Etching process is unstable? It must be because your temperature control system is not keeping up!
1. Temperature requirements of etching process
In semiconductor manufacturing, the etching process is a key process for accurately transferring photoresist patterns onto silicon wafers, and its quality directly determines the performance and yield of the product. Temperature changes can significantly affect the etching rate, selectivity, and process stability.
With the development of advanced processes, the temperature requirements of etching processes are becoming more and more stringent. Taking the 5nm and below processes as an example, the temperature fluctuation must be controlled within the ultra-precise range of ±0.05℃. Every 0.1℃ deviation may cause the etching rate to change by more than 1%, thus affecting the accuracy of key dimensions and the fidelity of pattern transfer.
2. Temperature control challenges faced by different etching processes
Dry Etch/RIE: In dry etching, the electrode temperature must be controlled within ±0.1°C - temperature fluctuations will significantly affect the uniformity of the plasma, resulting in unstable etching results. The chamber has very strict requirements for thermal balance, and local temperature differences exceeding 1°C may cause deformation of the etched profile. When etching with a high aspect ratio, the sidewall temperature gradient must remain stable, otherwise it is easy to cause deviations in the critical dimensions of the etched pattern.
Wet etching: The etching liquids used in wet etching are mostly strong acids and alkalis, which are not only extremely corrosive, but also produce drastic temperature changes when chemical reactions occur. Since the reaction rate is extremely sensitive to temperature changes, the temperature control response time of large-capacity tanks must be controlled within 30 seconds, and the temperature uniformity of the tank liquid must be better than ±0.3℃ .
Atomic layer etching/ALE: In the atomic layer etching process, the temperature switching response speed is required to achieve a transient control capability of 1°C/second, and the periodic temperature fluctuation must be suppressed within the range of ±0.05°C . In addition, since the process involves independent temperature control of multiple areas, the temperature difference between each area must be less than 0.3°C. These differentiated challenges require the temperature control system to have ultra-high precision, fast response capability and excellent operating stability.
3. Application of FerroTec temperature control equipment in etching process
FerroTec has been deeply involved in the temperature control industry for many years. With its ultra-high temperature control accuracy of ±0.01°C and efficient heat exchange performance, it has set an industry benchmark in the field of semiconductor temperature control. Its products have been widely used in the advanced process production lines of many top chip manufacturers in the world, helping to improve process stability and production efficiency.
FerroTec has developed a precision temperature control module specifically for semiconductor etching processes. The module adopts a unique dual-channel design and is equipped with an intelligent temperature control algorithm system. It can quickly switch to the corresponding temperature range according to the needs of different process stages, meeting the stringent requirements of the etching process for temperature control, thereby effectively improving the etching rate and process yield.
FerroTec temperature control solution for etching: During silicon etching, the FerroTec temperature control system stabilizes the wafer surface temperature within the set range through closed-loop control, keeps the etching rate deviation within 2%, and significantly improves the consistency of key dimensions. According to a report from a large domestic foundry, the CPK (process capability index) of the etching process has been significantly improved after adopting the FerroTec temperature control system. The following are some typical application cases.
