Method for recording a state of a cvd reactor under production conditions

A device with a chemical vapor deposition (CVD) reactor (1), and a controller (10) storing a formula that causes the controller (10) to:

• during each of one or more process steps (R1, R2, R3) of a process phase (PR), in which a substrate (2) is located in a process chamber (3) of the CVD reactor, and in accordance with first control data that is varied by a user, set at least one process temperature (T) and one process pressure (P), and feed a process gas flow (Q) into the process chamber (3);
• before or after the process phase (PR), and during each of one or more calibration or conditioning steps (C1.1, C1.2, C1.3) of a calibration or conditioning phase (PC, PC′), set at least one calibration or conditioning temperature (T) and one calibration or conditioning pressure (P), and feed a calibration or conditioning gas flow (Q) into the process chamber (3) in accordance with second control data that is not varied by the user;
• determine a current fingerprint from data measured by a plurality of sensors during the calibration or conditioning phase (PC, PC′);
• and
• compare the current fingerprint with a historical fingerprint.

A method for determining a plurality of values for a plurality of parameters for controlling a temperature of a surface of a substrate (2) supported by a susceptor (4) of a chemical vapor deposition (CVD) reactor (1) to a prescribed substrate temperature, in order to thermally treat the substrate (2) at the prescribed substrate temperature in at least one process step (R1) of a process phase (PR), wherein the plurality of parameters includes a first parameter (TS, LS) that is a heat input parameter, which affects a first heat flux (H1, H2) supplied from a heat source (6) to the susceptor (4), and a second parameter (TS, QC) that is a heat release parameter, which affects a second heat flux (H3, H4) dissipated from the surface of the substrate (2) to a heat sink (22), the method comprising:

• in a calibration phase (PC′) preceding the process phase (PR), determining a plurality of tuples in a plurality of calibration steps (C1.1, C1.2, C1.3), wherein each of the tuples includes a first value of the first parameter (TS, LS), a second value of the second parameter (TS, QC), and an actual temperature (TW) of the substrate surface that is obtained when the CVD reactor (1) is controlled with the first and second values;
• and
• forming a function (F), associating the actual temperature (TW) with at least one of the first or second parameters, from the plurality of tuples by means of an interpolation, from which function a temperature value (TW1) is obtained, which is correlated with the actual temperature (TW) of the substrate surface that comes closest to the prescribed substrate temperature.