Chapter 1
Why temperature control is important in semiconductor manufacturing
In semiconductor manufacturing, temperature is involved in various processes such as material state, reactions, film deposition, diffusion, and heat treatment. Depending on process, even slight changes in temperature conditions can affect product characteristic and process repeatability. Therefore, it is important not only to approach the target temperature but also to be able to stably reproduce the same conditions.
Temperature conditions affect quality and yield.
In semiconductor manufacturing, the thermal history and temperature conditions applied to materials differ at each stage of process. If the temperature is not properly controlled, it can lead to variations in process conditions and differences in quality.
Therefore, it is important to consider not only measuring the temperature, but also comparing it with the set conditions, recording the temperature history, monitoring for anomalies, and implementing necessary control as a complete process.
Temperature stability is essential for repeatability of process conditions.
To repeatedly use the same manufacturing conditions, it is crucial to be able to stably reproduce process state. Among these conditions, temperature changes depending on equipment conditions, workpiece conditions, and sensor mounting status, so it is necessary to clearly define which location's temperature needs to be controlled.
It's not just about measuring temperature; it's also about recording, monitoring, and control
A single point in time measurement may not be sufficient to determine when an anomaly occurred or how it changed. Recording temperature history and connecting it to alarms or remote monitoring as needed can help in detecting process anomalies and identifying their causes.
For an overview of the overall approach to measurement in semiconductor manufacturing, please also see "What is Semiconductor Measurement?".
Chapter 2
At which process of semiconductor manufacturing is temperature control necessary?
In semiconductor manufacturing, temperature control methods and measurement targets vary depending on process. Here, we will summarize some typical process to consider when thinking about temperature control.
Crystal growth and single crystal pulling
In crystal growth, in addition to stably measuring temperatures in the high-temperature range, it is necessary to consider the measurement location, observation conditions, and the furnace environment.
radiation thermometer for silicon single crystal pulling furnaces
Oxidation, Diffusion, CVD
It is important to organize information such as furnace temperature, measurement location, sensor shape, temperature history, and control status to perform temperature measurements that are appropriate for process conditions.
What is temperature measurement in diffusion furnaces and CVD furnaces?
Thin film formation, heat treatment, and annealing.
It is important to stably manage temperature conditions such as heating, holding, and cooling to ensure process repeatability and quality control.
In addition to the equipment's control conditions, it's also necessary to check the actual measurement locations and temperature history.
CMP/polishing
In polishing process, there are situations where it is difficult to measure objects that are difficult to contact or phenomena that change rapidly. Non-contact temperature measurement and real-time monitoring may be suitable options.
Cleanroom and storage environment
In addition to process itself, it is also important to continuously record and monitor temperature/humidity of the cleanroom and storage environment.
Chapter 3
To accurately measure the temperature in semiconductor manufacturing
When measuring temperature in semiconductor manufacturing, it's important not to simply think, "We have a thermometer, so we can measure it," but rather to organize factors such as the object to be measured, the measurement location, the temperature range, the response time, whether contact is possible, and the surrounding environment.
Situations in which contact temperature sensors are used
If you can attach a sensor to the object, or if you want to directly measure the temperature of the object, contact-type temperature sensors such as thermocouples or resistance thermometer are suitable options.
In high-temperature process, it is also necessary to check the sensor's material, protective structure, installation location, insertion depth, and replaceability.
View the temperature sensor guide.
Situations where radiation thermometer is used
Non-contact temperature measurement using radiation thermometer is a viable option when it is difficult to touch the object, when measuring high-temperature objects, moving objects, or surface temperatures.
During the selection process, we check factors such as temperature range, measurement distance, target size, emissivity, measurement window, and surrounding environment.
View radiation thermometer guide
We need to consider furnace temperature, wafer temperature, and surface temperature separately.
The temperature you see on the control may not match the actual temperature of the workpiece or wafer you want to manage. It is important to clarify which location temperature is used as the standard for process management.
Manage temperature distribution, multi points measurement, and temperature history.
