TWI911845B - Method for temperature regulation of components for making a soldered or sintered joint, and soldering or sintering device - Google Patents

Abstract

The invention relates to a method for temperature regulation of components for making a soldered or sintered joint between said components, wherein at least one controllable heat source is provided for supplying thermal energy to be transferred to the components. A first temperature of a component, or of a component part of a soldering or sintering device in thermal contact with a component, is measured at a first thermal position by means of at least one first temperature sensor which is in thermal contact with the component or with the component part, and a second temperature of a component, or of a component part of a soldering or sintering device in thermal contact with a component, is contactlessly measured at a second thermal position by means of at least one second temperature sensor. Thereby the first thermal position and the second thermal position have a spatial distance, so that a temperature gradient between first temperature and second temperature is expectable during variation of temperature. The measured second temperature is calibrated on basis of the measured first temperature in order to determine a calibrated second temperature, wherein the heat source is controlled at least on the basis of the calibrated second temperature. The invention further relates to a corresponding soldering or sintering device.

Description

Methods for temperature regulation and welding or sintering apparatus for manufacturing components with welded or sintered joints.

The present invention relates to a method for temperature regulation of components for creating welded or sintered joints between such components, wherein at least one controllable heat source is provided for supplying heat energy to be transferred to the components.

Furthermore, the present invention relates to a welding or sintering apparatus for manufacturing welded or sintered joints between components, wherein the welding or sintering apparatus has at least one controllable heat source configured to supply heat energy to be transferred to the components.

When sintering and welding two or more components, especially electronic components and substrates, it is possible to connect them to each other electrically and/or thermally by means of a bonding material, wherein the bonding material is sintered or melted. Here, the components to be joined can be compressed between an upper tool and a lower tool, wherein, generally speaking, the pressure is substantially higher during sintering than during welding. In the case of known sintering or welding apparatus, the heat energy required for sintering or welding can be transferred to the components via the upper and lower tools.

Examples of familiar sintering or welding apparatus and corresponding methods are described in, for example, DE 10 2006 034 600 B4, DE 203 00 375 U1, DE 10 2004 047 359 B3, DE 10 2012 206 403 B3 and WO 2014/135151 A2.

An apparatus or facility for manufacturing welded or sintered joints may have one or more processing chambers in which a processing atmosphere required for performing the welding or sintering method may be set, and especially changed during the process. Components to be joined, previously assembled and which can be appropriately fixed relative to each other to maintain their desired position as needed, can be transported to, from, and between different processing chambers by suitable transport components. The processing atmosphere in each processing chamber may be set and/or changed, for example, relative to its material composition, its pressure, and/or its temperature. For example, different mixtures of processing gases may be used to set pressures between 1 hPa and 1200 hPa.

In conventional welding or sintering apparatus, heat energy can be input via upper and/or lower tools. As a general principle, indefinitely spaced heating plates or infrared radiators can also be used as heat sources. Another possibility for heating components is to input heat energy into the component or into a suitable carrier plate via induction. For this purpose, one or more induction devices can be arranged in processing chambers above and/or below the components to be connected. This creates corresponding induction zones designed so that electromagnetic energy generated by the induction devices is input into the component, and eddy currents are generated in the heated component at these locations. To cool the sensing devices, these devices can be directly connected to the coolant circuit through which the fluid flows, where cooling may also be achieved through thermal contact with the walls of the processing chamber. Cooling via convection is also possible.

As a general principle, given differences in component quality, the distance between the sensing device and the component or carrier plate can be varied to optimize heat or energy input. To this end, existing sensing devices can be upgraded or downsized, either jointly or individually. Furthermore, it is possible to adapt the shape of the sensing device to the shape of the component or carrier plate for optimal energy input.

Compared to component heating via thermal radiation or thermal contact, energy input via sensing is much easier to control. Using sensing devices, heat input can be uniformly controlled between zero power and maximum power in fractions of a second.

In order to fully utilize the heat source, whose thermal input can be adjusted in a highly dynamic manner, especially by using the aforementioned sensing devices to achieve precise and differentiated temperature control in both time and space, it is necessary to provide adaptive control of the heat source, taking into account the delays in heat transfer within the component. Accurate measurement of the component temperature is extremely important here.

As is known, component temperature is measured by one or more temperature sensors that are in thermal contact with the component; that is, the temperature sensors are in contact with the component being measured or integrated therein. If the location where heat energy is input into the component is a certain distance from the location where the temperature is measured, a time lag may occur between the energy input and the temperature measurement due to the limited thermal conductivity of the component. This may lead to inaccurate control of the component temperature and cause thermal overload of the component due to "overshoot".

To reduce the inaccuracy of this type, the temperature measurement location can be chosen to be as close as possible to the energy input location. Control of the heat source can then respond quickly to temperature changes; however, the actual temperature of the component cannot be measured very accurately because it does not experience heat energy directly, but rather indirectly through thermal coupling, and therefore has a time lag.

DE 10 2004 047 359 B3 proposes the use of non-contact optical measurement systems (such as thermometers) for temperature measurement. However, this type of optical measurement system has the disadvantage that the measured temperature is not absolute, but depends on the material properties and surface properties of the components.

