JPH10140349A - Film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film formation method which make it possible to obtain films having good quality by executing the exact temp. monitor and control of substrates in vacuum and managing substrate temps. SOLUTION: The temp. of a wafer 10 under process is monitored by measuring the radiation intensity from the wafer 10 by IR radiation thermometers 14, 15 in a sputtering film forming chamber 4 and a substrate temp. control chamber 3 for heating or cooling the wafer prior to film formation. At this time, a mirror finished surface 20 is installed in proximity to the surface to be formed with the film of the wafer 10 before film formation placed on a calibration stage 5 and a substrate temp. control stage 6, by which the IR radiation characteristics exhibited by the wafer 10 under the metallic film formation in a chamber 4 are simulated. The radiation rate of the wafer 10 for later radiation temp. measurement in the chambers 3, 4 is thereby determined beforehand in a calibration chamber 2. Namely, the IR sensitivity correction value necessary for the IR temp. measurement during and after the film formation is previously acquired and the substrate is exactly subjected to the temp. management.

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 processes on a substrate in a vacuum, and more particularly to a method using 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, it is important to accurately control a process temperature in order to realize a well-controlled reaction or the like. A representative example of a process apparatus in which the temperature is the most important setting condition is a so-called furnace such as an oxidation furnace. The inside of this kind of furnace is an oxidizing atmosphere replaced with the atmosphere. In this case, the replacement atmosphere is at or above atmospheric pressure, and for example, a silicon wafer in the furnace body is heated by radiation from a heater installed around a quartz tube and heat conduction by the atmospheric pressure atmosphere in the quartz tube. . That is, since there is a medium for conducting heat, the temperature can be measured relatively accurately using a measuring element such as a thermocouple installed in the heat conducting atmosphere.

Further, as an example in which a heat conductive medium is not used, a photoresist baking apparatus used in a step of applying a photoresist used as a mask in an etching step can be exemplified. 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 a silicon wafer heated to a predetermined baking temperature, and the silicon wafer is further provided on the heat block side. The entire surface of the silicon wafer is pressed against the heat block by atmospheric pressure using a vacuum chuck. Therefore, 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 rely on highly pure materials and well-controlled reactions in a dust-free environment, often requiring processing in a 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, the wafer is heated only by the radiation because there is no medium for transmitting heat, and therefore, as is well known, 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 varies greatly depending on the surface condition of the heated wafer.

Attempts have been made to accurately measure the temperature of the wafer during the process by attaching a thermocouple to the wafer. However, in order to measure the temperature of the wafer while the thermocouple is in point contact with the wafer, the temperature of the thermocouple is measured. It is difficult to stabilize the contact state to a constant level, and the measurement temperature has a drawback of poor reproducibility.

When a wafer is heated by infrared radiation, since the wafer is almost transparent in a wide range of the infrared region, heat is not transmitted to the thermocouple only by conduction from the wafer, but the thermocouple itself is heated. In some cases, the wafer may be heated by a lamp heater, and it is difficult to accurately measure the temperature of the wafer.

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 set in a vacuum atmosphere, and the back surface of the silicon wafer is connected to the heat block. By filling the gas with a pressure of about 1 Torr in between, the temperature of the wafer is equilibrated with the temperature of the heat block. Also in this case, the temperature of the wafer is measured 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 with a small force as compared with the use of a vacuum chuck under atmospheric pressure, the uniformity and reproducibility of the temperature are not sufficient. The biggest disadvantage is that the heat transfer medium 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, the temperature of the wafer must be measured in a non-contact manner in a vacuum. As one of the methods, there has been proposed a method of measuring a radiation intensity from a wafer in an infrared region using an infrared thermometer.

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

[0012] Japanese Patent Application Laid-Open No. 1-129966 can be cited as one related to this kind of technology.

[0013]

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

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

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

In order to perform accurate temperature measurement of a wafer in a vacuum and the accompanying temperature control, even if a wafer on which the same metal film is formed has a different infrared emissivity depending on the product lot, calibration is performed as in this example. In a method in which a separate wafer is prepared, accurate temperature control cannot be performed because the wafer is not a wafer on which a film is actually formed.

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

That is, an ideal method of 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 determine whether or not there is a film and the state of infrared radiation. This is a method that can be measured without being affected by the difference in rate. However, there has not yet been proposed any practical one.

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. Is to provide.

[0020]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted studies as described in detail below and obtained various findings.

That is, in the present invention, calibration is performed for each substrate (for example, a silicon wafer) in order to use an infrared radiation thermometer as a main temperature measuring means. Specifically, before processing the substrate by the target vacuum processing apparatus, heating or cooling to a known temperature for each substrate in a stage in the temperature calibration chamber, at one point or at multiple temperatures, The temperature of the substrate is measured by a first infrared radiation thermometer. From the indicated value of the first infrared radiation thermometer obtained at this time, a correction is applied to the infrared radiation thermometer in the vacuum processing chamber after the temperature calibration chamber. Specifically, by knowing this correction value in advance, the calibration of the infrared radiation thermometers after the temperature calibration chamber is performed using, for example, a coarse correction or a simple coefficient if the correction is performed in a narrow temperature range. When there are a plurality of temperature calibration points, there is a method of taking in the respective temperature calibration data into a computer and performing a calculation for correction.

The temperature calibration chamber described above is not limited to a vacuum and may be in an environment of atmospheric pressure. Under atmospheric pressure environment, not only the device structure is generally simplified, but also
The temperature of the target wafer can be more easily brought close to the temperature of the heat block (stage) heated or cooled to a known temperature.

Specifically, when the temperature calibration chamber is set at atmospheric pressure, it is possible to use a vacuum chuck on the stage to bring the substrate into close contact with a heat block having a larger heat capacity than the substrate. 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 at the above-mentioned temperature calibration point, a problem such as oxidation of the surface of the target substrate occurs depending on the atmosphere. Therefore, the atmosphere in 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 in a vacuum, in order to improve the heat conduction between the heat block and the base as described above, a heating or cooling gas is heated between the two at a pressure of 5 Pascal or more. By interposing 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 a vacuum processing tank, the moisture adsorbed on the surface of the substrate is sufficiently removed. For this reason, it is necessary to heat the substrate to 150 ° C. or higher, and conversely, it is necessary to lower the temperature of the substrate already heated to a film formation start temperature of about 50 ° C. in a vacuum chamber. There are cases where there is. In the case of the temperature increase and the temperature decrease, it is necessary to accurately measure the temperature each time the temperature is controlled, and it is necessary to calibrate the infrared radiation thermometer for measuring these temperatures in advance for each substrate. That is, before performing a predetermined vacuum processing, the substrate is heated or cooled to a known temperature in advance, the temperature of the substrate is measured by a first infrared radiation thermometer, and the substrate is used in a subsequent vacuum processing process based on the measurement result. A film forming apparatus having a function of calibrating one or a plurality of second infrared radiation thermometers, and having a need to accurately control the temperature of a substrate, such as a sputtering apparatus or a CVD apparatus, is more electronically structured. A process suitable for parts can be realized.

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

Further, when the first infrared radiation thermometer at the above-mentioned known temperature is calibrated with a heated substrate, if the heating operation to the known temperature is performed in a vacuum, water adsorbed on the substrate can be removed. Can also be used as the so-called baking process, so that the scale of the apparatus can be reduced, which is sometimes preferable.

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

When heating with a lamp is used in a 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 preferred that the wavelength is within the specified wavelength range.

When a silicon wafer is used as the substrate, for example, since the silicon wafer is almost transparent in the infrared region, it cannot be efficiently heated by a generally used infrared lamp containing quartz glass. In addition, since this type of infrared lamp tends to generate stray light with respect to the infrared radiation thermometer, it is more preferable to use a short wavelength lamp having a high absorption efficiency of a silicon wafer.

If the temperature for starting film formation on the substrate in the vacuum processing chamber is lower than the baking heating temperature in vacuum for removing adsorbed moisture from the substrate, the baking is performed. Then, the substrate must be cooled to a predetermined temperature in a vacuum chamber and the substrate must be adjusted to a predetermined film formation start temperature. In order to realize such a film forming process with high accuracy, a stage having a first infrared radiation thermometer for performing temperature calibration in a temperature calibration chamber, and a stage for baking a substrate in a vacuum are provided. A stage for cooling to a temperature at which a predetermined film formation is started before further starting film formation;
Then, a sputtering apparatus having a second infrared radiation thermometer capable of accurately measuring the substrate temperature in the cooling stage by calculating and using a correction value obtained by the first infrared radiation thermometer is required.

