JP2020167220A - Sample holding tool - Google Patents

Abstract

To provide a sample holding tool that is hardly affected by an external environment, and can quickly achieve and maintain a change in sample temperature and a uniform temperature distribution in a sample.SOLUTION: A sample holding tool 10 of the present disclosure comprises: a plate-like ceramic substrate 1 that has a top face 1a on which a sample can be placed; a base plate 2 that supports the ceramic substrate 1 from below; a coolant channel R that is formed inside the base plate 2; and a heat insulating material 3 that is disposed below the coolant channel R.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a sample holder for holding a sample such as a semiconductor wafer, which is used in a manufacturing process of a semiconductor integrated circuit, a manufacturing process of a liquid crystal display device, or the like.

An electrostatic chuck is known as a sample holder used in a semiconductor manufacturing apparatus or the like. The electrostatic chuck is a sample holding member (also referred to as a substrate or a ceramic body) having a sample holding surface for placing and adsorbing and holding a sample (also referred to as an object or a work) such as a wafer, and this sample holding. It is configured by joining a metal support member (also called a base plate) that supports the member from below with a bonding material such as an adhesive.

Since the sample holder undergoes a plurality of treatment steps with the sample placed or held on the sample holding surface, it is necessary to change and maintain the sample at a temperature suitable for each treatment. Therefore, it is provided with a mechanism for making the temperature distribution of the sample placed on the sample holding surface uniform. The uniform temperature distribution of the sample may be referred to as heat equalization, and the device performance for maintaining or controlling the uniform temperature distribution of the sample may be referred to as heat equalization.

For example, the sample holder includes a heating device such as a heater for heating the sample through the sample holding member and raising the temperature in the upper sample holding member in order to raise the sample to a target temperature. .. Further, in the lower support member, a flow path and a circulation system for circulating a fluid (heat medium) such as a liquid as a refrigerant for cooling or lowering the temperature of the sample via the support member and the sample holding member are provided. A cooling device is provided (see Patent Document 1).

JP-A-2017-143182

By the way, the environment on the lower side of the sample holder (bottom side of the support member) with respect to the space on the upper side (sample holding surface side) where the environment such as atmospheric temperature is controlled for processing or processing the sample. Is not so strict in temperature control.

Therefore, due to the influence of the environmental temperature on the lower side of the sample holder, the temperature distribution of the sample held on the sample holding surface may vary, or heating (increasing) or cooling (lowering) by the above-mentioned heating device or cooling device may occur. It has been found that efficiency and speed of reaction response may decrease.

An object of the present disclosure is to provide a sample holder that is not easily affected by the external environment and can quickly achieve and maintain a change in sample temperature and a uniform temperature distribution in a sample.

The sample holder of the present disclosure includes a flat plate-shaped sample holding member having an upper surface on which a sample can be placed, a support member that supports the sample holding member from below, and a refrigerant formed inside the support member. It includes a flow path and a heat insulating material disposed below the flow path of the refrigerant.

According to the present disclosure, the sample held on the sample holding surface is suppressed from being affected by heat or temperature from the external environment below the sample holding tool. Therefore, the sample holder of the present disclosure can quickly achieve and maintain a change in the sample temperature and a uniform temperature distribution in the sample.

It is an exploded perspective view of the sample holder of an embodiment. It is a perspective view after assembling the sample holder of an embodiment. It is sectional drawing which shows the arrangement of the main part structure of the sample holder of 1st Embodiment. It is sectional drawing which shows the arrangement of the main part structure of the sample holder of 2nd Embodiment. It is sectional drawing which shows the arrangement of the main part structure of the sample holder of the 3rd Embodiment. It is sectional drawing which shows the arrangement of the main part structure of the sample holder of 4th Embodiment. It is sectional drawing which shows the arrangement of the main part structure of the sample holder of 5th Embodiment. It is sectional drawing which shows the arrangement of the main part composition of the sample holder of 6th Embodiment. (A) is a cross-sectional view of the sample holder of the seventh embodiment, (b) is an enlarged view of part P of (a), and (c) shows a modified example of (b). (A) is a cross-sectional view of the sample holder of the eighth embodiment, (b) is an enlarged view of the Q part of (a), and (c) shows a modified example of (b).

