Things to keep in mind when measuring the temperature of diffusion furnaces and CVD furnaces
When measuring temperatures in diffusion furnaces and CVD furnaces, it's not enough to simply measure the temperature inside the furnace; it's crucial to organize which temperature points to measure, what type of sensor to use, and how to use that information for control and recording.
- Measurement location: Clearly define the location of the temperature you want to control, such as near the furnace wall, near the heater, or near the object being processed.
- Sensor shape: Depending on the furnace shape and insertion direction, we will consider profile shape, L-shape, spike shape, etc.
- Relationship with control: If there is a time difference in heat conduction from the heater to the wafer, control method needs to be considered.
- Recording and Monitoring: We will implement a system to record temperature history and control status, allowing us to detect abnormalities and changes.
Why temperature measurement is important in diffusion furnaces and CVD furnaces
In semiconductor manufacturing process, even slight differences in heat treatment conditions can affect quality and repeatability. In diffusion furnaces and CVD furnaces, it is crucial to stably monitor the temperature, temperature distribution, and heating, holding, and cooling conditions within the furnace.
In particular, if it takes time for heat to transfer from the heater inside the furnace wall to the vicinity of the wafer, control process based solely on the temperature near the heater may result in a discrepancy between the temperature change and that of the material being processed. In such cases, it is necessary to consider both the measurement location and control method together.
Temperature measurement is not merely a means of determining temperature (process). By analyzing the measured values (control), recording and monitoring the results (control), and using them to make improvements as needed (process), it serves as a basis for management decisions ( ).
Reasons why quartz protective tube thermocouples are used
In high-temperature furnaces such as diffusion furnaces and CVD furnaces, it is necessary to measure temperature while protecting the thermocouple from the furnace environment. Quartz protective tube thermocouples are used to protect the thermocouple according to the measurement conditions inside the furnace and to measure the temperature at the desired location.
The appropriate shape varies depending on the furnace structure, insertion direction, and the location to be measured. Chino offers a variety of quartz protective tube thermocouple shapes to suit the configuration of diffusion furnaces and CVD furnaces.
| Shape examples | Main idea | Things I want to confirm |
|---|---|---|
| Profile thermocouple | It is sometimes used to determine the temperature distribution inside a furnace or to understand the temperature at multiple locations. | Number of measurement points, measurement location, insertion direction, furnace space |
| L-shaped thermocouple | This approach is considered when you want to position the measurement unit closer to the target location, in accordance with the furnace structure and the location of the insertion port. | Bending shape, insertion length, fixing method, presence or absence of interference |
| Spike-type thermocouple | The shape will be considered based on the measurement location and mounting conditions. | Contact condition, protective tube shape, operating temperature, replaceability |
Points to check when measuring furnace temperature
When measuring the temperature in diffusion furnaces and CVD furnaces, it is necessary to check not only the temperature range, but also the measurement location, responsiveness, furnace atmosphere, and sensor mounting conditions. If the sensor shape is not suitable for the object being measured, it will be difficult to accurately determine the required temperature.
| Check items | Contents to be confirmed |
|---|---|
| Measurement purpose | We will organize the uses of the measured values, such as understanding the furnace temperature, confirming the temperature distribution, inputting data for control, and recording quality. |
| Measurement location | Determine which locations you want to control the temperature of, such as the furnace wall, near the heater, or near the object being processed. |
| Furnace shape | We will check the insertion port, internal furnace space, interference with existing tools, and maintainability. |
| Temperature range | Check the normal operating temperature, maximum temperature, heating/cooling conditions, and usage time. |
| Recording and monitoring | We will organize the temperature history, alarms, abnormality checks, and whether coordination with control equipment and recorders is necessary. |
Consider temperature control and monitoring as well.
To stabilize the furnace temperature, it is also important how the values measured by thermocouples are used for control. If it takes time for heat to transfer from the heater inside the furnace wall to the wafer, operation may be delayed or insufficient in response to temperature changes in control object.
