JP2000352506A - Film thickness measuring device and method thereof, thin film manufacturing equipment and method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain film thickness at a predetermined thickness together with measuring the film thickness with high accuracy in equipment that travels a base film with a magnet film in a vacuum layer to form a DLC film on this base film by a film-formation source. SOLUTION: Refractive index and extinction coefficient of before-film- formation (a base film 7 with a magnetic film) are determined by fitting optical features ψ, δ measured by a spectrum ellipsometry measuring part 9a before film-formation. Optical features ψ, δ of a film (the base film 7 with a magnetic film plus a DLC film) of after-film-formation (after-the film-formation 8-passing) at a position same as a position of before-film-formation by a spectrum ellipsometry measuring part 9b. Then, film thickness of the DLC film film- formed by inputting the refractive index and extinction coefficient of before-film- formation as already-known values to the optical features ψ, δmeasured by the spectral ellipsometry measuring part 9b and fitting them. The film thickness is maintained at a predetermined thickness by specified film thickness control (feedback) in response to this determined film thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sputtering or CVD, in which a base film with a magnetic film is run in a vacuum to produce a thin film of diamond-like carbon with a constant thickness.
More particularly, the present invention relates to an apparatus and a method for measuring a film thickness and an apparatus and a method for manufacturing a thin film.

[0002]

2. Description of the Related Art Conventionally, diamond-like carbon (hereinafter referred to as DLC) is applied to a base film with a magnetic film in a vacuum.
In an apparatus for forming a thin film, a method for accurately measuring in-line a DLC thin film formed to a thickness of 10 nm or less has not been established. The reasons were the following three. (1) The measuring machine is limited because the measuring film is extremely thin, 10 nm or less. (2) Since the DLC thin film is almost transparent and has a thickness of 10 nm or less, it is greatly affected by the magnetic film below the DLC film. (3) The optical characteristics of the magnetic film below the DLC depend on the crystal structure of the base film with the magnetic film, and the measurement results are different at the same substrate even when the measurement is performed.

As a measuring instrument for solving the reason (1),
There is a spectral ellipso. This spectroscopic ellipsometer is a measuring instrument with a proven track record in semiconductors and the like, and is nondestructive and has a high measurement speed. The method of measuring the film thickness in this spectral ellipsometer is performed by a kind of simulation called fitting.

[0004] The fitting is a currently known formula for calculating ψ, δ with respect to the measured optical characteristics ψ, δ (change in the angle of output light when the light is projected, change in phase). By substituting the data for each term, and simulating the data group of each term that shows the same characteristic as the measured value, the film thickness is obtained directly and indirectly from this data group as the optimal solution. . At this time, the smaller the number of items to be simulated, the higher the accuracy of the film thickness and the shorter the time required for the simulation.

[0005]

However, in measuring the film thickness by the above-mentioned spectral ellipsometer, it is necessary to obtain the optical constant of the underlying surface (magnetic film) in order to measure the DLC film thickness more accurately. In addition, other optical measuring devices are affected by the magnetic film as described in the reason (2), and there is a problem of the magnetic film itself as described in the reason (3). Did not.

Since the film thickness measurement cannot be performed in-line as described above, the following calibration has been performed when actually forming a film on a product. (A) The film forming conditions are the same as those for forming the product, the running speed of the base film with the magnetic film alone is reduced to about several tenths, and a test product is formed which is thicker than the product. (B) The test product of (A) is cut, and the cut surface is measured by an electron microscope (TEM). (C) Divide the measurement result of the electron microscope by the traveling speed to calculate the tape traveling speed for forming a film to a target film thickness. (D) At the time of manufacture, the DLC film thickness during film formation was controlled by managing the tape running speed obtained in (C).

[0007] Therefore, the DLC film thickness of the product varies slightly more than ± 10% due to a slight fluctuation of the film forming rate.

The present invention has been made in view of the above points, and an object of the present invention is to provide a film thickness measuring apparatus, a method thereof, and a thin film capable of performing highly accurate film thickness measurement and keeping the film thickness more constant. An object of the present invention is to provide a manufacturing apparatus and a method thereof.

