TWM448051U - Electrostatic chuck capable of sectionally regulating temperature - Google Patents

Description

Temperature-divisionally adjustable electrostatic chuck

The present invention relates to an electrostatic chuck, and more particularly to an electrostatic chuck capable of temperature-division regulation.

In the manufacturing process of a semiconductor device, in order to perform deposition processing such as deposition and etching on a wafer, an electrostatic force generated by an electrostatic chuck (ESC) is generally used to support and fix the wafer during processing.

The electrostatic chuck is typically located at the bottom of the vacuum processing chamber and typically includes a susceptor and a ceramic dielectric layer disposed on top of the susceptor. A direct current is applied to the electrodes embedded in the dielectric layer to generate an electrostatic charge to hold the wafer placed on the dielectric layer. A chiller is provided in the susceptor to control the temperature of the wafer by opening a plurality of channels through which the fluid flowing therethrough heats or cools the temperature of the electrostatic chuck.

However, for example, due to the uneven distribution of reactive gases or plasma within the processing chamber, different regions on the surface of the wafer tend to have different processing rates; for different regions arranged radially along the wafer, this non-uniform treatment is especially Obviously, for example, the processing rate of the central region of the wafer is faster, and the processing rate of the edge region of the wafer is slower, which may result in different performance of semiconductor devices formed in different regions on the wafer. The prior art often uses a change in the gas flow rate or type distribution of the wafer edge and the central region to achieve uniformity of the final treatment effect, but this method requires the inlet to have independently adjustable multi-zone gas distributors, and from gas distribution. The difference in flow or type of these gases after the gas is diffused from the wafer to the wafer processing surface is also partially attenuated for final processing. The debugging of the effect is not ideal, and it is difficult to obtain the desired processing effect by quick and direct debugging in the actual machining process. The prior art also improves the uniformity of the treatment effect by adjusting the distribution of the electric field over the entire processing surface. The adjustment of the electric field causes a change in the plasma distribution, but the actual influence on the processing process dominated by the chemical reaction is not large and does not work well. Regulating effect. Therefore, there is an urgent need in the industry for a method or apparatus that can quickly adjust the uniformity of processing by other methods.

The purpose of the present invention is to provide a temperature-divisionally adjustable electrostatic chuck in which a heating body is embedded in a position corresponding to the edge of the wafer in the dielectric layer, and the processing reaction rate of the region is accelerated by increasing the temperature of the edge of the wafer, thereby offsetting the wafer diameter. In combination with the effect of uneven processing, two sets of heat exchangers are also disposed in the base of the electrostatic chuck to further adjust the temperature of the center and edge regions of the wafer.

In order to achieve the above object, the technical proposal of the present invention is to provide a temperature-divisionally adjustable electrostatic chuck comprising a base fixedly disposed at the bottom of the vacuum processing chamber, and a dielectric layer made of a thermally conductive ceramic material disposed on the top of the base. A direct current is applied to the electrode buried in the dielectric layer to generate an electrostatic force to hold the wafer placed on the dielectric layer.

A heating body is further disposed inside the dielectric layer of the electrostatic chuck; the heating body is disposed on the top of the dielectric layer; and the heating body is disposed around the edge of the dielectric layer to correspond to the edge position of the wafer; controlling the heating body to emit heat The heat is transferred to the wafer via the dielectric layer to increase the temperature at the edge of the wafer.

A plurality of heat exchangers spaced apart from each other and independently controlled are disposed in the electrostatic chuck.

The heat exchanger is a plurality of passages opened in the base to increase or decrease the temperature of the partition in which the heat exchanger is disposed by heating or cooling the fluid in the passage, thereby adjusting the temperature of the corresponding wafer region.

There are several areas on the wafer; there are several partitions on the electrostatic chuck, and several partitions correspond to the positions of several areas.

Correspondingly, a heat exchanger or a heating body or a combination of the two is arranged in different zones; the temperature of each zone is separately adjusted by controlling the respective opening or closing of the heat exchanger or the heating body, and then the respective areas of the wafer are adjusted. temperature.

