Untitled record

Method of measuring temperature in a heat treatment chamber

<p>10. . . Heat treatment system</p><p>12. . . Processing chamber</p><p>14. . . Wafer</p><p>15. . . Substrate holder</p><p>16. . . Cooling duct</p><p>18. . . Gas injection port</p><p>20. . . Gas outlet</p><p>twenty one. . . Rotation mechanism</p><p>twenty two. . . Heat source or heating device</p><p>twenty four. . . Heating lamp</p><p>25. . . Energy controller</p><p>27. . . Radiation detection device</p><p>28. . . optical fiber</p><p>30. . . Light detector</p><p>32. . . window</p><p>50. . . System controller</p><p>60. . . Thermocouple</p><p>62. . . Thermocouple holder</p>

A complete and capable description of the present invention, including the best way to do this, for a person familiar with this technology, more specifically described in the rest of the description, which is based on the attached drawings Narrative, where:

Figure 1 is a cross-sectional view of an example of a specific example of a heat treatment chamber, which can be used in accordance with the present invention;

Figure 2 is a schematic diagram of the coordinates of the result obtained in Example 1;

Figure 3 is a schematic diagram of the coordinates of the result obtained in Example 1;

Figure 4 is a schematic diagram of the coordinates of the result achieved in Figure 1;

Figure 5 is a diagram of the coordinates of the results obtained in Example 2; and Figure 6 is a diagram of the coordinates of the results obtained in Example 2.

Field of invention

The focus of the present invention is usually the method of measuring temperature in a heat treatment chamber. In a specific example, the method of measuring the temperature in the heat treatment chamber is used to calibrate the temperature detection device contained in the treatment chamber. The method of the present invention is particularly suitable for temperature measurement in a heat treatment chamber, whether it contains an oxidizing environment or a reducing environment.

Background of the invention

The heat treatment chamber used here relates to a device that can quickly heat an object, such as a semiconductor wafer. Such devices usually include a substrate holder for fixing one or more semiconductor wafers, and a light source for heating the wafers that emits light energy. During the heat treatment, the semiconductor wafer is heated under controlled conditions according to a preset temperature. During the heat treatment, various procedures can be completed in the heat treatment chamber, such as rapid thermal oxidation, nitridation, annealing, silicidation, sintering, and metal covering.

Many semiconductor heat treatment processes require heating a wafer to a high temperature, so that various chemical and physical transformations can be performed when the wafer is made into a device. During rapid thermal processing, for example, semiconductor wafers are usually heated to a temperature from about 300° C. to about 1200° C. with a row of heating lamps, and the time required is usually less than a few minutes. Among these procedures, one of the main goals is to heat the wafer as uniformly as possible.

During the rapid thermal processing of a semiconductor wafer, it is desirable to be able to monitor and control the temperature of the wafer. In particular, in all high-temperature wafer processes of current and foreseeable importance, it is important that the true temperature of the wafer be measured with a high degree of accuracy, repeatably and quickly. The ability to accurately measure the temperature of a wafer has a direct result in the quality and size of the integrated circuit being manufactured. For example, for a particular semiconductor device, the required minimum shape and size limits the calculation rate of the resulting microchip. In other words, the size of the shape is connected with the ability to measure and control the temperature of the device during processing.

One of the most significant challenges in wafer heating systems is the ability to accurately measure the substrate temperature during the heating process. In the past, various methods and devices for measuring the temperature of the substrate in the heat treatment chamber have been disclosed. Such devices include, for example, pyrometers, thermocouples that directly contact the substrate or are placed adjacent to the substrate, and use laser interferometers.

In order to use the various devices described above in a heat treatment chamber, the device usually needs to be calibrated. Therefore, various calibration procedures exist simultaneously to align the temperature readings of these devices with some absolute and correct temperature reference values. The latest technology and the most widely used temperature correction method in the heat treatment chamber is a semiconductor wafer that is placed in the processing chamber and has a thermocouple buried in the wafer. The temperature measurement value obtained from the thermocouple is compared with the temperature reading obtained from the temperature measurement device, and any difference can be corrected.

