JPH09218104A - Temperature measuring device for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely measure the temperature of a substrate under treatment without being infulenced by a noise such as a high frequency for generating a plasma by providing a dimension measuring means for measuring the dimension of a specified part of a substrate, and a calculating means for calculating the temperature of the substrate on the basis of the measurement result. SOLUTION: A laser beam is emitted from a light emitting part 2a into a treatment chamber A through a window B1 to irradiate a substrate 10, the image of the shadow of the substrate is gained through a window B2, and delivered to a calculating part 3. In the calculating part 3, the relation between the temperature and the outer dimension of the substrate 10 is preliminarily prepared from the relation of the thermal expansion by the heat of the substrate 10 to be measured. The calculating part 3 utiizes this to measure the diameter of the substrate from a signal showing the substrate 10 from a light receiving part 2b, and determines the temperature corresponding to the diameter. Thus, even during the treatment of the substrate 10 within the treatment chamber A, the temperature of the substrate 10 can be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate temperature measuring device for measuring the temperature of a substrate when the substrate is processed inside a processing chamber.

[0002]

2. Description of the Related Art Conventionally, it has been difficult to measure the temperature of a substrate such as a silicon wafer during a process in which a process is performed by generating plasma such as etching, CVD, and sputtering in a semiconductor process. That is, in the temperature measurement using the thermocouple, the temperature of the substrate cannot be accurately measured due to the influence of the noise due to the high frequency for generating the plasma.

In recent years, as patterns have become finer, the substrate temperature in process conditions has become an important parameter, and it has become indispensable to monitor the temperature of the substrate during processing.

Therefore, in the infrared radiation thermometer, the temperature is measured by irradiating the silicon wafer with infrared rays and changing the wavelength of the reflection. Further, there are various types of fluorescent optical fiber thermometers shown in FIGS. 5 (a) and 5 (b).

That is, in the thermometer shown in FIG. 5 (a), the fluorescent substance 21 is covered with heat-resistant cement 22, and this is covered with a spring 23.
It is attached to the tip of the ceramics terminal 24 that is urged by and is projected onto the surface of the base S.

In the thermometer shown in FIG. 5B, the fluorescent substance 21 is applied to the inside of the aluminum cap 25, and the fluorescent substance 21 in the aluminum cap 25 is passed from the optical fiber 26.
The temperature is measured by irradiating a certain amount of light on the above and obtaining the amount of light attenuation from the reflected light.

As another thermometer, there is an optical interference type one shown in the schematic view of FIG. In this, the substrate 10 placed on the base S is irradiated with infrared laser light from the laser emitting section 31, and the laser receiving section 32 receives the light reflected by the front and back surfaces of the substrate 10. Then, the temperature is calculated by the calculation unit 33 from the relationship between the interference fringes generated by the reflected light and the time.

[0008]

However, in the infrared radiation thermometer described above, since the wavelength of infrared rays passes through the silicon wafer, the temperature of the base on which the silicon wafer is placed must be measured. become. In order to measure the temperature of the silicon wafer with this thermometer, it is necessary to form a metal film such as aluminum on the surface thereof.

Further, the fluorescent optical fiber thermometer is not affected by noise due to plasma, but since the sensor portion is projected from the surface of the base on which the substrate is placed, a slight amount of spring is applied when the substrate is placed. Then, the substrate floats, and the holding of the substrate by the electrostatic chuck becomes insufficient, resulting in inconvenience in processing. Moreover, since it is a contact type, there is a problem that a measurement error occurs depending on a contact method and a contact angle.

Further, in the optical interferometry, although the temperature of the substrate can be measured in a non-contact manner, it is impossible to distinguish whether the temperature has risen from a fall or has fallen from a rise, and the temperature difference from the change point cannot be distinguished. It will be added as it is, resulting in a measurement error. Further, since the reflection of the laser light from the front surface and the back surface of the substrate is received, there arises a disadvantage that the substrate having the front surface and the back surface polished and used must be used.

