JP3308775B2 - CVD equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CVD apparatus,
In particular, the present invention relates to a CVD apparatus for measuring a gap length using laser light.

[0002]

2. Description of the Related Art FIG. 13 is a sectional view showing the structure of a conventional atmospheric pressure CVD apparatus. In FIG. 13, the wafer 1 is held on the wafer stage 2 by vacuum suction, and the main surface (the surface on which the CVD film is formed) of the wafer 1 is arranged vertically downward. The wafer stage 2 has a heating mechanism for heating the wafer, but the description is omitted.

[0003] The wafer stage 2 has a rotation mechanism for rotating the wafer stage 2. The rotation mechanism has a large gear 3 and a small gear 4, and a stepping motor 5 is connected to the small gear 4 as a drive source.

The gas head 6 faces the wafer stage 2.
Is arranged. The gas head 6 is a perforated plate that uniformly blows a material gas for forming a CVD film onto the wafer 1 and is attached to an opening of a mixing vessel 61 for mixing various material gases. In addition, a plurality of gas introduction pipes 7 for introducing a material gas are attached to the mixing container 61. In the mixing container 61, various material gases are mixed uniformly and the pressure inside the container is kept uniform. , A perforated plate having smaller holes than the gas head 6.

The wafer stage 2 and the mixing vessel 61 are arranged so as to be inserted into upper and lower openings of the reaction vessel 10. A sealing ring (X-ring) 11 for preventing a material gas from flowing out of the reaction vessel 10 due to the rotation of the wafer stage 2 is fitted on the outer periphery of the wafer stage 2.

The reaction vessel 10 comprises a gas head 6 and a wafer 1
And a vertical movement mechanism for changing the gap (gap length) between them. The vertical movement mechanism is a device that moves the reaction vessel 10 in the vertical direction by rotating the ball screw 8,
A support plate 8 supporting the reaction vessel 10 is provided on the reaction vessel 10.
2 is connected, and a servomotor 9 as a drive source is connected to the ball screw 8.

The mixing vessel 61 is connected to a plurality of support columns 81, and the support columns 81 penetrate the support plate 82 and are fixed to a base (not shown). Accordingly, the reaction vessel 10 moves up and down. Since the wafer stage 2 moves up and down as the reaction chamber 10 moves up and down,
The gap length between the gas head 6A above the fixed mixing container 61A and the wafer 1 adsorbed on the wafer stage 2A changes.

On the inner surface of the lower opening of the reaction vessel 10, a sealing ring (O-ring) 11 for preventing material gas from flowing out of the reaction vessel 10 due to vertical movement of the reaction vessel 10 is provided.
Is inlaid.

An exhaust pipe 13 for exhausting a material gas is connected to the center of the reaction vessel 10, and the exhaust pipe 13 is connected to an exhaust mechanism (not shown). Also,
Although gates for loading and unloading the wafer 1 are provided in a direction (not shown), a detailed description is omitted because the relationship with the present invention is thin.

The reaction vessel 10 has a structure that can be divided into upper and lower parts by a dividing part 101 below the exhaust pipe 13. In addition, a sealing ring for preventing the material gas from flowing out of the reaction vessel 10 is provided in the division part 101.

Next, the operation will be described with reference to FIG. The wafer 1 loaded into the reaction container 10 from a gate (not shown) by a transfer mechanism (not shown) is vacuum-sucked to the wafer stage 2. Then, the wafer 1 is heated to 400 ° C. to 500 ° C. by the heating mechanism inside the wafer stage 2 and starts rotating together with the wafer stage 2 by the rotating mechanism. The reason why the wafer 1 is rotated is to obtain a uniform thickness and quality of a thin film formed on the surface of the wafer 1. The gap length between the gas head 6 and the wafer step 2 is maintained at a predetermined value by a vertical movement mechanism.

Various material gases introduced into the mixing vessel 61 from the plurality of gas introduction pipes 7 are uniformly mixed in the mixing vessel 61 and are uniformly sprayed onto the entire surface of the wafer 1 via the gas head 6.

The material gas in contact with the surface of the wafer 1 is excited by the heat of the wafer 1 to form a thin film on the surface of the wafer 1. At this time, extra gas that does not contribute to the formation of the thin film is exhausted by the exhaust pipe 13.

In such a CVD apparatus, the flow of the material gas in the vicinity of the wafer 1 greatly changes depending on the length of the gap between the gas head 6 and the wafer stage 2 during the formation of the thin film. The length accuracy of the gap length is required to be 0.1 mm or less.

