0009]

However, each of the conventional methods has its own problems. First, in the method (a), the temperature of the layer to be processed is set near room temperature also when etching the tungsten layer in consideration of the vapor pressure of the etching reaction product at the time of etching the polysilicon layer. If the tolerance for dimensional conversion differences is increasingly reduced under the simplified design rules, it is extremely difficult to ensure sufficient dimensional accuracy if the tungsten layer is etched near room temperature with a fluorine-based gas. It is expected to be difficult. In order to solve this problem, it is necessary to change the temperature of the layer to be processed between the time of etching the tungsten layer and the time of etching the polysilicon layer. However, at present, etching processes having different temperatures in the same etching chamber are required. It is difficult to make progress continuously,
The etching chamber has to be divided.

[0010] The reason why it is difficult to advance the etching processes having different temperatures in the same etching chamber is related to the recent plasma etching apparatus configuration. Generally, when performing plasma etching, a substrate on which a layer to be processed is formed is mounted and fixed on a substrate mounting stage (which may be called a wafer stage) arranged in a chamber of an etching apparatus. The substrate is typically a semiconductor substrate such as a silicon substrate. Heating of the layer to be processed is usually performed by conducting heat from a heater built in the substrate mounting stage via the substrate. On the other hand, the layer to be processed is cooled by removing heat through the substrate by the refrigerant circulating in the substrate mounting stage. Therefore, the adhesion between the substrate mounting stage and the substrate greatly affects the in-plane temperature distribution of the substrate. When handling large-diameter substrates such as recent semiconductor substrates,
The uniformity of the in-plane temperature distribution is a factor that determines the success or failure of the etching process.

Therefore, a substrate mounting stage of a recent plasma etching apparatus has an electrostatic chuck function almost as a standard. The electrostatic chuck function is a function of applying a DC voltage to an internal electrode buried in a dielectric member and bringing the substrate into close contact by utilizing Coulomb force generated between the dielectric member and the substrate. Normally, the substrate mounting surface of the substrate mounting stage is formed of a dielectric member, and exhibits an electrostatic chuck function. However, if the temperature of the substrate mounting stage provided with the conventional electrostatic chuck is largely changed during the etching process, the temperature difference between the linear expansion coefficient of the substrate mounting stage and the linear expansion coefficient of the dielectric member is caused. As a result, cracks easily occur in the dielectric member, and the function as an electrostatic chuck is lost. Therefore, at present, etching processes having greatly different temperatures must be performed in independent etching chambers. This is likely to lead to an increase in the scale of manufacturing equipment, an increase in manufacturing cost, and a decrease in throughput.

In the method (b), when a polymetal film used for forming a gate electrode of a so-called dual gate type CMOS is assumed as the layer to be processed, the line width of the gate electrode is remarkably different between the NMOS and the PMOS. Problems arise. Dual gate CMOS means NMOS and PMO
In order to eliminate the asymmetry of the threshold voltage due to the work function difference of S, an n-type polysilicon layer is used for forming an NMOS gate electrode, and p-type is used for forming a PMOS gate electrode.
CMOS using a type polysilicon layer. Since the n-type polysilicon layer and the p-type polysilicon layer are formed by introducing an n-type impurity and a p-type impurity to a common polysilicon layer with their respective regions limited, NMO
The S and PMOS gate electrodes are formed simultaneously by a common etching process.

However, the etching rate of the n-type polysilicon layer by the commonly used etching species is higher than the etching rate of the p-type polysilicon layer.
If an attempt is made to achieve an anisotropic shape of the gate electrode on the MOS side, the line width of the gate electrode increases on the PMOS side, and conversely, the
When trying to achieve an anisotropic shape of the gate electrode on the S side, N
The line width of the gate electrode decreases on the MOS side. This tendency is emphasized as the temperature of the layer to be processed at the time of etching decreases. For this reason, even if the tungsten layer is etched by low-temperature etching, it is originally desirable that the polysilicon layer be etched near room temperature. However, it is difficult to continuously perform these etching processes having a large temperature difference in a single etching chamber as described above for the above-described reason.

In the method (c), the temperature of the layer to be processed at the time of etching is set high so that the tungsten oxychloride compound, which is an etching product of the tungsten layer, can have a sufficient vapor pressure. Tungsten oxychloride has a sufficiently high vapor pressure and requires heating close to 100 ° C. to promote desorption at a practically sufficient rate. However, since the subsequent etching of the polysilicon layer is performed at around room temperature, it is necessary to continuously perform these etching processes having a large temperature difference in a single etching chamber as described above for the same reason. Have difficulty.

It is an object of the present invention to provide a plasma etching method capable of easily and accurately performing anisotropic etching of a so-called polymetal film in which a silicon-based material layer and a metal layer are laminated. .

[0016]

According to the present invention, there is provided a plasma etching method comprising: a base material in which the structure of a ceramic member is filled with an aluminum-based material;
A composite member comprising a ceramic layer provided on the surface of the base material, having an electrostatic chuck function, and
A plasma etching method for mounting a substrate on a substrate mounting stage and etching a layer to be processed on the substrate using a substrate mounting stage provided with temperature control means, wherein the layer to be processed is a silicon-based material. And (b) a step of etching the metal layer while controlling the temperature of the substrate mounting stage to a first temperature. And (b) etching the silicon-based material layer while controlling the temperature of the substrate mounting stage to a second temperature different from the first temperature.

The control of the temperature of the substrate mounting stage is ultimately reflected in the temperature control of the layer to be processed by heat conduction through the substrate, but the temperature of the substrate mounting stage itself is the temperature of the layer to be processed. Is not always the same. This is because the temperature of the layer to be processed changes every moment due to the influence of plasma radiation heat and etching reaction heat. Therefore, for example, using a fluorescent fiber thermometer, by feedback control or feedforward control based on the measured value of the temperature,
It is preferable to control the temperature of the substrate mounting stage in real time.

It is particularly preferable that the metal layer is made of a high melting point metal material. Examples of the high melting point metal material include tungsten (W), molybdenum (Mo), tantalum (Ta), niobium (Nb), titanium (Ti), and nickel (Ni). Among them, tungsten is a proven and easy-to-use material.

The relationship between the first temperature in the step (a) and the second temperature in the step (b) depends on the combination of the type of the metal layer and the type of the etching gas. Any combination may be used as long as the temperatures are different. In particular, when the metal layer is made of tungsten, either (i) a method in which the first temperature is lower than the second temperature, and (ii) a method in which the first temperature is higher than the second temperature are possible. It is.

In the method (i), specifically, in the step (a), the metal layer is etched using a fluorine-based etching gas, and in the step (b), the silicon-based material layer is etched using a chlorine-based etching gas. It can be performed by etching.

In order to achieve a good anisotropic shape in the method (i), the first temperature in the step (a) is set to 0 °.
It is particularly preferable to select the temperature near C or lower and to select the second temperature in the step (b) near room temperature. In this case, the etching performed in step (a) is what is called low-temperature etching. The lower limit of the low-temperature etching temperature is not particularly limited, and a temperature at which a practical etching rate can be achieved may be appropriately selected within the range of the cooling ability by the temperature control means. The metal layer made of tungsten reacts with a fluorine-based etching species generated from a fluorine-based etching gas and is removed as tungsten fluoride.
At low temperatures, lateral migration of the fluorine-based etching species is suppressed, and an ion-assisted reaction mainly proceeds along the direction of ion incidence from the plasma, whereby anisotropic etching of the metal layer becomes possible. As the fluorine-based etching gas, F ₂ gas, CF ₄ gas, CHF ₃ gas, S
F ₆ gas, S ₂ F ₂ gas and C ₄ F ₈ gas can be exemplified.

In the step (b) of the method (i), a chlorine-based
Etching the polysilicon layer using the etching gas
However, when the etching reaction product is
To achieve atmospheric pressure, the chlorine-based etching gas must be
Oxygen-based etching species can be generated together with the etching species
Is particularly preferred. Use of such an etching gas
With this, the polysilicon layer is more vaporized than silicon chloride.
It is removed as low pressure silicon oxide
While etching proceeds at a speed, silicon and oxygen
Depositable silicon oxide as a reaction product with etching species
Provides sidewall protection and contributes to achieving anisotropic shape.
You. Moreover, the etching in the step (b) is performed at around room temperature.
If it is, the line width of the gate electrode of the dual gate type CMOS
Is significantly different between PMOS and NMOS
Difficult to manifest. Chlorine-based etching species and oxygen-based etching
As a chlorine-based etching gas capable of simultaneously generating seeds,
Cl _TwoGas and O_TwoGas mixture with gas, BCl_ThreeGas and O_TwoMoth
Gas, or salt in the molecule like chlorine oxide
Illustrates a compound gas containing both elemental and oxygen atoms
be able to.

In the method (i), the layer to be processed may further include a barrier layer between the silicon-based material layer and the metal layer. The barrier layer suppresses an alloying reaction between the silicon-based material layer and the metal layer, or diffuses impurities contained in the silicon-based material layer into the metal layer and causes the resistance value of the silicon-based material layer to increase. Is a layer provided for the purpose of preventing the fluctuation of the thickness. When the barrier layer is provided on the layer to be processed, the metal layer is not limited to tungsten. A typical constituent material of the barrier layer is a metal nitride, and examples thereof include tungsten nitride, titanium nitride, and tantalum nitride. The constituent material of the barrier layer can be selected from conductive materials that can exhibit good adhesion to both the silicon-based material layer and the metal layer, depending on the type of metal layer used. When the layer to be processed includes a barrier layer, it is necessary to etch the barrier layer in the step (a) or the step (b). In which step, the barrier layer is etched depends on the constituent material of the barrier layer. Dependent. If the constituent material of the barrier layer is a material that can be etched with a fluorine-based etching species, for example, tungsten nitride, the step (a) can be performed subsequent to the etching of the metal layer, and a chlorine-based etching such as titanium nitride is used. Any material that can be etched by the seed can be used in step (b) prior to etching the polysilicon layer.

On the other hand, in the method (ii) in which the first temperature is higher than the second temperature, the metal layer is etched using a chlorine-based etching gas in the step (a). In the above, the etching can be performed by etching the silicon-based material layer using a chlorine-based etching gas.

In the step (a) of the method (ii), when the tungsten layer is etched using a chlorine-based etching gas, the etching reaction product has a sufficient vapor pressure near the room temperature for desorption. It is particularly preferred that the system-based etching gas can generate oxygen-based etching species together with chlorine-based etching species. By using such an etching gas, the tungsten layer is removed as tungsten oxychloride having a lower vapor pressure than tungsten chloride, and the etching proceeds at a practical rate. The first temperature is preferably selected to be approximately 80 to 130 ° C., but when the etching mask includes an organic resist layer, the first temperature is set to 100 ° C. in consideration of the heat resistance of the organic resist layer.
The degree is the upper limit. When the first temperature is set to a temperature exceeding 100 ° C., the etching mask needs to be formed using an inorganic compound layer. The configuration of the etching mask will be described later.

The composition of the chlorine-based etching gas, the etching mechanism, and the setting of the second temperature in the step (b) of the method (ii) are as described in relation to the method (i). According to the method (ii), it is not necessary to switch the type of the etching gas during the etching process.
The operation of the plasma etching apparatus is simplified. If the etching of the tungsten layer in the step (a) is performed using a fluorine-based etching gas, the exhaust gas in the chamber must be thoroughly exhausted before proceeding to the step (b) to select the gate insulating film depending on the remaining fluorine-based etching species. However, such a problem does not occur because no fluorine-based etching gas is used in the method (ii).

In the method (ii), the layer to be processed may further include a barrier layer between the silicon-based material layer and the metal layer. The constituent material of the barrier layer is as described in connection with the method (i). In the method (ii), whether the barrier layer is etched in the step (a) or the step (b) depends on a constituent material of the barrier layer. In the method (ii), the chlorine-based etching gas is used in both the step (a) and the step (b), so that the etching reaction product (chloride and / or acid chloride) of the barrier layer is desorbed unless the temperature is high. If it cannot be obtained, it can be etched in step (a), and if it can be desorbed even at room temperature, it can be etched in step (b). For example, the barrier layer made of tungsten nitride is preferably etched in step (a), and the barrier layer made of titanium nitride is preferably etched in step (b).

In the method (ii), prior to the step (a), an etching mask containing at least an inorganic compound layer may be formed on the layer to be processed. This is the process (a)
If the first temperature in (1) exceeds 100 ° C., it becomes difficult to use the organic resist layer. However, the etching mask including the inorganic compound layer may be used in the method (i). This is because the inorganic compound layer can be used as an etching stop layer in a self-aligned contact process, for example, by being left after the end of the etching. The etching mask including the inorganic compound layer may be a single mask composed of only the inorganic compound layer or a composite mask in which an organic resist layer used for patterning the inorganic compound layer is left on the inorganic compound layer. There may be. As the inorganic compound layer, S
iO _2, SiN, SiON, can be exemplified SOG (spin on glass). However, since these silicon oxide-based materials and silicon nitride-based materials are easily attacked by fluorine-based etching species, when they are used as etching masks for etching using fluorine-based etching species, composite materials combined with an organic resist layer are used. It is particularly preferable to use it as a mask.

The member formed by the plasma etching method of the present invention may be any member.
The gate electrode of the IS type transistor can be formed easily and with high precision.

By the way, in the plasma etching method of the present invention, a difference of typically several tens degrees Celsius occurs in the temperature of the substrate mounting stage between the step (a) and the step (b), 100 ° per minute
It is required to change the temperature of the substrate mounting stage at a temperature rise / fall rate of about C. If the temperature of the substrate mounting stage provided with the conventional electrostatic chuck is to be changed so greatly and rapidly during the etching process, the linear expansion coefficient of the substrate mounting stage and the linear expansion coefficient of the dielectric member are increased. Cracks easily occur in the dielectric member due to the difference between
The function as an electrostatic chuck is lost. But,
In the plasma etching method of the present invention, this problem is solved by using a substrate mounting stage whose structure and constituent materials have been studied in detail. Can be performed continuously. Hereinafter, the substrate mounting stage will be described.

In the plasma etching method of the present invention, a substrate mounting member composed of a composite member comprising a base material in which the structure of a ceramic member is filled with an aluminum-based material and a ceramic layer provided on the surface of the base material is provided. Since the placing stage is used, even if the temperature of the substrate placing stage is rapidly raised and lowered, the ceramic layer is not damaged and the substrate, and further, the layer to be processed formed on the substrate is heated to a high temperature, or It becomes possible to cool to a low temperature. as a result,
Vaporization of the reaction product can be promoted, and fine processing of the processed layer can be reliably performed. Moreover, since the substrate mounting stage has an electrostatic chuck function, the substrate can be securely brought into close contact with the substrate mounting stage.
Furthermore, the layer to be processed formed on the substrate can be effectively heated to a high temperature or cooled to a low temperature under excellent temperature control.