[0009]

(1) A film thickness measuring apparatus according to the present invention for solving the above-mentioned problems comprises: a first spectral ellipsometer for measuring optical characteristics of a substrate before film formation; A second step of measuring the optical characteristics of the substrate after the film formation and at a location measured by the first spectroscopic ellipsometer
A spectral ellipsometer measuring unit, and a first optical constant is calculated by a predetermined method based on the optical characteristics measured by the first spectral ellipsometer measuring unit, and the first optical constant is set as a known value. An arithmetic unit for inputting optical characteristics measured by the second spectral ellipsometer measurement unit and calculating the thickness of the thin film by a predetermined method is provided (claim 1).

[0010] Further, the predetermined method is fitting in spectral ellipsometry (claim 2).

According to another aspect of the present invention, there is provided a film thickness measuring method comprising: a first measuring step of measuring an optical characteristic of a substrate before film formation; and the substrate after film formation. A second measuring step of measuring an optical characteristic of the portion measured in the first measuring step, and a first optical constant by a predetermined method based on the optical characteristic measured in the first measuring step. Calculating the first optical constant as a known value and inputting the optical characteristic to the optical characteristic measured in the second measuring step, and calculating the film thickness of the thin film by a predetermined method. (Chart 3).

Further, the predetermined method is a fitting in spectral ellipsometry (claim 4).

According to another aspect of the present invention, there is provided a thin film manufacturing apparatus comprising: a first spectral ellipsometer for measuring optical characteristics of a substrate before film formation; and the substrate after film formation. A second spectroscopic ellipsometer measuring the optical characteristics of the portion measured by the first spectroscopic ellipsometer, and a predetermined method based on the optical characteristics measured by the first spectroscopic ellipsometer A first optical constant is calculated, and the first optical constant is input as a known value to an optical characteristic measured by the second spectroscopic ellipsometer, and the thickness of the thin film is determined by a predetermined method. And a control unit for controlling the film forming conditions in accordance with the film thickness calculated by the calculating unit (claim 5).

Further, the control section performs a first control for controlling a traveling speed of the substrate traveling in opposition to the film forming source (claim 6).

[0015] Further, the control section performs a second control for controlling the power of the film forming source (claim 7).

Further, the control section performs the first control and the second control for controlling the power of the film forming source (claim 8).

Further, the predetermined method is a fitting in spectral ellipsometry (claims 9 to 12).

According to another aspect of the present invention, there is provided a method of manufacturing a thin film, comprising: a first measuring step of measuring an optical characteristic of a substrate before film formation; and the substrate after film formation. Calculating a first optical constant by a predetermined method based on the second measuring step of measuring the optical characteristics of the portion measured in the first measuring step and the optical characteristics measured in the first measuring step; Inputting the first optical constant as a known value to the optical characteristics measured in the second measurement step, and calculating the thickness of the thin film by a predetermined method;
A control step of controlling a film forming condition in accordance with the film thickness calculated in the calculating step (claim 13).

Further, the control step is characterized by performing a first control for controlling a traveling speed of a substrate traveling opposite to a film forming source (claim 14).

Further, the control step is to perform a second control for controlling the power of the film forming source (claim 15).

Further, the control step includes the first control,
The second control for controlling the power of the film forming source is performed (claim 16).

Further, the predetermined method is a fitting in spectral ellipsometry (claims 17 to 20). (2) In the film thickness measuring apparatus and method according to claims 1 to 4 of the present invention, a first optical constant (for example, a refractive index and an extinction coefficient) calculated based on optical characteristics measured before film formation. ) Is input as a known value to the optical characteristics measured after the film formation, and fitting is performed in, for example, spectral ellipsometry, so that the number of calculation formula items to be simulated at the time of fitting is reduced.

Therefore, the film thickness can be obtained with high accuracy without being affected by the film quality of the substrate serving as the base, for example, the base film with the magnetic film. (3) In the thin film manufacturing apparatus and method according to claims 5 to 20 of the present invention, the first optical constant (for example, refractive index, extinction coefficient, etc.) calculated based on optical characteristics measured before film formation. ) Is input as a known value to the optical characteristics measured after the film formation, and for example, fitting in spectral ellipso is performed, so that the number of calculation formula items to be simulated at the time of fitting is reduced.