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
The configuration of the sample holder, which is not described in each drawing, for example, the gas flow path through which a gas such as helium flows, the gas fumarole, the electrical wiring, and the mechanism for supplying the refrigerant to the sample holder are described. The illustration is omitted.

The sample holders 10, 20, 30, 40, 50, 60, 70, 80 of the first to eighth embodiments described in the embodiment are arranged inside the ceramic substrate 1 in the manufacturing process of the semiconductor integrated circuit. Due to the electrostatic force generated by applying an electric current between the semicircular electrodes E1 and E2, a sample (commonly known as a work: not shown) such as a semiconductor wafer placed on the upper surface 1a of the substrate, which is a sample holding surface, is moved. An electrostatic chuck that electrostatically attracts and fixes its position on the sample holding surface.

The sample holders of each embodiment have a common basic configuration. As shown in FIG. 1 which is an exploded perspective view of the sample holder 10 of the first embodiment and FIG. 2 which is a perspective view after assembly thereof, each sample holder is insulated from the upper side. A disk-shaped support made of metal (base plate 2) is joined to the lower side of a disk-shaped substrate (ceramic substrate 1) made of a body by using an adhesive or the like described later as a bonding material 4. ing. The ceramic substrate 1 is an example of the sample holding member of the present disclosure, and the base plate 2 is an example of the supporting member of the present disclosure.

The refrigerant flow path (hereinafter, refrigerant flow path R) formed inside the base plate 2 and its introduction port (inlet) and outlet port (outlet), which are indicated by hidden lines (dotted lines), have typical shapes. Is simplified and drawn. For example, in the embodiment, it is illustrated as a plurality of concentric flow paths, but the arrangement / arrangement thereof is not limited to this, and may be arranged in a meandering shape or in a radial pattern. Further, the inlet and the outlet may also be provided at other positions according to the shape and arrangement of the flow path.

As shown in the first embodiment of FIG. 3, the configuration common to the sample holders of each embodiment is the inside of the ceramic substrate 1 having the sample holding surface (base upper surface 1a) and the base plate 2 which is the support member. In the sample holder 10 including the refrigerant flow path R formed in the above, a heat insulating material 3 for forming a heat insulating layer is provided at a position below or below the refrigerant flow path R.

The detailed configuration of the sample holder will be described with reference to the sample holder 10 (FIG. 3). The same configurations as those of the sample holders 10 with respect to the sample holders 20 to 80 described later are designated by the same reference numerals, and detailed description thereof will be omitted.

The ceramic substrate 1 of the sample holder 10 has a disk shape as a whole, and the upper surface 1a of the substrate, which is the main surface, serves as the sample holding surface. The constituent material of the ceramic substrate 1 (sample holding member) can be, for example, alumina, aluminum nitride, silicon nitride, yttria, or the like.

The ceramic substrate 1 is provided with the above-mentioned electrodes E1 and E2 for electrostatic adsorption inside. Further, the ceramic substrate 1 is provided with a heating device such as a heater H for heating and raising the temperature of the sample placed on the upper surface 1a of the substrate.

The ceramic substrate 1 is a plate-shaped member, but the outer shape is not limited, and the ceramic substrate 1 may have a disk shape as in the example, a square plate shape, a polygonal shape, or the like.

The ceramic substrate 1 and the base plate 2 described later are joined by using a joining material 4. As the bonding material 4, an adhesive made of silicone resin, fluororesin, or the like can be used.

