KR20000061765A - Apparatus for controlling the local temperature of a wafer - Google Patents

Abstract

PURPOSE: A temperature adjusting apparatus is to precisely adjust a surface temperature of a local area of a wafer, thereby preventing the different surface temperature of the local area of the wafer. CONSTITUTION: A temperature adjusting apparatus comprises a thermostatic unit(290) such as a heat exchanger or a chiller. The thermostatic unit is coupled to an electrode(250) through a fluid circulating conduit(292) provided in the electrode. The thermostatic unit circulates a fluid of a desired temperature through the fluid circulating conduit to control a temperature of the electrode. A wafer supporting plate(240) is mounted onto an upper surface of the electrode, and the electrode is heat exchanged with the wafer supporting plate. A thermoelement plate(230) is mounted between an upper end of the wafer supporting plate and a lower surface of the wafer for controlling the temperature of the local area of the wafer. The thermoelement plate is formed with the under end of the safer supporting plate.

Description

Wafer Local Temperature Controller {APPARATUS FOR CONTROLLING THE LOCAL TEMPERATURE OF A WAFER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor processing system, and more particularly, to a local temperature control apparatus for a wafer capable of compensating surface temperature nonuniformity of a wafer generated during a semiconductor processing process.

BACKGROUND OF THE INVENTION A semiconductor device or a semiconductor chip is generally manufactured by processing a wafer formed of silicon using semiconductor equipment. Wafers are typically manufactured into semiconductor devices or semiconductor chips through a series of semiconductor processes such as lithography, chemical or physical vapor deposition, and plasma etching.

The quality of the semiconductor device or semiconductor chip thus manufactured may vary depending on variables such as the quality of the wafer or the way the wafer is processed. One of the important variables in the fabrication of semiconductor devices is the temperature of the wafer surface. That is, the higher the surface temperature of the wafer, the higher quality the semiconductor device can be manufactured.

Surface temperature control of the wafer is performed by adjusting the temperature of the wafer support on which the wafer is mounted. Conventionally, a fluid having a constant temperature, which is made by a chiller or a heat exchanger, is circulated to the electrode, and the wafer support is brought into close contact with the electrode. The temperature of the wafer support was adjusted in such a way as to.

1 shows a conventional semiconductor processing system employing such a temperature control scheme.

As shown in Fig. 1, in the conventional semiconductor processing system, a fluid circulation conduit 50 is provided between the chiller 40 and the electrode 30, and the fluid circulation conduit of the predetermined temperature produced by the chiller 40 is transferred. The temperature of the electrode 30 is controlled by circulating through 50.

The wafer support 20 is mounted on the electrode 30 to exchange heat with the electrode 30, and the wafer 10 is seated on the wafer support 20 so that the wafer support 20 is connected to the wafer support 20. Perform heat exchange. For efficient heat exchange, helium gas is supplied between the wafer 10 and the wafer support 20.

However, in the conventional semiconductor processing system having such a configuration, there is a problem in that even if the temperature of the surface of the wafer 10 is unevenly formed during the semiconductor processing process, it cannot be controlled. The reason why the surface temperature of the wafer 10 is uneven is due to uneven distribution of the plasma, heat loss of the edge region due to contact of the edge of the wafer support 20 with other components, and uneven distribution of helium gas. And nonuniformity of the electrode surface temperature, and in most cases, the actual temperature of the center portion of the wafer 10 and the actual temperature of the edge appear differently.

In particular, in the semiconductor process employing the plasma discharge method, the temperature of the wafer 10 is rapidly increased by an ion reaction having a high energy. When plasma processing is performed in the center of the wafer 10, the temperature of the center is increased. The temperature at the periphery of the wafer is lower than the temperature at the center. Due to the temperature difference between the center and the periphery, the periphery of the wafer 10 becomes unsuitable for the manufacture of the semiconductor chip, which is unnecessary in view of the current trend of the large diameter of the wafer and the miniaturization of the semiconductor chip. Can cause waste.