In order to observe the substrate with an infrared radiation thermometer, it is necessary to provide an observation through-hole (opening window) on the heating or cooling stage, but this causes non-uniformity 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, an opening window for observing the substrate temperature by an infrared radiation thermometer is provided on one of the heating or cooling stages. By providing an opening window on the other temperature measurement stage, and heating or cooling the substrate on one stage, and immediately transferring the substrate to the other stage and measuring the temperature, it is possible to reduce such non-uniformity. it can.

By providing a plurality of temperature calibration points, more accurate control of the process temperature becomes possible. However, by providing a plurality of heating means or cooling means in the substrate temperature calibration chamber, calibration at a plurality of temperatures can be shortened. Can be done on time.

In the case of an apparatus for forming a metal film by sputtering, an infrared ray radiated on a surface opposite to the surface on which the metal film formed on the substrate is observed is reflected. If not, the magnitude 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 by the shutter Since the radiated infrared rays are almost reflected, the difference in apparent infrared emissivity before and after the 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 has sufficient wavelength for the measurement wavelength of the infrared radiation thermometer. By disposing a shutter mechanism whose main surface is formed by a member which is a mirror surface, stray light penetrating the base and entering the infrared radiation thermometer can be blocked.

The present invention has been made on the basis of the above findings. The means for achieving the object will be specifically described below. The object of the present invention is to control the temperature of a substrate on which a film is to be formed. A film forming method for performing a film forming process on the substrate,
Before the film forming process, a step of causing the substrate to simulate infrared radiation characteristics exhibited during and after the film forming process, and measuring the radiation intensity of the substrate at a known temperature by a first infrared radiation thermometer. From the output of the first infrared radiation thermometer, which measures the radiation intensity from the substrate in the pseudo state based on the known temperature, to correctly obtain the temperature of the substrate by the second infrared radiation thermometer Calculating the infrared sensitivity correction value of the substrate and storing it in the storage means; and during and after the film formation processing of the substrate to be measured under unknown temperature conditions, the radiation intensity of the substrate is measured by the second infrared radiation. Measuring with a thermometer, and correcting the output from the second infrared radiation thermometer for measuring the radiation intensity of the substrate based on the previously acquired infrared sensitivity correction value, thereby obtaining the true temperature of the substrate. calculate And degree, according to the temperature that the calculated,
This is achieved by a film forming method including a step of performing a film forming process by controlling the temperature of the substrate.

Preferably, before the film forming process, a step of simulating the infrared radiation characteristic exhibited by the substrate during and after the film forming process is performed on the surface on which the substrate is subjected to the film forming process. And a step of bringing a member substantially constituting a mirror surface close to the measurement wavelength of the first infrared radiation thermometer.

[0039]

Before performing predetermined processing on a substrate in a vacuum processing chamber, the substrate is heated or cooled to a known temperature in a temperature calibration chamber, and the temperature of the substrate is measured by a first infrared radiation thermometer and a thermocouple. It measures and calculates the correction value of the infrared radiation thermometer, that is, the emissivity based on the measurement result.
Based on the calculation result, the temperature of the substrate in the subsequent vacuum processing chamber 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 the vacuum processing such as the film forming processing is performed in an accurately controlled temperature state.

In the temperature calibration chamber, the first
By measuring the calibration temperature with the infrared radiation thermometer and the thermocouple at different temperatures, it is possible to control the process temperature in a wide temperature range when controlling the temperature of the substrate in the vacuum processing chamber thereafter. Will be possible.

Further, by providing a plurality of means as a heating means or a cooling means for measuring the calibration temperature by the first infrared radiation thermometer and the thermocouple described above, calibration at 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 while heating or cooling the substrate, it is necessary to provide a through-hole (opening window) in the heating or cooling stage. Non-uniformity in distribution may occur. Therefore, as a countermeasure, it is possible to heat both the front and back surfaces of the base, but it is possible to divide the stage into two stages and to provide a stage dedicated to temperature control without providing an opening window on one of the substrate heating or cooling stages. The temperature measurement stage may be provided with an opening window, and the temperature may be measured by moving the substrate from one stage to the other stage when measuring the temperature.

In the present invention, arranging 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 an apparatus for forming a metal film by sputtering or CVD, the same infrared emissivity as the metal film is formed by this shutter is used regardless of the presence or absence of the metal film. Therefore, the difference in apparent infrared emissivity before and after film formation can be corrected, and correct temperature control of the substrate can be performed based on accurate temperature measurement. Another object of the present invention is to block stray light that penetrates a substrate and enters an infrared radiation thermometer, thereby preventing a measurement error due to the stray light.

This shutter mechanism is indispensable especially for measuring the temperature of the substrate before film formation. Other operations that cannot be described here will be specifically described in the section of the embodiment.

[0045]

An embodiment of the present invention will be described below with reference to the drawings.

<Embodiment 1> FIG. 1 is a schematic structural view showing an embodiment in which the vacuum processing apparatus of the present invention is applied to a sputtering film forming apparatus. In this embodiment, an example in which a silicon wafer is used as a substrate to be formed and an Al thin film is formed thereon by sputtering will be described as a typical example.

The vacuum processing apparatus 1 of the present invention includes 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, It comprises three chambers: a stage 7, an Al target 8, and a sputter deposition chamber 4 having a sputter electrode 9. These chambers are respectively gate valves GV1 and GV
Connected and independent by V2.

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

Further, each stage is provided with heating and cooling means as described later, and an opening window 19 comprising a through-hole for observing radiant infrared rays from the base 10 is provided. The first, second and third infrared radiation thermometers 1 are optically coupled through the opening window 19.
1, 14, and 15 are connected. The substrate temperature calibration stage 5 is provided with a thermocouple 12 for accurately measuring the temperature of the substrate temperature calibration stage 5. The output from each infrared radiation thermometer and the output from 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. It corrects the thermometers 14 and 15 to measure the correct temperature of the substrate 10 on each stage, and finally issues a command to set a predetermined stage temperature based on these measurement data to heat and cool each stage. A base temperature controller 13 is provided to control the temperature of the vacuum processing apparatus as a whole by setting and controlling the temperature of the stage to a predetermined value by feeding back to the means.

The function of each chamber will be described. In the substrate temperature calibration chamber, the first infrared radiation thermometer 11 normally receives infrared radiation from the substrate 10 set at a known temperature higher than the film formation start temperature. Measure and calculate the emissivity to calibrate the infrared radiation thermometer. The substrate temperature adjustment chamber 3 has a temperature adjustment function before transferring the substrate to the next sputter deposition chamber 4, and the sputter deposition chamber 4 has a function of forming a film on the substrate by sputtering.

Hereinafter, the temperature of each stage is controlled to
A specific example in which an Al thin film is sputter-deposited on the silicon wafer substrate 10 from the Al target 8 while maintaining 0 at a predetermined temperature will be described.

First, in the substrate temperature calibration chamber 2 placed under the atmospheric pressure, the wafer 10 is heated stepwise 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 described later.

The substrate 1 heated on the calibration stage 5
0 is connected to the first infrared radiation thermometer 11 and the thermocouple 12.
Observation and measurement are performed, and the arithmetic processing unit of the substrate temperature controller 13 obtains the indicated value of the temperature at each temperature stage. That is, the thermocouple 12
, The temperature of the calibration stage parallel to the substrate temperature is actually measured, and the emissivity at that time is measured with the infrared radiation thermometer 11 using the temperature as the substrate temperature, and this radiation is calculated by the arithmetic processing unit of the substrate temperature controller 13. Obtain an indication of temperature based on the rate.