The base material itself constituting the base mounting stage may be used as an electrode itself, or an electrode may be formed inside the ceramic layer. By applying a DC voltage to the electrode, the base mounting stage can be statically mounted. An electric chuck function can be provided.

The temperature control means provided on the substrate mounting stage can be constituted by a heater. The heater may be provided outside the composite member or inside the base material. In the latter case, the linear expansion coefficient of the base material is α ₁ [unit: 1
0 ⁻⁶ / K], the linear expansion coefficient α _H [unit: 10 ⁻⁶ / K] of the material constituting the heater is (α ₁ -4) ≦ α _H ≦ (α ₁
+4) is preferably satisfied. Here, the material constituting the heater means a material constituting a portion (for example, a sheath tube) of the heater in contact with the base material. The same applies to the following. In general, the linear expansion coefficient α can be expressed as α = (dL / dθ) / L ₀ where L is the length of the object, L _{0 is} the length of the object at 0 ° C., and θ is the temperature. The unit is K ^-1 (1 / K), but in the present specification, 10 ^-6 /
The coefficient of linear expansion is expressed in units of K. Hereinafter, when the linear expansion coefficient is described, a unit may be omitted in some cases.

Alternatively, the temperature control means provided on the base mounting stage is constituted by a pipe for flowing a heat medium for temperature control (hereinafter simply referred to as a heat medium) provided inside the base material. You can also. In this case, the linear expansion coefficient of the base material is α ₁
When [unit: 10 ⁻⁶ / K], the coefficient of linear expansion of the pipe α _P
[Unit: 10 ⁻⁶ / K] is (α ₁ -4) ≦ α _P ≦ (α ₁ +
It is preferable to satisfy the relationship of 4). It is particularly preferable that this pipe is provided with the above-described heater.

When the linear expansion coefficient α _{1 of the} base material and the linear expansion coefficients α _H and α _{P of} the material and piping constituting the heater satisfy these relationships, it is possible to effectively prevent the ceramic layer from being damaged. Can be prevented.

The coefficient of linear expansion of the base material is α ₁ [unit: 10
⁻⁶ / K], the coefficient of linear expansion α of the ceramic layer
₂ [unit: 10 ⁻⁶ / K] is (α ₁ -4) ≦ α ₂ ≦ (α ₁ +
It is preferable to satisfy the relationship of 4). by this,
It is rapidly raised and lowered the temperature of the substrate mounting stage between different etch process temperature, to ensure the occurrence of damage of the ceramic layer due to the difference in linear expansion coefficient alpha ₂ of the linear expansion coefficient alpha ₁ and the ceramic layer of the base material This can be prevented.

Such a base material is prepared by, for example, (A) filling a structure of a ceramic member with an aluminum-based material and thereby forming a base material with the structure of the ceramic member filled with an aluminum-based material. And (B) providing a ceramic layer on the surface of the base material.

In this case, the composition of the ceramic member forming the base material is cordierite ceramics, and the composition of the aluminum-based material forming the base material is aluminum (A
1) and silicon (Si), and the material constituting the ceramic layer can be aluminum oxide (Al ₂ O ₃ ) or aluminum nitride (AlN). Note that, for example, TiO ₂ may be added to the material constituting the ceramic layer in order to adjust the coefficient of linear expansion and electrical characteristics of the ceramic layer. It is desirable to determine the volume ratio between the cordierite ceramics and the aluminum-based material so as to satisfy the relationship of (α ₁ -4) ≦ α ₂ ≦ (α ₁ +4). Alternatively, the volume ratio of cordierite ceramics / aluminum-based material is desirably 25/75 to 75/25, preferably 25/75 to 50/50. With such a volume ratio, not only the control of the coefficient of linear expansion of the base material, but also the base material has a value closer to the metal than the electrical conductivity or thermal conductivity of pure ceramics. As a result, it is possible to apply not only a voltage but also a bias to such a base material, and it is possible to promote the vaporization of the reaction product. Further, based on an aluminum-based material, the aluminum-based material contains 12 to 35% by volume, preferably 16 to 35% by volume, and more preferably 20 to 35% by volume of silicon. It is desirable to satisfy the relationship of α ₁ -4) ≦ α ₂ ≦ (α ₁ +4). Actually, the structure of a ceramic member made of cordierite ceramics is filled with aluminum (Al) and silicon (Si), and silicon (Si) is not contained in aluminum (Al). However, in order to express the volume ratio between aluminum (Al) and silicon (Si) in an aluminum-based material, the expression that aluminum-based material contains silicon is used. The same applies to the following.

When the composition of the ceramic member forming the base material is cordierite ceramics and the composition of the aluminum-based material forming the base material is aluminum (Al) and silicon (Si), the above-mentioned step (A) is performed as follows. A ceramic member composed of porous cordierite ceramics is placed in a container, and an aluminum-based material composed of molten aluminum and silicon is poured into the container, and the ceramic member is formed by high-pressure casting. Preferably, the method comprises a step of filling an aluminum-based material. In this case, the ceramic member is, for example, a die press molding method,
Forming cordierite ceramics by isostatic pressing (also called CIP method or rubber press forming method), casting method (also called slip casting method), or slurry casting method, and then firing (sintering). Can be obtained by:

The ceramic member can be produced by forming cordierite ceramic powder and then firing the same. However, a mixture of the cordierite ceramic powder and the cordierite ceramic fibers is fired (sintered). This is preferable in order to obtain a porous ceramic member and to prevent the ceramic member from being damaged when the base material is manufactured. In the latter case, the ratio of the cordierite ceramic fibers in the fired body (sintered body) is desirably 1 to 20% by volume, preferably 1 to 10% by volume, and more preferably 1 to 5% by volume. The average particle diameter of the cordierite ceramic powder is 1 to 100 μm, preferably 5 to 50 μm, more preferably 5 to 10 μm, and the average diameter of the cordierite ceramic fibers is 2 to 10 μm, preferably 3 to 5 μm. The average length is desirably 0.1 to 10 mm, preferably 1 to 2 mm. Further, a mixture of cordierite ceramics powder and cordierite ceramics fiber is mixed with 8
00 to 1200 ° C, preferably 800 to 1100
It is desirable to fire (sinter) at ゜ C. The porosity of the ceramic member is 25 to 75%, preferably 5 to 75%.
It is desirably 0 to 75%.

The temperature of the ceramic member when the molten aluminum material is poured into the container is set to 500 to 1000 ° C., preferably 700 to 800 ° C.
When the temperature of the aluminum-based material at the time of pouring the molten aluminum-based material into the container is set to 700 to 1000 ° C., preferably 750 to 900 ° C., The absolute pressure to be applied is desirably 200 to 1500 kgf / cm ² , preferably 800 to 1000 kgf / cm ² .

Alternatively, the composition of the ceramic member forming the base material is aluminum nitride (AlN), and the composition of the aluminum-based material forming the base material is aluminum (A
1) Or aluminum (Al) and silicon (Si), and the material constituting the ceramic layer can be aluminum oxide (Al ₂ O ₃ ) or aluminum nitride (AlN). In addition, in order to adjust the coefficient of linear expansion and electrical characteristics of the ceramic layer,
For example, TiO ₂ or Y _x O _y may be added. In this case, it is preferable to determine the volume ratio between aluminum nitride and the aluminum-based material so as to satisfy the relationship of (α ₁ -4) ≦ α ₂ ≦ (α ₁ +4). Alternatively, the volume ratio of aluminum nitride / aluminum-based material is set to 40/60.
To 80/20, preferably 60/40 to 70/30
It is desirable that By making such a volume ratio, not only the control of the coefficient of linear expansion of the base material, the base material comes to have a value closer to the metal than the electrical conductivity or thermal conductivity of pure ceramics, Such a base material can be applied with a bias as well as a voltage,
It is possible to promote the vaporization of the reaction product. When the composition of the aluminum-based material constituting the base material is aluminum and silicon, silicon is contained in the aluminum-based material in an amount of 12 to 35% by volume, preferably 16 to 35% by volume,
More preferably, it is contained in an amount of 20 to 35% by volume in order to satisfy (α ₁ -4) ≦ α ₂ ≦ (α ₁ +4).

When the composition of the ceramic member forming the base material is aluminum nitride (AlN) and the composition of the aluminum-based material forming the base material is aluminum (Al), the above-mentioned step (A) is performed under the non-pressurized condition. Based on metal infiltration method,
It is preferable that the method comprises a step of infiltrating an aluminum-based material having a composition of molten aluminum into a ceramic member formed from aluminum nitride particles in a non-pressurized state. The ceramic member is formed by, for example, a die press molding method, a hydrostatic molding method, a casting method, or a slurry casting method, and then fired at a temperature of 500 to 1000 ° C., preferably 800 to 1000 ° C. (Sintering). In this case, the average particle size of the aluminum nitride particles is 10 to 100.
μm, preferably 10 to 50 μm, more preferably 1 μm
Desirably, the thickness is 0 to 20 μm.

Alternatively, the composition of the ceramic member forming the base material is silicon carbide (SiC), and the composition of the aluminum-based material forming the base material is aluminum (Al) or aluminum (Al) and silicon (Si); Aluminum oxide (Al)
₂ O ₃ ) or aluminum nitride (AlN). Note that, for example, TiO ₂ may be added to the material constituting the ceramic layer in order to adjust the coefficient of linear expansion and electrical characteristics of the ceramic layer. In this case, assuming that the linear expansion coefficient of the base material is α ₁ [unit: 10 ⁻⁶ / K], the linear expansion coefficient α ₂ [unit: 10 ⁻⁶ / K] of the ceramic layer is (α ₁ −
4) It is desirable to determine the volume ratio between the silicon carbide particles and the aluminum-based material so as to satisfy ≦ α ₂ ≦ (α ₁ +4). Alternatively, the volume ratio of silicon carbide particles / aluminum-based material is desirably 40/60 to 80/20, preferably 60/40 to 70/30. By adopting such a volume ratio, not only the control of the coefficient of linear expansion of the base material, but also the base material has a value closer to the metal than the electrical conductivity or thermal conductivity of pure ceramics, A voltage can be applied to such a base material as well as a bias can be applied, and the vaporization of the reaction product can be promoted. When the composition of the aluminum-based material constituting the base material is aluminum and silicon, the aluminum-based material contains 12 to 35% by volume of silicon, preferably 16 to 35% by volume, and more preferably 20 to 3% by volume.
5% by volume is expressed as (α ₁ -4) ≦ α ₂ ≦ (α
It is desirable to satisfy ₁ + 4).

In this case, in the step (A), based on a non-pressurized metal infiltration method, molten aluminum or an aluminum-based material containing aluminum and silicon in a ceramic member formed from silicon carbide particles is subjected to non-pressurizing. Preferably, the method comprises a step of infiltrating in a state. Alternatively, in the step (A), a ceramic member composed of silicon carbide is placed in a container, and molten aluminum or an aluminum-based material composed of aluminum and silicon is poured into the container. And filling the ceramic member with an aluminum-based material by heating. In this case, when the molten aluminum-based material is poured into the container, the temperature of the ceramic member is set to 500 to 1
2,000 ° C, and the absolute pressure applied when filling the ceramic material with the aluminum-based material by the high pressure casting method is 20
It is desirable to set it to 0 to 1500 kgf / cm ² .
The ceramic member is formed, for example, by a die press molding method, a hydrostatic molding method, a casting method, or a slurry casting method, and then fired at a temperature of 500 to 1000 ° C, preferably 800 to 1000 ° C. Can be obtained by: The average particle size of the silicon carbide particles is 1
The thickness is desirably from 10 to 80 μm, preferably 10 to 80 μm, and more preferably 15 to 60 μm.

Alternatively, the ceramic constituting the base material
The composition of the member is aluminum oxide (Al_TwoO_Three) And mother
The composition of the aluminum-based material constituting the material is aluminum
(Al) or aluminum (Al) and silicon (Si)
Yes, the material for the ceramic layer is aluminum oxide
(Al_TwoO_Three). In addition, ceramics
The material constituting the layer includes the coefficient of linear expansion of the ceramic layer and the
In order to adjust the air quality, for example, TiO_TwoAdd
Is also good. In this case, (α₁-4) ≦ α_Two≤ (α₁+4)
Aluminum oxide and aluminum based material to satisfy
It is preferable to determine the volume ratio with the material. Alternatively,
The volume ratio of aluminum oxide / aluminum-based material is 5
0/50 to 90/10, preferably 70/30 to 8
5/15 is desirable. In such a volume ratio
In addition to controlling the coefficient of linear expansion of the base material,
The material is based on the electrical and thermal conductivity of pure ceramics.
Even have values approaching that of metals, such a mother
It is possible to apply bias as well as voltage to the material
Thus, the vaporization of the reaction product can be promoted.
Note that the composition of the aluminum-based material constituting the base material is aluminum
In the case of aluminum and silicon, aluminum-based materials include
12 to 35% by volume of silicon, preferably 16 to 35% by volume
% By volume, more preferably 20 to 35% by volume.
Is (α ₁-4) ≦ α_Two≤ (α₁+4)
Desirable above. The average particle size of aluminum oxide is 1 to 1
00 μm, preferably 10 to 80 μm, more preferably
Is preferably 10 to 60 μm.

The composition of the ceramic member forming the base material is aluminum oxide, and the composition of the aluminum-based material forming the base material is aluminum (Al) and silicon (Si).
In the above step (A), in the step (A), a ceramic member composed of porous aluminum oxide is disposed in a container, and an aluminum-based material composed of molten aluminum and silicon is poured into the container, Preferably, the method comprises a step of filling the ceramic member with an aluminum-based material by a high-pressure casting method. In this case, the temperature of the ceramic member when the molten aluminum-based material is poured into the container is set to 500 to 1000 ° C. It is desirable that the absolute pressure applied when the ceramic member is filled with the aluminum material by the casting method be 200 to 1500 kgf / cm ² . Alternatively, the above-mentioned step (A) comprises:
Preferably, the method comprises a step of infiltrating a ceramic material molded from aluminum oxide particles with an aluminum-based material containing aluminum and silicon in a non-pressurized state based on a non-pressurized metal infiltration method. The ceramic member can be obtained, for example, by molding by a die press molding method, an isostatic molding method, a casting molding method, or a slurry casting molding method, followed by firing (sintering).