[0011]

SUMMARY OF THE INVENTION The present invention is a substrate temperature measuring device which has been made to solve such problems. That is, the present invention is a substrate temperature measuring device for measuring the temperature of a substrate placed inside a processing chamber, and a dimension measuring means for measuring a dimension of a predetermined portion of the substrate and a measurement result by the dimension measuring means. And a calculation means for calculating the temperature of the substrate based on the calculation result.

In the present invention, the dimension measuring means measures the outer dimensions such as the diameter and thickness of the substrate arranged inside the processing chamber, and the calculating means calculates the temperature of the substrate based on the measurement result. There is. That is, the calculation means uses the relationship between the temperature of the substrate and the external dimensions of the predetermined portion based on the relationship between the expansion and contraction of the substrate due to heat. Based on the external dimensions of the predetermined portion measured by the dimension measuring means, the substrate The temperature of is calculated. As a result, the temperature of the substrate in the processing chamber can be measured without performing the temperature measurement process on the substrate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a substrate temperature measuring apparatus of the present invention will be described below with reference to the drawings. FIG.
[FIG. 3] is a schematic cross-sectional view (side view) illustrating the first embodiment. That is, the temperature measuring device 1 according to the first embodiment
Is for measuring the temperature of the substrate 10 such as a silicon wafer placed on the base S (lower electrode) in the processing chamber A,
A light emitting unit 2a that emits a predetermined laser beam from the outside of the chamber B into the processing chamber A through a window B1 provided in the chamber B of the processing chamber A, and a laser beam that passes through the window B2 of the chamber B are received. The light receiving unit 2b and the calculation unit 3 that calculates the temperature of the substrate 10 based on the signal obtained from the light receiving unit 2b are included.

For example, in the case of an etching device for etching the substrate 10, a gas supplier 4 for feeding a predetermined gas into the chamber B, an exhaust device 5 for exhausting the processing chamber A, and a base. A high frequency power source 7 for applying a high frequency is provided to the lower electrode, which is S.

In order to measure the temperature of the substrate 10 placed on the base S, laser light is irradiated from the light emitting portion 2a into the processing chamber A through the window B1 to hit the substrate 10 and then the window B2. An image of the shadow of the substrate 10 is acquired via and is passed to the calculation unit 3.

The calculation section 3 is prepared in advance as a function or table data of the relationship between the temperature and the outer dimension of the substrate 10 based on the relationship of expansion and contraction due to heat of the substrate 10 to be measured. Using this, the calculation unit 3 measures, for example, the diameter of the substrate 10 from the signal indicating the substrate 10 sent from the light receiving unit 2b, and obtains the temperature corresponding to the diameter.

This makes it possible to measure the temperature of the substrate 10 while the substrate 10 is being processed in the processing chamber A. Particularly, in recent years, a substrate 1 such as a wafer
Since the diameter of 0 is increasing, the amount of expansion and contraction due to heat is large. Therefore, the temperature can be calculated accurately from the outer dimensions of the substrate 10.

FIG. 2 is a schematic sectional view (upper surface) for explaining the first embodiment. In the first embodiment, the outer shape measuring unit for measuring the diameter of the substrate 10 is mainly configured by the light emitting unit 2a and the light receiving unit 2b. However, since the substrate 10 is scanned with parallel light rays, the rotating polygon mirror 2c is used. , A reflection mirror 2d, a collimator lens 2e, and a light receiving lens 2f.

With such a configuration, the laser light emitted from the light emitting portion 2a is reflected by the rotating polygon mirror 2c while changing the angle, and further reflected by the reflecting mirror 2d toward the collimator lens 2e.

The light passing through the collimator lens 2e becomes a parallel light beam, and scans the substrate 10 in the chamber B through the window B1. The scanning width of the parallel rays is set sufficiently larger than the diameter of the substrate 10. The parallel light beam scanning the substrate 10 passes through the window B2 and is condensed by the light receiving lens 2f. By scanning the parallel rays, the place where the substrate 10 is present becomes dark, the place where the substrate 10 is not present becomes bright, and the light receiving portion 2b outputs an electric signal according to the lightness.