Temperature differences can occur within furnaces and equipment depending on the location. To identify temperature variations that cannot be seen with a single point of measurement, multi points measurement and temperature distribution analysis are effective.
Furthermore, it is important to record temperature history in order to identify the cause of any abnormalities and to maintain quality records.
Checklist when choosing a temperature measuring device
| Check items | What I want to confirm |
|---|---|
| What to measure | Where should the measurements be taken: inside the furnace, on the wafer, on the crystal, on the surface, or around the equipment? |
| Temperature range | Check not only room temperature, but also the peak temperature and the temperature during abnormal conditions. |
| Measurement location | Confirm which temperature will be used as the representative temperature for management and whether it is possible to install it. |
| Possibility of contact | Can the sensor be brought into contact with the object, or is non-contact measurement required? |
| response speed | At what rate should we track temperature changes? |
| Recording and monitoring | Are features such as history saving, alarms, remote monitoring, and report generation necessary? |
| Calibration and certification | How much proof is required based on quality assurance, audits, customer requirements, etc.? |
For a general guide on choosing temperature measuring equipment, please also see "How to Choose Temperature Measuring Equipment".
Chapter 4
Calibration that supports the reliability of measurement values
When using temperature measurements in semiconductor manufacturing for process control, quality assurance, auditing, and research and development, it is crucial to be able to explain "how reliable those measurements are."
Why is the reliability of measurement values important in semiconductor manufacturing?
If temperature conditions are used to determine the course of process, inaccurate indicated value from measuring instruments can lead to discrepancies between the actual conditions and the recorded values. Therefore, it is necessary to check the condition of the measuring instruments and the reliability of the measured values according to the application.
Calibration and adjustment/inspection are not the same thing.
Calibration is the process of verifying the relationship between the value indicated by a measuring instrument and a reference value. Calibration itself does not mean correcting indicated value of the measuring instrument.
In actual operation, adjustments or replacements may be considered depending on the calibration results. It is important to organize calibration, inspection, and adjustment according to their respective purposes.
What is traceability?
To explain the reliability of measurement values, it is sometimes necessary to verify which standards the standards used and calibration results are linked to. For quality assurance and audit compliance, organizing the scope of necessary certificates and traceability in advance makes it easier to select a calibration method.
How should we consider the calibration cycle?
It is important to consider the calibration cycle not by setting a uniform cycle for all measuring instruments, but by taking into account factors such as the operating environment, frequency of use, importance, past calibration results, and requirements.
How do you determine the calibration cycle?
How to differentiate between JCSS calibration and general calibration
The required level of certification varies depending on the instrument's application, customer requirements, and audit requirements. It's important to select and define the necessary calibration range rather than calibrating all instruments in the same way.
Let's look at the difference between JCSS calibration and general calibration.
The basics of calibration itself are explained in detail in "What is calibration?".
Chapter 5
Common challenges in temperature control during semiconductor manufacturing
display temperature is stable, but the quality is unstable.
The temperature detected by the sensor may not match the actual temperature of the workpiece or equipment you want to monitor. It is important to review the measurement location and method.
Let's look at temperature measurement and the principles for accurate measurement.
The temperature varies depending on the location inside the furnace.
Measuring the temperature at a single point may not provide a complete picture of the temperature distribution inside the furnace. Therefore, we will examine the measurement location, perform multi points measurements, and review the temperature history.
What is temperature measurement in diffusion furnaces and CVD furnaces?
Temperature sensors degrade in high-temperature process.
In high-temperature environments, the sensor's structure and working conditions may degrade, potentially affecting the reliability of the measurement results.
Non-contact measurement values are unstable.
It is necessary to check conditions specific radiation thermometer such emissivity, measurement distance, target size, measurement window, and surrounding environment.
We have the measurement data, but we can't trace the cause afterward.
In addition to checking the measured values on the spot, recording temperature history, alarms, and equipment status makes it easier to identify the cause of an anomaly and prevent its recurrence.
The furnace temperature is unstable.