The ceramic layer is preferably formed on the surface of the base material by a thermal spraying method. As a result, the stress between the base material and the ceramic layer can be relaxed, and the heat conduction from the base material to the ceramic layer can be accelerated. Can be performed quickly and reliably. Alternatively, the ceramic layer is preferably attached to the surface of the base material by a brazing method. Here, the linear expansion coefficient of the brazing material [unit: 10 ⁻⁶ / K] is also ^{defined assuming that} the linear expansion coefficient of the base material is α ₁ [unit: 10 ⁻⁶ / K].
It is desirable to be within the range of (α ₁ -4) or more and (α ₁ +4) or less.

In the plasma etching method of the present invention,
As a substrate on which a layer to be processed is formed, a gate insulating film provided on a substrate, an insulating layer provided on the substrate, an insulating layer provided on the substrate, and a connection hole provided in the insulating layer (Contact holes, via holes, etc.), an underlayer made of a metal or a metal compound provided on an insulating layer provided on the substrate (for example, a lower electrode constituting a capacitor structure), provided on the substrate. And a combination of a base layer made of a metal or a metal compound provided on the insulating layer (for example, a lower electrode constituting a capacitor structure). Examples of the substrate constituting the base include a compound semiconductor such as a silicon semiconductor substrate and a GaAs substrate or a semi-insulating substrate, and a semiconductor substrate having an SOI structure. The insulating layers constituting the base are made of SiO ₂ , BPSG, PSG, BSG, As.
SG, PbSG, SbSG, NSG, SOG, LTO
(Low Temperature Oxide, low temperature CVD-SiO ₂ ), S
Known materials such as iN, SiON, and fluorocarbon, or a laminate of these materials can be exemplified.

The method of forming the layer to be processed depends on the material constituting the layer to be processed, but may be a CVD method, a sputtering method, an MO method.
A CVD method, a pulse laser ablation method, and a sol-gel method can be given.

The plasma can be generated by, for example, an ECR plasma excitation method, an ICP (inductively coupled plasma) excitation method, or a helicon wave plasma excitation method.

In the plasma etching method using an etching gas, a deposit of a reaction product (etching product) is excessively deposited on a side wall or a top plate of a chamber of an etching apparatus. Therefore, there is a possibility that the processing of the layer to be processed is impaired. That is, the reaction product accumulates on the chamber side wall and the top plate before reaching the exhaust unit provided in the etching apparatus. Therefore, when etching is repeated, the reaction products deposited on the chamber side wall and the top plate are peeled off,
As a result of becoming a particle source, there is a possibility that a problem that the particle level is deteriorated may occur.

In such a case, it is preferable to perform the plasma etching of the layer to be processed while maintaining the temperature of the chamber side wall and the top plate of the etching apparatus at a temperature equal to or higher than the temperature of the layer to be processed. It is preferable to keep the temperature in the range of 400 ° C.

The chamber side wall and the top plate are made of a composite member composed of a base material in which the structure of the ceramic member is filled with an aluminum-based material and a ceramic layer provided on the surface of the base material. Is preferred.
Such a composite member can be configured substantially the same as the composite member constituting the base mounting stage, and can be manufactured by substantially the same manufacturing method as the composite member. The composite member is provided with a temperature control means, and this temperature control means is preferably constituted by a heater or a pipe. The heater may be provided outside the composite member or inside the base material. In the latter case, the linear expansion coefficient of the base material is α ′ ₁ [unit: 10 ⁻⁶ / K] , The linear expansion coefficient α ′ _{H of} the material constituting the heater [unit: 1
0 ⁻⁶ / K] preferably satisfies the relationship of (α ′ ₁ -4) ≦ α ′ _H ≦ (α ′ ₁ +4). The linear expansion coefficient α ′ _P [unit: 10 ⁻⁶ / K] of the pipe is (α ′ ₁ -4) ≦ α ′ _P ≦
It is preferable to satisfy (α ′ ₁ +4). Furthermore, the coefficient of linear expansion α ′ ₂ [unit: 10 ⁻⁶ / K] of the ceramic layer desirably satisfies (α ′ ₁ -4) ≦ α ′ ₂ ≦ (α ′ ₁ +4).

From such a composite member, the chamber side wall,
By manufacturing the top plate, the base material has an intermediate property between the ceramic member and the aluminum-based material. For example, the coefficient of linear expansion can be adjusted to an intermediate value between these. Therefore, it is possible to prevent the ceramic layer from being damaged due to the thermal expansion between the base material and the ceramic layer, and it is possible to reliably use the chamber side wall and the top plate made of the composite member at a high or low temperature.
As a result, even if the chamber side wall and the top plate are maintained at a sufficiently high temperature to prevent the reaction products from being deposited on the chamber side wall and the top plate, the ceramic layer is not damaged and the chamber side wall and the top plate are not damaged. Heating to a desired temperature can be ensured. Furthermore, since the ceramic layer is provided, it is possible to prevent the occurrence of metal contamination and the occurrence of corrosion of the composite member due to, for example, an etching gas composed of a halogen-based gas.

In the conventional etching apparatus, the side wall of the chamber is usually made of stainless steel or aluminum. Then, for example, during the etching process, in order to prevent the occurrence of metal contamination due to direct exposure to plasma and the occurrence of corrosion of the chamber side wall due to halogen-based gas, the chamber side wall made of aluminum is formed. An Al ₂ O ₃ layer (alumite layer) is formed on the surface. When the chamber side wall is made of stainless steel, Al ₂ O ₃
A reflector made of aluminum is arranged near the side wall of the chamber inside the etching apparatus. When high-temperature heating or low-temperature cooling of the chamber side wall is performed in such a state, when the chamber side wall is made of aluminum, due to the difference in linear expansion coefficient between aluminum and Al ₂ O ₃ , The formed Al ₂ O ₃ layer is apt to crack. Further, when a reflector made of Al ₂ O ₃ is arranged near the side wall of the chamber inside the etching apparatus, it is difficult to sufficiently heat the reflector from outside the etching apparatus. That is, it is difficult to heat the reflector to a temperature at which all the reaction products incident on the reflector are separated from the reflector, and the reflector can be heated only up to about 100 ° C.

Alternatively, in the case where the etching apparatus is provided with a parallel plate upper counter electrode, the upper counter electrode is formed of a base material in which the structure of a ceramic member is filled with an aluminum-based material, and a surface of the base material. It is preferable to manufacture from a composite member comprising the ceramic layer provided on the substrate. Such a composite member can be configured substantially the same as the composite member forming the substrate mounting stage,
It can be manufactured by substantially the same manufacturing method as such a composite member. Note that the coefficient of linear expansion of the base material is α ″ ₁ [unit: 10
⁻⁶ / K], the coefficient of linear expansion of the ceramic layer α ″ ₂
[Unit: 10 ⁻⁶ / K] is (α ″ ₁ −4) ≦ α ″ ₂ ≦
It is preferable that (α ″ ₁ +4) be satisfied.
The upper counter electrode is preferably provided with a temperature control means, and more preferably, the temperature control means is constituted by a heater. Thus, for example, the upper counter electrode can be heated to a temperature at which the precursor incident on the surface of the upper counter electrode is separated from the upper counter electrode. The heater may be disposed outside the composite member or inside the base material. In the latter case, the linear expansion coefficient of the base material is α ″ ₁ [unit: 10 ⁻⁶ / K] Where, the linear expansion coefficient α ″ _H [unit: 10 ⁻⁶ / K] of the material constituting the heater is (α ″ ₁ −4) ≦ α ″ _H ≦ (α ″ ₁ +
It is preferable to satisfy 4). Base material linear expansion coefficient α ” ₁
When the linear expansion coefficient α ″ _{H of} the material constituting the heater satisfies this relationship, it is possible to effectively prevent the ceramic layer from being damaged. If the upper counter electrode is formed on the surface of the base material, the upper counter electrode can be easily formed even if the size of the upper counter electrode is large. May be attached.
The temperature of the upper counter electrode during plasma etching is
It is desirable that the temperature be controlled between 100 ° C. and 400 ° C.

[0058]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings based on embodiments of the present invention (hereinafter, abbreviated as embodiments).

(Embodiment 1) In Embodiment 1, a plasma etching method of the present invention is applied to a dual gate type CMO.
It was applied to the formation of the S gate electrode. FIG. 1 is a schematic cross-sectional view of a substrate mounting stage used in the plasma etching method of the present invention. FIG. 2 is a conceptual diagram of a plasma etching apparatus provided with such a substrate mounting stage. FIG. 2 shows a process chart for forming a gate electrode of a dual gate type CMOS.

FIG. 1A is a schematic cross-sectional view of the substrate mounting stage 10 composed of a composite member. The substrate mounting stage 10 is composed of a composite member 11. The composite member 11 includes a base material 12 (corresponding to a temperature control jacket) in which the structure of the ceramic member is filled with an aluminum-based material, and a ceramic layer 13 provided on the surface of the base material 12. The shape of the base material 12 is a disk. The substrate mounting stage 10 has an electrostatic chuck function and includes a temperature control unit. Specifically, the ceramic layer 13 as a dielectric layer has an electrostatic chuck function. Further, a temperature control means is provided (embedded) inside the base material 12, and the temperature control means comprises a heater 14 and a pipe 15 for flowing a heat medium.

In the first embodiment, the composition of the ceramic member constituting the base material 12 is cordierite ceramic. Here, cordierite ceramics means about 13% by weight of MgO, about 52% by weight of SiO ₂ ,
It is a ceramic whose composition ratio is adjusted so that Al ₂ O ₃ is about 35% by weight. The coefficient of linear expansion of cordierite ceramics is 0.1 × 10 ⁻⁶ / K.

The composition of the aluminum-based material constituting the base material 12 is aluminum (Al) and silicon (Si).
It is. In the first embodiment, the aluminum-based material contains 20% by volume of silicon based on the aluminum-based material. The ceramic member was a fired body of a mixture of cordierite ceramic powder and cordierite ceramic fiber, and the ratio of the cordierite ceramic fiber in the fired body was 5% by volume. Here, the average particle diameter of the cordierite ceramic powder is 10 μm, the average diameter of the cordierite ceramic fibers is 3 μm, and the average length is 1 mm.
The porosity of the ceramic member is about 50%, and the pore diameter is about 1 to 2 μm. Therefore, the volume ratio of cordierite ceramics / aluminum-based material is about 1/1. The linear expansion coefficient of the base material 12 having such a configuration is 100 to
About 10.6 × 10 ⁻⁶ / K at an average value at 300 ° C.
It is. That is, α ₁ = 10.6. The volume ratio of cordierite ceramics / aluminum material is about 1/1
Therefore, the base material 12 has a value closer to the metal than the electrical conductivity or the thermal conductivity of pure ceramics. Therefore, not only a voltage but also a bias can be applied to the substrate mounting stage 10 manufactured from such a base material 12.

The material constituting the ceramic layer 13 is T
iO_TwoAbout 2.5% by weight of Al_TwoO_ThreeAnd Thick
The ceramic layer 13 having a thickness of about 0.2 mm is
It is formed on the surface of the material 12. Sera of such composition
The linear expansion coefficient of the mix layer 13 is 100 to 300 ° C.
About 9 × 10^-6/ K. Therefore, α _Two
Is about 9, and the coefficient of linear expansion α of the ceramic layer 13 is_TwoIs
(Α₁-4) ≦ α_Two≤ (α₁+4). still,
Al_TwoO_ThreeIts own coefficient of linear expansion is about 8 × 10^-6/ K
You. Also, Al_TwoO_ThreeTiO2_TwoAbout 2.5% by weight
The volume resistivity of the ceramic layer 13
10¹¹It can be adjusted to the order of Ω / □. this
Thereby, the ceramic layer 13 acts as a dielectric,
The function as an electrostatic chuck can be exhibited. This
The reason for adjusting the volume resistivity as in
Layer 13 is 10¹¹If it exceeds the Ω / □ order,
When the ceramic layer 13 is used as a
It becomes too weak, and the substrate is sufficiently adsorbed on the ceramic layer 13.
This is because there is a possibility that it may be difficult to perform the operation. On the other hand,
Lamix layer 13 is 10¹¹Below the Ω / □ order,
When the substrate mounting stage 10 is used at a high temperature, the ceramic
The resistance of the layer 13 is further reduced, and the substrate and the ceramic layer
There is a possibility that a current is generated at the interface with the semiconductor device 13. The usage conditions
Generally, the volume resistivity of the ceramic layer depends on the
10¹¹-10¹⁶Ω / □ is desirable.

As shown in the schematic sectional view of FIG. 1B, a ceramic layer may be provided on the surface of the base material 12 by a brazing method instead of a thermal spraying method. In this case, a ceramic layer 16 made of an Al ₂ O ₃ ceramic plate manufactured by a sintering method was used, for example, using an Al—Mg—Ge brazing material 17 at a temperature of about 600 ° C. What is necessary is just to attach to the surface of the base material 12 by the brazing method. In addition, brazing material 1
Other examples of 7 include alloys composed of titanium, tin, antimony, and magnesium. Brazing material 17
The linear expansion coefficient [unit: 10 ⁻⁶ / K] is also (α ₁ -4) when the linear expansion coefficient of the base material 12 is α ₁ [unit: 10 ⁻⁶ / K].
As described above, it is desirable that the value be within the range of (α ₁ +4) or less. If necessary, an annular cover made of a ceramic material may be attached to the side surface of the base mounting stage 10.

As the heater 14, a large-capacity sheathed heater corresponding to the area (bottom area) of the base material 12 was used.
The heater 14 is a known heater including a heater body (not shown) and a sheath tube (not shown) provided outside the heater body and protecting the heater body. Heater 1
Reference numeral 4 is connected to a power supply via a wiring (not shown).
The thermal expansion of the heater 14 affects the substrate mounting stage 10. Therefore, it is preferable to use a material having values close to the linear expansion coefficients α ₁ and α ₂ of the base material 12 and the ceramic layer 13. Specifically, titanium or stainless steel or the like, it is preferable that the linear expansion coefficient which sheath tube made from the material of the ^{9 × 10 -6 / K~12 × 10} -6 / K. That is, the linear expansion coefficient α _H [unit: 10 ⁻⁶ / K] of the material constituting the heater 14 (the material of the sheath tube in contact with the base material 12) is (α ₁ -4) ≦ α
It is preferable that _H ≦ (α ₁ +4) is satisfied. The linear expansion coefficient of the main body of the heater 14 is not particularly limited since it does not affect the base mounting stage 10.

