WAFER TEMPERATURE CONTROL DEVICE

A wafer temperature control device includes a temperature control sheet; and a top plate. The temperature control sheet includes a plurality of temperature control portions. The plurality of temperature control portions are divided from each other via a division region in the same plane. The plurality of temperature control portions are each independently controllable in temperature. The top plate includes a plate body stacked on the temperature control sheet. A surface of the plate body serves as a placement surface for a semiconductor wafer, the surface being opposite the temperature control sheet. The top plate includes a heat insulating portion. The heat insulating portion is disposed at a position corresponding to the division region in the plate body, when viewed in a stacking direction of the temperature control sheet and the top plate. The heat insulating portion has a thermal conductivity lower than a thermal conductivity of the plate body.

TECHNICAL FIELD

The present invention relates to a wafer temperature control device.

Priority is claimed on Japanese Patent Application No. 2020-153856, filed on Sep. 14, 2020, the content of which is incorporated herein by reference.

BACKGROUND ART

Patent Document 1 discloses a circular cooling plate that cools a wafer. The circular cooling plate includes a thermo-module in which a plurality of Peltier elements are disposed between a pair of heat transfer plates. Furthermore, in Patent Document 1, by devising the shape of the pair of heat transfer plates or a disposition of the plurality of Peltier elements in various ways, it is possible dispose the thermo-module as close to the wafer as possible, to improve cooling capacity and to reduce temperature variation.

CITATION LIST

Patent Document

Patent Document 1

SUMMARY OF INVENTION

Technical Problem

In a wafer temperature control device that controls temperature of a wafer as disclosed in Patent Document 1, in order to suppress an influence on a back surface of the wafer, it is desirable that the back surface of the wafer is supported from below by a smooth surface without irregularities.

Further, in the wafer temperature control device described above, instead of reducing temperature variation in the wafer, it is desirable that a plurality of zones be set within a wafer surface and temperature is independently controlled for each zone. However, even when an attempt is made to differentiate the temperature of the zones adjacent to each other, a desired temperature may not be obtainable in the vicinity of the boundary of the adjacent zones due to heat conduction in the smooth surface supporting the wafer.

The present invention is conceived in view of such a problem, and an object of the present invention is to provide a wafer temperature control device capable of favorably controlling temperature for each of a plurality of zones.

Solution to Problem

A wafer temperature control device according to one aspect of the present invention includes: a temperature control sheet; and a top plate. The temperature control sheet is configured to include a plurality of temperature control portions. The plurality of temperature control portions are divided from each other via a division region in the same plane. The plurality of temperature control portions are each independently controllable in temperature. The top plate is configured to include a plate body stacked on the temperature control sheet. A surface of the plate body serves as a placement surface for a semiconductor wafer, the surface being opposite the temperature control sheet. The top plate includes a heat insulating portion. The heat insulating portion is disposed at a position corresponding to the division region in the plate body, when viewed in a stacking direction of the temperature control sheet and the top plate. The heat insulating portion has a thermal conductivity lower than the thermal conductivity of the plate body.

Advantageous Effects of Invention

According to the present invention, it is possible to favorably control the temperature for each of a plurality of the division regions.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described in detail below with reference toFIGS.1to4.

A wafer temperature control device (hereinafter, simply referred to as a temperature control device) according to the present embodiment is installed in, for example, a semiconductor manufacturing apparatus. The temperature control device supports a semiconductor wafer from below, which is subjected to predetermined processing such as plasma processing or etching processing in the semiconductor manufacturing apparatus. The temperature control device controls the temperature of the semiconductor wafer to a temperature suitable for predetermined processing.

FIG.1is an elevational cross-sectional view showing a schematic configuration of a wafer temperature control device according to an embodiment of the present invention.

As shown inFIG.1, a temperature control device1A according to the present embodiment is supported by a chamber5of a semiconductor manufacturing apparatus. The temperature control device1A partitions an upper space6A that is the inside of the chamber5and a lower space6B that is the outside of the chamber5. The upper space6A is disposed above the temperature control device1A in an up-down direction Dv. The lower space6B is disposed below the temperature control device1A in the up-down direction Dv. In the present embodiment, for example, the upper space6A is vacuum-drawn to a degree of vacuum suitable for predetermined processing.