Since the temperature of the wafer 10 is previously set to a known temperature, the emissivity obtained from the first infrared radiation thermometer 11 can be calculated by back calculation. The processing temperatures of the temperature adjustment chamber 3 and the sputter deposition chamber 4 are determined by using this emissivity.
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 inside of the substrate temperature calibration chamber 2 is evacuated to a vacuum state, and then the wafer 10 is opened by opening the gate valve GV1 to open the calibration chamber. 2 is transferred to a substrate temperature adjusting chamber 3 under vacuum, and is transferred to a second infrared radiation thermometer 1.
4, the temperature is measured. From the measurement result, the temperature of the stage 6 is adjusted by the substrate temperature controller 13 and the wafer 1 is adjusted.
Adjust the temperature of 0 to any temperature. In this example, 100
Set to ° C. After that, the wafer 10 is
V2 is opened, transported to the stage 7 of the sputtering film formation chamber 4 in a vacuum state, measured by the third infrared radiation thermometer 15, and based on the result, the temperature of the stage 7 is adjusted to an arbitrary temperature. The temperature of the base 10 is controlled to an arbitrary temperature to form a sputter film. In this example, the temperature was set to 250 ° C. to form an Al sputter film. After the sputter deposition, the wafer 10 was transferred to the calibration chamber 2 again, and the emissivity was re-calibrated, and the emissivity was used for correction in the temperature measurement during the subsequent sputter deposition. As a simple means for transferring between the chambers, for example, a transfer mechanism using a heat-resistant belt such as silicone rubber is used.

Next, the outline of the structure of the stage on which the substrate is placed, the method of heating and cooling, and the method of measuring the emissivity of the wafer will be described using the example of the sputtering stage 7 with reference to FIG.

(1) Structure of substrate stage and method of heating and cooling: The sputter stage 7 has a built-in electric heater 18 for heating the stage, and transmits heat to the wafer in a vacuum, such as air or nitrogen gas. The structure has a structure in which the heat transfer gas flows, and a clamp 17 for uniformly bringing the heat transfer gas into contact with the wafer is provided. Further, there is provided an opening window 19 constituting a radiation observation cavity for measuring the temperature of the wafer with the infrared radiation thermometer 15. When cooling the wafer, although not shown, a stage is cooled by circulating a cooling medium such as freon instead of the heater 18,
The wafer is cooled by the heat transfer gas as described above.

In the calibration stage 5, since the inside of the chamber is at atmospheric pressure, vacuum evacuation is performed without using heat transfer gas, and heat transfer is performed by heat conduction while maintaining close contact with the stage by means of a vacuum chuck. .

(2) Measurement of emissivity: Next, a method of measuring the temperature of the wafer base using an infrared radiation thermometer will be described.
In the present embodiment, the infrared radiation thermometers 11, 14, and 15 are installed below each stage to set the temperature on the back side of the wafer, and stray light from 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 processing in a vacuum is a film formation of Al on a substrate by sputtering. When the substrate receives the Al metal film, the emissivity is greatly increased by the amount reflected from the Al film. Therefore, the emissivity obtained by measuring the film forming process in the substrate temperature calibration chamber cannot be used in the subsequent film forming process.

In the present invention, the wafer on which the film forming process has been completed is heated again to a preset known temperature in the calibration chamber, the emissivity is measured again on a new surface, and recalibration is performed. Thus, for example, the wafer temperature immediately after the film formation can be correctly measured by measuring the wafer immediately after the film formation by an infrared radiation thermometer and calculating the correct emissivity by the (second) emissivity measurement after the film formation. It is possible to know.

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

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

In the above embodiment, an example was described in which a silicon wafer was used as a substrate and an Al thin film was formed on the back surface by sputtering. However, since the temperature of the substrate could be controlled with high precision via a stage, reproducibility within the wafer was obtained. However, good crystallinity was obtained, and high-quality film formation was achieved.

<Example 2> When a metal film is formed on the opposite side of the substrate 10 observed by an infrared radiation thermometer, the value of the apparent infrared emissivity 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 sputter film formation chamber 4 of FIG. 1 to calibrate the infrared emissivity of the substrate after film formation in the sputtering apparatus for such a purpose. It is shown.

During the film formation by sputtering, the temperature of the substrate is measured by the infrared radiation thermometer 15. However, in this case, since the metal film has already been formed on the surface of the base 10, the correction value of the infrared emissivity obtained in the base temperature calibration stage 2 cannot be used. For this purpose, after the sputter deposition, the substrate 10 is transferred from the sputter deposition chamber 4 to the second temperature calibration chamber 32, and heated or cooled to a predetermined temperature by the heating or cooling stage 33 similarly to the temperature calibration chamber 2, Infrared radiation thermometer 3
The temperature is measured by the thermocouple 4 and the thermocouple 35, 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 the film formation with this value, the temperature of the substrate during the film formation can be accurately obtained. If the temperature of the substrate 10 during the 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 in order to appropriately adjust the temperature of the substrate. By applying the feedback, it is possible to appropriately perform a film forming process on the next substrate.

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. There is no need to prepare them separately. That is, after forming a film in the sputtering film forming chamber 4, the substrate is again transferred to the temperature calibration chamber 2 through the substrate temperature adjusting chamber 3.
Then, the infrared ray emissivity may be calibrated in the same manner as in the second temperature calibration chamber 32.

<Embodiment 3> In Embodiments 1 and 2 described above, the emissivity of the substrate changes when the substrate is formed into a film, so that the emissivity needs to be re-calibrated again. This point is improved, and the correction of the infrared radiation thermometer can be performed by using the emissivity as a reference in the subsequent film forming process by one-time emissivity calibration.

This embodiment also describes an apparatus example in which aluminum Al is formed on a silicon wafer substrate by sputtering, as in the first embodiment.

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

The substrate 10 is first heated or cooled to a predetermined temperature by the heating or cooling stage 5 in the temperature calibration chamber 2, and the temperature is measured by the first infrared radiation thermometer 11 and the thermocouple 12, and the indicated values of both are measured. The infrared emissivity of the substrate 10 at a predetermined temperature is calculated from the following equation. 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 value of the infrared emissivity may vary 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 measurement by the infrared radiation thermometer 11 is performed 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 heating or cooling on the heating or cooling stage 6. By adjusting the temperature of the heating or cooling stage 6 to a predetermined temperature through the substrate temperature controller 13 by correcting the emissivity of the substrate 10 at the predetermined temperature obtained in the calibration chamber 2, the temperature of the substrate 10 is controlled to a predetermined temperature. Control the temperature. The measurement is also performed on the thermometer side of the substrate temperature adjustment chamber 3 with the shutter 21 closed as in the case of the temperature calibration chamber 2.

After that, the substrate 10 is
And heated or cooled by the sputter stage 7. At this time, the shutter 22 is closed on the base, the temperature of the base 10 is measured by the third infrared radiation thermometer 15, and the correct temperature is known by correcting the emissivity of the base 10 obtained in the calibration chamber 2. Can be. Further, by knowing the correct temperature in this way, the substrate temperature controller 1
The temperature of the heating or cooling stage 7 is adjusted to a predetermined temperature through 3 and the temperature of the base 10 is controlled to a predetermined temperature to start sputtering film formation. After the film formation is completed, the substrate 10 is returned to the substrate temperature adjustment 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, the temperature of the stage 6 is adjusted to a predetermined temperature through the substrate temperature controller 13 by correcting the emissivity of the substrate at the predetermined temperature obtained in the calibration chamber 2 to set the substrate temperature to the predetermined value. I do. Thereafter, 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 at a plurality of temperatures by the first infrared thermometer 11 and the thermocouple 12 in the substrate temperature calibration stage 2, and the second and third infrared radiation thermometers 14 and 15 are measured. Use allows for more accurate control of the process temperature. Although not shown, by providing a plurality of means for heating or cooling the substrate for measurement with the first infrared radiation thermometer 11 for substrate temperature calibration, the temperature of the substrate at a plurality of similar temperatures can be reduced. 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 configuration of the stage is basically the same as the example in FIG. 2, except that a shutter 22 is provided near the upper part of the base 10 in the present embodiment.

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 since 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, the measurement by the infrared thermometer for temperature calibration does not need to be performed twice before and after the film formation by arranging the second temperature calibration chamber 32 or the like, so that only one measurement is required.

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

Further, since the silicon wafer substrate 10 is almost transparent to infrared rays, stray light penetrates the substrate and enters the infrared radiation thermometer, which may lower the temperature measurement accuracy of the substrate. As a countermeasure, in this example, a shutter 22 whose main surface is formed by a member which is close to the base on the side opposite to the side observed by the infrared thermometer and which is sufficiently specular with respect to the measurement wavelength of the infrared radiation thermometer. During the temperature measurement of the base 10 by the infrared radiation thermometer 15, the stray light is blocked so as not to enter.

