JP2003197725A - Vacuum chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum chuck for holding a wafer in which the thermal expansion of the chuck is controlled even when a temperature rises at the time of processing and the temperature of a wafer on the chuck can be kept at a constant level, and a vacuum chuck in which high-accuracy machining can be performed on the wafer by enhancing rigidity while controlling an increase in the weight of the chuck and the scale-down of a circuit can be dealt with sufficiently. <P>SOLUTION: The vacuum chuck for holding a wafer constituting a semiconductor manufacturing unit is composed of low thermal expansion ceramic having a coefficient of thermal expansion not higher than 1.5×10<SP>-6</SP>/°C and porosity not higher than 0.5% wherein vacuum suction passages and cavities are arranged internally. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for holding a semiconductor wafer used in a semiconductor manufacturing apparatus, more specifically, for example, a vacuum chuck for an exposure apparatus or a vacuum chuck for polishing a wafer, and preferably a code chuck. It consists of low thermal expansion ceramics containing at least one of erite and eucryptite as a main component, and removes the heat generated in the wafer during semiconductor manufacturing, and the passage of the cooling medium in order to make the temperature inside the wafer uniform. The present invention relates to a member having a possible structure and a member capable of achieving weight reduction while maintaining rigidity as a structure.

[0002]

2. Description of the Related Art With the high integration of LSIs and the like, miniaturization of circuits is progressing, and the line width of semiconductors is about to reach a level below 0.1 μm. Therefore, in a semiconductor manufacturing process, for example, a pattern transferred and formed on a wafer through a mask by an exposure apparatus is miniaturized, and accordingly, a member used for the exposure apparatus is also highly accurate and has a low thermal expansion property. Is required.

In JP-A-11-209171 and JP-A-11-343168, as a material used for a vacuum chuck for holding a wafer, a coefficient of thermal expansion at a temperature of 10 ° C. to 40 ° C. is 1 × 10 ⁻⁶ / Dense and low thermal expansion ceramics that are below ℃ have been introduced. By using such a low thermal expansion ceramics, the thermal expansion of the chuck during processing can be eliminated as much as possible, and the accuracy is higher than that of the conventional metal, alumina, or SiC chuck having a large thermal expansion coefficient. It is possible to keep it high.

[0004]

When the low thermal expansion ceramics is used as the material of the chuck, the thermal expansion can be suppressed even if the chuck itself has a temperature difference, and the flatness of the wafer can be maintained with high accuracy. Is possible. However, depending on the processing environment, for example, when the temperature of the Si wafer rises due to exposure, the Si material has a thermal expansion coefficient of about 3.5 × 10 ⁻⁶ / ° C. and is not a low thermal expansion material. Due to the temperature difference and the in-plane temperature difference, the positional shift within the wafer surface is likely to occur, and the deterioration of accuracy due to thermal expansion such as the deterioration of exposure accuracy cannot be avoided. Therefore, it is necessary not only to secure the flatness of the jig by using a low thermal expansion material as the material of the wafer holding jig but also to prevent the temperature rise of the wafer and the in-plane temperature difference from occurring. Japanese Patent Laid-Open No. 2-67714 discloses a conventional technique in which a temperature adjusting cooling medium is flown through a chuck for holding a wafer to keep the temperature of the wafer on the chuck constant in order to suppress a temperature rise due to exposure of the wafer. Chuck has been introduced. However, the material of the chuck suitable for use has not been disclosed, and when a chuck is made of a conventional material such as metal, alumina, or SiC and exposed, the thermal expansion difference due to the temperature variation of the entire chuck. Therefore, the chuck itself may be deformed, and it may be difficult to secure the flatness and accuracy of the wafer.

The present invention is a wafer-holding vacuum chuck used in a semiconductor manufacturing apparatus, which suppresses thermal expansion of the chuck even when the temperature rises during processing and keeps the temperature of the wafer on the chuck constant. It is an object of the present invention to provide a vacuum chuck that enables high-precision processing on a wafer by increasing rigidity while suppressing an increase in weight of the chuck and that can sufficiently cope with miniaturization of a circuit.

