JP3356871B2 - Thin film production method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a thin film by a thermal CVD method, and more particularly to a method and an apparatus for producing a thin film which are characterized by a method of judging a thin film deposition start time. INDUSTRIAL APPLICABILITY The present invention is useful for a method and an apparatus for producing a metal thin film for wiring in a semiconductor integrated circuit, various display devices, various sensors, electronic components, and the like.

[0002]

2. Description of the Related Art At present, in a technique for manufacturing a semiconductor integrated circuit, a metal thin film constituting a wiring portion is manufactured by sputtering an aluminum alloy. However, in this aluminum alloy, a phenomenon in which aluminum atoms move due to energization (called electromigration) and a phenomenon in which aluminum atoms move similarly due to stress (called stress migration). ) Tends to occur.
This drawback has become a significant problem as the wiring width has been reduced with the increase in the degree of integration of semiconductor integrated circuits.
In addition, as the degree of integration of semiconductor integrated circuits increases, the operation speed of elements must be increased, and the resistance of the wiring portion must be further reduced.

In order to improve such a point, it is necessary to develop a wiring technique using a material having low resistance and good migration resistance. As such a wiring material, copper having lower resistance and better migration resistance than aluminum is promising. However, the wiring technology using copper has a different problem from that of aluminum.
The major problem is that dry etching for processing the thin film into a predetermined fine wiring shape is difficult for copper, and the fine processing characteristics of the copper thin film are poor.

A technique called a damascene method has been reported as a method for forming a fine pattern on a wiring material which is difficult to dry-etch such as copper. That is,
A groove-shaped pattern having a predetermined wiring shape is formed in advance on an insulating film (mainly a silicon oxide film), and a metal film is deposited so as to be embedded in the groove. Is a method of forming a metal film into a predetermined fine wiring shape by mechanically polishing the surface of the metal film. The point of this technique is that a predetermined metal thin film must be deposited in a groove-like pattern formed in an insulating film.

However, the conventional sputtering method cannot completely embed a metal thin film in such a fine groove pattern.

On the other hand, a thermal CVD method in which a substrate is heated and a source gas is chemically reacted by the heat to deposit a target thin film on the surface of the substrate is used in such a fine groove pattern. It is also known that a metal thin film can be completely embedded. Therefore, when the thermal CVD method and the damascene method are combined, a fine copper pattern can be formed without using a dry etching step.

[0007] As a problem of thin film production by the thermal CVD method, there is a problem of accuracy in controlling a deposited film thickness. The control of the deposited film thickness is generally performed as follows.
Assuming that the deposition rate of the film is constant during deposition,
Based on the expression “deposited film thickness = deposition rate × deposition time”, the required deposition time for the target deposited film thickness can be obtained. Here, the deposition time is a time from the start time to the end time of the film formation. Since the deposition rate can be predicted by performing preliminary experiments and the like, it is necessary to control the deposition time as accurately as possible in order to precisely control the deposited film thickness.

When the sputtering method is used, the start time and the end time of film formation can be accurately controlled by opening and closing a shutter disposed between the substrate and the target. Since the opening and closing speed of the shutter is higher than the deposition speed, it is easy to accurately control the deposition time.

On the other hand, in the thermal CVD method, the start and end of the film formation are controlled by controlling the temperature of the substrate (the time when the substrate temperature rises to a predetermined temperature is defined as the start time of the film formation, and the substrate temperature is lowered to the predetermined temperature Is achieved by controlling the time when the film formation is completed) or by controlling the supply of the raw material gas (the time when the supply is started is defined as the start time of the film formation and the time when the supply is stopped is defined as the end time of the film formation). , There are two ways. Since the latter control is faster, the start and end of the film formation are often performed by controlling the supply of the source gas.

[0010]

However, thermal CV
Either of the above two methods of controlling the deposition time in the method D has a disadvantage that it is particularly difficult to accurately specify the deposition start time. Therefore, it is difficult to accurately control the deposition time, and it is difficult to obtain a desired film thickness with good reproducibility.

The reason why it is difficult to determine the deposition start time in the thermal CVD method is as follows. In the thermal CVD method, there is often a blank time in which no deposition is observed even when the source gas is supplied, at the initial stage of deposition of the metal thin film. For example, when depositing aluminum, it takes a relatively long time before crystal nuclei necessary for crystal growth are generated. This blank time is hard to control. Once the crystal nuclei are generated, thereafter, a film having a thickness proportional to the elapsed time is formed as long as the source gas is supplied. Therefore, knowing the start time of nucleation is the key to the deposition time control.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to make it possible to accurately determine the start time of deposition of a thin film in the production of a thin film by a thermal CVD method. Is to be controlled with high accuracy, and thus the film thickness is to be accurately controlled.

[0013]

SUMMARY OF THE INVENTION The present inventor has proposed a thermal CVD method.
The method found that the state of radiation emitted from the deposition surface changed when the thin film began to deposit on the surface of the substrate, and we thought that this change in radiation would be used to determine the deposition start time. It has been reached. That is, according to the thin film manufacturing method of the present invention, in a thermal CVD method in which a substrate is heated and a raw material gas is chemically reacted by the heat to deposit a thin film on the surface of the substrate, light emitted from the deposition surface of the substrate is detected. Then, the deposition start time of the thin film is determined based on a temporal change of the detected value.

There are various methods for detecting emitted light.
What is generally called a radiation thermometer can be effectively used for detecting radiation light in the present invention. Various radiometers can also be used. A radiation thermometer is a device that measures the apparent temperature of an object by observing the heat radiation of the object, and is calibrated to give the true temperature of the black body when observing the brightness of the black body radiation Is common. Therefore, to determine the true temperature from the apparent temperature of the object (measured temperature),
Effective values of the emissivity of the object and the transmittance of the radiation in the observation path are required. Examples of the radiation thermometer include an optical pyrometer and a photoelectric thermometer. The optical pyrometer measures the luminance temperature by observing the luminance in one wavelength range of the visible region of the thermal radiation of the object. The photoelectric thermometer is for observing the luminance of heat radiation of an object in a considerably wide wavelength range from the visible to the near-infrared using a photoelectric tube or a photomultiplier tube. Radiometers measure the energy and illuminance of radiation,
Various detection elements are used. Of this radiometer,
Precise ones are also used as radiation thermometers.

In the present invention, it is not necessary to accurately measure the temperature itself and the radiant energy itself of the deposition surface of the substrate, and it is sufficient to detect only a temporal change in the state of the radiated light. Therefore, basically, any type of radiation thermometer or radiometer may be used. Also, since it is not necessary to determine the true temperature from the apparent temperature, there is no need to know the emissivity of the deposition surface of the substrate or the transmittance of radiation in the observation path.

In order to determine the temporal change in the detected value of the emitted light,
The following is preferred. That is, the detected values of the emitted light are sampled at predetermined time intervals, a moving average of the detected values of the emitted light is obtained using a plurality of latest sampling data, and the time derivative of the moving average exceeds a predetermined threshold value. The time when the deposition starts is defined as the deposition start time. In general, the detected value of the emitted light has a relatively large ratio of noise to signal, and particularly when the substrate temperature is relatively low, the S / N ratio cannot be so large. Therefore, the influence of the noise can be reduced by calculating the time differential value after cutting the noise using the moving average as described above.

The deposition start time may be determined by using a window trigger method instead of the above-described differential method. FIG. 7A is a graph illustrating the principle of the window trigger method. In a graph in which the vertical axis represents the detected value of the emitted light and the horizontal axis represents time, a window having a height of 2H and a width of W is set. Then, the midpoint in the height direction of the left side of the window is defined as the origin of the window. Synchrotron radiation detection value data line 62
To create a window at the upper point 58, a window 50 having the point 58 as the origin may be set. That is,
At the point 58, a window 50 having a height H above and below and a width W toward the right is formed. Thereafter, the data line 62 passes through one of the upper side 52, the right side 54, and the lower side 56 of the window 50. Then, when the data line 62 passes through the window 62, a next window 59 is created at the point 60. In this way, windows are sequentially formed. Hereinafter, a window when the data line 62 passes through the upper side 52 is referred to as an ascending window, a window when passing through the right side 54 is referred to as a stationary window, and a window when passing through the lower side 56 is referred to as a descending window. The illustrated window 50 is a descending window.

The data line 6 is formed by the window trigger method.
In order to determine the meaningful change of 2, the following method is used. In other words, if the rising window occurs twice consecutively in the case where the steady window has continued up to that time, that time is determined as the rising start time of the data line. Similarly, if the descending window continues two times in succession, that point is determined as the descending start time of the data line. This allows
Changes in the data line due to noise can be ignored.
In the present invention, when it is possible to determine either the time at which the data line 62 of the emission light detection value starts rising or the time at which the data line 62 starts falling, the time is set as the deposition start time of the thin film. The above-described determination condition of “two consecutive times” may be changed to an arbitrary number of consecutive times of two or more times, such as “three consecutive times”.

The window trigger method is suitable for detecting a change in data including a relatively large amount of noise.
In addition, there is an advantage that the change time can be determined without changing the raw data without performing a smoothing process such as taking a moving average of the data. The principle of the window trigger method itself is disclosed in, for example, US Pat. No. 5,190,614.

In the present invention, radiation emitted from the deposition surface of the substrate is detected, but the shape and material of the substrate are not particularly limited. Therefore, the substrate is not limited to a thin plate-like substrate such as a silicon wafer, and may have any shape.
The material of the substrate does not particularly matter in relation to the film to be deposited, and may be any material.

The present invention is suitable for forming a metal thin film by a thermal CVD method. In this case, an organic metal compound can be used as a raw material gas. For example, a thin film of aluminum can be deposited using an organometallic compound of aluminum as a source gas. Triisobutylaluminum as the organometallic compound of aluminum: Abbreviation TIBA: Formula and C ₁₂ H ₂₇ Al, dimethyl aluminum hydride: Abbreviation DMAH: Chemical formula C ₂ H ₇ Al, trimethyl aluminum: Chemical formula C ₃ H ₉ Al, triethylaluminum: Chemical formula C ₆ H ₁₅ Al can be used.

Further, a metal thin film can be prepared using an organometallic complex as a raw material gas. For example, a copper thin film can be deposited using a copper organometallic complex as a source gas. As an organometallic complex of copper, hexafluoroacetylacetonatotrimethylvinylsilane copper (I): Cu (hfac)
(Tmvs): Chemical formula C ₁₀ H ₁₃ CuF ₆ O ₂ Si or hexafluoroacetylacetonato copper (I) 2-butyne: Chemical formula C ₈ H ₅ CuF ₆ O ₂ , hexafluoroacetylacetonato copper (I) triethylphosphine : Chemical formula C ₁₁ H ₁₆ C
uF ₆ O ₂ P, bistrimethylsilyl hexafluoroacetylacetonato copper (I): Chemical formula C ₁₃ H ₁₉ CuF ₆ O ₂ S
i ₂ , copper bis (bishexafluoroacetylacetone):
Formula _{C 10 H 2 CuF 12 O 4} , bis acetylacetonate copper (II): can be used chemical formula C ₁₀ H ₁₄ CuO _4.

An aluminum thin film can be deposited using an organometallic complex of aluminum as a source gas. As the organometallic complex of aluminum, trimethylamine alane: abbreviation TMAA: chemical formula C ₃ H ₁₂ AlN or dimethylethylamine alane: chemical formula C ₄ H ₁₄ AlN can be used.

When the above-described raw material gas is used, hydrogen gas may be introduced as a carrier gas together with the raw material gas. This hydrogen gas can be expected to not only function as a carrier but also to reduce the thin film. For example, when an organometallic complex of copper is used as a source gas, the source gas contains oxygen as described above, and this oxygen may oxidize a deposited copper thin film. However, the use of hydrogen gas is expected to prevent such oxidation.

The thin-film manufacturing apparatus of the present invention is an apparatus for performing the above-described thin-film manufacturing method, and includes: a deposition chamber capable of maintaining airtightness; an exhaust device for evacuating the deposition chamber to a vacuum; In a thin-film manufacturing apparatus including a substrate holder that holds a substrate in a room, a heating device that heats the substrate, and a gas introduction mechanism that introduces a source gas into a deposition chamber, radiation light that detects radiation light from the deposition surface of the substrate. The apparatus includes a detection device and a deposition start determination device that determines a deposition start time of a thin film based on a signal from the radiation light detection device. In this case, a window through which the radiation light to be detected can pass is provided in the deposition chamber, and the radiation light detection device can be arranged on the atmosphere side of the deposition chamber, and the radiation light transmitted through the window is detected by the radiation light detection device. It can be detected.

[0026]

When the thin film begins to be deposited on the deposition surface of the substrate, the state of light emitted from the deposition surface of the substrate changes. By detecting this change, the deposition start time of the thin film can be determined. For example, radiation light is detected by a radiation thermometer, a temporal change in the detected value is obtained, and when the time derivative of the detected value exceeds a predetermined threshold value, it can be determined that deposition has started. The deposition end time may be a time when the supply of the source gas is stopped. As a result, the deposition time from the deposition start time to the deposition end time can be accurately controlled, and the film thickness can be precisely controlled in the thermal CVD method.

[0027]

FIG. 1 is a front sectional view of an example of an apparatus for carrying out a method for producing a thin film according to the present invention. The deposition chamber 10 capable of maintaining airtightness is connected to the arrow 1 via a valve 12.
Air is exhausted by the exhaust device 16 in the direction 4. A substrate holder 18 for holding a substrate 20 is disposed inside the deposition chamber 10. In this embodiment, as the substrate 20, a silicon wafer that is generally used as a substrate of a semiconductor integrated circuit is used. A substrate 20 is provided inside the substrate holder 18.
A heater 22 for heating the heater to a desired temperature is embedded. A thermocouple 24 is provided inside the substrate holder 18. The output of the thermocouple is connected to a thermostat, in which P is connected to the thyristor.
By performing the ID control, the power supplied to the heater 22 is adjusted. That is, the temperature of the substrate 20 is controlled indirectly by controlling the temperature of the substrate holder 18. If a substrate cooling mechanism such as a water cooling mechanism is provided in the substrate holder, rapid cooling of the substrate is possible. As a result, the substrate can be rapidly cooled to near room temperature after the thin film is deposited, and the substrate 20 can be taken out by opening the deposition chamber 10 to the atmosphere relatively quickly. If there is no substrate cooling mechanism,
Either wait for a long time until the substrate cools to near room temperature, or take it out in a short time while keeping the substrate at a high temperature. In the latter case, the deposited thin film on the substrate may be oxidized in the air.

The source gas is introduced into the deposition chamber 10 by the gas introduction mechanism 26. The source gas is introduced into the deposition chamber 10 from the direction of the arrow 28 via the valve 30 and the gas distribution plate 32. A heater 36 is wound around the gas distribution plate 32 and the gas supply pipe 34, and these are heated to an appropriate temperature to prevent the source gas from condensing on these wall surfaces. The lower surface of the substrate 20 faces the gas distribution plate 32,
The lower surface of the substrate 20 (the surface opposite to the surface in contact with the substrate holder) is the substrate deposition surface.

The radiation detector 40 is located outside the deposition chamber 10.
Is arranged. In this embodiment, the synchrotron radiation detection device 40
A commercially available radiation thermometer is used. The output terminal of the emitted light detection device 40 is connected to a deposition start determination device 42. Radiation 44 emitted from the deposition surface of substrate 20
Passes through the optical window 38 and is detected by the emitted light detection device 40. When the temperature of the deposition surface of the substrate 20 is 500 ° C. or less, the intensity of the emitted light in the visible region is very small.
The radiation detection device 40 in this embodiment detects radiation in the near infrared region.

An optical window 38 is provided on a side wall of the deposition chamber 10, and an optical crystal plate of barium fluoride whose surface is optically polished is used as the optical window 38. The material of the optical window 38 must be a material that can transmit light of a wavelength or a wavelength band to be detected by the radiation detection device 40.
In that regard, barium fluoride has good radiation transmission characteristics in the near-infrared region described above. When the substrate temperature is 50
In a relatively high temperature thin film production process of 0 ° C. or more,
It is possible to detect radiation in the visible region. In this case, quartz glass or Pyrex (registered trademark) glass can be used as the optical window 38. Deposition chamber 10
The space between the stainless steel wall and the optical window 38 is sealed by an O-ring made of Viton rubber (not shown).

The deposition start judging device 42 processes an output from the synchrotron radiation detecting device 40 (hereinafter referred to as synchrotron radiation detection value) to determine a thin film deposition start time. In this embodiment, the deposition start judging device 42 samples the emission light detection value every 2 milliseconds. Then, in order to cut noise included in the detected synchrotron radiation value, a 16-point moving average of the sampling data was obtained, and this was used as synchrotron radiation detection value data at that time. That is, the averaging process is performed by calculating the average value of the 16 detected synchrotron radiation values including the sampling time. A first derivative with respect to time is calculated for the averaged data, and the time when the differentiated value reaches a predetermined threshold value is defined as the deposition start time.

Next, an embodiment in which a thin film is actually produced by a thermal CVD method using the apparatus shown in FIG. 1 will be described. First, the substrate 20 is set on the substrate holder 18 in the deposition chamber 10. On the surface of the substrate 20, a thin film of titanium nitride is previously deposited as a base. Next, the deposition chamber 10 was evacuated to a pressure of 10 ⁻⁵ Torr or less using the exhaust device 16, and the substrate 20 was heated to 200 ° C. at the same time,
The gas introduction mechanism 26 was heated to 80 ° C. using the gas introduction heater 36. Open the valve 30 for gas introduction,
Hexafluoroacetylacetonatotrimethylvinylsilane copper (I) which is an organometallic complex containing copper (hereinafter referred to as Cu
(Hfac) (tmvs). ) At 0.75 g / m
in at a flow rate of 600 m
It was introduced into the deposition chamber 10 at a flow rate of 1 / min. This C
Since u (hfac) (tmvs) is a liquid at normal temperature and normal pressure, this liquid was put into a vaporizer and vaporized through a carrier hydrogen gas, and then introduced into the deposition chamber 10.
At that time, the vaporizer was heated to 70 ° C.

FIG. 2A is a graph showing the temporal change of the emission light detection value when a thin film is manufactured under the above-described conditions. The vertical axis is the emission light detection value, and the horizontal axis is time. Both are shown in arbitrary units. The time when the source gas introduction valve is opened is indicated by t0. When a radiation thermometer is used as the radiation light detection device, the radiation light detection value on the vertical axis is expressed as the apparent temperature of the deposition surface. When this synchrotron radiation detection value changes, the temperature change due to the heat of reaction may actually occur, but in many cases, the temperature does not actually change, but mainly the radiation on the deposition surface. The change in rate only appears to change the apparent temperature. The change in the emissivity of the deposition surface is caused by the start of the deposition.

In FIG. 2A, the deposition start time t1
Is determined as follows. First, in order to remove noise from the emission light detection value, 16 points of moving average processing are performed. Next, a first derivative with respect to time is obtained for the moving average. The point in time when this differential value exceeds a predetermined threshold value is defined as t1. The time when the sediment starts to be generated is at this time t
Good agreement with 1.

The time difference between the time t0 when the source gas introduction valve 30 is opened and the deposition start time t1 depends on various factors such as the operation speed of the valve 30, the rise of the vaporizer, and the rise of the carrier gas flow control. Affected by For this reason, it is very difficult to accurately predict the time difference between t0 and t1. Therefore, it is difficult to accurately control the deposition time by the conventional method in which the deposition start time is determined based only on the time t0. On the other hand, in the present invention, the actual measurement time t1 is set as the deposition start time. Therefore, if the supply of the raw material gas is stopped when a desired deposition time has elapsed from the time t1, the thin film is required for the necessary deposition time. Can be deposited, and the deposition time can be precisely controlled. As a result, the reproducibility of the film thickness was improved.

After forming the film for a predetermined time, the valve 30 is closed,
Stop the vaporizer and stop introducing the carrier gas. In this state, exhaust is performed until the pressure in the deposition chamber 10 becomes sufficiently low, and then the substrate 20 is cooled until the temperature of the substrate 20 becomes 50 ° C. or lower. Thereafter, the valve 12 is closed, nitrogen gas is introduced into the deposition chamber 10, and the interior of the deposition chamber 10 is set to atmospheric pressure.
The substrate 20 is taken out. In this manner, a copper thin film having a predetermined thickness can be deposited on the deposition surface of the substrate 20.

FIG. 2B is a graph in the case where the substrate temperature was changed to 170 ° C. and the other conditions were the same as in FIG. In this case, different from (A), the emission light detection value increases with the start of copper deposition. The difference between (A) and (B) is due to the difference in surface morphology. That is, in (B), the detected value of the radiated light is increased once because the surface roughness is large at the initial stage of the deposition, whereas in (A), the emissivity due to the deposited material is more than the effect of the surface roughness. The effect of the drop is greater than the effect. Also in the case of (B), the time point at which the time derivative of the emission light detection value exceeds a predetermined threshold value can be set as the deposition start time t1. In the graph of (B), e is the time region from when the detected value of the emitted light starts to increase until it reaches the maximum value, f is the time region from the time of the maximum value to the steady value, and after the steady value. Will be referred to as g.

FIG. 3 is an enlarged cross-sectional view schematically showing a change in the deposition state in the above-described time regions e, f, and g, and is cut along a plane perpendicular to the substrate surface. This drawing is based on what was observed with a scanning electron microscope (SEM). (E), (f), and (g) in FIG. 3 correspond to the time domain of e, f, and g in (B) in FIG. (E) of FIG.
Shows a state in which the film starts to be deposited on the deposition surface of the substrate, and the crystal nuclei 46 are in a state of being separated from each other. (F)
Is in a state where crystal nuclei are growing and being combined with adjacent nuclei. (G) is a state in which the crystal nucleus further grows and completely covers the base of the substrate. Thus, the state of crystal deposition can be monitored in real time by detecting emitted light.

FIG. 2C is a graph of the emission light detection value when the source gas is changed. That is, trimethylamine alane (hereinafter, abbreviated as TMAA), which is an organometallic complex containing aluminum, is used as a raw material gas.
Hydrogen was flowed at a flow rate of 600 ml / min as a carrier gas. Since this TMAA is solid at room temperature, it was sublimed and introduced into the deposition chamber 10. The substrate temperature was 110 ° C., and the pressure was 2 Torr. Under these conditions, a thin film of aluminum was deposited on the deposition surface of the substrate. FIG. 2C is very similar to FIG. 2B, except that the time difference between t0 and t1 is larger than that in FIG. That is, when aluminum is deposited, it takes a relatively long time until crystal nuclei are generated. As described above, when the time difference between t0 and t1 is large, the method for determining the deposition start time according to the present invention is very useful.

In order to deposit an aluminum thin film, not only the above-mentioned organometallic complex but also other organometallic compounds of aluminum such as triisobutylaluminum and dimethylaluminum hydride may be used. In addition, the method for determining the deposition start time as in the present invention is effective.

Incidentally, in the apparatus shown in FIG. 1, an alloy thin film can be produced by using a plurality of source gases in combination. That is, when an organometallic complex of copper is used as the first source gas and an organometallic complex of aluminum is used as the second source gas, an alloy film of copper and aluminum can be manufactured. First, the deposition of copper starts, and the copper crystal becomes a growth nucleus, and aluminum starts to deposit at the same time.
In this case as well, the deposition start time can be accurately determined based on the change in the emission light detection value. Further, as the second source gas, other organometallic compounds containing aluminum can be used instead of the organometallic complex of aluminum.

FIG. 4 is a graph called an Arrhenius plot when aluminum is deposited using dimethylaluminum hydride. In this graph, the horizontal axis represents the reciprocal of the deposition temperature (absolute temperature), and the vertical axis represents the logarithm of the deposition rate. This graph shows a comparison between the case where the deposition start time is determined based on the change in the synchrotron radiation detection value (this embodiment) and the case where the source gas introduction valve is opened as the deposition start time (conventional example). Is shown. Usually, it is known that the Arrhenius plot is on a straight line in a reaction-controlled state, but the experimental results of the conventional example show that the plot has poor linearity. The reason is that, since the time t0 earlier than the actual deposition start time t1 is set as the deposition start time, the deposition time as a basis for calculating the deposition rate is longer than the actual deposition time. That is, in the conventional example, a value smaller than the actual deposition rate is plotted. Moreover, at time t0
Since the time difference between the time t1 and the time t1 varies for each measurement condition, the variation in the calculated deposition rate error is not uniform. On the other hand, in the present embodiment, the linearity of the plot is very good. The reason is that the deposition start time can be accurately determined based on the change in the synchrotron radiation detection value, so that the deposition rate is accurately calculated.

In each of the above embodiments, the predetermined threshold value by the differential method is calculated by using the temperature conversion value of the radiation thermometer.
A value of about “1 ° C./10 seconds” was appropriate. The difference between time t0 and time t1 varies greatly depending on the experimental conditions.
It is about 0.5 seconds to 5 minutes.

FIG. 5 is a front sectional view of another embodiment of the apparatus for carrying out the present invention. 1 are given the same reference numerals as in the apparatus shown in FIG. 1 and the description thereof is omitted. In this apparatus, an optical window 38a and a radiation detection device 40a are arranged in a direction perpendicular to the deposition surface of the substrate 20a. Also in this case, the deposition start time t1 can be determined in the same manner as shown in FIG. The configuration as shown in FIG. 5 has an advantage that the emission light detection value can be increased compared to the case of FIG.

FIG. 6A is a graph of the detected radiated light when an aluminum thin film is deposited as in FIG. 2C by changing the material of the base of the substrate. That is, in FIG. 6A, an aluminum thin film produced by a sputtering method is used as a base of the substrate, and the material of the base and the material of the thin film are both aluminum. In this case, since the same material as that of the base is deposited, in the area g in the steady state, the detected radiated light value is almost the same as the detected radiated light value before the deposition start time t1. However, also in this case, since the emission light detection value changed when the deposition started, the deposition start time t1 could be accurately determined. 6A, the source gas is TMAA, the deposition pressure is 2 Torr, and the substrate temperature is 100 ° C.

FIG. 6B shows an example in which the detected value of the emitted light in the region g in the steady state is larger than the detected value of the emitted light before the deposition start time t1. Also in this case, the deposition start time t1 could be accurately determined. The deposition conditions in FIG. 6B are as follows: the base is an aluminum thin film formed by a sputtering method, the source gas is Cu (hfac) (tmvs), the deposition pressure is 10 Torr, and the substrate temperature is 170 ° C.

Next, a method of determining the deposition start time using the window trigger method instead of the above-described differential method will be described. In FIG. 7B, the windows are sequentially set for the data of the emission light detection values, and if the rising windows 70 and 72 continue two times from the state where the steady window continues, the second rising window 72 is found. The time point t1 is set as the deposition start time of the thin film. 2 descending windows
Even in the case of consecutive times, the deposition start time is similarly set. In FIG. 7B, the data of the emission light detection value is shown by a smooth curve. However, the data is actually noisy as shown in the graph of FIG. 2, and a window is directly set for the raw data. ing. In the embodiment, the value of half the height H of the window is about 1 ° C. in terms of the temperature converted by the radiation thermometer, and the width W of the window is about 0.1 second.

[0048]

According to the present invention, since the deposition start time is determined based on the change in the state of radiation emitted from the deposition surface, the deposition start time can be accurately determined. This allows
Accurate control of the deposition time becomes possible, and precise control of the film thickness in the thermal CVD method becomes possible.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an example of an apparatus for performing a thin film manufacturing method of the present invention.

FIG. 2 is a graph showing a temporal change of a radiation light detection value.

FIG. 3 is an enlarged cross-sectional view schematically showing a change in a deposition state.

FIG. 4 is a graph of an Arrhenius plot during aluminum deposition.

FIG. 5 is a front sectional view of another embodiment of the device for carrying out the present invention.

FIG. 6 is another graph showing a temporal change of a radiation light detection value.

FIG. 7 is a graph illustrating a window trigger method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Deposition chamber 16 Exhaust device 18 Substrate holder 20 Substrate 22 Heater 26 Gas introduction mechanism 38 Optical window 40 Synchrotron radiation detector 42 Deposition start judgment device 44 Synchrotron radiation

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akiko Kobayashi 5-8-1, Yotsuya, Fuchu-shi, Tokyo Nidec Anelva Co., Ltd. (56) References JP-A-50-7785 (JP, A) JP-A-2 JP-A-10-06036 (JP, A) JP-A-62-296512 (JP, A) JP-A-6-73069 (JP, A) JP-A-1-263275 (JP, A) JP-A-50-11452 (JP, A) U.S. Pat. No. 5,190,614 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21 / 205,21 / 365 C23C 16/00-16/56

Claims (12)

(57) [Claims] In a thermal CVD method in which a substrate is heated and a source gas is chemically reacted by the heat to deposit a thin film on the surface of the substrate, radiation emitted from the deposition surface of the substrate is detected. A thin film manufacturing method characterized in that a thin film deposition start time is determined based on a temporal change in a detected value. 2. The method according to claim 1, wherein the radiation is detected by a radiation thermometer. 3. A sampled value of the emitted light is sampled at a predetermined time interval, a moving average of the detected values of the emitted light is obtained using a plurality of latest sampling data, and a time derivative of the moving average is a predetermined value. 2. The method according to claim 1, wherein a time when the threshold value is exceeded is set as a deposition start time. 4. The method according to claim 1, wherein said deposition start time is determined by using a window trigger method. 5. The method according to claim 1, wherein the source gas is an organometallic compound, and the deposited thin film is a metal. 6. The method according to claim 5, wherein the source gas is an organometallic compound of aluminum and the deposited thin film is aluminum. 7. The method according to claim 1, wherein the source gas is an organometallic complex, and the deposited thin film is a metal. 8. The method according to claim 7, wherein the source gas is an organometallic complex of copper, and the deposited thin film is copper. 9. The method according to claim 7, wherein the source gas is an organometallic complex of aluminum, and the deposited thin film is aluminum. 10. A deposition chamber capable of maintaining airtightness, an exhaust device for evacuating the deposition chamber to a vacuum, a substrate holder for holding a substrate in the deposition chamber, and a heating device for heating the substrate. A thin film forming apparatus comprising: a gas introduction mechanism that introduces a source gas into the deposition chamber; a radiation light detection device that detects radiation light from the deposition surface of the substrate; and A thin film production apparatus comprising: a deposition start determination device that determines a deposition start time of a thin film. 11. The thin film production apparatus according to claim 10, wherein said radiation light detection device is a radiation thermometer. 12. A window through which radiation light to be detected can be transmitted is provided in the deposition chamber, and the radiation light detection device is disposed on the atmosphere side of the deposition chamber, and the radiation light transmitted through the window is emitted by the radiation light. The thin film production apparatus according to claim 10, wherein the detection is performed by a detection apparatus.