As described above, the role of the shutter mechanism is to firstly correct the increase in the apparent emissivity due to the radiation light from the wafer reflected by the metal film when the metal film is formed on the wafer substrate. The second is to block stray light.

FIG. 6 is a schematic configuration diagram of the stage 6 in FIG. 4, and has basically the same configuration as the stage 7 in FIG. The stage 6 has a built-in heater 18 and has a structure in which a heat transfer gas flows in a space between the stage 6 and the base 10 in a vacuum, and a clamp 17 for bringing the heat transfer gas into uniform contact with the base. is set up. Base 1
An opening window 19 for measuring a temperature of 0 with an infrared radiation thermometer 14 and a stray light blocking cylinder 16 are connected.
Window plates 23 and 24 made of a material that transmits infrared rays are attached to both ends of 6. Further, the cylinder 16 is heated and cooled by water so as not to become a source of stray light. In order to further reduce the influence of the stray light, the inner wall of the cylinder 16 can be subjected to black body processing. Also, in this example, the shutter 21 is located close to the base 10 as in FIG.
Are arranged.

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

FIG. 7 is a characteristic curve showing the difference in the infrared emissivity of the silicon wafer base with and without the shutter.
FIG. 7A is a comparative example without a shutter, and FIG.
4 shows the measurement results of the present example in which a shutter was provided. As apparent from this, the apparent infrared emissivity of the wafer before the aluminum Al film formation (without the Al film) in FIG.
Although the apparent infrared emissivity of the wafer after film formation (with an Al film) is smaller than the apparent infrared emissivity of the wafer, by installing a shutter on the wafer before the Al film formation, FIG.
As shown in (b), the apparent infrared emissivity was almost equal to that of the wafer after the Al film formation. Thus, it can be seen that by measuring the substrate temperature using the shutter, measurement can be performed at a constant emissivity.

<Embodiment 4> If the temperature distribution of the substrate becomes uneven 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) as shown in FIG. After the base 10 is heated or cooled by a stage 25 dedicated to heating or cooling separately provided at a location remote from the base 19, the base 10 is transported to a stage having an opening window 19, and the temperature is measured by an infrared radiation thermometer 27. The measurement can be performed in a state where the temperature distribution of the base 10 is more uniform.

Embodiment 5 When heating or cooling of the substrate is performed only from one of the front surface and the rear surface, a temperature difference occurs between the front surface and the rear surface of the substrate. Therefore, as shown in FIG. 9, the heating or cooling means 28, 2
The provision of 9 makes it possible to reduce the temperature difference between the two surfaces. This can also reduce the non-uniformity of the temperature distribution on the substrate due to the opening window 19.

<Embodiment 6> Another embodiment in which an aluminum Al film is formed on a silicon wafer substrate 10 by sputtering using the sputtering apparatus 1 of 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, measured by the thermocouple 12 and calibrated for the emissivity of the infrared radiation thermometer 11 based on the temperature. Then, the wafer is transferred to the substrate temperature adjusting chamber 3. The wafer substrate 10 transported to the substrate temperature adjustment chamber 3 is measured by an infrared radiation thermometer 14, cooled to a predetermined 200 ° C. by controlling the temperature of the stage 6, and transported to the sputter deposition chamber 4. The substrate 10 is sputtered in the sputtering film forming chamber 4 according to a temperature profile as shown in FIG. Target 8 is 1% Si-3% Cu-
An Al composition was used. First, the temperature of the substrate 10 is controlled to 230 ° C., and the first
And then temporarily stop the sputtering,
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 controlled to be heated to 300 ° C. to grow the crystal grains of the Al film obtained by the first sputter deposition to improve the orientation and the like. Next, the substrate is transported again to the sputtering film forming chamber 4, and after setting the substrate temperature to about 400 ° C., the second sputtering film formation is restarted and the film is formed to 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, the substrate is immediately transferred to the substrate temperature adjusting chamber 3 and rapidly cooled to about 50 ° C. Thereby, the deposition of Si and Cu in the Al sputtered film could be suppressed.

In the above embodiment, an example was described in which a silicon wafer was used as a base and an Al thin film was formed on the surface by sputtering. However, since the temperature of the base could be controlled with high precision via a stage, the reproducibility in the wafer was high. However, good crystallinity was obtained, and a film having excellent quality could be achieved. For example, when heating a thin film having a thickness of several hundred degrees 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, which can know an accurate temperature.

The vacuum processing apparatus according to the present invention is not limited to the above-described sputtering apparatus, and may be a CVD (Chemicai Vapor Depositi).
It is needless to say that the present invention can be applied to a film forming apparatus according to on).

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

In any of the film forming apparatuses of this type, the precision of controlling the temperature of the substrate affects the quality of the film to be formed. Therefore, the film forming apparatus of the present invention can sufficiently respond to such a problem.

Note that a film forming apparatus can be realized by using a vacuum processing chamber as a film forming processing chamber as in the above embodiment. However, this vacuum processing chamber can be replaced by a dry etching process such as plasma etching. 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.
In addition, since the temperature during film formation can be easily controlled, a high-quality film can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a partial cross-section of a vacuum processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional configuration diagram illustrating an example of a sputtering stage.

FIG. 3 is a block diagram schematically showing a partial cross section of a vacuum processing apparatus according to another embodiment of the present invention.

FIG. 4 is a partial cross-sectional block diagram schematically illustrating a vacuum processing apparatus according to 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 adjustment 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 adjustment stage each provided with a shutter mechanism.

FIG. 7 is a characteristic curve diagram showing temperature measurement results depending on the presence or absence of 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 sectional view of a stage in which temperature control means are 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.

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[Procedure amendment]

[Submission date] December 15, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Deposition method

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a film deposition method using the vacuum processing apparatus for performing various processes on the substrate in a vacuum, particularly suitable vacuum processing apparatus used in the manufacturing process of the semiconductor device <br />.

[0002]

2. Description of the Related Art In a process apparatus used for manufacturing a semiconductor device, it is important to accurately control a process temperature in order to realize a well-controlled reaction or the like. A representative example of a process apparatus in which the temperature is the most important setting condition is a so-called furnace such as an oxidation furnace. The inside of this kind of furnace is an oxidizing atmosphere replaced with the atmosphere. In this case, the replacement atmosphere is at or above atmospheric pressure, and for example, a silicon wafer in the furnace body is heated by radiation from a heater installed around a quartz tube and heat conduction by the atmospheric pressure atmosphere in the quartz tube. . That is, since there is a medium for conducting heat, the temperature can be measured relatively accurately using a measuring element such as a thermocouple installed in the heat conducting atmosphere.

Further, as an example in which a heat conductive medium is not used, a photoresist baking apparatus used in a step of applying a photoresist used as a mask in an etching step can be exemplified. 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. The entire surface of the silicon wafer is pressed against the heat block by atmospheric pressure using a vacuum chuck. Therefore, 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 rely on highly pure materials and well-controlled reactions in a dust-free environment, often requiring processing in a 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, the medium is not heated, and the wafer is heated only by the radiation. Therefore, as is well known, only a small absorption occurs on the metal mirror surface, and a large absorption occurs on the black body. Occurs, and as a result, the degree of heating greatly differs depending on the surface state of the wafer to be heated.

Attempts have been made to accurately measure the temperature of the wafer during the process by attaching a thermocouple to the wafer. However, in order to measure the temperature of the wafer while the thermocouple is in point contact with the wafer, the temperature of the thermocouple is measured. It is difficult to stabilize the contact state to a constant level, and the measurement temperature has a drawback of poor reproducibility.

When a wafer is heated by infrared radiation, the wafer is almost transparent in a wide range of the infrared region, so that heat is not transmitted to the thermocouple only by conduction from the wafer, but the thermocouple itself is heated. In some cases, the wafer may be heated by a lamp heater, and it is difficult to accurately measure the temperature of the wafer.

