JPH11235658A - Flattening method and flattening device to be used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always perform stable flattening, instantly correcting or setting an optimum shape on the side of a device according to working shapes of a body to be worked and secular fluctuation of the shape of the body to be worked, even when there are many desired working shapes of the body to be worked and secular fluctuation of the shape of the body to be worked due to deformation of a device itself is generated. SOLUTION: On the rear surface of a revolving working machine 11, each heater 12 and a heat insulating layer 13 covering these heaters 12 are arranged. When current-carrying amount to the heaters 12 is controlled, the working machine 11 deforms according to the heat generation amount, the surface profile of a working surface 11a is changed from flatness → a center recess and also the surface profile of a body 14 to be worked revolving according to this change is changed from flatness → a center projection. Conversely, by directly heating the body 14 to be worked by using the heaters 12 or indirectly heating the body 14 to be worked through a body to be worked holding member, the body 14 to be worked may be thermally deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar processing method capable of quickly and easily setting and maintaining optimum processing conditions in accordance with a target processing shape of a workpiece and its temporal variation, The present invention relates to a flat surface processing apparatus suitably used for the above.

[0002]

2. Description of the Related Art Many mechanical parts have a certain plane, and plane processing for processing this plane with high precision is one of the basic techniques of machining. A typical apparatus for performing plane processing is a lapping machine. This is a machine that performs more precise polishing on a workpiece that has been subjected to rough processing such as lathe processing and grinding processing. FIG. 14 shows a typical configuration example of a lapping machine. FIG. 14 (a) top view, FIG.
(B) is the XX sectional drawing. This machine includes a carrier 95 that performs planetary motion by being engaged with both the sun gear 81 and the inner peripheral gear 84, and a surface plate 87 that is arranged coaxially with the sun gear 81 and performs a unique rotational motion. The workpiece W (work) mounted on the carrier 95 is slid in contact with the surface of the surface plate 87 so that the workpiece W is wrapped.

The sun gear 81 is integrally attached to an upper end of a rotating shaft 82 driven to rotate by a motor 83. The inner peripheral gear 84 is formed at the upper end of a frame 85 surrounding the outer periphery of the surface plate 87, and the frame 85 is a motor 86 controlled independently of the motor 83.
Is driven to rotate. The platen 87 is disposed such that its legs 88 surround the rotation shaft 82, and is independently rotated and driven by a motor 90 at the end of the legs 88. The workpiece W is held so as to be fitted into the opening 96 of the carrier 95. When the workpiece W is brought into sliding contact with the surface of the surface plate 87, that is, the work surface, the polishing slurry L is supplied from a nozzle 94 opened above the work surface to increase polishing efficiency and remove frictional heat. It has been made like that.
A large number of grooves 89 are formed on the surface of the surface plate 87 to guide the excess polishing slurry L to the peripheral portion. Surface plate 8
The polishing slurry L that falls from the peripheral portion of the
1 and stored in a slurry tank 92, pumped by a pump 93 and circulated and reused.

On the other hand, there is a chemical mechanical polishing (CMP) apparatus as an apparatus for performing finishing processing such as mirror polishing with higher accuracy than the above lapping. FIG. 15 shows a typical configuration example of a chemical mechanical polishing apparatus. In this apparatus, a substantially disk-shaped surface plate 101 having a polishing cloth stretched on its surface and a polishing head 110 holding a workpiece W are arranged in parallel and opposed to each other. The surface of the workpiece W is polished by combining the rotation of the polishing head 110 with the rotational movement of the polishing head 110. The polishing mechanism is based on a complex mechanochemical action in which a mechanical process and a chemical process using the polishing slurry L are combined.

The platen 101 has an upper half portion 101t and a lower half portion 101b firmly integrated by using fixing means such as bolts. A groove-like cavity 102 is provided to serve as a cooling water flow path. By circulating the cooling water inside the cavity 102, deformation of the platen 101 due to frictional heat during polishing is prevented, thereby improving the flatness of the workpiece W.
The contact area between the upper half 101t and the lower half 101b, in other words, the cooling area of the platen 101 with the cooling water is
Of the work surface, and is designed to minimize deformation of the surface plate 101 due to a polishing load. Further, the central portion of the bottom surface of the lower half portion 101b is connected to the rotating shaft 103, and is rotated at a constant speed by a driving means (not shown).

[0006] The polishing cloth 105 stretched on the upper surface of the surface plate 101 is a viscoelastic body having an appropriate stickiness and elasticity.
Urethane nonwovens are typically used. The above polishing cloth 10
At the center of the upper surface of 5, for example, colloidal silica as a polishing slurry L is pumped by a pump 108 and supplied from an upper nozzle 109. In addition, a drain receiver 106 for collecting the polishing slurry L overflowing from the edge of the surface plate 101 is provided on the outer periphery of the surface plate 101. The polishing slurry L collected through the drain receiver 106 is temporarily stored in a slurry tank 107, and then is once again pumped.
It is recycled in the form of being pumped at 08.

On the other hand, the head 110 has a workpiece holding plate 112 on its lower surface.
One or a plurality of workpieces W are held on the workpiece 12 by a method such as vacuum suction or wax bonding. The polishing head 110 is also connected to the rotating shaft 113, is driven to rotate at a predetermined rotation speed by a drive mechanism (not shown) attached to the rotating shaft 113, and is pressed against the polishing cloth 105 by a predetermined force. Have been. The workpiece W is, for example, a silicon wafer sliced from a silicon ingot and subjected to lapping, or a substrate on which an insulating film or conductive film having surface irregularities is formed. Polishing of a silicon wafer is mirror polishing performed at the final stage of wafer finishing. Flattening of an insulating film by polishing is an indispensable step for improving the reliability of forming a circuit pattern in a multilayer wiring process. Polishing of a conductive film is a useful process for filling a connection hole with a high aspect ratio opened in an insulating film with a metal plug.

When the workpiece W is polished using the chemical mechanical polishing apparatus having such a configuration, the workpiece W is held between the workpiece holding plate 112 and the surface plate 101 which are parallel to each other. And pressed by a resilient polishing cloth. Therefore, the region of the workpiece W having a large thickness is preferentially removed by receiving a higher contact pressure than the region of a small thickness, and the workpiece W is flattened.