[0015]

The conventional atmospheric pressure CVD apparatus is configured as described above, and the accuracy of the length of the gap length is 0.1.
mm or less was required, but since there was no measurement mechanism for accurately measuring the gap length, the gap length and parallelism between the gas head 6 and the wafer stage 2 were measured using a gap gauge (block gauge). ) Etc. were measured manually. For this reason, it is difficult to measure with high accuracy, and there are problems such as individual differences among the measurers.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to measure the gap length and parallelism between a gas head and a wafer stage in a short time and to automatically adjust the gap length. Provide a simple CVD apparatus.

[0017]

According to a first aspect of the present invention, there is provided a CVD apparatus, comprising: a substrate mount for mounting a substrate on which a CVD film is to be formed;
A gas head for spraying a gas for forming a VD film over the entire main surface of the substrate;
In a CVD apparatus for forming a VD film, a laser length measuring device is provided on a side surface of the substrate mounting base and measures a gap length between the substrate mounting base and the gas head with a laser beam. A laser light emitting unit is disposed so as to face an edge of the gas head, and the gap length is continuously measured along the edge of the gas head as the substrate mount is rotated.

According to a second aspect of the present invention, in the CVD apparatus, the gap length may be determined such that the irradiation position of the laser beam from the laser emission unit is shifted from a predetermined position in a radial direction by an allowable value or more. The irradiation position shift reflection structure which reflects as a change of the measurement value of the irradiation position is provided.

4. The CVD apparatus according to claim 3, wherein the irradiation position deviation reflecting structure is formed along an edge of the gas head, and is formed in an annular step that recedes from a direction toward the substrate mount. It is.

5. The CVD apparatus according to claim 4, wherein the irradiation position deviation reflecting structure is formed along an edge of the gas head and projects in a direction toward the substrate mount. It is.

According to a fifth aspect of the present invention, in the CVD apparatus, the irradiation position deviation reflecting structure is a plurality of radial concave portions formed at predetermined intervals along an edge of the gas head. .

According to a sixth aspect of the present invention, in the CVD apparatus, the irradiation position deviation reflecting structure includes a plurality of radial projections formed at predetermined intervals along an edge of the gas head. is there.

According to a seventh aspect of the present invention, in the CVD apparatus, the substrate may be larger than an outer shape of the substrate mount, and the laser measuring device may be configured such that the substrate is mounted on the substrate mount. It is arranged at a position retracted from a position parallel to the main surface of the substrate mounting base so that the distance to the back surface of the substrate can be measured.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1, <A-1. Configuration of Normal Pressure CVD Apparatus 100> As a first embodiment of a CVD apparatus according to the present invention, FIG. In FIG. 1, a wafer 1 is held by vacuum suction on a wafer stage 2A serving as a substrate mounting table, and a main surface (a surface on which a CVD film is formed) of the wafer 1 is arranged vertically downward. The wafer stage 2A has a heating mechanism for heating the wafer, but the description is omitted. Further, the wafer stage 2A includes a rotation mechanism for rotating the wafer stage 2A. The rotation mechanism has a large gear 3 and a small gear 4, and a stepping motor 5 is connected to the small gear 4 as a drive source.

Here, the planar shape of the wafer stage 2A will be described. In general, the shape of the wafer 1 is not a perfect circle but a shape having a notch for positioning called an orientation flat (orientation flat), and the wafer stage 2A is also a planar shape matching the shape of the wafer 1. It has become. This is wafer stage 2
This is to prevent a region that is not covered by the wafer 1 from being formed on A and forming a thin film in that region.

Accordingly, the cross section of the wafer stage 2A is not symmetrical depending on the cutting direction. FIG.
Shows a cross-sectional shape in that case. A laser length measuring device 21 is mounted on the side of the wafer stage 2A corresponding to the orientation flat of the wafer 1.

A gas head 6A is arranged to face the wafer stage 2A. The gas head 6A is a plate having a hole for uniformly spraying a material gas for forming a CVD film onto the wafer 1, and a wafer stage 2 along the outer peripheral edge.
It has an annular step 22 that recedes from the direction A, and is attached to the opening of a mixing container 61A that mixes various material gases.

The laser length measuring device 21 is mounted on the side surface of the wafer stage 2A so that the light emitting portion faces the step 22 of the gas head 6A. The laser length measuring device 21
This device measures the distance based on the time difference until the reflected light of the laser beam emitted by itself returns, and the measurement accuracy is 0.
1 mm or less.

Here, in order to prevent the light emitting portion and the reflected light measuring portion of the laser length measuring device 21 from being contaminated by the material gas for forming the CVD film, the film formation such as nitrogen gas is not hindered at the time of film formation. Gas is blown to the laser length measuring device 21.