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 set in a vacuum atmosphere, and the back surface of the silicon wafer is connected to the heat block. By filling the gas with a pressure of about 1 Torr in between, the temperature of the wafer is equilibrated with the temperature of the heat block. Also in this case, the temperature of the wafer can be controlled and managed 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 with a small force as compared with the use of a vacuum chuck under atmospheric pressure, the uniformity and reproducibility of the temperature are not sufficient. The biggest disadvantage is that the heat transfer medium 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, the temperature of the wafer must be measured in a non-contact manner in a vacuum. As one of the methods, there has been proposed a method of measuring a radiation intensity from a wafer in an infrared region using an infrared thermometer.

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

[0012] Japanese Patent Application Laid-Open No. 1-129966 can be cited as one related to this kind of technology.

[0013]

However, in this method, since the emissivity of the wafer is not always constant as described below, it is difficult to accurately measure the temperature, and there are some problems. That is, the same metal as the target material is used for the calibration sample,
For example, a silicon wafer formed by depositing aluminum of several hundred degrees is used, but the infrared emissivity from the wafer surface varies depending on the presence or absence of a metal film on the surface of the wafer to be observed by an infrared thermometer. Can not do. When a metal film is formed, a mirror surface is formed.
The emissivity is very low, making measurement difficult.
In some cases.

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

In order to accurately measure the temperature of a wafer in a vacuum and to control the temperature associated therewith, even if a wafer on which the same metal film is formed has a difference in infrared emissivity depending on the product lot, calibration is performed as in this example. In a method in which a separate wafer is prepared, accurate temperature control cannot be performed because the wafer is not a wafer on which a film is actually formed.

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

In other words, an ideal method of controlling the temperature of a wafer using an infrared thermometer is to calibrate the infrared thermometer using the wafer itself on which a film is actually formed, and to detect infrared radiation based on the presence or absence of the film and its state. This is a method that can be measured without being affected by the difference in rate. However, there has not yet been proposed any practical one.

Accordingly, 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. Is to provide.

[0019]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted studies as described in detail below and obtained various findings.

That is, in the present invention, calibration is performed for each substrate (for example, a silicon wafer) in order to use an infrared radiation thermometer as a main temperature measuring means. Specifically, before processing the substrate by the target vacuum processing apparatus,
Then , heating or cooling to a known temperature is performed, and the temperature of the base is measured at a temperature of one or more points by a 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 stage . Specifically, knowing this correction value in advance, for example, coarse correction,
Alternatively, if the target is a narrow temperature range, the calibration of the infrared radiation thermometer after the temperature calibration stage is performed using a simple coefficient. When there are a plurality of temperature calibration points, there is a method of taking in the respective temperature calibration data into a computer and performing a calculation for correction.

The above-mentioned temperature calibration stage is not limited to a vacuum and may be in an environment of atmospheric pressure. Under atmospheric pressure environment, not only the device structure is generally simplified, but also
The temperature of the target wafer can be more easily brought close to the temperature of the heat block (stage) heated or cooled to a known temperature.

Specifically, when the temperature calibration stage is set at atmospheric pressure, it is possible to use a vacuum chuck for 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. Temperature calibration section
Need not be provided close to the so-called sputtering device body.
And it is not necessary to incorporate it into the main body of the sputtering apparatus.

[0023] When the need to take high temperature of the calibration point as described above, depending on the atmosphere than problems such as the surface of the substrate of interest is oxidized occurs, temperature calibration stearate
It is more preferable that the atmosphere of the chamber having the gaseous atmosphere be an atmosphere replacing the atmosphere, for example, a nitrogen or argon atmosphere.

When the temperature calibration stage is set in a vacuum, in order to improve the heat conduction between the heat block and the substrate as described above, a heating or cooling gas is applied between the two at a pressure of 5 Pascal or more. By interposing 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 sputtering, when the substrate in the atmosphere is taken into a vacuum processing tank, moisture adsorbed on the surface of the substrate is sufficiently removed. For this reason, it is necessary to heat the substrate to 150 ° C. or higher, and conversely, it is necessary to lower the temperature of the already heated substrate in the vacuum chamber to the film formation start temperature. is there. In the case of temperature rise and temperature decrease, accurate temperature measurement is required every time temperature control is performed.
It is necessary to calibrate the infrared radiation thermometer for measuring these temperatures in advance for each substrate. That is heated to a substrate in advance to a known temperature before performing the predetermined vacuum processing was cooled, such as by measuring the substrate temperature by the first infrared radiation thermometer, vacuum the subsequent process based on the measurement result A function capable of calibrating one or more second infrared radiation thermometers used in the process,
If a film forming apparatus, such as a sputtering apparatus or a CVD apparatus, that needs to accurately control the temperature of the substrate is configured, a process more suitable for electronic components can be realized.

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

When the first infrared radiation thermometer at the known temperature is calibrated with a heated substrate, if the heating to a known temperature is performed in a vacuum, water adsorbed on the substrate can be removed. Can also be used as the so-called baking process, so that the scale of the apparatus can be reduced, which is sometimes preferable.

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

When heating with a lamp is used in a 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 preferred that the wavelength is within the specified wavelength range.

When a silicon wafer is used as the substrate, for example, the silicon wafer is almost transparent in the infrared region, so that the infrared lamp containing quartz glass, which is widely used, cannot perform highly efficient heating. As a lamp
It is more preferable to use a silicon wafer having a short wavelength having a high absorption efficiency.

If the temperature for starting film formation on the substrate in the vacuum processing chamber is lower than the baking heating temperature in vacuum for removing adsorbed moisture from the substrate, the baking is performed. Then, the substrate must be cooled to a predetermined temperature in a vacuum chamber and the substrate must be adjusted to a predetermined film formation start temperature. In order to realize such a film forming process with high accuracy, a stage provided with a first infrared radiation thermometer for performing temperature calibration of a second radiation thermometer in a temperature calibration chamber, and a stage provided in a vacuum. A stage for baking the substrate,
Further, a stage for cooling to a temperature at which a predetermined film formation is started before the film formation is started, and a substrate temperature at the cooling stage is accurately calculated and calculated by using a correction value obtained by a first infrared radiation thermometer. A sputtering apparatus having a second infrared radiation thermometer capable of measuring the temperature is required.

When observing the substrate with an infrared radiation thermometer ,
Observation of the metal film surface shows that the emissivity is small as described above.
Measurement is difficult, so the surface opposite to the surface on which the metal film is
It is desirable to observe. For this purpose, it is necessary to provide a through hole (opening window) for observation on the heating or cooling stage, but this may cause non-uniformity in the temperature distribution of the substrate. In this case, the stage is divided into two in the same chamber, and both are adjusted to have the same temperature. That is, an opening window for observing the substrate temperature by an infrared radiation thermometer is provided on one of the heating or cooling stages. By providing an opening window on the other temperature measurement stage, and heating or cooling the substrate on one stage, and immediately transferring the substrate to the other stage and measuring the temperature, it is possible to reduce such non-uniformity. it can.

By providing a plurality of temperature calibration points, more accurate control of the process temperature becomes possible, 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 shortened. Can be done on time.

Further, in the case of the apparatus for forming a metal film by sputtering, for reflecting infrared radiation radiated in the opposite surface to the surface on which the metal film formed on the substrate is observed, the film
The presence or absence of different size of the radiation incident on the infrared radiation thermometer, but the apparent infrared emissivity is different, the following
Since the shutter described above almost reflects infrared rays radiated to the surface of the substrate opposite to the surface observed by the infrared radiation thermometer, the difference in apparent infrared emissivity before and after film formation can be significantly reduced. .

In the stage for heating or cooling the substrate, the substrate is brought into close proximity to the surface opposite to the surface observed by the infrared radiation thermometer through the opening window of the stage and has a sufficient wavelength for the measurement wavelength of the infrared radiation thermometer. By disposing a shutter mechanism whose main surface is formed by a member which is a mirror surface, stray light penetrating the base and entering the infrared radiation thermometer can be blocked.