In the past, another method used to calibrate the temperature detection device in a heat treatment chamber is to heat the substrate to a specific temperature when a chemical or physical conversion is performed in the heat treatment chamber. By observing or measuring the ongoing chemical or physical conversion, the temperature of the heated substrate can be accurately measured, which can be used to calibrate other temperature detection devices included in the processing chamber. For example, in a specific example, the oxidation of silicon can be achieved by heating a silicon substrate in a processing chamber. The amount or degree of oxidation generated when the substrate is heated can indicate the temperature at which the substrate is revealed.

In addition to the oxidation of silicon, other calibration methods include ion implantation activation, such as arsenic ion (AS+) implants or boron difluoride ion (BF ₂ +) Implants, and oxidation of refractory metals, such as titanium and cobalt.

Compared with the method of using a thermocouple embedded in the semiconductor wafer, although the above method provides various advantages for calibrating the temperature detection device, the above calibration method is usually only useful in a higher temperature range. And it has not been used to calibrate a temperature detection device when the temperature is lower than about 500°C. At present, an increasing number of procedures are performed at lower temperatures, thus creating a need for accurate and precise temperature measurement methods in a lower temperature range. Therefore, there is a need to improve the calibration procedure of the temperature detection device included in the heat treatment chamber. In particular, there is a need to calibrate the temperature detection device program at lower temperatures and when various gases are circulated through the processing chamber.

Outline of Invention

The present invention also explains the aforementioned shortcomings and the structure and method of other conventional technologies.

Therefore, the object of the present invention is to provide an improved system and program for measuring the temperature of a semiconductor wafer in a heat treatment chamber.

Another object of the present invention is to provide a program for calibrating the temperature detection device contained in the heat treatment chamber.

Another object of the present invention is to calibrate the temperature detection device in the heat treatment chamber at a lower temperature and in the presence of oxidizing or reducing gas.

At the same time, another object of the present invention is to calibrate the temperature detection device in the heat treatment chamber when the treatment chamber is designed to contain water vapor during the heating process.

Another object of the present invention is to provide a procedure for measuring temperature in a heat treatment chamber, which uses a substrate with a copper surface, which forms a copper oxide coating during heating, and in which the steel oxide coating The thickness shows the temperature in the processing chamber.

These and other objects of the present invention are achieved by providing a procedure for measuring the temperature of a substrate in a heat treatment chamber. This procedure includes the steps of placing a substrate in a heat treatment chamber. In an embodiment of the present invention, the substrate includes a surface, which is a surface made of steel material. For example, the substrate may be a semiconductor wafer made of a material such as silicon. A copper cover layer can be adhered to the semiconductor wafer. The copper covering layer may have a thickness of, for example, at least 2000 angstroms, and in particular from about 2000 angstroms to about 1 micron.

After the substrate is placed in the heat treatment chamber, it will be heated for a preset period of time in an environment where an oxidant exists. In particular, the substrate can be heated to a predetermined maximum temperature very quickly and maintained at this temperature for a period of time. The temperature to which the substrate is heated must be sufficient to allow a coating of oxidized copper to be formed on the surface of the substrate.

According to the present invention, in order to determine the temperature to which the substrate is heated, the thickness of the oxidized cover layer is then measured. The thickness of the oxidized cover layer can be measured according to various methods, for example, using a spectroscopic ellipsometry. According to the thickness of the oxidized copper coating, the temperature can be measured.

It is generally believed that the procedure of the present invention can be used with various types of heat treatment chambers. In a preferred specific example, the heat treatment chamber used in the procedure of the present invention contains a multi-purpose light energy source, which is designed to heat the wafers placed in the treatment chamber. As mentioned above, in this specific example of the present invention, the program is designed to display the temperature in a heat treatment chamber when the treatment chamber contains an oxidizing environment.

For example, when there are gases such as water vapor, oxygen, and/or nitrogen oxide in the processing chamber, the present invention is very suitable for measuring the temperature of the substrate in a processing chamber. During the construction of an integrated circuit, in order to complete various procedures, these gases can be circulated through the processing chamber. However, these gases can interfere with the temperature measurement performed in the processing chamber. The present invention is designed to take into account any such differences, and therefore can be used to calibrate the temperature detection device in the processing chamber.