The pipe 15 is connected to a heating medium supply device (reference numeral 40 in FIG. 2), and is made of a metal or an alloy. By flowing the heat medium supplied from the heat medium supply device 40 to the pipe 15 in the substrate mounting stage 10, the temperature of the substrate mounting stage 10 can be controlled. The thermal expansion of the pipe 15 also affects the substrate mounting stage 10. Therefore, it is preferable to use a material having values close to the linear expansion coefficients α ₁ and α ₂ of the base material 12 and the ceramic layer 13. Specifically, titanium, stainless steel, etc.
It is preferable to use a pipe 15 made of a material having a linear expansion coefficient of 9 × 10 ⁻⁶ / K to 12 × 10 ⁻⁶ / K. That is,
Linear expansion coefficient α _P of the material constituting the pipe 15 [Unit: 10 ^-6]
/ K] preferably satisfies (α ₁ -4) ≦ α _P ≦ (α ₁ +4).

The substrate mounting stage 10 having such a configuration
A DC voltage is applied to the (more specifically, the base material 12) via wiring (not shown). Therefore, by using the substrate mounting stage 10 as an electrode, the ceramic layer 13 functions as an electrostatic chuck. A pusher pin (not shown) for pushing up a base (for example, a silicon semiconductor substrate) mounted and held on the ceramic layer 13 is embedded in the base mounting stage 10.
The pusher pin is provided with a mechanism (not shown) for projecting the pusher pin above the top surface of the ceramic layer 13 or burying the pusher pin below the top surface.

The above-described substrate mounting stage is, for example, shown in FIG.
Can be used by being incorporated in a plasma etching apparatus 20 shown in FIG. This plasma etching apparatus 20
It is roughly divided into a plasma generation unit that generates helicon wave plasma using two types of RF antennas, and a processing unit that performs plasma etching using the generated helicon wave plasma.

The plasma generating unit is, for example, a plasma vessel 21 composed of a cylindrical quartz tube having a diameter of 35 cm, and is provided around the plasma vessel 21 and has a double loop having two loops for coupling RF power to plasma. Loop antenna 22, this double loop antenna 22
A solenoid coil assembly 23 orbiting the plasma container 21 further outside, a top plate 24 made of a non-conductive material closing the upper end of the plasma container 21, and a single plate outside the plasma container 21 in a plane parallel to the top plate 24. A single loop antenna 25 forming a loop is provided. The solenoid coil assembly 23 generates a magnetic field along the axial direction of the plasma container 21, and includes an inner peripheral coil 23 </ b> A mainly contributing to helicon wave propagation and an outer peripheral coil 23 </ b> B mainly contributing to helicon wave plasma transport. Become.

The two loops of the double-loop antenna 22 are separated by a distance corresponding to about 約 of the wavelength of the helicon wave to be propagated, and their winding directions with respect to the plasma container 21 are reversed. . RF power is supplied to the double-loop antenna 22 from the first RF power supply 27 via the matching network 26 for impedance matching, whereby m = 0 mode helicon wave plasma is excited inside the plasma container 21. You.
In addition, a single loop antenna 25 receives an RF signal from a second RF power source 29 via a matching network 28.
Power is supplied, and thereby the helicon wave plasma of m = 0 mode is excited inside the plasma container 21.
These two antennas generate two types of helicon wave plasmas having slightly different saturated ion current density distributions in the plasma container 21.

As described above, when the single-loop antenna 25 and the double-loop antenna 22 are independently connected to the first RF power supply 27 and the second RF power supply 29,
A desired saturated ion current density distribution can be created in the plasma container 21 by simultaneously exciting two types of helicon wave plasmas, or continuously exciting one of them and intermittently exciting the other. Alternatively, a relay circuit for connecting the single-loop antenna 25 and the double-loop antenna 22 to a common RF power source and shifting the phase by 2 / π between one of the antennas and the RF power source is provided. By intervening, two types of plasma can be excited alternately while avoiding interference. further,
Plasma container 21 instead of double loop antenna 22
If a half-turn antenna is arranged to make a half turn around, the m = 1 mode helicon wave plasma can be excited. A desired saturated ion current density distribution can also be created by using the helicon wave plasma in the m = 1 mode and the m = 0 mode in combination.

On the other hand, the processing section includes a processing chamber 30 connected to the lower end of the plasma container 21 and a processing chamber 30.
Substrate mounting stage 10, electrically insulated from the wall of
A multi-pole magnet 31 is provided around the processing chamber 30 outside the processing chamber 30. The multipole magnet 31 has a function of generating a multi-cusp magnetic field and confining the plasma in order to converge a divergent magnetic field in the vicinity of the substrate mounting stage 10 and to suppress annihilation of electrons and active species in the plasma due to a chamber wall. Having. The position of the multipole magnet 31 is not limited to the illustrated example.
Other places, such as around the pillars. Or,
This may be replaced by a solenoid coil for forming a mirror magnetic field. The processing chamber 30 has an exhaust port 32, and the exhaust port 32 is connected to negative pressure means (not shown) such as a vacuum pump. In FIG. 2, details of an etching apparatus such as an etching gas introduction unit and a gate valve are not shown.

Base material 12 constituting base mounting stage 10
The bias power supply 34 has a matching network 3
3 are connected. This bias power supply 34
It has a function of applying a substrate bias to the silicon semiconductor substrate 50 in order to control the energy of ions incident from the plasma. The top plate 24 plays the role of the opposite ground electrode with respect to the substrate bias. Furthermore, a DC power supply 35 for exerting an electrostatic attraction force on the ceramic layer 13 as a dielectric member is connected. Further, the heater 14 of the substrate mounting stage 10 is connected to a power supply 36. A fluorescent fiber thermometer 37 for measuring the temperature of the silicon semiconductor substrate 50 is inserted through the center of the base mounting stage 10. Based on the temperature detected by the fluorescent fiber thermometer 37, the control device (PID controller) 38 determines the amount of power to the heater 14 and sends an output control signal to the power supply 36, whereby the substrate mounting stage 1
Zero temperature control is performed.

The piping 15 provided in the base material 12 of the base mounting stage 10 is connected to a heating medium supply device 40 for temperature control via pipings 39A and 39B. The heat medium supply device 40 supplies a heat medium such as silicon oil or fluorocarbon to the base stage 10 through a pipe 39A.
And receives the heat medium sent out from the pipe 15 through the pipe 39B, and further heats or cools the heat medium to a predetermined temperature. In some cases, a chiller is incorporated in the heat medium supply device 40, and the piping 39A, 1
A low-temperature (for example, 0 ° C. or lower) heat medium (refrigerant) may be allowed to flow in 5, 39B. In this way, by circulating the heat medium in the pipe 15, the temperature of the silicon semiconductor substrate 50 as the base held and fixed on the base mounting stage 10 is controlled. A control valve 41 capable of operating at a high temperature or a low temperature is provided in a pipe 39A connected to the heat medium supply device 40. On the other hand, the pipe 39A and the pipe 3
A control valve 41 is also provided in the bypass pipe 39C between the control valve 41 and the control valve 9B. Then, under such a configuration, by controlling the opening / closing degree of the control valve 41, the piping 15
To control the amount of heat medium supplied to the heater. Further, the temperature detected by the fluorescent fiber thermometer 37 is detected by the control device (PID controller) 38, and the difference between the temperature of the silicon semiconductor substrate 50 and the supply amount determined by experiments and calculations in advance is determined. Thus, the supply amount of the heat medium is determined by the control device 38.

In the substrate mounting stage 10 shown in FIG. 1A, a silicon semiconductor substrate 50 as a substrate is provided.
Energizing the heater 14 or piping 15
The main temperature control is performed through heating by flowing a high-temperature heat medium through the heater or cooling by flowing a low-temperature heat medium (refrigerant) through the pipe 15. When performing rapid temperature rise and fall between etching processes, only one of heating and cooling is performed. When maintaining the temperature of the substrate mounting stage 10 during etching, only one of heating and cooling may be performed, or both heating and cooling may be performed. The maintenance of the set temperature during etching is preferably controlled in real time by feedback control or feedforward control.

Hereinafter, a process of actually forming a gate electrode of a dual gate type CMOS according to the above-mentioned method (i) using the above-described plasma etching apparatus will be described with reference to FIGS. Here, an example will be described in which a silicon semiconductor substrate 50 is used as a base, a gate oxide film 53 is used as a gate insulating film, a polymetal film 57A is used as a layer to be processed, and a composite mask 60 is used as an etching mask. The polymetal film 57A is composed of a polysilicon layer 54 as a silicon-based material layer, a titanium nitride layer 55 as a barrier layer, and a tungsten layer 56 as a metal layer. The composite mask 60 includes a silicon nitride layer 58 which is an inorganic compound layer and an organic resist layer 59.

[Step-100] First, the element isolation region 5 is formed on the silicon semiconductor substrate 50 by, for example, the LOCOS method.
Form one. Note that the element isolation region 51 may have a trench structure. Next, an n-type impurity is introduced into the silicon semiconductor substrate 50 in the PMOS formation region and a p-type impurity is introduced into the silicon semiconductor substrate 50 in the NMOS formation region, for example, by ion implantation, and activation annealing (drive-in) is performed. Through the n-type well 52n and the p-type well 52
Form p. Next, the surface of the silicon semiconductor substrate 50 is oxidized by, for example, a pyrogenic method to form a gate oxide film 53 with a thickness of about 2.5 nm. Next, a polysilicon layer 54 is formed on the entire surface to a thickness of about 70 nm by a CVD method, for example.
Film is formed to a thickness of Next, a p-type impurity is introduced into the polysilicon layer 54 in the PMOS formation region, and an n-type impurity is introduced into the polysilicon layer 54 in the NMOS formation region, for example, by an ion implantation method. Next, the titanium nitride layer 55 is
A film is formed on the entire surface to a thickness of about 5 nm by, for example, a sputtering method. Next, a tungsten layer 56 is coated on the entire surface with, for example, C
A film is formed to a thickness of about 100 nm by the VD method. The polysilicon layer 54, the titanium nitride layer 55, and the tungsten layer 56 form a polymetal film 57A. A silicon nitride layer 58 is formed on the polymetal film 57A.
Is formed on the entire surface to a thickness of about 200 nm by, for example, a sputtering method. Next, an organic resist layer 59 is formed on the entire surface, and the organic resist layer 59 is patterned through ordinary photolithography and development steps. Further, using the organic resist layer 59 as an etching mask, the silicon nitride layer 58 is etched by, for example, plasma etching using SF ₆ gas. The organic resist layer 59 and the silicon nitride layer 58 thus patterned form a composite mask 60. The line width of the composite mask 60 is about 1.3 μm. FIG. 3A shows a state in which the process up to this point has been completed.

[Step-110] Next, the silicon semiconductor substrate 50 is mounted on the substrate mounting stage 10 in the etching apparatus 20 shown in FIG. The semiconductor substrate 50 is held and fixed on the base mounting stage 10. Then, while controlling the temperature of the base mounting stage 10 mainly by the refrigerant,
The portion of the tungsten layer 56 exposed from the composite mask 60 is etched by plasma etching under the conditions shown in Table 1 below as an example. When the temperature of the substrate mounting stage 10 is lower than the target temperature by the refrigerant, the heater 14 is operated to increase the temperature. Fluorine-based etching gas used herein is an SF _6. This etching proceeds anisotropically by so-called low-temperature etching, as shown in FIG.

[Table 1] Etching gas: SF ₆ = 20 sccm Pressure: 0.5 Pa (4 mTorr) RF power (single loop antenna): 1.5 kW (13.56 MHz) RF power (double loop antenna): 1 kW ( 13.56 MHz) RF bias power: 0.1 kW (400 kHz) Temperature of substrate mounting stage: -20 ° C

[Step-120] Next, the circulation of the refrigerant is stopped, and the heater 14 is operated to raise the temperature of the substrate mounting stage 10 to room temperature (25 ° C.). The heating rate at this time can be set to about 100 ° C./min. Then, the temperature of the substrate mounting stage 10 is set to 25 ° C.
The portion of the titanium nitride layer 55 exposed from the composite mask 60 and the polysilicon layer 5 appearing therebelow.
The portion 4 is etched by plasma etching under the conditions shown in Table 2 below as an example. The chlorine-based etching gas used here is a mixed gas of Cl ₂ and O ₂ .

[Table 2] Etching gas: Cl ₂ / O ₂ = 40/10 sccm Pressure: 1 Pa (8 mTorr) RF power (single loop antenna): 1.5 kW (13.56 MHz) RF power (double loop antenna) : 1 kW (13.56 MHz) RF bias power: 20 W (400 kHz) Temperature of substrate mounting stage: 25 ° C

In the etching of [Step-120], the n-type and p-type polysilicon layers 54 having different etching characteristics are simultaneously etched following the removal of the titanium nitride layer 55, but the etching is performed at around room temperature. In addition, it is difficult for the difference in etching rate due to the difference in conductivity type to become apparent. Therefore, as shown in FIG. 4A, in both the PMOS formation region and the NMOS formation region of the dual gate CMOS, the gate electrode 61A can be formed simultaneously and with high accuracy. Also, [Process-
110] and [Step-120], there is a difference of 45 ° C. in the temperature of the substrate mounting stage.
In the substrate mounting stage 10 of the present invention in which the coefficient of linear expansion is defined as described above, generation of cracks in the dielectric member is prevented. Therefore, it is possible to continuously perform etching processes having different temperatures in a single plasma chamber.

[Step-130] Thereafter, as shown in FIG. 4B, the organic resist layer 59 is removed by, for example, ashing. Although the silicon nitride film 58 remains on the gate electrode 61A, the silicon nitride layer 58 can be used as a part of an insulating layer covering the gate electrode 61A. When a self-aligned contact process is performed in a later step, the silicon nitride layer 58 also serves as an etching stop layer when opening a hole in the insulating layer.

In the first embodiment, a tungsten nitride layer may be used as the barrier layer instead of the titanium nitride layer 55. In this case, [Step-11
0], the tungsten layer 56 is etched using a fluorine-based etching gas, and then the tungsten nitride layer can be etched by continuing the etching under the same conditions.

(Embodiment 2) Embodiment 2 is a modification of Embodiment 1 and uses the above-described plasma etching apparatus 20 to actually form a gate electrode of a dual gate type CMOS according to the above-described method (ii). The process of forming This process will be described with reference to FIGS. Detailed description of portions common to the first embodiment is omitted.

[Step-200] First, an element isolation region 51 is formed in a silicon semiconductor substrate 50, and a well 52 is formed.
After the formation of p, 52n, the formation of the gate oxide film 53, and the formation of the polysilicon layer 54 are performed in the same manner as in the first embodiment, a tungsten nitride layer 62 is formed as a barrier layer on the entire surface to a thickness of about 5 nm by, for example, a sputtering method. The film is formed to a thickness.
Next, a tungsten layer 56 is formed to a thickness of about 100 nm over the entire surface by, for example, a CVD method. The polysilicon layer 54, the tungsten nitride layer 62, and the tungsten layer 56 form a polymetal film 57B. The composite mask 60 is formed on the polymetal film 57B as in the first embodiment. FIG. 5A shows a state in which the processes up to this point have been completed.

