EP3815801B1 - Method for cleaning a surface and vacuum connection method, and retrofitting set for a surface cleaning device, surface cleaning device, and vacuum connecting device comprising a surface cleaning device - Google Patents

Description

The invention relates to a cleaning method for cleaning a surface, in which the surface is cleaned with a process gas, wherein a feed gas containing the process gas is directed to the surface. Furthermore, the invention relates to a vacuum joining method for firmly joining two surfaces to one another, in which at least one of the surfaces to be joined is first cleaned and then joined to the other surface. Furthermore, the invention relates to a retrofit kit for a surface cleaning device for cleaning surfaces with a process gas. Furthermore, the invention relates to a surface cleaning device for cleaning a surface with a process gas, comprising a cleaning chamber for accommodating an element whose surface is to be cleaned. Finally, the invention relates to a vacuum joining device for firmly joining two surfaces to one another in a vacuum, comprising a surface cleaning device. Firmly joining surfaces in a vacuum chamber is generally known. In particular, metallic surfaces are soldered together in a vacuum or firmly joined by sintering. Before or even during the joining of the surfaces, the process gas is used to clean the surfaces of contaminants, in particular oxide layers. However, the concentration of the process gas in a feed gas, which can be a carrier gas, such as an inert gas such as nitrogen, and other parameters, such as the temperature of the surface to be cleaned, influence the cleaning process. For example, these parameters can influence the cleaning progress, i.e. the speed at which the contamination is removed from the surface. If the concentration is too low or the temperature too low, cleaning takes longer than planned, thus reducing the cost-effectiveness of the cleaning process. However, if the concentration of the process gas is too high, undesirable effects can occur. For example, salts can form on the surface, which hinder the bonding process. Cleaning processes and devices for surfaces are described, for example, in EP 3 006 602 A1 and DE 10 2004 061 269 A1 revealed.

The above-mentioned parameters, concentration and temperature, are just a few of a multitude of parameters that influence cleaning and must be considered when evaluating the cleaning process. The evaluation of the cleaning process or procedure is therefore complex.

The invention is therefore based on the object of providing a cleaning method that enables simple and efficient assessment of the cleaning. Furthermore, the invention is based on the object of providing a vacuum connection method that can be carried out simply and efficiently. In addition, the invention is based on the object of providing a retrofit kit for a surface cleaning device that makes it possible to retrofit an existing surface cleaning device in such a way that cleaning carried out with the surface cleaning device can be assessed simply and efficiently. Furthermore, the invention is based on the object of providing a surface cleaning device with which it is possible to assess surface cleaning carried out with the surface cleaning device simply and efficiently. Finally, the invention is based on the object of providing a vacuum connection device with which vacuum connections can be produced simply and efficiently.

For the cleaning method mentioned above, the problem is solved according to claim 1. For the vacuum connection method mentioned above, the problem is solved in that the cleaning method according to the invention is carried out to clean at least one of the surfaces to be connected. For the retrofit kit mentioned above, the problem is solved according to claim 7. For the surface cleaning device mentioned above, the problem is solved in that the surface cleaning device has the retrofit kit according to the invention. Finally, for the vacuum connection device mentioned above, the problem is solved in that the surface cleaning device is the surface cleaning device according to the invention.

The comparison of the proportion of process gas in the feed gas with the proportion of process gas and/or the proportion of reaction products in the exhaust gas therefore uses only two parameters to evaluate the cleaning, which is particularly simple and efficient and can be achieved, for example, with only two sensors.

The solution according to the invention can be further improved by various embodiments, each of which is advantageous in itself and, unless otherwise stated, can be combined with one another in any desired way. These embodiments and their associated advantages are discussed below.

According to one possible embodiment, the proportion of process gas and/or the proportion of reaction products in the exhaust gas is measured as the composition of the components of the exhaust gas. The proportion of process gas and the proportion of reaction products in the exhaust gas can be determined as the concentration of the process gas or the reaction products in the exhaust gas. By comparing the concentration of the process gas and/or the reaction products in the exhaust gas with the concentration of the process gas in the feed gas, the consumption of process gas by the cleaning process can be determined. An advantage of this embodiment can be that the cleaning process can be evaluated based on just one parameter, namely consumption.