For example, to measure the temperature of the substrate according to the procedure described above, the temperature detection device included in the processing chamber can be calibrated according to the temperature measured by the thickness of the oxidized cover layer. The temperature detection device included in the heat treatment chamber can be, for example, a thermocouple and/or a pyrometer. Among its special advantages, the program of the present invention has been found to be particularly suitable for calibrating the temperature detection device when the temperature is lower than 600°C, and especially when the temperature is lower than about 500°C.

In addition to calibrating the temperature detection device, the program of the present invention can also be used to determine whether a substrate placed in the processing chamber is uniformly heated. For example, the thickness of the covering layer of oxidized copper can be measured at multiple locations on a substrate. If the thickness of the cover layer on the surface of the substrate is fixed, the substrate is uniformly heated. However, if the thickness of the cover layer is not fixed, it may indicate that the substrate is not uniformly heated over the entire surface. If this is the case, according to the measurement of the present invention, the heating device used with the heat treatment chamber can be adjusted and corrected accordingly. For example, if the primary energy source is used to heat the substrate in the processing chamber, in order to uniformly heat the substrate, the radiation distribution of the primary energy source can be adjusted.

In addition to being used to measure temperature in an oxidizing environment, an alternative specific example of the present invention is focused on a program that is used to measure temperature in a reducing environment. In this specific example, instead of containing a copper coating, the substrate placed in the heat treatment chamber contains an oxidized copper coating. If it is heated in a reducing environment, the oxidized copper coating will be reduced to copper, in other words, the thickness of the coating will be reduced. The reduced thickness of the oxidized copper cover layer is measured, which can be used to determine the temperature to which the substrate is heated. Similar to the specific example described above, this procedure is particularly suitable for measuring temperatures below about 600°C. The reducing environment in which this procedure is achieved can be generated by injecting a reducing gas, such as hydrogen, into the processing chamber. Hydrogen usually circulates through the hot cavity, so that various processes can be completed on the semiconductor wafer. Such procedures include, for example, sintering and covering metals.

Other objects, features and contents of the present invention will be described in more detail below.

Schematic description

A complete and capable description of the present invention, including the best way to do this, for a person familiar with this technology, more specifically described in the rest of the description, which is based on the attached drawings Narrative, where:

Figure 1 is a cross-sectional view of an example of a specific example of a heat treatment chamber, which can be used in accordance with the present invention;

Figure 2 is a schematic diagram of the coordinates of the result obtained in Example 1;

Figure 3 is a schematic diagram of the coordinates of the result obtained in Example 1;

Figure 4 is a schematic diagram of the coordinates of the result achieved in Figure 1;

Figure 5 is a diagram of the coordinates of the results obtained in Example 2; and Figure 6 is a diagram of the coordinates of the results obtained in Example 2.

The reference symbols used repeatedly in this description and the drawings are to represent the same or similar features or components of the present invention.

Detailed description of specific examples of preference

For a person familiar with this technology, it is necessary to understand that this discussion is only an illustration of a specific example, not to limit the broader morphology of the present invention, and the broader morphology is specifically realized in the structure of the example.

Generally, the focus of the present invention is on a method and apparatus for measuring the temperature of an object, especially a semiconductor wafer, in a heat treatment chamber during heat treatment. The system of the present invention is particularly suitable for measuring the temperature of a semiconductor wafer at a relatively low temperature in an oxidizing or reducing environment, for example, a temperature below about 600°C. The program of the present invention has been found to produce very accurate temperature measurements, which can be used to calibrate other temperature detection devices that can be found in the heat treatment chamber. When a semiconductor wafer is heated, the present invention can simultaneously provide information on the degree of uniformity of the temperature that can be reached. This information can be used for adjustments and changes in the equipment used to heat the wafer.