[0006]

The vacuum chuck of the present invention is a wafer-holding vacuum chuck constituting a semiconductor manufacturing apparatus, and has a thermal expansion coefficient of 1.5 × 10 ^{−6 at} a temperature of 10 ° C. to 40 ° C. It is characterized in that it is made of low thermal expansion ceramics having a porosity of 0.5% or less and a temperature of / ° C or less, and a vacuum suction path and a cavity are provided therein.

The Young's modulus of the low thermal expansion ceramics is 120
GPa or more is preferable, and volume resistivity is preferably 10 ⁸ Ω · cm or less.

In the vacuum chuck of the present invention, a plurality of ceramic base materials including a groove-processed ceramic base material are laminated, and the base materials are bonded to each other via a metal-based bonding material layer or an inorganic-based bonding material layer. It is preferable that the base material is bonded and a cavity is provided in at least one of the bonding surfaces of the base materials.

The low thermal expansion ceramic is made of at least one of cordierite and eucryptite.
vol% to 100 vol%, at least one selected from the group consisting of carbides, nitrides, borides and silicides of 4a group elements, 5a group elements and 6a group elements and boron carbide, silicon carbide, silicon nitride, aluminum nitride Is preferably a ceramic containing 0 vol% to 40 vol%.

The low thermal expansion ceramics include 57 vol% to 99.89 vol% of at least one of cordierite and eucryptite and 0.
01 vol% to 3 vol%, at least one selected from the group consisting of carbides, nitrides, borides and silicides of 4a group elements, 5a group elements and 6a group elements and boron carbide, silicon carbide, silicon nitride, aluminum nitride Is preferably 0.1 vol% to 40 vol%.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION (Vacuum chuck) The vacuum chuck of the present invention is a wafer-holding vacuum chuck that constitutes a semiconductor manufacturing apparatus, and has a thermal expansion coefficient of 1.5 × 10 5 at a temperature of 10 ° C. to 40 ° C. ^-6 / ° C or less, and a porosity of 0.
It is made of low thermal expansion ceramics of 5% or less, and is characterized in that a vacuum suction path and a cavity are provided inside.

The structure of the vacuum chuck of the present invention is shown in FIG. 1A is a plan view, and FIG. 1B is A in FIG.
-A sectional drawing and FIG.1 (c) are figures which show the joining surface of a vacuum chuck. A vacuum suction path 12 is provided inside the vacuum chuck.
And a cavity 13 is provided. A cooling medium can flow in the cavity 13. The wafer is held on the convex portion 11 and mounted on an exposure device or the like (not shown). In the example shown in FIG. 1 (c), the cavity 13 has a substantially concentric shape, but the cavity of the vacuum chuck of the present invention is not limited to this shape.

The structure of another vacuum chuck of the present invention is shown in FIG. 2A is a plan view, FIG. 2B is a sectional view taken along the line AA of FIG. 2A, and FIG. 2C is a view showing a bonding surface of the vacuum chuck. Inside the vacuum chuck, the vacuum suction path 2
2 and a cavity 23 are provided. In the example of FIG. 2, the cooling medium does not flow into the cavity 23, but the cavity 23 is designed to be larger than the vacuum chuck of FIG. Figure 2 (c)
In the example shown in, the cavity 23 has a concentric shape.

The structure of still another vacuum chuck of the present invention is shown in FIG. 3A is a plan view and FIG. 3B is FIG.
FIG. 3A is a cross-sectional view taken along the line AA of FIG. 3A, and FIG. 3C is a view showing a bonding surface of the vacuum chuck. A vacuum suction path 32 and a cavity 33 are arranged inside the vacuum chuck. The example of FIG. 3 is similar to the example of FIG.
/ 4 yen (fan shape). The shape of the hollow portion is not limited to the concentric circle shape, the 1/4 circle shape (fan shape), and the like described above.

The vacuum suction path is an intake path for vacuum suction. By vacuum suction, the wafer can be held securely on the chuck. In FIGS. 1, 2 and 3,
An example in which the wafer is suction-held at the central portion of the chuck is illustrated, but the present invention is not limited to this mode.