The present invention has been made on the basis of the above findings. The means for achieving the object will be specifically described below. The object of the present invention is to control the temperature of a substrate on which a film is to be formed. A film forming method for performing a film forming process on the substrate,
Before the film forming process, a step of causing the substrate to simulate infrared radiation characteristics exhibited during and after the film forming process, and measuring the radiation intensity of the substrate at a known temperature by a first infrared radiation thermometer. From the output of the first infrared radiation thermometer, which measures the radiation intensity from the substrate in the pseudo state based on the known temperature, to correctly obtain the temperature of the substrate by the second infrared radiation thermometer Calculating the infrared sensitivity correction value of the substrate and storing it in the storage means; and during and after the film formation processing of the substrate to be measured under unknown temperature conditions, the radiation intensity of the substrate is measured by the second infrared radiation. Measuring with a thermometer, and correcting the output from the second infrared radiation thermometer for measuring the radiation intensity of the substrate based on the previously acquired infrared sensitivity correction value, thereby obtaining the true temperature of the substrate. calculate And degree, according to the temperature that the calculated,
This is achieved by a film forming method including a step of performing a film forming process by controlling the temperature of the substrate.

Preferably, before the film forming process, a step of simulating the infrared radiation characteristic exhibited by the substrate during and after the film forming process is performed on the surface on which the substrate is subjected to the film forming process. And a step of bringing a member substantially constituting a mirror surface close to the measurement wavelength of the first infrared radiation thermometer.

Further , the above object is to provide a substrate having a known state quantity.
In a state where the substrate has been subjected to a desired treatment.
Simulate the physical properties of the object at the time
Obtain the physical quantity obtained by measuring the physical quantity,
This is stored in the storage means, and the process in which the substrate has an unknown state
During the measurement of the physical quantity of the substrate, the measured value obtained from the substrate
Is supplemented based on the physical properties of the pseudo substrate obtained in advance.
Correct, calculate the true state quantity, and perform the desired processing.
Depending on the substrate processing method,
Is also achieved.

[0039]

[Action] Before performing predetermined processing on a substrate in a vacuum processing chamber, in the temperature calibration stage, the first infrared radiation thermometer is heated or cooled substrate to a known temperature c
Measure the radiation intensity from the wafer and use a thermocouple to measure the temperature of the substrate.
The stage temperature equilibrated with the temperature is measured, and the correction value of the infrared radiation thermometer or the emissivity is calculated based on the measurement result. Based on the calculation result, the temperature of the substrate in the subsequent vacuum processing chamber 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 the vacuum processing such as the film forming processing is performed in an accurately controlled temperature state.

In the temperature calibration stage , the first
By measuring the calibration temperature with the infrared radiation thermometer and the thermocouple at different temperatures, it is possible to control the process temperature in a wide temperature range when controlling the temperature of the substrate in the vacuum processing chamber thereafter. Will be possible.

Further, by providing a plurality of means as a heating means or a cooling means for measuring the calibration temperature by the first infrared radiation thermometer and the thermocouple described above, calibration at 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 while heating or cooling the substrate, it is necessary to provide a through-hole (opening window) in the heating or cooling stage. Non-uniformity in distribution may occur. So as the countermeasure, it is also possible so as to heat the substrate both sides, using two stages, the one substrate heating or cooling stage to a temperature control dedicated stage without providing the opening window, the other The temperature measurement stage may be provided with an opening window, and the temperature may be measured by moving the substrate from one stage to the other stage when measuring the temperature.

In the present invention, arranging 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 an apparatus for forming a metal film by sputtering or CVD, the same infrared emissivity as the metal film is formed by this shutter is used regardless of the presence or absence of the metal film. it is possible to obtain the difference in infrared radiation rate of apparent before and after formation of the can and corrected child lies to permit correct temperature control of the substrate based on the accurate temperature measurement, the second role , Thereby improving the intensity of infrared radiation
Therefore, it is to improve the measurement accuracy, and thirdly, stray light penetrating the base and entering the infrared radiation thermometer is blocked,
It is to prevent a measurement error due to stray light. Other operations that cannot be described here will be specifically described in the section of the embodiment.

[0044]

An embodiment of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a schematic structural view showing an embodiment in which the vacuum processing apparatus of the present invention is applied to a sputtering film forming apparatus.
In this embodiment, an example in which a silicon wafer is used as a substrate to be formed and an Al thin film is formed thereon 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, It comprises three chambers: a stage 7, an Al target 8, and a sputter deposition chamber 4 having a sputter electrode 9. These chambers are respectively gate valves GV1 and GV
Connected and independent by V2.

An exhaust system is connected to the substrate temperature calibration chamber 2 and the sputter film formation chamber 4. One side can maintain a predetermined vacuum state, and the other side allows a predetermined gas to be introduced from a gas introduction port. In the temperature calibration chamber 2, air or nitrogen gas can be introduced and set to atmospheric pressure.
The sputter deposition chamber 4 is configured so that an environment in which plasma is generated by a predetermined discharge by introducing a sputter gas can be set.

Further, each stage is provided with a heating and cooling means as described later, and an opening window 19 comprising a through-hole for observing radiant infrared rays from the base 10 is provided. The first, second and third infrared radiation thermometers 1 are optically coupled through the opening window 19.
1, 14, and 15 are connected. The substrate temperature calibration stage 5 is provided with a thermocouple 12 for accurately measuring the temperature of the substrate temperature calibration stage 5. And the first
Of the infrared radiation thermometer 11 and the output of the thermocouple 12 to calculate an infrared sensitivity correction value (emissivity) , and based on the calculation result, the second and third infrared radiation 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 fed back to the heating and cooling means of each stage. The substrate temperature controller 13 for setting and controlling the temperature of the stage to a predetermined value and for controlling the temperature of the so-called vacuum processing apparatus as a whole is provided.

The function of each chamber will be described. The substrate temperature calibration chamber normally measures the infrared radiation intensity from the substrate 10 set to a known temperature higher than the film formation start temperature by the first infrared radiation thermometer 11. And the emissivity is calculated to calibrate the infrared radiation thermometer. The substrate temperature adjustment chamber 3 has a temperature adjustment function before transferring the substrate to the next sputter deposition chamber 4, and the sputter deposition chamber 4 has a function of forming a film on the substrate by sputtering.

Hereinafter, the temperature of each stage is controlled to
A specific example in which an Al thin film is sputter-deposited on the silicon wafer substrate 10 from the Al target 8 while maintaining 0 at a predetermined temperature will be described.

First, in the substrate temperature calibration chamber 2 under the atmospheric pressure, the wafer 10 is heated stepwise 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 described later.

The substrate 1 heated on the calibration stage 5
0 is connected to the first infrared radiation thermometer 11 and the thermocouple 12.
Observation and measurement are performed, and the arithmetic processing unit of the substrate temperature controller 13 obtains the indicated value of the temperature at each temperature stage. That is, the thermocouple 12
In actually measuring the temperature of the calibration stage which is the substrate temperature and the equilibrium, the emissivity at that time was observed by infrared radiation thermometer 11 and the temperature as the substrate temperature, the arithmetic processing unit of the substrate temperature controller 13 Obtain an indication of temperature based on emissivity.

Since the temperature of the wafer 10 is set in advance to a known temperature, the emissivity obtained from the first infrared radiation thermometer 11 can be calculated by back calculation. The processing temperatures of the temperature adjustment chamber 3 and the sputter deposition chamber 4 are determined by using this emissivity.
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 inside of the substrate temperature calibration chamber 2 is evacuated to a vacuum state, and then the wafer 10 is opened by opening the gate valve GV1 to open the calibration chamber. 2 is transferred to a substrate temperature adjusting chamber 3 under vacuum, and is transferred to a second infrared radiation thermometer 1.
4, the temperature is measured. From the measurement result, the temperature of the stage 6 is adjusted by the substrate temperature controller 13 and the wafer 1 is adjusted.
Adjust the temperature of 0 to any temperature. In this example, 100
Set to ° C. After that, the wafer 10 is
V2 is opened, transported to the stage 7 of the sputtering film formation chamber 4 in a vacuum state, measured by the third infrared radiation thermometer 15, and based on the result, the temperature of the stage 7 is adjusted to an arbitrary temperature. The temperature of the base 10 is controlled to an arbitrary temperature to form a sputter film. In this example, the temperature was set to 250 ° C. to form an Al sputter film. After the sputter deposition, the wafer 10 was transferred to the calibration chamber 2 again, and the emissivity was re-calibrated, and the emissivity was used for correction in the temperature measurement during the subsequent sputter deposition. As a simple means for transferring between the chambers, for example, a transfer mechanism using a heat-resistant belt such as silicone rubber , a robot, or the like is used.