A plurality of said partitions are arranged on the electrostatic chuck in the same radial direction.

A heating body is provided at least in a partition corresponding to the edge of the wafer.

The heating body is brought closer to the edge of the wafer in the horizontal direction than the position of the heat exchanger in the partition; and, in the vertical direction, the heating body is closer to the wafer than the heat exchanger.

The first and second partitions are radially divided on the electrostatic chuck, and the second partition surrounds the periphery of the first partition and is disposed at the same center; the first partition and the second partition correspond to the central area and the edge area of the wafer.

A heating body is disposed in the dielectric layer of the second partition; a heat exchanger is further disposed in each of the first partition and the second partition, so that the temperatures of the central region and the edge region of the wafer can be separately adjusted.

The heating body is made of a resistance heating element; when the power supply power applied to the resistance heating element is constant, the temperature rise is proportional to the heating time; if the heating time is constant, the temperature increase amplitude is proportional to the power supply power.

The heating body is a heating coil formed by winding a tungsten wire.

Compared with the prior art, the temperature-divisionally adjustable electrostatic chuck of the present invention has the advantages that: the present invention is provided with two sets of heat exchangers, corresponding to the temperature of the wafer center and the edge region; and at least in the corresponding wafer A heating body is arranged in the edge of the edge, and the temperature of the edge of the wafer is lifted flexibly and rapidly by the heating body, and the processing rate of etching, deposition, etc. on the edge of the wafer can be accelerated while the other reaction conditions are constant, thereby offsetting The effect of the original gas distribution on the wafer in the radial direction is uneven, and finally a more uniform processing effect is obtained at the center and the edge of the wafer.

The specific implementation of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1 and FIG. 2, the electrostatic chuck of the present invention comprises a base 12 fixedly disposed at the bottom of the vacuum processing chamber, and a dielectric layer 11 made of a thermally conductive ceramic material disposed on the top of the base 12. . The susceptor 12 is a disk structure having a stepped edge; the dielectric layer 11 has an area equal to or slightly smaller than the area of the wafer 50 placed on the dielectric layer 11. A direct current is applied to the electrode 60 embedded in the dielectric layer 11 to generate an electrostatic charge to hold the wafer 50.

Dividing a plurality of partitions on the electrostatic chuck, for example, may divide the first partition 21 and the second partition 22 in a radial direction, and the second partition 22 surrounds the periphery of the first partition 21 and is disposed at the same center; the first partition 21 and the second The partition 22 corresponds to the central region 51 and the edge region 52 of the wafer 50 on the electrostatic chuck.

In the first and second sections 21 and 22 of the electrostatic chuck, a set of independently controllable chillers 31, 32 are provided. heat The exchanger may be a plurality of passages in the base 12 that increase or decrease the temperature of the respective sections of the electrostatic chuck by heating or cooling the fluid in the passage, thereby enabling adjustment of the temperature of the center and edge regions of the wafer 50, respectively.

A heating body 40 is also disposed inside the dielectric layer 11 of the electrostatic chuck, which may be a plurality of heating coils disposed around the edge of the dielectric layer 11. A heating coil made of a resistance heating element such as a tungsten wire, if the applied power is constant, the magnitude of the temperature rise is proportional to the heating time; if the heating time is constant, the temperature rise is proportional to the power of the power source.

In other embodiments, the number of partitions of the electrostatic chuck may not be limited to two, for example, more partitions may be arranged on the electrostatic chuck along the same radial center. Alternatively, the electrostatic chuck can be partitioned in other ways. The heat exchanger or the heating body or a combination of the two is configured correspondingly in different zones; the zone temperature can be separately adjusted by independently controlling the respective opening or closing of the heat exchanger or the heating body.

Preferably, a heating body is disposed at least in a section of the edge of the corresponding wafer; the heating body is brought closer to the edge of the wafer in the horizontal direction than the position of the heat exchanger in the partition. Since the heating body is closer to the wafer than the heat exchanger in the vertical direction, the temperature rise of the edge region is faster and more flexible.