According to one possible embodiment, the ratio of the process gas in the feed gas to the concentration of the process gas and/or the reaction products in the exhaust gas is formed to evaluate the cleaning process. An advantage of this An embodiment may be that the cleaning process can be evaluated based on only one parameter, namely the ratio.

According to one possible embodiment, cleaning process parameters are changed if the current cleaning progress is not within an expected range. For example, the temperature of the surface to be cleaned or the concentration of the process gas in the feed gas can be changed during cleaning. For example, additional process gas can be added or the gas already supplied can be removed as exhaust gas and feed gas with a changed process gas concentration can be fed to the surface again. Alternatively or additionally, the cleaning time, i.e. the time during which the process gas is in contact with the surface, can be changed, i.e., extended or shortened. An advantage of this embodiment can be that the cleaning process can be optimally controlled with little measurement effort based on a small number of evaluation parameters or even just one evaluation parameter.

According to one possible embodiment, the exhaust gas is directed away from the surface if a comparison of the concentration of the process gas in the feed gas with the composition of at least the components of the exhaust gas shows that the purification corresponds to a predetermined minimum purification level. An advantage of this embodiment may be that the duration of the purification is optimized and undesirable effects, such as salt formation, are avoided.

According to one possible embodiment, the process gas is methane or hydrogen gas. An advantage of this embodiment may be that such process gases can be easily measured in the feed gas or in the exhaust gas. Furthermore, their reaction products can also be easily measured in the exhaust gas.

According to one possible embodiment, the two surfaces to be joined are soldered together or firmly bonded by sintering. An advantage of this embodiment may be that vacuum joining processes, such as vacuum soldering and sintering, can be readily followed by the cleaning process according to the invention if the cleaning process according to the invention uses vacuum to keep atmospheric oxygen away from the surfaces to be cleaned and optionally also from the cleaned surfaces. Vacuum joining processes can be carried out in a cleaning chamber in which the cleaning process was carried out or in a vacuum joining chamber adjoining the cleaning chamber, whereby the chambers can be connected to one another in a vacuum-maintaining manner, for example by means of a vacuum lock.

According to one possible embodiment, the cleaning evaluation device has at least one signal output, and the cleaning evaluation device is configured to output control signals for controlling cleaning process parameters of the surface cleaning via the signal output. An advantage of this embodiment may be that the parameters of the cleaning method can be automatically controlled based on the at least one evaluation parameter.

According to one possible embodiment, the cleaning evaluation device is configured to output a cleaning end signal when the comparison of the concentration of the process gas in the feed gas with the composition of at least the components of the exhaust gas shows that the cleaning corresponds to a predetermined minimum cleaning level. An advantage of this embodiment may be that the duration of cleaning is optimized and undesirable effects, such as salt formation, are avoided. This can even be done automatically.

According to one possible embodiment, the vacuum joining device comprises the surface cleaning device or is connected to it, maintaining a vacuum. An advantage of this embodiment may be that the joining process can be carried out without intermediate storage of the cleaned elements to be joined. Intermediate storage of cleaned elements carries the significant risk of exposing the cleaned surface to oxygen, which may necessitate recleaning.

According to one possible embodiment, the vacuum joining device is a vacuum brazing or vacuum sintering device. Vacuum sintering devices can also be referred to as vacuum sintering systems.

An advantage of this embodiment may be that, in particular, vacuum soldering or vacuum sintering systems can be easily connected to the surface cleaning device according to the invention if the surface cleaning device according to the invention uses a vacuum to keep atmospheric oxygen away from the surfaces to be cleaned and, optionally, also from the cleaned surfaces. The surface cleaning device according to the invention can even be integrated into the vacuum connection device or be connected upstream of it. The surface cleaning device can be a cleaning chamber in which the cleaning process is carried out or in a vacuum connection chamber adjoining the cleaning chamber. The chambers can be connected to one another to maintain a vacuum, for example, by a vacuum lock.

According to one possible embodiment, the surface cleaning device is arranged upstream of the vacuum connection device along a processing path of the vacuum connection device or is integrated into the vacuum connection device. An advantage of this embodiment may be that the vacuum connection device can be easily constructed with the surface cleaning device as a production line or in a production line, or even integrated with each other.

According to one possible embodiment, the retrofit kit is designed to carry out the cleaning method according to the invention. In particular, the sensor devices can be designed to measure the concentration of the process gas in a feed gas and the composition of at least parts of an exhaust gas containing reaction products of the cleaning process, if the sensor devices for the feed and exhaust gas are conductively connected to the surface cleaning device.