DE 11 2008 000 853 T1 describes temperature measurement in a heat treatment chamber having heating elements, components, contact temperature sensors, and non-contact temperature sensors. The non-contact temperature sensors are located outside the heat treatment chamber, and the temperature orientations used to detect the temperatures of the contact and non-contact temperature sensors are nearly identical, such that the measurement difference of the non-contact temperature sensor can be eliminated by the measurement value of the contact temperature sensor. However, the dimensional stability and sensor mass are extremely low, resulting in measurement gaps where changes in the number of molecules can rapidly affect temperature changes.

The objective of this invention is to provide a method for temperature regulation of components for creating welded or sintered joints between components, which allows for precise setting of component temperature and flexible placement of temperature sensors.

This invention also aims to compensate for the interference effects of pressure/gas fluctuations caused by non-contact sensors.

The objective is achieved by a method having the features of technical solution 1. Advantageous developments of the method are indicated in the appendix.

A method for temperature regulation of a component is proposed for creating a welded or sintered joint between components, wherein at least one controllable heat source is provided to supply heat energy to be transferred to the component. A first temperature of the component or a portion of the component in thermal contact with the component, or the welding or sintering apparatus, is measured at a first hot location by means of at least one first temperature sensor in thermal contact with the component or the portion of the component, and a second temperature of the component or a portion of the component in thermal contact with the component, or the welding or sintering apparatus, is measured non-contactly at a second hot location by means of at least one second temperature sensor. The first and second hot locations are spatially separated such that the temperature gradient between the first and second temperatures is predictable during temperature changes. The second temperature is calibrated based on the first temperature measurement to determine the calibrated second temperature, wherein the heat source is controlled at least based on the calibrated second temperature. Measurements of the first and second temperatures are preferably performed at different locations. The component portion of the welding or sintering apparatus that is in thermal contact with the component and is referred to below simply as the apparatus component can be, for example, a carrier plate, carrier frame, or component carrier that supports the components to be connected during the manufacturing process. The first temperature can also be separately determined by a temperature sensor integrated into the component and connectable to a control unit designed to perform the method, so as to transmit the first temperature of the component to the control unit. Therefore, if the first temperature of a component or device is measured by a plurality of first temperature sensors, the first temperature can be determined in an appropriate manner, such as by averaging the temperatures measured by the plurality of first temperature sensors, or by other methods. The same applies to the second temperature.

The spatial distance between the first and second temperature sensors means their spatial distribution under any circumstances, that is, they can be placed on one side of the component, separated by a spatial distance, or placed on opposite sides of the component. For example, the first and second temperature sensors can be placed on the same side of the component with a distance of at least 5%, especially 10%, of the component's diameter. In any case, during the heating or cooling phase, it is expected that the first and second temperature sensors, which measure at different locations, will record measurements showing the temperature gradient. Under thermal equilibrium, that is, when the residence time at constant temperature conditions is longer, the temperature gradient may become smaller or disappear completely. However, if the heat input from the heat source changes at least during the heating or cooling phase, it is expected that the temperature sensors will record different measurements due to the different spatial distances between the first and second temperature sensors. Under no circumstances can it be assumed that the first temperature sensor records the same measurement as the second temperature sensor; this means that the second temperature sensor can be calibrated by the first temperature sensor as part of the temperature gradient, especially under dynamic temperature conditions. Advantageously, the spatial arrangement of temperature sensors allows for greater flexibility in placement. Therefore, preferably, a second temperature sensor on the heat-source-facing side of the component or component carrier, as a component in thermal contact with the component, can detect a second temperature for controlling the heat source. The first temperature sensor can be placed at an easily accessible point on the machinery of the component or component carrier to detect the first temperature. Thus, with this spatial arrangement, accurate calibration of the first temperature of the first temperature sensor to the second temperature of the second temperature sensor is possible even in confined spaces or inaccessible temperature locations. Furthermore, a temperature sensor already integrated into the component can also be used, for example, as the first temperature sensor.

In the method according to the invention, the first temperature and the second temperature are thus combined in a suitable manner to achieve optimal temperature control at the component. Preferably, the first temperature and the second temperature are measured in such a way that the temperature does not substantially change within a defined time period, thereby greatly reducing the effects of time lag during thermal equilibrium within the component or between the component and the device component it contacts. The first temperature and the second temperature may be measured at the same component or at the same device component, or at different components or device components, and in any case at two spatially distant thermal locations (i.e., thermal orientations).

In this context, calibration means, under specified conditions, the sum of activities used to determine the relationship between the measured value of the temperature variable (a temperature variable with correlated measurement uncertainty) output by the second temperature sensor and the measured value of the first sensor (as a reference temperature sensor with correlated measurement uncertainty). This correlation can be used to take into account the influence of the spatial distance between the first and second temperature orientations, as well as other differences caused by measurement techniques.

The determination of the calibrated second temperature specifically addresses the following fact: when using a non-contact operating temperature sensor, the measured second temperature will, under normal circumstances, differ from the actual temperature at the measurement point. This is due to the fact that non-contact temperature measurement may vary due to the material properties and/or surface properties of the component or device being measured.

According to a preferred embodiment, the method is performed in a settable treatment atmosphere, wherein setting the treatment atmosphere includes at least setting the material composition, pressure, and/or temperature of the treatment atmosphere. For example, depending on the specific stage of the process, the treatment atmosphere may contain reactive or non-reactive treatment gases. If the temperature of the treatment atmosphere changes, this temperature change can also be incorporated into the control of the heat source.

