JP3948773B2 - Wafer displacement detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wafer shift detection device, and more particularly to a wafer shift detection device useful for etching, sputtering, and CVD.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, vacuum processing apparatuses that place a wafer stage in a vacuum vessel and place the wafer on the wafer stage for rotation processing are used in various fields such as etching, sputtering, and CVD. By the way, in such a vacuum processing apparatus, since the wafer rotates at a high speed, it is necessary to confirm that the wafer is installed at a predetermined place before starting the rotation. That is, the state in which the wafer 3 is placed on the step 2 of the wafer stage 1 disposed in the vacuum vessel (not shown) as shown in FIG. 2 is a normal state, but the wafer 3 as shown in FIG. It is necessary to confirm whether or not is shifted from the step 2 to an abnormal state. In the figure, reference numeral 4 denotes a rotating body that fits with the wafer stage 1, and reference numeral 5 denotes a heater.
[0003]
[Problems to be solved by the invention]
By the way, when the wafer 3 deviates from the step 2 as shown in FIG. 3, the wafer 3 jumps out of the wafer stage 1 due to the centrifugal force at the time of rotation, and the wafer 3 collides with the inner wall of the vacuum vessel and the wafer is damaged. There was a problem. Conventionally, there has been no means for confirming whether the wafer is deviated from the level difference of the wafer stage.
[0004]
The present invention has been made in consideration of such circumstances, and by providing a thermometer for measuring the temperature of the wafer, it is possible to accurately grasp the presence or absence of deviation of the wafer from the wafer stage and prevent wafer damage. An object is to provide a detection device.
[0005]
[Means for Solving the Problems]
The present invention includes a vacuum container in which a wafer is disposed, a wafer stage disposed in the vacuum container and having a step for dropping the wafer, a rotating mechanism for rotating the wafer stage, and heating the wafer A heater for measuring the temperature of the wafer, and a calculator electrically connected to the thermometer and discriminating a wafer deviation based on a temperature distribution of the wafer obtained by the thermometer. This is a wafer deviation detecting device.
[0006]
In the present invention, an example of the thermometer is a radiation thermometer that detects the temperature of the surface of the wafer. This radiation thermometer is composed of a radiation thermometer body, a thermometer sensor head, and an optical fiber connecting the radiation thermometer body and the thermometer sensor head. The thermometer sensor head is preferably provided so as to be located immediately above the peripheral edge of the wafer. The thermometer sensor head preferably measures the peripheral edge of the wafer, which is susceptible to temperature effects due to wafer misalignment, and one or more thermometer sensor heads are provided so as to be positioned directly above the peripheral edge of the wafer.
[0007]
(Function)
The present invention discriminates the deviation of the wafer from the temperature distribution in the circumferential direction of the wafer using a thermometer. In other words, when the wafer is correctly on the step of the wafer holder, the temperature distribution in the circumferential direction of the wafer has a substantially constant value. However, when the wafer moves out of the step of the wafer holder and becomes in the state as shown in FIG. 3, the temperature of the wafer is low at the portion where the wafer has traveled, and conversely at this position 180 ° shifted from the circumferential direction. The wafer temperature increases. Therefore, in the case of this abnormality, a wafer that rotates at a low speed has characteristics such that a high temperature and a low temperature alternately and periodically, as shown by a curve (b) in FIG. As described above, the wafer deviation can be accurately grasped based on the temperature distribution of the wafer measured by the thermometer.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIG.
Reference numeral 11 in the figure denotes a SUS vacuum container having an Al lid 12 attached to the upper part. The lid 12 has an opening 12a at a portion located immediately above a step of a wafer holder, which will be described later, and a glass window 12b on the opening 12a. In the vacuum vessel 11, a wafer holder 14 on which the wafer 13 is placed and a rotating body 15 that forms a cavity together with the wafer holder 14 are arranged. The wafer holder 14 is provided with a step 16 for dropping and holding the wafer 13. The step 16 is provided with some play for the convenience of wafer transfer.
[0009]