The cleaning evaluation device can be designed to carry out the cleaning method to evaluate the current cleaning progress of the surface based on a comparison of the concentration of the process gas in the feed gas with the composition of at least the parts of the exhaust gas, in particular when the sensor signal inputs are connected to the sensor devices in a signal-receiving manner.

According to one possible embodiment, the surface to be cleaned has a metal oxide layer that covers an underlying metal. The cleaned metal surface is to be connected and, for example, soldered or sintered. At least the cleaned surface of the element therefore has a solderable or sinterable metal, for example, copper, nickel, or another solderable or sinterable metal. If the surface to be soldered is coated with solder, for example, tinned, the solder can be cleaned of a metal oxide layer, such as tin oxide.

• ab einer Prozesstemperatur von beispielsweise 150°C:
  
          MeO + HCOOH -> Me(COOH)₂ + H₂O
  
  
• ab einer Prozesstemperatur von beispielsweise 250°C:
  
          Me(COOH)₂ -> Me + CO₂ + H₂
  
          MeO + H₂ -> Me + H₂O
  
  

According to a possible embodiment in which the process gas is methane (HCOOH or CH ₂ O ₂ ) or hydrogen (H ₂ ), the cleaning reaction can proceed as follows (MeO = metal oxide, for example copper or nickel oxide):

• from a process temperature of, for example, 150°C:
  
  MeO + HCOOH -> Me(COOH) ₂ + H ₂ O
  
  
• from a process temperature of, for example, 250°C:
  
  Me(COOH) ₂ -> Me + CO ₂ + H ₂
  
  MeO + _H2 -> Me + _H2O
  
  

Carbon dioxide (CO2) and/or water (H2O) can be considered as reaction products.

The feed gas can be directed to the surface and remain there to clean the surface. If the process gas needs to be removed, for example because the surface has been sufficiently cleaned and/or to avoid undesired effects, the process gas can be removed together with the reaction products and the carrier gas, for example by suction or flushing. The concentration of the process gas in the feed gas can be determined during the feed to the surface and/or subsequently. The composition of at least the components of the exhaust gas can be determined during cleaning. The components can be the unreacted process gas and/or reaction products of the cleaning. The components can be determined as a concentration in the exhaust gas. The concentration of the process gas in the feed gas can be compared with the concentration of the components in the exhaust gas and, for example, put into relation to assess the cleaning. In particular, the temporal progression of the concentration of the Parts in the exhaust gas can be compared or related to the original concentration of the process gas in the feed gas to assess the current purification progress.

In addition to the process gas, according to one possible embodiment, the feed gas comprises a carrier gas, for example, nitrogen, argon, and/or helium. The carrier gas does not participate in the purification reaction. Furthermore, the feed gas containing methane acid may contain hydrogen. The feed gas containing hydrogen as the process gas may comprise essentially exclusively hydrogen or additionally the carrier gas and, for example, argon and/or helium. The hydrogen concentration in the feed gas may be between 4% and 100% and may, for example, be at least 5%, 10%, 20%, 50%, or 75%, or at most 75%, 50%, 20%, 10%, or 5%.

The methane acid concentration in the feed gas may range from 0.1% to 30% and may, for example, be at least 1%, 5%, 10%, 15% or 20% or at most 20%, 15%, 10%, 5% or 1%.

According to one possible embodiment, the environment of the surface to be cleaned is evacuated so that the ambient pressure before the supply gas is supplied to the surface is between 0.01 mbar and 500 mbar absolute. For example, the ambient pressure before the supply gas is supplied is 0.05 mbar, 0.1 mbar, 0.25 mbar, 0.5 mbar, 1 mbar, 10 mbar, 25 mbar, 50 mbar, 100 mbar, or 250 mbar.

According to one possible embodiment, the gas pressure during cleaning in the area of the surface to be cleaned can be up to 2000 mbar absolute and, for example, at least 500 mbar, 750 mbar, 1000 mbar, 1250 mbar, 1500 mbar or 1750 mbar.

According to a possible embodiment, at least one of the two sensor devices is an optical spectral sensor comprising a light source, in particular an infrared light source, and a light sensor which converts the intensity of the received light into a sensor signal depending on the wavelength of the light.

