JP6957375B2 - Sample holder - Google Patents

Description

The present disclosure relates to a sample holder used when holding a sample such as a semiconductor wafer in a manufacturing process of a semiconductor integrated circuit such as plasma etching or a manufacturing process of a liquid crystal display device.

As a sample holder, for example, the electrostatic chuck described in Patent Document 1 is known. The electrostatic chuck disclosed in Patent Document 1 has a suction substrate, a heater member provided below the suction substrate, and graphite provided between the suction substrate and the heater member via an adhesive layer. It has a seat. The graphite sheet has a first graphite sheet arranged on the center side and a second graphite sheet arranged concentrically on the outer peripheral side thereof, and a heat insulating portion is provided between the two graphite sheets. Is provided.

Japanese Unexamined Patent Publication No. 2014-130908

In such an electrostatic chuck, there was concern about the adhesiveness between the adhesive layer and the heat insulating portion. Further, under the heat cycle, the difference in thermal expansion between the adhesive layer and the heat insulating portion may cause peeling between the adhesive layer and the heat insulating portion. As a result, it was difficult to improve the durability of the electrostatic chuck.

The sample holder of the present disclosure includes a plate-shaped insulating substrate, a bonding layer provided on the lower surface of the insulating substrate, a support bonded to the lower surface of the insulating substrate via the bonding layer, and the insulating substrate. It is provided with a heat generating resistor provided inside or below the surface of the support or above or inside the support.
The bonding layer has a heat conductive layer having a plurality of anisotropic heat conductors located at intervals from each other, and an adhesive layer provided on the upper surface and the lower surface of the heat conductive layer, and the heat. wherein the plurality of portions other than the anisotropic thermal conductor of the conductive layer, the adhesive layer and the main component Ri same der, the plurality of anisotropic heat conductor, each similarly a central, circular Alternatively, it has a ring shape, and at least three or more of the anisotropic heat conductors are provided, and the distance between the anisotropic heat conductors increases from the center of the heat conductive layer toward the outer periphery. It is characterized by that.

According to the sample holder of the present disclosure, the durability of the sample holder can be improved.

It is sectional drawing which shows an example of the sample holder. It is sectional drawing which shows the other example of a sample holder. It is sectional drawing of the heat conduction layer in the sample holder of another example. It is sectional drawing which shows the other example of a sample holder. It is sectional drawing which shows the other example of a sample holder. It is sectional drawing which shows the other example of a sample holder. It is sectional drawing which shows the other example of a sample holder. It is sectional drawing which shows the other example of a sample holder.

An example of the sample holder 10 of the present embodiment will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a sample holder 10 which is an example of the present disclosure. As shown in FIG. 1, the sample holder 10 includes an insulating substrate 1, a bonding layer 2, a support 3, and a heat generating resistor 4.

The insulating substrate 1 is a member for holding a sample. The insulating substrate 1 is a plate-shaped member, for example, a disk-shaped member. For example, the upper surface of the insulating substrate 1 is the sample holding surface 11, and the lower surface is bonded to the support 3 via the bonding layer 2. The "upper surface" and "lower surface" referred to here are used for convenience of explanation, and do not limit the embodiment of the sample holder 10. The insulating substrate 1 is made of a member such as aluminum nitride or alumina. The insulating substrate 1 may have, for example, an electrode for electrostatic adsorption inside. The dimensions of the insulating substrate 1 can be, for example, when the insulating substrate 1 has a disk shape, the thickness can be 2 to 10 mm and the diameter can be 100 to 500 mm.

The support 3 is a member for supporting the insulating substrate 1. The support 3 is, for example, a disk-shaped member whose upper surface is bonded to the lower surface of the insulating substrate 1 via the bonding layer 2. The support 3 is a member made of a metal such as aluminum or magnesium, and may have a flow path inside. Further, the support 3 may be made of an insulating material such as ceramics, and may further have a metal substrate 8 on the lower surface. The dimensions of the support 3 can be, for example, when the support 3 has a disk shape, the thickness can be 3 to 100 mm and the diameter can be 100 to 500 mm. The support 3 may have a plurality of through holes for providing the lead terminals 7.