For this purpose, a nitrogen gas injection mechanism may be provided in the wall surface of the reaction vessel 10, or a nitrogen gas injection mechanism may be provided on the wafer stage 2A.

A plurality of gas introduction pipes 7 for introducing a material gas are attached to the mixing vessel 61A.
In 1A, a perforated plate having a hole smaller than that of the gas head 6A is provided in order to uniformly mix various material gases and keep the pressure inside the container uniform.

Wafer stage 2A and mixing vessel 61A
Are arranged to be inserted into upper and lower openings of the reaction vessel 10. A sealing ring (X ring) 1 is provided on the outer periphery of wafer stage 2A to prevent material gas from flowing out of reaction vessel 10 due to rotation of wafer stage 2A.
2 is inset.

The reaction vessel 10 has a vertical movement mechanism for changing the distance (gap length) between the gas head 6A and the wafer 1. The vertical moving mechanism is a device for moving the reaction vessel 10 in the vertical direction by rotating the ball screw 8, a support plate 82 supporting the reaction vessel 10 is connected to the reaction vessel 10, and a servo motor as a driving source is connected to the ball screw 8. 9 is connected.

The mixing container 61A is connected to a plurality of support columns 81. Since the support columns 81 are fixed to a base (not shown) through the support plates 82, the ball screws 8 are provided.
As a result, the support plate 82 moves up and down, and accordingly, the reaction vessel 10 moves up and down. Since the wafer stage 2A moves up and down as the reaction chamber 10 moves up and down, the gas head 6 above the fixed mixing vessel 61A is fixed.
The gap length between A and the wafer 1 attracted to the wafer stage 2A changes.

A sealing ring (O-ring) 11 for preventing the material gas from flowing out of the reaction vessel 10 due to the vertical movement of the reaction vessel 10 is provided on the inner surface of the lower opening of the reaction vessel 10.
Is inlaid.

An exhaust pipe 13 for exhausting a material gas is connected to the center of the reaction vessel 10, and the exhaust pipe 13 is connected to an exhaust mechanism (not shown). Also,
Although gates for loading and unloading the wafer 1 are provided in a direction (not shown), a detailed description is omitted because the relationship with the present invention is thin.

The reaction vessel 10 has a structure that can be divided into upper and lower parts by a dividing part 101 below the exhaust pipe 13. In addition, a sealing ring for preventing the material gas from flowing out of the reaction vessel 10 is provided in the division part 101.

FIG. 2 is a block diagram showing a configuration of an automatic gap length adjusting mechanism for automatically adjusting the gap length based on the data from the laser length measuring device 21.

In FIG. 2, a length measurement signal (analog signal) from a laser length measuring device 21 is connected to an A / D converter 23, converted into a digital signal by the A / D converter 23, and given to an arithmetic processing unit 24. . The arithmetic processing unit 24 determines the presence or absence of the gap length adjustment based on the digitized length measurement signal, and if the gap length adjustment is necessary, controls the pulse generator 25 to convert the pulse signal to the servo motor driver 26. Output to. The servo motor driver 26 drives the servo motor 9 in response to a pulse signal from the pulse generator 25 to move the reaction vessel 10 in the vertical direction and adjust the gap length.

A keyboard 27 is connected to the arithmetic processing unit 24 as an external input device for setting data such as a gap length, and a display for displaying the data and the length measurement result from the laser length measuring device 21. A device (display) 28 is connected. The arithmetic processing unit 2
Reference numeral 4 also controls other parts of the atmospheric pressure CVD apparatus 100, but the description is omitted because it has little relation to the present invention.

<A-2. Operation of atmospheric pressure CVD apparatus 100><A-2-1. Gap Length Measurement> First, the gap length measurement will be described with reference to FIGS. As shown in FIG. 3, before the wafer 1 is sucked, a laser beam is emitted from the laser
A distance L1 between the flat surface of the step 22 of A is measured.

Since the laser length measuring device 21 is mounted on the wafer stage 2A, the rotation mechanism rotates the wafer stage 2A, thereby the step 22 of the gas head 6A.
Along, the distance L1 is continuously measured. FIG. 4 is a graph of the continuously measured distance L1.

In FIG. 4, when the horizontal axis is a rotation angle and the vertical axis is a length measurement signal (arbitrary unit), when the wafer stage 2A and the gas head 6A are mounted in parallel, a constant measurement is indicated by a solid line. Since a long signal is obtained, it is
Let it be 1.

On the other hand, the wafer stage 2A and the gas head 6
When A is not parallel, a difference occurs in the length measurement signal as indicated by a dashed line, and a maximum value L1MAX and a minimum value L1MIN of the distance L1 are obtained.