When the other reaction conditions are constant, the temperature of the edge of the wafer is raised by the heating body, so that the processing rate of the reaction such as etching in the edge region can be accelerated, thereby offsetting the influence of uneven distribution of the original gas in the radial direction of the wafer, and finally A more uniform processing effect is obtained at the center and edge of the wafer.

Although the content of this creation has been made by the preferred embodiment described above It is described in detail, but it should be recognized that the above description should not be construed as limiting the present invention. Various modifications and substitutions of the present invention will become apparent to those skilled in the art of the invention. Accordingly, the scope of the invention should be defined by the appended claims.

11‧‧‧Dielectric layer

12‧‧‧ Pedestal

21‧‧‧First Division

22‧‧‧Second Division

31‧‧‧ heat exchanger

32‧‧‧ heat exchanger

40‧‧‧ heating body

50‧‧‧ wafer

51‧‧‧Central area

52‧‧‧Edge area

60‧‧‧ electrodes

1 is a schematic structural view of a temperature-divisionally adjustable electrostatic chuck according to the present invention; and FIG. 2 is a top view of the electrostatic chuck of the present invention.

11‧‧‧Dielectric layer

12‧‧‧ Pedestal

21‧‧‧First Division

22‧‧‧Second Division

31‧‧‧ heat exchanger

32‧‧‧ heat exchanger

40‧‧‧ heating body

50‧‧‧ wafer

51‧‧‧Central area

52‧‧‧Edge area

60‧‧‧ electrodes

Claims (6)

A temperature-divisionally adjustable electrostatic chuck comprising a base (12) fixedly disposed at the bottom of the vacuum processing chamber, and a dielectric layer (11) made of a thermally conductive ceramic material disposed on the top of the base (12) Applying a direct current to an electrode (60) embedded in the dielectric layer (11) to generate an electrostatic force to hold a wafer (50) placed on the dielectric layer (11), wherein the electrostatic chuck The dielectric layer (11) is further provided with a heating body (40); the heating body (40) is disposed in the dielectric layer (11) above the buried electrode; and the heating body (40) surrounds the The edges of the dielectric layer (11) are arranged to correspond to the edge locations of the wafer (50); the pedestals are provided with a plurality of heat exchangers spaced apart and independently controlled. The temperature-divisionally adjustable electrostatic chuck according to claim 1, wherein the plurality of passages in the base (12) increase or decrease the heat exchanger by heating or cooling the fluid in the passage. The temperature of the zone is adjusted to adjust the temperature of the corresponding wafer (50) region, which is located in the central region and the edge region of the susceptor (12), respectively, and the fluids in the channels of the different regions are independently controlled. The temperature-divisionally adjustable electrostatic chuck according to claim 2, wherein the temperature of each partition is separately adjusted by controlling the opening or closing of the heat exchanger or the heating body, and then the respective regions of the wafer are adjusted. temperature. The temperature-divisionally adjustable electrostatic chuck according to claim 3, wherein the electrostatic chuck has a first partition (21) and a second partition (22) radially partitioned, the second partition (22) Surrounding the periphery of the first partition (21) and being disposed at the same center; the first partition (21) and the second The partition (22) corresponds to the central area (51) and the edge area (52) of the wafer (50); the heating layer (40) is disposed in the dielectric layer (11) of the second partition (22); A heat exchanger is further disposed in each of the first partition (21) and the second partition (22), so that the temperature of the central region and the edge region of the wafer (50) can be separately adjusted. The temperature-divisionally adjustable electrostatic chuck according to claim 1 or 4, wherein the heating body (40) is made of a resistance heating element; when the power applied to the resistance heating element is constant, the temperature rises The high amplitude is proportional to the heating time; if the heating time is constant, the temperature rise is proportional to the power supply. The temperature-divisionally adjustable electrostatic chuck according to claim 5, wherein the heating body (40) is a heating coil formed by winding a tungsten wire.