[0009]

The plane of the workpiece W obtained by the above-described lapping machine is not limited to a highly flat surface, but may have a shape in which the center is slightly convex depending on the application (hereinafter, referred to as "the surface"). In some cases, the shape may be a center-convex shape or a shape in which the center is slightly concave (hereinafter, referred to as a mid-concave shape). Therefore, the surface profile of the surface plate 87 also needs to be formed in a shape corresponding to this. That is, when the workpiece W is required to have a convex shape, a concave surface profile is required. When the workpiece W is required to have a concave shape, a convex surface profile is required. Will be.

[0010] These surface profiles of the surface plate are produced by using a special processing tool while adjusting the operating conditions of the lapping machine. Whether or not a desired processing plane can be obtained by using the surface plate 87 is confirmed by actually processing the workpiece W. If the desired processing surface cannot be obtained, the surface profile of the surface plate 87 is recreated. Repeat for adjustment. For this reason, the adjustment work becomes extremely complicated. In addition, since the surface profile of the surface plate 87 is deformed due to abrasion even when the processing of the workpiece W is repeated, it is very disadvantageous in terms of cost and time to perform the adjustment each time.

When the object to be processed is a semiconductor wafer, the situation is more complicated. In the case of a semiconductor wafer, it is necessary to perform processes such as lithography, etching, and thin film formation with high precision in accordance with a fine design rule from submicron to quarter micron and even smaller. In addition,
In a recent plasma apparatus or reduction projection exposure apparatus compatible with fine processing, since a process is performed in a state where a wafer is vacuum-adsorbed to a stage, a slight warp or distortion is corrected.
Therefore, the flatness, which is a problem in the present specification, indicates a degree of variation in the thickness of the wafer.

The mirror polishing of a semiconductor wafer is performed based on a mechanochemical action using a chemical mechanical polishing apparatus as described above. However, such polishing has many factors that affect flatness. For example, the surface roughness of the polishing cloth 105,
Clogging of the polishing pad 105 due to the material removed by polishing, thickness and uniformity of the polishing pad 105, viscoelasticity of the polishing pad 105, polishing pad closely related to frictional heat between the workpiece W and the polishing pad 105 105, and the degree of the polishing slurry L reaching the surface of the workpiece. However, it is difficult to say that the degree of influence of all these factors on flatness has been elucidated and properly controlled. When, for example, a silicon wafer is polished using the conventional apparatus as described above, the silicon wafer generally assumes a shape that is concave toward the center and has a height difference of about 200 mm (8 inches) in diameter between the periphery and the center. Fluctuates with time over a range of about 0.1 to 0.6 μm.

One of the major causes of the formation of the concave shape is the influence of thermal deformation of the surface plate 101. The heat for deforming the platen 101 includes frictional heat generated by sliding between the workpiece W and the polishing cloth 105 and frictional heat generated by a polishing load applied to the polishing cloth 105 from the workpiece W. . Part of the frictional heat generated by the rubbing between the workpiece W and the polishing cloth 105 is part of the surface of the polishing cloth 105 → the main body of the polishing cloth 105 → the surface of the surface plate 101 → the back surface of the surface plate 101 → the surface of the surface plate 101. The scale adheres to the cavity 102 constituting the back surface → the boundary layer of the cooling water → the main body of the cooling water, and is removed along the route. The calorific value varies depending on factors related to the type of the polishing cloth 105 such as surface roughness, dynamic friction coefficient, and clogging state, or process conditions such as polishing time, polishing pressure, and polishing rate. On the other hand, a part of the frictional heat generated by the polishing load applied to the polishing pad 105 from the workpiece W is unevenly distributed on the polishing pad 105. Moreover, the polishing cloth 10 serving as a conduction path of the frictional heat to the cooling water is provided.
The thermal conductivity of No. 5 varies depending on the clogging condition, and the thickness of the scale attached to the inner wall of the cavity 102 and the thermal conductivity of the boundary layer vary depending on the flow rate of the cooling water. Due to these factors, the surface of the platen 101 actually has an extremely complicated shape.

Further, since the upper half portion 101t and the lower half portion 101b of the platen 101 are firmly connected mechanically, their respective thermal deformations affect each other. Further, since the cooling area of the upper half 101t of the surface plate 101 by the cooling water is as small as about half of the total area of the work surface, the ability to remove frictional heat is limited. These factors overlap and the surface plate 10
1 to increase the amount of thermal deformation of the upper half 101t,
5 promotes an increase in the surface temperature and uneven distribution, and finally causes deterioration of the flatness of the workpiece W.

Accordingly, the present invention provides a method for forming a desired shape of a workpiece even when the shape of the workpiece varies with time due to the deformation of the apparatus itself. It is an object of the present invention to provide a plane processing apparatus capable of immediately correcting the surface profile of the apparatus required for obtaining a surface, and a method capable of always performing stable plane processing using the apparatus.

[0016]

According to the present invention, there is provided a plane machining method for producing a desired plane while bringing a rotating workpiece into sliding contact with a working surface of the rotating machining board. The object described above is achieved by thermally controlling at least one of the surface profile of the surface, the surface profile of the workpiece, and the surface profile of the workpiece holding surface of the polishing head that holds the workpiece. What you want to do. The above control can be easily performed by using a heating means, but the cooling by a cooling means may be used together to increase the degree of freedom and accuracy of the control. During the sliding contact, an abrasive may be supplied on the work surface, and a polishing cloth may be stretched on the work surface to perform chemical mechanical polishing.

A plane processing apparatus according to the present invention, which is suitable for carrying out such a plane processing method, comprises: a rotary processing board; and a rotary polishing head for holding a workpiece facing a work surface of the processing board. Heating means for thermally changing the surface profile of the processing board, heating means for thermally changing the surface profile of the processing object, or the processing object At least one of heating means for thermally changing the surface profile of the workpiece holding surface of the polishing head to be held is provided. The above-mentioned processing board may be constituted by a joined body of an upper half having a work surface and a lower half which is brought into contact with the flat heater. Furthermore, the upper half may consist of a group of rigid blocks which are adjacent to each other via a layer of elastic material and which are individually joined to the lower half in a portion which covers substantially the entire working surface. The planar processing apparatus of the present invention may be provided with a cooling means in addition to the heating means. Further, the work surface may be provided with abrasive supply means for supplying an abrasive, and a polishing cloth may be stretched on the work surface so as to be suitable for chemical mechanical polishing. Good.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have made basic considerations on the thermal deformation of a disc in proposing the present invention. The model used for this consideration is shown in FIG. Here, a polishing cloth 2 is stretched on the front surface of the disk 1, and a cooling water channel 3 is formed on the back surface. On this back surface, a scale layer 4 is attached and formed. On the surface of the scale layer 4, there is a thin boundary layer 5 which is a transition region from laminar flow to turbulent flow, and the outside of the boundary layer 5 is free. There is cooling water 6 flowing in the air.