According to another preferred embodiment, the first temperature sensor is selected from the group comprising at least the following: NTC resistors, PTC resistors, semiconductor temperature sensors, thermocouples, and temperature sensors based on resonant circuits. Alternatively or additionally, the second temperature sensor is a sensor configured to detect thermal radiation, and is preferably selected from the group comprising at least the following: pyrometers, calorimeters, and thermopile. As an example, the sensor type mentioned for the first temperature sensor represents a typical example of a contact-based temperature sensor. Therefore, as an example, the sensor type mentioned for the second temperature sensor is a typical non-contact operating temperature sensor.

According to another preferred embodiment, at least one heat source is configured to perform contact-based or non-contact heat transfer to the component or to one or more of the mentioned component portions. The heat source is preferably selected from a group including electric, magnetic, or electromagnetic field generators, more preferably heating plates, inductive heating elements, or infrared radiators, which can be coupled to the component or to the mentioned component portions at least thermally, inductively, or capacitively. The list of possible heat sources is not conclusive. However, it becomes apparent that magnetic field generators (which may also be referred to as inductive devices or inductors) that can be inductively coupled to the component or to the mentioned component portions are particularly suitable. This type of sensing device can be used to control heat output in various ways, such as by changing the operating voltage, operating current, or frequency.

According to another preferred embodiment, the heat source is controlled in a process step involving the fabrication of welded or sintered joints, and a calibrated temperature is determined in at least one calibration step prior to the process step. This calibration step includes generating and storing individual calibration functions, based on which a calibrated second temperature is determined from a measured second temperature. For example, the calibration step may be performed by measuring a first temperature and a second temperature under two different component temperatures or component portion temperatures, so that a calibration function is then determined from the measured values. It is also possible to perform several calibration steps, in which several calibration functions are determined. For example, this can be achieved by generating and storing calibration functions specifically for each component or for a portion of a component.

According to a preferred embodiment, a calibration step is performed before each execution of a process step, where heat source control is performed in the process step based on a previously determined calibration function. To select a suitable calibration function, it is not necessary to know the properties of the component or device measuring the second temperature. Performing a calibration step before executing the process step ensures that temperature control will not damage components due to incorrect selection of the calibration function.

Alternatively or additionally, the calibration step may be performed one or more times during the process steps, preferably at a defined time point or at a time point where the temperature of the component or device component does not substantially change. The aforementioned calibration step at a time point where the temperature of the component or device component does not substantially change involves performing calibration when the temperature profile of the component or device component has a stable period at different temperatures under various conditions. This is to allow a defined equilibrium time to be reached in order to eliminate latency caused by differences in temperature measurement principles and the spatial location of the measurement points.

Relatedly, it has proven advantageous that, prior to the execution of a process step, the calibration function matched to the component to be processed is selected from a plurality of calibration functions stored in a component-specific or component-part-specific manner, wherein heat source control in the process step is performed based on the selected calibration function. As a general principle, a calibration function may also be selected initially, and then checked and/or adjusted during the execution of the process step.

According to another advantageous specific example, the calibration function is a linear function or a polynomial function, preferably a quartic function. The use of a linear function has proven to be easy to calculate, which allows for any inaccuracies that may occur here. Polynomial functions, especially quartic polynomial functions, are particularly suitable for calibrating the measurement characteristics of thermometers.

According to another advantageous specific example, a two-stage method is used to control a heat source. In the first stage, a modified setpoint temperature is determined based on a measured first temperature and a preset setpoint temperature. In the second stage, the output from the heat source is controlled based on a measured or calibrated second temperature and the modified setpoint temperature. This type of two-stage control is also called cascade control. The preset setpoint temperature does not necessarily have to be a fixed setpoint temperature; in practice, a curve or slope of the setpoint temperature can be used as a basis. Specifically, the statement "based on the measured first temperature, the preset setpoint temperature, the measured or calibrated second temperature, and the modified setpoint temperature" is not limited to the absolute values of these variables, but explicitly includes the individual curves of these variables over time, that is, especially the mathematical derivation of these variables relative to time. Furthermore, determining the modified setpoint temperature based on the measured first temperature and the preset setpoint temperature does not preclude the inclusion of other parameters or measured values in the determination of the modified setpoint temperature when necessary. Therefore, controlling the output of the heat source cannot be based solely on the measured or calibrated second temperature and the modified setpoint temperature. In fact, other parameters or measured values can also be included here. Specifically, in each stage of the two-stage approach, feedback can also be provided to the individual control loops.

According to another preferred embodiment of the method, the components to be connected are arranged in a main plane, wherein a first temperature sensor is arranged on one side of the main plane, and a heat source and a second temperature sensor are arranged on the other side of the main plane. Although the second temperature sensor and the heat source are arranged on the same side of the component arrangement, and therefore the temperature change of the component can be recorded in a very short time lag, the first temperature determined by the first temperature sensor is subject to a certain latency due to its spatial arrangement, and it is based on the heat conduction inside the component or device component.

Alternatively, the first and second temperature sensors may be arranged on one side of the main plane, and the heat source may be arranged on the other side of the main plane. Alternatively, the first and second temperature sensors and the heat source may be arranged on the same side of the main plane.