For this reason, the film thickness is required to be highly accurate without being affected by the film quality of the substrate serving as the base, for example, the base film with the magnetic film.

The first control (step) is performed in accordance with the film thickness measured with high precision as described above. For example, when the measured film thickness is smaller than a desired film thickness, the base film with magnetic film (substrate) ), The running speed is reduced, and when it is thick, the running speed is increased. As a result, the film thickness of the film can be kept constant.

In addition, the second film is formed according to the film thickness measured with high accuracy.
Is performed, for example, when the measured film thickness is smaller than a desired film thickness, the power of the film forming source is increased, and when the measured film thickness is thicker, the power of the film forming source is reduced. As a result, the film thickness of the film can be kept constant.

As described above, the film can be formed while measuring the film thickness with high accuracy.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. First, in order to measure the DLC film thickness with high accuracy, it is necessary to simulate the above-described formulas for calculating the optical characteristics ψ and δ (change in angle of output light and change in phase when light is projected). It needs to be as small as possible.
FIG. 1 shows a configuration of an apparatus which realizes this, performs the measurement of the thickness of the DLC film with high accuracy in-line, and can keep the film thickness more constant.

In FIG. 1, 1 is a vacuum chamber, and 2 is an exhaust device. An unwind reel 3, a take-up reel 4, guide rolls 5a and 5b, and a main roller 6 are provided in the vacuum chamber 1. The base film 7 with the magnetic film between the unwinding reel 3 and the take-up reel 4 is wound around guide rolls 5a, 5b and a main roller 6, and travels as the main roller 6 rotates to be taken up on the take-up reel 4 side. Can be Reference numeral 8 denotes a film forming source for forming a DLC film on the base film 7 with a magnetic film.

Between the film forming source 8 and the unwinding reel 3, a spectroscopic ellipsometer 9a for measuring optical characteristics (ψ, δ at a wavelength of 250 to 850 nm) of the base film 7 with a magnetic film before film formation. Is provided. The spectroscopic ellipsometer 9a includes an ellipso light emitter 10a and an ellipso light receiver 11a.
a.

Between the film forming source 8 and the take-up reel 4, the optical characteristics (wavelength 250 to 850) of the base film with a magnetic film after film formation (the base film with a magnetic film 7 + DLC film).
A spectroscopic ellipsometer 9b for measuring ψ, δ in nm is provided. The spectroscopic ellipsometer 9b includes an ellipsometer light emitter 10b and an ellipsometer light receiver 11b.

The measurement outputs of the spectroscopic ellipsometers 9a and 9b are guided to an arithmetic unit (not shown) such as a computer.

As described above, in the present embodiment, the spectroscopic ellipsometers 9a and 9b are arranged before and after the DLC film formation to be in-line, and the film formation can be performed while measuring the film thickness.

Next, the operation of the apparatus configured as described above will be described with reference to the film thickness control flowchart of FIG. First, in step S1, the spectroscopic ellipsometer 9a
Before film formation, the optical characteristics (ψ, δ at a wavelength of 250 to 850 nm) of the base film 7 with a magnetic film are measured. Then, in step S2, the measured values of ψ and δ are fitted and optical constants such as a refractive index and an extinction coefficient before DLC film formation (a base film with a magnetic film) are obtained by calculation.

Next, in step S3, after the film formation (the film formation source 8) at the same position of the base film with the magnetic film measured by the spectral ellipsometer 9b by the spectral ellipsometer 9b.
(After passing) film (base film with magnetic film 7 + DL)
C film) optical characteristics (ψ at wavelength 250 to 850 nm)
δ) is measured.

Next, in step S4, the optical characteristics ψ and δ measured by the spectroscopic ellipsometer 9b are added to the refractive index before film formation (the magnetic film below the DLC film) calculated in step S2. Enter information such as the extinction coefficient as a known value (a value that does not need to be changed by simulation),
By performing fitting, the film thickness of the formed DLC is obtained by calculation.

As described above, since the calculation results before the film formation are used for the calculations after the film formation, the items of the calculation formula to be simulated at the time of the fitting are reduced, and the DLC of the high accuracy which is not affected by the film quality of the underlying magnetic film. Film thickness can be measured.