The base plate 2 is a member that supports and supports the ceramic substrate 1 from below. As a material constituting the base plate 2, a metal such as aluminum can be used. The outer shape of the base plate 2 is not particularly limited, and the outer shape corresponds to the shape of the ceramic substrate 1 described above, such as a circular shape, a quadrangular shape, and a polygonal shape.

The base plate 2 is provided with one (one) or more groove-shaped refrigerant flow paths R inside, in this example, in the thickness (height) direction of the base plate 2 and near the center in the vertical direction shown in the drawing. As described above, since the refrigerant flow paths R are arranged concentrically, meanderingly, radially, or the like in the horizontal direction (plan view), the refrigerant flow in FIGS. 3 to 8 showing the vertical cross section. The number of roads R shown does not necessarily match the actual number of groove shapes.

Further, the base plate 2 in the embodiment has a plurality of blocks in the vertical direction at least at the upper end position or the lower end position of the flow path for the groove shape processing (engraving formation, mold molding, etc.) of the refrigerant flow path R described above. It may be divided into.

In the embodiment, among the blocks of the divisible base plate 2, the block located on the upper side of the ceramic substrate 1 is called the first support 2A, and the lower block located on the outer side of the sample holder is called the second support. It is called the support 2B. There is no particular difference between the first support 2A and the second support 2B in properties other than the shape, including the material. Therefore, as shown in FIGS. 4 and 6 to 8 described later, when they can be separated and divided, but there is no particular need to separate them in terms of configuration and they can be regarded as one, the above-mentioned individual names are used. It may not be used, and the same hatching may be continuously applied in the drawings to refer to it as one member name (base plate 2). Dotted lines in the cross-sectional view indicate divisible positions in the integrated base plate 2.

Further, the first to sixth embodiments are examples in which the upper first support 2A and the lower second support 2B use the base plate 2 having the same outer diameter and the same diameter, but the diameters of both of them. -The case where the dimensions are different will be described in the seventh and eighth embodiments described later.

As described above, in the sample holder 10 of the first embodiment in which the base plate 2 can be divided into the upper first support 2A and the lower second support 2B, the refrigerant flow path R is formed. The groove structure or the groove structure portion is formed on the lower surface of the first support 2A facing the second support 2B in an upward concave shape, that is, in a groove shape that opens downward to the lower surface.

The heat insulating material 3 that insulates between the first support 2A and the second support 2B is arranged between the first support 2A and the second support 2B, and is arranged between the first support 2A and the second support 2B, and is the lower surface of the first support 2A. By covering or closing the opening of the groove structure that opens on the lower surface, the leakage of the refrigerant from the refrigerant flow path R is prevented. As a result, the area of contact between the first support 2A and the heat insulating material 3 can be reduced. As a result, it is possible to make it difficult for the heat of the external environment below the sample holder to be transferred to the sample.

As the material constituting the heat insulating material 3, for example, a foam made of resin or the like can be preferably used. Specific examples include a silicone resin-based adhesive, a foam (sheet) made of urethane resin, and a non-woven fabric made of polyester resin.

Further, as the material constituting the heat insulating material 3 described above, a material having a lower coefficient of linear expansion than the material (aluminum in this example) constituting the base plate 2 (including the first support 2A and the second support 2B) is selected. Has been done. As a result, the stress transmitted from the first support 2A side to the second support 2B side or the stress transmitted from the second support 2B side to the first support 2A side is relaxed, so that the heat insulating material 3 is peeled off or peeled off. It can be suppressed from occurring.

According to the above configuration of the sample holder 10, it is possible to prevent the sample (not shown) held on the sample holding surface 1a from being affected by heat or temperature from the external environment below the sample holder 10. Can be done. Therefore, in the sample holder 10 of the first embodiment, the sample temperature is changed by the heating device such as the heater H built in the ceramic substrate 1 and the cooling device using the refrigerant flowing in the refrigerant flow path R, and the temperature in the sample. Uniformity of distribution (uniform heat) can be quickly achieved and maintained.