As in the example shown in FIG. 1, a cooling medium such as a liquid such as water or a gas can be circulated in the cavity. By arranging a cavity that circulates the cooling medium, it is possible to efficiently remove the heat generated on the wafer during exposure and polishing, ensure uniform heat distribution within the chuck, and maintain the chuck flatness with high accuracy. It becomes possible to cope with the miniaturization of the circuit. If the cavity is too small, the circulating cooling fluid is too small to provide sufficient cooling capacity. On the other hand, if the cavity is too large, the rigidity becomes insufficient and the chuck is easily deformed, and, for example, the exposure accuracy decreases. The size of the cavity is preferably determined in consideration of these. FIG. 1 illustrates a mode in which the cooling medium enters from the central part of the chuck and exits from the peripheral part of the chuck.
The present invention is not limited to this aspect.

Even with the structure in which the cooling medium does not flow, as in the example shown in FIGS. 2 and 3, by providing the cavity, it is possible to reduce the weight of the chuck and improve its rigidity.

That is, it is effective to increase the height (thickness) of the structure in order to improve the rigidity of the chuck with the same material, but if the height is increased as it is, the weight increases. For example, in the case of a wafer-holding vacuum chuck used in an exposure apparatus, the chuck is placed on a base that can move in the XY directions and the wafer on the chuck is exposed while moving in the XY directions. When the weight increases, there arises a problem that the load on the drive system increases during movement. Therefore, by providing the hollow structure (rib structure), the rigidity of the structure can be increased while suppressing an increase in weight.

The low thermal expansion ceramics which is the base material of the vacuum chuck of the present invention contains at least one of cordierite and eucryptite in an amount of 60 vol% to 100 v.
0% by volume of at least one selected from the group consisting of carbides, nitrides, borides and silicides of 4a group elements, 5a group elements and 6a group elements and boron carbide, silicon carbide, silicon nitride and aluminum nitride. ~ 40
It is preferable to contain vol%. By densely sintering the base material, the coefficient of thermal expansion is 1.5 × 10 ⁻⁶ /
It is possible to obtain a low thermal expansion ceramic having a temperature of ℃ or less.

That is, the low thermal expansion ceramics are
It is preferable to contain 60% by volume to 100% by volume of cordierite, eucryptite, or a combination thereof. Since both cordierite and eucryptite are low thermal expansion materials, the coefficient of thermal expansion can be reduced. In addition, cordierite and eucryptite can be used as they are as a base material. On the other hand, aluminum titanate has a low thermal expansion property, but it is difficult to densify it, and even if it can be densified, it has low rigidity and is difficult to use. Spodumene can be dense, but has a Young's modulus of 70 GPa.
It is difficult to use because it is low. Cordierite and eucryptite have an average particle size of 10 μm or less, for example, 2
It is preferable to use a powder having a size of μm to 3 μm.

This low thermal expansion ceramic is selected from the group consisting of carbides, nitrides, borides and silicides of 4a group elements, 5a group elements and 6a group elements and boron carbide, silicon carbide, silicon nitride and aluminum nitride. It is preferable to contain at least one kind. Carbides, nitrides of 4a group elements, 5a group elements and 6a group elements,
Borides and suicides and materials selected from the group consisting of boron carbide, silicon carbide, silicon nitride, and aluminum nitride have high hardness and high rigidity, and can impart wear resistance and high rigidity to the sintered body. Because you can. Further, most of these have conductivity, and can impart conductivity to the sintered body and release the generated static electricity. Furthermore, most of these can make the sintered body black or gray by adding them, and can impart visibility and antifouling property.

Examples of the Group 4a element constituting the carbide, nitride, boride and silicide are titanium (T
i), zirconium (Zr), hafnium (Hf) and the like, the 5a group element includes, for example, vanadium (V), niobium (Nb), tantalum (Ta), and the 6a group element includes, for example, There are chromium (Cr), molybdenum (Mo), tungsten (W), and the like. Preferred specific examples include tungsten carbide (tungsten carbide), titanium carbide, tantalum carbide, zirconium nitride, tantalum nitride, titanium boride, zirconium boride, tantalum silicide, and molybdenum silicide. Of these, tungsten carbide is particularly preferable because it has low hardness, high rigidity, low thermal expansion, conductivity, and black coloration.

