JP5087561B2 - Electrostatic chuck - Google Patents

Description

  The present invention relates to an electrostatic chuck used for holding and transporting a wafer or the like of a semiconductor manufacturing apparatus, and more particularly to an electrostatic chuck characterized by the structure of a gas flow path provided on a substrate.

When an electrostatic chuck is used in a semiconductor manufacturing apparatus such as a plasma CVD apparatus, a plasma etching apparatus, an ion implantation apparatus, an ion doping apparatus, or a plasma doping apparatus, it is necessary to hold and fix an object to be adsorbed such as a wafer at the same time. is there.
This is because, in plasma processing, high-energy ions collide with the object to be adsorbed, and a part of the high-frequency power for plasma generation is consumed by the object to be adsorbed, so Because it reaches.
The cooling temperature of the adsorbent is required to be kept at 100 ° C. or lower from the necessity of preventing dust from being generated from the organic resist material used for patterning on the adsorbent.
Since the processing chamber for processing the object to be adsorbed with plasma is maintained in a vacuum, the reason for heating the object to be adsorbed is that heat is conducted from the electrostatic chuck in contact with the object to be adsorbed to the object to be adsorbed. In some cases, convection of hot gas in the processing chamber may occur.
Therefore, conversely, it can be said that the object to be adsorbed can be cooled to 100 ° C. or less by contact between the object to be adsorbed and the electrostatic chuck or by convection of the cooling gas. However, since an object to be attracted such as a wafer is bent or warped, the contact area with the electrostatic chuck is small. In particular, when ceramic is used for the electrostatic chuck, it is empirically known that the effective contact area between the ceramic and the object to be adsorbed is 1% or less of the adsorbing object mounting surface. .
Therefore, under high temperature conditions where power of several hundred watts or more is consumed by the adsorbent, a method of cooling the adsorbent using a cooling gas has become the mainstream.
As a cooling gas flow path structure of an electrostatic chuck, a cooling gas flow path is usually provided on the surface of a lowermost metal substrate, and a plurality of ventilation holes are formed on the substrate. A structure is adopted in which the air holes are opened in the surface of the dielectric layer while being formed in the body layer so as to communicate with the gas flow path of the substrate. With this structure, the cooling gas is caused to flow through the gas flow path of the substrate at a pressure in the range of 10 Torr to 30 Torr, and is injected from the vent toward the adsorbent to cool the adsorbent from below.
However, in an electrostatic chuck that is placed in an atmosphere of high-temperature plasma and to which high-frequency power is applied, glow discharge and arc discharge are generated in the air holes and gas flow paths, and countermeasures against them are problematic. In particular, when the vent hole extends vertically and the lower metal substrate is exposed to the outside through the vent hole, there is a high possibility that a discharge will occur between the metal substrate and the adsorbent.
Such discharge can be predicted by multiplying the pressure of the cooling gas by the distance between the adsorbent and the substrate according to Paschen's law. However, as long as a cooling gas having a pressure of 10 Torr to 30 Torr is used, it is impossible to prevent such discharge.
Therefore, various electrostatic chucks having a discharge preventing function have been proposed.
15 is a schematic cross-sectional view of an electrostatic chuck according to a first conventional example, FIG. 16 is a schematic cross-sectional view of an electrostatic chuck according to a second conventional example, and FIG. 17 is a third conventional example. It is a schematic sectional drawing of the electrostatic chuck which concerns on an example. In these sectional views, the adsorption electrode is omitted.