[Step-210] Next, the silicon semiconductor substrate 50 is mounted on the substrate mounting stage 10 in the etching apparatus 20 shown in FIG. The semiconductor substrate 50 is held and fixed on the base mounting stage 10. Then, while controlling the temperature of the substrate mounting stage 10 by the heater 14, the portion of the tungsten layer 56 exposed from the composite mask 60,
The tungsten nitride layer 62 appearing thereunder is etched by plasma etching under the conditions shown in Table 3 below as an example. When the temperature of the substrate mounting stage 10 rises above the target temperature by the heater 14, the coolant is circulated to lower the temperature. The chlorine-based etching gas used here is a mixed gas of Cl ₂ and O ₂ . This etching proceeds anisotropically, as shown in FIG.

[Table 3] Etching gas: Cl ₂ / O ₂ = 40/10 sccm Pressure: 0.5 Pa (4 mTorr) RF power (single loop antenna): 1.5 kW (13.56 MHz) RF power (double loop Antenna): 1 kW (13.56 MHz) RF bias power: 0.1 kW (400 kHz) Temperature of substrate mounting stage: 100 ° C

[Step-220] Next, the power supply to the heater 14 is stopped, and the refrigerant is circulated through the pipe 15 so that
The temperature of the substrate mounting stage 10 is lowered to room temperature (25 ° C.). At this time, the temperature decreasing rate can be about 100 ° C./min. Then, while controlling the temperature of the substrate mounting stage 10 to 25 ° C., the portion of the polysilicon layer 54 exposed from the composite mask
Etching is performed under the conditions shown in FIG. As a result, as shown in FIG. 6, a gate electrode 61B having a good anisotropic shape can be formed in both the PMOS formation region and the NMOS formation region.

(Embodiment 3) An outline of a method of manufacturing the substrate mounting stage 10 (see FIG. 1A) used in Embodiments 1 and 2 will be described below.

The composite member 11 comprises (A) a step of filling a structure of a ceramic member with an aluminum-based material, thereby producing a base material in which the structure of the ceramic member is filled with an aluminum-based material; ) It is produced from the step of providing a ceramic layer on the surface of the base material. In the third embodiment, in this step (A), a ceramic member composed of porous cordierite ceramics is disposed in a container (mold), and molten aluminum and silicon are contained in the container (mold). Pour an aluminum-based material with a composition of
The method comprises a step of filling an aluminum-based material into a ceramic member by high-pressure casting.

A ceramic member made of a porous cordierite ceramic is made porous in a sintering process when the ceramic member is manufactured. In the third embodiment, a porous cordierite ceramic fiber board which is a sintered body obtained by sintering cordierite ceramic powder and cordierite ceramic fiber is used as the porous cordierite ceramic. (Hereinafter, abbreviated as a fiber board). Whereas general powder sintered ceramics are sintered at a high temperature of about 1200 ° C, fiberboard is about 800 ° C.
The cordierite ceramic powder is sintered so as to adhere tightly around a cordierite ceramic fiber via a binder, and is made porous. Therefore, for example, by changing the volume ratio between cordierite ceramic powder and cordierite ceramic fibers, the porosity and pore diameter of the resulting ceramic member having a porous cordierite ceramic composition can be adjusted. Is possible.

In order to manufacture the substrate mounting stage 10, first, a first fiber board formed into a predetermined disk shape is prepared. In addition, a groove for disposing the heater 14 is formed in the first fiber board. Also, the first
A second fiber board different from the above fiber board is prepared. This second fiber board has a pipe 15
The groove for arranging is processed. Then, the first fiber board is arranged on the bottom of the container (mold), and the heater 14 is arranged in a groove provided in the first fiber board. Next, the second fiber board is placed on the first fiber board, and the pipe 15 is arranged in a groove provided in the second fiber board. Then, a third fiber board is placed on the second fiber board. In addition, holes for embedding pusher pins and the like are formed in these fiber boards in advance.

Next, the ceramic member made of the fiber board is preheated to about 800 ° C., and then heated to about 800 ° C. in a container (mold) to obtain an aluminum-based material (in a molten state). Al 80% by volume-
(20% by volume of Si). Then, a high-pressure casting method in which a high pressure of about 1 ton / cm ² is applied in the container (mold) is performed. As a result, a porous fiber board
The structure of the ceramic member is filled with an aluminum-based material. Then, the base material 12 is produced by cooling and solidifying the aluminum-based material.

Next, the top surface of the base material 12, that is, the surface on the heater side is polished. Then, T on the polished surface, the Al ₂ O ₃
A mixed powder having a particle diameter of about 10 μm in which about 2.5% by weight of iO ₂ is mixed is sprayed in a molten state by a vacuum spraying method to be solidified. As a result, the volume resistivity value is 10 ¹¹ Ω / □
The ceramic layer 13 having a thickness of the order of about 0.2 mm can be formed by a thermal spraying method. The ceramic layer 1
Prior to the formation of the thermal spraying layer 3, for example, nickel (Ni-5% by weight Al) containing about 5% by weight of aluminum is sprayed as a thermal spraying underlayer, and a ceramic layer 13 is formed on the thermal spraying underlayer.
May be formed by a thermal spraying method.

In order to confirm the effect of preventing the ceramic layer 13 of the substrate mounting stage 10 thus obtained from cracking, a hot air circulating oven was used to heat the substrate mounting stage 10 as follows. A cycle test was performed.

(1) The substrate mounting stage 10 is placed in an oven, and the inside of the oven is heated to 300 ° C. over 30 minutes. (2) Hold the inside of the oven at a temperature of 300 ° C. for 20 minutes. (3) The temperature in the oven is lowered over 40 minutes to return to room temperature. (4) Take out the substrate mounting stage 10 from the oven and observe the appearance.

When the operations (1) to (4) were repeated 10 times, no change was observed in the appearance of the substrate mounting stage 10 even after the completion of the operation 10 times, and cracks and the like were found on the ceramic layer 13. It was confirmed that no damage occurred.

The substrate mounting stage 10 obtained as described above is made of a ceramic member made of porous cordierite ceramic fiber board, and is provided with 80% by volume of Al.
-Si20 volume percent of aluminum-based material preform obtained by filling the is constituted by (temperature regulating jacket) 12, the linear expansion coefficient alpha ₁ of the matrix 12 ceramic layer 13
Has a value close to the coefficient of linear expansion α ₂ . Therefore, the degree of expansion and contraction of the base material 12 and the ceramic layer 13 due to heating and cooling of the base mounting stage 10 is almost the same. Therefore,
Due to the difference between the linear expansion coefficients α ₁ and α ₂ between these materials, damages such as cracks occur in the ceramic layer 13 at the time of high-temperature heating or when the temperature of the substrate mounting stage 10 is rapidly raised and lowered. Can be reliably avoided.

In the third embodiment, a porous cordierite ceramic fiber board is used. The board is tolerable. As a result, the occurrence of cracks in the fiber board can be suppressed. That is, in a ceramic member made of porous cordierite ceramic obtained by a normal powder sintering method, cracks are likely to occur during high-pressure casting. However, by using a porous cordierite ceramic fiberboard, it is possible to suppress the occurrence of cracks in the ceramic member during high-pressure casting.

Further, since it is possible to avoid the occurrence of cracks and the like in the fiber board during high-pressure casting, it is possible to more reliably prevent the ceramic layer 13 provided on the surface of the base material 12 from being damaged by cracks and the like. it can. That is, even if a crack occurs in the fiber board, when the structure of the ceramic member made of the fiber board is filled with the aluminum-based material, the aluminum-based material acts as a kind of adhesive, so that the base material 12 can be obtained. . However, the thus obtained base material 12
In this case, a layer made of an aluminum-based material is formed in gaps such as cracks generated in the fiber board.
As a result, the ceramic layer 13 provided on the surface of the base material 12 cannot follow the temperature change when the base mounting stage 10 is used, and the ceramic layer 13 is easily cracked. That is, the ceramic layer 13 has a particle size of about 10 μm.
Since the mixed powder of m is sprayed and assimilated with the base material 12, it is hardly affected by the thermal expansion of the aluminum-based material itself filled in the pores of 1 to 2 μm in the fiberboard. However, the layer made of the aluminum-based material existing in the gap between the cracked portions of the fiber board has a length and a width larger than the diameter of the particles forming the ceramic layer 13. Therefore, the ceramic layer 13 due to the thermal expansion of such a layer made of an aluminum-based material
The effect on the ceramic layer becomes significant and cannot be ignored.
The probability that cracks will occur in 3 increases.

Further, since the ceramic layer 13 is formed on the base material 12 by the thermal spraying method, the base material 12 and the ceramic layer 1 are formed.
3 is further integrated. Thereby, stress relaxation between the base material 12 and the ceramic layer 13 can be achieved,
The heat conduction from the base material 12 to the ceramic layer 13 becomes faster, and the temperature of the base (for example, a silicon semiconductor substrate) held and fixed to the ceramic layer 13 can be quickly and reliably controlled.

(Embodiment 4) Embodiment 4 is a modification of Embodiment 3. Embodiment 4 is different from Embodiment 3 in that the composition of the ceramic member forming the base material in the composite member is aluminum nitride (TiN), and the composition of the aluminum-based material forming the base material is aluminum (Al). It is in the point which was. The structure of the base mounting stage 10A in the fourth embodiment is shown in a schematic cross-sectional view in FIG.

In the fourth embodiment, the composition of the ceramic member forming base material 12 is aluminum nitride (Al
N). The coefficient of linear expansion of aluminum nitride is 5.1.
× 10 ^-6 / K and thermal conductivity of 0.235 cal / c
m · sec · K. The composition of the aluminum-based material constituting the base material was aluminum (Al). (Α ₁ −
4) The volume ratio between aluminum nitride and aluminum is determined so as to satisfy the relationship of ≦ α ₂ ≦ (α ₁ +4), and specifically, the volume ratio of aluminum nitride / aluminum is 70/30. . The linear expansion coefficient of the base material 12 is
8.7 × 10 ⁻⁶ / average value at 100 to 300 ° C.
K. That is, α ₁ is 8.7. The material constituting the ceramic layer 13 was Al ₂ O ₃ to which about 2.5% by weight of TiO ₂ was added. The ceramic layer 13 is formed on the surface of the base material 12 by a thermal spraying method. Ti to Al ₂ O ₃
By adding O ₂ , the coefficient of linear expansion becomes 100
About 9 × 10 ^-6 / K (α ₂
= About 9), and substantially the same value as the linear expansion coefficient alpha ₁ of the matrix 12. Accordingly, it is possible to effectively prevent the ceramic layer 13 from being damaged by cracks or the like due to a temperature change due to high-temperature heating of the base material 12 or the like. Also, Al ₂ O ₃
By adding TiO ₂ to the ceramic layer 13
Can be adjusted to the order of 10 ¹¹ Ω / □. Thereby, the ceramic layer 13 effectively exerts a function as an electrostatic chuck. That is, if a DC voltage is applied from a power supply to the base material 12 of the base mounting stage 10A via wiring (not shown), the base material 12 can be used as an electrode, and the ceramic layer 13 functions as an electrostatic chuck. I do. The substrate mounting stage 10
A is embedded with a pusher pin (not shown) for pushing up, for example, a silicon semiconductor substrate placed and held on the ceramic layer 13. The pusher pin is provided with a mechanism (not shown) for projecting the pusher pin above the top surface of the ceramic layer 13 or burying the pusher pin below the top surface.

The heater 14A in the fourth embodiment is a PBN heater (pyrolytic boron nitride pyrolytic heater) capable of heating up to about 500 ° C.
(Graphite heater). Heater 14A as base material 1
By attaching the base material 12 to the outside surface of the base material 2, the temperature of the base material 12 can be controlled within a range from room temperature to about 500 ° C.

A method for manufacturing the base mounting stage 10A constituted by the composite member 11 will be described below. The composite member 11 is basically (A) a step of filling a structure of a ceramic member with an aluminum-based material, thereby producing a base material in which the structure of the ceramic member is filled with an aluminum-based material; (B) It is produced from the step of providing a ceramic layer on the surface of the base material. In the fourth embodiment,
This step (A) includes a step of infiltrating a ceramic material formed from aluminum nitride particles with an aluminum-based material containing molten aluminum in a non-pressurized state based on a non-pressurized metal permeation method.

Specifically, AlN particles having an average particle size of 10 μm are formed by a slurry casting method,
By performing firing (sintering) at the temperature described above, a ceramic member as a preform formed of AlN particles was produced. Then, the ceramic member is preheated to about 800 ° C., and the aluminum melted by heating to about 800 ° C. is infiltrated into the ceramic member without pressure.
Thereby, the base material 12 having a configuration of 70% by volume of AlN-30% by volume of Al can be manufactured. Then, the base material 1
2 is formed into a disk shape. Next, the top and side surfaces of the base material 12 thus obtained are polished. Thereafter, a mixed powder of about 2.5% by weight of TiO ₂ mixed with Al ₂ O ₃ having a particle size of about 10 μm is sprayed onto the polished surface in a molten state by a vacuum spraying method to be solidified. Thereafter, a heater 14A made of a PBN heater is attached to the lower surface of the base material 12, that is, the surface opposite to the surface on which the ceramic layer 13 is provided, to obtain the substrate mounting stage 10A. Prior to the formation of the ceramic layer 13, for example, nickel containing approximately 5% by weight of aluminum (Ni-5% by weight
1) may be sprayed, and the ceramic layer 13 may be formed on the sprayed underlayer by a spraying method.

In the substrate mounting stage 10A thus manufactured, the coefficient of linear expansion α of the ceramics layer 13 is
₂ is almost the same value as the linear expansion coefficient α ₁ of the base material 12.
Therefore, even if the base material 12 changes in temperature due to high-temperature heating or the like, the ceramic layer 13 is not damaged such as a crack. Further, by adjusting the volume ratio between aluminum nitride and aluminum, and further, if necessary,
By adjusting the addition rate of TiO ₂ in the ceramic layer 13 made of ₂ O _3, the linear expansion coefficient α _{1 of the} base material 12 is adjusted.
And the coefficient of linear expansion α ₂ of the ceramic layer 13 is defined as (α ₁ -4) ≦
The relationship may satisfy the relationship α ₂ ≦ (α ₁ +4). As a result, it is possible to effectively prevent damage such as cracking of the ceramic layer 13 due to a temperature change of the base mounting stage 10A.

Further, if the ceramic layer 13 is formed on the base material 12 by a thermal spraying method, a large-area composite member can be manufactured, and it is possible to easily cope with an increase in the area of the base. Moreover, the base material 12 and the ceramic layer 13 are further integrated. Thereby, the stress between the base material 12 and the ceramic layer 13 can be relaxed, and the heat conduction from the base material 12 to the ceramic layer 13 can be quickly performed. In addition, as shown in FIG. 7B, a ceramic layer may be formed on the side surface of the base material 12 as necessary.