Now, assuming that the disk 1 is uniformly heated from the observation surface side (here, the polishing cloth 2 side), the thermal deformation ΔF from the reference surface S is expressed by the following equation (I). .

[0020]

(Equation 1)

Where α is the coefficient of linear expansion of the disk (1/1 /
° C) λ: Thermal conductivity of the disc (cal / mm · sec · ° C) D: Diameter of the disc (mm) Q: Heat transfer density of the disc (cal / mm ² ) H: Thickness of the disc ( mm) λc: Thermal conductivity of polishing cloth (cal / mm · sec · ° C) Hc: Thickness of polishing cloth (mm) Tc: Surface temperature of polishing cloth (° C) λs: Thermal conductivity of scale (cal / mm) Hs: Scale thickness (mm) Ts: Scale surface temperature (° C) f: Boundary layer heat transfer coefficient (cal / mm ² · second · ° C) Tw: Cooling water temperature (° C) The sign of ΔF is plus (+) when the disk 1 is convex on the observation surface side, and the sign of Q is plus (+) when heat flows from the observation surface side to the opposite surface side. .

From the equation (I), it can be seen that the shape of the surface of the deformed disk 1 is approximated by a paraboloid. Here, α and λ depend on the constituent material of the disk 1, and D and H are constants because they are the dimensions of the disk 1. In contrast, T
w and Ts vary depending on the processing conditions, Hc and λc vary depending on the clogging state and the constituent material of the polishing pad 2, Hs and λs vary depending on the adhesion state of the scale layer 4, and f varies depending on the flow rate of the cooling water 6. Therefore, the terms that are considered to be able to reflect the artificial control on ΔF relatively easily are Q and Tw. However, it is clear that ΔF can be more accurately controlled by controlling Q without any fluctuation factors.

The above considerations relate to the model in which the disk 1 is in contact with the cooling water flow path 3. For the disk 1 not in contact with the cooling water flow path 3, the scale layer 4 is obtained from the above equation (I). The terms related to the boundary layer 5 and the cooling water 6, that is, λs, Hs, Ts, f, and Tw may be deleted, and the basic concept is the same. When the polishing cloth 2 is not stretched on the surface of the disk 1, the terms related to the polishing cloth 2, that is, λc, Hc, and Tc may be deleted. Further, the disk body 1 may be considered as any of a processing board, a workpiece, and a polishing head for holding the workpiece. The present invention is based on such considerations, that is, the surface profile of the working surface of the processing board, the surface profile of the workpiece,
Alternatively, at least one of the surface profiles of the workpiece holding surface of the polishing head that holds the workpiece is thermally controlled. This thermal control can be performed by adjusting the amount of power to a heating means provided on at least one of the processing board, the back surface of the workpiece, and the polishing head.

FIGS. 2 to 4 conceptually show a configuration for realizing these controls. Here, in consideration of a more practical configuration, each of the heaters as the heating means is covered with a heat insulating material layer. FIG. 2 shows the working surface 1 of the processing board 11.
A state is shown in which a heater 12 as a heating means is in contact with the surface opposite to 1a, and this heater 12 is further covered with a heat insulating material layer 13. By covering the heater 12 with the heat insulating material layer 13, the direction of the heat flow can be defined from the heater 12 to the work surface 11a, and the heating efficiency can be increased.

FIG. 3 shows a state in which a heater 12 is brought into contact with a surface of a workpiece 14 opposite to a surface 14a to be processed.
Shows a configuration further covered with a heat insulating material layer 13.
This configuration is suitable when the workpiece 14 is a thick plate body. For example, when processing a workpiece holding surface (hereinafter, referred to as a holding surface) of a workpiece holding member described below. Can be applied to In this specification, the term "thick plate" means that even if an adjacent member that causes thermal deformation is in contact with one main surface, the change in its own surface profile due to the deformation is negligible. It refers to a plate that does not occur. In order to change the surface profile of such a thick plate, it is necessary to directly heat the thick plate itself, not the adjacent members.

FIG. 4 shows that the workpiece 14 is held on the holding surface 15 a of the workpiece holding member 15.
The heater 12 is in contact with the surface on the side opposite to
2 shows a configuration further covered with a heat insulating material layer 13. Such a configuration is suitable when the workpiece 14 is a thin plate, and can be applied, for example, when processing a semiconductor wafer. In the present specification, “thin plate body” means that when an adjacent member that causes thermal deformation is in contact with one main surface, its own surface profile changes under the influence of the deformation. It refers to a plate.

The heater 12 is preferably a flat heater. Specifically, for example, a silicone rubber heater in which a resistance heating element such as a nichrome wire is covered with a flexible insulator such as silicone rubber can be used. It is preferable that the plane heater has as uniform a heat generation density distribution as possible. In addition, if a transformer is interposed between the flat heater and the power supply, the amount of heat can be adjusted by controlling the amount of current supplied to the flat heater by the transformer. By adjusting the calorific value, the surface profile of the working surface of the processing board, the workpiece, or the workpiece holding member of the polishing head that holds the workpiece can be changed quickly, easily, and reversibly. In particular, with regard to a processing board and a polishing head, the work of adjusting the surface profile using a conventional processing tool is not required, which is extremely advantageous in terms of cost and time.

FIGS. 5 and 6 show the processing machine 1 shown in FIG.
A state in which the surface profile of the first work surface 11a changes due to heating, and the final processing shape of the workpiece 14 changes accordingly. Here, the processing board 11 and the workpiece 14 are rotating around their respective center lines as indicated by arrows A and B. FIG. 5A shows an initial state in which the heater 12 is not energized and the work surface 11a is flat, and FIG. 5B shows a state in which the work surface 11a is deformed into a concave shape by energization of the flat heater 12, and FIG. (c) shows a state in which the amount of deformation of the work surface 11a is further increased due to an increase in the amount of electricity. Along with this, the surface profile of the workpiece 14 also changes from flat in FIG. 5 (a) to central convex in FIG. 5 (b) and further to large central convex in FIG. 5 (c). Alternatively, as shown in FIG. 6 (a), the initial state of the work surface 11a is set to be convex in the middle, and this shape is canceled out by the deformation in the concave direction due to energization and flattened as shown in FIG. 6 (b). Profile can be obtained. Along with this, the surface profile of the workpiece 14 changes from the middle concave in FIG. 6A to the flat in FIG. 6B.