As shown in FIG. 15, the electrostatic chuck 100 according to the first conventional example communicates the vent hole 121 formed in the dielectric layer 120 to the gas flow path 111 of the substrate 110 and folds the vent hole 121. It is formed in a bent shape.
Accordingly, the substrate 110 is made invisible from the opening 121a of the vent hole 121 to prevent discharge between the substrate 110 and the adsorbed member W indicated by a two-dot chain line (for example, Patent Document 1). reference).
Further, as shown in FIG. 16, in the electrostatic chuck 200 according to the second conventional example, the gas flow path 211 in the substrate 210 has a cylindrical shape, and the ceramic tubular body 212 has this gas flow path. The entire inner surface of the gas flow path 211 is covered with the cylindrical body 212.
As a result, the ceramic cylindrical body 212 as an insulator is interposed between the substrate W and the adsorbed body W on the dielectric layer 220 having the air holes 221. This prevents discharge between the adsorbent W and the substrate 200 (see, for example, Patent Document 2).
Further, as shown in FIG. 17, in the electrostatic chuck 300 according to the third conventional example, the gas flow path 311 is formed in a ring shape on the surface of the substrate 310, and the ring-shaped insert 312 having a plurality of holes 312a is formed. The gas channel 311 is fitted. A ceramic porous body 313 is inserted into the hole 312 a of the insert 312.
Thereby, the ceramic porous body 313 as an insulator is interposed between the adherend W on the dielectric layer 320 and the substrate 310, and the porous body 313 is attached to the adherend W and the substrate 310. (See, for example, Patent Document 3).

JP 2004006505 A JP 2005-268654 A Japanese Patent Laid-Open No. 10-050813

However, the conventional electrostatic chuck described above has the following problems.
First, although the electrostatic chuck 100 according to the first conventional example shown in FIG. 15 has a structure in which the substrate 110 is not visible from the opening of the vent hole, the discharge prevention is not sufficient, and an abnormality occurs at the opening portion of the vent hole. There was a risk of discharge.
On the other hand, in the electrostatic chucks 200 and 300 according to the second and third conventional examples shown in FIGS. 16 and 17, the insulators such as the cylindrical body 212 and the porous body 313 are replaced with the object to be adsorbed W. And the gas flow paths 211 and 311 of the substrates 210 and 310, the effect is sufficiently exhibited in terms of preventing discharge.
However, the electrostatic chucks 200 and 300 according to the second and third conventional examples have the following problems.

FIG. 18 is a perspective view for explaining the problems of the electrostatic chuck according to the second conventional example, and FIG. 19 is a perspective view for explaining the problems of the electrostatic chuck according to the third conventional example. FIG.
In recent years, there has been a call for resource saving and the realization of environmentally friendly semiconductor manufacturing, and resource saving through reuse of electrostatic chucks has become an important issue.
That is, it is necessary to save resources by reusing a large quantity of electrostatic chucks that have become unusable due to discharge or the like and are left on site. Such reuse is performed by scraping off the adsorption electrode or dielectric layer on the substrate and regenerating a new adsorption electrode or dielectric layer on the substrate.
Accordingly, in the electrostatic chuck 200 of the second conventional example, as shown in FIG. 18, the dielectric layer 220 and the attracting electrode (not shown) are scraped off from the substrate 210, and the new dielectric layer 220 and the attracting electrode are replaced with the substrate 210. By recycling the substrate upward, the substrate 210 can be reused.
However, since one gas flow path 211 of the substrate 210 and one vent hole 221 of the dielectric layer 220 are in communication with each other, the position of each gas flow path 211 is determined when the dielectric layer 220 or the adsorption electrode is regenerated. Each vent hole 221 must be drilled in the dielectric layer 220 so as to match exactly, that is, to match the points, and the drilling operation is very difficult.
For this reason, when the electrostatic chuck 200 is reused, a highly accurate and difficult alignment operation and drilling operation of the air holes 221 are forced every time the dielectric layer 220 and the suction electrode are regenerated. As a result, the reproduction time becomes longer and the work efficiency is poor. Therefore, the electrostatic chuck 200 according to the second conventional example is structurally unsuitable for reuse and lacks qualification as a product that can meet the problem of resource saving by reuse.
On the other hand, also in the electrostatic chuck 300 in the third conventional example, the substrate 310 can be reused by scraping the dielectric layer 320 and the attracting electrode from the substrate 310 as shown in FIG.
However, since the electrostatic chuck 300 has a structure in which one hole 312a of the insert 312 and one ventilation hole 321 of the dielectric layer 320 are communicated with each other, like the electrostatic chuck 200, the dielectric layer 320 and the like. At the time of reproduction, each of the vent holes 321 must be drilled in the dielectric layer 320 so as to exactly coincide with the position of each hole 312a.
For this reason, as with the electrostatic chuck 200 described above, a highly accurate positioning operation and drilling operation of the vent holes 321 are forced, and the electrostatic chuck 200 according to the third conventional example is also structurally It is not suitable for reuse and lacks eligibility as a product that can meet the problem of resource saving through reuse.

