This application is a 371 National Phase of PCT Application No. PCT/EP2018/067462, filed on Jun. 28, 2018; which claims priority to European Patent application 17179102.3 filed Jun. 30, 2017 and each of which is herein incorporated by reference in its entirety.

The invention relates to a vacuum valve having a sensor arrangement with at least one temperature sensor having a deformation-sensitive element.

Vacuum valves for regulating a volume or mass flow and/or for essentially gas-tight closing of a flow path leading through an opening formed in a valve housing are generally known from the prior art in various embodiments and are used in particular in vacuum chamber systems in the area of IC, semiconductor or substrate production, which must take place in a protected atmosphere as far as possible without the presence of contaminating particles. Such vacuum chamber systems comprise in particular at least one evacuatable vacuum chamber which is provided for receiving semiconductor elements or substrates to be processed or produced and which has at least one vacuum chamber opening through which the semiconductor elements or other substrates can be guided into and out of the vacuum chamber, and at least one vacuum pump for evacuating the vacuum chamber. For example, in a production plant for semiconductor wafers or liquid crystal substrates, the highly sensitive semiconductor or liquid crystal elements pass sequentially through several process vacuum chambers in which the parts located within the process vacuum chambers are each processed by means of a processing device. Both during the machining process within the process vacuum chambers and during the transport from chamber to chamber, the highly sensitive semiconductor elements or substrates must always be in a protected atmosphere—especially in an airless environment.

For this purpose, peripheral valves are used to open and close a gas inlet or outlet and transfer valves are used to open and close the transfer openings of the vacuum chambers for inserting and removing the parts.

The vacuum valves through which semiconductor parts pass are referred to as vacuum transfer valves due to the area of application described and the associated dimensioning, as rectangular valves due to their mainly rectangular opening cross-section and also as slide valves, rectangular sliders or transfer slide valves due to their normal mode of operation.

Peripheral valves are used in particular to control or regulate the gas flow between a vacuum chamber and a vacuum pump or another vacuum chamber. For example, peripheral valves are located within a pipe system between a process vacuum chamber or a transfer chamber and a vacuum pump, the atmosphere or another process vacuum chamber. The opening cross-section of such valves, also known as pump valves, is generally smaller than that of a vacuum transfer valve. Peripheral valves are also called regulating valves because, depending on the application, they are not only used to completely open and close an opening, but also to control or regulate a flow by continuously adjusting the opening cross-section between a complete open position and a gas-tight closed position. A possible peripheral valve for controlling or regulating the gas flow is the pendulum valve.

In a typical pendulum valve, as known for example from U.S. Pat. No. 6,089,537 (Olmsted), the first step is to rotate a normally round valve disk from a position that releases the opening to an intermediate position that covers the opening via an opening that is usually also round. In the case of a slide valve, as described for example in U.S. Pat. No. 6,416,037 (Geiser) or U.S. Pat. No. 6,056,266 (Blecha), the valve disk, as well as the opening, is usually shaped rectangular and in this first step is pushed linearly from a position releasing the opening into an intermediate position covering the opening. In this intermediate position, the valve disk of the pendulum or slide valve is located at a distance from the valve seat surrounding the opening. In a second step, the distance between the valve disk and the valve seat is reduced so that the valve disk and the valve seat are pressed evenly against each other and the opening is closed essentially gas-tight. This second movement preferably occurs in a direction substantially perpendicular to the valve seat. The sealing can, for example, take place either via a sealing ring arranged on the closing side of the valve disk, which is pressed onto the valve seat surrounding the opening, or via a sealing ring on the valve seat, against which the closing side of the valve disk is pressed. Due to the two-step closing process, the sealing ring between the valve disk and the valve seat is subjected to hardly any shear forces that would destroy the sealing ring, as the movement of the valve disk in the second step takes place essentially in a straight line perpendicular to the valve seat.

Various prior art sealing devices are known, for example from U.S. Pat. No. 6,629,682 B2 (Duelli). A suitable material for sealing rings and seals in vacuum valves is, for example, fluororubber, also known as FKM, in particular the fluoroelastomer known under the trade name “Viton”, and perfluororubber, FFKM for short.

From the prior art, different drive systems are known to achieve this combination of a rotational and a translational movement of the valve disk parallel to the opening of the pendulum valve and a substantially translational movement perpendicular to the opening of the slide valve, for example from U.S. Pat. No. 6,089,537 (Olmsted) for a pendulum valve and from U.S. Pat. No. 6,416,037 (Geiser) for a slide valve.