In addition, when a temperature difference occurs on the surface of the wafer 10, a critical dimension difference between the center portion and the peripheral portion may occur, as well as a difference in the etch rate, thereby affecting the product quality. .

In order to overcome the above problems, various apparatuses have been developed to detect the temperature of the center and peripheral regions of the wafer during the semiconductor processing process and to uniformly control the temperature of the regions using thermoelectric elements. One example of such devices is disclosed in US Pat. No. 5,740,016. 2 and 3 show an apparatus for uniformly controlling the temperature of the wafer disclosed in the above-mentioned US patent.

As shown in FIG. 2, the semiconductor processing system 100 disclosed in the patent includes a chamber 130 and an electrode 110 disposed in the chamber 130. The wafer 120 is seated on the electrode 110, and an insulating layer 160 is provided on the bottom of the electrode 110. In addition, a plurality of thermoelectric elements 140 are mounted on the bottom surface of the insulating layer 160.

As shown in FIG. 3, the thermoelectric elements 140 have a circular loop shape and are disposed at predetermined intervals from a center of the electrode 110 to an outer edge thereof. The thermoelectric elements 140 are in contact with a heat sink 170 and are connected to the current supply device 180 by a plurality of wires 142 and 144. In addition, a sensor 190 for detecting the surface temperature of the wafer 120 is installed outside the chamber 100. The sensor 190 and the current supply device 180 is controlled to be operated by the controller 195.

During the semiconductor processing process, the sensor 190 detects the surface temperature of the wafer 120 and transmits it to the controller 195. The controller 195 generates a predetermined current based on the transmitted temperature data. The current supply device 180 is operated to be applied to the thermoelectric elements 140. At this time, when the temperature of the peripheral portion of the wafer 120 is lower than the temperature of the central portion, the temperature of the thermoelectric element 140 disposed on the peripheral portion side of the wafer 120 is increased. The surface temperature of the wafer 120 is maintained uniformly by increasing the temperature of the device 140.

However, since the semiconductor processing system 100 is configured to raise or lower the temperature of the center and the periphery of the wafer 120 at a constant level, it is impossible to uniformly adjust the temperature when a temperature difference occurs in the unit area within the center or the periphery. The disadvantage is that. In other words, even when a temperature difference occurs in the A zone and the B zone of the periphery, the surface temperature of the wafer 120 is uniform because the same temperature is applied to the A zone and the B zone by the circular thermoelectric element 140. There is a problem that is not maintained.

In addition, the system 100 uses a heat-sensitive infrared sensor 190 as a means for detecting the surface temperature of the wafer 120. In the plasma etching process, since the temperature in the chamber 130 maintains a high temperature state, There is a problem that the surface temperature of the wafer 120 cannot be accurately detected by the sensor 190.

In addition, since the system 100 controls the temperature of the entire wafer 120 using the thermoelectric elements 140, when the temperature of the wafer 120 is raised to a high temperature, the electrical device is overloaded. Using the thermoelectric elements 140 is also difficult to perform precise temperature control of units below the decimal point.

The present invention has been made to overcome the problems of the prior art, the object of the present invention is to solve the local temperature imbalance of the wafer surface generated during the semiconductor processing process as well as to precisely control the surface temperature of the wafer locally It is to provide a local temperature control device of a wafer.

1 illustrates a conventional semiconductor processing system.

2 illustrates another conventional semiconductor processing system.

3 is a plan view of the thermoelectric element shown in FIG.

4 is a cross-sectional view of a semiconductor processing system having a local temperature controller according to an embodiment of the present invention.

FIG. 5 is a plan view of the thermoelectric plate shown in FIG. 4.

6 is a view illustrating a state in which wires connected to a thermoelectric element are integrated in a cable.