Then, the difference between L1MAX and L1MIN,
That is, the parallelism between the wafer stage 2A and the gas head 6A is adjusted so that the fluctuation error becomes 0.1 mm or less.
In addition, as a method of adjusting the parallelism, since the gas head 6A is fixed as described above,
The inclination of A is adjusted, and the adjustment is performed by interposing a thin plate spacer or the like at the connection between the reaction vessel 10 and the support plate 82, or by equalizing the joining strength of the divided portions of the reaction vessel 10.

<A-2-2. Automatic gap length adjustment> When the distance L1 is obtained within a variation error of 0.1 mm, an operation for matching the set value of the gap length and the measured value is performed next.

Here, a method for deriving the gap length from the distance L1 will be described with reference to FIG. As shown in FIG. 5, the distance L1 is the distance L0 between the wafer stage 2A and the gas head 6A, that is, the gap length, the distance L2 from the laser length measuring device 21 to the back surface of the wafer 1 attracted to the wafer stage 2A, Distance L of head of step 22 of gas head 6A
3 and the sum. Since the distance L3 is a known value, if the distance L2 is known, the distance L0, that is, the gap length can be obtained by subtracting the distance L2 and the distance L3 from the distance L1.

Since the distance L2 does not change unless the position of the laser length measuring device 21 is changed, it can be used as a known value by previously measuring and recording the value.

Therefore, assuming that the gap length to be set is the distance L, the distance L, the distance L3 and the distance L2 are inputted from the keyboard 27, and the arithmetic processing unit 24 calculates the distance L1 and the distance L2 and the distance L3 Is subtracted to determine the distance L0, and by comparing with the distance L, it is determined whether the set value matches the measured value.

Here, the distance L1 has a fluctuation error of 0.1 due to the adjustment of the parallelism between the wafer stage 2A and the gas head 6A.
mm, but in other words, it changes within a range of 0.1 mm.
The distance L0 is obtained by subtracting the distance L2 and the distance L3 from the AV. The average value LAV is calculated based on the length measurement signal measured in the parallelism adjustment step.

If the distance L0 and the distance L do not match, the number of rotation angles of the servo motor 9 is calculated to determine how many times the difference corresponds, and the servo motor 9 is further rotated by that angle. To calculate the number of pulse signals to be supplied to the servo motor driver 26 from the pulse generator 25, the pulse generator 25 is controlled to generate a pulse signal.

Since the servo motor driver 26 rotates the servo motor 9 according to the pulse signal given from the pulse generator 25, the reaction vessel 10 is moved vertically by a predetermined distance (difference between the distance L0 and the distance L) and the measurement is performed. The value will match the set value.

<A-2-3. Alignment of Wafer Stage and Gas Head> Next, the alignment of the wafer stage 2A and the gas head 6A will be described with reference to FIGS.

As described above, the reaction vessel 10 has a structure that can be divided into upper and lower parts by the division part 101 below the exhaust pipe 13. At the time of maintenance, the reaction vessel 10 is vertically divided by the dividing section 101, and after the maintenance is completed, the vertically divided reaction vessels 10 are joined.

In order to prevent the central axes of the wafer stage 2A and the gas head 6A from shifting during bonding, the dividing section 10
No. 1 has a fitting structure having a step, and no significant axis deviation occurs. However, it was not possible to confirm with a conventional CVD apparatus whether or not the central axes coincided within an allowable value.

However, in the atmospheric pressure CVD apparatus 100, a step 22 is provided in the gas head 6A so that the laser beam is irradiated from a vertical plane of the step 22 of the gas head 6A to a position separated by a predetermined distance equal to an allowable value. Laser measuring device 2
In the case where the irradiation position of the laser beam is shifted in the radial direction by more than the allowable value by attaching 1, the deviation of the irradiation position is reflected as a change in the length measurement signal of the laser length measuring device 21. Wafer stage 2A causing position shift
And the axial deviation of the gas head 6A can be confirmed. Therefore, it can be said that the step 22 has an irradiation position shift reflecting structure that reflects the shift of the irradiation position of the laser beam.

For example, when the center axes of the wafer stage 2A and the gas head 6A coincide, as shown in FIG.
The laser length measuring device 21 is mounted so that the laser beam emitted from the laser length measuring device 21 is irradiated to the point A on the flat surface of the step 22, reflected, and returned to the laser length measuring device 21. This A
The distance from the point to the vertical plane of the step 22 is the allowable value.