The valve disk must be pressed against the valve seat in such a way that both the required gas tightness within the entire pressure range is ensured and damage to the sealing medium, in particular the sealing ring in the form of an O-ring, caused by excessive pressure loading is avoided. In order to guarantee this, well-known valves provide for pressure regulation of the valve disk which is regulated depending on the pressure difference prevailing between the two valve disk sides. Especially with large pressure fluctuations or the change from vacuum to overpressure, or vice versa, an even force distribution along the entire circumference of the sealing ring cannot always be guaranteed. In general, the aim is to decouple the sealing ring from support forces resulting from the pressure applied to the valve. In U.S. Pat. No. 6,629,682 (Duelli), for example, a vacuum valve with a sealing medium is proposed, which consists of a sealing ring and an adjacent support ring, so that the sealing ring is essentially free of support forces.

In order to achieve the required gas tightness, possibly for both positive and negative pressure, some well-known pendulum valves or slide valves additionally or alternatively to the second movement step provide a valve ring which can be displaced perpendicularly to the valve disk, surrounds the opening and is pressed onto the valve disk to close the valve in a gas-tight manner. Such valves with valve rings that can be actively displaced relative to the valve disk are known, for example, from DE 1 264 191 B1, DE 34 47 008 C2, U.S. Pat. No. 3,145,969 (von Zweck) and DE 77 31 993 U. U.S. Pat. No. 5,577,707 (Brida) describes a pendulum valve with a valve housing having an opening and a valve disk that swivels parallel across the opening to control flow through the opening. A valve ring, which surrounds the opening, can be actively moved vertically in the direction of the valve disk by means of several springs and compressed air cylinders. A possible further development of this pendulum valve is proposed in US 2005/0067603 A1 (Lucas et al.).

Since the valves mentioned above are used, among other things, in the production of highly sensitive semiconductor elements in a vacuum chamber, a corresponding sealing effect must also be reliably guaranteed for such process chambers. For this purpose, the condition of the entire valve or in particular of a sealing material or a sealing surface in contact with the sealing material during compression is of particular importance. During the service life of a vacuum valve, changes in valve components can typically occur due to wear of the sealing material or the sealing surfaces as well as structural changes of the valve components, e.g. drive unit or valve stem, due to environmental influences (temperature, humidity, shocks, etc.).

In order to avoid possible leakage or to maintain the quality of the seal at a constant sufficiently high level, a valve closure can typically be replaced at certain intervals. Such a maintenance cycle is usually measured by the number of opening and closing cycles to be expected within a certain period or by the number and severity of environmental influences. Maintenance is typically carried out as a precaution in order to be able to exclude the occurrence of a leak as far as possible in advance.

Such a maintenance requirement is not limited to the sealing material or the valve disk alone, but extends in particular to other valve components such as the drive unit or the valve seat, which forms a part of the vacuum valve corresponding to the valve disk. The structure of a sealing surface on the side of the valve seat, e.g. a groove embedded in the valve seat, is also affected by mechanical stress. Therefore, a structural change in the groove or valve seat resulting from valve operation may also affect the seal. This, too, is usually done at appropriate maintenance intervals.

A disadvantage of this valve maintenance is its precautionary character. Parts affected by maintenance are usually renewed or replaced before their regular or actual life expires. Each such maintenance step usually means a certain downtime for a production process and an increased technical and financial effort. In sum, this means a standstill in production at intervals that are shorter than necessary and more frequent than would be necessary at all.

In addition, parts of the valve, e.g. the drive unit, are typically not replaced or renewed as part of regular and precautionary maintenance. However, even if such a component were to be replaced regularly, it would remain exposed to any external and internal influences even in a quasi-new condition, which could result in undesirable changes to the valve, for example, at least temporarily. For example, a deviation of an adjustment travel for the valve closure caused by this can lead to the consequence that a target sealing effect cannot be achieved any longer.

The invention is therefore based on the object of providing an improved vacuum valve, which allows an optimized operation of the vacuum valve.

It is a further object of the invention to provide an improved vacuum valve, which allows optimized valve maintenance and thus an improvement, i.e. a shortening of possible process stoppages.

A further object of the invention is to provide such a valve system, with which a more reliable gas-tight sealing of a process volume can be achieved, in particular wherein the quality of the sealing is predictable.