Boron carbide, silicon carbide, silicon nitride, aluminum nitride and tungsten carbide are more preferable because they have low thermal expansion properties. Since the coefficient of thermal expansion of the sintered body is related to the coefficient of thermal expansion and volume ratio of each material to be mixed, the use of the low thermal expansion base material enables the use of a larger amount than other materials. . Therefore, it is possible to improve both the Young's modulus and wear resistance of the sintered body. The average particle size of such additives is 1 μm
The following are preferred.

Further, the addition of a high thermal conductive material such as silicon carbide or aluminum nitride is preferable for improving the thermal conductivity of the sintered body. This is because the thermal conductivity of the sintered body is related to the thermal conductivity and volume ratio of each material to be mixed.
By using a material having a high thermal conductivity, the heat generated in the wafer at the time of exposure or polishing is quickly conducted, and the thermal uniformity in the chuck can be improved.

The content of carbides, nitrides, borides and silicides of 4a group elements, 5a group elements and 6a group elements as well as boron carbide, silicon carbide, silicon nitride and aluminum nitride is preferably 40 vol% or less. 40 added
If it exceeds vol%, the low thermal expansion property is likely to be impaired.

This low thermal expansion ceramic contains 60 vol% to 98 vol% of at least one of cordierite and eucryptite, 4a group element, 5
It is more preferable to contain 2 to 40 vol% of at least one selected from the group consisting of carbides, nitrides, borides and silicides of group a elements and group 6a elements, and boron carbide. By adding 2 vol% or more, the rigidity and wear resistance of the sintered body can be markedly improved.

Another low thermal expansion ceramic which is the base material of the vacuum chuck of the present invention comprises 57 vol% to 9 of at least one of cordierite and eucryptite.
9.89vol%, 0.01vol% to 3v of carbon
%, at least one selected from the group consisting of carbides, nitrides, borides and silicides of 4a group elements, 5a group elements and 6a group elements and silicon carbide, boron carbide, silicon nitride and aluminum nitride. 1 vol
% To 40 vol% is preferable. When such a condition is satisfied, it is possible to obtain a ceramic that has low thermal expansion properties, high resistance in addition to low resistance and abrasion resistance, and black color. The black low thermal expansion ceramics can be applied to various applications in which low thermal expansion, low resistance, abrasion resistance and rigidity are required, and in particular, semiconductor manufacturing equipment such as vacuum chucks for exposure equipment and stage members. Suitable for parts or parts for LCD manufacturing equipment.

The reason why carbon is added to the low thermal expansion ceramics is that it is possible to easily reduce the resistance of the sintered body by adding carbon. On the other hand, if the addition amount exceeds 3 vol%, it becomes difficult to obtain the denseness of the sintered body. Carbon is preferably used in the form of powder having an average particle size of 0.1 μm or less. Carbon may be added as it is as carbon powder, but a resin that allows carbon to remain after firing, such as phenol resin or furan resin, may be added before molding. By so doing, the resin can be dissolved in alcohol, water, etc. during mixing, so that carbon can be uniformly dispersed in the molded body.

The volume percentage (vol%) indicating the content of the component in the substrate is, for example, secondary ion mass spectrometry (SIMS), atomic absorption method, ICP emission spectrometry, etc. After determining that weight%
Can be obtained by dividing by the general specific gravity of the component.

The coefficient of thermal expansion of the low thermal expansion ceramics is 1
It is not more than 1.5 × 10 ⁻⁶ / ° C. at a temperature of 0 ° C. to 40 ° C. If the coefficient of thermal expansion is greater than 1.5 × 10 ^-6 / ° C,
It is not possible to sufficiently cope with the manufacture of fine circuits that require high precision. The coefficient of thermal expansion is -0.5 to 1.5 x 10
^-6 / ° C is preferable, and -0.5 to 1.0x10 ^-6 / ° C is more preferable.

The porosity of the low thermal expansion ceramics is 0.5.
% Or less, preferably 0.2% or less, and more preferably 0.1% or less. If the porosity is greater than 0.5%, it becomes difficult to obtain the rigidity and strength required for ceramics. Also,
Particles adhere to the pores and the height of the wafer shifts when the wafer is held, which easily causes exposure defects due to focus shift in the exposure apparatus. Therefore, the pore size should also be small, and the pore size of ceramics should be
Assuming that it is used as a base material for a wafer holding vacuum chuck used in an exposure apparatus, 5 μm or less is preferable, and 2 μm is preferable.
The following is more preferable.