In another embodiment, the present invention relates to a welding or sintering apparatus for manufacturing welded or sintered joints between components, comprising: at least one controllable heat source configured to supply heat energy to be transferred to the components; at least one first temperature sensor at a first hot position, which is in thermal contact with the component or a component portion of the welding or sintering apparatus that is in thermal contact with the component, and configured to measure a first temperature of the component or the component portion; a second temperature sensor at a second hot position, configured to non-contactly measure a second temperature of the component or the component portion of the welding or sintering apparatus that is in thermal contact with the component; and a control unit connected to the heat source and to the first and second temperature sensors and configured to perform the method as described in any of the foregoing technical solutions. Therefore, the first and second heating locations are spatially separated, making the temperature gradient between the first and second temperatures predictable during temperature changes. As mentioned above, the first temperature sensor or another first temperature sensor can be a temperature sensor integrated into the component and connected to the control unit to transmit the first temperature of the component to the control unit.

According to a preferred embodiment, the heat source has a measurement window that allows infrared radiation emitted by the component or the aforementioned component portion of the welding or sintering apparatus to be transmitted in the direction of the second temperature sensor.

According to another preferred embodiment, at least a tube facing the direction of the second temperature sensor is arranged in the measurement window and configured to guide infrared radiation emitted by the component or by the aforementioned component portion of the welding or sintering apparatus in the direction of the second temperature sensor, and preferably shield the second temperature sensor from infrared radiation not emitted by the component or the aforementioned component portion.

According to another preferred embodiment of the welding or sintering apparatus, a component, at least one heat source, at least a first temperature sensor, and at least a second temperature sensor are disposed in or on an airtight processing chamber having an adjustable processing atmosphere, particularly a vacuum. Preferably, the second temperature sensor is disposed on the side of the heat source opposite to the component. In other words, the welding or sintering apparatus may include at least one airtight processing chamber in which a processing atmosphere, such as a low-oxygen or oxygen-free atmosphere, particularly a vacuum, can be provided, allowing the component to be heat-treated, particularly welded or sintered, without oxidation. Both the first and second temperature sensors are disposed in or on the processing chamber such that measurement signals from the temperature sensors are transmitted to the outside of the processing chamber as the first and second temperatures. The second temperature sensor can be placed inside or outside the processing chamber; in the latter case, the second temperature sensor can observe the second temperature orientation through an optical window in the processing chamber wall. A control unit preferably located outside the processing chamber calibrates the second temperature based on the first temperature and controls the heat source based on the calibrated second temperature. In this way, precise heat source control can be achieved, and this heat source control can also be used, for example, to maintain a definable temperature gradient between the first and second temperature orientations.

Figure 1 shows a schematic and simplified cross-sectional view of a welding apparatus 10 according to an example. The welding apparatus 10 includes a dish-like transport frame 14 with an open bottom. A component carrier 12 is placed in an opening on the bottom side of the transport frame, representing a component portion of the welding apparatus 10. Components 16 and 18 to be connected are placed on the component carrier 12. Components 18 may be, for example, substrates that are each connected to several components 16 (e.g., power semiconductors) by welding operations. Connecting materials (not shown) may be disposed between components 16 and 18 respectively. Below the transport frame 14 in which the component carrier 12 is disposed, a sensing device 20 configured to generate a strong magnetic field that can induce eddy currents at least in the component carrier 12 is disposed. These eddy currents affect the heating of the component carrier 12. Needless to say, other heat sources other than the sensing device 20 can also be provided. The distance between the component carrier 12 or the conveyor frame 14 on one side and the sensing device 20 is variable.

The welding apparatus 10 further includes a first temperature sensor 24 at a first temperature position, which is located on the upper side of the substrate that serves as component 18. The first temperature sensor passes through the conveyor frame 14 and is in spring-loaded contact with one of the components 18 and is configured to measure the first temperature.

The sensing device 20 has a measurement window 22 that allows infrared radiation emitted from the bottom side of the component carrier 12 (as a second hot position) to be transmitted in the direction of a second temperature sensor 26 disposed below the measurement window 22, thereby allowing the measurement of a second temperature by means of the second temperature sensor 26. In this specific embodiment, the first temperature orientation and the second temperature orientation are disposed on opposite sides of the component carrier 12.

Preferably, the first temperature orientation may be the surface of component 18. Preferably, the second temperature orientation may be the surface of component 18 or the surface of heat source 20 on the underside of component 18 or component carrier 12, where direct or indirect heat input (e.g., IR radiant heat) occurs.

The first temperature sensor 24 is designed as a contact temperature sensor and may be an NTC resistor, a PTC resistor, a semiconductor temperature sensor, a thermocouple, a temperature sensor based on a resonant circuit, or the like. The second temperature sensor 26 is a non-contact temperature sensor, such as a pyrometer, radiometer, or thermopile, which measures temperature by detecting infrared radiation emitted by the object being measured.

According to the modification (not shown), the tube can be placed in a certain area of the measurement window 22, which also surrounds the second temperature sensor 26, and on the one hand, concentrates or guides the infrared radiation emitted by the component carrier 12 and to be detected, while keeping external radiation that may tamper with the temperature measurement away from the second temperature sensor 26.

Figure 2 illustrates a welding apparatus 110 according to another embodiment, which is designed similarly to the welding apparatus 10 from Figure 1. The welding apparatus 110 includes several component carriers 12, three in this embodiment, each with an individually controllable sensing device 20 associated with a component carrier 12. The distance between the sensing device 20 and the component carrier 12 is individually adjustable. All three component carriers 12 are arranged on a common conveyor frame 14. Associated temperature sensors 24 and 26 are arranged similarly to the example from Figure 1.