These objects are solved by the realization of the characterizing features of the independent claims. Features which further develop the invention in an alternative or advantageous way can be found in the dependent patent claims.

The basic idea of the present invention is to combine a vacuum valve with a sensor arrangement with at least one temperature sensor and to design the valve and the sensor arrangement in such a way that a detection and/or monitoring of thermal influences or events at a certain part of the valve or at the valve as a whole can take place.

For example, the temperature can be measured on a drive housing in the area of temperature-critical components, such as a pneumatic cylinder or sensors. An alternative measuring point is directly on the vacuum housing. The temperature that can be measured in this way can be used to record the status of the valve. For example, an increased temperature may be an indicator of a related change in valve activity. This may result in increased play of the drive unit. By knowing the temperature effect and simultaneously measuring the temperature, the functional safety of the valve can always be monitored and adjusted.

Based on the information collected in this way, a valve actuation can be adapted. If, for example, a high temperature is measured and it is also known how this temperature influences the behavior of the valve, an adjustment of the drive unit control can compensate for a possible negative effect. If, for example, a changed bending behavior of the drive unit or a valve stem is to be expected, a higher contact pressure (on the seal) can be set.

Other parameters and measurement data that influence the behavior of the valve can also be taken into account when adapting the controller.

In general, the temperature sensor allows information to be generated as to whether a measured temperature is within a target range or whether the temperature exceeds a defined threshold value. For this purpose, the valve or its processing and control unit has correspondingly stored target data for alignment with current measured values.

By monitoring and, optionally, recording the temperature at the valve over a certain period of time, in particular continuously from commissioning, information can be generated with reference to a temperature-dependent service life of the valve. For example, a temperature- and time-induced change of a sealing material can be detected and the necessity of a replacement of the sealing material can be indicated. The operation of the valve outside an ideal temperature range and the duration of this operation can also be recorded and evaluated with regard to an effect on the life expectancy of certain valve components.

A PT100 element, for example, can be used as a temperature sensor. At 0° C. this has an electrical resistance of 100 ohm. At higher temperatures, this resistance increases in a known way. The resistance can be measured and evaluated accordingly, allowing an absolute temperature to be determined. An element can be used which can be mounted directly on a metallic surface of the valve so that the surface temperature of at least this part can be measured.

Alternative state-of-the-art temperature sensors are also conceivable. For example, an optical sensor that provides measurement data using infrared radiation can be used.

By monitoring the valve temperature, maintenance intervals can be better planned and carried out more efficiently, while at the same time maintaining and safeguarding process integrity.

The invention relates to a vacuum valve, in particular a vacuum slide valve, a pendulum valve or a monovalve, for regulating a volume or mass flow and/or for gas-tight interruption of a flow path. The valve has a valve seat which has a valve opening defining an opening axis and a first sealing surface surrounding the valve opening, a valve closure, in particular a valve disk, for regulating the volume or mass flow and/or for interrupting the flow path, with a second sealing surface corresponding to the first sealing surface, and a drive unit coupled to the valve closure.

The output unit is designed such that the valve closure is adjustable from an open position, in which the valve closure and the valve seat are contactless relative to one another, to a closed position, in which there is sealing contact between the first sealing surface and the second sealing surface via an interposed seal and the valve opening is thereby closed in a gas-tight manner, and back again.

The drive unit can be designed as an electric motor, e.g. stepper motor, or as a pneumatic drive.

The vacuum valve has at least one temperature sensor, wherein the temperature sensor is designed and arranged in such a way that a measurement signal representing thermal information relating to at least part of the vacuum valve can be detected by means of the temperature sensor.

The temperature sensor is thus able to provide a measurement signal which makes it possible to derive a thermal state of the valve or a component of the valve, wherein the signal can, for example, be processed directly in a processing and control unit or output as visual or acoustic information.

In one embodiment, the temperature sensor can, for example, be arranged on the drive unit.

The drive unit can in particular be designed as a pneumatic drive and the temperature sensor can be arranged on a pneumatic cylinder of the drive unit.

In such an arrangement, the temperature sensor can record the thermal information with direct reference to an operating state of the drive unit, i.e. the measurement signal of the temperature sensor provides direct information on a function of opening and closing the valve. For example, an increase in the operating temperature can lead to an increase in elasticity in the system, which can then be detected and compensated for.