Absorption peaks for methane acid can be at wavelengths of 3.4 µm and 5.6 µm, for water at a wavelength of 3.2 µm and for carbon dioxide at a wavelength of 4.2 µm.

According to a possible embodiment, at least one of the sensor devices uses light for optically determining the concentration/proportion with wavelengths in the range of 1 µm to 10 µm.

Additionally, according to one possible embodiment, the moisture, i.e., the water content, in the feed gas is determined during the supply of the feed gas and/or after its supply and measured, for example, using one of the sensor devices. An advantage of this embodiment may be that already present water that was not produced by the purification reaction does not impair the assessment of the purification process.

According to one possible embodiment, the process gas remains on the surface to be cleaned for the cleaning time. Alternatively, the process gas can be continuously or repeatedly passed over the surface to be cleaned, and the components of the exhaust gas can be continuously or repeatedly determined after passing over the surface.

According to one possible embodiment, repeated means at intervals between 1 s and 600 s, for example intervals of at least 25 s, 50 s, 100 s, 200 s, 300 s, 400 s or 500 s or of at most 500 s, 400 s, 300 s, 200 s, 100 s, 50 s or 25 s.

According to one possible embodiment, the surface to be cleaned is brought and heated, for example, to a temperature between 100 °C and 500 °C, for example from temperatures of up to 120 °C, 140 °C, 150 °C, 180 °C, 200 °C, 250 °C, 300 °C, 350 °C, or 400 °C, for cleaning with methane acid or with hydrogen as process gas.

In summary, the invention relates to the cleaning of surfaces to be joined from interfering impurities, such as oxides, using a process gas. In order to carry out the cleaning efficiently and while reducing or even avoiding undesirable effects, the concentration of the process gas is adjusted before contact of the process gas with the surface. in a feed gas and the composition of at least parts of an exhaust gas containing reaction products of the cleaning and to use the process gas concentration and the exhaust gas composition to evaluate the current cleaning progress.

Figur 1

ein Ausführungsbeispiel einer erfindungsgemäßen Oberflächenreinigungsvorrichtung in einer schematischen Schnittansicht,

Figur 2

ein Ausführungsbeispiel einer erfindungsgemäßen Sensoreinrichtung der erfindungsgemäßen Oberflächenreinigungsvorrichtung des Ausführungsbeispiels der Figur 1 in einer schematischen Schnittansicht, und

Figur 3

ein Ausführungsbeispiel eines erfindungsgemäßen Reinigungsverfahrens schematisch als Flussdiagramm.

The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show:

Figure 1

an embodiment of a surface cleaning device according to the invention in a schematic sectional view,

Figure 2

an embodiment of a sensor device according to the invention of the surface cleaning device according to the invention of the embodiment of the Figure 1 in a schematic sectional view, and

Figure 3

an embodiment of a cleaning method according to the invention schematically as a flow chart.

The invention is explained below by way of example using embodiments with reference to the drawings. The different features of the embodiments can be combined independently of one another, as already explained for the individual advantageous embodiments.

First, the structure and function of a surface cleaning device according to the invention are described with reference to the embodiment of the Figure 1 described.

Figure 1 shows the surface cleaning device 1 schematically in a sectional view. The surface cleaning device 1 has a cleaning chamber 2, which can be designed as a vacuum chamber. Two elements 3 to be connected to one another are removably arranged in the cleaning chamber 2, the surfaces 4 of which are to be cleaned.

The surface cleaning device 1 may have a supply line 5 for supplying a supply gas 6 containing the process gas to the cleaning chamber 2. In order to start, stop or accelerate the supply of the supply gas 6 and In order to be able to slow down, the supply line 5 can have a supply valve 7 through which the supply gas 6 can flow into the cleaning chamber 2.

The surface cleaning device 1 may have a discharge line 8 for discharging an exhaust gas 9 from the cleaning chamber 2. In order to start, stop, or accelerate or slow down the discharge of the exhaust gas 9, the discharge line 8 may have a discharge valve 10 through which the exhaust gas 9 can flow out of the cleaning chamber 2.

The following elements of the surface cleaning device 1 can be provided as a retrofit kit 20 for the surface cleaning device 1 described so far or as a component of the surface cleaning device 1.