The components of the welding apparatus 110 are located in a processing chamber 28, which provides a preferably settable processing atmosphere for the welding process. The processing chamber 28 can be temperature-regulated, evacuated, and/or pressurized, or filled with different processing gases. The pressure and/or temperature of this processing atmosphere can be set to preset values and, in particular, can be changed. A first temperature sensor 24 and a second temperature sensor 26 are disposed in or above the processing chamber 28. Specifically, the second temperature sensor 28 is disposed outside the processing chamber and measures a second temperature point through an optical window in the processing chamber wall.

Figure 3 illustrates a welding apparatus 210 according to another embodiment, which in principle represents the reverse of the welding apparatus 110 of Figure 2 on the horizontal axis. Unlike the embodiments in Figures 1 and 2, the first temperature sensor 24 does not have thermal contact with component 18, but rather with the bottom side of component carrier 12, which serves as the first hot position. The second temperature sensor 26, instead of measuring the temperature of component carrier 12, can directly record the temperature of components 16 and/or 18 disposed above component carrier 12 at the second hot position.

All three examples demonstrate apparatuses configured to perform the method according to the invention, as welding apparatuses 10, 110, and 210. It goes without saying that the arrangement of temperature sensors 24 and 26 described herein can also be provided as examples, alternatively for corresponding sintering apparatuses. Using this type of sintering apparatus, additional tools are provided as is customary to apply pressure to the components to be joined in order to manufacture the sintering apparatus. These tools may have suitable measuring openings, through which access is provided for non-contact or contact-based temperature measurement required for temperature measurement at the components or component portions of the sintering apparatus.

It goes without saying that welding devices 10, 110, and 210 may also have the necessary tools that might be required to apply pressure to components 16 and 18. For clarity, these are not shown in this embodiment of the invention.

A method for temperature regulation of components according to the present invention is now described in a simplified manner to create a welded or sintered joint between components 16 and 18. This method can be performed using welding devices 10, 110, and 210 according to Figures 1 to 3, for example, in a control unit (not shown) connected to temperature sensors 24 and 26 and to sensing device 20, which serves as a heat source. With this type of control unit, it is particularly possible to control the heat output generated by heat source 20 to heat components 16 and 18 to the desired temperature and to cool them again by reducing or cutting off the heat output.

While the first temperature sensor 24 can determine the component temperature or component portion temperature at the first hot location with high accuracy due to its contact-based operating mode, the component temperature or component portion temperature at the second hot location determined by the second non-contact operating temperature sensor 26 is subject to systematic measurement errors. An example of this type of non-contact operating temperature sensor is a thermometer. This determination is based on the radiant power P emitted by the measuring body, the temperature of which is to be determined. For technical reasons, only the defined wavelength range within the infrared range is considered here as a general rule. According to the Stefan-Boltzmann law, the following applies to the total radiant power P of a real subject: P = ε · σ · A · T4, (1) where ε is the emissivity, σ is the Stefan-Boltzmann constant (σ = 5.6704 · 10 ^-8 Wm ^-2 K ^-4 ), A is the area (in m²) and T is the temperature (in K). The emissivity ε thus represents the thermal radiation capacity of the measured object and depends on both the material and surface quality of the measured object. The second temperature is preferably determined using a small wavelength. The measurement wavelength of the pyrometer is preferably no more than 5 µm, and especially preferably no more than 2 µm, in order to limit the influence of the undetermined emissivity ε on the measurement accuracy.

Since the emissivity ε of the measured object (i.e., the component or the component portion of the welding or sintering apparatus) is usually not precisely known or is subject to local variations, the measured second temperature may have systematic measurement errors. For this reason, a calibrated second temperature is determined based on the measured second temperature, wherein the measured first temperature is used as a calibration variable. Here, in order to exclude the difference between the actual temperature at the first hot position where the first temperature is measured and the actual temperature at the second hot position where the second temperature is measured, the temperatures of the components 16, 18 or the component portions of the welding apparatus 10, 110, 210 that are in thermal contact with the components should be as balanced as possible, that is, there should be no further temperature gradient between the different locations where the first hot position and the second hot position are measured. For example, this can be achieved by keeping the heat output of the heat source constant for a certain equilibrium time, or by adjusting it to a constant temperature, and only then can the corresponding measured temperature value be determined.

The second temperature can be determined, for example, based on a calibration function that is determined as part of the calibration process. The determination of such a calibration function is described in more detail below.

An advantage of the method according to the present invention is that the measurement of the first temperature at the first hot location using a temperature sensor in thermal contact with the component or device component (and therefore slower but delivering highly accurate measurements) is appropriately combined with the measurement of the second temperature at the second hot location using a non-contact operating temperature sensor (and therefore faster but delivering less accurate measurements due to its material dependence). Optimal temperature control at the component is achieved through this combination of the first and second temperature measurements. Furthermore, flexible and spaced arrangement of the first and second temperature sensors is possible.

Figure 4 shows illustrative curves of the first temperature (T1) and the second temperature (T2) over time, where the absolute values of the time scales are arbitrary. Temperatures T1 and T2 are measured on opposite sides of a component made of copper with a thickness of 5 mm. The heat source 20 is located on the same side as the temperature sensor 26 that records the second temperature T2, while the temperature sensor 24 that records the first temperature T1 is located on the side of the component opposite to the heat source 20 (see the arrangement in Figures 1 and 2).