According to a further embodiment, the temperature sensor can be arranged at the valve closure or the valve seat. This makes it possible, for example, to monitor the condition of the seal, e.g. of a polymer-based sealing material. At low temperatures the material can be considerably stiffer than at high temperatures and the drive can be adapted accordingly to the thermal material behavior, e.g. with regard to a target contact pressure.

The vacuum valve can have a valve housing in one embodiment and the temperature sensor can be arranged on the valve housing. With this embodiment the thermal information concerning the housing can be recorded. For example, external influences on the valve (e.g. changes in the ambient temperature) can be measured.

In one embodiment, the temperature sensor can be designed as a hot conductor or as a PTC thermistor, in particular as a platinum or silicon measuring resistor, in particular as a Pt 100 element. The temperature sensor can also be designed as a semiconductor temperature sensor, in particular an integrated semiconductor temperature sensor, as an optical temperature sensor, in particular an infrared thermometer, or as a thermocouple. In the context of this invention, these variants of temperature sensors should not be regarded as conclusive, but rather as alternative sensor types that can provide a thermal measurement signal.

The thermal information is represented in particular by a temperature, but can also be expressed, for example, in the form of thermal energy.

According to one embodiment, the measurement signal can be continuously recorded. For this purpose, the vacuum valve may have a processing and control unit configured accordingly with an algorithm. The continuous recording provides continuous monitoring and checking of the valve function as a function of a thermal condition.

In one embodiment, the drive unit of the vacuum valve can be actuated in a controlled manner by a processing and control unit of the vacuum valve with control values for adjusting the valve closure between the open position and the closed position. In particular, the processing and control unit is then set up in such a way that the control values are automatically set depending on the currently acquired measurement signal. Thus an automatic compensation of temperature-dependent (negative) effects can be provided.

According to one embodiment of the invention, the vacuum valve can have a processing and control unit designed in such a way that the detected measurement signal can be processed by means of the processing and control unit and status information is generated on the basis of the detected measurement signal. An output signal can be provided based on a comparison of the status information with a predefined tolerance value.

In particular, the status information relating to a mechanical and/or structural integrity of the drive unit, the valve seat and/or the valve closure can be provided, in particular wherein the status information is generated by means of an actual-target comparison for the detected measurement signal.

The invention also relates to a method for controlling a vacuum valve, in particular a vacuum slide valve, pendulum valve or monovalve, wherein the vacuum valve is designed to regulate a volume or mass flow and/or to interrupt a flow path in a gas-tight manner. The vacuum valve has a valve seat which has a valve opening defining an opening axis and a first sealing surface surrounding the valve opening, and a valve closure, in particular a valve disk, for regulating the volume or mass flow and/or for interrupting the flow path, with a second sealing surface corresponding to the first sealing surface, the variable position of which is determined by a respective position and orientation of the valve closure. A drive unit coupled to the valve closure and having at least one movable adjustment element is also provided, wherein the drive unit is designed to carry out an adjusting movement so that the valve closure can be adjusted from an open position, in which the valve closure and the valve seat are present without contact relative to one another, to a closed position, in which, in particular via a seal, there is sealing contact between the first sealing surface and the second sealing surface and the valve opening is thereby closed in a gas-tight manner, and back again.

During the process, in particular continuously, thermal information relating to at least part of the vacuum valve is recorded.

In one embodiment, the thermal information can be recorded periodically during a certain period of time, in particular continuously, and a temperature-time curve can be derived. This allows a change in the status of the valve over a certain period of time to be logged, analyzed and, for example, processed into an alarm signal or a maintenance request.

In other words, output information relating to a valve state can be generated on the basis of the temperature-time curve, in particular the output information indicating a reference of a current temperature to a temperature threshold value, in particular an exceeding of the temperature threshold value. The output information can also indicate an effect of the temperature-time curve on an operating condition of the valve, in particular on process reliability, valve service life and/or an expected valve maintenance time.

The invention also relates to a computer program product having program code which is stored on a machine-readable carrier, in particular a control and processing unit of a vacuum valve described above, or a computer data signal embodied by an electromagnetic wave, for carrying out the acquisition of the thermal information and/or in particular a process described above.

The vacuum valve according to the invention is described in more detail below by means of embodiment examples schematically shown in the drawings. The same elements are marked in the figures with the same reference numerals. As a rule, the embodiments described are not to scale and are not to be understood as limitations.