The surface cleaning device 1 is further shown with a first sensor device 21, a second sensor device 22, 22A and a cleaning evaluation device 23.

The first sensor device 21 is designed to measure the concentration of the process gas in a feed gas 6. For example, the first sensor device 21 is designed to measure the feed gas 6 flowing through the feed line 5. For this purpose, the first sensor device 21 can be arranged downstream of the feed valve 7 in a flow direction extending through the feed line 5 in the direction toward the cleaning chamber 2. Alternatively, the first sensor device 21 can be arranged upstream of the feed valve 7 in the flow direction extending through the feed line 5 in the direction toward the cleaning chamber 2.

The first sensor device 21 can be an optical sensor device that spectrographically measures the feed gas 6 to determine the concentration of the process gas. The first sensor device 21 is connected to the cleaning evaluation device 23 in a sensor signal-transmitting manner, or at least connectable, for example, via a signal line 24.

The second sensor device 22 is designed to measure the composition of at least parts of an exhaust gas containing reaction products of the purification.

For example, the second sensor device 22 is designed to measure the exhaust gas 9 flowing through the discharge line 8. For this purpose, the second The first sensor device 22 can be arranged upstream of the discharge valve 10 in a flow direction extending through the discharge line 8 in the direction away from the cleaning chamber 2. Alternatively, the second sensor device 22 can be arranged downstream of the discharge valve 10 in the flow direction extending through the discharge line 8 in the direction away from the cleaning chamber 2.

The second sensor device 22 can be an optical sensor device which spectrographically measures the exhaust gas 9 in order to determine the composition of at least parts of the exhaust gas 9 containing reaction products of the cleaning. The second sensor device 22 is connected to the cleaning evaluation device 23 in a sensor signal-transmitting manner or is at least connectable, for example by means of a signal line 25.

Alternatively or in addition to the second sensor device 22, the sensor device 22A can be provided. For example, the sensor device 22A is designed to measure the composition of at least parts of the gas resting above the surface 4 or the surfaces 4 or flowing past the surface 4 or the surfaces 4, which gas already contains reaction products and can thus be referred to as exhaust gas. As an alternative to the position shown, the sensor device 22A can be positioned in the flow direction of the supply gas 6 pointing into the cleaning chamber 2 and/or in the flow direction of the exhaust gas 9 pointing out of the cleaning chamber 2 such that the sensor device 22A measures the exhaust gas 9 behind the surface or surfaces 4 and in particular between the surface or surfaces 4 and the discharge line 8.

The sensor device 22A can be an optical sensor device that spectrographically measures the exhaust gas 9 in order to determine the composition of at least parts of the exhaust gas 9 containing the reaction products of the purification. The sensor device 22A is connected to the purification evaluation device 23 in a sensor signal-transmitting manner, or at least connectable, for example, via a signal line 25A.

Depending on whether the sensor device 22A is provided alternatively or in addition to the second sensor device 22, the sensor device 22A can be referred to as the second or third sensor device 22A.

Furthermore, the cleaning evaluation device 23 can have a signal output 26 and can be designed to output control signals for controlling cleaning process parameters, for example process gas concentration and/or surface temperature, of the surface cleaning via the signal output 26.

A vacuum connection device can be connected downstream of the surface cleaning device 1. Alternatively, the surface cleaning device 1 can be integrated into a vacuum connection device, so that the cleaning chamber can also be designed as a heating furnace for thermally connecting surfaces to be joined.

Figure 2 shows an embodiment of one of the sensor devices 21, 22, 22A of the surface cleaning device 1 according to the invention of the embodiment of the Figure 1 in a schematic sectional view.

The sensor device 21, 22, 22A may be an optical sensor device 21, 22, 22A and include a light source 30. During operation, the light source 30 emits measuring light 31, which passes through the supply gas 6 or the exhaust gas 9 and strikes a light sensor 31. The light sensor 31 measures the received measuring light 31 and transmits a sensor signal representing the received measuring light 31 to the cleaning evaluation device 23.

For example, the light source 30 emits measuring light 31 in the infrared spectrum, i.e., with a wavelength between 800 nm and 1 mm or, for example, between 1 µm and 10 µm. The light sensor 31 generates the sensor signal depending on the wavelength and intensity of the received measuring light 31. Each or selected ones of the sensor devices 21, 22, 22A can thus be designed as infrared spectrometers.