Although the second temperature T2 reaches its maximum value at approximately t=48 seconds, the first temperature T1 reaches a plateau at approximately t=55 seconds, meaning that the first temperature T1 remains roughly constant thereafter. The 7-second time difference between the second temperature T2 reaching its maximum value and the first temperature T1 reaching its plateau is based on the latency of heat transfer between the two sides of the component.

Furthermore, as can be seen in Figure 4, the curve for the first temperature T1 is substantially slower than that for the second temperature T2, thus exhibiting reduced fluctuations. Additionally, since calibration has not yet been performed, there is a temperature difference of approximately 20°C to 25°C between the two temperatures T1 and T2 (Figure 4 shows the measured second temperature T2).

Referring to Figure 5, the calibration procedure will now be explained below as an example. For this purpose, at a first time point t1, at an exemplary component where the temperature continuously or intermittently increases, a first temperature T1.1 is measured in contact and a second temperature T2.1 is measured non-contactly. At a second time point t2, the first temperature T1.2 and the second temperature T2.2 are now measured.

Under the simplified assumption of a linear correlation between the measured second temperature T2 and the calibrated second temperature T2', the calibrated second temperature T2' can be determined according to the following equation: T2' = k*T2 + T _offset , (2) where k is the calibration factor and T _offset is the temperature difference at time point t1. The factor k can be determined according to the following equation based on the temperatures measured at time points t1 and t2: k = (3)

The temperature difference T _offset can be determined by measuring the temperature value according to the following equation: T _offset = T1.1 - (T2.1*k). (4)

The temperature measurements used to determine the calibration function are advantageously performed at time points when the component does not have a temperature gradient; that is, the component temperature remains constant for an appropriate duration under all conditions, such as 5 seconds in a stable phase, during which the component temperature must, of course, change between two time points t1 and t2. It is also possible, according to general principles, to perform calibration again at preset time points, for example, at 10-second intervals.

Alternatively, the calibration step can also be performed as part of a sample calibration step, which is performed on a sample component whose emission attributes are matched with the emission attributes of components processed later or device components in contact with the sample component, in order to preserve the calibration function. During the actual process steps, that is, during the actual welding or sintering operations, this calibration function can be relied upon later without the need to perform new calibrations during the process steps.

Instead of the calibration explained in Figure 5, the emissivity ε can also be determined directly. This can be achieved, for example, by first determining the first temperature T1.1 in contact and the second temperature T2.1 in non-contact at an ambient temperature of, for example, 20°C, similar to the description in Figure 5. The component used as the test object is then heated to a higher temperature, for example, between 150°C and 250°C, and the first temperature T1.2 and the second temperature T2.2 are determined again.

The emission rate ε can then be calculated using the following equation: ε = (5)

This place assumes Xiaoyu Otherwise, these values must be changed so that the emission rate ε ≤ 1.

Referring to Figure 6, a two-stage or cascade control of a heat source is now described, where the control variable for this heat source is described by a function u2(t). Two temperature sensors are placed on the object being measured, where the first temperature sensor in contact with the object generates a first temperature T1, and the non-contact temperature sensor generates a second temperature T2. The curve of the first temperature T1 is described by a function yM1(t), and the curve of the second temperature T2 is described by a function yM2(t). The setpoint temperature function w1(t) serves as the input variable for control.

From the signals w1(t) and yM1(1), the difference function e1(1) is generated by obtaining the difference according to the following equation. (6) And it is transmitted to the main controller R1. The main controller R1 can be designed, for example, as a PI (proportional-integral) controller, which generates the control function u1(t) according to the following equation. (7) Where kp and ki are expansion factors respectively. By positive coupling with the setpoint temperature function w1(t), the modified setpoint temperature function w2(t) is determined from u1(t) according to the following equation. (8)

In the second control stage, the difference between the modified setpoint temperature function w2(t) and the function yM2(t) is formed according to the following equation: (9) This is to generate the input function e2(t) for the slave controller R2. The slave controller R2 then generates the control variable or control function u2(t) for the heat source according to the following equation. , (10) where kp and ki are expansion factors respectively.

It goes without saying that the specific implementation of cascading control is presented here purely as an example and can be modified in a suitable manner if necessary.

The output from the heat source is set in an appropriate manner. Therefore, for example, when using the sensing device 20 according to Figures 1 to 3 as a heat source, it is possible to control it by means of the control unit of the sensing device 20 and by adjusting the frequency, current and/or voltage. In addition, the distance of the sensing device 20 can also be incorporated into the control.

When using an infrared heater or an ohmic heating device, the heating current can be adjusted.

Because the heat source or components 16, 18 or component carrier 12 react quickly to the side facing the sensing device 20, the temperature curve on the component side facing the sensing device 20 can be controlled according to a generalized function (e.g., ramp, S-curve, quadratic function, e-function, phase-holding or higher-order polynomial).

This behavior can be used to accelerate the heating of components 16 and 18. To this end, the temperature of the component side facing the sensing device 20 can be temporarily increased to increase the temperature difference between the two opposite sides of components 16 and 18.

Because of variations in component quality, particularly on the side facing the sensing device 20, the second temperature sensor 26, which measures the temperature non-contactly, cannot record absolutely accurate temperatures. This deficiency is compensated for by measuring the side of the component facing away from the sensing device 20 using the first temperature sensor 24, as the temperature level is continuously adjusted from this value, ensuring that the desired temperature can always be set at components 16 and 18.