<Explanation of symbols for main parts of drawing>

200: semiconductor processing system 210: wafer

220: insulating layer 230: thermoelectric plate

240: wafer support 250: electrode

270: current supply device 280: controller

290: constant temperature holding device 292: fluid circulation conduit

In order to achieve the above object, the present invention, in the temperature control device for controlling the local temperature of the wafer used in the semiconductor processing process, the bottom surface of the wafer is in contact with the wafer to perform heat exchange with the wafer, corresponding to the size of the wafer It has a size, and the surface is provided with a thermoelectric plate on which a plurality of lattice-type thermoelectric elements are radially and evenly mounted, and an electrical signal applying means for individually applying electrical signals to the plurality of thermoelectric elements. It provides a local temperature control of the wafer.

The electric signal applying means individually applies an electric signal to each of the thermoelements disposed on the thermoelectric element plate. The electric signal applying means has wires respectively connected to the plurality of thermoelectric elements, the wires receive current from a current supply device, and the current supply device is controlled to be operated by a controller. The wires are integrally integrated by a cable.

By maintaining a uniform surface temperature of the wafer to enable the production of high-quality semiconductor devices, as well as to allow the peripheral portion of the wafer to be used in the production of semiconductor devices, it is possible to reduce the manufacturing cost required for semiconductor device production. In addition, the temperature of the wafer can be locally controlled as needed, and the surface temperature of the wafer can be controlled very precisely.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 shows a semiconductor processing system 200 with a local temperature control device in accordance with one embodiment of the present invention. As shown, the semiconductor processing system 200 includes a constant temperature holding device 290, collectively referred to as a heat exchanger or chiller. The thermostat 290 is connected to the electrode 250 via a fluid circulation conduit 292. The fluid circulation conduit 292 is mounted inside the electrode 250, and the constant temperature maintaining device 290 circulates a fluid having a predetermined temperature through the fluid circulation conduit 292 and thus the electrode 250. To control the temperature. The temperature maintaining apparatus 290 is controlled by the controller 280.

The wafer supporter 240 that performs heat exchange with the electrode 250 is mounted on the upper surface of the electrode 250. In general, the wafer support 240 is made of a material capable of improving thermal conductivity, such as aluminum. The wafer support 240 is formed in two stages, and the wafer 210 is seated at the top 242 to exchange heat with the top 242 of the wafer support 240. In addition, the lower end 244 of the wafer support 240 is formed somewhat larger than the upper end 242, and is fixedly coupled to the upper surface of the electrode 250 by fixing means such as a screw 245. It is possible to efficiently transfer heat from the 250).

Between the top 242 of the wafer support 240 and the bottom of the wafer 210, a thermoelectric plate 230 for controlling a local temperature of the surface of the wafer 210 is mounted. The thermoelectric element plate 230 is preferably inserted and molded into the upper end 242 of the wafer support 240, but may be fixedly attached to the upper end 242 using fixing means such as an adhesive. If the constant temperature holding device 290 functions to provide the basic temperature required for the wafer 210, the thermoelectric plate 230 may have a minute temperature difference occurring on the surface of the wafer 210 during the semiconductor processing process. To compensate.

As shown in FIG. 5, the thermoelectric element plate 230 has a shape and size corresponding to that of the wafer 210, and the surface thereof is individually electrically controlled to finely adjust the temperature of the surface of the wafer 210. A plurality of lattice type thermoelectric elements are evenly mounted radially. The thermoelectric element is a plurality of first thermoelectric elements 232 arranged in a circle at a predetermined interval at the outermost portion of the thermoelectric element plate 230, a predetermined distance radially inward from the first thermoelectric elements 232. A plurality of second thermoelectric elements 234 spaced apart from each other and arranged in a circle at predetermined intervals and a circular third thermoelectric element 236 disposed in the center of the thermoelectric element plate 230 are included.

By forming the first to third thermoelectric elements 232, 234, and 236 evenly in a lattice shape, the top, bottom, left and right sides of the wafer 210 as well as the center portion and the edge portion EDGE of the wafer 210 are formed. It is possible to individually control the temperature of the local zone of the wafer 210.