FIGS. 5 and 6 show the case where the surface profile is changed only on the processing board 11, but the same change may be applied to the workpiece 14 as shown in FIG. Alternatively, as shown in FIG. 4 described above, the workpiece may be provided on the holding surface 15a of the workpiece holding member 15, or the changes may be combined.

In order to obtain a desired processed shape of a workpiece using these planar processing apparatuses, first, planar processing is performed under certain conditions, and the shape of the obtained workpiece is measured. At this time, a difference between the measured shape and the target shape is obtained, and thermal deformation is applied to at least one of the processing board 11, the workpiece 14, or the workpiece holding member 15 so that the difference can be corrected. I do. In the plane processing method of the present invention,
These series of steps will be repeated until a desired shape is obtained.However, since thermal deformation can be freely caused by adjusting the amount of electric current, for example, using a dedicated processing tool as in the related art, There is no need to rework the workpiece holding member, which is extremely advantageous in terms of cost and time.

[0031] The processing board may be constituted by a joined body of an upper half having a working surface and a lower half contacting the flat heater. In addition, the upper half may be a collection of rigid blocks in which portions substantially all over the working surface are adjacent to each other via an elastic material layer and are individually joined to the lower half. These configurations also relate to the ease of forming a cavity for cooling water distribution described below. By the way, in the planar processing method of the present invention, the cooling by the cooling means may be used together with the control of the surface profile. If cooling is used in combination, a part of the heat generated by the above-mentioned heating means will be taken away by this cooling, which is disadvantageous from the viewpoint of effective use of heat.However, since control parameters related to cooling increase, More accurate surface profile control becomes possible.

An example of such a cooling means is a refrigerant circulation system, a typical example of which is to circulate cooling water. FIG. 7 shows a configuration example of a processing board 11 in which cooling water is circulated. The processing board 11 is formed by integrally joining an upper half 11t having a working surface 11a and a lower half 11b to which the heater 12 is brought into contact. Cavity 16 is formed. The cavity 16 is formed, for example, in a spiral shape, and a cooling water pipe 18 inserted into a leg 17 which is a rotation shaft of the processing board 11 is connected to both ends of the cavity 16.

FIG. 8 shows an example in which the upper half 11t of the processing board 11 is composed of an aggregate of a plurality of rigid blocks 20.
Each rigid block 20 has a leg 20a at the lower end and a flange 20b at the upper end.
Are arranged adjacent to each other with the seal member 21 interposed therebetween, thereby forming one working surface 11a as a whole. The plurality of rigid blocks 20 are individually joined to the lower half 11b at the legs 20a. The flange portion 20b in the work surface 11a
Although the plane shape of is not particularly limited, the work surface 1
From the viewpoint of filling 1a with a gap as small as possible, a rectangle or a hexagon is preferred. In the above configuration, the cavity 22 surrounded by the adjacent rigid block 20, the elastic sealing material 21, and the lower half portion 11b serves as a flow path of the cooling water. These cavities 22 need to be connected to each other by an appropriate route, and the through holes 20c provided in the leg portions 20a serve for this connection.

According to the block integrated structure, even if the individual rigid blocks 20 undergo thermal deformation due to frictional heat during the planar processing, they are absorbed by the elastic sealing material 21, so that the entire work surface 11a is As a result, the initially set surface profile can be maintained as it is. That is, the thermal deformation of the lower half part 11b is directly reflected on the surface profile of the work surface 11a without being disturbed. Further, since the cavities 22 are provided adjacent to the individual rigid blocks 20 to secure a large total cooling area, the cooling capacity is sufficient. Note that the above-described block integrated structure does not necessarily have to have a cavity, and for example, each rigid block may have a simple columnar shape. Even with such a configuration, the lower half 11
The effect of faithfully reflecting the thermal deformation of bg on the surface profile of the work surface 11a can be expected.

Incidentally, in the present invention, in addition to the above-described refrigerant circulation system, a thermoelectric cooling element can be used as a cooling means. A thermoelectric cooling element is an element that utilizes the Peltier effect in which heat is absorbed when a current is applied to a contact of a dissimilar metal. When using a heating means such as a flat heater,
If such a thermoelectric cooling element is used as cooling means, both heating and cooling can be performed electrically, and the device configuration can be simplified. The thermoelectric cooling element can also be used as a heating element if the direction of current flow is reversed, so it can be used as a heating means instead of a flat heater, or it can be used for both heating and cooling It is. In the latter case, for example, a configuration is possible in which two electric circuits of thermoelectric cooling elements are provided, and current flows in one circuit in a direction in which heat is generated and in the other circuit in a direction in which heat is absorbed. However, the thermoelectric cooling element originally has local cooling /
Since the element is suitable for heating, it is better to use a flat heater for heating a large area, because the element has better thermal efficiency.

In the present invention, when the workpiece is brought into sliding contact with the work surface of the processing board, an abrasive may be supplied onto the work surface to polish the workpiece. Any conventionally known abrasive can be used, and typically, colloidal silica is used. In particular, by providing a polishing cloth over the work surface of the processing board, and by providing abrasive supply means for supplying an abrasive to the surface of the polishing cloth, a planar processing apparatus that performs chemical mechanical polishing of the workpiece. Can be provided. Such an apparatus is particularly useful when the workpiece is a semiconductor wafer.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

Embodiment 1 In this embodiment, an example of the configuration of a chemical mechanical polishing apparatus having a heater and a heat insulating material layer on both the back surface of a processing board and the back surface of a workpiece holding member of a polishing head will be described with reference to FIG. This will be described with reference to FIG. This apparatus includes a disk-shaped processing board 11 having a polishing cloth 19 stretched on a work surface 11a, and a workpiece 14
Polishing head 3 for holding a semiconductor wafer, for example
5 are arranged in parallel and opposed to each other, and the rotation of the processing board 11 in the direction of the arrow A and the rotation of the polishing head 35 in the direction of the arrow B are combined to change the surface of the semiconductor wafer in the presence of the polishing slurry. It is designed for chemical mechanical polishing.

The processing board 11 is made of SUS having a thickness of 30 mm.
The upper half 11t made of a steel plate and the S
This is a disk having a diameter of 700 mm, which is firmly integrated with the lower half 11b made of a US steel plate using fixing means such as bolts. A part of the joint surface between the upper half 11t and the lower half 11b is formed as a cavity 16 and serves as a cooling water flow path. As shown by an arrow A, the processing board 11 is rotated around a leg 17 connected to the center of the lower half portion 11b using a driving means (not shown). The leg 17 also serves as a passage of a cooling water pipe 18 for introducing cooling water into the cavity 16, and the cooling water pipe 18 passes through a rotary joint 34 provided at an intermediate portion of the leg 17. And is led out. The cooling area of the cavity 16 is about 70% of the area of the work surface 11a, where the temperature is 20 ° C. and the flow rate is 5 liter /
Cooling water was flushed in minutes.

A heater 12a was brought into contact with the back side of the lower half portion 11b, and the heater 12a was further covered with a heat insulating material layer 13a. ＾
As the heater 12a, for example, a nichrome wire is coated with a silicon rubber layer, and a 0.6 W /
A plurality of silicon rubber heaters capable of producing a heat density of ² cm ² were connected in parallel and used. The wiring of the heater 12 passes through the inside of the leg 17, is led out through a rotary connector 31 provided in the middle of the leg 17, and is connected to a power supply 33 through a transformer 32. . By operating the transformer 32, the amount of electricity supplied to the heater 12a, that is, the amount of generated heat can be easily and quickly changed. The heat insulating material layer 13 has a thickness of 6 as an example.
mm silicone rubber foam was used.

As the polishing pad 19 stretched on the work surface 11a, a urethane nonwoven fabric was used. In the upper center of the processing board 11, a nozzle 45 for supplying the polishing slurry is opened. As the polishing slurry, for example, colloidal silica is supplied to the surface of the polishing cloth 19. A drain receiver for collecting the polishing slurry overflowing from the edge of the processing board 11, a tank for storing the collected polishing slurry, and a pump for pumping the polishing slurry to the nozzle 45 are not shown. However, this is as described with reference to FIG.

On the other hand, the polishing head 35 is
A workpiece holding member 15 and a suction jig 40 are provided at the center of the bottom surface of the workpiece 1 as workpiece holding members.
The work piece 14 is pressed against the polishing pad 19 with a predetermined pressure by applying air pressure while adsorbing and holding the work piece 4 on the work piece holding member 15 by vacuum evacuation.
The wall of the pressurizing chamber 36 is a member forming a skeleton of the polishing head 35, and is rotated by a driving unit (not shown) around a leg 37 connected to the center of the ceiling as shown by an arrow B. . The leg 37 also functions as an air pipe 39 for introducing air into the pressurizing chamber 36, a vacuum pipe 41 connected to a suction jig 40 described later, and a wiring path for a heater 12b described later.

The workpiece holding member 15 is, for example, a porous alumina ceramic plate having a diameter of 210 mm and a thickness of 30 mm, and one surface thereof has a holding surface 15 a for holding the workpiece 14, and the holding surface 15 a The surface on the opposite side is the mounting surface of the suction jig 40. The suction jig 40 is, for example, a SUS steel plate having a diameter of 210 mm and a thickness of 2 mm.
It has a large number of grooves serving as air suction paths. This groove is connected to the above-mentioned vacuum pipe 41, and this vacuum pipe 41
Is led out through a rotary joint 38 provided in the middle of the leg portion 37,
It is connected to a vacuum pump (not shown).

On the back surface of the suction jig 40, a heater 12b and a heat insulating material layer 13b are provided. These are processing board 1
1 is the same as that mounted on the lower half 11b. The wiring of the heater 12b also passes through the inside of the leg 37,
It is led out through a rotary connector 42 provided in the middle thereof and connected to a power supply 44 via a transformer 43. By operating this transformer 43,
The amount of electricity supplied to the heater 12b, that is, the amount of heat generated can be changed easily and quickly. With this configuration, the present apparatus can be used to perform single thermal deformation of the processing board 11, single thermal deformation of the workpiece 14, or simultaneous thermal deformation of the processing board 11 and the workpiece 14,
The following three types of control are possible.

Embodiment 2 In this embodiment, only the heater 12b on the polishing head 35 side of the apparatus described in Embodiment 1 is operated, and the chemical mechanical polishing of the silicon wafer is actually performed while changing the voltage applied to the heater 12b. In this case, the deformation amount of the wafer surface was examined. The silicon wafer used as the polished sample was cut out from the ingot and then wrapped to a diameter of 2
This is a 00 mm wafer. The polishing conditions were, for example, polishing pressure = 300 g / cm ² , sliding speed = 45 mm / min, and colloidal silica was used as the polishing slurry.
The voltage applied to the heater 12b was changed in the range of 0 to 40V. The deformation amount of the polished silicon wafer was measured in a non-contact manner using a laser type shape measuring instrument. In addition, the surface profile of the work surface 11a of the processing board 11, and the workpiece holding member 1 when the heater 12b is not energized.
The surface profiles of the holding surfaces 15a of No. 5 are all flat.

FIG. 10 shows the results. In this figure, the deformation amount (μm) of the wafer surface is plotted against the applied voltage (V) to the heater 12 b on the back side of the workpiece holding member 15. Here, the amount of deformation is a numerical value indicating how much the edge of the semiconductor wafer has risen or decreased with respect to the plane, and if the edge is higher than the center, the recess is concave, and the end is higher than the center. If it is low, it is convex. If it is the same, it is flat. When the heater 12b was not energized, the semiconductor wafer had a 0.2 μm middle concave shape. This indicates that the surface of the semiconductor wafer cannot always be processed to be flat even if the surface profiles of the working surface 11a of the processing board 11 and the holding surface 15a of the workpiece holding member 15 are both flat. However, as the voltage applied to the heater 12b is increased, the surface profile of the holding surface 15a of the workpiece holding member 15 changes from flat to concave, and accordingly, the surface profile of the semiconductor wafer becomes concave to flat. → It became clear that it changed to a convex center.
According to FIG. 10, the applied voltage that can make the surface profile of the semiconductor wafer just flat is around 20V. Incidentally, the surface profile of the holding surface 15a of the workpiece holding member 15 at this time was slightly concave.