In some cases, the influence on contact with the first temperature sensor 24 may be caused by external influences, such as gas flowing into the processing chamber 28, thereby weakening control operation. This can be addressed by modifying the cascade control described in conjunction with Figure 6. Here, the control variable u1(t) generated by the master controller R1 can be "frozen" at a given time point, such as the time of a given gas input, with an appropriate value _u1freeze , thereby allowing for improved temperature control. Therefore, the modified setpoint temperature w2(t) is not based on u1(t) and the setpoint temperature w1(t), but rather on _u1freeze and w1(t).

Now refer to Figures 7 and 8 to describe typical curves of functions w1(t), yM1(t), yM2(t), and u2(t) over time, where characteristic event points are identified by numbers in the graphs.

As can be seen in Figure 7, at event points 1 and 3, a drop in the first temperature T1 occurs, for example, by allowing gas to flow into the processing chamber. In the absence of the aforementioned "freeze function" in the cascade control, such a temperature drop will cause an overreaction of the cascade control, which can be clearly seen in the temperature peaks of the curves for the second temperature T2 at event points 2 and 4.

Improved temperature control of the component temperature can be achieved by "freezing" the control variable u1(t) generated by the main controller to the value _u1freeze before an event that could cause a short-term change in component temperature begins.

Referring to Figure 8, the characteristic events and operations (also identified by numbers) during the execution of the method according to the present invention by means of the aforementioned cascade control will now be explained. The segment of the second temperature T2 curve (yM2(t)) numbered 1 defines the characteristic of the lower limit of the measurement range of the thermometer. During this period, the control variable u2(t) has a constant curve, as indicated by number 2.

Control begins at event point 3. At event point 4, there is a strong overshoot at the second temperature T2; however, this does not cause an overshoot in the temperature curve (yM1(t)), see number 7.

Number 5 defines the characteristics of the difference between uncalibrated second temperatures T2, which are higher than the setpoint temperature identified by the function w1(t) due to the different surface properties of the measured object or component.

At event point 6, the first temperature T1 accurately reaches the predetermined setpoint temperature, wherein the measurement error of the non-contact measurement second temperature sensor 28 is compensated by the calibration described above.

1: Number 2: Number 3: Event Point 4: Event Point 5: Number 6: Event Point 7: Number 10: Welding Device 12: Component Carrier/Component Part 14: Conveyor Frame 16: Component 18: Component 20: Sensing Device/Heat Source 22: Measurement Window 24: First Temperature Sensor 26: Second Temperature Sensor 28: Processing Chamber 110: Welding Device 210: Welding Device k: Calibration Factor t1: First Time Point t2: Second Time Point T1: First Temperature T1.1: First Temperature T1.2: First Temperature T2: Second Temperature T2.1: Second Temperature T2.2: Second Temperature T _offset : Temperature Difference R1: Master Controller R2: Slave Controller

Further advantages are evident from the following diagrammatic description. The diagrams illustrate examples of the invention. The diagrams, description, and scope of the patent application contain numerous features in combination. Those skilled in the art will also readily consider these features individually and combine them into other meaningful combinations. In the figures: [Figure 1] shows a schematic cross-sectional view of a welding or sintering apparatus according to one example; [Figure 2] and [Figure 3] show schematic cross-sectional views of welding or sintering facilities according to another example; [Figure 4] shows a diagram of two illustrative temperature curves with a first temperature and a second temperature; [Figure 5] shows a schematic diagram explaining the calibration function for the second temperature; [Figure 6] shows a schematic block diagram of two-stage temperature control; [Figure 7] shows a diagram with various illustrative temperature curves and curves with relative heat output; and [Figure 8] shows a diagram with other illustrative temperature curves and curves with relative heating output.

The same element symbol is used below for the same or similar elements.

10: Welding Equipment

12: Component carrier/component part

14: Conveyor Frame

16: Components

18: Components

20: Sensing Device/Heat Source

22: Measurement Window

24: First Temperature Sensor

26: Second Temperature Sensor

Claims (16)