The Young's modulus of the low thermal expansion ceramics is 12
0 GPa or more is preferable, and 130 GPa or more is more preferable. The wafer holding vacuum chuck used in the exposure apparatus is placed on a stage that can be stepped in the XY directions, and is exposed in the XY directions while being moved. Therefore, if the rigidity is low, vibration during movement is not attenuated, and exposure failure is likely to occur. Further, the vacuum chuck of the present invention has a structure capable of circulating a cooling medium inside, but when the rigidity of the vacuum chuck is low, it is not possible to suppress the vibration generated in the chuck during the circulation of the cooling medium,
Therefore, exposure failure is likely to occur.

The volume resistivity of the low thermal expansion ceramics is 10
^It is preferably ⁸ Ω · cm or less, more preferably 10 ⁷ Ω · cm or less. When the volume resistivity is higher than 10 ⁸ Ω · cm, static electricity generated during wafer processing becomes difficult to escape, and particles are likely to adhere to the surface of the vacuum chuck.
As a result, the height of the wafer shifts when holding the wafer, and, for example, in the case of an exposure apparatus, exposure failure due to focus shift easily occurs. A volume resistance value of 10 ⁸ Ω · cm is a limit value for removing static electricity generated on the product surface, and a volume resistivity of 10 ⁸ Ω · cm or less means that static electricity can be quickly removed. To do.

(Vacuum chuck manufacturing method) In addition to cordierite and eucryptite, if necessary, carbon, a carbide of a 4a group element, etc. are mixed and mixed in a solvent such as alcohol or water using a ball mill. . After mixing
Dry to obtain raw material powder. The powder obtained is fired by hot pressing to obtain a dense sintered body. When cordierite is the main material, the firing conditions are 1300 ° C. to 1450 ° C. in an inert gas atmosphere such as nitrogen or argon.
490 Pa to 4900 Pa (50 kgf / cm ² to 50
0 kgf / cm ² ) is preferable, and when using eucryptite as a main material, it is 1150 ° C. or higher in an inert gas atmosphere.
1300 ° C, 490Pa to 4900Pa (50kgf /
cm ^{2 to} 500 kgf / cm ² ) is preferable. When it is desired to mass-produce a large product, the normal pressure sintering method or the high temperature isotropic pressure sintering method (HIP) is used. The obtained sintered body is machined into a desired shape to produce a product.

In the vacuum chuck of the present invention, a plurality of ceramic base materials including a groove-processed ceramic base material are laminated, and the base materials are bonded to each other via a metal-based bonding material layer or an inorganic-based bonding material layer. Therefore, an embodiment in which a cavity is provided in the joint surface portion of the base material is preferable.

As a method of forming the cavity, a method of forming two or more holes from the outer circumference of the vacuum chuck so as to intersect each other inside without joining, or a method of forming no groove with a pre-grooved base material There is a method in which a base material is laminated and bonded to form a base material. This is because the latter joining method is preferable because the shape and size of the cavity to be formed can be easily designed.

The base materials to be laminated can be made of different materials. For example, the base material on the side for vacuum suction of the wafer is woven into the conductive material by taking measures against particles, and the base on the side not related to vacuum suction is used. The material may be an insulating material, or base materials having different Young's modulus and thermal expansion coefficient may be laminated.

There are three types of joining methods: a method using a resin joining material such as an epoxy resin, a method using an inorganic joining material such as glass, and a method using a metal joining material. The method using an inorganic bonding material or the method using a metal bonding material is preferable because the bonding strength is deteriorated, the rigidity of the bonded portion is decreased, and the thermal resistance is increased due to deterioration over time.

In the method of bonding with an inorganic bonding material, glass is typically used as the inorganic bonding material. As the glass, those having a thermal expansion coefficient of 4 × 10 ⁻⁶ / ° C. or less at a temperature of 0 ° C. to 300 ° C. are preferable, and 3 × 10 ⁻⁶
Those having a temperature of / ° C or less are more preferable. When the coefficient of thermal expansion of the glass is larger than 4 × 10 ⁻⁶ / ° C., the base material to be joined is a low thermal expansion material, so that cracks and peeling at the interface are likely to occur due to the difference in thermal expansion between the glass and the base material. Examples of such low thermal expansion glass include borosilicate glass. The thickness of the glass after bonding is preferably 5 μm to 100 μm from the necessity of relaxing stress generated at the bonding interface,
It is more preferably 5 μm to 50 μm.