The heat generation resistor 4 is a member for heating the sample. The heat generation resistor 4 is provided inside or below the insulating substrate 1 or above or inside the support 3. The heat generation resistor 4 is, for example, a linear member having a plurality of folded portions. The heat generation resistor 4 is made of a metal material such as silver or palladium. The heat generation resistor 4 may contain a glass component. The heat generation resistor 4 can have a thickness of 10 to 100 μmm, a width of 1 to 5 mm, and a length of 1000 to 20000 mm, for example. The heat generation resistor 4 may be electrically connected to the lead terminal 7.

The bonding layer 2 is a member for bonding the insulating substrate 1 and the support 3. The bonding layer 2 has a heat conductive layer 22 having a plurality of anisotropic heat conductors 5, and an adhesive layer 21 provided on the upper surface and the lower surface of the heat conductive layer 22. Since the bonding layer 2 has the heat conductive layer 22 having the plurality of anisotropic heat conductors 5, the heat generated by the heat generating resistor 4 is diffused in the direction parallel to the sample holding surface 11. be able to. As a result, the heat equalizing property of the sample holding surface 11 can be improved.

The heat conductive layer 22 has a plurality of anisotropic heat conductors 5 and a portion other than the plurality of anisotropic heat conductors 5 (hereinafter, also referred to as a connecting portion 6). The plurality of anisotropic heat conductors 5 are arranged at intervals from each other. The anisotropic heat conductor 5 is, for example, a plate-shaped or sheet-shaped member. The anisotropic heat conductor 5 is a member having an anisotropic thermal conductivity, such as a graphite sheet. The surface of the anisotropic heat conductor 5 may be coated with, for example, plating. In this case, the anisotropic heat conductor 5 is used, including a coating such as plating. The anisotropic heat conductor 5 may have a plurality of through holes for providing the lead terminal 7, for example, when the anisotropic heat conductor 5 is located below the heat generating resistor 4. good.

The plurality of anisotropic heat conductors 5 may be each portion of one sheet having a diameter of 100 to 500 mm divided into a plurality of sheets, for example, when the sample holding surface 11 has a circular shape. By arranging the plurality of anisotropic thermal conductors 5 at intervals from each other, it is possible to reduce the possibility that thermal stress is concentrated when the sheet thermally expands. Further, the plurality of anisotropic heat conductors 5 may be partially in contact with each other.

Here, the heat conductive layer 22 is a layered region including all of the plurality of anisotropic heat conductors 5 in the bonding layer 2. Specifically, as shown in FIG. 2, when a plurality of anisotropic heat conductors 5 are sheet-like members and are provided in a staggered manner, the heat conductive layer 22 is located above the anisotropic side. It is a region surrounded by the upper surface of the sex heat conductor 5 and the lower surface of the anisotropic heat conductor 5 located below. The thickness of the heat conductive layer 22 can be, for example, 1 to 10 mm.

Further, as shown in FIG. 2, when a plurality of anisotropic heat conductors 5 are sheet-like members and are provided in a staggered manner, the bonding layer 2 and the plurality of anisotropic heat conductors 5 are combined. Each boundary surface can be shifted in the direction perpendicular to the sample holding surface 11. Therefore, stress is concentrated on the boundary surface between the bonding layer 2 and the plurality of anisotropic heat conductors 5, and the possibility that the bonding layer 2 and the plurality of anisotropic heat conductors 5 are separated from each other at the boundary surface is reduced. Can be done. As a result, the durability of the sample holder 10 can be improved. The term "step difference" as used herein means that the anisotropic heat conductor 5 exposed on the lower surface of the heat conductive layer 22 and the anisotropic heat conductor 5 exposed on the upper surface of the heat conductive layer 22 are alternately located. It means that it is.

The adhesive layer 21 is a member made of, for example, epoxy or silicone. The thickness of the adhesive layer 21 can be 0.1 to 5 mm, respectively. Here, for example, when the heat generating resistor 4 is provided on the lower surface of the insulating substrate 1, the distance from the lower surface of the insulating substrate 1 to the upper surface of the heat conductive layer 22 is defined as the thickness of the adhesive layer 21. Further, for example, when the heat generating resistor 4 is provided on the upper surface of the support 3, the distance from the upper surface of the support 3 to the lower surface of the heat conductive layer 22 is defined as the thickness of the adhesive layer 21.