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

(1) Structure of substrate stage and method of heating and cooling: The sputter stage 7 incorporates an electric heater 18 for heating the stage, and transfers heat to the wafer in a vacuum, for example, air or nitrogen gas. The structure has a structure in which the heat transfer gas flows, and a clamp 17 for uniformly bringing the heat transfer gas into contact with the wafer is provided. Further, there is provided an opening window 19 constituting a radiation observation cavity for measuring the temperature of the wafer with the infrared radiation thermometer 15. When cooling the wafer, although not shown, a stage is cooled by circulating a cooling medium such as freon instead of the heater 18,
The wafer is cooled by the heat transfer gas as described above.

In the calibration stage 5, since the inside of the chamber is at atmospheric pressure, vacuum evacuation is performed without using a heat transfer gas, and heat transfer is performed by heat conduction while maintaining close contact with the stage by a vacuum chuck. .

(2) Measurement of emissivity: Next, a method of measuring the temperature of the wafer base using an infrared radiation thermometer will be described.
In the present embodiment, the infrared radiation thermometers 11, 14, and 15 are installed below each stage to set the temperature on the back side of the wafer, and stray light from 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 a vacuum is the formation of Al on a substrate by sputtering. When the substrate receives the Al metal film, the emissivity is greatly increased by the amount reflected from the Al film. Therefore, the substrate temperature calibration stay
The emissivity obtained by measuring the film forming process in the above becomes unusable by the subsequent film forming process.

In the present invention, the wafer on which the film forming process has been completed is heated again to a preset known temperature in the calibration chamber, the emissivity is measured again on a new surface, and the calibration is performed again. Thus, for example, the wafer temperature immediately after the film formation can be correctly measured by measuring the wafer immediately after the film formation by an infrared radiation thermometer and calculating the correct emissivity by the (second) emissivity measurement after the film formation. It is possible to know.

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

If it is desired to lower the temperature immediately after the end of the film formation without changing the set temperature at the start of the 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 of substrate cooling during film formation can be changed during film formation.

In the above embodiment, an example was described in which a silicon wafer was used as a substrate and an Al thin film was formed on the back surface by sputtering. However, since the temperature of the substrate could be controlled with high precision via a stage, the reproducibility within the wafer was However, good crystallinity was obtained, and high-quality film formation was achieved.

<Example 2> When a metal film is formed on the opposite side of the substrate 10 observed by an infrared radiation thermometer, the value of the apparent infrared emissivity 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 sputter film formation chamber 4 of FIG. 1 to calibrate the infrared emissivity of the substrate after film formation in the sputtering apparatus for such a purpose. It is shown.

During the film formation by sputtering, the temperature of the substrate is measured by the infrared radiation thermometer 15. However, in this case, since the metal film has already been formed on the surface of the base 10, the correction value of the infrared emissivity obtained in the base temperature calibration stage 2 cannot be used. For this purpose, after the sputter deposition, the substrate 10 is transferred from the sputter deposition chamber 4 to the second temperature calibration chamber 32, and heated or cooled to a predetermined temperature by the heating or cooling stage 33 similarly to the temperature calibration chamber 2, Infrared radiation thermometer 3
The temperature is measured by the thermocouple 4 and the thermocouple 35, 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 the film formation with this value, the temperature of the substrate during the film formation can be accurately obtained. If the temperature of the substrate 10 during the 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 in order to appropriately adjust the temperature of the substrate. By applying the feedback, it is possible to appropriately perform a film forming process on the next substrate.

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. There is no need to prepare them separately. That is, after forming a film in the sputtering film forming chamber 4, the substrate is again transferred to the temperature calibration chamber 2 through the substrate temperature adjusting chamber 3.
Then, the infrared ray emissivity may be calibrated in the same manner as in the second temperature calibration chamber 32.

<Embodiment 3> In Embodiments 1 and 2 described above, the emissivity of the substrate changes when the substrate is formed into a film, so that the emissivity must be recalibrated again. This point is improved, and the correction of the infrared radiation thermometer can be performed by using the emissivity as a reference in the subsequent film forming process by one-time emissivity calibration. This embodiment also describes an apparatus example for forming a film of aluminum Al on a silicon wafer substrate by sputtering, as in the first embodiment.

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

The substrate 10 is first heated or cooled to a predetermined temperature by the heating or cooling stage 5 in the temperature calibration chamber 2, and the temperature is measured by the first infrared radiation thermometer 11 and the thermocouple 12, and the indicated values of both are measured. The infrared emissivity of the substrate 10 at a predetermined temperature is calculated from the following equation. 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 value of the infrared emissivity may vary 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. Note that the measurement by the infrared radiation thermometer 11 is performed with the shutter 20 closed.

Next, the substrate 10 is transported from the temperature calibration chamber 2 to the substrate temperature adjustment chamber 3, and the temperature of the substrate 10 is measured by the second infrared radiation thermometer 14 while heating or cooling on the heating or cooling stage 6. By adjusting the temperature of the heating or cooling stage 6 to a predetermined temperature through the substrate temperature controller 13 by correcting the emissivity of the substrate 10 at the predetermined temperature obtained in the calibration chamber 2, the temperature of the substrate 10 is controlled to a predetermined temperature. Control the temperature. The measurement is also performed on the thermometer side of the substrate temperature adjustment chamber 3 with the shutter 21 closed as in the case of the temperature calibration chamber 2.

After that, the substrate 10 is
And heated or cooled by the sputter stage 7. At this time, the shutter 22 is closed on the base, the temperature of the base 10 is measured by the third infrared radiation thermometer 15, and the correct temperature is known by correcting the emissivity of the base 10 obtained in the calibration chamber 2. Can be. Further, by knowing the correct temperature in this way, the substrate temperature controller 1
The temperature of the heating or cooling stage 7 is adjusted to a predetermined temperature through 3 and the temperature of the base 10 is controlled to a predetermined temperature to start sputtering film formation. Once the metal film is formed,
The thermometer can be used without using the heater 22.

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, the substrate temperature controller 1 is corrected by correcting the substrate emissivity at a predetermined temperature obtained in the calibration chamber 2.
The temperature of the stage 6 is adjusted to a predetermined temperature through 3 to set the substrate temperature to a predetermined value. Thereafter, 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 at a plurality of temperatures by the first infrared thermometer 11 and the thermocouple 12 in the substrate temperature calibration stage 2, and the second and third infrared radiation thermometers 14 and 15 are measured. Use allows for more accurate control of the process temperature. Although not shown, by providing a plurality of means for heating or cooling the substrate for measurement with the first infrared radiation thermometer 11 for substrate temperature calibration, the temperature of the substrate at a plurality of similar temperatures can be reduced. Calibration can be performed in a shorter time. Above is the temperature calibration incorporated in the sputtering equipment
Although it is described in the form of a hand, it is prepared completely separately as described above
It is also possible.

FIG. 5 shows a schematic configuration diagram of the sputtering stage 7 of FIG. 4 as a typical example of the stage. The configuration of the stage is basically the same as the example in FIG. 2, except that a shutter 22 is provided near the upper part of the base 10 in the present embodiment.

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 since 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, the measurement by the infrared thermometer for temperature calibration does not need to be performed twice before and after the film formation by arranging the second temperature calibration chamber 32 or the like, so that only one measurement is required.

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

Further, since the silicon wafer substrate 10 is almost transparent to infrared rays, stray light penetrates the substrate and enters the infrared radiation thermometer, which may lower the accuracy of measuring the temperature of the substrate. As a countermeasure, in this example, a shutter 22 whose main surface is formed by a member which is close to the base on the side opposite to the side observed by the infrared thermometer and which is sufficiently specular with respect to the measurement wavelength of the infrared radiation thermometer. During the temperature measurement of the base 10 by the infrared radiation thermometer 15, the stray light is blocked so as not to enter.

As described above, the role of the shutter mechanism is to firstly correct the increase in the apparent emissivity due to the radiation light from the wafer reflected by the metal film when the metal film is formed on the wafer substrate. And secondly, infrared radiation
Improving measurement accuracy by improving light intensity
Third, stray light is blocked.

FIG. 6 is a schematic configuration diagram of the stage 6 of FIG. 4, and has basically the same configuration as the stage 7 of FIG. The stage 6 has a built-in heater 18 and has a structure in which a heat transfer gas flows in a space between the stage 6 and the base 10 in a vacuum, and a clamp 17 for bringing the heat transfer gas into uniform contact with the base. is set up. Base 1
An opening window 19 for measuring a temperature of 0 with an infrared radiation thermometer 14 and a stray light blocking cylinder 16 are connected.
Window plates 23 and 24 made of a material that transmits infrared rays are attached to both ends of 6. Further, the cylinder 16 is heated and cooled by water so as not to become a source of stray light. In order to further reduce the influence of stray light, the inner wall of the cylinder 16 can be subjected to black body treatment after cooling . Also, in this example, a shutter 21 is provided close to the base 10 similarly to the case of FIG.

Note that the shutter has (1) infrared radiation
Specular infrared reflectance for measurement wavelength of thermometer
Ones, (2) may be any structure as long as it has a shutdown function of the stray light, structure, or the fixed shutter to a region of the chamber for opening and closing freely driven for example in synchronization with the temperature measurement timing of the base Various configurations such as a mechanism for moving the substrate to the lower part of the shutter at the time of measurement can be adopted.

FIG. 7 is a characteristic curve showing the difference in the infrared emissivity of the silicon wafer base with and without the shutter.
FIG. 7A is a comparative example without a shutter, and FIG.
4 shows the measurement results of the present example in which a shutter was provided. As apparent from this, the apparent infrared emissivity of the wafer before the aluminum Al film formation (without the Al film) in FIG.
Although the apparent infrared emissivity of the wafer after film formation (with an Al film) is smaller than the apparent infrared emissivity of the wafer, by installing a shutter on the wafer before the Al film formation, FIG.
As shown in (b), the apparent infrared emissivity was almost equal to that of the wafer after the Al film formation. Thus, it can be seen that by measuring the substrate temperature using the shutter, measurement can be performed at a constant emissivity.

<Embodiment 4> If 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) as shown in FIG. After the base 10 is heated or cooled by a stage 25 dedicated to heating or cooling separately provided at a location remote from the base 19, the base 10 is transported to a stage having an opening window 19, and the temperature is measured by an infrared radiation thermometer 27. The measurement can be performed in a state where the temperature distribution of the base 10 is more uniform.

Embodiment 5 When heating or cooling of the substrate is performed only from one of the front surface and the rear surface, a temperature difference occurs between the front surface and the rear surface of the substrate. Therefore, as shown in FIG. 9, the heating or cooling means 28, 2
The provision of 9 makes it possible to reduce the temperature difference between the two surfaces. This can also reduce the non-uniformity of the temperature distribution on the substrate due to the opening window 19.

<Embodiment 6> Another embodiment in which an aluminum Al film is formed on a silicon wafer substrate 10 by sputtering using the sputtering apparatus 1 of 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, measured by a thermocouple 12, and based on the temperature measured by an infrared radiation thermometer 11.
Then, the wafer is transferred to the substrate temperature adjusting chamber 3. The wafer substrate 10 transported to the substrate temperature adjustment chamber 3 is measured by an infrared radiation thermometer 14, cooled to a predetermined 200 ° C. by controlling the temperature of the stage 6, and transported to the sputter deposition chamber 4. The substrate 10 is sputtered in the sputtering film forming chamber 4 according to a temperature profile as shown in FIG. The target 8 had a composition of 1% Si-3% Cu-Al.

First, the temperature of the substrate 10 is controlled to 230 ° C., and a first sputter film is formed to a film thickness of about 100 ° C. Then, the sputtering is stopped once, and the substrate is transferred to the substrate temperature adjusting chamber 3. Is done. Substrate temperature adjustment chamber 3
Then, the temperature of the base 10 is controlled to 300 ° C. to grow crystal grains of the Al film obtained by the first sputter deposition to improve the orientation and the like. Next, the substrate is transported again to the sputtering film forming chamber 4, and after setting the substrate temperature to about 400 ° C., the second sputtering film formation is restarted and the film is formed to 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, the substrate is immediately transferred to the substrate temperature adjusting chamber 3 and rapidly cooled to about 50 ° C. Thereby, the deposition of Si and Cu in the Al sputtered film could be suppressed.

In the above embodiment, an example was described in which a silicon wafer was used as a substrate and an Al thin film was formed on the surface thereof by sputtering. Good crystallinity and
A fine structure of a thin film was obtained, and a high-quality film was formed. For example, when heating a thin film having a thickness of several hundred degrees 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, which can know an accurate temperature.

[0086] The vacuum processing apparatus of the present invention, in addition to the CVD of the sputtering apparatus (Chemica l Vapor Deposi
It is needless to say that the present invention can be applied to a film forming apparatus or the like according to the above method. For example, it is effective when a silicon wafer substrate is used as a base and a tungsten film is formed on the substrate by a known method by CVD. In this type of film forming apparatus, since the accuracy of the temperature control of the substrate affects the quality of the film to be formed, the film forming apparatus of the present invention includes:
We can respond to that.

Note that a film forming apparatus can be realized by using a vacuum processing chamber as a film forming processing chamber as in the above-described embodiment. And the temperature control of the substrate to be etched can be easily realized as in the above embodiment.

[0088]

As described above, according to the present invention, it is possible to accurately control the temperature of a substrate in a vacuum.
In addition, since the temperature during film formation can be easily controlled, a high-quality film can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a partial cross-section of a vacuum processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional configuration diagram illustrating an example of a sputtering stage.

FIG. 3 is a block diagram schematically showing a partial cross section of a vacuum processing apparatus according to another embodiment of the present invention.

FIG. 4 is a partial cross-sectional block diagram schematically illustrating a vacuum processing apparatus according to 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 adjustment 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 adjustment stage each provided with a shutter mechanism.

FIG. 7 is a characteristic curve diagram showing temperature measurement results depending on the presence or absence of 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 sectional view of a stage in which temperature control means are provided on both surfaces of a base.

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

[Description of Signs] 1 ... Vacuum processing apparatus, 2 ... Base temperature calibration chamber, 3 ... Base temperature adjustment chamber, 4 ... Sputter deposition chamber, 5 ... Base temperature calibration stage, 6 ... Base temperature adjustment stage, 7 ... Sputter stage 8 target, 9 sputter electrode, 10 base, 11, 14, 15 infrared radiation thermometer, 13 base temperature controller, 16 stray light blocking cylinder, 19 opening window, 20-22 shutter, GV1, GV2: Gate valves.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/31 H01L 21/302 A (72) Inventor Hideaki Shimamura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Production by Hitachi, Ltd. Within the Technical Research Laboratory (72) Inventor Susumu Tsutake Takeshi 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside of Hitachi, Ltd. Within Hitachi, Ltd. Production Technology Laboratory (72) Inventor Yuji Yoneoka 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Japan Hitachi, Ltd. Production Technology Laboratory

Claims (2)

[Claims] 1. A film forming method for controlling a temperature of a substrate on which a film forming process is to be performed and performing a film forming process on the substrate, wherein the substrate is formed during the film forming process and before the film forming process. Pseudo-inducing the infrared radiation characteristics presented later, measuring the radiation intensity of the substrate at a known temperature with a first infrared radiation thermometer, from the substrate in the pseudo state based on the known temperature Calculating an infrared sensitivity correction value for correctly obtaining the temperature of the substrate by the second infrared radiation thermometer from the output of the first infrared radiation thermometer measuring the radiation intensity of the first infrared radiation thermometer, and storing the correction value in the storage means. During and after the film forming process of the substrate to be measured under unknown temperature conditions,
Measuring the radiation intensity of the substrate with the second infrared radiation thermometer; and outputting the output from the second infrared radiation thermometer for measuring the radiation intensity of the substrate to the previously acquired infrared sensitivity correction value. And calculating a true temperature of the substrate by correcting the temperature based on the calculated temperature, and performing a film forming process by controlling the temperature of the substrate according to the calculated temperature. 2. A step of simulating the infrared radiation characteristic exhibited by the substrate during and after the film forming process before the film forming process is performed on the surface on the side where the substrate is subjected to the film forming process. 1
2. The film forming method according to claim 1, comprising a step of bringing a member substantially constituting a mirror surface close to the measurement wavelength of the infrared radiation thermometer.