JPH0722482A - Film-thickness measuring device and thin-film forming device using film-thickness measuring device - Google Patents

Abstract

PURPOSE:To provide a film-thickness measuring technique capable of precisely measuring film thickness without affected by the physical properties of a thin- film to be measured. CONSTITUTION:A pair of electrodes 5c are arranged on the bottom of a recessed section 5b notched at the central section of an insulating substrate 5a at a regular interval and the electrodes 5c are connected to an electric-resistance measuring instrument 5e through a lead 5d in a film-thickness measuring device 5. The recessed section 5b of the insulating substrate 5a is disposed near a wafer in the treating chamber of a thin-film forming device in an attitude, in which the recessed section 5b is directed toward an evaporation source, and a thin-film 2b is formed simultaneously between the wafer and the electrode 5c of the recessed section 5b by substance vapor 2a generated from the evaporation source. An electric resistance value between the electrodes 5c measured by the electric-resistance measuring instrument 5e is reduced gradually in response to the increase of the film thickness (t) of the thin-film 2b, and the film thickness (t) of the thin-film 2b is determined from the change of the electric resistance value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film thickness measuring technique and a thin film forming technique using the same, and more particularly to a technique effective when applied to a thin film forming step in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art For example, in a semiconductor device manufacturing process, a thin film made of a desired substance is formed on the surface of a semiconductor substrate (wafer) by a method such as vapor deposition or chemical vapor deposition. By the way, in such a thin film forming step, it is required to precisely control the film thickness of the thin film to a target value, for example, in the unit of μm.

For this reason, conventionally, for example, a quartz oscillator whose physical properties such as natural frequency are known is placed together in a processing atmosphere in which a wafer on which a thin film is formed is placed, and a quartz crystal is formed as the thin film is formed on the wafer. It has been known that the thickness of a thin film deposited and formed on a wafer is indirectly measured by measuring the change in the physical properties of the crystal oscillator due to the thin film attached to the oscillator and converting it to the film thickness. .

[0004]

However, in the above-mentioned conventional techniques, the change in the physical properties of the crystal unit cannot be converted into the thickness of the thin film unless the physical properties such as the specific gravity of the thin film to be formed are known. was there. In addition, there is a problem that the measurement accuracy is not so high and precise measurement is difficult.

An object of the present invention is to provide a thin film measuring technique capable of accurately measuring the film thickness without being affected by the physical properties of the thin film to be measured.

Another object of the present invention is to provide a thin film forming technique capable of precisely controlling the forming speed and the film thickness of a thin film formed on an object.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0008]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

That is, the film thickness measuring apparatus of the present invention comprises an insulating substrate, electrodes arranged on the insulating substrate at a predetermined interval, and electric resistance measuring means for measuring an electric resistance value between the electrodes. The film thickness of a thin film of a desired conductive substance deposited between the electrodes of the insulating substrate is measured based on the electric resistance value between the electrodes.

Further, the film thickness measuring apparatus of the present invention comprises an insulating substrate, electrodes arranged on the insulating substrate at a predetermined interval, and an electric capacitance measuring means for measuring an electric capacitance value between the electrodes. The film thickness of a thin film of a desired conductive substance deposited between the electrodes of the insulating substrate is measured based on the capacitance value between the electrodes.

Further, the film thickness measuring device of the present invention comprises a light source for generating a desired measuring light, a light amount detecting means for measuring the light amount of the measuring light incident from the light source, and a light amount detecting means for the light source. Consisting of a transparent substrate provided on the optical path of the measuring light to reach, the film thickness of the thin film of the desired substance deposited on the transparent substrate, of the light quantity of the measuring light transmitted through the thin film and the transparent substrate. Further, the thin film forming apparatus of the present invention comprises the film thickness measuring apparatus according to claim 1, 2 or 3, and measures the film thickness of the thin film formed on a desired object. It is something to measure.