  The present invention has been made to solve the above-described problems, and can provide an electrostatic chuck having a structure suitable not only for reuse but also for preventing abnormal discharge generated in a dielectric layer or a substrate. Objective.

In order to solve the above-mentioned problems, the invention of claim 1 is directed to a substrate having a ring-shaped, curved or straight gas flow path recessed on the surface, and a surface of the substrate so as to airtightly cover the gas flow path. An electrostatic chuck comprising a dielectric layer having a vent hole formed and having a lower opening located in the gas flow path and an upper opening located on the surface, and an adsorption electrode formed in the dielectric layer. In plan view, a support member having the same shape and width as the gas flow path is fitted into the gas flow path, and is a band having a shape corresponding to the shape of the support member in plan view, and is larger than the diameter of the vent hole. A porous insulator having a wide upper surface is brought into contact with the lower opening of the vent hole with the support member in a state where the upper surface of the insulator is exposed, and at least a part of the lower portion of the insulator is in contact with the gas flow. supported so as to be exposed in the road, and the support member, the plane A top wall portion having the same shape and width as the gas flow path, and a ceiling wall section provided below the top wall section along the length direction of the top wall section and hanging down to the bottom surface of the gas flow path And a long groove having a predetermined depth that opens upward on the upper surface of the top wall portion over the entire length of the top wall portion, and communicates with the long groove. A plurality of opening grooves that open in the gas flow path are provided at predetermined intervals on the lower surface of the top wall portion, and an insulator is filled into the long groove to expose the upper surface of the insulator, and a plurality of lower portions of the insulator are provided. It is set as the structure exposed to the gas flow path side through this opening groove | channel.
With this configuration, the object to be adsorbed is placed on the surface of the dielectric layer, and a voltage is applied to the adsorption electrode so that the object to be adsorbed is caused by the electrostatic force between the dielectric layer and the object to be adsorbed. Adsorbed and fixed to the surface. In this state, when the cooling gas is passed through the gas flow path, the cooling gas enters the porous insulator from the exposed lower portion of the insulator supported by the support member, and the dielectric layer from the upper surface and the lower opening. Flows into the air vent. Then, the cooling gas flows out from the upper opening through the vent hole, and the adsorbent is cooled from the lower side by the cooling gas. In a plasma atmosphere, a high-frequency voltage for generating plasma is applied between the adsorbent and the substrate, and abnormal discharge may occur. However, the electrostatic chuck of the present invention has a configuration in which the upper surface of the insulator is in contact with the lower opening of the vent hole, and the insulator is interposed between the attracted member to which a voltage is applied and the substrate. This insulator prevents abnormal discharge.
Further, when the electrostatic chuck becomes unusable as a result of long-term use, the substrate can be reused by scraping the dielectric layer and the attracting electrode from the substrate. Specifically, the dielectric layer is formed on the substrate, the adsorption electrode is formed in the dielectric layer, the air holes are formed in the dielectric layer, and communicated with the gas flow path through the insulator of the substrate. Do work. At this time, since the insulator is a band, it is easy to align the air holes on the band. Moreover, since the insulator has an upper surface that is wider than the diameter of the vent hole, the vent hole is positioned on the upper surface of the insulator even if the position of the vent hole is slightly shifted in the width direction of the insulator. That is, aligning the air hole with the insulator is substantially the same as placing the point on the surface, so that the air hole can be aligned with the insulator very easily. As described above, when the vent hole and the insulator are aligned, the lower opening of the vent hole comes into contact with the upper surface of the insulator supported by the support member, and the vent hole is connected to the gas flow path via the insulator. Communicate. In this way, the dielectric layer and the adsorption electrode can be easily reproduced on the substrate.
Specifically, the cooling gas in the gas flow path reaches the lower part of the insulator from the opening groove on the lower surface of the top wall part, flows into the insulator from the lower part, and opens upward in the long groove of the top wall part. It flows out from the upper surface of the insulator into the ventilation hole of the dielectric layer. Then, the cooling gas flows out from the upper opening of the vent hole. When the dielectric layer is formed on the substrate, the vent hole is aligned with the upper surface of the insulator exposed from the opening on the top wall side, so that the vent hole is accurately aligned with the insulator. It can be carried out.