Conventionally, when the heat insulating material 3 is provided above the refrigerant flow path R, the heat insulating material 3 is located between the refrigerant flow path R and the sample holding surface (upper surface 1a), so that the sample holding surface can be cooled by the refrigerant. There was a risk of being hindered.

However, according to the present disclosure, since the heat insulating material 3 is located below or below the refrigerant flow path R, the heat insulating material is arranged between the refrigerant flow path R and the sample holding surface. Without this, it is possible to suppress the influence of heat or temperature from the external environment below the sample holder 10. As a result, the soaking of the sample could be achieved quickly and efficiently without hindering the cooling of the sample holding surface by the refrigerant.

The arrangement of the heat insulating material 3 may be arranged below or below the refrigerant flow path R, and various changes can be made.

For example, in the case of the sample holder 20 of the second embodiment shown in FIG. 4, the refrigerant flow path R is arranged not on the lower surface of the first support 2A but near the center in the vertical (height) direction of the first support 2A. Has been done. In this case as well, if the heat insulating material 3 is arranged between the first support 2A and the second support 2B as in the sample holder 10, the same effect as that of the first embodiment can be obtained.

Further, as in the sample holder 30 of the third embodiment shown in FIG. 5, a heat insulating material is provided on the lower surface (bottom surface) of the sample holder 30, that is, the lower surface of the second support 2B separated below the refrigerant flow path R. Even if 3 is attached, the same effect as that of the first embodiment can be obtained.

Further, as in the sample holder 40 of the fourth embodiment shown in FIG. 6, the sample holder 50 of the fifth embodiment shown in FIG. 7, and the sample holder 60 of the sixth embodiment shown in FIG. 8, the heat insulating material 3 is further formed. The same applies when the end portion (end face) of the sample holder is not exposed on the end face of the sample holder and the entire heat insulating material 3 is formed so as to be buried in the sample holder.

That is, in the case of the sample holder 40 of the fourth embodiment shown in FIG. 6, the heat insulating material 3 abuts on the lower side of the groove structure portion of the refrigerant flow path R as in the sample holder 10 of the first embodiment. Have been placed.

Further, in the case of the sample holder 50 of the fifth embodiment shown in FIG. 7, the member above the sample holder 50 (the first support in the sample holder 20 of the second embodiment) along the divisible position shown by the dotted line in the figure. The heat insulating material 3 is fitted in the space of the upward concave portion (opening is downward) formed on the lower surface of the body 2A).

Further, also in the case of the sample holder 60 of the sixth embodiment shown in FIG. 8, the member on the side thereof (the third member of the sample holder 20 of the second embodiment) along the divisible position shown by the dotted line in the figure. The heat insulating material 3 is fitted in the space of the concave portion (opening upward) formed on the upper surface of the 2 support 2B).

Even in the above-described embodiment in which the entire heat insulating material 3 is buried in the sample holders 40, 50, 60, the heat insulating material 3 is located below or below the refrigerant flow path R. Since it is arranged, the same effect as that of the first and second embodiments can be obtained.

The first and second embodiments described above describe a case where the upper first support 2A and the lower second support 2B constituting the base plate 2 have the same outer shape and the same diameter. However, next, a case where the diameter of the first support 2A is different from the diameter of the second support 2B, that is, both are not the same diameter will be described.

The seventh embodiment shown in FIG. 9 is a diagram for explaining the sample holder 70 in which the diameter of the lower second support 2B is larger than the diameter of the upper first support 2A, and is the eighth embodiment shown in FIG. The embodiment is a diagram illustrating a sample holder 80 in which the diameter of the lower second support 2B is smaller than the diameter of the upper first support 2A.

First, in the sample holder 70 shown in FIG. 9A, the heat insulating material 3 is arranged at a position below the refrigerant flow path R and above the lower surface of the base plate 2 (second support 2B). It is installed. Further, the horizontal end surface 3a of the heat insulating material 3 is exposed from the end surface 2c of the base plate 2.