Embodiment 3 In this embodiment, the upper half portion 11t of the processing board 11 is made into a block-integrated structure, and the surface profile of the work surface 11a is controlled with high accuracy by using a cooling water flow passage formed therein. The semiconductor wafer was polished using a chemical mechanical polishing apparatus that was enabled. First, the configuration of the used apparatus is shown in FIG.
This apparatus corresponds to an apparatus in which the processing board 11 shown in FIG. 8 described above is incorporated in the chemical mechanical polishing apparatus shown in FIG. 9 and has the same reference numerals.

Here, each rigid block 20 constituting the upper half 11t is 50 mm long, 50 mm wide and 30 mm thick.
By machining one side of a SUS steel sheet of
A square pillar-shaped leg 20a of 0 mm square and a square flange 20b of 50 mm square are formed, and a lateral through hole 20c is formed in the leg 20a. This rigid block 20 has a diameter of 700 mm and a thickness of 30 mm.
A large number of the SUS steel plates were closely arranged on the lower half portion 11b made of a SUS steel plate having a thickness of 1 mm, and individually fixed using bolts. Work surface 11 constituted by these many rigid blocks 20
a was flattened using an appropriate processing tool, and a gap between the blocks was filled with a silicone rubber-based sealing material 21.

According to the above configuration, the gap between the legs 20a of the adjacent rigid blocks 20 becomes the cavity 22, which is used as a cooling water flow path.
This is approximately 170% of the area of the work surface 11a. This cavity 2
2 is connected to the leg 1 of the processing board 11.
7, and is led out to the outside via a rotary joint 34 provided at an intermediate portion thereof. Further, the wiring of the heater 12b abutting on the lower half portion 11b also passes through the inside of the leg portion 17 of the processing board 11 and is led out to the outside via a rotary connector 31 provided at an intermediate portion thereof. Is connected to the power supply 44 via the. Since the other members have the same reference numerals as those in FIGS. 8 and 11, detailed description is omitted.

Next, the upper half 11 constructed as described above
A polishing cloth 19 made of urethane non-woven fabric is stretched on the surface of t, and the heater 12b on the polishing head 35 side and the heater 12a on the processing board 11 are both turned off.
The cooling water whose temperature has been adjusted was circulated at a flow rate of 5 L / min. In this state, a silicon wafer having a diameter of 200 mm was continuously polished at a polishing pressure of 300 g / cm ² and a sliding speed of 45 m / min. When the thickness distribution of the entire surface of the polished wafer was measured using a capacitance-type flatness measuring device, it was found to be spherical and concave, and the central portion of the wafer was 0.35 μm thinner than the edge.

Therefore, in order to make the thickness distribution of the wafer uniform, a voltage of 10 V is applied to the heater 12a of the processing board 11, and the working surface 11a is placed in a concave direction in the sliding contact area of the silicon wafer having a diameter of 200 mm. It was deformed by 35 μm. The applied voltage is a value theoretically calculated from the coefficient of linear expansion α of the processing board 11, the thermal conductivity Q of the processing board 11, and the characteristics of the heater. The silicon wafer was polished again under the same conditions except for the applied voltage. When the surface of the polished wafer was measured using a flatness measuring device, no concave or convex shape was generated, and it was confirmed that the surface was highly planarized, and the effect of the present invention was proved. .

Embodiment 4 In this embodiment, referring to FIG. 12, an example of the construction of a lapping machine provided with a heater and a heat insulating material layer on both the back surface of the processing board and the back surface of the workpiece holding member of the polishing head will be described. I will explain while. This machine includes a carrier 64 that performs planetary motion by being engaged with both the sun gear 51 and the inner peripheral gear 54, and a processing board 57 that is arranged coaxially with the sun gear 51 and performs a unique rotational motion. The workpiece 14 mounted on the carrier 64 is slid in contact with the surface of the surface plate 57 so that the workpiece 14 is wrapped.

The sun gear 51 is integrally attached to the upper end of a rotating shaft 52 driven by a motor 53. The inner peripheral gear 54 is formed at the upper end of a frame 55 surrounding the outer periphery of the processing board 57.
Is driven to rotate by a motor 56 controlled independently of the motor 53. The processing board 57 has a diameter of 1400 mm,
A disc body made of spheroidal graphite cast iron having a thickness of 70 mm. A leg 58 is connected to the center of the back surface so as to surround the rotation shaft 52, and is independently driven by a motor 53 at the end of the leg 58. It has been made to be. In addition, a large number of grooves 59 are formed on the surface of the processing board 57 to guide excess polishing slurry to the periphery. Since the circulation and reuse system of the polishing slurry is the same as the conventional system, the illustration is omitted. Further, the heater 12 is provided on the back surface of the processing board 57.
a, and the heater 12a further includes a heat insulating material layer 13a.
Covered. These heater 12a and heat insulating material layer 13a
This is the same as that used in the first and third embodiments. The wiring from the heater 12a is connected to the legs 58 of the processing board 57.
And is led out through a rotary connector 61 provided in the middle thereof, and is connected to a power supply 63 via a transformer 62.

The workpiece 14 is held by being fitted into an opening 65 on the bottom surface of the carrier 64. The heater 12 is provided on the back side of the workpiece 14, that is, on the surface opposite to the workpiece surface.
b, and the heater 12b further includes a heat insulating material layer 13
b. A support member 66 is arranged on the back surface side of the heat insulating agent layer 13b, and the wiring from the heater 12b passes through the support member 66, and is led to the outside via the rotary connector 67. The wiring led out is connected to a power supply 69 via a transformer 68. With such a configuration, the present lapping machine is capable of independently deforming the processing board 57,
This enables three types of control, that is, independent thermal deformation of the workpiece 14 or simultaneous thermal deformation of the processing board 57 and the workpiece 14.

Fifth Embodiment Here, only the heater 12a on the processing board 57 side of the lapping machine described in the fourth embodiment is operated to change the applied voltage to the heater 12a, and the basics relating to the deformation of the working board 57 are changed. Study was conducted. Here, the amount of deformation of the processing board 57 when the voltage applied to the heater 12a was changed in the range of 0 to 10 V was measured in a non-contact manner using a laser shape measuring instrument. The initial surface profile of the working surface of the processing board 57 when the heater 12a is not energized has a diameter 140
The entire processing board 57 of 0 mm has a central convexity of 10 μm.