According to the present invention, in order to measure the temperature of an object in a heat treatment chamber, a substrate with a reactive coating layer is placed in the treatment chamber. For example, in a specific example, the substrate may be a silicon wafer with a copper covering layer adhered to a surface of the wafer. After being placed in the heat treatment chamber, the covered substrate is heated in an oxidizing environment, and the copper coating is partially oxidized. Then use a suitable device to measure the thickness of the copper oxide. Because the growth of copper oxide is related to temperature, the temperature can be measured and calculated based on the thickness of the copper oxide, which can then be used to calibrate other temperature detection devices included in the processing chamber. Furthermore, the uniformity of the copper oxide thickness on the wafer can be converted into the uniformity of the temperature on the wafer.

In an alternative specific example, the substrate may be pre-covered with a copper oxide coating, and then the substrate may be heated in a reducing environment relative to an oxidizing environment. In a reducing environment, copper oxide is converted to copper, so that the thickness of the copper oxide coating layer is reduced. By measuring the decrease in the thickness of the copper oxide cover layer, the temperature at which the substrate is heated can be accurately measured.

Various procedures are completed in the heat treatment chamber, such as oxidation, nitridation, annealing, metal covering, sintering, silicidation and various other procedures. In each procedure, not only the operating temperature is different, but also a variety of different gases circulate through the processing chamber. It is well known that reacting to the surrounding environment, or in other words, the specific gas circulating through the processing chamber, when the substrate is heated, will drastically affect the temperature of a substrate and the rate of temperature change. The procedure of the present invention is focused on measuring the temperature in the heat treatment chamber when various types of gases are present. This temperature information can then be used to calibrate temperature detection devices found in the processing chamber, which are used to monitor the temperature of the wafer in the processing chamber.

According to the present invention, when calibrating the temperature detection device found in the processing chamber, it is more preferred that the procedure of the present invention is completed under the conditions as close to the real procedure as possible. In this way, accurate and reliable temperature information can be generated, which can then be used to calibrate temperature instruments in the processing chamber in a specific program.

It will be clearer from the following description that the system of the present invention provides many advantages compared with the structure of the conventional technology. For example, the procedure of the present invention may not only be used to measure a wide temperature range, it is also particularly suitable for monitoring relatively low temperatures, such as temperatures below about 600°C. Furthermore, this procedure is very reliable, simple and correct. Finally, as described above, the system of the present invention is not only used to measure the temperature in the heat treatment chamber, but is also very suitable for measuring whether the objects in the treatment chamber are uniformly heated.

Referring to FIG. 1, for illustrative purposes only, it shows a specific example of a heat treatment system 10, which is used to heat treat one or more wafers made of semiconductor materials, such as silicon. The system 10 includes a processing chamber 12 suitable for receiving a substrate, such as a wafer 14 for various processes.

As shown in the figure, the wafer 14 is placed on a substrate holder 15, which is made of a thermally insulating material, such as quartz. The processing chamber 12 is designed to heat the wafer 14 at a very fast rate and under carefully controlled conditions.

The processing chamber 12 can be made of various materials, including metals and ceramics. For example, the processing chamber 12 may be made of stainless steel or quartz.

When the processing chamber 12 is made of a thermally conductive material, the processing chamber preferably includes a cooling system. For example, as shown in Figure 1, the processing chamber 12 includes a cooling duct 16 surrounding the processing chamber. The duct 16 is adapted to circulate a cooling fluid, such as water, which is used to maintain a fixed temperature of the walls of the processing chamber 12.

The processing chamber 12 may simultaneously include a gas injection port 18 and a gas outlet 20 for introducing a gas into the processing chamber and/or maintaining the processing chamber within a predetermined pressure range. For example, a gas can be introduced into the processing chamber 12 through the gas injection port 18 to react with the wafer 14. After the processing is completed, the gas can be discharged from the processing chamber using the gas outlet 20.

In addition, an inert gas can be injected into the processing chamber 12 through the gas injection port 18 to prevent any unwanted or undesirable side reactions from occurring in the processing chamber. In a further specific example, the gas injection port 18 and the gas outlet 20 can be used to pressurize the processing chamber 12. When needed, a vacuum can also be created in the processing chamber 12, which uses a gas outlet 20 or an additional and relatively large outlet, which can be located below the wafer plane.