As shown in the schematic cross-sectional view of FIG. 1B, the ceramic layer may be provided on the surface (and, if necessary, the side surface) of the base material 12 by a brazing method instead of a thermal spraying method. Good (see FIG. 7C). In this case, the ceramic layer 16 made of an Al ₂ O ₃ ceramic plate manufactured by the sintering method is applied to the ceramic layer 16 at a temperature of, for example, about 600 ° C.
It may be attached to the surface of the base material 12 by a brazing method using a l-Mg-Ge brazing material 17. If necessary, an annular cover (not shown) made of a ceramic material may be attached to the side surface of the base material 12. Embodiment 3
The temperature control means may be the same as that of the substrate mounting stage 10 in the above.

Although the composition of the aluminum-based material forming the base material was aluminum, the composition of the aluminum-based material forming the base material was changed to aluminum and silicon (for example, 80% by volume of Al—20% by volume of Si). It can be. By the composition of the aluminum-based material and aluminum and silicon, it is possible to control the alpha ₁ the linear expansion coefficient of the base material, it is possible to reduce the difference more linear expansion ratio alpha ₂ of the ceramic layer Become.
Further, instead of forming the ceramic layer from Al ₂ O ₃ , the ceramic layer may be formed from aluminum nitride (AlN).

The structure of the substrate mounting stage described in the fourth embodiment can be applied to the substrate mounting stage described in the third embodiment, or the substrate mounting stage described in the third embodiment can be applied. The structure of the mounting stage can be applied to the base mounting stage described in the fourth embodiment.

(Fifth Embodiment) The fifth embodiment is a modification of the fourth embodiment. Embodiment 5 is different from Embodiment 4 in that the composition of the ceramic member forming the base material in the composite member is silicon carbide (SiC), and the composition of the aluminum-based material forming the base material is aluminum (Al).
It is in the point which was. The structure of the base mounting stage 10A in the fifth embodiment is the same as that shown in the schematic cross-sectional view of FIG.

In the fifth embodiment, the composition of the ceramic member forming base material 12 is silicon carbide (SiC). The linear expansion coefficient of silicon carbide is 4 × 10 ⁻⁶ / K, and the thermal conductivity is 0.358 cal / cm · sec · K (15
0 W / m · K). The composition of the aluminum-based material constituting the base material was aluminum (Al). (Α
_{1 -4) ≦ α 2 ≦ (} α 1 +4) the volume ratio of silicon carbide and aluminum so as to satisfy is determined, specifically, the volume ratio of silicon carbide / aluminum 70/30
It is. The coefficient of linear expansion of the base material 12 is 6.2 × 10 ⁻⁶ / K as an average value at 100 to 300 ° C. That is, α ₁ = 6.2. The material constituting the ceramic layer 13 is Al ₂ O to which about 1.5% by weight of TiO ₂ is added.
_{It was set to 3} . The ceramic layer 13 is formed by spraying the base material 12
Are formed on the top surface and the side surfaces. Al ₂ O ₃ is originally the linear expansion coefficient of about 8 × 10 ^-6 / K, Ti to Al ₂ O ₃
By adding O ₂ , the coefficient of linear expansion becomes 100
About 8 to 9 × 10 ⁻⁶ / K at an average value of about 300 ° C.
(The alpha ₂ about 8-9), and the relation between the linear expansion coefficient alpha ₂ of the linear expansion coefficient alpha ₁ and the ceramic layer 13 of the matrix 12, (alpha ₁ -4)
≦ α ₂ ≦ (α ₁ +4). Thereby, the base material 1
2, it is possible to effectively prevent the ceramic layer 13 from being damaged such as a crack due to a temperature change due to high-temperature heating or the like. Further, by adding TiO ₂ to Al ₂ O ₃ , the volume resistivity of the ceramic layer 13 is set to 10 ¹¹ Ω /
Can be adjusted to the order of □. by this,
The ceramic layer 13 effectively exhibits a function as an electrostatic chuck.

The heater 14A is provided in the same manner as in the fourth embodiment.
It is a PBN heater. By attaching the heater 14A to the back surface of the temperature control jacket, which is the base material 12, it is possible to control the temperature of the base material 12 from room temperature to about 500 ° C. Alternatively, a temperature control unit similar to that of the substrate mounting stage in the third embodiment can be used. When a DC voltage is applied to the base material 12 of the base mounting stage 10A via wiring (not shown), the base material 12 can be used as an electrode, and the ceramic layer 1
3 functions as an electrostatic chuck. A pusher pin (not shown) for pushing up, for example, a silicon semiconductor substrate mounted and held on the ceramic layer 13 is embedded in the base mounting stage 10A. The pusher pin is provided with a mechanism (not shown) for projecting the pusher pin above the top surface of the ceramic layer 13 or burying the pusher pin below the top surface.

The method of manufacturing the substrate mounting stage 10A will be described below. The composite member 11 is basically (A) a step of filling a structure of a ceramic member with an aluminum-based material, thereby producing a base material in which the structure of the ceramic member is filled with an aluminum-based material; (B) It is produced from the step of providing a ceramic layer on the surface of the base material. In the fifth embodiment, this step (A) is based on a non-pressurized metal infiltration method, in which a ceramic member molded from silicon carbide particles is subjected to a non-pressurized aluminum-based material in a non-pressurized state. Permeation step.

Specifically, SiC particles having an average particle size of 15 μm
And SiC particles having an average particle diameter of 60 μm in a volume ratio of 1: 4.
After shaping the mixture mixed in with the casting slurry forming method,
By firing at a temperature of about 800 ° C., the SiC
A ceramic member, which is a preform formed from particles,
Produced. And about 800 mm
Preheat to C, heat to about 800 ° C and melt
Aluminum that has passed through the ceramic member without pressure
You. Thereby, SiC 70 volume% -Al 30 volume%
Can be manufactured. Then mother
Material 12 is shaped and shaped into a disc-shaped temperature control jacket
State. A pusher pin or the like is attached to the base material 12.
Holes for embedding are also processed in advance. Then this
The top surface of the base material 12 thus obtained is polished. afterwards,
On this polished surface, Al_TwoO_ThreeTiO2 _TwoAbout 1.5% by weight
The mixed powder having a combined particle size of about 10 μm is
Spray in a molten state to solidify. This allows the body
Product specific resistance value is 10¹¹Ω / □ thickness about 0.2m
m ceramic layers 13 can be formed. That
Thereafter, the bottom surface of the base material 12, that is, the ceramic layer 13 is provided.
Heater 1 consisting of a PBN heater on the surface opposite to the top surface
4A is attached to obtain a substrate mounting stage 10A. still,
Before forming the ceramics layer 13
For example, nickel containing about 5% by weight of aluminum (Ni-
5% by weight of Al), and the thermal spray
The lamix layer 13 may be formed by a thermal spray method.

Note that the method of manufacturing the substrate mounting stage 10A is not limited to the above-described method. The above step (A)
As in Embodiment 3, a ceramic member composed of silicon carbide is placed in a container (mold), and an aluminum-based material composed of molten aluminum is poured into the container (mold). And filling the ceramic member with an aluminum-based material. That is, to manufacture the substrate mounting stage 10A, first, a preform made of SiC molded into a predetermined disk shape is prepared. A hole for embedding a pusher pin or the like is formed in the preform in advance. Next, the ceramic member made of the preform is preheated to about 800 ° C., and subsequently, molten aluminum is poured into the vessel (mold) by heating to about 800 ° C. Then, a high-pressure casting method in which a high pressure of about 1 ton / cm ² is applied in the container (mold) is performed. As a result, the structure of the ceramic member is filled with aluminum. Then, the base material 12 is manufactured by cooling and solidifying the aluminum. Hereinafter, the substrate mounting stage 10A may be manufactured by the same method as described above.

In the substrate mounting stage 10A manufactured as described above, the ceramic layer 13 does not suffer damage such as cracks even when the base material 12 changes in temperature due to high-temperature heating or the like. Further, by adjusting the volume ratio between silicon carbide and the aluminum-based material, and further, if necessary, the T _{2 in the} ceramic layer 13 made of Al ₂ O ₃ may be adjusted.
By adjusting the addition rate of the iO _2, linear expansion coefficient alpha ₂ of the linear expansion coefficient alpha ₁ and the ceramic layer 13 of the preform 12, (alpha
_{1 -4) ≦ α 2 ≦ (} α 1 +4) can be related to satisfy. As a result, it is possible to effectively prevent damage such as cracking of the ceramic layer 13 due to a temperature change of the base mounting stage 10A.

Further, if the ceramic layer 13 is formed on the base material 12 by a thermal spraying method, a large-area composite member can be manufactured, and it is possible to easily cope with an increase in the area of the base. Moreover, the base material 12 and the ceramic layer 13 are further integrated. As a result, the stress between the base material 12 and the ceramic layer 13 can be relaxed, and the heat conduction from the base material 12 to the ceramic layer 13 can be accelerated. ) Can be quickly and reliably performed.

As shown in the schematic sectional view of FIG. 7C, the ceramic layer is provided on the top surface (and, if necessary, the side surface) of the base material 12 by a brazing method instead of a thermal spraying method. Is also good. In this case, Al ₂ produced by the sintering method
A ceramic layer 16 made of an O ₃ ceramic plate is
For example, it may be attached to the top surface of the base material by a brazing method using an Al-Mg-Ge brazing material 17 at a temperature of about 600 ° C.

Although the composition of the aluminum-based material constituting the base material was aluminum, the composition of the aluminum-based material constituting the base material was changed to aluminum and silicon (for example, 80% by volume of Al—20% by volume of Si). It can be. By setting the composition of the aluminum-based material to aluminum and silicon, the coefficient of linear expansion of the base material α
It is possible to control the _1, it is possible to reduce the difference between the linear expansion coefficient alpha ₂ of the further ceramic layer. Also, instead of forming the ceramic layer from Al ₂ O ₃ ,
It may be made of aluminum nitride (AlN).

Further, the structure of the substrate mounting stage described in the fifth embodiment can be applied to the substrate mounting stage described in the third embodiment, or the substrate mounting stage described in the third embodiment can be applied. The structure of the mounting stage can be applied to the base mounting stage described in the fifth embodiment.

(Embodiment 6) Embodiment 6 is also a modification of Embodiment 4. Embodiment 6 is different from Embodiment 4 in that the composition of the ceramic member forming the base material in the composite member is aluminum oxide (Al ₂ O ₃ ), and the composition of the aluminum-based material forming the base material is aluminum. (Al). The structure of the base mounting stage 10A in the sixth embodiment is the same as that shown in the schematic cross-sectional view of FIG.

In the sixth embodiment, the composition of the ceramic member constituting base material 12 is changed to aluminum oxide (Al
₂ O ₃ ). The linear expansion coefficient of aluminum oxide is 7.
8 × 10 ⁻⁶ / K and thermal conductivity of 0.069 cal /
cm · sec · K (29 W / m · K). The composition of the aluminum-based material constituting the base material is changed to aluminum (A
l). The volume ratio with aluminum aluminum oxide is determined so as to satisfy (α ₁ -4) ≦ α ₂ ≦ (α ₁ +4). Specifically, the volume ratio of aluminum oxide / aluminum is 80/20. is there. The coefficient of linear expansion of the base material 12 is an average value at 100 to 300 ° C.
× 10 ⁻⁶ / K. That is, α ₁ = 11. The material forming the ceramic layer 13 was Al ₂ O ₃ to which about 1.5% by weight of TiO ₂ was added. Ceramic layer 13
Are formed on the top surface and side surfaces of the base material 12 by thermal spraying. The relationship between the linear expansion coefficient alpha ₂ of the linear expansion coefficient alpha ₁ and the ceramic layer 13 of the matrix _{12, (α 1 -4) ≦ α} 2 ≦ (α 1
+4) is satisfied. Accordingly, it is possible to effectively prevent the ceramic layer 13 from being damaged by cracks or the like due to a temperature change due to high-temperature heating of the base material 12 or the like. Further, by adding TiO ₂ to Al ₂ O ₃ , the volume resistivity of the ceramic layer 13 can be adjusted to the order of 10 ¹¹ Ω / □. Thereby, the ceramic layer 13 effectively exerts a function as an electrostatic chuck.

A method of manufacturing the substrate mounting stage 10A according to the sixth embodiment will be described below. The composite member 11 is basically (A) a step of filling an aluminum-based material in the structure of a ceramic member, thereby producing a base material in which the structure of the ceramic member is filled with an aluminum-based material;
(B) It is produced from a step of providing a ceramic layer on the surface of the base material by a thermal spraying method. In the sixth embodiment, in the step (A), based on a non-pressurized metal infiltration method, an aluminum-based material containing molten aluminum is penetrated in a non-pressurized state into a ceramic member formed from aluminum oxide. The step of causing

Specifically, Al ₂ O ₃ having an average particle size of 20 μm
A mixture obtained by mixing particles and Al ₂ O ₃ particles having an average particle diameter of 80 μm at a volume ratio of 1: 4 is cast by a slurry molding method, and then baked at a temperature of about 800 ° C.
A ceramic member as a preform formed of Al ₂ O ₃ particles was produced. Then, the ceramic member is preheated to about 800 ° C., and the aluminum melted by heating to about 800 ° C. is infiltrated into the ceramic member without pressure. Thereby, Al ₂ O ₃ 80 volume% -Al
The base material 12 having a composition of 20% by volume can be manufactured.
Next, the base material 12 is formed into a shape of a disc-shaped temperature control jacket. A hole for embedding a pusher pin or the like is also formed in the base material 12 in advance. Next, the top and side surfaces of the base material 12 thus obtained are polished.

Thereafter, TiO was added to Al ₂ O ₃ on the polished surface.
₂ is mixed at about 1.5% by weight, and a mixed powder having a particle size of about 10 μm is sprayed in a molten state by a vacuum spraying method and solidified. As a result, a ceramic layer having a volume resistivity of the order of 10 ¹¹ Ω / □ can be formed by the thermal spraying method. Prior to the formation of the ceramics layer, for example, nickel (N
i-5% by weight of Al), and a ceramic layer may be formed on the thermal sprayed underlayer by a thermal spraying method. Then, a heater 1 comprising a PBN heater is provided on the bottom surface of the base material 12, that is, on the surface opposite to the top surface on which the ceramic layer 13 is provided.
4A is attached to obtain a substrate mounting stage 10A.