Even if the center axes of the wafer stage 2A and the gas head 6A are displaced, the amount of the displacement is
If the distance is within the distance to the vertical plane, that is, within the allowable value, the laser beam is applied to the flat surface of the step 22, so that the distance L1 is measured as shown in FIG. Therefore, the central axes of the wafer stage 2A and the gas head 6A are not deviated.

On the other hand, the wafer stage 2A and the gas head 6
When the shift amount of the central axis of A exceeds the distance from the point A to the vertical plane of the step 22, that is, when the laser beam is applied to the porous surface of the gas head 6A as shown in FIG. The distance measured by the container 21 is a distance L1 ′ shorter than the distance L1 by the distance L3 of the step 22.

FIG. 7 is a graph showing the results of continuous measurement while rotating the wafer stage 2A in such a case.

In FIG. 7, assuming that the horizontal axis is the rotation angle and the vertical axis is the length measurement signal (arbitrary unit), when the wafer stage 2A and the gas head 6A are mounted in parallel and there is no axis deviation, as shown by the solid line. , A constant length measurement signal is obtained, and the distance is a distance L1.

On the other hand, the wafer stage 2A and the gas head 6
When A is not parallel and there is an axis deviation exceeding the allowable value, a difference occurs in the length measurement signal as indicated by a dashed line, and the laser light is sharply applied to the portion where the porous surface of the gas head 6A is irradiated. A large drop occurs. This drop corresponds to the distance L3, which indicates that the distance L1 has become the distance L1 ', and exists in the range of the rotation angle of B degrees.

When the laser beam is applied to the flat surface of the step 22 of the gas head 6A, the head does not drop and the length measurement signal shows a value close to the distance L1.

As described above, by performing continuous measurement while rotating the wafer stage 2A, it is possible to confirm whether or not there is an axis shift between the wafer stage 2A and the gas head 6A.

The rotation mechanism of the wafer stage 2A is
An origin sensor for detecting the origin of rotation is provided, and the position where the origin sensor is turned ON is set as the origin, that is, 0 degrees.

Since the stepping motor is used, the angle from the origin can be known from the number of pulses. Therefore, it is possible to know the occurrence angle and the end angle of the sudden drop of the length measurement signal, and to know the direction of the axis deviation from the middle between them, that is, the middle angle of the range B degrees.

When it is determined that the axis deviation between the wafer stage 2A and the gas head 6A has occurred, the axis deviation is adjusted by adjusting the fitting state of the divided portions 101 while paying attention to the direction of the axis deviation. Fix it.

<A-2-4. Confirmation of presence / absence of wafer suction> Measurement of gap length, automatic adjustment of gap length, adjustment of parallelism between wafer stage 2A and gas head 6A, axis of wafer stage 2A and gas head 6A without mounting wafer 1 When all the conditions are satisfied, the wafer 1 is loaded into the reaction vessel 10 from a gate (not shown) by a transfer mechanism (not shown), and
Is adsorbed in vacuum. Then, the wafer 1 is heated to 400 ° C. to 500 ° C. by the heating mechanism inside the wafer stage 2A, and starts rotating together with the wafer stage 2A by the rotating mechanism. The reason why the wafer 1 is rotated is to obtain a uniform thickness and quality of a thin film formed on the surface of the wafer 1.

Various material gases introduced into the mixing vessel 61A from the plurality of gas introduction pipes 7 are uniformly mixed in the mixing vessel 61A, and are uniformly sprayed onto the entire surface of the wafer 1 via the gas head 6A.

The material gas in contact with the surface of wafer 1 is excited by the heat of wafer 1 to form a thin film on the surface of wafer 1. At this time, extra gas that does not contribute to the formation of the thin film is exhausted by the exhaust pipe 13.

When a series of film forming steps are completed, the material gas is exhausted, the wafer 1 on which the film has been formed is unloaded, and a new wafer 1 is unloaded instead, and the same steps are repeated.

Here, in the conventional CVD apparatus, it was not possible to automatically confirm whether or not the wafer 1 was securely attracted to the wafer stage 2 by vacuum.

However, the atmospheric pressure CVD apparatus 10 according to the present invention
At 0, when the wafer 1 is vacuum-sucked on the wafer stage 2, a laser beam is emitted from the laser length measuring device 21 to automatically determine whether the wafer 1 is vacuum-sucked on the wafer stage 2. You can check.

That is, when the wafer 1 is vacuum-sucked on the wafer stage 2, as shown in FIG. 5, the back surface of the wafer 1 is irradiated with a laser beam, and the length measurement result indicates the distance L 2.
However, when the wafer 1 is not vacuum-adsorbed to the wafer stage 2, the laser beam is applied to the step 22 of the gas head 6A.
Is irradiated on the flat surface, and the length measurement result is the distance L1. Therefore, when the wafer 1 is vacuum-adsorbed to the wafer stage 2, a laser beam is emitted from the laser length measuring device 21 to set a routine for measuring the distance, thereby automatically detecting an abnormal attachment / detachment of the wafer 1. be able to.