A heater 17 for heating the wafer 13 is disposed in the cavity. The lower part of the rotating body 15 is connected to a rotation introducing mechanism 18. A thermometer sensor head 19 for measuring the surface temperature of the wafer 13 is disposed outside the vacuum vessel 11 located immediately above the step 16 of the wafer holder 14. A radiation thermometer main body 21 is connected to the thermometer sensor head 19 via an optical fiber 20. Here, the thermometer sensor head 19, the optical fiber 20 and the radiation thermometer main body 21 constitute a radiation thermometer. The radiation thermometer main body 21 is electrically connected to a calculator 22 that discriminates the deviation of the wafer 13 based on the measured temperature distribution of the wafer 13. The arithmetic unit 22 is electrically connected to a control panel 23 to which a signal indicating whether or not the wafer 13 is shifted from the arithmetic unit 22 is sent.
[0010]
In the apparatus having such a configuration, first, the wafer 13 is rotated at a low speed of, for example, about 30 rpm. When the temperature distribution in the circumferential direction of the wafer 13 by the radiation thermometer becomes substantially constant as shown by the curve (a) in FIG. 4 during this low-speed rotation, the analog temperature is transferred from the radiation thermometer main body 21 to the calculator 22. A signal is sent through the analog signal line 24, a signal of “no wafer misalignment” is sent from the computing unit 22 to the control panel 23, the wafer 13 is rotated at a high speed of about 3000 rpm, for example, and processing such as etching is performed.
[0011]
On the other hand, when the temperature distribution in the circumferential direction of the wafer 13 by the radiation thermometer changes greatly as shown by the curve (b) in FIG. 4 during low-speed rotation, the temperature is transferred from the radiation thermometer body 21 to the calculator 22. An analog signal is sent through the analog signal line 24, a signal indicating “wafer misalignment” is sent from the computing unit 22 to the control panel 23, and after the misalignment of the wafer 13, the processing such as etching is performed at high speed.
[0012]
According to the above embodiment, the thermometer sensor head 19 for measuring the surface temperature of the wafer 13 is arranged outside the vacuum vessel 11 positioned just above the step 16 of the wafer holder 14, and this thermometer sensor head 19 is further arranged. Since the computing unit 22 for discriminating the deviation of the wafer 13 is electrically connected based on the temperature distribution of the wafer 13 measured in step 1, the wafer 13 is normally mounted on the step 16 of the wafer holder 14. It can be easily determined whether or not there is. That is, when the wafer 13 is normally on the step 16 of the wafer holder 14, as shown by the curve (a) in FIG. 4, the temperature distribution in which the surface temperature in the circumferential direction of the wafer becomes almost constant is shown. When the vehicle is not on the vehicle, a temperature distribution is shown in which the temperature changes periodically at a low rotational speed as shown by the curve (b) in FIG. Therefore, from the temperature distribution of FIG. 4, it can be reliably determined whether or not the wafer 13 is normally on the step 16 of the wafer holder 14, and the wafer 13 protrudes from the step 16 and collides with the inner wall of the vacuum vessel and breaks. Can be avoided.
[0013]
【The invention's effect】
As described above in detail, according to the present invention, by providing a thermometer for measuring the temperature of a wafer, it is possible to provide a wafer deviation detecting device capable of accurately grasping the deviation from the wafer stage of the wafer and preventing the wafer from being damaged.
[Brief description of the drawings]
FIG. 1 is an overall view of a wafer shift detection apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram when the wafer is normally on the step of the wafer holder.
FIG. 3 is an explanatory diagram in the case of an abnormal state in which the wafer protrudes from the level difference of the wafer holder.
FIG. 4 is a characteristic diagram showing the relationship between temperature and time when the wafer is normally on the step of the wafer holder and in an abnormal state that protrudes from the step.
[Explanation of symbols]
11 ... Vacuum container,
12 ... lid,
13 ... wafer,
14 ... Wafer holder,
15 ... Rotating body,
16 ... step,
17 ... Heater,
18 ... Rotation introduction mechanism,
19 ... Thermometer sensor head,
20 ... Optical fiber,
21 ... Radiation thermometer body,
22 ... Calculator,
23 ... Control panel,
24… Analog signal line.

Claims (2)

A vacuum container in which a wafer is disposed, a wafer stage disposed in the vacuum container and having a step for dropping the wafer, a rotating mechanism for rotating the wafer stage, a heater for heating the wafer, A thermometer for measuring the temperature of the wafer, and a calculator electrically connected to the thermometer and discriminating a wafer deviation based on a temperature distribution of the wafer obtained by the thermometer. Wafer displacement detection device. The thermometer is composed of a radiation thermometer body, a thermometer sensor head, and an optical fiber connecting the radiation thermometer body and the thermometer sensor head, and the thermometer sensor head is directly above the peripheral edge of the wafer. The wafer shift detection device according to claim 1, wherein the wafer shift detection device is provided so as to be positioned.

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