It is necessary to isolate and check multiple factors, such as sensors, heaters, insulation, control conditions, and workpiece conditions.
Let's look at the causes and countermeasures for unstable furnace temperatures.
Chapter 6
Chino can support semiconductor temperature management.
Chino supports everything from measurement to control in semiconductor manufacturing by combining temperature sensors, radiation thermometer, recorders, controllers, temperature/humidity monitors, calibration equipment and standard sensors, and calibration services.
| Role | Main equipment and services | Way of thinking |
|---|---|---|
| Measure | Temperature sensors, radiation thermometer, thermal image measurement | The method is selected based on factors such as the object to be measured, temperature range, measurement location, whether contact is permitted, and response speed. |
| Record | Recorder, data logger | Temperature history and data from abnormal situations are recorded and used for process verification and root cause investigation. |
| Monitor | Surveillance systems, wireless equipment | We continuously monitor temperature/humidity, and equipment status to identify any abnormalities or changes. |
| Control | Controllers, instrumentation systems | Based on the measured values, process conditions are adjusted to approach the target temperature. |
| Calibration | Temperature calibration equipment, standard sensors, calibration services | It verifies the reliability of measurement values and the required certification level, supporting quality control. |
Learn more about semiconductor manufacturing
Learn more about temperature control
Chapter 7
Things to check when considering temperature control in semiconductor manufacturing
When considering temperature measurement and monitoring, it's easier to determine the necessary configuration if you first organize the measurement target and process conditions rather than searching by product name.
| Check items | Things to organize |
|---|---|
| process and measurement target | What aspects should be measured, such as crystal growth, CVD, diffusion, heat treatment, CMP, storage, and cleanrooms? |
| Temperature range | The required measurement range, including room temperature, peak temperature, and abnormal temperature. |
| Measurement location | Which location—the furnace interior, wafer, crystal, surface, or surrounding equipment—should be used as the representative value for management? |
| Possibility of contact | Is it possible to measure it using contact, or is non-contact measurement required? |
| response speed | How quickly do we need to track temperature changes? |
| Recording and monitoring | Do you need features such as history saving, alarms, remote monitoring, and reporting? |
| Calibration and certification | How much proof is required based on quality assurance, audits, customer requirements, etc.? |
Consult about temperature measurement, monitoring, and calibration in semiconductor manufacturing.
You can consult with us based on the information you have available, such as process, the object to be measured, the temperature range, the measurement method, whether recording and monitoring are necessary, and the calibration conditions.
Consult about technology and productsFAQ
FAQ
Why is temperature control so important in semiconductor manufacturing?
This is because there are many processes—such as crystal growth, diffusion, CVD, and heat treatment—where temperature conditions affect the state of process and repeatability, as well as process. It is important to measure temperature and, as necessary, record, monitor, and manage it—including control.
What kind of thermometers are used in semiconductor manufacturing?
Potential options include contact-type temperature sensors such as thermocouples and non-contact temperature measurement devices such as radiation thermometer. Selection should be based on factors such as the object to be measured, temperature range, measurement location, whether contact is possible, and response speed.
Are the furnace temperature and the workpiece temperature the same?
They are not always the same. Depending on the sensor's location, the temperature distribution inside the furnace, the material and shape of the workpiece, etc., there may be a difference between the temperature control is observing and the actual temperature of the object you want to manage.
Why do thermometers need to be calibrated?
This is to confirm the relationship between the value shown by the measuring instrument and the reference value, and to maintain the reliability of the measured value. When using measured values for quality control, audits, or comparison of process conditions, calibration management appropriate to the application should be considered.
Do all thermometers need to be JCSS calibrated?
It's not always necessary to set a uniform standard. It's important to consider the required certification level based on factors such as the instrument's intended use, its importance for quality assurance, customer requirements, and audit requirements.
What kind of information would make it easier to choose a temperature measuring device?
Organizing the measurement target, temperature range, measurement location, required accuracy, whether contact is permitted, response speed, whether recording and monitoring are necessary, and whether calibration and certification are required will make the planning process easier.