The calculation unit 3 calculates the diameter of the substrate 10 based on the time of the electric signal corresponding to the darkness sent from the light receiving unit 2b. The calculation unit 3 has the relationship between the temperature and the diameter of the substrate as shown in FIG. 3 as a function or table data, and uses this to obtain the temperature from the diameter of the substrate 10.

In the first embodiment, the example in which the diameter of the substrate 10 is measured to calculate the temperature has been described, but the thickness of the substrate 10 may be measured to calculate the temperature. Also,
As the laser light emitted from the light emitting unit 2a, a wavelength that is not affected by measurement even if plasma is generated in the processing chamber A may be selected.

Next, a second embodiment of the present invention will be described. FIG. 4 is a schematic sectional view (upper surface) for explaining the second embodiment.
It is. The second embodiment is characterized in that the diameter of the substrate 10 is mechanically measured using the claws 4a and 4b.

That is, in a state where the substrate 10 is placed on the base S, the substrate 10 is contacted so as to be sandwiched by the claws 4a and 4b from both sides. The displacement amount of the diameter due to the thermal expansion and thermal contraction of the substrate 10 is converted into the rotation angle of the claws 4a and 4b. For example, the rotation angle is read by a micrometer, converted into an electric signal by an encoder, and passed to the calculation unit 3 shown in FIG. 1, and the diameter of the substrate 10 is calculated from the displacement amount.

After that, as in the first embodiment, the temperature of the substrate 10 is obtained from the calculated diameter using a function or table data showing the relationship between the temperature and the diameter of the substrate 10.

In the second embodiment, since the diameter of the substrate 10 is mechanically measured, it is not affected by plasma at all. In addition, the claws 4a and 4b are provided on both sides of the substrate 10.
Since the measurement is performed by sandwiching the substrate, the adhesion between the substrate 10 and the base S is not impaired, and thus the substrate can be reliably held by the electrostatic chuck.

In the above embodiment, an example in which the temperature measuring device 1 is applied to an etching device has been described.
The present invention can be applied to other manufacturing apparatuses such as an apparatus and a sputtering apparatus. Further, although the silicon wafer has been described as an example of the substrate 10, the same applies to a substrate made of another material such as a compound semiconductor wafer or a glass substrate. Also, substrate 1
The means for measuring the outer shape of 0 is not limited to the above embodiment, and may be measured by other means.

[0028]

As described above, the substrate temperature measuring apparatus of the present invention has the following effects. That is,
In the present invention, since the outer dimensions of the substrate are measured and the temperature is calculated based on the outer dimensions, it is possible to reliably measure the temperature of the substrate being processed without being affected by noise such as high frequency for plasma generation. Is possible. Further, it becomes possible to perform stable temperature measurement regardless of the state of the front surface or the back surface of the substrate.

[Brief description of drawings]

FIG. 1 is a schematic sectional view (side view) illustrating a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view (upper surface) illustrating the first embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a substrate temperature and a diameter.

FIG. 4 is a schematic sectional view (upper surface) illustrating a second embodiment of the present invention.

FIG. 5 is a schematic sectional view illustrating a conventional example.

FIG. 6 is a schematic diagram illustrating a conventional example.

[Explanation of symbols]

1 Temperature Measuring Device 2a Light Emitting Part 2b Light Receiving Part 2c Polygon Mirror 2d Reflecting Mirror 2e
Collimator lens 2f Light receiving lens 3 Calculation unit 4a, 4b Claw
10 substrate A processing chamber B chamber B1 and B2 window

Claims (3)

[Claims] 1. An apparatus for measuring the temperature of a substrate disposed inside a processing chamber, comprising: a dimension measuring means for measuring a dimension of a predetermined portion of the substrate; and a measuring result obtained by the dimension measuring means. A substrate temperature measuring device, comprising: a calculating means for determining the temperature of the substrate. 2. The temperature measuring device for a substrate according to claim 1, wherein the calculating means obtains the temperature of the substrate based on the dimension from a relationship of expansion and contraction of the substrate due to heat. 3. The dimension measuring means measures the dimension of a predetermined portion of the substrate disposed inside the processing chamber from outside the processing chamber through a window provided in an outer container of the processing chamber. The temperature measuring device for a substrate according to claim 1, wherein: