JPH07150352A - Film formation - Google Patents

Abstract

PURPOSE:To provide a film forming method with which films having high quality are obtd. by executing exact temp. monitor and control for a substrate in a vacuum and managing substrate temps. CONSTITUTION:Mirror finished surfaces 20 are installed near the surface to be formed with the films of wafers 10 prior to film formation placed on a calibration stage 5 and a substrate temp. control stage 6, by which the IR radiation characteristics of the wafers 10 under the film formation of the metallic films in the chamber 4 are simulated at the time of monitoring the temps. of the wafers 10 under process by measuring the radiation intensity from the wafers 10 by IR radiation thermometers 14, 15 in a chamber 4 for film formation by sputtering and a substrate temp. control chamber 3 for heating or cooling the wafers prior to the film formation. The radiation rate of the wafers 10 for later measurement of the radiation temps. of in the chambers 3, 4 is thereby previously determined in the calibration chamber 2. Namely, the correction value of the IR sensitivity necessary for IR temp. measurement during and after the film formation is previously obtd. and the exact temp. control of the substrates is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming method using a vacuum processing apparatus for performing various kinds of processing on a substrate in a vacuum, and in particular, a vacuum processing apparatus suitable for use in a semiconductor device manufacturing process. It relates to a membrane method.

[0002]

2. Description of the Related Art In a process apparatus used for manufacturing a semiconductor device, accurate control of a process temperature is important in order to realize well-controlled reactions. A typical process apparatus in which the temperature is the most important setting condition is a so-called furnace body such as an oxidation furnace. The inside of this type of furnace body is an oxidizing atmosphere in which the atmosphere is replaced. In this case, the substitution atmosphere is atmospheric pressure or higher, and the silicon wafer in the furnace body is heated by radiation from a heater installed around the quartz tube and heat conduction by the atmospheric pressure atmosphere in the quartz tube. . That is, since there is a medium that conducts heat, the temperature can be measured relatively accurately using a probe such as a thermocouple installed in the heat conducting atmosphere.

Further, as an example in which a heat-conducting medium is not used, there can be mentioned, for example, a photoresist baking apparatus used in a step of applying a photoresist used as a mask in an etching step. In this apparatus, baking is performed in an atmospheric pressure atmosphere, but the silicon wafer is placed on a heat block having a larger heat capacity than the silicon wafer heated to a predetermined baking temperature, and the silicon wafer is further provided on the heat block side. A vacuum chuck presses the entire surface of the silicon wafer against the heat block by atmospheric pressure. For this reason, the temperature of the wafer is balanced with the temperature of the heat block, so that the temperature of the wafer can be accurately controlled and managed by a temperature measuring element such as a thermocouple attached to the heat block. Many semiconductor manufacturing processes utilize highly pure materials and well-controlled reactions in a dust-free environment, and therefore often require processing in vacuum.

Conventionally, accurate temperature control of a wafer in a vacuum in a semiconductor manufacturing apparatus has been essentially difficult for the following reasons.

That is, in the heating by the lamp heater, since there is no medium for transmitting the heat, the wafer is heated only by the radiation, so that it is well known that only a small absorption occurs on the metal mirror surface and a large amount on the illuminator. Absorption occurs, and as a result, the degree of heating is greatly different depending on the surface state of the heated wafer.

Although attempts have been made to accurately measure the temperature of the wafer during the process by attaching the thermocouple to the wafer, thermocouples are used to measure the temperature of the wafer with the thermocouple in point contact with the wafer. It is difficult to stabilize the contact state at a constant level, and there are drawbacks that the measurement temperature is poor in reproducibility.

When the wafer is heated by infrared radiation, since the wafer is almost transparent in a wide range of the infrared region, heat is not transferred only to the thermocouple by conduction from the wafer, but the thermocouple itself. Accurate temperature measurement of the wafer is difficult because it may be heated by the lamp heater.

There is also a method of forcibly bringing a conductive medium into a vacuum. For example, as described in JP-A-56-48132 or JP-A-58-213434, a silicon wafer is clamped to a heat block installed in a vacuum atmosphere so that the back surface of the silicon wafer and the heat block are separated from each other. The temperature of the heat block is equilibrated with the temperature of the wafer by filling the gas with a pressure of about 1 Torr in the meantime. Also in this case, the temperature of the wafer can be controlled by a temperature measuring element such as a thermocouple attached to the heat block.

However, in this example, since the wafer is clamped to the heat block by a small force as compared with the use of the vacuum chuck under the atmospheric pressure, the temperature uniformity and reproducibility are not sufficient. The biggest drawback is that heat transfer from the heat block to the wafer takes time due to the low density of the heat transfer medium. Eventually, even if the heat block and the wafer reach thermal equilibrium, it takes several seconds to several tens of seconds as described in the above example,
Further, it is considered that various factors influence the reproducibility of the heat conduction time.

As described above, whichever heating means is used, it is necessary to measure the temperature of the wafer in vacuum without contact. As one of the methods, a method of measuring the radiation intensity from a wafer in the infrared region using an infrared thermometer has been proposed.

That is, according to this method, a wafer is placed on a heat stage in a sputtering apparatus and heated,
The temperature of the wafer is measured by an infrared thermometer through a through hole formed in a target placed facing the wafer. That is, the infrared emissivity of a wafer at a specific temperature is measured in advance by a calibration sample, and the wafer temperature during sputtering is controlled by the value.

As a technique related to this type of technique, there is, for example, Japanese Patent Laid-Open No. 1-129966.

[0013]

However, since the emissivity of the wafer is not always constant in this method as described below, accurate temperature measurement is difficult and there are some problems.

That is, a silicon wafer on which the same metal as the target material, for example, aluminum is deposited by several hundred Å is used as the calibration sample. Since the infrared emissivity from the wafer surface is different, the temperature control before film formation cannot be performed.

Further, even after the film formation is started, accurate temperature measurement cannot be performed until a film is formed to a certain thickness (for example, aluminum is 500 to 1000 Å).

In order to accurately measure the temperature of the wafer in vacuum and to control the temperature accordingly, the infrared emissivity of a wafer having the same metal film varies depending on the product lot. In the method of separately preparing a wafer for use, accurate temperature control cannot be performed because it is not the wafer on which the film is actually formed.

As described above, in the vacuum processing apparatus which has been conventionally used, although various temperature control means are used, none of them can accurately control the temperature of the process.

That is, the ideal method for controlling the temperature of a wafer using an infrared thermometer is to calibrate the infrared thermometer using the wafer itself on which the film is actually formed, and to irradiate the infrared radiation depending on the presence or absence of the film and its state. It is a method that can be measured without being affected by the difference in the rate. However, what has been put to practical use has not been proposed yet.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and an improved film forming method using a vacuum processing apparatus capable of accurately measuring and controlling the temperature of a substrate in a vacuum. To provide.

[0020]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present inventors conducted various studies as described below and obtained various findings.

That is, in the present invention, since the infrared radiation thermometer is used as a main temperature measuring means, calibration is performed for each substrate (eg, silicon wafer). Specifically, before processing the substrate by the target vacuum processing apparatus, heating or cooling is performed to a known temperature for each substrate in the stage in the temperature calibration chamber, and at one or more points of temperature, The temperature of the substrate is measured by the first infrared radiation thermometer. From the indicated value of the first infrared radiation thermometer obtained at this time, the infrared radiation thermometer in the vacuum processing chamber is corrected after the temperature calibration chamber. Specifically, the infrared radiation thermometer after the temperature calibration chamber is calibrated by knowing this correction value in advance, for example, a rough correction, or a simple coefficient if a narrow temperature range is targeted. In the case of having a plurality of temperature calibration points, there is a method of fetching each temperature calibration data into a computer and performing calculation for correction.

The temperature calibration chamber described above is not limited to a vacuum, but may be in an environment of atmospheric pressure. In an atmospheric environment, not only is the device structure generally simple,
It is possible to more easily bring the temperature of the target wafer closer to the temperature of the heat block (stage) heated or cooled to a known temperature.

Specifically, when the temperature calibration chamber is set under atmospheric pressure, it is possible to use a vacuum chuck on the stage to bring the base into close contact with a heat block having a larger heat capacity than the base. By doing so, the temperature of the substrate can be brought closer to the heat block temperature more accurately and in a short time.

When it is necessary to raise the temperature of the temperature calibration point, there is a problem that the surface of the target substrate is oxidized depending on the atmosphere. Therefore, the atmosphere of the temperature calibration chamber is replaced with the atmosphere. For example, a nitrogen or argon atmosphere is more preferable.

When the temperature calibration chamber is set under vacuum, in order to improve heat conduction between the heat block and the substrate as described above, heating or cooling gas is heated between them with a pressure of 5 Pascal or more. By interposing it as a conductive medium, the substrate temperature approaches the heat block in a relatively short time.

For example, in an apparatus for forming a thin film on a substrate by a sputtering method, when the substrate in the atmosphere is taken into the vacuum processing tank, the water adsorbed on the surface of the substrate is sufficiently removed. Therefore, it is necessary to heat the substrate to 150 ° C. or higher, and conversely, it is necessary to lower the temperature of the substrate that has already been heated to a film formation start temperature of about 50 ° C. in the vacuum chamber. There are cases such as In the case of raising and lowering the temperature, it is necessary to accurately measure the temperature each time the temperature is controlled, and it is necessary to calibrate the temperature of each infrared radiation thermometer for each substrate in advance. That is, before performing a predetermined vacuum treatment, the substrate is heated or cooled to a known temperature in advance, the temperature of the substrate is measured by the first infrared radiation thermometer, and it is used in the subsequent vacuum treatment process based on the measurement result. If a film-forming apparatus that has the function of calibrating one or more second infrared radiation thermometers and that needs to accurately control the temperature of the substrate, such as a sputtering apparatus or a CVD apparatus, is used, A process suitable for parts can be realized.

The above-mentioned measurement by the first and second infrared radiation thermometers can be carried out at the same wavelength in the infrared region to enable more accurate calibration.

When the first infrared radiation thermometer at a known temperature is calibrated with a heated substrate, if heating to a known temperature is performed in a vacuum, water adsorbed on the substrate can be removed. Since it can be combined with the so-called baking treatment, the apparatus scale can be reduced, which is preferable in some cases.

For example, when the temperature of the substrate is raised in the vacuum processing chamber of the sputtering apparatus, if the infrared radiation thermometer is calibrated beforehand, radiant heating by a lamp can be performed instead of using a heat block, A cheaper sputtering apparatus can be constructed.

When the lamp heating is used in the vacuum processing chamber, since the light of the lamp may enter the infrared radiation thermometer as stray light, the measurement wavelength of the infrared radiation thermometer is different from the wavelength radiated by the lamp. It is essentially preferable that the wavelength range is different.

When a silicon wafer is used as the substrate, for example, since the silicon wafer is almost transparent in the infrared region, an infrared lamp containing quartz glass, which is generally widely used, cannot perform efficient heating. Further, since an infrared lamp of this kind is likely to become stray light with respect to the infrared radiation thermometer, it is more preferable to use a lamp having a short wavelength with a high absorption efficiency of a silicon wafer.

When the temperature at which film formation on the substrate is started in the vacuum processing chamber is lower than the baking heating temperature in vacuum for removing the adsorbed moisture from the substrate, after baking is performed. Therefore, it is necessary to cool the substrate to a predetermined temperature in the vacuum chamber and adjust the substrate to a predetermined film formation start temperature. In order to realize such a film forming process with high accuracy, a stage equipped with a first infrared radiation thermometer for performing temperature calibration in the temperature calibration chamber, and a stage for baking the substrate in vacuum , A stage for cooling to a temperature at which a predetermined film formation is started before further film formation,
Then, a sputtering apparatus is required which is capable of accurately measuring the substrate temperature on the cooling stage by calculating and using the correction value obtained by the first infrared radiation thermometer.

In order to observe the substrate with an infrared radiation thermometer, it is necessary to provide a through hole (opening window) for observation in the heating or cooling stage, which causes nonuniformity in the temperature distribution of the substrate. Sometimes. In this case, the stage is divided into two in the same chamber and both are adjusted to have the same temperature, that is, one heating or cooling stage has an opening window for observing the substrate temperature by an infrared radiation thermometer. It is possible to reduce such non-uniformity by providing an opening window on the other temperature measuring stage without providing it, and immediately transporting the substrate to the other stage after heating or cooling on one stage to measure the temperature. it can.

By providing a plurality of temperature calibration points, it is possible to control the process temperature more accurately, but by providing a plurality of heating means or cooling means in the substrate temperature calibration chamber, calibration at a plurality of temperatures can be made shorter. Can be done in time.

Further, in the case of an apparatus for forming a metal film by sputtering, since the infrared ray radiated to the surface opposite to the surface on which the metal film formed on the substrate is observed is reflected, a shutter as will be described later is provided. If there is no film, the size of the radiation incident on the infrared radiation thermometer differs depending on the presence or absence of the film, and the apparent infrared emissivity differs, but to the surface of the substrate opposite to the surface observed by the infrared radiation thermometer due to the shutter. Since most of the radiated infrared rays are reflected, the apparent difference in infrared emissivity before and after film formation can be significantly reduced.

In the stage for heating or cooling the substrate, the substrate is close to the surface on the opposite side of the surface observed by the infrared radiation thermometer through the opening window of the stage, and is sufficient for the measurement wavelength of the infrared radiation thermometer. By arranging the shutter mechanism whose main surface is composed of a member which is a mirror surface, it is possible to block stray light penetrating the base body and entering the infrared radiation thermometer.

The present invention has been made based on the above findings. The means for achieving the object will be specifically described below. The purpose is to control the temperature of a substrate to be subjected to a film-forming treatment. A method for forming a film on a substrate, comprising:
Before the film forming process, a process in which the infrared radiation characteristic exhibited by the substrate during and after the film forming process is artificially generated, and the radiation intensity of the substrate at a known temperature is measured by a first infrared radiation thermometer, In order to correctly obtain the temperature of the substrate by the second infrared radiation thermometer from the output of the first infrared radiation thermometer that measured the radiation intensity from the substrate in the pseudo state based on the known temperature. And storing the infrared sensitivity correction value in the storage means, and during and after the film formation process of the substrate to be measured under unknown temperature conditions, the radiant intensity of the substrate is changed to the second infrared radiation. The step of measuring with a thermometer and the output from the second infrared radiation thermometer for measuring the radiation intensity of the substrate are corrected based on the infrared sensitivity correction value obtained in advance to determine the true temperature of the substrate. calculate And degree, according to the temperature that the calculated,
It is achieved by a film forming method including a step of controlling the temperature of a substrate and performing a film forming process.

Preferably, before the film forming process, a step of quasi-inducing the infrared radiation characteristics exhibited by the substrate during and after the film forming process is performed on the surface of the substrate on which the film forming process is performed. That is, the step of bringing the member, which substantially constitutes the mirror surface, close to the measurement wavelength of the first infrared radiation thermometer.

[0039]

In the temperature calibration chamber, the substrate is heated or cooled to a known temperature and the temperature of the substrate is measured by the first infrared radiation thermometer and the thermocouple before the substrate is subjected to the predetermined treatment in the vacuum processing chamber. The measurement is performed, and the correction value of the infrared radiation thermometer, that is, the emissivity is calculated based on the measurement result.
Based on the calculation result, the temperature of the substrate in the vacuum processing chamber thereafter is accurately measured by the second and third thermometers. Then, based on the measurement result, the temperature control system is operated to set the temperature of the substrate in the vacuum processing chamber to a predetermined value, and vacuum processing such as film forming processing is performed in a precisely temperature-controlled state.

In the temperature calibration chamber, the first
By performing calibration temperature measurement with infrared radiation thermometer and thermocouple at different temperatures, it is possible to control the process temperature in a wide temperature range in the subsequent temperature control of the substrate in the vacuum processing chamber. It will be possible.

Further, by providing a plurality of means as heating means or cooling means for measuring the calibration temperature by the above-mentioned first infrared radiation thermometer and thermocouple, calibration by a plurality of different temperatures can be performed in a shorter time. It can be carried out.

In order to observe the substrate with an infrared radiation thermometer during heating or cooling of the substrate, it is necessary to provide a through hole (opening window) in the heating or cooling stage. The distribution may be non-uniform. Therefore, as a countermeasure against this, it is possible to heat both the front and back sides of the substrate, but the stage is divided into two, and one of the substrate heating or cooling stages is not provided with an opening window and is a stage dedicated to temperature control, and the other is The temperature measuring stage may be provided with an opening window, and the temperature may be measured by moving the substrate from the one stage to the other stage in the temperature measurement.

In the present invention, disposing the shutter close to the substrate when measuring the temperature of the substrate plays a very important role in accurately measuring the temperature of the substrate. The first role is that, in the case of a device for forming a metal film by sputtering or CVD, regardless of the presence or absence of the metal film, the same infrared emissivity as that of the metal film formed by this shutter is obtained. Since it can be obtained, it is possible to correct the apparent difference in infrared emissivity before and after film formation, and to enable correct temperature control of the substrate based on accurate temperature measurement. The second role is The purpose is to block stray light penetrating the substrate and entering the infrared radiation thermometer to prevent measurement errors due to stray light.

This shutter mechanism is indispensable especially for measuring the temperature of the substrate before film formation. It should be noted that other actions that could not be described here will be specifically described in the section of the embodiment.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Example 1 FIG. 1 is a schematic configuration diagram showing an example in which the vacuum processing apparatus of the present invention is applied to a sputtering film forming apparatus. In this example, a silicon wafer is used as a film formation target, and an example of forming an Al thin film on the silicon wafer by sputtering will be described as a typical example.

The vacuum processing apparatus 1 of the present invention comprises a substrate temperature calibration chamber 2 having a substrate temperature calibration stage 5, a substrate temperature adjustment chamber 3 having a substrate temperature adjustment stage 6 for heating and cooling the substrate, and sputtering film formation. It is composed of three chambers, a stage 7, an Al target 8 and a sputtering film forming chamber 4 having a sputtering electrode 9. And these chambers are gate valves GV1 and GV, respectively.
It is connected by V2 and is independent.

Further, an exhaust system is connected to the substrate temperature calibration chamber 2 and the sputtering film forming chamber 4 so that a predetermined vacuum state can be maintained on the one hand and a predetermined gas is introduced from a gas introduction port on the other hand. In the temperature calibration chamber 2, air or nitrogen gas can be introduced to set the atmospheric pressure,
The sputtering film forming chamber 4 is configured so that it can be set in an environment in which a sputtering gas is introduced and plasma is generated by a predetermined discharge.

Furthermore, each stage is provided with heating and cooling means as will be described later, and an opening window 19 consisting of a through-hole for observing radiant infrared rays from the substrate 10 is provided. The first, second and third infrared radiation thermometers 1 are optically coupled through this opening window 19
1, 14, and 15 are connected. The base temperature calibration stage 5 is provided with a thermocouple 12 for accurately measuring the temperature of the base temperature calibration stage 5. Then, the output from each infrared radiation thermometer and the output of the thermocouple 12 are input to calculate the emissivity of the first infrared radiation thermometer 11, and the second and third infrared radiation are calculated based on the calculation result. The thermometers 14 and 15 are corrected to measure the correct temperature of the substrate 10 on each stage, and finally a command to set a predetermined stage temperature based on these measurement data is used to heat and cool each stage. A substrate temperature controller 13 for controlling the temperature of the so-called vacuum processing apparatus by feeding back to the means and setting and controlling the temperature of the stage to a predetermined value is provided.

To explain the function of each chamber, the substrate temperature calibration chamber normally uses the first infrared radiation thermometer 11 to detect infrared radiation from the substrate 10 set to a known temperature higher than the film formation start temperature. This infrared radiation thermometer is calibrated by measuring and calculating the emissivity. The substrate temperature adjusting chamber 3 has a temperature adjusting function before the substrate is transferred to the next sputtering film forming chamber 4, and the sputtering film forming chamber 4 has a function of forming a film on the substrate by sputtering.

The substrate 1 is controlled by controlling the temperature of each stage below.
A specific example in which 0 is held at a predetermined temperature and an Al thin film is sputtered from the Al target 8 on the silicon wafer substrate 10 will be described.

First, in the substrate temperature calibration chamber 2 under atmospheric pressure, the wafer 10 is gradually heated on the calibration stage 5 to three temperature points of 200 ° C., 300 ° C. and 400 ° C. In addition, heating at these stages 5, 6, and 7,
The cooling method will be collectively described later.

Substrate 1 heated on this calibration stage 5
On the back side of 0, the first infrared radiation thermometer 11 and the thermocouple 12
Are observed and measured, and the instruction value of the temperature at each temperature step is obtained by the arithmetic processing unit of the substrate temperature controller 13. That is, the thermocouple 12
The temperature of the calibration stage, which is parallel to the substrate temperature, is actually measured, and the emissivity at that time is observed with the infrared radiation thermometer 11 as the substrate temperature, and this radiation is performed by the arithmetic processing unit of the substrate temperature controller 13. Obtain a temperature-based reading based on the rate.

Since the wafer 10 has been heated to a known temperature in advance, the emissivity obtained from the first infrared radiation thermometer 11 can be obtained by back-calculation. This emissivity is used for the processing temperature of the temperature adjustment chamber 3 and the sputtering film formation chamber 4,
The emissivity is corrected and read from the third infrared radiation thermometers 14 and 15.

When the emissivity calibration by the first infrared radiation thermometer 11 is completed, the substrate temperature calibration chamber 2 is evacuated to a vacuum state, and then the wafer 10 opens the gate valve GV1 to calibrate the chamber. 2 to the substrate temperature adjusting chamber 3 under vacuum, and the second infrared radiation thermometer 1
The temperature is measured according to 4. Based on the measurement result, the temperature of the stage 6 is adjusted by the substrate temperature controller 13, and the wafer 1
Adjust the temperature of 0 to any temperature. In this example, 100
It was set to ℃. After that, the wafer 10 becomes
V2 is opened and the film is transferred to the stage 7 of the sputtering film forming chamber 4 in a vacuum state, the temperature is measured by the third infrared radiation thermometer 15, and the temperature of the stage 7 is adjusted to an arbitrary temperature based on the result, Film formation by sputtering is performed by controlling the temperature of the substrate 10 to an arbitrary temperature. In this example, the temperature was set to 250 ° C. and the Al film was formed by sputtering. After the sputter film formation, the wafer 10 was again transported to the calibration chamber 2 to recalibrate the emissivity, and this emissivity was used for correction during the temperature measurement during the subsequent sputter film formation. As a simple means for transporting between the chambers, for example, a transport mechanism using a heat resistant belt made of silicone rubber or the like is used.

Next, referring to FIG. 2, an outline of the structure of the stage on which the substrate is mounted, a heating and cooling method, and a method for measuring the emissivity of the wafer will be described using an example of the sputtering stage 7.

(1) Substrate stage structure and heating / cooling method: The sputtering stage 7 has a built-in electrothermal heater 18 for heating the stage and transfers heat to the wafer in vacuum. For example, air or nitrogen gas is used. It has a structure in which the heat transfer gas flows, and a clamp 17 for bringing the heat transfer gas into uniform contact with the wafer is installed. Further, there is provided an opening window 19 which constitutes a radiation observation cavity for measuring the temperature of the wafer by the infrared radiation thermometer 15. When the wafer is cooled, although not shown, a cooling medium such as Freon is circulated instead of the heater 18 to cool the stage,
Similar to the above, the wafer is cooled by the heat transfer gas.

Further, in the calibration stage 5, since the chamber is at atmospheric pressure, the heat transfer gas is not used and the chamber is evacuated, and the vacuum chuck keeps the close contact with the stage to transfer heat by heat conduction. .

(2) Measurement of emissivity: Next, a method of measuring the temperature of the wafer substrate with an infrared radiation thermometer will be described.
In this embodiment, infrared radiation thermometers 11, 14 and 15 are installed at the bottom of each stage to set the temperature on the back side of the wafer, so that stray light from inside each chamber does not enter the infrared thermometer. As described above, the stray light blocking cylinder 16 is provided between each stage and the infrared radiation thermometer.

In this embodiment, the treatment in vacuum is film formation of Al on the substrate by sputtering. When the base body receives the Al metal film, the emissivity is significantly increased by the amount of reflection from the Al film. Therefore, the emissivity obtained by measuring the film formation process in the substrate temperature calibration chamber cannot be used in the subsequent film formation process.

In the present invention, the wafer after the film forming process is heated again in the calibration chamber to a preset known temperature, and the emissivity is measured again for a new surface to perform recalibration. As a result, for example, by measuring the wafer immediately after the film formation with an infrared radiation thermometer and calculating the correct emissivity by the emissivity measurement (second time) after the film formation, the wafer temperature immediately after the film formation can be accurately measured. It is possible to know.

For example, when the temperature of the wafer immediately after the film formation is too high, the heating condition setting is changed so as to reduce the substrate heating amount performed during the film formation or before the film formation.

When it is desired to lower the temperature just after the film formation is completed without changing the set temperature at the start of film formation, the gas is cooled on the substrate stage and the gas pressure on the back surface of the substrate is adjusted. The setting for cooling the substrate during film formation can be changed during film formation.

In the above embodiment, the silicon wafer is used as the substrate and the Al thin film is formed on the back surface by sputtering. However, since the temperature of the substrate can be controlled with high accuracy through the stage, the reproducibility within the wafer is improved. A good crystallinity was obtained and a high quality film could be achieved.

Example 2 When a metal film is formed on the opposite side of the substrate 10 observed by an infrared radiation thermometer, the apparent infrared emissivity value may vary greatly depending on the presence or absence of the film. FIG. 3 shows an example in which a second temperature calibration chamber 32 is added to the sputtering deposition chamber 4 of FIG. 1 in order to calibrate the infrared emissivity of the substrate after deposition in the sputtering apparatus for such a purpose. Is shown.

The temperature of the substrate is measured by the infrared radiation thermometer 15 during film formation by sputtering. However, in this case, since the metal film is already formed on the surface of the substrate 10, the correction value of the infrared emissivity obtained in the substrate temperature calibration stage 2 cannot be used. For this purpose, after sputtering film formation, the substrate 10 is transported from the sputtering film formation chamber 4 to the second temperature calibration chamber 32, and heated or cooled to a predetermined temperature by the heating or cooling stage 33 as in the temperature calibration chamber 2, Infrared radiation thermometer 3
4 and the thermocouple 35, the temperature is measured, and the infrared emissivity of the substrate 10 after film formation at a predetermined temperature is calculated from the indicated values of both. By correcting the temperature data obtained during film formation with this value, the temperature of the substrate during film formation can be accurately known. If the temperature of the substrate 10 during film formation obtained in this way is higher than a predetermined value, the heating means or the cooling means of the substrate temperature adjusting chamber 3 is appropriately adjusted to properly adjust the temperature of the substrate. By applying the feedback, the film forming process for the next substrate can be properly performed.

The temperature calibration chamber for calibrating the infrared emissivity of the substrate after film formation is not necessarily the temperature calibration chamber 2 for calibrating the infrared emissivity of the substrate before film formation as in this example. It is not necessary to prepare it separately. That is, after forming a film in the sputter film forming chamber 4, the substrate is again passed through the substrate temperature adjusting chamber 3 and the temperature calibration chamber 2
Alternatively, the infrared emissivity may be calibrated here similarly to the second temperature calibration chamber 32.

<Embodiment 3> In the above Embodiments 1 and 2, the emissivity of the substrate changed when the substrate was subjected to film formation, so it was necessary to calibrate the emissivity again. By improving this point, it is possible to correct the infrared radiation thermometer with this emissivity as a reference even in the subsequent film forming process by once calibrating the emissivity.

This embodiment also describes an example of an apparatus for forming aluminum Al on a silicon wafer substrate by sputtering similarly to the first embodiment.

FIG. 4 shows a schematic configuration diagram of a sputtering apparatus, which is basically the same as that of FIG. 1, but in this example, as will be described later in detail, the substrate 10 mounted on each stage is mounted on the substrate 10. That is, the shutters 20, 21, and 22 are arranged close to each other.

The substrate 10 is first heated or cooled in the temperature calibration chamber 2 to a predetermined temperature by the heating or cooling stage 5, the temperature is measured by the first infrared radiation thermometer 11 and the thermocouple 12, and the indicated values of both are measured. From this, the infrared emissivity of the substrate 10 at a predetermined temperature is calculated. When a metal film is formed by sputtering on the side of the substrate opposite to the side observed by the infrared thermometer, the apparent infrared emissivity value may differ greatly depending on the presence or absence of the film. The difference in apparent infrared emissivity due to the presence or absence can be reduced.

The infrared radiation thermometer 11 is measured with the shutter 20 closed.

Next, the substrate 10 is transferred from the temperature calibration chamber 2 to the substrate temperature adjusting chamber 3, and the temperature of the substrate 10 is measured by the second infrared radiation thermometer 14 while being heated or cooled by the heating or cooling stage 6. The temperature of the heating or cooling stage 6 is adjusted to a predetermined temperature through the substrate temperature controller 13 by correcting the value of the emissivity of the substrate 10 at the predetermined temperature obtained in the calibration chamber 2, and the temperature of the substrate 10 is set to the predetermined temperature. Control to the temperature of. As with the temperature calibration chamber 2, the thermometer side of the substrate temperature adjusting chamber 3 is also measured with the shutter 21 closed.

After that, the substrate 10 is formed by the sputtering film forming chamber 4
And is heated or cooled on the sputtering stage 7. At this time, the shutter 22 is closed on the substrate, the temperature of the substrate 10 is measured by the third infrared radiation thermometer 15, and the correct temperature is known by the correction with the emissivity value of the substrate 10 obtained by the calibration chamber 2. You can Further, by knowing the correct temperature in this way, the substrate temperature controller 1
3, the temperature of the heating or cooling stage 7 is adjusted to a predetermined temperature, the temperature of the substrate 10 is controlled to a predetermined temperature, and sputter film formation is started. After the film formation is completed, the substrate 10 is returned to the substrate temperature adjusting chamber 3, and the temperature is measured by the second infrared radiation thermometer 14 while being heated or cooled by the stage 6. At this time, by correcting the value of the emissivity of the substrate at the predetermined temperature obtained in the calibration chamber 2, the temperature of the stage 6 is adjusted to the predetermined temperature through the substrate temperature controller 13 and the substrate temperature is set to the predetermined value. To do. After that, the substrate is carried out of the vacuum processing apparatus 1 through the temperature calibration chamber 2 and proceeds to the next step.

The temperature of the substrate 10 is measured by the first infrared thermometer 11 and the thermocouple 12 in the substrate temperature calibration stage 2 at a plurality of temperatures, and the second and third infrared radiation thermometers 14 and 15 are used. The use enables more precise control of the process temperature. Although not shown, by providing a plurality of means for heating or cooling the substrate for measuring with the first infrared radiation thermometer 11 for calibrating the substrate temperature, the temperature of the substrate at a plurality of similar temperatures can be measured. Calibration can be performed in a shorter time.

FIG. 5 shows a schematic configuration diagram of the sputtering stage 7 of FIG. 4 as a typical example of the stage. The structure of the stage is basically the same as that of the example shown in FIG. 2, but the present embodiment is different in that a shutter 22 is provided in the vicinity of the upper portion of the substrate 10.

That is, when a metal film is formed by sputtering on the side of the substrate opposite to the side observed by the infrared thermometer,
The value of the apparent infrared emissivity may vary greatly depending on the presence or absence of the film, but the installation of this shutter can reduce the difference in the apparent infrared emissivity due to the presence or absence of the film.
As shown in FIG. 3, it is not necessary to perform the measurement by the infrared thermometer for temperature calibration twice before and after the film formation by disposing the second temperature calibration chamber 32, and the measurement can be performed once.