The method of manufacturing the substrate mounting stage 10A is not limited to the method described above. The above step (A)
As in the third embodiment, a ceramic member containing aluminum oxide is placed in a container (mold), and an aluminum-based material containing molten aluminum is poured into the container (mold). And filling the ceramic member with an aluminum-based material. That is, in order to manufacture the substrate mounting stage 10A, first, Al ₂ O ₃ formed into a predetermined disc shape is used.
A preform consisting of A hole for embedding a pusher pin or the like is formed in the preform in advance. Next, the ceramic member made of the preform is preheated to about 800 ° C., and subsequently, molten aluminum is poured into the vessel (mold) by heating to about 800 ° C. And about 1 in the container (mold)
A high pressure casting method is applied, applying a high pressure of ton / cm ² . As a result, the structure of the ceramic member is filled with aluminum. Then, the base material 12 is manufactured by cooling and solidifying the aluminum. Hereinafter, the substrate mounting stage 10A may be manufactured by the same method as described above.

In the substrate mounting stage 10A manufactured as described above, the ceramic layer 13 does not suffer damage such as cracks even when the base material 12 changes in temperature due to high-temperature heating or the like. In the substrate mounting stage according to the sixth embodiment, the volume ratio between aluminum oxide and the aluminum-based material is adjusted, and if necessary, the ceramic layer 13 made of Al ₂ O ₃ is used. By adjusting the addition rate of TiO _2, the base material 12
The linear expansion coefficient α ₁ of the ceramic layer 13 and the linear expansion coefficient α ₂ of
A relationship satisfying (α ₁ -4) ≦ α ₂ ≦ (α ₁ +4) can be established. As a result, it is possible to effectively prevent damage such as cracking of the ceramic layer 13 due to a temperature change of the base mounting stage 10A.

Further, if the ceramic layer 13 is formed on the base material 12 by a thermal spraying method, a large-area composite member can be manufactured, and it is possible to easily cope with an increase in the area of the base. In addition, since the base material 12 and the ceramic layer 13 are further integrated, stress relaxation between the base material 12 and the ceramic layer 13 can be achieved, and heat conduction from the base material 12 to the ceramic layer 13 can be promptly performed. Ceramic layer 1
The temperature control of the substrate held and fixed at 3 can be performed quickly and reliably.

Although the composition of the aluminum-based material forming the base material was aluminum, the composition of the aluminum-based material forming the base material was changed to aluminum and silicon (for example, Al 80 vol% -Si 20 vol%). It can be. By setting the composition of the aluminum-based material to aluminum and silicon, the coefficient of linear expansion of the base material α
It is possible to control the _1, it is possible to reduce the difference between the linear expansion coefficient alpha ₂ of the further ceramic layer. Also, instead of forming the ceramic layer from Al ₂ O ₃ ,
It may be made of aluminum nitride (AlN).

As shown in the schematic sectional view of FIG. 7C, a ceramic layer is provided on the top surface (and, if necessary, the side surface) of the base material 12 by a brazing method instead of a thermal spraying method. Is also good. In this case, Al ₂ produced by the sintering method
A ceramic layer 16 made of an O ₃ ceramic plate is
For example, it may be attached to the top surface of the base material by a brazing method using an Al-Mg-Ge brazing material 17 at a temperature of about 600 ° C.

The structure of the substrate mounting stage described in the sixth embodiment can be applied to the substrate mounting stage described in the third embodiment, or the substrate mounting stage described in the third embodiment can be applied. The structure of the mounting stage can be applied to the base mounting stage described in the sixth embodiment.

Although the present invention has been described based on the embodiments of the present invention, the present invention is not limited to these embodiments. FIGS. 8 to 13 show schematic cross-sectional views of a modification of the structure of the base mounting stage described in the embodiment of the present invention. In the example shown in FIG. 8A, unlike the structure shown in FIG. 1A, the heater 14 is omitted. Further, in the example shown in FIG. 8B, unlike the structure shown in FIG. 1A, the pipe 15 is omitted. still,
The structure shown in FIGS. 8A and 8B is replaced with the structure shown in FIG.
Can be applied to the substrate mounting stage shown in FIG.

In the embodiments of the present invention, the base mounting stage is manufactured exclusively from the integrally formed base material. However, the base mounting stage may be manufactured from a combination of a metal material and a base material. Can also. FIGS. 9 and 10 are schematic sectional views of such a substrate mounting stage.
The base mounting stage 10B is manufactured by fixing the composite member 11 to an aluminum or stainless steel disk-shaped member 18 by brazing or screwing.
The brazing material or screw is not shown in FIGS. 9 and 10 and FIGS. 13, 17, 20, 21 and 22 described later.

In the structure shown in FIG. 9, the top surface of base mounting stage 10B and the side surface of base mounting stage 10B are covered with ceramic layer 13. Note that, if necessary, the side surface of the base mounting stage 10B need not be covered with the ceramic layer 13. On the other hand, in the structure shown in FIG. 10, a ceramic layer 1 made of, for example, an Al ₂ O ₃ ceramic plate is provided on the top surface of the base mounting stage 10B.
6 is attached by a brazing material 17. In FIG. 9A or FIG. 10A, a pipe 15B is provided inside a disk-shaped member 18 made of aluminum. Further, the base material 12 is fixed to the upper and lower surfaces of the disk-shaped member 18. The structure of the composite member 11 fixed to the upper surface of the disk-shaped member 18 and the configuration of the base material 12 fixed to the lower surface of the disk-shaped member 18 are described in Embodiments 3 to 6.
It can be the same as the structure of the composite member and the structure of the base material described in. In FIG. 9B or FIG. 10B, the base material is omitted on the lower surface of the disc-shaped member 18 made of aluminum. In FIG. 9C or FIG. 10C, a PBN heater 14B is attached to the lower surface of a disk-shaped member 18 made of aluminum. Then, the composite member 11 is fixed to the upper surface of the disc-shaped member 18.

In the embodiment of the invention, the ceramic layer has the electrostatic chuck function (single-pole type) by using the base material of the base mounting stage as an electrode, but the electrode is provided inside the ceramic layer. By forming the ceramic layer, the ceramic layer can have a form (a bipolar type) having an electrostatic chuck function. In this case, when providing a ceramic layer on the surface of the base material by thermal spraying,
A first ceramic layer is formed on the surface of the base material by a thermal spraying method, and the electrode is formed on the first ceramic layer by a thermal spraying method, a brazing method, a plating method, or a printing method of printing and curing a conductive paste. Is preferably formed, and then the entire surface is coated with a second ceramic layer based on a thermal spraying method. Substrate mounting stage 1 having such a structure
FIG. 11A shows a schematic cross-sectional view at 0C, and FIG. 11B shows an enlarged cross-sectional view of the top end of the composite member.

More specifically, for example, in the third embodiment, after the base material 12 is manufactured, the top surface of the base material 12 is polished. Thereafter, a mixed powder of about 2.5% by weight of TiO ₂ mixed with Al ₂ O ₃ having a particle size of about 10 μm is sprayed onto the polished surface in a molten state by a vacuum spraying method to be solidified. Thereby, the first ceramics layer 130A having a volume resistivity of the order of 10 ¹¹ Ω / □ can be formed by the thermal spraying method. Prior to the formation of the first ceramic layer 130A, for example, nickel (Ni-5% by weight Al) containing about 5% by weight of aluminum is sprayed as a thermal spray underlayer, and the first thermal spraying layer is formed on the thermal spray underlayer. Ceramic layer 130
A may be formed by a thermal spraying method. After that, the electrode 19 is formed on the first ceramic layer 130A using a brazing material. The planar shape of the electrode 19 is schematically shown in FIG. 11C, and the electrode 19 has a so-called comb-shaped electrode shape and is of a bipolar type. In FIG. 11C, the electrodes 19 are hatched to clarify the electrodes 19. In addition, examples of the brazing material include, but are not limited to, an Al-Mg-Ge alloy, an alloy made of titanium, tin, antimony, or magnesium. The linear expansion coefficient [unit: 10 ⁻⁶ / K] of the brazing material constituting the electrode 19 is also given assuming that the linear expansion coefficient of the base material is α ₁ [unit: 10 ⁻⁶ / K].
It is desirable that the thickness be in the range of (α ₁ -4) or more and (α ₁ +4) or less, but if the thickness of the electrode 19 is small, the linear expansion coefficient of the brazing material is out of this range. The problem is unlikely to occur. Thereafter, TiO ₂ is added to Al ₂ O ₃ for about 2.5
The second ceramic layer 130B is formed by a thermal spraying method by spraying a mixed powder having a particle diameter of about 10 μm mixed in a weight percentage in a molten state by a vacuum spraying method and solidifying the mixed powder. Thus, the ceramic layer 13C (the first ceramic layer 130A and the second ceramic layer 130B) in which the electrode 19 is formed can be formed.

The substrate mounting stage 10C having such a configuration
A DC voltage is applied from a DC power supply 35 to the electrode 19 of the ceramic layer 1 through a wiring (not shown), so that the ceramic layer 1
3C functions as an electrostatic chuck. In FIGS. 11A, 12 and 13, the ceramic layer 13C is represented by a single layer. As shown in a schematic sectional view of FIG. 12B, a ceramic layer 13C may be formed on the side surface of the base material 12. Furthermore, the electrode 19 can be applied to the base mounting stage described in Embodiments 4 to 6. For example, FIG. 7A is a schematic cross-sectional view of a substrate mounting stage 10C in which an electrode 19 is provided on the substrate mounting stage described with reference to FIGS. 7B and 8B. These are shown in FIGS. 12A, 12B and 12C. Further, a substrate mounting stage 10D in which electrodes 19 are provided on a substrate mounting stage having substantially the same structure as the substrate mounting stage described with reference to FIGS. 9A, 9B, and 9C.
13 (A), (B) and (C) in FIG.
Shown in The planar shape of the electrode 19 is not limited to a so-called comb-shaped electrode shape, and may be, for example, two semicircular shapes obtained by dividing a circle into two.
Any pair of shapes can be used.

The plasma etching device is not limited to the structure shown in FIG. FIG. 14 is a conceptual diagram of an ICP type plasma etching apparatus (hereinafter simply referred to as an etching apparatus 20A). The reference numerals in FIG. 14 are partially the same as those in FIG. The etching apparatus 20A includes a chamber 71 including a chamber side wall 72 and a top plate 73, a heater 74 for heating the top plate 73, and a chamber side wall 7
2 is provided with an inductive coupling coil 75 disposed outside. An RF power supply 77 is connected to the inductive coupling coil 75. The chamber side wall 72 is made of quartz, and the top plate 73 is made of a composite member as described later.
A substrate mounting stage 10 (FIG. 1A) for holding and fixing the silicon semiconductor substrate 50 is provided in the chamber 71.
See also). Further, an exhaust port 76 for exhausting gas in the chamber 71 is connected to negative pressure means (not shown) such as a vacuum pump. A bias power source 34 for controlling the ion energy incident on the silicon semiconductor substrate 50 is connected to the base mounting stage 10 via a matching network 33.
The ceramic layer 1 is attached to the temperature control jacket corresponding to
3 is connected to a DC power supply 35 for exerting an electrostatic attraction force. Further, the heater 14 provided on the base material 12 of the base mounting stage 10 is connected to a power supply 36.
The substrate mounting stage may have the structure shown in FIG. In FIG. 14, details of the etching apparatus such as an etching gas introduction unit and a gate valve are not shown.

FIG. 15 is a conceptual diagram of a parallel plate type plasma etching apparatus (hereinafter, simply referred to as an etching apparatus 20B) provided with an upper counter electrode 80 constituted by a composite member. FIG. 16A is a schematic cross-sectional view of the upper counter electrode 80.

In this etching apparatus 20B, a parallel plate upper counter electrode 80 is arranged above the chamber 84 so as to face the substrate mounting stage 10 corresponding to the lower electrode. The upper counter electrode 80 is connected to an RF power source 82 via a matching network 81. Here, reference numeral 85 denotes a chamber side wall, reference numeral 86 denotes a top plate, and reference numeral 87 denotes an exhaust port for exhausting gas in the chamber 84. In addition, the etching apparatus 2
In FIG. 0B, components and parts denoted by the same reference numerals as those of the etching apparatus 20 shown in FIG. 2 are the same as those of the etching apparatus 20 shown in FIG.

In the composite member forming the upper opposing electrode 80, as in the third embodiment, the composition of the ceramic member forming the base material 112 was cordierite ceramics. The composition of the aluminum-based material constituting the base material is aluminum (Al) and silicon (Si),
The aluminum-based material contains 20% by volume of silicon based on the aluminum-based material. The base material 112
It has a value closer to metal than the electrical and thermal conductivity of pure ceramics. Therefore, such a base material 112
A high frequency can be applied to the upper opposing electrode 80 manufactured from the same without any problem. The material forming the ceramics layer 113 is Al ₂ to which about 2.5% by weight of TiO ₂ is added.
O ₃ . Ceramic layer 113 having a thickness of about 0.2 mm
Are formed on the surface of the base material 112 by thermal spraying. The coefficient of linear expansion of the ceramic layer 113 having such a composition is 1
About 9 × 10 ^-6 / K at an average value at 00 to 300 ° C.
It is. Therefore, α ″ ₂ is about 9, and the coefficient of linear expansion α ″ ₂ of the ceramic layer 113 is (α ″ ₁ −4) ≦ α ″ ₂ ≦
(Α ″ ₁ +4). The coefficient of linear expansion of Al ₂ O ₃ itself is about 8 × 10 ⁻⁶ / K, where α ″ ₁ is the coefficient of linear expansion of the base material 112. is there.

Inside the upper counter electrode 80, a heater 114 composed of a known sheathed heater is provided. The heater 114 includes a heater body (not shown) and a sheath tube (not shown) provided outside the heater body and protecting the heater body. And the heater 114 is
It is connected to a power supply 83 (see FIG. 15) via wiring (not shown). The thermal expansion of the heater 114 depends on the upper counter electrode 8.
Affects 0. Therefore, it is preferable to use a material having a value close to the coefficient of linear expansion of the ceramic layer 113 and the base material 112. Specifically, titanium or stainless steel or the like, it is preferable that the linear expansion coefficient which sheath tube made from the material of the ^{9 × 10 -6 / K~12 × 10} -6 / K. That is,
The linear expansion coefficient α ″ _H [unit: 10 ⁻⁶ / K] of the material constituting the heater 114 (the material of the sheath tube in contact with the base material 112) is
It is preferable to satisfy (α ″ ₁ −4) ≦ α ″ _H ≦ (α ″ ₁ +4) Since the linear expansion coefficient of the main body of the heater 114 does not affect the upper counter electrode 80, There is no particular limitation.