Although the borosilicate glass itself mentioned here is an insulating material, in the case of a base material having a volume resistivity of 10 ⁵ Ω · cm or less, electrical continuity between the base materials is maintained even after bonding with the borosilicate glass. May be secured. It is considered that this is due to diffusion of the conductive component of the base material such as carbon into the glass.

For joining with glass, glass powder is mixed with a solvent, coated on a substrate, dried and then melted in a firing furnace.
After that, the procedure of solidifying can be performed. Firing
When a non-oxidizing additive is added to the base material, it is preferably carried out in an inert atmosphere such as nitrogen. When the additive has no component that oxidizes or when the additive is not added, firing in an air atmosphere is also possible. For example, when borosilicate glass is used as a bonding material, the firing temperature is 1150 in terms of promoting melting of the glass, eliminating bubbles, avoiding leakage of a cooling medium after bonding, and increasing rigidity of the bonding portion.
C. to 1300.degree. C. are preferred.

In the method using a metal bonding material, for example, a brazing material containing silver as a main component, a brazing material containing titanium as a main component, or an aluminum material is used. The brazing material is preferably selected based on the bonding strength and the corrosion resistance of the cooling medium. In order to surely prevent the leakage of the cooling medium after joining, the brazing material preferably has a uniform coating thickness, and a foil-shaped brazing material having a uniform thickness is more preferable than a paste-shaped brazing material. The thickness of the brazing material is preferably 10 μm to 50 μm, more preferably 10 μm to 30 μm.

In the case of not using the bonding method, after forming a hole from the outer periphery of the vacuum chuck, in the case of the vacuum chuck for an exposure apparatus, a convex portion (pin) or a ring may be provided on the surface holding the wafer. preferable. On the other hand, in the case of the bonding method, the convex portion (pin), the ring or the like may be provided on the surface holding the wafer either before or after the bonding. Further, in order to promote heat exchange with the cooling medium, the shape of the cavity is improved, and in order to remove the heat generated in the wafer, cooling gas is provided between the innumerable convex portions provided on the surface holding the wafer. It is also possible to add additional improvements such as distributing.

[0044] Example purity and an average particle diameter of 99% or more and 3μm cordierite powder and eucryptite powder main material of an average particle diameter of 0.1μm of carbon powder as needed to an average particle size Powders of carbides, nitrides, borides, suicides, boron carbide, silicon carbide, silicon nitride and aluminum nitride of 4a group element, 5a group element or 6 group element of 0.5 μm are shown in Tables 1 to 7 after sintering. After blending so as to have the ratio shown in (1), ethanol was used as a solvent and mixed in a ball mill for 24 hours. The obtained mixture was dried and then hot-press fired at a temperature shown in Tables 1 to 7 under an inert gas atmosphere of nitrogen or argon under a pressure of 4900 Pa (500 kgf / cm ² ) to obtain a porosity of 0.1. % Or less to obtain a dense sintered body. The results of investigating the physical properties of the obtained sintered body are shown in Tables 1 to 7.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

[Table 5]

[0050]

[Table 6]

[0051]

[Table 7]

Abrasion resistance was measured by the pin-on-disk method. If the measured wear resistance is almost the same as the wear resistance of the main material, Δ is given, and if it is superior to the main material, ○ is given.

Regarding conductivity, the volume resistivity is 10 ⁸ Ω.
Those with more than cm are marked with Δ, and those with less than 10 ⁸ Ω · cm are marked with ◯.

As is clear from the results shown in Tables 1 to 7,
The ceramics of the present invention were dense ceramics having a coefficient of thermal expansion with respect to temperature rise of 1.5 × 10 ⁻⁶ / ° C. or less and a porosity of 0.5% or less. Therefore, by using a vacuum chuck that uses such a dense low thermal expansion ceramics as a base material, the thermal expansion is suppressed to a low level even when the temperature rises during wafer processing, and high-precision wafer processing becomes possible. , It was found that it is possible to sufficiently cope with the miniaturization of the circuit.