FIG. 13 shows the results. This figure shows the processing board 5
7 is a plot of the amount of deformation (μm) of the working surface of the processing board 57 with respect to the applied voltage (V) to the heater 12a on the back surface side of FIG. Here, the amount of deformation is a numerical value indicating how much the end of the processing board 57 rises or falls with respect to the plane, and if the end is higher than the center, the concave is
If the end is lower than the center, it is convex, and if the end is the same, it is flat.
It is clear from the figure that as the voltage applied to the heater 12a is increased, the surface profile of the processing board 57 changes from central convex to flat to central concave. It was confirmed that this tendency of the change was in good agreement with the quadratic function shown in the above-mentioned theoretical formula (I).

Next, actual processing was performed using the above-described lapping machine. The workpiece 14 has a diameter of 600 mm and a thickness of 20 mm.
It is a thick plate made of alumina ceramic having a thickness of 5 mm, and is aimed at finishing one surface profile into a convex spherical shape of 5 μm. As the polishing slurry L, SiC
(Silicon Carbide) A material obtained by dispersing abrasive grains in water together with additives such as a rust preventive and a surfactant was used. The polishing load was only the total weight of the workpiece 14, the heater 12b, the heat insulating layer 13b, the support member 66, and its accessories.

The voltage applied to the heater 12a on the back side of the processing board 57 was determined from FIG. 13 so that the surface of the processing board 57 had a concave spherical shape having the same curvature as the target shape of the workpiece 14. . That is, since the amount of deformation of the disc is generally proportional to the square of the diameter, the workpiece 14 having a diameter of 600 mm is 5 μm.
The curvature when deformed is a processing plate 57 having a diameter of 1400 mm.
Is equal to the curvature when deformed by 27 [= 5 × (1400/600) ² ] μm. In addition, if the target profile of the workpiece 14 is a convex spherical surface, the surface profile of the processing board 57 corresponding to the target profile is a concave spherical surface, and the sign of the deformation amount is minus. According to FIG. 13, the applied voltage when the amount of deformation of the processing board 57 becomes −27 μm is 10V.

When the workpiece 14 was wrapped under the above conditions, the surface profile became a convex spherical shape of 7 μm, which exceeded the target by 2 μm. The cause of this difference was considered to be a heat storage effect due to the polishing slurry L flowing along the groove 59 and other factors in addition to the surface profile of the processing board 57. Therefore, the processing board 5 actually required
The deformation amount of 7 is the target deformation amount of the workpiece 14 for convenience.
(= 5-2) μm and can be calculated, and −1
6 μm [= −3 × (1400/600) ² ]. This deformation amount can be achieved with an applied voltage of 8 V as shown in FIG.
Then, when lapping was performed again under the same conditions except that the applied voltage was reduced to 8 V, a 5 μm convex spherical surface profile of the workpiece 14 could be obtained as desired for the workpiece 14. As described above, in the present invention, the surface profile of the processing board can be changed very easily by thermal control, and there is no need to repeat a complicated adjustment operation using a processing tool as in the related art.

Although the present invention has been described with reference to the five embodiments, the present invention is not limited to these embodiments. For example, in the above-described embodiment,
Also, the processing example in which a heater and a heat insulating material layer are provided on the side of the polishing head and the carrier, and the heater on one side is energized, has been described. It is also possible to obtain an optimal surface profile for the processing shape of the above. Further, the heater does not necessarily need to be provided on both the processing board side and the polishing head or carrier side as shown in FIGS. 9, 11 and 12, and may be provided on any one of them. The number of workpieces that can be processed at one time by the planar processing apparatus of the present invention is not limited to one, and a plurality of workpieces may be mounted on a polishing head or a carrier.

Further, the planar processing apparatus of the present invention does not necessarily need to combine a relatively large processing board and a small polishing head as described above. For example,
For equipment that holds a workpiece between two large processing boards and performs double-side polishing, a heater and a heat insulating material layer are installed on at least one of these processing boards to optimize the same surface profile. Can be performed. In addition, the apparatus configuration, dimensions, shapes and specifications of each part, the type of workpiece, and processing conditions can be appropriately selected, changed, and combined.

[0062]

As is apparent from the above description, in the planar processing method and the planar processing apparatus of the present invention, the work surface of the processing board, the workpiece, or the workpiece holding of the polishing head for holding the workpiece. Since at least one of the surface profiles of the members is thermally controlled, the time and effort of re-creating the surface profile of the processing board using a special processing tool, for example, according to the processing result of the workpiece as in the past, etc. Can be omitted, greatly contributing to the improvement of processing accuracy and productivity. The above-described thermal control can be performed quickly and easily by adjusting the amount of electricity supplied to the heating means. The workpiece can be directly heated if it is a thick plate, or indirectly through a workpiece holding member if it is a thin plate, to change its surface profile. As a thin workpiece, a process using a semiconductor wafer has high practical value.

When the cooling by the cooling means is used together,
More precise control can be performed by increasing the control parameters. In terms of the device configuration, it is preferable that the processing board be an integrated structure of the upper half and the lower half, and a cavity is provided in a part of the joint surface and the cavity is used as a cooling water flow path. In addition, if the upper half is an aggregate of a large number of rigid blocks adjacent to each other via an elastic material layer, and these rigid blocks are individually fixed to the lower half, frictional heat generated at the time of processing can be used. The thermal deformation of the upper half can be minimized, and only the thermal deformation intentionally applied to the lower half can be substantially reflected in the upper half, which is effective in improving control accuracy. Further, if the gap between the blocks is used as a cooling water flow path, the cooling area can be increased. If the abrasive is supplied when the workpiece is brought into sliding contact with the work surface,
Polishing efficiency can be increased. Depending on the combination of the workpiece and the abrasive, chemical mechanical polishing by mechanochemical action is also possible, which is particularly suitable for polishing a semiconductor wafer.

The present invention is not limited to a process for obtaining a desired surface profile such as a center convex or a center concave for a workpiece,
It is possible to cope with planar processing that requires a high degree of flatness, such as polishing of semiconductor wafers, without significantly changing existing manufacturing equipment and work procedures, and its industrial value is extremely high It is.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a thermal deformation model of a disk.

FIG. 2 is a schematic cross-sectional view showing a configuration in which a heater and a heat insulating material layer are arranged on a surface of the processing board opposite to a work surface.

FIG. 3 is a schematic cross-sectional view showing a configuration in which a heater and a heat insulating material layer are arranged on a surface of a workpiece opposite to a processing surface.