[0012]

According to the film thickness measuring device of the present invention described in claim 1, the film thickness of the conductive thin film can be accurately measured as follows. That is, as illustrated in FIG. 5, the electric resistance R of the conductive substance is R = L / S (1) (where R: electric resistance, L: length, S: disconnection). If the distance (length) L between the electrodes is accurately measured in advance, the resistance value of the thin film is proportional only to the cross-sectional area S, and the cross-sectional area S is proportional only to the film thickness t. Therefore, the film thickness t of the thin film deposited between the electrodes can be accurately obtained from the resistance value between the electrodes measured by the electric resistance measuring means.
Further, as compared with the case of measuring mechanical characteristics such as a natural frequency of a crystal oscillator or the like, the influence of disturbance or the like due to the measurement environment is small, and high measurement accuracy can be realized.

Further, according to the film thickness measuring device of the present invention as defined in claim 2, since the electric capacitance between the electrodes is proportional to the film thickness of the thin film, the film thickness of the thin film can be accurately measured. Further, in this case, the thin film does not necessarily have to be conductive, and there is an advantage that the film thickness of the thin film of a wider range of substances can be measured.

Further, according to the film thickness measuring device of the present invention as defined in claim 3, the transmittance of the measuring light incident from the light source to the light amount detecting means is proportional to the film thickness of the thin film deposited on the transparent substrate. The film thickness of the thin film deposited on the transparent substrate can be accurately measured from the measurement result of the measurement light incident on the light amount detection means. Also in this case, the thin film does not necessarily have to be conductive, and there is an advantage that the film thickness of a thin film of a wider range of substances can be measured.

Further, according to the thin film forming apparatus of the present invention, since the film thickness measuring apparatus according to claim 1, 2 or 3 is used,
The thickness of the thin film formed on the object can be precisely controlled.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic sectional view showing an example of a film thickness measuring apparatus which is an embodiment of the present invention.
FIG. 3 is a conceptual diagram showing an example of a thin film forming apparatus using the same.

First, an outline of the thin film forming apparatus 1 of this embodiment will be described with reference to FIG. In the following description, a vapor deposition apparatus will be described as an example of the thin film forming apparatus 1, but it goes without saying that the present invention is not limited to this.

An evaporation source 6 is provided inside the sealed processing chamber 3.
Is provided therein, and a conductive evaporation substance 2 which is a target thin film is stored therein. The evaporation source 6 includes a heater 1
0 is provided, and it is possible to heat to a temperature at which the evaporation material 2 evaporates. A vacuum exhaust system 11 is connected to the processing chamber 3 so that the inside of the processing chamber 3 can be exhausted to a desired high vacuum.

A wafer 4 supported by a holding mechanism (not shown) is arranged in the upper portion of the processing chamber 3 in such a manner that a target thin film forming surface faces the lower evaporation source 6. 6
The conductive thin film 2b made of the vaporized substance 2 is formed by coming into contact with the substance vapor 2a generated from.

The heater 10 for heating the evaporation source 6 is connected to the film thickness controller 7 via a heater ON / OFF switch 9 and a heater control system 8. The film thickness controller 7 includes a heater control system 8 and a heater ON / O.
By controlling the heating state of the evaporation material 2 by the evaporation source 6 via the FF switch 9, the control operation such as the formation speed of the thin film 2b on the wafer 4 and the start / stop of the thin film formation operation is performed.

In this case, a film thickness measuring device 5 is provided inside the processing chamber 3.

In this film thickness measuring device 5, for example, as shown in FIG. 1, a pair of electrodes 5c are arranged at a predetermined interval on the bottom of a recess 5b formed in the center of an insulating substrate 5a. The electrode 5c is connected to the lead wire 5
It is connected to the electric resistance measuring device 5e via d.