According to a second aspect of the present invention, in the electrostatic chuck according to the first aspect, the porous insulator is a porous ceramic.
With this configuration, the cooling gas in the gas flow channel flows into the ventilation hole of the dielectric layer through the porous ceramics, and flows out from the upper opening of the ventilation hole. Moreover, the ceramic exhibits a higher effect of preventing abnormal discharge.

  As described above in detail, according to the electrostatic chuck of the present invention, not only can abnormal discharge be prevented, but also when the dielectric layer and the suction electrode are formed on the substrate, the position of the vent hole relative to the insulator is not limited. Since the alignment can be easily performed, the regeneration time of the dielectric layer and the adsorption electrode is short, and the work efficiency is very good. In other words, the electrostatic chuck of the present invention is structurally suitable for reuse, and has an eligibility as a product that can meet the problem of resource saving through reuse.

  In particular, according to the invention of claim 2, a higher effect of preventing abnormal discharge can be expected.

1 is an exploded perspective view showing an electrostatic chuck according to an embodiment of the present invention. It is an external view of the electrostatic chuck of FIG. It is arrow AA sectional drawing of FIG. It is a top view which shows a board | substrate and a supporting member. It is arrow BB sectional drawing of FIG. FIG. 5 is a cross-sectional view taken along the line CC in FIG. 4. It is a partial expansion perspective view which fractures | ruptures and shows a part of support member. FIG. 5 is a development view taken along the line DD in FIG. 4. It is a top view which shows an adsorption electrode. It is a top view which shows a dielectric material layer. It is the schematic for demonstrating the adsorption | suction effect | action of an electrostatic chuck. It is a partial expanded sectional view for demonstrating the cooling effect | action and abnormal discharge prevention effect | action of an electrostatic chuck. It is a fragmentary top view for demonstrating the positioning method of a ventilation hole. It is sectional drawing which shows the modification of the combined structure of a supporting member and an insulator. It is a schematic sectional drawing of the electrostatic chuck which concerns on a 1st prior art example. It is a schematic sectional drawing of the electrostatic chuck which concerns on a 2nd prior art example. It is a schematic sectional drawing of the electrostatic chuck which concerns on a 3rd prior art example. It is a perspective view for demonstrating the problem of the electrostatic chuck which concerns on a 2nd prior art example. It is a perspective view for demonstrating the problem of the electrostatic chuck which concerns on a 3rd prior art example.

The best mode of the present invention will be described below with reference to the drawings.
Example 1

1 is an exploded perspective view showing an electrostatic chuck according to one embodiment of the present invention, FIG. 2 is an external view of the electrostatic chuck of FIG. 1, and FIG. It is A sectional drawing.
As shown in FIG. 1, the electrostatic chuck 1 of this embodiment is an electrostatic chuck for a 200 mm wafer, and includes a substrate 2, an adsorption electrode 3, and a dielectric layer 4.