Further, the spectroscopic ellipsometers 9a and 9b are
C Since the in-line arrangement is performed before and after the film formation, the positions of the tape (the base film 7 with the magnetic film) measured by each of the spectroscopic ellipsometers 9a and 9b are set to almost the same position, and the optical measurement before and after the film formation is performed almost simultaneously. (The distance between the spectroscopic ellipsometers 9a and 9b is 5 m or more in the actual device, so the measurement timing is shifted by this distance.) ing).

Next, in step S5, predetermined film thickness control (feedback) is performed according to the film thickness measured with high precision as described above. That is, for example, when the measured film thickness is smaller than the target film thickness, the rotation speed of the main roller 6 is reduced to reduce the traveling speed of the base film 7 with a magnetic film, and conversely, when the measured film thickness is thicker, the rotation speed of the main roller 6 is reduced. To increase the running speed. As a result, the film thickness of the film can be kept constant.

For example, when the measured film thickness is smaller than the target film thickness, the power of the film forming source 8 is increased, and when it is thicker, the power of the film forming source 8 is weakened. As a result, the film thickness of the film can be kept constant.

Further, the number of rotations of the main roller 6 and the power of the film forming source 8 may be controlled simultaneously.

As described above, since the film formation is performed in-line while measuring the film thickness with high accuracy, the film thickness accuracy of the DLC film to be formed can be kept more constant.

The substrate in the present invention is not limited to the base film 7 with a magnetic film, and the thin film is not limited to a DLC film. That is, in the above embodiment, the present invention is applied to the measurement and film formation of the DLC film on the magnetic surface. However, the present invention is not limited to this and can be applied to many other films.

For example, the present invention can be applied to the measurement and film formation of a lubricant film further provided on the DLC film. Also, in a device in which a plurality of chambers are arranged in-line, such as a film forming device such as a mini-disc, a spectral ellipsometer is provided before and after each chamber, and processing is performed in the same manner as described above, so that highly accurate film thickness measurement can be performed. .

[0045]

(1) As described above, claims 1 to 5 of the present invention.
According to the film thickness measuring apparatus and the method according to No. 4, the first optical constant (for example, refractive index, extinction coefficient, etc.) calculated based on the optical characteristics measured before film formation is defined as a known value.
By inputting the optical characteristics measured after film formation and performing fitting in, for example, spectral ellipsometry, the number of calculation formula items to be simulated at the time of fitting is reduced, and thereby, a base serving as a base, for example, a base film with a magnetic film The film thickness can be determined with high accuracy without being affected by the film quality of the film.

Further, the spectral ellipsometric measuring units can be arranged in-line by being arranged before and after the film forming source, whereby the positions to be measured by each spectral ellipsometric measuring unit are made substantially the same, and almost simultaneously before and after the film forming. Optical measurement can be performed, and more accurate film thickness measurement can be performed. (2) According to the thin film manufacturing apparatus and the method therefor according to claims 5 to 20 of the present invention, a base serving as a base as described above,
For example, the film thickness can be determined with high accuracy without being affected by the film quality of the base film with a magnetic film, and the film thickness to be formed can be automatically controlled (feedback) based on the measured film thickness with high accuracy. it can. As a result, the film thickness of the film can be kept constant. Therefore, film formation can be performed while measuring the film thickness with high accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of operation according to an embodiment of the present invention.

[Description of Signs] 1 ... Vacuum chamber, 2 ... Exhaust device, 3 ... Unwinding reel, 4 ... Winding reel, 5a, 5b ... Guide roll, 6 ... Main roller, 7 ... Base film with magnetic film, 8 ... Membrane source, 9
a, 9b: a spectroscopic ellipsometer measuring section; 10a, 10b: an ellipso light emitting section; 11a, 11b: an ellipso light receiving section.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 21/21 G01N 21/21 Z G11B 5/84 G11B 5/84 C F-term (Reference) 2F065 AA30 BB13 BB15 CC02 CC31 DD00 FF44 FF49 GG13 HH08 HH12 JJ01 JJ05 JJ08 LL67 NN20 PP16 2G059 AA02 BB10 EE02 EE05 JJ01 MM01 4K029 AA11 AA25 BA34 BD11 CA05 EA00 EA01 EA09 4K030 BA28 CA07 KA07 CA12 AA12CA12 JA12 BC