During processing, in a specific example, the substrate holder 15 is configured to use a wafer rotation mechanism 21 to rotate the wafer 14.

Rotating the wafer can promote better temperature uniformity over the surface of the wafer and promote better contact between the wafer 14 and any gas introduced into the processing chamber. However, it must be understood that in addition to wafers, the processing chamber 12 is also suitable for processing optical parts, films, fibers, ribbons and other substrates of any shape.

A heat source or heating device 22 is usually contained in the processing chamber 12 and connected together to heat the wafer 14 during processing. The heating device 22 includes a multi-purpose heating lamp 24, such as a tungsten halogen lamp. As shown in FIG. 1, the heating lamp 24 is placed on the wafer 14. However, it must be understood that the heating lamp 24 can be placed in any position. Furthermore, if necessary, additional heating lamps may be included in the system 10, such as under the wafer 14.

It is generally preferred to use the heater lamp 24 as the heat source. For example, heating lamps have a higher heating and cooling rate than other heating devices, such as electrical components or traditional heating furnaces. The heating lamp 24 produces a rapid constant temperature treatment system that provides instant energy and usually requires a very short and well-controlled start period. The flow of energy from the heater lamp 24 can suddenly stop at any time. As shown in the figure, the heater lamp 24 is equipped with a progressive energy controller 25, which can be used to increase or decrease the heat energy emitted by the heater lamp.

As shown in FIG. 1, in this specific example, the system 10 includes a window 32 which is placed between the heating lamp 24 and the heat treatment chamber 12. The function of the window 32 is to separate the heater lamp 24 from the wafer 14 and prevent contamination of the processing chamber.

In order to monitor the temperature of the wafer 14 during the heating process, the heat treatment chamber 12 may include various and multiple temperature detection devices. For example, as shown in FIG. 1, the heat treatment chamber 12 may include a thermocouple 60, which is included in a thermocouple holder 62. The thermocouple 60 may be placed adjacent to the semiconductor wafer 14 or may be placed in direct contact with the wafer.

During heating, the thermocouple 60 can directly measure the temperature of the wafer.

In addition to or in addition to using the thermocouple 60, the system 10 may also include one or more radiation detection devices 27 for monitoring the temperature of the wafer 14 during thermal processing. The use of radiation detection devices to monitor the temperature of the wafer 14 is particularly suitable for applications where the emissivity of the wafer is known, and the temperature at which a wafer is essentially opaque, which is usually relatively low. High temperature.

The radiation detection device 27 includes an optical fiber or light pipe 28 which is connected to the opposing light detector 30 in sequence. The optical fiber 28 is designed to accept the thermal energy emitted by the wafer 14 at a specific wavelength. The detected amount of radiation is transmitted to the light detector 30, which generates a usable volt voltage signal for measuring the temperature of the wafer, part of which can be calculated according to Planck's Law. In a specific example, each optical fiber 28 is connected to a photodetector 30 composed of a pyrometer.

In addition to using thermocouples and radiation detection devices, other temperature detection devices can be included in the processing chamber of the present invention without limitation.

As shown in FIG. 1, the system 10 may further include a system controller 50, which may be, for example, a microprocessor. The controller 50 may be placed in a position where the thermocouple 60 and the light detector 30 are connected together. In particular, the controller 50 can be designed to receive the volt voltage signal from the temperature detection device, which can indicate the temperature of the wafer 14.

The system controller 50, as shown in FIG. 1, can also be connected with the heater lamp energy controller 25. In this arrangement, the controller 50 can measure the temperature of the wafer 14 and, based on this information, it can control the heat energy radiated by the heater lamp 24. In this way, the conditions for processing the wafer 14 in the reactor 12 can be adjusted in real time within a carefully controlled range.

In a specific example, the controller 50 can also be used to automatically control other components in the system. For example, the controller 50 may be used to control the flow rate of gas entering the processing chamber 12 through the gas injection port 18. As shown in the figure, the controller 50 can be further used to control the rotation rate of the wafer 14 in the processing chamber.