The method of manufacturing the upper counter electrode 80 composed of a composite member can be substantially the same as the method of manufacturing the composite member described in the third embodiment. Description is omitted. Further, the upper opposing electrode 80 can be manufactured by the same method as the method of manufacturing the composite member described in the fourth to sixth embodiments.
Further, as shown in FIG. 16B, the ceramic layer 116 is brazed by a brazing material 117 based on a brazing method.
2 may be attached to the surface.

Further, as shown in FIG. 17, a disk-shaped member 118 made of stainless steel or aluminum is used.
The upper facing electrode 80A may be formed by fixing the composite member 111 to the upper surface by brazing or screwing.
The heater 114A is provided inside the disk-shaped member 118. The composite member 111 is fixed to the upper and lower surfaces of the disk-shaped member 118 (see FIG. 17A). The structure of the composite member 111 has the same structure as the composite member 11 described in the third to sixth embodiments. In the structure shown in FIG. 17B, the ceramic layer 116 is attached to the surface of the base material 112 by the brazing material 117. Also, in FIG. 17C, the disc-shaped member 1
The composite member is omitted from the upper surface of 18.

The chamber side wall or the top plate of the plasma etching apparatus is preferably made of a composite member. Plasma etching apparatus 20B shown in FIG.
A schematic partial cross-sectional view of the chamber side wall 85 in FIG.
It is shown in FIGS. The chamber side wall 85 is made of a composite member 211 including a base material 212 in which the structure of the ceramic member is filled with an aluminum-based material, and a ceramic layer 213 provided on the surface of the base material 212.

A known seal is provided inside the chamber side wall 85.
A heater 214 composed of a heater is provided (see FIG.
18 (A) and (B)). The heater 214 is
Heater body (not shown) and the heater body
And a sheath tube (not shown) that protects the heater body.
Have been. The heater 214 is connected to a power source via a wiring.
(Not shown). Thermal expansion of heater 214
Affects the chamber side wall 85. Therefore, the base material
212 and the coefficient of linear expansion α ′ of the ceramic layer 213 ₁, Α '_Two
It is preferable to use a material having a value close to. concrete
Has a coefficient of linear expansion of 9 ×, such as titanium or stainless steel.
10^-6/ K ~ 12 × 10^-6/ K made of material
Preferably, a tube is used. That is, the heater 214 is configured.
Coefficient of expansion of material (material of sheath tube in contact with base material 212)
α ’_H[Unit: 10^-6/ K] is (α '₁-4) ≦ α ′_H
≤ (α '₁+4) is preferably satisfied. Hi
The coefficient of linear expansion of the main body of the
There is no particular limitation as it has no effect. If
In some cases, the heater 214 is provided and
The piping having the same structure as the piping 15 described above is connected to the chamber side wall 8.
5 or a heater 214 may be provided.
Instead, a pipe is placed inside the chamber side wall 85
Is also good.

Alternatively, as shown in a schematic sectional view of FIG. 18B, the ceramic layer 216 may be provided on the surface of the base material 212 by a brazing method instead of a thermal spraying method. In this case, a ceramic layer 216 made of a ceramic annular member made of Al ₂ O ₃ produced by a sintering method is used.
For example, it may be attached to the surface (inner surface) of the base material 212 by a brazing method using an Al-Mg-Ge brazing material 217 at a temperature of about 600 ° C. In addition, examples of the brazing material include alloys composed of titanium, tin, antimony, and magnesium.

Alternatively, as shown in the schematic cross-sectional views of FIGS. 19A and 19B, instead of embedding the heater in the base material 212, the outer surface of the chamber side wall 85 (the surface facing the chamber 84) is used. A heater 214A made of, for example, a PBN heater may be attached to the surface on the opposite side.

FIGS. 20 to 22 show schematic side walls of a plasma etching apparatus manufactured by fixing a composite member 211 to a hollow cylindrical member 218 made of stainless steel or aluminum by brazing or screwing. FIG. 20 (A) or (B), a heater 214B (may be a pipe) is disposed inside the hollow cylindrical member 218. The base material 212 is fixed to the inner surface and the outer surface of the hollow cylindrical member 218. The structure of the composite member 211 fixed to the inner surface (the chamber 84 side) of the hollow cylindrical member 218 has the same structure as the composite member described in the embodiment. (A) or (B) of FIG.
In the figure, the base material 212 on the outer surface of the hollow cylindrical member 218 is omitted. 22 (A) or (B), the PBN heater 214 is provided on the outer surface of the hollow cylindrical member 218.
C is attached. The composite member 211 is fixed to the inner surface of the hollow cylindrical member 218.

Top plates 24 and 7 of plasma etching apparatus
3, 86 may have the same structure. In addition, the chamber side wall or top plate of these plasma etching devices is:
Since the composite member can be manufactured based on the same method as the manufacturing method of the composite member described in Embodiment Modes 3 to 6, detailed description will be omitted.

[0154]

As is apparent from the above description, the substrate mounting stage used in the plasma etching method of the present invention can be rapidly moved up and down by setting the linear expansion coefficient of the constituent material within a predetermined range. No damage to temperature. Therefore, it is possible to continuously perform etching processes having greatly different temperatures in a single plasma chamber, and it is possible to greatly improve throughput and economic efficiency. In particular, the anisotropic etching of the polymetal film can be easily and accurately performed by the plasma etching method of the present invention, so that the practical value of the polymetal film can be significantly increased.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a substrate mounting stage constituted by a composite member.

FIG. 2 is a conceptual diagram of a helicon wave plasma etching apparatus used in the first embodiment of the present invention.

FIG. 3 is a schematic partial cross-sectional view of a semiconductor substrate and the like for describing a plasma etching method according to the first embodiment of the present invention.

FIG. 4 is a schematic partial cross-sectional view of a semiconductor substrate and the like for explaining the plasma etching method of the first embodiment of the invention, following FIG. 3;

FIG. 5 is a schematic partial cross-sectional view of a semiconductor substrate and the like for describing a plasma etching method according to a second embodiment of the present invention.

FIG. 6 is a schematic partial cross-sectional view of the semiconductor substrate and the like for explaining the plasma etching method of the first embodiment of the invention, following FIG. 5;

FIG. 7 is a schematic cross-sectional view showing a modified example of the composite member constituting the base mounting stage.

FIG. 8 is a schematic cross-sectional view showing a modified example of the composite member forming the base mounting stage.

FIG. 9 is a schematic cross-sectional view showing a modified example of a composite member constituting the base mounting stage.

FIG. 10 is a schematic cross-sectional view showing a modified example of the composite member forming the base mounting stage.

FIG. 11 is a schematic cross-sectional view showing a modified example of the base mounting stage constituted by a composite member.

FIG. 12 is a schematic cross-sectional view showing a modified example of the composite member constituting the base mounting stage shown in FIG.

FIG. 13 is a schematic cross-sectional view showing a modified example of the composite member constituting the base mounting stage shown in FIG.

FIG. 14 is a conceptual diagram of an ICP type plasma etching apparatus.

FIG. 15 is a conceptual diagram of a parallel plate type plasma etching apparatus provided with an upper counter electrode.

FIG. 16 is a schematic cross-sectional view showing a composite member constituting an upper counter electrode.

FIG. 17 is a schematic cross-sectional view showing a modification of the composite member forming the upper counter electrode.

FIG. 18 is a schematic partial sectional view showing a composite member constituting a side wall of the plasma etching apparatus.

FIG. 19 is a schematic partial cross-sectional view showing a modified example of the composite member forming the side wall of the plasma etching apparatus.

FIG. 20 is a schematic partial cross-sectional view showing a modification of the composite member forming the side wall of the plasma etching apparatus.

FIG. 21 is a schematic partial cross-sectional view showing a modification of the composite member forming the side wall of the plasma etching apparatus.

FIG. 22 is a schematic partial cross-sectional view showing a modified example of the composite member forming the side wall of the plasma etching apparatus.

[Explanation of symbols]

10, 10A, 10B, 10C: substrate mounting stage, 11, 111, 211 ... composite member, 12, 11
2,212: Base material, 13, 13C, 113, 213
... Ceramic layers, 14, 14A, 14B, 114
... heater, 15 ... piping, 16, 116, 216
... ceramic layers, 17, 117, 217 ... brazing material, 18, 118, 218 ... disk-shaped members, 19
..Electrodes, 20, 20A, 20B ... plasma etching apparatus, 21 ... plasma container, 22 ... double loop antenna, 23 ... solenoid coil assembly, 25 ... single loop antenna, 27 ・
..First RF power supply, 29 ... Second RF power supply, 30 ...
Processing chamber, 31: multi-pole magnet, 34: bias power supply, 35: DC power supply (for electrostatic chuck),
36 ... power supply (for heater), 37 ... fluorescent fiber thermometer, 38 ... control device, 39A, 39B ... piping, 39C ... bypass piping, 40 ... heat medium supply device 50: silicon semiconductor substrate, 53: gate oxide film, 54: polysilicon layer, 55: titanium nitride layer, 56: tungsten layer, 57A, 57B
... polymetal film, 58 ... silicon nitride layer, 59
... Organic resist layer, 60 ... Composite mask, 61
A, 61B: gate electrode, 62: tungsten nitride layer, 71: chamber, 75: inductive coupling coil, 77, 82: RF power supply, 80: upper counter electrode, 82 ..RF power supply, 84 ... chamber

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01L 27/092 H01L 29/78 301F 29/78 F term (reference) 4M104 BB01 BB18 BB30 BB33 DD17 DD37 DD43 DD65 EE03 FF13 FF18 GG14 HH14 5F004 AA02 BA04 BA14 BA20 BB11 BB25 BB26 BB29 CA04 DA00 DA01 DA04 DA11 DA16 DA18 DA26 DA28 DB02 DB08 DB10 DB12 EA03 EA28 EB02 5F033 HH04 HH19 HH33 HH34 MM08 QQ08 QQ10 QQ12 QQ15 QQ16 QQ21 QQ28 QQ29 RR04 RR06 SS08 WW03 XX03 XX33 XX34 5F040 DA00 DB03 EC02 EC04 EC07 EC12 ED03 EK01 EK05 FC11 FC21 5F048 AA07 AC03 BA01 BA16 BB06 BB07 BB09 BB13 BE03 BG12

Claims (21)

[Claims] 1. A composite member comprising a base material in which the structure of a ceramic member is filled with an aluminum-based material and a ceramic layer provided on the surface of the base material, having a function of electrostatic chucking. A plasma etching method of using a substrate mounting stage provided with a temperature control means, mounting the substrate on the substrate mounting stage, and etching a layer to be processed on the substrate, wherein the layer to be processed is silicon The base material layer and a metal layer having different etching characteristics from the silicon-based material layer are laminated in this order, and (a) etching the metal layer while controlling the temperature of the base mounting stage to the first temperature. And (b) etching the silicon-based material layer while controlling the temperature of the substrate mounting stage to a second temperature different from the first temperature. Grayed method. 2. The plasma etching method according to claim 1, wherein the metal layer is made of a high melting point metal material. 3. The plasma etching method according to claim 2, wherein the high melting point metal material is tungsten. 4. The plasma etching method according to claim 3, wherein the first temperature is lower than the second temperature. 5. The method according to claim 1, wherein in the step (a), the metal layer is etched using a fluorine-based etching gas, and in the step (b), the silicon-based material layer is etched using a chlorine-based etching gas. Item 4
3. The plasma etching method according to 1. 6. The layer to be processed further includes a barrier layer between the silicon-based material layer and the metal layer.
6. The plasma etching method according to claim 5, wherein the barrier layer is also etched. 7. The plasma etching method according to claim 3, wherein the first temperature is higher than the second temperature. 8. The method according to claim 1, wherein in the step (a), the metal layer is etched using a chlorine-based etching gas, and in the step (b), the silicon-based material layer is etched using a chlorine-based etching gas. Item 7
3. The plasma etching method according to 1. 9. The process layer further comprises a barrier layer between the silicon-based material layer and the metal layer, wherein the step (a) or the step (b)
9. The plasma etching method according to claim 8, wherein the barrier layer is also etched. 10. The plasma etching method according to claim 8, wherein prior to step (a), an etching mask including at least an inorganic compound layer is formed on the layer to be processed. 11. The plasma etching method according to claim 1, wherein a gate electrode of the MIS transistor is formed by etching the layer to be processed. 12. The plasma etching method according to claim 1, wherein said temperature control means comprises a heater. 13. A heater is disposed inside a base material. When a linear expansion coefficient of the base material is α ₁ [unit: 10 ⁻⁶ / K], a linear expansion coefficient α of a material forming the heater is defined as α. _H [Unit: 10
^-6 / K], wherein (α ₁ -4) ≦ α _H ≦ (α ₁ +4) is satisfied. 14. The temperature control means comprises a pipe arranged inside the base material for flowing a heat medium for temperature control, wherein the coefficient of linear expansion of the base material is α ₁ [unit: 10 ⁻⁶ / K]. ], The linear expansion coefficient α _P [unit: 10 ⁻⁶ / K] is (α ₁ −
4. The plasma etching method according to claim 1, wherein 4) ≦ α _P ≦ (α ₁ +4) is satisfied. 15. The coefficient of linear expansion of the base material is α ₁ [unit: 10 ⁻⁶ /
K], the coefficient of linear expansion α ₂ [unit: 10 ⁻⁶ / K] of the ceramic layer satisfies (α ₁ -4) ≦ α ₂ ≦ (α ₁ +4). 3. The plasma etching method according to 1. 16. The composition of the ceramic member forming the base material is cordierite ceramics, the composition of the aluminum-based material forming the base material is aluminum and silicon, and the material forming the ceramic layer is aluminum oxide. The plasma etching method according to claim 15, wherein: 17. The composition of a ceramic member forming a base material is aluminum nitride, the composition of an aluminum-based material forming a base material is aluminum or aluminum and silicon, and the material forming a ceramic layer is aluminum oxide or nitride. The plasma etching method according to claim 15, wherein the plasma etching method is aluminum. 18. The composition of the ceramic member constituting the base material is silicon carbide, the composition of the aluminum-based material constituting the base material is aluminum or aluminum and silicon, and the material constituting the ceramic layer is aluminum oxide or nitride. 2. The method according to claim 1, wherein the material is aluminum.
6. The plasma etching method according to 5. 19. The composition of the ceramic member forming the base material is aluminum oxide, the composition of the aluminum-based material forming the base material is aluminum or aluminum and silicon, and the material forming the ceramic layer is aluminum oxide. The plasma etching method according to claim 15, wherein: 20. The plasma etching method according to claim 1, wherein the ceramics layer is formed on a surface of the base material by a thermal spraying method. 21. The method according to claim 1, wherein the ceramic layer is attached to the surface of the base material by a brazing method.
3. The plasma etching method according to 1.