The normal pressure CVD apparatus 100 described above
In the above, the configuration having the step 22 in the direction of retreating from the wafer stage 2A is shown along the outer peripheral edge of the gas head 6A, but the configuration has an annular step protruding toward the wafer stage 2A. Is also good.

<A-3. Characteristic Effects> As described above, according to the first embodiment of the CVD apparatus of the present invention, the laser measuring device is mounted on the wafer stage, and the distance between the wafer stage and the gas head while rotating the wafer stage. By measuring the gap length, the gap length can be measured accurately in a short time, the gap length can be automatically adjusted, the parallelism between the wafer stage and the gas head can be measured,
It is possible to obtain a CVD apparatus capable of automatically detecting the presence or absence of an axis deviation between the wafer stage and the gas head and automatically detecting an abnormal mounting / detaching of the wafer.

Embodiment 2, <B-1. Configuration of Normal Pressure CVD Apparatus 200> FIG. 8 shows a configuration of a normal pressure CVD apparatus 200 as a second embodiment of the CVD apparatus according to the present invention. In FIG. 8, wafer stage 2
A gas head 6B is arranged to face A. The gas head 6B has a plurality of radial concave portions 30 on the outer peripheral edge.

The laser length measuring device 21 is mounted on the side surface of the wafer stage 2A so that the light emitting portion faces the concave portion 30 of the gas head 6B.

FIG. 9 is a plan view of the gas head 6B as viewed from the direction of arrow C in FIG. As shown in FIG. 9, the concave portions 30 are provided at equal intervals along the outer peripheral edge of the gas head 6B, and the concave depth is also uniform. In FIG. 9, the porous portion is formed in a region indicated by a dashed line, but a detailed diagram is omitted.

The atmospheric pressure CVD apparatus 100 shown in FIG.
The same components as those described above are denoted by the same reference numerals, and redundant description will be omitted.

<B-2. Operation of Normal Pressure CVD Apparatus 200>
In the atmospheric pressure CVD apparatus 200 having the above-described configuration, the wafer stage 2A and the gas head 6B are arranged in parallel, and when there is no misalignment, the wafer stage 2A is continuously rotated by using the laser length measuring device 21 while rotating the wafer stage 2A. FIG. 10 is a graph of the result of the length measurement.

In FIG. 10, when the horizontal axis is the rotation angle and the vertical axis is the length measurement signal (arbitrary unit), the distance L10 and the distance L11
And a length measurement signal that periodically changes into a pulse wave shape between the two is obtained. Here, the distance L10 is a distance between the laser length measuring device 21 and the flat surface of the concave portion 30 of the gas head 6B, and corresponds to the distance L1 in the normal pressure CVD apparatus 100 of the first embodiment.

The distance L11 is the distance between the laser length measuring device 21 and the porous surface of the gas head 6B, and is shorter than the distance L10 by the drop of the concave portion 30, and is equal to the normal pressure CVD apparatus 100 of the first embodiment. Corresponds to the distance L1 ′.

Therefore, by measuring the distance between the wafer stage and the gas head while rotating the wafer stage, the gap length can be accurately measured in a short time. The rotation speed of the wafer stage 2A can be monitored by measuring the period T1 during which the distance L10 is measured and the period T2 during which the distance L11 is measured using the reference clock of the arithmetic processing unit 24. Therefore, it can be confirmed whether wafer stage 2A is rotating at the rotation speed set in arithmetic processing unit 24.
The rotation angle can also be monitored by counting the number of times the distance L10 and the distance L11 have changed.

FIG. 11 shows an example of the result of continuous measurement using the laser length measuring device 21 while rotating the wafer stage 2A when the wafer stage 2A and the gas head 6B are not arranged in parallel. FIG.

If the wafer stage 2A and the gas head 6B are not arranged in parallel, a difference occurs in the length measurement signal, and the maximum value L10MAX and the minimum value L10 of the distance L10 are generated.
MIN will be obtained. Then, the parallelism between the wafer stage 2A and the gas head 6B is adjusted so that the difference between L10MAX and L10MIN, that is, the variation error is 0.1 mm or less.

In FIG. 12, when the center axes of the wafer stage 2A and the gas head 6B deviate beyond an allowable value, the length is continuously measured using the laser length measuring device 21 while rotating the wafer stage 2A. FIG. 5 is a graph showing an example of the result of performing the above.