According to the sample holder 10 of the present disclosure, the portions (connecting portions 6) of the heat conductive layer 22 other than the plurality of anisotropic heat conductors 5 have the same main components as the adhesive layer 21. Thereby, the adhesiveness of the connecting portion 6 can be improved. Further, the difference between the coefficient of thermal expansion of the connecting portion 6 and the thermal conductivity of the adhesive layer 21 can be reduced. Therefore, it is possible to reduce the possibility that thermal stress is generated between the connecting portion 6 and the adhesive layer 21 under the heat cycle. As a result, the durability of the sample holder 10 can be improved.

The "main component" here means the component having the largest proportion among the components constituting the member. A Fourier transform infrared spectrophotometer (model number: Prestige-21) manufactured by Shimadzu Corporation can be used for component analysis of the adhesive layer 21 and the connecting portion 6. Specifically, the main component can be investigated by the interatomic vibration constituting the main component absorbing infrared rays having a unique wavelength and estimating the composition (functional group). The connecting portion 6 can be cut out from the adhesive layer 21 by removing the insulating substrate 1 and the support 3 of the sample holder 10 by grinding, or by cutting the adhesive layer 21 with a wire cutter or the like.

Further, as shown in FIG. 3, the plurality of anisotropic heat conductors 5 may have a circular shape or an annular shape, each having the same center. As a result, the heat equalizing property of the sample holding surface 11 in the circumferential direction can be improved.

Further, the plurality of anisotropic heat conductors 5 may have a circular shape or an annular shape, which may be divided into a plurality of parts. As a result, each portion of the plurality of anisotropic heat conductors 5 can be made smaller. Therefore, the thermal stress generated in each anisotropic heat conductor 5 can be reduced. As a result, the durability of the sample holder 10 can be improved.

Further, as shown in FIG. 3, at least three anisotropic heat conductors 5 are provided, and the distance between the anisotropic heat conductors 5 increases from the center of the heat conductive layer 22 toward the outer periphery. It may be. Since the annular-shaped anisotropic heat conductor 5 thermally expands more on the outside than on the inside, such a configuration reduces the stress caused by the thermal expansion on the outside of the anisotropic heat conductor 5. Can be done. Therefore, it is possible to reduce the possibility of damage occurring in the vicinity of the anisotropic heat conductor 5. As a result, the durability of the sample holder 10 can be improved.

Specifically, as shown in FIG. 3, when the plurality of anisotropic heat conductors 5 are three ring-shaped members, the outer diameter of the ring closest to the center is 91 mm, and the second center is the outer diameter. The inner diameter of the closest ring can be 100 mm, the outer diameter of the ring closest to the center can be 191 mm, and the inner diameter of the ring farthest from the center can be 200 mm.

Further, as shown in FIG. 4, the plurality of anisotropic heat conductors 5 may not be exposed on the outer peripheral surface of the heat conductive layer 22. As a result, it is possible to reduce the possibility that the heat generated by the heat generating resistor 4 escapes to the outside via the anisotropic heat conductor 5. As a result, the efficiency of heating the sample holding surface 11 can be improved. Specifically, the portion exposed on the outer peripheral surface of the heat conductive layer 22 may be the connecting portion 6.

Further, as shown in FIG. 4, when the anisotropic heat conductor 5 has a through hole, the portion of the heat conductive layer 22 exposed to the through hole is covered with the connecting portion 6. May be good. As a result, it is possible to reduce the possibility that heat is drawn from the through hole. As a result, the heat equalizing property of the sample holding surface 11 can be improved.

Further, as shown in FIG. 4, the heat generating resistor 4 is located above the plurality of anisotropic heat conductors 5, and the lead terminal 7 electrically connected to the heat generating resistor 4 is anisotropic. It is pulled out below the support 3 through the through hole provided in the anisotropic heat conductor 5, and the portion of the heat conductive layer 22 exposed inside the through hole may be covered with the connecting portion 6. .. As a result, the anisotropic heat conductor 5 that conducts heat more easily than the connecting portion 6 can be configured so as not to be exposed to the through hole. Therefore, it is possible to reduce the possibility that heat is drawn from the lead terminal 7. As a result, the heat equalizing property of the sample holding surface 11 can be improved.