Here, the diameter of the first support 2A constituting the base plate 2 is smaller than the diameter of the second support 2B. Therefore, the volume of the first support 2A close to the heater can be reduced and the volume of the second support 2B can be increased. In other words, the heat capacity of the second support 2B can be increased while reducing the thermal expansion of the first support 2A close to the heater.

Therefore, with this configuration, stress is concentrated between the first support 2A and the second support 2B due to thermal expansion of the first support 2A, and the possibility of damage is reduced while reducing the possibility of damage to the lower part of the sample holder. It is possible to make it difficult for the heat of the external environment to be transferred to the sample.

In addition, as shown in FIG. 9B, the end surface 3a of the heat insulating material 3 is an inclined surface that is inclined with respect to the vertical direction (vertical direction). That is, in the heat insulating material 3, the portion in contact with the first support 2A located near the heater is small, and the portion in contact with the second support 2B located near the external device below the sample holder is large. ..

As a result, stress is concentrated between the first support 2A and the heat insulating material 3 due to the thermal expansion of the first support 2A, and the heat of the external environment below the sample holder is reduced while reducing the risk of damage. It is possible to make it difficult to transmit to the first support 2A via the second support 2B.

As shown in FIG. 9C, the end surface 3a of the heat insulating material 3 may be formed of a curved curved surface.

In this way, by making the shape of the end surface 3a of the heat insulating material 3 into a shape in which stress is not concentrated on the corners, the heat insulating material 3 is generated from the end portion (exposed portion) of the heat insulating material 3. , The occurrence of peeling from the first support 2A or the second support 2B can be suppressed.

The same applies when the diameter of the first support 2A is larger than the diameter of the second support 2B. That is, in the sample holder 80 shown in FIG. 10A, the end surface 3a of the heat insulating material 3 exposed from the end surface 2c of the base plate 2 is in the vertical direction (vertical direction) as shown in FIG. 10B. It is an inclined surface that slopes.

As in the seventh embodiment, the end face 3a of the heat insulating material 3 of the sample holder 80 may also have a curved curved surface as shown in FIG. 10C.

With the above configuration, it is possible to suppress the peeling of the heat insulating material 3 that occurs starting from the end portion (exposed portion) of the heat insulating material 3 due to the concentration of stress.

1 Ceramic substrate 1a Upper surface of the substrate (sample holding surface)
2 Base plate 2A 1st support 2B 2nd support 2c End face 3 Insulation material 3a End face 4 Joining material 10, 20, 30, 40, 50, 60, 70, 80 Sample holder H Heater R Refrigerant flow path

Claims (6)

A flat sample holding member having an upper surface on which a sample can be placed,
A support member that supports the sample holding member from below, and
The flow path of the refrigerant formed inside the support member and
A sample holder comprising a heat insulating material disposed below the flow path of the refrigerant. The heat insulating material is disposed at a position below the flow path of the refrigerant and above the lower surface of the support member, and the horizontal end surface of the heat insulating material is exposed from the end surface of the support member. The sample holder according to claim 1. The sample holder according to claim 2, wherein the horizontal end face is formed of an inclined surface or a curved surface that is inclined with respect to the vertical direction. The sample holder according to any one of claims 1 to 3, wherein the heat insulating material has a coefficient of linear expansion smaller than that of the support member. The support member includes an upper plate-shaped first support located on the sample holding member side and a plate-shaped second support located on the lower side of the first support.
The first support includes an upward concave groove structure portion that serves as a flow path for the refrigerant on the lower surface facing the second support.
The sample holder according to any one of claims 1 to 4, wherein the heat insulating material is disposed between the first support and the second support. Both the first support and the second support have a disc shape.
The sample holder according to claim 5, wherein the diameter of the disc-shaped first support is smaller than the diameter of the disc-shaped second support.