The temperature control device1A includes a temperature control sheet2A, a top plate3, and a cooling plate8. The temperature control sheet2A, the top plate3, and the cooling plate8are stacked and disposed in the up-down direction Dv.

FIG.2is a cross-sectional view taken along line I-I ofFIG.1.

As shown inFIG.2, in the present embodiment, a contour of the temperature control sheet2A when viewed in the up-down direction Dv (direction perpendicular to the drawing sheet ofFIG.2) has, for example, a circular shape. The temperature control sheet2A includes a plurality of temperature control portions21. The plurality of temperature control portions21in the present embodiment are separated from each other in the same plane (horizontal plane) orthogonal to a stacking direction Ds of the temperature control sheet2A and the top plate3(the up-down direction Dv), to interpose division regions22therebetween. In the present embodiment, the plurality of temperature control portions21include, for example, an inner peripheral temperature control portion21A, intermediate temperature control portions21B and21C, and outer peripheral temperature control portions21D to21G.

The inner peripheral temperature control portion21A is disposed at a circular central portion of the temperature control sheet2A when viewed in the up-down direction Dv. The inner peripheral temperature control portion21A shown as an example in the present embodiment has a circular shape when viewed in the up-down direction Dv.

The intermediate temperature control portions21B and21C are disposed outside the inner peripheral temperature control portion21A in a radial direction Dr of the temperature control sheet2A, and are disposed to surround the temperature control sheet2A. Specifically, each of the intermediate temperature control portions21B and21C in the present embodiment is formed in a semicircular arc shape. Then, the intermediate temperature control portions21B and21C each having a semicircular arc shape are arranged in a circumferential direction Dc to form a substantially annular shape.

The inner peripheral temperature control portion21A and the intermediate temperature control portions21B and21C are separated from each other in the radial direction Dr via a first division region22P having an annular shape that is continuous in the circumferential direction Dc of the temperature control sheet2A. In addition, the intermediate temperature control portion21B and the intermediate temperature control portion21C are disposed at intervals from each other in the circumferential direction Dc with second division regions22Q interposed therebetween. Each of the second division regions22Q extends in the radial direction Dr to connect the first division region22P and a third division region22R to be described later.

The outer peripheral temperature control portions21D to21G are disposed outside the intermediate temperature control portions21B and21C in the radial direction Dr of the intermediate temperature control portions21B and21C and are disposed to surround the intermediate temperature control portions21B and21C. Specifically, each of the outer peripheral temperature control portions21D to21G in the present embodiment is formed in an arc shape. Then, the outer peripheral temperature control portions21D to21G each having an arc shape are arranged in the circumferential direction Dc to form a substantially annular shape. The outer peripheral temperature control portions21D to21G are disposed at an outermost peripheral portion of the temperature control sheet2A.

The intermediate temperature control portions21B and21C and the outer peripheral temperature control portions21D to21G are separated from each other in the radial direction Dr via the third division region22R having an annular shape that is continuous in the circumferential direction Dc. In addition, the outer peripheral temperature control portions21D to21G adjacent to each other in the circumferential direction Dc are separated from each other via four fourth division regions22S disposed at intervals from each other in the circumferential direction Dc. Each of the fourth division regions22S extends outward from the third division region22R in the radial direction Dr.

Each of the plurality of temperature control portions21(the inner peripheral temperature control portion21A, the intermediate temperature control portions21B and21C, and the outer peripheral temperature control portions21D to21G) is formed of, for example, a Peltier element or a sheet piece23with a built-in Peltier element. The temperature control sheet2A includes a plurality of the sheet pieces23each having a predetermined shape. The plurality of sheet pieces23are disposed at intervals from each other such that the temperature control sheet2A forms the first division region22P, the second division regions22Q, the third division region22R, and the fourth division regions22S.

Each of the plurality of temperature control portions21(sheet pieces23) is controllable in temperature by an external controller (not shown). For example, the controller (not shown) controls energization of the Peltier element of each of the temperature control portions21(sheet pieces23) to cause the plurality of temperature control portions21to be each independently controllable in temperature (temperature control).