In FIG. 11, when there is a radial axis deviation larger than the allowable value, a portion where the laser beam is not irradiated to the concave portion 30 but continues to be irradiated to the porous surface of the gas head 6B appears, so that the distance L11 is measured. The period during which the axis shift is longer than when there is no axis shift (period T2 ′) and the periodicity is lost, so that the presence or absence of an axis shift between the wafer stage 2A and the gas head 6A can be confirmed. Therefore, it can be said that the concave portion 30 has an irradiation position shift reflecting structure that reflects the shift of the irradiation position of the laser beam.

<B-3. Characteristic Effects> As described above, according to the second embodiment of the CVD apparatus of the present invention, a plurality of recesses are regularly formed in the outer peripheral edge of the gas head, and the wafer stage is rotated. By measuring the distance between the wafer stage and the gas head, the gap length can be measured accurately in a short time, and the rotation speed of the wafer stage can be monitored by the change cycle of the length measurement signal. C to check whether the wafer stage is rotating at the set rotation speed
A VD device can be obtained. Also, automatic adjustment of gap length, measurement of parallelism between wafer stage and gas head,
Needless to say, it is possible to automatically detect the presence or absence of the axis deviation between the wafer stage and the gas head, and the abnormal attachment / detachment of the wafer.

Further, the normal pressure CVD apparatus 200 described above
In the above, the configuration in which the plurality of concave portions 30 are provided on the outer peripheral edge of the gas head 6B has been described, but a configuration in which a plurality of radial convex portions are provided instead of the concave portions 30 may be used.

In the modified examples of the embodiment and the first and second embodiments of the CVD apparatus according to the present invention described above,
Although a step or a concave portion is provided at the outer peripheral edge of the gas head and the laser beam is applied to the portion, the step or the concave portion is only required to measure the gap length between the wafer stage and the gas head. A concave portion is not necessary, and a structure in which a laser beam is directly irradiated on a porous surface of a gas head is sufficient. Note that even in such a configuration, it is possible to measure the parallelism between the wafer stage and the gas head.

In the first and second embodiments of the CVD apparatus according to the present invention described above, the specific structure of the atmospheric pressure CVD apparatus has been described. However, the wafer stage is arranged to face the gas head, and the wafer is rotated. The application of the present invention is not limited to a normal pressure CVD apparatus as long as the film is formed while performing the film formation.

[0093]

According to the CVD apparatus of the first aspect of the present invention, the laser emitting section of the laser length measuring device is disposed so as to face the edge of the gas head, and the rotation of the substrate mounting table is performed. Accompanying this, the gap length is continuously measured along the edge of the gas head, so if the substrate mount is not parallel to the gas head, the gap length changes with rotation, and the degree of parallelism is determined from the degree of the change. A detectable CVD device can be obtained.

According to the CVD apparatus of the second aspect of the present invention, since the gas head has the irradiation position shift reflecting structure, the shift of the irradiation position of the laser beam in the radial direction is detected, so that the substrate is mounted. It is possible to obtain a CVD apparatus capable of detecting a shift between the center of the table and the center axis of the gas head.

According to the third aspect of the present invention, the laser beam is applied to the main surface of the gas head in a portion where the irradiation position of the laser beam is shifted in the radial direction. The measured value of the gap length is shorter than that of the portion where the irradiation position is not displaced in the radial direction, and it is possible to detect the displacement between the substrate mounting base and the central axis of the gas head. Also, the direction of the axis deviation can be obtained by comparing the portion where the measured value of the gap length is short with the rotation angle of the substrate mounting base.

According to the CVD apparatus of the fourth aspect of the present invention, the laser beam is irradiated on the main surface of the gas head in the portion where the irradiation position of the laser beam is shifted in the radial direction. The measured value of the gap length is longer than that of the portion where the irradiation position is not shifted in the radial direction, and it is possible to detect the shift between the substrate mounting base and the central axis of the gas head. Further, the direction of the axis deviation can be obtained by comparing the portion where the measured value of the gap length is long with the rotation angle of the substrate mounting base.

According to the CVD apparatus of the fifth aspect of the present invention, the laser light is formed at regular intervals in accordance with the rotation of the substrate mount in a portion where the irradiation position of the laser light is not shifted in the radial direction. Irradiated alternately on the plurality of radial recesses and the main surface of the gas head, the length of the measured gap length changes alternately and periodically, but the laser beam irradiation position shifts in the radial direction. In the part where the laser beam is irradiated on the main surface of the gas head, a region where the measured value of the gap length is short appears for a long time, and the periodicity is lost, so that the center axis of the substrate mounting base and the gas head are shifted. Can be detected. Further, the actual rotation speed of the substrate mounting table can be detected from the period of the change in the length of the measured value of the gap length.