This shutter has a mechanism that closes the surface of the substrate during temperature measurement and is opened and closed during film formation. For example, a stainless steel disk is supported by a rotatable drive shaft, It is configured to open and close by rotating the shaft.

Further, since the silicon wafer substrate 10 is almost transparent to infrared rays, stray light may penetrate the substrate and enter the infrared radiation thermometer to lower the temperature measurement accuracy of the substrate. As a countermeasure against this, in this example, a shutter 22 is formed on the side opposite to the side observed by the infrared thermometer, close to the substrate, and whose main surface is constituted by a member which is sufficiently a mirror surface for the measurement wavelength of the infrared radiation thermometer. Is provided so that the stray light is blocked during the temperature measurement of the substrate 10 by the infrared radiation thermometer 15.

As described above, the role of the shutter mechanism is first to correct the increase in the apparent emissivity due to the radiated light from the wafer which is reflected by the metal film when the metal film is formed on the wafer base. The second is blocking of stray light.

FIG. 6 shows a schematic block diagram of the stage 6 shown in FIG. 4, which is basically the same as the stage 7 shown in FIG. The stage 6 has a heater 18 built-in, and has a structure in which the heat transfer gas flows in the space between the stage 6 and the base body 10 in vacuum, and a clamp 17 for uniformly contacting the heat transfer gas with the base body is provided. is set up. Base 1
An open window 19 for measuring a temperature of 0 with an infrared radiation thermometer 14 and a stray light blocking cylinder 16 are connected to each other.
Window plates 23 and 24 made of a material that transmits infrared rays are attached to both ends of 6. Further, the cylinder 16 itself is water-cooled so that it is not heated and does not become a source of stray light. To further reduce the effect of stray light, it is possible to process the inner wall of the cylinder 16 with a black body. Also in this example, as in the case of FIG.
Is provided.

The shutter may have any structure as long as (1) it has a mirror surface state having the same infrared reflectance as the deposited metal film, and (2) it has a function of blocking stray light. Various structures can be adopted, such as a structure in which the shutter is opened and closed in synchronization with the temperature measurement timing, or a fixed shutter is provided in one region of the chamber and the substrate is moved to the lower part of the shutter during measurement.

FIG. 7 is a characteristic curve showing the difference in the infrared emissivity of the silicon wafer substrate with and without the shutter.
FIG. 7A is a comparative example without a shutter, and FIG. 7B is a comparative example.
The measurement result of the present example in which a shutter is provided is shown. As apparent from this, the apparent infrared emissivity of the wafer before the aluminum Al film formation (without Al film) in FIG.
Although the infrared emissivity is smaller than the apparent infrared emissivity of the wafer after the film formation (with the Al film), there is a considerable difference between the two, but by installing a shutter on the wafer before the Al film formation,
As shown in (b), it was found that the apparent infrared emissivity was almost the same as that of the wafer after Al film formation. From this, it is understood that the measurement of the substrate temperature using the shutter enables measurement with a constant emissivity.

<Embodiment 4> When the temperature distribution of the substrate becomes non-uniform due to the opening window 19 for measuring the infrared temperature of the substrate on the heating or cooling stage, a through hole (opening window) is formed as shown in FIG. After heating or cooling the substrate 10 by a stage 25 dedicated to heating or cooling provided separately in a place apart from 19, the substrate 10 is transported to a stage having an opening window 19 and temperature is measured by an infrared radiation thermometer 27. With such a configuration, the temperature distribution of the substrate 10 can be measured in a more uniform state.

<Embodiment 5> When the substrate is heated or cooled only from either the front surface or the back surface, a temperature difference occurs between the front surface and the back surface of the substrate. Therefore, as shown in FIG. 9, heating or cooling means 28, 2 is provided on each side so that the temperature can be controlled from both sides of the front surface and the back surface of the substrate.
By providing 9, the temperature difference between both surfaces can be reduced. Further, this can also reduce the non-uniformity of the temperature distribution on the substrate due to the opening window 19.

<Embodiment 6> Another embodiment of forming an aluminum Al film on the silicon wafer substrate 10 by sputtering using the sputtering apparatus 1 shown in FIG. 4 will be described.

The silicon wafer substrate 10 is heated to 500 ° C. in the temperature calibration chamber 2 to remove adsorbed moisture and the like, and the temperature is measured by the thermocouple 12, and the emissivity of the infrared radiation thermometer 11 is calibrated based on this. Then, the wafer is transferred to the substrate temperature adjusting chamber 3. The temperature of the wafer substrate 10 transferred to the substrate temperature adjusting chamber 3 is measured by the infrared radiation thermometer 14, cooled to a predetermined temperature of 200 ° C. by the temperature control of the stage 6, and transferred to the sputtering film forming chamber 4. The substrate 10 is sputtered in the sputter deposition chamber 4 according to the temperature profile shown in FIG. Target 8 is 1% Si-3% Cu-
An Al composition was used. First of all, the temperature of the substrate 10 is controlled to 230 ° C., and the first film thickness of about 100 Å
Sputter film formation of, sputter is stopped there,
The substrate is transferred to the substrate temperature adjusting chamber 3. In the substrate temperature adjusting chamber 3, the temperature of the substrate 10 is heated and controlled to 300 ° C., and the crystal grains of the Al film obtained by the first sputter deposition are grown to improve the orientation and the like. Next, the substrate is again transported to the sputtering film forming chamber 4, and after setting the substrate temperature to about 400 ° C., the second sputtering film formation is restarted to form a film having a film thickness of about 1 μm. As a result, an Al sputtered film having large crystal grains and good orientation can be obtained. After the sputtering is completed, the substrate is immediately transferred to the substrate temperature adjusting chamber 3 and rapidly cooled to about 50 ° C. As a result, the protrusion of Si and Cu in the Al sputtered film could be suppressed.