Figure 3 shows an embodiment of a cleaning method 40 according to the invention for cleaning a surface 4, in which the surface 4 is cleaned with a process gas, schematically as a flow chart.

In a first method step 41, the cleaning process 40 can start, for example by providing the element 3 with the surface 4 to be cleaned. In the following method step 42, the element 3 with the surface 4 to be cleaned can The surface 4 to be cleaned can be fed and/or preheated to the surface cleaning device 1. In the subsequent method step 43, the area surrounding the surface 4 to be cleaned can be evacuated until the ambient pressure, for example within the cleaning chamber 2, reaches a predetermined absolute value.

Once the specified ambient pressure has been reached, the process gas can be supplied to the surface 4 in the subsequent process step 44. For example, the supply gas 6 containing the process gas is passed through the supply line 5 and past the first sensor unit 21 into the cleaning chamber 2. During process step 44, the concentration of the process gas in the supply gas 6 is measured using the first sensor device 21.

When the feed gas 6 containing the process gas reaches the surface 4, process step 45 begins, and thus the actual cleaning of the surface 4 by reaction of the process gas with oxides on the surface 4. The feed gas 6 containing the process gas can remain on the surface 4 or be guided along it continuously or repeatedly. If the sensor device 22A is provided, the sensor device 22A can measure the composition of at least parts of the exhaust gas 9 containing the cleaning reaction products during process step 45, as long as the exhaust gas 9 is located in the cleaning chamber 2.

Alternatively, the exhaust gas 9 can be at least partially passed through the discharge line 8 and past the sensor device 22 in order to measure the composition of at least parts of the exhaust gas 9 containing the reaction products of the purification. The discharged exhaust gas 9 can be replaced by feed gas 6, the process gas concentration of which can be measured by the sensor device 21.

Based on the process gas concentration and the composition of at least parts of the exhaust gas 9 containing the reaction products of the cleaning, the cleaning can be evaluated in the following process step 46. If the evaluation shows that the cleaning is not proceeding as intended, process parameters, such as the temperature of the surface 4 or the process gas concentration in the feed gas 6 or in the cleaning chamber 2, can be adjusted in the optional process step 47. If, however, the evaluation shows that the cleaning If the cleaning process proceeds as expected, i.e., according to a predetermined cleaning progress, the process parameters can remain unchanged. If the evaluation shows that the cleaning is complete, for example, because new reaction products are only being formed at a low rate or are no longer being produced to a significant extent, the method 40 can continue with method step 48, in which the exhaust gas is removed from the cleaning chamber 2 and, for example, suctioned off or purged with an oxygen-free gas, for example, nitrogen.

The element 3 having the now cleaned surface 4 can then be cooled in process step 49 and/or removed from the cleaning chamber 2 and fed to the vacuum joining process, for example the vacuum joining device, and soldered in process step 50.

If the surface cleaning device 1 is part of the vacuum bonding device, process step 48 can be followed by process step 51, in which the area surrounding the surface 4, for example, the cleaning chamber 2, is evacuated. In the following process step 52, the surface 4 can be firmly bonded to another surface, for example by soldering or sintering, optionally after transfer to the vacuum bonding device or in the cleaning chamber 2 in a vacuum. Once the bonding step 52 is completed, the area surrounding the now bonded surface 4 can be ventilated, for example with nitrogen or air, and the process can end with the discharge of the element 3 in process step 49.

For example, the actual loading and unloading can take place outside the soldering device, such as a soldering furnace. If it's a single-chamber soldering device, soldering can begin immediately after cleaning in the same chamber. If it's a multi-chamber soldering device, "unloading" can mean that the solder is transported to the next chamber after cleaning and soldered there.