In order for the system 10 to operate effectively and correctly, it is important that the temperature detection device included in the heat treatment chamber can accurately measure the temperature of the semiconductor wafer when the semiconductor wafer is heated. Therefore, the temperature detection device must be calibrated to ensure that it can accurately monitor the temperature of the wafer. In particular, the temperature detection device is preferentially calibrated for various types of procedures performed in the processing chamber. As mentioned above, for example, circulating different gases in the processing chamber has a significant effect on the temperature of the wafer.

In order to calibrate the temperature detection device and to ensure that the wafer is uniformly heated, the focus of the procedure of the present invention is to accurately measure the temperature of a substrate. In particular, the focus of the procedure of the present invention is that there is an oxidized substrate in the processing chamber. In an environment or a reduced environment, accurately measure the temperature of a substrate.

For example, when monitoring the temperature of the substrate in an oxidizing environment, the procedure of the present invention focuses on using a substrate with a surface made of steel. When the substrate is placed in a heat treatment chamber and heated in the presence of an oxidizing gas, the surface of the steel is partially oxidized to form a layer of copper oxide. The amount of copper oxide formed in a fixed length of time is directly related to the temperature at which the substrate is heated. Therefore, according to the present invention, by measuring the thickness of the formed copper oxide coating layer, the temperature at which the substrate is heated can be accurately measured. This temperature can then be used to calibrate the temperature detection device present in the heat treatment chamber.

The substrate used in accordance with the present invention preferably has a shape similar to a semiconductor wafer. The substrate may be made entirely of copper, but it is preferable that it only contains a copper cover layer. For example, in a specific example, the substrate may be made of the same material as the semiconductor wafer to be processed in the processing chamber, such as silicon. A copper cover layer can be adhered to the wafer. In most applications, the copper covering layer must be at least 2000 angstroms thick, and especially from about 2000 angstroms to about 1 micron in thickness. However, the thickness of the cover layer actually used will depend on the temperature at which the substrate is heated, the process completed in the processing chamber, and the length of time the wafer is heated.

If necessary, an adhesive can be used in order to adhere the steel cover layer to the semiconductor wafer. In a specific example, the adhesive can also be used as a barrier to impurity to prevent the copper covering layer from contaminating the wafer made of semiconductor material and adhered to the copper covering layer. Examples of adhesives that can be used according to the present invention are titanium nitride (TiN), tantalum (Ta), and tantalum nitride (TaN).

As mentioned above, the copper coating used in the procedure of the present invention was found to be very suitable for temperature measurement in an oxidizing environment. Such an oxidizing environment is usually used for various processes in the heat treatment chamber. For example, many procedures are completed in a heat treatment chamber, in which an oxidized gas, such as oxygen, water vapor, or nitrogen oxide, circulates through the treatment chamber during the heat treatment. Preferably, when using the procedure of the present invention to calibrate the temperature detection device in a heat treatment chamber, the procedure of the present invention is completed under the same conditions as when processing semiconductor wafers. In particular, different gases circulating through the processing chamber will have different effects on the temperature. Therefore, it is preferred that the temperature that will be used to calibrate the temperature detection device is measured in the same environment that will be used to process the wafer.

Among the specific advantages, the procedure of the present invention is very suitable for measuring the temperature of the substrate in a lower temperature range in a heat treatment chamber, such as lower than about 600°C, and especially from about 400°C to about 550°C. °C. In the past, trying to monitor the temperature of the wafer at a lower temperature has experienced difficulties.

For example, pyrometers generally do not function very well when the temperature is lower than 500°C, because the wafer is partially transparent to electromagnetic radiation at low temperatures, which makes it difficult to measure the temperature of the wafer.

In addition to being very suitable for measuring the temperature of the substrate when the temperature is lower than 600°C, the procedure of the present invention is also very suitable for measuring the temperature of the substrate in an environment containing water vapor. Recently, oxidation procedures using water vapor have increased in importance. However, the way the water vapor is heated on the wafer and the way the temperature is monitored will have a significant impact. The program of the present invention provides a very precise and accurate temperature reference point when it is used to calibrate the temperature detection device in the processing chamber during water vapor oxidation.