As shown inFIG.1, the cooling plate8is stacked on a lower side of the temperature control sheet2A in the up-down direction Dv. The cooling plate8in the present embodiment is disposed on a side opposite the top plate3in the stacking direction Ds. The cooling plate8is made of, for example, metal such as copper or aluminum, resin, or ceramic. The cooling plate8is disposed in close contact with a lower surface of the temperature control sheet2A. The cooling plate8absorbs heat emitted downward from the temperature control sheet2A in the up-down direction Dv.

The top plate3is stacked on an upper side of the temperature control sheet2A in the up-down direction Dv. The top plate3in the present embodiment is disposed on a side opposite the cooling plate8in the stacking direction Ds. In other words, a lower surface of the top plate3is in contact with an upper surface of the temperature control sheet2A. The top plate3includes a plate body31and a heat insulating portion32.

FIG.3is a cross-sectional view taken along line II-II ofFIG.1.

As shown inFIG.3, in the present embodiment, a contour of the plate body31when viewed in the up-down direction Dv (direction orthogonal to the drawing sheet ofFIG.3) has, for example, a circular shape. The plate body31is formed to cover the entirety of the temperature control sheet2A from above (refer toFIG.2). The plate body31is made of, for example, a material such as an aluminum alloy or ceramic. A surface of the plate body31serves as a placement surface31ffor a semiconductor wafer, the surface being opposite the temperature control sheet2A. The placement surface31fis a smooth surface which intersects (is orthogonal to) the stacking direction Ds and in which a groove, a recessed portion, or the like is not formed.

As shown inFIGS.1and3, the heat insulating portion32is formed inside the plate body31. The heat insulating portion32is disposed at a position corresponding to the division regions22(in other words, a position where the heat insulating portion32overlaps the division regions22in the up-down direction Dv), when viewed in the stacking direction Ds (the up-down direction Dv) of the temperature control sheet2A and the top plate3. The heat insulating portion32in the present embodiment includes a space33, a heat insulator34, a fluid supply portion36, and a fluid discharge portion37.

The space33is formed inside the plate body31. Namely, the space33is not exposed (open) to the placement surface31fof the plate body31and to a facing surface31gfacing the temperature control sheet2A on a side opposite the placement surface31f. The space33is formed at a predetermined interval from each of the placement surface31fand the facing surface31gof the plate body31in the stacking direction Ds. The space33is continuously formed inside the plate body31in a direction along a horizontal plane orthogonal to the stacking direction Ds. The space33in the present embodiment is formed inside the plate body31at a position where the space33overlaps the division regions22when viewed in the stacking direction Ds (the up-down direction Dv). The space33includes a first space33P, second spaces33Q, a third space33R, and fourth spaces33S.

The first space33P has an annular shape when viewed in the stacking direction Ds, and is formed at a position where the first space33P overlaps the first division region22P.

The second spaces33Q extend in the radial direction Dr. The second spaces33Q are disposed at intervals in the circumferential direction Dc at two locations. The second spaces33Q in the present embodiment are disposed on an extension line extending in the radial direction Dr. The second spaces33Q are formed at positions where the second spaces33Q overlap the second division regions22Q when viewed in the stacking direction Ds. The second spaces33Q allow the first space33P and the third space33R to be described later to communicate with each other.

The third space33R has an annular shape when viewed in the stacking direction Ds and is formed at a position where the third space33R overlaps the third division region22R.

The fourth spaces33S extend outward from the third space33R in the radial direction Dr. The fourth spaces33S are disposed at intervals in the circumferential direction Dc at four locations. The fourth spaces33S are formed at positions where the fourth spaces33S overlap the fourth division regions22S when viewed in the stacking direction Ds.

The heat insulator34is disposed in the space33. In the present embodiment, for example, a liquid or gaseous fluid can be used as the heat insulator34. The heat insulator34formed of a fluid is supplied from the outside of the temperature control device1A, flows such that the space33is filled with the heat insulator34, and is then discharged to the outside of the temperature control device1A. As the heat insulator34, a material having a thermal conductivity lower than that of the plate body31, such as liquid such as air, nitrogen gas, an inert gas, water, and a fluorine-based refrigerant, can be used.

FIG.4is a plan view of the top plate of the temperature control device.

