For controlling multivariable systems, a control unit for controlling a system with several coupled control variables. The control unit includes controllers (10, 11) having associated control variables (x.sub.1, x.sub.2) as well as a decoupling network. The decoupling network is connected upstream from the system and includes at least one first decoupling member (12). A first output variable (y.sub.1) of a first one of the controllers (10) is routed to the first decoupling member (12). The first decoupling member generates a first correcting quantity (14) for a second output variable (y.sub.2) of a second one of the controllers (11). The second controller (11) has a PI- or PID-controller core (40) and is configured such that integrator windup is eliminated when the second output variable (y.sub.2) corrected with the first correcting quantity (14) reaches a manipulated variable limit. Bumpless manual/automatic changeover of the controller is also made possible.

A hybrid cascade Model-Based Predictive control (MBPC) and conventional control system for thermal processing equipment of semiconductor substrates, and more in particular for vertical thermal reactors is described. In one embodiment, the conventional control system is based on a PID controller. In one embodiment, the MBPC algorithm is based on both multiple linear dynamic mathematical models and non-linear static mathematical models, which are derived from the closed-loop modeling control data by using the closed-loop identification method. In order to achieve effective dynamic linear models, the desired temperature control range is divided into several temperature sub-ranges. For each temperature sub-range, and for each heating zone, a corresponding dynamic model is identified. During temperature ramp up/down, the control system is provided with a fuzzy control logic and inference engine that switches the dynamic models automatically according to the actual temperature. When a thermocouple (TC) temperature measurement is in failure, a software soft sensor based on dynamic model computing is used to replace the real TC sampling in its place as a control system input. Consequently, when a TC failure occurs during a process, the process can be completed without the loss of the semiconductor substrate(s) being processed.

A floating substrate reactor allows heat treatment of a series of semiconductor substrates, one by one. The heat treatment occurs while flowing gas suspends a substrate between two heated surfaces of the reactor. The two heated surfaces each have multiple heating zones. The heating zones are heated to desired temperature(s) and a substrate is then loaded into the reactor for heat treatment. Upon loading, the relatively cold substrate absorbs heat and cools the process chamber. A heat spike, which can be varied, is applied to the heating zones to heat the reactor to the desired temperature again. The substrate, however, is unloaded from the reactor before the temperatures of the heating zones have reached the desired temperature. After the heating zones have reached the desired temperature, the next substrate in the series of substrates is loaded into the reactor for heat treatment. The heating rate of each heating zone is independently controlled by two nested control loops in a cascade temperature control configuration, permitting differences in the heating rates of the heating zone to be accounted for, thus allowing a uniform temperature or predetermined gradient to be established across all the heating zones. The intensity of the heat spike is recalculated after the introduction of each substrate, using the heating behavior of the previous heat spike as a calculation input, to more accurately heat the heating zones to the desired temperature. The variability of the heat spike intensity from substrate to substrate also allows the throughput of the heat treatment apparatus to be varied.

An apparatus and method for reversing ventricular remodeling with electro-stimulatory therapy. A ventricle is paced by delivering one or more stimulatory pulses in a manner such that a stressed region of the myocardium is pre-excited relative to other regions in order to subject the stressed region to a lessened preload and afterload during systole. The unloading of the stressed myocardium over time effects reversal of undesirable ventricular remodeling.

A single substrate reactor system for processing batches of product substrates one at a time is provided with at least one dummy substrate. In the time after one batch of product substrates is processed and before another batch of product substrates is ready for processing, the dummy substrate is used as a substitute for the thermal load presented by a product substrate. The dummy substrate is loaded into and unloaded from the reactor in the same manner as a batch of product substrates. Advantageously, the thermal load presented by the dummy substrate maintains the thermal equilibrium established during the processing of a batch of product substrates, thereby eliminating the need for and time required to re-establish this equilibrium at the beginning of processing the next batch of substrates.