That is, since the temperatures of “a” and “b” of the first thermoelectric elements 232 disposed on the edge of the thermoelectric element plate 230 can be controlled, respectively, the contact with “a” and “b” is performed. Even when the temperatures of the wafer 210 regions are formed differently, their temperatures can be controlled to the desired temperatures. This means that even if the temperature is formed differently in the unit area of the edge or center of the wafer 210, it can be preferably matched, and on the other hand, the individual unit areas constituting the center and the periphery are required. This means that it can be maintained at different temperatures.

Referring to FIG. 4 again, an insulating layer 220 is provided on the upper surface of the thermoelectric element plate 230. The insulating layer 220 serves to prevent the thermoelectric elements 232, 234, and 236 from being damaged by plasma or the like during the semiconductor processing process. The insulating layer 220 is preferably formed of an aluminum oxide film, but other materials may be used as long as the insulating layer 220 has a condition of protecting the first to third thermoelectric elements 232, 234, and 236 from plasma and maintaining thermal conductivity. have.

In addition, helium gas is supplied between the insulating layer 220 and the bottom of the wafer 210 so that heat transfer to the bottom of the wafer 210 can be effectively performed. In order to smoothly supply helium gas, a helium guide groove (not shown) is formed on an upper surface of the insulating layer 220, and the wafer support 240 and the electrode 250 guide helium gas toward the helium guide groove. The first to third helium guide holes 238, 285, and 286 are formed in communication with each other.

The first to third thermoelectric elements 232, 234, and 236 may be integrally formed on the thermoelectric element plate 230 by an insert molding method. Here, insert molding means that the first to third thermoelectric elements 232, 234, and 236 are arranged in a predetermined pattern, a mold is installed at an outer side thereof, and a molding metal is injected into the mold to thermoelectric plate 230. ) Means a process for manufacturing. This insert molding ensures a tight fit between the parts.

In addition, the local temperature control device according to an embodiment of the present invention includes an electrical signal applying device for applying an electrical signal to the thermoelectric elements individually. The electrical signal applying device includes a plurality of wires 237, a current supply device 270, a controller 280, and a cable 295.

Referring to FIG. 6, one end of the first to third thermoelectric elements 232, 234, and 236 and the plurality of wires 237 are connected, respectively, and the other end of the plurality of wires 237 is a current supply device. 270 is connected. The current supply device 270 is controlled by an operation signal generated by the controller 280 and is connected to a power supply to receive an electric current to supply an electrical signal for supplying the first to third thermoelectric elements 232, 234, and 236. Create Through-holes 294 and 296 are formed in communication with the wafer support 240 and the electrode 250 so that the wires 237 may be connected to the current supply device 270. In addition, a cable 295 for integrally integrating the wires 237 is disposed in the through holes 294 and 296 to prevent a decrease in the efficiency of the device due to the insufficiency of the wires 237.

The semiconductor processing system 200 equipped with the local temperature control device according to the present invention having the configuration as described above operates as follows.

First, when a semiconductor processing process is started, the controller 280 applies an operation start signal to the constant temperature maintaining apparatus 290. Accordingly, the constant temperature maintaining apparatus 290 circulates a fluid having a predetermined temperature through the fluid circulation conduit 292, and the electrode 250 is heated to a predetermined temperature by the circulation of the fluid.

The heat generated by the electrode 250 is transferred to the bottom surface of the wafer 210 through the wafer support 240 coupled to the top surface of the electrode 250, so that the wafer 210 has a predetermined temperature.

At this time, helium gas is supplied between the bottom surface of the wafer 210 and the upper end 242 of the wafer supporter 240 through the first to third helium guide holes 238, 285, and 286, wherein the helium gas is the wafer. By filling the gap that may be formed between the bottom of the 210 and the top 242 of the wafer support 240, it prevents heat loss and improves the heat transfer efficiency.