Using these low thermal expansion ceramic bodies, a vacuum chuck having a cavity inside was produced by bonding. The low thermal expansion ceramic bodies are (a) 100% cordierite product (Example 12 of Table 1), (b) 95% cordierite + 5% WC product (Example 2 of Table 1),
(C) Cordierite 97.5% + carbon 1.5%
Three types of + Si ₃ N ₄ 1.0% product (Example 70 in Table 7) were prepared. Regarding any of these materials, one having a concentric groove formed by processing and one having no groove formed in the other were prepared and joined with a brazing material. The brazing material contained 70% silver, 27% copper, and 3% titanium, and had a foil shape (thickness 20 μm). The heating temperature during brazing was 850 ° C. After joining, finishing processing was performed. In the vacuum chuck thus obtained,
Water of 3 atm was passed through, but no water leaked.

The embodiments and examples disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0057]

The wafer holding vacuum chuck of the present invention is
Suppresses the thermal expansion of the chuck against the temperature rise during processing,
It is possible to keep the temperature of the wafer on the chuck constant. Further, by increasing the rigidity while suppressing the increase in weight of the chuck, it is possible to perform high-precision processing on the wafer, and it is possible to sufficiently cope with the miniaturization of the circuit.

The vacuum chuck of the present invention is useful as a vacuum chuck for an exposure apparatus, a vacuum chuck for a wafer polishing apparatus, etc., and can be used for a liquid crystal manufacturing apparatus as well as a semiconductor manufacturing apparatus.

[Brief description of drawings]

FIG. 1 is a schematic view showing the structure of a vacuum chuck of the present invention.

FIG. 2 is a schematic view showing the structure of another vacuum chuck of the present invention.

FIG. 3 is a schematic view showing the structure of still another vacuum chuck of the present invention.

[Explanation of symbols]

11 convex part, 12 vacuum suction path, 13 cavity, 14
Joint surface.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G030 AA02 AA07 AA36 AA37 AA45                       AA46 AA47 AA49 AA51 AA52                       AA53 AA60 BA01 BA24 CA03                       CA07 CA08 HA18                 5F031 CA02 CA05 HA02 HA08 HA14                       HA38 MA27 PA11                 5F046 CC08 CC10 CC11

Claims (6)

[Claims] 1. A wafer-holding vacuum chuck constituting a semiconductor manufacturing apparatus, having a coefficient of thermal expansion of 1.5 × 10 ⁻⁶ / ° C. or less at a temperature of 10 ° C. to 40 ° C. and a porosity of 0. A vacuum chuck made of low thermal expansion ceramics of 5% or less and having a vacuum suction path and a cavity inside. 2. The vacuum chuck according to claim 1, wherein the Young's modulus of the low thermal expansion ceramics is 120 GPa or more. 3. The vacuum chuck according to claim 1, wherein the low thermal expansion ceramics has a volume resistivity of 10 ⁸ Ω · cm or less. 4. A plurality of ceramic base materials including a grooved ceramic base material are laminated, and the base materials are bonded to each other through a metal-based bonding material layer or an inorganic-based bonding material layer. The vacuum chuck according to claim 1, wherein the cavity is provided in at least one of the bonding surfaces of the respective base materials. 5. The low thermal expansion ceramics comprises 60 vol% to 100 vol% of at least one of cordierite and eucryptite, a carbide, a nitride, a boride of a 4a group element, a 5a group element and a 6a group element, and The vacuum chuck according to claim 1, which is a ceramic containing 0 vol% to 40 vol% of a silicide and at least one selected from the group consisting of boron carbide, silicon carbide, silicon nitride, and aluminum nitride. 6. The low thermal expansion ceramics comprises 57% by volume to 99.89% by volume of at least one of cordierite and eucryptite and 0.
01 vol% to 3 vol%, at least one selected from the group consisting of carbides, nitrides, borides and silicides of 4a group elements, 5a group elements and 6a group elements and boron carbide, silicon carbide, silicon nitride, aluminum nitride The vacuum chuck according to claim 1, which is a ceramic containing 0.1 vol% to 40 vol%.