In such cases, it may be necessary to consider a combination of measurement location and control method, such as using a cascaded controller configuration. Additionally, centrally managing thyristor and controller information with a recorder makes it easier to review temperature history and control status later.
measure
Quartz protective tube thermocouple
Depending on the furnace shape and measurement location, we will consider profile-type, L-type, spike-type, and other configurations.
Control
Controllers
We will consider control multiple zones and temperature control tailored to characteristic of the furnace.
operation
Thyristor Regulators
We will consider configuration as operation equipment for heating systems, such as heater control.
Record and monitor
Recording and monitoring systems
Records temperature history, control status, and abnormalities to aid in quality control and cause identification.
What Chino can help with
At Chino, in addition to quartz thermocouples tailored to the shapes of diffusion and CVD reactors, configuration equipment related to temperature control, recording, and monitoring can be considered. By considering not only temperature but also control, monitoring, and records, it becomes easier to organize the information necessary for process management.
| region | Related equipment and configuration examples | Role |
|---|---|---|
| Temperature measurement | Quartz protective tube thermocouple | The temperature is measured according to the measurement location and furnace shape within the furnace. |
| Temperature control | Controllers | Based on the measured values, the heaters and other components control to stabilize the temperature. |
| Power control | Thyristor Regulators | It controls the power control to the heaters and supports the control configuration of the heating equipment. |
| Recording and monitoring | Recorders, monitoring systems | Temperature history and control status are recorded and used for anomaly detection and improvement. |
Things to organize before consultation
When consulting about furnace temperature measurement, the more information you have about the equipment conditions and measurement objectives, the easier it will be to consider suitable shapes and configuration. Even if the conditions are not yet finalized, organizing the following items will make the consultation process easier.
- Is the equipment in question a diffusion furnace, a CVD furnace, or a similar high-temperature furnace?
- Location and points to measure
- Furnace temperature range and normal operating temperature
- Shape, insertion direction, and mounting method of existing sensors
- Is it for control, recording, or checking temperature distribution?
- Is coordination with controllers, thyristors, and recorders necessary?
- Replacement frequency, maintenance methods, spare parts management
- Whether drawings, photographs, existing models, and working conditions are available.
Summary
When measuring temperatures in diffusion furnaces and CVD furnaces, selecting thermocouples that match the furnace shape and measurement location is crucial. In particular, if there is a time difference in heat transfer from the heater to the object being processed, the measurement location and control method must be considered together.
By combining quartz protective tube thermocouples, controllers, thyristor regulators, and recorders, you can consider temperature management that includes not only temperature measurement but also control, recording, and monitoring. Please consider configuration that suits your furnace after clarifying the equipment conditions and the temperature range you wish to manage.
FAQ
Why is temperature measurement important in diffusion furnaces and CVD furnaces?
This is because furnace temperature and temperature distribution affect repeatability and quality of processing conditions. Therefore, it is important to organize the locations where temperature is measured, the values used for control, and the information to be recorded.
What applications are quartz-protected tube thermocouples suitable for?
This is used when you want to measure temperature while protecting a thermocouple in a high-temperature furnace. In diffusion furnaces and CVD furnaces, the shape is considered according to the furnace shape and measurement location.
How do you choose between profile, L-shaped, and spike-shaped designs?
The design will be considered based on the furnace structure, insertion point, measurement location, presence of interference, and maintainability. Having drawings or information on existing components will facilitate the shape analysis.
Do you need a recorder in addition to a temperature measuring device?
If temperature history is required for quality control, anomaly detection, root cause tracing, or audit compliance, considering a temperature recorder or monitoring system is effective.
What should I prepare for the consultation?
Organizing information such as the type of furnace, measurement location, temperature range, shape of existing sensors, whether control and recording are required, and any drawings or photographs will make it easier to consider a suitable configuration.
I would like to consult about temperature measurement for diffusion furnaces and CVD furnaces.
Based on factors such as furnace shape, measurement location, temperature range, and whether control and recording are required, please consider a temperature measurement, control, and monitoring configuration that suits your application.
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