Subsequently, the controller 280 applies an operation signal to the current supply device 270, and the current supply device 270 includes first to third thermoelectric elements 232, 234, and 236 mounted on the thermoelectric plate 230. To generate an electrical signal to selectively supply current. This is to compensate for the unbalance of the surface temperature of the wafer 210. As the heat loss is generated at the edge of the wafer support 240 due to the contact between the wafer support 240 and the peripheral components, the wafer 210 To compensate for the difference in temperature occurs in the center and the peripheral portion of the, and also to compensate for the different temperature of the surface of the wafer 210 due to the nonuniformity or concentration of the plasma.

The current supply to the first to third thermoelectric elements 232, 234, and 236 is performed according to an algorithm preset to the controller 280. That is, the temperature difference of the surface of the wafer 210 may be determined by analyzing a deposition formed on the wafer 210 or a difference in the etching rate of the surface of the wafer 210 during a measurement process, and based on the analyzed data. The temperature trend of the local area 210 is input to the controller 280 using a predetermined algorithm. Accordingly, the controller 280 selectively heats the first to third thermoelectric elements 232, 234, and 236 corresponding to the surface of the wafer 210 where the temperature nonuniformity occurs during the semiconductor processing process. The cooling is to compensate for the unbalance of the temperature generated in the local unit of the wafer 210.

The temperature compensation operation by the first to third thermoelectric elements 232, 234, and 236 is performed in a very fine temperature range, in order to prevent overload of the electric device and to enable precise temperature compensation. . Therefore, as described above, the basic temperature for the wafer 210 is provided by the constant temperature maintaining device 290, and the first to third thermoelectric elements 232, 234, and 236 are provided by the controller 280. The control is performed to finely adjust the temperature of the local region of the wafer 210.

Therefore, while the wafer 210 is maintained at a uniform temperature, a semiconductor process such as chemical vapor deposition, physical vapor deposition, or plasma etching is performed, and accordingly, a high quality semiconductor device can be produced, as well as a peripheral portion of the wafer 210. Alternatively, the edges are not discarded and can be used for the production of semiconductor devices.

Subsequently, when the semiconductor processing process is completed, the controller 280 stops the operation of the constant temperature maintaining device 290 and the current supply device 270 and has a rest period for the next operation.

As described above, according to the present invention, since the surface temperature of the wafer is maintained uniformly, it is possible to produce a high-quality semiconductor device, as well as the manufacturing required for semiconductor device production because the peripheral portion of the wafer can be used for the semiconductor device production. You can reduce costs.

In addition, the present invention may control the surface temperature of the wafer differently as needed, and has the advantage of precisely controlling the surface temperature of the wafer.

The present invention is not limited to the above embodiments, and various improvements and modifications are possible within the scope of the technical idea of the present invention, and those skilled in the art will recognize that such improvements or modifications also belong to the present invention.

Claims (4)

A plurality of lattice type thermoelectric elements contacting the bottom surface of the wafer to exchange heat with the wafer, having a shape and size corresponding to that of the wafer, and individually receiving electrical signals on the surface of the wafer to finely adjust the temperature of the wafer surface A thermoelectric plate on which is radially evenly mounted; And And an electric signal applying means for independently applying an electric signal to the plurality of thermoelectric elements. The apparatus of claim 1, wherein an insulating layer is provided on an upper surface of the thermoelectric element plate to prevent the thermoelectric element from being damaged during a semiconductor processing process. The wafer of claim 1 or 2, wherein the thermoelectric elements are insert molded integrally with the thermoelectric plate, and the thermoelectric plate is insert molded on the upper surface of the wafer support on which the wafer is seated. Thermostat. The apparatus of claim 1, wherein the electrical signal applying means comprises: a wire connected at one end thereof to the plurality of thermal elements, a current supply device connected to the other end of the wire and connected to a power source to generate the electrical signal; And a controller for applying an operation signal for generating said electrical signal to said current supply device, and a cable for integrally integrating said wires.