List of reference symbols

1

Surface cleaning device

2

cleaning chamber

3

element

4

surface

5

supply line

6

Supply gas

7

supply valve

8

Discharge line

9

exhaust

10

discharge valve

20

Retrofit kit

21

first sensor device

22

second sensor device

22A

second/third sensor device

23

Cleaning assessment facility

24, 25 25A

Signal line

30

light source

31

measuring light

32

Light sensor

40

Cleaning process

41

start

42

Loading/Preheating

43

Vacuum forming

44

Supply process gas

45

Clean and measure

46

Rate cleaning

47

Change parameters

48

Suction/rinse

49

Unloading/Cooling (or End)

50

End (soldering)

51

Vacuum forming

52

Solder

53

Ventilate

Claims (14)

1. A cleaning method (40) for cleaning a surface (4), in which the surface (4) is cleaned (45) with a process gas, wherein

   a supply gas (6) containing the process gas is guided (44) to the surface (4) and, during the cleaning of the surface (4), an exhaust gas (9) containing reaction products of the cleaning is produced,

   the proportion of the process gas in the supply gas (6) is measured (44),

   the proportion of the process gas and/or the proportion of the reaction products in the exhaust gas (9) is measured (45), and

   the current cleaning progress of the surface (4) is determined (46) based on a comparison of the proportion of the process gas in the supply gas (6) with the proportion of the process gas and/or the proportion of the reaction products in the exhaust gas (9).
2. The cleaning method (40) according to Claim 1, characterized in that cleaning process parameters are changed (47) when the current cleaning progress is not within an expected range.
3. The cleaning method (40) according to Claim 1 or 2, characterized in that the exhaust gas (9) is guided away from the surface (4) when the comparison of the proportions shows that the cleaning corresponds to a predetermined minimum cleaning.
4. The cleaning method (40) according to any one of Claims 1 to 3, characterized in that the process gas is formic acid or hydrogen gas.
5. A vacuum connection method for securely connecting two surfaces (4) to each other, in which at least one of the surfaces (4) to be connected is first cleaned (45) and then connected (50, 52) to the other surface (4), characterized in that, for cleaning the at least one of the surfaces to be connected, the cleaning method (40) according to any one of Claims 1 to 4 is performed.
6. The vacuum connection method according to Claim 5, characterized in that the two surfaces (4) to be connected to each other are securely connected to each other by materially joining them, in particular by brazing or sintering.
7. A retrofitting set (20) for a surface cleaning device (1) for cleaning surfaces (4) with a process gas, wherein

   the retrofitting set (20) includes a first sensor apparatus (21), a second sensor apparatus (22, 22A), and a cleaning assessment apparatus (23), and wherein

   the first sensor apparatus (21) is configured to measure the proportion of the process gas in a supply gas (6),

   the second sensor apparatus (22, 22A) is configured to measure the proportion of the process gas and/or the proportion of the reaction products in an exhaust gas (9) produced during the cleaning of a surface (4) with the process gas, and

   the cleaning assessment apparatus (23) has a sensor signal input port for each of the sensor apparatuses (21, 22, 22A) and is configured to assess the current cleaning progress of the surface (4) based on a comparison of the proportion of the process gas in the supply gas (6) with the proportion of the process gas and/or the proportion of the reaction products in the exhaust gas (9).
8. The retrofitting set (20) according to Claim 7, characterized in that the cleaning assessment apparatus (23) has at least one signal output port (26) and the cleaning assessment apparatus (23) is configured to output control signals for controlling cleaning process parameters of the surface cleaning via the signal output port (26).
9. The retrofitting set (20) according to Claim 7 or 8, characterized in that the cleaning assessment apparatus (23) is configured to output a cleaning end signal when the comparison of the proportion of the process gas in the supply gas (6) with the proportion of the process gas and/or
   the proportion of the reaction products in the exhaust gas (9) shows that the cleaning corresponds to a predetermined minimum cleaning.
10. A surface cleaning device (1) for cleaning a surface (4) with a process gas, including a cleaning chamber (2) for accommodating an element (3) having a surface (4) to be cleaned,
    characterized in that the surface cleaning device (1) includes the retrofitting set (20) according to any one of Claims 7 to 9.
11. A vacuum connection device for securely connecting two surfaces (4) to each other in a vacuum, including a surface cleaning device (1), characterized in that the surface cleaning device (1) is the surface cleaning device according to Claim 10.
12. The vacuum connection device according to Claim 11, characterized in that the vacuum connection device comprises the surface cleaning device (1) or adjoins thereto whilst maintaining a vacuum.
13. The vacuum connection device according to Claim 12, characterized in that the vacuum connection device is a vacuum brazing device or a vacuum sintering system.
14. The vacuum connection device according to Claim 12 or 13, characterized in that the surface cleaning device (1) of the vacuum connection device is arranged upstream of the vacuum connection device along a processing pathway or is integrated into the vacuum connection device.

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