A method for temperature regulation of components (16, 18) for creating welded or sintered joints between the components (16, 18), wherein at least one controllable heat source (20) is provided to supply heat energy to be transferred to the components (16, 18), wherein the temperature of the components (16, 18) or the welding or sintering apparatus (10, 110, 210) at a first hot location is measured by means of at least one first temperature sensor (24). (16, 18) The first temperature (T1) of the component portion (12) in thermal contact, wherein at least one first temperature sensor is in thermal contact with the component (16, 18) or the component portion (12), and the component (16, 18) or the component portion (12) in thermal contact with the component (16, 18) is measured non-contactly at a second hot position by means of at least one second temperature sensor (26). The second temperature (T2) of the first heat source (T1) and the second heat source (T2) are spatially separated, such that the temperature gradient between the first temperature and the second temperature (T1, T2) is predictable during temperature changes, and the measured second temperature (T2) is calibrated based on the measured first temperature (T1) to determine the calibrated second temperature, and the heat source (20) is based at least on the measured second temperature (T2) or The control is achieved by adjusting the second temperature, wherein the heat source (20) is controlled in a two-stage method as a cascade control, wherein the modified setpoint temperature (w2) is determined in the first stage based on the measured first temperature (T1) and the preset setpoint temperature (w1), and wherein the output from the heat source (20) is controlled in the second stage based on the measured temperature (T1) or the adjusted second temperature and the modified setpoint temperature (w2). The method of claim 1, wherein the method is performed in a configurable treatment atmosphere, wherein setting the treatment atmosphere includes at least setting the material composition, pressure and/or temperature of the treatment atmosphere. The method of claim 1 or 2, wherein the first temperature sensor (24) is selected from the group consisting of at least the following: NTC resistor, PTC resistor, semiconductor temperature sensor, thermocouple and temperature sensor based on resonant circuit, and/or the second temperature sensor (26) is a sensor configured to detect thermal radiation, and preferably selected from the group consisting of at least the following: pyrometer, calorimeter and thermopile. The method of claim 1 or 2, wherein the at least one heat source (20) is configured to perform contact-based or non-contact heat transfer to one or more of the components (16, 18) or the mentioned component portions (12), and is preferably selected from the group comprising: electric field, magnetic field or electromagnetic field generator, preferably a heating plate, inductive heating element or infrared radiator, which may be coupled to the components (16, 18) or the mentioned component portions (12) at least thermally, inductively or capacitively. The method of claim 1 or 2, wherein the heat source (20) is controlled in a process step including the manufacture of the weld or sintered joint, and the calibrated temperature is determined in at least one calibration step prior to the process step, wherein the calibration step includes generating and storing respective calibration functions, based on which the calibrated second temperature (T2) can be determined from the measured second temperature. The method of claim 5, wherein the calibration step is performed before each execution of a process step, wherein the control of the heat source (20) is performed in the process step based on the previously determined calibration function. The method of claim 5, wherein the calibration step is performed one or more additional times during the process step, preferably at a defined time point or at a time point when the temperature of these components (16, 18) does not substantially change. The method of claim 5, wherein, prior to the execution of a process step, the calibration function matched with the components (16, 18) to be processed is selected from a plurality of calibration functions stored in a component-specific or component-part-specific manner, wherein control of the heat source (20) in the process step is performed based on the selected calibration function. As in the method of Request 5, the calibration function is a linear function or a polynomial function, preferably a quartic function. The method of claim 1 or 2, wherein in the first stage, the master controller (R1) determines the modified setpoint temperature (w2) based on the measured first temperature (T1) and the preset setpoint temperature (w1), and in the second stage, the slave controller (R2) determines the output of the heat source (20) based on the modified setpoint temperature (w2) and the measured second temperature (T2) or the calibrated second temperature. The method of claim 10, wherein the master controller (R1) is a PI controller. The method of claim 1 or 2, wherein the components (16, 18) to be connected are arranged in a main plane, wherein the first temperature sensor (24) is arranged on one side of the main plane and the heat source (20) and the second temperature sensor (26) are arranged on the other side of the main plane, or wherein the first temperature sensor and the second temperature sensor (24, 26) are arranged on one side of the main plane and the heat source (20) is arranged on the other side of the main plane, or wherein the first temperature sensor and the second temperature sensor (24, 26) and the heat source (20) are arranged on the same side of the main plane. A welding or sintering apparatus (10, 110, 210) for manufacturing welded or sintered joints between components (16, 18) comprises: at least one controllable heat source (20) configured to supply heat energy to be transferred to the components (16, 18); at least one first temperature sensor (24) at a first hot position, which is in thermal contact with the components (16, 18) or a component portion (12) of the welding or sintering apparatus (10, 110, 210) that is in thermal contact with the components (16, 18), and configured to measure a first temperature (T1) of the components (16, 18) or the aforementioned component portion (12); and a second hot position. A second temperature sensor (26) at a location configured to non-contactly measure the second temperature (T2) of a component portion (12) of the component (16, 18) or the welding or sintering apparatus (10, 110, 210) that is in thermal contact with the component (16, 18); the first hot location and the second hot location are spatially separated such that the temperature gradient (T1, T2) between the first temperature and the second temperature is predictable during temperature changes; and a control unit connected to the heat source (20) and to the first temperature sensor and the second temperature sensor (24, 26) and configured to perform the method as claimed in any of claims 1 to 12. The welding or sintering apparatus (10, 110, 210) of claim 13, wherein the heat source (20) has a measuring window (22) that allows infrared radiation emitted by the components (16, 18) or by the component part (12) mentioned in the welding or sintering apparatus (10, 110, 210) to be transmitted in the direction of the second temperature sensor (26). The welding or sintering apparatus (10, 110, 210) of claim 14, wherein at least the tube facing the direction of the second temperature sensor (26) is arranged in the measuring window and configured to guide infrared radiation emitted by these components (16, 18) or by the component portion (12) mentioned in the welding or sintering apparatus (10, 110, 210) in the direction of the second temperature sensor (26), and preferably shield the second temperature sensor (26) from infrared radiation not emitted by these components (16, 18) or by the component portion (12) mentioned in the welding or sintering apparatus (10, 110, 210). The welding or sintering apparatus (10, 110, 210) of any of claims 13 to 15, wherein the components (16, 18), the at least one heat source (20), the at least first temperature sensor (24) and the at least second temperature sensor (26) are disposed in or on an airtight treatment chamber (28) having an adjustable treatment atmosphere, particularly a vacuum, wherein the second temperature sensor (24) is preferably disposed on the side of the heat source (20) opposite to the components (16, 18).