The top plate3is divided into a plurality of zones S shown inFIGS.1and4by the heat insulating portion32when viewed in the stacking direction Ds (direction orthogonal to the drawing sheet ofFIG.4). When viewed in the stacking direction Ds, the plurality of zones S correspond to (in other words, overlap in the up-down direction Dv) the plurality of temperature control portions21(the inner peripheral temperature control portion21A, the intermediate temperature control portions21B and21C, and the outer peripheral temperature control portions21D to21G) shown inFIG.2. As the plurality of zones S, an inner peripheral zone S1corresponding to the inner peripheral temperature control portion21A, intermediate zones S2and S3corresponding to the intermediate temperature control portions21B and21C, and outer peripheral zones S4to S7corresponding to the outer peripheral temperature control portions21D to21G are provided.

The fluid supply portion36supplies the fluid that is the heat insulator34, into the space33from the outside of the temperature control device1A. The fluid discharge portion37discharges the fluid that is the heat insulator34, from the space33to the outside of the temperature control device1A. One end of the fluid supply portion36and one end of the fluid discharge portion37each communicate with the space33. The other end of the fluid supply portion36and the other end of the fluid discharge portion37are each open toward the outside of the temperature control device1A.

The fluid supply portion36and the fluid discharge portion37in the present embodiment each extend downward from the space33formed in the plate body31, in the stacking direction Ds (the up-down direction Dv). The fluid supply portion36and the fluid discharge portion37in the present embodiment are each disposed to communicate with the fourth spaces33S. The fluid supply portion36and the fluid discharge portion37penetrate through the temperature control sheet2A and through the cooling plate8in the stacking direction Ds, and are open to a lower surface of the cooling plate8.

A feed pipe (not shown) through which the heat insulator34is fed from the outside by a pump (not shown) or the like is connected to the fluid supply portion36. In addition, a discharge pipe (not shown) for discharging the heat insulator34to the outside is connected to the fluid discharge portion37.

Incidentally, the heat insulator34to be fed into the space33from the fluid supply portion36may be configured to be controllable in temperature, pressure, flow rate, and the like as appropriate. In that case, a heat exchanger, a pump, or the like that controls temperature of the heat insulator34may be provided outside.

The temperature control device1A includes the plurality of temperature control portions21that are each independently controllable in temperature. For this reason, the temperature of a semiconductor wafer placed on the placement surface31fof the plate body31of the top plate3is controllable to different desired temperatures for each of the plurality of zones S. In addition, the top plate3includes the heat insulating portion32disposed at a position corresponding to the division regions22of the temperature control sheet2A. For this reason, in the top plate3, heat transferred from one temperature control portion21of the temperature control sheet2A to one zone S is prevented from moving to another zone S to which heat from another temperature control portion21is transferred. Therefore, the temperature is favorably controllable for each of the plurality of zones S.

In addition, in the temperature control device1A, the heat insulating portion32includes the space33. Accordingly, inside the top plate3, heat conduction between the adjacent zones S among the plurality of zones S corresponding to the plurality of temperature control portions21in the stacking direction Ds can be suppressed.

In addition, in the temperature control device1A, the heat insulator34having a thermal conductivity lower than that of the plate body31exists in the space33. Accordingly, heat conduction between the adjacent zones S of the top plate3can be much further suppressed.

In addition, in the temperature control device1A, the fluid as the heat insulator34is fed into the space33from the outside through the fluid supply portion36, and the fluid as the heat insulator34that has flowed through the space33is discharged from the fluid discharge portion37. Accordingly, a change in the temperature of the heat insulator34caused by heat of the plurality of temperature control portions21can be suppressed. Therefore, heat transfer between the plurality of zones S of the top plate3can be more efficiently suppressed.

In addition, in the temperature control device1A, the fluid supply portion36and the fluid discharge portion37extend in the stacking direction Ds and penetrate through the temperature control sheet2A. For this reason, the fluid as the heat insulator34can flow into and out of the space33from the side opposite the placement surface31ffor the semiconductor wafer. In addition, heat exchanged between the zones S facing the space33can be moved in the stacking direction Ds by the fluid.

In addition, in the temperature control device1A, the placement surface31fis a smooth surface. For this reason, an influence on a back surface of the wafer can be reduced, and unlike a case where grooves or the like are formed in the placement surface31f, foreign matter or the like does not enter grooves or the like, so that cleaning or maintenance of the placement surface31fcan be easily performed.