In the film thickness measuring apparatus 5 having the above-described structure, the wafer 4 inside the processing chamber 3 of the thin film forming apparatus 1 is placed with the concave portion 5b of the insulating substrate 5a facing the evaporation source 6. It is located in the vicinity. The distance and posture of the film thickness measuring device 5 with respect to the evaporation source 6 are set to be equal to those of the wafer 4 with respect to the evaporation source 6, and the thin film 2b is formed in both the wafer 4 and the film thickness measuring device 5. Consideration is made so that conditions such as speed are equivalent.

The electric resistance measuring device 5e of the film thickness measuring device 5 is
It is connected to the film thickness controller 7 of the thin film forming apparatus 1. In the case of the present embodiment, the film thickness controller 7 is
Based on the electric resistance value between the electrodes 5c obtained from the electric resistance measuring device 5e, the thickness t of the thin film 2b formed at the same time as the surface of the wafer 4 is monitored, and the thickness of the thin film 2b becomes a target dimension. Therefore, the operation of controlling the evaporation source 6 is performed.

An example of the operation of the film thickness measuring device 5 and the thin film forming device 1 in this embodiment will be described below.

First, the evaporation source 6 is heated in a state where the inside of the processing chamber 3 is at a predetermined vacuum degree, and the substance vapor 2a of the evaporation substance 2 is generated inside the processing chamber 3. As a result, the thin film 2b starts to be formed on the surface of the wafer 4 which is in contact with the substance vapor 2a. At this time, at the same time, the concave portion 5b of the film thickness measuring device 5
The thin film 2b starts to be formed in a similar state between the electrodes 5c inside the electrode 5c measured by the electric resistance measuring device 5e.
As is clear from the principle illustrated in FIG. 5, the electric resistance value between them gradually decreases as the film thickness t of the thin film 2b increases.

The film thickness controller 7 monitors the change in the film thickness t of the thin film 2b based on the electric resistance value and controls the heating operation of the evaporation source 6 by the heater 10 via the heater control system 8. , The deposition rate of the thin film 2b is controlled to a target value.

The electric resistance value between the electrodes 5c measured by the electric resistance measuring device 5e and the actual film thickness t of the thin film 2b.
The value of the film thickness t can be precisely known by previously obtaining the relationship between and by an experiment or the like and calibrating the actually measured value.

Thus, the thin film 2b formed on the wafer 4
When the thickness reaches a target value, the operation of forming the thin film 2b is stopped, and the processed wafer 4 is taken out of the processing chamber 3.

As described above, according to the film thickness measuring apparatus of this embodiment, the thin film 2b is formed by the simple operation of measuring the electric resistance value of the thin film 2b formed between the pair of electrodes 5c.
The film thickness t can be precisely known without the need to measure other physical properties such as b. Further, the film thickness measuring device 5 includes
Since there is no part that mechanically operates, much higher measurement accuracy can be realized as compared with, for example, a conventional mechanical measurement method using a crystal oscillator or the like.

Therefore, according to the thin film forming apparatus 1 using the film thickness measuring apparatus 5 of this embodiment, the forming speed (film quality) and film thickness of the thin film 2b formed on the wafer 4 can be precisely adjusted to desired values. It can be controlled, and good thin film formation results can be obtained.

(Embodiment 2) FIG. 3 is a conceptual diagram showing an example of the structure of a film thickness measuring apparatus 51 which is another embodiment of the present invention.

In the case of the second embodiment, the light source 51b composed of a laser light source and the light amount detector 51c are arranged to face each other with the transparent substrate 51a on which the thin film 2b is formed adhered therebetween, and the light is emitted from the light source 51b. The change in the film thickness t of the thin film 2b is known by observing the change in the intensity of the measurement light 51d that passes through the thin film 2b and the transparent substrate 51a and is incident on the light amount detector 51c.

