JPH02143440A - Wafer chuck of semiconductor wafer processing equipment - Google Patents

Abstract

PURPOSE:To enable precise temperature control of a wafer with excellent thermal conduction efficiency and response by controlling refrigerant flowing in a stage holder retaining a wafer, based on the detected value of a temperature sensor abutting on the rear of the semiconductor wafer. CONSTITUTION:When a chuck unit 8 is attached to a stage holder 9, a refrigerant feeding line 25 and a jacket 10f for refrigerant use formed on a state 10 are communicated through a refrigerant channel 9b and a refrigerant feeding hole 10g of the holder 9. When a water feeding pump 26 is operated, water as refrigerant flows in the path shown by an arrow; the water flowing in the jacket of the stage 10 cools an electrostatic chuck 11 via a lower flange 10, thereby cooling a wafer 15 being attached and held by the chuck 11. On the other hand, when the wafer is attracted and held by the chuck 11 in a film formation process, a temperature detection value from a sensor 19 abutting on the rear of the wafer 15 is input to a controller 29, which controls a cooler 27 and a flow rate control valve 28, based on the deviation from a set temperature value, in the manner in which the temperature of the wafer 15 is kept at a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wafer chuck installed in a semiconductor wafer processing apparatus to suction and hold a semiconductor wafer carried into the chamber at a predetermined position.

[Conventional technology]

First, the semiconductor wafer processing equipment mentioned above (plasma CVD
Figure 3 shows an overview of the single wafer processing equipment.

In the figure, 1 is the vacuum chamber of the process reaction chamber, 2 is the plasma generation chamber provided at the bottom of the vacuum chamber 1, 3 is the vacuum pump, and 4.5 is the loading device connected to the vacuum chamber 1 via the vacuum gate valve 6. A lock chamber on the unloading side, 7 is a wafer transfer robot that moves within the lock chamber 4.5, and 8 is a wafer chuck installed in the upper part of the vacuum chamber 1.

Here, the wafer chuck 8 includes a stage holder 9 attached through the wall of the vacuum chamber 1, and a chuck unit that is detachably attached to the tip of the stage holder 9 by coupling an electrostatic chuck 11 to the chuck stage 10. It consists of In addition, the stage holder 9 is installed outdoors using the lifting drive unit 12.
Further, the penetrating portion of the vacuum chamber 1 is sealed by a bellows 13. Note that 14 is a power supply device that applies voltage to the electrostatic chuck 11.

The procedure of wafer processing by such a semiconductor wafer processing apparatus is well known, and includes an unprocessed semiconductor wafer 15 carried into the vacuum chamber 1 by the operation of the transfer robot 7 in the loading-side lock chamber 4, and transferred to the wafer chuck 8. , the electrostatic chuck 11 attracts and holds the zero, and in this state, plasma
A film formation process using VD is performed. After the processing is completed, the transfer robot 7 in the unloading lock chamber 5 is operated to pick up the processed wafer from the wafer chassis 8 and carry it out of the room.

In addition, with the recent increase in the size of semiconductor wafers,
For example, many types of semiconductor wafers of different sizes, such as 4 inches, 5 inches, and 6 inches, are often processed in a small loft, and for this purpose, chuck units with diameters corresponding to each wafer size are prepared as outlined above. Each time the loft is changed, the chuck unit is replaced with a chuck unit that matches the wafer size of the semiconductor wafer to be processed.

By the way, when performing the above-described plasma CVD film forming process on a semiconductor wafer, temperature control of the semiconductor wafer is extremely important. In other words, in order to generate a uniform film on the surface of a semiconductor wafer, there is an optimal processing temperature condition corresponding to the type of film formation, and it is necessary to maintain the semiconductor wafer at a specified temperature during the film formation process. It is.

On the other hand, when a semiconductor wafer is subjected to a film forming process in a plasma atmosphere, the wafer surface is heated, and the thermal energy is approximately I
This also applies to W/c-, and heat generated by voltage application to the electrostatic chuck is also added. Therefore, if this state is left as it is, the wafer temperature will rise above the specified temperature. Therefore, in order to suppress the excessive temperature rise of the semiconductor wafer during the film forming process, conventionally a cooling jacket using water or the like as a coolant is provided around the outer periphery of the stage holder 9 shown in FIG. Semiconductor wafer I5 is held by electrostatic chuck 11 with forced circulation.
A method of indirectly cooling is generally adopted.

[Problems to be Solved by the Invention] By the way, the conventional cooling method described above has the following drawbacks. That is, since the thick chuck stage 10 is interposed between the stage holder 9 equipped with a cooling jacket and the electrostatic chuck 11, the heat transfer between the coolant and the semiconductor wafer I5 is poor.

The cooling response is low, making it impossible to efficiently cool the semiconductor wafer, and the temperature of the refrigerant flowing into the cooling jacket is controlled to a certain degree by installing a cooler in the system in the conventional method. Cooling control is not performed in accordance with the temperature of the semiconductor wafer itself.

Therefore, with conventional cooling methods, it is not possible to achieve highly accurate and detailed temperature control in response to changes in the type of film formation in the process and the size of the semiconductor wafer. This is a major issue that must be resolved in order to move forward.

The present invention has been made in consideration of the above points, and takes into consideration the workability of replacing wafer chucks due to changes in the size of semiconductor wafers, and provides a method for handling semiconductor wafers with good heat transfer efficiency and responsiveness, and at a specified temperature. An object of the present invention is to provide a wafer chuck equipped with a cooling means that allows highly accurate temperature control.

[Means to solve the problem]

In order to solve the above problems, in the wafer chunk of the present invention, the coolant i! an electrostatic chuck cooling jacket formed on the chuck stage so as to communicate with a coolant supply line outside the reaction chamber via a line;
A temperature sensor installed in the chuck unit that detects the wafer temperature by coming into contact with the back side of the semiconductor wafer held by the electrostatic chuck, and control of the refrigerant system that manages the temperature of the semiconductor wafer based on the detected value of the temperature sensor. and means.

[Effect]

In the above configuration, the jacket for cooling the electrostatic chuck provided on the chuck stage is defined by a bellows or the like on the back area of the flange that is closely coupled to the electrostatic chuck, and when the chuck unit is attached to the stage holder, A coolant sent from an external coolant supply line via a coolant passage in the stage holder flows through the jacket to cool the electrostatic chuck and the semiconductor wafer held by the electrostatic chuck. Further, a temperature sensor for detecting wafer temperature is, for example, a thermocouple, and is incorporated into the wafer unit so as to penetrate through the center of the electrostatic chuck and come into contact with the surface of the semiconductor wafer from behind. Further, the refrigerant system control means includes a controller including a cooler installed in an external refrigerant supply line, a temperature regulator for the cooler, a flow 1 regulator for the refrigerant flowing through the refrigerant supply line, and the like, The detected value of the sensor is given to the controller and compared with the specified set temperature, and based on the deviation, the cooling capacity of the cooler and the refrigerant 2 are adjusted.
Feedback control is performed so that the wafer temperature of the semiconductor wafer during processing is maintained at a specified temperature by adjusting the amount of a.

As a result of the above, the coolant flows within the jacket of the chuck stage that is in close contact with the electrostatic chuck, so that high heat conductivity and thermal responsiveness can be obtained between the coolant and the semiconductor wafer. Furthermore, by directly detecting the wafer temperature of semiconductor wafers and controlling the coolant system based on this, the wafer temperature can be maintained at a predetermined temperature with high precision, regardless of changes in wafer size or changes in process conditions. can be maintained. Further, the aforementioned electrostatic chuck cooling jacket is provided for each chuck unit of various sizes, and when the chuck unit is mounted on the stage holder, the coolant passage is connected at the same time.

〔Example〕

FIG. 1 is a cross-sectional view of a wafer chuck according to an embodiment of the present invention, and FIG. 2 is a plan view of a connector section installed in the center of the chuck stage in FIG. 1.

In the figure, the stage holder 9 of the wafer chuck 8 is
It becomes a cylindrical shaft with a brim-like flange 9a at the lower end,
A jacket 9c is provided on its outer periphery to form a refrigerant inlet and outlet passage 9b. On the other hand, the electrostatic chuck 11 is in close contact with the chuck stage 10 vertically to form a chuck unit.

Here, the chuck stage lO includes an upper flange loa that is coupled to the stage holder 9, a lower flange lOb that is tightly coupled to the electrostatic chuck IT, and an upper and lower flange lo.
a, central hollow slide bearing 10c fitted in 10b;
It consists of double inner and outer metal bellows 10d and 10e that surround the hollow slide bearing 10c and are interposed between the upper and lower flanges 10a and the job, where the upper and lower flanges l
A jacket 10f for cooling the electrostatic chuck is defined in the space surrounded by the bellows 10d and 10e.
A refrigerant guide hole 10g that communicates with the refrigerant passage 9b on the stage holder side is open. Note that 16 is a fastening bolt for fixing the chuck stage IO to the stage holder 9;
17 is a positioning pin, and 18 is an O-ring for sealing.

Further, two energizing plugs llb pulled out from the electrode 11a of the electrostatic chuck 11 are mounted on the boring pedestal provided inside the hollow slide bearing 10c, and the electrostatic chuck 11
Temperature sensors 19 for detecting the wafer temperature of the semiconductor wafer 15 held by suction are provided in an arrangement as shown in FIG. In FIG. 2, reference numeral 20 denotes a fastening bolt that connects the chuck stage 10 and the electrostatic chuck 11. here,
The temperature sensor 19 is a thermocouple, and the electrostatic chuck 1
1 in a loosely fitted manner, and is attached to and biased by a metal bellows 21 which also serves as a vacuum seal so that the temperature sensing end at the tip protrudes slightly from the chuck surface. In addition, in the illustrated example, the temperature of three parts of the semiconductor wafer 15 is detected by two parts.
The temperature sensor 19 is equipped with a temperature sensor 19, but basically it may be installed in one location.On the other hand, electricity is supplied through the socket holder 22 in the shaft of the stage holder 9, which is opposite to the above-mentioned energizing plug llb and the temperature sensor 19. Socket 23. A temperature sensor socket 24 is attached.

Furthermore, the refrigerant passage 9 in the stage holder 9 described above
An external refrigerant supply pipe 25 is connected between the inlet and outlet of b. This refrigerant supply line 25 is, for example, a water circulation line using water as a refrigerant, and a water pump 26. Cooler 27. and a flow rate control valve 28. The cooler 27 is an air-cooled or water-cooled heat exchanger, and its cooling capacity is adjusted and controlled by a command from a controller 29 including a temperature regulator. Also,
Similarly, the flow rate control valve 28 also controls the refrigerant flow rate based on a command from the controller 29.

Next, the cooling effect of the wafer chuck with the above configuration will be explained. First, when the chuck unit is attached to the stage holder 9, between the external coolant supply line 25 and the cooling jacket 10f formed on the chuck stage IO, the coolant passage 9b of the stage holder 9 and the coolant guide hole Log
communicated via. When the water pump 26 is operated, water as a refrigerant flows through the path shown by the arrow, and during the flow process, the water flowing inside the jacket of the chuck stage 10 passes through the lower flange 10b of the chuck stage to the electrostatic chuck. The electrostatic chuck 11 is cooled to remove heat generated due to voltage application to the electrostatic chuck 11 and heat generated during processing of the semiconductor wafer 15 held by the electrostatic chuck 11.

On the other hand, in the semiconductor wafer film-forming process, semiconductor wafer 1
5 is suctioned and held by the electrostatic chuck 11 of the wafer chuck 8 , the temperature detection end of the temperature sensor 19 comes into contact with the back surface of the semiconductor wafer 15 . Then, the temperature detection value of the semiconductor wafer I5 detected by the temperature sensor 19 during the film forming process is input to the controller 29, where it is compared with a set temperature specified in advance as the film forming process condition, and based on the deviation. A cooler 27 installed in the refrigerant supply line 25. Feedback control is performed by adjusting the flow rate control valve 28 so that the temperature of the semiconductor wafer 15 is maintained at a specified temperature. That is,
If the temperature of the semiconductor wafer 15 is higher than the set temperature, the cooling capacity of the cooler 27 and the coolant flow rate are increased. Conversely, if the temperature falls below the set temperature, the cooling capacity of the cooler is weakened and the refrigerant flow rate is controlled to be reduced.

In addition, a jacket 10f for cooling the electrostatic chuck provided on the chuck stage 10 is connected to a bellows rod 10e between the upper and lower flanges 10a and 1obO as in the illustrated embodiment.
By interposing and configuring the chuck stage 10
With the electrostatic chuck 11 coupled to the lower flange lOb, which serves as a heat transfer member for the refrigerant, it is possible to bring the lower flange lOb into close contact with the electrostatic chuck 11.

Note that even if the chuck unit is replaced with one having a different diameter due to a change in the size of the semiconductor wafer 15, the cooling operation is performed in exactly the same way. In this case, the hollow slide bearing foe, the ifi degree sensor 19, etc. incorporated in the chuck stage 10 in the illustrated embodiment can also be used as common parts for chuck units of various sizes.

〔Effect of the invention〕

Since the wafer chuck according to the present invention is configured as described above, it has the following effects.

(1) During process processing, the cooling operation performed with the semiconductor wafer adsorbed and held on the wafer chuck allows coolant to flow through the jacket formed on the chuck stage that is tightly coupled to the NT chuck, so that the stage holder Compared to a cooling method in which a refrigerant is passed through a cooling jacket, a high heat transfer property between the refrigerant and the electrostatic chuck or the semiconductor wafer, and therefore a high cooling effect can be obtained.

(2) Coupled with the high heat conductivity mentioned in the previous section, the temperature of the semiconductor wafer is directly detected by a temperature sensor to control the coolant system, so it is not affected by changes in wafer size or changes in processing conditions. Appropriate temperature control can be achieved to maintain semiconductor wafers at a specified temperature with high responsiveness and precision without any problems.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the configuration of a wafer chuck according to an embodiment of the present invention, FIG. 2 is a plan view of a connector section incorporated in the center of the chuck stage in FIG. 1, and FIG. 3 is an overall schematic diagram of a semiconductor wafer processing apparatus. In a certain figure 0, 1: vacuum chamber of process reaction chamber, 8: wafer chuck, 9: stage holder, 9b: coolant passage, 10: chuck stage, 10f: jacket, 11: electrostatic chuck, 15: semiconductor wafer, 19 : temperature sensor, 25: refrigerant supply line, 27; cooler, 29: controller. H Figure 2 Figure 3

Claims (1)

[Claims] 1) A wafer chuck installed in a process reaction chamber to hold a semiconductor wafer carried into the chamber, in which a chuck unit in which an electrostatic chuck is coupled to a chuck stage is removably attached to a stage holder installed on the reaction chamber side. In an electrostatic chuck cooling jacket, an electrostatic chuck cooling jacket formed on the chuck stage is connected to a coolant supply line outside the reaction chamber via a coolant passage in the stage holder, and the back side of the semiconductor wafer attracted to the electrostatic chuck is brought into contact with the electrostatic chuck cooling jacket. A semiconductor wafer processing apparatus comprising: a temperature sensor installed in a chuck unit for detecting the wafer temperature; and a refrigerant system control means for controlling the temperature of the semiconductor wafer based on the detected value of the temperature sensor. wafer chuck.