According to the CVD apparatus of the sixth aspect of the present invention, the laser light is formed at regular intervals in accordance with the rotation of the substrate mount in a portion where the irradiation position of the laser light is not shifted in the radial direction. The radial projections and the main surface of the gas head are alternately illuminated. In the shifted portion, the laser beam is irradiated on the main surface of the gas head, so that a region where the measured value of the gap length is long appears for a long time, and the periodicity is lost, so that the substrate mounting base and the central axis of the gas head are lost. A shift can be detected. Also, the actual rotation speed of the substrate mounting table can be detected from the period of the change in the measured value of the gap length.

According to the CVD apparatus of the seventh aspect of the present invention, the laser length measuring device is arranged so that the distance to the back surface of the substrate can be measured when the substrate is mounted on the substrate mounting table. If the laser beam is emitted and the distance to the back of the board is properly obtained, it is determined that the board is mounted.If the distance to the back of the board is not properly obtained, the board is mounted. By judging that the substrate is not installed, a CVD apparatus capable of confirming whether or not the substrate is attached can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a CVD apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a gap length automatic adjustment mechanism of the CVD apparatus according to the present invention.

FIG. 3 is a diagram illustrating automatic measurement of a gap length of the CVD apparatus according to the present invention.

FIG. 4 is a view showing a result of automatic measurement of a gap length in the first embodiment of the CVD apparatus according to the present invention.

FIG. 5 is a view for explaining automatic measurement of a gap length of the CVD apparatus according to the present invention.

FIG. 6 is a diagram illustrating measurement of axis deviation of the CVD apparatus according to the present invention.

FIG. 7 is a view showing a measurement result of an axis shift in the first embodiment of the CVD apparatus according to the present invention.

FIG. 8 is a diagram illustrating a configuration of a second embodiment of the CVD apparatus according to the present invention.

FIG. 9 is a plan view of a gas head according to a second embodiment of the CVD apparatus of the present invention.

FIG. 10 is a view showing a result of automatic measurement of a gap length in a second embodiment of the CVD apparatus according to the present invention.

FIG. 11 is a view showing a result of automatic measurement of a gap length in a second embodiment of the CVD apparatus according to the present invention.

FIG. 12 is a view showing a measurement result of an axis shift in the second embodiment of the CVD apparatus according to the present invention.

FIG. 13 is a diagram illustrating a configuration of a conventional atmospheric pressure CVD apparatus.

[Explanation of symbols]

2A wafer stage, 6A, 6B gas head, 21
Laser measuring instrument, 22 steps, 27 keyboard, 28
Display device, 30 concave portions, 61A, 61B mixed container.

Claims (7)

(57) [Claims] A substrate mount on which a substrate on which a CVD film is to be formed is mounted;
A gas head for spraying a gas for forming a film over the entire main surface of the substrate;
A CVD apparatus for forming a film, comprising: a laser length measuring device arranged on a side surface of the substrate mounting base and measuring a gap length between the substrate mounting base and the gas head with a laser beam. The laser light emitting unit is disposed so as to face the edge of the gas head, and the gap length is continuously measured along the edge of the gas head with the rotation of the substrate mounting table. CVD equipment. 2. The gas head according to claim 1, wherein the laser beam irradiation position from the laser light emitting unit deviates from a predetermined position in a radial direction by an allowable value or more as a change in the measured value of the gap length. The CVD apparatus according to claim 1, further comprising a reflection structure. 3. The CVD apparatus according to claim 2, wherein the irradiation position deviation reflection structure is an annular step formed along an edge of the gas head and retreating from a direction toward the substrate mount. 4. The C according to claim 2, wherein the irradiation position deviation reflecting structure is an annular step formed along an edge of the gas head and protruding in a direction toward the substrate mounting table.
VD device. 5. The CVD apparatus according to claim 2, wherein the irradiation position deviation reflecting structure is a plurality of radial concave portions formed at predetermined intervals along the edge of the gas head. 6. The CVD apparatus according to claim 2, wherein the irradiation position deviation reflecting structure is a plurality of radial projections formed at regular intervals along the edge of the gas head at predetermined intervals. 7. The substrate is larger than the outer shape of the substrate mount, and the laser length measuring device can measure a distance to a back surface of the substrate when the substrate is mounted on the substrate mount. 7. The CVD apparatus according to claim 1, wherein the CVD apparatus is disposed at a position retracted from a position parallel to a main surface of the substrate mount.