Further, in the temperature control device1A, the temperature control sheet2A includes the plurality of sheet pieces23forming the temperature control portions21. For this reason, when the sheet pieces23adjacent to each other are disposed at intervals, the division regions22can also be easily formed.

Modification Example of Embodiment

FIG.5is an elevational cross-sectional view showing a schematic configuration of a wafer temperature control device according to a modification example of the embodiment of the present invention.

In the embodiment, a Peltier element is used as the temperature control sheet2A, but the present invention is not limited to this configuration.

For example, as shown inFIG.5, an electric heater28may be used as a temperature control sheet2B of a temperature control device1B. The electric heater28includes a plurality of sheet pieces29. Similarly to the temperature control sheet2A of the embodiment shown inFIG.2, the sheet pieces29form the plurality of temperature control portions21that are each independently controllable in temperature. The sheet pieces29are disposed at intervals from each other, so that the plurality of temperature control portions21are separated from each other via the division regions22in the same plane.

When the electric heater28is provided, a purge plate50may be disposed below from the electric heater28at an interval in the up-down direction Dv. Accordingly, a purge space51is formed between the electric heater28and the purge plate50. When the temperature of the electric heater28is to be lowered, the temperature of the electric heater28can be efficiently lowered by purging air from the outside into the purge space51.

In addition, when the purge plate50is provided, the fluid supply portion36and the fluid discharge portion37may be formed into a tubular shape, and may be provided to penetrate through the purge space51and through the purge plate50from the temperature control sheet2B.

Other Modification Examples

In the embodiment and the modification example, the plurality of temperature control portions21forming each of the temperature control sheets2A and2B are divided into the inner peripheral temperature control portion21A, the intermediate temperature control portions21B and21C, and the outer peripheral temperature control portions21D to21G, but the present invention is not limited to this configuration. The number of and the division pattern of the plurality of temperature control portions21forming the temperature control sheet2A can be changed as appropriate.

Further, the case in which in the temperature control sheet2A, the first division region22P, the second division regions22Q, the third division region22R, and the fourth division regions22S are provided has been described, but the first division region22P, the second division regions22Q, the third division region22R, and the fourth division regions22S may be omitted, and the first division region22P, the second division regions22Q, the third division region22R, and the fourth division regions22S adjacent to each other in the circumferential direction Dc and in the radial direction Dr may be brought close to each other.

In addition, the space33is not exposed (open) to the placement surface31fof the plate body31and to the facing surface31g, but the present invention is not limited to this configuration. For example, the space33may be open to the facing surface31gto communicate with the division regions22of the temperature control sheet2A. In this case, the supply of the heat insulator34to or the filling of not only the space33but also the division regions22with the heat insulator34may be performed.

Further, in the embodiment, the case where only one space33is provided has been provided as an example, but the present invention is not limited to this case. For example, the space33may be divided into a plurality of segments.

In addition, in the embodiment, the case where one fluid supply portion36and one fluid discharge portion37are provided for one space33has been provided as an example, but the present invention is not limited to this case. For example, a plurality of the fluid supply portions36and a plurality of the fluid discharge portions37may be provided for one space33.

In addition, the case where the plate body31is provided with a single space33has been described, but the plate body31may be provided with a plurality of the spaces33that do not communicate with each other, and the heat insulator34may be supplied to and discharged from the each of the spaces33.

In addition, as the heat insulating portion32, the heat insulator34formed of a fluid is supplied from the outside of the temperature control device1A, but the present invention is not limited to this configuration. For example, the space33may simply be filled (in other words, enclosed) with the heat insulator34formed of a fluid. In addition, as the heat insulating portion32, the space33may be filled with, for example, a solid-state heat insulating material such as carbon fibers having a heat insulating property. In addition, a gas having a pressure lower than the atmospheric pressure which is obtained by vacuum-drawing the space33using a vacuum pump or the like may be used as the heat insulating portion32. In addition, for example, the space33may communicate with the upper space6A. Accordingly, the heat insulating portion32can be configured by setting the space33to the same vacuum state as the upper space6A.

INDUSTRIAL APPLICABILITY

According to the present invention, it is possible to favorably control temperature for each of a plurality of the division regions.

REFERENCE SIGNS LIST