Claims (20)

[Claims] An apparatus for measuring a film thickness when a thin film is formed on a substrate, comprising: a first spectroscopic ellipsometer for measuring optical characteristics of the substrate before film formation; A second spectroscopic ellipsometer that measures the optical characteristics of the location measured by the first spectroscopic ellipsometer, and a predetermined spectrometer based on the optical characteristics measured by the first spectroscopic ellipsometer Calculating the first optical constant by the method,
A calculating unit that inputs the first optical constant as a known value to an optical characteristic measured by the second spectral ellipsometer measuring unit and calculates the thickness of the thin film by a predetermined method. A film thickness measuring device characterized by the above-mentioned. 2. The film thickness measuring apparatus according to claim 1, wherein the predetermined method is fitting in spectral ellipsometry. 3. A method for measuring a film thickness when a thin film is formed on a substrate, comprising: a first measuring step of measuring optical characteristics of the substrate before film formation; and the substrate after film formation; And a second measuring step of measuring an optical characteristic of the portion measured in the first measuring step; and a first optical constant by a predetermined method based on the optical characteristic measured in the first measuring step. And calculating the first optical constant as a known value and inputting the optical characteristic measured in the second measurement step to the film thickness of the thin film by a predetermined method. A film thickness measuring method, characterized in that: 4. The method according to claim 3, wherein the predetermined method is fitting in spectral ellipsometry. 5. An apparatus for forming a thin film on a substrate, comprising: a first spectroscopic ellipsometer measuring unit for measuring an optical characteristic of the substrate before film formation; and the substrate after film formation; A second spectroscopic ellipsometer for measuring an optical characteristic of a portion measured by the spectroscopic ellipsometer, and a first optical ellipse by a predetermined method based on the optical characteristic measured by the first spectroscopic ellipsometer Calculate the constant,
An arithmetic unit that inputs the first optical constant as a known value to an optical characteristic measured by the second spectral ellipsometer, and calculates the thickness of the thin film by a predetermined method; And a controller for controlling a film forming condition in accordance with the film thickness calculated in the step (a). 6. The thin-film manufacturing apparatus according to claim 5, wherein the control unit performs a first control for controlling a traveling speed of the substrate traveling in opposition to the film forming source. 7. The thin film manufacturing apparatus according to claim 5, wherein the control unit performs a second control for controlling a power of a film forming source. 8. The thin film manufacturing apparatus according to claim 6, wherein the control unit also performs a second control for controlling a power of a film forming source. 9. The apparatus according to claim 5, wherein the predetermined method is fitting in spectral ellipsometry. 10. The thin film manufacturing apparatus according to claim 6, wherein the predetermined method is fitting in spectral ellipsometry. 11. The apparatus according to claim 7, wherein the predetermined method is fitting in spectral ellipsometry. 12. The thin film manufacturing apparatus according to claim 8, wherein said predetermined method is fitting in spectral ellipsometry. 13. A method for forming a thin film on a substrate, comprising: a first measuring step of measuring an optical characteristic of the substrate before film formation; and the first measuring step, wherein the substrate is formed after film formation. Calculating a first optical constant by a predetermined method based on the optical characteristic measured in the first measuring step, and a second measuring step of measuring the optical characteristic of the portion measured in the first step. Calculating the optical constant of the thin film as a known value into the optical characteristics measured in the second measurement step, and calculating the film thickness of the thin film by a predetermined method; and the film calculated in the calculation step A method for controlling the film formation conditions according to the thickness. 14. The thin film manufacturing method according to claim 13, wherein the control step performs a first control for controlling a traveling speed of a substrate traveling opposite to a film forming source. 15. The thin film manufacturing method according to claim 13, wherein the control step performs a second control for controlling a power of a film forming source. 16. The thin film manufacturing method according to claim 14, wherein said control step also performs a second control for controlling a power of a film forming source. 17. The method according to claim 13, wherein the predetermined method is fitting in spectral ellipsometry. 18. The method according to claim 14, wherein the predetermined method is fitting in spectral ellipsometry. 19. The method according to claim 15, wherein the predetermined method is fitting in spectral ellipsometry. 20. The method according to claim 16, wherein the predetermined method is fitting in spectral ellipsometry.