According to the present invention, after the substrate containing the steel covering layer is placed in the heat treatment chamber and heated, in order to determine the temperature at which the substrate is heated, the thickness of the resulting copper oxide is measured. The method of measuring the thickness of the resulting steel oxide coating can vary depending on the specific application. This measurement can be done when the substrate is contained in the processing chamber or can be performed after the substrate is removed from the processing chamber.

In most applications, the thickness of the copper oxide coating must be measured using spectroscopic techniques. For example, in a specific example of the present invention, the thickness of the copper oxide coating layer can be measured using a spectroscopic ellipsometer.

The ellipsometer is a technique used to determine the properties of a material by reflecting the polarization characteristics of linearly polarized incident light from the surface of a material. The ellipsometer is very suitable for the procedure of the present invention, because copper and copper oxides, such as copper oxide (CuO) and cuprous oxide (Cu ₂ O) It has very different reflection characteristics, especially when the wavelength is greater than 5000 angstroms, and especially when the wavelength is greater than 7000 angstroms. When comparing the refractive index (n) and extinction coefficient (k) of copper and copper oxide, similar differences are also observed. Based on these differences and characteristics, the ellipsometer can be used to distinguish between copper and copper oxide, and to measure the thickness of the copper oxide coating formed on the surface of copper. However, it must be understood that other suitable methods for measuring the thickness of the copper oxide coating layer can be used in accordance with the present invention.

After the thickness of the copper oxide coating is measured, the temperature at which the substrate is heated can be easily calculated based on the time the substrate spends in the processing chamber. In most applications, the substrate of the present invention must be placed in a heat treatment chamber and heated at a rapid rate until it reaches the highest temperature stage. When heated to the highest temperature, the substrate can preferably be maintained at this temperature for a predetermined period of time, for example, less than about 10 minutes before cooling.

After the substrate is heated, the thickness of the copper oxide coating layer is then measured in order to determine the temperature at which the wafer is heated. In particular, a calibration curve for the temperature at a predetermined time can be established and used to determine the temperature. For example, knowing the thickness of the copper oxide coating and the amount of time the substrate is heated, a temperature can be measured from a predetermined calibration curve.

After the temperature of the substrate is measured based on the thickness of the oxide film, the measured temperature can be used to calibrate the temperature detection device included in the heat treatment chamber. For example, the temperature determined according to the procedure of the present invention can be used to calibrate the thermocouple 60 and/or the radiation detection device 27, as shown in FIG. 1.

Furthermore, by measuring the thickness of the steel oxide film at multiple locations, the ability of the heat treatment chamber to uniformly heat the substrate can also be measured. For example, if the thickness of the copper oxide cover layer is uniform, this processing chamber is to uniformly heat the substrate. However, if the thickness of the copper oxide cover layer is not uniform, it may indicate that the heater used to heat the substrate needs to be adjusted. For example, when using a light energy source as shown in Figure 1, in order to promote higher temperature uniformity, the radiation distribution formed by the light energy source can be changed.

In addition to measuring the temperature in an oxidizing environment, the focus of the present invention is also a procedure for measuring the temperature of the substrate in a reducing environment. In this specific example, a substrate with a copper oxide surface is used instead of a substrate with a copper surface. When the substrate is placed in a reducing environment and heated, the steel oxide will be reduced to copper, resulting in a reduction in the thickness of the steel oxide covering layer. Depending on the amount of time the substrate is heated, the reduced thickness of the cover layer can be converted into the temperature at which the substrate is heated. This temperature can then be used to calibrate other temperature detection devices that may be present in the heat treatment chamber, such as thermocouples and pyrometers.

In the heat treatment chamber, there is sometimes an environment that needs to be reduced for various procedures, including metal covering and sintering. Many of these procedures are performed at a temperature below 600°C, making the procedure of the present invention very suitable for temperature measurement. The reducing environment is generated by circulating gas, such as hydrogen, in the processing chamber.