Further, as shown in FIG. 5, the adhesive layer 21 may be thinner at a portion located on the upper surface than at a portion located on the lower surface of the heat conductive layer 22. As a result, the distance between the anisotropic heat conductor 5 and the sample holding surface 11 can be reduced while ensuring the thickness of the entire bonding layer 2. As a result, the heat equalizing property of the sample holding surface 11 can be improved while increasing the durability of the sample holding tool 10. As the specific thickness of the adhesive layer 21, the portion located on the lower surface of the heat conductive layer 22 can be set to 2 mm, and the portion located on the upper surface of the heat conductive layer 22 can be set to 0.1 mm. In particular, when the heat generating resistor 4 is located between the anisotropic heat conductor 5 and the sample holding surface 11, the distance between the heat generating resistor 4 and the anisotropic heat conductor 5 can be shortened. , The heat soothing property of the sample holding surface 11 can be further improved.

Further, as shown in FIG. 5, the heat generating resistor 4 may be provided inside or on the lower surface of the insulating substrate 1. As a result, the distance between the heat generating resistor 4 and the sample holding surface 11 can be made closer than in the case where the heat generating resistor 4 is provided on the upper surface or inside of the support 3. Therefore, the heat generated by the heat generating resistor 4 can be efficiently transferred to the sample holding surface 11. As a result, the efficiency of heating the sample can be increased. Further, the sample holder 10 may further have a metal substrate 8 on the lower surface of the support 3. The dimensions of the metal substrate 8 can be, for example, when the metal substrate 8 has a disk shape, the thickness can be 10 to 100 mm and the diameter can be 100 to 500 mm.

Further, as shown in FIGS. 6 and 7, the heat generating resistor 4 may be provided on the upper surface or inside of the support 3. As a result, the anisotropic heat conductor 5 can be provided between the heat generating resistor 4 and the sample holding surface 11. Therefore, the heat generated by the heat generating resistor 4 can be efficiently diffused in the plane direction by the anisotropic heat conductor 5 and transferred to the sample holding surface 11. As a result, the heat equalizing property of the sample holding surface 11 can be improved.

Further, as shown in FIG. 8, the anisotropic heat conductor 5 may have a curved side surface. In this case, it is possible to reduce the possibility of peeling from the corner portion of the anisotropic heat conductor 5 where stress is particularly likely to be concentrated. As a result, the durability of the sample holder 10 can be improved.

1: Insulating substrate 11: Sample holding surface 2: Bonding layer 21: Adhesive layer 22: Heat conduction layer 3: Support 4: Heat generation resistor 5: Anisotropic heat conductor 6: Connection part 7: Lead terminal 8: Metal Base 10: Sample holder

Claims (5)

A plate-shaped insulating substrate, a bonding layer provided on the lower surface of the insulating substrate, a support bonded to the lower surface of the insulating substrate via the bonding layer, and the inside or lower surface of the insulating substrate or the support. It is equipped with a heat generating resistor provided on the upper surface or inside of the
The bonding layer has a heat conductive layer having a plurality of anisotropic heat conductors located at intervals from each other, and an adhesive layer provided on the upper surface and the lower surface of the heat conductive layer.
Wherein the plurality of portions other than the anisotropic heat conductor of the heat conducting layer, the adhesive layer and the main component Ri same der,
The plurality of anisotropic heat conductors have a circular shape or an annular shape, each having the same center, and at least three or more of the anisotropic heat conductors are provided, and the anisotropic heat is provided. interval conductor each other, the sample holder, wherein greater Do Rukoto toward the outer periphery from the center of the heat conducting layer. The sample holder according to claim 1, wherein the plurality of anisotropic heat conductors are not exposed on the outer peripheral surface of the heat conductive layer. The sample holder according to claim 1 or 2 , wherein the adhesive layer has a thinner portion located on the upper surface than a portion located on the lower surface of the heat conductive layer. The sample holder according to any one of claims 1 to 3 , wherein the heat generating resistor is provided inside or on the lower surface of the insulating substrate. The sample holder according to any one of claims 1 to 3 , wherein the heat generating resistor is provided on the upper surface or inside of the support.

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