In the above-mentioned embodiment, an example is shown in which a silicon wafer is used as a substrate and an Al thin film is formed on the surface by sputtering. However, since the temperature of the substrate can be controlled with high accuracy via the stage, reproducibility within the wafer is improved. A good crystallinity was obtained, and a film with excellent quality could be achieved. For example, when heating a thin film of several hundred liters at a heating temperature of 350 ° C. or higher, no improvement in crystallinity was obtained. Therefore, such a film forming method cannot be industrially realized without the present invention capable of knowing an accurate temperature.

In addition to the above-mentioned sputtering apparatus, the vacuum processing apparatus of the present invention is a CVD (Chemicai Vapor Depositi).
It is needless to say that it can be applied to a film forming apparatus etc.

For example, it is effective when a silicon wafer substrate is used as a substrate and a tungsten film is formed on this substrate by a known method by CVD.

In any of the film forming apparatuses of this type, the accuracy of the temperature control of the substrate influences the quality of the film formed, and therefore the film forming apparatus of the present invention can sufficiently meet such requirements.

Although the film forming apparatus can be realized by using the vacuum processing chamber as the film forming processing chamber as in the above-described embodiment, the vacuum processing chamber is not limited to the film forming chamber but may be dry etching processing such as plasma etching. It is also possible to use the above chamber, and the temperature control of the substrate to be etched can be easily realized as in the above embodiment.

[0093]

As described above, according to the present invention, it is possible to accurately control the temperature of a substrate in a vacuum, and before and after film formation, which requires accurate temperature control,
Also, since the temperature during film formation can be easily controlled, a high quality film can be formed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional block configuration diagram for schematically explaining a vacuum processing apparatus showing an embodiment of the present invention.

FIG. 2 is a schematic sectional configuration diagram showing an example of a sputtering stage.

FIG. 3 is a partial cross-sectional block diagram for schematically explaining a vacuum processing apparatus showing another embodiment of the present invention.

FIG. 4 is a schematic partial cross-sectional block configuration diagram of a vacuum processing apparatus showing still another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional configuration diagram showing an example of a sputtering stage and a substrate temperature adjusting stage each provided with a shutter mechanism.

FIG. 6 is a schematic cross-sectional configuration diagram showing an example of a sputtering stage and a substrate temperature adjusting stage each provided with a shutter mechanism.

FIG. 7 is a characteristic curve diagram showing temperature measurement results with and without a shutter.

FIG. 8 is a sectional view of a stage according to another embodiment of the present invention in which the stage is divided into two in the same chamber.

FIG. 9 is a cross-sectional view of a stage in which temperature control means is provided on both surfaces of a base.

FIG. 10 is an explanatory diagram showing one temperature profile during film formation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum processing apparatus, 2 ... Substrate temperature calibration chamber, 3 ... Substrate temperature adjustment chamber, 4 ... Sputter deposition chamber, 5 ... Substrate temperature calibration stage, 6 ... Substrate temperature adjustment stage, 7 ... Sputter stage, 8 ... Target, 9 ... Sputtering electrode, 10 ... Substrate, 11, 14, 15 ... Infrared radiation thermometer, 13 ... Substrate temperature controller, 16 ... Stray light blocking cylinder, 19 ... Open window, 20-22 ... Shutter, GV1, GV2 ... Gate valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Shimamura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Hitachi, Ltd. Institute of Industrial Science (72) Inventor Susumu Taketake 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Address Company, Hitachi, Ltd., Production Engineering Laboratory (72) Inventor, Eisuke Nishitani, 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture, Ltd., Production Company, Hitachi, Ltd. (72) Yuji Yoneoka Yoshida, Totsuka-ku, Yokohama, Kanagawa Prefecture 292, Machi Incorporated company Hitachi, Ltd.

Claims (2)

[Claims] 1. A film forming method in which a substrate to be subjected to a film forming process is temperature-controlled to perform a film forming process on the substrate, wherein the substrate is in a film forming process and before the film forming process. From the substrate in the pseudo state based on the known temperature, which causes a pseudo infrared radiation characteristic to be presented later and measures the radiation intensity of the substrate at a known temperature with a first infrared radiation thermometer. Calculating an infrared sensitivity correction value for correctly acquiring the temperature of the substrate by the second infrared radiation thermometer from the output of the first infrared radiation thermometer which has measured the radiation intensity of And, during and after the film forming process of the substrate to be measured under an unknown temperature condition,
The step of measuring the radiation intensity of the substrate by the second infrared radiation thermometer and the output from the second infrared radiation thermometer for measuring the radiation intensity of the substrate are the infrared sensitivity correction values obtained in advance. A film forming method comprising: a step of correcting the temperature based on the above to calculate a true temperature of the substrate; and a step of carrying out a film forming process by controlling the temperature of the substrate according to the calculated temperature. 2. Prior to the film forming process, a step of imitating infrared radiation characteristics exhibited by the substrate during and after the film forming process is simulated on the surface of the substrate on which the film forming process is performed. 1
The film forming method according to claim 1, which is a step of bringing a member that substantially forms a mirror surface close to a measurement wavelength of the infrared radiation thermometer.