FIG. 4 is a schematic cross-sectional view showing a configuration in which a heater and a heat insulating material layer are arranged on the back surface of a workpiece holding member that holds a workpiece.

5A and 5B are schematic cross-sectional views illustrating a change in a processing shape of a workpiece according to a change in a surface profile of a work surface of a processing board whose initial state is flat, and FIG.
(B) shows the case where the heat generation of the heater is small, and (c) shows the case where the heat generation of the heater is large.

FIG. 6 is a schematic cross-sectional view showing a change in a processing shape of a workpiece according to a change in a surface profile of a working surface of a processing board whose center is convex in an initial state, and FIG. , (B) show the case where the heater generates heat, respectively.

FIG. 7 is a schematic cross-sectional view showing a configuration example of a processing board provided with a cavity for cooling water distribution in a part of a joining surface between an upper half and a lower half.

FIG. 8 is a schematic cross-sectional view showing a configuration example of a processing board whose upper half is composed of an aggregate of a plurality of rigid blocks.

FIG. 9 is a schematic cross-sectional view showing a chemical mechanical polishing apparatus in which a heater and a heat insulating material layer are respectively disposed on the back surface of a processing board and the back surface of a workpiece holding member as one configuration example of the planar processing device of the present invention. It is.

10 is a graph showing a relationship between a voltage applied to a heater behind a holding plate of a workpiece holding member and an amount of deformation of a surface of a wafer in polishing of a silicon wafer using the chemical mechanical polishing apparatus of FIG. 9; is there.

FIG. 11 shows another example of the configuration of the planar processing apparatus of the present invention.
FIG. 3 is a schematic cross-sectional view showing a chemical mechanical polishing apparatus in which an upper half of a processing board is formed of an aggregate of a plurality of rigid blocks.

FIG. 12 is a schematic cross-sectional view showing a lapping machine in which a heater and a heat insulating material layer are arranged on the back surface of a processing board and the back surface of a workpiece as still another configuration example of the planar processing apparatus of the present invention. .

13 is a graph showing a relationship between a voltage applied to a heater on the back of a processing board of the lapping machine of FIG. 12 and an amount of deformation of the processing board.

14A and 14B are diagrams illustrating a configuration example of a conventional typical lapping machine, where FIG. 14A is a top view and FIG. 14B is a cross-sectional view taken along line XX.

FIG. 15 is a schematic sectional view showing a configuration example of a conventional typical chemical mechanical polishing apparatus.

[Explanation of symbols]

 11, 57 Work board 11a Work surface 11t Upper half 11b Lower half 12, 12a, 12b Heater 13, 13a, 13b Heat insulating material layer 14 Workpiece 15 Workpiece holding member 15a Holding face 16, 22 Cavity 18 Cooling water Piping 19 Polishing cloth 20 Rigid block 21 Sealing material 31, 42, 61, 67 Rotary connector 32, 43, 60, 68 Transformer 33, 44, 63, 69 Power supply 34, 38 Rotary joint 35 Polishing head 64 Carrier

Claims (18)

[Claims] 1. A plane processing method for obtaining a desired plane while slidingly contacting a rotating workpiece with a working surface of a rotating processing board, wherein the surface of the working surface of the processing board during the sliding contact. A planar processing method, wherein at least one of a profile, a surface profile of the workpiece, and a surface profile of a workpiece holding member of a polishing head that holds the workpiece is thermally controlled. 2. The method according to claim 1, wherein the control is performed by adjusting an amount of power to a heating unit provided on at least one of the processing board, the back surface of the workpiece, and the polishing head. The planar processing method described. 3. The method according to claim 2, wherein a thick plate body is used as the workpiece, and a surface profile of the thick plate body is controlled from a back surface thereof by using the heating means. . 4. A thin plate body is used as the workpiece, and a surface profile of a workpiece holding member of the polishing head that holds the thin plate body is controlled using the heating means. Item 2. The planar processing method according to Item 2. 5. The method according to claim 4, wherein a semiconductor wafer is used as the thin plate member. 6. The method according to claim 1, wherein cooling by cooling means is used in combination with the control. 7. The workpiece according to claim 1, wherein the workpiece is polished by performing the sliding contact while supplying an abrasive onto the work surface. Plane processing method. 8. The method according to claim 7, wherein the workpiece is chemically and mechanically polished by stretching a polishing cloth on the work surface and performing the sliding contact. . 9. A rotary processing board, and a rotary polishing head for holding a workpiece facing a work surface of the processing board, wherein the workpiece is slidably contacted with the work surface. A planar processing apparatus for obtaining a desired plane, a heating unit for thermally changing a surface profile of the processing board, a heating unit for thermally changing a surface profile of the workpiece, or A planar processing apparatus comprising: at least one of heating means for thermally changing a surface profile of a workpiece holding member of a polishing head that holds the workpiece. 10. The workpiece heating member is a flat heater, and the flat heater is provided on a surface of the processing board opposite to the work surface, a back surface of the workpiece, or a workpiece holding member of the polishing head. The planar processing apparatus according to claim 9, wherein the planar heater is in contact with at least one of the surfaces opposite to the holding surface, and the planar heater is further covered with a heat insulating material layer. 11. The plane processing apparatus according to claim 10, wherein the processing board comprises a joined body of an upper half having the work surface and a lower half contacted with the flat heater. 12. The upper half portion is formed of a set of rigid blocks whose substantially whole area of the work surface is adjacent to each other via an elastic material layer and individually joined to the lower half portion. The planar processing apparatus according to claim 11, wherein: 13. The apparatus according to claim 9, wherein at least one of the processing board, the workpiece, and the polishing head includes a cooling unit in addition to the heating unit. The planar processing apparatus according to the above. 14. An apparatus according to claim 13, wherein said cooling means is a refrigerant circulation system. 15. The flattening apparatus according to claim 14, wherein a cavity for refrigerant circulation is provided as a part of the refrigerant circulation system at a part of a joining surface between the upper half and the lower half. . 16. The apparatus according to claim 13, wherein both the heating means and the cooling means are thermoelectric cooling elements. 17. The apparatus according to claim 9, further comprising an abrasive supply unit for supplying an abrasive onto the work surface. 18. The planar processing apparatus according to claim 17, wherein a polishing cloth is stretched on the work surface to perform chemical mechanical polishing of the workpiece.