That is, as the film thickness t of the thin film 2b deposited on the transparent substrate 51a increases, the light quantity detector 51c increases.
Since the intensity of the measuring light 51d incident on is gradually reduced, this intensity change can be converted to the film thickness t of the thin film 2b and accurately obtained. In addition, in the case of the third embodiment, the substance forming the thin film 2b does not necessarily have to be conductive, and there is an advantage that the thin film 2b of various substances can be precisely measured.

(Embodiment 3) FIG. 4 is a conceptual diagram showing an example of the construction of a film thickness measuring apparatus 52 which is still another embodiment of the present invention.

In the case of the third embodiment, a pair of electrodes 52b are arranged at a predetermined interval on the insulating substrate 52a on which the thin film 2b is formed, and the capacitance between the electrodes 52b is measured by the capacitance. It is measured by the instrument 52c. That is, the thickness t of the thin film 2b deposited and formed on the insulating substrate 52a is precisely measured by measuring the electric capacitance between the electrodes 52b which varies according to the change of the thickness t. Also in the case of the third embodiment, the substance forming the thin film 2b does not necessarily have to be conductive, and there is an advantage that the thin film 2b of various substances can be precisely measured.

Although the invention made by the inventor has been described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. Absent.

[0039]

The effects obtained by the representative one of the inventions disclosed in the present application will be briefly described as follows.

That is, according to the film thickness measuring apparatus of the present invention, it is possible to obtain an effect that the film thickness can be accurately measured without being affected by the physical properties of the thin film to be measured.

Further, according to the thin film forming apparatus of the present invention, there is an effect that the forming speed, film quality, film thickness and the like of the thin film formed on the object can be precisely controlled.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a film thickness measuring apparatus which is an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an example of a thin film forming apparatus using the same.

FIG. 3 is a conceptual diagram showing an example of a configuration of a film thickness measuring device which is another embodiment of the present invention.

FIG. 4 is a conceptual diagram showing an example of the configuration of a film thickness measuring apparatus which is still another embodiment of the present invention.

FIG. 5 is a conceptual diagram showing an example of a measurement principle of the film thickness measuring device of the present invention.

[Explanation of symbols]

 1 Thin Film Forming Device 2 Evaporated Substance 2a Substance Vapor 2b Thin Film t Film Thickness 3 Processing Chamber 4 Wafer 5 Film Thickness Measuring Device 5a Insulating Substrate 5b Recess 5c Electrode 5d Lead Wire 5e Electric Resistance Meter 6 Evaporation Source 7 Film Thickness Controller 8 Heater Control system 9 Heater ON / OFF switch 10 Heater 11 Vacuum exhaust system 51 Film thickness measuring device 51a Transparent substrate 51b Light source 51c Light intensity detector 51d Measuring light 52 Film thickness measuring device 52a Insulating substrate 52b Electrode 52c Capacitance measuring device

Claims (4)

[Claims] 1. An insulating substrate, an electrode arranged on the insulating substrate at a predetermined interval, and an electric resistance measuring means for measuring an electric resistance value between the electrodes. A film thickness measuring device, characterized in that a film thickness of a thin film of a desired conductive substance deposited between electrodes is measured based on an electric resistance value between the electrodes. 2. An insulating substrate, electrodes arranged at predetermined intervals on the insulating substrate, and capacitance measuring means for measuring a capacitance value between the electrodes. A film thickness measuring device, characterized in that a film thickness of a desired thin film of a conductive substance deposited between electrodes is measured based on an electric capacitance value between the electrodes. 3. A light source for generating a desired measuring light, a light amount detecting means for measuring the light amount of the measuring light incident from the light source, and an optical path of the measuring light from the light source to the light amount detecting means. And a transparent substrate provided on the transparent substrate, the thin film of the desired substance deposited on the transparent substrate, the film thickness is measured based on a change in the light amount of the measurement light transmitted through the thin film and the transparent substrate. And a film thickness measuring device. 4. A thin-film forming apparatus comprising the film-thickness measuring apparatus according to claim 1, wherein the thin-film forming apparatus measures the thickness of a thin film formed on a desired object.