The substrate 2 located at the bottom in FIG. 1 is a disc body made of aluminum. In this embodiment, the substrate 2 has a diameter of 200 mm and a thickness of 10 mm.
On the surface of the substrate 2, ring-shaped gas flow paths 21 and 22 are recessed. In this embodiment, the width and depth of the gas flow paths 21 and 22 are set to 5 mm and 3.5 mm, respectively. The outer gas flow path 21 was disposed at a position 20 mm from the outer edge of the substrate 2, and the inner gas flow path 22 was disposed at a position 20 mm from the center of the substrate 2.
Support members 5-1 and 5-2 that support the insulator 6 are fitted in the gas flow paths 21 and 22, respectively.
The cooling gas is supplied into the gas flow paths 21 and 22 from a supply port (not shown), and cooling water for cooling the substrate 2 is flown into the substrate 2 (not shown). A passage is provided.

4 is a plan view showing the substrate 2 and the support members 5-1 and 5-2, FIG. 5 is a cross-sectional view taken along the line BB in FIG. 4, and FIG. 6 is a view taken in the direction of the arrow in FIG. FIG. 7 is a partially enlarged perspective view in which a part of the support members 5-1 and 5-2 is cut away, and FIG. 8 is a development view taken along the line DD in FIG. It is.
As shown in FIGS. 4 and 5, the support member 5-1 (5-2) is made of aluminum, and has a ceiling wall 50 having the same shape and width as the gas flow path 21 (22). It consists of the standing wall part 51 provided in the lower side of the wall part 50, and the cross section comprises T shape.
Specifically, as shown in FIG. 5, the top wall 50 is located in the upper opening of the gas flow path 21 (22). And the standing wall part 51 hangs down from the lower side of the top wall part 50 to the bottom face 21a (22a) of the gas flow path 21 (22), and supports the top wall part 50 in the gas flow path 21 (22). . Thereby, the standing wall 51 divides the gas flow path 21 (22) on both sides of the standing wall 51. As shown in FIGS. 7 and 8, the standing wall portion 51 is provided over the entire length of the top wall portion 50 in the length direction. And the notch part 51a is provided in the predetermined location of the standing wall part 51, and the inside of the gas flow path 21 (22) divided by the standing wall part 51 is connected by this notch part 51a. Thereby, cooling gas flows into the other side from the one side of the gas flow path 21 (22). In this embodiment, the thickness of the top wall portion 50 and the standing wall portion 51 is set to about 1 mm.

A long groove 8 opened upward is provided on the top surface of the top wall 50. As shown in FIGS. 4 and 5, the long groove 8 is formed over the entire length of the top wall 50 in a state of being arranged at the center of the top wall 50. In this example, the width d1 and the depth d2 of the long groove 8 were set to 0.8 mm and 0.5 mm, respectively.
An opening groove 81 is provided on the lower surface of the top wall portion 50 as shown in FIG. The opening groove 81 is a semicircular groove having a radius of about 1 mm that communicates with the long groove 8 and opens into the gas flow path 21 (22). As shown by the broken line in FIG. 4, a plurality of such opening grooves 81 are provided below the top wall portion 50 of the support member 5-1 (5-2), and are arranged at intervals of 1 cm, for example.

As shown in FIG. 6, the insulator 6 is a porous ceramic and is filled in the long groove 8 of the support member 5-1 (5-2). As a result, the upper surface 61 of the insulator 6 is exposed upward, and the lower portion 62 of the insulator 6 is exposed toward the gas flow path 21 (22) through each opening groove 81.
The filling of the insulator 6 into the long groove 8 can be performed by thermal spraying of ceramic particles or cutting of porous ceramics. In this embodiment, thermal spraying was used.
Specifically, alumina particles having a purity of 99.9% or higher were sprayed from above the top wall portion 50 into the long groove 8 using a spray gun (not shown). Thermal spraying was performed in two stages. In the first stage, coarse-grained alumina was used and sprayed to a predetermined depth of the long groove 8 to ensure an approximate thickness of the insulator 6. In the second stage, fine-grained alumina was sprayed from above the alumina layer in the long groove 8 to a thickness of, for example, 10 μm to 50 μm. Thus, the porosity of the insulator 6 in the long groove 8 was high in the lower layer (10% to 30%) and low in the upper layer (10% or less).

The adsorption electrode 3 shown in FIG. 1 is an electrode for inducing charge in the dielectric layer 4 and is a conductor pattern formed inside the adsorption electrode 3. In this example, the adsorption electrode 3 was formed by spraying a metal having high heat resistance and corrosion resistance such as tungsten, tantalum, and molybdenum, or by patterning the paste-like metal by exposure and development. In this example, the thickness of the adsorption electrode 3 was set to 5 μm to 40 μm.
FIG. 9 is a plan view showing the adsorption electrode 3.
As shown in FIG. 9, the adsorption electrode 3 of this embodiment is a bipolar adsorption electrode. That is, the adsorption electrode 3 was configured by alternately arranging the concentric first electrode adsorption electrode patterns 31 and the second concentric second electrode adsorption electrode patterns 32. The DC power supply 400 and the switch 401 were connected to the first and second electrode attracting electrode patterns 31 and 32, respectively. Further, the gap d3 between the first and second electrode attracting electrode patterns 31, 32 is set to be larger than the width d1 of the upper surface 61 of the insulator 6, and the upper surface 61 of the insulator 6 is placed in the gap d3. Included.

  The dielectric layer 4 shown in FIG. 1 is a layer formed by thermal spraying ceramics on the substrate 2, and is formed on the substrate 2 so as to cover the adsorption electrode 3 as shown in FIG. 3. Specifically, the dielectric layer 4 is alumina having a purity of 99.9% or more, and both the lower layer thickness and the upper layer thickness of the adsorption electrode 3 are set to 300 μm. However, these layer thicknesses can be set within a range of 150 μm to 500 μm, and are adjusted according to the specification conditions. As shown in FIG. 2, such a dielectric layer 4 hermetically covers the entire substrate 2 having the gas flow paths 21 and 22, and a plurality of hole-shaped ventilation holes 41 are formed in the dielectric layer 4. Has been drilled.

FIG. 10 is a plan view showing the dielectric layer 4.
As shown in FIG. 10, the plurality of vent holes 41 are formed by ultrasonic processing so as to coincide with the upper surface 61 of the insulator 6 indicated by a two-dot chain line. That is, as shown in FIG. 5, each air hole 41 is formed such that the lower opening 41 a contacts the exposed upper surface 61 of the insulator 6 and the upper opening 41 b is positioned on the surface 4 a of the dielectric layer 4. The dielectric layer 4 is perforated. In this embodiment, the diameter d4 of the vent hole 41 is set to 0.2 mm, and the upper surface 61 having a width of 0.8 mm d1 is set to be sufficiently wider than the diameter d4 of the vent hole 41.

Next, operations and effects of the electrostatic chuck 1 of this embodiment will be described.
FIG. 11 is a schematic view for explaining the attracting action of the electrostatic chuck 1, and FIG. 12 is a partially enlarged sectional view for explaining the cooling action and the abnormal discharge preventing action of the electrostatic chuck 1.
As shown in FIG. 11, when the wafer W, which is an object to be adsorbed, is placed on the dielectric layer 4, the wafer W comes into contact with the surface 4a. In this state, when the switch 401 is closed and the DC power source 400 is applied to the first and second electrode adsorption electrode patterns 31 and 32 of the adsorption electrode 3, the positive charge is applied to the first electrode adsorption electrode pattern 31 of the adsorption electrode 3. As a result, the negative charges are collected right above the second electrode adsorption electrode pattern 32. The wafer W is attracted to the surface 4a of the dielectric layer 4 and fixed by the electrostatic force of these charges and the charge induced on the wafer W.

In this state, as shown in FIG. 12, when the cooling gas G is passed through the gas flow path 21 (22), the cooling gas G enters the porous insulator 6 from the opening groove 81 through the lower portion 62. Further, the cooling gas G in the gas channel 21c (22c) on the left side of the drawing divided by the standing wall portion 51 of the support member 5-1 (5-2) is notched 51a (see FIG. 7 and FIG. 7 for details). 8) and enters the gas channel 21b (22b) on the right side of the figure, and enters the insulator 6 from the lower part 62 exposed in the gas channel 21b (22b). In this way, the cooling gas G efficiently flows through the gas flow path 21 (22) through the notch 51a, so that the conductance of the cooling gas G is high.
The cooling gas G that has entered the insulator 6 as described above rises in the insulator 6 and flows into the vent hole 41 from the lower opening 41 a that is in contact with the upper surface 61. Thereafter, the cooling gas G flows out from the upper opening 41b of the vent hole 41 to cool the wafer W from below.

When the electrostatic chuck 1 is placed in a plasma atmosphere, a high frequency voltage for generating plasma is applied between the aluminum bottom surface 21a (22a) of the gas flow path 21 (22) and the wafer W, Abnormal discharge may occur.
However, in the electrostatic chuck 1 of this embodiment, the insulator 6 is interposed between the wafer W and the gas flow path 21 (22) in a state where the upper surface 61 is in contact with and closed by the lower opening 41a of the vent hole 41. Since it is interposed, abnormal discharge is prevented by the insulating effect of the insulator 6 made of alumina.

  When the electrostatic chuck 1 of this embodiment is reused, first, the attracting electrode 3 and the dielectric layer 4 shown in FIG. 1 are scraped from the substrate 2 to form the dielectric layer 4 on the substrate 2. At the same time, the adsorption electrode 3 is formed in the dielectric layer 4. A plurality of vent holes 41 are formed in the dielectric layer 4, and the gas flow paths 21 (22) are formed through the insulator 6 supported by the support members 5-1 (5-2) of the substrate 2. ) To communicate.

FIG. 13 is a partial plan view for explaining a method of positioning the vent hole 41.
In the electrostatic chucks of the second and third conventional examples, as shown in FIG. 13A, the position P of the vent hole 41 is set to a gas channel 211 or a porous body 313 having a small circular shape in plan view. It is necessary to make a vent hole 41 at this position. That is, it is necessary to accurately determine the r direction and the θ direction of the drilling position P, which is a difficult task such that the points are substantially aligned on the points.
On the other hand, in the electrostatic chuck 1 of this embodiment, as shown in FIG. 13 (b), the drilling position P of the vent hole 41 is adjusted to any position on the belt-like upper surface 61, What is necessary is just to drill the ventilation hole 41 in the position. That is, if only the r direction of the drilling position P is accurately determined and drilled, the vent hole 41 is drilled on the upper surface 61 of the insulator 6. Moreover, since the width d1 of the upper surface 61 is set to be larger than the diameter d4 of the vent hole 41, the vent hole 41 can be reliably drilled on the upper surface 61 even if the drilling position P is slightly shifted in the r direction. Can do. Therefore, in the electrostatic chuck 1 of this embodiment, the drilling operation of the vent hole 41 can be achieved by an extremely easy operation of aligning the points on the surface.
Thus, by aligning the vent hole 41 on the upper surface 61 of the insulator 6, the lower opening 41 a of the vent hole 41 coincides with the upper surface 61, and the vent hole 41 flows through the insulator 6 through the gas flow. It communicates with the road 21 (22). Thus, the dielectric layer 4 and the attracting electrode 3 are formed on the substrate 2, and the electrostatic chuck 1 can be reused.

  As described above, according to the electrostatic chuck 1 of this embodiment, not only abnormal discharge can be prevented, but also when the dielectric layer 4 and the suction electrode 3 are formed on the substrate 2, the insulation of the air holes 41 is achieved. Since the positioning with respect to the body 6 is easy, the reproduction work time is short and the reproduction can be performed efficiently. That is, it can be said that the electrostatic chuck 1 is structurally suitable for reuse, and has a qualification as a product that can meet the problem of resource saving by reuse.

In addition, this invention is not limited to the said Example, A various deformation | transformation and change are possible within the range of the summary of invention.
For example, in the above embodiment, as shown in FIGS. 5 and 6, the long groove 8 is provided in the support member 5-1 (5-2) having a T-shaped cross section, and the insulator 6 is filled in the long groove 8. However, the support member may be any member as long as it is set in the same shape and width as the gas flow channel in a plan view and can be fitted in the gas flow channel. It suffices that the lower opening is abutted and at least a part of the lower part is exposed in the gas flow path. Therefore, as shown in FIG. 14A, an electrostatic chuck having a structure in which the standing wall portion 51 of the support member 5-1 (5-2) occupies the left portion of the gas flow path 21 (22), As shown in FIG. 14 (b), the standing wall portion 51 of the support member 5-1 (5-2) is shifted to the left side, and the entire support member 5-1 (5-2) is L-shaped. An electrostatic chuck is also included in the scope of the present invention.
In the above embodiment, an example in which the double gas flow paths 21 and 22 are applied as the gas flow paths has been shown. However, the number of the gas flow paths is arbitrary, and the single or triple gas flow paths are used. It may be applied. The gas flow path is not limited to a ring shape, and a curved or straight gas flow path can also be applied.

  DESCRIPTION OF SYMBOLS 1 ... Electrostatic chuck, 2 ... Board | substrate, 3 ... Adsorption electrode, 4 ... Dielectric layer, 4a ... Surface, 5-1, 5-2 ... Supporting member, 6 ... Insulator, 61 ... Upper surface, 62 ... Lower part, 8 ... long groove, 21, 22 ... gas flow path, 21a, 22a ... bottom, 31 ... first electrode adsorption electrode pattern, 32 ... second electrode adsorption electrode pattern, 41 ... vent hole, 41a ... lower opening, 41b ... upper opening, DESCRIPTION OF SYMBOLS 50 ... Top wall part, 51 ... Standing wall part, 51a ... Notch part, 81 ... Opening groove, 400 ... DC power supply, 401 ... Switch, G ... Cooling gas, W ... Wafer.

Claims (2)

A substrate in which a ring-shaped, curved or straight gas flow path is recessed on the surface;
A dielectric layer formed on the surface of the substrate so as to airtightly cover the gas flow path and having a vent hole in which the lower opening is located in the gas flow path and the upper opening is located on the surface;
An electrostatic chuck comprising an adsorption electrode formed in the dielectric layer,
In plan view, a support member having the same shape and width as the gas channel is fitted into the gas channel,
In the plan view, a porous insulator having a shape corresponding to the shape of the support member and having an upper surface wider than the diameter of the air hole is exposed to the upper surface of the insulator by the support member. In such a state, it is supported so as to contact the lower opening of the vent hole and at least a part of the lower portion of the insulator is exposed in the gas flow path ,
And the said support member is provided along the length direction of a ceiling wall part on the lower side of this ceiling wall part and the ceiling wall part of the same shape and width as the said gas channel in planar view, and the said gas channel It is composed of a standing wall part that hangs down to the bottom of the wall and supports the top wall part in the gas flow path,
On the upper surface of the top wall portion, a long groove having a predetermined depth that opens upward is provided over the entire length of the top wall portion, and a plurality of opening grooves that communicate with the long groove and open in the gas flow path are provided. Provided at a predetermined interval on the lower surface of the top wall,
Filling the insulator into the long groove, exposing the upper surface of the insulator and exposing the lower portion of the insulator to the gas flow path side through the plurality of opening grooves,
An electrostatic chuck characterized by that. The electrostatic chuck according to claim 1,
The porous insulator is a porous ceramic,
An electrostatic chuck characterized by that.

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