The method for determining how much the thickness of the copper oxide is reduced can be the same as the method described above with respect to the temperature measured in an oxidizing environment. In particular, a spectroscopic ellipsometer can be used to measure the thickness of the oxide coating before and after the substrate is heated.

With reference to the following examples, the present invention will be understood more clearly.

Example 1

The following examples were completed to demonstrate copper and copper oxide (CuO) and sub-steel oxide (CuO) ₂ O) Comparison of differences in optical properties. In particular, the reflectance, refractive index (n), and extinction coefficient (k) of copper, copper oxide, and cuprous oxide are measured at different wavelengths. These measurements are done using a spectroscopic ellipsometer. These results are shown in Figure 2, Figure 3, and Figure 4.

As shown in the figure, the optical properties of copper are quite different from those of copper oxide and sub-steel oxide, especially at wavelengths greater than about 5000 angstroms, and especially at wavelengths greater than about 7000 angstroms.

These differences in optical properties make it relatively simple to accurately measure the thickness of the copper oxide coating formed on the surface of a steel. According to the present invention, since the thickness of such a covering layer can be easily and accurately measured, the temperature calculated according to the present invention can also be easily and accurately measured.

Example 2

The following example is directed to a specific example to obtain the time and temperature pattern of the copper oxide thickness. After constructing this graph, according to the present invention, according to the thickness of the cover layer, this graph can be used to determine the temperature.

In this experiment, a copper coating with a thickness of 8000 angstroms was placed on a silicon wafer with a diameter of 8 inches. The substrate covered by steel is placed in a heat treatment chamber, and it is heated to different temperatures and different lengths of time. In particular, some wafers are heated in the presence of oxygen or water vapor at various temperatures for 60 seconds. The oxygen and water vapor are injected into the processing chamber at a volume flow rate of 3 liters per minute. Oxygen and water vapor create an oxidizing environment.

Another set of wafers was heated to 400°C for different lengths of time in the presence of a gas containing oxygen molecules.

When the wafer is being processed, the temperature of the wafer is measured by the pre-calibrated control value.

When the substrate is heated, part of the copper coating is converted into copper oxide. The thickness of the copper oxide film formed on the substrate can be measured at different positions using a spectroscopic ellipsometer at a wavelength between 2000 and 8000 angstroms.

Refer to Figure 5 and Figure 6, which show the results of this example. As shown in the figure, the graph is built to show the relationship between temperature and copper oxide thickness when the wafer is heated for a predetermined length of time (Figure 5), and to show when the wafer is heated to a predetermined value. The relationship between temperature, time and oxide thickness (Figure 6). Figure 5 also shows the difference when the oxidizing environment in the processing chamber is changed.

The graphs shown in Figure 5 and Figure 6 provide a calibration line that can be used to determine temperature when other copper-covered wafers are being processed. For example, if a copper-covered wafer is heated to an unknown temperature for 60 seconds, this temperature can be determined by measuring the thickness of the cover layer, and a temperature can be obtained from the graph shown in Figure 5.

These and other modifications and changes of the present invention can be used in the field by those who have ordinary skills in this technology without departing from the spirit and scope of the present invention, which are described in more detail in the scope of the attached patent application. In addition, it must be understood that the topography of the various specific examples can be partially or entirely interchanged with each other. Furthermore, those who have ordinary skills in this technology will appreciate that the previous description is only described in an exemplary manner, rather than limiting the scope of the present invention in the further description of the attached patent application.

Symbol description of main components

10. . . Heat treatment system

12. . . Processing chamber

14. . . Wafer

15. . . Substrate holder

16. . . Cooling duct

18. . . Gas injection port

20. . . Gas outlet

twenty one. . . Rotation mechanism

twenty two. . . Heat source or heating device

twenty four. . . Heating lamp

25. . . Energy controller

27. . . Radiation detection device

28. . . optical fiber

30. . . Light detector

32. . . window

50. . . System controller

60. . . Thermocouple

62. . . Thermocouple holder